Patent US2963395A successfully refreshed from Google Patents.
US2963395A
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Process of bleaching lignocellulosic pulps
Assignee: Fort James Corp
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Filing: 1958-03-31
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Granted: 1960-12-06
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Expires: 1978-03-31
Abstract
No abstract record available.
Inventors
- 👤 Back Sangho
- 👤 Delmer D Hinrichs
- 👤 James D Wethern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:24
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1005; D21C9/1084; D21C9/1089
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
130 words
THE CONTINUOUS PROCESS OF BLEACHING LIGNOCELLULOSIC PULP WHICH COMPRISES FEEDING INTO AN AIR-TIGHT ZONE A SEMI-SOLID, NON-FLOWABLE, MOIST MASS OF PULP IN PATRICULATE FORM, REMOVING SUBSTANTIALLY ALL OF THE AIR THEREFROM, FORMING A MIXTURE CONTAINING SAID PULP AND A REDUCING BLEACHING AGENT COMPRISING ESSENTIALLY A STABILIZED AQUEOUS SOLUTION OF A HYDROSULFITE SELECTED FROM THE GROUP CONSISTING OF ZINC, ALKALI METAL AND AMMONIUM HYDROSULFITES, THE AMOUNT OF SAID HYDROSULFITE BEING FROM 0.2% TO 5%, BY WEIGHT, OVEN-DRY PULP BASIS, AND MIXING MECHANICALLY SAID PULP WITH SAID HYDROSULFITE IN AN ATMOSPHERE SUBSTANTIALLY FREE OF OXYGEN AT A TEMPERATURE OF FROM 100*F. TO 230*F. FOR A PERIOD OF TIME SUFFICIENT TO PRODUCE A SUBSTANTIALLY INCREASE IN THE PULP BRIGHTNESS, THE PH OF SAID MIXTURE DURING BLEACHING BEING MAINTAINED BETWEEN ABOUT 4 AND 8.
Claim 2
Dependent Claim
130 words
THE CONTINUOUS PROCESS OF BLEACHING LIGNOCELLULOSIC PULP WHICH COMPRISES FEEDING INTO AN AIR-TIGHT ZONE A SEMI-SOLID, NON-FLOWABLE, MOIST MASS OF PULP IN PATRICULATE FORM, REMOVING SUBSTANTIALLY ALL OF THE AIR THEREFROM, FORMING A MIXTURE CONTAINING SAID PULP AND A REDUCING BLEACHING AGENT COMPRISING ESSENTIALLY A STABILIZED AQUEOUS SOLUTION OF A HYDROSULFITE SELECTED FROM THE GROUP CONSISTING OF ZINC, ALKALI METAL AND AMMONIUM HYDROSULFITES, THE AMOUNT OF SAID HYDROSULFITE BEING FROM 0.2% TO 5%, BY WEIGHT, OVEN-DRY PULP BASIS, AND MIXING MECHANICALLY SAID PULP WITH SAID HYDROSULFITE IN AN ATMOSPHERE SUBSTANTIALLY FREE OF OXYGEN AT A TEMPERATURE OF FROM 100*F. TO 230*F. FOR A PERIOD OF TIME SUFFICIENT TO PRODUCE A SUBSTANTIALLY INCREASE IN THE PULP BRIGHTNESS, THE PH OF SAID MIXTURE DURING BLEACHING BEING MAINTAINED BETWEEN ABOUT 4 AND 8.
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) | 1963-12-06 | 1964-06-06 | 1964-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-12-06 | 1968-06-06 | 1968-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-12-06 | 1972-06-06 | 1972-12-06 | $7700.00 | Window Closed / Lapsed |