FORMATION OF MULTI-LAYERED INFLATION FILM

摘要

PURPOSE:To obtain a multi-layered inflation film havng a high strength and a high uniformity with lesser directivity by a method in which a simple device is provided at the lower end part of a molten resin cylinder molded of a resin having a great frictional resistance when melted for its inner layer and a high- density polyester resin for its outer layer. CONSTITUTION:A resin (e.g., low-density polyethylene resin, etc.) having a great frictional resistance when melted for an inner layer and a highdensity polyethylene resin for an outer layer are extruded from the annular slit 3 of an annular die to form a molten resin cylinder 4. The molten resin cylinder 4 is then expanded and cooled from outside by airing to the outside of the annular die 2 to form a multi-layered inflation film. In this case, an air sucker 7 is provided to the lower end of the molten resin cylinder 4, and air is passed through the opening 8 for airing 5 and a rectifying cylinder 9 provided around the resin cylinder 4 for cooling the cylinder to obtain a desired molding.