Pet can be processed into fiber, film and plastic products. Polyester fiber is an important variety of synthetic fiber, mainly used for wearing. The film is generally 4-400 μ m thick, with high strength, good dimensional stability and good chemical and dielectric resistance. It is widely used as a support for making various tapes and magnetic cards. 90% of the tape substrate is made of PET film, 80% of which is used as computer tape. The film is also used in the production of photosensitive materials, as the film base of photographic film and X-ray film, as the insulating materials of electric motors, transformers and other electronic appliances, as well as various packaging materials.
Due to the rapid crystallization speed of PET melt when it is cooled and the difficulty of forming, the mold temperature must be kept above 140 ℃ to obtain the product with good performance, otherwise the product will be brittle. Therefore, pet has not been used as thermoplastic engineering plastics for a long time. With the development of science and technology, the above difficulties have been overcome by adopting new polycondensation catalyst system or co polycondensation process, strengthening with glass fiber, or controlling the crystal structure and preparing high molecular weight polyester. Pet has been increasingly used in beverage bottles and glass fiber reinforced plastics. The advantages of polyester bottle are light weight (only 1 / 9-1 / 15 of the weight of glass bottle), high mechanical strength, not easy to break, easy to carry and use, good transparency, shiny surface, non-toxic, air tightness, good freshness, less energy consumption in production of polyester bottle, renewable use of waste bottle. It is also used to make packaging bottles for food oil, condiment, sweet food, medicine, cosmetics and alcoholic beverages. Not only transparent bottles but also colored bottles are produced, and polyester and other resin composite bottles are being developed. In 1984, DuPont company developed a super toughness glass fiber reinforced pet, which has excellent rigidity, impact toughness and heat resistance, good melt flow, easy to be processed into products with complex shape, short molding cycle, good coloring, and mold temperature above 80 ℃ to produce products with good surface gloss. It is mainly used for automobile shell, bumper, steering wheel, sports equipment, electrical appliances, bathtub, bulletproof armor, hull and excellent building materials.