METHOD FOR PRODUCING BIS-(2-HYDROXYETHYL)TEREPHTHALATE AND METHOD FOR PRODUCING RECYCLED POLYETHYLENE TEREPHTHALATE

摘要

[Problem] To provide a method for producing bis-(2-hydroxyethyl)terephthalate (BHET), the method being capable of simply producing a BHET with high purity from a colored polyester waste. [Solution] A method for producing a BHET according to the present invention comprises: a depolymerization step for mixing a polyester waste colored by a pigment, with a monoethylene glycol and a depolymerization catalyst, and depolymerizing the polyester waste to obtain a depolymerized product containing a crude colored BHET; a pigment decomposition/removal step for adding a pigment decomposition agent to the depolymerized product and cooling and centrifuging the resultant mixture, thereby separating extracted solids and the decomposed product of the pigment and removing at least a portion of the decomposed product from the depolymerized product; a concentration step for removing a low boiling-point component containing monoethylene glycol from the depolymerized product from which at least a portion of the decomposed product has been removed, and concentrating the crude BHET; and a collection step for collecting, by distillation, BHET from the concentrated crude BHET to obtain a BHET having higher purity than the crude BHET.