Adhesion of polyurethane to EPDM elastomer

A method of adhering a polyurethane to the surface of a cured ethylene-propylene-non-conjugated diene terpolymer rubber article comprising mixing the said terpolymer rubber, prior to cure thereof, with a curative in amount sufficient to cure the terpolymer rubber and with a halogen donor selected from the group consisting of (1) N,N-dihalogenated aromatic sulfonamides wherein the sulfonamide nitrogen is bonded to two atoms of chlorine, bromine or iodine and the sulfonyl sulfur is bonded directly to the aromatic nucleus and (2) cyclic N-halogenated amides wherein a carbonyl carbon in the ring is bonded to two nitrogen atoms, each of said nitrogen atoms in turn being bonded to a halogen atom thereby forming the grouping ##EQU1## wherein X is chlorine, bromine or iodine, the amount of said halogen donor being sufficient to provide from 0.5 to 5 parts of halogen per 100 parts by weight of said terpolymer rubber, and thereafter subjecting the resulting mixture of terpolymer rubber and halogen donor to elevated temperature sufficient to cure the terpolymer rubber and at the same time bring about reaction between the terpolymer rubber and the halogen donor, subsequently applying to a surface of the thus-cured terpolymer rubber a polyurethane prepolymer which is a polyol-polyisocyanate reaction product in admixture with a bifunctional curative for the prepolymer in amount sufficient to cure the prepolymer, and thereafter subjecting the assembly to an elevated temperature sufficient to cure the prepolymer, whereby an adhesive bond is created between the cured polyurethane and the terpolymer rubber surface.