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US5051320A Magnetic recording medium 失效
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Magnetic recording medium
摘要:
A magnetic recording medium comprises a non-magnetic support having provided thereon a lower magnetic layer having a thickness of 2.5 .mu.m or higher and an upper magnetic layer having a thickness of 2 .mu.m or lower in this order, wherein both the upper and lower magnetic layers contain ferromagnetic particles, and the lower magnetic layer contains carbon black having an average primary particle diameter of less than 20 .mu.m in the amount of from 1.0 to 20 parts by weight per 100 parts by weight of the ferromagnetic particles contained in the lower magnetic layer, and the upper magnetic layer contains carbon black having an average primary particle diameter of at least 40 .mu.m but less than 80 .mu.m in an amount of from 0.1 to 10.0 parts by weight per 100 parts by weight of the ferromagnetic particles contained in the upper magnetic layer, but less than the amount of carbon black used in the lower magnetic layer.
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