Continuous esterification of cellulose
Abstract
Abstract CONTINUOUSLY ESTERFIED CELLULOSE FLAKE HAVING A LOW STANDARD DERIVATION IN VISCOISTY, A LOW STANDARD DERIVATION IN ACETYL VALUE AND A LOW PERCENTAGE OF COMBINED SULFATES ARE PRODUCED BY A CONTINUOUS PROCESS COMPRISING THE FOLLOWING STEPS: (1) SLURRYING CELLULOSE IN A LOWER FATTY ACID/WATER SLURRY; (2) WASHING SAID SLURRY WITH LOWER FATTY ACID AND EXTRACTING WATER FROM THE CELLULOSE SLURRY; (3) ADDING AN EFFECTIVE AMOUNT OF AN ACID CATALYST; (4) MIXING THE PRETREATED CELLULOSE CONTAINING THE LOWER FATTY ACID AND CATALYST WITH A LOWER FATTY ACID/ LOWER FATTY ACID ANHYDRIDE MIXTURE CONTAINING EXCESS ANHYDRIDE AND ESTERIFYING THE CELLULOSE MIXTURE; (5) BLENDING THE ESTERIFIED DOPE WITH AN AQUEOUS SOLUTION OF NEUTRALIZING SALT; (6) DESULFATING THE PARTIALLY NEUTRALILZED ACETYLATED DOPE; AND (7) ADDING AN AQUEOUS NEUTRALIZING SAL T TO THE DESULFATED DOPE TO STOP ALL REACTIONS.
Inventors
- 👤 Charles G Horne Jr
- 👤 Carl J Howell Jr
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |