High-density polyethylene (HDPE), white powder or granular product. Non-toxic, tasteless, crystallinity of 80% to 90%, softening point of 125 to 135 °C, and use temperature up to 100 °C; hardness, tensile strength and creep are better than low density polyethylene; wear resistance, electrical Good insulation, toughness and cold resistance; good chemical stability, insoluble in any organic solvent at room temperature, corrosion resistance of acid, alkali and various salts; thin film permeability to water vapor and air, water absorption Low; poor aging resistance, environmental stress cracking resistance is not as good as low density polyethylene, especially thermal oxidation will reduce its performance, so antioxidants and ultraviolet absorbers must be added to the resin to improve this deficiency. High-density polyethylene film has a low heat distortion temperature under stress, so pay attention to it when applying it.
A brief history
In this century, there has been a revolutionary progress in the field of piping, that is, "replacing steel with plastic". With the rapid progress of polymer material science and technology, the deepening of the development and utilization of plastic pipes, and the continuous improvement of production processes, plastic pipes vividly demonstrate their excellent performance. Today, plastic pipes are no longer mistaken for "cheap substitutes" for metal pipes. In this revolution, polyethylene pipes are very popular, and they are increasingly dazzling. They are widely used in gas transportation, water supply, sewage, agricultural irrigation, mine fine particle solid transportation, as well as oil fields, chemicals, post and telecommunications and other fields, especially in It is widely used in gas transmission.
HDPE is a thermoplastic polyolefin produced by the copolymerization of ethylene. Although HDPE was introduced in 1956, the plastic has not yet reached maturity. This versatile material is constantly being developed for new uses and markets.
my country's domestic high-density polyethylene (here high-density polyethylene does not include high-density polyethylene produced by full-density polyethylene equipment) manufacturers include PetroChina, Sinopec, and CNOOC. As of the end of 2006, it belongs to PetroChina's high-density polyethylene. There are 4 sets of polyethylene plants, namely Lanzhou Petrochemical High Density Polyethylene Plant, Daqing Petrochemical High Density Polyethylene Plant, Liaoyang Petrochemical High Density Polyethylene Plant, Jilin Petrochemical High Density Polyethylene Plant.
High-density polyethylene is usually manufactured by Ziegler-Natta polymerization method, which is characterized by no branching on the molecular chain, so the molecular chain is arranged regularly and has a high density. In this process, ethylene is used as raw material in a tubular or tank-type low-pressure reactor, and the polymerization reaction is initiated with oxygen or organic peroxide as an initiator.
High-density vinyl is an environmentally friendly material, which can be recycled and reused when heated to the melting point. It should be noted that plastic raw materials can be divided into two categories: "thermoplastic" (Thermoplastic) and "thermosetting plastic" (Thermosetting). "Thermosetting plastic" is heated to a certain temperature and becomes a solidified state. Therefore, products with environmental problems are "thermosetting plastic" products (such as tires), not "thermoplastic" products (such as plastic pallets Note: pallets are called "plywood" in Hong Kong and Macau), so not all " Plastic" is not environmentally friendly.
