Patent ID: 8293820

Claim:
A cationic electrodeposition coating composition comprising a cationic resin (A) and a blocked polyisocyanate (B) obtained by reaction between a polyisocyanate compound (b1) with two or more isocyanate groups, castor oil (b2) and a blocking agent (b3), wherein the blocked polyisocyanate (B) is obtained by reaction between the polyisocyanate compound (b1), castor oil (b2) and blocking agent (b3) at 0.02-0.5 as the equivalent ratio of the castor oil (b2) active hydrogen groups/polyisocyanate compound (b1) isocyanate groups, 0.5-1.2 as the equivalent ratio of blocking agent (b3) active hydrogen groups/polyisocyanate compound (b1) isocyanate groups, and 1.0-1.5 as the equivalent ratio of [castor oil (b2) active hydrogen groups+blocking agent (b3) active hydrogen groups]/[polyisocyanate compound (b1) isocyanate groups].