Fujikura Limited

Nof Corporation

Izumi Ishikawa

Isao Takahashi

Akira Yoshino

Hideo Sunazuka

Masatake Hasegawa

Motohisa Murayama

Tohru Takahashi

Kazuhiko Goto

Kenji Matsui

Shiro Nakayama

Toshio Niwa

Mitutaka Tanida

Thoru Nakatsuka

Hiroyuki Miyata

A polyethylene composition which is useful in insulations and joints of extra-high voltage power cables, and in which a cross-linking agent, comprising an organic peroxide subjected to purification processing, and an antioxidant, are blended, wherein the cross-linked composition has a dielectric loss tangent (tan.delta.) of less than or equal to 0.07% at a temperature of 90.degree. C. and under an electric field stress of 20 kV/mm. This polyethylene composition exhibits little dielectric loss, even at high temperatures or high electric field stresses, and is optimally employed in insulations and joints for extra-high voltage power cables of 275 kV or more.

Polyethylene composition for use in insulations and joints of extra-high

The present invention relates to an insulated wire comprising a conductor and at least two insulating layers provided on the outer periphery of the conductor. The inner insulating layer is provided directly or via another insulation on the outer periphery of the conductor and comprises a polyolefin compound containing 20 to 80 parts by weight of at least one substance selected from ethylene .alpha.-olefin copolymer, ethylene .alpha.-olefin polyene copolymer (.alpha.-olefin having the carbon numbers of C.sub.3 -C.sub.10, polyene being non-conjugated diene). The outer insulating layer is made primarily of a heat resistant resin which contains no halogen and which is a single substance or a blend of two or more substances selected from polyamide, polyphenylene sulfide, polybutylene terephthalate, polyethylene terephthalate, polyether ketone, polyether ether ketone, polyphenylene oxide, polycarbonate, polysulfone, polyether sulfon, polyether imide, polyarylate, polyamide, or a polymer alloy containing such resin as the main component.

Electric insulated wire and cable using the same

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Tokyo, Japan

Izumi Ishikawa