Low temperature curable, two-component, waterborne film-forming composition

摘要

A waterborne film-forming composition is provided that includes a stable aqueous dispersion of a mixture of a polyester polyol and a carboxylic acid-containing acrylic polymer polyol having a weight ratio of polyester polyol to acrylic polymer polyol in the range of 10:90 to 30:70; and a polyisocyanate crosslinking agent where the equivalent ratio of hydroxyl groups to isocyanate groups is from 0.8:1 to 1.7:1. The polyol component is prepared by polymerizing a mixture of ethylenically unsaturated polymerizable monomers that includes at least one carboxylic acid group-containing monomer; at least one primary alcohol group-containing monomer; and at least one glycidyl ester of an aliphatic saturated monocarboxylic acid in the presence of at least one polyester polyol. Multi-layer composite coatings and coated substrates are also provided.