Separation of elastic fibers in textile materials

Abstract

In a first aspect, the present invention relates to a method for separating a polymer blend comprising (i) a polyamide and / or a cellulosic polymer and (ii) elastic fibers, the method comprising: (a) providing a polymer blend and providing a solvent comprising γ-valerolactone; and (b) contacting the polymer blend with the solvent comprising γ-valerolactone at a temperature T1 of less than 170°C, thereby obtaining a solvent enriched in dissolved elastic fibers and a polymer blend residue depleted of the elastic fibers and comprising the polyamide and / or cellulosic polymer. In a second aspect, the present invention relates to a polyamide and / or cellulosic polymer obtained or obtainable from the method of the first aspect. A third aspect of the present invention relates to the use of the cellulosic polymer of the second aspect, and a fourth aspect of the present invention relates to the use of the polyamide polymer of the second aspect.

Description

[Technical Field]

[0001] In a first aspect, the present invention relates to a method for separating a polymer blend comprising (i) a polyamide and / or a cellulosic polymer and (ii) elastic fibers, the method comprising: (a) providing a polymer blend and providing a solvent comprising γ-valerolactone; and (b) contacting the polymer blend with the solvent comprising γ-valerolactone at a temperature T1 of less than 170°C, thereby obtaining a solvent enriched in dissolved elastic fibers and a polymer blend residue depleted of the elastic fibers and comprising the polyamide or cellulosic polymer. In a second aspect, the present invention relates to a polyamide or cellulosic polymer obtained or obtainable from the method of the first aspect. A third aspect of the present invention relates to the use of the cellulosic polymer of the second aspect, and a fourth aspect of the present invention relates to the use of the polyamide-based polymer of the second aspect. [Background technology]

[0002] The demand for polymer materials has increased dramatically in recent decades. However, their low biodegradability generates large amounts of waste plastic, which in Europe is usually incinerated, resulting in the loss of valuable materials and the emission of huge amounts of CO2. Even more undesirable is the fact that these materials are landfilled. Polymer materials have been widely used in the textile sector, for example, as part of textiles for clothing.

[0003] In particular, blended polymer materials, such as blends of natural polymers such as cotton or synthetic polymers such as polyamides, are often combined with elastic fibers in textile applications to meet customer demands for stretchy garments. However, such blended materials are difficult to recycle at the end of their useful life.

[0004] Techniques for recovering polymeric materials include dissolving the polymeric material. International Publication No. 2016 / 12755 A1 discloses extracting polyester from packaging, using a first solvent to remove colorants and a second solvent to dissolve the polyester. Chen et al. (Wenjun Chen, Yuechao Yang, Xue Lan, Baolong Zhang, Xiaogang Zhang and Tiancheng Mu in Green Chem., 2021, 23, 4065) describes a process for dissolving PET and promoting alkaline hydrolysis. However, these methods have limited applicability, especially when attempting to recover polyester from polymer blends containing each polyester as a single component among multiple other materials.

[0005] Regarding textile materials, WO 2013 / 032408 A1 discloses a method for removing spandex from polyamide elastomer fibers, which includes heat treatment and washing the decomposed spandex using a solvent. WO 2022 / 115602 A1 describes a method for separating blended textile materials or textile mixtures to remove unwanted polymers. However, these methods for separating / removing elastic fibers and / or unwanted polymers always involve the use of hazardous solvents. Summary of the Invention [Means for solving the problem]

[0006] The object underlying the present invention was therefore to provide an improved process which allows for the simple separation of elastic fibers from polymer blends containing polyamide or cellulosic polymers, which also allows for good recovery of the polyamide or cellulosic polymer, and which uses non-hazardous solvents.

[0007] First Aspect - Process - Method for Separating Polymer Blends In a first aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: (i) polyamide and / or cellulosic polymers; (ii) Elastic fiber 1. A method for separating a polymer blend comprising: (a) providing a polymer blend and providing a solvent comprising gamma-valerolactone; (b) contacting a solvent comprising γ-valerolactone with the polymer blend at a temperature T1 of less than 170°C, thereby obtaining a solvent enriched in dissolved elastic fibers and a residue of a polymer blend depleted of the elastic fibers and comprising a polyamide and / or a cellulosic polymer.

[0008] γ-Valerolactone (C5H8O2; IUPAC: 5-methyloxolan-2-one, abbreviation: GVL) can be obtained from carbohydrate-based biomass, for example, easily obtained from sugars, and is therefore a "green" solvent. GVL has previously only been described as being capable of dissolving a single polymer material at most. Surprisingly, it has now been found that the use of a solvent containing GVL in the above-described method for separating a polymer blend containing a polyamide-based polymer and elastic fibers, or a cellulosic polymer and elastic fibers, results in the recovery of the polyamide-based polymer or cellulosic polymer in good yield and purity. It is now possible to effectively remove elastic fibers from the polymer blend without damaging the polyamide-based polymer or cellulosic polymer, thereby opening up a huge field for the reuse of the re-obtained polyamide-based polymer or cellulosic polymer. [Brief explanation of the drawings]

[0009] [Figure 1] 1 shows a comparison of the IR spectra of the material before treatment and the material obtained again after treatment according to Example 1. [Figure 2]1 shows a comparison of the IR spectra of PA obtained again after the separation (treatment) of Example 2 and polyamide 6 (fresh for comparison). [Figure 3] 1 shows a comparison of the IR spectra of the material before treatment in Example 2 and the material (PA) obtained again after treatment. [Figure 4] IR spectra of PA obtained again after separation in Example 3 (processing, IR spectra were taken twice) and polyamide 6.6 (fresh for comparison) are shown. [Figure 5] 1 shows a comparison of the IR spectra of both the re-obtained polyamide and the re-obtained elastic fiber after treatment in Example 3. [Figure 6] 1 shows a comparison of the IR spectra of the re-obtained PA after the treatment of Example 3, the re-obtained elastic fiber, and the GLV. [Figure 7] 1 shows a comparison of the IR spectra of Comparative Examples 1 to 3 and Example 3-PA fraction. DETAILED DESCRIPTION OF THE INVENTION

[0010] "Polymer blend" refers to a combination of at least one polymer with at least one additional component, which is at least another polymer, and these components can be combined with each other in any suitable manner. For example, in the case of at least two polymers, the polymers can be intermixed, or one or more polymers can be embedded in and / or interwoven with one or more other polymers, or the polymers can be arranged in separate layers, as well as hybrid forms of these combinations. For example, a polymer blend is a woven fabric containing elastic fibers and polyamide (PA) or natural polymers such as cotton, viscose, and / or linen, optionally one or more fillers, and optionally one or more additional polymers, such as polyacrylonitrile. Examples of "fillers" include glass fibers, coal fibers, carbon black, inorganic salts (e.g., talc, disodium carbonate), adhesives, thickeners, defoamers, finishing agents (e.g., water-repellent / oil-repellent / stain-resistant agents, flame retardants, wrinkle-resistant agents, biocides), binders, surfactants (e.g., softeners, scouring agents, antistatic agents), desizing agents, bleaching agents, oxidizing agents, UV filters, emulsifiers, fixing agents, cleaning dispersants, and deforming agents. These components are known to those skilled in the art. In some preferred embodiments, the present invention provides a method for producing a cellulose ester-based ... (i) polyamide and / or cellulosic polymers; (ii) Elastic fiber 1. A method for separating a polymer blend comprising: (a) providing a polymer blend and providing a solvent comprising gamma-valerolactone; (b) contacting the polymer blend with a solvent comprising γ-valerolactone at a temperature T1 less than 170° C., thereby obtaining a solvent enriched with dissolved elastic fibers and a residue of a polymer blend depleted of said elastic fibers and comprising a polyamide or cellulosic polymer. In some preferred embodiments, the polymer blend comprises (i) a polyamide or cellulosic polymer, and (ii) elastic fibers. In these embodiments, the invention provides a method for producing a polymer blend comprising: (i) a polyamide or cellulosic polymer; (ii) Elastic fiber 1. A method for separating a polymer blend comprising: (a) providing a polymer blend and providing a solvent comprising gamma-valerolactone; (b) contacting a solvent comprising γ-valerolactone with the polymer blend at a temperature T1 of less than 170°C, thereby obtaining a solvent enriched in dissolved elastic fibers and a residue of a polymer blend depleted of the elastic fibers and comprising a polyamide or a cellulosic polymer.

