Engineering plastics refer to industrial plastics used as industrial parts or housing materials, and are plastics with excellent strength, impact resistance, heat resistance, hardness and aging resistance. The Japanese industry defines it as "high-performance plastics that can be used for structural and mechanical parts, with heat resistance above 100°C, and are mainly used in industry." Its properties include:
1. Thermal properties: glass transition temperature (Tg) and melting
point (Tm); high heat distortion temperature (HDT); high long-term use
temperature (UL-746B); large use temperature range; small thermal
expansion coefficient.
2. Mechanical properties: high strength, high mechanical modulus, low
creep, strong wear and fatigue resistance.
3. Others: chemical resistance, electrical resistance, flame resistance,
weather resistance, and good dimensional stability.
Those regarded as general engineering plastics include polycarbonate (PC), polyamide (nylon), polyacetal (POM), modified polyphenylene ether (modified PPE), polyester (PETP, PBTP), polyphenylene sulfide ( PPS), polyarylate, and thermosetting plastics include unsaturated polyester, phenol plastic, epoxy plastic, etc. Their basic characteristics are that the tensile strength is more than 50Mpa, the tensile strength is more than 500kg/cm, the impact resistance is more than 50J/m, the flexural modulus is 24000kg/cm, the load bending temperature is more than 100℃, and the hardness and aging properties are excellent.
If polypropylene improves its hardness and cold resistance, it can also be included in the scope of engineering plastics. In addition, it also includes special fluorine plastics with weak strength and excellent heat and chemical resistance, silicon melting compounds with excellent heat resistance, and polyamideimide, polyimide, Polybismaleimide, Polysufone (PSF) , PES, acrylic plastic, modified melamine plastic, BTResin, PEEK, PEI, liquid crystal plastic, etc.
Engineering plastics are polymers of exhibit outstanding mechanical properties (strength, dao creep resistance, strong impact resistance, fatigue strength and wear resistance) in a large temperature range. Therefore, they are particularly suitable for use as structural and machined parts, instead of other structural materials (mostly metal). There are polyvinyl chloride PVC, acrylic PMMA, QUADRANT ordinary plastic products, nylon products PA, polycarbonate products PC, ultra-high molecular weight polyethylene U-PE polyformaldehyde products POM, etc. The advantages of these engineering plastics are insulation, heat insulation, Design flexibility, easy molding, multiple colors, etc.
