Process for preparing polyester fibers from polyester recycled from polymer blends

Abstract

In a first aspect, the present invention relates to a process for preparing a polyester fiber comprising providing a polymer blend comprising (i) a polyester and (ii) one or more components selected from the group consisting of a second polymer, a third polymer, a colorant and a filler, wherein the second polymer and the third polymer are different from each other and from the polyester of (i). The method comprises a step (e) in which the fibers are prepared from the precipitated polyester.

Description

[0001] In a first aspect, the present invention relates to a method for preparing polyester fibers, the method comprising providing a polymer blend comprising (i) a polyester and (ii) one or more components selected from the group consisting of a second polymer, a third polymer, a colorant, and a filler, wherein the second polymer and the third polymer are different from each other and different from the polyester of (i); the method comprising: (a) providing the polymer blend and providing a solvent system; (b) optionally contacting the polymer blend with the solvent system at a temperature T1 < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof, and a residue of a polymer blend depleted in the second polymer and / or colorant and optionally filler or a portion thereof and comprising polyester, optionally a third polymer and optionally filler or a portion thereof; (c) contacting the polymer blend provided in (a) or the residue of the polymer blend obtained optionally in (b) with the solvent system at a temperature T2 > 170°C to obtain a solvent system rich in (a) the second polymer and / or colorant and optionally filler or a portion thereof, and comprising polyester, optionally a third polymer and optionally filler or a portion thereof; and (c) contacting the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) with the solvent system at a temperature T2 > 170°C to obtain a polymer blend rich in (a) the second polymer and / or colorant and optionally filler or a portion thereof, and comprising polyester, optionally a third polymer and optionally filler or a portion thereof; and (d) contacting the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) with the solvent system at a temperature T2 > 170°C to obtain a polymer blend rich in (a) the third polymer and / or filler or a portion thereof. The invention comprises (c) a solvent system rich in dissolved polyester and optionally containing filler or a portion thereof, and a residue of a polymer blend, the residue being polyester-poor and optionally containing a third polymer and optionally containing filler or a portion thereof; (d) precipitating polyester from the solvent system rich in dissolved polyester obtained in (c), thereby obtaining precipitated polyester and a solvent system poor in dissolved polyester and optionally containing filler or a portion thereof; and (e) preparing fibers from the precipitated polyester obtained in (d). A second aspect of the invention relates to a polyester fiber obtained or available by the method of the first aspect; and a third aspect relates to the use of the polyester fiber of the second aspect for preparing textiles. In a fourth aspect, the invention relates to a method for preparing a product, the method comprising (I) providing the polyester of the second aspect; and (II) preparing textiles from the polyester provided in (I). A fifth aspect of the invention relates to a method, preferably according to the method of the first aspect, comprising the additional step of converting a residue available or obtained by the method of the first aspect to obtain one or more monomers, polymers, or polymer products. Background Technology

[0002] Over the past few decades, the demand for polymer materials has increased dramatically. However, poor biodegradability has led to a large amount of plastic waste, which is often incinerated in Europe, losing valuable materials and generating huge CO2 emissions. Even worse, some materials end up in landfills due to poor biodegradability. Polyester-based polymer materials have been widely used in the packaging sector, such as in beverage or food packaging. Today, the vast majority of food and beverages are packaged in plastic bottles and containers made of polyester materials, such as polyethylene terephthalate (PET). PET is also a major component of clothing today. Given that these materials typically have poor biodegradability and are still valuable products, the recycling and reuse of these plastics is highly desirable.

[0003] Although recycling processes have been employed to transform waste materials into new production materials, many problems remain associated with the recycling and recovery of polymer materials. Waste packaging often comprises mixtures of different polymer materials that also contain, for example, colorants. The same applies to textiles, which also contain significant amounts of colored polymer materials. Therefore, to enable the recycling of polymer materials, they are typically separated based on their color and / or composition. However, this sorting method is labor-intensive and / or requires the use of sorting machines. Regarding the removal of colorants, EP 2 784 110 A1 describes the removal of organic colorants from polyethylene terephthalate (PET) flakes from shredded PET bottles by extracting PET flakes with ethylene glycol under ambient pressure and at the boiling temperature of ethylene glycol. US 10,876,240 B2 relates to the decolorization of dyed polyesters using gaseous propylene glycol methyl ether. DE 2223466 A1 discloses a method for separating a substance from a substrate using a solvent at elevated temperatures, wherein the substrate is heated by means of condensed vapors of a liquid miscible with the solvent but not dissolving the substrate, and subsequently, the heated substrate is treated with a solvent, thereby separating the substance from the substrate. While several methods for removing colorants from polyesters are known, these methods still have drawbacks: the depolymerization or transesterification of colored polymer materials provides monomers and / or other esters, which must be extensively purified by filtration, crystallization, or distillation. This makes the method very expensive. If decolorization is not achieved, the product quality is low and it can no longer be used in high-value applications. Furthermore, additional components present in the blend (such as other polymers) are interfering or cannot be removed like colorants. Another disadvantage is the need to use toxic solvents and / or the need to use large quantities of solvent. A method for recovering polymer materials and separating polymer blends containing not only polyesters but also other polymers involves combining the dissolution and precipitation of the polymer material. WO 2016 / 12755 A1 discloses the extraction of polyester from packaging, wherein a first solvent is used to remove colorants and a second solvent is used to dissolve the polyester. Chen et al. (Wenjun Chen, Yuechao Yang, Xue Lan, Baolong Zhang, Xiaogang Zhang, and Tiancheng Mu, Green Chem., 2021, 23, 4065) describe a method for dissolving and accelerating the alkaline hydrolysis of PET. WO 2022 / 221832 A1 describes a method for treating polyethylene terephthalate (PET) streams, wherein a polar solvent is used to dissolve the PET.Polar solvents are defined based on the Hansen parameter, where the three-dimensional rectangular Hansen space is defined by a parameter (δD) representing the energy of intermolecular dispersion forces in the range of 15 to 20, a parameter (δP) representing the energy of intermolecular dipole intermolecular forces in the range of 4 to 20, and a parameter (δH) representing the energy of intermolecular hydrogen bonds in the range of 3 to 10. However, according to this definition, polar solvents are considered solvents for PET that are fundamentally unsuitable for or unable to dissolve PET, such as glyceryl triacetate, dimethyl succinate, or ethyl levulinate. Therefore, even with these disclosures, it remains impossible to predict which solvents are precisely suitable for dissolving PET. Furthermore, considering the reuse / recycling of the obtained PET, degradation of PET during the dissolution / precipitation step must be considered harmful; however, the prior art discloses many solvents that, even if some dissolution occurs, are unsuitable for recycling undegraded PET, meaning that even if a polymer material is reacquired, it is degraded, for example, due to reduced polymer chain length, reduced molecular weight, etc.

[0004] Although all these recycling attempts outlined above are known, it remains impossible to obtain textile fibers, for example, from such polymer blends that are comparable in textile properties to those made from virgin polyester (i.e., polyester newly produced from the corresponding monomers via chemical synthesis).

[0005] Therefore, the technical problem behind this invention is to provide a method for recovering polyester from polymer materials that overcomes these disadvantages, and in particular, enables the production of fibers with properties similar to those made from virgin polyester.

[0006] In a first aspect, the present invention relates to a method for preparing polyester fibers, the method comprising:

[0007] Provides a polymer blend comprising

[0008] (i) Polyester, and

[0009] (ii) One or more components selected from the group consisting of a second polymer, a third polymer, a colorant and a filler, wherein the second polymer and the third polymer are different from each other and different from the polyester of (i);

[0010] The method includes:

[0011] (a) Provide polymer blends and solvent systems;

[0012] (b) Optionally, the polymer blend is contacted with a solvent system at a temperature T1 of < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof, and a residue of a polymer blend depleted of second polymer and / or colorant and optionally filler or a portion thereof and comprising polyester, optionally third polymer and optionally filler or a portion thereof;

[0013] (c) Contact the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) with a solvent system at a temperature T2 > 170°C to obtain a solvent system rich in dissolved polyester and optionally containing filler or a portion of filler compared to the solvent system provided in (a), and a residue of the polymer blend, which is polyester-poor and optionally contains a third polymer and optionally contains filler or a portion of filler;

[0014] (d) Precipitate polyester from the solvent system rich in dissolved polyester obtained in (c) to obtain a solvent system containing precipitated polyester and dissolved polyester and optionally a filler or a portion thereof.

[0015] (e) Fibers are prepared from the precipitated polyester obtained in (d).

[0016] Surprisingly, the method of the present invention allows for the dissolution and precipitation of polyester without negatively impacting the recovered polyester. Specifically, not only can the decrease in the mass-average molecular weight (Mw) of the polyester recovered from the polymer blend be stopped, but an increase in the number-average molecular weight (Mn) can also be achieved. Furthermore, the recovered polyester can be directly reused in fiber production, wherein the resulting fibers are comparable, for example, to fibers obtained from virgin polyester materials in terms of their elastic limit and Young's modulus in the oriented state. Therefore, further processing of the polyester in a preferably closed-loop recycling method becomes possible. Preferably, polymeric materials preferably derived from textiles, fibers, and / or packaging are thus recycled therein. Of course, the recovered polyester can also be used for any further purpose without limitation. Moreover, the method of the present invention allows for the precipitation of polyester with minimal or no addition of an anti-solvent, which is advantageous in terms of solvent recycling.

[0017] In optional step (b) and step (c), “contact” preferably means immersing at least partially the polymer blend provided in (a) or the residue of the polymer blend optionally obtained in (b) in the solvent system. Preferably, immersing at least partially the polymer blend provided in (a) or the residue of the polymer blend optionally obtained in (b) in the solvent system means that at least 60%, more preferably at least 70%, more preferably at least 80%, more preferably at least 90%, more preferably at least 95%, more preferably at least 99% of the surface of the polymer blend provided in (a) or the surface of the residue of the polymer blend optionally obtained in (b) is in contact with the solvent system. Regarding the optional step (b), "rich in the second polymer" means that based on 100% by weight of the second polymer (if present) contained in the material provided in (a), at least 50% by weight, 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, and more preferably the second polymer (if present) contained in the material provided in (a) is dissolved in the solvent system. Regarding the residue obtained (optionally) in (b), "depleted in the second polymer" means that based on 100% by weight of the second polymer (if present) contained in the material provided in (a), ≤ 50% by weight, preferably ≤ 40% by weight, more preferably ≤ 30% by weight, more preferably ≤ 20% by weight, more preferably ≤ 10% by weight, and more preferably ≤ 5% by weight, the second polymer (if present) contained in the material provided in (a) is still present in the residue. Regarding the optional step (b), "rich in colorant" means that at least 50% by weight of the colorant (if present) contained in the polyester of the material provided in (a) is dissolved in the solvent system, based on 100% by weight of the colorant contained in the polyester of the material provided in (a). 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, and more preferably at least 95% by weight of the colorant (if present) contained in the polyester of the material provided in (a).Regarding the residue obtained in (b) (optionally), "depleted of the colorant" means that, based on 100% by weight of the colorant (if present) contained in the polyester of the material provided in (a), ≤ 50% by weight, preferably ≤ 40% by weight, more preferably ≤ 30% by weight, more preferably ≤ 20% by weight, more preferably ≤ 10% by weight, and more preferably ≤ 5% by weight of the colorant (if present) contained in the polyester of the material provided in (a) still remain in the residue. This means that the colorant contained in the polyester (i) is relatively easy to remove in step (c), i.e., dissolves in the solvent system along with the polyester in step (c), while the colorant contained in the third polymer (if present) is not easily dissolved, but is largely retained in the third polymer, and therefore also in the residue containing the third polymer. Regarding step (c), “a solvent system rich in dissolved polyester compared to the solvent provided in (a)” means that based on 100% by weight of the polyester contained in the material provided in (a), at least 50% by weight, 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, and more preferably at least 95% by weight of the polyester contained in the material provided in (a) is dissolved in the solvent system. Regarding the residue of the optionally obtained polymer blend in step (c), “depleted polyester and optionally containing a third polymer” means that based on 100% by weight of the polyester contained in the material provided in (a), ≤ 50% by weight, preferably ≤ 40% by weight, more preferably ≤ 30% by weight, more preferably ≤ 20% by weight, more preferably ≤ 10% by weight, more preferably ≤ 5% by weight of the polyester contained in the material provided in (a) still exists in the residue, wherein based on 100% by weight of the third polymer contained in the material provided in (a) (if present), at least 50% by weight, 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 of the third polymer contained in the material provided in (a) (if present) still exists in the residue. Regarding step (d), “solvent system of lean dissolved polyester” means that at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, and more preferably at least 90% by weight of the polyester contained in the solvent obtained in (c) are precipitated and no longer dissolved in the solvent.Regarding the solvent system obtained in step (b), the statement "optionally rich in filler or a portion of filler" and regarding the residue obtained in (b), the statement "optionally lean in filler or a portion of filler" means that if the polymer blend provided in (a) contains filler (which is soluble in the solvent system at temperature T1), then the soluble filler is also dissolved in the solvent system obtained in (b), and therefore the residue is lean in the soluble filler. If the polymer blend provided in (a) contains not only filler soluble at T1, but also filler insoluble in the solvent system at temperature T1, the insoluble filler remains in the residue of the polymer blend obtained in (b). If the insoluble filler is then soluble in the solvent system at T2, then the insoluble filler is then dissolved in the solvent system at T2, and therefore the solvent system obtained in (c) is rich in the filler, and the residue obtained in (c) is lean in the filler. In the case where the polymer blend provided in (a) contains only one or more fillers that are soluble in the solvent system at temperature T1, no filler is retained in the residue of the polymer blend obtained in (b), and therefore, the residue obtained in (c) also does not contain one or more fillers. In the case where the polymer blend provided in (a) contains only one or more fillers that are insoluble in the solvent system at temperature T2, all of the one or more fillers are retained in the residue of the polymer blend obtained in (b), but are therefore completely dissolved in the solvent system at T2, and therefore the residue obtained in (c) does not contain fillers. In the case where the polymer blend provided in (a) contains one or more fillers that are insoluble in the solvent system at temperature T1 and one or more fillers that are insoluble in the solvent system at temperature T2, these insoluble fillers are retained in the residue obtained in (c).

[0018] (d) Precipitation-cooling

[0019] In some embodiments of the method, precipitation in (d) includes cooling the solvent obtained in (c) which is richer in dissolved polyester than the solvent provided in (a) from T2 to a temperature below 140°C, wherein the cooling is carried out such that the temperature of the solvent system rich in dissolved polyester is maintained in the temperature range of 160°C to 145°C for a period of time of at least 5 minutes, preferably at least 10 minutes, more preferably in the range of 5 to 120 minutes, more preferably in the range of 10 to 100 minutes, and more preferably in the range of 15 to 100 minutes.

[0020] In some embodiments of the method, cooling is performed in (d) such that the solvent system rich in dissolved polyester has a viscosity in the range of 1 to 12 Pa s, more preferably in the range of 1 to 10 Pa s, as determined according to ASTM D445, in the temperature range of 160°C to 145°C.

[0021] In some embodiments of the method, cooling is performed at a cooling rate of ≤ 3.0°C / min, more preferably ≤ 1.5°C / min, more preferably in the range of 0.05 to 3.0°C / min, more preferably in the range of 0.13 to 3.0°C / min, more preferably in the range of 0.15 to 1.5°C / min, and more preferably in the range of 0.15 to 1.0°C / min.

[0022] In some embodiments of the method, the cooling of the solvent system in (d) is carried out from T2 to a temperature below 100°C.

[0023] In some embodiments of the method, the cooling of the solvent system in (d) is performed at a cooling rate of ≤ 3.0°C / min, preferably ≤ 1.5°C / min, more preferably in the range of 0.05 to 3.0°C / min, more preferably in the range of 0.13 to 3.0°C / min, more preferably in the range of 0.15 to 1.5°C / min, and more preferably in the range of 0.15 to 1.0°C / min from T2 to a temperature below 100°C.

[0024] In some embodiments of the method, the cooling of the solvent system in step (d) is performed without the addition of an antisolvent. An "antisolvent" is a solvent having a solubility of < 1 g / kg of polyester at temperatures ranging from 20°C to 25°C. In some embodiments, only a small amount of one or more antisolvents is added to and / or present in the solvent system in step (d), where a small amount means less than 5% by weight, preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, and more preferably less than 1% by weight of one or more antisolvents based on a total weight of 100% of the solvent system containing one or more antisolvents.

[0025] Fiber preparation in (e)

[0026] In some embodiments of the method, (e) includes:

[0027] (e.1) Optionally, the precipitated polyester obtained in (d) is melt-extruded to obtain an extrusion containing polyester;

[0028] (e.2) Optionally, the extrudate obtained in (e.1) is granulated to obtain an extruded product comprising polyester in granular form;

[0029] (e.3) The precipitated polyester obtained in (d) or the extruded product containing polyester in granular form obtained in (e.2) is used to prepare polyester fibers.

[0030] Optional step (e.1) may include applying a vacuum during melt extrusion, wherein the pressure is preferably in the range of 1 to 1013 mbar, more preferably in the range of 5 to 100 mbar. The vacuum is maintained for a period of time in the range of 1 to 30 minutes. The vacuum application removes residual water and causes polymerization, which in turn leads to an increase in intrinsic viscosity.

[0031] In some embodiments of the method, the melt extrusion in step (e.1) is carried out at a temperature of ≥ 250°C, more preferably in the range of 250°C to 300°C.

[0032] In some embodiments of the method, the extruded product containing polyester in granular form obtained in (e.2) is dried, optionally under vacuum, at a temperature in the range of 60°C to 160°C.

[0033] In some embodiments of the method, the fiber preparation in (e.3) is carried out by a method selected from the group consisting of melt spinning, electrospinning, wet spinning, matrix spinning, and combinations of two or more of these methods, preferably by melt spinning.

[0034] In some embodiments of this method, fiber preparation (e.3) by melt spinning includes

[0035] (e.3.1) Provide the precipitated polyester obtained in (d) or the polyester in granular form obtained in (e.2);

[0036] (e.3.2) The polyester provided in (e.3.1) is melted at a temperature in the range of 250°C to 300°C—preferably in an extruder, thereby obtaining molten polyester;

[0037] (e.3.3) Optionally, the molten polyester is filtered to obtain filtered molten polyester;

[0038] (e.3.4) Extruding the molten polyester of (e.3.2) or the filtered molten polyester obtained in (e.3.3) – preferably through a spinneret – to obtain at least one fiber filament.

[0039] In some embodiments of this method, fiber preparation includes...

[0040] (e.3.5) Optionally, two or more fiber filaments obtained in (e.3.4) may be combined to obtain fibers;

[0041] (e.3.6) At least one fiber filament obtained in (e.3.4) or the fiber obtained in (e.3.5) is collected on a strip, which preferably has a strip speed of at least 500 m / min, more preferably in the range of 1000 to 3000 m / min.

[0042] Filament is a continuous and flexible thread used in textile production.

[0043] A fiber is a long, thin aggregate of polymer molecules oriented primarily in one spatial direction. Fibers can be monofilaments or composed of multifilaments. Fibers have very different lengths, but for all fibers, the length is greater than the diameter.

[0044] The fibers obtained or available from (e), (e.3), (e.3.4), or (e.3.4), preferably from (e.3), (e.3.4), or (e.3.6), have an elastic limit in the oriented state greater than 15 cN / tex, preferably in the range of 15 to 70 cN / tex, as determined according to DIN 53816:1993-02. Furthermore, the Young's modulus of the fibers in the oriented state is determined according to DIN 53834-1:1976-02 to be in the range of 400 to 900 cN / tex.

[0045] intermediate steps

[0046] In some embodiments, if (b) is performed, the method includes, after (b) and before (c):

[0047] (v) Wash the residue of the polymer blend obtained in (b) with a washing solvent to obtain a washed residue that is depleted of the second polymer and / or colorant and optionally filler or a portion thereof, and contains polyester, optionally a third polymer and optionally filler or a portion thereof.

[0048] (w) Optionally, the residue obtained in (v) of the washing is dried.

[0049] The washing in optional step (v) is preferably performed using a solvent system having the characteristics (s.1), (s.2), and (s.3) as defined herein, and preferably using a solvent system containing one or more solvents from any of the groups defined herein. Preferably, the washing in optional step (v) is performed using the same solvent system used for (b). In some embodiments, the washing is performed using a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, or a mixture of two or more of these solvents. In some embodiments, the washing in optional step (v) is performed using a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, or a mixture of two or more of these solvents. The drying in optional step (w) is preferably 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°C to 210°C, preferably in the range of 60°C to 180°C, more preferably in the range of 80°C to 160°C; a drying time in the range of 30 minutes to 24 hours; and drying in an atmosphere containing nitrogen, preferably in an atmosphere having at least 90% by volume, more preferably 95% by volume, and more preferably at least 98% by volume. Drying is carried out by one or more methods selected from the group consisting of: contact drying, convection drying, and radiation drying. The contacting in step (c) is then performed based on the residue obtained in washing (and optionally drying) (b).

[0050] In some embodiments, the method includes (c) after and (d) before.

[0051] (x.1) Separating the solvent system obtained in (c) which is rich in dissolved polyester and optionally contains filler or a portion of filler from the residue of the polymer blend, wherein the separation is preferably carried out by heated filtration, more preferably by heated filtration at a temperature T3 (T3 = T2 ± 20°C) in the range of T2 minus 20°C to T2 plus 20°C, and more preferably at a temperature T3 (T3 = T2 ± 10°C) in the range of T2 minus 10°C to T2 plus 10°C, thereby obtaining the separated solvent system rich in dissolved polyester and optionally containing filler or a portion of filler;

[0052] (x.2) Optionally, the residue of the polymer blend obtained in (x.1) is contacted with a solvent system preferably at a temperature T3 as defined above in (x.1), followed by filtration, preferably heated filtration at a temperature T3 as defined above in (x.1), to obtain a residue of a polymer blend that is further lean on polyester and contains a third polymer and optionally a filler or a portion thereof; and a solvent system containing an additional amount of polyester and optionally containing a filler or a portion thereof;

[0053] (x.3) Optionally, the solvent system obtained in (x.2) containing an additional amount of polyester and optionally including filler or a portion of filler may be combined with the solvent system separated in (x.1) rich in dissolved polyester and optionally including filler or a portion of filler;

[0054] The precipitation in (d) is based on either the separated solvent system obtained in (x.1) or the combined solvent system obtained in (x.3).

[0055] In heated filtration, the solution, filter, and funnel are heated, preferably to a temperature T3 for each. Other means and methods for separation in (x.1) are known to those skilled in the art, such as non-heated filtration. In some embodiments, it is preferred that heated filtration be carried out at a pressure of ≥ 1 bar, more preferably in the range of 1 to 30 bar, more preferably in the range of 1 to 10 bar, and even more preferably in the range of 1 to 6 bar (heated pressure filtration). Preferably, the filter used in heated filtration is stable under the appropriate conditions and with respect to the appropriate solvent system, especially insoluble or non-degradable. For example, the filter may be made of polyetheretherketone (PEEK).

