Stabilizer for polyurethane foams comprising recycled polyols

Abstract

The invention relates to a composition for producing polyurethane foams, said composition comprising (A) a polyol component comprising at least one recycled polyol, (B) a polyisocyanate component, (C) at least one catalyst that catalyzes isocyanate-polyol reactions, isocyanate-water reactions and / or isocyanate trimerization reactions, (D) at least one foam stabilizer, (E) at least one polyol component comprising at least one recycled polyol, (E) at least one polyol component comprising at least one recycled polyol, (E) at least one polyol component comprising at least one recycled polyol, (E) at least one polyol component comprising at least one recycled polyol, (E) at least one polyol component comprising at least one recycled polyol, (E) at least one polyol component comprising at least one recycled polyol. And (E) at least one chemical and / or physical blowing agent wherein the at least one foam stabilizer is selected from the group consisting of polyether siloxanes of general average composition according to Formula 1, MaMb1DcDd1 (Formula 1)

Description

Technical Field

[0001] The present invention belongs to the field of polyurethanes. In particular, the present invention relates to a method for preparing polyurethane foams, preferably rigid polyurethane foams, using recycled polyols. The present invention also relates to the use of suitable additives and to the use of these polyurethane foams. Background Art

[0002] The term "polyurethane" and "polyurethane foam" are long-established technical terms known to those skilled in the art. In the context of the present invention, polyurethane (PU) is particularly understood to mean the obtainable product by the reaction of polyisocyanate component and polyol component. Except polyurethane, other functional groups can also be formed in this reaction, such as uretdiones, carbodiimides, isocyanurates, allophanates, biuret, ureas and / or uretonimines. Therefore, for purposes of the present invention, polyurethane (PU) is understood to not only mean polyurethane, and means polyisocyanurate, polyurea and the polyisocyanate reaction products that comprise uretdiones, carbodiimide groups, allophanate groups, biuret groups and / or uretonimine groups. Therefore, in the context of the present invention, polyurethane foam (PU foam) is understood to mean the foam obtained as the reaction product of polyisocyanate component and polyol component. Besides the polyurethanes of the same name, further functional groups can also be formed here, examples being allophanates, biuret groups, ureas, carbodiimides, uretdiones, isocyanurates and / or uretonimines.

[0003] Foams and PU foams are known per se. Rigid PU foam is an established technical term. The known and fundamental difference between flexible foams and rigid foams is that flexible foams exhibit elastic properties and are therefore reversible in their deformation. In contrast, rigid foams deform permanently. Further details about rigid polyurethane foams can also be found in "Kunststoffhandbuch, Band 7, Polyurethane [Plastics Handbook, Volume 7, Polyurethanes]", Carl Hanser Verlag, 3rd Edition 1993, Chapter 6. In the context of the present invention, the terms "foam" and "foam material" are used synonymously. This also applies accordingly to compound terms based thereon, such as rigid foam or rigid foam material or PU foam or PU foam material, etc.

[0004] A particularly important concern in connection with the provision of PU foams, in particular rigid PU foams, is to produce them from particularly sustainable materials and to contribute to an effective circular economy in the field of polyurethane foams. This can be achieved, for example, by using recycled polyols obtained by chemical recycling, i.e., depolymerization, of polyurethanes, in particular polyurethane foams, particularly preferably rigid polyurethane foams. The possibility of preparing such recycled polyols is known and is described extensively in particular 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, DE19510638 A1, DE 19622761 A1, US 5763692 A, WO 2022063764 A1, WO 2015027319 A1, CN105399985 A, WO 2020080619 A, WO 2019219814 A, WO 2021023889A1 and WO 2022135987A1. Methods such as glycolysis, alcoholysis, acidolysis, aminolysis, hydrolysis or solvolysis can be used.

[0005] Recycled polyols can preferably be prepared from production waste obtained during the production of polyurethane foams, such as cuttings, sawn waste or material which has not passed quality control, but also, for example, from polyurethane foam waste (so-called waste foam) which has reached the end of its service life, for example foam from used refrigeration appliances, used insulation materials or insulation boards, used sealing foams, used mattresses, used furniture, used sound-absorbing materials, used packaging foams or used vehicles.

[0006] However, to date, the use of high proportions of such recycled polyols has generally led to a deterioration in the foam quality, so that there are generally significant limitations on the amount of recycled polyols used in polyurethane foams.

[0007] Polyurethane foams, in particular rigid foams, are typically produced using cell-stabilizing or foam-stabilizing additives (so-called foam stabilizers) to ensure a fine-celled, homogeneous, and low-defect foam structure, thereby substantially positively influencing the rigid foam's performance characteristics, such as thermal insulation. Surfactants based on polyether-modified siloxanes are particularly effective and therefore represent a preferred type of foam stabilizer. These so-called polyether siloxane foam stabilizers (PES) are well known from the prior art and are widely described, for example, in CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008 / 0125503, US 2015 / 0057384, EP 1520870A1, EP 1211279, EP 0867464, EP 0867465, and EP 0275563.

[0008] Against this background, it was an object of the present invention to be able to provide polyurethane foams which comprise recycled polyols and have particularly advantageous usage properties, such as in particular low thermal conductivity and / or good surface quality. Summary of the Invention

[0009] In the context of the present invention, it has surprisingly been found that this can be achieved by the use according to the invention of certain polyether siloxane foam stabilizers as specified in claim 1 .

[0010] This object is achieved by the subject matter of the present invention. The present invention provides a composition for preparing 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 reaction and / or the isocyanate-water reaction and / or the isocyanate trimerization,

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

[0015] (E) at least one chemical and / or physical blowing agent,

[0016] wherein the at least one foam stabilizer is selected from polyether siloxanes of the general average composition according to formula 1,

[0017] M a M b 1 D c D d 1(Formula 1)

[0018] in

[0019]

[0020] a=0 to 2, particularly preferably 0 to 0.5,

[0021] b=0 to 2, particularly preferably 1.5 to 2,

[0022] c=8 to 150, preferably 18 to 100, particularly preferably 18 to 70,

[0023] d=0 to 20, preferably 1 to 16, particularly preferably 1 to 13,

[0024] Where a+b=2, and for b=0, d>1, and for d=0, b=1.5 to 2,

[0025] R = each independently the same or different alkyl group having 1 to 16 carbon atoms, the same or different aryl group having 6 to 16 carbon atoms, -H or -OR 2 , preferably methyl, ethyl, phenyl or H, especially methyl,

[0026] R 2 = each independently the same or different alkyl group having 1 to 16 carbon atoms, the same or different aryl group having 6 to 16 carbon atoms or H,

[0027] R 1 = each independently identical or different polyether group, preferably identical or different polyether groups having a common average composition according to formula 2,

[0028]

[0029] R 3 = each independently the same or different divalent alkyl radical having 2 to 15 carbon atoms, preferably the same or different divalent alkyl radical having 3 to 6 carbon atoms, particularly preferably -(CH2)3-,

[0030] R 4 = each independently identical or different alkyl radical having 1 to 18 carbon atoms and optionally having an ether function, or identical or different aryl radicals having 6 to 18 carbon atoms and optionally having an ether function, or H, preferably H, ethyl or benzyl,

[0031] R 5 = each independently the same or different selected from R 2 and C(O)R 2 A group of which methyl, butyl, -H or C(O)Me is preferred,

[0032] e=0 to 100, preferably 0 to 80, especially 0 to 50,

[0033] f=0 to 100, preferably 0 to 80, especially 0 to 50,

[0034] g=0 to 100, preferably 0 to 80, especially 0 to 50,

[0035] h=0 to 100, preferably 0 to 40, particularly preferably 0,

[0036] Where e+f+g+h is > 0,

[0037] Of these, very particular preference is given to polyether groups R 1 At least one of the following corresponds to at least one of Category 1 and Category 2:

[0038] Category 1, based on formula 2:

[0039] e=8 to 16,

[0040] f=g=h=0,

[0041] or

[0042] e+f+g=15 to 34,

[0043] (f+g) / (e+f+g)>0 to 0.25, particularly preferably 0.1 to 0.2,

[0044] h=0,

[0045] Category 2, based on formula 2:

[0046] e+f+g=7 to 15,

[0047] (f+g) / (e+f+g)≥0.15 to 0.8,

[0048] h=0,

[0049] or

[0050] e+f+g=13 to 32,

[0051] (f+g) / (e+f+g)≥0.25 to 0.8, particularly preferably 0.3 to 0.4,

[0052] h=0,

[0053] And wherein, the polyether siloxane of Formula 1 is 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 entire polyol component. DETAILED DESCRIPTION

[0054] The polyether siloxanes useful according to the invention, such as those described in particular in one of the patent claims, can be obtained in a conventional manner known to those 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 by way of example using a number of working examples.

[0055] The subject matter of the present invention is associated with various advantages. For example, it allows the provision of PU foams that offer significant advantages in terms of sustainability while still meeting known requirements. These PU foams are advantageously dimensionally and hydrolytically stable, possess very good insulating properties, and have a high surface quality. This is advantageously achieved without compromising other properties of the material. The provision of rigid PU foams also enables particularly fine-pored, homogeneous, and low-defect foam structures.

[0056] A particularly preferred embodiment of the present invention corresponds to the presence in the composition according to the invention of at least one polyether siloxane of the formula (1) having the following characteristics: the polyether R present in the polyether siloxane in question 1 At least one of satisfies the above-mentioned category 1, wherein when e=8 to 16 and f=g=h=0, it is a particularly preferred variant of category 1.

[0057] A further particularly preferred embodiment of the present invention is when at least one polyether siloxane of the formula (1) is present in the composition according to the invention, which comprises at least two polyethers of the general formula (2), wherein at least one of these polyethers must satisfy the aforementioned category 1 and at least one of these polyethers must satisfy the aforementioned category 2, and the preferred ratio of polyethers of category 1 to polyethers of category 2 in the polyether siloxanes concerned corresponds to 10:90 to 90:10% by weight, particularly preferably 20:80 to 80:20% by weight and in particular 30:70 to 70:30% by weight.

[0058] It is a further particularly preferred embodiment of the present invention when the composition according to the invention has the following features: at least two polyether siloxanes of the formula (1) are present, wherein at least one of these polyether siloxanes comprises at least one polyether of the general formula (2) satisfying the above-mentioned class 1 and at least one of these polyether siloxanes comprises at least one polyether of the general formula (2) satisfying the above-mentioned class 2, and wherein the preferred ratio of polyether siloxane of the formula (1) comprising at least one polyether of class 1 to polyether siloxane of the formula (1) comprising at least one polyether of class 2 is from 10:90% by weight to 90:10% by weight, particularly preferably from 20:80% by weight to 80:20% by weight and in particular from 30:70% by weight to 70:30% by weight.

[0059] It is a further particularly preferred embodiment of the present invention when the composition according to the invention has the following feature: 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.

[0060] It is a further particularly preferred embodiment of the present invention when the composition according to the invention has the following feature: the at least one recycled polyol used has been obtained by depolymerization of polyurethanes, preferably by hydrolysis, solvolysis, aminolysis, acidolysis, alcoholysis or diololysis, preferably diololysis, hydrolysis or aminolysis, particularly preferably diololysis, wherein various recycled polyols from different depolymerization processes can also be used.

[0061] It is likewise a further particularly preferred embodiment of the present invention when the composition according to the invention has the following feature: the at least one recycled polyol used is obtained by depolymerization of polyurethane foam, preferably rigid polyurethane foam, particularly preferably rigid polyurethane foam comprising polyether polyols and / or polyester polyols, by the process specified in claim 6, particularly preferably by glycolysis.

[0062] The at least one recycled polyol is preferably selected from recycled polyether polyols and recycled polyester polyols.Polyether polyols and polyester polyols are well known to those skilled in the art, and their known reactions with polyisocyanates enable tried and tested polyurethane production.

