| abstract |
An unstretched cellulose acylate film which hardly breaks upon stretching can be produced by the melt film forming method, and thus a highly oriented stretched cellulose acylate film can be obtained. Using an extruder having a screw compression ratio of 2.5 to 4.5 and an L / D of 20 to 50, the cellulose acylate resin is extruded into a sheet shape from a die into a cooling drum at an extrusion temperature of 190 ° C to 240 ° C, cooled and solidified to be unstretched. After the cellulose acylate film 16 is produced, the cellulose acylate film is stretched to produce a stretched cellulose acylate film. |