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Chlorinated polyvinyl chloride (CPVC) is a polymer material obtained after further chlorination of PVC.  The physical and chemical properties change significantly: with the increase of chlorine content, the irregularity of molecular chain increases and the crystallinity decreases; the polarity of molecular chain increases, the intermolecular force increases, the thermal deformation temperature increases significantly, and the mechanical properties are enhanced.

CPVC is far better than PVC in weather resistance, aging resistance and flame retardant.  For example, after chlorination, the limit oxygen index of PVC will rise from 45~49 to >70 (containing 67%CPVC chlorine), and the amount of smoke and residual carbon in the flame will be significantly reduced.  Chlorination process affected the properties of the products.  The chlorine content of PVC can be up to 73% after chlorination.

Generally by water phase suspension process, after mixing PVC resin, by chlorination, filtration, washing, CPVC production of neutralization, drying process is complete, the quality of the PVC powder material tree selection is very important, especially affecting machining stability, thermal stability), the selection of PVC resin raw material loose, leather as thin as possible, the structure of the neat degree of good.  The general chlorine content is 63%~67%.  Its weather resistance, corrosion resistance, aging resistance and flame retardant spontaneous combustion is far better than ordinary PVC resin.  The chlorine content increases, so vica softening point temperature significantly increased, 35℃ higher than PVC resin, the highest heat resistant temperature up to 130℃, suitable for heat resistant pipes and fittings and plates (such as hot water pipes, joints, heat resistant chemical equipment and storage tank).

UPVC is hard PVC. A modified material is prepared by adding a certain amount of modified additives on the basis of PVC tree powder.  ”U” is Unplasticized (Unplasticized), so the main difference between UPVC and PVC and soft PVC is that no plasticizer is added, more calcium powder, high mechanical strength of the material, suitable for the production of valves and pipelines.

CPVC is chlorinated polyvinyl chloride. Based on PVC resin, CPVC increases the chlorine content in PVC material by a certain process, generally ranging from 63 to 69%, so as to improve the heat resistance, acid, alkali, salt and oxidant corrosion of the material, and improve the thermal deformation temperature and mechanical properties of the material.

CPVC increases the chlorine content of PVC resin by chemical methods, so the material cost of CPVC resin is high. In the later stage, certain modified materials need to be applied to product injection or extrusion, resulting in high cost of CPVC modified materials. The selling price of CPVC modified particles in China is generally above 20,000 / ton.

Because of the high price of CPVC, it is impossible for this material to be applied as widely as UPVC. At present, CPVC is mainly used in fire fighting pipes, chemical corrosion resistant pipes and civil hot water pipes.