Rubber compounds are readily bonded to polyester reinforcing elements, particularly tire cords of polyester fibers, using a one-step dip process in which the dip consists essentially of an alkaline aqueous emulsion of a minor amount by weight of a mixture of a major amount by weight of a rubbery vinyl pyridine copolymer and a minor amount by weight of a heat reactable 2,6bis(2,4-dihydroxy phenylmethyl)-4-chlorophenol composition, wherein said emulsion is essentially free of alkali metal materials and wherein the emulsifier used in the emulsion is an ammonium salt or soap. High aged H-adhesions are obtained with this process.