Patent US4997690A successfully refreshed from Google Patents.
US4997690A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Irradiated multilayer film for primal meat packaging
Assignee: Viskase Corp
•
Filing: 1989-08-18
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Granted: 1991-03-05
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Expires: 2009-08-18
Abstract
Abstract A heat-shrinkable, multilayer film suitable for use in fabricating bags for packaging primal and sub-primal meat cuts and processed meats. The multilayer film has a first outer layer of a first ethylene-vinyl acetate copolymer, a core layer of a barrier film comprising a polyvinylidene chloride copolymer, and a second outer layer of a second ethylene-vinyl acetate copolymer. The multilayer film is preferably made by co-extrusion of the layers, and then it is biaxially stretched. After biaxial stretching, the multilayer film is irradiated to a dosage level of between 1 megarad and 5 megarads and heat-sealed in the form of a bag. The bag has improved toughness properties and heat-sealing characteristics.
Inventors
- 👤 Stanley Lustig
- 👤 Jeffrey M. Schuetz
- 👤 Stephen J. Vicik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:03
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29; B29C; B29C55/00; B29C55/02; B29C55/023; B65; B65B; B65B25/00; B65B25/06; B65B25/065; B65B25/067; B65D; B65D75/00; B65D75/002; B29C61/00; B29C61/02; B29L; B29L2009/00; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1334; Y10T428/1341
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
64 words
A biaxially stretched multilayer polymeric film comprising first and second layers comprising ethylene vinyl acetate copolymer and a third layer disposed therebetween comprising a vinylidene chloride copolymer, and the entire surfaces of each of the first, second and third layers having been substantially uniformly irradiated to a dosage level of at least about 1 megarad as the sole irradiation treatment of the multilayer film.
Claim 2
Dependent Claim
64 words
A biaxially stretched multilayer polymeric film comprising first and second layers comprising ethylene vinyl acetate copolymer and a third layer disposed therebetween comprising a vinylidene chloride copolymer, and the entire surfaces of each of the first, second and third layers having been substantially uniformly irradiated to a dosage level of at least about 1 megarad as the sole irradiation treatment of the multilayer film.
Claim 3
Dependent Claim
11 words
A bag made from a multilayer film according to claim 1.
Claim 4
Dependent Claim
91 words
A process for making a multilayer biaxially stretched film comprising the steps of: (a) forming a multilayer film having first and second layers comprising ethylene vinyl acetate copolymer and a third layer of vinylidene chloride copolymer disposed between the first and second layers; (b) heating the multilayer film to an elevated temperature appropriate for biaxial stretching, and biaxially stretching it; and (c) subjecting the entire surfaces of each of the first, second and third layers of the biaxially stretched film to irradiation in an amount of at least about 1 megarad.
Claim 5
Dependent Claim
91 words
A process for making a multilayer biaxially stretched film comprising the steps of: (a) forming a multilayer film having first and second layers comprising ethylene vinyl acetate copolymer and a third layer of vinylidene chloride copolymer disposed between the first and second layers; (b) heating the multilayer film to an elevated temperature appropriate for biaxial stretching, and biaxially stretching it; and (c) subjecting the entire surfaces of each of the first, second and third layers of the biaxially stretched film to irradiation in an amount of at least about 1 megarad.
Claim 6
Dependent Claim
14 words
A bag made from a multilayer film produced by the process of claim 3.
Claim 7
Dependent Claim
33 words
A bag according to claim 4, which comprises two confronting layers of said multilayer film peripherally heat sealed one to the other having an opening for insertion of a product into the bag.
Claim 8
Dependent Claim
102 words
A process for making a multilayer biaxially stretched film comprising the steps of: (a) forming a multilayer film having first and second layers comprising ethylene vinyl acetate copolymer and a third layer of vinylidene chloride copolymer disposed between the first and second layers; (b) heating the multilayer film to an elevated temperature appropriate for biaxial stretching, and biaxially stretching it; and (c) subjecting the entire surface of each of the first, second and third layers of the biaxially stretched multilayer film to substantially uniform irradiation in an amount of at least about 1 megarad as the sole irradiation treatment of said film.
Claim 9
Dependent Claim
102 words
A process for making a multilayer biaxially stretched film comprising the steps of: (a) forming a multilayer film having first and second layers comprising ethylene vinyl acetate copolymer and a third layer of vinylidene chloride copolymer disposed between the first and second layers; (b) heating the multilayer film to an elevated temperature appropriate for biaxial stretching, and biaxially stretching it; and (c) subjecting the entire surface of each of the first, second and third layers of the biaxially stretched multilayer film to substantially uniform irradiation in an amount of at least about 1 megarad as the sole irradiation treatment of said film.
Claim 10
Dependent Claim
10 words
A multilayer film made by the process of claim 6.
Claim 11
Dependent Claim
14 words
A bag made from a multilayer film produced by the process of claim 6.
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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) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |