Patent US4618534A successfully refreshed from Google Patents.
US4618534A
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Composite membrane and process for producing the same
Assignee: Nitto Denko Corp
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Filing: 1984-10-23
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Granted: 1986-10-21
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Expires: 2004-10-23
Abstract
Abstract A composite membrane and a process for producing the same are described. This composite membrane comprises a polyimide resin anisotropic membrane and a cross-linked silicone resin thin film formed on the anisotropic membrane, the anisotropic membrane comprising a dense surface layer and a porous layer continuously connected thereto and the polyimide resin consisting essentially of a repeating unit of the formula: ##STR1## wherein A and R 1 are the same as defined hereinbefore. This composite membrane is useful for separation of organic solutions containing relatively small solutes of molecular weight of the order of 10 to 1,000 liquid/liquid separation, and concentration and separation of gases.
Inventors
- 👤 Akio Iwama
- 👤 Kentaro Tasaka
- 👤 Yoshitaka Kazuse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:25
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/70; B01D69/00; B01D69/12; B01D69/125; B01D71/58; B01D71/62; B01D71/64; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978; Y10T428/249979; Y10T428/249981
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
96 words
A composite membrane comprising an anisotropic membrane made of a polyimide resin comprising a dense surface layer and a porous layer continuously connected to the dense surface layer, said polyimide resin consisting essentially of a repeating unit represented by the formula: ##STR19## wherein A is a tetravalent aliphatic or aromatic group, and R 1 is a divalent aromatic, alicyclic or aliphatic hydrocarbon group, or a divalent organic group comprising the hydrocarbon groups linked with a divalent organic linking group, and a cross-linked silicone resin thin film formed on the dense surface layer of the anisotropic membrane.
Claim 2
Dependent Claim
96 words
A composite membrane comprising an anisotropic membrane made of a polyimide resin comprising a dense surface layer and a porous layer continuously connected to the dense surface layer, said polyimide resin consisting essentially of a repeating unit represented by the formula: ##STR19## wherein A is a tetravalent aliphatic or aromatic group, and R 1 is a divalent aromatic, alicyclic or aliphatic hydrocarbon group, or a divalent organic group comprising the hydrocarbon groups linked with a divalent organic linking group, and a cross-linked silicone resin thin film formed on the dense surface layer of the anisotropic membrane.
Claim 3
Dependent Claim
24 words
The composite membrane as claimed in claim 1, wherein the polyimide resin anisotropic membrane has the molecular weight cut-off of from 1,000 to 100,000.
Claim 4
Dependent Claim
23 words
The composite membrane as claimed in claim 1, wherein said polyimide resin consists essentially of the repeating unit represented by the formula ##STR20##
Claim 5
Dependent Claim
13 words
The composite membrane as claimed in claim 1, wherein R 1 is ##STR21##
Claim 6
Dependent Claim
120 words
A process for producing a composite membrane which comprises bringing an organic solution of a cross-linkable silicone resin into contact with a dense surface layer of a polyimide resin anisotropic membrane comprising the dense surface layer and a porous layer continuously connected to the dense surface layer, said polyimide resin consisting essentially of a repeating unit represented by the formula: ##STR22## wherein A is a tetravalent aliphatic or aromatic group, and R 1 is a divalent aromatic, alicyclic or aliphatic hydrocarbon group, or a divalent organic group comprising the hydrocarbon groups linked with a divalent organic linking group, and, cross-linking the silicone resin to form a cross-linked silicone resin thin film on the dense surface layer of the anisotropic membrane.
Claim 7
Dependent Claim
120 words
A process for producing a composite membrane which comprises bringing an organic solution of a cross-linkable silicone resin into contact with a dense surface layer of a polyimide resin anisotropic membrane comprising the dense surface layer and a porous layer continuously connected to the dense surface layer, said polyimide resin consisting essentially of a repeating unit represented by the formula: ##STR22## wherein A is a tetravalent aliphatic or aromatic group, and R 1 is a divalent aromatic, alicyclic or aliphatic hydrocarbon group, or a divalent organic group comprising the hydrocarbon groups linked with a divalent organic linking group, and, cross-linking the silicone resin to form a cross-linked silicone resin thin film on the dense surface layer of the anisotropic membrane.
