US3250748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of water-soluble polyvinyl alcohol-urea derivatives
Assignee: Kurashiki Rayon Co Ltd
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Filing: 1961-12-01
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Granted: 1966-05-10
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Expires: 1981-12-01
Abstract
No abstract record available.
Inventors
- 👤 Suzumura Hideo
- 👤 Hirano Katsuaki
- 👤 Chiba Teiichiro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:06
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/16; C08K5/21; C08F; C08F8/00; C08F8/30
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
166 words
AN IMPROVED PROCESS FOR THE PREPARATION OF A WATER SOLUBLE DERIVATIVE OF POLYVINYL ALCOHOL HAVING A CONTENT OF COMBINED NITROGEN HIGHER THAN 0.4 PERCENT WHICH CONSISTS ESSENTIALLY OF PREPARING A UNIFORM POLYVINYL ALCOHOLUREA POWDER BY MIXING POLYVINYL ALCOHOL POWDER WITH UREA IN SOLUTION IN A SOLVENT SELECTED FROM THE GROUP CONSISTING OF WATER AND ORGANIC SOLVENTS FOR UREA AND DRYING THE RESULTING MIXTURE TO REMOVE SAID SOLVENT, INTRODUCING SAID UNIFORM POLYVINYL ALCOHOL-UREA POWDER INTO AN EXTRUSION REACTION ZONE MAINTAINED AT A TEMPERATURE HIGHER THAN ABOUT 140*C., PASSING SAID UNIFORM POLYVINYL ALCOHOL-UREA POWDER THROUGH SAID ZONE WHILE MAINTAINING SAID ZONE TEMPERATURE HIGHER THAN ABOUT 140*C., WHEREBY SAID INTRODUCED MIXTURE IS HEATED AND SAID POLYVINYL ALCOHOL AND SAID UREA REACT TO PRODUCE A UNIFORM REACTION PRODUCT, THE REACTION TIME IN SAID ZONE BEING SUFFICIENT TO PRODUCE SAID PRODUCT, AND RECOVERING THE REACTION PRODUCT MIXTURE WHICH HAS BEEN EXTRUDED FROM SAID ZONE CONTAINING A WATER-SOLUBLE DERIVATIVE OF POLYVINYL ALCOHOL HAVING A CONTENT OF COMBINED NITROGEN HIGHER THAN 0.4 PERCENT.
Claim 2
Dependent Claim
166 words
AN IMPROVED PROCESS FOR THE PREPARATION OF A WATER SOLUBLE DERIVATIVE OF POLYVINYL ALCOHOL HAVING A CONTENT OF COMBINED NITROGEN HIGHER THAN 0.4 PERCENT WHICH CONSISTS ESSENTIALLY OF PREPARING A UNIFORM POLYVINYL ALCOHOLUREA POWDER BY MIXING POLYVINYL ALCOHOL POWDER WITH UREA IN SOLUTION IN A SOLVENT SELECTED FROM THE GROUP CONSISTING OF WATER AND ORGANIC SOLVENTS FOR UREA AND DRYING THE RESULTING MIXTURE TO REMOVE SAID SOLVENT, INTRODUCING SAID UNIFORM POLYVINYL ALCOHOL-UREA POWDER INTO AN EXTRUSION REACTION ZONE MAINTAINED AT A TEMPERATURE HIGHER THAN ABOUT 140*C., PASSING SAID UNIFORM POLYVINYL ALCOHOL-UREA POWDER THROUGH SAID ZONE WHILE MAINTAINING SAID ZONE TEMPERATURE HIGHER THAN ABOUT 140*C., WHEREBY SAID INTRODUCED MIXTURE IS HEATED AND SAID POLYVINYL ALCOHOL AND SAID UREA REACT TO PRODUCE A UNIFORM REACTION PRODUCT, THE REACTION TIME IN SAID ZONE BEING SUFFICIENT TO PRODUCE SAID PRODUCT, AND RECOVERING THE REACTION PRODUCT MIXTURE WHICH HAS BEEN EXTRUDED FROM SAID ZONE CONTAINING A WATER-SOLUBLE DERIVATIVE OF POLYVINYL ALCOHOL HAVING A CONTENT OF COMBINED NITROGEN HIGHER THAN 0.4 PERCENT.
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) | 1969-05-09 | 1969-11-08 | 1970-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-05-09 | 1973-11-08 | 1974-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-05-09 | 1977-11-08 | 1978-05-10 | $7700.00 | Window Closed / Lapsed |