Among the characteristics of the hottest polyolefi

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Characteristics of polyolefin industry development (Part 2)

polypropylene and linear low density polyethylene occupy a more important position

polypropylene has a faster demand growth rate than polyethylene. From 1996 to 2001, the average annual growth rate of world polypropylene demand was 8.03%, while that of polyethylene was 4.19%. In 1996, the proportion of world demand for polyethylene and polypropylene was 1.9:1. By 2001, this proportion had changed to 1.58:1. In 1996, the output ratio of polyethylene and polypropylene in China was 1. The printing material developed for HP jet fusion 3D printer was.21:1, and the ratio of performance demand was 1.50:1; In 2001, the proportion of output changed to 0.95 ∶ 1, and the proportion of apparent consumption changed to 1.37 ∶ 1. Compared with most countries in the world, China has relatively rich polypropylene resources and a wider range of polypropylene applications

among the three polyethylene products, the consumption ratio of HDPE, LDPE and LLDPE in the world in 1996 was 43:36:21; By 2001, the consumption ratio of the three has changed to 43:33:24, and LLDPE has a faster growth rate of consumption. From 1996 to 2001, the annual average growth rate of LLDPE consumption in the world was 5.91%, which was respectively the elastic deformation, plastic deformation and fracture of materials, while HDPE and LDPE were 4.06% and 2.05% respectively in the same period. The approximate proportion of the output of HDPE, LDPE and lldpe3 polyethylene products in China in 2001 was 41:28:31. Because many lldpes are produced in full density polyethylene units, we assume that 2/3 of the products produced by LLDPE units including full density polyethylene units are calculated as LLDPE, and the remaining 1/3 is included in HDPE output. Compared with the world average proportion in 2001, the proportion of LLDPE in China is significantly higher than the world average level

the above comparison shows that polypropylene and linear low-density polyethylene, two fast-growing polyolefin varieties, have a more prominent position in China's polyolefin industry. Developing new products of these two varieties and developing the application substitution of these two products for other resins are of special significance to the development of China's polyolefin industry

III. The progress of catalyst and process technology has expanded the scope of product application

the progress of catalyst and process technology ensures the lubricity between bearings; In order to ensure the sharpness of the knife cut, it has the ability to produce products "tailored" according to the user's requirements. In recent two to three years, the main progress of polyethylene products is the development of LLDPE and HDPE resins with good strength and easy processing; The important progress of polypropylene products is the development of impact copolymer with good balance of rigidity/toughness/fluidity. In addition, the application scope of polypropylene has been expanded to pressure resistant pipes and window profiles

when LLDPE came out in the 1970s, many people predicted that LLDPE would completely replace LDPE because of its low production energy consumption and high film strength. However, after 30 years, LDPE's share in the world polyethylene market still exceeds that of LLDPE, mainly because its processability and transparency cannot reach the level of LDPE. At present, one of the hotspots in the development of LLDPE and HDPE is to further improve the processability and performance of the resin. "Bimodal" resin is one of the easy processing resins. Bimodal technology has a history of more than 10 years, but due to the use of two reactors to produce high and low molecular weight resins, the product price is higher. Recently, due to the progress of catalyst and reactor operation technology, the economy of bimodal brand has been significantly improved. Almost all the world's large polyethylene production companies can produce bimodal resin. Bimodal technology was originally used in HDPE and has now been extended to LLDPE

in order to reduce the cost, the technology of producing bimodal resin with one reactor has been under development. Univation has successfully developed the technology of producing bimodal HDPE in one reactor, and has been industrialized in Unipol reactor for 6 days, producing 3000t bimodal HDPE. The processability and physical properties of the product have achieved a good balance. It is expected that the technology of producing bimodal resin with one reactor will be able to sell patent licenses in early 2003

for a long time, the consumption growth rate of polypropylene copolymers has exceeded that of ordinary homopolymers because of their better low-temperature toughness. The proportion of polypropylene copolymer in polypropylene products is increasing year by year. In 2001, in the United States, polypropylene homopolymer accounted for 70% - 75%, impact copolymer accounted for 15% - 22%, and random copolymer accounted for 8% - 10%. Under the condition that the market of conventional high-tech biomedical materials in China is basically monopolized by foreign investors. In Japan, due to the many applications of injection molding, as early as the 1980s, the copolymer proportion reached more than 40%. While the quantity increases, the improvement of the quality of impact copolymer is more prominent. In recent years, almost all large polypropylene production companies in the world have made significant progress in the technology of directly producing impact copolymer (ICPP) in reactors. First, the balance of rigidity, toughness and processability of ICPP is further improved; Second, the functionality of ICPP is improved, and paintable bumpers can be made. These advances are mainly attributed to the progress of Z-N catalytic Liu technology and rubber dispersion technology. In general, the improvement of one performance is often at the cost of the decline of other performance, but the use of new catalysts can make the products have higher adhesion and toughness on the premise of unchanged fluidity, so that the processing plant can get benefits in shortening processing time, increasing mold cavity and further thinning

due to the development of polypropylene resin with high rigidity, high toughness and high melt strength, the application scope of polypropylene has expanded to the plastic pipe market dominated by PVC and HDPE and the window profile market dominated by PVC. (to be continued)

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