Crosslinkable compositions containing polyepoxides and polyacid curing agents
AssigneePPG Industries, Inc.
InventorsWilliam P. Blackburn, Debra L. Singer
Life of this patent
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Abstract
Curable, liquid coating compositions based on polyepoxides and polyacid curing agents are disclosed. The compositions also contain volatile components such as solvent or curing agents which release volatile components upon curing. Also present is a relatively long chain aliphatic monocarboxylic acid which is present to improve the appearance of the coatings. The compositions are useful as coating compositions particularly as clear coats in color-plus-clear automotive coatings.
Claims26
A curable, liquid coating composition containing components which volatilize at or release volatiles at curing temperature comprising:
- (A) 30 to 60 percent by weight of a polyepoxide,
- (B) 20 to 50 percent by weight of a polyacid crosslinking agent, and
- (C) 0.1 to 15 percent by weight of a monocarboxylic acid containing at least 6 carbon atoms;
- the percentage by weight based on weight of resin solids and the equivalent ratio of (A) to (B)+(C) is 0.75-1.5 to 1 and the equivalent ratio of (B) to (C) is 5-20 to 1.
A curable, liquid coating composition containing components which volatilize at curing temperature comprising:
- (A) 30 to 60 percent by weight of a polyepoxide including:
- (i) a copolymer of a monoethylenically unsaturated monomer having at least one epoxy group and at least one monoethylenically unsaturated monomer which is free of epoxy groups and the copolymer has a number average molecular weight of 1000 to 20,000,
- (ii) 5 to 30 percent by weight of a polyepoxide having a molecular weight of less than 800,
- (B) 20 to 50 percent by weight of a carboxyl-terminated polyester curing agent which is a half-ester of the structure:
- ##STR3## where X is the residue of a polyol after reaction with a 1,2-dicarboxylic acid anhydride, R is an organic moiety associated with the anhydride, and A is equal to at least 2,
- (C) 1 to 30 percent by weight of an aminoplast, and
- (D) 0.1 to 15 percent by weight based on weight of resin solids of a monocarboxylic acid containing from 8 to 22 carbon atoms;
- the percentage by weight based on weight of resin solids;
- the equivalent ratio of (A) to (B)+(D) is 0.75-1.5 to 1 and the equivalent ratio of (B) to (D) is 5-20 to 1.
Dependencies are inferred from the claim text.