PROCESS FOR THE DECOMPOSITION OF POLYURETHANE

Abstract

The invention relates to a method for decomposing polyurethane, wherein material containing polyurethane is heated to a temperature from 190? C. to 250? C. under overpressure in the presence of an aqueous solution containing 1 to 45 mass percent urea. It further relates to a liquid process medium obtainable thereby.

Claims

1. A method for decomposing polyurethane, wherein a polyurethane-containing material is heated to a temperature from 190? C. to 250? C. under overpressure in the presence of an aqueous solution containing 1 to 45 mass percent urea.

2. The method according to claim 1, wherein heating takes place under a pressure from 1.05 bar to 100 bar.

3. The method according to claim 1, wherein the overpressure is an equilibrium pressure established upon heating.

4. The method according to claim 1, wherein the heating takes place over a period from 20 minutes to 240 minutes.

5. The method according to claim 1, wherein the aqueous solution comprises 2.5-10 mass percent urea, and the heating takes place over a period from 45-250 min, in particular over a period from 45 to 240 min.

6. The method according to claim 1, wherein the ratio between urea-containing aqueous solution and polyurethane-containing material has a value from 0.4 ml/g to 5 ml/g.

7. The method according to claim 1, wherein after heating at least some of the liquid process medium obtained is recovered.

8. The method according to claim 7, characterized in that solids are removed from the recovered liquid process medium.

9. The method according to claim 1, wherein the aqueous solution is free from polyols and/or free from carboxylic acid and/or free from ammonia.

10. The method according to claim 1, wherein the aqueous solution consists of water and urea.

11. A liquid process medium, obtainable with a method according to claim 1, wherein the heating takes place at a temperature from 190? C. to 250? C. over a period from 20 minutes to 240 minutes, wherein the aqueous solution contains 1 to 10 mass percent urea and the ratio between urea-containing aqueous solution and polyurethane-containing material has a value from 0.4 ml/g to 5 ml/g.

Description

[0066] Further advantages, features and particularities are discernible from the following description, in whichoptionally with reference to the figuresat least one exemplary embodiment is described in detail.

[0067] FIG. 1 shows a three-dimensional chart representing the degree of decomposition of polyurethane-containing material as a function of temperature and period for which the method is carried out.

[0068] FIG. 2 shows a three-dimensional chart representing the influence of urea on the decomposition of various polyurethane-containing materials for a selected heating duration.

[0069] FIG. 3 shows a three-dimensional chart representing the influence of urea on the decomposition of a polyurethane-containing material in a time series.

Example 1-Polyurethane Soft Foams

[0070] Two polyurethane soft foams with TDI base or MDI base (Product designations: R 4030 and R 5535, Source: Eurofoam Deutschland Gmb H Schaumstoffe, Wiesbaden, Deutschland) weighing 20.0 g and 19.6 g respectively were absorbed respectively in 32.2 ml and 35.7 ml 7.5-% urea solution, and treated for 180 minutes at 190? C. in a closed pressure vessel.

TABLE-US-00001 TABLE 1 Initial weight of Urea content of Volume of polyurethane the aqueous aqueous soft foam sample solution solution used Decomposition [g] [mass %] [ml] [%] 20.0 (R 4030) 7.5 32.2 50 19.6 (R 5535) 7.5 35.7 90 180 min at 190? C.

[0071] The samples taken were allowed to cool, and then classified semi-quantitatively by visual assessment of the degree of decomposition of solid polyurethane, and corresponding disappearance of observable solid material and conversion into the liquid process medium, wherein (as in all other subsequent experiments) 0% signifies that no decomposition of polyurethane had yet taken place, and accordingly the quantity of solid polyurethane originally used was still present in its entirety, while 100% stands for complete decomposition and corresponding conversion of the polyurethane into the liquid process medium.

[0072] In both cases, partial decomposition took place, wherein differing quantities of solids were still present in the liquid process medium in the form of evidently condensed foam residues.

