Polyethylene terephthalate (PET), chemical formula (C10H8O4)n, is made from dimethyl terephthalate and glycol transesterification or esterification of terephthalate and glycol to synthesize dihydroxyethyl terephthalate, and then polycondensation reaction. It is a crystal type saturated polyester, which is a milky white or light yellow, highly crystalline polymer with smooth and glossy surface. It is a common resin in life, which can be divided into APET, RPET and PETG. It has excellent physical and mechanical properties in a wide range of temperatures, up to 120â??, and excellent electrical insulation. Even at high temperature and high frequency, its electrical properties are still good, but it has poor corona resistance, creep resistance, fatigue resistance, friction resistance and dimensional stability. Advantages: 1. Good mechanical properties, impact strength is 3~5 times that of other films, good folding resistance. 2 oil resistance, fat resistance, dilute acid resistance, dilute alkali resistance, resistance to most solvents. 3. Can be used in the temperature range of 55-60â?? for a long time, short-term use can resist 65â?? high temperature, can resist -70â?? low temperature, and high and low temperature has little impact on its mechanical properties. 4. Low permeability of gas and water vapor, and excellent resistance to gas, water, oil and odor. 5. High transparency, can block UV, good luster. 6. Non-toxic, tasteless, good health and safety, can be directly used for food packaging.