US4501779A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat resistant heat shrinkable film
Assignee: Pechiney Plastic Packaging Inc
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Filing: 1981-10-05
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Granted: 1985-02-26
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Expires: 2001-10-05
Abstract
Abstract A three layer heat shrinkable film is disclosed, along with preferred process for making it. The film comprises a first heat sealable layer of an ionomer, a second layer of a vinylidene chloride copolymer, and a third layer of a blend of an ionomer and an EVA copolymer. The EVA content is no greater than 20% of the blend by weight, and the vinyl acetate content is at least 4.5% of the blend by weight. In the preferred process, a three layer tape is coextruded and cooled, and reheated to 197 DEG -203 DEG F., and oriented in a conventional double bubble process.
Inventors
- 👤 Joseph C. Hsu
- 👤 Donald W. Vought
- 👤 George H. Walbrun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:36
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/30; B32B27/304; B32B27/306; B32B2250/00; B32B2250/24; B32B2270/00; B32B2307/00; B32B2307/30; B32B2307/31; B32B2307/50; B32B2307/514; B32B2307/70; B32B2307/732; B32B2307/734; B32B2307/736; B32B2327/00; B32B2331/00; B32B2331/04; B32B2439/00; B32B2439/40; B32B2439/70; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1328; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/28; Y10T428/2813; Y10T428/2817; Y10T428/2826; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/3192
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
74 words
A heat shrinkable bag made from a three layer tubular film, the film comprising: (a) a first heat sealable layer of ionomer; (b) a second layer of a vinylidene chloride copolymer; and (c) a third layer of a blend of an ionomer and an EVA copolymer, wherein the EVA content is no greater than 20% of the blend by weight, and the vinyl acetate content is at least 4.5% of the blend by weight.
Claim 2
Dependent Claim
74 words
A heat shrinkable bag made from a three layer tubular film, the film comprising: (a) a first heat sealable layer of ionomer; (b) a second layer of a vinylidene chloride copolymer; and (c) a third layer of a blend of an ionomer and an EVA copolymer, wherein the EVA content is no greater than 20% of the blend by weight, and the vinyl acetate content is at least 4.5% of the blend by weight.
Claim 3
Dependent Claim
40 words
A heat shrinkable bag as in claim 1, wherein the EVA content of the film is between 15% and 20% of the blend by weight and the vinyl acetate content is 22% to 33% of the EVA copolymer by weight.
Claim 4
Dependent Claim
69 words
A heat shrinkable oriented three layer film, comprising: (a) a first heat sealable layer of an ionomer; (b) a second layer of a vinylidene chloride copolymer; and (c) a third layer of a blend of an ionomer and an EVA copolymer, wherein the EVA content is no greater than 20% of the blend by weight, and the vinyl acetate content is at least 4.5% of the blend by weight.
Claim 5
Dependent Claim
69 words
A heat shrinkable oriented three layer film, comprising: (a) a first heat sealable layer of an ionomer; (b) a second layer of a vinylidene chloride copolymer; and (c) a third layer of a blend of an ionomer and an EVA copolymer, wherein the EVA content is no greater than 20% of the blend by weight, and the vinyl acetate content is at least 4.5% of the blend by weight.
Claim 6
Dependent Claim
36 words
A film as in claim 3 wherein the EVA content is between about 15% and 20% of the blend by weight and the vinyl acetate content is 22% to 33% of the EVA copolymer by weight.
References Cited (Backward Citations)
US4161562A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-02-26 | 1988-08-27 | 1989-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-26 | 1992-08-27 | 1993-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-26 | 1996-08-27 | 1997-02-26 | $7700.00 | Window Closed / Lapsed |