Epoxy-paste adhesives resistant to wash-off

摘要

This invention relates to compositions useful as adhesives and more particularly to the preparation of heat-curable epoxy-based adhesive compositions that are resistant to being washed off substrate surfaces prior to being cured. The incorporation of a solid diene-based rubber, in particular an acrylonitrile-butadiene copolymer rubber having a relatively high Mooney viscosity, significantly enhances the wash-off resistance of the adhesive, while still allowing the adhesive to be readily dispensed by pumping under high shear conditions.

主权项

1. A pumpable and wash-off resistant epoxy paste adhesive comprising: A) at least one epoxy resin; B) from 1 to 8 weight %, based on the total weight of the epoxy paste adhesive, of at least one solid diene-based rubber, wherein the solid diene-based rubber does not take the form of a core/shell particle where a central core is surrounded by an outer shell having a different composition than the core and wherein the solid diene-based rubber is comprised of from 25 to 35 weight percent acrylonitrile and 65 to 75 weight percent butadiene; C) at least one heat-activated latent curing agent; and D) at least one impact modifier/toughening agent selected from the group consisting of epoxy-based prepolymers obtained by reacting one or more amine-terminated polymers with one or more epoxy resins.