Electrocoating composition with polyhydroxyamine and epoxy

Claim 1

An aqueous cathodic electrodeposition coating composition comprising a dispersion of a first polymer, a second polymer, enough of an organic acid to give the composition a pH about in the range of 6 to 7, and optionally a nitrogen resin crosslinker, said coating composition containing, by weight based on the first and second polymers, about 20-70% of a first polymer which is a copolymer comprising a backbone and a graft pendent to the backbone, said backbone containing amine functional groups and hydroxy functional groups, characterized in that said backbone contains at least about 0.13 equivalent of amine groups per 100 grams of first polymer and at least about 0.03 equivalent of hydroxyl groups per 100 grams of first polymer, and containing, by weight, the equivalent of about: (a) 35-90% amine functional monomers, (b) 10-60% hydroxy functional monomers, (c) 0-40% nonfunctional acrylic or methacrylix monomers, and (d) 0-5% chain-terminating monomers the total of (a), (b), (c) and (d) being 100% of said backbone, said graft comprising a monoglycidyl ester of at least one tertiary carboxylic acid containing 9-20 carbon atoms and being grafted to said amine groups in said backbone, said copolymer containing about 1-30% by weight of said graft, and, by weight based on the first and second polymers, about 80-30% of a second polymer which is an epoxy resin reacted with, based on the weight of said second polymer, about 80-150% of an entity selected from the group consisting of alkyl phenols, alkyl alcohols and alkyl hydroxy ethers, with 1-20 carbon atoms in the alkyl groups, hydroxyamines, fatty amines and mercaptans.