TW202511372A - Process for recycling of a colored polymeric material including discoloration and chemical processing - Google Patents

Abstract

A first aspect of the invention relates to a process for recycling of a colored polymeric material, wherein the colored polymeric material comprises (i) a polyalkylene terephthalate based polymer, (ii) a colorant and optionally (iii) a second polymer different from the polyalkylene terephthalate based polymer of (i) and optionally (iv) a third polymer different from the polyalkylene terephthalate based polymer of (i) and different from the second polymer of (iii), the process comprising (a) providing a colored polymeric material and a solvent system comprising gamma valerolactone (GVL); (b) contacting the colored polymeric material provided in (a) with the solvent system comprising GVL provided in (a) under conditions allowing for colorant removal but not allowing for dissolution of the polyalkylene terephthalate based polymer, thereby obtaining a solvent system, which is enriched in colorant compared to the solvent system provided, and a polymeric material, which is depleted in colorant compared to the colored polymeric material provided in (a); (c) depolymerisation or transesterification of the polymeric material, which is depleted in colorant obtained in (b); thereby obtaining monomers and/or oligomers or transesterification products. In a second aspect, the invention relates to a monomer, oligomer or transesterification product of a polyalkylene terephthalate based polymer obtained or obtainable by the process of the first aspect. A third aspect relates to a process comprising converting, preferably polymerizing, the monomers, oligomers or transesterification products of a polyalkylene terephthalate based polymer obtained from the process of the first aspect to obtain one or more polymer or polymer product. A fourth aspect relates to a process comprising converting the separated second polymer (iii) and/or the separated third polymer (iv) obtainable by or obtained from the process of the first aspect to obtain one or more monomer, polymer or polymer product.

Description

Method for recycling colored polymeric materials comprising decolorization and chemical treatment

A first aspect of the present invention relates to a method for recycling a colored polymeric material, wherein the colored polymeric material comprises (i) a polyalkylene terephthalate-based polymer; (ii) a colorant; and optionally (iii) a second polymer different from the polyalkylene terephthalate-based polymer of (i); and optionally (iv) a third polymer different from the polyalkylene terephthalate-based polymer of (i) and different from the second polymer of (iii), the method comprising (a) providing a colored polymeric material and a colorant comprising gamma valerolactone ( (b) contacting the colored polymeric material provided in (a) with the solvent system comprising GVL provided in (a) under conditions that allow the removal of the colorant but do not allow the dissolution of the polyalkylene terephthalate-based polymer, thereby obtaining a solvent system rich in colorant compared to the provided solvent system, and a polymeric material with reduced colorant compared to the colored polymeric material provided in (a); (c) depolymerizing or transesterifying the polymeric material with reduced colorant obtained in (b); thereby obtaining monomers and/or oligomers or transesterification products. In a second aspect, the present invention relates to a monomer, oligomer or transesterification product of a polyalkylene terephthalate-based polymer, which is obtained or obtainable by the method of the first aspect. A third aspect relates to a method, which comprises converting, preferably polymerizing, a monomer, oligomer or transesterification product of a polyalkylene terephthalate-based polymer obtained from the method of the first aspect to obtain one or more polymers or polymer products. A fourth aspect relates to a method, which comprises converting an isolated second polymer (iii) obtainable by or obtained from the method of the first aspect and/or an isolated third polymer (iv) to obtain one or more monomers, polymers or polymer products.

Over the past decades, the demand for polymeric materials has increased dramatically. However, the poor biodegradability leads to the generation of large amounts of plastic waste, which in Europe is usually incinerated, with the loss of valuable material and the generation of large amounts of CO ₂ emissions. Landfills are even worse due to the poor biodegradability. Polymeric materials based on polyester have been widely used in the packaging sector, for example for beverage packaging or food packaging. Today, the vast majority of food and beverages are packaged in plastic bottles and containers made of polyester materials, such as polyethylene terephthalate (PET). PET is also a major component of clothing today. Since these materials generally have poor biodegradability and are also still valuable products, there is a need to recover and recycle these plastics.

Despite the fact that recycling methods have been adopted to convert waste materials into new production materials, there are still many problems associated with the recycling and recovery of polymeric materials. Waste packaging often comprises a mixture of different polymeric materials which also contain, for example, colorants. The same applies to textiles, which also contain a large amount of colored polymeric materials. Therefore, in order to recycle polymeric materials, the polymeric materials are usually separated based on their color and/or their composition. However, this sorting process is labor-intensive and/or requires the use of sorting machines.

With regard to the removal of colorants, EP 2 784 110 A1 describes the removal of organic colorants from polyethylene terephthalate (PET) flakes from shredded PET bottles by extracting the PET flakes with ethylene glycol at ambient pressure and at the boiling temperature of ethylene glycol. US 10,876,240 B2 is about the decolorization of dyed polyester with the gaseous propylene glycol methyl ether. DE 2223466 A1 discloses a method for separating substances from substrates with a solvent at high temperature, wherein the substrate is heated by means of condensed vapors of a liquid that is miscible with the solvent but does not dissolve the substrate, and the heated substrate is subsequently treated with a solvent, thereby separating the substance from the substrate.

Although several methods are known for removing coloring agents from polyesters, these methods still have disadvantages: the depolymerization or transesterification of the colored polymeric material must be delivered by fully purified monomers and/or other esters by filtration, crystallization or distillation. This makes the process extremely expensive. If decolorization cannot be achieved, the product is of low quality and can no longer be used in high-value applications.

In addition, the presence of additional components in the blend (such as other polymers) may cause interference or may not be removed in the same way as the coloring agent. Other disadvantages are the necessity to use toxic solvents and/or the need to use large amounts of solvents.

The technical problem underlying the present invention is therefore that of providing an economical process for the recycling of polyester which overcomes these disadvantages and which in particular makes it possible, on the one hand, to precisely remove the coloring agents and, if present, other polymers while using relatively small amounts of solvent and, on the other hand, to recover undegraded polyester which can subsequently be easily converted into suitable monomer building blocks.

The first aspect of the present invention relates to a method for recycling a colored polymeric material, wherein the colored polymeric material comprises (i) a polyalkylene terephthalate-based polymer; (ii) a colorant; and optionally (iii) a second polymer that is different from the polyalkylene terephthalate-based polymer of (i); and optionally (iv) a third polymer that is different from the polyalkylene terephthalate-based polymer of (i) and different from the second polymer of (iii), the method comprising: (a) providing a colored polymeric material and a solvent system; (b) The colored polymeric material provided in (a) is contacted with the solvent system provided in (a) under conditions that allow the removal of the colorant but do not allow the polyalkylene terephthalate-based polymer to dissolve, thereby obtaining a solvent system rich in colorant compared to the solvent system provided, and a polymeric material with reduced colorant compared to the colored polymeric material provided in (a); (c) depolymerizing or transesterifying the polymeric material with reduced colorant obtained in (b); thereby obtaining monomers and/or oligomers or transesterification products.

The process of the invention represents an extremely simple and effective method for decolorizing polyalkylene terephthalate-based polymers without affecting the polymeric structure and in particular without degrading the polyalkylene terephthalate-based polymers. Thereafter, the material can be easily chemically treated (via depolymerization or transesterification) without the need for extensive purification of the resulting product due to color.

The "contacting under conditions that allow the removal of the coloring agent but do not allow the polyester to dissolve" in step (b) includes any kind of contact between the colored polymeric material and the solvent system, as long as the coloring agent and, if present, the third polymer (iv) are reduced while the polyalkylene terephthalate-based polymer remains undegraded. As described in more detail below, in particular in some embodiments, this includes contacting the colored polymeric material with a gaseous solvent system and/or a recondensed solvent system, while in some alternative embodiments, the colored polymeric material is at least partially immersed in a (liquid) solvent system.

"Colorant-reduced" means that at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight of the colorant is removed from the polymeric material, and (if present) the same perceived amount of the third polymer (iv) contained in the colored polymeric material provided in (a), more preferably the above-mentioned amount of the colorant contained in the polyalkylene terephthalate-based polymer, and (if present) the third polymer (iv) contained in the colored polymeric material provided in (a). "Colorant-rich" means that at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight of the colorant and (if present) the same perceived amount of the third polymer (iv) contained in the material provided in (a) are dissolved in the solvent system.

( b ) Removal of colorant by gas stream In some embodiments of the method, (b) comprises: (b.1) providing the colored polymeric material in a first container and providing the solvent system in a second container; wherein the first container and the second container are spatially separated from each other but allow gas and fluid communication between each other; (b.2) forming a gas stream containing at least a portion of the solvent system, and removing the gas stream from the second container; (b.3) separating the solvent system in liquid form from the gas stream at a position outside the second container (also outside the first container) to obtain a solvent system in liquid form; (b.4) contacting the colored polymeric material in the first container with the solvent system in liquid form, the solvent system having been separated from the gas stream in (b.3), Thereby, a solvent system is obtained which is rich in colorant and, if appropriate, in a third polymer (iv) compared to the solvent system provided in (a), and a polymeric material which is reduced in colorant and, if appropriate, in a third polymer (iv) compared to the colored polymeric material provided in (a) and comprises the polyalkylene terephthalate-based polymer (i) and, if appropriate, the second polymer (iii).

The expression "allowing gaseous and fluid communication therebetween" means that the colored polymeric material in the first container and the solvent system in the second container are not in direct contact with each other, and that gases, vapor phases and liquids can move freely between and around them.

The expression "gas stream comprising at least part of the solvent system" is to be understood as meaning firstly that a part of the solvent system remains in the second container and secondly that the gas stream comprises at least a part of the solvent system, wherein the solvent system is present in the gas stream in liquid or gaseous state or partly in liquid and partly in gaseous state.

The location outside the second container (and also outside the first container) is any location outside of both containers, wherein the only requirement is that the solvent system can be separated from the gas stream in liquid form and transferred back to the polymerized material in the first container by any suitable means.

In these embodiments, "contacting" particularly includes contacting the colored polymeric material with a gaseous solvent system and/or a recondensed solvent system and/or a separated solvent system, as described in more detail below.

In some embodiments of the method, (b.2) comprises: (b.2.1) heating the solvent system to a temperature at least equal to or greater than the boiling temperature of the solvent system; (b.2.2) obtaining a gas stream comprising at least a portion of the solvent system, and removing the gas stream from the second container.

In some embodiments, the solvent system at least partially transfers from the liquid state to the gaseous state due to heating. If two or more solvents are present in the solvent system, the "boiling point" of the solvent system is understood to be the boiling point range of the solvent system in the case of a non-azeotropic mixture, or in the case of an azeotropic mixture, the boiling point of the azeotropic mixture. The boiling point of a solvent is generally understood to be the boiling point of the solvent at the respective pressure, and the boiling point of a solvent system is likewise understood to be the boiling point of the solvent system at the respective pressure. In some embodiments of the method, an inert gas is additionally applied, which forms part of the gas stream comprising at least part of the solvent system.

In some embodiments of the method, (b.2) comprises: (b.2.1') heating the solvent system to a temperature T which is at most 3 K below the boiling temperature of the solvent system; so as to obtain a solvent system with an elevated temperature; (b.2.2') contacting the solvent system with an elevated temperature with an inert gas, preferably passing the inert gas through the solvent system with an elevated temperature, so as to form a gas stream comprising at least part of the solvent system, and removing the gas stream from the second container.

The solvent system in (b.2.1') is heated to a temperature in the range of 30°C, preferably 160°C to a temperature at most 3 K below the boiling temperature of the solvent system, wherein when step (b.ii.1') is carried out under a pressure in the range of 990 to 1030 hPa, 30°C or 160°C is preferably applied. In some embodiments of the method, at least one of (b.2), (b.3) and (b.4), preferably (b.1), (b.2), (b.3) and (b.4) is carried out under a pressure in the range of 800 to 200,000 hPa; the same applies to all sub-steps described above and below. In some alternative embodiments, at least one of (b.2), (b.3) and (b.4), preferably (b.1), (b.2), (b.3) and (b.4) is performed under a pressure in the range of 0.1 to 990 hPa, preferably in the range of 1 to 990 hPa; the same applies to all sub-steps described above and below.

In some embodiments of the method, (b.3) includes: (b.3.1) transferring the gas flow from the second container to a position outside the second container (also outside the first container); (b.3.2) separating the portion of the solvent system contained in the gas flow in liquid form from the gas flow at a position outside the second container (also outside the first container) to obtain a solvent system in liquid form.

The separation of the solvent system in (b.3.2) is carried out by any means suitable for separating the solvent system from a gaseous flow so that the solvent system is obtained in liquid form. For example, the separation is carried out by cooling the gaseous flow containing at least part of the solvent system, for example by contact with the surface of a component whose temperature is lower than the temperature of the gaseous flow. In some embodiments, when the method is carried out in an extraction device, such as a Soxhlet extractor, the component whose temperature is lower than the temperature of the solvent system is a condenser, preferably a condenser through which a cooling medium is guided. Separation means that condensation is carried out while at least part of the solvent system is at least partly in the gaseous flow. In the case where at least part of the solvent system is still at least partly in liquid form in the gas stream, separation means stripping these liquid parts from the gas stream.

In some embodiments of the method, (b.4) comprises: (b.4.1) transferring the liquid form solvent system obtained in (b.3.2) to the colored polymeric material in the first container; (b.4.2) contacting the colored polymeric material in the first container with the liquid form solvent system, thereby obtaining a solvent system rich in colorant and, if appropriate, third polymer compared to the solvent system provided in (a), and a polymeric material, which is reduced in colorant and, if appropriate, third polymer compared to the colored polymeric material provided in (a) and comprises the polyalkylene terephthalate-based polymer and, if appropriate, the second polymer.

In some embodiments of the method, (b.4) comprises: (b.4.3) transferring the solvent system obtained in (b.4.2) to a second container, wherein the second container contains the solvent system provided in (a).

In some embodiments of the method, a first container containing a polymeric material and a second container containing a solvent system are spatially separated from each other, wherein the first container containing the polymeric material is arranged above the second container containing the solvent system. The expression "arranged above the second container containing the solvent" means that the polymeric material is arranged at a position vertically higher than the position of the upper edge of the solvent system in the second container. Preferably, there is no direct material contact between the polymeric material and the solvent system, that is, the polymeric material neither contacts the surface of the solvent system nor any percentage of the polymeric material is immersed in the solvent system in the container. The device that can be used to perform the method is not limited. For example, in some embodiments, a device equivalent to a Soxhlet extractor is used, wherein the second container containing the solvent system is equivalent to a distillation kettle, and the first container containing the polymeric material is equivalent to an extraction thimble. In some embodiments, the first container is a device having one or more openings, such as a sieve. The sieve can have any conceivable shape, such as a flat sieve, a curved sieve, etc., as long as the sieve can contain the polymeric material (in a solid state) but allow liquids and gases to pass through its openings.

In some embodiments of the method, (b.4.2) includes contacting the colored polymeric material with the liquid solvent system of (b.4.1), wherein the liquid solvent system is dripped onto the colored polymeric material.

In some embodiments of the method, (b.4.3) comprises transferring a solvent system that is enriched in a colorant and, optionally, a third polymer compared to the solvent system provided in (a) from a first container to a second container, wherein the solvent system drips (returns) from the first container to the second container in liquid form.

In some embodiments, the method comprises: (b.1) providing a colored polymeric material in a first container and providing a solvent system in a second container; wherein the first container and the second container are spatially separated from each other, wherein the first container containing the colored polymeric material is disposed above the second container containing the solvent system and allows gas and fluid communication between the first container and the second container; (b.2) forming a gas flow containing at least a portion of the solvent system and removing the gas flow from the second container; (b.3.1) transferring the gas flow from the second container to a location outside the second container (also outside the first container); (b.3.2) Separating a portion of the solvent system contained in the gas stream in liquid form from the gas stream at a position outside the second container (also outside the first container), preferably at a position above the first container, wherein the separation is preferably performed by cooling the gas stream containing at least a portion of the solvent system, and more preferably by bringing the gas stream at a position above the first container into contact with the surface of a component having a temperature lower than that of the gas stream; thereby obtaining a solvent system in liquid form; (b.4.1) Transferring the solvent system in liquid form obtained in (b.3.2) to the colored polymer material in the first container, wherein the solvent system in liquid form drips from a position above the first container onto the colored polymer material in the first container; (b.4.2) The colored polymeric material in the first container is brought into contact with the solvent system in liquid form, thereby obtaining a solvent system that is rich in colorant and, if appropriate, a third polymer compared to the solvent system provided in (a), and a polymeric material that is reduced in colorant and, if appropriate, a third polymer compared to the colored polymeric material provided in (a) and comprises a polymer based on polyalkylene terephthalate and, if appropriate, a second polymer; and preferably (b.4.3) The solvent system obtained in (b.4.2) is transferred to a second container, the second container containing the solvent system provided in (a), preferably, wherein a solvent system enriched in a coloring agent and optionally a third polymer compared to the solvent system provided in (a) drips (returns) from the first container to the second container in liquid form.

For these embodiments, all preferred options described above with respect to (b.2.1), (b.2.1'), (b.2.2) and/or (b.2.2') also apply.

In some embodiments of the method, the inert gas is selected from the group consisting of argon, helium, neon, nitrogen and a mixture of two or more of these inert gases, preferably at least comprises nitrogen, and more preferably, the inert gas is nitrogen.

In some embodiments of the method, the inert gas is directed through the solvent system at a flow rate in the range of 1 to 150 liters per hour, or the inert gas is passed along the surface of the solvent system at a flow rate in the range of 1 to 150 liters per hour.

In some embodiments, the method further comprises: (b.5) removing the colorant-rich and optionally third polymer-rich solvent system obtained in (b.4) or (b.4.2) from the polymeric material (i.e. also from the first container), and preferably recirculating it to the second container containing the solvent system by dripping it into the second container containing the solvent system (causing the solvent system obtained in (b.4) or (b.4.2) to drip into the second container containing the solvent system).

In some embodiments of the method, (b.2), (b.3) and (b.4), preferably (b.2), (b.3), (b.4) and (b.5) are performed in a continuous mode.

In some embodiments, the method further comprises: (b.6) at least partially removing the polymeric material obtained in (b.4) or (b.4.2), thereby obtaining a polymeric material having a reduced colorant and optionally a reduced third polymer (iv) compared to the colored polymeric material provided in (a) and comprising the polyalkylene terephthalate-based polymer and optionally the second polymer.

In some embodiments, the method further comprises: (b.7) replacing at least part of the polymeric material removed in (b.6) with fresh colored polymeric material without replacing the solvent system provided in (a), wherein the fresh colored polymeric material comprises a polyalkylene terephthalate-based polymer, a coloring agent, a second polymer, if present, and a third polymer, if present, and repeating steps (b.2), (b.3) and (b.4), and repeating (b.5) if necessary; wherein steps (b.6) and (b.7) are preferably repeated at least once, preferably repeated once to at least 10 times (batch mode); or wherein steps (b.6) and (b.7) are performed continuously (sweep mode).

In some embodiments of the method, additional fresh solvent system is added in a range of 1 to 50 wt %, based on the total weight of the solvent system provided in (a) as 100 wt %, wherein the addition is performed discontinuously (batch mode) or continuously (sweep mode).

Removal of the colorant by treatment in solution in ( b ) In some alternative embodiments of the method, (b.1) comprises: (b.1') contacting the colored polymeric material of (a) with a solvent system at a temperature T of <170°C, thereby obtaining a solvent system rich in colorant and, optionally, rich in a third polymer (iv) compared to the solvent system provided in (a), and a polymeric material with reduced colorant and, optionally, reduced third polymer (iv) compared to the colored polymeric material provided in (a); (b.2') optionally separating the polymeric material from the solvent system, wherein the colorant and, optionally, the third polymer (iv) are reduced and the polymer comprises the polyalkylene terephthalate-based polymer.

The separation in (b.2') is carried out by methods and means known to the person skilled in the art, in particular by solid-liquid separation methods, such as filtration, for example heated pressure filtration, sedimentation or centrifugation (see Handbuch der mechanischen Fest-Flüssig-Trennung Taschenbuch - April 29, 2004 von Klaus Luckert (Herausgeber)). The coloring agent at least partially remains in the separated solvent system obtained in (b.2').

In these alternative embodiments of the method, it is preferred that the contacting in (b.1') is carried out at a temperature T in the range of 10 to <170°C, preferably in the range of 100 to <170°C, more preferably in the range of 110 to <170°C, more preferably in the range of 110 to 165°C, and more preferably in the range of 120 to 150°C.

The "contact" in step (b.1') preferably means that the colored polymeric material is at least partially immersed in the solvent system. Preferably, the colored polymeric material is at least partially immersed in the (first or second) solvent system, wherein 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 colored polymeric material is immersed in the solvent system or in contact with the solvent system, based on the total surface as 100%.

In these alternative embodiments of the method, it is preferred that (b.1') is carried out at a pressure in the range of 800 to 200,000 hPa.

In some embodiments of the method, at least (b) is performed in a countercurrent mode. For example, if the contacting of step (b) is performed in a container, the solvent system enters the container from one direction (side or top/bottom) and the colored polymeric material enters the container from another direction, preferably an opposite direction. In a preferred cluster using a vertically configured container, the solvent system enters the container from the bottom and the colored polymeric material enters the container from the top. In some embodiments of the method, at least (b) is performed under mechanical intermixing, wherein the mechanical intermixing preferably comprises one or more methods selected from stirring, blending and ultrasound.

Additional Step Washing In some embodiments of the method, (b) comprises: (by) washing the polymeric material separated in (b.6) or (b.2') with a washing solvent, as appropriate, thereby obtaining a washed polymeric material having reduced coloring agents compared to the polymeric material provided in (a).

Drying In some embodiments of the method, (b) comprises: (bz) drying the polymeric material separated in (b.6) or (b.2') and/or the washed polymeric material obtained in (by), respectively.

The washing in the optional step (b.y) is preferably carried out with a solvent system having the characteristics (s.1) or (s.1a), preferably (s.1) or (s.1a) and (s.2), more preferably (s.1) or (s.1a), (s.2) and (s.3), preferably with a solvent system comprising one or more of any group of solvents listed herein. Preferably, the washing in the optional step (b.y) is carried out with the same solvent system used for color reduction. In some embodiments, the washing is performed with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, or a mixture of two or more of these solvents. In some embodiments, the washing in the optional step (b.y) is performed with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, or a mixture of two or more of these solvents. The drying in step (b.z) is preferably carried out under one or more conditions selected from the group consisting of: a pressure in the range of 1 to 1013 mbar; a temperature in the range of 50 to 210°C, preferably in the range of 60 to 180°C, more preferably in the range of 80 to 160°C; a drying time in the range of 30 minutes to 24 hours; 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 carried out by one or more methods selected from the group consisting of: contact drying, convection drying and radiation drying.

Solvent system In some embodiments of the method, the solvent system comprises one or more solvents, wherein the solvent system (s.1) has a Hansen solubility parameter relative to - energy from dispersion forces between molecules (δD _ss ), - energy from dipole intermolecular forces between molecules (δP _ss ) and - energy from hydrogen bonds between molecules (δH _ss ), which satisfies Equation 1 (11) ² ≥ 4(δD _ss -17.5) ² + (δP _ss -7.5) ² + (δH _ss -7.5) ² [Equation 1].

Preferably, the solvent system (s.1a) has Hansen solubility parameters relative to - energy from dispersion forces between molecules (δD _ss ), - energy from dipole intermolecular forces between molecules (δP _ss ) and - energy from hydrogen bonds between molecules (δH _ss ), which satisfy Equation 2 (8.8) ² ≥ 4(δD _ss -20) ² + (δP _ss -11.8) ² + (δH _ss -4.5) ² [Equation 2].

With respect to the solvent system, any solvent system wherein 4(δD _ss -17.5) ² + (δP _ss -7.5) ² + (δH _ss -7.5) ² is greater than (11) ² (i.e., 121), preferably any solvent system wherein 4(δD _ss -20) ² + (δP _ss -11.8) ² + (δH _ss -4.5) ² is greater than (8.8) ² (i.e., 77.44) is not suitable for dissolving the colorant while rendering the polyalkylene terephthalate-based polymer almost completely insoluble and non-degradable, and wherein 4(δD _ss -17.5) ² + (δP _ss -7.5) ² + (δH _ss -7.5) ² is less than or equal to (11) ² Any solvent system wherein 4(δD _ss -20) ² + (δP _ss -11.8) ² + (δH _ss -4.5) ² is less than or equal to (8.8) ² (i.e. 77.44) is suitable for dissolving the colorant while rendering the polyalkylene terephthalate-based polymer almost completely insoluble and non-degradable within a specified temperature range. If two or more solvents are part of a solvent system, i.e. n solvents, where n is an integer, where n ≥ 2 and i = 1…n, then the Hansen solubility parameters of the resulting mixture relative to each of δD _ss , δH _ss and δP _ss are calculated, given the percentage part of each solvent in the solvent system, as the weighted arithmetic mean of δD _si , δH _si and δP _si of each of the n solvents S(i). Hansen parameters will be available in BIOVIA COSMOquick 2022.

Considering the three-dimensional form given by, for example, equation 2 in three-dimensional Hansen space, a sphere is formed with center at δD _c = 20, δP _c = 11.8 and δH _c = 4.5 and radius r of 8.8. According to Charles Hansen, to achieve the spherical form, the dispersion parameter values need to be doubled. Since negative values of δH are not possible, the Hansen sphere can also be considered as a dome, i.e. a hemisphere. The same principle applies to the three-dimensional form given by equation 1 in three-dimensional Hansen space.

In some embodiments of the method, (s.2) each solvent of the solvent system has a boiling point at 1013 hPa of at least 150°C, preferably at least 160°C.

In some embodiments of the method, (s.3) does not include a solvent having a functional group selected from the group consisting of a hydroxyl group (OH), an amine group (NH ₂ ), a carboxyl group (COOH), and a thiol group (SH).

In some embodiments of the method, (s.3a) excludes a solvent having a functional group selected from the group consisting of a hydroxyl group (OH), an amine group (NH ₂ ), a diamine (—NH—), a carboxyl group (COOH), and a thiol group (SH).

In some embodiments of the method, based on the total weight of the solvent system as 100 weight %, at least 90 weight %, preferably at least 95 weight %, more preferably at least 98 weight %, and more preferably in the range of 99 to 100 weight % of the solvent system consists of two or more solvents.

In some embodiments of the method, based on the total weight of the solvent system as 100 weight %, at least 90 weight %, preferably at least 95 weight %, more preferably at least 98 weight %, and more preferably in the range of 99 to 100 weight % of the solvent system is composed of one solvent that satisfies Equation 1 and/or 2.

In some embodiments of the method, one or more solvents of the solvent system are selected from the group consisting of: N,N-dimethylbenzamide, N,N-dimethylphenylacetamide, 1,4-benzoquinone, acetophenone, dimethyl terephthalate, 1,3,5-trimethoxybenzene, 2-phenylacetophenone, N-methylcaprolactam, methyl benzoate, methyl-4-methoxybenzoate, butyl carbonate, propylene-glycol-dibenzoate, N-ethyl pyrrolidone, benzophenone, benzhydryl malonate, N-ethyl-caprolactam, 2-(5-hydroxytetrahydrofuran-3-yl)acetate methyl ester (FAME), propiophenone, N-methoxypropyl-pyrrolidone, 1,4-cyclohexanedione, cyclohexane-carbonate, N-methoxyethyl-pyrrolidone, N,N-diethylphenylacetamide, phenyl acetate, 1-(2-hydroxyethyl)pyrrolidone-2-one acetate (HEPAc), N,N-diethylbenzamide, isopropyl-benzoate, cyclohexylphenyl ketone, ethyl phenylacetate, phenylacetate, N-methyl-phenoxy, benzyl-propionate, benzyl acetate, neopentyl-diol-dibenzoate, tetrahydrofuran acetate, N-methyl-imidazole, benzyl butyrate, 2-pyrrolidone, 2-phenoxyethanol propionate, 2-phenoxyethyl isobutyrate, N,N-dipropylbenzamide, N,N-dimethylacetamide, N,N-diethylacetamide, dihydro-levoglucosone (Cyrene), propyl carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-hydroxypyrrolidine-3-carboxylate (MMOC), γ-valerolactone (GVL), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-hydroxypentanoate (Rhodiasolv Polarclean), caprolactamide, ethyl phenylacetate, methyl phenylacetate, benzyl benzoate, N,N-dimethyllactamide (Agnique AMD 3L), and dimethylsulfoxide (DMSO).

In some embodiments of the method, one or more solvents of the solvent system are selected from the group consisting of dihydrolevorotatory glucosone (Cyrene), propyl carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-hydroxypyrrolidine-3-carboxylate (MMOC), γ-valerolactone (GVL), δ-valerolactone, γ-butyrolactone, 5-(dimethylamino)-2-methyl-5-hydroxypentanoic acid methyl ester (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenyl acetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate and dimethyl sulfoxide (DMSO).

In some embodiments of the method, one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopentylpyrrolidine-3-carboxylate (MMOC), delta-valerolactone, gamma-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopentylvalerate (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and GVL.

In some embodiments of the method, one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopentylpyrrolidine-3-carboxylate (MMOC), delta-valerolactone, gamma-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopentylvalerate (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, and propyl benzoate.

In some embodiments of the method, one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidine-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polarclean), phenethyl acetate, and GVL.

In some embodiments of the method, one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidine-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polarclean), and phenethyl acetate.

In some embodiments of the method, one or more solvents are selected from the group consisting of: gamma valerolactone (GVL), N-butylpyrrolidone (NBP), propyl carbonate, acetophenone, dimethyl sulfoxide (DMSO), dihydro-levoglucose ketone (Cyrene), cyclohexanone, and mixtures of two or more thereof. In some embodiments of the method, one or more solvents are selected from the group consisting of: gamma valerolactone (GVL), N-butylpyrrolidone (NBP), propyl carbonate, acetophenone, dimethyl sulfoxide (DMSO), dihydro-levoglucose ketone (Cyrene), and mixtures of two or more thereof. In some embodiments of the method, the one or more solvents are selected from the group consisting of gamma valerolactone (GVL), N-butylpyrrolidone (NBP), propyl carbonate, acetophenone, dimethyl sulfoxide (DMSO), and mixtures of two or more thereof. In some embodiments of the method, the one or more solvents are selected from the group consisting of gamma valerolactone (GVL), N-butylpyrrolidone (NBP), propyl carbonate, acetophenone, and mixtures of two or more thereof. In some embodiments of the method, the one or more solvents are selected from the group consisting of gamma valerolactone (GVL), N-butylpyrrolidone (NBP), acetophenone, and mixtures of two or more thereof. In some embodiments of the method, the one or more solvents are selected from the group consisting of gamma valerolactone (GVL), N-butylpyrrolidone (NBP), and a mixture of GVL and NBP.

In some embodiments of the method, one or more solvents are selected from the group consisting of: N-butylpyrrolidone (NBP), propyl carbonate, acetophenone, dimethyl sulfoxide (DMSO), dihydro-levoglucose ketone (Cyrene), cyclohexanone, and mixtures of two or more thereof. In some embodiments of the method, one or more solvents are selected from the group consisting of: N-butylpyrrolidone (NBP), propyl carbonate, acetophenone, dimethyl sulfoxide (DMSO), dihydro-levoglucose ketone (Cyrene), and mixtures of two or more thereof. In some embodiments of the method, one or more solvents are selected from the group consisting of: N-butylpyrrolidone (NBP), propyl carbonate, acetophenone, dimethyl sulfoxide (DMSO), and mixtures of two or more thereof. In some embodiments of the method, the one or more solvents are selected from the group consisting of: N-butylpyrrolidone (NBP), propylene carbonate, acetophenone, and mixtures of two or more thereof. In some embodiments of the method, the one or more solvents are selected from the group consisting of: N-butylpyrrolidone (NBP), acetophenone, and mixtures of N-butylpyrrolidone (NBP) and acetophenone.

