| 摘要 |
1335610 Laminated films DOW CHEMICAL CO 16 Sept 1971 [16 Sept 1970] 43263/71 Headings B5B and B5N Laminated films suitable for use in packaging are prepared by coextrusion of (i) a first layer comprising a blend of polyvinylidene chloride or a normally crystalline vinyl chloride / vinylidene chloride copolymer and from 2 to 6% by weight of an ethylene/vinyl alkanoate copolymeric modifier and (ii) a second layer of an ethylene/ unsaturated ester copolymer as a tubular laminate and inflation orienting the product. Preferably the copolymeric modifier used in the first layer contains from 25 to 85% by weight ethylene and from 15 to 75% by weight of the vinyl alkanoate, examples of which are vinyl acetate, vinyl butyrate, vinyl propionate and vinyl 2-ethylhexoate. The second layer is preferably a copolymer containing 70 to 75% by weight ethylene and 25 to 30% by weight vinyl acetate or 70 to 92% by weight ethylene and 30 to 8% by weight ethyl acrylate. In an example a tubular laminated film is prepared by coextrusion of the two film layers, the film being oriented by inflation prior to wind-up and comprising a first layer of vinylchloride/vinylidene chloride copolymer modified with 3% by weight of ethylene/vinyl acetate copolymer and a second layer of the same ethylene/vinyl acetate copolymer used as modifier in the first layer. |
