Process for electrodepositing coatings on metal

Claim 1

A process for electrodepositing films on electroconductive metal comprising immersing said metal in an aqueous dispersion of a mixture of from about 5% to about 40%, by weight, of (A) a substantially water-insoluble, substantially fully etherified, substantially fully methylolated melamine; a substantially water-insoluble, substantially fully etherified, substantially fully methylolated guanamine or a substantially water-insoluble, substantially fully butylated urea-formaldehyde reaction 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, amine groups and amide groups, wherein the amount of said groups is at least 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 as a curing catalyst for (A) and (B) from about 0.2% to about 10%, by weight, of (C) an aromatic sulfonic acid compound having an equivalent weight of at least 250 and subjecting the aqueous dispersion to electrophoresis in order to deposit the catalyzed mixture of (A) and (B) on the metal as an adherent film; wherein the percentages of (A) and (B), by weight, total 100% and are based on the total solids weight of (A) and (B) and the percentage weight of (C) is also based on the total solids weight of (A) and (B).