ELECTRODEPOSITION COATING COMPOSITION AND ITS PREPARATION

Disclosed herein is a cathodic electrodeposition coating composition, which includes (A) a cationic amino-containing epoxy resin, (B) a blocked polyisocyanate having neutralized amine, which is obtained by a process including steps of (i) reacting a polyurethane prepolymer containing isocyanate groups with at least one blocking agent selected from the group consisting of oximes, pyrazoles and active methylene compounds, to provide a partially blocked polyisocyanate, (ii) reacting remaining isocyanate groups in the partially blocked polyisocyanate with an amine compound having active hydrogen, to provide an amine-containing blocked polyisocyanates, and (iii) neutralizing the amine-containing blocked polyisocyanates with an acid, and (C) a curing catalyst. Further disclosed herein are a process for preparing the cathodic electrodeposition coating composition, and a coating bath for the cathodic electrodeposition including the cathodic electrodeposition coating composition.