| 摘要 |
PURPOSE:To obtain a polyester film available for manufacturing a magnetic recording medium having excellent travelling and electromagnetic conversion characteristics, particularly a metallic thin-film magnetic recording medium by displaying the surface roughness of a second thin-film by a specific value by center-line mean roughness. CONSTITUTION:The film is composed of polyester manufactured while using an organic titanium compound as a polymerization catalyst, and a biaxially oriented film, both surfaces of which are coated with continuous thin-films, is employed as the film, and a first thin-film, in which a magnetic recording layer is formed onto the film, consists of at least one kind of a resin selected from an acrylic resin, a polyester resin and an acrylic-polyester resin and a composition mainly comprising a roughening substance having means grain size of 0.1mum or less. Projections resulting from the roughening substance are formed at the rate of 0.1X10<4>-1.0X10<9> number/mm<2> on the surface of the thin- film, and the surface roughness is displayed by 0.001-0.005mum by center-line mean roughness. The surface roughness of a second thin-film forming an easily smooth surface is expressed by 0.002-0.01mum by center-line mean roughness. |