[0056] Preferably, the contact in (x.2) is performed such that, particularly in the case of heated filtration in (x.1), the residue of the polymer blend obtained in (x.1) remains on the filter and is contacted therewith with the solvent system, wherein the solvent system obtained in (x.2), containing a residual amount of polyester and optionally containing filler or a portion of filler, is separated therefrom due to filtration. In some embodiments, the solvent system obtained in (x.2), containing a residual amount of polyester and optionally containing filler or a portion of filler, is combined with the solvent system obtained in (x.1), which is rich in dissolved polyester and optionally contains filler or a portion of filler.

[0057] In some embodiments, the method follows (d) and

[0058] Included before (e)

[0059] (y.1) Separate the precipitated polyester obtained in (d) from the solvent system containing a lean-dissolved polyester and optionally a filler or a portion thereof, thereby obtaining the precipitated polyester and the solvent system containing a lean-dissolved polyester and optionally a filler or a portion thereof.

[0060] (y.2) Optionally wash the precipitated polyester obtained in (y.1);

[0061] (y.3) Dry the precipitated polyester obtained in (y.1) or the washed precipitated polyester obtained in (y.2) to obtain a dried (washed) precipitated polyester.

[0062] The separation in (y.1) is carried out by methods and means known to those skilled in the art, especially solid-liquid separation methods such as filtration, for example, heated pressure filtration, sedimentation, or centrifugation (see Handbuch der mechanischen Fest-Flüssig-Trennung Taschenbuch [Handbook of Mechanical Solid-Liquid Separation] – April 29, 2004 by Klaus Luckert (editor)). The washing in step (y.1) is preferably carried out with a solvent system having the characteristics (s.1), (s.2), and (s.3) as defined herein, and preferably with a solvent system containing one or more solvents from any of the groups defined above. In some embodiments, subsequent washing of the washing residue is performed with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, or a mixture of two or more of these solvents, or with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, or a mixture of two or more of these solvents. In some embodiments, the washing in optional step (y.2) is preferably performed with a solvent system having the characteristics (s.1), (s.2), and (s.3) as defined herein, and preferably with a solvent system containing one or more solvents from any group defined herein. In some embodiments, subsequent washing of the washing residue is performed with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, or a mixture of two or more of these solvents, or with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, or a mixture of two or more of these solvents. The drying in step (y.3) is preferably 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°C to 210°C, preferably in the range of 60°C to 180°C, more preferably in the range of 80°C to 160°C; a drying time in the range of 30 minutes to 24 hours; and drying in an atmosphere containing nitrogen, preferably in an atmosphere having at least 90% by volume, more preferably 95% by volume, and even more preferably at least 98% by volume. The drying is carried out by one or more methods selected from the group consisting of: contact drying, convection drying, and radiation drying.

[0063] In some embodiments, the method includes

[0064] (y.4) Granulate the dried (washed) precipitated polyester obtained in (y.3) to obtain granulated polyester.

[0065] "Granulation" is the process of compressing or molding material into a granular shape. Granulation can be performed as is known in the art, for example, by extrusion followed by underwater granulation or by strand granulation.

[0066] In some embodiments, the method includes (d) after and before (e), preferably after (y.3) or after (y.4) and before (e).

[0067] (z) Increase the intrinsic viscosity of the precipitated polyester obtained in (d) or the dried (washed) precipitated polyester obtained in (y.3) or the granulated polyester obtained in (y.4).

[0068] The increase in intrinsic viscosity according to (z) is carried out in the solid state and / or in which at least a portion of the precipitated polyester is in a molten state, wherein the increase in intrinsic viscosity makes it possible to increase the molecular weight of the polyester.

[0069] In some embodiments of the method, the increase in intrinsic viscosity in step (z) is performed at a temperature in the range of 180°C to 230°C, preferably in the range of 200°C to 230°C, and / or, preferably and in the range of 0.1 to 1013 mbar, preferably in the range of 5 to 1013 mbar, and / or, preferably and in the range of 1 to 80 hours, preferably in the range of 2 to 40 hours.

[0070] solvent system

[0071] In some embodiments of the method, the solvent system comprises one or more solvents, wherein

[0072] (s.1) The solvent system has the following Hansen solubility parameters.

[0073] -Energy from the dispersion forces between molecules (δD) ss ),

[0074] -Energy from the dipole intermolecular forces between molecules (δP) ss ),as well as

[0075] -Energy from hydrogen bonds between molecules (δH) ss ),

[0076] It satisfies equation 1

[0077] (8.8)² ≥ 4(δD ss -20)² + (δP ss -11.8)² + (δH ss -4.5)²

[0078] [Equation 1];

[0079] (s.2) Each solvent in the solvent system has a boiling point of at least 160°C at 1013 hPa; and

[0080] (s.3) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), carboxyl (COOH) and mercapto (SH).

[0081] The boiling point of a solvent should be understood as its boiling point under the corresponding pressure. 4(δD) ss -20)² + (δP ss -11.8)²+ (δH ss -4.5)² is greater than (8.8) 2 (i.e., 77.44) No solvent system is suitable for properly dissolving polyester, and 4(δD) ss -20)² + (δP ss -11.8)² + (δH ss -4.5)² is equal to or less than (8.8) 2 Any solvent system (i.e., 77.44) is suitable for dissolving polyesters. In the case where two or more solvents are part of the solvent system, i.e., n solvents, where n is an integer, n ≥ 2 and i = 1…n, the resulting mixture is calculated with respect to δD. ss δH ss and δP ss The Hansen solubility parameter for each of the n solvents (the percentage of each solvent in the solvent system is known) is taken as δD for each S(i) from the n solvents. si δH si and δP si The weighted arithmetic mean. Hansen parameters for the solvent are available in BIOVIA COSMOquick 2022.

[0082] Considering the three-dimensional form given by Equation 1 in three-dimensional Hansen space, it forms a structure centered at δD. c = 20, δP c = 11.8 and δH c = 4.5 and a sphere with radius r of 8.8. According to Charles Hansen, the dispersion parameter value needs to be doubled to achieve the spherical form. Since negative values ​​for δH are impossible, the Hansen sphere can also be considered as a dome, i.e., a hemisphere. PET has Hansen parameters according to version 5.1.03 (2008) of the Hansen solubility parameter (HSPiP) in practice, which are located inside the sphere but not at its center.

[0083] In some embodiments of the method, 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 solvent system consists of a solvent system that satisfies Equation 1, wherein when the solvent system consists of only one solvent system, the temperature T is a temperature at least 7 K lower than the boiling temperature of said solvent.

[0084] In some embodiments of the method, a solvent system comprising at least 90 wt%, more preferably at least 95 wt%, more preferably at least 98 wt%, and more preferably at least 99 wt% consists of two or more solvents, wherein the corresponding mixture satisfies Equation 1.

[0085] In some embodiments of this method, one or more solvents are selected from the group consisting of: N,N-dimethylbenzamide, N,N-dimethylphenylacetamide, 1,4-benzoquinone, acetophenone, dimethyl terephthalate, 1,3,5-trimethoxybenzene, 2-phenylacetophenone, N-methylcaprolactam, methyl benzoate, methyl-4-methoxybenzoate, butylene carbonate, N-ethylpyrrolidone, benzophenone, dibenzyl malonate, N... 2-Ethyl-caprolactam, methyl 2-(5-oxotetrahydrofuran-3-yl)acetate (FAME), methyl 2-(5-oxotetrahydrofuran-2-yl)acetate, phenylacetone, N-methoxypropyl-pyrrolidone, 1,4-cyclohexanedione, cyclohexane carbonate, N-methoxyethyl-pyrrolidone, N,N-diethylphenylacetamide, phenyl acetate, 1-(2-hydroxyethyl)pyrrolidone-2-one acetate (HEPAc) N,N-Diethylbenzamide, Isopropyl benzoate, Cyclohexylphenyl ketone, Ethyl phenylacetate, Phenylacetate, N-Methylmorpholine, Benzyl propionate, Benzyl acetate, Neopentyl glycol dibenzoate, Tetrahydrofurfuryl acetate, N-Methylimidazolium, Benzyl butyrate, 2-Pyrrolidone, 2-Phenoxyethanol propionate, 2-Phenoxyethyl isobutyrate, N,N-Dipropylbenzamide, N,N-Dimethyl Acetamide, N,N-diethylacetamide, dihydro-L-glucanone (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerol (GVL), δ-valerol, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyroxyvalerate (Rhodiasolv Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, N,N-dimethyllacticamide (AgniqueAMD 3L), 1,3-dimethyl-2-imidazolium ketone (DMI), and dimethyl sulfoxide (DMSO). In some embodiments of this method, one or more solvents are selected from the group consisting of: dihydro-L-glucosidone (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerol (GVL), δ-valerol, γ-butyrolactone, dimethyl sulfoxide, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and dimethyl sulfoxide (DMSO).In some embodiments of the method, one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, ethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and GVL. In some embodiments of the method, one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxovalerate (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, and propyl benzoate. In some embodiments of the method, one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxovalerate (Rhodiasolv® Polarclean), phenethyl acetate, and GVL. In some embodiments of the method, one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopyrrolidone (Rhodiasolv®Polarclean), and phenethyl acetate.

[0086] In some embodiments of this method, ethyl benzoate and butyl benzoate are not included as solvents.

[0087] In some embodiments of the method

[0088] (s.3a) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), secondary amine (-NH-), carboxyl (COOH) and mercapto (SH).

[0089] In some embodiments of the method, the solvent system comprises γ-valerolactone, wherein the solvent system comprises γ-valerolactone in a total weight percentage of 100 wt%, more preferably at least 50 wt%, more 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%, and more preferably at least 99 wt%.

[0090] In some embodiments of the method, the same solvent system as in (c) is used in optional step (b).

[0091] Polyester

[0092] In some embodiments of the method, the polyester is based on 1,2-ethylene glycol, more preferably according to (i) the polyester is based on 1,2-ethylene glycol and terephthalic acid (polyethylene terephthalate, PET), wherein the total weight of the polyester is 100% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, and more preferably at least 99% by weight of PET.

[0093] Colorant

[0094] In some embodiments of the method, the colorant is selected from the group consisting of dyes and optical brighteners, and mixtures of dyes and optical brighteners.

[0095] "Colorant" is a substance that causes a change in the color impression of a material. This includes dyes and optical brighteners that absorb the visible light wavelength range (400 to 780 nm), amplifying the material's light emission through UV light absorption and visible light emission (through fluorescence). Specifically, optical brighteners convert radiation invisible to the human eye (< 400 nm) into visible fluorescent radiation in the blue-red spectral range (400 to 600 nm). Colorants that can be used or are used to alter the color impression of polymeric materials are known to those skilled in the art. In the context of this invention, the term "dye" means any kind of dye such as dye, pigment, dispersion, wherein the dye is, for example, one or more selected from the group consisting of: acid dyes, basic dyes, direct dyes, disperse dyes, azo dyes, food dyes, solvent dyes, organic dyes, organic pigments, sulfur dyes, mordant dyes, and vat dyes. The term "optical brightener" includes optical brighteners, fluorescent brighteners, and fluorescent whitening agents.

[0096] An overview of colorants used in polymer materials can be found, for example, in the following literature: "Dyes and Pigments" Metin Açikyildiz, Kübra Günes, Ahmet Gürses Springer [Springer Publishers], 2016 (ISBN: 10: 3319338900); "Industrial Organic Pigments" - Klaus Hunger, Thomas Heber, Martin U. Schmidt, Friedrich Reisinger, Stefan Wanne Wiley-VCH [Wiley-VCH Publishers], 4th edition, 2018 (ISBN: 978-3-527-32608-2); "Chemistry and Technology of Natural and Synthetic Dyes and Pigments" - Ashis Kumar Samanta, Nasser Awwad, IntechOpen Publishers, 2020 (ISBN: 9781789859980, 9781789859973, 9781839687587); Encyclopedia of Color, Dyes, Pigments - Volume 1, Gerhard Pfaff, de Gruyter, 2021 (ISBN: 311058588X); Heinrich Zollinger: Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments, 3rd ed. WILEY-VCH Verlag, Weinheim, 2003 (ISBN: 3-906390-23-3); Klaus Hunger (ed.): Industrial Dyes: Chemistry, Properties, Applications [Industrial Dyes: Chemistry, Properties, and Applications]WILEY-VCH Verlag, Weinheim, 2003 (ISBN: 3-662-01950-7); Hermann Rath: Lehrbuch der Textilchemie. einschl. der textilchemischen Technologie [Textbook of Textile Chemistry (including Textile Chemistry Technology)]. 2nd edition. Springer-Verlag, Berlin, Heidelberg, 1963 (ISBN: 978-3-662-00065-6); Wilfried Kratzert, Rasmus Peicherert: Farbstoffe [Dyes]. Quelle & Meyer, Heidelberg, 1981 (ISBN: 3-494-01021-8); Ullmann's Encyclopedia of Industrial Chemistry [Ulman Encyclopedia of Industrial Chemistry], Wiley-VCH, 2000, sections “dyes and pigments” and “dyes, general survey” (ISBN: 9783527303854).

[0097] Preferably, in step b), only one or more colorants that are not covalently bonded to the polyester are removed from the polymer blend and transferred to the solvent system.

[0098] Second polymer

[0099] In some embodiments of the method, the second polymer is selected from the group consisting of polyurethane (PU), polyethylene glycol (PEG), polytetrahydrofuran (pTHF), mixtures of these polymers and copolymers of these polymers, wherein the second polymer is more preferably PU or a copolymer of PU and PEG and / or pTHF, and more preferably spandex.

[0100] "Spandex" is preferably a copolymer of polyurethane and polyethylene glycol and / or polytetrahydrofuran, and more preferably a copolymer of polyurethane and polyethylene glycol or a copolymer of polyurethane and polytetrahydrofuran.

[0101] In some embodiments of the method, the third polymer is selected from polypropylene (PP), polyethylene (PE), polyamide (PA), natural polymers (such as cotton, viscose fiber, flax) and mixtures of two or more thereof.

[0102] PA preferably includes PA6 and PA66; however, in some embodiments, PA6 is excluded as a third polymer, i.e., when used as PA, the third polymer is PA66.

[0103] Sources of polymer blends

[0104] In some embodiments of the method, the polymer blend is a packaging article, more preferably a beverage or food package, more preferably a bottle, which is preferably shredded by mechanical means before (a).

[0105] In some embodiments of the method, the polymer blend is a textile product, more preferably a garment product, which is preferably shredded and / or cut by mechanical means prior to (a).

[0106] filler

[0107] In some embodiments of the method, the filler is selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidant, UV filter, emulsifier, fixative, detergent dispersant, and modifier.

[0108] In some embodiments of the method, the polyester comprises PET, preferably PET, and the filler is one or more selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier, preferably the filler is selected from one or more of the group consisting of: binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier.

[0109] In some embodiments, the article provided in (a) comprises titanium dioxide (TiO2). In these preferred embodiments, the TiO2 is either absent from the precipitated polyester obtained in (d) or present in the precipitated polyester obtained in (d) in an amount ranging from 0.001 to 1.0 wt% based on a total precipitated polyester obtained in (d) of 100 wt%. In these preferred embodiments, the TiO2 (if present) is also present in the fibers prepared in (e).

[0110] Process conditions

[0111] In some embodiments of the method, T1 is a temperature in the range of 110°C to < 170°C, more preferably in the range of 110°C to 165°C, more preferably in the range of 110°C to 160°C, more preferably in the range of 120°C to 150°C, and more preferably in the range of 151°C to 160°C.

[0112] In some embodiments of the method, T2 is a temperature in the range of >170°C to 200°C, more preferably in the range of 175°C to 190°C, and even more preferably in the range of 180°C to 190°C.

[0113] Advantageously, energy saving is achieved by using solvent systems containing GVL, since operation is possible at temperatures ≤ 200°C.

[0114] In some embodiments of the method, (a), (b), (c), and (d) are performed at pressures in the range of 800 to 200,000 hPa.

[0115] In some embodiments of the method, the contact in (b) lasts for a period of at least 5 minutes, more preferably from 5 minutes to 10 hours, more preferably from 5 minutes to 5 hours, and more preferably from 5 minutes to 4 hours.

[0116] In some embodiments of the method, the contact in (c) lasts for a period of at least 0.1 hours, more preferably from 1 minute to 10 hours, more preferably from 1 minute to 2 hours, and more preferably from 5 minutes to 1 hour.

[0117] In some embodiments of the method, the contact in (b) and / or (c) is carried out in a mass-based ratio solvent system in the range of 1:1 to 100:1, more preferably in the range of 1:1 to 20:1: the polymer blend provided in (a) or the residue obtained in (b).

[0118] In some embodiments of the method, at least steps (b) and (c), more preferably all steps, are carried out in an inert atmosphere, preferably in the presence of an inert gas, wherein the inert gas is preferably selected from the group consisting of argon, helium, neon, nitrogen, and mixtures of two or more of these inert gases, preferably containing at least nitrogen, and more preferably nitrogen.

[0119] In some embodiments of the method, at least steps (b) and (c), more preferably all steps, are performed in batches or sequentially.

[0120] Part 2 - Polyester Fiber

[0121] The second aspect of the invention relates to a polyester fiber that is obtained or can be obtained by the method of the first aspect. All details, embodiments, and preferred embodiments disclosed in the sections relating to the first aspect also apply to the second aspect.

[0122] In some embodiments, the polyester fiber has an elastic limit in the oriented state of greater than 15 cN / tex, more preferably in the range of 15 to 70 cN / tex, as determined according to DIN 53816:1993-02.

[0123] In some embodiments, the polyester fiber has a Young's modulus in the oriented state in the range of 400 to 900 cN / tex, as determined according to DIN 53834-1:1976-02.

[0124] Part 3 - Uses of Polyester Fiber

[0125] The third aspect of the invention relates to the use of polyester fibers according to the second aspect in the preparation of textiles. All details, examples, and preferred embodiments disclosed in the sections relating to the first and second aspects also apply to the third aspect.

[0126] Aspect 4 - Methods for preparing textiles

[0127] A fourth aspect of the present invention relates to a method for preparing a product, the method comprising:

[0128] (I) Providing the polyester of the second aspect;

[0129] (II) Textiles are prepared from the polyester provided in (I).

[0130] All details, embodiments, and preferred embodiments disclosed in the sections relating to the first through third aspects also apply to the fourth aspect.

[0131] Fifth aspect - Methods related to the second polymer

[0132] The fifth aspect of the invention relates to a method of the first aspect, wherein (b) comprises:

[0133] (b.1) Contacting the polymer blend with a solvent system at a temperature T1 < 170°C to obtain a solvent system optionally rich in a colorant, optionally rich in a second polymer and optionally containing a filler or a portion thereof, and a residue of a polymer blend depleted of the optional colorant and the optional second polymer and containing a polyester, optionally a third polymer and optionally a filler or a portion thereof;

[0134] (b.2) Separating the solvent system obtained in (b.1), which is optionally rich in colorant, optionally rich in a second polymer, and optionally contains filler or a portion of filler, from the residue—preferably by a physical separation method, thereby obtaining a separated solvent system that is optionally rich in colorant and optionally rich in a second polymer and optionally contains filler or a portion of filler compared to the solvent system provided in (a); and

[0135] (b.3) Separate an optional second polymer from the solvent system to obtain a separated fraction containing the second polymer.

[0136] All details, embodiments, and preferred embodiments disclosed in the sections relating to the first through fourth aspects also apply to the fifth aspect.

[0137] In some embodiments, the method includes additional steps:

[0138] - The residue that is obtainable or acquireable according to the method of the first aspect, preferably obtainable or acquireable from step (d), more preferably by conversion of a residue that is obtainable or acquireable according to the method of the first aspect, preferably obtainable or acquireable from step (d) containing at least a third polymer,

[0139] To obtain one or more monomers, polymers, or polymer products.

[0140] In some embodiments of the method, the monomer is a diol or polyol, preferably butanediol; an aldehyde, preferably formaldehyde; a diisocyanate or polyisocyanate, preferably methylene diphenyl diisocyanate (MDI), polymeric methylene diphenyl diisocyanate (pMDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI); an amide, preferably caprolactam; an olefin, preferably styrene, ethylene and norbornene; an alkyne; a (di) ester, preferably methyl methacrylate; a monoacid or diacid, preferably adipic acid or terephthalic acid; a diamine, preferably hexamethylenediamine or nonadiamine; or a sulfone, preferably 4,4'-dichlorodiphenyl sulfone.

[0141] In some embodiments of this method, the polymer is and / or the polymer product comprises polyamide (PA), preferably PA 6 or PA 66; a polyisocyanate addition polymer, preferably polyurethane (PU), thermoplastic polyurethane (TPU), polyurea or polyisocyanurate (PIR); low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrene (PS), polyacrylonitrile butadiene styrene (ABS), polystyrene acrylonitrile (SAN), polyacrylate styrene acrylonitrile polyacrylate (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene) -Isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate (PBAT), polyester (PES), polyethersulfone (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulfone (PSU), polyphenylene sulfone (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene ether) (PPO), poly(p-phenylene ether) (PPE); or copolymers or mixtures thereof.

[0142] In some embodiments of the method, the polymer and / or polymer product is one or more of the following:

[0143] - Automotive parts; preferably cylinder head covers, engine hoods, turbocharger housings, turbocharger baffles, intake pipes, intake manifolds, connectors, gears, fan wheels, coolant tanks, housings, heat exchanger housings, coolant coolers, turbocharger coolers, thermostats, water pumps, radiators, fasteners, battery system components for electric vehicles, dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C, or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper protective housings, decorative grilles, covers, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushioning pads or coatings;

[0144] - Fabric; preferably shirts, trousers, sweaters, boots, shoes, shoe soles, bodysuits or jackets;

[0145] - Electrical components; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foil, wire, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, spools, lamps, diodes, LEDs, transistors, connectors, voltage regulators, integrated circuits (ICs), processors, controllers, memory, sensors, microswitches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, gaskets, bolts, strips, slide-in guides, screws, nuts, membrane hinges, spring hooks (clamp-in) or spring tongues;

[0146] - Consumer goods, agricultural products, or pharmaceutical products; preferably tennis strings, climbing ropes, bristles, brushes, artificial turf, 3D printed filaments, lawnmowers, zippers, hook and loop fasteners, paper machine netting, extrusion coatings, fishing lines, fishing nets, offshore lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyors, sliding bearings, rollers, wheels, gears, ring gears, screws and spring dampers, hoses, pipes, cable sheaths, sockets, switches, cable ties, fan wheels, carpets, cosmetic boxes or bottles, mattresses, cushioning pads, insulating materials, detergents, dishwasher detergent blocks or powders, shampoos, shower gels, bath gels, soaps, fertilizers, fungicides, or pest control agents;

[0147] - For packaging in the food industry, single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film, or laminated film are preferred; or

[0148] - Structural components, preferably rotor blades, insulating materials, frames, housings, walls, coatings, or partition walls.

