Method for separating a polymer blend

Abstract

A first aspect of the invention relates to a method for separating a polymer blend, wherein the polymer blend comprises (I) a polyester and (II) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and 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 comprising 1 -methylpyrrolidin-2-one; (b) optionally contacting the polymer blend with the solvent comprising 1- methylpyrrolidin-2-one at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising 1 -methylpyrrolidin-2-one, which is enriched in dissolved optional second polymer, in optional colorant and in optional additive or a part thereof; and a residue of the polymer blend, which is depleted of optional second polymer, of optional colorant and of optional additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof; and (c) contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) with a solvent comprising 1 -methylpyrrolidin-2-one at a temperature T2 in the range of from > 150 to < 160°C, thereby obtaining a solvent, which comprises 1 -methylpyrrolidin-2-one and which is enriched in dissolved polyester compared to the solvent provided in step (a) and comprises optionally at least a part of the additive, and optionally a residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof. A second aspect of the invention is directed to a polyester obtained or obtainable from the method according to the first aspect of the invention. In a third aspect, the invention is related to the use of the polyester of the second aspect, and a fourth aspect of the invention is directed to a method for preparing a product comprising (I) providing a polyester of the second aspect of the invention; and (II) preparing a textile, a fiber, a packaging, a plastic, an automotive part, an electronic part from the polyester provided in step (I).

