As we all know, PVC-U pipe application began in the last century 30’s, has been more than 70 years of history, is a production technology, experimental testing, standardization, design and construction specifications are relatively mature products. PVC-U pipe is made of sanitary grade polyvinyl chloride (PVC) resin as the main raw material, adding appropriate amount of stabilizer, lubricant, filler, coloring agent and other plastic extruder extrusion molding and injection molding machine injection molding, through the cooling , Curing, stereotypes, inspection, packaging and other processes to complete the pipe, pipe production.

PVC pipe status
Chinese PVC pipe r production started in the last century 50’s, but before the 80s and the international advanced level, both the standard system, or processing technology are not a small gap. 80 years after the introduction of foreign advanced technology, and gradually establish a complete system of PVC-U pipeline system. In China’s various plastic piping system PVC pipe system, is the first to form a scale of production and a large number of applications. At present, Chinese PVC pipeline system has been popular to the construction of water supply, construction drainage, buried water supply, buried drainage, expansion casing, agricultural use and other fields, the estimated annual consumption of 1.3 million tons. But with China’s 13 million tons of PVC resin production capacity compared to only one-tenth. Therefore, compared with the international level there is still much room for development.

PVC pipe status
Chinese PVC pipe production started in the last century 50’s, but before the 80s and the international advanced level, both the standard system, or processing technology are not a small gap. 80 years after the introduction of foreign advanced technology, and gradually establish a complete system of PVC-U pipeline system. In Chinese various plastic piping system PVC pipe system, is the first to form a scale of production and a large number of applications. At present, China’s PVC pipeline system has been popular to the construction of water supply, construction drainage, buried water supply, buried drainage, expansion casing, agricultural use and other fields, the estimated annual consumption of 1.3 million tons. But with Chinese 13 million tons of PVC resin production capacity compared to only one-tenth. Therefore, compared with the international level there is still much room for development.

Advantages and Disadvantages of PVC-U Pipes
PVC-U products are widely used thanks to its good mechanical properties, as well as its economy and environmental protection. In a variety of thermoplastic pipe materials, PVC strength of the largest, the most inexpensive. PVC-U pipe short-term strength of up to 50MPa, 20 ° C, 50 years of long-term hydrostatic strength of not less than 25MPa (MRS reached 25MPa). The polyolefin pipe, the higher level of PEl00 MRS value of only 10MPa, PVC-U is its 2.5 times.
However, PVC-U has a big drawback. Toughness is not enough brittleness, impact resistance and resistance to cracking on the poor. In the external impact by the outside, it is prone to brittle damage. In the practical application process, especially in areas with complex geological conditions, falling stones and ditch at the bottom of the ditch may cause damage to the PVC-U pipe.

PVC-M performance characteristics
In many cases, we can see: the strength of the material may be very brittle. This is because the material itself is not very good absorption and resistance to red energy, the impact can be far greater than the material can withstand the ability to lead to material yield, direct fracture; the other hand, when the material has a small defect or gap And subjected to shock or external stress, it is possible to form a high stress at the tip of the notch, resulting in unpredictable crack development and final destruction. The addition of the appropriate modifier to the PVC-U material to produce PVC-M in a blend-modified manner can significantly improve the toughness without reducing the strength or slightly lower strength, making the material excellent Of the anti-cracking, anti-cracking. The physical and mechanical properties of PVC-M pipes and fittings are shown in Table 1 – Table 3.

Excellent impact resistance

PVC-M to maintain the strength of ordinary PVC-U pipe at the same time, improve the flexibility of the pipe. Good toughness to improve the impact resistance of Ding pipe, can effectively resist the installation and transportation process on the external impact of the pipe to improve the pipe anti-external damage ability.
After the system comparison test found: PVC-M pipe after the impact of toughness are damaged, in the pipe wall out of a small pit, the pipe body has not been damaged: but under the same conditions to do the test, PVC-U pipe by the impact After the occurrence of fragmentation, as shown in Figure 1 to Figure 2:

Excellent resistance to cracking and resistance to load
In practice, the pipe is inevitably damaged, or because of poor laying stress concentration, anti-cracking performance of the pipe is easy to lead to pipeline leakage, rupture, and because of crack propagation and brittle damage. Experience has shown that the majority of accidents in the past PVC-U pipes were “low stress brittle fracture”, that is, poor resistance to stress cracking.
The results of hydraulic test of incision pipe show that PVC-M has the ability of resisting point load, anti-stress cracking and anti-crack growth ability. Figure 3 is the PVC-M, PVC-U pipe incision test of the static hydraulic curve. It can be seen from Figure 3: PVC-M (incision) long-term strength is not affected, high reliability; PVC-U (with cut) long-term strength is significantly reduced, low reliability. As PVC-M pipe to reduce the sensitivity of the incision to eliminate the security risks, thus ensuring long-term, safe and reliable operation.

Save material
PVC-M by adding impact modifier to improve the toughness and enhance the safety of PVC-M material applications, you can reduce the design factor of the pipeline that the C value, the use of higher design stress. Thus, to achieve the purpose of reducing wall thickness and saving material. But also give full play to the advantages of PVC strength.
Table 4 and Table 5 lists the PVC-M and PVC-U related parameters. It is not difficult to see from the comparison of the two tables that the wall thickness of the PVC-M pipe is thinner than that of the PVC-U pipe under the same nominal pressure. Generally can reduce the current PVC-U pipe 25-30%.

BEIERl Machinery
Jiangsu Bell Machinery Co., Ltd., established in 1998, is Chinese leading manufacturer of plastic machinery and equipment. The company’s plastic pipe extrusion equipment, has been highly recognized by domestic and foreign customers, welcomed the new and old customers to visit the factory, negotiate.