Patent ID: 7722931

Claim:
A method for forming a multi-layer coating film comprising sequentially applying an primer coating composition, a base coating composition and a clear coating composition on a substrate; and simultaneously curing the applied three layers by baking, wherein the primer coating composition comprises: a film forming binder and an organic liquid carrier, and optionally pigment(s) in a pigment to binder weight ratio of about 1:100-150:11; and the binder contains about: (a) about 30 to 80% by weight, based on the weight of the binder, of a hydroxyl functional polyester resin; (b) about 10 to 30% by weight, based on the weight of the binder, of a crosslinking agent selected from the group consisting of a melamine resin, a blocked polyisocyanate resin, or a mixture thereof; (c) about 10 to 40% by weight, based on the weight of the binder, of a graft polymer comprising a non-crosslinked core of acrylic polymer which is substantially non-soluble in non-polar organic solvent and, grafted to the core, a plurality of substantially linear acrylic stabilizer components, each of which is soluble in the non-polar organic solvent and has one end of the stabilizer molecule grafted to the core and a weight average molecular weight of about 10,000 to 100,000.