[0149] In some embodiments of the method, the content of the third polymer in the monomer, polymer, and / or polymer product is 1 wt% or more, preferably 2 wt% or more, more preferably 5 wt% or more, more preferably 15 wt% or more, more preferably 30 wt% or more, more preferably 40 wt% or more, more preferably 60 wt% or more, more preferably 80 wt% or more, more preferably 90 wt% or more, more preferably 95 wt% or more; and / or

[0150] The content of the third polymer in the monomer, polymer and / or polymer product is 100% by weight or less, preferably 95% by weight or less, more preferably 90% by weight or less, more preferably 50% by weight or less, more preferably 25% by weight or less, more preferably 10% by weight or less; and preferably, this content is determined based on identity preservation and / or segregation and / or mass balance and / or book and claim chain of custody models, preferably based on mass balance, preferably according to the International Sustainability and Carbon Certification (ISCC) standard.

[0151] The invention is further illustrated by the following set of embodiments and combinations of embodiments derived from the dependent relationships and reverse references shown. In particular, it should be noted that in each instance of reference to a series of embodiments, such as in the context of the term "method as described in any one of Embodiments 1 to 4," each embodiment in this series is intended to clearly disclose to those skilled in the art that the wording of this term should be understood by those skilled in the art to be synonymous with "method as described in any one of Embodiments 1, 2, 3, and 4." Furthermore, it should be clearly noted that the following set of embodiments represents appropriate structural portions of the general description of preferred aspects of the invention and therefore appropriately supports, but does not represent, the claims of the invention.

[0152] 1. A method for preparing polyester fibers, the method comprising:

[0153] Provides a polymer blend comprising

[0154] (i) Polyester, and

[0155] (ii) One or more components selected from the group consisting of a second polymer, a third polymer, a colorant and a filler, wherein the second polymer and the third polymer are different from each other and different from the polyester of (i);

[0156] The method includes:

[0157] (a) Provide the polymer blend and the solvent system;

[0158] (b) Optionally, the polymer blend is contacted with the solvent system at a temperature T1 of < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally the filler or a portion thereof, and a residue of the polymer blend depleted in the second polymer and / or colorant and optionally the filler or a portion thereof and containing the polyester, optionally the third polymer and optionally the filler or a portion thereof;

[0159] (c) Contacting the polymer blend provided in (a) or the residue of the polymer blend obtained optionally in (b) with a solvent system at a temperature T2 > 170°C to obtain a solvent system rich in dissolved polyester and optionally containing the filler or a portion of the filler compared to the solvent system provided in (a), and optionally a residue of the polymer blend, the residue being polyester-poor and optionally containing the third polymer and optionally containing the filler or a portion of the filler;

[0160] (d) Precipitate the polyester from the solvent system rich in dissolved polyester obtained in (c), thereby obtaining a solvent system containing precipitated polyester and dissolved polyester and optionally the filler or a portion thereof;

[0161] (e) Fibers are prepared from the precipitated polyester obtained in (d).

[0162] 2. The method as described in Example 1, wherein precipitation in (d) comprises cooling the solvent obtained in (c) which is richer in dissolved polyester than the solvent provided in (a) from T2 to a temperature below 140°C, wherein the cooling is performed such that the temperature of the solvent system rich in dissolved polyester is maintained in the temperature range of 160°C to 145°C for a period of time of at least 5 minutes, preferably at least 10 minutes, more preferably in the range of 5 to 120 minutes, more preferably in the range of 10 to 100 minutes, and more preferably in the range of 15 to 100 minutes.

[0163] 3. The method as described in Example 2, wherein cooling is performed in (d) such that the solvent system rich in dissolved polyester has a viscosity in the range of 1 to 12 Pas, preferably in the range of 1 to 10 Pas, as determined according to ASTM D445, in the temperature range of 160°C to 145°C.

[0164] 4. The method as described in Example 2 or 3, wherein cooling is performed at a cooling rate of ≤ 3.0°C / min, preferably ≤ 1.5°C / min, more preferably in the range of 0.05 to 3.0°C / min, more preferably in the range of 0.13 to 3.0°C / min, more preferably in the range of 0.15 to 1.5°C / min, and even more preferably in the range of 0.15 to 1.0°C / min.

[0165] 5. The method as described in any one of Examples 2 to 4, wherein the cooling of the solvent system in (d) is performed from T2 to a temperature below 100°C.

[0166] 6. The method as described in any one of Examples 2 to 5, wherein the cooling of the solvent system in (d) is performed without the addition of an antisolvent.

[0167] 7. The method as described in any one of Examples 1 to 6, wherein (e) includes

[0168] (e.1) Optionally, the precipitated polyester obtained in (d) is melt-extruded to obtain an extrusion containing the polyester;

[0169] (e.2) Optionally, the extrudate obtained in (e.1) is granulated to obtain an extruded product comprising the polyester in granular form;

[0170] (e.3) The precipitated polyester obtained in (d) or the extruded product containing the polyester in granular form obtained in (e.2) is used to prepare polyester fibers.

[0171] 8. The method as described in any of Examples 7, wherein the melt extrusion in step (e.1) is carried out at a temperature of ≥ 250°C, preferably in the range of 250°C to 300°C.

[0172] 9. The method as described in any of Examples 7 or 8, wherein the extruded product comprising the polyester in granular form obtained in (e.2) is dried, optionally under vacuum, at a temperature in the range of 60°C to 160°C.

[0173] 10. The method of any one of Examples 7 to 9, wherein the fiber preparation of (e.3) is carried out by a method selected from the group consisting of melt spinning, electrospinning, wet spinning, matrix spinning, and combinations of two or more of these methods, preferably by melt spinning.

[0174] 11. The method as described in Example 10, wherein the fiber preparation (e.3) by melt spinning includes

[0175] (e.3.1) Provide the precipitated polyester obtained in (d) or the polyester obtained in (e.2) in granular form;

[0176] (e.3.2) The polyester provided in (e.3.1) is melted at a temperature in the range of 250°C to 300°C—preferably in an extruder—to obtain a molten polyester;

[0177] (e.3.3) Optionally, the molten polyester is filtered to obtain filtered molten polyester;

[0178] (e.3.4) The molten polyester of (e.3.2) or the filtered molten polyester obtained in (e.3.3) is extruded—preferably through a spinneret—to obtain at least one fiber filament.

[0179] 12. The method as described in Example 11, wherein the fiber preparation includes

[0180] (e.3.5) Optionally, two or more fiber filaments obtained in (e.3.4) may be combined to obtain fibers;

[0181] (e.3.6) The at least one fiber filament obtained in (e.3.4) or the fiber obtained in (e.3.5) is collected on a strip, which preferably has a strip speed of at least 500 m / min, more preferably in the range of 1000 to 3000 m / min.

[0182] 13. The method as described in any one of Examples 1 to 12, wherein if (b) is performed, the method comprises, after (b) and before (c):

[0183] (v) Wash the residue of the polymer blend obtained in (b) with a washing solvent to obtain a washed residue that is depleted of the second polymer and / or colorant and optionally the filler or a portion thereof, and contains the polyester, optionally the third polymer and optionally the filler or a portion thereof.

[0184] (w) Optionally, the residue obtained in (v) of the washing is dried.

[0185] 14. The method as described in any one of Examples 1 to 13, wherein the method includes (c) after and before (d).

[0186] (x.1) The solvent system obtained in (c) which is rich in dissolved polyester and optionally contains the filler or a portion thereof, is separated from the residue of the polymer blend, wherein the separation is preferably carried out by heated filtration, more preferably by heated filtration at a temperature T3 (T3 = T2 ± 20°C) in the range of T2 minus 20°C to T2 plus 20°C, and more preferably at a temperature T3 (T3 = T2 ± 10°C) in the range of T2 minus 10°C to T2 plus 10°C, thereby obtaining the separated solvent system rich in dissolved polyester and optionally containing the filler or a portion thereof;

[0187] (x.2) Optionally, the residue of the polymer blend obtained in (x.1) is contacted with a solvent system preferably at a temperature T3 as defined above in (x.1), followed by filtration, preferably heated filtration at a temperature T3 as defined above in (x.1), to obtain a residue of the polymer blend that is further lean on polyester and contains the third polymer and optionally the filler or a portion thereof; and a solvent system containing an additional amount of the polyester and optionally containing the filler or a portion thereof;

[0188] (x.3) Optionally, the solvent system obtained in (x.2) containing the additional amount of polyester and optionally including the filler or a portion of the filler is combined with the solvent system separated in (x.1) rich in dissolved polyester and optionally including the filler or a portion of the filler;

[0189] The precipitation in (d) is based on the separate solvent system obtained in (x.1) or the combined solvent system obtained in (x.3).

[0190] 15. The method as described in any one of Examples 1 to 14, wherein the method follows (d) and

[0191] Included before (e)

[0192] (y.1) Separate the precipitated polyester obtained in (d) from the solvent system containing a lean-dissolved polyester and optionally the filler or a portion thereof, thereby obtaining the precipitated polyester and the solvent system containing a lean-dissolved polyester and optionally the filler or a portion thereof;

[0193] (y.2) Optionally, the precipitated polyester obtained in (y.1) is washed;

[0194] (y.3) Dry the precipitated polyester obtained in (y.1) or the washed precipitated polyester obtained in (y.2) to obtain a dried (washed) precipitated polyester;

[0195] (y.4) Optionally, the dried (washed) precipitated polyester obtained in (y.3) is granulated to obtain granulated polyester.

[0196] 16. The method as described in any one of Examples 1 to 15, wherein the method includes (d) after and before (e), preferably after (y.3) or after (y.4) and before (e).

[0197] (z) Increase the intrinsic viscosity of the precipitated polyester obtained in (d) or the dried (washed) precipitated polyester obtained in (y.3) or the granulated polyester obtained in (y.4).

[0198] 17. The method as described in Example 16, wherein the increase in intrinsic viscosity in step (z) is performed at a temperature in the range of 180°C to 230°C, preferably in the range of 200°C to 230°C, and / or, preferably and in the range of 0.1 to 1013 mbar, preferably in the range of 5 to 1013 mbar, and / or, preferably and in the range of 1 to 80 hours, preferably in the range of 2 to 40 hours.

[0199] 18. The method as described in any one of Examples 1 to 17, wherein the solvent system comprises one or more solvents, wherein,

[0200] (s.1) This solvent system has the following Hansen solubility parameters.

[0201] -Energy from the dispersion forces between molecules (δD) ss ),

[0202] -Energy from the dipole intermolecular forces between molecules (δP) ss ),as well as

[0203] -Energy from hydrogen bonds between molecules (δH) ss ),

[0204] It satisfies equation 1

[0205] (8.8)² ≥ 4(δD ss -20)² + (δP ss -11.8)² + (δH ss -4.5)²

[0206] [Equation 1];

[0207] (s.2) Each solvent in the solvent system has a boiling point of at least 160°C at 1013 hPa; and

[0208] (s.3) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), carboxyl (COOH) and mercapto (SH).

[0209] 19. The method as described in any one of Examples 1 to 18, wherein at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, and even more preferably at least 99% by weight of the solvent system consists of a solvent system satisfying Equation 1, wherein when the solvent system consists of only one solvent system, the temperature T is at least 7 K lower than the boiling temperature of said solvent.

