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Time:14months ago
Source:Transform the World with Simplicity
PVC (polyvinyl chloride) is a common raw material for chemical production, which is widely used in construction, pipeline, wire and cable, packaging and other fields. The following are the manufacturing methods of PVC:
1. Suspension polymerization method
Suspension polymerization method is one of the main methods of PVC production, and its output accounts for more than 80% of the total output of PVC. The method is to add vinyl chloride monomer, water, dispersant, initiator and other raw materials together into a polymerization kettle, under the action of stirring and hot air, the vinyl chloride monomer is dispersed into numerous small droplets in water, each small droplet contains a certain amount of vinyl chloride monomer, and then the initiator is added to initiate polymerization to generate PVC resin. The advantages of the suspension polymerization method are low production cost, simple operation, and stable product quality, but it requires a large amount of water and dispersant, and the resulting wastewater needs to be treated.
2. Emulsion polymerization method
emulsion polymerization method is another PVC production method, its output accounts for about 10% of the total output of PVC. The method is to add vinyl chloride monomer, water, emulsifier and initiator and other raw materials together into the polymerization kettle, under the action of stirring to form an emulsion, and then add the initiator to initiate the polymerization reaction, resulting in PVC emulsion. The advantages of the emulsion polymerization method are that the heat of polymerization is easily removed, the reaction speed is fast, and the molecular weight distribution is narrow, but a large amount of emulsifier and wastewater treatment are required.
3. Bulk polymerization
Bulk polymerization is a PVC production method that does not use solvents or dispersants, and its output accounts for about 5% of the total output of PVC. The method is to add vinyl chloride monomer and initiator and other raw materials together into the polymerization kettle, polymerization reaction under high temperature and pressure, to produce PVC resin. The advantages of the bulk polymerization method are high product purity and good quality, but high temperature and high pressure conditions are required, and energy consumption is large.
No matter which method is used, the manufacturing process of PVC needs to strictly control the ratio of raw materials, reaction temperature and pressure and other parameters to ensure product quality and production safety. At the same time, because the PVC production process will produce waste water, waste gas and other pollutants, it is necessary to carry out strict environmental protection treatment to protect the environment and human health.
In short, the manufacturing method of PVC needs to be selected according to specific production conditions and product requirements. Different manufacturing methods will have a certain impact on the performance and quality of the product. Therefore, it is necessary to strictly control various parameters in the production process to ensure product quality and production safety.