US4289600A
Expired / Lapsed
US
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Microporous membrane materials
Assignee: Occidental Chemical Corp
•
Filing: 1979-08-07
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Granted: 1981-09-15
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Expires: 1999-08-07
Abstract
Abstract Microporous membrane materials suitable for use in electrolytic cells, such as cells for the electrolysis of brine to produce chlorine, are formed from a mixture of polytetrafluoroethylene, a particulate pore forming material and an organic fluorinated lubricant. Such materials are preferably formed into a sheet, which is rolled to a desired thickness, sintered and subjected to leaching out of the pore forming material.
Inventors
- 👤 Christine A. Lazarz
- 👤 Edward H. Cook, Jr.
- 👤 Lesleigh V. Scripa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:07
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/26; C25; C25B; C25B13/00; C25B13/04; C25B13/08; C08J2327/00; C08J2327/02; C08J2327/12; H; H01; H01M; H01M2300/00; H01M2300/0002; H01M2300/0014; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
58 words
A process for the preparation of a sheet material suitable for use as a separator for an electrolytic cell which comprises: (a) forming a sheet from a composition comprising a fluorocarbon polymer, a pore forming additive and a fluorinated surface active agent; (b) sintering the sheet; and (c) removing the pore forming additive, to form a microporous sheet.
Claim 2
Dependent Claim
58 words
A process for the preparation of a sheet material suitable for use as a separator for an electrolytic cell which comprises: (a) forming a sheet from a composition comprising a fluorocarbon polymer, a pore forming additive and a fluorinated surface active agent; (b) sintering the sheet; and (c) removing the pore forming additive, to form a microporous sheet.
Claim 3
Dependent Claim
30 words
A process according to claim 1 wherein the fluorocarbon polymer is polytetrafluoroethylene, the pore forming additive is a water insoluble particulate material and the fluorinated surface active agent is nonionic.
Claim 4
Dependent Claim
55 words
A process according to claim 2 wherein the nonionic fluorinated surface active agent is of the formula F 3 C(CF 2 ) m CH 2 CH 2 0(CH 2 CH 2 O) n H, where m is in the range of 3 to 19 and n is in the range of from 6 to 19.
Claim 5
Dependent Claim
94 words
A process according to claim 1 wherein the polytetrafluoroethylene powder is of a particle size or mixture of sizes in the range of about 10 to 500 microns, the pore forming material is calcium carbonate of a particle size or mixture of sizes in the range of about 1 to 500 microns and is removed by acid leaching, the proportion of nonionic fluorinated surface active agent in the mix before milling is about 5 to 30% and the proportion of pore former polytetrafluoroethylene, by weight, is in the range of about 10:1 to 1:1.
Claim 6
Dependent Claim
44 words
A process according to claim 4 wherein the sheet being milled is cross-milled at least once, the acid used to remove the pore former from the sintered sheet is hydrochloric acid and the sheet is washed with water after removal of the pore former.
Claim 7
Dependent Claim
21 words
A process according to claim 5 wherein sintering is effected at a temperature in the range of 340° to 360° C.
Claim 8
Dependent Claim
8 words
A product of the process of claim 1.
Claim 9
Dependent Claim
8 words
A product of the process of claim 3.
Claim 10
Dependent Claim
8 words
A product of the process of claim 4.
Claim 11
Independent Claim
34 words
A method of improving the milling characteristics and rolling characteristics of a fluorocarbon polymer--pore forming particulate material mixture which comprises mixing with such mixture a fluorinated surface active agent and milling the mixture resulting.
Claim 12
Independent Claim
34 words
A method of improving the milling characteristics and rolling characteristics of a fluorocarbon polymer--pore forming particulate material mixture which comprises mixing with such mixture a fluorinated surface active agent and milling the mixture resulting.
Claim 13
Dependent Claim
28 words
A method according to claim 10 wherein the fluorocarbon polymer is polytetrafluoroethylene, the pore forming particulate material is water insoluble and the fluorinated surface active agent is nonionic.
