Alkali depolymerization of polyisocyanurate with organic amine

Abstract

The invention relates to a method for depolymerizing polyisocyanurate, in particular soft and hard polyisocyanurate foams, in a reaction mixture under mild conditions and at low salt concentrations, in which valuable raw materials of polyisocyanurate can be recovered in high yields and good quality, the recycled raw materials are recycled, i.e., the quality allows the recycled raw materials to be used for producing new polyurethanes, preferably polyurethane foams, or polyisocyanurate, preferably polyisocyanurate foams.

Description

[0001] The present invention relates to a process for depolymerizing polyisocyanurates, especially rigid polyisocyanurate foams, in a reaction mixture under mild conditions and at low salt concentrations, wherein valuable starting materials of the polyisocyanurates can be recovered in high yields and good quality, i.e., the quality allows the use of the recovered starting materials for the production of new chemicals, especially new polyurethanes, preferably polyurethane foams, or polyisocyanurates, preferably polyisocyanurate foams.

[0002] Polyurethanes are materials of considerable utility in the production of rigid and flexible foams, solid and microcellular elastomers, sealants, coatings, and adhesives. The versatility, relatively low cost, and excellent properties of polyurethanes have led to the rapid growth of the polyurethane industry over the past 50 years. Currently, thousands of tons of polyurethanes are produced worldwide each year, and different methods have been developed for the chemical recycling of polyurethanes, such as glycolysis, ammonolysis, aminolysis, acidolysis, and hydrolysis. The common feature of these methods is that mainly the urethane and urea groups are cleaved, but adjacent allophanate, carbodiimide, urethane, and biuret groups are also cleaved.

[0003] Polyisocyanurate polymers differ from polyurethanes in that they contain isocyanurate groups, which, due to the ring structure of the isocyanurate groups, are more stable and less reactive than the functional groups cleaved during the chemical decomposition of polyurethanes. Another difference between polyurethanes and polyisocyanurates is that polyurethanes are typically formed by the reaction of polyisocyanates and polyether polyols, while polyisocyanurates are obtained by the reaction of polyisocyanates and polyester polyols. In contrast to polyether groups, polyester groups are also cleaved during chemical decomposition. Therefore, the chemical methods developed and used for the recycling of polyurethanes cannot be applied to polyisocyanurates.

[0004] Due to their higher chemical stability, polyisocyanurate foams are used as insulating panels in applications with particularly high requirements for strength and flame retardancy. It has long been known to those skilled in the art that the high chemical stability of polyisocyanurates can be achieved by a large number of isocyanurate groups. The general view in the art is that polyisocyanurate foams cannot be split in a recycling process based on chemical recycling, especially hydrolysis, to recover the starting materials of the polyisocyanurate foams, and the isocyanurate structure is mostly retained.

[0005] P.N. Gribkova et al., "Degradation of a polyisocyanurate obtained by polycyclotrimerization of 4,4'-di-isocyanatodiphenylmethan", Polymer Science U.S.S.R., Vol. 22, pp. 299 - 304 compared the thermal degradation, hydrolysis degradation and thermo-oxidative degradation of isocyanurates. It was found that homolytic decomposition and formation of CO and H2 were observed under all conditions and no high yields of starting materials were obtained. This confirmed the general view in the art that polyisocyanurates cannot be recycled as monomers that can be reused for the production of new polyisocyanurates or polyurethanes.

[0006] Due to the high chemical stability of polyisocyanurates, the development of chemical recycling methods has so far focused on polyurethane foams containing polyether polyols and with an isocyanate index below 150.

[0007] Resource scarcity, climate change, environmental impacts and increased awareness of sustainable products have led to an increased demand for new technologies for recycling plastics. Due to their large presence in the market, this applies to polyurethanes as well as to polyisocyanurates.

[0008] Therefore, there is a strong need to provide effective and sustainable methods for recycling polyisocyanurates, thereby recovering valuable starting materials in good yields and good quality, i.e., of a quality that allows them to be preferably reused as starting materials for new polyurethanes and polyisocyanurates.

[0009] Therefore, the object of the present invention is to provide a new method for depolymerizing polyisocyanurates, as well as a method for separating and recovering the recovered hydrolysis products preferably for reuse in the production of chemicals. In particular, an object of the present invention is to provide a new method for depolymerizing polyisocyanurates in which ring rupture of the polyisocyanurate and cleavage of the urethane bond occur.

[0010] A particular subject of the present invention is to provide a method that can be carried out in standard equipment, namely a steel reactor.

[0011] Another specific problem of the present invention is to provide a method that can operate at a good yield at a lower temperature.

[0012] Another specific subject of the present invention is to provide a method that allows easy separation of the hydrolysis reactants and the catalyst from the recovered starting materials. The separation should be possible under mild conditions.

[0013] Another specific subject of the present invention is to provide a method with good yield and few side reactions. The method of the present invention should allow the splitting of more than 85%, preferably more than 90%, particularly preferably more than 95%, and even more preferably 100% of the isocyanurate groups present in the raw material. In this case, the splitting of the isocyanurate group means the first bond breakage of the isocyanurate group and ring opening occurs.

[0014] The method of the present invention should be applicable to polyisocyanurates with a high isocyanate index, which is preferably greater than or equal to 150, preferably > 150, more preferably > 250.

[0015] Another specific problem to be solved by the present invention is to provide a method that allows the recovery of polyols and / or amines and / or polyamines in a quality very close to that of the raw materials used for producing hydrolyzable polyisocyanurates. It should be possible to use the recovered polyols and / or amines and / or polyamines in a high proportion to produce new chemicals, preferably isocyanates, polyurethanes, polyisocyanurates or polyureas, or reuse them in other applications, such as as epoxy curing agents or as crosslinking agents for other polymers.

[0016] Another specific subject of the present invention is to provide a method that is beneficial in terms of sustainability compared to the prior art, particularly in reducing or avoiding inorganic salt waste.

[0017] Other problems solved by the present invention but not previously described can be derived from the following description, examples and claims.

[0018] The inventors have surprisingly discovered a method for hydrolyzing polyisocyanurates,

[0019] wherein

[0020] the polyisocyanurate is produced by reacting one or more polyols selected from polyester polyols, mixtures of polyester polyols, and mixtures of polyester polyols and polyether polyols with an excess of one or more isocyanates selected from organic isocyanates, mixtures of organic isocyanates, organic polyisocyanates, mixtures of organic polyisocyanates, and mixtures of organic isocyanates and organic polyisocyanates,

[0021] and wherein

[0022] the polyisocyanurate is contacted with water in the presence of an organic amine base to produce:

[0023] one or more carboxylic acids containing equal to or greater than 2 carboxylic acid groups per molecule, corresponding to the carboxylic acids used for preparing the polyester polyol used for preparing the polyisocyanurate,

[0024] and

[0025] One or more polyols corresponding to the polyols used for the preparation of polyester polyols, which polyester polyols are used for the preparation of polyisocyanurates,

[0026] and

[0027] one or more organic amines and / or polyamines corresponding to the organic isocyanates or polyisocyanates used for the preparation of polyisocyanurates,

[0028] and wherein

[0029] the reaction mixture comprising polyisocyanurate, water and an organic amine base is a stirred homogeneous or heterogeneous mixture during hydrolysis, preferably a solution or an emulsion or a dispersion or a combination thereof,

[0030] allowing the recovery of the raw materials for the preparation of polyisocyanurates, namely carboxylic acids and / or polyols and / or organic amines and / or organic polyamines, in high yield and purity.

[0031] Based on the initial amount of isocyanurate groups present in the raw materials, the process of the invention provides a particularly high cleavage rate of the isocyanurate groups present of greater than 85%, preferably greater than 90%, particularly preferably greater than 95%, and even more preferably 100%. The percentage of the cleavage rate can be determined by the disappearance of the signal at about 150 ppm measured in 13 13C NMR using TMS as a standard.

[0032] In addition to the ring rupture of the isocyanurate groups present, the process of the invention causes the polyester polyols used for the preparation of polyisocyanurates to split into their raw materials, i.e., the corresponding carboxylic acids and polyols can be recovered. These reaction products can be easily separated from the resulting amines formed as other reaction products. Thus, the recovered raw materials can be obtained in high purity.

[0033] The recovered amine component of the isocyanurate, preferably the aromatic amine component, can be recovered, for example, in a purity that allows phosgenation to polyisocyanates. The polyols and carboxylic acids are obtained in a purity that allows reuse in the production of polyurethanes or polyisocyanurates or for other applications such as polyesters. In particular, microcellular, uniform and low-interference foams can be produced from the recovered products, where these foams meet all market requirements in terms of, for example, density, strength, insulation properties or emissions. Advantageously, the recovered products of the invention can be used for the preparation of new polyurethane or polyisocyanurate foams without adversely affecting the properties of the foams.

[0034] The process of the invention is particularly advantageous because it allows the recovery of polyester polyol-based polyisocyanurate foams having a high isocyanate index of greater than or equal to 150, preferably > 150, more preferably > 250, which was not possible before.

[0035] In the process of the present invention, various organic amine bases can be used to effectively depolymerize polyisocyanurates, and these organic amine bases can be easily separated from the reaction products, namely carboxylic acids, polyols and polyamine components, preferably by distillation or extraction.

[0036] The organic amine bases used in the present invention are non-ionic organic bases, that is, not in the form of salts. Therefore, the amount of salts that need to be separated and treated in the reaction solution is low.

[0037] The inventors have surprisingly found that the organic amine bases used in the present invention can be used without adding a phase transfer catalyst. This reduces the salt load of the reaction mixture and thus reduces the work of separating and recovering the reaction products. Since the amount of salts that must be treated is lower, it also provides ecological and economic benefits.

[0038] Although the process of the present invention can be carried out without a phase transfer catalyst, the use of a phase transfer catalyst has been shown to accelerate the process compared to processes without a phase transfer catalyst in some systems. The phase transfer catalyst that can be added to the reaction mixture during hydrolysis is preferably selected from quaternary ammonium salts containing 6 to 30 carbon atoms and organic sulfonates containing at least 7 carbon atoms. Most preferably, it is a quaternary ammonium salt containing 6 to 30 carbon atoms.

[0039] Depending on preferences, lower salt load or shorter reaction time, the process of the present invention is very flexible. The inventors have found that if a phase transfer catalyst is used, ammonium cations are preferably used. Ammonium cations with a low number of carbon atoms (i.e., less than 15) as well as ammonium cations with a higher number of carbon atoms (i.e., 15 to 30) can be used effectively. The use of such phase transfer catalysts allows an increase in yield and an increase in flexibility with respect to the reaction temperature.

[0040] The organic amine bases used in the present invention are non-corrosive, so the process of the present invention can be carried out in standard equipment under low-corrosive or non-corrosive conditions.

[0041] Other benefits will be apparent from the following description, examples, claims and drawings.

[0042] Detailed description

[0043] Before describing the present invention in more detail, some important term definitions are as follows:

[0044] The verb "comprising" and its variations used in the specification, examples and claims are used in their non-limiting sense, meaning including the items following the word, but not excluding items not specifically mentioned. "Comprising" includes "consisting of", meaning including the items following the word "comprising" without any additional items not specifically mentioned as a preferred embodiment.

[0045] References to an element as the indefinite article "a" or "an" do not exclude the possibility of there being more than one element, unless the context clearly requires there to be one and only one element. Thus, the indefinite article "a" or "an" generally refers to "one or more".

[0046] The terms "catalyst" and "activator" are used synonymously in the present invention.

[0047] In the context of the present invention, polyurethane (PU) should in particular be understood to mean a product obtainable by the reaction of a polyisocyanate and a polyol or a compound having an isocyanate-reactive group. Polyurethanes can be prepared from polyethers containing active hydrogen and polyisocyanates. This type of polyurethane is well known and is described, for example, in Ulrich, "Urethane Polymers", Encyclopedia of Chemical Technology, Volume 23, pages 576 - 608 (1983) and Backus et al., "Polyurethanes", Encyclopedia of Polymer Science and Technology, Volume 13, pages 243 - 303 (1988).

[0048] In the context of the present invention, polyisocyanurate (PIR) should be understood to mean a product obtainable by the reaction of a polyol component with an excess of a polyisocyanate component, wherein the polyol component comprises a polyester polyol or a mixture of a polyester polyol and a polyether polyol. Preferably, the isocyanate index of the PIR is 150 or greater. During the reaction of the polyol component with the excess polyisocyanate component, a urethane structure is formed due to the reaction of the isocyanate with a compound having a reactive hydrogen atom in the polyol component, and an isocyanurate structure or other structures resulting from the reaction of isocyanate groups with each other or from the reaction of isocyanate groups with other groups such as urethane groups are formed. Polyisocyanurates have also been known and are described in the prior art.

[0049] The isocyanate index used in the present invention should be understood as the molar ratio of the polyisocyanate component to the polyol component multiplied by 100, or in other words, the molar ratio of the isocyanate groups to the isocyanate-reactive groups multiplied by 100.

[0050] Preferably, rigid PIR foams are used in the present invention. "Rigid foam" is a fixed technical term. The well-known and fundamental difference between flexible foam and rigid foam is that flexible foam shows elastic behavior and thus deformation is reversible. On the other hand, rigid foam is permanently deformed. Further information on rigid foam can also be found in "Kunststoffhandbuch, Band 7, Polyurethane", Carl Hanser Verlag, 3rd edition 1993, chapter 6. The terms "hard foam" or "rigid foam" are treated synonymously in the context of the present invention.

[0051] The method of the present invention is a method for hydrolyzing polyisocyanurate, characterized in that

[0052] the polyisocyanurate is produced by reacting one or more polyols selected from polyester polyols, mixtures of polyester polyols, and mixtures of polyester polyols and polyether polyols with an excess of one or more isocyanates selected from organic isocyanates, mixtures of organic isocyanates, organic polyisocyanates, mixtures of organic polyisocyanates, and mixtures of organic isocyanates and organic polyisocyanates,

[0053] and characterized in that

[0054] the polyisocyanurate is contacted with water in the presence of an organic amine base to produce:

[0055] one or more carboxylic acids each containing equal to or greater than 2 carboxylic acid groups per molecule, corresponding to the carboxylic acids used to prepare the polyester polyol used to prepare the polyisocyanurate,

[0056] and

[0057] one or more polyols corresponding to the polyols used to prepare the polyester polyol used to prepare the polyisocyanurate,

[0058] and

[0059] one or more organic amines and / or polyamines corresponding to the organic isocyanate or polyisocyanate used to prepare the polyisocyanurate,

[0060] and characterized in that

[0061] the reaction mixture containing polyisocyanurate, water, and organic amine base is a stirred homogeneous or heterogeneous mixture during hydrolysis, preferably a solution or emulsion or dispersion or a combination thereof.

[0062] The preferred PIR, more preferably PIR foam, and even more preferably rigid PIR foam used in the method of the present invention are produced by reacting

[0063] a) one or more polyols selected from polyester polyols or mixtures of polyester polyols or mixtures of polyester polyols and polyether polyols, and containing isocyanate-reactive groups selected from OH groups, SH groups, NH groups, NH2 groups, and mixtures thereof, preferably OH groups, with

[0064] b) an excess of one or more isocyanates selected from organic isocyanates, mixtures of organic isocyanates, organic polyisocyanates, mixtures of organic polyisocyanates, and mixtures of organic isocyanates and organic polyisocyanates,

[0065] in the presence of

[0066] c) a catalyst that catalyzes the reaction of the isocyanate-reactive groups with the isocyanate groups and / or the reaction of the isocyanate groups with each other, provided that it contains at least one trimerization catalyst

[0067] d) optionally, a foam stabilizer

[0068] e) optionally, a propellant

[0069] f) optionally, other additives

[0070] to produce.

[0071] Preferably, at least one polyol contains 2 or more isocyanate-reactive groups selected from OH groups, SH groups, NH groups, NH2 groups, and mixtures thereof, preferably OH groups. The more preferred polyol or mixture of polyols used in step a) has a total of on average 1.8 to 8, preferably 1.9 to 5, more preferably 2 to 3, and most preferably 2 of said isocyanate-reactive groups and on average 2 to 12, preferably 2 to 10, more preferably 2 to 6 carbon atoms. For example, a non-integer functionality of 1.8 can result from the fact that at least one polyol with a higher functionality, such as greater than or equal to 2, is mixed with at least one polyol with a functionality of 1, for example.

[0072] The polyol may contain ether and / or carbonate functional groups, preferably polyether polyols or polyethercarbonatpolyols.

[0073] Preferably, in step a), a polyester polyol based on esters of polyaliphatic or aromatic carboxylic acids or mixtures of aromatic and aliphatic carboxylic acids is used, wherein the carboxylic acid has 2 or 3, more preferably 2 carboxylic acid groups per molecule and has 2 to 12, preferably 4 to 10, more preferably 6 to 10 carbon atoms. Preferred aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid and fumaric acid, and preferred aromatic carboxylic acids are phthalic acids, preferably (ortho)-phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalene dicarboxylic acids. The polyester polyol is obtained by the condensation of these polycarboxylic acids with polyols, i.e., polyhydroxy alcohols, preferably diols or triols having 2 to 12, more preferably 2 to 6 carbon atoms. Particularly preferred are diols based on diols and / or diol ethers having a molecular weight below 180 g / mol, preferably below 140 g / mol, and most preferably monoethylene glycol and / or diethylene glycol. Preferably, the polyester polyols used for the production of PIR contain an excess of polyhydroxy alcohol such that they can also be present in the polyol component in unbound form. Particularly preferred polyester polyols contain a high content of aromatic monomers. PIRs made from such polyester polyols exhibit very high flame retardancy.

[0074] In a preferred embodiment, at least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight of the polyol component used for the preparation of polyisocyanurate has a hydroxyl value of 100 to 450 mg KOH / g, preferably 120 to 400 mg KOH / g, more preferably 140 to 350 mg KOH / g measured according to DIN 53240.

[0075] In addition to the polyester polyol, one or more polyols selected from polyether polyols, polyether polycarbonate polyols, natural oil-based polyols (NOP; as described in WO 2005 / 033167, US2006 / 0293400, WO 2006 / 094227, WO 2004 / 096882, US2002 / 0103091, WO 2006 / 116456, EP 1678232), filled polyols and prepolymer-based polyols can be used in step a).

[0076] As isocyanate b), all isocyanates or polyisocyanates containing at least two isocyanate groups can be used. Suitable isocyanates and polyisocyanates for the purposes of the present invention are organic isocyanates having two or more isocyanate groups. Aliphatic, cycloaliphatic, arylaliphatic isocyanates having 2 or more, preferably 2 to 4 isocyanate groups and mixtures thereof can generally be used. Such aromatic polyfunctional isocyanates are known per se. Preferred are alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene group, such as dodecane 1,12-diisocyanate, 2-ethyltetramethylene 1,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, tetramethylene 1,4-diisocyanate, pentamethylene diisocyanate (PDI) and preferably hexamethylene 1,6-diisocyanate (HMDI), cycloaliphatic diisocyanates such as cyclohexane 1,3- and 1,4-diisocyanates and any mixtures of these isomers, 4,4'-methylenebiscyclohexyl diisocyanate (H12MDI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (abbreviated isophorone diisocyanate or IPDI), hexahydrotolylene 2,4- and 2,6-diisocyanates and the corresponding isomer mixtures, and preferably aromatic diisocyanates and polyisocyanates, such as toluene 2,4- and 2,6-diisocyanates (TDI) and the corresponding isomer mixtures, naphthalene diisocyanate, diethyltoluene diisocyanate, diphenylmethane 4,4'-, 2,4'- and 2,2'-diisocyanates (MDI) and mixtures of polyphenylpolymethylene polyisocyanates (PMDI, also known as polymeric MDI and crude MDI) and their higher condensation analogues having an average functionality of 2 to 4. Other examples are mixtures of crude MDI and toluene diisocyanate (TDI). The organic diisocyanates and polyisocyanates can be used alone or in the form of their mixtures. The corresponding "oligomers" of the diisocyanates (IPDI trimers based on isocyanurates, biurets, uretdiones) can also be used. In addition, it is possible to use prepolymers based on the above isocyanates. It is also possible to use isocyanates modified by incorporation of carbamate, uretdione, isocyanurate, urethane and other groups, i.e. so-called modified isocyanates. Examples of particularly suitable isocyanates are also listed, for example, in EP 1712578, EP 1161474, WO 00 / 58383, US2007 / 0072951, EP 1678232 and WO 2005 / 085310, which are incorporated herein by reference in their entirety.

[0077] Most preferably, organic polyisocyanate isomers of tolylene diisocyanate (toluene 2,4- and 2,6-diisocyanate (TDI), in pure form or as a mixture of isomers of different compositions), diphenylmethane 4,4'-diisocyanate (MDI), "crude MDI" or "polymeric MDI" (containing the 4,4'-isomer of MDI as well as the 2,4'- and 2,2'-isomers and products having more than two rings) and the bicyclic product consisting mainly of a mixture of 2,4'- and 4,4'-isomers known as "pure MDI", and prepolymers derived therefrom. Examples of particularly suitable isocyanates are detailed, for example, in EP 1712578, EP 1161474, WO 00 / 58383, US2007 / 0072951, EP 1678232 and WO 2005 / 085310, which are hereby incorporated by reference in their entirety.

[0078] As catalyst c), all compounds capable of accelerating the reaction of isocyanates with OH-functional groups, NH-functional groups or other isocyanate-reactive groups and with the isocyanates themselves can be used. Here, it is preferred that conventional catalysts known in the art can be utilized, including, for example, amines (cyclic, acyclic; monoamines, diamines, oligomers having one or more amino groups), ammonium compounds, organometallic compounds and metal salts, preferably those of potassium, tin, iron, bismuth. It is also preferred to use mixtures of more than one of these catalysts.

[0079] Foam stabilizers (d) and their use in the production of PIR foams are known to those skilled in the art. As foam stabilizers, in particular, surface-active compounds (surfactants) can be used. Although the use of foam stabilizers is optional, they are preferably used in the production of PIR foams. They can be used to optimize the desired cell structure and the foaming process. These compounds are well-known in the art. For example, siloxanes are described in the following patent specifications, but only their use in classical PU foams (such as molded foams, mattresses, insulation materials, building foams, etc.) is described: CN 103665385, CN103657518, CN 103055759, CN 103044687, US2008 / 0125503, US 2015 / 0057384, EP 1520870A1, EP 1211279, EP 0867464, EP 0867465, EP 0275563. In addition to surface-active Si-containing compounds, Si-free surfactants can also be used. For example, the use of lecithin is described in EP 2295485 A1, and the use of a structure based on vinylpyrrolidone as a foam stabilizer is described in US3746663, but only for the production of rigid PU foams. Other Si-free foam stabilizers are described, for example, in EP 2511328 B1, DE 1020011007479A1, DE3724716 C1, EP 0734404, EP 1985642, DE 2244350, and US 5236961.

[0080] The production of PIR foams using blowing agents is also known in the art. Chemical blowing agents and physical blowing agents can be used. The choice of blowing agent strongly depends on the nature of the system. Depending on the amount of blowing agent used, foams with high or low density are produced. Thus, foams with a density of 5 kg / m 3 to 900 kg / m 3 , preferably 5 to 350, more preferably 8 to 200 kg / m 3 , especially 8 to 150 kg / m 3 can be prepared.

[0081] The preferred physical blowing agents used may be the corresponding compounds having appropriate boiling points. Examples of blowing agents are liquefied CO2, nitrogen, air, volatile liquids such as hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane and n-pentane, hydrofluorocarbons, preferably HFC 245fa, HFC 134a and HFC 365mfc, chlorofluorocarbons, preferably HCFC 141b, hydrofluoroolefins (HFO) or hydrohaloolefins such as, for example, 1234ze, 1234yf, 1233zd(E) or 1336mzz, oxygen-containing compounds such as methyl formate, ketones, preferably acetone, ethers, preferably dimethoxymethane, or chlorinated hydrocarbons, preferably dichloromethane and 1,2-dichloroethane.

[0082] Similarly, optionally, chemical blowing agents that react with the NCO groups to release gas can be used, such as water or formic acid. As chemical blowing agents, one or more compounds that react with the NCO groups by releasing gas, such as water or formic acid, or compounds that react with the NCO groups by releasing gas due to an increase in temperature during the reaction, such as sodium bicarbonate, can be used.

[0083] The optionally present additives f) that can be included in PIR include all substances known from the prior art and used in the production of polyisocyanurates, especially polyisocyanurate foams, such as crosslinking agents and chain extenders, stabilizers against oxidative degradation (referred to as antioxidants), flame retardants, surfactants, biocides, cell-refining additives, cell-opening agents, solid fillers, antistatic additives, nucleating agents, thickeners, dyes, pigments, color pastes, fragrances and emulsifiers, etc.

[0084] The method for producing rigid PIR foams can be carried out by known methods, such as by manual mixing or preferably by means of a foaming machine. If a foaming machine is used for this method, high-pressure or low-pressure machines can be used.

[0085] The polyisocyanurates used in the method of the present invention preferably have an isocyanate index equal to or greater than 150, preferably > 180, more preferably > 250, and most preferably > 250 to 500. Such polyisocyanurates are particularly stable and have very high chemical resistance and / or flame retardancy. Therefore, they show the highest market potential for the PIR recycling method of the present invention.

[0086] In the method of the present invention, the polyisocyanurate is contacted with water in the presence of an organic amine base.

[0087] The preferred organic amine bases are selected from aliphatic amines, aromatic amines, heteroaromatic amines and mixtures thereof. More preferably, the organic amine base is an aliphatic amine containing one or more tertiary nitrogen atoms and / or having a boiling point lower than that of at least one, preferably more than one, and more preferably all of the organic amines obtained as hydrolysis products of polyisocyanurates.

[0088] In the process of the present invention, various organic amine bases can be used to effectively depolymerize PIR, and these organic amine bases can be easily separated from the reaction products of PIR hydrolysis preferably by distillation or extraction.

[0089] Preferably, the organic amine base is used as a non-ionic organic base in the process of the present invention. "Non-ionic" means that the base is not in the form of a salt before being added to the reaction mixture, i.e., it does not contain anions and cations. "Organic amine base" is a compound that contains nitrogen in addition to carbon and hydrogen and reacts with an acid to form a salt compound. Preferably, the "organic amine base" contains one or more CH bonds.

[0090] The organic amine base used in the present invention contains one or more nitrogen atoms. The nitrogen atom can be a primary nitrogen atom (i.e., NH2R), a secondary nitrogen atom (i.e., NHR2) and / or a tertiary nitrogen atom (i.e., NR3), where R is an alkyl group. Preferably, the organic base contains one or more tertiary nitrogen atoms. Without being bound by any theory, the applicant believes that the tertiary nitrogen atom does not form urea when reacting with polyurethane, and thus catalyzes the direct hydrolysis of polyisocyanurate compared with primary or secondary amino groups.

[0091] Contrary to the use of inorganic bases, the use of such organic amine bases of the present invention significantly reduces the amount of salts in the reaction solution, significantly reduces the amount of salts that need to be separated and treated, and improves the sustainability of the process. The inventors have surprisingly found that the organic amine bases used in the present invention can be used without adding a phase transfer catalyst, for example, without adding a quaternary ammonium salt as a phase transfer catalyst. This allows further reduction of the salt load in the reaction mixture and provides additional ecological and economic benefits.

[0092] The organic amine base used in the present invention is preferably an aliphatic amine having a boiling point lower than that of at least one, preferably more than one, and more preferably all of the organic polyamines produced as hydrolysis products of PIR.

[0093] The use of aliphatic organic amine bases allows short reaction times and low temperatures without reducing the polyol yield.

[0094] The preferred organic amine bases are selected from:

[0095] - The base according to formula (1)

[0096] ((R 3 )2N-R 2 )-(O-R 1 )x ) y -N(R 4 ) z (1)

[0097] wherein

[0098] the R 1 groups in the molecule may be the same or different, and the R 2 groups in the molecule may be the same or different, and the R 3 groups in the molecule may be the same or different, and the R 4 groups in the molecule may be the same or different, and wherein

[0099] R 1 are the same or different and are each independently selected from straight-chain or branched-chain alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, most preferably ethylene, propylene or isopropylidene

[0100] R 2 are the same or different and are each independently selected from straight-chain or branched-chain alkylene or hydroxyalkylene groups having 1 to 20, preferably 1 to 18, more preferably 2 to 6, even more preferably 2 to 4 carbon atoms, and if R 2 is a hydroxyalkylene group, then R 2 contains 1 to 5, preferably 1, 2 or 3, more preferably 1 or 2, most preferably 1 hydroxyl group, most preferably ethylene, propylene, butylene, 1,6-hexylene, 2-hydroxypropylene or isopropylidene

[0101] R 3 are the same or different and are each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl

[0102] R 4identical or different and each independently selected from hydrogen, straight-chain or branched-chain, cyclic or cycloaliphatic alkyl having 1 to 20, preferably 1 to 18, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, cycloalkyl residues having 6 to 18 carbon atoms, preferably 6 to 12, more preferably 6 to 10, even more preferably 6 or 7 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, cyclohexyl, isopropyl, tert-butyl, cyclohexyl, methylcyclohexyl, 2-cyclohexylethyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 6-hydroxyhexyl and 2-hydroxyisopropyl, and wherein

[0103] u = 1 to 14, preferably 1 to 6

[0104] v = 1 to 14, preferably 1 to 6

[0105] w = 1 to 14, preferably 1 to 6

[0106] x = 0 or 1

[0107] y = 0 to 3

[0108] z = 0 to 3, provided that if z = 3, then one, preferably two, more preferably all three R 4 is not hydrogen,

[0109] y + z = 3,

[0110] - a base according to formula (2)

[0111] ((R 6 )2N-R 5 ) a (H) b N) d -CZ-(N(R 7 )2) c (2)

[0112] wherein

[0113] the R 5 groups in the molecule may be the same or different, the R 6 residues in the molecule may be the same or different, and the R 7 residues in the molecule may be the same or different, and wherein

[0114] R 5identical or different and each independently selected from straight-chain or branched alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, where one or more CH2 groups may be replaced by O to form an ether bond, and preferably, R 5 is ethylene, propylene or isopropylidene

[0115] R 6 identical or different and each independently selected from hydrogen, straight-chain or branched alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl,

[0116] R 7 identical or different and each independently selected from hydrogen, straight-chain or branched alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, and where

[0117] Z = O or NH,

[0118] u = 1 to 14, preferably 1 to 6

[0119] v = 1 to 14, preferably 1 to 6

[0120] w = 1 to 14, preferably 1 to 6

[0121] a = 0, 1 or 2

[0122] b = 0, 1 or 2

[0123] a + b = 2

[0124] c = 0, 1 or 2

[0125] d = 0, 1 or 2

[0126] c + d = 2

[0127] - Cyclic or bicyclic, aromatic or non - aromatic nitrogen - containing organic bases containing 4 to 20 carbon atoms, preferably 5 to 14, more preferably 5 to 12, and most preferably 6 to 10 carbon atoms and 1 to 4 nitrogen atoms, preferably 1 to 3, more preferably 1, 2 or 3 nitrogen atoms. Optionally, the cyclic or bicyclic, aromatic or non - aromatic nitrogen - containing organic base contains one or more O atoms and / or bears one or more substituents, such as straight - chain or branched - chain alkyl or alkenyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight - chain or branched - chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2 - hydroxyethyl, 3 - hydroxypropyl, 2 - hydroxypropyl, 2 - hydroxyisopropyl, or one or more functional groups containing N and / or O and / or two or more cyclic or bicyclic non - aromatic nitrogen - containing organic rings are bonded to each other via an alkylene or ether - alkylene bond having 1 to 12, preferably 1 to 6 carbon atoms,

[0128] - and mixtures thereof.

[0129] The most preferred organic amine bases are selected from:

[0130] - Trialkylamines according to formula (3), as a preferred embodiment of formula (1),

[0131] NR 4 R 4 'R 4 ”(3)

[0132] wherein R 4 、R 4' 、R 4” are the same or different and are independently selected from hydrogen, straight - chain or branched - chain, cyclic or cycloaliphatic alkyl groups having 1 to 20, preferably 1 to 18, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1, 2 or 3 carbon atoms, straight - chain or branched - chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, and cycloalkyl residues having 6 to 18 carbon atoms, preferably 6 to 12, more preferably 6 to 10, and even more preferably 6 or 7 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) wH, most preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, cyclohexyl, isopropyl, tert-butyl, cyclohexyl, methylcyclohexyl, 2-cyclohexylethyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 6-hydroxyhexyl and 2-hydroxyisopropyl,

[0133] u = 1 to 14, preferably 1 to 6

[0134] v = 1 to 14, preferably 1 to 6

[0135] w = 1 to 14, preferably 1 to 6,

[0136] provided that R 4 , R 4 ' and R 4 ” one of them, preferably two, more preferably all three are not hydrogen.

[0137] - The polyamine according to formula (4), as another preferred embodiment of formula (1),

[0138] ((R 3 )2N-R 2 )3N (4)

[0139] wherein

[0140] R 2 are the same or different and are independently selected from straight-chain or branched-chain alkylene or hydroxyalkylene having 1 to 20, preferably 1 to 18, more preferably 2 to 6, even more preferably 2 to 4 carbon atoms, and if R 2 is hydroxyalkyl, then R 2 contains 1 to 5, preferably 1, 2 or 3, more preferably 1 or 2, most preferably 1 hydroxyl group, most preferably ethylene, propylene or isopropyl

[0141] R 3 are the same or different and are independently selected from hydrogen, straight-chain or branched-chain alkyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl,

[0142] u = 1 to 14, preferably 1 to 6

[0143] v = 1 to 14, preferably 1 to 6

[0144] w = 1 to 14, preferably 1 to 6

[0145] - The polyamine according to formula (5), as a further preferred embodiment of formula (1),

[0146] ((R 3 )2N-R 2 )-(O-R 1 ) x ) y -N(R 4 ) z (5)

[0147] where x = 0 or 1, y = 1 or 2, z = 1 or 2, and y + z = 3, and where

[0148] R 1 are the same or different and are each independently selected from straight-chain or branched-chain alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, most preferably ethylene, propylene or isopropylidene,

[0149] R 2 are the same or different and are each independently selected from straight-chain or branched-chain alkylene or hydroxyalkylene groups having 1 to 20, preferably 1 to 18, more preferably 2 to 6, even more preferably 2 to 4 carbon atoms, and if R 2 is a hydroxyalkyl group, then R 2 contains 1 to 5, preferably 1, 2 or 3, more preferably 1 or 2, most preferably 1 hydroxyl group, most preferably ethylene, propylene, butylene, 1,6-hexylene, 2-hydroxypropylene or isopropylidene,

[0150] R 3 are the same or different and are each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl,

[0151] R 4 are the same or different and are each independently selected from hydrogen, straight-chain or branched-chain, cyclic or cycloaliphatic alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O)v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, cyclohexyl, isopropyl, tert-butyl, cyclohexyl, methylcyclohexyl, 2-cyclohexylethyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 6-hydroxyhexyl and 2-hydroxyisopropyl

[0152] u = 1 to 14, preferably 1 to 6

[0153] v = 1 to 14, preferably 1 to 6

[0154] w = 1 to 14, preferably 1 to 6

[0155] - The polyaminoalkylurea according to formula (6), as a preferred embodiment of formula (2),

[0156] ((R 6 )2N-R 5 ) a (H) b N) d -CO-(N(R 7 )2) c (6)

[0157] wherein

[0158] R 5 are the same or different and are each independently selected from straight-chain or branched-chain alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, wherein one or more CH2 groups may be replaced by O to form an ether bond, preferably, R 5 is ethylene, propylene or isopropylene

[0159] R 6 are the same or different and are each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl,

[0160] R 7identical or different and each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl, and wherein

[0161] u = 1 to 14, preferably 1 to 6

[0162] v = 1 to 14, preferably 1 to 6

[0163] w = 1 to 14, preferably 1 to 6

[0164] a = 0, 1 or 2

[0165] b = 0, 1 or 2

[0166] a + b = 2

[0167] c = 0, 1 or 2

[0168] d = 0, 1 or 2

[0169] c + d = 2,

[0170] - The guanidine-based organic base according to formula (7), as a further preferred embodiment of formula (2),

[0171] ((R6)2N-R5) a (H) b N) d -C(NH)-(N(R7)2) c (7)

[0172] wherein

[0173] R 5 identical or different and each independently selected from straight-chain or branched-chain alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, wherein one or more CH2 groups may be replaced by O to form an ether bond, preferably, R 5 is ethylene, propylene or isopropylene

[0174] R 6Identical or different, and independently selected from each other hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl,

[0175] R 7 Identical or different, and independently selected from each other hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, isopropyl, and wherein

[0176] u = 1 to 14, preferably 1 to 6

[0177] v = 1 to 14, preferably 1 to 6

[0178] w = 1 to 14, preferably 1 to 6

[0179] a = 0, 1 or 2

[0180] b = 0, 1 or 2

[0181] a + b = 2

[0182] c = 0, 1 or 2, preferably 0 or 1, more preferably 0

[0183] d = 0, 1 or 2, preferably 1 or 2, more preferably 2

[0184] c + d = 2,

[0185] - and mixtures thereof.

[0186] The most preferred organic amine bases are selected from triethylamine, tripropylamine, N,N-dimethyl-N-propylamine, N,N-dimethyl-N-butylamine, N,N-dimethyl-N-pentylamine, N,N-dimethyl-N-hexylamine, N,N-dimethyl-N-cyclohexylamine, N,N-dimethyl-N-heptylamine, N,N-dimethyl-N-octylamine, N,N-diethyl-N-propylamine, N,N-diethyl-N-butylamine, N,N-diethyl-N-pentylamine, N,N-diethyl-N-hexylamine, N,N-diethyl-N-cyclohexylamine, N,N-diethyl-N-heptylamine, N,N-diethyl-N-octylamine, tetramethylethylenediamine (TMEDA), tetramethyl-1,3-propanediamine (TMPDA), tetramethyl-1,4-butanediamine (TMBDA), tetramethyl-1,6-hexanediamine (TMHMDA), pentamethyldiethylenetriamine (PMDETA), N,N,N'N'-tetramethyl-bis(aminoethyl) ether, N,N'-dimethyl-piperazine, 1,4-diazabicyclo(2,2,2)octane (TEDA), trimethyl-triaza-cyclononane (TACN); dimethylethanolamine, dimethylaminoethoxyethanol, N,N-dimethylaminoethyl-N'-methyl-ethanolamine, tetramethylguanidine, N,N-bis(3-dimethylaminopropyl)-N-(2-hydroxypropyl)amine, N,N-dimethyl-N',N'-bis(2-hydroxypropyl)-1,3-propanediamine, dimethylaminopropylamine (DMAPA); N-methyl-N-2-hydroxypropyl-piperazine, bis(dimethylaminopropyl)amine, dimethylaminopropylurea, N,N'-bis(3-dimethylaminopropyl)urea, 1,3-bis(dimethylamino)-2-propanol, 6-dimethylamino-1-hexanol, N,N'-bis(2-hydroxypropyl)piperazine, N-(2-hydroxypropyl)-morpholine, 1,2-dimethylimidazole, 1-ethylimidazole, N-methyl-pyrrolidine, N-ethyl-pyrrolidine, N-(2-hydroxyethyl)-pyrrolidine, N-(2-hydroxypropyl)-pyrrolidine, N-propyl-pyrrolidine, N-allyl-pyrrolidine, N-methyl-piperidine, N-ethyl-piperidine, N-(2-hydroxyethyl)-piperidine, N-(2-hydroxypropyl)-piperidine, N-propyl-piperidine, N-allyl-piperidine and mixtures thereof.

