Ultra-high molecular weight polyethylene (UHMWPE) (UHMWPE) usually refers to linear polyethylene with viscosity average molecular weight more than 1.5 million and heavy average molecular weight over 3 million. The molecular structure of UHMWPE is basically the same as that of ordinary polyethylene. But physical and mechanical properties far exceed ordinary polyethylene, such as non-toxic, light weight, low price, low water absorption, has a very good ultra-low temperature performance, especially its impact resistance, wear resistance, chemical corrosion resistance, Self-lubricity and shock energy absorption are the best of all plastics, known as "amazing plastics".
A, ultra-high molecular weight polyethylene (UHMWPE) has excellent performance in the following ten aspects:
1: high wear resistance: its wear resistance ranks first among existing plastics, 2.5 times higher than nylon 66, 3.6 times higher than polytetrafluoroethylene, 7 times higher than carbon steel and 9.0 times higher than stainless steel.
High impact resistance: its impact strength greatly exceeds the toughness of polycarbonate, is among the best among engineering plastics, and can be maintained in liquid nitrogen (- 196 ℃) environment, which other plastics do not.
3: high self-lubricity: its friction coefficient is very low (0.07x0.11), which is comparable to PTFE and is better than steel and copper when lubricated.
4: excellent chemical corrosion resistance: can resist various corrosion media and organic solvents at a certain temperature and concentration.
5: excellent impact energy absorption: at the same time its sound absorption effect is also very good.
6: excellent low temperature resistance.
7: excellent hygiene performance.
8: excellent non-absorbent.
9: excellent non-stickiness.
10: density is the smallest of all engineering plastics.
It is precisely because of the excellent performance of UHMWPE, it is in transport, agriculture, mining, chemical, machinery, construction, paper, textile, food, medical, sports and other fields.
Since the commercialization of UHMWPE resin in the late 1950s and early 1960s, UHMWPE has been used more and more widely because of its excellent performance and continuous development of molding processing technology, and its consumption has maintained the momentum of continuous growth. Before the 1980s, the world grew at an average annual rate of about 8.5%, up from 16% in the 1980s. Although the domestic production of UHMWPE resin started relatively late, but the average annual growth rate is more than 30%. The main manufacturers are Beijing Auxiliaries No.2, Wuxi Fukun Chemical Co., Ltd., Shanghai Chemical Research Institute, Qilu Petrochemical Research Institute Etc., the existing national production capacity of UHMWPE resin has exceeded 20, 000 tons. However, because of its high viscosity and low critical shear rate, the molding process of its products is very difficult. For a long time, because the domestic UHMWPE molding technology and equipment are relatively backward, and there is a big gap with the advanced countries, so far, UHMWPE products have not been put into large-scale industrial production. Limited to small batch production based on pressing-sintering or plunger roll-out molding, the production efficiency and product output are low, the product quality is poor, the production energy consumption and the product cost are very high, which not only limits our country's UHMWP. The market demand and application of E resin, Moreover, 80% of the raw materials of domestic UHMWPE resin have to be sold abroad at low price. The successful development of UHMWPE single screw continuous extrusion technology and equipment indicates that the application and processing of UHMWPE resin in China has entered a new field with high efficiency. High-yield, high-quality, low-cost industrialization continuously extruded bar, pipe, profile and other products, so as to greatly broaden the application of UHMWPE products and fully meet the growing needs of domestic market consumption. As can be seen from the above, with the scale of UHMWPE chemical industry in China The expansion of the application field of UHMWPE products and the increasing demand of market consumption in China are a difficult problem to be solved urgently in the field of chemical industry in China. After years of research, the plastic mechanical and plastic engineering research institute of Beijing Chemical Engineering University has successfully developed a special-purpose formula and an extrusion forming process for ultra-high molecular weight polyethylene special-screw extruder and ultra-high molecular weight polyethylene extrusion, and can continuously extrude various kinds of pipes, Profile and bar products. At the same time, the ultra-high molecular weight polyethylene is also developed. We use modified ultra-high molecular weight polyethylene (UHMWPE) for injection molding of various sliding parts, artificial joints and other products. The production of ultra-high molecular weight polyethylene (UHMWPE) roller is a new product which is assembled by UHMWPE pipe and metal bearing, metal shaft and plastic end cover. Rollers are widely used on retractable belt conveyor, including upper and lower rollers.
At present, the main use of cast steel roller on the market. Ultra-high molecular weight polyethylene roller retains all the excellent properties of ultra-high molecular weight polyethylene, wear resistance is 7 times as high as steel, 3 times as much as nylon, has anti-friction self-lubrication, anti-impact, noise and vibration elimination, anti-bonding, corrosion, aging resistance and so on. Widely used in metallurgical mines, coal mines, chemical industry, grain storage, building materials, ports, salt farms, electric power and other industries, is the best alternative to metal rollers. UHMWPE roller promotion and use, improve transport capacity, protect belts, reduce maintenance, In terms of energy saving and consumption reduction, the traditional metal roller has a very significant economic effect. Benefit.
B, ultra-high molecular weight polyethylene (UHMWPE) has the following advantages:
1, non-adhesion and accumulation of material
Ultra-high molecular weight polyethylene (UHMWPE) has good self-lubricating and non-adhesive properties, so it does not adhere to and accumulate materials on the surface of roller.
2. Flexible and smooth operation
The friction coefficient of UHMWPE is much lower than that of steel, so the operation of UHMWPE roller is more flexible and stable.
3, long useful life
Ultra-high molecular weight polyethylene wear resistance is 7 times as high as steel, nylon 3 times, more than all engineering plastics, known as "wear-resistant king". Moreover, the impact resistance of UHMWPE roller is very good, so it is difficult to break and break. In fact, the impact toughness test of ultra-high molecular weight polyethylene (UHMWPE) material can not be broken.
4, extended belt life
UHMWPE roller has non-adhesive, rust-free and self-lubricating properties, so it has better protection to the belt. On the other hand, the hand of the belt will not be "bitten", even if the roller does not turn, it will not damage the belt, greatly prolonging the life of the belt. In fact, UHMWPE has been used as a protective lining for belts, chains, etc.
5, low operation cost and remarkable economic benefit
UHMWPE rollers are light weight (generally only 1-3-1-2 of the same size steel roller weight), easy to install and replace, reduce labor intensity and maintenance, and can save about 16% of power consumption.
6, reduce operating noise
Ultra-high molecular weight polyethylene (UHMWPE) has good shock energy absorption and damping properties, and can effectively eliminate noise and vibration.
7, good bearing and anticorrosion properties
By means of adjusting the wall thickness of cylinder (above 7mm), supporting structure and adopting steel-plastic composite structure, UHMW-PE roller can meet the requirement of heavy load transportation.
At present, some domestic power plants have begun to promote the use of this product in small batches, the effect is remarkable. This product has been widely used in many industrial fields in Japan.
Ultra-high molecular weight polyethylene pipe can be widely used in grain processing industry, chemical industry, coal, mining, metallurgy, thermoelectricity, water conservancy and other industries, such as powder, granular fluid, solid-liquid mixture wear-resistant, corrosion-resistant transport, etc. To replace the original metal pipe or other plastic pipe. At the same time, in order to make full use of the excellent properties of UHMWPE, UHMWPE can be made into thick-walled pipes, and then cut into various bushes, mainly used to replace coal, various mines, grain processing, salt, sugar, cement sand, metallurgy, Port and other industries such as belt conveyor rollers. Because the working conditions of mine belt conveyor are very bad Inferior, the traditional use of steel, more complex structure, difficult to maintain, water, coal slime, coal slag, ore, stone and so on often enter the bearing, so that the bearing movement clearance becomes smaller or rusty, resulting in inflexible operation, or even Kaka death. Increased roller and belt wear. Its service life is generally only 3 months. The daily maintenance of belt conveyor is mainly to replace the rollers.
If these rollers are made by UHMWPE, it needs about 400000 tons per year. Because of the high wear resistance and high self-lubricity of UHMWPE, the installation and maintenance are very convenient. At the same time, it can save millions of maintenance expenses for the coal industry every year. So far, the domestic raw coal output has exceeded 1.2 billion tons, about 18 million sets of belt conveyor rollers are needed each year, which does not include the demand of other industries such as grain processing, chemical industry, fertilizer, metallurgy and marine chemical industry. Compared with the traditional steel roller, UHMWPE roller has the advantages of no maintenance, long life, light weight, and so on. The industrialization of ultra-high molecular weight polyethylene (UHMWPE) roller gradually occupied a certain market share, especially in the low speed, light load field compared with the metal roller has obvious advantages, has a very broad market prospect.
