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US4200736A
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Preparation of water-insoluble carboxymethyl cellulose absorbents
Assignee: JPMorgan Chase Bank NA
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Filing: 1978-05-17
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Granted: 1980-04-29
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Expires: 1998-05-17
Abstract
Abstract A process for the preparation of a substantially water-insoluble, particulate sodium salt of carboxymethyl cellulose, suitable for use as an absorbent in tampons and other catamenial devices or the like. The process involves heating solid, water-soluble sodium carboxymethyl cellulose, having a degree of substitution of at least 0.4, with carbon dioxide gas to substantially insolubilize the carboxymethyl cellulose and convert it to a form suitable for absorbent applications.
Inventors
- 👤 Makoto Shinohara
- 👤 Nathan D. Field
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:29
CPC Classifications
C; C08; C08B; C08B15/00; C08B15/005; A; A61; A61L; A61L15/00; A61L15/16; A61L15/22; A61L15/28
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
66 words
A process for the preparation of substantially water-insoluble, particulate carboxymethyl cellulose, which comprises heating a solid, water-soluble, particulate sodium carboxymethyl cellulose having a degree of substitution of at least 0.4 at temperatures in excess of 100° C. and in the presence of carbon dioxide gas, to thereby substantially insolubilize the carboxymethyl cellulose, the thus insolubilized carboxymethyl cellulose exhibiting a swell ratio of from 5 to 50.
Claim 2
Dependent Claim
66 words
A process for the preparation of substantially water-insoluble, particulate carboxymethyl cellulose, which comprises heating a solid, water-soluble, particulate sodium carboxymethyl cellulose having a degree of substitution of at least 0.4 at temperatures in excess of 100° C. and in the presence of carbon dioxide gas, to thereby substantially insolubilize the carboxymethyl cellulose, the thus insolubilized carboxymethyl cellulose exhibiting a swell ratio of from 5 to 50.
Claim 3
Dependent Claim
19 words
The process of claim 1, wherein the insolubilized sodium carboxymethyl cellulose has an extractables content of less than 40%.
Claim 4
Dependent Claim
22 words
The process of claim 1, wherein the solid, water-soluble sodium carboxymethyl cellulose has a degree of substitution of from 0.5 to 1.2.
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein the sodium carboxymethyl cellulose is heated at temperatures of from 120° to 190° C.
Claim 6
Dependent Claim
17 words
The process of claim 1, wherein the ambient atmosphere comprises at least 20% by volume carbon dioxide.
Claim 7
Dependent Claim
20 words
The process of claim 1, wherein the carbon dioxide gas is passed over or through the particulate sodium carboxymethyl cellulose.
Claim 8
Dependent Claim
22 words
The process of claim 1, wherein the particulate sodium carboxymethyl cellulose is contacted by a stagnant charge of the carbon dioxide gas.
Claim 9
Dependent Claim
61 words
The process of claim 1, wherein the soluble sodium carboxymethyl cellulose reacted has a degree of substitution of from 0.5 to 1.2, wherein the carboxymethyl cellulose is heated at temperatures of from 125° to 180° C., and wherein the insoluble sodium carboxymethyl cellulose produced exhibits a swell ratio of from 5 to 40 and an extractables content of less than 35%.
References Cited (Backward Citations)
US2447757A
Cited
US2639239A
Cited
US2766137A
Cited
US3322748A
Cited
US3379721A
Cited
US3731686A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-29 | 1983-10-29 | 1984-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-29 | 1987-10-29 | 1988-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-29 | 1991-10-29 | 1992-04-29 | $7700.00 | Window Closed / Lapsed |