METHOD FOR PRODUCING OPTICAL FILM, OPTICAL FILM, POLARIZING PLATE, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

Disclosed is a method for producing an optical film by a solution casting film forming process wherein a resin solution that contains an acrylic resin and a cellulose ester resin at a mass ratio from 95:5 to 30:70 is used as a dope, said method comprising: a first stretching step wherein a film separated from a supporting body is MD stretched; a second stretching step wherein the film stretched in the first stretching step is TD stretched; a cutting step wherein both end portions of the film stretched in the second stretching step are cut off; and a third stretching step wherein the film, from which the cut end portions have been removed, is MD stretched. If the content of the acrylic resin is represented by A mass%, the total of the drawing ratio in the first stretching step and the drawing ratio in the third stretching step is from A/3 + 10 to A/5 + 40 in percentage. The drawing ratio in the first stretching step is 70-95% of the total drawing ratio in the machine direction of the film.