Electromagnetic heating roll
作者：管理员 时间：2020-06-04 08:55 来源：未知
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What's aramid?
Nomex is a kind of aramid, which is phthalylphenylenediamine. It is a new high-tech synthetic fiber with ultra-high strength, high modulus and high temperature resistance, acid resistance, alkali resistance, light weight, insulation, and anti-aging., life cycle long and other excellent performance, Widely used in composite materials, bulletproof products, building materials, special protective clothing, electronic equipment and other fields.
Basic information
Chinese name Fang Lun
All referred to as polyphthalylphenylenediamine
Sex has good insulation and anti-aging properties
Fang Lun Introduction
The full name of aramid is "polyphthalylphenylenediamine", and the English name is Aramid fiber.(The product name of Emperor Aron DuPont is called Kevlar). It is a new high-tech synthetic fiber with super high strength and high modulus. High temperature, acid resistance, alkali resistance, light weight and other excellent performance, Its strength is 5 to 6 times that of the steel wire, the modulus is 2 to 3 times that of the steel wire or glass fiber, the toughness is 2 times that of the steel wire, and the weight is only about 1/5 of the steel wire. At a temperature of 560 degrees, it does not decompose and does not melt. It has good insulation and anti-aging properties and has a long life cycle. The discovery of Fang Lun is considered to be a very important historical process in the material world.
Production background
Since asbestos has been recognized as a strong carcinogen, asbestos and its products have been banned in many developed countries around the world. The United States, Japan and other countries have successfully developed various series of non-asbestos gasket materials, and the products have now been introduced to the world market. With the continuous integration with the international environment. Non-asbestos sealing materials are being recognized and received by various industrial sectors in the country. For environmental protection and safety of production, the industrial application of non-asbestos gaskets will become more and more widespread. Sealed gaskets with non-asbestos fibre as reinforcement and rubber as elastic matrix are usually referred to as non-asbestos fibre rubber gaskets, or asbestos-free gaskets and asbestos substitute gaskets. Its main reinforcing materials are asbestos fibers, inorganic fibers, carbon/graphite fibers, etc..
Status of development
The aramid fiber was born in the late 1960s and was initially known as a material for the development of the universe and an important strategic material. After the end of the Cold War, Fang Lun was used in the civilian field as a high-technology fiber material and gradually became known. The full name of aramid is "aromatic polyamide fiber" and is a new type of special-purpose synthetic fiber. There are two most useful varieties of aramid: First, the interposition aramid fiber with serrated molecular chains, which is called aramid 1313 in China; The first is that the molecular chain is arranged in a linear order of aramid fibers, which is called aramid 1414 in China.
From a global perspective, the global interposition aramid(1313) production capacity of 32,000 tons, supply and demand are basically balanced. In terms of domestic supply and demand, China's demand for inter-position aramid is about 10,000 tons, while the total domestic production capacity is 8,600 tons, and the production capacity is obviously insufficient. As the leader of the domestic market, Taihe Xincai occupies more than 60 % of the market share, and the gross profit margin is basically stable at more than 35 %. The global market for aramid is about 65,000 tons. In 2011, the global demand for aramid was about 53,000 tons. The world's main manufacturers of Fang Lun are Meiguodubang and the Japanese Emperor, with a production capacity of 28,600 tons and 28,450 tons, respectively, almost monopolizing the international market. China's annual demand for aramid is more than 5,000 tons, all dependent on imports, and the price of the item is 200,000 yuan per ton.
With the Environmental Protection campaign against the use of asbestos in Europe and the United States, aramid pulp fiber has been rapidly developed, gradually replacing asbestos as the main material for brake sheets, clutch sheets, and sealing pads. In addition, it has also been widely used in other industrial fields, such as optical fiber protection, high-temperature filter bags, automotive rubber tubes, tires, sound wave cloth, power conveyor belts, transport belts, transfer printing blankets, rubber shoes soles, etc.; In the field of individual protection, Fang Lun can be made into body armor, bulletproof helmets, bulletproof armor, etc., fire uniforms, fire masks, military and police uniforms, and anti-cutting gloves; In the civilian field, Fang Lun can be made into flame retardant interior and fabrics for aircraft, automobiles, and high-speed rail. It can be made into fire blankets, escape ropes, flame retardant curtains, bed covers, pajamas, tablecloths, aprons, and microwave gloves. Fang Lun can also be made into Fang Lun paper for insulation of motors, Transformers, and electronic appliances. It can also be further processed into Honeycomb structure materials for secondary acceptance of aircraft, yachts, high-speed rail, and electric vehicles.
