| abstract |
A method for forming a coating film is here disclosed which comprises the steps of coating a member with a coating material containing a pigment for a thermosetting base coat, overcoating the coated member with a coating material for a thermosetting clear coat in a wet-on-wet coating manner, and then thermosetting the uncured coating films simultaneously; a binder component in the coating material for the base coat comprising 50 to 90% by weight of an acrylic copolymer having a hydroxyl value of from 40 to 80 mg KOH/g and an acid value of from 0.5 to 30 mg KOH/g and a glass transition temperature of from -40 DEG to 20 DEG C. which is obtained by copolymerizing 10 to 40% by weight of a hydroxyl group-containing (meth)acrylic ester, 0.2 to 10% by weight of a carboxyl group-containing vinyl monomer, 30 to 89.8% by weight of a (meth)acrylic ester and 0 to 30% by weight of another vinyl monomer, and 10 to 50% by weight of a curing agent; a binder component in the coating material for the clear coat comprising an acrylic copolymer having a hydroxyl value of from 50 to 180 mg KOH/g, an acid value of from 2 to 40 mg KOH/g and a glass transition temperature of from -40 DEG to 20 DEG C. which is obtained by copolymerizing 5 to 60% by weight of a fluorine-containing (meth)-acrylic ester, 10 to 60% by weight of a hydroxyl group-containing (meth)acrylic ester, 0.2 to 10% by weight of a vinyl monomer containing an acidic group, 15 to 70% by weight of a (meth)acrylic ester and 5 to 50% by weight of another vinyl monomer, and a polyisocyanate compound; a ratio X/Y of an equivalent (X) of the OH group present in the acrylic copolymer to an equivalent (Y) of the NCO group in the polyisocyanate compound being in the range of from 1/0.5 to 1/1.5. |