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  PE80, PE100 is the base resin for the production of pressure-bearing plastic pipe. In particular, PE100 is the only polyethylene grade in the domestic and international high-pressure pipelines. It can be widely used for pressure pipes, gas pipes and various industrial pipes. PE100 has excellent melt flow, weatherability and long-term stability, from its production as a raw material pressure pipe at 8.0MPa, 20 ℃ conditions, to ensure 50-year service life. At the same time its outstanding resistance to rapid crack extension and anti-slow crack growth performance, and save material, save energy and other outstanding advantages, in line with today's environmental protection and energy saving requirements, by the market and users. It can be said that PE100 is a leader in the field of high-performance pipeline specialty materials, representing a country's high-pressure pipe production technology.

  First, under pressure plastic pipe basic resin properties

  PE pipe According to the production of polyethylene pipe of different raw materials, can generally be divided into three generations: the first generation, equivalent to the current level below the PE63 PE63 tube material; the second generation, equivalent to the current PE80 PE pipe material; third generation , That is more excellent performance PE100 pipe material. At present, many large-scale petrochemical enterprises in the world have mass-produced PE100 grade pipe materials. In recent years, they have developed PE125, the fourth-generation PE pipe material, but have not yet entered industrialized production.
  The second and third generation PE pipes not only significantly increase the long-term strength, but also improve the resistance to environmental stress cracking and other properties. In the same pressure can reduce the wall thickness, increase the delivery cross-section, improve transport capacity. As the obvious economic benefits, can be applied to the larger diameter, the use of the environment is poor (such as low temperature areas, the sea floor). Therefore, the application of pressure PE pipe is very broad.
  Under pressure plastic pipe of the base resin, such as the third generation of PE100 polyethylene material is a specific binary distribution of pipe resin, its structural features are finely controlled molecular weight distribution and composition distribution, high molecular weight fractions and low molecular weight fractions About half. The high molecular weight fractions contain comonomers that generate a large amount of linker molecules that link the lamellae together, providing high long-term strength and rapid crack growth resistance. The low molecular weight fraction is a homopolymer which ensures high crystallinity and rigidity of the resin and acts as an internal processing aid when melted to provide a low viscosity of the PE melt at high shear rates thus providing Good processability. This resin can be used for 250mm diameter, high pressure gas pipe or 500mm diameter, high pressure water supply pipe.

  Second, the domestic PE80, PE100 pipe material development and market status quo

  (A) the status of the domestic market
  In recent years, the rapid development of polyethylene pipe in our country, but the development of its special materials can not keep up the pace of pipe production, but also relatively lagging behind. At present, although several PE pipe and PE100 grade polyethylene pipe materials have been introduced from abroad, there are still some problems that the grades are not homogeneous and the specifications are not compatible. Every year, a large amount of special resin needs to be imported. PE80 grade polyethylene pipe material to import tens of thousands of tons each year, mainly for the manufacture of gas pipe, all kinds of water pipes and other pressure piping systems. Now there are many water supply pipe companies with better domestic special materials, such as Shanghai Petrochemical YGH041T (PE100), QDB Petrochemical DGDB2480H, Yanhua 6100M and Jinfei TR480 and so on.

  (B) the domestic PE80, PE100 pipe material development
  Shanghai Petrochemical uses high-value-added black pipeline material YGH051T (PE80) (MFR0.75, density 0.94) and YGH041T (PE100) (MFR 0.4, density 0.949) manufactured by Nordic Chemical's "NorthStar Twin Peaks" technology to fill the domestic blank , And passed the Swedish national test and certification as well as the long-term performance certification of PE100 according to ISO9080 standard. This marks the first PE100 domestic polyethylene pipe special material access to the international "pass", at the same time reflects the pressure pipe PE base resin technology in China a huge breakthrough.
  Yangzi Petrochemical Research Institute also introduced in recent years high-performance polyethylene pipe materials, and the success of industrial tests, the performance basically reached the level of PE100. The structure of this material is bimodal in molecular weight distribution, giving the resin excellent physical properties and a perfect combination of creep resistance, crack resistance and good workability.
  Yanshan Petrochemical Company in 2001 developed HDPE6100 pipe material, has been identified by Sinopec, which belongs to the hollow extrusion products. In addition, the company produces high-quality pipe material HDPE 6380M is the earliest developed bimodal molecular weight distribution of high-grade pipe material, the performance of the PE80 pipe material requirements.
  Domestic pipe material grades, Qilu Petrochemical DMD2480 is a better low-pressure gas pipe dedicated material, the performance equivalent to PE80. DMD2480 has high melt strength, tear strength and good resistance to environmental stress cracking (1500h above), excellent processing performance, product appearance and smooth, good gloss, seams, high quality knot. In 2005, QIBL Petrochemical Company Plastic Factory and the Institute of Resin to develop and produce hexene copolymerization of polyethylene pipe materials DGDB2480H and DGDB2480HBK, passed the international authority of the tube material level certification body Sweden BODYCOTE laboratory PE100 level certification.

