Process for recycling polyurethane foams

Abstract

The present invention is directed to a process for recycling waste polyurethane material at least comprising the steps of providing a waste polyurethane material (W); separating of the polyurethane material (PU1) and further compo- nents of the waste polyurethane material (W); sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2); subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2); sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3); depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M1); and the separation of the components pf mixture (M1). Furthermore, the present invention is directed to the polyol composition obtained or obtainable according to the process of the invention and the use thereof for the preparation of polyurethanes and the isocyanate composition obtained or obtainable according to the process of the present invention and the use thereof for the preparation of polyurethanes.

Description

[0001] Process for recycling polyurethane foams

[0002] Description

[0003] The present invention is directed to a process for recycling waste polyurethane material at least comprising the steps of providing a waste polyurethane material (W); separating of the polyurethane material (PU1) and further components of the waste polyurethane material (W); sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2); subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2); sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3); depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M 1 ); and the separation of the components of mixture (M 1 ). Furthermore, the present invention is directed to the polyol composition obtained or obtainable according to the process of the invention and the use thereof for the preparation of polyurethanes and the isocyanate composition obtained or obtainable according to the process of the present invention and the use thereof for the preparation of polyurethanes.

[0004] Polyurethanes, hereinafter also referred to as PU, are plastics that result from the polyaddition reaction of dialcohols or polyols with polyisocyanates. Diols and diisocyanates result in linear polyurethanes; crosslinked polyurethanes can be produced by reacting polyisocyanate mixtures with polyol mixtures. The properties of PU can be varied within a wide range. Depending on the degree of crosslinking and / or the isocyanate or OH component used, thermosets, thermoplastics or elastomers are obtained. However, polyurethanes are also used as molding compositions for compression molding, as casting resins (isocyanate resins), as (textile) elastic fibers, polyurethane varnishes and as polyurethane adhesives. It is also very easy to produce foams from polyurethane.

[0005] Flexible PU foams are used for a wide variety of purposes, especially as upholstery material, for example for furniture and car seats, as mattress foam, as carpet backing material, for textile lamination, as cleaning sponge or as filter material.

[0006] At the end of the use phase of the products containing PU material, they are usually disposed of, i.e. stored in landfills or incinerated in waste incineration plants. It has not yet been possible to date to carry out material use in an economically successful manner, i.e. it has not yet been possible to recover the polyols or isocyanates used from the PU materials in an economical yield.

[0007] The recycling of waste streams represents an essential building block for achieving greater sustainability of existing value chains. In material cycles of plastics, remonomerizations as recycling techniques are those with the greatest circularity. Processes are disclosed in the state of the art for remonomerizing polyurethane foams after automated (overbelt) NIR sorting. However, the production of high quality polyurethanes, for example foams, from polyols and isocyanates obtained in recycling processes is difficult with only one sorting step as described in the prior art. According to known processes, large input material streams have to be transported, shredded and sorted out with automated NIR technology. Due to large volume, many false throws result during sorting which in turn result in poor yield and many impurities which in turn lead to poor quality of the end product.

[0008] There is a need to develop processing techniques to recover polyurethane materials from plastic waste. The recycling process should reduce both the waste of material and the carbon footprint. Further, it should be an economical and energy efficient process delivering valuable materials which comprise high technical features.

[0009] This object has been achieved by a process for recycling waste polyurethane material at least comprising the steps of

[0010] (I) providing a waste polyurethane material (W);

[0011] (II) separating of the polyurethane material (PU1) and further components of the waste polyurethane material (W);

[0012] (ill) sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2);

[0013] (iv) subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2);

[0014] (v) sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3);

[0015] (vi) depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M1 );

[0016] (vii) separation of the components of mixture (M 1 ).

[0017] It has been surprisingly found that it is possible to improve the product quality and increase process efficiency in a polyurethane recycling process through the prior pretreatment and pre-selection / pre-sorting of waste materials according to the process of the present invention.

[0018] According to the present invention, the waste material is subjected to several sorting steps. It has been found that the combination of the specific steps allows to remonomerize the polyurethane material and obtain the monomers in high quality which allows to prepare materials such as polyurethane foams with high quality. It has been found that the process is particularly suitable for the recycling and remonomerization of polyurethane foams. Thus, according to the present invention, the waste polyurethane material (W) preferably is a waste polyurethane foam, in particular a waste flexible polyurethane foam.

[0019] The process according to the present invention comprises steps (i) to (vii). According to the present invention, the end-of-life (EoL) materials, such as for example mattresses are "processed" to ensure high quality input stream. The process of the present invention allows to remove impurities contained in the material, in particular the foam, for example in mattress, such as for example metals, other substances such as for example wood, or foreign polymers which cannot be detected using the processes according to the state of the art.

[0020] After removal of the impurities, the remonomerization can be carried out more effectively and with better results.

[0021] 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 polyamines which may readily be converted to polyisocyanates.

[0022] Polyurethanes usually are prepared form an isocyanate component comprising at least one isocyanate and a polyol component comprising at least one polyol.

[0023] The process according to the present invention comprises steps (i), to (vii) 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.

[0024] 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 (i) and (ii), or between steps (ii) and (iii), or between steps (iii) and (iv), or between steps (iv) and (v), or between steps (v) and (vi), or between steps (vi) and (vii). In the context of the present invention it is also possible that step (ii) is carried out directly after step (i). It is also possible that step (iii) is carried out directly after step (ii), and / or that step (iv) is carried out directly after step (iii), and / or that step (v) is carried out directly after step (iv), and / or that step (vi) is carried out directly after step (v), and / or that step (vii) is carried out directly after step (vi).

[0025] According to step (i), a waste polyurethane material (W) is provided.

[0026] The polyurethane materials used in the present invention are preferably obtained from items produced from polyurethane materials at a time after use for the purpose for which they were manufactured or polyurethane materials waste from production processes. Herein, the term "polyurethane material waste” includes end-of-life polyurethane materials and production rejects of PU materials or waste generated through further processing of PU materials. In this context, the term "spent polyurethane material” denotes an item produced from a polyurethane material at a time when it has already been used for the purpose for which it was manufactured. "Production rejects of polyurethane materials" denotes polyurethane material waste occurring in production processes of PU materials.

[0027] The polyurethane material may in particular be a polyurethane foam preferably is a flexible foam for upholstery material, for example for furniture and car seats, or a mattress foam.

[0028] Generally, polyurethane materials are produced by a reaction between a polyisocyanate component and a polyol component. Typically, further materials, in particular additives, such as 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 polymers.

[0029] The properties of the polyurethane materials might vary in broad ranges. They are influenced by the chemistry of polyisocyanate and polyol components used and the recipe applied in polymerisation. For example, the starting materials may influence the crosslinking density of the polymers in a three-dimensional network. Rigid polyurethane foams are typically obtained from monomers with a comparably low molecular weight and high functionality creating a highly crosslinked, dense network.

[0030] Industrially and consequently in large quantities, especially methylenedi(phenylisocyanate) (MDI) or its polymeric forms or tolylene 2,4 and 2,6-diisocy anate (TDI) are used as polyisocyanate components for the production of PU flexible foams. For a representative composition of these PU foams, see for example US 9,023,907 B2, WO 2015 / 121057 and WO 2013 / 139781.

[0031] 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 isocyanate groups, i.e. also diisocyanates.

[0032] Suitable polyisocyanate components used for the production of the polyurethanes may comprise any of the polyisocyanates known for the production of polyurethanes. These comprise the aliphatic, cycloaliphatic, and aromatic difunctional 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, the mixtures of monomeric diphenylmethane 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, hexamethylene diisocyanate (HDI) and its oligomers, naphthylene diisocyanate (NDI), and mixtures thereof. Preferably, tolulene 2,4- and / or 2,6-diisocynate (TDI) or a mixture thereof, monomeric diphenylmethane diisocyanates, and / or diphenylmethane diisocyanate homologs having a larger number of rings (polymer MDI), and mixtures of these. Other possible isocyanates are mentioned by way of example in "Kunststoffhandbuch [Plastics handbook], volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, chapter 3.2 and 3.3.2.

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

[0034] Common polyols used in huge quantities are, e.g., selected from the group consisting of polyether polyols, polyester polyols, polyetherester polyols and mixtures thereof.

[0035] 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-activity, 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.

[0036] 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 handbook], volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, chapter 3.1.

[0037] According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the polyurethane foams are selected from the group consisting of toluene diisocyanate (TDI) derived polyurethane foams hexamethylene diisocyanate (HDI) derived polyurethane foams, naphthylene diisocyanate (NDI) derived polyurethane foams, polymeric methylenedi(phenylisocyanate) (pMDI) derived polyurethane foams and methylenedi (phenylisocyanate) (MDI) derived polyurethane foams.

[0038] According to step (ii), the polyurethane material (PU1) and further components of the waste polyurethane material (W) are separated.

[0039] Suitable steps for separating the polyurethane material and further components are in principle known and include for example removal of foreign polymers such as removal of packaging / foils from transport, disassembling of waste products, such as for example removal of fabric cover, mattress protector, removal of solid parts, such as for example removing spring cores (metal) or wooden parts. According to the present invention, preferably solid parts such as metal parts or wooden parts are removed according to step (II) thus reducing the amount of comminuted material in the process. For example steel springs can be removed and recycled and wooden parts such as wooden frames can be removed and shredded into smaller pieces separately.

[0040] Separation according to step (II) may also include a pre-sorting using suitable methods such as for example visual I haptic appraisal, sorting by color, pore size distribution, elasticity or using spectroscopic method such as for example NIR methods.

[0041] The process according to the present invention further comprises step (ill) of sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2). Suitable methods such as for example spectroscopic methods are in principle known to the person skilled on the art. Furthermore, sorting can include further separation steps, such as for example removal of foam materials which include high amounts of additives or graft polyols.

[0042] The process may for example comprise sorting steps based on optical methods, for example based on NIR spectroscopy. Sorting based on optical methods may for example be used in the process to determine the graft polyol content of the polyurethane foam. Preferably, the process may also comprise steps to adjust the graft polyol content of a mixture in a predetermined range, for example separate foams with a graft polyol content of less than 5% by weight and foams with a graft polyol content of more than 5 %by weight or also foams with a graft polyol content in the range of from 5 to 10% by weight and foams with a graft polyol content of more than 10 %by weight.

[0043] Furthermore, sorting may be based on the content of additives such as for example flame retardants or the chemical nature of the isocyanates present in the polyurethane materials.

[0044] According to step (iv), the purified polyurethane material (PU2) is subjected to a mechanical treatment to give a comminuted polyurethane material (PU2).

[0045] In the context of the present invention, a "comminuted polyurethane material” or a "comminuted polyurethane foam” means the material is obtained from a material or foam and the comminuted polyurethane is for example used in shredded form, in the form of granules, flakes, as an agglomerate, or as a powder. The polyurethane materials and foams can be comminuted by conventional methods, for example by shredding, e.g. in a rotation mill or rotary mill at room temperature, to an average particle size of ordinarily less than 500 mm, for example to an average particle size in the range of from 50 to 500 mm, preferably to an average particle size of less than 50 mm, in particular less than 30 mm, or ground, e.g. by known cold grinding processes. According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the mechanical treatment according to step (iv) is selected from the group consisting of milling, beating, shredding, tearing and mixtures of two or more of these treatments.

[0046] According to step (v) the comminuted polyurethane material (PU2) is sorted and impurities are removed to give a purified comminuted polyurethane material (PU3).

[0047] Step (v) typically comprises further sorting e.g. by sieving or separation by rates of density, i.e. by air, a liquid or magnetically. Optionally, the fragments may also undergo processes to eliminate impurities, e.g. paper labels, metal parts or wooden parts. Suitable methods are in principle known to the person skilled in the art. Suitable are for example spectroscopic methods such as for example NIR spectroscopy.

[0048] The process according to the present invention further comprises step (vi) of depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M1).

[0049] 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 methylene phenylene amine and toluenediamines (TDA), in particular 2,4 toluenediamine or 2,6-toluenediamine, hexamethylene diamine (HDA), and naphthylene diamines (NDA). The commonly used polyols as described above preferably also can be re-isolated. Thus, the process preferably 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

[0050] Typically, the depolymerization results in polyol components and amine components.

[0051] After work-up, the polyol-containing phase may be used at least proportionally in new PU formulations. 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 proportionally as an isocyanate component in PU production.

[0052] Suitable methods for depolymerization are in principle known to the person skilled in the art. Preferably, the depolymerization is achieved by hydrolysis, acidolysis, alcoholysis, such as glycolysis, hydroalcoholysis such as hydroglycolysis, hydrogenation, hydroammonolysis, hydroaminolysis or by aminolysis according to the present invention. Preferably, depolymerization is achieved by glycolysis, hydroglycolysis or hydrolysis according to the present invention.

[0053] Depending on the method used for depolymerization, different products are obtained. Preferably, it is possible to recover both starting material components from the polyurethane. According to the present invention, the hydrolyzing step and the alcoholysing, ammonolysing or aminolysing step may be performed separately or may be combined. Typically, the amine corresponding to the isocyanate component used in the PU material is obtained by applying depolymerization processes comprising a hydrolysis step optionally together or after applying a e.g. alcoholysis, ammonolysis, aminolysis. But also the polyol component or monomer fragments of the polyol component can be separated. Usually, the depolymerization results in a mixture of components which might be separated using suitable separation techniques. The process of the present invention may also comprise further separation steps.

[0054] According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the depolymerization according to step (vi) is carried out by a method selected from hydrolysis, glycolysis, hydroammonolysis or hydroglycolysis.

[0055] 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 (vi). Preferably, the depolymerization is carried out without the addition of further catalyst. The resulting products of the depolymerization may be separated using suitable separation techniques which are in principle known to the person skilled in the art.

[0056] Also methods for depolymerization by glycolysis are in principle known. Preferably, glycolysis is carried out in the presence of a base. Therefore, according to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the glycolysis is carried out in the presence of a catalyst, for example alkali metal hydroxides such as potassium hydroxide, or amines.

[0057] Suitable methods for depolymerization by hydrogenation include the hydrogenation in the presence of a hydrogenation catalyst. Therefore, according to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the hydrogenation is carried out in the presence of a hydrogenation catalyst.

[0058] Another possibility is the depolymerization of the remaining polyurethane by hydrolysis with water in the presence of reusable organic nitrogen bases such as 1 -alkylimidazoles in combination with water as described in W02010 / 130652A2, or pyridine / water or the combination of nitrogen-containing ionic liquids and water to allow the hydrolysis at lower temperatures and shorter reaction times.

[0059] In particular for recovering an amine substance, it is beneficial if a polyurethane material is alcoholised 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 hydroalcoholising, i.e. , hydroalcoholysis, 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 and urea 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 cleavable bonds is equivalent to the amount of the isocyanate group content in the original polyurethane material.

[0060] Preferably, the depolymerization is carried out by hydroglycolysis according to the present invention.

[0061] 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 temperature in the range of from 170 to 250°C at a pressure in the range of from 1 to 50 bar.

[0062] After depolymerization according to step (vi), typically a mixture of reaction products is obtained.

[0063] Preferably, the process further comprises allowing the mixture to settle, wherein one or more phases are formed or the mixture could be extracted via an organic anhydrous solvent which is not or partially miscible with water. Further, in particular for recovering the components, the process comprises preferably a work-up which may comprise one or more of the following:

[0064] - filtration;

[0065] - centrifugation;

[0066] - decantation;

[0067] - extraction;

[0068] - distillation;

[0069] - full or partial evaporation of the phases in one or more evaporators;

[0070] - contacting the phases with an ion exchange material;

[0071] - contacting the phases with one or more adsorbents.

[0072] According to step (vii), the components of mixture (M1) are separated.

[0073] 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.

[0074] According to one aspect of the invention, solids may be removed from the mixture before or after the mixture is allowed to settle, preferably by one or more of the following: filtration, centrifugation, decantation. According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the process according to step (vii) further comprises step a) a) removal of particulate solids from the reaction mixture (M1).

[0075] 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 pressure filter, a vacuum belt filter, a frame & plate filter, or a nutsche filter.

[0076] For filtration, preferably a cascade of filters may be used.

[0077] In the alternative or additionally, centrifugation is a preferred solid-liquid-separation method.

[0078] 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, chromatography or distillation under reduced pressure. Preferably, the work up comprises several steps.

[0079] Preferably, the process comprises allowing the mixture to settle. According to the present invention, it is possible that one or more phases are formed and the components of the mixture may be separated by suitable separation steps. According to the present invention, it is for example possible to extract the mixture via an organic anhydrous solvent which is not or partially miscible with water.

[0080] According to a preferred embodiment, a phase separation is performed after the mixture has settled. Preferably, the phase separation is performed in a phase separation device. For improved phase separation, it can be beneficial to remove water included in the mixture, e.g., by flash evaporation. Water removal can also be done by applying vacuum to the mixture or simply distill the mixture at atmospheric pressure. In principle, phase separation might also be improved by addition of salt or by using specific internals in phase separation devices. Suitable methods are in principle known to the person skilled in the art.

[0081] 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 one aspect of the invention, solids may be removed from the mixture before or after the mixture is allowed to settle, preferably by one or more of the following: filtration, centrifugation, decantation 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.

[0082] 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.

[0083] According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein the process according to step (vii) further comprises step a) and b) a) removal of particulate solids from the reaction mixture (M1); b) separation of the amine component and the polyol components of the reaction mixture (M1).

[0084] In the context of the present invention, the amine component is to be understood as a component obtained in the depolymerization process comprising an isocyanate precursor like an amine, carbamate or urea.

[0085] In work-up by distillation, compounds are separated according to their volatility, with more volatile 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. Generally, the "volatility” of a liquid may be described using its vapor pressure, wherein a high vapor pressure indicates a high volatility, and vice versa.

[0086] 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.

[0087] 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.

[0088] Alternatively, the polyol may be recovered by extraction from the depolymerization mixture using a suitable extractant or a pair of extractants. It is also possible to precipitate the polyamine component in the form of its hydrochloride by adding HCI and extracting the polyol component with a suitable solvent for example as described in DE2854940A1, which is preferably dissolving the polyol component but not the hydrochlorides of the polyamine component. The hydrochloride 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 polyisocyanates for the polyurethane synthesize. In case of MDA*HCI or PMDA*HCI 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 comprise one or more of the following:

[0089] - filtration;

[0090] - centrifugation;

[0091] - partial or full evaporation of the phase in one or more evaporators;

[0092] - contacting the phase with an ion exchange material;

[0093] - contacting the phase with one or more adsorbents.

[0094] After the work-up, the phase, which is polyol substance rich, preferably has 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.

[0095] Preferably, the process further comprises work-up of the mixture by purification of the amine substance, for example including distillation, in order to purify the amine substance.

[0096] It is understood that the separation process described above can be combined with any of the various embodiments of the inventive process described herein.

[0097] With the process of the present invention, about 70% or more, in particular about 80% or more, preferably 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 release is about 90 % or more, preferably of 97 wt.-% or more, in particular of 99 wt.-% or more.

[0098] 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.

[0099] Preferably, the polyol composition for flexible foams comprises or consists of one or more polyols having a molecular weight of about 2500 to about 3700 g / mole, a nominal OH functionality of about 3 and having an OH number of about 45 mg KOH / g to about 56 mg KOH / g.

[0100] 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 section 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.

[0101] For the use of the amine substance in the isocyanate production, the amine substance needs to be essentially free of water, alcohols, polyol substance, residual metals and silicon compounds.

[0102] 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.

[0103] According to a further embodiment, the present invention therefore is also directed to the process as disclosed above, wherein the process further comprises step (viii)

[0104] (viii) conversion of the amine component to obtain an isocyanate composition.

[0105] In the context of the present invention, the term "isocyanate composition” encompasses all isocyanates 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 composition comprises at least one isocyanate.

[0106] The conversion according to step (viii) 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 conversion 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 25 870847 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 example 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 disclosed in WO2018 / 185168 and EP 3 250 622 B1.

[0107] Preferably, the phosgenation comprises admixing a solvent to the amine component and stirring, 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 polyamine 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 preferably in the range of from 110 to 130 °C, obtaining a mixture comprising one or more polyisocyanates.

[0108] According to a further aspect, the present invention is also directed to the use of the polyol composition according to the present invention or a polyol composition obtained or obtainable according to the process of the present invention for the preparation of polyurethanes.

[0109] The present invention further relates to a process for preparing a polyurethane material by reacting 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 present invention.

[0110] The present invention further relates to a process for preparing a polyurethane material by reacting 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 present invention.

[0111] In embodiments, in which the polyol substance obtained by the process according to the present invention is used in a process for preparing a polyurethane material, up to 100 % of virgin polyol can be replaced by the recovered polyol substance without significant drawback in product quality.

[0112] All advantages and / or features described in connection with the process for recovering a polyol substance also apply for the process for preparing a polyurethane material.

[0113] Preferably, the polyurethane material is used in a mattress or a furniture part or a part of a car seat.

[0114] The present invention is also directed to the isocyanate composition obtained or obtainable according 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 composition obtained or obtainable according to the process according to the present invention for the preparation of polyurethanes. For example TDI or MDI produced according 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. It is also possible that the recycled amine substance obtained by the process according to the present invention is phosgenated together with virgin MDA or TDA to achieve isocyanate compositions comprising recycled and virgin Isocyanate molecules which can as well be utilized to produce polyurethane foams.

[0115] The produced polyurethane material can be used 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)

[0116] 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 implicitly even if this combination is not mentioned explicitly.

[0117] 1 . A process for recycling waste polyurethane material at least comprising the steps of

[0118] (i) providing a waste polyurethane material (W);

[0119] (ii) separating of the polyurethane material (PU1) and further components of the waste polyurethane material (W);

[0120] (iii) sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2);

[0121] (iv) subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2);

[0122] (v) sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3);

[0123] (vi) depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M 1 );

[0124] (vii) separation of the components of mixture (M 1 ).

[0125] 2. The process according to embodiment 1, wherein the depolymerization according to step (vi) is carried out by a method selected from hydrolysis, acidolysis, alcoholysis, such as glycolysis, hydroalcoholysis such as hydroglycolysis, hydrogenation, hydroammonolysis, hydroaminolyse or aminolysis. The process according to any one of embodiments 1 or 2, wherein the process according to step (vii) further comprises step a) and b) a) removal of particulate solids from the reaction mixture (M1); b) separation of the amine component and the polyol components of the reaction mixture (M1). The process according to any one of embodiments 1 to 3, wherein the mechanical treatment according to step

[0126] (iv) is selected from the group consisting of milling, beating, shredding, tearing and mixtures of two or more of these treatments. The process according to any one of embodiments 1 to 4, wherein the polyurethane materials are selected from the group consisting of toluene diisocyanate (TDI) derived polyurethane materials and methylenedi(phe- nylisocyanate) (MDI) derived polyurethane materials. Polyol composition obtained or obtainable according to the process of any one of embodiments 1 to 5. Polyol composition obtained or obtainable according to the process for recycling waste polyurethane material at least comprising the steps of

[0127] (I) providing a waste polyurethane material (W);

[0128] (II) separating of the polyurethane material (PU1) and further components of the waste polyurethane material (W);

[0129] (ill) sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2);

[0130] (iv) subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2);

[0131] (v) sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3);

[0132] (vi) depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M1);

[0133] (vii) separation of the components of mixture (M 1 ). Use of the polyol composition according to embodiment 6 or 7 or a polyol composition obtained or obtainable according to the process of any one of embodiments 1 to 5 for the preparation of polyurethanes. The process according to any one of embodiments 1 to 5, wherein the process further comprises step (viii)

[0134] (viii) conversion of the amine component to obtain an isocyanate composition. A process for recycling waste polyurethane material at least comprising the steps of

[0135] (i) providing a waste polyurethane material (W);

[0136] (ii) separating of the polyurethane material (PU1) and further components of the waste polyurethane material (W);

[0137] (iii) sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2);

[0138] (iv) subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2);

[0139] (v) sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3);

[0140] (vi) depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M1 );

[0141] (vii) separation of the components of mixture (M 1 ),

[0142] (viii) conversion of the amine component to obtain an isocyanate composition. Isocyanate composition obtained or obtainable according to the process according to embodiment 9 or 10. Isocyanate composition obtained or obtainable according to the process for recycling waste polyurethane material at least comprising the steps of

[0143] (i) providing a waste polyurethane material (W);

[0144] (ii) separating of the polyurethane material (PU1) and further components of the waste polyurethane material (W); (iii) sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2);

[0145] (iv) subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2);

[0146] (v) sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3);

[0147] (vi) depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M1 );

[0148] (vii) separation of the components of mixture (M 1 ),

[0149] (viii) conversion of the amine component to obtain an isocyanate composition.

[0150] 13. Use of the isocyanate composition according to embodiment 11 or 12 or an isocyanate composition obtained or obtainable according to the process according to embodiment 9 or 10 for the preparation of polyurethanes.

[0151] 14. A process for recycling waste polyurethane foam at least comprising the steps of

[0152] (I) providing a waste polyurethane foam (W);

[0153] (ii) separating of the polyurethane foam (PU1) and further components of the waste polyurethane foam (W);

[0154] (iii) sorting and separating the polyurethane foam based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane foam (PU2);

[0155] (iv) subjecting the purified polyurethane foam (PU2) to a mechanical treatment to give a comminuted polyurethane foam (PU2);

[0156] (v) sorting the comminuted polyurethane foam (PU2) and removing impurities to give a purified comminuted polyurethane foam (PU3);

[0157] (vi) depolymerization of the comminuted polyurethane foam (PU3) to give a reaction mixture (M 1 );

[0158] (vii) separation of the components of mixture (M 1 ). 15. The process according to embodiment 14, wherein the depolymerization according to step (vi) is carried out by a method selected from hydrolysis, acidolysis, alcoholysis, such as glycolysis, hydroalcoholysis such as hydroglycolysis, hydrogenation, hydroammonolysis, hydroaminolyse or aminolysis.

[0159] 16. The process according to any one of embodiments 14 or 15, wherein the process according to step (vii) further comprises step a) and b) a) removal of particulate solids from the reaction mixture (M1); b) separation of the amine component and the polyol components of the reaction mixture (M1).

[0160] 17. The process according to any one of embodiments 14 to 16, wherein the mechanical treatment according to step (iv) is selected from the group consisting of milling, beating, shredding, tearing and mixtures of two or more of these treatments.

[0161] 18. The process according to any one of embodiments 14 to 17, wherein the polyurethane foams are selected from the group consisting of toluene diisocyanate (TDI) derived polyurethane foams and methylenedi (phenyl I- socyanate) (MDI) derived polyurethane foams.

[0162] 19. Polyol composition obtained or obtainable according to the process of any one of embodiments 14 to 18.

[0163] 20. Polyol composition obtained or obtainable according to the process for recycling waste polyurethane foam at least comprising the steps of

[0164] (I) providing a waste polyurethane foam (W);

[0165] (II) separating of the polyurethane foam (PU1) and further components of the waste polyurethane foam (W);

[0166] (ill) sorting and separating the polyurethane foam based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane foam (PU2);

[0167] (iv) subjecting the purified polyurethane foam (PU2) to a mechanical treatment to give a comminuted polyurethane foam (PU2);

[0168] (v) sorting the comminuted polyurethane foam (PU2) and removing impurities to give a purified comminuted polyurethane foam (PU3); (vi) depolymerization of the comminuted polyurethane foam (PU3) to give a reaction mixture (M1);

[0169] (vii) separation of the components of mixture (M 1 ).

[0170] 21. Use of the polyol composition according to embodiment 19 or 20 or a polyol composition obtained or obtainable according to the process of any one of embodiments 14 to 18 for the preparation of polyurethanes.

[0171] 22. The process according to any one of embodiments 14 to 18, wherein the process further comprises step (viii)

[0172] (viii) conversion of the amine component to obtain an isocyanate composition.

[0173] 23. A process for recycling waste polyurethane foam at least comprising the steps of

[0174] (I) providing a waste polyurethane foam (W);

[0175] (ii) separating of the polyurethane foam (PU1) and further components of the waste polyurethane foam (W);

[0176] (ill) sorting and separating the polyurethane foam based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane foam (PU2);

[0177] (iv) subjecting the purified polyurethane foam (PU2) to a mechanical treatment to give a comminuted polyurethane foam (PU2);

[0178] (v) sorting the comminuted polyurethane foam (PU2) and removing impurities to give a purified comminuted polyurethane foam (PU3);

[0179] (vi) depolymerization of the comminuted polyurethane foam (PU3) to give a reaction mixture (M 1 );

[0180] (vii) separation of the components of mixture (M 1 ),

[0181] (viii) conversion of the amine component to obtain an isocyanate composition.

[0182] 24. Isocyanate composition obtained or obtainable according to the process according to embodiment 22 or 23.

[0183] 25. Isocyanate composition obtained or obtainable according to the process for recycling waste polyurethane foam at least comprising the steps of (I) providing a waste polyurethane foam (W);

[0184] (II) separating of the polyurethane foam (PU1) and further components of the waste polyurethane foam (W);

[0185] (ill) sorting and separating the polyurethane foam based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane foam (PU2);

[0186] (iv) subjecting the purified polyurethane foam (PU2) to a mechanical treatment to give a comminuted polyurethane foam (PU2);

[0187] (v) sorting the comminuted polyurethane foam (PU2) and removing impurities to give a purified comminuted polyurethane foam (PU3);

[0188] (vi) depolymerization of the comminuted polyurethane foam (PU3) to give a reaction mixture (M1 );

[0189] (vii) separation of the components of mixture (M 1 ),

[0190] (viii) conversion of the amine component to obtain an isocyanate composition.

[0191] 26. Use of the isocyanate composition according to embodiment 24 or 25 or an isocyanate composition obtained or obtainable according to the process according to embodiment 22 or 23 for the preparation of polyurethanes.

[0192] 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.

[0193] Examples

[0194] Three cases were compared. The differences of the examples are summarized in table 1 . Table 1

[0195] By removing all foreign materials such as textiles, foreign polymers, wood, innersprings (metal) and other polyurethane foam types, significantly less material is transported unnecessarily. Second (overbelt) sorting improves be- cause there is not too much wrong material on the conveyor.

[0196] By "dismantling" or taking apart the mattress (separating the foam from the rest of all materials), approximately 66% of the material stream is separated from the foam value product. (34% of the mass is foam). Approximately 60% of the foam mass is the "conventional" or "standard" foam required for the process. So about 20% of the average total mattress mass is standard foam (desired value product). Pre-screening here, with a statistical false-screening of 10%, can remove much of the unwanted, non-"standard" foam from the stock stream and improve the purity of the stock stream. Overall, without taking into account false-screening and false separation, the "pretreatment" and pre-screening can separate a maximum and ideally about 80% of the stock stream from the value product. The results of the evaluation of quality through post-processing steps are summarized in table 2:

[0197] Table 2

[0198] The quality of the resulting foam was evaluated based on certain foaming properties (Cream Time, Blow Off, Sink back after 10 min, Air Flow). Since these properties depend very much on the ambient conditions, it is customary to carry out a so-called reference test with virgin polyol for each test.

[0199] Table 3 below shows the deviation of the foaming properties of the test with re-polyol compared to the foaming properties of the test with virgin polyol.

[0200] Deviation to reference foaming test

[0201] Quality paramter(Re Polyol) — Quality parameter (virgin polyol) Quality parameter (virgin poyol)

[0202] For example:

[0203] Deviation to reference foaming test for cream time

[0204] Cream time (Re Polyol) — Cream time (virgin Polyol) Cream time (virgin Polyol)

[0205] A lower deviation to the daily reference test is better and produces a foam that has smaller deviations in the quality parameters of the finished foam product. A value of 0% would be the best result for a Re-polyol as it would result in the same value as the virgin polyol that sets the reference to which the Re-polyol is compared. In the following table, the invention shows that it has a smaller deviation to the reference test with virgin polyol in the quality parameters: "cream time”, "blow-off”, "sink back after 10 min” and "air flow”. Table 3

[0206] Literature cited:

[0207] US 9,023,907 B2

[0208] WO 2015 / 121057

[0209] WO 2013 / 13978

[0210] "Kunststoffhandbuch [Plastics handbook], volume 7, Polyurethane [Polyurethanes]", Carl Hanser Verlag, 3rd edition 1993, chapter 3.1, 3.2 and 3.3.2

[0211] WO 2006 / 034800

[0212] EP 0090444

[0213] WO 2005 / 090440

[0214] W02010 / 130652A2

[0215] EP22178796.3

[0216] EP22178797.1.

[0217] DE2854940A1

[0218] Ullmann's Encyclopedia of Industrial Chemistry, 7thed. Vol. 20, 2012, p. 63-82

[0219] WO 99 / 54289 A

[0220] WO 2004 / 056756 A

[0221] Ullmann's Encyclopedia of Industrial Chemistry, 4thed. Vol. 13, 2012, p. 353

[0222] DE 25870847 A

[0223] EP 1532107 A

[0224] EP 0570799 A

[0225] EP 0289840 A

[0226] EP 2044009 A1

[0227] WO 2013 / 060836 A

[0228] WO 2013 / 079517 A

[0229] WO 2022 / 106716

[0230] EP 1761483 B1

[0231] EP 2079684 B1 EP 2188247 B1

[0232] EP 2408738 B1

[0233] EP 2539314 B1

[0234] WO2018 / 185168 EP 3 250 622 B1

Claims

Claims1 . A process for recycling waste polyurethane material at least comprising the steps of(I) providing a waste polyurethane material (W);(II) separating of the polyurethane material (PU1) and further components of the waste polyurethane material (W);(ill) sorting and separating the polyurethane material based on the type of isocyanate used and / or based on the type of polyol used to give a purified polyurethane material (PU2);(iv) subjecting the purified polyurethane material (PU2) to a mechanical treatment to give a comminuted polyurethane material (PU2);(v) sorting the comminuted polyurethane material (PU2) and removing impurities to give a purified comminuted polyurethane material (PU3);(vi) depolymerization of the comminuted polyurethane material (PU3) to give a reaction mixture (M 1 );(vii) separation of the components of mixture (M 1 ).

2. The process according to claim 1, wherein the depolymerization according to step (vi) is carried out by a method selected from hydrolysis, acidolysis, alcoholysis, such as glycolysis, hydroalcoholysis such as hydroglycolysis, hydrogenation, hydroammonolysis, hydroaminolyse or aminolysis.

3. The process according to any one of claims 1 or 2, wherein the process according to step (vii) further comprises step a) and b) a) removal of particulate solids from the reaction mixture (M 1 ); b) separation of the amine component and the polyol components of the reaction mixture (M 1 ).

4. The process according to any one of claims 1 to 3, wherein the mechanical treatment according to step (iv) is selected from the group consisting of milling, beating, shredding, tearing and mixtures of two or more of these treatments.

5. The process according to any one of claims 1 to 4, wherein the polyurethane materials are selected from the group consisting of toluene diisocyanate (TDI) derived polyurethane materials and methylenedi(phenylisocya- nate) (MDI) derived polyurethane materials.

6. Polyol composition obtained or obtainable according to the process of any one of claims 1 to 5.

7. Use of the polyol composition according to claim 6 or a polyol composition obtained or obtainable according to the process of any one of claims 1 to 5 for the preparation of polyurethanes.

8. The process according to any one of claims 1 to 5, wherein the process further comprises step (viii)(viii) conversion of the amine component to obtain an isocyanate composition.

9. Isocyanate composition obtained or obtainable according to the process according to claim 8.

10. Use of the isocyanate composition according to claim 9 or an isocyanate composition obtained or obtainable according to the process according to claim 8 for the preparation of polyurethanes.

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