MAGNETIC RECORDING MEDIUM AND ITS MANUFACTURE

PURPOSE:To obtain a magnetic recording medium which has a high recording density and a high recording capacity by a method wherein the thin film magnetic layer of the magnetic recording medium has a thickness not larger than 0.7mum and its surface smoothness and the surface resistivity are controlled within required ranges. CONSTITUTION:A magnetic recording medium is composed of a nonmagnetic supporter and a magnetic layer which is formed on the supporter and contains ferromagnetic powder and carbon black dispersed in binder. The thickness of the magnetic layer is not larger than 0.7mum. The carbon black has a carbon structure and an oil absorption rate of 300-500ml/100g. Further, the contents of the carbon black in the magnetic layer is 3-7 wt.pt. for 100 wt.pt. of the ferromagnetic powder. In the manufacturing process of magnetic coating for forming the magnetic layer of the magnetic recording medium, material composed of the ferromagnetic powder, the carbon black, the binder and organic solvent is kneaded by a pressurized kneader. First, the binder and the organic solvent are supplied to the kneader and then the carbon black is supplied and kneaded and then the ferromagnetic powder is supplied and kneaded again. The magnetic recording medium which has the magnetic layer having a thickness not larger than 0.7mum and has a high recording density and a high recording capacity can be obtained.