Claims
- 1. A process for applying a composite coating to a substrate which comprises applying to the substrate a colored film-forming composition to form a base coat and applying to said base coat a clear film-forming composition to form a transparent top coat over the base coat, characterized in that the clear film-forming composition is a crosslinkable composition comprising a polyepoxide and a polyacid curing agent, wherein the polyepoxide is a polyepoxide-containing polymer which contains one or more pendant groups of the structure: ##STR20## where X is ##STR21## or --O and R is H or alkyl of 1-18 carbon atoms or R is bonded to X and forms part of a five- or six-membered ring and R' is alkyl of 1-18 carbon atoms.
- 2. The process of claim 1 where R is H or alkyl of 1-6 carbon atoms or R is bonded to X and forms part of a 5 or 6 membered ring and R' is alkyl of 1-6 carbon atoms.
- 3. The process of claim 2 in which X is --O and R is selected from the group consisting of H and alkyl having 1-6 carbon atoms.
- 4. The process of claim 2 in which X is ##STR22## R is bonded to X and is --CH.sub.2 --CH.sub.2.
- 5. The process of claim 1 in which the polyepoxide-containing polymer is an epoxy group-containing acrylic polymer.
- 6. The process of claim 5, in which the epoxy group-containing acrylic polymer is a copolymer of glycidyl acrylate or glycidyl methacrylate with at least one other copolymerizable ethylenically unsaturated monomer.
- 7. The process of claim 1 in which the polyepoxide-containing polymer has an equivalent weight of from about 5000 to 100,000 based on equivalents of pendant groups. polymer.
- 8. The process of claim 1, wherein the polyacid curing agent is selected from the group consisting of a carboxylic acid group-containing oligomer and polymer.
- 9. A substrate coated by the process of claim 1.
- 10. The process of claim 8, in which for each equivalent of carboxyl there are 0.8 to 1.5 equivalents of epoxy.
- 11. The process of claim 1, wherein the polyacid curing agent is selected from the group consisting of a carboxylic acid group-containing oligomer and polymer having the acid groups and wherein the polyacid curing agent is reactive in a range of equivalents with the polyepoxide that has said pendant groups so that for each equivalent of carboxyl there is 0.3 to 3.0 equivalent of epoxy to form a crosslinked coating.
Parent Case Info
This is a division of application Ser. No. 08/047,904, filed Apr. 19, 1993, now U.S. Pat. No. 5,384,367.
US Referenced Citations (26)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0485990A2 |
May 1992 |
EPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
47904 |
Apr 1993 |
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