REMOVAL OF VOLATILE SUBSTANCE FROM THERMOPLASTIC RESIN AND VENT TYPE TWIN-SCREW EXTRUDER

摘要

PURPOSE: To prevent the deterioration of physical properties of a thermoplastic resin and to improve volatilization efficiency. CONSTITUTION: A cylinder 1 is equipped with a raw material port 3, a first vent hole 4a and a second vent hole 4b successively provided from the upstream part of the cylinder so as to leave intervals and first and second pressure introducing ports 7a, 7b for introducing a volatilization agent are respectively provided on the upstream side of the first and second vent holes 4a, 4b. A first mixing element 6a is provided to two screws arranged in the cylinder 1 so as to extend from the vicinity on the upstream side of the first pressure introducing port 7a to the vicinity on the upstream side of the first vent hole 4a and resistance elements 5a, 5b are provided to the upstream and downstream ends of the first mixing element 6a. A second mixing element 6b and resistance elements 5a, 5b are also provided between the second pressure introducing port 7b and the second vent hole 4b.