The big market era of hexene copolymerized polyethylene is coming

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Since the U.S. company UCC used ethylene and α-olefin copolymerization to produce LLDPE in 1977, foreign countries have made great progress in using copolymerization technology to modify PE in recent years. One of the obvious developments in the low-pressure PE process is the transformation of the comonomer of HDPE and LLDPE from 1-butene to longer carbon chain α-olefins such as 1-hexene, 1-octene and 4-methyl-1-pentene (4-MPI). With the successful development of new catalysts with good copolymerization properties and the application of condensed and super-condensed feed technology, many companies have been able to economically and effectively produce advanced α-olefin copolymerized PE resins. At present, LLDPE products in the United States and Europe are basically ethylene/l-hexene copolymers. In Asia, due to differences in comonomer resources and application status, LLDPE products are still mainly ethylene/l-butene copolymers. At present, the world's major manufacturers of hexene copolymerized PE resin include ExxonMobil Chemical, Eastman Chemical, Star Company, Chevron Phillips Chemical, Dow Chemical, Basel, Yinuo, Nova Chemical and Samsung Total. 　Global polyethylene demand is expected to grow at an average annual rate of 4.4% by 2015, and LLDPE will grow at an average annual rate of 6.2%. During the same period, the growth rate of low-density polyethylene (LDPE) will be only 1.8%, and HDPE will grow at an average annual rate of 4.6%. Although the PE production capacity in Asia will increase by 5.2 million t/a from 2004 to 2008, accounting for 40% of the total global PE capacity increase, Asia will continue to be a net import area of ​​PE. According to Univation's forecast, global PE consumption will reach 87.4 million tons by 2010, of which HDPE consumption will increase by 51% (about 18 million tons), LLDPE will increase by 45% (about 16 million tons), and LDPE will increase by 4%. It can be seen that the growth of PE is mainly concentrated in HDPE and LLDPE products. Calculated with reference to the consumption ratio in the United States, 1-hexene copolymer products account for about 30% of LLDPE, and 1-hexene copolymer products of HDPE account for 55%. It is expected that by 2010, the global production of HDPE and LLDPE with 1-hexene as a copolymer component will increase by about 14 million tons. Replacing l-butene with 1-hexene to produce high-performance LLDPE and HDPE has become an inevitable trend in future development. Demand for hexene copolymer PE will depend on imports. 　In recent years, my country's PE industry has developed rapidly, with production capacity and consumption increasing continuously. In 2006, my country's total PE production capacity reached 7.225 million t/a, and apparent consumption reached 10.844 million t. It is expected that consumption will reach about 15 million tons by 2010, of which HDPE will be about 3 million tons and LLDPE will be about 7.5 million tons. By then, the potential consumption of 1-hexene copolymer will reach about 3.7 million tons. At present, the domestic market mainly relies on imports, except for the hexene copolymer produced by Shanghai Jinfei Petrochemical Co., Ltd. Most of my country's HDPE and LLDPE production equipment imported foreign technology from the 1970s to 1980s, with fewer product grades. Although 1-hexene copolymer grades were included in the units introduced later, due to the lack of 1-hexene resources in the country, 1-hexene copolymer grades were only trial-produced during the initial start-up assessment and acceptance period. The HDPE and LLDPE units of Qilu Petrochemical Company both use the gas phase technology of UCC Company of the United States. The company once trial-produced hexene copolymerized high-end gas pipe special material DGD2400 (density 0.939g/cm3, MFR 14g/10min) in its HDPE production equipment. The 1-hexene raw material was imported from abroad. However, due to cost and 1-hexene source issues, the company did not continue to produce this grade. Recently, Qilu Petrochemical developed and produced hexene copolymer PEl00 grade pipe material base resin DG-DB2480H in its polyethylene unit, and prepared a black compound DG-DB2480HBK with excellent performance. Both products have passed the PEl00 grade certification of the Swedish Bodycote Laboratory, an internationally authoritative pipe material grade certification department, and their performance meets the performance requirements of PEl00 pipe materials for water supply pipes and gas pipes. In addition, the company also trial-produced QLLF05 hexene copolymer LLDPE stretch film special material and put it on the market in small quantities. 　 