| abstract |
A process of forming a multilayer coating film comprising the following steps 1-1 to 1-4: step 1-1: a step of coating an article to be coated with a primer coating composition (X) and formation of an uncured primer coating film on the article to be coated, step 1-2: a step of coating the article to be coated having the uncured primer coating film with an aqueous color coating composition (Y1) for a base coat, and formation of an uncured base coat coating film thereon, step 1-3: a step of coating the article to be coated having the uncured primer coating film and the base coat coating film uncured with a clearcoat composition (Z), and formation of an uncured clearcoat film thereon, and step 1-4: a step of curing the re-film uncured primer coating, uncured basecoat coating film and uncured clearcoat film by heating, wherein the aqueous color coating composition (Y1) comprises a hydroxyl-containing resin (A), in the that the hydroxyl-containing resin (A) contains an aqueous dispersion of hydroxyl-containing acrylic resin (A11), and a blocked polyisocyanate compound (B) having at least one blocked isocyanate group selected from the group consisting of represented blocked isocyanate groups by the following formula (I): ** (See formula) ** in which R1, R2, R4 and R5 independently represent a C1-12 hydrocarbon group, and R3 represents a C1-12 straight or branched chain alkylene group, blocked isocyanate groups represented by the following formula (II): ** (See formula) ** in which R2, R3, R4 and R5 have the same definitions as above and blocked isocyanate groups represented by the following formula (III): ** (See formula) ** in which R2, R3, R4 and R5 have the same definitions as above, and R6 represents a C1-12 hydrocarbon group |