US4588633A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyethylene microporous membrane of ultra high molecular weight
Assignee: Tonen General Sekiyu KK
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Filing: 1985-04-29
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Granted: 1986-05-13
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Expires: 2005-04-29
Abstract
Abstract A polyethylene microporous membrane having a thickness of at most 10 mu m, a breaking strength of at least 200 kg/cm2 and a porosity of at least 30% is produced by heating and dissolving polyethylene having a weight average molecular weight of at least 5x105 in a solvent, forming a gel sheet from the resulting solution, subjecting the gel sheet to a solvent removal treatment to adjust the amount of the solvent in the gel sheet to 10 to 80% by weight, heating and stretching the sheet and then removing the residual solvent therefrom.
Inventors
- 👤 Koichi Kono
- 👤 Shoichi Mori
- 👤 Kenji Miyasaka
- 👤 Jyoichi Tabuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:56
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/00091; B01D67/0023; B01D67/0025; B01D67/0027; B01D67/0039; B01D67/0046; B01D71/00; B01D71/06; B01D71/26; B01D71/261; B01D2323/00; B01D2323/08; B01D2323/081; B01D2323/12; B01D2325/00; B01D2325/02; B01D2325/0283; B01D2325/04; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/06; Y; Y10; Y10S; Y10S264/00; Y10S264/71; Y10S521/00; Y10S521/918; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
44 words
A polyethylene microporous membrane consisting of polyethylene having a weight average molecular weight of at least 5×10 5 , and having a thickness of at most 10 μm, a breaking strength of at least 200 kg/cm 2 and a porosity of at least 30%.
Claim 2
Dependent Claim
44 words
A polyethylene microporous membrane consisting of polyethylene having a weight average molecular weight of at least 5×10 5 , and having a thickness of at most 10 μm, a breaking strength of at least 200 kg/cm 2 and a porosity of at least 30%.
Claim 3
Dependent Claim
31 words
The polyethylene microporous membrane of claim 1, wherein the thickness is 0.1 to 10 μm, the breaking strength is at least 200 kg/cm 2 and the porosity is 30 to 95%.
Claim 4
Dependent Claim
20 words
The polyethylene microporous membrane of claim 1, wherein the weight average molecular weight is 1×10 6 to 10×10 6 .
References Cited (Backward Citations)
US4539256A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-12 | 1989-11-11 | 1990-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-12 | 1993-11-11 | 1994-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-12 | 1997-11-11 | 1998-05-13 | $7700.00 | Window Closed / Lapsed |