radiation curing: state-of-the-art assessmentinfohouse.p2ric.org/ref/29/28059.pdf · future use of...

Electric Power Research lnst it Ute

Topics: Radiation processing Radiation-processing chemistry End use Technology assessment Technology utilization Electrotechnology

EPRl EM-4570 Project 2613-3

P=#EwS1 Final ReDort J7 June 1986 !or-

Radiation Curing: State-of-the-Art - Assessment

Prepared by Battelle Columbus Division Columbus, Ohio

R E P O R T S U M M A R Y SUBJECT Industrial electric technologies

TOPICS Radiation processing Technology assessment Radiation-processing chemistry Technology utilization '

End use Electrotechnology ~

AUDIENCE Customer service engineers / Marketing managers

Radiation Curing: State-of-the-Art Assessment Radiation curing of polymeric materials offers utilities an oppor- tunity to promote efficient electricity-based processing among their industrial customers. According to this assessment, manufacturing use of the technology is likely to grow from 10 to 20% annually for the next 15 years.

BACKGROUND Radiation curing is an efficient and relatively low temperature electricity- based technology with many applications in coating, printing, adhesives, electronics, and communication materials. Moreover, the application of electromagnetic radiation-from infrared, ultraviolet, high-energy electron, microwave, or radio-frequency sources-can improve the overall physical or chemical properties of polymeric materials to produce results that are superior, in such characteristics as bonding, surface finish, and durability to those of other technologies. Its speed and controllability in these applications, plus the narrowing gap between the costs of electricity and natural gas, suggest an increasing market for this electrotechnology in manufacturing worldwide.

OBJECTIVE To assess the state of the art of radiation-curing technologies as applied to organic substrate materials.

APPROACH After a review of the literature on all aspects of radiation-processing technologies, the project team interviewed U.S., European, and Japanese equipment manufacturers, material suppliers, and end users. Their analysis of this information sought to characterize the major industries making wide use of radiation curing, to clarify the developmental trends, and to evaluate potential applications and market penetration, considering fuel prices and competing technologies.

RESULTS Radiation-processing technologies-widely accepted during the past 15 years in many new and varied industries-offer several major advantages over other production methods. These benefits include rapid curing, low process temperatures, the absence of pollution, and substantially lower energy costs, as well as high-quality and specialized products. Typical product lines involve coatings (on wood, metal, paper, and plastic), inks (for letterpress, lithographic, gravure, and screen printing), and adhesives

EPRl EM-4570s

(for film, foil, or paper substrates). The industries using these technologies engage in such diverse activities as electronics, fiber optics, flooring, packaging, plastics, and plasma processing. Although radiation curing is still a minor manufacturing technique, in future its industrial use is expected to expand greatly-with an annual growth of 10 to 20%.

~

EPRl PERSPECTIVE As electricity costs become more competitive with the costs of natural gas for industrial processing, radiation curing has prospects of becom- ing a key area of growth for electricity-based process heating. Much of that increased growth will come with the development of specialty products or high-value-added products that can be made only by electromagnetic radiation derived from electricity.

PROJECT RP2613-3 EPRl Project Manager: I. Leslie Harry Energy Management and Utilization Division Contractor: Battelle Columbus Division

For further information on EPRl research programs, call EPRl Technical Information Specialists (415) 855-2411.

Radiation Curing: State-of-the-Art Assessment

EM-4570 Research Project 2613-3

L

Final Report, June 1986

Prepared by

BATTELLE COLUMBUS DIVISION 505 King Avenue

Columbus, Ohio 43201

Principal Investigator V. D. McGinniss

Prepared for

Electric Power Research Institute 3412 Hillview Avenue

Palo Alto, California 94304

EPRl Project Manager I. L. Harry

Industrial Program Energy Management and Utilization Division

i

ORDERING INFORMATION

Requests for copies of this report should be directed to Research Reports Center (RRC), Box 50490, Palo Alto, CA 94303, (415) 965-4081. There is no charge for reports requested by EPRl member utilities and affiliates, U.S. utility associations, US. government agencies (federal, state, and local), media, and foreign organizations with which EPRl has an information exchange agreement. On request, RRC will send a catalog of EPRl reports.

Electric Power Research Institute and EPRl are registered service marks of Electric Power Research Institute, Inc.

Copyright 0 1986 Electric Power Research Institute, Inc. All rights reserved

NOTICE This report was prepared by the organization@) named below as an account of work sponsored by the Electric Power Research Institute, Inc. (EPRI). Neither EPRI, members of EPRI, the organization(s) named below, nor any person acting on behalf of any of them: (a) makes any warranty, express or implied, with respect to the use of any information, apparatus, method, or process disclosed in this report or that such use may not infringe privately owned rights; or (b) assumes any liabilities with respect to the use of, or for damages resulting from the use of, any information, apparatus, method, or process disclosed in this report.

Prepared by Battelle Columbus Division Columbus, Ohio

ABSTRACT

I n t h e l a s t 15 years t h e convers ion o f e l e c t r i c a l energy i n t o i n f r a r e d , u l t r a v i o l e t

and h igh energy e l e c t r o n e lec t romagnet ic r a d i a t i o n has gained wor ldwide acceptance

as an e f f i c i e n t and economical method f o r m o d i f y i n g po lymer ic m a t e r i a l s . These

r a d i a t i o n m o d i f i e d polymer systems are assoc ia ted w i t h many d i f f e r e n t types o f

p roduc ts which are produced under a wide d i v e r s i t y o f manufac tur ing o p e r a t i o n s .

T y p i c a l p roduc t l i n e o r a p p l i c a t i o n areas i nc lude : c o a t i n g s (wood, meta l , paper-

packaging, f l o o r - f l e x i b l e p l a s t i c , w i r e , and t r a n s p o r t a t i o n c o a t i n g systems); i n k s ( l e t t e r p r e s s , l i t h o g r a p h y , f lexography, g ravure and screen p r i n t i n g ) ; adhesives

(p ressure s e n s i t i v e tapes and l a m i n a t i o n adhesives f o r f i l m , f o i l o r paper sub-

s t r a t e s ) ; e l e c t r o n i c s ( i n t e g r a t e d c i r c u i t s , p r i n t e d c i r c u i t boards) ; communications

( f i b e r o p t i c s , magnet ic and o p t i c a l media); p l a s t i c s and rubber m a t e r i a l s ( w i r e

and cable, p o l y o l e f i n s h r i n k wrap, p o l y o l e f i n foams); and plasma process ing

(polymer s u r f a c e m o d i f i c a t i o n s and polymer c o a t i n g s ) .

r a d i a t i o n process ing techno log ies over o t h e r methods are:

p rocess ing temperatures, s p e c i a l t y p roduc ts , h i g h q u a l i t y p roduc ts , no p o l l u t i o n

and s u b s t a n t i a l r e d u c t i o n i n energy c o s t s . The t o t a l impact o f r a d a t i o n

process ing o f po lymer ic m a t e r i a l s , w h i l e s i g n i f i c a n t , i s s t i l l o n l y a minor p a r t o f

t h e t o t a l p roduc t manufac tur ing techniques c u r r e n t l y i n use today.

f u t u r e use o f r a d i a t i o n process ing o f po lymer ic m a t e r i a l s i s expected t o expand

d r a m a t i c a l l y . The o v e r a l l annual growth r a t e f o r r a d i a t i o n process ing techniques

i s p r o j e c t e d t o be between 10 t o 20%, thus i t i s an a t t r a c t i v e area f o r f u t u r e

research and development a c t i v i t y .

The major advantages o f

r a p i d cu e, l o w

However, t h e

iii

ACKNOWLEDGMENTS

T h i s r e p o r t i s one o f a s e r i e s o f e l e c t r o t e c h n o l o g y assessments prepared

a t B a t t e l l e ' s Columbus D i v i s i o n i n coopera t i on w i t h t h e E P R I Center f o r Me ta l s

F a b r i c a t i o n . The o v e r a l l p r o j e c t has been conducted under t h e s u p e r v i s i o n o f

M r . Thomas G. By re r , D i r e c t o r o f t h e Center f o r Meta ls F a b r i c a t i o n . Va luab le

i n f o r m a t i o n f o r t h i s r e p o r t was a l s o p r o v i d e d by D r . Lee Semia t i n o f t h e Center f o r

Me ta l s F a b r i c a t i o n Department.

V

.

CONTENTS

Section Page

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

2 RADIATION PROCESSING EQUIPMENT . . . . . . . . . . . . . . . . . . . . 2-1

2-1 Ultraviolet (UV) Light Sources . . . . . . . . . . . . . . . . . . 2-6 High Energy Electron Radiation Processing Equipment . . . . . . . 2-15

Plasma Radiation Processing Equipment . . . . . . . . . . . . . . 2-32

Thermal Radiation Processing Chemistry . . . . . . . . . . . . . . 3-1

UV-Visible Light Processing Chemistry . . . . . . . . . . . . . . 3-5

Infrared Radiation Processing Equipment . . . . . . . . . . . . .

3 RADIATION PROCESSING CHEMISTRY AND MATERIALS . . . . . . . . . . . . . 3-1

Free Radical Photocuring System . . . . . . . . . . . . . . . 3-5 Cationic Photocuring System . . . . . . . . . . . . . . . . 3-7

3-8 High Energy Electron Processing Chemistry . . . . . . . . . . . . Plasma Processing Chemistry . . . . . . . . . . . . . . . . . . . 3-11

Thiol Curing Chemistry . . . . . . . . . . . . . . . . . . . . . 3-10

4 APPL ICATIONS/MARKETS . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Wood Finishings . . . . . . . . . . . . . . . . . . . . . . . 4-5

Packaging Coatings . . . . . . . . . . . . . . . . . . . . . 4-13 Metal Decorative Coatings . . . . . . . . . . . . . . . . . . 4-6

Floor Coatings . . . . . . . . . . . . . . . . . . . . . . . 4-18 Wire Coatings . . . . . . . . . . . . . . . . . . . . . . . . 4-18 Transportation (Automotive) Coatings . . . . . . . . . . . . 4-22

Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-22

Letterpress Process . . . . . . . . . . . . . . . . . . . . . 4-26 Lithography . . . . . . . . . . . . . . . . . . . . . . . . . 4-26

Flexography . . . . . . . . . . . . . . . . . . . . . . . . . 4-26 Gravure . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-30 Screen Printing . . . . . . . . . . . . . . . . . . . . . . . 4-31 Radiation Curing Applications in Printing . . . . . . . . . . 4-31

Adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-35

vi i

Section

E l e c t r o n i c s and Communications . . . . . . . . . . . . . . . . . . In tegra ted C i r c u i t s ( I C ) . . . . . . . . . . . . . . . . . . Li thography . . . . . . . . . . . . . . . . . . . . . . . . . Adhesives and Encapsulants . . . . . . . . . . . . . . . . . P r i n t e d C i r c u i t Boards . . . . . . . . . . . . . . . . . . . F i b e r Opt ics . . . . . . . . . . . . . . . . . . . . . . . . Magnetic and Opt ica l Media . . . . . . . . . . . . . . . . . .

P l a s t i c s and Rubber M a t e r i a l s . . . . . . . . . . . . . . . . . . Plasma Processing . . . . . . . . . . . . . . . . . . . . . . . .

5 COST AND ENERGY SAVINGS COMPARISONS . . . . . . . . . . . . . . . . . . Cost Comparison . Radiat ion Processing Versus Thermal Processing Technologies . . . . . . . . . . . . . . . . . . . . .

Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . P r i n t i n g Inks . . . . . . . . . . . . . . . . . . . . . . . . Adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . Electronics/Communication . . . . . . . . . . . . . . . . . . P l a s t i c and Rubber Mater ia ls . . . . . . . . . . . . . . . .

Plasma Processing . . . . . . . . . . . . . . . . . . . . . . . . Impact o f Fuel Pr ices . . . . . . . . . . . . . . . . . . . . . .

6 SALES HISTORY/MARKET PROJECTIONS . . . . . . . . . . . . . . . . . . . Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wood F i n i s h i n g . . . . . . . . . . . . . . . . . . . . . . . Metal Decorative Coatings . . . . . . . . . . . . . . . . . Packaging Coatings . . . . . . . . . . . . . . . . . . . . . Other Coating Systems . . . . . . . . . . . . . . . . . . . .

P r i n t i n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . Adhesives . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page 4-41 4-48

4-48 4-55

4-59 4-59 4-62 4-66 4-74 5-1

5-1 5-2 5-6 5-10 5-10 5-16 5-19 5-19 6-1 6-1 6-4 6-8 6-12

6-12 6-14 6-19

P l a s t i c s and Rubber Mater ia ls . . . . . . . . . . . . . . . . . . 6-19 E l e c t r o n i c s and Communications . . . . . . . . . . . . . . . . . 6-25 Rad ia t ion Processing Equipment . . . . . . . . . . . . . . . . . . 6-31

Global Trends f o r Radiat ion Processing o f Polymeric M a t e r i a l s . . 6-36 Competit ion From E x i s t i n g and Emerging Technologies . . . . . . . 6-34

7 CONCLUSIONS. FUTURE DEVELOPMENTS AND TECHNICAL V O I D S . . . . . . . . . 7-1 a REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

APPENDIX MANUFACTURERS OF RADIATION PROCESSING EQUIPMENT AND MATERIAL SUPPLIERS . . . . . . . . . . . . . . . . . . . . A - 1

.

. ~~

v i i i

.

ILLUSTRATIONS

F i g u r e Page

1-1 E lec t romagne t i c Spectrum . . . . . . . . . . . . . . . . . . . . . . . 1-2

2 - 1 Schematic o f A p p l i c a t i o n o f Long Wave I R R a d i a t i o n . . . . . . . . . . 2-2

2-2 Schematic o f A p p l i c a t i o n o f Medium Wave I R R a d i a t i o n . . . . . . . . . 2-3

2-3 Schematic o f A p p l i c a t i o n o f S h o r t Wave I R R a d i a t i o n . . . . . . . . . 2-4

2-4 R e l a t i o n s h i p o f I R E m i t t e r Temperature t o Maximum I n t e n s i t y Wavelength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2-5 D i s t r i b u t i o n o f Wavelengths f rom an I R E m i t t e r . . . . . . . . . . . . 2-7

2-6 I R Energy E f f i c i e n c y Cons ide ra t i ons . . . . . . . . . . . . . . . . . 2-8

2-7 S e l e c t i v e Absorp t i on o f I R R a d i a t i o n b y Var ious Subs t ra tes . . . . . 2-10

2-8 Common I R R a d i a t i o n E m i t t e r s . Fue l Bu rn ing Types . . . . . . . . . . 2-11

2-9 Common I R R a d i a t i o n E m i t t e r s . E l e c t r i c a l Types . . . . . . . . . . . 2-12

2-10 E l e c t r i c a l l y A c t i v a t e d Q u a r t z Tube I R E m i t t e r . . . . . . . . . . . . 2-13

2-11 UV/Vis L i g h t Source Power Supp l i es . . . . . . . . . . . . . . . . . 2-16

2-12 UV Lamp Con f igu ra t i ons . . . . . . . . . . . . . . . . . . . . . . . 2-17

2-13

2-14

2-15

2-16

2-17

2- 18

2-19

2-20

2-21

Commerci a1 UV Processor U n i t s . . . . . . . . . . . . . . . . . . . . 2-20

General Schematic o f A High Energy E l e c t r o n Beam Process ing U n i t . . . 2-22

High and Low Energy E l e c t r o n Processor Power Supp l i es . . . . . . . . 2-24

Scanned E l e c t r o n Beam A c c e l e r a t o r System . . . . . . . . . . . . . . . 2-25

Energy Science P lanar Cathode E l e c t r o n C u r t a i n Processor . . . . . . . 2-27

Extended Process ing Zone E l e c t r o n Beam Equipment . . . . . . . . . . 2-28

R a d i a t i o n Polymer C o r p o r a t i o n ' s Modular P lana r Cathode Processor . . . 2-29

H i s t o r i c a l Growth o f E l e c t r o n Beam A c c e l e r a t o r Systems . . . . . . . . 2-30

Comparison Between P lanar Cathode and Swept E l e c t r o n Beam Process ing U n i t s . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31

i x

F i g u r e . Page

2-22 Tubular Reactor f o r Plasma P o l y m e r i z a t i o n . . . . . . . . . . . . . . 2-33

2-23 P a r a l l e l P l a t e E l e c t r o d e Plasma P o l y m e r i z a t i o n Apparatus . . . . . . . 2-34

2-24 A i r - t o - A i r Plasma Process ing System . . . . . . . . . . . . . . . . . 2-35 i

2-25 Example o f Plasma Process ing w i t h Supply and Take-up R o l l s w i t h i n t h e Vacuum Chamber . . . . . . . . . . . . . . . . . . . . . . 2-36

3 - 1

4 - 1

4-2

4-3

4-4

4-5

4-6

4-7

4-8

4-9

4-10

4-11

4-12

4-13

4-14

4-15

4-16

4-17

4-18

4-19

4-20

4-21

R a d i a t i o n Process ing Chemistry . . . . . . . . . . . . . . . . . . . 3-2

Comparison between Convent ional and R a d i a t i o n Curable Coa t ing Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

R a d i a t i o n Curable Wood F i n i s h i n g Technology . . . . . . . . . . . . . 4-7

Wood F i n i s h i n g Operat ions . . . . . . . . . . . . . . . . . . . . . . 4-8

V a r n i s h i n g and UV C u r i n g l F i n i s h i n g L i n e f o r F l a t Stock Wood Products . 4-9

E l e c t r o n Beam Cur ing L i n e f o r Wood Products . . . . . . . . . . . . . 4-11

R a d i a t i o n Curable Can L i n e Opera t i on . . . . . . . . . . . . . . . . . 4-14

Galvanized S t e e l Tubing L i n e . . . . . . . . . . . . . . . . . . . . 4-15

Cross S e c t i o n o f Tube L i n e Surrounded by Three o r Four UV Lamps . . . 4-16

R a d i a t i o n Curable F l o o r Sheet and F l o o r T i l e Product L i n e . . . . . . 4-20

T y p i c a l Wire Coa t ing L i n e s . . . . . . . . . . . . . . . . . . . . . . 4-21

F i n i s h i n g L i n e f o r High-speed I R and UV Curable Coat ings . . . . . . . 4-24

L e t t e r p r e s s Process . . . . . . . . . . . . . . . . . . . . . . . . . 4-27

L i t h o g r a p h y Process . . . . . . . . . . . . . . . . . . . . . . . . . 4-28

F lexography Process . . . . . . . . . . . . . . . . . . . . . . . . . 4-29

Gravure P r i n t i n g Process . . . . . . . . . . . . . . . . . . . . . . 4-32

Screen P r i n t i n g Process . . . . . . . . . . . . . . . . . . . . . . . 4-33

O f f s e t Press Process w i t h UV Cure and EB Cure Process ing U n i t s . . . . 4-36

Dryer C o n f i g u r a t i o n s . . . . . . . . . . . . . . . . . . . . . . . . . 4-37

Adhesive Market Area C l a s s i f i c a t i o n . . . . . . . . . . . . . . . . . 4-39

Adhesive F i l m Systems . . . . . . . . . . . . . . . . . . . . . . . . 4-43

Laminator Coater System . . . . . . . . . . . . . . . . . . . . . . . 4-44

X

F i g u r e Page

4-22 P r i n t e d W i r i n g C i r c u i t Board Showing D iverse Uses o f P l a s t i c M a t e r i a l s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-47

4-23 I C Manufac tur ing Process . . . . . . . . . . . . . . . . . . . . . . . 4-49

4-24

4-25

4-26

4-27

4-28

4-29

4-30

4-31

4-32

4-33

L i t h o g r a p h y Process . . . . . . . . . . . . . . . . . . . . . . . . . 4-51

Schematic o f Contact P r i n t i n g Using P o s i t i v e and Negat ive R e s i s t s . . 4-52

Electron-Beam P a t t e r n i n g System . . . . . . . . . . . . . . . . . . . 4-53

X - Ray L i t h o g r a p h y System . . . . . . . . . . . . . . . . . . . . . . 4-54

Automat ion o f S u r f ace-Mounted Boards . . . . . . . . . . . . . . . . . 4-56

UV Coat ing o f O p t i c a l F i b e r s . . . . . . . . . . . . . . . . . . . . . 4-63

Magnet ic Media Coat ing L i n e w i t h EB Cure . . . . . . . . . . . . . . 4-64

F a b r i c a t i o n o f L a s e r v i s i o n Video Discs . . . . . . . . . . . . . . . 4-67

Electron-Beam Process ing System f o r Wire.Cable . . . . . . . . . . . . 4-71

A p p l i c a t i o n s o f Plasma Process ing Technologies . . . . . . . . . . . 4-78

6 - 1 H i s t o r i c a l Growth P a t t e r n f o r t h e Coat ing I n d u s t r y . . . . . . . . . . 6-3

6-2 Major Market Segments f o r I n d u s t r i a l Product F i n i s h e s . . . . . . . . 6-6

6-3 H i s t o r i c a l Growth P a t t e r n f o r t h e Wood F i n i s h i n g I n d u s t r y . . . . . . 6-7

6-4 Shipments Reported f o r Meta l Decora t ive Coat ings Market . . . . . . . 6-10

6-5 Packaging Coat ing Shipments . . . . . . . . . . . . . . . . . . . . . 6-13

6-6 Shipment Values Reported f o r P r i n t i n g Inks . . . . . . . . . . . . . 6-15

6-7 Market Share o f Major P r i n t i n g Processes . . . . . . . . . . . . . . . 6-16

6-8 Shipments Reported f o r Adhesives I n d u s t r y . . . . . . . . . . . . . . 6-20

6-9 Shipments o f Pressure S e n s i t i v e Adhesives . . . . . . . . . . . . . . 6-22

( P V C ) Annual P l a s t i c s Produc t ion Capac i ty . . . . . . . . . . . . . . 6-23

P o l y v i n y l C h l o r i d e (PVC) . . . . . . . . . . . . . . . . . . . . . . 6-24

6-12 I C Shipments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27

6-13 U.S. E l e c t r o n i c Chemicals . . . . . . . . . . . . . . . . . . . . . . 6-28

6-10 Share o f Low D e n s i t y P o l y e t h y l e n e (LDPE) and P o l y v i n y l C h l o r i d e

1985 Market Share f o r Low D e n s i t y Po lye thy lene (LDPE) and 6-11

.

.

x i

Figure Page

6-14 U.S. Electronic Chemicals for Devices . . . . . . . . . . . . . . . . . 6-29

6-15 U.S. Device Encapsulant Consumption . . . . . . . . . . . . . . . . . 6-30

x i i

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TABLES

Table Page

1-1 E lec t romagne t i c Spectrum . . . . . . . . . . . . . . . . . . . . . . . 1-1

2-1 Normal T o t a l E m i s s i v i t y o f Var ious Subs t ra tes . . . . . . . . . . . . 2-9

2-2 C h a r a c t e r i s t i c s o f Commercial ly Used I n f r a r e d Heat Sources . . . . . . 2-14

2-3 UV Lamp Opera t i ng C h a r a c t e r i s t i c s . . . . . . . . . . . . . . . . . . 2-18

2-4 Opera t i ona l C h a r a c t e r i s t i c s o f E l e c t r o d e and E l e c t r o d e l e s s 2-19

2-5 UV Cur ing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

2-6 2-26

Medium Pressure Mercury Arc Lamp . . . . . . . . . . . . . . . . . . .

Comparisons Between P lanar Cathode and Swept Beam High Energy E l e c t r o n Process ing Equipment . . . . . . . . . . . . . . . . .

3 - 1 I n f r a r e d o r Thermal R a d i a t i o n Process ing Chemist ry . . . . . . . . . 3-4

3-2 P h o t o i n i t i a t o r s Used i n U l t r a v i o l e t R a d i a t i o n Curable Polymer ic M a t e r i a1 s . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

3-3 M a t e r i a l s Used i n R a d i a t i o n (UV and EB) Curable Coat ings . . . . . . . 3-6

3-4 Photocurable Polymer Systems . . . . . . . . . . . . . . . . . . . . . 3-9

4 - 1

4-2 R a d i a t i o n Curable Coat ings f o r Wood F i n i s h i n g A p p l i c a t i o n s . . . . . . 4-10

Coat ings I n d u s t r y . P a i n t s and A l l i e d Products ( S I C 28500-005) . . . . 4-3

4-3 Comparison o f Performance L i m i t s and Test Values Between H igh and Low Pressure Me1 amine Thermal l y Cured Laminates and U n i f ace E l e c t r o n ' Beam Cured Panels . . . . . . . . . . . . . . . . . . . . . . 4-12

4-4 P r o p e r t i e s o f T y p i c a l UV Curable Coat ings f o r Galvanized S t e e l Tubing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17

4-5 Comparison o f P r o p e r t i e s f o r Convent ional and R a d i a t i o n Curab le Coat ings f o r V i n y l F l o o r i n g Products . . . . . . . . . . . . . . . . . 4-19

4-6 Average P r o p e r t i e s o r R a d i a t i o n Curable Coat ings i n Magnet Wire A p p l i c a t i o n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23

4-7 P r i n t i n g I n d u s t r y Product D i v e r s i t y . . . . . . . . . . . . . . . . . 4-25

4-8 Standard (Convent ional Thermal Cure) and UV/EB I n k Fo rmu la t i ons . . . 4-34

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Tab1 e Page

4-9 Adhesives Market S u p p l i e r s and Products . . . . . . . . . . . . . . . 4-38

4-10 Adhesives I n d u s t r y Polymer-Solvent C l a s s i f i c a t i o n . . . . . . . . . . 4-40

4-11 Adhesive Techno1 og i es . . . . . . . . . . . . . . . . . . . . . . . . 4-41

4-12 S t r u c t u r a l and S p e c i a l t y Adhesives Markets . . . . . . . . . . . . . . 4-42

4-13 Advantages o f High-Energy E l e c t r o n Adhesives . . . . . . . . . . . . . 4-42

4-14 T y p i c a l Products Prepared Wi th a Planar Cathode E l e c t r o n Processor . . 4-45

4-15 Adhesive F i l m A p p l i c a t i o n Areas . . . . . . . . . . . . . . . . . . . 4-46

4-16 Photo1 i t h o g r a p h i c Processes . . . . . . . . . . . . . . . . . . . . . 4-55

4-17 P r o p e r t i e s o f Two S t a k i n g Compounds f o r SMD Thermal Versus UV Curable M a t e r i a l s . . . . . . . . . . . . . . . . . . . . . . . . . 4-57

4-18 Adhesives Sur face Mount ing Device (SMD) Requirements . . . . . . . . . 4-58

4-19 Major Types o f P r i n t e d C i r c u i t Boards . . . . . . . . . . . . . . . . 4-60

4-20 P r o p e r t i e s of Screen I n k Systems . . . . . . . . . . . . . . . . . . . 4-61

4-21 Comparison o f Var ious Means of Transmiss ion . . . . . . . . . . . . . 4-65

4-22 S e l e c t e d A p p l i c a t i o n Areas f o r I r r a d i a t e d Polymer M a t e r i a l s . . . . . 4-68

4-23 Comparison o f P h y s i c a l P r o p e r t i e s f o r Convent ional 105' C PVC and I r r a d i a t e d PVC Wire Compounds . . . . . . . . . . . . . . . . . . 4-69

4-24 E f f e c t o f S p e c i f i c G r a v i t y o f a M a t e r i a l on t h e Depth of E l e c t r o n Beam P e n e t r a t i o n a t Two E l e c t r o n A c c e l e r a t o r Vo l tages . . . . 4-70

4-25 Comparison of Chemical V u l c a n i z a t i o n Versus I r r a d i a t i o n P rocess ing . . 4-73

4-26 Rubber Market D i s t r i b u t i o n . . . . . . . . . . . . . . . . . . . . . . 4-75

4-27 A p p l i c a t i o n s f o r R a d i a t i o n Processed E las tomer i c M a t e r i a l s . . . . . . 4-76

4-28 Re1 a t i v e Adhesive Bond S t reng ths f o r Plasma and Convent ional Methods o f T r e a t i n g Polymer Sur faces . . . . . . . . . . . . . . . . . 4-77

4-29 Plasma Coat ings . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-77

5-1 UV and I R Process ing Cost and Energy E f f i c i e n c y Data . . . . . . . . . 5-3

5-2 Comparison o f UV Versus Gas F i r e d Thermal Cure Coa t ing / Ink Systems f o r Beverage Con ta ine rs . . . . . . . . . . . . . . . . . . . . . . . 5-4

Equipment f o r Coa t ing Aluminum C o i l Stock . . . . . . . . . . . . . . 5-5 5-3 Opera t i ng Cost A n a l y s i s f o r R a d i a t i o n Versus Thermal Process ing

.

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Table

5 -4

5-5

5-6

5-7

5-8

5-9

5-10

5-11

5-12

5-13

5-14

5-15

6-1

6-2

6-3

6-4

6-5

6- 6

6- 7

6-8

Comparison o f Energy Requirements f o r D i f f e r e n t Energy Sources on a Model C o i l Coat ing L ine . . . . . . . . . . . . . . . . . . . . . Comparative Cost Ana lys i s f o r High Energy E l e c t r o n Cured Coa t ing Systems Versus Convent ional Thermal ly Cured Coa t ing Systems on Aluminum C o i l Stock . . . . . . . . . . . . . . . . . . . . . . . . . Comparison o f Cur ing Methods. . . . . . . . . . . . . . . . . . . . . Comparison o f Dryer Process ing Costs f o r P r i n t i n g A p p l i c a t i o n s . . . . Comparison o f Annual Opera t i ng Cost, P roduc t i on and Cost Savings Between a Convent ional UV L i n e a r R a d i a t i o n Processor and a Compact On-Mandrel UV Processor . . . . . . . . . . . . . . . . . . . . . . . Cost Savings Comparisons Between Convent ional UV and On-Mandrel UV Processors f o r a P l a n t Rated a t 1.12 B i l l i o n P r i n t e d Cup C a p a c i t y . . P r e l i m i n a r y Cost Comparison f o r Thermal and E l e c t r o n Beam Cur ing o f Adhesi ves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Economics, Photochemical vs . Thermal P roduc t i on L ines Pressure- S e n s i t i v e Adhesive Tape and Labels. . . . . . . . . . . . . . . . . . Energy Comparison, CV and EB, f o r Wire I n s u l a t i o n C r o s s - l i n k i n g . . . Cost Comparison Data ( C V / E B ) . . , . . . . . . . . . . . . . . . . . . Est imated Cost t o Plasma T rea t Small Objects . . . . . . . . . . . . . Est imated Cost t o Plasma T r e a t a Cont inuous Web o f PVC F i l m . . . . . R a d i a t i o n Process ing End Use Markets and Products . . . . . . . . . . Annual Shipment Values f o r t h e I n d u s t r i a l Product F i n i s h i n g ( I P F ) Market; Gross N a t i o n a l Product (GNP) Values and IPF/GNP R a t i o s . . . . A n a l y s i s o f Convent ional and R a d i a t i o n Curable Coat ings f o r Wood F i n i s h i n g Market Areas. . . . . . . . . . . . . . . . . . . . . . . . Ana lys i s o f Convent ional and R a d i a t i o n Curable Coat ings f o r Meta l F i n i s h i n g M ark e t Are as . . . . . . . . . . . . . . . . . . . . . . . . A n a l y s i s o f Convent ional and R a d i a t i o n Curable Coat ings f o r P ac k ag i ng Market Areas . . . . . . . . . . . . . . . . . . . . . . . . Annual Shipment Values f o r P r i n t i n g Inks ; Gross N a t i o n a l Product Values and P I / G N P Ra t ios . . . . . . . . . . . . . . . . . . . . . . . Convent ional and R a d i a t i o n Curable P r i n t i n g I n k I n d u s t r y Market A n a l y s i s . . . . . . . . . . . . . . . . . . . . . . . . . . . H i s t o r i c a l Growth o f S y n t h e t i c and Rubber Adhesives (AD); GNP Val ues and AD/GNP R a t i o s . . . . . . . . . . . . . . . . . . . . . . .

Page

5-7

5-8

5-9

5-11

5-12

5-13

5-14

5-15

5-17

5-18

5-20

5-21

6-2

6-5

6-9

6-11

6-12

6-17

6-18

6-21

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Table Page

6-9 Convent ional and R a d i a t i o n Curable S y n t h e t i c and Rubber Adhesive Market Ana lys i s . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21

6-10 U.S. S y n t h e t i c and N a t u r a l Rubber Consumption. . . . . . . . . . . . . 6-26

6-11 Magnet ic Media Market . . . . . . . . . . . . . . . . . . . . . . . . 6-31

6-12 R a d i a t i o n Process ing o f Polymer ic M a t e r i a l s Markets and Growth P o t e n t i a l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-32

6-13 R a d i a t i o n Process ing Equipment (Growth and Major Market Areas) . . . . 6-33

6-14 U.S. Shipments o f I n d u s t r i a l F i n i s h e s b y Coat ings M a t e r i a l s and S y s t e m s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35

6-15 Energy A n a l y s i s o f Coa t ing Technologies . . . . . . . . . . . . . . . 6-36

Systems f o r Wheel Rims. . . . . . . . . . . . . . . . . . . . . . . . 6-38

System on E l e c t r o g a l v a n i z e d S t e e l . . . . . . . . . . . . . . . . . . 6-40

6-16 Cost Comparison o f E l e c t r o n Beam t o Hot A i r Convect ion Cur ing

6-17 Comparison Between EB Cur ing and Thermal Cur ing Coa t ing

xv i

SU MM A R Y

The a p p l i c a t i o n o f e lec t romagne t i c r a d i a t i o n t o po l ymer i c m a t e r i a l s can l e a d t o t h e f o r m a t i on o f three-d imensional network s t r u c t u r e s , which g e n e r a l l y improve

t h e o v e r a l l p h y s i c a l o r chemical p r o p e r t i e s of t h e o r i g i n a l s u b s t r a t e . This use o f

e l e c t r o m a g n e t i c r a d i a t i o n t o a1 t e r t h e p h y s i c a l and chemical n a t u r e o f a po l ymer i c

m a t e r i a1 i s termed r a d i at ion-processing o r r a d i a t i o n - c u r i n g techno1 ogy. R a d i a t i o n process ing, as a p p l i e d t o c r o s s - l i n k i n g (network f o r m a t i o n ) o f polymer, i n k , adhe-

s i v e , o r c o a t i n g m a t e r i a l s , i n v o l v e s t h e f u l l spectrum of e l e c t r o m a g n e t i c r a d i a t i o n

energ ies t o e f f e c t chemical r e a c t i o n s . These forms o f r a d i a t i o n energy i n c l u d e

i o n i z i n g r a d i a t i o n ( i .e . , a, 6, and y rays from r a d i o a c t i v e n u c l e i ) , X-rays, h igh - -

energy e l e c t r o n s , and n o n i o n i z i n g r a d i a t i o n assoc ia ted w i t h t h e u l t r a v i o l e t ( U V ) , v i s i b l e , i n f r a r e d ( I R ) , microwave, and r a d i o f requency wavelengths o f energy.

R a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s r e q u i r e s t h a t e l e c t r i c a l energy be conver ted t o some fo rm o f e lec t romagne t i c r a d i a t i o n energy w i t h s u f f i c i e n t power o r

i n t e n s i t y t o be commerc ia l l y f e a s i b l e . The most common r a d i a t i o n sources o r equip-

ment f o r t h e commercial c r o s s - l i n k i n g o f po l ymer i c m a t e r i a l s a r e i n f r a r e d lamps , u l t r a v i o l e t l i g h t sources , low- and h igh-energy e l e c t r o n a c c e l e r a t o r s , and plasma

o r g low-d ischarge energy sources. T y p i c a l l y t h e m a t e r i a l t h a t i s processed passes

th rough a d r y i n g area o r oven f o r i r r a d i a t i o n .

R a d i a t i o n p rocess ing o f m a t e r i a l s i s a technology based on t h e f o l l o w i n g :

0 Chemical r e a c t i o n s o f sma l l monomer o r o l igomer components (mo lecu la r weight , ca 100-1,000) t o fprm l a r g e polymer components (molecular weight , ca 1,000-25,000 - i n f i n i t e ) .

0 Small monomer-oligomer components combining t o g e t h e r w i t h l a r g e preformed polymer components.

0 Connect ing l a r g e polymer components t o g e t h e r .

0 Changing t h e s u r f ace c h e m i s t r y o f l a r g e polymer components f o r improved chemical o r p h y s i c a l p r o p e r t i e s

s-1

The o v e r a l l chemis t r y o r chemical r e a c t i o n s o f m a t e r i a l s assoc ia ted w i t h t h i s tech - n o l o g y can be f u r t h e r c l a s s i f i e d as thermal ( conven t iona l ), UV l i g h t - i n d u c e d

(photochemical o r photopolymer i z a t i o n ) , h i g h energy e l e c t r o n , and plasma processes.

R a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s has found widespread commercial use i n

t h e f o l l o w i n g areas:

0 Coat ings 0 P r i n t i ng 0 Adhes i ves 0 Electronics/communications 0 P l a s t i c s and rubber m a t e r i a l s 0 Plasma process ing

The advantages o f r a d i a t i o n p rocess ing polymer techno log ies over those o f conven-

t i o n a l f o s s i l energy-heated p rocess ing techniques i n these areas i n c l u d e :

Rapid d r y i n g speeds (seconds o r l e s s ) .

Reduct ion o r e l i m i n a t i o n o f o rgan ic s o l v e n t s , thus e l i m i n a t i n g a i r p o l l u t i o n and i n c i n e r a t i o n problems.

S i g n i f i c a n t r e d u c t i o n o r e l i m i n a t i o n o f f o s s i l energy-heated d r y i n g ovens and i n c i n e r a t o r s .

Coat ing o f heat-sensi t i ve m a t e r i a1 s ( p l a s t i c s 1.

I nc reased p r o d u c t i o n r a t e s .

More e f f i c i e n t use o f po l ymer i c c o a t i n g m a t e r i a l s because o f l e s s p e n e t r a t i o n o f f l o w i n g m a t e r i a l i n t o s u b s t r a t e s .

Savings i n space o f a p p l i c a t i o n equipment.

Manufacture o f p roduc ts w i t h h i g h value-added p r o p e r t i e s .

Development o f p roduc ts t h a t cannot be manufactured b y any o t h e r p rocess ing technique.

I n t h e U n i t e d S ta tes i t i s es t ima ted t h a t t h e t o t a l use o f r a d i a t i o n p r o c e s s i b l e

m a t e r i a l i s va lued a t app rox ima te l y $0.7 t o $1.1 b i l l i o n and i s expected t o

i n c r e a s e between $1.4 and $1.8 b i l l i o n i n 1990. C u r r e n t l y t h e r e a re approx ima te l y

3035 t o t a l r a d i a t i o n (UV, EB, I R ) p rocess ing u n i t s i n t h e U n i t e d S t a t e s which a re

r a t e d a t a t o t a l ( c u m u l a t i v e ) c a p a c i t y of 430,000 kw. I n 1990 t h e t o t a l number of p rocess ing u n i t s i s expected t o reach 8610 u n i t s f o r a t o t a l r a t e d c a p a c i t y o f

1,500,000 kw.

va lued a t app rox ima te l y $0.3 t o $0.6 and $0.1 t o $0.4 b i l l i o n r e s p e c t i v e l y .

European and Japan es t ima tes f o r r a d i a t i o n p r o c e s s i b l e m a t e r i a l s a re

These

s-2

values should i n c r e a s e t o $0.7 t o $0.95 b i l l i o n (Europe) and $0.8 b i l l i o n (Japan) i n t h e yea r 1990.

app rox ima te l y 2990 u n i t s (500,000 kw t o t a l c a p a c i t y r a t i n g ) and approx ima te l y 1690

u n i t s (300,000 kw t o t a l c a p a c i t y r a t i n g ) a re c u r r e n t l y i n s t a l l e d i n Japan. I n t h e

yea r 1990 t h e number o f u n i t s i s expected t o i nc rease t o 8610 (1,500,000 kw capac-

i t y r a t i n g ) and 2500 (430,000 kw t o t a l c a p a c i t y r a t i n g ) f o r Europe and Japan

r e s p e c t i v e l y .

The t o t a l number o f r a d i a t i o n p rocess ing u n i t s f o r Europe i s

The t o t a l impact o f r a d i a t i o n p rocess ing of po l ymer i c m a t e r i a l s , w h i l e s i g n i f i c a n t , i s s t i l l a minor p a r t o f t h e t o t a l p roduc t manu fac tu r ing techn iques c u r r e n t l y i n

use today. The o v e r a l l annual growth r a t e f o r r a d i a t i o n p rocess ing techniques i s

p r o j e c t e d t o be between 10 t o 20%, thus i t i s an a t t r a c t i v e area f o r f u t u r e r e -

search and development a c t i v i t y . Severa l f u t u r e developments expected f o r t h i s techno logy can be desc r ibed as f o l l o w s :

0 Cont inued research i n h i g h energy phys i cs d i r e c t e d a t e l e c t r o n beam a c c e l e r a t o r s f o r beam p ropaga t ion , maintenance and c o n t r o l .