Description

240375W001- 1-Method for separating a polymer blendA first aspect of the invention relates to a method for separating a polymer blend, wherein the polymer blend comprises (I) a polyester and (II) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and 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 comprising 1 -methylpyrrolidin-2-one (NMP); (b) contacting the polymer blend with the solvent comprising NMP at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising NMP, which is enriched in dissolved optional second polymer, in optional colorant and in optional additive or a part thereof; and a residue of the polymer blend, which is depleted of optional second polymer, of optional colorant and of optional additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof; and / or (c) contacting the polymer blend provided in step a or the residue of the polymer blend obtained in step (b) with a solvent comprising NMP at a temperature T2 in the range of from > 150 to < 160°C, thereby obtaining a solvent, which comprises NMP and which is enriched in dissolved polyester compared to the solvent provided in step (a) and comprises optionally at least a part of the additive, and optionally a residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof. A second aspect of the invention is directed to a polyester obtained or obtainable from the method according to the first aspect of the invention. In a third aspect, the invention is related to the use of the polyester of the second aspect, and a fourth aspect of the invention is directed to a method for preparing a product comprising (I) providing a polyester of the second aspect of the invention; and (II) preparing a textile, a fiber, a packaging, a plastic, an automotive part, an electronic part from the polyester provided in step (I).The demand for polymeric materials has drastically increased over the last decades. However, the poor biodegradability has led to large amounts of plastic waste which is worldwide usually incinerated thereby losing valuable materials and generating huge CO2 emissions. Even worse is landfill due to the poor biodegradability. Polymeric materials have been used extensively in the packaging sector, for example, in beverage packaging or food packaging. The vast majority of food and drink today is packaged within plastic bottles and containers, made from, for example, polymeric materials comprising polyethylene terephthalate (PET). PET is also a main component of clothing nowadays. As these materials typically have poor biodegradability and are also still valuable products, it is desirable for these plastics to be recovered and recycled. The same applies for polymer blends comprising, for example, polybutylene terephthalate (PBT), which are normally used in the electronic field, for example, as insulating sheath in cable applications.Although recycling processes have been adopted to convert these waste materials into new production materials, there are still many problems associated with recycling and recovery of polymeric materials. Recycling of polyester, especially polyethylene terephthalate (PET), containing textiles is difficult due to mixture with other polymers, for example cotton, and other components, such as colorants etc. Therefore, a closed-loop mechanical recycling process240375W001- 2- is not possible without separation from other materials. Also, for other PET end-of-life sources, often mechanical recycling is hindered by contaminants and mixed polymer waste streams. The same problems exist for polymer blends with other polyesters, especially polybutylene terephthalate (PBT).An approach for recovery of polymeric materials includes the dissolution of the polymeric material. WO 2016 / 12755 A1 discloses an extraction of polyesters from packaging, wherein a first solvent is used for removal of 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 in Green Chem., 2021 , 23, 4065) describe a process for dissolution and accelerated alkaline hydrolysis of PET using gamma valerolactone (GVL). However, GVL is commercially available only in limited amounts and the process is more energy-consuming.Methods for discoloration and / or dissolution of polyesters and separation of polymer blends comprising polyesters such as PET based on the use of GVL were meanwhile developed and are for example described in WO 2023 / 187053 A1 . However, especially in view of energy consumption, it has to be noted that using GVL requires some amount of energy since for dissolution of polyesters, a heating to temperatures above 170°C is required, wherein said temperature has to be maintained for a prolonged period of time, i.e. a constant energetic input for heating is required.The object underlying the present invention was thus the provision of an improved process, which enables a simple separation of polyesters from other materials comprised in a polymer blend, which also enables high recovery rates of the polyester while not harming the relevant properties of the polymeric material such as its number average weight Mn, and which allows for reducing the energetic demand.In a first aspect, the invention is directed to a method for separating a polymer blend, wherein the polymer blend comprises(I) a polyester and(II) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and 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 comprising 1 -methylpyrrolidin-2-one (NMP);(b) contacting the polymer blend with the solvent comprising NMP at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising NMP, which is enriched in dissolved optional second polymer, in optional colorant and in optional additive or a part thereof; and a residue of the polymer blend, which is depleted of optional second polymer, of optional colorant and of optional additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof; and / or240375W001- 3-(c) contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) with a solvent comprising NMP at a temperature T2 in the range of from > 150 to < 160°C, thereby obtaining a solvent, which comprises NMP and which is enriched in dissolved polyester compared to the solvent provided in step (a) and comprises optionally at least a part of the additive, and optionally a residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof.Preferably, the invention relates to a method for separating a polymer blend, wherein the polymer blend comprises(I) a polyester and(II) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and 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 comprising 1 -methylpyrrolidin-2-one;(b) optionally contacting the polymer blend with the solvent comprising 1 -methylpyrrolidin-2-one at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising 1-methylpyrrolidin-2-one, which is enriched in dissolved optional second polymer, in optional colorant and in optional additive or a part thereof; and a residue of the polymer blend, which is depleted of optional second polymer, of optional colorant and of optional additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof; and(c) contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) with a solvent comprising 1 -methylpyrrolidin-2-one at a temperature T2 in the range of from > 150 to < 160°C, thereby obtaining a solvent, which comprises 1 -methylpyrrolidin-2-one and which is enriched in dissolved polyester compared to the solvent provided in step (a) and comprises optionally at least a part of the additive, and optionally a residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof.It has now been surprisingly found that using a solvent comprising NMP in the above-described method for separation of a polymer blend comprising polyester resulted in recovery of the polyester in good yields and purities. Furthermore, not only a stop of decrease regarding the mass average molecular weight Mw of the polyester, which is recovered from the polymer blend, could be achieved but also the number average molecular weight Mn increased. Additives, colorants and further polymers, if present, could effectively be removed and also a decrease of intrinsic viscosity could be avoided. Moreover, it was possible to obtain these effects while a distinctively lower temperature was required both for step (b) and for step (c) compared to, for example, a solvent such as GVL, which enables a significant energy saving. Furthermore, it was shown that for using NMP at temperatures in the range of from > 150 to240375W001- 4-< 160°C, the re-obtained NMP was only slightly colored compared to temperatures above 160°C, where the re-ob- tained solvent NMP was strongly colored. Thus, the temperature range of from > 150 to < 160°C does not only offer advantages in view of energy saving but also in view of recyclability of the used solvent.Contacting the polymer blend with the solvent comprising NMP is done in step (b) at a temperature T1 of < 140 °C, preferably of < 135°C. More preferably, T1 according to step (b) is in the range of from 120 to < 140°C, more preferably in the range of from 120 to < 135°C.Contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) is done in step (c) with a solvent comprising NMP at a temperature T2 in the range of from > 150 to < 160°C. Preferably, T2 according to step (c) is in the range of from 151 to 159°C.A "polymer blend” means a combination of at least one polymer - here a polyester (I) - with at least one further component, which is at least another component, selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and third polymer are different from each other and different from the polyester of (I). These components are combined in the polymer blend combined with each other in any suitable way."Contacting” in step (b) and step (c) preferably means that the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) respectively is at least partially immersed in the solvent. Preferably, the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) respectively is at least partially immersed in the (first or second) solvent in 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 step (a) or of the surface of the residue of the polymer blend obtained in step (b) respectively are in contact with the solvent, based on the total respective surface being 100%."Depleted in said optional second polymer, of said optional colorant and optionally of additive or part thereof' in step (b) means that at least 50 weight-%, preferably at least 60 weight-%, more preferably at least 70 weight-%, more preferably at least 80 weight-%, more preferably at least 90 weight-%, more preferably at least 95 weight-%, of the respective component(s), based on the total amount of the respective component(s), which was initially comprised in the polymer blend provided in step (a) being 100 weight-%, are no longer comprised by the polymer blend but are rather dissolved in the solvent. Consequently, also "enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof” regarding the solvent obtained in step (b) means that at least 50 weight-%, preferably at least 60 weight-%, more preferably at least 70 weight-%, more preferably at least 80 weight-%, more preferably at least 90 weight-%, more preferably at least 95 weight-%, of the respective components), based on the total amount of the respective component(s), which was initially comprised in the polymer240375W001- 5- blend provided in step (a) being 100 weight-%, are dissolved in the solvent. The same applies for "depleted of polyester” regarding the residue of the polymer blend obtained in step (c) and also for "enriched in dissolved polyester” regarding the solvent obtained in step (c).The expression "optional additive or a part thereof” in step (b) means that, if one or more additive(s) is / are present in the polymer blend provided in step (a), which is / are soluble in a solvent comprising NMP at a temperature T1 , said soluble additive(s) is / are also dissolved in the solvent, which is obtained in (b). In case that not only a soluble additive is present in the polymer blend provided in step (a) but also an additive, which is not soluble in a solvent comprising NMP at a temperature T1 , said insoluble additive remains in the residue of the polymer blend, which is obtained in step (b). In cases where the polymer blend provided in step (a) comprises only additive(s) soluble in a solvent comprising NMP at a temperature T1 , no additive remains in the residue of the polymer blend. In cases where only addi- tive(s) insoluble in a solvent comprising NMP at a temperature T 1 are contained in the polymer blend provided in step (a), all additive(s) remain(s) in the residue of the polymer blend obtained in step (b). In cases where the polymer blend provided in step (a) comprises additive(s) insoluble in a solvent comprising NMP at a temperature T2 and addi- tive(s) soluble in a solvent comprising NMP at a temperature T2, at least a part of the additives, i.e. the soluble addi- tive(s) is / are comprised in the solvent, which is obtained in step (c) and the residue of the polymer blend, which is obtained in step (c) still comprises the insoluble additive(s).Contacting the polymer blend is done in step (b) with the solvent comprising NMP and contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) is done in step (c) with a solvent comprising NMP. Preferably, the solvent comprises NMP and optionally one or more solvent(s) selected from the group consisting of water and organic solvents having a log Kow in the range of from -1.6 to +1.6, more preferably selected from the group consisting of water, C5 to C12 alkane, aliphatic C1 to C10 alcohol, C3 to C10 ketone, C2 to C10 cyclic ketone, HO-[C1 to C10 alkyl-O-]n-H, with n being an integer in the range of from 2 to 1000, C1 to C10 alkyl-O-C3 to C10 alkyl ether, C3 to C10 cyclic ether, optionally substituted with one or more C1 to C6 alkyl group(s), C6 to C10 aromatic hydrocarbon, optionally substituted with one or more C1 to C6 alkyl group(s), C2 to C10 aliphatic ester, C8 to C11 aromatic ester, C5 to C10 cyclic carboxylic ester (lactone), C3 to C12 amide, preferably R1R2N-C(=O)-R3, wherein R1, R2are independently a C1 to C4 alkyl group and R3is selected from the group consisting of C1 to C9 alkyl group, C1 to C10 ester group and C1 to C6 ether group, unsubstituted C3 to C6 lactame, C3 to C4 or C6 lac- tame substituted with one or more substituent selected from C1 to C6 alkyl group, C1 to C6 ester group and C1 to C6 ether group, and C5 imidazolidine, optionally substituted with one or more C1 to C6 alkyl group(s), C5 to C7 imidaz- olidone, optionally substituted with one or more C1 to C6 alkyl group(s), wherein preferably at least 1 weight-%, more preferably at least 5 weight-%, more preferably at least 10 weight-%, more preferably at least 20 weight-%, more preferably at least 30 weight-%, more preferably at least 40 weight-%, more preferably at least 50 weight-%, more preferably at least 60 weight-%, more preferably at least 70 weight-%, more preferably at least 80 weight-%, more preferably at least 90 weight-%, more preferably at least 95 weight-% of the solvent consists of NMP, based on the total weight of the solvent being 100 weight-%.240375W001- 6-Preferably, in step (b) and in step (c) the same solvent comprising NMP is used.A polymer blend is provided in step (a), wherein the polymer blend comprises (i) a polyester and (ii) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and third polymer are different from each other and different from the polyester of (i). The polyester is preferably based on 1 ,4-butanediol or 1 ,2-ethandiol, more preferably the polyester according to (i) is selected from the group consisting of a polymer based on 1 ,4-butanediol and terephthalic acid (polybutylene terephthalate, PBT), a polymer based on 1 ,2-ethanediol and terephthalic acid (polyethylene terephthalate, PET), a co-poly- mer of 1 ,4-butanediol, adipic acid and terephthalic acid (polybutylenadipat-terephthalat, PBAT), a polymer of 1 ,2- ethanediol and 2, 5-fu randicarboxy I ic acid (polyethylene furanoate, PEF) and mixtures of two or more of these (copolymers, more preferably, the polyester comprises at least PET or PBT, more preferably the polyester is PET or PBT or a mixture of PET and PBT.The second polymer is preferably 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 a copolymer of PU and PEG and / or pTHF, more preferably spandex (copolymer of PU and PEG or of PU and pTHF). In some preferred embodiments, the second polymer is preferably "Spandex”, which is preferably a copolymer of polyurethane and polyethylene glycol and / or polytetrahydrofurane, more preferably Spandex is a copolymer of polyurethane and polyethylene glycol or a copolymer of polyurethane with polytetrahydrofurane. Spandex is presumably not only dissolved in step (b), but furthermore at least partially degraded - this is apparent from, for example, Differential Scanning Calorimetry (DSC) measurements. The third polymer is preferably selected from the group consisting of polyolefins, preferably polyethylene (PE) and polypropylene (PP), polyamide (PA), natural polymer, preferably wool, cotton or viscose, mixtures of two or more of these polymers and copolymers of two or more of these polymers, wherein the third polymer is preferably selected from PA, wool, cotton, viscose and mixtures of two or more of these polymers. PA comprises preferably PA6 and PA66; however, in some embodiments PA6 is excluded as third polymer and preferably, the polymer blend provided in step (a) does not comprise PA6. If present in the polymer blend, the solvent obtained in step (c), which is enriched in dissolved polyester is separated from the residue, which comprises at least one of PP, PE, PA and / or natural polymer. All polymers not soluble together with the polyester, preferably all polymers not soluble together with the polyester in a solvent comprising NMP under the conditions of step (c) as defined above, are called herein "insoluble polymers”.The colorant is preferably selected from the group consisting of dye and optical brightener and mixtures of dye and optical brightener. A "colorant” is a substance that cause the change of color impression of a material. This comprises dyes, which absorb wavelength intervals of visible light (400 to 780 nm) and optical brighteners, which amplify the light emission of a material through UV light adsorption and emittance of visible light (through fluorescence), i.e. an optical brightener converts radiation that is not visible to the human eye (< 400nm) into visible fluorescence radiation of the blue-red spectral range (400 to 600 nm). Colorants usable or used for changing the color impression of polymeric materials are known to the skilled person. In the context of the present invention, the term "dye” means240375W001- 7- any kind of dye such as dye, pigment, dispersion, wherein a dye is, for example, one or more selected from the group consisting of acid dye, basic dye, direct dye, disperse dye, azoic dye, food dye, solvent dye, organic dye, inorganic pigment, organic pigment, disperse ink, reactive ink, oxidation dye, reactive dye, sulfur dye, mordant dye and vat dye. The term "optical brightener” comprises optical brightening agents, fluorescent brightening agents, and fluorescent whitening agents.Overviews of colorants for polymeric materials can be found, for example, in "Dyes and Pigments” Metin Agikyi Idiz, Kubra Giines, Ahmet Giirses Springer, 2016 (ISBN: 10 : 3319338900); Industrial Organic Pigments - Klaus Hunger, Thomas Heber, Martin U. Schmidt, Friedrich Reisinger, Stefan Wanne Wiley-VCH, 4thedition, 2018 (ISBN: 978-3- 527-32608-2); Chemistry and Technology of Natural and Synthetic Dyes and Pigments - Ashis Kumar Samanta, Nasser Awwad, IntechOpen, 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. 3rdedition. WILEY-VCH Verlag, Weinheim 2003 (ISBN: 3-906390-23-3); Klaus Hunger (Ed.): Industrial Dyes: Chemistry, Properties, Applications. WILEY-VCH Verlag, Weinheim 2003 (ISBN: 3-662-01950-7); Hermann Rath: Lehrbuch der Textilchemie. einschl. der textilchemischen Technologie. 2nd edition. Springer-Verlag, Berlin, Heidelberg 1963 (ISBN: 978-3-662-00065-6); Wilfried Kratzert, Rasmus Peichert: Farbstoffe. Quelle & Meyer, Heidelberg 1981 (ISBN: 3-494-01021-8); Ullmann's Encyclopedia of industrial chemistry, Wiley-VCH, 2000, sections "dyes and pigments” and "dyes, general survey” (ISBN: 9783527303854).Preferably, colorants in the context of the present invention are colorants which are not covalently bound to the polyester and / or the third polymer if present.In some preferred embodiments of the method, depleted in colorant regarding the residue of the polymer blend obtained in step (b) means that the L*a*b* values of the residue, which is depleted in colorant compared to the polymer blend provided in step (a), change in that: the absolute value of a* changes, preferably by at least 0.2; and / or, preferably and, the absolute value of b* changes, preferably by at least 0.2; and / or, preferably and, the L* value increases, preferably by at least 4, each compared to the L*a*b* values of the polymer blend provided in step (a), wherein L*a*b* values are determined according to DIN 5033 and DIN EN ISO 11664-1.6.The method according to the present invention can be suitable to achieve a residue of the polymer blend in step (b) with L*a*b* values of the residue which are changed compared to the polymer blend provided in step (a) in that: the absolute value of a* changes, preferably by at least 0.2, more preferably by at least 0.3, more preferably by at least 0.4, more preferably by at least 0.5, more preferably by at least 0.6, more preferably by at least 0.7, more preferably by at least 0.8, more preferably by at least 0.9, more preferably by at least 1.0, more preferably by at least 1.1,240375W001- 8- more preferably by at least 1.2, more preferably by at least 1.3, more preferably by at least 1.4, more preferably by at least 1.5, more preferably by at least 1.6; and / or, preferably and, the absolute value of b* changes, preferably by at least 0.2, more preferably by at least 1, more preferably by at least 2, more preferably by at least 3, more preferably by at least 4, more preferably by at least 5, more preferably by at least 6, more preferably by at least 7, more preferably by at least 8, more preferably by at least 9; and / or, preferably and, the L* value increases, preferably by at least 4, more preferably by at least 5, more preferably by at least 10, more preferably by at least 15, more preferably by at least 20, more preferably by at least 25, more preferably by at least 30, more preferably by at least 35, more preferably by at least 40, each compared to the L*a*b* values of the polymer blend provided in step (a), wherein L*a*b* values are determined according to DIN 5033 and DIN EN ISO 11664-1.6.These L*a*b* value changes may especially apply for dark colored starting material having an L*of < 80, preferably of < 50.The expression "irrespective of the color” means that, even if analytics are normally done for materials of each color separately, the definitions given above apply for single-colored polymeric materials, but also for polymeric materials having a plurality of colors and mixtures of pieces of polymeric materials, wherein each piece has its own color or its own color mix.The condition of being "depleted in colorant”, which is expressed above based on quantitative L*a*b* values is also identifiable visually by the eye: The polymer blend provided in step (a), if not being white, i.e. colorless, has a certain color, wherein the residue obtained is lighter and whiter respectively. This applies especially for all colorants not being optical brighteners. Depleted in colorant regarding the residue obtained means, especially with respect to optical brighteners being the colorant, that the intensity of emitted fluorescence radiation (emission), preferably in the range of from 400 to 600 nm, is reduced for the residue obtained when irradiated with light with a wavelength in the range of from 250 to 400 nm compared to the intensity of emitted fluorescence radiation (emission), preferably in the range of from 400-600 nm, of the polymer blend provided in step (a).Methods for determination of the intensity of emitted fluorescence radiation are known to the skilled person, for example, the determination can be made visually by using an UV lamp, by fluorescence determination or determination of quantum yield.The additive is preferably selected from the group consisting of softener, water repellent, flame retardant, UV filter, plasticizer, filler and mixtures of two or more thereof. A softener is preferably selected from the group consisting of silicone based softener, fatty alcohol, fatty acid, fatty amino acid, fatty acid derivate, fatty amino acid derivate, polyethylene, alkyl imidazolinium salt, bisquaternary ammonium salt and mixtures of two or more thereof, wherein "fatty”240375W001- 9- refers to an alkyl chain having in the range of from 8 to 22 C atoms; more preferably selected from the group consisting of polydiorganosiloxane (preferably polydimethylsiloxane and / or derivative of polydimethylsiloxane), fatty alcohol, condensation product of fatty amino acid with ethylene oxide, ethoxylated fatty acid, ethoxylated fatty alcohol, paraffin, oxidized polyethylene wax, optionally in combination with quaternary ammonium compounds, wherein the quaternary ammonium compound is preferably selected from the group of N+R1R2R3R4, wherein R1and R2are independently selected from C1 to C3 alkyl and , optionally substituted with a hydroxyl group, and R3and R4are independently selected from C8 to C22 alkyl and C2 to C4 alkyl-C(=O)-O- C8 to C22 alkyl; wherein the ammonium compound is more preferably selected from dimethyl (dihydrogenated tallow) ammonium, dimethyl distearyl ammonium and mixtures of these two, wherein the positive charge of the quaternary ammonium compound is preferably compensated by one or more anions, preferably selected from chloride, methyl sulfate and mixture of these two anions. A water repellent is preferably selected from the group consisting of siloxane (preferably unsaturated (e.g. vinyl-terminated) polydialkylsiloxane, hexamethyldisiloxane or a mixture of two or more thereof), silane (preferably hexatrimethoxysilane), paraffin (preferably in dispersion with aluminum salts, more referably stearic acid with aluminum or zirconium salts), fat modified melamine (preferably stearic acid-melamine derivate), silicone, tin octoate, fluorocarbon (preferably selected from perfluorohexanoic acid (PFHA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and mixtures of two or more thereof), acrylic polymers containing perfluoroalkyl chains, alkylphenol ethoxylate (APEO), and mixtures of two or more thereof. Regarding the acrylic polymers containing perfluoroalkyl chains, the length of the perfluorinated alkyl side chains is in the range of from 8 to 10 carbon atoms. The small spacer group, mostly ethylene, can be modified to improve emulsification and solubility of the polymer. Comonomers such as stearyl- or laurylmethacrylate, butylacrylate, methylol- or epoxy-functional acrylates and block copolymers from a, co dihydroxydimethylpolysiloxane. A flame retardant is preferably selected from the group consisting of halogenated flame retardant (preferably hexabromocyclododecane, decabromodiphenyl ether, bis(hexa- chlorocyclopentadieno)cyclo-octane, trisdibromopropylphosphate, decabromodiphenyl oxide (DBDPO) and mixtures of two or more thereof), non-halogenated flame retardant, phosphor-containing flame retardant, phosphor-free flame retardant (preferably selected from the group consisting of tetraethoxysilane (TECS), (3-aminopropyl) triethoxysilane (APTES), 3-glycidyloxypropyl trimethoxysilane (GPTMS) and mixtures of two or more thereof), compound without halogenates and phormol, compound with halogenates or phormol, metal hydroxide, and mixtures of two or more thereof; more preferably from the group consisting of oligomeric reaction products with urea of hydroxymethyl phosphonium chloride, aluminiumhydroxid, calcium carbonate, and mixtures of two or more thereof. A UV filter is preferably selected from the group of hydroxyphenone derivative (preferably from the group of hydroxyphenyl triazines), benzotriazole (preferably 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1 -phenylethyl)), oxanilide, hydroxyphenyl benzotriazole, derivative of Hindered Amine Light UV stabilizers (HALS derivatives), benzothiazinone, salicyclic acid ester, cinnamic acid ester, resorcinol monobenzoate, hydroxybenzoic acid ester, cyanoacrylate, benzophenone, and mixtures of two or more thereof. A plastiziser is preferably selected from the group consisting of phthalic acid ester, adipic acid ester, terephthalic acid diester, trialkyl trimellitate, 1 ,2-cyclohexandicarboxylic diester, 1,3- cyclohexandicarboxylic diester, 1 ,4-cyclohexandicarboxylic diester, and mixtures of two or more thereof.240375W001- 10-Further additives are adhesive, thickener, antifoam agent, finishing agent (for example water / oil / stain repellent, flame retardant, anticrease agent, biocide), binder, surfactant (for example, softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidant, UV filter, emulsionant, fixing agent, washing dispersant, profiling agent.A "filler” is, for example, glass fiber, coal fiber, carbon black, inorganic salt (for example, talc, disodium carbonate). These components are known to the skilled person. Filler®, if present, form part of the residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof, obtained in step c).As indicated above, contacting of the polymer blend is done in step (b) with the solvent comprising NMP and contacting of the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) is done in step (c) with a solvent comprising NMP. Preferably, step (b) and / or step (c) are done in a gaseous atmosphere comprising at least one inert gas, more preferably in a gaseous atmosphere comprising nitrogen. Preferably, step (b) and / or step (c) are done at a pressure in the range of from 800 to 1200 hPa, preferably in the range of from 900 to 1100 hPa, more preferably in the range of from 1000 to 1100 hPa or at a pressure pressure in the range of from 1013 to 200,000 hPa, preferably in the range of from 1013 to 100,000 hPa.In some preferred embodiments of the method for separating a polymer blend, at least one of step (b) and step (c), preferably step (b) and / or step (c), is / are conducted in continuous manner or discontinuous manner. According to this embodiment, step (b) and / or step (c) is either carried out under a flow of the solvent comprising NMP (continuous manner) or in a stationary mode (discontinuous manner, batch mode). The contacting is done in one or more vessel , for example, one or more vessels are filled with colored polymer blend material and the solvent comprising NMP is directed through this vessel / these vessels with a specific flow. A preferred example is a, preferably stirred, vessel cascade. In some preferred embodiments of the method for separating a polymer blend, at least one of step (b) and step (c), preferably step (b) and / or step (c), is / are in counter current mode. According to this embodiment, step (b) and / or step (c) is carried out in counter current mode. For example, if the contacting of step (b) is done within a vessel, the solvent comprising NMP enters the vessel from one direction (either side or top / bottom) and the polymer blend enters the vessel from an another, preferably an opposite, direction. In a preferred constellation wherein a vertically arranged vessel is used, the solvent comprising NMP enters the vessel from the bottom and the polymer blend enters the vessel from the top.Irrespective whether step (b) and step (c), preferably step (b) and / or step (c), is / are conducted in continuous manner or discontinuous manner and irrespective whether co current mode or counter current mode are applied, it is preferred that the solvent is preheated to the respective temperature (T1, T2) and then contacted with the polymer blend or the respective residue.240375W001- 11-In some preferred embodiments of the method for separating a polymer blend, at least one of step (b) and step (c), preferably both step (b) and step (c), is / are conducted under mechanical intermixing, wherein mechanical intermixing preferably comprises one or more methods selected from stirring, blending, and ultrasound.As indicated above, contacting of the polymer blend is done in step (b) with the solvent comprising NMP and contacting of the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) is done in step (c) with a solvent comprising NMP. Preferably, the mass based ratio polymer blend : solvent in step (b) and / or in step (c) is in the range of 1 :1 to 1 :100, preferably in the range of from 1:1 to 1 :20.Preferably, step (b) comprises:(b.1) contacting the polymer blend with the solvent comprising NMP at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising NMP, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof; and a residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof;(b.2) separating the solvent, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof, and the residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof obtained in step (b.1 ), preferably by a physical separation method, thereby obtaining a separated solvent, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof compared to the solvent provided in step (a) and the residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof.Physical separation methods may comprise mechanical separation methods, thermal separation methods and mixed forms of mechanical and thermal separation.The separation in step (b.2) is done by methods and means known to the skilled person, especially solid-liquid separation methods such as filtration, for example, heated pressure filtration, sedimentation or centrifugation (see Hand- buch der