| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a thermoplastic polyurethane scarcely generating an outgas or a low-molecular weight substance and effectively usable as a molding material for parts of electrical and electronic devices, or the like. SOLUTION: A prepolymer reaction of a polyol with a diisocyanate in an excessive molar amount is carried out under pressurized conditions of an inert gas. The prepolymer reaction is continued under conditions of a reduced pressure from the time when a theoretical NCO% attains. A urethanizing reaction is then conducted with a chain extender and the resultant hot cured urethanized material is subsequently granulated with an extruder while carrying out suction under conditions of a reduced pressure to produce the granulated material of the thermoplastic polyuerthane. |
