Low temperature bake water reducible acrylic enamel

Claim 1

A water-reducible acrylic enamel coating composition comprising a substantially uniform mixture of a vehicle comprising a nonvolatile binder and a solvent, said binder comprising: (1) about 25% to about 40% of a water miscible partially etherified melamine formaldehyde resin containing from about 10% up to about 30% methylol groups, (2) about 60% to about 75% of an acrylic copolymer having a Tg of about -10° C. to about 45° C., a molecular weight of about 2,000 to about 100,000 and comprising the copolymerization product of: (a) about 3% to about 8% of an α, β unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid and mixtures thereof; (b) about 10% to about 30% of a hydroxy functional monomer selected from the group consisting of hydroxy C 2 to C 4 alkylacrylate, hydroxy C 2 to C 4 alkyl methacrylate and mixtures thereof, and (c) about 62% to about 87% of a nonfunctional monomer selected from the group consisting of acrylonitrile, styrene, C 1 to C 12 alkyl acrylates, C 1 to C 12 alkyl methacrylates and mixtures thereof, said acrylic copolymer further characterized as having the carboxyl group thereof substantially neutralized with a tertiary amine solubilizing agent to an extent sufficient to provide a pH of about 7 to about 12 and to impart hydrophilic properties to said copolymer, said solvent comprising a mixture of a water-miscible organic solvent and water, said coating composition characterized as capable of being substantially completely cured at a temperature of about 250° F.