Polyamide-imide
| Symbol: | PAI |
| Crystallinity: | Amorphous |
| Trade Names: | Torlon |
Description:
PAI is an amorphous, high temperature, engineering resin. It has superior mechanical properties up to 500°F with good dimensional stability, impact and chemical resistance. It is very viscous and hydraulic accumulators are often used for fast fill. Two grades are available, Standard and #2000 all by Amoco. They have quite different screw designs and processing parameters.
Processing Considerations:
- Residence Time: Residence time is between 2 and 4 minutes. Excessive residence time increases the resistance to flow (viscosity). Parts are post-cured to achieve properties.
- Back Pressure: Use low back pressure.
- Drying: PAI material must be dried.
- RPM: RPM will run 30 or greater.
Screw Design Based on:
- Low Compression Ratio
- Long Transition Length
- Deep Meter Channel Depth
Other Information:
- Mixer: A low shear mixer, like Reiloy Westland Corporation’s Eagle mixer, can be used in processing PAI.
- Barrier: A barrier screw is not recommended when processing PAI.
- Custom Design: A custom screw designed to process PAI will produce better results than a general purpose screw.
- Recommended Valve: It is recommended to have a flighted smear tip incorporated onto the screw.
- Screw & Barrel Material Recommendation: The screw and barrel processing PAI should be manufactured from special alloys.
Various additives and/or fillers can have an effect on a resin’s process behavior. For more detailed information, please contact Reiloy Westland Corporation.