Polyurethane elastomer characteristics and market
With the development of society and technology, more and more widespread application of new materials, polyurethane elastomers since the early 1980s from the military into dual-use, and after the civilian-based, increasing product variety brands , increasing scale of production, the role of all sectors in the national economy and people’s basic needs in all aspects played increasingly important. Now from a practical point of view, to talk about the advantages and disadvantages of polyurethane elastomer application development status and prospects.
The main advantage of a polyurethane elastomer
1, the performance can be adjusted range. A number of physical and mechanical performance indicators can be selected and adjusted by the formulation of raw materials, changes within a certain range to meet the different requirements of users of the product properties. Such as hardness, it is often an important indicator of the product’s users, both made of polyurethane elastomer Shore A hardness of 20 or so of soft printing rollers, but also made a Shore D hardness of 70 or more rigid rolling roller, This is a general elastomeric material difficult to do. Polyurethane elastomer is a polar polymer materials composed of many segments and rigid segments of flexible chains, with the improvement and increase of the polar group density rigid segment ratio of elastomer original strength and hardness will be increased accordingly.
2, superior wear resistance. Particularly where there is water, oil wetting medium existing working conditions, the wear resistance is often several times to several times the ordinary rubber materials. Metallic materials such as steel, although very hard, but not necessarily wear, such as large pumps Yellow River irrigated areas, which flow components metal mouth ring and the protection ring after a lot of sediment erosion, does not take hundreds of hours on severely worn leak , while the use of polyurethane elastomer coated mouth ring and the protection ring 1800 consecutive run into yet little wear. Others, such as milled rice hulling machine with rubber roller, coal preparation with sieve shaker, stadium track track, dynamic oil seals crane used forklifts, elevators wheel and wheel roller skates, etc. are also polyurethane elastomer comes in. This is mentioned in point is, to improve the friction coefficient low hardness polyurethane elastomer parts, improved wear resistance under load bearing, you can add a small amount of disulfide aluminum, graphite or silicone oil in such a polyurethane elastomer, etc. lubricant.
3, processing methods and diverse, broad applicability. Polyurethane elastomer can now use the same general rubber mastication, mixing, curing molding process (refer MPU); also be made of liquid rubber, cast molding or coating, potting, centrifugal molding (referring to CPU); you can also make into pellets, and, like ordinary plastic, by injection, extrusion, calendering, blow molding and other processes (ie CPU). Molding or injection molded parts, within a certain range of hardness, but also can be cut, grinding, drilling and other machining. Processing of diversity, the applicability of the polyurethane elastomer is very extensive, applications continue to expand.
4, oil resistance, ozone resistance, aging resistance, radiation resistance, low temperature, transparent sound good, strong adhesion, excellent biocompatibility and blood compatibility. It is these advantages of polyurethane elastomer widely used in military, aerospace, acoustics, biology and other reasons.
Second, the inadequacy of ester urethane elastomers polyurethane elastomer but not perfect, its main drawback is:
1, endogenous heat, high temperature performance in general. Normal operating temperature range is -40 ~ 120 ℃ use. For long-term effects of high-frequency oscillation conditions or under high temperature conditions, it must be modified to take appropriate measures on the structural design or formula.
2, impatient polar solvent and strong acid medium. At a certain temperature, alcohols, acids, ketones cause swelling and degradation of the polyurethane elastomer, chloroform, methylene chloride, dimethylformamide, trichlorethylene and other solvents at room temperature, it will swell the polyurethane elastomer.
