Patent ID: 6534121
Filing Date: 2003-03-18
Classification: B05D,C08G,C09D

Abstract:
A method of coating a bare untreated metal substrate, the method comprisingproviding a bare, untreated metal substrate, the substrate being substantially free of mechanical and/or chemical alterations, applying a two-component urethane coating composition directly to the bare, untreated metal substrate so as to make a coated metal substrate, at least one component of said two-component urethane coating composition comprising a mixture of compound (I) and compound (II) wherein compound (I) has an acid number of from 70 to 120 mg KOH/g, a hydroxyl number of from 200 to 400 mg KOH/g, a number average molecular weight of from 150 to 3,000 and is the reaction product of (a) at least one difunctional carboxylic acid, (b) at least one trifunctional polyol, (c) at least one chain stopper, and (d) phosphoric acid, and compound (II) comprises one or more carboxy phosphate esters having the formula: â€ƒwherein M is hydrogen, metal, or ammonium, x is a number from 0 to 3, R is an C5-C40 aliphatic group having one or more â€”COOR1 groups, wherein R1 is H, metal, ammonium, C1-C6 alkyl, or C6-C10 aryl, and sanding at least a portion of the coated metal substrate within two hours from the time the two-component urethane coating composition was applied to the bare, untreated metal substrate, said coated metal substrate being subjected to temperatures of no more than 140Â° F. prior to sanding, 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, Test Method B.