Example 2-Polyurethane Integral Foam

[0073] Two samples of flexible polyurethane integral foam, one with ether base and one cast elastomer marketed under the brand name Colo-Fast? (BASF, SE, Ludwigshafen, German) originally weighing 25 g and 35 g respectively were absorbed in 40 ml 3% urea solution, and treated for 240 minutes at 245? C. in a closed pressure vessel filled to 80% capacity.

TABLE-US-00002 TABLE 2 Initial weight of Urea content of Volume of polyurethane the aqueous aqueous integral foam sample solution solution used Decomposition [g] [mass percent] [ml] [%] 25 (Ether base) 3 40 100 35 (Colo-Fast) 3 40 100 240 min at 245? C.

[0074] Complete decomposition of the polyurethane-material used took place, although a small fraction of particles was observed, possibly attributable to polymerisation.

Example 3-Non-Foamed Polyurethane

[0075] Solid, non-foamed polyurethanes were used in series of tests for the decomposition method. For these tests, blue plastic polyurethane hoses of type PUN (Festo Gesellschaft m.b.H, Vienna, Austria) were comminuted, and 1 g of each was heated to 210? C. in 25 ml of an aqueous urea solution with a urea content of 1 mass percent, 5 mass percent, 7.5 mass percent and 10 mass percent in a closed pressure vessel for a period of 150 minutes.

[0076] The test series served essentially to determine the influence of the urea concentration and to calculate the decomposability of solid polyurethanes.

TABLE-US-00003 TABLE 3 Initial weight of Urea content of Volume of polyurethane the aqueous aqueous hose sample solution solution used Decomposition [g] [mass percent] [ml] [%] 30 1 25 100 30 5 25 100 5 7.5 20 100 5 7.5 20 100 30 7.5 25 100 30 10 25 100 150 min at 210? C.

[0077] As a result, it was found that no fractions of the originally used solid polyurethane were observable in any of the samples. Thus, non-foamed polyurethanes are decomposable under the stated experimental conditions.

Example 4-Duroplastic Polyurethane

[0078] As a further example of non-foamed polyurethanes, a duroplast polyurethane core with a volume weight of 165 g/l, as is used in skis, was used for the decomposition method. The core was comminuted, and 15 g thereof in 40 ml of an aqueous urea solution with a urea content of 3 mass percent was heated to 210? C. for a period of 150 minutes in a closed pressure vessel with fill volume of 80% of the available capacity (remaining volume 20%: air).

TABLE-US-00004 TABLE 4 Initial weight of Urea content of Volume of polyurethane ski the aqueous the aqueous core material sample solution solution used Decomposition [g] [mass percent] [ml] [%] 15 3 40 100 150 min at 210? C.

[0079] As a result, it was found that no fractions of the originally used non-foamed polyurethane were observable any longer in the liquid phase obtained.

Example 5-Elastomeric Polyurethanes

[0080] As examples of elastomeric polyurethanes, springs made of microcellular polyurethane, which are marketed under the brand name Cellasto? (BASF, SE, Ludwigshafen, Germany), and the cast elastomer Colo-Fast? (BASF SE, Ludwigshafen, Germany) were used. The samples were comminuted and heated to 210? C. in separate lots in 40 ml of an aqueous urea solution with a urea content of 3 mass percent for a period of 150 minutes in a closed pressure vessel with fill volume of 80% of the available capacity (remaining volume 20%: air).

TABLE-US-00005 TABLE 5 content Initial weight of elastomeric Urea content of Volume of polyurethane the aqueous aqueous sample solution solution used Decomposition [g] [mass percent] [ml] [%] 35 (Cellasto? 3 40 100 (sample 1) 40 (Cellasto? 3 40 100 (sample 2) 35 (Colo-Fast?) 3 40 100 150 min at 210? C.

[0081] As a result, it was found that no fractions of the originally used elastomeric polyurethane were observable any longer in the liquid phase obtained.

Example 6-Time Series

[0082] In a test series, the R 4030 and R 5535 polyurethane foams described previously were heated in an aqueous urea solution with a urea content of 7.5 mass percent at a temperature of 230? C. in a closed pressure vessel for 60 minutes, 90 minutes or 120 minutes.

TABLE-US-00006 TABLE 6 Initial Urea content Volume of weight of of the aqueous polyurethane aqueous solution foam sample solution used Duration Decomposition [g] [mass %] [ml] [min] [%] 9.98 (R 4030) 7.5 25 60 50 10.47 (R 5535) 7.5 25 60 50 9.93 (R 4030) 7.5 25 60 50 10.36 (R 5535) 7.5 25 60 50 10.08 (R 4030) 7.5 25 90 90 10.04 (R 5535) 7.5 25 90 90 10.15 (R 4030) 7.5 25 120 100 10.23 (R 5535) 7.5 25 120 100 Various periods at 230? C.

[0083] At the decomposition rate classified as 50%, the foam structures were transformed into a solution, resulting in a paste-like consistency, at the decomposition rate classified as 90%, the foam structure was almost completely liquefied, at 100 percent decomposition, it was entirely liquefied.

Example 7-Time Series and Temperature Series

[0084] Given that the preceding experiments had shown that in principle any type of polyurethane-containing material can be decomposed with the method, in a new series of experiments with the aim of making a systematic calculation of a temperature-dependency and time-dependency of the decomposition, a mixture of different polyurethane-containing materials was used, specifically a mixture of identical proportions by weight, each having an original weight of 4.15 g. [0085] a) Standard foam grade TDI 80-based with filler material (calcium carbonate) and SAN polymer particles (N 4045 WS), [0086] b) High resilience (HR) polyurethane foam grade TDI 80/TDI65-based with filler material (calcium carbonate) and SAN polymer particles (R 4040 WS), [0087] c) High resilience (HR) polyurethane foam grade MDI-based with filler material (calcium carbonate) and SAN polymer particles (R 5535 WS), and [0088] d) Viscoelastic foam grade MDI-based-V5018 WS, Eurofoam Deutschland GmbH Schaumstoffe) with no filler materials.

[0089] The polyurethane-containing material obtained in this way was reacted in shredded form with a 3% urea solution in a ratio of 0.582 ml urea solution per gram of polyurethane-containing material. In order to run the temperature series, samples in closed pressure vessels with an equilibrium pressure set were heated to 190? C., 210? C., 230? C. and 245? C. in a heat cabinet, and were removed after a residence time of 60 minutes, 90 minutes, 120 minutes, 180 minutes and 240 minutes at the respective temperature. Three samples were tested and evaluated in parallel for each time point.

[0090] The samples that were removed were allowed to cool and then classified semi-quantitatively by visual assessment to obtain an average value for each set of three samples, with regard to the degree of decomposition of solid polyurethane and the corresponding disappearance of observable solid material and conversion to the liquid process medium. The result is represented in FIG. 1, wherein the duration of the heat treatment at a given temperature is plotted in minutes along the horizontal x-axis, the semi-quantitative degree of decomposition is indicated as a percentage on the perpendicular z-axis, and the three selected temperatures of 190? C., 210? C., 230? C. and 245? C. are plotted on the y-axis which progresses into the image plane. It is evident that higher rates of decomposition can be achieved more quickly as the temperature increases to 245? C.

Example 8-Control Experiment without Overpressure

[0091] In a control experiment, two separate samples, consisting of 2 g TDI polyurethane foam (Product designator: R 4030; Source: Eurofoam Deutschland GmbH Schaumstoffe, Wiesbaden, Germany) and MDI polyurethane foam (Product designator: R 5535; Source: Eurofoam Deutschland GmbH Schaumstoffe, Wiesbaden, Germany) were each reacted with 40 ml 7.5% urea solution and in a glass flask were treated at a temperature from 100? C. to 110? C. under ambient pressure in a heat cabinet, wherein the loss of liquid was supplemented by the addition of water. After 4.5 hours no decomposition of any kind was observed.

