INSULATION WIRE AND MANUFACTURING METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide an insulation wire having suppressed crack of an insulation layer, high heat resistance, good adhesiveness with a conductor and inner adhesiveness.SOLUTION: There is provided an insulation wire having a conductor, an insulation layer arranged on an outer periphery thereof and a self fusion layer arranged on the insulation layer and containing a resin with the softening temperature of 280°C or less. The insulation wire has a cross section shape having a pair of long sides facing each other and a pair of short sides facing each other and having convex curvature toward an outside respectively, the insulation layer contains polyimide containing: a tetracarboxylic acid component unit (a) containing a biphenyl tetracarboxylic acid anhydride unit of 40 to 80 mol%, a benzophenone tetracarboxylic acid anhydride unit of 10 to 20 mol% and a pyromellitic acid anhydride unit of 10 to 50 mol%; and a diamine component unit (b).SELECTED DRAWING: Figure 1 【課題】絶縁層のひび割れが抑制され、且つ高い耐熱性と、導体との良好な密着性や層内密着性とを有する絶縁電線を提供する。【解決手段】導体と、その外周上に設けられた絶縁層と、前記絶縁層上に設けられ、軟化温度２８０℃以下の樹脂を含む自己融着層とを有する絶縁電線であって、前記絶縁電線は、互いに対向する一対の長辺と、互いに対向し、それぞれ外側に向かって凸状に湾曲した一対の短辺とを有する断面形状を有し、前記絶縁層は、ビフェニルテトラカルボン酸無水物単位４０〜８０モル％と、ベンゾフェノンテトラカルボン酸無水物単位１０〜２０モル％と、ピロメリット酸無水物単位１０〜５０モル％とを含むテトラカルボン酸成分単位（ａ）と、ジアミン成分単位（ｂ）とを含むポリイミドを含む、絶縁電線。【選択図】図１