[0011] In step (b), "contacting" preferably means that the polymer blend is at least partially immersed in the solvent. Preferably, the polymer blend is at least partially immersed in the solvent, and at least 60%, more preferably at least 70%, more preferably at least 80%, more preferably at least 90%, more preferably at least 95%, and more preferably at least 99% of the polymer blend surface is in contact with the solvent, based on 100% of the entire surface of the polymer blend. Generally, there are no specific limitations on the conditions under which the contact in (b) occurs, as long as effective dissolution of the elastic fibers occurs. In step (b), as expected, the elastic fibers are not only dissolved, but also at least partially decomposed.

[0012] In some preferred embodiments of the method for separating a polymer blend, the elastic fibers of (ii) comprise one or more polyurethane-based elastic fibers, and more preferably at least 40% by weight, more preferably at least 45% by weight, more preferably at least 50% by weight, more preferably at least 55% by weight, more preferably at least 60% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight, based on 100% by weight of the total weight of the elastic fibers. "Polyurethane-based elastic fibers" comprise one or more polyurethane-based elastic fibers.

[0013] With respect to the solvent obtained in (b), "concentrated with dissolved elastic fibers" means that the elastic fibers of (ii) have been partially or completely removed from the polymer blend and dissolved in the solvent, and preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 98 wt%, and more preferably at least 99 wt% of the elastic fibers of (ii) have been removed from the polymer blend and dissolved in the solvent, based on 100 wt% of the total weight of the elastic fibers of (ii). With respect to the residue of the polymer blend obtained in (b) containing a polyamide or a cellulose-based polymer, "depleted with said elastic fibers" means that the elastic fibers of (ii) have been partially or completely removed from the polymer blend and dissolved in the solvent. Therefore, the polymer blend residue obtained in (b) preferably contains at most 40% by weight, more preferably at most 30% by weight, more preferably at most 20% by weight, more preferably at most 10% by weight, more preferably at most 5% by weight, more preferably at most 2% by weight, and more preferably at most 1% by weight of the elastic fibers originally contained in the polymer blend, based on 100% by weight, which is the total weight of the elastic fibers originally contained in the polymer blend. In a preferred embodiment in which the elastic fibers (ii) contain one or more polyurethane-based elastic fibers, the percentage values ​​shown above also apply. For example, if at least 90% by weight of the elastic fibers (ii) are polyurethane-based elastic fibers and at least 90% by weight of the elastic fibers (ii) are removed from the polymer blend and dissolved in a solvent, this means that at least 90% by weight of these 90% by weight are removed from the polymer blend.

[0014] In some alternative preferred embodiments of the method for separating a polymer blend, the elastic fibers of (ii) comprise one or more polyester-based elastic fibers, and more preferably at least 40% by weight, more preferably at least 45% by weight, more preferably at least 50% by weight, more preferably at least 55% by weight, more preferably at least 60% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the elastic fibers are polyester-based elastic fibers, each based on 100% by weight of the total weight of the elastic fibers.

[0015] In some alternative preferred embodiments of the method for separating a polymer blend, the elastic fibers of (ii) are a mixture of one or more polyurethane-based elastic fibers and one or more polyester-based elastic fibers, and more preferably at least 40% by weight, more preferably at least 45% by weight, more preferably at least 50% by weight, more preferably at least 55% by weight, more preferably at least 60% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the elastic fibers are a mixture of one or more polyurethane-based elastic fibers and one or more polyester-based elastic fibers, each based on 100% by weight of the total weight of the elastic fibers. In some further alternative preferred embodiments, preferably at least 40% by weight, more preferably at least 45% by weight, more preferably at least 50% by weight, more preferably at least 55% by weight, more preferably at least 60% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the mixture of one or more polyurethane-based elastic fibers, each based on 100% by weight of the total weight of the mixture.

[0016] In these alternative preferred embodiments, the phrase "concentrated dissolved elastic fibers" in relation to the solvent obtained in (b) means that the elastic fibers of (ii), preferably a mixture of one or more polyurethane-based elastic fibers and one or more polyester-based elastic fibers, are partially or completely removed from the polymer blend and dissolved in the solvent, and preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, more preferably at least 98% by weight, and more preferably at least 99% by weight of the mixture of one or more polyurethane-based elastic fibers and one or more polyester-based elastic fibers is removed from the polymer blend and dissolved in the solvent, based on 100% by weight, which is the total weight of the mixture of one or more polyurethane-based elastic fibers and one or more polyester-based elastic fibers contained in the elastic fibers. "The elastic fibers are greatly reduced" in the polymer blend residue obtained in (b) containing polyamide or cellulose polymer means that the elastic fibers (ii), preferably a mixture of one or more polyurethane elastic fibers and one or more polyester elastic fibers, more preferably at least the polyurethane elastic fibers, have been partially or completely removed from the polymer blend and dissolved in a solvent. Thus, the polymer blend residue obtained in (b) contains, compared to the initially provided polymer blend, preferably at most 40% by weight, more preferably at most 30% by weight, more preferably at most 20% by weight, more preferably at most 10% by weight, of the mixture of one or more polyurethane elastic fibers and one or more polyester elastic fibers originally contained in the provided polymer blend, based on 100% by weight, which is the total weight of the mixture of one or more polyurethane elastic fibers and one or more polyester elastic fibers originally contained in the provided polymer blend.

[0017] The polyurethane-based elastic fiber is preferably a polyurethane-based (block) copolymer. The polyurethane-based (block) copolymer is preferably a (block) copolymer of polyurethane and one or more polyethers selected from the group consisting of polyethylene glycol and polytetrahydrofuran, a copolymer of 2-methyl-tetrahydrofuran and tetrahydrofuran, and a copolymer of 3-methyl-tetrahydrofuran and tetrahydrofuran. The polyurethane-based (block) copolymer is more preferably a (block) copolymer of polyurethane and polyethylene glycol or a (block) copolymer of polyurethane and polytetrahydrofuran. More preferably, in each of these polyurethane (block) copolymers, the polyurethane content is at least 85% by weight, based on 100% by weight, which is the total weight of the (block) copolymer. The term "(block) copolymer" refers to both copolymers and block copolymers, with block copolymers being preferred. (Block) copolymers of polyurethane with one or more polyethers selected from the group consisting of polyethylene glycol and polytetrahydrofuran, copolymers of 2-methyl-tetrahydrofuran and tetrahydrofuran, and copolymers of 3-methyl-tetrahydrofuran and tetrahydrofuran, particularly when the polyurethane content is at least 85% by weight based on 100% by weight of the total weight of the (block) copolymer, are also commonly known by the common names "spandex," "elastan(e)," "elastano," "elastam," "elastaan," or "lycra." Trade names include "Lycra," "Elaspan," "Acepora," "Creora," "INVIYA," "ROICA," "Dorlastan," "Linel," and "ESPA." The polyester-based elastic fiber is preferably a poly(trimethylene terephthalate) (PTT) copolymer, more preferably selected from the group of copolyesters synthesized from two or more reactants, each of which has two functional groups capable of forming ester groups.For example, poly(trimethylene terephthalate) copolymers can be produced by copolymerizing 1,3-propanediol with terephthalic acid and, optionally, a linear aliphatic dicarboxylic acid having 4 to 12 carbon atoms, a cycloaliphatic dicarboxylic acid having 4 to 12 carbon atoms, a branched chain aliphatic dicarboxylic acid having 4 to 12 carbon atoms (e.g., butanedioic acid, pentanedioic acid, hexanedioic acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, or their ester-forming equivalents), an aromatic dicarboxylic acid other than terephthalic acid having 8 to 12 carbon atoms (e.g., phthalic acid, isophthalic acid, or 2,6-naphthalenedicarboxylic acid); a linear dicarboxylic acid other than 1,3-propanediol having 2 to 8 carbon atoms, or a cyclic aliphatic dicarboxylic acid having 4 to 12 carbon atoms (e.g., butanedioic acid, pentanedioic acid, hexanedioic acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, or their ester-forming equivalents). Poly(trimethylene terephthalate) copolymers may be prepared by reacting one or more comonomers selected from the group consisting of ether glycols having 4 to 10 carbon atoms, cyclic diols having 2 to 8 carbon atoms, and branched aliphatic diols having 2 to 8 carbon atoms (e.g., ethanediol, 1,2-propanediol, 1,4-butanediol, hexamethylene glycol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propanediol, cyclohexanedimethanol, or 1,4-cyclohexanediol), aliphatic ether glycols having 4 to 10 carbon atoms, and aromatic ether glycols having 4 to 10 carbon atoms (e.g., hydroquinone bis(2-hydroxyethyl) ether). Alternatively, poly(trimethylene terephthalate) copolymers may be prepared from poly(ethylene ether) glycols having a molecular weight of less than 460 g / mol, such as diethylene ether glycol, methoxypolyalkylene glycol, diethylene glycol, and polyethylene glycol. The comonomer is present in the copolymer in the range of 0.5 to 30 mol %, preferably in the range of 0.5 to 20 mol %.The common name for poly(trimethylene terephthalate) (PTT) copolymer is "Sorona," which in some embodiments is a copolymer of 1,3-propanediol (preferably obtained by formation) with terephthalic acid (TPA) or dimethyl terephthalate (DMT), preferably in the range of 20-50 wt. %, more preferably in the range of 30-40 wt. %, of the copolymer is based on 1,3-propanediol obtained from renewable resources, more preferably 1,3-propanediol.