0 Cont inued research and development i n UV and I R p rocess ing equ i pmen t .

0

0 Development o f new s p e c i a l t y p roduc ts and markets f o r r a d i a t i o n

0 Reduct ion i n m a t e r i a l c o s t s ( l ower c o a t i n g c o s t s ) t o t h e use r

Development o f new r a d i a t i o n s e n s i t i v e po l ymer i c m a t e r i a l s .

p rocess ing techno log ies .

o r p roduc t f i n i s h e r .

The p resen t b e n e f i t s f rom r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s a re d e r i v e d

from improved q u a l i t y , s p e c i a l p r o p e r t i e s and h i g h e r p r o d u c t i v i t y . The advantages

of low-energy consumption and low p o l l u t i o n a re g e n e r a l l y secondary c o n s i d e r a t i o n s

b u t t h i s c o u l d change d r a m a t i c a l l y depending on EPA r u l i n g s and a v a i l a b i l i t y o f

f o s s i l f u e l s u p p l i e s . Increased usage o f r a d i a t i o n p rocess ing of po l ymer i c systems

w i l l depend on m a t e r i a l c o s t s and address ing t h e t e c h n i c a l vo ids p r e v i o u s l y d i s -

cussed above, as w e l l as, t h e e f f e c t s o f compet ing t e c h n o l o g i e s w i t h i n s p e c i f i c

market areas.

ment o f s p e c i a l t y p roduc ts w i l l i n s u r e t h a t r a d i a t i o n p rocess ing t e c h n o l o g i e s w i l l c o n t i n u e t o grow i n impor tance th roughou t t h e wor ld .

However , t h e r a p i d cure, low p rocess ing temperatures , and develop-

s-3

Sec t ion 1

INTRODUCTION

The a p p l i c a t i o n o f e lec t romagne t i c r a d i a t i o n t o po l ymer i c m a t e r i a l s can l e a d t o

t h e f o r m a t i o n o f three-d imensional network s t r u c t u r e s , which g e n e r a l l y improve t h e o v e r a l l p h y s i c a l o r chemical p r o p e r t i e s o f t h e o r i g i n a l s u b s t r a t e . Th is use o f

e l e c t r o m a g n e t i c r a d i a t i o n t o a1 t e r t h e p h y s i c a l and chemical n a t u r e o f a po l ymer i c

m a t e r i a l i s termed r a d i a t i o n - p r o c e s s i n g o r r a d i a t i o n - c u r i n g technology. R a d i a t i o n

process ing, as a p p l i e d t o c r o s s - l i n k i n g (network f o r m a t i o n ) o f polymer, i n k , adhe-

s i v e , o r c o a t i n g m a t e r i a l s , i n v o l v e s t h e f u l l spectrum of e lec t romagne t i c r a d i a t i o n

energ ies t o e f f e c t chemical r e a c t i o n s . i o n i z i n g r a d i a t i o n ( i .e. , a , B , and y rays f rom r a d i o a c t i v e n u c l e i ) , X-rays, h igh--

energy e l e c t r o n s , and n o n i o n i z i n g r a d i a t i o n assoc ia ted w i t h t h e u l t r a v i o l e t ( U V ) ,

v i s i b l e , i n f r a r e d ( I R ) , microwave, and r a d i o f requency wavelengths o f energy (see

Tab le 1-1 and F i g u r e 1-1). (1) -

These forms of r a d i a t i o n energy i n c l u d e

Table 1-1

ELECTROMAGNETIC SPECTRUM (1)

Types o f R a d i a t i o n

Gamma r a y

E l e c t r o n beam

X-ray

U 1 t r a v i ol e t

V i s i b l e

I n f r a r e d

Microwave

Radio Frequency

Wavelengths , nm

1 0 - ~ - 1 0 - ~ 10- 3-1~- 10-2-10 10-400 400-750 750-105 >lo6 >lo6

Frequency, Hz

1019-1~22 1018- 1021 1 0 ~ ~ - 1 0 ~ 9 1 0 ~ ~ - 1 0 ~ ~

1 0 ~ ~ - 1 0 ~ 4 l o l l - 1012 < l o l l

Energy, eV

105-108 104-107 102-105

10-2-1 <lo-2 <lo-2

5-lo2 1-5

I n genera l , r a d i a t i o n p rocess ing ( c u r i n g o r c r o s s - l i n k i n g ) o f po l ymer i c m a t e r i a l s

and t h e r e l a t e d techno log ies i n v o l v e s f o u r main c o n s i d e r a t i o n s :

t i o n and assoc ia ted p rocess ing equipment; t h e n a t u r e of t h e po lymer i c m a t e r i a l s t o

be i r r a d i a t e d and t h e i r response c h a r a c t e r i s t i c s ; mechanisms o r t h e o r i e s o f reac -

t h e t y p e o f r a d i a -

1-1

I ro

Ultra Violet

0.38 0.76 2 4 pm 1 mm I I I I I

Visible Short- Medium Light Wave Wave Long-Wave I.R.

I.R. I.R.

G m " Inf ra-Red X-Rays Ultra Violet L

Rays Rays Rays Radio Waves I 1 nm 1 m 1 mm l m 1 km

Middle I.R. Far I.R. Visible Near Light I.R.

Wavelength /'io-9 10-6 10-3 \ o o 103 m

Temperature of Peak Radiated Energy L O 3000 500 212OF

0.3 0.72 1.5 5.6 8

Figure 1-1. Electromagnetic Spectrum (1)

1,000 pm Wavelength

1 1 I

t i o n ; and chemical , p h y s i c a l and mechanical p r o p e r t i e s r e s u l t i n g f r o m t h e fo rma t ion

o f po l ymer i c network s t r u c t u r e s . ( 2 ) - These v a r i a b l e s a re d iscussed i n t h e s e c t i o n s t h a t f o l l o w . Wi th t h i s as background, a p p l i c a t i o n s and markets as w e l l as s a l e s

p r o j e c t i o n s a re assessed. The r e p o r t concludes w i t h a sumnary o f areas i n which

R&D i n t h e c u r i n g area would h e l p t o advance t h e s t a t e o f t h e a r t .

1-3

Section 2

RADIATION PROCESSING EQUIPMENT

Radiation processing of polymeric materials requires t ha t e l e c t r i c a l energy be converted t o some form of electromagnetic radiat ion energy with su f f i c i en t power or in t ens i ty t o be commercially f eas ib l e . The most common radiat ion sources or equipment fo r the commercial cross-l inking of polymeric materials are infrared lamps , u l t r av io l e t l i gh t sources , low- and high-energy electron accelerators , and plasma or glow-discharge energy sources. Typically the material t ha t i s processed passes

t h r o u g h a drying area or oven fo r i r r ad ia t ion . (3)

I N F R A R E D RADIATION PROCESSING EQUIPMENT

Infrared (IR) radiat ion i s the part of the electromagnetic spectrum having wavelengths between 0.7 and 1,000 microns (Figure 1-11. (3 ,4 ) An important commercial use of infrared radiat ion i s t o thermally drive off solvents or water from an ink or coating system, and t o bring about curing of the ink or coating th rough oxida- t i o n i n a i r or t h r o u g h other forms of thermally act ivated chemical reaction processes. In prac t ice three basic types of IR emitter equipment are available: those tha t produce long-wave (4-1000~) , medium-wave (2-4p) , and short-wave (0.7-2p) IR rad ia t ion . (5,6) - Long-wave IR emit ters generate considerable amounts of heat , b u t tend t o be more d i f f i c u l t t o d i r ec t onto a subs t ra te . T h i s type o f thermal radia- t i o n i s d i f f i c u l t t o r e t a in within the drying (oven) area because the longer wavelengths of IR radiat ion are sca t te red by a i r . There i s more s t r a y heat and l i t t l e penetration capabi l i ty ; i t e s sen t i a l ly causes only surface drying of inks and coatings a t the expense of grea t ly increased dwell times in the processing unit (Figure 2-1) . Medium-wave IR emit ters produce IR i r rad ia t ion tha t penetrates the i n k or coating surface a l l the way through t o the subs t ra te (Figure 2-2) . Short-wave IR emit ters focus IR radiat ion t o a h i g h in tens i ty fo r curing thick f i lms in a very short period of time (Figure 2-3). In contrast t o long-wave IR emi t te rs , short-- wave IR emit ters are very e f f i c i e n t and exhibi t very l i t t l e heat loss t o the sur- rounding oven areas.

One fac to r i n considering the use of IR radiat ion in commercial appl icat ions i s emit ter e f f ic iency . The theore t ica l re la t ionship between a given IR emit ter temperature and maximum in tens i ty wavelength i s shown in Figure 2-4. In prac t ice ,

2-1

I.R. Emitter

J

Substrate \

Figure 2-1. Schematic o f Application o f Long Wave IR Radiation (6)

2-2

I.R. Emitter

Substrate

Figure 2-2. Schematic of Application of Medium Wave IR Radiation (6) -

2-3

I.R. Emitter

F i g u r e 2-3. Schematic of A p p l i c a t i o n of Shor t Wave I R R a d i a t i o n (6)

2-4

0 0 0 cu

0 0 z

2-5

however, an IR emitter exhibi ts a broad d is t r ibu t ion of wavelengths ( c f . Figure 2-51 - where the operating temperature of the emit ter corresponds t o the maximum p o i n t of each d is t r ibu t ion curve. As the emitter temperature decreases, so does the emitted energy from the IR source. described as f o l l ows :

This d r o p off in emitted energy can be

Emitted Energy = (emissivi ty) (constant) (absolute or E = E O T 4

temperature of the

zed by i t s emissiv

4 emi t t e r )

The ef f ic iency of a radiat ing surface i s character t y ( € 1 . An emissivi ty value of 1 re l a t e s t o perfect energy conversion t o electromagnetic waves from the primary energy source (e.g., e l ec t r i ca l res i s tance source, gas- or o i l - - f i r e d source) (Figure 2-6).

Another f ac to r t o consider i s the e f f ec t of emitted energy on the coating or sub- s t r a t e undergoing the radiat ion processing operation. s i v i t y appears t o be d i r ec t ly proportional t o the absorpt ivi ty of the materials being processed a t a par t icu lar wavelength and surface temperature. (Table 2 - 1 ) . Select ive absorption of IR energy by cer ta in ink and coating formulations can also become an important overall curing eff ic iency f ac to r ; short-wave IR radiat ion i s more r e f l ec t ive from surfaces with highly colored or r e f l ec t ive pigments than i s long-wave IR radiat ion (Figure 2 - 7 ) .

Under these conditions emis-

Infrared radiat ion emitter processing equipment can be divided in to two general c lasses : one using gas- or oil-burning units and the other using e l e c t r i c a l energy. Figures 2-8, 2-9, and 2-10 depict common types of IR emit ter systems; Table 2-2 l i s t s the major cha rac t e r i s t i c s associated with e l e c t r i c a l l y activated IR emit ter devices. (3-6)

ULTRAVIOLET ( U V ) LIGHT SOURCES

Ul t rav io le t ( U V ) radiat ion i s the par t of the electromagnetic spectrum having wavelengths from 4 t o 400 nanometers. The basic energy source fo r i n i t i a t i n g react ions of UV responsive mater ia ls is the mercury vapor lamp. The major lamp systems in commercial use today are as follows:

0 Low mercury pressure ( t o r r germicidal 1 amps.

0 Medium pressure (1 t o 2 atmospheres) mercury vapor lamps having electrode configurations f o r operation.

2-6

-I

a 2 4 5

n

(D n

0

v

P 0 0

m 0 0

4 h) 0 0

4 Q, 0 0

lo 0 0 0

h) P 0 0

h) m 0 0

Btu Per Sq. Ft. Per Hour at Various Emissivity Values

4 4 4 4

% 53 5! B I I I I I I I I I I I I I I

I I 1 1 I

Table 2-1

NORMAL TOTAL E M I S S I V I T Y OF VARIOUS SUBSTRATES (5)

Sur f ace

Aluminum, Commercial Sheet

Brass, D u l l P l a t e

Copper, Po l i shed

Gold, Pure, H i g h l y Po l i shed

S tee l , Pol i shed

I r o n , Po l i shed

Oxidized, I ron , Dark-Gray Sur face

S t a i n l e s s S tee l , Po l i shed S t a i n l e s s S tee l , Type 301;B Tin, B r i g h t Tinned I r o n

Tungsten F i 1 ament Zinc, Galvanized Sheet I ron , F a i r l y B r i g h t

Asbestos, Board

B r i c k , F i r e c l a y

Enamel, White Fused, on I r o n

Pa in ts , Lacquers, Varnishes: Snow-white enamel v a r n i s h on rough i r o n p l a t e

Black sh iny lacquer , sprayed on i r o n

Black sh iny s h e l l a c on t i n n e d i r o n sheet

B lack mat te s h e l l a c

Black o r w h i t e lacquer

F1 a t b lack 1 acquer

Roof ing , Paper

Rubber, Hard Glossy P l a t e

Water

T, OF

212 120-660 242

440- 1160 212

800-1880 212 212

450- 1725 76 6000 82 74 1832 66

73 76 70

170-295 100-200 100-200 69 74

32-212

E m i ss i v i t y

0.09 0.22 0.023

0.018-0.035 0.066

0.14-0.38 0.31 0.074

0.54-0.63 0.045 & 0.064

0.39 0.23 0.96 0.75 0.90

0.906 0.875 0.821 0.91

0.80-0.95 0.96-0 e98

0.91 0.94

0.95-0.963

2-9

100

90 -

I\ 80 -

70 -

60 -

50 -

40 -

30 -

20 -

1 2 3 4 5 6 7

Peak Wave Length (microns)

3

F i g u r e 2-7. S e l e c t i v e Absorp t ion o f IR R a d i a t i o n by Var ious Subst ra tes (4) -

2-1 0

Exhaust Gas

Combustion

IR Radiation Emission Fuel /

and Air Inlet

FueVAir Inlet

Impingement Flame

Combustion

f Refractory

Surface

IR Emission

F i g u r e 2-8. Common IR R a d i a t i o n E m i t t e r s - Fuel Burn ing Types (3)

2-1 1

Boro-Silicate Glass Bulb

Tungsten Filament

Electrodes

Ceramic or Quartz Plate Element

Nichrome Wire Coil

Figure 2-9. Common IR Radiation Emitters - Elec t r ica l Types (3)

2-1 2

Source Temperature Normal Max. Usual Range

Brightness

Usual Size

Wavelength at Energy Peak - Normal Max. (Emissivity)

Usual Range N I

P 2

Table 2-2

CHARACTERISTICS OF COMMERCIALLY USED INFRARED HEAT SOURCES ( 3 ) -

Tungsten

Glass Bulb

4000OF 3000 to 40000F

Bright White Heat

6-30 Lamp

1.15 Micron

1.5 to 1.15 Micron

Filament Wire

T3 Quartz Lamp

4000OF 3000 to 4000OF

Bright White Heat

318" di a. Tube

1.15 Micron (0.86)

1.5 to 1.15 Micron

Nichrome Spiral Winding

Quartz Tube Metal Sheath

1600OF 1200OF 1800 to 1400 to 1400OF lOOOOF

Cherry Dull Red Red

3f8 or 5f8" dia. tube dia. tube

2.6 3.1 Micron Micron (0.62) (0.56)

2.6 to 2.8 2.8 to 3.6 Micron Micron

3f8 or 518"

Low Temperature Panel Heaters

Buried Metallic Nichrome Salt --

600-8OOOF

1100-4OOOF

No Visible Light

Flat panels - Various

Around 4-5 Micron

3.2 to 6 Micron

Gas Infrared Burners Perforated Impingement Tile Type Type

1700OF 2200OF

1400-155OOF 1400-205OOF

Soft Red Bright Red

3 x 22 or 5 x 22" 3 x 12"

2.6 2.2 Micron Micron

2.5 to 2.8 2.2 to 2.8 Micron Micron

Relative Energy Distribution Normal Maximum

Radiation 86% 86% 55% 50% 40-30% 54% Convection & Cond. 20% 14% 45% 50% 60-70% 46%

Usual Range Radiation 65-80% 72-86% 5 5 4 5 % 53-45% 50-20% 46-50% Convection & Cond. 32-20% 28-14% 4545% 47-55% 50-80% 54-50%

Degree of Heat Penetration Depth of penetration varies with the characteristics of the product. energy of shorter wavelengths penetrates deeper than energy of longer wavelengths.

As a general rule,

44% 56%

36-40% 64-60%

Relative response to seconds seconds Heatup-Cooldown seconds seconds

minutes minutes score of minutes 1 min to 60% 3 min to 60% seconds minutes scores of minutes 1 min to 18% 7 min to 18%

Color Sensitivity Bodies of different colors can be heated at more nearly the same rate by infrared radiation with long wavelengths than they can by short wavelength infrared radiation.

Ruggedness Mechanical Shock Thermal Shock

poor good good excel 1 ent varies with panel fair poor poor excellent excellent excel lent design - could be excellent fair

quite good

Average life (hrs) 5,000 10,000 10-20,000

: I I I , I

0 Medium pressure mercury vapor lamps a c t i v a t e d b y microwave energy r a d i a t i o n and thus do n o t r e q u i r e e l e c t r o d e s ( e l e c t r o d e - l e s s lamp o p e r a t i o n developed by Fusion Systems C o r p o r a t i o n ) .

0

0 Metal doped o r h y b r i d xenon/mercury vapor lamp systems.

F lash lamps o r pu l sed xenon gas a rcs .

D e s c r i p t i o n o f t h e power s u p p l i e s , t y p i c a l lamp c o n f i g u r a t i o n s , and des ign cons id -

e r a t i o n s f o r low mercury pressure, medium mercury pressure, and f l a s h lamps a re

g i v e n i n F i g u r e s 2-11 and 2-12. General o p e r a t i n g c h a r a c t e r i s t i c s f o r seve ra l o f

t hese lamp systems a re l i s t e d i n Table 2-3. ( 7 ) -

The two major lamp systems having commercial r a d i a t i o n p rocess ing s i g n i f i c a n c e

today are t h e conven t iona l e l e c t r o d e and e l e c t r o d e l e s s (Fus ion Systems C o r p o r a t i o n )

medium p ressu re mercury arcs. A d i r e c t o p e r a t i o n a l c h a r a c t e r i s t i c comparison be-

tween each lamp i s g i v e n i n Table 2-4. (8 ) -

r e f l e c t o r and must be coo led w i t h a i r o r water t o promote e f f i c i e n t lamp o p e r a t i o n

and a reasonable l i f e expectancy. A t y p i c a l l i n e a r a r r a y o f e l e c t r o d e lamps, e l e c -

t r o d e l e s s lamp system, r e f l e c t o r s , and methods o f c o o l i n g i s shown i n F i g u r e 2-13. F u r t h e r developments i n c o o l i n g , gas i n e r t b l a n k e t i n g , f i l t e r i n g o f unwanted excess

i n f r a r e d r a d i a t i o n (which i s always p resen t i n t h e o u t p u t s p e c t r a o f a mercury lamp), and novel lamp housing o r equipment have been p ioneered b y Union Carb ide

Corpo ra t i on . A complete r e v i e w o f l i g h t sources used i n photo-process ing a p p l i c a -

t i o n i s g i v e n i n re fe rences 3 and 7. Examples o f t y p i c a l commercial i n s t a l l a t i o n s

f o r UV r a d i a t i o n p rocess ing equipment a re desc r ibed i n Table 2-5. (9-13)

E i t h e r UV lamp system i s housed i n a

H I G H ENERGY ELECTRON RADIATION PROCESSING EQUIPMENT

Electron-beam processors a re used commerc ia l l y t o c r o s s - l i n k polymers , i n s u l a t i o n s , and w i r e - c a b l e cove r ings , t a k i n g advantage o f t h e i r a b i l i t y t o p e n e t r a t e v e r y t h i c k

c o a t i n g s .

processor are a power supp ly (DC o r RF), a source o f e l e c t r o n s (e.g., a heated w i r e

f i l a m e n t o r r i b b o n ) , a beam a c c e l e r a t i o n system, a vacuum chamber ( l o m 8 t o 10- t o r r ) , o u t p u t windows, and s h i e l d i n g o r housing r e q u i r e d t o c o n t a i n t h e X-rays

generated b y t h e h igh-energy e l e c t r o n s imp ing ing on t h e s u r f a c e e n c l o s i n g t h e e l e c -

t r o n a c c e l e r a t o r ( F i g u r e 2-14). (14) - A c c e l e r a t o r s can be c l a s s i f i e d accord ing

t o t h e i r r a t e d t e r m i n a l v o l t a g e power supp ly requi rements which range i n va lue f rom

0.25-30 MeV. The LINAC a c c e l e r a t o r and seve ra l e l e c t r o s t a t i c a c c e l e r a t o r systems (Van de Graaf , P e l l e t r o n , Ladder t ron ) r e q u i r e v e r y h i g h t e r m i n a l v o l t a g e power

supp ly o p e r a t i n g p o t e n t i a l s (minimum 4 MeV f o r t h e LINAC; between 0.3 t o 30 MeV

f o r e l e c t r o s t a t i c a c c e l e r a t o r s ) . However, these dev ices are n o t n o r m a l l y used f o r

The b a s i c components o r subsystems t h a t make up a h igh-energy e l e c t r o n

6

2-1 5

Thermionic Cathode Lamp

I. Starting Switch - -

Ballast A-C Supply

Power Supply Circuit for a Low Pressure Mercury Arc

Capacitor

Transformer Power Supply for a Medium Pressure Arc

b

R Capacitor e C t i f Lamp i e r

/

Transformer V

Spark Gap

Power Supply for a Flash Lamp

F i g u r e 2-11. UV/Vis L i g h t Source Power Supp l ies ( 7 ) I

2-1 6

e E E O 0 b

e E E

w C

c .- * 5 a

1 m E

f E E d d cv

2-1 7

Lamp Temp.

Lamp Power

Arc Lengths

Bulb Shapes

Re 1 at ive System Costs

Input Power Lamp Warranty

M a j o r Output Wavelengths

Spectral Variations

(“1

Spectral E f f i c i ency

Radiant Efficiency

Overall Efficienty

Practical Limits

Total System Cost

Table 2-3

UV LAMP OPERATING CHARACTERISTICS (E)

Microwave Low Pressure Medium Pressure Energized

Mercury Discharge Mercury Mercury

coo 1 High High

1 - 10 Watts/In. 100 - 400 Watts/In. 300 Watts/In.

10 - 75 Inches 1-1/2 - 77 Inches 10 Inches

Li near, Linear , Curved Linear Circular

Low Moderate High

1 - 10 Watts/In. 110 - 440 Watts/In. 550 Watts/In. 17,500 Hours

254

None

Excel lent

Very Good

Fair

Low Intensity

$200

1,000 Hours

365, 436, 546, 580

Moderate

Good

Good

Good

None

3,000 Hours

365, 636, 546, 580

Extensive

Very Good

Fair

Good

Limited Sizes

Flash Xenon

Moderate (Water Cooled)

.1 to 10 Mega- Watts Peak Power

.6 - 30 Inches Linear , Ci rcu 1 ar , Helical

High

-- 1,000 Hours

450

Limited

Poor

Poor

Poor

Low Efficiency

Under $2,000 $3 to 7,000 $4,000

2-1 8

T a b l e 2-4

LENGTH

POWER -

OPERATIONAL CHARACTER1 S T I CS OF ELECTRODE AND ELECTRODELESS MEDIUM PRESSURE MERCURY ARC LAMP (8) -

- Conventional ' 6" - 7"

100, 200, 300 W/in

Discrete steps

INPUT POWER TO SYSTEM 6600 W, 460/230 V

LIFETIME

Guaranteed 1000 hours

Expected 2000 hours 1000 h r UV output 85%

52% 6000 'I 'I lo 10%

E f f e c t o f s t a r t s No more than 250 i n guarantee

300011 II II

SPECTRAL OUTPUT

Lamp Input 200 W/in output: uv 34

V i s i b l e 56 In f ra red 100 Convected 10

DOPED LAMPS

Avai l a b i 1 i t y Limited Re la t i ve spec t ra l

s h i f t s 10 - 20% Typical l i f e t i m e s 500 - 1000 hrs Length l i m i t a t i o n s Usual ly Ba l l as t changes Usual ly

ON/OFF

Cold s ta r tup t ime 45 sec - 3 min Cool-down r e s t a r t t ime 2 - 10 min o r

45 sec

STANDBY

Power l eve l 50% Shutters Typ ica l l y

COOLING 81 UTILITIES

Pos i t i ve a i r No Negative a i r Yes Water Yes Compressed a i r Yes Nitrogen Yes

REFLECTOR GEOMETRY E l l i p t i c a l and

SPACE REQUIREMENTS

Unfocussed

Height 4 - 6" Width 6 - 10"

E l ectrodel ess

Any length i n modular 10" segments

300 W/in

30-300 W/in stepped o r cont inuously var i ab1 e

5200 W, 240 V

3000 hours

6000 hours 97% 92% 86%

None

300 W/in 97 75 55 73

Unl imited

10 - 100% 1000 - 3000 hrs

None None

2 - 4 sec 10 sec

0 No

Yes No No. No Yes

E l l i p t i c a l and Unf ocussed

12 - 18" 8"

2-1 9

Air (5) H20 H20 ) Air

UV Source: Linear Electrode Lamp (200/300 w/in) Power Supply: 1.5 KV AC > 90% Efficiency Reflector (Parabolic or Elliptical) Energy Profile Cooling (Air, H20) Housing: Radiation Containment Conveyor Bed

Negative Air Cooling

Positive Air Cooling

Radiator (10” long 16” tall

9“ wide) - Exhaust

Power Cable

Ref lector

Controller

Lamp’

Electrodeless Lamp Curing System (Fusion Systems)

Figure 2-13. Commercial UV Processor Units (8)

2-20

Table 2-5

UV CURING EQUIPMENT (9)

UV Curing Device Descriptions

Small (15" maximum); 1 or 2 lamps

Medium (18" and up); multiple lamp systems

Large multichamber UV drying ovens (80" wide to 60' long with as many as 12 rows of lamps)

UV lamps mounted over belts or rollers so that the substrate is cured and stacked

38" wide in-press sheet curing UV systems; narrow and wide continuous web UV curing systems--flex0 and letterpress assemblies (UV lamps can be used 80" in length)

Multiple lamps housing assemblies

End Use Applications

Laboratory and in-plant ink, coating and adhesive test i ng.

Production curing of electronic components; erasing of EPROM computer chips and curing of areas with point source lamps.

Heavy substrates, multiple lamp systems for curing glass, metal and wood: for curing in PC boards and photoresist systems for the electronics industry and multiple lamp systems for paper and plastics (screen, letterpress offset or flexoprinted).

Floor tile, electronics, special textured coatings, abrasion resistant coatings and combinations o f U V - I R for the graphic arts industry on paper, board or glass substrates.

Sheet paper or board stock; screen printing and circuit board manufacture.

Graphics art industry--sheetfed multicolor presses, wet-on-wet printing of UV clear coatings over UV or solvent-based net offset inks--tag and label products and wallpaper or linoleum substrates.

UV curing of three-dimensional objects such as cups, lids, wire, optical fibers, tubes, PC boards containing attached components (compound coatings), partial and fully assembled furniture, tabletops, and s he1 vi ng .

2-21

Power

I

Vacuum U 9 Vacuum

- Shielding

I

Figure 2-14. General Schematic of A High Energy Electron Beam Processing Unit (14)

output Window

2- 22

I output Window

r a d i a t i o n process ing o f polymer m a t e r i a l s . I n d u s t r i a l machines hav ing t e r m i n a l

v o l t a g e power supp ly energy ranges between 0.3 t o 4 MeV a re t y p i c a l l y rep resen ted b y t h e insulated-core-transformer ( ICT) and t h e Dynamitron ( F i g u r e 2-15). Conven-

t i o n a l l y bo th machines operate w i t h a maximum l i n e a r c u r r e n t d e n s i t y o f about 50

mA/m; t h e energy convers ion e f f i c i e n c y f o r e i t h e r d e v i c e i s about 70% w i t h t h e o v e r a l l system e f f i c i e n c y be ing about 40 t o 50%. Both t h e Dynamitron and t h e ICT

power s u p p l i e s can be u t i l i z e d i n a scanned beam c o n f i g u r a t i o n as shown i n F i g u r e

2-16. I n a scanned beam c o n f i g u r a t i o n t h e power supp ly i nc reases and r e c t i f i e s t h e

1 i ne c u r r e n t and t h e a c c e l e r a t o r tube generates and focuses t h e beam ( app rox ima te l y

1 cm i n diameter a t t h e window) and c o n t r o l s t h e e l e c t r o n scanning process. The .

beam i s produced when h i g h v o l t a g e energ izes a tungs ten f i l a m e n t t h e r e b y caus ing

e l e c t r o n s t o be produced a t v e r y h i g h r a t e s . These f a s t e l e c t r o n s a r e concen t ra ted t o fo rm a h igh-energy beam and are acce le ra ted t o f u l l v e l o c i t y i n s i d e t h e e l e c t r o n

gun. Electromagnets on t h e s ides o f t h e a c c e l e r a t o r tube a l l o w d e f l e c t i o n o r scan- n i n g o f t h e beam as i n a t e l e v i s i o n tube. Scanning w id ths and depths v a r y f r o m

61-183 cm t o 10-15 cm, r e s p e c t i v e l y . The scanner opening i s covered w i t h a t h i n meta l f o i l , u s u a l l y t i t a n i u m , t h a t a l l ows passage o f e l e c t r o n s b u t m a i n t a i n s t h e

h i g h vacuum r e q u i r e d f o r h i g h f r e e - p a t h l e n g t h s . C h a r a c t e r i s t i c power, c u r r e n t , and dose r a t e s o f a c c e l e r a t o r s are 200-500 kV, 25-200 mA, and 10-100 kGy/s (1-10

Mrad/s ) . (15-17

High v o l t a g e scanned e l e c t r o n processors have seve ra l d isadvantages. The most

severe of these i s t h e l a r g e areas which must be sh ie lded .

t h e e l e c t r o n a c c e l e r a t o r scanner ac ts as a source o f X-rays generated b y e l e c t r o n s

which a re s c a t t e r e d t o t h e w a l l , and these emissions are a long t h e e n t i r e l e n g t h o f

t h e system.

equipment. (18 ) -

Any s u r f a c e e n c l o s i n g

Another d isadvantage i s t h e l a r g e space requi rement f o r housing t h e

I n a l i n e a r o r p l a n a r cathode system (developed by Energy Sciences) t h e t e r m i n a l

energy requi rements a re about 150 t o 300 kV b u t t h e beam area can be 1000 cm and t h e l i n e a r c u r r e n t d e n s i t y can be as g r e a t as 260 mA/m.

cathode processor i s through a h i g h - v o l t a g e (150 kV) e l e c t r o n tube t h a t p rov ides a

con t inuous s t r i p o f e n e r g e t i c e l e c t r o n s f rom a l i n e a r f i l a m e n t o r cathode, which i s on t h e a x i s o f symmetry o f t h e system. The c y l i n d r i c a l e l e c t r o n gun shapes and

processes t h e e l e c t r o n system i n a g r i d - c o n t r o l l e d s t r u c t u r e . The stream i s then

a c c e l e r a t e d across a vacuum gap t o a meta l window where i t emerges d i r e c t l y i n t o

a i r and t r a v e l s on to t h e p roduc t .

i s c l a d d i r e c t l y t o t h e tube housing.

s h i e l d e d tube 25 cm i n d iameter rep laces t h e 3-m h i g h s t r u c t u r e r e q u i r e d f o r t h e

2

Operat ion o f a l i n e a r

I n t h i s t y p e of l i n e a r processor , t h e s h i e l d i n g

Housing space i s r e l a t i v e l y sma l l , s i n c e a

2-23

30

20

10 9 8 7 6 5 4

3

2

MeV

1 0.9

0.7 0.6 0.5

0.4

0.3

0.8

0.2

0.1

L I N A C E

L E C T R 0 S T A T I C

D Y N A M I T R 0 N

00 Cathode

I C T

I High Potential 2 Medium Potential 1 Low Potential 1 Accelerators

Figure 2-1 5. H i gh and Low Energy El ectron Processor Power Suppl i e s (1 5,16,17)

2- 24

Shielding

I I

I - I

1 ' 1 1

Electron Gun

Filament

/

/

Acceleration ' Section

Scanning Coils

Vacuum

Scanning Housing

I I

Metal Foil Window I \ \

\ 1 \

I ' I

I I

' t

Figure 2-1 6 . Scanned Electron Beam Accelerator System (E)

2-25

scanned electron-beam apparatus. The e l e c t r o c u r t a i n has a more f l e x i b l e geometry

and can be adapted r e a d i l y t o many d i f f e r e n t types o f c u r i n g a p p l i c a t i o n s ( F i g u r e

2-17). (19 ) - Another des ign f e a t u r e o f t h e p l a n a r cathode processor i s t h e a b i l i t y

t o combine two a c c e l e r a t i o n s e c t i o n s w i t h one o r two separate power s u p p l i e s f o r i nc reased beam i n t e n s i t y values i n t h e range o f 400 mA/m ( F i g u r e 2-18). (20) A d i f f e r e n t t ype o f m u l t i p l e p l a n a r cathode processor has been developed by

R a d i a t i o n Polymer Corpo ra t i on . I n t h i s equipment t h e cathode s t r u c t u r e i s com-

p l e t e l y modular such t h a t i t s l e n g t h can be e a s i l y i nc reased t o accommodate t h e

s i z e requi rements o f a p roduc t l i n e w h i l e m a i n t a i n i n g i t s w i d t h p r o p o r t i o n con- s t r a i n t s i n o rde r t o meet t h e machine 's requi rements f o r an acceptable window c u r -

r e n t d e n s i t y p r o f i l e .

c o n s i s t i n g o f a s e r i e s o f modular t r i o d e s arranged i n a l i n e a r a r r a y as shown i n

F i g u r e 2-19.

The cathode s t r u c t u r e i s a "screen" tube t y p e c o n s t r u c t i o n

T h i s modular cathode c o n s t r u c t i o n a l l ows f o r broad-beam (250 cm wide) p rocess ing

of m a t e r i a l s w i t h powers o f 30 kGy ( 3 Mrad) a t 300 m/min. and l i n e a r c u r r e n t dens-

i t i e s o f 262 mA/m. The system a l s o i n c l u d e s i n t e g r a t e d s h i e l d i n g c a p a b i l i t i e s

s i m i l a r t o those desc r ibed f o r Energy Sc ience ' s p l a n a r cathode equipment. ( 2 1 ) -

A h i s t o r i c a l growth r e p r e s e n t a t i o n f o r h i g h energy p rocess ing equipment development

and u t i l i z a t i o n i s shown i n F i g u r e 2-20 and a g e n e r a l i z e d comparison between swept

beam and p l a n a r cathode h i g h energy e l e c t r o n p rocess ing equipment i s desc r ibed i n

F i g u r e 2-21 and Table 2-6. (22)

Table 2-6

COMPARISONS BETWEEN PLANAR CATHODE AND SWEPT BEAM H I G H ENERGY ELECTRON PROCESSING EQUIPMENT (18,21,22 1

Scan System

Beam Shape

Energy Dose Rate

C om p ac t S i z e

S h ie1 d i n g

Housing Vol ume

C m p l e x i t y

Opera t i ng Vo l tage

Pen e t r a t i on

P lanar Cathode

No

Rec t angu 1 a r

Low

Yes

Less

Less

Less 200 KeV

10 m i l s

Swept Beam

Yes

Swept spo t High

No

Greater

Greater Grea te r

200 KeV-1 MeV

200 m i l s

2- 26

High Voltage Power Supply I L

Vacuum \ : Structure Terminal Chamber

Electron Gun

~

\ Metallic Foil Window

(Anode)

Figure 2-17. Energy Science Planar Cathode Electron Curtain Processor (18,19)

2-27

.. .. C C b

CI

v El c, S W

E. *r 3 0- W

E W

S 0 L c, u W

W

W S 0 N

cn S

m v) W u 0 L

-0 a, -0 E W c, x w

m

7

.r

a

a3 I

N

W L 3 cn LL

- .r

2- 28

Figure 2-19. Processor (21)

Radiation Polymer Corporation's Modular Planar Cathode

2-29

-n a c 5 rD

a.

Beam Current (mA/m)

N I w 0

N I N 0

h) 0

0 P VI ln4atoo 0 0 0 0 0 0 0 0

h) 0 0

0 P U I 0 0 0 0 0 0

I

Where: A = Area of Beam W = Width of Product

= Effective Width of Cure Zone V = Velocity of Traversal of Cure Zone

Figure 2-21 . Processing Units (21,22)

Comparison Between Planar Cathode and Swept Electron Beam

2-31

PLASMA

P 1 asma

therma

T herma


r a d i a t i o n sources i n commercial a p p l i c a t i o n s f a l l i n t o t h r e e c a t e g o r i e s

, co ld , and h y b r i d plasma systems. (23)

plasmas a re produced by gas arcs under atmospher ic p ressu re i n t h e r e g

5,000 t o 50,000 K. The k i n e t i c energ ies o f t h e a r c ' s gas molecules, i o n s , and

on

e l e c t r o n s a re i n e q u i l i b r i u m c o n d i t i o n s . A d i scha rge i s produced t h a t r e q u i r e s a

h i g h v o l t a g e between f i x e d e l e c t r o d e s f o r i n i t i a t i o n b u t t h a t can be ma in ta ined

( a f t e r t h e i n i t i a t i o n process) a t low vo l tages b y a power supp ly w i t h low i n t e r n a l

r e s i stance . Cold plasmas a re produced b y glow d ischarges, such as those found i n neon s igns .

The gaseous i o n s and n e u t r a l gas molecules have temperature ranges between ambient

and a few hundred degrees, whereas t h e e l e c t r o n s have v e r y h i g h temperature va lues

and are n o t under thermal e q u i l i b r i u m c o n d i t i o n s . A d i scha rge t h a t i s produced

i n a gas such as argon a t low pressures (1 mm Hg) can be sus ta ined w i t h as l i t t l e

as 300 V w i t h no l o s s i n e f f i c i e n c y f o r e f f e c t i n g polymer s u r f a c e - t r e a t m e n t m o d i f i -

c a t i o n s o r p roduc ing c o a t i n g s on t h e su r faces o f meta l or nonmetal s u b s t r a t e mate-

r i a l s . The power supp ly f o r t h i s t y p e o f plasma can be designed around dc, low

f requency, rad io - f requency , o r microwave- f requency genera to r systems; t h e equip-

ment used i n t h i s technology i s e i t h e r e x t e r n a l l y coupled ( c a p a c i t i v e l y o r induc-

t i v e l y ) o r i n t e r n a l l y coupled ( c a p a c i t i v e l y o r r e s i s t i v e l y ) as desc r ibed i n F i g u r e s

2-22 and 2-23. I n t h e e x t e r n a l l y coupled apparatus a c o i l , or two p a r a l l e l p l a t e

e l e c t r o d e s , a re p laced around t h e o u t s i d e o f t h e q u a r t z o r g lass vacuum chamber. A

glow d i scha rge i s formed i n s i d e t h e chamber when rad io- f requency power i s a p p l i e d

t o t h e c o i l o r e x t e r n a l e l e c t r o d e s . The advantage o f t h i s system over t h e i n t e r n a l e l e c t r o d e system i s t h a t con tamina t ion o f t h e processed p roduc t b y e l e c t r o d e degra-

d a t i o n i s avoided. (24,251

I n l a r g e - s c a l e commercial a p p l i c a t i o n s o f plasma p rocess ing techno logy i t i s o f t e n

r e q u i r e d t o t r e a t o r coa t sheet m a t e r i a l s i n t h e fo rm of a cont inuous web. The

s u p p l y and take-up r e e l s f o r t h i s process can be o u t s i d e o f t h e plasma p rocess ing

chamber as shown i n F i g u r e 2-24. I t i s a l s o p o s s i b l e t o have b o t h r e e l s i n s i d e t h e

vacuum chamber as shown i n F i g u r e 2-25. The r e l a t i v e economics f o r p rocess ing

m a t e r i a l s i n a plasma apparatus w i l l be d iscussed l a t e r . (26-1

The t h i r d t y p e o f plasma, h y b r i d plasma, i s between c o l d and thermal plasmas and i s

d e f i n e d as hav ing numerous smal l thermal sparks , u n i f o r m l y d i s t r i b u t e d throughout

l a r g e volumes o f non ion i zed gas molecules, t hus p roduc ing a r e l a t i v e l y low average

2-32

Reactor Diagram

Reactor RF Coil

Leak Valve

To Argon Purge

Trap System

I

Roughing

++ Valves

I F 0 Ring Joint P Pressure Gauge

Diffusion Pump

Figure 2-22. Tubular Reactor for P1 asma Polymerization (24,25)

2-33

a

2-34

Treatment Gas or RF Power Supply Monomer Supply

Matching Network

Flow Transducer

Supply Reel Take-U p-Reel

Figure 2-24. Air-to-Air Plasma Processing System (26) -

2-35

Figure 2-25. Take-up Rolls w i t h i n the Vacuum Chamber

Example o f Plasma Processing w i t h Supply and

2-36

temperature of the plasma s t a t e . t h i s type o f plasma, which is produced by a high impedance power supply or electrode arrangement. High voltages are required t o maintain i t s discharge charac- t e r i s t i c s (60-10,000 Hz a t several thousand v o l t s ) . These types of plasmas are most often used t o surface t r e a t p l a s t i c f i lms and par ts fo r improved adhesive bonding or improved p r i n t a b i l i t y (pr in t ing ink r ecep t iv i ty ) . (27-1

Corona and ozone generators are associated with

2-37

Sec t ion 3

RADIATION PROCESSING CHEMISTRY AND MATERIALS

R a d i a t i o n p rocess ing o f m a t e r i a l s i s a technology based on t h e f o l l o w i n g :

0 Chemical r e a c t i o n s o f smal 1 monomer o r o l igomer components (molecular weight , ca 100-1,000) t o form l a r g e polymer components (mo lecu la r weight , ca 1,000-25,000 - i n f i n i t e ) .

preformed polymer components. 0 Small monomer-oligomer components combining t o g e t h e r w i t h l a r g e

0 Connect ing l a r g e polymer components toge the r .

0 Changing t h e s u r f a c e c h e m i s t r y o f l a r g e polymer components f o r improved chemical o r p h y s i c a l p r o p e r t i e s ( F i g u r e 3-1).

