US4818452A
Expired / Lapsed
US
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Method of manufacturing an integral asymmetrical membrane
Assignee: GKSS Forshungszentrum Geesthacht GmbH
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Filing: 1988-05-06
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Granted: 1989-04-04
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Expires: 2008-05-06
Abstract
Abstract A method of manufacturing an integral asymmetrical membrane for the separation of liquid or gaseous mixtures. A membrane-forming agent in the form of a polyetherimide is mixed with a solvent that is miscible with water. The resulting mixture is introduced into or accommodated in a geometrical form. The form is then brought into contact with a precipitating agent and is post-treated.
Inventors
- 👤 Klemens Kneifel
- 👤 Klaus-Viktor Peinemann
- 👤 Rudolf Waldemann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:47
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/08; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; B01D71/643; Y; Y10; Y10S; Y10S264/00; Y10S264/48; Y10S264/62
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
63 words
A method comprising manufacturing an integral asymmetrical hollow-filament membrane for the separation of liquid or gaseous mixtures, by, providing a membrane-forming agent in the form of a polyetherimide; mixing said polyetherimide with a solvent that is miscible with water; then accommodating the resulting polyetherimide/solvent mixture in a geometrical form; and then bringing said form into contact with a precipitating agent and providing posttreatment.
Claim 2
Independent Claim
63 words
A method comprising manufacturing an integral asymmetrical hollow-filament membrane for the separation of liquid or gaseous mixtures, by, providing a membrane-forming agent in the form of a polyetherimide; mixing said polyetherimide with a solvent that is miscible with water; then accommodating the resulting polyetherimide/solvent mixture in a geometrical form; and then bringing said form into contact with a precipitating agent and providing posttreatment.
Claim 3
Dependent Claim
22 words
A method according to claim 1, which includes the step of mixing a water-soluble swelling agent with said polyetherimide/solvent polymer solution mixture.
Claim 4
Dependent Claim
37 words
A method according to claim 2, in which said polyetherimide/solvent polymer solution mixture comprises 10-35% by weight polyetherimide and a solvent selected from the group consisting of N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethyl acetamide (DMAC), and N-formylpiperidine (NFP).
Claim 5
Dependent Claim
23 words
A method according to claim 3, in which said swelling agent is selected from the group consisting of lactones and dimethyl sulfoxide (DMSO).
Claim 6
Dependent Claim
14 words
A method according to claim 4, in which said swelling agent is γ-butyrolactone (GBL).
Claim 7
Dependent Claim
50 words
A method according to claim 1, which includes the step of providing a precipitation bath in the form of a material selected from the group consisting of water, water that contains solvent, water that contains swelling agent, water that contains solvent and swelling agent, and aqueous solutions of organic substances.
Claim 8
Dependent Claim
30 words
A method according to claim 6, in which said precipitation bath comprises an aqueous solution of organic substances selected from the group consisting of polyhydric alcohols, glycerol, and ethylene glycol.
Claim 9
Dependent Claim
25 words
A method according to claim 6, which includes the step of using said precipitation bath as an inner fluid during the manufacture of hollow-filament membranes.
Claim 10
Dependent Claim
25 words
A method according to claim 1, which includes the step of using an inert liquid as an inner fluid during the manufacture of said membrane.
Claim 11
Dependent Claim
18 words
A method according to claim 9, which includes the step of using silicone oil as said inert liquid.
Claim 12
Dependent Claim
19 words
A membrane manufactured pursuant to the method of claim 1 and having a microporous skin that can be coated.
Claim 13
Dependent Claim
16 words
A membrane according to claim 11, in which said membrane has a substructure that contains cavities.
Claim 14
Dependent Claim
14 words
A membrane according to claim 11, in which said membrane has a spongy structure.
Claim 15
Dependent Claim
16 words
A membrane manufactured pursuant to the method of claim 1 and having a thick, nonporous skin.
References Cited (Backward Citations)
US4357401A
Cited
US4673418A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-03 | 1992-10-03 | 1993-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-03 | 1996-10-03 | 1997-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-03 | 2000-10-03 | 2001-04-04 | $7700.00 | Window Closed / Lapsed |