mechanischen Fest-Flussig-Trennung Taschenbuch - 29. April 2004 von Klaus Luckert (Herausgeber)).Colorants and / or second polymer, if present in the polymer blend, especially in the polyester, remain at least partially in the separated solvent obtained in step (b.2). In some preferred embodiments of the process, step (b.2) is done at a pressure in the range of from 800 to 200,000 hPa.Preferably, step (b) further comprises:240375W001- 12-(b.3) washing the separated residue of the polymer blend obtained in step (b.2) at least once with a washing solvent comprising NMP and optionally one or more solvent(s) selected from the group indicated above, thereby obtaining a washed residue;(b.4) optionally drying the washed residue obtained in step (b.3).Step (b.3) and optional step (b.4) are conducted preferably if the polymer blend provided in step (a) comprises a colorant and / or a second polymer, in order to reduce the amount of colorant and / or a second polymer carried along by the residue obtained in step (b.2). In some preferred embodiments of the process, step (b.3), step (b.4) is / are done at a pressure in the range of from 800 to 200,000 hPa.When polymer blend comprises at least a third polymer, the method preferably comprises d) separation of the solvent system, which is enriched in dissolved polyester obtained in step (c) from the residue obtained in step (c), thereby obtaining a solvent enriched in dissolved polyester, which is free of third polymer, and a residue comprising at least the third polymer, wherein the separation is done by heated solid-liquid separation, preferably at a temperature in the range of T2 ± 20°C, more preferably at a temperature in the range of T2 ± 10°C.Heated solid-liquid separation is, for example, heated filtration, wherein the solution, filter, and funnel are heated, preferably heated so that each has temperature T2 ± 20°C or T2 ± 10°C. In some embodiments, it is preferred that the heated filtration is done under a pressure of >1 bar, more preferably at a pressure in the range of from 1 bar to 30 bar, preferably in the range of from 1 to 10 bar, more preferably in the range of from 1 to 6 bar (heated pressure filtration). Other means and methods for the separation are known to the skilled person such as non-heated filtration. Further methods and means for solid-liquid separation are known to the skilled person, especially sedimentation or centrifugation (see Handbuch der mechanischen Fest-Flussig-Trennung Taschenbuch - 29. April 2004 von Klaus Lucked (Herausgeber) In some preferred embodiments with heated filtration, the filter and the residue comprising at least the third polymer (which is retained on the filter), preferably after the solvent system, which is enriched in dissolved polyester, has passed through the filter, is rinsed with solvent for one or more times, preferably with a solvent having the same composition as used in step (c).The method preferably further comprises(e) optionally after heated filtration according to step (d), cooling the solvent obtained in step (c) or in step (d), which is enriched in dissolved polyester compared to the solvent provided in step (a), to a temperature below T2 preferably below 150°C, more preferably below 140°C, more preferably below 120°C; thereby obtaining a precipitated polyester and a solvent, which is depleted in dissolved polyester.The temperature to which the cooling is done is a temperature below T2°C, preferably below 150°C, more preferably below 140°C, more preferably below 120°C and, in each case, above 0 °C, preferably above 5 °C, more preferably above 10 °C. The optional filtration according to step (d) and the precipitation according to step (e) are preferably240375W001- 13- done at a pressure in the range of from 800 to 1200 hPa, preferably in the range of from 900 to 1100 hPa, more preferably in the range of from 1000 to 1100 hPa. Cooling in step (e) is preferably done without addition of antisolvents. In some embodiments, only a small amount of one or more antisolvent(s) is / are added to and / or is / are present in the solvent in step (c), wherein a small amount means that less than 5 weight-%, preferably less than 4 weight-%, more preferably less than 3 weight-%, more preferably less than 2 weight-%, more preferably less than 1 weight-% of anti- solvent(s) is / are added and / or is / are present based on the total weight of the solvent including the antisolvent(s) being 100 weight-%. Cooling is done by any suitable method, for example, by letting the solvent obtained in step (e) stand under ambient conditions (1013 hPa and room temperature 20-25 °C), preferably with a cooling rate in the range of from 20 to 80 K / h, or by applying cooling means such as slow cooling, preferably in a crystallizer, preferably with a cooling rate in the range of from 3 to 25 K / h, in some preferred embodiments with a cooling rate in the range of from 3 to 60 K / h, fast cooling, preferably with a cooling rate > 100 K / h, dripping into a solvent, which has a temperature below 30 °C, wherein the solvent for dripping is the same or different as the solvent(s) of the solvent provided in step (a) but is in any case also a solvent selected from the group indicated above. In some embodiments, cooling is done with a cooling rate of < 3.0 °C / min, preferably < 1.5 °C / min, more preferably in the range of from 0.05 to 3.0 °C / min, more preferably in the range of from 0.13 to 3.0 °C / min, more preferably in the range of from 0.15 to 1.5 °C / min, more preferably in the range of from 0.15 to 1.0 °C / min.An "antisolvent” is a solvent having a solubility regarding the polyester < 1g / kg at a temperature in the range of from 20 to 25 °C.In some embodiments, the method comprises after (d), if a residue is present, and before step (e) (x.1) optionally contacting the residue comprising at least the third polymer of step (d) with solvent system, preferably at a temperature T2 ± 20°C, more preferably at a temperature in the range of T2 ± 10°C, as defined above in (d), followed by filtration, preferably heated filtration at a temperature T2 ± 20°C, more preferably at a temperature in the range of T2 ± 10°C, as defined above in (d), thereby obtaining a residue comprising at least the third polymer, which is further depleted of polyester and comprises the third polymer; and a solvent system, which contains further amount of the polyester;(x.2) optionally combining the solvent system, which contains the further amount of the polyester obtained in (x.1) with the solvent system, which is enriched in dissolved polyester, separated in (d).Preferably, the contacting in (x.1) is done in that, especially in cases where heated filtration is used in (d), the residue of the polymer blend obtained in (d) remains on the filter and is there brought into contact with solvent system, wherein the solvent system, which contains the remaining amount of the polyester obtained in (x.1), is separated thereof due to filtration.The solvent system used in (x.1) comprises NMP and optionally one or more solvent(s) selected from the group indicated above for the contacting in step (c). Preferably, the solvent system used in (x.1) is the same solvent system as240375W001- 14- the solvent system used in step (c). More preferably, in step (b) and in step (c) and in optional step (x.1 ), the same solvent comprising NMP is used.If step (x.1) and step (x.2) are conducted, cooling the solvent system in step (e) is preferably done based on the separated solvent system obtained in (d) or based on the combined solvent system obtained in (x.2).The method preferably further comprises(f) separating the precipitated polyester obtained in step (e) from the solvent, which is depleted in dissolved polyester, thereby obtaining a precipitated polyester and the solvent, which is depleted in dissolved polyester.The method preferably further comprises(g) optionally washing the precipitated polyester obtained in step (f);(h) drying the precipitated polyester obtained in step (f) or the washed precipitated polyester obtained in step (g).The separation in step (f) is done by methods and means known to the skilled person, especially solid-liquid separation methods such as filtration, for example, heated pressure filtration, sedimentation or centrifugation (see Hand- buch der mechanischen Fest-Fliissig-Trennung Taschenbuch - 29. April 2004 von Klaus Luckert (Herausgeber)).Washing in optional step (g) is preferably done with a solvent comprising one or more of the solvent(s) of the group defined above. In some embodiments, washing is done 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. In some embodiments, the washing in optional step (g) is done with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, NMP or a mixture of two or more of these solvents. Drying in step (h) is preferably done under one or more conditions selected from the group consisting of a pressure in the range of from 1 to 1013 mbar; a temperature in the range of from 50 to 210 °C, preferably in the range of from 60 to 180°C, more preferably in the range of from 80 to 160 °C; drying time in the range of from 30 minutes to 24 hours; drying in an atmosphere comprising nitrogen, preferably in an atmosphere having at least 90 volume-%, more preferably 95 volume-%, more preferably at least 98 volume-% nitrogen. Drying is done by one or more methods selected from the group consisting of contact drying, convection drying and radiation drying.In some preferred embodiments of the process, step (f), step (g) and step (h) are done at a pressure in the range of from 800 to 200,000 hPa.Preferably, the method comprises recycling solvent re-obtained from one or more step(s), preferably the separated solvent obtained in step (b.2), the washing solvent from step (b.3), the separated solvent of step (d), the separated solvent of step (f), and / or the washing solvent of step (g) at least partially to step (b) and / or step (c), optionally after one or more work-up step(s) such as distillation.240375W001- 15-The method preferably further comprises i) preparing a textile, a fiber, a packaging, a plastic, an automotive part, an electronic part from the polyester obtained from the method as described herein above, preferably part from the polyester obtained from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) as described herein above.2ndaspect - PolyesterIn a second aspect, the invention is directed to a polyester obtained or obtainable from the method according to any one of embodiments 1 to 21, preferably from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to the first aspect of the invention. The second aspect of the invention is also directed to a polyester prepared according to the method according to any one of embodiments 1 to 21, preferably from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to the first aspect of the invention. All details, embodiments and preferred embodiments described above with respect to the method of the first aspect of the invention equally apply to the second aspect of the invention.3rdaspect - UseIn a third aspect, the invention is directed to the use of the polyester of the second aspect of the invention for preparation of textile applications, fiber applications, packaging applications, plastic applications, automotive applications, electronic applications, preferably for the production of food packaging, beverage packaging, clothing, foot wear, wire, cable, wherein preferably in case that the polyester is selected from PBAT, PEF and PET, preferably PET, the polyester is used for textile applications, fiber applications, packaging applications, plastic applications, more preferably for the production of food packaging, beverage packaging, clothing and foot wear; wherein in case that the polyester is PBT, the polyester is used in textile applications, automotive applications, electronic applications, more preferably for the production of a wire and / or a cable. All details, embodiments and preferred embodiments described above with respect to the method of the first aspect of the invention or with respect to the polyester of the second aspect of the invention equally apply to the third aspect of the invention.4thaspect - Method for preparing a productA fourth aspect of the invention is directed to a method for preparing a product comprising(I) providing a polyester of the second aspect of the invention;(II) preparing a textile, a fiber, a packaging, a plastic, an automotive part, an electronic part from the polyester provided in step (I).240375W001- 16-All details, embodiments and preferred embodiments described above with respect to the method of the first aspect of the invention or with respect to the polyester of the second aspect of the invention or with respect to the use of the third aspect of the invention equally apply to the fourth aspect of the invention.According to a further aspect, the present invention relates to a method, preferably according to the method of the first aspect of the invention as described above, comprising the step of converting the polyester obtained or obtainable from the method according to the first aspect of the invention, preferably from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to the method of the first aspect of the invention or the second polymer obtained or obtainable from the method according to the first aspect of the invention, or a third polymer obtained or obtainable from the method according to the first aspect of the invention, or a chemical material obtainable by or obtained by the method according to the first aspect of the invention, to obtain a product PRF1.According to a still further aspect, the present invention relates to a product PRF1 , obtained or obtainable from the method of the above-described further aspect.Preferably, the product PRF1 is selected from: i) building block or monomer; or ii) polymer, preferably polymer A, polymer composition, preferably polymer composition A, or polymer product, preferably polymer product A; or iii) industrial use polymer, industrial use surfactant, descaling compound, industrial use biocide, industrial use solvent, industrial use dispersant, composition thereof or formulation thereof; or iv) agrochemical composition, agrochemical formulation auxiliary or agrochemically active ingredient; or v) active pharmaceutical ingredient or intermediate thereof, pharmaceutical excipient, animal feed additive, human food additive, dietary supplements, aroma chemical or aroma composition; or vi) aqueous polymer dispersion, preferably polyurethane or polyurethane - poly(meth)acrylate hybrid polymer dispersion, emulsion, binder for paper and fiber coatings, UV-curable acrylic polymer for hot melts and coatings polyisocyanates, hyperbranched polyester polyol, polymeric dispersant for inorganic binder compositions, unsaturated polyester polyol or 100% curable composition; or vii) cosmetic surfactant, emollient, wax, cosmetic polymer, UV filter, further cosmetic ingredient or composition or formulation thereof; or viii) polymer B, polymer composition B, coating composition, other functional composition, foil, molded body, coating or coated substrate.Regarding this process from which the product PRF1 , is obtained, it is preferred: that the content of the polyester obtained or obtainable from the method a according to the first aspect of the invention, or of the second polymer obtained or obtainable from the method according to the first aspect of the invention, or of the third polymer obtained or obtainable from the method according to the first aspect of the invention, or a240375W001- 17- chemical material obtainable by or obtained by the method according to the first aspect of the invention, in the product PRF1 is 1 weight-% or more, preferably 2 weight-% or more, more preferably 5 weight-% or more, more preferably 15 weight- % or more, more preferably 30 weight-% or more, more preferably 40 weight-% or more, more preferably 60 weight-% or more, more preferably 80 weight-% or more, more preferably 90 weight-% or more, more preferably 95 weight-% or more; and / or wherein the content of the polyester obtained or obtainable from the method according to the first aspect of the invention, or of the second polymer obtained or obtainable from the method according to the first aspect of the invention, or of the third polymer obtained or obtainable from the method according to the first aspect of the invention, or a chemical material obtainable by or obtained by the method according to the first aspect of the invention, in the product PRF1 is 100 weight-% or less, preferably 95 weight-% or less, more preferably 90 weight-% or less, more preferably 50 weight-% or less, more preferably 25 weight-% or less, more preferably 10 weight-% or less; and preferably wherein the 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 the International Sustainability and Carbon Certification (ISCC) standard.The publication Prior Art Disclosure; Issue 684; paragraphs

