Polyester lanyard, a general term for polymers obtained by polycondensation of polyols and polybasic acids. It mainly refers to polyethylene terephthalate (PET), and it is customary to include linear thermoplastic resins such as polybutylene terephthalate (PBT) and polyarylate. It is a kind of engineering plastic with excellent performance and wide application. It can also be made into polyester fiber and polyester film. Polyesters include polyester resins and polyester elastomers. The polyester resin further includes polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyarylate (PAR), and the like. The polyester elastomer (TPEE) is generally polymerized from dimethyl terephthalate, 1,4-butanediol, and polybutanol, and the segment includes a hard segment portion and a soft segment portion, and is a thermoplastic elastomer.