Patent US4755540A successfully refreshed from Google Patents.
US4755540A
Expired / Lapsed
US
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Polymer membrane
Assignee: Scimat Ltd
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Filing: 1985-05-20
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Granted: 1988-07-05
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Expires: 2005-05-20
Abstract
Abstract Porous membranes of aromatic polymer (preferably ether ketone) are prepared with pore size and surface area allowing use in place of asbestos membranes in hot alkaline electrolysis cells. The membranes are prepared by solvent extraction of a polymer which is "partially incompatible" with the aromatic from a blend of the two. The membranes are preferably dried in the presence of a surfactant to enhance re-wetting in use.
Inventors
- 👤 Susan V. Blakey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:47
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0088; C; C25; C25B; C25B13/00; C25B13/04; C25B13/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
75 words
A method of making a polyaryletherketone porous membrane, comprising the steps of: (a) providing a mixture of a first polymeric material, which is a polyaryletherketone, and a second polymeric material, which is partially incompatible with said first polymeric material; (b) forming said mixture into a film; and (c) extracting from said film at least a substantial portion of said second polymeric material by means of a liquid which does not dissolve said first polymeric material.
Claim 2
Independent Claim
75 words
A method of making a polyaryletherketone porous membrane, comprising the steps of: (a) providing a mixture of a first polymeric material, which is a polyaryletherketone, and a second polymeric material, which is partially incompatible with said first polymeric material; (b) forming said mixture into a film; and (c) extracting from said film at least a substantial portion of said second polymeric material by means of a liquid which does not dissolve said first polymeric material.
Claim 3
Dependent Claim
22 words
A method as claimed in claim 1, in which at least 80 percent by weight of said second polymeric material is extracted.
Claim 4
Dependent Claim
31 words
A method as claimed in claim 1, in which the proportion by weight in said mixture of said first polymeric material to said second polymeric material is between 45:55 and 70:30.
Claim 5
Dependent Claim
19 words
A method as claimed in claim 1, further comprising the step of drying said film after said extracting step.
Claim 6
Dependent Claim
19 words
A method as claimed in claim 4, wherein said drying step is performed in the presence of a surfactant.
Claim 7
Dependent Claim
16 words
A method as claimed in claim 1, wherein said second polymeric material is an aromatic polymer.
Claim 8
Dependent Claim
21 words
A method as claimed in claim 6, wherein said second polymeric material comprises an aromatic sulfone or aromatic ether sulfone polymer.
Claim 9
Dependent Claim
23 words
A method as claimed in claim 1, wherein said first polymeric material has a repeat unit selected from the group consisting of: ##STR11##
References Cited (Backward Citations)
GB1213739A
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GB1449644A
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US3930979A
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US4098672A
Cited
FR2300144A1
Cited
GB1506665A
Cited
JPS55106243A
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US4311566A
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US4341619A
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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) | 1991-07-05 | 1992-01-04 | 1992-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-05 | 1996-01-04 | 1996-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-05 | 2000-01-04 | 2000-07-05 | $7700.00 | Window Closed / Lapsed |