Example 9-First Control Experiment without Urea, with Overpressure

[0092] As a further control experiment, four different samples: [0093] 16.6 g black PUR integral foam (window insulation material) in 9.66 ml H.sub.2O, [0094] 16.6 g white PUR integral foam (component of shoe) in 9.66 ml H.sub.2O, [0095] 14.0 g PUR semi-hard foam (BASF) in 8.15 ml H.sub.2O, and [0096] 16.0 g PUR elastomer (Cellasto? from BASF) in 9.66 ml H.sub.2O
were each heated for 30 min at 245? C. in closed pressure vessels, wherein the water quantities indicated either contained no urea or 3 mass percent urea.

[0097] The results are represented in FIG. 2, wherein the samples listed above are identified as PUR integral window, PUR integral shoe, PUR-semi-hard and PUR elastomer. The degree of conversion is indicated as a percentage on the y-axis. It was found that in all cases a significant increase in decomposition could be achieved with the addition of urea.

[0098] In the case of the integral foams and the elastomer, it was possible to initiate complete or almost complete decomposition of the solid material by this means, and even in the case of the PUR semi-hard foam, which was decomposed less completely after a heat treatment duration of 30 minutes, a clear increased in the rate of decomposition was still recorded following the addition of urea. The less effective decomposition of the semi-hard foam might be caused by poorer heat transfer within the foam material since the semi-hard foam with a volume weight of 133 g/L has considerably lower density than PUR integral window (850 g/L), PUR integral shoe (790-830 g/L) and PUR elastomer (400-550 g/L). To this extent, the PUR semi-hard foam occupied much more space inside the pressure vessel, and was therefore wetted less effectively with the urea-free and the urea-containing aqueous solution, thus making the heat transfer more difficult due to the greater volume of air in the pores.

Example 10-Second Control Experiment without Urea, with Overpressure

[0099] In a further control experiment, multiple samples of a mixture of polyurethane soft foams (either 16.6 g in 9.66 ml water pr 16.6 g in 9.66 water containing 3 mass percent urea) were heated at 245? C. in closed pressure vessels and removed at different time points (40, 60, 90, 120, 180 and 240 min). Compared with the samples used in Example 9, in terms of material properties the mixture of polyurethane soft foams was most similar to the PUR semi-hard foam. The results are represented in FIG. 3, wherein the time point in minutes is indicated on the x-axis and the degree of conversion in percent is indicated on the y-axis. It was found that in the presence of 3 mass percent urea complete decomposition was recorded after a heating duration of just 40 minutes, whereas in urea-free water only partial decomposition had occurred after 40 minutes, and while this also increased as the heating period progressed, in each case it lay below the decomposition that could be achieved with treatment using urea-containing water.

Example 11-Experiment with Simply Structured Soft Foam System (Single Polyol Foam), Analysis of Products of Decomposition

[0100] In order to determine the products of decomposition produced after the method was implemented, a polyurethane soft foam with the simplest possible chemical structure was produced in the laboratory (Table 7). In order to maintain a distinction between the influencing factors, only one standard ether polyol with a molecular weight 3500 MW was used, and toluene diisocyanate TDI 80 was implemented as the isocyanate. The volume weight of the foam was 22 kg/m.sup.3

TABLE-US-00007 TABLE 7 Parts by Raw material weight Polyol Standard Ether (3500 MW) 100 Amin BDE - Dabco BL 11 (Evonik Industries, Essen, Germany 0.1 Amin TEDA - Dabco 33 LV Evonik Industries, Essen, Germany 0.22 Silikon Niax L 620 (Momentive Performance Materials, 0.48 D-Leverkusen Water, metered 4.48 Tin octoate, pure 0.15 TDI 80 50.81

[0101] This PUR soft foam was comminuted and processed using the method in a 11.5 litre B?chi reactor (B?chi A G, Uster, Switzerland). 400 gram foam were pre-moistened with 236 millilitres of a 3% water-urea solution and poured into a stainless steel digestion vessel (also called an Inliner vessel) with a volume of about 10.2 litres. The bottom of the vessel was lined with aluminium foil having a rim height of 5 cm to catch the liquid process medium produced. 200 ml water was placed below the Inliner vessel inserted in the reactor in order to generate water vapour rapidly. The method according to the invention was conducted for a period of 240 min, the reactor shell temperature initially being set 260? C. for 60 min, and subsequently to 250? C. for 180 min. By this process, the inner chamber of the reactor reached a temperature of just below 230? C. (229.3? C.).

[0102] In order to carry out a chemical analysis of the process medium obtained, 1 ml of the medium was dissolved in 99 ml acetonitrile and mixed on a laboratory vibrating plate for 24 h. Then, the acrylonitrile sample mixture was filtered with a syringe filter (e.g. Chromafil Xtra, RC, 25 mm, 0.45 ?m) before 1-5 microlitres of the sample were introduced directly into a gas chromatography system of type Agilent 8890 GC (Agilent, Santa Clara, USA). The GC column was initially maintained for 2 minutes at 40? C., and then warmed from 40? C. to 250? C. at a heating rate of 10 Kelvin per minute. At the end, a hold time of 5 minutes was added. In all, the measurement time lasted 28 minutes. The measurement was taken with a 1:10 split. The method is named Ramp40-250_28min_1.5ml_split1-10.M. The spectrum that was measured with the coupled Agilent 5977B GC/MSD mass spectrometer system shows two prominent peaks at retention times 1.37 to 1.75 minutes and 13.71 minutes. The spectra were analysed using the NIST17 software package, which was included in the scope of delivery of the TG/STA-GC-MS system that is described in greater detail in the context of Example 12 (National Institute of Standards and Technology, Gaithersburg, USA), and also included the AMDIS32 software for qualitative GC-MS analyses, the databases ALKANES, NISTCW, NISTDRUG, NISTEPA, NISTFAD, NISTFF, NISTTOX and PESTPLUS, and the MSSEARCH software, wherein this last software program can be used to selectively compare individual measured scans with the databases used. The analysis of the peaks is shown in Table 8,

[0103] wherein MF (Match Factor) stands for comparing the measured spectrum with the spectra in the databases, and RFM (Reverse Match Factor) means comparing the available database spectra with the measured spectrum. In both cases, a special algorithm stored in the software is used. These factors are standardised to 1000=100% match in the NIST software.

TABLE-US-00008 TABLE 8 Retention time [min] Substance MF RMF 1.37 Acetonitrile (CAS 75-05-8) 897 900 1.75 Acetonitrile (CAS 75-05-8) 912 914 13.71 1,3-Benzenediamine, 4-methyl-(CAS 95-80-7) 962 963

[0104] The acetonitrile may be attributed to the solvent used, acetonitrile. A synonym for the 1,3-Benzenediamine, 4-methyl-(CAS 95-80-7) is 2,4-Diaminotoluene. The 2,4-Diaminotoluene peak indicates that this compound can be obtained in the course of the method according to the invention. 2,4-Diaminotoluene is a precursor of toluene diisocyanate TDI 80, into which it can be converted by phosgenation, and thus represents an industrially valuable, reusable raw material, particularly in the context of the polyurethane economy.

[0105] A Gel Permeation Chromatography (GPC) analysis was also performed on the process medium to determine its molecular weight (external measurement at BASF Lemf?rde-Central Analytic Lemf?rde, BASF Polyurethanes GmbH, Elastogranstr 60, 49448 Lemfoerde, Germany).

[0106] In the course of this analysis, a molar mass distribution with a pronounced main peak at 3700 g/mol was measured. The viscosity of the process medium was also determined. It has a value in the order of 1100 mPas. The OH number of the process medium was also determined and found to be 325 mg KOH/g.

[0107] The results supported the theory that a substantial component of the process medium is represented by polyol. Its molar mass is very similar to that of the polyol used originally, and (possibly due to the treatment it underwent during the method) has a slightly higher viscosity (Polyol Standard Ether ?3500 MW=25 700?900 mPa.Math.s, OH 48) and a higher OH number.

[0108] Accordingly, the method according to the invention may be used to recover polyols and return them for reuse as valuable raw materials.

Example 12-Experiment with PUR Soft Foam Mixture, Analysis of the Products of Decomposition by TG-GC/MS

[0109] This example represents an attempt to demonstrate that polyols produced in the course of the method according to the invention were present in the process medium obtained. To this end, the process medium was to be thermally decomposed at temperatures of about 380? C., allowing a statement to be made regarding the presence of polyols in the process medium from the products of decomposition obtained thereby. To do this, the path was chosen via coupled TG/STA-GC-MS measurements (coupling of gas chromatography mass spectrometer with thermal analysis, wherein TG stands for thermogravimetry and STA for simultaneous thermal analysis). The measuring instruments used were a STA 449 F3 Jupiter (Netzsch, Selb, Germany) which was connected to the Agilent 8890 GC type gas chromatography system (Agilent, Santa Clara, USA) and the Agilent 5977B GC/MSD mass spectrometer system via a heated transfer line.

[0110] First, in a preparatory step, a reference database was created as follows.

[0111] For this, the polyols listed in Table 9 below were used, as these represent constituent components of the soft foams used in mixture actually analysed later with reference to the database (see Table 10).

TABLE-US-00009 TABLE 9 Polyol Suffix in the AMDIS database Standard 3500 MW STD_POLYOL Standard 45% SAN Polyol SAN_45% HR 6000 MW Polyol HR_6000 HR 25% SAN Polyol HR_SAN HR high functional Polyol HR_HF Hypersoft Polyol HYPERSOFT Viscoelastic Polyol VE8420

[0112] These were each decomposed individually at 380? C. in the thermal decomposition stage of the TG/STA-GC-MS system described previously. The main peaks were determined with the databases from NIST and AMDIS (see Example 11), and the name of the assigned compound according to these databases and the GC retention times of the decomposition products were stored in the reference database, and the appropriate suffix according to Table 9 was assigned to each decomposition product. If the same decomposition products occurred with different polyols, the respective suffix was added. These decomposition products with the corresponding identifying product code are then listed in Table 11 (wherein in Table 11 the decomposition products of the mixture according to Table 10 are shown).

[0113] After the reference database was created, in order to answer the question of the extent to which polyols appear in the process medium after the method according to the invention has been carried out, a mixture of soft foams was subjected to the method according to the invention.

[0114] For this purpose, 400 gram of a mixture of soft foams were processed with the method according to the invention in the 11.5 litre Buchi reactor. The mixture had the following soft foam qualities (obtained from Neveon Holding GmbH, Ebersbach-Fils, Germany):

TABLE-US-00010 TABLE 10 Soft foam Class Quantity [g] N 3045 TDI 80 - standard 100 R 4040 TDI 80 - high resilience 100 R 5535 MDI - high resilience 100 V 5018 MDI - viscoelastic 100

[0115] The 400 grams of foam mixture were pre-moistened with 236 millilitres of a 3% water-urea solution and poured into a stainless steel (volume approx. 10.2 litres). The bottom of the vessel was lined with aluminium foil having a rim height of 5 cm to catch the liquid process medium produced. 200 ml water was placed below the Inliner vessel in order to generate water vapour rapidly.

[0116] The method was carried out over a period of 240 min, the reactor shell temperature initially being set 260? C. for 60 min, and subsequently to 250? C. for 180 min. By this process, the inner chamber of the reactor reached a temperature of just under 236? C.

[0117] The process medium recovered was again analysed with coupled TG/STA-GC-MS measurements.

[0118] The spectrum at 379? C. was analysed with AMDIS and with the reference database created in the preparatory step with a default Minimum Match Factor (MF) setting of 80%. The match factor refers to the agreement between the measured spectrum and the spectra from the AMDIS databases expressed as a percentage. This factor is calculated by algorithms stored in the software. The main peaks correspond to the peaks that were measured for the single polyols according to Table 9. The correlation of this data is presented in Table 11. The analysis result shows that the process medium contains polyols that were used originally as well as conversion products and/or products of decomposition that were produced in the course of the decomposition method.

