Process for producing biogas from residues of polymer blends comprising cellulose-based polymers

Abstract

In a first aspect, the present invention relates to a process for preparing biogas, the process comprising providing a polymer blend comprising (i) a polyester and (ii) optionally one or more components selected from the group consisting of a second polymer, a colorant and a filler; (iii) a cellulose-based third polymer; wherein the optional second polymer (ii) and the cellulose-based third polymer (iii) are different from each other and from the polyester of (i); the process comprises: a step (e) involving the production of biogas from the residue of the polymer blend which is polyester-depleted and comprises the cellulose-based third polymer and optionally the filler or a portion of the filler obtained in the previous step (c).

Description

[0001] In a first aspect, the present invention relates to a method for preparing biogas, the method comprising providing a polymer blend comprising (i) a polyester and (ii) one or more components optionally selected from the group consisting of a second polymer, a colorant, and a filler; (iii) a cellulose-based third polymer; wherein the optional second polymer (ii) and the cellulose-based third polymer (iii) are different from each other and different from the polyester of (i); the method comprising: (a) providing the polymer blend and providing a solvent system comprising γ-valerol (GVL) or dimethyl sulfoxide (DMSO) or a mixture of GVL and DMSO, the solvent system comprising one or more acidic and / or basic components having a total weight of 100 wt% based on the solvent system, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%; (b) optionally reacting the polymer blend with the solvent system in < (a) Contacting the solvent system at a temperature T1 of 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof, and a residue of a polymer blend depleted of the second polymer and / or colorant and optionally filler or a portion thereof and comprising polyester, optionally a cellulose-based third polymer and optionally filler or a portion thereof; (b) Contacting the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) with the solvent system at a temperature T2 of >170°C to obtain a solvent system rich in dissolved polyester and optionally comprising filler or a portion thereof compared to the solvent system provided in (a), and a residue of a polymer blend depleted of polyester and comprising a cellulose-based third polymer and optionally filler or a portion thereof; (c) Optionally precipitating polyester from the solvent system rich in dissolved polyester obtained in (c) to obtain a solvent system with precipitated polyester and depleted dissolved polyester and optionally comprising filler or a portion thereof; (d) From (c) Biogas is prepared from the residue of a polymer blend containing a lean polyester and optionally a third cellulose-based polymer and a filler or a portion thereof; wherein the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) is not contacted with the acidic and / or alkaline components before (b), between (b) and (c), or before (c).A second aspect of the invention relates to a method for preparing biogas from a cellulose-based polymer separated from a polymer blend, the method comprising (i) separating the cellulose-based polymer from a polymer blend comprising the cellulose-based polymer and at least one other polymer different from the cellulose-based polymer, thereby obtaining a separated cellulose-based polymer fraction; (ii) treating the cellulose-based polymer fraction obtained in (i) with a solvent system comprising γ-valerate (GVL), thereby obtaining a treated cellulose-based polymer fraction, the solvent system comprising one or more acidic and / or basic components comprising, by weight, 100% less than 1 ... Neither the polymer blends nor the separated cellulose-based polymer fractions are allowed to come into contact with the acidic and / or alkaline components. In a third aspect, the invention relates to biogas, preferably methane-containing biogas, which is obtained or available by the method of the first or second aspect. A fourth aspect of the invention relates to the use of the biogas according to the third aspect as a carbon source and / or hydrogen source; and / or the use of the biogas according to the third aspect as an energy source, preferably a thermal energy source, for one or more of steps (b) to (d). A fifth aspect of the invention relates to a polyester obtained or available by the method of the first or second aspect. A sixth aspect of the invention relates to the use of the polyester of the fifth aspect for textile applications, fiber applications, packaging applications, plastic applications, automotive applications, and / or electronic applications. In a seventh aspect, the invention relates to a method for preparing a product, the method comprising (I) providing the polyester of the fifth aspect; and (II) preparing textiles, fibers, packaging, plastics, automotive parts, and electronic parts from the polyester provided in (I). An eighth aspect of the invention relates to a method focused on obtaining a separated fraction comprising a second polymer; and a ninth aspect of the invention relates to a method focused on converting a second polymer and / or a re-obtained polyester to obtain one or more monomers, polymers, or polymer products. Background Technology

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

[0003] Several attempts have been made to further utilize such natural polymers as cotton, or at least improve, for example, their digestibility: Anacleto et al. (2022) summarized a variety of pretreatment methods for improving the anaerobic digestion of textile waste and textile dyeing sludge, such as enzymatic, (thermo)chemical, biological, and physical pretreatment methods, as well as commonly used treatments such as those using NaOH and 4-methylmorpholine 4-oxide (NMMO) (Anacleto, TM; Kozlowsky-Suzuki, B.; Wilson, AE; Enrich-Prast, A. Comprehensive Meta-Analysis of Pathways to Increase Biogas Production in the Textile Industry. Energies 2022, 15, 5574. https: / / doi.org / 10.3390 / en15155574). Hasanzadeh et al. (2018) have applied Na₂CO₃ treatment to hydrolyze the polyester and cotton portions of blended textiles. They found that Na₂CO₃ treatment did indeed increase biogas production in subsequent anaerobic digestion (Elnaz Hasanzadeh, Safoora Mirmohamadsadeghi, Keikhosro Karimi, Enhancing energy production from waste textile by hydrolysis of synthetic parts, Fuel, Vol. 218, 2018, pp. 41-48, ISSN 0016-2361, https: / / doi.org / 10.1016 / j.fuel.2018.01.035). Kumar et al. (2020) demonstrated the co-digestion of aerobic textile sludge with cow dung and food waste in a laboratory-scale BMP test (0.5 L).Here, the aerobic sludge from textiles used for BMP testing was collected from wastewater treatment equipment in textile facilities and had already undergone microbial degradation during aerobic treatment (Kumar, P., Samuchiwal, S. & Malik, A. Anaerobic digestion of textile industries wastes for biogas production. Biomass Conv. Bioref. 10,715–724 (2020). https: / / doi.org / 10.1007 / s13399-020-00601-8). Xiang et al. (2016) tested different pretreatment methods for the anaerobic digestion of organic compounds in textile dyeing sludge during textile manufacturing. (Xinyi Xiang, Xiaoguang Chen, Ruobin Dai, Ying Luo, Puyue Ma, Shengsheng Ni, Chengyu Ma, Anaerobic digestion of recalcitrant textile dyeing sludge with alternative pretreatment strategies, Bioresource Technology, Vol. 222, 2016, pp. 252-260, ISSN 0960-8524, https: / / doi.org / 10.1016 / j.biortech.2016.09.098).

[0004] Among other drawbacks, most commonly used methods must rely on corrosive chemicals such as NaOH and / or solvents that are at least irritating, such as NMMO. Furthermore, microbial fermentation using mixed materials such as polymer blends has not yet been feasible. Therefore, further simplification of the separation of natural polymers such as cotton and / or improvement of their digestibility are still needed to increase biogas production, for example, in microbial fermentation, while avoiding or at least minimizing the use of toxic solvents.

[0005] Therefore, the technical problem on which this invention is based is to provide a method for separating natural cellulose-based polymers from polymer materials, which overcomes these disadvantages and is particularly capable of obtaining digestible cellulose-based polymers.

[0006] In a first aspect, the present invention relates to a method for producing biogas, the method comprising:

[0007] Provides a polymer blend comprising

[0008] (i) Polyester, and

[0009] (ii) Optionally, one or more components selected from the group consisting of a second polymer, a colorant, and a filler;

[0010] (iii) Cellulose-based third polymers;

[0011] The optional second polymer (ii) and the cellulose-based third polymer (iii) are different from each other and different from the polyester of (i);

[0012] The method includes:

[0013] (a) Provide polymer blends and solvent systems;

[0014] (b) Optionally, the polymer blend is contacted with a solvent system at a temperature T1 of < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof, and a residue of a polymer blend depleted in the second polymer and / or colorant and optionally filler or a portion thereof and comprising polyester, optionally cellulose-based third polymer and optionally filler or a portion thereof;

[0015] (c) Contact the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) with a solvent system at a temperature T2 > 170°C to obtain a solvent system rich in dissolved polyester and optionally containing filler or a portion of filler compared to the solvent system provided in (a), and a residue of a polymer blend that is lean in polyester and contains a cellulose-based third polymer and optionally a filler or a portion of filler;

[0016] (d) Optionally, precipitate polyester from the solvent system rich in dissolved polyester obtained in (c) to obtain a solvent system containing precipitated polyester and dissolved polyester and optionally a filler or a portion thereof.

[0017] (e) Prepare biogas from the residue of a polymer blend of a lean polyester obtained in (c) and a polymer blend containing a cellulose-based third polymer and optionally a filler or a portion thereof.

[0018] Surprisingly, the method of the present invention not only separates cellulose-based polymers from polymer blends that also contain polyesters, but also allows the separated residues containing cellulose-based polymers to be used for biogas production with efficiency comparable to other commonly used pretreatments.

[0019] In some embodiments, the method for producing biogas includes

[0020] Provides a polymer blend comprising

[0021] (i) Polyester, and

[0022] (ii) Optionally, one or more components selected from the group consisting of a second polymer, a colorant, and a filler;

[0023] (iii) Cellulose-based third polymers;

[0024] The optional second polymer (ii) and the cellulose-based third polymer (iii) are different from each other and different from the polyester of (i);

[0025] The method includes:

[0026] (a) Providing a polymer blend and providing a solvent system comprising γ-valerol (GVL) or dimethyl sulfoxide (DMSO) or a mixture of GVL and DMSO, the solvent system comprising one or more acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight.

[0027] (b) Optionally, the polymer blend is contacted with a solvent system at a temperature T1 of < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof, and a residue of a polymer blend depleted in the second polymer and / or colorant and optionally filler or a portion thereof and comprising polyester, optionally cellulose-based third polymer and optionally filler or a portion thereof;

[0028] (c) Contact the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) with a solvent system at a temperature T2 > 170°C to obtain a solvent system rich in dissolved polyester and optionally containing filler or a portion of filler compared to the solvent system provided in (a), and a residue of a polymer blend that is lean in polyester and contains a cellulose-based third polymer and optionally a filler or a portion of filler;

[0029] (d) Optionally, precipitate polyester from the solvent system rich in dissolved polyester obtained in (c) to obtain a solvent system containing precipitated polyester and dissolved polyester and optionally a filler or a portion thereof.

[0030] (e) Prepare biogas from the residue of a polymer blend of lean polyester obtained in (c) and comprising a cellulose-based third polymer and optionally a filler or a portion thereof;

[0031] Before (b), between (b) and (c), and before (c), the polymer blend provided in (a) or, optionally, the residue of the polymer blend obtained in (b) shall not come into contact with the acidic and / or basic components. Regarding the preliminary and / or intermediate steps, the expression "contact with acidic and / or basic components" means not contacting the corresponding material with a medium comprising one or more acidic and / or basic components in an amount of 100% by weight, ≥ 1% by weight, preferably ≥ 2% by weight, more preferably ≥ 4% by weight, more preferably ≥ 4% by weight, more preferably ≥ 5% by weight, more preferably ≥ 6% by weight, more preferably ≥ 8% by weight, more preferably ≥ 10% by weight.

[0032] The fact that no contact with the acidic and / or basic components is performed before (b), between (b) and (c), and before (c) provides the advantage that a method with fewer steps is achieved, which makes the method economically advantageous.

[0033] Preferably, the residue of the lean polyester obtained in (c) and the polymer blend comprising a cellulose-based third polymer and optionally a filler or a portion thereof comprises one or more acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight. Preferably, the precipitated polyester obtained in (d) comprises one or more acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight.

[0034] Using a solvent system containing γ-valerol (GVL) that is substantially free of one or more acidic and / or basic components, and avoiding contact with acidic and / or basic components before (b) and between (b) and (c), and before (c), allows for obtaining in (c) a residue of a polymer blend that is lean polyester and contains a cellulose-based third polymer and optionally a filler or a portion thereof, which is substantially free of one or more acidic and / or basic components. This, in turn, allows for obtaining a residue of such a polymer blend having a pH in the range of 3.5 to 7, i.e., close to the pH required for optimal hydrolysis of cellulose materials by cellulose-decomposing bacteria and subsequent microbial decomposition to produce biomethane, bio-CO2, and bio-C2-C7 acids (preferably around 5.5 to 7). Therefore, this allows for the omission or at least reduction of the amount of washing solvent required. This makes the method more economical and environmentally friendly.

[0035] In optional step (b) and step (c), “contact” preferably means immersing at least partially the polymer blend provided in (a) or the residue of the polymer blend optionally obtained in (b) in the solvent system. Preferably, immersing at least partially the polymer blend provided in (a) or the residue of the polymer blend optionally obtained in (b) in the solvent system means that at least 60%, more preferably at least 70%, more preferably at least 80%, more preferably at least 90%, more preferably at least 95%, more preferably at least 99% of the surface of the polymer blend provided in (a) or the surface of the residue of the polymer blend optionally obtained in (b) is in contact with the solvent system. Regarding the optional step (b), "rich in the second polymer" means that based on 100% by weight of the second polymer (if present) contained in the material provided in (a), at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight are dissolved in the solvent system. Regarding the residue obtained (optionally) in (b), "depleted in the second polymer" means that based on 100% by weight of the second polymer (if present) contained in the material provided in (a), ≤ 50% by weight, preferably ≤ 40% by weight, more preferably ≤ 30% by weight, more preferably ≤ 20% by weight, more preferably ≤ 10% by weight, and more preferably ≤ 5% by weight are still present in the residue. Regarding the optional step (b), "rich in colorant" means that at least 50% by weight of the colorant (if present) contained in the polyester of the material provided in (a) is dissolved in the solvent system, based on 100% by weight of the colorant contained in the polyester of the material provided in (a). Preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the colorant (if present) contained in the polyester of the material provided in (a).Regarding the residue obtained in (b) (optionally), "depleted of the colorant" means that, based on 100% by weight of the colorant (if present) contained in the polyester of the material provided in (a), ≤ 50% by weight, preferably ≤ 40% by weight, more preferably ≤ 30% by weight, more preferably ≤ 20% by weight, more preferably ≤ 10% by weight, and more preferably ≤ 5% by weight of the colorant (if present) contained in the polyester of the material provided in (a) still remain in the residue. This means that the colorant contained in the polyester (i) is relatively easy to remove in step (b), i.e., dissolves in the solvent system together with the polyester in step (c), while the colorant contained in the third polymer (if present) is not easily dissolved, but is largely retained in the third polymer, and therefore also in the residue containing the third polymer. Regarding step (c), “a solvent system rich in dissolved polyester compared to the solvent system provided in (a)” means that based on 100% by weight of the polyester contained in the material provided in (a), at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, and more preferably at least 95% by weight of the polyester contained in the material provided in (a) is dissolved in the solvent system. Regarding the residue of the optionally obtained polymer blend in step (c), “depleted polyester and optionally containing a third polymer” means that based on 100% by weight of the polyester contained in the material provided in (a), ≤ 50% by weight, preferably ≤ 40% by weight, more preferably ≤ 30% by weight, more preferably ≤ 20% by weight, more preferably ≤ 10% by weight, more preferably ≤ 5% by weight of the polyester contained in the material provided in (a) still exists in the residue, wherein based on 100% by weight of the third polymer contained in the material provided in (a) (if present), at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight of the third polymer contained in the material provided in (a) (if present) still exists in the residue. Regarding the optional step (d), "solvent system of lean dissolved polyester" means that at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, and more preferably at least 90% by weight of the polyester contained in the solvent system obtained in (c) are precipitated and no longer dissolved in the solvent system.Regarding the solvent system obtained in step (b), the statement "optionally rich in filler or a portion of filler" and regarding the residue obtained in (b), the statement "optionally lean in filler or a portion of filler" means that if filler is present in the polymer blend provided in (a) (which is soluble in the solvent system at temperature T1), then the soluble filler is also dissolved in the solvent system obtained in (b), and therefore the residue is lean in the soluble filler. If the polymer blend provided in (a) contains not only filler soluble at T1, but also filler insoluble in the solvent system at temperature T1, the insoluble filler remains in the residue of the polymer blend obtained in (b). If the insoluble filler is then soluble in the solvent system at T2, then the insoluble filler is then dissolved in the solvent system at T2, and therefore the solvent system obtained in (c) is rich in the filler, and the residue obtained in (c) is lean in the filler. In the case where the polymer blend provided in (a) contains only one or more fillers that are soluble in the solvent system at temperature T1, no filler is retained in the residue of the polymer blend obtained in (b), and therefore the residue obtained in (c) also does not contain filler. In the case where the polymer blend provided in (a) contains only one or more fillers that are insoluble in the solvent system at temperature T2, all of the one or more fillers are retained in the residue of the polymer blend obtained in (b), but are therefore completely dissolved in the solvent system at T2, and therefore the residue obtained in (c) does not contain filler. In the case where the polymer blend provided in (a) contains one or more fillers that are insoluble in the solvent system at temperature T1 and one or more fillers that are insoluble in the solvent system at temperature T2, these insoluble fillers are retained in the residue obtained in (c).

