| 摘要 |
PURPOSE:To improve the mechanical strength at the high temperature by forming an insulating covering with a composition material containing tetrafluoroethylene copolymer and vinylidene fluoride copolymer. CONSTITUTION:A covering layer made of a composition material containing tetrafluoroethylene-propylene copolymer A and vinylidene fluoride copolymer B with the crystal melting point of 80-140 deg.C at the A/B weight ratio of 90/10-50/50 is provided around a conductor, and this covering layer is bridged. The number average molecular weight of the tetrafluoroethylene-propylene copolymer is preferably set to 20,000-150,000 in view of the extruding property and mechanical strength, if the number average molecular weight is too large, cracks are liable to occur on a molding, on the other hand if it is too small, the mechanical strength is liable to become insufficient. A covering layer excellent in mechanical strength at the high temperature can be thereby obtained.
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