[0210] 20. The method as described in any one of Examples 1 to 19, wherein at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, and even more preferably at least 99% by weight, of the solvent system comprises two or more solvents, wherein the corresponding mixtures satisfy Equation 1.

[0211] 21. The method of any one of Examples 1 to 20, wherein the one or more solvents are selected from the group consisting of: N,N-dimethylbenzamide, N,N-dimethylphenylacetamide, 1,4-benzoquinone, acetophenone, dimethyl terephthalate, 1,3,5-trimethoxybenzene, 2-phenylacetophenone, N-methylcaprolactam, methyl benzoate, methyl-4-methoxybenzoate, butylene carbonate, N-ethylpyrrolidone, Benzophenone, dibenzyl malonate, N-ethylcaprolactam, methyl 2-(5-oxotetrahydrofuran-3-yl)acetate (FAME), methyl 2-(5-oxotetrahydrofuran-2-yl)acetate, acetone, N-methoxypropylpyrrolidone, 1,4-cyclohexanedione, cyclohexane carbonate, N-methoxyethylpyrrolidone, N,N-diethylphenylacetamide, phenyl acetate, 1-(2-hydroxyethyl)pyrrolidone-2 HEPAc (a type of ketone acetate), N,N-diethylbenzamide, isopropyl benzoate, cyclohexylphenyl ketone, ethyl phenyl acetate, phenyl acetate, N-methylmorpholine, benzyl propionate, benzyl acetate, neopentyl glycol dibenzoate, tetrahydrofurfuryl acetate, N-methylimidazolium, benzyl butyrate, 2-pyrrolidone, 2-phenoxyethanol propionate, 2-phenoxyethyl isobutyrate, N,N-dipropylbenzamide, N,N-dimethylethyl... Amides, N,N-diethylacetamide, dihydro-L-glucanone (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerolactone (GVL), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, N,N-dimethyllactic acid amide (Agnique AMD 3L), 1,3-dimethyl-2-imidazolium ketone (DMI), and dimethyl sulfoxide (DMSO).

[0212] 22. The method of any one of Examples 1 to 21, wherein the one or more solvents are selected from the group consisting of: dihydro-L-glucosidone (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerol (GVL), δ-valerol, γ-butyrolactone, dimethyl sulfoxide, methyl 5-(dimethylamino)-2-methyl-5-oxopyroxyvalerate (Rhodiasolv®Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and dimethyl sulfoxide (DMSO).

[0213] 23. The method of any one of Examples 1 to 22, wherein the one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, ethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and GVL.

[0214] 24. The method of any one of Examples 1 to 23, wherein the one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, ethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, and propyl benzoate.

[0215] 25. The method of any one of Examples 1 to 24, wherein one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopyrrolidone (Rhodiasolv®Polarclean), phenethyl acetate, and GVL.

[0216] 26. The method of any one of Examples 1 to 25, wherein the one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopyrrolidone (Rhodiasolv®Polarclean), and phenethyl acetate.

[0217] 27. The method as described in any one of Examples 1 to 26, wherein ethyl benzoate and butyl benzoate are excluded as solvents.

[0218] 28. The method as described in any one of Examples 1 to 27, wherein,

[0219] (s.3a) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), secondary amine (-NH-), carboxyl (COOH) and mercapto (SH).

[0220] 29. The method of any one of Examples 1 to 28, wherein the solvent system comprises γ-valerolactone, wherein the solvent system comprises γ-valerolactone based on a total weight of 100 wt% more preferably at least 50 wt%, more 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 99 wt%.

[0221] 30. The method as described in any one of Examples 1 to 29, wherein, in optional step (b), the same solvent system as in (c) is used.

[0222] 31. The method of any one of Examples 1 to 30, wherein the polyester is based on 1,2-ethylene glycol, more preferably according to (i) the polyester is based on 1,2-ethylene glycol and terephthalic acid (polyethylene terephthalate, PET), wherein the polyester is PET if the total weight of the polyester is 100% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, and more preferably at least 99% by weight.

[0223] 32. The method of any one of Examples 1 to 31, wherein the colorant is selected from the group consisting of dyes and optical brighteners and mixtures of dyes and optical brighteners.

[0224] 33. The method of any one of Examples 1 to 32, wherein the second polymer is selected from the group consisting of polyurethane (PU), polyethylene glycol (PEG), polytetrahydrofuran (pTHF), mixtures of these polymers and copolymers of these polymers, wherein the second polymer is more preferably PU or a copolymer of PU and PEG and / or pTHF, more preferably spandex.

[0225] 34. The method of any one of Examples 1 to 33, wherein the third polymer is selected from polypropylene (PP), polyethylene (PE), polyamide (PA), natural polymers (such as cotton, viscose fiber, flax) and mixtures of two or more thereof.

[0226] 35. The method of any one of Examples 1 to 34, wherein the polymer blend is a packaging article, preferably a beverage package or food package, more preferably a bottle, which is preferably mechanically shredded before (a).

[0227] 36. The method of any one of Examples 1 to 35, wherein the polymer blend is a textile article, preferably a garment article, which is preferably shredded by mechanical means before (a).

[0228] 37. The method of any one of Examples 1 to 36, wherein the filler is selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing agent / oil repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier.

[0229] 38. The method of Example 37, wherein the polyester comprises PET, preferably PET, and the filler is one or more selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier, preferably the filler is selected from one or more of the group consisting of: binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier.

[0230] 39. The method as described in any one of Examples 1 to 38, wherein T1 is a temperature in the range of 110°C to < 170°C, preferably in the range of 110°C to 165°C, more preferably in the range of 110°C to 160°C, more preferably in the range of 120°C to 150°C, and even more preferably in the range of 151°C to 160°C.

[0231] 40. The method as described in any one of Examples 1 to 39, wherein T2 is a temperature in the range of >170°C to 200°C, preferably in the range of 175°C to 190°C, and more preferably in the range of 180°C to 190°C.

[0232] 41. The method as described in any one of Examples 1 to 40, wherein (a), optionally (b), (c) and (d) are carried out at a pressure in the range of 800 to 200,000 hPa.

[0233] 42. The method as described in any one of Examples 1 to 41, wherein the contact in (b) is performed 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 5 hours, and even more preferably in the range of 5 minutes to 4 hours.

[0234] 43. The method as described in any one of Examples 1 to 42, wherein the contact in (c) is performed for a period of at least 0.1 hours, preferably in the range of 1 minute to 10 hours, more preferably in the range of 1 minute to 2 hours, and even more preferably in the range of 5 minutes to 1 hour.

[0235] 44. The method of any one of Examples 1 to 43, wherein the contact in (b) and / or (c) is carried out in a mass-based ratio solvent system in the range of 1:1 to 100:1, preferably in the range of 1:1 to 20:1: the polymer blend provided in (a) or the residue obtained in (b).

[0236] 45. The method as described in any one of Examples 1 to 44, wherein at least steps (b) and (c), preferably all steps, are carried out in an inert atmosphere, preferably in the presence of an inert gas, wherein the inert gas is preferably selected from the group consisting of argon, helium, neon, nitrogen, and mixtures of two or more of these inert gases, preferably containing at least nitrogen, more preferably nitrogen.

[0237] 46. ​​The method as described in any one of Examples 1 to 45, wherein at least steps (b) and (c), preferably all steps, are performed in batches or sequentially.

[0238] 47. A polyester fiber, which is obtained or can be obtained by the method described in any one of Examples 1 to 46.

[0239] 48. The polyester fiber as described in Example 47, having an elastic limit in the oriented state greater than 15 cN / tex, preferably in the range of 15 to 70 cN / tex, as determined according to DIN 53816:1993-02.

[0240] 49. The polyester fiber as described in Examples 47 or 48, having a Young's modulus in the oriented state in the range of 400 to 900 cN / tex as determined according to DIN 53834-1:1976-02.

[0241] 50. Use of polyester fibers as described in any one of Examples 47 to 49 for the preparation of textiles.

[0242] 51. A method for preparing a product, the method comprising:

[0243] (I) Provide a polyester as described in any one of Examples 47 to 49;

[0244] (II) Textiles are prepared from the polyester provided in (I).

[0245] 52. The method as described in any one of Examples 1 to 46, wherein (b) comprises:

[0246] (b.1) Contact the polymer blend with the solvent system at a temperature T1 < 170°C to obtain a solvent system optionally rich in colorant, optionally rich in second polymer and optionally containing the filler or a portion of the filler, and a residue of the polymer blend depleted of the optional colorant and optional second polymer and containing the polyester, optionally the third polymer and optionally the filler or a portion of the filler;

[0247] (b.2) Separating the solvent system obtained in (b.1), which is optionally rich in colorant, optionally rich in the second polymer, and optionally contains the filler or a portion of the filler, from the residue—preferably by a physical separation method, thereby obtaining a separated solvent system that is optionally rich in colorant, optionally rich in the second polymer, and optionally contains the filler or a portion of the filler compared to the solvent system provided in (a); and

[0248] (b.3) Separate the optional second polymer from the solvent system to obtain a separated fraction containing the second polymer.

[0249] 53. A method, preferably as described in any one of Examples 1 to 46 or 52, comprising the following additional steps:

[0250] - The residue that is obtainable or acquireable by any one of Examples 1 to 42 or 49, preferably obtainable or acquireable from step (d), more preferably obtainable or acquireable by any one of Examples 1 to 46 or 52, preferably obtainable or acquireable from step (d), comprising at least a third polymer, is converted.

[0251] To obtain one or more monomers, polymers, or polymer products.

[0252] 54. The method as described in Example 53,

[0253] The monomer is a diol or polyol, preferably butanediol; an aldehyde, preferably formaldehyde; a diisocyanate or polyisocyanate, preferably methylene diphenyl diisocyanate (MDI), polymeric methylene diphenyl diisocyanate (pMDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI); an amide, preferably caprolactam; an olefin, preferably styrene, ethylene and norbornene; an alkyne; a (di) ester, preferably methyl methacrylate; a monoacid or diacid, preferably adipic acid or terephthalic acid; a diamine, preferably hexamethylenediamine or nonadiamine; or a sulfone, preferably 4,4'-dichlorodiphenyl sulfone.

[0254] 55. The method as described in Examples 53 or 54,

[0255] The polymer and / or the polymer product contains polyamide (PA), preferably PA 6 or PA 66; a polyisocyanate addition polymer, preferably polyurethane (PU), thermoplastic polyurethane (TPU), polyurea or polyisocyanurate (PIR); low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrene (PS), polyacrylonitrile butadiene styrene (ABS), polystyrene acrylonitrile (SAN), polyacrylate styrene acrylonitrile (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene) -Isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate (PBAT), polyester (PES), polyethersulfone (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulfone (PSU), polyphenylene sulfone (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene ether) (PPO), poly(p-phenylene ether) (PPE); or copolymers or mixtures thereof.

