. "The alkyl acrylate rubbers may optionally contain up to 30% by weight, based on the weight of the rubber, of such monomers as vinyl acetate, acrylonitrile, styrene, methyl methacrylate and/or vinyl ethers in copolymerized form and also relatively small quantities, preferably up to 5% by weight, based on the weight of the rubber, of crosslinking, ethylenically unsaturated monomers." . . . .