Primer composition for improving the bonding of a urethane adhesive

Abstract

In one aspect, this invention is a primer which comprises a solution of: (a) a polyester resin of a carboxylic acid and a glycol; and (b) a polymethylene poly(phenyl isocyanate), diphenylmethane diisocyanate, or mixture thereof; in a volatile solvent, wherein the weight ratio of (a):(b) is in the range of from about 0.25:1.0 to 2.0:1.0. In a second aspect, this invention is a primer which comprises a solution of: (a) 5-18 weight percent of a polyester resin of a carboxylic acid and a glycol; and (b) 6-17 weight percent of a polymethylene poly(phenyl isocyanate), diphenylmethane diisocyanate, or mixture thereof; in a volatile solvent. It has been discovered that the primer of the invention advantageously provides improved adhesion characteristics of metal-to-glass bonding when used to prime paint-coated metal substrates before the application of a urethane adhesive, particularly when used with a "fast cure" adhesive comprised of an isocyanate-functional prepolymer and dimorpholinediethyl ether.

Dependencies are inferred from the claim text.