METHOD OF AND APPARATUS FOR MANUFACTURING TUBULAR THERMOPLASTIC RESIN FILM HAVING A ROUGH INNER SURFACE

摘要

In a method of and an apparatus for manufacturing a tubular thermoplastic resin film having a rough inner surface, the temperature of a mandrel (11) located near a discharge port (16) of a resin passage (13) is set lower than the temperature of a die ring over a limited range in the circumferential direction of the discharge port. A cooling device provided in the mandrel (11) for cooling the portion of the mandrel located near the discharge port (16) of the resin passage to a temperature lower than the temperature of the portion of the die ring located near the discharge port (16) is therefore provided over a limited range in the circumferential of the discharge port of the resin passage.