Stretch/shrink film with improved oxygen transmission
AssigneeW. R. Grace & Co.-Conn.
InventorWalter B. Mueller
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Abstract
A multi-layered thermoplastic polyolefin film having an improved combination of physical characteristics is disclosed. In particular, the multi-layered film evidences an improved combination of elongation, oxygen transmission and heat shrinkability. Preferred five layer embodiments of the film comprises (1) a core layer of either a low density polyethylene homopolymer or an ethylene acetate copolymer or a blend of an ethylene vinyl acetate copolymer with a linear low density polyethylene; (2) two adjacent intermediate layers of a very low density polyethylene with a density of less than 0.900 gms/ccm, and (3) two surface layers of an ethylene vinyl acetate copolymer.
Claims13
A multiply film comprising:
- a first interior layer comprising a copolymer of ethylene and vinyl acetate;
- at least one other interior layer comprising a very low density polyethylene having a density below 0.900 grams per cubic centimeter;
- and
- two surface layers comprising a copolymer of ethylene and vinyl acetate;
- wherein the film has an oxygen transmission rate of at least about 15000 cc/m.sup.2 mil 24 hours at standard temperature and pressure.
A five layer film comprising:
- a core layer comprising a copolymer of ethylene and vinyl acetate;
- two intermediate layers each adjacent said core layer, said intermediate layers comprising a very low density polyethylene having a density below 0.900 grams per cubic centimeter;
- and
- two surface layers comprising a copolymer of ethylene and vinyl acetate;
- wherein the film has an oxygen transmission rate of at least about 15000 cc/m.sup.2 mil 24 hours at standard temperature and pressure.
A five layer film comprising:
- a core layer consisting essentially of a copolymer of ethylene and vinyl acetate;
- two intermediate layers each adjacent said core layer, said intermediate layers consisting essentially of a very low density polyethylene having a density below 0.900 grams per cubic centimeter polyethylene;
- and
- two surface layers consisting essentially of a copolymer of ethylene and vinyl acetate;
- wherein the film has an oxygen transmission rate of at least about 15000 cc/m.sup.2 mil 24 hours at standard temperature and pressure.
Dependencies are inferred from the claim text.