PROCESS FOR THE SUSPENSION POLYMERISATION OF VINYL CHLORIDE

摘要

The peroxydicarbonates of dialkyl with short alkyl chains, preferably of diethyl and diisopropyl, are implemented for the polymerisation in aqueous suspension of vinyl chloride in the form of a solution in a water insoluble liquid dialkyl alkanedicarboxylate. The preferred solvents are hexanedicarboxylates (adipates) derived from adipic acid in C6-C10 alcanols. The concentration of peroxydicarbonate in said solutions is generally 15-40 % by weight. The process of the invention produces vinyl chloride polymers having an improved quality to fabricate shaped articles having substantally less fish-eyes. The invention also relates to a process for producing in two phases a solution of dialkyl peroxydicarbonates with short alkyl chains particularly appropriate for the aqueous suspension polymerisation of vinyl chloride. According to said process, an inorganic salt is implemented in the step of production of peroxydicarbonate (first step) and the latter is then separated by extraction by means of a water insoluble solvent (second step).