The o v e r a l

no logy can

( photochem

processes.

chemi s t r y

be f u r t h e r

c a l o r pho

(28)

o r chemical r e a c t i o n s o f m a t e r i a l s assoc ia ted w i t h t h i s tech -

c l a s s i f i e d as thermal ( conven t iona l ) , UV l i g h t - i n d u c e d

o p o l y m e r i z a t i o n ) , h i g h energy e l e c t r o n , and plasma

THERMAL RADIATION PROCESSING CHEMISTRY

The major commercial uses o f thermal r a d i a t i o n processes a re s o l v e n t removal ( c o a t -

i n g s , i n k s , and adhesive a p p l i c a t i o n s ) and t h e e f f e c t i n g o f chemical r e a c t i o n s

between o l igomers ( m u l t i f u n c t i o n a l low mo lecu la r weight prepolymers o r c ross -

l i n k i n g mo lecu les ) and preformed s o l v e n t - s o l u b l e o r d i s p e r s i b l e h i g h mo lecu la r

we igh t polymers i n o r d e r t o c r e a t e three-d imensional network s t r u c t u r e s . The chem-

i c a l and p h y s i c a l p r o p e r t y response c a p a b i l i t i e s o f cured f i l m s o r s t r u c t u r e s a re

improved over those o f t h e o r i g i n a l m a t e r i a l s b e f o r e t h e thermal p rocess ing

o p e r a t i on. (2) X - polymer

thermal energy

groups 01 i gomer

- Polymer

I *cross-linking

5. s i tes

X - polymer

sol vent

3- 1

I 'I

polymer

M

M

M O O

M O -P

R A D I A T

N

P R 0 C E S S

M = Monomer (mol wt, Ca 100-500) 0 = Oligomer (mol wt, Ca 200-1000) P = Polymer (mol wt, Ca 1,000-Infinite) x = Functional Group

W P Linear Polymer

Crosslinked Three- Dimensional Network

Structure (Cured)

x x x

-P

Figure 3-1. Radiation Processing Chemistry (28)

3- 2

I n some a p p l i c a t i o n s (e.g., w i r e and c a b l e i n s u l a t i o n ) , a preformed polymer, rubber , o r e lastomer can be c r o s s - l i n k e d d i r e c t l y w i t h pe rox ides o r v u l c a n i z i n g

agents as w e l l as combinat ions o f perox ides w i t h m u l t i f u n c t i o n a l r e a c t i v e o l i g o -

m e r i c m a t e r i a l s t o fo rm c r o s s - l i n k e d polymer network s t r u c t u r e s . (1,291 - polymer

- polymer +

Convent ional thermal

---I-* g + peroxide

peroxide + cross-1 ink ing 01 i gomer cross-1 inked

network s t ructure

p rocess ing w i t h I R r a d i a t i o n i s m a i n l y i n v o l v e d w i t h thermo-

f o r m i n g o r heat-bonding o f t h e r m o p l a s t i c po l ymer i c m a t e r i a l s . These polymer heat- -

f o r m i n g o r m e l t i n g processes u s u a l l y do n o t c u r e t h e polymer b u t o n l y cause p h y s i -

c a l changes and m a i n t a i n t h e o r i g i n a l polymer t h e r m o p l a s t i c c h a r a c t e r i s t i c s .

I n o rde r t o cure, i .e., f o rm three-d imensional network s t r u c t u r e s th rough chemical

changes, w i t h I R r a d i a t i o n , i t i s necessary t o des ign a r e a c t i v e f u n c t i o n a l i t y

w i t h i n t h e polymer s t r u c t u r e so t h a t c o u p l i n g r e a c t i o n s can t a k e p l a c e between

polymer chains.

-rpolymerT c=o CHOH I I

I

c =o CH\ h e a t 0 I y 2 i r r a d i a t i o n

0 7H2 I

polymer

OH I CH ‘2

r A c i d f u n c t i o n a l Epoxy f u n c t i o n a l CHOH group group

c ross - 1 i n ked polymer

C e r t a i n po l ymer i c s t r u c t u r e s can a l s o be blended w i t h o t h e r c o r e a c t i v e polymers o r

m u l t i f u n c t i o n a l r e a c t i v e o l igomers t h a t e f f e c t c u r i n g r e a c t i o n s when exposed t o I R r a d i a t i o n . These c o r e a c t i v e polymers and c r o s s - l i n k i n g o l i gomers undergo condensa-

t i o n o r a d d i t i o n , which cause network f o r m a t i o n (Table 3-1). (30-32)

3-3

Table 3-1

INFRARED OR THERMAL RADIATION PROCESSING CHEMISTRY (30,31)

Monomer, 01 i gomer,

Me1 ami ne 01 igomers and hydroxyl -functional polymers

or Pol m e r

Styrene monomer and unsaturated polyesters with peroxides

Epoxy polymers and acid or amine functional 01 igomers or pol ymer s

B1 ocked isocyanates and hydroxyl -functional pol ymer s

Air, metal catalysts and unsaturated oil modified polyesters

Peroxide pol yet hy process)

Peroxide tional v ol i gomer

crossl inking of ene (direct

plus mu1 ti func- nyl unsaturated and polyethylene

Reaction Mechani sm

Transetherification of the melamine with the polymer to form crossl inked polymer network structures

Thermal destruction o f the peroxide to produce free radical intermediates which initiate the polymerization o f styrene with the unsaturated polyester

Acid or amine addition to the epoxy ring followed by ring opening and polymerization into three-dimensional network structures

Unblocking of the isocyanate followed by NCO addition to the polymer hydroxyl group and curing

Air drying or air oxidation to form crosslinked films

Radical induced hydrogen abstraction reactions leading to polymer chain connections and crossl inking

Radical formation, addition propagation and hydrogen abstraction reactions to form crossl inked polymer structures

3-4

UV-VISIBLE LIGHT PROCESSING CHEMISTRY

The t rea tmen t o f po l ymer i c u l t r a v i o l e t ( U V ) o r v i s i b l e l i g h t r a d i a t i o n f a l l s i n t o

two c lasses : 100% r e a c t i v e l i q u i d systems ( c o a t i n g s , i n k s , adhesives) and photo-

s e n s i t i v e preformed polymer s t r u c t u r e s .

i s t i c s o f UV and v i s i b l e - l i g h t energy i r r a d i a t i o n o r p h o t o c u r i n g o f l i q u i d photo-

polymer systems. (33)

I n t h i s c o n t e x t t h e r e a re f i v e c h a r a c t e r -

0 A s t a b l e l i g h t source i s r e q u i r e d , capable o f p roduc ing UV and v i s i b l e wavelengths o f l i g h t , i.e., near and f a r UV, 200-400 nm t o v i s i b l e , 400-700 nm, w i t h s u f f i c i e n t power o r i n t e n s i t y t o be commerc ia l l y f e a s i b l e . (1)

v i s i b l e - l i g h t r a d i a t i o n a t a p p r o p r i a t e wavelengths o f energy as e m i t t e d f r o m t h e l i g h t source (Table 3-21. (34) -

through t h e a c t i o n of l i g h t a b s o r p t i o n b y t h e pho tochemica l l y a c t i v e p h o t o i n i t i a t o r . The f r e e r a d i c a l s i n i t i a t e po l ymer i za - t i o n o f unsa tu ra ted monomers , o l igomers , and polymers; t h e pho tochemica l l y l i b e r a t e d a c i d i n t e r m e d i a t e s i n i t i a t e c a t i o n i c o r r i n g opening p o l y m e r i z a t i o n r e a c t i o n s o f epoxy f u n c t i o n a l monomers, 01 igomers, and polymers.

Unsaturated , h i g h b o i 1 i ng a c r y l i c o r me thac ry l i c monomers , ol igomers, c r o s s - l i n k i n g agents , and low mo lecu la r we igh t p o l y - mers comprise t h e f l u i d , low v i s c o s i t y , l i g h t - c u r a b l e c o a t i n g system and a re analogous t o t h e c o a t i n g m a t e r i a l s used i n the rma l c u r i n g processes. Low mo lecu la r we igh t and h i g h molec- u l a r weight epoxy r e s i n s ( c a t i o n i c c u r i n g mechanism) would a l s o be f o r m u l a t e d i n a s i m i l a r manner as t h e unsa tu ra ted m a t e r i a l s ( f r e e r a d i c a l c u r i n g mechanisms) (Table 3 - 3 ) . (33)

e Free r a d i c a l i n i t i a t i o n o r c a t i o n i c r i n g opening r e a c t i o n s o f t h e r e a c t i v e l i q u i d system and p ropaga t ion i n t o a f u l l y cured, c r o s s - l i n k e d s o l i d c o a t i n g o r f i l m . (35) -

0 A p h o t o i n i t i a t o r i s r e q u i r e d , capable o f absorb ing UV and

0 A c t i v e f r e e r a d i c a l s o r a c i d i n t e r m e d i a t e s must be produced

e

The mechanism o f c a t i o n i c c u r i n g and f r e e r a d i c a l c u r i n g i s o u t l i n e d as f o l l o w s .

F ree Rad ica l Pho tocu r ing System

U V - V i s p h o t o i n i t i a t o r (PI) 7> PI. l i g h t energy f ree rad i ca l intermediate

i PI. +

mu1 t i func t iona l unsaturated monomers and polymers x

three dimensional network s t ruc tu re

3- 5

Table 3-2

PHOTOINITIATORS USED IN ULTRAVIOLET RADIATION CURABLE POLYMERIC MATERIALS (34)

Free Radical Photoinitiators Cationic Photoini ti ators

0 Alkyl ethers of benzoin 0 Diazonium salts of Lewis acids

0 Benzil ketals 0 Aryl iodonium salts of Lewis acids

0 Acetophenone derivatives 0 Aryl sulfonium salts of Lewis acids

0 Ketone-amine combinations

0 Halogenated compounds

Table 3-3

MATERIALS USED IN RADIATION (UV AND EB) CURABLE COATINGS (a)

Free Radical Curinq Mechanisms

0 Single-functional vinyl monomers 2-ethyl hexyl acrylate, styrene, N-vinyl- pyrrol idinone, vinyltoluene, lauryl methacryl ate

0 Multifunctional vinyl monomers 1-6-hexanediol diacrylate, tetraethylene glycol diacryl ate, trimethylolpropane triacryl ate, pentaerythri to1 triacrylate

mal ei c- f umar i c acid unsaturated pol yes ters , acrylic copolymers containing pendant vinyl unsaturation, epoxy acrylates, polyurethane acrylates

0 Unsaturated polymers

Cationic Curinq Mechanisms

0 Single- functional monomers

0 Mu1 ti functional epoxide monomers

vinyl methyl ether, lauryl epoxide

diepoxides or triepoxides phenolic and polyhydroxy a1 coho1 compounds

3-6

C a t i o n i c Pho tocu r ing System

UV-Vis PI -> a c i d 1 I gh t energy

a c i d + L A - mu1 t i f u n c t i o n a l epoxy polymers

three dimensional network s t r u c t u r e s

I n preformed polymer systems t h e d i r e c t a b s o r p t i o n o f UV o r v i s i b l e l i g h t causes

t h e polymer s u b s t r a t e s t o undergo c h a i n s c i s s i o n ( d e g r a d a t i o n ) and c r o s s - l i n k i n g .

C r o s s - l i n k i n g o r c u r i n g o f preformed po lymer i c m a t e r i a l s (e.g., t h e r m o p l a s t i c s ) can

be markedly enhanced through use o f s p e c i a l p h o t o s e n s i t i v e molecules t h a t a r e mixed

i n t o t h e polymer m a t r i x o r t h a t c h e m i c a l l y a t t a c h t o t h e backbone o f t h e polymer

chains. These s p e c i a l p h o t o s e n s i t i v e molecules absorb UV o r v i s i b l e l i g h t ene rg ies

much more e f f i c i e n t l y t han t h e polymer; t h e y r a p i d l y fo rm e x c i t e d s t a t e s which

undergo photochemical r e a c t i o n s , which i n t u r n fo rm r e a c t i v e f r e e - r a d i c a l in termed-

i a t e s t h a t e f f e c t polymer d i m e r i z a t i o n o r c r o s s - l i n k i n g . These s p e c i a l pho tosens i -

t i v e molecules, when compounded i n t o t h e preformed polymer m a t r i x , can undergo

l i g h t - i n d u c e d r a d i c a l a b s t r a c t i o n o r i n s e r t i o n r e a c t i o n s which r e s u l t i n c o u p l i n g

o f t h e polymer cha ins and network f o r m a t i o n . (36) 0 II r

polymer-CH2-polymer t db45J- be n zo p h en on e

( phot osens i t i ve mol ecu 1 e 1

P ol ymer - CH - po 1 ymer t

hv polymer-CH = CH-polymer t N3RN3

b i s a z i de

OH I r- 6 ‘B - degraded and c ross -

1 i n ked polymers

polymer, /polymer C HN HRN HC H

, CHH ( p h o t o s e n s i t i v e mo lecu le ) polymer ‘ k p o 1 ymer

c o u p l i n g r e a c t i o n s

.

3-7

S i m i l a r types o f c r o s s - l i n k i n g r e a c t i o n s a re observed f o r polymers t o which photo-

s e n s i t i v e molecules a r e c h e m i c a l l y a t tached.

polymer-r 0 polymerI 0

I o =CC H =CH -@J

O=CCH=CH +?jJ hv

___3

I 1

po 1 ymer P polymer c o n t a i n i n g photosens

c innamic e s t e r l i n k a g e

R a d i a t i o n c u r i n g o f polymers w i t h

i n photoimaging and p h o t o r e s i s t t

polymer

t i v e c ross -1 i nked polymer

UV and v i s i b l e - l i g h t energ ies i s used w i d e l y

chno log ies (Table 3-4). ( 3 7 ) -

HIGH ENERGY ELECTRON PROCESSING CHEMISTRY

I n t h i s techno logy e l e c t r o n energ ies o f 100 eV o r l e s s a re used t o break chemical

bonds d i r e c t l y , e n a b l i n g f o r m a t i o n o f f r e e r a d i c a l i n t e r m e d i a t e s t h a t cause p o l y -

m e r i z a t i o n i n i t i a t i o n o r polymer c r o s s - l i n k i n g r e a c t i o n s . I n l i q u i d r e a c t i v e p o l y -

mer systems t h e low mo lecu la r we igh t v i n y l unsa tu ra ted monomers, o l i gomers , and

polymers a r e conver ted d i r e c t l y i n t o cured o r c r o s s - l i n k e d f i l m s t r u c t u r e s . (43)

h i g h energy unsa tu ra ted monomers, o l igomers, polymers > i o n i c and - growing

f r e e r a d i c a l polymer i n t e r m e d i a t e s r a d i c a l s

I c r o s s - l i n k e d polymer s t r u c t u r e s

R a d i a t i o n c u r i n g o f preformed polymers w i t h h igh-energy e l e c t r o n i o n i z i n g - r a d i a t i o n

p rocess ing equipment can r e s u l t i n chemical changes t h a t a re assoc ia ted w i t h

c r o s s - l i n k i n g and degrada t ion r e a c t i o n mechanisms. mechanisms on preformed polymer s u b s t r a t e s u s u a l l y i n v o l v e removal o f hydrogen

atoms t o f o r m a macro rad ica l i n t e r m e d i a t e . Macro rad ica l i n t e r m e d i a t e s can then

molecule. Th is c o u p l i n g r e s u l t s i n an i n c r e a s e i n t h e

a r we igh t o f t h e s t a r t i n g polymer.

C r o s s - l i n k i n g r e a c t i o n

coup

o r i g

e t o fo rm a s i n g l e

n a l average molecu

3-8

Table 3-4

PHOTOCURABLE POLYMER SYSTEMS

Polymers Remarks References

poly(viny1 cinnamate) uv- and visible light-induced photodimeriza- 38 tion reactions; used in negative photoresist technologies

polychalcones photodimerization or addition reactions; 39 used in negative photoresist technologies

polysti 1 benes photodimerization or addition reactions; 40 used in negative photoresist technologies

cyclized rubber cross-linked with bis-azide-nitrene insertion 41 reactions

phenolic polymers and diazide photosensitizers for 1 ight-induced 42 acid functional acrylic resins

hydrophobic-hydrophi 1 ic reactions associated with positive photoresist technology

3-9

+cross-link site

If irradiation continues, the original polymer substrate is transformed into one gigantic molecule of infinite molecular weight with lower solvent solubility, higher melting point, and improved physical properties over the original material. Enhancement of cross-linking can be facilitated through the use of multifunctional vinyl monomers or oligomers which copolymerize and propagate much more rapidly than in a direct coupling reaction to form greater amounts of gel or cross-linked materials at lower dose rates and shorter reaction times.

ioni zing

radiation polymer + (CH2=CHln - R rapid gel formation

(multifunctional vinyl monomers or oligomers)

Radiation-induced degradation reactions are in direct opposition to cross-linking or curing processes , de c r e as es bec a u s e of broken ends. (44) -

in that the average molecular weight of the preformed polymer chain scission and without any subsequent recombination of its

ionizing radiation polymer - polymer polymer t polymer (high mol ecul ar weight ) (low molecular weight) (low molecular weight)

In order for efficient radiation curing of a polymer to take place, these degradation processes must be minimized in favor of the desired cross-linking reaction.

THIOL CURING CHEMISTRY

A somewhat different cross-linking chemistry has been developed by W . R. Grace & Co. This technology involves the free radical addition of a thiol (mercaptan) to an olefinic double bond:

3-1 0

photoinitiator

R-S' + H' high energy electrons

peroxides free radical intermediates

free radical initiators

R S ' + C H ~ = CHR I - R S C H ~ - ~ H R I

R S C H ~ - ~ H R I + H * - R S C H ~ C H ~ R I

When a polyene and a polythiol are allowed to react in a similar manner, then a cross-linked polythioether structure can develop:

SH ' free radical = - polyene - = + HS - * -

I SH SH initiator

S- . s- f $

polythioether - S - - S - polyene - S - - S- I I S ------polyene S

These polyene-polythiol systems can be rapidly cured by any source of free radicals such as UV (photoinitiator or photosensitizer), EB, or peroxide (thermal 1 techniques. (30)

PLASMA PROCESSING CHEMISTRY

Microwave or radio frequencies above 1 MHz are applied to a gas under low pressure to produce high energy electrons, ions, and neutral species (plasma) which can interact with organic substrates in the vapor and solid state to produce a wide variety of reactive intermediate species. in a plasma atmosphere are very complex, as outlined in the following sequence: (45-1

The reaction processes that take place

3-1 1

PLASMA REACTIONS

D i s s o c i a t i on

E l e c t r o n Attachment

Dissoc i a t i ve Attachment

A2 t e - - 4 2 A t e-

A2 + e--A - A, + e--A + A-

2

I on i z a t i on

P hotoemi s s i on

A b s t r a c t i on

L t - A + e - -+A2 +2e

A2+A2 + hv

A + B2-AB + B

2,

* Where A2 i s e x c i t e d molecule A2.

These complex r e a c t i o n s can be used t o c o n v e r t s imp le o r g a n i c molecules i n t o v e r y

t h i n (0.1 t o 8 m ic rons ) h i g h l y c r o s s - l i n k e d f i l m s t r u c t u r e s , t o c r e a t e a c t i v e f r e e

r a d i c a l s i t e s on to polymer su r faces so t h a t unsa tu ra ted monomers may be g r a f t e d

on to t h e a c t i v a t e d s u b s t r a t e , and t o c h e m i c a l l y o x i d i z e o r change t h e s u r f a c e

energy c h a r a c t e r i s t i c s of t h e polymer s u b s t r a t e f o r improved adhesion bonding,

c o a t i n g , o r i n k r e c e p t i v i t y c a p a b i l i t i e s . (3)

Organic molecule

very t h i n c ross - l i nked va!Ors ___) f i l m s t ruc tu res

Polymer g r a f t li

Active s i t e s P1 asma

unsaturated 0 v i n y l

Polar f unc t i ona l groups Oxygen

Polymer - Oxygen

Polymer - 3-1 2

Sect ion 4

AP PL I CAT IONS /MARKETS

R a d i a t i o n process ing o f po lymer ic m a t e r i a l s has found widespread commercial use i n

t h e f o l l o w i n g areas:

0 Coat ings 0 P r i n t i n g 0 Adhesives 0 Elec t ron ics /communica t i ons 0 P l a s t i c s and rubber m a t e r i a l s 0 Plasma process ing

The advantages o f r a d i a t i o n process ing polymer t e c h n o l o g i e s over those o f conven-

t i o n a l f o s s i 1 energy-heated process ing techniques i n these areas i n c l u d e :

0 Rapid d r y i n g speeds (seconds o r l e s s ) .

0 Reduct ion o r e l i m i n a t i o n o f o rgan ic s o l v e n t s , thus e l i m i n a t i n g a i r p o l l u t i o n and i n c i n e r a t i o n problems.

d r y i n g ovens and i n c i n e r a t o r s . 0 S i g n i f i c a n t r e d u c t i o n o r e l i m i n a t i o n o f f o s s i l energy-heated

0 Coat ing o f h e a t - s e n s i t i v e m a t e r i a l s ( p l a s t i c s I .

0 Inc reased p r o d u c t i o n r a t e s .

0 More e f f i c i e n t use o f po lymer ic c o a t i n g m a t e r i a l s because o f less p e n e t r a t i o n o f f l o w i n g m a t e r i a l i n t o s u b s t r a t e s .

0

0

0

Savings i n space o f a p p l i c a t i o n equipment.

Manufacture o f p roduc ts w i t h h i g h value-added p r o p e r t i e s .

Development o f p roduc ts t h a t cannot be manufactured by any o t h e r p rocess ing technique.

Each o f these advantages w i l l become apparent i n t h e f o l l o w i n g d i s c u s s i o n s on i n -

d i v i d u a l a p p l i c a t i o n o r market areas assoc ia ted w i t h c u r r e n t and f u t u r e r a d i a t i o n

process ing techno1 o g i es .

4-1

COATINGS

The coatings industry comprises the manufacture, sale, and use of clear and pigmented finishes which protect, decorate, and provide functional properties to a wide variety of surfaces and objects. The product line for this industry can be divided into three general categories: trade sales, industrial finishes, and special -purpose coatings. Trade sales coatings are formulated for normal environmental conditions and find general applications on new and existing residential or commercial building structures. Industrial finishes are usually formulated for original equipment manufacture (OEM) and can be applied to products as part of the manufacturing process. Special purpose coatings are designed for field applications, such as refinishing, or for extreme environmental stress conditions, such as high temperature and corrosion. scription for this industry is shown in Table 4-1.

A generalized product line and product use de-

Radiation processing of coating materials is almost exclusively associated with the industrial finishing market area; major emphasis is on wood finishing, metal coatings ,or decoration, and paper or plastic film coatings, with limited use in wire and automotive applications. ( 4 7 ) - Radiation curable coatings offer several advantages over conventional thermally converted solvent-based coatings systems. In conventional thermal coatings technology a polymer and reactive cross-linking 01 igomer is dissolved in a nonreactive diluent solvent. The ratio of solven polymer-cross-linking oligomer is usually 50 to 60% of the total coating This low viscosity liquid composition is then applied to a substrate and gas-fired oven which removes the ,solvent and sets the polymer cross-link mer into a solid three-dimensional cross-linked network or finished coat process is energy intensive, since most of the thermal input energy goes

to system . baked in a ng oligo- ng. This to heat

the substrate and remove the nonreactive di 1 uent sol vent. Additional thermal energy is also required to activate the cross-linking reaction of the polymer with the cross-linking oligomer in order to effect cure. In many cases the substrate is heat or moisture sensitive and a thermally cured coating operation causes shrinkage-warpage or dehumidification of the substrate which requires an additional manufacturing step to produce a usable finished product. solvent used in conventional coatings technology usually is vented into the atmosphere (which causes pollution), burned, or recycled to make up part o f the thermal energy of the oven used to cure the coating system (Figure 4-1).

The nonreactive diluent

In radiation curable coatings a reactive polymer and coreactive cross-linking oligomer are dissolved in a completely coreactive diluent solvent. This mixture is applied in a similar manner as a conventional thermally cured coating but is cured

4- 2

Table 4-1

COATINGS INDUSTRY - PAINTS AND ALLIED PRODUCTS (SIC 28500-005) (47)

Product Type

Trade sales (architectural coatings) (TS) (SIC 28510-005)

'Industrial finishes (product coatings , OEM; chemical coatings, factory appl led) (IF) (SIC 28520-005)

Special-purpose coatings (SPC) (SIC 28529-005)

Use

"D0-i t-yoursel f", over-the-counter

Exterior solventborne Exterior waterborne Interior solventborne Interior waterborne Architectural lacquers

-

sales

Automotive finishes (primers, sealers, topcoats)

Truck and bus finishes Other transportation finishes

e.g., aircraft, railroad, etc. Marine coatings , including

off-shore structures Appliance finishes Wood furniture and fixture finishes Wood and composition board flat

stock finishes Sheet, strip, and coil coatings on metals

Metal decorating, e.g., can, container, and closure coatings

Machinery and equipment finishes Metal furniture and fixture

coatings Paper and paperboard coatings Coatings for plastic shapes and

films, e.g., packaging Insulating varnishes Magnet wire coatings Magnetic tape coatings

Industrial maintenance paints --interior, exterior

Metallic paints, e.g., aluminum, zinc, bronze, etc.

Traffic paints Automobile and truck refinish

coati ngs Machinery refinish coatings Marine refinish coatings Aerosol paints and clears Roof coatings Fire-retardant paints Multicolor paints

.

4-3

50% Solvent Diluent

50% Polymer and Cross linking Oligomer

I

t I Substrate I

Burned or Vented Into d-, Atmosphere (Pollution) Reclaimed

Thermal

Energy

Recycled or Burned I 1

Cured film Substrate

4

Total Solvent Removal

Polymer and

I

Thermal

.! Substrate

l

Heat Removed from Subst rate

I Substrate

Reactive Solvent Reactive Polymer Reactive Crosslin king

Oligomer

i Substrate

J

Electrical or Cured Film

Light Energy Substrate t

6 L

Finished Product

Conventional Thermally Cured Coating System

Radiation Curable Coating Systems

F i g u r e 4-1 . Technologies (28)

Comparison between Convent ional and R a d i a t i o n Curable Coat ing

4-4

v i a e l e c t r i c a l or l i g h t energy processes and does n o t r e q u i r e d i r e c t thermal ex-

p e n d i t u r e o f energy. S ince t h e r a d i a t i o n c u r a b l e c o a t i n g s a re 100% r e a c t i v e t h e r e

a r e no v o l a t i l e s o l v e n t losses, and t h e l i q u i d c o a t i n g s u p p l i e d t o t h e s u b s t r a t e i s t o t a l l y conver ted i n t o a s o l i d c r o s s - l i n k e d f i l m .

v o l a t i l e emissions assoc ia ted w i t h t h e convers ion process, r a d i a t i o n c u r a b l e c o a t -

i n g s a r e p o l l u t i o n f r e e and are n o t energy i n t e n s i v e processes. Another advantage

o f r a d i a t i o n c u r a b l e c o a t i n g s i s t h a t i n t h e c u r i n g process e l e c t r i c a l o r l i g h t

energy i s absorbed o n l y b y t h e c o a t i n g and i s n o t wasted i n h e a t i n g t h e subs t ra te , -

as i n t h e case w i t h conven t iona l t h e r m a l l y cured c o a t i n g systems. T h i s e f f i c i e n t

use of energy a l l o w s r a d i a t i o n c u r a b l e coa t ings t o be a p p l i e d and processed on hea t s e n s i t i v e s u b s t r a t e s , r e s u l t i n g i n f i n i s h e d p roduc ts r e q u i r i n g r e l a t i v e l y s imp le

manu fac tu r ing o p e r a t i o n s ( F i g u r e 4-1). (28) -

Since t h e r e a r e e s s e n t i a l l y no

Severa l major a p p l i c a t i o n areas f o r r a d i a t i o n c u r a b l e c o a t i n g s a r e d iscussed i n t h e

f o l l o w i n g s e c t i o n s .

Wood F i n i s h i n g s

The wood f i n i s h i n g i n d u s t r y can be r o u g h l y d i v i d e d i n t o wood f u r n i t u r e and f i x t u r e

f i n i s h e s ( th ree -d imens iona l c o a t i n g processes) and wood o r compos i t i on board ( p a r -

t i c l e board) f l a t s tock f i n i s h e s f o r use i n t h e manufacture o f d e c o r a t i v e panels o r f u r n i t u r e .

The t r a d i t i o n a l method o f f i n i s h i n g these p roduc ts i s through f o r c e d h o t a i r o r

i n f r a r e d d r y i n g oven thermal t rea tmen ts o f v o l a t i l e s o l v e n t or water-based c o a t i n g

m a t e r i a l s . ( U V and EB 100% r e a c t i v e c o a t i n g systems) i s i n f l a t s t o c k m a t e r i a l s ; a f u t u r e

t r e n d i s m o d i f i c a t i o n o f these systems f o r three-d imensional c o a t i n g a p p l i c a t i o n s . (48-52)

A t t h e p resen t t ime t h e major i n t e r e s t o f non-IR r a d i a t i o n p rocess ing

Two systems have been developed f o r f i n i s h i n g o f f l a t s tock f o r f u r n i t u r e o r

pane l i ng . The requ i remen ts f o r these c o a t i n g / i n k / a d h e s i v e systems a r e as f o l l o w s :

Wet System Dry System

F i l l e r c o a t i n g F i l l e r c o a t i n g Base c o a t Lamina t i on adhesive G r a i n p r i n t i n k o r Decora t i ve paper, p o l y -

Top c o a t v i n y l c h l o r i d e ( P V C ) f i l m 1 ami n a t i on w i t h wood veneer s t y r e n e (PST) o r p o l y -

Top c o a t

4-5

Wet f i n i s h i n g i n v o l v e s d i r e c t a p p l i c a t i o n and c u r i n g o f l i q u i d s e a l e r s , varn ishes,

and p a i n t s ; d r y f i n i s h i n g i n v o l v e s a p p l i c a t i o n o f a p r e f i n i s h e d d e c o r a t i v e paper o r

p l a s t i c f i l m t o t h e board su r face . (52 ) - A p i c t o r i a l d iagram f o r each system and

t h e i n d i v i d u a l c o a t i n g f u n c t i o n s i s shown i n F i g u r e 4-2. A t y p i c a l r a d i a t i o n p ro -

cess ing wood f i n i s h i n g l i n e i s desc r ibed i n F i g u r e s 4-3 and 4-4. (50) - A summary

o f t h e c o a t i n g c h e m i s t r y assoc ia ted w i t h thermal o r I R , UV/EB polymer m a t e r i a l s f o r

t h e wood f i n i s h i n g i n d u s t r y i s desc r ibed i n Table 4-2.

The advantage o f u s i n g UV/EB r a d i a t i o n process ing t e c h n o l o g i e s ove r I R o r conven-

t i o n a l thermal c u r e systems i s t h a t t h e r e s u l t a n t p roduc t can be more r e a d i l y manu-

f a c t u r e d ; i n some cases a s u p e r i o r p roduc t can o n l y be achieved th rough t h e use o f

low- temperature h igh-energy c u r i n g methods. I n conven t iona l t he rma l c u r i n g c o a t i n g

systems t h e board i s a l s o heated and subsequent ly d r i e d ou t , which r e q u i r e s c o o l i n g

and sometimes r e h u m i d i f i c a t i o n b e f o r e s h i p p i n g t o a f u r n i t u r e manu fac tu re r .

UV/EB c u r i n g t h e board i s f i n i s h e d e s s e n t i a l l y a t ambient temperature w i t h o u t a

major loss o f m o i s t u r e con ten t . Hence, t h e s u b s t r a t e can be processed and shipped

immed ia te l y t o t h e f u r n i t u r e manufacturer . Another advantage t o low thermal energy

c o a t i n g c u r i n g processes i s t h e i r a b i l i t y t o f i n i s h heat s e n s i t i v e s u b s t r a t e s such

as p l a s t i c s , paper, o r p o l y v i n y l c h l o r i d e ( P V C ) v i n y l f i l m s . A t t h e p resen t t i m e

t h e r e a r e approx ima te l y 100 U.S. wood f i n i s h i n g o r manu fac tu r ing companies u s i n g UV

l i g h t c u r a b l e c o a t i n g s and o n l y two o r t h r e e U.S. companies u s i n g EB p rocess ing

equipment f o r manufacture o f h i g h performance low p ressu re l a m i n a t e f i n i s h e d wood p roduc ts . The reasons f o r t h i s d i v i s i o n i n r a d i a t i o n p rocess ing u t i l i z a t i o n a re

p roduc t performance c o n s t r a i n t s and economics. I n f r a r e d c u r i n g o r o t h e r forms o f thermal c u r i n g o f c o a t i n g s a r e s t i l l w i d e l y p r a c t i c e d by t h e wood i n d u s t r y . How-

ever , UV p rocess ing can o f f e r seve ra l major advantages which w i l l be d iscussed i n

t h e c o s t comparisons s e c t i o n o f t h i s r e p o r t . I n cases where o n l y a v e r y s p e c i a l

p r o d u c t i s produced, such as h e a v i l y pigmented panels o r l ow p ressu re l am ina tes , t h e i n i t i a l h i g h c o s t o f EB processor equipment can be j u s t i f i e d . A t y p i c a l EB

wood f i n i s h i n g l i n e i s shown i n F i g u r e 4-5 and EB versus thermal c u r e f i n i s h e d

p r o d u c t performance comparisons a re shown i n Table 4-3. (50,521

With

Meta l Decora t i ve Coat ings

The meta l d e c o r a t i n g i n d u s t r y uses a wide v a r i e t y o f polymer systems t o coa t meta l

cans, crowns, c l o s u r e s , c o l l a p s i b l e tubes, and p r e f i n i s h e d meta l i n t h e fo rm o f

c o i l s . It a l s o i n c l u d e s d e c o r a t i v e f i n i s h e s a p p l i e d b y p r i n t i n g techn iques ( l i t h -

ography and s i 1 k-screen on v a r i o u s meta l s u b s t r a t e s . The t r a d i t i o n a l method o f

f i n i s h i n g these p roduc ts i s u s u a l l y through g a s - f i r e d oven thermal t rea tmen t o f

v o l a t i l e s o l v e n t o r water-based c o a t i n g m a t e r i a l s . The two dominant markets i n

4-6

WET SYSTEM

UV or Electron Cured 50 gm/m2

Topcoat Grain Print Inks Base Coat 30 gm/m2

Very Thin Films (0.1 mil)

Filler Coating 90 gm/m2

Particle Board 0.3-3 cm Thick

DRY SYSTEM

UV or

Topcoat Electron Cured 60 gm/m2

Decorated Paper 30 gm/m2 or Film

Laminating

or Filler Coating Adhesive and 90 gm/m*

Particle Board 0.3-3 cm Thick

~~ ~ -

F i g u r e 4-2. R a d i a t i o n Curable Wood F i n i s h i n g Technology (52) -

4-7

WET FINISHING

Particle Board

P

co I

Clear

Coat I Pigmented Pigmented Grain

Filler Base Coat Print TOP

I

Panel of Decorative

Wood

Printing

Lamination With

Wood Veneer DRY FINISHING

Printing 8 Impregnation

Clear TOP Coat

Tinting I Color

r Varnishing I

Rolling Up I

Gluing on Filled Board

Panel of Decorative

Wood

Figure 4-3. Wood Finishing Operations (50)

P I u3

2 3 3 3

Varnishing of both faces: Speed - 15 to 30 m h i n

Total length of the line - 60 to 65 m.

1 - Tinting of the wood (solvent

2 - Thermal oven 3 - Sanding and vacuum cleaning AI, A2 - Application with roller-

UV - 2 to 4 UV lamps of min 80 W/cm (both faces)

A3 - Application with roller-coater of 15 g/m* on one face only

base)

coater of 15 g/mz

Figure 4-4. Varnishing and UV Curing/Finishing Line f o r F la t Stock Wood Products (50)

Table 4-2

RADIATION CURABLE COATINGS FOR WOOD FINISHING APPLICATIONS (30,36,50)

Coati nq Formul at i on

A1 kyds, polyesters, urea- formal dehyde, vi nyl s , acryl i cs , urethanes ; 30- 65% solids (solvent or water based); clear polymer systems or containing pigments

Acryl ated polyester resin, hexanediol di acryl ate, vinyl pyrrol i done , photoinitiator

Same as above but add silica or titanium dioxide pigments

65 wt percent unsaturated polyester, 35 wt

' percent vinyl monomer: 2-ethyl hexyl acrylate or styrene acryl ic copolymers containing pendant vinyl unsaturation (unsaturation levels, 0.5-1.75 mol of double bonds per 1000 mol wt) and 35-45 wt percent of a vinyl monomer: 2- ethyl hexyl acrylate or styrene

Acryl i c monomers : acryl i c unsaturated epoxy and acrylic unsaturated poly- urethanes monomers: poly- functional vinyl intermediates

Curinq Conditions

Infrared oven 90 to 120 sec cure times

UV processor single lamp, cure time of 10 seconds

UV processor sing1 e lamp, cure time of 10-30 seconds

Cured with 300 keV electrons at 200 kGy/mi n (20 Mrad/mi n) cured with a total dosage of 150 kGy (15 Mrad) electron beam;

Electron-curtain curing

A w l i cat i on

Fi 1 1 er, base-coat and top-coat varnishes

C1 ear varni sh

Filler or base- coat

Coatings fo r vinyl covered flat board stock

4-1 0

Table 4-3

COMPARISON OF PERFORMANCE LIMITS AND TEST VALUES BETWEEN HIGH AND LOW PRESSURE MELAMINE THERMALLY CURED LAMINATES

AND UNIFACE ELECTRON BEAM CURED PANELS (52)

High Low Uniface

Test U n i t Laminate Laminate Values Pressure Pressure Test

Hoffman Scratch Resistance Grams 400 400 1200

Wear Resistance Cycles t o 400 100 145 LD3-3.01 Fai l u r e

Impact Resistance Inches 50 15 24 LD3-3.03

B o i l i n g Water Resistance 20 minutes No E f f e c t S l i g h t E f f e c t No E f f e c t LD3-3.05

High Temperature 20 minutes S l i g h t E f f e c t S l i g h t E f f e c t No E f f e c t Resistance LD3-3.06

4-1 2

t h i s i n d u s t r y a re can c o n t a i n e r s and p r e f i n i s h e d c o i l s t o c k . However, o n l y t h e can

manufacture and d e c o r a t i n g i n d u s t r y has s e r i o u s l y cons ide red t h e use o f UV l i g h t

r a d i a t i o n p rocess ing techno log ies f o r c u r i n g 100% r e a c t i v e i n k s , p igments, o r c l e a r

c o a t i n g systems. A t y p i c a l can c o a t i n g l i n e , t h ree -p iece , and two p i e c e c o n f i g u r e d

w i t h UV p rocess ing equipment i s shown i n F i g u r e 4-6. The U.S. c o i l c o a t i n g indus-

t r y has adopted o t h e r s o l v e n t recove ry or i n c i n e r a t i o n thermal oven equipment modi-

f i c a t i o n s so t h a t i t can c o n t i n u e t o use so lvent-based ( l o w s o l i d s ) c o a t i n g systems

hav ing l ong - te rm proven performance c a p a b i l i t i e s . T h i s i s n o t t h e case, however,

i n Japan where a t l e a s t one major s t e e l company i s u s i n g EB c u r a b l e c o a t i n g s on

me ta l c o i l s tock because o f t h e i r s u p e r i o r f i n i s h and unique p r o p e r t i e s . A more

d e t a i l e d d i s c u s s i o n o f t h i s process w i l l be r e p o r t e d i n t h e s e c t i o n o f t h i s r e p o r t

e n t i t l e d Global Trends i n R a d i a t i o n Process ing o f Polymer ic M a t e r i a l s . (53-57)

I n o t h e r areas, UV c u r a b l e c o a t i n g s a re a p p l i e d t o aluminum o r g a l v a n i z e d s t e e l

t u b i n g f o r bo th d e c o r a t i v e and p r o t e c t i v e purposes. Galvanized s t e e l t u b i n g i s

manufactured f r o m a cont inuous s t r i p o f ga l van ized o r ungalvanized s t e e l which i s g r a d u a l l y formed i n t o t h e d e s i r e d shape o r s i z e , and f i n i s h e d w i t h a UV-curable

c o a t i n g system ( F i g u r e 4-7). A t y p i c a l UV lamp r a d i a t i o n p rocess ing c o n f i g u r a t i o n

f o r c u r i n g c o a t i n g s on a cont inuous t u b i n g o r p i p e l i n e i s shown i n F i g u r e 4-8. The performance c h a r a c t e r i s t i c s f o r seve ra l ga l van ized s t e e l c o a t i n g f o r m u l a t i o n s

are shown i n Table 4-4. (57 ) -

P ac kag i ng C o a t i ngs

P r o t e c t i v e h i g h g l o s s o v e r p r i n t c o a t i n g s have found g r e a t u t i l i t y i n t h e c o n v e r t i n g

and packaging i n d u s t r i e s .

t e c h n o l o g i e s t h i s i n d u s t r y had t h e f o l l o w i n g f i n i s h i n g choices: (58) Befo re t h e development o f r a d i a t i o n c u r a b l e c o a t i n g

0 solvent-base p ress va rn i shes . 0 water-base coa t ings . 0 l i q u i d l a m i n a t i o n s . 0 f i l m l a m i n a t i o n s .

