Quin tipus de material és el PVC?
Clorur de polivinil, anomenat PVC, is a polymer made of vinyl chloride as a monomer through free radical polymerization. Because the electron-withdrawing substituent of the chlorine atom on vinyl chloride is p-π conjugated, has an electron-donating effect, and is not easily attacked by carbanions, so free radical polymerization can only be used. The current PVC polymerization process includes suspension polymerization (above 80%), bulk polymerization (about 7%), emulsion polymerization, microsuspension polymerization, etc.
PVC has good impact resistance, mechanical strength, dielectric properties and other aspects, so it has a wide range of applications and was once the world's largest output of general-purpose plastics. Common products include coatings, pipes, plastic steel, carpets, packaging materials, etc. There are two common preparation methods for PVC monomer vinyl chloride (VCM). One is the addition of acetylene and HCl to produce vinyl chloride. The raw material calcium carbide in this method comes from coal, and it requires a lot of electricity, which consumes a lot of money and costs a lot. high. (Some domestic factories still use this method.) Another method is the ethylene oxychlorination method, in which ethylene and chlorine generate 1,2-dichloroethylene and then crack to generate vinyl chloride. Because the main raw materials come from petroleum and alkali industry, low energy consumption and low cost, it is now gradually replacing the calcium carbide method.
El clorur de vinil és un carcinogen, i el clorur de polivinil conté monòmers residuals de clorur de vinil. Per tant, el policlorur de vinil té certa carcinogenicitat i va ser catalogat com a carcinogen de tercera classe el 2017. (Els carcinògens comuns de Classe 3 inclouen gasolina, dièsel, pilotes sanitàries de naftàl, etc.) El procés actual de producció del PVC ha pogut garantir que el contingut residual de monòmers al PVC sigui extremadament baix, i el PVC qualificat es pugui utilitzar de manera segura en envasos d'aliments i altres aspectes.
PVC has good impact resistance, mechanical strength, dielectric properties and other aspects, so it has a wide range of applications and was once the world's largest output of general-purpose plastics. Common products include coatings, pipes, plastic steel, carpets, packaging materials, etc. There are two common preparation methods for PVC monomer vinyl chloride (VCM). One is the addition of acetylene and HCl to produce vinyl chloride. The raw material calcium carbide in this method comes from coal, and it requires a lot of electricity, which consumes a lot of money and costs a lot. high. (Some domestic factories still use this method.) Another method is the ethylene oxychlorination method, in which ethylene and chlorine generate 1,2-dichloroethylene and then crack to generate vinyl chloride. Because the main raw materials come from petroleum and alkali industry, low energy consumption and low cost, it is now gradually replacing the calcium carbide method.
El clorur de vinil és un carcinogen, i el clorur de polivinil conté monòmers residuals de clorur de vinil. Per tant, el policlorur de vinil té certa carcinogenicitat i va ser catalogat com a carcinogen de tercera classe el 2017. (Els carcinògens comuns de Classe 3 inclouen gasolina, dièsel, pilotes sanitàries de naftàl, etc.) El procés actual de producció del PVC ha pogut garantir que el contingut residual de monòmers al PVC sigui extremadament baix, i el PVC qualificat es pugui utilitzar de manera segura en envasos d'aliments i altres aspectes.