| 摘要 |
PURPOSE:To provide superior dimension stability and heat resistance and improve smoothness of a surface by turning a specified polyether copolymer into a non-crystalline film, biaxially orienting the film at the specified magnification to turn the same into an oriented film and heat treating the oriented film at the temperature of glass transition or higher and the crystallization fusion point or lower. CONSTITUTION:An electric insulating film is constituted of the repeating unit represented by the formula I and the repeating unit represented by the formula II. A polyether copolymer, in which the ratio of repeating unit represented by the formula I is the molar ratio of 0.15-0.40 and the melt viscosity at the shearing speed of 10sec<-1> at 400 deg.C is 500-600000 poise, amorphous is turned into an amorphous film. The amorphous film is biaxially oriented by the magnification beyond three times as much both in the vertical and horizontal directions to form an oriented film. Then the oriented film is heat treated once or more to the glass transition temperature or higher of the polyether copolymer and below the temperature of crystallization fusion point to form a heat fixing biaxially oriented film of the polyether copolymer. |
