When dealing with a reaction system with high viscosity, twin screw extruder has overwhelming advantages due to its great heat and mass transfer performance, excellent interface renewing ability, narrow residence time distribution, large specific surface for devolatilization, and low threshold for continuous operation. Twin screw polymerization extruder, or twin screw reactor, can be used for not only the heat transfer, mixing, shearing, conveying, venting and extrusion, but also polymerization reactions. So the processing techniques are more complicated and more technologies are involved. This kind of extruder is not frequently used but is of great importance. Different reaction types have different requirements for the extruder’s structure and parameters. Custom machine is usually needed for specific material system and polymerization technique.
TPU reactive extrusion (polyurethane fiber, elastomer and adhesive), PC melt phase polycondensation, PMMA bulk polymerization, acrylic resin polymerization, nylon polycondensation and different kinds of grafting reaction.
Flow Chart for TPU Reactive Extrusion Lines
1. metering feeder system 2. material silo 3. mixing head 4. twin-screw extruder 5. diverter valve 6. screen changer 7. underwater pelletizer 8.centrifugal dewatering 9. vibrating sleve 10. product container