Improved process for depolymerizing polyurethanes

Abstract

The present invention relates to an improved process for the production of recycled polyols ("PPU") and recycled amines ("APU") from polyurethanes ("PU"), in particular polyurethane waste. The PU is hydrolyzed and a crude product ("RH") is obtained comprising an organic phase ("PO") typically comprising the major parts of the polyol PPU and the amine APU resulting from the hydrolysis of the PU and an aqueous phase ("PW"). At least a portion of the PO ("PO1") is then separated from the RH. The residual water W and the amine APU are separated from the PO1 by distillation to obtain water vapor V and an amine fraction FA. Then, at least a portion of PO3 of the remaining organic phase PO2, typically comprising a major portion of the polyol PPU, is further purified by stripping, where the water vapor V is used as a countercurrent stripping gas. Preferably distilled water from PO1 and the stripping step are carried out in the same column K1.

Description

Technical Field

[0001] This invention relates to polyols ("P") used in the production of recycled polyurethane ("PU"), particularly polyurethane waste. PU ") and recycled amines ("A PU An improved method is proposed. PU is hydrolyzed to obtain a product containing an organic phase ("P"). O ") and aqueous phase ("P W The crude product of "R" H The organic phase typically comprises the polyol P obtained from the hydrolysis of the PU. PU and amine A PU The main part. Then, P O At least a part of ("P") O1 ") From R H Separation from P by distillation. O1 Separate the residual water W and amine A PU To obtain water vapor V and amine fraction F A Then, the remaining organic phase P is stripped. O2 At least a portion of P O3 Further purification revealed that the organic phase typically contained the polyol P. PU The main part, wherein the water vapor V is used as countercurrent stripping gas. Preferably, from P O1 The distilled water and the stripping step are carried out in the same column K1.

[0002] The method according to the invention is highly energy and resource efficient. In particular, it reduces the number of necessary distillation equipment by combining distillation and stripping equipment, thus simplifying the overall equipment cost. Background Technology

[0003] Polyurethane is a highly useful material in the production of rigid and flexible foams, solid and microporous elastomers, sealants, coatings, and adhesives. The versatility, relatively low cost, and excellent performance of polyurethane have led to the rapid growth of the polyurethane industry over the past 50 years. Currently, thousands of tons of polyurethane are produced worldwide each year. Unfortunately, most polyurethanes are thermosetting materials that are cross-linked to varying degrees. Unlike thermoplastics such as polyethylene, polypropylene, and polystyrene, polyurethane waste or waste cannot therefore be easily remelted or reprocessed into usable items. Due to the strong desire, for both economic and environmental reasons, to reuse or recycle the large quantities of polyurethane waste or waste generated annually, rather than incinerating or disposing of it in landfills, considerable effort has been invested in designing methods to recover usable chemical components from polyurethane waste materials.

[0004] WO 2023 / 083968 A1 discloses a method for cleaving PUs with a reagent and water and a catalyst, the reagent comprising a primary or secondary organic amine and / or an amino alcohol. The resulting products can be recovered by distillation and / or stripping.

[0005] WO 2023 / 072985 A1 gives an overview of the most important methods for PU recycling, namely hydrolysis, glycolysis and a mixed form ("hydroglycolysis"). It also emphasizes the challenges of large-scale PU recycling, in particular in terms of resource efficiency and technical requirements for PU recycling plants. In particular, there is a need in the art for a method which allows for an efficient separation, purification and recycling of the typical cleavage products obtained during PU depolymerization, namely amines and polyols as the basic building blocks of any PU polymer.

[0006] The problem underlying the present invention is therefore to provide a method for recycling PUs, i.e. for producing recycled polyols and recycled amines from PUs, which is simple in its procedural sequence, resource-efficient and allows for a simplified installation engineering. SUMMARY

[0007] Surprisingly, it has now been found that a method for producing recycled polyols and recycled amines from PUs solves the above-mentioned problems.

[0008] The method according to the present invention is a method for producing at least one recycled polyol P PU and at least one recycled amine A PU from at least one polyurethane PU, wherein the at least one polyurethane PU is preferably provided as a PU foam, more preferably as a flexible PU foam.

[0009] The method according to the present invention comprises the following steps: a. at least partially hydrolyzing the PU by contacting the PU with water W and at least one base B, to obtain a crude product R H , which crude product R H comprises polyols P PU , amines A PU , water W, at least one base B and optionally solids S, wherein the crude product R H comprises an organic phase P O and an aqueous phase P W , b. separating at least a portion P O of the organic phase P O1 from the crude product R H , wherein P O1 comprises polyols P PU , amines APU , water W, c. separating at least a part of the water W and of the amine A PU from P O1 by distillation, to obtain: - water vapor V, - a fraction F A , the fraction F A comprising amine A PU , - an organic phase P O2 , the organic phase P O2 comprising polyol P PU , optionally amine A PU and optionally water W, d. purifying at least a part P O2 of the organic phase P O3 by stripping, characterized in that, in step d, water vapor V is used as stripping gas in counter-current with respect to P O3 .

[0010] Thus, the process according to the application allows an efficient use of the water vapor obtained during the distillation of the organic phase, thus saving resources and facilitating the overall process. BRIEF DESCRIPTION OF DRAWINGS

[0011] The drawing shows a preferred embodiment of the process according to the application. The organic phase P H <1> of a hydrolyzed crude product R O1 <1> is fed into an evaporator <2> connected to a distillation column K1<4>. The crude product R H is obtained after hydrolysis of a PU using a base B and optionally a quaternary ammonium salt Q as phase transfer catalyst. The organic phase P O1 <1> comprises polyol P PU , amine A PU , residual water W, and at least one of quaternary ammonium salt Q, aminic decomposition products of Q. In the evaporator <2>, water and optionally other components, such as amine A O1 <1>, comprised by P PU <1> are separated from P O1<1> is evaporated. Thus, a stream of water vapor V<3> is obtained and conducted into a column K1<4> to get rid of other impurities dragged along. The residue <5> of this distillation step is then conducted to a further purification step, which is usually carried out in a short path evaporator or thin film evaporator or a further distillation column K2. In this further purification step, the polyol P PU and the amine A PU are further separated from each other, preferably by distillation. The polyol fraction <6> obtained in this further purification is then conducted to column K1<4> and can optionally be heated via heat exchanger <10>.

[0012] Within column K1<4>, water vapor V<3> passes through a packing <41>. Above the packing <41>, column K1<4> can comprise an optional condenser <42> for condensing and removing impurities dragged along by water vapor V<3>, such as amine decomposition products of Q and / or other hydrolysis products such as amine A PU . These compounds are removed as condensate via line <7>. Optionally, in case additional water vapor is needed for stripping the polyol P PU , additional liquid water can be fed to column K1<4> via line <8>. Such additional water can be heated via heat exchanger <9>. Optionally, the condensate removed via line <7> can be partially or completely used as reflux into column K1<4> and in this case can be mixed via line <14> with the additional water fed to column K1<4> via line <8>.

[0013] Water vapor V<3> rises to the upper part of column K1<4> and can additionally be heated by a heat exchanger <43> integrated in column K1<4> or outside column K1<4>. Water vapor V<3> then passes through a second packing <44> from the bottom and is contacted with polyol fraction <6> fed from the top of column K1<4>. By means of this countercurrent way of water vapor V<3> and the polyol fraction <6>, the latter is stripped from impurities and a purified polyol fraction <11> is obtained in a liquid collector <45> where it is withdrawn from column K1<4>. The water vapor obtained after stripping contains amine decomposition products of Q and / or other hydrolysis products such as amine A PU . It is withdrawn from the top of column K1<4> and condensed in a condenser <12>. The resulting condensed stream <13> can then be further treated, for example in a further distillation to recycle water which can then be recycled via line <8> to column K1<4> to be used again for stripping and / or isolating the desired amine APU Alternatively, this water can be recycled to the reaction step to produce more hydrolyzed crude product R H and with this more organic phase P O1 <1>. DETAILED DESCRIPTION

[0014] In the process according to the present application, at least one recycled polyol P PU and at least one recycled amine A PU is obtained in the process according to the present application, i.e. in the process comprising the hydrolysis step of the PU PU and A PU can be reused, e.g. for the synthesis of further PUs, in particular PU foams, preferably soft PU foams.

[0015] The polyols P PU , the amines A PU and the at least one polyurethane PU which can be used in the process according to the present application are further described below.

[0016] 1. Polyol P PU The "polyols P PU " encompass any organic compound having two or more isocyanate-reactive groups, preferably two or more OH groups. Such polyols are for example described in JP H04-136017 A, WO 2022 / 042909 A1, WO 2022 / 042910 A1, WO 2023 / 072985, WO 2023 / 078802 A1.

[0017] The polyols P PU which are recovered in the process of the present application have a structure which is related to the structure of the polyols which are used for the preparation of the polyurethane PU which is processed in the process of the present application.

[0018] Preferably, the at least one polyol P PU is selected from the following: polyether polyols; polyester polyols; hydroxyl group-containing aliphatic polycarbonates, in particular polyether carbonate polyols; natural oil based polyols (NOPs); polymeric polyols (filled polyols); prepolymer polyols; self-catalyzing polyols.

[0019] More preferably, the at least one polyol PPU is selected from the group consisting of polyether polyols, polyester polyols, and even more preferably the at least one polyol P PU is selected from the group consisting of polyether polyols.

[0020] the at least one polyol P PU preferably has an average functionality in the range of 2 to 6, more preferably 2 to 3, most preferably 2.

[0021] "Functionality" means the number of isocyanate-reactive groups, preferably the number of OH groups, per molecule.

[0022] in a mixture M PU of more than one polyol P P "Average functionality" means the number of all isocyanate-reactive groups, preferably all OH groups, in the mixture M P divided by the amount of substance (mol) of all polyols P P in the mixture M PU .

[0023] the at least one polyol P PU preferably has a number average molecular weight in the range of 500 to 15000 g / mol. The number average molecular weight is typically determined by gel permeation chromatography ("GPC"), in particular using polypropylene glycol as a reference and tetrahydrofuran ("THF") as eluent.

[0024] the at least one polyol P PU preferably has an OH number in the range of 10 to 1200 mg KOH / g. The OH number is determined in particular according to DIN standard DIN 53240:1971-12.

[0025] 1.1 Polyether polyols the at least one polyol P PU is preferably selected from the group consisting of polyether polyols, which are known to the person skilled in the art and which are preferably polyethers having primary and / or secondary end groups, preferably hydroxyl groups. Amine-functionalized polyethers (for example "Jeffamine" polyoxypropylamines sold by Texaco Chemical Co.) can also be used. It is preferred to use polyether polyols having hydroxyl end groups.

[0026] the at least one polyol P PUPreferably selected from polyether polyols, which are obtainable by known methods. Such materials are typically prepared by catalytic ring-opening polymerization of one or more cyclic ethers, such as epoxides, oxetanes or oxolanes. Initiators with two or more active hydrogens, such as polyols, amines or acids, can be used to vary the functionality (number of active hydrogens) of the polyether. If more than one type of cyclic ether is used, they can be reacted simultaneously (to give random copolymers) or sequentially (to give block copolymers). Exemplary cyclic ethers include propylene oxide, ethylene oxide, butylene oxide, tetrahydrofuran and oxetane. Examples of polyether polyols include polypropylene glycol, polyethylene glycol, polytetramethylene glycol, polytrimethylene glycol, ethylene oxide-capped polypropylene glycol, random copolymers of ethylene oxide and propylene oxide.

