Multiple-layer tubing

A process for producing a multiple layered film in the shape of a tube comprising:

• a central layer of a cellulose hydrate-based material;
• a first layer of the inside surface of said central layer, said first layer comprising a continuous film of a first polymer comprising thermoplastic synthetic resinous material selected from a vinylidene chloride copolymer having a major proportion of vinylidene chloride, said thermoplastic synthetic resinous film being impermeable to water and water vapor;
• a second layer on the outside surface of said central layer, said second layer comprising a film of a second polymer different from said first polymer and comprising a synthetic elastic copolymer selected from the group consisting of (a) a copolymer comprising a major proportion of an acrylate, a methacrylate or a mixture thereof and a minor portion of acrylic acid, methacrylic acid or a mixture thereof, (b) a copolymer comprising a major proportion of an aliphatic diene, selected from the group of butadiene, isoprene, chloroprene or a mixture thereof, and (c) a blend of chemically different copolymers of said elastic copolymers, said synthetic elastic copolymer film being permeable to water and water vapor;
• said process comprising the steps of
• coating a carrier tube of a cellulose hydrate-based material on its inside surface with said first layer of a synthetic thermoplastic polymer;
• applying to the outside surface of said carrier tube an aqueous dispersion of said synthetic elastic copolymer, wherein the major proportion of said copolymer comprises particles having a size not larger than about 0.08 .mu.m, to produce on the outside surface of the carrier tube a layer of copolymer having a thickness corresponding to a weight per unit area of from about 0.5 to 8 gram of copolymer per m.sup.2 of carrier tube surface;
• and
• drying the tube to remove the water from said dispersion.