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US 12,742,053 B2Granted
Method for decolorizing polyester and method for depolymerising polyester comprising the same
AssigneeKolon Industries, Inc.
InventorsJoonyoung Yoon, Hongkwan Park, Haelim Cho
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Abstract
Provided is a method for decolorizing a polyester, the method including exposing adding a decoloring agent to the polyester and then contacting the polyester with superheated water vapor.
Claims16
A method of decolorizing a polyester, comprising
- adding a degradation agent including an alkali, an acid, a salt thereof, a mono-alcohol, a polyhydric alcohol, or a mixture thereof to the polyester, and
- contacting the polyester with superheated water vapor.
A method of depolymerizing a polyester, comprising
- adding a decoloring agent including an alkali, an acid, a salt thereof, a mono-alcohol, a polyhydric alcohol, or a mixture thereof to polyester, and then contacting the polyester with superheated water vapor to decolorize the polyester,
- depolymerizing the decolorized polyester to obtain a depolymerization product including an alkylene glycol and a dibasic salt,
- performing solid-liquid separation of liquid-phase alkylene glycol and a solid-phase dibasic salt from the depolymerization product,
- dissolving the solid-phase dibasic salt in water,
- neutralizing an aqueous solution of the dibasic salt with an acid to precipitate a dibasic acid crystal, and
- performing solid-liquid separation of the dibasic acid crystal from a precipitation product.
3 more elements
Dependencies are inferred from the claim text.