PURPOSE: To manufacture a high-quality polyester film superior in uniformity in thickness at a high speed, by a method wherein a mixture obtained by mixing polyalkylene glycol and/or its deviation with a polyester composition containing an alkaline metallic salt derivative of sulfonic acid is melted and extruded in a filmy state and then the film is stuck to a rotary cooling roll in an electro static state for quenching and solidification.
CONSTITUTION: A polyester composition containing a 0.0003W0.1wt% alkaline metallic salt derivative of sulfonic acid as a metallic atom and 0.1W10wt% polyalkylene glycol and/or its derivative to polyester are mixed up with each other. The mixture is melted and extruded in a filmy state and then the melted and extruded film is quenched and solidified by sticking the film to a rotary cooling roll in an electrostatic state. Loading of the alkaline metallic salt derivative of sulfonic acid and the polyalkylene glycol and/or its derivative are effective for an improvement in electrostatic adhesion. It is preferable that the obtained film is stretched unidirectionally at least 1.1 times or longer which is desirably 2.5 times or longer from the viewpoint of provision of the film for various uses by improving dynamic properties and the other physical properties.
HAMANO AKITO
MAKIMURA OSAMU
