Polyethylene terephthalate (PET) is a thermoplastic polymer widely used in daily life and industrial applications. Its chemical formula is COC6H4COOCH2CH2O. It is produced by the transesterification of dimethyl terephthalate with ethylene glycol, or by the esterification of terephthalic acid with ethylene glycol to form bis(2-hydroxyethyl) terephthalate, followed by polycondensation. PET is a crystalline saturated polyester, appearing milky white or light yellow with a highly crystalline structure, a smooth and glossy surface.
PET exhibits excellent physical and mechanical properties over a wide temperature range: its continuous use temperature can reach 120°C, short-term use can withstand temperatures up to 150°C, and it can also resist low temperatures down to -70°C. It has good electrical insulation properties, maintaining stable electrical performance even at high temperatures and high frequencies, though its corona resistance is relatively poor. In addition, PET also features good creep resistance, fatigue resistance, wear resistance, and dimensional stability.
PET materials decompose under the action of strong acids, strong alkalis, and steam, but they are resistant to organic solvents and have good weatherability. However, PET has a slow crystallization rate, making molding processing relatively difficult, with high mold temperatures and long production cycles, and its impact performance also needs improvement. To improve its processability and physical properties, PET is generally modified through reinforcement, filling, and blending methods, such as adding glass fibers to enhance its rigidity, heat resistance, chemical resistance, electrical properties, and weatherability.
PET sealing rings are an important application form of PET materials, playing a key role in various industries thanks to their excellent physical and mechanical properties and chemical stability.
Food Packaging Industry
PET materials are non-toxic, odorless, and have good hygienic safety, making them suitable for direct use in food packaging. Therefore, PET sealing rings are widely used in food packaging machinery, ensuring the safety and hygiene of food during processing, storage, and transportation.
Medical Equipment Industry
PET materials are resistant to biological aging, making them suitable for medical packaging materials, infusion sets, hemodialysis machines, and more. PET sealing rings are used in medical equipment to seal various liquid and gas pipelines, ensuring the safety and reliability of medical supplies.
Chemical Industry
PET materials are resistant to oils, fats, oleic acid, dilute alkalis, and most solvents, making them suitable for sealing chemical equipment. PET sealing rings are used in chemical equipment to seal corrosive media and withstand high-temperature, high-pressure environments, ensuring stable equipment operation.
Automotive Industry
In the automotive sector, PET sealing rings are used to seal liquid and gas pipelines in components such as engines and gearboxes, preventing leaks and improving vehicle performance and safety.
Electronics & Electrical Industry
PET films are widely used in the manufacturing of capacitors, insulating sheets, display backlight modules, and other electronic products due to their excellent insulation, heat resistance, and dimensional stability. PET sealing rings are used in electronic and electrical equipment to seal various circuit boards and connectors, ensuring normal equipment operation.
In conclusion, polyethylene terephthalate (PET) is an important polymer material that plays an irreplaceable role in multiple fields. As one of its key applications, PET sealing rings are widely used in industries including food packaging, medical equipment, chemical processing, automotive, and electronics, providing strong support for the stable operation of equipment and product quality in these sectors.