The full name of PVC is Polyvinylchlorid, whose main component is polyvinyl chloride. In addition, other proportioning ingredients are added to enhance its heat resistance, toughness and ductility. The uppermost layer of this surface film is lacquer, the main component in the middle is polyvinyl chloride, and the lowermost layer is a back-coated adhesive.
The PVC pipes we see in our daily life have two categories: hard PVC pipe and soft PVC pipe. Among them, the hard PVC pipe has a nominal outer diameter of 50cm, but the maximum outer diameter of the soft PVC pipe is generally 50mm.
It is understood that compared with other materials, PVC pipe has many advantages: First, PVC pipe has good tensile strength and good compressive strength; the disadvantage is that its flexibility is not as good as other plastic pipes. Second, the pipe wall of the hard PVC pipe is very smooth, the resistance to the fluid is very small, the roughness coefficient is only 0.009, the water delivery capacity is 20% higher than that of the cast iron pipe, and 40% higher than the concrete pipe of the same pipe diameter. Third, the hard PVC pipe has excellent acid resistance, alkali resistance and corrosion resistance. It is not affected by moisture and soil pH, so it does not require any anti-corrosion treatment when laying hard PVC pipe. Fourth, when installing hard PVC pipe, whether it is bonded or rubber ring connection, it has good water tightness. Fifth, compared with other materials, PVC pipe prices are relatively moderate, suitable for the majority of consumers...
According to statistics, the current production capacity of plastic pipes in China is 3 million tons, mainly including PVC, PE and PP-R pipes. Among them, PVC pipe accounts for the largest market share of plastic pipes, and the market share of plastic pipes near the station is the largest. 70%, in addition, PE tubes account for 25%, PP-R tubes account for 4%, and others account for 1%.
At present, China's PVC pipe production line has more than 1,600 pieces, with an annual production capacity of over 2.5 million tons. In 2003, the annual output of PVC pipes reached more than 1.2 million tons. Although the rapid development of PVC pipes has attracted many enterprises to invest in this industry, among the more than 2,000 domestic manufacturers, there are only 70 manufacturers with an annual output of 10,000 tons, and 20 enterprises with an annual output of over 30,000 tons. A number of and have 60% of the industry's output. On the whole, China's small-caliber, low-value-added pipeline enterprises are too large, and there are too few large-caliber and high-tech enterprises. This has seriously affected the production efficiency and quality of China's plastic pipes, and also slowed down the development speed.
It is reported that at this stage, the distribution of processing capacity of PVC pipes in China is structurally unreasonable. The processing capacity of small and medium-sized enterprises is mainly concentrated in PVC drainage pipes. At the same time, a large number of non-standard pipes still flood most of the market, resulting in disorderly and chaotic market competition, and the price of PVC pipes is also disorderly.
In some traditional PVC plastic pipe areas, the replacement momentum of PE and PP-R is obvious. The ban on market share of nibble and lead-containing stabilizers in PVC pipes in contact with food products will have a certain negative impact on the development of PVC pipes. In particular, PVC raw materials generally account for 70-80% of the total cost, and the change in the price of the main raw material PVC has a significant impact on the enterprise.
Since 1998, the capacity of plastic pipes has expanded and market competition has intensified. The price of PVC pipes has fallen, while the prices of PVC raw materials have risen and the profits of the industry have fallen. Many small and medium-sized enterprises have been shoddy and shoddy to survive. The PVC pipe itself is a waste of transportation loading space, and the introduction of new road traffic regulations further increases transportation costs.
Experts believe that PVC pipe should have better development, or start from improving the technical content, improve the technical content, and increase the production efficiency; further improve the quality of PVC pipe to further promote the industry faster and better. development of.