SCREW FOR EXTRUDER, EXTRUDER, AND EXTRUSION METHOD

摘要

The present invention provides extrusion technology that applies stretching action to all of a raw material that is conveyed by an extruder (screw) without leakage and without increasing the length of the screw by equipping the screw itself with a function for applying stretching action to the raw material, thereby improving the kneading degree of said raw material. A conveyance section (22), a barrier wall section (23), and a passage (37) are provided across a plurality of locations in a section of a screw main body (11) that has a kneading section (11c) provided thereto. The passage is provided to the interior of the screw main body in at least one of said locations and comprises an inlet (38) and an outlet (40). The inlet opens such that raw material that has been subjected to an increase in pressure as a result of the barrier wall section restricting the conveyance of said raw material flows into said inlet. The passage is configured so that the raw material that flows in from the inlet flows in the opposite direction of the conveyance direction of the conveyance section. The outlet opens on the outer circumferential surface of the screw main body at a position that is separated from the conveyance section at which the inlet opens.