| 摘要 |
PROBLEM TO BE SOLVED: To provide a slippery multilayer film having high physical property.SOLUTION: There is provided a film roll obtained by winding a multilayer polyimide film for an insulative substrate around a winding roll. The multilayer polyimide film is formed by laminating at least following (a) layer and (b) layer. In the multilayer polyimide film, a ratio of thickness of the (a) layer and the (b) layer:(a)/(b) is 0.01 to 0.1, thickness of the (b) layer is 2 μm to 40 μm and both of tensile elasticity in a longitudinal direction and that of a width direction is 6.0 GPa or more. (a) layer: a layer mainly containing polyimide containing 0.5 mass% to 50 mass% of an inorganic fine particle having an average particle diameter of 0.05 to 2.5 μm and having at least pyromellitic acid as a residue of aromatic tetracarboxylic acid and a benzoxazole structure as a residue of aromatic diamines. (b) layer: a layer mainly containing polyimine having the content of an inorganic fine particle of 0.1 mass% or less and at least pyromellitic acid as a residue of aromatic tetracarboxylic acid and a benzoxazole structure as a residue of aromatic diamines. |
