Patent US5581997A successfully refreshed from Google Patents.
Patent US3694902A successfully refreshed from Google Patents.
Patent US4385084A successfully refreshed from Google Patents.
US4385084A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing a selective permeable membrane
Assignee: Nitto Denko Corp
•
Filing: 1980-05-19
•
Granted: 1983-05-24
•
Expires: 2000-05-19
Abstract
Abstract A process is described for preparing a selective permeable membrane comprising coating a solution consisting essentially of (i) a polyimide polymer consisting essentially of a repeating unit of the formula (I): ##STR1## wherein R 1 is a divalent organic group, (ii) a swelling agent selected from the group of compounds represented by formula (II) and (III): R.sup.3 O----CH.sub.2 CHR.sup.2 O).sub.n R.sup.4 (II) R.sup.5 ----OH).sub.m (III) wherein R 2 , R 3 and R 4 , which may be the same or different, can be hydrogen, a methyl group, or an ethyl group, and when R 2 is hydrogen, n can be an integer of from 1 to 5, and when R 2 is a methyl or ethyl group, n can be an integer of from 1 to 3, R 5 is a saturated aliphatic hydrocarbon group containing 3 to 6 carbon atoms, and m can be an integer of from 2 to 6, and (iii) an organic solvent, on a supporting substrate, and immersing the solution coated supporting substrate in a coagulating liquid which does not dissolve the polyimide polymer and is miscible with the organic solvent, to coagulate the polyimide polymer and form the membrane. Membranes prepared by the process are also described.
Inventors
- 👤 Akio Iwama
- 👤 Yoshiyasu Kamiyama
- 👤 Yoshitaka Kazuse
- 👤 Hisashi Ichinose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:47
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; C; C08; C08L; C08L79/00; C08L79/04; C08L79/08
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
208 words
A process for preparing a selective permeable membrane which is suitable for use in the separation of organic liquid mixtures comprising coating a solution consisting essentially of (i) a polyimide polymer consisting essentially of a repeating unit of the formula (I): ##STR12## wherein R 1 is a divalent organic group, (ii) at least one swelling agent selected from the group of compounds represented by formulae (II) and (III) R.sup.3 O----CH.sub.2 CHR.sup.2 O).sub.n R.sup.4 (II) R.sup.5 ----OH).sub.m (III) wherein R 2 , R 3 and R 4 , which may be the same or different, can be hydrogen, a methyl group, or an ethyl group, and when R 2 is hydrogen, n can be an integer of from 1 to 5, and when R 2 is a methyl or ethyl group, n can be an integer of from 1 to 3, R 5 is a saturated aliphatic hydrocarbon group containing 3 to 6 carbon atoms, and m can be an integer of from 2 to 6, and (iii) an organic solvent, on a supporting substrate, and immersing the solution coated supporting substrate in a coagulating liquid which does not dissolve the polyimide polymer and is miscible with the organic solvent, to coagulate the polyimide polymer and form the membrane.
Claim 2
Dependent Claim
208 words
A process for preparing a selective permeable membrane which is suitable for use in the separation of organic liquid mixtures comprising coating a solution consisting essentially of (i) a polyimide polymer consisting essentially of a repeating unit of the formula (I): ##STR12## wherein R 1 is a divalent organic group, (ii) at least one swelling agent selected from the group of compounds represented by formulae (II) and (III) R.sup.3 O----CH.sub.2 CHR.sup.2 O).sub.n R.sup.4 (II) R.sup.5 ----OH).sub.m (III) wherein R 2 , R 3 and R 4 , which may be the same or different, can be hydrogen, a methyl group, or an ethyl group, and when R 2 is hydrogen, n can be an integer of from 1 to 5, and when R 2 is a methyl or ethyl group, n can be an integer of from 1 to 3, R 5 is a saturated aliphatic hydrocarbon group containing 3 to 6 carbon atoms, and m can be an integer of from 2 to 6, and (iii) an organic solvent, on a supporting substrate, and immersing the solution coated supporting substrate in a coagulating liquid which does not dissolve the polyimide polymer and is miscible with the organic solvent, to coagulate the polyimide polymer and form the membrane.
Claim 3
Dependent Claim
21 words
A process as in claim 1, wherein said polyimide polymer has a percentage of imide units of at least about 70%.
Claim 4
Dependent Claim
20 words
A process as in claim 1, wherein said polyimide polymer has a percentage of imide units of at least 90%.
Claim 5
Dependent Claim
21 words
A process as in claim 1, wherein said polyimide polymer has a percentage of imide units of from 98 to 100%.
