Chlorinated Polyvinyl Chloride

Two processes are used to manufacture chlorinated polyvinyl chloride (PVC). In one process, PVC is chlorinated in a dry particulate state by means of a fluidized bed under ultraviolet irradiation. The other process involves a wet chlorination, under irradiation, of an aqueous suspension of solid PVC plus a small amount of chloroform to promote swelling of the PVC. Both processes produce a chlorinated resin of about 66-69 wt% chlorine from a feed resin of 56.7 wt% chlorine. The product polymer has an increased softening point which makes it particularly suitable for hot water pipe applications.