US4528004A
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US
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Aromatic polyimide composite separating membrane
Assignee: Ube Corp
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Filing: 1984-01-30
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Granted: 1985-07-09
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Expires: 2004-01-30
Abstract
Abstract An aromatic polyimide composite membrane having a satisfactory gas-permeating property and an excellent gas-separating property comprises an aromatic polyimide porous membrane substrate and at least one coating layer which has been prepared (A) by coating at least one surface of the substrate with a dilute dope solution containing 0.01 to 5 parts by weight of a soluble aromatic polyimide and/or polyamic acid dissolved in a solvent which consists essentially of 100 parts by weight of a base component incapable of dissolving therein the substrate in an amount of 3% by weight or more and 0 to 15 parts by weight of an additional component capable of dissolving therein the 5% by weight or more of the aromatic polymeric material and compatible with the base component; and (B) by gradually evaporating the solvent from the coated dilute dope solution layer.
Inventors
- 👤 Hiroshi Makino
- 👤 Yoshihiro Kusuki
- 👤 Takashi Harada
- 👤 Hiroshi Shimazaki
- 👤 Tosio Isida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:40
CPC Classifications
C; C08; C08L; C08L79/00; C08L79/04; C08L79/08; B; B01; B01D; B01D69/00; B01D69/12; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; B01D71/641; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
385 words
A process for producing an aromatic polyimide composite separating membrane comprising: (A) preparing a substrate consisting of an aromatic polyimide porous membrane (1) by forming a dope solution of an aromatic polymeric material consisting essentially of at least one member selected from the group consisting of aromatic polyamides and aromatic polyamic acids and dissolved in a concentration of from 3% to 30% by weight in a solvent consisting essentially of a mixture of 100 parts by weight of at least one polar organic liquid compound capable of dissolving therein at least 5% by weight of said aromatic polymeric material and 5 to 100 parts by weight of at least one additional aromatic compound incapable of dissolving therein an amount of more then 3% by weight of said aromatic polymeric material, compatible with said polar organic liquid compound and having a poorer evaporating rate than that of said polar organic liquid compound, (2) by forming a thin layer of said dope solution, and (3) by drying said thin dope solution layer and then heating said dried layer at an elevated temperature, whereby said thin dope solution layer is converted to a thin solid porous membrane, and where said aromatic polymeric material in said dope solution contains an aromatic polyamic acid, said heating procedure is carried out under conditions adequate to convert said aromatic polyamic acid into the corresponding aromatic polyimide; (B) coating at least one surface of said aromatic polyimide porous membrane substrate with a dilute dope solution containing 0.01 to 5 parts by weight of an aromatic polymeric material consisting essentially of at least one polymer selected from the group consisting essentially of soluble aromatic polyimides and aromatic polyamic acids dissolved in a solvent consisting essentially of 100 parts by weight of a base component consisting of at least one organic liquid compound incapable of dissolving therein more than 3% by weight of said aromatic polymeric material in said porous membrane substrate and 0 to 15 parts by weight of an additional component consisting of at least one organic polar liquid compound capable of dissolving therein more than 5% by weight of said aromatic polymeric material and compatible with said base component, to form a coating layer of said dilute dope solution, and (C) evaporating said solvent from said coating layer of said dope solution.
