Patent US3726836A successfully refreshed from Google Patents.
US3726836A
Expired / Lapsed
US
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Viscosity-stabilized solution of polyurethane
Assignee: Asahi Kasei Corp
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Filing: 1971-03-25
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Granted: 1973-04-10
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Expires: 1991-03-25
Abstract
Abstract METHOD OF MANUFACTURING A STABILIZED SOLUTION OF POLYURETHANE FROM A PREPOLYMER HAVING TERMINAL ISOCYANATE GROUPS. THE STABILIZED SOLUTION IS OBTAINED BY THE USE OF A BIFUNCTIONAL CHAIN EXTENDER IN COMBINATION WITH A N,NDIALKYLHYDRAZINE AND/OR A N,N-DIARYLHYDRAZINE AND THE SUBSEQUENT AGING UNDER HEATING. THE VISCOSITY OF THE STABILIZING SOLUTION IS REPRODUCIBLE, AND DOES NOT UNDERGO ANY CHANGE ON HEATING AND/OR ON THE LAPSE OF TIME. THE POLYURETHANE OBTAINED ACCORDING TO THIS INVENTION HAS ALSO A LIGHT RESISTANCE AND THEREFORE, THE MOLDED ARTICLE PRODUCED THEREFROM HAS A SUPERIOR RETENTION OF STRENGTH. THE SOLUTION IS USEFUL FOR MAKING FIBERS, FILMS, MOLDED ARTICLES, ETC.
Inventors
- 👤 Y Nakahara
- 👤 J Ohmura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:28
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |