METHOD FOR COOLING CRYSTALLINE THERMOPLASTIC RESIN FILM

摘要

PROBLEM TO BE SOLVED: To provide a film cooling method for obtaining a crystalline thermoplastic resin film extremely excellent in transparency. SOLUTION: The crystalline thermoplastic resin film 3 extruded in a molten state from a T-die is guided to the surface of a rotary cylindrical cooling roll 4 and, subsequently, the film 3 extruded in a molten state with the rotation of the cylindrical cooling roll is directly cooled to a temperature lower than the softening temperature of the crystalline thermoplastic resin on the cylindrical cooling roll by cooling water supplied to and present in the cooling water channel 57 formed by the cylindrical cooling roll and a water cooling drum 5 having a recessed part corresponding to the cylindrical part of which the area is almost 1/4-1/2 the area of the cylindrical outer peripheral surface of the cylindrical cooling roll.