EXPANDABLE RESIN COMPOSITION FOR PRODUCTION OF ELECTRIC WIRE COVERED WITH POLYETHYLENE HIGHLY EXPANDED BY INERT GAS BLOWING AND INSULATED ELECTRIC WIRE PREPARED BY COVERING THEREWITH

摘要

PROBLEM TO BE SOLVED: To obtain a resin composition which, when extruded with a single- screw extruder, gives a foamed body having a high expansion ratio and a uni form fine cell structure by an inert gas blowing process by kneading a high- density polyethylene, a specified low-density polyethylene, a polypropylene, a polysiloxane/polyether block copolymer, and a nuclear forming agent. SOLUTION: This composition is obtained by mixing 100 pts.wt. high-density polyethylene having a melting point of 127-136 deg.C, a density of 0.945-0.968 g/cm3 and a melt flow rate of 0.1-10.0 g/10 min with 20-150 pts.wt. high-pressure process low-density polyethylene having a density of 0.915-0.925 g/cm3 and a melt flow rate of 0.1-10.0 g/10 min and 0.1-5 pts.wt. polysiloxane/polyether block copolymer of formula I, and 0.02-5 pts.wt. nucleator comprising azodicarbonamide and/or talc and kneading the mixture at a temp. of 145-165 deg.C. In the formula, R is a monovalent alkyl or the like; X is a group of formula II; (m) is 5-300; (t) is 2 or 3; (s) is 5-100; and (n) is 2-20.