US4990609A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sulfoethyl cellulose of high solution quality and a process for its production
Assignee: Dow Produktions und Vertriebs GmbH and Co OHG
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Filing: 1988-12-09
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Granted: 1991-02-05
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Expires: 2008-12-09
Abstract
Abstract Sulfoethyl cellulose prepared by addition of an alkylating agent and subsequent addition of alkali shows particularly valuable properties.
Inventors
- 👤 Dieter Herzog
- 👤 Klaus Balser
- 👤 Klaus Szablikowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:30
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/10; C08B11/193
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
47 words
In the preparation of a sulfoethyl cellulose by reacting cellulose with a sulfoethylating agent, the improvement which comprises effecting the reaction by (a) grinding the cellulose, (b) combining the ground cellulose with the sulfoethylating agent, (c) adding alkali and (d) raising the temperature to effect the reaction.
Claim 2
Dependent Claim
47 words
In the preparation of a sulfoethyl cellulose by reacting cellulose with a sulfoethylating agent, the improvement which comprises effecting the reaction by (a) grinding the cellulose, (b) combining the ground cellulose with the sulfoethylating agent, (c) adding alkali and (d) raising the temperature to effect the reaction.
Claim 3
Dependent Claim
21 words
The process according to claim 1, including the further step (e) of neutralizing, filtering and washing the product of step (d).
Claim 4
Dependent Claim
34 words
The process according to claim 1, wherein between steps (c) and (d) the combined materials of step (b) are permitted to stand for about 60 to 180 minutes from about 0° to 35° C.
Claim 5
Dependent Claim
15 words
The process according to claim 1, wherein the sulfoethylating agent is a vinyl sulfonic acid.
Claim 6
Dependent Claim
22 words
The process according to claim 1, wherein the steps (a), (b), and (c) (d) are carried out consecutively in the same vessel.
Claim 7
Dependent Claim
26 words
The process according to claim 1, wherein the cellulose is selected from the group consisting of linters, softwood sulfite cellulose, softwood sulfate cellulose and hardwood cellulose.
Claim 8
Dependent Claim
23 words
The process according to claim 1, wherein step (d) is continued for sufficient time to result in a DS-sulfoethyl of at least 0.4.
Claim 9
Dependent Claim
23 words
The process according to claim 1, wherein step (d) is continued for sufficient time to result in a DS-sulfoethyl of at least 0.5.
Claim 10
Dependent Claim
15 words
The process according to claim 1, wherein step (b) is effected in an alcohol slurry.
Claim 11
Dependent Claim
11 words
The process according to claim 9, wherein the alcohol is isopropanol.
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) | 1994-02-04 | 1994-08-06 | 1995-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-04 | 1998-08-06 | 1999-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-04 | 2002-08-06 | 2003-02-05 | $7700.00 | Window Closed / Lapsed |