Special engineering plastics, also known as high-performance polymers, are generally developed according to the needs of special applications. Compared with general-purpose engineering plastics, their performance is more excellent and unique. The long-term use temperature is above 200 ° C.
Since the introduction of polyimide (PI) in the 1960s, the main varieties that have been successfully developed and industrialized are polyimide (PI), polyimide (PAI), polyetherimine (PEI), and polyphenylene sulfide. (PPS), polysulfone (PSF), polyethersulfone (PES), polyetheretherketone (PEEK), liquid crystal polymer (LCP), and fluoroplastics.
Polyetherimine (PEI) is a typical thermoplastic polyimide with excellent comprehensive properties. It is mainly used in electronics, electrical machinery and aviation industries, and is used as a metal substitute in the field of traditional products and cultural and daily life products.
In the electrical and electronics industry, parts made of polyetherimide are widely used, including high-strength and dimensionally stable connectors, circuit boards, coils, flexible circuits, reflectors, and high-precision optical fiber components. Using it instead of metal to make optical fiber connectors can optimize the component structure, simplify its manufacturing and assembly steps, and maintain more accurate dimensions.
In the field of aviation and automobile transportation, PEI can be used to manufacture various parts of aircraft, such as portholes, nose parts, seat backs, inner wall panels, door coverings and various objects for passenger use. In the automotive sector, PEI is used to make high-temperature connections, high-power lights and indicators, temperature sensors for automotive air conditioners, and sensors that control the temperature of air and fuel mixtures.
Polyphenylene sulfide (PPS) has excellent heat resistance. It has been used by the United States UL for continuous use at a temperature of 200 ° C to 240 ° C. The high-temperature heat distortion temperature is above 260 ° C, and it has excellent solder resistance. PPS is a high level of V-0 / 5V in the UL94 flammability test without the addition of a flame retardant.
PPS has excellent chemical resistance comparable to PTFE machining (polytetrafluoroethylene), and currently no solvent has been found to dissolve PPS below 200 ° C. PPS also features high mechanical strength, high rigidity, good dimensional stability, and low water absorption. By filling lubricants such as carbon fiber and fluororesin, friction and wear characteristics can be greatly improved. PPS has excellent processability and good fluidity, and can be used for thin-wall, long-flow injection molding.
PPS has a wide range of applications. In the field of electrical and electronic parts, it is used as various connectors, coil tubes, solid state relays, motor drums, capacitor shields, magnetic sensor induction heads, capacitors, etc. Various precision parts processing, such as cameras, tachometers, gears, watches, copier parts, computer parts, CD parts; in the automotive field, it is used as exhaust treatment device parts, connectors, carburetor, oil distributor parts, radiator parts, Steering rod end support, lamp reflector, lamp holder, brake parts, clutch parts, temperature sensor, rotating parts, oil pump, etc.
PPS was first industrialized by the American Phillips Petroleum Company in 1973 and launched on the market under the trade name “Ryton”. In the 1970s, Shanghai, Tianjin, Guangzhou, Sichuan and other places in China carried out research and development work on the production and application of PPS. Among them, the research institute with early and strong strength is the Material Research Institute of Sichuan University, which has obtained many national patents.
In 2003, the company started a 1,000-ton polyphenylene sulfide plant in the Demonstration Park of Chinese Patent Technology Industrialization in Deyang City, Sichuan Province, marking a significant progress in the Chinese polyphenylene sulfide industry. At present, China’s polyphenylene sulfide production capacity is about 2500t / a. The main production units are Sichuan Huatuo Technology Co., Ltd., Tianjin Synthetic Materials Industry Research Institute, Sichuan Changshou Chemical General Factory, Guangzhou Chemical Research Institute, Guangzhou Chemical Reagent Factory, Sichuan. Special Engineering Plastics Plant, Beijing Research Institute of Chemical Industry, etc. Except for Sichuan Huatuo, the vast majority are small.
Polysulfone (PSF) is a transparent, hydrolytically stable plastic with good dimensional stability and good deformation stability at room temperature; it has outstanding thermal stability, excellent mechanical properties, outstanding long-term creep resistance, and long life. The mechanical properties of time use remain unchanged. It has excellent resistance to moist heat and aging, and its life is at least 12 years under 145 ℃ steam. And it is also an excellent variety of flame resistance, radiation resistance, and chemical resistance.
At present, electronics and electrical appliances are big consumers of PSF. The development of electronics and electronics toward small size, light weight, and high temperature resistance has promoted the growth of PSF consumption. PSF can be used to make various electrical parts, such as contactors, transformer insulators, thyristors, insulating sleeves, coil bobbins, terminals, printed circuit boards, various sleeves, covers, film and television system parts, capacitor films, Brush holder, alkaline battery box, etc.
In the field of aerospace and automotive manufacturing, PSF is suitable for making protective cover elements, electric gears, battery covers, electronic ignition components, lighting components, aircraft interior parts and aircraft external parts, and spacecraft outer protective covers.
At present, the global PSF production capacity is about 35,000 tons, and the total consumption is 30,000 tons. China’s PSF has a production capacity of about 1,500 tons / year, and its output remains at about 1,000 tons / year. China has very few PSF resin grades, which are mainly used in medical equipment, food processing machinery, electronic instruments, textiles and other industries. Compared with foreign countries, the production process, including monomer synthesis, polymerization, post-processing recovery and so on, still needs to be improved and improved, and its application in the fields of automotive, aerospace and other fields needs to be further promoted.
Polyethersulfone (PES) is a crystalline resin that maintains stable mechanical properties over a wide temperature range; its creep resistance is an excellent one among thermoplastic resins at temperatures below 180 ° C; it has a size Good stability, impact resistance, excellent chemical resistance, excellent flame resistance, etc.
PES can not only be processed by extrusion, injection, compression molding, blow molding, blistering and making into foam, but also can perform secondary processing such as coating, ultrasonic welding, mechanical processing, solvent adhesive coating, etc.
Because PES has excellent dimensional stability, heat resistance, flame resistance, resistance to solder, resistance to various cleaning agents, can be embedded in metal parts, and good adhesion to epoxy resin, etc., it can be used as H-level insulation materials. In the field of electronics and electronics, it is mainly used for processing bobbin, external base of potentiometer, printed circuit board, push-button switch, thyristor insulator, insulator of power tool motor, DIP switch, various plug-in parts, etc. Medical devices often require materials that are transparent, strong, and capable of withstanding various sterilization processes.
PES can meet these requirements well and is widely used in the preparation of medical equipment such as contact lenses, sterilization containers, gas mask parts, dental mirror holders, respirators, blood pressure inspection tubes, surgical containers and syringes.
PES is a special engineering plastic variety developed by British ICI company in 1972. The 300-ton / year unit developed by Jida New Material’s existing independent technology was put into production in 2002.