Patent ID: 8247035

Claim:
A method for forming multilayer coating film by successively conducting the following steps (1)-(4): (1) a step of applying onto a coating object a water-based first coloring paint (A) to form the first coloring coating film, (2) a step of applying a water-based second coloring paint (B) on the first coloring coating film as formed in the step (1), to form the second coloring coating film, (3) a step of applying a clear paint (C) on the second coloring coating film as formed in the step (2), to form the clear coating film, and (4) a step of simultaneously baking the first coloring coating film, second coloring coating film and clear coating film as formed in the steps (1)-(3), wherein the water-based first coloring paint (A) comprises polyester resin (X) and curing agent (Y), the polyester resin (X) containing benzene ring and/or cyclohexane ring in its molecules, their combined content in the polyester resin being within a range of 1.0-2.2 mols/kg (solid resin content); and that the curing agent (Y) is at least one compound selected from the group consisting of isocyanate group-containing compound (a), oxazoline group-containing compound (b), carbodiimide group-containing compound (c), hydrazide group-containing compound (d) and semicarbazide group-containing compound (e).