| 摘要 |
PURPOSE:To prevent a magnetic recording medium from causing defects and generating noise owing to a broken piece and dust produced by wear by forming the inner wall of a ball mill pot for kneading a magnetic coating material and plastic balls used in the pot with the same material so as to inhibit the wear of the inner wall and the balls. CONSTITUTION:When a magnetic coating material 2 consisting essentially of magnetic powder, a solvent and resin is kneaded in a ball mill pot 1, the inner wall of the pot 1 is made of the same material such as nylon as plastic balls 3. When the balls 3 and the inner wall are made of the same material, dust is not produced in large quantities by wear due to difference in material. The magnetic coating material is hardly mixed with dust produced by wear, so a magnetic disk or the like is prevented from causing defects and generating noise. |
