Stabilisers for polyurethane foams containing recycled polyol

Abstract

The invention relates to a composition for the production of polyurethane foam, comprising (A) a polyol component which comprises at least one recycled polyol, (B) a polyisocyanate component, (C) at least one catalyst which catalyses the isocyanate-polyol, isocyanate-water and / or isocyanate trimerisation reactions, (D) at least one foam stabiliser, and (E) at least one chemical and / or physical blowing agent, wherein the at least one foam stabiliser is selected from the group of polyethersiloxanes of the general average composition according to formula 1, MaMb1DcDd1 (formula 1).

Description

[0001] Stabilizers for polyurethane foams containing recycled polyol

[0002] The present invention is in the field of polyurethanes. In particular, it relates to a process for producing polyurethane foams, preferably rigid polyurethane foams, using recycled polyols. Furthermore, it relates to the use of suitable additives and the application of these polyurethane foams.

[0003] The terms polyurethane and polyurethane foam are established technical terms and have long been known to those skilled in the art. For the purposes of the present invention, polyurethane (PU) is understood in particular to mean a product obtainable by reacting a polyisocyanate component with a polyol component. In addition to the polyurethane, other functional groups, such as uretdiones, carbodiimides, isocyanurates, allophanates, biurets, ureas, and / or uretimines, can also be formed. Therefore, polyurethane (PU) for the purposes of the present invention includes both polyurethanes and polyisocyanurates, polyureas, and polyisocyanate reaction products containing uretdione, carbodiimide, allophanate, biuret, and / or uretimine groups.Accordingly, polyurethane foam (PU foam) in the context of the present invention refers to a foam obtained as a reaction product of a polyisocyanate component and a polyol component. In addition to the eponymous polyurethane, other functional groups such as allophanates, biurets, ureas, carbodiimides, uretdiones, isocyanurates, and / or uretimines can also be formed.

[0004] Foams and PU foams are well known. Rigid PU foam is a well-established technical term. The known and fundamental difference between flexible and rigid foam is that flexible foam exhibits elastic behavior and, consequently, deformation is reversible. Rigid foam, on the other hand, is permanently deformed. Further information on rigid polyurethane foams can be found in "Kunststoffhandbuch, Volume 7, Polyurethane," Carl Hanser Verlag, 3rd edition 1993, Chapter 6. The terms "foam" and "foam" are used synonymously for the purposes of this invention. This also applies to related terms such as rigid foam or rigid foam, PU foam or PU foam, etc.

[0005] In the context of the supply of PU foams, especially rigid PU foams, it is particularly important to manufacture them from particularly sustainable materials and to contribute to a functioning circular economy in the field of polyurethane foams. This can be achieved, for example, through the use of recycled polyols obtained through chemical recycling, i.e., depolymerization of polyurethane, especially polyurethane foam and particularly preferably rigid polyurethane foam. Possibilities for producing such recycling polyols are known and are described in detail in WO 2018 / 091575 A1, CN 114106281 A, US 3441616 A, EP 0105167 A1, DD 226575 A1, US 5274004 A, DE 4217024 A1, DE 4234335 A1, DE 4442379 A1, EP 718349 A1, DE 19510638 A1, DE 19622761 A1, US 5763692 A, WO 2022063764 A1, WO 2015027319 A1, CN 105399985 A, WO 2020080619 A, WO 2019219814 A, WO 2021023889 A1 and WO 2022135987 A1.Processes such as glycolysis, alcoholysis, acidolysis, aminolysis, hydrolysis, or solvolysis can be used.

[0006] Recycled polyols can preferably be produced from production waste obtained during polyurethane foam production, such as cutting residues, sawing waste or material that does not pass quality control, but also from polyurethane foam waste, so-called waste foams, that have reached the end of their service life, such as foams from used refrigerators, used insulation materials or insulation boards, used sealing foams, used mattresses, used furniture, used sound absorption materials, used packaging foams or used vehicles.

[0007] However, the use of high proportions of such recycled polyols has so far often led to a deterioration in foam quality and therefore generally significantly limits the amount of recycled polyols used in polyurethane foam.

[0008] In the production of polyurethane foams, especially corresponding rigid foams, cell-stabilizing or foam-stabilizing additives (so-called foam stabilizers) are commonly used. These are intended to ensure a fine-cell, uniform, and low-interference foam structure, thus significantly influencing the performance properties, such as the thermal insulation capacity of the rigid foam. Surfactants based on polyether-modified siloxanes are particularly effective in this regard, and are therefore the preferred type of foam stabilizer. These so-called polyethersiloxane foam stabilizers (PES) are sufficiently known from the prior art and are described in detail, for example, in CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008 / 0125503, US 2015 / 0057384, EP 1520870 A1, EP 1211279, EP 0867464, EP 0867465 and EP 0275563.