Claim 2
Dependent Claim
385 words
A process for producing an aromatic polyimide composite separating membrane comprising: (A) preparing a substrate consisting of an aromatic polyimide porous membrane (1) by forming a dope solution of an aromatic polymeric material consisting essentially of at least one member selected from the group consisting of aromatic polyamides and aromatic polyamic acids and dissolved in a concentration of from 3% to 30% by weight in a solvent consisting essentially of a mixture of 100 parts by weight of at least one polar organic liquid compound capable of dissolving therein at least 5% by weight of said aromatic polymeric material and 5 to 100 parts by weight of at least one additional aromatic compound incapable of dissolving therein an amount of more then 3% by weight of said aromatic polymeric material, compatible with said polar organic liquid compound and having a poorer evaporating rate than that of said polar organic liquid compound, (2) by forming a thin layer of said dope solution, and (3) by drying said thin dope solution layer and then heating said dried layer at an elevated temperature, whereby said thin dope solution layer is converted to a thin solid porous membrane, and where said aromatic polymeric material in said dope solution contains an aromatic polyamic acid, said heating procedure is carried out under conditions adequate to convert said aromatic polyamic acid into the corresponding aromatic polyimide; (B) coating at least one surface of said aromatic polyimide porous membrane substrate with a dilute dope solution containing 0.01 to 5 parts by weight of an aromatic polymeric material consisting essentially of at least one polymer selected from the group consisting essentially of soluble aromatic polyimides and aromatic polyamic acids dissolved in a solvent consisting essentially of 100 parts by weight of a base component consisting of at least one organic liquid compound incapable of dissolving therein more than 3% by weight of said aromatic polymeric material in said porous membrane substrate and 0 to 15 parts by weight of an additional component consisting of at least one organic polar liquid compound capable of dissolving therein more than 5% by weight of said aromatic polymeric material and compatible with said base component, to form a coating layer of said dilute dope solution, and (C) evaporating said solvent from said coating layer of said dope solution.
Claim 3
Dependent Claim
54 words
The process of claim 1 wherein said aromatic polyimide porous membrane substrate exhibits a hydrogen gas permeability (ρH 2 ) greater than 1×10 -7 cm 3 /cm 2 ·sec·cmHg and a ratio (ρH 2 /CO) of the hydrogen gas permeability (ρH 2 ) to the carbon monoxide gas permeability (ρCO) of 2 to 50.
Claim 4
Dependent Claim
21 words
The process of claim 1, wherein said aromatic polyimide porous membrane substrate has a thickness of from 2 to 500 microns.
Claim 5
Dependent Claim
55 words
The process of claim 1, wherein said porous membrane substrate consists essentially of at least one aromatic polymer having at least 80 molar % of at least one recurring unit selected from those of the formulae (I) and (II): ##STR6## wherein R represents a tetravalent aromatic radical, and R 1 represents a divalent aromatic radical.
Claim 6
Dependent Claim
56 words
The process of claim 4, wherein said tetravalent aromatic radical represented by R in the formulae (I) and (II) is selected from those of the formulae: ##STR7## wherein A represents a divalent linking moiety selected from the group consisting of --CO--, --S--, --O--, --SO 2 --, --SO--, --CH 2 --, and --C(CH 3 ) 2 --.
Claim 7
Dependent Claim
117 words
The process of claim 4, wherein said divalent aromatic radical represented by R 1 in formulae (I) and (II) is selected from those of formulae: ##STR8## wherein X 1 , X 2 , and X 3 represent, independently from each other, a member selected from the group consisting of a hydrogen atom, the lower alkyl radicals having 1 to 3 carbon atoms and the lower alkoxyl radicals having 1 to 3 carbon atoms, X 3 represents a carboxyl radical; A' represents a divalent linking moiety selected from the group consisting of --O--, --S--, --CO--, --SO 2 --, --SO--, --CH 2 --, and --C(CH 3 ) 2 --; and m represents an integer of from 1 to 4.
Claim 8
Dependent Claim
55 words
The process of claim 1, wherein said polymeric material for said porous membrane substrate consists essentially of at least one aromatic polyimide and said solvent for said aromatic polymeric material consists essentially of at least one phenolic compound selected from the group consisting of monohydric phenol compounds, dihydric phenol compounds, halogenated phenols, and halogenated cresols.
Claim 9
Dependent Claim
25 words
The process of claim 1, wherein said additional aromatic compound is incapable of dissolving therein more than 1.5% by weight of said aromatic polymeric material.
Claim 10
Dependent Claim
29 words
The process of claim 1, wherein said additional aromatic compound has a boiling point of at least 5° C. above the boiling point of said polar organic liquid compound.
Claim 11
Dependent Claim
29 words
The process of claim 1, wherein said thin layer of said dope solution for said porous membrane substrate is formed at a temperature of from 0° to 120° C.
Claim 12
Dependent Claim
31 words
The process of claim 1, wherein said thin layer of said dope solution for said porous membrane substrate is dried and heated at a temperature of from 20° to 400° C.
