| 摘要 |
<p>1392666 Laminated films UNION CARBIDE CORP 21 Feb 1973 [22 Feb 1972] 8426/73 Headings B5B and B5N A laminated heat-shrinkable film for making bags for frozen poultry consists of (a) a biaxially oriented first layer comprising a first ethylene polymer which is either ethylene homopolymer having a density not greater than 0À93 or ethylene copolymer and which has a melt index of less than 2À3 and (b) a biaxially oriented second layer comprising a blend of an ionomer and a second ethylene polymer which is either ethylene homopolymer having a density not greater than 0À93 or ethylene copolymer and which may be the same as or different from the first ethylene polymer; each layer comprising at least 20% of the total film thickness. Vinyl acetate, acrylic acid, methacrylic acid, 1-4 alkyl acrylate, or 1-4 alkyl methacrylate may be used as comonomer with the ethylene, in a proportion of up to 20% by wt. The second ethylene polymer may have a melt index of up to 10. The ionomer may be a copolymer of an alkali metal or zinc salt of an unsaturated organic acid, e.g. acrylic or methacrylic acid, with ethylene, the salt forming 0À5 to 50 mol. per cent of the ionomer. The ionomer forms 1 to 60 wt. per cent of the second layer. The total film thickness is 1À5 to 3 mils. The layers are coextruded from melts in tubular form and biaxially oriented by inflation. The first layer forms the inner layer of a bag and can be heat sealed.</p> |
