Base films with advanced properties for magnetic recording media

Polyester film is today´s most important substrate for all kinds of magnetic tapes. In the course of the development from the first audio tapes to high quality video and computer tapes the demands on the carrier film have been constantly increased. Without loss in runnability of the film during tape manufacturing and in the recorder, substrates have become thinner and smoother. This paper gives an insight into the characteristics of polyester films for audio, video and computer application. The main parameters describing both the mechanical and the surface properties and their correlations to the attributes of magnetic tapes are discussed. In addition a survey of the usual manufacturing methods and optimization processes of the film surface for magnetic tape applications is presented.