Method for improving resistance to water spotting and acid etching of coatings by exposure to UV radiation
AssigneePPG Industries, Inc.
InventorsWayne H. Tyger, Raymond F. Cornuet, Jr., B. Keith Johnston
Life of this patent
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Abstract
A method for increasing the resistance of a coating such as a color/clear composite coating to water spotting and acid etching is disclosed. The method involves exposing the coated substrate to ultraviolet radiation after heat curing of the coating.
Claims12
An improved method for applying a coating to an article of manufacture intended for outdoor exposure other than a testing specimen which comprises applying to the substrate a film-forming composition being essentially free of radiation polymerizable ethylenic unsaturation, containing an active hydrogen-containing polymer and an aminoplast curing agent to form a coated article and heating said coated article to cure said coating, characterized in that after heating the coated article to cure the coating to form a hard solvent-resistant coating, the coated article is exposed to an artificial source of ultraviolet radiation, in an oxygen-containing atmosphere, in an amount sufficient to increase the resistance of the coating to water spotting and acid etching when the coated article is subsequently exposed to natural weathering.
An improved method for applying a coating to an article of manufacture intended for outdoor exposure other than a testing specimen which comprises applying to said article a colored film-forming composition to form a base coat and applying to said base coat a clear film-forming composition containing an active hydrogen-containing polymer and an aminoplast curing agent to form a transparent top coat over the base coat to form a coated article and heating said coated article to cure said clear coat, characterized in that after heating the coated article to cure the clear top coat to form a hard solvent-resistant coating, the coated article is exposed to an artificial source of ultraviolet radiation, in an oxygen-containing atmosphere, in an amount sufficient to increase the resistance of the clear coat to water spotting and acid etching when the coated article is subsequently exposed to natural weathering.
Dependencies are inferred from the claim text.