Claim 6
Dependent Claim
24 words
A process as in claim 1, wherein R 1 in the formula (I) is a divalent organic group containing at least one aromatic ring.
Claim 7
Dependent Claim
20 words
A process as in claim 1, wherein said polyimide polymer has a inherent viscosity of from about 0.55 to 1.00.
Claim 8
Dependent Claim
19 words
A process as in claim 1, wherein said polyimide polymer has a inherent viscosity of from 0.60 to 0.85.
Claim 9
Dependent Claim
31 words
A process as in claim 1, wherein a swelling agent represented by formula (II) is selected wherein R 2 is hydrogen and n is an integer of from 1 to 5.
Claim 10
Dependent Claim
31 words
A process as in claim 1, wherein a swelling agent represented by formula (II) is selected wherein R 2 is hydrogen and n is an integer of from 1 to 3.
Claim 11
Dependent Claim
35 words
A process as in claim 1, wherein a swelling agent represented by formula (II) is selected wherein R 2 is a methyl or ethyl group, and n is an integer of from 1 to 3.
Claim 12
Dependent Claim
12 words
A process as in claim 10, wherein n is 1 or 2.
Claim 13
Dependent Claim
53 words
A process as in claim 1, 8, 9, 10, or 11, wherein a swelling agent represented by formula (II) is selected from the group consisting of diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and mixtures thereof.
Claim 14
Dependent Claim
16 words
A process as in claim 1, wherein a swelling agent represented by formula (III) is selected.
Claim 15
Dependent Claim
33 words
A process as in claim 1 or 13, wherein a swelling agent represented by formula (III) is selected from the group consisting of glycerin, propanediol, butanediol, butanetetraol, pentaerythritol, xylitol, sortitol and mixtures thereof.
Claim 16
Dependent Claim
26 words
A process as in claim 1, 2, 3, 4, 6 or 7 wherein said organic solvent is selected from the group consisting of N-methylpyrrolidone and dimethylformamide.
Claim 17
Dependent Claim
12 words
A process as in claim 11 wherein said coagulating medium is water.
Claim 18
Dependent Claim
40 words
A process as in claim 1, 2, 3, 4, 5, 6, or 7 wherein the coating solution has a concentration of from about 5 to 30% by weight of the polyimide polymer based on the total weight of the solution.
Claim 19
Dependent Claim
20 words
A process as in claim 17 wherein the coating solution has a concentration of from 8 to 20% by weight.
Claim 20
Dependent Claim
43 words
A process as in claim 1, 2, 3, 4, 5, 6, or 7 wherein said swelling agent is present in said coating solution in an amount from about 30 to 300 parts by weight per 100 parts by weight of the polyimide polymer.
Claim 21
Dependent Claim
18 words
A process as in claim 5 wherein said R 1 is selected from the group consisting of ##STR13##
Claim 22
Dependent Claim
56 words
A process as in claim 1, 2, 3, 4, 5, 6, or 7, wherein prior to immersing the solution coated supporting substrate in the coagulating liquid, the coated substrate is heated by hot air at a temperature of from about 50° C. to 200° C. for a period of time from about 1 to 120 seconds.
Claim 23
Dependent Claim
50 words
A process as in claim 1, 2, 3, 4, 5, 6, or 7, wherein said solution contains other polymers which are miscible with the solution and have self-supporting properties, in an amount of no more than about 20 parts by weight per 100 parts by weight of the polyimide polymer.
Claim 24
Dependent Claim
32 words
A process as in claim 22, wherein said solution contains other polymers which are miscible with the solution and have self-supporting properties, in an amount no more than 5 parts by weight.
Claim 25
Dependent Claim
22 words
A process as in claim 22, wherein said other polymers are selected from the group consisting of polysulfone and polyphenylene oxide polymers.
Claim 26
Dependent Claim
29 words
A process as in claim 1, 2, 3, 4, 5, 6, or 7, wherein said other polymers are selected from the group consisting of polysulfone and polyphenylene oxide polymers.
Claim 27
Dependent Claim
39 words
A process as in claim 1, 2, 3, 4, 5, 6, or 7, wherein after said coagulation step the membrane is heat-treated at a temperature of from about 100° to 400° C. for from about 5 to 30 minutes.
Claim 28
Dependent Claim
29 words
A process as in claim 1, 2, 3, 4, 5, 6, or 7, wherein the number average molecular weight of the polyimide polymer is from about 20,000 to 120,000.
Claim 29
Dependent Claim
16 words
A process as in claim 27 wherein the molecular weight is from about 30,000 to 80,000.
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) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |