Polyetheretherketone (PEEK) is a semi-crystalline, thermoplastic special engineering plastic developed by the British Imperial Chemical Industry Company (ICI) in 1978. Because PEEK has excellent comprehensive properties such as high temperature resistance, self-lubricity, corrosion resistance, flame retardancy, hydrolysis resistance, wear resistance and fatigue resistance, it was initially used in the field of defense and military industry, and gradually expanded to civilian use. Fields include industrial manufacturing, aerospace, automotive industry, electrical and electronic, and medical equipment. With the continuous improvement of PEEK synthesis and processing technology, its high-performance materials obtained through chemical modification, blending, compound filling, etc. have broadened its application fields. PEEK is suitable for various processing methods such as injection molding, extrusion molding, compression molding and melt spinning. In recent years, the combination of PEEK resin and advanced manufacturing technologies such as 3D printing has made it a new development direction in the medical field such as medical implants.
Development path
Initial gestation stage (1978-1992):
British ICI developed PEEK and its glass fiber and carbon fiber reinforced products, applied for patents and industrialized it, with a production capacity of 1,000 tons / year, mainly used in the field of defense and military industry.
Monopoly development and disintegration stage (1993-2004):
The British company Victrex (Victrex) acquired the PEEK business from ICI, showing a monopoly development trend and continuously expanding its production scale. In 2003, the production capacity was increased to 2800 tons / year, and the application field was also expanded from the initial military to industrial and biomedical. Civilian field.
Because PEEK is mostly used in the military field, Victrex blocked it. With the strong support of China's policies, Professor Wu Zhongwen's team at Jilin University independently developed the PEEK patented technology with independent intellectual property rights, and founded Jida High-tech Materials Co., Ltd. and put it into production. Chittagong Hi-Tech became the first company to break the monopoly of Victrex.
Comprehensive development stage (2005-present):
In 2005, Evonik acquired Chittagong High-tech and Solvay acquired the PEEK business of Garda in India; in 2009, China Jinfa Technology Co., Ltd. and Panjin Zhongrun Special Plastic Co., Ltd. entered the field. PEEK Enter the stage of comprehensive development. In addition, PEEK's modified compounding and processing technology is gradually developed, and its application field is also expanding.
Production and processing technology
(1) Mainstream synthesis methods
The existing PEEK synthetic production process routes are mainly two types of nucleophilic substitution chemical reactions and electrophilic substitution chemical reactions. Among them, the electrophilic process is prepared by low-temperature reaction using diphenyl ether and m-phthaloyl chloride as raw materials. Its advantages are mild conditions and convenient source of raw materials, but there are more side reactions such as polymer branching and crosslinking. At present, the international industrialization is mainly the first type of nucleophilic process.
The basic idea of the nucleophilic process is to use 4,4-difluorobenzophenone and hydroquinone as raw materials, in the presence of anhydrous sodium carbonate, and with diphenyl sulfone as the solvent, through nitrogen protection, gradually increase When the temperature is close to the melting point of the polymer (320 ° C), the condensation reaction yields high molecular weight PEEK. The advantage of this process is that the side reactions such as branching and cross-linking of the polymer are easier to control. No metal-based catalysts, stabilizers or additives are used in the process, and high-purity PEEK powder can be produced. However, this reaction path has the disadvantages of harsh reaction conditions, complicated synthesis process, expensive monomer and high cost.
Over the years, all mainstream production companies have carried out further research and development and improvement on the basic ideas of the pro-nuclear process, overcame the drawbacks, and reduced costs, forming their own core process routes, which is also the core value technology of the PEEK synthesis industry.
(2) Processing and modification technology
As a representative of thermoplastic engineering plastics, PEEK has the characteristics of easy processing. It is suitable for conventional plastic processing molding methods including injection molding, extrusion molding, compression molding and melt spinning. In recent years, with the continuous development of 3D printing technology, PEEK, as a representative of 3D-printable polymer materials, has expanded its application in the field of medical devices, especially medical implants with complex morphological structures.
At the same time as the development of processing technology, with the improvement of market performance requirements for materials, the modification and compounding of PEEK has become a hot spot in the industry in recent years. In addition to chemical modification by changing the composition and / or ratio of the polymer main chain during the polymerization stage, common performance improvement methods in the industry include surface modification, blend modification and composite filling enhancement, etc. Improve PEEK's molding performance and performance.
Main application areas
PEEK has excellent comprehensive properties and can replace traditional materials such as metals and ceramics in many special fields. PEEK has applications in machinery manufacturing, aerospace, automotive industry, medical, electrical and electronic, pharmaceutical and food processing industries, among which the transportation industry (including automotive and aviation), machinery industry, and electrical and electronic industries account for the highest proportion.
Future trends
After more than 40 years of application development, PEEK's product types and models, participating enterprises and application fields are constantly expanding, maintaining a high industry growth rate. However, due to its higher price, it has less market share in special engineering plastics. Over the years, mainstream European and American companies have combined expansion through mergers and acquisitions and independent development (or cooperative development), relying on expanding production scale to produce scale effects, actively developing modified and compound new products, and through cooperative development of downstream industries to continuously expand the scope of application To find a way out.
Although our country has independent research and development technology of PEEK synthesis, and to a certain extent, it solves the problem of excessive cost of PEEK raw materials. However, the development of China's PEEK industry chain is still far behind that of developed countries, especially in the expansion of high-value-added downstream applications, it is difficult to occupy an advantage due to the restrictions of the overall industrial manufacturing capacity. With the development of China's large aircraft, rail cars, automotive industry, medical and defense military industries, the demand for special engineering plastics represented by PEEK is also increasing, especially in terms of improving the production and processing capabilities of high-performance products.