| 摘要 |
PURPOSE:To improve the durability of the medium by incorporating a specific compd. into a magnetic layer, thereby well holding this compd. in the magnetic layer and maintaining the effect as a lubricant over a long period of time. CONSTITUTION:The compd. expressed by formula I (where X is an arom. group or alicyclic hydrocarbon group; R<1>, R<2> are 7 to 31C carbon-contg. group which may be the same group or the groups different from each other) is incorporated into the magnetic layer. The bivalent group: X existing in the dicarboxylic part of this compd. as aliphat. acid ester (dicarboxylate) consists of the arom. group or the alicyclic hydrocarbon group and, therefore, this X part is well held in the magnetic layer and the leaching to the surface hardly arises. The magnetic layer is thus strong to rubbing by a head, etc. Consequently, the effect as the lubricant is maintained over a long period of time and the durability thereof is improved. |
