The polyester in polyester flannel fabric is actually polyester fiber. It is a synthetic fiber obtained by spinning polyester formed by polycondensation of organic dibasic acid and diol, referred to as PET fiber, which belongs to polymer compound.

Polyester (PET) fiber is a synthetic fiber spun from each link in the macromolecular chain through an ester group to form a fiber-forming polymer. my country abbreviates fibers with a polyethylene terephthalate content of more than 85% as polyester, and there are many foreign trade names. There are many fibers discovered in the early days, so PET fiber can be said to be a late-developed fiber among large varieties of synthetic fibers.

With the development of organic synthesis, polymer science and industry, a variety of practical PET fibers with different characteristics have been developed in recent years. Such as polybutylene terephthalate (PBT) fibers and polytrimethylene terephthalate (PTT) fibers with high elasticity, and fully aromatic polyester fibers with ultra-high strength and high modulus: the so-called The "polyester fiber" usually refers to polyethylene terephthalate fiber.

However, these characteristics of polyester and flannel of polyester flannel fabric are very suitable for home textile fabric , so in addition to clothing, it is also used in home textiles.