| 摘要 |
An object of the present invention is to provide a method for forming a multilayer coating film, capable of achieving excellent curability under low-temperature, short-time conditions, and forming a multilayer coating film having excellent chipping resistance and an excellent finished appearance. This method comprises sequentially applying an aqueous first colored coating composition (X), an aqueous second colored coating composition (Y), and a clear coating composition (Z) to a substrate, and simultaneously bake-curing the resulting multilayer coating film. In this method, the aqueous first colored coating composition (X) comprises an aqueous film-forming resin (A) and a specific blocked polyisocyanate compound (B), and the clear coating composition (Z) comprises a hydroxy-containing acrylic resin (K) having a hydroxy value in a specific range, a polyisocyanate compound (L), and an organometallic catalyst (M) containing a metal compound (M1) selected from a specific range and an amidine compound (M2). |
| 主权项 |
1. A method for forming a multilayer coating film, the method comprising:
applying an aqueous first colored coating composition (X) to a substrate to form a first colored coating film; applying an aqueous second colored coating composition (Y) to the uncured first colored coating film to form a second colored coating film; applying a clear coating composition (Z) to the uncured second colored coating film to form a clear coating film; and simultaneously curing the uncured first colored coating film, the uncured second colored coating film, and the uncured clear coating film,wherein the aqueous first colored coating composition (X) comprises an aqueous film-forming resin (A) and a blocked polyisocyanate compound (B) having at least one blocked isocyanate group selected from blocked isocyanate groups represented by Formula (I) below:wherein R1 represents isopropyl, R2, R4, and R5 each independently represent C1-12 hydrocarbon, and R3 represents linear or branched C1-12 alkylene,blocked isocyanate groups represented by Formula (II) below:wherein R2, R3, R4, and R5 are as defined above, andblocked isocyanate groups represented by Formula (III) below:wherein R2, R3, R4, and R5 are as defined above, and R6 represents isopropyl, and wherein the clear coating composition (Z) comprises a hydroxy-containing acrylic resin (K) having a hydroxy value of 85 to 215 mg KOH/g, a polyisocyanate compound (L), and an organometallic catalyst (M) containing a metal compound (M1) containing one or more metals selected from the group consisting of zinc, tin, zirconium, bismuth, lead, cobalt, manganese, titanium, aluminum, and molybdenum, and an amidine compound (M2). |