[0063] It is a further particularly preferred embodiment of the present invention when the composition according to the invention has the feature that the recycled polyol used is obtained from PU waste foam.

[0064] PU waste foam is especially the following PU foam, it

[0065] (i) from production waste obtained during the production of polyurethane foam, such as cuttings, sawing waste or material that has not passed quality control,

[0066] and / or

[0067] (ii) PU foams from PU foams that have reached the end of their service life, for example foams from used refrigeration appliances, used insulation materials or insulation boards, used sealing foams, used mattresses, used furniture, used sound-absorbing materials, used packaging foams, or foams from used vehicles.

[0068] The composition according to the invention comprises as a blowing agent:

[0069] (i) one or more hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane and / or n-pentane,

[0070] and / or

[0071] (ii) one or more hydrofluoroolefins and / or hydrohaloolefins, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) and / or 1336mzz,

[0072] And the water that must be there,

[0073] The same corresponds to a further particularly preferred embodiment of the invention.

[0074] In the context of the present invention, preferred PU foam formulations, in particular rigid PU foam formulations, have the composition given in Table 1.

[0075] Table 1: Composition of preferred PU foam formulations

[0076] Components parts by weight A polyol component comprising at least one recycled polyol 80 to 120 catalyst >0 to 15 Polyether siloxane 0.1 to 5 foaming agent >0 to 50 Additional additives (flame retardants, etc.) 0 to 200 Isocyanate index: 10 to 1000

[0077] The present invention further provides a process for preparing PU foam, preferably rigid polyurethane foam, based on a reaction mixture comprising a composition of the invention as described above, in particular as defined in any one of claims 1 to 9.

[0078] The method according to the invention for producing polyurethane foam, preferably rigid polyurethane foam, can be carried out by any known method, for example by manual mixing or preferably with the aid of a foaming machine. If the method is carried out using a foaming machine, high-pressure or low-pressure machines can be used. The method according to the invention can be carried out batchwise or continuously and can use, for example, 1K, 1.5K, or 2K systems as described in EP 3717538 A1, US Pat. No. 7776934 B2, EP 1400547 B1, or EP 2780384 B2.

[0079] With regard to further preferred embodiments and configurations of the method according to the invention, reference is also made to the statements already given above regarding the composition according to the invention.

[0080] The present invention further provides PU foams, in particular rigid PU foams, which are produced by the above-described process according to the invention, in particular using the composition according to the invention.

[0081] When the PU foam according to the present invention, in particular the rigid PU foam, has a mass fraction of 5 to 900 kg / m 3 , preferably 5 to 350 kg / m 3 , especially 8 to 200 kg / m 3This is a preferred embodiment of the present invention.

[0082] The present invention further relates to the use of the PU foam according to the invention, in particular rigid PU foam, as an insulating material and / or as a building material, in particular in construction applications, in particular in spray foam and / or 1 & 1.5 component canned foams, or in the refrigeration sector, as a sound absorber, as packaging foam, as imitation wood, as molding foam, as roof lining for automobiles, as automobile interior trim, as sealing foam or pipe covering for pipes.

[0083] Preferred compositions according to the present invention comprise the following ingredients:

[0084] A) a polyol component comprising at least one recycled polyol,

[0085] B) a polyisocyanate component,

[0086] C) catalysts which catalyze the isocyanate-polyol reaction and / or the isocyanate-water reaction and / or the isocyanate trimerization,

[0087] D) Foam stabilizer,

[0088] E) a blowing agent,

[0089] F) Optional further additives, preferably fillers, liquid flame retardants and the like.

[0090] The polyol component (A) is composed of at least one polyol and optionally at least one organic compound containing at least two isocyanate-reactive groups, preferably selected from OH groups, NH groups and NH2 groups. A polyol is an organic compound containing two or more hydroxyl groups (-OH).

[0091] If one of the above-mentioned organic compounds of the polyol component contains at least two OH groups, it is exclusively classified as a polyol for the purposes of the present invention. This means that if the organic compound of the polyol component is evaluated as both a polyol and an organic compound containing at least two isocyanate-reactive groups selected from OH groups, NH groups and NH2 groups, it is exclusively classified as a polyol for the purposes of the present invention.

