| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester film which has excellent winding properties, hardly causes a track shift and exhibits excellent electromagnetic conversion characteristics and less dropout when used as the magnetic recording medium, and therefore is useful as a base film of a magnetic recording medium, particularly a magnetic linear digital recording medium. SOLUTION: The biaxially oriented polyester film has an average surface roughness WRa at the center plane of 4-12 nm and Young's moduli of 6.5-12 GPa in the longitudinal direction and 5-8 GPa in the width direction, and contains 0.005-0.05 wt% of inactive particles having an average particle size of 0.45-0.65μm, 0.005-0.05 wt% of inactive particles having an average particle size of 0.20-0.40μm and 0.03-0.29 wt% of inactive particles having an average particle size of 0.02-0.15μm, each having a relative standard deviation of the particle size distribution of at most 0.2. COPYRIGHT: (C)2006,JPO&NCIPI |
