| 摘要 |
PROBLEM TO BE SOLVED: To prepare a polyester film having an even surface, being excellent in running performances, abrasion resistance, and transparency and being applicable to various uses such as graphic arts, displays, packaging, transfer marks, photochemical processes, and electrical ones such as magnetic recording media and capacitors. SOLUTION: There is provided a polyester film containing 0.01-3.0 wt.% porous spherical silica particles having a mean particle diameter of 0.3-15μm, a sphericity ratio of 0.90-1.0 (as defined by formula I: sphericity ratio = projection area of particle/maximum-diameter-circle-equivalent area in projected surface of particles), a particle size distribution value of 1.2-2.5 (as defined by formula II: particle size distribution value = d10 /d90 (wherein d10 and d90 are particle diameters (μm) corresponding to 10% and 90% of the total volume as determined when the cumulative volumes of groups of particles are measured from the side of larger particles), and a specific surface area of 100-600 m<2> /g.
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