EP0037730A2
Expired / Lapsed
EP
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Asymmetric ultrafiltration membrane and production thereof
Assignee: Brunswick Corp
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Filing: 1981-04-06
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Granted: —
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Expires: 2001-04-06
Abstract
Abstract The membrane has a water permeability of at least 0.2 cm/min psi and comprises an open honeycomb structure and a skin integral therewith, the honeycomb structure and the skin both being of a polymer (such as a polyimide) having a glass transition temperature of at least 200°C. The membrane is produced by casting a solution containing not more than 13% by weight of the polymer, into a quench liquid (such as water) which is a non-solvent for the polymer but miscible with the solvent.
Inventors
- 👤 Wolfgang J. Wrasidlo
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 08:41
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/02; B01D71/00; B01D71/06; B01D71/50; B01D71/58; B01D71/62; B01D71/64
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
54 words
An asymmetric ultrafiltration membrane having a water permeability of at least 0.2 cm/min psi, the membrane comprising an open honeycomb structure constituting the majority of the membrane and, integral therewith, a skin, the open honeycomb structure and the skin both being of a polymeric material having a glass transition temperature of at least 200°C.
Claim 2
Dependent Claim
54 words
An asymmetric ultrafiltration membrane having a water permeability of at least 0.2 cm/min psi, the membrane comprising an open honeycomb structure constituting the majority of the membrane and, integral therewith, a skin, the open honeycomb structure and the skin both being of a polymeric material having a glass transition temperature of at least 200°C.
Claim 3
Dependent Claim
17 words
A membrane according to claim 1, wherein the glass transition temperature is at least 250 0 C.
Claim 4
Dependent Claim
21 words
A membrane according to claim 1 or 2, wherein the polymeric material has a modulus of elasticity of at least.100,000 psi.
Claim 5
Dependent Claim
38 words
A membrane according to claim 3, wherein the ratio of the water permeability of the membrane to the square root of the molecular weight cut-off of the polymeric material is greater than 2 x 10 -3 cm/min psi.
Claim 6
Dependent Claim
17 words
A membrane according to any of claims 1 to 4, wherein the polymeric material is a polyimide.
Claim 7
Dependent Claim
20 words
A membrane according to any of claims 1 to 5, wherein the water permeability is at least 0.4 cm/min psi.
Claim 8
Dependent Claim
39 words
A membrane according to any of claims 1 to 6, wherein the honeycomb structure has a wall thickness which decreases as the distance from the skin increases and/or a mesh which increases as the distance from the skin increases.
Claim 9
Independent Claim
66 words
A method of producing an asymmetric ultrafiltration membrane having a water permeability of at least 0.2 cm/min psi, which comprises precipitating a membrane-forming polymeric material having a glass transition temperature of at least 200°C by casting a solution containing not more than 13% by weight of the polymeric material into a quench liquid which is a non-solvent for the polymeric material but miscible with the solvent.
Claim 10
Independent Claim
66 words
A method of producing an asymmetric ultrafiltration membrane having a water permeability of at least 0.2 cm/min psi, which comprises precipitating a membrane-forming polymeric material having a glass transition temperature of at least 200°C by casting a solution containing not more than 13% by weight of the polymeric material into a quench liquid which is a non-solvent for the polymeric material but miscible with the solvent.
Claim 11
Dependent Claim
18 words
A method according to claim 8, wherein the solution contains not more than 10% of the polymeric material.
Claim 12
Dependent Claim
17 words
A method according to claim 9, wherein the solution contains 3 to 7% of the polymeric material.
Claim 13
Independent Claim
25 words
A method according to any of claims 8 to 10, wherein the polymeric material is as defined in any of claims 2, 3 and 5.
Claim 14
Independent Claim
24 words
A method according to any of claims 8 to 11, wherein the solvent is one or more of dimethylformamide, meta-cresol, cresylic acid and chloroform.
Claim 15
Independent Claim
16 words
A method according to any of claims 8 to 12, wherein the quench liquid is water.
References Cited (Backward Citations)
No citation records indexed.
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