US4404371A
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Carboxymethylcellulose with carbonate bridges and preparation thereof
Assignee: Battelle Memorial Institute Inc
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Filing: 1981-12-28
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Granted: 1983-09-13
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Expires: 2001-12-28
Abstract
Abstract Cross-linked carboxymethylcellulose with intermolecular carbonate bridges.
Inventors
- 👤 Gunter Bellmann
- 👤 Celeste Cervini
- 👤 Jean-Pierre Sachetto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:29
CPC Classifications
C; C08; C08B; C08B15/00; C08B15/005
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
23 words
Cross-linked carboxymethylcellulose (CMC) having cross-linking intermolecular bridges consisting mainly of carbonate bridges involving the primary or secondary hydroxy functions of the CMC chains.
Claim 2
Dependent Claim
23 words
Cross-linked carboxymethylcellulose (CMC) having cross-linking intermolecular bridges consisting mainly of carbonate bridges involving the primary or secondary hydroxy functions of the CMC chains.
Claim 3
Dependent Claim
29 words
Cross-linked CMC according to claim 1, which provides, with water, a gel or a solution of viscosity of the order of 10,000 to 20,000 cP at 0.5% by weight.
Claim 4
Dependent Claim
22 words
Cross-linked CMC according to claim 1, in which a proportion of the COOH groups is esterified with an alcohol or a phenol.
Claim 5
Dependent Claim
31 words
Cross-linked CMC according to claim 2, the absorptive capacity per gram of which amounts, after drying, to 20 to 150 ml H 2 O or to 10-75 ml 1% aqueous NaCl.
Claim 6
Dependent Claim
32 words
Cross-linked CMC according to claim 4, the absorption rate of which toward 1% aqueous NaCl is of the order of 1 to 5 ml/g.min under a pressure of 10 g/cm 2 .
Claim 7
Dependent Claim
18 words
Cross-linked CMC according to claim 1, having a degree of susbtitution of COOH (DS) between 0.2 and 2.
Claim 8
Dependent Claim
72 words
A method for the preparation of the cross-linked CMC according to claim 1, comprising treating, in a homogeneous phase at room temperature, a CMC of DS from 0.2 to 2 said CMC being entirely dissolved in water or in a water-alcohol or water-acetone medium with a pH near neutrality, with 0.02 to 1 equivalent of alkyl chloroformate per equivalent of gluco-pyranose unit in the presence, as a catalyst, of a tertiary amine.
Claim 9
Dependent Claim
41 words
The method of claim 7, further comprising the steps of precipitating said cross-linked CMC with a hydro-compatible solvent from the reaction mixture, separating the precipitate, purifying said precipitate by redissolving in water and reprecipitating said cross-linked CMC with a hydro-compatible solvent.
Claim 10
Dependent Claim
14 words
The method of claim 7, wherein the tertiary amine used is pyridine or N-methylmorpholine.
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) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |