With the development of society and advancement of technology, the application of new materials has become more and more widespread. Polyurethane elastomers have changed from military to military and civilian use since the early 1980s, and after the main use of civilian products, the variety of products has increased. The increasing scale of production has played an increasingly important role in various sectors of the national economy and people's clothing, food, housing and transportation. This article intends to start from the practical application point of view, talk about the advantages and disadvantages of polyurethane elastomers and its application development status and prospects.
First, the main advantages of polyurethane elastomer
1, the performance of the adjustable range. Many physical and mechanical performance indicators can be changed within a certain range through the selection of raw materials and the adjustment of formulas, so as to meet the different requirements of users on product performance. For example, the hardness is often an important indicator of the user's product. The polyurethane elastomer can be made into a soft printing roller with a Shore A hardness of about 20, and can also be made into a hard rolling roller with a Shore D hardness of 70 or more. This is difficult for general elastomeric materials. Polyurethane elastomer is a polar polymer material composed of many soft segments and rigid segments. As the proportion of rigid segments increases and the density of polar groups increases, the original strength and hardness of the elastomer will increase accordingly.
2, superior wear resistance. Especially in the presence of water, oil and other wetting media working conditions, the wear resistance is often several times to dozens of times the ordinary rubber material. Although the metal materials such as steel are hard, they are not necessarily wear-resistant. For example, the large-scale water pump in the Yellow River irrigation area has a large amount of sediment and the metal ring and the protection ring of the flow-through parts can not be worn for hundreds of hours. , while the use of polyurethane elastomer coated ring and protective ring is continuously running 1800 small still not worn. Other husking machine rollers such as rice milling, vibrating screen plates for coal preparation, track racetracks for sports grounds, dynamic oil seals for crane forklifts, elevator wheels, and roller skate wheels are also polyurethane elastomers. The place of use. The point that needs to be mentioned here is that in order to improve the coefficient of friction of the low-to-medium-hardness polyurethane elastomer parts and to improve the wear resistance under load, a small amount of aluminum disulfide, graphite or silicone oil may be added to such polyurethane elastomer. Lubricant.
3, a variety of processing methods, a wide range of applicability. Polyurethane elastomers can be plasticized, compounded, and vulcanized (MPU) in the same way as general-purpose rubbers; they can also be made into liquid rubbers, injection molded or sprayed, potted, and centrifuged (referred to as CPUs); The pellets, like ordinary plastics, are formed by injection, extrusion, calendering, blow molding, etc. (referring to the CPU). Molded or injection molded parts can also be machined for cutting, grinding, drilling, etc. within a certain hardness range. Due to the diversity of processing, polyurethane elastomers have a wide range of applicability, and their application fields are continuously expanding.
4, oil resistance, ozone resistance, anti-aging, radiation resistance, low temperature resistance, good sound transmission, strong adhesion, excellent biocompatibility and blood compatibility. These advantages are the reasons why polyurethane elastomers are widely used in military, aerospace, acoustics, and biology.
Second, the shortcomings of ester urethane elastomer
However, polyurethane elastomers are not perfect, but their main disadvantages are:
1, endogenous heat, high temperature performance in general. Normal use temperature range is -40~120°C. If long-term operation under high-frequency oscillation conditions or high-temperature conditions is required, corresponding modification measures must be taken in the structure design or formulation.
2, not strong polar solvents and strong acid and alkali medium. At a certain temperature, alcohols, acids, and ketones will swell and degrade the polyurethane elastomer. The solvents such as chloroform, methylene chloride, dimethylformamide, and trichloroethylene will swell the polyurethane elastomer at room temperature.
Third, the application and development of polyurethane elastomer
In summary, the overall performance of polyurethane elastomers is extremely advantageous. In recent years, all countries have been strengthening their application development research based on market demand. The development focuses on the following aspects:
1. Automotive polyurethane elastomers. The current automotive industry is moving toward high performance, low weight, comfort and safety. Rubber and plastic synthetic materials are gradually replacing metal materials, which opens up a very broad prospect for the application of polyurethane elastomers. The United States Goodrich Corporation has developed a second-generation TPU whose business name is Estaloc. This product maintains the characteristics of the first generation of TPU Estaloc, and uses hollow glass balls as fillers to increase the gloss by more than 15%. It can be used to manufacture automotive side panels and cushions. The installation of airbags in automobiles is a requirement for the development of the modern automobile industry and plays a significant role in protecting the life safety of drivers. This airbag must have a certain strength to withstand high-speed impact, but also have good low-temperature flexibility, suitable for polyurethane production, each airbag with about 300 grams of glue. Most air-conditioners in China are not equipped with airbags. The market demand is large. Utilize polyurethane elastomers for high strength and high load carrying capacity. It can manufacture tires for medium and low-speed trucks with high strength and high load-bearing capacity. It can manufacture tires for medium and low-speed trucks, and its carrying capacity is 7 times that of tires of the same specifications made of natural rubber. In recent years, a new type of green polyurethane compound tire is under research and development. It is based on old and new rubber light tires as a base body and is cast with a certain thickness of a highly wear-resistant, puncture-resistant polyurethane rubber surface layer, which is currently in the mileage test. In the near future, it is expected to invest in production.
2. Building polyurethane elastomers. Traditional asphalt felt waterproof material has gradually been replaced by a durable, waterproof polyurethane construction material; the track of the stadium only used polyurethane pavement material only at the national level official competition venue 10 years ago. Nowadays, most of the provincial and municipal stadiums, Polytechnic colleges, and even some elementary and middle schools, have put polyurethane plastic tracks on them; expansion joints of large bridges, airfield runways, and highway joints have also begun to use room temperature-curing polyurethane elastomers to make sleepers for high-speed railways. It is an ideal material. Polyurethane elastomer materials are used for the sleepers on the tunnels and bridges that pass through the Shinkansen railway in Japan. This new application gives full play to the characteristics of light weight, good shock absorption, and aging resistance of the polychloric acid elastomer, which is well worth popularizing.
3, polyurethane polyurethane elastomers. Coal mines, metals, and non-metal mines are in great demand for highly wear-resistant, high-strength yet flexible non-metallic materials. In the past 10 years, many selected coal plants have replaced the bulky metal sieve plates with polyurethane elastic screening plates, which not only greatly prolongs the service life of the screen plates, but also significantly reduces the noise in the operating environment, resulting in significant energy saving and consumption reducing effects. Others such as cyclone for solid separation, flame-retardant antistatic wear-resisting conveyor belt, solid core wheel for mine monorail crane, joint board for coal mine spraying machine, oil seal ring on 10,000 tons electric wheel dump truck High-pressure cable jackets, such as cold glue, have also played a significant role in mine construction. There are still many wear-resistant elastic products for mines that are waiting for us to develop and promote them.
4. Polyurethane elastomer for shoes. Since Taiwanese businessmen came to the mainland one after another, the footwear industry in China has developed rapidly. Polyurethane elasticity has the advantages of good cushioning performance, light weight, wear resistance, non-slip, etc. Now it has become an important supporting material in the shoe industry. Golf shoes, baseball shoes, soccer shoes, ski shoes, travel shoes, safety shoes Many shoes, such as soles, heels, toes, insoles and other important accessories are made of polyurethane elastomer, not only beautiful, but also comfortable and durable, but also improve sports performance.
5, medical polyurethane elastomer. Good biocompatibility, blood compatibility, and various additives are important reasons why TPU and CPU materials are used in the medical field. Medical elastomer products that have been successfully developed include: tracheal tubes, artificial limbs, plugging agents for birth control, skull defect repair materials, condoms, etc., and their application prospects in the field of medical care are still very broad.
6, new polyurethane composite sheet. The United Kingdom is developing a polyurethane composite sheet called the SPS plywood system that will revolutionize the shipbuilding industry. It consists of two layers of 9mm thick steel plate and 40mm thick polyurethane elastomer injected into them. Once successfully developed, it can replace the reinforced steel plate material used in the traditional shipbuilding industry. Its advantages are: saving manufacturing time, saving steel plate, and reducing the weight of the hull , impact resistance, fatigue resistance, shock absorption, noise reduction, heat insulation. Once the composite material of the SPS system is used for shipbuilding in the future, the polyurethane elastomer consumed by the shipbuilding industry will be an astonishing figure.
