Patent ID: 8580385

Claim:
A method for forming a multilayer coating film comprising sequentially performing the following steps (1) to (4) on a substrate: step (1): forming a first colored coating film by applying an aqueous first colored coating composition (X); step (2): forming a second colored coating film by applying an aqueous second colored coating composition (Y) on the first colored coating film formed in step (1); step (3): forming a clear coating film by applying a clear coating composition (Z) on the second colored coating film formed in step (2); and step (4): bake-drying the first colored coating film, the second colored coating film, and the clear coating film formed in steps (1) to (3) all at once, wherein the aqueous first colored coating composition (X) is an aqueous coating composition comprising an acrylic resin (A), a curing agent (B), and a urethane resin emulsion (C), and the first colored coating film formed from the aqueous first colored coating composition (X) has a water swelling rate of 100% or less and an organic solvent swelling rate of 251% or less; the urethane resin emulsion (C) is produced using a polyisocyanate component and a polyol component as starting materials; the polyisocyanate component contains an alicyclic diisocyanate; the polyol component contains a diol component; the diol component contains a polycarbonate diol; and the polycarbonate diol is produced with a starting material comprising 50 mass % or more of a compound comprising a hydrocarbon group having 6 or more carbons.