Wet spinning process for preparing carbon fiber with important strategic significance
High-performance polyacrylonitrile (PAN)-based carbon fiber is a military-civilian new material that is related to national strategic security. It has been subject to a strict embargo by the international community for a long time. The research and development of key equipment areas have been severely restricted. As an important technology for carbon fiber for defense equipment The basic wet spinning process is also a key technology shortcoming in the research of domestic carbon fiber.
Due to the influence of the preparation technology of carbon fiber raw silk, until the end of the last century, the development of carbon fiber technology in China has been hovering at a low level that cannot be industrialized. Carbon fiber for structural composite materials of national defense equipment is completely dependent on imports, bringing national security and development There are great hidden dangers, and there is an urgent need to develop carbon fiber localization technology that meets the needs of high-end equipment in key areas of China to achieve independent protection of key materials.
PAN-based carbon fiber preparation has the longest process flow in the field of materials, including polymerization, spinning, pre-oxidation, carbonization (graphitization), surface treatment and other process links. Among them, the carbon fiber prepared by the PAN solution wet spinning process has a unique surface groove structure, which is beneficial to improve the interface performance of the carbon fiber resin matrix composite material used as the structural material. China's defense field represented by aerospace has long used carbon fibers prepared by wet spinning processes. Therefore, the development of the wet spinning process for the preparation of carbon fibers has important strategic significance and market value in China.
"Created a carbon fiber variety", formed a series of products based on wet spinning process
WHTZ Carbon Fiber Technology Group takes the preparation of carbon fiber composite materials as the technical and industrial basis, and actively leads China's PAN-based carbon fiber localization technology research and industrialization construction.
Fiber defect control, fiber surface section morphology control, multi-spinning/multi-tow process state consistency control of traditional dimethyl sulfoxide wet spinning technology, and carbon fiber performance/specification serialization to meet the needs of high-end applications For technical research and other problems, WHTZ cooperates with Beijing University of Chemical Technology, Fudan University and other scientific research units to build on the independent innovation and original innovation of process technology. The new technology and industrialization technology for preparing carbon fiber raw silk through the dimethyl sulfoxide wet spinning process Innovation, combined with the re-innovation of key equipment, has achieved a number of key technological breakthroughs-
Break through the key technology for the efficient preparation of high-quality spinning solution, and solve the problem of de-singling and de-foaming of high-solids and high-viscosity polymer solutions;
Developed integrated washing/drawing combined drafting process and equipment, independent innovation of new multi-spin spinning technology, effectively improving the quality consistency and stability of multi-spun raw yarn;
Developed high-efficiency raw yarn drafting process and equipment with temperature gradient characteristics to achieve effective control of carbon fiber modulus to meet aviation needs;
Successfully developed the new technology of the hot air interactive conveying pre-oxidation furnace, breaking the traditional four-temperature zone model, establishing a new process of the six-temperature zone, and breaking the bottleneck of the 3-meter-wide pre-oxidation production equipment with high efficiency and long-term stable operation;
Developed a new low-denier PAN yarn spinning technology to realize the radial homogenization of low-denier yarns and the structural optimization of high axial orientation;
Developed fiber pre-oxidation technology with controllable structure combination, which solved the technical problems of carbon fiber medium and high modulus preparation;
Developed domestic key equipment technology integrating simulation design, manufacturing and operation tube, and solved the problem of quality consistency of carbon fiber industrialization with different modulus.
Through systematic technical research, developed serialized technologies and products based on tensile strength, serialized technologies and products based on tensile modulus, and serialized technologies and products based on tow specifications, realizing large-scale production of high-performance carbon fibers And large-scale applications, the establishment of a complete technology development and 1000-ton industrialization system based on wet spinning technology to prepare high-strength carbon fiber.
The mechanical properties of the T300 and T800 carbon fiber products developed and produced by this project exceed the level of similar products of Japan Toray Company, and their performance stability is equivalent to it. The 300m/min spinning speed in the multi-spinning state of the breakthrough makes the industrial wet The spinning rate is increased by more than 1.5 times. The original innovative new high-strength carbon fiber products have tensile strength and modulus up to the level of Toray T700S carbon fiber in Japan, and the interfacial performance of the composite material is superior to this product (Toray only has the dry and wet T700 grade, and there is no wet T700 grade), expert The appraisal believes: "A carbon fiber variety with high strength of T700 grade carbon fiber and excellent surface structure performance of T300 grade carbon fiber was created."
Practice the development strategy of domestic carbon fiber with strong strength
WHTZ's stabilized carbon fiber products based on the wet spinning process have been widely used in the defense construction of aviation, aerospace, weapons, electronics, etc., high-end industrial equipment such as wind power and civil engineering. It is the main supplier of carbon fiber for China's defense field and the aviation field. The first and largest supplier has broken the monopoly of foreign countries in this field, achieved independent protection of domestic key strategic materials, and has also become the largest carbon beam supplier in China of Vestas, an international leading wind power company.
For "Industrial preparation technology of high-strength PAN-based carbon fiber based on wet spinning process", independent innovation based on DMSO batch polymerization and wet-spinning is realized, and large-scale and stable preparation of high-strength/high-strength medium-mold PAN-based carbon fiber is achieved on a large scale, covering GQ3522 ( T300 level), GQ4522 (T700 level) and QZ5526 (T800 level) series products support the application of composite materials for key batch models of national defense. The overall achievements reached the international advanced level." The project won the first prize of the 2019 China Textile Industry Federation Science and Technology Progress Award.
WHTZ, which has always attached importance to intellectual property strategy, has obtained 11 national invention patents and 18 utility model patents in the field of PAN wet spinning to prepare high-performance carbon fibers, and led the preparation of China's first "polyacrylonitrile-based carbon fiber" Standards, formulated a series of enterprise product standards.