Chemical Reactions via Twin Screw Extrusion

Reactive extrusion describes a special process in extrusion technology in which individual components are bonded by a chemical reaction. Extrusion systems from Coperion are particularly suitable for the reactive extrusion process due to the excellent product handling and mixing properties.

To produce TPU (thermoplasic polyurethane) in the extruder the liquid raw materials are fed into the ZSK twin screw extruder infeed in the stoichiometric ratio via highly accurate liquid feeders. The reaction to polyurethane takes place in the twin screw extruder under constant mixing and kneading. Surplus reaction heat is dissipated through the barrel wall.

Discharge takes place via a gear pump and a screen pack changer directly to an underwater pelletizer. The pellets mature into a ready to sell product in the downstream drying plants, mixing or storage silos.

Various other reaction processes like polycondesation, polyaddition, e.g. are possible.

Typical end products

  • Technical components such as rollers, gears, drive belts, screens
  • Housings for electrical appliances
  • Components for the automotive industry such as wing mirror housings, bellows, decorative strips and panels
  • Sport shoe soles
  • Ice hockey skates and ski boots
  • Cable sheaths
  • Tubes and foils, also for medical technology
  • Artificial leather

Typical plant set-up for reactive extrusion shown by the example of linear thermoplastic polyurethane TPUs

Comprehensive product range


Due to its maximum flexibility in machine modifications the ZSK twin screw extruder of Coperion is the optimum system for reactive extrusion processes. With our comprehensive engineering know-how we design the ZSK extruder exactly to meet the requirements of your process.


With our comprehensive range of services Coperion and Coperion K-Tron are able to ensure maximum productivity and operational reliability of your compounding lines.