Biaxial orientierter Mehrschichtfilm aus Polyester

摘要

A biaxially oriented, laminated polyester film has a lamination structure with at least two layers. At least one of the outermost layers of the film is a thin laminated layer A having a thickness of not more than 3 mu m. In the layer A, mono-dispersed particles are present at a very small content of not less than 0.01% by weight and less than 0.3% by weight. The mono-dispersed particles have a mean degree of agglomeration of less than 5 and a mean primary particle diameter of not less than 0.05 mu m and not more than 3 mu m. A relative standard deviation of height distribution of protrusions formed on the surface of layer A is not more than 1.2. When the polyester film is used as a base film for magnetic recording media, the abrasion resistance of the film surface at a high speed can be greatly increased.