Highly intensive cooling process and apparatus for the production of

Abstract

An apparatus for highly intensive cooling of biaxially oriented films from high- and medium-molecular weight thermoplastics using a long neck on a blown film line is described, including: a plastics extruder, a die for forming a tube neck from the extruded plastic, means positioned adjacent the die for externally cooling the tube neck, an expansion zone where the tube neck becomes a bubble, a drag mandrel positioned immediately before the expansion zone for internally contacting, stabilizing and guiding the tube neck, means for continuously providing cool air internally of the tube neck at the expansion zone immediately after the contact, the means including a first tube in communication with a cool air source, and means for continuously removing the cool air that has been heated. A related method includes the steps of: extruding plastic material through a die to form a tube neck, externally cooling the tube neck immediately after emergence of the tube neck from the die, internally contacting, stabilizing, and guiding the tube neck into a bubble, immediately before the expansion zone, by using a drag mandrel, continuously internally cooling the bubble in the expansion zone immediately after the tube neck contacts the drag mandrel, and continuously removing the cool air that has been heated by the thermoplastic.