[0036] Cellulose-based third polymer (iii)

[0037] In some embodiments of the method, the cellulose-based third polymer is selected from the group consisting of: polymers based on natural cellulose, polymers based on synthetic cellulose, and mixtures of one or more polymers based on natural cellulose and one or more polymers based on synthetic cellulose, wherein the polymer based on natural cellulose is preferably selected from the group consisting of: cotton, cellulose, lignin, linseed, viscose fiber, and mixtures of two or more thereof, and wherein the polymer based on synthetic cellulose is preferably viscose fiber, wherein the polymer based on cellulose preferably contains at least cotton, and the total weight of the polymer based on cellulose is 100% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight of cotton, and more preferably the polymer based on cellulose is cotton.

[0038] Biogas preparation in (e)

[0039] In some embodiments of the method, preparing biogas from the residue of polymer blends according to (e) includes microbial fermentation, more preferably anaerobic microbial fermentation.

[0040] In some embodiments of the method, the residue of the polymer blend is used as a substrate or co-substrate for biogas production in microbial fermentation, preferably anaerobic microbial fermentation.

[0041] Microbial fermentation is also referred to as digestion in this paper. Biogas (methane) production is carried out using anaerobic digesters with existing technology. Common reactor types and process schemes for anaerobic digestion are described in the literature (e.g., Banerjee S, Prasad N, Selvaraju S. Reactor Design for Biogas Production - A Short Review. Journal of Energy and Power Technology 2022; 4(1): 004; doi:10.21926 / jept.2201004.). Suitable reactor types for the anaerobic digestion of polymer blends are, in particular, anaerobic plug flow reactors (APFR), biofilm reactors with moving or fixed beds, continuous flow stirred tank reactors (CSTR), anaerobic contact reactors (ACR), batch reactors, anaerobic baffled reactors (ABR), or hybrid bioreactors. These reactor types can be used as single-stage, two-stage, or multi-stage systems, as well as in combination with different reactor concepts.

[0042] In some embodiments of the method, microbial fermentation, preferably anaerobic microbial fermentation, is carried out at a pH value in the range of 4 to 9, preferably in the range of 4.5 to 8.5, and more preferably in the range of 4.5 to 8.

[0043] Preferably, the pH value, especially in multi-stage systems, varies from pH 4 to pH 9 during the first and subsequent fermentation stages and within the vessel, preferably in the range of 4.5 to 8.5, more preferably in the range of 4.5 to 8. The reactor is operated in a continuous or discontinuous mode with or without stirring or active aeration. Anaerobic digestion of the polymer blend residue is carried out at temperatures ranging from 10°C to 60°C, preferably under psychrophilic (10°C to 30°C), mesophilic (30°C to 40°C), and / or thermophilic (up to 60°C) conditions. The biogas produced by microbial fermentation contains methane and has a composition that changes during anaerobic digestion. Based on a total volume of 100% biogas obtained, the typical composition of biogas is: methane (CH4): in the range of 40 to 70%; carbon dioxide (CO2): in the range of 30 to 60%; other gases: in the range of 1 to 5% (including hydrogen (H2): in the range of 0 to 1% and hydrogen sulfide (H2S): in the range of 0 to 3%).

[0044] The residues of polymer blends can be used as the sole substrate for anaerobic digestion. To improve microbial growth and increase biogas production, one or more enzymes from the classes of cellulase, protease, amylase, pectinase, lipase, and PETase, along with a nutrient solution, can be added to the reactor. Furthermore, trace elements such as iron, zinc, cobalt, nickel, molybdenum, and / or tungsten can be added to the bioreactor to improve microbial growth. Typical trace elements used in anaerobic digestion are listed in the literature, for example, in *Trace Elements in Anaerobic Biotechnologies*, edited by Fernando G. Fermoso, Eric van Hullebusch, Gavin Collins, Jimmy Roussel, Ana Paula Mucha, and Giovanni Esposito, https: / / doi.org / 10.2166 / 9781789060225, ISBN (e.g.): 9781789060225, published by IWA Publishing, 2019; and

[0045] Zhang, Wenxiang Ouyang, Aimin Lia, Essential Role of Trace Elements in Continuous Anaerobic Digestion of Food Waste, Procedia Environmental Sciences, Vol. 16, 2012, pp. 102-111, ISSN 1878-0296, https: / / doi.org / 10.1016 / j.proenv.2012.10.014 More trace elements are listed in Bardi, MJ, Aminirad, H., Synergistic effects of co-trace elements on anaerobic co-digestion of food waste and sewage sludge at high organic load. Environ Sci Pollut Res 27, 18129–18144 (2020). https: / / doi.org / 10.1007 / s11356-020-08252-y.

[0046] Residues from polymer blends can also be added as a co-substrate to anaerobic reactors. The proportion of polymer blend residues within 100% by weight of the total amount of applied feedstock varies from 0.1% by weight to 50% by weight. Suitable feedstocks for biogas production and for use in combination with polymer blend residues are a variety of biodegradable biomass and organic wastes, such as agricultural waste, energy crops, manure and sludge from livestock farming, wastewater treatment sludge, the organic portion of municipal solid waste, food processing waste, waste streams from the beverage industry, cellulose residues from the wood processing and pulp and paper industries, and chemical waste.

[0047] Anaerobic digestion can be carried out with a hydraulic retention time of at least 2 days, more preferably in the range of 20 to 100 days, or even longer, and an organic load in the range of 0.05 to 5 g VS / L / day (VS = volatile solids).

[0048] The resulting biogas contains methane as indicated above and is preferably purified and concentrated, for example, to replace fossil natural gas. Suitable purification methods include, in particular, water washing, cryogenic separation, adsorption (physical and chemical), membrane technology, bio-upgrading, and in-situ upgrading. Various techniques for purifying biogas are described in the following literature, for example, Zăbavă, Bianca-Ștefania & Voicu, Gheorghe & Ungureanu, Nicoleta & Dinca, Mirela & G., Paraschiv & Munteanu, Mariana & Ferdes, Mariana. (2019). Method of Biogas Purification – a review.

[0049] In some embodiments, biogas containing at least 40% methane is used as an energy source, preferably a heat source, for one or more of steps (b) to (d). The biogas is used directly or indirectly as a heat source, i.e., by combustion and using the heat of combustion to produce steam or to generate electricity, which may also be used in one or more of steps (a) to (f) of the method according to the invention.

[0050] In some embodiments, the method includes, after (e)

[0051] (f) Separating methane from the biogas obtained in (e) by one or more purification and / or concentration steps to obtain CH4 with a total volume of 100 vol-% based on the gas phase containing methane (CH4) and a purity of at least 85 vol-%, more preferably at least 90 vol-%, or even more preferably at least 95 vol-%.

[0052] intermediate steps

[0053] In some embodiments, if (b) is performed, the method includes (b) after (b) and before (c).

[0054] (u) Separating the solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof from the residue of a polymer blend depleted in the second polymer and / or colorant and optionally filler or a portion thereof and comprising polyester, optionally cellulose-based third polymer and optionally filler or a portion thereof.

[0055] This results in a separate solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof, and a residue of a separate polymer blend depleted of the second polymer and / or colorant and optionally filler or a portion thereof, and comprising polyester, optionally cellulose-based third polymer and optionally filler or a portion thereof.

[0056] The separation in (u) is preferably carried out by methods and means known to those skilled in the art, especially solid-liquid separation methods such as filtration, for example, heated pressure filtration, sedimentation or centrifugation (see Handbuch der mechanischen Fest-Flüssig-Trennung Taschenbuch [Mechanical Solid-Liquid Separation Handbook] – April 29, 2004 by KlausLuckert (ed.)).

[0057] In some embodiments, if (b) is performed, the method includes, after (b) and before (c):

[0058] (v) Wash the residue of the polymer blend obtained in (b) with a washing solvent to obtain a washed residue that is depleted of the second polymer and / or colorant and optionally filler or a portion thereof and contains polyester, optionally a third polymer and optionally filler or a portion thereof.

[0059] (w) Optionally, the washed residue obtained in (v) is dried.

[0060] In some embodiments, if (b) is performed, the method comprises, after (b), preferably after (u) and before (c):

[0061] (v) Wash the residue of the (separated) polymer blend obtained in (b) or (u) with a washing solvent to obtain a washed residue that is depleted of the second polymer and / or colorant and optionally filler or a portion thereof and contains polyester, optionally a third polymer and optionally filler or a portion thereof.

[0062] (w) Optionally, the washed residue obtained in (v) is dried.

[0063] The washing in optional step (v) is preferably performed using a solvent system having the characteristics (s.1), (s.2), and (s.3) as defined herein, and preferably using a solvent system containing one or more solvents from any of the groups defined herein. Preferably, the washing in optional step (v) is performed using the same solvent system used for (b). In some embodiments, the washing is performed using a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, or a mixture of two or more of these solvents. In some embodiments, the washing in optional step (v) is performed using a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, or a mixture of two or more of these solvents, preferably using a solvent containing at least GVL; more preferably, the washing in optional step (v) is performed using GVL. The drying in optional step (w) is preferably carried out under one or more conditions selected from the group consisting of: a pressure in the range of 1 to 1013 mbar; a temperature in the range of 50°C to 210°C, preferably in the range of 60°C to 180°C, more preferably in the range of 80°C to 160°C; a drying time in the range of 30 minutes to 24 hours; and drying in an atmosphere containing nitrogen, preferably in an atmosphere having at least 90% by volume, more preferably 95% by volume, and more preferably at least 98% by volume. Drying is carried out by one or more methods selected from the group consisting of: contact drying, convection drying, and radiation drying. Contact in step (c) is then carried out based on the residue obtained in the washed (and optionally dried) step (b).

[0064] In some preferred embodiments, the method includes, after (c) and before (d) (if performed), or after (c) and before (e) (if (d) is not performed):

[0065] (w.1) The residue of a polymer blend containing a cellulose-based third polymer and optionally a filler or a portion thereof, obtained in (c) is optionally washed with acetone.

[0066] (w.2) The residue of a polymer blend containing a cellulose-based third polymer and optionally a filler or a portion thereof, obtained by washing with water in (c) or (optionally) in step (w.1);

[0067] The washing in (w.2) is preferably carried out to: the residue of a polymer blend containing a lean polyester and a cellulose-based third polymer and optionally a filler or a portion thereof, having a total weight of 100% by weight, less than 10% by weight, preferably less than 5% by weight, more preferably less than 2% by weight, of one or more organic solvents.

[0068] In some embodiments, the method includes, after (c) and before (d) (if performed) or before (e) steps.

[0069] (x.1) Separating the solvent system obtained in (c) which is rich in dissolved polyester and optionally contains filler or a portion of filler from the residue of the polymer blend, wherein the separation is preferably carried out by heated filtration, more preferably by heated filtration at a temperature T3 (T3 = T2 ± 20°C) in the range of T2 minus 20°C to T2 plus 20°C, and more preferably at a temperature T3 (T3 = T2 ± 10°C) in the range of T2 minus 10°C to T2 plus 10°C, thereby obtaining the separated solvent system rich in dissolved polyester and optionally containing filler or a portion of filler;

[0070] (x.2) Optionally, the residue of the polymer blend obtained in (x.1) is contacted with a solvent system preferably at a temperature T3 as defined above in (x.1), followed by filtration, preferably heated filtration at a temperature T3 as defined above in (x.1), to obtain a residue of a polymer blend that is further lean on polyester and contains a cellulose-based third polymer and optionally a filler or a portion thereof; and a solvent system containing an additional amount of polyester and optionally containing a filler or a portion thereof;

[0071] (x.3) Optionally, the solvent system obtained in (x.2) containing an additional amount of polyester and optionally including filler or a portion of filler is combined with the solvent system separated in (x.1) rich in dissolved polyester and optionally including filler or a portion of filler;

[0072] The precipitation in (d) is based on either the separated solvent system obtained in (x.1) or the combined solvent system obtained in (x.3).

[0073] In heated filtration, the solution, filter, and funnel are heated, preferably to a temperature T3 for each. Other means and methods for separation in (x.1) are known to those skilled in the art, such as non-heated filtration. In some embodiments, it is preferred that heated filtration be carried out at a pressure of ≥ 1 bar, more preferably in the range of 1 to 30 bar, more preferably in the range of 1 to 10 bar, and even more preferably in the range of 1 to 6 bar (heated pressure filtration). Preferably, the filter used in heated filtration is stable under the appropriate conditions and with respect to the appropriate solvent system, especially insoluble or non-degradable. For example, the filter may be made of polyetheretherketone (PEEK).

[0074] Preferably, the contact in (x.2) is performed such that, particularly in the case of heated filtration in (x.1), the residue of the polymer blend obtained in (x.1) remains on the filter and is contacted therewith with the solvent system, wherein the solvent system obtained in (x.2), containing a residual amount of polyester and optionally containing filler or a portion of filler, is separated therefrom due to filtration. In some embodiments, the solvent system obtained in (x.2), containing a residual amount of polyester and optionally containing filler or a portion of filler, is combined with the solvent system obtained in (x.1), which is rich in dissolved polyester and optionally contains filler or a portion of filler.

