Thermosetting powder coating composition of an acrylic polymer, dodecanedioic acid, cellulose acetate butyrate and a cross-linking agent
AssigneeE. I. Du Pont de Nemours and Company
InventorClaus Victorius
Life of this patent
Estimating the term…
Abstract
A thermosetting polymer powder coating composition comprising finely divided powder particles that have a diameter of about 1-100 microns wherein the powder particles are a blend of A. an acrylic polymer of glycidyl methacrylate, an alkyl methacrylate or an alkyl acrylate having 1-12 carbon atoms in the alkyl groups, B. dodecanedioic acid, C. low viscosity cellulose acetate butyrate, D. an alkylated melamine formaldehyde crosslinking agent, and E. a blocked acid catalyst; The powder coating composition is particularly useful as an exterior finish for automobile and truck bodies.
Claims11
A thermosetting polymer powder coating composition comprising finely divided particles having a particle size of about 1-100 microns;
- wherein the particles are an intimately mixed blend of constituents consisting essentially of about
- (A) 55-85% by weight of an acrylic polymer consisting essentially of
- (1) about 5-25% by weight, based on the weight of the acrylic polymer, of glycidyl methacrylate or glycidyl acrylate,
- (2) about 75-95% by weight, based on the weight of the acrylic polymer, of an alkyl methacrylate or an alkyl acrylate each having 1-12 carbon atoms in the alkyl groups or a mixture of said alkyl methacrylate and said alkyl acrylate;
- and
- wherein the acrylic polymer has a weight average molecular weight of 5,000-15,000, and a glass transition temperature of 50.degree.-98.degree. C.;
- (b) 5-15% by weight of dodecanedioic acid;
- (C) 5-20% by weight of cellulose acetate butyrate having a viscosity of about 0.005-1.0 seconds measured according to ASTM-D-134356 at 25.degree. C. and a butyryl content of about 25-60%;
- (D) 2-8% by weight of an alkylated melamine formaldehyde cross-linking agent having 1-4 carbon atoms in the alkyl group;
- and
- (E) 0.1-2.0% by weight of a blocked acid catalyst wherein the molar ratio of carboxyl groups of the dodecanedioic acid to epoxy groups of the acrylic polymer is about 0.8-1.5.
Dependencies are inferred from the claim text.