Application Fields of Polyester Film

I. Introduction to Polyester Film

Polyester film, also known as PET film (including optical sheets, polyester film, photosensitive paper, Mylar, benzo-tin film, cellophane, and release film), is a film material made from polyethylene terephthalate (PET). It is produced by an extrusion process to form thick sheets, which are then biaxially stretched. In China, polyester films (such as eco-friendly PET films, PET sheets, and milky white films for printing and packaging) are widely used in industries such as fiberglass, construction, printing, and healthcare.  

China has successfully developed a PET twist film, which is non-toxic, colorless, transparent, moisture-resistant, airtight, soft, strong, resistant to acids, alkalis, oils, and solvents, and tolerant of high and low temperatures. As a non-toxic, transparent, and recyclable material, it is mainly used for packaging various beverages, mineral water, and other products. It is currently one of the most widely used packaging materials globally. Polyester film, a type of polymer plastic film, is gaining increasing popularity among consumers due to its excellent comprehensive properties. However, as China's production capacity and technological level still cannot fully meet market demand, part of the supply still relies on imports.  

II. Properties of Polyester Film  

PET is a high polymer formed by the dehydration condensation reaction of ethylene glycol terephthalate, which is derived from the esterification reaction of terephthalic acid and ethylene glycol. PET is a milky white or light yellow, highly crystalline polymer with a smooth and glossy surface. It possesses excellent properties (heat resistance, chemical resistance, high toughness, electrical insulation, safety, etc.) and is cost-effective, making it widely used in fibers, films, engineering plastics, polyester bottles, and other applications.  

PET exhibits excellent physical and mechanical properties across a wide temperature range, with a long-term service temperature of up to 120°C. It has excellent electrical insulation, maintaining good electrical properties even at high temperatures and high frequencies, although it has poor corona resistance. It is non-toxic, weather-resistant, and chemically stable, with good creep resistance, fatigue resistance, friction resistance, and dimensional stability. It has a low water absorption rate, is resistant to weak acids and organic solvents, but is not resistant to hot water immersion or alkalis. Typically, PET is a colorless, transparent, and glossy film (color can be added via additive particles). It has excellent mechanical properties, high rigidity, hardness, and toughness, and is resistant to puncture, friction, high and low temperatures, chemicals, oils, and has good airtightness and aroma retention. It is a commonly used base material for barrier composite films, though it has poor corona resistance.