[0018] In some preferred embodiments of the method for separating a polymer blend, the solvent comprising γ-valerolactone is a mixture of γ-valerolactone and, optionally, water and a solvent having a log K in the range of −1.6 to +1.6. OW and preferably water, C5 to C12 alkanes, aliphatic C1 to C10 alcohols, C3 to C10 ketones, C2 to C10 cyclic ketones, HO-[C1 to C10 alkyl-O-] n -H (n is an integer ranging from 2 to 1000), C1 to C10 alkyl-O-C3 to C10 alkyl ether, C3 to C10 cyclic ether optionally substituted with one or more C1 to C6 alkyl groups, C6 to C10 aromatic hydrocarbon optionally substituted with one or more C1 to C6 alkyl groups, C2 to C10 aliphatic ester, C8 to C11 aromatic ester, C5 to C10 cyclic carboxylic acid ester (lactone), C3 to C12 amide, preferably R 1 R 2 NC(=O)-R 3 (In the formula, R 1 , R 2 are independently a C1-C4 alkyl group, and R 3and one or more solvents selected from the group consisting of C1 to C9 alkyl groups, C1 to C10 ester groups and C1 to C6 ether groups, C3 to C6 lactams optionally substituted with one or more substituents selected from C1 to C6 alkyl groups, C1 to C6 ester groups and C1 to C6 ether groups, C5 imidazolidines optionally substituted with one or more C1 to C6 alkyl groups, and C5 to C7 imidazolidines optionally substituted with one or more C1 to C6 alkyl groups.

[0019] In addition to the preferred solvent, the common logarithm of the octanol / water partition coefficient (log K OW ) is also known to those skilled in the art. The octanol / water partition coefficient K of a given compound is OW is defined as the ratio of the chemical concentration of a compound in the octanol phase to the chemical concentration of that compound in the aqueous phase in a two-phase system of 1-octanol and water at a temperature of 25°C (298K). The octanol / water partition coefficient K OW Methods for determining the octanol / water partition coefficient K of a given compound are known to those skilled in the art. OW is determined using the shake-flask method, which consists of dissolving a compound in a predetermined volume of high-purity 1-octanol and deionized water (premixed and conditioned for at least 24 hours) and measuring the compound's concentration in each of the 1-octanol and aqueous phases by a sufficiently accurate method, preferably UV / VIS spectroscopy. This method is described in OECD Guideline for the testing of chemicals No. 107, adopted July 27, 1995. Kow values ​​for several substances are known and can be easily found, for example, in the Dortmund Database (DDB, see http: / / www.ddbst.com / ddb-search).

[0020] Regarding suitable solvents, for example, the aliphatic C1-C10 alcohol is preferably a C1-C6 monool, more preferably one or more selected from the group consisting of methanol, ethanol, and butanol. The C3-C10 ketone is preferably acetone or methyl ethyl ketone, or a mixture of acetone and methyl ethyl ketone. The C2-C10 cyclic ketone is preferably cyclohexanone. The C3-C10 cyclic ether optionally substituted with one or more C1-C3 alkyl groups is preferably tetrahydrofuran or 2-methyltetrahydrofuran, or a mixture of tetrahydrofuran and 2-methyltetrahydrofuran. The C6-C10 aromatic hydrocarbon optionally substituted with one or more C1-C3 alkyl groups is preferably one or more selected from the group consisting of benzene, toluene, ethylbenzene, xylene (o or p), and mesitylene. The C1-C10 ester is preferably one or more selected from the group consisting of esters of C1-C6 aliphatic monools and C2-C5 fatty acids. The C5-C10 cyclic carboxylic acid ester (lactone) is preferably one or more selected from the group consisting of δ-valerolactone, methylated γ-butyrolactone, ethylated γ-butyrolactone, propylated γ-butyrolactone, and β-propiolactone. The C3-C6 lactam optionally substituted with one or more C1-C3 alkyl groups is preferably selected from the group consisting of 2-pyrrolidone, 3-pyrrolidone, and a mixture of 2-pyrrolidone and 3-pyrrolidone, each optionally substituted at the nitrogen atom with one or more C1-C3 alkyl groups, and more preferably N-methyl-2-pyrrolidone. The imidazolidone optionally substituted with one or more C1-C3 alkyl groups is preferably 1,3-dimethyl-2-imidazolidinone.

[0021] In some preferred embodiments of the method for separating a polymer blend, at least 1 wt. % of the solvent consists of γ-valerolactone, more preferably at least 5 wt. %, more preferably at least 10 wt. %, more preferably at least 20 wt. %, more preferably at least 30 wt. %, more preferably at least 40 wt. %, more preferably at least 50 wt. %, more preferably at least 80 wt. %, more preferably at least 90 wt. %, more preferably at least 95 wt. %, more preferably at least 99 wt. %.

[0022] In some preferred embodiments of the method for separating a polymer blend, the polyamide is selected from the group consisting of polyamide 6, polyamide 6.6, and a mixture of polyamide 6 and polyamide 6.6. In some preferred embodiments of the method for separating a polymer blend, the cellulosic polymer is selected from the group consisting of natural cellulosic polymers, synthetic cellulosic polymers, and a mixture of one or more natural cellulosic polymers and one or more synthetic cellulosic polymers, the natural cellulosic polymer is preferably selected from the group consisting of cotton, cellulose, lignin, linen, viscose, and a mixture of two or more thereof, the synthetic cellulosic polymer is preferably viscose, the cellulosic polymer preferably comprises at least cotton, and more preferably at least 65 wt%, more preferably at least 70 wt%, more preferably at least 75 wt%, more preferably at least 80 wt%, more preferably at least 85 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, of the cellulosic polymer is cotton, based on 100 wt%, which is the total weight of the cellulosic polymer, and more preferably the cellulosic polymer is cotton.

[0023] In some preferred embodiments of the method for separating a polymer blend, the contacting in (b) is carried out at a weight-based ratio of the polymer blend provided in (a) to the solvent in the range of 1:1 to 1:100, preferably in the range of 1:1 to 1:50, and more preferably in the range of 1:1 to 1:10.

[0024] In some preferred embodiments of the method for separating a polymer blend, the contacting in (b) is carried out for a period of at least 5 minutes, preferably in the range of 5 minutes to 10 hours, more preferably in the range of 5 minutes to 6 hours, and more preferably in the range of 5 minutes to 4 hours.

[0025] In some preferred embodiments of the method for separating a polymer blend, T1 is a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 110 to 165°C, more preferably a temperature in the range of 120 to 150°C.

[0026] In some preferred embodiments of the method for separating a polymer blend, when the elastic fiber (ii) comprises one or more polyurethane-based elastic fibers, T1 is a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 110 to 165°C, and more preferably a temperature in the range of 120 to 150°C.

[0027] In some preferred embodiments of the method for separating a polymer blend, when the elastic fiber (ii) comprises one or more polyester-based elastic fibers, T1 is a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 130 to 165°C, and more preferably a temperature in the range of 140 to 165°C.

[0028] In some preferred embodiments of the method for separating a polymer blend, the method comprises: (c) Separating the solvent enriched in dissolved elastic fibers obtained in (b) from the polymer blend residue, preferably by a physical separation method, thereby obtaining a separated solvent enriched in dissolved elastic fibers compared to the solvent provided in (a), and a polymer blend residue depleted in the elastic fibers and comprising polyamide or cellulosic polymer.

[0029] In some preferred embodiments of the method for separating a polymer blend, the method comprises: (d) optionally washing the elastic fiber-depleted residue of the polymer blend comprising polyamide and / or cellulosic polymer obtained in (c), thereby obtaining a washed residue of the polymer blend comprising polyamide and / or cellulosic polymer; (e) drying the polymer blend residue obtained in (c) or the washed polymer blend residue obtained in (d), thereby obtaining a dried polymer blend residue comprising a polyamide and / or a cellulosic polymer.

[0030] In some preferred embodiments of the method for separating a polymer blend, for washing in step (d), a solvent selected from the group consisting of γ-valerolactone, methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water or a mixture of two or more of these solvents is used, preferably a solvent comprising at least acetone, more preferably acetone.

[0031] In some preferred embodiments of the method for separating a polymer blend, method (d) comprises: (d.1) optionally washing the polymer blend residue obtained in(c) with a wash solution comprising a solvent comprising gamma-valerolactone and removing the wash solution to obtain a pre-washed polymer blend residue; (d.2) optionally washing the pre-washed residue of the polymer blend obtained in (d.1) with a solvent selected from the group consisting of γ-valerolactone, methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water or a mixture of two or more of these solvents, preferably a solvent comprising at least acetone, more preferably acetone, is used, thereby obtaining a washed residue of a polymer blend comprising a polyamide and / or a cellulosic polymer.

[0032] In some preferred embodiments of the method for separating a polymer blend, drying in step (e) of the polymer blend obtained in (c) or the washed residue of the polymer blend obtained in (d) is carried out under one or more conditions selected from the group consisting of a pressure in the range of 1 to 1013 mbar; a temperature in the range of 50 to 210°C, preferably in the range of 60 to 180°C, more preferably in the range of 80 to 150°C; a drying time in the range of 30 minutes to 24 hours; and drying in an atmosphere comprising nitrogen, preferably in an atmosphere where nitrogen is at least 90% by volume, more preferably 95% by volume, more preferably at least 98% by volume.

[0033] In some preferred embodiments of the process for separating a polymer blend, drying in step (e) of the polymer blend obtained in (c) or the washed residue of the polymer blend obtained in (d) is carried out by one or more methods selected from the group consisting of contact drying, convective drying, and radiative drying.

[0034] In some preferred embodiments of the process for separating polymer blends, the process comprises at least partially recycling the separated solvent obtained in (c) to (b), optionally after one or more post-treatment steps.

[0035] In some preferred embodiments of the method for separating a polymer blend, at least one of steps (a), (b), (c), optionally (d), optionally (d.1), optionally (d.2) and (e), preferably all of these steps, is carried out at a pressure in the range of 800 to 200,000 hPa.

[0036] In embodiments in which polyamide and cellulosic polymer are present in the remainder of the polymer blend, they can optionally be separated by depolymerizing the polyamide and then removing the monomers from the remaining non-depolymerized cellulosic polymer, or by dissolving the polyamide using a suitable solvent that does not dissolve the cellulosic polymer, or by dissolving the cellulosic polymer in a suitable solvent that does not dissolve the polyamide.

[0037] In some preferred embodiments of the method for separating a polymer blend, when the polymer blend residue comprises a cellulosic polymer, the method further comprises: separating the cellulosic polymer obtained in (d), (d.2) or (e) by: - mechanical treatment, preferably selected from the group consisting of crushing, stirring, shredding, tearing and combinations of two or more of these treatments; - a thermal treatment, preferably selected from the group consisting of freezing, heating or boiling, and combinations of two or more of these treatments, preferably in combination with the application of excess pressure (excess pressure = pressure above 1013 mbar); - incubation in an aqueous alkaline medium, preferably comprising water and one or more alkaline salts, preferably sodium salts selected from the group consisting of sodium hydroxide, sodium carbonate, sodium monochloroacetate and mixtures of two or more thereof; - incubation in an acidic medium, preferably in one or more acids selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid and formic acid; - incubation in an ionic liquid, preferably in one or more ionic liquids selected from the group consisting of 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]) and 1,5-diazabicyclonon-5-enium acetate ([DBNH][OAc]); - incubation in N-methylmorpholine-N-oxide (NMMO); - ultrasonic treatment; - Radiation; - addition of an enzyme preferably selected from the group consisting of cellulase, protease, pectinase, glucosidase, glucanotransferase, PET hydrolase (PETase) and lipase, and mixtures of two or more of these enzymes, more preferably selected from the group consisting of β-1,4-exoglucanase, β-1,4-endoglucanase, β-1,4-cellobiohydrolase, β-glucosidase, pyrrolase, and mixtures of two or more of these enzymes; and - microbial cultivation, preferably by adding cellulolytic bacterial or fungal strains or mixed cultures; and further post-processing by applying one or more treatments selected from the group consisting of:

[0038] Each of the above-listed incubation treatments in the solvents optionally uses one or more cosolutes, preferably urea and / or polyethylene glycol (PEG). The treatments as indicated above result in: a reduction in crystallinity, preferably cellulose crystallinity, and an increase in amorphous structure; a reduction in polymerization, preferably polymerization; fiber swelling; polarity of cellulose macromolecules; preferably cellulose I (cellulose I). α ) to cellulose II (cellulose I β ), fiber orientation inducing a transition to intramolecular and intramolecular hydrogen bonding, electrostatic bonding and van der Waals forces; available surface area, preferably an increase in the available surface area; and moisture content.

[0039] In some preferred embodiments of the method for separating a polymer blend, the method further comprises, when the residue of the polymer blend comprises a polyamide, post-treating the polyamide obtained in (d), (d.2) or (e) by a method selected from the group consisting of depolymerizing the polyamide into its oligomeric and / or monomeric fragments, mechanical recycling such as extrusion, re-granulation, compounding, and a combination of two or more of these methods.

[0040] Second embodiment - polyamide and / or cellulosic polymer In a second aspect, the present invention relates to a polyamide-based polymer and / or a cellulosic polymer obtained or obtainable from the method of the first aspect, and all details and preferred embodiments described in relation to the first aspect also apply to the second aspect.

[0041] Third mode - Use of cellulosic polymers A third aspect of the present invention is - as a combustible material in heating and power plants; - as a feedstock in anaerobic digestion plants, preferably biogas reactors; - As a substrate for wastewater treatment plants; - As input material for bio-refineries, preferably biofuel plants; - as input material in gasification plants, preferably for producing synthesis gas or hydrogen; - as input material in pyrolysis reactions or pyrolysis plants; - as an input material in the superheated steam carbonization (HTC) process; and / or - Use of the cellulosic polymer of the second aspect as a feedstock in a bacterial or fungal fermentation process.

[0042] Fourth embodiment: Use of polyamide polymers A fourth aspect of the invention relates to the use of a polyamide polymer of the second aspect for preparing a textile, an automotive fiber, an industrial fiber, or an engineering plastic.

[0043] The present invention is further illustrated by the following series of embodiments and combinations of embodiments, which can be obtained from the indicated dependencies and backward references. In particular, it is pointed out that in each case where a range of embodiments is mentioned, for example in connection with a term such as "the method according to any one of embodiments 1 to 4," it means that all embodiments within this range are expressly disclosed to those skilled in the art, that is, the use of this term should be understood by those skilled in the art to be synonymous with "the method according to any one of embodiments 1, 2, 3, and 4." Furthermore, it is explicitly pointed out that the following series of embodiments represent a properly structured part of the general description of preferred aspects of the present invention, and therefore properly support the claims of the present invention, but do not represent the scope of the claims of the present invention.

[0044] 1. (i) polyamide and / or cellulosic polymers; (ii) Elastic fiber 1. A method for separating a polymer blend comprising: (a) providing a polymer blend and providing a solvent comprising gamma-valerolactone; (b) contacting a solvent comprising γ-valerolactone with the polymer blend at a temperature T1 of less than 170°C, thereby obtaining a solvent enriched in dissolved elastic fibers and a residue of a polymer blend depleted of the elastic fibers and comprising a polyamide and / or a cellulosic polymer.

[0045] 2. A method for separating a polymer blend according to embodiment 1, wherein the elastic fibers (ii) are one or more polyurethane-based elastic fibers, and more preferably at least 40% by weight, more preferably at least 45% by weight, more preferably at least 50% by weight, more preferably at least 55% by weight, more preferably at least 60% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the elastic fibers are polyurethane-based elastic fibers, each based on 100% by weight of the total weight of the elastic fibers.

[0046] 3. A method for separating a polymer blend according to embodiment 1, wherein the elastic fibers (ii) comprise one or more polyester-based elastic fibers, and preferably at least 40% by weight, more preferably at least 45% by weight, more preferably at least 50% by weight, more preferably at least 55% by weight, more preferably at least 60% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the elastic fibers are polyester-based elastic fibers, each based on 100% by weight of the total weight of the elastic fibers.

[0047] 4. A method for separating a polymer blend according to any one of embodiments 1 to 3, wherein the elastic fibers (ii) are a mixture of one or more polyurethane-based elastic fibers and one or more polyester-based elastic fibers, and preferably at least 40% by weight, more preferably at least 45% by weight, more preferably at least 50% by weight, more preferably at least 55% by weight, more preferably at least 60% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the elastic fibers are a mixture of one or more polyurethane-based elastic fibers and one or more polyester-based elastic fibers, each based on 100% by weight of the total weight of the elastic fibers.

[0048] 5. A method for separating a polymer blend according to any one of embodiments 1 to 4, wherein the solvent comprising γ-valerolactone is a mixture of γ-valerolactone and, optionally, water and a solvent having a log K in the range of −1.6 to +1.6. OW and preferably water, C5 to C12 alkanes, aliphatic C1 to C10 alcohols, C3 to C10 ketones, C2 to C10 cyclic ketones, HO-[C1 to C10 alkyl-O-] n -H (n is an integer ranging from 2 to 1000), C1 to C10 alkyl-O-C3 to C10 alkyl ether, C3 to C10 cyclic ether optionally substituted with one or more C1 to C6 alkyl groups, C6 to C10 aromatic hydrocarbon optionally substituted with one or more C1 to C6 alkyl groups, C2 to C10 aliphatic ester, C8 to C11 aromatic ester, C5 to C10 cyclic carboxylic acid ester (lactone), C3 to C12 amide, preferably R 1 R 2 NC(=O)-R 3 (In the formula, R 1 , R 2 are independently a C1-C4 alkyl group, and R 3is selected from the group consisting of a C1 to C9 alkyl group, a C1 to C10 ester group and a C1 to C6 ether group, a C3 to C6 lactam optionally substituted with one or more substituents selected from a C1 to C6 alkyl group, a C1 to C6 ester group and a C1 to C6 ether group, a C5 imidazolidine optionally substituted with one or more C1 to C6 alkyl groups, and a C5 to C7 imidazolidine optionally substituted with one or more C1 to C6 alkyl groups.

[0049] 6. A method for separating a polymer blend according to any one of embodiments 1 to 5, wherein the polyamide is selected from the group consisting of polyamide 6, polyamide 6.6, and a mixture of polyamide 6 and polyamide 6.6.

[0050] 7. A method for separating a polymer blend according to any one of embodiments 1 to 6, wherein the cellulosic polymer is selected from the group consisting of natural cellulosic polymers, synthetic cellulosic polymers, and mixtures of one or more natural cellulosic polymers with one or more synthetic cellulosic polymers; the natural cellulosic polymer is preferably selected from the group consisting of cotton, cellulose, lignin, linen, viscose, and mixtures of two or more thereof; the synthetic cellulosic polymer is preferably viscose; the cellulosic polymer preferably comprises at least cotton; and more preferably at least 65 wt%, more preferably at least 70 wt%, more preferably at least 75 wt%, more preferably at least 80 wt%, more preferably at least 85 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, of the cellulosic polymer is cotton, based on 100 wt%, which is the total weight of the cellulosic polymer; and more preferably the cellulosic polymer is cotton.

[0051] 8. The method for separating a polymer blend according to any one of embodiments 1 to 7, wherein the contacting in (b) is carried out at a weight ratio of the polymer blend provided in (a) to the solvent in the range of 1:1 to 1:100, preferably in the range of 1:1 to 1:50, more preferably in the range of 1:1 to 1:10, based on weight.

[0052] 9. A method for separating a polymer blend according to any one of embodiments 1 to 8, wherein the contacting in (b) is carried out for a period of at least 5 minutes, preferably in the range of 5 minutes to 10 hours, more preferably in the range of 5 minutes to 6 hours, more preferably in the range of 5 minutes to 4 hours.

[0053] 10. A method for separating a polymer blend according to any one of embodiments 1 to 9, wherein T1 is a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 110 to 165°C, more preferably a temperature in the range of 120 to 150°C.

[0054] 11. The method for separating a polymer blend according to embodiment 10, wherein when the elastic fibers (ii) comprise one or more polyurethane-based elastic fibers, T1 is a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 110 to 165°C, more preferably a temperature in the range of 120 to 150°C.

[0055] 12. The method for separating a polymer blend according to embodiment 10, wherein when the elastic fibers (ii) comprise one or more polyester-based elastic fibers, T1 is a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 130 to 165°C, more preferably a temperature in the range of 140 to 165°C.

[0056] 13. A method for separating a polymer blend according to any one of embodiments 1 to 12, comprising: (c) separating the solvent enriched in dissolved elastic fibers obtained in (b) from the polymer blend residue, preferably by a physical separation method, thereby obtaining a separated solvent enriched in dissolved elastic fibers compared to the solvent provided in (a) and a polymer blend residue depleted in the elastic fibers and comprising polyamide and / or cellulosic polymer.

[0057] 14. A method for separating a polymer blend according to any one of embodiments 1 to 13, comprising: (d) optionally washing the elastic fiber-depleted residue of the polymer blend comprising polyamide and / or cellulosic polymer obtained in (c), thereby obtaining a washed residue of the polymer blend comprising polyamide and / or cellulosic polymer; (e) drying the polymer blend residue obtained in (c) or the washed polymer blend residue obtained in (d), thereby obtaining a dried polymer blend residue comprising a polyamide and / or a cellulosic polymer.

[0058] 15. A process for separating a polymer blend according to embodiment 14, wherein for washing in step (d) a solvent selected from the group consisting of γ-valerolactone, methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water or a mixture of two or more of these solvents is used, preferably a solvent comprising at least acetone, more preferably acetone.

[0059] 16. A method for separating a polymer blend according to embodiment 14 or 15, wherein step (d) comprises: (d.1) optionally washing the polymer blend residue obtained in(c) with a wash solution comprising a solvent comprising gamma-valerolactone and removing the wash solution to obtain a pre-washed polymer blend residue; (d.2) optionally washing the pre-washed residue of the polymer blend obtained in (d.1) with a solvent selected from the group consisting of γ-valerolactone, methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water or a mixture of two or more of these solvents, preferably a solvent comprising at least acetone, more preferably acetone, is used, thereby obtaining a washed residue of a polymer blend comprising a polyamide and / or a cellulosic polymer.

[0060] 17. A process for separating a polymer blend according to any one of embodiments 14 to 16, wherein the drying in step (e) of the polymer blend obtained in (c) or the washed residue of the polymer blend obtained in (d) is carried out under one or more conditions selected from the group consisting of a pressure in the range of 1 to 1013 mbar; a temperature in the range of 50 to 210°C, preferably in the range of 60 to 180°C, more preferably in the range of 80 to 150°C; a drying time in the range of 30 minutes to 24 hours; and drying in an atmosphere comprising nitrogen, preferably in an atmosphere where nitrogen is at least 90% by volume, more preferably 95% by volume, more preferably at least 98% by volume.

[0061] 18. The process for separating a polymer blend according to any one of embodiments 14 to 17, wherein the drying in step (e) of the polymer blend obtained in (c) or the washed residue of the polymer blend obtained in (d) is carried out by one or more methods selected from the group consisting of contact drying, convective drying and radiation drying.

[0062] 19. A process for separating a polymer blend according to any one of embodiments 1 to 18, comprising at least partially recycling the separated solvent obtained in (c) to (b), optionally after one or more post-treatment steps.

[0063] 20. A process for separating a polymer blend according to any one of embodiments 1 to 19, wherein at least one of steps (a), (b), (c), optionally (d), optionally (d.1), optionally (d.2) and (e), preferably all of these steps, are carried out at a pressure in the range of 800 to 200,000 hPa.

[0064] 21. The method for separating a polymer blend according to any one of embodiments 1 to 20, wherein the polymer blend residue comprises a cellulosic polymer, the cellulosic polymer obtained in (d), (d.2) or (e) being: - mechanical treatment, preferably selected from the group consisting of crushing, stirring, shredding, tearing and combinations of two or more of these treatments; - a thermal treatment, preferably selected from the group consisting of freezing, heating or boiling, and combinations of two or more of these treatments, preferably in combination with the application of excess pressure (excess pressure = pressure above 1013 mbar); - incubation in an aqueous alkaline medium, preferably comprising water and one or more alkaline salts, preferably sodium salts selected from the group consisting of sodium hydroxide, sodium carbonate, sodium monochloroacetate and mixtures of two or more thereof; - incubation in an acidic medium, preferably in one or more acids selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid and formic acid; - incubation in an ionic liquid, preferably in one or more ionic liquids selected from the group consisting of 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]) and 1,5-diazabicyclonon-5-enium acetate ([DBNH][OAc]); - incubation in N-methylmorpholine-N-oxide (NMMO); - ultrasonic treatment; - Radiation; - addition of an enzyme preferably selected from the group consisting of cellulase, protease, pectinase, glucosidase, glucanotransferase, PET hydrolase (PETase) and lipase, and mixtures of two or more of these enzymes, more preferably selected from the group consisting of β-1,4-exoglucanase, β-1,4-endoglucanase, β-1,4-cellobiohydrolase, β-glucosidase, pyrrolase, and mixtures of two or more of these enzymes; - microbial cultivation, preferably by adding cellulolytic bacterial or fungal strains or mixed cultures; The method further comprising post-processing by applying one or more treatments selected from the group consisting of:

[0065] 22. The method for separating a polymer blend according to any one of embodiments 1 to 20, wherein when the polymer blend residue comprises a polyamide, the method further comprises post-treating the polyamide obtained in (d), (d.2) or (e) by a method selected from the group consisting of depolymerizing the polyamide into its oligomeric and / or monomeric fragments, mechanical recycling such as extrusion, re-granulation, compounding, and a combination of two or more of these methods.

[0066] 23. A polyamide and / or cellulosic polymer obtained or obtainable by the method according to any one of embodiments 1 to 22.

[0067] twenty four. - as a combustible material in heating and power plants; - as a feedstock in anaerobic digestion plants, preferably biogas reactors; - As a substrate for wastewater treatment plants; - As input material for bio-refineries, preferably biofuel plants; - as input material in gasification plants, preferably for producing synthesis gas or hydrogen; - as an input material in a pyrolysis reaction or in a pyrolysis reaction plant; and / or - As an input material in the superheated steam carbonization (HTC) process; - Use of the cellulosic polymer of embodiment 23 as a feedstock in a bacterial or fungal fermentation process.

[0068] 25. Use of the polyamide polymer according to embodiment 23 for preparing textiles, automotive applications, technical fibers, or engineering plastics.

[0069] The present invention is further illustrated by the following Reference Examples, Comparative Examples and Examples. [Example]

[0070] method quantitative 1 H NMR spectroscopy (q 1 H NMR): Quantitative determination of polyamide (PA) and gamma-valerolactone (GVL) content in samples 1 All NMR spectra were measured by H-NMR spectroscopy. 1 Recordings were made on a Bruker Avance III 400 spectrometer operating at 400.33 MHz for H at T = 298.2 K. The spectrometer was fitted with a 5 mm z-gradient broadband observe smartprobe. 1 H 1D spectra were recorded under quantitative conditions using the zg30 pulse program with 128k data points. The relaxation delay D1 was selected as 45 seconds for hexafluoro-2-propanol (HFIP) and 120 seconds for sulfuric acid-d2 (D2SO4). Eight transients were used per spectrum. Processing was performed using Bruker TopSpin 4.1.4 software with 128k data points, 0.3 Hz line broadening, and an exponential window function. Automatic baseline correction was performed with a polynomial order of 3, and phase correction and integration were performed manually by the user.

[0071] To measure PA and GVL from fibers, samples were prepared by accurately weighing the internal standard 1,2,4,5-tetrachloro-3-nitrobenzene (Tecna) and analyte into suitable vials (Mettler-Toledo XP205DR analytical balance) and then dissolving in 2 mL of HFIP. Chemical shifts were referenced to hexafluoro-2-propanol-d2 (HFIP, δ(HFIP) = 4.25 ppm).

[0072] To measure PA and GVL from elastic fibers, samples were prepared by accurately weighing (Mettler-Toledo XP205DR analytical balance) the internal standard dimethylmalonic acid (DMMS) and the analyte into suitable vials, followed by dissolution in 2 ml of D2SO4.

[0073] In all cases, samples were transferred to 5 mm NMR tubes for measurement. The deuterated solvent HFIP was purchased from Euriso-Top GmbH. D2SO4, Tecna, and DMMS (certified internal standard) were purchased from Sigma-Aldrich. All solvents and internal standards were used as received.

[0074] The content of the test article was calculated using the following formula:

number

[0075] For quantification, measurements were performed in triplicate.

[0076] The PA was assessed using an internal standard of 1 proton / molecule (approximately 7.6 ppm) of Tecna and 2 selected protons / molecule (approximately 2.2 ppm) of the analyte PA.

[0077] The GVL was evaluated using an internal standard of DMMS with 6 protons / molecule (approximately 1.80 ppm) and an analyte of GVL with 3 protons / molecule (approximately 1.7 ppm).

[0078] Infrared spectroscopy (IR): FTIR-ATR spectra were obtained by FTIR spectrometers equipped with ATR units (Thermo Nicolet 6700+diamond ATR unit (PIKE GladiATR) and Thermo iS10+ZnSe ATR unit (Smart Performer)).

[0079] For the measurements, the sample was placed directly on the ATR crystal without further preparation and fixed with the stamp of the unit. All measurements were performed with 32 scans and a 4 cm -1 The analysis was carried out at room temperature (25°C) using a resolution of 100 kHz.

[0080] [Table 1]

[0081] Reference Example 1: General procedure for separating elastic fibers from cotton or PA The polymeric material (any color) was cut / shredded into small pieces and placed in a reaction vessel (e.g., flask, tube, or reactor). Degassed GVL was added (at a polymeric material:GVL mass ratio of 1:1 to 1:100, preferably 1:1 to 1:10), and the mixture was heated to 110 to 170 °C using a suitable heating system (e.g., oil bath, heating block, or mini-plant). After 0.1 to 6 hours, the mixture was filtered to obtain GVL enriched with elastic fibers and cellulose-based or PA fragments. The polymeric material fragments were washed with a small amount of GVL. To facilitate the removal of the GVL and expedite the drying process of the cellulose-based or PA fragments free of elastic fibers, a small amount of acetone may be used in a second washing step. The resulting polymeric material fragments were then dried (e.g., in a vacuum tray dryer).

[0082] Analyze the samples before treatment (colored polymer material, Tables 1-4) and after the final drying step (polymer material with significantly reduced elastic fiber content, Tables 1-4). When separating PA / elastic fiber, quantitative analysis is performed. 1 H-NMR was measured to determine the PA content, and IR spectroscopy showed that the characteristic peaks before and after treatment changed compared to known spectra for polyamide 6, polyamide 6.6, and polyurethane- and polyether-based elastic fibers. In the case of cellulosic polymer / elastic fibers, IR spectroscopy demonstrated separation and showed that the characteristic peaks before and after treatment changed compared to known spectra for cotton, and polyurethane- and polyether-based elastic fibers.

[0083] For all procedures the following applied: To recycle the spent solvent GVL, the filtrate was distilled (50-200°C, 2 hPa to ambient pressure, preferably 70-110°C, 5-30 hPa) to obtain GVL with a purity of >99% by GC. The Hazen dye index was measured for the GVL before and after distillation.

[0084] Example 1: Cotton / elastic fiber separation Material from a white top containing elastic fibers and cotton was processed as described in Reference Example 1. The type of polymer material and experimental conditions, as well as the results, are shown in Table 1. Samples before processing ((colored) polymer material, Table 1) and after the final drying step (elastic fiber-depleted polymer material, Table 1) were analyzed, weights were determined, and IR spectroscopy was performed to demonstrate changes in the peaks before and after separation compared to known spectra for cotton, and polyurethane- and polyether-based elastic fibers.

[0085] [Table 2]

[0086] Based on IR spectroscopy, the following was shown: a) Types of elastic fibers: The elastic fibers were polyurethane and polyether based. b) IR description of the material before treatment: The material before treatment was 1730, 1707, 1637, 1592 and 1535 cm -1 The additional peaks are attributed to polyurethane and polyether based elastic fibers. c) IR description of the material after treatment: The treated material showed pure cotton with no additional peaks, clearly demonstrating that the polyurethane and polyether-based elastic fibers were completely separated from the cotton.

[0087] The IR spectra before and after treatment are compared in FIG.

[0088] Example 2: PA / elastic fiber separation Materials from beach fashion containing elastic fibers and polyamide were treated as described in Reference Example 1. The type of polymer material and experimental conditions, as well as the results, are shown in Table 2. Samples before treatment ((colored) polymer material, Table 2) and after the final drying step (elastic fiber-depleted polymer material, Table 2) were analyzed, weighed and quantified. 1 H-NMR was measured to determine the polyamide (PA) content before and after isolation, and IR spectroscopy was performed to demonstrate the change in peaks before and after isolation compared with known spectra for polyamides.

[0089] [Table 3]

[0090] The starting material was shown to consist of 83 g of polyamide per 100 g of material. 10 g of this material was treated according to the procedure of Reference Example 1, again yielding 8.3 g of elastic-free polyamide. NMR did not clearly show peaks indicative of elastic fiber, but did show 95.7 g of polyamide. This result demonstrates that elastic fiber can be completely removed from the PA / elastic fiber blended, colored beach fashion.

[0091] Based on IR spectroscopy, the following was shown: a) Types of elastic fibers: The elastic fibers were polyurethane and polyether based. b) IR description of the material before treatment: The spectrum measured before treatment showed that the blend of polyamide 6 (PA6) with polyurethane and polyether-based elastic fibers (at 1730, 1708 and 1104 cm) -1 (having its characteristic signal in c) IR description of the re-obtained PA material: Again, the measured IR spectrum of the obtained material showed that it consisted solely of PA6: no additional peaks belonging to elastic fibers were found.

[0092] A comparison of the IR spectrum of the PA obtained again after separation (treatment) and that of polyamide 6 (fresh for comparison) is shown in Figure 2, and a comparison of the IR spectra before and after treatment is shown in Figure 3.

[0093] From these, it was clearly visible that the elastic fibers were completely removed after treatment, indicating that the elastic fibers were polyurethane and polyether based.

[0094] Example 3: Separation of PA / elastic fibers from tights Material from black tights containing elastic fibers and polyamide was treated as described in Reference Example 1. The type of polymer material and experimental conditions, as well as the results, are shown in Table 3. Samples before treatment ((colored) polymer material, Table 3) and after the final drying step (polymer material depleted of elastic fibers, Table 3) were analyzed, weighed and quantified. 1 H-NMR was measured to determine the polyamide (PA) content before and after isolation, and IR spectroscopy was performed to demonstrate the change in peaks before and after isolation compared with known spectra for polyamides.

[0095] [Table 4]

[0096] Further analysis of extracted fibers: The extracted fiber material 1H-NMR analysis confirmed the complete removal of elastic fibers from the PA6.6. After drying in a vacuum at 80°C for 1 day, the material was processed in a DSM Mini Compounder (100 rpm, 290°C, 3-minute extrusion time). The material was easily processable. To evaluate the mechanical properties of the material, tensile specimens were prepared and tested according to ISO 527-2:2012. The specimens exhibited an E-modulus of 3992 MPa, higher than that of PA66 (2315 MPa), and the tensile stress at break (73 MPa) and nominal tensile strain at break (202%) were comparable to similar specimens made with PA66. In summary, this extraction method allows the material to be thermoplastically processed while retaining important mechanical properties.

[0097] The remaining GVL fraction containing elastic fiber was subjected to distillation, and the remaining residue was dried under air to obtain a solid, which was called the re-obtained elastic fiber fraction. In this re-obtained elastic fiber fraction, residual amounts of GVL were detected.

[0098] Quantitation of both fractions (re-obtained polyamide and re-obtained solid after distillation of GVL) 1 H-NMR clearly showed that complete separation of elastic fibers and polyamide could be achieved.

[0099] Based on IR spectroscopy, the following can be shown: a) Types of elastic fibers: The elastic fibers were a mixture of polyurethane containing polyester and polyurethane containing polyether and polyacrylonitrile. b) IR description of the re-obtained PA material: The measured IR spectrum of the material re-obtained after treatment showed that it consisted solely of PA 6.6. No additional peaks belonging to elastic fibers were found. The IR spectrum of the re-obtained PA after separation (treatment, IR spectrum taken twice) is shown in Figure 4 for a direct comparison with polyamide 6.6 (fresh for comparison). c) Explanation of the IR of the re-obtained elastic fibers: The IR spectrum of the re-obtained elastic fiber showed that it consisted of a mixture of polyester, polyurethane, and polyacrylonitrile. This material showed no signal for PA6.6. The material showed residual amounts of the solvent GVL. An IR spectrum for a direct comparison of both fractions (re-obtained polyamide and re-obtained elastic fiber) is shown in Figure 5. An IR spectrum for a comparison of the re-obtained PA after treatment, the re-obtained elastic fiber, and GVL is shown in Figure 6.

[0100] Example 4: Cotton / Linen / Viscose / Sorona The material (according to the manufacturer) consisted of 15% by weight of cotton, 45% by weight of linen, 22% by weight of viscose and 18% by weight of Sorona (a PTT-based elastic fiber) and was treated as described in Reference Example 1. The experimental conditions and results are shown in Table 4. Samples were analyzed before treatment ((colored) polymer material, Table 4) and after the final drying step (Sorona-depleted polymer material, Table 4) and the weights were determined.

[0101] [Table 5]

[0102] Experimental results showed that the material consisted of 12% Sorona by weight and could be removed by this process.

[0103] Comparative Examples (CE) 1-3: Separation using known solvents Comparative Examples 1-4 were carried out as described in Reference Example 1 for black tights (Example 3), except that GVL was replaced with another solvent selected from ethanol (EtOH, Comparative Example 1, Table 5), cyclohexanone (Comparative Example 2, Table 6), and ethyl lactate (Comparative Example 1, Table 7). Additionally, when EtOH (Comparative Example 1) was used, the separation was carried out at 70°C due to its boiling point.

[0104] [Table 6]

[0105] [Table 7]

[0106] [Table 8]

[0107] Mass balance analysis: In the comparative example, the same material as in Example 3 (black tights, a mixture of polyamide and elastic fibers (including polyurethanes with polyester, polyurethanes with polyether and polyacrylonitrile)) was used. After treatment with GVL in Example 3, complete separation could be demonstrated, and according to these results, the starting material consisted of 39% by weight of elastic fibers.

[0108] Masses weighed before and after application of EtOH, cyclohexanone and ethyl lactate showed that essentially no elastic fibers were removed, as was also confirmed by IR spectroscopy: 1) Explanation of IR of re-obtained material - EtOH From the material obtained again, 1730 cm -1 (Polyurethane) and 2240cm -1 Typical peaks for PA6.6 were observed, along with additional peaks for (acrylonitrile), clearly indicating that separation of polyamide and elastic fibers was not complete, if at all. 2) IR description of the re-obtained material - Cyclohexanone From the material obtained again, 1733 cm -1 (Polyurethane) and 2240cm -1Typical peaks for PA6.6 were observed, along with additional peaks for (acrylonitrile), clearly indicating that separation of polyamide and elastic fibers was not complete, if at all. 3) Explanation of IR of re-obtained material - Ethyl lactate From the material obtained again, 1733 cm -1 (Polyurethane) and 2240cm -1 Typical peaks for PA6.6 were observed, along with additional peaks for (acrylonitrile), clearly indicating that separation of polyamide and elastic fibers was not complete, if at all.

[0109] FIG. 7 shows IR spectra comparing Comparative Examples 1 to 3 and the PA fraction of Example 3.

[0110] References International Publication No. 2016 / 12755A1 Brochure Wenjun Chen,Yuechao Yang,Xue Lan,Baolong Zhang,Xiaogang Zhang and Tiancheng Mu in Green Chem.,2021,23,4065 International Publication No. 2013 / 032408A1 Brochure International Publication No. 2022 / 115602A1 Brochure

Claims

1. (i) polyamide and / or cellulosic polymer; (ii) Elastic fibers, wherein at least 90% by weight of the elastic fibers are polyurethane-based elastic fibers, based on 100% by weight, which is the total weight of the elastic fibers.

1. A method for separating a polymer blend comprising: (a) providing the polymer blend and providing a solvent comprising gamma-valerolactone; (b) contacting the solvent comprising γ-valerolactone with the polymer blend at a temperature T1 of less than 170°C, thereby obtaining a solvent enriched in dissolved elastic fibers and a residue of the polymer blend depleted of the elastic fibers and comprising the polyamide and / or the cellulosic polymer.

2. 2. The method for separating polymer blends according to claim 1, wherein the elastic fibers of (ii) comprise one or more polyurethane-based elastic fibers, the elastic fibers preferably comprising a polyurethane-based (block) copolymer.

3. 3. The method for separating a polymer blend according to claim 1 or 2, wherein at least 95% by weight of the elastic fibers are polyurethane-based elastic fibers, based on 100% by weight of the total weight of the elastic fibers.

4. 4. A process for separating a polymer blend according to any one of claims 1 to 3, wherein the solvent comprising gamma valerolactone is a mixture of gamma valerolactone and, optionally, water and a log K in the range of -1.6 to +1.

6. ＯＷ and one or more solvents selected from the group consisting of organic solvents having

5. 5. A method for separating the polymer blend of any one of claims 1 to 4, wherein the polyamide is selected from the group consisting of polyamide 6, polyamide 6.6, and a mixture of polyamide 6 and polyamide 6.

6.

6. 6. A method for separating a polymer blend according to any one of claims 1 to 5, wherein the cellulosic polymer is selected from the group consisting of natural cellulosic polymers, synthetic cellulosic polymers, and mixtures of one or more natural cellulosic polymers with one or more synthetic cellulosic polymers, the natural cellulosic polymers are preferably selected from the group consisting of cotton, cellulose, lignin, linen, viscose, and mixtures of two or more thereof, the synthetic cellulosic polymer is preferably viscose, the cellulosic polymer preferably comprises at least cotton, and more preferably at least 65 wt%, more preferably at least 70 wt%, more preferably at least 75 wt%, more preferably at least 80 wt%, more preferably at least 85 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, of the cellulosic polymer is cotton, based on 100 wt%, which is the total weight of the cellulosic polymer, and more preferably the cellulosic polymer is cotton.

7. A method for separating a polymer blend according to any one of claims 1 to 6, wherein T1 is a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 110 to 165°C, more preferably a temperature in the range of 120 to 150°C, preferably when the elastic fibers of (ii) comprise one or more polyurethane-based elastic fibers, T1 is preferably a temperature in the range of 110 to less than 170°C, more preferably a temperature in the range of 110 to 165°C, more preferably a temperature in the range of 120 to 150°C, and / or when the elastic fibers of (ii) comprise one or more polyester-based elastic fibers, T1 is preferably a temperature in the range of 110 to less than 170°C, preferably a temperature in the range of 130 to 165°C, more preferably a temperature in the range of 140 to 165°C.

8. A method for separating a polymer blend according to any one of claims 1 to 7, comprising the steps of: (c) separating the solvent enriched in dissolved elastic fibers obtained in (b) from the residue of the polymer blend, preferably by a physical separation method, thereby obtaining a separated solvent enriched in dissolved elastic fibers compared to the solvent provided in (a) and the residue of the polymer blend depleted in elastic fibers and comprising the polyamide and / or the cellulosic polymer.

9. A method for separating a polymer blend according to any one of claims 1 to 8, comprising the steps of: (d) optionally washing the elastic fiber-depleted residue of the polymer blend comprising the polyamide and / or the cellulosic polymer obtained in (c), thereby obtaining a washed residue of the polymer blend comprising the polyamide and / or the cellulosic polymer; (e) drying the polymer blend residue obtained in (c) or the washed polymer blend residue obtained in (d), thereby obtaining a dried polymer blend residue comprising the polyamide and / or the cellulosic polymer.

10. 10. The method for separating a polymer blend according to claim 9, wherein step (d) comprises: (d.1) optionally washing the residue of the polymer blend obtained in (c) with a wash solution comprising a solvent comprising gamma-valerolactone and removing the wash solution to obtain a pre-washed residue of the polymer blend; (d.2) optionally washing the pre-washed residue of the polymer blend obtained in (d.1) with a solvent selected from the group consisting of γ-valerolactone, methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water or a mixture of two or more of these solvents, preferably a solvent comprising at least acetone, more preferably acetone, is used, thereby obtaining a washed residue of the polymer blend comprising the polyamide and / or the cellulosic polymer.

11. 11. A method for separating a polymer blend according to any one of claims 1 to 10, wherein the residue of the polymer blend comprises a cellulosic polymer, the cellulosic polymer obtained in (d), (d.2) or (e) being further separated by: - mechanical treatment, preferably selected from the group consisting of crushing, stirring, shredding, tearing and combinations of two or more of these treatments; - a thermal treatment, preferably selected from the group consisting of freezing, heating or boiling, and combinations of two or more of these treatments, preferably in combination with the application of excess pressure (excess pressure = pressure above 1013 mbar); - incubation in an aqueous alkaline medium, preferably comprising water and one or more alkaline salts, preferably sodium salts selected from the group consisting of sodium hydroxide, sodium carbonate, sodium monochloroacetate and mixtures of two or more thereof; incubation in an acidic medium, preferably in one or more acids selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid and formic acid; - incubation in an ionic liquid, preferably in one or more ionic liquids selected from the group consisting of 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]) and 1,5-diazabicyclonon-5-enium acetate ([DBNH][OAc]); - incubation in N-methylmorpholine-N-oxide (NMMO); - ultrasonic treatment; - irradiation; - addition of an enzyme preferably selected from the group consisting of cellulase, protease, pectinase, glucosidase, glucanotransferase, PET hydrolase (PETase) and lipase, and mixtures of two or more of these enzymes, more preferably selected from the group consisting of β-1,4-exoglucanase, β-1,4-endoglucanase, β-1,4-cellobiohydrolase, β-glucosidase, pyrrolase, and mixtures of two or more of these enzymes; and - microbial cultivation, preferably by adding cellulolytic bacterial or fungal strains or mixed cultures; The method further comprising post-processing by applying one or more treatments selected from the group consisting of:

12. 11. A process for separating a polymer blend according to any one of claims 1 to 10, wherein when the residue of the polymer blend comprises a polyamide, the process further comprises post-treating the polyamide obtained in (d), (d.2) or (e) by a process selected from the group consisting of depolymerizing the polyamide into their oligomeric and / or monomeric fragments, mechanical recycling, re-granulation, compounding, and a combination of two or more of these processes.

13. A polyamide and / or cellulosic polymer obtained or obtainable from the method according to any one of claims 1 to 12.

14. - As a combustible material in heating and power plants; as a feedstock in anaerobic digestion plants, preferably biogas reactors; - as a substrate for wastewater treatment plants; - as input for biorefineries, preferably biofuel plants; as input material in gasification plants, preferably for producing synthesis gas or hydrogen; - as input material in pyrolysis reactions or pyrolysis plants; as an input material in the HTC process; and / or - Use of the cellulosic polymer according to claim 13 as a feedstock in a bacterial or fungal fermentation process.

15. 14. Use of the polyamide polymer of claim 13 for preparing textiles, automotive applications, industrial fibers, or engineering plastics.

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