ELECTRICAL INSULATING MEMBER, POWER CABLE, AND CONNECTING MEMBER FOR POWER CABLE

摘要

PROBLEM TO BE SOLVED: To enhance AC characteristic and withstand voltage characteristic by using a resin composition, containing a syndiotactic polypropylene whose syndiotactic pentad rate is a specific value or more and an ethylene-α-olefin copolymer, for an electrical insulating member or an insulating layer. SOLUTION: 50 to 95wt.% syndiotactic polypropylene(s-PP) with a syndiotactic pentad rate of 0.7 or more is prepared. The polypropylene and 5 to 50wt.% ethylene-α-olefin copolymer in which theα-olefin has 4 to 12 carbons are kneaded together at 180 deg.C using a roll mill to obtain a resin composition. The resin composition is melted and molded at 180 deg.C for fifteen minutes in a compression molding machine and is continuously extruded by an electrical insulating member of a predetermined thickness or by an extruder onto a copper stranded conductor at about 180 deg.C to cover the conductor to form a cable, or is extrusion molded to form a reinforcement insulator used for connecting cable. Thus an insulating member is obtained which has high AC characteristic and impulse withstand voltage characteristic and is excellent in low-temperature brittleness.