| 摘要 |
<p>PURPOSE:To obtain a magnetic recording medium having excellent running durabiity by forming a magnetic layer contg. ferromagnetic powder dispersed into a binder contg. a specific polyurethane resin on a non-magnetic substrate. CONSTITUTION:The polyurethane resin which is expressed by formula I and has the repeating unit derived from diol is incorporated intot the binder of the magnetic recording medium having the nonmagnetic substrate and the magnetic layer contg. the ferromagnetic powder dispersed in the binder formed thereon. In the formula, R<1>-R<4> may be the same or different from each other and denote hydrogen atom, satd. or unstad. aliphat. group, arom. group, and alicyclic. group of 1-5C, at least three substituents among R<1>-R<4> are not hydrogen atoms. l Is 1-3, m is 0-2, n is 1-3, p is 1-3 integer. The unit expressed by formula I among the repeating units of the diol constituting the polyurethane resin is >=20mol% and the polyurethane resin is preferably incorporated in the binder at >=10wt% of the total weight of the binder.</p> |
