Method for separating and recycling a waste polyester-cotton textile by means of a hydrothermal reaction catalyzed by an organic acid

Patent metadata

Field	Value
Publication number	US-11396114-B2
Application number	US-201716645453-A
Country	US
Kind code	B2
Filing date	Sep 8, 2017
Priority date	Sep 8, 2017
Publication date	Jul 26, 2022
Grant date	Jul 26, 2022

Abstract

A method for separating and recycling a waste polyester-cotton textile by a hydrothermal reaction catalyzed by an organic acid, comprising the following steps: dividing a waste polyester-cotton textile into fragments and dispersing in an aqueous solution system of the organic acid catalyst to obtain a mixed system; in a high-pressure reactor, heating the mixed system to 110˜180° C. so that cotton fibers in the waste polyester-cotton textile undergo a degradation reaction for 0.5˜3 h to obtain a mixture; and filtering the mixture by a sieve, washing to obtain a polyester fiber aggregate, and then filtering the remaining portion by a filtration membrane in vacuum so as to obtain cotton fiber fragments after washing. Embodiments of the present disclosure may provide advantages for the separation, recycling and reuse of waste polyester-cotton textiles. For example, the catalyst used during processing is derived from nature and is biodegradable.

First claim

What is claimed is:

1. A method comprising:
dividing a waste polyester-cotton textile into fragments and dispersing in an aqueous solution system of an organic acid catalyst to obtain a mixed system;
heating the mixed system to 110˜180° C. in a high-pressure reactor so that cotton fibers in the waste polyester-cotton textile undergo a degradation reaction for 0.5˜3 h to obtain a mixture, wherein the mixed system is heated under stirring at a heating rate of 4° C./min˜6° C./min; and
filtering the mixture by means of a sieve, washing to obtain a polyester fiber aggregate, and then filtering the remaining portion by means of a filtration membrane in vacuum so as to obtain cotton fiber fragments.

2. The method according to claim 1 , wherein the organic acid is methanesulfonic acid, oxalic acid, tartaric acid, citric acid, malic acid, formic acid, or acetic acid.

3. The method according to claim 1 , wherein a content of the polyester in the polyester-cotton textile is 1%˜99% by weight.

4. The method according to claim 1 , wherein a content of the organic acid catalyst in the aqueous solution system is 0.1%˜30% by weight.

5. The method according to claim 1 , wherein a solid-liquid ratio of the mixed system is 1:30˜1:200 by weight.

6. The method according to claim 1 , wherein a spontaneous pressure is formed after heating the mixed system, and the spontaneous pressure is 0.10 MPa˜1 MPa.

7. The method according to claim 1 , further comprising:
washing and drying the polyester fiber aggregate and the cotton fiber fragments respectively in a blast oven to constant weight.

8. The method according to claim 1 , further comprising: converting the polyester fiber aggregate through mechanical action into a fiber raw material for spunning again.

9. The method according to claim 1 , further comprising: recycling the cotton fiber fragments as a raw material for cellulose production.

10. A method comprising:
dividing a waste polyester-cotton textile into fragments;
dispersing the fragments in an aqueous solution system in a presence of an organic acid catalyst to obtain a mixed system;
heating the mixed system in a high-pressure reactor to obtain a mixture, wherein the mixed system is heated under stirring at a heating rate of 4° C./min˜6° C./min; and
filtering the mixture to obtain a polyester fiber aggregate and cotton fiber fragments.

11. The method according to claim 10 , wherein a temperature for heating the mixed system is 110˜180° C.

12. The method according to claim 11 , wherein heating the mixed system is performed such that cotton fibers in the waste polyester undergo a degradation reaction.

13. The method according to claim 11 , wherein heating the mixed system is performed for 0.5˜3 h to obtain the mixture.

14. The method according to claim 10 , wherein filtering the mixture comprises filtering the mixture through a sieve.

15. The method according to claim 14 , further comprising filtering a remaining portion through a filtration membrane in vacuum to obtain the cotton fiber fragments.

16. The method according to claim 10 , further comprising:
washing the polyester fiber aggregate and the cotton fiber fragments; and
drying the polyester fiber aggregate and the cotton fiber fragments respectively in a blast oven to constant weight.

17. The method according to claim 10 , further comprising: converting the polyester fiber aggregate through mechanical action into a fiber raw material.

18. The method according to claim 17 , further comprising spinning the fiber raw material.

19. A method comprising:
dividing a waste polyester-cotton textile into fragments and dispersing in an aqueous solution system of an organic acid catalyst to obtain a mixed system;
heating the mixed system to 110˜80° C. in a high-pressure reactor so that cotton fibers in the waste polyester-cotton textile undergo a degradation reaction for 0.5˜3 h to obtain a mixture;
filtering the mixture by means of a sieve, washing to obtain a polyester fiber aggregate, and then filtering the remaining portion by means of a filtration membrane in vacuum so as to obtain cotton fiber fragments; and
washing and drying the polyester fiber aggregate and the cotton fiber fragments respectively in a blast oven to constant weight.

Assignees

• Hong Kong Res Inst Textiles & Apparel Ltd

Inventors

• Keh Edwin Yee Man
• Yao Lei
• Liao Xiao
• Liu Yang
• Cheuk Kevin
• Chan Alex

Classifications

• C08J11/18

  by treatment with organic material · CPC title

• C08J11/26 Primary

  containing carboxylic acid groups, their anhydrides or esters · CPC title

• C08J2367/02

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

• B29B17/02 Primary

  Separating plastics from other materials · CPC title

• B29B2017/0289

  Washing the materials in liquids · CPC title