[0027] said at least one polyol P PU Preferably selected from polyether polyols, which are also obtainable by anionic polymerization of alkylene oxides ("AO") in the presence of an alkali metal hydroxide, alkali metal alcoholate or amine as catalyst and by addition of at least one starter molecule ("SM"), which preferably contains two or three reactive hydrogen atoms in bonding form, or cationic polymerization of AO in the presence of a Lewis acid, such as antimony pentachloride or boron trifluoride etherate, or by double metal cyanide catalysis.

[0028] Suitable AO contain two to four carbon atoms. Examples are tetrahydrofuran, 1,3- propylene oxide, 1,2-propylene oxide, 1,2-butylene oxide and 2,3-butylene oxide. Preferably ethylene oxide and 1,2-propylene oxide are used. The alkylene oxides can be used individually, cumulatively, blockwise, alternately or as a mixture.

[0029] The starter molecules SM used can in particular be compounds having at least two, preferably two to eight, hydroxyl groups in their molecule, or compounds having at least two primary amino groups.

[0030] Preferred starter molecules SM are selected from the following: - water; - di-, tri- or tetraols, in particular selected from ethylene glycol, propane-1,2-diol, propane-1,3-diol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol; - fatty acid triglycerides, wherein at least two of the fatty acids carry at least one -OH group, preferably castor oil, which is a triglyceride wherein at least two, preferably each of the three fatty acid residues is 12-hydroxy-9-octadecenoic acid (known as "ricinoleic acid"); - higher polyfunctional polyols, in particular sugar compounds, such as glucose, sorbitol, mannitol and sucrose; - polyphenols, resols, such as oligomeric condensation products of phenol and formaldehyde, and Mannich condensates of phenols, formaldehyde and dialkanolamines, and melamine, or amines such as aniline, ethylenediamine ("EDA"), toluenediamine ("TDA"), diphenylmethane diamine ("MDA", which is preferably diphenylmethane 2,4'-diamine or diphenylmethane 2,2'-diamine), 1,5-pentanediamine ("PMDA").

[0031] The choice of suitable starter molecules SM depends on the particular field of use of the resulting polyether polyol in the production of polyurethanes (e.g. polyols for the production of soft PU foams differ from those for the production of hard PU foams).

[0032] Polyol P PU is preferably selected from polyether polyols, which can also be obtained from natural sources. Such polyether polyols and their preparation from biological sources are described by H. Sardon, D. Mecerreyes, A. Basterretxea, L. Avérous, C. Jehanno, ACS Sustainable Chem. Eng. 2021, 9 , 10664-10677 (hereinafter "Sardon et al.").

[0033] 1.2 Polyester polyols Polyester polyols are polyols P PU is preferably selected from polyesters, which are esters based on polybasic aliphatic or aromatic carboxylic acids, preferably having two to twelve carbon atoms.

[0034] Examples of aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid, fumaric acid. Examples of aromatic carboxylic acids are phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalene dicarboxylic acids. The polyester polyols are obtained by condensing these polybasic carboxylic acids with polyols, which are preferably diols or triols having two to twelve, more preferably two to six carbon atoms, preferably trimethylolpropane and glycerol.

[0035] Polyol P PU is preferably selected from polyester polyols, which can also be obtained from natural sources. Such polyester polyols and their preparation from biological sources are described by Sardon et al.

[0036] 1.3 Hydroxyl-containing aliphatic polycarbonates Hydroxyl-containing aliphatic polycarbonates are polyols P PU Preferably selected from another group of polyols, the hydroxyl-containing aliphatic polycarbonate is a polyol containing carbon dioxide bonded in the form of carbonate [-OC(=O)-O]. Since carbon dioxide is formed in large quantities as a byproduct in many processes of the chemical industry, from a commercial perspective, the use of carbon dioxide as a comonomer in olefinic polymerization is of particular interest. Partially replacing the olefinic oxygen in polyols with carbon dioxide has the potential to significantly reduce the production cost of polyols. Furthermore, the use of CO2 as a comonomer is very environmentally advantageous because the reaction constitutes a conversion of greenhouse gases into polymers. Such polyols are, for example, produced by J. Xu, E. Feng, J. Song, J Appl Polym Sci. 2014, 131 Description: 10.1002 / app.39822. The preparation of these polyols by adding olefinic oxygen and carbon dioxide to H-functional initiator substances using a catalyst is well known. Various catalyst systems can be used here: the first generation are those with heterogeneous zinc or aluminum salts, such as those described, for example, in US 3,900,424 A or US 3,953,383 A. Furthermore, mononuclear and binuclear metal complexes have been successfully used for the copolymerization of CO2 and olefinic oxygen (WO 2010 / 028362 A1, WO 2009 / 130470 A1, WO 2013 / 022932 A1 or WO 2011 / 163133 A1). The most important class of catalyst systems used for the copolymerization of carbon dioxide and olefinic oxygen are those of bimetallic cyanide catalysts, also known as "DMC catalysts" (US 4,500,704 A, WO 2008 / 058913 A1). Suitable olefinic oxygen and H-functional initiators are those also used to prepare carbonate-free polyether polyols, as described above.

[0037] 1.4 Natural oil-based polyols (NOPs) Polyol P PUPreferred polyols are those based on renewable raw materials, specifically natural oil-based polyols (NOP). Given the long-term limitations of fossil resources (i.e., oil, coal, and natural gas) availability and the backdrop of rising crude oil prices, the use of NOP in the production of PU foam is gaining increasing attention. NOP has been described multiple times in such applications (WO 2005 / 033167 A2, US 2006 / 0293400 A1, WO 2006 / 094227 A2, WO 2004 / 096882 A1, US 2002 / 0103091 A1, WO 2006 / 116456 A1, and WO 2005 / 033167 A2). NOP is now commercially available from various manufacturers (US 2006 / 0167125 A1, US 2006 / 0229375 A1, WO 2009 / 058367 A1). Depending on the base feedstock, such as soybean oil, palm oil, or castor oil (described in Figure 2B of Sardon et al.), and subsequent processing, polyols with different properties are obtained. Essentially, two groups can be distinguished here: a) polyols based on renewable feedstocks, which are modified so that they can be used to produce polyurethanes to a 100% extent (US 2006 / 0167125 A1, US 2006 / 0229375A1); b) polyols based on renewable feedstocks, which, due to their processing and properties, can only replace petrochemical-based polyols in a specific proportion (WO 2009 / 058367 A1). As mentioned above, polyol P... PU The polyether polyols, polyester polyols and other polyols that can be selected can also be obtained from natural sources (see Sardon et al.).

[0038] 1.5 Polymer polyols (filled polyols) Polyol P PU Another preferred class of polyols is the so-called polymeric polyol (filled polyol). A key characteristic of these polyols is that they contain dispersed solid organic fillers, with a solid content of up to 40% or higher. Different types of polymeric polyols are available: SAN, PUD, and PIPA polyols. SAN polyols contain styrene-acrylonitrile-based fillers (…). s tyrene- a crylo n Highly reactive polyols of the dispersion copolymer of itrile ("SAN") and PUD ("poly-urea-dispersion") p oly- u rea- d Polyisocyanate polyols (PIPA) are also highly reactive polyols containing polyurea, existing in dispersed form. poly i socyanate p oly a ddition")) polyols are high-reactivity polyols containing dispersed polyurethane (e.g. formed by in-situ reaction of isocyanate with alkanolamine in a conventional polyol).

[0039] Depending on the application, the preferred solids content is typically between 5 wt% ("wt%" = "wt%") and 40 wt% based on the polyol. The solids content of the polymeric polyol helps to improve the open cell nature, which leads to a more controllable foaming process, especially when TDI ("toluene diisocyanate") is used, so that no foam shrinkage occurs. Thus, the solids content acts as an essential processing aid. An additional function is to control the foam hardness by the solids content in the foam formulation, as a higher solids content leads to a higher foam hardness. Formulations with polymeric polyols have significantly less self-stability, so additional physical stabilization is needed in addition to the chemical stabilization from the crosslinking reaction. Depending on the solids content of the polyol, they can be used alone or in a blend with the above-mentioned unfilled polyols.

[0040] 1.6 Prepolymer polyols Polyol P PU Another class of polyols, preferably selected from, is obtained as a prepolymer reacted via a polyol with isocyanate in a molar ratio of 100:1 to 5:1, preferably 50:1 to 10:1. Such prepolymers are preferably constituted in the form of a solution in a polymer, and the polyol preferably corresponds to the polyol used to make the prepolymer.

[0041] 1.7 Self-catalyzing polyols Polyol P PUAnother class of polyols, preferably selected from, are so-called autocatalytic polyols, in particular autocatalytic polyether polyols. Such polyols are based on, for example, polyether blocks, preferably on ethylene oxide blocks and / or propylene oxide blocks, and additionally comprise catalytically active functional groups, such as nitrogen-containing functional groups, in particular amino groups, preferably tertiary amine functional groups, urea groups and / or nitrogen atom-containing heterocycles. By using such autocatalytic polyols in the production of PU foams, preferably flexible PU foams, the amount of additional catalysts required depending on the application can be reduced, and / or it can be adapted to specific desired foam properties. Suitable polyols are described, for example, in WO 0158976 A1, WO 2005 / 063841 A1, WO 02 / 22702 A1, WO 2006 / 055396 A1, WO 03 / 029320 A1, WO 01 / 58976 A1, US 6,924,321 B2, US 6,762,274 B2, WO 2008 / 079614 A1, WO 2004 / 060956 A1 or WO 2013 / 102053 A1, and can be purchased, for example, under the trade names Voractiv™ and / or SpecFlex™ Activ from Dow.

[0042] Depending on the desired properties of the resulting foam, suitable polyols can advantageously be used, as described, for example, in US 2007 / 0072951 A1, WO 2007 / 111828 A2, US 2007 / 0238800 A1, US 6,359,022 B2 or WO 96 / 12759 A2. Further polyols are known to the person skilled in the art and can be found, for example, in EP 0 380 993 A2 or US 3,346,557 A1, which are hereby incorporated by reference in their entirety.

[0043] 1.8 Preferred polyols 1.8.1) More preferably, the at least one polyol P PU has the general structure according to formula (I): HX 2 -V 1 -X 1 H, wherein the residue V 1 is a divalent hydrocarbon residue, which optionally contains at least one group selected from the group consisting of ester groups, ether groups, thioether groups, amine groups, cyano groups, hydroxyl groups.

[0044] V 1 is preferably selected from the group consisting of alkylene groups, alkenylene groups, alkynylene groups, aromatic hydrocarbon residues, wherein optionally the alkylene groups, alkenylene groups, alkynylene groups and / or aromatic hydrocarbon residues comprise at least one group selected from the group consisting of ester groups, ether groups, thioether groups, amine groups, cyano groups, hydroxyl groups.

[0045] X 1 , X 2 each independently is selected from -0-, -NH-, -N(R')-, -S-, wherein R' is an alkyl group, preferably an alkyl group having 1 to 6 carbon atoms.

[0046] Preferably, X 1 = -0- and X 2 = -0-.

[0047] 1.8.2) the polyol P of formula (I) PU preferably having a general structure selected from formula (I-A), formula (I-B), formula (I-C), even more preferably formula (I-A): wherein q2, q3, q4, q5, q6, q7, q8 are each independently an integer > 2, preferably in the range of 2 to 1000, more preferably in the range of 5 to 500, even more preferably in the range of 10 to 200, wherein V 2 , V 3 , V 4 , V 5 , V 6 , V 7 , V 8 each independently is a group having the formula -C n H 2n -, wherein n is an integer and n = 1 to 100, preferably n = 2 to 50, more preferably n = 2 to 10, even more preferably n = 2 to 6, even more preferably n = 2 to 4, even more preferably n = 2 to 3, Preferably, V 2 , V 3 , V 4 , V 5 , V 6 , V 7 , V 8 each independently is selected from -CH2CH2-, -CH2-CH(CH3)-, -CH(CH3)-CH2-, -CH2CH2CH2-, and wherein the residues V PU in the polyol P according to general structure (I-A) 2 are identical or different, and wherein the residues V PU in the polyol P according to general structure (I-B) 3 are identical or different, and wherein the residues V in the polyol P according to general structure (I-B) PU are identical or different, 4 and wherein the residues V in the polyol P according to general structure (I-B) PU are identical or different, 5 and wherein the residues V in the polyol P according to general structure (I-C) PU are identical or different, 6 and wherein the residues V in the polyol P according to general structure (I-C) PU are identical or different, 7 and wherein the residues V in the polyol P according to general structure (I-C) PU are identical or different. 8

[0048] According to the present application, "-C n H 2n " comprises linear and branched alkylene residues, preferably selected from the group consisting of methylene, ethylene, n-propylene, iso-propylene, more preferably selected from the group consisting of ethylene, n-propylene, iso-propylene.

[0049] The polyol P of formula (I-A), formula (I-B), formula (I-C) PU is a polyether polyol.

[0050] 2. amine A PU The structure of the amine A PU is related to the structure of the polyisocyanate comprised by the polyurethane PU subjected to the process of the present application. As used in the present application, "amine A PU " comprises an amine having two or more amine groups, preferably an amine having two or more primary amine groups in its molecule.

[0051] In a preferred embodiment, the at least one amine A PU has a general structure according to formula (II): H2N-W 1 -NH2, wherein the residue W 1 is a divalent hydrocarbon residue, which optionally contains at least one group selected from the group consisting of ester groups, ether groups, thioether groups, amine groups, cyano groups, hydroxyl groups, amino groups.

[0052] W 1 is preferably selected from the group consisting of alkylene groups, alkenylene groups, alkynylene groups, aromatic hydrocarbon residues, wherein optionally the alkylene groups, alkenylene groups, alkynylene groups and / or aromatic hydrocarbon residues comprise at least one group selected from the group consisting of ester groups, ether groups, amine groups, thioether groups, hydroxyl groups, cyano groups, amino groups.​​​​​

[0053] W 1 More preferably, the residues are selected from alkylene or aromatic hydrocarbon residues, wherein optionally the alkylene and / or aromatic hydrocarbon residues contain at least one group selected from hydroxyl or amino groups.

[0054] 2.1) Even more preferably, W in equation (II) 1 Selected from C1-C6 alkylene compounds and formulas (II-A), (II-B), (II-C), (II-D), and (II-E), and even more preferably selected from C5-alkylene compounds, C6-alkylene compounds, formulas (II-A), (II-B), (II-C), (II-D), and (II-E), wherein In equations (II-A), (II-B), (II-C), (II-D), and (II-E), the use of "( The "" symbol indicates a bond attached to an amino group in formula (II), and the "" symbols in formulas (II-A), (II-B), (II-C), (II-D), and (II-E) represent bonds bonded to an amino group. The ")" symbol indicates a bond that is linked to other amino groups in formula (II).

[0055] In formula (II-A), preferably, "( )"and"( The two bonds marked with ")" are aligned with each other at the aromatic ring.

[0056] In formula (II-B), preferably, "( )"and"( The two bonds marked by ")" are located at the 2,4- or 2,6-position relative to the methyl group on the aromatic ring.

[0057] In equation (II-C), it is not used with "( )"or"( One of the linked aromatic carbon atoms in the bond marked with ")", i.e., the aromatic carbon atom with hydrogen in formula (II-C), can be replaced by a group selected from amino, alkyl (wherein the alkyl is preferably methyl). More preferably, all groups in formula (II-C) not linked with ") )"or"( Each of the linked aromatic carbon atoms in the ")" sign is equipped with hydrogen.

[0058] In formula (II-D), preferably, the two residues bearing the bonds identified with "( " and "( " are in para position with respect to each other at the aromatic ring.

[0059] 2.2) In an even more preferred embodiment, the at least one amine A PU is selected from the group consisting of phenylenediamine, toluenediamine ("TDA"), diamines and polyamines of diphenylmethane ("MDA"), 1,5-pentanediamine ("PDA"), 1,6-hexamethylenediamine ("HDA"), isophorone diamine ("IPDA"), xylylenediamine ("XDA"). Most preferably, the at least one amine A PU is TDA.

[0060] In TDA, the two amino groups are preferably in 2,4-position or 2,6-position with respect to the methyl group at the aromatic ring.

[0061] 3. Polyurethanes PU In step a of the process according to the application, a polyurethane (PU) is used. This PU is then subjected to partial or complete hydrolysis according to step a.

[0062] One of the advantages of the process according to the application is that it is suitable for a wide range of PUs. Thus, the PU to be subjected to step a of the process of the application is not particularly limited, and any known polyurethane PU can be used in the process of the application. Preferably, the polyurethane PU subjected to step a is a polyurethane waste.

[0063] The PU subjected to step a of the application is preferably provided as a PU foam, more preferably as a flexible PU foam.

[0064] In particular, the polyurethane PUs which can be subjected to the process of the application are those prepared from active hydrogen-containing polyols, preferably polyethers, and polyisocyanates. Polyurethanes of this type are well known and described, for example, in US 5,208,379 A, Ulrich, "Urethane Polymers", in Encyclopedia of Chemical Technology, Vol. 23, pp. 576-608 (1983) and Backus et al. , "Polyurethanes", in Encyclopedia of Polymer Science and Technology, Vol. 13, pp. 243-303 (1988).

[0065] Typically, the polyurethane subjected to step a of the process of the present application is a polymer, wherein at least two OH groups of the polyol P PU are each linked via a urethane function to an NH group of the amine A PU and at least two NH groups of the amine A PU are each linked via a urethane function to an OH group of the polyol P PU .

[0066] The PU used in the process of the present application can be derived from any polyisocyanate reactant (i.e., an organic compound containing two or more isocyanate groups). Suitable polyisocyanates include, but are not limited to, aliphatic diisocyanates, cycloaliphatic diisocyanates, arylalkyl diisocyanates, aromatic diisocyanates (e.g., toluene diisocyanates and diisocyanatodiphenyl methanes), aromatic triisocyanates, and isocyanate mixtures, such as the isocyanate commonly referred to as polymeric diphenylmethane diisocyanate ("PMDI"). Of course, modified, masked or blocked polyisocyanates can also be used. The PU subjected to the process according to the present application can also comprise groups selected from the group consisting of allophanate groups, isocyanurate groups, urea groups. If one or more of these groups are present, at least a portion of these groups can be cleaved during step a. The PU subjected to the process of the present application can also include any conventional added reactants or additives known in the art, such as chain extenders or curatives (relatively low molecular weight active hydrogen containing compounds such as glycols and diamines or polyamines), physical or chemical blowing agents, flame retardants, surfactants, fillers, stabilizers, antioxidants, colorants, polymers other than PU polymers (e.g., styrene-acrylonitrile copolymers, as found in polymer polyols), catalysts, such as catalysts that promote the gelation reaction (isocyanate-polyol), the blowing reaction (isocyanate-water), and / or the dimerization or trimerization of isocyanates. The polyurethane can be in solid, microcellular or foam form, and can range from rubbery, elastomeric, soft materials to hard, rigid substances.

[0067] In particular, the at least one PU subjected to step a of the present application comprises at least one polymer strand PU S wherein PU S has m repeating units of the chemical structure (III) linked to each other, which has wherein m is an integer > 4, preferably 4 to 10 6 , even more preferably 10 to 105 even more preferably 100 to 10 4 an integer, wherein PU S the repeating units of chemical structure (III) within PU wherein PU S the repeating units of chemical structure (III) within PU are connected to each other in such a way that the bond identified with "( ) " in a particular repeating unit is connected to the bond identified with "( ) " in the adjacent repeating unit, wherein R 1 is a divalent hydrocarbon residue, which optionally contains at least one group selected from ester groups, ether groups, hydroxyl groups, cyano groups, amine groups, sulfide groups, wherein R 2 is a divalent hydrocarbon residue, preferably comprising aromatic carbon atoms, wherein in those cases where PU comprises more than one (polymeric chain PU S , the one or more residues R S of the first polymeric chain PU 1 may be covalently bound to one or more other residues R S of the same or a second polymeric chain PU 1 .

[0068] In particular, the PU subjected to step a of the process of the present application comprises a polyol P PU and an amine A PU , formally speaking, said polyol P PU and said amine A PU are interconnected to each other via a urethane bond connecting a hydroxyl group of said P PU with an amino group of said A PU . Upon hydrolysis of the PU in step a, the urethane group is cleaved, thus liberating said P PU and A PU .

[0069] In line with this, in a preferred embodiment of the present application (hereinafter abbreviated as "preferred embodiment Θ"), said polyol P PU has a general structure selected from formula (I-A), formula (I-B), formula (I-C) as defined in point 1.8.2), even more preferably formula (I-A) as defined in point 1.8.2), and said at least one amine A PU has a general structure according to formula (II): H2N-W 1 -NH2, wherein residue W 1 ​As defined in point 2.1), or even more preferably, at least one amine A. PU As defined in point 2.2), Furthermore, the at least one PU subjected to step a of the present invention comprises at least one polymer chain PU. S PU S A repeating unit with m interconnected chemical structures (III) has , Where m is an integer ≥ 4, preferably 4 to 10. 6 Even more preferably 10 to 10 5 Even more preferably 100 to 10 4 integers, Among them PU S The repeating units of chemical structure (III) within the cell are identical or at least partially different from each other. Among them PU S The repeating units of the chemical structure (III) within are connected to each other in such a way that the specific repeating unit contains "( The key marked with ") is used in the adjacent repeating unit with "( The key is linked by the identifier ")". Where R 1 Selected from one of the divalent residues according to formula (III-A), formula (III-B1), formula (III-B2), formula (III-C1), and formula (III-C2). Where V 2 V 3 V 4 V 5 V 6 V 7 V 8 As defined in point 1.8.2 for equations (IA), (IB), and (IC), Where q2 in equation (III-A) Through the following relationship q2 = 1 + q2 It depends on q2 as defined by equation (IA); In equations (III-B1) and (III-B2), q3 The following relationship is used: q3 = 1 + q3 It depends on q3 as defined by equation (IB); Where q4 in equation (III-B1) The following relationship is used: q4 = 1 + q4 depending on q4 as defined for formula (I-B); wherein q5 in formula (III-B1) is as defined for formula (I-B); wherein q4 in formula (III-B2) is as defined for formula (I-B); wherein q5 in formula (III-B2) is as defined for formula (I-B); by the following relationship q5 = 1 + q5 depending on q5 as defined for formula (I-B); wherein q6 in formula (III-C1) and (III-C2) by the following relationship q6 = 1 + q6 depending on q6 as defined for formula (I-C); wherein q7 in formula (III-C1) by the following relationship q7 = 1 + q7 depending on q7 as defined for formula (I-C); wherein q8 in formula (III-C1) is as defined for formula (I-C); wherein q7 in formula (III-C2) is as defined for formula (I-C); wherein q8 in formula (III-C2) by the following relationship q8 = 1 + q8 depending on q8 as defined for formula (I-C); wherein the bond marked with "(#)" in formula (III-A), formula (III-B1), formula (III-B2), formula (III-C1), formula (III-C2) corresponds to the bond marked with "( )" in formula (III), and wherein the bond marked with "(##)" in formula (III-A), formula (III-B1), formula (III-B2), formula (III-C1), formula (III-C2) corresponds to the bond from R 1 to an oxygen atom in formula (III), i.e. this bond from R 1 is different from the bond marked with "( )" in formula (III), and wherein R 2Selected from C1-C6 alkylene and formulas (II-A), (II-B), (II-C), (II-D), and (II-E), and even more preferably selected from C5-alkylene, C6-alkylene, and formulas (II-A), (II-B), (II-C), (II-D), and (II-E) as defined in paragraph 2.1 above, wherein in the context of formula (III), the use of "( The "" symbol indicates a bond bonded to the nitrogen atom of a carbamate functional group in formula (III), and the "" symbols in formulas (II-A), (II-B), (II-C), (II-D), and (II-E) represent bonds bonded to the nitrogen atom of a carbamate functional group. The ")" symbol indicates a bond that is connected to the nitrogen of other urethane functional groups in formula (III).

[0070] The PU subjected to step a of the method of the present invention, particularly the polymer chain PU in embodiment Θ. S It may contain additional residues R as defined above. 1 and residue R 2 Different repeating units. For example, it can contain additional repeating units derived from at least one unit selected from: - Polyether polyols, especially those as defined in point 1.1 above; - Polyester polyols, especially those specified in point 1.2 above; - Hydroxyl-containing aliphatic polycarbonates, especially polyether carbonate polyols, particularly as defined in point 1.3 above; -Natural oil-based polyols (NOPs), particularly as defined in point 1.4 above; - Polymer polyols (filled polyols), especially as defined in point 1.5 above; - Prepolymer polyols, especially those as defined in point 1.6 above; - Self-catalytic polyols, especially those defined in point 1.7 above.

[0071] 4. Step a In step a of the method according to the invention, the PU is at least partially hydrolyzed by contacting the PU with water and at least one base B.

[0072] Hydrolysis reactions of this type of PU are known to those skilled in the art and are described, for example, in WO 2023 / 083968A1 and WO 2023 / 072985 A1. These documents compare hydrolysis with other reactions used to cleave PU, such as glycolysis.

[0073] US 5,208,379 A also discloses typical hydrolysis conditions.

[0074] "Hydrolysis" in the context of the present application means the cleavage of at least a portion of the urethane groups in the PU with water molecules (as nucleophiles) to yield the corresponding amines and polyols.

[0075] 4.1 Base B The at least one base B used in step a can be chosen by the person skilled in the art from his knowledge.

[0076] Preferably, the at least one base B is selected from the group consisting of alkali metal phosphates, alkaline earth metal phosphates, alkali metal hydrogen phosphates, alkaline earth metal hydrogen phosphates, alkali metal carbonates, alkaline earth metal carbonates, alkali metal silicates, alkaline earth metal silicates, alkali metal bicarbonates, alkaline earth metal bicarbonates, alkali metal carboxylates, in particular alkali metal acetates, alkaline earth metal carboxylates, in particular alkaline earth metal acetates, alkali metal sulfites, alkaline earth metal sulfites, ammonium hydroxide, alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides.

[0077] More preferably, the at least one base B is selected from the group consisting of alkali metal phosphates, alkali metal hydrogen phosphates, alkali metal carbonates, alkali metal silicates, alkali metal bicarbonates, alkali metal carboxylates, wherein the carboxylates are in particular acetates, alkali metal sulfites, ammonium hydroxide, alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides.

[0078] The alkali metal comprised by base B is preferably selected from the group consisting of potassium, sodium, lithium, more preferably from the group consisting of potassium, sodium.

[0079] The alkaline earth metal comprised by base B is preferably selected from the group consisting of beryllium, magnesium, calcium, strontium, barium, more preferably from the group consisting of magnesium, calcium.

[0080] Even more preferably, the at least one base B is selected from the group consisting of potassium carbonate, sodium carbonate.

[0081] In a preferred embodiment, the ratio of the total weight of all bases B used in step a relative to the total weight of all PUs subjected to step a is in the range of 50:1 to 1 :1, preferably 10:1 to 2:1, most preferably 4:1.

[0082] 4.2 Phase transfer catalyst In another preferred embodiment, the hydrolysis in step a is catalyzed with at least one phase transfer catalyst selected from the group consisting of quaternary ammonium salts Q, organic sulfonates, preferably at least one phase transfer catalyst selected from the group consisting of quaternary ammonium salts Q.

[0083] The quaternary ammonium salt Q preferably has the general structure R 1 R 2 R 3 R 4 NX, wherein R 1 , R 2 , R 3 and R 4 are identical or different and each is a hydrocarbon radical selected from alkyl, aryl, arylalkyl, and X is selected from hydroxide, carbonate, bicarbonate, hydrogen sulfate, carboxylate (wherein the carboxylate is preferably acetate), halide (wherein the halide is preferably selected from chloride and bromide), alkyl sulfate (wherein the alkyl sulfate is preferably selected from methyl sulfate, ethyl sulfate). Preferably, X = hydroxide, hydrogen sulfate. Most preferably, X = hydroxide.

[0084] The quaternary ammonium salt Q preferably comprises an ammonium cation having 6 to 30 carbon atoms.

[0085] The organic sulfonate preferably comprises at least 7 carbon atoms.

[0086] In a preferred embodiment, the hydrolysis in step a is catalyzed with at least one quaternary ammonium salt Q, even more preferably the at least one quaternary ammonium salt Q comprises a cation selected from tetrabutylammonium cation, benzyltrimethylammonium cation. Even more preferably, the at least one quaternary ammonium salt Q is selected from tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, tetrabutylammonium hydrogen sulfate.

[0087] In those cases where at least one quaternary ammonium salt Q is used in step a, it is further preferred that the weight of all quaternary ammonium salts Q used in step a is at least 0.5 weight percent (= "wt%"), more preferably in the range of 0.5 to 15 wt%, even more preferably in the range of 0.75 to 10 wt%, particularly preferably in the range of 0.90 to 8 wt%, particularly preferably in the range of 1.0 to 7 wt%, based on the total weight of the PU subjected to step a.

[0088] In an alternative embodiment of the process of the present application, the at least partial hydrolysis according to step a is carried out without the addition of a phase transfer catalyst.

[0089] 4.3 Base-catalyst combination In a preferred embodiment of the process of the present application, the at least one base B is used in step a in the form of a "base-catalyst-combination" with at least one quaternary ammonium salt Q or organic sulfonate. Even more preferably, the at least one base B is used in step a in the form of a "base-catalyst-combination" with at least one quaternary ammonium salt Q.

[0090] Even more preferably, the base-catalyst combination is selected from BCC1, BCC2, BCC3, in particular from BCC1, BCC2.

[0091] BCC1 comprises a base B1 and a quaternary ammonium ion Q1, or a base B1 and an organic sulfonate S1, preferably BCC1 comprises a base B1 and a quaternary ammonium ion Q1, wherein B1 comprises an alkali metal cation and / or an ammonium cation and has a pK value of 1 to 10 at 25 °C b and wherein Q1 comprises an ammonium cation comprising 6 to 30 carbon atoms and wherein S1 comprises at least 7 carbon atoms.

[0092] More preferably, Q1 has the general structure R 1 R 2 R 3 R 4 NX, wherein - R 1 and R 2 are identical or different and are an alkyl group having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, particularly preferably 1 to 5, most preferably 1 to 4 carbon atoms, wherein the alkyl group can be linear, branched, cyclic, saturated or unsaturated, most preferably linear, saturated, - R 3 is selected from an alkyl group having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, particularly preferably 1 to 5, most preferably 1 to 4 carbon atoms, an aryl group having 6 to 14, preferably 6 to 12, most preferably 6 to 10 carbon atoms, and an aralkyl group having 7 to 14, preferably 7 to 12, most preferably 7 to 10 carbon atoms, wherein the alkyl group can be linear, branched, cyclic, saturated or unsaturated, most preferably linear, saturated, and - R 4 is selected from an alkyl group having 3 to 12, preferably 3 to 10, more preferably 3 to 7, most preferably 4 to 6 carbon atoms, an aryl group having 6 to 14, preferably 6 to 12, most preferably 6 to 10 carbon atoms, and an aralkyl group having 7 to 14, preferably 7 to 12, most preferably 7 to 10 carbon atoms, wherein the alkyl group can be linear, branched, cyclic, saturated or unsaturated, most preferably linear, saturated, and - X is selected from the group consisting of carbonate, bicarbonate, acetate, hydroxide, halide (wherein the halide is preferably selected from the group consisting of chloride and bromide), hydrogen sulfate, alkyl sulfate (wherein the alkyl sulfate is preferably selected from the group consisting of methyl sulfate and ethyl sulfate).

[0093] Even more preferably, Q1 has a general formula structure R 1 R 2 R 3 R 4 NX, where, Select R 1 To R 4 This results in the total number of carbon atoms in the quaternary ammonium cation being 6 to 14, preferably 7 to 14, and more preferably 8 to 13. or, Select R 1 To R 4 The total number of carbon atoms in the quaternary ammonium cation is 15 to 30, preferably 15 to 28, more preferably 15 to 24, even more preferably 16 to 22, and most preferably 16 to 20.

[0094] BCC2 contains the base B2 and the quaternary ammonium ion Q2, wherein B2 has a pK value of <1 at 25°C. b The value, wherein Q2 comprises an ammonium cation containing 6 to 14 carbon atoms, preferably 7 to 12 carbon atoms if the ammonium cation contains a benzyl residue.

[0095] More preferably, Q2 has a general formula R 1 R 2 R 3 R 4 NX, where, - R 1 To R 3 The alkyl group may be the same or different, and may have 1 to 6, preferably 1 to 5, more preferably 1 to 4, even more preferably 1 to 3, particularly preferably 1 or 2, and most preferably 1 carbon atom, wherein the alkyl group may be linear, branched, cyclic, saturated or unsaturated, and most preferably linear or saturated. - R 4 The alkyl group is selected from alkyl groups having 3 to 11, preferably 3 to 10, more preferably 3 to 8, and most preferably 4 to 6 carbon atoms; aryl groups having 6 to 11, preferably 6 to 10, and most preferably 6 to 8 carbon atoms; and aralkyl groups having 7 to 11, preferably 7 to 10, and most preferably 7 to 9 carbon atoms, wherein the alkyl group can be linear, branched, cyclic, saturated, or unsaturated, and most preferably linear or saturated alkyl groups. - X is selected from bicarbonate, carbonate, acetate, hydroxide, halide (wherein the halide is preferably selected from chloride and bromide), hydrogen sulfate, alkyl sulfate (wherein the alkyl sulfate is preferably selected from methyl sulfate and ethyl sulfate).

[0096] Even more preferably, Q2 has the general structure R 1 R 2 R 3 R 4 NX, wherein R 4 different from a benzyl residue, and R 1 to R 4 such that the total number of carbon atoms in the quaternary ammonium cation is 6 to 14, preferably 7 to 14, more preferably 8 to 13, or R 4 is a benzyl residue, and R 1 to R 3 such that the total number of carbon atoms in the quaternary ammonium cation is 6 to 12, preferably 7 to 12, more preferably 8 to 11.

[0097] BCC3 comprises a base B3 and a quaternary ammonium ion Q3, wherein the base B3 has a pK b value of < 1 at 25 °C, and wherein Q3 comprises an ammonium cation comprising 15 to 30 carbon atoms, preferably 15 to 28, more preferably 15 to 24, even more preferably 16 to 22, most preferably 16 to 20 carbon atoms.

[0098] More preferably, Q3 has the general structure R 1 R 2 R 3 R 4 NX, wherein - R 1 and R 2 are the same or different and are an alkyl group having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, particularly preferably 1 to 5, most preferably 1 to 4 carbon atoms, wherein the alkyl group can be linear, branched, cyclic, saturated or unsaturated, most preferably a linear, saturated alkyl group, - R 3 is selected from an alkyl group having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, particularly preferably 1 to 5, most preferably 1 to 4 carbon atoms, an aryl group having 6 to 14, preferably 6 to 12, most preferably 6 to 10 carbon atoms, and an aralkyl group having 7 to 14, preferably 7 to 12, most preferably 7 to 10 carbon atoms, wherein the alkyl group can be linear, branched, cyclic, saturated or unsaturated, most preferably a linear, saturated alkyl group, and - R 4The alkyl group is selected from alkyl groups having 3 to 12, preferably 3 to 10, more preferably 3 to 7, and most preferably 4 to 6 carbon atoms; aryl groups having 6 to 14, preferably 6 to 12, and most preferably 6 to 10 carbon atoms; and aralkyl groups having 7 to 14, preferably 7 to 12, and most preferably 7 to 10 carbon atoms, wherein the alkyl group can be linear, branched, cyclic, saturated, or unsaturated, and most preferably linear or saturated. - X is selected from carbonate, bicarbonate, acetate, hydroxide, halide (wherein the halide is preferably selected from chloride and bromide), hydrogen sulfate, and alkyl sulfate (wherein the alkyl sulfate is preferably selected from methyl sulfate and ethyl sulfate).

[0099] 4.4 Crude product R H As a result of step a, crude product R is obtained. H The crude product R H Contains polyol P PU Amine A PU Water (W) and at least one alkali (B).

[0100] The crude hydrolysis product R H Contains organic phase P O and aqueous phase P W .

[0101] In a preferred embodiment, the organic phase P O Includes the crude product R during step a. H A portion of the polyol P formed PU The main part and step a during which the crude product R is produced H A portion of the amine A formed PU The main part.

[0102] During step a, the crude product R is... H A portion of the polyol P formed PU The "main part" specifically refers to the crude product R during step a. H A portion of the polyol P formed is >50 mol%, preferably at least 60 mol%, more preferably at least 70 mol%, more preferably at least 80 mol%, more preferably at least 90 mol%, more preferably at least 99 mol%, or even more preferably substantially all of the polyol P. PU .

[0103] During step a, the crude product R is... H A portion of the amine A formed PU The "main part" specifically refers to the crude product R during step a.H at least 70 mole %, more preferably at least 80 mole %, more preferably at least 90 mole %, more preferably at least 99 mole %, even more preferably essentially all of the amine A PU .

[0104] The aqueous phase P W consists essentially of water W and base B, while the organic phase P H contains, in addition, at least a part of the crude product R O usually also contains water W and base B to some extent, due to the Nernst distribution law, according to which any compound will always be distributed between two immiscible phases.

[0105] In particular, at least 75 wt.-%, preferably at least 95 wt.-% of the water W contained by the crude product R H after step a form the aqueous phase P W part of it, while the organic phase P O also contains water W and comprises at least 25 wt.-%, preferably at least 50 wt.-% of the base B contained by the crude product R H after step a.

[0106] In particular, at least 75 wt.-% of the base B contained by the crude product R H after step a form the aqueous phase P W part of it, while the organic phase P O comprises at least 25 wt.-%, preferably at least 50 wt.-% of the base B contained by the crude product R H after step a.

[0107] In those cases where a phase transfer catalyst is used in step a, in particular if at least one quaternary ammonium salt Q is used in step a, the organic phase P O in particular also contains at least a part of the quaternary ammonium salt Q or decomposition products D formed from Q during the reaction according to step a Q .

[0108] In particular, the aqueous phase P W contains the major part of the base B contained by the crude product R H after step a.

[0109] The process according to the application will lead to an effective hydrolytic cleavage of the urethane bonds and urea bonds present in the PU treated, to produce the amine A PU and the polyol P PU , wherein P PUPreferably polyether polyols. Additional products can also be obtained, especially in those cases where chain extenders or curing agents are used to prepare the PU, such as low molecular weight glycols, diols different from the polyols P PU , diamines different from the amines A PU .

[0110] Also, since the process according to the present application can be applied to recycle PU from a wide range of sources and waste, the PU subjected to the process of the present application can contain additional additives and processing aids, which are subsequently present in the hydrolysis crude product R H obtained after step a, in particular in the organic phase P H and in the aqueous phase P O contained by the crude product R W obtained after step a.

[0111] In a particular embodiment of the present application, the crude product R H obtained after step a thus contains at least one component C, wherein C is selected from the group consisting of foam catalysts, inorganic fillers, polymeric fillers, flame retardants, carboxylates (such as formates, acetates), polydimethylsiloxanes, organic pigments, polymeric fillers (preferably SAN polymers).

[0112] Typically, foam catalysts, inorganic fillers, polymeric fillers, organic pigments are present in the organic phase P O , while carboxylates (such as formates, acetates), polydimethylsiloxanes, inorganic fillers, polymeric fillers (preferably SAN polymers), flame retardants are present in the aqueous phase P W .

[0113] Thus, in a preferred embodiment, (i) said organic phase P H contained by the crude product R O obtained after step a further contains one or more components C O , said components C O are selected from the group consisting of foam catalysts, inorganic fillers, polymeric fillers, organic pigments, antioxidants, dyes, and / or (ii) said aqueous phase P H contained by the crude product R W obtained after step a further contains one or more components C W , said components C W are selected from the group consisting of dyes, polydimethylsiloxanes, polymeric fillers, inorganic fillers, flame retardants, carboxylates, wherein said carboxylates are preferably at least one of formates, acetates.

[0114] In the case of the preferred embodiment (ii), and even more preferably, in accordance with step b from R H P separation O1 Before, during, or after, or even more preferably before or after, at least a portion, preferably all of the said component C will be... W From aqueous phase P W Separation in the middle makes P W Component C in W Minimize the quantity, preferably P W Basically contains no component C W .

[0115] In the preferred embodiment (i), and even more preferably, according to step b from R H P separation O1 Before, during, or after, or even more preferably before or after, at least a portion, preferably all of the said component C will be... O From organic phase P O Separation in the middle makes P O1 Component C in O Minimize the quantity, preferably P O1 Basically contains no component C O .

[0116] In some embodiments, particularly in those where the PU undergoing step a is only partially hydrolyzed in step a, the crude product may also contain solids S. These solids S may be particles of the partially hydrolyzed PU, or additional polymer fillers (e.g., styrene-acrylonitrile polymers, abbreviated as "SAN polymers"), for example in those where the PU is composed of polyols, particularly polyether polyol building blocks, containing such polymers (SAN polymers) in dispersed or covalently bonded form.

[0117] Therefore, the crude product R obtained after step a H Optionally includes solid S.

[0118] In a preferred embodiment, the crude product R H Its composition is as follows: In this preferred embodiment, the crude product R obtained after step a H Organic phase P in O Include, (α) According to organic phase P O The polyol P contains more than 40 wt% by weight, preferably 45 to 90 wt%, more preferably 50 to 80 wt%, even more preferably 55 to 80 wt%, even more preferably 60 to 75 wt%, and most preferably 65 wt%. PU , (β) According to organic phase P OThe amine A comprises 10 to 40 wt%, preferably 15 to 35 wt%, more preferably 20 to 30 wt%, and most preferably 22 to 27 wt% by weight. PU , (γ) according to organic phase P O The amount of water is less than 20 wt%, preferably 0.1 to 15 wt%, more preferably 1 to 10 wt%, even more preferably 3 to 8 wt%, and most preferably 5 wt%. (δ) According to organic phase P O The inorganic base B comprises less than 15 wt% by weight, preferably 0.1 to 10 wt%, more preferably 0.5 to 8 wt%, and most preferably 1 to 5 wt%. (ε) In those cases where at least one quaternary ammonium salt Q is used as a phase transfer catalyst in step a, according to organic phase P O The total weight of the components is <15 wt%, preferably 0 to 10 wt%, more preferably 0.01 to 6 wt%, even more preferably 0.05 to 6 wt%, particularly preferably 0.5 to 4 wt%, and most preferably 1 to 2.5 wt%, consisting of quaternary ammonium salt Q and its decomposition product D. Q It is composed of the sum of D, where D Q It corresponds to amine A. Q and the corresponding alcohol P Q , (ζ) The PU undergoing step a contains the corresponding compound C. O In those cases, according to organic phase P O The total amount of said compound C is less than 15 wt%, preferably 0.1 to 10 wt%, more preferably 0.5 to 8 wt%, and most preferably 1 to 5 wt%. O The compound C O Selected from foam catalysts, inorganic fillers, polymer fillers, organic pigments, antioxidants, and dyes. The sum of the amounts of components (α) to (ζ), plus the amounts of any other optional components, is greater than the organic phase P. O The maximum value is 100wt%.

[0119] Alternatively or additionally, preferably additionally, the crude product R obtained after step a H aqueous phase P W Include, (η) According to aqueous phase P W The amount of polyol P is less than 4 wt%, preferably 0 to 2 wt%, more preferably 0 to 1 wt%, and most preferably 0 to 0.1 wt%. PU , (θ) According to aqueous phase P W0 to 3 wt.-%, preferably 0 to 2 wt.-%, more preferably 0.001 to 1 wt.-%, even more preferably 0.001 to 0.5 wt.-%, most preferably 0.01 to 0.1 wt.-%, based on the weight of the water phase P, of the amine A PU , (ι) 0 to 3 wt.-%, preferably 0 to 2 wt.-%, more preferably 0.001 to 1 wt.-%, even more preferably 0.001 to 0.5 wt.-%, most preferably 0.01 to 0.1 wt.-%, based on the weight of the water phase P, of the amine A W 40 to 80 wt.-%, preferably 45 to 70 wt.-%, more preferably 50 to 60 wt.-%, most preferably 55 to 65 wt.-%, based on the weight of the water phase P, of water W, (κ) 20 to 60 wt.-%, preferably 25 to 50 wt.-%, more preferably 30 to 40 wt.-%, most preferably 35 to 45 wt.-%, based on the weight of the water phase P, of the inorganic base B, (λ) In those cases where at least one quaternary ammonium salt Q is used as phase transfer catalyst in step a, the sum of 0 to 3 wt.-%, preferably 0 to 2 wt.-%, more preferably 0.001 to 1 wt.-%, even more preferably 0.001 to 0.5 wt.-%, most preferably 0.01 to 0.1 wt.-%, based on the weight of the water phase P, is made up of the quaternary ammonium salt Q and the decomposition products D of said quaternary ammonium salt Q, W Q Q Q Q , (μ) In those cases where the PU subjected to step a contains the corresponding compound C W W W W W wherein the compound C is selected from the group consisting of carboxylates (e.g. formates, acetates), polydimethylsiloxanes, polymeric fillers (preferably SAN polymers), flame retardants, dyes, inorganic fillers, wherein the amount of components (η) to (μ) plus the amount of optionally present further components sums up to a maximum of 100 wt.-% of the water phase P.

[0120] In those cases where the quaternary ammonium salt Q has the general structure R 1 2 3 4 Q 1 2 3 1 3 4 ​​​​​​​​​​​​​​​​​​​4 N, R 1 R 2 R 4 N, R 2 R 3 R 4 N, R 1 R 2 NH, R 1 R 3 NH, R 1 R 4 NH, R 2 R 3 NH, R 2 R 4 NH, R 3 R 4 NH, R 1 -NH2, R 2 -NH2, R 3 -NH2, R 4 -NH2, and the corresponding alcohol P Q are preferably selected from R 1 -OH, R 2 -OH, R 3 -OH, R 4 -OH.

[0121] 4.5 Reaction conditions in step a According to the present application, step a is carried out by contacting water W, at least one base B and the PU subjected to the hydrolysis reaction. Such contacting is in particular carried out in a reactor in which the individual reaction components are mixed and react with one another. Such reactors are in particular selected from continuous stirred tank reactors, autoclaves.

[0122] In an alternative embodiment, step a can also be carried out in a reactor specially designed for continuous processing, such as an extruder (e.g. screw extruder, planetary gear extruder), kneader, etc.

[0123] The reaction conditions applied in step a are known to the person skilled in the art.

[0124] Preferably, the at least partial hydrolysis according to step a is carried out at a temperature of from 90°C to 220°C, preferably from 100°C to 200°C, more preferably from 110°C to 200°C, even more preferably from 120°C to 200°C, most preferably from 140°C to 200°C.

[0125] Further preferably, the hydrolysis according to step a is carried out for a period of 30 minutes to 20 hours, preferably 30 minutes to 16 hours, more preferably 30 minutes to 14 hours, even more preferably 45 minutes to 10 hours, particularly preferably 60 minutes to 8 hours, even more preferably 60 minutes to 6 hours.

[0126] Further preferably, the hydrolysis according to step a is carried out at atmospheric pressure or at elevated pressure, particularly at a pressure of 1 to 30 bar absolute pressure, preferably 2 to 20 bar absolute pressure, more preferably 3 to 15 bar absolute pressure.

[0127] 4.6 Pulverization step (optional) In order to facilitate the treatment of the PU in step a, it is preferred to carry out a preceding step (i.e. prior to step a) in which the PU is subjected to at least one pre-treatment by which the PU is comminuted. Such comminution is even more preferably selected from the group consisting of chopping, pulverizing, grinding. By this preferred pre-treatment step, the PU is obtained in the form of relatively small particles or granules. This pre-treatment step is particularly advantageous if the PU subjected to the process of the present application is in solid form. In such cases, a pulverizing step is highly advantageous in order to maximize the surface area available for the reaction, thus reducing the reaction time needed to achieve the desired level of hydrolysis.

[0128] In another preferred embodiment of the present application, particularly if the PU subjected to the process according to the present application is a foam, said PU can be partially or completely compressed prior to subjecting it to step a.

[0129] The progress of the hydrolysis of the PU in step a can be monitored by nuclear magnetic resonance ("NMR") or infrared ("IR") spectroscopy. In particular, these methods can be used to monitor the amount of urethane groups in said PU used in step a, and the amount of urethane groups in said PU after the reaction has been carried out.

[0130] In a preferred embodiment, step a is carried out until the amount of urethane groups in the PU initially subjected to step a has been reduced by at least 10%, more preferably by at least 25%, more preferably by at least 40%, more preferably by at least 51%, more preferably by at least 75%, more preferably by at least 85%, more preferably by at least 92%, more preferably by at least 99%.

[0131] Even more preferably, step a is carried out until the PU groups can no longer be detected substantially.

[0132] 5. Step b According to step b of the process of the present application, at least a part P O of the organic phase P O1 is separated from the crude product R H , wherein P O1 comprises the polyol P PU , the amine A PU , and water W.

[0133] In step b, "separating at least a part P O1 from R H " also comprises the embodiment wherein essentially the entire organic phase P O is separated from the crude product R H comprising the entire aqueous phase P W . In this embodiment, P O1 is essentially identical to P O .

[0134] After step b, the organic phase P H is obtained which is not in direct contact with the remaining part of the crude product R O1 obtained after step a. In other words, the organic phase P O1 is separated from at least a part of the aqueous phase P W obtained after step a.

[0135] The separation of the at least a part P O of the organic phase P O1 from the crude product R H according to step b can be performed according to the knowledge of the skilled person.

[0136] In particular, the separation can be performed in a separatory funnel and / or via centrifugation or via decanting in step b.

[0137] In those cases where the crude product R H contains solids S, it is preferred that at least a part of the solids S comprised by the crude product R O is separated from the crude product R O1 , in particular from at least one phase selected from the organic phase P H and the aqueous phase P H , preferably from the organic phase P H , before or after separating at least a part P O of P W from R O .

[0138] This preferred separation from R H , in particular from at least one phase selected from the organic phase P O and the aqueous phase P WThe separation of solid S from at least one phase can be carried out in accordance with the knowledge of those skilled in the art, particularly by at least one method selected from filtration, decantation, and centrifugation.

[0139] After step b, the crude product R is obtained. H The remaining part of the separated organic phase P O The at least part of P O1 The product after step b is still the crude product R. H The aqueous phase included in this article is abbreviated as "P". W1 ".

[0140] In particular, the organic phase P obtained therefrom O1 The composition corresponds to the crude product R obtained after step a. H Includes organic phase P O The composition of.

[0141] Therefore, in a preferred embodiment, the organic phase P obtained after step b O1 The composition comprises, (α1) According to organic phase P O1 The polyol P contains more than 40 wt% by weight, preferably 45 to 90 wt%, more preferably 50 to 80 wt%, even more preferably 55 to 80 wt%, even more preferably 60 to 75 wt%, and most preferably 65 wt%. PU , (β1) According to organic phase P O1 The amine A comprises 10 to 40 wt%, preferably 15 to 35 wt%, more preferably 20 to 30 wt%, and most preferably 22 to 27 wt% by weight. PU , (γ1) according to organic phase P O1 The amount of water is less than 20 wt%, preferably 0.1 to 15 wt%, more preferably 1 to 10 wt%, even more preferably 3 to 8 wt%, and most preferably 5 wt%. (δ1) According to organic phase P O1 The inorganic base B comprises less than 15 wt% by weight, preferably 0.1 to 10 wt%, more preferably 0.5 to 8 wt%, and most preferably 1 to 5 wt%. (ε1) In those cases where at least one quaternary ammonium salt Q is used as a phase transfer catalyst in step a, according to the organic phase P O1 The total weight of the components is <15 wt%, preferably 0 to 10 wt%, more preferably 0.01 to 6 wt%, even more preferably 0.05 to 6 wt%, particularly preferably 0.5 to 4 wt%, and most preferably 1 to 2.5 wt%, consisting of quaternary ammonium salt Q and its decomposition product D. QIt is composed of the sum of D, where D Q It corresponds to amine A. Q and the corresponding alcohol P Q , (ζ1) The PU undergoing step a contains the corresponding compound C. O In those cases, according to organic phase P O1 The total amount of compound C is less than 15 wt%, preferably 0.1 to 10 wt%, more preferably 0.5 to 8 wt%, and most preferably 1 to 5 wt%. O The compound C O Selected from foam catalysts, inorganic fillers, polymer fillers, organic pigments, antioxidants, and dyes. The sum of the amounts of components (α1) to (ζ1) plus any other optionally included components is greater than the organic phase P. O1 The maximum value is 100wt%.

[0142] Importantly, the P obtained after step b O1 It still contains water. This logically means that, correspondingly, the product R after step a is the crude product. H A portion of the P obtained O It must also contain water. This is due to the Nernst distribution law, according to which, although R... H The main part of the water in it naturally forms the aqueous phase P. W However, water can also exist in the organic phase P. O middle.

[0143] Furthermore, P after step b O1 The water (and base B) contained may also be due to their separation from the aqueous phase P during phase separation. W This is caused by the phase being carried out, and is therefore due to an imprecise separation method. Such slight imprecisions in phase separation can be minimized, but not always completely avoided, although it is preferable to implement P in step a. O1 From R H The clear and precise separation in the text.

[0144] Preferably, the separation is performed by at least one separation method selected from centrifugation, filtration, decantation, and membrane processes.

[0145] The method of the present invention is advantageous in several respects, one of which is its resource efficiency. To further improve this resource efficiency, the method according to the invention is characterized in a preferred aspect by wherein, according to step b, P... O1 From R H After separation, it will be handled by R. H Includes aqueous phase P W At least a portion of it is used in the hydrolysis according to step a.

[0146] In particular, it will be composed of aqueous phase P W1 The aqueous phase P contains at least a portion of water and / or at least a portion of base B for use in the hydrolysis of step a. W1 In step b, P is... O1 From R H Obtained after separation.

[0147] For example, P in step b O1 From R H R obtained after separation H Includes aqueous phase P W1 At least a portion of it can be fed into the hydrolysis reaction mixture, wherein hydrolysis is carried out according to step a.

[0148] In use from P W1 In an alternative embodiment of the recycled water and alkali B, the aqueous phase may also undergo distillation, and the water thus distilled is fed into the hydrolysis in step a, and / or by means of the water from the corresponding phase P. W1 Crystallization can obtain P W1 It contains base B. In this way, it is achieved from P... W1 Water and base B are recovered separately, which allows water and base B to be fed into the reaction mixture according to step a independently, and also allows the amount of either compound to be metered independently.

[0149] 6. Step c According to step c of the method of the present invention, distillation is performed from P O1 At least a portion of water W and amine A are separated in the middle. PU At least a part of it.

[0150] In a preferred embodiment of step c, distillation is performed from P O1 Amine A (separated from amine) PU A portion of and at least a portion of water W.

[0151] After performing step c, water vapor V is obtained, containing amine A. PU fraction F A and containing polyol P PU Optional amine A PU And the organic phase P of water W which is present by choice O2 "Contains polyol P" PU Optional amine A PU And the organic phase P of water W which is present by choice O2 "This should be understood as organic phase P" O2 Contains polyol P PU The organic phase P O2 Optionally includes amine A PUAnd the organic phase P O2 Water (W) may be included optionally.

[0152] Preferably, P O2 Contains polyol P PU Amine A PU And the water W that exists at will.

[0153] Distillation step c can be performed according to the knowledge of those skilled in the art. The basic requirement is that after step c, the water vapor V and the distillate F... A and organic phase P O2 As separate phases, they are obtained, meaning they do not come into direct contact with each other.

[0154] In a preferred embodiment, step c comprises at least two distillation steps c1 and c2, wherein in step c1, distillation is performed from P... O1 At least a portion of the water W is separated to obtain water vapor V and residual organic phase. And in step c2, the distillation is performed from... Amine A (separated from amine) PU At least a portion, preferably a portion, to obtain fraction F A and residual organic phase P O2 .

[0155] In step c, particularly in step c1, "water vapor V" is obtained. Therefore, the water preferably contains the at least one amine A. PU Compared to a lower boiling point. Preferably, the distillation according to step c1 is carried out at a temperature T. c1 ≤ 220℃, preferably T c1 ≤200℃ and pressure p c1 ≤ 1 bar absolute pressure, preferably 0 <p c1 ≤ 1000 mbar absolute pressure, more preferably 1 ≤ p c1 ≤500 mbar absolute pressure, optimally 20 ≤p c1 Performed under an absolute pressure of ≤ 300 mbar.

[0156] Alternatively or additionally, preferably additionally, preferably, in step c, particularly in step c2, a substance containing amine A is obtained. PU fraction F A Therefore, the at least one amine A PU Preferably, it has a composition similar to the at least one polyol P. PU Compared to a lower boiling point. Preferably, the distillation according to step c2 is carried out at a temperature T. c2 ≤ 220℃, preferably T c2 ≤ 200℃ and pressure p c2 ≤ 1 bar absolute pressure, preferably 0 <p c2≤ 1000 mbar absolute pressure, more preferably 0 ≤ p < 1000 mbar absolute pressure c2 ≤ 100 mbar absolute pressure, most preferably 0 ≤ p < 100 mbar absolute pressure c2 ≤ 20 mbar absolute pressure.

[0157] During step c2, it is preferred that the distillation temperature is higher compared to the distillation temperature during step cl, and that the distillation pressure during step c2 is equal or lower compared to the distillation pressure during step cl, thus: preferably T c1 < T c2 and p c1 ≥ p c2 .

[0158] These conditions are particularly advantageous in case the at least one amine A PU has the general structure of formula (II): H2N-W 1 -NH2, wherein W 1 has the structure (II-B) as described above, preferably wherein the at least one amine A PU is toluenediamine (“TDA”).

[0159] The composition of the residual organic phase P obtained after step cl and subjected to step c2, in particular the composition corresponding to P O1 subjected to step cl, wherein the amount of water comprised by P is lower compared to the amount of water comprised by P O1 . Optionally, the amount of amine A PU comprised by P O1 is lower compared to the amount of amine A PU comprised by P .

[0160] The composition of the residual organic phase P O2 obtained after step c2 and subjected to step d, in particular the composition corresponding to P subjected to step c2, wherein the amount of amine A O2 comprised by P PU is lower compared to the amount of amine A PU comprised by P . Optionally, the amount of water comprised by P O2 is lower compared to the amount of water comprised by P .

[0161] In particular, step cl is at least partially performed in a distillation column K1.

[0162] Any desired distillation column known to the person skilled in the art can be used as distillation column K1 (or as distillation column K2 described below) in the preferred embodiment of step c. Said distillation column K1 and said distillation column K2 preferably contain internals. Suitable internals are, for example, trays, unstructured packings or structured packings. The trays used are typically bubble cap trays, sieve trays, float valves, tunnel-cap trays or slotted trays. Structured packings are usually beds of random packing elements. The random packing elements used are typically Raschig rings, Pall rings, Berl saddle packings or Intalox ® saddle packings. Structured packings are sold, for example, under the trade name Sulzer Mellapak ® In addition to the mentioned internals, other suitable internals are known to the person skilled in the art and can likewise be used.

[0163] In another preferred embodiment, step c2 is carried out at least partially in at least one apparatus selected from the group consisting of short path evaporators, thin-film evaporators, distillation columns K2, wherein the distillation columns K2 are different from the distillation column K1.

[0164] In a preferred embodiment, the at least one amine A PU has a boiling point which is higher than the boiling point of water, and the at least one polyol P PU has a boiling point which is higher than the boiling point of the at least one amine A PU .

[0165] In those embodiments in which P O1 contains the quaternary ammonium salt Q and / or the decomposition products D Q of the quaternary ammonium salt Q, it is preferred that these are separated from P O1 in an additional distillation step and / or with water vapor W. In particular, in those embodiments in which P O1 contains the quaternary ammonium salt Q and / or the decomposition products D Q of the quaternary ammonium salt Q and steps cl and c2 are carried out, it is preferred that at least a portion of the quaternary ammonium salt Q and / or the decomposition products D Q of the quaternary ammonium salt Q are separated during step cl, i.e. after or simultaneously with the water vapor V, by distillation, more preferably the decomposition products D Q of the quaternary ammonium salt Q.

[0166] In those cases in which the water vapor V obtained after step cl is contaminated with the quaternary ammonium salt Q and / or the decomposition products D Q of the quaternary ammonium salt Q, it is preferred that it is subjected to an additional distillation step before it is used as stripping gas in step d.

[0167] Preferably, step c, particularly at least a portion of step c2, is carried out in an atmosphere having an oxygen content of 0 to 21% by volume, preferably 0 to 8% by volume, more preferably 0 to 1% by volume, and most preferably 0 to 0.1% by volume, and preferably in an atmosphere containing only product vapor and one or more inert gases.

[0168] This further improves the recycling of amine A. PU and recycled polyol P PU The purity of these materials makes them particularly suitable for recycling in the production of PU.

[0169] 7. Step d According to step d of the method of the present invention, the organic phase P is purified by stripping. O2 At least a portion of P O3 The method of the present invention is characterized in that, in step d, water vapor V is used as a relative to P. O3 The stripping gas in the countercurrent.

[0170] Because of this program, it is possible to use P O1 The water separated from the steam does not require the addition of additional water for this stripping step d.

[0171] The stripping step d is advantageous because it further purifies the organic phase P obtained after step c, especially after step c2. O2 At least a portion of P O3 In a preferred embodiment, the phase P O2 Still contains amine A PU and / or quaternary ammonium salt Q and / or decomposition product D Q In particular, P O2 Still contains amine A PU P O2 These impurities are at least partially, and preferably completely, removed in step d.

[0172] "Stripping" is a physical separation process known to those skilled in the art and is used in many areas of the prior art for purifying liquids (as described, for example, in M. Kriebel: "Absorption, 2. Design of Systems and Equipment", Ullmann's Encyclopedia of Industrial Chemistry, Electronic Release, chap. 3, Wiley VCH, Weinheim October 2008).

[0173] In the context of this invention, the gas phase, i.e., water vapor V, and the phase to be purified, i.e., PO3 , the phase to be purified, i.e. P O3 , is contacted with the water vapor V in countercurrent manner at a reduced pressure of < 1 bar. According to the application, this contacting takes place in particular in a distillation column, more preferably in column K1 in those cases where column K1 is used in step c.

[0174] In the present application, the stripping is preferably carried out at a reduced pressure of < 1 bar. Optionally, in addition to the water vapor V, a further inert stripping gas can also be used in countercurrent manner. This further inert stripping gas is preferably selected from the group consisting of noble gases, nitrogen. Likewise, in addition to the water vapor V obtained in step c, additional water vapor can also be used in step d in order to further improve the purification of P O3 .

[0175] The temperature of the stripping can be adjusted by the person skilled in the art by setting the appropriate underpressure in the column conventionally.

[0176] The pressure in step d according to the application is preferably < 1 bar absolute pressure, in particular in the range from 1 to 500 mbar absolute pressure, more preferably in the range from 20 to 300 mbar absolute pressure.

[0177] Step d is preferably carried out at a temperature of < 250°C, preferably < 200°C.

[0178] In particular, the organic phase P O3 is used in step d at a temperature of < 200°C, preferably 150°C to 200°C, while the water vapor V is used in step d at a temperature of < 250°C, preferably 180°C to 200°C.

[0179] The purification of P O3 in step d can be improved by increasing the surface area of column K1 in the sections in which P O3 and the water vapor V are contacted during the stripping. Preferably, for this purpose, P O3 in step d of the process according to the application is at least partially passed through a bed of packing elements or through structured packing within column K1. Suitable for this purpose are all packing elements and structured packings known to the person skilled in the art from the prior art for distillation and for absorption processes. Alternatively, the stripping can be carried out in a falling-film or thin-film evaporator. These devices are known to the person skilled in the art from the prior art.

[0180] Preferably, step d and at least a part of step c are carried out in the same distillation column K1. In those embodiments in which step c comprises step c1 and step c2, it is further preferred that step c1 and step d are carried out in the same distillation column K1.

[0181] In this preferred embodiment, the resource efficiency is even more improved, since only one column K1 is used for both steps c and d. Furthermore, the water vapor obtained in step c can be conducted within column K1 towards the column top of column K1, so that no condensation and evaporation of water vapor V is needed. Then, P O3 is fed from the column top of column K1.

[0182] The organic phase P O3 comprising at least one amine A PU , amine decomposition products D Q of amine A is subjected to step d. O3 The amount of all amine A in P A is reduced to < 5 wt.-%, preferably < 1 wt.-%, more preferably < 0.5 wt.-%, even more preferably < 0.3 wt.-%, most preferably < 0.1 wt.-%, during step d.

[0183] 8. Optional purification step In a preferred embodiment, the process according to the present application comprises at least one further step e, in which the fraction F O3 obtained after step c is further purified and / or the organic phase P A obtained after step d is further purified.

[0184] The optionally present step e is preferably selected from the group consisting of filtration, fractional distillation, crystallization, membrane processes, solvent extraction.

[0185] In particular, in step e, at least one impurity selected from the group consisting of water, polyols and lighter alcohols, catalyst decomposition products, amine oxidation products, fillers, additives, preferably pigments and colorants, and impurities from the production of PU foams, is removed from F O3 and / or P PU respectively.

[0186] 9. Recycling step The process according to the present application is a resource-efficient process which gives polyols P PU and amines A PU in high purity. Thus, any compound obtained in the process is efficiently recycled and can be used for the synthesis of PU.

[0187] Then, preferably, at least one of these compounds selected from polyols P PU and amines A AThe amine A obtained in step d PU In an additional step f the following reaction is subjected to, in which the amino group of the amine A PU is converted into an isocyanate group, preferably via phosgenation. Such phosgenations are known to the person skilled in the art, for example in R.J. Slocombe, E.E. Hardy, J.H. Saunders, R.L. Jenkins, J. Am. Chem. Soc. 1950, 72 , 1888-1891 & H.J. Twitchett, Chem. Soc. Rev. 1974, 3 , 209-230.

