Polybutylene terephthalate  

Polybutylene terephthalate is a chemical compound, modified terephthalate polymer, a copolymer of 1,4-butanediol and dimethyl terephthalate or terephthalic acid. Terephthalic acid is an aromatic carboxylic acid used in the production of polyester fibres. Safety. Cases of allergy to terephthalic acid have been reported. What it is used for and...