US4778596A
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Semipermeable encapsulated membranes, process for their manufacture and their use
Assignee: Membrane Products Kiryat Weizmann Ltd
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Filing: 1986-08-18
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Granted: 1988-10-18
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Expires: 2006-08-18
Abstract
Abstract Semipermeable membranes of a porous polymeric substrate whose external and all internal surfaces (pores) are encapsulated by a semipermeable thin film of a hydrophilic polymer are provided. The encapsulating film consists of at least one layer of said polymer which is cross-linked/stabilized by polyfunctional compounds containing at least two functional (reactive) groups. The membrane substrate is optionally pretreated--before the encapsulation step--with polyfunctional compounds. The new membranes can be used in ultrafiltration and reverse osmosis processes. They are solvent-, pressure- and temperature-resistant and show good separation capacities, e.g. for separating organic compounds from salt solutions.
Inventors
- 👤 Charles Linder
- 👤 Gershon Aviv
- 👤 Mordechai Perry
- 👤 Reuven Kotraro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:58
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0088; B01D69/00; B01D69/12; B01D69/125; B01D71/00; B01D71/06; B01D71/58; B01D71/60; B01D71/601
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
57 words
An encapsulated semipermeable membrane constructed for ultrafiltration and reverse osmosis, comprising a polymeric substrate and a thin semipermeable film obtained by coating onto the external surface and all accessible internal surfaces of the substrate at least one layer of a cross-linkable hydrophilic polymer, and cross-linking the layer with a polyfunctional compound containing at least two functional groups.
Claim 2
Dependent Claim
57 words
An encapsulated semipermeable membrane constructed for ultrafiltration and reverse osmosis, comprising a polymeric substrate and a thin semipermeable film obtained by coating onto the external surface and all accessible internal surfaces of the substrate at least one layer of a cross-linkable hydrophilic polymer, and cross-linking the layer with a polyfunctional compound containing at least two functional groups.
Claim 3
Dependent Claim
21 words
A membrane according to claim 1, wherein the substrate is pretreated with a polyfunctional compound containing at least two functional groups.
Claim 4
Dependent Claim
56 words
A membrane according to claim 1, wherein the thin semipermeable film is prepared by (a) depositing at least one layer of a cross-linkable hydrophilic non-ionic polymer onto the substrate, and (b) cross-linking the layer with at least one polyfunctional compound containing at least two functional groups, at least one of the polyfunctional compounds containing ionic groups.
Claim 5
Dependent Claim
29 words
A membrane according to claim 3, wherein the layer of the cross-linkable hydrophilic non-ionic polymer is cross-linked with non-ionic and ionic polyfunctional compounds containing at least two functional groups.
Claim 6
Dependent Claim
28 words
A membrane according to claim 3, wherein the layer of the cross-linkable hydrophilic non-ionic polymer is cross-linked in either order with an ionic and a non-ionic polyfunctional compound.
Claim 7
Dependent Claim
29 words
A membrane according to claim 3, wherein the layer of the cross-linkable hydrophilic non-ionic polymer is cross-linked with two different ionic, polyfunctional compounds having the same or opposite charges.
Claim 8
Dependent Claim
17 words
A membrane according to claim 6, wherein the layer is additionally cross-linked with a non-ionic polyfunctional compound.
Claim 9
Dependent Claim
48 words
A membrane according to claim 1, wherein the thin semipermeable film is prepared by (a) depositing at least one layer of a cross-linkable hydrophilic, ionic groups containing polymer onto the substrate, and (b) cross-linking the layer with at least one polyfunctional compound containing at least two functional groups.
Claim 10
Dependent Claim
34 words
A membrane according to claim 8 wherein the layer of the cross-linkable hydrophilic, ionic groups containing polymer is cross-linked with polyfunctional compounds selected from the group consisting of non-ionics, ionics and mixtures of both.