[0188] A further preferred aspect of the present application is the use of the polyol P obtained in the process according to the present application, in particular step d PU and / or the isocyanate obtained in step f for the production of polyurethanes, in particular polyurethane foams.

[0189] Even more preferred is the use of the polyol P obtained in the process according to the present application, in particular step d PU and the isocyanate obtained in step f for the production of polyurethanes, in particular polyurethane foams. In this even more preferred embodiment, it is most preferred that the polyol P obtained in the process according to the present application, in particular step d PU and the isocyanate obtained in step f are polymerized with each other to produce polyurethanes, in particular polyurethane foams.

[0190] Example 1. Hydrolysis reaction PU scrap containing polymers of 2,4- and 2,6-toluene diisocyanate with a polyether polyol which is a polymer of ethylene oxide with 1,2- and 1,3-propylene oxide is comminuted in a comminutor.

[0191] Then, 10 kg of these PU particles are mixed with 97.3 kg of a 40 wt% aqueous K2C03 solution and 0.956 kg of tetrabutylammonium hydrogen sulfate in a steel kettle. The resulting mixture is heated to 150°C and stirred for 4 hours. The thus obtained crude product is left to cool to room temperature. It contains a solid, an aqueous phase and an organic phase. The organic phase is left to settle in the reactor and then it is separated from the aqueous phase and the solid.

[0192] The organic phase contains ~ 5 wt% water, ~ 22 wt% TDA and ~ 65 wt% polyether polyol.

[0193] 2.Treatment of the organic phase The organic phase is treated by distillation in the apparatus shown in the drawing.

[0194] In particular, the organic phase is fed as stream <1> into an evaporator <2> connected to a distillation column <4>. The distillation column <4> comprises two packing zones <41>, <44> and a liquid collector <45> at the bottom of the upper packing zone <44>.

[0195] In the evaporator <2> the organic phase is heated to 200°C while the pressure in the column <4> is 50 to 200 mbar absolute. In the column <4> water vapor <3> passes through the lower packing zone <41> and is partially condensed in a condenser <42> within the column <4> so that impurities in the water vapor, in particular lower boiling compounds and higher boiling compounds such as TDA or amine decomposition products of the phase transfer catalyst (e.g. tributylamine, "TriBA"), are separated from the water vapor by condensation and are withdrawn via line <7>. In addition, part of the condensate is recycled via feed <14> through a heater <9> into the column <4>. Additional water can be fed into this reflux via line <8>. The water vapor <3> is optionally heated (e.g. by heating means <43> in the column <4>) and passes through the upper packing zone <44>.

[0196] The liquid distillation residue <5> remaining in the evaporator <2> is then conducted to a short film evaporator (not shown in the drawing) in which TDA is removed from <5> by distillation at 190°C and 4 mbar absolute.

[0197] The liquid distillation residue <6> remaining from this second distillation in the short film evaporator mainly comprises polyols. After heating it to 160°C in a preheater <10> it is fed to the top of the column <4>. In the upper part of the column <4> the organic phase <6> is stripped with water vapor <3> in countercurrent fashion. This final stripping step essentially removes impurities, such as amine compounds, in particular TDA and TriBA, from the polyol phase <6>. A high purity polyol <11> is then obtained. The water vapor containing impurities from the polyol phase <6> is then withdrawn at the top of the column <4> as stream <13>. This water vapor can be condensed via a condenser <12> and fed via line <8> to the column <4>, preferably after further cleaning to remove impurities.

[0198] 3. Advantages compared to prior art processes Compared to prior art processes, in which the distillation of water / amine such as TDA / stripping of polyol phase is carried out separately or even not specifically described in detail, this procedure offers several advantages. In the process according to the present application, the final purification step, i.e. the stripping, which is required to obtain a highly purified polyol phase, is carried out in a resource-efficient manner. The polyol phase obtained thereby is very pure, so that the polyol can be directly used for polymerization with isocyanate to obtain polyurethane PU.

[0199] 3.1 ) The water evaporated from the organic phase <1 > is directly used for the stripping of the organic phase <6>. Thus, no additional water needs to be provided to the process. Said feed <8> is completely optional and not necessary for achieving the advantageous effect.

[0200] 3.2) The water vapor <3> obtained in the first distillation step can be directly used for the stripping of the organic phase <6> as it is already in the "right" state of aggregation, i.e. gaseous. Thus, the present process does not require energy for condensing / evaporating water.

[0201] 3.3) The process can be carried out in one column, which makes it even more advantageous as it also saves equipment as only one column <4> is available for both distillation steps.

Claims

1. A polyol P used to produce at least one recycled polyol P from at least one polyurethane PU PU and at least one recycled amine A PU The method, The method includes the following steps: a. By contacting the PU with water W and at least one alkali B, the PU is at least partially hydrolyzed. To obtain crude product R H The crude product R H Contains polyol P PU Amine A PU Water W, at least one base B, and optionally present solid S, The crude product R H Contains organic phase P O and aqueous phase P W , b. The organic phase P O At least a portion of P O1 From the crude product R H Separation in the middle, where P O1 Contains polyol P PU Amine A PU Water W, c. Distilling at least a portion of the water W and the amine A PU At least a portion of P O1 Separation in the middle, To obtain: -Water vapor V, -Fractions F A The fraction F A Contains amine A PU , -Organic phase P O2 The organic phase P O2 Contains polyol P PU Optional amine A PU And the water W that exists at will, d. Purification of the organic phase P by stripping O2 At least a portion of P O3 , Its features are, In step d, water vapor V is used as a function relative to P. O3 The stripping gas in the countercurrent.

2. The method according to claim 1, characterized in that... The at least one base B is selected from the following: alkali metal phosphates, alkaline earth metal phosphates, alkali metal hydrogen phosphates, alkaline earth metal hydrogen phosphates, alkali metal carbonates, alkaline earth metal carbonates, alkali metal silicates, alkaline earth metal silicates, alkali metal bicarbonates, alkaline earth metal bicarbonates, alkali metal carboxylates, alkaline earth metal carboxylates, alkali metal sulfites, alkaline earth metal sulfites, ammonium hydroxide, alkali metal hydroxides, alkali metal oxides, alkaline earth metal oxides, and alkaline earth metal hydroxides.

3. The method according to claim 1 or 2, characterized in that... The hydrolysis in step a is catalyzed by at least one phase transfer catalyst selected from quaternary ammonium salts Q and organic sulfonates / salts. Preferably, the quaternary ammonium salt Q has the general formula R. 1 R 2 R 3 R 4 NX, where R 1 R 2 R 3 and R 4 They may be the same or different, and each is a hydrocarbon group selected from alkyl, aryl, arylalkyl, and X is selected from hydroxide, carbonate, bicarbonate, bisulfate, carboxylate, halide, alkyl sulfate.

4. The method according to any one of claims 1 to 3, characterized in that, According to step b, P O1 From R H After separation, it will be handled by R. H The aqueous phase P included W At least a portion of it is used in the hydrolysis according to step a.

5. The method according to any one of claims 1 to 4, characterized in that, (i) From the crude product R H The organic phase P contained therein O Further includes one or more components C O The component C O Selected from foam catalysts, inorganic fillers, polymer fillers, organic pigments, antioxidants, and dyes. And / or, (ii) From the crude product R H The aqueous phase P included W Further includes one or more components C W The component C W Selected from carboxylic acid esters / salts, polydimethylsiloxane, inorganic fillers, polymer fillers, flame retardants, and dyes.

6. The method according to any one of claims 1 to 5, characterized in that... Step c comprises at least two distillation steps c1 and c2, wherein in step c1, the product is distilled from P... O1 At least a portion of the water W is separated to obtain water vapor V and a residual organic phase. And in step c2, the distillation is performed from... The amine A was separated from the middle PU At least a portion, to obtain fraction F A and residual organic phase P O2 .

7. The method according to claim 6, characterized in that... Step c1 is carried out at least in part in distillation column K1.

8. The method according to claim 6 or 7, characterized in that... Step c2 is carried out at least in part in at least one device selected from a short-path evaporator, a thin-film evaporator, and a distillation column K2, wherein the distillation column K2 is different from the distillation column K1.

9. The method according to any one of claims 6 to 8, characterized in that, - Distillation according to step c1 at temperature T c1 ≤ 220℃, preferably T c1 ≤ 200℃ and pressure p c1 ≤ 1 bar absolute pressure, preferably 0 < p c1 ≤ 1000 mbar absolute pressure, more preferably 1 ≤ p c1 ≤ 500 mbar absolute pressure, optimally 20 ≤ p c1 Performed under an absolute pressure of ≤ 300 mbar. and - Distillation according to step c2 at temperature T c2 ≤ 220℃, preferably T c2 ≤ 200℃ and pressure p c2 ≤ 1 bar absolute pressure, preferably 0 < p c2 ≤ 1000 mbar absolute pressure, more preferably 0 ≤ p c2 ≤ 100 mbar absolute pressure, optimally 0 ≤ p c2 The test was conducted at an absolute pressure of ≤ 20 mbar. And preferably T c1 < T c2 And p c1 ≥ p c2 .

10. The method according to any one of claims 1 to 9, characterized in that... Step c, preferably at least a portion of step c2, is carried out in an atmosphere containing 0 to 21% by volume of oxygen, preferably 0 to 8% by volume, more preferably 0 to 1% by volume, most preferably 0 to 0.1% by volume, and preferably the atmosphere contains only product vapor and one or more inert gases.

11. The method according to any one of claims 1 to 10, characterized in that... At least a portion of step d and step c, preferably at least a portion of step c1, are carried out in the same distillation column K1.

12. The method according to any one of claims 1 to 11, characterized in that... The hydrolysis according to step a proceeds in at least a partial manner as follows: At a temperature of 90°C to 220°C, preferably 100°C to 200°C, more preferably 120°C to 200°C, and most preferably 140°C to 200°C, and / or The duration is from 30 minutes to 20 hours, preferably from 30 minutes to 16 hours, more preferably from 30 minutes to 14 hours, even more preferably from 45 minutes to 10 hours, particularly preferably from 60 minutes to 8 hours, and most preferably from 60 minutes to 6 hours. and / or At atmospheric pressure or under elevated pressure, particularly at 1 to 30 bar absolute pressure, preferably 2 to 20 bar absolute pressure, and more preferably 3 to 15 bar absolute pressure.

13. The method according to any one of claims 1 to 12, characterized in that... It includes at least one further step e, in which the fraction F obtained after step c is... A Further purification and / or purification of the organic phase P obtained after step d O3 Further purification, wherein step e is preferably selected from filtration, fractionation, crystallization, membrane process, and solvent extraction.

14. The method according to any one of claims 1 to 13, characterized in that, In step f, from fraction F A Amine A PU The amine A undergoes the following reaction, in which it is converted into an amino acid A. PU The amino group is converted into an isocyanate group, preferably via phosgenation.

15. For use with at least one recycled polyol P PU A method for producing polyurethane, particularly polyurethane foam, the method comprising the following steps: (1) The method according to any one of claims 1 to 13 to produce at least one recycled polyol P PU , (2) Optionally, isocyanates are produced according to the method of claim 14. (3) Recycling at least one of the polyols P PU It reacts with isocyanate, preferably with isocyanate from step (2).

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