US4697008A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of water-insoluble alkali metal salts of carboxyalkyl cellulose
Assignee: DKS Co Ltd
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Filing: 1986-12-11
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Granted: 1987-09-29
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Expires: 2006-12-11
Abstract
Abstract A method of producing a water-insoluble alkali metal salt of carboxyalkyl cellulose such as CMC is disclosed. The method comprises reacting a water-soluble alkali metal salt of carboxyalkyl cellulose with an aliphatic hydroxycarboxylic acid.
Inventors
- 👤 Hideharu Asano
- 👤 Hisakazu Senda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:37
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/20; C08B11/02; C08B11/04; C08B11/10; C08B11/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
28 words
A method of producing a water-insoluble alkali metal salt of carboxyalkyl cellulose which comprises reacting a water-soluble alkali metal salt of carboxyalkyl cellulose with an aliphatic hydroxycarboxylic acid.
Claim 2
Independent Claim
28 words
A method of producing a water-insoluble alkali metal salt of carboxyalkyl cellulose which comprises reacting a water-soluble alkali metal salt of carboxyalkyl cellulose with an aliphatic hydroxycarboxylic acid.
Claim 3
Dependent Claim
24 words
The method according to claim 1, wherein said water-soluble alkali metal salt of carboxyalkyl cellulose has a degree of substitution from 0.4 to 1.0.
Claim 4
Dependent Claim
20 words
The method according to claim 1, wherein said alkali metal salt of carboxyalkyl cellulose is sodium salt of carboxymethyl cellulose.
Claim 5
Dependent Claim
26 words
The method according to claim 1, wherein said hydroxycarboxylic acid is glycolic acid, lactic acid, malic acid, tartronic acid, methyltartronic acid, citric acid or tartaric acid.
Claim 6
Dependent Claim
27 words
The method according to claim 2, wherein said hydroxycarboxylic acid amounts from 0.4 to 1.8 times in equivalent as free acid relative to said degree of substitution.
Claim 7
Independent Claim
76 words
A method of producing a water-insoluble alkali metal salt of carboxyalkyl cellulose which comprises the steps of: reacting a cellulosic material with a carboxyalkylating agent and an alkali metal hydroxide in a water-containing organic solvent; adding an aliphatic hydroxycarboxylic acid to the resulting reaction mixture and heating the mixture at a temperature of 65° to 95° C. for 30 to 90 minutes; and recovering the water-insoluble alkali metal salt of carboxyalkyl cellulose from the reaction mixture.
Claim 8
Independent Claim
76 words
A method of producing a water-insoluble alkali metal salt of carboxyalkyl cellulose which comprises the steps of: reacting a cellulosic material with a carboxyalkylating agent and an alkali metal hydroxide in a water-containing organic solvent; adding an aliphatic hydroxycarboxylic acid to the resulting reaction mixture and heating the mixture at a temperature of 65° to 95° C. for 30 to 90 minutes; and recovering the water-insoluble alkali metal salt of carboxyalkyl cellulose from the reaction mixture.
Claim 9
Dependent Claim
21 words
The method according to claim 6, wherein said carboxyalkylating agent is monochloroacetic acid and said alkali metal hydroxide is sodium hydroxide.
Claim 10
Dependent Claim
12 words
The method according to claim 6, wherein said organic solvent is isopropanol.
Claim 11
Dependent Claim
23 words
The method according to claim 6, wherein said alkali metal salt of carboxyalkyl cellulose has a degree of substitution from 0.4 to 1.0.
Claim 12
Dependent Claim
26 words
The method according to claim 6, wherein said hydroxycarboxylic acid is glycolic acid, lactic acid, malic acid, tartronic acid, methyltartronic acid, citric acid or tartaric acid.
Claim 13
Dependent Claim
27 words
The method according to claim 9, wherein said hydroxycarboxylic acid amounts from 0.4 to 1.8 times in equivalent as free acid relative to said degree of substitution.
References Cited (Backward Citations)
US3375245A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-09-28 | 1991-03-30 | 1991-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-28 | 1995-03-30 | 1995-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-28 | 1999-03-30 | 1999-09-29 | $7700.00 | Window Closed / Lapsed |