[0256] 56. The method as described in any one of Examples 53 to 55,

[0257] The polymer and / or the polymer product is one or more of the following:

[0258] - Automotive parts; preferably cylinder head covers, engine hoods, turbocharger housings, turbocharger baffles, intake pipes, intake manifolds, connectors, gears, fan wheels, coolant tanks, housings, heat exchanger housings, coolant coolers, turbocharger coolers, thermostats, water pumps, radiators, fasteners, battery system components for electric vehicles, dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C, or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper protective housings, decorative grilles, covers, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushioning pads or coatings;

[0259] - Fabric; preferably shirts, trousers, sweaters, boots, shoes, shoe soles, bodysuits or jackets;

[0260] - Electrical components; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foil, wire, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, spools, lamps, diodes, LEDs, transistors, connectors, voltage regulators, integrated circuits (ICs), processors, controllers, memory, sensors, microswitches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, gaskets, bolts, strips, slide-in guides, screws, nuts, membrane hinges, spring hooks (clamp-in) or spring tongues;

[0261] - Consumer goods, agricultural products, or pharmaceutical products; preferably tennis strings, climbing ropes, bristles, brushes, artificial turf, 3D printed filaments, lawnmowers, zippers, hook and loop fasteners, paper machine netting, extrusion coatings, fishing lines, fishing nets, offshore lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyors, sliding bearings, rollers, wheels, gears, ring gears, screws and spring dampers, hoses, pipes, cable sheaths, sockets, switches, cable ties, fan wheels, carpets, cosmetic boxes or bottles, mattresses, cushioning pads, insulating materials, detergents, dishwasher detergent blocks or powders, shampoos, shower gels, bath gels, soaps, fertilizers, fungicides, or pest control agents;

[0262] - For packaging in the food industry, single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film, or laminated film are preferred; or

[0263] - Structural components, preferably rotor blades, insulating materials, frames, housings, walls, coatings, or partition walls.

[0264] 57. The method as described in any one of Examples 53 to 56,

[0265] Wherein, the content of the third polymer in the monomer, polymer and / or polymer product is 1% by weight or more, preferably 2% by weight or more, more preferably 5% by weight or more, more preferably 15% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 60% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more, more preferably 95% by weight or more; and / or

[0266] Wherein, the content of the third polymer in the monomer, polymer and / or polymer product is 100% by weight or less, preferably 95% by weight or less, more preferably 90% by weight or less, more preferably 50% by weight or less, more preferably 25% by weight or less, more preferably 10% by weight or less; and

[0267] Preferably, the content is determined based on an identity preservation and / or segregation and / or quality balance and / or ledger and declaration chain of custody model, preferably based on quality balance, preferred International Sustainability and Carbon Certification (ISCC) standards.

[0268] The invention is further illustrated by the following reference examples, comparative examples, and examples. Example

[0269] method

[0270] Viscosity determination: ASTM D445

[0271] Determination of elastic limit: DIN 53816:1993-02

[0272] Determination of Young's modulus: DIN 53834-1:1976-02

[0273] GPC (Gel Permeation Chromatography):

[0274] Sample preparation:

[0275] Dissolve approximately 6 mg of sample in 5 ml of eluent (hexafluoroisopropanol + 0.05 wt% potassium trifluoroacetate) overnight. Filter all sample solutions through a Millipore Millex FG (0.2 µm) filter before injection. Place the sealed sample vial into the autosampler.

[0276] Experimental conditions:

[0277] An Agilent 1100 HPLC system was used, consisting of an isocratic pump, vacuum degasser, autosampler, and column oven (35°C). This Agilent system also included differential refractive index (DRI) and variable ultraviolet (UVW) detectors. Routine SEC data acquisition and processing were performed by WinGPCUnichrom of PSS (Polymer Standards Service). A combination of an Agilent PL-HFIP guard column (7.5 × 50 mm) and two PL-HFIP gel columns (7.5 × 300 mm, 9 µm) were placed in series. Hexafluoroisopropanol + 0.05 wt% potassium trifluoroacetate was used as the eluent at a flow rate of 1 ml / min. 50 µl of each sample solution was injected. Calibration was obtained using PMMA standards (Polymer Standards Service) with a narrow molar mass distribution ranging from M = 800 to M = 2.200.000 g / mol or M = 600 to M = 2.050.000 g / mol. Molar masses outside this range were extrapolated.

[0278] chemicals

[0279]

[0280] PET with Hansen parameters of δD = 18.2, δP = 6.4 and δH = 6.6 according to Hansen solubility parameters in practice (HSPiP) version 5.1.03 (2008).

[0281] Hansen's parameters GVL: δD: 18.50, δP: 14.17, δH: 7.93 (from BIOVIA COSMOquick 2022)

[0282] Reference Example 1: Separation of PET from Polymer Materials

[0283] 1.1: Removal of colorant and / or second polymer (spandex)

[0284] The polymer material (in any processed form, such as textiles, sheets, etc.) is cut / shredded into fragments and placed in a reaction vessel (e.g., flask, tube, reaction vessel). GVL (in a mass-based ratio of polymer material to GVL of 1:1 to 1:100, preferably 1:1-1:20) is added, and the mixture is heated to a temperature in the range of 60°C to 160°C under an inert gas atmosphere using a suitable heating system (e.g., oil bath, heating block, small equipment container). After 0.5-8 h, the mixture is filtered, thereby obtaining GVL rich in colorant and / or spandex and (optionally, colorant-poor) polymer material fragments, wherein the latter is washed with a small amount of GVL. To facilitate the removal of GVL and to accelerate the drying of the (optionally colorant-poor) polymer material fragments, a small amount of acetone is optionally used in a second washing step. The resulting polymer material fragments are dried (e.g., in a vacuum chamber dryer).

[0285] 1.2 Separation of PET

[0286] A shredded polymeric material, still containing PET and cotton and / or PA, from Reference Example 1, is placed in a reaction vessel (e.g., flask, tube, reaction container). Degassed GVL (at a mass-based ratio of GVL:polymeric material of 1:1 to 100:1, preferably 1:1 to 10:1) is added, and the mixture is heated to 185°C at 1013 mbar under an inert gas atmosphere using a suitable heating system (e.g., oil bath, heating block, small equipment container) to obtain a mixture in which the PET is completely dissolved, but solid particles remain in the mixture. After 5-60 min, the mixture is filtered (e.g., heated pressure filtration), thereby obtaining a filter cake containing undissolved polymeric material (cotton and / or PA) and a filtrate containing PET. Optionally, the filter cake is further washed with a small amount of hot GVL.

[0287] Examples 1 to 5 (E1 to E5): Separation of PET from cotton and / or PA

[0288] The polymer material is processed as described in Reference Example 1: if spandex and / or colorant are present, then according to 1.1 and 1.2 of Reference Example 1; if spandex and / or colorant are not present, then only according to 1.2 of Reference Example 1.

[0289] The resulting filtrate obtained from Reference Example 1 was cooled from 185°C to a temperature below 140°C, and then further cooled to a temperature in the range of 20°C to 120°C, wherein PET precipitated.

[0290] Cooling is performed—without adding any additional solvent or component, the filtrate is kept at a temperature range of 160°C to 145°C for at least 5 minutes, preferably at least 10 minutes, more preferably between 5 minutes and 120 minutes, and even more preferably between 10 minutes and 100 minutes. A cooling rate of ≤ 3.0°C / min is used, preferably ≤ 1.5°C / min, more preferably between 0.05 and 3.0°C / min, more preferably between 0.13 and 3.0°C / min, more preferably between 0.15 and 1.5°C / min, and even more preferably between 0.15 and 1.0°C / min.

[0291] During cooling, the viscosity was determined. The experiment (E1) was repeated four times, each time using a new material (E2 to E5), and the maximum viscosity data for E1 to E5 are shown in Table 1 below.

[0292] Table 1

[0293] Maximum viscosity during cooling for examples E1 to E5

[0294]

[0295] It has been observed that a high-viscosity phase appears in the temperature range of 160°C to 145°C, with the maximum viscosity in the range of 5 to 12 Pas, preferably in the range of 5 to 10 Pas.

[0296] The precipitate is filtered and washed with a small amount of GVL. To facilitate GVL removal and expedite the drying of the reclaimed PET powder, a small amount of acetone may be used in the second washing step. The filter cake is also washed with a small amount of GVL.

[0297] Drying is carried out as follows: at a temperature of up to 160°C and a pressure ranging from 1 to 1013 mbar for a period of time ranging from 1 to 24 hours.

[0298] The Mn and Mw values ​​were determined by GPC analysis of the PET contained in the starting material and the re-obtained PET, and are listed in Table 1a below:

[0299] Table 1a

[0300] Mn and Mw values ​​from GPC analysis

[0301]

[0302] Example 6 and Comparison Example 1: Cooling

[0303] Example 1 was repeated twice, differing in the cooling process—without adding any additional solvent or component—so that the filtrate was kept at a temperature range of 160°C to 145°C for less than 5 minutes (Comparative Example 1), and for 90 minutes (Example 6). After cooling to a temperature range of 20°C to 120°C and after the PET had precipitated, the precipitate was filtered under 1 bar of nitrogen using a pressure filter press, and the GVL was collected after filtration. The results are shown in Table 2 below.

[0304] Table 2

[0305] Different cooling programs

[0306]

[0307] It has been found that if the filtrate is cooled to a temperature range of 160°C to 145°C for more than 5 minutes, up to five times the amount of GVL can be recovered after filtration. This is highly beneficial in terms of solvent recycling.

[0308] Example 2: Fiber preparation via spinning

[0309] Precipitated PET from granulated examples E1-E5 and rPET fibers produced by melt spinning from granulated virgin PET (rPET refers to recycled PET, i.e., PET obtained from polymer blend materials). "Virgin" PET refers to PET not obtained by separation from polymer blends, but rather new PET produced through chemical synthesis from corresponding monomers from fossil sources. rPET granules are melted in an extruder (temperature range: 250°C–300°C). The molten rPET is first filtered, then metered in via a pump, and filaments are produced through a spinneret. Fibers are then obtained from the monofilaments. The fibers are then collected on a strip at varying speeds (1000 m / min to 3000 m / min).

[0310] The resulting fibers have an elastic limit in the oriented state greater than 15 cN / tex, preferably in the range of 15 to 70 cN / tex, as determined according to DIN 53816:1993-02. Furthermore, the Young's modulus of the fibers in the oriented state is in the range of 400 to 900 cN / tex, as determined according to DIN 53834-1:1976-02. Exemplarily, the measured / calculated values ​​of the fibers obtained from E4 in the oriented state are as follows:

[0311] Strength: 30.59 cN / tex

[0312] Young's modulus: 739.6 cN / tex

[0313] For comparison, the measured / calculated values ​​of fibers obtained from virgin PET in the orientation state are as follows:

[0314] Strength: 29.79 cN / tex

[0315] Young's modulus: 656.93 cN / tex References

[0316] EP 2 784 110 A1

[0317] US 10,876,240 B2

[0318] DE 2223466 A1

[0319] WO 2016 / 12755 A1

[0320] Wenjun Chen, Yuechao Yang, Xue Lan, Baolong Zhang, Xiaogang Zhang and Tiancheng Mu in Green Chem., 2021, 23, 4065

[0321] WO 2022 / 221832 A1

[0322] Handbuch der mechanischen Fest-Flüssig-Trennung Taschenbuch –29.April 2004 von Klaus Luckert (Herausgeber)

[0323] 5 th Edition 5.1.03 (2008) of the HANSEN Solubility Parameters inPractice (HSPiP)

[0324] "Dyes and Pigments" Metin Açikyildiz, Kübra Günes, Ahmet Gürses Springer, 2016 (ISBN: 10: 3319338900)

[0325] Industrial Organic Pigments - Klaus Hunger, Thomas Heber, Martin U.Schmidt, Friedrich Reisinger, Stefan Wanne Wiley-VCH, 4 th edition, 2018 (ISBN:978-3-527-32608-2)

[0326] Chemistry and Technology of Natural and Synthetic Dyes and Pigments -Ashis Kumar Samanta, Nasser Awwad, IntechOpen, 2020 (ISBN: 9781789859980,9781789859973, 9781839687587)

