the chemical difference of pvc upvc cpvc1. PVC
PVC (PolyVinylChloride) generally has 7 grades (SG1-SG7) according to the hardness and performance of the material, and the density is about 1.4 g / cm ^ 3. Below SG4 is generally a soft product, and a large amount of plasticizer needs to be added during molding. It is mainly used to make artificial leather, wire and cable insulation, and seals. SG5 and above are hard products, mainly used to make various pipes, such as drainage, electricians, post and telecommunication pipes and pipe fittings, various plates, sheets, profiles, etc. PVC molding shrinkage is 0.6-1.5%, has good mechanical properties, excellent electrical properties, and self-extinguishing, strong acid and alkali resistance, good chemical stability, low price, is a very widely used Of universal plastic. But because its use temperature is not high, the highest is about 80 ℃, which hinders its development.
The resin is made of polyvinyl chloride (PVC) resin through chlorination modification and is a new type of engineering plastic. The product is white or light yellow loose particles or powder which is odorless, odorless and non-toxic. After PVC resin is chlorinated, the irregularity of molecular bonds increases, the polarity increases, the solubility of the resin increases, and the chemical stability increases, thereby improving the heat resistance, acid resistance, alkali, salt, oxidizing agent, etc. of the material Of corrosion. The mechanical properties of the heat distortion temperature have been improved. The chlorine content has been increased from 56.7% to 63-69%. The Vicat softening temperature has been increased from 72-82 ℃ (increased to 90-125 ℃). Long-term use temperature is 95 ℃. Among them, the performance index of CORZAN CPVC is better. Therefore, CPVC is a new engineering plastic with broad application prospects.
The tube uses polyvinyl chloride resin as a carrier, which has excellent characteristics such as accurate temperature sensitivity, timely melting, and rapid absorption of the active ingredients of additives when weakening the gravitational force between the resin molecular chains. At the same time, it uses the world-famous calcium-zinc composite heat stabilizer In the process of resin being subjected to high temperature and melting, it can capture, inhibit, absorb and neutralize the release of hydrogen chloride, and perform double bond addition reaction with the polyene structure to replace the active and unstable chlorine atoms in the molecule. So as to effectively and scientifically control the catalytic degradation and oxidative decomposition of the resin in the molten state.