INTENSITY CHANGED POLYESTER FILM WITH UNIAXIAL STRETCHING CONDITION AND THE PRODUCING METHOD THEREOF

摘要

The present invention relates to an intensity changed polyester film with uniaxial stretch and a method for producing the same. The method for producing the intensity changed polyester film with uniaxial stretch is a method for producing the polyester film using a method for changing patterns when uniaxial stretching the polyester film. The method enhances mechanical strength by a single-stage orientation at higher than glass transition temperature of the polyester film by supplying heat by a radiation heater during MD orientation which is the uniaxial stretch of the polyester, and an additional second stage orientation before cooling process. The single-stage and second stage orientation during the MD orientation satisfy math formula (1): 0.5<= ( MD1/MD2) <=3.0 -----math formula (1). Here, MD1 indicates the single-stage orientation, and MD2 indicates second stage orientation. The intensity changed polyester film with uniaxial stretch and a film obtained thereby have enhanced thermal stability during high temperature fabrication by changing orientation patterns of the polyester in order to improve heat resistance, and solve conventional problems by providing the polyester film with enhanced dimensional stability while processing near the glass transition temperature of the polyester film.