US3385845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and device for the xanthation of alkali cellulose
Assignee: Valmet AB
•
Filing: 1963-04-05
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Granted: 1968-05-28
•
Expires: 1983-04-05
Abstract
No abstract record available.
Inventors
- 👤 Treiber Erich Emmerich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:48
CPC Classifications
B; B01; B01J; B01J19/00; B01J19/18; B01J19/1862; D; D01; D01F; D01F2/00; D01F2/06; D01F2/08; B01J2219/00; B01J2219/00049; B01J2219/00051; B01J2219/0015; B01J2219/00155; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49069
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
121 words
A PROCESS FOR XANTHOGENATING ALKALI CELLULOSE CONTINUOUSLY STEP BY STEP IN THE MANUFACTURE OF VISCOSE, WHICH COMPRISES INTRODUCING ALKALI CELLULOSE INTO A COMPARTMENT; REMOVING AIR BY EVACUATION FROM THE ALKALI CELLULOSE PRESENT IN NON-COMPRESSED DRY CONDITION IN SAID COMPARTMENT IN A FIRST STEP; INTRODUCING THE ALKALI CELLULOSE STILL IN NON-COMPRESSED DRY CONDITION TOGETHER WITH CARBON BISULPHIDE INTO A SECOND COMPARTMENT IN A SECOND STEP WHILE MAINTAINING SUCH CONDITIONS OF PRESSURE, TIME AND TEMPERATURE THAT THE XANTHATION IS CARRIED OUT IN THE GASEOUS PHASE TO A SUBSTANTIAL DEGREE BUT NOT COMPLETELY; DISCHARGING THE RESULTING REACTION MASS STILL IN NON-COMPRESSED CONDITION TO A FOLLOWING VESSEL; AND COMPLETING THE REACTION IN A THRID STEP BY WET XANTHATION IN THE PRESENCE OF CAUSTIC SODA LYE.
Claim 2
Dependent Claim
121 words
A PROCESS FOR XANTHOGENATING ALKALI CELLULOSE CONTINUOUSLY STEP BY STEP IN THE MANUFACTURE OF VISCOSE, WHICH COMPRISES INTRODUCING ALKALI CELLULOSE INTO A COMPARTMENT; REMOVING AIR BY EVACUATION FROM THE ALKALI CELLULOSE PRESENT IN NON-COMPRESSED DRY CONDITION IN SAID COMPARTMENT IN A FIRST STEP; INTRODUCING THE ALKALI CELLULOSE STILL IN NON-COMPRESSED DRY CONDITION TOGETHER WITH CARBON BISULPHIDE INTO A SECOND COMPARTMENT IN A SECOND STEP WHILE MAINTAINING SUCH CONDITIONS OF PRESSURE, TIME AND TEMPERATURE THAT THE XANTHATION IS CARRIED OUT IN THE GASEOUS PHASE TO A SUBSTANTIAL DEGREE BUT NOT COMPLETELY; DISCHARGING THE RESULTING REACTION MASS STILL IN NON-COMPRESSED CONDITION TO A FOLLOWING VESSEL; AND COMPLETING THE REACTION IN A THRID STEP BY WET XANTHATION IN THE PRESENCE OF CAUSTIC SODA LYE.
References Cited (Backward Citations)
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Cited
GB488761A
Cited
US2508987A
Cited
US2542492A
Cited
US2648661A
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US2985647A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-05-28 | 1971-11-27 | 1972-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-05-28 | 1975-11-27 | 1976-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-05-28 | 1979-11-27 | 1980-05-28 | $7700.00 | Window Closed / Lapsed |