Fang Lun characteristics
1, good mechanical characteristics
The interposition aramid is a flexible polymer with a fracture strength higher than that of ordinary polyester, cotton, nylon, etc.. It has a large elongation rate, a soft feel, and good spinability. It can be produced into short fibers and filaments of different textures and lengths., In general textile machinery made of different yarns woven into fabrics, non-woven fabric, after finishing, to meet the requirements of different fields of protective clothing.
2, excellent flame retardant, heat resistance
The limit oxygen index(LOI) of the interposition aramid is greater than 28, so it will not continue to burn when it leaves the flame. The flame-retardant properties of Newsda ® are determined by its own chemical structure and are therefore a permanent flame-retardant fiber that does not reduce or lose flame-retardant properties due to use time and washing times. Newsda ® has a good thermal stability, can be used continuously at 205 °C, and can still maintain high strength at high temperatures greater than 205 °C. Newsda ® Interposition aramid has a higher decomposition temperature, and it does not melt or melt at high temperatures, and carbonization begins when the temperature is greater than 370 °C.
3, stable chemical properties
The interposition aramid has excellent resistance to most chemical substances, can withstand most high concentrations of inorganic acids, and has good alkali resistance at room temperature.
4, radiation resistance
The radiation resistance of interposition aramid is very good. For example, its intensity remains unchanged under prolonged irradiation of 1.2 × 10-2 w/in2 ultraviolet rays and 1.72 × 108 rads gamma rays.
5, durability
The excellent friction-resistant and chemical-resistant properties of the interposition aramid, after 100 washes, the tearing power of the fabric processed with the interposition aramid in Newstad ® can still reach more than 85 % of the original strength.
The temperature resistance of the paratonal aramid is higher than that of the interposition aramid, and the continuous temperature range is -196 °C ~ 204 °C. It does not decompose or melt at a high temperature of 560 °C. The most significant characteristics of the para-aramid are high strength and high modulus, and its strength is greater than 25 g/dan, which is 5 to 6 times that of high-quality steel, 3 times that of glass fiber, and 2 times that of high-strength nylon industrial silk; The modulus is 2 to 3 times that of high-quality steel or glass fiber and 10 times that of high-strength nylon industrial wire.
Aryl fiber pulp is obtained by surface primary fiber treatment. Its unique surface structure greatly improves the adhesion force of the mixture and is therefore suitable for application as a reinforced fiber in friction and sealing products.
The hexagonal special fiber -- Fanglun 1414 pulp, light yellow flock-like, plush, its rich feathers, high strength, good dimensional stability, no brittleness, high temperature resistance, corrosion resistance, toughness, small shrinkage rate, good wear resistance, large surface area, It can be well combined with other substances and is a reinforcement material with a return rate of 8 %, an average length of 2-2 .5 mm and a surface area of 8 M2 / G. It is used as a gasket enhancement material, has a good rebound performance and sealing performance, has no harm to human health and the environment, and can be used as a seal for Yushui, oil, hydrocarbons, and medium strength acids and bases. The fabricated gasket has excellent sealing performance and creep relaxation resistance.
It turns out that it is usually only necessary to add less than 10 % of the pulp to obtain a product with a strength equivalent to 50-60 % asbestos fibre reinforced products. Manufactured products such as friction enhancement and sealing materials can be used as substitutes for asbestos for friction sealing materials, high-performance heat-resistant insulating paper and reinforced composite materials.
Aramid classification
The aramid is mainly divided into two types, the p-aramides fiber(PPTA) and the interposition aramides fiber(PMIA).
In the field of aramid fiber production, the development of aramid fiber is the fastest, and production capacity is mainly concentrated in Japan, the United States, and Europe. Such as Meiguodubang's Kevlar fiber, Japanese Emperor Company's Twaron, Techinora fiber, Yantai Tai and Xincai's Taparan(Taipulong) fiber and so on. Among them, the production capacity of Meiguodubang and the Japanese emperor is about 30,000 tons, and they are in a monopoly position in the market for Fang Lun. Yantai Taihe Xincai realized the commercialization of the position of Fang Lun in 2011 and took the lead in the commercialization of the domestic position of Fang Lun.
