UHMWPE has excellent chemical resistance, except for strong oxidizing acid, it can resist all kinds of corrosive media (acid, alkali, salt) and organic media (except for solvent) within one discharge temperature and concentration. It is impregnated in 80 kinds of organic solvents at 20°C and 80°C for 30d, there is no abnormal phenomenon on the appearance, and other physical properties are almost unchanged.
UHMWPE has excellent impact energy absorption, impact energy absorption value is the highest among all plastics, so the noise damping performance is very good, with excellent sound reduction.
UHMWPE has excellent low-temperature resistance, in liquid nitrogen temperature (-269 ° C) still has ductility, and therefore can be used for the nuclear industry's low-temperature parts.
UHMWPE hygienic non-toxic, in full compliance with the standards of the Japan Health Association, and recognized by the U.S. Food and Agriculture Administration and the U.S. Department of Agriculture, can be used for food contact.
UHMWPE surface and the adsorption ability is very weak, Tho anti-adhesion ability is second only to the plastic in the non-adhesion of the best 1 PTFE, so the surface of the product and other materials are not easy to stick to.
UHMWPE water absorption is very low: generally less than %, only 1% of PA66, and thus generally do not have to dry before the molding process.
The density of UHMWPE is lower than all other engineering plastics, generally lower than PTFE 56 milk than P0M 33% lower than PBTP 30%, so its products are very lightweight.
Because UHMWPE has the necessary structural characteristics for tensile orientation, it has unmatched ultra-high tensile strength, so it can be used to produce ultra-high modulus of elasticity and strength fibers by gel spinning method, and its tensile strength is as high as 3~3~, and its modulus of elasticity is as high as 100~125GPa. The specific strength of the fiber is the highest of all the fibers that have been commercialized so far, which is 4 times bigger than that of carbon fibers, 10 times bigger than that of steel wires, and 50% bigger than that of aramid fibers. It is 4 times larger than carbon fiber, 10 times larger than steel wire, and 50% larger than aramid fiber.
UHMWPE also has excellent electrical insulation properties, better environmental stress crack resistance than HDPE, better fatigue resistance than HDPE and r-ray resistance.
Applications of UHMWPE
At present, UHMWPE has been widely used in the fields of textile, paper, packaging, transportation, writing, chemical industry, mining, petroleum, construction, electricity, food, medical care, sports, etc., and has begun to enter the field of conventional weapons, ships, automobiles, etc. In the future, it will also be expanded to aerospace and atomic energy. In the future, it will be expanded to the fields of aerospace and atomic energy.
1, Wear resistance and impact resistance-oriented applications
Textile machinery
Textile machinery is the earliest application of UHMWPE in the field, as early as 1958, there are several companies with UHMWPE to prevent the manufacture of mechanical parts, such as replacing the toughness of the most durable materials produced by the buffalo skin leather knots on the loom to withstand the impact of long-term vibration of 40 ~ 180 times / min, the life of up to buffalo skin knots 5 ~ 6 times. At present, foreign applications in each loom UHMWPE parts on average about 30 pieces, such as shuttle casting, shuttle bar, gears, couplings, sweeping rod, buffer blocks, rod bushings, swing back beam and other impact wear parts.
Paper making machinery
Paper machinery is the application of UHMWPE the second industrial field, about 1960, in a wood chipper conveyor loaded for the first time on the installation of UHMWPE wear strips, the bottom plate and chain to play a good role in protecting the use of 5a basically no wear. It is estimated that the life of anti-friction strips is more than twice as long as the life of chains. UHMWPE and other wear-resistant materials such as stainless steel, maple, cast polyurethane, and laminated phenolic plastics are all used as suction tank covers, but the important thing is that the resistance of UHMWPE covers to stainless steel wire mesh on the suction tanks is much lower than that of other materials, which extends the life of expensive stainless steel dead mesh. Today, the paper industry needs UHMWPE usage accounted for 10% of the total amount, such as the use of UHMWPE manufacturing paper machine scraper, suction box cover, pressure and density parts, joints, etc.: In addition, UHMWPE can also be used to manufacture paper machinery sealing shaft, deflector, scraper, filter and other parts.
Packaging Machinery
The high wear resistance, low friction factor and non-stickiness of UHMWPE make it more suitable than some metals and other plastics in packaging machinery, and it can replace phosphor bronze and fluorine plastic. Using UHMWPE to replace modified fluoroplastics to make guide rails, slider seats for conveyor equipment, solid left plate, etc., not only greatly reduces the cost of investment in equipment, but also extends the service life by 10 to 50 times. A liquid detergent production line device on the juice star wheel, with UHMWPE instead of the original laminated thermosetting plastic, so that in the past, easy to wear, easy to scratch the bottle and easy to soften the problem solved, greatly reducing the cost of spare parts, UHMWPE manufactured timing screws, has also been used as a standard component in many bottling line. A large beer factory in the West, with UHMWPE produced a treaty length of the plate belt bottle conveyor belt, than the use of phosphor bronze made of conveyor belt durability of several times. An automobile assembly plant abroad on the conveyor line, chain-driven sprockets to make the trolley in the steel plate conveyor platform movement, due to friction between the chain and the steel plate, the chain is very easy to damage. The use of UHMWPE sheet to replace the steel plate greatly reduces wear and tear, and also reduces power consumption.
General purpose machinery
As UHMWPE has excellent wear resistance and impact resistance, it is widely used in the machinery manufacturing industry, and can be used to make all kinds of gears, cams, impellers, rollers, pulleys, bearings, axle shingles, bushings, shaft cutters,
gaskets, sealing gaskets, elastic couplings, screws and other mechanical parts.