I n shee t - fed l i t h o g r a p h i c p r i n t i n g opera t i ons , so lvent-base press v a r n i s h coa t ings

l e a d on a volume b a s i s . Th i s c l e a r v a r n i s h can be wet o r dry-processed on a press and impar t s a g l o s s y s u r f a c e b u t o n l y f a i r r u b o r ab ras ion r e s i s t a n c e . Water-base

c o a t i n g s a re g e n e r a l l y wet-processed on a s i x - c o l o r press and r e p l a c e t h e so l ven t - -

base press v a r n i s h system; t h e y p r o v i d e f a i r g l o s s and adequate t o f a i r ab ras ion r e s i s t a n c e . L i q u i d l a m i n a t i o n c o a t i n g s a re ca ta l yzed , a p p l i e d o f f - p r e s s on a r o l l -

c o a t e r , and d r i e d o r cu red i n a 3 0 - f o o t oven. Postcards and paperback book covers

undergo t h i s process; t h e c o a t i n g s p r o v i d e e x c e l l e n t g loss and h i g h f i n i s h q u a l i t y ,

4-1 3

Sheets of Tinplate, Aluminum or Tin-Free Steel

Overprint Varnish

Three Piece Can Forming Operations

(Body Formation and End Capping)

Preformed 2 Piece Aluminum Can

Printing Overprint Roller Varnish Roller

Figure 4-6. Radiation Curable Can Line Operation (53,55)

Decorated Product

4-1 4

Surface Treatment and/or UV Curable Coating Application and Processing

Untreated Steel

Surface Treatment and/or UV Curable Coating Application and Processing

Galvanized Steel Fiat Coil Strips

W / Cleaning

Figure 4-7. Galvanized Steel Tubing Line (57)

4-1 5

One of Four UV Lamps One of Three UV Lamps

Galvanized

Aluminum (Small Diameter) Galvanized Steel or Aluminum Tube

Tube (Large Diameter)

Figure 4-8. Lamps (57)

Cross Section o f Tube Line Surrounded by Three o r Four UV

4-16

Table 4-4

PROPERTIES OF TYPICAL UV CURABLE COATINGS FOR GALVANIZED STEEL TUBING (57)

Formu1 a t i on X Y Z

V i scos i t y (cps @25O C) Shrinkage Penci 1 Hardness Crosshatch and tape adhesion (% removal) MEK double rubs 90° bend and tape (% removal a t bend)

Tensi le , p s i E l ongat i on, %

. Modulus, p s i

490 410 260 8.2 7.3 7.9

3H 3H 3H

0 10 15 100 40 100

10% 2 5% 85%

4,800 4,500 3,900 14 9 3

160,000 130,000 140,000

Fog Corros ion Data (Degree o f B1 i s t e r i n g )

100% Re la t i ve Humid i ty (ASTM 2247) a t 38 C. Formul a t i on X Y Z

250 Hours 500 Hours

#10 85% #8 80% #a #10 95% #8 90% #8

5% S a l t Spray (ASTM B-117) a t 35 C; pH 6.5 t o 7.2. Formul a t i on X Y Z

200 Hours 500 Hours

5% #8 90% #4 90% #4 20% #8 Red r u s t Red r u s t

B l i s t e r s ize : #lO=No b l i s t e r s ; #8,6,4 represent b l i s t e r s i n inc reas ing s ize , #4 being t h e l a r g e s t (see ASTM D-714) .

Note: X, Y, and Z represent d i f f e r e n t coa t ing fo rmula t ion design parameters.

4-1 7

b u t t h e y are s o l v e n t based and r e q u i r e l a r g e amounts o f thermal energy and separa te p rocess ing equipment. D i r e c t l a m i n a t i o n o f a p r o t e c t i v e p l a s t i c f i l m , such as a

p o l y e s t e r , i s another method o f a c q u i r i n g h i g h g l o s s and a p r o t e c t i v e cove r ing , b u t

t h i s process i s expensive and r e l a t i v e l y s low compared t o t h e c o n v e n t i o n a l systems.

og raph ic and f l e x o g r a p h i c presses

beam equipment i s a l s o used on a

o p e r a t i o n s . (59,601

F l o o r Coat ings

a re

i m i

R a d i a t i o n process ing, p redominan t l y UV, p rov ides a l i q u i d c o a t i n g system o r l i q u i d

l a m i n a t i n g system compa t ib le w i t h t h e p r i n t e r ’ s e x i s t i n g equipment and c u r r e n t

p r o d u c t i o n schedule. A r a d i a t i o n c u r a b l e c o a t i n g process a l l o w s f o r b e t t e r q u a l i t y

t han t h e press v a r n i s h o r water-base coa t ings , and e q u i v a l e n t p r o p e r t i e s t o a f i l m l a m i n a t i o n process. U l t r a v i o l e t c u r i n g i s now w e l l e s t a b l i s h e d ; hundreds o f l i t h -

equipped w i t h UV lamp systems. E l e c t r o n

ed b a s i s i n v e r y h i g h volume p r i n t i n g

R a d i a t i o n c u r a b l e c o a t i n g s have made a major impact on manufacture o f permanent

h i g h g l o s s , no-wax v i n y l f l o o r i n g t i l e s and sheet p roduc ts . The c o n v e n t i o n a l

method o f s u r f a c e f i n i s h i n g these p roduc ts i n v o l v e s a p p l i c a t i o n o f a s o l v e n t (hy-

drocarbon o r water based) o r 100% s o l i d s two component urethane c o a t i n g t o t h e

s u b s t r a t e (3-5 m i l t h i c k u n i f o r m c o a t i n g s ) f o l l o w e d b y low temperature thermal

c u r i n g techn iques o r b y m o i s t u r e c u r i n g i socyana te r e a c t i o n s under room temperature

s t o r a g e and d r y i n g c o n d i t i o n s . (61 ) -

R a d i a t i o n c u r a b l e c o a t i n g s (UV i s t h e energy system o f c h o i c e f o r t h i s i n d u s t r y )

c o n t a i n 100% s o l i d s and have b e t t e r o v e r a l l p h y s i c a l and chemical p r o p e r t i e s than

t h e i r conven t iona l urethane polymer c o a t i n g c o u n t e r p a r t s (Table 4-5). These UV--

c u r a b l e c o a t i n g s a re tough and can be e a s i l y a p p l i e d t o sheet o r c u t t i l e p roduc t

l i n e s as shown i n F i g u r e 4-9. (62,631

Wire Coat ings

R a d i a t i o n ( U V ) c u r a b l e c o a t i n g s f o r w i r e a re m a t e r i a l s t h a t can be processed i n t o

h i g h l y c r o s s - l i n k e d , tough, f l e x i b l e f i l m s . They can be coated and cured on e i t h e r

ba re o r i n s u l a t e d w i r e a t h i g h l i n e speeds u s i n g simple, low-cost equipment ( F i g u r e

4-10).

a p p l i c a t i o n i s magnet w i r e enamels, which a re coated c o n v e n t i o n a l l y w i t h s o l u t i o n s

c o n t a i n i n g t o x i c o r h i g h b o i l i n g p o i n t s o l v e n t s , r e s u l t i n g i n a i r p o l l u t i o n prob-

lems and consumption o f l a r g e amounts o f gas t o ope ra te t h e d r y i n g l c u r i n g ovens

and a n t i p o l l u t i o n a f t e r b u r n e r s . U l t r a v i o l e t c u r a b l e magnet w i r e enamels e l i m i n a t e

F i l m c o a t i n g s o f 10 m i l s a r e e a s i l y a t t a i n a b l e i n one pass. A t y p i c a l

4-1 8

Table 4-5

COMPARISON OF PROPERTIES FOR CONVENTIONAL AND RADIATION CURABLE COATINGS FOR VINYL FLOORING PRODUCTS (61)

Urethane Coat inq Abrasion Resistance

None 300 micrograms l o s t per cyc le us ing a Tabor Abrader CS-10 wheel w i t h a 500 gram load

Conventional 75- 100 micrograms Urethane Coating l o s t per cyc le

UV curab le u re- 20 micrograms thane a c r y l i c s l o s t per cyc le

S t a i n Resistance, Solvent Resistance L i pst ick /Mustard

No res is tance t o None methyl e t h y l ketone (MEK)

F a i r res is tance t o Mustard on ly MEK

Excel 1 en t MEK res i stance

Excel 1 ent

4-1 9

Calendar Emboss Direct UV Cure Rolls and/or Roll

QQQQ 12OOF

J b Sheet

Print Coater

160-180°F 80-200 ft/min

110-220°F 0.2-15 sec

Sheet or Post-Cut Tile

Forming Emboss Cut and/or Print

Direct Roll

Coater

UV Cure

J O -

on c

Precut Tile

Figure 4-9. Radiation Curable Floor Sheet and Floor T i l e Product Line (63)

4-20

II Ball Die Mercury UV Lamp

UV Curable Wire Coating

I--- 1 I

L I

Pulsed Xenon A * E ----- - Lamp

1 I Snubber I I

Figure 4-10. Typical Wire Coating Lines (64)

4-21

these problems w h i l e m a i n t a i n i n g acceptable performance p r o p e r t i e s (Tab le 4-61, (64 ) -

Other nonmagnet w i r e a p p l i c a t i o n s f o r r a d i a t i o n c u r a b l e polymers a r e as f o l l o w s :

@ Pr imary i n s u l a t i o n where a c r o s s - l i n k e d polymer i s r e q u i r e d f o r thermal , and s o l v e n t r e s i s t a n c e .

As an ove rcoa t f o r g lass and t e x t i l e b r a i d w i r e t o p reven t b r a i d u n r a v e l i n g and t o impar t s o l v e n t and f l ame r e s i s t a n c e .

As a t h i n overcoat on p o l y v i n y l c h l o r i d e i n s u l a t e d w i r e t o impar t :

@

@

- improved s l i p , - improved heat r e s i s t a n c e , - improved appearance

As a t h i n overcoat on p o l y e t h y l e n e i n s u l a t e d w i r e t o i m p a r t :

- improved heat r e s i s t a n c e , - g r e a t e r f l ame re ta rdance

@ Pr imary i n s u l a t i o n i n t h e 5-10 m i l t h i c k range f o r smal l -gage w i r e r e q u i r i n g t h i n w a l l i n s u l a t i o n .

T r a n s p o r t a t i o n (Automot ive 1 Coat ings

R a d i a t i o n c u r a b l e c o a t i n g s ( u s i n g e l e c t r o n beam techn iques ) were f i r s t i n t r o d u c e d

t o t h e automot ive i n d u s t r y i n t h e e a r l y 7 0 ' s b y t h e Fo rd Motor Company t o f i n i s h

c e r t a i n t ypes o f p l a s t i c i ns t rumen t panels. Th is technology was d i s c o n t i n u e d i n

1979 i n f a v o r o f o t h e r compet ing types o f m a n u f a c t u r i n g / f i n i s h i n g o p e r a t i o n s .

Recen t l y , however, r a d i a t i o n c u r a b l e c o a t i n g s ( U V , EB, and I R ) have found an oppor-

t u n i t y i n f i n i s h i n g automot ive hubcaps and wheel r i m s i n t h e U.S., Japan, and

Europe. I n one U.S. o p e r a t i o n ( Jay P l a s t i c s , Mans f ie ld , Ohio) a s p e c i a l i z e d meta l

s p u t t e r - c o a t i n g l i n e runs high-speed I R and UV c u r a b l e base c o a t i n g and t o p c o a t i n g

m a t e r i a l s .

e x p e n d i t u r e f o r t h e company, which based i t s s e l e c t i o n on t h e s h o r t p roduc t c y c l e

t i m e (70% s h o r t e r :

su r faces , and low c o s t p roduc t ach ievab le w i t h t h e new system.

Th is f i n i s h i n g l i n e ( F i g u r e 4-11) rep resen ted a v e r y l a r g e c a p i t a l

45 minutes versus 3 t o 4 hou rs ) , h i g h r e f l e c t i v i t y p roduc t

PRINTING

The p r i n t i n g i n k i n d u s t r y , l i k e t h e c o a t i n g i n d u s t r y , has many s e c t i o n s , each one

s u p p l y i n g a s p e c i a l market area. A rough e s t i m a t i o n o f t h e p r o d u c t l i n e d i v e r s i t y

o f t h i s i n d u s t r y i s shown i n Table 4-7 which r e l a t e s v a r i o u s p r i n t e d p roduc ts w i t h

t h e i r e q u i v a l e n t d o t d e n s i t y ( d o t s pe r i n c h ) requi rements and p r i n t i n g p ress cap-

4-22

Table 4-6

AVERAGE PROPERTIES OR RADIATION CURABLE COATINGS IN MAGNET WIRE APPLICATIONS (64)

Average Property ProPerties Values

Modul us (psi ) Tensile (psi) Percent elongation Dielectric constant 60 Hz Dielectric constant 1 MHz Dissipation factor 60 Hz Dissipation factor 1 MHz Volume resistivity (ohm-cm) Surface res i st i vi ty Dielectric strength (volt/mil) Arc resistance (sec) Cut through (C) Snap test Scrape (9)

6,000-250,000 1,000-7,400 6-340

3.81-8.03 2.49-5.75 0.006-0.1 0.01-0.07

6.6x1Ol2-5. 1x1Ol5 3 ~ 1 0 ~ - 3 . 6 ~ 1 0 ~ ~

865-1,050 3.2-111

290-335 Pass 600-1,200

Note: chemistry, 0.5 t o 10 mil films cured at line speeds up to 150 ppm.

UV-curable coatings based on W. R. Grace thiol-polyene

4- 23

Start

Topcoat Line (60 ft)

Figure 4-11. F i n i s h i n g L ine f o r High-speed I R and UV Curable Coatings (65)

4-24

T a b l e 4-7

P R I N T I N G INDUSTRY PRODUCT D I V E R S I T Y (661

4

W Textile Imaging

Wood Grain Paneling

Address Labels, No OCR E Computer Letters, No OCR 2 2 Computer Letters, OCR

Bus. Forms Imprint E Bus. Forms, Complete 8 Computer Reports

Tags Mass Paperback “Best Seller” Hardbound

3 Technical, Short Run 0 Deluxe Hardbound 8 Art Quality Book

Scroll Book Proof Book

+ Wallpaper

3 Newspapers and Similar 8 Gen. Magazines, etc. 6 Quality, 4 Color 0 n s

5 (3 Low Quality Z Medium Quality

High Quality gz

3 2

8 E 2-Color 4-Color, Quality

Y

n

Computer Line Printer Flexographic Press Offset Press Letterpress Gravure

0 200 400 600 800 1000

4- 25

a b i l i t i e s r e q u i r e d t o produce them. (66 ) - major p r i n t i n g processes: l e t t e r press, l i t h o g r a p h y , f l exog raphy , gravure, and

screen p r i n t . Each process and t h e r e q u i r e d equipment can be desc r ibed as

f o l l o w s . (67,681

T h i s i n d u s t r y can be d i v i d e d i n t o f i v e

L e t t e r p r e s s Process

The l e t t e r p r e s s process ( F i g u r e 4-12) uses r a i s e d c h a r a c t e r s on f l a t o r cu rved

su r faces which a re i nked and then pressed i n c o n t a c t w i t h t h e paper, c o r r u g a t e d

c a r t o n s , o r p l a s t i c f i l m s u b s t r a t e s i n o rde r t o e f f e c t image t r a n s f e r . These

presses can r u n a t 1500 t o 20,000 impress ions per hour, use i n k s hav ing v i s c o s i t i e s between 2 and 400 p o i s e a t 25 C and can d e l i v e r f i l m t h i c k n e s s va lues i n t h e 3-5 p m

r e g i o n . (69-71)

L i t h o g r a p h y

I n a l i t h o g r a p h i c press o p e r a t i o n , bo th t h e p r i n t i n g s u r f a c e and t h e impress ion

a re c a r r i e d on c y l i n d e r s .

polymer, rubber , or p l a s t i c . The n o n p r i n t i n g impress ion c y l i n d e r i s a wa te r -

w e t t a b l e h igh-energy s u r f a c e c o n s i s t i n g o f a g r a i n e d t h i n meta l p l a t e (aluminum,

z i n c , s t a i n l e s s s t e e l ) su r face . Another v a r i a t i o n o f t h i s techn ique i s t o use a

b ime ta l p l a t e compr i s ing a p r i n t i n g area o f copper and a n o n p r i n t i n g area o f chromium. The p r i n t i n g p l a t e i s water dampened and inked s u c c e s s i v e l y b y two s e t s o f

r o l l e r s f o l l o w e d b y d i r e c t c o n t a c t w i t h a paper s u b s t r a t e .

o f f s e t t h i s process such t h a t t h e i n k f rom t h e image i s t r a n s f e r r e d f i r s t t o a

rubber b lanke ted c y l i n d e r and then f rom t h e rubber s u r f a c e t o t h e paper, meta l o r

The p r i n t i n g s u r f a c e i s u s u a l l y a photo-hardened n a t u r a l

I t i s a l s o p o s s i b l e t o

es

a t

p l a s t i c s u b s t r a t e c a r r i e d on an impress ion c y

o f l i t h o g r a p h i c i n k s range f r o m 100 t o 800 PO

f i l m t h i c k n e s s va lues i n t h e 2 t o 3 pm range.

i n d e r ( F i g u r e 4-13). The v i s c o s i t

se a t 25 C and a r e u s u a l l y a p p l i e d (72-74)

F lexography

F lexography i s a method o f p r i n t i n g s i m i l a r t o l e t t e r p r e s s o r " r e l i e f " p r i n t i n g ,

i n t h a t t h e image p o r t i o n s a re r a i s e d above t h e nonimage areas f o r p r i n t i n g ( F i g u r e

4-14). F lexograph ic p r i n t i n g employs rubber o r e l a s t o m e r i c p r i n t i n g p l a t e s and

c y l i n d e r s , and uses v e r y r a p i d d r y i n g f l u i d i n k s hav ing v i s c o s i t i e s i n t h e range o f

0.5 t o 5 p o i s e a t 25 C. The f l e x o g r a p h i c p r i n t i n g process i s un ique among t h e

processes o f p r i n t i n g i n t h a t i t was developed p r i m a r i l y f o r t h e p r i n t i n g o f a vas t

range o f packaging m a t e r i a l s . Th i s p r i n t i n g system has developed as a web f e d

method o f p roduc ing cont inuous r o l l f o rm f e e d i n g f o r wrappings, bag making, e t c .

4-26

c Q h

4- 27

Ink-Distributing

Water Dampening

System

Blanket Cylinder

Figure 4-1 3 . Lithography Process (67)

4-28

Substrate

Rubber Printing Plate /

Ink Fountain 1

Impression Cylinder

F i gure 4-1 4. F1 exography Process (67)

4-29

The rubber p r i n t i n g p l a t e s used i n t h e process o f f e r advantages over o t h e r p r i n t i n g

processes by t h e i r a b i l i t y t o p r i n t on an ex t remely wide range of m a t e r i a l s . Also

advances i n techniques f o r p r i n t i n g m u l t i - c o l o r h a l f t o n e work have opened up new

commercial areas o f t h e p r i n t market.

I n i t s most common form, t h e f l e x o g r a p h i c p r i n t i n g method comprises a f o u r p a r t

system, as f o l l o w s :

0 A rubber covered f o u n t a i n r o l l which t u r n s i n a ba th o f i n k ,

0 A smooth or engraved i n k t r a n s f e r r o l l which runs f r o m f o u n t a i n r o l l t o p r i n t i n g p l a t e ,

0 A p l a t e c y l i n d e r ,

0 An impress ion c y l i n d e r - t o m a i n t a i n p ressure between paper, e t c . and t h e p l a t e c y l i n d e r .

S l i g h t v a r i a t i o n s f rom t h i s common f l e x o g r a p h i c p r i n t i n g system are p o s s i b l e de-

pending on t y p e o f work t o be p r i n t e d and t h e equipment i n use; f o r example, a doc tor b lade may be i n t r o d u c e d i n s t e a d o f an i n k t r a n s f e r r o l l e r . Other v a r i a t i o n s

a l l o w t h e f o u n t a i n r o l l e r t o i n k t h e impress ion p l a t e s d i r e c t l y w i t h o u t u s i n g an

i n k t r a n s f e r r o l l e r . I n i t s bas ic fo rm t h e p r i n t i n g press i s made up o f a combina-

t i o n o f unwinding, p r i n t i n g , d r y i n g , and r e w i n d i n g u n i t s . (75,761

Gravure

I n gravure p r i n t i n g a p r i n t i n g s u r f a c e i s e i t h e r c h e m i c a l l y o r m e c h a n i c a l l y en-

graved w i t h a range o f " c e l l s " which v a r y i n depth, c r o s s - s e c t i o n a l area, and d i s - t r i b u t i o n , depending on t h e p r i n t des ign r e q u i r e d and t h e engrav ing method

used.

The p r i n t i n g c y l i n d e r may c o n s i s t o f a s o l i d i r o n base (mounted on a s h a f t ) on

which a l a y e r o f copper i s depos i ted .

s e q u e n t l y be chromium p l a t e d t o g i v e r e s i s t a n c e t o wear d u r i n g l ong press runs .

A l t e r n a t i v e l y , t h e copper may be i n t h e f o r m o f a c y l i n d r i c a l s leeve which f i t s on to a separate base.

Th is copper l a y e r i s engraved and may sub-

The p r i n t i n g c y l i n d e r i s g e n e r a l l y mounted i n t h e gravure machine so t h a t i t i s p a r t i a l l y covered by t h e i n k which i s p laced i n an i n k duc t , and, when i t s r o t a t e d ,

a f l e x i b l e doc tor b lade removes s u r f a c e i n k , l e a v i n g i n k o n l y i n t h e c e l l s . Thus when a s u b s t r a t e i s p laced i n c o n t a c t w i t h t h e c y l i n d e r under t h e impress ion o f a

4-30

rubber back ing r o l l e r , t h e i n k i n t h e c e l l s t r a n s f e r s t o t h e s u b s t r a t e . The grav- u r e i n k u s u a l l y d r i e s e n t i r e l y by evapora t i on , t h e l i q u i d ( o r s o l v e n t ) p o r t i o n

o f t h e i n k be ing removed d u r i n g t h e d r y i n g process.

and nonabsorbent su r faces t o be p r i n t e d i n b o t h r e e l and sheet fo rm and, p r o v i d e d

t h a t a l l l i q u i d components o f t h e i n k are removed, t h e p r i n t s may be r e r e e l e d i m -

m e d i a t e l y f o l l o w i n g p r i n t i n g . The v i s c o s i t y o f t h e i n k s used i n t h i s process

v a r i e s f r o m 0.3 t o 2 p o i s e a t 25 C and t h e s u b s t r a t e s p r i n t e d may be paper, board, f o i l , o r f i l m m a t e r i a l s w i t h i n k f i l m t h i c k n e s s va lues between 8 t o 12 pm F i g u r e

T h i s enables b o t h absorbent

4-15). (77,78)

Screen P r i n t i n g

Screen p r i n t i n g i s e s s e n t i a l l y a s t e n c i l i n g o p e r a t i o n i n which heavy i n k f i l m s ( i n k

v i s c o s i t y va lues range f rom 1,000 t o 4,000 cps w i t h f i l m t h i c k n e s s va lues r a n g i n g

f r o m 30 t o 70 p m ) a re a p p l i e d by brush o r b lade on to a preimaged p r i n t i n g screen

s u b s t r a t e ( F i g u r e 4-16). The p r i n t i n g screen can be s i l k , ny lon , o r me ta l ; t h e image i s prepared on t h e screen b y p h o t o l i t h o g r a p h y techniques.

be ing used on t e x t i l e s , r i g i d and f l e x i b l e p l a s t i c s u b s t r a t e s (such as p l a s t i c

cups, v i n y l wa l l paper f i l m s ) , and p r i n t e d c i r c u i t boards f o r t h e e l e c t r o n i c s

i n d u s t r y . (68)

Screen p r i n t i n g i s

R a d i a t i o n Cur ing A p p l i c a t i o n s i n P r i n t i n g

P r i n t i n g i n k manufacturers and p a r t i c l e board f i n i s h e r s were t h e f i r s t t o commer-

c i a l i z e UV techno logy as an a l t e r a t i v e t o conven t iona l t h e r m a l l y cu red ( n a t u r a l

gas) so lvent-based i n k and c o a t i n g systems. U l t r a v i o l e t r a d i a t i o n process ing,

r a t h e r than EB, was p r e f e r r e d because o f t h e compact s i z e , low c o s t , f a s t produc-

t i o n r a t e s , p roduc t des ign f l e x i b i l i t y , l a c k o f p o l l u t i o n , and ease o f mainten-

ance. A i r p o l l u t i o n l e g i s l a t i o n i n C a l i f o r n i a and p o s s i b l e f o s s i l f u e l energy c o s t

i nc reases a r e s t i l l i ssues o f t oday t h a t f a v o r s o l v e n t - f r e e , low-energy r a d i a t i o n

c u r a b l e i n k p rocess ing systems. Other advantages o f UV and EB processes are t h e

a b i l i t y t o r e p l a c e thermal oven c u r i n g u n i t s w i t h a s u b s t a n t i a l r e d u c t i o n i n c o s t

and even g r e a t e r r e d u c t i o n i n f l o o r space requi rements.

o p e r a t i o n s t h e s i z e and c u r e speed assoc ia ted w i t h UV o r EB processors a l l o w f o r

i ns tan taneous c u r i n g between s t a t i o n s and e l i m i n a t e s problems o f b l o c k i n g o r smear-

i n g . S ince r a d i a t i o n c u r a b l e i n k s remain l i q u i d (100% r e a c t i v e l i q u i d systems)

u n t i l a c t i v a t e d b y e lec t romagne t i c r a d i a t i o n , t h e y do n o t d r y i n i n k r e s e r v o i r s as

i s t h e case w i t h conven t iona l s o l v e n t a p p l i e d i n k systems. Some genera l charac-

t e r i s t i c s o f UV o r EB c u r a b l e i n k f o r m u l a t i o n s a r e shown i n Table 4-8; a two c o l o r

o f f s e t p r i n t i n g p ress o p e r a t i o n f i t t e d w i t h e i t h e r UV o r EB r a d i a t i o n p rocess ing

I n m u l t i c o l o r p r i n t i n g

4-31

\ Impression Cylinder

Printing Plate

Cylinder

Doctor Blade

\

Ink Reservoir

Fi gure 4-1 5. Gravure Printing Process (67)

4-32

Ink Applicator Blade

Imaged Screen

Figure 4-16. Screen P r i n t i n g Process (67,681

4-33

Table 4-8

STANDARD (CONVENTIONAL THERMAL CURE) AND UV/EB INK FORMULATIONS (68)

Lithoqraphic or Standard Ink

Li tho1 Rubine Pigment 2 0% Drying Oil A1 kyd 1 5% Phenol i c Res i n 3 0% Driers, Other Additives 4% 470 Oil 3 1%

100%

Standard Gravure Ink

Lithol Rubine Pigment 10.0% Ni trocell ul ose 7.0 Maleic Rosin Ester 4 .0 n-Propyl Acetate 60.0 To1 uene 19.0

100.0%

Standard FlexoqraDhic Ink

Lithol Rubine Pigment 11.0% Polyamide Resin 12.0 Add i ti ves 2.0 Ethanol 35.0 N- ProPanol 30.0 N-Probyl Acetate 10.0

100.0%

Standard Screen Ink

Lithol Rubine Pigment 30.0% Thermoplastic Vinyl

Resin 10.0 Thermoplastic Acryl ic

Resin 15.0 Addi ti ves 5.0 Cyclohexanone 20.0 IsoDhorone 10.0 Butyl Cell os01 ve 10.0

100.0%

Evaluation properties: Cure, scr

UV/EB Ink

Pigment 2 9% UV Vehicle 5 4% Photoinitiatora 5% Multi-functional Monomer 10% Add i t i ve s - 2%

100%

UV/EB Ink

Pigment 47.6% 01 i gomer 15.0 Monomer 27.4 Photoinitiatora 5.0 Additives 6.0

100.0%

UV/EB Curable Flexo Ink

Pigment 44.0% 01 i gomer 15.0 Monomer 32.0 Photoinitiatora 5.0 Additives 4 . 0

100.0%

UV/EB Screen Ink

Pigment

01 i gomer

Monomer Photoini t Additives

. . tch resistance, rub re flexibility, adhesion, gloss, pr and odor after curing.

60.0%

15.0

15.0 atora 5.0

5.0

100.0%

i stance, n t strength ,

motoinitiator is not required in the EB ink formulations.

4-34

equipment i s shown i n F i g u r e 4-17. (79,801 The m a j o r i t y o f t h e p r i n t i n g i n d u s t r y

u t i l i z e s UV l i g h t p rocess ing equipment (ove r 300 i n s t a l l a t i o n s ) , b u t EB p rocess ing

o f i n k m a t e r i a l s i s be ing used i n s p e c i a l v e r y h i g h q u a l i t y g r a p h i c a r t s a p p l i c a -

t i o n areas where speed and c e r t a i n p r o d u c t i o n techniques can o n l y be achieved w i t h

EB technology.

The major areas i n t h e p r i n t i n g market pene t ra ted by r a d i a t i o n p rocess ing (a lmos t

e x c l u s i v e l y U V ) have been i n t h e o f f s e t ( l i t h o g r a p h i c ) , s i l k screen, and, t o some

degree, f l e x o g r a p h i c areas; v e r y l i m i t e d i n roads have been made i n t o g ravu re market

segments. P a r t o f t h e reason f o r l a c k o f market p e n e t r a t i o n i n t h e g ravu re area i s

due t o competing techno log ies such as water-based i n k s and s o l v e n t r e c l a i m o r i n -

c i n e r a t i o n equipment m o d i f i c a t i o n s now r e a d i l y a v a i l a b l e f o r i n s t a l l a t i o n on e x i s t -

i n g p r i n t i n g equipment. i n g o p e r a t i o n s a r e i n t h e p u b l i s h i n g / p r i n t i n g t r a d e (books , p e r i o d i c a l s , composer

p r i n t i n g ) and packaging t r a d e (meta l and p l a s t i c c o n t a i n e r b o t t l e l a b e l s , f o l d i n g

paperboard c a r t o n s f o r f o o d and beverages, wraps, de te rgen ts , tobacco, cosmet ics, and medic ines 1.

The two most i m p o r t a n t areas f o r UV p r i n t i n g i n k process-

A un ique method o f p r i n t i n g rounded p l a s t i c c o n t a i n e r s has been demonstrated u t i -

l i z i n g UV energy d i r e c t e d a t t h e p roduc t on a s p i n n i n g mandrel apparatus r a t h e r

t h a n on a l i n e a r p r o d u c t i o n l i n e c o n f i g u r a t i o n ( F i g u r e 4-18). Concepts o f u l t r a -

v i o l e t d r y i n g o f i n k s on p l a s t i c c o n t a i n e r s (cups, t ubs , j a r s , tubes, and b o t t l e s )

has d r a m a t i c a l l y reduced t h e u n i t c o s t o f p roduc ts w i t h an average i n c r e a s e o f 33%

p r o d u c t o u t p u t pe r p r i n t e r due t o e l i m i n a t i o n o f c o n t a i n e r h a n d l i n g problems. (81)

ADHESIVES

The adhesives i n d u s t r y can be c a t e g o r i z e d as d i f f u s e and u n s t r u c t u r e d ; p robab ly

more than 1,000 manufacturers supp ly a ve ry d i v e r s e end-use market area (Table

4-9).

t h i s i n d u s t r y . The p r i n c i p a l adhesives b y t y p e a re s y n t h e t i c r e s i n s , n a t u r a l

r e s i n s , sea lan ts , and cau lks . These broad market area c l a s s i f i c a t i o n s ( F i g u r e

4-19) cover a wide range o f p roduc ts t h a t use approx ima te l y 38 d i f f e r e n t t ypes of

polymer m a t e r i a l s (Tab le 4-10) b r o a d l y c l a s s i f i e d as p ressu re s e n s i t i v e o r nonpres-

s u r e s e n s i t i v e . The same genera l po l ymer -so l ven t c l a s s i f i c a t i o n scheme ( h i g h s o l i d s , powder, 100% s o l i d s , e t c . ) as t h e one f o r t h e c o a t i n g s i n d u s t r y i s used i n

t h e adhesives i n d u s t r y (Tab le 4-11). (82 ) - R a d i a t i o n p rocess ing o f adhesive mate-

r i a l s i n v o l v e s a major use o f s y n t h e t i c polymers and i s commonly assoc ia ted w i t h a

s t r u c t u r a l o r s p e c i a l t y market area. A breakdown o f t h i s s t r u c t u r a l and s p e c i a l t y

adhesive market area f o r 1983 i s shown i n Tab le 4-12. (83)

Approx imate ly e i g h t major producers account f o r about 30% o f t h e o u t p u t f o r

4-35

EB Generator

P I w ln

uv cure

Unit Roll on Processing PaDer

Two Colour Off Set

Triode System

I I

Ink

Figure 4-17. Offset Press Process w i t h UV Cure and EB Cure Processing Units (a)

On-Mandrel Dryer Configuration for Tapered Wall Containers (64 sq ft Total Processor Area Required)

Light Shielding - Take Off Tube

to Counter

Print

" O V Pretreat for Adhesion Promotion

Conventional Cup Dryer Lamp Linear Configuration (184 sq ft Total Processor Area Required)

Figure 4-18. Dryer Configurations (81)

4-37

Packaging

Corrugated board manufacture Carton side-seam and closures Composite bonding of disposable products Bags Labels cups Cigarette and filter manufacture Envelope manufacture Remoi s tenab 1 e products Flexible laminates Speci a1 ty packages Composite containers and tubes

f Tapes 0

03

Packaging tapes Industrial tapes Surgical tapes Masking tapes Consumer tapes

Table 4-9

ADHESIVES MARKET SUPPLIERS AND PRODUCTS (82) -

Construction

Acoustic ceiling panels, floor tile, and continuous flooring installation Ceramic tile installation Counter top lamination Manufacture of prefabricated beams and trusses Carpet 1 ayment adhesives Flooring underlayment adhesives Installation o f prefinished panels Joint cements Curtain wall manufacture Wall covering instal 1 ati on Dry wall lamination adhesives

Other Nonrigid Bonding

Fabric combining Apparel 1 aminates Shoe assembly Sports equipment Book binding Rug backing Flocking cements Air and liquid filter manufacture

Consumer Adhesives

Do-it-yourself products Model and hobby supplies School and stationery products Decorative films

Transport at i on

Auto, truck, and bus interior trim attachment Auto, truck, and bus exterior trim attachment Vinyl roof bonding Auto, truck, and bus assemblies Weatherstrip and gasket bonding Aircraft and aerospace structural assemblies.

Other Rigid Bonding

Shake proof fastening Furniture manufacture Manufacture of millwork, doors, kitchen cabinets, vanitories Appliance assembly and trim attachment Houseware assembly and trim attachment TV, radio, and electronics assembly Machinery manufacture and assembly Supported and unsupported film 1 ami n at i on Manufacture of sandwich panels

I I

A = Construction 15% B = Transportation 3% C = Rigid 5 yo D = Packaging 46%

F = Consumer 5% 7%

E = Non-Rigid 19%

Figure 4-19. Adhesive Market Area C l a s s i f i c a t i o n

4-39

Table 4-10

ADHESIVES INDUSTRY POLYMER-SOLVENT CLASS I F I CATION (82)

Synthetics

Acrylics Modified acrylics Ami nopl asts Anaerobi cs Cyanoacrylates Epoxies Butyl rubber Nitrile (NBR) rubber Neoprene Phenol i cs Polyamides Polyi sobutylenes Polyesters (thermopl asti c) Polyesters (thermosetting) Polyethylene Other po 1 yo 1 ef i ns Block SBR polymers (example: Other SBR resins (styrene butadiene rubber) Other styrene polymers and copolymers Silicones Urethanes (thermoplastic) Urethanes (thermosetting) Acrylic-vinyl acetate copolymers Ethylene-vinyl acetate copolymers (50+% ethylene) Vinyl acetate-ethylene copolymers (50+% vinyl acetate) Other vinyl acetate polymers and copolymers Other vinyls (including polyvinyl alcohol)

Kraton D)

Natural

Bitumens Casein Cellulosics Hydrocarbon resins Terpene resins Rosin and rosin esters Natural rubber Reclal” rubber Starches and dextrines Others

4-40

Table 4-11

ADHESIVE TECHNOLOGIES (82)

Non-Pressure Sensi t i v e s Pressure S e n s i t i v e s

Solvent-borne systems Solvent-borne systems Waterborne systems Waterborne systems N o n - v o l a t i l e s o l i d o r l i q u i d systems Hot m e l t s (100% s o l i d s ) Powders (100% s o l i d s ) Rad i a t i o n c u r a b 1 e systems

(100% s o l i d s ) Two-part systems

Hot m e l t s R a d i a t i o n c u r a b l e systems Reac t i ve systems

Pressure s e n s i t i v e adhesives ( P S A ) a re a p o t e n t i a l s p e c i a l t y market f o r r a d i a t i o n

cu red polymers; p ressu re s e n s i t i v e ( P S ) tapes and l a b e l s c o u l d c o s t l e s s t o manu-

f a c t u r e b y r a d i a t i o n p rocess ing and c o u l d e x h i b i t improved performance p r o p e r t i e s over conven t iona l t h e r m a l l y cured s o l v e n t based adhesive systems. T h i s techno logy

u t i l i z e s a l a r g e volume o f polymers a p p l i e d t o preformed h e a t - s e n s i t i v e tape sub-

s t r a t e s and i s s u i t e d t o bo th EB and UV p rocess ing opera t i ons . (84 L 85)

H e a t - a c t i v a t e d adhesives, h o t m e l t s ( d r y f i l m s t h a t become t a c k y upon a p p l i c a t i o n

o f hea t and p ressu re and upon c o o l i ng fo rm h i gh -pe r f ormance bonds 1 a r e commerci a1 l y

a v a i l a b l e as t a c k - f r e e f i l m s suppor ted on paper, f o i l , f a b r i c , board, o r f i l m sub-

s t r a t e s ( F i g u r e 4-20). (86 ) - R a d i a t i o n p rocess ing a l l ows f o r t h e manufacture o f

t hese p roduc ts w i t h o u t t h e use o f s o l v e n t s f o r improved e f f i c i e n c y , s a f e t y , a i r

p o l l u t i o n c o n s t r a i n t s , and lower o p e r a t i n g c o s t s (Tab le 4-13). Lamina t ing adhes-

i v e s o r adhesives f o r f l e x i b l e packaging i s another area w e l l s u i t e d f o r r a d i a t i o n

p rocess ing opera t i ons . A l a m i n a t o r c o a t e r w i t h a EB ( f l a t p l a n a r cathode) c u r i n g

head i s shown i n F i g u r e 4-21 and a t y p i c a l f i l m l a m i n a t i o n p roduc t performance

sheet i s shown i n Tab le 4-14. Some genera l a p p l i c a t i o n areas f o r h e a t - a c t i v a t e d

adhesive f i l m s and l a m i n a t e s t r u c t u r e s a r e g i v e n i n Table 4-15. (86-88)

ELECTRONICS AND COMMUNICATIONS

R a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s has a t t a i n e d major impor tance i n v a r i -

ous segments o f t h e e l e c t r o n i c s and communication i n d u s t r i e s . c i r c u i t board ( F i g u r e 4-22) i l l u s t r a t e s some o f t h e many d i f f e r e n t c lasses o f p o l y -

m e r i c m a t e r i a l s used i n i t s manufacture. Other m a t e r i a l s used i n t h e e l e c t r o n i c s

i n d u s t r y a re s i l i c o n ( s u b s t r a t e f o r i n t e g r a t e d c i r c u i t s and c h i p s ) , p h o t o r e s i s t s

(used i n p r e p a r i n g c i r c u i t s ) , dopants f o r c i r c u i t a c t i v a t i o n , t h i n f i l m (conformal 1, and e n c a p s u l a t i n g m a t e r i a l s .