[0009] Against this background, the object of the present invention was to enable the provision of polyurethane foams containing recycled polyols and possessing particularly advantageous performance properties, such as, in particular, low thermal conductivity and / or good surface quality. Within the scope of the present invention, it was surprisingly found that this is made possible by the inventive use of certain polyethersiloxane foam stabilizers, as specified in claim 1.

[0010] The object is achieved by the subject matter of the invention. The subject matter of the invention is a composition for producing polyurethane foam, preferably rigid polyurethane foam, comprising

[0011] (A) a polyol component comprising at least one recycled polyol,

[0012] (B) a polyisocyanate component,

[0013] (C) at least one catalyst which catalyzes the isocyanate-polyol and / or isocyanate-water and / or isocyanate trimerization reactions,

[0014] (D) at least one foam stabilizer,

[0015] (E) at least one chemical and / or physical blowing agent, wherein the at least one foam stabilizer is selected from the group of polyether siloxanes of the general average composition according to formula 1,

[0016] MaMb 1 DcDd 1 (Formula 1) a = 0 to 2, particularly preferably 0 to 0.5, b = 0 to 2, particularly preferably 1.5 to 2, c = 8 to 150, preferably 18 to 100, particularly preferably 18 to 70, d = 0 to 20, preferably 1 to 16, particularly preferably 1 to 13, where a + b = 2, and for b = 0, d > 1 and for d = 0, b = 1.5 to 2,

[0017] R = each independently of one another, identical or different alkyl radicals having 1 to 16 carbon atoms, identical or different aryl radicals having 6 to 16 carbon atoms, -H or -OR 2 , preferably methyl, ethyl, phenyl or H, especially methyl,

[0018] R 2 = each independently of one another identical or different alkyl radicals having 1 to 16 carbon atoms, identical or different aryl radicals having 6 to 16 carbon atoms or H,

[0019] R 1 = each independently of one another identical or different polyether radicals, preferably identical or different polyether radicals with a general average composition according to formula 2, — R 3 — O-■CH2CH2O CH2CH(CH3)O CH(CH3)CH2O CR2 4 CR2 4 OR 5 el J f l J gl J h

[0020] (Formula 2)

[0021] R 3= each independently of one another identical or different divalent alkyl radicals having 2 to 15 carbon atoms, preferably identical or different divalent alkyl radicals having 3 to 6 carbon atoms, particularly preferably -(CH2)3-

[0022] R 4 = each independently of one another, identical or different alkyl radicals having 1 to 18 carbon atoms, which optionally have ether functions, or identical or different aryl radicals having 6 to 18 carbon atoms, which optionally have ether functions, or H, preferably H, ethyl or benzyl,

[0023] R 5 = each independently of one another identical or different residues selected from the group consisting of R 2 and C(O)R 2, where methyl, butyl, -H or C(O)Me are preferred, e = 0 to 100, preferably 0 to 80, in particular 0 to 50, f = 0 to 100, preferably 0 to 80, in particular 0 to 50, g = 0 to 100, preferably 0 to 80, in particular 0 to 50, h = 0 to 100, preferably 0 to 40, particularly preferably 0, where e + f + g + h > 0, where it is very particularly preferred if at least one of the polyether radicals R 1 corresponds to at least one of the following categories 1 or 2

[0024] Category 1 , based on formula 2: e = 8 to 16, f = g = h = O, or e + f + g = 15 to 34,

[0025] (f + g) / (e + f + g) > 0 to 0.25, particularly preferably 0.1 to 0.2, h = 0,

[0026] Category 2, based on formula 2: e + f + g = 7 to 15,

[0027] (f + g) / (e + f + g) > 0.15 to 0.8, h = 0, or e + f + g = 13 to 32,

[0028] (f + g) / (e + f + g) > 0.25 to 0.8, particularly preferably 0.3 to 0.4, h = 0 and wherein polyether siloxanes according to formula 1 are used in a total amount of 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, particularly preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total polyol component. The polyether siloxanes usable according to the invention, as characterized in particular in one of the patent claims, can be obtained by the customary routes known to the person skilled in the art, for example by the known reaction of allyl polyethers and SiH-functional siloxanes using Pt catalysts. This is demonstrated in the experimental section using several examples.

[0029] The subject matter of the invention is associated with numerous advantages. It enables the provision of PU foams that offer significant advantages in terms of sustainability while still meeting known requirements. The PU foams are advantageously dimensionally stable, hydrolysis-stable, have very good insulation properties, and exhibit a high surface quality. This is advantageously achieved without compromising the other properties of the material. With regard to the provision of rigid PU foams, particularly fine-cell, uniform, and low-defect foam structures are also possible.

