| 摘要 |
PURPOSE:To obtain a magnetic recording medium having low light transmittability, durability, etc. by providing a back layer formed by dispersing pulverous powder of the nonmagnetic black composite oxide made by calcining carbon black and compd. contg. >=2 kinds among specific four kinds of elements into a binder to a magnetic recording medium. CONSTITUTION:A back layer for a magnetic tape, magnetic sheet, etc. is formed by dispersing the pulverous powder of the black composite oxide obtd. by calcining carbon black and a compd. contg. at least >=2 kinds among Fe, Mn, Cu and Cr into a binder at about 30-80wt% by 100pts.wt. back layer and at about 80: 20-20:80 weight ratio between the carbon black and the black composite oxide. The poor dispersibility and insufficient mechanical strength with the carbon black alone and thus improved and the magnetic recording medium having a good antistatic property and runnability, low light transmittance and excellent wear resistance and durability is obtd.
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