| 摘要 |
PURPOSE:To obtain a magnetic recording medium having excellent running stability and wear resistance of a back coating layer and having a particularly good video characteristic by providing the back coating layer contg. specific alkaline BaSO4 powder and alpha-Fe2O3 powder on the rear of a base having a magnetic layer on the main plane. CONSTITUTION:BaSO4 powder which is the dry powder prepd. by charging, for example, neutral BaSO4 powder manufactured by various methods into an aq. NaOH soln. and mixing the same then rinsing thoroughly the powder and of which the pH when said dry powder is dispersed into water is in a 7.5-10pH range is dispersed together with alpha-Fe2O3 powder having <=0.2mu average grain size into a resin binder soln. An additive such as carbon black is added thereto for preventing electrification, etc. thereby preparing a coating liquid. Such coating liquid is coated on the rear of a base provided with a magnetic layer and is dried, by which a back coating layer is formed. The magnetic tape which has good running stability, has excellent wear resistance of the back coating layer, obviates the wear of a tape guide and has a good color SN ratio is thus obtd. |
