1. Low VOC High Performance 1K Waterborne Polyurethanes
For Wood Coatings
Kevin Quinn Pacific Northwest Society for Coating Technology
October 9, 2014

2. Definitions: PUD = Polyurethane dispersion (waterborne)
1K = 1 component coating PUD
1K PUD LZ-1 = 1K low VOC (<140g/L) self-crosslinking (at R.T.) PUD
2K = 2 component coating (polymer + crosslinker)
2K NCO = 2K commercial PUD coating with polyisocyanate crosslinker
2K Aziridine = 2K commercial PUD coating with polyaziridine crosslinker

3. Outline Introduction and background of topic
Factors affecting PUD performance and VOC’s
Process
Polyurethane structural characteristics
Morphology
Raw materials/composition
Crosslinking
Comparison of 1K and 2K PUD attributes and performance
Summary

4. Introduction and Background
- Thermoplastic Waterborne Finishes for Wood Flooring
Inadequate mar and black heel mark resistance
Poor alcohol/ polar solvent resistance
- 2K Waterborne Finishes for Wood Flooring
Commercial approach typically using polyaziridines or polyisocyanates as crosslinking components with polyurethane dispersions
Excellent chemical, mar and black heel mark resistance
- Many Performance grade Floor Finishes for Wood Flooring are typically high VOC
Solventborne Polyurethanes
Waterborne Polyurethane at >270 g/L and may contain NMP as cosolvent.
Target = Low VOC High Performance 1K PUD Resins that offer properties required for wood flooring applications & improved user friendliness

5. Introduction and Background
Generation I = Soft 1K PUD containing NMP Generation II = Soft 1K PUD without NMP Generation III = Harder 1K PUD containing NMP Generation IV = Harder 1K PUD without NMP and capable of formulations at <140 g/L VOC coatings.

6. Factors Affecting PUD Coating VOC’s & Performance
Synthetic process
Polyurethane structural characteristics
Particle morphology
Raw materials/composition
Crosslinking

7. PUD Prepolymer Process
Water Dispersing Group OH HO
NCO
OCN + x
Poly-isocyanate
Polyol z
NH2
H2N
COOH
1) Neutralize
2) Water
Waterborne Polyurethane Dispersion
+ Diluent
Process Aid
(viscosity control)
Urethane Formation
Urea Formation

8. Polyurethane Block Copolymer Structure and Phase Separation{
Diisocyanate
Chain extender or
Diol
Soft segment (SS)
Hard segment (HS)
urethane block

9. Raw Material Options for Balanced Performance
Polyisocyanate: aromatic, aliphatic, functionality
Polyol: polyesters, polyethers, polycarbonates
Diols (hard segment modifiers): butane diol, cyclohexyl dimethylol, etc.
Crosslinking Functionality: acetoacetonate, carbonyl, unsaturation (other options with applied energy)

10. Diisocyanates (Hard Segment)
Type Advantages
Aromatic
TDI - Toluene Diisocyanate Hardness &
MDI - Diphenylmethane Diisocyanate Low Cost
Aliphatics
HDI - Hexamethylene Diisocyanate Flexibility &
TMXDI - Tetramethyl Xylene Diisocyanate Light Stability
IPDI - Isophorone Diisocyanate
H12MDI - Hydrogenated Diphenylmethane Diisocyanate

11. Polyols (Soft Segment)
Type Advantages Disadvantages
Polyethers Softness Adhesion to plastics
(excluding PEO) Flexibility Weatherability (oxidizable)
Hydrolytic Stability Poor solvent resistance Solvent Resistance- (PPG’s)
(PTMEG)
Low Cost (PPG’s)
Polyesters Adhesion Hydrolytic Stability
Toughness
Abrasion Resistance
Exterior Durability
Synthetic Flexibility
Polycarbonates Hydrolytic Stability Cost
Weatherability Availability

12. 1K and 2K Ambient Crosslinked Coatings
-Helpful for obtaining required performance while maintaining low VOCs
2K Crosslinked Polymer:
Applicator mixes (1) crosslinker + (2) polymer base on the job: requires proper measurement and mixing, potential exposure
Chemical reaction typically starts when crosslinker is added
Mixture needs to be used before pot life expires
1K Self-Crosslinking Polymer:
Crosslinking mechanism is built into the polymer
Chemical crosslink reaction is activated as finish dries
For on-site floor finishes this is at low or ambient temperatures (4˚-32˚C)

13. Chemical Resistance Test 1K PUD LZ-1 (140g/L) (50g/L) 2K Aziridine
2K NCO
(275 g/L)
Water (16 hr) 5
1.4% Ammonia (1 hr) 4 3
1% Spic and Span (4h)
Red Wine (6 hr)
Mustard (6 hr)
MEK (1 hr)
50% Ethanol (1 hr)
IPA (1 hr)
MEK Double Rubs (100)
Ethanol Double Rubs (100)
Overall Total 47 43 48 44

14. Solvent Swells (Degree of Crosslinking)
Cure Time at RT- Solvent
1K PUD LZ-1
without crosslink
(140 g/L)
(% Increase)
with crosslink
2K Aziridine PUD
(275g/L)
2K NCO
PUD
(% Increase )
1 Day RT Cure
MEK
108 28 18
24 (slight white)
IPA 36 16 11
14 (slight white)
NMP
dissolved 52 46 62
7 Day RT Cure
100 17
12 (slight white) 50 42

15. DMA Comparison of 1K and 2K PUDs

16. Black Heel Mark (Scuff) Resistance

17. Black Heel Mark Appearance on Wood
non-crosslinked PUD
(275g/L)
2K NCO Crosslinked
1K LZ-1 PUD
(140g/L)
2K Aziridine Crosslinked

18. Wear/Abrasion Resistance10 20 30 40 50 60 70 80
900
100
High VOC 1K PUD
(with NMP)
<140g/L
1K PUD
2K PUD
( Aziridine)
Milligrams Wt. Loss/1000 Cycles
Low Value
Average
High Value
(NCO)
Taber Abrasion

19. Adhesion: Solventborne Wood Stain
Solventborne Stained Wood Panel
1K PUD LZ-1
Top Coat
Competitive PUD
Top Coat

20. Summary: Low VOC High Performance 1K Waterborne Polyurethanes
Engineered for low VOC NMP-free formulation as a 1K wood floor finish comparable to two component PUD performance.
No additional crosslinker required – no pot-life issues, no mixing issues, no handling issues, reduced waste and disposal cost
Target: NMP free, <140g/L, 2K performance
Easy to apply, user friendly, quick dry – multiple coats per day
Polymer crosslinks upon application as it dries – as a result coating produced have:
Rapid hardness development and abrasion resistance
Cleaners- and alcohol- resistance on-par with 2K WB systems
Comparable sport floor wear to commercial 2K crosslinked PUDs
Excellent Adhesion to solventborne stains

21. Thank You For Attending
and To The People Who Helped Make it Happen:
Anthony Pajerski
George Ahrens
Jonathan Bird
Svetlana Lerner
Diawn Jones
Tony Kropinak
Matt Haney
Lisa Blevins
Charles Nelson
Naser Pourahmady
Bob Samelson
Vic Stanislawczyk

22. Disclaimer
Trademarks owned by The Lubrizol Corporation © The Lubrizol Corporation 2014, All Rights Reserved, February 2014