[0075] In some embodiments, the method includes, after (c) and before step (d) (if performed), or after (c) and before step (e) (if (d) is not performed), and after (x.1) to (x.3) (if performed):

[0076] (x.4) Optionally, the residue of the polymer blend obtained in (x.2) and containing a cellulose-based third polymer and optionally a filler or a portion thereof is washed with acetone to obtain an acetone-washed residue.

[0077] (x.5) The residue of a polymer blend obtained in (x.2) by washing with water and comprising a further lean polyester and optionally a third cellulose-based polymer and a filler or a portion thereof, or the residue obtained in step (x.4) by washing with acetone.

[0078] The washing in (x.5) is preferably carried out until the residue of the polymer blend contains one or more organic solvents with a total weight of 100% by weight, less than 10% by weight, preferably less than 5% by weight, and more preferably less than 2% by weight.

[0079] In some embodiments, the method includes (d) after and before (e).

[0080] (y.1) Separate the precipitated polyester obtained in (d) from the solvent system containing a lean-dissolved polyester and optionally a filler or a portion thereof, thereby obtaining the precipitated polyester and the solvent system containing a lean-dissolved polyester and optionally a filler or a portion thereof.

[0081] (y.2) Optionally wash the precipitated polyester obtained in (y.1);

[0082] (y.3) Dry the precipitated polyester obtained in (y.1) or the washed precipitated polyester obtained in (y.2) to obtain a dried (washed) precipitated polyester.

[0083] The separation in (y.1) is carried out by methods and means known to those skilled in the art, especially solid-liquid separation methods such as filtration, for example, heated pressure filtration, sedimentation or centrifugation (see Handbuch der mechanischen Fest-Flüssig-Trennung Taschenbuch [Mechanical Solid-Liquid Separation Handbook] – April 29, 2004 by Klaus Luckert (editor)). The washing in step (y.1) is preferably carried out with a solvent system having the characteristics (s.1), (s.2) and (s.3) as defined herein, and preferably with a solvent system containing one or more solvents from any of the groups defined herein. In some embodiments, subsequent washing of the washing residue is performed with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, or a mixture of two or more of these solvents, or with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, or a mixture of two or more of these solvents. In some embodiments, the washing in optional step (y.2) is preferably performed with a solvent system having the characteristics (s.1), (s.2), and (s.3) as defined herein, and preferably with a solvent system containing one or more solvents from any group defined herein. In some embodiments, subsequent washing of the washing residue is performed with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, or a mixture of two or more of these solvents, or with a solvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, acetonitrile, ethyl acetate, acetone, water, GVL, or a mixture of two or more of these solvents. The drying in step (y.3) is preferably carried out under one or more conditions selected from the group consisting of: a pressure in the range of 1 to 1013 mbar; a temperature in the range of 50°C to 210°C, preferably in the range of 60°C to 180°C, more preferably in the range of 80°C to 150°C; a drying time in the range of 30 minutes to 24 hours; and drying in an atmosphere containing nitrogen, preferably in an atmosphere having at least 90% by volume, more preferably 95% by volume, and even more preferably at least 98% by volume. The drying is carried out by one or more methods selected from the group consisting of: contact drying, convection drying, and radiation drying.

[0084] In some embodiments, the method includes

[0085] (y.4) The dried (washed) precipitated polyester obtained in (y.3) is granulated to obtain granulated polyester.

[0086] "Granulation" is the process of compressing or molding material into a granular shape. Granulation can be performed as is known in the art, for example, by extrusion followed by underwater granulation or by strand granulation.

[0087] In some embodiments, the method includes (d) after and before (e), preferably after (y.3) or after (y.4) and before (e).

[0088] (z) Increase the intrinsic viscosity of the precipitated polyester obtained in (d) or the dried (washed) precipitated polyester obtained in (y.3) or the granulated polyester obtained in (y.4).

[0089] The increase in intrinsic viscosity according to (z) is carried out in the solid and / or molten state, wherein the increase in intrinsic viscosity increases the molecular weight of the polyester. The increase in intrinsic viscosity is preferably carried out as follows: at a temperature in the range of 200°C to 230°C, more preferably in the range of 200°C to 220°C; and / or, preferably and for a period of time in the range of 1 to 80 hours, preferably 10 to 50 hours; and / or, preferably and for a pressure in the range of 5 to 1013 mbar.

[0090] (d) Precipitation-cooling

[0091] In some embodiments of the method, precipitation in (d) includes cooling the solvent system obtained in (c) which is richer in dissolved polyester than the solvent system provided in (a) from T2 to a temperature below 140°C, wherein the cooling is carried out such that the temperature of the solvent system rich in dissolved polyester is maintained in the temperature range of 160°C to 145°C for a period of time of at least 5 minutes, preferably at least 10 minutes, more preferably in the range of 5 to 120 minutes, more preferably in the range of 10 to 100 minutes, and more preferably in the range of 15 to 100 minutes.

[0092] In some embodiments of the method, cooling is performed in (d) such that the solvent system rich in dissolved polyester has a viscosity in the range of 1 to 12 Pa s, preferably in the range of 1 to 10 Pa s, as determined according to ASTM D445, in the temperature range of 160°C to 145°C.

[0093] In some embodiments of the method, cooling is performed at a cooling rate of ≤ 3.0°C / min, preferably ≤ 1.5°C / min, more preferably in the range of 0.05 to 3.0°C / min, more preferably in the range of 0.13 to 3.0°C / min, more preferably in the range of 0.15 to 1.5°C / min, and even more preferably in the range of 0.15 to 1.0°C / min.

[0094] In some embodiments of the method, the cooling of the solvent system in (d) is carried out from T2 to a temperature below 100°C.

[0095] In some embodiments of the method, the cooling of the solvent system in (d) is carried out at a cooling rate of ≤ 3.0°C / min, preferably ≤ 1.5°C / min, more preferably in the range of 0.05 to 3.0°C / min, more preferably in the range of 0.13 to 3.0°C / min, more preferably in the range of 0.15 to 1.5°C / min, and more preferably in the range of 0.15 to 1.0°C / min from T2 to a temperature below 100°C.

[0096] In some embodiments of the method, the cooling of the solvent system in step (d) is performed without the addition of an antisolvent. An "antisolvent" is a solvent having a solubility of < 1 g / kg of polyester at temperatures ranging from 20°C to 25°C. In some embodiments, only a small amount of one or more antisolvents is added to and / or present in the solvent system in step (d), where a small amount means less than 5% by weight, preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, and more preferably less than 1% by weight of one or more antisolvents based on a total weight of 100% of the solvent system containing one or more antisolvents.

[0097] solvent system

[0098] In some embodiments of the method, the solvent system comprises one or more solvents, wherein

[0099] (s.1) The solvent system has the following Hansen solubility parameters.

[0100] -Energy from the dispersion forces between molecules (δD) ss ),

[0101] -Energy from the dipole intermolecular forces between molecules (δP) ss ),as well as

[0102] -Energy from hydrogen bonds between molecules (δH) ss ),

[0103] It satisfies equation 1

[0104] (8.8)² ≥ 4(δD ss -20)² + (δP ss -11.8)² + (δH ss -4.5)²

[0105] [Equation 1];

[0106] (s.2) Each solvent in the solvent system has a boiling point of at least 160°C at 1013 hPa; and

[0107] (s.3) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), carboxyl (COOH) and mercapto (SH).

[0108] The boiling point of a solvent should be understood as its boiling point under the corresponding pressure. 4(δD) ss -20)² + (δP ss -11.8)²+ (δH ss -4.5)² is greater than (8.8) 2 (i.e., 77.44) No solvent system is suitable for properly dissolving polymers based on polyalkylene terephthalate, and 4(δD ss -20)² + (δP ss -11.8)² + (δH ss -4.5)² is equal to or less than (8.8) 2 Any solvent system (i.e., 77.44) is suitable for dissolving polymers based on polyalkylene terephthalate. In the case where two or more solvents are part of the solvent system, i.e., n solvents, where n is an integer, n ≥ 2 and i = 1…n, the resulting mixture is calculated with respect to δD. ss δH ss and δP ss The Hansen solubility parameter for each of the n solvents (the percentage of each solvent in the solvent system is known) is taken as δD for each S(i) from the n solvents. si δH si and δP si The weighted arithmetic mean. Hansen parameters for the solvent are available in BIOVIA COSMOquick 2022.

[0109] Considering the three-dimensional form given by Equation 1 in three-dimensional Hansen space, it forms a structure centered at δD. c = 20, δP c = 11.8 and δH c= 4.5 and a sphere with radius r of 8.8. According to Charles Hansen, the dispersion parameter value needs to be doubled to achieve the spherical form. Since negative values ​​for δH are impossible, the Hansen sphere can also be considered as a dome, i.e., a hemisphere. PET has Hansen parameters according to version 5.1.03 (2008) of the Hansen solubility parameter (HSPiP) in practice, which are located inside the sphere but not at its center.

[0110] In some embodiments of the method, at least 90% by weight, more preferably at least 95% by weight, more preferably at least 98% by weight, and more preferably at least 99% by weight of the solvent system consists of a solvent system that satisfies Equation 1, wherein when the solvent system consists of only one solvent system, the temperature T is a temperature at least 7 K lower than the boiling temperature of the solvent.

[0111] In some embodiments of the method, a solvent system comprising at least 90 wt%, more preferably at least 95 wt%, more preferably at least 98 wt%, and more preferably at least 99 wt% consists of two or more solvents, wherein the corresponding mixture satisfies Equation 1.

[0112] In some embodiments of this method, one or more solvents are selected from the group consisting of: N,N-dimethylbenzamide, N,N-dimethylphenylacetamide, 1,4-benzoquinone, acetophenone, dimethyl terephthalate, 1,3,5-trimethoxybenzene, 2-phenylacetophenone, N-methylcaprolactam, methyl benzoate, methyl-4-methoxybenzoate, butylene carbonate, N-ethylpyrrolidone, benzophenone, dibenzyl malonate, N... 2-Ethyl-caprolactam, methyl 2-(5-oxotetrahydrofuran-3-yl)acetate (FAME), methyl 2-(5-oxotetrahydrofuran-2-yl)acetate, phenylacetone, N-methoxypropyl-pyrrolidone, 1,4-cyclohexanedione, cyclohexane carbonate, N-methoxyethyl-pyrrolidone, N,N-diethylphenylacetamide, phenyl acetate, 1-(2-hydroxyethyl)pyrrolidone-2-one acetate (HEPAc) N,N-Diethylbenzamide, Isopropyl benzoate, Cyclohexylphenyl ketone, Ethyl phenylacetate, Phenylacetate, N-Methylmorpholine, Benzyl propionate, Benzyl acetate, Neopentyl glycol dibenzoate, Tetrahydrofurfuryl acetate, N-Methylimidazolium, Benzyl butyrate, 2-Pyrrolidone, 2-Phenoxyethanol propionate, 2-Phenoxyethyl isobutyrate, N,N-Dipropylbenzamide, N,N-Dimethyl Acetamide, N,N-diethylacetamide, dihydro-L-glucanone (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerol (GVL), δ-valerol, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyroxyvalerate (Rhodiasolv Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, N,N-dimethyllacticamide (AgniqueAMD 3L), 1,3-dimethyl-2-imidazolium ketone (DMI), and dimethyl sulfoxide (DMSO). In some embodiments of this method, one or more solvents are selected from the group consisting of: dihydro-L-glucosinolate (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerol (GVL), δ-valerol, γ-butyrolactone, dimethyl sulfoxide, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and dimethyl sulfoxide (DMSO).In some embodiments of the method, one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, ethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and GVL. In some embodiments of the method, one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxovalerate (Rhodiasolv® Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, and propyl benzoate. In some embodiments of the method, one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxovalerate (Rhodiasolv® Polarclean), phenethyl acetate, and GVL. In some embodiments of the method, one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopyrrolidone (Rhodiasolv®Polarclean), and phenethyl acetate.

[0113] In some embodiments of this method, ethyl benzoate and butyl benzoate are not included as solvents.

[0114] In some embodiments of the method

[0115] (s.3a) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), secondary amine (-NH-), carboxyl (COOH) and mercapto (SH).

[0116] In some embodiments of the method, one or more solvents are selected from the group consisting of: dihydro-L-glucosidone (Cyrene), methyl phenylacetate, 1,3-dimethyl-2-imidazolium ketone (DMI), dimethyl sulfoxide (DMSO), and GVL. In some embodiments of the method, the solvent system comprises γ-valerolactone (GVL), or dimethyl sulfoxide (DMSO), or a mixture of GVL and DMSO.

[0117] In some embodiments of the method, the solvent system comprises γ-valerolactone, wherein the solvent system comprises γ-valerolactone in a total weight percentage of 100 wt%, more preferably at least 50 wt%, more preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, and more preferably at least 99 wt%.

[0118] In some embodiments of the method, the solvent system comprises dimethyl sulfoxide, wherein the solvent system comprising 100% by weight, more preferably at least 50% by weight, more 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, and more preferably at least 99% by weight is composed of dimethyl sulfoxide.

[0119] In some embodiments of the method, the solvent system comprises γ-valerolactone and dimethyl sulfoxide, wherein the solvent system comprising 100% by weight, more preferably at least 50% by weight, more 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, and more preferably at least 99% by weight is composed of γ-valerolactone and dimethyl sulfoxide.

[0120] Preferably, the solvent system is free of one or more acidic and / or basic components, wherein preferably, the solvent system contains one or more acidic and / or basic components in an amount of less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, and more preferably less than 1% by weight, based on 100% by weight of the total weight of the solvent system. The acidic component is preferably an acid, more preferably an acid selected from the group consisting of organic acids and inorganic acids and mixtures thereof. For example, the acidic component is sulfuric acid, hydrochloric acid, nitric acid, or mixtures thereof. The basic component is preferably a base, more preferably a base selected from the group consisting of organic bases and inorganic bases and mixtures thereof. For example, the basic component is NaOH. All weight-% values ​​indicated for one or more acidic and / or basic components are relative to the dry weight of the one or more acidic and / or basic components.

[0121] In some embodiments of the method, the same solvent system as in (c) is used in optional step (b).

[0122] Polyester

[0123] In some embodiments of the method, the polyester is based on 1,4-butanediol or 1,2-ethylenediol, more preferably the polyester according to (i) is selected from the group consisting of: polymers based on 1,4-butanediol and terephthalic acid (polybutylene terephthalate, PBT), polymers based on 1,2-ethylenediol and terephthalic acid (polyethylene terephthalate, PET), copolymers of 1,4-butanediol, adipic acid and terephthalic acid (polybutylene adipate terephthalate, PBAT), polymers of 1,2-ethylenediol and 2,5-furandicarboxylic acid (polyethylene furandicarboxylate, PEF), and mixtures of two or more of these (co)polymers, more preferably the polyester comprises at least PET and / or PBT, more preferably the polyester is PET or PBT or a mixture of PET and PBT.

[0124] Colorant

[0125] In some embodiments of the method, the colorant is selected from the group consisting of dyes and optical brighteners, and mixtures of dyes and optical brighteners.

