COOLING THERMOPLASTIC TUBES

摘要

Cooling an extruding thermoplastic tube by feeding the tube adjacent a cooling surface, maintaining a sheath of heat-transfer fluid between the tube and surface and preferentially cooling at least a selected area of the tube by transversely displacing the tube to decrease the thickness of the sheath between the selected area and the cooling surface. The invention is particularly suitable, for the production of thermoplastic films by orienting a cast tubular extrudate which has been cooled by means of an internal mandrel.