In some embodiments of the method, the one or more solvents contain at least N-butylpyrrolidone, and based on the total weight of the one or more solvents as 100 weight%, preferably at least 90 weight% of the one or more solvents, more preferably at least 95 weight%, more preferably at least 98 weight%, more preferably at least 99 weight%, more preferably at least 99.5 weight%, and more preferably at least 99.9 weight% of the one or more solvents are N-butylpyrrolidone. More preferably, the one solvent is N-butylpyrrolidone. In some embodiments, the contacting in (b.1') is carried out at a temperature T, which may be in the range of 10 to <170°C, wherein T may preferably be in the range of 140 to 160°C, more preferably in the range of 150 to 160°C, or the contacting in (b.1') is carried out at a temperature T, which may be in the range of 101 to 81 K below the boiling point of N-butylpyrrolidone, preferably in the range of 91 to 81 K below the boiling point of N-butylpyrrolidone. The contacting in (b.1') is preferably carried out under a pressure in the range of 800 to 1200 hPa. Preferably, the process is run under autogenous pressure, wherein the autogenous pressure can be higher than the ambient pressure in the surrounding area caused by the vapor pressure of N-butylpyrrolidone at the temperature T at which the process is run. The person skilled in the art can determine and/or adjust the autogenous pressure based on the vapor pressure curve of N-butylpyrrolidone at a certain temperature T. The vapor pressure curve of N-butylpyrrolidone is known to the person skilled in the art. The autogenous pressure can be reduced by blowing (for example by means of a blow-off valve), preferably to a pressure between the ambient pressure and below 2000 hPa, preferably to a pressure between 1200 hPa and 1800 hPa. Autogenous pressure is the pressure caused by the production system itself in a closed system, for example in the range of 800 to 3000 hPa.

In some embodiments of the method, the one or more solvents comprise at least propylene carbonate. Based on the total weight of the one or more solvents as 100 weight %, preferably at least 90 weight % of the one or more solvents, more preferably at least 95 weight %, more preferably at least 98 weight %, more preferably at least 99 weight %, more preferably at least 99.5 weight %, more preferably at least 99.9 weight % of the one or more solvents are propylene carbonate. More preferably, the one solvent is propylene carbonate. In some embodiments, the contacting in (b.1') is carried out at a temperature T, which may be in the range of 10 to <170°C, wherein T may preferably be in the range of 140 to 160°C, more preferably in the range of 150 to 160°C, or the contacting in (b.1') is carried out at a temperature T, which may be in the range of 102 to 82 K below the boiling point of propylene carbonate, preferably in the range of 92 to 82 K below the boiling point of propylene carbonate. The contacting in (b.1') is preferably carried out under a pressure in the range of 800 to 1200 hPa. Preferably, the process is run under autogenous pressure, wherein the autogenous pressure can be higher than the ambient pressure of the surrounding area caused by the vapor pressure of propylene carbonate at the temperature T at which the process is run. The person skilled in the art can determine and/or adjust the autogenous pressure based on the vapor pressure curve of propylene carbonate at a certain temperature T. The vapor pressure curve of propylene carbonate is known to the person skilled in the art. The autogenous pressure can be reduced by blowing (for example by means of a blow-off valve), preferably to a pressure between the ambient pressure and below 2000 hPa, preferably to a pressure between 1200 hPa and 1800 hPa. Autogenous pressure is the pressure caused by the production system itself in a closed system, for example in the range of 800 to 3000 hPa.

In some embodiments of the method, the one or more solvents contain at least acetophenone. Based on the total weight of the one or more solvents as 100 weight %, preferably at least 90 weight %, more preferably at least 95 weight %, more preferably at least 98 weight %, more preferably at least 99 weight %, more preferably at least 99.5 weight %, more preferably at least 99.9 weight % of the one or more solvents are acetophenone. More preferably, the one solvent is acetophenone. In some embodiments, the contacting in (b.1') is carried out at a temperature T, which may be in the range of 10 to <170°C, wherein T may preferably be in the range of 140 to 160°C, more preferably in the range of 150 to 160°C, or the contacting in (b.1') is carried out at a temperature T, which may be in the range of 62 to 42 K below the boiling point of acetophenone, preferably in the range of 52 to 42 K below the boiling point of acetophenone. The contacting in (b.1') is preferably carried out under a pressure in the range of 800 to 1200 hPa. Preferably, the process is run under autogenous pressure, wherein the autogenous pressure can be higher than the ambient pressure in the surrounding area caused by the vapor pressure of the acetophenone at the temperature T at which the process is run. The person skilled in the art can determine and/or adjust the autogenous pressure based on the vapor pressure curve of acetophenone at a certain temperature T. The vapor pressure curve of acetophenone is known to the person skilled in the art. The autogenous pressure can be reduced by blowing (for example by means of a blow-off valve), preferably to a pressure between the ambient pressure and below 2000 hPa, preferably to a pressure between 1200 hPa and 1800 hPa. Autogenous pressure is the pressure caused by the production system itself in a closed system, for example in the range of 800 to 3000 hPa.

In some embodiments of the method, the one or more solvents comprise at least dimethyl sulfoxide (DMSO), and based on the total weight of the one or more solvents as 100 weight %, preferably at least 90 weight % of the one or more solvents, more preferably at least 95 weight %, more preferably at least 98 weight %, more preferably at least 99 weight %, more preferably at least 99.5 weight %, more preferably at least 99.9 weight % of the one or more solvents are DMSO, and more preferably, the one solvent is DMSO. In some embodiments, the contacting in (b.1') is carried out at a temperature T, which may be in the range of 10 to <170°C, wherein T may preferably be in the range of 140 to 160°C, more preferably in the range of 150 to 160°C, or the contacting in (b.1') is carried out at a temperature T, which may be in the range of 49 to 29 K below the boiling point of DMSO, preferably in the range of 39 to 29 K below the boiling point of DMSO. The contacting in (b.1') is preferably carried out under a pressure in the range of 800 to 1200 hPa. Preferably, the method is run under autogenous pressure, wherein the autogenous pressure can be higher than the ambient pressure in the surrounding area caused by the vapor pressure of DMSO at the temperature T at which the method is run. The person skilled in the art can determine and/or adjust the autogenous pressure based on the vapor pressure curve of DMSO at a certain temperature T. The vapor pressure curve of DMSO is known to the person skilled in the art. The autogenous pressure can be reduced by purge (for example by purge valve), preferably to a pressure between ambient pressure and below 2000 hPa, preferably to a pressure between 1200 hPa and 1800 hPa. Autogenous pressure is the pressure caused by the production system itself in a closed system, for example in the range of 800 to 3000 hPa.

In some embodiments of the method, one or more solvents at least comprise dihydrolevorotatory glucosone (Cyrene), and based on the total weight of the one or more solvents as 100 weight %, preferably at least 90 weight % of the one or more solvents, more preferably at least 95 weight %, more preferably at least 98 weight %, more preferably at least 99 weight %, more preferably at least 99.5 weight %, more preferably at least 99.9 weight % of the one or more solvents are Cyrene, and more preferably, the one solvent is Cyrene. In some embodiments, the contacting in (b.1') is carried out at a temperature T, which may be in the range of 10 to <170°C, wherein T may preferably be in the range of 140 to 160°C, more preferably in the range of 150 to 160°C, or the contacting in (b.1') is carried out at a temperature T, which may be in the range of 86 to 66 K below the boiling point of Cyrene, preferably in the range of 76 to 66 K below the boiling point of Cyrene. The contacting in (b.1) or (b.2') is preferably carried out under a pressure in the range of 800 to 1200 hPa. Preferably, the process is run under autogenous pressure, wherein the autogenous pressure may be higher than the ambient pressure of the surrounding area caused by the vapor pressure of Cyrene at the temperature T at which the process is run. The autogenous pressure can be determined and/or adjusted by a person skilled in the art based on the vapor pressure curve of Cyrene at a certain temperature T. The vapor pressure curve of Cyrene is known to a person skilled in the art. The autogenous pressure can be reduced by blowing (e.g. by means of a blow-off valve), preferably to a pressure between the ambient pressure and below 2000 hPa, preferably to a pressure between 1200 hPa and 1800 hPa. Autogenous pressure is the pressure caused by the production system itself in a closed system, for example in the range of 800 to 3000 hPa.

In some embodiments of the method, the one or more solvents contain at least cyclohexanone, and based on the total weight of the one or more solvents as 100 weight %, preferably at least 90 weight % of the one or more solvents, more preferably at least 95 weight %, more preferably at least 98 weight %, more preferably at least 99 weight %, more preferably at least 99.5 weight %, more preferably at least 99.9 weight % of the one or more solvents are cyclohexanone, and more preferably, the one solvent is cyclohexanone. In some embodiments, the contacting in (b.1') is carried out at a temperature T, which may be in the range of 10 to <170°C, wherein T is preferably in the range of 140 to 155°C, more preferably in the range of 145 to 150°C, or the contacting in (b.1') is carried out at a temperature T, which may be in the range of 16 to 1 K below the boiling point of cyclohexanone, preferably in the range of 11 to 6 K below the boiling point of cyclohexanone. The contacting in (b.1') is preferably carried out under a pressure in the range of 800 to 1200 hPa. Preferably, the method is operated under autogenous pressure, wherein the autogenous pressure can be higher than the ambient pressure of the surrounding area caused by the vapor pressure of cyclohexanone at the temperature T when the method is operated. The person skilled in the art can determine and/or adjust the autogenous pressure based on the vapor pressure curve of cyclohexanone at a certain temperature T. The vapor pressure curve of cyclohexanone is known to the person skilled in the art. The autogenous pressure can be reduced by blowing (for example by a blow-off valve), preferably to a pressure between the ambient pressure and below 2000 hPa, preferably to a pressure between 1200 hPa and 1800 hPa. Autogenous pressure is the pressure caused by the production system itself in a closed system, for example in the range of 800 to 3000 hPa.

In some embodiments of the method, ethyl benzoate and butyl benzoate are excluded as one or more solvents.

In some embodiments of the method, the solvent system comprises GVL, wherein preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 98 wt%, more preferably in the range of 99 to 100 wt% of the solvent system is composed of GVL, based on the total weight of the solvent system as 100 wt%. In these embodiments, the contacting in (b.1') is carried out at a temperature T, which may be in the range of 10 to <170°C, wherein T may preferably be in the range of 140 to 160°C, more preferably in the range of 150 to 160°C, or the contacting in (b.1') is carried out at a temperature T, which may be in the range of 65 to 45 K below the boiling point of GVL, preferably in the range of 55 to 45 K below the boiling point of GVL. The contacting in (b.1') is preferably carried out at a pressure in the range of 800 to 1200 hPa. Preferably, the process is operated under autogenous pressure, wherein the autogenous pressure can be higher than the ambient pressure in the surrounding area caused by the steam pressure of the GVL at the temperature T at which the process is operated. The person skilled in the art can determine and/or adjust the autogenous pressure based on the steam pressure curve of the GVL at a certain temperature T. The steam pressure curve of the GVL is known to the person skilled in the art. The autogenous pressure can be reduced by blowing (e.g. by means of a blow-off valve), preferably to a pressure between the ambient pressure and below 2000 hPa, preferably to a pressure between 1200 hPa and 1800 hPa. The autogenous pressure is the pressure caused by the production system itself in a closed system, e.g. in the range of 800 to 3000 hPa.

Preferably, the number average molecular weight Mn of the polyalkylene terephthalate-based polymer of the colorant-reduced polymeric material obtained in (b) is greater than or at least equal to the Mn of the polyalkylene terephthalate-based polymer contained in the polymeric material provided in (a). Preferably, the dispersity Mw/Mn (mass average molecular weight Mw divided by the number average molecular weight Mn) of the polyalkylene terephthalate-based polymer of the colorant-reduced polymeric material obtained in (b) is in the range of 70 to 95%, preferably in the range of 75 to 90%, of the dispersity Mw/Mn of the polyalkylene terephthalate-based polymer contained in the polymeric material (100%) provided in (a).

Depolymerization in ( c ) In some embodiments of the method, the depolymerization in (c) is carried out by a method selected from the group consisting of alcoholysis, glycolysis, hydrolysis, aminolysis, aminolysis and a mixture of two or more of these methods.

In some embodiments of the method, the depolymerization of (c) is carried out by alcoholysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with a _C1 to _C4 alkyl monoalcohol to obtain di(C1 to _C4 alkyl) terephthalate and/or di(C1 to _C4 alkyl) isophthalate and ethylene glycol and/or cyclohexanedimethanol and/or butanediol.

In some embodiments of the process, the _C1 to _C4 alkyl monoalcohol is methanol, wherein dimethyl terephthalate and/or dimethyl isophthalate and ethylene glycol and/or cyclohexanedimethanol and/or butanediol are obtained.

In some embodiments of the method, the depolymerization of (c) is carried out by glycolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with a _C1 to _C6 alkyl diol to obtain bis(hydroxy _C1 to _C6 alkyl) terephthalate and/or bis(hydroxy _C1 to _C6 alkyl) isophthalate and ethylene glycol and/or cyclohexanedimethanol and/or butanediol.

In some embodiments of the method, the _C1 to _C6 alkyl diol is ethylene glycol, wherein bis(hydroxyethylene)terephthalate and/or bis(hydroxyethylene)isophthalate and/or bis(hydroxyC1 to _{C6 alkyl} )isophthalate and ethylene glycol and/or cyclohexanedimethanol and/or butanediol are obtained.

In some embodiments of the method, the depolymerization of (c) is carried out by hydrolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with water, thereby obtaining terephthalic acid (TPA) and/or isophthalic acid and ethylene glycol and/or cyclohexanedimethanol and/or butanediol.

In some embodiments of the method, the depolymerization of (c) is performed by alkaline hydrolysis.

In some embodiments of the method, the hydrolysis is carried out by enzyme-catalyzed hydrolysis, wherein (c) comprises contacting the colorant-reduced polymeric material obtained in (b) with water in the presence of an enzyme, thereby obtaining terephthalic acid (TPA) and/or isophthalic acid and ethylene glycol and/or cyclohexanedimethanol and/or butanediol.

In some embodiments of the method, the depolymerization of (c) is carried out by hydrolysis at a pressure in the range of 30×10 ³ to 120×10 ³ hPa.

In some embodiments of the method, the depolymerization of (c) is carried out by hydrolysis, wherein (c) comprises: (c.1) preparing a melt of the colorant-reduced polymer material, thereby obtaining a melt of the colorant-reduced polymer material; (c.2) contacting the melt of the polymer material obtained in (c.1) with an alkali, preferably an inorganic alkali based on an alkali metal, more preferably sodium hydroxide, potassium hydroxide or a mixture of sodium hydroxide and potassium hydroxide, thereby obtaining an alkaline melt; (c.3) The alkaline melt obtained in (c.2) is brought into contact with water to obtain terephthalate (with corresponding alkali metal cations) and/or isophthalate (with corresponding alkali metal cations) and ethylene glycol and/or cyclohexanedimethanol and/or butanediol.

In some embodiments of the method, the depolymerization of (c) is carried out by aminolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with a monoalkylamine ^R1R2NH2 , wherein ^R1 is a _C1 to _C4 ^alkyl _group , and ^R2 is selected from a hydrogen atom and a _C1 to _C4 alkyl group; thereby obtaining ^R1R2NC (=O)-phenyl-C(=O ^{) NR2R1 ,} wherein the substituent at the phenyl ring is in the para or meta position, and ethylene glycol and/or cyclohexanedimethanol.

In some embodiments of the method, the depolymerization of (c) is carried out by aminolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with ammonia (NH ₃ ) to obtain H ₂ NC(═O)-phenyl-C(═O)NH ₂ , wherein the substituent at the phenyl ring is in the para- or meta-position, and ethylene glycol and/or cyclohexanedimethanol; wherein the ammonia is provided in a solvent-free form or dissolved in a solvent, wherein the solvent is preferably one or more of glycerol, a diol (preferably a C ₁ to C ₆ alkyl diol), an alcohol (preferably a C ₁ to C ₄ alkyl monoalcohol).

Transesterification of ( c ) In some embodiments of the method, the transesterification of (c) is carried out by an acid- or base-catalyzed reaction with an alcohol, wherein "acid" includes Lewis acid and Brönsted acid, and "base" includes Lewis base and Brönsted base, as known to those skilled in the art.

In some embodiments of the method, one or more catalysts containing metal cations are used, wherein the metal is preferably titanium or tin.

In some embodiments of the method, the alcohol is R ³ —OH, wherein R ³ is a linear or branched C ₂ to C ₁₂ alkyl residue.

In some embodiments, the transesterification product is di( _C2 to _C12 alkyl) terephthalate and/or di( _C2 to _C12 alkyl) isophthalate and ethylene glycol and/or cyclohexanedimethanol.

In some embodiments of the method, the alcohol is selected from the group consisting of 2-propylheptanol, 2-ethylhexanol, isopropanol, isononanol, pentanol, butanol, isomers of these alcohols, and mixtures of two or more thereof.

Reaction conditions, catalysts, etc. used for the types of reactions described above are well known to those skilled in the art; see, for example, Raheem et al., Journal of Cleaner Production 225 (2019) 1052e1064, Paszun et al., Ind. Eng. Chem. Res. 1997, 36, 1373, and Barnard et al., Green Chem., 2021, 23, 3765-3789.

Polyalkylene terephthalate-based polymers "Polyalkylene terephthalate-based polymers" are composed of oxyethylene units or oxybutylene units and oxyterephthalyl units, wherein in the case of oxyethylene units, the oxyterephthalyl units are replaced by oxyisophthalyl units in the range of 0 to 5 mol % and/or the oxyethylene units are replaced by oxymethylenecyclohexenemethylene units in the range of 0 to 49 mol %.

Preferably, the polyalkylene terephthalate-based polymer is selected from the group consisting of polyethylene terephthalate (PET), poly(ethylene terephthalate-co-1,4-cyclohexylene dimethylene terephthalate) (PETG), poly(ethylene terephthalate-co-ethylene isophthalate) (PETI), polybutylene terephthalate (PBT) and a mixture of two or three of these polymers, or the polyalkylene terephthalate-based polymer is selected from the group consisting of polyethylene terephthalate (PET), poly(ethylene terephthalate-co-ethylene isophthalate) (PETI), polybutylene terephthalate (PBT) and a mixture of two or three of these polymers.

In some embodiments, the polyalkylene terephthalate-based polymer comprises at least 80 wt%, preferably at least 85 wt%, preferably at least 90 wt%, preferably at least 95 wt%, preferably at least 96 wt%, preferably at least 97 wt% of PET, based on the total weight of the polyalkylene terephthalate-based polymer being 100 wt%, and/or preferably, and based on the total weight of the polyalkylene terephthalate-based polymer being 100 wt%, comprises at most 20 wt%, preferably at most 15 wt%, preferably at most 10 wt%, preferably at most 5 wt%, preferably at most 4 wt%, preferably at most 3 wt%, preferably at most 2 wt%, preferably at most 1 wt% of PETI.

In some embodiments, the "polyalkylene terephthalate-based polymer" includes or is a polyester based on 1,4-butanediol or 1,2-ethylene glycol, and is more preferably a polyester 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-ethylene glycol and terephthalic acid (polyethylene terephthalate, PET), a copolymer of 1,4-butanediol, adipic acid and terephthalic acid (polybutylene adipate terephthalate, PBAT), a polymer of 1,2-ethylene glycol and 2,5-furandicarboxylic acid (polyethylene furanoate, PEF), and a mixture of two or more of these (co)polymers.

More preferably, the "polyalkylene terephthalate-based polymer" comprises at least PET and/or PBT, and more preferably, the polyester is PET or PBT or a mixture of PET and PBT.

More preferably, the polyalkylene terephthalate-based polymer comprises or is PET.

In some embodiments of the method, the colored polymeric material originates from bottles and/or textiles. In some embodiments, the colored polymeric material originates from textiles such as clothing, wherein the textiles are preferably subjected to a sorting process before the polymeric material is subjected to the method according to the present invention. The sorting process preferably comprises one or more NIR sorting steps, wherein the textiles are analyzed by near infrared (NIR) spectroscopy and, based on the results of the analysis, are sorted based on their composition. Therefore, the polymeric material subjected to the method according to the present invention is preferably pre-sorted, more preferably NIR pre-sorted textiles. The textiles are preferably subjected to size reduction, more preferably to shearing and/or shredding steps. Therefore, the polymeric material subjected to the method according to the present invention is preferably a pre-sorted, more preferably NIR pre-sorted, and/or size-reduced, more preferably sheared and/or shredded textile. In some embodiments, the polymeric material subjected to the method according to the present invention is preferably a pre-sorted, more preferably NIR pre-sorted, and/or size-reduced, more preferably sheared and/or shredded textile, and the content of PA6 is less than 10 wt%, more preferably less than 5 wt%, more preferably less than 4 wt%, more preferably less than 3 wt%, more preferably less than 2 wt%, more preferably less than 1 wt%, based on the total weight of the polymeric material as 100 wt%. Reducing the content of PA in the textile can provide improved quality of the obtained polyester, especially polymers based on polyalkylene terephthalate.

Second polymer ( iii ) In some embodiments of the method, the second polymer (iii) is selected from the group consisting of: polypropylene (PP); polyethylene (PE); polyamide (PA), preferably PA6 and/or PA66; natural polymers, preferably cotton, viscose, linen and mixtures of two or more thereof.

Third polymer ( iv ) In some embodiments of the method, the third polymer (iv) is an elastic fiber.

In some embodiments of the method, the elastic fiber comprises one or more polyurethane-based elastic fibers and/or one or more polyester-based elastic fibers, preferably consisting of them, more preferably, the elastic fiber comprises one or more polyurethane-based elastic fibers, preferably consisting of them, wherein each of the elastic fibers, based on the total weight of the elastic fiber as 100 weight%, preferably at least 40 weight%, more preferably at least 45 weight%. , preferably at least 50 wt %, better at least 55 wt %, better at least 60 wt %, better at least 65 wt %, better at least 70 wt %, better at least 75 wt %, better at least 80 wt %, better at least 85 wt %, better at least 90 wt %, better at least 95 wt %, better at least 99.9 wt % of the elastic fibers are one or more polyurethane-based elastic fibers.

The one or more polyurethane-based elastic fibers are preferably polyurethane-based (block) copolymers. The (block) copolymer based on polyurethane is preferably a (block) copolymer of polyurethane and one or more polyethers selected from the group consisting of polyethylene glycol, polytetrahydrofuran, copolymers of 2-methyltetrahydrofuran and tetrahydrofuran, and copolymers of 3-methyltetrahydrofuran and tetrahydrofuran, wherein the (block) copolymer based on polyurethane is more preferably a (block) copolymer of polyurethane and polyethylene glycol or a (block) copolymer of polyurethane and polytetrahydrofuran, wherein more preferably, in each of these (block) copolymers of polyurethane, the polyurethane content is at least 85% by weight, based on 100% by weight of the total weight of the (block) copolymer. The expression "(block) copolymer" means copolymers and block copolymers, wherein block copolymers are preferred. (Block) copolymers of polyurethane and one or more polyethers selected from the group consisting of polyethylene glycol, polytetrahydrofuran, copolymers of 2-methyltetrahydrofuran and tetrahydrofuran, copolymers of 3-methyltetrahydrofuran and tetrahydrofuran, in particular when the polyurethane content is at least 85% by weight, based on the total weight of the (block) copolymer being 100% by weight, also known by common names such as "elastic rayon", "elastic fiber", "elastano", "elastam", "elastaan" or "spandex". Brand names also include "Lycra", "Elaspan", "Acepora", "Creora", "INVIYA", "ROICA", "Dorlastan", "Linel" and "ESPA". The polyester-based elastic fiber is preferably a poly(trimethylene terephthalate) (PTT) copolymer, wherein the poly(trimethylene terephthalate) copolymer is more preferably selected from the group of copolyesters synthesized from two or more reactants, each reactant having two functional groups capable of forming ester groups. For example, poly(trimethylene terephthalate) copolymers can be prepared by reacting 1,3-propylene glycol and terephthalic acid and, optionally, one or more comonomers selected from the group consisting of a linear aliphatic dicarboxylic acid having 4 to 12 carbon atoms, a cycloaliphatic dicarboxylic acid having 4 to 12 carbon atoms, a branched aliphatic dicarboxylic acid having 4 to 12 carbon atoms (such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid or their ester-forming equivalents), an aromatic dicarboxylic acid other than terephthalic acid having 8 to 12 carbon atoms (such as phthalic acid, isophthalic acid, dicarboxylic acid or 2,6-naphthalene dicarboxylic acid); linear diols having 2 to 8 carbon atoms other than 1,3-propylene glycol, cyclic diols having 2 to 8 carbon atoms, and branched aliphatic diols having 2 to 8 carbon atoms (such as ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, hexanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propanediol, cyclohexanedimethanol or 1,4-cyclohexanediol), aliphatic ether diols having 4 to 10 carbon atoms, and aromatic ether diols having 4 to 10 carbon atoms (such as hydroquinone bis(2-hydroxyethyl) ether). Alternatively, poly(trimethylene terephthalate) copolymers can be prepared from poly(vinyl ether) glycols (such as divinyl ether glycol, methoxy polyalkylene glycol, diethylene glycol and polyethylene glycol) having a molecular weight below 460 g/mol. The comonomer is present in the copolymer in an amount ranging from 0.5 to 30 mol %, preferably in an amount ranging from 0.5 to 20 mol %. The common name of poly(trimethylene terephthalate) (PTT) copolymers is "Sorona", wherein in some embodiments, Sorona is a copolymer of 1,3-propylene glycol (preferably obtained by forming) and terephthalic acid (TPA) or dimethyl terephthalate (DMT), wherein preferably 20 to 50 wt. %, more preferably 30 to 40 wt. % of the copolymer is based on 1,3-propylene glycol, more preferably 1,3-propylene glycol obtained from renewable resources.

Coloring Agents In some embodiments of the method, the coloring agent is selected from the group consisting of a dye and an optical brightener and a mixture of a dye and an optical brightener.

A "colorant" is a substance which causes a change in the color impression of a material. This includes dyes which absorb in the wavelength interval of visible light (400 to 780 nm) and optical brighteners which amplify the light emission of the material by UV light absorption and visible light emission (by fluorescence), i.e. optical brighteners convert radiation which is invisible to the human eye (<400 nm) into visible fluorescent radiation in the blue-red spectral range (400 to 600 nm). Colorants which can be used or are used to change the color impression of polymeric materials are known to those skilled in the art. In the context of the present invention, the term "dye" means any kind of dye, such as dyes, pigments, dispersions, wherein the dye is, for example, one or more selected from the group consisting of acid dyes, alkaline dyes, direct dyes, disperse dyes, azo dyes, food dyes, solvent dyes, organic dyes, organic pigments, sulfur dyes, mordant dyes and vat dyes. The term "optical brightener" includes optical brighteners, fluorescent brighteners and fluorescent whitening agents.

An overview of colorants for polymeric materials can be found, for example, in the following references: “Dyes and Pigments” Metin Açikyildiz, Kübra Günes, Ahmet Gürses Springer, 2016 (ISBN: 10 : 3319338900); Industrial Organic Pigments - Klaus Hunger, Thomas Heber, Martin U. Schmidt, Friedrich Reisinger, Stefan Wanne Wiley-VCH, 4th edition, 2018 (ISBN: 978-3-527-32608-2); Chemistry and Technology of Natural and Synthetic Dyes and Pigments - Ashis Kumar Samanta, Nasser Awwad, IntechOpen, 2020 (ISBN: 9781789859980, 9781789859973, 9781839687587); Encyclopedia of Color, Dyes, Pigments - Volume 1, Gerhard Pfaff, de Gruyter, 2021 (ISBN: 311058588X); Heinrich Zollinger: Color Chemistry : Syntheses , Properties , and Applications of Organic Dyes and Pigments . 3rd edition. 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, chapters "dyes and pigments" and "dyes, general survey" (ISBN: 9783527303854).

In some embodiments of the method, the obtained polymer material with reduced colorant means that the L*a*b* value of the polymer material with reduced colorant compared to the polymer material provided in (a) changes as follows: The absolute value of a* decreases, 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 is compared with the L*a*b* value of the colored polymer material provided in (a), wherein the L*a*b* value is determined according to DIN 5033 and DIN EN ISO 11664-1.6.

The expression "without regard to color" means that even though materials of each color are usually analyzed separately, the definition given above applies not only to single-color polymeric materials, but also to polymeric materials with multiple colors and mixtures of polymeric material sheets, each of which has its own color or its own mixture of colors.

The above "reduction of colorants" expressed based on the quantitative L*a*b* values can also be visually discerned by eye: the polymeric material provided in (a) has a certain color, wherein the obtained polymeric material is preferably lighter and whiter than the polymeric material obtained from (b), (b.4), (b.2.') or (b6) described herein. This is particularly applicable to all colorants that are not optical brighteners. With respect to the obtained polymeric material, in particular with respect to an optical brightener as a colorant, colorant reduction means that the intensity of the emitted fluorescent radiation (emission) (preferably in the range of 400 to 600 nm) is reduced for the polymeric material obtained in (s) when irradiated with light having a wavelength in the range of 250 to 400 nm, compared to the intensity of the emitted fluorescent radiation (emission) (preferably in the range of 400-600 nm) of the polymeric material provided in (a).

Methods for determining the intensity of the emitted fluorescent radiation are known to those skilled in the art and may be determined, for example, visually using UV light, by fluorescence measurement or by measurement of the quantum yield.

Separation of the second polymer ( iii ) In some embodiments, if the second polymer (iii) is present in the polymer material provided in (a), the method further comprises: (d) separating the second polymer (iii) from the monomers and/or oligomers or transesterification products obtained in (c), thereby obtaining separate monomers and/or oligomers or transesterification products and separate second polymer (iii).

Separation of the third polymer ( iv ) In some embodiments, if the third polymer (iv) is present in the polymer material provided in (a), the method further comprises: separating the third polymer (iv) from the colorant-rich solvent system obtained in (b), (b.4), (b.4.2.), (b.5) and/or (b.2') to obtain a separate third polymer (iv).

The separation of the third polymer, if present in the polymeric material, and the colorant if present, is carried out, for example, by distillation, wherein the solvent system is removed and the remaining residue is further used.

In some embodiments, the method comprises recycling the separated solvent system obtained in one or more of the method steps described above back into the method, optionally after one or more treatment steps.

Aspect 2 - Monomer, oligomer or transesterification product of a polymer based on polyalkylene terephthalate The second aspect of the present invention is related to a monomer, oligomer or transesterification product of a polymer based on polyalkylene terephthalate, which is obtained by or can be obtained by the method of the first aspect, preferably the method of step (d). All details and embodiments disclosed in the above section on the first aspect and alternative embodiments are also applicable to the second aspect.

Aspect 3 - Repolymerization of monomers, oligomers and / or transesterification products In a fourth aspect, the present invention relates to a method, preferably according to the first aspect, which comprises the additional step of : - converting, preferably polymerizing, monomers, oligomers or transesterification products of polyalkylene terephthalate-based polymers obtained or obtainable according to the method of the first aspect to obtain one or more polymers or polymer products.

All details and embodiments disclosed in the above section regarding the first aspect and alternative embodiments also apply to the third aspect.

Preferably, one or more polymers are polyalkylene terephthalate-based polymers. "Polyalkylene terephthalate-based polymers" consist of oxyethylene units or oxybutylene units and oxyterephthalyl units, wherein in the case of oxyethylene units, the oxyterephthalyl units are replaced by oxyisophthalyl units in the range of 0 to 5 mol % and/or the oxyethylene units are replaced by oxymethylenecyclohexenemethylene units in the range of 0 to 49 mol %. Preferably, the polyalkylene terephthalate-based polymer is selected from the group consisting of polyethylene terephthalate (PET), poly(ethylene terephthalate-co-1,4-cyclohexylene dimethylene terephthalate) (PETG), poly(ethylene terephthalate-co-ethylene isophthalate) (PETI), polybutylene terephthalate (PBT) and a mixture of two or more of these polymers, or the polyalkylene terephthalate-based polymer is selected from the group consisting of polyethylene terephthalate (PET), poly(ethylene terephthalate-co-ethylene isophthalate) (PETI), polybutylene terephthalate (PBT) and a mixture of two or three of these polymers.

In some embodiments, the "polyalkylene terephthalate-based polymer" is a polyester based on 1,4-butanediol or 1,2-ethylene glycol, and more preferably a polyester 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-ethylene glycol and terephthalic acid (polyethylene terephthalate, PET), a copolymer of 1,4-butanediol, adipic acid and terephthalic acid (polybutylene adipate terephthalate, PBAT), a polymer of 1,2-ethylene glycol and 2,5-furandicarboxylic acid (polyethylene furanoate, PEF), and a mixture of two or more of these (co)polymers.

More preferably, the "polyalkylene terephthalate-based polymer" comprises at least PET and/or PBT, and more preferably, the polyester is PET or PBT or a mixture of PET and PBT.

More preferably, the polyalkylene terephthalate-based polymer comprises or is PET.

Preferably, the polymer product is a textile, fiber, packaging, plastic, preferably: - a part of an automobile; preferably a cylinder head cover, an engine cover, a housing for a supercharged air cooler, a supercharged air cooler baffle, an intake pipe, an intake manifold, a connector, a gear, a fan wheel, a cooling water tank, a housing, a housing part of a heat exchanger, a coolant cooler, a supercharged air cooler, a thermostat, a water pump, a radiator, a fastening part, a battery system part of an electric vehicle, an instrument Dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper guards, decorative grilles, cover strips, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushions or coatings; -  Cloth; preferably shirts, trousers, pullovers, boots, shoes, soles, leggings or jackets; - Electrical parts; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foils, wires, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, bobbins, lamps, diodes, LEDs, transistors, connectors, regulators, integrated circuits (ICs), processors, controllers, memories, sensors, micro switches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, spacers, screws, strips, slide-in guides, screws, nuts, film hinges, spring hooks (snap-on) or spring tongues for electrical or electronic components; - Consumer products, agricultural products or pharmaceutical products; preferably tennis string, climbing rope, bristles, brushes, artificial grass, 3D printing filaments, grass trimmers, zippers, hook and loop fasteners, paper machine fabrics, extruded coatings, fishing lines, fishing nets, marine lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyor belts, sliding bearings , rollers, wheels, gears, rollers, ring gears, screws and spring dampers, hoses, pipes, cable sheathing, sockets, switches, cable ties, fan wheels, carpets, cosmetic cases or bottles, mattresses, cushions, insulating materials, cleaners, dishwashing tablets or powders, shampoos, body washes, shower gels, soaps, fertilizers, fungicides or insecticides; -  Packaging for the food industry; preferably single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxially stretched film or laminated film; or -  Part of a structure; preferably a rotor blade, insulation material, frame, shell, wall, coating or separator wall.

The preferred polymerization step for converting the monomer, oligomer or transesterification product of the polyalkylene terephthalate-based polymer obtained by repolymerization into the polyalkylene terephthalate-based polymer may comprise one or more synthesis steps and may be carried out by known syntheses and techniques familiar to those skilled in the art (see, for example, Ullmann's Encyclopedia of Industrial Chemistry, chapter "Polyesters", Wiley-VCH Verlag GmbH & Co. KGaA. 2018, 10.1002/14356007.a21_227.pub2).

Aspect 4 - Conversion of the second polymer ( iii ) and / or the third polymer ( iv ) In the fourth aspect, the present invention relates to a method, preferably according to the first aspect, which comprises the further step of: - converting the separated second polymer (iii) and/or the separated third polymer (iv) obtainable by or by the method of the first aspect, preferably the separated second polymer (iii) obtained or obtainable from step (d) and/or the separated third polymer (iv) obtained or obtainable from any one of steps (b), (b.4), (b.4.2.), (b.5) and (b.2') to obtain one or more monomers, polymers or polymer products.

All details and embodiments disclosed in the above section regarding the first aspect and alternative embodiments also apply to the fourth aspect.

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

Preferably, the polymer and/or polymer product is or is part of: - a part of a car; preferably a cylinder head cover, an engine cover, a casing for a supercharged air cooler, a supercharged air cooler baffle, an intake pipe, an intake manifold, a connector, a gear, a fan wheel, a cooling water tank, a casing, a casing part of a heat exchanger, a coolant cooler, a supercharged air cooler, a thermostat, a water pump, a radiator, a fastening part, a battery system part of an electric car, an instrument Dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper guards, decorative grilles, cover strips, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushions or coatings; -  Cloth; preferably shirts, trousers, pullovers, boots, shoes, soles, leggings or jackets; - Electrical parts; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foils, wires, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, bobbins, lamps, diodes, LEDs, transistors, connectors, regulators, integrated circuits (ICs), processors, controllers, memories, sensors, micro switches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, spacers, screws, strips, slide-in guides, screws, nuts, film hinges, spring hooks (snap-on) or spring tongues for electrical or electronic components; - Consumer products, agricultural products or pharmaceutical products; preferably tennis string, climbing rope, bristles, brushes, artificial grass, 3D printing filaments, grass trimmers, zippers, hook and loop fasteners, paper machine fabrics, extruded coatings, fishing lines, fishing nets, marine lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyor belts, sliding bearings , rollers, wheels, gears, rollers, ring gears, screws and spring dampers, hoses, pipes, cable sheathing, sockets, switches, cable ties, fan wheels, carpets, cosmetic cases or bottles, mattresses, cushions, insulating materials, cleaners, dishwashing tablets or powders, shampoos, body washes, shower gels, soaps, fertilizers, fungicides or insecticides; -  Packaging for the food industry; preferably single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxially stretched film or laminated film; or -  Part of a structure; preferably a rotor blade, insulation material, frame, shell, wall, coating or separator wall.

Preferably, the content of the separated second polymer (iii) and/or the separated third polymer (iv) in the polymer and/or the polymer product is 1 wt% or more, preferably 2 wt% or more, more preferably 5 wt% or more, more preferably 15 wt% or more, more preferably 30 wt% or more, more preferably 40 wt% or more, more preferably 60 wt% or more, more preferably 80 wt% or more, more preferably 90 wt% or more, more preferably 95 wt% or more; and/or The content of the separated second polymer in the polymer and/or the polymer product is 100 wt% or less, preferably 95 wt% or less, more preferably 90 wt% or less, more preferably 50 wt% or less, more preferably 25 wt% or less, more preferably 10 wt% or less; and Preferably, the content is determined based on identity preservation and/or isolation and/or mass balance and/or a book and patent application scope regulatory chain model, preferably based on mass balance, preferably International Sustainability and Carbon Certification (ISCC) standards.

The conversion step of obtaining monomers, polymers or polymer products from the separated second polymer (iii) and/or the separated third polymer (iv) may comprise one or more synthesis steps and may be performed by known syntheses and techniques known to those skilled in the art. Those skilled in the art who independently assess the novelty and inventiveness of the steps in the independent patent application scope, preferably those skilled in the art who perform one or more conversion steps are from one or more technical fields of pyrolysis, gasification, re-monomerization, depolymerization, synthesis, production of monomers, polymers and polymer compounds and/or their further processing (e.g. extrusion, injection molding). Examples of one or more conversion steps are described in the following: "Industrial Organic Chemistry", Volume 3, Wiley-VCH, 1997, ISBN: 978-3-527-28838-0, "Kunststoffhandbuch", Volume 11, 17 sub-volumes, Carl Hanser Verlag; in particular Volume 6, "Polyamide", 1st edition, 1966, Volume 7, "Polyurethane", 3rd edition, 1993, and Volume 8, "Polyester", 2nd edition 1973; "Industrial Organic Chemistry", Volume 3, Wiley-VCH, 1997, ISBN: 978-3-527-28838-0, "Injection Molding Reference Guide", 4th edition, CreateSpace Independent Publishing Platform, 2011, ISBN: 978-1466407824, EP 0989146 A1, EP 1460094 A1, WO 2006034800 A1, EP 1529792 A1, WO 2006042674 A1, EP 0364854 A2, US 5506275 A, EP 0897402 A1, WO 2015082316 A1, WO 2021021855 A1, WO 2021126938 A1, WO 2021021902 A1, WO 2021092311 A1, WO 2008155271 A1, WO 2013139827 A1, each of which is incorporated herein by reference.

The present invention is further described by the following embodiments and combinations of embodiments as indicated by respective dependencies and cross-references. In particular, it should be noted that in each case where a series of embodiments are mentioned, for example, in the context of a term such as "such as any one of Embodiments 1 to 4...", each embodiment in this scope is meant to be explicitly disclosed to those skilled in the art, that is, the wording of this term is understood by those skilled in the art to be synonymous with "such as any one of Embodiments 1, 2, 3 and 4..." 1. A method for recycling a colored polymeric material, wherein the colored polymeric material comprises (i) a poly(alkylene terephthalate)-based polymer poly[ _CH2 ] _x terephthalate, wherein x is an integer in the range of 1 to 4; (ii) a coloring agent; and optionally (iii) a second polymer different from the poly(alkylene terephthalate)-based polymer of (i); and optionally (iv) a third polymer different from the poly(alkylene terephthalate)-based polymer of (i) and different from the second polymer of (iii), the method comprising: (a) providing a colored polymeric material and a solvent system; (b) The colored polymeric material provided in (a) is contacted with the solvent system provided in (a) under conditions that allow the removal of the colorant but do not allow the poly(alkylene terephthalate)-based polymer to dissolve, thereby obtaining a solvent system that is rich in colorant compared to the solvent system provided, and a polymeric material with reduced colorant compared to the colored polymeric material provided in (a); (c) depolymerizing or transesterifying the polymeric material with reduced colorant obtained in (b); thereby obtaining monomers and/or oligomers or transesterification products. 2. The method of embodiment 1, wherein (b) comprises: (b.1) providing the colored polymeric material in a first container and providing the solvent system in a second container; wherein the first container and the second container are spatially separated from each other but allow gas and fluid communication between each other; (b.2) forming a gas flow including at least a portion of the solvent system, and removing the gas flow from the second container; (b.3) separating the solvent system in liquid form from the gas flow at a position outside the second container (also outside the first container) to obtain a solvent system in liquid form; (b.4) contacting the colored polymeric material in the first container with the solvent system in liquid form, the solvent system having been separated from the gas flow in (b.3), Thereby, a solvent system is obtained which is enriched in colorant and, if appropriate, in a third polymer (iv) compared to the solvent system provided in (a), and a polymeric material which is reduced in colorant and, if appropriate, in a third polymer (iv) compared to the colored polymeric material provided in (a) and comprises the polyalkylene terephthalate-based polymer (i) and, if appropriate, the second polymer (iii). 3. The method of embodiment 2, wherein (b.2) comprises: (b.2.1) heating the solvent system to a temperature at least equal to or higher than the boiling temperature of the solvent system; (b.2.2) obtaining a gas stream comprising at least a portion of the solvent system. 4. The method of embodiment 2 or 3, wherein an inert gas is additionally applied, the inert gas forming part of a gas stream comprising at least part of the solvent system. 5. The method of any one of embodiments 2 to 4, wherein (b.2) comprises: (b.2.1') heating the solvent system to a temperature T which is at most 3 K below the boiling temperature of the solvent system; so that a solvent system with an elevated temperature is obtained; (b.2.2') contacting the solvent system with an elevated temperature with an inert gas, preferably passing the inert gas through the solvent system with an elevated temperature, so that a gas stream comprising at least part of the solvent system is formed. 6. A method as described in any one of Examples 2 to 5, wherein (b.3) comprises: (b.3.1) transferring the gas flow from the second container to a position outside the second container (also outside the first container); (b.3.2) separating the portion of the solvent system contained in the gas flow in liquid form from the gas flow at a position outside the second container (also outside the first container) to obtain a solvent system in liquid form. 7. A method as described in any one of Examples 2 to 6, wherein (b.4) comprises: (b.4.1) transferring the liquid form of the solvent system obtained in (b.3.2) to the colored polymer material in the first container; (b.4.2) contacting the colored polymer material in the first container with the liquid form of the solvent system, thereby obtaining a solvent system that is rich in colorant and, if appropriate, a third polymer compared to the solvent system provided in (a), and a polymer material, which has a reduced colorant and, if appropriate, a reduced third polymer compared to the colored polymer material provided in (a) and comprises the polyalkylene terephthalate-based polymer and, if appropriate, the second polymer. 8. The method of any one of Examples 2 to 7, wherein the first container containing the polymer material and the second container containing the solvent system are spatially separated from each other, wherein the first container containing the polymer material is arranged above the second container containing the solvent system. 9. The method of Example 7 or 8, wherein (b.4.2) comprises contacting the colored polymer material with the liquid form of the solvent system of (b.4.1), wherein the liquid form of the solvent system is dripped onto the colored polymer material. 10. The method of any one of Examples 2 to 9, wherein the inert gas is selected from the group consisting of argon, helium, neon, nitrogen and a mixture of two or more of these inert gases, preferably comprising at least nitrogen, and more preferably, the inert gas is nitrogen. 11. The method of any one of embodiments 2 to 10, wherein the inert gas is directed through the solvent system at a flow rate in the range of 1 to 150 liters per hour, or the inert gas is passed along the surface of the solvent system at a flow rate in the range of 1 to 150 liters per hour. 12. A method as in any one of Examples 2 to 11, further comprising: (b.5) removing the coloring agent-rich and optionally third polymer-rich solvent system obtained in (b.4) or (b.4.2) from the polymeric material (i.e. also from the first container) and recirculating it to the second container containing the solvent system, preferably by dripping it into the second container containing the solvent system (causing the solvent system obtained in (b.4) or (b.4.2) to drip into the second container containing the solvent system). 13. A method as in any one of Examples 2 to 12, wherein (b.2), (b.3) and (b.4), preferably (b.2), (b.3), (b.4) and (b.5) are performed in a continuous mode. 14. A method as in any one of Examples 2 to 13, further comprising: (b.6) at least partially removing the polymer material obtained in (b.4) or (b.4.2), thereby obtaining a polymer material having a reduced colorant and a reduced third polymer (iv) as appropriate compared to the colored polymer material provided in (a) and comprising the polyalkylene terephthalate-based polymer and the second polymer as appropriate. 15. The method of Example 14 further comprises: (b.7) replacing at least part of the polymer material removed in (b.6) with fresh colored polymer material without replacing the solvent system provided in (a), wherein the fresh colored polymer material comprises a polymer based on polyalkylene terephthalate, a colorant, a second polymer as appropriate, and a third polymer as appropriate, and repeating steps (b.2), (b.3) and (b.4), and optionally repeating (b.5); wherein steps (b.6) and (b.7) are preferably repeated at least once, preferably within a range of one to at least 10 times (batch mode); or wherein steps (b.6) and (b.7) are performed continuously (sweep mode). 16. The method of any one of embodiments 2 to 15, wherein additional fresh solvent system is added in an amount ranging from 1 to 50 wt %, based on the total weight of the solvent system provided in (a) being 100 wt %, wherein the addition is performed discontinuously (batch mode) or continuously (sweep mode). 17. A method as in Example 1, wherein (b) comprises: (b.1') contacting the colored polymer material of (a) with a solvent system at a temperature T of <170°C, thereby obtaining a solvent system that is rich in colorant and, optionally, rich in a third polymer (iv) compared to the solvent system provided in (a), and a polymer material that has reduced colorant and, optionally, reduced third polymer (iv) compared to the colored polymer material provided in (a); (b.2') optionally separating the polymer material from the solvent system, wherein the colorant and, optionally, reduced third polymer (iv) in the polymer material and comprises the polyalkylene terephthalate-based polymer. 18. The method of embodiment 17, wherein the contacting in (b.1') is carried out at a temperature T in the range of 10 to <170° C., preferably in the range of 110 to 165° C., more preferably in the range of 120 to 150° C. 19. The method of embodiment 17 or 18, wherein (b.1') is carried out at a pressure in the range of 800 to 200,000 hPa. 20. The method of any one of embodiments 1 to 19, wherein the solvent system comprises one or more solvents, wherein the solvent system (s.1) has Hansen solubility parameters relative to - energy from dispersion forces between molecules (δD _ss ), - energy from dipole intermolecular forces between molecules (δP _ss ) and - energy from hydrogen bonds between molecules (δH _ss ), which satisfy Equation 1 (11) ² ≥ 4(δD _ss -17.5) ² + (δP _ss -7.5) ² + (δH _ss -7.5) ² [Equation 1]. 21. The method of any one of embodiments 1 to 20, wherein the solvent system comprises one or more solvents, wherein the solvent system (s.1a) has Hansen solubility parameters relative to - energy from dispersion forces between molecules (δD _ss ), - energy from dipole intermolecular forces between molecules (δP _ss ) and - energy from hydrogen bonds between molecules (δH _ss ), which satisfy Equation 2 (8.8) ² ≥ 4(δD _ss -20) ² + (δP _ss -11.8) ² + (δH _ss -4.5) ² [Equation 2]. 22. The method of any one of embodiments 1 to 21, wherein (s.2) each solvent of the solvent system has a boiling point of at least 150°C, preferably at least 160°C at 1013 hPa. 23. The method of any one of embodiments 1 to 22, wherein (s.3) does not include a solvent having a functional group selected from the group consisting of a hydroxyl group (OH), an amine group (NH ₂ ), a carboxyl group (COOH) and a thiol group (SH). 24. The method of any one of embodiments 1 to 23, wherein based on the total weight of the solvent system as 100% by weight, at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, more preferably in the range of 99 to 100% by weight of the solvent system consists of two or more solvents. 25. The method of any one of embodiments 1 to 24, wherein based on the total weight of the solvent system as 100 wt%, at least 90 wt%, preferably at least 95 wt%, more preferably at least 98 wt%, more preferably in the range of 99 to 100 wt% of the solvent system is composed of one solvent, and the one solvent satisfies equations 1 and/or 2. 26. The method of any one of embodiments 1 to 25, wherein one or more solvents of the solvent system are selected from the group consisting of: N,N-dimethylbenzamide, N,N-dimethylphenylacetamide, 1,4-benzoquinone, acetophenone, dimethyl terephthalate, 1,3,5-trimethoxybenzene, 2-phenylacetophenone, N-methylcaprolactam, methyl benzoate, methyl-4-methoxybenzoate, butyl carbonate, propylene glycol dibenzoate, N-ethylpyrrolidone, benzophenone, diphenylmethyl malonate, N-ethyl-caprolactam amide, 2-(5-oxotetrahydrofuran-3-yl)acetate methyl ester (FAME), propiophenone, N-methoxypropyl-pyrrolidone, 1,4-cyclohexanedione, cyclohexane-carbonate, N-methoxyethyl-pyrrolidone, N,N-diethylphenylacetamide, phenyl acetate, 1-(2-hydroxyethyl)pyrrolidin-2-one acetate (HEPAc), N,N-diethylbenzamide, isopropyl-benzene formate, cyclohexyl phenyl ketone, ethyl phenylacetate, phenylacetic acid ester, N-methyl-phenoxy phthalate, benzyl-propionate, benzyl acetate, neopentyl-diol-dibenzoate, tetrahydrofuran acetate, N-methyl-imidazole, benzyl butyrate, 2-pyrrolidone, 2-phenoxyethanol propionate, 2-phenoxyethyl isobutyrate, N,N-dipropylbenzamide, N,N-dimethylacetamide, N,N-diethylacetamide, amide, dihydro-L-glucose ketone (Cyrene), propyl carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-hydroxypyrrolidine-3-carboxylate (MMOC), γ-valerolactone (GVL), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-hydroxypentanoate (Rhodiasolv Polarclean), caprolactone, ethyl phenylacetate, methyl phenylacetate, benzyl benzoate, N,N-dimethyllactamide (Agnique AMD 3L) and dimethyl sulfoxide (DMSO). 27. The method of any one of embodiments 1 to 26, wherein one or more solvents of the solvent system are selected from the group consisting of dihydro-levorotatory glucosone (Cyrene), propyl carbonate, caprolactone, dimethyl isosorbide, N-butyl pyrrolidone, tert-butyl pyrrolidone, methyl-1-methyl-5-hydroxypyrrolidine-3-carboxylate (MMOC), γ-valerolactone (GVL), δ-valerolactone, γ-butyrolactone, 5-(dimethylamino)-2-methyl-5-hydroxypentanoic acid methyl ester (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenyl acetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate and dimethyl sulfoxide (DMSO). 28. The method of any one of embodiments 1 to 27, wherein one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopentylpyrrolidine-3-carboxylate (MMOC), delta-valerolactone, gamma-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopentylvalerate (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate and GVL. 29. The method of any one of embodiments 1 to 28, wherein one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopentylpyrrolidine-3-carboxylate (MMOC), delta-valerolactone, gamma-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopentylvalerate (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, and propyl benzoate. 30. The method of any one of embodiments 1 to 29, wherein one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidine-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polarclean), phenylethyl acetate and GVL. 31. The method of any one of embodiments 1 to 30, wherein one or more solvents of the solvent system are selected from the group consisting of propyl carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidine-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv® Polarclean) and phenylethyl acetate. 32. The method of any one of embodiments 1 to 31, wherein the one or more solvents are selected from the group consisting of gamma valerolactone (GVL), N-butylpyrrolidone (NBP), propyl carbonate, dimethyl sulfoxide acetophenone (DMSO), dihydrolevoglucose ketone (Cyrene), cyclohexanone, and mixtures of two or more thereof, or selected from the group consisting of N-butylpyrrolidone (NBP), propyl carbonate, dimethyl sulfoxide acetophenone (DMSO), dihydrolevoglucose ketone (Cyrene), cyclohexanone, and mixtures of two or more thereof. 33. The method of any one of embodiments 1 to 32, wherein the one or more solvents are selected from the group consisting of GVL, NBP, propyl carbonate, acetophenone, DMSO, and mixtures of two or more thereof, or selected from the group consisting of NBP, propyl carbonate, acetophenone, DMSO, and mixtures of two or more thereof. 34. The method of any one of embodiments 1 to 33, wherein the one or more solvents are selected from the group consisting of GVL, NBP, propyl carbonate, acetophenone, and mixtures of two or more thereof, or selected from the group consisting of NBP, propyl carbonate, acetophenone, and mixtures of two or three thereof. 35. The method of any one of Examples 1 to 34, wherein the one or more solvents at least comprise N-butylpyrrolidone (NBP), based on the total weight of the one or more solvents as 100 wt%, preferably at least 90 wt% of the one or more solvents, more preferably at least 95 wt%, more preferably at least 98 wt%, more preferably at least 99 wt%, more preferably at least 99.5 wt%, more preferably at least 99.9 wt% of the one or more solvents are NBP, more preferably, the one solvent is NBP; or wherein the one or more solvents at least comprise propylene carbonate, based on the total weight of the one or more solvents as 100 wt%, preferably at least 90 wt% of the one or more solvents , preferably at least 95 wt %, more preferably at least 98 wt %, more preferably at least 99 wt %, more preferably at least 99.5 wt %, more preferably at least 99.9 wt % of the one or more solvents are propylene carbonate, more preferably, the one solvent is propylene carbonate; or wherein the one or more solvents at least comprise acetophenone, based on the total weight of the one or more solvents as 100 wt %, preferably at least 90 wt % of the one or more solvents, more preferably at least 95 wt %, more preferably at least 98 wt %, more preferably at least 99 wt %, more preferably at least 99.5 wt %, more preferably at least 99.9 wt % of the one or more solvents are acetophenone, more preferably, the one solvent is acetophenone. or wherein the one or more solvents at least comprise dimethyl sulfoxide (DMSO), based on the total weight of the one or more solvents as 100% by weight, preferably at least 90% by weight of the one or more solvents, more preferably at least 95% by weight, more preferably at least 98% by weight, more preferably at least 99% by weight, more preferably at least 99.5% by weight, more preferably at least 99.9% by weight of the one or more solvents are DMSO, and more preferably, the one solvent is DMSO; or wherein the one or more solvents at least comprise dihydro-L-glucose ketone (Cyrene), based on the total weight of the one or more solvents as 100% by weight, preferably at least 90% by weight of the one or more solvents, more preferably at least 98% by weight, more preferably at least 99% by weight, more preferably at least 99.5% by weight, more preferably at least 99.9% by weight of the one or more solvents are DMSO, and more preferably, the one solvent is DMSO. At least 95% by weight, more preferably at least 98% by weight, more preferably at least 99% by weight, more preferably at least 99.5% by weight, more preferably at least 99.9% by weight of the one or more solvents is Cyrene, and more preferably, the one solvent is Cyrene; or wherein the one or more solvents at least contain cyclohexanone, based on the total weight of the one or more solvents as 100% by weight, preferably at least 90% by weight of the one or more solvents, more preferably at least 95% by weight, more preferably at least 98% by weight, more preferably at least 99% by weight, more preferably at least 99.5% by weight, more preferably at least 99.9% by weight of the one or more solvents is cyclohexanone, and more preferably, the one solvent is cyclohexanone. 36. The method of any one of embodiments 1 to 35, wherein ethyl benzoate and butyl benzoate are not included as one or more solvents. 37. The method of any one of embodiments 1 to 36, wherein the solvent system comprises GVL, wherein based on the total weight of the solvent system as 100 wt%, preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 98 wt%, more preferably in the range of 99 to 100 wt% of the solvent system consists of GVL. 38. The method of any one of embodiments 1 to 37, wherein the depolymerization of (c) is carried out by a method selected from the group consisting of alcoholysis, glycolysis, hydrolysis, aminolysis, aminolysis and a mixture of two or more of these methods. 39. The method of Example 38, wherein the depolymerization of (c) is carried out by alcoholysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with a _C1 to _C4 alkyl monoalcohol, thereby obtaining di(C1 to _C4 alkyl) terephthalate and/or di(C1 to _C4 alkyl) isophthalate and ethylene glycol and/or cyclohexanedimethanol. 40. The method of Example 39, wherein the _C1 to _C4 alkyl monoalcohol is methanol, wherein dimethyl terephthalate and/or dimethyl isophthalate and ethylene glycol and/or cyclohexanedimethanol are obtained. 41. A method as in Example 37, wherein the depolymerization of (c) is carried out by glycolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with a _C1 to _{C6 alkyl} diol to obtain bis(hydroxy _C1 to C6 alkyl) terephthalate and/or bis(hydroxy _C1 to _C6 alkyl) isophthalate and ethylene glycol and/or cyclohexanedimethanol. 42. The method of Example 41, wherein the _C1 to _C6 alkyl diol is ethylene glycol, wherein bis(hydroxyethylene)terephthalate and/or bis(hydroxyethylene)isophthalate and/or bis( _hydroxyC1 to _C6 alkyl)isophthalate and ethylene glycol and/or cyclohexanedimethanol are obtained. 43. The method of Example 37, wherein the depolymerization of (c) is carried out by hydrolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with water, thereby obtaining terephthalic acid (TPA) and/or isophthalic acid and ethylene glycol and/or cyclohexanedimethanol. 44. The method of Example 43, wherein the depolymerization of (c) is carried out by alkaline hydrolysis. 45. The method of embodiment 43, wherein the hydrolysis is carried out by enzyme-catalyzed hydrolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with water in the presence of an enzyme, thereby obtaining terephthalic acid (TPA) and/or isophthalic acid and ethylene glycol and/or cyclohexanedimethanol. 46. The method of any one of embodiments 43 to 45, wherein the depolymerization of (c) is carried out by hydrolysis at a pressure in the range of 40 to 120 hPa. 47. The method of embodiment 37, wherein the depolymerization of (c) is performed by hydrolysis, wherein (c) comprises: (c.1) preparing a melt of the colorant-reduced polymeric material, thereby obtaining a melt of the colorant-reduced polymeric material; (c.2) contacting the melt of the polymeric material obtained in (c.1) with an alkali, preferably an inorganic alkali based on an alkali metal, more preferably sodium hydroxide, potassium hydroxide or a mixture of sodium hydroxide and potassium hydroxide, thereby obtaining an alkaline melt; (c.3) The alkaline melt obtained in (c.2) is brought into contact with water, thereby obtaining terephthalate (having corresponding alkali metal cations) and/or isophthalate (having corresponding alkali metal cations) and ethylene glycol and/or cyclohexanedimethanol. 48. The method of embodiment 37, wherein the depolymerization of (c) is carried out by aminolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with a monoalkylamine ^R1R2NH2 , wherein ^R1 is _{a C1} to _C4 ^alkyl group, and ^R2 is selected from a hydrogen atom and a _C1 to _C4 alkyl group; thereby obtaining ^R1R2NC (=O)-phenyl-C(=O ^{) NR2R1} , wherein the substituent at the phenyl ring is in the para-position or meta-position, and ethylene ^glycol and/or cyclohexanedimethanol. 49. The method of Example 37, wherein the depolymerization of (c) is carried out by aminolysis, wherein (c) comprises contacting the colorant-reduced polymerized material obtained in (b) with ammonia (NH ₃ ) to obtain H ₂ NC(═O)-phenyl-C(═O)NH ₂ , wherein the substituent at the phenyl ring is in the para- or meta-position, and ethylene glycol and/or cyclohexanedimethanol; wherein the ammonia is provided in a solvent-free form or dissolved in a solvent, wherein the solvent is preferably one or more of glycerol, a diol (preferably a C ₁ to C ₆ alkyl diol), an alcohol (preferably a C ₁ to C ₄ alkyl monoalcohol). 50. The method of Example 1, wherein the transesterification of (c) is carried out by an acid or base catalyzed reaction with an alcohol. 51. The method of embodiment 50, wherein one or more catalysts containing metal cations are used, wherein the metal is preferably titanium or tin. 52. The method of embodiment 50 or 51, wherein the alcohol is ^R3 -OH, wherein ^R3 is a linear or branched _C2 to _C12 alkyl residue. 53. The method of embodiment 52, wherein the alcohol is selected from the group consisting of 2-ethylhexanol, isopropanol, isononanol, pentanol, butanol, isomers of these alcohols, and mixtures of two or more thereof. 54. The method of any one of embodiments 1 to 53, wherein the polyalkylene terephthalate-based polymer is composed of oxyethylene units or oxybutylene units and oxyterephthalyl units, wherein in the case of oxyethylene units, the oxyterephthalyl units are replaced by oxyisophthalyl units in the range of 0 to 5 mol %, and/or the oxyethylene units are replaced by oxymethylenecyclohexenemethylene units in the range of 0 to 49 mol %; wherein more preferably, the polyalkylene terephthalate-based polymer is selected from the group consisting of polyethylene terephthalate (PET), poly(ethylene terephthalate-co-ethylene isophthalate) 55. The method of any one of Examples 1 to 54, wherein the third polymer (iv) is an elastic fiber, wherein the elastic fiber comprises, preferably consists of, one or more polyurethane-based elastic fibers and/or one or more polyester-based elastic fibers, and preferably, the elastic fiber comprises, preferably consists of, one or more polyurethane-based elastic fibers, and preferably, at least 40% of each of the above-mentioned polymers, based on 100% by weight of the total weight of the elastic fiber. 56. The method of any one of embodiments 1 to 55, wherein the coloring agent is selected from the group consisting of a dye and an optical brightener and a mixture of a dye and an optical brightener. 57. A method as described in any one of Examples 1 to 56, wherein the obtained polymer material with reduced colorant means that the L*a*b* value of the polymer material with reduced colorant changes as compared to the polymer material provided in (a) as follows: the absolute value of a* decreases, preferably by at least 0.2; and/or, preferably, the absolute value of b* changes, preferably by at least 0.2; and/or, preferably, the L* value increases, preferably by at least 4, each compared with the L*a*b* value of the colored polymer material provided in (a), wherein the L*a*b* value is determined according to DIN 5033 and DIN EN ISO 11664-1.6. 58. The method of any one of Examples 1 to 57, if the second polymer (iii) is present in the polymer material provided in (a), the method further comprises: (d) separating the second polymer (iii) from the monomers and/or oligomers or transesterification products obtained in (c), thereby obtaining separate monomers and/or oligomers or transesterification products and separate second polymer (iii). 59. The method of any one of Examples 17 to 58, comprising: (bx) washing the polymer material removed in (b.6) or separated in (b.2') with a washing solvent as appropriate, thereby obtaining a washed polymer material with reduced coloring agent compared to the polymer material provided in (a). 60. The method of any one of embodiments 14 or 17 to 59, comprising: (by) drying the polymeric material removed in (b.6) or separated in (b.2') and/or the washed polymeric material obtained in (bx). 61. The method of any one of embodiments 1 to 60, if a third polymer (iv) is present in the polymeric material provided in (a), the method further comprises: (bz) separating the third polymer (iv) from the colorant-rich solvent system obtained in (b), (b.4), (b.4.2.), (b.5) and/or (b.2'), thereby obtaining a separate third polymer (iv). 62. A monomer, oligomer or transesterification product of a polyalkylene terephthalate-based polymer obtained or obtainable by the method of any one of Examples 1 to 61, preferably step (d). 63. Preferably the method of any one of Examples 1 to 61, comprising the further step of: - converting, preferably polymerizing, the monomer, oligomer or transesterification product of a polyalkylene terephthalate-based polymer obtained or obtainable by the method of any one of Examples 1 to 61 to obtain one or more polymers or polymer products. 64. The method of embodiment 63, wherein the one or more polymers are polyalkylene terephthalate-based polymers, the polyalkylene terephthalate-based polymers are composed of oxyethylene units or oxybutylene units and oxyterephthalyl units, wherein in the case of oxyethylene units, the oxyterephthalyl units are replaced by oxyisophthalyl units in the range of 0 to 5 mol %, and/or the oxyethylene units are replaced by oxymethylenecyclohexenemethylene units in the range of 0 to 49 mol %; wherein more preferably, the polyalkylene terephthalate-based polymer is selected from the group consisting of polyethylene terephthalate (PET), poly(ethylene terephthalate-co-ethylene isophthalate) (PETI), polybutylene terephthalate (PBT) and a mixture of two or three of these polymers; wherein more preferably, the polyalkylene terephthalate-based polymer comprises or is PET. 65. The method of embodiment 63 or 64, wherein the polymer product is a textile, fiber, packaging, plastic, preferably: - A part of a car; preferably a cylinder head cover, an engine cover, a casing for a supercharged air cooler, a supercharged air cooler baffle, an intake pipe, an intake manifold, a connector, a large gear, a fan wheel, a cooling water tank, a casing, a casing part of a heat exchanger, a coolant cooler, a supercharged air cooler, a thermostat, a water pump, a radiator, a fastening part, a battery system part of an electric car, Instrument panels, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper guards, decorative grilles, cover strips, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, bumpers or coatings; - Cloth; preferably shirts, trousers, pullovers, boots, shoes, soles, leggings or jackets; - Electrical parts; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foils, wires, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, bobbins, lamps, diodes, LEDs, transistors, connectors, regulators, integrated circuits (ICs), processors, controllers, memories, sensors, micro switches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, spacers, screws, strips, slide-in guides, screws, nuts, film hinges, spring hooks (snap-on) or spring tongues for electrical or electronic components; - Consumer products, agricultural products or pharmaceutical products; preferably tennis string, climbing rope, bristles, brushes, artificial grass, 3D printing filaments, grass trimmers, zippers, hook and loop fasteners, paper machine fabrics, extruded coatings, fishing lines, fishing nets, marine lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyor belts, sliding bearings , rollers, wheels, gears, rollers, ring gears, screws and spring dampers, hoses, pipes, cable jackets, sockets, switches, cable ties, fan wheels, carpets, cosmetic cases or bottles, mattresses, cushions, insulating materials, cleaners, dishwashing tablets or powders, shampoos, body washes, shower gels, soaps, fertilizers, fungicides or insecticides; - packaging for the food industry; preferably single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxially stretched film or laminated film; or - part of a structure; preferably a rotor blade, insulation material, frame, shell, wall, coating or separator wall. 66. Preferably, the method according to any one of embodiments 1 to 61 comprises the further step of: - converting the separated second polymer (iii) and/or the separated third polymer (iv) obtainable by or by the method according to any one of embodiments 1 to 64, preferably the separated second polymer (iii) obtained or obtainable from step (d) and/or the separated third polymer (iv) obtained or obtainable from any one of steps (b), (b.4), (b.4.2.), (b.5) and (b.2'), to obtain one or more monomers, polymers or polymer products. 67. The method of Example 66, wherein the polymer is the following and/or the polymer product comprises the following: polyamide (PA); preferably PA 6 or PA 66; polyisocyanate addition polymer; preferably polyurethane (PU), thermoplastic polyurethane (TPU), polyurea or polyisocyanurate (PIR); low density polyethylene (LDPE), high density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrene (PS), polyacrylonitrile butadiene styrene (ABS), polystyrene acrylonitrile (SAN), polyacrylate styrene acrylonitrile (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate terephthalate (PBAT), polyester (PES), polyether sulphate (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulphide (PSU), polyphenylene sulphide (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene oxide) (PPO), poly(p-phenylene ether) (PPE); or its copolymer or mixture. 68. The method of embodiment 66 or 67, wherein the polymer and/or the polymer product is or is a part of: - a part of a car; preferably a cylinder head cover, an engine cover, a casing for a supercharged air cooler, a supercharged air cooler baffle, an intake pipe, an intake manifold, a connector, a gear, a fan wheel, a cooling water tank, a casing, a casing part of a heat exchanger, a coolant cooler, a supercharged air cooler, a thermostat, a water pump, a radiator, a fastening part, a battery system part of an electric car, Instrument panels, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper guards, decorative grilles, cover strips, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, bumpers or coatings; - Cloth; preferably shirts, trousers, pullovers, boots, shoes, soles, leggings or jackets; - Electrical parts; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foils, wires, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, bobbins, lamps, diodes, LEDs, transistors, connectors, regulators, integrated circuits (ICs), processors, controllers, memories, sensors, micro switches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, spacers, screws, strips, slide-in guides, screws, nuts, film hinges, spring hooks (snap-on) or spring tongues for electrical or electronic components; - Consumer products, agricultural products or pharmaceutical products; preferably tennis string, climbing rope, bristles, brushes, artificial grass, 3D printing filaments, grass trimmers, zippers, hook and loop fasteners, paper machine fabrics, extruded coatings, fishing lines, fishing nets, marine lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyor belts, sliding bearings , rollers, wheels, gears, rollers, ring gears, screws and spring dampers, hoses, pipes, cable jackets, sockets, switches, cable ties, fan wheels, carpets, cosmetic cases or bottles, mattresses, cushions, insulating materials, cleaners, dishwashing tablets or powders, shampoos, body washes, shower gels, soaps, fertilizers, fungicides or insecticides; - packaging for the food industry; preferably single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxially stretched film or laminated film; or - a part of a structure; preferably a rotor blade, insulating material, frame, shell, wall, coating or separating wall. 69. The method of embodiment 66 or 67, wherein the content of the separated second polymer (iii) and/or the separated third polymer (iv) in the polymer and/or the polymer product is 1 wt % or more, preferably 2 wt % or more, more preferably 5 wt % or more, more preferably 15 wt % or more, more preferably 30 wt % or more, more preferably 40 wt % or more, more preferably 60 wt % or more, more preferably 80 wt % or more, more preferably 90 wt % or more, more preferably 95 wt % or more; and/or wherein the polymer and/or the polymer product or the content of the separated second polymer in the polymer product is 100 wt % or less, preferably 95 wt % or less, more preferably 90 wt % or less, more preferably 50 wt % or less, more preferably 25 wt % or less, more preferably 10 wt % or less; and preferably, wherein the content is determined based on property preservation and/or isolation and/or mass balance and/or book and patent application scope supervision chain model, preferably based on mass balance, preferably International Sustainability and Carbon Certification (ISCC) standards.

