PET is a milky white or yellowish highly crystalline polymer with a smooth and glossy surface. Creep resistance, fatigue resistance, friction resistance and dimensional stability, small wear and high hardness, has the biggest toughness of thermoplastic: good electrical insulation, little influence by temperature, but poor corona resistance. Non-toxic, weatherproof, stable, low water absorption, weak acid and organic solvent resistance, but not resistant to hot water immersion, alkali.PET resin glass transition temperature is higher, crystallization rate is slow, molding cycle is long, molding cycle is long, Large shrinkage, poor dimensional stability, brittle crystallization, low heat resistance, etc. . In addition to the properties of PBT, the improved PET, which is reinforced by nucleating agent, crystallization agent and glass fiber, also has the following characteristics. 1. Thermal deformation temperature and long-term service temperature are the highest in thermoplastic engineering plastics. Because of the high heat resistance, the reinforced PET is impregnated with 10s in 250 ℃ solder bath, and hardly deformed or discolored. It is especially suitable for preparing the electronic and electrical parts of tin welding. The flexural strength is 200MPa, the elastic modulus is up to 4000MPa, the creep resistance and fatigue resistance are also very good, the surface hardness is high, the mechanical property is close to that of thermosetting plastics .4. Due to the production of ethylene glycol for PET The price of PET resin and reinforced PET is the lowest in engineering plastics and has a high performance and price ratio because it is almost half cheaper than the price of butanediol used in the production of PBT.