MANUFACTURING METHOD FOR CYLINDRICAL FILM

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a wide and long thermoplastic resin film, which has excellent economical efficiency and has no apparent defects such as a wrinkle, a sag and a scratch, by using a relatively small-sized device. SOLUTION: This method is characterized as follows: after being mixed and melted by a heating extruder, a thermoplastic resin is introduced into a mold with a circumferential mouthpiece; the molten resin, which is cylindrically extruded by a fixed tensile force, is received in a fixed thickness and cooled for solidification; and after that, the solidified resin is cut off in a state in which a cylindrical shape is maintained. Desirably, the size (d) of a circumferential mouthpiece gap and the thickness (t) of the film satisfy the relationship: t