Polyethylene terephthalate (PET)
1: Overview
In 1946, the United Kingdom issued the first patent for the preparation of PET, and in 1949 The British ICI formula completed pilot testing in 2001, but after the American DuPont Company purchased the patent, it established a production device in 1953, becoming the first to achieve industrial production in the world. In the early days, PET was almost always used for synthetic fibers (commonly known as polyester and deliang in my country). Since the 1980s, PET has made breakthrough developments as an engineering plastic, and nucleating agents and crystallization accelerators have been developed successively. Currently, PET, together with PBT, is used as a thermoplastic polyester and has become one of the five major engineering plastics.
PET is divided into fiber-grade polyester chips and non-fiber-grade polyester chips. ① Fiber-grade polyester is used to make polyester short fiber and polyester filament, and is the raw material supplied to polyester fiber companies for processing fibers and related products. Polyester is the most produced variety of chemical fibers. ② Non-fiber grade polyester is also used in bottles, films, etc., and is widely used in the packaging industry, electronic appliances, medical and health, construction, automobiles and other fields. Among them, packaging is the largest non-fiber application market for polyester, and it is also the fastest growing market for PET. Fast field.
Advantages of PET as a packaging material:
1. It has good mechanical properties, the impact strength is 3 to 5 times that of other films, and it has good folding resistance.
2. Resistant to oil, fat, acid, dilute alkali, and most solvents.
3. It has excellent high and low temperature resistance and can be used in the temperature range of 120℃ for a long time. It can withstand high temperatures of 150℃ and low temperatures of -70℃ for short-term use, and it can be used at high and low temperatures. Mechanical properties are minimally affected.
4. The permeability of gas and water vapor is low, and it has excellent gas, water, oil and odor barrier properties.
5. High transparency, can block ultraviolet rays, and has good gloss.
6. Non-toxic, tasteless, hygienic and safe, and can be directly used for food packaging.