Abstract
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 decom pression screw and cooled grooved feed throat is typically used to process molten polymer at high rates. An internal bubble cooling (IBC) system and in ternal bubble stabilizer (IBS) overcome destabilizing effects and control the gauge at high outputs. Post-die orientation is induced via a high stalk con figuration 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 describes how film performance can be altered using fabrication laboratory equipment to simulate the film making process of the bag making industry.
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