EP0142973A2
Expired / Lapsed
EP
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Membranes
Assignee: Imperial Chemical Industries Ltd
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Filing: 1984-11-12
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Granted: —
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Expires: 2004-11-12
Abstract
Abstract Solutions of sulphonated polyarylethersulphones in a solvent mixture of at least three liquids which are non-solvents or poor solvents for the polymer, can be used to produce asymmetric semipermeable membranes. The polymer may be a copolymer of and wherein Ph 1 and Ph 2 are respectively unsulphonated and sulphonated phenylene residues. The components of the solvent mixture have specified solubility parameters. Suitable solvent mixtures include water, 1,4 -dioxane and acetonitrile and also methanol, chloroform and nitromethane.
Inventors
- 👤 Richard Anthony Hann
- 👤 David Robert Holmes
- 👤 John William Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 06:01
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/09; C08J3/091; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D67/0016; B01D67/00165; B01D69/00; B01D69/02; B01D71/00; B01D71/06; B01D71/66; B01D71/68; B01D2323/00; B01D2323/08; B01D2323/081; B01D2325/00; B01D2325/02; B01D2325/022; C08J2381/00; C08J2381/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
196 words
A solution of a sulphonated polyarylethersulphone in a solvent mixture, wherein the sulphonated polyarylethersulphone has repeating units of the formula I and the solvent mixture contains at least three components each of which is a non-solvent or poor solvent for the sulphonated polyarylethersulphone and which are a) a liquid or a low melting solid containing at least one hydroxylic group and having a delta-H with a value of at least 8; b) a liquid or a low melting solid having a delta-D with a value of at least 8 and a delta-P with a value of not more than 3 and c) a liquid or a low melting solid having a delta-P with a value of at least 8.5 and a delta-H with a value of not more than 3; wherein Ph represents a phenylene residue wherein at least some of the groups Ph are sulphonated. n is 1 or 2 and the value of n can differ along the polymer chain; the solvent mixture forms a single liquid phase and none of the components of the solvent mixture reacts or complexes with another of the components of the solvent mixture or with the sulphonated polyarylethersulphone.
Claim 2
Dependent Claim
196 words
A solution of a sulphonated polyarylethersulphone in a solvent mixture, wherein the sulphonated polyarylethersulphone has repeating units of the formula I and the solvent mixture contains at least three components each of which is a non-solvent or poor solvent for the sulphonated polyarylethersulphone and which are a) a liquid or a low melting solid containing at least one hydroxylic group and having a delta-H with a value of at least 8; b) a liquid or a low melting solid having a delta-D with a value of at least 8 and a delta-P with a value of not more than 3 and c) a liquid or a low melting solid having a delta-P with a value of at least 8.5 and a delta-H with a value of not more than 3; wherein Ph represents a phenylene residue wherein at least some of the groups Ph are sulphonated. n is 1 or 2 and the value of n can differ along the polymer chain; the solvent mixture forms a single liquid phase and none of the components of the solvent mixture reacts or complexes with another of the components of the solvent mixture or with the sulphonated polyarylethersulphone.
Claim 3
Dependent Claim
92 words
A solution as claimed in claim 1 in which component (a) of the solvent mixture has a delta-H of at least 8, a delta-D of not more than 8 and a delta-P of at least 6; component (b) of the solvent mixture has a delta-D of at least 8, a delta-P of not more than 3 and a delta-H of not more than 4; and component (c) of the solvent mixture has a delta-P of at least 8.5 a delta-H of not more than 3 and a delta-D of at least 7.5.
Claim 4
Dependent Claim
27 words
A solution as claimed in claim 1 or 2 wherein the solvent mixture consists of water, 1,4 -dioxane and acetonitrile or consists of methanol, chloroform and nitromethane.
Claim 5
Dependent Claim
48 words
A solution as claimed in claim 3 wherein the solvent mixture consists of 10 to 25% by weight of water, 10 to 50X by weight of acetonitrile and 25 to 66% by weight of 1,4 -dioxane, the total amounts of the three components aggregating to 100% by weight.
Claim 6
Dependent Claim
35 words
A solution as claimed in any one of claims 1 to 4 wherein at least one component of the solvent mixture is volatile and at least partially evaporates when casting a film from the solution.
Claim 7
Dependent Claim
111 words
A solution as claimed in any one of claims 1 to 5 wherein the sulphonated polyarylethersulphone is a material having repeat units of the formula together with repeat units of the formula and optionally units of the formula wherein Ph represents a phenylene residue; Ph 2 represents a phenylene residue having one or two groups - SO 3 M; M is a hydrogen atom, a metal atom and/or a group NR 4 , wherein the groups M may be the same or different and the proportion of the groups M is sufficient to combine with the unsatisfied valencies of the group - S0 3 ; and R is an alkyl group;
Claim 8
Dependent Claim
54 words
A solution as claimed in claim 6 wherein the sulphonated polyarylethersulphone is the product of sulphonating a copolymer containing from 5 to 80 mole % of units IV and correspondingly from 95 to 20 mole % of units III and sulphonating to convert at least 90X of the units IV to the units II.
Claim 9
Dependent Claim
37 words
A solution as claimed in any one of claims 1 to 7 wherein the sulphonated polyarylethersulphone has a molecular weight which is such that the polymer has a reduced viscosity of at least 0.2 up to 2.5.
Claim 10
Independent Claim
81 words
A method for the production of an asymmetric semi-permeable membrane which method comprises forming a solution of a sulphonated polyarylethersulphone in a solvent mixture, casting the solution on a support to form a film on the support, immersing, in a coagulation bath, the cast film of the solution on the support and recovering a membrane from the coagulation bath, wherein the solution of the sulphonated polyarylethersulphone in the solvent mixture is as claimed in any one of claims 1 to 8.
Claim 11
Dependent Claim
36 words
A method as claimed in claim 9 wherein the supported liquid film is exposed to the atmosphere for a time of from 10 seconds to 5 minutes, before immersing the supported film in the coagulation bath.
Claim 12
Dependent Claim
29 words
A method claimed in either claim 9 or claim 10 wherein the coagulation bath contains a non-solvent liquid or liquid mixture or an aqueous solution of a metal salt.
Claim 13
Independent Claim
37 words
A method as claimed in any one of claims 9 to 11 wherein the recovered membrane is heat treated by immersion -in an aqueous solution of an inorganic salt at a temperature of from 70°C to 150°C.
Claim 14
Dependent Claim
24 words
An asymmetric semi-permeable membrane of thickness 50 up to 250 micrometres whenever obtained by the method of any one of claims 9 to 12.
Claim 15
Dependent Claim
46 words
A process for the desalination of sea water or for the purification of brackish waters or industrial effluents by effecting reverse osmosis or ultrafiltration using a membrane as claimed in claim 13 or as obtained by the process of any one of claims 9 to 12.
References Cited (Backward Citations)
No citation records indexed.
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