| 摘要 |
PURPOSE:To provide the title film having a surface roughness within a specified range and excellent traveling properties and suitable for use as a magnetic tape, etc., by incorporating specified amounts of a polyoxyalkylene glycol component and a higher fatty acid compd. in a polyester and molding the mixture into a film. CONSTITUTION:In the production of a polyester by polycondensing a dicarboxylic acid with a diol, 0.01-10wt% polyoxyalkylene glycol (e.g., polyethylene glycol) and 0.005-2wt% compd. mainly composed of a 10-50C higher aliph. monocarboxylic acid (e.g., stearic acid), its ester or its metal salt are added to the reaction system, each amount being based on that of the polyester. The resulting polyester is molded into a film, thus obtaining the desired polyester film having a surface roughness Ra of 0.004-0.09mum. In this way, the bleedout of the higher fatty acid compd. toward the surface of the film can be inhibited. |
