US4035195A
Expired / Lapsed
US
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Crosslinking cellulose polymers
Assignee: Hercules LLC
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Filing: 1975-08-11
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Granted: 1977-07-12
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Expires: 1995-08-11
Abstract
Abstract Thickened aqueous solutions are prepared by crosslinking carboxymethyl hydroxyethyl cellulose solutions in brine via polyvalent metal ions. The CMHEC employed is characterized by specified carboxymethyl and hydroxyethyl substitution levels.
Inventors
- 👤 Thomas J. Podlas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:29
CPC Classifications
C; C08; C08B; C08B15/00; C08B15/005; C08L; C08L1/00; C08L1/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
112 words
A method of perparing a thickened aqueous brine solution which comprises providing an aqueous solution of at least about 0.025% by weight of carboxymethyl hydroxyethyl cellulose and crosslinking said carboxymethyl hydroxyethyl cellulose in solution with a polyvalent metal cation, said carboxymethyl hydroxyethyl cellulose being one wherein the carboxymethyl D.S. is between about 0.2 and 0.6 and the hydroxyethyl M.S. is between about 1.5 and 3.0, and said polyvalent metal cation being provided in the form of a salt wherein said metal cation is present in the same cationic valence state as the crosslinking species, and the mole ratio of said polyvalent metal cation to carboxyl groups being between about 0.02 and 1.
Claim 2
Independent Claim
112 words
A method of perparing a thickened aqueous brine solution which comprises providing an aqueous solution of at least about 0.025% by weight of carboxymethyl hydroxyethyl cellulose and crosslinking said carboxymethyl hydroxyethyl cellulose in solution with a polyvalent metal cation, said carboxymethyl hydroxyethyl cellulose being one wherein the carboxymethyl D.S. is between about 0.2 and 0.6 and the hydroxyethyl M.S. is between about 1.5 and 3.0, and said polyvalent metal cation being provided in the form of a salt wherein said metal cation is present in the same cationic valence state as the crosslinking species, and the mole ratio of said polyvalent metal cation to carboxyl groups being between about 0.02 and 1.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the carboxymethyl hydroxyethyl cellulose concentration is between 0.025 and 1%.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein the carboxymethyl hydroxyethyl cellulose concentration is between about 0.025 and 0.4%.
Claim 5
Dependent Claim
16 words
The method according to claim 3 wherein the polyvalent metal ion is trivalent chromium or aluminum.
Claim 6
Dependent Claim
20 words
The method of claim 4 wherein the mole ratio of metal ions to carboxyl groups is about 0.05 to 1.
Claim 7
Dependent Claim
32 words
The method of claim 4 wherein the polyvalent metal ion is trivalent chromium derived from a chromium salt selected from the class consisting of chromium perchlorate, chromium nitrate and chromium potassium sulfate.
References Cited (Backward Citations)
US3804174A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |