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The main material of the heat shrinkable sleeve is polyethylene, commonly known as PE. The following briefly introduces the chemical and physical properties of PE material.
Chemical properties: Polyethylene is resistant to a variety of organic solvents and acid and alkali corrosion, but it is not resistant to oxidizing acids, such as nitric acid. Polyethylene will be oxidized in an oxidizing environment.
Physical properties: Polyethylene can be considered transparent in the state of a film, but when it exists in a block shape, due to the large number of crystals inside, it will cause strong light scattering and opacity. The degree of crystallization of polyethylene is affected by the number of branches. The more branches, the more difficult it is to crystallize. The melting temperature of polyethylene crystals is also affected by the number of branch chains, which are distributed from 90 degrees Celsius to 130 degrees Celsius. The more branch chains, the lower the melting temperature. Polyethylene single crystals can usually be prepared by dissolving high-density polyethylene in xylene in an environment above 130 degrees Celsius.
Classification of polyethylene:
High Density Polyethylene (HDPE, High Density Polyethylene) is also called low pressure polyethylene, because it is produced under low pressure and contains more long chains, so it has a high density. Mainly used to manufacture various injection molding, blow molding and extrusion molding products.Medium Density Polyethylene (MDPE, Medium Density Polyethylene)
Low Density Polyethylene (LDPE, Low Density Polyethylene) is produced by a high pressure method (147.17-196.2MPa), which has many branches and low strength, and is mostly used to produce film products.Linear Low Density Polyethylene (LLDPE, Linear Low Density Polyethylene) and other products.
When Jiangsu Tongwei produces heat shrinkable tubing, it basically uses high-density polyethylene. High-density polyethylene is usually manufactured by Ziegler-Natta (Ziegler-Natta catalyst) polymerization method, which is characterized by no branches on the molecular chain. , So the molecular chain is arranged regularly and has a higher density. This process uses ethylene as a raw material in a tubular or kettle-type low-pressure reactor and uses oxygen or organic peroxide as an initiator to initiate the polymerization reaction.
high-density polyethylene material, heated to the melting point, can be recycled and reused.
