ZSK FilCo Filtration Compounder

In conventional recycling plants, PCR and contaminated polymers must first be melted using a single or twin screw extruder, then filtered and pelletized thereafter. For plastics upcycling purposes the filtered recompounds are then fed into a separate twin screw extruder where they are again melted and compounded with the aid of additives, reinforcing materials and fillers before finally being pelletized. In this production set-up, energy for melting must be introduced twice. Along with high energy consumption, the recyclate is subjected to high thermal stress which in turn results in increased degradation, shortening of polymer chains and thus a reduction in product quality.

The ZSK FilCo makes it possible to melt, filter, compound and pelletize recyclate in a single production system. Waste plastic is fed into the ZSK extruder in the form of regrind, fiber pellets, film flakes or agglomerate and is melted, homogenized, and devolatilized there, together with all its components (all polymers, PE, PP, PA, PS, PC/ABS, etc.). Next the melt is fed through an integrated filter that removes all contaminants. Reintroduction into the ZSK extruder process section follows, where reinforcing materials such as glass, wood, and carbon fibers, or fillers such as talc, CaCO₃ or ground PEX are added, after which the recompound is pelletized. 

The ZSK FilCo’s space requirement is comparatively low. All product streams are added gravimetrically to the process with no fluctuations. The recyclate needs to be melted only once. The ZSK FilCo thus consistently achieves a higher product quality than multi-part systems that have been typically used for this recycling process.

Moreover, energy consumption and emissions for the extrusion process are markedly reduced with the new solution. Thanks to the twin screw extruder’s high mechanical energy input, the melting process is more energy efficient than with a single screw extruder. In addition, the second melting process for compounding is completely eliminated in the ZSK FilCo solution and pelletizing of the intermediate compounds is also omitted.