Patent ID: 7807228

Claim:
A method of forming a luster coating film, comprising the steps of: (1) applying an aqueous luster thermosetting base coating composition (A), the solids content of the base coating composition (A) being about 5 to about 15 wt. % to a substrate in four or five stages, in such a manner that the thickness of the base coating composition (A) applied in the first stage becomes 1 to 5 μm when cured, the thickness of the base coating composition (A) applied in each of the second and subsequent stages becomes 0.3 to 5 μm when cured, and the total thickness of the base coating composition (A) applied in all of the stages in step (1) is 10 to 15 μm when cured; (2) applying a thermosetting clear coating composition (B) over the uncured or heat-cured coating layer of the base coating composition (A); and (3) heating the two-layer coating comprising the base coating composition (A) and clear coating composition (B) to obtain a cured two-layer coating film; wherein, in step (1), the solids content of the aqueous luster thermosetting base coating composition (A) one minute after the application in each stage is at least 40 wt. %; and wherein, in step (1), after each coating stage, the applied composition is allowed to stand, or is preheated at about 50 to about 80° C.