| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a thick thermoplastic resin film with biaxial orientation, whose crack generation in a film surface is inhibited in a longitudinal stretch step.SOLUTION: A non-stretched thermoplastic resin sheet 11 with a glass transition temperature of Tg(°C) is made to a film 13A of 500 μm or more and 2,000 μm or less in thickness, by stretching in conveying direction between a heating roll and a first cooling roll while conveying from a heating roll 24 to a first cooling roll 26. Average temperature in a thickness direction of the film after stretching in the conveying direction is reduced to (Tg-5)°C or lower before the film contacts the second cooling roll by quenching it with a cooling speed of 30°C/s or more and 100°C/s or less in a section immediately after contacting the first cooling roll and before contacting a second cooling roll while conveying it from the first cooling roll 26 to a second cooling roll 28. The film after passing the second cooling roll is stretched in a width direction. |
