| 摘要 |
PROBLEM TO BE SOLVED: To obtain a biaxially oriented polyester film excellent in abrasion resistance and useful as a magnetic recording medium, etc., by including particles having specified particle diameter, specific surface area and relative standard deviation. SOLUTION: This biaxia1ly oriented polyester film includes 0.005-3wt.% hydroxyapatite particles having 20-2,000nm average particle diameter, 50-500m<2> /g BET specific surface area and <=0.5 relative standard deviation of the particle diameters. A film preferably has at least one layer comprising the objective film, and the thickness of the laminated layer of the film preferably has 0.01-3.0μm thickness and the relation between the average particle diameter (d) (nm) of the before particles and the layer thickness (t) (nm) of the before layer preferably satisfying the formula O.2d<=t<=10d. The particles preferably consists essentially of calcium phosphate and is represented by the chemical composition formula of Ca(PO4 )3 .OH. |