[0092] The polyol component preferably comprises at least 50% by weight, based on its total weight, of such polyols which comprise exclusively hydroxyl groups (—OH) as isocyanate-reactive groups.

[0093] 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).

[0094] Suitable compounds that can generally be used when preparing PU foams are known to those skilled in the art and are described, for example, in "Kunststoffhandbuch, Band 7, Polyurethane [Plastics Handbook, volume 7, Polyurethanes]", Carl Hanser Verlag, 3rd Edition 1993, Chapter 3.1. Compounds having an OH number in the range of 10 to 1200 mg KOH / g are generally used.

[0095] Particularly preferred compounds are all polyether polyols and / or polyester polyols which are generally useful for preparing polyurethane systems, in particular polyurethane foams. Polyether polyols can be obtained, for example, by reacting polyfunctional alcohols or amines with alkylene oxides. Preferred polyester polyols are generally based on esters of polycarboxylic acids (which may be aliphatic, as in the case of adipic acid, or aromatic, as in the case of phthalic acid or terephthalic acid) with polyols (generally diols).

[0096] Furthermore, polyether polycarbonate polyols, natural oil-based 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), filled polyols and / or prepolymer-based polyols can be used.

[0097] According to the invention, the above-mentioned recycled polyols are at least partially used, ie the polyol component comprises at least one recycled polyol.

[0098] The polyisocyanate component (B) consists of at least one polyisocyanate having two or more isocyanate groups. Suitable polyisocyanates for the purposes of the present invention are all organic isocyanates having two or more isocyanate groups, in particular the aliphatic, cycloaliphatic, arylaliphatic and preferably aromatic polyfunctional isocyanates known per se.

[0099] Examples which may be mentioned here 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), preferably hexamethylene 1,6-diisocyanate (HMDI); cycloaliphatic diisocyanates, such as cyclohexane 1,3- and 1,4-diisocyanate and the corresponding isomer mixtures, methylenedicyclohexyl 4,4'-diisocyanate, cyclohexane 1,3- and 1,4-diisocyanate and the corresponding isomer mixtures; Diisocyanates (H12MDI), isophorone diisocyanate (IPDI), methylcyclohexyl 2,4- and 2,6-diisocyanate, and the corresponding isomer mixtures; preference is given to aromatic diisocyanates and polyisocyanates, such as toluene 2,4- and 2,6-diisocyanate (TDI) and the corresponding isomer mixtures, naphthalene diisocyanate, diethyltoluene diisocyanate, diphenylmethane 4,4'-, 2,2'-, or 2,4'-diisocyanate (MDI), and polymethylene polyphenyl polyisocyanate (PMDI, "polymeric MDI"). Organic polyisocyanates can be used alone or in the form of mixtures. The corresponding "oligomers" of the aforementioned diisocyanates, such as IPDI trimers based on isocyanurates, biuret, or uretdione, can also be used. Prepolymers based on the aforementioned isocyanates can also be used. Mixtures of MDI and more highly condensed analogs having an average functionality of 2 to 4, known as polymeric MDI (also known as "crude MDI"), and the various isomers of TDI in pure form or as isomer mixtures are particularly suitable. Isocyanates that have been modified by the addition of urethane, uretdione, isocyanurate, allophanate, and other groups, known as modified isocyanates, can also be used. Examples of particularly suitable isocyanates are described in detail, for example, in EP 1 712 578, EP 1 161 474, WO 00 / 58383, US 2007 / 0072951, EP 1 678 232, and WO 2005 / 085310, which are incorporated herein by reference in their entirety.

[0100] The preferred ratio of isocyanate groups to isocyanate-reactive groups, expressed as an index of the formulation (isocyanate index), i.e. the stoichiometric ratio of isocyanate groups to isocyanate-reactive groups (e.g. OH groups, NH groups) multiplied by 100, is in the range of 10 to 1000, preferably 40 to 400. An index of 100 represents a molar ratio of reactive groups of 1:1.

[0101] Suitable catalysts (C) which can be used for the preparation of polyurethanes, in particular PU foams, are known to the person skilled in the art from the prior art. In the context of the present invention, useful compounds are in particular all compounds which are able to catalyze the reaction of isocyanate groups with OH groups, NH groups or other isocyanate-reactive groups and / or the reaction of isocyanate groups with one another.

[0102] Conventional catalysts known from the prior art can be used, for example 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, the catalyst used may be a mixture of two or more such compounds.

[0103] Suitable amounts depend on the type of catalyst and may preferably be in the range of 0.05 to 5 pphp (= parts by weight based on 100 parts by weight of the polyol component) in the case of amine catalysts, or 0.1 to 10 pphp in the case of potassium salts.

[0104] As mentioned above, foam stabilizers (D) and their use in the production of PU foams are known to those skilled in the art. According to the present invention, at least one of the polyether siloxane foam stabilizers according to the present invention is used. In addition to the polyether siloxane foam stabilizers according to the present invention, further polyether siloxane foam stabilizers and Si-free surfactants may also be used. For example, EP 2295485 A1 describes the use of lecithin, while US Pat. No. 3746663 describes the use of structures based on vinylpyrrolidone. Additional 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 Pat. No. 5236961.

[0105] Blowing agents (E) and their use in the preparation of PU foams are known to those skilled in the art. The use of a blowing agent is optional; preferably, a blowing agent is used. The use of a blowing agent or a combination of two or more blowing agents depends in principle on the nature of the foaming process, on the nature of the system and on the use of the resulting PU foam. Both chemical blowing agents and / or physical blowing agents, as well as combinations of the two, can be used. Depending on the amount of blowing agent used, foams with high or low densities can be produced. For example, foams with a density of 5 kg / m² can be produced. 3 Up to 900kg / m 3 , preferably 5 to 350 kg / m 3 , particularly preferably 8 to 200 kg / m 3, especially 8 to 150 kg / m 3 The density of the foam.

[0106] Optional physical blowing agents that can be used are one or more suitable compounds with a suitable boiling point, for example hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane or n-pentane; hydrofluorocarbons (HFCs), preferably HFC 245fa, HFC 134a or HFC 365mfc; hydrochlorofluorocarbons (HCFCs), preferably HCFC 141b; hydrofluoroolefins (HFOs) 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.

[0107] The optional chemical blowing agent used may be one or more compounds which react with NCO groups and release gas, such as water or formic acid, or which release gas during the reaction as a result of the temperature increase, such as sodium bicarbonate.

[0108] It corresponds to a particularly preferred embodiment when the composition according to the invention comprises water as blowing agent in combination with a hydrocarbon having 5 carbon atoms, an HFO, a hydrohaloolefin or an HFC or a mixture thereof.

[0109] As optional further additives (F), one or more substances known in the prior art and used in the preparation of polyurethanes, in particular PU foams, may be used, for example crosslinkers, chain extenders, stabilizers against oxidative degradation (known as antioxidants), flame retardants, biocides, cell-refining additives, nucleating agents, cell openers, solid fillers, antistatic additives, thickeners, dyes, pigments, colorants, fragrances and / or emulsifiers, etc.

[0110] As optional flame retardants, the composition according to the invention may contain one or more flame retardants known to be suitable for the preparation of PU foams, for example halogen-containing or halogen-free organic phosphorus-containing compounds, for example triethyl phosphate (TEP), tris(1-chloro-2-propyl) phosphate (TCPP), tris(2-chloroethyl) phosphate (TCEP), dimethyl methanephosphonate (DMMP), dimethyl propanephosphonate (DMPP), ammonium polyphosphate or red phosphorus, nitrogen-containing compounds such as melamine, melamine cyanurate or melamine polyphosphate, or halogenated compounds. Mixtures of different flame retardants can also be used.

[0111] Unless the contrary is apparent from the present description, any preferred or particularly preferred embodiment of the present invention may be combined with one or more other preferred or particularly preferred embodiments of the present invention.

