US4869857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing porous membranes
Assignee: Mitsubishi Chemical Corp
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Filing: 1987-05-28
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Granted: 1989-09-26
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Expires: 2007-05-28
Abstract
Abstract Porous membranes are produced by dissolving a film-forming polymer in a good solvent for the polymer, forming a film of the resulting polymer solution, and forcibly contacting saturated steam or mist-containing steam with at least one surface of said film. Such porous membranes have pores having a narrow pore diameter distribution and extending in a direction substantially perpendicular to the membrane surface at a high surface pore density on at least one surface thereof.
Inventors
- 👤 Hajime Itoh
- 👤 Hiroshi Takahashi
- 👤 Kouji Ohbori
- 👤 Hideaki Habara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:34
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0013; B01D67/0016; B01D69/00; B01D69/02; B01D69/06; B01D2323/00; B01D2323/12; B01D2325/00; B01D2325/02; B01D2325/022; C08J2201/00; C08J2201/04; C08J2201/05; C08J2201/0502; C08J2201/054; C08J2201/0542; C08J2201/0544; Y; Y10; Y10S; Y10S264/00; Y10S264/13
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
99 words
A process for producing porous membranes having pores extending in a direction substantially perpendicular to the membrane surface at a high pore density on at least one surface thereof, consisting essentially of dissolving a film-forming polymer in a good solvent for said polymer, forming a film of the resulting polymer solution, and forcibly contacting saturated steam or mist-consisting saturated steam with at least one surface of said film to form pores extending in a direction substantially perpendicular to the membrane surface, wherein said good solvent has a water-solubility of not greater than 50 g per 100 g of water.
Claim 2
Dependent Claim
99 words
A process for producing porous membranes having pores extending in a direction substantially perpendicular to the membrane surface at a high pore density on at least one surface thereof, consisting essentially of dissolving a film-forming polymer in a good solvent for said polymer, forming a film of the resulting polymer solution, and forcibly contacting saturated steam or mist-consisting saturated steam with at least one surface of said film to form pores extending in a direction substantially perpendicular to the membrane surface, wherein said good solvent has a water-solubility of not greater than 50 g per 100 g of water.
Claim 3
Dependent Claim
100 words
A process for producing porous membrane having pores extending in a direction substantially perpendicular to the membrane surface at a high pore density on one surface thereof, consisting essentially of dissolving a film-forming polymer in a good solvent for said polymer, forming a film of the resulting polymer solution on a moving support body, and forcibly contacting saturated steam or mist-containing saturated steam with the surface of said film to form pores extending in a direction substantially perpendicular to the membrane surface, wherein said good solvent has a water-solubility of not greater than 50 g per 100 g of water.
Claim 4
Dependent Claim
100 words
A process for producing porous membrane having pores extending in a direction substantially perpendicular to the membrane surface at a high pore density on one surface thereof, consisting essentially of dissolving a film-forming polymer in a good solvent for said polymer, forming a film of the resulting polymer solution on a moving support body, and forcibly contacting saturated steam or mist-containing saturated steam with the surface of said film to form pores extending in a direction substantially perpendicular to the membrane surface, wherein said good solvent has a water-solubility of not greater than 50 g per 100 g of water.
Claim 5
Dependent Claim
28 words
The process as claimed in claim 1 or 2 wherein said film-forming polymer is dissolved in the good solvent in the range of 2 to 40% by weight.
Claim 6
Dependent Claim
35 words
The process as claimed in claim 1 or 2 wherein said saturated steam or mist-containing saturated steam is supplied at a feed rate of 0.1 to 1000 mg/sec per 1 cm 2 of said film.
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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) | 1992-09-25 | 1993-03-27 | 1993-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-25 | 1997-03-27 | 1997-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-25 | 2001-03-27 | 2001-09-26 | $7700.00 | Window Closed / Lapsed |