Claim 11
Dependent Claim
36 words
A membrane according to claim 8, wherein the layer of the cross-linkable, hydrophilic, ionic-groups containing polymer is cross-linked with an ionic polyfunctional compound whose charges are opposite to those of the ionic groups of the polymer.
Claim 12
Dependent Claim
21 words
A membrane according to claim 8 wherein the cross-linkable, hydrophilic polymer is an amphoteric one cross-linked with an anionic polyfunctional compound.
Claim 13
Dependent Claim
58 words
A membrane according to claim 1, wherein the thin semipermeable film is prepared by (a) treating the substrate with a polyfunctional compound containing at least two functional groups, (b) depositing at least one layer of a cross-linkable hydrophilic polymer onto the substrate, and (c) cross-linking it with at least two polyfunctional compounds containing at least two functional groups.
Claim 14
Dependent Claim
44 words
A membrane according to claim 12, wherein the substrate is treated with ionic or non-ionic polyfunctional compounds, then a cross-linkable, hydrophilic polymer is deposited onto the substrate and cross-linked in either order with anionic or non-ionic polyfunctional compound containing at least two functional groups.
Claim 15
Dependent Claim
38 words
A membrane according to claim 1, wherein two or three layers of the cross-linkable, hydrophilic polymer are deposited onto the substrate and each layer is cross-linked with at least one polyfunctional compound containing at least two functional groups.
Claim 16
Dependent Claim
42 words
A membrane according to claim 14, wherein two layers of the cross-linkable, hydrophilic polymer are deposited onto the substrate and each layer is cross-linked with at least one polyfunctional compound selected from the group consisting of ionics, non-ionics and mixtures of both.
Claim 17
Dependent Claim
28 words
A membrane according to claim 1, wherein the substrate comprises at least one member of the group consisting of cellulosics, polyacrylonitriles, aromatic polysulfones, polyamides, polyvinylidene fluorides and polytetrafluoroethylenes.
Claim 18
Dependent Claim
22 words
A membrane according to claim 1, wherein the cross-linkable hydrophilic polymer contains active hydrogen atoms bonded to nitrogen, oxygen or sulfur atoms.
Claim 19
Dependent Claim
54 words
A membrane according to claim 17, wherein the cross-linkable, hydrophilic polymer comprises homo- or copolymers of at least one member of the group consisting of polyethyleneimines, polyvinylalcohols, cellulose derivatives, polyvinylamines, polyvinylanilines, polypiperidines, polydiallylamines, amino modified epoxides and amino modified polyepihalohydrines, or amphoteric polymers with reactive hydrogen atoms bonded to nitrogen, oxygen or sulfur atoms.
Claim 20
Dependent Claim
50 words
A membrane according to claim 1, wherein the polyfunctional compounds contain at least two functional groups selected from the group consisting of multiple unsaturated bonds, epoxide, aziridine, aldehyde, imidate, isocyanate, isothiocyanate, hydroxyl, carboxylic acid, carboxylic anhydride, carboxylic halide, cyclic carbonic acid imide halide moieties, detachable tertiary amine, and detachable anions.
Claim 21
Dependent Claim
29 words
A membrane according to claim 19, wherein the polyfunctional compounds are non-ionic and selected from the group consisting of cyclic carbonic acid imide halides, and compounds containing epoxide groups.
Claim 22
Dependent Claim
28 words
A membrane according to claim 20, wherein the non-ionic polyfunctional compounds are selected from the group consisting of halogenodiazines, triazines, and epoxides containing at least two functional substituents.
Claim 23
Dependent Claim
23 words
A membrane according to claim 19, wherein the polyfunctional compounds are ionic and selected from the group consisting of colorless halotriazines and halopyrimidines.
Claim 24
Dependent Claim
34 words
A membrane according to claim 19, wherein the polyfunctional compounds are ionic reactive azo containing ionic groups selected from the group consisting of sulfonic acid groups, carboxylic acid groups, ammonium groups, and mixtures thereof.
