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US 4,640,856 AGranted
Multi-layer packaging film and receptacles made therefrom
AssigneeW. R. Grace & Co., Cryovac Div.
InventorsDaniel J. Ferguson, Henry G. Schirmer, Walter B. Mueller
Life of this patent
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Abstract
Improved shrink, toughness and barrier properties are achieved by a multi-layer, thermoplastic, shrink film having a substrate layer of very low density polyethylene and a gas barrier layer of vinylidene chloride copolymer or ethylene-vinyl-alcohol. The film is particularly useful for making bags for packaging large cuts of fresh red meat.
Claims18
A multi-layer, thermoplastic barrier film having at least three layers comprising:
- (a) a layer consisting essentially of very low density polyethylene having a density of less than 0.910 gms/cc;
- (b) a barrier layer comprising a material selected from the group consisting of:
- (1) copolymers of vinylidene chloride and (2) hydrolyzed ethylene-vinyl acetate copolymers;
- (c) a thermoplastic polymeric layer, said layer being on the side of the barrier layer opposite to that of layer (a);
- and,
- (d) the shrinkage of layer (a) controlling the shrinkage of the entire multi-layer barrier film, said multi-layer film having been oriented and rendered heat shrinkable at a temperature below 100.degree. C. (212.degree. F.), said orientation temperature being about 40.degree. F. or more below the melt temperature of said very low density polyethylene.
3 more elements
A multi-layer thermoplastic barrier film comprising:
- (a) at least one layer consisting essentially of a very low density polyethylene having a density of less than 0.910 gms/cc and a melt temperature of about 244.degree. F., said layer or layers of very low density polyethylene comprising at least 65% of the thickness of said multi-layer film;
- and, said very low density polyethylene layer being orientable below the boiling point of water;
- (b) a layer comprising a polymeric barrier material;
- and,
- (c) a thermoplastic polymeric layer comprising a material selected from the group consisting of:
- (1) ethylene polymers and copolymers, and (2) blends of polymers or copolymers selected from group (1).
3 more elements
Dependencies are inferred from the claim text.