Method for recovering raw materials from polymer compositions containing polyester-polyurethane elastomers

Abstract

The invention relates to a method for recovering raw materials from a polymer composition containing a polyester-polyurethane elastomer, comprising the following steps: (A) providing a polymer composition, the present invention relates to a polymer composition comprising a polyester-polyurethane elastomer based on (i) a polyester component, (ii) an isocyanate component, and optionally (iii) a chain extender and / or a cross-linking agent having hydroxyl and / or amine functional groups wherein the polymer composition comprises a first polyester-polyurethane elastomer whose isocyanate component comprises a naphthalene-1, 5-diisocyanate; (B) reacting the polymer composition with a linear primary monoalcohol having 1 to 4 carbon atoms to obtain a product mixture comprising a liquid alcohol phase and a solid urethane phase; and (C) separating the carbamate from the product mixture.

Description

[0001] The present invention relates to a method for recovering raw materials from a polymer composition containing a polyester-polyurethane elastomer, comprising the steps of: (A) providing a polymer composition comprising a polyester-polyurethane elastomer based on (i) a polyester component, (ii) an isocyanate component and optionally (iii) a chain extender and / or a crosslinker having hydroxyl and / or amine functional groups, wherein the polymer composition comprises a first polyester-polyurethane elastomer whose isocyanate component comprises naphthalene-1,5-diisocyanate; (B) reacting the polymer composition with a linear primary monohydric alcohol having 1 to 4 carbon atoms to obtain a product mixture comprising a liquid alcohol phase and a solid carbamate phase; and (C) separating the carbamate from the product mixture.

[0002] Polyurethanes are widely used in industry and everyday life. In the case of polyurethanes, a distinction is usually made between polyurethane foams and so-called "CASE" products, where "CASE" is a general term for polyurethane coatings (e.g. paints), adhesives, sealants and elastomers. Polyurethane foams are usually divided into rigid foams and flexible foams. Despite the differences between these products, what they all have in common is the polyurethane basic structure, which is formed by polyaddition reactions of multifunctional isocyanates and polyols. For example, for a polyurethane based on a diisocyanate O=C=NRN=C=O and a diol HO-R'-OH (where R and R' represent organic groups), its structure can be expressed as

[0003] ~~~[O-R'-O-(O=C)-HN-R-NH-(C=O)]~~~.

[0004] Many polyurethanes contain other structural units in addition to the polyurethane base structure, including in particular urea, isocyanurate, allophanate and biuret structural units.

[0005] Because polyurethane has achieved great success economically, it has also produced a large amount of polyurethane waste, which must be effectively utilized. The simplest recycling method for implementation in technology is combustion, wherein the heat released by combustion is used for other processes, such as industrial manufacturing processes. However, this method cannot achieve a closed-loop circulation of raw materials. Another recycling method is so-called "physical recycling", in which polyurethane waste is mechanically crushed and used to produce new products. This recycling method naturally has its limitations, so people have carried out a large number of attempts to reclaim the raw materials based on polyurethane production by re-cracking urethane bonds (and optionally existing bond structures, such as isocyanurate bonds, urea bonds, allophanate bonds or biuret bonds) (so-called "chemical recycling"). The raw materials to be recycled mainly include polyols (HO-R'-OH in the above example) or their degradation products (monomers based on polyester polyols, for example). Furthermore, amines can also be obtained by hydrolytic cleavage of the amino bond (H2N-R-NH2 in the above example), which can be phosgenated to isocyanates (O=C=NRN=C=O in the above example) after workup.

[0006] In the past, a variety of chemical recovery methods have been developed. The three most important methods are briefly summarized below:

[0007] 1. Hydrolysis of the urethane by reaction with water to give amines and polyols, and formation of carbon dioxide.

[0008] 2. The urethane is subjected to a diollysis by reaction with an alcohol, wherein the polyol incorporated into the urethane group is replaced by the alcohol used, thereby releasing the polyol. This process is generally referred to in the literature as transesterification (more precisely: transurnesterification). Regardless of the specific nature of the alcohol used, this mode of chemical recovery is generally referred to in the literature as diollysis, although this term is actually only applied to diols or diol derivatives. (Thus, in the present invention, it is generally referred to as "alcoholysis.") The diollysis can be followed by a hydrolysis. If the hydrolysis is carried out using the direct process product of the diollysis (i.e. without prior separation of the polyol and the urethane), it is called

[0009] 3. Hydrodiolization of the urethane bond by reaction with alcohol and water. Of course, alcohol and water can also be added from the beginning, in which case the diolization and hydrolysis processes are carried out simultaneously.

[0010] The article "Methanolysis Investigation of Commercially Available Polyurethane Foam" by N. Asahi et al., published in Polymer Degradation and Stability 2004, 86, 147–151, describes the methanolysis of polyurethane at temperatures ranging from 160 to 300°C and pressures up to 15 MPa, with the methanol partially in a supercritical state. The goal of this study was to perform methanolysis on commercially available polyurethane foam without the use of a catalyst. The study examined:

[0011] Chemical decomposition of model polyurethane 1,

[0012] and commercially available polyurethane foam Chemical decomposition at a methanol to polyurethane mass ratio of 5:1 or 16:1. The article concluded that at temperatures above 200°C, polyurethane decomposes to methyl carbamate in high proportions, while at lower temperatures a catalyst is required.

[0013] WO 2023 / 285545 A1 describes a method for recovering polyurethane, wherein the polyurethane is reacted with a first alcohol, and the low molecular weight carbamate produced therein or during further transesterification with a second alcohol is thermally cracked into the alcohol on which it is based and the isocyanate on which it is based. Particularly preferred first and / or second alcohols are propanol, pentanol, isopropanol, butanol, hexanol, nonanol, octanol, glycerol, ethylene glycol, diethylene glycol, and triethylene glycol. In the examples, the polyurethane flexible foam is reacted once with octanol (at a foam to alcohol mass ratio of 1:2) and once with isopropanol (at a foam to alcohol mass ratio of 1:5).

[0014] EP 3590999 B1 describes a process for the degradation of plastics using methanol or ethanol in the presence of a methoxide catalyst. The examples describe the degradation of flexible polyurethane foams.

[0015] Simón, Borreguero, Lucas and A review article in Waste Management 2018, 76, 147–171 [1] summarizes known polyurethane recycling methods.

[0016] In the literature, efforts to recycle polyurethanes focus on polyurethane foams. However, another important class of polyurethanes is elastomers, which belong to the above-mentioned "CASE" products. Among them, polyester-polyurethane elastomers (also referred to as polyester-urethane elastomers or polyester-urethane rubbers) are an important class of compounds, which are characterized by elasticity similar to that of natural rubber and better chemical and mechanical resistance. The isocyanate component used for particularly high-quality products is naphthalene-1,5-diisocyanate (hereinafter referred to as 1,5-NDI). The corresponding elastomer is Brand name. Solid Made from the chemical reaction of 1,5-NDI, polyester polyols and diols. It is used in the production of wheels and rollers subject to the highest dynamic stresses, as well as industrial parts and semi-finished products. Made from 1,5-NDI, polyester polyol and water. It combines high volume compressibility with minimal lateral stress. Porous Used to produce high-quality, high-performance damping components such as buffers, springs and NVH (noise, vibration, harshness) components. Solid and porous NDI-based polyurethane cast elastomers can also be produced from NDI prepolymers.

[0017] DE 4431961 A1 describes a process for obtaining naphthalene-1,5-diamine (1,5-NDA) by hydrolysis of polyurethanes and / or polyurethane polyureas prepared based on 1,5-NDI (and optionally 1,5-NDA). The hydrolysis is carried out with water at a temperature of 170 to 250°C, optionally at a pressure of 6 to 100 bar, at a pH range of 8.5 to 14, and in the presence of at least an equivalent amount of one or more metal hydroxides and / or metal oxides relative to the urethane groups. This process is characterized by the extremely high purity of the 1,5-NDA obtained. The hydrolysis of low-molecular-weight NDI carbamates obtained in an upstream glycolysis step (via dipropylene glycol) is said to have disadvantages. The hydrolysis process described in DE 4431961 A1 requires the use of large amounts of strong bases, which is not only cost-intensive but also increases the complexity of post-processing and wastewater treatment. Since the chemical decomposition is carried out as direct hydrolysis in the process of DE 4431961 A1, the possibility of obtaining low molecular weight urethanes from the polyurethanes and / or polyurethane polyureas used and of passing them to further processing stages other than chemical hydrolysis is excluded from the outset.

[0018] Therefore, a practical and flexible recycling method for 1,5-NDI-based polyester-polyurethane elastomers is urgently needed. Existing technologies have not yet provided a comprehensive solution.

[0019] Therefore, further improvements are urgently needed in the field of polyurethane recycling. In particular, there is a need to provide methods for the reuse of 1,5-NDI-based polyester-polyurethane elastomers that can recover important raw materials, especially 1,5-NDI (or its precursor, naphthalene-1,5-diamine, 1,5-NDA), and ideally, the monomers and / or chain extenders and crosslinkers of the polyester components.

