US4068387A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solvent drying of cellulose ester membranes
Assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Filing: 1976-07-06
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Granted: 1978-01-17
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Expires: 1996-07-06
Abstract
Abstract Process for drying a water-wet permselective cellulose ester membrane by contacting the membrane with a single water replacement liquid and vaporizing the liquid from the membrane.
Inventors
- 👤 Philip Manos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:51
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0095
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
99 words
A process for drying water-wet, semipermeable cellulose ester membrane by contacting the membrane at a temperature of about from 0° to 50° C with volatile solvent having a boiling point below about 175° C to substantially completely remove water from the membrane, the volatile solvent (a) being inert to the membrane and the membrane wetting liquid and having (b) a solubility parameter not greater than about 8.4 cal. 1/2 cc. -3/2 and (c) a hydrogen bonding component of the solubility parameter not greater than about 2.5 cal. 1/2 cc. -3/2 ; and vaporizing the volatile solvent from the membrane.
Claim 2
Dependent Claim
99 words
A process for drying water-wet, semipermeable cellulose ester membrane by contacting the membrane at a temperature of about from 0° to 50° C with volatile solvent having a boiling point below about 175° C to substantially completely remove water from the membrane, the volatile solvent (a) being inert to the membrane and the membrane wetting liquid and having (b) a solubility parameter not greater than about 8.4 cal. 1/2 cc. -3/2 and (c) a hydrogen bonding component of the solubility parameter not greater than about 2.5 cal. 1/2 cc. -3/2 ; and vaporizing the volatile solvent from the membrane.
Claim 3
Dependent Claim
16 words
A process of claim 1 wherein the volatile solvent is selected from aliphatic hydrocarbons and halocarbons.
Claim 4
Dependent Claim
16 words
A process of claim 2 wherein the volatile solvent is selected from 1,1,2-trichloro-1,2,2-trifluoroethane, n-hexane and n-heptane.
Claim 5
Dependent Claim
12 words
A process of claim 1 wherein the cellulose ester is cellulose acetate.
Claim 6
Dependent Claim
18 words
A process of claim 1 wherein the water is removed from the membrane in a substantially continuous manner.
Claim 7
Dependent Claim
27 words
A process of claim 1 wherein the water in the membrane is substantially completely removed by replacement of the volatile solvent with which the membrane is contacted.
Claim 8
Dependent Claim
38 words
A process of claim 6 wherein an azeotrope of water and the volatile solvent is removed from contact with the membrane, the water removed from the azeotrope, and the resulting volatile solvent returned to contact with the membrane.
Claim 9
Dependent Claim
16 words
A process of claim 7 wherein the water is removed from the azeotrope by azeotropic distillation.
Claim 10
Dependent Claim
14 words
A process of claim 1 wherein the volatile solvent further comprises a water adsorbent.
References Cited (Backward Citations)
US1846474A
Cited
US3710945A
Cited
US3592672A
Cited
US3732627A
Cited
US3842515A
Cited
US3962798A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |