PRODUCTION OF TUBULAR THERMOPLASTIC RESIN FOAM AND EXTRUSION MOLD

摘要

PROBLEM TO BE SOLVED: To produce tubular thermoplastic resin foam having a thin skin layer and to provide an extrusion mold. SOLUTION: A molten tubular member of a thermoplastic resin compsn. 1 containing a foaming agent is extruded from an extrusion mold and foamed while the outer diameter thereof is prescribed by a foaming mold 16 to produce tubular thermoplastic resin foam having a skin formed to the outer surface thereof. In this manufacturing method, the extrusion mold 14 is constituted of an outer mold 13 and a core 12 and the outer mold 14 is divided into an upstream outer mold 13a and a downstream outer mold 13b through a heat insulating material 15 in an extrusion direction and both outer molds 13a, 13b can be thermally regulated in temp. independently and the upstream outer mold 13a has heating molding function and the downstream outer mold 13b has skin forming function.