COATING COMPOSITIONS CONTAINING POLYURETHANE DISPERSIONS AND HIGHLY CROSSLINKED POLYMER PARTICLES

摘要

An aqueous polyurethane dispersion and thermosetting compositions containing them. The aqueous polyurethane dispersion includes an aqueous medium with dispersed polyurethane-acrylate particles, which include the reaction product obtained by polymerizing a pre-emulsion formed from hydrophobic polymerizable ethylenically unsaturated monomers, a crosslinking monomer, and an active hydrogen-containing polyurethane acrylate prepolymer, which is a reaction product obtained by reacting a polyol, a polymerizable, ethylenically unsaturated monomer containing at least one hydroxyl group, a compound that includes an alkyl group having at least one hydroxyl group and optionally a carboxylic acid group, and a polyisocyanate. The prepolymer includes at least 30 percent by weight of polyurethane acrylate prepolymers with at least one terminal ethylenic unsaturation at one end of the molecule, and at least one active hydrogen-containing group at the opposite end; and at least 10 percent by weight of prepolymers having at least one terminal ethylenic unsaturation at each end of the molecule.