2、Self-lubricating and non-stick based applications
Material storage and transportation
UHMWPE can be made to load coal, cement, lime, mineral powder, salt, grain and other powdery materials such as hopper, silo, chute lining, because it has excellent self-lubricating, non-adhesive, so that the above powdery materials on the storage and transportation equipment does not adhere to the phenomenon, to ensure that the stable leakage of transportation. Coal, mineral powder, grain and other hoppers used in the past stainless steel lining for box transportation, now changed to UHMWPE lining, long-term use, can reduce the phenomenon of heat, Baosteel ore hopper using UHMWPE, than the original use of metal materials to improve the service life of 10 ~ 50 times. The hopper lining made of UHMWPE is easy to construct and low cost, so the charging hopper for coal transportation in big power plants also adopts UHMWPE lining.
The coal chute in the coal mine is made of UHMWPE, and the angle of inclination can be lowered, thus increasing the mining capacity. The service life of the chute is two times longer than that of the magnesium alloy-lined chute, as 400,000 tons of coal can be transported without replacing the chute.
The service life of UHMWPE is 18 times higher than that of steel pipe and the cost is reduced to 1/25, and the service life is 3 times higher than that of nylon pipe and the cost is reduced to 1/8. When conveying, the resistance inside the pipe is 25% lower than that of metal pipe, which greatly improves the conveying efficiency.
In the lining of chutes, buckets and ore carriages, when using traditional metal materials, the materials will freeze on the metal in cold and wet weather, but not with UHMWPE, which greatly reduces the unloading time. After lining a layer of UHMWPE sheet on the self-unloading hopper of bulk carrier, the average unloading time is reduced from 16~20h to 8h.
Agricultural, construction machinery UHMWPE self-lubricating excellent, mud on its surface and easy to slide, without adhesion, and its impact resistance, wear resistance is excellent, suitable for the production of agricultural and construction machinery parts. For example, the sliding plate of combine harvester, the outer liner of plow, the scraper of excavator, the inner liner of bucket of excavator, the inner liner of dump truck, etc., which can greatly improve the working efficiency and reduce the energy consumption. Sporting Goods Using UHMWPE self-lubricating and abrasion resistance and cold resistance, can be used for ice skating, ski base plate, Europe and the United States mainly use UHMWPE blood with UHMWPE covered ski trails (layer thickness of 20mm), skateboards can reach the maximum speed of 110kWh.
3、Application of corrosion resistance and non-absorbent water.
UHMWPE has excellent chemical stability and non-hygroscopicity, so it can be used as paving materials for various solution storage equipments and large-scale packaging containers, such as floats, receiving tanks, gasoline tanks, pesticide containers, and water-returning containers for solar energy equipments, etc. This is also the main application of UHMWPE at present. This is also one of the most widely used fields of UHMWPE.
UHMWPE containers have excellent falling impact strength. If the container is filled with 20kg of water and dropped from high altitude onto a lOnrni thick iron plate, the destructive height of ordinary polyethylene containers is only 9M, while that of UHMWPE containers can be as high as more than 15M.
4, Hygiene and non-toxicity-oriented applications
Food and beverage industry
UHMWPE has non-toxicity, water resistance and non-adhesive properties required by the food industry. It is designated as a material that can be used in direct contact with food. UHMWPE is used for meat processing plants, cutting boards, meat chopping boards, slaughterhouse boards, and conveying lines for beer,
Cooler drinks, and condiments. When conveying goods, it can prevent the breakage of bottles, etc., reduce noise, reduce wear and tear of conveyor belts and conveyor screws, etc., and reduce power loss. It can also be used to manufacture meat, milk, and candies, preserves, and parts of packaged food production equipment. Medical UHMWPE has excellent physiological inertness and physiological adaptability.
Approved by the U.S. Food and Drug Administration, the Department of Agriculture, can be used in the field of medicine several contact with the human body, such as as heart valves, orthopedic parts, artificial joints and Xiao Yu implants and other clinical use, is the ideal medical polymer materials. There are UHMWPE made of carpal socket and metal femoral bamboo composed of artificial pre-joint, wear resistance and safety than PTFE is more excellent. At present, hundreds of thousands of people in the world have received such artificial joint replacement.
5, Other properties of the application
Low-temperature resistance application UHMWPE has excellent low-temperature resistance, can be used in a variety of refrigeration machinery, and can be used as a nuclear industry of low-temperature resistance, and can be used as a nuclear industry of low-temperature resistance.
UHMWPE has excellent low temperature resistance and can be used in all kinds of refrigeration machinery, and can be used as low temperature resistant parts in the nuclear industry, and is a more ideal insulating material in the field of low-temperature superconductivity.UHMWPE has an excellent shielding effect of radiation, so it can be used as a shielding plate of atomic energy power station. UHMWPE has good electrical insulation properties, especially low dielectric loss tangent, and can be used to manufacture electroplating tanks, reels, insulators working in high and ultra-high frequency range, insulating trailing frames, cable ducts, short circuit breakers, cable terminals and other electrical devices.
Disadvantages
Compared with other engineering plastics, the heat resistance, stiffness and hardness of UHMWPE is low, but it can be improved by "filling" and "cross-linking" and other methods: from the point of view of heat resistance, the melting point of UHMWPE (136°C) is more or less the same as that of ordinary polyethylene, but due to the high molecular weight of UHMWPE, the melting point of UHMWPE is about the same as that of ordinary polyethylene. In terms of heat resistance, the melting point (136°C) of UHMWPE is more or less the same as that of ordinary polyethylene. The melting viscosity is high, so it is difficult to process.
