A new method for depolymerizing polyurethanes.

Abstract

The present invention relates to a new and improved process for the depolymerization of polyurethanes that allows for high yield recovery of polyether polyols and polyamines.

Description

[Technical Field]

[0001] The present invention relates to a new and improved process for the depolymerization of polyurethanes that allows for high yield recovery of polyether polyols and polyamines. [Background technology]

[0002] Polyurethanes are highly useful materials in the production of rigid and flexible foams, solid and microcellular elastomers, sealants, coatings, and adhesives. Their versatility, relatively low cost, and excellent properties have led to rapid growth in the polyurethane industry over the past 50 years. Currently, thousands of tons of polyurethane are produced annually worldwide. Unfortunately, most polyurethanes are thermoset materials that are crosslinked to some degree. Therefore, unlike thermoplastics such as polyethylene, polypropylene, and polystyrene, scrap or waste polyurethanes cannot be easily remelted or reprocessed into useful articles. Because it is highly desirable for economic and environmental reasons to reuse or recover the large amounts of scrap or waste polyurethane generated each year rather than incinerating or disposing of it in landfills, considerable inventive effort has been devoted to devising methods for recovering useful chemical components from scrap polyurethane materials.

[0003] Glycolysis is used to regenerate, or depolymerize, PU (polyurethane) waste, including both hard and soft products. This process requires various steps, including (1) crushing, (2) stepwise addition of the waste to diethylene glycol in the presence of a catalyst, (3) alkoxylation, and (4) degassing and filtration to recover the polyol.

[0004] Polyurethane foam scrap can also be regenerated via ammonolysis and aminolysis processes by using ammonia, amines, or alkanolamines to recover the monomer polyols, which can then be reused in the synthesis of PU. For example, German Patent Application No. 102006036007 describes a method in which polyurethanes and polyureas are recycled via aminolysis.

[0005] Acidolysis methods have also been suggested for recycling polyols. These methods have not yet been used on a large industrial scale. They are very complex and expensive, requiring high temperatures and pressures, and the amine quality of each recycled polyol is poor, so only small amounts can be used with large amounts of virgin raw material to produce new polyurethane foams.

[0006] Hydrolysis methods have also been tested in the prior art for depolymerizing polyurethanes. However, as known in the art, polyurethane hydrolysis methods using base catalysts to recover polyether polyols and polyamines suffer from several drawbacks. At relatively low temperatures, the hydrolysis rate is slow and reportedly incomplete. At higher temperatures, the rate is faster, but certain undesirable side reactions may occur. For example, U.S. Pat. No. 5,208,379 proposes a method for hydrolyzing polyurethanes prepared by reacting active hydrogen-containing polyethers and organic polyisocyanates, comprising contacting the polyurethane with water in the presence of an effective amount of a strong base selected from the group consisting of alkali metal oxides, alkali metal hydroxides, alkaline earth metal oxides, and alkaline earth metal hydroxides, and an effective amount of an activator selected from the group consisting of quaternary ammonium salts containing at least 15 carbon atoms and organic sulfonates containing at least 7 carbon atoms, for a time and temperature effective to produce active hydrogen-containing polyethers and organic polyamines. Although U.S. Pat. No. 5,208,379 discloses in the general description that the reaction temperature can be selected in the range of 80 to 225° C., Example 19 shows that only partial hydrolysis occurred at 120° C., and Example 18 shows that the yield was only 70% at 140° C. Therefore, the process of U.S. Pat. No. 5,208,379 cannot be used economically at lower temperatures. Therefore, there remains a strong need to provide a more efficient method for polyurethane regeneration to recover polyether polyols and / or polyamines in good quality and good yield. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Patent Application Publication No. 102006036007 [Patent Document 2] U.S. Patent No. 5,208,379 Summary of the Invention [Problem to be solved by the invention]

[0008] The subject of the present invention was to provide a new process for the depolymerization of polyurethanes which overcomes the above-mentioned drawbacks of the prior art processes.

[0009] A particular problem of the present invention was to provide a process that can be operated at lower temperatures with good yields compared to the prior art.

[0010] A further specific problem to be solved by the present invention was to provide a process that makes it possible to obtain polyether polyols and / or polyamines in a quality very close to that of the raw materials used to produce the reclaimed polyurethanes. It should be possible to use a high proportion of the recovered polyether polyols and / or polyamines for the production of new polyurethanes. [Means for solving the problem]

[0011] Further problems solved by the present invention, but not previously described, can be derived from the following description, examples, figures and claims.

[0012] The present inventors have surprisingly discovered a method for hydrolyzing polyurethanes, preferably prepared by reacting an active hydrogen-containing polyether and an organic polyisocyanate, which method produces a polyisocyanate having a pK of less than 1 at 25°C. bIt has been found that a process comprising contacting the polyurethane with water in the presence of a strong inorganic base having a value of 1 to 6 carbon atoms and a quaternary ammonium salt containing an ammonium cation containing from 6 to 14 carbon atoms if the ammonium cation does not contain a benzyl residue, or from 6 to 12 carbon atoms if the ammonium cation contains a benzyl residue, makes it possible to obtain active hydrogen-containing polyethers, preferably polyether polyols, and organic polyamines in high yields.

