PVC compounds are extruded in single as well as in twin screw extruders.
Whereas co-rotating twin screws are mainly used for compounding operations, counter rotating screws are used for the extrusion of profiles, pipes, panels, pellets, tubes and rods. Twin screws are divided in parallel and conical configurations.
PVC is of low thermal stability and high melt viscosity. Therefore, it is combined with a number of additives to vary properties to suit different end-use applications. PVC formulation is key to processing success.