Orientierter Polyesterfilm

摘要

A biaxially oriented polyester film comprising silica particles (A) having an average secondary particle size of 50-200 nm, an average primary particle size ratio (length/breadth) of 1.25-3.0 and the ratio of average primary particle size/standard deviation of primary particle size (d/ sigma ) of 0.5-5.0 in a proportion of 0.01-1% by weight, and inactive particles (B) having an average particle size of 300-1500 nm in a proportion of 0.01-1% by weight. The polyester film of the present invention can be adapted to a high speed feeding of a film or tape in the production line and stand the use of economical parts in an attempt to achieve decreasing the costs of tapes.