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Have you ever heard of the mysterious "golden silk"? It is a high-tech fiber, golden in color and expensive, so it is called "golden silk". It has ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, light weight and excellent performance. People figuratively compare it to "bullets can't be hit, fire can't burn", the name of this fiber is para-aramid fiber.

Aramid fiber, carbon fiber and ultra-high molecular weight polyethylene fiber are called the three high-performance fibers, which are widely used in national defense and civil industries, and are strategic materials for strengthening the country and the army. The products are mainly used in the fields of optical fiber and cable, cable webbing, skeleton materials, composite materials, friction sealing materials, textile and bulletproof protection, etc. The standard is bulletproof vests.

The bulletproof vest made of aramid fiber weighs only 1.5kg, bears and disperses the energy of bullets and shrapnel several times higher than that of steel plate, and can resist continuous firing of light machine guns. As a "pyramid" in the field of fiber materials, my country's high-performance fiber industry started late, and there is a big gap between the technical level and large-scale production capacity of developed countries. The production technology of high-performance fibers has been blocked by western countries in the past. With the development of China's national defense industry and national economy, the demand for high-performance fibers will increase. Internationally, the price of products is rising, and the application of domestic high-performance fibers in national defense and special fields is also subject to foreign supply. Therefore, vigorously developing the high-performance fiber industry, breaking foreign blockades and monopolies, and further enhancing my country's military equipment strength and industrial upgrading of the national economy have become a main direction for my country's chemical fiber industry to promote independent innovation, transformation and upgrading.

After 16 years, Sinopec has broken through key core technologies such as polymerization, spinning, and engineering amplification, and formed a complete set of para-aramid technology with independent intellectual property rights, which is of great significance to the development of my country's para-aramid industry. This achievement has broken through the foreign technical blockade, filled the domestic gap, and overcome the problems that many domestic research teams have been unable to attack for a long time. This paper will introduce the production and application of para-aramid in the world and the development trend of para-aramid in China in the future, and put forward some suggestions for the industrial development of para-aramid in China.

Research and development of 1. para-aramid

The discovery of para-aramid and subsequent application development are inseparable from DuPont. As early as 1945, with the commercialization of nylon fiber and the development of polyester fiber, DuPont's leadership formulated a long-term development plan, hoping to develop a kind of fiber with ultra-high strength and high temperature resistance in the subsequent production. In the 1960 s, DuPont's research on the improvement of low-temperature solution polymerization method and the promotion of insoluble polymer dissolution process by inorganic salt solution laid the foundation for the birth of aramid fiber. Subsequently, in 1972, DuPont solved the problem of para-aramid fiber spinning, thus introducing commercial para-aramid fiber and naming it Kelvar.

The research and development of para-aramid in various countries is not far behind, and similar products have been launched one after another. Japan's Teijin Company began to produce its own para-aramid in 1972 and named it Technora. The trade name of para-aramid introduced by Akzo Nobel Company of the Netherlands in 1986 was Twaron. South Korea's Kelon Company began research and development in 1979 and realized industrial production in 2005. Russia built a production line as early as 1985 under the trade name Terlon, but later turned to heterocyclic aramid. Its main models are Armos, SVM and Rusar.

The research of para-aramid fiber in my country began in 1972. In the following 20 years, it has experienced several stages such as laboratory research, small test and pilot test, and has been listed as a national major scientific and technological project and a national "863" plan. A series of scientific research results have been achieved, but due to many reasons, industrialization has not been achieved. In recent years, Taihe New Materials, Zhonglan Chenguang and Ping Coal Shenma and other companies in the field of aramid continued to overcome difficulties, to the market launched a number of industrial products, but the performance and production capacity of the aramid compared to the leading level of foreign countries still some gap. In addition, domestic para-aramid is also mostly used in the low-end market, and few can be used in military defense and aerospace. Therefore, the development and production of para-aramid and its products is still a technical problem in China.

Application fields of 2. aramid

1. Military Defense Field

Aramid composite materials can be used to manufacture solid rocket motor shells, pressure vessels, spacecraft cockpits, submarines, bulletproof armored vehicles, bulletproof armored vehicles, bulletproof armored vehicles, bulletproof panels, bulletproof helmets, bulletproof vests, etc.

