| 摘要 |
PURPOSE:To improve the surface smoothness of a magnetic layer and the filling degree of a magnetic body and to obtain satisfactory radio frequency output and audio output, by incorporating 2 kinds of carbon black having different grain sizes in the magnetic layer. CONSTITUTION:Fine-grained carbon black having <10mmu average primary grain size is mixed with coarse-grained carbon black having 50-120mmu average primary grain size in 95/5-5/95, preferably 70/30-30/70 weight ratio, and the mixture is incorporated into the magnetic layer of a magnetic recording body to be formed on a nonmagnetic support by coating. The preferred amount of the carbon black mixture to be added is 1-20pts., especially 3-15pts. per 100pts. magnetic body. |
