Cathodic electrocoating resin system comprising the reaction product of polyepoxide, a polyamine and a monocarboxylic acid

Claim 1

A resinous composition comprising the reaction product of (A) a monocarboxylic acid which contains one carboxylic acid group and no other groups reactive with amine groups, said monocarboxylic acid having about 8 to 24 carbon atoms per molecule; and (B) the reaction product of (1) a polyepoxide resin derived from a dihydric phenol and an epihalohydrin, said polyepoxide resin having a 1,2-epoxide equivalent weight of about 400 to about 4000; and (2) a polyamine having at least 2 amine nitrogen atoms per molecule, at least 3 amine hydrogen atoms per molecule and no other groups reactive with epoxide groups, wherein (1) and (2) are reacted to form an epoxide-amine adduct, wherein (A) and (B) are reacted to form amide groups, wherein about 1 mol of (2) is reacted with each epoxide equivalent of (1), about 2 to about 6 mols of (A) are reacted per each mol of (1) and wherein said resinous composition has a weight per active nitrogen of about 200 to about 600.