METHOD OF PRODUCING BIAXIALLY ORIENTED POLYETHER ETHER KETONE FILM.

摘要

A biaxially oriented film of a polyether ether ketone (PEEK) having excellent accuracy, insulating properties and thermal shrinkage resistance is easily obtained from a noncrystalline PEEK film by roll stretching the film 1.5- to 3.5-fold in the machine direction while causing the necking of the film in the temperature range from 50 DEG C to Tg minus 10 DEG C, stretching the monoaxially stretched film 1.5- to 3.5-fold in the direction perpendicular to that of the first stretching in the temperature range from Tg to 170 DEG C, and heat setting the film thus stretched in two stages in the temperature ranges from 210 to 330 DEG and from 180 to 210 DEG C.