To reduce film thickness nonuniformity, the rise of retardation Rth in the thickness direction, and Rth nonuniformity.
In a method for producing a thermoplastic film in which a molten resin 90 from a die 20 is pushed by a first casting roll 28 and a touch roll 24 and extrusion-molded, the molten resin 90 immediately after being extrusion-molded by the first casting roll 28 and the touch roll 24 is heated. Concretely, in the conveyance process of the molten resin 90 extrusion-molded by the first casting roll 28 and the touch roll 24, a heat source 92 having directivity is installed at a position slightly separated from the gripping part between the first casting roll 28 and the touch roll 24. For example, an infrared heater, a halogen heater, an electric heater, or the like can be used as the heat source 92.
Toshiyuki Miyadera
Naoki Kashima
Yasuo Takubo