US4091205A
Expired / Lapsed
US
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Method for preparing low-substituted cellulose ethers
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1975-11-26
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Granted: 1978-05-23
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Expires: 1995-11-26
Abstract
Abstract In the process for the preparation of low-substituted cellulose ethers comprising the successive steps of etherification of alkali cellulose, neutralization of the crude cellulose ether, washing, drying and pulverization, the neutralization step is carried out in two stages, i.e., by first employing 5 to 80% of an acid stoichiometrically required and then adding an additional amount of the acid to complete neutralization. The cellulose ethers thus prepared can readily be pulverized into fine powder having a very good flowing property and yet an excellent binding force, and work as a suitable disintegrator in tablets.
Inventors
- 👤 Yoshiro Onda
- 👤 Hiroaki Muto
- 👤 Hiroshi Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:21
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2004; A61K9/2022; A61K9/205; A61K9/2054; C; C08; C08B; C08B11/00; C08B11/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
148 words
Method for preparing a cellulose ether with a molar substitution of from 0.05 to 1.0 ether groups which comprises etherifying an alkali cellulose in the presence of an etherificating agent to form a crude cellulose ether composition, neutralizing said composition in two stages: in a first stage neutralization dispersing and partly dissolving the crude cellulose ether to form a mixture in a first stage aqueous medium containing an acid in an amount equivalent to from about 5 to about 80% of the amount stoichiometrically required for the complete neutralization of all alkali groups in said mixture, in a second stage neutralization adding an additional amount sufficient to neutralize all the remaining alkali in said mixture to the said first stage aqueous medium, washing the resultant completely neutralized cellulose ether with water, drying the thus washed cellulose ether, and pulverizing the thus dried cellulose ether into finely divided powder.
Claim 2
Dependent Claim
148 words
Method for preparing a cellulose ether with a molar substitution of from 0.05 to 1.0 ether groups which comprises etherifying an alkali cellulose in the presence of an etherificating agent to form a crude cellulose ether composition, neutralizing said composition in two stages: in a first stage neutralization dispersing and partly dissolving the crude cellulose ether to form a mixture in a first stage aqueous medium containing an acid in an amount equivalent to from about 5 to about 80% of the amount stoichiometrically required for the complete neutralization of all alkali groups in said mixture, in a second stage neutralization adding an additional amount sufficient to neutralize all the remaining alkali in said mixture to the said first stage aqueous medium, washing the resultant completely neutralized cellulose ether with water, drying the thus washed cellulose ether, and pulverizing the thus dried cellulose ether into finely divided powder.
Claim 3
Dependent Claim
43 words
The method as claimed in claim 1, wherein the amount of the acid contained in the first stage aqueous medium is an amount equivalent to from about 7 to about 70% of the amount stoichiometrically required for the complete neutralization of all alkali.
Claim 4
Dependent Claim
27 words
The method as claimed in claim 1, wherein the etherificating agent is a member selected from the group consisting of an alkyl halide and an alkylene oxide.
Claim 5
Dependent Claim
14 words
The method as claimed in claim 1, wherein the cellulose ether produced is methylcellulose.
Claim 6
Dependent Claim
14 words
The method as claimed in claim 1, wherein the cellulose ether produced is hydroxyethylcellulose.
Claim 7
Dependent Claim
14 words
The method as claimed in claim 1, wherein the cellulose ether produced is hydroxypropylcellulose.
Claim 8
Dependent Claim
31 words
The method as claimed in claim 1, wherein the cellulose ether produced is a member selected from the group consisting of ethylcellulose, hydroxybutylcellulose, hydroxyethylmethylcellulose, hydroxyethylethylcellulose, hydroxypropylmethylcellulose, hydroxybutylethylcellulose, carboxymethylcellulose and salts thereof.
Claim 9
Dependent Claim
13 words
The method as claimed in claim 1, wherein the acid is acetic acid.
Claim 10
Dependent Claim
20 words
The method as claimed in claim 3, wherein the acid is acetic acid and the cellulose ether produced is methycellulose.
Claim 11
Dependent Claim
13 words
The method as claimed in claim 1, wherein the acid is hydrochloric acid.
Claim 12
Dependent Claim
18 words
The method as claimed in claim 1, wherein the dried cellulose ether is pulverized by a hammer mill.
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) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |