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US4474858A
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Aromatic polyimide gas-separating membrane
Assignee: Ube Corp
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Filing: 1982-06-30
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Granted: 1984-10-02
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Expires: 2002-06-30
Abstract
Abstract An aromatic polyimide membrane having an excellent gas-separating property comprises (A) a substrate consisting of a porous membrane comprising at least one aromatic polyimide having at least 80 molar % of at least one type of recurring unit of the formula (I): <IMAGE> (I) wherein R is a tetravalent aromatic radical and R1 is a divalent aromatic radical, the porous membrane exhibiting a hydrogen gas permeability (PH2) of 1x10-5 to 5x10-1 cm3/cm2.sec.cmHg and a ratio of hydrogen gas permeability (PH2) to carbon monoxide gas permeability (PCO) of 2 to 5; and (B) 50% or more, based on the weight of the porous membrane substrate, of a gas-separating liquid contained in the porous membrane substrate, the gas-separating liquid being substantially incapable of dissolving therein the porous membrane substrate and having a boiling point of 180 DEG C. or more.
Inventors
- 👤 Hiroshi Makino
- 👤 Yoshihiro Kusuki
- 👤 Takashi Harada
- 👤 Hiroshi Shimazaki
- 👤 Tosio Isida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:31
CPC Classifications
C; C08; C08L; C08L79/00; C08L79/04; C08L79/08; B; B01; B01D; B01D61/00; B01D61/38; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
176 words
An aromatic polyimide gas-separating membrane comprising: a substrate consisting of an aromatic polyimide porous membrane which comprises an aromatic polyimide material consisting essentially of at least one aromatic polyimide having at least 80 molar % of at least one type of recurring unit of the formula (I): ##STR8## wherein R represents a tetravalent aromatic radical and R 1 represents a divalent aromatic radical and which exhibits a hydrogen gas permeability (P H2 ) of from 1×10 -5 to 5×10 -1 cm 3 /cm 2 .sec.cmHg and a ratio (P H2 /P CO ) of hydrogen gas permeability (P H2 ) to carbon monoxide gas permeability (P CO ) of 2 to 5, determined under a pressure of 1 kg/cm 2 ; and at least 50%, based on the weight of said porous membane substrate, of a gas-separating liquid uniformly impregnated in said porous membrane substrate said gas-separating liquid consisting essentially of at least one liquid naphthalene compound substantially incapable of dissolving therein said porous membrane substrate, and having a boiling point of at least 180° C.
Claim 2
Dependent Claim
176 words
An aromatic polyimide gas-separating membrane comprising: a substrate consisting of an aromatic polyimide porous membrane which comprises an aromatic polyimide material consisting essentially of at least one aromatic polyimide having at least 80 molar % of at least one type of recurring unit of the formula (I): ##STR8## wherein R represents a tetravalent aromatic radical and R 1 represents a divalent aromatic radical and which exhibits a hydrogen gas permeability (P H2 ) of from 1×10 -5 to 5×10 -1 cm 3 /cm 2 .sec.cmHg and a ratio (P H2 /P CO ) of hydrogen gas permeability (P H2 ) to carbon monoxide gas permeability (P CO ) of 2 to 5, determined under a pressure of 1 kg/cm 2 ; and at least 50%, based on the weight of said porous membane substrate, of a gas-separating liquid uniformly impregnated in said porous membrane substrate said gas-separating liquid consisting essentially of at least one liquid naphthalene compound substantially incapable of dissolving therein said porous membrane substrate, and having a boiling point of at least 180° C.
Claim 3
Dependent Claim
57 words
The gas-separating membrane as claimed in claim 1, wherein said tetravalent aromatic radical represented by R in the formula (I) is selected from those of the formulae: ##STR9## wherein 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 --.
Claim 4
Dependent Claim
111 words
The gas-separating membrane as claimed in claim 1, wherein said divalent aromatic radical represented by R 1 in the formula (I) is selected from those of the formulae: ##STR10## wherein 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 --; R 2 , R 3 , and R 4 represent, independently from each other, a member selected from the group consisting of a hydrogen atom, lower alkyl radicals having 1 to 3 carbon atoms, and lower alkoxyl radicals having 1 to 3 carbon atoms; and m represents an integer of 1 to 4.
Claim 5
Dependent Claim
52 words
The gas-separating membrane as claimed in claim 1, wherein said aromatic polyimide material for said porous membrane substrate consists essentially of at least one aromatic polyimide having at least 90 molar % of at least one type of recurring unit of the formula (II): ##STR11## wherein R 1 is as defined above.
Claim 6
Dependent Claim
37 words
The gas-separating membrane as claimed in claim 1, wherein said liquid compound in said gas-separating liquid is incapable of dissolving therein said porous membrane substrate in an amount of 1% by weight or more at room temperature.
Claim 7
Dependent Claim
25 words
The gas-separating membrane as claimed in claim 1, wherein said liquid compound in said gas-separating liquid has a boiling point of 200° C. or more.
Claim 8
Dependent Claim
28 words
The gas-separating membrane as claimed in claim 1 wherein said gas-separating liquid is at least one compound selected from the group consisting of halogenated naphthalenes and alkylated naphthalenes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-02 | 1988-04-02 | 1988-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-02 | 1992-04-02 | 1992-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-02 | 1996-04-02 | 1996-10-02 | $7700.00 | Window Closed / Lapsed |