First, the main advantages of polyurethane elastomer
1, the performance of the adjustable range. Many physical and mechanical performance indicators can be changed within a certain range through the selection of raw materials and the adjustment of formulas, so as to meet the different requirements of users on product performance. For example, the hardness is often an important indicator of the user's product. The polyurethane elastomer can be made into a soft printing roller with a Shore A hardness of about 20, and can also be made into a hard rolling roller with a Shore D hardness of 70 or more. This is difficult for general elastomeric materials. Polyurethane elastomer is a polar polymer material composed of many soft segments and rigid segments. As the proportion of rigid segments increases and the density of polar groups increases, the original strength and hardness of the elastomer will increase accordingly.
2, superior wear resistance. Especially in the presence of water, oil and other wetting media working conditions, the wear resistance is often several times to dozens of times the ordinary rubber material. Although the metal materials such as steel are hard, they are not necessarily wear-resistant. For example, the large-scale water pump in the Yellow River irrigation area has a large amount of sediment and the metal ring and the protection ring of the flow-through parts can not be worn for hundreds of hours. , while the use of polyurethane elastomer coated ring and protective ring is continuously running 1800 small still not worn. Other husking machine rollers such as rice milling, vibrating screen plates for coal preparation, track racetracks for sports grounds, dynamic oil seals for crane forklifts, elevator wheels, and roller skate wheels are also polyurethane elastomers. The place of use. The point that needs to be mentioned here is that in order to improve the coefficient of friction of the low-to-medium-hardness polyurethane elastomer parts and to improve the wear resistance under load, a small amount of aluminum disulfide, graphite or silicone oil may be added to such polyurethane elastomer. Lubricant.
3, a variety of processing methods, a wide range of applicability. Polyurethane elastomers can be plasticized, compounded, and vulcanized (MPU) in the same way as general-purpose rubbers; they can also be made into liquid rubbers, injection molded or sprayed, potted, and centrifuged (referred to as CPUs); The pellets, like ordinary plastics, are formed by injection, extrusion, calendering, blow molding, etc. (referring to the CPU). Molded or injection molded parts can also be machined for cutting, grinding, drilling, etc. within a certain hardness range. Due to the diversity of processing, polyurethane elastomers have a wide range of applicability, and their application fields are continuously expanding.
4, oil resistance, ozone resistance, anti-aging, radiation resistance, low temperature resistance, good sound transmission, strong adhesion, excellent biocompatibility and blood compatibility. These advantages are the reasons why polyurethane elastomers are widely used in military, aerospace, acoustics, and biology.
Second, the shortcomings of ester urethane elastomer
However, polyurethane elastomers are not perfect, but their main disadvantages are:
1, endogenous heat, high temperature performance in general. Normal use temperature range is -40~120°C. If long-term operation under high-frequency oscillation conditions or high-temperature conditions is required, corresponding modification measures must be taken in the structure design or formulation.
2, not strong polar solvents and strong acid and alkali medium. At a certain temperature, alcohols, acids, and ketones will swell and degrade the polyurethane elastomer. The solvents such as chloroform, methylene chloride, dimethylformamide, and trichloroethylene will swell the polyurethane elastomer at room temperature.