A t y p i c a l p r i n t e d

4-41

Table 4-12

STRUCTURAL AND SPECIALTY ADHESIVES MARKETS (E-) ($ million)

Au tomot i ve

Aerospace

Construction

Biomedical /dental

Electronic/pott i ng

Nonrigid

Rigid bonding (anaerobic, cyanoacrylate, etc. )

Total

1983

42

100

460

12

125

200

98

1,037

Table 4-1 3

ADVANTAGES OF HIGH-ENERGY ELECTRON ADHESIVES (86)

Low volatility, 100% convertible

Rapid cure rate

Air pollution eliminated or reduced substantially

Catalysts and initiators are eliminated

No thermal postcure required

Improved process control

Outstanding adhesive film properties: durability, adhesion to organic substrates, reduced shrinkage, and reduced built-in stresses

Ability to use heat-sensitive organic substrates

Potential for cure of composite structures

4-42

Supported Adhesive Film

Self-supported Adhesive Film

H 1 h fi;:;, I Radiation 1 Processing

f n U uv or EB- I

Extrusio -

Finished Product

Finished Product

Figure 4-20. Adhesive F i l m Systems (g6)

4-43

Nip

/

High Energy Electrons

Impression Roll

Primary Film

Secondary \ Unwind Film Unwind Gravure

Roll

Figure 4-21. Laminator Coater System (87)

Rewind

4-44

Table 4-14

TYPICAL PRODUCTS PREPARED WITH A PLANAR CATHODE ELECTRON PROCESSOR (87)

Ad hes i ve

S t ruc tu re ( A )

Voltage

Bond Speed

Web Strength

Nip Temperature

Pan Temperature

Gravure App l i ca to r

Heat Seal Bond

Heat Seal Condi t ions

Temperature

Dwell Time

Psi

Rad ia t ion Curable Acryl ic/Urethane

Low Densi ty Polyethylene (LDPE)/Saran- Coated Po 1 yes ters

Uncoated Polyester/LDPE

Oriented Nylon/LDPE

1.5 t o 2.0 Mrads

155 KV

(A)-800 g (des t ruc t ive) ; (B)-50 g (des t ruc t i ve )

25 fpm

(C)-1000 g (des t ruc t i ve )

Room Temperature

Room Temperature

300 L ine quadrangular

6500 g/ in.

350" F

3 sec.

50

4-45

Table 4-15

ADHESIVE FILM APPLICATION AREAS (86,88)

Applications for Heat Activated Adhesive Films

0 Decals, Labels, Nameplates 0 Garment Repair

0 Bookbinding

0 Construction Panelling

0 Furniture Edge Veneer

0 Multilayer Laminates

0 Carpet Underlay

Upholstery

0 Thermal Insulation

0 Platen Press (credit cards)

0 Protective and Decorative Sheets (printed patterns, metal 1 ized films, particle board, furniture, wall components)

Applications and Structures for Laminate Adhesive Films

0 Food Packaging

0 Flexible Packaging (Non-food)

0 Film/Film

0 Film/Foil

0 Fi lm/Foi 1/Fi lm

0 Paper

4-46

Mylar Silicone molded wrapped integrated circuit Plastic molded

solder maskant EPOXY / pi..;:y I Epoxy staking Teflon compound sleeve for wire

Conform a I acry I ic coating on entire assembly

Figure 4-22. Uses o f P l a s t i c M a t e r i a l s (90)

P r i n t e d Wir ing C i r c u i t Board Showing Diverse

4-47

R a d i a t i o n p rocess ing equipment used t o manufacture e l e c t r o n i c components and sys-

tems covers t h e e n t i r e e lec t romagne t i c spectrum, such as I R , U V - v i s i b l e , e l e c t r o n

beam, plasma and X-ray wavelengths o f energy.

r i a l s i n commercial e l e c t r o n i c dev ices i s growing a t an annual r a t e o f about 10 t o

25%. c u r i n g o p e r a t i o n s can be a t t r i b u t e d i n p a r t t o t h e f o l l o w i n g f a c t o r s :

Use o f r a d i a t i o n p rocess ing o f mate-

The d r i v i n g f o r c e f o r u s i n g r a d i a t i o n p rocess ing over c o n v e n t i o n a l thermal

Super io r p roduc t p r o d u c t i o n and performance c a p a b i l i t i e s . Less f l o o r space r e q u i r e d f o r t h e equipment. F a s t e r l i n e speeds. Greater energy e f f i c i e n c y ( i t r e q u i r e s as much as 80 p e r c e n t l e s s energy t o c o n v e r t f i l m s ) . Fewer problems i n meet ing government p o l l u t i o n requ i remen ts Higher f l a s h p o i n t s . Conversion w i t h o u t d i s t o r t i o n o f h e a t - s e n s i t i v e s u b s t r a t e s . Unique manu fac tu r ing f e a t u r e s .

The f o l l o w i n g paragraphs p r o v i d e a d i s c u s s i o n o f s e l e c t e d e l e c t r o n i c a p p l i c a t i o n s where r a d i a t i o n convers ion i s be ing used. I n some cases i t i s t h e major means o f process ing; i n o t h e r s i t i s o n l y beg inn ing t o be used as a p roduc t p r o d u c t i o n

o p e r a t i on. (89,90 1

I n t e g r a t e d C i r c u i t s ( I C )

I n t e g r a t e d c i r c u i t s c o n t a i n t e n s o f thousands o f c i r c u i t elements and e l e c t r o n i c

components which p r o v i d e memory and l o g i c c a p a b i l i t i e s f o r dev ices r e q u i r e d by t h e

computer and communications i n d u s t r i e s . The manu fac tu r ing process used t o prepare

these I C dev ices i n v o l v e s complex i n t e r r e l a t i o n s h i p s between m a t e r i a l s and f a b r i c a -

t i o n o p e r a t i o n s such as those shown i n F i g u r e 4-23.

thermal (800 t o 1200 C ) o x i d a t i o n processes t o fo rm s i l i c o n d i o x i d e o r chemical

vapor d e p o s i t i o n ( C V D ) t o produce s i l i c o n n i t r i d e su r faces . I m p u r i t y doping i s per formed b y thermal d i f f u s i o n o f boron o r phosphorus, o r b y i o n i m p l a n t a t i o n .

L i t h o g r a p h y and e t c h i n g a re used t o c r e a t e c i r c u i t s on s i l i c o n su r faces .

F i l m f o r m a t i o n i s t h rough

Mounting, l e a d at tachment, and encapsu la t i on a r e t h e f i n a l processes r e q u i r e d t o manufacture t h e i n t e g r a t e d c i r c u i t dev ice. The t h r e e areas o f most i n t e r e s t t o r a d i a t i o n p ro - cess ing a re l i t h o g r a p h y , mounting, and encapsu la t i on . (91,921

L i t h o g r a p h y

L i t h o g r a p h y i s one o f t h e most i m p o r t a n t r a d i a t i o n processes u t i l i z e d b y t h e e l e c -

t r o n i c s i n d u s t r y . L i t h o g r a p h y i s used t o d e f i n e v e r y sma l l geometr ies o r

c o n n e c t i o n / i s o l a t i o n pathways r e q u i r e d i n I C manu fac tu r ing technology. I n t h e

4-48

1 P cc)

cllii, Placement

Into Holder

Photo, E-Beam or X-Ray Lithography

Sing le-Crystal SiO, or Si,N, Silicon Slicer * Film Formation

(Thermal or CVD)

4 Etching Impurity Doping

(Thermal Diffusion 2

or Ion Implantation) I

* Lead F Encapsulate - Integrated ,

Current Attach men t

I

L

Figure 4-23. IC Manufacturing Process (91)

I I

process a s i l i c o n s l i c e i s s p i n coated w i t h a u n i f o r m t h i n f i l m o f r a d i a t i o n sens i -

t i v e po l ymer i c m a t e r i a l c a l l e d a r e s i s t .

o p t i c a l l y , t h e IC p a t t e r n i s f i r s t c rea ted on a mask which i s t hen t r a n s f e r r e d t o

t h e r e s i s t v i a a number o f o p t i c a l techniques ( d i r e c t c o n t a c t p r i n t i n g u s i n g c o l l i -

mated sources o f UV o r v i s i b l e l i g h t ) o r o t h e r l i g h t p r o j e c t i o n techn iques ( F i g u r e

I f t h e l i t h o g r a p h y i s t o be per formed

4-24).

L i g h t s e n s i t i v e r e s i s t s o r p h o t o r e s i s t s a re g e n e r a l l y c l a s s i f i e d i n t o two groups;

n e g a t i v e and p o s i t i v e . Negat ive p h o t o r e s i s t s i n v o l v e t h e c r o s s - l i n k i n g and ge la -

t i o n o f t h e polymer, t he reby p roduc ing an i n s o l u b l e f i l m . The t h r e e main compon-

e n t s i n c o r p o r a t e d i n a n e g a t i v e p h o t o r e s i s t f o r m u l a t i o n a r e a c h e m i c a l l y r e a c t i v e

polymer, a p h o t o s e n s i t i v e agent, and a s o l v e n t . Among t h e r e a c t i o n s i n v o l v e d i n t h e p r o d u c t i o n o f t h i s t y p e o f r e s i s t are: p h o t o c y c l o a d d i t i o n r e a c t i o n s (such as

t h e p h o t o c y c l o d i m e r i z a t i o n o f c innamic ac ids and i t s a l k y d e s t e r s 1, n i t r e n e reac-

t i o n s , and f r e e - r a d i c a l a d d i t i o n r e a c t i o n s (Table 3-4) . (42-1

A p o s i t i v e p h o t o r e s i s t makes use o f an i nc rease i n a c i d i t y upon exposure t o r a d i a -

t i o n , t h e r e b y p roduc ing a f i l m o f g r e a t e r s o l u b i l i t y i n a d i l u t e , aqueous base

s o l u t i o n . The main components o f a p o s i t i v e p h o t o r e s i s t f o r m u l a t i o n a re an a c i d i c

polymer, a p h o t o s e n s i t i v e i n h i b i t o r , and a s o l v e n t . The two main t ypes o f a c i d i c

polymers used i n t h e development o f p o s i t i v e p h o t o r e s i s t s a r e novolacs and

a c r y l i cs .

P o s i t i v e p h o t o r e s i s t s r e q u i r e l o n g e r exposure and more expensive m a t e r i a l s than

n e g a t i v e p h o t o r e s i s t s . P o s i t i v e p h o t o r e s i s t s , however, have good c o n t r a s t and

r e s i s t s w e l l i n g d u r i n g development.

i s t h e same as t h e image on t h e photomask. Negat ive p h o t o r e s i s t images a r e n o t

q u i t e as c l e a r . s w e l l i n g i n t h e exposed r e g i o n s . The s w e l l i n g causes severe d i s t o r t i o n and en-

largement o f t h e image ( F i g u r e 4-25). (42,931

The image which i s produced on t h e s u b s t r a t e

Whi le t h e developer d i s s o l v e s t h e unexposed r e s i s t , i t a l s o causes

Electron-beam d i r e c t p a t t e r n i n g can be performed w i t h o u t a mask b y u s i n g a c o n t r o l -

l a b l e electron-beam processor and an e l e c t r o n - s e n s i t i v e (degradable o r c ross -

l i n k a b l e ) r e s i s t m a t e r i a l ( F i g u r e 4-26). L i t hog raphy has a l s o been achieved w i t h

X-rays b y p r o j e c t i o n th rough a s p e c i a l mask i n c l o s e p r o x i m i t y t o t h e r e s i s t su r - f a c e ( F i g u r e 4-27). The r e s o l u t i o n c a p a b i l i t i e s f o r each o f t h e f o u r l i t h o g r a p h y

system i s g i v e n i n Table 4-16. (94 ) -

4-50

Mirror or Ref lector

Mask -

I \ I

Filter and Condenser Lens System

Reduction Lens System \

Wafer

F i gure 4-24. Lithography Process (92)

4-51

Light

Illuminated Areas a

Silicon Dioxide

Silicon Substrate x Negative Resist: Positive Resist: a Rendered Insoluble n Rendered Soluble

1 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B

Etched Film Patterns: I F i g u r e 4-25. Us ing P o s i t i v e and Negat ive R e s i s t s

Schematic o f C o n t a t t P r i n t i n g (92,93)

4-52

Electron Gun

X-Y Mask Data and

Computer Con t ro I

f 0 I

e-

/ Deflection Coils

Figure 4-26. Electron-Beam Patterning System (92)

4-53

x-ray Target

Electron Beam

Mask Absorber

Resist

Wafer

Figure 4-27. X-Ray Lithography System (92)

4-54

Table 4-16

PHOTOLITHOGRAPHIC PROCESSES (94)

L i thog raphy R e s o l u t i o n

System Present F u t u r e

O p t i c a l 1.5 pm 0.75 p m

uv 0.5 pm 0.25 pm

X-ray 1000 R 100 W

Scanned 1000 W 5 R E Beam (10 8)

A = angstrom o r 10-8 cm

When t h e l i t h o g r a p h y process i s completed, t h e wafer has been s u b j e c t e d t o seve ra l

c y c l e s o f exposure, e t c h i n g , washing, doping, and baking; and i t may c o n t a i n as

many as 500 i n t e g r a t e d c i r c u i t s o r c h i p s . The wafer i s then c u t i n t o i n d i v i d u a l

c h i p s , each o f which i s t e s t e d by a computer ized probe. A 10% y i e l d o f work ing c h i p s i s cons ide red good f o r a new c h i p i n i t s f i r s t p r o d u c t i o n r u n .

Adhes i ves and Encapsu 1 an ts

Once a c h i p has been t e s t e d i t can be a t tached t o a leadframe ceramic package

th rough t h e use o f e l e c t r i c a l l y conduc t i ve adhesives o r nonconduct ive adhesives. F i g u r e 4-28 i s a schematic o u t l i n e f o r c h i p placement on a board s u r f a c e u s i n g

c o n d u c t i v e o r nonconduct ive adhesive systems.

( c o n v e n t i o n a l , thermal and U V ) a re desc r ibed i n Table 4-17 and c e r t a i n s u r f a c e

mount ing d e v i c e requ i remen ts a re g i v e n i n Table 4-18.

P r o p e r t i e s o f two adhesive systems

Encapsulants used i n t h e e l e c t r o n i c s i n d u s t r y a r e p r i m a r i l y epoxy and s i l i c o n - b a s e d

polymer systems, a l t hough urethanes and a c r y l i c s can be used t o some degree i n these a p p l i c a t i o n s . Encapsulants a r e p r i m a r i l y a p p l i e d i n a mo ld ing o p e r a t i o n o r

f i l l i n g o p e r a t i o n and a r e u s u a l l y t h e r m a l l y cu red r a t h e r than r a d i a t i o n processed,

a l t hough pho tocu rab le epoxy r e s i n s m i g h t be cons ide red f o r c e r t a i n p o t t i n g o r en-

c a p s u l a t i o n opera t i ons . (95)

4-55

UV Preirradiation

P I ul cn

a m ,- m /

-B-rCl- &-fi-!25 Adhesive Chip Ultraviolet PC-Board Insertion of Fluxing,

Dispensing Placement Curing Inversion Conventional Soldering, Components and Cleaning

i l I I

Figure 4-28. Automation of Surface-Mounted Boards

1 , I

Table 4-17

Composition

Viscosity

Specific gravity

Gap filling

Cure times Infrared Oven uv

PROPERTIES OF TWO STAKING COMPOUNDS FOR SMD THERMAL VERSUS U V CURABLE MATERIALS (90,91 ,95)

Cured Properties Shore hardness Chip shear strength Max. temperature resistance Solvent resistance

Electric Properties Volume resistivity 8 25OC Breakdown voltage Dielectric constant

Thermal

EPOXY

70,000-600,000 CP

1.19

Up to 0.010 in.

90 sec 8 150OC 10 min 8 1OOOC

--

850 >10 lb

255OC - 15 sec Good

1 x 1016 ohm-cm 2000 V/mil

g3.5

uv Epoxy acrylate

60,000-300,000 CP

1.2

up to 0.010 in.

90 sec 8 15OOC

15 sec 8 2000CW/in. --

850 >10 lb

255OC - 15 sec Good

1 x 10l2 ohm-cm >1500 V/mil

z4

- Note: Surface Mount Device (SMD)

4-57

Table 4-18

ADHESIVES SURFACE MOUNTING D E V I C E (SMD) REQUIRENENTS (90,91 , 9 5 )

SMD Attach Using Conductive Adhesive

Screen p r i n t adhesive

Pick and p lace components

Cure (1-15 minutes)

Test and rework components

SMD Adhesives - Nonconductive

The do t s i ze must stand a t l e a s t 0.006 inch h igh

The do t cannot f low and spread t o the so lder path

When the ch ip i s placed, t he adhesive must have " tack" , i.e., i t must ho ld the ch ips i n p lace through movement i n the produc t ion l i n e

The adhesive must ho ld the ch ip i n p lace dur ing the so lder opera t ion

SMD At tach Using Solder

Apply so lder

P r e - t i n components

Dispense nonconductive adhesive

Pick and p lace components

Cure adhesive

Prebake (80°C f o r 30 minutes)

Solder r e f l o w (210°C t o 250°C f o r 30 t o 60 seconds)

Clean boards, remove f l u x (2-4 minutes)

Test and rework components

Note: Surface Mount Device (SMD)

4-58

P r i n t e d C i r c u i t Boards

P r i n t e d c i r c u i t boards (PCB) can be manufactured u s i n g t h r e e t ypes o f p h o t o r e s i s t

p roduc ts : screen p r i n t i n g i n k s , l i q u i d p h o t o r e s i s t s , and d r y f i l m l a m i n a t i o n

p h o t o r e s i s t s . U l t r a v i o l e t r a d i a t i o n c u r a b l e screen p r i n t i n g i n k s a r e p r o j e c t e d t o

p l a y a more s i g n i f i c a n t r o l e than t h e o t h e r two p h o t o r e s i s t t echn iques i n t h e

f u t u r e f a b r i c a t i o n o f p r i n t e d c i r c u i t boards. The ma jo r t ypes o f p r i n t e d c i r c u i t

boards o f i n t e r e s t t o t h e e l e c t r o n i c s i n d u s t r y a re desc r ibed i n Tab le 4-19. The

t ypes o f screenable p h o t o r e s i s t u l t r a v i o l e t c u r a b l e o r t h e r m o s e t t i n g i n k s used i n

PCB f a b r i c a t i o n a re (1) imaging r e s i s t s , ( 2 ) e l e c t r i c a l l y c o n d u c t i v e i n k s , ( 3 ) s o l d e r masks, ( 4 ) masking i n k s , and ( 5 ) conformal c o a t i n g s . (68,891

Imaging o r p a t i n g r e s i s t s a r e used t o c r e a t e c i r c u i t pathways and p r o t e c t s p e c i f i c

areas on t h e PCB f rom chemical o r e lec t rochemica l e t c h i n g processes. These r e s i s t s

a r e designed t o be removable a f t e r t h e e t c h i n g o r p l a t i n g s t e p has been completed.

E l e c t r i c a l l y conduc t i ve i n k s can be used t o c r e a t e c i r c u i t s d i r e c t l y w i t h o u t hav ing

t o be imaged o r etched.

p r i n t e d d i r e c t l y on to a t r a n s f e r paper b y a screen o r g ravu re process u s i n g an

e l e c t r i c a l l y conduc t i ve t h e r m a l l y cured i n k system. T h i s p a t t e r n e d t r a n s f e r paper

s u b s t r a t e i s t hen overcoated w i t h an adhesive, i n s e r t e d , and t r a n s f e r r e d t o t h e PCB

s u b s t r a t e . Removal o f t h e paper leaves a m e t a l - r i c h s u r f a c e a t t h e t o p o f t h e PCB

which i s immediate ly a c c e s s i b l e f o r s o l d e r i n g o r e l e c t r o p l a t i n g processes. (96 A 97)

I n a new PCB f a b r i c a t i o n process t h e c i r c u i t p a t t e r n i s

So lde r masks a re p r o t e c t i v e c o a t i n g s a p p l i e d t o c i r c u i t boards b y sc reen ing tech -

n iques t o mask e l e c t r i c a l conductor t r a c k s f rom t h e s o l d e r i n g o p e r a t i o n .

cu red f i l m s remain as a permanent p a r t o f t h e c i r c u i t board assembly. Masking

i n k s , u n l i k e t h e o t h e r screen i n k systems, have no e l e c t r i c a l f u n c t i o n on t h e

f i n i s h e d board and a re o n l y used t o mark l o c a t i o n s f o r t h e i n s e r t i o n o f c i r c u i t

components , dates , s e r i a l numbers, e t c . Conformal c o a t i n g s , however , p r o v i d e e l e c -

t r i c a l i n s u l a t i o n f o r t h e e n t i r e PCB and o f f e r b a r r i e r p r o t e c t i o n f r o m t h e e n v i r o n - ment. The t r e n d f o r t h e PCB f a b r i c a t i o n i n d u s t r y i s t o use more UV-curable

m a t e r i a l s . A sumnary o f i m p o r t a n t p r o p e r t i e s o r requ i remen ts f o r some o f t h e major

screen i n k systems a re g i v e n i n Table 4-20. (68,98,99)

These

F i b e r O p t i c s

There has been a major impact on t h e e l e c t r o n i c s and communications i n d u s t r y due t o

f i b e r o p t i c s t e c h n o l o g i e s . F i b e r o p t i c s a re l i g h t w e i g h t , v e r y sma l l , and compact

and p r o v i d e i n t e r f e r e n c e - - f r e e communication between computers and p e r i p h e r a l s .

F i b e r o p t i c s have low a t t e n u a t i o n and can t r a n s m i t a l a r g e amount o f i n f o r m a t i o n

4-59

Table 4-19

MAJOR TYPES OF PRINTED CIRCUIT BOARDS (E)

PCB Description

Print-and-etch Copper circuitry on phenolic single sided 1 ami na te

-~~ ~ -

Plated-through-hole Double-sided or multilayered tin/lead, nickel, or gold plated circuitry

F1 exi bl e Si ng 1 e-s i ded or p 1 ated-throug h- hole with copper or tin/lead circuitry on polyester or polyimide base laminate films

Additive Addition o f copper circuitry directly onto a treated laminate substrate

Application

Low cost, low quality for radio, television telecommunications and appliance industries

applications Military and computer

Automotive and telecommunications

High volume consumer- related products

4-60

Table 4-20

PROPERTIES OF SCREEN I N K SYSTEMS (68)

Solder Masks

Rapid setting radiation curable acrylic or epoxy resins Screenabi 1 i ty Abrasion resistance

Adhesion to copper, tin/lead, nickel and gold Flame resistance Machinabi 1 i ty Low water absorption High gloss or cosmetic appearance where desired Chemical and solvent resistance Resistance to soldering and desoldering

- - . . -. - - __ --Flexibility

Inks and Marking Coatings

Low odor High rub and abrasion resistance Very high gloss where desired Nontoxic (oral) Low coefficient of friction Nonyel 1 ow f i lm High flexibility Low skin irritation Low curing temperatures (radiation curable)

Conformal Coatings

Low moisture absorption and permeabi 1 i ty High resistivity and dielectric strength Abrasion resistance Strippability for easy repair Solderabi 1 i ty Good chemical resistance Short cure time Room temperature cure Easy application Good pot and shelf life Nonpol 1 uti ng Si ngle-component formul ati ng Transparency Low cost

4-61

over longer distances w i t h longer repeater spacing than conventional copper wire telephone cables. (100,101) Optical f i b e r s can be manufactured and coated with a UV curable protect ive f in i sh in an apparatus s imilar t o the one shown in Figure 4-29. The radiat ion ( U V ) curable coatings used t o coat the opt ical fiber must be capable of preserving the optical cha rac t e r i s t i c s and s t rength of the f i b e r , and protect against mechanical damage and moisture penetration. curable coatings fo r opt ical f i be r s i s growing a t a rapid r a t e b u t the actual volume of coating i s very small; 1 mile of optical f i be r weighs only 25

The use of radiat ion

- grams ( 102 , 103 1

Magnetic and Optical Media

Radiation processing technology of fers an improved method of manufacturing magnetic and optical systems fo r the electronics and communications indus t r ies . Even though magnetic and optical media may compete fo r s imilar market areas , the use of some form of electromagnetic radiat ion i n the manufacturing process s t i l l appears t o be a constant fac tor fo r b o t h technologies.

Magnetic Media. Magnetic media products fa1 1 i n t o several general categories such as audio, video, computer and instrument types and f l e x i b l e or r ig id disks . current manufacture of magnetic media by radiat ion processing (almost exclusively E B ) techniques has been driven by three important f ac to r s : (104,105)

The

0 Conventional thermally sens i t ive urethane binder res ins are slow t o cure and r e su l t in products t ha t are sometimes even undercured and could no t perform up t o t h e i r rated spec i f ica t ions . Moisture entrapment in the product and the necessi ty t o s e t aside r o l l s of coated f i lms fo r two weeks i n order t o advance the curing reaction t o a s t a t e of completion were some of the other undesirable f ac to r s of conventional coatings as applied t o t h i s industry. The instantaneous and complete curing of a acryl ate/urethane binder by EB processing techniques i s a much more cont ro l lab le manufacturing method over tha t of the conventional moisture cure polymer binder systems.

Reduced wear of the coating and calendering equipment was noted with EB cure coating as compared w i t h conventional coating systems. This led t o a potent ia l payback in one year fo r a high production r a t e EB f a c i l i t y .

Chromium dioxide is very sens i t i ve t o the h i g h temperatures which were required t o form r ig id disk configurations. Room temperature EB curing permits the greater use of t h i s special magnetic pigment and a processing speed of 500 t o 1000 f e e t per minute a t 5 t o 10 Mrad energy dose requirements (Figure

0

e

4-30). (105) -

4-62

Glass -- Preform

-. .. . .. -. . . . . . . . . Furnace /

c3 vDiameter Monitor

Coating Material Coating Applicator

I o n I

UV-Curing Lamp System I I I I

I

Coated and Cured Fiber t- Figure 4-29. U V Coating o f Optical Fibers (103)

4-63

I m P

Unwind Rewind

Figure 4-30. Magnetic Media Coating Line w i t h EB Cure (105)

O p t i c a l Media. r a t i o n o f s o p h i s t i c a t e d o p t i c a l m a t e r i a l s and systems i n e l e c t r o n i c dev i ces f o r t h e

communications and home market p roduc t areas. These dev ices i n c l u d e l a s e r - r e a d a b l e

v i d e o i n f o r m a t i o n c a r r i e r s (Laser V i s i o n ) , l a s e r - r e a d a b l e audio i n f o r m a t i o n c a r -

r i e r s (Compact D i s c ) , da ta s to rage f o r computer a p p l i c a t i o n s ( d i g i t a l o p t i c a l

r e c o r d i n g ) , compound Senses o r a s p h e r i c a l lenses ( o p t i c a l l e n s e s ) , and o p t i c a l da ta

t r a n s p o r t systems ( o p t i c a l f i b e r s and waveguides). The advantage o f o p t i c a l sys-

tems over t h e i r meta l conductor analogs can be shown i n Table 4-21. (106) The

- ___ - o p t i c a l dev ices have a much g r e a t e r f requency range- t ransmiss ion c a p x i t y w i t h v e r y

low l o s s of a t t e n u a t i o n p r o p e r t i e s when compared w i t h o t h e r methods used f o r d i r e c t

s i g n a l coup1 i n g o f e l e c t r o n i c i n f o r m a t i o n .

Recent developmcnts i n l a s e r technology have l e d t o t h e i n c o r p o -

__

Table 4-21

COMPARISON OF VARIOUS MEANS OF TRANSMISSION (106)

Transmiss ion Type Frequency Range (kHZ A t t e n u a t i o n (dB/km)

Wire P a i r 1-140 0.1-0.3 Coaxi a1 Cable

Waveguide

O p t i c a l F i b e r

0.06-51 x 10' - <50 x lo6

l o l l

59 0.5-4

<1 .O-800

One o f t h e most i m p o r t a n t new areas o f o p t i c a l r e l a t e d communication dev ices i s t h e

o p t i c a l " v ideo d i s c " .

and sound i n f o r m a t i o n i s reco rded on i t as a success ion o f sma l l depress ions o f

v a r i a b l e l e n g t h and r e p e t i t i o n f requency.

a helium-neon l a s e r (632.8 nm) b y t h e p l a y e r i n such a manner t h a t t h e read-out

system does n o t come i n d i r e c t p h y s i c a l c o n t a c t w i t h t h e d i s c . The o p t i c a l d i s c

i s manufactured i n t h e f o l l o w i n g manner:

About t h e s i z e o f a l o n g - p l a y i n g audio reco rd , t h e p i c t u r e

The i n f o r m a t i o n i s sensed o p t i c a l l y w i t h

0 P r e p a r a t i o n o f a me ta l master mold ( u s i n g p h o t o r e s i s t o r photo1 i t h o g r a p h i c p rocess ing techniques 1.

A p p l i c a t i o n o f a UV-curable c o a t i n g o r adhesive t o t h e c e n t e r of t h e me ta l mold.

0

0 Deformat ion ( s l i g h t bending) o f a t r a n s p a r e n t p l a s t i c d i s c (polymethylmethacrylate, p o l y v i n y l c h l o r i d e , o r po l yca rbona te ) t o make i t convex, and a p p l i c a t i o n o f t h e r a d i a t i o n c u r a b l e adhesive f o r u n i f o r m spreading over t h e me ta l master mold su r f ace.

4-65

a Exposure o f t h e r a d i a t i o n - c u r a b l e c o a t i n g o r adhesive t o UV l i g h t (365 nm) and p o l y m e r i z i n g t h e l i q u i d system i n t o a r i g i d f i l m .

a Separa t i on o f t h e s u b s t r a t e and cured c o a t i n g f r o m t h e mold f o l l o w e d by m e t a l i z a t i o n ( m i r r o r f o r m a t i o n ) and f i n a l c o a t i n g (UV r a d i a t i o n cu rab le , plasma coa t ings o r conven t iona l low- temperature a i r dry-cured c o a t i n g system) f o r p r o t e c t i o n f r o m ab ras ion and h a n d l i n g opera t i ons .

A d iagram d e p i c t i n g t h e major o p e r a t i o n s assoc ia ted w i t h v ideo d i s c manufacture i s shown i n F i g u r e 4-31.

present-day v i d e o d i s c s can be u t i l i z e d f o r f u t u r e manufacture o f new o p t i c a l

r e c o r d i n g systems and dev ices. (107,108)

Many o f t h e r a d i a t i o n p rocess ing concepts developed f o r __ _. . _. -. -

PLASTICS AND RUBBER MATERIALS

Cur ren t r a d i a t i o n p rocess ing o f p l a s t i c s i s m a i n l y i n v o l v e d w i t h h i g h energy

e l e c t r o n - i n d u c e d c r o s s - l i n k i n g of p o l y e t h y l e n e and p o l y v i n y l c h l o r i d e f o r foam

s t a b i l i z a t i o n , w i r e i n s u l a t i o n , and heat s h r i n k a b l e f i l m s o r t u b i n g a l though o t h e r

v i n y l t ypes of polymers can a l s o be c r o s s - l i n k e d i n a s i m i l a r manner t o produce

u s e f u l p roduc ts (Tab le 4-22 1.

High energy e l e c t r o n r a d i a t i o n p rocess ing i s used i n t h e w i r e and c a b l e i n d u s t r y t o

improve t h e p r o p e r t i e s of t h e i n s u l a t i n g p l a s t i c m a t e r i a l s .

b e n e f i t s o f r a d i a t i o n p rocess ing i s t h e i nc reased thermal s t a b i l i t y and toughness

o f t h e i r r a d i a t e d polymer over t h a t o f a conven t iona l u n c r o s s - l i n k e d i n s u l a t i o n

m a t e r i a l (Tab le 4-23). The most i m p o r t a n t f e a t u r e assoc ia ted w i t h h igh-energy

e l e c t r o n r a d i a t i o n p rocess ing o f w i r e and c a b l e i n s u l a t i o n m a t e r i a l s i s t h e f a c t

t h a t t h e depth o f e l e c t r o n p e n e t r a t i o n i n a g i v e n i n s u l a t o r i s a d i r e c t f u n c t i o n o f

e l e c t r o n energy and i n v e r s e l y r e l a t e d t o t h e s p e c i f i c g r a v i t y o f t h e m a t e r i a l . For example, a 0.020 - i n c h t h i c k n e s s o f r a d i a t i o n c u r a b l e PVC hav ing a s p e c i f i c g r a v i t y

v a l u e o f 1.3 would r e q u i r e 200 kV o f e l e c t r o n energy f o r f u l l p e n e t r a t i o n ; a 0.045-

i n c h t h i c k sample would r e q u i r e 500 kV f o r p e n e t r a t i o n ; and a 0.090-inch t h i c k

sample o f t h e same m a t e r i a l would r e q u i r e 1 MeV. The i n v e r s e r e l a t i o n s h i p between

s p e c i f i c g r a v i t y and depth o f e l e c t r o n p e n e t r a t i o n a t cons tan t v o l t a g e i s shown i n Table 4-24. A t y p i c a l e lectron-beam p rocess ing s e t up f o r w i r e l c a b l e i s shown i n

F i g u r e 4-32. Th is t y p e o f r a d i a t i o n p rocess ing o p e r a t i o n can m o d i f y w i r e p roduc ts a t speeds o f 500 t o 3,000 f t l m i n ( s i x EB a c c e l e r a t o r s can manufacture 5.23 b i l l i o n

f t l y e a r based on speeds o f 12,000 f t l m i n , 22 h r l d a y f o r 330 d a y l y r ) w i t h 10 t o 20 mA beam c u r r e n t s o r dose va lues r a n g i n g from 1 t o 10 Megarads.

i n s u l a t i o n can a l s o be c r o s s - l i n k e d c h e m i c a l l y through t h e use of perox ides, mois-

One o f t h e major

Wire and cab le

4-66

MO

MO

MO: Mold; L: Liquid Layer; S: Substrate; M: Mirror; P: Protective Layer.

Molding

Exposure

Separation

Imaging

F i g u r e 4-31. F a b r i c a t i o n of L a s e r v i s i o n Video D iscs (107,108)

4-67

Table 4 - 2 2

SELECTED APPLICATION AREAS FOR IRRADIATED POLYMER MATERIALS (109)

Pol Ymers

Polyethylene

Polyvinyl chlor ide

Propropyl ene Polyamide Polyvinyl idene f luor ide Ethylene fluorocarbon copolymer F1 uoropolymer Ethyl vinyl ace t a t e Thermoplastic polyimide Chlorinated polyethylene Neoprene Butyl Si1 icone elastomer F1 uoroel astomer Ethyl ene propylene rubber Polyurethane

ADD1 i c a t i ons

Hookup wire Automotive wire Appliance and fixture wire Business machine wire Computer control cabl e Nuclear power s t a t ion control cable Low voltage power cable Aircraf t and aerospace wire

Hookup wire F1 a t ribbon cabl e High voltage lead wire Computer back panel wire Tel ephone wire Motor lead wire

Shrinkable tubings Shrinkable pa r t s Shrinkable tapes Die lec t r ic rod and sheet forms Wire insulat ion and jacket ing

4-68

Table 4-23

COMPARISON OF PHYSICAL PROPERTIES FOR CONVENTIONAL 105O C PVC AND IRRADIATED PVC WIRE COMPOUNDS (109)

Phys ica l P r o p e r t v

T e n s i l e s t r e n g t h

E l ongat i on -~

S o l d e r i r o n r e s i s t a n c e : Time t o f a i l @ 660° F, 1.5 l b . l o a d

I n s u l a t i o n r e s i s t a n c e : Megohms/l ,000 ft . C u t - t h r u r e s i s t a n c e : Time t o c u t - t h r u @ 105O C, .005" c h i s e l

Heat r e s i s t a n c e : % r e t e n t i o n o f e l o n a t i o n a f t e r 168 h r s @ 136 % C

Convent ional 105O C PVC P r o p e r t y Values

3,000 p s i

250%

t l second

>1,000

<5 seconds

50

I r r a d i a t e d PVC P r o u e r t v Values

3,000 p s i

200%

>300 seconds

>1,000

>600 seconds

75

4-69

Table 4-24

EFFECT OF SPECIFIC GRAVITY OF A MATERIAL ON THE DEPTH OF ELECTRON BEAM PENETRATION AT TWO ELECTRON ACCELERATOR VOLTAGES

(0.3 AND 1 MeV) (109)

S p e c i f i c G r a v i t y

1 .o 1.3

Accel e r a t o r Voltage (MeV)

1

1

Depth of Beam Penet ra t ion ( inches 1

0.12

0.09

1.8

1 .o 1.3

1.8

1

0.3

0.3

0.3

0.06

0.04

0.03

0.02

4-70

Electron Scanner

Wire In

Wire Out

Electron Beam ;

Side View

Electron Scanner

Wire Out

Wire In I U U

Top View

Figure 4-32. W i re-Cab1 e (109)

Electron-Beam Processing System f o r

4- 71

t u r e , and thermal (steam o r d r y n i t r o g e n ) p rocess ing manufactur ing equipment.

There are seve ra l d i s t i n c t advantages t o t h e h igh-energy e l e c t r o n r a d i a t i o n process

over those assoc ia ted w i t h conven t iona l thermal c u r i n g techniques, b u t t h e r e a r e no

i n s u l a t i o n t h i c k n e s s r e s t r i c t i o n s w i t h t h e conven t iona l system as i s t h e case f o r

r a d i a t i o n p rocess ing techno log ies (Table 4-25).

Two o t h e r areas o f i n t e r e s t i n v o l v i n g commercial r a d i a t i o n p rocess ing o f p l a s t i c s

m a t e r i a l s a re c r o s s - l i n k e d p o l y e t h y l e n e foams and sh r inkage packaging m a t e r i a l s o r

t u b i n g ( p o l y o l e f i n s ) f a r faod and w i r e connector a p p l i c a t i o n s .

C r o s s - l i n k e d p o l y e t h y l e n e foams a re u s u a l l y expanded 10 t o 40 t imes t h e i r o r i g i n a l

volume; t h e y a re manufactured b y bo th e l e c t r o n beam i r r a d i a t i o n and chemical

c r o s s - l i n k i n g methods. These m a t e r i a l s have d e s i r a b l e q u a l i t i e s f o r commercial use

because o f t h e i r r e s i l i e n c y , c l o s e d c e l l c o n s t r u c t i o n , and t h e i r a b i l i t y t o be

thermofonned i n t o a wide v a r i e t y o f shapes and c o n f i g u r a t i o n s .

