Magnetic recording medium comprising a polar group containing resin or compound and a methyl iso ester lubricant prepared from a methyl iso acid or methyl iso alcohol or both

摘要

A magnetic recording medium is disclosed, which comprises a non-magnetic support having provided thereon a magnetic layer mainly composed of a ferromagnetic powder and a binder resin comprising (i) a polymer having at least one polar group selected from -SO3M1, -OSO3M1, -COOM1, wherein M1 represents a hydrogen atom, Li, Na or NR4 (wherein R represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkanol group), and M2 represents a hydrogen atom, Li, Na, an alkyl group, or NR4 (wherein R has the same significance as defined above); or (ii) a compound having at least one polar group selected from -SO3M3, -COOM3, and -PO3(M3)2 (wherein M3 represents a hydrogen atom, an alkali metal, or an ammonium group) and containing at least one carbon-carbon unsaturated bond in the molecule, said magnetic layer containing at least one ester compound represented by following formula (I), (II), or (III), and when the binder resin comprises the compound (ii), the magnetic layer is irradiated by radiations: (I) (II) (III) wherein R1 represents a straight chain or branched alkyl group having from 7 to 29 carbon atoms or a straight chain or branched alkenyl group having from 7 to 29 carbon atoms; l, k, m, and n represents an integer; l and n each is at least 2, and the sum of n and m and the sum of k and l are from 7 to 33.