powder polyester resins for excellent corrosion protection · powder polyester resins for excellent...

Powder Polyester Resins for Excellent Corrosion

Protection.

Based on paper by: Dana Ionescu, Gert Dijkstra, Hans Hettinga, Marcel Schutte, Menno Claasen

Robert van den Berg Jeths . Technical Application Manager

Abrafati Sao Paulo 16,17,18 September 2013

A effectively, efficiently and eco-friendly

solution to counter corrosion

Page PIMC Abrafati 16,17,18, September 2013

Content

• Introduction

• Background

• Experimental part

• Application properties and results

• Conclusions

• Value Proposition


Corrosion protection is a key requirement for steel in numerous applications

Automotive

Small parts

Metal Furniture

Shelving

Appliances

HV/AC

Construction

ACE

Corrosion

Protection

Key Requirement

in most steel

applications

Page PIMC Abrafati 16,17,18, September 2013 3

Corrosion

• If you are able to

stop the access of

oxygen, water and

other ions to the

metal you provide an

effective barrier

against corrosion

Source: http://www.chem1.com/acad/webtext/elchem/ec7.html


Corrosion protection through enhanced coating barrier properties

Corrosion can be controlled by providing a barrier against the passage of

ions and/or oxygen and water.

The lower the permeability of the coating for these species, the better

the barrier properties.

Other important properties to provide an efficient barrier are: Wetting

properties, Mechanical properties & Flexibility.

All the above mentioned properties depend on the coating’s constituents,

the most important in this respect being the resin.

Permeability

of species

hydrophobicity

Surface wetting

substrate

(organic) coating Mechanical

stresses


Finding a relation between Electro chemical impedance and Neutral Salt Spray

Testing methods used

• Accelerated test – Neutral Salt Spray (NSS)

According to ISO 9227, performed for 500 & 1000

hours

Progression of corrosion is measured after

damaging the coating

• Electrochemical Impedance

Spectroscopy (EIS)

Electrical resistance of intact coating is measured.


Methods - EIS • Intact coating: Electrical Impedance Spectroscopy (EIS)

– Electrochemical method

– Impedance resistance of altering current (Z [Ω])

– Capacity (C) of the coating (a.o. layer thickness dependent)

– Barrier properties and indicator for water uptake

– Measured with a Zahner Zennium (COLT Method)

• Storage for 14 day in:

– Humidity chamber

(40 °C / 100% rel. humidity)

– Demi. water (25 °C)

– 5 % NaCl solution (25 °C)

• Recording: (10 mHz – 100 KHz)

– 0 h (baseline)

– 14 d (value)

• Result: Remaining impedance after 14 d


Methods - NSS

• Damaged coating (controlled way): Neutral Salt Spray (NSS)

• Method: ASTM B117

• Conditions

– 35 °C

– 5 % sodium chloride solution

– 500h (or longer)

• Result:

– Corrosion from creep [mm]

• Substrate: R 46 cold rolled steel


Effect of cure on coating impedance

Loss of Impedance after 14 days of humidity test

Conclusion: Sufficient cure is very important to reach max impedance


T

9

The importance of proper cure


T

10

The importance of proper cure

Standard 70:30 Hybrid after 480 hrs NSS


Effect of resin/crosslinker ratio on EIS

Loss of Impedance after 14 days of humidity test

Conclusion:- Stoichiometric resin/crosslinker ratio is very important to obtain

the best Impedance resistance

- Deviation from stoichiometry (under/over) influences

the impedance negatively


Effect of resin/crosslinker ratio on NSS

Conclusion: -Stoichiometric resin/cross linker ratio is very important to obtain

the best corrosion resistance

- Deviation from stoichiometry (under/over) influences the corrosion

resistance negatively

- For the influence of the resin/cross linker ratio is a clear correlation

between NSS & EIS


Effect of PVC on EIS

0

20

40

60

80

100

0.0

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

25.0 0.

05.

07.

510

.012

.515

.017

.520

.022

.525

.0

PVC [%v]

Perc

en

tag

e o

f

ori

gin

al

Imp

ed

an

ce [

%]

Kronos 2160 Blanc fixe Super FLayer thickness:

70 - 80µm

Loss of Impedance after 14 days of 5% NaCl

Conclusion: Too high or too low PVC for TIO2 & Filler results in less barrier

properties


Effect of PVC - NSS

0

2

4

6

8

10

12

5.0 12.5 25.0 clear coat 5.0 12.5 25.0

Amount of filler / pigment [%v]

co

rro

sio

n c

reep

[m

m]

Kronos 2160 Blanc fixe Super F

Layer thickness:

70 - 80µm

Conclusion:

-Clear coats have a worse corrosion resistance than pigmented coatings

- Increasing amounts BaSO4 fillers & TIO2 have a positive influence

on the corrosion resistance


Effect of pigment type - EIS


Conclusion: -Surface treatment of TiO2 pigment can have a large impact

on barrier properties of a coating. Hydrophobic pretreatment of pigments is

bad for the barrier properties of a coating


Effect of pigment type - NSS

Conclusion: surface treatment of TiO2 pigment can have a large impact

(pos/neg) on corrosion resistance


Effect of fillers on EIS

0

20

40

60

80

100

Kronos

216

0

Aeroxid

e LE

1 2.

