Abstract: An acrylic-free, waterborne coating composition is disclosed. The waterborne coating composition produces a waterborne paint film having improved chip resistance on a substrate. The waterborne coating composition comprises an aqueous polyurethane dispersion substantially free from co-solvents. The polyurethane dispersion has a glass transition temperature from 0° C. or less and at least one carboxyl group. The waterborne coating composition also includes a melamine reactive with the carboxyl group. The aqueous polyurethane dispersion and the water-soluble cross-linker form a binder component of the waterborne coating composition. The binder component includes from 60 to 90% by weight of the aqueous polyurethane dispersion based on 100% by weight of the binder component and from 10 to 40% by weight of the water-soluble cross-linker based on 100% by weight of the binder component. The waterborne coating composition is applied having a film build of 0.5 to 5.0 mils and produces a paint film loss of from 0.
Abstract: The present invention is directed to a curable, water-based coating composition utilized in waterborne coating systems. The coating composition is the reaction product of a water-based copolymer prepared by free-radical polymerization, and a cross-linking agent. The copolymer is the reaction product of a first block and a second block. The first block is the reaction product of a first ethylenically unsaturated monomer, acrylic acid, and a second ethylenically unsaturated monomer, methyl methacrylate, as wells as the reaction product of a vinylaromatic hydrocarbon monomer, diphenylethylene. The second block is the reaction product of a plurality of ethylenically unsaturated monomers, styrene, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and carbonate-modified glycidyl methacrylate including a carbonate functional group.
Type:
Grant
Filed:
December 22, 2000
Date of Patent:
June 11, 2002
Assignee:
BASF Corporation
Inventors:
Swaminathan Ramesh, Paul Lessek, Wolfgang Bremser