| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester film having a good rolled shape without detriment to the transparency by facilitating the removal of air in the interspaces among film layers when the film is rolled into a roll. SOLUTION: The biaxially oriented polyester film contains inorganic particles A and B different in particle shape, wherein the primary mean particle diameters (DA, DB) of the inorganic particles A, B are each 1.0-3.5μm, the particle diameter ratio (DA/DB) is 1.0 to 3.0, the mixing ratio of inorganic particles A, B (A/B) is (30:70) to (80:20) (by mass), and the three-dimensional surface roughness values Sa, Sc, Sz of the film satisfy formula (1): 30<=(Sc.Sz)/(Sa)1/2<=100, formula (2): 0.020<=Sa<=0.040, formula (3): 1.0<=Sz<=1.5, and formula (4): 5<=Sc<=15 [wherein Sa is the central surface average roughness (μm); Sz is the ten-point average roughness (μm); and Sc is the number of peaks (the number/0.1 mm2)].
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