| abstract |
The present invention aims to provide a method for producing polybutylene terephthalate (PBT) with an excellent color using biomass-derived 1,4-butanediol (BG). The invention relates to a method for producing PBT comprising a step of subjecting a diol component containing raw material 1,4-BG having a nitrogen content of 0.01 to 50 ppm by mass and a dicarboxylic acid component to esterification or ester-exchange reaction, and a polycondensation reaction step for obtaining PBT from the reactant, wherein the content of gamma butyrolactone in the raw material 1,4-BG is 1 to 100 ppm by mass. |