Recycling of PU-soft foams with grafted polyol contents

Abstract

The present invention relates to a process for recycling waste containing a grafted polyol-containing polyurethane, the process comprising the steps of: providing a composition comprising a comminuted polyurethane material, the comminuted polyurethane material comprising a grafted polyol; depolymerizing the comminuted polyurethane by hydrolysis, aqueous alcoholysis, aqueous ammonolysis or aqueous aminolysis, wherein the content of water in the reaction mixture is in the range of 3.5 to 15 wt.-% based on the reaction mixture; adjusting the water content to achieve phase separation; the amine component and the polyol component are separated into an amine-rich phase and an amine-lean phase. Furthermore, the invention relates to the polyol and isocyanate compositions obtained in said method and to the use of the polyol and isocyanate compositions for producing polyurethanes.

Description

[0001] The present invention relates to a process for recycling waste containing polyurethane with grafted polyols, comprising the steps of: providing a composition comprising a comminuted polyurethane material, the comminuted polyurethane material comprising grafted polyols; depolymerizing the comminuted polyurethane by hydrolysis, hydroglycolysis, hydroammonolysis or hydroaminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture; adjusting the water content to achieve phase separation; separating the amine component and the polyol component into an amine-rich phase and an amine-lean phase. Furthermore, the present invention relates to a polyol composition and an isocyanate composition obtained in said process and the use of the polyol composition and the isocyanate composition for the preparation of polyurethanes.

[0002] The recycling of waste streams represents a key component to achieve higher sustainability of existing value chains. In the material cycle of plastics, re-monomerization is one of the recycling technologies with the highest recyclability. In the field of plastics, polyurethane plastics is one of the most voluminous classes. Polyurethanes are prepared in form of an addition polymerization of at least one polyol with at least one polyisocyanate.

[0003] One re-monomerization strategy discussed in the literature and patents is hydroglycolysis, where initially formed urethanes are subsequently hydrolyzed to the corresponding amines with release of carbon dioxide. The process can be carried out in one or two steps. Various basic amines, alkali and alkaline earth metal hydroxides are disclosed in the literature as catalysts for hydroglycolysis.

[0004] CN 106700126 discloses a method for autocatalytic degradation and recycling of polyurethane foams. The method is suitable for recycling polyurethane waste.

[0005] US 20010027246 discloses a method for recovering decomposition products from polyurethane, comprising the steps of: thermally decomposing the polyurethane in the presence of a polyamine compound at a temperature of 120°C to 250°C into a liquid containing a polyol and a urea compound soluble in the polyol and a solid containing a urea compound insoluble in the liquid; removing the solid; hydrolyzing the residue with water at an elevated temperature and pressure of 200°C to 320°C; and recovering the resulting polyamine and / or polyol.

[0006] EP 1 142 945 A2 relates to a method for chemically decomposing chips produced in the molding or manufacturing of articles of polyurethane resin and waste of such resin articles for industrially advantageously recovering a polyamine compound and a polyol compound usable as a raw material for a polyurethane resin.

[0007] According to CN 1275587, polyurethane waste is decomposed in an aqueous solution and the catalyst is separated in the aqueous phase for recycling. The decomposition products polyether and toluene diamine can be separated in water.

[0008] Polyurethane materials, in particular foams, such as flexible foams used in particular in mattresses and furniture, can contain grafted polyols, which are typically SAN-particles grafted with polyether alcohols. These grafted polyols hinder the phase separation during recycling and significantly slow down any filtration process, which makes downstream processing technically very difficult. The recyclability of the catalyst is not mentioned anymore.

[0009] It is therefore an object to provide a process for recycling a waste stream containing polyurethane, which also comprises polyurethane containing grafted polyols, in such a way that the maximum yield of polyols and amine monomers can be achieved, while simplifying the technical work-up and ensuring the recyclability of the catalyst.

[0010] According to the present application, this object is solved by a process for recycling a waste containing polyurethane containing grafted polyols, comprising the steps of

[0011] a) providing a composition comprising a comminuted polyurethane material, which comprises grafted polyols;

[0012] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alkylation, hydrolysis-amination or hydrolysis-amination, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture;

[0013] c) optionally adjusting the water content to achieve a phase separation;

[0014] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase.

[0015] It was surprisingly found that the use of the specific sequence of reaction steps according to the present application leads to the cleavage of the stabilizer polyol, i.e. the macromonomer in the synthesis of the grafted polyol, and the adjustment of water leads to a phase separation. Thus, the process allows to re-monomerize the polyurethane containing grafted polyols in an efficient way.

[0016] It has been found that the process is particularly suitable for the recycling and re-monomerization of polyurethane foams. Thus, according to the present application, the polyurethane material is preferably a polyurethane foam, in particular a flexible polyurethane foam.

[0017] In the context of the present invention, the polyurethane material comprising grafted polyols is to be understood as a polyurethane material comprising an amount of grafted polyols which is typical for polyurethane materials, preferably in the range of 2.5 to 30 % by weight of the polyurethane material, in particular in the range of 5 to 30 % by weight of the polyurethane material, more preferably in the range of 7.5 to 30 % by weight of the polyurethane material.

[0018] The process according to the present invention comprises the steps a), b), optionally c), and d), but can comprise further steps. It has been found that the specific order of process steps according to the present invention allows for a simple way of recovering polyols and isocyanates from a polyurethane material comprising grafted polyols in high quality.

[0019] According to the process of the present invention, both starting material components can be recovered from the polyurethane. The polyurethane components are recovered directly (e.g. polyols) or obtained as valuable synthetic building blocks (e.g. di- or polyfunctional aromatic amines which can be easily converted into polyisocyanates).

[0020] According to step a), a composition comprising a comminuted polyurethane material comprising grafted polyols is provided.

[0021] The term "grafted polyol" used according to the present invention, also commonly referred to as polymeric polyol, means a dispersion of polymers (mainly acrylonitrile-styrene copolymers stabilized by copolymerization of macromonomers) in a polyether polyol matrix. Grafted polyols used for the preparation of polyurethane materials typically have a hydroxyl number in the range of 15 to 120 mg KOH / g. They can be present in the polyurethane material in amounts of up to 25 wt. %.

[0022] In the context of the present invention, "comminuted polyurethane material" means that the material is obtained from the material and the comminuted polyurethane is used for example in the form of a shredded form, a granulate form, a flake form, an agglomerate form, or a powder form. The polyurethane material can be comminuted by conventional methods, for example by shredding, for example at room temperature, in a rotation mill or a rotary mill to a particle size of typically less than 500 mm, for example to a particle size in the range of 10 to 500 mm, or for example by known cold grinding methods.

