US 4,886,690 AGranted

Peelable barrier film for vacuum skin packages and the like

AssigneeW. R. Grace & Co.

InventorsKent A. Davis, Solomon Bekele, Henry W. Stockley

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Abstract

A vacuum skin package for packaging fresh red meat and like articles is produced by using a composite, multilayer, oxygen barrier, vacuum skin packaging forming film in which the barrier layer can be manually separated from the non-barrier, oxygen permeable layer. After the vaccum skin package is formed to enclose a fresh red meat product in a vacuum the meat will have a purplish color. Then, after storage, the barrier layer can be removed so that the remaining permeable film can admit oxygen to impart the desirable red bloom to the fresh meat. Of importance is the "tear through" feature of the permeable inner layer which has a greater bond strength to the tray than internal strength or layer-to-layer bond strength so that a tab may be torn loose at a score line and then the barrier layer may be readily delaminated and peeled from the permeable layer.

Claims12

Dependent claims

A forming web for vacuum skin packaging and the like which web is separable into permeable and impermeable films comprising:

(A) a coextruded, multi-layer composite film web comprising a gas permeable film and a gas impermeable film which can be manually delaminated from each other;
(1) said gas permeable film having a plurality of layers including:
(a) a heat sealable layer selected from the group consisting of ethylene polymers, copolymers, and blends thereof;
and,
(b) a layer comprising a linear ethylene/alpha-olefin copolymer having a density of less than 0.915 gms/cm.sup.3 and,
(2) said multi-layer gas impermeable film comprising a plurality of layers including:
(a) a barrier layer comprising a material selected from the group consisting of hydrolyzed ethylene vinyl acetate copolymers (EVOH) and vinylidene chloride copolymers or terpolymers (PVDC), said barrier layer being immediately adjacent to and in contact with said linear ethylene/alpha-olefin copolymer (1) (b) so that when delamination occurs the barrier layer will become a first surface layer;
and,
(b) an outer or second surface layer of polymeric material;
and,
(B) said heat sealable layer being capable to sealing to a polymeric surface with a bond strength greater than the force required to rupture and subsequently delaminate said permeable layer from said impermeable layer.

8 more elements

A composite, thermoformable web for vacuum skin packages and the like comprising:

(a) a sealant layer having a thickness in the range of about 0.20 to 0.60 mils and comprising a polymeric material selected from the group consisting of linear ethylene/alpha-olefin copolymers having a density of about 0.910 g/cc or less and ethylene/vinyl-acetate content in the range of 4% to 12% by weight, said sealant layer being one surface layer;
(b) a core layer having a thickness in the range of about 1.75 to 2.50 mils and comprising a polymeric material selected from the group consisting of linear ethylene/alpha-olefin copolymers having a density of about 0.910 g/cc or less (VLDPE) and ethylene/vinyl-acetate copolymers having a vinyl acetate content in the range of 18% to 28% by weight, said core layer being adjacent to said sealant layer;
(c) an optical layer having a thickness in the range of about 0.10 to 0.20 mils and comprising a polymeric material selected from the group consisting of VLDPE resins, said optical layer being adjacent said core layer,
(d) a first EVOH layer having a thickness in the order of 0.20 mils and being adjacent to said optical layers and being manually peelable therefrom along with layers (e) through (i);
(e) a first tie layer comprising a blend of about 40% of weight of an LDPE based adhesive with about 60% by weight of HDPE, said tie layer having a thickness of approximately 20 mils and being adjacent said first EVOH layer;
(f) a second EVOH layer having a thickness of approximately 0.20 mils and being adjacent said first tie layer;
(g) a second tie layer having a thickness of approximately 0.20 mil and comprising the same material as the first tie layer, said second tie layer being adjacent said second EVOH layer;
(h) a layer comprising ethylene/vinyl-acetate copolymer (EVA) having a vinyl acetate content of approximately 18% by weight, said layer being adjacent said second tie layer and being approximately 1.5 mils in thickness;
and
(i) a layer comprising HDPE adjacent said EVA layer, said layer being approximately 0.20 mils thick and being an outside layer.

7 more elements

Dependencies are inferred from the claim text.