TH26642A - The aqueous suspension polymerization process of vinyl chloride using dialkyl peroxydicarbonate in solution, and the process for producing dialkyl peroxydicarbonate solution. - Google Patents

Abstract

DC60 (12/07/56) A process for the aqueous suspension polymerization of vinyl chloride using dialkyl peroxydicarbonate as a solvent and a process for producing a solution of dialkyl peroxydicarbonate. Short-chain alkyl dialkyl peroxydicarbonate, preferably diethyl, is used for the aqueous suspension polymerization of vinyl chloride in solution form in a liquid and insoluble dialkyl alkane dicarboxylate. A popular solvent is hexane dicarboxylate (adipat) derived from adipic acid and from C6-C10 alkanol. The peroxydicarbonate concentration of the said solution is generally 15-40% by weight. The process described in this invention produces a vinyl chloride polymer with improved quality resulting in a lower pitch-eye. This invention also involves a two-step process for producing the solution. Short-chain alkyl dialkyl peroxydicarbonates are particularly suitable for the polymerization of vinyl chloride. In this process, inorganic salts are used in the peroxydicarbonate production step (step 1) and subsequently separated by extraction with an insoluble solvent (step 2). The process of aqueous suspension polymerization of vinyl chloride using dialkyl peroxydicarbonates for dissolution and the production of dialkyl peroxydicarbonate solutions are described. A popular short-chain alkyl dialkyl peroxydicarbonate is diethyl, which is used for aqueous suspension polymerization of vinyl chloride in the form of a solution in a liquid and insoluble dialkyl alkane dicarboxylate. A popular solution is hexane dicarboxylate (adipath). Adipic acid and C6-C10 alkanol are used to extract the peroxydicarbonate solution, typically at concentrations of 15-40% by weight. The process described in this invention produces a vinyl chloride polymer, a quality improvement resulting in a product exhibiting lower pitch. This invention also involves a two-step process for producing a short-chain alkyl dialkyl peroxydicarbonate solution, particularly suitable for the polymerization of vinyl chloride. Under this process, inorganic salts are introduced in the peroxydicarbonate production step (step 1) and subsequently separated by extraction with an insoluble solvent (step 2).

Claims (12)

1. The process for aqueous suspension polymerization of vinyl chloride using alkyl peroxydicarbonate with 2 or 3 carbon atoms. The dialkyl peroxydicarbonate is used in the form of a solution containing, essentially, dialkyl peroxydicarbonate and dialkyl alkane dicarboxylate, which are liquids and insoluble in water. The concentration of dialkyl peroxydicarbonate in the solution ranges from 15-40% by weight. 2. The process for the aqueous suspension polymerization of vinyl chloride according to Patent 1 is generally characterized by the selection of dialkyl alkane dicarboxylates from liquid esters derived from C4-C10 alkane dicarboxylic acids and from C2-C12 alkanols. 3. The process for the aqueous suspension polymerization of vinyl chloride according to claim 2 is generally characterized by the selection of dialkyl alkane dicarboxylate from hexanedicarboxylate (adipate) derived from adipic acid and C6-C10 alkanol. 4. The process for the aqueous suspension polymerization of vinyl chloride, as per claim 1, is generally characterized by a dialkyl peroxydicarbonate concentration in the solution of approximately 15-40% by weight. 5. The process for the aqueous suspension polymerization of vinyl chloride according to claims 1 through 4 is generally characterized by the use of diethyl or diisopropyl peroxydicarbonate in solution form in hexane dicarboxylate (adipath) derived from adipic acid and from C6-C10 alkanol. 6. The process for the aqueous suspension polymerization of vinyl chloride according to claims 1-5 is characterized by the fact that polymerization is initiated without the use of short-chain alkyl dialkyl peroxydicarbonates. 7. The process for producing short-chain alkyl dialkyl peroxydicarbonate solutions generally involves the following steps: First, the short-chain alkyl dialkyl peroxydicarbonate is produced by reacting it in water containing a suitable amount of alkyl aloformate and inorganic peroxide, along with sufficient inorganic salts to increase the density of the aqueous mixture. Second, the produced dialkyl peroxydicarbonate is then dissolved by extraction using the mean of the aqueous solution to produce a dialkyl peroxydicarbonate solution. 8. The process for producing short-chain alkyl peroxydicarbonate dialkyl solutions according to claim 7 is generally characterized by the use of sufficient quantities of inorganic salts to bring the density of the aqueous reaction medium to a minimum of 1.05. 9. The process for producing short-chain alkyl dialkyl peroxydicarbonate solutions according to claims 7 and 8 is generally characterized by the use of the inorganic salt sodium chloride. 10. The process for producing short-chain alkyl dialkyl peroxydicarbonate solutions under claim 7 is generally characterized by the selection of an insoluble solvent from the usual plasticizing agent for polyvinyl chloride. 11. The process for producing short-chain alkyl peroxydicarbonate dialkyl solutions under claim 10 is generally characterized by the selection of an insoluble solvent from dialkyl alkane dicarboxylates derived from C4-C8 alkane dicarboxylic acids and from C6-C10 alkanols. 12. The process for producing short-chain alkyl dialkyd peroxydicarbonate solutions according to Patent 11 is characterized by the selection of an insoluble solvent from hexanedicarboxylate (adipate) derived from adipic acid and from C6-C10 alkanols (Petition 12, 2 pages, 0 figures).