[0187] Instead of aliphatic amines, aromatic amines can be used in the present invention. Preferably, aromatic amines related to the isocyanates used for preparing PIR are used. Such a method is beneficial because the amine used as the hydrolysis catalyst is the same as the amine recovered from PIR and does not need to be separated from each other. The amine formed during hydrolysis can act as a cocatalyst together with the amine base added to the reaction mixture. This allows reducing the amount of amine base that must be added to the reaction mixture. Additionally, the amine recovered from the method of the present invention can be reused as a hydrolysis catalyst in the method of the present invention.

[0188] Further preferably, the following aromatic amine catalysts that can be used are selected from aniline, preferably dimethylaniline and 4,4'-methylenedianiline (MDA), pyridine, and imidazoline, such as 1,3-dimethyl-2-imidazolidinone (DMI). Compared with aliphatic amines, these aromatic amine catalysts are less sensitive to oxidation. By-products such as DMF or formaldehyde formed due to the oxidation process are less likely to form.

[0189] The use of the amine bases described previously allows the process of the present invention to be carried out in standard equipment, preferably in a steel reactor, without special corrosion protection, thus greatly contributing to reducing the investment cost of the plant. Very inexpensive bases can also be used, which helps to reduce the operating cost.

[0190] The amount of the organic amine base in the reaction mixture must be sufficient to catalyze the required hydrolysis of the polyisocyanurate at a feasible rate. Preferably, the amine is used in a stoichiometric amount or in excess compared to the polyisocyanurate. More preferably, the weight ratio of the total amount of the organic amine base to the polyisocyanurate is from 1:100 to 50:1, preferably from 1:50 to 25:1, more preferably from 1:10 to 20:1, even more preferably from 1:5 to 10:1, and most preferably from 1:2 to 3:1. Preferably, the base is used in the form of an aqueous base solution containing the base and water, and even more preferably as a saturated base solution.

[0191] Although PIR can react with amines and water in the process of the present invention, the polyisocyanurate can also be contacted with water in the presence of an organic amine base and a phase transfer catalyst, preferably a phase transfer catalyst selected from quaternary ammonium salts containing ammonium cations and having 6 to 30 carbon atoms and organic sulfonates containing at least 7 carbon atoms. The use of the phase transfer catalyst has been shown to increase the yield of the reaction product and allow the reaction to be carried out at a lower temperature and with a reduced reaction time.

[0192] The preferred quaternary ammonium salts used as phase transfer catalysts have the general formula structure R1R2R3R4NX, where R1, R2, R3, and R4 are the same or different and are hydrocarbon groups selected from alkyl, aryl, and arylalkyl, and X is selected from halide ions, preferably chloride ions and / or bromide ions, hydrogen sulfate, alkyl sulfate, preferably methyl sulfate and ethyl sulfate, carbonate, bicarbonate, carboxylate, preferably acetate, or hydroxide.

[0193] More preferably, R1, R2, R3, and R4 and X are defined as follows:

[0194] - R1 and R2 are the same or different and are alkyl groups having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, particularly preferably 1 to 5, and most preferably 1 to 4 carbon atoms, where the alkyl group can be straight-chain, branched-chain, cyclic, saturated, or unsaturated, and most preferably a straight-chain saturated alkyl group,

[0195] - R3 is selected from alkyl groups having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, particularly preferably 1 to 5, and most preferably 1 to 4 carbon atoms, aryl groups having 6 to 14, preferably 6 to 12, and most preferably 6 to 10 carbon atoms, and aralkyl groups having 7 to 14, preferably 7 to 12, and most preferably 7 to 10 carbon atoms, where the alkyl group can be straight-chain, branched-chain, cyclic, saturated or unsaturated, most preferably straight-chain, and

[0196] - R4 is selected from alkyl groups having 3 to 12, preferably 3 to 10, more preferably 3 to 7, and most preferably 4 to 6 carbon atoms, aryl groups having 6 to 14, preferably 6 to 12, and most preferably 6 to 10 carbon atoms, and aralkyl groups having 7 to 14, preferably 7 to 12, and most preferably 7 to 10 carbon atoms, where the alkyl group can be straight-chain, branched-chain, cyclic, saturated or unsaturated, most preferably straight-chain saturated, and

[0197] - X is selected from halide ions, preferably chloride ions and / or bromide ions, hydrogen sulfate, alkyl sulfate, preferably methyl sulfate and ethyl sulfate, carbonate, bicarbonate, acetate or hydroxide.

[0198] Even more preferably, R1 to R4 are selected from the definitions provided above, such that

[0199] The total number of carbon atoms in the quaternary ammonium cation is 6 to 14, preferably 7 to 14, more preferably 8 to 13

[0200] or

[0201] The total number of carbon atoms in the quaternary ammonium cation is 15 to 30, preferably 15 to 28, more preferably 15 to 24, even more preferably 16 to 22, and most preferably 16 to 20.

[0202] Particularly preferably, R1 to R4 and X are selected such that the total number of carbon atoms in the quaternary ammonium salt is 6 to 14, preferably 7 to 14, more preferably 8 to 13,

[0203] or

[0204] R1 to R4 and X are selected such that the total number of carbon atoms in the quaternary ammonium salt is 15 to 30, preferably 15 to 28, more preferably 15 to 24, even more preferably 16 to 22, and most preferably 16 to 20.

[0205] Although the addition of even trace amounts of the phase transfer catalyst will accelerate the hydrolysis rate, it is preferred to use at least 0.5% by weight of the catalyst, more preferably 0.5 to 15% by weight, even more preferably 1 to 10% by weight, particularly preferably 1 to 8% by weight, especially preferably 1 to 7% by weight, and most preferably 2 to 6% by weight, based on the weight of the polyisocyanurate.

[0206] In another preferred embodiment, during or after the completion of hydrolysis, one or more inorganic bases comprising alkali metal cations and / or alkaline earth metal cations, preferably an inorganic base comprising alkali metal cations, are added to the reaction mixture in order to obtain alkali metal salts or alkaline earth metal salts or mixed alkali metal and alkaline earth metal salts of one or more carboxylic acids, wherein each molecule of the one or more carboxylic acids comprises equal to or greater than 2 carboxylic acid groups and corresponds to the carboxylic acids used for preparing polyester polyols for preparing polyisocyanurates, and the carboxylic acids are formed during hydrolysis. It has been shown that such alkali metal salts or alkaline earth metal salts or mixed alkali metal and alkaline earth metal salts of the one or more carboxylic acids, preferably alkali metal salts, can be separated more easily from the other components of the reaction solution than the ammonium salts formed additionally during the hydrolysis reaction. Without being bound by any theory, the inventors believe that the better solubility of such alkali metal salts or alkaline earth metal salts or mixed alkali metal and alkaline earth metal salts in water contributes to this improvement.

[0207] Preferably, the alkali metal base is selected from alkali metal phosphates, alkali metal hydrogen phosphates, alkali metal carbonates, alkali metal silicates, alkali metal bicarbonates, alkali metal acetates, alkali metal sulfites, ammonium hydroxide and mixtures thereof. More preferably, the alkali metals are selected from Na, K and Li and mixtures thereof, most preferably Na and K and mixtures thereof.

[0208] The preferred weight ratio of the total amount of the inorganic base to the polyisocyanurate is from 5:1 to 1:120, preferably from 4:1 to 1:80, more preferably from 3:1 to 1:40, even more preferably from 2:1 to 1:20, and most preferably from 1:1 to 1:10. More preferably, the amount of the inorganic base is selected such that one or more carboxylic acids are quantitatively converted into alkali metal salts or alkaline earth metal salts or mixed alkali metal and alkaline earth metal salts, preferably alkali metal salts.

[0209] The inorganic base can be added to the reaction mixture as a solid substance or in an aqueous solution. Preferably, the inorganic base is used in the form of a saturated aqueous base solution.

[0210] Water acts as a reactant in the hydrolysis reaction of the present invention, and thus does not need to be present in a stoichiometric excess relative to the isocyanurate functional groups in the polymer to be hydrolyzed. Generally, it is desirable to use a large amount of water so that it can conveniently serve as a reaction medium and solvent or carrier for strong bases and activators. For these reasons, water is preferably present in a concentrated (liquid) form. Generally, the weight ratio of PIR to water is from 3:1 to 1:15.

[0211] Preferably, the polyisocyanurate is contacted with water and an organic amine base, or with water, an organic amine base and a phase transfer catalyst.

