| 摘要 |
1,166,458. Multilaminate thermoplastics film. CROWN ZELLERBACH CORP. 30 Sept., 1966 [1 Oct., 1965 (2)], No. 43874/66. Headings B5B and B5N. Multilaminate film is made by (I) feeding a plurality of streams of molten thermoplastics resins along independent parallel passageways for a distance sufficient to establish laminar flow; (II) the parallel streams are then brought together in a common passageway so forming a composite resin plug having interfaces between the streams; (III) the plug is then expanded laterally along an axis perpendicular to the direction of flow of the plug and parallel to the interface planes; (IV) the expanded plug is then extruded through a long narrow orifice lying in the plane of the plug. The composite plug may be of rectangular cross-section. The unexpanded composite plug may comprise a primary resin plug of circular cross-section and at least one other resin forming an arcuate portion sheath around not more than one-half of the crosssectional periphery of the primary resin plug. Apparatus is described. The film may be contacted with and adhesively bonded to a web substrate. The film may have one high-slip surface and one low-slip or tacky surface. Slip additives, e.g. fatty amides and antiblock agents, e.g. diatomaceous earth and fine silica may be added to the resin forming the high-slip lamina. The resins used may be polyolefins, e.g. ethylene and propylene polymers and copolymers; for the low-slip and intermediate laminae, copolymers of ethylene or propylene with vinyl acetate, ethyl or methyl acrylate, or methyl methacrylate, may be used. Specification 1,166,459 is referred to.
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