2. Safety protection field

The flame retardant and high temperature resistance of personal protective equipment is an important condition to ensure the safety of personnel. With the development of material science and technology and textile processing technology, flame retardant protective clothing has gradually developed from temporary flame retardant finishing and semi-durable flame retardant finishing to durable flame retardant finishing and the application of essential flame retardant materials.

3. Rubber reinforcement field

Due to the large elasticity and low elastic modulus of rubber, it is easy to deform under the action of external force, so many rubber products must use fiber materials or metal materials as the skeleton. Cord fabric, cord, yarn, canvas, integral belt core, straight warp and straight weft fabric made of aramid are used as skeleton materials for tires, power transmission tapes, material conveying tapes and rubber hoses.

4. Environmental protection field

Aramid has excellent heat resistance, flame retardancy and chemical stability, and can work in high temperature and harsh environments for a long time. It is an ideal material for processing high temperature filter bags. It is used for high temperature dust filtration in areas with heavy air pollution such as steel, cement, and carbon black.

Non-woven fabrics woven from aramid 1313 fibers have very good dust filtering properties. For example, 380g/m² meta-aramid non-woven fabrics have better filtering properties than 530g/m² polyester fabric and 600g/m² acrylic fabric as high-temperature filter fabrics. In the field of bag dust removal, for the meta-aramid filter bag, the service life is more than two years under the condition that the exhaust gas temperature does not exceed 200 ℃, the humidity is 6%, and the SO₂ content is 100ppm.

5. Electrical and Electronic Materials

Antenna structure

Special printed circuit substrate

aramid insulation paper

optical fiber

6. Aerospace field

Aramid can be used to make secondary structural materials for large aircraft, such as cabin doors, windows, wings, fairing body surfaces, etc., and can also be used to make ceilings, warehouse walls, etc., which can reduce its weight.

7. Sports equipment field

Make full use of aramid high temperature resistance, fatigue resistance and other characteristics to produce harsh sports conditions of boxing gloves, hiking boots, racing car body, horse racing helmets, etc., can also be used to make rackets, skis, skis, bows, bowstrings, fishing rods, kite skeleton, golf clubs, rowing and so on.

Other areas

Sealing material

Rope

friction material

Building Materials

3. the development requirements of para-aramid industry in China

Para-aramid products are important key strategic materials in China. It is proposed in the "Made in China 2025" that by 2025, the technical maturity of domestic para-aramid and its composite materials will reach 9 levels. Establish a unified standard high-performance fiber material technology system, conquer the serialized high-performance fiber efficient preparation industrialization technology, carry out the composite material matrix material matching with domestic high-performance fiber, design technology, forming process, performance characterization, application verification and recycling and other research to ensure the demand for major equipment. The breaking strength of para-aramid reaches 20 ~ 22cn/dtex, and the elongation at break reaches 3%-4% ".

The "Textile Industry Development Plan (2016-2020)" issued by the Ministry of Industry and Information Technology (Ministry of Industry and Information Technology [2016] No. 305) and the "Chemical Fiber Industry" 13th Five-Year Plan "jointly issued by the Ministry of Industry and Information Technology and the National Development and Reform Commission" Development Guidance "(Ministry of Industry and Information Technology Lian Consumption [2016] No. 386), it is proposed to promote the research and development of high-performance fibers and their composite materials in the fields of construction and transportation, national defense and military industry, aerospace and other fields. Break through the key technical equipment, products and application industrialization technology of high-performance fibers such as para-aramid and composite materials, and promote the serialization of high-performance fibers such as para-aramid to meet the needs of downstream users.