[0013] It was particularly surprising that, in contrast to the teachings of US Pat. No. 5,208,379, ammonium cations having a lower number of carbon atoms resulted in higher yields at lower reaction temperatures.

[0014] The recovered active hydrogen-containing polyether and / or organic polyamine of the present invention have excellent quality and can be used at a high rate to produce new polyurethane foams. Even if new polyurethane foams are produced using 100% of the active hydrogen-containing polyether of the present invention, high-quality polyurethane foams will be obtained. Without being bound by any theory, the inventors believe that the specific mild reaction conditions of the method of the present invention avoid the formation of by-products that can cause problems during polyurethane production. DETAILED DESCRIPTION OF THE INVENTION

[0015] Thus, one embodiment of the present invention is the process as defined in claim 1, the dependent claims and the specification. A further embodiment is the use of the recovered active hydrogen-containing polyether, preferably polyether polyol, and / or organic polyamine of the present invention for the production of polyurethanes, in particular polyurethane foams.

[0016] Before describing the present invention in more detail, some important terms are defined below. As used in this specification, examples, and claims, the verb "comprise" and its conjugations are used in an open-ended sense to mean that the items following the word are included, but items not specifically mentioned are not excluded. In its preferred embodiment, "comprising" includes "consisting of," which means that the items following the word "comprising" are included without additional items not specifically mentioned.

[0017] A reference to an element with the indefinite article "a" or "an" does not exclude the possibility that a plurality of elements are present, unless the context clearly requires that only one element is present. Thus, the indefinite article "a" or "an" normally means "one or more." The terms "catalyst" and "activator" are used interchangeably in this invention.

[0018] In the context of the present invention, polyurethane (PU) is specifically understood to mean a product obtained by reacting a polyisocyanate with a polyol or a compound having an isocyanate-reactive group. Polyurethanes that can be used in the process of the present invention are those prepared from active hydrogen-containing polyethers and polyisocyanates. This type of polyurethane is well known and is described, for example, in "Urethane Polymers" by Ulrich, Encyclopedia of Chemical Technology, Vol. 23, pp. 576-608 (1983), and "Polyurethanes" by Backus et al., Encyclopedia of Polymer Science and Technology, Vol. 13, pp. 243-303 (1988). Any known polyurethane can be used in the process of the present invention.

[0019] The active hydrogen-containing polyether is preferably a polyether polyol (i.e., a polyether having primary and / or secondary end groups, preferably hydroxyl groups), but may also be an amine-functionalized polyether (e.g., "Jeffamine" polyoxypropylamine sold by Texaco Chemical). Such materials are generally prepared by the catalyzed ring-opening polymerization of one or more cyclic ethers, such as epoxides, oxetanes, or oxolanes. Initiators containing two or more active hydrogens, such as polyhydric alcohols, amines, or acids, can be used to vary the functionality (number of active hydrogens) of the polyether. When two or more cyclic ethers are used, they can be reacted simultaneously (to obtain random copolymers) or sequentially (to obtain block copolymers). Exemplary cyclic ethers include propylene oxide, ethylene oxide, butylene oxide, tetrahydrofuran, and oxetane. Examples of suitable active hydrogen-containing polyethers include polypropylene glycol, polyethylene glycol, polytetramethylene glycol, polytrimethylene glycol, ethylene oxide-capped polypropylene glycol, and random copolymers of ethylene oxide and propylene oxide.

[0020] The structure of the active hydrogen-containing polyether, preferably polyether polyol, recovered by the process of the present invention correlates with the structure of the polyether polyol used to prepare the polyurethane treated by the process of the present invention. The structure of the polyamine recovered by the process of the present invention correlates with the structure of the polyisocyanate used to prepare the polyurethane treated by the process of the present invention. The term "polyamine" as used in the present invention includes diamines, and preferably includes amines having two or more primary amino groups in the molecule.

[0021] The polyurethanes used in the method of the present invention can be derived from any polyisocyanate reactant (i.e., organic compounds containing two or more isocyanate groups). Suitable polyisocyanates include, but are not limited to, aliphatic diisocyanates, cycloaliphatic diisocyanates, arylalkyl diisocyanates, aromatic diisocyanates (e.g., toluene diisocyanate and diisocyanatodiphenylmethane), aromatic triisocyanates, and isocyanate mixtures such as the isocyanate commonly referred to as "PMDI." Of course, modified, masked, or blocked polyisocyanates can also be utilized.

