Polyaspartic Coatings Latest developments for extending performance
PDA Europe Conference, Vienna, November 18-20 2008
Do Polyaspartic Coatings fit into the PDA ?
Yes ! Polyurea is not a singular product made out of aliphatic polyetheramines 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 amineterminated resins and isocyanate prepolymers
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 2
Polyaspartic Esters
O
O R' R'
H N
O
X
H N
O O
O
R' R'
O
O
Structure of polyaspartic esters
Product
Solid content
Equivalent weight
Viscosity
Reactivity
mPas
Desmophen NH 1520
100%
290
1500
low
Desmophen NH 1420
100%
276
1500
mid
Desmophen NH 1220
100%
234
100
high
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 3
Reaction to a Polyaspartic Coating
O R1
N
O R1
H
O
O R2
R1 +
R3
N C O
R2 N
O O
C
H N
R3
O
R1
O Aspartic
O Aliphatic polyisocyanate
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 4
‘Polyaspartic Coating’
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
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 5
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 ?
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 6
Still open questions
- How to make flexible films ? Ideas :
- Plasticizer - Polyol combinations - New polyasparticester - Isocyanate modifications
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 7
Still open questions - How to make flexible films ?
Plasticizer use
Effect on elongation % Plasticizer
% Elongation @ break
10
3%
20
3.5%
30
4%
% Gloss loss (60º) 1000-hours Control
-4
5% Plasticizer
-20
7% Plasticizer
-33
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 8
Still open questions - 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
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 9
Still open questions
- How to make flexible films ?
Options :
Polyol combinations
- 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
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 10
Still open questions
- How to make flexible films ?
Polyol combinations
Polyester-polyol , example
% Modification
% Elongation @ break
15% polyester polyol
4%
33% polyester polyol
94%
50% polyester polyol
120%
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 11
Still open questions
- How to make flexible films ?
Polyol combinations
Polyester-polyol , example 60000
viscosity (mPa·s)
50000 40000 30000 20000 10000 0 0
5
10
15
20
time (min)
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 12
25
30
35
Still open questions
- How to make flexible films ?
Polyol combinations
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
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 13
Still open questions
- 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
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 14
Still open questions - How to make flexible films ?
Standard isocyanate :
Isocyanate modifications
· Low viscose asymetric HDI trimer Desmodur XP 2410 NCO : 23.5 % , viscosity @ 23°C : 700 mPa·s, F = 3.x
Possible modifications :
· HDI-oligomer Desmodur N 3400 NCO : 22 % , viscosity @ 23°C : 150 mPa·s
· symetric HDI-trimer Desmodur N 3600 NCO : 23.5 % , viscosity @ 23°C : 1200 mPa·s
· modified HDI-trimer Desmodur N 3800 NCO : 11 % , viscosity @ 23°C : 6000 mPa·s
· HDI-/IPDI-polyisocyanate Desmodur NZ1 NCO : 23.5 % , viscosity @ 23°C : 700 mPa·s
· HDI-polyether-prepolymer Desmodur XP 2599 NCO : 6 % , viscosity @ 23°C : 2500 mPa·s
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 15
Still open questions
- How to make flexible films ?
Modification (100%)
Isocyanate modifications
% Elongation @ break
Standard
< 2%
HDI-oligomer
160 %
Symetric HDI-trimer
< 2%
Modified HDI-trimer
110 %
HDI-/IPDI-polyisocyanate
< 2%
HDI-polyether-prepolymer
100 %
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 16
Still open questions
- How to make flexible films ?
Isocyanate modifications
Modification with modified HDI-trimer
% Modification
% Elongation @ break
0
<2%
25%
5%
50%
10 %
75%
40 %
100%
110%
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 17
Still open questions
- How to make flexible films ?
Isocyanate modifications
Modification with modified HDI-polyether-prepolymer
% Modification
%Elongation @ break
25%
4%
50%
6%
75%
70 %
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 18
Still open questions
- How to make flexible films ?
Isocyanate modifications
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
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 19
Still open questions
- 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
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 20
Still open questions
- How to extend pot life ? · Oxazolidines
e.g. Hardener VP LS 2959 or Incozol 2 from Industrial Copolymers Ltd
· Molecular sieve powder 4Å
e.g. Sylosiv® A4 from W. R. Grace & Co
Pot life @ 23°C , min Standard
15 min
Oxazolidine , 0.75 % on formulation
23 min
Sylosiv A4 , 1.5 % on formulation
60 min
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 21
Still open questions
- How to increase chemical resistance ?
· Combination with other polyoles :
Not an option See page 10 – 13
≥ 1.5 Only suitable option right now Important Note : Existing patent for the USA
· Increase cross linking NCO : NH :
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 22
Still open questions
- 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® A4 from W. R. Grace & Co
· Degasing :
degasing of the comp. B (polyisocyanate) increases the max. DFT due to higher solubility of CO2 in the liquid coating material
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 23
Still open questions
- How to reduce viscosity ?
· Reactive diluents :
Aldimines / Ketimines e.g. Desmophen LS 2963A + VP LS 2142 limitation @ approx. 5% addition due to rapid 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 cases not an option
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 24
Still open questions
- How to reduce raw material costs ?
☺
That‘s something for the future far, far away ……
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 25
.2008-11 • Michael Casimir, Karl Wuehrer, Peg Kendi, page 26
