US4833024A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low shrink energy films
Assignee: Cryovac LLC
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Filing: 1987-10-16
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Granted: 1989-05-23
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Expires: 2007-10-16
Abstract
Abstract The multilayer shrink film of the present invention provides very low shrink tension approximating some PVC films, while providing relatively high free shrink characteristics and relatively low shrink temperatures. The preferred film has five layers including a core layer comprising a linear low density polyethylene or ethylene propylene copolymer, two outer layers comprising a polymeric material selected from the group consisting of linear low density polyethylene and ethylene propylene copolymer, and two intermediate layers comprising a polymeric material or blend of materials having a melting point of less than 100° C. Suitable materials include ethylene vinyl acetate copolymer, a blend of ethylene vinyl acetate copolymer and very low density polyethylene, ethylene butyl acrylate copolymer, and a blend of ethylene vinyl acetate copolymer and ethylene butyl acrylate copolymer.
Inventors
- 👤 Walter B. Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:41
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29; B29C; B29C61/00; B29C61/06; B29C61/0608; B29C61/0616; B32B27/30; B32B27/306; B32B27/32; B32B2553/00; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10S428/913; Y10T; Y10T428/00; Y10T428/28; Y10T428/2813; Y10T428/2817; Y10T428/2826; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/3192
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
135 words
A multilayer shrink film comprising: (a) a core layer comprising a linear low density polyethylene or ethylene propylene copolymer; (b) two outer layers comprising a polymeric material selected from the group consisting of linear low density polyethylene and ethylene propylene copolymer; and (c) two intermediate layers comprising a polymeric material or blend of materials having a melting point of less than about 100° C.; wherein said film has an average machine direction shrink tension at 205° F. of no more than about 250 pounds per square inch, and an average transverse direction shrink tension at 205° F. of no more than about 300 pounds per square inch, said shrink tension values as measured by ASTM D 2838; and wherein the intermediate layers comprise about 60% to 90% of the total thickness of the multilayer film.
Claim 2
Dependent Claim
135 words
A multilayer shrink film comprising: (a) a core layer comprising a linear low density polyethylene or ethylene propylene copolymer; (b) two outer layers comprising a polymeric material selected from the group consisting of linear low density polyethylene and ethylene propylene copolymer; and (c) two intermediate layers comprising a polymeric material or blend of materials having a melting point of less than about 100° C.; wherein said film has an average machine direction shrink tension at 205° F. of no more than about 250 pounds per square inch, and an average transverse direction shrink tension at 205° F. of no more than about 300 pounds per square inch, said shrink tension values as measured by ASTM D 2838; and wherein the intermediate layers comprise about 60% to 90% of the total thickness of the multilayer film.
Claim 3
Dependent Claim
26 words
A multilayer shrink film according to claim 1 wherein the two outer layers are each derived from a blend of two linear low density polyethylene resins.
Claim 4
Dependent Claim
60 words
A multilayer shrink film according to claim 1 wherein the two intermediate layers comprise a polymeric material selected from the group consisting of: (a) ethylene vinyl acetate copolymer; (b) a blend of ethylene vinyl acetate copolymer and very low density polyethylene; (c) ethylene butyl acrylate copolymer; and (d) a blend of ethylene vinyl acetate copolymer and ethylene butyl acrylate copolymer.
Claim 5
Dependent Claim
31 words
A multilayer shrink film according to claim 3 wherein the two intermediate layers comprise an ethylene vinyl acetate copolymer having between about 8% and about 30% by weight of vinyl acetate.
Claim 6
Dependent Claim
14 words
A multilayer shrink film according to claim 1 wherein the film layers are cross-linked.
Claim 7
Dependent Claim
22 words
A multilayer shrink film according to claim 1 wherein the shrink tension of the film is substantially controlled by the intermediate layers.
Claim 8
Dependent Claim
124 words
A multilayer shrink film comprising: (a) a core layer comprising a linear low density polyethylene or ethylene propylene copolymer; (b) two outer layers comprising a polymeric material selected from the group consisting of linear low density polyethylene and ethylene propylene copolymer; (c) two intermediate layers comprising a polymeric material or blend of materials having a melting point of less than about 100° C.; wherein said film has an average machine direction free shrink at 205° F. of at least about 30% and an average transverse direction free shrink at 205° F. of at least about 30%, said free shrink values as measured by ASTM D 2732; and wherein the intermediate layers comprise about 60% to 90% of the total thickness of the multilayer film.
Claim 9
Dependent Claim
124 words
A multilayer shrink film comprising: (a) a core layer comprising a linear low density polyethylene or ethylene propylene copolymer; (b) two outer layers comprising a polymeric material selected from the group consisting of linear low density polyethylene and ethylene propylene copolymer; (c) two intermediate layers comprising a polymeric material or blend of materials having a melting point of less than about 100° C.; wherein said film has an average machine direction free shrink at 205° F. of at least about 30% and an average transverse direction free shrink at 205° F. of at least about 30%, said free shrink values as measured by ASTM D 2732; and wherein the intermediate layers comprise about 60% to 90% of the total thickness of the multilayer film.
Claim 10
Dependent Claim
24 words
A multilayer shrink film according to claim 7 wherein the two outer layers each comprise a blend of two linear low density poly-ethylene resins.
Claim 11
Dependent Claim
60 words
A multilayer shrink film according to claim 7 wherein the two intermediate layers comprise a polymeric material selected from the group consisting of: (a) ethylene vinyl acetate copolymer; (b) a blend of ethylene vinyl acetate copolymer and very low density polyethylene; (c) ethylene butyl acrylate copolymer; and (d) a blend of ethylene vinyl acetate copolymer and ethylene butyl acrylate copolymer.
Claim 12
Dependent Claim
31 words
A multilayer shrink film according to claim 9 wherein the two intermediate layers comprise an ethylene vinyl acetate copolymer having between about 8% and about 30% by weight of vinyl acetate.
Claim 13
Dependent Claim
14 words
A multilayer shrink film according to claim 7 wherein the film layers are cross-linked.
Claim 14
Dependent Claim
22 words
A multilayer shrink film according to claim 7 wherein the free shrink of the film is substantially controlled by the intermediate layers.
Claim 15
Dependent Claim
26 words
A multilayer shrink film according to claim 1 wherein the intermediate layers include between about 1% and 2% mineral oil by weight of the intermediate layer.
Claim 16
Dependent Claim
26 words
A multilayer shrink film according to claim 7 wherein the intermediate layers include between about 1% and 2% mineral oil by weight of the intermediate layer.
References Cited (Backward Citations)
US3595735A
Cited
US4194039A
Cited
US4188443A
Cited
US4399180A
Cited
US4352849A
Cited
US4399173A
Cited
US4532189A
Cited
US4551380A
Cited
US4590124A
Cited
US4514465A
Cited
EP0229715A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-22 | 1992-11-21 | 1993-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-22 | 1996-11-21 | 1997-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-22 | 2000-11-21 | 2001-05-23 | $7700.00 | Window Closed / Lapsed |