[0030] It corresponds to a particularly preferred embodiment of the invention if the composition according to the invention contains at least one polyethersiloxane of the formula (1), which is characterized in that at least one of the polyethers R contained in the polyethersiloxane in question 1 satisfies the above-mentioned category 1, whereby it corresponds to a particularly preferred variant of category 1 if e = 8 to 16 and f = g = h = 0.

[0031] If the composition according to the invention contains at least one polyethersiloxane according to formula

[0032] (1) which contains at least two polyethers of the general formula (2), wherein at least one of these polyethers must satisfy the abovementioned category 1 and at least one of these polyethers must satisfy the abovementioned category 2 and the preferred ratio of polyethers of category 1 and polyethers of category 2 in the polyethersiloxane in question corresponds to 10:90 to 90:10 wt.%, particularly preferably 20:80 to 80:20 wt.%, in particular 30:70 to 70:30 wt.%, then there is a further particularly preferred embodiment of the invention.

[0033] A further particularly preferred embodiment of the invention is present when the composition according to the invention is characterized in that at least two polyethersiloxanes according to formula (1) are contained, wherein at least one of these polyethersiloxanes contains at least one polyether of the general formula (2) which satisfies the above-mentioned category 1 and at least one of these polyethersiloxanes contains at least one polyether of the general formula

[0034] (2) which satisfies the above-mentioned category 2 and wherein the preferred ratio of polyether siloxanes of the formula (1) containing at least one polyether of category 1 and polyether siloxanes of the formula (1) containing at least one polyether of category 2 is 10:90 to 90:10 wt. %, particularly preferably 20:80 to 80:20 wt. %, in particular 30:70 to 70:30 wt. %. If a composition according to the invention is characterized in that the at least one recycled polyol is used in a total amount of at least 30 parts by weight, preferably more than 50 parts by weight, particularly preferably more than 70 parts by weight, based on 100 parts by weight of the total polyol component, then a further particularly preferred embodiment of the invention is present.

[0035] Again, a further particularly preferred embodiment of the invention is present when the composition according to the invention is characterized in that the at least one recycled polyol used was obtained by depolymerization of polyurethane, preferably depolymerization of polyurethane by hydrolysis, solvolysis, aminolysis, acidolysis, alcoholysis or glycolysis, preferably glycolysis, hydrolysis, or aminolysis, particularly preferably glycolysis, it also being possible to use different recycled polyols from different depolymerization processes.

[0036] If the composition according to the invention is characterized in that the at least one recycled polyol used is obtained by depolymerization of polyurethane foam, preferably rigid polyurethane foam, particularly preferably rigid polyurethane foam containing polyether and / or polyester polyol, by a process mentioned in claim 6, particularly preferably glycolysis, then this also constitutes a further particularly preferred embodiment of the invention.

[0037] The at least one recycled polyol is preferably selected from the group consisting of recycled polyether polyols and recycled polyester polyols. Polyether polyols and polyester polyols are well known to those skilled in the art, and their known reaction with polyisocyanates enables the well-proven production of polyurethanes.

[0038] A further particularly preferred embodiment of the invention is when the composition according to the invention is characterized in that the recycled polyol used is obtained from a PU waste foam.

[0039] A PU waste foam is in particular a PU foam which

[0040] (i) results from production waste obtained during polyurethane foam production, such as cutting residues, sawing waste or material that does not pass quality control, and / or

[0041] (ii) results from PU foams that have reached the end of their service life, such as foams from used refrigerators, used insulation materials or insulation boards, used sealing foams, used mattresses, used furniture, used sound absorption materials, used packaging foams or foams from used vehicles.

[0042] A composition according to the invention which acts as a propellant

[0043] (i) one or more hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclo-, iso- and / or n-pentane, and / or

[0044] (ii) one or more hydrofluoroolefins and / or hydrohaloolefins, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) and / or 1336mzz, and necessarily water, also corresponds to a further particularly preferred embodiment of the invention.

[0045] A preferred PU foam formulation, in particular PU rigid foam formulation, within the meaning of this invention has the composition stated in Table 1.

[0046] Table 1 : Composition of a preferred PU foam formulation

[0047] A further subject of the present invention is a process for producing PU foam, preferably rigid polyurethane foam, based on a reaction mixture containing a composition according to the invention as described above, in particular as defined in one of claims 1 to 9.

[0048] The inventive process for producing PU foam, preferably rigid polyurethane foam, can be carried out by any known method, e.g., by hand mixing or, preferably, using foaming machines. If the process is carried out using foaming machines, high-pressure or low-pressure machines can be used. The inventive process can be carried out both batchwise and continuously, and 1K, 1.5K, or 2K systems, as described in EP 3717538 A1, US 7776934 B2, EP 1400547 B1, or EP 2780384 B2, can be used.

[0049] For further preferred embodiments and configurations of the process according to the invention, reference is also made to the statements already made in connection with the composition according to the invention.