[0023] The properties of the polyurethane material can vary within a wide range, for example the content of graft polyol present in the polyurethane material can vary. In principle, polyurethane materials without graft polyol can also be used according to the present application. According to a further embodiment, the present application also relates to a process as disclosed above, wherein the comminuted polyurethane material comprises a mixture of different polyurethane materials, which can for example vary in the content of graft polyol present.

[0024] The polyurethane material used in the present application is preferably obtained from articles produced from polyurethane material or polyurethane material waste from the production process after the time for its manufacturing purposes. These articles can be subjected to a sorting step and / or to mechanical comminution before being subjected to the process of the present application. That is, the articles are further sorted and brought to the appropriate size, for example by shredding, sieving or separation by density rate, i.e. by air, liquid or magnetism. Optionally, the pieces can then undergo a process of impurities elimination, for example paper labels. Suitable methods are in principle known to the person skilled in the art.

[0025] Furthermore, the process can comprise a sorting step based on optical methods, for example based on NIR spectroscopy. The graft polyol content of the polyurethane material can be determined in the process, for example using optical method based sorting. Preferably, the process can also comprise a step of adjusting the graft polyol content of the mixture within a predetermined range.

[0026] In the present context, the term "polyurethane material waste" includes scrap polyurethane material and production rejects of PU material or waste generated by further processing of PU material. In this context, the term "used polyurethane material" denotes an article produced from polyurethane material that has already been used for its manufacturing purposes. "Production rejects of polyurethane material" denotes polyurethane material waste generated in the production process of PU material.

[0027] Typically, polyurethane materials are produced by reaction between a polyisocyanate component and a polyol component. Typically, additional materials, in particular additives, such as flame retardants (e.g. phosphorous based), polymerization catalysts (e.g. tertiary amines), fillers and surfactants (e.g. siloxanes) can be added during the production of the polymer. In order to prepare a polyurethane material containing graft polyol, a graft polyol is used in the polyol component.

[0028] The properties of the polyurethane material are influenced by the chemical nature of the polyisocyanate and polyol components used and the formulation applied in the polymerization. For example, the starting materials can influence the crosslinking density of the polymer in the three-dimensional network. Block soft polyurethane foams are typically obtained from TDI and polyether polyols having an OH number of 35 to 70 mgKOH / g and a functionality of 2.5-3.5, resulting in a medium crosslinked network.

[0029] In industry and thus in large amounts, especially toluene 2,4 and 2,6-diisocyanate (TDI) or methylene di(phenyl isocyanate) (MDI) or polymeric forms thereof or as polyisocyanate component for the production of PU flexible foams and PU rigid foams. For representative compositions of these PU foams, see, for example, US 9,023,907 B2, WO 2015 / 121057 and WO 2013 / 139781.

[0030] The organic polyisocyanates which can be used for the preparation of polyurethanes, preferably for flexible foams, are any known organic polyisocyanates, preferably aromatic polyfunctional isocyanates. In the context of the present invention, the term polyisocyanate encompasses isocyanates having 2 or more isocyanate groups, i.e. also diisocyanates.

[0031] Suitable polyisocyanate components for the production of polyurethanes or polyisocyanurates include any of the polyisocyanates known for the production of polyurethanes or polyisocyanurates. These include aliphatic, cycloaliphatic and aromatic di- or polyfunctional isocyanates known from the prior art, and also any desired mixtures thereof. Examples are diphenylmethane 2,2'-, 2,4'- and 4,4'-diisocyanate, mixtures of monomeric diphenylmethane diisocyanates with diphenylmethane diisocyanate homologues having a greater number of rings (polymeric MDI), isophorone diisocyanate (IPDI) and oligomers thereof, toluene 2,4- and 2,6-diisocyanate (TDI) and mixtures of these, tetramethylene diisocyanate and oligomers thereof, hexamethylene diisocyanate (HDI) and oligomers thereof, naphthylene diisocyanate (NDI), and mixtures thereof. Preferably, toluene 2,4- and 2,6-diisocyanate (TDI) is used.

[0032] Preferably, toluene 2,4- and / or 2,6-diisocyanate (TDI) or mixtures thereof, monomeric diphenylmethane diisocyanates, and / or diphenylmethane diisocyanate homologues having a greater number of rings (polymeric MDI), and mixtures of these are used. Other possible isocyanates are mentioned, for example, in "Kunststoffhandbuch [Plasticshandbook] [Plastics Handbook], Volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, Chapters 3.2 and 3.3.2.

[0033] The organic and polyisocyanates can be used individually or in the form of mixtures.

[0034] The common polyols used in large amounts are, for example, selected from the group consisting of polyether polyols, polyester polyols, polyether ester polyols and mixtures thereof, preferably polyether polyols.

[0035] Polyetherols are produced, for example, from epoxides, such as propylene oxide and / or ethylene oxide, or from tetrahydrofuran with starting compounds which exhibit hydrogen activity, such as aliphatic alcohols, phenols, amines, carboxylic acids, water, or compounds based on natural substances, such as glycerol, sucrose, sorbitol or mannitol, in the presence of a catalyst. Mention can be made here of basic catalysts and double metal cyanide catalysts, as described, for example, in WO 2006 / 034800, EP 0090444, or WO 2005 / 090440.

[0036] Polyesterols are produced, for example, from aliphatic or aromatic dicarboxylic acids and polyols, polythioether polyols, polyesteramides, hydroxylated polyacetals, and / or hydroxylated aliphatic polycarbonates, preferably in the presence of an esterification catalyst. Other possible polyols are mentioned, for example, in "Kunststoffhandbuch [Plastics handbook] [Plastics handbook], Volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, Chapter 3.1.

[0037] According to step b), the comminuted polyurethane provided in step a) is depolymerized by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the content of water in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture.

[0038] Preferably, the depolymerization is achieved by hydrolysis, hydrolysis-alcoholysis, hydrolysis-ammonolysis or hydrolysis-aminolysis according to the present application. The process of the present application can optionally comprise an alcoholysis, ammonolysis or aminolysis step in combination with the hydrolysis step, wherein the polyurethane material is contacted with a suitable substance containing OH or NH groups substances. During alcoholysis, ammonolysis or aminolysis of the polyurethane material in the presence of water, a mixture containing polyol substances and amine substances is formed. According to a preferred aspect of the present application, the polyurethane material is contacted with an alcoholysis substance and water. Hydrolysis of the polyurethane material occurs due to the addition of water or due to the presence of water in the original polyurethane material. According to the present application, the hydrolysis step can be carried out separately or can be combined with the alcoholysis, ammonolysis or aminolysis step. Typically, the amines corresponding to the isocyanate components used in the PU material are obtained by applying a depolymerization process comprising a hydrolysis step, optionally together with or after applying, for example, alcoholysis, ammonolysis, aminolysis.

[0039] According to a further embodiment, the present application relates to the process as disclosed above, wherein the depolymerization according to step b) is obtained by a process comprising a hydrolysis step together with the application of alcoholysis, ammonolysis or aminolysis.

[0040] In case the polyurethane material already contains water, it can not be necessary to add water to adjust the water content of the water in the reaction mixture to be in the range of 3.5 to 15 wt.-% based on the reaction mixture. In case the original water content of the polyurethane material is not in the described range, a suitable amount of water can be added. The water content in the reaction mixture is preferably in the range of 4 to 15 wt.-% based on the reaction mixture.

[0041] For an optimized raw material release yield, preferably step b) is carried out in the presence of a catalyst, wherein preferably the catalyst is selected from the group consisting of alkali metal hydroxides; alkaline earth metal hydroxides; alkali metal carboxylates, in particular acetates; alkaline earth metal carboxylates, in particular acetates; Lewis acids, in particular dibutyltin dilaurate; organic amines, in particular imidazole or diethanolamine, or aromatic amines, such as aniline, toluenediamine or methylenebis(phenylamine); organometallic compounds, in particular rare earth metal catalysts, for example titanium tert-butoxide; or tin compounds, such as tin octoate. As alkali metal hydroxides, in particular the use of potassium hydroxide (KOH), sodium hydroxide (NaOH), or cesium hydroxide (CsOH) is preferred. Suitable catalysts are for example disclosed in WO 2022 / 171586 or US 2022 / 0251328.

[0042] According to a preferred embodiment, the catalyst, for example potassium hydroxide or sodium hydroxide, is used in an amount of about 0.2 wt.-% or more and / or about 5 wt.-% or less.

[0043] In the context of the present application, preferably the corresponding amine of the isocyanate used in the process or present in one of the components can be used as catalyst. According to a further preferred embodiment, the catalyst, for example 2,4-toluenediamine and / or 2,6-toluenediamine (TDA) or mixtures thereof, is used in an amount of about 1 wt.-% or more and / or about 20 wt.-% or less.

[0044] As alcoholysis substance, preferably an alcohol is used. For example, the alcoholysis substance comprises or consists of one or more of the following: methanol, ethanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methylene glycol, triethylene glycol, glycerol, 2-methyl-1,3-propanediol and mixtures of two or more thereof. As ammonolysis substance, preferably an amine is used, such as ethylamine, diaminooethane or diaminopropane.

[0045] For alcoholysis or aminolysis of polyurethane materials, preferably about 0.25 parts by weight or more and / or about 5 parts by weight or less of alcoholysis substances or aminolysis substances per part by weight of polyurethane material are used. Suitable methods are in principle known to the person skilled in the art.

[0046] Preferably, both starting material components can be recovered from the polyurethane. Typically, the isocyanate component or isocyanate precursors like amines, carbamates or ureas are obtained and can be separated, but also the polyol component can be separated. Usually, the depolymerization yields a mixture of components which can be separated using suitable separation techniques. The process of the present application can thus also comprise a further separation step.

[0047] After the depolymerization, the process of the present application typically yields a polyamine comprising amino groups attached to carbon atoms which were bound in the initial polyisocyanate isocyanate groups, such as for example toluenediamine (TDA), in particular 2,4-toluenediamine or 2,6-toluenediamine, methylenediphenyl diamine (MDA), oligomeric and polymeric methylenphenylene amines, hexamethylenediamine (HDA), or naphthalene diamine (NDA). The polyols which are commonly used as described above can preferably also be re-isolated. Thus, the process preferably further yields polyether polyols having a molecular weight in the range of 2000 to 5000 g / mol, in particular in the range of 2500 to 4000 g / mol and an OH number in the range of 25 to 800 mgKOH / g, in particular 25 to 500 mgKOH / g, preferably 25 to 70 mgKOH / g, more preferably 30 to 70 mgKOH / g. Preferably, the polyol substance comprises or consists of one or more polyols having a molecular weight of about 2500 to about 4000 g / mol, using a nominal functionality in the range of 1 to 6, preferably between 1 to 4.5, in particular in the range of 1 to 4.1, more preferably in the range of 1 to 3.9, most preferably in the range of 1.1 to 3.5.

[0048] According to the present application, the depolymerization is preferably achieved using suitable temperatures and adjusting the temperature and the water content. Typically, the alcohol, in particular ethylene glycol, and the catalyst, for example the isocyanate to amine, are charged into the reactor and then the material is added at high temperatures in the range of 140 °C to 250 °C.

[0049] Typically, water is then added, resulting in a temperature decrease at atmospheric pressure without pressure build-up. Typically, the depolymerization starts at a temperature in the range of 100 °C to 150 °C with cleavage of the grafted polyol. The water content and / or the temperature can be adjusted to complete the depolymerization. For example, the reaction temperature can be increased by adjusting the water content, in particular by decreasing the water content. According to a further embodiment, the reaction can also be carried out in a pressure reactor. In this case, according to the present application, the reaction can take place at higher temperatures at high water content. After the depolymerization, typically a mixture of reaction products is obtained.

[0050] The process of the present application optionally comprises step c). According to step c) of the process according to the present application, the water content is adjusted to achieve a phase separation. The water content can be adjusted by decreasing the water content. Preferably, the water content is adjusted to an amount of 0.1 to 1 wt.-% based on the weight of the reaction mixture. It can be beneficial if the excess water is removed from the mixture before allowing the mixture to settle, preferably by evaporating the excess water. In particular, to evaporate the excess water, the mixture is heated and / or a vacuum is applied to it. For example, the excess water is removed by using flash evaporation or applying a vacuum to the already heated mixture. For example, the water removal step can be carried out for about 120 minutes or less, in particular for about 90 minutes or less, for example for about 75 minutes or less, for example for about 60 minutes or less. Preferably, the water removal step is carried out for about 10 minutes or more, in particular for about 30 minutes or more, for example for about 40 minutes or more.

[0051] According to a further embodiment, the present application also relates to a process as disclosed above, wherein step c) is carried out and the water content is adjusted in the range of 0.1 to 1 wt.-% based on the reaction mixture.

[0052] The components obtained in the depolymerization can be separated. In the context of the present application, also by-products (such as, for example, carbon dioxide) or waste material can be separated before separating the amine component and the polyol component.

[0053] Preferably, the process further comprises allowing the mixture to settle, wherein one or more phases are formed. According to the present application, one or more phases can be formed and the components of the mixture can be separated by suitable separation steps. According to the present application, the mixture can be extracted, for example, by a water-free organic solvent immiscible or partially miscible with water.

[0054] According to step d) of the process according to the present application, the amine component and the polyol component obtained in step b) or step c) are separated into an amine-rich phase and an amine-lean phase.

[0055] The work-up of the depolymerization product, in particular the separation of polyamines and polyols, can be effected as appropriate, for example by extraction work-up, precipitation of the amine components as hydrochlorides, chromatography or distillation under reduced pressure. Preferably, the work-up comprises several steps.

[0056] According to a preferred embodiment, the phase separation is carried out after the mixture has been allowed to stand. Preferably, the phase separation is carried out in a phase separation apparatus. For improved phase separation, it can be beneficial to remove water contained in the mixture, for example by flashing. The removal of water can also be accomplished by applying a vacuum to the mixture or simply distilling the mixture at atmospheric pressure. In principle, the phase separation can also be improved by the addition of salts or by using specific internals in the phase separation apparatus. Suitable methods are in principle known to the person skilled in the art.

[0057] According to one aspect of the present application, solids can be removed from the mixture before or after the mixture has been allowed to stand, preferably by one or more of the following: filtration, centrifugation, decanting, evaporation of the phase in one or more evaporators, contacting the phase with ion exchange material; contacting the phase with one or more adsorbents.

[0058] Suitable methods for removing particulate solids are in principle known to the person skilled in the art. For example, a filter unit or a centrifuge can be used.

[0059] In the alternative or additionally, centrifugation is the preferred solid-liquid separation method.

[0060] According to the present application, the method can comprise a further separation step, purification step or sorting step. For example, components such as flame retardants can be removed from the comminuted polyurethane or polyisocyanurate material by suitable methods such as, for example, extraction. Other extractable components are other and sometimes even solid additives. Flame retardants can also be purified and reused. Furthermore, the comminuted polyurethane can be sorted, for example by the chemical nature of the components used or by the content of additives. The sorting can be carried out, for example, by using optical methods such as, for example, NIR spectroscopy.

[0061] According to a further embodiment, the present application also relates to the method as disclosed above, wherein the method further comprises the step a1) and / or the step a2)

[0062] a1) sorting the materials using optical methods, in particular NIR spectroscopy;

[0063] a2) at least partially extracting flame retardants from the comminuted polyurethane or polyisocyanurate material.

[0064] Suitable conditions for step a1) are disclosed, for example, in EP 22205386.0.

[0065] Further separation steps can be performed according to the present application to isolate further by-products.

[0066] In a post-treatment by distillation, the compounds are separated according to their volatility, wherein the compounds with higher volatility are separated first. The additives used in the depolymerization, water or solvents can also be removed by distillation before further post-treatment of the polyol-polyamine mixture. In general, the "volatility" of a liquid can be described using its vapor pressure, wherein a high vapor pressure indicates a high volatility, and vice versa.

[0067] In case the polyamines are more volatile than the polyols, for example in case of TDA, monomeric MDA and NDA, the polyamines are recovered from the depolymerization product by distillation, preferably by distillation under reduced pressure. After distilling off the polyamines, the remaining distillation bottom contains the polyols.

[0068] Suitable conditions for distillation are in principle known to the person skilled in the art and are for example disclosed in EP 22178796.3 or EP 22178797.1.

[0069] According to one aspect of the present application, it can be beneficial if one or more adsorbents are added prior to the removal of the solids. For example, the one or more adsorbents can act as filtration aids.

[0070] According to one aspect of the present application, the mixture is contacted with one or more adsorbents prior to allowing the mixture to settle, wherein preferably the one or more adsorbents are selected from the group consisting of activated carbon, silicon dioxide, silicates, in particular alkali silicates and / or alkaline earth silicates (e.g. magnesium silicate), or a mixture of two or more thereof. It is particularly preferred to use silicates, for example magnesium silicate and / or sodium silicate, as adsorbents prior to phase separation.

[0071] According to one aspect of the present application, the phase enriched in polyol material is purified by performing a solid-liquid separation prior to purification, wherein the solid-liquid separation comprises one or more of the following: filtration, centrifugation, decanting.

[0072] Preferably, the post-treatment of the mixture leads to partial or essentially complete release and / or recovery of the alcoholysis or aminolysis material.

[0073] Alternatively, the polyol component can be recovered by extraction from the depolymerization mixture using a suitable extractant or a pair of extractants.

[0074] Further, in particular for the recovery of the polyol component, the method preferably comprises post-treatment of the phase enriched in polyol material by purifying the polyol material. The purification can comprise one or more of the following:

[0075] - filtration;

[0076] - centrifugation;

[0077] - decantation;

[0078] - extraction;

[0079] - distillation;

[0080] - complete or partial evaporation of the phases in one or more evaporators;

[0081] - contacting the phases with ion exchange material;

[0082] - contacting the phases with one or more adsorbents.

[0083] Preferably, the method further comprises post-treatment of the mixture by purifying the amine substance, for example comprising distillation, in order to purify the amine substance.

[0084] It will be understood that the separation and purification methods described above can be combined with any of the various embodiments of the inventive method described herein.

[0085] The method according to the present application comprises steps a), b), c) and d), but can also comprise additional steps. The method can for example comprise additional purification steps or heat treatment. According to a further embodiment, the present application also relates to a method as disclosed above, wherein the method comprises an additional purification step as disclosed above.

[0086] Suitable treatment steps are in principle known to the person skilled in the art. Suitable treatment and / or purification steps can be carried out between steps a) and b), or between steps b) and c) or between steps c) and d). It is also possible that step b) is carried out directly after step a) in the context of the present application. It is also possible that step c) is carried out directly after step b), or step d) is carried out directly after step c).

[0087] According to the present application, steps a) and b) can also be combined and carried out in the same apparatus. It is also possible that the composition provided in step a) can also comprise a solvent, for example a solvent which can be used in step b) of the method according to the present application.

[0088] After work-up, the phase enriched in polyol substances preferably has an acid value of 0.1 mg KOH / g or less. The acid number (corresponding to the acid value) is determined according to DIN EN ISO 4629-2 (with minor changes). Instead of toluene / ethanol 2:1, a mixture of isopropanol / water 1 : 1 is used as solvent mixture. As a further change, NaOH / KOH is dissolved in methanol instead of ethanol.

[0089] Preferably, the process further comprises work-up of the mixture by purification of the amine substances, for example comprising distillation, extraction, adsorption, precipitation or crystallization, in order to purify the amine substances.

[0090] It is understood that the separation process described above can be combined with any of the various embodiments of the inventive process described herein.

[0091] With the inventive process, about 90% or more, preferably about 97% or more, of the theoretically recoverable polyol substances from the polyurethane material can be liberated. Thus, the yield of liberated polyol substances or monomeric fragments of polyol substances is about 50% or more, preferably 60 wt.-% or more, in particular 75 wt.-% or more.

[0092] According to a further aspect, the present application also relates to a polyol composition obtained or obtainable according to the process as disclosed above. The obtained polyol composition typically further comprises polyol of the grafted polyol.

[0093] According to a further aspect, the present application also relates to the use of a polyol composition according to the present application or a polyol composition obtained or obtainable according to the process of the present application for the preparation of a polyurethane or a polyisocyanurate-containing polyurethane material.

[0094] The present application further relates to a process for the preparation of a polyurethane material by reacting a polyol substance obtained by the process according to the present application with an isocyanate substance, preferably an isocyanate substance obtained by the process of the present application.

[0095] According to a further embodiment, the present application relates to the use of a polyol composition according to the present application or a polyol composition obtained or obtainable according to the process as disclosed above for the preparation of a polyurethane or a polyisocyanurate.

[0096] The present application further relates to a process for the preparation of a polyurethane material by reacting a polyol substance obtained by the process according to the present application with an isocyanate substance. The polyol substance can also be used in a mixture comprising further polyols.

[0097] The produced polyurethane material can be used in any suitable polyurethane application, also in the production of thermoplastic polyurethanes, preferably in the same application. The polyurethane material can for example preferably be used in a mattress, a furniture part or a car seat, or also in an electrical or construction application, or in a car part (like a dashboard, steering wheel, bumper), in a consumer product (like a leisure shoe, sports shoe or safety shoe).

[0098] According to the present application, also the amine substance can be recovered. Thus, the present application also relates to a process for producing an isocyanate substance from the amine substance obtained by the process according to the present application. The advantages and / or features described in connection with the process for recovering the polyol also apply to the process for producing the isocyanate substance.

[0099] Preferably, the amine substance obtained from the recovery process is fed to a purification section of an amine production plant, to an amine storage tank or to an isocyanate production plant, for example to a phosgenation section of an isocyanate production plant. Preferably, the amine substance is phosgenated such that an isocyanate substance is formed. For example, TDA can be phosgenated to produce TDI, or MDA can be phosgenated to produce MDI. Also, pMDA can be phosgenated to produce pMDI, and NDA can be phosgenated to produce NDI. Suitable conditions for the phosgenation are in principle known to the person skilled in the art.

[0100] Thus, according to a further embodiment, the present application also relates to the process as disclosed above, wherein the process further comprises the step e)

[0101] e) converting the amine component to obtain an isocyanate composition.

[0102] In the context of the present application, the term "isocyanate composition" encompasses all isocyanates known to the person skilled in the art in connection with polyurethane chemistry, like in particular toluene diisocyanate (TDI; produced from toluene diamine (TDA)) or di- and polyisocyanates of the diphenylmethane series (MDI; produced from diamines and polyamines of the diphenylmethane series (MDA)). The expression "isocyanate composition" also encompasses embodiments in which two or more different isocyanates (for example a mixture of MDI and TDI) are used in the production of a polyurethane material. This also applies within one isocyanate class (that is to say, for example, also to various MDI types). Further isocyanates can also be present, like hexamethylene diisocyanate (HDI) and oligomers thereof or naphthylene diisocyanate (NDI). The totality of all isocyanates used in the production of a polyurethane material is referred to as the isocyanate composition (of the polyurethane material). The isocyanate composition comprises at least one isocyanate.

[0103] The conversion according to step (viii) can be achieved, for example, by phosgenation or also by salt-free conversion. Suitable methods are, for example, liquid phosgenation, gas-phase phosgenation or gas-liquid phosgenation or by phosgenation or salt-free conversion of a salt (for example, carbamate cleavage). Suitable conditions for phosgenation are known in principle to the person skilled in the art and are, for example, disclosed in Ullmann's Encyclopedia of Industrial Chemistry, 7thEdition, Volume 20, 2012, pages 63-82, WO 99 / 54289 A, WO 2004 / 056756 A (liquid phosgenation); Ullmann's Encyclopedia of Industrial Chemistry, 4thEdition, Volume 13, 2012, page 353, DE 25 870 847 A, EP 1532107 A, EP 0570799 A, EP 0289840 A (gas-phase phosgenation); or EP 2044009 A1, WO 2013 / 060836 A, WO 2013 / 079517 A (gas-liquid phosgenation). Examples of gas-liquid phosgenation processes are disclosed in WO 2022 / 106716, examples of gas-phase phosgenation processes are disclosed in EP 1761483 B1, EP 2079684 B1, EP 2188247 B1, EP 2408738 B1 and EP 2539314 B1, and examples of salt-free conversion are disclosed in WO 2018 / 185168 and EP 3 250 622 B1.

[0104] Preferably, the phosgenation comprises admixing a solvent to the amine component and stirring, more preferably at a temperature in the range of 50 °C to 180 °C, more preferably in the range of 70 °C to 140 °C, more preferably in the range of 80 °C to 120 °C, thereby obtaining a polyamine mixture; and contacting the polyamine mixture with phosgene in a reactor and heating the obtained mixture to a temperature in the range of 90 °C to 140 °C, more preferably in the range of 110 °C to 130 °C, thereby obtaining a mixture comprising one or more polyisocyanates.

[0105] The present application also relates to an isocyanate composition obtained or obtainable according to the process as disclosed above. Furthermore, the present application relates to the use of an isocyanate composition according to the present application or obtained or obtainable according to the process according to the present application for the preparation of a polyurethane. For example, TDI or MDI produced according to the present application can be used as isocyanate substance to produce a polyurethane material by reacting it with a polyol according to the present application or any other suitable polyol component.

[0106] In embodiments, the recycled amine material obtained by the process according to the present application can be phosgenated together with virgin MDA or TDA to obtain virgin-like isocyanates, which can also be used for the production of polyurethane materials.

[0107] The produced polyurethane materials can be used in any suitable polyurethane application, preferably in the same application. The polyurethane materials can for example be used in mattresses, furniture parts or car seats (TDI), or in electrical or construction applications (mainly pMDI).

