PVC engineering plastics explanation of the causes of quality defects in extrusion forming of engineering plastics
Let' s take a look at the quality defects of engineering plastics extrusion.
PP-R (polypropelenerandom) pipe, namely random copolymer polypropylene pipe, is a new type of water pipe data widely used in developed countries. PP-R pipe has been used in Europe for more than 10 years. Because of its excellent performance, its market share is far ahead of other plastic water pipe data in recent years.
The production and application of PP-R pipes in China have also lasted for several years. With the vigorous promotion and application of chemical building materials by the state, China' s chemical building materials have entered the industrialization development stage, during which the development of new plastic pipes has reached a new climax again. At present, PVC-C, PE-X, aluminum-plastic pipes and PP-R pipes are almost used in the construction of hot and cold water and heating in China, and gradually transition to PP-R pipes.
The causes of cracking and leakage during the liquid net pressure test are as follows: according to the national specifications and rules, the production of PP-R pipes should use the normal PP-R resin that meets the requirements of gb/t1888742.1, and the materials should have a small required strength SMR guarantee value. However, some PP-R pipes use PP-R resins of different brands whose quality does not meet the requirements. There are too many branched chains in the molecular chain of this kind of PP-R resin, lacking SMR data, and the pipes produced by it have poor high temperature resistance; Although normal PP-R resin conforming to the requirements of gb/t1888742.1 is selected, due to disordered production management, impurities or moisture are mixed in the production process, so that there are visible impurities or bubbles on the surface of the pipe, and stress concentration will occur at the visible impurities or bubbles. Therefore, the liquid net pressure test of the pipe is unqualified.
Article source: PVC engineering plastics http://www.hhaifeng88.cn/
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