US3049537A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water-soluble cellulose ethers and process
Assignee: Hercules Powder Co
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Filing: 1960-03-21
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Granted: 1962-08-14
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Expires: 1980-03-21
Abstract
No abstract record available.
Inventors
- 👤 Eugene D Klug
- 👤 William D Roberson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:35
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/08; C08B11/20; C08B11/22
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
175 words
IN THE PROCESS OF PREPARING WATER-SOLUBLE HYDROXYALKYL CELLULOSE ETHERS WHEREIN CELLULOSIC MATERIAL IS CONTACTED WITH A BASE, THE CELLULOSIC MATERIAL IS ETHERIFIED AND THE CELLULOSE ETHER IS PURFIED BY NEUTRALIZING THE BASE AND REMOVING THE SALTS FORMED AND OTHER IMPURITIES WITH A SOLVENT THEREFOR, THE IMPROVEMENT IN THE PURIFICATION WHICH COMPRISES NEUTRALIZING THE BASE WITH CERTAIN ACIDS FOLLOWED BY REMOVING THE IMPURITIES FROM THE ETHER WITH CERTAIN SOLVENTS, THE COMBINATION OF ACIDS AND SOLVENTS BEINGS SELECTED FROM THE GROUP CONSISTING OF (1) PROPIONIC ACID IN COMBINATION WITH A SOLVENT SELECTED FROM THE GROUP CONSISTING OF ISOPROPYL ACOHOL, TERTIARY BUTYL ALCOHOL, AND SECONDARY BUTYL ALCOHOL, AND (2) BENZOIC ACID, NITRIC ACID, AND ACETIC ACID-NITRIC ACID MIXTURE IN COMBINATION WITH A SOLVENT SELECTED FROM THE GROUP CONSISTING OF ISOPROPYL ALCOHOL, TERTIARY BUTYL ALCOHOL, SECONDARY BUTYL ALCOHOL, ACETONE, AND DIOXANE, EACH OF SAID SOLVENTS IN (1) AND (2) ABOVE BEONG EMPLOYED AS 70%-90% AQUEOUS SOLUTIONS THEREOF, THE PROPORTIONS OF ACIDS IN SAID ACETIC ACID-NITRIC ACID MIXTURE BEING ABOUT 98%-80% NITRIC AND ABOUT 2%-20% ACETIC BY WEIGHT THEREOF, RESPECTIVELY.
Claim 2
Dependent Claim
175 words
IN THE PROCESS OF PREPARING WATER-SOLUBLE HYDROXYALKYL CELLULOSE ETHERS WHEREIN CELLULOSIC MATERIAL IS CONTACTED WITH A BASE, THE CELLULOSIC MATERIAL IS ETHERIFIED AND THE CELLULOSE ETHER IS PURFIED BY NEUTRALIZING THE BASE AND REMOVING THE SALTS FORMED AND OTHER IMPURITIES WITH A SOLVENT THEREFOR, THE IMPROVEMENT IN THE PURIFICATION WHICH COMPRISES NEUTRALIZING THE BASE WITH CERTAIN ACIDS FOLLOWED BY REMOVING THE IMPURITIES FROM THE ETHER WITH CERTAIN SOLVENTS, THE COMBINATION OF ACIDS AND SOLVENTS BEINGS SELECTED FROM THE GROUP CONSISTING OF (1) PROPIONIC ACID IN COMBINATION WITH A SOLVENT SELECTED FROM THE GROUP CONSISTING OF ISOPROPYL ACOHOL, TERTIARY BUTYL ALCOHOL, AND SECONDARY BUTYL ALCOHOL, AND (2) BENZOIC ACID, NITRIC ACID, AND ACETIC ACID-NITRIC ACID MIXTURE IN COMBINATION WITH A SOLVENT SELECTED FROM THE GROUP CONSISTING OF ISOPROPYL ALCOHOL, TERTIARY BUTYL ALCOHOL, SECONDARY BUTYL ALCOHOL, ACETONE, AND DIOXANE, EACH OF SAID SOLVENTS IN (1) AND (2) ABOVE BEONG EMPLOYED AS 70%-90% AQUEOUS SOLUTIONS THEREOF, THE PROPORTIONS OF ACIDS IN SAID ACETIC ACID-NITRIC ACID MIXTURE BEING ABOUT 98%-80% NITRIC AND ABOUT 2%-20% ACETIC BY WEIGHT THEREOF, RESPECTIVELY.
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) | 1965-08-13 | 1966-02-12 | 1966-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-08-13 | 1970-02-12 | 1970-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-08-13 | 1974-02-12 | 1974-08-14 | $7700.00 | Window Closed / Lapsed |