US4378324A
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Process for preparing aromatic polyimide semipermeable membranes
Assignee: Ube Corp
•
Filing: 1980-07-23
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Granted: 1983-03-29
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Expires: 2000-07-23
Abstract
Abstract A polyimide semipermeable membrane is prepared by the process comprising the steps of: preparing a solution of a polyimide material consisting essentially of at least one aromatic polyimide comprising at least 90 molar % of at least one recurring unit of the formula (I): <IMAGE> (I) wherein R represents a divalent aromatic radical, in a solvent consisting of at least one phenol compound in the state of a liquid or melt; forming a thin layer of the polyimide solution, and; coagulating the thin layer of the polyimide solution by bringing the thin layer into contact with a coagulating liquid to form a semipermeable membrane.
Inventors
- 👤 Hiroshi Makino
- 👤 Yoshihiro Kusuki
- 👤 Hiroshi Yoshida
- 👤 Asumaru Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:32
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1046; C08G73/105; C08G73/1057; C08G73/1064; C08G73/1067; C08G73/1071; Y; Y10; Y10S; Y10S264/00; Y10S264/62
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
256 words
A process for preparing an aromatic polyimide semipermeable membrane, comprising the steps of: preparing a solution of an aromatic polyimide material consisting essentially of at least one aromatic polyimide comprising at least 90 molar % of at least one recurring unit of the formula (I): ##STR16## wherein R represents a divalent aromatic radical which is selected from the group consisting of those of the formulae (IV) and (V): ##STR17## wherein R 1 and R 2 , respectively, 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 alkoxy radicals having 1 to 3 carbon atoms, and A represents a divalent bond selected from the group consisting of --O--, --S--, --CO--, --SO 2 --, --SO--, --CH 2 -- and --C(CH 3 ) 2 --, and; ##STR18## wherein R 1 and R 2 are as defined above, in a solvent consisting of at least one phenol compound in the state of a liquid or melt; forming a thin layer of said aromatic polyimide solution; and coagulating said thin layer of said aromatic polyimide solution by bringing said thin layer into contact with a coagulating liquid to form a semipermeable membrane, said coagulating liquid consisting of at least one member selected from the group consisting of lower aliphatic alcohols having 1 to 5 carbon atoms, lower aliphatic ketones having 3 to 5 carbon atoms, ether compounds, amide compounds, dimethylsufoxide, and mixtures of at least one member of the above-mentioned compounds with water.
Claim 2
Dependent Claim
256 words
A process for preparing an aromatic polyimide semipermeable membrane, comprising the steps of: preparing a solution of an aromatic polyimide material consisting essentially of at least one aromatic polyimide comprising at least 90 molar % of at least one recurring unit of the formula (I): ##STR16## wherein R represents a divalent aromatic radical which is selected from the group consisting of those of the formulae (IV) and (V): ##STR17## wherein R 1 and R 2 , respectively, 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 alkoxy radicals having 1 to 3 carbon atoms, and A represents a divalent bond selected from the group consisting of --O--, --S--, --CO--, --SO 2 --, --SO--, --CH 2 -- and --C(CH 3 ) 2 --, and; ##STR18## wherein R 1 and R 2 are as defined above, in a solvent consisting of at least one phenol compound in the state of a liquid or melt; forming a thin layer of said aromatic polyimide solution; and coagulating said thin layer of said aromatic polyimide solution by bringing said thin layer into contact with a coagulating liquid to form a semipermeable membrane, said coagulating liquid consisting of at least one member selected from the group consisting of lower aliphatic alcohols having 1 to 5 carbon atoms, lower aliphatic ketones having 3 to 5 carbon atoms, ether compounds, amide compounds, dimethylsufoxide, and mixtures of at least one member of the above-mentioned compounds with water.
Claim 3
Dependent Claim
53 words
A process as claimed in claim 1, wherein said polyimide material exhibits a logarithmic viscosity of from 0.3 to 7.0, determined at a concentration of 0.5 g per 100 ml of a mixture of 4 parts by volume of p-chlorophenol and 1 part by volume of o-chlorophenol at a temperature of 30° C.
Claim 4
Dependent Claim
26 words
A process as claimed in claim 1, wherein said recurring unit of the formula (I) is selected from those of the formulae (II) and (III): ##STR19##
Claim 5
Dependent Claim
65 words
A process as claimed in claim 1, wherein said aromatic polyimide comprises at least one recurring unit of the formula (I) in which R represents a divalent aromatic radical of the formula (IV) and at least one recurring unit of the formula (I) in which R represents a divalent aromatic radical selected from the group consisting of those of the formulae (VI) to (IX): ##STR20##
Claim 6
Dependent Claim
87 words
A process as claimed in claim 1, wherein said aromatic polyimide is one which has been prepared by the polymerization and the imide ring cyclization of a tetracarboxylic acid component comprising 90 molar % or more of biphenyl tetracarboxylic acid of the formula (X): ##STR21## or its anhydride, salt or ether, with an aromatic diamine component consisting essentially of at least one member selected from the group consisting of diamine compounds of the formula (XI): H.sub.2 N--R--NH.sub.2 (XI) wherein R is the same as that defined above.
Claim 7
Dependent Claim
26 words
A process as claimed in claim 5, wherein said biphenyl tetracarboxylic acid of the formula (X) is selected from 2,3,3',4'-biphenyl tetracarboxylic acid and 3,3',4,4'-biphenyl tetracarboxylic acid.
