Method for decolorization of dyed polyester fiber

Patent metadata

Field	Value
Publication number	US-10876240-B2
Application number	US-201916537483-A
Country	US
Kind code	B2
Filing date	Aug 9, 2019
Priority date	Feb 22, 2019
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A method for decolorization of a dyed polyester fiber is provided. The method for decolorization of a dyed polyester fiber includes step of: providing an ether-alcohol solvent and a polyester fiber containing a dye; heating the ether-alcohol solvent up to a boiling point of the ether-alcohol solvent to continuingly generate a fresh gas; wherein a temperature of the fresh gas ranges from 90° C. to 200° C. which is between a glass transition temperature of the polyester fiber and a melting point of the polyester fiber; extracting the dye from the polyester fiber via the fresh gas and forming an extracting condensate containing the dye; reflowing the extracting condensate back into the ether-alcohol solvent; repeating the steps mentioned above to obtain a decolorized polyester fiber.

First claim

What is claimed is:

1. A method for decolorization of a dyed polyester fiber, consisting of steps of:
(a) providing an ether-alcohol solvent and a polyester fiber containing a dye, and the ether-alcohol solvent consisting of propylene glycol monomethyl ether;
(b) heating the ether-alcohol solvent up to a boiling point of the ether-alcohol solvent to continuingly generate a fresh gas; wherein a temperature of the fresh gas ranges from 90° C. to 200° C. which is between a glass transition temperature of the polyester fiber and a melting point of the polyester fiber;
(c) extracting the dye from the polyester fiber via the fresh gas and forming an extracting condensate containing the dye;
(d) reflowing the extracting condensate back into the ether-alcohol solvent; and
(e) repeating the steps (a) to (d) to obtain a decolorized polyester fiber.

2. The method for decolorization of the dyed polyester fiber according to claim 1 , wherein a color space of the decolorized polyester fiber is defined by L≥80, a≤0, and b≤4 according to JIS Z8729 standard.

3. The method for decolorization of the dyed polyester fiber according to claim 1 , wherein the boiling point of the ether-alcohol solvent ranges from 100° C. to 140° C.

4. The method for decolorization of the dyed polyester fiber according to claim 1 , wherein the dye includes a disperse dye.

5. The method for decolorization of the dyed polyester fiber according to claim 1 , wherein the polyester fiber is separately disposed above the ether-alcohol solvent by a distance so that the fresh gas passes through the polyester fiber and condensates onto the polyester fiber.

Assignees

• Nanya Plastics Corp

Inventors

• Liao Te-Chao
• Chuang Jung-Jen
• Huang zhi-ming
• Huang zhang-jian

Classifications

• C08J2367/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence) · CPC title

• C08J11/06

  without chemical reactions · CPC title

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title

• D06P5/137 Primary

  with other compounds · CPC title

• D06B5/14 Primary

  through fibres, slivers or rovings · CPC title