[0022] The polyurethanes used in the process of the present invention may contain any of the conventional additional reactants or additives known in the art, such as chain extenders or curing agents (relatively low molecular weight active hydrogen-containing compounds such as glycols and di- or polyamines), physical or chemical blowing agents, flame retardants, surfactants, fillers, stabilizers, antioxidants, colorants, polymers other than polyurethane polymers (e.g., styrene-acrylonitrile copolymers such as found in polymer polyols), catalysts, such as catalysts that promote gelation reactions (isocyanate-polyol), blowing reactions (isocyanate-water), and / or isocyanate dimerization or trimerization. Polyurethanes may be in solid, microcellular, or foam form and may range from rubbery, elastomeric, soft materials to rigid, hard materials.

[0023] To facilitate handling of the polyurethane, it is preferably desirable to chop, crush, grind, or otherwise comminute the polyurethane so that it is in the form of relatively small particles or granules. If the polyurethane is a foam, it may be partially or fully compressed before contacting with water, a strong base, and an activator. If the polyurethane is in solid form, an initial crushing step is highly advantageous to maximize the surface area available for reaction (thereby shortening the reaction time required to achieve the desired level of hydrolysis).

[0024] The process of the present invention provides for the efficient hydrolytic cleavage of urethane and urea linkages present in polyurethanes that are treated to produce active hydrogen-containing polyethers, preferably polyether polyols, polyamines, and, if the polyurethanes are prepared using chain extenders or curing agents, low molecular weight glycols, diols, and diamines.

[0025] The bases used in the present invention have a pK at 25°C of less than 1, preferably between 0.5 and -2, more preferably between 0.25 and -1.5, and most preferably between 0 and -1. b Inorganic bases are strong inorganic bases having a C—H bond.

[0026] Particularly preferred strong bases are selected from the group consisting of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides, and mixtures thereof. Preferred alkali metals are selected from the group consisting of Na, K, and Li, and mixtures thereof, most preferably Na and K, and mixtures thereof. Preferred alkaline earth metals are selected from the group consisting of Be, Mg, Ca, Sr, Ba, and mixtures thereof, most preferably Mg and Ca, and mixtures thereof. Most preferred alkali metals are selected from the group consisting of potassium or sodium, and mixtures thereof.

[0027] The use of the aforementioned bases allows the process of the present invention to be carried out at lower temperatures and with higher yields compared to prior art processes, thus contributing significantly to reduced operating costs.

[0028] The amount of base in the reaction mixture must be sufficient to catalyze the desired hydrolysis of the polyurethane at a practical rate. Preferably, the weight ratio of base to polyurethane is 0.01 to 25, more preferably 0.1 to 15, even more preferably 0.2 to 10, and most preferably 0.5 to 5. The base is preferably used in the form of a base solution containing base and water. For efficient conversion, it is particularly preferred if the concentration of base in the base solution is 5% by weight or more, preferably 5 to 70% by weight, more preferably 5 to 60% by weight, even more preferably 10 to 50% by weight, particularly preferably 15 to 40% by weight, and most preferably 20 to 40% by weight, based on the weight of the base solution.

[0029] Quaternary ammonium salts are used as phase transfer catalysts in the process of the present invention. Although the addition of even trace amounts of these catalysts accelerates the rate of hydrolysis, it is preferred to use at least 0.5 wt. % of catalyst, based on the weight of polyurethane, more preferably 0.5 to 15 wt. %, even more preferably 1 to 10 wt. %, particularly preferably 1 to 8 wt. %, especially preferably 1 to 7 wt. %, and most preferably 1 to 6 wt. %.

[0030] Quaternary ammonium salts useful in the present invention include organic nitrogen-containing compounds whose molecular structure comprises a central positively charged nitrogen atom, i.e., an ammonium cation, bonded to four organic (i.e., hydrocarbyl) groups, and a negatively charged anion such as a halide, preferably chloride, bromide, hydrogen sulfate, alkyl sulfate, preferably methyl sulfate and ethyl sulfate, carbonate, bicarbonate, carboxylate, preferably acetate, or hydroxide.

[0031] Quaternary ammonium salts are well known and are described, for example, in "Surfactants and Defense Systems" by Cahn et al., Encyclopedia of Chemical Technology, Third Edition, Vol. 22, pp. 383-385 (1983), and Catonic Surfactants, by E. Jungermann, edited by Marcel Dekker, New York (1970), pp. 1-173. Many such compounds are commercially available at relatively low cost.

[0032] Quaternary ammonium salts containing ammonium cations containing a total of 6 to 14 carbon atoms when the ammonium cation does not contain a benzyl residue, or 6 to 12 carbon atoms when the ammonium cation contains a benzyl residue, have been found to be most effective in the process of the present invention. In contrast to the teachings of U.S. Pat. No. 5,208,379, the present inventors have found that the yield decreases significantly when ammonium cations containing more carbon atoms are used at the same reaction temperature. The same is true for ammonium cations containing less than 6 carbon atoms.

