| 摘要 |
PROBLEM TO BE SOLVED: To continuously obtain a polyurethane with improved releasability at low melt temperatures, having excellent uniformity and melt characteristics, and useful for e.g. injection-molded products, through vigorously mixing the corresponding prepolymer with a chain extender. SOLUTION: This polyurethane is obtained through the following processes: the corresponding isocyanate-terminated prepolymer is vigorously mixed with a chain extender at a temperature of (200 deg.C, for example, within 5 s, into a reaction mixture which is then converted to the aimed polyurethane capable of melt treatment under quasi-adiabatic reaction conditions in an twin-screw extruder; wherein it is recommended that the above extruder has screw shafts rotating in the same direction and an either cooled or non-heated barrel. |
