BIAXIALLY ORIENTED POLYESTER FILM

摘要

PURPOSE:To obtain an optimum film used for a magnetic recording medium having low generation of powder in the case of using for a high speed VTR, etc., by incorporating particles in a layer made of a polyester and thus efficiently forming a surface protrusion of a broad shape which is scarcely shaved off. CONSTITUTION:The biaxially oriented polyester film is formed by laminating a layer (A layer) made of a polyester A containing particles at least on one surface of a layer (B layer) made of a polyester B in such a manner that a ratio H/D of a mean protrusion height H to protrusion diameter D of the surface of the A layer is in a range of 0.01-0.2, and number of the protrusions is 10<3>-10<6> pieces/mm<2>.