Method of coating bare, untreated metal substrates

Abstract

The present invention provides a method for coating bare, untreated metal substrates wherein a coating composition comprising one or more particularly defined additives is applied directly to a bare metal substrate which has not been chemically and/or mechanically altered. The invention provides a method of coating a bare untreated metal substrate. The method requires the steps of (i) providing a bare, untreated metal substrate, the substrate being substantially free of mechanical and/or chemical alterations, (ii) applying a two-component urethane coating composition directly to the bare, untreated metal substrate so as to make a coated metal substrate, and (iii) sanding at least a portion of the coated metal substrate within one hour from the time the two-component urethane coating composition was applied to the bare, untreated metal substrate. The resulting coated metal substrate has an initial adhesion loss of less than 20% as measured by a cross hatch adhesion test per ASTM D-3359 93. The invention further provides a method of refinishing a previously coated substrate. This method requires (i) providing a substrate having thereon a previously applied and cured coating film, (ii) removing substantially all of the previously applied and cured coating film from at least a portion of the substrate so as to make a bare metal subtrate substantially free of mechanical and/or chemical alterations, (iii) applying a two-component urethane coating composition directly to the bare, untreated metal substrate so as to make a coated metal substrate, and (iv) sanding at least a portion of the coated metal substrate within one hour from the time the two-component urethane coating composition was applied to the bare, untreated metal substrate, wherein the coated metal substrate has an initial adhesion loss of less than 20% as measured by a cross hatch adhesion test per ASTM D-3359 93.

Dependencies are inferred from the claim text.