WO2024256661A1

WO2024256661A1 - Textile recycling

Info

Publication number: WO2024256661A1
Application number: PCT/EP2024/066609
Authority: WO
Inventors: Karzan H. ZANGANA; Antonio Fernandez-Mato; Justin Holmes
Original assignee: University College Cork
Current assignee: University College Cork
Priority date: 2023-06-14
Filing date: 2024-06-14
Publication date: 2024-12-19
Anticipated expiration: 2025-12-14

Abstract

Provided is a method of recycling textile blends, wherein the blend is heated by microwave irradiation to separate the blend components for reuse.

Description

Title of the Invention

Textile Recycling

Field of the Invention

The current invention relates to textile recycling. More specifically, the invention relates to a method of separating components of a textile blend for reuse.

Background of the Invention

Currently, one of the main challenges facing the textile industry is the increasing amount textile waste. More than 50 billion garments are discarded within a year of being made, according to an expert report by Schumacher, K. and Forster, A. (NIST Special Publication 1500-207 (2022). As most of the textiles consumed end up in landfills or are incinerated despite the potential for reuse, there is pressure from all sectors of society towards a reduction in the amount textile waste.

“Fast fashion” has been criticized for its detrimental impact on the environment and excessive resource consumption leading to the generation of a massive amount of textile waste every year. The “fast fashion” business model relies on recurring consumption and impulse buying, which encourages a sense of urgency in purchasing, and the projection is that this industry will continue its outstanding and unsustainable growth. The fashion industry contributes to over 92 million tonne of waste produced per year and in addition to consuming 79 trillion L of water (Niinimaki et al., 2020). According to the UN, the fashion industry is estimated to be responsible for 8 - 10 % of global carbon emissions and only 15 % of textile waste is collected for recycling purposes. To enable implementation of a circular approach within this industry, improvements and advancements in recycling techniques are paramount.

An initiative proposed to alleviate this impact is the proposed EU Waste Framework Directive, that would force to increase the collection and separation of textiles and to be implemented by 1st January 2025 (ref Circular economy perspectives in the EU Textile sector Final report (JRC B.5) June 2021).

For textiles made of pure fibres, mechanical recycling is a viable option. For textile blends, or “mixed textiles”, such as polycotton, chemical recycling is the only solution that allows the recovery of the individual materials currently. Chemical recycling is by depolymerisation using bases or acids or by blend separation by selective dissolution of one of the components.

Chemical recycling has many disadvantages. Both currently used methods of chemical recycling use very toxic solvents, e.g., corrosive acids such as hydrochloric acid or sulfuric acid, that generate toxic and hazardous waste streams and require special disposal. Acids or bases are required for either decoloring and dissolution or depolymerization of at least one component. Common solvents used are ionic liquids, however their impact on the environment and on humans is starting to be questioned (Environ. Sci. Technol. 2019, 53, 18, 10539- 10541 , Int. J. Mol. Sci. 2020, 27(17), 6267, (Holm and Lassi, 2011 ; Hong et al., 2012; Jeihanipour et al., 2010b)) and their level of recyclability is still challenging due to their binary nature (Green Chemical Engineering 2 (2021) 174-186). The methods are also energy intensive (i.e. , heating at a temperature of > 150 °C for several hours) and are not suitable for all combinations of polycotton textiles.

The main drawback of solubilization of one of the components of the blend is the long time required for the recovery of the product. In some cases, hours are required (RSCAdv., 2014,4, 29094-29098, Resources, Conservation & Recycling 145 (2019) 359-369). Another issue comes from the restrictions imposed by the blend ratio during the selective dissolution, as not all the ratios are suitable. In most cases, for each blend ratio, the amount of solvent required needs to be adjusted to the blend ratio which makes some processes highly sensitive, thus limiting their potential towards industrial implementation.

None of the reported processes can handle more than one type of blended mixture. From a material perspective, one of the current major barriers hindering textile recycling is the lack of technologies for separation of different blends before chemical recycling. Current separation technologies are expensive, which discourages the chemical recycling of textiles.

Another limitation of the current practice within the textile recycling field is the colour removal process. Many garments have an array of synthetic dyes which are difficult to degrade (due to the aim of the fashion industry to ensure good ‘colourfastness’ in garments). Two major approaches include dye destruction and dye extraction; however, neither approach is capable of complete removal or providing a sustainable process (Mu and Yang 2022). It is imperative that dyes are removed from textiles correctly and are not released to the environment as they can have severe consequences to human health and aquatic ecosystems (Amalina et al 2022).

WO2014045062 describes a technology that uses thermal heating (by means of electric hotplate, with stirring) prior to separation and cooling, to extract the polyester. Long reaction times are required to separate the materials within the polycotton blend and would be considered an energy intensive process.

US10501599 discuses a subcritical water system used in processing textiles (cotton and or cotton/polyester blend materials). This energy intensive approach uses multiple steps involving high temperatures and high pressure for long periods of time. US11034817 describes a multi-stage process for processing mixed textile feedstock, isolating constituent molecules and regenerating cellulosic and polyester fibers. The process subjected raw material to sequence of one or more pre-treatment steps (including but not limited to, aqueous washing at high temperature and high pressure, supercritical CO2 washing, amorphous phase aqueous treatment, etc.) followed by at least two pulping treatments for isolating molecules.

W2020/252523 describes a multistage process for the separation and recycling of blended polyester and cotton textiles for reuse which includes mixing, blending, acidic catalysis, washing, and filtering.

Sanchis-Sebastia et al (2021) reports a method for acid hydrolysis to directly depolymerise waste textiles into glucose. This process is not intended to be employed for recycling of textiles but rather to make new products (glucose).

Choi & Choi (2019) reported a method for chemical depolymerisation of PET in blend fabrics using microwave-assisted processing and a deep eutectic solvent (Glycerol-Choline Chloride, 5 % NaOH). The end application for fiber identification for quality control and labelling purposes, not for recycling.

