Basf Corporation

Timothy P Kandow

Gregory G Menovcik

Michael A Gessner

Herbert L Harmon

Robert Doty

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&deg; 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 0.05 to 0.8% according to a Gravel Chip Test.

Waterborne coating composition and a paint system thereof having improved chip resistance

The invention provides a thermosetting aqueous primer composition that includes a polyurethane polymer, an acrylic polymer, and a crosslinking component that is reactive with at least one of the polyurethane polymer and the acrylic polymer. The polyurethane polymer has a glass transition temperature of 0&deg; C. or less. The acrylic polymer has a glass transition temperature that is at least about 20&deg; C. higher than the glass transition temperature of polyurethane resin. The invention further provides a composite coating having as a primer layer a cured layer of the primer composition of the invention and having at least one topcoat layer.

Waterborne primer with improved chip resistance

The invention provides composite color-plus-clear coatings having improved appearance, especially with respect to wrinkling, and to methods and compositions for providing such coatings. The method of the invention utilizes a second coating composition comprising (A) a film forming component comprising (a) a first component comprising a compound having appended thereto at least one carbamate or urea functional group, or a group convertible to a carbamate or urea group, and (b) a second component comprising a compound reactive with said carbamate or urea groups on component (a), (B) a cyclic anhydride, and (C) a catalyst.

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Howell, MI, United States of America

Timothy P Kandow