[1000] to

[8005] ; ISSN: 2198-4786; published: February 12, 2024 will be regarded as Reference RF1, which is incorporated herein by reference in its entirety. Preferably, the product PRF1 is a product as described in Reference RF1; paragraphs

[1000] to

[8005] , Preferably, the method described herein is further a method for the production of a product, preferably product PRF1 .The converting step to obtain the product PRF1 preferably comprises one or more step(s) as described below and can be performed by conventional methods well known to a person skilled in the art. The converting step preferably comprises one or more step(s) selected from: recycling, preferably depolymerizing, gasifying, pyrolyzing, and / or steam cracking; and / or purifying, preferably crystallizing, (solvent) extracting, distilling, evaporating, hydrotreating, absorbing, adsorbing and / or subjecting to ion exchanger; and / or assembling, preferably foaming, synthesizing, chemical conversion, chemically transforming, polymerizing and / or compounding; and / or forming, preferably foaming, extruding and / or molding; and / or finishing, preferably coating and / or smoothing.In addition, the one or more step(s) are described in detail in Reference RF1; paragraphs

[1000] to

[8005] ,The term "building block”, as used herein, comprises compounds, which are in a gaseous or liquid state under standard conditions of 0°C and 0.1 MPa. Building blocks are typically used in chemical industry to form secondary products, which provide a higher structural complexity and / or higher molecular weight than the building block on which the secondary product is based. The building block is preferably selected from the group consisting of hydrogen, car-240375W001- 18- bon monoxide, carbon dioxide, ethylene oxide, ethylene glycols, syngas comprising a mixture of hydrogen and carbon monoxide, alkanes, alkenes, alkynes and aromatic compounds. The alkanes, alkenes, alkynes and aromatic compounds comprise in particular 1 to 12 carbon atoms, respectively.The term "monomer”, as used herein, comprises molecules, which can react with each other to form polymer chains by polymerization. The monomer is preferably selected from the group consisting of (meth)acrylic acid, salts of (meth)acrylic acid; in particular sodium, potassium and zinc salts; (meth)acrolein and (meth)acrylates. (Methacrylates comprising 1 to 22 carbon atoms are preferred, in particular comprising 1 to 8 carbon atoms. The terms (meth)acrylic acid, (meth)acrolein or (meth)acrylate relate to acrylic acid, acrolein or acrylate and also to methacrylic acid, methacrolein or methacrylate, where applicable. Further, the monomer can be selected from hexamethylenediamine (HMD) and adipic acid.The building block can further be an intermediate compound. The term "intermediate compound”, as used herein, comprises organic reagents, which are applied for formation of compounds with higher molecular complexity. The intermediate compound can be selected for example from the group consisting of phosgene, polyisocyanates and propylene oxide. The polyisocyanates are in particular aromatic di- and polyisocyanates, preferably toluene diisocyanate (TDI) and / or diphenylmethane diisocyanate (MDI).The building block and the monomer and typical converting step(s) to obtain the building block or monomer are described in more detail in paragraphs

[1000] to

[1012] of Reference RF1.The term "polymer A”, as used herein, comprises thermoplastic, e.g., polyamide or thermoplastic polyurethane, thermoset, e.g., polyurethane, elastomer, e.g., polybutadiene, or a copolymer or a mixture thereof and is defined in more detail in paragraphs

[2001] to

[2007] of Reference RF1.The term "polymer composition A”, as used herein, comprises all compositions comprising a polymer as described above and one or more additive(s), e.g. reinforcement, colorant, modifier and / or flame retardant, and is defined in more detail in paragraph

[2008] of Reference RF1.The term "polymer product A”, as used herein, comprises any product comprising the polymer A and / or polymer composition A as described above and is defined in more detail in paragraphs

[2009] and

[2010] of Reference RF1.The step(s) to obtain the polymer, preferably polymer A, polymer composition, preferably polymer composition A or polymer product, preferably polymer product A is / are described in more detail in paragraph

[2011] of Reference RF1 .The term "industrial use polymer”, as used herein, comprises rheology, polycarboxylate, alkoxylated polyalkylenamine, alkoxylated polyalkylenimine, polyether-based, dye inhibition and soil release cleaning polymers defined in more detail in paragraphs

[3035] to

[3044] of Reference RF1. The term "industrial use surfactant”, as used herein, comprises non-ionic, anionic and amphoteric industrial use surfactants defined in more detail in paragraphs

[3008] to

[3034] of Reference RF1. The term "industrial use descaling compound”, as used herein, comprises non-phosphate based builders (NPB) and phosphonates (CoP) described in more detail in paragraphs

[3001] to

[3005] of Reference240375W001- 19-RF1. The term "industrial use biocide”, as used herein, refers to a chemical compound that kills microorganisms or inhibits their growth or reproduction defined in more detail in paragraphs

[3006] to

[3007] of Reference RF1. The term "industrial use solvent”, as used herein, comprises alkyl amides, alkyl lactamides, alkyl esters, lactate esters, alkyl diester, cyclic alkyl diester, cyclic carbonates, aromatic aldehydes and aromatic esters defined in more detail in paragraphs

