| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayer coating film formation method by a 3C1B system where the multilayer coating film having excellent coating film appearance, being excellent in chipping resistance and coating film hardness and being satisfied with scratch resistance, water resistance, acid resistance and the like can be obtained.SOLUTION: An aqueous intermediate coating and an aqueous base coating include a core/shell type resin emulsion (A) consisting of an acrylic resin (A1) of a core part and a polyurethane resin (A2) of a shell part. The acrylic resin (A1) has a hydroxyl value of 10-30 mgKOH/g, an acid value of 0-10 mgKOH/g, a glass transition temperature of 0-100°C. The polyurethane resin (A2) has a hydroxyl value 20-80 mgKOH/g, an acid value of 10-60 mgKOH/g, a number average molecular weight of 2,000-10,000 and a solid content mass ratio expressed as {(A1) component/(A2) component} of 0.80-1.25. |
