BIAXIALLY ORIENTED SYNDIOTACTIC POLYSTYRENE FILM

摘要

PURPOSE:To obtain the title film which is excellent in heat resistance and has good handleability irrespective of the film thickness. CONSTITUTION:The film comprises a substantially syndiotactic styrene polymer and has an orientation ratio as will be defined hereinbelow of 0.2-1.5, a ratio of the heat shrinkage stress at 200 deg.C in the transverse and longitudinal directions to the dynamic modulus (10Hz) at 200 deg.C of 0.015 or lower, and a dynamic modulus (10 Hz) at 200 deg.C in the transverse and longitudinal directions of 1.0X10<6> dyne/cm<2> or higher. The orientation ratio is defined as Ax/Ay wherein Ax is a band strength at 1222cm<-1> when the direction of polarization of infrared rays is the same as the transverse direction of a film; and Ay is a band strength at 1222cm<-1> when the direction of polarization of infrared rays is the same as the longitudinal direction of a film.