[0108] Further embodiments of the present application can be found in the claims and examples. It is understood that the features of the subject-matter / method / use according to the present application mentioned in the foregoing and explained in the following can be used not only in the combinations specified each time, but also in other combinations, without departing from the scope of the present application. For example, the combination of preferred features with particularly preferred features, or the combination of features not characterized further with particularly preferred features, etc. is thus also implicitly covered, even if this combination is not explicitly mentioned.

[0109] 1. A process for recycling waste containing polyurethane comprising grafting polyol, the process comprising the steps of

[0110] a) providing a composition comprising comminuted polyurethane foam, the comminuted polyurethane foam comprising grafting polyol;

[0111] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis, hydrolysis, or hydrolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture;

[0112] c) optionally adjusting the water content to achieve phase separation;

[0113] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase.

[0114] 2. The process according to embodiment 1, wherein the depolymerization according to step b) is carried out by a process comprising a hydrolysis step together with the application of an alcoholysis, an aminolysis or an aminolysis.

[0115] 3. The process according to embodiment 1 or 2, wherein step c) is carried out and the water content is adjusted in the range of 0.1 to 1 wt.-%, based on the reaction mixture.

[0116] 4. The process according to any one of embodiments 1 to 3, wherein the process comprises a further purification step.

[0117] 5. The process according to any one of embodiments 1 to 4, wherein the process further comprises step a1) and / or step a2)

[0118] a1) sorting the foams using optical methods, in particular NIR spectroscopy;

[0119] a2) at least partially extracting flame retardants from the comminuted polyurethane foams.

[0120] 6. The process according to any one of embodiments 1 to 5, wherein the process further comprises step e)

[0121] e) converting the amine component to obtain an isocyanate composition.

[0122] 7. A process for recycling waste containing polyurethane containing graft polyols, the process comprising the steps of

[0123] a) providing a composition comprising comminuted polyurethane foams, the comminuted polyurethane foams comprising graft polyols;

[0124] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-% based on the reaction mixture;

[0125] c) optionally adjusting the water content to achieve phase separation;

[0126] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase;

[0127] e) converting the amine component to obtain an isocyanate composition.

[0128] 8. A polyol composition which is obtained or obtainable according to the process according to any one of embodiments 1 to 7.

[0129] 9. A polyol composition which is obtained or obtainable according to a process for recycling waste containing polyurethane containing graft polyols, the process comprising the steps of

[0130] a) providing a composition comprising comminuted polyurethane foams, the comminuted polyurethane foams comprising graft polyols;

[0131] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-% based on the reaction mixture;

[0132] c) optionally adjusting the water content to achieve phase separation;

[0133] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase.

[0134] 10. Use of the polyol composition according to embodiment 8 or 9 or obtained or obtainable according to the process of any one of embodiments 1 to 7 for the production of a polyurethane.

[0135] 11. An isocyanate composition which is obtained or obtainable according to the process of any one of embodiments 1 to 7.

[0136] 12. An isocyanate composition which is obtained or obtainable according to a process for recycling waste containing polyurethanes containing grafted polyols, the process comprising the steps of

[0137] a) providing a composition comprising a comminuted polyurethane foam, the comminuted polyurethane foam comprising grafted polyols;

[0138] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture;

[0139] c) optionally adjusting the water content to achieve phase separation;

[0140] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase.

[0141] 13. Use of the isocyanate composition according to embodiment 11 or 12 or obtained or obtainable according to the process of any one of embodiments 1 to 7 for the production of a polyurethane.

[0142] 14. A process for recycling waste containing polyurethanes containing grafted polyols, the process comprising the steps of

[0143] a) providing a composition comprising a comminuted polyurethane foam, the comminuted polyurethane foam comprising grafted polyols;

[0144] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture;

[0145] c) optionally adjusting the water content to achieve phase separation;

[0146] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase.

[0147] 15. The process according to embodiment 14, wherein the depolymerization according to step b) is carried out by a method comprising a hydrolysis step together with the application of alcoholysis, ammonolysis or aminolysis.

[0148] 16. The process according to embodiment 14 or 15, wherein step c) is carried out and the water content is adjusted in the range of 0.1 to 1 wt.-% based on the reaction mixture.

[0149] 17. The process according to any one of embodiments 14 to 16, wherein the process comprises a further purification step.

[0150] 18. The process according to any one of embodiments 14 to 17, wherein the process further comprises step a1) and / or step a2)

[0151] a1) sorting the foams using optical methods, in particular NIR spectroscopy;

[0152] a2) at least partially extracting flame retardants from the comminuted polyurethane foams.

[0153] 19. The process according to any one of embodiments 14 to 18, wherein the process further comprises step e)

[0154] e) converting the amine component to obtain an isocyanate composition.

[0155] 20. A process for recycling waste containing polyurethane comprising grafted polyols, the process comprising the steps

[0156] a) providing a composition comprising comminuted polyurethane foams, the comminuted polyurethane foams comprising grafted polyols;

[0157] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-% based on the reaction mixture;

[0158] c) optionally adjusting the water content to achieve phase separation;

[0159] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase;

[0160] e) converting the amine component to obtain an isocyanate composition.

[0161] 21. A polyol composition obtained or obtainable according to the process of any one of embodiments 14 to 20.

[0162] 22. A polyol composition obtained or obtainable according to a process for recycling waste containing polyurethanes containing graft polyols, the process comprising the steps of

[0163] a) providing a composition comprising a comminuted polyurethane foam, the comminuted polyurethane foam comprising a graft polyol;

[0164] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture;

[0165] c) optionally adjusting the water content to achieve phase separation;

[0166] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase.

[0167] 23. Use of the polyol composition of embodiment 21 or 23 or a polyol composition obtained or obtainable according to the process of any one of embodiments 14 to 20 for the preparation of a polyurethane.

[0168] 24. An isocyanate composition obtained or obtainable according to the process of any one of embodiments 14 to 20.

[0169] 25. An isocyanate composition obtained or obtainable according to a process for recycling waste containing polyurethanes containing graft polyols, the process comprising the steps of

[0170] a) providing a composition comprising a comminuted polyurethane foam, the comminuted polyurethane foam comprising a graft polyol;

[0171] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis- alcoholysis, hydrolysis-ammonolysis or hydrolysis- aminolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-%, based on the reaction mixture;

[0172] c) optionally adjusting the water content to achieve phase separation;

[0173] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase.