[0050] A further subject matter of the present invention is a PU foam, in particular a PU rigid foam, produced according to the above-mentioned process according to the invention, in particular using a composition according to the invention.

[0051] If the PU foam according to the invention, in particular PU rigid foam, has a density of 5 to 900 kg / m 3 , preferably 5 to 350 kg / m 3 , especially 8 to 200 kg / m 3 This is a preferred embodiment of the invention.

[0052] A further subject matter of the present invention relates to the use of PU foam according to the invention, in particular PU rigid foam, as an insulating material and / or as a construction material, in particular in construction applications, in particular in spray foam and / or 1- & 1.5-component canned foam or in the refrigeration sector, as a sound absorption material, as packaging foam, as wood imitation, as model foam, as headliner for automobiles, as automobile interior paneling, as sealing foam or pipe sheathing for tubes.

[0053] A preferred composition according to the invention contains the following components:

[0054] A) Polyol component comprising at least one recycled polyol

[0055] B) Polyisocyanate component

[0056] C) Catalyst that catalyzes the reactions isocyanate-polyol and / or isocyanate-water and / or isocyanate trimerization,

[0057] D) Foam stabilizer

[0058] E) Propellant

[0059] F) optionally further additives, preferably fillers, liquid flame retardants, etc.

[0060] The polyol component (A) consists of at least one polyol and optionally at least one organic compound containing at least two isocyanate-reactive groups, preferably selected from the group consisting of OH, NH, and NH2 groups. Polyols are organic compounds containing multiple hydroxyl groups (-OH).

[0061] If one of the aforementioned organic compounds of the polyol component contains at least two OH groups, then it is exclusively classified as a polyol for the purposes of the invention. This means that if an organic compound of the polyol component could be considered both a polyol and an organic compound containing at least two isocyanate-reactive groups selected from the group consisting of OH, NH, and NH2 groups, then it is exclusively classified as a polyol for the purposes of the invention.

[0062] Based on its total weight, the polyol component preferably contains at least 50 wt.% of polyols which contain only hydroxyl groups (-OH) as isocyanate-reactive groups.

[0063] Based on the total number of isocyanate-reactive groups in the polyol component, it is preferred that at least 50% of these are hydroxyl groups (-OH).

[0064] Corresponding compounds that can typically be used in the production of PU foams are known to those skilled in the art and are described, for example, in "Kunststoffhandbuch, Volume 7, Polyurethane," Carl Hanser Verlag, 3rd edition 1993, Chapter 3.1. Compounds with OH numbers in the range of 10 to 1200 mg KOH / g are typically used.

[0065] Particularly preferred compounds are all polyether polyols and / or polyester polyols commonly used for the production of polyurethane systems, in particular polyurethane foams. Polyether polyols can be obtained, for example, by reacting polyhydric alcohols or amines with alkylene oxides. Polyester polyols that can be used with preference are usually based on esters of polybasic carboxylic acids (which can be either aliphatic, for example, adipic acid, or aromatic, for example, phthalic acid or terephthalic acid) with polyhydric alcohols (usually glycols). In addition, polyether polycarbonate polyols, natural oil-based polyols (NOPs; described in WO 2005 / 033167, US 2006 / 0293400, WO 2006 / 094227, WO 2004 / 096882, US 2002 / 0103091, WO 2006 / 116456, EP 1678232), filler polyols, and / or prepolymer-based polyols can be used.

[0066] According to the invention, the recycling polyols already described above are used at least in part, ie the polyol component comprises at least one recycling polyol

[0067] The polyisocyanate component (B) consists of at least one polyisocyanate having two or more isocyanate groups. Suitable polyisocyanates for the purposes of this invention are all organic isocyanates having two or more isocyanate groups, in particular the known aliphatic, cycloaliphatic, arylaliphatic, and preferably aromatic polyfunctional isocyanates.

[0068] Examples which can be mentioned here are alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-ethyl-tetramethylene-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-diisocyanate and the corresponding isomer mixtures, 4,4'-methylenedicyclohexyl diisocyanate (H12MDI), isophorone diisocyanate (IPDI), 2,4- and 2,6-methylcyclohexyl diisocyanate and the corresponding isomer mixtures and preferably aromatic di- and polyisocyanates such as 2,4- and 2,6-Toluene diisocyanate (TDI) and the corresponding isomer mixtures, naphthylene diisocyanate, diethyltoluene diisocyanate, 4,4'- or 2,2'- or 2,4'-diphenylmethane diisocyanate (MDI) and polymethylene polyphenyl polyisocyanate (PMDI, “polymeric MDI”).The organic polyisocyanates can be used individually or in the form of mixtures. Corresponding "oligomers" of diisocyanates can also be used, such as the IPDI trimer based on isocyanurate, biuret, or urethdiones. Furthermore, the use of prepolymers based on the above-mentioned isocyanates is possible. Particularly suitable is the mixture known as "polymeric MDI" (also called "crude MDI"), consisting of MDI and more highly condensed analogues with an average functionality of 2 to 4, as well as the various isomers of TDI in pure form or as a mixture of isomers. It is also possible to use isocyanates modified by the incorporation of urethane, uretdione, isocyanurate, allophanate, and other groups, so-called modified isocyanates. Examples of particularly suitable isocyanates include:in EP 1712578, EP 1161474, WO 00 / 58383, US 2007 / 0072951 , EP 1678232 and WO 2005 / 085310, which are incorporated herein by reference.

