US4341892A
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Preparation of alkali cellulose having a low water content
Assignee: Henkel AG and Co KGaA
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Filing: 1981-03-13
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Granted: 1982-07-27
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Expires: 2001-03-13
Abstract
Abstract This invention is directed to the preparation of alkali cellulose. More particularly, this invention is directed to a process for the preparation of alkali cellulose having a low water content, wherein finely divided cellulose suspended in a typical inert organic solvent is presteeped and the cellulose suspension is contacted with an alkali metal hydroxide/alcohol mixture and at least one aqueous alkalization solution of different concentration.
Inventors
- 👤 Norbert Kuhne
- 👤 Hasso Leischner
- 👤 Wilfried Rahse
- 👤 Willi Wust
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:32
CPC Classifications
C; C08; C08B; C08B1/00; C08B1/08
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
51 words
A process for the preparation of alkali cellulose having a low water content, wherein finely divided cellulose suspended in an inert organic solvent is presteeped with an alkali metal hydroxide and optionally an alcohol and the presteeped suspension is contacted with an aqueous alkali metal hydroxide alkalization solution of different concentration.
Claim 2
Dependent Claim
51 words
A process for the preparation of alkali cellulose having a low water content, wherein finely divided cellulose suspended in an inert organic solvent is presteeped with an alkali metal hydroxide and optionally an alcohol and the presteeped suspension is contacted with an aqueous alkali metal hydroxide alkalization solution of different concentration.
Claim 3
Dependent Claim
14 words
The process of claim 1, wherein cellulose of beech, spruce or linters is used.
Claim 4
Dependent Claim
12 words
The process of claim 2, wherein the cellulose is short-fibered or powdered.
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein the alcohol is a lower aliphatic alcohol with from 1 to 4 carbon atoms.
Claim 6
Dependent Claim
10 words
The process of claim 4, wherein the alcohol is methanol.
Claim 7
Dependent Claim
35 words
The process of claim 1, wherein first a from about 65 to 100 percent sodium hydroxide solution and then a from about 15 to 60 percent aqueous sodium hydroxide solution are used as alkalization agents.
Claim 8
Dependent Claim
21 words
The process of claim 1, wherein the inert organic solvent is an aliphatic hydrocarbon having from 6 to 12 carbon atoms.
Claim 9
Dependent Claim
17 words
The process of claim 7, wherein the inert organic solvent is toluene, cyclohexane, xylene, octane, or decane.
Claim 10
Dependent Claim
20 words
The process of claim 1, wherein during the presteeping stage solid alkali metal hydroxide is added to the cellulose suspension.
Claim 11
Dependent Claim
27 words
The process of claim 9, wherein the molar ratio of solid alkali metal hydroxide to alkali metal hydroxide in aqueous solution is from about 0.01 to 3.5:1.
Claim 12
Dependent Claim
15 words
The process of claim 10, wherein the molar ratio is from about 0.2 to 1.2:1.
Claim 13
Dependent Claim
16 words
The process of claim 10, wherein the alkali metal hydroxide in each instance is sodium hydroxide.
Claim 14
Dependent Claim
59 words
The process for the preparation of alkali cellulose having a low water content according to claim 1, wherein a suspension of finely divided cellulose in an inert organic solvent to which solid sodium hydroxide and then optionally an alcohol have been added, is presteeped, and the presteeped suspension is contacted with an aqueous sodium hydroxide solution of different concentration.
Claim 15
Dependent Claim
44 words
The process of claim 13, wherein the solid sodium hydroxide and the alcohol comprise a from about 65 to 100 percent by weight sodium hydroxide solution and the aqueous sodium hydroxide solution comprises from about 15 to 60 percent by weight of sodium hydroxide.
References Cited (Backward Citations)
CA546634A
Cited
GB543301A
Cited
GB611081A
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US2680737A
Cited
US2767170A
Cited
US2680738A
Cited
DE1468226A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-26 | 1986-01-25 | 1986-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-26 | 1990-01-25 | 1990-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-26 | 1994-01-25 | 1994-07-27 | $7700.00 | Window Closed / Lapsed |