COEXTRUDED MULTILAYER FILMS FOR FLUID-CONTAINING STERILIZED VESSELS Russian patent published in 2003 - IPC

FIELD: flexible transparent films, particularly, for manufacture of vessels for solutions for intravenous injection with use of methods F-F-S (formation-filling-sealing). SUBSTANCE: film has external and internal layers made of heterogeneous compositions. External layer is selected from group including polypropylene homopolymer, copolymer of ethylene and propylene, mixture of high-density polyethylene and block copolymer of propylene and ethylene. Internal layer is selected from group consisting of copolymer of ethylene and alpha-olefin, and copolymers of ethylene and alpha-olefin mixed with polyethylene of low density. External layer is joined with internal layer by complex intermediate layer containing several sublayers forming upper part B1, core B2 and lower part B3. Upper and lower parts of intermediate layer correspondingly have gradients of content of combined ethylene monomeric links and temperature of softening. Produced films meet higher requirements for their strength possess maximum useful characteristics, particularly, optimal combination of suck properties as adhesion between terminal layers (A) and (C), compatibility, transparency, softness, shock resistance in falling, strong sealing seam, absent liberation of products of decomposition into solution, and others. EFFECT: higher efficiency of use. 29 cl, 3 dwg, 1 tbl, 5 ex