h an annual growth rate of 8%, and an annual demand growth rate of 2%. Among plastic pipes, the amount of PVC pipes has been far ahead, and it is widely used in water supply and drainage pipes. Due to the relatively mature technology, in recent years, PVc water supply pipes have not invested much in product innovation and relatively few new crystals. There are many ordinary products on the market, and there are few high-tech and high-value-added products. Similar general-purpose products and mid- and low-end products account for Most, few high-end products. At present, the domestic production capacity of plastic pipes is 3 million tons, mainly including PVC, PE and PP-R pipes. Among them, PVC pipes are the plastic pipes with the largest market share, accounting for nearly 70% of the plastic pipes. There are more than 1,600 PVC pipe production lines. The annual production capacity is more than 2.5 million tons. In 2003, the annual output of PVC pipes (pipe fittings) reached more than 1.2 million tons. In plastic pipes, PVC accounts for 70%, PE accounts for 25%, PP-R accounts for 4%, and others account for 1%. PVC pipe refers to the main raw material for pipes is PVC resin powder. The types of PVC pipes are generally classified according to the purpose of the pipes: drainage pipes, water supply pipes, wire pipes, cable sheathing...Because the raw material formulations are different, the pressure resistance of various types of pipes, etc. The indicators are different. PVC water supply pipes are used with water supply accessories for water supply projects in buildings. PVC drainage pipes are used for drainage and sewage. PVC industrial pipes are mainly used for corrosive pipeline transportation such as chemical industry, metallurgy, water treatment, medicine and electronics.