[0020] Taking this need into account, the subject of the present invention is a process for recovering raw materials (at least one urethane) from a polymer composition containing a polyester-polyurethane elastomer, comprising the following steps:

[0021] (A) providing a polymer composition comprising (at least one)

[0022] a polyester-polyurethane elastomer based on (i) a polyester component, (ii) an isocyanate component and optionally (iii) a chain extender and / or crosslinker having hydroxyl and / or amine functions, in particular an alcohol or amino alcohol having two or more, preferably two to three, hydroxyl groups, in particular having 1 to 10 carbon atoms,

[0023] wherein the polymer composition comprises a first polyester-polyurethane elastomer, the isocyanate component of which comprises naphthalene-1,5-diisocyanate (and preferably, in addition to naphthalene-1,5-diisocyanate, at most further isomers of naphthalene diisocyanate, such as in particular naphthalene-2,6-diisocyanate and naphthalene-1,8-diisocyanate, but no further isocyanates other than naphthalene diisocyanate (NDI), wherein the first polyester-polyurethane elastomer may also be a mixture of different polyester-polyurethane elastomers having an isocyanate component comprising naphthalene-1,5-diisocyanate);

[0024] (B) reacting the polymer composition with a linear primary monohydric alcohol having 1 to 4 carbon atoms (hereinafter also referred to as a chemical decomposition alcohol) (used in a superstoichiometric amount) to obtain a product mixture comprising

[0025] a liquid alcohol phase (comprising (i) unconverted linear primary monoalcohol, (ii) alcoholysis products of urethane and ester bonds, and (iii) optional diols);

[0026] and

[0027] a solid urethane phase (comprising naphthalene-1,5-diisocyanate and a (mono- and / or di-, in particular bis-)urethane of a linear primary monool);

[0028] and

[0029] (C) separating the carbamate from the product mixture.

[0030] Completely surprisingly, it has been found that the conversion of 1,5-NDI units into low-molecular-weight carbamates of linear primary C1-C4 alcohols is simple and easy, which allows for isolation of these in solid form and significantly simplifies the separation of the individual components of the chemical decomposition products from one another. This also allows the recovery of monomer units of the polyester component and / or chain extenders or crosslinkers.

[0031] In the terminology of the present invention, the expression "polymer composition comprising (at least one) polyester-polyurethane elastomer" encompasses all polyester-polyurethane elastomers to be converted in step (B), including at least one 1,5-NDI-based polyester-polyurethane elastomer, referred to herein as the first polyester-polyurethane elastomer. In the simplest case, no other polyester-polyurethane elastomers are present, in which case the polymer composition fed to step (B) (optionally excluding entrained impurities, which may originate, for example, from the original use of the polyester-polyurethane elastomer) is identical to the 1,5-NDI-based polyester-polyurethane elastomer. A plurality of different 1,5-NDI-based polyester-polyurethane elastomers may also be present, differing, for example, in the type of polyester component. In this case, the sum of all 1,5-NDI-based polyester-polyurethane elastomers is considered the first polyester-polyurethane elastomer within the scope of the present invention. As mentioned above, the 1,5-NDI-based polyester-polyurethane elastomer may also contain (smaller proportions of) other NDI isomers; this does not depart from the scope of the present invention. The mass proportion of NDI isomers other than 1,5-NDI, based on the total mass of all naphthalene diisocyanates present, is preferably 0.0% to 2.0%, more preferably 0.0% to 1.0%, even more preferably 0.0% to 0.8%, particularly preferably 0.0% to 0.5%.

[0032] As further explained below, in certain embodiments, additional polyester-polyurethane elastomers based on isocyanates other than 1,5-NDI may be present in the polymer composition. Such additional isocyanates are those having a different carbon-based backbone, e.g., an NDI component that differs only in a slightly different isomer distribution. These additional polyester-polyurethane elastomers are collectively referred to as second polyester-polyurethane elastomers hereinafter. Thus, the second polyester-polyurethane elastomer may also be a mixture of different polyester-polyurethane elastomers having an isocyanate component other than naphthalene-1,5-diisocyanate.

[0033] The polyester component is understood to mean the sum of all polyester constituents which initially form the polyester-polyurethane elastomer by reacting with the isocyanate groups of the isocyanate component, wherein the isocyanate component is understood to mean all isocyanates used for producing the polyester-polyurethane elastomer.

[0034] In the present invention, carbamate refers to an urethane formed during chemical decomposition by reaction with a chemical decomposition alcohol, so that it can be distinguished from the urethane used. For example, the reaction product of the NDI unit of a 1,5-NDI-based polyester-polyurethane elastomer with methanol is called 1,5-NDI-dimethyl carbamate. This choice of terminology is intended solely to simplify the discussion.

[0035] First, various possible embodiments of the present invention are briefly summarized below:

[0036] In a first embodiment of the invention, combinable with all other embodiments except the embodiment necessarily providing for the presence of a second polyester-polyurethane elastomer, the polymer composition comprises no further polyester-polyurethane elastomer than the first polyester-polyurethane elastomer.

[0037] In a second embodiment of the invention, which is combinable with all other embodiments except the embodiment excluding the presence of a second polyester-polyurethane elastomer, the polymer composition comprises a second polyester-polyurethane elastomer, the isocyanate component of which does not comprise naphthalene-1,5-diisocyanate but comprises methylene diphenylene diisocyanate and / or toluene diisocyanate (in particular, i.e. comprises no other isocyanates, wherein the second polyester-polyurethane elastomer can also be a mixture of different polyester-polyurethane elastomers having an isocyanate component different from naphthalene-1,5-diisocyanate (comprising methylene diphenylene diisocyanate and / or toluene diisocyanate)).

[0038] In a third embodiment of the present invention, which is a special configuration of the second embodiment, the mass proportion of the first polyester-polyurethane elastomer, based on the total mass of the first and second polyester-polyurethane elastomers, is 60% to <100%, in particular 60% to 99% or 80% to 98% or 90% to 97% or 95% to 96%.

[0039] In a fourth embodiment of the present invention, which is a special configuration of the second and third embodiments, the polymer composition does not comprise further polyester-polyurethane elastomers than the first and second polyester-polyurethane elastomers.

[0040] In a fifth embodiment of the invention which is a special configuration of the second, third and fourth embodiments, the polyester component of the second polyester-polyurethane elastomer is at least partially based on (i.e., it is polycondensed from) an acid component and an alcohol component, wherein

[0041] The acid component is selected from adipic acid, succinic acid, terephthalic acid, sebacic acid or a mixture of two or more thereof,

[0042] and

[0043] The alcohol component is selected from monoethylene glycol, diethylene glycol or a mixture thereof.

[0044] In a sixth embodiment of the invention, which is a special configuration of the second, third, fourth and fifth embodiments, the polyester component of the second polyester-polyurethane elastomer is at least partially based on a cyclic carboxylic acid ester component (i.e., it is prepared by ring-opening polymerization thereof), wherein the cyclic carboxylic acid component is ε-caprolactone.

[0045] In a seventh embodiment of the present invention, which is a special configuration of the second, third, fourth, fifth and sixth embodiments, the second polyester-polyurethane elastomer comprises urea groups in addition to the urethane groups.

[0046] In an eighth embodiment of the invention, which may be combined with all other embodiments, the polyester component of the first polyester-polyurethane elastomer is at least partially based on (ie, it is polycondensed from) an acid component and an alcohol component, wherein

[0047] The acid component is selected from adipic acid, succinic acid or a mixture thereof,

[0048] and

[0049] The alcohol component of the polyester component of the first polyester-polyurethane elastomer is selected from monoethylene glycol, diethylene glycol, butane-1,4-diol, or a mixture of two or more thereof.

[0050] In a ninth embodiment of the invention, combinable with all other embodiments, the polyester component of the first polyester-polyurethane elastomer is at least partially based on (ie it is prepared by ring-opening polymerization of) a cyclic carboxylic acid ester component, wherein the cyclic carboxylic acid component is ε-caprolactone.

[0051] In a tenth embodiment of the invention, which is combinable with all the other embodiments, the first polyester-polyurethane elastomer comprises urea groups in addition to the urethane groups.

[0052] In an eleventh embodiment of the invention, which can be combined with all other embodiments, the optionally present chain extender and / or crosslinker is selected from butane-1,4-diol, hexane-1,6-diol, hydroquinone bis(2-hydroxyethyl) ether, trimethylolpropane (= 2-ethyl-2-hydroxymethylpropane-1,3-diol), triisopropanolamine, thiodiethylene glycol (= bis(2-hydroxyethyl) sulfide) or a mixture of two or more thereof.

[0053] In a twelfth embodiment of the invention, which can be combined with all other embodiments, the mass proportion of the polyester-polyurethane elastomer in the polymer composition (i.e. the total amount of all polyester-polyurethane elastomers present) is from 60% to 100%, preferably from 80% to 100%, more preferably from 90% to 100%, even more preferably from 95% to 100%, particularly preferably from 97% to 100%, based on the total mass of the polymer composition.

[0054] In a thirteenth embodiment of the invention, which is a special configuration of the twelfth embodiment, the portion of the polymer composition not derived from a polyester-polyurethane elastomer comprises (and optionally consists of) a (particularly thermoplastic) polyurethane based on a polyol component containing polyether polyol and / or polycarbonate polyol (without polyester constituents) and an isocyanate component containing methylene diphenylene diisocyanate and / or toluene diisocyanate.

[0055] In a fourteenth embodiment of the invention, which can be combined with all other embodiments, the linear primary monohydric alcohol is methanol and / or ethanol, in particular methanol.

[0056] In a fifteenth embodiment of the present invention, which can be combined with all other embodiments, in step (B) the mass ratio of 10 to 0.3, preferably 5.0 to 1.0, more preferably 3.5 to 2.5 is used.

[0057] [m(linear primary monoalcohol) / m(polymer composition)]

[0058] A linear primary monohydric alcohol and polymer composition is used.

