Moistureproof polyvinyl films

Films resistant to passage of water vapour comprise a polyvinyl chloride type resin and 0.5-3.0 per cent by weight of the film of a dialkyl ether having a m.p. above room temperature, each alkyl group of which contains from 10-18 carbon atoms. In suitable resins the elements of vinyl chloride make up at least 60 per cent of the resinous components, copolymers, terpolymers and mixtures of vinyl polymers and copolymers may be used. Unsaturated compounds which may be copolymerized with vinyl chloride include vinyl esters, ethers and aryl substituted products, e.g. styrene, vinyl naphthalene and dichlorostyrene; acrylic esters and nitriles, vinylidene chloride, butadiene and chloroprene, coumarone and indene. Plasticizers, stabilizers, solvents and modifiers may also be present, specified are dialkyl phthalates, trialkyl and triaryl phosphates, esters of dibasic acids, aryl alkyl polyethers and fatty acid esters, e.g. dibutyl sebacate, di- and tri-octyl phosphates, tricresyl phosphate and dicresyl carbitol, glycerol monostearate, lead oleate, glyceryl dicresyl ether, calcium stearate and methyl ethyl ketone. Suitable dialkyl ethers include one or more of dilauryl, dimyristyl, dicetyl, distearyl lauryl stearyl, lauryl cetyl and myristyl cetyl ethers and mixed ethers synthesized from fatty alkyl radicals derived from natural oils, fats and waxes, e.g. coconut oil, tallow and hydrogenated fish oil.