Process for the manufacture of polyurethane spinning and coating solutions
Abstract
Abstract A PROCESS FOR THE MANUFACTURE OF A SOLUTION OF A POLYURETHANE CONTAINING ISOCYANATE-REACTIVE GROUPS WHICH COMPRISES REACTING TOGETHER IN AN INERT SOLVENT AN ESSENTIALLY LINEAR HYDROXYL-ENDED POLYMER, AN AT LEAST TRIFUNCTIONAL POLYOL AND AN EXCESS OF AN ORGANIC DIISOCYANATE TO FORM AN ISOCYANATE-ENDED PREPOLYMER, THEN ADDING A DIHYDRIC ALCOHOL OR A MIXTURE THEREOF WITH WATER AND ALLOWING REACTION TO PROCEED UNTIL THE SOLUTION HAS ATTAINED A VISCOSITY WITHIN A PREDETERMINED RANGE, AND FINALLY ADDING A POLYFUNCTIONAL ISOCYANATE-REACTIVE COMPOUND IN WHICH THE ISOCYANATE-REACTIVE GROUPS ARE OF DIFFERENT REACTIVITY IN AMOUNT SUCH THAT THERE IS ONE MOLEXULE OF SUCH COMPOUND FOR EACH ISOCYANATE GROUP STILL PRESENT.
Inventors
- 👤 R Aitken
Bibliographic Details
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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) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |