Mainly used in bottle-grade polyester (widely used in the packaging of various drinks, especially carbonated drinks), polyester film (mainly used in packaging materials, films and adhesive tapes, etc. ) and polyester for chemical fiber. The earliest history of polyester series products can be said to be that Carothers of DuPont Company in the United States studied the polycondensation reaction of aliphatic dibasic acids and ethylene glycol at 1928, and made fibers from polyester at the earliest. 193 1 autumn, carothers officially published his research results in the American Chemical Society. Fiber has the luster of silk, and its strength and elasticity are equivalent to that of silk, but it has low melting point, easy hydrolysis, alkali resistance and no practical value. But this study proves for the first time that polyester can be made into fibers. Inspired by the work of Carothers, winfield and Dixon of Printing and Dyeing House Association (CPA) continued to study polyester in 194 1, and CPA obtained the patent right in 1942. It can be said that polyester (PET) was the earliest industrialized production in Britain in 1949. Because of its excellent wear resistance and high strength, it has become the largest variety of synthetic fibers.