| 摘要 |
PROBLEM TO BE SOLVED: To provide an aqueous coating composition which can be cured at a low temperature and which has excellent coating stability and satisfactory crosslink density.SOLUTION: The aqueous coating composition includes: (A) an aqueous resin having a hydroxyl group and a carboxyl group; (B) a polyisocyanate compound; and (C) a hydrophilization modified carbodiimide compound; wherein (A) has, in terms of resin solid content, 80 to 200 mgKOH/g hydroxyl value and 10 to 40 mgKOH/g acid value and the ratio of the hydroxyl value to the value of the acid value of (A) is 3 to 15, the ratio of an equivalent weight of carbodiimide group included in (C) to the equivalent weight of the isocyanate group included in (B) is 0.01 to 0.20, (C) is represented by general formula (I), the ration of the equivalent weight of isocyanate group included in (B) to the equivalent weight of the hydroxyl group included in (A) is 0.6 to 1.5 and the ratio of the equivalent weight of the carbodiimide group included in (C) to the equivalent weight of acid radical included in (A) is 0.1 to 1.0. [ In the formula, X denotes a bifunctional organic group containing at least one carbodiimide group, Y denotes a structure formed by removing hydroxyl groups from the same or different polyalkylene glycol monoalkylether and Z denotes a structure formed by removing hydroxyl groups from a bifunctional polyol having a number average molecular weight of 200 to 5,000]. |
