US4469742A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pasteurizable, cook-in shrink film
Assignee: Cryovac LLC
•
Filing: 1983-01-31
•
Granted: 1984-09-04
•
Expires: 2003-01-31
Abstract
Abstract A pasteurizable and/or cook-in shrink film is provided that includes a first or sealing layer of a nonlipophillic polymeric material having a softening point greater than that of the following shrink layer; a second or shrink controlling layer, melt bonded to the first layer, of an ethylene homopolymer or copolymer; a third or adhesive layer, melt bonded to the second layer, of a chemically modified polyethylene being irradiatively cross-linkable and having functional groups with a relatively strong affinity for the following barrier layer; a fourth or barrier layer, melt bonded to the third layer, of a hydrolyzed ethylene-vinyl acetate copolymer; a fifth or adhesive layer as in said third layer, melt bonded to the fourth layer; and a sixth or abuse layer, melt bonded to the fifth layer. An associated method for making the film is also provided that includes full coextrusion and selective irradiation and orientation.
Inventors
- 👤 Timothy T. Oberle
- 👤 Henry G. Schirmer
- 👤 Norman D. Bornstein
- 👤 Johnnie J. Walters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:54
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29; B29C; B29C48/00; B29C48/16; B29C48/18; B29C48/185; B32B27/16; B32B27/30; B32B27/306; B32B27/32; B32B7/00; B32B7/04; B32B7/12; B65; B65D; B65D81/00; B65D81/34; B65D81/3415; B65D81/3423; B29C48/03; B29C48/09; B29C48/10; B32B2305/00; B32B2305/72; B32B2307/00; B32B2307/50; B32B2307/514; B32B2307/518; B32B2310/00; B32B2310/08; B32B2310/0875; B32B2310/0881; B32B2323/00; B32B2323/04; B32B2323/043; B32B2553/00; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/13; Y10T428/1328; Y10T428/1334; Y10T428/1341; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/28; Y10T428/2813; Y10T428/2817; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31928
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
224 words
A pasteurizable and/or cook-in shrink film, comprising: (a) a first or sealing layer which comprises a nonlipophillic polymeric material having a softening point greater than that of the following shrink layer; (b) a second or shrink layer, melt bonded to said first layer, which comprises a cross-linked ethylene homopolymer or copolymer, further provided that the thickness of said second layer is sufficient such that the shrink temperature of the entire multilayer film, when oriented, is substantially controlled by the shrink temperature of said second layer; (c) a third or adhesive layer, melt bonded to said second layer, which comprises a chemically modified cross-linked polyethylene and having functional groups with a relatively strong affinity for the following barrier layer; (d) a fourth or barrier layer, melt bonded to said third layer, which comprises a hydrolyzed cross-linked ethylene-vinyl acetate copolymer; (e) a fifth or adhesive layer of substantially the same composition as said third layer, melt bonded to said fourth layer; and (f) a sixth or abuse layer comprising a cross-linked polymer, melt bonded to said fifth layer; (g) wherein all of said layers of said film are irradiatively cross-linked to an extent corresponding to an irradiation dosage sufficient to increase the resistance of the film layers to delamination under cook-in or pasteurizing conditions but which permits the first layer to function as a sealing layer.
Claim 2
Dependent Claim
224 words
A pasteurizable and/or cook-in shrink film, comprising: (a) a first or sealing layer which comprises a nonlipophillic polymeric material having a softening point greater than that of the following shrink layer; (b) a second or shrink layer, melt bonded to said first layer, which comprises a cross-linked ethylene homopolymer or copolymer, further provided that the thickness of said second layer is sufficient such that the shrink temperature of the entire multilayer film, when oriented, is substantially controlled by the shrink temperature of said second layer; (c) a third or adhesive layer, melt bonded to said second layer, which comprises a chemically modified cross-linked polyethylene and having functional groups with a relatively strong affinity for the following barrier layer; (d) a fourth or barrier layer, melt bonded to said third layer, which comprises a hydrolyzed cross-linked ethylene-vinyl acetate copolymer; (e) a fifth or adhesive layer of substantially the same composition as said third layer, melt bonded to said fourth layer; and (f) a sixth or abuse layer comprising a cross-linked polymer, melt bonded to said fifth layer; (g) wherein all of said layers of said film are irradiatively cross-linked to an extent corresponding to an irradiation dosage sufficient to increase the resistance of the film layers to delamination under cook-in or pasteurizing conditions but which permits the first layer to function as a sealing layer.
Claim 3
Dependent Claim
22 words
The film of claim 1 wherein said film is irradiatively cross-linked to an extent corresponding to a dosage of about 3-12 MR.
Claim 4
Dependent Claim
22 words
The film of claim 2 wherein said film is irradiatively cross-linked to an extent corresponding to a dosage of about 6-8 MR.
Claim 5
Dependent Claim
10 words
The film of claim 1 wherein said film is oriented.
Claim 6
Dependent Claim
26 words
The film of claim 4 wherein said film is biaxially oriented to an extent corresponding to a biaxial free shrinkage at 185° F. of about 30-55%.
Claim 7
Dependent Claim
24 words
The film of claim 4 wherein said film prior to orientation has multilayer dimensions of about 2-6/ 4-8/ 0.25-1/ 0.75-2/ 0.25-1/ 3-8 mils, respectively.
Claim 8
Dependent Claim
23 words
The film of claim 6 wherein said first layer comprises a propylene-ethylene random copolymer having an ethylene content of about 1-6% by weight.
Claim 9
Dependent Claim
46 words
The film of claim 1 wherein said first layer comprises an ionomer characterized as a metal salt neutralized copolymer of ethylene and acrylic acid or methacrylic acid, and said second layer comprises an ethylene-vinyl acetate copolymer having a vinyl acetate content of about 9-12% by weight.
Claim 10
Dependent Claim
30 words
The film of claim 1 wherein said second layer comprises an ethylene-vinyl acetate copolymer having a vinyl acetate content of about 12% or less by weight, or low density polyethylene.
Claim 11
Dependent Claim
54 words
The film of claim 1 wherein said third layer comprises a blend of a graft copolymer of a high density polyethylene or ethylene-vinyl acetate copolymer and at least one unsaturated fused ring carboxylic acid anhydride with polyethylene, a copolymer of ethylene and an alpha-olefin, or both; or a thallic acid modified low density polyethylene.
Claim 12
Dependent Claim
15 words
The film of claim 1 wherein said sixth layer comprises an ethylene homopolyer or copolymer.
Claim 13
Dependent Claim
24 words
The film of claim 11 wherein said sixth layer comprises and ethylene-vinyl acetate copolymer having a vinyl acetate content of about 5-12% by weight.
Claim 14
Dependent Claim
17 words
The film of claim 1 wherein said sixth layer comprises the same material as said first layer.
References Cited (Backward Citations)
US3595740A
Cited
US3741253A
Cited
US4087587A
Cited
US4064296A
Cited
US4087558A
Cited
US4276330A
Cited
US4233367A
Cited
US4370388A
Cited
US4352702A
Cited
US4391862A
Cited
US4407873A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-04 | 1988-03-05 | 1988-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-04 | 1992-03-05 | 1992-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-04 | 1996-03-05 | 1996-09-04 | $7700.00 | Window Closed / Lapsed |