Claim 8
Dependent Claim
23 words
The process as claimed in claim 5, wherein the polyimide resin anisotropic membrane has the molecular weight cut-off of from 1,000 to 100,000.
Claim 9
Dependent Claim
114 words
The process as claimed in claim 5, wherein the cross-linkable silicone resin is a compound represented by the formula: ##STR23## wherein X 1 and X 2 each is a reactive group selected from the group consisting of a vinyl group, an acryloxyalkyl group, a methacryloxyalkyl group, a hydroxyl group, a hydroxyalkyl group, an acyloxy group, an aminoalkyl group and a carboxyalkyl group, R 2 , R 3 , R 4 , R 5 , R 6 and R 7 each is an organic group selected from the group consisting of an alkyl group, a halogenated alkyl group, a vinyl group and an aryl group, and n is an integer of from 400 to 1,000.
Claim 10
Dependent Claim
33 words
The process as claimed in claim 5, wherein the average molecular weight of the cross-linkable silicone resin is equivalent to or greater than the molecular weight cut-off of the polyimide resin anisotropic membrane.
Claim 11
Dependent Claim
25 words
The process as claimed in claim 5, wherein the concentration of the cross-linkable silicone resin in the solution is from 0.01 to 10% by weight.
Claim 12
Dependent Claim
21 words
The composite membrane as claimed in claim 1, wherein said polyimide resin has an intrinsic viscosity of from 0.5 to 2.0.
Claim 13
Dependent Claim
49 words
The composite membrane as claimed in claim 1, wherein said cross-linked silicone resin film is formed by contacting said dense surface layer with an organic solvent solution of a cross-linkable silicone resin which is then cross-linked to yield said cross-linked silicone resin thin film on said dense surface layer.
Claim 14
Dependent Claim
22 words
The composite membrane as claimed in claim 11, wherein said cross-linkable silicone resin has an average molecular weight of 1,000 to 1,000,000.
Claim 15
Dependent Claim
40 words
The composite membrane as claimed in claim 12, wherein said organic solvent is selected from the group consisting of aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, alcohol solvents, carboxylic acid solvents, ester solvents, ketone solvents, ether solvents and halogenated hydrocarbon solvents.
Claim 16
Dependent Claim
24 words
The composite membrane as claimed in claim 1, wherein said cross-linked silicone resin thin film has a thickness of from 10 to 5,000 Angstroms.
Claim 17
Dependent Claim
115 words
The composite membrane as claimed in claim 12, wherein said cross-linkable silicone resin is a compound represented by the formula: ##STR24## wherein X 1 and X 2 each is a reactive group selected from the group consisting of a vinyl group, an acryloxyalkyl group, a methacryloxyalkyl group, a hydroxyl group, a hydroxyalkyl group, an acyloxy group, an aminoalkyl group and a carboxyalkyl group, R 2 , R 3 , R 4 , R 5 , R 6 and R 7 each is an organic group selected from the group consisting of an alkyl group, a halogenated alkyl group, a vinyl group and an aryl group, and n is an integer of from 400 to 1,000.
Claim 18
Dependent Claim
20 words
The process as claimed in claim 5, wherein said polyimide resin has an intrinsic viscosity of from 0.5 to 2.0.
Claim 19
Dependent Claim
21 words
The process as claimed in claim 7, wherein said cross-linkable silicone resin has an average molecular weight of 1,000 to 1,000,000.
Claim 20
Dependent Claim
39 words
The process as claimed in claim 7, wherein said organic solvent is selected from the group consisting of aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, alcohol solvents, carboxylic acid solvents, ester solvents, ketone solvents, ether solvents and halogenated hydrocarbon solvents.
Claim 21
Dependent Claim
23 words
The process as claimed in claim 17, wherein said cross-linked silicone resin thin film has a thickness of from 10 to 5,000 Angstroms.
Claim 22
Dependent Claim
22 words
The process as claimed in claim 5, wherein said polyimide resin consists essentially of the repeating unit represented by the formula: ##STR25##
Claim 23
Dependent Claim
12 words
The process as claimed in claim 5, wherein R 1 is ##STR26##
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1989-10-20 | 1990-04-21 | 1990-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-20 | 1994-04-21 | 1994-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-20 | 1998-04-21 | 1998-10-21 | $7700.00 | Window Closed / Lapsed |