| 摘要 |
PROBLEM TO BE SOLVED: To provide a undirectionally rotating twin-screw extruder suppressing color change and carbonization of a thermal plastic resin caused by heat deterioration during a kneading process and suitable for obtaining the kneaded material of the thermal plastic resin excellent in color shade, and physical properties, tensile strength and tensile elongation, by injecting carbon dioxide during melting and kneading of the thermal plastic material to reduce the viscosity of the melted resin and prevent shear heating. SOLUTION: This undirectionally rotating twin-screw extruder has the specific torque of a gear box being 150-400 N.m/cm<3> , and the screw configuration of a first kneading zone comprising a zone A showing the highest pressure peak, a zone C showing a pressure peak lower than that of the zone A, and a zone B, which is a trough between the pressure peaks of the zones A and C, and arranging the zones A, B, and C in this order along the extrusion direction, and is equipped with an injection device for injecting carbon dioxide in the zone B. |