( c r o s s - l i n k e d and nonc ross - l i nked ) i s a s p e c i a l t y polymer w i t h a usual consumption

of about 25,000 m e t r i c tons; consumption i s growing a t an annual r a t e o f about

15 percent .

t o t a l commercial p o l y e t h y l e n e foam market. H a l f o f t h i s c r o s s - l i n k e d foam i s made

th rough t h e use o f i o n i z i n g r a d i a t i o n f rom e l e c t r o n a c c e l e r a t i o n i n t h e 500 kV t o 4

MeV range; t h e o t h e r h a l f uses o r g a n i c pe rox ides . Both techn iques a re growing i n

use more i n accordance w i t h t h e f e a t u r e s o f t h e foaming process r a t h e r than t o t h e

method o f c r o s s - l i n k i n g manu fac tu r ing p rocess ing opera t i ons . These foam m a t e r i a l s

a r e used f o r gaskets , f l o o r back ing, mount ing tapes, and consumer goods such as

e x e r c i s e o r camping mats, t oys , l i n e r s , b r a cups, and o r t h o p e d i c suppor t

m a t e r i d l s . (110)

Po lye thy lene foam

The c r o s s - l i n k e d polymer comprises approx ima te l y 50 p e r c e n t o f t h e

The CRYOVAC D i v i s i o n o f W. R. Grace and Company manufactures r a d i a t i o n processed

hea t -sh r inkage p l a s t i c f i l m s and bags f o r t h e vacuumized packaging o f f o o d prod-

u c t s . I n t h i s techno logy a p o l y o l e f i n preform o r tube i s ext ruded, then i r r a d i a t e d

w i t h h igh-energy e l e c t r o n s (500 kV t o 2 MeV scanning e l e c t r o n beam processor, 25 mA beam c u r r e n t s , 18 i n c h sweep pa th ) , b i a x i a l l y o r i e n t e d v i a a blown f i l m - t r a p p e d

bubble process, and made i n t o bags o r s l i t and s o l d as f i l m . f i n s have a memory e f f e c t such t h a t upon h e a t i n g t h e f i l m o r t u b i n g s h r i n k s causing

a secure f i t around p roduc ts con ta ined w i t h i n i t s surfaces. s i m i l a r process f o r i r r a d i a t i n g p o l y o l e f i n t u b i n g f o r connec t ing w i r e s o r a p p l y i n g

permanent mark ing l a b e l s t o w i r e end connectors v i a hea t sh r ink ing -bond ing

techniques. (111)

I r r a d i a t e d p o l y o l e -

Raychem developed a

4-72

Table 4-25

COMPARISON OF CHEMICAL VULCANIZATION VERSUS IRRADIATION PROCESSING (2)

Chemical Vu 1 cani zat i on

$150,000 installation cost-less, if boiler avai 1 able

Special extrusion equipment required

Irradiation Processina

$150,000 installation cost, turnkey avai 1 able

No special extrusion equipment

Critical extrusion conditions Noncritical extrusion conditions

High-pressure steam and cooling auxi 1 i ari es

No auxiliary requirements: integrated system

High scrap on start-up Economi c a 1 start-up

Low-to-medium speed, no wall thickness limitation

Space-consuming 300-500 ft steam and cooling troughs

Heat , steam environment/ safety factors

High-speed, wall thickness limitation

Compact, no troughs

Ozone , irridati on environmental/ safety factors

4-73

High-energy e l e c t r o n r a d i a t i o n processes can a l s o be used t o improve t h e p r o p e r t i e s o f e l a s t o m e r i c o r rubber m a t e r i a l s used i n t h e manufacture o f conveyor b e l t s ,

rubber c a b l e i n s u l a t i o n , and t i r e s . (112) - The g r e a t e s t volume use o f r a d i a t i o n

( e l e c t r o n beam) p rocess ing technology i s i n t h e t i r e i n d u s t r y , which consumes most

of t h e n a t u r a l l y o c c u r r i n g and s y n t h e t i c e lastomers produced i n t h e U.S. t oday (Tab le 4-26). (113) -

-

~

~

I n t h e t i r e manu fac tu r ing process t h e i n n e r l i n e r s , body p l i e s , t r e a d s t a b i l i z e r

p l i e s , s i d e w a l l s , and o t h e r t i r e components can be i r r a d i a t e d w i t h h igh-energy

e l e c t r o n s p r i o r t o t h e i r assembly i n t o t h e t i r e .

t rea tmen t improves t h e f o r m s t a b i l i t y o f t hese m a t e r i a l s d u r i n g t h e c o n s t r u c t i o n ,

mold ing, and subsequent thermal v u l c a n i z a t i o n o r c u r i n g o f t h e t i r e composi te system. The i r r a d i a t i o n process improves gage r e t e n t i o n o f t h e t i r e components i n

t h e f i n a l p roduc t such t h a t an o v e r a l l r e d u c t i o n i n t h i c k n e s s o f one o r more o f t h e

f u n c t i o n a l l a y e r s can be achieved. This equates t o an o v e r a l l sav ings i n m a t e r i a l s

and p rov ides an economic i n c e n t i v e f o r t h e use o f i r r a d i a t i o n p o s t t r e a t m e n t o f

ca lendered o r ex t ruded p a r t s o f t h e t i r e .

of e lastomers f o r improved t i r e and r e l a t e d p roduc ts a re shown i n Table 4-27. (112) -

The c r o s s - l i n k i n g induced b y t h i s

F u r t h e r examples o f r a d i a t i o n t rea tmen t

PLASMA PROCESSING

Low-temperature plasma r a d i a t i o n i s a new t o o l f o r t h e commercial p rocess ing o f

polymer p roduc ts . Plasma-processing o f f e r s a c lean, f a s t , and s a f e method o f p re -

p a r i n g polymer su r faces f o r bonding, p r i n t i n g , p o t t i n g , c o a t i n g , and m e t a l i z i n g .

Convent ional methods f o r p r e p a r i n g polymer su r faces can be d i v i d e d i n t o two ca te - g o r i e s :

contaminants f o l l o w e d b y t r e a t m e n t w i t h a chemical t h a t e tches o r o x i d i z e s t h e

polymer su r face . Dry processes i n c l u d e t h e use of corona d ischarges, gas f lames,

and mechanical ab ras ion t o a l t e r a polymer surface. A l l o f t hese c u r r e n t t ech -

n iques have c e r t a i n drawbacks (hazardous, l i m i t e d usefu lness, o r r e s t r i c t e d t o

c e r t a i n polymer c l a s s e s ) which can many t imes be overcome through u t i 1 i z a t i o n o f

p lasma-processing techno log ies . A comparison o f plasma e t c h i n g o f polymer su r faces

w i t h o t h e r methods o f polymer s u r f a c e m o d i f i c a t i o n s w i t h rega rd t o adhesive bond

s t r e n g t h development i s shown i n Table 4-28. (119) -

wet and d ry . Wet p rocess ing uses a s o i v e n t t o remove grease and o t h e r

4-74

Table 4-26

RUBBER MARKET DISTRIBUTION (113)

Products

T i r e s and t i r e p roduc ts

N o n t i r e products

Footwear

B e l t s , b e l t i n g

Hose, t u b i n g

Sponge rubber products

Foam rubber p roduc ts

F l o o r and w a l l c o v e r i n g

O-r ings, pack ing, gaskets P r e s s u r e - s e n s i t i v e tape

I n d u s t r i a l r o l l s

Automot ive molded goods

Other molded goods

M i 1 i t a r y goods

Shoe p roduc ts

Drugs, medica l sundr ies

Coated f a b r i c s

Thread ( b a r e )

Sol ven t and 1 a tex cement

Toys, b a l l oons

A t h l e t i c goods

Wire, c a b l e

Other

T o t a l n o n t i r e p roduc ts

Percent

65

. _ . 1 1 2

1.1 3 0.4 2 0.6 0.6 5 6 0.5

1.6 0.5

1.3 0.5 1.5 0.4 0.6 1.1 4.3

35 100

4- 75

Table 4 - 2 7

APPLICATIONS FOR RADIATION PROCESSED ELASTOMERIC MATERIALS (112)

ADD^ i cat i on Irradiation of radial body plies with 500 KeV electrons to doses between 1 and 5 M rads in combination with radial tensile strains o f 1 to 7 percent applied during single stage ex- pansion of a tire eliminated wrinkling or waviness of the reinforcing tire cords.

Irradi at i on of i nnerl i ners, pl ies, bead cores and treads improves the dimensional stabil ity of the above tire components.

Extrusion of rubber strips into a moving mold followed by embossing a design in the rubber then stripping it from the mold and irradiate to produce a product useful in floor mats or precured treads useful in retreading of tires.

Radiation induced degradation of multilayer ti re rubber (polyi sobutyl ene) inner1 i ners combined with other materials to produce puncture sealant composite structures.

Reduction of unsightly rubber projections such as vents and flash materials on the surface of cured tires through the use of irradiation of the tire surface prior to molding and curing. The radiation post- treatness process also demonstrated a 2 to 9 percent increase in wet and dry skid res i stance of ti res.

Reference

114

115

116

117

118

4-76

Table 4-28

RELATIVE ADHESIVE BOND STRENGTHS FOR PLASMA AND CONVENTIONAL METHODS OF TREATING POLYMER SURFACES (2)

~ T reatment Process and Re1 a t i v e Bond S t r e n g t h Polymer Con t ro l Plasma Abrasion Corona Chemical

Po lye thy lene 1 12.1 -- 4.5 5.1

- Po lyp ropy lene ___. __ _.. 1 221 -- 81 649

1 P o l y e s t e r 1 19 3 --

Plasma polymer ized o rgan ic coa t ings e l i m i n a t e many of t h e problems assoc ia ted w i t h

c o n v e n t i o n a l t h e r m a l l y cured c o a t i n g systems ( s o l v e n t removal , excess thermal ene rg ies , e t c . ) and have unique p r o p e r t i e s such as v e r y h i g h chemical and ab ras ion

r e s i s t a n c e ( h i g h degree of c r o s s - l i n k i n g ) , cont inuous o r p i n - h o l e f r e e f i l m s t r u c t u r e s , m u l t i l a y e r f i l m s w i t h v a r y i n g i n d i c e s o f r e f r a c t i o n ( a n t i g l a r e

c o a t i n g s ) , t h i n membrane and b a r r i e r f i l m s t r u c t u r e s , d i e l e c t r i c f i l m s , and b lood

compa t ib le f i l m s f o r b iomedica l a p p l i c a t i o n s ( F i g u r e 4-33). Some r e p r e s e n t a t i v e

o r g a n i c s t a r t i n g m a t e r i a l s and t h e i r r e s u l t a n t plasma polymer ized f i l m s t r u c t u r e s

and a p p l i c a t i o n s a re shown i n Table 4-29. (46,120-122)

Table 4-29

PLASMA COATINGS (46)

Trea ted i n Plasma

T e t r a f l u o r o e t h y l e n e

Hexamethy ld is i loxane, t e t r a e t h y l t i n and oxygen

Benzoni tr i 1 e

R e s u l t a n t Polymer

Thin d i e l e c t r i c f i l m s on meta l s u r f aces f o r c a p a c i t o r a p p l i c a t i o n s

Abras ion r e s i s t a n c e , l o w mois- t u r e p e r m e a b i l i t y and a n t i - r e f l e c t i o n p r o p e r t i e s

Membrane s t r u c t u r e s on s i 1 i cone-po lyca rbona te f i l m s f o r gas s e p a r a t i o n processes

References

120

121

12 2

4-77

~

-

CONTROLLED

THERMAL STABILITY BARRIER

PROPERTIES SURFACE TREATMENTS

AND COATINGS FOR PLASTICS ELASTOMERS GLASSES

CERAMICS ADHESION PROMOTION

CONTROLLED LIGHT WETTABILITY TRANSMISSIVITY

COMPATIBILITY

Figure 4-33. Applications of Plasma Processing Technologies

4-78

Sec t ion 5 COST AND ENERGY S A V I N G S COMPARISONS

I n o rde r t o p r o j e c t t h e f u t u r e usage o f r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s

i t i s necessary t o compare t h e c o s t and p o t e n t i a l energy sav ings o f t h i s technology w i t h t h a t o f c o m p e t i t i v e m a t e r i a l s p rocess ing a l t e r n a t i v e s f o r a g i v e n s e t o f mar-

k e t o r a p p l i c a t i o n areas.

an impact must a l s o be examined.

p a r i s o n f o r each of t h e major a p p l i c a t i o n s o f r a d i a t i o n p rocess ing i s discussed.

I n a d d i t i o n , changes i n technology which c o u l d have

I n t h i s s e c t i o n , a c o s t and energy sav ings com-

d iscussed i n S e c t i o n 6. Techno1 o g i c a l f a c t o r s a f f e c t i n g market p r o j e c t i o n s a re

COST COMPARISON - RADIATION PROCESSING VERSUS THERMAL PROCESSING TECHNOLOGIES

When a n a l y z i n g t h e c o s t of c o m p e t i t i v e p rocess ing ( c u r

po l ymer i c m a t e r i a l s seve ra l f a c t o r s must be cons ide red

f o l l o w i n g :

Cost o f equipment

Cost o f f u e l l e l e c t r i c i t y (energy sav ings )

E f f i c i e n c y o f equipment

ng o r c r o s s - l i n k

These f a c t o r s

Scrap losses i n t h e process

Labor and f l o o r space requi rements

P roduc t i on r a t e s and a b i l i t y t o e l i m i n a t e h a n d l i n g opera t i ons ; c a p a b i l i t y f o r complete automat ion

Cost of po l ymer i c m a t e r i a l s ( c o a t i n g s ) undergoing t h e process- i n g o p e r a t i o n

Environmental f a c t o r s ( r a d i a t i o n s h i e l d i n g , po l 1 u t i o n 1.

n g ) of nc lude t h e

A l l o f t h e f a c t o r s assoc ia ted w i t h c o s t comparisons between conven t iona l g a s - f i r e d

ovens and v a r i o u s t ypes o f r a d i a t i o n p rocess ing equipment are bes t desc r ibed by t h e

f o l l o w i n g examples f o r each o f t h e major market areas desc r ibed i n t h i s r e p o r t . (123)

5-1

Coat ings

The use o f r a d i a t i o n c u r a b l e coa t ings i s a s i g n i f i c a n t a l t e r n a t i v e f o r t h e reduc-

t i o n o f energy consumption and compl iance w i t h a i r p o l l u t i o n l e g i s l a t i o n f o r t h i s

i n d u s t r y . The c o s t comparison and energy e f f i c i e n c y da ta f o r p r o c e s s i n g o f a wood

f i l l e r v e h i c l e u s i n g UV and i n f r a r e d p rocess ing equipment i s g i v e n i n Table 5-1.

The UV processor and assoc ia ted c o a t i n g system r e s u l t i n lower p r o d u c t p r o d u c t i o n

c o s t s w i t h a s u b s t a n t i a l sav ings i n energy over t h e thermal c u r i n g c o a t i n g opera-

t i o n . The o v e r a l l power consumption c o s t s pe r square f o o t o f p r o d u c t a r e app rox i -

m a t e l y 0.1 f o r t h e UV system, and 0.2 f o r t h e I R system. (123,124)

One o f t h e major commercial successes i n r a d i a t i o n p rocess ing over t h e thermal

p rocess ing techniques f o r c o a t i n g s and i n k s has been demonstrated by t h e can indus -

t ry. I n t h e U.S., Adolph Coors Company and American Can Company have been t h e l e a d e r s i n u t i l i z a t i o n o f UV c u r a b l e i n k s and o v e r p r i n t va rn i shes f o r beer and

beverage can p roduc ts . Coors has r e p o r t e d t h a t 246% more energy i s r e q u i r e d t o

t h e r m a l l y c u r e conven t iona l s o l v e n t o r water-based i n k s or c o a t i n g s t h a n t o c u r e

u l t r a v i o l e t s e n s i t i v e i n k s and coa t ings . A t y p i c a l can l i n e ( F i g u r e 4-5) o p e r a t i n g a t 600 t o 2000 cans/min on a 7 hr /day, 250-day work y e a r u s i n g a UV d r y e r would save

over 1 b i l l i o n B t u a year w i t h an approximate p r o d u c t i o n r a t e o f over 63 m i l l i o n

beer cans annua l l y .

thermal d r y i n g o f i n k s and c o a t i n g s based on Coors exper ience i s g i v e n i n Table

5-2.

b i l l i o n B t u saved i n go ing f r o m n a t u r a l g a s - f i r e d ovens t o UV r a d i a t i o n p rocess ing

equipment) w i t h UV c u r a b l e i n k s and c o a t i n g s i n a system c o m p l e t e l y d i f f e r e n t i n

c h e m i s t r y than t h a t o f t h e Coors c o a t i n g .

t h rough a f r e e r a d i c a l mechanism; t h e American Can c o a t i n g system i s cu red through

a photo induced c a t i o n i c r i n g opening epoxy r e s i n r e a c t i o n mechanism. (53,54,124)

An e s t i m a t e o f energy sav ings and comparison o f UV versus

American Can Company has had s i m i l a r energy sav ings exper ience (ove r 100

The Coors c o a t i n g system i s cu red

Table 5-3 summarizes d a t a f r o m a h y p o t h e t i c a l c o s t model assoc ia ted w i t h t h e use o f

a thermal oven, an e l e c t r o n c u r t a i n processor , and a UV c u r i n g chamber. (125) - Each system i s designed t o process 180 m i l l i o n square f e e t o f aluminum c o i l s t o c k per y e a r (1 m i l t h i c k c o a t i n g ) a t l i n e speeds of up t o 150 f e e t per m inu te . I n t h i s model t h e h o u r l y p rocess ing c o s t s and c o s t per square f o o t o f p r o d u c t produced f o r t h e c o n v e n t i o n a l thermal c o a t i n g / c u r i n g o p e r a t i o n a re approx ima te l y t w i c e those o f

e i t h e r r a d i a t i o n process. Coat ing m a t e r i a l c o s t s assoc ia ted w i t h t h i s model a r e app rox ima te l y 1.18 cents /square f o o t f o r a conven t iona l so

a l k y d v a r n i s h . T h i s i s app rox ima te l y e q u i v a l e n t t o a 100%

c o s t i n g 1.17 c e n t s t o 1.19 cents /square f o o t . A more de ta

vent-based (35% s o l i d s )

s o l i d s EB/UV v a r n i s h

l e d and complete analy-

5-2

Table 5-1

UV AND IR PROCESSING COST AND ENERGY EFFICIENCY DATA (123)

Oven length (ft)

Line speed (fpm)

Wood filler vehicle

Nonvolatile (%)

Film thickness (mils)

Coverage (wet) (sq ft/gal)

Coats

Cure time (sec)

Exit temp (OF)

coo 1

Cost of filler ($/gal)

Cost per sq ft (6) Per coat Total

Power (kw)

Power per sq ft ($)

Surface appearance

Hardness

Sand i ng

Typical UV Typical I R

10-30

60-150

Po 1 yes ter

90- 100

2

700-800

1

10

100

No

5.00-6.00

0.7-0.9 0.7-0.9

100

Less than 0.1

Ex (one coat)

Ex

Ex

90

60

Urea-A1 kyd

35-65

2

500

2

90

130

Yes

2 00-3 00

0.9-1.3 1.8-2.6

250

App. 0.2 (two coats)

G (two coats)

G

VG

Ex = excellent, G = good, VG = very good

5-3

Gas

Table 5-2

COMPARISON OF UV VERSUS GAS FIRED THERMAL CURE COATING/INK SYSTEMS FOR BEVERAGE CONTAINERS (53)

pment Costs

Costs ($0.43/1000 ft3) -

Electrical Costs ($O.Ol/KWH) -

Energy and Maintenance Costs -

Ink Costs -

Sol vent Emissions

F1 oor Space Requirements

Gas fired more than

The aas f

ovens cost 2.5 times a UV processor

red w e n requires 4,OOi,OOO BTU/hr while the UV processor uses no gas

UV requires 22 KWH, the gas fired oven require 15 KWH

Gas fired ovens have 2-3 times the energy and maintenance cost of a UV processor

UV inks are between 1.1 and 1.75 times more expensive than conventional thermal curing ink systems

UV has no solvent emissions while the thermal cure inks release at least 20% of their weight

Gas fired ovens require 10 times the space as the UV processor

5-4

Table 5-3

OPERATING COST ANALYSIS FOR RADIATION VERSUS THERMAL PROCESSING EQUIPMENT FOR COATING ALUMINUM COIL STOCK (125)

Purchase P r i c e Pol 1 u t i on Contro l Equipment Maintenance Gas E l e c t r i c i t y Labor F1 oor Space

Tota l

Thermal Oven,

200,000

7,500 2 , 000

23, OOOa 8,700b

108,0OOc 3,000

172,000

E lec t ron Cur ta in , A 210,000

- - 1 , 000 8, OOOd 3,000

72,000 3 50

105,350

8 Lamp UV Processing

300 watts/ inch,

80,000.

- - 2, oooe - -

9,600 72.000

300 91,900

Hour ly Processing Costs 43.05 26.34 22.98 (4000 hours/year)

Processing Costs cents/square foo t

0.120 0.073 0.064

Processing Parameters: 180 m i l l i o n square feet /year a t 150 feet/minute w i t h a coat ing th ickness o f 1 m i l .

“14.4 MSCF a t $l.GO/MSCF. b290 MKWH a t $0.03/KWH. c1.5 people a t $18/hour. d I n e r t i n g gas generator. e I n c l udes one complete change o f 1 amps a f t e r 2000 hours.

5- 5

s i s fo r coi l coating systems i s contained in reference 126 and a summary of these r e s u l t s i s shown in Tables 5-4 and 5-5.

- The curing of c lear and pigmented coatings on p l a s t i c subs t ra tes i s an area where radiat ion processing techniques have a d i s t i n c t advantage over conventional thermal curing methods. Table 5-6 describes three curing methods ( E B , U V , and gas-fired ~

ovens) fo r processing coatings on p l a s t i c subs t ra tes . The par t icu lar advantage of radiat ion (E6 or U V ) curing over the thermal curing process is the very short exposure times fo r the radiatiom systems over those of the conventional ttiermal cur - ing process. s t r a t e during the coating/curing process can lead t o h i g h scrap losses , and infer -

ior qua l i ty in the f inished product. (123)

The high heat-long exposure times experienced by the p l a s t i c sub-

These examples o f comparative processing methodologies for the coatings industry a l l tend t o show tha t a substant ia l cost and energy s a v i n g s can be real ized w i t h U V / E B and even IR radiat ion processing equipment over t ha t of conventional gas-- f i r e d ovens.

Printing Inks

The advantages fo r using u l t r av io l e t radiat ion processing equipment ra ther than a conventional e l e c t r i c dryer system fo r the pr int ing ink industry can be outlined as follows:

0 UV-radiation processing equipment has a lower purchase pr ice and can o f fe r short-term payback on i t s investment.

In s t a l l a t ion costs are usually lower and the required f loo r space f o r U V equipment i s much smaller than conventional e l e c t r i c dryer ovens.

0 Energy consumption is lower, resu l t ing in a reduced unit-product cos t .

0 U V inks have high f l a sh points and are 100% react ive so l id s ; t h u s , there

0

are no f i r e hazards, no emissions, no odors. Insurance costs are reduced and pollution control devices are not required.

Two U V curable ink l i nes will service 70 t o 80% o f the stock in a general screen-printing s h o p , and when the inks are cured they will n o t smear or bleed in to the product p i l e . T h i s el iminates special racking or handling procedures and stock wastage i s reduced.

0 UV inks are s t ab le on the press and allow fo r easy clean-up a f t e r the run i s f in i shed .

0

0 UV inks allow fo r rapid product processing and f a s t del ivery of product.

5 -6

Table 5-4

COMPARISON OF ENERGY REQUIREMENTS FOR DIFFERENT ENERGY SOURCES ON A MODEL COIL COATING LINE (1261

MMBtu Rlequired per Hour (Energy Consumption)

Peak Oven Peak Metal Sol vent Energy Source Coating Temperature Temperature Metal Evaporation A i r Other To ta l

Conventional f o s s i l 55% s o l i d s 660 F 450 F 0.699 Ignored 3.682 0.880 5.261 I f u e l (A.D. L i t t l e ( so l vent based cn

v Model System 1

I R Heaters 55% s o l i d s 300 F 450 F 0.699 0.1 -- 3.66 4.46 ( s o l vent based 1

I R Heaters 55% s o l i d s -- 300 F 0.426 0.282

Induc t i on Heating -- -- 450 F ----- Not Broken Dow

E lec t ron Beam or 100% s o l i d s None None None None E l e c t r o c u r t a i n

(water based -- 3.23 3.94

by Source---- 3.4

None -- 0.25

Table 5-5

COMPARATIVE COST ANALYSIS FOR H I G H ENERGY ELECTRON CURED COATING SYSTEMS VERSUS CONVENTIONAL THERMALLY CURED

COATING SYSTEMS ON ALUMINUM COIL STOCK (126)

Curing Method

Therm a 1

Thermal

Thermal

High Energy E l e c t r o n

Tot81 Energya T o t a l Gas Cost Coating System Af terburner 10 BTU/hr 1000 c f h _(__ $/hr

Hydrocarbon so l vent No preheat 15.7 15.4 40.03 (45% so l i d s 1 preheat 10.7 10.4 26.78

Water base (45% s o l i d s )

80% water I 2 0% alcohol (45% s o l i d s )

7.3 7 18.47

7.8 7.5 19.71

100% s o l i d s 0.85 0.4 2.27

aUsing 1 k W h r = 10,500 BTU f o r e l e c t r i c a l power: thermal energy conversion.

5-8

Capital cost ($)

Length (ft)

On-of f operation

Inert atmosphere

Cure temp. (OF)

Cure time

Cure coatings on plastics

Cure pigmented coatings

Require catalyst

Coating solids (%)

Coating coverage, sq ft/mil

Coating cost ($/gal )

Cost per mil sq ft

Hazard

Table 5-6

COMPARISON OF CURING METHODS (1 - 23)

EB

300 to 500K (H)

10-30

Yes

Yes

Ambient

1 sec or less

Yes

Yes

No

90- 100

700-1400

8 to 20 (H)

L-M

X-Rays

Ultraviolet

20 to l O O K (L)

10-30

Yes

No

100-200

Seconds

Yes

Sometimes

Yes

90-100

700-1400

8 to 20 (H)

L

uv

Oven

100 to 200K (M)

90-300

No

No

130+

Minutes

NO

Yes

Some t i mes

35-65

400-500

4 to 10 (L)

M

Heat

K = 1,000

Note: low(L), medium(M), high(H)

5-9

The model used f o r economic j u s t i f i c a t i o n o f pu rchas ing UV r a d i a t i o n p rocess ing

equipment over a conven t iona l e l e c t r i c d r y e r system i s shown i n Tab le 5-7. The model was based on a p r i n t i n g o p e r a t i o n capable o f r u n n i n g 2400 impress ions per

hour i n 250 days per year ( s i n g l e s h i f t ) and p roduc ing 29,880,000 square f e e t o f

product . The c o s t sav ings i n f a v o r o f t h e UV p rocess ing equipment was a p p r o x i -

m a t e l y $237,055.

compared t o a conven t iona l d r y i n g system, are s u b s t a n t i a l and i n c r e a s e as f u e l

c o s t s escal a te .

-

~

- Thus t h e b e n e f i t s t o be d e r i v e d f rom adop t ing a UV c u r i n g system,

The unique method o f p r i n t i n g rounded p l a s t i c c o n t a i n e r s ( F i g u r e 4-18) o f f e r s

an o p p o r t u n i t y t o make a d i r e c t comparison between two types ( l i n e a r and compact on

mandrel UV lamp c o n f i g u r a t i o n ) o f UV r a d i a t i o n p rocess ing equipment. The compari-

son o f annual o p e r a t i n g and p roduc t p r o d u c t i o n c o s t s f o r each system i s g i v e n i n

Tables 5-8 and 5-9. The n e t p roduc t p r o d u c t i o n r a t e f o r t h e compact UV lamp design i s 124,494,196 cups per year ( C P Y ) compared w i t h 93,363,000 CPY f o r t h e l i n e a r UV lamp p rocess ing u n i t . The annual c o s t sav ings f o r t h e manufacturer u s i n g t h e com-

p a c t UV d r y e r system i s $193,068. There i s a l s o a s u b s t a n t i a l sav ings on produc-

t i o n losses due t o f i r e s ( s t o p p i n g o f t h e l i n e , caus ing cups t o remain s t a t i o n a r y

under t h e h o t UV lamps) by u s i n g t h e compact UV lamp system r a t h e r than t h e l i n e a r UV d r y e r . (81 ) -

Adhes i ves

A c o s t comparison f o r thermal and e l e c t r o n beam c u r i n g o f adhesive systems i s g i v e n i n Table 5-10. I n t h e s tudy, a 60- inch thermal oven ( 6 MBtu/hour) , c o s t i n g

2 $160,000, p roduc ing 2,569 y d / h r o f adhesive coated p roduc t i s compared w i t h an

e l e c t r o n beam p rocess ing u n i t , c o s t i n g $200,000, and p roduc ing 3,400 y d / h r coated

p roduc t . (127) S i m i l a r r e s u l t s a re observed as those shown i n t h e c o a t i n g s i n d u s t r y

i n t h a t b o t h e l e c t r o n beam and UV p rocess ing u n i t s , f o r p ressu re s e n s i t i v e adhesive t a p e and l a b e l s , can reduce o p e r a t i n g and p roduc t manufactur ing c o s t s by as much as

50% (Tab le 5-11). (127)

2

E 1 ec t r on i c s /C omm un i c a t i on

Cost, energy sav ings, and p r o d u c t i o n r a t e comparisons f o r p roduc ts i n t h e e l e c -

t r o n i c s and communications i n d u s t r y processed by thermal o r r a d i a t i o n methods were

n o t a v a i l a b l e a t t h e t i m e o f w r i t i n g t h i s r e p o r t . I t shou ld be noted, however, t h a t many o f t h e p roduc ts assoc ia ted w i t h these i n d u s t r i e s can be manufactured

u t i l i z i n g a wide range o f r a d i a t i o n energ ies, as was p r e v i o u s l y desc r ibed f o r i n t e -

g r a t e d c i r c u i t s , p r i n t e d c i r c u i t boards, and e lec t romagne t i c r e c o r d i n g media a p p l i -

5-1 0

Table 5-7

COMPARISON OF DRYER PROCESSING COSTS FOR PRINTING APPLICATIONS (68)

Drver Costs

Purchase Price

Width (inches)

Processing Capacity (Impressions per Hour)

Floor Space (Square Feet)

Weight (Pounds)

Power Consumption (Ki 1 owat/Hours)

Power Supply (Volts A.C., Amps, Herz)

Ink Cost (Per Gallon)

Ink Cost (Per Square Feet)

Product Production Costs

Labor Cost

Materials and Floor Space Cost

Energy Cost

TOTAL OPERATING COSTS

Electric Drver

$38,000

38

2,800

225

4,000

30

2 40/ 1 20/60

$24

$0.015

$24,504

$5,520,861

$3,712

$5,552,077

UV Processing Eauipment

$18,800

38

3,600

50

1,500

15.2

2 4 0/6 O/ 6 0

$65

$0.017

$20,354

$5,293,028

$1,640

$5,315,022

5-1 1

Table 5-a

COMPARISON OF ANNUAL OPERATING COST, PRODUCTION AND COST SAVINGS BETWEEN A CONVENTIONAL UV LINEAR RADIATION

PROCESSOR AND A COMPACT ON-MANDREL UV PROCESSOR (81) -

Capi ta l (p r in te r /d ryer ) , 8% o f $115,000

Operator, $5 per hr. *

Floorspace, $3/sq. ft./yr.

Dryer E l e c t r i c a l , 3f#/KWH

Dryer Maintenance, $8/hr.

Dryer pa r t s

TOTAL COST

Conventional UV

$ 9,200

36,000

522

3,240

160

2,400

$ 51,522

Scheduled Hours

Hours l o s t t o causes o ther than dryer f a i l u r e

Hours l o s t t o f i r e s , jams 81 maintenance o f d ryer

Net Product ion Hours

7,200

720

50

6,430

P r i n t e r Speed

Loss Rate a t Transfers

Net Product ion Rate

CPM = Cups per min CPH = Cups per hour

Annual Product ion

CPY = cups per year

Sales Value o f Product ion a t $14/M cups

250 CPM 15,000 CPH

3.2% 480 CPH

14,520 CPH

93,363,000 CPY

$ 1,307,090

On-Mandrel UV

$ 9,200

36,000

192

1,188

64

600

$ 47,244

7,200

720

8

6,472

325 CPM 19,500 CPH

1% 195 CPH

19,305 CPH

124,494,196 CPY

$ 1,742,918

5-1 2

Table 5-9

COST SAVINGS COMPARISONS BETWEEN CONVENTIONAL UV AND

1.12 BILLION PRINTED CUP CAPACITY (81) ON-MANDREL UV PROCESSORS FOR A PLANT RATED AT

Printers Required

Annual Operating Costs per Printer

Annual Operating Cost

Anuual Saving using On-Mandrel Drying

Conventional UV On-Mandrel UV

12 9

$ 51,522

0 618,264

$ 47,244

$ 425,196

$ 193,068

5-1 3

Table 5-10

PRELIMINARY COST COMPARISON FOR THERMAL AND ELECTRON BEAM CURING OF ADHESIVES (127)

-

I. Thermal (60" oven capable of 100 ft/minute) __

Assume a consumption of 6 MBTU/hour in an oven costing $160,000. Area of the oven -120' x 12', -1500 ft2. Utilization of 85% with 8% downtime for maintenance (2,567 -yd2/hr),

Amortize capital c sts over 5 years

Fuel costs at 6 MBTU/hra $13.50/hr Maintenance parts .30/hr Services (cooling water, 20 kW auxi 1 i ary power, air, Etc . ) 2.OO/hr

Operator labor (100% OH) 10.00/hr Total operating costs $25.80/ hr

Electron Beam (60" curing head capable of 120'/minute)

Assume a consumption of 20 kilowatts in a $tation costing $200,000. Area of curing station -12' x 16', -200 ft . Utilization of 90% with under 5% downtime for maintenance (3,400 yd2/hr).

Amortize capital c sts over 5 years $40,000.OO/yr 200.OO/yr

Maintenance contract for system 5,000.OO/yr Power costs at 3 /kWhr $ .60/hr Inert gas costs 2.OO/hr Services (water, air, etc.) .20/hr Operator 1 abor (100% OH)C 5.OO/hr Total operating costs $ 7.80/hr

$32,000.OO/yr 1,500.OO/yr Space use at $l/ft B

11.

Space use at $l/ft B

The following gross hourly and square yard operating costsd result based upon these numbers:

2000 hr $fy& 4000 hr $/vdz 6000 hr $fy&

Thermal Oven $41.35 0.016 $32.95 0.013 $30.15 0.012 Electron Processor 30.40 0.009 19.10 0.006 15.35 0.004

aBased upon gas costs of $2.25/1000 cu. ft. for gas at 1000 BTU/cu. ft. bBased upon a full man for operation and maintenance. CBased upon 0 .5 man for operation. dBased upon the use of water based adhesive whose dry mil cost is equivalent to that of the electron curable system.

5-1 4

Table 5-11

ECONOMICS, PHOTOCHEMICAL vs. THERMAL PRODUCTION LINES PRESSURE-SENSITIVE ADHESIVE TAPE AND LABELS (1 27) -

Line speed ( f t / m i n)

Powep consumption (W

Operating costs ($1 Power Maintenance Nitrogen gas Water

Tota l Costs

Capi ta l Costs

NA = not appl icable

Electron Beam UV Cure (Sol vent-Based Adhesi v e l

300 300 300

40.2 510 5,100

.81 10.20 18.00 3.50 4.50 2.70 2.75 NA NA .20 NA NA

7.26 14.70 20.70

$200,000 $13,000 $130,000

5-1 5

c a t i o n s .

t h a t t h e process ing opera t i ons be c o s t - e f f e c t i v e under h i g h p r o d u c t i o n r a t e cond i -

t i o n s ; these c o n s t r a i n t s can o n l y be achieved th rough r a d i a t i o n p rocess ing

techn iques . (128)

The comp lex i t y and h igh performance q u a l i t y o f these p roduc ts demands

P l a s t i c and Rubber M a t e r i a l s

Several f a c t o r s i n d i c a t e t h a t e l e c t r o n beam (EB) systems a re more c o s t - e f f e c t i v e

than thermo-chemical systems f o r p rocess ing p l a s t i c and rubber m a t e r i a l s .

0 R a d i a t i o n process ing can save bo th energy and p r o d u c t i o n c o s t . The e l e c t r i c a l energy used t o generate e l e c t r o n beams i s more expensive than f o s s i l - f u e l energy cos ts assoc ia ted w i t h steam o r gas f i r e d ovens, b u t t h e lower energy i n p u t per u n i t o f m a t e r i a l processed by EB techniques more than o f f s e t s t h i s h i g h e r o p e r a t i o n a l cos t .

0 R a d i a t i o n process ing equipment saves f l o o r space compared t o heat c u r i n g systems r e q u i r i n g l o n g steam tubes o r expansive h o t a i r ovens. Typ ica l r a d i a t i o n process ing equipment r e q u i r e s l e s s than 1,000 square f e e t o f f l o o r space.

0 There i s l e s s produc t scrap l o s s w i t h r a d i a t i o n process ing techn iques due t o e f f i c i e n t th rough cure. Thermal cu re p ro - cesses can r e s u l t i n overcure and nonuni form cu re o f a p roduc t .

0 Thermo-chemical c u r i n g systems r e q u i r e t h e use o f pe rox ide and o t h e r c a t a l y s t s n o t r e q u i r e d i n r a d i a t i o n (h igh-energy) p ro - cess ing techno log ies . E l i m i n a t i o n o f these thermal cu re ca ta - l y s t s reduces t h e l e v e l o f a n t i o x i d a n t s and an t i ozonan ts by as much as 50%, thus e f f e c t i n g a cons ide rab le m a t e r i a l sav ings f o r t h e r a d i a t i o n cured produc t .

0 The c o s t o f e l e c t r o n beam r a d i a t i o n i n t h e pas t t h r e e decades has been reduced f rom $4.00 t o produce 1 KWH o f r a d i a t i o n t o app rox ima te l y $0.03 t o $0.25 per KWH, depending on t h e equ ip- ment c o n f i g u r a t i o n requ i rements . Th is r e d u c t i o n has come about p r i m a r i l y due t o t h e h ighe r e f f i c i e n c y o f success ive genera- t i o n s o f high-energy e l e c t r o n beam a c c e l e r a t o r equipment.

Comparative examples f o r con t inuous thermal v u l c a n i z a t i o n ( C V ) and h igh-energy

e l e c t r o n beam (EB) c u r i n g ( c r o s s - l i n k i n g ) of po l ye thy lene w i r e i n s u l a t i o n i s shown

i n Tables 5-12 and 5-13. As can be seen i n Table 5-12 t h e a c t u a l t o t a l energy cos ts [energy c o s t l y e a r (4,000 hours ) ] f o r EB a re h ighe r than t h e C V process b u t

t h e energy c o s t per pound of p roduc t manufactured i s $0.013 f o r CV and o n l y $0.006

f o r EB.

c o s t / l b o f i n s u l a t i o n (2,659,500 l b l y e a r ) i s $0.086; t h e c o s t / l b o f i n s u l a t i o n

(8,697,000 l b / y e a r ) f o r t h e EB process i s o n l y $0.046. (129,130)

S i m i l a r r e s u l t s a re descr ibed i n Table 5-13 i n which t h e C V process

5-16

Table 5-12

ENERGY COMPARISON, CV AND EB, FOR WIRE INSULATION CROSS-LINKING (129)

Systems P r o p e r t i e s cv a E B ~

Linespeed, fpm 38 233

I n s . l b / h r

BTU /1 b -

207.5 1260

5783 1127

Energy c o s t / l b $0.013 $0.006

Energy c o s t l y r (4000 h r ) $10,560 $29 500

1 b l y r 1000's a30 5,040

Gauge, AWG (250 MCM)

Conductor , m i 1 s ( 575 1

I n s u l a t i o n , m i l s (92)

OD over ins. , m i l s (759)

I n s . sp. g r a v i t y (1.0)

I n s . w t . l b 1 0 0 0 / f t (91)

EB kV (1564)

aAssume 750 e t c .

bia4 kw e t c .

