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Patent US4201641A successfully refreshed from Google Patents.
US4201641A
Expired / Lapsed
US
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Radiation grafting process for preparing a membrane for battery separator
Assignee: Toshiba Ray O Vac Co Ltd
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Filing: 1978-07-21
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Granted: 1980-05-06
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Expires: 1998-07-21
Abstract
Abstract A process is, herein, disclosed for preparing a membrane used for prevention of short-circuiting between the anode and the cathode of a battery comprising contacting a polyethylene film with an aqueous solution of acrylic acid, water, ethylene dichloride and ferrous salt or cupric salt and irradiating with ionizing radiation to obtain a polyethylene film with acrylic acid molecules grafted uniformly thereon.
Inventors
- 👤 Masao Gotoda
- 👤 Toshio Okada
- 👤 Kazuo Murata
- 👤 Kusuhiko Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:01
CPC Classifications
H; H01; H01M; H01M50/00; H01M50/40; H01M50/409; H01M50/411; H01M50/414; H01M50/417; H01M50/489; Y; Y02; Y02E; Y02E60/00; Y02E60/10; Y10; Y10S; Y10S522/00; Y10S522/911; Y10S522/912; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
70 words
A process for preparing a separator membrane for battery comprising contacting polyethylene with an aqueous solution of 30-80% by volume acrylic acid, said aqueous solution further containing at least 3 parts by volume of ethylene dichloride per 100 parts of aqueous solution and 0.001 to 0.1 mole of ferrous salt or cupric salt per liter of the total solution; and then irradiating with ionizing radiation of 0.01 to 2 Mrad.
Claim 2
Dependent Claim
70 words
A process for preparing a separator membrane for battery comprising contacting polyethylene with an aqueous solution of 30-80% by volume acrylic acid, said aqueous solution further containing at least 3 parts by volume of ethylene dichloride per 100 parts of aqueous solution and 0.001 to 0.1 mole of ferrous salt or cupric salt per liter of the total solution; and then irradiating with ionizing radiation of 0.01 to 2 Mrad.
Claim 3
Dependent Claim
15 words
The process of claim 1, wherein the thickness of the polyethylene film is from 10-100μ.
Claim 4
Dependent Claim
26 words
The process of claim 1, wherein the ferrous salt is one selected from the group consisting of Mohr's salt, ferrous chloride, ferrous nitrate and ferrous sulfate.
Claim 5
Dependent Claim
25 words
The process of claim 1, wherein the cupric salt is selected from the group consisting of cupric sulfate, cupric chloride, cupric nitrate, and cupric acetate.
Claim 6
Dependent Claim
19 words
The process of claim 1, wherein the dose of ionizing radiation is the range of 0.01 to 1 Mrad.
Claim 7
Dependent Claim
18 words
The process of claim 1, wherein the polyethylene film is low-density polyethylene prepared by a high pressure method.
Claim 8
Dependent Claim
11 words
The process of claim 1 wherein said polyethylene film is cross-linked.
Claim 9
Dependent Claim
14 words
The process of claim 1 wherein the thickness of the polyethylene film is 10-50μ.
Claim 10
Dependent Claim
38 words
A battery membrane separator membrane of uniform properties and low electrical resistivity made by the process of claim 2 wherein the weight of grafted polyethylene is 40% to 150% greater than the weight of the starting polyethylene film.
Claim 11
Dependent Claim
32 words
A battery separator membrane in accordance with claim 9 wherein the starting polyethylene film is low-density polyethylene of 10-50μ thickness, said membrane having a resistivity of less than 320 mΩ/cm 2 /sheet.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-05-06 | 1983-11-05 | 1984-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-06 | 1987-11-05 | 1988-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-06 | 1991-11-05 | 1992-05-06 | $7700.00 | Window Closed / Lapsed |