| 摘要 |
It is an object to provide a method of manufacturing a thermoplastic film capable of improving optical properties of the thermoplastic film obtained by drawing it and to provide the thermoplastic film. In a transverse drawing process part 30 for drawing a thermoplastic film 16 in a transverse direction is constituted by a preheating zone T 1 and transverse drawing zones T 2 , T 3 and cooling zones T 4 , T 5 , and the steps of the transverse drawing zone T 3 and performed thereafter (cooling zone T 4 and T 5 ) are maintained at a glass transition temperature Tg or less. The temperature of the preheating zone T 1 is set to be higher than that of the cooling zone T 4 and falls within the range of -10 C to +30 C relative to those of the transverse drawing zones T 2 and T 3.
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