US4239545A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cellulose derivative reverse osmosis membrane and casting solution and additive for preparing the same
Assignee: Toray Industries Inc
•
Filing: 1978-08-10
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Granted: 1980-12-16
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Expires: 1998-08-10
Abstract
Abstract Cellulose derivative reverse osmosis membrane containing tetracarboxylic acid and mono- or divalent carboxylic acid.
Inventors
- 👤 Tadahiro Uemura
- 👤 Masaru Kurihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:29
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B01D71/18; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D71/16; B01D71/22; C; C08; C08K; C08K5/00; C08K5/04; C08K5/09; C08K5/092; B29; B29K; B29K2001/00; B29K2001/08; B29K2001/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
95 words
In a casting solution for the preparation of a membrane of a cellulose derivative selected from the group consisting of cellulose ether and cellulose ester, having a good balance of membrane separation characteristics, said solution containing said cellulose derivative, and an organic water soluble solvent therefor, the improvement which comprises including a tetracarboxylic acid represented by the following formula: R--(CO.sub.2 H).sub.4 wherein R is a tetravalent aliphatic or alicyclic organic radical having from 2 to 10 carbon atoms, whereby the membrane which is prepared has not more than 0.2 voids per 0.844 mm 2 .
Claim 2
Dependent Claim
95 words
In a casting solution for the preparation of a membrane of a cellulose derivative selected from the group consisting of cellulose ether and cellulose ester, having a good balance of membrane separation characteristics, said solution containing said cellulose derivative, and an organic water soluble solvent therefor, the improvement which comprises including a tetracarboxylic acid represented by the following formula: R--(CO.sub.2 H).sub.4 wherein R is a tetravalent aliphatic or alicyclic organic radical having from 2 to 10 carbon atoms, whereby the membrane which is prepared has not more than 0.2 voids per 0.844 mm 2 .
Claim 3
Dependent Claim
34 words
The casting solution in accordance with claim 1, wherein the cellulose derivative is a member selected from the group consisting of cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, methyl cellulose and ethyl cellulose.
Claim 4
Dependent Claim
14 words
The casting solution of claim 2, wherein the cellulose derivative is a cellulose acetate.
Claim 5
Dependent Claim
31 words
The casting solution of claim 1, wherein the amount of tetracarboxylic acid is from about 1 to about 20 parts by weight per 10 parts by weight of the cellulose derivative.
Claim 6
Dependent Claim
31 words
The casting solution of claim 1, wherein the tetracarboxylic acid is selected from the group consisting of butanetetracarboxylic acid, ethylene tetracarboxylic acid, cyclopropanetetracarboxylic acid, cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid and furantetracarboxylic acid.
Claim 7
Dependent Claim
14 words
The casting solution of claim 5 wherein the tetracarboxylic acid is a 1,2,3,4-butanetetracarboxylic acid.
Claim 8
Dependent Claim
22 words
The casting solution of claim 1, which further contains a member selected from the group consisting of monocarboxylic acid and dicarboxylic acid.
Claim 9
Dependent Claim
35 words
The casting solution of claim 7, wherein the mole fraction of the member based on the total mols of the member and tetracarboxylic acid contained in the casting solution is not more than about 0.55.
Claim 10
Dependent Claim
17 words
The casting solution of claim 8, wherein said mole fraction is from about 0.20 to about 0.40.
Claim 11
Dependent Claim
14 words
The casting solution of claim 7, wherein the dicarboxylic acid is a maleic acid.
References Cited (Backward Citations)
US3673084A
Cited
US3773534A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-16 | 1984-06-16 | 1984-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-16 | 1988-06-16 | 1988-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-16 | 1992-06-16 | 1992-12-16 | $7700.00 | Window Closed / Lapsed |