PURPOSE: To obtain a coating film having excellent acid resistance, scratch resistance, water-repellency and durability of the water-repellency by a two-coat one-bake coating process using a clear paint having a specific composition.
CONSTITUTION: A coating surface is coated with a thermosetting paint containing a pigment. The formed coating film is coated with a clear paint composed mainly of (A) an acrylic polymer produced by the polymerization of (i) 5-40wt.% of a vinyl monomer containing alkoxysilane group and expressed by formula I (A is formula II or formula III; R1 is H or methyl; R2 is 1-6C bivalent saturated aliphatic hydrocarbon group; R3 and R4 are phenyl, 1-6C alkyl, etc.; R5 is 1-10C alkyl; (n) is 1-100), (ii) 5-50wt.% of an OH-containing vinyl monomer and (iii) 10-90wt.% of other copolymerizable monomer, (B) a low-molecular weight polyol having a weight-average molecular weight of 900-2,000, a hydroxyl value of 150-350mgK0H/g and an Mw/Mn ratio of ≤1.6 (Mw is weight-average molecular weight and Mn is number-average molecular weight), (C) an amino resin and (D) an OH-containing silicone resin having a surface tension of ≤25dyne/cm2. Both coating layers are simultaneously cured with heat to obtain a finished surface.
NAKAMURA ITARU
FUKUDA MITSUHIRO
YOKOYAMA TETSUYA
KANSAI PAINT CO LTD