[3045] to

[3055] of Reference RF1. The term "industrial use dispersant”, as used herein, comprises anionic and non-ionic industrial use dispersants defined in more detail in paragraphs

[3056] to

[3058] of Reference RF1 . The term "composition and / or formulation thereof' with reference to the industrial use polymers, industrial use surfactants, descaling compounds and / or industrial use biocides refers to industrial use compositions and / or institutional use products and / or fabric and home care products and / or personal care products defined in more detail in paragraph

[3059] of Reference RF1. The converting step(s) to obtain the industrial use polymer, industrial use surfactant, descaling compound and / or industrial use biocide are defined in more detail in paragraph

[3060] of Reference RF1 . The converting steps to obtain the industrial use composition or formulation of the industrial use polymer, industrial use surfactant, descaling compound and / or industrial use biocide are defined in more detail in paragraph

[3061] of Reference RF1.The term "agrochemical composition”, as used herein, typically relates to a composition comprising an agrochemi- cally active ingredient and at least one agrochemical formulation auxiliary. Examples of agrochemical compositions, active ingredients and auxiliaries are described in more detail in Reference RF1, paragraph

[4001] ,The agrochemical composition may take the form of any customary formulation. The agrochemical compositions are prepared in a known manner, e.g. described by Mollet and Grubemann, Formulation technology, Wiley VCH, Weinheim, 2001; or Knowles, New developments in crop protection product formulation, Agrow Reports DS243, T&F Informa, London, 2005. The converting step(s) to obtain the agrochemically active ingredients and auxiliaries may be conducted in analogy to the production step(s) of their analogues that are based on petrochemicals or other precursors that are not gained by recycling processes. In addition, conversion to compounds mentioned in sections "Polymer” and "Cosmetic surfactant, emollient, wax, cosmetic polymer, UV filter, further cosmetic ingredient or compositions or formulations thereof' may be performed as described in these sections as well as the respective paragraphs in Reference RF1.The term active pharmaceutical ingredients and / or intermediates thereof, as used herein, comprises substances that provide pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of the body. Intermediates thereof are isolated products that are generated during a multi-step route of synthesis of an active pharmaceutical ingredient. The term pharmaceutical excipients, as used herein, comprises compounds or compound mixtures used in compositions for various pharmaceutical applications, which are not substantially pharmaceutically active on itself. Active pharmaceutical ingredients and / or intermediates thereof and pharmaceutical excipients are defined in more detail in paragraph

[5001] of Reference RF1.240375W001- 20-The converting step(s) to obtain the active pharmaceutical ingredients and / or intermediates thereof and pharmaceutical excipients may comprise one or more synthesis steps and can be performed by conventional synthesis and techniques well known to a person skilled in the art.The terms animal feed additives, human food additives, dietary supplements, as used herein, comprises Vitamins, Pro-Vitamins and active metabolites thereof including intermediates and precursors, especially Vitamin A, B, E, D, K and esters thereof, like acetate, propionate, palmitate esters or alcohols thereof like retinol or salts thereof and any combinations thereof; Tetraterpenes, especially isoprenoids like carotenoids and xanthophylls including their intermediates and precursors as well as mixtures and derivates thereof, especially beta carotene, Canthaxanthin, Citranax- anthin, Astaxanthin, Zeaxanthin, Lutein, Lycopene, Apo-carotenoids, and any combinations thereof; organic acids, especially formic acid, propionic acid and salts thereof, such as sodium, calcium or ammonium salts, and any combinations thereof, such as but not limited to mixtures of formic acid and sodium formiate, propionic acid and ammonium propionate, formic acid and propionic acid, formic acid and sodium formiate and propionic acid, propionic acid and sodium propionate and formic acid and sodium formiate; glycerides of carboxylic acids and short and medium chain fatty acids, conjugated linoleic acids, such as omega-6 fatty acid (C18:2) methyl ester and 1 ,2-propandiol and beverage stabilizers, such as polyvinylpyrrolidone-polymer or polyvinylimidazole / polyvinylpyrrolidone-copolymer. Animal feed additives, human food additives and dietary supplements are defined in more detail in paragraph

[5002] of Reference RF1.The converting step(s) to obtain the animal feed additives, human food additives, dietary supplements may comprise one or more synthesis steps and can be performed by conventional synthesis and techniques well known to a person skilled in the art.The terms aroma chemical and aroma composition as used herein, comprise a volatile organic substance with a molecular weight between 70-250 g / mol comprising a functional group with a carbon skeleton of C5-C16 carbon atoms comprising linear, branched, cyclic, for example with a ring size of C5-C18, bicyclic or tricyclic aliphatic chains and but not necessarily one or more unsaturated structural elements like double bonds, triple bonds, aromatics or heteroaromatics and preferably the one or more additional functional groups are selected from alcohol, ether, ester, ketone, aldehyde, acetal, carboxylic acid, nitrile, thiol, amine. In one aspect, the aroma chemical is a terpene-based aroma chemical, for example selected from monoterpenes and monoterpenoids, sesquiterpenes and sesquiterpenoids, diterpenes, triterpenes or tetraterpenes. Aroma chemicals can be combined with further aroma chemicals to give an aroma composition. Aroma chemicals and aroma compositions are defined in more detail in paragraph

[5003] of Reference RF1.The converting step(s) to obtain the aroma chemical and aroma composition may comprise one or more synthesis steps and can be performed by conventional synthesis and techniques well known to a person skilled in the art.The term "aqueous polymer dispersion”, as used herein, comprises aqueous composition(s) comprising dispersed polymer(s) and is defined in more detail in the section

[6001] entitled "aqueous polymer dispersion” of Reference240375W001- 21-RF1. The dispersed polymer(s) may be selected from acrylic emulsion polymer(s), styrene acrylic emulsion poly- mer(s), styrene butadiene dispersion(s), aqueous dispersion(s) comprising composite particles, acrylate alkyd hybrid dispersion(s), polyurethane(s) (including UV-curable polyurethanes) and polyurethane - poly(meth)acrylate hybrid polymer(s). The term "emulsion polymer”, as used herein, comprises polymer(s) made by free-radical emulsion polymerization. Aqueous polyurethane dispersion(s) are defined in more detail in the section

[6002] entitled "Polyurethane dispersions” of Reference RF1. UV-curable polyurethane(s) is / are defined in more detail in the section

[6017] of Reference RF1. Polyurethane - poly(meth)acrylate hybrid polymer(s) is / are defined in more detail in the section

[6016] of Reference RF1 .The term "polymeric dispersant”, as used herein, comprises preferably polymer(s) comprising polyether side chain, in particular polycarboxylate ether polymer(s) and polycondensation product(s) defined in more detail in paragraph

[6020] entitled "Polymeric dispersant” of Reference RF1 .The converting (polymerization) step(s) to obtain the aqueous polymer dispersion(s) comprising emulsion polymer(s) is / are defined in more detail in the section

[6003] entitled "Emulsion polymerization” of Reference RF1.The converting (polymerization) step(s) to obtain the aqueous polyurethane dispersion(s) is / are defined in more detail in the section

[6014] entitled "Process for the preparation of aqueous polyurethane dispersions” and section

[6017] entitled "Aqueous UV-curable polyurethane dispersions, their preparation and use and compositions containing them” of Reference RF1 .Composition(s) and uses of aqueous polymer dispersion(s) and of polymeric dispersant(s) are defined in more detail in the following sections of Reference RF1 : section

[6004] entitled "Uses of aqueous polymer dispersions”, section

[6005] entitled "Binders for architectural and construction coatings” section

[6006] entitled "Binders for paper coating” section

[6007] entitled "Binders for fiber bonding” section

[6008] entitled "Adhesive polymers and adhesive compositions” section

[6015] entitled "Aqueous polyurethane dispersions suitable for use in coating compositions” section

[6016] entitled "Aqueous polyurethane - poly(meth)acrylate hybride polymer dispersions suitable for use in coating compositions” section

[6017] entitled "Aqueous UV-curable polyurethane dispersions, their preparation and use and compositions containing them” section

[6018] entitled "Inorganic binder compositions comprising polymeric dispersants and their use”

[6019] 100% curable coating compositionsUV-crosslinkable poly(meth)acrylate(s) and its / their uses are defined in more detail in section

[6009] entitled "UV- crossli nkable poly(meth)acrylates for use in UV-curable solvent-free hotmelt adhesives and their use for making pressure-sensitive self-adhesive articles” of Reference RF1.240375W001- 22-Polyisocyanate(s), composition(s) comprising them and their uses are defined in more detail in section

[6010] entitled "Polyisocyanates” of Reference RF1.Hyperbranched polyester polyol(s) and its / their uses are defined in more detail in section

[6011] entitled "Organic solvent based hyperbranched polyester polyols suitable for use in coating compositions” of Reference RF1. The converting step(s) to obtain the hyperbranched polyester polyols is / are defined in more detail in the section

[6012] entitled "Preparation of organic solvent based hyperbranched polyester polyols” of Reference RF1. Coating compositions) comprising hyperbranched polyester polyol(s), polyisocyanate(s) and additive(s) and substrate(s) coated therewith are defined in more detail in section

[6013] entitled "Organic solvent based two component coating compositions comprising hyperbranched polyester polyols and polyisocyanates” of Reference RF1.Unsaturated polyester polyol(s), solvent-based coating composition(s) comprising said unsaturated polyester pol- yol(s) and substrate(s) for coating with said coating composition(s) are defined in more detail in section

[6018] entitled "Organic solvent based coating composition comprising unsaturated polyester polyols” of Reference RF1. 100% curable coating composition(s) is / are defined in more detail in section

[6019] of Reference RF1.Polymeric dispersant(s) for inorganic binder compositions is / are defined in more detail in section

[6020] of Reference RF1. The inorganic binder composition(s) comprising the polymeric dispersants and their use are defined in more detail in section

[6021] of Reference RF1. The converting step(s) to obtain the polymeric dispersant(s) are defined in more detail in section

[6020] of Reference RF1 . The term "inorganic binder composition” comprising the polymeric dispersant(s), as used herein, comprises preferably in particular hydraulically setting compositions and compositions comprising calcium sulfate and is defined in more detail in section

[6021] of Reference RF1 entitled "Inorganic binder compositions comprising the polymeric dispersant and their use”. Specific building material formulation(s) comprising polymeric dispersant(s) or building product(s) produced by a building material formulation comprising a polymeric dispersant are disclosed in more detail in section

[6021] of Reference RF1.The term "cosmetic surfactant”, as used herein, comprises non-ionic, anionic, cationic and amphoteric surfactants and is defined in more detail in paragraph

[7002] of Reference RF1. The term "emollient”, as used herein, refers to a chemical compound used for protecting, moisturizing, and / or lubricating the skin and is defined in more detail in paragraph

[7003] of Reference RF1 . The term "wax”, as used herein, comprises pearlizers and opacifiers and is defined in more detail in paragraph

[7004] of Reference RF1. The term "cosmetic polymer”, as used herein, comprises any polymer that can be used as an ingredient in a cosmetic formulation and is defined in more detail in paragraph

[7005] of Reference RF1 . The term "UV filter”, as used herein, refers to a chemical compound that blocks or absorbs ultraviolet light and is defined in more detail in paragraph

[7006] of Reference RF1. The term "further cosmetic ingredient”, as used herein, comprises any ingredient suitable for making a cosmetic formulation. Several sources disclose cosmetically acceptable ingredients. E. g. the database Cosing on the internet pages of the European Commission discloses cosmetic ingredients and the International Cosmetic Ingredient Dictionary and Handbook, edited by the Personal Care Products Council (PCPC), discloses cosmetic ingredients. The term "composition and / or formulation thereof' with reference to the cosmetic surfactant, emollient, wax, cosmetic polymer, UV filter and / or further cosmetic240375W001- 23- ingredient refers to personal care and / or cosmetic compositions or formulations defined in more detail in paragraph

[7007] of Reference RF1. The converting step(s) to obtain the cosmetic surfactant, emollient, wax, cosmetic polymer, UV filter or further cosmetic ingredient is / are defined in more detail in paragraph

