Patent ID: 7456234
Filing Date: 2008-11-25
Classification: C08K

Abstract:
1. A lead-free cationic electrodeposition coating composition which comprises an aqueous medium, a binder resin composed of a cationic epoxy resin and a blocked isocyanate curing agent dispersed or dissolved in the aqueous medium, a neutralizing acid in order to neutralize the cationic epoxy resin, an organic solvent, and a catalyst releasing metal ion, wherein the cationic epoxy resin is an oxazolidone ring-containing amine-modified epoxy resin having a glass transition temperature of 10 to 30 ° C. and a number average molecular weight of 1500 to 3000 , and the electrodeposition coating composition has a volatile organic content of 1 % by weight or less, a metal ion content of 200 to 400 ppm, and a neutralizing acid amount of 10 to 30 mg equivalent based on 100 g of binder resin solid content, wherein the metal ion is one or more selected from the group consisting of cerium ion, bismuth ion, copper ion, zinc ion, molybdenum ion and aluminium ion, and wherein the neutralizing acid is one or more selected from the group consisting of acetic acid, lactic acid, formic acid and sulfamic acid.