Recycling process for the recovery of cotton from polyester-cotton fabrics and/or fibers

Patent metadata

Field	Value
Publication number	US-2023416492-A1
Application number	US-202318244744-A
Country	US
Kind code	A1
Filing date	Sep 11, 2023
Priority date	Dec 2, 2020
Publication date	Dec 28, 2023
Grant date	—

Abstract

Polyester-free cotton is obtained from a fabric and/or fibers containing polyester and cotton by reacting the fabric and/or fibers with an amine organocatalyst and/or carboxylic acid salt of same and an alcohol solvent. The reaction, which may be run in batches or as a continuous flow process, recovers (i) polyester-free cotton as a solid inert by-product of the reaction, (ii) the amine organocatalyst and/or carboxylic acid salt of same for reuse, (iii) a polyester monomer product, and (iv) unreacted alcohol. The reaction works on any polyester-cotton fabric and/or fibers, including those that have at least one additional material, such as polyethers polyolefins, polyurethanes, nylon, rayon, acetate, viscose, modal, acrylic, wool, and combinations thereof.

First claim

We claim:

1 . A method comprising:
placing garneted cotton/polyester fabric in a reaction vessel of a pressure reactor with an amine organocatalyst and/or carboxylic acid salt and an alcohol solvent and heating the reaction vessel to run the reaction; recovering from the reaction vessel (i) polyester-free cotton as a solid inert by-product of the reaction, (ii) the amine organocatalyst and/or carboxylic acid salt of same for reuse, (iii) a polyester monomer product, and (iv) unreacted alcohol solvent; and purifying the recovered polyester-free cotton with a liquid selected from the group consisting of alcohol, acetone, water, and combinations thereof.

2 . The method of claim 1 , wherein the pressure reactor is an autoclave.

3 . The method of claim 1 , wherein the pressure reactor is an extrusion reactor.

4 . The method of claim 1 , wherein the polyester-free cotton is purified with alcohol, wherein the alcohol is the unreacted alcohol solvent recovered from the reaction vessel.

5 . The method of claim 1 , wherein the method is run in batches.

6 . The method of claim 1 , wherein the method is run as a continuous flow process.

7 . The method of claim 1 , wherein the polyester is selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTI), polyethylene furanoate (PEF), and combinations thereof.

8 . The method of claim 1 , wherein the amine organocatalyst and/or carboxylic acid salt of same is selected from the group consisting of triethylamine (TEA), tetramethylethylenediamine (TMEDA), pentamethyldiethylenetriamine (PMDETA), trimethyl triaza cyclononane (TACN), 4-(N,N-dimethylamino)pyridine (DMAP), 1,4-diazabicyclo [2.2.2]octane (DABCO), N-methyl imidazole (NMI), and combinations thereof.

9 . The method of claim 1 , wherein the alcohol solvent is a glycol and/or a diol.

10 . The method of claim 1 , wherein the garneted cotton/polyester fabric is a colored fabric and the recovered polyester-free cotton neutral and/or white reusable cotton.

11 . A method comprising:
placing a garneted cotton/polyester fabric in a reaction vessel of a non-pressurized chemical reactor with an amine organocatalyst and/or carboxylic acid salt and an alcohol solvent and heating the reaction vessel to run the reaction; recovering from the reaction vessel (i) polyester-free cotton as a solid inert by-product of the reaction, (ii) the amine organocatalyst and/or carboxylic acid salt of same for reuse, (iii) a polyester monomer product, and (iv) unreacted alcohol solvent; and purifying the recovered polyester-free cotton with a liquid selected from the group consisting of alcohol, acetone, water, and combinations thereof.

12 . The method of claim 11 , wherein the non-pressurized reactor is a round-bottom flask.

13 . The method of claim 11 , wherein the polyester-free cotton is purified with alcohol, wherein the alcohol is the unreacted alcohol solvent recovered from the reaction vessel.

14 . The method of claim 11 , wherein the method is run in batches.

15 . The method of claim 11 , wherein the method is run as a continuous flow process.

16 . The method of claim 11 , wherein the polyester is selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTI), polyethylene furanoate (PEF), and combinations thereof.

17 . The method of claim 11 , wherein the amine organocatalyst and/or carboxylic acid salt of same is selected from the group consisting of triethylamine (TEA), tetramethylethylenediamine (TMEDA), pentamethyldiethylenetriamine (PMDETA), trimethyl triaza cyclononane (TACN), 4-(N,N-dimethylamino)pyridine (DMAP), 1,4-diazabicyclo [2.2.2]octane (DABCO), N-methyl imidazole (NMI), and combinations thereof.

18 . The method of claim 11 , wherein the alcohol solvent is a glycol and/or a diol.

19 . The method of claim 11 , wherein the garneted cotton/polyester fabric is a colored fabric and the recovered polyester-free cotton neutral and/or white reusable cotton.

Assignees

• IBM

Inventors

• Breyta Gregory
• Allen Robert David

Classifications

• C08J11/28 Primary

  by treatment with organic compounds containing nitrogen, sulfur or phosphorus · CPC title

• C08J11/02

  of solvents, plasticisers or unreacted monomers · CPC title

• D06M13/325

  Amines · CPC title

• D06M13/342

  Amino-carboxylic acids; Betaines; Aminosulfonic acids; Sulfo-betaines · CPC title

• D06M2101/06

  cellulosic · CPC title