[0069] A preferred ratio of isocyanate groups and isocyanate-reactive groups, expressed as an index of the formulation (isocyanate index), ie as a stoichiometric ratio of isocyanate groups to isocyanate-reactive groups (e.g. OH groups, NH groups) multiplied by 100, is in the range from 10 to 1000, preferably 40 to 400. An index of 100 represents a molar ratio of the reactive groups of 1 to 1.

[0070] Suitable catalysts (C) that can be used for the production of polyurethanes, in particular PU foams, are known to the person skilled in the art from the prior art. For the purposes of the present invention, in particular, all compounds capable of catalyzing the reaction of isocyanate groups with OH, NH, or other isocyanate-reactive groups and / or the reaction of isocyanate groups with one another can be used.

[0071] The usual catalysts known from the prior art can be used, such as amines (cyclic, acyclic; monoamines, diamines, oligomers with one or more amino groups), ammonium compounds, organometallic compounds and / or metal salts, preferably those of tin, iron, bismuth, potassium and / or zinc. In particular, mixtures of several such compounds can be used as catalysts.

[0072] Suitable amounts used depend on the type of catalyst and can, for example, in the case of amine catalysts, preferably be in the range of 0.05 to 5 pphp (= parts by weight based on 100 parts by weight of polyol component) or, for example, in the case of potassium salts, preferably be in the range of 0.1 to 10 pphp.

[0073] Foam stabilizers (D) and their use in the production of PU foams are known to the person skilled in the art as described above. According to the invention, at least one of the polyethersiloxane foam stabilizers according to the invention is used. In addition to the polyethersiloxane foam stabilizers according to the invention, further polyethersiloxane foam stabilizers as well as Si-free surfactants can also be used. For example, EP 2295485 A1 describes the use of lecithin and US 3746663 describes the use of vinylpyrrolidone-based structures. Further Si-free foam stabilizers are described, for example, in EP 2511328 B1, DE 1020011007479 A1, DE 3724716 C1, EP 0734404, EP 1985642, DE 2244350 and US 5236961.

[0074] Blowing agents (E) and their use in the production of PU foams are known to those skilled in the art. The use of blowing agents is optional; preferably, blowing agents are used. The use of one or a combination of several blowing agents depends fundamentally on the type of foaming process, the type of system, and the application of the resulting PU foam. Both chemical and / or physical blowing agents, or a combination of both, can be used. Depending on the amount of blowing agent used, a foam with a high or low density is produced. For example, foams with densities of 5 kg / m 3 up to 900 kg / m 3 , preferably 5 to 350 kg / m 3 , particularly preferably 8 to 200 kg / m 3 , especially 8 to 150 kg / m 3 be manufactured.

[0075] As optional physical blowing agents, one or more of the corresponding compounds with suitable boiling points, such as hydrocarbons with 3, 4 or 5 carbon atoms, preferably cyclo-, iso- or n-pentane, fluorocarbons (HFC), preferably HFC 245fa, HFC 134a or HFC 365mfc, chlorofluorocarbons (HCFC), preferably HCFC 141b, hydrofluoroolefins (HFO) or hydrohaloolefins, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) or 1336mzz, esters, preferably methyl formate, ketones, preferably acetone, ethers, preferably dimethoxymethane, or chlorinated hydrocarbons, preferably dichloromethane or 1,2-dichloroethane, and mixtures thereof can be used.

[0076] As optional chemical blowing agents, one or more compounds can be used that either react with NCO groups to release gases, such as water or formic acid, or release gases due to the temperature increase during the reaction, such as sodium bicarbonate.

[0077] It corresponds to a particularly preferred embodiment if the composition according to the invention contains water as a blowing agent in combination with hydrocarbons having 5 carbon atoms, HFO, hydrohaloolefins or HFC or mixtures thereof.

[0078] As optional further additives (F), one or more of the substances known from the prior art which are used in the production of polyurethanes, in particular PU foams, such as crosslinkers, chain extenders, stabilizers against oxidative degradation (so-called antioxidants), flame retardants, biocides, cell-refining additives, nucleating agents, cell openers, solid fillers, antistatic additives, thickeners, dyes, pigments, color pastes, fragrances and / or emulsifiers, etc., can be used.

