Production method of special resin for gas-solid-phase-process chlorinated polyvinyl chloride and with medium-and-high polymerization degrees

Abstract

The invention relates to a production method of special resin for gas-solid-phase-process chlorinated polyvinyl chloride and with medium-and-high polymerization degrees. The production method sequentially comprises the following steps: preparation of an auxiliary agent, feeding into a polymerization kettle, material activation, variable-temperature polymerization reaction control and discharging, steam stripping and drying of PVC slurry. By adopting a variable-temperature polymerization mode, PVC granulation is completed at a proper temperature, the use amount of a dispersing agent is reduced, the grafting rate of the dispersing agent polyvinyl alcohol and vinyl chloride is reduced, a coating coverage rate is reduced, a polymerization chemical reaction rate is controlled by adjusting the temperature, and the method is simple, convenient, easy to implement, high in operability and good in reproducibility. The method can be widely applied to the production process of the special resin for gas-solid-phase-process chlorination of polyvinyl chloride.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a production method of a gas-solid phase chlorinated polyvinyl chloride special resin with a medium and high degree of polymerization. Background technique [0002] Chlorinated polyvinyl chloride (CPVC) is obtained by further chlorination of polyvinyl chloride (PVC), and is a new type of polymer elastomer material between rubber and plastic. After the PVC resin is chlorinated, the irregularity of the molecular bond increases, the polarity increases, the solubility of the resin increases, and the chemical stability improves, thereby improving the material's heat resistance, acid, alkali, salt, oxidant, etc. Corrosion. Compared with PVC, CPVC has greatly improved its heat resistance, corrosion resistance, flame retardant and self-extinguishing properties, and mechanical properties. It is widely used in building materials, electrical, chemical, metallurgy, medicine, coatin...

AI Technical Summary

Problems solved by technology

In the chlorinated polyvinyl chloride process produced by the gas-solid phase method, the chlorine gas molecules in the gas phase enter through the internal pores of the particles and undergo grafting reactions with the PVC molecular chains. The grafting rate and grafting uniformity are affected by the abundance of pores and the uniformity of pores. At the same time, the heat of grafting reaction is removed by circulating vulcanized chlorine gas to produce polyvinyl chloride resin. By adjusting the stirring speed of the polymerization tank and the type and amount of dispersant, the polyvinyl chloride resin can be significantly changed macroscopically. The particle shape of vinyl resin can adjust the particle size distribution and the roundness of the shape, and the internal void structure is also improved, but it is difficult to complete the regulation of the deep micro-nano structure of the resin. The specificity of ethylene production and application is not strong, especially when the gas-solid phase chlorination process is adopted, it is difficult to remove heat, which will cause poor thermal stability of chlorinated polyvinyl chloride resin