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US4183765A
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Method of increasing viscosity of hydroxyalkyl cellulose solutions
Assignee: Hercules LLC
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Filing: 1978-07-14
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Granted: 1980-01-15
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Expires: 1998-07-14
Abstract
Abstract Viscosity of hydroxyalkyl cellulose solutions is increased by treatment with benzoquinone under controlled conditions of pH.
Inventors
- 👤 Thomas J. Podlas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:56
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/04; C08K5/07; C08K5/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
79 words
A method of increasing the viscosity of an aqueous solution of a hydroxyalkyl ether of cellulose which comprises contacting a solution containing at least about 0.075% by weight of said ether with about 0.4 to 75% by weight, based on the ether, of benzoquinone, said solution having a pH greater than 6.4 after addition of the benzoquinone and having sufficient buffering capacity to retain a pH greater than 6.4 for at least 24 hours following addition of benzoquinone thereto.
Claim 2
Independent Claim
79 words
A method of increasing the viscosity of an aqueous solution of a hydroxyalkyl ether of cellulose which comprises contacting a solution containing at least about 0.075% by weight of said ether with about 0.4 to 75% by weight, based on the ether, of benzoquinone, said solution having a pH greater than 6.4 after addition of the benzoquinone and having sufficient buffering capacity to retain a pH greater than 6.4 for at least 24 hours following addition of benzoquinone thereto.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein the hydroxyalkyl ether of cellulose is hydroxyethyl cellulose.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein the hydroxyalkyl ether of cellulose is hydroxypropyl cellulose.
Claim 5
Dependent Claim
25 words
A dry blend of a hydroxyalkyl ether of cellulose and about 0.4 to 75% by weight, based on the weight of said ether, of benzoquinone.
Claim 6
Dependent Claim
25 words
A dry blend of a hydroxyalkyl ether of cellulose and about 0.4 to 75% by weight, based on the weight of said ether, of benzoquinone.
References Cited (Backward Citations)
US2555265A
Cited
US3953336A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-14 | 1983-07-16 | 1984-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-14 | 1987-07-16 | 1988-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-14 | 1991-07-16 | 1992-01-15 | $7700.00 | Window Closed / Lapsed |