| 摘要 |
<p>PURPOSE:To obtain a magnetic recording medium causing no curl, having high traveling performance, and smooth head-touch by forming a magnetic layer of a ferromagnetic material on an aromatic polyimide film. CONSTITUTION:An aromatic diamine component consisting of >=30mol% p- phenylenediamine and 0-70mol% diaminodiphenyl ether is copolymerized with a tetracarboxylic acid component consisting of biphenyltetracarboxylic acid dianhydride and pyromellitic acid dianhydride, and a soln. of the resulting aromatic polyamic acid is formed into a film and subjected to imidation to produce an aromatic polyimide film. A magnetic layer of a ferromagnetic material is formed on the aromatic polyimide film as a base film. This base film has superior heat resistance and tensile elasticity, and since it is produced by copolymn., the coefft. of thermal expansion can be made nearly equal to that of the ferromagnetic material by properly regulating the ratio among the constituents.</p> |
