| abstract |
To establish an efficient and economical useful component recovery method capable of recovering high purity useful components from a dyed polyester fiber. n A method for recovering useful components from a dyed polyester fiber, includes a dye extraction step, a solid liquid separation step, a depolymerization reaction step, an ester interchange reaction step, and a useful component separation step, for recovering useful components from the dyed polyester fiber, wherein the dye extraction step includes a step of extracting and removing a dye at the glass transition temperature of the polyester or higher and at 220° C. or less with a xylene extracting solvent and an alkylene glycol extracting solvent in combination. |