Patent No. U.S. 6,555,231 B2
BASF Corp. has received a patent for an acrylic-free, waterborne coating composition for producing a waterborne paint film having improved chip resistance on a substrate. The waterborne coating composition is comprised of an aqueous polyurethane dispersion, having a glass transition temperature from 0° C. or less, substantially free from co-solvents and having at least one carboxyl group, a water-soluble cross-linker reactive with the carboxyl groups. The aqueous polyurethane dispersion and the water-soluble cross-linker form a binder component of the waterborne coating composition, the binder component is comprised of 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.