What are special engineering plastics?
Special engineering plastics refer to a class of engineering plastics with high comprehensive performance and long-term use temperature above 150 ¡æ, mainly including polyphenylene sulfide (PPS), polyimide (PI), polyether ether ketone (PEEK), liquid crystal Polymer (LCP) and polysulfone (PSF). Special engineering plastics have unique and excellent physical properties and are mainly used in high-tech fields such as electronic and electrical and special industries.
The development history of special engineering plastics
Special engineering plastics are a new generation of high-performance polymer materials promoted by the social needs of the arms race during the Cold War between the United States and the Soviet Union since the 1960s and the early 1980s. In the early days, it was called high temperature resistant polymer material (relative to engineering plastics). At present, it is usually called Super Engineering Plastics or High Performance Polymer. Since the introduction of polyimide (PI) in the 1960s to the commercialization of PEEK in the early 1980s, nearly 20 During the years, the main varieties successfully developed and industrialized are:
1. Polyimide (PI);
2. Polyamideimide (PAI);
3. Polyetherimide (PEI);
4. Polyarylate (U-polymer);
5. Polyphenylene sulfide (PPS);
6. Polysulfone (PSF)
7. Polyethersulfone (PES);
8. Polyether ether ketone (PEEK) and so on.
The development history of special engineering plastics
1) Physical properties:
a. High heat resistance level (generally defined as UL temperature index above 150¡æ);
b. High mechanical strength (generally 2~4 times of general-purpose plastic);
c. Excellent comprehensive performance (such as radiation resistance, temperature resistance, weather resistance).
d. Extraordinary stability and performance beyond traditional polymers.
2) Processing technology:
a. High processing temperature (generally 300~400¡æ);
b. High injection pressure (usually 120MPa~160MPa);
c. The mold must be heated (contrary to the cooling of general plastics);
d. Hot runner is better.
Application of special engineering plastics
A typical feature of special engineering plastics is that the production volume is relatively small and the application is special. This type of material was originally born to meet the needs of national defense industry or human scientific exploration. At present, its application is shifting to civilian use.
1. Aerospace
Due to the special use environment of the spacecraft, its structural materials are required to have the characteristics of light weight, high strength, high temperature resistance, and high flame retardancy. Materials such as PI, PEEK, PPS and polyamideimide have high heat distortion temperature and continuous use temperature, so they are most widely used in the aviation industry.
2. Electronic information field
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Application of special engineering plastics in the field of electronic information. mainly includes:
(1) Electronic components (such as connectors, sockets, insulated coils and gears, etc.);
(2) Integrated circuit (IC) packaging materials and lead-free soldering materials;
(3) Advanced communication components (such as optical waveguide materials, mobile phone components, etc.). Due to the excellent comprehensive properties of special engineering plastics (such as being able to maintain good dimensional stability even in a thin state, etc.), many mobile communication manufacturers have turned their attention to special engineering plastics during the development of their new generation of mobile communication equipment. .
(4) Another important application of special engineering plastics in the microelectronics industry is as an IC assembly material.
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3. Medical and health field
In recent years. Synthetic polymer materials are widely used as biomedical materials (such as artificial organs, urinary catheters, endoscopes, etc.). Because medical polymer materials can have different physical and chemical properties (such as resistance to biological aging, as long-term implant materials, easy processing and disinfection, etc.) by controlling their composition and structure, they have received general attention from all over the world and become biological Among the materials, the most widely used and the most used variety. It is easy to process, can withstand repeated disinfection treatments, and is resistant to hydrolysis. Therefore, it is gradually applied to the production of medical devices, drug delivery systems and artificial bones.
4. Energy field
The application of high-performance battery manufacturing is one of the most typical applications of special engineering plastics in the energy field. The fuel cell is a high-efficiency power generation device that directly converts the chemical energy of the fuel into electrical energy through an electrochemical reaction without burning.
