Processing aids are an important class of additives for poly(vinyl chloride) (PVC).
At relatively low concentration, processing aids enable the melt processing of rigid PVC and enlarge its processing windows.
Discussed in this presentation are some major functions of processing aids, such as promoting PVC fusion, modifying PVC’s melt rheology, and lubricating to prevent adherence of PVC melt to the processing equipment.
Some examples are given to show the effects of processing aids on PVC die swell, melt fracture, melt viscosity, and PVC fusion. Commercial sources of various processing aids and typical PVC formulations for various applications are also discussed.