Characteristics and application development of polyurethane elastomers

Thread Content

Features and Application Development of Polyurethane Elastomers Features and Application Development of Polyurethane Elastomers With the development of society and technological progress, new materials are being used more and more widely. Since the early 1980s, polyurethane elastomers have shifted from military use to dual-use applications for both military and civilian purposes, with a focus on civilian applications. As a result, the variety of products available has increased, production scales have grown, and these elastomers have come to play an increasingly important role in various sectors of the national economy as well as in people’s daily lives, including clothing, food, housing, and transportation. From a practical application perspective, let’s discuss the advantages and disadvantages of polyurethane elastomers, as well as the current status and future prospects of their application development. I. Main advantages of polyurethane elastomers 1. Excellent wear resistance. Especially under working conditions with wetting media such as water and oil, its wear resistance is often several times to dozens of times that of ordinary rubber materials. Metal materials such as steel are very hard, but they are not necessarily wear-resistant. For example, the large water pumps used in the Yellow River irrigation area experience severe wear and start leaking within a few hours due to the erosion caused by large amounts of sediment against the metal rings and protective sleeves on their moving parts; in contrast, those with polyurethane elastomers covering the rings and protective sleeves can continue to operate for 1,800 hours without any wear. Other applications of polyurethane elastomers include the rubber rollers used in rice milling machines, the sieve plates used in coal sorting, the running tracks in sports fields, the dynamic oil seals used in cranes and forklifts, as well as elevator wheels and roller skates. It should be noted here that in order to increase the friction coefficient of polyurethane elastomer components with medium to low hardness and improve their wear resistance under load, small amounts of lubricants such as aluminum disulfide, graphite, or silicone oil can be added to these polyurethane elastomers. 2. There are various processing methods, offering wide applicability. Polyurethane elastomers can be shaped using processes such as plasticization, mixing, and vulcanization, just like conventional rubbers (referring to MPU); they can also be made into liquid rubber form for casting or molding, as well as for spraying, potting, or centrifugal molding (referring to CPU). Additionally, they can be converted into granular form, and then shaped using processes such as injection, extrusion, calendering, or blow molding, just like ordinary plastics (referring to CPU). Molded or injection-molded parts can also undergo mechanical processing such as cutting, grinding, and drilling within a certain range of hardness. The diversity of processing methods makes polyurethane elastomers highly versatile, with their application areas continuing to expand. 3. Resistant to oil, ozone, aging, radiation, and low temperatures; it has good sound transmission properties, strong adhesion, and excellent biocompatibility and hemocompatibility. It is these advantages that enable polyurethane elastomers to be widely used in fields such as military industry, aerospace, acoustics, and biology. The disadvantages of ester amide elastomers: However, polyurethane elastomers are not perfect either; their main drawbacks are: 1. High internal heat generation, and average high-temperature resistance. The typical operating temperature range is from -40°C to 120°C. If long-term operation under high-frequency oscillation conditions or high-temperature conditions is required, corresponding modifications must be made to the structural design or formulation. 2. It is not resistant to highly polar solvents and strong acid-base media. At a certain temperature, alcohols and acids can cause polyurethane elastomers to swell and degrade; solvents such as chloroform, dichloromethane, methyl formamide, and trichloroethylene can cause polyurethane elastomers to swell at room temperature. Third, the applications and development of polyurethane elastomers. As mentioned above, the overall performance of polyurethane elastomers is highly excellent. In recent years, countries have been intensifying their research on application development in line with market demands, with a focus on the following areas: 1. Polyurethane elastomers for use in automobiles. The modern automotive industry is evolving toward higher performance, lower weight, greater comfort, and improved safety. Rubber-plastic composite materials will gradually replace metal materials, which opens up extremely broad prospects for the application of polyurethane elastomers. The American company Goodric has developed a second-generation TPU, commercially known as Estaloc. This product retains the properties of the first-generation TPU, using hollow glass balls as fillers: it increases the gloss by more than 15%, and can be used to manufacture automotive side panels and shock absorbers. Installing airbags in cars is a requirement of the development of the modern automotive industry, and it plays a crucial role in protecting the lives of drivers. Such airbags must possess a certain degree of strength to withstand high-speed impacts, as well as good flexibility at low temperatures; they are suitable to be made from polyurethane, with approximately 300 grams of adhesive being used per airbag. Most cars in our country still do not have airbags, so there is a high demand in the market. By leveraging the high strength and high load-bearing capacity of polyurethane elastomers, tires for medium- and low-speed heavy-duty vehicles can be manufactured, with a load-bearing capacity 7 times that of tires of the same specification made from natural rubber. In recent years, a new type of green polyurethane composite tire has been under development. It uses new and used rubber carcasses as a base, to which a high-strength, puncture-resistant polyurethane rubber tread layer of a certain thickness is applied. It is currently in the stage of mileage testing, and production is expected to begin in the near future. 2. Polyurethane elastomers for construction. Traditional asphalt felt waterproofing materials have gradually been replaced by durable and easily installed polyurethane waterproofing materials. Just 10 years ago, polyurethane paving materials were used only in official competition venues of ** grade; today, most provincial stadiums, colleges and universities, and even some primary and secondary schools use polyurethane plastic running tracks. Polyurethane elastomers that cure at room temperature are now also being used for the expansion joints of large bridges, airport runways, and highway joints ； The sleepers for high-speed railways are an ideal material; the sleepers used in the tunnels and bridges along Japan’s Shinkansen lines are made of polyurethane elastomer material. This new application makes full use of the lightweight, shock-absorbing, and weather-resistant properties of polyurethane elastomers, making it highly valuable for widespread adoption. 3. Polychloride elastomers for mines. In coal mines, as well as in metal and non-metal mines, there is a high demand for non-metallic materials that are highly wear-resistant, strong, and elastic. Over the past 10 years, many coal plants have replaced bulky metal screening plates with polyester elastic screening plates; this not only **extends the service life of the screening plates but also significantly reduces noise in the operating environment, resulting in notable energy savings and reduced consumption. Other items such as cyclones used for solid separation, wear-resistant conveyor belts with flame-retardant and antistatic properties, solid wheels for mine monorail cranes, bonding plates for coal mine shotcreting machines, oil seals on 10,000-ton electric-wheel dump trucks, and cold-mixing adhesives for high-voltage cable sheaths have also played a significant role in mine construction. Recently, there are also many wear-resistant elastic products for use in mines that await our development and promotion. 4. Polyurethane elastomers for shoes. Since Taiwanese entrepreneurs have flocked to the mainland, China’s shoe-making industry has developed rapidly. Polyurethane elastomers possess advantages such as excellent cushioning properties, light weight, wear resistance, and anti-slip characteristics. They have now become important materials used in the shoe manufacturing industry. Components such as soles, heels, toes, and insoles for various types of shoes – including golf shoes, baseball shoes, soccer shoes, skiing shoes, walking shoes, and safety shoes – are all made from polyurethane elastomers. These materials not only look good but are also comfortable and durable, while also helping to improve athletic performance. 5. Medical polyurethane elastomers. Good biocompatibility and hemocompatibility, along with the absence of various additives, are key reasons why TPU and CPU materials are used in the medical field. The medical elastomeric products that have been successfully developed include tracheal tubes, prosthetics, occlusive agents useful for family planning, materials for repairing skull defects, condoms, and so on. Their applications in the healthcare field still hold great potential. This post was last edited by QXZ-1966 on 2009-3-11 17:28.]