PROCESS FOR PRODUCING PHASE DIFFERENCE FILM OF THERMOPLASTIC RESIN

摘要

This invention provides a process for producing a phase difference film of a thermoplastic resin. The production process comprises the step of blowing hot air ejected from a slit (20a) in each nozzle (20) against a thermoplastic resin film (F) within an oven comprising nozzle arrays disposed opposite to each other in a staggered nozzle arrangement to heat and float the thermoplastic resin film (F) 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 not less than 3 x 10m/sec and not more than 1 x 10m/sec wherein Q represents the sum total of Cs for all the slits provided in one nozzle. C represents a product of the speed (m/sec) of hot air ejected from the slit and the width (m) of the slit, m/sec. The speed of the hot air ejected from each of the slits is not less than 2 m/sec and not more than 15 m/sec.