[0126] "Colorant" is a substance that causes a change in the color impression of a material. This includes dyes and optical brighteners that absorb the visible light wavelength range (400 to 780 nm), amplifying the material's light emission through UV light absorption and visible light emission (through fluorescence). Specifically, optical brighteners convert radiation invisible to the human eye (< 400 nm) into visible fluorescent radiation in the blue-red spectral range (400 to 600 nm). Colorants that can be used or are used to alter the color impression of polymeric materials are known to those skilled in the art. In the context of this invention, the term "dye" means any kind of dye such as dye, pigment, dispersion, wherein the dye is, for example, one or more selected from the group consisting of: acid dyes, basic dyes, direct dyes, disperse dyes, azo dyes, food dyes, solvent dyes, organic dyes, organic pigments, sulfur dyes, mordant dyes, and vat dyes. The term "optical brightener" includes optical brighteners, fluorescent brighteners, and fluorescent whitening agents.

[0127] An overview of colorants used in polymer materials can be found, for example, in the following literature: "Dyes and Pigments" Metin Açikyildiz, Kübra Günes, Ahmet Gürses Springer [Springer Publishers], 2016 (ISBN: 10: 3319338900); "Industrial Organic Pigments" - Klaus Hunger, Thomas Heber, Martin U. Schmidt, Friedrich Reisinger, Stefan Wanne Wiley-VCH [Wiley-VCH Publishers], 4th edition, 2018 (ISBN: 978-3-527-32608-2); "Chemistry and Technology of Natural and Synthetic Dyes and Pigments" - Ashis Kumar Samanta, Nasser Awwad, IntechOpen Publishers, 2020 (ISBN: 9781789859980, 9781789859973, 9781839687587); Encyclopedia of Color, Dyes, Pigments - Volume 1, Gerhard Pfaff, de Gruyter, 2021 (ISBN: 311058588X); Heinrich Zollinger: Color Chemistry: Syntheses, Properties, and Applications of Organic Dyes and Pigments, 3rd ed. WILEY-VCH Verlag, Weinheim, 2003 (ISBN: 3-906390-23-3); Klaus Hunger (ed.): Industrial Dyes: Chemistry, Properties, Applications [Industrial Dyes: Chemistry, Properties, and Applications]WILEY-VCH Verlag, Weinheim, 2003 (ISBN: 3-662-01950-7); Hermann Rath: Lehrbuch der Textilchemie. einschl. der textilchemischen Technologie [Textbook of Textile Chemistry (including Textile Chemistry Technology)]. 2nd Edition. Springer-Verlag, Berlin, Heidelberg, 1963 (ISBN: 978-3-662-00065-6); Wilfried Kratzert, Rasmus Peichert: Farbstoffe [Dyes]. Quelle & Meyer, Heidelberg, 1981 (ISBN: 3-494-01021-8); Ullmann's Encyclopedia of Industrial Chemistry [Ullman's Encyclopedia of Industrial Chemistry], Wiley-VCH, 2000, sections "dyes and pigments" and "dyes, general survey" (ISBN: 9783527303854).

[0128] Preferably, in step b), only one or more colorants that are not covalently bonded to the polyester are removed from the polymer blend and transferred to the solvent system.

[0129] Second polymer

[0130] In some embodiments of the method, the second polymer is selected from the group consisting of polyurethane (PU), polyethylene glycol (PEG), polytetrahydrofuran (pTHF), mixtures of these polymers and copolymers of these polymers, wherein the second polymer is more preferably PU or a copolymer of PU and PEG and / or pTHF, and more preferably spandex (a copolymer of PU and PEG or PU and pTHF).

[0131] "Spandex" is preferably a copolymer of polyurethane and polyethylene glycol and / or polytetrahydrofuran, and more preferably a copolymer of polyurethane and polyethylene glycol or a copolymer of polyurethane and polytetrahydrofuran.

[0132] filler

[0133] In some embodiments of the method, the filler is selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidant, UV filter, emulsifier, fixative, detergent dispersant, and modifier.

[0134] In some embodiments of the method, the polyester comprises PBT, preferably PBT, and the filler is one or more selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), adhesives, thickeners, defoamers, finishing agents (e.g., waterproofing / oil-repellent / fouling-repellent, flame retardants, anti-wrinkle agents, biocides), binders, surfactants (e.g., softeners, scouring agents, antistatic agents), desizing agents, bleaching agents, oxidants, UV filters, emulsifiers, fixatives, detergent dispersants, and modifiers. Preferably, the filler is one or more selected from glass fiber, coal fiber, carbon black, and inorganic salts (e.g., talc, Na2CO3).

[0135] In some embodiments of the method, the polyester comprises PET, preferably PET, and the filler is one or more selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier, preferably the filler is selected from one or more of the group consisting of: binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier.

[0136] In some embodiments, the article provided in (a) comprises titanium dioxide (TiO2). In these preferred embodiments, the TiO2 is either absent from the precipitated polyester obtained in (d) or present in the precipitated polyester obtained in (d) in an amount ranging from 0.001 to 1.0 wt% based on a total precipitated polyester obtained in (d) of 100 wt%. In these preferred embodiments, the TiO2 (if present) is also present in the fibers prepared in (e).

[0137] Fourth polymer (iv)

[0138] In some embodiments of the method, the polymer blend further comprises a fourth polymer (iv), wherein the fourth polymer is different from the third cellulose-based polymer of polyester (ii), (iii) and the second polymer of (ii), wherein the fourth polymer is selected from polypropylene (PP), polyethylene (PE), polyamide (PA), and mixtures of two or more thereof.

[0139] In some embodiments of the method, the fourth polymer (if present in the polymer blend) is a portion of the residue of the polymer blend obtained in (c) and subjected to biogas preparation in (e)—which is polyester-poor and contains a cellulose-based third polymer and optionally a filler or a portion thereof.

[0140] The presence of a fourth polymer in the residue from biogas production in (e) does not impair microbial fermentation, preferably anaerobic fermentation. The remainder is simply discharged undigested from any biogas reactor.

[0141] Process conditions

[0142] In some embodiments of the method, T1 is a temperature in the range of 110°C to < 170°C, preferably in the range of 110°C to 165°C, more preferably in the range of 120°C to 160°C, even more preferably in the range of 120°C to 150°C, and even more preferably in the range of 151°C to 160°C.

[0143] In some embodiments of the method, T2 is a temperature in the range of >170°C to 200°C, preferably in the range of 175°C to 190°C, and more preferably in the range of 180°C to 190°C.

[0144] In some embodiments of the method, (a), (b), (c), and (d) are performed at pressures in the range of 800 to 200,000 hPa.

[0145] In some embodiments of the method, the contact in (b) lasts for a period of at least 5 minutes, preferably in the range of 5 minutes to 10 hours, more preferably in the range of 5 minutes to 5 hours, and even more preferably in the range of 5 minutes to 4 hours.

[0146] In some embodiments of the method, the contact in (c) lasts for a period of at least 0.1 hours, preferably in the range of 1 minute to 10 hours, more preferably in the range of 1 minute to 2 hours, and even more preferably in the range of 5 minutes to 1 hour.

[0147] In some embodiments of the method, the contact in (b) and / or (c) is carried out in a mass-based ratio solvent system in the range of 1:1 to 100:1, preferably in the range of 1:1 to 20:1: the polymer blend provided in (a) or the residue obtained in (b).

[0148] In some embodiments of the method, at least steps (b) and (c), preferably all steps, are carried out in an inert atmosphere, preferably in the presence of an inert gas, wherein the inert gas is preferably selected from the group consisting of argon, helium, neon, nitrogen, and mixtures of two or more of these inert gases, preferably containing at least nitrogen, and more preferably nitrogen.

[0149] In some embodiments of the method, at least steps (b) and (c), preferably all steps, are performed in batches or sequentially.

[0150] Optional post-processing steps

[0151] In some embodiments, the method further includes post-treating the cellulose-based polymer obtained in (d) or (w.2) or (x.5) prior to (e) by applying one or more treatments selected from the group consisting of:

[0152] - Mechanical processing, preferably selected from the group consisting of: milling, pulping, chopping, tearing, and mixtures of two or more of these processing methods;

[0153] - Heat treatment, preferably selected from the group consisting of: freezing, heating or boiling, and a combination of two or more of these treatments, preferably in combination with the application of excessive pressure (excess pressure = pressure > 1013 mbar);

[0154] - Incubate in an aqueous alkaline solvent, which preferably comprises water and one or more alkaline salts selected from the group consisting of, preferably sodium salts: sodium hydroxide, sodium carbonate, sodium monochloroacetate, and mixtures of two or more thereof;

[0155] - Incubate in an acidic solvent, preferably in one or more acids selected from the group consisting of: sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, and formic acid;

[0156] - Incubation in an ionic liquid, preferably in one or more ionic liquids selected from the group consisting of: 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]), and 1,5-diazabicyclonon-5-enium acetate ([DBNH][OAc]);

[0157] -Incubate in N-methylmorpholine-N-oxide (NMMO);

[0158] -Ultrasonic treatment;

[0159] -radiation;

[0160] - Add an enzyme, preferably selected from the group consisting of: cellulase, protease, pectinase, glucosidase, glucan transferase, PET hydrolase (PET enzyme), and lipase, and mixtures of two or more of these enzymes; more preferably selected from the group consisting of: β-1,4-exoglucanase, β-1,4-endoglucanase, β-1,4-cellobiase, β-glucosidase, pyrolase, and mixtures of two or more of these enzymes; and

[0161] - Microbial culture, preferably by adding cellulose-decomposing bacteria or fungal strains or mixed cultures.

[0162] Preferably, the polymer blend provided in (a) or, optionally, the residue of the polymer blend obtained in (b) is not brought into contact with the acidic and / or basic components before (b), between (b) and (c), and before (c). The acidic component is preferably an acid, more preferably an acid selected from the group consisting of organic acids and inorganic acids and mixtures thereof. For example, the acidic component is sulfuric acid, hydrochloric acid, nitric acid, or mixtures thereof. The basic component is preferably a base, more preferably a base selected from the group consisting of organic bases and inorganic bases and mixtures thereof. For example, the basic component is NaOH. All weight-% values ​​indicated for one or more acidic and / or basic components are relative to the dry weight of one or more acidic and / or basic components. As indicated above, preferably, the residue of the lean polyester obtained in (c) and the polymer blend comprising a cellulose-based third polymer and optionally a filler or a portion thereof comprises one or more acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight. Preferably, the precipitated polyester obtained in (d) comprises one or more acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight.

[0163] The second aspect - biogas derived from cellulose-based polymers

[0164] A second aspect of the invention relates to a method for preparing biogas from a cellulose-based polymer separated from a polymer blend, the method comprising:

[0165] (i) Separating the cellulose-based polymer from a polymer blend comprising a cellulose-based polymer and at least one other polymer different from the cellulose-based polymer, thereby obtaining a separated cellulose-based polymer fraction;

[0166] (ii) Treat the cellulose-based polymer fraction obtained in (i) with a solvent system to obtain the treated cellulose-based polymer fraction;

[0167] (iii) Biogas is prepared from the treated cellulose-based polymer fraction obtained in (ii).

[0168] All the details, examples, and preferred embodiments described above regarding the method of the first aspect, including steps (a), (b), optional steps (c), (d), and (e), are equally applicable to the method of the second aspect for preparing biogas from cotton separated from the polymer blend. "At least one additional polymer" preferably refers to the second polymer as defined above. In particular, the polymer blend or the separated cellulose-based polymer fraction is not contacted with the acidic and / or basic components before, during, or between steps (i) and (ii). Preferably, the solvent system used in (ii) is free of acidic and / or basic components, wherein preferably, the solvent system contains acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight.

[0169] In some embodiments, a method for preparing biogas from a cellulose-based polymer separated from a polymer blend includes:

[0170] (i) Separating the cellulose-based polymer from a polymer blend comprising a cellulose-based polymer and at least one other polymer different from the cellulose-based polymer, thereby obtaining a separated cellulose-based polymer fraction;

[0171] (ii) The cellulose-based polymer fraction obtained in (i) is treated with a solvent system comprising γ-valerol (GVL) or dimethyl sulfoxide (DMSO) or a mixture of GVL and DMSO to obtain a treated cellulose-based polymer fraction, wherein the solvent system comprises one or more acidic and / or basic components in a total weight of 100 wt%, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%.

[0172] (iii) Biogas is prepared from the treated cellulose-based polymer fraction obtained in (ii);

[0173] Before step (i), during step (i), and between steps (i) and (ii), the polymer blend or the separated cellulose-based polymer fraction is not brought into contact with the acidic and / or alkaline components.

[0174] The acidic component is preferably an acid, more preferably an acid selected from the group consisting of organic acids and inorganic acids and mixtures thereof. For example, the acidic component is sulfuric acid, hydrochloric acid, nitric acid, or mixtures thereof. The basic component is preferably a base, more preferably a base selected from the group consisting of organic bases and inorganic bases and mixtures thereof. For example, the basic component is NaOH.

[0175] Preferably, the treated cellulose-based polymer fraction obtained in (ii) comprises one or more acidic and / or basic components based on a total weight of 100 wt% of the treated cellulose-based polymer fraction, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%.

[0176] Preferably, the solvent system comprises γ-valerolactone, wherein the solvent system comprises γ-valerolactone in a total weight percentage of 100% by weight, more preferably at least 50% by weight, more 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, and more preferably at least 99% by weight.

[0177] The third aspect - biogas

[0178] The third aspect of the invention relates to biogas, preferably methane-containing biogas, which is obtained or can be obtained by the methods of the first or second aspect. All details, embodiments, and preferred embodiments described above with respect to the methods of the first or second aspect also apply to the third aspect.

[0179] Fourth aspect - Application

[0180] A fourth aspect of the invention relates to the use of biogas, preferably containing methane—preferably after purification and / or concentration—as a carbon and / or hydrogen source according to the third aspect. The fourth aspect also relates to the use of biogas, preferably containing at least 40% methane, as an energy source, preferably a thermal energy source, for one or more of steps (b) to (d). The biogas can be used directly or indirectly as a thermal energy source, for example, by combustion and using the heat of combustion to produce steam or to generate electricity, which can then be used in the method according to the invention.

[0181] All the details, embodiments, and preferred embodiments described above with respect to the methods of the first, second, or third aspects also apply to the fourth aspect.

[0182] Fifth aspect - Polyester

[0183] The fifth aspect of the invention relates to a polyester that is obtained or can be obtained by the method of the first or second aspect.

[0184] All the details, embodiments, and preferred embodiments described above regarding the methods of the first to fourth aspects also apply to the fifth aspect.

[0185] 6th aspect - Applications

[0186] The sixth aspect of the invention relates to the use of the polyester of the fifth aspect in textile applications, fiber applications, packaging applications, plastic applications, automotive applications, and electronic applications, preferably in the production of food packaging, beverage packaging, clothing, footwear, wires, and cables, wherein it is preferably used in textile applications, fiber applications, packaging applications, and plastic applications, and more preferably in the production of food packaging, beverage packaging, clothing, and footwear. All details, embodiments, and preferred embodiments described above with respect to the methods of the first to fifth aspects also apply to the sixth aspect.

[0187] Aspect 7 - Methods for Preparing Products

[0188] The seventh aspect of the present invention relates to a method for preparing a product, the method comprising:

[0189] (I) Provide a polyester that is obtained or available by the method of the first or second aspect;

[0190] (II) Textiles, fibers, packaging, plastics, automotive parts, and electronic parts are made from the polyester provided in (I).

[0191] All the details, embodiments, and preferred embodiments described above regarding the methods of the first to sixth aspects also apply to the seventh aspect.

[0192] Aspect 8 - Focusing on methods for obtaining fractions containing a second polymer.

[0193] The eighth aspect relates to the methods of the first aspect, wherein (b) includes:

[0194] (b.1) Contacting the polymer blend with a solvent system at a temperature T1 < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally filler or a portion thereof, and a residue of a polymer blend depleted of the second polymer and / or colorant and optionally filler or a portion thereof and comprising polyester, optionally cellulose-based third polymer and optionally filler or a portion thereof;

[0195] (b.2) Separating the solvent system obtained in (b.1) rich in dissolved second polymer and / or colorant and optionally filler or a portion of filler from the residue—preferably by a physical separation method, thereby obtaining a separated solvent system richer in dissolved second polymer and / or colorant and optionally filler or a portion of filler compared to the solvent system provided in (a); and

[0196] (b.3) Separate the second polymer from the solvent system to obtain a separated fraction containing the second polymer.

[0197] All the details, embodiments, and preferred embodiments described above regarding the methods of the first to seventh aspects also apply to the eighth aspect.

[0198] Aspect 9 - Focusing on methods for converting second polymers and / or reclaimed polyesters

[0199] The ninth aspect of the present invention relates to a method, preferably according to the first or second aspect, comprising the following additional steps:

[0200] - Convert the second polymer and / or the re-obtained polyester.

[0201] To obtain one or more monomers, polymers, or polymer products.

[0202] All the details, embodiments, and preferred embodiments described above with respect to the methods of the first to eighth aspects also apply to the ninth aspect.

[0203] Preferably, the monomer is a diol or polyol, preferably butanediol; an aldehyde, preferably formaldehyde; a diisocyanate or polyisocyanate, preferably methylene diphenyl diisocyanate (MDI), polymeric methylene diphenyl diisocyanate (pMDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI); an amide, preferably caprolactam; an olefin, preferably styrene, ethylene and norbornene; an alkyne; a (di) ester, preferably methyl methacrylate; a monoacid or diacid, preferably adipic acid or terephthalic acid; a diamine, preferably hexamethylenediamine or nonadiamine; or a sulfone, preferably 4,4'-dichlorodiphenyl sulfone.

[0204] Preferably, the polymer and / or polymer product comprises 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 polyacrylate (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene) -Isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate (PBAT), polyester (PES), polyethersulfone (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulfone (PSU), polyphenylene sulfone (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene ether) (PPO), poly(p-phenylene ether) (PPE); or copolymers or mixtures thereof.

[0205] Preferably, the polymer and / or polymer product is one or more of the following:

[0206] - Automotive parts; preferably cylinder head covers, engine hoods, turbocharger housings, turbocharger baffles, intake pipes, intake manifolds, connectors, gears, fan wheels, coolant tanks, housings, heat exchanger housings, coolant coolers, turbocharger coolers, thermostats, water pumps, radiators, fasteners, battery system components for electric vehicles, dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C, or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper protective housings, decorative grilles, covers, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushioning pads or coatings;

[0207] - Fabric; preferably shirts, trousers, sweaters, boots, shoes, shoe soles, bodysuits or jackets;

[0208] - Electrical components; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foil, wire, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, spools, lamps, diodes, LEDs, transistors, connectors, voltage regulators, integrated circuits (ICs), processors, controllers, memory, sensors, microswitches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, gaskets, bolts, strips, slide-in guides, screws, nuts, membrane hinges, spring hooks (clamp-in) or spring tongues;

[0209] - Consumer goods, agricultural products, or pharmaceutical products; preferably tennis strings, climbing ropes, bristles, brushes, artificial turf, 3D printed filaments, lawnmowers, zippers, hook and loop fasteners, paper machine netting, extrusion coatings, fishing lines, fishing nets, offshore lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyors, sliding bearings, rollers, wheels, gears, ring gears, screws and spring dampers, hoses, pipes, cable sheaths, sockets, switches, cable ties, fan wheels, carpets, cosmetic boxes or bottles, mattresses, cushioning pads, insulating materials, detergents, dishwasher detergent blocks or powders, shampoos, shower gels, bath gels, soaps, fertilizers, fungicides, or pest control agents;

[0210] - For packaging in the food industry, single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film, or laminated film are preferred; or

[0211] - Structural components, preferably rotor blades, insulating materials, frames, housings, walls, coatings, or partition walls.

[0212] Preferably, the content of the second polymer and / or polyester polymer in the monomer, polymer, and / or polymer product is 1% by weight or more, preferably 2% by weight or more, more preferably 5% by weight or more, more preferably 15% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 60% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more, more preferably 95% by weight or more; and / or

[0213] The content of the second polymer and / or polyester in the monomer, polymer, and / or polymer product is 100% by weight or less, preferably 95% by weight or less, more preferably 90% by weight or less, more preferably 50% by weight or less, more preferably 25% by weight or less, and more preferably 10% by weight or less; and

[0214] Preferably, the content is determined based on an identity preservation and / or segregation and / or quality balance and / or ledger and declaration chain of custody model, preferably based on quality balance, preferred International Sustainability and Carbon Certification (ISCC) standards.

[0215] The invention is further illustrated by the following set of embodiments and combinations of embodiments derived from the dependent relationships and reverse references shown. In particular, it should be noted that in each instance of reference to a series of embodiments, such as in the context of the term "method as described in any one of Embodiments 1 to 4," each embodiment in this series is intended to clearly disclose to those skilled in the art that the wording of this term should be understood by those skilled in the art to be synonymous with "method as described in any one of Embodiments 1, 2, 3, and 4." Furthermore, it should be clearly noted that the following set of embodiments represents appropriate structural portions of the general description of preferred aspects of the invention and therefore appropriately supports, but does not represent, the claims of the invention.

[0216] 1. A method for producing biogas, the method comprising:

[0217] Provides a polymer blend comprising

[0218] (i) Polyester, and

[0219] (ii) Optionally, one or more components selected from the group consisting of a second polymer, a colorant, and a filler;

[0220] (iii) Cellulose-based third polymers;

[0221] The optional second polymer (ii) and the cellulose-based third polymer (iii) are different from each other and different from the polyester of (i);

[0222] The method includes:

[0223] (a) Provide the polymer blend and the solvent system;

[0224] (b) Optionally, the polymer blend is contacted with the solvent system at a temperature T1 < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally the filler or a portion thereof, and a residue of the polymer blend depleted in the second polymer and / or colorant and optionally the filler or a portion thereof and containing the polyester, optionally the cellulose-based third polymer and optionally the filler or a portion thereof;

[0225] (c) Contact the residue of the polymer blend provided in (a) or optionally the polymer blend obtained in (b) with a solvent system at a temperature T2 > 170°C to obtain a solvent system rich in dissolved polyester and optionally containing the filler or a portion thereof compared to the solvent system provided in (a), and a residue of the polymer blend that is polyester-poor and contains the cellulose-based third polymer and optionally the filler or a portion thereof;

[0226] (d) Optionally, the polyester is precipitated from the solvent system rich in dissolved polyester obtained in (c), thereby obtaining a solvent system containing precipitated polyester and dissolved polyester and optionally the filler or a portion thereof.

[0227] (e) Prepare biogas from the residue of the polymer blend obtained in (c) and comprising the cellulose-based third polymer and optionally the filler or a portion thereof.

[0228] 2. The method as described in Example 1, wherein the cellulose-based third polymer is selected from the group consisting of: polymers based on natural cellulose, polymers based on synthetic cellulose, and mixtures of one or more polymers based on natural cellulose and one or more polymers based on synthetic cellulose, wherein the polymer based on natural cellulose is preferably selected from the group consisting of: cotton, cellulose, lignin, linseed, viscose fiber, and mixtures of two or more thereof, and wherein the polymer based on synthetic cellulose is preferably viscose fiber, wherein the polymer based on cellulose preferably contains at least cotton, and the total weight of the polymer based on cellulose is 100% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, wherein the polymer based on cellulose is cotton, and more preferably the polymer based on cellulose is cotton.

[0229] 3. The method as described in Example 1 or 2, wherein preparing biogas from the residue of the polymer blend according to (e) includes microbial fermentation, more preferably anaerobic microbial fermentation.

[0230] 4. The method as described in Example 3, wherein the residue of the polymer blend is used as a substrate or co-substrate for biogas production in microbial fermentation, preferably anaerobic microbial fermentation.

[0231] 5. The method as described in Example 3 or 4, wherein the microbial fermentation, preferably anaerobic microbial fermentation, is carried out at a pH value in the range of 4 to 9, preferably in the range of 4.5 to 8.5, and more preferably in the range of 4.5 to 8.

[0232] 6. The method as described in any one of Examples 1 to 5, wherein the method includes, after (e),

[0233] (f) Methane is separated from the biogas obtained in (e) by one or more purification and / or concentration steps, thereby obtaining CH4 with a total volume of 100 vol-% based on the gas phase containing methane (CH4) and a purity of at least 85 vol-%, more preferably at least 90 vol-%, or even more preferably at least 95 vol-%.

[0234] 7. The method as described in any one of Examples 1 to 6, wherein if (b) is performed, the method comprises, after (b) and before (c):

[0235] (v) Wash the residue of the polymer blend obtained in (b) with a washing solvent to obtain a washed residue that is depleted of the second polymer and / or colorant and optionally the filler or a portion thereof and contains the polyester, optionally the third polymer and optionally the filler or a portion thereof.

[0236] (w) Optionally, the washed residue obtained in (v) is dried.

[0237] 8. The method as described in any one of Examples 1 to 7, wherein the method comprises, after (c) and before (d) (if performed), or after (c) and before (e) (if (d) is not performed):

[0238] (w.1) Optionally, the residue of the polymer blend obtained in (c) is washed with acetone and comprising the cellulose-based third polymer and optionally the filler or a portion thereof;

[0239] (w.2) The residue of the polymer blend obtained in (c) or optionally in step (w.1) and containing the cellulose-based third polymer and optionally the filler or a portion thereof;

[0240] The washing in (w.2) is preferably carried out until the residue of the polymer blend containing lean polyester and the cellulose-based third polymer and optionally the filler or a portion thereof contains 100% by weight, less than 10% by weight, preferably less than 5% by weight, more preferably less than 2% by weight of one or more organic solvents.

[0241] 9. The method as described in any one of Examples 1 to 8, wherein the method includes, after (c) and before (d) (if performed) or before (e), steps 1 to 8.

[0242] (x.1) The solvent system obtained in (c) which is rich in dissolved polyester and optionally contains the filler or a portion thereof, is separated from the residue of the polymer blend, wherein the separation is preferably carried out by heated filtration, more preferably by heated filtration at a temperature T3 (T3 = T2 ± 20°C) in the range of T2 minus 20°C to T2 plus 20°C, and more preferably at a temperature T3 (T3 = T2 ± 10°C) in the range of T2 minus 10°C to T2 plus 10°C, thereby obtaining the separated solvent system rich in dissolved polyester and optionally containing the filler or a portion thereof;

[0243] (x.2) Optionally, the residue of the polymer blend obtained in (x.1) is contacted with a solvent system preferably at a temperature T3 as defined above in (x.1), followed by filtration, preferably heated filtration at a temperature T3 as defined above in (x.1), to obtain a residue of the polymer blend that is further lean on polyester and contains the cellulose-based third polymer and optionally the filler or a portion thereof; and a solvent system containing an additional amount of the polyester and optionally containing the filler or a portion thereof;

[0244] (x.3) Optionally, the solvent system obtained in (x.2) containing the additional amount of polyester and optionally including the filler or a portion of the filler is combined with the solvent system separated in (x.1) rich in dissolved polyester and optionally including the filler or a portion of the filler;

[0245] The precipitation in (d) is based on the separate solvent system obtained in (x.1) or the combined solvent system obtained in (x.3).

[0246] 10. The method as described in any one of Examples 1 to 9, wherein the method includes (d) after and before (e).

[0247] (y.1) Separate the precipitated polyester obtained in (d) from the solvent system containing a lean-dissolved polyester and optionally the filler or a portion thereof, thereby obtaining the precipitated polyester and the solvent system containing a lean-dissolved polyester and optionally the filler or a portion thereof;

[0248] (y.2) Optionally, the precipitated polyester obtained in (y.1) is washed;

[0249] (y.3) Dry the precipitated polyester obtained in (y.1) or the washed precipitated polyester obtained in (y.2) to obtain a dried (washed) precipitated polyester;

[0250] (y.4) Optionally, the dried (washed) precipitated polyester obtained in (y.3) is granulated to obtain granulated polyester.

[0251] 11. The method as described in any one of Examples 1 to 10, wherein the method comprises, after (d) and before (e), preferably after (y.3) or after (y.4) and before (e), the following steps:

[0252] (z) Increase the intrinsic viscosity of the precipitated polyester obtained in (d) or the dried (washed) precipitated polyester obtained in (y.3) or the granulated polyester obtained in (y.4).

[0253] 12. The method of any one of Examples 1 to 11, wherein precipitation in (d) comprises cooling the solvent system obtained in (c) which is richer in dissolved polyester than the solvent system provided in (a) from T2 to a temperature below 140°C, wherein the cooling is carried out such that the temperature of the solvent system rich in dissolved polyester is maintained in the temperature range of 160°C to 145°C for a period of time of at least 5 minutes, preferably at least 10 minutes, more preferably in the range of 5 to 120 minutes, more preferably in the range of 10 to 100 minutes, and more preferably in the range of 15 to 100 minutes.

[0254] 13. The method as described in Example 12, wherein cooling is performed in (d) such that the solvent system rich in dissolved polyester has a viscosity in the range of 1 to 12 Pas, preferably in the range of 1 to 10 Pas, as determined according to ASTM D445, in the temperature range of 160°C to 145°C.

[0255] 14. The method as described in Example 12 or 13, wherein cooling is performed at a cooling rate of ≤ 3.0°C / min, preferably ≤ 1.5°C / min, more preferably in the range of 0.05 to 3.0°C / min, more preferably in the range of 0.13 to 3.0°C / min, more preferably in the range of 0.15 to 1.5°C / min, and even more preferably in the range of 0.15 to 1.0°C / min.

[0256] 15. The method as described in any one of Examples 12 to 14, wherein the cooling of the solvent system in (d) is performed from T2 to a temperature below 100°C.

[0257] 16. The method as described in any one of Examples 12 to 15, wherein the cooling of the solvent system in (d) is carried out without the addition of an antisolvent.

[0258] 17. The method as described in any one of Examples 1 to 16, wherein the solvent system comprises one or more solvents, wherein,

[0259] (s.1) This solvent system has the following Hansen solubility parameters.

[0260] -Energy from the dispersion forces between molecules (δD) ss ),

[0261] -Energy from the dipole intermolecular forces between molecules (δP) ss ),as well as

[0262] -Energy from hydrogen bonds between molecules (δH) ss ),

[0263] It satisfies equation 1

[0264] (8.8)² ≥ 4(δD ss -20)² + (δP ss -11.8)² + (δH ss -4.5)²

[0265] [Equation 1];

[0266] (s.2) Each solvent in the solvent system has a boiling point of at least 160°C at 1013 hPa; and

[0267] (s.3) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), carboxyl (COOH) and mercapto (SH).

