| 摘要 |
PROBLEM TO BE SOLVED: To provide a retardation film made of a thermoplastic resin having less scratches and less variance in the optical axis or retardation. SOLUTION: A method for producing a retardation film comprises a step of blowing hot air ejected from a slit 20a in each nozzle 20 against a thermoplastic resin film F to heat and float and rendering the rotation speeds of nip rolls 30A, 30B, 32A, 32B, different from each other to longitudinally stretch the thermoplastic resin film F. The slit 20a in each of the nozzles 20 extends towards the widthwise direction of the thermoplastic resin film F. For each nozzle, Q is 3×10<SP>-2</SP>to 1×10<SP>-1</SP>m<SP>2</SP>/sec, wherein Q represents the sum total of Cs for all the slits provided in one nozzle, and C (m<SP>2</SP>/sec) represents a product of the speed A (m/sec) of hot air ejected from the slit and the width B (m) of the slit. The speed A of the hot air ejected from each of the slits is 2 to 15 m/sec. COPYRIGHT: (C)2009,JPO&INPIT |