[0212] at a temperature of from 80°C to 220°C, preferably from 100°C to 200°C, more preferably from 120°C to 190°C, most preferably from 140°C to 180°C

[0213] and / or

[0214] for a period of from 1 minute to 48 hours, preferably from 1 minute to 40 hours, more preferably from 5 minutes to 35 hours, even more preferably from 10 minutes to 30 hours, particularly preferably from 20 minutes to 24 hours, especially preferably from 30 minutes to 18 hours, most preferably from 30 minutes to 16 hours

[0215] and / or

[0216] at atmospheric pressure or at a pressure of from 1 to 30 bar, 2 to 20 bar, more preferably 3 to 15 bar. These reaction conditions provide economic benefits in terms of energy consumption and space-time yield. If the temperature is too low, the conversion may be incomplete or the reaction time will become too long. If the reaction temperature is too high or the reaction time exceeds the ranges given previously, an increase in the formation of by-products is observed and the energy consumption increases to an unacceptable level. The formation of by-products can lead to an undesired coloring of the recovered product, which results in the need for additional purification steps. It has been found that conducting the reaction at elevated pressure shortens the reaction time and allows operation at a lower temperature.

[0217] To facilitate PIR, preferably the treatment of PIR foam, it is preferably desired to chop, crush, grind or otherwise comminute the PIR such that it is in the form of relatively small particles or granules. If the PIR is a foam, it can be partially or completely compressed before contacting with water and the organic amine base. If the PIR is in solid form, an initial comminution step is highly advantageous in order to maximize the surface area available for the reaction (thus reducing the reaction time required to achieve the desired level of hydrolysis).

[0218] The process of the present invention will result in an effective hydrolytic cleavage of the isocyanurate bonds present in the treated PIR. Under the reaction conditions, the polyester polyol obtained after rupture of the ring of the isocyanurate bond is further hydrolyzed to obtain the relevant carboxylic acids and polyols.

[0219] Thus, in the process of the present invention, there is obtained

[0220] one or more carboxylic acids containing equal to or greater than 2 carboxylic acid groups per molecule (which correspond to the carboxylic acids used for preparing the polyester polyol for preparing the polyisocyanurate),

[0221] and

[0222] one or more polyols (which correspond to the polyols used for preparing the polyester polyol for preparing the polyisocyanurate),

[0223] and

[0224] one or more organic amines and / or polyamines corresponding to the organic isocyanate or polyisocyanate used for preparing polyisocyanurate).

[0225] Preferably, one or more carboxylic acids obtained after hydrolysis are selected from phthalic acids, preferably (o)-phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalenedicarboxylic acids, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid, fumaric acid and mixtures thereof.

[0226] Also preferably, one or more polyols obtained after hydrolysis are diols based on diols and / or diol ethers having a molecular weight lower than 180 g / mol, preferably lower than 140 g / mol, particularly preferably monoethylene glycol and / or diethylene glycol.

[0227] Further preferably, one or more organic amines and / or polyamines obtained after hydrolysis are selected from dodecane 1,12-diamine, 2-ethyltetramethylene 1,4-diamine, 2-methylpentamethylene 1,5-diamine, tetramethylene 1,4-diamine, pentamethylenediamine (PDA) and preferably hexamethylene 1,6-diamine (HMDA), alicyclic diamines such as cyclohexane 1,3- and 1,4-diamine and any mixtures of these isomers, 4,4'-methylenebiscyclohexyl diisocyanate (H12MDI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (abbreviated as isophorone diamine or IPDA), hexahydrotolylene 2,4- and 2,6-diamine and corresponding isomer mixtures, and preferably aromatic diamines and polyisocyanates, such as toluene 2,4- and 2,6-diamine (TDA) and corresponding isomer mixtures, naphthalenediamine, diethyltoluenediamine, diphenylmethane 4,4'-, 2,4'- and 2,2'-diamine (MDA) and mixtures of polyphenylpolymethylene polyamines and their higher condensation analogues having an average functionality of 2 to 4.

[0228] The hydrolysis reaction can be carried out as a batch, continuous or semi-continuous process in any suitable vessel or other device (e.g., a stirred tank reactor or a screw extruder). It is generally preferred to agitate or stir the reaction components in order to ensure intimate contact, rapid hydrolysis rate and proper temperature control.

[0229] Compared with the prior art processes, the method of the present invention is advantageous because the hydrolysis reaction can be carried out as a one-step process. Preferably, the PIR does not react with pure amine or pure water before hydrolysis with water and an organic amine base or with water, an organic amine base and a phase transfer catalyst.

[0230] More preferably, the method of the present invention does not include the steps of separating the reaction product of the organic amine base and PIR and then hydrolyzing the separated reaction product.

[0231] After the hydrolysis step is completed, it is preferred to separate the reaction products from each other and optionally perform a purification step. Preferred separation and purification methods are selected from filtration, membrane separation, phase separation, chromatography, distillation, extraction, and combinations of these methods. Preferably, the amine component, i.e., the amine base and / or amine, obtained as the hydrolyzed reaction product is separated from other components via distillation or extraction, more preferably via distillation.

[0232] The recovered products of the method of the present invention, in particular one or more carboxylic acids and / or polyols and / or organic amines and / or polyamines, can be reused in the production of new chemicals, preferably polyurethanes, preferably polyurethane foams, or polyisocyanurates, preferably polyisocyanurate foams. The inventors have found that they can be used in the production of high-quality PIR polyurethane foams even without the addition of the original polyol. This is an important achievement.

[0233] The recovered amine can be converted to an organic polyisocyanate by conventional methods and similarly used as a component of polyurethanes or PIRs.

[0234] Without further elaboration, it is believed that those skilled in the art can make the fullest use of the present invention with the foregoing description. Accordingly, the following examples are to be considered merely illustrative and not limiting of the claims or the remainder of the disclosure in any way. Examples

[0235] Preparation of PIR Foam to be Recycled

[0236] To produce the PIR foam for the hydrolysis test described in Example 1 below, the formulation described in Table 1 was used. The PIR foam was produced by manual mixing. For this purpose, the polyol, flame retardant, catalyst, water, foam stabilizer, and blowing agent were weighed into a beaker and mixed for 30 s at 1000 rpm using a disk stirrer (6 cm in diameter). The amount of blowing agent evaporated during the mixing operation was determined by reweighing and replenishing. Subsequently, isocyanate (MDI) was added, and the reaction mixture was stirred for 5 s at 3000 rpm using the described stirrer. In the case of in-situ pouring of the foam, the foaming was achieved in the beaker itself; otherwise, the mixture was transferred to a paper-lined box with a bottom area of 27×14 cm.

[0237] Table 1: PIR Formulation

[0238] Components Weight ratio Polyester polyol* 100 Amine catalyst** 0.5 Trimerization catalyst*** 3.5 Foam stabilizer**** 2 Water 0.6 Flame retardant***** 15 Cyclopentane / isopentane 70∶30 8 MDI****** 263

[0239] *From Stepan PS 3152, OH number 315 mg KOH / g

[0240] **From Evonik Operations GmbH 5 (Pentamethyldiethylenetriamine)

[0241] ***From Evonik Operations GmbH 70LO

[0242] ****From Evonik Operations GmbH B 8411

[0243] *****From ICL Industrial Products PCF

[0244] ******Polymeric MDI, 200 mPa·s, 31.5% NCO, functionality 2.7

[0245] Example 1

[0246] Grind the PIR foam prepared as described above. Transfer 120 g of the ground PIR foam together with 862 g BL 19 (Bis(2-dimethylaminoethyl) ether) and 218 g of water into a 5 L pressure reactor. Heat the mixture to 170 °C and stir for 5 h. Establish a pressure of approximately 11 bar. A turbid, slightly brownish completely liquid product is obtained, which shows phase separation after standing for 12 h. C-NMR shows only trace amounts of carbamate groups, urea groups, and isocyanurate groups, and indicates a conversion rate > 98%.

[0247] Example 2

[0248] Grind the PIR foam prepared as described above. Transfer 100 g of the ground PIR foam together with 718 g of 1,2-dimethylimidazole and 182 g of water into a 2 L pressure reactor. Heat the mixture to 170 °C and stir for 5 h. Establish a pressure of approximately 8 - 10 bar. A turbid, slightly brownish completely liquid product is obtained. C-NMR shows only trace amounts of carbamate groups, urea groups, and isocyanurate groups, and indicates a conversion rate > 98%.

[0249] Example 3

[0250] Grind the PIR foam prepared as described above. Transfer 100 g of the ground PIR foam together with 718 g 206 (a tertiary amine catalyst) was transferred together with 182 g of water to a 2 L pressure reactor. The mixture was heated to 170 °C and stirred for 5 h. A pressure of about 15 - 17 bar was established. A turbid, slightly yellowish, completely liquid product was obtained, which showed phase separation after standing. C-NMR showed only trace amounts of carbamate groups, urea groups and isocyanurate groups and indicated a conversion > 98%.

Claims

1. A method for hydrolyzing a polyisocyanurate, characterized in that, the polyisocyanurate is produced by reacting one or more polyols selected from polyester polyols, mixtures of polyester polyols, and mixtures of polyester polyols and polyether polyols with an excess of one or more isocyanates selected from organic isocyanates, mixtures of organic isocyanates, organic polyisocyanates, mixtures of organic polyisocyanates, and mixtures of organic isocyanates and organic polyisocyanates, and characterized in that, the polyisocyanurate is contacted with water in the presence of an organic amine base to produce: one or more carboxylic acids each molecule of which contains equal to or more than 2 carboxylic acid groups, corresponding to the carboxylic acids used for preparing the polyester polyol which is used for preparing the polyisocyanurate, and one or more polyols, corresponding to the polyols used for preparing the polyester polyol which is used for preparing the polyisocyanurate, and one or more organic amines and / or polyamines, corresponding to the organic isocyanate or polyisocyanate used for preparing the polyisocyanurate, and characterized in that the reaction mixture containing the polyisocyanurate, water and the organic amine base is a stirred homogeneous or heterogeneous mixture during hydrolysis, preferably a solution or an emulsion or a dispersion or a combination thereof.

2. The method according to claim 1, It is characterized in that wherein the polyisocyanurate is contacted with water in the presence of an organic amine base and a phase transfer catalyst, preferably a phase transfer catalyst selected from quaternary ammonium salts containing ammonium cations having 6 to 30 carbon atoms and organic sulfonates containing at least 7 carbon atoms.