Baumi, J, et a;, (Rev. Virtual Quim., 2017, 9(4) 1686-1698) discloses a method of recovering polyamide 66 from textile fabric waste. The method involves heating crude or pure glycerin to 190°C prior to adding a textile fabric and water as a non-solvent to produce recycled polyamide 66 powder. This method allows the recovery of only one component.

There is a need for a more efficient, environmentally friendly, method for chemically recycling textile blends, such as polycotton fabrics.

The current invention solves one or more problems of the prior art and provides an efficient, environmentally friendly, process for chemical recycling of textiles blends.

Summary of the Invention

The current inventors have developed a simplified “green” process for the chemical recycling of textiles. The process allows the recycling of mixtures of blends, e.g., different types of blends together, thus minimizing the need for textile separation. In other words, the process allows for the separation of binary and ternary blends, such as blends of PET, cotton, nylon, elastane samples, that are present in mixtures of unsorted textile blends. These mixtures represent 80-90% of the textile waste generated. Importantly, the process also provides dye removal. The components of the blends are not dissolved in the method of the invention. They detach from their blends. Therefore, recovery time is short, and the recovery yield is high.

It is considered that the solvent acts as a softener and penetrant, breaking the intermolecular interactions between the fibre components of the blend.

An aspect of the invention provides a method of recycling, or separating the components of, at least one textile blend, the method comprising: combining the at least one textile blend and a solvent to provide a reaction mixture, heating the mixture by microwave irradiation to separate at least one component of the at least one textile blend, optionally recovering the separated component(s).

The textile blend comprises two or more fabric components. The method separates the components of the textile blend to provide reusable products.

The textile blend may be a binary blend, a ternary blend or quaternary blend.

In an embodiment, the textile blend comprises (or consists of) synthetic fibre.

In an embodiment, the textile blend comprises (or consists of) non-synthetic fibre.

In an embodiment, the textile blend comprises both synthetic and non-synthetic fibres.

In an embodiment, the synthetic fibers are one or more of polyethylene terephthalate (PET), nylon, elastane, polyurethane, polyvinylchloride and polypropylene. Nylon may be nylon 6 or nylon 66.

In an embodiment, the non-synthetic fibre is a natural fibre or derived from a natural fiber. The natural fibre is one or more of the fibres selected from the group comprising (or consisting of), cotton, linen, viscose, lyocell, wool, flax, leather, and silk. In an embodiment, the non-synthetic fibre may be cotton.

In an embodiment, the textile blend may be a combination of one or more synthetic fibre with one or more non-synthetic fibre in any suitable ratio.

In an embodiment, the textile blend is a combination of two or more of PET, cotton, nylon and elastane, in any suitable ratio or combination.

In an embodiment, the at least one textile blend is a plurality of different textile blends. In other words, it is a mixture of textile blends. Any number of textile blends may be added to the reaction mixture. For example, it may be 2, 3, 4, 5, 6, 8,10, 15 or 20 different textile blends in an unsorted mixture.

The step of heating and optional recovery may be repeated as required until all fibre components in the blends present in the reaction mixture have been separated and optionally recovered. It will be appreciated that the number is dictated by the type of fibre components present and the number of textile blends present in the reaction mixture.

For example, if no mix of textile blends is present and only one type of binary textile blend is added to the reaction mixture the method comprises one heating step and one recovery step.

For example, if two textile blends types are present with two different synthetic fibres in the reaction mixture, for example, PET-cotton and nylon cotton textile blends, the method comprises a first heating step to separate the first synthetic fibre nylon followed by a first recovery step to recover the nylon, and a second heating step by microwave irradiation to separate PET, and a second recovery step.

An exemplary method of an embodiment of the invention comprising two different textile blends as a plurality of textile blends is as follows:

In this embodiment, the method comprises; combining a first textile blend, a second textile blend and a solvent to provide a reaction mixture, heating the mixture by microwave irradiation to separate at least one component of the first textile blend, recovering the separated component from the mixture in a first recovery step, heating the mixture by microwave irradiation to separate at least one component of the second textile blend, recovering the separated component in a second recovery step.

The heating and recovery steps are repeated as necessary until all the fibre components in the blends have been separated and recovered. At the end of this method all the fabric components of the first and second textile blends have been separated and recovered.

If three different textile blends are present in the reaction mixture and a further fibre needs to be separated, the method comprises a third heating step by microwave irradiation after the second recovery step, and so on. It will be appreciated that a third recovery step is also present in the method. In an embodiment, the solvent is selected from glycerol, or a combination of glycerol and one or more polyols, or a combination of glycerol and one or more solvents selected from ethylene carbonate, dimethyl sulfoxide, triacetine, diacetine, -dimethyl carbonate, ethyl lactate, propylene carbonate, gamma-valerolactone, neopentyl glycol, and butyl acetate.

Examples of suitable polyols are selected from polyethylene glycol, polyethylene glycerol and diethylene glycol.

In the combination, the ration of glycerol to polyol or solvent may be 1 :1 to 9.5:0.5, typically, 9:1 or 8:2.

In an embodiment, the solvent consists of glycerol.

In an embodiment, the heating step is at a temperature of from about 100°C to about 200°C, or 150°C, preferably from about 120°C to 130°C.

In an embodiment, the heating step is from 30 seconds to 10 minutes, typically from 1 to 5 minutes, or 1 to 2 minutes.

This may be any heating step of any embodiment of the disclosed aspects of the current invention.

In an embodiment, the at least one textile blend and the solvent are in a ratio of 1 :5 to 1 :15.

The textile blend may comprise more than three fibre components, e.g., it is a ternary blend, the method comprises two heating steps to separate the three components present in the blend. In this regard the method to separate, or recycle, ternary textile blend comprises: combining at least one textile blend comprising three (or more) fibre components, and a solvent to provide a reaction mixture, heating the mixture by microwave irradiation to separate at least first fibre component of the textile blend, recovering the separated first component from the mixture in a first recovery step, heating the mixture by microwave irradiation to separate the second and third components of the textile blend, recovering the separated components in a second recovery step.

If the blend is a quaternary blend, a third heating is required after the second recover step. It will be appreciated that a third recovery step is also present. It is to be understood that the heating and recovery steps are repeated until all fibre components have been separated and recovered.

It will be appreciated that the amount of synthetic fibers present in the blend dictates the number of heating and recovery steps required to separate that blend.

In an embodiment, the method in any embodiment of any aspect of the invention may further comprise recovery of the solvent after the separated components have been recovered. This may be by any suitable means. For example, filtration.

In an embodiment, the at least one textile blend is washed, typically with water, prior to the method, i.e., prior to the step of combining with the solvent. This removes dirt. Optionally, the washed textile blend is then dried. This may be any form of drying, e.g., oven drying.

In an embodiment, the at least one textile blend is cut or divided into pieces of a size sufficient to be placed in the necessary machinery/apparatus used in the method of the invention.

In an embodiment, the reaction mixture is stirred during heating.

The method of the above aspect of the invention also removes, fully or partially, e.g. 70 to 90%, any dye present in the fibers.

An aspect of the invention provides a method to remove dye from at least one textile or at least one textile blend, the method comprising: combining at least one textile or textile blend and a solvent to provide a reaction mixture, heating the mixture by microwave irradiation to remove the dye.

A plurality of textiles or textile blends or a combination thereof may be present in the reaction mixture.

The embodiments discussed in relation to the above first aspect of the invention also apply to this aspect of the invention.

The dye may be direct dyes, basic dyes and/or natural dyes.

A further aspect of the invention provides a product produced by the method(s) of the invention.

In an embodiment of any aspect of the method, the textile blend may be a non-PET blend. In an embodiment of any aspect of the method of the invention, the textile blend is not PET- cotton. Definitions and General Preferences

Where used herein and unless specifically indicated otherwise, the following terms are intended to have the following meanings in addition to any broader (or narrower) meanings the terms might enjoy in the art:

Unless otherwise required by context, the use herein of the singular is to be read to include the plural and vice versa. The term "a" or "an" used in relation to an entity is to be read to refer to one or more of that entity. As such, the terms "a" (or "an"), "one or more," and "at least one" are used interchangeably herein.

As used herein, the term "comprise," or variations thereof such as "comprises" or "comprising," are to be read to indicate the inclusion of any recited integer (e.g., a feature, element, characteristic, property, method/process step or limitation) or group of integers (e.g., features, element, characteristics, properties, method/process steps or limitations) but not the exclusion of any other integer or group of integers. Thus, as used herein the term "comprising" is inclusive or open-ended and does not exclude additional, unrecited integers or method/process steps.

The term “textile” is a fibre, filament or yarn used in making cloth. It may be a natural textile or synthetic. The most common components are fibers. This can be made with one material or a combination of several materials in different ratios, i.e. , a textile blend. It may comprise a dye and/or surface finishes, foam, rubber and coatings, e.g., hydrophobic coatings. Textile fibres can be found in clothing and footwear. The textile blend to be used in the method of the current invention can come from any textile material such as that found in footwear and clothing or similar.

A “toxic solvent” is a liquid substance with a relevant degree of toxicity for humans. Such solvents are known in the art.

The term “textile blend” when used herein is the mixture of two or more fibres. The fibres can be synthetic or non-synthetic. Examples of fibres include but are not limited to cotton, polyester (polyethylene terephthalate (PET)), nylon and elastane. It may be any combination. Examples of blends include but are not limited to cotton-PET, nylon-cotton and nylon-elastane.

“Recycling” is the process of converting materials, such as textiles, into new materials and objects. Ideally the new material is a reusable material.

As used herein the term “depolymerisation” refers to a process of converting a polymer into a monomer or a mixture of monomers. As used herein the term “polyethylene terephthalate (PET), is a thermoplastic resin. It is commonly used in fibres for clothing and containers such as plastic bottles. It is also known as polyester. It consists of polymerised units of the monomer ethylene terephthalate with repeating C10H8O4 units. In this context, PET may be provided as PET or as a plastic product comprising PET. It has the following chemical structure:

As used herein the term “microwave irradiation” is a form of electromagnetic radiation with wavelengths ranging from about 1 metre to one millimetre corresponding to frequencies between 300 MHz and 300 GHz respectively.

As used herein the term “glycerol” is a triol compound (propane-1 , 2, 3, -triol). It is a colourless, viscous liquid and it is the backbone found in lipids known as glycerides. It has the following chemical structure:

Brief Description of the Figures

The current invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying Figures in which;

Figure 1 : Illustrates a flow chart of an embodiment of the method of the invention.

Figure 2: Illustrates powder X ray diffraction spectra of the recovered nylon.

Figure 3: Shows Infra-red spectra for recovered nylon.

Figure 4: Illustrates powder x ray diffraction spectra for recovered elastane.

Figure 5: Shows Infra-red spectra for recovered elastane. Figure 6: Shows Infra-red spectra for recovered cotton.

Figure 7: Illustrates powder X ray diffraction spectra of the recovered cotton.

Figure 8: Shows Infra-red spectra for recovered PET.

Figure 9: Illustrates Powder X ray diffraction spectra of the recovered PET.

Figure 10: (a) Images obtained before and after the chemical separation for the tested

Cotton-Polyester, Cotton-Nylon, Nylon-Elastane, Polyester-Elastane, Viscose-Nylon and Wool-Nylon single blends, (b) to (g) FTIR spectra for the obtained materials in (a) and compared with the respective virgin fabrics.

Figure 11 : PXRD patterns for recovered nylon 6 from cotton-nylon 6, nylon 6-elastane and compared with pure nylon 6 (a-form).

Figure 12: PXRD patterns for recovered nylon 6 (a and y-form) from viscose-nylon 6.

Figure 13: PXRD patterns for viscose recovered from viscose-nylon 6 and compared with virgin viscose.

Figure 14: PXRD patterns for wool recovered from wool-polyester and compared with virgin wool.

Figure 15: PXRD patterns for recovered elastane from polyester-elastane, nylon-elastane and compared with virgin elastane.

Figure 16: TGA curve under N2 for the recovered nylon 6 from cotton-nylon 6, nylon 6- elastane and compared with virgin nylon.

Figure 17: TGA curve under N2 for the recovered viscose from viscose-nylon blend and compared with pure viscose

Figure 18: TGA curve under N2 for the recovered wool from wool-polyester and compared with virgin wool

Figure 19: TGA curve under N2 for the recovered elastane from nylon-elastane, polyester- elastane, and compared with pure elastane.

Figure 20: (a) Images of individual blends before and after the chemical separation, (b)

Images of glycerol recovered during the process for cotton-polyester separation process, both before and after treatment with activated carbon, (c) FTIR spectra illustrating the characteristics of the obtained materials, compared with spectra of the respective virgin fabric. Figure 21 : PXRD patterns for recovered elastane from multifibre (cotton-polyester- elastane) and compared with virgin elastane.

Figure 22: PXRD patterns for recovered polyester from multifibre blend (cotton-polyester- elastane) and compared with virgin polyester.

Figure 23: PXRD patterns for recovered cotton from multifibre blend (cotton-polyester- elastane) and compared with virgin cotton.

Figure 24: FTIR spectra for virgin glycerol, glycerol after use and regenerated glycerol.

Figure 25: Schematic representation of the sequence process employed for the chemical separation and recovery of pure materials from unsorted mixed blends of Nylon-Elastane, Cotton-Polyester, Cotton-Nylon and Polyester-Nylon, using glycerol as solvent.

Figure 26: (a) Images obtained before and after the chemical separation for the tested

Cotton-Polyester, Cotton-Nylon, Nylon-Elastane, Polyester-Elastane mixed blends, (b) to (e) FTIR spectra for the obtained materials, compared with the virgin fabrics.

Figure 27: TGA spectra for virgin cotton and recovered cotton from mixed blends.

Figure 28: TGA spectra for virgin polyester and recovered polyester from mixed blends.

Figure 29: TGA spectra for virgin elastane and recovered elastane from mixed blends.

Figure 30: TGA spectra for virgin nylon and recovered nylon from mixed blends

Figure 31 : PXRD spectra for virgin cotton and recovered cotton from mixed blends.

Figure 32: PXRD spectra for virgin nylon 6 and recovered nylon 6 from mixed blends.

Figure 33: PXRD spectra for virgin elastane and recovered elastane from mixed blends.

Figure 34: PXRD spectra for virgin polyester and recovered polyester from mixed blends.

Detailed description of the Invention

All publications, patents, patent applications and other references mentioned herein are hereby incorporated by reference in their entireties for all purposes as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference and the content thereof recited in full.

The method of the invention combines microwave technology with “green” solvents to convert a material that is considered “waste” after use, into a new resource. The method separates the components of textile blends, which may be binary, ternary or quaternary mixtures, into single components which are reusable.

1 1

SUBSTITUTE SHEET (RULE 26) The aim of the method is to provide attractive and green technology that is as cost-effective as making new fibres from virgin cotton and polyester, thus incentivizing the recycling of textiles instead of using virgin fibers.

In contrast to prior art methods, the method of the invention does not require toxic solvents, is fast, energy efficient, and can be used with any degree of mixture of fibres, e.g., polyester and cotton. Its development aims to expand the implementation of textile recycling, that will be translated into a more sustainable textile industry. In addition, the method of the invention does not require any material solubilization. Therefore, the method is insensitive towards the ratio of the blended mixture and reduces the process time.

Notably, with microwave technology, heating can be achieved in a few minutes and is homogenous throughout the medium. This drastically reduces energy consumption compared to thermal heating and the amount of time required.

In its broadest sense, the method of the invention comprises a heating step wherein at least one textile blend comprising at least two fibre components is heated by microwave energy to separate at least one fibre component. This fibre component is then recovered. The heating step may then be repeated as required until all fibre components have been separated. It will be appreciated that it depends on the number of textile blends, the type of textile blends, e.g. binary/ternary, and the number of synthetic fibre components that require separation,

Different types of textile blends comprise a different blend of fibre components. The textile blend may comprise two or more fibre components. It may be a binary, ternary, quaternary, or quinary blend. Commonly, the textile blend is a binary blend.

Examples, of textile blends are as follows:

In an embodiment, the synthetic fibers are one or more of PET, nylon, elastane, polyurethane, polyvinylchloride and polypropylene. Nylon may be nylon 6 or nylon 66.

In an embodiment, the non-synthetic fibre is a natural fibre or derived from a natural fibre. The natural fibre is one or more of the fibres selected from the group comprising (or consisting of), cotton, linen, viscose, lyocell, wool, flax, leather, and silk. In an embodiment, the non-synthetic fibre may be cotton.

The textile blend may comprise PET in combination with one or more other fibres disclosed herein selected from nylon, elastane, polyurethane, polyvinylchloride, polypropylene, cotton, linen, viscose, lyocell, wool, flax, leather, and silk. For example, it may be PET-nylon, PET- elastane and PET-cotton. The textile blend may be nylon in combination with one or more other fibres disclosed herein selected from PET, elastane, polyurethane, polyvinylchloride, polypropylene, cotton, linen, viscose, lyocell, wool, flax, leather, and silk. For example, it may be nylon-elastane or nylon- cotton.

The textile blend may be elastane in combination with one or more other fibres disclosed herein selected from PET, nylon, polyurethane, polyvinylchloride, polypropylene, cotton, linen, viscose, lyocell, wool, flax, leather, and silk. For example, it may be elastane-cotton.

The textile blend may be cotton in combination with one or more other fibres disclosed herein selected from PET, nylon, polyurethane, polyvinylchloride, polypropylene, elastane, linen, viscose, lyocell, wool, flax, leather, and silk.

The textile blend may be polyurethane in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyvinylchloride, polypropylene, elastane, linen, viscose, lyocell, wool, flax, leather, and silk.

The textile blend may be polyvinylchloride in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polypropylene, elastane, linen, viscose, lyocell, wool, flax, leather, and silk.

The textile blend may be polypropylene in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, linen, viscose, lyocell, wool, flax, leather, and silk.

The textile blend may be linen in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, polypropylene, viscose, lyocell, wool, flax, leather, and silk.

The textile blend may be viscose in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, polypropylene, linen, lyocell, wool, flax, leather, and silk.

The textile blend may be lyocell in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, polypropylene, linen, viscose, wool, flax, leather, and silk.

The textile blend may be wool, in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, polypropylene, linen, viscose, lyocell, flax, leather, and silk. The textile blend may be flax in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, polypropylene, linen, viscose, lyocell, wool, leather, and silk.

The textile blend may be leather in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, polypropylene, linen, viscose, lyocell, wool, flax, and silk.

The textile blend may be silk in combination with one or more other fibres disclosed herein selected from PET, nylon, cotton, polyurethane, polyvinylchloride, elastane, polypropylene, linen, viscose, lyocell, wool, flax, and leather.

Examples of ternary blends are PET-nylon-elastane, PET-nylon-cotton, nylon-elastane-cotton, and PET-cotton-elastane.

Examples of binary blends are cotton-nylon 6, nylon 6-elastane, polyester-elastane, viscose- nylon 6, and wool-polyester.

Any number of textile blends may be added or combined to provide the reaction mixture. For example, it may be 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 8 or more, 10 or more, 15 or more, or 20 or more, different textile blends in an unsorted mixture. In an embodiment, the amount of textile blend types present is from 1 to 3, or 2 to 3.

The temperature of the microwave irradiation, or heating, of any heating step of the method of the invention, is one sufficient to separate the textile blend component(s) desired. The temperature depends on the type of textile blend, e.g. what components are present in the blend. It is preferably, at or below the boiling point of the solvent used, in most cases this is 200°C or below 200°C. The heating step is preferably at a temperature of from about 100°C to 200°C, from about 120°C to 160°C, from about 125°C to 150°C, from about 130°C to 140°C.

The time of this heating step is one sufficient to separate the blend component(s) desired. For example, 30 minutes or less, 25 minutes or less, 20 minutes or less, 15 minutes or less, 12 minutes or less, 10 minutes or less, 10 minutes or less, 9 minutes or less, 8 minutes or less, 7 minutes or less, 6 minutes or less, 5 minutes or less, 4 minutes or less, 3 minutes or less, or 2 minutes or less. Typically, it is from 1 to 30 minutes, from 5 to 25 minutes, from 10 to 15 minutes, from 1 to 5 minutes, from 2 to 4 minutes. The time may be 3 minutes. It will be appreciated that the time depends on the textile blend used.

It will be appreciated that depending on the power of the microwave, the time to reach the targeted temperature will change and therefore, the time of the reaction/heating step may change. The times disclosed herein are for an 800W. Increasing the power of the microwave will reduce the time. The time one sufficient to reach the desired temperature for separation of the desired textile blend.

The temperature of the heating step is dictated by the type of synthetic fibre that is to be separated. Typically, the fibre in the textile blend that requires the lowest temperature setting for separation will be separated first. For example, if nylon is present in the blend and mixed with elastane, elastane will be separated first from nylon as it requires a lower temperature, e.g. 120°C. When the temperature is changed, a different blend/fibre component is separated. In this example, if a plurality of different textile blends is present in the reaction mixture and elastane is part of a second textile blend present, this heating step will separate all elastane present regardless of what fibre it is combined with.

To separate PET from any textile blend the heating step is microwave irradiation at a temperature of about 120°C to 130°C, typically 130°C, is required for typically 2 to 3 minutes or any time sufficient to separate. For example, in an embodiment, the heating step for a polycotton (PET-cotton) blend, i.e. , to separate PET from cotton, is microwave irradiation at a temperature of from 120°C to 130° C, typically about 130°C,

To separate nylon from any textile blend the heating step is microwave irradiation at a temperature of about 120°C to 125°C, typically 125°C, is required for typically 2 to 3 minutes or any time sufficient to separate. For example, in an embodiment, the heating step for cotton- nylon blend, i.e., to separate cotton and nylon, is microwave heating for 2 minutes at a temperature of from about 120°C to about 125 °C, typically about 125°C.

To separate elastane from any textile blend, the heating step is microwave irradiation at a temperature of about 120°C to 125°C, typically 120°C, is required for typically 2 to 3 minutes or any time sufficient to separate. For example, in an embodiment, the heating step for nylon- elastane, e.g., to separate nylon and elastane, is microwave heating for 2 minutes at a temperature of from about 120°C to about 125°C typically, about 120 °C.

To separate one or more of polyurethane, polyvinylchloride, or polypropylene from any textile blend, the heating step is microwave irradiation at a temperature of about 100°C to 150°C, typically 120°C to 135°C, is required for typically 2 to 3 minutes or any time sufficient to separate.

As an example, if the blend is a cotton-polyester-elastane blend, the blend is heated at 120°C (for about 2 minutes) to separate the elastane. The elastane can be removed. The mixture is then heated by microwave heating at 130°C for separation of polyester and cotton fibres.

As a further example, if the textile blends are a plurality of blends being nylon-elastane, nylon- cotton and PET-cotton, the nylon-elastane will be separated first and requires 120°C and nylon and elastane will be recovered. The second step, nylon and cotton will be separated at 125°C and nylon recovered (optionally the cotton). In the 3rd step, PET-cotton will be separated at 130°C and recovered. In an embodiment, the heating step for polycotton blend, is microwave heating at 130°C, typically for 120 seconds. In an embodiment, the solvent used is glycerol. It may be glycerol alone, i.e. , consisting of glycerol, or glycerol may be present in a combination with a polyol or another solvent, preferably non-toxic solvent.

Glycerol is a non-toxic and biodegradable solvent used as an additive in food, drinks, and cosmetics. Glycerol has a very high dielectric constant and high microwave absorption.

The heating step by microwave irradiation separates the components of the blend. The components may then be recovered from the reaction mixture after irradiation. This may be by any suitable means.

To separate the solids from the solvent, filtration using a sieve mesh may be used. To separate solids of different morphology such as particles from fibers, filtration, separation by density or size, or e.g., in a stirred tank with water, and/or centrifugation may be used.