[0268] 18. The method as described in any one of Examples 1 to 17, wherein at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight, and even more preferably at least 99% by weight, of the solvent system comprises two or more solvents, wherein the corresponding mixtures satisfy Equation 1.

[0269] 19. The method of any one of Examples 1 to 18, wherein the one or more solvents are selected from the group consisting of: N,N-dimethylbenzamide, N,N-dimethylphenylacetamide, 1,4-benzoquinone, acetophenone, dimethyl terephthalate, 1,3,5-trimethoxybenzene, 2-phenylacetophenone, N-methylcaprolactam, methyl benzoate, methyl-4-methoxybenzoate, butylene carbonate, N-ethylpyrrolidone, Benzophenone, dibenzyl malonate, N-ethylcaprolactam, methyl 2-(5-oxotetrahydrofuran-3-yl)acetate (FAME), methyl 2-(5-oxotetrahydrofuran-2-yl)acetate, acetone, N-methoxypropylpyrrolidone, 1,4-cyclohexanedione, cyclohexane carbonate, N-methoxyethylpyrrolidone, N,N-diethylphenylacetamide, phenyl acetate, 1-(2-hydroxyethyl)pyrrolidone-2 HEPAc (a type of ketone acetate), N,N-diethylbenzamide, isopropyl benzoate, cyclohexylphenyl ketone, ethyl phenyl acetate, phenyl acetate, N-methylmorpholine, benzyl propionate, benzyl acetate, neopentyl glycol dibenzoate, tetrahydrofurfuryl acetate, N-methylimidazolium, benzyl butyrate, 2-pyrrolidone, 2-phenoxyethanol propionate, 2-phenoxyethyl isobutyrate, N,N-dipropylbenzamide, N,N-dimethylethyl... Amides, N,N-diethylacetamide, dihydro-L-glucanone (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerolactone (GVL), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, N,N-dimethyllactic acid amide (Agnique AMD 3L), 1,3-dimethyl-2-imidazolium ketone (DMI), and dimethyl sulfoxide (DMSO).

[0270] 20. The method of any one of Examples 1 to 19, wherein the one or more solvents are selected from the group consisting of: dihydro-L-glucosinolate (Cyrene), propylene carbonate, caprolactone, dimethyl isosorbide, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), γ-valerolactone (GVL), δ-valerolactone, γ-butyrolactone, dimethyl sulfoxide, methyl 5-(dimethylamino)-2-methyl-5-oxopyrrolidone (Rhodiasolv®Polarclean), caprolactam, phenethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and dimethyl sulfoxide (DMSO).

[0271] 21. The method of any one of Examples 1 to 20, wherein the one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, ethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, propyl benzoate, and GVL.

[0272] 22. The method of any one of Examples 1 to 21, wherein the one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), δ-valerolactone, γ-butyrolactone, methyl 5-(dimethylamino)-2-methyl-5-oxopyranoate (Rhodiasolv®Polarclean), caprolactam, ethyl acetate, methyl phenylacetate, benzyl benzoate, phenyl benzoate, methyl benzoate, and propyl benzoate.

[0273] 23. The method of any one of Examples 1 to 22, wherein the one or more solvents in the solvent system are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopyrrolidone (Rhodiasolv®Polarclean), phenethyl acetate and GVL.

[0274] 24. The method of any one of Examples 1 to 23, wherein the one or more solvents are selected from the group consisting of: propylene carbonate, N-butylpyrrolidone, tert-butylpyrrolidone, methyl-1-methyl-5-oxopyrrolidone-3-carboxylate (MMOC), methyl 5-(dimethylamino)-2-methyl-5-oxopyrrolidone (Rhodiasolv®Polarclean), and phenethyl acetate.

[0275] 25. The method as described in any one of Examples 1 to 24, wherein ethyl benzoate and butyl benzoate are excluded as solvents.

[0276] 26. The method as described in any one of Examples 1 to 25, wherein,

[0277] (s.3a) Solvents that do not include functional groups selected from the group consisting of: hydroxyl (OH), amino (NH2), secondary amine (-NH-), carboxyl (COOH) and mercapto (SH).

[0278] 27. The method of any one of Examples 1 to 26, wherein the one or more solvents are selected from the group consisting of: dihydro-L-glucosidone (Cyrene), methyl phenylacetate, 1,3-dimethyl-2-imidazolium ketone (DMI), dimethyl sulfoxide (DMSO), and GVL.

[0279] 28. The method as described in any one of Examples 1 to 27, wherein the one or more solvents are GVL or dimethyl sulfoxide (DMSO) or a mixture of GVL and DMSO.

[0280] 29. The method of any one of Examples 1 to 28, wherein the solvent system comprises γ-valerolactone, wherein the solvent system comprises γ-valerolactone based on a total weight of 100 wt% more preferably at least 50 wt%, more preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 99 wt%.

[0281] 30. The method of any one of Examples 1 to 29, wherein the solvent system comprises dimethyl sulfoxide (DMSO), wherein the solvent system comprises DMSO at a total weight of 100 wt%, more preferably at least 50 wt%, more preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 99 wt%.

[0282] 31. The method of any one of Examples 1 to 30, wherein the solvent system comprises γ-valerol (GVL) and dimethyl sulfoxide (DMSO), wherein the solvent system comprises 100% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, more preferably at least 99% by weight.

[0283] 32. The method as described in any one of Examples 1 to 31, wherein the solvent system does not contain one or more acidic and / or basic components, wherein preferably, the solvent system contains one or more acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight.

[0284] 33. The method of any one of Examples 1 to 32, wherein the residue of the polymer blend of the lean polyester obtained in (c) and comprising the cellulose-based third polymer and optionally the filler or a portion of the filler comprises one or more acidic and / or basic components in a total weight of 100 wt%, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%; and / or wherein the precipitated polyester obtained in (d) comprises one or more acidic and / or basic components in a total weight of 100 wt%, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%.

[0285] 34. The method as described in any one of Examples 1 to 33, wherein, in optional step (b), the same solvent system as in (c) is used.

[0286] 35. The method of any one of Examples 1 to 34, wherein the polyester is based on 1,4-butanediol or 1,2-ethylenediol, more preferably the polyester according to (i) is selected from the group consisting of: polymers based on 1,4-butanediol and terephthalic acid (polybutylene terephthalate, PBT), polymers based on 1,2-ethylenediol and terephthalic acid (polyethylene terephthalate, PET), copolymers of 1,4-butanediol, adipic acid and terephthalic acid (polybutylene adipate terephthalate, PBAT), polymers of 1,2-ethylenediol and 2,5-furandicarboxylic acid (polyethylene furandicarboxylate, PEF), and mixtures of two or more of these (co)polymers, more preferably the polyester comprises at least PET and / or PBT, more preferably the polyester is PET or PBT or a mixture of PET and PBT.

[0287] 36. The method of any one of Examples 1 to 35, wherein the colorant is selected from the group consisting of dyes and optical brighteners and mixtures of dyes and optical brighteners.

[0288] 37. The method of any one of Examples 1 to 36, wherein the second polymer is selected from the group consisting of polyurethane (PU), polyethylene glycol (PEG), polytetrahydrofuran (pTHF), mixtures of these polymers and copolymers of these polymers, wherein the second polymer is more preferably PU or a copolymer of PU and PEG and / or pTHF, more preferably spandex (a copolymer of PU and PEG or PU and pTHF).

[0289] 38. The method of any one of Examples 1 to 37, wherein the filler is selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing agent / oil repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier.

[0290] 39. The method of Example 38, wherein the polyester comprises PBT, preferably PBT, and the filler is one or more selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), adhesives, thickeners, defoamers, finishing agents (e.g., waterproofing / oil-repellent / fouling agents, flame retardants, anti-wrinkle agents, biocides), binders, surfactants (e.g., softeners, scouring agents, antistatic agents), desizing agents, bleaching agents, oxidants, UV filters, emulsifiers, fixatives, detergent dispersants, and modifiers, preferably the filler is one or more selected from glass fiber, coal fiber, carbon black, and inorganic salts (e.g., talc, Na2CO3).

[0291] 40. The method of Example 39, wherein the polyester comprises PET, preferably PET, and the filler is one or more selected from the group consisting of: glass fiber, coal fiber, carbon black, inorganic salts (e.g., talc, sodium carbonate), binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier, preferably the filler is selected from one or more of the group consisting of: binder, thickener, defoamer, finishing agent (e.g., waterproofing / oil-repellent / fouling agent, flame retardant, anti-wrinkle agent, biocide), adhesive, surfactant (e.g., softener, scouring agent, antistatic agent), desizing agent, bleaching agent, oxidizing agent, UV filter, emulsifier, fixative, detergent dispersant, modifier.

[0292] 41. The method of any one of Examples 1 to 40, wherein the polymer blend further comprises a fourth polymer (iv), wherein the fourth polymer is different from the third cellulose-based polymer of the polyester (ii), (iii) and the second polymer of (ii), wherein the fourth polymer is selected from polypropylene (PP), polyethylene (PE), polyamide (PA), and mixtures of two or more thereof.

[0293] 42. The method as described in Example 41, wherein the fourth polymer (if present in the polymer blend) is a part of the residue of the polymer blend obtained in (c) and subjected to biogas preparation in (e)—its lean polyester and comprising the cellulose-based third polymer and optionally the filler or a portion thereof.

[0294] 43. The method as described in any one of Examples 1 to 42, wherein T1 is a temperature in the range of 110°C to < 170°C, preferably in the range of 110°C to 165°C, more preferably in the range of 120°C to 160°C, more preferably in the range of 120°C to 150°C, and even more preferably in the range of 151°C to 160°C.

[0295] 44. The method as described in any one of Examples 1 to 43, wherein T2 is a temperature in the range of >170°C to 200°C, preferably in the range of 175°C to 190°C, and more preferably in the range of 180°C to 190°C.

[0296] 45. The method as described in any one of Examples 1 to 44, wherein (a), optionally (b), (c) and optionally (d) are performed at a pressure in the range of 800 to 200,000 hPa.

[0297] 46. ​​The method as described in any one of Examples 1 to 45, wherein the contact in (b) is performed for a period of at least 5 minutes, preferably in the range of 5 minutes to 10 hours, more preferably in the range of 5 minutes to 5 hours, and even more preferably in the range of 5 minutes to 4 hours.

[0298] 47. The method as described in any one of Examples 1 to 46, wherein the contact in (c) is performed for a period of at least 0.1 hours, preferably in the range of 1 minute to 10 hours, more preferably in the range of 1 minute to 2 hours, and even more preferably in the range of 5 minutes to 1 hour.

[0299] 48. The method of any one of Examples 1 to 47, wherein the contact in (b) and / or (c) is carried out in a mass-based ratio solvent system in the range of 1:1 to 100:1, preferably in the range of 1:1 to 20:1: the polymer blend provided in (a) or the residue obtained in (b).

[0300] 49. The method as described in any one of Examples 1 to 48, wherein at least steps (b) and (c), preferably all steps, are carried out in an inert atmosphere, preferably in the presence of an inert gas, wherein the inert gas is preferably selected from the group consisting of argon, helium, neon, nitrogen, and mixtures of two or more of these inert gases, preferably containing at least nitrogen, more preferably nitrogen.

[0301] 50. The method as described in any one of Examples 1 to 49, wherein at least steps (b) and (c), preferably all steps, are performed in batches or sequentially.

[0302] 51. The method of any one of Examples 1 to 50, further comprising post-treating the cellulose-based polymer obtained in (d) or (w.2) prior to (e) by applying one or more treatments selected from the group consisting of:

[0303] - Mechanical processing, preferably selected from the group consisting of: milling, pulping, chopping, tearing, and mixtures of two or more of these processing methods;

[0304] - Heat treatment, preferably selected from the group consisting of: freezing, heating or boiling, and a combination of two or more of these treatments, preferably in combination with the application of excessive pressure (excess pressure = pressure > 1013 mbar);

[0305] - Incubate in an aqueous alkaline solvent, which preferably comprises water and one or more alkaline salts selected from the group consisting of, preferably sodium salts: sodium hydroxide, sodium carbonate, sodium monochloroacetate, and mixtures of two or more thereof;

[0306] - Incubate in an acidic solvent, preferably in one or more acids selected from the group consisting of: sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, and formic acid;

[0307] - Incubation in an ionic liquid, preferably in one or more ionic liquids selected from the group consisting of: 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]), and 1,5-diazabicyclonon-5-enium acetate ([DBNH][OAc]);

[0308] -Incubate in N-methylmorpholine-N-oxide (NMMO);

[0309] -Ultrasonic treatment;

[0310] -radiation;

[0311] - Add an enzyme, preferably selected from the group consisting of: cellulase, protease, pectinase, glucosidase, glucan transferase, PET hydrolase (PET enzyme), and lipase, and mixtures of two or more of these enzymes; more preferably selected from the group consisting of: β-1,4-exoglucanase, β-1,4-endoglucanase, β-1,4-cellobiase, β-glucosidase, β-glucanase, and mixtures of two or more of these enzymes; and

[0312] - Microbial culture, preferably by adding cellulose-decomposing bacteria or fungal strains or mixed cultures.

[0313] 52. The method as described in any one of Examples 1 to 51, wherein the polymer blend provided in (a) or the residue of the polymer blend obtained optionally in (b) is not contacted with the acidic component and / or the basic component before (b), between (b) and (c), and before (c).

[0314] 53. A method for preparing biogas from a cellulose-based polymer separated from a polymer blend, the method comprising:

[0315] (i) Separating the cellulose-based polymer from a polymer blend comprising a cellulose-based polymer and at least one other polymer different from the cellulose-based polymer, thereby obtaining a separated cellulose-based polymer fraction;

[0316] (ii) Treat the cellulose-based polymer fraction obtained in (i) with a solvent system to obtain a treated cellulose-based polymer fraction;

[0317] (iii) Biogas is prepared from the treated cellulose-based polymer fraction obtained in (ii).

[0318] 54. The method as described in Example 53, wherein the polymer blend or the separated cellulose-based polymer fraction is not contacted with the acidic and / or alkaline components before, during, and between steps (i) and (ii).

[0319] 55. The method as described in Example 53 or 54, wherein the solvent system used in (ii) is free of acidic and / or basic components, wherein preferably, the solvent system contains acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight.

[0320] 56. The method of any one of Examples 53 to 35, wherein the treated cellulose-based polymer fraction obtained in (ii) comprises one or more acidic and / or basic components with a total weight of 100 wt% based on the treated cellulose-based polymer fraction, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%.

[0321] 57. The method of any one of Examples 53 to 56, wherein the solvent system comprises γ-valerolactone, wherein the solvent system comprises γ-valerolactone based on a total weight of 100 wt% more preferably at least 50 wt%, more preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 99 wt%.

[0322] 58. The method of any one of Examples 53 to 57, wherein the solvent system comprises dimethyl sulfoxide, wherein the solvent system comprises 100% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, more preferably at least 99% by weight.

