Carbon fiber composite is the first choice of composite materials in aviation industry at present, which has largely replaced metal. For example, shell parts such as aircraft rockets belong to the forefront of materials science.
A brief introduction is as follows
197 1 year, Toray became the first manufacturer in the world, engaged in the industrial production of pan-based carbon fiber, and named its product "TORAYCA", which is the abbreviation of Toray carbon fiber. At present, Toray is a global leader in carbon fiber production and marketing.
At present, two kinds of carbon fibers are mainly produced in the world. One is pan-based carbon fiber with polyacrylonitrile as raw material, and the other is pitch-based carbon fiber, which is distilled from synthetic pitch in coal and petroleum and then polymerized into synthetic fiber. Polyacrylonitrile-based carbon fiber is superior to butadiene pitch-based carbon fiber in strength, so it has an absolute overwhelming advantage in carbon fiber production all over the world.
1. Production technology of carbon fiber
For the production process of carbon fiber, when producing polyacrylonitrile-based carbon fiber, polyacrylonitrile fiber called "matrix" must first undergo polymerization and spinning treatment. Then, these precursors are put into an oxidation furnace and oxidized at 200 to 300 degrees Celsius. In addition, the carbon fiber will be carbonized in a carbonator at a temperature of 1000 to 2000 degrees Celsius. Polyacrylonitrile-based carbon fiber includes coarse fiber besides conventional fine carbon fiber, which is called "human tow carbon fiber", and the production cost of this coarse fiber is relatively low.
2. Carbon fiber characteristics
As people usually say, carbon fiber is lighter than aluminum and harder than steel. Their specific gravity is a quarter of that of iron and their specific strength is ten times that of iron. Through this comparison with other fibers, you can get a preliminary understanding of the characteristics of carbon fiber. Also, carbon fiber is first of all a substance, which is made of the same material as carbon and diamond. For this reason, in addition to superior tensile strength and tensile modulus, the chemical composition of carbon fiber is very stable and has high corrosion resistance. Other characteristics of carbon fiber include high X-ray penetration, high chemical resistance, heat resistance and low temperature resistance. These characteristics of carbon fibers mean that they can be used in many fields. The main applications include sports, such as golf clubs and fishing rods; Aviation applications include aircraft components; And industrial application. With the continuous progress of industry, people are looking for many materials with new energy. The demand for carbon fiber is increasing gradually, and it is widely used in medical devices and pressure.
Containers, civil engineering and building materials, energy and other new industrial applications. The production cost of carbon fiber is gradually decreasing, and the processing technology tends to be diversified. Manufacturers can provide a range of carbon fiber products according to specific applications. All these support a new type of response centered on industrial applications.
3. Product form and manufacturing process of carbon fiber
Carbon fiber has four product forms: fiber, cloth, prepreg and chopped fiber. Cloth refers to the fabric made of carbon fiber. Prepreg is a product in which carbon fibers are arranged in one direction and impregnated with carbon fibers or cloth resin to make them into sheets. Short fiber refers to short silk. According to different proportions, these products and resins will be used together to form carbon fiber reinforced plastics (CFRP). The resin attached to the fiber can be made into pressure vessels and rollers, wound around the core, and then plasticized or hardened. This method is called "winding forming method". Put the cloth into the model, then soak it in resin, and you can make the body part of Chuanfan brand = rowing boat. This is called "resin transfer molding (RTM)". Aircraft components are manufactured by heating, pressurizing and plasticizing prepregs in an autoclave. The prepreg is wound around the core, then heated and plasticized. This is the so-called "sheet winding method", which can be used to make golf clubs and fishing rods. Short silk can be mixed with resin to form a mixture, which can be processed to produce parts of mountain machinery and other products.
In the past, prepreg was the most widely used form of carbon fiber, which was prefabricated by winding sheets in a reaction kettle. Recently, however, with the development of new industrial applications, fiber winding, mixing and other prefabrication methods have been more widely developed. The application of RTM and other molding methods enables manufacturers to manufacture large products more effectively. The combination of carbon fiber with the most suitable resin and prefabrication process makes the application of carbon fiber more attractive.
