Polyester film for magnetic recording media, process for preparation thereof and magnetic recording medium

摘要

A polyester film for magnetic recording media, a process for preparation thereof and a magnetic recording medium comprising the film having formed on the surface of a ferromagnetic metallic thin membrane, said polyester film being one wherein on the surface of one side or both sides of the film, (i) fine protuberances having an average height of 0.15 mu m or less exist at a rate of 1.0x104 to 1.0x108 per mm2, (ii) the fine protuberances are composed of fine particles whose surface is coated with a binder resin, (iii) the fine protuberances are stuck on the film surface by the binder resin, (iv) the binder resin does not substantially exist on the film surface other than in the vicinity of the film surface where the fine protuberances exist, and (v) the average surface roughness (Ra) of the film surface is in the range of 0.001 to 0.01 mu m.