US4965135A
Expired / Lapsed
US
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Multilayer film with dead fold and twistability characteristics
Assignee: DowBrands Inc
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Filing: 1987-12-14
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Granted: 1990-10-23
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Expires: 2007-12-14
Abstract
Abstract A multilayer film is provided in the form of an extruded sheet for food wrapping and cooking procedures. The film is made up of alternating layers of a first generally ductile material and a second generally brittle material. Upon wrapping a food item or container, the film exhibits dead fold and/or twistability characteristics. In one embodiment, the materials of the film are chosen to have softening points above about 450 degrees F. so that the film can be used in conventional ovens.
Inventors
- 👤 Jang-hi Im
- 👤 Rexford A. Maugans
- 👤 David R. Kiesel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:18
CPC Classifications
B; B32; B32B; B32B7/00; B32B7/02; B32B7/022; B32B27/00; B32B27/30; B32B27/302; B32B27/304; B32B27/32; B32B27/34; B32B27/36; B32B27/365; B32B37/00; B32B37/14; B32B37/15; B32B37/153; B32B2250/00; B32B2250/05; B32B2250/42; B32B2307/00; B32B2307/40; B32B2307/412; B32B2323/00; B32B2323/04; B32B2323/046; B32B2323/10; B32B2325/00; B32B2327/00; B32B2327/06; B32B2377/00; B32B2439/00; B32B2439/70; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1334; Y10T428/1341; Y10T428/31504; Y10T428/31507; Y10T428/31725; Y10T428/31739; Y10T428/31743; Y10T428/31746; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31917; Y10T428/3192; Y10T428/31928
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
104 words
A multilayer film comprising at least 25 alternating layers of a first material and a second material, said first material comprising a ductile polymeric material having at least one distinct yield point, and wherein said first material is selected from the group consisting of polycarbonate, polyolefin, and nylon, said second material comprising a brittle polymeric material capable of fracturing upon the application of tensile stress and wherein said second material is selected from the group consisting of polystyrene, styrene-acrylonitrile copolymer, and poly (vinyl chloride), and the number of alternating layers being sufficient to cause said film to exhibit dead fold, creasing, and/or twistability characteristics.
Claim 2
Dependent Claim
104 words
A multilayer film comprising at least 25 alternating layers of a first material and a second material, said first material comprising a ductile polymeric material having at least one distinct yield point, and wherein said first material is selected from the group consisting of polycarbonate, polyolefin, and nylon, said second material comprising a brittle polymeric material capable of fracturing upon the application of tensile stress and wherein said second material is selected from the group consisting of polystyrene, styrene-acrylonitrile copolymer, and poly (vinyl chloride), and the number of alternating layers being sufficient to cause said film to exhibit dead fold, creasing, and/or twistability characteristics.
Claim 3
Dependent Claim
25 words
The film of claim 1 wherein said polyolefin is selected from the group consisting of linear low density polyethylene, low density polyethylene, polypropylene, and polybutylene.
Claim 4
Dependent Claim
10 words
The film of claim 1 wherein said film is coextruded.
Claim 5
Dependent Claim
14 words
The film of claim 1 wherein alternating layers of said film are laminated together.
Claim 6
Dependent Claim
11 words
The film of claim 1 wherein said film is generally transparent.
Claim 7
Dependent Claim
115 words
A multilayer film having a softening point of at least about 450 degrees F, said film comprising at least 25 alternating layers of a first material and a second material, said first material comprising a ductile polymeric material having at least one distinct yield point and wherein said first material is selected from the group consisting of polycarbonate and nylon, said second material comprising a brittle polymeric material capable of fracturing upon the application of tensile stress and wherein said second material is selected from the group consisting of polystyrene, styrene-acrylonitrile copolymer, and poly (vinyl chloride), and the number of alternating layers being sufficient to cause said film to exhibit dead fold and/or twistability characteristics.
Claim 8
Dependent Claim
115 words
A multilayer film having a softening point of at least about 450 degrees F, said film comprising at least 25 alternating layers of a first material and a second material, said first material comprising a ductile polymeric material having at least one distinct yield point and wherein said first material is selected from the group consisting of polycarbonate and nylon, said second material comprising a brittle polymeric material capable of fracturing upon the application of tensile stress and wherein said second material is selected from the group consisting of polystyrene, styrene-acrylonitrile copolymer, and poly (vinyl chloride), and the number of alternating layers being sufficient to cause said film to exhibit dead fold and/or twistability characteristics.
Claim 9
Dependent Claim
10 words
The film of claim 6 wherein said film is coextruded.
Claim 10
Dependent Claim
14 words
The film of claim 6 wherein alternating layers of said film are laminated together.
Claim 11
Dependent Claim
11 words
The film of claim 6 wherein said film is generally transparent.
Claim 12
Dependent Claim
20 words
The film of claim 1 in which said first material is nylon and said second material is general purpose polystyrene.
Claim 13
Dependent Claim
36 words
The film of claim 1 in which from about 50 to about 75% by volume of said film is nylon and from about 50 to about 25% by volume of said film is general purpose polystyrene.
Claim 14
Dependent Claim
23 words
The film of claim 1 in which said first material is linear low density polyethylene and said second material is general purpose polystyrene.
Claim 15
Dependent Claim
50 words
A multilayer film consisting essentially of at least 25 alternating layers of a first generally ductile polymeric material selected from the group consisting of nylon and linear low density polyethylene and a second generally brittle polymeric material comprising general purpose polystyrene capable of fracturing upon the application of tensile stress.
Claim 16
Dependent Claim
50 words
A multilayer film consisting essentially of at least 25 alternating layers of a first generally ductile polymeric material selected from the group consisting of nylon and linear low density polyethylene and a second generally brittle polymeric material comprising general purpose polystyrene capable of fracturing upon the application of tensile stress.
Claim 17
Dependent Claim
13 words
The multilayer film of claim 13 in which said first material is nylon.
Claim 18
Dependent Claim
37 words
The multilayer film of claim 14 in which from about 50 to about 75% by volume of said film is nylon and from about 50 to about 25% by volume of said film is general purpose polystyrene.
Claim 19
Dependent Claim
16 words
The multilayer film of claim 13 in which said first material is linear low density polyethylene.
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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) | 1993-10-22 | 1994-04-23 | 1994-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-22 | 1998-04-23 | 1998-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-22 | 2002-04-23 | 2002-10-23 | $7700.00 | Window Closed / Lapsed |