The present invention is further described by the following reference examples, comparative examples and examples.

Examples Methods used for analysis : Gel Permeation Chromatography ( GPC ) : Sample preparation: 7.5 mg of sample was dissolved in 5 ml of solvent (hexafluoroisopropanol + 0.05 wt% potassium trifluoroacetate) overnight. All sample solutions were filtered through Millipore Millex FG (0.2 µm) before injection. The sealed sample vial was placed in the autosampler.

Experimental conditions: An Agilent 1100 HPLC system consisting of an isocratic pump, vacuum degasser, autosampler and column oven (40°C) was used. In addition, the Agilent system contained a differential refractive index (DRI) and variable ultraviolet (UVW) detector as detectors. Data acquisition and data processing of the known SEC data were performed by WinGPC Unichrom of PSS (Polymer Standard Services). A combination of Agilent's PL-HFIP guard column (7.5×50 mm) and 2 PL-HFIP gel columns (7.5×300 mm, 9 µ) were placed in series. As solubilizer, hexafluoroisopropanol + 0.05 wt% potassium trifluoroacetate was used for the originally supplied material and + 0.1 wt% potassium trifluoroacetate for the treated samples, with a flow rate of 1 ml/min for each sample. 50 µl of each sample solution was injected. Calibration was obtained with PMMA standards (Polymer Standard Services) with a narrow molar mass distribution, ranging from M = 800 to M = 2.200.000 g/mol for the originally supplied material and from M = 596 to M = 2.050.00 g/mol for the treated samples. Molar masses outside this range were extrapolated.

CIE-LAB : L*a*b* values are determined by measuring the sample with an integrating sphere and obtaining a UV/VIS light-mitigated spectrum (wavelength region 400-700 nm). The data of these spectra are analyzed by the software OptLab-SPX using a 2° standard observer and standard light type C. OptLab-SPX software calculates L*a*b* values according to DIN 5033 and DIN EN ISO 11664-1.6 from 2007 to 2014.

GC Area % : The sample is analyzed by gas chromatography (GC) where the method detects individual components in the sample based on their individual retention times. The concentration of the individual component in the sample is given as a percentage of its peak area, as GC Area %.

Chemical substances (Chemistry) name Abbreviation Polymer materials Polyethylene terephthalate PET Block copolymers containing polyurethane and polyethylene glycol or pTHF (≥85% by weight polyurethane) Elastic fiber (elastic man-made fiber) Solvent 2-Ethylhexanol -- Ethylene glycol -- water -- Acetone -- γ-Valerolactone GVL Sodium bicarbonate NaHCO ₃

Reference Example 1 : General procedure for single-use solvent system / coloring agent removal via gas flow 10 g of colored and optionally elastic fiber-containing polymer material (in any processed form, such as shredded/sheared textiles, sheets, etc.) are placed in a basket with holes, which is placed on a reaction vessel (such as a flask), especially above its opening, to which a solvent system is added (the ratio of solvent: polymer material based on mass is 100:1 to 1:1, preferably 80:1 to 10:1), wherein the basket and especially the material contained therein are not in direct contact with the solvent system, but gas and liquid communication can be established between the basket and the solvent system in the reaction vessel. The solvent system is heated in a reaction vessel using a suitable heating system (e.g., oil bath, heating block, microfab vessel) (i) under an inert gas atmosphere to a temperature at least equal to or above the boiling point of the solvent system, or (ii) to a temperature from 120°C to at most 30°C below the boiling point of the solvent. K and in contact with an inert gas at a flow rate of, for example, 24 liters/hour, so that a gas phase containing the solvent system is formed and the gas phase is brought into contact with the colored polymeric material in the basket, combined with the solvent system on the surface of the cooler and/or subsequently condensed (also including separation of the solvent contained in the gas phase in liquid form), wherein the condensed solvent system containing part of the coloring agent flows back into the reaction vessel containing the solvent system. Due to the continuous inert gas flow ( _N2 ) and the vapor/condensate of the solvent system formed, the colored polymeric material in the basket, optionally containing elastic fibers, is decolorized and the elastic fibers are removed as appropriate. After 0.1-8 hours, the system is cooled and the decolorized and, if applicable, elastic fiber-reduced polymeric material can be collected, thereby obtaining a solvent system rich in coloring agent and, if applicable, elastic fibers in a separate reaction vessel. In order to easily remove the solvent system and accelerate the drying process of the decolorized and, if applicable, elastic fiber-reduced polymeric material flakes, a small amount of acetone can be used in the optional washing step. The decolorized and, if applicable, elastic fiber-reduced polymeric material flakes thus obtained are dried (for example in a vacuum compartment dryer).

The samples were analyzed before the initial decolorization step (colored and, if applicable, elastomeric fiber-containing polymeric material) and after the final drying step (recycling and recovery of the colorless and, if applicable, elastomeric fiber-reduced PET solid). In case of color removal, the L*a*b* values were determined.

Examples 1 to 5 : Decolorization of PET by treatment with a gas and recondensing solvent system The polymeric material was treated according to the procedure of Reference Example 1, option (ii), and the results are listed in the following Table 1: Table 1 Summary materials and results of Examples 1 to 5 according to the procedure of Reference Example 1, option (ii). Instance Number Solvent system Polymer Materials color L*a*b* value Before treatment After fading 1 GVL PET Textiles Yellow L* = 78.2 a* = -10.8 b* = 42.3 L* = 86 a* = -1 b* = 6 2 GVL PET Textiles Green L* = 54.8 a* = -32.3 b* = 21.2 L* = 86 a* = -1 b* = 6 3 GVL PET Textiles blue L* = 36.9 a* = 1.0 b* = -6.0 L* = 85 a* = 0 b* = 5 4 GVL PET Textiles black L* = 35.8 a* = 0.1 b* = -0.8 L* = 81 a* = 1 b* = 7 5 GVL PET Textiles Black (different sources) L* = 36.9 a* = -0.8 b* = -2.3 L* = 88 a* = 0 b* = 2

For the green PET textile of Example 2 and the black PET textile of Example 5, the molecular weight (Mn, Mw) and dispersion degree before and after treatment were determined based on GPC. The results are shown in Table 2 below. Table 2 Molecular weight and dispersion degree of green and black textiles before and after treatment (GPC) Before treatment After treatment Example 2 : Green Textiles Number average molecular weight Mn [g/mol] 16900 25800 Mass average molecular weight Mw [g/mol] 45100 49500 Dispersion Mw/Mn 2.7 1.9 Example 5 : Black Textile Number average molecular weight Mn [g/mol] 16800 29400 Mass average molecular weight Mw [g/mol] 48500 55700 Dispersion Mw/Mn 2.9 1.9

It was found that the use of a solvent system in the form of a gas stream (here GVL was used as solvent system) in combination with recondensation and/or separation in liquid form allows the removal of coloring agents from polymeric materials (here PET textiles of different colors) to be effective without at least damaging the number average molecular weight Mn of the recovered PET (Mn of the recovered PET) which is always greater than or at least equal to the Mn of the PET contained in the material initially provided. The same even applies to the mass average molecular weight Mw, which is also always greater or at least equal after the treatment. The dispersity Mw/Mn (mass average molecular weight Mw divided by the number average molecular weight Mn) of the recovered PET is in the range of 60 to 95%, preferably in the range of 75 to 90%, of the dispersity Mw/Mn of the PET contained in the material provided (100%).

