| 摘要 |
A thermoplastic resin film and a preparation method thereof are provided to produce optical films having uniform optical characteristics by preventing streak defects or inhibiting retardation. A method for preparing a thermoplastic resin film includes the steps of: extruding a molten thermoplastic resin from a die in a sheet form; interposing the thermoplastic resin sheet between a cooling roller(27) for pressurization and a pressurizing roller(26) having a surface roughness average height(Ra) of 100 nm or less to cool and solidify the thermoplastic resin sheet; and cooling and solidifying the thermoplastic resin sheet while carrying the thermoplastic resin sheet by many cooling rollers(28,29). The temperature of every cooling roller is in the range of ±3 °C relative to sheet temperature when the thermoplastic resin sheet gets in contact with the cooling roller. When the thermoplastic resin sheet is separated from the most downstream cooling roller of the many cooling rollers, the sheet temperature is equal to or less than a glass transition temperature(Tg, °C) of the thermoplastic resin-15 °C. |
