Explanation

linear low density polyethylene (LLDPE) is a kind of polyethylene formed by copolymerization of ethylene and olefins, with the content of copolymerized monomer ranging from 8% to 15%. Its density usually ranges from 0.91 to 0.925g/cm 3 Between. Different from low density polyethylene (LDPE), LLDPE has no long branched chains on the main chain in its molecular structure, but has short branched chains with uniform distribution. Generally, there are about 20 short branched chains on every 1000 carbon atoms of the main chain. This structural feature leads to the crystallinity of LLDPE being 55%, which makes it have some unique properties. The melting temperature of LLDPE is about 122 ° C, slightly higher than LDPE. Its properties such as transparency and mechanical properties depend on the type of copolymerized monomer used. LLDPE with longer and shorter branched chains typically has better flexibility, tear resistance, and impact resistance. LLDPE can be produced by low-pressure gas phase method, solution method and high-pressure method in industry. The specific structure of LLDPE gives it some significant advantages compared to LDPE. Because of its high melting point, LLDPE has a wider temperature range and better low-temperature impact resistance. Thin films with the same strength can be 20% to 25% thinner than LDPE in thickness. LLDPE is widely used in various application fields, including agricultural mulch film, warm cell (nuclear) covering film, stretch winding film, heat shrinkable film, steaming and boiling bag, packaging bag, wire and cable sheath, water pipe, various containers, bottles, cans, toys, etc. In addition, metallocene linear low density polyethylene (mLLDPE) is a special type of LLDPE, which is synthesized through metallocene catalyst and has narrow molecular weight distribution and uniform distribution of copolymer monomer. This makes mLLDPE superior to traditional polyethylene in terms of transparency, thermal viscosity, heat sealing temperature, and low odor. Therefore, it can be used for the production of heavy packaging bags, metal garbage bin liners, food packaging, stretched films, and other products.

Classification