[0112] The subject matter of the present invention is described below by way of example, without any intention that the present invention is limited to these exemplary embodiments, and the scope of application of the present invention is obvious from the entire specification and claims. In the case of reporting the range, general formula or category of the compound, these are intended to cover not only the corresponding range or group of the compound explicitly mentioned, but also all sub-ranges and sub-groups of the compound that can be obtained by removing a single value (range) or compound. In the case of citing a document in the context of this specification, its entirety, in particular with respect to the subject matter forming the context of the cited document, is intended to form a part of the disclosure of the present invention. Unless otherwise stated, percentages are in percentage by weight. In the case of reporting average values, these are numerical averages unless otherwise stated. In the case of reporting parameters that have been determined by measurement, unless otherwise stated, the measurement has been carried out at a temperature of 23°C and standard pressure.

[0113] Example

[0114] Synthesis of Polyether Silicone Foam Stabilizer (PES)

[0115] As a Pt catalyst for preparing the polyethersiloxanes, a xylene solution of Karstedt's catalyst (platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (CAS 68478-92-2)) was used. The Pt content of the solution was 2% by weight. The catalyst was obtained from Merck and used without further treatment.

[0116] To synthesize the polyethersiloxane, a three-necked flask equipped with a precision glass stirrer and a reflux condenser was initially charged with allyl polyether and SiH-functional siloxane corresponding to the composition reported in Table 2. The ratio of allyl polyether to SiH-functional siloxane was selected such that 1.4 moles of double bonds from the allyl polyether were present per mole of SiH functional groups. The apparatus was inerted with nitrogen, and the mixture was then heated to 80°C. Thereafter, 10 ppm of Pt, based on the total initial weight, was added in the form of the aforementioned Pt catalyst. An exothermic reaction occurred. Cooling was used to maintain the temperature below 110°C. The reaction mixture was then stirred at 100°C for 3 hours. A clear to slightly turbid product was always obtained.

[0117] PES14 and PES15 were prepared by mixing the corresponding foam stabilizers in a weight ratio of 1:1.

[0118] The polyether siloxanes corresponding to Formula 1 and Formula 2 shown in Table 2 were prepared and subjected to performance tests. For PES 1 to 15, R = methyl, R = 3 =-(CH2)3- and h = 0. PES1 to 3 are considered comparative examples not according to the present invention.

[0119] Table 2: Composition of polyether siloxane foam stabilizer (PES)

[0120]

[0121] *Comparative example not according to the present invention

[0122] Recycled polyol 1 was prepared by glycolysis according to the method of H&S Anlagentechnik from 2012: https: / / www.dbu.de / OPAC / ab / DBU-Abschlussbericht-AZ-29395.pdf. For this purpose, a reactor from Parr (Parr Instrumental Company) equipped with a glass inner container and a mechanical stirrer was filled with 294.0 g of a compressed PU foam piece (approximately 1 cm×1 cm). The reactor was stirred using a PU foam block from Evonik Operation GmbH, as described below. B8462 was used as a foam stabilizer to prepare a polyurethane foam for glycolysis corresponding to Formulation A from Table 3. 152.3 g of polyol R 471, 75.1 g of phthalic acid and 11.6 g of aqueous hydrogen peroxide solution (30% by weight in water). The reaction mixture was heated to 250° C. and kept at a temperature in the range of 237° C. to 256° C. for 5 hours. At the end of 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 R 471. The liquid reaction mixture was cooled to room temperature and, after being decanted, was used as Recycle Polyol 1. The recycling process was repeated to provide a sufficiently large amount of recycled polyol for use in foaming experiments.

[0123] Recycled polyol 2 was prepared in a similar manner to recycled polyol 1. Instead of freshly prepared foam, foam blocks from used polyether polyol-based PU insulation boards were used.