The varieties of aromamide fibers are Meiguodubang's Nomex, Yantai Tai and Tametar's Tametar, and Conex of the Japanese emperor. Meiguodubang and Yantai Taihe Xincai are the main participants in the global competition for aramid. Both can produce industrial white and short fiber, dyeing short fiber, colored wire, filament, and aramid paper for clothing. The performance is relatively close, and the degree of differentiation is also comparable. Extensive competition has been launched in the fields of environmental protection, safety protection, industry, electronic appliances, and composite materials.
Due to foreign technology blockade and other reasons, China's production and application of aramid started late. In 2004, Yantai spandex(now renamed Taihe Xincai) achieved the industrialization of interposition aramid, and gradually developed into the world's second largest interposition aramid supplier, which greatly promoted the application and development of aramid in the domestic market; In 2011, Taihe Xincai realized the commercialization of the position of Fang Lun, and it took the lead in the commercialization of domestic position of Fang Lun. Fang Lun has been included in the "National Catalogue of High-tech Products for Encouraging Development" and the "Twelfth Five-Year Plan for the Development of Emerging Industries", and the pace of development will be gradually accelerated in the coming years.
Since the late 1960s, a variety of aramid have been introduced and industrialized. There are many kinds of aramid, and there are also many ways to divide it.
The first naming method is divided into two types, the antiposition aramid and the interposition aramid and the adjacent aramid. The monomers of the p-aramid are p-terephthalic acid and p-phenylenediamine. The functional groups on the monomers are in alignment. The polymerized chain segments are relatively regular, with good high temperature resistance, strength, and high modulus. The monomers of the interposition aramid are diphthalic acid and diphenylenediamine. The functional groups on the monomer are interpositional. The polymerized chain segments are serrated and resistant to high temperatures, but the strength modulus is slightly lower. The monomers of o-aramid are phthalic acid and phthalenediamine, and the functional groups on the monomer are Ortho positions.
The second naming method is also divided according to the structure. If the alignment is the 14 positions on the benzene ring, the interposition is the 13 positions on the benzene ring. For example, the aramid 14 is the 1 and 4 positions on the benzene ring of p-amino acid. connection, Fang Lun 1414 is the former position of Fang Lun, and Fang Lun 1313 is the previous position of Fang Lun.
The third naming method is based on the number of species of polymeric monomers. As mentioned above, Fang Lun 14 is also called Fang Lun I type, and Fang Lun 1414 and Fang Lun 1313 is also called Fang Lun II type. When a third monomer such as 4 is added to common structures such as terephthalic acid and p-phenylenediamine, terephthalic acid and m-phenylenediamine, Aramid obtained from 4 '-diaminoether, 5(6)-amino-2-(4-aminophenyl) benzimidazole can be called aramid III type. When the third unit monomer is a heterocyclic structure, it is often referred to as heterocyclic aramid.
Fang Lun use
The aramid fiber is an important defense military material. In order to meet the needs of modern warfare, the body armor of developed countries such as the United States and Britain is aramid material, and the lightweight weight of aramid body armor and helmets effectively improves the rapid response of the military. Ability and lethality. In the Gulf War, the United States and France used a large number of aramid composites. In addition to military applications, it has now been widely used as a high-technology fiber material in various aspects of the national economy such as aerospace, electromechanical, construction, automobiles, and sporting goods. In aviation and aerospace, Fanglun has a high strength due to its light quality and has saved a large amount of power fuel. According to foreign data, each kilogram of weight reduced during the launch of the spacecraft means a reduction of 1 million US dollars. cost. In addition, the rapid development of technology is opening up more new civil space for Fang Lun. According to reports, Fanglun products account for about 7 to 8 % of body armor, helmets, etc., and aerospace materials and sports materials account for about 40 %; About 20 % of Tyre skeleton materials, conveyor belt materials, etc., and about 13 % of high-strength ropes. The tire industry has also begun to use a large number of aramid cords to reduce weight and reduce rolling resistance.
