| 摘要 |
PURPOSE: To improve all of wear resistance, traveling property and electromagnetic characteristics by using spherical silica particles and other inorg. particles having specific grain sizes at specific ratios as a lubricant at the time of producing the film. CONSTITUTION: The spherical silica particles having the average grain size of 0.03 to 2μm at 0.01 to 2wt.% and the other inorg. particles having the average grain size of 0.06 to 4μm at 0.03 to 5wt.% as the lubricant are incorporated into the polyester by the weight of the polyester to be used at the time of producing the polyester. In such a case, the smoothness and slippery property of the polyester film for magnetic recording media are improved. In such a case, the traveling property, wear resistance, electromagnetic characteristics and drop-out characteristics are improved if the film is so formed as to satisfy the conditions 1<=[D2 /D1 [<=2, 3<=[W2 /W1 [<=5 (D1 and D2 are respectively the average grain sizes of the spherical silica and the other inorg. particles, W1 and W2 are respectively the amt. of the spherical silica and the other inorg. particles to be added). |
