| 摘要 |
PURPOSE:To enhance the dispersibility at the time of prepn. of a coating compd. and to improve an output characteristic and noise characteristic by specifying the contact angle of magnetic powder with a prescribed solvent. CONSTITUTION:The magnetic recording layer is formed by the magnetic coating compd. essentially consisting of the magnetic powder (A) and the resin binder. The magnetic powder having 25-50dyne/cm surface tension and 0 deg. (degree) contact angle with the solvent is used for the component A. The powder of uniaxially anisostropic hexagonal ferrite which is subjected to a treatment for imparting a lipophilic property by a silane coupling agent, etc., is usable as the above-mentioned component A. The fit to the vehicle is improved too much and the coefft. of friction of the medium increases if the above-mentioned contact angle exceeds 0 deg. (degree) and, therefore, such angle is undesirable. |
