| 摘要 |
A dope is prepared from TAC, mixed solvent and additive. The dope is cast from a casting die ( 31 ) onto a belt ( 34 ). A casting film ( 69 ) is formed on the belt ( 34 ). The casting film ( 69 ) is carried in association with movement of the belt 34. A rapid-drying blower unit ( 73 ) is disposed at a position, which is separated from a labyrinth seal ( 50 ) by 1000 mm in a downstream direction. Dry air ( 57 ) is applied to the casting film from a nozzle ( 73 a) of the blower unit ( 73 ). Velocity of the dry air ( 57 ) is adjusted to 12 m/s. An initial film ( 69 a) is formed on the casting film ( 69 ). The entire casting film ( 69 ) is dried after forming the initial film ( 69 a). The casting film ( 69 ) is peeled from the belt ( 34 ) after having a self-supporting property. The casting film is heated and stretched in a tenter drier and is dried in a drying chamber.
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