Devolatilization of recycled material
Thanks to its excellent devolatilization properties, Coperion's twin screw extrusion systems are ideally designed for the "bottle to fiber" process in which used PET bottles are recycled and turned directly into fibers.
PET bottle flakes, new PET product and masterbatch are fed into the Coperion ZSK extruder via highly accurate Coperion K-Tron gravimetric feeders.
Processing shredded PET bottles with a single screw extruder requires a complex laborious drying process. By contrast, Coperion's ZSK twin screw extruder can process the PET while being essentially non-dried, and devolatilize the melt with a low energy expenditure in a vacuum of 1-5 mbar (absolute). Volatile contaminations and oligomers are extracted from the melt and separated from the exhaust gas flow in suitable separators upstream of the vacuum pump.