Donald C Hart

US Patent:

44698410, Sep 4, 1984

Filed:

Mar 4, 1983

Appl. No.:

6/472235

Inventors:

Donald J. Hart - Sterling Heights MI
Robert A. Ottaviani - Washington MI

Assignee:

General Motors Corporation - Detroit MI

International Classification:

C08K 543
C08L 3314

US Classification:

524512

Abstract:

Waterborne acrylic copolymer-melamine enamels have a long storage life at room temperature and yet are curable at relatively low temperatures when containing suitable sulfamate ester curing agents such as ethyl N,N-dimethylsulfamate.

US Patent:

45407347, Sep 10, 1985

Filed:

Jul 30, 1984

Appl. No.:

6/635555

Inventors:

William T. Short - Southfield MI
Robert A. Ottaviani - Washington MI
Donald J. Hart - Sterling Heights MI

Assignee:

General Motors Corporation - Detroit MI

International Classification:

C08L 7500

US Classification:

524507

Abstract:

Novel, high solids urethane clearcoat compositions having improved flow characteristics by the incorporation of a flow control system composed of urea thixotrope/acrylic microgel additives. The urea thixotrope constituent is prepared by reacting a polyether polyol with a stoichiometric excess of a saturated cyclic aliphatic polyisocyanate to produce isocyanate-terminated prepolymers. These prepolymers are then modified by reaction with an ethanolamine to form urea end-capped thixotropes which are compatible in structure with any urethane clearcoat system. A combination of one of these urea thixotropes and a polymethyl methacrylate microgel of fine particle size is used effectively to reduce sagging of high solids urethane clearcoat systems. In fact, the combination of the two components produces a synergistic effect which is greater than that expected from any one of the components in the flow control system.

US Patent:

45283192, Jul 9, 1985

Filed:

Jul 20, 1984

Appl. No.:

6/633055

Inventors:

Robert A. Ottaviani - Washington MI
William T. Short - Southfield MI
Donald J. Hart - Sterling Heights MI

Assignee:

General Motors Corporation - Detroit MI

International Classification:

C08K 336

US Classification:

524540

Abstract:

Novel, high solids urethane clearcoat compositions having improved flow characteristics by the incorporation of a flow control system composed of urea thixotrope/silica additives. The urea thixotrope constituent is prepared by reacting a polyether polyol with a stoichiometric excess of a saturated cyclic aliphatic polyisocyanate to produce isocyanate-terminated prepolymers. These prepolymers are then modified by reaction with an ethanolamine to form urea endcapped thixotropes which are compatible in structure with any urethane clearcoat system. A combination of one of these urea thixotropes and a finely divided transparent silica is used effectively to reduce sagging of high solids urethane clearcoat systems. In fact, the combination of the two components produces a synergistic effect which is greater than that expected from any one of the components in the flow control system.