The ethylenically unsaturated monomers copolymerizable with vinyl-chloride may be any of vinyl ethers such as cetyl vinyl ether; vinyl esters such as vinyl formate and vinyl acetate; vinylidene halides such as vinylidene chloride and vinylidene fluoride; vinyl halides other than vinyl chloride such as vinyl bromide and vinyl fluoride; alkyl acrylates having 1 to 18 carbon atoms in the alkyl such a