[0327] Encyclopedia of Color, Dyes, Pigments – Volume 1, Gerhard Pfaff, deGruyter, 2021 (ISBN: 311058588X)

[0328] Heinrich Zollinger: Color Chemistry: Syntheses, Properties, andApplications of Organic Dyes and Pigments.3 rd edition.WILEY-VCH Verlag,Weinheim 2003 (ISBN: 3-906390-23-3)

[0329] Klaus Hunger (Ed.): Industrial Dyes: Chemistry, Properties,Applications.WILEY-VCH Verlag, Weinheim 2003 (ISBN: 3-662-01950-7)

[0330] Hermann Rath: Textbook of Textile Chemistry, including Textile Chemical Technology. 2nd edition. Springer-Verlag, Berlin, Heidelberg 1963 (ISBN: 978-3-662-00065-6); Wilfried Kratzert, Rasmus Peichert

[0331] Dyes. Quelle & Meyer, Heidelberg 1981 (ISBN: 3-494-01021-8)

[0332] Ullmann's Encyclopedia of industrial chemistry, Wiley-VCH, 2000, sections “dyes and pigments” and “dyes, general survey” (ISBN:9783527303854)。

Claims

1. A method for preparing polyester fibers, the method comprising: Provides a polymer blend comprising (i) Polyester, and (ii) One or more components selected from the group consisting of a second polymer, a third polymer, a colorant and a filler, wherein the second polymer and the third polymer are different from each other and different from the polyester of (i); The method includes: (a) Provide the polymer blend and provide a solvent system containing γ-valerol; (b) Optionally, the polymer blend is contacted with the solvent system at a temperature T1 of < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally the filler or a portion thereof, and a residue of the polymer blend depleted in the second polymer and / or colorant and optionally the filler or a portion thereof and containing the polyester, optionally the third polymer and optionally the filler or a portion thereof; (c) Contacting the polymer blend provided in (a) or the residue of the polymer blend obtained optionally in (b) with a solvent system at a temperature T2 > 170°C to obtain a solvent system rich in dissolved polyester and optionally containing the filler or a portion of the filler compared to the solvent system provided in (a), and optionally a residue of the polymer blend, the residue being polyester-poor and optionally containing the third polymer and optionally containing the filler or a portion of the filler; (d) Precipitating the polyester from the solvent system rich in dissolved polyester obtained in (c) to obtain a solvent system containing precipitated polyester and dissolved polyester and optionally the filler or a portion thereof, wherein precipitation includes cooling the solvent system rich in dissolved polyester obtained in (c) compared to the solvent system provided in (a) from T2 to a temperature below 140°C, wherein the cooling is carried out such that the temperature of the solvent system rich in dissolved polyester is maintained in the temperature range of 160°C to 145°C for at least 5 minutes; (e) Fibers are prepared from the precipitated polyester obtained in (d).

2. The method as described in claim 1, wherein, The precipitation in (d) includes cooling the solvent obtained in (c) which is richer in dissolved polyester than the solvent provided in (a) from T2 to a temperature below 140°C, wherein the cooling is carried out such that the temperature of the solvent system rich in dissolved polyester is maintained in the temperature range of 160°C to 145°C for at least 10 minutes, preferably in the range of 5 to 120 minutes, more preferably in the range of 10 to 100 minutes, and even more preferably in the range of 15 to 100 minutes; wherein, preferably, the cooling in (d) is carried out such that the solvent system rich in dissolved polyester has a viscosity in the temperature range of 160°C to 145°C in the range of 1 to 12 Pa s, preferably in the range of 1 to 10 Pa s, as determined according to DIN EN ISO 2555 (2018-09).

3. The method as described in claim 1 or 2, wherein, The cooling of the solvent system in (d) is carried out without the addition of an antisolvent.

4. The method according to any one of claims 1 to 3, wherein, (e) Includes (e.1) Optionally, the precipitated polyester obtained in (d) is melt-extruded to obtain an extrusion containing the polyester; (e.2) Optionally, the extrudate obtained in (e.1) is granulated to obtain an extruded product comprising the polyester in granular form; (e.3) The precipitated polyester obtained in (d) or the extruded product containing the polyester in granular form obtained in (e.2) is used to prepare polyester fibers.

5. The method of claim 4, wherein, The fiber preparation of (e.3) is carried out by a method selected from the group consisting of melt spinning, electrospinning, wet spinning, and matrix spinning, and combinations of two or more of these methods, preferably by melt spinning, wherein the fiber preparation of (e.3) by melt spinning preferably includes (e.3.1) Provide the precipitated polyester obtained in (d) or the polyester obtained in (e.2) in granular form; (e.3.2) The polyester provided in (e.3.1) is melted at a temperature in the range of 250°C to 300°C—preferably in an extruder—to obtain a molten polyester; (e.3.3) Optionally, the molten polyester is filtered to obtain filtered molten polyester; (e.3.4) The molten polyester of (e.3.2) or the filtered molten polyester obtained in (e.3.3) is extruded—preferably through a spinneret—to obtain at least one fiber filament.

6. The method of claim 5, wherein, Fiber preparation includes (e.3.5) Optionally, two or more fiber filaments obtained in (e.3.4) may be combined to obtain fibers; (e.3.6) The at least one fiber filament obtained in (e.3.4) or the fiber obtained in (e.3.5) is collected on a strip, which preferably has a strip speed of at least 500 m / min, more preferably in the range of 1000 to 3000 m / min.

7. The method of any one of claims 1 to 6, wherein if (b) is performed, the method after (b) and before (c) comprises: (v) Wash the residue of the polymer blend obtained in (b) with a washing solvent to obtain a washed residue that is depleted of the second polymer and / or colorant and optionally the filler or a portion thereof, and contains the polyester, optionally the third polymer and optionally the filler or a portion thereof. (w) Optionally, the residue obtained in (v) of the washing is dried.

8. The method according to any one of claims 1 to 7, wherein, The solvent system comprises γ-valerol with a total weight of 100 wt%, at least 50 wt%, 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%, and more preferably at least 99 wt%.

9. The method according to any one of claims 1 to 8, wherein, The polyester is based on 1,2-ethylene glycol, more preferably according to (i) the polyester is based on 1,2-ethylene glycol and terephthalic acid (polyethylene terephthalate, PET), wherein the polyester is PET if the total weight of the polyester is 100% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, and more preferably at least 99% by weight. and / or The second polymer is selected from the group consisting of: polyurethane (PU), polyethylene glycol (PEG), polytetrahydrofuran (pTHF), mixtures of these polymers, and copolymers of these polymers, wherein the second polymer is more preferably PU or a copolymer of PU and PEG and / or pTHF, more preferably spandex; and / or The third polymer is selected from polypropylene (PP), polyethylene (PE), polyamide (PA), natural polymers such as cotton, viscose fiber, flax, and mixtures of two or more thereof.

10. The method according to any one of claims 1 to 9, wherein, In (c), the residue of the polymer blend provided in (a) or optionally the polymer blend obtained in (b) is contacted with the solvent system at a temperature T2 of >170°C to 200°C, more preferably at a temperature in the range of 175°C to 190°C.

11. The method according to any one of claims 1 to 10, wherein, Based on the total weight of the solvent system containing one or more antisolvents being 100 wt%, the solvent system in step (d) contains less than 5 wt%, preferably less than 4 wt%, more preferably less than 3 wt%, more preferably less than 2 wt%, and more preferably less than 1 wt% of the one or more antisolvents.

12. A polyester fiber, which is obtained or can be obtained by the method of any one of claims 1 to 11; wherein preferably, the polyester fiber has an elastic limit in the oriented state greater than 15 cN / tex, preferably in the range of 15 to 70 cN / tex, as determined according to DIN 53816:1993-02; and / or wherein preferably, the polyester fiber has a Young's modulus in the oriented state in the range of 400 to 900 cN / tex, as determined according to DIN 53834-1:1976-02.

13. Use of the polyester fiber as described in claim 12 for the preparation of textiles.

14. A method for preparing a product, the method comprising: (I) Providing the polyester as described in claim 12; (II) Textiles are prepared from the polyester provided in (I).

15. The method of any one of claims 1 to 11, further comprising the following steps: - The residue that is obtainable or acquireable by the method of any one of claims 1 to 11, preferably obtainable or acquireable from step (d), more preferably obtainable or acquireable by the method of any one of claims 1 to 11, preferably obtainable or acquireable from step (d), comprising at least a third polymer, is converted. To obtain one or more monomers, polymers, or polymer products; Preferably, the monomer is a diol or polyol, preferably butanediol; an aldehyde, preferably formaldehyde; a diisocyanate or polyisocyanate, preferably methylene diphenyl diisocyanate (MDI), polymeric methylene diphenyl diisocyanate (pMDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI); an amide, preferably caprolactam; an olefin, preferably styrene, ethylene and norbornene; an alkyne; a (di) ester, preferably methyl methacrylate; a monoacid or diacid, preferably adipic acid or terephthalic acid; a diamine, preferably hexamethylenediamine or nonanediamine; or a sulfone, preferably 4,4'-dichlorodiphenyl sulfone; and / or Preferably, the polymer is and / or the polymer product comprises polyamide (PA), preferably PA 6 or PA 66; a polyisocyanate addition polymer, preferably polyurethane (PU), thermoplastic polyurethane (TPU), polyurea or polyisocyanurate (PIR); low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrene (PS), polyacrylonitrile butadiene styrene (ABS), polystyrene acrylonitrile (SAN), polyacrylate styrene acrylonitrile polyacrylate (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene) -Isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate (PBAT), polyester (PES), polyethersulfone (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulfone (PSU), polyphenylene sulfone (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene ether) (PPO), poly(p-phenylene ether) (PPE); or copolymers or mixtures thereof; and / or Preferably, the polymer and / or the polymer product is one or more of the following: - Automotive parts; preferably cylinder head covers, engine hoods, turbocharger housings, turbocharger baffles, intake pipes, intake manifolds, connectors, gears, fan wheels, coolant tanks, housings, heat exchanger housings, coolant coolers, turbocharger coolers, thermostats, water pumps, radiators, fasteners, battery system components for electric vehicles, dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C, or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper protective housings, decorative grilles, covers, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushioning pads or coatings; - Fabric; preferably shirts, trousers, sweaters, boots, shoes, shoe soles, bodysuits or jackets; - Electrical components; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foil, wire, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, spools, lamps, diodes, LEDs, transistors, connectors, voltage regulators, integrated circuits (ICs), processors, controllers, memory, sensors, microswitches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, gaskets, bolts, strips, slide-in guides, screws, nuts, membrane hinges, spring hooks (clamp-in) or spring tongues; - Consumer goods, agricultural products, or pharmaceutical products; preferably tennis strings, climbing ropes, bristles, brushes, artificial turf, 3D printed filaments, lawnmowers, zippers, hook and loop fasteners, paper machine netting, extrusion coatings, fishing lines, fishing nets, offshore lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyors, sliding bearings, rollers, wheels, gears, ring gears, screws and spring dampers, hoses, pipes, cable sheaths, sockets, switches, cable ties, fan wheels, carpets, cosmetic boxes or bottles, mattresses, cushioning pads, insulating materials, detergents, dishwasher detergent blocks or powders, shampoos, shower gels, bath gels, soaps, fertilizers, fungicides, or pest control agents; - For packaging in the food industry, single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film, or laminated film are preferred; or - Structural components, preferably rotor blades, insulating materials, frames, housings, walls, coatings, or partition walls.

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