TABLE-US-00011 TABLE 11 Retention time [min] Substance MF 2.4464 Ethanol, 2-methoxy-, acetate_STD_POLYOL (CAS#: 110-49-6) 83 IUPAC: 2-methoxyethyl acetate 3.9042 1-Propene, 2-(1-methylethoxy)_HR_6000 (CAS#: 4188-63-0) 93 IUPAC: (E)-1-propan-2-yloxyprop-1-ene 6.5138 Diisopropylether_HR_SAN (CAS#: 108-20-3) 99 6.9436 2-Propanone, 1-(1-methylethoxy)-_STD_POLYOL_HR_HF_VE8420 100 (CAS#: 42781-12-4) 1-Isopropoxyacetone IUPAC: 1-propan-2-yloxypropan-2-one 7.4102 Oxirane, trimethyl-_HR_6000 (CAS#: 5076-19-7) 98 Trimethyloxiran IUPAC: 2,2,3-trimethyloxirane 7.6279 Carbonic acid, allyl 2-ethoxyethyl ester_HR_6000 93 (NIST#: 357377) (ID#: 2-87-3) 8.3387 Styrene_SAN_45%_HR_SAN (CAS#: 100-42-5) 97 Styrol 9.4547 Diisopropyl ether_HR_6000_HR_HF (CAS#: 108-20-3) 99 9.5666 3-Pentanol, 2-methyl-_HR_6000_HR_HF (CAS#: 565-67-3) 98 IUPAC: 2-methylpentan-3-ol 9.9325 2-Pentanone, 5-methoxy-_STD_POLYOL_HR_HF_VE8420 (CAS#: 17429-04-8) 89 IUPAC: 5-methoxypentan-2-one 10.1310 Ethanol, 2-(2-ethoxyethoxy)-_HYPERSOFT (CAS#: 111-90-0) 98 Diethylene glycol monoethyl ether 11.3633 1-Propanol, 3-[3-(1-methylethoxy)propoxy]-_STD_POLYOL_HR_SAN_HR_HF 99 (CAS#: 54518-03-5) IUPAC: 3-(3-Isopropoxypropoxy)propan-1-ol 11.4137 1-Propanol, 2-(2-hydroxypropoxy)-_VE8420 (CAS#: 106-62-7) 94 IUPAC: 2-(2-hydroxypropoxy)propan-1-ol 11.5686 Propane, 1,1-dipropoxy-_STD_POLYOL_HR_HF 98 (CAS#: 4744-11-0) Dipropylpropylal 11.9289 1-Butoxypropan-2-yl isobutyl carbonate_HR_6000_HR_HF 98 (NIST#: 378276) (ID#: 26899) 13.0548 1-Propanol, 2,2-oxybis-_STD_POLYOL_VE8420 96 (CAS#: 108-61-2) 2,2-Oxydipropanol 13.2251 Ethanol, 2-12-(2-ethoxyethoxy)ethoxy]-_HR_6000_HR_HF 83 (CAS#: 112-50-5) Triethylene Glycol Monoethyl Ether 13.3345 12-Crown-4 HR_6000_VE8420 (CAS#: 294-93-9) 94 1,4,7,10-Tetraoxacyclododecan 13.9039 Diethyl carbitol_HYPERSOFT (CAS#: 112-36-7) 83 Diethyler et yylether 14.2187 Tri(propylene glycol) propyl ether_STD_POLYOL 81 (CAS#: 96077-04-2) 14.5563 2-Propanol, 1-[1-methyl-2-(2-propenyloxy)ethoxy]- 94 STD_POLYOL_VE8420 (#: 55956-25-7) 15.5887 Tripropylene glycol monomethyl 81 ether_STD_POLYOL_VE8420 ( CAS#: 20324-33-8) 16.5011 Benzene, 1,1-(1,3-propanediyi)bis-_SAN_45% (CAS#: 1081- 89 75-0) 1,3-Diphenylpropan 17.6774 4,8,12,16-tetraoxaeicosan-1-ol_HR_6000_HR_HF 96 (NIST#: 397636) (ID#: 32-16-4) IUPAC: 3-13-[3-(3-butoxypropoxy)propoxy|propoxy]propan-1-ol 17.8010 Pentaethylene glycol_HR_SAN (CAS#: 4792-15-8) 92 19.5699 3,6,9,12-Tetraoxatetradecan-1-ol_HYPERSOFT (CAS#: 5274-68-0) 85 IUPAC: 2-[2-[2-(2-dodecoxyethoxy)ethoxy]ethoxy]ethanol Tetraethyleneglycol monododecyl ether 19.5699 Tetraethylene glycol diethyl ether_HYPERSOFT 85 (CAS#: 4353-28-0) IUPAC: 1-ethoxy-2-12-12-(2-ethoxyethoxyjethoxy ethoxyjethane 3,6,9,12,16-Pentaoxaheptadecane 19.5988 1,4,7,10,13,16-Hexaoxacyclooctadecane 84 HYPERSOFT_HR_6000 (CAS#: 17455-13-9) 18-Crown-6 ether 19.6542 3-Phenylpropanol_SAN_45% (CAS#: 122-97-4) 81 IUPAC: 3-phenylpropan-1-ol Benzenepropanol 19.9315 (1-Benzyl-2-O-tolyl-ethyl)-isonitrile_SAN_45% 82 (NIST#: 287385), (ID#: 88-42-6) IUPAC: N-11-(2-methylphenyl)-3-phenylpropan-2-yl]methanimine

