In compounding, plastics are refined for later use by adding or blending additives. Compounding serves to specifically optimise the properties of the plastic, tailored to its later use.
The refinement of plastics is usually carried out with the aid of a twin screw extruder. This so-called twin-screw extruder conveys the polymer through two intermeshing, rotating screws to the extruder outlet or the next process stage. The material passes through different zones in the extruder, where it is melted and converted into a plastic moulding compound with the addition of additives. Talc, release agents, fibres, antioxidants and various other additives are used in the compounding process.
By adding the additives, physical, thermal, electrical or even aesthetic properties of the plastic are changed in the plastic compounding process.