| abstract |
(57) [Summary] [Object] To provide a biaxially oriented polyester film having excellent surface properties, abrasion resistance and running properties. [Structure] A biaxially oriented polyester film is characterized by containing 0.005 to 2.0% by weight of vaterite-type calcium carbonate which simultaneously satisfies the following formulas. ## EQU1 ## d 25 / d 75 ≤2.00 ... 0.07 ≤ d 50 ≤ 1.50 ... 1.6 ≤ S ≤ 40.0 ... 2.4 ≤ d 50 × S ≤ 7.0 ... [above In the formula, d 25 , d 75, and d 50 are 25% of the total volume and 7%, respectively, when the integrated volume of the particle group is measured from the large particle side. The particle diameter (μm) corresponding to 5% and 50% is shown, and S shows the specific surface area (m 2 / g). ] |