| 摘要 |
PURPOSE:To provide a magnetic recording medium having good wear resistance and S/N, high reproduced output and good shelf life by contg. a polymer compd. of a specific average mol. wt. which has a monomer unit having a negative org. group and of which the org. group forms a salt as a component for the copolymn. CONSTITUTION:For example, a carboxylic group, residual phosphoric acid group, etc. are preferable as a negative org. group in a monomer unit A having the negative org. group as a component for copolymn. of a polymer compd. An ammonia salt, amine salt, etc. are preferable as the salt thereof and, for example, an acrylic acid, maleic anhydride, etc. are preferable as the monomer unit A. For example, styrene and styrene deriv. are exemplified as a monomer unit B except the unit A of the polymer compd. The weight-average mol. wt. of the polymer compd. is made <1,000. Such compd. is dissolved in a solvent and magnetic powder is dipped in such soln. at a prescribed ratio. The mixture is filtered or subjected to a drying treatment involving evaporation after stirring and mixing or the compd. may be added to the magnetic powder in the stage of dispersing the same. |
