Abstract: A composition suitable for use as a coating composition depositable by cationic electrodeposition which has improved edge protection capability containing, in addition to the conventional ingredients used in compositions for cationic electrocoat, such as an aqueous cationic resin, micro-resin particles of a size sufficient to be water dispersible which particles comprise an internally crosslinked polymer of (A) an active hydrogen containing monomer and (B) a monomer containing at least two active double bonds, which polymer further contains a cationic group in sufficient proportion to allow the micro-resin particle to be water dispersed.

Abstract: A composite paint film coating formed on a steel sheet of an automotive vehicle body. The composite paint film coating is comprised of an electrodeposition paint film (I) coated on the steel sheet, and an intermediate paint film (II) coated on the first paint film. The electrodeposition paint film has a minimum melt viscosity not less than 0.2 during hardening. The electrodepositon paint film is formed of cathodic electrodeposition paint composition which includes a cationic thermosetting resin (1), and an already cross-linked particulate resin (2). The particlate resin is an addition-polymer formed between a fist compound (A) having at least two primary amino groups in a molecule, and a second compound (B) having at least two .alpha.,.beta.-ethylenic unsaturated groups. The particulate resin has an average particle size ranging from 0.01 to 1 .mu.m. The weight ratio ((2)/(1)) in solid content between the particulate resin (2) cationic thermosetting resin (1) is within a range from 0.03 to 0.15.

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.