Third, the polyurethane elastomer applications and development
In summary, the overall performance of polyurethane elastomers are very favorable. In recent years, countries are strengthening their research application development based on market demand, the development focus in the following areas:
1, automotive polyurethane elastomer. Today’s automotive industry is developing towards high performance, low weight, comfort and safety directions. Rubber and synthetic material is gradually replaced by a metallic material, which is applied polyurethane elastomer has opened up very broad prospects. US Goodrich has developed a second generation of TPU, their business name Estaloc. The product maintains the characteristics of first-generation TPU Estaloc, and hollow glass spheres as filler, glossiness increased by over 15%, can be used to manufacture automobile side panels and shock absorption pad. Install airbags in the car, is the need for the development of the modern automobile industry, to protect the safety of the driver has a major role. This balloon must have a certain strength to withstand high-speed impact, but also has good low temperature flexibility, suitable for polyurethane production, each air bag with plastic about 300 grams. Most of our cars is not already installed airbags, great market demand. The use of high-strength polyurethane elastomers and high load carrying capacity. 7 times can be manufactured in low-speed truck vehicle tires, strength and high load carrying capacity, can be manufactured in low-speed truck vehicle tires, its carrying capacity is the same size made of natural rubber tires. In recent years, a new type of green polyurethane compound tire being studied in development, it is based on old rubber tires as a matrix of light, casting a certain thickness of the high wear-resistant polyurethane rubber surface layer of puncture resistance, and is currently in the mileage test stage, shortly after the expected investment refers to the production.
2, polyurethane elastomer construction. Traditional asphalt felt waterproof material has gradually been durable, waterproof polyurethane integral construction material substitution; stadium runway in 10 years ago, only national official venue only polyurethane surfacing materials, and now most provinces Stadium, colleges, and even some primary and secondary schools are also covered with a polyurethane plastic runway; large bridge expansion joints, caulking airport runways and highways are beginning to use room temperature curing polyurethane elastomer produced high-speed railway sleeper is ideal material, being paved through tunnels and bridges on the Japanese Shinkansen railway sleepers is the use of polyurethane elastomer material. This new application full of poly acid elastic physical light, shock absorption and good resistance to aging characteristics, good promotional value.
3, mining polyurethane elastomers. Coal, metal and non-metal materials and nonmetal mines demand for high wear resistance, high strength yet flexible large. The past 10 years, many choose coal plants with polyurethane elastic screening board to replace the heavy metal sieve, sieve not only greatly extend the service life and significantly reduced noise operating environment, energy saving effect is obvious. Others, such as for the production of solids separation cyclone, fire-retardant anti-static wear conveyor belts, mining monorail solid core wheel, coal shotcrete machine with binding plates, oil seals tons on electric wheel dump truck high-voltage cable sheath cold patch glue, also are mine construction played a significant role. There are still many mines with wear-resistant elastic products are waiting for us to develop and promote.
4, shoes with polyurethane elastomer. Since Taiwanese came to the mainland, China’s footwear industry has developed rapidly. Polyurethane elastic with good cushioning performance, lightweight, wear-resistant, non-slip, etc., the shoe industry has become an important supporting materials, golf shoes, baseball shoes, soccer shoes, ski boots, shoes, safety shoes and many shoe soles, heel, toe, insoles and other important accessories are to use polyurethane elastomer is not only beautiful, but also comfortable and durable, but also improve athletic performance.
5, medical polyurethane elastomer. Good biocompatibility, blood compatibility, no additives and is a major cause CPU TPU material obtained in the medical field applications. Has developed a successful medical elastomer products are: tracheal tube, artificial limbs, family planning use bolt blocking agent, skull defect repair material, condoms and so on, the prospect of its application in the field of health care is also very broad.
6, the new polyurethane composite sheet. Britain is developing a polyurethane composite board plywood layer called SPS system, will bring a revolution in shipbuilding. It includes two 9mm thick steel plate and are injected 40mm thick polyurethane elastomer their middle, once developed, can replace the traditional shipbuilding material used to strengthen steel, its advantages are: saving manufacturing time, save steel, reduce the hull weight , impact resistance, fatigue resistance, shock absorption, noise, heat insulation. Once the future SPS system uses composite materials to shipbuilding then, shipbuilding consumed polyurethane elastomer will be a very alarming figure.