Other documents of the state and ministries have also put forward requirements for the industrial development of para-aramid from different angles, such as "13th Five-Year" National Strategic Emerging Industry Development Plan (Guofa [2016] No. 67), "13th Five-Year" National Science and Technology Innovation Plan (Guofa [2016] No. 43), "New Material Industry Development Guide" (Ministry of Industry and Information Technology [2016] No. 454), strategic emerging industry key products and service guidance catalog (2016 edition "and other documents, it is proposed to improve the supporting system of raw and auxiliary materials, improve the yield and performance stability of materials, realize industrialization and large-scale application" and "break through the industrialization technology of high-strength and high-modulus carbon fiber and high-performance aramid engineering technology." carry out research and application testing of large-scale composite structural parts ", these policies play a supporting and encouraging role in the research and development and construction of para-aramid fiber in China.

4. the advantages of China's para-aramid industry

1. China's para-aramid technology is mature

At present, China's para-aramid production mostly uses low-temperature solution continuous polymerization, polymer separation, washing and drying with concentrated sulfuric acid to re-dissolve, dry spinning, washing and drying winding molding process. In the preparation of para-aramid spinning solution, the monomer is first dissolved in a solvent, and then polymerized in a uniquely designed reaction device to obtain a polymer with greater viscosity than the strong logarithm. The temperature control of this device is easy, the production is stable, and the production safety factor is greater, which ensures the smooth progress of spinning. In the solvent recovery stage, most enterprises extract NMP from water, and the waste water is sent to the distillation recovery unit for distillation separation as the raffinate phase. This process has high production safety, can save investment cost, and can achieve high recovery effect. Reasonable process route design, so that the product consumption continues to reduce, product quality is becoming more stable, the cost is gradually reduced, China's para-aramid production technology as a whole reached the international advanced level.

2. Para-aramid products with excellent performance

Para-aramid fiber has excellent mechanical properties and stable chemical properties. Its most prominent performance is high strength and high modulus, the strength is 3 times the strength of steel, is 4 times the polyester industrial yarn, the initial modulus can reach 414-1019 eN/dtex, 4 to 10 times the polyester industrial yarn, more than 10 times the polyamide fiber. It has a wide range of important uses in fiber optic cable reinforcement, bulletproof armor, asbestos substitution, composite materials, personal protection, etc. It is an important basic material in the fields of aerospace information technology, national defense and automobile industry, and is widely used in national defense and modern industry.

3. Increased demand from high-quality development of downstream industries

With the technological progress of domestic para-aramid, the further improvement of output quality and the gradual reduction of product prices will stimulate the product development and application expansion of the para-aramid downstream industry. At present, most of the para-aramid products consumed in China come from imports. With the high-quality production of domestic para-aramid products, some imported products will be replaced, and the potential market space is huge.

With more differentiated para-aramid products facing the market, it will fill the gaps in the existing domestic market, in fiber optic cable enhancement, bulletproof armor, asbestos substitution, composite materials, personal protection, aerospace, and information technology. It is an important basic material in the fields of national defense and automobile industry, and has broad market prospects. These factors will promote the rapid development of China's para-aramid industry in the near future.

Global production and market of para-aramid fiber in 5.

(I) international situation

1. International para-aramid production

Para-aramid was first developed successfully by DuPont in the 1960 s and began industrial production in 1972. Subsequently, the Netherlands, Japan, South Korea and Russia and other countries also began their own research work. Among them, the United States DuPont and the Japanese emperor in the field of para-aramid has a technical advantage.

In 2018, the production capacity of international para-aramid was about 92000 1t, and DuPont of the United States, Teijin of Japan, Kelon of Korea and Hyosung of Korea were the world's major producers of para-aramid. DuPont of the United States and Teijin of Japan account for about 65% of the world's total production capacity, with production capacity of 36000 Va and 26000 Va respectively, which are in a global monopoly position. Yantai Taihe has a para-aramid production capacity of 1 500t, ranking the international leader.

2. International para-aramid applications

In 2018, the global production of para-aramid was about 82000 t, and the downstream consumption was about 80000 t (Table 1). The production of DuPont and Teijin accounted for about 70% of the global consumption of para-aramid.

Among the main application fields, aerospace and sports equipment use fiber accounted for 35%, automobile tire radial and conveyor belt materials use fiber accounted for 20%, high-strength rope fiber accounted for 10%, body armor and helmet fiber accounted for 11%, other construction, rail transportation and other reinforcement materials accounted for 25%. It is estimated that in the next 5 years, the global demand for para-aramid will reach about 130000 t, and the market has huge room for growth.

