Manufacturing method of regenerated cellulose yarn from recycled waste materials

Abstract

1. A method for producing cellulose yarn from recycled cellulosic material, the method comprising the steps of: (a) dissolving the recycled cellulosic material in a molten ionic liquid; and (b) adapting conditions such that an active substance dissolved or dispersed in the molten ionic liquid, or an active substance generated in situ in the molten ionic liquid, is initially present in the recycled cellulosic material and acts to degrade non-cellulosic material contained in the molten ionic liquid upon dissolution of the recycled cellulosic material, wherein the active substance can already be present during (a) or can be added after (a) and before or during (b).

Description

[Technical field]

[0001] The present invention relates to a method for conditioning cellulose-containing recycled materials based on dissolution in ionic liquids and the decomposition and color removal and / or modification of molecular weight distribution of cellulose polymers by the addition of active substances. The method allows the direct processing of recycled materials and subsequent spinning to obtain fibers. The method is advantageous in that a wide range of post-consumer and post-industrial recycled goods can be processed for reuse in the production of regenerated cellulose fibers. [Background technology]

[0002] Recycling in the textile sector is becoming increasingly important, but its implementation and impact are still far from its ultimate potential. In fact, the majority of recycled textiles are not recycled to the same level again, but are used in lower level applications after recycling, for example as building materials (insulation). There is a need to provide circular methods that allow the recycling of textiles so that recycled materials can be reused to the highest possible level, ideally towards the manufacture of textiles of the same kind as those used as recycled feedstock.

[0003] The sustainability profile of regenerated cellulose yarns can be further improved by the use of cellulose sources based on recycled cellulose feedstocks, such as post-industrial and post-consumer apparel fabrics such as cotton, viscose, lyocell, and other forms of cellulose-containing articles. Additional cellulose-containing streams (e.g., agricultural waste, pulp, bacterial cellulose, algae cellulose, etc.) can also be used as cellulose sources.

[0004] The main challenges in using post-consumer goods are: · Clothing comes in a wide variety of colors due to the use of dyes; The introduction of impurities such as fats, oils and mineral substances during use of the article; The presence of non-cellulosic components in the article (e.g. synthetic blend components, sewing yarns, surface treatments, zippers, buttons, etc.).

[0005] Conventional processing techniques to address the above challenges involve intensive scouring and bleaching steps that are water and energy intensive to provide clean, uncolored cellulose.

[0006] Conventional approaches to remove non-cellulose components involve mechanical degradation of the macroscopic components and selective dissolution of various fibrous components.

[0007] Patent document 1 relates to a method for the preparation of regenerated biopolymers in the form of carbohydrates, using a solvent system comprising a biopolymer dissolved therein. The solvent system is based on a molten ionic liquid and optionally a protic solvent or a mixture thereof. The biopolymer dissolved in the solvent system is precipitated in a coagulation medium, which medium comprises a protic coagulant or a mixture of protic coagulants. The method according to the invention is characterized in that the surface tension σ of the coagulant or the mixture of coagulants is 99% to 30% of the surface tension σ of water, the surface tension being measured at a temperature of 50° C. according to ASTM D 1590-60. The method according to the invention is economical, flexible and leads to advantageous products, in particular in the form of short fibres, which do not fibrillate and have an advantageous wet-dry strength ratio.

[0008] Patent Document 2 discloses a method for recovering waste textiles using ionic liquids. This method includes the following steps: 1) pretreatment of waste textiles: crushing waste textiles to obtain pretreated waste textiles; 2) swelling with water and dissolving in ionic liquid: mixing and stirring pretreated waste textiles, ionic liquids and water under vacuum conditions to obtain a cellulose-containing liquid. After pretreatment of waste textiles and swelling in water, the dissolution process is uniform and gentle, the dissolution efficiency is high, the effect is good, and the insoluble matter is completely separated from the waste textiles. The cellulose solution obtained by dissolution can be used to produce regenerated cellulose raw materials with excellent performance, and the polyester obtained by separation can serve as recycled polyester raw materials. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] U.S. Patent No. 8,841,441 [Patent Document 2] China Patent Publication No. 106146877 Summary of the Invention

[0010] Regenerated cellulose yarns produced with ionic liquids (ILs) can offer attractive fiber properties and a better sustainability profile (e.g., reduced global warming potential, reduced energy usage, biodegradability) compared to fibers made from synthetic polymers such as polyester and polyamide.

[0011] Conventional approaches that address the above significant challenges for recycling require separate processing steps prior to and separate from the production of the ionic liquid cellulose dope and subsequent fiber spinning.

[0012] The approach presented herein provides a means to directly treat recycled cellulose-containing articles in a medium comprising ionic liquids to achieve the following: Direct dissolution of recycled cellulose-containing articles to produce dope for subsequent fiber spinning; Dissolution first serves to separate and remove water-insoluble components such as synthetic fibers and mineral-based substances; · Active substances dispersed in ionic liquids (or generated in situ) serve to degrade various dyes associated with cellulose, as well as fats and other organic impurities; · (Inert inorganic) absorbents can be homogeneously dispersed in the IL to specifically absorb impurities, e.g. dyes and other unwanted components. The loaded absorbents can be removed from the cellulose-IL solution by filtration and reused after a suitable regeneration process.

[0013] Active materials can also be selected to reduce the molecular weight of the cellulose polymer chains to aid in subsequent fiber spinning. Molecular weight reduction can be achieved by the introduction of ozone or other active gases into the IL, exposure to short wavelength radiation, e.g., UV light, or photocatalysis in the presence of a catalyst.

[0014] After dissolution of the cellulosic material in the ionic liquid, active reagents (e.g., hydrogen peroxide and / or enzymes and / or catalytic salts) are added and the mixture is heated with stirring to a temperature of 40-120°C and held at that temperature for 0.5-24 hours to achieve the desired decolorization. The resulting solution can then be heated / cooled to achieve the desired target temperature before it can be used directly in the fiber spinning process.

[0015] The main advantages of the proposed method are: 1. A wide variety of dyes can be directly decomposed and / or removed by specific absorbents in the ionic liquid treatment medium, which can be directly used for subsequent fiber spinning. A wide range of recycling sources can be used to produce new uncolored yarns.

[0016] 2. The breakdown of fats, oils and other organic impurities that would normally affect the quality of the yarn.

[0017] 3. Cellulose is selectively dissolved and insoluble components (e.g., synthetic polymer components, mineral-based materials) are separated.

[0018] 4. Direct processing in the ionic liquid medium used for subsequent fiber spinning avoids traditional intensive pre-treatment steps that would normally be water and energy intensive, further improving the sustainability profile of the recycling pathway. The resulting processing pathway requires fewer processing steps and allows for more direct utilization of recycled waste materials containing cellulosic components.

[0019] 5. The use of ionic liquids and fiber spinning processes described in WO2007076979 and WO2009062723, the disclosures of which are incorporated herein by reference, provides the basis for obtaining advantageous regenerated cellulose fibers using ionic liquids that tolerate significant presence of protic components, including water. This process advantageously allows for pretreatment actives that provide in situ decolorization and impurity degradation / absorption without affecting the performance of subsequent fiber spinning. This pretreatment would not be feasible with ionic liquid systems and fiber spinning processes that tolerate less water content.

[0020] 6. The use of catalytic chemicals (enzymes, ozone, short wavelength radiation) rather than the stoichiometric chemicals (e.g. NaOH) currently used to adjust the degree of polymerization (DP) of cellulose, and the in situ generation of H2O2 in direct proximity to the material to be bleached, reduces the amount of H2O2 required compared to bulk phase delivery, requiring fewer chemicals.

[0021] One important feature of the present invention is that it has surprisingly been found that ionic liquids can also be used to dissolve and disperse active substances that can tolerate up to a certain amount of water or other protic solvents for dissolving and spinning cellulose, while at the same time achieving excellent fiber properties and also allowing the introduction of catalytic components that do not raise the level of water or other protic solvent to a level that would adversely affect proper fiber spinning and therefore the fiber properties.

[0022] Decomposition / absorption of dyes and organic impurities is possible as follows: Direct bleaching / decolorization of dyes associated with recycled cellulose in an ionic liquid medium used to dissolve the cellulose components.

