polyasparticcoatings - latest developments for extending...

Polyaspartic Coatings -Latest developments for extending performance

PDA Europe Conference,

Vienna, November 18-20 2008

.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 2

Do Polyaspartic Coatings fit into the PDA ?

Yes !Polyurea is not a singular product made out of aliphatic polyether-amines and MDI-based prepolymers

Polyurea offers a wide range of properties and Polyaspartic Coatings are just one example out of manys

Pure polyurea as pure Polyaspartic Coatings are only based on amine-terminated resins and isocyanate prepolymers


OO

O

O

R'

R'OO

O

O

R'

R'

NH

XNH

Structure of polyaspartic esters

Product Solid content Equivalent weight

Viscosity mPas

Reactivity

Desmophen NH 1520 100% 290 1500 low Desmophen NH 1420 100% 276 1500 mid Desmophen NH 1220 100% 234 100 high

Polyaspartic Esters


Reaction to a Polyaspartic Coating

OO

O

O

N

R1

R2+ R3

N C O R3OO

O

O

R1 NC

NH

R2

O

H

Aspartic ‘Polyaspartic Coating’

R1

R1

Aliphatic polyisocyanate


Known properties of Polyaspartic Coatings

- Fast curing , improved productivity

- Variable cure speed , 2 min → 40 min

- Low VOC , 80 → 99.x % solid content (near zero VOC)

- Thin to moderate film build , 100 → 600 µm

- Color and UV stable

- Hard, durable film , very good abrasion resistance


Still open questions

- How to make flexible films ?

- How to speed up reactivity without changing the materials ?

- How to extend pot life ?

- How to increase chemical resistance ?

- How to increase film thickness ?

- How to reduce the viscosity ?

- How to reduce raw material cost ?



- How to make flexible films ?

Ideas : - Plasticizer

- Polyol combinations

- New polyasparticester

- Isocyanate modifications



- How to make flexible films ? Plasticizer use

4%30

3.5%20

3%10

% Elongation @ break% Plasticizer

Effect on elongation

-337% Plasticizer

-205% Plasticizer

-4Control

% Gloss loss (60º) 1000-hours



- How to make flexible films ? Plasticizer use

Advantages : · Can reduce viscosity· Does not influence reactivity

Disadvantages : · Effect on elongation very poor· Can weaken the light stability· Will squeeze out of the film at

elevated temperatures

Summary : Not recommended



- How to make flexible films ? Polyol combinations

Options : - Polyester-polyoles → to be tested

- Polyether- polyoles → negative influence on UV stability(chalking/cracking)

- NOPs → 2 NOPs tested, incompatibility

- Polyacrylate-polyoles → solvent free products to high in viscosity




Polyester-polyol , example

120%50% polyester polyol



% Elongation @ break% Modification



0

10000

20000

30000

40000

50000

60000

0 5 10 15 20 25 30 35

visc

osity

(mPa

·s)

time (min)


Polyester-polyol , example




Polyester-polyoles

Advantages : · Does influence elongation· Can increase light stability

Disadvantages : · Still a high amount needed· Compatibility has to be tested

for each product

Summary : In general polyol combinations are not recommended



- How to make flexible films ? New Polyasparticester

· New experimental products were developed.

· Very good influence on the elongation

· Fast and moderate reactivity possible

· But registration issues in the EU and other regions / countries

Summary : For the time being not an option in most parts of the world



- How to make flexible films ? Isocyanate modifications

Standard isocyanate : · Low viscose asymetric HDI trimer Desmodur XP 2410NCO : 23.5 % , viscosity @ 23°C : 700 mPa·s, F = 3.x

Possible modifications : · HDI-oligomer Desmodur N 3400NCO : 22 % , viscosity @ 23°C : 150 mPa·s

· symetric HDI-trimer Desmodur N 3600NCO : 23.5 % , viscosity @ 23°C : 1200 mPa·s

· modified HDI-trimer Desmodur N 3800NCO : 11 % , viscosity @ 23°C : 6000 mPa·s

· HDI-/IPDI-polyisocyanate Desmodur NZ1NCO : 23.5 % , viscosity @ 23°C : 700 mPa·s

· HDI-polyether-prepolymer Desmodur XP 2599NCO : 6 % , viscosity @ 23°C : 2500 mPa·s




< 2%Standard

100 %HDI-polyether-prepolymer

< 2%HDI-/IPDI-polyisocyanate

110 %Modified HDI-trimer

< 2%Symetric HDI-trimer

160 %HDI-oligomer

% Elongation @ breakModification (100%)




Modification with modified HDI-trimer

110%100%40 %75%10 %50%5 %25%

< 2 %0% Elongation @ break% Modification




Modification with modified HDI-polyether-prepolymer

70 %75%

6 %50%

4 %25%

%Elongation @ break% Modification




Advantages : · Does influence elongation· Can decrease viscosity· Mechanical properties can be adjusted by

blending different isocyanates· Can reduce viscosity

Disadvantages : · Handling of another raw material

Summary : Modification of choice



- How to speed up reactivity without changing raw materials ?

· Tertiary amines e.g. Addocat® PP from RheinChemie Rheinau GmbH

· Light stabilizer combinations e.g. Ciba® TINUVIN® 292 / 1130 (1:1)from Ciba Specialty Chemicals Inc.

Remarks : - DBTL will reduce the reactivity- The “right” amount has to be tested with the

actual formulation



- How to extend pot life ?

· Oxazolidines e.g. Hardener VP LS 2959or Incozol 2from Industrial Copolymers Ltd

· Molecular sieve powder 4Å e.g. Sylosiv® A4from W. R. Grace & Co

15 minStandard

60 minSylosiv A4 , 1.5 % on formulation

23 minOxazolidine , 0.75 % on formulation

Pot life @ 23°C , min



- How to increase chemical resistance ?

· Combination with other polyoles : Not an optionSee page 10 – 13

· Increase cross linking NCO : NH : ≥ 1.5Only suitable option right now

Important Note : Existing patent for the USA



- How to increase film thickness ?

The limitation of the film thickness, approx. 300 µm roller application, is based on humidity/moisture influences during the curing time.

· Molecular sieve powder 4Å e.g. Sylosiv® A4from W. R. Grace & Co

· Degasing : degasing of the comp. B (polyisocyanate)increases the max. DFT due to higher solubility of CO2 in the liquid coatingmaterial



- How to reduce viscosity ?

· Reactive diluents : Aldimines / Ketiminese.g. Desmophen LS 2963A + VP LS 2142limitation @ approx. 5% addition due torapid skin formation and yellowing

· Isocyanate combinations : a blend with a low viscose isocyanate, e.g. Desmodur N 3400

· Plasticizer : not an option, see page 9

· Solvents : due to VOC regulation in most casesnot an option



- How to reduce raw material costs ?

That‘s something for the future far, far away ……☺

polyasparticcoatings - latest developments for extending...

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