[0079] As an optional flame retardant, the composition according to the invention can contain one or more of the known flame retardants suitable for the production of PU foams, such as, for example, halogen-containing or halogen-free organic phosphorus-containing compounds, such as triethyl phosphate (TEP), tris(1-chloro-2-propyl) phosphate (TCPP), tris(2-chloroethyl) phosphate (TCEP), dimethyl methanephosphonate (DMMP), dimethylpropanephosphonate (DMPP), ammonium polyphosphate or red phosphorus, nitrogen-containing compounds, such as, for example, melamine, melamine cyanurate or melamine polyphosphate, or halogenated compounds. Mixtures of different flame retardants can also be used. Unless otherwise stated in this description, any preferred or particularly preferred embodiment of the invention can be combined with one or more of the other preferred or particularly preferred embodiments of the invention.

[0080] The subject matters according to the invention are described below by way of example, without the invention, the scope of which emerges from the entire description and the claims, being intended to be limited to these exemplary embodiments. If ranges, general formulas or classes of compounds are specified, these are intended to include not only the corresponding ranges or groups of compounds that are explicitly mentioned, but also all sub-ranges and sub-groups of compounds that can be obtained by removing individual values ​​(ranges) or compounds. If documents are cited within the scope of this description, their content, particularly with regard to the facts in connection with which the document was cited, is intended to be fully incorporated into the disclosure of the present invention. Percentages are, unless otherwise stated, percentages by weight.Unless otherwise stated, mean values ​​are numerical averages. Unless otherwise stated, parameters determined by measurement are stated at a temperature of 23 °C and atmospheric pressure.

[0081] Examples:

[0082] Synthesis of polyethersiloxane foam stabilizers (PES)

[0083] A xylene solution of the Karstedt catalyst (platinum(O)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (CAS 68478-92-2)) was used as the Pt catalyst for the preparation of the polyethersiloxanes. The Pt content of the solution was 2 wt%. The catalyst was purchased from Merck and used without further processing.

[0084] To synthesize the polyethersiloxanes, allyl polyether and SiH-functional siloxane according to the composition given in Table 2 were placed in a three-necked flask equipped with a precision glass stirrer and reflux condenser. The ratio of allyl polyether to SiH-functional siloxane was chosen such that 1.4 mol of double bonds from the allyl polyether were present per mol of SiH functions. The apparatus was inertized with nitrogen, and the mixture was heated to 80 °C. Then, 10 ppm of Pt, based on the total weight, was added in the form of the Pt catalyst described above. An exothermic reaction began. The temperature was kept below 110 °C by cooling. The reaction mixture was then stirred at 100 °C for 3 h. Clear to slightly cloudy products were consistently obtained.

[0085] PES 14 and PES 15 were prepared by mixing the respective foam stabilizers in a weight ratio of 1:1.

[0086] The polyether siloxanes shown in Table 2 according to Formula 1 and Formula 2 were prepared and subjected to application-related tests. For PES 1 to 15, R = methyl, R 3 = -(CH2)3- and h = 0. PES 1 to 3 are considered non-inventive comparative examples.

[0087] Table 2: Composition of polyethersiloxane foam stabilizers (PES) comparative example not according to the invention

[0088] Recycling polyol 1 was produced by glycolysis according to a specification from H&S Anlagentechnik from 2012: https: / / www.dbu.de / OPAC / ab / DBU-Abschlussbericht-AZ-29395.pdf.

[0089] For this purpose, a reactor from Parr (Parr Instrumental Company) was equipped with a glass

[0090] Inner container and a mechanical stirrer with 294.0 g of compressed PU foam pieces (approx.

[0091] 1 cm x 1 cm). The polyurethane foam used for the glycolysis was produced as described below according to recipe A from Table 3 using TEGOSTAB® B 8462 from Evonik Operations GmbH as foam stabilizer. Then, 152.3 g of the polyol Daltolac® R 471, 75.1 g of phthalic acid and 11.6 g of aqueous hydrogen peroxide solution (30 wt. % in water) were added to the foam pieces. The reaction mixture was heated to 250 °C and kept within a temperature range of 237 °C to 256 °C for 5 h. After the reaction time, the heating was turned off and when a reaction temperature of 160 °C was reached, a second portion of 144.6 g of Daltolac® R 471 was added under a counterflow of nitrogen. The liquid reaction mixture was cooled to room temperature and, after decanting, used as recycling polyol 1.The recycling process was repeated to provide a sufficient amount of recycled polyol for the foaming experiments. Recycling polyol 2 was produced analogously to recycling polyol 1. Instead of freshly produced foam, foam pieces from used PU insulation boards based on polyether polyols were used.

