Patent US2633174A successfully refreshed from Google Patents.
Patent US4147745A successfully refreshed from Google Patents.
US4147745A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing semipermeable membranes
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1976-08-13
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Granted: 1979-04-03
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Expires: 1996-08-13
Abstract
Abstract A method for the preparation of a semipermeable membrane which comprises exposing porous shaped articles of polyacrylonitrile or copolymers thereof containing acrylonitrile in an amount of more than 40% by mole to a plasma.
Inventors
- 👤 Takezo Sano
- 👤 Takatoshi Shimomura
- 👤 Masao Sasaki
- 👤 Ichiki Murase
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:02
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/40; B01D71/42; B01D71/421; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B29; B29C; B29C59/00; B29C59/14; B29K; B29K2033/00; B29K2033/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
98 words
A method for the preparation of semipermeable membrane which comprises exposing porous shaped articles of polyacrylonitrile or copolymers containing acrylonitrile in an amount of more than 40% by mole to a plasma, wherein said porous shaped articles of said polymeric material are prepared by a method comprising the steps of (a) dissolving the polymeric material in a solvent, (b) casting the resulting solution, (c) dipping the cast solution in a non-solvent to prepare a porous membrane after partial evaporation of the solvent of the solution or without evaporation thereof, and (d) drying the wet porous membrane thus obtained.
Claim 2
Independent Claim
98 words
A method for the preparation of semipermeable membrane which comprises exposing porous shaped articles of polyacrylonitrile or copolymers containing acrylonitrile in an amount of more than 40% by mole to a plasma, wherein said porous shaped articles of said polymeric material are prepared by a method comprising the steps of (a) dissolving the polymeric material in a solvent, (b) casting the resulting solution, (c) dipping the cast solution in a non-solvent to prepare a porous membrane after partial evaporation of the solvent of the solution or without evaporation thereof, and (d) drying the wet porous membrane thus obtained.
Claim 3
Dependent Claim
86 words
A method according to claim 1 wherein said copolymers containing acrylonitrile of more than 40% by mole are those comprising acrylonitrile and one or more components selected from the group consisting of acrylamide, diacetone acrylamide, N-vinyl-2-pyrrolidone, hydroxyethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, acrylic acid, ethylene sulfonic acid, methyacrylic acid, methallyl sulfonic acid, sulfopropyl methacrylate, vinylbenzene sulfonic acid, metal salts thereof, tertiary amines (e.g. 2-vinylpyridine, 4-vinylpyridine, dimethylaminoethyl methacrylate) and quaternary amine salts resulting from alkylation of the tertiary amines.
Claim 4
Dependent Claim
20 words
A method according to claim 1 wherein said compolymers contain acrylonitrile in an amount of 70 to 95% by mole.
Claim 5
Dependent Claim
16 words
A method according to claim 1 wherein the plasma forming gas is hydrogen, helium or argon.
Claim 6
Dependent Claim
17 words
A method according to claim 1 wherein the plasma is generated by glow discharge or corona discharge.
Claim 7
Dependent Claim
34 words
A method according to claim 5 wherein said glow discharge is generated by applying an alternating current or direct current voltage of 0.5 to 50 kV under a pressure of 0.01 to 10 Torr.
Claim 8
Dependent Claim
30 words
A method according to claim 5 wherein said corona discharge is generated with a direct current of 0.1 to 0.3 A at 1 kV under a pressure of 1 atm.
Claim 9
Dependent Claim
27 words
A method according to claim 1 wherein the duration of exposure to plasma is 6 to 120 minutes and the exposure dose is 5 to 100 watt.
Claim 10
Dependent Claim
30 words
A method according to claim 1 wherein said porous shaped articles are in the form of a film, sheet or hollow fiber, or are a composite with other porous supports.
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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) | 1982-04-02 | 1982-10-02 | 1983-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-02 | 1986-10-02 | 1987-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-02 | 1990-10-02 | 1991-04-03 | $7700.00 | Window Closed / Lapsed |