Patent ID: 6884845

Claim:
A two-component, waterborne film-forming composition comprising: (A) a stable aqueous dispersion of a mixture of a polyester polyol and a carboxylic acid-containing acrylic polymer polyol as a first component, prepared by polymerizing a mixture of ethylenically unsaturated polymerizable monomers, in the absence of solvent, comprising: (1) at least one carboxylic acid group-containing monomer; (2) at least one primary alcohol group-containing monomer; (3) at least one glycidyl ester of an aliphatic saturated monocarboxylic acid; and (4) at least one polyester polyol, whereby the polymerization is carried out by feeding a mixture comprising (1), (2) and (4) to a reaction vessel over a period of time, wherein the equivalent ratio of the carboxylic acid groups from the carboxylic acid group-containing monomer to the epoxy group of the glycidyl ester of an aliphatic saturated monocarboxylic acid is greater than 1:1, and wherein the weight ratio of polyester polyol to acrylic polymer polyol is in the range of 10:90 to 30:70; and (B) a polyisocyanate crosslinking agent as a second component, wherein the equivalent ratio of hydroxyl groups in (A) to isocyanate functional groups in (B) is from 0.8:1 to 1.7:1.