[0033] Catalysts which have proven to be highly efficient and are therefore preferably used in the process of the present invention are quaternary ammonium salts having the general structure R1R2R3R4NX, where R1, R2, R3 and R4 are the same or different and are hydrocarbyl groups selected from alkyl, aryl and arylalkyl, and X is selected from the group consisting of halides, preferably chloride and / or bromide, hydrogen sulfate, alkyl sulfate, preferably methyl sulfate and ethyl sulfate, carbonate, hydrogen carbonate, carboxylate, preferably acetate, or hydroxide.

[0034] Preferably - R1 to R3 are the same or different and are alkyl groups having 1 to 6, preferably 1 to 5, more preferably 1 to 4, even more preferably 1 to 3, particularly preferably 1 or 2, and most preferably 1 carbon atom, which alkyl group may be linear, branched, cyclic, saturated, or unsaturated, and most preferably is a linear, saturated alkyl group; -R4 is selected from the group consisting of alkyl groups having 3 to 11, preferably 3 to 10, more preferably 3 to 8, and most preferably 4 to 6 carbon atoms, aryl groups having 6 to 11, preferably 6 to 10, and most preferably 6 to 8 carbon atoms, and aralkyl groups having 7 to 11, preferably 7 to 10, and most preferably 7 to 9 carbon atoms, wherein the alkyl groups may be linear, branched, cyclic, saturated, or unsaturated, and are most preferably linear saturated alkyl groups; and -X is selected from the group consisting of halides, preferably chloride and / or bromide, hydrogen sulfates, alkyl sulfates, preferably methyl sulfate and ethyl sulfate, carbonates, hydrogen carbonates, acetates or hydroxides.

[0035] In a first preferred embodiment, the catalyst is a quaternary ammonium salt having the general structure R1R2R3R4NX, where R4 is different from a benzyl residue, and R1-R4 are selected so that the total number of carbon atoms in the quaternary ammonium cation is 6 to 14, preferably 7 to 14, more preferably 8 to 13.

[0036] In a second preferred embodiment, the catalyst is a quaternary ammonium salt having the general structure R1R2R3R4NX, where R4 is a benzyl residue and R1-R3 are selected so that the total number of carbon atoms in the quaternary ammonium cation is 6 to 12, preferably 7 to 12, more preferably 8 to 11.

[0037] The most preferred quaternary ammonium salts suitable for use as activators in the method of the present invention include benzyltrimethylammonium chloride and tributylmethylammonium chloride.

[0038] Preferably, the polyurethane is reacted with water, base, and catalyst in the process of the present invention at a temperature of 80°C to 200°C, preferably 90°C to 180°C, more preferably 95°C to 170°C, and most preferably 100°C to 160°C. If the temperature is too low, the yield will be insufficient. If the temperature is too high, it will be economically inefficient and may cause side reactions that form undesirable by-products.

[0039] Preferably, the polyurethane is reacted with water, base and catalyst for 1 minute to 14 hours, preferably 1 minute to 12 hours, more preferably 5 minutes to 12 hours, even more preferably 10 minutes to 11 hours, particularly preferably 20 minutes to 10 hours, especially preferably 20 minutes to 8 hours, and most preferably 20 minutes to 7 hours.

[0040] Water functions as a reactant in the desired polyurethane hydrolysis reaction, and therefore need not be present in stoichiometric excess relative to the urethane functional groups in the polymer being hydrolyzed. However, it is generally desirable to utilize a significant amount of water so that it can conveniently function as a reaction medium and solvent or carrier for the strong base and activator. For these reasons, water is preferably present in condensed (liquid) form. Typically, the weight ratio of polyurethane to water is 3:1 to 1:15.

[0041] The hydrolysis is preferably carried out at atmospheric pressure, although superatmospheric pressure may be used if desired. A water-miscible or water-immiscible solvent, such as an alcohol, ketone, ester, ether, amide, sulfoxide, halogenated hydrocarbon, aliphatic hydrocarbon, or aromatic hydrocarbon, may be present in the reaction mixture to facilitate the hydrolysis process or to aid in recovery of the reaction product.

[0042] The hydrolysis reaction can be carried out batchwise, continuously, or semi-continuously in any suitable vessel or other apparatus (e.g., a stirred tank reactor or a screw extruder) whereby the polyurethane can be contacted with water in the presence of a base and an activator. Agitation or stirring of the reaction components is generally preferred to ensure intimate contact, a rapid rate of hydrolysis, and adequate temperature control.

[0043] The active hydrogen-containing polyether, preferably polyether polyol, organic polyamine, chain extender, and curing agent produced by hydrolysis can be separated and recovered from the crude reaction mixture using any suitable method or combination of methods known in the art, such as, for example, extraction (e.g., using a water-immiscible organic solvent as the extractant), distillation, precipitation, filtration, etc.

[0044] The recovered active hydrogen-containing polyethers, preferably polyether polyols, obtained by the process of the present invention are of superior quality, and the inventors have found that they can be used to produce high-quality polyurethane foams without the addition of virgin polyether polyol, which is a significant improvement over prior art polyurethane depolymerization processes.

