CPVC is a outcome chlorinating CPVC, PVC resin is a main material for producing CPVC and this PVC resin must have loose type while not close type. CPVC is produced by aqueous phase suspension method, during the procedure the speed of diffusing chlorine have a influence upon speed of chlorinating PVC . So PVC resin which can be processed to CPVC should be required on which its skin is as thin as possible but its surface area is small. Therefore, this sort of PVC resin must be conpounded by a special suspension agent.

When CPVC resin is processed, a melt viscosity is two times as high as PVC's and a fusion temperature is higher than PVC. It is evident that to process CPVC is harder than PVC, especially in injection. Therefore, it is reasonable to use PVC resin which have lower degree of polymerization to compound CPVC resin. Normally PVC resin of P=700 can be used for extrusion and P=500 for injection.

CPVC resin's properties result the properties of processing. Generally Chiorine content of PVC is 56～59%, and CPVC is 64～75%, as the increase of chlorine content in CPVC, the melt viscosity, temperature resistance, density and tensile strength can be increased but also the brittleness is increased, impact strength is decreased and processing difficulty is increased.

CPVC products and processing properties depend on their resin's properties. Hopefully if Chlorine content of CPVC resin is higher than 70% the surface chlorine content should be lower ,and that would result to be easy for processing CPVC.