Abstract: A one-package stable rubber based curable composition contains:(a) a functional rubber polymer selected from the group consisting of functional homopolymers of polybutadiene, isoprene or neoprene; functional copolymers of polybutadiene, isoprene and/or neoprene; and functional copolymers of polybutadiene, neoprene or isoprene with an aliphatic or alicyclic unsaturated hydrocarbon; and(b) a vulcanization system comprising sulfur, wherein the composition contains at least 15 parts of functional rubber polymer per 100 parts of composition and at least 15 parts of sulfur per 100 parts of the total amount of all rubber polymers in the composition, with the proviso that the cured composition has an elongation not exceeding 15 percent and the functional groups present on the functional rubber polymer of (a) remain essentially unreacted during cure of the composition.

Abstract: A one package, stable curable composition contains:(a) a nonfunctional polydiene;(b) a polyepoxide;(c) a sulfur and zinc containing vulcanization system adapted to cure the polydiene and the polyepoxide; and(d) an anhydride containing material effective to promote adhesion of the curable composition to metal, wherein the anhydride containing material remains essentially unreacted with the epoxide and is combined in a manner to obtain dissolution of the anhydride containing material in the epoxide.The aforesaid curable composition is suitable for use as an adhesive or sealant.