[0023] Possible approaches include: Organic and inorganic absorbents can be added to absorb impurities, then filtered and removed for recycling; adding hydrogen peroxide or ozone to a solution of cellulose in an ionic liquid, or exposing it to short wavelength light, or allowing photocatalysis to occur; Adding enzymes to ionic liquid solutions of cellulose produces bleaching active substances like hydrogen peroxide in situ (e.g., cellobiose dehydrogenase produces H2O2 locally, but peroxidase can also take up H2O2 and generate bleachable radicals); Enzymes such as laccase are added to decolorize and destroy impurities.

[0024] In either case, the hydrogen peroxide is decomposed into residual water (the ionic liquid process tolerates the presence of residual water), oxygen, and colorless residual decomposition by-products, which can optionally be removed directly without decomposition or by the use of adsorbents after decomposition in contact with the ionic liquid treatment medium.

[0025] The reduction of the molecular weight of the cellulose is advantageous and can be achieved as follows: · The molecular weight of the cellulose polymer has a direct impact on the fiber spinning performance and also on the mechanical properties of the resulting yarn; · For some recycled cellulosic feedstocks (e.g., cotton-rich clothing), it may be advantageous to narrow the molecular weight distribution of the cellulose to enable improved fiber spinning performance and fiber properties; · The reduction in molecular weight can occur by the action of hydrogen peroxide alone and / or by the addition of other ingredients selected to cleave the cellulose polymer and reduce the average molecular weight, such as ozone, UV light or photocatalysts; Such additives may include enzymes and / or salts. The action of such additives in ionic liquid media is facilitated by the presence of water in the ionic liquid, a feature of WO2007076979 and WO2009062723, the disclosures of which are incorporated herein by reference.

[0026] The use of enzymes (e.g., laccase) to decolorize dyes is a well-established technique in detergent and laundry processing. The use of active substances, such as enzymes, to achieve the decolorization effect in an ionic liquid treatment medium is a novel feature of the present invention.

[0027] The use of hydrogen peroxide in ionic liquids for the oxidative conversion of lignocellulosic feedstocks is described in US Pat. No. 10,724,060, but the patent teaches that the action of hydrogen peroxide is directed to the decomposition of lignin, and does not address the decomposition of coloring components such as dyes associated with recycled cellulosic materials. US Pat. No. 10,724,060 also mentions the use of cellulases and / or hemicellulases, but the enzyme components are specifically selected to convert biomass from cellulose to sugar components, rather than reducing the molecular weight while retaining the properties of the cellulose polymer. It is important to note that in US Pat. No. 10,724,060, the oxidizing and enzymatic materials are contacted in an aqueous medium prior to the subsequent process step of adding the ionic liquid.

[0028] WO2016087186 and US8445704 describe the use of ionic liquids as a process medium for the chemical modification and conversion of polysaccharides, but do not address color, impurities, or cellulose molecular weight by using hydrogen peroxide / ozone, short wave radiation, photocatalysis and / or enzymes.

[0029] US Pat. No. 1,168,196 describes an approach to facilitate separation of mixed cellulose / polyester waste, but makes no provision for actively addressing color, impurities and / or molecular weight in the ionic liquid used to dissolve the cellulose components.

[0030] More generally, the present invention provides a method for producing cellulose yarn from recycled cellulose material, the method comprising the steps of: (a) dissolving recycled cellulosic material in a solution comprising at least a molten ionic liquid; (b) adapting conditions such that an active substance dissolved or dispersed in the molten ionic liquid, or an active substance generated in situ in the molten ionic liquid, is initially included in the recycled cellulosic material and acts to degrade non-cellulosic material contained in the molten ionic liquid upon dissolution of the recycled cellulosic material, the active substance can be already present during (a) or can be added after (a) and before or during (b).

[0031] The adaptation of conditions according to step (b) can be carried out in different ways, such as, for example, changing the solvent composition, adding said active substance (alone or in a carrier solvent), activating said active substance, changing the temperature, pH, changing the pressure, introducing activation energy, for example by irradiation, or a combination of such adaptations.