Example 6 : Transesterification of PET to DOTP A reactor equipped with a distillation column was filled with 2-ethylhexanol (8.0 equivalents, based on weight), the color-reduced PET from Example 2 (1.0 equivalents, based on weight), and NaHCO ₃ (1.25 wt %, compared to 100 wt % PET). The stirred mixture was heated to up to 220° C. while continuously distilling off a mixture of 2-ethylhexanol and ethylene glycol. An equivalent amount of fresh 2-ethylhexanol compared to the distilled 2-ethylhexanol was added to the reaction mixture. Distillation was continued until the distillate no longer contained any ethylene glycol, which was determined by density measurement. Excess 2-ethylhexanol is distilled off and the crude product dioctyl terephthalate DOTP, bis(2-ethylhexyl) terephthalate is separated by filtration (e.g., heated pressure filtration at 120°C), optionally with a filter aid. Purity of DOTP (GC area %): 99.85%

Reference Example 2 : Removal of coloring agent from solution PET textile (of any color) is cut/torn into pieces and placed in a reaction vessel (e.g., flask, tube, reaction vessel). A solvent system is added (solvent: polymer material ratio based on mass is 100:1 to 1:1, preferably 10:1 to 1:1), and the mixture is heated to a temperature in the range of 60 to 160° C. by using a suitable heating system (e.g., oil bath, heating block, micro-factory container). After 0.5-8 hours, the mixture is filtered, thereby obtaining a solvent enriched in coloring agent and decolorized polymer material, and the color-reduced polymer material is washed with a small amount of the respective solvent. In order to facilitate the removal of the solvent and to speed up the drying process of the depigmented polymeric material sheet, a small amount of acetone may be used in the second washing step. The depigmented polymeric material thus obtained is dried (for example in a vacuum chamber dryer).

Example 7 : Decolorization of PET by treatment with a solvent system in solution According to the procedure of Reference Example 2, 10 g of black PET textile was treated with GVL as solvent at 150°C for 4 hours. The L*a*b* values before and after treatment were determined. The results are listed in Table 3 below: Table 3 Summary of Example 7 Materials and Results - L*a*b* Values Instance Number Solvent system Polymer Materials color L*a*b* value Before treatment After treatment (decolorization) 7 GVL PET Textiles black L* = 36.9 a* = -0.7 b* = -2.3 L* = 88 a* = 0.9 b* = 2.2

Example 8 : Depolymerization A mixture of 0.5 g of previously decolorized PET textile flakes from Example 7, 4.25 g of ethanol, 0.75 g of deionized water and 0.23 g of sodium hydroxide was filled into a glass container with a magnetic stirrer and heated to 160° C. by microwave irradiation for 1 hour. The white suspension was cooled to ambient temperature, filtered and washed with ethanol (2×2 ml). The white solid obtained was redissolved in 10 g of hot water and filtered to give a colorless clear solution. In addition, the filtrate was treated with 0.5 g of concentrated sulfuric acid, resulting in a white fine powder precipitate. The obtained solid was removed by filtration and dried in vacuum at 80° C. overnight to afford terephthalic acid (0.36 g, yield 96%) as a white solid. The ¹ H NMR spectrum of the product was measured and showed no impurities ( FIG. 1 ).

Comparative Example 1 : Decolorization according to the prior art US 2016/0009893 A1 describes the removal of color with ethylene glycol (EG). 10 g of black PET textile are cut/shredded into pieces and placed in a reaction vessel (e.g., a flask, a tube, a reaction vessel). 100 mL of ethylene glycol are added, and the mixture is heated to a temperature of 150° C. by using a suitable heating system (e.g., an oil bath, a heating block, a microfactory container). After 4 hours, the mixture is filtered and the polymeric material is washed with a small amount of ethylene glycol. In order to easily remove the ethylene glycol and speed up the drying process of the polymeric material pieces, a small amount of acetone can be used in the second washing step. The polymeric material thus obtained is dried (e.g., in a vacuum compartment dryer). The L*a*b* values before and after treatment were measured, and the molecular weight and dispersity before and after treatment were measured by GPC. The results are listed in Tables 4 and 6 below: Table 4 Summary of Comparative Example 1 Materials and Results - L*a*b* Values Instance Number Solvent system Polymer Materials color L*a*b* value Before treatment After treatment (not faded) 7 GVL PET Textiles black L* = 36.9 a* = -0.7 b* = -2.3 L* = 54 a* = 0 b* = 1 Table 5 Summary of Materials and Results of Comparative Example 1 - GPC Instance Number Solvent system Polymer Materials color Number average molecular weight Mn [g/mol] Mass average molecular weight Mw [g/mol] Dispersion Mw/Mn 7 GVL PET Textiles black forward back forward back forward back 17300 15700 48600 38200 2.8 2.4

It was found that ethylene glycol was not able to decolorize PET, as is evident from the L*a*b* values of Example 7 (Table 2) compared to the L*a*b* values of Example 1 (Table 4). In addition, attempts to use ethylene glycol as a decolorizing solvent resulted in a significant decrease in the average molecular weight of PET.

Examples 9 to 12 : Decolorization of PET by treatment with a gas and recondensing solvent system The polymeric material was treated according to the procedure of option (i) of reference example 1 and the results are listed in the following Table 6: Table 6 Summary materials and results of Examples 9, 10, 11 and 12 according to the general procedure of option (i) of reference example 1. Instance Number Polymer Materials Solvent system color L*a*b* value Before treatment After fading 9 PET Textiles GVL black L* = 36.9 a* = -0.8 b* = -2.3 L* = 84 a* = 0 b* = 2 10 PET Textiles Cyrene black L* = 36.9 a* = -0.8 b* = -2.3 L* = 89 a* = -1 b* = 2 11 PET Textiles DMSO black L* = 36.9 a* = -0.8 b* = -2.3 L* = 87 a* = -1 b* = 1 12 PET Textiles Cyclohexanone black L* = 36.9 a* = -0.8 b* = -2.3 L* = 87 a* = 0 b* = 4

It was found that the use of a solvent system in the form of a gas stream combined with recondensation and/or separation in the form of a liquid can effectively remove coloring agents from polymeric materials (here PET textiles of different colors).

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FIG1 shows the ¹ H NMR spectrum of terephthalic acid obtained from the depolymerization of Example 8 in DMSO- d ₆ (*).

Claims (13)

A method for recycling a colored polymeric material, wherein the colored polymeric material comprises (i) a polyalkylene terephthalate-based polymer; (ii) a colorant; and optionally (iii) a second polymer different from the polyalkylene terephthalate-based polymer of (i); and optionally (iv) a third polymer different from the polyalkylene terephthalate-based polymer of (i) and different from the second polymer of (iii), the method comprising: (a) providing a colored polymeric material and a solvent system comprising gamma valerolactone (GVL); (b) Contacting the colored polymeric material provided in (a) with the solvent system comprising GVL provided in (a) under conditions that allow removal of the colorant but do not allow dissolution of the polyalkylene terephthalate-based polymer, thereby obtaining a solvent system enriched in colorant compared to the solvent system provided, and a polymeric material reduced in colorant compared to the colored polymeric material provided in (a); (c)  depolymerizing or transesterifying the polymeric material reduced in colorant obtained in (b); thereby obtaining monomers and/or oligomers or transesterification products. The method of claim 1, wherein (b) comprises: (b.1) providing the colored polymer material in a first container and providing the solvent system in a second container; wherein the first container and the second container are spatially separated from each other but allow gas and fluid communication between each other; (b.2) forming a gas stream containing at least a portion of the solvent system and removing the gas stream from the second container; (b.3) separating the solvent system in liquid form from the gas stream at a position outside the second container (also outside the first container) to obtain a solvent system in liquid form; (b.4) contacting the colored polymer material in the first container with the solvent system in liquid form, the solvent system having been separated from the gas stream in (b.3), Thereby, a solvent system rich in colorant and optionally third polymer (iv) compared to the solvent system provided in (a) is obtained, as well as a polymeric material which is reduced in colorant and optionally third polymer (iv) compared to the colored polymeric material provided in (a) and comprises the polyalkylene terephthalate-based polymer (i) and optionally a second polymer (iii). The method of claim 1, wherein (b) comprises: (b.1') contacting the colored polymer material of (a) with a solvent system at a temperature T of <170°C, thereby obtaining a solvent system rich in colorant and optionally rich in a third polymer (iv) compared to the solvent system provided in (a), and a polymer material having reduced colorant and optionally reduced third polymer (iv) compared to the colored polymer material provided in (a); (b.2') optionally separating the polymer material from the solvent system, wherein the colorant and optionally the third polymer (iv) are reduced and the polymer material comprises the polyalkylene terephthalate-based polymer. A method as claimed in any one of claims 1 to 3, wherein, based on the total weight of the solvent system as 100 weight %, at least 90 weight %, more preferably at least 95 weight %, more preferably at least 98 weight %, and more preferably in the range of 99 to 100 weight % of the solvent system consists of GVL. The method of any one of claims 1 to 4, wherein the depolymerization of (c) is carried out by a method selected from the group consisting of alcoholysis, glycolysis, hydrolysis, aminolysis, aminolysis and a mixture of two or more of these methods. The method of any one of claims 1 to 4, wherein the transesterification of (c) is carried out by an acid- or base-catalyzed reaction with an alcohol. The method of any one of claims 1 to 6, wherein the second polymer (iii) is selected from the group consisting of: polypropylene (PP); polyethylene (PE); polyamide (PA), preferably PA6 and/or PA66; natural polymers, preferably cotton, viscose, linen and mixtures of two or more thereof; and/or wherein the third polymer (iv) is an elastic fiber, the elastic fiber preferably comprises, preferably consists of, one or more polyurethane-based elastic fibers and/or one or more polyester-based elastic fibers, more preferably, the elastic fiber comprises one or more polyamine-based elastic fibers. Preferably, the elastic fiber is composed of an elastic fiber based on polyurethane, wherein, based on the total weight of the elastic fiber as 100 weight%, preferably at least 40 weight%, preferably at least 45 weight%, preferably at least 50 weight%, preferably at least 55 weight%, preferably at least 60 weight%, preferably at least 65 weight%, preferably at least 70 weight%, preferably at least 75 weight%, preferably at least 80 weight%, preferably at least 85 weight%, preferably at least 90 weight%, preferably at least 95 weight%, preferably at least 99.9 weight% of the elastic fiber is one or more polyurethane-based elastic fibers. The method of any one of claims 1 to 7, wherein the coloring agent is selected from the group consisting of a dye and an optical brightener and a mixture of a dye and an optical brightener. A method as in any one of claims 1 to 8, wherein the polyalkylene terephthalate-based polymer comprises or is PET. A monomer, oligomer or transesterification product of a polyalkylene terephthalate-based polymer, which is obtained or obtainable by the method of any one of claims 1 to 9. A method as claimed in any one of claims 1 to 9, comprising the further step of: Converting, preferably polymerizing, a monomer, oligomer or transesterification product of a polyalkylene terephthalate-based polymer obtainable according to or obtainable according to any one of claims 1 to 10 to obtain one or more polymers or polymer products; wherein the one or more polymers are preferably polyalkylene terephthalate-based polymers; and wherein the polymer product is a textile, fiber, packaging, plastic, more preferably: A part of a car; preferably a cylinder head cover, an engine cover, a casing for a supercharged air cooler, a supercharged air cooler baffle, an intake pipe, an intake manifold, a connector, a large gear, a fan wheel, a cooling water tank, a casing, a casing part of a heat exchanger, a coolant cooler, a supercharged air cooler, a thermostat, a water pump, a radiator, a fastening part, a battery system part of an electric car, an instrument Dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper guards, decorative grilles, cover strips, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, bumpers or coatings; Cloth; preferably shirts, trousers, pullovers, boots, shoes, soles, leggings or jackets; Electrical parts; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foils, wires, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, bobbins, lamps, diodes, LEDs, transistors, connectors, regulators, integrated circuits (ICs), processors, controllers, memories, sensors, micro switches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, spacers, screws, strips, slide-in guides, screws, nuts, film hinges, spring hooks (snap-on) or spring tongues for electrical or electronic components; Consumer products, agricultural products or pharmaceutical products; preferably tennis string, climbing rope, bristles, brushes, artificial grass, 3D printing filaments, grass trimmers, zippers, hook and loop fasteners, paper machine fabrics, extruded coatings, fishing lines, fishing nets, marine lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyor belts, sliding bearings , rollers, wheels, gears, rollers, ring gears, screws and spring dampers, hoses, pipes, cable sheathing, sockets, switches, cable ties, fan wheels, carpets, cosmetic cases or bottles, mattresses, cushions, insulating materials, cleaners, dishwashing tablets or powders, shampoos, body washes, shower gels, soaps, fertilizers, fungicides or insecticides; Packaging for the food industry; preferably single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film or laminated film; or Part of a structure; preferably a rotor blade, insulating material, frame, shell, wall, coating or separator wall. A method as claimed in any one of claims 1 to 9, comprising the further step of: Converting the separated second polymer (iii) and/or the separated third polymer (iv) obtainable by or by the method as claimed in any one of claims 1 to 9 to obtain one or more monomers, polymers or polymer products. The method of claim 12, wherein the polymer is the following and/or the polymer product comprises the following: polyamide (PA); preferably PA 6 or PA 66; polyisocyanate addition polymer; preferably polyurethane (PU), thermoplastic polyurethane (TPU), polyurea or polyisocyanurate (PIR); low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrene (PS), polyacrylonitrile butadiene styrene (ABS), polystyrene acrylonitrile (SAN), polyacrylate styrene acrylonitrile (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate terephthalate (PBAT), polyester (PES), polyether sulphate (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulphide (PSU), polyphenylene sulphide (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene oxide) (PPO), poly(p-phenylene ether) (PPE); or its copolymer or mixture; and/or wherein the polymer and/or the polymer product is or is part of: a part of a car; preferably a cylinder head cover, an engine cover, a casing for a supercharged air cooler, a supercharged air cooler baffle, an intake pipe, an intake manifold, a connector, a gear, a fan wheel, a cooling water tank, a casing, a casing part of a heat exchanger, a coolant cooler, a supercharged air cooler, a thermostat, a water pump, a radiator, a fastening part, a battery system part of an electric car, an instrument Dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper guards, decorative grilles, cover strips, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, bumpers or coatings; Cloth; preferably shirts, trousers, pullovers, boots, shoes, soles, leggings or jackets; Electrical parts; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foils, wires, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, bobbins, lamps, diodes, LEDs, transistors, connectors, regulators, integrated circuits (ICs), processors, controllers, memories, sensors, micro switches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, spacers, screws, strips, slide-in guides, screws, nuts, film hinges, spring hooks (snap-on) or spring tongues for electrical or electronic components; Consumer products, agricultural products or pharmaceutical products; preferably tennis string, climbing rope, bristles, brushes, artificial grass, 3D printing filaments, grass trimmers, zippers, hook and loop fasteners, paper machine fabrics, extruded coatings, fishing lines, fishing nets, marine lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyor belts, sliding bearings , rollers, wheels, gears, rollers, ring gears, screws and spring dampers, hoses, pipes, cable sheathing, sockets, switches, cable ties, fan wheels, carpets, cosmetic cases or bottles, mattresses, cushions, insulating materials, cleaners, dishwashing tablets or powders, shampoos, body washes, shower gels, soaps, fertilizers, fungicides or insecticides; Packaging for the food industry; preferably single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film or laminated film; or Part of a structure; preferably a rotor blade, insulating material, frame, shell, wall, coating or separator wall.