Symbol: PP
Crystallinity: Crystalline
Trade Names: Edgetek, EnCom, RTP, FERRO

Polypropylene:Advanced Guide (by permission of SpecialChem)
Learn more about Polypropylene


PP Ketchup Fotolia_41650198_S.jpgPP has a low density and has good resistance to chemicals and fatigue. It is available in several formulations. The more crystalline HOMOPOLYMER is stiff and has good tensile strength. HIGH IMPACT COPOLYMERS are somewhat less crystalline and are used more for film and blow molding.

Processing Considerations:

  • Residence Time: Residence time is 1.5 minutes or greater.
  • Back Pressure: Keep back pressure at 250 PSI (or 2500 plastic pressure) or less.
  • Drying: Drying is not required.
  • RPM: RPM is 30 or greater.

Screw Design Based on:

  • High Compression Ratio
  • Medium Transition Length
  • Shallow Meter Channel Depth

Other Information:

  • Mixer: A high performance mixing screw can improve results when running PP. Reiloy Westland Corporation’s Eagle mixer has been proven to successfully process this resin.
  • Barrier: Barrier screws are recommended.
  • Custom Design: A custom screw designed for PP featuring a barrier or barrier mixer is recommended.
  • Recommended Valve: A three piece free-flow valve, three piece locking valve, four piece valve or ball check can be used.
  • Screw & Barrel Material Recommendation: Screws and barrels can be manufactured out of standard materials unless filled resin is being processed.
  • Similar to Resin: The process is similar to PE.

Various additives and/or fillers can have an effect on a resin’s process behavior. For more detailed information, please contact Reiloy Westland Corporation.

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Industry Applications - Resins

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