There are suspension polymerization method, emulsion polymerization method and bulk polymerization method, with suspension polymerization as the main, about 80% of total PVC production.
(1) Suspension polymerization allows the monomer to be dispersed in a micro-droplet suspension in the aqueous phase, the selected oil-soluble initiator is dissolved in the monomer, the polymerization reaction is carried out in these droplets, the polymerization reaction heat is absorbed by water in time, in order to ensure that these droplets in the water bead-like dispersion, need to add suspension stabilizer, such as gelatin, polyvinyl alcohol, methyl cellulose, Hydroxyethyl cellulose and so on. The initiator uses organic peroxide and azo compounds, such as peroxide dimethyl carbonate peroxide two cyclohexyl carbonate, dimethyl carbonate and Azo-N-nitrile, azo-nitrogen, and other two-different. Polymerization is carried out in a polymerization kettle with a blender. After polymerization, the material flows into the monomer recovery tank or the recovery monomer in the stripper. Then flow into the mixing kettle, washed and then centrifugal dehydration, drying of resin finished products.
(2) Emulsion polymerization method of the earliest industrial production of PVC. In emulsion polymerization, besides water and vinyl chloride monomer, we should add surfactants such as alkyl sulfonic acid sodium as emulsifier, so that monomer dispersed in water phase into milk liquid, with water-soluble potassium sulfate or ammonium persulfate as initiator.