[0032] The term active material in the context of (b) includes any suitable material that is suitable to perform the function of degrading the non-cellulosic materials initially contained in the recycled cellulosic material, examples of which are described below.

[0033] The recycled cellulosic material is preferably selected from at least one of cellulosic waste, recycled yarn, recycled fabric, recycled tissue, recycled garment.

[0034] The non-cellulosic materials are typically selected from at least one of dyes, fats, other organic impurities such as oils, waxes and detergent residues, inorganic materials such as sand or clay, water soluble and water insoluble pigments.

[0035] After step (a) and before or after step (b), it is possible and preferred to provide a step (c) of separating impurities that are not dissolved or that are not soluble due to dissolution of the recycled cellulose material or the absorbent, which preferably comprises at least one of filtration, decantation, centrifugation and sieving.

[0036] The ionic liquid solution preferably comprises a protic liquid, preferably water.

[0037] The active substance is preferably selected from the group of absorbents, cleavage agents, such as biological cleavage agents, physical cleavage agents and chemical cleavage agents, the absorbents are preferably selected from the group of substances that adsorb at least one of dyes, fat impurities and other organic impurities, the cleavage agents are preferably selected from the group of direct cleavage agents or activatable cleavage agents, preferably cleavage agents activated by irradiation with electromagnetic radiation, and the cleavage agents can be selected from the group of enzyme systems, such as proteases, oxidoreductases, amylases, laccases and lipases, ozone, peroxides, photocatalysts and combinations thereof. In the examples described below, hydrogen peroxide is used as the active substance. However, this is only one option, and the above-mentioned substances can perform the function of the active substance in a complementary and / or alternative manner to this example using hydrogen peroxide.

[0038] Preferably, a system for reducing the molecular weight of the cellulose polymer, preferably selected from the group of enzyme systems such as cellulases or hemicellulases or cellulose oxidases, in particular endoglucanases, exoglucanases, or cleavage agents activated by irradiation with electromagnetic radiation, or strong bases, or combinations thereof, is either initially included in the ionic liquid or is replenished after step (b) or, if present, after (c).

[0039] In step (b), the temperature is preferably increased to a range of from 40 to 120° C. and maintained at this temperature for a period preferably in the range of from 0.5 to 24 hours.

[0040] After step (b) or after step (c), cellulose yarns can be spun directly from the cellulose dissolved in the ionic liquid.

[0041] The molten ionic liquid further preferably comprises a protic solvent or a mixture of protic solvents, and when the protic solvent is only water, water is present in the solution system in an amount of more than 5 wt %; and the cellulose dissolved in the molten ionic liquid is precipitated in a coagulation medium comprising a solvent that does not dissolve the cellulose and is miscible with the molten ionic liquid, the molten ionic liquid preferably comprising a cation formed from a compound comprising at least one 5- to 6-membered heterocycle and a protic solvent; and the method comprises precipitating the dissolved cellulose in the form of a carbohydrate in a coagulation medium comprising a solvent that does not dissolve the cellulose and is miscible with the molten ionic liquid, wherein The protic solvent is 1) water as the only protic solvent present in the solution system in an amount of at least 5 or 6% by weight; 2) at least 0.1% by weight of the solution system of at least one protic solvent selected from the group consisting of alcohols, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, amyl alcohol, and linear and branched alcohols and higher linear and branched alcohols; and 3) at least one protic solvent selected from the group consisting of water, alcohols, carboxylic acids or amines, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, amyl alcohol and linear and branched alcohols and higher linear and branched alcohols; is selected from the group consisting of:

[0042] Suitable systems acting as ionic liquids are for example those described in US Pat. No. 8,163,215 or US Pat. No. 8,841,441, the disclosures of which are incorporated herein by reference with respect to ionic liquid systems.

