The chlorination process of CPVC is an aqueous phase suspension (slurry) chlorination process. The special PVC resin is subjected to displacement reaction with chloride ions under certain conditions to obtain a corresponding type of CPVC resin. Its molecular structure is: -CHCl-CHCl-CH2-CHCl-
Due to the increase in the chlorine content, the irregularity of the molecular structure of the CPVC is increased (the crystallinity is lowered and the polarity of the molecular chain is increased), so that the heat distortion temperature is increased. CPVC products can be used up to 93-100 ° C, 30-40 ° C higher than PVC, and improve the chemical and corrosion resistance of PVC. They are resistant to strong acids, alkalis, salts, fatty acid salts, oxidants and halogens. Chemical corrosion. In addition, the tensile strength and bending strength of CPVC are also improved compared with PVC. Compared with other polymer materials, CPVC has excellent aging resistance, corrosion resistance and high flame retardancy.
CPVC is widely used in the manufacture of various industrial pipes, hot and cold water pipes and fire pipes due to its excellent high temperature resistance, corrosion resistance and flame retardant properties. The superior performance of CPVC pipe is reflected in the following aspects:
1, strong, high temperature
Since CPVC is stronger than PP-R and PE-X, under the same pressure, CPVC can use the smaller pipe diameter to achieve the same water flow rate as PP and PE-X pipes, thus saving material cost and installation time. Compared with other thermoplastics, CPVC has excellent mechanical properties at different temperatures. It is suitable for pressure applications up to 93 ° C and a life of 50 years.
2, easy to install
The connection method is very similar to PVC. The most common and simplest method of attachment is solvent bonding. Other connection methods are threaded, flanged and electrode connections.
3, no oxygen corrosion
CPVC itself is resistant to oxygen, so there is no metal corrosion in the radiator due to oxygen permeation.
4, reduce the penetration of additives
To prevent oxidation, some modified plastics require the addition of large amounts of antioxidants that may penetrate the water supply system and cause an unpleasant odor.
5, not affected by chlorine in water
Many polyolefin materials (including PP, PE) may decompose when exposed to water, while CPVC will not be affected by residual chlorine in the water, without cracks and leakage.
6, good flame retardancy
CPVC has an oxygen limiting index of 60 and therefore does not burn in the air. It has no flame dew, does not increase the fire load, limits flame spread, and has low smoke generation characteristics.
7. CPVC has excellent chemical resistance to the strong acid and alkali. It is often used as a substitute for metals to treat aggressive materials such as poor quality water, acids, alkaline materials and other aqueous solutions.
8, low thermal conductivity
The heat transfer coefficient of CPVC is only 1.05, the heat is not easily dissipated from the pipeline, and the heat loss of the pipeline is small.
9, bacteria are not easy to breed
Since CPVC is not affected by residual chlorine in the water, cracks and leakage will not occur, the inner wall of the pipe is smooth, and bacteria are not easy to breed. Studies have shown that the growth of bacteria in CPVC pipes is much lower than other materials such as copper, steel and other plastic pipes.
10, lower thermal expansion
The coefficient of thermal expansion of CPVC is lower than that of other plastics. The expansion of the tube is very small when it is heated. Unlike other types of pipes (such as PP-RRP), the high expansion coefficient causes the meandering of the high temperature to be heated, and there is a safety hazard.