PURPOSE: To prevent defects at the time of terminal processing by laser maintaining excellent mechanical characteristics, by longitudinally applying or helically winding the multi-filament of specific plastic in the direction of the length onto the circumference of a foamed insulation layer to cover a copper wire.
CONSTITUTION: A foamed insulation layer 2 like a mixture of high-density and low-density polyethylene having an expansion ratio of not less than 60% where the transmission rate of a signal is not lowered is formed on the circumference of a conductor 1. One to six pieces of multi-filaments 3 of polyethylene and the like without aromatic rings in molecular structure causing yellowing and carbonization at the time of laser cutting are longitudinally applied to or helically wound on the circumference of the layer 2 to provide the mechanical strength of such a degree that collapse and break may be prevented at the time of manufacture or processing. An ultraviolet ray curing resin 4 of proper thickness is applied thereto and then hardened by radiating ultraviolet rays thereon for film fixation.
YAMAMOTO SHOJI
OISHI YOSHIAKI
