Carbon fiber can be divided into small tow and large tow according to the number of fibers, and can be divided into four categories according to mechanical properties: high-strength type, high-strength medium model, high model, and high-strength and high-strength model. Small tow carbon fiber is mainly 1K, 3K, and 6K in the early stage, and gradually develops into 12K and 24K, which are mainly used in high-tech fields such as national defense and military industry and sports and leisure products, such as aircraft, missiles, rockets, satellites and fishing gear, golf clubs, tennis rackets, etc. Large tow carbon fiber usually refers to carbon fiber above 48K, including 48K, 60K, 80K, etc., which are mainly used in industrial fields, including textiles, medicine and health, electromechanical, civil engineering and construction, transportation and energy. The development of the carbon fiber industry has formed two paths: high performance and low cost.
(1) In the aerospace field, the performance improvement of carbon fiber composites has promoted their large-scale application. High-performance carbon fiber aims to continuously improve the strength and elasticity of carbon fiber, and expand the proportion of carbon fiber composite materials in aerospace applications, such as the application of carbon fiber composites in aircraft, in the early 80s of the 20th century, only used as non-load-bearing components, the dosage accounted for only 5%-6%, with the improvement of the performance of carbon fiber composites, gradually used as secondary load-bearing components and main load-bearing components, the dosage accounted for 50%.
(2) In the industrial field, the cost reduction of carbon fiber has promoted its large-scale application. In the mid-to-late 90s of the 20th century, a major breakthrough was made in the technology of large tow carbon fiber, with the strength reaching T300 level, and at the same time, a breakthrough was also made in the preparation of large tow carbon fiber prepreg. Based on large tow carbon fiber, civilian acrylic precursor yarn is used, and has higher production efficiency, and its cost is only about 20% of small tow carbon fiber.