[0119] The spectrum at 265? C. was analysed with AMDIS and with the databases of AMDIS and NIST with a default Minimum Match Factor (MF) setting of 90%. In prior experiments, it was discovered that at a temperature of 265? C. the components contained in the process medium that can be traced back to the diisocyanate in the polyurethane are broken down thermally, while components in the polyurethane that can be traced back to the polyols are not broken down at this temperature.

[0120] The main peaks correspond to the diamine precursors of the diisocyanates used in the soft foams (Table 12). The liquid process medium obtained after the method according to the invention has been carried out thus contains the precursors from before the industrial step of phosgenation of the diisocyanates.

TABLE-US-00012 TABLE 12 Retention time [min] Substance MF 9.7657 Aniline 99 14.2512 1,3-Benzenediamine, 4-methyl- 98 14.2727 1,3-Benzenediamine, 4-methyl- 98 18.9949 Benzenamine, 4,4-methylenebis- 92 19.4296 Benzenamine, 4,4-methylenebis- 100 19.8471 Benzenamine, 4,4-methylenebis- 98

[0121] The described method enables the of decomposition polyurethane and is therefore commercially applicable. Moreover, raw materials can be recovered from the process medium obtained, and these may be used again in the chemical industry, in particular they are useful to the polyurethane-recycling economy.

[0122] Although the invention has been illustrated and explained in greater detail with the aid of preferred embodiments thereof, the invention is not limited by the disclosed examples, and other variations may be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention. It is therefore evident that a multiplicity of variation possibilities exist, and that the variants identified, or elements thereof, can be combined with each other. It is also evident that variants identified for exemplary purposes really do only represent examples, which are not to be interpreted in any way as constituting a limitation of the range of protection, the application possibilities or the configuration of the invention. Rather, the preceding description and the description of the figures are designed to enable the person skilled in the art to reproduce the exemplary embodiments in concrete terms, wherein the person skilled in the art with knowledge of the disclosed inventive thought is able to introduce many changes, for example with regard to the function or arrangement of individual elements identified in an exemplary variant without departing from the scope of protection of the invention, which is defined by the claims and their legal counterparts, such as more detailed explanations in the description.