PET fiber, also known as polyethylene terephthalate fiber, is often called polyester in China. At present, PET fibers are mainly prepared by direct esterification of terephthalic acid (PTA) and ethylene glycol (EG) or transesterification of dimethyl terephthalate (DMT) and ethylene glycol (EG).
The longitudinal section of PET fiber is similar to that of PTT fiber, and the cross-section presented under the microscope is round, the longitudinal thickness is relatively uniform, the hairiness is less, and the surface is smooth. The molecular formula of PET fiber is [-OC-Ph-COOCH2CH2O-]n, and the single group is composed of one benzene ring, two ester groups and two methylene groups. Due to the presence of benzene ring in the PET molecule, it needs to be stretched after the traditional melt spinning, so that it can be quickly crystallized, so that the fiber orientation and crystallinity can be higher, and the PET fiber produced by this has high strength, good elasticity, excellent heat setting performance, good heat resistance, acid and alkali resistance and other properties.
Polyester is widely used in clothing, decoration, and industrial fields due to its simple processing and inexpensiveness. In the field of clothing, the fabric made of PET is easy to wash and dry, with the title of "washable and wearable", and the ester bonds in its molecule have strong antioxidant capacity, which is not easy to be damaged by detergents and soap and other products, and PET fibers are not easy to be attacked by microorganisms, so the fabric has good durability. Polyester fabrics are stable in size, crisp and resistant to shrinkage after heat setting, and can be used to make shirts, men's suit pants, outerwear and jackets. The disadvantages of polyester are mainly due to the tight molecular arrangement and lack of hydrophilic groups, so the dyeability, hygroscopicity, and antistatic properties are poor, and the product is flammable.