[0045] The recovered polyamines can be converted to organic polyisocyanates by conventional methods and similarly used as components of polyurethanes.

[0046] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following examples, therefore, should be construed as merely illustrative, and not limitative of the claims or the remainder of the disclosure in any way whatsoever. [Example]

[0047] (Examples 1 to 5 and Comparative Examples CE1 to CE6)

[0048] A Parr Instrumental reactor equipped with a PTFE liner and mechanical stirrer was charged with 25 g of compressed polyurethane foam pieces (approximately 1 cm x 1 cm) and 75 g of aqueous base was added. The catalyst was then added, the reactor was closed, and the mixture was heated to operating temperature. After the desired reaction time, the mixture was cooled, the reactor was opened, and the reaction mixture was transferred to a round-bottom flask.

[0049] The water was removed and the remaining solid was extracted with cyclohexane. The cyclohexane solution was washed with 1N aqueous HCl, dried over magnesium sulfate, and the solvent was removed. The solid was extracted with warm toluene to give the amine after drying and solvent removal.

[0050] Table 1 shows the base solution and catalyst used, their amounts, reaction time and temperature, and the yields of recovered polyether polyol and amine.

[0051] [Table 1] TBMAC = tributylmethylammonium chloride (C=13) BnTMAC = benzyltrimethylammonium chloride (C=10) TBAHS = tetrabutylammonium hydrogen sulfate (C=16) Variquat K 1215 = Methylbis(polyethoxyethanol)cocoammonium chloride (C>37) Varisoft 137-90 = Dimethyldi(C 14 -C 18 Alkyl)ammonium methyl sulfate (C>30) Adogen 432 CG = Dihexadecyldimethylammonium chloride (C=34)

[0052] All Comparative Examples CE1-6 meet the requirements of U.S. Pat. No. 5,208,379, i.e., the number of ammonium cations or carbon atoms is greater than 15. In contrast, in Examples 1 to 5 of the present invention, the number of carbon atoms in the ammonium cation is 13 and 10, respectively, i.e., less than 15, and therefore outside the scope of U.S. Pat. No. 5,208,379. The Examples and Comparative Examples demonstrate that under all reaction conditions, the process of the present invention provides better yields than the process of U.S. Pat. No. 5,208,379.

[0053] Performance Test Manufacturing of thermosetting flexible PU foam (flexible slabstock foam)

[0054] For performance testing of recycled polyols, the thermoset flexible PU foam formulations specified in Table 2 were used.

[0055] [Table 2] 1) Polyol 1: Arcol® 1104 standard virgin polyol available from Covestro, a glycerol-based polyether polyol with an OH number of 56 mg KOH / g and an average molar mass of 3000 g / mol, or a recycled polyol of the present invention or a recycled polyol not of the present invention. The recycled polyol is obtained by chemical regeneration from flexible polyurethane foam. The recycled polyol of the present invention from Example 2 was used. 2) KOSMOS® T9, available from Evonik Industries: tin(II) salt of 2-ethylhexanoic acid. 3) DABCO® DMEA: Dimethylethanolamine, available from Evonik Industries. An amine catalyst for producing polyurethane foams. 4) Polyether modified polysiloxane, available from Evonik Industries. 5)Tolylene diisocyanate T 80 (80% 2,4 isomer, 20% 2,6 isomer), from Covestro, 3 mPa s, 48% NCO, functionality 2. 6) KOSMOS® EF, an emission-free metal catalyst, available from Evonik Industries: tin(II) salt of ricinoleic acid 7) DABCO® NE 1050: A low-emissions amine catalyst, available from Evonik Industries. 8) A low-emitting polyether-modified polysiloxane with less than 0.03% by weight of total cyclic siloxanes available from Evonik Industries.

[0056] Recycled polyol production Recycled Polyol 1 (not of the present invention)

[0057] Recycled polyol 1, which is not the present invention, was produced according to the procedure published by H&S Anlagentechnik in 2012: https: / / www.dbu.de / OPAC / ab / DBU-Abschlussbericht-AZ-29395.pdf

[0058] A Parr Instrumental reactor equipped with a glass in liner and a mechanical stirrer was charged with 300.2 g of compressed polyurethane foam pieces (approximately 1 cm x 1 cm). The polyurethane foam used was made according to Formulation 1, Table 2, using conventional polyol Arcol® 1104.

[0059] 152.64 g of polyol Arcol® 1104, 75.63 g of phthalic acid, and 11.97 g of hydrogen peroxide (30 wt % in water) were added to the foam pieces. The reaction mixture was heated to an internal temperature of 250°C. Under these conditions, the reaction was maintained at an internal temperature of 237°C-256°C for 5 hours. After heating was stopped, a second portion of 140.63 g of Arcol® 1104 was added at 160°C under a nitrogen atmosphere. At 80°C, the reaction mixture was decanted and then cooled to room temperature. The cooled, decanted reaction mixture was used as non-inventive recycled polyol 1. This process was repeated to produce a sufficient amount of recycled polyol for foaming experiments.

