LLDPE The production of LLDPE begins with the transition metal catalyst, especially the type of Ziegler (Ziegler)?or?PHILPS Phillips. A new process based on the catalyst for the cyclic olefin metal derivatives is another option for LLDPE production. The actual polymerization can be carried out in the solution and gas phase reactor. Both LDPE and LLDPE have excellent rheological?or?melt fluidity. LLDPE has smaller shear sensitivity because it has a narrow molecular weight distribution and a short branched chain. During the shear process (for example, extrusion), LLDPE maintains a greater viscosity, and thus is difficult to be processed than the same melting index of LDPE. In extrusion, the lower shear stress of LLDPE makes the stress relaxation of polymer chains faster, and the sensitivity of physical property to the change of blow up ratio is reduced. In the melt extension, LLDPE usually has lower viscosity at various strain rates. That is to say, it will not strain hardening as the LDPE is stretched. The increase in the deformation rate of polyethylene (.LDPE) shows an astonishing increase in viscosity, which is caused by molecular chain entanglement. This phenomenon is not observed in LLDPE, because the lack of long branched chains in LLDPE makes the polymer not entangled. This performance is very important for the application of thin films, because the LLDPE thin films are easy to make thin films under high strength and toughness. Classification /LLDPE LLDPE Atlas According to the type of copolymerized monomers, LLDPE is mainly divided into 3 kinds of copolymers: C4 (butene -1), C6 (hexene -1) and C8 (octene -1). Among them, butylene copolymer is the largest LLDPE resin in the world, while hexene copolymer is the fastest growing LLDPE variety at present. In the LLDPE resin, the typical dosage of the copolymerized monomer is 5% to 10%, with an average amount of about 7%. The metallocene based LLDPE plastic body (mLLDPE) has more than 3 times the average content of the average copolymerized monomer of the traditional LLDPE. Figure 1 shows that the world is 10 years since their 3 monomers yield of LLDPE. At the end of 1984, the co carbon company introduced the production of hexene copolymerized LLDPE, followed by Exxon, Mobil and other companies. Dow Chemical (Dow Chemical Company) almost used octylene as comonomer in its low pressure solution process, and NOVA Canada (Nova chemical) also used octylene in most of the pressure solution process. The copolymerization of octyl LLDPE resin has a little good strength, tearing resistance and processing property, but the properties of hexene copolymerization and octyl copolymers have little difference. Hexene LLDPE resin manufacturers including ExxonMobil Chemical (Exxon Mobil chemical company), Eastman Chemical (Eastman Chem Co), Equistar (star company) and Chevron Phillips (Chevron Phillips chemical company) etc.. In addition, Dow Chemical (Dow Chemical Company), Basell (Basel), Innovene (Samsung, Total, innoven) (Samsung Total (micro-blog), etc.) also produce 1-hexene LLDPE. Compared with the commonly used butene copolymers, the LLDPE produced by hexene and octene as copolymerized monomers has better performance. The largest use of LLDPE resin in film production, with a long chain alpha olefin (such as cyclohexene, 1-octene) as comonomer production of LLDPE resin and film products in the tensile strength, impact strength, tearing strength, penetration resistance, environmental stress cracking resistance and many other aspects are better than by butene as comonomer to produce LLDPE resin. Since 1990s, PE manufacturers and users in foreign countries tend to replace butylene with hexene and octene. It is reported that using octene as comonomer, the performance of resin is not necessarily better than that of hexene copolymerization, and the price is more expensive. Therefore, the trend of using LLDPE abroad to replace butene is more obvious. Because there is no large-scale production of hexene and octene in China, and the import price is more expensive, the LLDPE resin currently used in China is mainly used as butene as comonomer. Some enterprises in China used the LLDPE as the monomer of the comonomer when they introduced the production plant, but they had to give up because of the production of no hexene in China, and only imported a small amount of hexene when driving. Most of the high grade LLDPE imported from China are such products. It is expected that in the future, there will be a greater increase in the demand for LLDPE with 1- hexene as a monomer. Performance /LLDPE Cold tolerance of LLDPE, the relationship between catalytic temperature and melt flow rate of LLDPE brittle temperature than LDPE, HDPE are low, which indicates that the resistance to low temperature. Physical and mechanical properties MDPE molecular structure In the main chain of MDPE molecule, there are 20 methyl branched chains?or?13 ethyl branched chains on the average of every 1000 carbon atoms, and their performance depends on the number and length of branched chain. Copolymerization can increase the link chain between small crystals of its crystal Performance characteristics and parameters MDPE is characterized by long term retention of resistance to environmental stress and strength. The relative density of MDPE is 0.926-0.953, the crystallinity of 70%-80%, the average molecular weight is 200 thousand, the tensile strength is 8-24 MPa, elongation at break of 50%-60%, the melting temperature of 126-135 DEG C, the melt flow rate of 0.1-35 g /10 minutes, the heat deformation temperature of 49-74 DEG C (0.46 MPa). Processing technology It is divided into three kinds: high pressure method, low pressure method and medium pressure method. High pressure method is used to produce LDPE. This method has been developed very early. Polyethylene produced by this method accounts for about 2/3 of the total output of polyethylene. However, with the development of production technology and catalyst, its growth rate has lagged behind the low pressure method. The low pressure method includes slurry method, solution method and gas phase method for its application. Slurry method is mainly used to produce HDPE, while solution method and gas phase method can not only produce HDPE