[7008] of Reference RF1 .The terms "polymer B”, "polymer composition B”, "coating composition”, "other functional composition”, "foil”, "molded body”, "coating” and "coated substrate” are well known to the person skilled in the art and are defined in more detail from paragraph

[8000] to

[8005] of Reference RF1.The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The method of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The method of any one of embodiments 1, 2, 3 and 4". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.1 . A method for separating a polymer blend, wherein the polymer blend comprises(I) a polyester and(ii) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and 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 comprising 1 -methylpyrrolidin-2-one (NMP);(b) contacting the polymer blend with the solvent comprising NMP at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising NMP, which is enriched in dissolved optional second polymer, in optional colorant and in optional additive or a part thereof; and a residue of the polymer blend, which is depleted of optional second polymer, of optional colorant and of optional additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof; and / or(c) contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) with a solvent comprising NMP at a temperature T2 in the range of from > 150 to < 160°C, thereby obtaining a solvent, which comprises NMP and which is enriched in dissolved polyester compared to the solvent provided in step (a) and comprises optionally at least a part of the additive, and optionally a residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof.240375W001- 24-2. The method for separating a polymer blend according to embodiment 1, wherein the polymer blend comprises(I) a polyester and(II) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and 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 comprising 1 -methylpyrrolidin-2-one;(b) optionally contacting the polymer blend with the solvent comprising 1 -methylpyrrolidin-2-one at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising 1 -methyl pyrrol I- din-2-one, which is enriched in dissolved optional second polymer, in optional colorant and in optional additive or a part thereof; and a residue of the polymer blend, which is depleted of optional second polymer, of optional colorant and of optional additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof; and(c) contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) with a solvent comprising 1 -methylpyrrolidin-2-one at a temperature T2 in the range of from > 150 to < 160°C, thereby obtaining a solvent, which comprises 1 -methylpyrrolidin-2-one and which is enriched in dissolved polyester compared to the solvent provided in step (a) and comprises optionally at least a part of the additive, and optionally a residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof.3. The method of embodiment 1 or 2, wherein T 1 according to step (b) is in the range of from 120 to < 140°C, more preferably in the range of from 120 to < 135°C.4. The method of any one of embodiments 1 to 3, wherein T2 according to step (c) is in the range of from 151 to 159°C.5. The method of any one of embodiments 1 to 4, wherein the solvent comprises NMP and optionally one or more solvent(s) selected from the group consisting of water and organic solvents having a log Kow in the range of from -1 .6 to +1 .6, more preferably selected from the group consisting of water, C5 to C12 alkane, aliphatic C1 to C10 alcohol, C3 to C10 ketone, C2 to C10 cyclic ketone, HO-[C1 to C10 alkyl-O-]n-H, with n being an integer in the range of from 2 to 1000, C1 to C10 alkyl-O-C3 to C10 alkyl ether, C3 to C10 cyclic ether, optionally substituted with one or more C1 to C6 alkyl group(s), C6 to C10 aromatic hydrocarbon, optionally substituted with one or more C1 to C6 alkyl group(s), C2 to C10 aliphatic ester, C8 to C11 aromatic ester, C5 to C10 cyclic carboxylic ester (lactone), C3 to C12 amide, preferably R1R2N-C(=O)-R3, wherein R1, R2are independently a C1 to C4 alkyl group and R3is selected from the group consisting of C1 to C9 alkyl group, C1 to C10 ester group and C1 to C6 ether group, unsubstituted C3 to C6 lactame, C3 to C4 or C6 lac- tame substituted with one or more substituent selected from C1 to C6 alkyl group, C1 to C6 ester group and240375W001- 25-C1 to C6 ether group, and C5 imidazolidine, optionally substituted with one or more C1 to C6 alkyl group(s), C5 to C7 imidazolidone, optionally substituted with one or more C1 to C6 alkyl group(s), wherein preferably at least 1 weight-%, more preferably at least 5 weight-%, more preferably at least 10 weight-%, more preferably at least 20 weight-%, more preferably at least 30 weight-%, more preferably at least 40 weight-%, more preferably at least 50 weight-%, more preferably at least 60 weight-%, more preferably at least 70 weight-%, more preferably at least 80 weight-%, more preferably at least 90 weight-%, more preferably at least 95 weight-% of the solvent consists of NMP, based on the total weight of the solvent being 100 weight-%.6. The method of any one of embodiments 1 to 5, wherein in step (b) and step (c) the same solvent comprising NMP is used.7. The method of any one of embodiments 1 to 6, wherein the polyester is based on 1,4-butanediol or 1,2- ethandiol, more preferably the polyester according to (I) is selected from the group consisting of a polymer based on 1,4-butanediol and terephthalic acid (polybutylene terephthalate, PBT), a polymer based on 1,2- ethanediol and terephthalic acid (polyethylene terephthalate, PET), a co-polymer of 1,4-butanediol, adipic acid and terephthalic acid (polybutylenadipat-terephthalat, PBAT), a polymer of 1 ,2-ethanediol and 2,5-furandicar- boxylic acid (polyethylene furanoate, PEF) and mixtures of two or more of these (co)polymers, more preferably, the polyester comprises at least PET or PBT, more preferably the polyester is PET or PBT or a mixture of PET and PBT.8. The method of any one of embodiments 1 to 7, 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 a copolymer of PU and PEG and / or pTHF, more preferably spandex (copolymer of PU and PEG or of PU and pTHF).9. The method of any one of embodiments 1 to 8, wherein the colorant is selected from the group consisting of dye and optical brightener and mixtures of dye and optical brightener.10. The method of any one of embodiments 1 to 9, wherein the additive is selected from the group consisting of softener, water repellent, flame retardant, UV filter, plasticizer, filler and mixtures of two or more thereof.11. The method of any one of embodiments 1 to 10, wherein step (b) and / or step (c) are done in a gaseous atmosphere comprising at least one inert gas, preferably in a gaseous atmosphere comprising nitrogen.12. The method of any one of embodiments 1 to 11, wherein step (b) and / or step (c) are done at a pressure in the range of from 800 to 1200 hPa, preferably in the range of from 900 to 1100 hPa, more preferably in the range of from 1000 to 1100 hPa or at a pressure pressure in the range of from 1013 to 200,000 hPa, preferably in the range of from 1013 to 100,000 hPa.240375W001- 26-13. The method of any one of embodiments 1 to 12, wherein the mass based ratio polymer blend : solvent in step (b) and / or in step (c) is in the range of 1 :1 to 1 :100, preferably in the range of from 1 :1 to 1:20.14. The method of any one of embodiments 1 to 13, wherein step (b) comprises:(b.1) contacting the polymer blend with the solvent comprising NMP at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising NMP, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof; and a residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof;(b.2) separating the solvent, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof, and the residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof obtained in step (b.1 ), preferably by a physical separation method, thereby obtaining a separated solvent, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof compared to the solvent provided in step (a) and the residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof.15. The method of any one of embodiments 1 to 14, wherein step (b) further comprises:(b.3) washing the separated residue of the polymer blend obtained in step (b.2) at least once with a washing solvent comprising NMP and optionally one or more solvent(s) selected from the group indicated above, thereby obtaining a washed residue;(b.4) optionally drying the washed residue obtained in step (b.3).16. The method of any one of embodiments 1 to 15, wherein the third polymer is selected from the group consisting of polyolefins, preferably polyethylene (PE) and polypropylene (PP), polyamide (PA), natural polymer, preferably wool, cotton or viscose, mixtures of two or more of these polymers and copolymers of two or more of these polymers, wherein the third polymer is preferably selected from PA, wool, cotton, viscose and mixtures of two or more of these polymers.17. The method of any one of embodiments 1 to 16, wherein the polymer blend comprises at least a third polymer, the method comprising d) separation of the solvent system, which is enriched in dissolved polyester obtained in step (c) from the residue obtained in step (c), thereby obtaining a solvent enriched in dissolved polyester, which is free240375W001- 27- of third polymer, and a residue comprising at least the third polymer, wherein the separation is done by heated solid-liquid separation, preferably at a temperature in the range of T ± 20°C, more preferably at a temperature in the range of T ± 10°C.18. The method of any one of embodiments 1 to 17 further comprising(e) optionally after heated filtration according to step (d), cooling the solvent obtained in step (c) or in step (d), which is enriched in dissolved polyester compared to the solvent provided in (a), to a temperature below T2 preferably below 150°C, more preferably below 140°C, more preferably below 120°C; thereby obtaining a precipitated polyester and a solvent, which is depleted in dissolved polyester.19. The method of embodiment 18, wherein cooling in step (e) is done without addition of antisolvents.20. The method of any one of embodiments 1 to 19 comprising(f) separating the precipitated polyester obtained in step (e) from the solvent, which is depleted in dissolved polyester, thereby obtaining a precipitated polyester and the solvent, which is depleted in dissolved polyester.21 . The method of any one of embodiments 1 to 20 comprising(g) optionally washing the precipitated polyester obtained in step (f);(h) drying the precipitated polyester obtained in step (f) or the washed precipitated polyester obtained in step (g).22. The method for separating a polymer blend of any one of embodiments 1 to 21 comprising recycling solvent re-obtained from one or more step(s), preferably the separated solvent obtained in step (b.2), the washing solvent from step (b.3), the separated solvent of step (d), the separated solvent of step (f), and / or the washing solvent of step (g) at least partially to step (b) and / or step (c), optionally after one or more work-up step(s).23. The method for separating a polymer blend of any one of embodiments 1 to 22, comprisingI) preparing a textile, a fiber, a packaging, a plastic, an automotive part, an electronic part from the polyester obtained from the method according to any one of embodiments 1 to 22, preferably part from the polyester obtained from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to any one of embodiments 1 to 22.24. A polyester obtained or obtainable from the method according to any one of embodiments 1 to 22, preferably from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to any one of embodiments 1 to 22.240375W001- 28-25. Use of the polyester of embodiment 24 for preparation of textile applications, fiber applications, packaging applications, plastic applications, automotive applications, electronic applications, preferably for the production of food packaging, beverage packaging, clothing, foot wear, wire, cable, wherein preferably in case that the polyester is selected from PBAT, PEF and PET, preferably PET, the polyester is used for textile applications, fiber applications, packaging applications, plastic applications, more preferably for the production of food packaging, beverage packaging, clothing and foot wear; wherein in case that the polyester is PBT, the polyester is used in textile applications, automotive applications, electronic applications, more preferably for the production of a wire and / or a cable.26. A method for preparing a product comprising(I) providing a polyester of embodiment 24;(II) preparing a textile, a fiber, a packaging, a plastic, an automotive part, an electronic part from the polyester provided in (I).27. Method, preferably according to any one of embodiments 1 to 22, comprising the step of converting the polyester obtained or obtainable from the method according to any one of embodiments 1 to 22, preferably from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to any one of embodiments 1 to 22 or the second polymer obtained or obtainable from the method according to any one of embodiments 1 to 22, or a third polymer obtained or obtainable from the method according to any one of embodiments 1 to 22, or a chemical material obtainable by or obtained by the method according to any one of any one of embodiments 1 to 22, to obtain a product PRF1 .28. Method according to embodiment 27, wherein the product PRF1 is selected from: i) building block or monomer; or ii) polymer, preferably polymer A, polymer composition, preferably polymer composition A, or polymer product, preferably polymer product A; or iii) industrial use polymer, industrial use surfactant, descaling compound, industrial use biocide, industrial use solvent, industrial use dispersant, composition thereof or formulation thereof; or iv) agrochemical composition, agrochemical formulation auxiliary or agrochemically active ingredient; or v) active pharmaceutical ingredient or intermediate thereof, pharmaceutical excipient, animal feed additive, human food additive, dietary supplements, aroma chemical or aroma composition; or vi) aqueous polymer dispersion, preferably polyurethane or polyurethane - poly(meth)acrylate hybrid polymer dispersion, emulsion, binder for paper and fiber coatings, UV-curable acrylic polymer for hot melts and coatings polyisocyanates, hyperbranched polyester polyol, polymeric dispersant for inorganic binder compositions, unsaturated polyester polyol or 100% curable composition; or vii) cosmetic surfactant, emollient, wax, cosmetic polymer, UV filter, further cosmetic ingredient or composition or formulation thereof; or240375W001- 29- viii) polymer B, polymer composition B, coating composition, other functional composition, foil, molded body, coating or coated substrate.29. Method according to embodiment 27 or 28, wherein the content of the polyester obtained or obtainable from the method according to any one of embodiments 1 to 22, or of the second polymer obtained or obtainable from the method according to any one of embodiments 1 to 22, or of the third polymer obtained or obtainable from the method according to any one of embodiments 1 to 22, or a chemical material obtainable by or obtained by the method according to any one of any one of embodiments 1 to 22, in the product PRF1 is 1 weight-% or more, preferably 2 weight-% or more, more preferably 5 weight-% or more, more preferably 15 weight-% or more, more preferably 30 weight-% or more, more preferably 40 weight-% or more, more preferably 60 weight-% or more, more preferably 80 weight-% or more, more preferably 90 weight-% or more, more preferably 95 weight-% or more; and / or wherein the content of the polyester obtained or obtainable from the method according to any one of embodiments 1 to 22, or of the second polymer obtained or obtainable from the method according to any one of embodiments 1 to 22, or of the third polymer obtained or obtainable from the method according to any one of embodiments 1 to 22, or a chemical material obtainable by or obtained by the method according to any one of any one of embodiments 1 to 22, in the product PRF1 is 100 weight-% or less, preferably 95 weight-% or less, more preferably 90 weight-% or less, more preferably 50 weight-% or less, more preferably 25 weight-% or less, more preferably 10 weight-% or less; and preferably wherein the 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 the International Sustainability and Carbon Certification (ISCC) standard.30. A product PRF1 , obtained or obtainable from the method of embodiment 29.The present invention is further illustrated by the following reference examples, comparative examples, and examples.ExamplesAnalytic methodsCIE-LAB:L*a*b* values were determined in that the samples were measured using an integrating sphere and UVA / IS-remis- sion spectra (with a wavelength area of 400-700 nm) were obtained. The data of these spectra were analyzed by the software OptLab-SPX using 2° standard observer and the standard light type C. The OptLab-SPX software calculates the L*a*b*-values based on DIN 5033 and DIN EN ISO 11664-1.6 from the years 2007-2014.240375W001- 30-Gel-Permeation Chromatography (GPC):Sample preparation:7.5 mg sample was dissolved in 5 ml eluent (hexafluorisopropanol + 0.05 weight-% trifluoro potassium acetate) over night. All sample solutions were filtered by a Millipore Millex FG (0.2 m) filtered prior to injection. Sealed sample vials were placed into the auto sampler.Experimental conditions:An Agilent 1100 HPLC system, consisting of an isocratic pump, vacuum degasser, auto sampler and a column oven (40°C) was used. Furthermore, the Agilent system contained as detectors a Differential Refractive Index (DRI) and a variable Ultra Violet (UVW) Detector. Data acquisition and data processing of conventionally SEC data were done by WinGPC Unichrom, of PSS (Polymer Standard Services). A combination of a PL-HFIP guard (7.5 x 50 mm) column and 2 PL-HFIP Gel columns (7.5 x 300 mm, 9pi) of Agilent were put in series. As an eluent, hexafluorisopropanol + 0.05 weight-% trifluoro potassium acetate was used as a flow rate of 1 ml / min. Of each sample solution 50pi I was injected. The calibration was obtained by narrow molar mass distributed PMMA standards (Polymer Standard Services) having a molar mass range of M= 800 till M = 2.200.000 g / mol. Molar masses outside this range were extrapolated.Infrared:Fourier Transformed Infrared-attenuated total reflection(FTIR-ATR) spectra were obtained by FTIR spectrometers equipped with ATR units (Thermo Nicolet IS50 + diamond ATR unit).For measurement the samples were placed directly onto the ATR crystal without further preparation and were fixed with the unit's stamp. All measurements were performed at room temperature (25 °C) using 32 scans and a resolution of 4 cm-1.Chemicals240375W001- 31-GeneralAll samples of PET comprising polymeric material were analysed before treatment and after the final drying step in that number average molecular weight Mn, mass average molecular weight Mw, dispersity Mw / Mn were determined based on GPC and / or L*a*b* values were determined.The used solvent was optionally distilled and could be re-used as virgin NMP.Reference Example 1 : PET recycling based on dissolutionPolymeric material comprising PET (in any colour) was cut / shredded into pieces and placed in a reaction vessel (e.g. flask, tube, reaction vessel). The solvent was added (in mass-based ratio solvent : polymeric material 100:1 to 1 :1, preferred 10:1-1 :1) and the mixture was heated by use of a suitable heating system (e.g. oil bath, heating blocks, mini-plant vessels) to a specific temperature under inert gas atmosphere, wherein PET was fully dissolved upon visual inspection (1-30 min). While heating and dissolving PET, in case that NMP was used as solvent, a nitrogen stream flows above the surface. The mixture was optionally filtered while PET was still dissolved. Thereafter the reaction mixture or filtrate was allowed to cool-down while the PET precipitated. The precipitate was filtrated and optionally washed with a small amount of the solvent. For an easy removal of said solvent and a faster drying process of the re-obtained PET powder, small amounts of acetone can optionally be used in a second washing step. The thus obtained solid was dried (for example in a vacuum compartment dryer).Reference Example 2: PET recycling based on discolorationColored and optionally elastic fiber containing polymeric material comprising PET (in any colour) was cut / shredded into pieces and placed in a reaction vessel (e.g. flask, tube, reaction vessel). The solvent was added (in mass-based ratio solvent : polymeric material 100:1 to 1 :1, preferred 10:1-1 :1) and the mixture was heated by use of a suitable heating system (e.g. oil bath, heating blocks, mini-plant vessels) to a specific temperature. While heating and discoloration, in case that NMP was used as solvent, a nitrogen stream flows above the surface. After 0.5-8 h the mixture was filtered, whereby the solvent enriched in colorant and color-depleted polymeric material pieces were obtained and the color-depleted polymeric material pieces were washed with a small amount of said solvent. For an easy removal of said solvent and a faster drying process of the color-depleted polymeric material pieces, small amounts of acetone can optionally be used in a second washing step. The thus obtained polymeric material pieces were dried (for example in a vacuum compartment dryer).Reference Example 3: Separation of Spandex and PET240375W001- 32-Colored polymeric material (in any colour) comprising PET and Spandex was cut / shredded into pieces and placed in a reaction vessel (e.g. flask, tube, reaction vessel). Solvent was added (in mass-based ratio solventpolymeric material 1:1 to 100:1, preferred 10:1-1 :1) and the mixture was heated by use of a suitable heating system (e.g. oil bath, heating blocks, mini-plant vessels) to specific temperature so that a mixture was obtained, wherein Spandex was fully dissolved and PET remained unsolved. While heating and dissolving of Spandex, in case that NMP was used as solvent, a nitrogen, stream flows above the surface. After 0.1-4 h the mixture was filtered, whereby solvent enriched in Spandex and colorant and color-depleted PET pieces were obtained and the polymeric material pieces were washed with a small amount of solvent. For an easy removal of NMP and a faster drying process of the Spandex-free discolored PET pieces, small amounts of acetone were optionally used in a second washing step. The thus obtained polymeric material pieces were dried (for example in a vacuum compartment dryer).Reference Example 4: Separation of PET from Cotton and / or PAColored polymeric material (in any colour) comprising PET and Cotton and / or PA was cut / shredded into pieces and placed in a reaction vessel (e.g. flask, tube, reaction vessel). Solvent was added (in mass-based ratio solventpoly- meric material 1 :1 to 100:1, preferred 10:1-1 :1) and the mixture was heated by use of a suitable heating system (e.g. oil bath, heating blocks, mini-plant vessels) to a specific temperature so that a mixture was obtained, wherein PET was fully dissolved and dissolvable parts of filler, if present, were dissolved, but solid particles remained in the mixture; the mixture was maintained at the specific temperature for a time in the range of from 1 to 60 min. While heating and dissolving PET, in case that NMP was used as solvent, a nitrogen stream flows above the surface. The mixture was filtered (e.g. heated pressure filtration), whereby a filter cake with undissolved polymeric materials (Cotton and / or PA and undissolvable parts of filler, if present) and a filtrate with PET were obtained. The filter cake was optionally further washed with a small amount of hot solvent. As the filtrate started to cool-down the PET precipitated. The precipitate was filtrated, wherein the part of filler, if present, which was soluble in solvent but did not precipitate during cooling, was removed with the filtrate. The precipitated PET was optionally washed with a small amount of solvent. For an easy removal of solvent and a faster drying process of the re-obtained color-depleted PET powder, small amounts of acetone were optionally used in a second washing step. The filter cake was also washed with a small amount of solvent. For an easy removal of solvent and a faster drying process of the cotton pieces or of PA pieces, small amounts of acetone were optionally used in a second washing step. The thus obtained polymeric materials (re-obtained PET and undissolved cotton or PA) were dried (for example in a vacuum compartment dryer).Example 1 : PET recycling by dissolution with NMPAn initial test for the dissolution of PET in NMP showed that PET already dissolves at 150 °C.240375W001- 33-Therefore, experiments were conducted with a polymeric material comprising PET of white appearance according to the procedure described in Reference Example 1 using NMP as solvent (both with a concentration of 1 :10 (textile / solvent)) at a specific temperature of 152°C (Example 1a), 155°C (Example 1b), and 158 °C (Example 1c) respectively.The finally obtained solid PET product of both experiments was analyzed with GPC and compared with the starting material used, wherein the results are summarized in Table 1.Comparative Example 1 : PET recycling by dissolution with NMP at T < 150°C and > 160°CFour comparative experiments were conducted with a polymeric material comprising PET of white appearance according to the procedure described in Reference Example 1 using NMP as solvent (both with a concentration of 1:10 (textile / solvent)) at a specific temperature of 145°C (Comparative Example 1a), 162°C (Comparative Example 1b), , 170°C (Comparative Example 1c), and 185 °C (Comparative Example 1d) respectively.The finally obtained solid PET product of both experiments was analyzed with GPC and compared with the starting material used, wherein the results are summarized in Table 1.Comparative Example 2: PET recycling by dissolution using GVL as solventTwo comparative examples were conducted according to the procedure described in Reference Example 1 (both with a concentration of 1 :10 (textile / solvent)) with a polymeric material comprising PET at a specific temperature of 150°C (‘Comparative Example 2a) and at 185 °C (Comparative Example 2b) respectively, wherein GVL was used as solvent instead of NMP. It was found that at 150°C, GVL was unable to dissolve the PET, and the dissolution with GVL worked only at 185°C. The results are summarized in Table 1.Table 1GPC data from the finally obtained solid PET of Examples 1a to 1c and Comparative Examples 1a to 1d and 2a, 2b after dissolution and precipitation etc..240375W001- 34-+PET did not completely dissolve in NMP at a temperature of 145°C - only less than 50 weight-% could be dissolvec(3.2 g of 10 g subjected to dissolution)* PET did not dissolve in GVL at a temperature of 150°CIt was found that first, NMP was able to dissolve PET at a significantly lower temperature instead of GVL, which required a temperature of 185°C for PET dissolution. Using NMP at a temperature < 150°C (145°C) had a negative impact on at least yield, as not all, moreover less than 50 weight-%, PET could be dissolved. Using NMP at a temperature in the range of from > 150°C to < 160°C resulted in a re-obtained PET having only a slight decrease regarding the mass average molecular weight Mw and an increase in the number average molecular weight Mn compared to the starting material. Using NMP at 165°C or at 185°C resulted in a re-obtained PET having a strongly impaired polymeric structure shown especially by a significant decrease of the mass average molecular weight Mw. Furthermore, it was shown that for using NMP at temperatures > 160°C, the re-obtained solvent NMP was strongly colored (orange) compared to using NMP at 152°C, where only a light coloring of the re-obtained solvent NMP (light yellow) was seen upon visual inspection.Example 2: Discoloration with NMPSince NMP dissolves PET at already 150 °C, a discoloration of a black polymeric material comprising PET was done according to the procedure of Reference Example 2 at a specific temperature of 120°C (Example 2a), 130°C (Example 2b) and 140°C (Example 2c) respectively. The results are summarized in Table 2.Comparative Example 3: Discoloration with GVL240375W001- 35-A discoloration of a black polymeric material comprising PET was done according to the procedure of Reference Example 2 at a specific temperature of 150 °C using GVL instead of NMP as solvent. The results are summarized in Table 2.Table 2Discoloration results of Examples 2a to 2b and Comparative Example 3It was found that NMP already at 120°C was able to decolorize PET so that a PET with an almost white appearance could be obtained, wherein a discoloration using NMP at 120°C resulted in a re-obtained PET having an increased mass average molecular weight Mw and an increased number average molecular weight Mn. Using GVL for comparison gave comparable results for discoloration, but required significantly more energy (150°C for GVL required).Example 3: Separation of PET and cotton using NMPColored polymeric material comprising PET and Cotton was treated according to the procedure described in Reference Example 4 using NMP as solvent (both with a concentration of 1 :10 (textile / solvent)) at a specific temperature of 150 °C. The re-obtained PET powder and cotton residue, each after drying, were investigated by infrared (IR), wherein the IR spectra were compared with reference IR spectra of pure PET and of pure cotton respectively. It was240375W001- 36- found that the re-obtained cotton was free of PET (Fig. 1) and the re-obtained PET (Fig. 2) was free of cotton respectively.Short description of the FiguresFig. 1 shows IR spectra of re-obtained cotton (measured twice) obtained according to Example 3 and the reference IR spectra of pure PET and of pure cotton.Fig. 2 shows IR spectra of re-obtained PET (measured twice) obtained according to Example 3 and the refer- ence IR spectra of pure PET and of pure cotton.

