US5397613A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Puncture resistant heat shrinkable film containing narrow molecular weight ethylene alpha olefin
Assignee: Curwood Inc
•
Filing: 1993-07-12
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Granted: 1995-03-14
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Expires: 2013-07-12
Abstract
Abstract A biaxially stretched film with very high heat shrink and puncture resistance properties, formed of low density ethylene alpha olefin copolymer having low melt index, low Mw/Mn, low melting point and low Young's Modulus.
Inventors
- 👤 Paul N. Georgelos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:37
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B32; B32B; B32B27/00; B32B27/32; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/08; C08L23/0807; C08L23/0815; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/08; C08L2205/00; C08L2205/02; C08L2205/03; C08L23/0846; C08L23/0853; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1379; Y10T428/1383; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
114 words
A heat shrinkable, puncture resistant, biaxially stretched thermoplastic film suitable for use in fabricating bags for packaging food articles comprising a polyethylene which is a linear copolymer of ethylene and higher alpha olefin containing from 4 to 8 carbon atoms, having a density between about 0.88 and about 0.905 g/cm 3 , a melt index not exceeding about 1.0 g/10 min, a molecular weight/size distribution ratio Mw/Mn below about 3, a melting point below about 100° C., a Young's Modulus of below about 750 kg/cm 2 , and wherein said film shrinks at least about 50 percent at a temperature of about 90° C. in at least one of the machine and transverse directions.
Claim 2
Dependent Claim
114 words
A heat shrinkable, puncture resistant, biaxially stretched thermoplastic film suitable for use in fabricating bags for packaging food articles comprising a polyethylene which is a linear copolymer of ethylene and higher alpha olefin containing from 4 to 8 carbon atoms, having a density between about 0.88 and about 0.905 g/cm 3 , a melt index not exceeding about 1.0 g/10 min, a molecular weight/size distribution ratio Mw/Mn below about 3, a melting point below about 100° C., a Young's Modulus of below about 750 kg/cm 2 , and wherein said film shrinks at least about 50 percent at a temperature of about 90° C. in at least one of the machine and transverse directions.
Claim 3
Dependent Claim
11 words
A film according to claim 1 wherein said film is monolayer.
Claim 4
Dependent Claim
25 words
A film according to claim 1 wherein said film is multilayer, and the ethylene alpha olefin copolymer comprises at least one layer of said film.
Claim 5
Dependent Claim
46 words
A film according to claim 1 wherein said film is multilayer wherein one layer is an oxygen barrier material as a core with at least one other layer on each side thereof, and the ethylene alpha olefin copolymer comprises at least one of said other layers.
Claim 6
Dependent Claim
17 words
A film according to claim 4 wherein the oxygen barrier-core layer is a copolymer of vinylidene chloride.
Claim 7
Dependent Claim
16 words
A film according to claim 5 wherein the oxygen barrier-core layer is vinylidene chloride-vinyl chloride copolymer.
Claim 8
Dependent Claim
15 words
A film according to claim 5 wherein the oxygen barrier-core layer is vinylidene chloride-methyl acrylate.
Claim 9
Dependent Claim
16 words
A film according to claim 4 wherein the oxygen barrier-core layer is hydrolyzed ethylene vinyl acetate.
Claim 10
Dependent Claim
21 words
A film according to claim 1 wherein the ethylene alpha olefin copolymer is blended with at least one other thermoplastic polymer.
Claim 11
Dependent Claim
17 words
A film according to claim 9 wherein said other thermoplastic polymer is another ethylene alpha olefin copolymer.
Claim 12
Dependent Claim
22 words
A film according to claim 10 wherein said another ethylene alpha olefin copolymer is prepared by a metallocene single site catalyst system.
Claim 13
Dependent Claim
15 words
A film according to claim 9 wherein said other thermoplastic polymer is ethylene vinyl acetate.
Claim 14
Dependent Claim
24 words
A film according to claim 9 wherein the ethylene alpha olefin copolymer is blended with another ethylene alpha olefin copolymer and ethylene vinyl acetate.
Claim 15
Dependent Claim
22 words
A film according to claim 1 wherein said ethylene alpha olefin copolymer has a Vicat softening point not exceeding about 70° C.
Claim 16
Dependent Claim
76 words
A film according to claim 1 wherein the ethylene alpha olefin copolymer is a butene copolymer having density of about 0.88 g/cm 3 , melt index of about 0.5 g/10 min; an Mw value of about 190,000, a Mn value of about 92,600, a melting point of about 67° C., a Young's Modulus of about 400 kg/cm 2 , a dynamic puncture value of about 11.5 cmkg/mil, and a Vicat softening point of about 62° C.
Claim 17
Dependent Claim
9 words
A film according to claim 1 which is crosslinked.
Claim 18
Dependent Claim
11 words
A film according to claim 15 which is crosslinked by irradiation.
Claim 19
Dependent Claim
23 words
A film according to claim 1 which shrinks at least about 55 percent in both the machine and traverse directions at 90° C.
Claim 20
Dependent Claim
73 words
An irradiated film according to claim 15 comprising three layers including a vinylidene chloride-methyl acrylate copolymer oxygen barrier-core layer and an outer layer on each side of said barrier-core layer comprising a blend of between about 65 and 75% of said ethylene alpha olefin copolymer and between about 20 and 30% ethylene vinyl acetate, and said film shrinks at least about 55 percent in both the machine and transverse directions at 90° C.
Claim 21
Dependent Claim
24 words
A film according to claim 1 wherein ethylene alpha olefin copolymer has a weight average molecular weight Mw of at least about 180,000 g/mole.
Claim 22
Dependent Claim
24 words
A film according to claim 1 wherein the ethylene alpha olefin copolymer has a number average molecular weight of at least about 83,000 g/mole.
Claim 23
Dependent Claim
16 words
A film according to claim 2 having dynamic puncture strength of at least about 10 cmkg/mil.
Claim 24
Dependent Claim
16 words
A film according to claim 19 having dynamic puncture strength of at least about 3 cmkg/mil.
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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) | 1998-03-13 | 1998-09-12 | 1999-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-13 | 2002-09-12 | 2003-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-13 | 2006-09-12 | 2007-03-14 | $7700.00 | Window Closed / Lapsed |