PURPOSE: To enable to perform a uniformly kneaded and dispersed extrusion by the movement of a liquid phase as a result of rotation, by a method wherein 2 types of grooves are formed in a kneading part of a screw, one groove forms the deepest part, the other forms the shallowest part, and the grooves at a start and a terminal are formed with the same depth as that of the groove at a connection.
CONSTITUTION: A liquid phase 31 in a screw groove 18 flows over a sublight 15 into a screw groove 17 with the rotation of a screw. Thus, at a spot in the proximity of the deepest position (b) and the shallowest position (b') at an angle of 270°, the inside of the groove 17 is almost filled with the liquid phase 31, and a solid phase 32 is almost left in the groove 18. The groove 18 is brought into the shallowest depth at the position (b'), but a shearing action is exerted on the solid phase 32 left therein, whereby a fusing of the solid phase 32 proceeds efficiently, and the solid phase 32 is perfectly melted at a position (e'). Meanwhile, the groove 17, being filled with the liquid phase 31, is gradually deepened, and thereby a less shearing action is exerted. This prevents the temperature of the liquid phase 31 from rising to the value higher than necessary and eliminates the possibility of deterioration of the resin.
NAKAMURA KAZUYUKI
SAKAI TADAKI
