Quality Performance Optimization Tools for the Fabrication of HMW-HDPE Blown Film, 1990 Polymers, Laminations & Coatings Conference Proceedings

Film used in the merchandise bag and grocery sack markets is often made of High Molecular Weight High Density Polyethylene (HMW-HDPE) resin. It allows blown film to be fabricated at relatively thin gauges while maintaining required strength properties. An extruder with a decompression screw and cooled grooved feed throat is typically used to process molten polymer at high rates. An internal bubble cooling (IBC) and internal bubble stabilizer (IBS) overcome destabilizing effects and control the gauge at high inputs. Post-die orientation is induced via a high stalk configuration to obtain the desired performance properties. This paper deals with the control aspects of extrusion and orientation to obtain a uniform gauge and a good distribution of the properties. It is demonstrated how performance can be altered during fabrication. A description is provided of the laboratory equipment used to simulate the film making process for the bag making industry.