A POLYESTER FILM FOR LEADER TAPES, AND A PRODUCTION PROCESS THEREOF

摘要

A polyester film that can provide a leader tape wherein the surface unevenne sses of the etched part are minute and uniform and which is excellent in appearance, does not cause magnetic ta pe troubles, and has a high commodity value; and a process for producing a polyester film that can provide a leade r tape having an arbitrary thickness distribution pattern with a good reproducibility, that can provide a leader tape wherein the surface unevennesses of the etched part are minute and uniform and which has an excellent appearance and a high commodity value, and that can further provide a leader tape having various thicknesses at a reduced produc tion cost because it enables a number of working runs at once. This film is produced by contacting a polyester film w ith an alkaline liquid to etch at least one side of the film to give rise to thickness distribution. The production proc ess is characterized by suitably controlling the extent of etching site by site to realize any arbitrary thickness distri bution. Preferably the etching is conducted by immersing the film in an alkaline liquid.