Claims
- 1. A curable film-forming composition comprising (i) pigment; (ii) an aminoplast crosslinking agent containing methylol and/or methylol ether groups, present in the film-forming composition in amounts of about 25 to 50 percent by weight based on the total weight of resin solids in the film-forming composition; and (iii) a mixture of (a) an acrylic polymer or oligomer containing a plurality of groups of the structure: ##STR8## wherein R.sub.1 is hydrogen or methyl and R.sub.2 is a divalent linking group; and (b) a polyester polymer or oligomer containing a plurality of terminal carbamate groups of the structure: ##STR9## wherein said mixture is present in the film-forming composition in amounts of about 20 to 75 percent by weight based on the total weight of resin solids in the film-forming composition; and wherein the pigment to binder ratio of the film-forming composition is about 0.01 to 1.5 and the film-forming composition is suitable for application over a substrate as a monocoat.
- 2. The film-forming composition of claim 1 wherein prior to crosslinking the film-forming composition has a theoretical hydroxyl value less than 50 based on the total solid weight of the film-forming composition, excluding any hydroxyl functionality associated with N-methylol groups.
- 3. The film-forming composition of claim 1 wherein the acrylic polymer or oligomer is present in the film-forming composition in amounts of about 20 to 65 percent by weight based on the total weight of resin solids in the film-forming composition.
- 4. The film-forming composition of claim 3 wherein the acrylic polymer or oligomer has an equivalent weight of from about 140 to 800 based on equivalents of carbamate groups.
- 5. The film-forming composition of claim 3 wherein R.sub.2 has from about 2 to 20 carbon atoms.
- 6. The film-forming composition of claim 5 wherein R.sub.2 has the structure: ##STR10##
- 7. The film-forming composition of claim 5 wherein R.sub.2 has the structure:
- 8. The film-forming composition of claim 1 wherein the polyester polymer or oligomer is present in the film-forming composition in amounts of about 20 to 65 percent by weight based on the total weight of resin solids in the film-forming composition.
- 9. The film-forming composition of claim 1 wherein the aminoplast is present in the film-forming composition in amounts of about 30 to 45 percent based on the total weight of resin solids in the film-forming composition.
- 10. The film-forming composition of claim 1 wherein said aminoplast is a condensate of melamine with formaldehyde and optionally an alcohol containing from 1 to 4 carbon atoms.
- 11. The film-forming composition of claim 1 wherein the equivalent ratio of carbamate groups to methylol or methylol ether groups is from about 0.5 to 2:1 and is sufficient to form a crosslinked film.
- 12. The film-forming composition of claim 1 present as a monocoat on electrocoated substrate.
- 13. The film-forming composition of claim 12 which is present from an application of two coats with a flash time period between the application of the each coat.
- 14. The film-forming composition of claim 1 wherein both the acrylic and polyester polymer or oligomer are present in an amount in the range of about 20 to 75 percent by weight.
- 15. The film-forming composition of claim 14 wherein the acrylic and polyester polymer or oligomer are present in a ratio of 40 to 60.
Parent Case Info
This application claims the benefit of U.S. Provisional Application No. 60/025,448, filed Sep. 4, 1996.
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