Cooling extruded thermoplastic film - by immersing in cooling bath and introducing liquid cooling agent inside film

摘要

Thermoplastic film esp. a low density polyethylene film is produced by (a) extruding the film downwards, (b) introducing the extruded film into a cooling bath placed below the extrusion head and (c) introducing into the interior of the extruded film a liquid cooling agent, esp. water, supplied by means of the extrusion head, in such a manner that the agent contacts the interior wall of the film. The film is used for prodn. of bags and packages. Thick films can be cooled rapidly, thus considerably increasing the rate of prodn. Deformation of the film is avoided. The film has a practically amorphous structure and good impact resistance and optical properties.