Lubricating agent and magnetic recording medium comprising the same

A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer provided on at least one surface of the substrate, and a lubricating agent comprising:

• (A) at least one alkylene oxide derivative having an alkylene oxide group and an ester moiety or an ammonium salt moiety, which is represented by the following general formula (1), (2), (3) or (4):
• R.sup.1 --O--(R.sup.2 O).sub.m --R.sup.3 --COO-R.sup.4 ( 1)
• R.sup.1 --O--(R.sup.2 O).sub.m --R.sup.3 --COONH.sub.3 --R.sup.4( 2)
• R.sup.4 --OCO--R.sup.3 --O--(R.sup.2 O).sub.m --R.sup.3 --COO--R.sup.4( 3)
• R.sup.4 -NH.sub.3 OCO-R.sup.3 -O-(R.sup.2 O).sub.m -R.sup.3 -COONH.sub.3 --R.sup.4 ( 4)
• wherein R.sup.1 is a hydrocarbon group having 1 to 26 carbon atoms or a hydrogen atom,
• R.sup.2 is a hydrocarbon group having 1 to 6 carbon atoms,
• R.sup.3 is a hydrocarbon group having 1 to 26 carbon atoms,
• R.sup.4 is a hydrocarbon or fluorocarbon group having 1 to 26 carbon atoms, and m is from 1 to 12, and
• (B) at least one aliphatic amine represented by the following general formula (5):
• R.sup.5 N(R.sup.6)R.sup.7 ( 5)
• wherein R.sup.5 is a hydrocarbon group having 1 to 26 carbon atoms, and each of R.sup.6 and R.sup.7 is a hydrocarbon having 1 to 26 carbon atoms or a hydrogen atom, wherein said lubricating agent is in or on the magnetic layer.