(C) common domestic imports PE80, PE100 pipe material grades and characteristics

  Common domestic imports of PE80, PE100 pipe material grades are: Korea Petrochemical PE100-P600, PE100-P600BL PE80-P301EBL, PE80-P601KUBL, PE80-P502BL, France Atofina PE100-XS10B, Formosa Plastics 8001, South Korea LG PD0100, etc.,

  Third, the development of new foreign pipe material dynamics

  (A) Atofina company
  Atofina has developed a new product that represents the fourth generation of pipe resins with its proprietary double-pipe process. The first generation of this new family of bimodal ethylene-hexene copolymers, called Finathene XS10, The bulk flow rate (MFR) was 0.3 g / 10 min and the density was (0.950-0.9595) g / cm3. Experiments have shown that the new resins outperform all third generation resins in physical properties, exhibit excellent resistance to slow crack growth and rapid crack propagation resistance, and are the first high density materials to be more resistant than hexene copolymerized medium density polyolefin materials . The use of hexene as the comonomer instead of the traditional butene gives Finathene XS10 a more uniform extrusion behavior than typical PE100.

  (B) Solvay Polyolefins Europe
  Solvay Polyolefin Europe recently introduced the new PE100 grade for pressure tubing, Eltex TUX100, a high performance crosslinked HDPE compound. Developed specifically for tubing, this material is suitable for gas distribution tubing under special conditions for the transport of petroleum products, liquid chemicals and hot water. The Eltex TUX100 can be processed with standard equipment for the production of PE100 tubes. Solvay said the grade has more excellent properties than PE100, as follows: higher pressure strength at high temperature, better corrosion resistance and chemical resistance; high resistance to slow cracking, better resistance Rapid crack growth; Higher abrasion and scratch resistance.

  (C) South Korea's Samsung General Chemical Company
  South Korea's Samsung General Chemical Co., Ltd. successfully developed in 2005 with high strength, high pressure HDPE new materials, and achieved the PE112 international certification. The material is produced in a tandem two-reactor process whereby the HDPE produced produces a large number of tie molecules at high molar masses so that it is well-tolerated between creep resistance and slow crack resistance The balance, while still maintaining a good processing performance. Compared with the existing bimodal PE100, PE112 can withstand higher working pressure, which can reduce the wall thickness. Made of the same diameter, the same working pressure of the pipe, PE112 wall thickness than PE100 can be reduced by 10%. The melt strength of PE112 exceeds that of PE100, and extruders can be used to produce pipes with larger diameters without wall sagging. With injection molding pipe production, its processing performance and PE100 similar. With this new material can be made up to a maximum diameter of 1600mm high pressure pipe.

  (D) other companies
  Companies such as Boreali, Solvay and Fina are developing the fourth generation of PE125 resin pipe, which is crosslinked by PE, which allows PE pipes to withstand higher pressures with thinner walls. However, the cost of cross-linked PE pipe is about 5 times higher than that of the conventional PE pipe. Only when the production technology is further improved, is its cost reduced.

  Fourth, concluding remarks

  In recent years, with the government to promote the use of chemical building materials, in many areas of the application of thermoplastic pressure pipe has been rapid development. It is estimated that the growth point of domestic pipe consumption in 2007 will be mainly in the aspects of expansion of drainage pipes in residential buildings, water pipes for construction, gas pipes for city gas supply and plastic pipes for water supply in villages and towns. With the rapid development of the construction industry and water-saving projects, China's high-density polyethylene pipe market will have tremendous potential. At the same time, the production of polyethylene pipe material in our country is not homogeneous, and the specifications are not perfect. Compared with the production capacity of polyethylene pipe, the development lags behind most of the products still to be imported. Compared with foreign countries, China's development and application of high-density polyethylene pipe there is a big gap. Therefore, on the one hand, we should closely follow the trend of research and development abroad and, in light of the actual situation in our country, develop the economical and practical pressure pipe material that is suitable for our country; on the other hand, relevant departments should also increase the policy support for plastic pressure pipelines Efforts to promote the development of related industries.