[0059] In a sixteenth embodiment of the invention, which can be combined with all other embodiments, step (B) is carried out at a pressure of 10 to 120 bar and a temperature of 130°C to 250°C, preferably 20 to 60 bar and 170°C to 220°C, more preferably 25 to 50 bar and 180°C to 210°C.

[0060] In the seventeenth embodiment of the present invention, which is a special configuration of the sixteenth embodiment, step (B) is terminated by decompressing and cooling the product mixture, wherein the unconverted linear primary monohydric alcohol is partially evaporated and, after condensation, recycled again to the reaction of step (B).

[0061] In an eighteenth embodiment of the invention, which is combinable with all other embodiments except those which necessarily provide for the use of a catalyst in step (B), step (B) is carried out without the use of a catalyst.

[0062] In a nineteenth embodiment of the invention, which is combinable with all other embodiments except the embodiment excluding the use of a catalyst in step (B), step (B) is carried out in the presence of a catalyst, wherein the catalyst comprises (i) an alkyl compound, an alkyl halide compound, an acetylacetonate, a carboxylate, an alkoxide and / or a chloride of a metal of Group 1, 4, 11, 12, 13 or 14 of the Periodic Table of the Elements and / or (ii) an amine (especially a tertiary amine).

[0063] In a twentieth embodiment of the invention, which is a special configuration of the nineteenth embodiment, the catalyst is selected from acetates (particularly Zn(OAc)2), transition metal alkoxides (particularly Ti(OBu)4 or bis[[1,1'-(butylimino-kN)bis[2-propanol-kO]](2-)]-,(OC-6-21')-tin, "Desmorapid 13-262Dry"), chlorides (particularly SnCl2), tertiary amines (particularly 4-dimethylaminopyridine, DMAP), acetylacetonates (particularly titanium(IV) acetylacetonate, "TyzorAA105"), and mixtures of two or more of the above catalysts.

[0064] In a twenty-first embodiment of the present invention, which may be combined with all other embodiments, step (C) comprises:

[0065] The solid carbamate phase is separated from the liquid alcohol phase, optionally subsequently washed and, if necessary, subjected to further purification steps in order to isolate the carbamate.

[0066] In a twenty-second embodiment of the present invention, which can be combined with all other embodiments (especially the twenty-first embodiment), the method comprises the following steps:

[0067] (D) further reacting the carbamate isolated in (C), wherein the further reaction comprises one of the following:

[0068] (DI) hydrolyzing the carbamate with water in the presence of a hydrolysis catalyst to form naphthalene-1,5-diamine and a linear primary monoalcohol;

[0069] (D.II) cleavage of carbamates into naphthalene-1,5-diisocyanate and linear primary monools;

[0070] (D.III) hydrogenolyzing the carbamate with hydrogen in the presence of a hydrogenolysis catalyst to form naphthalene-1,5-diamine and a linear primary monohydric alcohol;

[0071] or

[0072] (D.IV) The urethane is reacted with a polyol in the presence or absence of a catalyst to obtain an OH-terminated prepolymer.

[0073] In a twenty-third embodiment of the invention, which is a special configuration of the twenty-second embodiment, the hydrolysis catalyst comprises an (organic or inorganic) Bronsted base selected from the group consisting of: (i) a hydroxide (especially sodium hydroxide, tetramethylammonium hydroxide, potassium hydroxide or tetrabutylammonium hydroxide), (ii) a carbonate (especially an alkali metal carbonate, such as sodium carbonate or potassium carbonate), (iii) a bicarbonate (especially an alkali metal bicarbonate, such as sodium bicarbonate or potassium bicarbonate) or (iv) an orthophosphate or metaphosphate, preferably an orthophosphate (especially an alkali metal phosphate or an alkali metal hydrogenphosphate), or (v) a mixture of two or more of the foregoing Bronsted bases.

[0074] In a twenty-fourth embodiment of the present invention, which is a specific configuration of the twenty-second and twenty-third embodiments, the hydrolysis catalyst comprises an aminoesterase.

[0075] In a twenty-fifth embodiment of the present invention, which is a special configuration of the twenty-fourth embodiment, the aminase used is one of the aminases described in EP 3587570 A1.

[0076] In a twenty-sixth embodiment of the present invention, which is a specific configuration of the twenty-second embodiment, the cleavage of the carbamate in (D.II) is performed without adding a carbamate cleavage catalyst.

[0077] In a twenty-seventh embodiment of the present invention, which is a further specific configuration of the twenty-second embodiment, the cleavage of the carbamate in (D.II) is performed in the presence of a carbamate cleavage catalyst.

[0078] In a twenty-eighth embodiment of the present invention, which is a specific configuration of the twenty-seventh embodiment, the carbamate cleavage catalyst comprises

[0079] Metal-free or metal-containing Bronsted or Lewis acidic catalysts

[0080] or

[0081] Metal-free or metal-containing Brønsted basic or Lewis basic catalysts.

[0082] In a twenty-ninth embodiment of the invention, which is a specific configuration of the twenty-second embodiment, the hydrogenolysis catalyst comprises copper, palladium (particularly Pd / C, PdCl2 or Pd(OAc)2), nickel (particularly Raney nickel), manganese (particularly a Mn complex having a tridentate chelating ligand bound by P and N donor atoms and CO and / or halogen ligands) or platinum (particularly platinum(IV) oxide).

[0083] In a thirtieth embodiment of the invention, which is a special configuration of the twenty-second embodiment, the reaction of the carbamate with the polyol in (D.IV) is carried out in the presence of a catalyst comprising a carbonate, a bicarbonate, a hydroxide, an orthophosphate, a monohydrogen orthophosphate, a metaphosphate, an orthovanadate (all of the above catalysts are preferably used in the form of their sodium or potassium salts), a titanium alkoxide (especially tetra-n-butyl titanate, Ti(OnBu)4), a tertiary amine (especially 1,4-diazabicyclo(2.2.2)octane, "DABCO"), cesium fluoride, a stannate (especially dibutyltin dilaurate, "DBTL", or monobutyltin oxide, n-Bu-Sn(O)OH, "MBTO") or a mixture of two or more of the above catalysts.

[0084] In a thirty-first embodiment of the invention, which can be combined with all embodiments providing for obtaining naphthalene-1,5-diamine, naphthalene-1,5-diamine, optionally after purification, in particular by recrystallization, is reacted (in a manner known per se) with phosgene to give naphthalene-1,5-diisocyanate.

[0085] In a thirty-second embodiment of the present invention, which is a specific configuration of the twenty-first embodiment and all embodiments derived therefrom, the method includes:

[0086] (EIa) extracting the liquid alcoholic phase with an organic and / or aqueous extractant, optionally after distillative separation of the linear primary monoalcohol contained therein, said extractant being selected in particular from the group consisting of: (i) halogenated hydrocarbons, in particular aromatic hydrocarbons, optionally in combination with water, (ii) hydrocarbons, optionally in combination with water, (iii) primary monoalcohols having 6 to 12 carbon atoms, optionally in combination with water, (iv) diols having 2 to 4 carbon atoms, in particular ethylene glycol, propylene glycol, diethylene glycol or 1,4-butanediol, or (v) water; and separating it into a nonpolar phase and a polar phase;

[0087] (EIb) optionally evaporating the optional extractant and / or the optional linear primary monohydric alcohol from the non-polar phase to leave a concentrated organic phase;

[0088] (EIc) reacting the nonpolar phase or (if step (EIb) is carried out) the concentrated organic phase with hydrogen in the presence of a hydrogenolysis catalyst to give an alcohol (the composition of which depends on the nature of the polyester components);

[0089] and optionally

[0090] (EId) The alcohol was further purified by distillation.

[0091] In a thirty-third embodiment of the present invention, which is a specific configuration of the thirty-second embodiment, alcohol is used to synthesize polyester.

[0092] In a thirty-fourth embodiment of the invention, which is a special configuration of the thirty-second and thirty-third embodiments, the polar phase is post-treated to obtain the alcohol component of the polyester component and / or the optional chain extender and / or crosslinker.

[0093] In a thirty-fifth embodiment of the present invention, which is a special configuration of the thirty-fourth embodiment, the alcohol component obtained from the polar phase and / or the chain extender and / or crosslinker obtained from the polar phase are used to produce a new polyester-polyurethane elastomer.

[0094] In a thirty-sixth embodiment of the present invention which is a further specific configuration of the twenty-first embodiment and all embodiments derived therefrom except the thirty-second embodiment, the method comprises

[0095] (E.II.a) reacting the liquid alcohol phase with hydrogen in the presence of a hydrogenolysis catalyst, wherein the linear primary monoalcohol is separated off by distillation before and / or after the reaction with hydrogen, thereby leaving a mixture of alcohols (whose boiling point is higher than that of the linear primary monoalcohol) (the composition of which depends on the nature of the polyester components);

[0096] and

[0097] (E.II.b) The alcohol mixture is separated by distillation into the individual alcohol fractions.

[0098] In a thirty-seventh embodiment of the invention, which is a special configuration of the thirty-sixth embodiment, one or more alcohol fractions from (E.II.b) are used to synthesize polyesters.

[0099] In a thirty-eighth embodiment of the present invention, which is a specific configuration of the thirty-second to thirty-seventh embodiments, the hydrogenolysis catalyst comprises copper, palladium (particularly Pd / C, PdCl2 or Pd(OAc)2), nickel (particularly Raney nickel) or platinum (particularly platinum(IV) oxide).

[0100] In the thirty-ninth embodiment of the present invention, which is a further specific configuration of the twenty-first embodiment and all embodiments derived therefrom except the thirty-second and thirty-sixth embodiments, the liquid alcohol phase obtained in (C) is used for synthesizing polyester.

[0101] In a fortieth embodiment of the invention, which can be combined with all other embodiments, step (A) comprises drying the polyester-polyurethane elastomer-containing polymer composition with air at a temperature of 80° C. to 130° C., wherein the relative air humidity of the air used for drying is preferably at most 80%, more preferably at most 60%, and wherein the drying is carried out in particular for as long as the absolute air humidity of the air after drying is about 2% or more, preferably about 1% or more, higher than the absolute air humidity of the air used for drying, wherein the absolute air humidity before and after drying is in each case measured with the same type of hygrometer (based on the same measuring principle).

[0102] In a forty-first embodiment of the present invention, which can be combined with all other embodiments, the linear primary monoalcohol contains a maximum of 2.0 mass%, preferably a maximum of 1.0 mass%, and more preferably a maximum of 0.50 mass% water, based on the total mass of the linear primary monoalcohol (determined by Karl Fischer titration).

[0103] The embodiments briefly described above and other possible configurations of the present invention are described in more detail below. Unless otherwise clearly apparent to those skilled in the art from the context or otherwise explicitly stated, all of the above embodiments and other configurations of the present invention described below may be combined with each other as needed.

[0104] Providing a polymer composition (step (A))

[0105] In step (A) of the method of the present invention, a polymer composition containing a polyester-polyurethane elastomer to be recycled is provided.

[0106] Step (A) preferably includes preliminary steps for the chemical decomposition in step (B). These steps involve, in particular, mechanical comminution of the polymer composition. Pre-classification is also advantageous to ensure that the polymer composition supplied to the next step (step (B)) is as free as possible from interfering accompanying substances, such as plastics other than the polyester-polyurethane elastomer, metal compounds, or impurities.

[0107] Depending on the properties of the polyester-polyurethane elastomer-containing polymer composition available, it may be advantageous to dry it before the alcoholysis in step (B). For example, air (especially air with a relative humidity of up to 80%, preferably up to 60%) can be treated at elevated temperature (preferably 80° C. to 130° C., for example 120° C.), preferably flowing over the preferably mechanically comminuted polymer composition, until the water content of the polyester-polyurethane elastomer-containing polymer composition is sufficiently low. This can be controlled by measuring the absolute humidity ("water vapor density") of the exhaust air (air exhausted after contact with the polyester-polyurethane elastomer-containing polymer composition). The drying operation can be terminated if the absolute humidity of the exhaust air is at most slightly higher than that of the air used for drying. In particular, the drying operation is continued as long as the absolute humidity of the exhaust air is 2% or more, preferably 1% or more, higher than that of the air used for drying. Thus, if the humidity of the drying air is xg 水 / m 3 空气 , the drying operation is carried out for such a long time, as long as the air humidity of the exhaust gas is (x+[x·0.02])g 水 / m 3 空气 or higher. The air humidity can be measured using a conventional hygrometer. The measurements before and after drying should be made using the same type of hygrometer. Hygrometers that directly provide absolute air humidity are preferred. Alternatively, the absolute air humidity can be calculated from the relative air humidity provided by the hygrometer.

[0108] The polymer composition supplied to step (B) preferably consists of at least 60% polyester-polyurethane elastomer (regardless of whether it is based on 1,5-NDI), based on its total mass. More preferably, the mass proportion of polyester-polyurethane elastomer, based on the total mass of the polymer composition, is 80% to 100%, more preferably 90% to 100%, particularly preferably 95% to 100%, and in particular 97% to 100%, each of these numerical ranges being combinable with any other embodiment, configuration, or variant of the present invention. The portion of the polymer composition not derived from a polyester-polyurethane elastomer that is optionally present preferably comprises (especially thermoplastic) polyurethanes based on a polyol component containing a polyether polyol and / or a polycarbonate polyol (without a polyester component) and an isocyanate component containing methylene diphenyl diisocyanate and / or toluene diisocyanate. The portion of the polymer composition not derived from a polyester-polyurethane elastomer that is optionally present preferably consists of such polyurethanes.

[0109] In principle, this can be any type of polyester-polyurethane elastomer-containing polymer composition, provided that it contains at least one polyester-polyurethane elastomer whose isocyanate component contains or consists of 1,5-NDI. In the present invention, the sum of all 1,5-NDI-based polyester-polyurethane elastomers contained in the polymer composition is referred to as the first polyester-polyurethane elastomer.

[0110] About the first polyester-polyurethane elastomer Polyester component , in one embodiment of the invention, is based on an acid component and an alcohol component (ie is prepared by polycondensation thereof), wherein

[0111] The acid component is selected from adipic acid, succinic acid or a mixture thereof,

[0112] and

[0113] The alcohol component of the polyester component of the first polyester-polyurethane elastomer is selected from monoethylene glycol, diethylene glycol, butane-1,4-diol, or a mixture of two or more thereof.

[0114] It is of course also possible that the polyester component of the first polyester-polyurethane elastomer is based on a cyclic carboxylic acid ester component (ie is prepared by ring-opening polymerization thereof), wherein the cyclic carboxylic acid component is ε-caprolactone.

[0115] A person skilled in the art will appreciate that polyester-polyurethane elastomers (such as the first polyester-polyurethane elastomer described herein) may contain other functional groups in addition to urethane groups, such as, in particular, urea groups, without departing from the scope of the present invention.

[0116] In one embodiment of the present invention, the polymer composition does not comprise further polyester-polyurethane elastomers than the first polyester-polyurethane elastomer.

[0117] However, the polymer composition may also contain at least one other polyester-polyurethane elastomer whose isocyanate component does not contain 1,5-NDI, but rather contains methylene diphenylene diisocyanate (hereinafter referred to as MDI, regardless of isomeric composition) and / or toluene diisocyanate (hereinafter referred to as TDI, regardless of isomeric composition) (in particular, it contains no other isocyanates). In the present invention, the sum of all polyester-polyurethane elastomers not based on 1,5-NDI contained in the polymer composition is referred to as the second polyester-polyurethane elastomer. Therefore, the second polyester-polyurethane elastomer may also be a mixture of different polyester-polyurethane elastomers based on MDI and / or TDI, rather than 1,5-NDI. If the polymer composition containing the first and second polyester-polyurethane elastomers as defined above is to be reused, it is preferably ensured by appropriate pre-classification (see above) that the mass proportion of the first polyester-polyurethane elastomer (based on the total mass of the first and second polyester-polyurethane elastomers) is 60% to <100%, in particular 60% to 99%, 80% to 98%, 90% to 97%, or 95% to 96%. Preferably, the polymer composition comprises no further polyester-polyurethane elastomers than the first and second polyester-polyurethane elastomers (this means that preferably no polyester-polyurethane elastomers which are not based on 1,5-NDI, MDI and / or TDI are present).

[0118] As in the case of the first polyester-polyurethane elastomer, the polyester component of the second polyester-polyurethane elastomer can also be based on an acid component and an alcohol component, or on a cyclic carboxylic acid ester component. In the first case,

[0119] The acid component is preferably selected from adipic acid, succinic acid, terephthalic acid, sebacic acid or a mixture of two or more thereof,

[0120] and

[0121] The alcohol component is preferably selected from monoethylene glycol, diethylene glycol or a mixture thereof.

[0122] In the second case, the cyclic carboxylic acid component is in particular ε-caprolactone.The second polyester-polyurethane elastomer can of course also contain urea groups in addition to urethane groups.

[0123] For all polyester-polyurethane elastomers, the optionally present chain extenders and / or crosslinkers are preferably selected from butane-1,4-diol, hexane-1,6-diol, hydroquinone bis(2-hydroxyethyl) ether, trimethylolpropane (= 2-ethyl-2-hydroxymethylpropane-1,3-diol), triisopropanolamine, thiodiethylene glycol (= bis(2-hydroxyethyl) sulfide) or mixtures of two or more thereof.

[0124] Reacting the polymer composition with a linear primary monohydric alcohol (step (B))

[0125] In step (B) of the process according to the invention, the polymer composition provided in step (A) is reacted with a linear primary monohydric alcohol (used in a superstoichiometric amount), i.e., a chemical decomposition alcohol (chemical decomposition of the polymer backbone). For this purpose, methanol and / or ethanol are preferably used, more preferably methanol.

[0126] It is preferred that the mass ratio

[0127] [m(linear primary monoalcohol) / m(polymer composition)]

[0128] The linear primary monoalcohol used should contain as little water as possible, preferably 5.0 to 1.0, and more preferably 3.5 to 2.5. It is obvious that the linear primary monoalcohol used should contain as little water as possible to enable the most selective formation of urethanes. It is particularly preferred that the linear primary monoalcohol used contain a maximum of 2.0 mass %, preferably a maximum of 1.0 mass %, and more preferably a maximum of 0.50 mass % of water, based on its total mass. This can be achieved, if necessary, by drying measures known per se. In the present invention, the mass of the linear primary monoalcohol refers in each case to the total mass including any water present. If necessary, the water content of the linear primary monoalcohol can be determined by Karl Fischer titration; this is the key method in the present invention. The Karl Fischer titration method has been described many times and is well known to those skilled in the art. All possible configurations of the basic principle of the Karl Fischer titration method generally provide results with sufficiently good consistency within the scope of the present invention. In case of doubt, the Karl Fischer titration method described in DIN 51777 Part 1 (March 1983) is essential for the present invention.

[0129] The reaction in step (B) is preferably carried out at a pressure of 10 to 120 bar and a temperature of 130 to 250° C., more preferably at a pressure of 20 to 60 bar and a temperature of 170 to 220° C., most preferably at a pressure of 25 to 50 bar and a temperature of 180 to 210° C. Unless expressly stated otherwise, the pressure values ​​here and hereinafter are to be regarded as absolute pressures.

[0130] The chemical decomposition is preferably terminated by decompressing the product mixture under pressure (especially to ambient pressure) and cooling it (especially to ambient temperature), with some unconverted linear primary monohydric alcohol being evaporated and, after condensation, being recycled back into the reaction in step (B). Of course, cooling can also be performed first and then decompressing; the phrase "decompressing and cooling" does not necessarily imply a sequence. If cooling is performed before decompressing, the proportion of evaporated chemical decomposition alcohol will be correspondingly smaller. The duration of the reaction in step (B) from the time the desired reaction temperature is reached to the time a temperature below the standard boiling point (=boiling point at standard pressure, i.e., 1013.25 hPa) of the chemical decomposition alcohol used is preferably 1.0 to 10 hours, more preferably 3.0 to 8.0 hours, and most preferably 4.0 to 6.0 hours.

[0131] The chemical decomposition in step (B) can be carried out in the presence or absence of a catalyst. If a catalyst is used, it is preferably selected from (i) alkyl compounds, alkyl halide compounds, acetylacetonates, carboxylates, alkoxides and / or chlorides of metals from Groups 1, 4, 11, 12, 13 or 14 of the Periodic Table of the Elements and / or (ii) amines, especially tertiary amines. In a particularly preferred embodiment, the catalyst used is an acetate (especially Zn(OAc)2), a transition metal alkoxide (especially Ti(OBu)4 or bis[[1,1'-(butylimino-kN)bis[2-propanol-kO]](2-)]-,(OC-6-21')-tin, "Desmorapid 13-262Dry"), a chloride (especially SnCl2), a tertiary amine (especially 4-dimethylaminopyridine, DMAP), an acetylacetonate (especially titanium(IV) acetylacetonate, "TyzorAA 105"), or a mixture of two or more of these catalysts.

[0132] Suitable reactors for step (B) are in principle all reactors known in the art for this purpose (chemical decomposition). Particularly suitable are stirred tanks (stirred reactors; batch, continuous or semi-continuous operation) and tubular reactors (continuous flow reaction tubes, wherein a plurality of reactors can also be combined to form so-called shell and tube reactors).

[0133] The product mixture produced by chemical decomposition includes

[0134] a liquid alcoholic phase (comprising (i) unconverted linear primary monoalcohol, (ii) alcoholysis products of urethane and ester bonds, and (iii) optional chain extenders and / or crosslinkers);

[0135] and

[0136] Solid urethane phase (comprising (mono- and / or di-, in particular bis-)urethanes of naphthalene-1,5-diisocyanate and of linear primary monools).

[0137] It is possible, and does not depart from the scope of the present invention, for the product mixture to contain other components in addition to the aforementioned components, such as small amounts of naphthalene-1,5-diamine (hereinafter referred to as 1,5-NDA), particularly in the solid phase. Due to solubility equilibrium, the aforementioned components may not be 100% present in either the liquid or solid phase; for example, small amounts of the optional chain extender and / or crosslinker may enter (become "encapsulated" in) the solid urethane phase. This situation, of course, does not depart from the scope of the present invention. If the initial polymer composition also includes a second polyester-polyurethane elastomer, MDI urethane and / or TDI urethane are also produced. These components enter primarily or entirely into the liquid alcohol phase. If a small portion enters the solid urethane phase, these components (or, depending on the further reaction of the urethane, their conversion products) can be separated by conventional purification methods.

[0138] Separation of carbamate from product mixture (step (C))

[0139] In step (C) of the process according to the invention, the carbamate is separated from the product mixture so that it can be sent for further use.

[0140] In the simplest case, step (C) merely involves separating the solid carbamate phase from the liquid alcohol phase by solid-liquid phase separation (especially by filtration or centrifugation). This can then be washed and, if necessary, followed by further purification steps. For example, the solid carbamate phase can be recrystallized in an organic solvent inert to carbamates to separate out the optionally present MDI carbamate and / or TDI carbamate fractions (or other entrained accompanying substances). Recrystallization is particularly advantageous when the polymer composition provided in step (A) contains other components that are not derived from the polyester-polyurethane elastomer. For example, if a thermoplastic polyurethane fraction based on polyether polyols is present, such polyether polyols can also at least partially enter the carbamate phase. After separation in the recrystallization, these substances can be reused or, if physical utilization is not desirable in terms of quantity, burned, preferably to utilize the energy of the combustion heat.

[0141] Further reaction of carbamate (step (D))

[0142] The carbamate obtained in this way is preferably reacted further in step (D). Suitable further reactions here include in particular:

[0143] (DI) hydrolyzing the carbamate with water in the presence of a hydrolysis catalyst to form naphthalene-1,5-diamine and a linear primary monoalcohol;

[0144] (D.II) cleavage of carbamates into naphthalene-1,5-diisocyanate and linear primary monools;

[0145] (D.III) hydrogenolyzing the carbamate with hydrogen in the presence of a hydrogenolysis catalyst to form naphthalene-1,5-diamine and a linear primary monohydric alcohol;

[0146] or

[0147] (D.IV) The urethane is reacted with a polyol in the presence or absence of a catalyst to obtain an OH-terminated prepolymer.

[0148] The hydrolysis, cleavage and hydrogenolysis of carbamates and their reaction with polyols (transurethrone) are reactions known in principle to the expert community and are therefore only briefly described here.

[0149] The hydrolysis of (DI) yields the amine corresponding to the isocyanate of the isocyanate component, namely naphthalene-1,5-diamine. If other carbamate moieties are present during the hydrolysis process, particularly MDI carbamate and / or TDI carbamate moieties, these will naturally also hydrolyze to the corresponding amines. Since naphthalene-1,5-diamine has a relatively low water solubility compared to other amines, such as the isomers of toluenediamine (TDA), 1,5-NDA can be isolated as a solid after hydrolysis. If the purity of the isolated solid material is insufficient, it can be improved, for example, by recrystallization in an organic solvent (such as monochlorobenzene). Recrystallization can also be used to separate previously entrained solid impurities from the polymer composition. Here, the solid amine phase is dissolved in an organic solvent at high temperature (e.g., 120°C) and pressure up to 4 bar (absolute) and separated from undissolved solids by filtration and / or centrifugation. Subsequently, the 1,5-NDA is crystallized by annealing reduction and separated from the organic solvent by filtration / centrifugation. The organic solvent can preferably be purified by distillation, allowing a large portion of the product to be recycled. Furthermore, a substream of the organic solvent can also be used to wash the solid amine phase after carbamate hydrolysis.

[0150] In principle, such a hydrolysis can be carried out analogously to the direct hydrolysis of polyurethanes (see the literature cited above, in particular the review article [1]). The amines thus obtained (1,5-NDA and optionally other amines, such as in particular MDA and / or TDA) can be used for all purposes known in the art for such amines, in particular they can be reused for phosgenation to the corresponding isocyanates. The isocyanates thus obtained can be reused in the production of polyurethanes, in particular in the production of polyester-polyurethane elastomers. The hydrolysis process can be assisted by a hydrolysis catalyst. The following catalysts are particularly suitable for this purpose:

[0151] (I) an (organic or inorganic) Bronsted base selected from (i) a hydroxide (especially sodium hydroxide, tetramethylammonium hydroxide, potassium hydroxide or tetrabutylammonium hydroxide), (ii) a carbonate (especially an alkali metal carbonate, such as sodium carbonate or potassium carbonate), (iii) a hydrogen carbonate (especially an alkali metal hydrogen carbonate, such as sodium hydrogen carbonate or potassium hydrogen carbonate), (iv) an orthophosphate or a metaphosphate, preferably an orthophosphate (especially an alkali metal phosphate or an alkali metal hydrogen phosphate), or (v) a mixture of two or more of the aforementioned Bronsted bases

[0152] and / or

[0153] (II) an aminase, in particular one of the aminases described in EP 3587570 A1.

[0154] However, it is also conceivable to obtain the isocyanate of the isocyanate component directly from the carbamate by cleaving the carbamate into the isocyanate of the isocyanate component and the chemical decomposition alcohol (carbamate cleavage according to (D.II)) by purely thermal means or in the presence of a carbamate cleavage catalyst. In the catalytic embodiment, suitable carbamate cleavage catalysts are in particular:

[0155] (I) Metal-free or metal-containing Bronsted or Lewis acidic catalysts

[0156] or

[0157] (II) Metal-free or metal-containing Brønsted basic or Lewis basic catalysts.

[0158] For more detailed information, please refer to W. Leitner et al., Carbon 2 Polymer-Chemical Utilization of CO 2 in the Production of Isocyanates, Chapter 4, “Carbamate Cleavage”, published in Chem. Ing. Tech. 2018, 90, 1504-1512, and the literature cited therein.

[0159] The workup variant according to (D.II) directly provides the isocyanate of the isocyanate component, thus eliminating the need for further phosgenation. The isocyanate of the isocyanate component is at least 1,5-NDI. If other carbamates (especially MDI carbamate and / or TDI carbamate) also partially enter the solid carbamate phase and have not been separated beforehand, they are also converted into the corresponding isocyanates. Separation of the various isocyanates can optionally be easily accomplished using known techniques (recrystallization, distillation).

[0160] The amine corresponding to the isocyanate of the isocyanate component, i.e. at least 1,5-NDA as described in (DI), can also be obtained by hydrogenolysis of carbamates with hydrogen according to (D.III). A method starting directly from polyurethanes and which can also be used in this step (D.II) is described in Hydrogenative Depolymerization of Polyurethanes Catalyzed by Manganese Pincer Complex by Viktoriia Zubar et al., published in ChemSusChem 2022, 15, e202101606 [2]. Reference is also made to the literature cited in [2]. Possible uses of amines are the same as outlined in (DI). Preferably, a catalyst is used to assist the hydrogenolysis. Suitable hydrogenolysis catalysts are, in particular, catalysts comprising

[0161] Palladium (especially Pd / C, PdCl2 or Pd(OAc)2), copper, nickel (especially Raney nickel), manganese (especially Mn complexes with tridentate chelating ligands bound via P and N donor atoms and CO and / or halogen ligands) or platinum (especially platinum(IV) oxide).

[0162] The workup variants according to (DI) and (D.III) thus give the amine corresponding to the isocyanate of the isocyanate component (here at least 1,5-NDA), which in turn can, optionally after purification (especially by recrystallization), be used for all applications known in the art. In particular, the amine can be reacted with phosgene in a manner known per se to form the corresponding isocyanate (here at least 1,5-NDI) and used to produce novel polyurethanes, especially novel polyester-polyurethane elastomers.

[0163] Another possibility for further processing of the carbamates is the reaction of the carbamates in step (C) with polyols to form OH-terminated prepolymers according to (D.IV). Chemically, this is a transurethanization and is therefore, in principle, of the same type of reaction as the diolization of polyurethanes (for this, see the literature cited above, especially the review article [1]). For this purpose, the carbamates are reacted with polyols, the OH groups of the polyols being used stoichiometrically or superstoichiometrically, in particular slightly superstoichiometrically (e.g., a molar excess of 5% to 10%), relative to the carbamate functional groups present. This reaction forms OH-terminated prepolymers. These prepolymers can be used for all purposes known in the art; in particular, they can be reacted with isocyanates and used as prepolymers for elastomers, flexible and rigid foam applications, thermoplastic polyurethanes, coatings, and adhesives.

[0164] The boiling point of the polyol used in step (D.IV) is higher than the boiling point of the chemical decomposition alcohol used. In a particularly preferred embodiment, the chemical decomposition alcohol is continuously removed from the reaction mixture by distillation during the reaction with the polyol. The reaction can optionally be carried out in the presence of a catalyst. The latter preferably includes carbonates, bicarbonates, hydroxides, orthophosphates, monohydrogen orthophosphates, metaphosphates, orthovanadates (wherein all of the above catalysts are preferably used in the form of their sodium or potassium salts), titanium alkoxides (especially tetra-n-butyl titanate, Ti(O-nBu)4), tertiary amines (especially 1,4-diazabicyclo(2.2.2)octane, "DABCO"), cesium fluoride, stannates (especially dibutyltin dilaurate, "DBTL", or monobutyltin oxide, n-Bu-Sn(O)OH, "MBTO") or mixtures of two or more of the above catalysts.

[0165] Typical suitable polyols are diols (especially ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-butenediol, 1,4-butynediol, neopentyl glycol, 1,5-pentanediol, methylpentanediol (e.g. 3-methyl-1,5-pentanediol), 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, bis(hydroxymethyl)cyclohexane (e.g. 1,4-bis(hydroxymethyl)cyclohexane), triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, The polyols used in step (D.IV) may also include diols, tripropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, and polyester polyols, such as polyester polyols formed from ethylene glycol and adipic acid, triols (especially trimethylolpropane, glycerol, trishydroxyethyl isocyanurate), tetraols (especially pentaerythritol), and polyols obtainable from renewable raw materials (especially sorbitol, hexitols, sucrose, starch, starch hydrolysates, cellulose, cellulose hydrolysates, and hydroxy-functionalized fats and oils, especially castor oil), as well as all modification products of these polyols with varying amounts of ε-caprolactone. The polyols used in step (D.IV) may also be polyether polyols, in particular polyether polyols having a number-average molar mass Mn, determined according to DIN 55672-1 (2016-03), in the range of 18 g / mol to 8000 g / mol and a functionality (calculated based on the H-functional starter used to prepare the polyether polyol) of 2 to 3. The polyether polyols preferably are formed from repeating ethylene oxide and propylene oxide units, wherein the proportion of propylene oxide units is preferably 35% to 100%, and more preferably the proportion of propylene oxide units is 50% to 100%. They may be random copolymers, gradient copolymers, alternating copolymers or block copolymers of ethylene oxide and propylene oxide.

[0166] In all four variants, the chemical decomposition alcohol used is released again and can be recovered by distillation and used again in the chemical decomposition.

[0167] Further treatment of the liquid alcohol phase (step (E))

[0168] The liquid alcohol phase obtained after separation of the solid urethane phase in step (C) is preferably further processed in step (E). This liquid alcohol phase contains at least unconverted chemical decomposition alcohol and degradation products of the polyester on which the polyester-polyurethane elastomer formed in step (B) is based. Depending on the starting components used in the polyester production, these are (i) esters of acid components with chemical decomposition alcohols (e.g., methyl adipate, hereinafter referred to as ADM) and alcohol components (e.g., monoethylene glycol), or (ii) open-chain esters of cyclic carboxylic acid components (e.g., methyl 6-hydroxyhexanoate). If chain extenders and / or crosslinkers are also used in the production of the polyester-polyurethane elastomer, these are released again in step (B) and likewise enter the liquid alcohol phase.

[0169] For polymer compositions that contain, in addition to a 1,5-NDI-based polyester-polyurethane elastomer ("first polyester-polyurethane elastomer"), further polyester-polyurethane elastomers ("second polyester-polyurethane elastomer"), in particular polyester-polyurethane elastomers based on MDI and / or TDI, their degradation products, i.e., "non-NDI urethanes," in particular MDI urethanes and / or TDI urethanes, primarily enter the liquid alcohol phase and are further processed together with the 1,5-NDI urethanes due to their superior solubility compared to the 1,5-NDI urethanes. The same applies to the slightly soluble portion of the 1,5-NDI urethanes.

[0170] In a first variant, step (E) comprises the following sequence of steps:

[0171] (EIa) extracting the liquid alcoholic phase with an organic and / or aqueous extractant, optionally after distillative separation of the linear primary monoalcohol contained therein, said extractant being selected in particular from the group consisting of: (i) halogenated hydrocarbons, in particular aromatic hydrocarbons, optionally in combination with water, (ii) hydrocarbons, optionally in combination with water, (iii) primary monoalcohols having 6 to 12 carbon atoms, optionally in combination with water, (iv) diols having 2 to 4 carbon atoms, in particular ethylene glycol, propylene glycol, diethylene glycol or 1,4-butanediol, or (v) water; and separating it into a nonpolar phase and a polar phase;

[0172] (EIb) optionally evaporating the optional extractant and / or the optional linear primary monohydric alcohol from the non-polar phase to leave a concentrated organic phase;

[0173] (EIc) reacting the nonpolar phase or (if step (EIb) is carried out) the concentrated organic phase with hydrogen in the presence of a hydrogenolysis catalyst to give an alcohol (the composition of which depends on the nature of the polyester components);

[0174] and optionally

[0175] (EId) The alcohol was further purified by distillation.

[0176] Step (EIa) The purpose of the extraction in step (C) is to obtain a nonpolar phase and a polar phase that are separable from each other and thereby allow for a (preliminary) separation of the components of the alcoholic phase. For example, ADM primarily enters the nonpolar phase. This can be achieved by using a relatively nonpolar extractant in which ADM is soluble, or by using a relatively polar extractant that "dissolves out" the more polar components of the alcoholic phase, leaving behind an ADM-rich nonpolar phase. Therefore, the nonpolar phase typically contains esters of the acid components, which are optionally dissolved in the nonpolar component of the extractant. If the alcoholic phase in step (C) also contains carbamates (1,5-NDI carbamate and other carbamates, particularly MDI carbamate and / or TDI carbamate), these are typically also dissolved in the nonpolar phase. The polar phase typically contains the alcohol components of the polyester and the chain extender / crosslinker dissolved in the chemically decomposed alcohol (if not previously evaporated), as well as the optional polar component of the extractant.

[0177] The compounds dissolved in the non-polar phase, in particular the esters of the acid component, are hydrogenolyzed in step (EIc), optionally after evaporation of the volatile components in step (EIb). The catalysts suitable for hydrogenolysis are the same as those described in step (D.III) above. The esters of the acid component are converted into alcohols by hydrogenolysis (this alcohol is of course mixed with the chemical decomposition alcohol released from the cleavage of the ester bond during the hydrogenolysis process). Therefore, if the polyester of the polyester-polyurethane elastomer is based on the acid component adipic acid and the chemical decomposition alcohol used in step (B) is methanol, methyl adipate will be formed, which enters the hydrogenolysis according to step (EIc) via the alcohol phase and is cracked there into 1,6-hexanediol and methanol. The optional methyl 6-hydroxycaproate portion (from the partially present ε-caprolactone-based polyester component) is converted into 1,6-hexanediol in this step.

[0178] Preferably, distillation is then performed to purify the alcohol (Step (EId). The extractant which is optionally still present at this point is removed by distillation, just like the chemical decomposition alcohol (which is released during the hydrogenolysis process or optionally entrained into the hydrogenolysis process). The carbamates dissolved in the liquid alcohol phase from step (C) are converted into the corresponding amines during the hydrogenolysis process and remain in the bottom product of the distillation. Whether the physical utilization of these amines is feasible depends on the boundary conditions, in particular their yield. If the polymer composition provided in step (A) contains a large proportion of the second polyester-polyurethane elastomer and relatively large amounts of MDI carbamate and / or TDI carbamate enter the hydrogenolysis of step (EIc), it may be advantageous to further process the resulting amines, in particular to separate them from the optionally also present 1,5-NDA fraction and to further purify them. The amines obtained in this way can be used as described above in step (DI). However, it is also conceivable that the amines are produced only in such quantities that physical reuse is not possible. In this case, it is preferred to burn the amines and utilize the energy of the released heat of combustion.

[0179] The alcohol obtained in the hydrogenolysis process can be used for all purposes known in the technical field for such alcohols; in particular, it can be used for the synthesis of novel polyesters.

[0180] The polar phase is also preferably post-processed to recover the alcohol component of the polyester component and / or any chain extender / crosslinker present therein. To this end, the components of the polar phase can first be separated by distillation. The alcohol component and / or the chain extender or crosslinker thus obtained can be used for all purposes known in the art for such compounds; in particular, they can be used for the synthesis of novel polyester-polyurethane elastomers.

[0181] In a second variant, step (E) comprises the following steps:

[0182] (E.II.a) reacting the liquid alcohol phase with hydrogen in the presence of a hydrogenolysis catalyst, wherein the linear primary monohydric alcohol is separated off by distillation before and / or after the reaction with hydrogen, thereby leaving a mixture of alcohols (having a higher boiling point than the linear primary monohydric alcohol) (the composition of which depends on the nature of the polyester components);

[0183] and

[0184] (E.II.b) The alcohol mixture is separated by distillation into the individual alcohol fractions.

[0185] In this variant, the liquid alcohol phase is subjected to hydrogenolysis ( Step (E.II.a) ), without extractive pre-isolation. Suitable catalysts are again the same as those described in step (D.III).

[0186] The chemical decomposition alcohol can be separated off (and optionally the water present) before or after the hydrogenolysis. In this process, the hydrogenolysis product comprises, in addition to the alcohol formed by the hydrogenolytic cleavage (e.g. hexane-1,6-diol) and the chemical decomposition alcohol (at least part of which is released in the hydrogenolysis), an alcohol component (e.g. monoethylene glycol) and optionally a chain extender or crosslinker, and optionally an amine (formed from the carbamate dissolved in the liquid alcohol phase). By distillation ( Step (E.II.b) ), separate alcohol fractions are obtained from a mixture comprising at least one alcohol. These fractions can be used for all purposes known in the art for such alcohols, in particular for the synthesis of polyesters. The amines which are optionally present can be further processed as described for the first variant.

[0187] If the polymer composition sent to step (B) contains polyurethane parts that are not derived from polyester-polyurethane elastomers (especially thermoplastic), their degradation products can also enter the liquid alcohol phase. In this case, extraction is preferably carried out (first variant). For example, polyether polyols can enter the liquid alcohol phase. During the extraction process, polyether polyols usually enter the non-polar phase. In this case, an optional distillation should be carried out according to (EId), wherein the polyether polyols are now obtained as a high-boiling fraction. The polyether polyols thus obtained can be physically reused or burned, preferably using the energy of the released heat of combustion. If the extraction is omitted, the polyether polyols are similarly obtained in step (E.II.b).

[0188] If the polymer composition contains polycarbonate components, these components are cleaved in step (B), in particular into bisphenol A and chemically decomposed alcohol carbonates. Both products preferably pass into a liquid alcohol phase. In this case, the liquid alcohol phase is also preferably post-treated according to the first variant; step (EId) is also preferably carried out. Bisphenol A or its resulting conversion products are separated in a distillation (EId) after hydrogenolysis. The chemically decomposed alcohol carbonates are preferably transferred to a polar phase during the extraction process and, as long as they do not decompose into the alcohol and CO2 on which they are based, can be separated therefrom by distillation and further utilized, for example, for the production of new polycarbonates.

[0189] In a third variant of step (E), finally,

[0190] (E.III) The liquid alcohol phase obtained in (C) is used (directly) for the synthesis of polyesters.

[0191] Polyesters can be prepared by known methods. Other acid or alcohol components, as well as esters of carboxylic acids with low molecular weight alcohols and catalysts can be added to the resulting liquid alcohol phase to influence the physical properties of the polyester and the esterification reaction itself. Optionally, carboxyl-functional compounds and their derivatives, such as adipic acid, succinic acid, terephthalic acid, or sebacic acid, and compounds selected from glycols, such as monoethylene glycol, diethylene glycol, and butanediol, can also be added.

[0192] Suitable catalysts generally include all known catalysts for producing polyesters. These include tin salts such as tin dichloride or tin diethylhexanoate; titanates such as tetrabutyl titanate or Tyzor EZ; or strong acids such as p-toluenesulfonic acid; and organotin compounds such as dibutyltin dilaurate or bismuth salts; as well as carboxylates of zinc, manganese, and other transition metals. Alternatively, polyester polyols can be produced without the use of a catalyst. The catalyst can be added at the beginning of the reaction or during the reaction, and can optionally be specifically deactivated during the reaction. The esterification reaction can be carried out in a known manner, such that at least the reactants are pre-loaded and reacted by heating. Polyester polyols are typically produced without the use of additional solvents. The removal of the reaction water and the released chemical decomposition alcohols is preferably assisted by applying negative pressure, especially near the end of the esterification reaction. The removal of the reaction water and chemical decomposition alcohols can also be assisted by purging with an inert gas such as nitrogen or argon. The pressure used here is 1 to 500 mbar. However, the esterification can also be carried out at temperatures above 500 mbar. However, the esterification can also be carried out with the addition of other solvents, in particular solvents entrained with water (azeotropic esterification), such as benzene, toluene or dioxane. Solvents can also be added in order to remove the chemical decomposition alcohol contained in the low molecular weight ester from the reaction mixture by azeotropy.

[0193] The esterification or transesterification reaction is preferably carried out under a reduced pressure of 1 mbar to 600 mbar, in particular under a pressure of less than 500 mbar. The reaction can be carried out in a single-stage or multi-stage esterification or transesterification reaction of the acid component and the alcohol component. Example:

[0194] The pressure data given in the examples are given relative to atmospheric pressure ("overpressure").

[0195] Example 1 (Present invention; chemical decomposition using methanol without adding a chemical decomposition catalyst; steps (A) to (C))

[0196] Approximately 500 g of a polyester-polyurethane elastomer (PEPUE) based on a polyester component (A)(i) formed from adipic acid, 1,4-butanediol, and monoethylene glycol, an isocyanate component (A)(ii) formed from NDI (wherein the isocyanate component constitutes 20% of the total mass of the PEPUE), and a chain extender (A)(iii) of 1,4-butanediol were added to a stirred autoclave with an internal volume of 3 liters (step (A)). Approximately 1000 g of methanol were added, and the reactor was rendered inert by purging with nitrogen. Subsequently, the pressure in the reactor was adjusted to approximately 60 bar by adding nitrogen. The stirrer speed was adjusted to 400 rpm, and the reactor contents were heated at a heating rate of 1°C / minute to an internal temperature of 200°C. Upon reaching this temperature, a pressure of approximately 125 bar was measured. The reactor was then stirred at the same internal temperature for 6 hours. The reactor contents were then cooled to 25°C, the excess pressure in the reactor was released, and the autoclave contents were transferred to a glass bottle at room temperature (step (B)). Subsequently, the solid was filtered off, washed with methanol and dried (step (C)).

[0197] The experiment was repeated twice and the solid products obtained were combined. A total of 549 g of solid material was obtained, which consisted of 42% (by 1 HNMR determination) 1,5-NDI-carbamic acid dimethyl ester is formed, corresponding to a yield of 59% of the theoretical value.

[0198] Example 2 (Present invention; chemical decomposition using ethanol without adding a chemical decomposition catalyst; steps (A) to (C))

[0199] 72.3 g of the same PEPUE as in Example 1 was reacted with 197.6 g of ethanol in a similar manner to obtain 30.4 g of a sticky solid. 1 HNMR determination) contains 20.3 g of 1,5-NDI-dimethylcarbamate.

[0200] Example 3 (Present invention, alkaline hydrolysis of NDI-dimethyl carbamate; step (DI))

[0201] 255.1 g of the solid material from Example 1, along with 94.5 g of sodium hydroxide pellets and 2070 g of water (demineralized water, "VE"), were placed in a pressure-resistant stirred autoclave (internal volume 3 liters). The reactor was inertized with nitrogen and the pressure was adjusted to 5 bar before heating. The reactor contents were then heated to the desired reaction temperature of 220°C at a rate of approximately 1°C / minute. After exceeding 100°C, the stirrer was started at 400 rpm. After reaching 220°C, the reaction temperature was maintained for one hour. The maximum pressure at this point was approximately 28 bar. The reactor contents were then cooled to room temperature over 2 hours and then depressurized to ambient pressure. After opening the reactor, the entire reaction mixture was blanketed with nitrogen and transferred to a glass bottle using a pump. The resulting brown solid was then filtered through a glass frit, washed with water until the pH was neutral, and dried overnight in a vacuum drying oven at 50°C and 100 mbar. 59 g of solid were isolated. Analysis of the solid by gas chromatography showed that it consisted of 99.5% 1,5-NDA, corresponding to a yield of about 96% of theory (based on the dimethyl 1,5-NDI-carbamate contained in the solid used for hydrolysis in Example 1).

[0202] Example 4 (Extraction of dimethyl adipate (ADM); Step (E.1.a))

[0203] Methanol was removed from a portion of the liquid alcohol phase remaining after solid separation in Example 1 by distillation. This left a mixture with a high proportion of dimethyl adipate (67% by mass) as well as monoethylene glycol and 1,4-butanediol. This biphasic mixture at room temperature was extracted once with various extractants in a 1:1 mass ratio (Examples 4a to 4c). In two experiments (Examples 4d and 4e), an extractant consisting of an organic solvent and water was used; in these cases, the mixture, organic solvent, and water were used in a 1:1:1 ratio. The extraction was carried out at 20°C. To evaluate the experiments, the distribution coefficient K (the ratio of the mass proportion of ADM in the ADM-rich phase to the mass proportion of ADM in the ADM-depleted phase) was determined. The distribution of monoethylene glycol (MEG) and 1,4-butanediol (BDO) was also determined.

[0204] Table 1: Partition coefficients of ADM, MEG, and BDO

[0205]

[0206] Note: w = mass ratio; V = comparative example.

[0207] ADM was successfully extracted from the methanol-free liquid alcohol phase using monochlorobenzene (Example 4a), with MEG and BDO remaining essentially as the main components of the polar phase. The use of non-polar extractants such as hexane resulted in less favorable results (see Example 4b; K ADMLower than Example 4a), but still usable. The results of using water in combination with a less polar organic solvent (monochlorobenzene) or a non-polar organic solvent (hexane) (Examples 4d and 4e) are improved over the use of these solvents alone (Examples 4a and 4b).

[0208] Water alone was also suitable as the extractant (Example 4c), wherein in this case, MEG and BDO were extracted from the methanol-depleted liquid alcohol phase instead of ADM. Compared to the other examples, the proportion of MEG and BDO in the ADM phase was slightly increased.

[0209] With a suitable process concept (eg by multi-stage extraction), all these values ​​can also be optimized.

[0210] Example 5 (the present invention, without adding a chemical decomposition catalyst, using methanol for chemical decomposition, and then The dimethyl adipate formed is subjected to hydrogenolysis; steps (A) to (C) and (E.II.a))

[0211] Approximately 167 g of a polyester-polyurethane elastomer (PEPUE) based on a polyester component (A)(i) formed from adipic acid, 1,4-butanediol, and monoethylene glycol, an isocyanate component (A)(ii) formed from NDI (wherein the isocyanate component constitutes 20% of the total mass of the PEPUE), and a chain extender (A)(iii) of 1,4-butanediol were added to a stirred autoclave with an internal volume of 1 liter (step (A)). Approximately 333 g of methanol were added, and the reactor was inertized by purging with nitrogen. The reaction mixture was heated to a reaction temperature of 200°C while stirring (500 rpm), during which the pressure rose to 40 bar. After a reaction time of 180 minutes at 200°C, the reactor was cooled and, after reaching an internal temperature of approximately 25°C, the pressure was reduced. The product was then discharged (step (B)). The resulting solid was isolated by filtration, washed with MeOH, and then dried under vacuum (step (C)).

[0212] A portion of the liquid alcohol phase remaining after separation of the solid was hydrogenated in the presence of a heterogeneous copper oxide catalyst (Ranido RCAT-2200, 20% by mass based on the amount of dimethyl adipate) (step (E.II.a) The composition of the liquid phase was as follows: 70.9% by mass of MeOH, 6.2% by mass of monoethylene glycol, 2.3% by mass of 1,4-butanediol, 18.6% by mass of dimethyl adipate, and a total of 2.0% by mass of mono- and bis-NDI-methyl carbamate.

[0213] 2.00 ml of the alcohol liquid phase and 20 mg of n-tetradecane (GC standard) were pre-loaded in a 20 ml autoclave. After the reactor was inertized with hydrogen, the pressure was adjusted to 70 bar with hydrogen, and the reaction mixture was stirred at a temperature of 220 ° C for 16 hours (900 rpm) in an aluminum heating block. Subsequently, the reactor was cooled in an ice bath and ventilated. The reaction mixture was diluted with 1,4-dioxane (2 ml) and filtered. After filtration, a sample of the reaction mixture was taken and analyzed by gas chromatography. The yield of 1-methyl hexanoate-6-ol was measured to be 45.4%, and the yield of hexane-1,6-diol was 51.9%.

Claims

1. A method for recovering raw materials from a polymer composition containing a polyester-polyurethane elastomer, comprising the following steps: (A) providing a polymer composition comprising a polyester-polyurethane elastomer based on (i) a polyester component, (ii) an isocyanate component and optionally (iii) a chain extender and / or a crosslinker having hydroxyl and / or amine functional groups, wherein the polymer composition comprises a first polyester-polyurethane elastomer, the isocyanate component of which comprises naphthalene-1,5-diisocyanate; (B) reacting the polymer composition with a linear primary monohydric alcohol having 1 to 4 carbon atoms to obtain a product mixture comprising liquid alcohol phase; and solid urethane phase; and (C) separating the carbamate from the product mixture.

2. The method of claim 1, wherein the polymer composition does not contain other polyester-polyurethane elastomers other than the first polyester-polyurethane elastomer.

3. The method of claim 1, wherein the polymer composition comprises a second polyester-polyurethane elastomer whose isocyanate component does not comprise naphthalene-1,5-diisocyanate but comprises methylene diphenylene diisocyanate and / or toluene diisocyanate. 4 . The method according to claim 3 , wherein the mass proportion of the first polyester-polyurethane elastomer is 60% to <100%, based on the total mass of the first and second polyester-polyurethane elastomers.

5. The method according to claim 3 or 4, wherein the polymer composition does not comprise other polyester-polyurethane elastomers besides the first and second polyester-polyurethane elastomers.

6. The method according to any one of the preceding claims, wherein the mass proportion of the polyester-polyurethane elastomer in the polymer composition is from 60% to 100%.

7. The method according to claim 6, wherein the portion of the polymer composition not derived from the polyester-polyurethane elastomer comprises a polyurethane based on a polyol component comprising a polyether polyol and / or a polycarbonate polyol and an isocyanate component comprising methylene diphenylene diisocyanate and / or a toluene diisocyanate.

8. The method according to any one of the preceding claims, comprising: (D) further reacting the carbamate isolated in (C), wherein the further reaction comprises one of the following: (DI) hydrolyzing the carbamate with water in the presence of a hydrolysis catalyst to form naphthalene-1,5-diamine and a linear primary monoalcohol; (D.II) cleavage of carbamates into naphthalene-1,5-diisocyanate and linear primary monools; (D.III) hydrogenolyzing the carbamate with hydrogen in the presence of a hydrogenolysis catalyst to form naphthalene-1,5-diamine and a linear primary monohydric alcohol; or (D.IV) The urethane is reacted with a polyol in the presence or absence of a catalyst to obtain an OH-terminated prepolymer. 9 . The process according to claim 8 , comprising (DI) or (D.III), wherein naphthalene-1,5-diamine, optionally after purification, is reacted with phosgene to give naphthalene-1,5-diisocyanate.

10. The method according to any one of the preceding claims, wherein step (C) comprises: The solid carbamate phase is separated from the liquid alcohol phase, optionally subsequently washed and, if necessary, subjected to further purification steps in order to isolate the carbamate.

11. The process according to claim 10, comprising post-processing the liquid alcoholic phase according to one of the following variants (EI), (E.II) and (E.III), Among them (EI) includes: (EIa) extracting the liquid alcoholic phase with an organic and / or aqueous extractant and separating it into a nonpolar phase and a polar phase, optionally after distillative separation of the linear primary monohydric alcohol contained therein; (EIb) optionally evaporating the optional extractant and / or the optional linear primary monohydric alcohol from the non-polar phase to leave a concentrated organic phase; (EIc) reacting the nonpolar phase or the concentrated organic phase with hydrogen in the presence of a hydrogenolysis catalyst to produce an alcohol; and optionally (EId) further purifying the alcohol by distillation; Among them (E.II) includes: (E.II.a) reacting a liquid alcohol with hydrogen in the presence of a hydrogenolysis catalyst, wherein the linear primary monohydric alcohol is separated off by distillation before and / or after the reaction with hydrogen, thereby leaving an alcohol mixture; and (E.II.b) separating the alcohol mixture into individual alcohol fractions by distillation; and wherein (E.III) includes: The liquid alcohol phase is used to synthesize polyester.

12. The process according to claim 11, comprising variant (EI), wherein the alcohol from (EIc) or (EId) is used for the synthesis of polyester.

13. The process according to claim 11, comprising variant (EI), or the process according to claim 12, wherein the polar phase is post-treated to obtain the alcohol component of the polyester component and / or the optional chain extender and / or crosslinker.

14. The process according to claim 13, wherein the alcohol component obtained from the polar phase and / or the chain extender and / or crosslinker obtained from the polar phase are used to produce new polyester-polyurethane elastomers.

15. The process according to claim 11, comprising variant (E.II), wherein one or more alcohol fractions from (E.II.b) are used for the synthesis of polyesters.

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