US3957935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of a dry desalting cellulose acetate membrane
Assignee: Hoechst AG
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Filing: 1974-12-05
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Granted: 1976-05-18
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Expires: 1994-12-05
Abstract
Abstract This invention relates to an improvement in the process for the production of a dry cellulose acetate membrane comprising forming a sheet material from a cellulose acetate solution, treating the sheet material with a liquid and drying, the improvement comprising treating the sheet material with an aqueous solution of a polyvalent aliphatic alcohol having 2 to 4 carbon atoms for about 2 to 10 minutes at a temperature in the range of about 50° to 110°C, and drying said sheet material at a temperature not in excess of about 50°C.
Inventors
- 👤 Eberhard Staude
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:04
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0095; C; C08; C08J; C08J7/00; C08J7/02; C08J2301/00; C08J2301/08; C08J2301/10; C08J2301/12
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
86 words
In the process for the production of a dry cellulose acetate membrane comprising forming a sheet material from a cellulose acetate solution, treating the sheet material with a liquid and drying, the improvement consisting essentially of treating the sheet material with an aqueous solution of a polyvalent aliphatic alcohol having 2 to 4 carbon atoms for about 2 to 10 minutes at a temperature in the range of about 50° to 110°C, and drying said sheet material at a temperature not in excess of about 50°C.
Claim 2
Dependent Claim
86 words
In the process for the production of a dry cellulose acetate membrane comprising forming a sheet material from a cellulose acetate solution, treating the sheet material with a liquid and drying, the improvement consisting essentially of treating the sheet material with an aqueous solution of a polyvalent aliphatic alcohol having 2 to 4 carbon atoms for about 2 to 10 minutes at a temperature in the range of about 50° to 110°C, and drying said sheet material at a temperature not in excess of about 50°C.
Claim 3
Dependent Claim
14 words
A process according to claim 1 in which the polyvalent aliphatic alcohol is glycerol.
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) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |