Process for autocatalytic hydroglycolytic or hydrolytic cleavage of waste streams containing polyurethane

Abstract

The present invention is directed to a process for cleavage recycling of polyurethane or polyisocyanurate foams containing waste comprising the steps of providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate (I1), and depolymerization of the comminuted polyurethane or polyisocyanurate, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). The present invention further relates to a polyol composition obtained or obtainable according to said process and the use thereof for the preparation of polyurethanes or polyisocyanurates.

Description

[0001] Process for autocatalytic hydroglycolytic or hydrolytic cleavage of waste streams con- taining polyurethane The present invention is directed to a process for cleavage recycling of polyurethane or polyiso- cyanurate foams containing waste comprising the steps of providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate compo- sition (IC) comprising isocyanate (I1), and depolymerization of the comminuted polyurethane or polyisocyanurate, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). The present invention further relates to a polyol composition obtained or obtainable according to said process and the use thereof for the preparation of polyurethanes or polyisocyanurates. The recycling of waste streams represents an essential building block for achieving greater sus- tainability of existing value chains. In material cycles of plastics, remonomerizations as recycling techniques are those with the greatest circularity. In the field of plastics, polyurethane plastics are a large-volume group. Polyurethanes are formally prepared by polyaddition of at least one polyol with at least one polyisocyanate. One remonomerization strategy discussed in the literature and in patents, among others, is hy- droglycolysis, in which an initially formed carbamate is subsequently hydrolyzed to the corre- sponding amine with carbon dioxide evolution. The process can be carried out in one or two steps. Numerous basic amines, alkali metal and alkaline earth metal hydroxides are disclosed in the literature as catalysts for hydroglycolysis. CN106700126 discloses a method for self-catalytic degradation and recycling of polyurethane foams. The process is applied for the recycling of polyurethane waste material. US20010027246 discloses a method of recovering a decomposition product from a polyurethane, the method comprising the steps of thermally decomposing a polyurethane into a liquid containing a polyol and a urea compound which is soluble in the polyol, and solids containing a urea com- pound which is insoluble in the liquid in the presence of a polyamine compound at a temperature of 120 to 250°C; removing the solids; hydrolyzing the residue with water retained at a high tem- perature of 200 to 320°C and a high pressure; and recovering the resulting polyamine and / or polyol. EP 1142945 A2 relates to a method of chemically decomposing the cuttings made in molding or fabricating articles of polyurethane resins and waste of such resin articles for industrially advan- tageous recovery of a polyamine compound and a polyol compound useful as the raw materials of the polyurethane resin. According to CN1275587 a polyurethane waste material is decomposed in aqueous solution, and the catalyst is separated in the water-phase so as to be used cyclically. The decomposed product polyether and toluene diamine can be separated in water. WO2022 / 063764 discloses a process for the recovery of raw materials (i.e. polyols and option- ally additional amines) from polyurethane products, comprising the reaction of the polyurethane product with an alcohol in the presence of a catalyst. A product mixture containing alcohol, poly- ols and carbamates and optionally water is obtained. The carbamates may be hydrolyzed with liberation of an amine corresponding to an isocyanate of the isocyanate component. In many processes, the problem is an irreversible reaction of the catalysts used with carbon di- oxide, especially in hydroglycolysis under pressure. On the one hand, this leads to a reduced yield of polyols and amine monomers. In addition, insoluble solids are formed, which make downstream processing technically very difficult. The circularity of the catalyst is also no longer given. Accordingly, it was an object to provide a process for recycling polyurethane-containing waste streams in such a way that maximum yields of polyols and amine monomers can be achieved while simplifying technical workup and ensuring the circularity of the catalyst. The problem is solved according to the present invention by a process for recycling of polyure- thane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from an isocyanate composition (IC) comprising isocyanate (I1); b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a), wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). The present invention also relates to a process for recycling of polyurethane or polyisocyanu- rate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1 , b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a), wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1), wherein amine (A1) is supplied by at least proportional recycling of at least one of the amine- containing components occurring in the process. According to the process of the present invention, it is possible to recover both starting material components from the polyurethane. The polyurethane components are either recovered directly, for example the polyols, or are obtained as valuable synthesis building blocks such as polyam- ines which may readily be converted to polyisocyanates. In the context of the present invention, a “comminuted polyurethane or polyisocyanurate foam” means the material is obtained from a foam and the comminuted polyurethane or polyisocyanu- rate is for example used in shredded form, in the form of granules, flakes, as an agglomerate, or as a powder. The polyurethane or polyisocyanurate foams can be comminuted by conventional methods, for example by shredding, e.g. in a rotation mill or rotary mill at room temperature, to a particle size of ordinarily less than 500 mm, for example to a particle size in the range of from 10 to 500 mm, preferably to a particle size of less than 20 mm, or ground, e.g. by known cold grinding processes. Preferably, for a milled foam a particle size of less than 5 mm is selected, for example a particle size in the range of 0.01 mm to 5 mm, and preferably in the range of 0.01 mm to 1 mm. The properties of the polyurethane or polyisocyanurate foams might vary in broad ranges. Pref- erably, polyurethane foams are used in the process of the present invention. According to a fur- ther embodiment, the present invention is also directed to the process as disclosed above, wherein the polyurethane foams are selected from the group consisting of polyisocyanate de- rived polyurethane foams. The polyurethane or polyisocyanurate foams used in the present invention are preferably ob- tained from items produced from polyurethane foams at a time after use for the purpose for which they were manufactured or polyurethane foam waste from production processes. Before subjecting to the process of the present invention, the items may be subjected to sorting steps and / or to mechanical comminution. That is, further sorting and bringing the items into appropri- ate sizes, e.g., by shredding, sieving or separation by rates of density, i.e. by air, a liquid or magnetically. Optionally, these fragments may then undergo processes to eliminate impurities, e.g. paper labels. Furthermore, steps to remove blowing agents may be included in the process. Suitable methods are in principle known to the person skilled in the art. Herein, the term “polyurethane foam waste” includes end-of-life polyurethane foams and pro- duction rejects of PU foams or waste generated through further processing of PU foams. In this context, the term “spent polyurethane foam” denotes an item produced from a polyurethane foam at a time when it has already been used for the purpose for which it was manufactured. “Production rejects of polyurethane foams“ denotes polyurethane foam waste occurring in pro- duction processes of PU foams. Generally, polyurethane foams are produced by a reaction between a polyisocyanate compo- nent and a polyol component. Typically, further materials, in particular additives, such as for ex- ample flame retardants (e.g. phosphorous-based), polymerization catalysts (e.g. tertiary amines), fillers and surfactants as siloxanes can be added in the production process of the poly- mers. The properties of a polyurethane foam are influenced by the chemistry of polyisocyanate and polyol components used and the recipe applied in polymerisation. For example, the starting ma- terials may influence the crosslinking density of the polymers in a three-dimensional network. Rigid polyurethane are typically obtained from monomers with a comparably low molecular weight and high functionality creating a highly crosslinked, dense network. Industrially and consequently in large quantities, especially methylenedi(phenylisocyanate) (MDI) or its polymeric forms or tolylene 2,4 and 2,6-diisocyanate (TDI) are used as polyisocya- nate components for the production of PU rigid foams and PU flexible foams. For a representa- tive composition of these PU foams, see for example US 9,023,907 B2, WO 2015 / 121057 and WO 2013 / 139781. Organic polyisocyanates that can be used in the preparation of polyurethanes are any of the known organic polyisocyanates, preferably aromatic polyfunctional isocyanates. In the context of the present invention, the term polyisocyanate encompasses isocyanates with 2 or more iso- cyanate groups, i.e. also diisocyanates. Suitable polyisocyanate components used for the production of the polyurethanes or polyisocy- anurates comprise any of the polyisocyanates known for the production of polyurethanes or pol- yisocyanurates. These comprise the aliphatic, cycloaliphatic, and aromatic difunctional or poly- functional isocyanates known from the prior art, and also any desired mixtures thereof. Exam- ples are diphenylmethane 2, 2’-, 2,4’-, and 4,4’-diisocyanate, the mixtures of monomeric diphe- nylmethane diisocyanates with diphenylmethane diisocyanate homologs having a larger number of rings (polymer MDI), isophorone diisocyanate (IPDI) and its oligomers, tolylene 2,4- and 2,6- diisocyanate (TDI), and mixtures of these, tetramethylene diisocyanate and its oligomers, hexa- methylene diisocyanate (HDI) and its oligomers, naphthylene diisocyanate (NDI), and mixtures thereof. Preferably, tolylene 2,4- and / or 2,6-diisocynate (TDI) or a mixture thereof, monomeric diphenyl- methane diisocyanates, and / or diphenylmethane diisocyanate homologs having a larger num- ber of rings (polymer MDI), and mixtures of these. Other possible isocyanates are mentioned by way of example in "Kunststoffhandbuch [Plastics handbook], volume 7, Polyurethane [Polyure- thanes]", Carl Hanser Verlag, 3rd edition 1993, chapter 3.2 and 3.3.2. The organic polyisocyanates may be used individually or in the form of mixtures. Common polyols used in huge quantities are, e.g., selected from the group consisting of poly- ether polyols, polyester polyols, polyetherester polyols and mixtures thereof. Polyetherols are by way of example produced from epoxides, for example propylene oxide and / or ethylene oxide, or from tetrahydrofuran with starter compounds exhibiting hydrogen-ac- tivity, for example aliphatic alcohols, phenols, amines, carboxylic acids, water, or compounds based on natural substances, for example sucrose, sorbitol or mannitol, with use of a catalyst. Mention may be made here of basic catalysts and double-metal cyanide catalysts, as described by way of example in WO 2006 / 034800, EP 0090444, or WO 2005 / 090440. Polyesterols are by way of example produced from aliphatic or aromatic dicarboxylic acids and polyhydric alcohols, polythioether polyols, polyesteramides, hydroxylated polyacetals, and / or hydroxylated aliphatic polycarbonates, preferably in the presence of an esterification catalyst. Other possible polyols are mentioned by way of example in "Kunststoffhandbuch [Plastics hand- book], volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, chapter 3.1. Polyesterpolyols may for example be selected from polyester alcohols whose OH numbers are in the range from 25 to 800 mg KOH / g, in particular from 25 to 500 mgKOH / g, preferably from 25 to 350 mgKOH / g, particularly preferable from 30 to 70 mgKOH / g. The polyester alcohols used are mostly prepared via condensation of polyhydric alcohols, preferably polyetherpolyols with a molecular weight up to 800 g / mol, preferably up to 650 g / mol, or diols, having from 2 to 12 carbon atoms, preferably from 2 to 6 carbon atoms, with polybasic carboxylic acids having from 2 to 12 carbon atoms, e.g. succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, or preferably phthalic acid, isophthalic acid, terephthalic acid, or the isomeric naphthalenedicarboxylic acids. Also cy- clic anhydrides may be used such as for example phthalic acid dianhydride. After depolymerization, the process of the invention typically yields a polyamine comprising an amino group attached to the carbon atom to which in the initial polyisocyanate an isocyanate group was bound, e.g., methylene diphenyl diamines (MDA), oligomeric and polymeric meth- ylene phenylene amine and toluenediamines (TDA), in particular 2,4 toluenediamine or 2,6-tolu- enediamine, hexamethylene diamine (HDA), or naphthylene diamines (NDA). The commonly used polyols as described above preferably also can be re-isolated. Thus, the process prefera- bly further yields, e.g., polyester polyols, fragments of polyesterpolyols, low molecular weight polyols such as ethylene glycol or propylene glycol, or high molecular weight polyether polyols based on glycerol, sorbitol, ethylene glycol, polypropylene glycol and polytetramethylene glycol. The process of the present invention comprises steps a) and b) and may comprise further steps. According to step a), a composition comprising a comminuted polyurethane or polyisocy- anurate foam which is obtained from an isocyanate composition (IC) comprising isocyanate (I1) is provided. The composition might contain further components, for example solvents. Accord- ing to step b), the comminuted polyurethane or polyisocyanurate provided in step a) is depoly- merized, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). Typically, the depolymerization results in polyol components and amine components. After work-up, the polyol-containing phase may be used at least proportionally in new PU formu- lations. After purification, the polyamine preferably can be converted back to the corresponding isocyanate, for example by means of phosgenation, and as such can then be used at least pro- portionally as an isocyanate component in PU production. It has surprisingly been found that it is possible to use amine monomers obtainable in the depol- ymerization process as catalyst in the depolymerization step, in particular in a hydroglycolysis step. In case the complementary amine to isocyanate (I1) is used as catalyst in the hydroglycol- ysis, said amines react with CO2 to unstable carbamic acids under pressure and by their de- composition free amine is generated in turn which acts as catalyst and accelerates the reaction autocatalytically. Advantageously, the complementary amine has not to be separated off in the process. Preferably, at least one of the amine-containing streams formed during the reaction or work-up is completely or in parts recycled in the reaction stage to introduce the amine as a catalyst. In this way, the catalyst is recovered in the course of the reaction. According to a further embodiment, the present invention is also directed to the process as dis- closed above, wherein the amine (A1) is prepared in the process itself, in particular wherein the amine (A1) is prepared in the process itself and is supplied by at least proportional recycling of at least one of the amine-containing components occurring in the process. According to a further embodiment, the present invention is also directed to the process as dis- closed above, wherein at least one of the amine-containing streams formed during the reaction or work-up is completely or in parts recycled in the reaction stage to introduce the amine as a catalyst. Amine-containing components may be present in the process according to the present invention for example during the removal of particulate solids from the reaction mixture obtained in step b) or during phase separation in a polyol-containing phase and an amine-containing phase or dur- ing the distillative work-up of the amine phase, comprising alcohol, water and corresponding amine or during the purification of polyol-containing phase under recovery of a purified polyol. Suitable methods for depolymerization are in principle known to the person skilled in the art. Preferably, the depolymerization is achieved by hydrolysis, hydroglycolysis, or by aminolysis ac- cording to the present invention. Preferably, depolymerization is achieved by hydroglycolysis or hydrolysis according to the present invention. In principle, also the alcoholysis and glycolysis are suitable methods for the depolymerization. However, in the case of glycolysis / alcoholysis, the depolymerization leads primarily to carba- mates, a polyaddition product of the utilized glycol or alcohol with the isocyanate component and not the respective amine of the isocyanate component. The autocatalytic behavior of the reaction cannot be achieved. Indeed, urea groups which are formed during the foaming process by adding water can be depolymerized to isocyanate derived amines. However, because of the equilibrium reaction for the glycolysis / alcoholysis only small amounts of amines are formed which typically will accelerate the reaction rate more likely for the carbamate formation as the amine formation. Depending on the method used for depolymerization, different products are obtained. Prefera- bly, it is possible to recover both starting material components from the polyurethane. Typically, a component comprising an isocyanate precursor like an amine, carbamate or urea is obtained and can be separated but also the polyol component or monomer fragments of the polyol com- ponent is separated, In the context of the present invention, the amine component is to be un- derstood as a component obtained in the depolymerization process comprising an isocyanate precursor like an amine, carbamate or urea. Usually, the depolymerization results in a mixture of components which might be separated us- ing suitable separation techniques. The process of the present invention may also comprise fur- ther separation steps. According to a further embodiment, the present invention is also directed to the process as dis- closed above, wherein the depolymerization according to step b) is carried out by a method se- lected from hydrolysis or hydroalcoholysis, in particular hydroglycolysis. Suitable conditions for the depolymerization are in principle known to the person skilled in the art. According to the present invention, further additives including solvents or further catalytically active component may be added in step b). Preferably, the depolymerization is carried out with- out the addition of further catalyst. The resulting products of the depolymerization may be sepa- rated using suitable separation techniques which are in principle known to the person skilled in the art. In particular for recovering an amine substance, it is beneficial if a polyurethane material is alco- holised by contacting the polyurethane material with an alcoholising substance, wherein water is added in an amount so that a water content of a resulting mixture is from about 0.2 eq. to about 30 eq. water, in particular about 1 eq. to about 20 eq. water, in particular about 1.15 eq. to about 10 eq., for example about 1.3 eq. to about 5 eq., for example about 1.4 eq. to about 2 eq., based on the amount of cleavable bonds in the polyurethane material. During the alcoholising, i.e., alcoholysis, of the polyurethane material, an amine substance and a polyol substance are formed. Eq. (i.e., equivalents) refers to equivalents per cleavable bond of the polyurethane material. Cleavable bonds are defined as urethane bonds,urea bonds and isocyanurate bonds within the polyurethane material and include segments in the polyurethane material in which segments are linked via allophanate units as well as linkages via biuret groups. Basically, the amount of cleav- able bonds is equivalent to the amount of the isocyanate group content in the original polyure- thane material. Preferably, the depolymerization is carried out by hydroglycolysis according to the present in- vention. Suitable conditions for hydroglycolysis are in principle known to the person skilled in the art. The hydroglycolysis reaction may for example be conducted in a stirred reactor tank at a tempera- ture in the range of from 170 to 250°C at a pressure in the range of from 1 to 50 bar. After depolymerization according to step b), typically a mixture of reaction products is obtained. Preferably, the process further comprises allowing the mixture to settle, wherein one or more phases are formed. The process according to the present invention comprises steps a), and b), and optionally c) but may also comprise further steps. The process may for example comprise further purification steps or heat treatments. According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the process comprises further purification steps. Suitable treatment steps are in principle known to the person skilled in the art. Suitable treatment and / or purification steps may be carried out between steps a) and b), or between steps b) and c). In the context of the present invention it is also possible that step b) is carried out directly after step a). It is also possible that step c) is carried out directly after step b). According to the present invention, steps a) and b) might also be combined and carried out in the same apparatus. It is also possible that the composition provided in step a) might also comprise solvents, for example solvents which might be used in step b) of the process according to the present invention. The work-up of the depolymerization product, in particular the isolation of the polyamine and the polyol can be realized case dependent, for example by extractive work-up, precipitation of the amine component as a hydrochloride, as a urea (in case of an aminolysis), chromatography or distillation under reduced pressure. Preferably, the work up comprises several steps. According to one aspect of the invention, solids may be removed from the mixture before or af- ter the mixture is allowed to settle, preferably by one or more of the following: filtration, centrifu- gation, decantation. According to a further embodiment, the present invention is also directed to the process as dis- closed above, wherein the process further comprises a step c) c) removal of particulate solids from the reaction mixture. Suitable methods for removal of particulate solids are in principle known to the person skilled in the art. For example filtration units or a centrifuge may be used. Preferably, a filtration step is carried out according to the present invention using a filtration unit, more preferably a filter, more preferably a pocket filter, a bag filter, a membrane filter, a candle filter, an agitated pres- sure filter, a vacuum belt filter, a frame & plate filter, or a nutsche filter. For filtration, preferably filter membranes having an average mesh size of about 30 μm or less may be used. It can be beneficial to use a cascade of filters. For example, a first filter mem- brane of the cascade of filters has an average mesh size of about 250 μm to about 290 μm. A second filter membrane of the cascade of filters preferably has an average mesh size of about 50 μm to about 90 μm and, in particular, a third filter membrane of the cascade of filters has an average mesh size of 20 μm or less. In the alternative or additionally, centrifugation is a preferred solid-liquid-separation method. Preferably, the process comprises allowing the mixture to settle. According to the present inven- tion, it is possible that one or more phases are formed and the components of the mixture may be separated by suitable separation steps. In particular in embodiments, in which the amine substance is recovered, it can be beneficial if an excess of water is removed from the mixture, before allowing the mixture to settle, preferably by evaporation of the excess of water. In particular, for evaporation of the excess of water, the mixture is heated and / or a vacuum is applied. For example, an excess of water is removed by using flash evaporation or applying vacuum to the already heated mixture. For example, a water removal step may be performed for about 120 minutes or less, in particular about 90 minutes or less, for example about 75 minutes or less, for example about 60 minutes or less. Preferably, the water removal step is performed for about 10 minutes or more, in particular for about 30 minutes or more, for example for about 40 minutes or more. According to a further embodiment, the present invention is also directed to the process as dis- closed above, wherein the process further comprise a step d) d) separation of the amine component and the polyol components. In work-up by distillation, compounds are separated according to their volatility, with more vola- tile compounds being separated first. Additives, water or solvents used in the depolymerization can also be removed via distillation prior further work-up of the polyol-polyamine mixtures. Gen- erally, the “volatility” of a liquid may be described using its vapor pressure, wherein a high vapor pressure indicates a high volatility, and vice versa. In the event that the polyamine is more volatile than the polyol as it is for example the case for TDA, monomeric MDA and NDA, the polyamine is recovered from the depolymerization product via distillation, preferably via distillation at reduced pressure. After distilling-off the polyamine, a distillation bottoms remains which contains the polyol. Suitable conditions for the distillation are in principle known to the person skilled in the art and are for example disclosed in EP22178796.3 or EP22178797.1. Alternatively, the polyol may be recovered by extraction from the depolymerization mixture us- ing a suitable extractant or a pair of extractants. It is also possible to precipitate the polyamine component in the form of it´s hydrochloride by adding HCl and extracting the polyol component with a suitable solvent for example as described in DE2854940A1, which is preferably dissolv- ing the polyol component but not the hydrochlorides of the polyamine component. The hydro- chloride of the polyamine component can after separation then either be transferred to the free polyamine by adding a base but also directly used in the phosgenation to generate new polyiso- cyanates for the polyurethane synthesize. In case of MDA*HCl or PMDA*HCl the hydrochloride can be directly fed to an MDA synthesis plant at a position prior to the neutralization step. Further, in particular for recovering the polyol substance, the process comprises preferably a work-up of the phase, which is polyol substance rich by purification of the polyol substance. The purification may for example comprise one or more of the following but may also comprise fur- ther purification steps: - filtration; - centrifugation; - decantation; - distillation; - full or partial evaporation of the phase in one or more evaporators; - contacting the phase with an ion exchange material; - contacting the phase with one or more adsorbents; -extracting the phase via one or more extraction agents. After the work-up, the phase, which is polyol substance rich, preferably an acid number 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. A mixture of iso-propanol / water 1:1 was used as solvent mixture, instead of toluene / ethanol 2:1. As a further change, NaOH / KOH was dissolved in methanol instead of ethanol. The OH numbers are in the range from 25 to 800 mg KOH / g, in particular from 25 to 500 mgKOH / g, preferably from 25 to 350 mgKOH / g, in particular from 30 to 70 mgKOH / g. According to the present invention, preferably a polyol component having a func- tionality of from 1 to 6, preferably between 1 to 4.5 is used, in particular in the range of from 1 to 4.1, more preferable in the range of from 1 to 3.9, most preferable in the range of from 1.1 to 3.5. Depending on the polyols present in the polyurethane or polyisocyanurate foam, the polyol com- ponent may comprise polyol fragments such as for example fragments of polyesterpolyols. Ac- cording to the present invention, the polyol components or polyol fragments may be treated to form a polyol. Typically, the phase may comprise polyol components such as glycols and may also comprise mono- or-diacids in case polyesterpolyols are present in the polyurethane or pol- yisocyanurate. Diacids may also be present in the form of diammonium salts. In case ammo- nium salts are present in the composition, the treatment may comprise further treatments such as for example thermal treatments and / or vapor stripping to obtain the free acid prior to re-ester- fication of the polyol fragments. Suitable conditions for example for re-esterfication are known to the person skilled in the art. The ratio of acids and polyalcohols is typically adjusted to obtain a mixture which is then suitable as a starting material for esterification of the acids and polyalco- hols. Preferably, the ratio of acids is adjusted to a molar ratio of acid groups to hydroxy groups in the range of from 1:1.03 to 1:2.5, in particular to 1:1.05 to 1:2.0. The process may for example comprise steps such as adding diacids to the mixture; adding pol- yalcohols to the mixture; adding esterification catalysts, for example titan tetrabutanolate; re- moval of diols by evaporation / distillation; or removal of solvent from the mixture. The process may furthermore comprise suitable treatment steps to achieve condensation of polyalcohols and acids in the mixture. In particular suitable to achieve re-condensation of polyols and acids. Suit- able conditions for example for re-esterfication are known to the person skilled in the art and may for example include condensation of alcohols and acids by heating under vacuum and re- moval of condensation product, online analytics to follow reaction progress and optionally adjust monomer composition. Preferably, the process further comprises work-up of the mixture by purification of the amine substance, for example including distillation, extraction, adsorption, precipitation or crystalliza- tion in order to purify the amine substance. It is understood that the separation process described above can be combined with any of the various embodiments of the inventive process described herein. With the process of the present invention, about 90 % or more, preferably about 97 % or more, of the polyol substances or monomer fragments of those which is theoretically recoverable from the polyurethane material can be released. Thus, the yield of the polyol substances or monomer fragments of those which are released is about 90 % or more, preferably of 97 wt.-% or more, in particular of 99 wt.-% or more. According to a further aspect, the present invention is also directed to the polyol composition obtained or obtainable according to the process of the present invention. Preferably, the polyol composition for flexible foams comprises or consists of one or more poly- ols having a molecular weight of about 2500 to about 3500 g / mole, a nominal OH functionality of about 3 and having an OH number of about 48 mg KOH / g to about 56 mg KOH / g. Preferably, the polyol composition for rigid foams comprises or consists of one or more polyols having a molecular weight of about 400 to about 800 g / mole, a nominal OH functionality of about 2-3 and having an OH number of about 200 mg KOH / g to about 300 mg KOH / g. Furthermore, according to a further embodiment, the polyol composition may comprise or con- sist of one or more polyols having a molecular weight of about 3000 to about 6500 g / mole, a nominal OH functionality of about 3 and having an OH number of about 20 mg KOH / g to about 50 mg KOH / g. According to a further aspect, the present invention is also directed to the use of the polyol com- position according to the present invention or a polyol composition obtained or obtainable ac- cording to the process of the present invention for the preparation of polyurethanes or polyiso- cyanurates. The present invention further relates to a process for preparing a polyurethane material by re- acting the polyol substance obtained by the process according to the present invention with an isocyanate substance, preferably the isocyanate substance obtained by a process of the pre- sent invention. According to a further embodiment, the present invention relates to the use of the polyol compo- sition according to the present invention or a polyol composition obtained or obtainable accord- ing to the process as disclosed above for the preparation of polyurethanes or polyisocyanu- rates. The present invention further relates to a process for preparing a polyurethane material by re- acting the polyol substance obtained by the process according to the present invention with an isocyanate substance, preferably the isocyanate substance obtained by a process of the pre- sent invention. Furthermore, the invention relates to a process for producing an isocyanate substance from an amine substance obtained by a process according to the present invention. The advantages and / or features described in connection with the process for recovering an amine substance also apply for the process for producing an isocyanate substance. Preferably, the amine substance resulting from the recovery process is fed into a purification sec- tion of an amine producing plant, an amine storage tank or an isocyanate producing plant, for example in the phosgenation section of an isocyanate production plant. For the use of the amine substance in the isocyanate production, the amine substance needs to be essentially free of polyol substance, residual metals and silicon compounds. Preferably the amine substance is phosgenated so that an isocyanate substance is formed. For example TDA may be phosgenated to prepare TDI or MDA may be phosgenated to prepare MDI. Furthermore, pMDA may be phosgenated to prepare pMDI and NDA may be phosgenated to prepare NDI. Suitable conditions for the phosgenation are in principle known to the person skilled in the art. According to a further embodiment, the present invention therefore is also directed to the pro- cess as disclosed above, wherein the process further comprises step e) e) conversion of the amine component to obtain an isocyanate composition. In the context of the present invention, the term “isocyanate composition” encompasses all iso- cyanates known to the person skilled in the art in connection with polyurethane chemistry, such as, in particular, toluene diisocyanate (TDI; prepared from toluene diamine, TDA) or the di- and polyisocyanates of the diphenylmethane series (MDI; prepared from the di- and polyamines of the diphenylmethane series, MDA). The expression "isocyanate composition" also encompasses embodiments in which two or more different isocyanates (e.g. mixtures of MDI and TDI) have been used in the preparation of the polyurethane material. This also applies within one isocyanate class (that is to say, for example, also applies to various MDI types). Also further isocyanates such as hexamethylene diisocyanate (HDI) and its oligomers or naphthylene diisocyanate (NDI) may be present. The totality of all isocyanates used in the preparation of the polyurethane material is referred to as the isocyanate composition (of the polyurethane material). The isocyanate com- position comprises at least one isocyanate. The conversion according to step (e) may for example be achieved by phosgenation or also by phosgene-free conversion. Suitable processes are for example liquid phosgenation, gasphase phosgenation or gas-liquid phosgenation or a phosgenation via salt or a phosgene-free conver- sion for example carbamate cleavage. Suitable conditions for the phosgenation are in principle known to the person skilled in the art and are for example disclosed in Ullmann’s Encyclopedia of Industrial Chemistry, 7thed. Vol.20, 2012, p.63-82, WO 99 / 54289 A, WO 2004 / 056756 A (liquid phosgenation); Ullmann’s Encyclopedia of Industrial Chemistry, 4thed. Vol.13, 2012, p. 353, DE 25870847 A, EP 1532107 A, EP 0570799 A EP 0289840 A (gasphase phosgenation); or EP 2044009 A1, WO 2013 / 060836 A, WO 2013 / 079517 A (gas-liquid phosgenation). An ex- ample of gas-liquid phosgenation process is 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 phosgene-free conversion are dis- closed in WO2018 / 185168 and EP 3250622 B1. Preferably, the phosgenation comprises admixing a solvent to the amine component and stir- ring, more preferably at a temperature in the range of from 50 to 180 °C, more preferably in the range of from 70 to 140 °C, more preferably in the range of from 80 to 120 °C, obtaining a poly- amine mixture; and bringing the polyamine mixture in contact with phosgene in a reactor and heating the obtained mixture to a temperature in the range of from 90 to 140 °C, more prefera- bly in the range of from 110 to 130 °C, obtaining a mixture comprising one or more polyisocya- nates. The present invention is also directed to the isocyanate composition obtained or obtainable ac- cording to the process as disclosed above. Furthermore, the present invention is directed to the use of the isocyanate composition according to the present invention or the isocyanate compo- sition obtained or obtainable according to the process according to the present invention for the preparation of polyurethanes or polyisocyanurates. For example TDI or MDI produced accord- ing to the present invention can be used as isocyanate substance to produce polyurethane foam by reacting it with a polyol obtained according to the present invention or any other suited polyol component. In embodiments, in which the recycled amine substance obtained by the process according to the present invention can be phosgenated together with virgin MDA or TDA to achieve virgin like isocyanates which can be utilized to produce polyurethane foams. The produced polyurethane material can in any suitable polyurethane application, preferably in the same application. The polyurethane material can for example be used in mattresses, furniture parts or car seats (TDI) or in appliance or construction applications (primarily pMDI) Further embodiments of the present invention can be found in the claims and the examples. It will be appreciated that the features of the subject matter / processes / uses according to the invention that are mentioned above and elucidated below are usable not only in the combination specified in each case but also in other combinations without departing from the scope of the invention. For example, the combination of a preferred feature with a particularly preferred feature or of a feature not characterized further with a particularly preferred feature etc. is thus also encompassed im-plicitly even if this combination is not mentioned explicitly. Illustrative embodiments of the present invention are listed below, but these do not restrict the present invention. In particular, the present invention also encompasses those embodiments which result from the dependency references and hence combinations specified hereinafter. 1. A process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1) b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a), wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). 2. The process according to embodiment 1, wherein the amine (A1) is prepared in the process itself and supplied by at least proportional recycling of at least one of the amine-containing components occurring in the process. 3. A process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1) b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a), wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1) and wherein the amine (A1) is prepared in the process itself and supplied by at least pro- portional recycling of at least one of the amine-containing components occurring in the process. 4. The process according to any one of embodiments 1 to 3, wherein the depolymerization according to step b) is carried out by a method selected from hydrolysis or hydroglycolysis. 5. The process according to any one of embodiments 1 to 4, wherein the process further com- prises a step c) c) removal of particulate solids from the reaction mixture. 6. The process according embodiment 5, wherein the process further comprises a step d) d) separation of the amine component and the polyol components. A process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1), b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a) by a method selected from hydrolysis or hydroglycolysis, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1), c) removal of particulate solids from the reaction mixture, d) separation of the amine component and the polyol components. A process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1) b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a) by a method selected from hydrolysis or hydroglycolysis, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). Polyol composition obtained or obtainable according to the process of any one of embodi- ments 1 to 8. Polyol composition obtained or obtainable according to the process for recycling of polyu- rethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1) b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a), wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). Polyol composition obtained or obtainable according to the process for recycling of polyu- rethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1), b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a) by a method selected from hydrolysis or hydroglycolysis, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1), c) removal of particulate solids from the reaction mixture, d) separation of the amine component and the polyol components. Polyol composition obtained or obtainable according to the process for recycling of polyu- rethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1) b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a) by a method selected from hydrolysis or hydroglycolysis, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1). Use of the polyol composition according to any one of embodiments 9 to 12 or a polyol composition obtained or obtainable according to the process of any one of embodiments 1 to 8 for the preparation of polyurethanes or polyisocyanurates. The process according to any one of embodiments 6 or 7, wherein the process further com- prises step e) e) conversion of the amine component to obtain an isocyanate component. A process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1), b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a) by a method selected from hydrolysis or hydroglycolysis, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1), c) removal of particulate solids from the reaction mixture, d) separation of the amine component and the polyol components, e) conversion of the amine component to obtain an isocyanate component. Isocyanate composition obtained or obtainable according to the process according to em- bodiment 14 or 15. Isocyanate composition obtained or obtainable according to the process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1), b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a) by a method selected from hydrolysis or hydroglycolysis, wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1), c) removal of particulate solids from the reaction mixture, d) separation of the amine component and the polyol components, e) conversion of the amine component to obtain an isocyanate component. 18. Use of the isocyanate composition according to embodiment 16 or 17 or an isocyanate composition obtained or obtainable according to the process according to embodiment 14 or 15 for the preparation of polyurethanes or polyisocyanurates. 19. A process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1), b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a), wherein the depolymerization is carried out in the presence of amine (A1) as catalytic ac- tive component and amine (A1) is the complementary amine to isocyanate (I1), wherein amine (A1) is supplied by at least proportional recycling of at least one of the amine-containing components occurring in the process. 20. The process according to embodiment 19, wherein the amine (A1) is prepared in the pro- cess itself. 21. The process according to embodiment 19 or 20, wherein at least one of the amine-con- taining streams formed during the reaction or work-up is completely or in parts recycled in the reaction stage to introduce the amine as a catalyst. 22. The process according to any one of embodiments 19 to 21, where an additional protic solvent is added to the reaction mixture in step b). 23. The process according to any one of embodiments 19 to 22, wherein the depolymeriza- tion according to step b) is carried out by a method selected from hydrolysis or hydrogly- colysis. 24 The process according to any one of embodiments 19 to 23, wherein the material is alco- holized by contacting the polyurethane material with an alcoholizing substance, wherein water is added in an amount so that a water content of a resulting mixture is from about 0.2 eq. to about 30 eq. water. 25. The process according to any one of embodiments 19 to 24, wherein the process further comprises a step c) c) removal of particulate solids from the reaction mixture. 26. The process according embodiment 25, wherein the process further comprises a step d) d) separation of the amine component and the polyol components. 27. Polyol composition obtained or obtainable according to the process of any one of embodi- ments 19 to 26. 28. Use of the polyol composition according to embodiment 27 or a polyol composition ob- tained or obtainable according to the process of any one of embodiments 19 to 26 for the preparation of polyurethanes or polyisocyanurates. 29. The process according to embodiment 26, wherein the process further comprises step e) e) conversion of the amine component to obtain an isocyanate component. 30. Isocyanate composition obtained or obtainable according to the process according to em- bodiment 29. 31. Use of the isocyanate composition according to embodiment 30 or an isocyanate compo- sition ob-tained or obtainable according to the process according to embodiment 29 for the preparation of polyurethanes or polyisocyanurates. The present invention can be further explained and illustrated on the basis of the following ex- amples. However, it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention in any way. Brief description of the figures: Figure 1a shows the IR analyses after phase separation for example 1. As references a model foam and pure 2,4-TDA was used. Figure 1b shows the ATR analyses of the amine phase of example 1. No urea vibration could be detected. References in green (TDI-urea) and blue (2,4-TDA). The symmetric and asymmetric N-C-N stretching vibration at 1553 cm^-1 could not be detected after the hydroglycolysis process (red curve). Figure 2 shows the pressure / temperature curve of the autocatalytic solvolysis reaction for ex- ample 1. Figure 2a show the pressure / temperature curve of the autocatalytic solvolysis reaction for ex- ample 2 Figure 2b shows the pressure / temperature curve of the autocatalytic solvolysis reaction foe example 4. Figure 2c shows the pressure / temperature curve during autocatalytic hydrolysis of PU rigid foam for example 6. Figure 3a shows the ATR analysis of water-free upper phase for example 2: The IR spectrum of the sample essentially shows the bands for polypropylene glycol and 2,4- diaminotoluene. In addition, a very weak, broad band (1750 - 1700 cm-1) can be seen, which can originate from several C=O groups which overlap (e.g. acid, ester, urethane, etc.). A NH band at ~1550 cm-1 is not observed in the spectrum. Figure 3b shows the ATR analysis of water-free bottom phase for example 2: Sample shows essentially the bands for diethylene glycol and 2,4-diaminotoluene. Compared to the reference sample from DEG / TDA, no additional bands show up in the C=O region. Figure 4a shows the IR analysis after phase separation for example 3. Samples were diluted in DMSO. No urethane vibration could be detected after the hydroglycolysis reaction. Thereof full conversion could be assumed. Figure 4b shows the GPC-analysis of amine phase for example 3. No polyol could be detected. Figure 5 shows the ATR analysis of water-free bottom phase for example 4: Sample shows essentially the bands for diethylene glycol and 2,4-diaminotoluene. Compared to the reference sample from DEG / TDA, no additional bands show up in the C=O region. Figure 6a shows the process scheme of batch column as used for example 5. This setup was used to distill DEG and TDA of the bottom phase. Figure 6b shows the pressure / temperature curve in dependence to distillation time for example 5. Figure 7 shows a general process scheme for the hydrolysis of a PU-rigid foam. Examples I. Explanation of terms PU flexible foam consists of TDI (Toluenediisocyanate, isomers: 2,4 TDI and 2,6 TDI) and long chain Polyether polyols (Polyol 1). The foam contains foaming catalysts, a blowing agent and stabilizers as well. End of life (EoL foam) flexible PU foam was sorted by a spectroscopic method to minimize the content of high resilience (HR) polyols and Styrene acrylonitrile resin (SAN) polymer particles. PU rigid foam consists of polymeric isocyanate (pMDI) and polyether and / or polyester pol- yols. The foam contains foaming catalysts, blowing agents and stabilizers as well. II. Materials used Polyol 1: is a trifunctional polyether polyol with a OH-number of 48 mg / g and predomi- nantly secondary hydroxyl groups. Polyol 2: polyester-polyols containing predominately on terephthalic acid, fatty acids, di or trifunctional glycolsand short chain polyether polyols (M = 350 g / mol). The OH number is about 245 mg / g. Polyol 3: Polyester polyol based phthalic acid, diethylene glycol andmonoethylene glycol, The OH number is about 240 mg / g. Isocyanate 1: TDI (Toluenediisocyanate, isomers: 2,4 TDI and 2,6 TDI) Isocyanate 2 (pMDI-1) is polymeric isocyanate with a typical NCO content of 31.5 g / 100g and a viscosity at 25°C of about 550 mPas. It is available as a commercial product from BASF. III. Analytical methods: 1. IR-spectroscopy: IR spectroscopy was carried out to determine the conversion of the remonomerization reaction. Spectrometer set up: Nicolet 6700 – FT-IR spectrometer (Thermo Fisher Scientific) Number of scans: 32 Resolution: 2 cm-1Detector: DTGS KBr Spectral range: 400 cm-1– 4000 cm-11.1 Hydroglycolysis (Alcohol, preferably diethylene glycol, water): The area ratio of the Ure- thane vibration (1700 cm-1to 1750 cm-1) before and after the reaction was correlated to the conversion. 1.2 Hydrolysis (water): The area ratio of the Urethane vibration (1700 cm-1to 1750 cm-1) be- fore and after the reaction was correlated to the conversion. Before the IR analysis water was completely removed. 2. ATR-analysis: ATR spectroscopy was carried out to check the absence of the urea vibra- tion after hydroglycolysis or hydrolysis process 3. High performance liquid-chromatography (HPLC): HPLC analyses was carried out to de- termine 2,4-, 2,6-TDA and 2,2-, 2,4-, 4,4-MDA. HPLC-setup: Agilent Technologies “1200 Series” Column: Fluofix (5 µm, 250 x 4.6 mm) Detection: 205 nm Temperature: 25°C Injection volume: 10 µL Mobile phase: (A)1000 mL water + 1 ml H3PO4, (B) 950 mL Acetonitrile + 50 mL water + 1 mL H3PO44. GC-analysis: Quantification of 2,2-, 2,4-, 4,4-MDA, 3-ring MDA, 4-ring MDA, and 5-ring MDA. The detailed description of the GC method is listed below: GC-setup: Agilent 7890A Column: DB-5HT (30m x 0,32mm x 0,1µm) Temperature program: 80°C-5min-6°C / min-370°C-30min Injection temperature: 340°C Injection volume: 1 µL Detector temperature: 340°C Carrier gas : Hydrogen (Constant Pressure 10psi) Split ratio: 15:1 5. Quantitive1H-NMR analyses: Quantification of TDA NMR-setup: Bruker AV401 Solvent: Deuterated Dimethylsulfone IV Examples 1. Model foam: 1.1 Soft / flexible foam (MF1) Flexible foam: Hydroglycolysis of foam synthesized from isocyanate 1 (2,4 TDI and 2,6 TDI), polyols and additives like catalysts, surfactants, blowing agents required for foaming (30.9 wt.-% TDI and 61.9 wt.-% polyol 1). Surfactants: Silicone oils Blowing agents: Water, CO2Catalysts: Usually tertiary amines) 1.2 Rigid foams (MF2) PIR-construction foam: Hydrolysis of a foam synthesized from isocyanate 2, polyols and different additives like e. g. catalysts, surfactants, blowing agents required for foaming (71.4 wt.-% M50S; 18.4 wt.-% polyols primarily polyol 2 and 3 containing predominately aromatic dicarboxylic acids, like phthalic acid and terephthalic acid and glycols as well as short-chain polyether polyols) Surfactants: Silicone oils Blowing agents: Water, Cyclopentane Catalysts: Usually tertiary amines) and potassium salts 2. EoL / Industrial production waste 2.1 Flexible foam (EF1) Foam based on TDI and polyols similar to polyol 1 Additives and impurities: Foaming catalysts, stabilizers, SAN-polymer particles, HR-polyol, metals, inorganic salts (e g. CaCO3) PU rigid foam (EF2) Foam based on isocyanate 3 and a mixture of polyols similar to polyol 2 and 3. Additives and impurities: Foaming catalysts, stabilizers, metals, inorganic salts Examples Example 1: Autocatalytical hydroglycolysis of flexible foam – model foam (MF1) 15 g of the model foam was cooled with liquid nitrogen and milled using a coffee grinder. Afterwards the foam, 15 g diethylene glycol (DEG), 15 g water and 5 g 2,4-TDA were charged to a stirred autoclave. Before the reaction mixture was heated to 200 °C, the reactor was closed and its contents purged three times with nitrogen to ensure a non-oxidizing atmosphere The hydroglycolysis reaction was done at 200 °C and approximately 15 bar (depending on the vapor pressure of the mixture DEG / water / TDA) for 4 h. After the reaction the mixture was cooled down to room temperature and filtrated to remove inorganic impu- rities. The phase separation of the filtrate was carried at 80°C. The upper phase (Polyol rich phase) and the lower phase (Polyol poor phase) was analyzed by HPLC to determine the TDA content. The TDA yield was about 99 % due to the HPLC analysis results (utilized TDA as catalyst was subtracted). The conversion level was higher as > 99 % due to area ratio of the urethane vibration. Example 2: Autocatalytical hydroglycolysis of flexible foam with higher mass load (EF1) For the solvolysis reaction a model foam (177.05 g), DEG (177.54 g), Water (180.23 g) and both of TDA isomers (2,6-TDA, 11.053 g, purity of 97% and 2,4-TDA, 44.08 g, purity of 98%) were put into the pressure reactor. Before the reaction mixture was heated to 200 °C, the reactor was closed and its contents purged three times with nitrogen to ensure a non- oxidizing atmosphere. The anchor stirrer was switched on during heating and set to 200 rpm. As soon as the temperature in the decomposition mixture reached the 200°C, the re- action time started, which was set to 4 hours. Temperature and pressure curves during the trials were recorded and are presented in figure 2a. After 4 hours, the mixture was cooled to room temperature and was collected for further processing. a) Filtration First, the homogeneous reaction mixture was filtrated under pressure (3 bar) at 80°C (overnight) using a depth filter with 15 µm pore size. At this step 4.2 wt.-% of solids related to the foam weight were separated. b) Phase separation The filtrated mixture was then transferred to the separating funnel and the phases were separated at 80°C. The ratio after separation was: 28 wt.-% for the upper phase and 72 wt.-% for the lower phase. After hydroglycolysis the TDA yield was 115% according to the HPLC analysis and 102% according to the quantitative NMR analysis (considering and subtracting TDA added as a catalyst). Theoretical TDA content in the lab foam: 22.96 % TDA content in upper and lower phase: Upper phase Lower phase HPLC 15.9% 18.8% Quant. NMR 15% 17.8% 3.3 Example 3: Autocatalytical hydroglycolysis of flexible foam – EoL foam (EF1) 15 g of the model foam was cooled with liquid nitrogen and milled using a coffee grinder. Afterwards the foam 15 g diethylene glycol (DEG), 15 g water and 5 g 2,4-TDA were charged to a stirred autoclave. Before the reaction mixture was heated to 200 °C, the reactor was closed and its contents purged three times with nitrogen to ensure a non-oxidizing atmosphere. The hydroglycolysis reaction was carried out at 200 °C and approximately 15 bar (depending on the vapor pressure of the mixture DEG / water / TDA) for 4 h. After the reaction the mixture was cooled down to room temperature and filtrated to remove inorganic impurities. The phase separation of the filtrate was carried out at 80°C. The upper phase (polyol rich phase) and the lower phase (polyol poor phase) were analyzed using HPLC to determine the TDA content. The trial was repeated with 180 g foam. The TDA yield in both trials was about 95 % according to the HPLC analysis results (utilized TDA as catalyst was subtracted and a TDI-content in the EoL foam of 30.9 wt.-% was assumed). The conversion was > 99 % according to the area ratio of the urethane vibration. GPC analysis was carried out to qualify the existence of polyether polyol in the lower phase (amine rich phase). No polyether polyol peak was detected. 3.4 Example 4: Autocatalytic hydroglycolysis of flexible EoL foam with higher mass load (EF1) For the decomposition reaction an end-of-life foam (908 g), DEG (907g), Water (909 g) and 2,4-TDA isomer (278 g, purity of 98%) were put into the pressure reactor. Before the reac- tion mixture was heated to 200 °C, the reactor was closed and its contents purged three times with nitrogen to ensure a non-oxidizing atmosphere. The anchor stirrer was switched on during heating and set to 200 rpm. As soon as the temperature in the decomposition mixture reached 200°C, the reaction time started, which was set to 4 hours. Temperature and pressure curves during the trials were recorded and are presented in figure 2b. After 4 hours, the mixture was cooled to room temperature and was collected for further processing. a) Filtration First, the reaction mixture was filtrated under pressure (3 bar) at 80°C (overnight) using a depth filter with 15 µm pore size. At this step 7 wt.-% of solids related to the foam weight were separated. b) Phase separation The filtrated mixture was then transferred to the separating funnel and the phases were separated at 80°C. The ratio after separation was: 28 wt.-% for the upper phase and 72 wt.- % for the lower phase. Table 1: Composition of upper and lower phase. The upper phase can be defined as amine poor phase whereas the bottom phase has a higher TDA content. Upper phase wt.-% Lower phase TDA 14 16 DEG 9 42 Water 7 40 Polyol 69.4 Not detectable via GPC Comparing the ATR spectra no band at ca.1725 cm-1(C=O vibration) and at ca.1550 cm-1(N-H vibration) could be detected. 3.5 Example 5: Batch distillation of bottom phase- Recovery of DEG and TDA The bottom phase was distilled in a lab scale batch distillation column to recover DEG and TDA. The schematic setup of the distillation column is shown in figure 6a: The operating data during distillation in a lab distillation column are presented in fig.6b. During the distillation, several fractions were collected and analyzed. The composition of the fractions are listed in table2. Table 2: Overview of the collected distilled fractions. Water wt.-% DEG wt.-% TDA wt.-% Fr.1 99 0 0 Fr.2 99 1 0 Fr.3 4 95 0 Fr. 4100 0Fr.5 100 0 Fr. 6100 0Fr.7 100 0 Fr. 8100 0Fr.9 100 0 Fr.10101 0Fr.11 98 2 Fr.12 18 77 Fr.13 0 99 Fr.143 97Fr.15 1 98 The distillation was stopped at a low filling level of the reservoir vessel, to prevent break- down of, the heating via natural circulation. The following tables 3 and 4 summarize the mass balances for DEG and TDA as well as the sump composition. Table 3: Mass balance of DEG and TDA after batch distillation. Initial weight of amine phase: (Feed) 1540 g Weight of collected fractions: 1037 g TDA balance 95 % (250 g in feed, 238 g found) DEG balance 100 % (645 g in feed, 645 g found) Sump after distillation 91 g Weight of amine phase in distillation elements, col- 74 g lected after cleaning: Weight of amine phase in the cool trap: 180 g Table 4: Sump composition after distillation Component wt.-% TDA 58 DEG 0.5 Heavy boilers 41 3.6 Example 6:Autocatalytically hydrolysis of PU rigid foam– (MF2) 4 g of the milled model foam, 40 g water and 1 g pMDA were charged to a stirred autoclave. The hydrolysis reaction was done at 250 °C and approximately 35 bar (depending on the vapor pressure of the mixture water / pMDA) for 4 h. The pMDA yield was about 85 % ac- cording to GC analysis results (utilized pMDA as catalyst was subtracted). 3.7 Example 7: Neutralization and phase separation after autocatalytic hydrolysis – model system Model system: The model system is a mixture of pMDA, Terephthalic acid (TA), Phthalic acid (PA), DEG, MEG, glycerol. The composition of the model system is similar to a representative composition of polyol 2 and 3. a) Neutralization: For the neutralization 55 g pMDA, 3 g TA, 3 g PA, 6 g DEG 0.3 g MEG, 0.4 g glycerol were mixed together as model system. To the model system 150 g water and 4 g NaOH (solid) was dosed. After 10 min stirring at 80°C all solid compounds were dis- solved. The solubility indicates the sodium salt of the acids have been formed b) Phase separation: 250 g chlorobenzene (MCB) were added to the aqueous neutralized model system. The mixture was stirred for 30 min at 80°C. Afterwards the two phases were separated in a separating funnel. The water content of the MCB phase was analyzed via Karl- Fischer-Titration.0.2 wt.-% water could be detected in the lower phase. The chloro- benzene of the lower phase was totally evaporated. An elementary analysis of the residue was carried out to check the absence of sodium salts and glycols in the lower phase. The sodium content was lower than 30 ppm and the oxygen content was lower than 0.5 wt.-%. Table 5: Results from the elementary analysis of the lower phase after MCB removal. Element Mass fraction / wt.-% Carbon (C) 78.8 Oxygen (O)_balanced <0.5 Nitrogen (N) 14.4 Hydrogen (H) 7.0 Sodium(Na) <0.003 3.8. Process scheme – flexible foam hydroglycolysis Hydroglycolysis: Stirred tank reactor (20-100 m³), temperature 170-250°C and pressure 1-50 bar, Alcohol / foam-mas ratio 1:1 to10:1, water / foam ratio 1:1 until 10:1 and catalyst (TDA) (5-35 wt.-% with respect to the foam mass) Filtration: Preferably, the solid-liquid separation unit is a filtration unit or a centrifuge, more preferably a filtration unit, more preferably a filter, more preferably a pocket filter, a bag filter, a membrane filter, a candle filter, an agitated pressure filter, a vacuum belt filter, a frame & plate filter, or a nutsche filter (Source: 220263 EP01) 3.9 Process scheme – PU-rigid foam- Hydrolysis A general process scheme is shown in figure 7. Hydrolysis: Stirred tank reactor (20-50 m³), Temperature 170-250°C and Pressure 1-40 bar, foam / water mass ratio: 1 :11 to 1:10, pMDA as catalyst (5-20 wt.-% with respect to foam) Filtration: Preferably, the solid-liquid separation unit is a filtration unit or a centrifuge, more preferably a filtration unit, more preferably a filter, more preferably a pocket filter, a bag filter, a membrane filter, a candle filter, an agitated pressure filter, a vacuum belt filter, a frame & plate filter, or a nutsche filter Phase separation: Extraction aid can be any organic solvent which has a mixing gap with water Neutralization step: As neutralization agent any base which has a higher basicity as ani- line can be applicated. The neutralization is usually carried out in a stirred tank reactor at 80°C. Preferably, the neutralization unit is a stirred tank reactor. Polyester-fragments-work up: Re-polymerization of Polyester-fragments by polyconde- sation under vacuum, distillative removal of water in presence of a Bronsted or Lewis acid and if necessary in presence of further added glycols or acids to guarantee a equimolar ratio between OH- and COOH-groups. Usually a stirred tank reactor is used. pMDA- work up: pMDA-work up and phosgenation

