US5152946A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Producing low shrink packaging film
Assignee: Applied Extrusion Technologies Inc
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Filing: 1991-01-30
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Granted: 1992-10-06
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Expires: 2011-01-30
Abstract
Abstract Biaxially oriented film is post-treated by an annealing process in a limited temperature range of 45 DEG C. to 120 DEG C. for various time periods based on the temperature for annealing in order to produce a film having less than a 0.2% shrinkage in the machine direction as measured at 51.7 DEG C. for 24 hours. This film has a wide range of uses, such as overwrapping film.
Inventors
- 👤 Paul C. Gillette
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:27
CPC Classifications
B; B29; B29C; B29C71/00; B29C71/02; B29C2071/022; B29C55/00; B29K; B29K2995/00; B29K2995/0037; B29K2995/0049; B29K2995/005; B29K2995/0053
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
74 words
A process for increasing stability of formed and biaxially oriented polyolefin film comprising heat treating said formed and biaxially oriented polyolefin film under unconstrained conditions within a temperature range of from about 45° C. to about 120° C. over a corresponding time period of from at least about 48 hours to not more than about 2 seconds to obtain a film having shrink properties of less than about 0.2% measured in the machine direction.
Claim 2
Dependent Claim
74 words
A process for increasing stability of formed and biaxially oriented polyolefin film comprising heat treating said formed and biaxially oriented polyolefin film under unconstrained conditions within a temperature range of from about 45° C. to about 120° C. over a corresponding time period of from at least about 48 hours to not more than about 2 seconds to obtain a film having shrink properties of less than about 0.2% measured in the machine direction.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein the polyolefin film is an alpha-olefin homopolymer or copolymer having 2 to 5 carbons.
Claim 4
Dependent Claim
10 words
The process of claim 2 wherein the alpha-olefin is polypropylene.
Claim 5
Dependent Claim
60 words
The process of claim 1 wherein the treating step is effected at a time/temperature relationship defined by parameters selected from the group consisting of i) not less than 24 hours at 52° C., ii) not less than 8 hours at 55° C., iii) not less than 2 hours at 65° C., iv) not less than 1.5 hours at 75° C.
Claim 6
Dependent Claim
34 words
The process of claim 4 wherein the surface layer comprises 1 to 20%, based on the weight of the core layer, of a copolymer of ethylene/propylene containing 92 to 97% by weight of propylene.
Claim 7
Dependent Claim
53 words
The process of claim 5 wherein the formed and biaxially oriented film comprises isotactic polypropylene having a density from abut 0.86 to about 0.92 g/cc measured at 23° C., a melt flow index of from 1 to 15 g/10 minutes, orientation of 500% in the machine direction and 900% in the transverse direction.
Claim 8
Dependent Claim
56 words
The process of claim 1 wherein the polyolefin film is a laminate having (a) a core layer comprised of 70% to 100% by weight of polypropylene and 0% to 30% by weight hydrogenated terpene or petroleum resin having a molecular weight less than that of said polyolefin, plus (b) at least one heat sealable surface layer.
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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) | 1995-10-06 | 1996-04-06 | 1996-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-06 | 2000-04-06 | 2000-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-06 | 2004-04-06 | 2004-10-06 | $7700.00 | Window Closed / Lapsed |