Claim 8
Dependent Claim
112 words
A process as claimed in claim 5, wherein said aromatic diamine of the formula (XI) is selected from the group consisting of those of the formulae (XII) and (XIII): ##STR22## wherein R 1 and R 2 respectively, independently from each other, represent a member selected from the group consisting of a hydrogen atom, lower alkyl radical having 1 to 3 carbon atoms, and lower alkoxy radical having 1 to 3 carbon atoms, and A represents a divalent bond selected from the group consisting of --O--, --S--, --CO--, --SO 2 --, --SO--, --CH 2 -- and --C(CH 3 ) 2 --, and; ##STR23## wherein R 1 and R 2 are as defined above.
Claim 9
Dependent Claim
50 words
A process as claimed in claim 5, wherein said aromatic diamine component comprises at least one aromatic diamine selected from the group consisting of those of the formula (XII) and at least one other aromatic diamine selected from the group consisting of those of the formulae (XIV) to (XVII): ##STR24##
Claim 10
Dependent Claim
60 words
A process as claimed in claim 1, wherein said aromatic polyimide polymer comprises 50 to 95 molar % of a recurring unit of the formula (XVIII): ##STR25## and 5 to 40 molar % of at least one recurring unit selected from those of the formula (XIX): ##STR26## wherein R 3 represents a member selected from the group consisting of: ##STR27##
Claim 11
Dependent Claim
46 words
A process as claimed in claim 1, wherein said polyimide material consists of a high molecular weight aromatic polyimide component having a logarithmic viscosity of from 0.8 to 7 and a low molecular weight aromatic polyimide component having a logarithmic viscosity of from 0.2 to 0.8.
Claim 12
Dependent Claim
38 words
A process as claimed in claim 10, wherein the ratio in weight of said high molecular weight aromatic polyimide component to said low molecular weight aromatic imide polymer component is in a range of from 0.5:1 to 20:1.
Claim 13
Dependent Claim
19 words
A process as claimed in claim 1, wherein said phenol compound has a melting point not exceeding 100° C.
Claim 14
Dependent Claim
31 words
A process as claimed in claim 1, wherein said phenol compound is selected from the group consisting of phenol, o-, m-, and p-cresols, 3,5-xylenol, 1,4-xylenol, carvacrol, thimol and halogenated phenol compounds.
Claim 15
Dependent Claim
47 words
A process as claimed in claim 13, wherein said halogenated phenol compounds are of the formulae: ##STR28## wherein R 4 represents a member selected from the group consisting of a hydrogen atom and alkyl radicals having 1 to 3 carbon atoms, and X represents a halogen atom.
Claim 16
Dependent Claim
33 words
A process as claimed in claim 13, wherein said halogenated phenol compound is selected from the group consisting of 3-chlorophenol, 4-chlorophenol, 3-bromophenol, 4-bromophenol, 2-chloro-4-hydroxytoluene, 2-chloro-5-hydroxytoluene, 3-chloro-5-hydroxytoluene, 3-chloro-6-hydroxytoluene, 4-chloro-2-hydroxytoluene, 2-bromo-4-hydroxytoluene, 2-bromo-5-hydroxytoluene, 3-bromo-5-hydroxytoluene, 3-bromo-6-hydroxytoluene, 4-bromo-2-hydroxytoluene.
Claim 17
Dependent Claim
24 words
A process as claimed in claim 1, wherein the concentration of said polyimide material in said polyimide solution is at least 5% by weight.
Claim 18
Dependent Claim
29 words
A process as claimed in claim 1, wherein said polyimide solution has a rotation viscosity of 1000 centipoises or more at a temperature of from 0° to 120° C.
Claim 19
Dependent Claim
26 words
A process as claimed in claim 1, wherein said thin layer of said polyimide solution is formed at a temperature of from 0° to 120° C.
Claim 20
Dependent Claim
29 words
A process as claimed in claim 1, wherein said thin layer of said polyimide solution is in the form of a flat film, a hollow fiber, or a tube.
Claim 21
Dependent Claim
24 words
A process as claimed in claim 1, wherein said thin layer of said polyimide solution has a thickness of from 10 to 500 microns.
Claim 22
Dependent Claim
30 words
A process as claimed in claim 1, wherein a portion of said solvent is evaporated from a surface of said thin layer of said polyimide solution, before said coagulating operation.
Claim 23
Dependent Claim
51 words
A process as claimed in claim 1, wherein said coagulating liquid consists of a mixture of one part of weight of water and 0.2 to 10 parts by weight of at least one member selected from said lower aliphatic alcohols, lower aliphatic ketones, ether type compounds, amide type compounds and dimethylsulfoxide.
Claim 24
Dependent Claim
18 words
A process as claimed in claim 1, wherein said coagulating liquid has a temperature not exceeding 80° C.
Claim 25
Dependent Claim
44 words
A process as claimed in claim 1, wherein said coagulated polyimide membrane is washed with at least one member selected from the group consisting of lower aliphatic alcohols having 1 to 5 carbon atoms and lower aliphatic ketones having 3 to 5 carbon atoms.
Claim 26
Dependent Claim
28 words
A process as claimed in claim 1 or 24, wherein said membrane is heat-treated with a hot polar solvent at a temperature of from 50° to 150° C.
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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) | 1986-03-28 | 1986-09-27 | 1987-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-28 | 1990-09-27 | 1991-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-28 | 1994-09-27 | 1995-03-29 | $7700.00 | Window Closed / Lapsed |