[0002] Literature cited CN106700126 US20010027246 EP 1142945 A2 CN1275587 WO2022 / 063764 "Kunststoffhandbuch [Plastics handbook], volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, chapter 3.1, 3.2 and 3.3.2 WO 2006 / 034800 EP 0090444 WO 2005 / 090440 EP22178796.3 EP22178797.1 Ullmann’s Encyclopedia of Industrial Chemistry, 7thed. Vol.20, 2012, p.63-82 WO 99 / 54289 A, WO 2004 / 056756 A Ullmann’s Encyclopedia of Industrial Chemistry, 4thed. Vol.13, 2012, p.353 DE 25870847 A EP 1532107 A EP 0570799 A EP 0289840 A EP 2044009 A1 WO 2013 / 060836 A WO 2013 / 079517 A WO 2022 / 106716 EP 1761483 B1, EP 2079684 B1, EP 2188247 B1, EP 2408738 B1 EP 2539314 B1 WO2018 / 185168 EP 3250622 B1

Claims

Claims 1. A process for recycling of polyurethane or polyisocyanurate containing waste comprising the steps of a) providing a composition comprising a comminuted polyurethane or polyisocyanurate foam which is obtained from isocyanate composition (IC) comprising isocyanate (I1), b) depolymerization of the comminuted polyurethane or polyisocyanurate provided in step a), wherein the depolymerization is carried out in the presence of amine (A1) as catalytic active component and amine (A1) is the complementary amine to isocyanate (I1), wherein amine (A1) is supplied by at least proportional recycling of at least one of the amine-containing components occurring in the process.

2. The process according to claim 1, wherein the amine (A1) is prepared in the process itself.

3. The process according to claim 1 or 2, wherein at least one of the amine-containing streams formed during the reaction or work-up is completely or in parts recycled in the reaction stage to introduce the amine as a catalyst.

4. The process according to any one of claims 1 to 3, where an additional protic solvent is added to the reaction mixture in step b).

5. The process according to any one of claims 1 to 4, wherein the depolymerization according to step b) is carried out by a method selected from hydrolysis or hydroglycolysis. 6 The process according to any one of claims 1 to 5, wherein the material is alcoholized by contacting the polyurethane material with an alcoholizing substance, wherein water is added in an amount so that a water content of a resulting mixture is from about 0.2 eq. to about 30 eq. water.

7. The process according to any one of claims 1 to 6, wherein the process further comprises a step c)c) removal of particulate solids from the reaction mixture.

8. The process according claim 7, wherein the process further comprises a step d) d) separation of the amine component and the polyol components.

9. Polyol composition obtained or obtainable according to the process of any one of claims 1 to 8.

10. Use of the polyol composition according to claim 9 or a polyol composition obtained or ob- tainable according to the process of any one of claims 1 to 8 for the preparation of polyu- rethanes or polyisocyanurates.

11. The process according to claim 8, wherein the process further comprises step e) e) conversion of the amine component to obtain an isocyanate component.

12. Isocyanate composition obtained or obtainable according to the process according to claim 11.

13. Use of the isocyanate composition according to claim 12 or an isocyanate composition ob- tained or obtainable according to the process according to claim 11 for the preparation of polyurethanes or polyisocyanurates.

Images