Claim 13
Dependent Claim
120 words
The process of claim 1, wherein in said dilute dope solution said aromatic polymeric material for said coating layer consists essentially of at least one aromatic polymer having at least 70 molar % of at least one recurring unit selected from those of the formulae (I) and (II): ##STR9## wherein R represents a tetravalent aromatic radical and R 1 represents a divalent aromatic radical; said base component in said solvent consists essentially of at least one member selected from the group consisting of halogenated hydrocarbon liquid compounds, amide liquid compounds, alkylsulfoxide liquid compounds, alkylurea-type liquid compounds, cyclic ether-type liquid compounds, and glycol-type liquid compounds; and said additional component of said solvent consists essentially of at least one phenolic liquid compound.
Claim 14
Dependent Claim
126 words
The process of claim 12, wherein said aromatic polymeric material for said coating layer is an aromatic polyimide material consisting essentially of at least one soluble aromatic polyimide having at least 70 molar % of at least one recurring unit selected from those of the formulae (III) and (IV): ##STR10## wherein R 1 represents a divalent aromatic radical, and said solvent consists essentially of 85 to 95% by weight of a base component consisting essentially of at least one member selected from the group consisting of halogenated hydrocarbon liquid compounds, amide liquid compounds, alkylsulfoxide liquid compounds, alkylurea liquid compounds, cyclic ether liquid compounds, and glycol liquid compounds and 5 to 15% by weight of an additional component consisting essentially of at least one phenolic liquid component.
Claim 15
Dependent Claim
95 words
The process of claim 12, wherein said aromatic polymeric material for said coating layer is an aromatic polyamic acid consisting essentially of at least one aromatic polyamic acid having at least 40 molar % of at least one recurring unit of the formula (II), the balance consisting essentially of at least one recurring unit of the formula (I), and said solvent consist essentially of a base component of at least one member selected from the group consisting of amide liquid compounds, alkylsulfoxide liquid compounds, alkylurea liquid compounds, cyclic ether liquid compounds, and glycol liquid compounds.
Claim 16
Dependent Claim
97 words
The process of claim 12, wherein said dilute dope solution of said aromatic polymeric material for said coating layer is an aromatic polyimide material consisting essentially of at least one aromatic polyimide having at least 70 molar % of at least one recurring unit selected from those of the formulae (III) and (IV), and said solvent consists essentially of 100 parts by weight of a base component consisting essentially of at least one halogenated hydrocarbon liquid compound and 0.5 to 15 parts by weight of an additional component consisting essentially of at least one phenolic liquid compound.
Claim 17
Dependent Claim
23 words
The process of claim 1, wherein said dilute dope solution for said coating layer has a rotation viscosity of 1 to 500,000 centipoises.
Claim 18
Dependent Claim
20 words
The process of claim 1, wherein said porous membrane is coated at a temperature of from 0° to 80° C.
Claim 19
Dependent Claim
24 words
The process of claim 1, wherein the thickness of the dilute dope coating layer is in the range of from 0.1 to 200 microns.
Claim 20
Dependent Claim
27 words
The process of claim 1, wherein said solvent is evaporated from said dilute dope solution coating layer by heating at a temperature of 20° to 300° C.
Claim 21
Dependent Claim
18 words
The process of claim 1, wherein said coating layer has a thickness of not more than 5 microns.
Claim 22
Dependent Claim
56 words
An aromatic polyimide composite separating membrane of the process of claim 1 having a hydrogen gas permeability (H 2 ) of at least 1×10 - cm 3 /cm 2 sec cmHg and a ratio (ρH 2 /ρCO) of the hydrogen gas permeability (ρH 2 ) to the carbon monoxide gas permeability (ρCO) of at least 95.
Claim 23
Dependent Claim
17 words
An aromatic polyimide composite separating membrane produced in accordance with the process as claimed in claim 1.
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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) | 1988-07-08 | 1989-01-07 | 1989-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-08 | 1993-01-07 | 1993-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-08 | 1997-01-07 | 1997-07-09 | $7700.00 | Window Closed / Lapsed |