5-1 7

Table 5-13

COST COMPARISON DATA (CV/EB) (129)

CV System

-

Electron Beam System

Caei tal Costs CaDi tal Costs

6" extruder 1 i ne and CV, installed, complete with steam generator $750,000

6" extruder 1 i ne w. 0. CV, installed complete $300.000

1500 kv 50 mA Dynamitron, complete with accessories 480,000

Wire Line, complete 90,000

Instal 1 ation, shielding etc. 125,000

Total : $995,000

OPeratinq Costs, Annual Oeeratinq Costs, Annual

Equipment (assuming 10 yr amortization $ 75,000

Labor (1 man/shift) 72 , 000 Steam 17,000 Power 45 , 000 Water 2,000 Maintenance 16,000 Taxes, insurance, etc. 1,500

Equipment (assuming 10 yr amortization) $ 99,500

Labor (2 men/shi ft) 144,000 Steam - - Power (2 extruders and accelerator) 131,100

Water 8,000 Maintenance 14,400 Taxes, insurance, etc. 2 , 000

Total : $228.500 Total : $399,000

$0.086 Cost/l b o f insul at i on $0.046 Cost/l b o f i nsul ati on 2,659,500 lb/yr 8,697,000 1 b/yr

5-18

Other economic s t u d i e s on EB p rocess ing of p o l y e t h y l e n e p ipe , ca lendered rubber

sheet , and p o l y e t h y l e n e f i l m can be found i n Reference 131.

PLASMA PROCESSING

Plasma c o a t i n g and polymer s u r f a c e t rea tmen t equipment and processes a re we1 1 -- e s t a b l i s h e d f o r t r e a t i n g batches o f smal l o b j e c t s and, i n some cases, cont inuous

p rocess ing has had commercial success i n t h e t e x t i l e and paper c o a t i n g i n d u s t r i e s .

An es t ima ted c o s t t o plasma t r e a t smal l o b j e c t s (ba tch p rocess ) and a cont inuous web o r f i l m ( p o l y v i n y l 3 i l W d e ) i s g i ven i n Tables 5-14 and 5-15. (126-,132) -These

t r e a t m e n t processes are unique t o plasma p rocess ing techno log ies ; t hus comparisons

w i t h o t h e r t rea tmen t processes are n o t p o s s i b l e .

IMPACT OF FUEL P R I C E S

Because energy c o s t s a re a l a r g e f a c t o r i n thermal p rocess ing o f po l ymer i c mate-

r i a l s , i t would no rma l l y be expected t h a t f u e l p r i c e s shou ld have a l a r g e e f f e c t

on t h e f u t u r e compe t i t i veness o f r a d i a t i o n process ing t e c h n o l o g i e s . The p r o j e c t i o n

o f f u t u r e energy p r i c e s i s approximate a t bes t , b u t t h e gross t r e n d i s f o r t h e c o s t

of e l e c t r i c i t y t o i nc rease a t a r a t e much l e s s than t h a t f o r n a t u r a l gas o r o i l .

The p r e s e n t Department o f Energy p r o j e c t i o n s show t h a t t h e c o s t o f e l e c t r i c i t y w i l l

i n c r e a s e r a t h e r s l o w l y through 1995, whereas t h e c o s t o f n a t u r a l gas i s expected t o

double d u r i n g t h i s t i m e p e r i o d . (133) Therefore, by 1995, r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s (energy e f f i c i e n c i e s o f app rox ima te l y 90 p e r c e n t ) w i l l remain

a t t r a c t i v e f r o m an o v e r a l l energy c o s t v iewpo in t . Energy sav ings alone, however,

has n o t been a major f a c t o r i n c o n v i n c i n g some i n d u s t r i e s t o s w i t c h from thermal

c u r i n g (energy i n t e n s i v e ) t o r a d i a t i o n p rocess ing t e c h n o l o g i e s f o r manufacture o f

t h e i r p roduc t m a t e r i a l s . O f course l a c k o f f u l l f u e l a v a i l a b i l i t y , such as was

exper ienced i n t h e 1 9 7 0 ' ~ ~ f o r c e d many i n d u s t r i e s , e s p e c i a l l y t h e p r i n t i n g indus- t r y , t o q u i c k l y e v a l u a t e r a d i a t i o n p rocess ing techniques. They soon d i scove red

many a d d i t i o n a l b e n e f i t s ( p r o d u c t i o n speed, p roduc t q u a l i t y , va lue added p roduc ts ,

e t c ) bes ides energy savings; t hese a d d i t i o n a l f a c t o r s became t h e d r i v i n g f o r c e f o r

i n c r e a s i n g t h e growth r a t e o f r a d i a t i o n p rocess ing of po l ymer i c m a t e r i a l s f o r a

wide v a r i e t y o f o t h e r i n d u s t r i a l a p p l i c a t i o n s . (126) -

5-1 9

Table 5-14

ESTIMATED COST TO PLASMA TREAT SMALL OBJECTS (132)

Bases and Assumptions: Annual capacity: 40 million pa r t s per year Operation schedule: 16 hours/day, 250 days/year January 1984 dol 1 ars

-CaDi t a l Investment:

Branson model 7150-12436 Pump Rotator f o r basket Spare baskets and handling equipment Ins t a l l a t ion of e l e c t r i c a l equipment Spare pa r t s Total

ODeratincl Costs

Cost El emen t

Raw materi a1 s E lec t r i c i ty Labor and supervision:

Operat or/f oreman Assis tant operator

Direct 1 abor :

Supervi s i on Maintenance:

Labor Materi a1 s

Payroll burden Overhead Factory suppl ies Qual i t y control

1 aboratory Insurance and property t a x Contingency Annual ized capi ta l

Total

recovery (10 years)

Operating Requi rement s

luni ts)

41,840 kwh

2.00 men 2.00 men

0.15 d i r e c t labor

0.02 cap invest 0.02 cap invest 0.25 1 abor/super 0.50 1 abor/super 0.06 d i r e c t 1 abor

0.10 d i r e c t labor 0.02 cap invest 0.04 d i r e c t cos ts

0.24 cap invest

Dol 1 a r s

65,000 15,000 10,000 10,000 5,000 3.000

108,000

Annual cos t ,

[dol 1 a r s )

0 2,929

50,000 40,000 13,500

2,160 2,160 26,415 52,830 5,400

9,000 2,160 8,262

25,823

240,639

Cost Per Thousand

Parts Jdol l a r s )

0 0.073

1.250 1.000 0.338

0.054 0.054 0.660 1.321 0.135

0.225 0.054 0.207

0.646

6.016

Note: a 1500 watt , 13.56 megahertz generator consumes 3 KW. A 194 cubic foot/min. pump i s driven by a motor of 10 horsepower (7.46 kilowatts) . = 4000 hrs/year x 10.46 KW = 41,840 KWH/year.

Total KW used

5- 20

Table 5-15

ESTIMATED COST TO PLASMA TREAT A CONTINUOUS WEB OF PVC FILM (26)

CaPi tal Investment:

Shinetsu apparatus (instal led) Installation o f electrical equipment Total

ODeratinq Costs:

Dol 1 ars

1,000,000 40,000

1,040,000

Cost Element

Raw materials Electricity Labor and supervision:

Operat or/f oreman Assistant operator

Direct 1 abor:

Supervision Maintenance:

Labor Materials

Payroll burden Overhead Factory supplies Qual i ty control

1 aboratory Insurance and property tax Contingency Annualized capital recovery

Total

Annual Costs Operating Annual

Requirements Cost, (units) (dollars)

0 1,280,000 kwh 89,600

2 men 50,000 2 men 40 , 000

0.15 direct labor 13,500

0.02 cap invest 20 , 800 0.02 cap invest 20,800 0.25 1 abor/super 31,075 0.50 1 abor/super 62,150 0.06 direct labor 5 , 400 0.10 direct 1 abor 9 , 000 0.02 cap invest 20 , 800 0.04 direct costs 14,525 0.24 cap invest 248.664

626,314

Cost Per Thousand Sq. Ft. (dol 1 ars)

0 0.311

0.174 0.139 0.047

0.072 0.072 0.108 0.216 0.019

0.031 0.072 0.050 0.863

2.175

Note: Total power demand = 320 KW for pumps, generator and ancillaries 16 hrs/day x 250 days/year = 1.28 million KWH.

5- 21

Sec t ion 6

SALES HISTORY/MARKET PROJECTIONS

The o v e r a l l growth o f r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s (UV and E6 r a d i a -

t i o n p rocess ing a p p l i c a t i o n s ) f o r t h e f u t u r e depends on t h e growth ( h i s t o r i c and

f u t u r e ) o f c e r t a i n i n d i v i d u a l i n d u s t r i e s and s p e c i f i c market segments w i t h i n these

i n d u s t r i e s which can use o r c o n v e r t t o r a d i a t i o n p rocess ing t e c h n o l o g i e s (Tab le

6-1) . (134) S p e c i f i c segments o f t h e c o a t i n g s i n d u s t r y se rve as examples i n t h i s

s e c t i o n . Market p r o j e c t i o n s f o r r a d i a t i o n p rocess ing equipment a r e prov ided, and

c o m p e t i t i v e f a c t o r s f rom t h e e x i s t i n g and emerging techno log ies a re summarized.

COATINGS

The c o a t i n g s i n d u s t r y has an o v e r a l l h i s t o r i c growth r a t e between 8 t o 10% p e r year

(1977 t o 1982) f o r t h r e e combined major p roduc t types:

t u r a l c o a t i n g s , i n d u s t r i a l p roduc t f i n i s h e s , and s p e c i a l purpose c o a t i n g s ( F i g u r e

6-1). The most i m p o r t a n t area f o r p e n e t r a t i o n by r a d i a t i o n p rocess ing techniques

i s t h e i n d u s t r i a l p r o d u c t f i n i s h i n g ( IPF) l i n e segment o f t h e c o a t i n g s i r l d u s t r y .

Table 6-2 l i s t s t h e t o t a l i n d u s t r i a l p roduc t f i n i s h i n g shipment va lues f o r 1977

through 1985 w i t h t h e p r o j e c t e d gross n a t i o n a l p roduc t ( G N P ) va lues f o r each

year . (135-139) The growth r a t e s f o r GNP a r e w e l l e s t a b l i s h e d (10 pe rcen t

a n n u a l l y ) and can be e a s i l y p r o j e c t e d i n t o t h e year 1990. (135) The average r a t i o

o f IPF t o GNP f o r t hese n i n e years i s app rox ima te l y 0.92; thus, a p r o j e c t e d IPF

d o l l a r v a l u e volume f o r 1990 i s c a l c u l a t e d t o be about 6 b i l l i o n d o l l a r s . (140) A

f u l l range o f p r o j e c t e d I P F growth r a t e s can a l s o be ob ta ined if one assumes t h a t

t h e IPF/GNP r a t i o v a r i e s between 0.5 and 1, r e s u l t i n g i n 1990 shipment va lues o f

between about 3 ( l o w v a l u e ) and 7 ( h i g h v a l u e ) b i l l i o n d o l l a r s .

t r a d e s a l e s o r a r c h i t e c -

I n 1976-1977 shipments o f r a d i a t i o n c u r a b l e c o a t i n g s (UV and EB) were $7 t o 12

m i l l i o n , app rox ima te l y 0.5% o f t h e t o t a l va lue o f i n d u s t r i a l p roduc t f i n i s h i n g

shipments f o r t h a t year . (124,141) c o a t i n g s i nc reased somewhere between 2.4% and 5% o f t h e t o t a l I P F shipments va lues

($55 t o 114 m i l l i o n ) and i n 1982 and 1985 r a d i a t i o n c u r a b l e c o a t i n g s rep resen ted

between 2.8% and 6% ($71 t o 153 m i l l i o n ) and 4.5% and 6% ($168 t o 222 m i l l i o n )

r e s p e c t i v e l y o f t h e t o t a l IPF shipments f o r these yea rs . I f one assumes t h a t i n

I n 1979 t h e shipment f o r r a d i a t i o n c u r a b l e

6-1

Table 6-1

RADIATION PROCESSING END USE MARKETS AND PRODUCTS (1 34) -

End Use Markets Products

Graphic Arts

Packaging

Consumer

Transportation

Construction

Electronics

Communi cation

Inks (UV, EB) Photopolymer plates (UV) Reproduction films (UV) Paper release coatings (EB)

Inks (UV, EB) Photopolymer plates (UV) Overprint coatings (UV, EB) Shrink films (EB) Barrier coatings (UV, EB) Labels (UV) Tapes (UV, EB)

Magazines (UV) Catalogues (UV) Book covers (UV) Credit cards (UV) Decorative mirrors (UV) Plaques (UV) Flooring (UV)

Nameplates (UV, EB) Assembly parts (EB, UV) Replacement parts (UV, EB) Decorative finishes (UV, EB)

Panels (wood & particle

Flooring (UV) Wallpaper (UV)

board) (UV, EB)

Printed circuit inks (UV) - marking (UV) - etching (UV) - solder masks (UV) Photopolymer plates (UV) Photopolymer masks (UV)

Speakers (UV) Fiber optics (UV) Magnetic tapes (EB)

Decals (UV) Transfer letters Coated foils (UV, EB) Coated films (UV, EB)

Album jackets (UV, EB) Cosmetic cartons (UV) Liquor cartons (UV) Closures (UV) Bottles & bottle caps (UV) cups (UV) Cans (UV)

Furniture (UV) Appliances (UV, EB) Lami nates (EB) Name plates (UV) Flocked fabric (EB) Footwear (EB) Permanent press (EB)

Laminations (EB) Conductive coatings (UV) Electrical insulation (EB)

Binders for abrasives (EB) Laminations (EB) Electrical insulation (EB) Coil coated stock (EB)

Electrical i nsul at ion (EB) Photo resists (UV) Wire coatings (UV, EB) Conductive coatings (UV, EB) Encapsulation/conformal coatings (UV, EB)

Dielectric coatings (EB) Electrical insulation (EB) Wire & coil bonding (EB)

Product usually prepared by ultraviolet (UV) or electron beam (EB) radiation processing conditions .

6-2

- Q 0 I- c

I I I I I I I I I I I 0

O O O r F 0 Q) O C D IC O % d m (v

0 0 0 0

0 0 0 0 O O O 0 0

0 0 0 0 F F

6-3

1990 r a d i a t i o n c u r a b l e c o a t i n g s w i l l be between 6 and 10% of t h e t o t a l IPF $ m i l - l i o n shipment values f o r t h a t year , then t h i s would equate t o a v a l u e f o r t o t a l

r a d i a t i o n c u r a b l e c o a t i n g shipments o f between $374 and $624 m i l l i o n as c a l c u l a t e d

f r o m t h e r e l a t i o n s h i p : (0.06 t o 0.10) ( I P F m i l l i o n $ = 0.92 GNP b i l l i o n $1. A

f u l l range o f p r o j e c t e d va lues can a l s o be ob ta ined u s i n g t h e r e l a t i o n s h i p (0.06 t o

0.10) ( IPF m i l l i o n $ = 0.5 t o 1 GNP b i l l i o n $ 1 (Table 6-2).

R a d i a t i o n c u r a b l e c o a t i n g shipments can be f u r t h e r separated i n t o two major areas:

UV and EB cured c o a t i n g systems. I n 1976-197_7_the d i v i s i o n f o r t o t a l r a d i a t i o n

c u r a b l e c o a t i n g shipments was 0.4 pe rcen t f o r UV and 0.1 pe rcen t f o r EB t e c h n o l -

og ies. I n 1979, 1982, and 1985 t h i s d i v i s i o n became 2.1, 2.2, 3.3 pe rcen t f o r UV and 0.3, 0.6, 1.2 pe rcen t f o r EB r e s p e c t i v e l y .

i s expected t o be g r e a t e r than t h e use o f UV c o a t i n g s because o f t h e advantage o f u s i n g EB over UV p rocess ing techniques f o r h i g h speed-high volume c o a t i n g

a p p l i c a t i o n s .

I n t h e year 1990 use o f EB c o a t i n g s

I n d u s t r i a l p roduc t f i n i s h e s can a l s o be d i v i d e d i n t o n i n e market segments:

wood, t r a n s p o r t a t i o n , machinery, appl iance, packaging, p l a s t i c p a r t s , e l e c t r o n i c s

and miscel laneous ( F i g u r e 6-2).

UV/EB r a d i a t i o n p rocess ing techniques a re t h e wood, meta l , packaging, and p l a s t i c

f i n i s h i n g i n d u s t r i e s . (47 ) -

metal ,

The areas most l i k e l y t o i n c r e a s e t h e i r use o f

Wood F i n i s h i n g

I n t h e wood f i n i s h i n g i n d u s t r y ( f l a t s t o c k ) t h e consumption o f UV r a d i a t i o n c u r a b l e

c o a t i n g systems f o r 1974-75 was 6,803 m e t r i c t ons o r 15 m i l l i o n pounds o f mate-

r i a l .

a d e n s i t y o f 8 pounds/gal lon f o r c l e a r f i n i s h e s (10% o f t h e market o r 1.5

m i l l i o n l b s "= 200,000 g a l l o n s ) and a d e n s i t y o f 15 pounds/gal lon f o r f i l l e r coa t -

i n g s (90% of t h e market o r 13.5 m i l l i o n pounds "= 900,000 g a l l o n s ) . (124) I n 1981

t h e consumption of UV cu red c o a t i n g s f o r t h i s i n d u s t r y was 10 m i l l i o n pounds o r

0.73 m i l l i o n g a l l o n s . (142) - g a l l o n s sh ipped f o r t h i s i n d u s t r y ( F i g u r e 6-31 i n d i c a t e s t h a t t h i s market w i l l have

T h i s conver t s t o app rox ima te l y 1.1 m i l l i o n g a l l o n s o f c o a t i n g , assuming

The r e c e n t annual decrease i n volume o f m i l l i o n s o f

a r e l a t i v e l y low 1990 f i n a l shipment va lue. (47 L 135)

t i o n c u r a b l e c o a t i n g s a re o n l y 5 t o 9% o f t h e p r e f i n i s h e d board shipment va lue

(1 t o 2% o f t h e t o t a l wood f i n i s h i n g marke t ) and i n t h i s a p p l i c a t i o n , I R c o a t i n g s

r e p r e s e n t a major t h r e a t t o U V - r a d i a t i o n p rocess ing systems.

c o a t i n g s a r e n o t cons ide red t o be a major p roduc t f o r t h i s market because t h e r e -

q u i r e d c o a t i n g s a r e t h i n enough o r t h e pigment t y p e and l e v e l s a r e such t h a t UV

and I R p rocess ing techniques can c u r e t h e f i n i s h f o r acceptable p roduc t performance

A t t h e p resen t t i m e UV r a d i a -

E l e c t r o n beam (EB)

6-4

Table 6-2

1977

1978

1979

1980

1981

1982

1983

1984

1985

1990

ANNUAL SHIPMENT VALUES FOR THE INDUSTRIAL PRODUCT FINISHING (IPF) MARKET; GROSS NATIONAL PRODUCT

(GNP) VALUES AND IPF/GNP RATIOS (135-139)

I n d u s t r i a1 Product Gross Na t iona l F in i shes (IPF) Product (GNP)

( m i l $1 ( b i l $1

1961

2092

2284

2418

2737

2546

2907

3428

3705

1918

2156

2414

2626

2926

3085

3400

3790

4265

6785

I P F(GN P

1.02

0.97

0.95

0.92

0.93

0.83

0.86

0.90

0.87

IPF m i l $ 0.92 h i s t o r i c a l average (GNP b i l $)

IPF m i l $ 0.5 (6785) = 3121 (1990 low value)

I P F f mil $ 2 1 (6785) = 6785 (1990 high value)

6-5

AVG IPF MARKETS

A = Metal Coatings 6 = Coil Coatings C = Wood Coatings D = Transportation E = Machinery F = Appliance G = Packaging H = Plastlcs I = Electronics

J = Miscellaneous

15.5% 9.5%

21 .O%

8.0% 3.5%

10.5% 7.0% 3.5% 3.0%

18.5%

Figure 6-2. Major Market Segments f o r I n d u s t r i a l Product Finishes (47)

6- 6

F

ia a

6-7

l e v e l s . The f u t u r e f o r UV r a d i a t i o n process ing i s i n t h e area o f three-d imensional

f i n i s h i n g opera t i ons which o f f e r a v e r y a t t r a c t i v e growth o p p o r t u n i t y f o r t h e tech -

no logy . p r e f i n i s h e d board market w i l l remain c o n s t a n t (1 m i l l i o n g a l l o n s ) th rough 1990,

t h e n t h i s would equate t o a shipment va lue o f $24 m i l l i o n f o r t h a t year . I f UV r a d i a t i o n process ing pene t ra tes t h e t h r e e d imensional f i n i s h i n g market area and

inc reases t h e volume of c o a t i n g s shipped t o 2 m i l l i o n g a l l o n s i n 1990 then t h i s

would equate t o a shipment va lue o f app rox ima te l y $48 m i l l i o n f o r t h e yea r 1990.

These p r o j e c t i o n s are made an. t h e assumptions t h a t t h o o v e r a l l wood f i n i s h i n g i n -

d u s t r y market growth w i l l remain cons tan t (39 m i l l i o n g a l l o n s =- $234 m i l l i o n v a l u e )

o r have a c o a t i n g shipment va lue i n 1990 v e r y s i m i l a r t o t h a t observed i n 1985

(Tab le 6-31,

If one assumes t h a t t h e p e n e t r a t i o n o f UV r a d i a t i o n p rocess ing i n t o t h e

Meta l D e c o r a t i v e Coat ings

The t o t a l meta l f i n i s h i n g market segment f o r IPF has i nc reased ( 5 % o v e r a l l average

annual i n c r e a s e ) f rom 80 m i l l i o n g a l l o n s o f c o a t i n g s sh ipped i n 1980 t o 98 m i l l i o n

o f g a l l o n s sh ipped i n 1985.

separa te p roduc t l i n e s ( can -con ta ine r c o a t i n g s , c o i l c o a t i n g s , f u r n i t u r e - f i x t u r e s ,

and genera l me ta l s ) ; t h e can-conta iner and genera l meta ls c o a t i n g s a r e o f most

i n t e r e s t t o c u r r e n t r a d i a t i o n p rocess ing t e c h n o l o g i e s ( F i g u r e 6-4) . (47 135)

Th is market segment can a l s o be s u b d i v i d e d i n t o f o u r

A

R a d i a t i o n c u r a b l e shipments were 8 m i l l i o n pounds (1 m i l l i o n g a l l o n s ) i n 1974 and

10 m i l l i o n pounds (1.25 m i l l i o n g a l l o n s ) i n 1981. These shipment va lues rep resen t app rox ima te l y 2 t o 3% of t h e combined c o n t a i n e r c o a t i n g s and genera l me ta l markets

b u t a re o n l y 1 t o 2% of t h e t o t a l meta l f i n i s h i n g market segment. (124,142)

The h i s t o r i c and p r o j e c t e d growth r a t e f o r t h i s market segment i s shown i n Table

6-4. The combined c o n t a i n e r and genera l me ta l market areas a re p r o j e c t e d t o i n -

crease f r o m 51 m i l l i o n g a l l o n s (1985) t o 80 m i l l i o n g a l l o n s (19901, which equates

t o app rox ima te l y $584 m i l l i o n combined c o a t i n g shipments f o r t h a t yea r . I f one

assumes t h a t i n 1990 r a d i a t i o n c u r a b l e c o a t i n g shipment w i l l be between 1 and 4 m i l l i o n g a l l o n s (1 t o 5% of t h e combined c o n t a i n e r - genera l meta l volume s h i p -

ments) t hen t h i s would equate t o between $24 and 96 m i l l i o n ( 4 t o 16% o f t h e com- b i n e d c o n t a i n e r and genera l meta l markets, and 2 t o 8% o f t h e t o t a l meta l f i n i s h i n g

market segment d o l l a r v a l u e s ) f o r t h a t yea r . (140-142)

6-8

Table 6-3

ANALYSIS OF CONVENTIONAL AND RADIATION CURABLE COATINGS FOR WOOD FINISHING MARKET AREAS (47,135,140,141)

IPF Market Seqment

Shipment , Million Million

Years o f Gal 1 ons of Pounds Million

o f $3

Wood Finishes

Total

Furniture and Fixtures

Pref i n i shed

UV-Radiation Curable

Wood Finishes Total

UV-Radi ati on Curable

Historical

1980- 1985 73-39

1980-1985 53-27

1980- 1985 20-12

1975- 19$1 1-0.7 15-10

Future

1990 39

1990 1 - 2 15-30

438-234

318-162

120-72

24-17

234

24-48

a$6/gallon conventional coatings, 12-35 $/gallon radiation curable coatings.

6-9

3 = s i .2 0

i i h C O

- 0 1 O m - w P -2 sg 0 I-

6-1 0

Table 6-4

ANALYSIS OF CONVENTIONAL AND RADIATION CURABLE COATINGS FOR METAL FINISHING MARKET AREAS (47.140.141)

I P F Market Sesment

Metal Finishes

Tot a1

Can-container

Coi 1 coatings

Furniture fixtures

General metals

Radi at i on curabl e coatings

Metal Finishes Total

Can-container

Coi 1 coatings

Furniture fixtures

General metals

Radiation curable coatings

Shipment, Mill ion

Years of Gal 1 ons

1980- 1985

1980- 1985

1980- 1985

1980-1985

1980- 1985

1979-1981

1990

1990

1990

1990

1990

1990

Historical

80 - 98

35-41

25-37

10-10

10-10

1-1.25

Future

160

60

60

20

20

1-4

Mill ion Mil 1 ion of Pounds o f 79-80s

569-700

249-292

183 - 27 1

70-70

67-67

8- 10 24-30

1174

450

450

140

134

8-32 30-96

6-1 1

Pack ag i ng C o a t i ngs

The packaging i n d u s t r y (paper, f o i l , p l a s t i c f i l m ) has shown an i n c r e a s e i n c o a t i n g

shipments f rom 20 m i l l i o n g a l l o n s ($130 m i l l i o n v a l u e ) i n 1980 t o 35 m i l l i o n g a l -

l o n s i n 1985. A l i n e a r e x t r a p o l a t i o n f rom 1980 t o 1990 f o r t h i s i n d u s t r y p r o j e c t s

t h a t t h e volume of c o a t i n g s shipped i n 1990 c o u l d reach 55 m i l l i o n g a l l o n s va lued a t $403 m i l l i o n ( F i g u r e 6-5) . R a d i a t i o n c u r a b l e c o a t i n g s used i n t h i s i n d u s t r y i n

1979-1981 were va lued a t between $6 and $22 m i l l i o n and a re expected t o i n c r e a s e up

t o a maximum of $118 m i l l i o n (between 5 and 29 percen t o f t h e t o t a l packaging s h i p -

ment v a l u e ) in.1990 (Tab le 6 4 ) . (47-,14@,141J-

-

~

-

Table 6-5

ANALYSIS OF CONVENTIONAL AND RADIATION CURABLE COATINGS FOR PACKAGING MARKET AREAS (47,141 1

Shipment , M i 11 i o n M i 11 i o n M i l 1 i o n

I P F Market Segment Years of Ga l l ons o f Pounds o f 79-80$

H i s t o r i c a l

Packaging (paper, f o i l , p l a s t i c f i l m ) 1980-1985 20-35

R ad i a t i on c u r a b l e c o a t i n g s 1974-1980

F u t u r e

2-8

130-257

6- 22

1990 35-55 257-403 Pack ag i ng

R a d i a t i o n c u r a b l e c o a t i n g s 1990 8-43 22-118

Other Coa t ing Systems

I n 1976 o n l y f o u r commerc ia l ly o p e r a t i v e f l o o r i n g l i n e s i n t h e U.S. used UV c u r i n g

technology, b u t b y 1985 a l l o f t h e major f l o o r i n g manufactures had exp lo red some

aspect o f t h e commercial u t i l i z a t i o n o f t h i s technology.

c u r a b l e c o a t i n g s i n 1979 was about 10 m i l l i o n pounds ($32 m i l l i o n ) ; i n 1985 t h i s

grew t o app rox ima te l y 16 m i l l i o n pounds ($50 m i l l i o n ) . Th i s consumption o f UV

c u r a b l e c o a t i n g s rep resen ts app rox ima te l y 10 t o 16% o f t h e t o t a l c o a t i n g products

used i n t h e manufacture o f v i n y l f l o o r i n g p roduc ts . A l l o t h e r segments o f t h e I P F

The consumption o f UV

6-1 2

market ( c o a t i n g s f o r f l e x i b l e p l a s t i c s , e lastomers, i n c l u d i n g f l o o r coa t ings , and o t h e r marke ts ) accounted f o r between $69 and $100 m i l l i o n shipment va lues o f r a d i a -

t i o n c u r a b l e c o a t i n g s f o r t h e years 1979-1982 and a re expected t o i n c r e a s e f rom

approx ima te l y $100 t o $140 m i l l i o n i n 1990. (47,124,134,135,141,142)

PRINTING

The h i s t o r i c growth of t h e p r i n t i n g i n k i n d u s t r y i s shown i n F i g u r e 6-6 and t h e

breakdown o f 1982 d o l l a r va lue shipments among t h e f i v e ma jo r p r i n t i n g processes i s shown -in Figure 6-7. (135,140,143) The t o t a r - m t n i o n d o l l a r shipment va lue f o r

t h i s i n d u s t r y can be p r o j e c t e d t o t h e year 1990 b y t h e f o l l o w i n g r e l a t i o n s h i p de- r i v e d f rom t h e i n f o r m a t i o n con ta ined i n Table 6-6 and F i g u r e 6-6.

P r i n t i n g I n k ( P I ) ( $ m i l l i o n shipments) "= 0.41 (GNP $ b i l l i o n )

Thus i n t h e year 1990 t h e expected t o t a l shipment va lue f o r t h i s i n d u s t r y shou ld be

approx ima te l y $2,782 m i l l i o n .

R a d i a t i o n c u r a b l e i n k s and o v e r p r i n t varn ishes a re m a i n l y used i n t h e packaging

and p r i n t i n g t r a d e consumption market areas. Packaging i n k s o f a l l t ypes make up

about 40% o f a l l i n k s consumed i n t h e U.S.

a r e t h e f o l l o w i n g :

The t h r e e ma jo r packaging submarkets

0 metal and p l a s t i c c o n t a i n e r s 0 f o l d i n g paper c a r t o n s 0 1 abel s .

P u b l i c a t i o n i n k s a r e used t o p r i n t newspapers, magazines, and books, and consume

approx ima te l y 20% o f t h e nonpackaging i n k markets; 40% of t h e nonpackaging i n k s a re

used i n t h e commercial f i e l d f o r p r i n t i n g commercial f l y e r s , d i r e c t m a i l , ads,

bus iness forms, e t c . Between t h e years o f 1975 and 1981 r a d i a t i o n c u r a b l e i n k s

i nc reased f rom 1.75 m i l l i o n pounds sh ipped t o 18 m i l l i o n pounds sh ipped w i t h a

shipment v a l u e i n c r e a s e o f between $5.33 and $54 m i l l i o n o r between 0.8 t o 4% o f

t h e t o t a l P I shipment v a l u e f o r those yea rs . If one assumes t h a t t h e use o f r a d i a -

t i o n c u r a b l e i n k s w i l l v a r y f r o m 4 t o 10% i n 1990 then t h e p r o j e c t e d shipment va lue

f o r t h i s yea r would be between $111 t o $278 m i l l i o n (app rox ima te l y 70% o f these

va lues r e l a t e t o packaging i n k market areas; 30% o f t hese va lues r e l a t e t o o t h e r

nonpackaging p r i n t i n g market segments) (Tab le 6-7). (47,141,142)

6-1 4

offset / 39%

// I \

Other

Screen 4 %

I Letterpress

9%

Flexographic 18%

Total 1982 U.S. Shipments = $1.36 to 1.48 Billion

Figure 6-7. Processes (E)

Market Share o f Major Printing

6-1 6

Table 6-6

ANNUAL NATIONAL

SHIPMENT VALUES FOR PRINTING INKS; GROSS PRODUCT VALUES AND P I / G N P RATIOS (135,140)

P r i n t i n g I n k s Gross N a t i o n a l Product Year ( P I ) ( m i l $ ) (GNP) ( b i l $1

1977

1978

1779

1980

1981

1982

1983

1984

1985

905

1000

1110

1250

1380

1495

1540

1595

1918

2156

2414

2626

2926

3085

3400

3790

1990 6785

P I ( m i l $1 9 0.41 h i s t o r i c a l average (GNP b i l $1.

P I / G N P

0.47

0.46

0.46

0.48

0.47

0.48

0.45

0.42

6-1 7

Table 6-7

CONVENTIONAL AND RADIATION CURABLE PRINTING INK INDUSTRY MARKET ANALYSIS (47,124,141,142)

-- Year

Mil $ Shipped (Percentage o f total

Mil Pounds PI shiPment values)

Printing ink (PI) industry total 1984

Radi at i on curable inks 1975

Printing ink industry total

Radiation curable inks

1977

1979

1981

1990

1990

Hi stori cal

1595

1.75

6

18

Future

5.33 (0.8 percent)

15 (1.7 percent)

20 (1.8 to 2 percent)

54 (4 percent)

2782

111 to 278 (4 to 10 percent)

6-1 8

I n a r e l a t e d area, p r i n t i n g p l a t e s can be manufactured v i a photopolymer t e c h n o l - og ies and i n 1969-1975 t h e t o t a l market f o r a l l types o f s e n s i t i z e d p r i n t i n g

p l a t e s , i n c l u d i n g UV-cured p r i n t i n g p l a t e s , was between $675 m i l l i o n and $1 b i l -

l i o n . R a d i a t i o n ( U V ) c u r a b l e m a t e r i a l s accounted f o r app rox ima te l y 8 t o 17% o f

t h i s market i n 1975-1979 (8 m i l l i o n pounds va lued a t $120 m i l l i o n ) and i n 1985 was

approx ima te l y 14 m i l l i o n pounds o r $210 m i l l i o n i n va lue. Th is market i s expected t o grow between $210 and $250 m i l l i o n i n va lue f o r t h e yea r 1990. (124,141)

ADH ES I VES -

The adhesive i n d u s t r y ( F i g u r e 6-8), s p e c i f i c a l l y t h e s y n t h e t i c and rubber adhesive

p roduc t l i n e s , can be p r o j e c t e d t o grow f rom $1880 m i l l i o n shipment va lues i n 1982

up t o $4139 m i l l i o n i n 1990 acco rd ing t o t h e r e l a t i o n s h i p s y n t h e t i c and rubber

adhesives ( A D ) ( m i l l i o n d o l l a r shipment v a l u e ) = 0.61 (GNP b i l l i o n d o l l a r )

desc r ibed i n Table 6-8. (135,140,144) R a d i a t i o n c u r a b l e t o t a l adhesives (UV and

E B ) shipment va lues i n 1983/84 were 5 m i l l i o n d o l l a r s f o r UV and $1.8 t o $2.2 m i l - l i o n f o r EB. These va lues are p r o j e c t e d t o grow up t o $11 m i l l i o n ( U V ) and $8

m i l l i o n (EB) f o r t h e year 1990 (Tab le 6-9) . UV c u r a b l e adhesives, such as s t r u c -

t u r a l adhesives (nonpressure s e n s i t i v e ) f o r t h e e l e c t r o n i c s , automot ive, and medi-

c a l dev i ce i n d u s t r i e s , are e l i m i n a t i n g o f f - l i n e c u r i n g o p e r a t i o n s b y i n c o r p o r a t i n g

c u r i n g i n t o a f u l l y automated assembly o p e r a t i o n .

new UV-curable adhesive systems and assoc ia ted a p p l i c a t i o n equipment ( c o s t

$50-500,000) f o r these market areas.

been d o u b l i n g y e a r l y s i n c e 1979.

f r o m $4 t o $10/ lb . I n 1983 t h e market f o r UV-cured s t r u c t u r a l adhesives a lone was

about $1 m i l l i o n and i s expected t o grow t o 1.25 m i l l i o n d o l l a r s i n 1990. (144-146)

I n 1983/84 L o c t i t e i n t r o d u c e d 11

The demand f o r L o c t i t e ' s cured adhesives has

The c o s t o f t hese s t r u c t u r a l adhesives ranges

Pressure s e n s i t i v e adhesives ( P S A ) are a l s o a l a r g e p o t e n t i a l s p e c i a l t y market f o r

r a d i a t i o n cured polymers. This market i s i n c r e a s i n g a t about t h e r a t e o f 10 t o 11% per yea r ( F i g u r e 6-9). (147)

PLASTICS AND RUBBER MATERIALS

T o t a l p l a s t i c s p r o d u c t i o n i n t h e U.S. has grown f rom approx ima te l y 38 b i l l i o n

pounds i n 1981 t o almost 50 b i l l i o n pounds i n 1985. The two most i m p o r t a n t polymer

m a t e r i a l s o f i n t e r e s t f o r r a d i a t i o n p rocess ing m o d i f i c a t i o n s a r e p o l y e t h y l e n e ( l ow-

d e n s i t y ) and p o l y v i n y l c h l o r i d e , which have a l s o i nc reased t h e i r combined t o t a l

p r o d u c t i o n r a t e s f r o m 14 b i l l i o n pounds i n 1981 t o 16 b i l l i o n pounds i n 1985

( F i g u r e 6-10). The market d i v i s i o n s f o r these two m a t e r i a l s i s shown i n F i g u r e 6-11. (135,148)

6-1 9

Table 6-8

HISTORICAL GROWTH OF SYNTHETIC AND RUBBER ADHESIVES (AD); GNP VALUES AND AD/GNP RATIOS (135,140)

1977

1979 - . . . - . . . 1978

1980 1981 1982

1990

S y n t h e t i c and Rubber Adhesives, (AD) M i l $ s h i m e d

1222 1367 1506 1545 1667 1 aao

GNP B i l $

1918 0.64 2156 0.63 2414 0.62 2626 0.59 2926 0.57 3085 0.61

AD/GNP

6785

S y n t h e t i c and r u b b e r adhesives (AD) ( m i l $ shipment v a l u e ) = 0.61 h i s t o r i c average v a l u e (GNP b i l l $ ) .

Tab le 6-9

CONVENTIONAL AND RADIATION CURABLE SYNTHETIC AND RUBBER ADHESIVE MARKET ANALYSIS (47,141)

H i s t o r i c

S y n t h e t i c and r u b b e r adhesives

R a d i a t i o n c u r a b l e adhesives

uv EB

F u t u r e

S y n t h e t i c and r u b b e r adhesives

R a d i a t i o n c u r a b l e adhesives

uv EB

Pounds Year Consumed

1982

1983184 76,00o-a5,000 1983184 0.5 m i l l i o n

1990

1990 290,000 1990 1.3 m i l l i o n

M i l l i o n s o f $ s h i m e d

1880

5 1.8 t o 2.2

4139

11 a

6-21

350

300

250

200

150

,-- Total PSA Market

1975 1980 1985

Figure 6-9. Shipments of Pressure Sens i t i ve Adhesives (147)

6-22

Total Plastics Production

45

40

u) 35

2 30

E 25

20

0 C 3

r 0

.- I -

15

10

5

t

t Low Density Polyethylene

1981 1982 1983 1984 1985

F i g u r e 6-10. (PVC) Annual P l a s t i c s P roduc t i on Capac i ty

Share o f Low Dens i t y Po lye thy lene (LDPE) and P o l y v i n y l C h l o r i d e (135)

6-23

100

Film and Sheet

L

53% All

Others Extrusion Coatings

_ . I Injection Molding

Wire and Cable

Extruded Items

I 67%

Calendered Sheet

All Others

Molded r Items

Coatings

Figure 6-11. 1985 Market Share f o r Low Density Polyethylene (LDPE) and Polyvinyl Chloride (PVC) (148)

; I I l~ I

It i s d i f f i c u l t t o p r o j e c t t h e a c t u a l growth o f h i g h energy r a d i a t i o n m o d i f i e d rubber and p l a s t i c m a t e r i a l s a t t h i s t ime, b u t a genera l overv iew o f t hese indus-

t r i e s can be desc r ibed i n a s e m i q u a n t i t a t i v e manner. To date, p l a s t i c s consumption

i n t h e U n i t e d S ta tes as a whole has grown h i s t o r i c a l l y a t r a t e s i n excess o f GNP.

Rubber consumption, however, has n o t ma in ta ined t h i s t r e n d (Table 6-10). (135,149)

Dur ing t h e 1970 's rubber consumption grew a t r a t e s o f app rox ima te l y 0.5-0.7 t h a t o f

GNP. has become nega t i ve .

