MANUFACTURE OF FOAMED FLUOROPLASTIC INSULATED WIRE

摘要

PURPOSE:To enable a thin and foamed insulated-covering to be formed by using a specified tetrafluoroethylene-perfluoro alkyl vinyl ethel-copolymerizate as a fluoroplastic. CONSTITUTION:A tetrafluoroethylene-perfluoro alkyl vinyl ethel-copolymerizate, which has the critical shearing speed of not less than 80 (sec)-1, is used as a fluoroplastic, and then, it is introduced into an extruding machine, where it is molten, and at the same time, a foaming agent is dissipated uniformly, before a foaming fluoroplastic, which has the extent of foaming of not less than at least 60%, is extrusion-coated around the outer periphery of a conductor. Thereby, a vast number of fine cells can be distributed uniformly, an insulated wire provided with a thin and low-density plastic foamed covering can be formed at the high speed.