Method for applying a color-plus-clear composite coating to a substrate

摘要

A method of applying a color-plus-clear composite coating to a substrate is provided comprising: applying to the substrate a colored film-forming composition to form a base coat and applying to the base coat a clear film-forming composition to form a transparent top coat over the base coat. Prior to application to the base coat, the clear film-forming composition is heated to a temperature and for a time sufficient to lower its viscosity such that the composition can be atomized and applied as a smooth continuous film. At a temperature of 20-25 DEG C., the clear film-forming composition has a high viscosity such that it cannot be atomized and applied as a smooth continuous film. The clear film-forming composition comprises (1) about 65 to about 85 percent by weight, based on the total weight of resin solids in the clear film-forming composition, of a hydroxyl functional acrylic polymer having a weight average molecular weight of about 5000 to about 25,000 as determined by gel permeation chromatography using a polystyrene standard, and having a glass transition temperature of at least about 10 DEG C.; and (2) about 15 to about 35 percent by weight, based on the total weight of resin solids in the clear film-forming composition, of an aminoplast crosslinking agent.