[0092] The formulations shown in Table 3 were used for the application-related comparison. The comparative foamings were carried out using a hand-mixing method. Polyol, catalysts, water, foam stabilizer, blowing agent, and any other additives were weighed into a beaker and mixed using a 6 cm diameter plate stirrer for 30 seconds at 1000 rpm. The amount of blowing agent evaporated during the mixing process was determined by reweighing and then replenished. The MDI was then added, and the reaction mixture was stirred using the described stirrer for 5 seconds at 3000 rpm. The mold was then immediately transferred to a 145 cm x 14 cm x 3.5 cm aluminum mold thermostatted to 45 °C, tilted at an angle of 10° (along the 145 cm side), and lined with polyethylene film.The foam formulation was introduced on the lower side so that the expanding foam fills the mold in the pouring area and rises towards the higher side.

[0093] To determine the flow behavior, the amount of foam formulation used was calculated so that it was approximately 10% below the amount required for minimum filling of the mold (approx. 260 g). After 10 minutes, the foams were demolded and the mean length of the test specimen was determined. The reduced length is then determined as the quotient of the product of the mean length of the test specimen, the measured air pressure and the mean value of the weights of all tested specimens, as well as the product of standard air pressure (1013.25 hPa) and the weight of the test specimen. The flow difference given in Tables 4-8 is expressed as the percentage difference between the reduced length of the test specimen and a reference specimen produced with PES 1 as the foam stabilizer and the respective formulation.

[0094] To determine all other properties, the amount of foam formulation used for a second test specimen was calculated so that it was approximately 10% higher than the amount required for minimum mold filling. After 10 minutes, the foams were demolded. One day after foaming, the foam properties were analyzed. Surface quality and internal defects were assessed subjectively using a scale of 1 to 10, with 10 representing an (idealized) undisturbed foam and 1 representing extremely severely disturbed foam. The thermal conductivity (A-value in mW / m K) was measured on 2.5 cm thick panes using a Hesto Lambda Control device, model HLC X206, at an average temperature of 10 °C in accordance with the specifications of standard EN12667:2001.

[0095] The results are summarized in Tables 4-8. Table 3: PU formulations. Quantities in parts by weight.

[0096] *Daltolac® R 471 from Huntsman, OH number 470 mg KOH / g **Amine catalysts from Evonik Operations GmbH ***Polymeric MDI, 200 mPa s, 31.5% NCO, functionality 2.7.

[0097] Table 4: Foam properties for foams of formulation A Comparative example not according to the invention Table 5: Foam properties for foams of formulation B Comparative example not according to the invention Table 6: Foam properties for foams of formulation C Comparative example not according to the invention Table 7: Foam properties for foams of formulation D Comparative example not according to the invention Table 8: Foam properties for foams of formulation E comparative example not according to the invention

[0098] For formulations C and E with higher recycled polyol content, the foam stabilizers that demonstrated the most promising results in formulations B and D were selected. The results show that the non-inventive foam stabilizers, when used with a recycled polyol in formulations B to E, lead to a significantly poorer property profile, characterized in particular by higher thermal conductivity, poorer flow properties, and a poorer surface. With the foam stabilizers according to the invention, however, the property profile can be significantly improved, achieving performance comparable to formulations without recycled polyol.

Claims

Patent claims: 1 . Composition for producing polyurethane foam, preferably rigid polyurethane foam, comprising (A) a polyol component comprising at least one recycled polyol, (B) a polyisocyanate component, (C) at least one catalyst which catalyzes the isocyanate-polyol and / or isocyanate-water and / or isocyanate trimerization reactions, (D) at least one foam stabilizer, (E) at least one chemical and / or physical blowing agent, characterized in that the at least one foam stabilizer is selected from the group of polyether siloxanes of the general average composition according to formula 1, MaM b 1 DcDd 1 (Formula 1) a = 0 to 2, particularly preferably 0 to 0.5, b = 0 to 2, particularly preferably 1.5 to 2, c = 8 to 150, preferably 18 to 100, particularly preferably 18 to 70, d = 0 to 20, preferably 1 to 16, particularly preferably 1 to 13, where a + b = 2, and for b = 0, d > 1 and for d = 0, b = 1.5 to 2, R = each independently of one another, identical or different alkyl radicals having 1 to 16 carbon atoms, identical or different aryl radicals having 6 to 16 carbon atoms, -H or -OR 2 , preferably methyl, ethyl, phenyl or H, especially methyl, R 2 = each independently of one another, identical or different alkyl radicals having 1 to 16 carbon atoms, identical or different aryl radicals having 6 to 16 carbon atoms or H, R 1 = each independently of one another identical or different polyether residues, preferably identical or different polyether residues with a general average composition according to formula 2, (Formula 2) R 3 = each independently of one another identical or different divalent alkyl radicals having 2 to 15 carbon atoms, preferably identical or different divalent alkyl radicals having 3 to 6 carbon atoms, particularly preferably -(CH2)s-, R 4 = each independently of one another, identical or different alkyl radicals having 1 to 18 carbon atoms, which optionally have ether functions, or identical or different aryl radicals having 6 to 18 carbon atoms, which optionally have ether functions, or H, preferably H, ethyl or benzyl, R 5 = each independently of one another identical or different residues selected from the group consisting of R 2 and C(O)R 2, where methyl, butyl, -H or C(G)Me are preferred, e = 0 to 100, preferably 0 to 80, in particular 0 to 50, f = 0 to 100, preferably 0 to 80, in particular 0 to 50, g = 0 to 100, preferably 0 to 80, in particular 0 to 50, h = 0 to 100, preferably 0 to 40, particularly preferably 0, where e + f + g + h > 0, where it is very particularly preferred if at least one of the polyether radicals R 1 corresponds to at least one of the following categories 1 or 2 Category 1 , based on formula 2: e = 8 to 16, f = g = h = o, or e + f + g = 15 to 34, (f + g) / (e + f + g) > 0 to 0.25, particularly preferably 0.1 to 0.2, h = 0, Category 2, based on formula 2: e + f + g = 7 to 15, (f + g) / (e + f + g) > 0.15 to 0.8, h = 0, or e + f + g = 13 to 32, (f + g) / (e + f + g) > 0.25 to 0.8, particularly preferably 0.3 to 0.4, h = 0 and wherein polyether siloxanes according to formula 1 are used in a total amount of 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, particularly preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total polyol component.

