US4073724A
Expired / Lapsed
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Anisotropic phenolic polyether membrane
Assignee: Rhone Poulenc SA
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Filing: 1974-02-22
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Granted: 1978-02-14
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Expires: 1994-02-22
Abstract
Abstract Anisotropic membranes particularly useful in reverse osmosis because of their good salt rejection properties and high transmission rate are provided which consist essentially of a polymer comprising a plurality of units of the formula ##STR1## in which each of the symbols Q, Q' and Q", which can be identical or different, represents a hydrogen atom, an alkyl radical with 1 to 4 carbon atoms or a --SO 3 H radical, the number of --SO 3 H radicals in the polymer being such that the ionic capacity of the polymer is from about 0.5 to about 5 meg/g, in the form of a layer which exhibits a degree of salt rejection, said layer having an equivalent thickness of from about 0.01 to about 5μ , and a highly porous support layer, of thickness up to about 1 mm.
Inventors
- 👤 Robert Chapurlat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:27
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/20; C08J5/22; C08J5/2206; C08J5/2218; C08J5/2256; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/00091; B01D69/00; B01D69/02; B01D71/00; B01D71/06; B01D71/52; B01D2323/00; B01D2323/12; B01D2325/00; B01D2325/02; B01D2325/022; B01D2325/0283; C08J2371/00; C08J2371/08; C08J2371/10; C08J2371/12; Y; Y10; Y10S; Y10S525/00; Y10S525/905
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
121 words
A reverse osmosis membrane which consists essentially of a polymer comprising a plurality of units of the formula: ##STR4## in which each of the symbols Q, Q' and Q", which can be identical or different, represents a hydrogen atom, an alkyl radical with 1 to 4 carbon atoms or a --SO 3 H radical, the number of --SO 3 H radicals in the polymer being such that the ionic capacity of the polymer is from about 0.5 to about 5 meq/g, in the form of a layer which exhibits a degree of salt rejection, said layer having an equivalent thickness of from about 0.01 to about 5 μ, and a highly porous support layer, of thickness up to about 1 mm.
Claim 2
Dependent Claim
121 words
A reverse osmosis membrane which consists essentially of a polymer comprising a plurality of units of the formula: ##STR4## in which each of the symbols Q, Q' and Q", which can be identical or different, represents a hydrogen atom, an alkyl radical with 1 to 4 carbon atoms or a --SO 3 H radical, the number of --SO 3 H radicals in the polymer being such that the ionic capacity of the polymer is from about 0.5 to about 5 meq/g, in the form of a layer which exhibits a degree of salt rejection, said layer having an equivalent thickness of from about 0.01 to about 5 μ, and a highly porous support layer, of thickness up to about 1 mm.
Claim 3
Dependent Claim
27 words
A membrane according to claim 1, in which the polymer is a sulphonated poly(2,6-dimethyl-1,4-phenylene ether), having an ionic capacity of from about 0.8 to about 3 meq/g.
Claim 4
Dependent Claim
41 words
A membrane according to claim 1, in which the polymer has a specific viscosity of from about 0.3 to about 1.5 (measured at 25° C as a 5g/litre solution of a mixture of equal parts by weight of chloroform and methanol).
Claim 5
Dependent Claim
21 words
A membrane according to claim 1, in which the pores represent 50 to 90% of the total volume of the membrane.
Claim 6
Dependent Claim
83 words
Process for the preparation of a membrane as defined in claim 1 which comprises the following steps, in sequence: (a) casting, on a support, a solution comprising: the said polymer, two solvents for the polymer, with substantially different boiling points, and a non-solvent for the polymer with a boiling point substantially higher than that of the most volatile solvent, (b) removing at least a part of the most volatile solvent, and (c) treating the film thus produced with a non-solvent for the polymer.
Claim 7
Dependent Claim
33 words
Process according to claim 5, in which the least volatile solvent and the non-solvent both have a boiling point which is at least 30° C higher than that of the most volatile solvent.
Claim 8
Dependent Claim
22 words
Process according to claim 5, in which 15 to 100% by weight of the most volatile solvent is removed in step (b).
Claim 9
Dependent Claim
34 words
Process according to claim 5 in which the non-solvent in the casting solution used in step (a) represents 2 to 15% by weight based on the weight of the mixture of solvents and non-solvent.
Claim 10
Dependent Claim
36 words
Process according to claim 8, in which the most volatile solvent in the casting solution used in step (a) represents 10 to 70% by weight based on the weight of the mixture of solvents and non-solvent.
Claim 11
Dependent Claim
26 words
In a process for the desalination of salt water by reverse osmosis the improvement wherein the reverse osmosis membrane is one as defined in claim 1.
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) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |