| 摘要 |
PURPOSE:To improve magnetic conversion characteristics and to improve slipperiness, scratching resistance and chipping resistance by incorporating spherical silica particles having a specific grain size, grain size ratio, etc., and titanium oxide particles having a specific grain size and grain size distribution ratio into polyester. CONSTITUTION:The spherical silica particles dispersed and incorporated as a 1st component into the polyester have >=0.05mum and <=2mum average grain size and 1.0-1.2 grain size ratio (major diameter/minor diameter). The amt. of the particles to be added is 0.01-2wt.%. The anatase type titanium oxide particles to be dispersed and incorporated as the 2nd component therein have >=0.05mum and <=1mum average grain size and the grain size distribution ratio [gamma]expressed by the formula is in a 1.2-2.3 range. These particles are incorporated at 0.01-1wt.% into the polyester. Provision of the biaxially oriented polyester film for magnetic recording media having the excellent slipperiness, scratching resistance and chipping resistance is enabled even if the surface is flattened. |
