| 摘要 |
PURPOSE:To provide the titled medium having an excellent electromagnetic conversion characteristic by forming a binder of a resin component which contains a copolymer contg. the repeating unit derived from a hydroxy straight chain alkyl sulfonic acid or the ester of the alkali metal salt thereof and (meth) acrylic acid and the repeating unit derived from a vinyl chloride. CONSTITUTION:The binder consists of the resin component which contains the copolymer contg. the repeating unit derived from the hydroxy straight chain alkyl sulfonic acid or the ester of the alkali metal salt thereof and (meth) acrylic acid and the repeating unit derived from the vinyl chloride. The sulfonic acid group which is not directly bound with the main chain of the copolymer constituting the binder is incorporated into the binder and since the sulfonic acid group is chemically stable, the cutting of side chains in the stage of preparing a magnetic coating compd., etc. is decreased and the dispersion condition of the magnetic coating compd. and the ferromagnetic powder in a magnetic layer formed by coating said compd. is extremely improved. The group which hinders the free rotation of the sulfonic acid group does not exist in the side chains and therefore, the affinity possessed by the sulfonic acid group is not limited in structure.
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