5%

Aeroxid

e LE

1 5.

0%

Aeroxid

e LE

1 7,

5%

Blanc

fixe

Sup

er F

Diam

elia 4

0/10

Albaw

ithe

60

EWO

Porta

ryte

15

Om

yaca

rb 5

GU

Durcal 5

Mar

tinal

ON 3

10

Porta

fill A

40

Micr

o Talc

AT 1

Micr

o M

ica

W1

Lith

opon

e 30

% D

S

Different types of fillers (PVC 13%v)

Perc

en

tag

e o

f

ori

gin

al

Imp

ed

an

ce [

%]

BaSO4 CaCO3 Al(OH)3Layer thickness:

70 - 80µm


Conclusion:

-Correct filler choice is important for good barrier properties

-CaCO3 & Al(OH) are better for barrier properties than TiO2 and BaSO4

-FeO3 gives very poor barrier properties


Effect of fillers - NSS

0.0

2.0

4.0

6.0

8.0

Kro

nos 2

160

Aer

oxide

LE 1

2.5

%w

Aer

oxide

LE 1

5.0

%w

Aer

oxide

LE 1

7.5

%w

Blanc

fixe

Sup

er F

Dia

melia

40/1

0

EW

O

Albaw

ithe

60

Bar

ista

r 901

5

Por

tary

te 1

5

Om

yaca

rb 5

GU

Durc

al 5

Mar

tinal O

N 3

10

Por

tafill A

40

Micro

Talc

AT 1

Micro

Mica W

1

Lith

opon

e 30

% D

S

Different filler (PVC 13%v)

co

rro

sio

n c

reep

[m

m]

> 10 mm

Layer thickness:

70 - 80µm

BaSO4 CaCO3 Al(OH)3

Conclusion: -Correct filler choice is important for corrosion resistance

-FeO3 & Talc give very poor corrosion resistance


Effect of additives - EIS

0

20

40

60

80

100

Byk 3

60 P

Addito

l XL

496

Byk 3

68

Mod

aflow

Pow

der 2

000

Mod

aflow

Pow

der I

II

Resiflo

w PV 8

8

Byk 3

951

P

Ceraflo

ur 9

93

Ceraflo

ur 9

70

Chinam

att 1

200

Different additives

(PVC 5%v Blanc fixe Super F)

Per

cen

tag

e o

f

ori

gin

al I

mp

edan

ce [

%]

flow degassing matting

Layer thickness:

70 - 80µm


Conclusion: - Flow agents, degassing & matting agents can have a negative

influence on barrier properties of a coating

-Resiflow PV88 & Chinamatt 1200 are very poor for the barrier properties of a

coating


Effect of additives - NSS

0.0

2.0

4.0

6.0

8.0

10.0

-

Byk 3

60 P

Addito

l XL

496

Byk 3

68

Mod

aflofw

200

0

Mod

aflow

III

Resiflo

w PV 8

8

Byk 3

951

P

Ceraflo

ur 9

93

Ceraflo

ur 9

70

Chinam

att 1

200

Different additives (PVC 13%v)

corr

osi

on

cre

ep [

mm

]

Layer thickness:

70 - 80µm

flowdegassing matting

Conclusion: - Flow agents, degassing & matting agents can have a negative

influence on the corrosion properties of a coating


Use of anti-corrosive pigments - EIS

0

20

40

60

80

100

0.0 2.5 5.0 7.5 10.0

Amount Shieldex® C 303 [%w]

Perc

en

tag

e o

f

ori

gin

al

Imp

ed

an

ce [

%]

Layer thickness:

70 - 80µm

Conclusion: > 10% shieldex anti corrosion pigment has a negative influence on

the barrier properties of a coating


Use of anti-corrosive pigments - NSS

0.0

1.0

2.0

3.0

4.0

0.0 2.5 5.0 7.5 10.0

Amount Shieldex C 303 [%w]

co

rro

sio

n c

reep

[m

m]

Layer thickness:

70 - 80µm

Conclusion: In NSS Shieldex appears to have a small positive effect, optimum is

5%, however gloss and mechanical properties are affected > 2.5% added


Results – Single layer application non pre-treated R 46

Uralac® P 7604 & Uralac® P 7604 performs significantly better than reference

FBE systems after 500 hours in neutral salt spray (NSS) test according ISO 9227


Key properties compared to other systems (white Single layer)

