PE pipes are used in a wide range of fields. Among them, water supply pipes and gas pipes are its two largest application markets.
PE resin is polymerized from the monomer ethylene. Due to the different polymerization reaction conditions such as pressure and temperature during polymerization, resins of different densities can be obtained, so there are high-density polyethylene, medium-density polyethylene and low-density polyethylene. Ethylene division. When processing different types of PE pipes, according to their application conditions, different resin grades are selected, and the requirements for extruders and molds are also different.
Internationally, the materials of polyethylene pipes are divided into five grades: PE32, PE40, PE63, PE80 and PE100, while the materials used for gas pipes and water supply pipes are mainly PE80 and PE100. There is no classification of special materials for polyethylene pipes in my country, which makes it difficult for domestic polyethylene gas pipe and water supply pipe manufacturers to choose raw materials, and also brings a lot of hidden dangers to the use of polyethylene pipes.
Therefore, the National Bureau of Standards has made a lot of revisions in the new standard GB/T13663-2000, which stipulates that different grades of PE80 and PE100 for water supply pipes correspond to different pressure strengths, and removes the tensile strength performance in the old standard, and increases the fracture. Elongation (greater than 350%), which emphasizes basic toughness.
PE water supply pipe PE pipes for water supply are the replacement products of traditional steel pipes and PVC drinking water pipes. The water supply pipe must withstand a certain pressure, and PE resin with large molecular weight and good mechanical properties, such as HDPE resin, is usually selected. LDPE resin has low tensile strength, resistance to pressure difference, poor rigidity, poor dimensional stability during molding and difficult connection, and is not suitable as a material for water supply pressure pipes. However, due to its high hygienic index, LDPE, especially LLDPE resin, has become a common material for the production of drinking water pipes. LDPE and LLDPE resins have low melt viscosity, good fluidity and easy processing, so the selection range of their melt index is also wide, usually MI is between 0.3-3g/10min.