Method for recovering useful components from dyed polyester fiber
First Claim
1. A method for recovering useful components from a dyed polyester fiber, comprising a dye extraction step, a solid liquid separation step, a depolymerization reaction step, an ester interchange reaction step, and a useful component separation step, the dye extraction step being a step of extracting and removing a dye at the glass transition temperature of the polyester or higher and at 220°
- C. or less by an extracting solvent including xylene and alkylene glycol from the dyed polyester fiber, the solid liquid separation step being a step of separating a dye-extracted polyester fiber and a dye-containing extracting solvent after the dye extraction step, the depolymerization reaction step being a step of allowing the dye-extracted polyester fiber to undergo a depolymerization reaction with alkylene glycol in the presence of a depolymerization catalyst, thereby to obtain a depolymerized solution containing bis-ω
-hydroxy alkylene terephthalate, the ester interchange reaction step being a step of allowing the depolymerized solution to undergo an ester interchange reaction by an ester interchange catalyst and methanol, and the useful component separation step being a step of separating and recovering dimethyl terephthalate and alkylene glycol from the ester interchange reaction product mixture obtained in the ester interchange reaction step.
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Abstract
To establish an efficient and economical useful component recovery method capable of recovering high purity useful components from a dyed polyester fiber.
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.
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12 Claims
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1. A method for recovering useful components from a dyed polyester fiber, comprising a dye extraction step, a solid liquid separation step, a depolymerization reaction step, an ester interchange reaction step, and a useful component separation step, the dye extraction step being a step of extracting and removing a dye at the glass transition temperature of the polyester or higher and at 220°
- C. or less by an extracting solvent including xylene and alkylene glycol from the dyed polyester fiber, the solid liquid separation step being a step of separating a dye-extracted polyester fiber and a dye-containing extracting solvent after the dye extraction step, the depolymerization reaction step being a step of allowing the dye-extracted polyester fiber to undergo a depolymerization reaction with alkylene glycol in the presence of a depolymerization catalyst, thereby to obtain a depolymerized solution containing bis-ω
-hydroxy alkylene terephthalate, the ester interchange reaction step being a step of allowing the depolymerized solution to undergo an ester interchange reaction by an ester interchange catalyst and methanol, and the useful component separation step being a step of separating and recovering dimethyl terephthalate and alkylene glycol from the ester interchange reaction product mixture obtained in the ester interchange reaction step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- C. or less by an extracting solvent including xylene and alkylene glycol from the dyed polyester fiber, the solid liquid separation step being a step of separating a dye-extracted polyester fiber and a dye-containing extracting solvent after the dye extraction step, the depolymerization reaction step being a step of allowing the dye-extracted polyester fiber to undergo a depolymerization reaction with alkylene glycol in the presence of a depolymerization catalyst, thereby to obtain a depolymerized solution containing bis-ω
Specification