Claims

240375W001- 37-Claims1 . A method for separating a polymer blend, wherein the polymer blend comprises(i) a polyester and(ii) one or more component(s) selected from the group consisting of a second polymer, a third polymer, a colorant, and an additive, wherein second polymer and 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 comprising 1 -methylpyrrolidin-2-one;(b) optionally contacting the polymer blend with the solvent comprising 1 -methylpyrrolidin-2-one at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising 1 -methyl pyrrol I- din-2-one, which is enriched in dissolved optional second polymer, in optional colorant and in optional additive or a part thereof; and a residue of the polymer blend, which is depleted of optional second polymer, of optional colorant and of optional additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof; and(c) contacting the polymer blend provided in step (a) or the residue of the polymer blend obtained in step (b) with a solvent comprising 1 -methylpyrrolidin-2-one at a temperature T2 in the range of from > 150 to < 160°C, thereby obtaining a solvent, which comprises 1 -methylpyrrolidin-2-one and which is enriched in dissolved polyester compared to the solvent provided in step (a) and comprises optionally at least a part of the additive, and optionally a residue of the polymer blend, which is depleted of polyester and comprises optionally the third polymer and optionally the additive or a part thereof.

2. The method of claim 1, wherein T1 according to step (b) is in the range of from 120 to < 140°C, more preferably in the range of from 120 to < 135°C; and / or, preferably and, wherein T2 according to step (c) is in the range of from 151 to 159°C.

3. The method of claims 1 or 2, wherein the solvent comprises 1 -methylpyrrolidin-2-one and optionally one or more solvent(s) selected from the group consisting of water and organic solvents having a log Kow in the range of from -1.6 to +1.6, more preferably selected from the group consisting of water, C5 to C12 alkane, aliphatic C1 to C10 alcohol, C3 to C10 ketone, C2 to C10 cyclic ketone, HO-[C1 to C10 alkyl-O-]n-H, with n being an integer in the range of from 2 to 1000, C1 to C10 alkyl-O-C3 to C10 alkyl ether, C3 to C10 cyclic ether, optionally substituted with one or more C1 to C6 alkyl group(s), C6 to C10 aromatic hydrocarbon, optionally substituted with one or more C1 to C6 alkyl group(s), C2 to C10 aliphatic ester, C8 to C11 aromatic ester, C5 to C10 cyclic carboxylic ester (lactone), C3 to C12 amide, preferably R1R2N-C(=O)-R3, wherein R1, R2are independently a C1 to C4 alkyl group and R3is selected from the group consisting of C1 to C9 alkyl group, C1 to C10 ester group and C1 to C6 ether group, unsubstituted C3 to C6 lactame, C3 to C4 or C6 lac- tame substituted with one or more substituent selected from C1 to C6 alkyl group, C1 to C6 ester group and240375W001- 38-C1 to C6 ether group, and C5 imidazolidine, optionally substituted with one or more C1 to C6 alkyl group(s), C5 to C7 imidazolidone, optionally substituted with one or more C1 to C6 alkyl group(s), wherein preferably at least 1 weight-%, more preferably at least 5 weight-%, more preferably at least 10 weight-%, more preferably at least 20 weight-%, more preferably at least 30 weight-%, more preferably at least 40 weight-%, more preferably at least 50 weight-%, more preferably at least 60 weight-%, more preferably at least 70 weight-%, more preferably at least 80 weight-%, more preferably at least 90 weight-%, more preferably at least 95 weight-% of the solvent consists of 1 -methylpyrrolidin-2-one, based on the total weight of the solvent being 100 weight-%.

4. The process of any one of claims 1 to 3, wherein in step (b) and step (c) the same solvent comprising 1- methylpyrrolidin-2-one is used.

5. The method of any one of claims 1 to 4, wherein the polyester is based on 1 ,4-butanediol or 1 ,2-ethandiol, more preferably the polyester according to (I) is selected from the group consisting of a polymer based on 1 ,4-butanediol and terephthalic acid (polybutylene terephthalate, PBT), a polymer based on 1 ,2-ethanediol and terephthalic acid (polyethylene terephthalate, PET), a co-polymer of 1 ,4-butanediol, adipic acid and terephthalic acid (polybutylenadipat-terephthalat, PBAT), a polymer of 1 ,2-ethanediol and 2,5-furandicarboxylic acid (polyethylene furanoate, PEF) and mixtures of two or more of these (co)polymers, more preferably, the polyester comprises at least PET or PBT, more preferably the polyester is PET or PBT or a mixture of PET and PBT; and / or, preferably and, 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 a copolymer of PU and PEG and / or pTHF, more preferably spandex (copolymer of PU and PEG or of PU and pTHF); and / or, preferably and, wherein the third polymer is selected from the group consisting of polyolefins, preferably polyethylene (PE) and polypropylene (PP), polyamide (PA), natural polymer, preferably wool, cotton or viscose, mixtures of two or more of these polymers and copolymers of two or more of these polymers, wherein the third polymer is preferably selected from PA, wool, cotton, viscose and mixtures of two or more of these polymers; and / or, preferably and, wherein the colorant is selected from the group consisting of dye and optical brightener and mixtures of dye and optical brightener, and / or, preferably and, wherein the additive is selected from the group consisting of softener, water repellent, flame retardant, UV filter, plasticizer, filler and mixtures of two or more thereof.

6. The method of any one of claims 1 to 4, wherein step (b) and / or step (c) are done in a gaseous atmosphere comprising at least one inert gas, preferably in a gaseous atmosphere comprising nitrogen.

7. The method of any one of claims 1 to 6, wherein step (b) comprises:(b.1) contacting the polymer blend with the solvent comprising 1 -methylpyrrolidin-2-one at a temperature T1 of < 140 °C, preferably of < 135°C, thereby obtaining a solvent comprising 1 -methylpyrrolidin-2-one,240375W001- 39- which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof; and a residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof;(b.2) separating the solvent, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof, and the residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof obtained in step (b.1 ), preferably by a physical separation method, thereby obtaining a separated solvent, which is enriched in dissolved optional second polymer, in optional colorant and optionally the additive or a part thereof compared to the solvent provided in step (a) and the residue of the polymer blend, which is depleted of said optional second polymer, of said optional colorant and optionally of additive or part thereof; and comprises the polyester, optionally the third polymer; and the optional additive or a part thereof.

8. The method of any one of claims 1 to 7, preferably of claim 7, wherein step (b) further comprises:(b.3) washing the separated residue of the polymer blend obtained in step (b.2) at least once with a washing solvent comprising 1 -methylpyrrolidin-2-one and optionally one or more solvent(s) selected from the group indicated above, thereby obtaining a washed residue;(b.4) optionally drying the washed residue obtained in step (b.3).

9. The method of any one of claims 1 to 8, wherein the polymer blend comprises at least a third polymer, the method comprising d) separation of the solvent system, which is enriched in dissolved polyester obtained in step (c) from the residue obtained in step (c), thereby obtaining a solvent enriched in dissolved polyester, which is free of third polymer, and a residue comprising at least the third polymer, wherein the separation is done by heated solid-liquid separation, preferably at a temperature in the range of T ± 20°C, more preferably at a temperature in the range of T ± 10°C.

10. The method of any one of claims 1 to 9 further comprising(e) optionally after heated filtration according to d), cooling the solvent obtained in step (c) or in step (d), which is enriched in dissolved polyester compared to the solvent provided in step (a), to a temperature below T2 preferably below 150°C, more preferably below 140°C, more preferably below 120°C; thereby obtaining a precipitated polyester and a solvent, which is depleted in dissolved polyester; wherein cooling in step (e) is preferably done without addition of antisolvents; and / or, preferably and, comprising240375W001- 40-(f) separating the precipitated polyester obtained in step (e) from the solvent, which is depleted in dissolved polyester, thereby obtaining a precipitated polyester and the solvent, which is depleted in dissolved polyester; and / or, preferably and, comprising(g) optionally washing the precipitated polyester obtained in step (f);(h) drying the precipitated polyester obtained in step (f) or the washed precipitated polyester obtained in step (g).

11. The method for separating a polymer blend of any one of claims 1 to 10 comprising recycling solvent re-ob- tained from one or more step(s), preferably the separated solvent obtained in step (b.2), the washing solvent from step (b.3), the separated solvent of step (d), the separated solvent of step (f), and / or the washing solvent of step (g) at least partially to step (b) and / or step (c), optionally after one or more work-up step(s).

12. A polyester obtained or obtainable from the method according to any one of claims 1 to 11, preferably from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to any one of claims 1 to 11 .

13. Use of the polyester of claim 12 for preparation of textile applications, fiber applications, packaging applications, plastic applications, automotive applications, electronic applications, preferably for the production of food packaging, beverage packaging, clothing, foot wear, wire, cable, wherein preferably in case that the polyester is selected from PBAT, PEF and PET, preferably PET, the polyester is used for textile applications, fiber applications, packaging applications, plastic applications, more preferably for the production of food packaging, beverage packaging, clothing and foot wear; wherein in case that the polyester is PBT, the polyester is used in textile applications, automotive applications, electronic applications, more preferably for the production of a wire and / or a cable.

14. A method for preparing a product comprising(I) providing a polyester of claim 12;(II) preparing a textile, a fiber, a packaging, a plastic, an automotive part, an electronic part from the polyester provided in step (I).

15. Method, preferably according to any one of claims 1 to 11, comprising the step of converting the polyester obtained or obtainable from the method according to any one of claims 1 to 11 , preferably from step (b), step (b.2), step (b.3), step (b.4), step (c), step (d), step (e), step (f), step (g) and / or from step (h) according to any one of claims 1 to 11, or the second polymer obtained or obtainable from the method according to any one of claims 1 to 11, or the third polymer obtained or obtainable from the method according to any one of claims 1240375W001- 41- to 11, or a chemical material obtainable by or obtained by the method according to any one of any one of claims 1 to 11, to obtain a product PRF1.

16. A product PRF1, obtained or obtainable from the method of claim 15.

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