Patent ID: 7045575

Claim:
A cationic electro-deposition coating composition, which comprises: component (A): an amino-containing epoxy resin (A) obtained by adding an amino-containing compound (a-2) to an epoxy resin (a-1) having an epoxy equivalent of from 400 to 3000, component (B): an amino-containing acrylic resin (B) obtained by adding an amino-containing compound (b-4) to a copolymer resin obtained by radical copolymerization of, as essential components, a polylactone-modified hydroxyl-containing radical copolymerizable monomer (b-1), which is obtained by adding a lactone to a hydroxyl-containing acrylic monomer (b) and is represented by the following formula (1) or (2): CH 2 ═C(R 1 )—R 2 —O—(CO—(CH 2 ) m —O—) 1 —H (1) (wherein, R 1 represents H or an alkyl group, R 2 represents any one of —(CH 2 ) n —, —(CO)O—(CH 2 ) n — and —O—(CO)—(CH 2 ) n —, 1 stands for an integer of 3 to 10, m stands for an integer of 4 to 8 and n stands for an integer of 1 to 10), (wherein, R 1 represents H or an alkyl group, R 2 represents any one of —(CH 2 ) n —, —(CO)O—(CH 2 ) n — and —O—(CO)—(CH 2 ) n—, 1 stands for an integer of 3 to 10, k stands for an integer of 0 to 4 and n stands for an integer of 1 to 10), and glycidyl (meth)acrylate (b-2), and another radical copolymerizable monomer (b-3); and component (C): a blocked polyisocyanate curing agent (C) as a curing component, the component (A), component (B) and component (C) being added in amounts of 5 to 80 wt %, 5 to 80 wt % and 10 to 40 wt %, respectively, based on the total solid content of the components (A), (B) and (C); wherein the amino-containing acrylic resin (B) is obtained by adding the amino-containing compound (b-4) to a resin obtained by radical copolymerization reaction of a mixture of 5 to 40 wt % of the polylactone-modified hydroxyl-containing radical copolymerizable acrylic monomer (b-1), which is obtained by adding a lactone to hydroxyethyl (meth)acrylate and is represented by the formula (1) or (2), 2 to 30 wt % of glycidyl (meth)acrylate and 30 to 93 wt % of another radical copolymerizable monomer (b-3), each based on the total solid content of the monomers constituting the amino-containing acrylic resin (B).