US5686173A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biaxially stretched film for packaging
Assignee: Mitsubishi Chemical Corp
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Filing: 1995-09-12
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Granted: 1997-11-11
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Expires: 2015-09-12
Abstract
Abstract A biaxially stretched film for packaging, having a thickness of not more than 40 mu m; comprising surface layers each made of a propylene-ethylene copolymer resin and an intermediate layer disposed therebetween made of a polyamide resin comprising an aromatic polyamide resin, and having thickness of 10 to 80% of the overall thickness of the biaxially stretched film; and obtained by a process comprising a coextrusion step, a rapid cooling step, and a stretching step.
Inventors
- 👤 Toshio Fujii
- 👤 Kazuhiro Kato
- 👤 Toyomitsu Kondo
- 👤 Sinji Kawasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:12
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/18; B32B27/32; B32B27/34; B32B38/00; B32B38/0012; B32B2038/0028; B32B2307/00; B32B2307/50; B32B2307/514; B32B2307/518; B32B2307/70; B32B2307/718; B32B2307/72; B32B2439/00; B32B2439/70; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/31504; Y10T428/31725; Y10T428/31739; Y10T428/31743; Y10T428/31746; Y10T428/3175; Y10T428/31757; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31928
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
108 words
A biaxially stretched film for packaging, having an overall thickness of 2 to 40 μm; said film comprising surface layers each made of a propylene-ethylene copolymer resin and an intermediate layer disposed therebetween made of a copolyamide or polyamide resin composition comprising 60 to 98% by weight of an aliphatic polyamide resin and 2 to 40% by weight of an aromatic polyamide resin, said intermediate layer having thickness of 10 to 80% of the overall thickness of the biaxially stretched film; and obtained by a process comprising a coextrusion step, using water-cooled inflation or T-die molding by contacting the extrudate with a chill roll, and a stretching step.
Claim 2
Dependent Claim
108 words
A biaxially stretched film for packaging, having an overall thickness of 2 to 40 μm; said film comprising surface layers each made of a propylene-ethylene copolymer resin and an intermediate layer disposed therebetween made of a copolyamide or polyamide resin composition comprising 60 to 98% by weight of an aliphatic polyamide resin and 2 to 40% by weight of an aromatic polyamide resin, said intermediate layer having thickness of 10 to 80% of the overall thickness of the biaxially stretched film; and obtained by a process comprising a coextrusion step, using water-cooled inflation or T-die molding by contacting the extrudate with a chill roll, and a stretching step.
Claim 3
Dependent Claim
22 words
A film according to claim 1, wherein the film is stretched 2 to 6 times in each of machine and transverse directions.
Claim 4
Dependent Claim
49 words
A film according to claim 1, wherein the aromatic polyamide resin is (a) a polymer composed of aliphatic diamine units and isophthalic acid units or terephthalic acid units or both, or (b) a copolyamide composed of aromatic polyamide structural units of (a) and lactam or aliphatic polyamide structural units.
Claim 5
Dependent Claim
56 words
A film according to claim 1, wherein the surface layer comprises (A) 3 to 40 parts by weight of polybutene or polyisobutylene, (B) 0.2 to 10 parts by weight of an anti-fogging agent and (C) 0.1 to 10 parts by weight of a release agent, based on 100 parts by weight of the propylene-ethylene copolymer resin.
Claim 6
Dependent Claim
27 words
A film according to claim 4, wherein the anti-fogging agent is a fatty acid ester formed from a polyhydric alcohol with 3 to 20 of hydroxyl groups.
Claim 7
Dependent Claim
38 words
A film according to claim 4, wherein the release agent is a mixed glyceride having an acyl group with a carbon number of 2 to 6 and an acyl group with a carbon number of 8 to 22.
Claim 8
Dependent Claim
43 words
A film according to claim 1, having a five-layer structure of a propylene-ethylene copolymer resin/acid-modified polyolefin resin/polyamide resin comprising 60 to 98% by weight of an aliphatic polyamide resin and 2 to 40% by weight of an aromatic polyamide resin/acid-modified polyolefin resin/polypropylene-based resin.
Claim 9
Dependent Claim
46 words
A film according to claim 1, wherein the propylene-ethylene copolymer resin has a melt flow rate of 0.5 to 10 g/10 min determined according to JIS K6758 at 230° C. under a load of 2.16 kg and a density of 0.89 to 0.91 g/cm 2 .
Claim 10
Dependent Claim
21 words
A film according to claim 4, wherein the polybutene or the polyisobutylene has a number-average molecular weight of 200 to 5,000.
Claim 11
Dependent Claim
51 words
A film according to claim 5, wherein the fatty acid ester is one in which from one hydroxyl group to 70% of the hydroxyl groups of the polyhydric alcohol with 3 to 20 of hydroxyl groups are esterified with a higher fatty acid having a carbon number of 8 to 22.
Claim 12
Dependent Claim
41 words
A film according to claim 7, wherein the acid-modified polyolefin resin is obtained by graft reacting an unsaturated carboxylic acid or a derivative thereof which is an acid anhydride, an ester, an imide or a metal salt, with a polyolefin resin.
Claim 13
Dependent Claim
43 words
A film according to claim 11, wherein the unsaturated carboxylic acid or a derivative thereof is acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, or an acid anhydride, an ester, an amide, an imide or a metal salt thereof.
Claim 14
Dependent Claim
70 words
A film according to claim 11, wherein the polyolefin resin is polyethylene, polypropylene, a random or block copolymer of propylene and 1 to 5% by weight of ethylene, a random or block copolymer of ethylene and 1 to 10% by weight of propylene, a copolymer of propylene or ethylene and 1 to 10% by weight of an α-olefin having a carbon number of 4 or greater, or a mixture thereof.
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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) | 2000-11-10 | 2001-05-12 | 2001-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-10 | 2005-05-12 | 2005-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-10 | 2009-05-12 | 2009-11-11 | $7700.00 | Window Closed / Lapsed |