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US4148979A
Expired / Lapsed
US
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Method of improving characteristics of cation-exchange membrane by swelling in water miscible organic solvent
Assignee: Tosoh Corp
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Filing: 1977-04-25
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Granted: 1979-04-10
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Expires: 1997-04-25
Abstract
Abstract A homogeneous cation-exchange membrane made of one or more fluorinated polymer having cation-exchangeable groups is swollen with a water miscible organic solvent and then the solvent is removed from the swollen membrane.
Inventors
- 👤 Shunichi Asami
- 👤 Toru Seita
- 👤 Akihiko Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:58
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/20; C08J5/22; C08J5/2287; C08J5/2293; C08J5/2206; C08J5/2218; C08J5/2231; C08J5/2237; C25; C25B; C25B1/00; C25B1/01; C25B1/34; C25B1/46; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
48 words
A method of improving characteristics of a cation-exchange membrane, which comprises: swelling a homogeneous cation-exchange membrane formed from at least one fluorinated polymer having cation-exchangeable groups with a water miscible organic solvent; and then evaporating said organic solvent from the swollen membrane, thereby obtaining a solvent free membrane.
Claim 2
Independent Claim
48 words
A method of improving characteristics of a cation-exchange membrane, which comprises: swelling a homogeneous cation-exchange membrane formed from at least one fluorinated polymer having cation-exchangeable groups with a water miscible organic solvent; and then evaporating said organic solvent from the swollen membrane, thereby obtaining a solvent free membrane.
Claim 3
Dependent Claim
30 words
The method according to claim 1, wherein said organic solvent is removed from the swollen membrane by holding said membrane between a pair of plates and evaporating said organic solvent.
Claim 4
Dependent Claim
47 words
The method according to claim 1, wherein said water miscible organic solvent is selected from the group consisting of aliphatic monohydric alcohols, ketones, esters, ethers and chloroform which is miscible to water at least 0.1 g/100 g H 2 O of solubility and swells the membrane treated.
Claim 5
Dependent Claim
18 words
The method according to claim 1, wherein said water miscible organic solvent is methanol, ethanol, propanol or butanol.
Claim 6
Dependent Claim
20 words
The method according to claim 1, wherein said water miscible organic solvent is a lower alkyl acetate, tetrahydrofuran, or chloroform.
Claim 7
Dependent Claim
31 words
The method according to claim 1, wherein said cation-exchange membrane is fabricated from at least one fluorinated polymer which has cation-exchangeable sulfonic acid groups and/or carboxylic acid groups or salts thereof.
Claim 8
Dependent Claim
59 words
The method according to claim 1, wherein said cation-exchange membrane is fabricated of at least one fluorinated polymer which is produced by polymerizing fluorinated monomers which include a fluorinated monomer having a functional group which is a sulfonic acid group or a carboxylic acid group or which is convertible to a sulfonic acid group or a carboxylic acid group.
Claim 9
Dependent Claim
57 words
The method according to claim 7, wherein said cation-exchange membrane is prepared by absorbing a fluorinated monomer having the functional group in a fluorinated cation-exchange membrane and polymerizing said fluorinated monomer and hydrolyzing the functional group to the cation-exchangeable group so as to have both of sulfonic acid groups and carboxylic acid groups as the cation-exchangeable groups.
Claim 10
Independent Claim
54 words
A method of improving the characteristics of a cation-exchange membrane, which comprises: swelling a homogeneous cation-exchange membrane formed from at least one fluorinated polymer having cation-exchangeable groups with a water miscible organic solvent; evaporating said organic solvent from the swollen membrane, thereby obtaining a solvent free membrane; and then heat annealing said swollen membrane.
Claim 11
Independent Claim
54 words
A method of improving the characteristics of a cation-exchange membrane, which comprises: swelling a homogeneous cation-exchange membrane formed from at least one fluorinated polymer having cation-exchangeable groups with a water miscible organic solvent; evaporating said organic solvent from the swollen membrane, thereby obtaining a solvent free membrane; and then heat annealing said swollen membrane.
Claim 12
Dependent Claim
23 words
The method of claim 9, wherein said membrane is heat annealed at a temperature ranging from greater than room temperature to 200° C.
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) | 1982-04-09 | 1982-10-09 | 1983-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-09 | 1986-10-09 | 1987-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-09 | 1990-10-09 | 1991-04-10 | $7700.00 | Window Closed / Lapsed |