Novel cross-linking agents and their use in electrophoretic coating composition

Claim 1

In an electrophoretic coating composition comprising, in aqueous dispersion, a mixture of from about 5% to about 40%, by weight, of (A) an aminoplast condensation product and, correspondingly, from about 95% to about 60%, by weight, of (B) a water-dispersible, non-gelled, polymeric material carrying an ionic charge, which polymeric material contains at least one class of reactive groups selected from the group consisting of carboxyl groups, alcoholic hydroxy groups and amide groups, said ionic charge is derived from the polymeric material containing said reactive groups wherein the amount of said groups is at least about 3%, by weight, and not more than about 30%, by weight, based on the total weight of said polymeric material, wherein said groups are heat reactive with (A), and wherein said percentages of (A) and (B), by weight, total 100% and are based on the total solids weight of (A) and (B); the improvement comprising, as said condensation product, the heat reaction product prepared by reacting at a temperature of at least 100°C in an acidic medium from about 90% to about 30% of a substantially water-insoluble, substantially fully etherified, substantially fully methylolated guanamine or substantially fully etherified, substantially fully methylolated melamine and from about 10% to about 70% of alkylated phenolic compound having the formula: R--O--C.sub.n H.sub.2n --O--C.sub.n H.sub.2n--m OH wherein R is an aryl radical, m is an integer from 0 to 3, and n is an integer from 2 to 4.