(II) domestic situation

1. Domestic market demand

In 2018, the domestic consumption of para-aramid was about 10000 t, of which the consumption of fiber optic cable reinforcement was 4000~5000t and the consumption of safety protection fabric was about 3000t. With the rapid development of China's transportation, optical fiber communication, high-speed railway, aviation reinforcement, light-weight car radial tire cord fabric and brake pads and other fields and protection applications, the demand for aramid will show a more vigorous situation. At present, the domestic production capacity of para-aramid plant exceeds 10000 t, but the actual effective production capacity is about 2000t, the output is about 1500t (Table 2), and only about 2% is used for export. In China's market demand for para-aramid, in addition to the domestic supply of 1,500t products, the rest all come from imports. The supply of DuPont and Teijin is 5000~6000t. The output of domestic para-aramid is far less than the market demand, so there is huge room for development.

In the next 5 to 10 years, with the improvement of the performance of para-aramid in my country, the continued enrichment of product specifications, and the high-quality development of downstream manufacturing and application fields, the expansion of para-aramid production scale will reduce manufacturing costs. The consumption of para-aramid will be more applied to the military, aerospace, aviation, sports and leisure equipment and construction fields, and the market demand growth rate is expected to remain at about 10%. By 2025, the demand for para-aramid will reach 20,000 t.

2. Para-aramid market situation

Para-aramid is a typical dual-use material for military and civilian use. In military use, para-aramid fiber fabric has the performance characteristics of high tensile strength, high elastic modulus and low density. It can quickly absorb and disperse the impact energy of bullets. Avoid causing "blunt injury", so the protective effect is significant, and it is known as the "ultimate bulletproof material". It is widely used in individual protective equipment such as bulletproof vests, bulletproof helmets, bulletproof helmets, search and explosive suits, and police training uniforms.

As of the end of 2018, the global total of para-aramid production capacity of about 76000 t/a, mainly concentrated in DuPont, Teijin Company; China's existing para-aramid scale production enterprises 3, effective production capacity of about 2000t/a. Downstream mainly focuses on safety protection, automotive friction materials, fiber reinforced protection, rubber reinforcement, etc.

Military market for para-aramid

The United States has developed the famous PASG ton helmet using Kevlar materials, which is the world's first bulletproof helmet with a large number of equipment. After that, countries began to develop bulletproof helmets, and the materials were basically para-aramid. At present, our army is generally equipped with QGF02/03 Kevlar bulletproof helmets, while some troops are still equipped with old GK80 helmets, and there is still a need for replacement. According to the bidding results of the new military helmet in the bidding center of the army equipment department at the end of 2018, the bidding quantity is not less than 350000, and the helmet body is made of aramid material. based on 2kg/top, it is estimated that the demand for para-aramid fiber is about 700 tons.

In addition, the composite material made of para-aramid has excellent lightweight effect and bulletproof performance, and its application in weapons and equipment and other fields will gradually improve. For a long time in the past, Western countries have been embargoed on China as a strategic material control, and China's production is very small, raw materials are subject to people make it difficult for China to apply in the field of national defense and military industry on a large scale, with the acceleration of the process of localization, the application of national defense and military industry is expected to grow rapidly.

Para-aramid civilian market

In the civil market, para-aramid is used in information communication (optical fiber protection enhancement); para-aramid is used in the automotive industry, including brake pads, tire reinforcement, and automotive hoses.

Para-aramid has the characteristics of high strength and high modulus, low density and creep resistance, so it is often used as a reinforcing material for supporting optical fibers and cables to protect optical fibers and cable cores from axial strain caused by overload. The non-flammability of the fiber also plays a certain role in fire protection in the use of the cable. Therefore, para-aramid fiber is widely used in indoor and outdoor optical fiber and power cable reinforcement, which plays an important role in promoting the development of a new generation of communication technology in China.

