US3620970A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reverse osmosis membranes from hydroxyalkyl derivatives of cellulose
Assignee: Hercules LLC
•
Filing: 1969-09-05
•
Granted: 1971-11-16
•
Expires: 1989-09-05
Abstract
Abstract The invention provides reverse osmosis membranes characterized by a salt-rejecting layer of a hydroxyalkyl derivative of cellulose. The membranes are useful for desalination and other processes involving reverse osmosis.
Inventors
- 👤 Eugene D Klug
- 👤 Harold M Spurlin
- 👤 William L Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:07
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D67/00; B01D67/0081; B01D67/0093; B01D67/00933; B01D69/00; B01D69/08; B01D71/22; B01D2323/00; B01D2323/30; B01D61/00; B01D61/02; B01D61/025
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
174 words
A reverse osmosis membrane consisting of a walled hollow fiber having a wall thickness of not more than 2.0 mils of a cross-linked alkoxy derivative of cellulose selected from the group consisting of A. hydroxyalkyl ethers of cellulose in which the hydroxyalkyl group contains from two to six carbon atoms; B. mixed hydroxyalkyl ethers of cellulose in which the hydroxyalkyl groups contain an average of from two to six carbon atoms; C. mixed hydroxyalkyl-alkyl And mixed hydroxyalkyl-aralkyl ethers of cellulose in which the hydroxyalkyl group contains from two to six carbon atoms and, respectively, the alkyl group contains from one to six carbon atoms and the aralkyl group contains from seven to 12 carbon atoms; and D. mixed hydroxyalkyl-aminoalkyl ethers of cellulose in which the hydroxyalkyl group contains from two to six carbon atoms and the aminoalkyl group contains from two to 10 carbon atoms; and having a degree of polymerization within the range of about 25 to 5,000 and a hydroxyalkyl M.S. of at least 1 and a D.S. of at least 2.
Claim 2
Dependent Claim
13 words
The membrane of claim 1 in which the cellulose derivative is hydroxypropyl cellulose.
Claim 3
Dependent Claim
13 words
The membrane of claim 1 in which the cellulose derivative is hydroxypropyl-hydroxybutyl cellulose.
Claim 4
Dependent Claim
13 words
The membrane of claim 2 in which the cellulose derivative is hydroxypropyl cellulose.
Claim 5
Dependent Claim
13 words
The membrane of claim 2 in which the cellulose derivative is hydroxypropyl-hydroxybutyl cellulose.
Claim 6
Dependent Claim
13 words
The membrane of claim 1 in which the cellulose derivative is hydroxyethyl cellulose.
Claim 7
Dependent Claim
13 words
The membrane of claim 2 in which the cellulose derivative is hydroxyethyl cellulose.
Claim 8
Dependent Claim
25 words
The membrane of claim 1 in which the cellulose derivative has been cross-linked by reaction with a cross-linking agent containing at least two alkylol groups.
Claim 9
Dependent Claim
24 words
The membrane of claim 1 in which the cellulose derivative has been cross-linked by reaction with a compound containing at least two isocyanate groups.
Claim 10
Dependent Claim
25 words
The membrane of claim 2 in which the cellulose derivative has been cross-linked by reaction with a cross-linking agent containing at least two alkylol groups.
Claim 11
Dependent Claim
24 words
The membrane of claim 2 in which the cellulose derivative has been cross-linked by reaction with a compound containing at least two isocyanate groups.
Claim 12
Dependent Claim
22 words
The membrane of claim 1 in which the cellulose derivative has been cross-linked to give a cross-link gradient across the film thickness.
Claim 13
Dependent Claim
22 words
The membrane of claim 2 in which the cellulose derivative has been cross-linked to give a cross-link gradient across the film thickness.
Claim 14
Dependent Claim
21 words
The membrane of claim 1 in which successive layers of cellulosic derivatives are cast and cross-linked to give a multilayer membrane.
Claim 15
Dependent Claim
21 words
The membrane of claim 2 in which successive layers of cellulosic derivatives are cast and cross-linked to give a multilayer membrane.
Claim 16
Dependent Claim
39 words
The process of desalinating water which comprises contacting saline water under pressure with the membrane of claim 1 whereby water molecules are caused to pass through the membrane while the salt ions are rejected from passing through the membrane.
Claim 17
Dependent Claim
39 words
The process of desalinating water which comprises contacting saline water under pressure with the membrane of claim 2 whereby water molecules are caused to pass through the membrane while the salt ions are rejected from passing through the membrane.
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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |