Melt extrusion processing method of thermoplastic resin

摘要

A melt extrusion processing method of a thermoplastic resin, wherein a thermoplastic resin having a flow temperature of 200 DEG C. or higher is subjected to extrusion processing using a melt kneading type extruder in which a vent port is provided at a downstream position by length L from the most upper stream portion of a melt kneading type extruder screw and L/D is from 4 to 18 (wherein D indicates the screw diameter and D and L are in the same scale unit), while continuously sucking from the said vent port at a reduced pressure of lower then 660 mmHg. The invention provides a method which causes little resin degradation in an extruder to give an extruded article containing small amounts of discolored and degraded materials even when the processing is conducted for a relatively long time.