# US 2020/0262108 A1 · Method for separating and recycling a waste polyester-cotton textile by means of a hydrothermal reaction catalyzed by an organic acid

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- Number: US 2020/0262108 A1
- Document ID: US20200262108A1
- Status: Published application
- Kind: A1
- Application number: 16/645,453
- Filed: 2017-09-08
- Published: 2020-08-20
- Earliest claimed: 2017-09-08
- Assignees: The Hong Kong Research Institute of Textiles and Apparel Limited
- Applicants: The Hong Kong Research Institute of Textiles and Apparel Limited
- Inventors: Edwin Yee Man KEH; Lei YAO; Xiao LIAO; Yang LIU; Kevin CHEUK; Alex CHAN
- Web page: https://patentgrep.com/patent/US20200262108A1

## CPC

- B29B 17/02: Separating plastics from other materials
- C08J 11/04: of polymers
- C08J 11/26: containing carboxylic acid groups, their anhydrides or esters
- C08L 1/02: Cellulose; Modified cellulose
- B29B 2017/0224: {Screens, sieves}
- B29B 2017/0289: {Washing the materials in liquids}
- B29L 2031/726: {Fabrics (nets B29L2028/00)}
- C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence)
- Y02P 20/143: the feedstock being recycled material, e.g. plastics
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## 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.

## Claims

### Claim 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; 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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

### Claim 6 (depends on 1)

The method according to claim 1, wherein the mixed system is heated under stirring at a heating rate of 4° C./min˜6° C./min.

### Claim 7 (depends on 6)

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

### Claim 8 (depends on 1)

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.

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 1)

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

### Claim 11

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; and
filtering the mixture to obtain a polyester fiber aggregate and cotton fiber fragments.

### Claim 12 (depends on 11)

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

### Claim 13 (depends on 12)

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

### Claim 14 (depends on 12)

The method according to claim 12, wherein heating the mixed system is performed for 0.5˜3 h to obtain the mixture.

### Claim 15 (depends on 11)

The method according to claim 11, wherein filtering the mixture comprises filtering the mixture through a sieve.

### Claim 16 (depends on 15)

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

### Claim 17 (depends on 11)

The method according to claim 11, 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.

### Claim 18 (depends on 11)

The method according to claim 11, further comprising: converting the polyester fiber aggregate through mechanical action into a fiber raw material.

### Claim 19 (depends on 18)

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