Polyester fiber is a synthetic fiber obtained by spinning polyester, which is condensed from organic dicarboxylic acids and diols. The polyester fibers produced in large quantities through industrialization are made of polyethylene terephthalate, which is marketed as polyester in China. It is currently the largest variety of synthetic fibers. Introduction to Polyester Fabric Raw Material - Polyester is an important variety of synthetic fibers and is the trade name of polyester fibers in China. It is a fiber forming polymer called polyethylene terephthalate (PET), which is made from purified terephthalic acid (PTA) or dimethyl terephthalate (DMT) and ethylene glycol (EG) through esterification, ester exchange, and condensation reactions. The fibers are produced by spinning and post-treatment. Controversy over standard release: According to the national standard release announcement, GB/T4146.1-2009 "Chemical Fibers for Textiles Part 1: Generic Names" was officially implemented from January 1, 2010. After the implementation of the standard, most of the testing reports issued by the testing institutions began to use "polyester fiber" instead of the previous "polyester", which caused concern and confusion among enterprises. Some enterprises even believed that the new standard had cancelled the name "polyester" for this fiber. Now, the following is an explanation of this issue: the definition of "polyester fiber" itself has not only referred to "polyester", but also includes fibers composed of linear macromolecules containing more than 85% terephthalate in all molecular chains. It was only in fz/T01053-2007 "Identification of Textile Fiber Content" that "polyester fiber (polyester)" appeared, which equated "polyester fiber" with "polyester". In fact, "polyester" is just one type of "polyester fiber". In GB/T4146.1-2009 "Chemical Fibers for Textiles Part 1: Generic Names", "polyester fiber" includes three types of fibers: "polyethylene terephthalate (PET)", "polytrimethylene terephthalate (PTT)", and "polybutylene terephthalate (PBT)". In practical testing, it is difficult to distinguish these three types of fibers through ordinary methods. Therefore, according to the standard GB/T4146.1-2009 "Chemical Fibers for Textiles Part 1: Generic Names", a "polyester fiber" report will generally be issued. Only when the client explicitly requests and the sample can be determined to be "polyethylene terephthalate", can the testing agency issue a "polyester" report.