US4431504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cation-exchange membrane for electrolyzing alkali metal halide
Assignee: Tosoh Corp
•
Filing: 1982-04-30
•
Granted: 1984-02-14
•
Expires: 2002-04-30
Abstract
Abstract A cation-exchange membrane for electrolyzing an aqueous solution of an alkali metal halide in the manufacture of an alkali hydroxide and a halogen. The membrane comprises one layer which occupies 5 to 30% of the total thickness of the membrane and has carboxylic acid groups; another layer which occupies 5 to 30% of the membrane thickness and has weakly acidic groups, the weakly acidic groups occupying 10 to 60% of the total exchange group capacity of the layer; and a further layer which has sulfonic acid groups occupying the middle portion of the membrane.
Inventors
- 👤 Toru Seita
- 👤 Takao Satoh
- 👤 Mitsuo Kikuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:34
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/34; C25B1/46; C08; C08J; C08J5/00; C08J5/20; C08J5/22; C08J5/2206; C08J5/2275; C08J5/2281; C08J2327/00; C08J2327/02; C08J2327/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
107 words
A cation-exchange membrane for electrolyzing an alkali metal halide having a thickness between 0.05 mm and 1.5 mm and being made from a polymer having 1 equivalent of exchange group to 500 to 2800 g, said membrane comprising a first layer which has carboxylic acid groups and occupies 5 to 30% of the total thickness of the membrane; a second layer which has sulfonic acid groups and weakly acidic groups and occupies 5 to 30% of the total membrane thickness, said weakly acidic groups occupying 10 to 60% of the total exchange group capacity of said second layer; and an intermediate layer which has sulfonic acid groups.
Claim 2
Dependent Claim
107 words
A cation-exchange membrane for electrolyzing an alkali metal halide having a thickness between 0.05 mm and 1.5 mm and being made from a polymer having 1 equivalent of exchange group to 500 to 2800 g, said membrane comprising a first layer which has carboxylic acid groups and occupies 5 to 30% of the total thickness of the membrane; a second layer which has sulfonic acid groups and weakly acidic groups and occupies 5 to 30% of the total membrane thickness, said weakly acidic groups occupying 10 to 60% of the total exchange group capacity of said second layer; and an intermediate layer which has sulfonic acid groups.
Claim 3
Dependent Claim
15 words
A cation-exchange membrane according to claim 1, said membrane being made of a perfluorocarbon polymer.
Claim 4
Dependent Claim
18 words
A cation-exchange membrane according to claim 1 or 2, wherein said weakly acidic groups are carboxylic acid groups.
Claim 5
Dependent Claim
18 words
A cation-exchange membrane according to claim 1 or 2, wherein said weakly acidic groups are phosphoric acid groups.
Claim 6
Dependent Claim
128 words
A cation-exchange membrane according to claim 1, comprising a first layer which has carboxylic acid groups therein and occupies 5 to 30% of the total thickness of the membrane on one side thereof and a second layer which has sulfonic acid groups and occupies the rest of the membrane thickness on the opposite side of said first layer, said second layer including a third layer in which the sulfonic acid groups are replaced with weakly acidic groups to an extent of thickness 5 to 30% of the total membrane thickness from the surface of the second layer, the replacing degree of the weakly acidic groups within said third layer being 10 to 60% of the exchange capacity of the sulfonic acid groups originally existed in the third layer.
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) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |