| abstract |
An object of the present invention is to provide a highly insulating film having high electrical characteristics (insulation breakdown voltage) and excellent handling properties such as heat resistance, winding resistance, and workability. The present invention provides a biaxially oriented film containing a styrenic polymer having a syndiotactic structure as a main constituent, the specific inert fine particles A, an antioxidant, and a polymer Y having a glass transition temperature Tg of DSC of 130 ° C or higher, respectively. It is a high insulating film containing refractive index of 1.5750 or more and 1.6350 or less in the thickness direction. |