| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for forming a composite-layered coating film excellent in appearance by preventing the formation of a mixed layer between an intercoating film and a base coating film by a three-coat one-bake method. Ž<P>SOLUTION: The method includes applying an aqueous intercoating material, aqueous base coating and clear coating onto the surface of an electrodeposition coating film, and then baking the formed coating films and curing at the same time to form the composite-layered coating film. The base coating contains polyether polyol which has a primary hydroxyl group in the molecule and an average number of 0.02 or above of the group and the number average molecular weight of which is 300-3,000 and the water tolerance of which is 2.0 or above, and an emulsion of an acrylic resin obtained from an α,β-ethylenic unsaturated monomer with an acid value of 3-50 mg/KOH. The intercoating material contains an emulsion of acrylic resin with a solid component hydroxyl value of 50-120 and a solid component acid value of 20-60 mg/KOH, a completely alkyl-etherified melamine resin having a 1-4C alkyl side chain and a specific carbodiimide compound, and the internal stress of the coating film alone of the intercoating material is within a specific range. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