2. Composition according to claim 1, characterized in that at least one polyethersiloxane of the formula (1) is present, which is characterized in that at least one of the polyethers R contained in the polyethersiloxane in question 1 satisfies Category 1, whereby it corresponds to a particularly preferred variant of Category 1 if e = 8 to 16 and f = g = h = 0.

3. Composition according to claim 1 or 2, characterized in that at least one polyether siloxane according to formula (1) is present, which contains at least two polyethers of the general formula (2), wherein at least one of these polyethers must satisfy category 1 and at least one of these polyethers must satisfy category 2 and the preferred ratio of polyethers of category 1 and polyethers of category 2 in the polyether siloxane in question corresponds to 10:90 to 90:10 wt.%, particularly preferably 20:80 to 80:20 wt.%, in particular 30:70 to 70:30 wt.%.

4. Composition according to one of claims 1 to 3, characterized in that at least two polyether siloxanes according to formula (1) are present, wherein at least one of these polyether siloxanes contains at least one polyether of the general formula (2) which satisfies category 1 and at least one of these polyether siloxanes contains at least one polyether of the general formula (2) which satisfies category 2 and wherein the preferred ratio of polyether siloxanes of the formula (1) containing at least one polyether of category 1 and polyether siloxanes of the formula (1) containing at least one polyether of category 2 is 10:90 to 90:10 wt.%, particularly preferably 20:80 to 80:20 wt.%, in particular 30:70 to 70:30 wt.%.

5. Composition according to one of claims 1 to 4, characterized in that the at least one recycled polyol is used in a total amount of at least 30 parts by weight, preferably more than 50 parts by weight, particularly preferably more than 70 parts by weight, based on 100 parts by weight of the total polyol component.

6. Composition according to one of claims 1 to 5, characterized in that the recycled polyol used was obtained by depolymerization of polyurethane, preferably depolymerization of polyurethane by hydrolysis, solvolysis, aminolysis, acidolysis, alcoholysis or glycolysis, preferably glycolysis, hydrolysis or aminolysis, particularly preferably glycolysis, it also being possible to use different recycled polyols from different depolymerization processes.

7. Composition according to one of claims 1 to 6, characterized in that the recycled polyol used is obtained by depolymerization of polyurethane foam, preferably rigid polyurethane foam, particularly preferably polyether and / or polyester Polyol-containing rigid polyurethane foam is obtained by a process mentioned in claim 6, particularly preferably glycolysis.

8. Composition according to one of claims 1 to 7, characterized in that the recycled polyol used is obtained from a PU waste foam.

9. Composition according to one of claims 1 to 8, characterized in that the composition contains as propellant (i) one or more hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclo-, iso- and / or n-pentane, and / or (ii) one or more hydrofluoroolefins and / or hydrohaloolefins, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) and / or 1336mzz, and necessarily water.

10. Process for producing PU foam, preferably rigid polyurethane foam, based on a reaction mixture containing a composition as defined in any one of claims 1 to 9.

11. PU foam, in particular PU rigid foam, produced according to the process of claim 10.

12. Use of PU foam, preferably PU rigid foam, according to claim 11 as insulating material and / or as construction material, in particular in building applications, in particular in spray foam and / or 1- & 1.5-component canned foam or in the refrigeration sector, as sound absorption material, as packaging foam, as wood imitation, as model foam, as headliner for automobiles, as automobile interior paneling, as sealing foam or pipe sheathing for tubes.

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