Coating composition and method for forming coating film using same

A cationic electrodeposition paint composition comprising:

• an amino group-containing epoxy resin;
• a blocked polyisocyanate obtained by reacting a polyisocyanate compound and an active hydrogen-containing component containing propylene glycol;
• and
• a cationic electrodepositing gelled microparticulate polymer, wherein:
• the amino group-containing epoxy resin is a polyol-modified amino group-containing epoxy resin obtained by reacting a polycaprolactone polyol compound and an amino group-containing compound with a modified epoxy resin,
• the modified epoxy resin is obtained by adding caprolactone to a hydroxyl group-containing epoxy resin,
• the cationic electrodepositing gelled microparticulate polymer is obtained by crosslinking an acrylic copolymer containing a hydrolyzable alkoxysilane group and a cationic group;
• and
• a blending ratio of the cationic electrodepositing gelled microparticulate polymer in the cationic electrodeposition paint composition is, in terms of a solid content ratio, from 0.1 to 20 parts by mass relative to total 100 parts by mass of the amino group-containing epoxy resin and the blocked polyisocyanate compound.