4. Application development
At present, the proportion of various applications in the annual demand of carbon fiber is as follows: sports application is about 30%, aviation application 10%, and industrial application is 60%. Three important sports applications are golf clubs, fishing rods and tennis racket frames. At present, it is estimated that the annual output of golf clubs is 34 million. According to the classification of national interests, these golf clubs are mainly produced in the United States, China, Japan and China. The United States and Japan are the main consumers of golf clubs, accounting for more than 80%. Carbon fiber Goyle 40% of the big stumps in the world are Toray's carbon fiber. The output of carbon fiber fishing rods in the world is about 20 million pairs per year, which means that there is a steady demand for carbon fiber for this application. The market capacity of tennis racket frames is about 6 million pairs per year. Other sports applications include ice hockey sticks, ski poles, archery and cycling. At the same time, carbon fiber is also used for boating, boating, surfing and other marine sports. 1 992 The demand for carbon fiber in Yingchuan began to decrease, mainly due to the decline of commercial aircraft industry, but it quickly recovered in the early stage of 1995. The main reason for the recovery is that the overall production efficiency has improved, and the Boeing 777 aircraft has been fully produced. Toray's carbon fiber is used as structural material, including horizontal and vertical transverse tail fins and beams. These two parts are very important. If damaged, the whole plane may crash during the flight. These materials are called "main structural materials", because they are very important, so their quality requirements are extremely demanding. Toray is the only qualified carbon fiber manufacturer designated by Boeing Company for Boeing 777. European Airbus also uses a lot of carbon fiber on their planes, and TORAYCA carbon fiber from Toray is expected to be widely used on their new passenger plane A380. In the industrial field, carbon fiber is also widely used. As a material, they are replacing metal and concrete to meet the requirements of environment, safety and energy, and the demand for carbon fiber in industrial field is on the rise. In the field of civil engineering and architecture, the application of carbon fiber seismic repair and reinforcement method is a major breakthrough and is being more widely promoted in this field. In railway construction, large roof systems and sound insulation walls will have good applications in the future, and these will also be very promising applications. Pressure vessels are mainly used on compressed natural gas (CNG) tanks of automobiles, as shown in the figure, and also on fixed breathing apparatus (SCBA) of firefighters. CNG tanks originated in the United States and European countries, and now Japan and other Asian countries have shown great interest in this application. Other applications of carbon fiber include the production of composite materials for machine parts, household appliances, microcomputers and semiconductor-related equipment, which can be used to strengthen swords, prevent static electricity and protect electromagnetic waves. In addition, in the X-ray instrument market, the application of carbon fiber can reduce human exposure to X-rays. With the continuous reduction of the cost of carbon fiber worldwide and the improvement of environmental protection requirements, carbon fiber has been applied to the automotive field. In the future, they will be used as materials for tail boilers, engines, transmission shafts and oil tanks, with good development prospects.
5. History of carbon fiber market
The full commercialization of carbon fiber began in 1970s, which was the introduction and development period of golf clubs and fishing rods, mainly in Japan. In the early 1980s, carbon fibers began to be widely used as structural materials for passenger planes and airplanes, mainly in Europe and North America. Subsequently, people's understanding of carbon fiber increased, and they began to regard it as a material for high-quality seedlings, and it developed rapidly in the mid-1980s. In the mid-1980s, Airbus began to use CFRP as the main structural material of aircraft. And with the application of carbon fiber in tennis and new sports, the carbon fiber market is expanding steadily. Although 199 1 after the Gulf War, the development of aviation industry fell into recession, the global economy began to stagnate, and the demand growth of carbon fiber also tended to slow down. In the mid-1990s, the carbon fiber industry should just start to become a new demand growth point. Especially in Europe and North America, carbon fiber has been applied to pressure vessels, and this growth is very significant. Due to the Kobe earthquake of 1995, the demand for seismic strengthening application has been accelerated. In the future, it is expected that the main application fields of carbon fiber will focus on industrial applications, and this demand will grow steadily. In addition, the new space program and steam-related applications will promote the industrial application of carbon fiber.
6. Supply and demand situation
In 2004, the production capacity of conventional carbon fiber was about 25,000 tons, of which 75% was produced by relevant Japanese manufacturers. In addition, the output of low-cost crude carbon fiber, which is called "artificial tow type", is also several thousand tons. Man-made tows have been used in low-end sports and industrial applications, and also in areas that used to involve only glass fibers.
For carbon fiber rice, it is usually said that 70% of the declared capacity is the actual capacity. The declared capacity is usually calculated on the basis of standard product types, but for carbon fiber, there are many other grades of products according to technical characteristics besides standard products with standard strength and modulus. Fiber thickness is also different, so their production capacity is different according to product type and fiber thickness. When producing a variety of products, changing production will be a waste of time. Therefore, the actual capacity is usually lower than the published capacity. Global demand and demand forecast from 2003 to 20 10. During the period of 20 10, the demand for carbon fiber will increase by 7.5% every year. It is estimated that by 20 10, the total demand for carbon fiber will reach 32,000 tons.