| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester film roll for a magnetic recording medium capable of manufacturing a magnetic resin tape having a stable high quality with no differences in the lateral and longitudinal directions of a base film. SOLUTION: The polyester film roll for the magnetic recording medium is constituted by providing a film, which contains fine particles with an average particle size of 6-30 nm and an organic compound, on the magnetic surface side of a polyester film and providing fine surface projections due to the fine particles on the film in a density of 10,000,000-100,000,000/mm<SP>2</SP>and characterized in that the ratio of standard deviation with respect to the average number of the fine surface projections arbitrarily measured at seven or above points in the lateral direction of the polyester film is 0.10 or below, the ratio of standard deviation with respect to the average value of center line average surface roughness (Ra) is 0.12 or below, the ratio of standard deviation of the fine surface projections measured at an interval of 1,000 in the longitudinal direction of the polyester film is 0.12 or below and the ratio of standard deviation with respect to the average value of the surface roughness (Ra) is 0.15 or below. COPYRIGHT: (C)2008,JPO&INPIT |
