What is "polybutylene terephthalate"

n. (context organic chemistry English) A plastic used industrially as an electrical insulator

Polybutylene terephthalate (PBT) is a thermoplastic engineering polymer that is used as an insulator in the electrical and electronics industries. It is a thermoplastic (semi-)crystalline polymer, and a type of polyester. PBT is resistant to solvents, shrinks very little during forming, is mechanically strong, heat-resistant up to (or with glass-fibre reinforcement) and can be treated with flame retardants to make it noncombustible.

PBT is closely related to other thermoplastic polyesters. Compared to PET ( polyethylene terephthalate), PBT has slightly lower strength and rigidity, slightly better impact resistance, and a slightly lower glass transition temperature. PBT and PET are sensitive to hot water above (140 °F). PBT and PET need UV protection if used outdoors, and most grades of these polyesters are flammable, although additives can be used to improve both UV and flammability properties.