US4640856A
Expired / Lapsed
US
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Multi-layer packaging film and receptacles made therefrom
Assignee: Cryovac LLC
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Filing: 1985-04-29
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Granted: 1987-02-03
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Expires: 2005-04-29
Abstract
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.
Inventors
- 👤 Daniel J. Ferguson
- 👤 Henry G. Schirmer
- 👤 Walter B. Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:11
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/30; B32B27/32; B32B7/00; B32B7/04; B32B7/12; B32B2305/00; B32B2305/72; B32B2307/00; B32B2307/50; B32B2307/58; B32B2307/581; B32B2307/582; B32B2307/5825; B32B2307/70; B32B2307/726; B32B2307/7265; B32B2307/732; B32B2307/734; B32B2307/736; B32B2310/00; B32B2310/08; B32B2310/0806; B32B2323/00; B32B2323/04; B32B2323/046; B32B2439/00; B32B2439/70; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/13; Y10T428/1328; Y10T428/1334; Y10T428/1341; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/3192; Y10T428/31928
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
127 words
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° C. (212° F.), said orientation temperature being about 40° F. or more below the melt temperature of said very low density polyethylene.
Claim 2
Dependent Claim
127 words
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° C. (212° F.), said orientation temperature being about 40° F. or more below the melt temperature of said very low density polyethylene.
Claim 3
Dependent Claim
37 words
The film of claim 1 wherein the thermoplastic polymer of layer (c) comprises a material selected from the group consisting of: (1) ethylene polymers and copolymers, and (2) blends of polymers or copolymers selected from group (1).
Claim 4
Dependent Claim
13 words
The film of claim 2 wherein layer (c) comprises an ethylene-vinyl acetate copolymer.
Claim 5
Dependent Claim
14 words
The film of claim 2 wherein layer (c) comprises a very low density polyethylene.
Claim 6
Dependent Claim
14 words
The film of claim 2 wherein layer (c) comprises a linear low density polyethylene.
Claim 7
Dependent Claim
23 words
The film of claim 2 wherein layer (c) comprises a blend of a linear low density polyethylene and a very low density polyethylene.
Claim 8
Dependent Claim
27 words
The film of claim 1 wherein said film is in the form of a seamless tube with layer (a) being the face of the inner tube wall.
Claim 9
Dependent Claim
14 words
The film of claim 1 wherein the material of layer 1 has been cross-linked.
Claim 10
Dependent Claim
16 words
The film of claim 8 wherein the material of layer 1 has been cross-linked by radiation.
Claim 11
Dependent Claim
43 words
A bag formed from tubular film according to claim 7 wherein the bottom of the bag is formed by a transverse seal across the flattened tube and the mouth is formed by severing the tube at a pre-selected distance from said transverse seal.
Claim 12
Dependent Claim
109 words
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° 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).
Claim 13
Dependent Claim
109 words
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° 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).
Claim 14
Dependent Claim
13 words
The film of claim 11 wherein the very low density polyethylene is cross-linked.
Claim 15
Dependent Claim
12 words
The film of claim 11 wherein the thermoplastic barrier material is cross-linked.
Claim 16
Dependent Claim
24 words
The multi-layer film of claim 11 wherein an adhesive layer is interposed between the barrier layer and the layer of very low density polyethylene.
Claim 17
Dependent Claim
44 words
The multi-layer film of claim 11 wherein said film comprises at least five layers in which the center layer comprises a barrier material, the layers on each side of the barrier layer comprise an adhesive, and the surface layers comprise very low density polyethylene.
Claim 18
Dependent Claim
13 words
The film of claim 15 wherein the film has been formed by coextrusion.
Claim 19
Dependent Claim
22 words
The film of claim 15 wherein at least one layer is a cross-linked substrate layer upon which subsequent have been extrusion coated.
Claim 20
Dependent Claim
33 words
A side-sealed bag formed from the film of claim 11, said film being folded so that the fold forms the bottom of the bag and side seals close the side of the bag.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-02 | 1990-08-04 | 1991-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-02 | 1994-08-04 | 1995-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-02 | 1998-08-04 | 1999-02-03 | $7700.00 | Window Closed / Lapsed |