Claim 25
Dependent Claim
51 words
A membrane according to claim 23, wherein the polyfunctional compound is a reactive azo dyestuff containing ionic groups selected from the groups consisting of sulfonic acid (--SO 3 H) and carboxylic (--COOH) groups and reactive groups selected from the group consisting of monochlorotriazinyl, dichlorotriazinyl, 2,4-dichloropyrimidinyl, vinyl sulfonyl, β-sulfatoethylsulfonyl, β-chloroethylsulfonyl, and β-sulfatoethylaminosulfonyl.
Claim 26
Dependent Claim
58 words
A process for the manufacture of an encapsulated semipermeable membrane according to claim 1, which comprises depositing onto a semipermeable polymeric substrate from an aqueous system at least one layer of a cross-linkable, hydrophilic polymer, and cross-linking the layer by penetrating it with an aqueous preparation of at least one polyfunctional compound containing at least two functional groups.
Claim 27
Dependent Claim
26 words
A process according to claim 25, which comprises depositing the polymer on a substrate being pretreated with a polyfunctional compound containing at least two functional groups.
Claim 28
Dependent Claim
48 words
A process according to claim 25, which comprises depositing onto the substrate at least one layer of a cross-linkable, hydrophilic, non-ionic polymer and cross-linking the layer with at least one polyfunctional compound containing at least two functional groups, at least one of the polyfunctional compounds containing ionic groups.
Claim 29
Dependent Claim
45 words
A process according to claim 27, which comprises depositing onto the substrate an aqueous solution containing 0.1 to 80% by weight of the cross-linkable hydrophilic polymer, and cross-linking the polymer with an ionic and a non-ionic polyfunctional compound each containing at least two functional groups.
Claim 30
Dependent Claim
40 words
A process according to claim 25, which comprises depositing onto the substrate at least one layer of a cross-linkable, hydrophilic, ionic groups containing polymer and cross-linking the layer with at least one polyfunctional compound containing at least two functional groups.
Claim 31
Dependent Claim
44 words
A process according to claim 29, which comprises depositing onto the substrate an aqueous solution containing 0.1 to 80% by weight of a cross-linkable hydrophilic polymer, containing ionic groups, and cross-linking the polymer with a non-ionic polyfunctional compound containing at least two functional groups.
Claim 32
Dependent Claim
43 words
A process according to claim 25, which comprises treating the substrate with a polyfunctional compound containing at least two functional groups, depositing onto said substrate a cross-linkable hydrophilic polymer and cross-linking the layer with a polyfunctional compound containing at least two functional groups.
Claim 33
Dependent Claim
55 words
A process according to claim 31, which comprises treating the substrate with an aqueous solution of a polyfunctional compound, containing at least two functional groups, depositing an aqueous solution containing 0.1 to 80% by weight of the cross-linkable, hydrophilic polymer which is then cross-linked with a polyfunctional compound each containing at least two functional groups.
Claim 34
Dependent Claim
49 words
A process according to claim 25, which comprises depositing onto the substrate an aqueous solution containing 0.1 to 80% by weight of the cross-linkable, hydrophilic polymer, cross-linking the polymer with at least one polyfunctional compound containing at least two functional groups and repeating these two steps once or twice.
Claim 35
Dependent Claim
30 words
A process according to claim 25, wherein the polyfunctional compounds containing at least two functional groups are applied from aqueous solutions containing 0.05 to 5% by weight of these compounds.
Claim 36
Dependent Claim
74 words
A reverse osmosis/ultrafiltration process for treating aqueous solutions of solutes of different chemical species having a certain osmostic pressure comprising the steps of: (a) disposing the aqueous solution on one side of the membrane of claim 1, (b) filtering said solution through said membrane by applying a hydraulic pressure to the aqueous solution greater than its osmotic pressure, and (c) collecting the resulting permeate and impermeate fractions from the two sides of said membrane.
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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) | 1991-10-18 | 1992-04-18 | 1992-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-18 | 2000-04-18 | 2000-10-18 | $7700.00 | Window Closed / Lapsed |