| 摘要 |
PURPOSE:To offer a magnetic recording medium by which a coefficient of friction does not increase, also scraping, etc. are not generated, an adhesive strength of a back layer is good, and a running durability is good, by using two kinds of powder of a fine particle in which an average particle size of carbon black of the back layer is within a specified range, and a rough particle, and constituting so that a ratio of the carbon black and a binding material is within a specified range. CONSTITUTION:As for carbon black of a fine particle of 30-300mmu and carbon black of a rough particle of 150-500mmu, 99.5:0.5 through 50:50 is desirable, and preferably, 99:1-60:40 is desirable. Also, as for a ratio of carbon black of a back layer and a binding material, 1/0.5-1/3.5 is desirable by a weight ratio. Its more desirable ratio is 1/0.8-1/3.0. As for the back layer, the carbon black is formed by combining the fine particle of 30-100mmu and the rough particle of 150-500mmu, and also a good result is shown within a range in which the P/B ratio is 1/0.5-1/3.5. |
