Patent US3726835A successfully refreshed from Google Patents.
US3726835A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyurethane prepolymers cured with melamine or dicyandiamide
Assignee: ATK Launch Systems LLC
•
Filing: 1971-01-12
•
Granted: 1973-04-10
•
Expires: 1991-01-12
Abstract
Abstract A STORAGE-STABLE POLYURETHANE PREPOLYMER HAS BEEN PREPARED IN WHICH THE STABILIZER IS MELAMINE OR DICYANDIAMIDE ADMIXED THERTO, UPON HEATING OF THE MELAMINE ADMIXED PREPOLYMER, THE COMPOSITION IS CURED TO A VERY TOUGH POLYMER IN A SHORT TIME HAVING A HARDNESS OF 70 DUROMETER A VALUE FORMING A VARIETY OF CAST SHAPES.
Inventors
- 👤 E Bertozzi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:56
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/67; C08G18/69; C08G18/08; C08G18/10; C08G18/40; C08G18/64; C08G18/6453
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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 |