EP0147570A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Process for the manufacture of asymmetric, porous membranes and product thereof
Assignee: Wyeth Holdings LLC
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Filing: 1984-11-03
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Granted: —
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Expires: 2004-11-03
Abstract
Abstract A process for the production of asymmetric, porous membrane is disclosed which comprises extruding liquified polymer in tubular form and while expanding said film during processing, subjecting it to conditions such that the inside and outside surfaces of the film receive distinct treatments.
Inventors
- 👤 Maurice M. Zwick
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 23:03
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/40; B01D71/42; B01D71/421; B01D63/00; B01D63/06; B01D63/061; B01D71/66; B01D71/68; B29; B29C; B29C48/00; B29C48/03; B29C48/09; B29C48/10; B29C67/00; B29C67/20; B29C67/202; B29C2793/00; B29C2793/0063; B29C48/001; B29C48/0018; B29C48/0019; B29C48/0022; B29K; B29K2033/00; B29K2033/18; B29K2033/20; B29K2081/00; B29K2105/00; B29K2105/04; B29K2105/045; B29L; B29L2031/00; B29L2031/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
114 words
A process for preparing a porous, asymmetric membrane which comprises extruding a liquified film- forming polymer through an annular die to form a tubular film having an internal surface (A) and an external surface (B), said liquified polymer being obtained by use of a polymer solvent alone or in conjunction with one or more melt assistant; biaxially orientating said film while exposing said film to vaporous conditions such that said two surfaces (A) and (B) each receive vapor treatments which differ from one another in at least one condition of temperature and/or chemical composition to provide one dense biaxially oriented surface and one less dense, porous surface and thereafter optionally slitting said tubular film.
Claim 2
Dependent Claim
114 words
A process for preparing a porous, asymmetric membrane which comprises extruding a liquified film- forming polymer through an annular die to form a tubular film having an internal surface (A) and an external surface (B), said liquified polymer being obtained by use of a polymer solvent alone or in conjunction with one or more melt assistant; biaxially orientating said film while exposing said film to vaporous conditions such that said two surfaces (A) and (B) each receive vapor treatments which differ from one another in at least one condition of temperature and/or chemical composition to provide one dense biaxially oriented surface and one less dense, porous surface and thereafter optionally slitting said tubular film.
Claim 3
Dependent Claim
12 words
The process of Claim 1 wherein said polymer is an acrylonitrile copolymer.
Claim 4
Dependent Claim
11 words
The process of Claim 1 wherein said polymer is a polysulfone.
Claim 5
Dependent Claim
16 words
The process of Claim 1 wherein a melt assistant is also present with the polymer solvent.
Claim 6
Dependent Claim
70 words
A porous, asymmetric polymer membrane having two surfaces one of which is denser than the other, said surfaces being biaxially oriented said membrane exhibiting a porosity gradient across its thickness with void spaces generally decreasing in at least one of size and number in the direction of the denser surface, and the density of said denser surface being such that the permeability/imperme- ability characteristics effect chemical separations to be achieved.
Claim 7
Dependent Claim
70 words
A porous, asymmetric polymer membrane having two surfaces one of which is denser than the other, said surfaces being biaxially oriented said membrane exhibiting a porosity gradient across its thickness with void spaces generally decreasing in at least one of size and number in the direction of the denser surface, and the density of said denser surface being such that the permeability/imperme- ability characteristics effect chemical separations to be achieved.
Claim 8
Dependent Claim
12 words
The membrane of Claim 5 wherein said polymer is an acrylonitrile copolymer.
Claim 9
Dependent Claim
11 words
The membrane of Claim 5 wherein said polymer is a polysulfone.
Claim 10
Dependent Claim
15 words
The film membrane of Claim 5 wherein said film provides useful separations in reverse osmosis.
Claim 11
Dependent Claim
15 words
The film membrane of Claim 5 wherein said film provides useful separations is gas separation.
References Cited (Backward Citations)
No citation records indexed.
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