Key properties Standard

70/30 Hybrid

Uralac® P

7630 70/30

Standard

95/5 Primid

Pure Epoxy Uralac® P

7604

96/4 Primid

Flow (PCI)* 6 6 6 5-6 5

Impact (5/8” ball) 160 IP 160 ip 160 IP 160 IP 160 IP

Cupping test (ESP) > 8 mm > > 8 mm > 8 mm > 8 mm

Cross cut (Gitterschnitt) Gt0 Gt0 Gt0 Gt0 Gt0

Gloss retention (QUV-B) 50-100 hrs 50-100 hrs 400-500 hrs 50-100 hrs 200-250 hrs

Storage 28 days 40˚C * 9 9 9 n.a. 9

Degassing limit n.a. n.a. 125 µm n.a. 125 µm

Salt spray (NSS) 500 hrs 4-7 mm 1-2 mm 4-5 mm 2-3 mm 2 mm

Humidity, 720 hours n.a. Pass n.a. n.a. Pass

Curing cycle 10 min 180ºC 12 min 180ºC 10 min 180ºC 12 min 180ºC 15 min 180ºC


Coated on 2,5 mm bare (un-cleaned) construction steel panels after 500 hrs NSS (DIN 9227)

Pure epoxy Uralac® P 7604

Uralac® P 7604 gives similar performance to pure epoxy on bare steel

In above example corrosion takes places because bare steel is not cleaned

Non coated original panel

Panels in duplo Panels in duplo


Same test on grid blasted panels after 500 hrs NSS

Non coated original panel Pure epoxy Uralac® P 7604

Uralac® P 7604 gives similar performance to pure epoxy on grid blasted steel

Much less corrosion, due to proper cleaning of steel by grid blasting

proper cleaning remains important, independent of coating system applied

Panels in duplo Panels in duplo


Comparison inter-coat adhesion using pull off test

27


Inter-coat adhesion

28

Conclusion: - Inter-coat adhesion between Corres primer and top coat is

comparable or better than FBE primer and topcoat


Conclusions (I)

29

There is a clear correlation between EIS & NSS. To reach

maximum resistance (barrier properties) it is very important to:

1. Cure sufficiently

2. Use stoichiometric resin/cross linker ratio. Deviation (over/under) has

a negative influence

3. Use the correct pigments or fillers. a) Clear coatings have less

resistance compared to pigmented coatings and b) Surface treatment

of the TiO2 has a big influence (Hydrophobic has a negative effect)

4. Use the correct PVC, too high or too low TiO2/Filler results in

decreasing properties

For Cold rolled steel, Uralac® P 7630 is the best primer for corrosion

resistance! (in comparison with primers based on pure epoxy or hybrid system)


Conclusions (II)

30

The influence of the powder formulation is crucial. Keep in

mind the following:

1.CaCO3 and Al(OH)3 are better for barrier properties than TiO2 and BaSO4

however FeO3 is worst

2.FeO3 and Talc also have negative influence on corrosion resistance

3.Flow-, degassing- and matting agents can decrease the impedance &

corrosion resistance, resulting in worse barrier properties

4.Resiflow PV-88 and Chinamatt 1200 are negative for the barrier

properties of the coating

5.Addition of > 10% Shieldex (anti-corrosion pigment) shows a decrease in

resistance instead of the expected improvement

5b. 5% has a small positive effect on NSS, however gloss and mechanicals

are affected > 2,5%

6. Inter-coat adhesion between Corres primer and top coat is comparable

or better than FBE primer and topcoat


Value Proposition corrosion protective coatings

DSM Paint

producers

Applicators

OEM / Job End users

Eco friendly coating

New business

Sustainable business

Reduce / skip pre-treatment

More secure, more forgiving

Less chemicals and waste

Good performance

Lower total system costs

Uralac® P 7604 Uralac® P 7630 significantly reduces and sometimes

completely eliminates chemical pre-treatment steps. In turn it improves

operational efficiency by:

skipping / reducing the number of chemical pre-treatment steps

reducing the amount of pre-treatment chemicals

reducing process waste

Uralac® Corres adds value throughout the metal coatings supply chain:


DSM Paint

producers

Applicators

OEM / Job End users

Epoxy free

Equal performance

Lower system costs

Epoxy free

Equal performance

Reduced delaminating risk

Value Proposition epoxy-free primers

As epoxy-free primer Uralac® P 7604 performs equal to conventional epoxy-

based systems, but with much better environmental footprint, reduced risk of

delaminating between layers and lower system costs:

epoxy-free eco-friendly primer system

good corrosion performance, reduced delaminating risk

lower system costs and less price volatile

Uralac® Corres adds value throughout the metal coatings supply chain:


Available Uralac® Cores™ Products

33


Further Work

• At this moment a program is running to apply the same

technological principles to other powder paint systems.

• Possible next developments:

– a Polyester for TGIC cure

– an outdoor durable Polyester

We will keep you informed!


Preview CORRES™ TGIC system

35


THANK YOU

for your attention!

powder polyester resins for excellent corrosion protection · powder polyester resins for excellent...

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