1. Next Generation Polyester Dispersion for 2K Waterborne Urethane Coatings
Michael Knight
Polynt Composites USA Inc.
Technical Service Manager
October 26-28, 2015

2. Agenda Background Polyester development
2K waterborne polyester dispersion
Outgassing
Chemical resistance
Salt spray resistance
Conclusion

3. Background Waterborne 2K urethane coatings since 1980’s
As VOC regulations tightened, waterborne 2K more prevalent
Flooring, kitchen cabinets, golf balls
Advances in water dispersible isocyanates and waterborne polyols
DTM and corrosion has not been addressed
Advancements have been made with a polyester dispersion over B-1000 treated steel

4. Polyester Development - Background
Development of BPA-NI can coatings
BPA under scrutiny by FDA and European regulatory agencies
Biggest hurdle for polyester was retort
Foods sterilized in can with superheated steam under pressure – 90 minutes at 250 F
Mimic epoxy high Tg and formability
Highly hydrophobic polyester
High Tg
High molecular weight
Low hydroxyl for minimal crosslinking

5. 2K Waterborne Polyester - Development
Apply same approach, use same basic polyester backbone
Increase hydroxyl number from 30 to 150
Reactivity with isocyanate
Resultant lower Mw
Maintain hydrophobic, cyclic backbone
Maintain water resistance
Tightly internal crosslink density
Highly branched

6. 2K Waterborne Urethane Formulation
Critical parameters
1.5 eq. NCO/1.0 eq. OH
Type of isocyanate
Side reaction with water
CO2 outgassing
Critical physical tests
Hardness development
Adhesion to CRS and aluminum
Chemical resistance
Corrosion resistance
B-1000
240 hrs. salt spray, scrape scribe

7. Outgassing
Commercial
Experimental

8. Hardness and Adhesion Tested with three different isocyanates:
Polynt Resin
NCO
NCO Eq.
FB (mils)
72 Hrs. Konig (sec)
Crosshatch Adhesion
(CRS / AL)
Commercial
Easaqua XL 600a
1.5
1.51 66
4 / 2
Experimental
Easaqua XL 600
153
5 / 5
Bayhydur XP-2655b 56
0 / 0
Bayhydur XP-2655
1.54
163
Bayhydur 302
1.52 39 92
aPerstorp, bBayer

9. Chemical Resistance Tested with three different isocyanates:
Polynt Resin
NCO
Fantastik
Formula 409
Bleach
Brake Fluid
1:1 Antifreeze
10% HCL
10%
NaOH
Commercial
Easaqua XL 600 5 1 8 7
Experimental 10
Bayhydur XP-2655 3
Bayhydur 302
10 = Best
0 = Worst

10. Corrosion Resistance
Isocyanates tested expanded to 11 different isocyanates or blends
Bayhydur 302
Bayhydur XP-2547
Bayhydur XP-2655
Bayhydur XP-2487/1
Bayhydur XP-2655 / (75 / 25)
Bayhydur XP-2547 / XP-2655 (75 / 25)
Bayhydur XP-2547 / XP-2655 (50 / 50)
Bayhydur XP-2547 / XP-2655 (25 / 75)
Easaqua XL-600
Easaqua XD-803 (HDI / IPDI blend)
Easaqua XM-501 (most hydrophobic)

11. Corrosion Resistance Salt Spray Results - 240 Hours Formula #
Description
Substrate
Field
Scribe Blister
Blister
Corrosion H
Commercial/Bayhydur 302
B-1000
9vd 10
9vd8m A
Experimental/Bayhydur 302
9m-8f 9g
9d8md B
Experimental/Bayhydur XP-2655
9d7vf
Rating Key:
Blisters 0-10 with 0 being largest size blister:
F = few blisters
M = medium amount of blisters
MD = medium dense blisters
D = dense blisters
VD = very dense
Creepage (corrosion extending from scribe mark):
10 = no creepage
9 = up to 0.5 mm
8 = up to 1.0 mm
7 = up to 2.0 mm
6 = up to 3.0 mm
5 = up to 5.0 mm
4 = up to 7.0 mm
3 = up to 10.0 mm
2 = up to 13.0 mm
1 = up to 16.0 mm
0 = over 16.0 mm
Corrosion 0-10 with 0 being 100% corrosion:
P = pinpoint corrosion
S = spot corrosion
G = general corrosion
“>” = not quite as bad as the value given, but not as good as the value one higher than the value given
“<” = not quite as good as the value given, but not as bad as the value one lower than the value given
Creepage reported as Average, Maximum, and % of creep to the maximum degree

12. Corrosion Resistance
Salt Spray Results – 240 Hours on B (scribe scraped with spatula)
Before Scraping
Commercial with 1.5 Eq. Bayhydur 302
Before Scraping
Experimental with 1.5 Eq. Bayhydur 302

13. Corrosion Resistance
Salt Spray Results – 240 Hours on B (scribe scraped with spatula)
Experimental with 1.5 Eq. Bayhydur XP-2655
Before Scraping

14. 2K Waterborne Formulation
The experimental polyester dispersion can be formulated to less than 50 g/L without the use of plasticizers or coalescing additives. This high gloss formula provides excellent adhesion to steel.
High Gloss White 2K System with Experimental Polyester Dispersion
Ingredients
Function
Pounds
Gallons
Component A:      
Grind:
Distilled Water
Diluent
70.91
8.51
Disperbyk 190a
Dispersant
6.05
0.68
BYK-1710a
Defoamer
1.28
0.26
Ti-Pure R-902b
Pigment
267.06
8.02
Grind with glass beads to a 7 Hegman
Letdown:
Experimental Polyester Dispersionc
Binder
556.94
62.86
BYK-346a
Surfactant
2.63
0.31
BYK-3455a
1.32
0.15
15% NaNO3
Flash rust inhibitor
2.49
0.29
Component B:      
Bayhydur XP-2655d
141.49
14.65
35.57
4.27
Mix components A & B for minutes with mechanical mixing
Total Formulation 
100.00
Formulation Constants
Paint Properties
Nonvolatile by weight (%)
54.0
Gloss - 20°
87.8
Nonvolatile by volume (%)
44.01
93.4
Weight per gallon (lbs/gal)
10.85
11.5
Pigment to binder ratio
0.83
PVC (%)
21.62
Calculated VOC (lbs/gal)
0.02
Calculated VOC (g/L)
2.35
1.5 eq NCO/1.0 eq OH

15. Other Approaches to Improve Salt Spray Results
Modify polyester with hydrophobic, cyclic polyols or anhydrides
Tricyclodecane dimethanol
Nadic anhydride
Trimellitic anyhdride
Terephthalic anhydride
Others
High Tg phenoxy
Carbonate diols
Silane coupling agents

16. Summary Two to three times harder Improved adhesion to CRS and AL
Improved chemical resistance
Improved corrosion resistance on B-1000
Next generation polyester dispersion for 2K waterborne urethane coatings should be commercial by Q2 2015
Any questions …