These t r e n d s i n d i c a t e t h a t t h e o p p o r t u n i t i e s f o r r a d i a t i o n p rocess ing t e c h n o l o g i e s

a r e expected t o be g r e a t e r i n t h e p l a s t i c s i n d u s t r y than i n t h e rubber i n d u s t r y

marketp lace. I t shou ld be noted, however, t h a t two companies (Raychem C o r p o r a t i o n

and t h e Cryovac D i v i s i o n o f W. R. Grace) have combined s a l e s o f a t l e a s t $400

m i l l i o n per year manu fac tu r ing p o l y o l e f i n h e a t - s h r i n k a b l e s leeves, t u b i n g , boots ,

wrap and r a d i a t i o n c r o s s - l i n k e d p o l y e t h y l e n e heat s h r i n k a b l e f o o d wrap

p roduc ts . (150)

I n t h e 1980 's t h i s r a t i o has d e c l i n e d even f u r t h e r and

~~

ELECTRONICS AND COMMUNICATIONS

The growth o f t h e e l e c t r o n i c s i n d u s t r y i s bes t rep resen ted by t h e growth o f spe-

c i f i c i n d i v i d u a l components , such as i n t e g r a t e d c i r c u i t s ( I C ) ( F i g u r e 6-1 2 ) . The

1984 d o l l a r e s t i m a t e o f e l e c t r o n i c chemicals usage (dev i ces and encapsu lan ts ) i n

t h e U.S. i s shown i n F i g u r e s 6-13, 6-14, and 6-15. (151,152)

The e l e c t r o n i c s and m i c r o e l e c t r o n i c s i n d u s t r i e s use coa t ings , adhesives, and i n k s

f o r a wide range o f a p p l i c a t i o n s b u t p r i m a r i l y f o r p r i n t e d c i r c u i t boards (PCB) .

Some of t h e c a t e g o r i e s o f systems used i n these i n d u s t r i e s a re as f o l l o w s :

0 UV c u r a b l e screen i n k s e L i q u i d p h o t o r e s i s t s f o r PCB and i n t e g r a t e d c i r c u i t s 0 L i q u i d s o l d e r marks (UV c u r a b l e ) 0 L e t t e r i n g and nomenclature i n k s 0 Conformal c o a t i n g s 0 Dry f i l m r e s i s t s and s o l d e r marks.

I n 1975-76 t h e p h o t o r e s i s t p r i n t e d c i r c u i t board markets used approx ima te l y $41

m i l l i o n wor th o f i n k s , i n c l u d i n g UV c u r a b l e m a t e r i a l s . Assuming t h a t 10% o f t h e

market was cap tu red b y UV-cur ing i n k s , t hen t h i s equates t o t h e market va lue f o r

UV-cur ing i n k s i n these a p p l i c a t i o n s o f about $4 m i l l i o n i n t h e U n i t e d

S ta tes . (124) I n 1979-81-85 t h e volume o f UV c o a t i n g s and i n k s was 8, 12 and 14

m i l l i o n pounds, r e s p e c t i v e l y , r e p r e s e n t i n g a market va lue o f between $93 m i l l i o n

and $160 m i l l i o n f o r t h i s segment o f t h e i n d u s t r y .

h i g h techno logy areas such as demonstrated b y t h e computer and communication

i n d u s t r i e s , t h e use o f r a d i a t i o n c u r a b l e m a t e r i a l s i n t h e year 1990 i s expected t o

Because o f t h e r a p i d growth f o r

6-25

Table 6-

U.S. Synthetic and Natural Rubber Consumption (135) -

m I N m

Year

1984 1983

-

1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969

Syn the t i c Rubber Consumption ( m i l l i o n s m e t r i c t ons ) Natura l Rubber

SBR SBR Poly- ConsumDtion To ta l

2.00 1.84 1.73 2.10 2.01 2.49 2.59 2.51 2.26 1.99 2.20 2.41 2.31 2.17 1.99 2.09

- (ex .- i atex )

.80

.88 1.02 1.03 1.32 1.42 1.45 1.30 1.19 1.28 1.48 1.47 1.39 1.24 1.34

Percent t o To ta l 1983 44 1970 63

I 1 i I ” -L . I

La tex -

.09

.08

.13

.ll

.15

.16

.14

.16 -09 .12 .13 .13 .12 .12 .14

5 6

B u t y l

.28

.22

.27

.24

.23

.23

.13

.12

.10

.12

.13

.12

.ll

.09

.10

15 5

Neoprene

.12

.12

. i4

.15

.18

.16

.17

.17

.14

.16 -15 .15 .15 .15 .13

6 6

N i t r i l e

.05

.07

.07

.06

.06

.06

.07

.06

.06

.07

.08

.06

.06

.06

.07

3 4

bu t ad; ene

.36

.27

.35

.31

.41

.41

.41

.34

.32

.35

.35

.31

.29

.28

.27

19 14

EPR (10’ M e t r i c Tons) - .75

.14 .68

.09 .66

.15 .63

.11 .59

.14 .74

.15 .69

.14 .71

.ll .66

.09 .61

.10 .65

.09 .62

.07 .58

.05 .52

.05 .51

.04 .54

8 2

Syn the t i c Rubber as % o f

To ta l T o t a l

2.75 2.54 74 2.43 75 2.52 76 2.44 77 3.08 77 2.90 76 3.06 77 2.63 76 2.45 75 2.79 75 2.80 77 2.66 78

78 2.25 77 2.38 77

104

103

u)

g 102 r 0 u) C 0 .- - - .- a

10’

1 0 0

1970 1975 1980 1985 1990 1995 Year

Figure 6-12. IC Shipments (151)

6-27

1984 Estimate $3 Billion

Figure 6-13. U.S . Electronic Chemicals

6-28

3

6-29

be 28 m i l

I n genera

es t ima ted

1990. I n

m a t e r i a l s e s t i m a t e d

i o n pounds va lued a t $320 m i l l i o n . (47,134,141)

, t h e t o t a l use o f e l e c t r o n i c chemicals f o r U.S. i n d u s t r i e s i n 1984 i s

t o be $3 b i l l i o n ( F i g u r e 6-13) and c o u l d reach $15 b i l l i o n i n t h e yea r

a r e l a t e d electronics/communication area t h e use o f r a d i a t i o n c u r a b l e

f o r magnet ic r e c o r d i n g media was $7 m i l l i o n i n 1983 ( T a b l e 6-11) and i s

t o grow t o $10 m i l l i o n i n 1990. (105)

Audio Media

Table 6-11

MAGNETIC M E D I A MARKET (105)

1983 F a c t o r y s a1 es-

( M i l l i o n $ 1

2,050

Video Media 3,150

Computer & Ins t rumen t Tape 550

F l e x i b l e Disks 653

R i g i d Disks 495 6,898

Growth

Percent

8

' 82 - ' 83

22

14

26

27

A complete summary o f pas t and p r o j e c t e d markets f o r r a d i a t i o n p rocess ing o f p o l y -

m e r i c m a t e r i a l s i n t h e U.S. i s shown i n Table 6-12.


As more and more i n d u s t r i e s c o n v e r t t o r a d i a t i o n p rocess ing techno log ies , t h e de-

mand f o r r a d i a t i o n p rocess ing equipment i nc reases p r o p o r t i o n a l l y .

t h a t r a d i a t i o n p rocess ing equipment (UV, h i g h energy e l e c t r o n , I R ) w i l l grow f r o m

approx ima te l y 3035 t o t a l p r o d u c t i o n u n i t s i n 1980-81 t o app rox ima te l y 8610 t o t a l

p r o d u c t i o n u n i t s i n t h e yea rs between 1986 t o 1990. The growth ( h i s t o r i c and

f u t u r e ) and major market usage f o r these p a r t i c u l a r r a d i a t i o n p rocess ing equipment

systems i s shown i n Table 6-13. (134)

It i s es t ima ted

6-31

Table 6-12

RADIATION PROCESSING OF POLYMERIC MATERIALS MARKETS AND GROWTH POTENTIAL

Wood Coatings Metal Coatings Packaging Coatings F1 oor Coatings W i re Coati ngs Flexible Plastics Elastomer Coatings Other Markets (Fiber Optics,

Sub Total (IPF Market Ranges)

Printing Inks Printing Plates Adhesives Electronics Magnetic Recording Materials

Sub Total (Predominately UV and Low Energy Electron Processing Operations)

Appl i cati ons

Ceramics, Textiles)

High Energy Electron Beam

Infrared Curing Applications

Total Dollar Value

Histories (1979-1985) Mi 11 ions. Mi 11 ions.

Rounds dol 1 ars

10-15 17-24 8- 10 24-30 2-8 6-22

10-16 32-50 0.1 - - 4-5 12-14 2 5-6

5-12 20-30

41-68 116- 176

18 54 8- 14 120-210 0.6 6.8-7.2 8-14 93-160

7 - -

76-115 281 -438

- - 400-700

lo - -

Future (19901 Millions, Mi 11 ions, pounds dol 1 ars

15-30 24-48 8-32 30-96 8-43 32-96 16-19 50-60

5-9 14-24 - - 0.1-0.2

2 6

12-20 30-50

66-155 176-398

54- 135 1 1 1 - 278 14-17 210-250 1.6 19

28 320 10 - -

98-182 670-877

- - 700-900

20 - -

691 - 1,148 1,390-1,797

6-32

Table 6-13

RADIATION PROCESSING EQUIPMENT (GROWTH AND MAJOR MARKET AREAS) (134) -

Approximate Number of P r o d u c t i o n U n i t s . . Process ing Equipment and Fo r a 'G iven Year

Major Market Area 1971 1976 i98o-ai 1986-1990

54 percen t i n p r i n t i n g o r 100 300 2100 4200 packaging, 23 percen t i n wood c o a t i n g s , 23 pe rcen t i n o t h e r appl i c a t i on areas

High Energy E l e c t r o n i c s

Major market areas a re i n h i g h speed c o a t i n g and g raph ics a r t s , adhesive l a m i n a t i o n , and polymer m o d i f i c a t i o n techno1 og ies

2 3 a5 210

850 4200 40 pe rcen t i n meta l c o a t i n g s ( t r a n s p o r t a t i o n ) 60 percen t i n p l a s t i cs , t e x t i l e s adhesives , c o a t i n g s (nonmetal 1, and t h e g r a p h i c a r t s i n d u s t r i e s - - - -

T o t a l 102 303 3035 a610

6-33

The p resen t and f u t u r e e l e c t r i c a l energy consumption requi rements f o r I R , UV, and h igh-energy e l e c t r o n process ing equipment can be c a l c u l a t e d assuming t h a t an aver-

age es t ima ted power c a p a c i t y r a t i n g pe r u n i t f o r each r a d i a t i o n processor c l a s s i f i -

c a t i o n (UV, EB and IR) i s 100, 50 and 250 kw r e s p e c t i v e l y . T h i s equates t o an

approximate p resen t t o t a l c a p a c i t y o f 426,750 kw f o r t h e 3035 1980-1981 p r o d u c t i o n

u n i t s and a f u t u r e c a p a c i t y p r o j e c t i o n o f app rox ima te l y 1,480,500 kw f o r t h e r a d i a -

t i o n p r o d u c t i o n u n i t s expected t o be i n p l a c e between 1986 and

1990. ( 16,123,134 , 150)

COMPETITION FROM EXISTING AND EMERGING TECHNOLOGIES

Severa l compet ing and emerging techno log ies a re assoc ia ted w i t h t h e c o a t i n g s t r y which impact t h e f u t u r e o f r a d i a t i o n p rocess ing systems. These compet ing

ndus-

coa t - i n g systems i n c l u d e conven t iona l low s o l i d s so lvent-based c o a t i n g s u s i n g s o l v - n t b u r n i n g o r r e c l a m a t i o n a n t i p o l l u t i o n techniques, h i g h s o l i d s c o n t e n t so lvent-based

coa t ings , water-based c o a t i n g s ( e l e c t r o c o a t i n g and n o n e l e c t r o c o a t i n g ) and 100%

s o l i d s powder c o a t i n g systems. A breakdown o f 1982 and p r o j e c t e d 1987 U.S. s h i p -

ments f o r t h e i n d u s t r i a l p roduc t f i n i s h i n g market o f t h e c o a t i n g s i n d u s t r y i s shown i n Tab le 6-14. From t h i s i n f o r m a t i o n i t appears t h a t t h e o t h e r c o a t i n g t e c h n o l -

og ies w i l l c o n t i n u e t o dominate t h i s p a r t i c u l a r market area. (47 ) - An energy analy-

s i s f o r c u r i n g these c o a t i n g systems shows t h a t r a d i a t i o n p rocess ing i s by f a r t h e most e f f i c i e n t process; however, energy c o n s e r v a t i o n i s n o t t h e o n l y f a c t o r d r i v i n g

t h e c o a t i n g i n d u s t r y t o u t i l i z e these thermal c u r i n g processes (Tab le 6-15). As l o n g as t h e r e i s an abundant supp ly o f f o s s i l f u e l , t h e c o a t i n g i n d u s t r y w i l l c o n t i n u e t o f i n i s h p roduc ts i n which t h e r e i s no va lue added o r manu fac tu r ing

advantage o t h e r than energy sav ings by conven t iona l thermal c u r e methods. (153)

6-34

Table 6-14

U.S. SHIPMENTS OF INDUSTRIAL FINISHES BY COATINGS MATERIALS AND SYSTEMS (47)

1982 1987a Coatinqs Material/Svstem M i l $ Percent M i l $ Percent

Sol ventborne 1670 65.6 830 34.6 Conventional 800 31.4 300 12.5

~ _ _ _ _ _ - __-- EPA conforming systems 870 34.1 530 22.1

Waterborne 500 19.6 800 33.3 Electrodeposit ion (ED) 100 3.9 150 6.3 Non - ED 400 15.7 650 27.0

Powder coatings 150 5.9 200 8.3

Radiation curable 70 2.8 120 5.0 U l t r a v i o l e t (UV) 55 2.2 70 2.9 Electron beam (EB) 15 0.6 50 2.1

High sol ids-1 i q u i d 156 6.1 450 18.8

Tota l 2546 100 2400 100

aThese values a r e i n constant 1982 d o l l a r s .

6-35

Table 6-15

ENERGY ANALYSIS OF COATING TECHNOLOGIES

Two Sol ven t Water- High E l e c t r o - Component Rad i a t i on

Based -- borne Sol i d s c o a t i n g Urethane Powder Curable

Energy requi rements 12 11-12 9-10 3 8 8- 10 1 t o c u r e 440 square f e e t o f 19-gauge meta l per minute ( m i l l i o n BTU's)

Percent energy 0 0-8% 16-25 75 33 16-33 90 sav ings

An emerging techno logy developed by Ashland Chemical Company u t i l i z e s a

low- temperature chemical c u r i n g c o a t i n g system based on b locked i s o c y a n a t e chem- i s t r y c a t a l y z e d b y a v o l a t i l e amine c a t a l y s t m a t e r i a l .

o f f e r s seve ra l advantages over b o t h r a d i a t i o n c u r a b l e c o a t i n g s and t h e r m a l l y cured c o a t i n g s systems.

be designed t o be 100% r e a c t i v e and i s cured b y pass ing t h e coated p roduc t through

a vapor o f t h e amine c a t a l y s t .

t o remove t h e s o l v e n t . Th i s vapor cu re system i s ope rab le f o r a wide v a r i e t y o f f l a t - and three-d imensional p roduc t c o n f i g u r a t i o n s . Both t h e automot ive and t h e

v i n y l f i l m i n d u s t r i e s use t h i s technology t o process c e r t a i n p roduc ts , and i n

A u s t r a l i a t h i s system has been adapted t o c u r e p r i n t i n g i n k s f o r a wide v a r i e t y o f

appl i c a t i ons . (154 - 1

T h i s vapor c u r e process

I n t h i s technology t h e c o a t i n g i s a p p l i e d f r o m s o l v e n t b u t c o u l d

No heat i s r e q u i r e d , except f o r what i s necessary

GLOBAL TRENDS FOR RADIATION PROCESSING OF POLYMERIC MATERIALS

European a c t i v i t i e s i n r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s a re m a i n l y con- cerned w i t h t h e development o f raw m a t e r i a l s and f i n i s h e d p roduc ts r a t h e r than w i t h

investments in i n d u s t r i a l p r o d u c t i o n equipment. A t p r e s e n t t h e r e a r e a p p r o x i -

m a t e l y 800 t o 2,000 UV; 80 t o 100 EB and 1,000 t o 2,000 I R i n s t a l l a t i o n s e x i s t i n g

th roughou t Europe; and i n 1990 t h e expected numbers are 4,200 UV, 210 EB and 4,200

I R r a d i a t i o n p rocess ing u n i t s r e s p e c t i v e l y . (134 , 155 , 156 1 Cur ren t p r o j e c t e d e l ec- t r i c power c a p a c i t y r a t i n g s f o r t hese p rocess ing u n i t s i s between 500,000 and

1,500,000 kw.

search, p i l o t and i n d u s t r i a l p r o d u c t i o n opera t i ons .

i n s t a l l a t i o n s i n many d i f f e r e n t f i e l d s of a p p l i c a t i o n s a long w i t h t h e i n t e n s e

The p resen t i n s t a l l a t i o n s a re be ing used i n a wide v a r i e t y o f r e -

The l a r g e numbers o f e x i s t i n g

6-36

a c t i v i t i e s o f raw m a t e r i a l s u p p l i e r s and manufactures o f p roduc ts do n o t a l l o w f o r

a r e l i a b l e e s t i m a t i o n o f t h e use o f these r a d i a t i o n c u r a b l e m a t e r i a l s i n Europe.

The t o t a l 1978-1981 va lue o f r a d i a t i o n c u r a b l e m a t e r i a l s f o r Europe i s es t ima ted t o

be between $300 t o $600 m i l l i o n and t h e va lue o f t hese m a t e r i a l s i n 1990 i s p ro -

j e c t e d t o be between $700 t o $950 m i l l i o n .

The c o a t i n g i n d u s t r y , p redomina te l y UV c u r a b l e c o a t i n g s , accounts f o r app rox ima te l y

20 t o 30% o f t h e t o t a l r a d i a t i o n c u r a b l e p roduc ts consumed i n Europe. The p r o d u c t

share breakdown percentages f o r t h i s p a r t i c u l a r i n d u s t r y a r e as -- __ __ l i n e s o r market

f o l l ows :

UV c u r a b l e coa t

EB c u r a b l e c o a t

wood c o a t i n g s meta l d e c o r a t i o n and p r i n t i n g i n k s

rigs paper and cardboard c o a t i n g s f l e x i b l e p l a s t i c and f l o o r c o a t i n g s o t h e r c o a t i n g systems

29 22 11 11 5

rigs 22 T o t a l li5rd-

I n Europe energy shor tages do n o t appear t o be a major m o t i v a t i o n f o r c o n v e r t i n g t o

r a d i a t i o n p rocess ing techno log ies over conven t iona l f o s s i l f u e l thermal c u r i n g

methods. Europe has access t o crude o i l f r om t h e M idd le East and A f r i c a , n a t u r a l gas f r o m t h e Nether lands, S o v i e t Union and N o r t h A f r i c a . The p r o d u c t i o n o f o i l and

gas f r o m t h e N o r t h Sea i s i n c r e a s i n g and c l a s s i c energy sources i n t h e f o r m o f ha rd

c o a l and l i g n i t e a re n e a r l y w i t h o u t l i m i t a t i o n s .

u c t manufacture v i a r a d i a t i o n p rocess ing techniques c e n t e r s on p r o d u c t i o n e f f i c -

i ency , p roduc t performance and va lue added m a t e r i a l s . (157,158)

The d r i v i n g f o r c e then f o r prod-

For example, r a d i a t i o n c u r a b l e c o a t i n g s on formed p a r t s has been i n p r o d u c t i o n

s i n c e 1981 i n a VW p l a n t i n Wolfsburg, Germany. wheel r i m ) i s f i n i s h e d w i t h an e l e c t r o n beam c u r i n g u n i t (200 KV, 40 mA, 32

Mrad/sec, 400 mm wide) u s i n g a c o a t i n g hav ing a r a d i a t i o n c u r e s e n s i t i v i t y o f 25

Mrad o r r a t e o f c u r i n g c a p a b i l i t y w i t h i n 0.8 sec. These p roduc ts (9400 mm diam-

e t e r , 200 mm h e i g h t , 10 Kg w e i g h t ) can be coated and cu red a t a p r o d u c t i o n r a t e

of between 6 and 22 r ims/min. a t a c o s t sav ings o f about 67% over t h a t of a conven-

t i o n a l t h e r m a l l y cu red c o a t i n g system (Table 6-16). (159) -

The p a r t i c u l a r coa ted p roduc t ( a

F u t u r e a p p l i c a t i o n s f o r r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s i n Europe w i l l

be i n c o a t i n g s f o r automot ive, meta l and p l a s t i c products ; t e x t i l e s , and adhesive

systems f o r a wide v a r i e t y o f s u b s t r a t e l a m i n a t i o n p roduc t c o n f i g u r a t i o n s .

6-37

Table 6-16

Cost Factor

COST COMPARISON OF ELECTRON BEAM TO HOT AIR CONVECTION CURING SYSTEMS FOR WHEEL RIMS (159)

Application Quantity Pai nted Surf ace/r im Coating Cost Overs p r ay Coating Thickness

Labor Reauirements

Utilities

Natural gas

Start-up loss Nitrogen cost Electric Energy cost Start - u p/S h u t down Lo s s

EauiDment Investment

(1000 BTU/cft) cost

Cost with Start-up Amortization time Financing Costs

Manufacturinq Area

Necessary Area Cost o f Area/year

TOTAL COST/Y EAR TOTAL COST/RIM (2,142,000 rims/year)

Hot Air Convection Curinq Svstem

100 grp2 0.16 m $2.45/1000 gr 30 percent 40 microns

1,480,000 Kcal/h $5.5/1000 cft 8 percent

127 Kw/h 0.06 Kw/h 12 percent

- - - -

$720,000 4 years 11 %/year

462 m2 $87/m2

$/year Percent of Total

19.95% $1 19,950

20.94% $125,820

12.26% $73,730

- -

3.02% $18,180

37.15% $223,300

6.68 % $40,190

$601,170 $0.281

$/year Percent of

EB Svstem Total

40 sr/f 0.16 m $6.20/1000 gr 30 percent 40 microns

- - 15m3/h $0. 28/m3 49 Kw/h 0.06 Kw/h 4 percent

200 kV, 60 mA 400 mm width $580,000 4 years 11 %/year

72 m2 $87/m2

30.28% $121,420

19.75% $79,200

- - 2.20%

$8,820

1.60% $6,430

44.85% $179,870

1.56% $6,260

$401,000 $0.188

6-38

I n Japan, r a d i a t i o n process ing o f po l ymer i c m a t e r i a l s i s b e i n g used f o r wood,

m e t a l , paper, p l a s t i c and automot ive c o a t i n g s and f o r i n k s . E l e c t r o n i c and commun-

i c a t i o n i n d u s t r i e s i n Japan a re a l s o h e a v i l y committed t o r a d i a t i o n p rocess ing

techniques i n a s i m i l a r manner as t h e i r U.S. and European c o u n t e r p a r t s . Japan i s

a l s o a major producer o f c r o s s l i n k e d w i r e , c a b l e and rubber p roduc ts f o r t h e u t i l -

i t y , computer and automot ive t i r e i n d u s t r i e s . (160,161)

A t t h e p resen t t ime i t i s es t ima ted t h a t t h e r e a re approx ima te l y 800 UV, 60-120 E6

and 800 I R r a d i a t i o n process ing u n i t s i n Japan. The t o t a l number o f p rocess ing

u n i t s i s expected t o reach 2,500 (1,100 UV, 175 E6 and 1,225 I R ) i n 1990. Cur ren t

and p r o j e c t e d e l e c t r i c power c a p a c i t y r a t i n g s f o r these p rocess ing u n i t s i s between

300,000 and 430,000 kw. U l t r a v i o l e t and I R p rocess ing equipment i s m a i n l y used t o f i n i s h i n k s and c o a t i n g s as p r e v i o u s l y desc r ibed f o r Europe and t h e

U.S. (134,162,163) The c u r r e n t number o f e l e c t r o n beam p rocess ing u n i t s (60 u n i t s

i n 1982) a re r a t e d a t an approximate t o t a l c a p a c i t y o f 2,400 kw and t h e d i f f e r e n t

a p p l i c a t i o n areas u t i l i z i n g t h i s technology are as f o l l o w s : (164) -

___ __ . - -

0 Research and Development 12 u n i t s (255 kw) 0 E l e c t r i c w i r e 20 u n i t s (1,000 kw) 0 Po lye thy lene foam 7 u n i t s (270 kw) 0 Heat -sh r inkab le sheet

and t u b i n g 8 u n i t s (350 kw) 0 Coat ings 1 u n i t (50 kw) 0 T i r e - r u b b e r sheet 6 u n i t s (350 kw) 0 Others 6 u n i t s (125 kw)

An i n t e r e s t i n g a p p l i c a t i o n o f e l e c t r o n beam cu red p a i n t systems f o r meta l c o i l

s tock i s desc r ibed i n Reference 165. I n t h i s p a r t i c u l a r a p p l i c a t i o n i t was found

t h a t t h e EB c u r e process and assoc ia ted c o a t i n g m a t e r i a l s s i g n i f i c a n t l y ou tpe r -

formed a conven t iona l thermal c u r e c o a t i n g system (Tab le 6-17). From these r e s u l t s

i t appears t h a t a t l e a s t one f a c t o r e f f e c t i n g t h e f u t u r e growth o f E6 c u r e proces-

s i n g t e c h n o l o g i e s i s t h e development o f new polymer and c o a t i n g m a t e r i a l s . These

new c o a t i n g m a t e r i a l s w i l l have t h e c a p a b i l i t y t o produce h i g h q u a l i t y f i n i s h e s f o r

r e f r i g e r a t o r s , microwave ovens and a i r c o n d i t i o n e r housing f i x t u r e s . A t t h e pres- e n t t ime , t h e r e a re more than t e n Japanese p a i n t and r e s i n manufacturers who engage

i n t h e development o f EB-cured p a i n t s and r e s i n s .

6-39

Table 6-17

COMPARISON BETWEEN EB CURING AND THERMAL CURING COATING SYSTEM ON ELECTROGALVANIZED STEEL (165) -

E l e c t r o n Beam Thermal Cured Thermal Cured E v a l u a t i o n Tests Cured Coa t ing A c r y l i c PV c

Gloss 85 80 45

S u r f ace hardness ( p e n c i l 1 --

S a l t sp ray r e s i s t a n c e

S t a i n r e s i s t a n c e

Heat r e s i s t a n c e

8H F-4H 2H

1500 h r s 240-500 h r s 240-500 h r s

Excel l e n t F a i r -poo r F a i r - p o o r

Excel l e n t F a i r Poor

The es t ima ted consumption va lues f o r r a d i a t i o n p r o c e s s i b l e m a t e r i a l s i n Japan i s

c u r r e n t l y between $100 and $400 m i l l i o n and c o u l d reach $800 m i l l i o n i n 1990.

The g l o b a l o r wor ldwide i n t e r e s t i n t h i s techno logy i s s t r o n g l y e v i d e n t f r o m t h e

F o u r t h I n t e r n a t i o n a l Meet ing on R a d i a t i o n Process ing h e l d i n Yugoslav ia i n 1982 (1661, which was at tended b y r e p r e s e n t a t i v e s f r o m a t l e a s t 35 d i f f e r e n t c o u n t r i e s .

The r a p i d growth o f r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s has been w e l l docu-

mented i n t h e U n i t e d S ta tes , Europe, and e s p e c i a l l y Japan.

r a d i a t i o n p rocess ing research and developments w i l l c o n t i n u e t o i n c r e a s e w e l l be-

yond t h e y e a r 1990.

G loba l i n t e r e s t i n

6-40

Sec t ion 7

CONCLUSIONS, FUTURE DEVELOPMENTS AND TECHNICAL V O I D S

I n t h e l a s t 15 yea rs t h e convers ion o f e l e c t r i c a l energy i n t o i n f r a r e d , u l t r a v i o l e t

as an e f f i c i e n t and economical method f o r m o d i f y i n g po lymer i c m a t e r i a l s . These

r a d i a t i o n m o d i f i e d polymer systems a r e assoc ia ted w i t h many d i f f e r e n t types o f

p roduc ts which a r e produced under a wide d i v e r s i t y o f manu fac tu r ing opera t i ons .

From a consumer p o i n t o f view, almost eve ry day we encounter a po l ymer i c p roduc t

t h a t has been manufactured o r processed by some fo rm o f r a d i a t i o n energy:

__. ___ and h i g h energy e l e c t r o n e lec t romagne t i c r a d i a t i o n has gained wor ldwide acceptance

0

0

0

0

0

0

0

0

0

0

0

@

@

0

Wood f u r n i t u r e ( I R o r UV c u r a b l e c o a t i n g s )

Beer/beverage can l a b e l s ( I R o r UV c u r a b l e i n k s )

Meta l p i p e coa t ings (UV c u r a b l e c o a t i n g s )

Packaging (paper, f o i l , f i l m ) (UV/EB i n k s and c o a t i n g s )

F l o o r c o a t i n g s (UV c u r a b l e c o a t i n g s )

P r i n t e d p u b l i c a t i o n s ( I R / U V c u r a b l e i n k s )

Graphic screen p r i n t i n g i n k a p p l i c a t i o n on m i r r o r s (UV c u r a b l e i n k s )

Foamed p l a s t i c i n s u l a t i o n (EB i r r a d i a t e d p l a s t i c s )

Adhesive tapes (EB cu red adhesives)

Rubber t i r e s (EB i r r a d i a t e d r u b b e r )

Food packaging (EB i r r a d i a t e d p o l y o l e f i n s )

Wire (EB i r r a d i a t e d p o l y o l e f i n s )

Telephone c a b l e / o p t i c a l f i b e r s (UV c u r a b l e c o a t i n g s )

Computers (UV/EB polymer r e s i s t m a t e r i a l s 1

Record ing tape (EB c u r a b l e c o a t i n g s )

I n t h e U n i t e d S t a t e s i t i s es t ima ted t h a t t h e t o t a l use o f r a d i a t i o n p r o c e s s i b l e

m a t e r i a l s i s va lued a t app rox ima te l y $0.7 t o $1.1 b i l l i o n and i s expected t o

7-1

i nc rease t o between $1.4 and $1.8 b i l l i o n i n 1990.

app rox ima te l y 3035 t o t a l r a d i a t i o n (UV, EB, I R ) p rocess ing u n i t s i n t h e U n i t e d

S t a t e s which are r a t e d a t a t o t a l ( c u m u l a t i v e ) c a p a c i t y o f 430,000 kw. I n 1990 t h e

t o t a l number o f p rocess ing u n i t s i s expected t o reach 8610 u n i t s f o r a t o t a l r a t e d

C u r r e n t l y t h e r e a r e

c a p a c i t y o f 1,500,000 kw. European and Japanese es t ima tes f o r r a d i a t i o n

p r o c e s s i b l e m a t e r i a l s a r e va lued a t app rox ima te l y $0.3 t o $0.6 and $0.1

b i l l i o n r e s p e c t i v e l y . These va lues should i nc rease t o $0.7 t o $0.95 b i l

(Europe) and $0.8 b i l l i o n (Japan) i n t h e year 1990. The t o t a l number o f

p rocess ing u n i t s f o r Europe i s app rox ima te l y 2990 u n i t s (500,000 kw t o t a

o $0.4 i on

r a d i a t

capac - _. . ._ .. -

r a t i n g ) and approx ima te l y 1690 u n i t s (300,000 kw t o t a l c a p a c i t y r a t i n g ) a r e c u r r e n t l y i n s t a l l e d i n Japan. I n t h e year 1990 t h e number o f u n i t s i s expected

on

t Y

t o i n c r e a s e t o 8610 (1,500,000 kw c a p a c i t y r a t i n g ) and 2500 (430,000 kw t o t a l c a p a c i t y r a t i n g ) f o r Europe and Japan r e s p e c t i v e l y .

The g l o b a l commercial success o f r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s i n

many d i v e r s e a p p l i c a t i o n areas can be a t t r i b u t e d t o t h e f o l l o w i n g f a c t o r s :

Value added p roduc t ( r a d i a t i o n c u r a b l e polymer t e c h n o l o g i e s can m o d i f y low c o s t and low q u a l i t y s u b s t r a t e m a t e r i a l s i n t o h i g h performance p roduc ts ) .

Higher q u a l i t y p roduc t ( b e t t e r du rab i 1 i t y o r g r e a t e r pe r fo rm- ance c a p a b i l i t i e s ) .

High speed manufacture/ low scrap

Product cannot be manufactured by t i v e s u b s t r a t e and p roduc ts assoc i c s i n d u s t r i e s 1.

EPA p o l l u t i o n requi rements.

oss.

any o t h e r method (hea t s e n s i - a ted w i t h t h e m i c r o e l e c t r o n -

E l i m i n a t i o n o f s o l v e n t appl ied/ removal c o a t i n g systems ( reduc- t i o n i n m a t e r i a l i n v e n t o r y , r e d u c t i o n i n f i r e hazards and e l i m - i n a t i o n o f concerns about t h e a v a i l a b i l i t y o f s o l v e n t s ) .

Reduct ion i n energy cos ts .

The t o t a l impact o f r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s , w h i l e s i g n i f i c a n t ,

i s s t i l l a m ino r p a r t o f t h e t o t a l p roduc t manu fac tu r ing techniques c u r r e n t l y i n

use today. The o v e r a l l annual growth r a t e f o r r a d i a t i o n p rocess ing techniques i s p r o j e c t e d t o be between 10 t o 20%, thus i t i s an a t t r a c t i v e area f o r f u t u r e

7-2

research and development a c t i v i t y . Several f u t u r e developments expected f o r t h i s techno logy can be desc r ibed as f o l l o w s :

0 Cont inued research i n h i g h energy phys i cs d i r e c t e d a t e l e c t r o n beam a c c e l e r a t o r s f o r beam propagat ion, maintenance and c o n t r o l .

0 Cont inued research and development i n UV and I R p rocess ing equipment.

0

0

Development o f new r a d i a t i o n s e n s i t i v e po l ymer i c m a t e r i a l s .

Development o f new speci a1 t y p roduc ts and markets f o r r a d i a t i o n p rocess ing techno log ies .

o r p roduc t f i n i s h e r .

_ _

0 Reduct ion i n m a t e r i a l c o s t s ( l ower c o a t i n g c o s t s ) t o t h e use r

A t t h e p resen t t ime, most o f t h e e x i s t i n g r a d i a t i o n p rocess ing equipment i s capable

of meet ing t h e demands o f c u r r e n t p roduc t p rocess ing o p e r a t i o n s . n i c a l v o i d s t o be addressed i n t h e f u t u r e a re i n t h e areas o f new m a t e r i a l s deve l -

opment and s c i e n t i f i c unders tand ing ' o f t h e complex p h y s i c a l and chemical f a c t o r s

assoc ia ted w i t h polymer network fo rma t ion , c o a t i n g - s u b s t r a t e adhesion phenomena and

t h e d u r a b i l i t y o f r a d i a t i o n processed po lymer i c m a t e r i a l s under l ong - te rm m u l t i p l e

s t r e s s environments.

desc r ibed as f o l 1 ows :

The major t ech -

S p e c i f i c f u t u r e research goals f o r t h i s techno logy can be

0 Development o f new n o n t o x i c , low v i s c o s i t y , 100% r e a c t i v e monomer and o l i gomer m a t e r i a l s f o r use i n r a d i a t i o n c u r a b l e c o a t i n g systems . Development o f new adhesion promot ion monomer , o l igomer and p o l y m e r i c m a t e r i a l s f o r use i n r a d i a t i o n c u r a b l e c o a t i n g systems a p p l i e d t o meta l s u b s t r a t e s .

0

0 Development o f new r e s i s t m a t e r i a l s f o r e l e c t r o n i c and o p t r o n i c a p p l i c a t i o n s .

0 Long te rm aging s t u d i e s o f r a d i a t i o n processed polymers and c o a t i n g s i n o rde r t o e s t a b l i s h a r e a l i s t i c expected s e r v i c e l i f e p r o j e c t i o n c a p a b i l i t y .

The p resen t b e n e f i t s f r o m r a d i a t i o n p rocess ing o f po l ymer i c m a t e r i a l s a re d e r i v e d

f r o m improved q u a l i t y , s p e c i a l p r o p e r t i e s and h i g h e r p r o d u c t i v i t y . The advantages

o f low-energy consumption and low p o l l u t i o n a re g e n e r a l l y secondary c o n s i d e r a t i o n s b u t t h i s c o u l d change d r a m a t i c a l l y depending on EPA r u l i n g s and a v a i l a b i l i t y o f

f o s s i l f u e l s u p p l i e s . Increased usage o f r a d i a t i o n p rocess ing o f po l ymer i c systems

w i l l depend on m a t e r i a l c o s t s and address ing t h e t e c h n i c a l v o i d s d iscussed above,

7-3

as w e l l as, t h e e f f e c t s o f competing techno log ies w i t h i n s p e c i f i c market areas.

However, t h e r a p i d cure, low process ing temperatures, and development o f spec i a1 t y

produc ts w i l l i n s u r e t h a t r a d i a t i o n process ing t e c h n o l o g i e s w i l l c o n t i n u e t o grow

i n importance th roughout t h e wor ld .

7-4

S e c t i o n 8

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I . Sakamoto, Radiat ion Physics Chemistry, Vol . 22, Nos. 3-5, 1983,

I . Sakamoto, Reference 159, pp. 12-1-12-11.

pp. 947-953.

A. Chapiro, Reference 164, Nos. 1-2, pp. 7-10.

8-8

Appendix A

MANUFACTURERS OF RADIATION PROCESSING EQUIPMENT AND MATERIAL SUPPLIERS

INFRARED SYSTEMS PHOTOINITIATORS

Soneko, Inc. 87 E l i zabe th Avenue Somerset, NJ 08873 (201 ) 873-2217

ULTRAVIOLET SYSTEMS

Canrad-Hanovia, Inc. 100 Chestnut S t r e e t Newark, NJ 07105 (201) 589-4300 ~ 2 0 8

Aceto Chemical Co., Inc. 126-02 Northern Boulevard Flushing, NY 11368 ( 718 1 898-2300

Ciba-Geigy Corporat ion 3 Sky l i ne Dr ive Hawthorne, NY 10532 (914) 347-4700

MONOMERS

Fusion UV Curing Systems D i v i s i o n of Fusion Systems Corporat ion 7600 Standish Place Westtown Road a t W. Chester Pike Rockv i l l e , MD 20855 West Chester, PA 19380

ARCO Spec ia l t y Chemicals D i v i s i o n o f ARCO Chemical Company

(301 ) 251-0300 (215) 692-8400

Union Carbide Corporat i on Linde D i v i s i o n 5705 W. Minnesota Ind ianapol is , I N 46421 ( 317) 214-1200

HIGH ENERGY ELECTRON SYSTEMS

Energy Sciences I n t e r n a t i o n a l D i v i s i on of Energy Sci ences Incorporated 109, Rue de Lyon 1211 Geneva 13 Swi tzer land 22 - 45 -88- 21

RPC I n d u s t r i e s 3210 Investment Boulevard Hayward, CA 94545 (415 785-8040

Cel anese Chemical Company 1250 W. Mockingbird Dal las, TX 75247

Diamond Shamrock Chemicals /Co. D i v i s i o n o f Diamond Shamrock Corp. 350 M t . Kemble Avenue Morristown, NJ 07960-1931

(214) 689-4000

(201) 267-1000

Morton Chemical D i v i s i o n of Morton Thiokol , Inc. 101 Carnegie Center Princeton, NJ 08540 ( 609) 396-4001

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OLIGOMERS POLYMERS

ARCO S p e c i a l t y Chemicals D i v i s i o n o f ARCO Chemical Company Westtown Road a t W. Chester P i ke West Chester, PA 19380 (215 ) 692-8400

Diamond Shamrock Chemicals Co. D i v i s i on o f D i amond Shamrock Corpor a t i on 350 M t . Kemble Avenue Morr is town, NJ 07960-1931

L o r d C o r p o r a t i o n I n d u s t r i a l Coa t ing D i v i s i o n 2000 West Grandview Boulevard E r i e , PA 16514

Morton Chemical D i v i s i o n o f Morton Th ioko l , I n c . 101 Carnegie Center P r ince ton , NJ 08540

(201) 267-1000 ~ _ _ _ ~

(814) 868-3611

(609) 396-4001

ARCO S p e c i a l t y Chemicals D i v i s i o n of ARCO Chemical Company Westtown Road a t W. Chester P i k e West Chester, PAa 19380 (215 ) 692-8400

Cel anese Chemical Company 1250 W. Mock ingb i rd D a l l a s , TXx 75247 (214) 689-4000

L o r d C o r p o r a t i o n I ndus tr i a1 Coa t i ngs D i v i s i on 2000 West Grandvi ew Boulevard E r i e , PAa 16514 (814 ) 868-3611

Morton Chemical D i v i s i o n o f Morton T h i o k o l , I n c . 101 Carnegie Center P r ince ton , N J 08540 (609 ) 396-4001

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