REAXIS C333 Water Soluble Catalyst Evaluation in Two-Component Waterborne Polyurethane Coatings

Transcription

1 REAXIS C333 Water Soluble Catalyst Evaluation in Two-Component Waterborne Polyurethane Coatings Presented by: Martin Rickwood Authors: Lanny Venham Leon Perez Michael Curcione

2 Overview Evaluation of new water soluble catalyst o Two component waterborne polyurethanes o Urethane/polyester polyol and polyester polyol o Water dispersible HDI based polyisocyanate Comparison to commercially available catalysts o Determination of standard properties Coating dry times and hardness Shelf life and pot life Solvent resistance Effect of humidity on drying Selectivity

3 Background Drivers for development of 2K WB PU coatings o Compliance with VOC regulations o Decrease worker exposure hazards 2K WB PU coatings deficiencies o Poor drying speed under humid conditions o Inferior appearance vs. solvent based technology o Diminished film performance properties

4 Cured Waterborne Polyurethane Films (with and without REAXIS C333 catalyst) 0.6 Green REAXIS C333 catalyst 0.4 Blue no catalyst Abs Wavenumber [cm-1]

5 Formulation 1 Urethane Modified Polyester Polyol with HDI Trimer Raw Material Weight Volume Weight Solids Volume Solids Bayhydrol Byk Byk Ammonia (10% in DI water) Catalyst (100%) Water Letdown Bayhydur Total Weight % Solids Weight/gallon 9.15 Volume % Solids NCO:OH 2.00

6 Formulation 2 Standard Polyester Polyol with HDI Trimer Raw Material Weight Volume Weight Solids Volume Solids US Polymers W2K Byk Byk Ammonia (10% in DI water) Catalyst (100%) Water Letdown Bayhydur Total Weight % Solids Weight/gallon 8.96 Volume % Solids NCO:OH 2.00

7 Formulation 1: Physical Properties F/50%RH) System Set-to a Dust free b Dry hard c MEK DR d Pencil e No cat H REAXIS C H DBTDL H Sn Octoate H Bi Octoate pass 2H Zn Complex H Zr Complex H a Set-to: Time in minutes set to touch with cotton ball non-sticking b Dust free: Time in minutes that cotton ball hairs do not adhere to the coating c Dry hard: Time in minutes that coating achieves cure with no stickiness d MEK DR: pass = 50 MEK double rubs without breaking through the film e Pencil Hardness: Run after 7 days curing at room temperature

8 Formulation 2: Physical Properties F/50%RH) System Set-to Dust free Dry hard MEK DR Pencil No cat H REAXIS C H DBTDL B Sn Octoate H Bi Octoate pass H/F Zn Complex H Zr Complex H

9 Shelf Life - Aged at 60 C (catalyst in A side, polyol) System Set-to Dust free Dry hard MEK DR Pencil Time REAXIS C H 2 weeks REAXIS C H 4 weeks REAXIS C H 6 weeks Used Formulation 3 on next slide

10 Formulation 3 Urethane Modified Polyester Polyol with HDI Trimer Raw Material Weight Volume Weight Solids Volume Solids Bayhydrol Dynol 604 surfactant Surfynol DF-58 defoamer Catalyst (100%) Byk Water Letdown Ektapro EEP Bayhydur Total Weight % Solids Weight/gallon 9.14 Volume % Solids NCO:OH 2.00 P/B Ratio Mix ratio 3.49

11 Formulation 1: Pot Life Comparisons Physical Properties Before/After Aging 2 Hours cured (@77 F/50%RH) System Set-to Dust free Dry hard MEK DR Pencil No catalyst 140/90 220/ /275 / 3H/3H REAXIS C333 75/45 140/85 185/145 / 3H/3H DBTDL 85/55 130/ /190 / 2H/2H Sn Octoate 95/65 150/ /210 / 2H/2H Bi Octoate 90/65 170/ /185 / 2H/H Zn Complex 95/70 145/ /175 / 3H/3H Zr Complex 110/75 150/ /185 / 3H/2H

12 Formulation 2: Pot Life Comparisons Physical Properties Before/After Aging 2 Hours cured (@77 F/50%RH) System Set-to Dust free Dry hard MEK DR Pencil No cat 250/ / /420 / H/H REAXIS C333 75/55 135/ /150 / H/2H DBTDL 95/60 160/ /185 / B/HB Sn Octoate 110/85 140/ /190 / H/H Bi Octoate 155/ / /240 / (H-F)/F Zn Complex 130/ / /185 / H/H Zr Complex 135/ / /260 / H/(H-F)

13 Formulation 1: Physical Properties at Variable Humidity Cure Conditions Set-to Dust free Dry hard MEK DR Pencil Hardness 50% RH, 77 F H 75% RH, 77 F H 90% RH, 77 F H

14 Selectivity of REAXIS C333 for NCO/OH Reaction Relative Rate of NCO/OH vs. NCO/Water - Ln (NCO abs.) vs. Time REAXIS C333 1-BuOH REAXIS C333 Water -Ln Abs. at 2270 cm Time (min)

15 Summary & Conclusions REAXIS C333 Advantages Water soluble Also soluble in organic media Hydrolytically stable o Provides good storage stability Good selectivity in promoting NCO reaction o Reaction with OH is 6 times faster than water Wide application latitude o Cures well under high humidity conditions

16 Curing of 2K WB coating, NCO loss No Catalyst Water Soluble Tin Water Soluble Zinc REAXIS C333 Emulsified DBTDL Ratio 2270 / 2935 cm Days

17 References 1. Gaal, R. and Jackson, M. A. A Cost-Effective, Water-Reducible Polyester Polyol for Two-Component Waterborne Urethane Coatings, PCI Magazine, January 1, Williams, J High Solids Polyurethane Coatings: Past, Present, and Future, presented at the Water-Borne, Higher Solids, and Powder Coatings Symposium, February 24-26, Jacobs, P. B. and Yu, P. C Two-Component Waterborne Polyurethane Coatings, presented at the Water-Borne, Higher Solids, and Powder Coatings Symposium, February 26-28, Seneker, S. D. and Potter, T. A., Solvent and Catalyst Effects in the Reaction of Aliphatic Isocyanates with Alcohols and Water, J. Coatings Tech., 63(713):19.

18 NCO and Water Concentrations in a W/B Curing Film NCO and Water profile 0.25 NCO, 2265 cm-1 Water, 3320 cm Abs Time (min)

19 Polyisocyanate and Polyol Micellar Structures Polyisocyanate micelle Polyol micelle with typical catalysts

20 Formulation 3: Effect of NCO/OH Ratio US Poly W2K2000/ Bayhydur 302 Physical Properties, cured F/50%RH) NCO/OH Ratio Set-to a Dust free b Dry hard c MEK DR d Pencil e F F/H H

21 Formulation 3: Effect of NCO/OH Ratio Bayhydrol XP-2591/ Bayhydur 302 Physical Properties, cured F/50%RH) NCO/OH Ratio Set-to a Dust free b Dry hard c MEK DR d Pencil e F/H H >100 3H

22 Relative Rate for Catalysis of NCO/Water Reaction -Ln (Abs.) at 2270 cm Ln (NCO abs.) vs. Time C333 Water DBTDL water Time (min)