US4619767A
Expired / Lapsed
US
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Composite semipermeable membrane
Assignee: Nitto Denko Corp
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Filing: 1981-07-28
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Granted: 1986-10-28
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Expires: 2001-07-28
Abstract
Abstract A composite semipermeable membrane is described, wherein said membrane comprises (1) a porous substrate, (2) an ultrathin film as a surface layer formed by polymerization by crosslinking of polyvinyl alcohol and an amino compound having at least two secondary amino groups using a polyfunctional crosslinking reagent capable of reacting with secondary amino groups and hydroxyl groups, and (3) a porous inner layer composed of water insoluble polyvinyl alcohol which is present between the porous substrate and the ultrathin film.
Inventors
- 👤 Yoshiyasu Kamiyama
- 👤 Noriaki Yoshioka
- 👤 Keisuke Nakagome
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:12
CPC Classifications
B; B32; B32B; B32B5/00; B32B5/18; B01; B01D; B01D69/00; B01D69/12; B01D69/125; B01D69/1251; B01D71/00; B01D71/06; B01D71/38; B01D71/381; B32B27/00; B32B27/18; B32B27/28; B32B27/286; B32B27/30; B32B27/304; B32B27/306; B32B27/32; B32B2250/00; B32B2250/03; B32B2250/24; B32B2266/00; B32B2266/02; B32B2266/0214; B32B2266/0221; B32B2266/0235; B32B2266/0242; B32B2266/025; B32B2305/00; B32B2305/02; B32B2305/026; B32B2329/00; B32B2329/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
73 words
A composite semipermeable membrane comprising (1) a porous substrate, (2) an ultrathin film as a surface layer formed by polymerization by crosslinking of polyvinyl alcohol and an amino compound having at least two secondary amino groups using a polyfunctional crosslinking reagent capable of reacting with secondary amino groups and hydroxyl groups, and (3) a porous inner layer composed of water-insoluble polyvinyl alcohol which is present between the porous substrate and the ultrathin layer.
Claim 2
Dependent Claim
73 words
A composite semipermeable membrane comprising (1) a porous substrate, (2) an ultrathin film as a surface layer formed by polymerization by crosslinking of polyvinyl alcohol and an amino compound having at least two secondary amino groups using a polyfunctional crosslinking reagent capable of reacting with secondary amino groups and hydroxyl groups, and (3) a porous inner layer composed of water-insoluble polyvinyl alcohol which is present between the porous substrate and the ultrathin layer.
Claim 3
Dependent Claim
64 words
A composite semipermeable membrane according to claim 1 wherein said amino compound is represented by formula (I) R.sup.1 --NH--A--NH--R.sup.2 (I) wherein A represents an alkylene group having from 2 to 8 carbon atoms, a divalent alicyclic group, a divalent aromatic group, or a divalent heteroaromatic group, and R 1 and R 2 each represents an alkyl group having from 1 to 3 carbon atoms.
Claim 4
Dependent Claim
61 words
A composite semipermeable membrane according to claim 1 wherein said amino compound is represented by formula (II) ##STR7## wherein R 3 represents an alkylene group having from 0 to 4 carbon atoms, R 4 and R 5 each represents an alkyl group having from 1 to 3 carbon atoms, and i and j each represents an integer of 0 to 4.
Claim 5
Dependent Claim
56 words
A composite semipermeable membrane according to claim 1 wherein said amino compound is represented by formula (III) ##STR8## wherein R 6 and R 7 each represents an alkyl group having from 1 to 3 carbon atoms, k and l each represents an integer of 0 to 4, and m represents an integer of 0 to 4.
Claim 6
Dependent Claim
46 words
A composite semipermeable membrane according to claim 1 wherein said amino compound is represented by formula (IV) ##STR9## wherein R 8 represents an alkyl group having from 1 to 3 carbon atoms, n represents 1 or 2, and p represents an integer of 0 to 4.
Claim 7
Dependent Claim
40 words
A composite semipermeable membrane according to claim 1, 2, 3, 4, or 5, wherein said polyfunctional crosslinking reagent has 2 or more functional groups selected from acid halide groups, N-haloformyl groups, haloformate groups, halogen sulfonyl groups and acid anhydride groups.
Claim 8
Dependent Claim
28 words
A composite semipermeable membrane according to claim 1, 2, 3, 4, or 5, wherein said porous substrate is composed of polysulfone, polyacrylonitrile, cellulose ester, polypropylene or polyvinyl chloride.
Claim 9
Dependent Claim
55 words
A composite semipermeable membrane according to claim 1, 2, 3, 4, or 5, wherein the porous substrate has a surface pore size of from 50 to 500 Å and has a pure water flux of at least 10 -5 g/cm 2 -second-atmosphere after operation for one hour under a pressure of 3.5 kg/cm 2 .
Claim 10
Dependent Claim
38 words
A composite semipermeable membrane according to claim 1, wherein said polyvinyl alcohol is a water soluble polymer having a saponification value of from 87 to 99 mole % and a degree of polymerization of from 300 to 3000.
Claim 11
Dependent Claim
21 words
A composite semipermeable membrane according to claim 9, wherein said ultrathin film has a thickness of from 50 to 800 Å.
References Cited (Backward Citations)
US3951815A
Cited
US4337154A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-27 | 1990-04-28 | 1990-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-27 | 1994-04-28 | 1994-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-27 | 1998-04-28 | 1998-10-28 | $7700.00 | Window Closed / Lapsed |