[0060] Recycled Polyol 2 (Invention)

[0061] The recycled polyol of the present invention from Example 2 was used.

[0062] General procedure for preparing foam samples

[0063] For each foaming test, 300 g of polyol was used. Other formulation ingredients were recalculated accordingly. For example, 1.00 parts of a given ingredient was calculated for 1.00 g of this material per 100 g of polyol.

[0064] Foaming was performed using a so-called manual mixing process. Formulation 1 or Formulation 2, listed in Table 2, was used. To this end, a paper cup was charged with the different polyols, their respective amine catalysts, the tin catalyst tin(II) 2-ethylhexanoate, water, and foam stabilizer. The contents were mixed with a disc stirrer at 1000 rpm for 60 seconds. After the initial stirring, the isocyanate (TDI) was added to the reaction mixture, which was then stirred at 2500 rpm for 7 seconds. The reaction mixture was then immediately transferred to a paper-lined box (30 cm x 30 cm base area and 30 cm height). After injection, the foam rose within the box. Ideally, the foam would blow up once it reached its maximum rise height and then drop slightly. This opened the foam's cell membrane, resulting in an open-cell structure. Defined foams were cut from the resulting thermoset soft PU foam block for further analysis.

[0065] Characterization of soft PU foam: The produced flexible polyurethane foams were evaluated according to the following foam properties a) to l): a) Falling of the foam after the end of the rising phase (=settling): The difference in foam height after direct blow-off and 3 minutes after foam blow-off indicates a settling or further rising. The foam height is measured at its maximum in the center of the foam peak with a needle fixed to a centimeter scale. Positive values ​​here represent a settling of the foam after blow-off. Negative values ​​represent a corresponding further rise of the foam. b) Foam Height: The height of the freely rising foam formed after 3 minutes. Foam height is reported in centimeters (cm). c) Rise Time: The time between the end of mixing of the reactants and the blow-off of the polyurethane foam. Rise time is reported in seconds (s). d) Porosity by Dynamic Pressure Measurement: The gas permeability of foams was determined by dynamic pressure measurement of the foams according to DIN EN ISO 4638:1993-07. The measured dynamic pressure is reported in mm of water column, with lower dynamic pressure values ​​characterizing more open foams. Values ​​were measured in the range of 0 to 300 mm of water column. The dynamic pressure was measured using an apparatus including a nitrogen source, a pressure reducing valve with a pressure gauge, a flow adjustment screw, a wash bottle, a flow meter, a T-piece, an applicator nozzle, and a graduated glass tube filled with water. The applicator nozzle had an edge length of 100 x 100 mm, a weight of 800 g, an inner diameter of the outlet opening of 5 mm, an inner diameter of the lower applicator ring of 20 mm, and an outer diameter of the lower applicator ring of 30 mm. The measurement was performed by setting the nitrogen inlet pressure to 1 bar via the pressure reducing valve and the flow rate to 480 l / h. The volume of water in the graduated glass tube was adjusted so that no pressure difference occurred and no readout was possible. For measurements on specimens with dimensions of 250 x 250 x 50 mm, the applicator nozzle is placed once at the corner of the specimen, flush with the edge, and once at the (presumed) center of the specimen (in each case the side with the largest surface area). The result is read out when a constant dynamic pressure has been established. The final result is calculated by forming the average of the five measurements obtained. e) Number of bubbles per cm (bubble count): This is determined visually on a cut surface (measured in accordance with DIN EN 15702). f) Compression hardness CLD, 40% to DIN EN ISO 33861:1997+A1:2010. Measurements are reported in kilopascals (kPa). g) Constant Deflection Compression Set (commonly called compression set) Five test specimens measuring 5 cm x 5 cm x 2.5 cm were cut from the finished foam. The initial thickness was measured. The compression set was measured 72 hours after production according to DIN EN ISO 1856 2018. The specimens were placed between the plates of a deformation apparatus and compressed by 90% of their thickness (i.e., to 2.5 mm). Within 15 minutes, the specimens were placed in a 70°C oven and left there for 22 hours. After this, the apparatus was removed from the oven, and the specimens were removed from the apparatus within 1 minute and placed on a wooden surface. After 30 minutes of relaxation, the thickness was measured again, and the compression set was calculated. The results are reported as a percentage of the original thickness: DVR = (d0 - dr) / d0 x 100%. h) Tensile strength and elongation at break in accordance with DIN EN ISO 1798:2008. Tensile strength measurements are reported in kilopascals (kPa) and elongation at break measurements are reported in percent (%). i) Resilience according to DIN EN ISO 8307:2007. Measurements are reported in percent (%). j) Emission profile at room temperature according to DIN EN ISO 16000-9:2008-04. Materials are characterized here with regard to the type and amount of organic substances emitted by them. Analytical methods are useful for determining emissions from materials used in furniture and mattresses. This is done by measuring emissions at room temperature using a test chamber. analysis Test