Patent US6379334B1 successfully refreshed from Google Patents.
US3131176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of water-soluble hydroxyalkyl cellulose ethers
Assignee: Hercules Powder Co
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Filing: 1960-04-13
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Granted: 1964-04-28
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Expires: 1980-04-13
Abstract
No abstract record available.
Inventors
- 👤 Eugene D Klug
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 17:08
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
101 words
PROCESS OF PREPARING WATER-SOLUBLE HYDROXYALKYL CELLULOSE ETHERS COMPRISING (1) A FIRST STAGE WHEREIN CELLULOSE IS HYDROXYALKYLATED IN THE PRESENCE OF AN ALKALI AND WATER TO AN MS NOT EXCEEDING 0.8, AND ALKALI AND OTHER IMPURITIES ARE REMOVED, THE AMOUNT OF ALKALI REMOVED BEING AT LEAST ENOUGH TO LEAVE ONLY THAT AMOUNT SPECIFIED FOR THE SECOND STAGE, THE ALKALI/CELLULOSE AND WATER/CELLULOSE RATIOS BEING 0.2/1-0.8/1 AND 0.8/1-4.0/1, RESPECTIVELY, (2) A SECOND STAGE WHEREIN HYDROXYALKYLATION OF THE RESULTING PARTIALLY HYDROXYALKYLATED AND PURIFIED CELLUSOSE IS CONTINUED IN THE PRESENCE OF ALKALI USING AN ALKALI/HYDROXYALKYL CELLULOSE RATIO OF 0.005/1-0.1/1 AND A WATER/HYDROXYALKYL CELLULOSE RATIO OF 1/1-20/1.
Claim 2
Dependent Claim
101 words
PROCESS OF PREPARING WATER-SOLUBLE HYDROXYALKYL CELLULOSE ETHERS COMPRISING (1) A FIRST STAGE WHEREIN CELLULOSE IS HYDROXYALKYLATED IN THE PRESENCE OF AN ALKALI AND WATER TO AN MS NOT EXCEEDING 0.8, AND ALKALI AND OTHER IMPURITIES ARE REMOVED, THE AMOUNT OF ALKALI REMOVED BEING AT LEAST ENOUGH TO LEAVE ONLY THAT AMOUNT SPECIFIED FOR THE SECOND STAGE, THE ALKALI/CELLULOSE AND WATER/CELLULOSE RATIOS BEING 0.2/1-0.8/1 AND 0.8/1-4.0/1, RESPECTIVELY, (2) A SECOND STAGE WHEREIN HYDROXYALKYLATION OF THE RESULTING PARTIALLY HYDROXYALKYLATED AND PURIFIED CELLUSOSE IS CONTINUED IN THE PRESENCE OF ALKALI USING AN ALKALI/HYDROXYALKYL CELLULOSE RATIO OF 0.005/1-0.1/1 AND A WATER/HYDROXYALKYL CELLULOSE RATIO OF 1/1-20/1.
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) | 1967-04-28 | 1967-10-28 | 1968-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-04-28 | 1971-10-28 | 1972-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-04-28 | 1975-10-28 | 1976-04-28 | $7700.00 | Window Closed / Lapsed |