DYE-EXTRACTION DEPOLYMERIZATION METHOD OF DYED POLYESTER FIBER

摘要

PROBLEM TO BE SOLVED: To provide a dye extraction reaction tank apparatus that permits acquisition of a depolymerization solution containing a bis-β-hydroxyalkyl terephthalate (BHAT) from a dyed polyester fiber by extracting dyes from dyed polyester fiber waste using an extraction solvent comprised of xylene and an alkylene glycol and subsequently subjecting the dye-extracted polyester fiber to a depolymerization reaction using an alkylene glycol in the presence of a depolymerization catalyst in the same reaction tank.

SOLUTION: The dye-extraction depolymerization method for obtaining the depolymerization solution containing the bis-ω-hydroxyalkyl terephthalate (BHAT) comprises extracting dyes from a dyed polyalkylene terephthalate fiber using the extraction solvent in a reaction tank where wire netting for effecting solid/liquid separation is arranged, drawing out the extraction solvent to the outside of the reaction tank by the solid/liquid separation thereby obtaining a dye-extracted polyalkylene terephthalate fiber and subsequently subjecting the dye-extracted polyalkylene terephthalate fiber to the depolymerization reaction in the presence of the depolymerization catalyst and the alkylene glycol in the same reaction tank.

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