The method may comprise a step of recovering the solvent. The solvent may be reused. Typically, the solvent can be recovered by separation during filtration and reused at least two times without any purification. To reuse the solvent during more cycles, activated carbon may be used, in order to remove colour or other impurities present in the solvent, such as glycerol. Alternatively, the solvent could also be distilled to remove impurities.

The components may be sold or reused for further purposes. For example, the cotton can be used to make new fibers, and these can be used for new textiles, or other applications such as the fabrication of biodegradable products, or for agricultural uses. The PET can be used to make new fibers for new textiles or other applications. It may be used in automotive industry or mixed with virgin PET for packaging or bottles. The nylon can be reused to make new nylon fibers for different applications. Elastane can be used to make new fibers or as coating for water-proof items.

Figure 1 is a simplified representation of the chemical process described for the process of the current invention. This Figure illustrates the sequence of steps for the separation of a mixture of more than one blend. Each step requires a specific temperature (T) and time for the microwave reactor and a specific separation step. As example in the Figure 1 , the first step will be the separation of nylon from nylon-elastane blend and the recovery of nylon. The next step is the separation of nylon from a nylon-cotton blend and recovery of nylon. The last step is the separation of PET and cotton from the PET-cotton mixture and recovery of PET, cotton, and the non-separated cotton from the previous step. In an example embodiment of the invention wherein the reaction mixture comprises two different textile blends, PET-cotton and nylon-cotton, the method comprises: combining PET-cotton and nylon-cotton and a solvent to provide a reaction mixture, heating the reaction mixture by microwave irradiation to separate nylon, recovering the nylon from the reaction mixture, and optionally, the cotton from the nylon-cotton blend, heating the reaction mixture to separate the PET from the cotton, recovering the separated components, i.e. , the PET and the cotton, and optionally the cotton from the first separation step if not yet recovered.

Notably, the method of the invention allows the recovery of the solvent from about 90% to 100%, typically from about 95% to 100%.

Notably, the method of the invention allows the recovery of nylon from about 90% to 100%, preferably, from about 95% to 100%, typically about 95%.

Notably, the method of the invention allows the recovery of cotton from 90% to 100%, preferably, from about 95% to 100%, typically about 98% to 100%.

Notably, the method of the invention allows the recovery of PET from 75% to 100%, typically from about 80% to 95%, or from 85% to 90%.

Notably, the method of the invention allows the recovery of elastane from 90% to 100%, preferably, from about 95% to 100%, typically about 95%.

It is not necessary to add water to the reaction mixture of the current invention as solubilisation is not required for separation.

An aspect of the invention provides a reaction product produced by any one of the methods of the invention. The reaction product is one or more of the separated fibre components. Synthetic fibres will be converted to particles. Non-synthetic or natural fibres will remain as fibres.

It will be appreciated that any embodiment or feature described herein may be combined. In addition, any embodiment or feature described herein may be used in any one of the described aspects of the invention. The invention will now be described with reference to specific Examples. These are merely exemplary and for illustrative purposes only: they are not intended to be limiting in any way to the scope of the monopoly claimed or to the invention described. These examples constitute the best mode currently contemplated for practicing the invention.

EXAMPLES

EXAMPLE 1

Separation of Binary Textile Blends

Methodology

Binary mixtures of polycotton, cotton-nylon or nylon-elastane of post-consumer and postindustrial textile waste samples were prepared by cutting each sample into small squares of around 10cmx10cm. No further pretreatment was used before the process for any of the samples. Figure 1 illustrates the general process followed for the separation of mixtures of more than one blend.

Microwave experiments were performed by initially mixing 1g of the binary mixture of textile with glycerol in ratio 1 :5, in a tubular flask, using different temperatures and reaction times.

The conditions used for this experiment were as follows:

Polycotton blend: microwave for 2 minutes at a temperature of 130° C.

Cottom-Nylon: microwave for 2 minutes at a temperature of 125 °C.

Nylon-elastane: microwave for 2 minutes at a temperature of 120 °C.

During the microwave process, the colour is removed for all the materials.

Immediately, after the microwave process, the detached fibers (PET, nylon, or elastane) were filtered through a sieve meshing, while the cotton fibers, were also separated.

The products obtained after the separation were characterized by Fourier transform infrared spectroscopy (FTIR), powder diffraction X-ray diffraction (PXRD) and scanning electron microscopy (SEM). The characterization was successful and are shown in the Figures 2-9 for each material recovered.

The methods for cotton and nylon IR are as described in Carbohydrate Polymers 123 (2015) 424-431. The methods for elastane are as described in Membranes 2022,12,355 and the methods for PET are as described in Infrared Physics & Technology Volume 101 , September 2019, Pages 119-126. EXAMPLE 2

Separation of Ternary Textile Blends

METHODOLOGY

For ternary mixtures of PET, cotton, nylon or elastane, a two-step process is carried out. For example, a method to separate a blend of PET, cotton and nylon involves a first step to separate cotton-nylon and a second separation of cotton-PET. Figure 1 illustrates the general process followed for the separation of mixtures of more than one blend.

A 1g mixture of any ratio, in this instance 1 :1 :1 , of cotton-nylon and cotton-PET were mixed with glycerol in ratio 1 :5, in a tubular flask. The first separation step to separate the cotton and nylon was carried out. The conditions used were: microwave for 120 seconds at a temperature of 125°C. The products were then recovered. The detached nylon fibers were converted into nylon crystalline particles. Separation was using sieve meshing, where the difference in particle size allows separation of the nylon from the cotton and cotton-PET (polycotton) and separated by filtration through sieve meshing. After the completion of the first step, a second step was performed at 130C for 120 seconds, for the separation of PET from cotton, following the same conditions used for the binary mixtures in the first example. PET is detached from the cotton and the smaller particle size of PET compared to cotton fibers allows the separation by filtration. During the microwave process, the color is removed for all the materials. The products obtained after the separation were characterized by FTIR, PXRD and SEM.

The solvent after use can be regenerated by activated carbon, by removing the colour and small impurities transferred during the microwave process.

EXAMPLE 3

Separation of Textile Blends

The textile blends cotton-nylon 6, nylon 6-elastane, polyester-elastane, viscose-nylon 6, and wool-polyester blends were subjected to the method of the current invention and successfully separated using slightly varied and optimised conditions. The method was also used to separate a blend of cotton-polyester-elastane.

Elastane is particularly problematic, as it is widely used in many textiles at low percentage, and there are currently no published chemical processes capable of recovering pure elastane. During our optimisation process, we determined that each blend requires specific temperature conditions for fibre detachment and separation, and no solubilisation of any material was observed. The reactions proceeded rapidly, in minutes, and the materials were recovered by filtration or decantation, but with optimised temperature conditions. The separation of materials in each blend was facilitated by their differing morphologies, enabling straightforward filtration or decantation.

METHODOLOGY

General process for the preparation of single and mixed blends

All the samples were cut in small squares of 2x2cm and used directly without any pretreatment stage. The products obtained after the separation were characterized by FTIR, PXRD and Thermal analysis.

General process for the separation of single blends and colour removal

Polycotton: A 1g blend of cotton-polyester (55%-45%) from post-consumer waste was mixed with glycerol in ratio a 1 :7(total textiles:glycerol), in a round bottom flask, and the flask was subject to microwave with stirring for 120 seconds at 130 °C. The detached polyester and cotton fibres were separated by filtration with a mesh sieve of 150 microns. The cotton fibres were stirred in water for 30 minutes to remove any remaining polyester that was collected and mixed with the obtained polyester in a yield of > 95% and >98% for cotton.

Cotton-Nylon 6: A 1g blend of cotton-nylon 6 (50%-50%) from post-consumer waste was mixed with glycerol in a ratio 1 :7(total textiles:glycerol), in a round bottom flask, and the flask was subject to microwave with stirring for 120 seconds at 125 °C. The detached nylon 6 particles and cotton fibres were separated by filtration with a mesh sieve of 150 microns. Cotton and nylon 6 samples were washed with water, dried, and collected separately in >98% yield.

Nylon 6-Elastane: A 1g blend of nylon 6-elastane (85%-15%) from post-consumer waste was mixed with glycerol in a ratio 1 :7(total textiles:glycerol), in a round bottom flask, and the flask was subject to microwave with stirring for 120 seconds at 120 °C. The detached elastane was separated by decantation and nylon 6 and elastane samples were washed with water, dried, and collected separately in >98% yield.

Polyester-Elastane: A 1g blend of polyester-elastane (70%-30%) from post-consumer waste was mixed with glycerol in a ratio 1 :7(total textiles:glycerol), in a round bottom flask, and the flask was subject to microwave with stirring for 120 seconds at 120°C. The detached elastane was separated by decantation. Polyester and elastane samples were washed with water, dried, and collected separately in >95% and >98% yield, respectively.

Viscose-Nylon 6: A 1g blend of viscose-nylon 6 (62%-38%) from post-consumer waste was mixed with glycerol in a ratio 1 :7(total textiles:glycerol), in a round bottom flask, and the flask was subject to microwave with stirring for 120 seconds at 125 °C. The detached Nylon 6 and viscose were separated by filtration with a mesh sieve of 150 microns. Viscose and nylon 6 samples were washed with water, dried, and collected separately in >98% yield.

Wool-Polyester: A 1g blend of wool-polyester (50%-50%) from post-consumer waste was mixed with glycerol in a ratio 1 :7(total textiles:glycerol), in a round bottom flask and the flask was subject to microwave with stirring for 120 seconds at 130-140 °C. The detached wool and polyester were separated by filtration with a mesh sieve of 4.75mm. Wool and polyester samples were washed with water, dried, and collected separately in >95% and >98% yield, respectively.

Cotton-Polyester-Elastane: 1g of multifibre blend composed of cotton-polyester-elastane (80%-15%-5%) from post-consumer waste was mixed with glycerol in a ratio 1 :7(total textiles:glycerol), in a round bottom flask and irradiated under microwave for 120 seconds at 120°C. The detached elastane from cotton-polyester was separated by decantation as a foamy material in >98% yield. After the first step, a second step was performed at 130°C for 120 seconds for the separation of polyester as powder from cotton fibres using filtration with a mesh sieve of 4.75mm in >95% and 98% yield, respectively.

Regeneration of glycerol: Recovered glycerol from the final single blend process was mixed with activated carbon and stirred for 30 minutes and subsequently separated by microfiltration using a filter of 0.2pm.

RESULTS

The products obtained were characterised by FTIR, PXRD and TGA, revealing high purity across all five blends, including elastane (Figure 10, and Figures 11-19). In most cases, colour was removed and transferred to the glycerol during microwave processing (Figure 20).

For the nylon 6-elastane and polyester-elastane blends, the temperature was reduced to 120 °C, yielding elastane as a foam, easily separated by decantation. The viscose-nylon 6 blend, separated at 125 °C, PXRD showed viscose fibres as a mixture of cellulose II and IV and nylon 6 as mixture of a and y-form (Figure 11). For the wool-polyester blend, increasing the temperature above 135°C facilitated the separation of wool fibres and polyester particles by filtration.

Given the success with individual blends, the process was tested on a multifibre blend of cotton-polyester-elastane. Two temperatures were required for a sequential fibre detachment. At 120 °C, elastane detached as a foam-like material floating on glycerol, separable from the remaining cotton-polyester fabric by decantation. Increasing the temperature to 130 °C enabled polyester detachment from the cotton fibres, recoverable using the same process as for single blends (Figure 10a, Figure 21 to 23). Across the seven samples tested, most of the colour was removed during fibre detachment and transferred to glycerol. Glycerol’s recyclability was investigated by regeneration, after polycotton separation, with activated carbon and microfiltration (Figure 10 b-c). This process effectively removed colour from glycerol transferring it to activated carbon (Figure 24).

EXAMPLE 4

Separation of textile blends in an unsorted mixture of blends

Given the consistent conditions encountered for all blends and the potential for selective fibre detachment through temperature control, the inventors evaluated the process of the current invention with unsorted mixtures of blends.