Claim 14
Dependent Claim
70 words
A method according to claim 11 wherein the pore forming additive is calcium carbonate and the nonionic fluorinated surface active agent is of the formula F 3 C(CF 2 ) m CH 2 CH 2 O(CH 2 CH 2 O) n H, wherein m is in the range of 3 to 19 and n is in the range of 6 to 19 and milling is conducted at about room temperature.
Claim 15
Dependent Claim
49 words
In the preparation of a microporous sheet material from a fluorocarbon polymer and pore forming material the method of improving the milling and rolling characteristics of a mixture of such polymer and pore forming material which comprises incorporating in the mixture a fluorinated surface active agent which is nonionic.
Claim 16
Dependent Claim
49 words
In the preparation of a microporous sheet material from a fluorocarbon polymer and pore forming material the method of improving the milling and rolling characteristics of a mixture of such polymer and pore forming material which comprises incorporating in the mixture a fluorinated surface active agent which is nonionic.
Claim 17
Dependent Claim
62 words
A method according to claim 1 wherein the pore forming additive is calcium carbonate and the nonionic fluorinated surface active agent is of the formula F 3 C(CF 2 ) m CH 2 CH 2 O(CH 2 CH 2 O) n H, wherein m is in the range of 3 to 19 and n is in the range of 6 to 19.
Claim 18
Dependent Claim
35 words
An electrolytic cell comprising an anode, a cathode and a housing for them, wherein the anode is separated from the cathode by a microporous separator which is a product of the process of claim 1.
Claim 19
Dependent Claim
20 words
An electrolytic cell according to claim 15 wherein the microporous separator is a product of the process of claim 3.
Claim 20
Dependent Claim
20 words
An electrolytic cell according to claim 16 wherein the microporous separator is a product of the process of claim 4.
Claim 21
Dependent Claim
18 words
A method of electrolyzing brine which comprises carrying out the electrolysis in the electrolytic cell of claim 15.
Claim 22
Dependent Claim
14 words
A method according to claim 18 wherein the cell is that of claim 16.
Claim 23
Dependent Claim
14 words
A method according to claim 18 wherein the cell is that of claim 17.
Claim 24
Dependent Claim
108 words
A process for the preparation of a sheet material suitable for use as a separator for an electrolytic cell which comprises: (a) mixing together polytetrafluoroethylene in powder form, a water insoluble particulate pore forming additive and a lower alkanol solution of a nonionic fluorinated surface active agent of the formula F 3 C(CF 2 ) m CH 2 CH 2 O(CH 2 CH 2 O) n H, wherein m is in the range of 3 to 19 and n is in the range of from 6 to 19; (b) milling the mixture to form a sheet; (c) sintering the sheet, and (d) removing the pore forming particulate material.
Claim 25
Dependent Claim
108 words
A process for the preparation of a sheet material suitable for use as a separator for an electrolytic cell which comprises: (a) mixing together polytetrafluoroethylene in powder form, a water insoluble particulate pore forming additive and a lower alkanol solution of a nonionic fluorinated surface active agent of the formula F 3 C(CF 2 ) m CH 2 CH 2 O(CH 2 CH 2 O) n H, wherein m is in the range of 3 to 19 and n is in the range of from 6 to 19; (b) milling the mixture to form a sheet; (c) sintering the sheet, and (d) removing the pore forming particulate material.
Claim 26
Dependent Claim
44 words
In the preparation of a microporous sheet material from polytetrafluoroethylene and a water insoluble particulate pore forming material the method of improving the milling and rolling characteristics of the mixture which comprises incorporating in the mixture a perfluorinated polyethylene glycol nonionic surface active agent.
Claim 27
Dependent Claim
44 words
In the preparation of a microporous sheet material from polytetrafluoroethylene and a water insoluble particulate pore forming material the method of improving the milling and rolling characteristics of the mixture which comprises incorporating in the mixture a perfluorinated polyethylene glycol nonionic surface active agent.
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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) | 1984-09-14 | 1985-03-16 | 1985-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-14 | 1989-03-16 | 1989-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-14 | 1993-03-16 | 1993-09-15 | $7700.00 | Window Closed / Lapsed |