Polybutylene terephthalate (PBT) is a crystalline polyester formed by the trans-esterification of dimethyl terephthalate (DMT) and 1,4-butanediol to form bis-hydroxbutyl terephthalate (bis-HBT). Pure terephthalic acid (PTA) can also be used instead of DMT, although DMT remains the preferred raw material. PBT, also known as polytetramethylene terephthalate (PTMT), was originally developed and introduced by Celanese in 1970. The material was intended to replace thermosetting materials such as diallyl phthalate (DAP), alkyd, and phenolic resins, which had been used particularly in automotive electrical systems and interconnections. PBT has successfully competed against and replaced these materials in high performance transportation applications. PBT offers a high continuous use temperature compared to other thermoplastics, excellent electrical properties, and can easily be flame retarded. In addition to polyester homopolymers such as PBT, thermoplastic polyester copolymers may also be formulated by reacting more than one dibasic acid and glycol. Copolyesters tend to crystallize less rapidly than PBT and may have a depressed melting point. A few PBT copolymer flame resistant, injection moldable grades are sold commercially, whereas PET based copolymers have had success in packaging applications. The strengths and weaknesses of PBT's properties are illustrated in the figure below. This report examines the process technology, production economics, and market outlook for PBT. PBT producers, users, and raw material suppliers will find this report of value for planning purposes. | 