METHOD AND RESULTS

The general process for the separation of blends and colour removal was as per the methodology of Example 3 but followed a sequential process. A schematic representation of the process is illustrated in Figure 25.

A blend mixture comprising cotton-polyester, cotton-nylon 6, nylon 6-elastane, and polyester- elastane in a 1:1 :1 :1 ratio was cut into small squares of approximately 2x2 cm (Figure 26a) and combined with glycerol at a ratio of 1 :7 (blend mixture: glycerol). Temperature emerged as the crucial parameter for sequential fibre detachment and blend separation, starting from 120 °C, enabling the separation of nylon 6 from elastane. At this temperature, only elastane from nylon 6-elastane blend was detached and separated via decantation, while the remaining blends remain intact. The detached elastane from nylon 6 was separated as a foamy material by either decantation or mesh sieve, while nylon 6 remained as fibers.

After the first step, a second microwave step was performed at 125°C for 120 seconds for the separation of nylon 6 from cotton. At this temperature all the nylon 6 fibers (from the previous nylon 6-elastane and nylon 6-cotton) were converted into crystalline particles and separated by filtration through mesh sieve from the remaining fibers. This separation method leveraged the difference in size to isolate the nylon 6 from the cotton fibres, while the cotton-polyester blend remained unchanged.

Both, the obtained cotton fibres and the cotton-polyester blend, were subsequently irradiated at 130 °C for three-minutes to detach the polyester from the cotton, employing the same conditions used for the single blends. The polyester fibres, now converted to particles, were detached from the cotton and separated using a sieve mesh obtained from the two blends. Throughout these processes, temperature control ensured that the purity of the resulting samples was maintained during sequential detachment and separation, as confirmed by FTIR, PXRD and SEM analysis (Figure 26, Figure 27 to 34).

Recovered glycerol from the polycotton single blend process was mixed with activated carbon and stirred for 30 minutes and subsequently separated by microfiltration using a filter of 0.2pm.

Equivalents

The foregoing description details presently preferred embodiments of the present invention. Numerous modifications and variations in practice thereof are expected to occur to those skilled in the art upon consideration of these descriptions. Those modifications and variations are intended to be encompassed within the claims appended hereto.

Claims

1 . A method for recycling, or separating, at least one textile blend, the method comprising:

(i) combining at least one textile blend of two or more fibre components and a solvent, to provide a reaction mixture,

(ii) heating the reaction mixture by microwave irradiation at a temperature of from about 100°C to about 150°C for a time sufficient to separate at least one component of at least one textile blend,

(iii) optionally recovering the separated component from the mixture.

2. The method of Claim 1 , wherein the at least one textile blend is a binary blend, a ternary blend, a quaternary blend or a quinary blend.

3. The method of Claim 2, wherein the at least one textile blend is a binary blend.

4. The method of any one of the preceding claims, wherein step (ii) and optionally step (iii) are repeated as required until all fibre components have been separated and optionally recovered.

5. The method of any one of the preceding claims, wherein the at least one textile blend is a plurality of different textile blends.

6. The method of any one of the preceding claims wherein the textile blend comprises (or consists of) synthetic fibers, non-synthetic fibers or a combination of synthetic and nonsynthetic fibers.

7. The method of Claim 6, wherein the non-synthetic fibers are selected from cotton, linen, viscose, wool, flax, lyocell, leather and silk.

8. The method of Claim 6, wherein the synthetic fibers are selected from PET, nylon, elastane, polyvinylchloride, polyurethane and polypropylene.

9. The method of any one of the preceding claims, wherein the one or more textile blend is selected from PET-cotton, PET-nylon, PET-elastane, nylon-cotton, nylon-elastane, and cotton-elastane.

10. The method of any one of the preceding claims, wherein the solvent comprises glycerol.

11 . The method of Claim 10, wherein the solvent is glycerol, a combination of glycerol and one or more polyols optionally selected from polyethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, or a combination of glycerol and one or more solvents selected from ethylene carbonate, triacetine, diacetine, -dimethyl carbonate, ethyl lactate, propylene carbonate, gamma-valerolactone, butyl acetate.

12. The method of any one of the preceding claims, wherein the solvent is glycerol.

13. The method of any one of the preceding claims, wherein the heating temperature is from about 120°C to about 130°C.

14. The method of any one of the preceding claims, wherein the heating step is for about 1 to about 3 minutes.

15. The method of Claim 14, wherein the time is about 2 minutes.

16. The method of any one of the preceding claims wherein the textile blend and the solvent are in a ratio of 1 :5 to 1 :15.

17. The method of any one of the preceding claims, wherein when the at least one textile blend comprises PET, microwave irradiation is at a temperature of about 130° C to remove PET.

18. The method of any one of Claim 1 to 17 wherein when the at least one textile blend comprises nylon microwave irradiation is at a temperature of about 125 °C to remove nylon.

19. The method of any one of Claims 1 to 17, wherein when the at least one textile blend is comprises elastane, microwave irradiation is at a temperature of about 120 °C to remove elastane.

20. The method of any one of the preceding claims, further comprising a step of solvent recovery.

21. The method of any one of the preceding claims, wherein the textile blend is one that formed part of clothing and/or footwear.

22. A method to remove dye from at least one textile or at least one textile blend, the method comprising: combining at least one textile or textile blend and a solvent comprising glycerol to provide a reaction mixture, and heating the mixture by microwave irradiation to remove the dye.

23. A method to recycle, or separate the components of, a textile blend with three or more fibre components, the method comprising:

(i) combining at least one textile blend comprising three or more fibre components, and a solvent to provide a reaction mixture,

(ii) heating the mixture by microwave irradiation to a temperature of from 100°C to 150°C to separate at least a first fibre component of the textile blend,

(iii) optionally recovering the separated first component from the mixture in a first recovery step,

(iv) heating the mixture by microwave irradiation to a temperature of from 100°C to 150°C to separate a second and a third component of the textile blend,

(v) optionally recovering the separated components in a second recovery step.