| 摘要 |
<p>Disclosed is a magnetic recording medium good in production efficiency, paint stability and electromagnetic characteristics, and improved in running properties and durability, which has a magnetic layer formed on a surface side of a non-magnetic support and a backcoat layer formed on a back side thereof, in which said backcoat layer is formed by kneading a compounded composition comprising 50 parts to 120 parts by weight of carbon black (P) per 100 parts by weight of a resin binder (B) (P/B = 0.5/1 to 1.2/1), said carbon black (P) having an average particle size of 18 nm to 25 nm and a DBP oil absorption of 90 cc/100 g to 125 cc/100 g, 0.3 part to 2.5 parts by weight of large-sized carbon black or carbon graphite having an average particle size of 150 nm to 500 nm per 100 parts by weight of said carbon black, and a vinyl chloride copolymer as the resin binder, said copolymer containing at least amine-modified vinyl units and acidic functional group-containing vinyl units at the same time, so as to satisfy that the concentration of nonvolatile components is 45 to 60%, and that the P/B is 1.5/1 to 3.5/1, and then, dispersing the kneaded compound by dilution.</p> |
