POLYESTER FILM FOR MAGNETIC TAPE

摘要

PURPOSE:To obtain a base film for a magnetic tape having excellent smoothness and wear resistance by incorporating CaCO3 powders having specific average grain sizes respectively in different ranges into polyester consisting essentially of ethylene terephthalate. CONSTITUTION:A biaxially stretched film is manufactured by dispersing 0.01- 1.0wt% CaCO3 powder having 0.01-0.39mu average grain size and 0.05-0.2wt% CaCO3 powder having 0.40-1.0mu average grain size into polyester of which the main repeated unit consists of ethylene terephthalate. This film has good surface smoothness and wear resistance and the excellent film for a magnetic tape is obtd.