3. The method according to claim 1 or 2, It is characterized in that wherein the organic amine base is selected from aliphatic amines, aromatic amines, heteroaromatic amines and mixtures thereof, preferably, the organic amine base is an aliphatic amine containing one or more tertiary nitrogen atoms and / or having a boiling point lower than the boiling point of at least one, preferably more than one, more preferably all of the organic amines obtained as products of the hydrolysis of the polyisocyanurate.

4. The method according to any one of claims 1 to 3, Characterized in that, wherein the organic amine base is selected from: - the base according to formula (1) ((R 3 )2N-R 2 )-(O-R 1 ) x ) y -N(R 4 ) z (1) where R in the molecule 1 groups can be the same or different, and the R 2 groups can be the same or different, and the R 3 groups can be the same or different, and the R 4 groups can be the same or different, and wherein R 1 identical or different and each independently selected from straight-chain or branched alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, most preferably ethylene, propylene or isopropylene R 2 are the same or different and are each independently selected from straight-chain or branched alkylene or hydroxyalkylene groups having 1 to 20, preferably 1 to 18, more preferably 2 to 6, even more preferably 2 to 4 carbon atoms, and if R 2 is hydroxyalkylene, then R 2 contains 1 to 5, preferably 1, 2 or 3, more preferably 1 or 2, most preferably 1 hydroxy group, and is most preferably ethylene, propylene, butylene, 1,6-hexylene, 2-hydroxypropylene or isopropylidene R 3 Identical or different, and each independently selected from hydrogen, a straight-chain or branched-chain alkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, a straight-chain or branched-chain hydroxyalkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl, R 4 identical or different and each independently selected from hydrogen, a straight-chain, branched-chain, cyclic or cycloaliphatic alkyl group having 1 to 20, preferably 1 to 18, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1, 2 or 3 carbon atoms, a straight-chain or branched-chain hydroxyalkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, a cycloalkyl residue having 6 to 18 carbon atoms, preferably 6 to 12, more preferably 6 to 10, even more preferably 6 or 7 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, cyclohexyl, isopropyl, tert-butyl, cyclohexyl, methylcyclohexyl, 2-cyclohexylethyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 6-hydroxyhexyl and 2-hydroxyisopropyl, and wherein u = 1 to 14, preferably 1 to 6 v = 1 to 14, preferably 1 to 6 w = 1 to 14, preferably 1 to 6 x = 0 or 1 y = 0 to 3 z = 0 to 3, provided that if z = 3, then one, preferably two, more preferably all three R 4 is not hydrogen, y + z = 3, - the base according to formula (2) ((R 6 )2N-R 5 ) a (H) b N) d -CZ-(N(R 7 )2) c (2) where R in the molecule 5 groups can be the same or different, and the residue R in the molecule 6 groups can be the same or different, and the residue R in the molecule 7 groups can be the same or different, and wherein R 5 identical or different and each independently selected from straight-chain or branched alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, wherein one or more CH2 groups can be replaced by O to form an ether bond, preferably, R 5 is ethylene, propylene or isopropylidene R 6 identical or different and each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl, R 7 are the same or different and are each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, and wherein Z = O or NH, u = 1 to 14, preferably 1 to 6 v = 1 to 14, preferably 1 to 6 w = 1 to 14, preferably 1 to 6 a = 0, 1 or 2 b = 0, 1 or 2 a + b = 2 c = 0, 1 or 2 d = 0, 1 or 2 c + d = 2 -A cyclic or bicyclic, aromatic or non-aromatic nitrogen-containing organic base containing 4 to 20 carbon atoms, preferably 5 to 14, more preferably 5 to 12, and most preferably 6 to 10 carbon atoms and 1 to 4 nitrogen atoms, preferably 1 to 3, more preferably 1, 2 or 3 nitrogen atoms. Optionally, the cyclic or bicyclic, aromatic or non-aromatic nitrogen-containing organic base contains one or more O atoms and / or carries one or more substituents, such as a straight-chain or branched-chain alkyl or alkenyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, a straight-chain or branched-chain hydroxyalkyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl, or one or more functional groups containing N and / or O and / or two or more cyclic or bicyclic non-aromatic nitrogen-containing organic rings are bonded to each other via an alkylene or ether-alkylene bond having 1 to 12, preferably 1 to 6 carbon atoms, - and mixtures thereof.

5. The method according to claim 4, It is characterized in that wherein the organic amine base is selected from: - a trialkylamine according to formula (3) NR 4 R 4 'R 4 ”(3) wherein R 4 , R 4' , R 4” are the same or different and are independently selected from hydrogen, straight-chain or branched-chain, cyclic or cycloaliphatic alkyl having 1 to 20, preferably 1 to 18, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, cycloalkyl residue having 6 to 18 carbon atoms, preferably 6 to 12, more preferably 6 to 10, even more preferably 6 or 7 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, cyclohexyl, isopropyl, tert-butyl, cyclohexyl, methylcyclohexyl, 2-cyclohexylethyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 6-hydroxyhexyl and 2-hydroxyisopropyl, u = 1 to 14, preferably 1 to 6 v = 1 to 14, preferably 1 to 6 w = 1 to 14, preferably 1 to 6 The condition is R 4 , R 4' and R 4” One of, preferably two, more preferably all three of which are not hydrogen, - a polyamine according to formula (4) ((R 3 )2N-R 2 )3N(4) where R 2 are the same or different and are each independently selected from straight-chain or branched alkylene or hydroxyalkylene groups having 1 to 20, preferably 1 to 18, more preferably 2 to 6, even more preferably 2 to 4 carbon atoms, and if R 2 is a hydroxyalkyl group, then R 2 contains 1 to 5, preferably 1, 2 or 3, more preferably 1 or 2, most preferably 1 hydroxy group, most preferably ethylene, propylene, butylene, 1,6-hexylene, 2-hydroxypropylene or isopropylidene R 3 Identical or different, and each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl, u = 1 to 14, preferably 1 to 6 v = 1 to 14, preferably 1 to 6 w = 1 to 14, preferably 1 to 6 - a polyamine according to formula (5) (((R 3 )2N-R 2 )-(O-R 1 ) x ) y -N(R 4 ) z (5) where x = 0 or 1, y = 1 or 2, z = 1 or 2, and y + z = 3, and where R 1 identical or different and each independently selected from straight-chain or branched alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, most preferably ethylene, propylene or isopropylene, R 2 are the same or different and are each independently selected from straight-chain or branched alkylene or hydroxyalkylene groups having 1 to 20, preferably 1 to 18, more preferably 2 to 6, more preferably 2 to 4 carbon atoms, and if R 2 is a hydroxyalkyl group, then R 2 contains 1 to 5, preferably 1, 2 or 3, more preferably 1 or 2, most preferably 1 hydroxy group, most preferably ethylene, propylene, butylene, 1,6-hexylene, 2-hydroxypropylene or isopropylidene, R 3 Identical or different, and each independently selected from hydrogen, a straight-chain or branched-chain alkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, a straight-chain or branched-chain hydroxyalkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, R 4 Identical or different and each independently selected from hydrogen, straight-chain or branched-chain, cyclic or alicyclic alkyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, cyclohexyl, isopropyl, tert-butyl, cyclohexyl, methylcyclohexyl, 2-cyclohexylethyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 6-hydroxyhexyl and 2-hydroxyisopropyl u = 1 to 14, preferably 1 to 6 v = 1 to 14, preferably 1 to 6 w = 1 to 14, preferably 1 to 6 - Polyaminoalkylurea according to formula (6) (((R 6 )2N-R 5 ) a (H) b N) d -CO-(N(R 7 )2) c (6) wherein R 5 are the same or different and are each independently selected from straight-chain or branched alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, where one or more CH2 groups can be replaced by O to form an ether bond, and preferably, R 5 is ethylene, propylene or isopropylidene R 6 identical or different and each independently selected from hydrogen, a straight-chain or branched alkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, a straight-chain or branched hydroxyalkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl, R 7 are the same or different and are each independently selected from hydrogen, a straight-chain or branched alkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, a straight-chain or branched hydroxyalkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably hydrogen, methyl, ethyl, propyl, isopropyl, and wherein u = 1 to 14, preferably 1 to 6 v = 1 to 14, preferably 1 to 6 w = 1 to 14, preferably 1 to 6 a = 0, 1 or 2 b = 0, 1 or 2 a + b = 2 c = 0, 1 or 2 d = 0, 1 or 2 c + d = 2, - Organic base containing guanidine group according to formula (7) (((R6)2N - R5) a (H) b N) d -C(NH)-(N(R7)2) c (7) wherein R 5 are the same or different and are each independently selected from straight-chain or branched alkylene groups having 1 to 10, preferably 2 to 6, more preferably 2 to 4 carbon atoms, where one or more CH2 groups can be replaced by O to form an ether bond, preferably, R 5 is ethylene, propylene or isopropylidene R 6 identical or different and each independently selected from hydrogen, straight-chain or branched-chain alkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, straight-chain or branched-chain hydroxyalkyl groups having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, isopropyl, hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxyisopropyl, R 7 identical or different and each independently selected from hydrogen, a straight-chain or branched alkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, a straight-chain or branched hydroxyalkyl group having 1 to 6, preferably 1 to 4, more preferably 1, 2 or 3 carbon atoms, (CH2CH2O) u H, (CH2CH2CH2O) v H and (CH2CH(CH3)CH2O) w H, most preferably methyl, ethyl, propyl, isopropyl, and wherein u = 1 to 14, preferably 1 to 6 v = 1 to 14, preferably 1 to 6 w = 1 to 14, preferably 1 to 6 a = 0, 1 or 2 b = 0, 1 or 2 a + b = 2 c = 0, 1 or 2, preferably 0 or 1, more preferably 0 d = 0, 1 or 2, preferably 1 or 2, more preferably 2 c + d = 2, - And their mixtures.

