Robert D Doty

US Patent:

6555231, Apr 29, 2003

Filed:

Jul 3, 2001

Appl. No.:

09/898320

Inventors:

Robert Doty - League City TX
Timothy P. Kandow - Howell MI

Assignee:

BASF Corporation - Southfield MI

International Classification:

B32B 2740

US Classification:

4284231, 4284233, 4284258, 524591

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 0Â 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.