Magnetischer Aufzeichnungsträger hoher Dichte

摘要

A novel high density magnetic recording medium is disclosed. Said medium comprises a polyester film formed of a plurality of layers laminated by coextrusion and oriented by stretching, which simultaneously satisfies the conditions of the following relations (1) to (4); a back coat layer which is provided on the rougher surface side of said polyester film layer and whose surface roughness simultaneously satisfies the conditions of the following relations (5) and (6) ; and a magnetic film layer provided on the less rough surface side of said polyester film. Ra O.OO5 0.005 - Ra 9 0.015 0.003 - Ra wherein Ra stands for centerline average roughness ( mu m) of the less rough surface side of the polyester film; Ra stands for centerline average roughness ( mu m) of the rougher surface side of the polyester film; Ra stands for centerline average roughness ( mu m) of the surface of the back coat layer; and F5 stands for the F5 value in the longitudinal direction of the polyester film.