6. The method according to any one of claims 2 to 5,[[]] It is characterized in that The phase transfer catalyst is a quaternary ammonium salt having a general formula structure R1R2R3R4NX, wherein R1, R2, R3 and R4 are the same or different and are hydrocarbon groups selected from alkyl, aryl and aralkyl, and X is selected from halide ions, preferably chloride ions and / or bromide ions, hydrogen sulfate, alkyl sulfate, preferably methyl sulfate and ethyl sulfate, carbonate, bicarbonate, carboxylate, preferably acetate, or hydroxide.

7. The method according to claim 6,[[]] Characterized in that,[[]] - R1 and R2 are the same or different and are alkyl groups having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, especially preferably 1 to 5, most preferably 1 to 4 carbon atoms, wherein the alkyl group can be straight-chain, branched-chain, cyclic, saturated or unsaturated, most preferably straight-chain saturated alkyl,[[]] - R3 is selected from alkyl groups having 1 to 12, preferably 1 to 10, more preferably 1 to 7, even more preferably 1 to 6, especially preferably 1 to 5, most preferably 1 to 4 carbon atoms, aryl groups having 6 to 14, preferably 6 to 12, most preferably 6 to 10 carbon atoms, and aralkyl groups having 7 to 14, preferably 7 to 12, most preferably 7 to 10 carbon atoms, wherein the alkyl group can be straight-chain, branched-chain, cyclic, saturated or unsaturated, most preferably straight-chain, and - R4 is selected from alkyl groups having 3 to 12, preferably 3 to 10, more preferably 3 to 7, most preferably 4 to 6 carbon atoms, aryl groups having 6 to 14, preferably 6 to 12, most preferably 6 to 10 carbon atoms, and aralkyl groups having 7 to 14, preferably 7 to 12, most preferably 7 to 10 carbon atoms, wherein the alkyl group can be straight-chain, branched-chain, cyclic, saturated or unsaturated, most preferably straight-chain saturated, and - X is selected from halide ions, preferably chloride ions and / or bromide ions, hydrogen sulfate, alkyl sulfate, preferably methyl sulfate and ethyl sulfate, carbonate, bicarbonate, acetate or hydroxide.

8. The method according to claim 6 or 7,[[]] Characterized in that,[[]] R1 to R4 are selected such that the total number of carbon atoms in the quaternary ammonium cation is 6 to 14, preferably 7 to 14, more preferably 8 to 13 or R1 to R4 are selected such that the total number of carbon atoms in the quaternary ammonium cation is from 15 to 30, preferably from 15 to 28, more preferably from 15 to 24, even more preferably from 16 to 22, and most preferably from 16 to 20.

9. The method according to claim 6 or 7, characterized in that R1 to R4 and X are selected such that the total number of carbon atoms in the quaternary ammonium salt is from 6 to 14, preferably from 7 to 14, more preferably from 8 to 13, or R1 to R4 and X are selected such that the total number of carbon atoms in the quaternary ammonium salt is from 15 to 30, preferably from 15 to 28, more preferably from 15 to 24, even more preferably from 16 to 22, and most preferably from 16 to 20.

10. The method according to any one of claims 1 to 9, It is characterized in that wherein the polyisocyanurate is produced by reacting a) a polyester polyol or a mixture of polyester polyols or a mixture of a polyester polyol and a polyether polyol, which contains isocyanate-reactive groups selected from OH groups, SH groups, NH groups, NH2 groups and mixtures thereof, preferably OH groups, with b) an excess of one or more isocyanates selected from organic isocyanates, mixtures of organic isocyanates, organic polyisocyanates, mixtures of organic polyisocyanates, and mixtures of organic isocyanates and organic polyisocyanates, in the presence of c) a catalyst that catalyzes the reaction of the isocyanate-reactive groups with the isocyanate groups and / or the reaction of the isocyanate groups with each other, provided that it contains at least one trimerization catalyst d) optionally, a foam stabilizer e) optionally, a blowing agent f) optionally, other additives.

11. The method according to any one of claims 1 to 10, It is characterized in that wherein the polyester polyol is produced by reacting one or more aromatic or aliphatic carboxylic acids or a mixture of aromatic and aliphatic carboxylic acids, wherein each molecule of the carboxylic acid has 2 or 3, more preferably 2 carboxylic acid groups and has 2 to 12, preferably 4 to 10, more preferably 6 to 10 carbon atoms, with a polyol or a mixture of polyols, wherein at least one polyol has 2 or more isocyanate-reactive groups selected from OH groups, SH groups, NH groups, NH2 groups and mixtures thereof, preferably OH groups, and wherein the polyol or the mixture of polyols has a total of on average 1.8 to 8, preferably 1.9 to 5, more preferably 2 to 3, most preferably 2 of the isocyanate-reactive groups, and wherein the polyol has on average 2 to 12, preferably 2 to 10, more preferably 2 to 6 carbon atoms, and wherein the polyol can contain ether and / or carbonate functional groups, preferably a polyether polyol or a polyether carbonate polyol.

12. The method according to claim 11, characterized in that the aromatic carboxylic acid is selected from phthalic acid, preferably (o)-phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalenedicarboxylic acids and / or the aliphatic carboxylic acid is selected from succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid and fumaric acid.

13. The method according to any one of claims 1 to 12, It is characterized in that At least 90% by weight, preferably at least 95% by weight, more preferably at least 98% by weight of the polyol component used for preparing the polyisocyanurate is a polyester polyol having a hydroxyl value of 100 to 450 mg KOH / g, preferably 120 to 400 mg KOH / g, more preferably 140 to 350 mg KOH / g.

14. The method according to any one of claims 1 to 13, characterized in that the organic isocyanate and / or polyisocyanate is selected from monomers, oligomers or polymers, aliphatic, cycloaliphatic, arylaliphatic or aromatic isocyanates having 2 or more, preferably 2 to 4 isocyanate groups and mixtures thereof.

15. The method according to claim 14, characterized in that the polyisocyanurate has an isocyanate index equal to or greater than 150, preferably > 180, more preferably > 250, most preferably > 250 to 500.

16. The method according to any one of claims 1 to 15, characterized in that the one or more carboxylic acids obtained after hydrolysis are selected from phthalic acid, preferably (o)-phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalenedicarboxylic acids, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid and mixtures thereof and / or the one or more polyols obtained after hydrolysis are diols having a molecular weight lower than 180 g / mol, preferably lower than 140 g / mol, based on diols and / or diol ethers, particularly preferably monoethylene glycol and / or diethylene glycol, and / or the one or more organic amines and / or polyamines obtained after hydrolysis are selected from dodecane 1,12-diamine, 2-ethyltetramethylene 1,4-diamine, 2-methylpentamethylene 1,5-diamine, tetramethylene 1,4-diamine, pentamethylenediamine (PDA) and preferably hexamethylene 1,6-diamine (HMDA), cycloaliphatic diamines such as cyclohexane 1,3- and 1,4-diamine and any mixtures of these isomers, 4,4'-methylenebiscyclohexyl diisocyanate (H12MDI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (abbreviated as isophoronediamine or IPDA), hexahydrotolylene 2,4- and 2,6-diamine and corresponding isomer mixtures, and preferably aromatic diamines and polyisocyanates, such as toluene 2,4- and 2,6-diamine (TDA) and corresponding isomer mixtures, naphthalenediamine, diethyltoluenediamine, diphenylmethane 4,4'-, 2,4'- and 2,2'-diamine (MDA) and mixtures of polyphenylpolymethylene polyamines and their higher condensation analogues having an average functionality of 2 to 4.

17. The method according to any one of claims 1 to 16, characterized in that the reaction products of the hydrolysis are separated from each other and optionally purified, and the preferred separation and purification methods are selected from filtration, membrane separation, phase separation, chromatography, distillation, extraction and combinations of these methods.

18. The method according to any one of claims 1 to 17, It is characterized in that The polyisocyanurate is foamed, preferably a rigid foam.

19. The method according to any one of claims 1 to 18, Characterized in that, wherein the polyisocyanurate is contacted with water and the organic amine base, or with water, the organic amine base and the phase transfer catalyst, at a temperature of from 80°C to 220°C, preferably from 100°C to 200°C, more preferably from 120°C to 190°C, most preferably from 140°C to 180°C and / or for a period of from 1 minute to 48 hours, preferably from 1 minute to 40 hours, more preferably from 5 minutes to 35 hours, even more preferably from 10 minutes to 30 hours, particularly preferably from 20 minutes to 24 hours, especially preferably from 30 minutes to 18 hours, most preferably from 30 minutes to 16 hours and / or at atmospheric pressure or at a pressure of from 1 to 30 bar, from 2 to 20 bar, more preferably from 3 to 15 bar.

20. The method according to any one of claims 2 to 19, It is characterized in that wherein, based on the weight of the polyisocyanurate, at least 0.5% by weight of a catalyst is used, more preferably from 0.5 to 15% by weight, even more preferably from 1 to 10% by weight, particularly preferably from 1 to 8% by weight, especially preferably from 1 to 7% by weight, most preferably from 2 to 6% by weight.

21. The method according to any one of claims 1 to 20, Characterized in that, wherein the weight ratio of the sum of the organic amine bases to the polyisocyanurate is from 1:100 to 50:1, preferably from 1:50 to 25:1, more preferably from 1:10 to 20:1, even more preferably from 1:5 to 10:1, most preferably from 1:2 to 3:

1.

22. The method according to any one of claims 1 to 21, wherein, the hydrolysis results in a splitting rate of the isocyanurate groups present of greater than 85%, preferably greater than 90%, particularly preferably greater than 95%, even more preferably 100%.

23. Use of one or more carboxylic acids and / or polyols and / or organic amines and / or polyamines obtainable by the method according to any one of claims 1 to 22 in the production of new chemicals, preferably polyurethanes, preferably polyurethane foams, or polyisocyanurates, preferably polyisocyanurate foams.