LAMINATED FILMS OF SYNTHETIC ORGANIC THERMOPLASTIC MATERIALS

摘要

1,247,442. Laminated films of synthetic organic materials. MOBIL OIL CORP. 25 Feb., 1969 [21 March, 1968], No. 10058/69. Headings B5B and B5N. A laminar flexible film structure comprises at least two synthetic organic thermoplastic film layers laminated together, (a) one of the layers being a support layer comprising a non-foamed continuous film layer, and (b) a second layer comprising a foam layer thin enough to constitute an open network of foam material on the exterior surface of the structure exposing the non-foamed support layer through random openings in the network of foam material. The thickness of the foam layer may be from 0À5 to 1À0 mil and the total thickness of the structure may be less than 10 mils. The foam layer may be not co-extensive with the support layer. The support layer may comprise polyethylene, polypropylene or polybutene and the foam layer an ethylene-vinyl acetate copolymer. The structure may be made by extruding at least two synthetic organic thermoplastic film-forming materials through a die orifice to form the layers of the laminate, one of the layers being the non-foamed continuous support layer and a second being the foamed layer formed with the aid of a sufficient incorporated blowing agent to constitute an open network of foam layer on the exterior of the structure, the non-foamed support layer being exposed through random openings in the network of foam material, and the width of the die orifice which forms the foamed layer being such that the thickness of the foamed layer does not exceed 0À1 mil. The structures of the invention may be made from a wide variety of film-forming synthetic organic thermoplastic materials such as, for example, polyolefins, polyvinyls, polyanides, polystyrenes, styrene copolymers and polyvinylidine chlorides. In the specific examples, tubular laminar structures are formed by simultaneously co-extruding through a single annular die orifice a layer of a polymer of a lower mono-olefin and a layer of a foamed ethylene-vinyl acetate copolymer.