[0043] The ionic liquid in the context of the present invention is preferably (A) General formula (I): [A] + n [Y] n - (I) [In the formula, n represents 1, 2, 3 or 4, and [A] + represents a quaternary ammonium cation, an oxonium cation, a sulfonium cation, or a phosphonium cation; [Y] n - represents a monovalent, divalent, trivalent or tetravalent anion; or (B) general formula (II) [A 1 ] + [A 2 ] + [Y] n- (IIa), where n=2; [A 1 ] + [A 2 ][A 3 ] + [y] n- (IIb), where n=3; or [A 1 ] + [A 2 ] + [A 3 ] + [A 4 ] + [Y] n- (IIc), where n=4; [In the formula, [A 1 ] + , [A 2 ] + , [A 3 ] + and [A 4 ] +are independent of each other, [A] + [Y] is selected from the group listed above. n- has the meaning given under (A).

[0044] Possible is, for example, the use of 1-ethyl-3-methylimidazolium chloride. This is also used in the examples, but this is only one option, and the ionic liquid substances mentioned in this general section can likewise act in this way in a complementary (ionic liquid mixture) and / or alternative manner to this example using 1-ethyl-3-methylimidazolium chloride. In particular, systems based on methylimidazolium, in particular systems based on 1-ethyl-3-methylimidazolium, thus fluoride, acetate or dicyanamide, (C2H5)(CH3)C3H3N + 2·N(CN) - Systems based on 1-ethyl-3-methylimidazolium with various anions such as 2, as well as 1-butyl-2,3-dimethylimidazolium or 1-butyl-3,5-dimethylpyridinium, 1-butyl-3-methylimidazolium, e.g. 1-butyl-3,5-dimethylpyridinium bromide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or combinations thereof apparently perform the same function.

[0045] Ionic liquid cation [A] +Suitable compounds for forming are known, for example, from DE 10202838 A1. Such compounds can thus contain oxygen, phosphorus, sulfur or especially nitrogen atoms, for example at least one nitrogen atom, preferably 1 to 10 nitrogen atoms, particularly preferably 1 to 5, very particularly preferably 1 to 3, in particular 1 to 2 nitrogen atoms. They can also optionally contain further heteroatoms, such as oxygen, sulfur or phosphorus atoms. Nitrogen atoms are suitable as carriers of the positive charge of the cations of the ionic liquids, from which protons or alkyl radicals can be transferred in equilibrium to the anions to generate electrically neutral molecules.

[0046] Ionic liquid systems can also be used with cationic 1,5,7-triazabicyclo[4.4.0]dec-5-enium [TBDH] as described, for example, in WO 2018 / 138416, which is also incorporated herein by reference as it relates to ionic liquid systems. + a) a moiety, b) a moiety and c)

[0047] [ka]

[0048] and an anion selected from the group consisting of:

[0049] According to yet another preferred embodiment, the molten ionic liquid comprises a protic solvent or a mixture thereof, and the method comprises precipitating cellulose in a coagulation medium, wherein a protic coagulant or a mixture of protic coagulants is present in the coagulation medium, and the surface tension σ of the protic coagulant or mixture of protic coagulants is between 99% and 30% of the surface tension σ of water, each surface tension being within the range of ASTM D 1590-60 at a temperature of 50 ° C., preferably the protic coagulant is selected from 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 2-ethyl-1-hexanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2,3-propanetriol, 2,2-dimethyl-1,5-propanediol, cyclohexanol, diethylene glycol, triethylene glycol and mixtures thereof, more preferably the coagulation medium does not contain more than 5% carboxylic acid.

[0050] According to a further aspect, the present invention relates to a cellulose yarn produced using the above-mentioned method.

[0051] According to yet another aspect, the present invention relates to the use of the above-mentioned cellulose yarns for the manufacture of textiles, in particular clothing.

[0052] The cellulose yarns produced can be used directly in a wide variety of textile processes, such as bulking, twisting, covered yardage (core spun yarns), knitting, weaving, seamless, circular knitting with other yarns (e.g. cotton, nylon, polyester, polypropylene, cellulosic, wool, silk, polyurethane), warp knitting, beaming, staple fiber, nonwovens, etc. The cellulose yarns produced can be used directly in a wide variety of textile forms, such as denim, hosiery, underwear, sportswear, fashion, shoes, sewing thread, upholstery, home textiles, industrial textiles, etc.

[0053] Further embodiments of the invention are defined in the dependent claims. [Brief description of the drawings]

[0054] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the drawings are for explaining the preferred embodiments of the present invention and are not intended to limit the present invention. [Figure 1] FIG. 1 shows schematic process steps of conventional processing of recycled cellulose to regenerated cellulose fibers in comparison with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] In the top part of Figure 1, a schematic diagram of conventional pretreatment of recycled cellulose material to remove color and impurities followed by dissolution in ionic liquid and subsequent fiber spinning is shown. In contrast, in the bottom part of the present invention, the recycled cellulose is directly dissolved in ionic liquid, allowing color and impurities to be treated directly in the ionic liquid dope, followed by fiber spinning. The present invention allows for reduced process complexity and reduced energy and water usage compared to conventional methods.

[0056] Experimental Example: A knitted fabric consisting of 100% viscose yarn was dyed with a red azo dye (Basic Red 46) using a laboratory exhaust dyeing apparatus, followed by cleaning and laundering. A small (30 cm x 30 cm) portion of the fabric (approximately 10 g) was manually cut from the material and further cut into pieces of approximately 3 cm x 3 cm. In a glass beaker, 96 g of ionic liquid (1-ethyl-3-methylimidazolium chloride) and 4 g of deionized water were prepared. The ionic liquid mixture was heated and maintained at 90°C. The fabric piece was manually mixed into the molten ionic liquid (IL) until the added materials dissolved to form a homogenous solution. The initially prepared solution was observed to have an intense red color. Hydrogen peroxide in the amount of 4 g was gradually added to the ionic liquid solution while maintaining gentle stirring with a magnetic stirrer. The stirred solution was maintained at 90°C for 6 hours. The resulting solution appeared pale red in color and was observed to have a significant loss in color intensity, consistent with the decomposition of the azo dye species associated with the dissolved cellulose.

[0057] The decolorized cellulose IL solution produced above was charged to a heated extrusion chamber and held at 90° C. The exit nozzle orifice of the chamber was positioned above a water coagulation bath held at 20° C. with an air gap separation distance of 20 mm. Regenerated cellulose monofilaments were produced by injecting the cellulose IL solution into the coagulation bath and drawing the solidified cellulose filaments from the coagulation bath at approximately 20 m / min into a subsequent water wash bath held at 60° C. The regenerated cellulose filament material produced exhibited a pale red color compared to the deep red filaments produced without hydrogen peroxide conditioning.

Claims

1. 1. A method for producing cellulose yarn from recycled cellulose material, the method comprising the steps of: (a) dissolving recycled cellulosic material in a solution comprising at least a molten ionic liquid; (b) adapting conditions such that an active substance dissolved or dispersed in the solution comprising the molten ionic liquid, or generated in situ in the solution comprising the molten ionic liquid, acts to degrade non-cellulosic material initially contained in the recycled cellulosic material and contained in the solution comprising the molten ionic liquid upon said dissolution of the recycled cellulosic material, wherein the active substance can be already present during step (a) or can be added after step (a) and before or during step (b).

2. The method of claim 1 , wherein the recycled cellulosic material is selected from at least one of cellulosic waste, recycled yarn, recycled fabric, recycled tissue, recycled clothing, and other cellulose-containing waste streams.

3. 3. The method of claim 1 or 2, wherein the non-cellulosic material is selected from at least one of dyes, fats, other organic impurities such as oils, waxes, and detergents and their residues, inorganic materials such as sand, clay, water-soluble and water-insoluble pigments.

4. A method as described in claim 1 or 2, wherein after step (a) and before or after step (b), there is a step (c) of separating undissolved or insoluble impurities resulting from the dissolution of the recycled cellulose material or absorbent.

5. The method of claim 1 or 2, wherein the solution containing an ionic liquid comprises a protic liquid.

6. 3. The method of claim 1 or 2, wherein the active substance is selected from the group of absorbents or cleaving agents including biological cleaving agents, physical cleaving agents and chemical cleaving agents, wherein the absorbents can be selected from the group of substances that adsorb at least one of dyes, fatty impurities and other organic impurities, and the cleaving agents can be selected from the group of direct cleaving agents or activatable cleaving agents including those activated by irradiation with electromagnetic radiation, and wherein the cleaving agents can be selected from the group of enzyme systems including proteases, amylases, laccases, oxidoreductases and lipases, ozone, peroxides, photocatalysts and combinations thereof.

7. 3. The method of claim 1 or 2, wherein a system for reducing the molecular weight of the cellulose polymer is either initially included in the solution containing the ionic liquid or is replenished after step (b) or after step (c), if present.

8. The method of claim 1, wherein in step (b), the temperature is increased to a range of 40 to 120°C and maintained at this temperature for a period of time ranging from 0.5 to 24 hours.

9. A method as described in claim 1 or 2, wherein after step (b) or after step (c), the cellulose yarn is directly spun from the cellulose dissolved in a solution containing the ionic liquid.

10. 3. The method of claim 1, wherein the molten ionic liquid comprises a protic solvent or a mixture of protic solvents, and when the protic solvent is only water, the water is present in the solution system in an amount greater than 5 wt %; and wherein the cellulose dissolved in the molten ionic liquid is precipitated in a coagulation medium comprising a solvent that does not dissolve the cellulose but is miscible with the molten ionic liquid; and the method comprises precipitating the dissolved cellulose in the form of a carbohydrate in a coagulation medium comprising a solvent that does not dissolve the cellulose but is miscible with the molten ionic liquid.

11. The protic solvent is 1) water as the only protic solvent present in the solution system in an amount of at least 5 or 6% by weight; 2) at least 0.1% by weight of the solution system of at least one protic solvent selected from the group consisting of alcohols, carboxylic acids, or amines, such as methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol, and amyl alcohol, and linear and branched alcohols, and higher linear and branched alcohols; and 3) Water and at least one protic solvent selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol The method of claim 10, wherein the compound is selected from the group consisting of:

12. 3. The method of claim 1 or 2, wherein the molten ionic liquid comprises a protic solvent or a mixture thereof, the method comprising precipitating cellulose in a coagulation medium, wherein a protic coagulant or a mixture of protic coagulants is present in the coagulation medium, and wherein the surface tension σ of the protic coagulant or mixture of protic coagulants is between 99% and 30% of the surface tension σ of water, each surface tension being measured according to ASTM D 1590-60 at a temperature of 50°C.

13. 13. The method of claim 12, wherein the protic coagulant is selected from 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 2-ethyl-1-hexanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2,3-propanetriol, 2,2-dimethyl-1,5-propanediol, cyclohexanol, diethylene glycol, triethylene glycol, and mixtures thereof.

14. A cellulose yarn produced using the method of claim 1 or 2.

15. Use of the cellulose yarn of claim 12 for the manufacture of textiles, including clothing.

16. The method of claim 4, wherein step (c) of separating undissolved or non-soluble impurities comprises at least one of filtration, decantation, centrifugation, and sieving.

17. The method of claim 5, wherein the solution containing the ionic liquid contains water in an amount greater than 2% by weight, or greater than 4% by weight, or greater than 5% by weight.

18. The method of claim 7, wherein the system for reducing the molecular weight of the cellulose polymer is selected from the group consisting of an enzyme system containing cellulase, or hemicellulase, or cellulose oxidase, and containing exoglucanase and / or endoglucanase, or a cleaving agent activated by irradiation with electromagnetic radiation, or a strong base, or a combination thereof.

19. The method of claim 10, wherein the molten ionic liquid comprises a cation formed from a compound containing at least one five- or six-membered heterocycle and a protic solvent.

20. The method of claim 13, wherein the solidification medium does not contain more than 5% carboxylic acid.

21. Use according to claim 15 for the direct manufacture of textiles in textile processes including bulking; twisting; covered yarding; knitting; weaving; seamless; circular knitting with other yarns including cotton, nylon, polyester, polypropylene, cellulosic, wool, silk, polyurethane; warp knitting; beaming; staple fiber; nonwovens, wherein the textiles may be selected from the group consisting of denim, hosiery, underwear, sportswear, fashion, shoes, sewing thread, upholstery, household textiles, and industrial textiles.

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