Process for producing a biaxially oriented polyester film and biaxially oriented polyester film

摘要

The present invention is directed to a process for producing a biaxially oriented polyester film which comprises: subjecting a polyester film to simultaneous biaxial stretching in a stretching apparatus constructed to simultaneously stretch the film in the lengthwise and widthwise directions thereof: and subsequently subjecting the film to successive biaxial stretching in the lengthwise and widthwise directions thereof in the same apparatus as mentioned above. With this process, a film can be efficiently formed, without film breaking, which film is small in thickness and greatly strong in its lengthwise and widthwise directions.