In July 2012, my country upgraded the broadband upgrade project to a national strategy, that is, the "Broadband China" strategy. In the following years, the length of new optical cables and the output of optical cables in my country increased rapidly, driving the demand for para-aramid. In recent years, with the popularity of broadband households and the retreat of the tide of 4G construction, China's optical cable production and new length has slowed down. At present, the consumption of para-aramid fiber protection enhancement in China is about 4-5 thousand tons, and the supply of domestic enterprises is nearly 6-7 hundred tons, and the stock substitution space is more than 3000 tons. And 2019 as the first year of 5G, the future 5G construction capital expenditure will gradually increase, is expected to re-drive the growth of fiber optic cable demand, fiber enhanced protection with the use of aramid consumption will be further increased.

Para-aramid is also suitable for reinforcement of tire radial and other rubber products. Aramid reinforced tires have higher driving speed, handling and comfort, and can also reduce body weight, reduce rolling friction and driving noise, reduce "out-of-plane bending stiffness", reduce rolling friction, reduce fuel consumption, and have energy saving, Low noise and long life characteristics. At present, Goodyear, Michelin, Pirelli, Bridgestone and other international tire manufacturers have commercialized the application of para-aramid reinforced tires supporting various high-end models. Domestic Wanli tires, Qingdao Sen Kirin and Double Star tires have carried out the research and development of para-aramid reinforced passenger tires, while Lingling tires, triangle tires and double money tires have carried out the research and development and production of para-aramid reinforced radial tires. In addition, the knitting (or weaving) process is used to process the para-aramid twisted wire into a grid cloth, and then compounded with rubber. It is now widely used in automotive hoses, such as cooling water pipes, fuel pipes, brake pipes, and especially turbocharged pipes. Domestic automotive hose representative enterprises have Meichen Ecology, Anhui Zhongding, Tianjin Pengling, Zhejiang Jun and so on, aramid hose has been for Volkswagen, GM, Chery and other main car factory support.

Suggestions on 6. the development of para-aramid fiber industry in China

1. Establishment of para-aramid standard and evaluation system

Establish a standard system and evaluation system suitable for the actual situation of para-aramid in China, formulate appropriate standards for technical indicators, meet the needs of the leading market, and are suitable for production, use, research and downstream users. Intensify the formulation of group standards, fill the gaps in the national standard industry standards of para-aramid, and timely formulate certain advanced strategic key technical guidelines to lead the sound development of China's para-aramid industry.

2. Establishment of industrial chain cooperative development mechanism

Innovate the R & D system of para-aramid basic research, key engineering technology research and applied research, establish relevant majors and research projects in suitable characteristic schools, cultivate multidisciplinary and lightweight talents, and support the training of a group of academic leaders and engineering technology leaders.

Coordinate the upstream and downstream enterprises in the industrial chain, develop downstream conforming material products adapted to the performance of para-aramid, and use demonstration projects to establish key technologies and production capacity in the industrial chain, so that enterprises in the industrial chain can form economies of scale, improve varieties, reduce costs, and improve competitiveness.

3. Development of differentiated para-aramid products

The current international development of para-aramid is characterized by advanced technology to promote the upgrading of application products, such as DuPont developed a series of new para-aramid varieties, such as ultra-high strength type, ultra-high modulus type, medium modulus type, high bonding type, anti-fatigue type, etc. The market for para-aramid fibers is also influenced by high-performance fibers such as carbon fibers, ultra-high molecular weight polyethylene fibers, and polyimide fibers. These fibers have also made breakthrough progress in the past five years, the level of process technology continues to improve, fiber performance gradually improved, product structure is more abundant, some product costs have decreased, downstream applications continue to expand, these high-performance fibers will be in specific areas of the formation of the impact of aramid products.

4. Cultivate leading enterprises and participate in international competition

Give full play to the advantages of China's chemical fiber industry's high basic level and large market capacity, focus on cultivating 10,000-ton para-aramid and its application scale enterprises, and strive to establish large-scale para-aramid and composite new strategic industries in the world. Increase the scale of enterprises in the industrial chain, promote it to other manufacturing industries, focus on increasing the scale of enterprises in the industrial chain, form economies of scale, reduce costs, improve competitiveness, and participate in international competition.