Patent ID: 8790558
Filing Date: 2014-07-29
Classification: B29C,H01G

Abstract:
1. A method for manufacturing a film for film capacitors having a thickness of 10 microns or less, comprising the successive steps of: mixing and preparing a forming material composed of a thermoplastic resin composition; melting and extruding the forming material to a film through a T-die; pinching and cooling the film between a pressure roll and a cooling roll having a rough surface for forming a uniform rough surface on the film, wherein the rough surface of the cooling roll has (σ/Ra) of 0.2 or less, and the uniform rough surface of the film has (σ/Ra) of 0.2 or less, where (Ra) is an arithmetic average roughness defined by a method specified in JIS B 0601 2001, and (σ) is a standard deviation; and rolling up the cooled film onto a winding tube in a winding unit, wherein the film has surface properties of (Ra) of 0.2 microns or less, (Rz/Ra) of 10 or less and a dynamic friction coefficient of 1.5 or less, where (Rz) is a maximum height defined by the method specified in JIS B 0601 2001.