Specimens: Sample Preparation, Sampling, and Specimen Dimensions The reaction mixture was transferred to a box (30 cm x 30 cm base area and 30 cm height) covered with an open-top PE plastic bag. After injection, the foam was allowed to rise within the foam box. Ideally, the foam was blown up once it reached its maximum height and then allowed to drop slightly. This opened the foam's bubble membrane, resulting in an open-cell structure. After the foam had risen and been blown up, the PE bag was closed 3 minutes after blowing. The foam was stored in this manner at room temperature for 12 hours to allow for complete reaction, while at the same time preventing premature leakage of VOCs. The PE bag was then opened, and a 7 cm x 7 cm x 7 cm cube was removed from the center of the foam block. This was immediately wrapped in aluminum foil and airtightly sealed in the PE bag. This was then transported to the analytical laboratory, where the foam cube was introduced into a cleaned 30 L glass test chamber. Conditions within the test chamber were controlled climatically (21°C temperature, 50% humidity). Half of the test chamber's volume was replaced every hour. After 24 hours, samples are taken from the test chamber air. Tenax adsorption tubes serve to adsorb the VOCs. The Tenax tubes are then heated, and the released volatile substances are cryofocused in the cold trap of a temperature-programmable evaporator with the aid of an inert gas flow. After the heating phase and cryofocusing are complete, the cold trap is rapidly heated to 280°C, evaporating the focused substances. They are then separated in a gas chromatography separation column and detected by mass spectrometry. Calibration with reference substances allows the determination of "µg / m 3This allows for a semi-quantitative estimation of emissions, expressed as "." The quantitative reference substance (VOC value) used for VOC analysis is toluene. Signal peaks can be assigned to substances using their mass spectra and retention indices. The following equipment is used for the analysis: Gerstel, D-45473 Muhlheim an der Ruhr, Eberhard-Gerstel-Platz 1, Germany, TDS-3 / KAS-4, Tenax® desorption tube, Agilent Technologies 7890A (GC) / 5975C (MS), column: HP Ultra2 (50 m, 0.32 mm, 0.52 μm), carrier gas: helium. A more specific description of the procedure can be found in DIN EN ISO 16000-9:2008-04. k) Odor test of the resulting foams. The finished foams were packed in odor-neutral plastic bags and stored under airtight conditions. For odor evaluation of the foams, cubes measuring 10 cm x 10 cm x 10 cm were cut out and transferred to 1 L bottles from which the samples were sniffed. The bottles were closed with screw caps. The odor test was performed after storing the bottles at 22°C for 24 hours. The odor test was evaluated by a panel of 13 trained odor testers. They were asked to rate the odor intensity, with a low odor level being rated as +, a medium odor as ++, and a high odor as +++. l) Aldehyde emissions according to VDA 275 In this method, a test specimen of a specific mass and size is placed over distilled water in a sealed 1 L glass bottle and stored at a constant temperature for a specific period of time. The bottle is then cooled, and the absorbed aldehyde is measured in distilled water. The amount of aldehyde measured is based on the dry weight (mg / kg) of the foam sample. After removing the foam from the foam box, it is stored at 21°C and approximately 50% relative humidity for 24 hours. Then, samples of the foam block are taken at appropriate and representative locations evenly distributed across the width of the (cooled) foam block. The foam samples are then wrapped in aluminum foil and sealed in polyethylene bags. Each sample has a size of 100 x 40 x 40 mm thick (approximately 9 g). For each foam block, three test specimens are taken for aldehyde measurement. The sealed samples are sent for measurement immediately after receipt. Before analysis, the samples are weighed to an accuracy of 0.001 g on an analytical balance. 50 ml of distilled water is pipetted into each used vial. The samples are placed in the vials, the containers are sealed, and kept at a constant temperature of 60 °C in a thermal cabinet for 3 hours. After the test period, the containers are removed from the thermal cabinet. After leaving them at room temperature for 60 minutes, the samples are removed from the test vials. This is followed by derivatization using the DNPH method (dinitrophenylhydrazine). For this, 900 μl of the aqueous phase is mixed with 100 μl of DNPH solution. The DNPH solution is prepared as follows: 50 mg of DNPH in 40 ml of MeCN (acetonitrile) is acidified with 250 μl of dilute HCl (1:10) and made up to 50 ml with MeCN. Once derivatization is complete, the samples are analyzed by HPLC. Separation into individual aldehyde homologs is performed. HPLC instrument parameters The following equipment is used for the analysis: Agilent Technologies 1260 Chromatography column: Phenomenex Luna 250*4.6mm C18, particle size 5μ Eluent: Water-acetonitrile gradient Detection: UV 365nm

[0066] Results of the foaming experiment The results of the influence of recycled polyols according to the present invention on the foaming process and foam physical properties of the resulting thermoset flexible PU foams are summarized in the following table: Thermoset flexible PU foams were produced according to Formulation 1, Table 2, using standard virgin polyol, recycled polyols not according to the present invention, and recycled polyol 2 according to the present invention.

