Polyvinyl chloride , abbreviated as PVC, is a polymer polymer formed by vinyl chloride monomer (VCM) in peroxides, azo compounds and other initiators, or polymerized according to the polymerization reaction mechanism of free radicals under the action of light and heat, with excellent properties such as heat resistance, wear resistance, corrosion resistance, fire retardancy, insulation, easy availability of raw materials and low price. Together with polyethylene (PE), polypropylene (PP), polystyrene (PS) and ABS, it is collectively referred to as the five general resins.

According to the different application range, PVC can be divided into: general-purpose PVC resin, high polymerization PVC resin, crosslinked PVC resin. General-purpose PVC resin is formed by polymerization of vinyl chloride monomer under the action of initiator; High polymerization degree PVC resin refers to the resin polymerized by adding chain growth agent to the polymerization system of vinyl chloride monomer; Crosslinked PVC resin is a resin polymerized by adding a crosslinking agent containing dienes and polyenes to the polymerization system of vinyl chloride monomer.

According to the method of obtaining vinyl chloride monomers, polyvinyl chloride can be divided into calcium carbide method, ethylene method and imported (EDC, VCM) monomer method (customary ethylene method and imported monomer method are collectively referred to as ethylene method).

According to the polymerization method of vinyl chloride monomer, the acquisition of polyvinyl chloride is divided into suspension method, emulsion method, ontology method and solution method. Suspension method is the main production method of polyvinyl chloride because of its simple production process, easy control and large-scale production, and strong product suitability; When the emulsion method polymerizes, water is used as the dispersion medium, and the particles obtained are relatively fine, and the thermal stability and electrical insulation are poor, which is suitable for the production of paste resin; The ontology method does not use water and dispersant, the post-polymerization treatment is simple, the product purity is high, but there is a problem of agitation and heat transfer in the polymerization process, the production cost is high, and it belongs to the elimination process; Solution polymerization is only used to produce coatings or specialty products.

Classification of polyvinyl chloride