Claims
- 1. A method for forming an interpenetrated urethane linked coating composition on a substrate involving the steps of radiation and thermal curing by:
- (a) preparing a mixture containing:
- (1) from about 40 percent to about 90 percent by weight of a saturated polyol; and
- (2) from about 10 percent to about 60 percent by weight of a reactive diluent having a radiation sensitive pi bond and a boiling point greater than benzene and mixtures thereof; and
- (3) from about 80 percent to about 120 percent on a hydroxyl-isocyanate equivalent basis of a polyisocyanate;
- (b) applying the mixture to a substrate subjecting the coating so formed to sufficient radiation to polymerize the reactive diluent thereby partially curing the coating; and
- (c) then exposing the partially cured coating of (b) to sufficient thermal energy to form the urethane link,
- thereby forming the interpenetrated cured coating on the substrate.
- 2. The method of claim 1 wherein the sum of isocyanate functionality is greater than four.
- 3. The method of claim 2 wherein the saturated polyol is a hydroxy functional copolymer of (a) methyl methacrylate, (b) butyl acrylate, and (c) hydroxyethyl acrylate.
- 4. The method of claim 3 wherein the polyisocyanate is a di- or trifunctional isocyanate.
- 5. The method of claim 4 wherein the polyisocyanate is selected from the group consisting of:
- (a) toluene diisocyanate;
- (b) xylene diisocyanate;
- (c) isophorone diisocyanate;
- (d) hexamethylene diisocyanate;
- (e) the triisocyanate condensation product of hexamethylene diisocyanate and water;
- (f) trimethyl hexamethylene diisocyanate; and,
- (g) aliphatic diisocyanates having from 12 to 40 carbon atoms in the aliphatic moiety, and,
- mixtures thereof.
- 6. The method of claim 1 wherein the reactive diluent is 1,6-hexanediol diacrylate.
- 7. The method of claim 6 wherein the reactive diluent is a mixture of 1,6-hexanediol diacrylate and N-vinyl-2-pyrrolidone in a respective weight ratio of from about 4:1 to about 1:4.
- 8. The method of claim 7 wherein the radiation is ultraviolet.
- 9. The method of claim 8 wherein a free radical initiator is present.
- 10. The method of claim 8 wherein the thermal energy is applied at a temperature range of from about 0 degrees to about 300 degrees C.
- 11. The method of claim 7 wherein the radiation is electron beam.
- 12. The method of claim 1 wherein the reactive diluent is selected from the group consisting of:
- (a) 1,6-hexane diol diacrylate;
- (b) ethylene glycol diacrylate;
- (c) trimethylol propane triacrylate;
- (d) triethylene glycol diacrylate;
- (e) neopentyl diol diacrylate; and
- (f) pentaerythritol tetraacrylate,
- and mixtures thereof.
Parent Case Info
This is a continuation of application Ser. No. 945,370, filed Sept. 25, 1978, abandoned, which is a continuation of Ser. No. 759,311, filed Jan. 14, 1977, now U.S. Pat. No. 4,128,600.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1450288 |
Sep 1976 |
GBX |
Continuations (2)
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Number |
Date |
Country |
Parent |
945370 |
Sep 1978 |
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Parent |
759311 |
Jan 1977 |
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