[0323] 59. The method of any one of Examples 53 to 58, wherein the solvent system comprises γ-valerolactone and dimethyl sulfoxide, wherein the solvent system comprises γ-valerolactone and dimethyl sulfoxide in a total weight of 100 wt% based on the total weight of the solvent system, more preferably at least 50 wt%, more preferably at least 60 wt%, more preferably at least 70 wt%, more preferably at least 80 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%, more preferably at least 99 wt%.

[0324] 60. A biogas, preferably a biogas containing methane, which is obtained or can be obtained by the method described in any one of Examples 1 to 52 or 53 to 59.

[0325] 61. Use of biogas as described in Example 60, preferably containing methane—preferably after purification and / or concentration—as a carbon source and / or hydrogen source.

[0326] 62. Use of biogas as described in Example 61, preferably biogas containing at least 40% methane, as an energy source, preferably a thermal energy source, for one or more of these steps (b) to (d).

[0327] 63. A polyester that is obtained or can be obtained by any one of the methods described in Examples 1 to 52 or 53 to 61.

[0328] 64. The use of polyester as described in Example 63 in textile applications, fiber applications, packaging applications, plastic applications, automotive applications, and electronic applications, preferably in the production of food packaging, beverage packaging, clothing, footwear, wires, and cables, wherein it is preferably used in textile applications, fiber applications, packaging applications, and plastic applications, and more preferably in the production of food packaging, beverage packaging, clothing, and footwear.

[0329] 65. A method for preparing a product, the method comprising:

[0330] (I) Provide the polyester as described in Example 63;

[0331] (II) Textiles, fibers, packaging, plastics, automotive parts, and electronic parts are made from the polyester provided in (I).

[0332] 66. The method as described in any one of Examples 1 to 52, wherein (b) comprises:

[0333] (b.1) Contact the polymer blend with the solvent system at a temperature T1 < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally the filler or a portion thereof, and a residue of the polymer blend depleted in the second polymer and / or colorant and optionally the filler or a portion thereof and containing the polyester, optionally the cellulose-based third polymer and optionally the filler or a portion thereof;

[0334] (b.2) Separating the solvent system obtained in (b.1) rich in dissolved second polymer and / or colorant, and optionally the filler or a portion thereof, from the residue—preferably by a physical separation method, thereby obtaining a separated solvent system richer in dissolved second polymer and / or colorant, and optionally the filler or a portion thereof, compared to the solvent system provided in (a); and

[0335] (b.3) Separate the second polymer from the solvent system to obtain a separated fraction containing the second polymer.

[0336] 67. A method, preferably as described in any one of Examples 1 to 52 or 53 to 64, comprising the following additional steps:

[0337] - Convert the second polymer and / or the re-acquired polyester.

[0338] To obtain one or more monomers, polymers, or polymer products.

[0339] 68. The method as described in Example 67,

[0340] The monomer is a diol or polyol, preferably butanediol; an aldehyde, preferably formaldehyde; a diisocyanate or polyisocyanate, preferably methylene diphenyl diisocyanate (MDI), polymeric methylene diphenyl diisocyanate (pMDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI); an amide, preferably caprolactam; an olefin, preferably styrene, ethylene and norbornene; an alkyne; a (di) ester, preferably methyl methacrylate; a monoacid or diacid, preferably adipic acid or terephthalic acid; a diamine, preferably hexamethylenediamine or nonadiamine; or a sulfone, preferably 4,4'-dichlorodiphenyl sulfone.

[0341] 69. The method as described in Examples 67 or 68,

[0342] The polymer and / or the polymer product contains polyamide (PA), preferably PA 6 or PA 66; a polyisocyanate addition polymer, preferably polyurethane (PU), thermoplastic polyurethane (TPU), polyurea or polyisocyanurate (PIR); low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrene (PS), polyacrylonitrile butadiene styrene (ABS), polystyrene acrylonitrile (SAN), polyacrylate styrene acrylonitrile (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene) -Isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate (PBAT), polyester (PES), polyethersulfone (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulfone (PSU), polyphenylene sulfone (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene ether) (PPO), poly(p-phenylene ether) (PPE); or copolymers or mixtures thereof.

[0343] 70. The method as described in any one of Examples 67 to 69,

[0344] The polymer and / or the polymer product is one or more of the following:

[0345] - Automotive parts; preferably cylinder head covers, engine hoods, turbocharger housings, turbocharger baffles, intake pipes, intake manifolds, connectors, gears, fan wheels, coolant tanks, housings, heat exchanger housings, coolant coolers, turbocharger coolers, thermostats, water pumps, radiators, fasteners, battery system components for electric vehicles, dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C, or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper protective housings, decorative grilles, covers, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushioning pads or coatings;

[0346] - Fabric; preferably shirts, trousers, sweaters, boots, shoes, shoe soles, bodysuits or jackets;

[0347] - Electrical components; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foil, wire, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, spools, lamps, diodes, LEDs, transistors, connectors, voltage regulators, integrated circuits (ICs), processors, controllers, memory, sensors, microswitches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, gaskets, bolts, strips, slide-in guides, screws, nuts, membrane hinges, spring hooks (clamp-in) or spring tongues;

[0348] - Consumer goods, agricultural products, or pharmaceutical products; preferably tennis strings, climbing ropes, bristles, brushes, artificial turf, 3D printed filaments, lawnmowers, zippers, hook and loop fasteners, paper machine netting, extrusion coatings, fishing lines, fishing nets, offshore lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyors, sliding bearings, rollers, wheels, gears, ring gears, screws and spring dampers, hoses, pipes, cable sheaths, sockets, switches, cable ties, fan wheels, carpets, cosmetic boxes or bottles, mattresses, cushioning pads, insulating materials, detergents, dishwasher detergent blocks or powders, shampoos, shower gels, bath gels, soaps, fertilizers, fungicides, or pest control agents;

[0349] - For packaging in the food industry, single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film, or laminated film are preferred; or

[0350] - Structural components, preferably rotor blades, insulating materials, frames, housings, walls, coatings, or partition walls.

[0351] 71. The method as described in any one of Examples 67 to 70,

[0352] Wherein, the content of the second polymer and / or the polyester in the monomer, polymer and / or polymer product is 1% by weight or more, preferably 2% by weight or more, more preferably 5% by weight or more, more preferably 15% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 60% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more, more preferably 95% by weight or more; and / or

[0353] Wherein, the content of the second polymer and / or the polyester in the monomer, polymer and / or polymer product is 100% by weight or less, preferably 95% by weight or less, more preferably 90% by weight or less, more preferably 50% by weight or less, more preferably 25% by weight or less, more preferably 10% by weight or less; and

[0354] Preferably, the content is determined based on an identity preservation and / or segregation and / or quality balance and / or ledger and declaration chain of custody model, preferably based on quality balance, preferred International Sustainability and Carbon Certification (ISCC) standards.

[0355] The invention is further illustrated by the following reference examples, comparative examples, and examples. Example

[0356] chemicals

[0357]

[0358] Hansen parameters from BIOVIA COSMOquick 2022

[0359] PET with Hansen parameters of δD = 18.2, δP = 6.4 and δH = 6.6 according to Hansen solubility parameters in practice (HSPiP) version 5.1.03 (2008).

[0360] Reference Example 1: Removal of colorant and / or second polymer (spandex)

[0361] The polymer material (in any processed form, such as textiles, sheets, etc.) is cut / shredded into fragments and placed in a reaction vessel (e.g., flask, tube, reaction vessel). GVL (in a mass-based ratio of polymer material to GVL of 1:1 to 1:100, preferably 1:1-1:20) is added, and the mixture is heated to a temperature in the range of 60°C to 160°C under an inert gas atmosphere using a suitable heating system (e.g., oil bath, heating block, small equipment container). After 0.5-8 h, the mixture is filtered, thereby obtaining GVL rich in colorant and / or spandex and polymer material fragments (optionally depleted in colorant and optionally at least partially depleted in filler), wherein the latter is washed with a small amount of GVL. To facilitate the removal of GVL and to accelerate the drying process of the polymer material fragments (optionally depleted in colorant and optionally at least partially depleted in filler), a small amount of acetone is optionally used in a second washing step. The resulting polymer material fragments are dried (e.g., in a vacuum chamber dryer).

[0362] Reference Example 2: Separation of PET and Cotton

[0363] A polymeric material containing PET and cotton (treated according to Reference Example 1 in the presence of spandex and / or colorant, or a fresh polymeric material containing PET and cotton) in shredded form is placed in a reaction vessel (e.g., a flask, tube, or reaction vessel). Degassed GVL (at a mass ratio of 1:1 to 100:1, preferably 1:1-10:1, GVL:polymeric material) is added, and the mixture is heated to 185°C at 1013 mbar under an inert gas atmosphere using a suitable heating system (e.g., an oil bath, heating block, or small equipment container) to obtain a mixture in which the PET is completely dissolved and the soluble portions of the filler (if present) are dissolved, but the solid particles remain in the mixture. After 5-60 min, the mixture is filtered (e.g., by heated pressure filtration) to obtain a filter cake containing undissolved polymeric material (the insoluble portions of cotton and filler (if present)) and a filtrate containing PET. Optionally, the filter cake is further washed with a small amount of hot GVL. As the filtrate begins to cool, PET precipitates. The precipitate is filtered, removing a portion of the filler (if present) that is soluble in GVL but does not precipitate during cooling, along with the filtrate. The precipitated PET is washed with a small amount of GVL. To facilitate GVL removal and expedite the drying process of the reclaimed color-poor PET powder, a small amount of acetone is optionally used in the second washing step. The filter cake (the residue containing a polymer blend of a third cellulose-based polymer) is also washed with a small amount of GVL. To facilitate GVL removal and expedite the drying process of the cotton scraps, a small amount of acetone is optionally used in the second washing step, and the filter cake is washed with water such that the resulting cotton scraps have an organic solvent content of less than 2% by weight (100% by weight) based on the total weight of the filter cake. The resulting cotton scraps are then dried (e.g., in a vacuum chamber dryer).

[0364] Reference Example 3: General Procedure for Solvent-Based Methods

[0365] Shredded cotton (textile sample) (125 g) is placed in a reaction vessel (e.g., flask, tube, container). A solvent is added (at a mass-based solvent:polymer ratio of 100:1 to 1:1, preferably 10:1-1:1), and the mixture is heated to a) the maximum of the corresponding boiling point of the solvent, or b) to 210°C, both under an inert gas atmosphere, using a suitable heating system (e.g., oil bath, heating block, small equipment container). After 1-60 min, the mixture is filtered, thereby obtaining a cotton fraction as a filter cake and a solvent as a filtrate. To facilitate solvent removal and accelerate the drying process, the solvent-treated cotton is washed with water. If the solvent used is poorly miscible in water, acetone can be used in the preceding washing step. The resulting cotton is dried (e.g., in air until constant weight).

[0366] Reference Example 4: Biochemical Methane Potential (BMP)

[0367] BMP testing was performed by mixing an inoculum (containing microorganisms) in a flask, with the corresponding sample serving as the substrate (chopped treated or untreated cotton or cotton derived from Reference Example 2). The mixture was then incubated at 37°C under anaerobic conditions. Biogas production over time was tracked, and methane content was analyzed by gas chromatography (GC). The method used was a pressure measurement method. This method relies on measuring the pressure generated in the flask due to biogas formation. The pressure in the flask was recorded, allowing for the calculation of the total volume of gas produced. By taking a gas sample and analyzing it in GC, the percentage of methane in the gas and thus the volume produced could be determined. The results are expressed as Nmlmethane / gVS (VS: volatile solids, in this case, the sample). The "N" in "Nml" represents standard and indicates that the volume is specified at a certain standard pressure and temperature of 1013 mbar and 0°C. The test was conducted in 500 ml flasks at 37°C for approximately 56 days.

[0368] The inoculum used was from the municipal wastewater treatment plant in Uppsala, Sweden. The organic loading rates used were 2 g VS test substrate / L and 6 g VS / L inoculum (= wastewater sludge).

[0369] BMP tests were performed in triplicate for each substrate, with the resulting methane values ​​indicated as the average of the three measurements. In addition to the BMP tests in triplicate for each substrate, positive controls and blanks containing microcrystalline cellulose were performed. The cellulose control assessed the microbial activity present in the inoculum, and a blank containing only the inoculum was included to subtract methane produced by the inoculum, so that the following... Figure 1The Nml methane / g VS results shown graphically and listed in Table 1 represent only methane derived from the substrate.

[0370] Comparative Example 1 (C1): Shredded cotton

[0371] Shredded cotton (textile sample) (125 g) was used in a fermentation process as described in Reference Example 4. The amount of methane obtained was... Figure 1 The figures are shown graphically and listed in Table 1.

[0372] Comparative Example 2 (C2): Treatment with enzymes

[0373] Shredded cotton (125 g) was used in a fermentation process as described in Reference Example 4, in which a cellulase mixture was additionally added. The amount of methane obtained was... Figure 1 The figures are shown graphically and listed in Table 1.

[0374] Comparative Example 3 (C3): Treatment with NaOH

[0375] Place shredded cotton (textile sample) (125 g) in a reaction vessel (e.g., flask, tube, container). Add 11% NaOH (at a mass ratio of NaOH:textile material of 10:1). Stir the mixture at 50°C for 1 hour. Afterward, decant the supernatant solution and add water to the residue (=cotton). Stir the mixture at room temperature (20°C–30°C) for 30 minutes and then filter. Optionally, repeat this step several times. The treated cotton is then dried (e.g., in air until constant weight).

[0376] The treated and dried cotton was then used in a fermentation process as described in Reference Example 4. The amount of methane obtained was... Figure 1 The figures are shown graphically and listed in Table 1.

[0377] Examples 1 to 4 (E1, E2, E3, E4): Solvent Treatment

[0378] According to Reference Example 2, cotton was obtained from the polymer material (textile sample) using DMSO (E1), Cyrene (E2), methyl phenylacetate (E3), or DMI (E4). The treated and dried cotton was then used in a fermentation process as described in Reference Example 4. The amount of methane obtained was... Figure 1 The figures are shown graphically and listed in Table 1.

[0379] Example 5 (E5): GVL Processing

[0380] Cotton was obtained from a polymer material (textile sample) according to Reference Example 2. The treated and dried cotton was then used in a fermentation process as described in Reference Example 4. The amount of methane obtained was... Figure 1 The figures are shown graphically and listed in Table 1.

[0381] Table 1

[0382] Methane production

[0383]

[0384] It can be seen that the cotton following the solvent-based method (E1-E5) yielded almost the same methane yield as when pretreated with NaOH. Furthermore, it therefore yielded more biomethane than cotton samples that were simply shredded and not treated with the solvent-based method. Attached Figure Description

[0385] Figure 1 The amounts of methane obtained from BMP in Comparative Examples 1 to 3 and Examples 1 to 5 are shown. References

[0386] -Anacleto, TM; Kozlowsky-Suzuki, B.; Wilson, AE; Enrich-Prast, A. Comprehensive Meta-Analysis of Pathways to Increase Biogas Production in theTextile Industry. Energies 2022, 15, 5574. https: / / doi.org / 10.3390 / en15155574

[0387] -Elnaz Hasanzadeh, Safoora Mirmohamadsadeghi, Keikhosro Karimi,Enhancing energy production from waste textile by hydrolysis of synthetic parts, Fuel, Volume 218, 2018, Pages 41-48, ISSN 0016-2361, https: / / doi.org / 10.1016 / j.fuel.2018.01.035.

