Patent ID: 8048491

Claim:
A multilayer coating film-forming method which comprises applying onto a coating object a base coat paint to form a base coating film, applying onto the formed uncured base coating film a clear coat paint to form a clear coating film, and heating the base coating film and clear coating film to cure the two films simultaneously, wherein the clear coat paint comprises a carboxyl group- and/or cyclic acid anhydride group-containing compound (A), polyepoxide (B) and an organic solvent (C) having a boiling point of 240° C. -300° C. and a solubility in water not higher than 20 g/100 g of water at 20° C. ,and in that the content of the organic solvent (C) is, based on the combined amount of the carboxyl group- and/or cyclic acid anhydride group-containing compound (A) and polyepoxide (B), 2-20 mass %, said clear coat paint further containing a latent curing catalyst (D) comprising tertiary amine (a) and acidic phosphoric acid ester (b), the tertiary amine (a) being a compound represented by a general formula, (R 1 R 2 R 3 N), wherein R 1 and R 2 and R 3 may be the same or different, at least one of which is a hydrocarbon group having at least 8 carbon atoms optionally substituted with halogen or hydroxyl group.