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