Patent ID: 6472020
Filing Date: 2002-10-29
Classification: B05D,C08G,Y10T

Abstract:
A process for forming a multilayer coating film on automotive bodieswhich comprises applying a clear coating for top coating, by the wet-on-wet technique, onto a base coating containing a color pigment and/or a luster pigment as applied to a coated automotive panel and then heating the coat layers for curing, said base coating comprising, as resin constituents, a product obtained by grafting a silicate compound (A) onto a hydroxyl-containing acrylic resin or polyester resin and an amino and/or blocked polyisocyanate curing agent, the amount of said silicate compound (A) grafted being 0.1 to 50% by weight (on solids basis) relative to the total amount of said resin constituents, said clear coating for top coating being an acid/epoxy-curable or amino and/or blocked polyisocyanate-curable clear coating, said clear coating for top coating containing or being free of an alcohol-modified silicate compound (IV) or a silicate graft polymer (V), at least one of the resin constituents in said acid/epoxy-curable clear coating and said amino and/or blocked polyisocyanate-curable clear coating being obtained by grafting said silicate compound (A) when said clear coating for top coating contains neither said alcohol-modified silicate compound (IV) nor said silicate graft polymer (V), said silicate graft polymer (V) being obtained by grafting said silicate compound (A) onto a hydroxyl-containing polymer (V-a), the amount of said alcohol-modified silicate compound (IV) and/or the amount of said silicate compound (A) grafted being 0.1 to 30% by weight (on solids basis) relative to the total amount of said resin constituents, said silicate compound (A) being represented by the general formula (1): wherein m represents an integer of 1 to 50 and the R1's may be different and each represents a substituted or unsubstituted organic group containing 1 to 20 carbon atoms,and said alcohol-modified silicate compound (IV) being represented by the general formula (2): wherein n represents an integer of 1 to 50 and one or some of the R2's each represents a substituted or unsubstituted alkyl group containing 2 to 20 carbon atoms or a substituted or unsubstituted aralkyl group containing 7 to 20 carbon atoms and the remaining R2's respectively represent a methyl group.