Continuous process for polymerizing urethane prepolymers
Abstract
Abstract THIS INVENTION IS A CONTINUOUS PROCESS FOR THE PRODUCTION OF SOLUTIONS OF SUBSTANTIALLY LINEAR POLYURETHANES USEFUL TO PRODUCE FILAMENTS AND OTHER ARTICLES. IN THE PROCESS THERE IS PASSED INTO A FIRST REACTION ZONE AN ORGANIC SOLVENT, A SUBSTANTIALLY LINEAR ISOCYANATE-TERMINATED PREPOLYMER AND AT LEAST ONE CHAIN EXTENSION AGENT HAVING AT LEAST TWO HYDROGEN ATOMS TO PRODUCE A SOLUTION OF A SEMI-POLYMER. THE PREPOLYMER IS PRESENT IN THE FIRST REACTION ZONE IN AN AMOUNT LESS THAN THE STOICHIOMETRICAL AMOUNT, SO THAT THERE IS OBTAINED IN THE FIRST REACTION ZONE A DEGREE OF REACTION IN EXCESS OF ABOUT 80%, BUT LESS THAN 100%. THE SEMI-POLYMER IS THEN PASSED CONTINUOUSLY INTO A SECOND REACTION ZONE WHERE THERE IS ADDED AN AMOUNT OF PREPOLYMER SUFFICIENT TO COMPLETE THE POLYMERIZATION OF THE SEMI-POLYMER. THE PROCESS ALSO INVOLVES THE RECYCLE TO THE FIRST REACTION ZONE OF A PORTION OF THE SEMI-POLYMER SOLUTION PRODUCED THEREIN.
Inventors
- 👤 Henri Albert Mommaerts
- 👤 Wilfred Jean Melaerts
Bibliographic Details
Claims Analysis
Total Claims: 0References 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) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |