Adhesive compositions and method employing same

Abstract

Improved, fast curing adhesives, with and without fillers, and articles bonded therewith are provided. The adhesive comprises a first part made up of a thermoplastic, non-reactive elastomeric polymer dissolved in an addition polymerizable combination of an acrylic or methacrylic monomer, a copolymerizable monomer containing at least one free carboxylic acid group, and a non-activated free radical addition polymerization catalyst system, and a second part comprising an activator for the free radical catalyst system. Exemplary of such a formulation is a first part made up of a elastomer, e.g. an acrylonitrile/butadiene rubber dissolved in a mixture of acrylic acid and methyl methacrylate, each of the three components being present in equal amounts. About 5 weight percent benzoyl peroxide and about 0.1 weight percent hydroquinone are dissolved in the mix. The resulting formulation has a high degree of relative stability in the absence of an activator for the benzoyl peroxide. An appropriate second part, i.e., activator, comprises a tertiary amine, such as N,N-dimethyl aniline, diethyl aniline, N,N-dimethyl-p-toluidine. The second part may also contain an oxidizable heavy metal salt or other known acceleration for such free radical catalyst systems. In one modification the activator may be encapsulated in insoluble, rupturable microspheres to form a one-liquid adhesive.