[0067] [Table 3]

[0068] The foaming results in Table 3 demonstrate that by replacing standard virgin Arcol® 1104 polyol with recycled Polyol 2 of the present invention (Foam #8), flexible PU foams can be produced with foam processing properties comparable to the benchmark foam (#6). Furthermore, the physical properties of all foams are comparable to the benchmark foam. In contrast, 100 pphp of recycled Polyol 1, not of the present invention, was not able to produce a reasonable foam; the foam collapsed (Foam #7).

[0069] The results of the effect of recycled polyols according to the invention on foam emissions at room temperature are summarized in Table 4. Thermoset flexible PU foams were produced according to Formulation 2, Table 2, by using standard virgin polyol, recycled polyol 1 (not according to the invention) and recycled polyol 2 according to the invention.

[0070] [Table 4]

[0071] The thermoset flexible PU foams according to the invention are found to have low emissions when emission-optimized additives are used. This can be seen in the VOC test according to DIN EN ISO 16000-9:2008-04. When 100 pphp of the inventive recycled polyol 2 is used, the total emissions increase slightly (50 μg / m for Foam #9). 3 to 125 μg / m of foam #11 3(up to 500μg / m), emissions are still below 500μg / m 3 This is well below the typical TVOC limit. Thus, recycled Polyol 2 of the present invention is suitable for low-emission formulations. In contrast, it was not possible to produce a reasonable foam using 100 pphp of recycled Polyol 1, which is not of the present invention.

[0072] The results in Table 4 show that flexible PU foams with comparable odor characteristics and aldehyde emissions can be produced by replacing the standard virgin polyol Arcol® 1104 with recycled polyol 2 of the present invention. The formaldehyde, acetaldehyde, and propionaldehyde emissions measured by VDA 275 are in comparable ranges for Foam #9 and Foam #11.

Claims

1. 1. A method for hydrolyzing polyurethane, comprising hydrolyzing said polyurethane to a pK of less than 1 at 25°C. ｂ and a quaternary ammonium salt containing an ammonium cation containing 6 to 14 carbon atoms if the ammonium cation does not contain a benzyl residue, or 6 to 12 carbon atoms if the ammonium cation contains a benzyl residue, as a catalyst, to obtain an active hydrogen-containing polyether and an organic polyamine.

2. 10. The method of claim 1, wherein the strong base is selected from the group consisting of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides, and mixtures thereof.

3. 3. The method of claim 2, wherein the alkali metal is selected from the group consisting of Na, K, and Li and mixtures thereof, and / or the alkaline earth metal is selected from the group consisting of Be, Mg, Ca, Sr, Ba, and mixtures thereof.

4. The catalyst has the general structure R １ R ２ R ３ R ４ NX, wherein R １ , R ２ , R ３ , and R ４ 10. The method of claim 1, wherein X is the same or different and is a hydrocarbyl group selected from alkyl, aryl, and arylalkyl; and X is selected from the group consisting of halide, hydrogen sulfate, alkyl sulfate, carbonate, bicarbonate, carboxylate, or hydroxide.

5. R １ ~R ３ are the same or different alkyl groups having 1 to 6 carbon atoms, said alkyl groups may be linear, branched, cyclic, saturated or unsaturated; R ４ is selected from the group consisting of alkyl groups having 3 to 11 carbon atoms, aryl groups having 6 to 11 carbon atoms, and aralkyl groups having 7 to 11 carbon atoms, wherein the alkyl groups may be linear, branched, cyclic, saturated, or unsaturated; and X is selected from the group consisting of halide, hydrogen sulfate, alkyl sulfate, carbonate, bicarbonate, acetate or hydroxide; The method of claim 4.

6. R ４ is different from the benzyl residue, R １ ~R ４ is selected so that the total number of carbon atoms in the quaternary ammonium cation is 6 to 14.

7. R ４ is a benzyl residue, and R １ ~R ３ is selected so that the total number of carbon atoms in the quaternary ammonium cation is 6 to 12.

8. 10. The method of claim 1, including the additional step of separating and recovering the organic polyamine and / or active hydrogen-containing polyether.

9. The method of claim 1 , wherein the polyurethane is foamed.

10. said polyurethane with water, said base and said catalyst; At temperatures between 80℃ and 200℃ and / or 1 minute to 14 hours and / or 2. The process of claim 1, wherein the reaction is carried out at atmospheric pressure.

11. The method of claim 1 wherein at least 0.5 weight percent of the catalyst is used based on the weight of the polyurethane.

12. 10. The method of claim 1, wherein the weight ratio of the base to polyurethane is from 0.01 to 25.

13. 2. The method of claim 1, wherein a base solution containing a base and water is used, and the concentration of the base is 5% by weight or more, based on the weight of the base solution.

14. 10. Use of an active hydrogen-containing polyether and / or organic polyamine obtained by the process of claim 1 for the production of polyurethanes.

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