[0388] -Kumar, P., Samuchiwal, S. & Malik, A. Anaerobic digestion of textileindustries wastes for biogas production. Biomass Conv. Bioref. 10, 715–724(2020). https: / / doi.org / 10.1007 / s13399-020-00601-8

[0389] -Xinyi Xiang, Xiaoguang Chen, Ruobin Dai, Ying Luo, Puyue Ma,Shengsheng Ni, Chengyu Ma, Anaerobic digestion of recalcitrant textile dyeingsludge with alternative pretreatment strategies, Bioresource Technology,Volume 222, 2016, Pages 252-260, ISSN 0960-8524, https: / / doi.org / 10.1016 / j.biortech.2016.09.098

[0390] -“Dyes and Pigments” Metin Açikyildiz, Kübra Günes, Ahmet GürsesSpringer, 2016 (ISBN: 10 : 3319338900)

[0391] -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)

[0392] -Chemistry and Technology of Natural and Synthetic Dyes and Pigments- Ashis Kumar Samanta, Nasser Awwad, IntechOpen, 2020 (ISBN: 9781789859980,9781789859973, 9781839687587)

[0393] -Encyclopedia of Color, Dyes, Pigments – Volume 1, Gerhard Pfaff, deGruyter, 2021 (ISBN: 311058588X)

[0394] -Heinrich Zollinger: Color Chemistry: Synthesis, Properties, and Applications of Organic Dyes and Pigments.3rd edition.WILEY-VCH Verlag, Weinheim 2003 (ISBN: 3-906390-23-3)

[0395] -Klaus Hunger (Ed.): Industrial Dyes: Chemistry, Properties, Applications. WILEY-VCH Verlag, Weinheim 2003 (ISBN: 3-662-01950-7)

[0396] -Hermann Rath: Textbook of Textile Chemistry, including Textile Chemical Technology. 2nd edition. Springer-Verlag, Berlin, Heidelberg 1963 (ISBN: 978-3-662-00065-6); Wilfried Kratzert, Rasmus Peichert

[0397] -Dyeing materials. Quelle & Meyer, Heidelberg 1981 (ISBN: 3-494-01021-8)

[0398] -Ullmann’s Encyclopedia of industrial chemistry, Wiley-VCH, 2000,sections “dyes and pigments” and “dyes, general survey” (ISBN:9783527303854)。

Claims

1. A method for producing biogas, the method comprising: Provides a polymer blend comprising (i) Polyester, and (ii) Optionally, one or more components selected from the group consisting of a second polymer, a colorant, and a filler; (iii) Cellulose-based third polymers; The optional second polymer (ii) and the cellulose-based third polymer (iii) are different from each other and different from the polyester of (i); The method includes: (a) Providing the polymer blend and providing a solvent system comprising γ-valerol or dimethyl sulfoxide or a mixture of γ-valerol and dimethyl sulfoxide, the solvent system comprising one or more acidic and / or basic components in an amount of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight. (b) Optionally, the polymer blend is contacted with the solvent system at a temperature T1 < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally the filler or a portion thereof, and a residue of the polymer blend depleted in the second polymer and / or colorant and optionally the filler or a portion thereof and containing the polyester, optionally the cellulose-based third polymer and optionally the filler or a portion thereof; (c) Contact the polymer blend provided in (a) or the residue of the polymer blend obtained in (b) with the solvent system at a temperature T2 > 170°C to obtain a solvent system rich in dissolved polyester and optionally containing the filler or a portion of the filler compared to the solvent system provided in (a), and a residue of the polymer blend that is polyester-poor and contains the cellulose-based third polymer and optionally the filler or a portion of the filler; (d) Optionally, the polyester is precipitated from the solvent system rich in dissolved polyester obtained in (c), thereby obtaining a solvent system containing precipitated polyester and dissolved polyester and optionally the filler or a portion thereof. (e) Prepare biogas from the residue of the polymer blend obtained in (c) and comprising the cellulose-based third polymer and optionally the filler or a portion thereof; Before (b), between (b) and (c), and before (c), the polymer blend provided in (a) or, optionally, the residue of the polymer blend obtained in (b) shall not come into contact with the acidic and / or alkaline components.

2. The method as described in claim 1, wherein, (c) The residue of the polymer blend obtained as a lean polyester and comprising the cellulose-based third polymer and optionally the filler or a portion thereof comprises one or more acidic and / or basic components in a total weight of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight; and / or wherein, The precipitated polyester obtained in (d) comprises one or more acidic and / or basic components based on a total weight of the precipitated polyester of 100 wt%, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%.

3. The method as described in claim 1 or 2, wherein, The cellulose-based third polymer is selected from the group consisting of: polymers based on natural cellulose, polymers based on synthetic cellulose, and mixtures of one or more polymers based on natural cellulose and one or more polymers based on synthetic cellulose, wherein the polymer based on natural cellulose is preferably selected from the group consisting of: cotton, cellulose, lignin, linseed, viscose fiber, and mixtures of two or more thereof, and wherein the polymer based on synthetic cellulose is preferably viscose fiber, wherein the cellulose-based polymer preferably contains at least cotton, and the total weight of the cellulose-based polymer is 100% by weight, more preferably at least 65% by weight, more preferably at least 70% by weight, more preferably at least 75% by weight, more preferably at least 80% by weight, more preferably at least 85% by weight, more preferably at least 90% by weight, more preferably at least 95% by weight, and more preferably the cellulose-based polymer is cotton.

4. The method according to any one of claims 1 to 3, wherein, According to (e), the preparation of biogas from the residue of the polymer blend includes microbial fermentation, more preferably anaerobic microbial fermentation.

5. The method according to any one of claims 1 to 4, wherein the method includes, after (e) (f) Methane is separated from the biogas obtained in (e) by one or more purification and / or concentration steps, thereby obtaining CH4 with a total volume of 100 vol-% based on the gas phase containing methane (CH4) and a purity of at least 85 vol-%, more preferably at least 90 vol-%, or even more preferably at least 95 vol-%.

6. The method according to any one of claims 1 to 5, wherein, The solvent system comprises 100% by weight, 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, and more preferably at least 99% by weight.

7. The method according to any one of claims 1 to 6, wherein, The polyester is based on 1,4-butanediol or 1,2-ethylenediol, more preferably the polyester according to (i) is selected from the group consisting of: polymers based on 1,4-butanediol and terephthalic acid (polybutylene terephthalate, PBT), polymers based on 1,2-ethylenediol and terephthalic acid (polyethylene terephthalate, PET), copolymers of 1,4-butanediol, adipic acid and terephthalic acid (polybutylene adipate terephthalate, PBAT), polymers of 1,2-ethylenediol and 2,5-furandicarboxylic acid (polyethylene furandicarboxylic acid, PEF), and mixtures of two or more of these (co)polymers, more preferably the polyester contains at least PET and / or PBT, more preferably the polyester is PET or PBT or a mixture of PET and PBT; and / or The second polymer is selected from the group consisting of polyurethane (PU), polyethylene glycol (PEG), polytetrahydrofuran (pTHF), mixtures of these polymers and copolymers of these polymers, wherein the second polymer is more preferably PU or a copolymer of PU and PEG and / or pTHF, and more preferably spandex (a copolymer of PU and PEG or PU and pTHF). and / or The polymer blend further comprises a fourth polymer (iv), which is different from the third cellulose-based polymer of the polyester (ii), (iii) and the second polymer of (ii), wherein the fourth polymer is selected from polypropylene (PP), polyethylene (PE), polyamide (PA), and mixtures of two or more thereof.

8. A method for preparing biogas from a cellulose-based polymer separated from a polymer blend, the method comprising: (i) Separating the cellulose-based polymer from a polymer blend comprising a cellulose-based polymer and at least one other polymer different from the cellulose-based polymer, thereby obtaining a separated cellulose-based polymer fraction; (ii) The cellulose-based polymer fraction obtained in (i) is treated with a solvent system comprising γ-valerolactone or dimethyl sulfoxide or a mixture of γ-valerolactone and dimethyl sulfoxide to obtain a treated cellulose-based polymer fraction, wherein the solvent system comprises one or more acidic and / or basic components in a total weight of 100% by weight, less than 10% by weight, preferably less than 8% by weight, more preferably less than 6% by weight, more preferably less than 5% by weight, more preferably less than 4% by weight, more preferably less than 3% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight. (iii) Biogas is prepared from the treated cellulose-based polymer fraction obtained in (ii); The polymer blend or the separated cellulose-based polymer fraction is not brought into contact with the acidic and / or alkaline components before, during, or between steps (i) and (ii).

9. The method of claim 8, wherein, (ii) The treated cellulose-based polymer fraction obtained comprises one or more acidic and / or basic components with a total weight of 100 wt%, less than 10 wt%, preferably less than 8 wt%, more preferably less than 6 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%.

10. A biogas, preferably a biogas containing methane, which is obtained or can be obtained by the method of any one of claims 1 to 7, 8 or 9.

11. The use of biogas as claimed in claim 10, preferably containing methane—preferably after purification and / or concentration—as a carbon source and / or hydrogen source; preferably containing at least 40 vol% methane as an energy source, preferably a thermal source, for one or more of these steps (b) to (d).

12. A polyester that is obtained or can be obtained by the method of any one of claims 1 to 7, 8 or 9.

13. The polyester of claim 12 is used in textile applications, fiber applications, packaging applications, plastic applications, automotive applications, and electronic applications, preferably in the production of food packaging, beverage packaging, clothing, footwear, wires, and cables, wherein it is preferably used in textile applications, fiber applications, packaging applications, and plastic applications, and more preferably in the production of food packaging, beverage packaging, clothing, and footwear.

14. A method for preparing a product, the method comprising: (I) Providing the polyester as described in claim 12; (II) Textiles, fibers, packaging, plastics, automotive parts, and electronic parts are made from the polyester provided in (I).

15. The method according to any one of claims 1 to 7, wherein, (b) Includes: (b.1) The polymer blend is contacted with the solvent system at a temperature T1 of < 170°C to obtain a solvent system rich in dissolved second polymer and / or colorant and optionally the filler or a portion thereof, and a residue of the polymer blend depleted in the second polymer and / or colorant and optionally the filler or a portion thereof and containing the polyester, the cellulose-based third polymer and optionally the filler or a portion thereof; (b.2) Separating the solvent system obtained in (b.1) rich in dissolved second polymer and / or colorant, and optionally the filler or a portion thereof, from the residue—preferably by a physical separation method, thereby obtaining a separated solvent system richer in dissolved second polymer and / or colorant, and optionally the filler or a portion thereof, compared to the solvent system provided in (a); and (b.3) Separate the second polymer from the solvent system to obtain a separated fraction containing the second polymer.

16. The method of any one of claims 1 to 7 or 15, wherein the method comprises the following additional steps: - Convert the second polymer and / or the re-acquired polyester. To obtain one or more monomers, polymers, or polymer products; Preferably, the monomer is a diol or polyol, preferably butanediol; an aldehyde, preferably formaldehyde; a diisocyanate or polyisocyanate, preferably methylene diphenyl diisocyanate (MDI), polymeric methylene diphenyl diisocyanate (pMDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI); an amide, preferably caprolactam; an olefin, preferably styrene, ethylene and norbornene; an alkyne; a (di) ester, preferably methyl methacrylate; a monoacid or diacid, preferably adipic acid or terephthalic acid; a diamine, preferably hexamethylenediamine or nonanediamine; or a sulfone, preferably 4,4'-dichlorodiphenyl sulfone; and / or Preferably, the polymer is and / or the polymer product comprises polyamide (PA), preferably PA 6 or PA 66; a polyisocyanate addition polymer, preferably polyurethane (PU), thermoplastic polyurethane (TPU), polyurea or polyisocyanurate (PIR); low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrene (PS), polyacrylonitrile butadiene styrene (ABS), polystyrene acrylonitrile (SAN), polyacrylate styrene acrylonitrile polyacrylate (ASA), polytetrafluoroethylene (PTFE), poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), polybutadiene (BR, PBD), poly(cis-1,4-isoprene), poly(trans-1,4-isoprene) -Isoprene), polyoxymethylene (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene adipate (PBAT), polyester (PES), polyethersulfone (PESU), polyhydroxyalkanoate (PHA), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polyhydroxyoctanoate (PHO), polylactic acid (PLA), polysulfone (PSU), polyphenylene sulfone (PPSU), polycarbonate (PC), polyetheretherketone (PEEK), poly(p-phenylene ether) (PPO), poly(p-phenylene ether) (PPE); or copolymers or mixtures thereof; and / or Preferably, the polymer and / or the polymer product is one or more of the following: - Automotive parts; preferably cylinder head covers, engine hoods, turbocharger housings, turbocharger baffles, intake pipes, intake manifolds, connectors, gears, fan wheels, coolant tanks, housings, heat exchanger housings, coolant coolers, turbocharger coolers, thermostats, water pumps, radiators, fasteners, battery system components for electric vehicles, dashboards, steering column switches, seats, headrests, center consoles, transmission components, door modules, A, B, C, or D pillar covers, spoilers, door handles, exterior mirrors, windshield wipers, windshield wiper protective housings, decorative grilles, covers, roof rails, window frames, sunroof frames, antenna panels, headlights and taillights, engine hoods, cylinder head covers, intake manifolds, airbags, cushioning pads or coatings; - Fabric; preferably shirts, trousers, sweaters, boots, shoes, shoe soles, bodysuits or jackets; - Electrical components; preferably electrical or electronic passive or active components, circuit boards, printed circuit boards, housing components, foil, wire, switches, plugs, sockets, distributors, relays, resistors, capacitors, inductors, spools, lamps, diodes, LEDs, transistors, connectors, voltage regulators, integrated circuits (ICs), processors, controllers, memory, sensors, microswitches, micro buttons, semiconductors, reflector housings for light-emitting diodes (LEDs), fasteners, gaskets, bolts, strips, slide-in guides, screws, nuts, membrane hinges, spring hooks (clamp-in) or spring tongues; - Consumer goods, agricultural products, or pharmaceutical products; preferably tennis strings, climbing ropes, bristles, brushes, artificial turf, 3D printed filaments, lawnmowers, zippers, hook and loop fasteners, paper machine netting, extrusion coatings, fishing lines, fishing nets, offshore lines and ropes, vials, syringes, ampoules, bottles, sliding elements, spindle nuts, chain conveyors, sliding bearings, rollers, wheels, gears, ring gears, screws and spring dampers, hoses, pipes, cable sheaths, sockets, switches, cable ties, fan wheels, carpets, cosmetic boxes or bottles, mattresses, cushioning pads, insulating materials, detergents, dishwasher detergent blocks or powders, shampoos, shower gels, bath gels, soaps, fertilizers, fungicides, or pest control agents; - For packaging in the food industry, single-layer or multi-layer blown film, cast film (single-layer or multi-layer), biaxial stretch film, or laminated film are preferred; or - Structural components, preferably rotor blades, insulating materials, frames, housings, walls, coatings, or partition walls.

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