Abstract: In the preparation of an improved adhesive composition, an epoxy-based prepolymer is obtained by the reaction of one or more epoxy resins with amino-terminated polyethers and/or carboxyl-terminated butadiene-nitrile rubbers. In one embodiment of the invention, both a solid epoxy resin and a liquid epoxy resin, each of which is a diglycidyl ether of a polyphenol such as bisphenol A, are used. The epoxy-based prepolymer is mixed with an acrylate-terminated urethane resin (preferably, one based on a polyol having a number average molecular weight of at least about 400) and a heat-activated latent curing agent to make an adhesive composition which can be pumpable at room temperature. Curable adhesives capable of expansion to about 100% with high impact resistance after curing may be obtained by inclusion of expanding agents such as expandable microspheres.

Abstract: In the preparation of an improved adhesive composition, an epoxy-based prepolymer is obtained by the reaction of one or more epoxy resins with amino-terminated polyethers and/or carboxyl-terminated butadiene-nitrile rubbers. In one embodiment of the invention, both a solid epoxy resin and a liquid epoxy resin, each of which is a diglycidyl ether of a polyphenol such as bisphenol A, are used. The epoxy-based prepolymer is mixed with an acrylate-terminated urethane resin (preferably, one based on a polyol having a number average molecular weight of at least about 400) and a heat-activated latent curing agent to make an adhesive composition which can be pumpable at room temperature. Curable adhesives capable of expansion to about 100% with high impact resistance after curing may be obtained by inclusion of expanding agents such as expandable microspheres.

Abstract: In the preparation of an improved adhesive composition, a first reaction product is prepared by the reaction at an elevated temperature of a) 30 to 50 wt-% of an epoxy resin, solid at room temperature, which was prepared from bisphenol A and/or bisphenol F and epichlorohydrin with an epoxide equivalent weight of 400 to 700, b) 10 to 25 wt-% of an epoxy resin, liquid at room temperature, prepared from bisphenol A and/or bisphenol F and epichlorohydrin with an epoxide equivalent weight of 150 to 220, c) 35 to 50 wt-% amino-terminated polyethylene and/or polypropylene glycols and d) a carboxyl-terminated butadiene-nitrile rubber. The first reaction product is mixed with an acrylate terminated urethane resin, glass microspheres, expandable hollow plastic microspheres and a latent curing agent to make an adhesive composition which is pumpable at room temperature and capable of expansion to about 100% with high impact resistance after curing.