[0174] 26. Use of the isocyanate composition according to embodiment 24 or 25 or an isocyanate composition obtained or obtainable according to the method of any one of embodiments 14 to 20 for the preparation of a polyurethane.

[0175] 27. A process for recycling waste containing polyurethane comprising grafting polyol, the process comprising the steps of

[0176] a) providing a composition comprising a comminuted polyurethane material, the comminuted polyurethane material comprising grafting polyol;

[0177] b) depolymerizing the comminuted polyurethane provided in step a) by hydrolysis, hydrolysis, hydrolysis, or hydrolysis, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.-% based on the reaction mixture;

[0178] c) optionally adjusting the water content to achieve phase separation;

[0179] d) separating the amine component and the polyol component obtained in step b) or step c) into an amine-rich phase and an amine-lean phase,

[0180] wherein the grafting polyol content of the polyurethane material is in the range of 2.5% to 30% by weight of the polyurethane material.

[0181] 28. The process according to embodiment 27, wherein the depolymerization according to step b) is carried out by a method comprising a hydrolysis step together with the application of an alcoholysis, an aminolysis or an aminolysis.

[0182] 29. The process according to embodiment 27 or 28, wherein step c) is carried out and the water content is adjusted in the range of 0.1 to 1 wt.-% based on the reaction mixture.

[0183] 30. The process according to any one of embodiments 27 to 29, wherein the process comprises a further purification step.

[0184] 31. The process according to any one of embodiments 27 to 30, wherein the process further comprises step a1) and / or step a2)

[0185] a1) sorting the materials using optical methods, in particular NIR spectroscopy;

[0186] a2) at least partially extracting flame retardants from the comminuted polyurethane material.

[0187] 32. The process according to any one of embodiments 27 to 31, wherein the process further comprises step e)

[0188] e) converting the amine component to obtain an isocyanate composition.

[0189] 33. A polyol composition obtained or obtainable according to the process of any one of embodiments 27 to 32.

[0190] 34. Use of a polyol composition according to embodiment 33 or a polyol composition obtained or obtainable according to the process of any one of embodiments 27 to 32 for the preparation of a polyurethane.

[0191] 45. An isocyanate composition obtained or obtainable according to the process of any one of embodiments 27 to 32.

[0192] 46. Use of an isocyanate composition according to embodiment 45 or an isocyanate composition obtained or obtainable according to the process of any one of embodiments 27 to 32 for the preparation of a polyurethane.

[0193] Illustrative embodiments of the present application are set out below, but these embodiments do not limit the present application. In particular, the present application also encompasses those embodiments resulting from the combination of the attributes specified below and therefore. Examples

[0194] In the following, preferred examples are described in detail:

[0195] For all examples described below, wt.-% is given relative to the respective mixture, equal total weight.

[0196] For the example,

[0197] A polyurethane foam without SAN was used. For the release yield, the following expectation value, i.e. the amount obtainable in theory, was used:

[0198] - 23 wt.-% toluenediamine,

[0199] A polyurethane foam with 15 wt. % grafted polyol (including SAN) was used. For the release yield, the following expectation value, i.e. the amount obtainable in theory, was used:

[0200] - 23 wt.-% toluenediamine,

[0201] A scrap polyurethane foam with about 3-5 wt. % grafted polyol (including SAN) was used. For the release yield, the following expectation value, i.e. the amount obtainable in theory, was used:

[0202] - 21.4 wt.-% toluenediamine, determined by HPLC. Furthermore, the complete conversion was checked by IR.

[0203] The remaining amount is mainly composed of the additive and losses due to carbon dioxide formation during hydrolysis. It is expected that the polyurethane material comprises about 2 moles of functional groups per kg (kilogram) of polyurethane material. In this respect, the functional groups are carbamate groups (0.6 moles) and urea groups (1.4 moles).

[0204] Examples for recycling PU flexible foams with SAN content > 0.1 wt.%:

[0205] Example 1 : (according to the application)

[0206] A polyurethane foam of known composition with a grafted polyol content of 15 wt.-% and a polyurethane foam of known composition without SAN are mixed to obtain a total SAN content of 5 wt.-%. This foam mixture (50 wt.-% of the reaction mixture) is dosed in diethylene glycol (41.8 wt.-%) as alcoholysis substance at 200 °C within 15 min in the presence of KOH (solid; 1 wt.-%). 10 min after the last foam is added to the reaction mixture, water (7.2 wt.-%) is added and all substances are stirred at 130 °C under N2 (or air) and at normal pressure (1013.25 mbar) with reflux condenser for 2 h. Then, water is removed by distillation at normal pressure (1013.25 mbar) for 1 h until the temperature of the reaction mixture rises to 175 °C when heating and stirrer are stopped. Phase separation occurs within a few minutes.

[0207] Then, the resulting mixture is cooled to 80 °C and kept for 16 h for further phase separation. The second phase (lower phase, rich in diethylene glycol) is separated.

[0208] The composition of the first phase (upper phase, rich in polyol substance) comprises 64 wt.-% polyol, 25.3 wt.-% diethylene glycol, 9.3 wt.-% toluenediamine, 0.07 wt.-% potassium and 0.7 wt.-% water.

[0209] The composition of the second phase comprises 67.4 wt.-% diethylene glycol, 16.1 wt.-% toluenediamine and 1.3 wt.-% potassium.

[0210] The phase separation is successful and the release of 97 % of the expected toluenediamine indicates a complete conversion.

[0211] Example 2: (according to the application)

[0212] A polyurethane foam of known composition with a grafted polyol content of 15 wt.% and a polyurethane foam of known composition without SAN were mixed to obtain a total SAN content of 10 wt.%. This foam mixture (50 wt.% of the reaction mixture) was dosed in diethylene glycol (41.3 wt.%) as alcoholysis substance at 200 °C within 15 min in the presence of KOH (solid; 1.3 wt.%). 10 min after the last foam was added to the reaction mixture, water (7.5 wt.%) was added and all substances were stirred at 125 °C with reflux condenser under N2 (or air) and at normal pressure (1013.25 mbar) for 2 h. Then, water was removed by distillation at normal pressure (1013.25 mbar) for 1 h until the temperature of the reaction mixture increased to 180 °C when heating and stirrer were stopped. Phase separation occurred within a few minutes.

[0213] Then, the resulting mixture was cooled to 80 °C and kept for 16 h for further phase separation. The second phase (lower phase, rich in diethylene glycol) was separated.

[0214] The first phase (upper phase, rich in polyol substances) was further treated by filtration (20 pm mesh size).