Third, the application and development of polyurethane elastomer
In summary, the overall performance of polyurethane elastomers is extremely advantageous. In recent years, all countries have been strengthening their application development research based on market demand. The development focuses on the following aspects:
1. Automotive polyurethane elastomers. The current automotive industry is moving toward high performance, low weight, comfort and safety. Rubber and plastic synthetic materials are gradually replacing metal materials, which opens up a very broad prospect for the application of polyurethane elastomers. The United States Goodrich Corporation has developed a second-generation TPU whose business name is Estaloc. This product maintains the characteristics of the first generation of TPU Estaloc, and uses hollow glass balls as fillers to increase the gloss by more than 15%. It can be used to manufacture automotive side panels and cushions. The installation of airbags in automobiles is a requirement for the development of the modern automobile industry and plays a significant role in protecting the life safety of drivers. This airbag must have a certain strength to withstand high-speed impact, but also have good low-temperature flexibility, suitable for polyurethane production, each airbag with about 300 grams of glue. Most air-conditioners in China are not equipped with airbags. The market demand is large. Utilize polyurethane elastomers for high strength and high load carrying capacity. It can manufacture tires for medium and low-speed trucks with high strength and high load-bearing capacity. It can manufacture tires for medium and low-speed trucks, and its carrying capacity is 7 times that of tires of the same specifications made of natural rubber. In recent years, a new type of green polyurethane compound tire is under research and development. It is based on old and new rubber light tires as a base body and is cast with a certain thickness of a highly wear-resistant, puncture-resistant polyurethane rubber surface layer, which is currently in the mileage test. In the near future, it is expected to invest in production.
2. Building polyurethane elastomers. Traditional asphalt felt waterproof material has gradually been replaced by a durable, waterproof polyurethane construction material; the track of the stadium only used polyurethane pavement material only at the national level official competition venue 10 years ago. Nowadays, most of the provincial and municipal stadiums, Polytechnic colleges, and even some elementary and middle schools, have put polyurethane plastic tracks on them; expansion joints of large bridges, airfield runways, and highway joints have also begun to use room temperature-curing polyurethane elastomers to make sleepers for high-speed railways. It is an ideal material. Polyurethane elastomer materials are used for the sleepers on the tunnels and bridges that pass through the Shinkansen railway in Japan. This new application gives full play to the characteristics of light weight, good shock absorption, and aging resistance of the polychloric acid elastomer, which is well worth popularizing.
3, polyurethane polyurethane elastomers. Coal mines, metals, and non-metal mines are in great demand for highly wear-resistant, high-strength yet flexible non-metallic materials. In the past 10 years, many selected coal plants have replaced the bulky metal sieve plates with polyurethane elastic screening plates, which not only greatly prolongs the service life of the screen plates, but also significantly reduces the noise in the operating environment, resulting in significant energy saving and consumption reducing effects. Others such as cyclone for solid separation, flame-retardant antistatic wear-resisting conveyor belt, solid core wheel for mine monorail crane, joint board for coal mine spraying machine, oil seal ring on 10,000 tons electric wheel dump truck High-pressure cable jackets, such as cold glue, have also played a significant role in mine construction. There are still many wear-resistant elastic products for mines that are waiting for us to develop and promote them.
4. Polyurethane elastomer for shoes. Since Taiwanese businessmen came to the mainland one after another, the footwear industry in China has developed rapidly. Polyurethane elasticity has the advantages of good cushioning performance, light weight, wear resistance, non-slip, etc. Now it has become an important supporting material in the shoe industry. Golf shoes, baseball shoes, soccer shoes, ski shoes, travel shoes, safety shoes Many shoes, such as soles, heels, toes, insoles and other important accessories are made of polyurethane elastomer, not only beautiful, but also comfortable and durable, but also improve sports performance.
5, medical polyurethane elastomer. Good biocompatibility, blood compatibility, and various additives are important reasons why TPU and CPU materials are used in the medical field. Medical elastomer products that have been successfully developed include: tracheal tubes, artificial limbs, plugging agents for birth control, skull defect repair materials, condoms, etc., and their application prospects in the field of medical care are still very broad.
6, new polyurethane composite sheet. The United Kingdom is developing a polyurethane composite sheet called the SPS plywood system that will revolutionize the shipbuilding industry. It consists of two layers of 9mm thick steel plate and 40mm thick polyurethane elastomer injected into them. Once successfully developed, it can replace the reinforced steel plate material used in the traditional shipbuilding industry. Its advantages are: saving manufacturing time, saving steel plate, and reducing the weight of the hull , impact resistance, fatigue resistance, shock absorption, noise reduction, heat insulation. Once the composite material of the SPS system is used for shipbuilding in the future, the polyurethane elastomer consumed by the shipbuilding industry will be an astonishing figure.