Paint composition for cation electrodeposition painting

Abstract

A paint composition for cation electrodeposition painting, used for painting automotive vehicle body etc. The paint composition comprises basic unsaturated modified epoxy ester expressed by the general formula: ##STR1## where R.sub.1 and R.sub.2 are functional groups at least one of which is .alpha., .beta.-ethylenic double bond containing groups and the remainder is an unsaturated fatty acid chain; R.sub.3 is a group expressed by the formula: ##STR2## and X and Y are functional groups whose total number is n+1 in which not less than one functional group is a group containing both a tertiary amine function and a urethane function, and the remainder are hydroxyl groups (--OH), n being an integer ranging from 1 to 20. The paint composition further comprises basic unsaturated modified polydiene compound which is a reaction product of polydiene compound having a molecular weight ranging from 500 to 10,000 and unsaturated double bonds with iodine value ranging from 50 to 500, and containing oxirane oxygen ranging from 3 to 12% by weight, (2) a secondary amine, and .alpha., .beta.-ethylenic unsaturated carboxylic acid, thereby improving ability for covering the edge of a metal member to be painted.

Dependencies are inferred from the claim text.