[0215] The composition of the filtered first phase included 68 wt.-% polyol, 21.6 wt.-% diethylene glycol, 9.4 wt.-% toluenediamine, 0.19 wt.-% potassium and 0.7 wt.-% water.

[0216] The composition of the second phase included 57.7 wt.-% diethylene glycol, 14.9 wt.-% toluenediamine, 1 wt.-% potassium and 0.4 wt.-% water.

[0217] The phase separation was successful and the release of 97% of the expected toluenediamine indicated a complete conversion.

[0218] Example 3: (according to the application)

[0219] A sorted mixture of a scrap polyurethane flexible foam having a graft polyol content of about 3-5 wt.%, based on NIR-measurements; 48 wt.% of the reaction mixture, was dosed into diethylene glycol (43.6 wt.%) as alcoholysis substance in the presence of KOH (solid; 1.2 wt.%) at 200 °C within 15 min. 10 min after the last foam was added to the reaction mixture, water (7.2 wt.%) was added and all substances were stirred at 135 °C under N2 (or air) and at normal pressure (1013.25 mbar) with reflux condenser for 2 h. Then, water was removed by distillation at normal pressure (1013.25 mbar) for 1 h until the temperature of the reaction mixture increased to 190 °C when heating and stirrer were stopped. Phase separation occurred within a few minutes.

[0220] Then, the resulting mixture was cooled to 80 °C and kept for 16 h for further phase separation. The second phase (lower phase, rich in diethylene glycol) was separated.

[0221] The composition of the first phase (upper phase, rich in polyol substance) included 65 wt.-% polyol, 23.5 wt.-% diethylene glycol, 8.7 wt.-% toluenediamine, 0.26 wt.-% potassium and 0.45 wt.-% water.

[0222] The composition of the second phase included 68.3 wt.-% diethylene glycol, 13.6 wt.-% toluenediamine and 1.4 wt.-% potassium.

[0223] The phase separation was successful and the release of 89% of the expected toluenediamine indicates a very high conversion. The expected amount of toluenediamine was determined by elemental analysis for nitrogen in the scrap foam mixture. In case of acrylonitrile of the SAN-particles, the expected amount of toluenediamine was overestimated. Therefore, the release of 89% of the expected toluenediamine indicates a very high conversion.

[0224] Example 4: (comparative example)

[0225] A sorted mixture of scrap polyurethane flexible foam having a graft polyol content of about 3-5 wt. % (measured according to NIR; 51.6 wt. % of the reaction mixture) was dosed in diethylene glycol (43 wt. %) as alcoholysis substance in the presence of KOH (solid; 1.5 wt. %) at 200 °C within 15 min. 10 min after the last foam was added to the reaction mixture, water (3.8 wt. %) was added and all substances were stirred at 170 °C under N2 (or air) and at normal pressure (1013.25 mbar) with reflux condenser for 2 h. Then, water was removed by distillation at normal pressure (1013.25 mbar) for 1 h until the temperature of the reaction mixture increased to 180 °C when heating and stirrer were stopped.

[0226] Then, the resulting mixture was cooled to 80 °C and kept at 80 °C for 16 h. Due to the high viscosity and high solids content, no phase separation was obtained. Filtering the solids was not possible using a filter with a mesh size of 20 pm due to filter clogging. Cited literature

[0227] CN 106700126

[0228] US 20010027246

[0229] EP 1 142 945 A2

[0230] US 9,023,907 B2

[0231] WO 2015 / 121057

[0232] WO 2013 / 139781

[0233] "Kunststoffhandbuch [Plastics handbook], volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, chapter 3.1, 3.2 and 3.3.2

[0234] WO 2006 / 034800

[0235] EP 0090444

[0236] WO 2005 / 090440

[0237] WO 2022 / 171586

[0238] US 2022 / 0251328

[0239] EP 22178796.3

[0240] EP 22178797.1

[0241] Ullmann's Encyclopedia of Industrial Chemistry, 7 th ed. Vol. 20, 2012, p. 63-82

[0242] WO 99 / 54289 A

[0243] WO 2004 / 056756 A

[0244] Ullmann's Encyclopedia of Industrial Chemistry, 4 th ed. Vol. 13, 2012, p. 353

[0245] DE 25 870 847 A

[0246] EP 1532107 A

[0247] EP 0570799 A

[0248] EP 0289840 A

[0249] EP 2044009 A1

[0250] WO 2013 / 060836 A

[0251] WO 2013 / 079517 A

[0252] WO 2022 / 106716

[0253] EP 1761483 B1

[0254] EP 2079684 B1

[0255] EP 2188247 B1

[0256] EP 2408738 B1

[0257] EP 2539314 B1

[0258] WO 2018 / 185168

[0259] EP 3 250 622 B1.

Claims

1. A method for recycling waste containing polyurethane grafted with polyols, the method comprising the following steps: a) Provides a composition comprising pulverized polyurethane material, the pulverized polyurethane material comprising grafted polyol; b) Depolymerizing the pulverized polyurethane provided in step a) by hydrolysis, hydroalcoholization, hydroammonolysis or hydroamineization, wherein the water content in the reaction mixture is in the range of 3.5 to 15 wt.% based on the reaction mixture; c) Optionally, the water content can be adjusted to achieve phase separation; d) Separate the amine and polyol components obtained in step b) or step c) into amine-rich and amine-poor phases.

2. The method according to claim 1, wherein, The depolymerization according to step b) is carried out by a method including a hydrolysis step, which is performed in conjunction with the application of alcoholysis, ammonolysis or aminolysis.

3. The method according to claim 1 or 2, wherein, Proceed to step c) and adjust the water content to a range of 0.1 to 1 wt.% based on the reaction mixture.

4. The method according to any one of claims 1 to 3, wherein, This method includes an additional purification step.

5. The method according to any one of claims 1 to 4, wherein, The method further includes step a1) and / or step a2). a1) These materials are sorted using optical methods, especially NIR spectroscopy; a2) Extract at least partially the flame retardant from the pulverized polyurethane material.

6. The method according to any one of claims 1 to 5, wherein, The method further includes step e). e) Convert the amine component to obtain an isocyanate composition.

7. A polyol composition which is obtained or is obtainable according to any one of claims 1 to 6.

8. Use of the polyol composition according to claim 7 or a polyol composition obtained or obtainable according to any one of claims 1 to 6 for the preparation of polyurethane.

9. An isocyanate composition which is obtained or is available according to any one of claims 1 to 6.

10. Use of the isocyanate composition according to claim 9 or the isocyanate composition obtained or obtainable according to any one of claims 1 to 6 for the preparation of polyurethane.