SYNDIOTACTIC POLYSTYRENIC BIAXIALLY STRETCHED FILM

摘要

PURPOSE:To obtain a polystyrenic biaxially stretched film excellent in slitting properties substantially formed from a styrenic polymer having a syndiotactic structure, characterized by that an orientation ratio calculated according to a predetermined formula is 1.6 or more and having specific distribution in the azimuth angle direction of a specific crystallite in wide angle X-ray diffraction. CONSTITUTION:A syndiotactic polystyrenic biaxially stretched film is substantially formed from a styrenic polymer having a syndiotactic structure and the orientation ratio calculated according to formula; orientation ratio = Ax/Ay (wherein Ax is 1222cm<-1> band intensity when the polarizing direction of infrared rays coincides with the lateral direction of the film and Ay is 1222cm<-1> band intensity when the polarizing direction of infrared rays coincides with the longitudinal direction of the film) of the film is 1.6 or more and the distribution in the azimuth angle direction of a crystallite evaluated using a crystal diffraction peak present at 20.6 deg. in wide angle X-ray diffraction is not divided in the vicinity of the max. value and has only one peak.