COATING COMPOSITIONS CONTAINING POLYURETHANE DISPERSIONS ANDHIGHLY 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 produc t obtained by polymerizing a pre-emulsion formed from hydrophobic polymerizabl e 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 leas t 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 percen t by weight of prepolymers having at least one terminal ethylenic unsaturation at each end of the molecule.