The LLDPE unit of Daqing Petrochemical Company also introduced Unipol gas phase technology from UCC Company of the United States. The device only produced 1-hexene copolymer products on a trial basis when it was newly built. However, due to the high price of imported 1-hexene products at that time, it was not produced again. In 2007, Daqing Petrochemical Company carried out another transformation during the overhaul of the PE unit and began to produce linear metallocene polyethylene products. Linear metallocene catalyst ethylene reaction uses ethylene and 1-hexene as raw materials, hydrogen as molecular weight regulator, and under the action of metallocene catalyst, fluidized bed gas phase polymerization is performed at low pressure, and linear metallocene polyethylene is refined through degassing, granulation and other processes. The linear polyethylene products produced have a narrow molecular weight distribution and a uniform composition distribution of comonomers between molecular chains. These structural characteristics make linear metallocene polyethylene have good optical transparency, excellent low-temperature impact properties, high tear and puncture resistance, low heat sealing starting temperature and excellent sealing performance compared with conventional LLDPE resin films. The linear metallocene polyethylene developed by Daqing Petrochemical Company has filled the gap in the production of this cutting-edge product in my country. 　Tianjin Lianhua Company introduced a set of 60,000 t/a LLDPE production equipment in 1996, using the gas phase technology of the American UCC Company. The company has produced three types of 1-hexene copolymer products, among which domestic hexene is used as the comonomer. It has independently developed the production technology of DFDA-9030, a special material for hexene copolymer stretch film. This product can meet the requirements of domestic stretch film manufacturers, replace imported similar raw materials, and break the monopoly market situation of imported products. 　Shanghai Jinfei Petrochemical Co., Ltd. is currently the only domestic manufacturer that can use all 1-hexene as a comonomer for large-scale PE (mainly HDPE) production. The production process adopts the loop slurry method of Phillips Company, using isobutane as the diluent, the catalyst is chromium, the ethylene conversion rate is 99%, and the production capacity is 100,000 t/a. The company's 7 series and 23 brands of hexene copolymer products have been very popular since they were put into production and introduced to the market in 1998. They have occupied the high-end market of special materials for various uses of PE resin. The products are extremely competitive. The product uses include blow molding, pipes, films, injection molding, monofilaments/flat filaments, wires/cables, etc. 　In addition, Maoming Petrochemical Company has also reported the production of special materials for hexene copolymer LLDPE stretch film. The brand is 6080, and the market volume is small. ； Yangzi Petrochemical Co., Ltd.’s hexene copolymer product 7001 is still in the industrial trial production stage. Accelerate technological research and development of special materials for hexene copolymerization (1) Hexene copolymerized polyethylene products have been produced in large quantities abroad and have been widely used, and will continue to develop further in the future. Our country should also speed up the research, development and production of hexene copolymerized polyethylene products to improve the quality of our polyethylene products and replace imports. 　(2) The key to producing hexene copolymerized polyethylene products is the source of raw material hexene. Beijing Yanshan Petrochemical Company Research Institute independently developed a complete process technology for ethylene trimerization to 1-hexene, which was completed and put into production in the first half of 2007. The product quality can meet the quality requirements of ethylene comonomer. The completion and commissioning of this device will effectively promote the development of domestic hexene copolymerized PE products. 　(3) According to the current production status of polyethylene products in my country and the development trend of polyethylene products in the world, domestic efforts should be made to produce special materials for blow molding of ethylene-hexene copolymerized polyethylene, and to develop special materials for hexene copolymerized polyethylene rotational molding and high-quality hexene copolymerized polyethylene cable materials to meet the growing domestic demand.