Patent ID: 7150899
Filing Date: 2006-12-19
Classification: B05D,Y02P

Abstract:
1. A method for forming a coating film on a plastic substrate which comprises the steps of: (1) coating the plastic substrate with an aqueous white primer (A) having a water content of about 15% to about 48% by weight, wherein the aqueous white primer (A) is characterized by forming a coating film having a lightness level (L* value) of about 80 or more based on the L*a*b* color system as defined in JIS Z 8729, in an assay where a plastic substrate is spray-coated with the primer (A) to a dry coating thickness of 30 to 40 μm, and dried at 80° C. to 120° C. for 20 to 40 minutes; (2) heating the thus formed coating film of the primer (A) to adjust the water content of the film to within the range of about 1% to about 10% by weight and the surface electrical resistivity value of the film to less than about 10 (3) electrostatically coating the thus adjusted coating film of the primer (A) with a thermosetting clear colored coating composition (B); (4) electrostatically coating the uncured coating film of the clear colored coating composition (B) with a thermosetting clear coating composition (C); and (5) baking the three-layer coating film of the coating compositions (A), (B) and (C) to obtain a cured multilayer coating film having a lightness value (N value) of about 8.5 or more based on the Munsell color system as defined in JIS Z 8721.