Abstract: According to the present invention, provided is an electrodeposition coating composition, which can form an electrodeposition coating film having excellent corrosion resistance and coating film smoothness. The present invention relates to an electrodeposition coating composition comprising a soluble metal compound (A), amine-modified resin (B) and curing agent (C), wherein the resin (B) has an average molecular weight of 1,000 to 5,000, an amine value of 20 to 100 mgKOH/g and a hydroxyl value of 50 to 400 mgKOH/g, a theoretical residual hydroxyl value when the resin (B) and curing agent are reacted in an electrodeposition coating film is from 30 to 350 mgKOH/g, and the ratio (R) of the concentration of the theoretical residual hydroxyl value to the concentration of the compound (A) in the composition, based on the total of the solid content of the resin (B) and the curing agent in the composition satisfies the relationship (4,000<R<400,000).

Abstract: According to the present invention, provided is an electrodeposition coating composition, which can form an electrodeposition coating film having excellent corrosion resistance and coating film smoothness. The present invention relates to an electrodeposition coating composition comprising a soluble metal compound (A), amine-modified resin (B) and curing agent (C), wherein the resin (B) has an average molecular weight of 1,000 to 5,000, an amine value of 20 to 100 mgKOH/g and a hydroxyl value of 50 to 400 mgKOH/g, a theoretical residual hydroxyl value when the resin (B) and curing agent are reacted in an electrodeposition coating film is from 30 to 350 mgKOH/g, and the ratio (R) of the concentration of the theoretical residual hydroxyl value to the concentration of the compound (A) in the composition, based on the total of the solid content of the resin (B) and the curing agent in the composition satisfies the relationship (4,000<R<400,000).