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Carbon Fiber: "The Pearl On The Crown Of Materials"

2024/9/3 11:14:00 2

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　　 Airplanes, wind turbine blades, cable-stayed bridges, professional bicycles, badminton rackets... these seemingly unrelated things actually use the same new material - carbon fiber.

　　 This high-quality material has complicated technical processes behind it. There are no tricks and shortcuts to conquer core technologies. In the face of foreign technology blockade, the Chinese people have experienced a difficult R&D process in order to remove carbon fiber, which is the "pearl on the crown of materials".

　　 "Pearl on the crown of materials"

　　 "Carbon fiber is a kind of magical material." In the opinion of Luo Haoyu, secretary of the Party Committee and deputy general manager of China Building Materials Group, materials are the foundation of manufacturing industry, while carbon fiber related products are widely used in aerospace, wind turbine blades, sports and leisure, pressure vessels, carbon/carbon composites, transportation construction and other fields, and its importance is self-evident.

　　 The reason why it is so widely used is related to the characteristics of carbon fiber.

High temperature resistance test of carbon fiber. Photographed by Li Taiyuan

　　 Carbon fiber has excellent mechanical properties and chemical stability. Its density is lower than that of aluminum, strength is higher than that of steel, and corrosion resistance is higher than that of stainless steel. It is the fiber with the highest specific strength and modulus among the high-performance fibers that have been mass produced at present.

　　 A 1-meter long bundle of SYT65 (T1000 grade) carbon fiber weighs only 0.5g, but its strength can bear about 500kg. A bunch of carbon fiber with thick fingers can pull two planes.

Corrosion test of carbon fiber in aqua regia. Carbon fiber (left) has no reaction in aqua regia, and iron wire (right) has corrosion reaction. Photographed by Li Taiyuan

　　 In addition, the ultra light bicycle frame made of carbon fiber can be lifted with only two fingers; Even if the carbon fiber is put into the highly corrosive "aqua regia", it is still "calm", and it is difficult to observe the obvious reaction with the naked eye.

The ultra light carbon fiber bicycle frame can be lifted by two fingers of girls. Photographed by Li Taiyuan

　　 Corresponding to such high-quality characteristics is the complex production process of carbon fiber.

　　 Public data shows that the production of carbon fiber can only be completed through hundreds of processes, more than 300 key technologies, more than 3000 process parameters, and more than 10 systems integration. Therefore, carbon fiber is also known as the "pearl on the crown of materials".

　　 "Burn down a Santana one day"

　　 In order to take off this "pearl on the crown of materials", researchers have gone through a difficult research and development process.

　　 The research and development of carbon fiber in China began in the early 1960s, but the key core technologies failed to make breakthroughs for many years, leading to the serious dependence on imports of related products.

　　 On the other hand, the "carbon fiber power" that has mastered the core technology will implement the "technology, equipment and products" three blockades on the carbon fiber that China needs. Chinese R&D personnel have to "find another way".

　　 In September 2005, Zhongfu Shenying officially launched the carbon fiber project. Since then, it has successively conquered the key technologies of the whole process, such as high temperature drafting machine, wet spinning process hundred ton line, thousand ton line precursor preparation and carbonization process. In 2007, the first batch of carbon fiber produced by Zhongfu Shenying was put off the production line; In 2008, it built a thousand ton SYT35 (T300) carbon fiber production line.

　　 From 2006 to 2012, Zhongfu Shenying was mainly engaged in the R&D and production of wet process T300 carbon fiber, built a thousand ton SYT35 (T300 grade) carbon fiber production line, and achieved stable production.

　　 However, the "upgrade" from T300 carbon fiber to SYT65 (T1000) carbon fiber is not as easy as expected. Even in the climax of R&D, the enterprise "burns down a Santana every day".

　　 Lian Feng, general manager of China Building Materials Zhongfu Shenying Xining Company, told reporters that during this period, the company's annual investment reached "hundreds of thousands". "Because we have invested a lot of R&D expenses in the early stage, and there are no new products, this is the 'darkest period' of our development, and we are losing money every day."

　　 After numerous failures, Zhongfu Shenying 1000 ton carbon fiber production line was officially put into production in 2008. In 2012, the first dry jet wet spinning thousand ton T700 production line of Zhongfu Shenying was completed and put into operation, becoming the largest and most advanced high-end carbon fiber production line in China at that time. In 2018, the project of "dry jet wet spinning thousand ton high strength/hundred ton medium model carbon fiber industrialization key technology and application" led by Zhongfu Shenying won the first prize of the National Science and Technology Progress Award.

　　 The Chinese have successfully made "Chinese carbon fiber" with the world's advanced dry jet wet spinning technology.

Carbon fiber production line. Photographed by Li Taiyuan

　　 "One innovation" drives "N innovation"

　　 "It's very easy to say now, but it was really too difficult at that time," said Zhang Guoliang, chairman of Zhongfu Shenying.

　　 "For example, the most difficult part of this link is how to quickly pull the spinning solution trickle through the water in such a short time. After the spinning solution enters the water, it has no strength, but it needs to be pulled forward at a very fast speed, and it needs to form strength immediately. What should we do? It depends on the temperature. Just trying this temperature, we tried countless times at that time, and finally succeeded. Another example is the spinning speed. Under the dry jet wet spinning process, it means that we need to increase the spinning speed from 70 m/min to 80 m/min to 400 m/min. This technical difficulty is even more conceivable. It can be said that the theoretical model of this process is summarized step by step and built little by little. " He said.

　　 The 10000 ton carbon fiber base has been put into production since the initial attempt in technology. Raw material enterprises conquer the core technology, and various downstream production enterprises can use new materials to make new products, realizing "one innovation" and "N innovation".

　　 In September 2021, Zhongfu Shenying Xining ten thousand ton carbon fiber base located in Xining, Qinghai, will be put into production, which is also the world's highest altitude high-performance carbon fiber production base; After full production, the base has become the only high-performance carbon fiber production base with a scale of more than 20000 tons in the world.

Finished carbon fiber. Photographed by Li Taiyuan

　　 Lian Feng said frankly, "This is not only our response to market demand, but also the strategic deployment of the Group in the field of new materials, which is to make the new materials industry chain bigger and stronger."

　　 He said that at present, the base mainly produces T700, T800 and T1000 products. "After a large number of these products are supplied to the market, they can further meet the application in many fields such as domestic aerospace, wind, light, hydrogen, new energy, etc., while also ensuring the independent production capacity of our country's carbon fiber, and realizing the localization of materials in key fields."

　　 It is understood that at present, the headquarters of Zhongfu Shenying Lianyungang has successfully prepared T1100 carbon fiber.