LDPE Prospects for development 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 company), Application of low density polyethylene Innovene, Samsung (innovene company) Total (Samsung Total) 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-end 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. PC resin is a polar non crystalline polymer, density: 1.380 g/cm3, glass transition temperature: 87 degrees C, so the thermal stability is poor, not easy to process. Can not be used directly, must be modified mixing, adding related additives and filler can be used. It is determined that the properties and requirements of the prepared PVC materials are different because of the different kinds and fractions of the additive and filler. We usually call it a PVC formula, which is strictly a PVC modified formula, and PVC is only modified to use. This class is often classified as polymer modified material. The modification of polymer materials mainly revolves around the high performance of general plastics, the conversion of single component materials to multi component materials and composites, and the functionalization and optimization of materials. In general, PVC should be modified to granulate first, and after the formation of particles by screw extruder, the plasticization is more sufficient and the processing is easier, especially the process is the injection product. The screw extruder is one of the most important equipments in plastic molding. It is used for solid conveying, compaction, melting, shearing and mixing extrusion of plastics through external power transmission and heat transfer of external heating elements. Screw extruders play an important role no matter as plasticizing and granulating machines?or?molding machines. Strictly speaking, there are special requirements for PVC products. PVC modified formula is made according to customer requirements. There are also copolymerization in the PVC production process, such as vinyl chloride copolymers, PVC blends, and chlorinated polyvinyl chloride (PVC) [3]. Performance indicators of PVC modification Colourability The thermal stability and light resistance of PVC are poor. Hydrogen chloride was decomposed at 150 C, with the adverse reaction of the plasticizer content. In addition, the influence of pigment on PVC is reflected in whether pigment is reacted with PVC and other components of PVC products, and pigment itself is resistant to migration and heat resistance. Some of the ingredients in the coloring agent may cause the degradation of the resin. For example, iron ions and zinc ions are the catalysts for the degradation of PVC resin. Therefore, the use of iron oxide (red, yellow, brown and black) pigment?or?Zinc Oxide, zinc sulfide and white pigment lithopone will reduce the thermal stability of PVC resin. Some of the coloring agents may be associated with the degradation products of PVC resin. Such as ultramarine pigment acid resistance is poor, so in the PVC coloring process, with the PVC decomposition of hydrogen chloride produced by the interaction of losing their color. Therefore, as far as PVC coloring is concerned, the characteristics of the resin and related auxiliaries are considered, and the characteristics of the pigments are combined. The following problems should be paid attention to when choosing a colorant. [4]