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.
