PBT is the abbreviation of polybutylene terephthalate. PBT high elastic yarn has excellent elastic recovery and stability, elasticity is better than nylon, chemical resistance is better than spandex, carrier-free dyeing can be carried out at normal temperature and pressure, dyeing fastness is high, dimensional stability is good, pilling resistance and antistatic performance are good, and the price is much lower than spandex. The fiber can be widely used in knitting and weaving fabrics, and can replace spandex to produce coated yarn. Fabrics for high-end sportswear, swimsuits and casual clothes. PBT high elastic yarn has a broad application prospect in the fields of sanitary materials, clothing and so on, and is a highly competitive new product in the future elastic fiber market. 1 and PBT have good durability, dimensional stability and good elasticity, and the elasticity is not affected by temperature. 2.PBT fiber and its products have soft hand feel, good hygroscopicity, wear resistance and fiber curl, excellent tensile elasticity and compression elasticity, superior elastic recovery rate to polyester fiber, special flexibility under dry and wet conditions, and the elasticity is not affected by environmental temperature changes, and the price is much lower than that of spandex fiber. 3.PBT has good dyeing performance and can be scoured with common disperse dyes under normal pressure without carrier. The dyed fiber has bright color, excellent color fastness and chlorine resistance. 4。 Excellent chemical resistance, light resistance and heat resistance. 5。 PBT/PET composite fiber has fine three-dimensional crimp, superior resilience, soft handle and excellent dyeing performance, and is an ideal wool-like and down-like raw material, which is comfortable to wear.