Method of producing biaxially oriented tubular polyetheretherketone films

摘要

A method of producing biaxially oriented tubular polyetheretherketone films having good optical and mechanical properties and heat resistance, by rapidly quenching at a rate of at least 24 DEG C. per second an unoriented tubular polyetheretherketone film as melt-extruded through a circular die thereby imparting a crystallinity of not greater than 10% to the film, and continuously introducing the thus produced film into the space between a feed nip roll pair and a pull nip roll pair while reheating the film externally to a temperature of 60 DEG -140 DEG C. and allowing the film to expand under the influence of the internal pressure to an areal draw ratio of 4-36, to thereby attain biaxial orientation.