[0124] The performance comparison was carried out using the formulations shown in Table 3. A comparative foaming operation was carried out by manual mixing. For this purpose, the polyol, catalyst, water, foam stabilizer, blowing agent and any other additives were weighed into a beaker and mixed with a disk stirrer (diameter 6 cm) at 1000 rpm for 30 seconds. The beaker was reweighed to determine the amount of blowing agent that had evaporated during the mixing operation and replenished. MDI was now added, the reaction mixture was stirred with the stirrer at 3000 rpm for 5 seconds and immediately transferred to an aluminum mold thermostated to 45°C and having dimensions of 145 cm×14 cm×3.5 cm, the mold being tilted at an angle of 10° (along the 145 cm long side) and lined with polyethylene film. In this case, the foam formulation was introduced on the lower side so that the expanding foam filled the mold in the feed area and rose in the direction of the higher side.

[0125] To determine the flow behavior, the amount of foam formulation used was calculated so that it was approximately 10% less than the amount required for the minimum filling of the mold (approximately 260 g). After 10 minutes, the foam was demoulded and the average length of the test sample was determined. The reduced length was then determined as the quotient of the product of the average length of the test sample, the measured air pressure, and the average weight of all the test samples studied, multiplied by the standard air pressure (1013.25 hPa) and the weight of the test sample. The flow differences reported in Tables 4 to 8 are expressed as the percentage difference between the reduced length of the test sample and a reference test sample prepared using PES1 as foam stabilizer and the corresponding formulation.

[0126] To determine all further properties, for the second test sample, the amount of foam formulation used was calculated so that it was approximately 10% higher than the amount required for the minimum filling of the mold. After 10 minutes, the foam was demoulded. One day after foaming, the foam properties were analyzed. Surface quality and internal defects were subjectively evaluated on a scale of 1 to 10, with 10 representing an (ideal) defect-free foam and 1 representing a foam with very significant defects. The thermal conductivity coefficient (λ value in mW / m·K) was measured on 2.5 cm thick disks at an average temperature of 10°C using a HestoLambda Control instrument, model HLC X206, in accordance with the specifications of standard EN 12667:2001.

[0127] The results are compiled in Tables 4 to 8.

[0128] Table 3: PU formulations. Amounts reported are in parts by weight

[0129]

[0130] *From Huntsman R 471, OH value 470 mg KOH / g**Amine catalyst from Evonik Operations GmbH

[0131] **Polymeric MDI, 200 mPa·s, 31.5% NCO, functionality 2.7.

[0132] Table 4: Foam properties of Formulation A foam

[0133]

[0134] *Comparative example not according to the present invention

[0135] Table 5: Foam Properties of Formulation B Foam

[0136]

[0137] *Comparative example not according to the present invention

[0138] Table 6: Foam Properties of Formulation C Foam

[0139]

[0140] *Comparative example not according to the present invention

[0141] Table 7: Foam Properties of Formulation D Foam

[0142]

[0143] *Comparative example not according to the present invention

[0144] Table 8: Foam properties of Formulation E foam

[0145]

[0146] *Comparative example not according to the present invention

[0147] Those foam stabilizers that showed the most promising results in Formulations B and D were selected for use in Formulations C and E, which had relatively high recycled polyol contents.

[0148] The results show that the foam stabilizers not according to the invention lead to significantly worse property profiles, characterized in particular by higher thermal conductivity, worse flow properties and a worse surface, when recycled polyols are used in Formulations B to E. On the other hand, with the foam stabilizers according to the invention, the property profiles can be significantly improved and comparable performance can be achieved to formulations without recycled polyols.

Claims

1. A composition for preparing 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 reaction and / or the isocyanate-water reaction and / or the isocyanate trimerization, (D) at least one foam stabilizer, (E) at least one chemical and / or physical blowing agent, It is characterized in that The at least one foam stabilizer is selected from polyether siloxanes of the general average composition according to Formula 1, M a M b 1 D c D d 1 (Formula 1) in, 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 the same or different alkyl group having 1 to 16 carbon atoms, the same or different aryl group having 6 to 16 carbon atoms, -H or -OR 2 , preferably methyl, ethyl, phenyl or H, especially methyl, R 2 = each independently the same or different alkyl group having 1 to 16 carbon atoms, the same or different aryl group having 6 to 16 carbon atoms or H, R 1 = each independently identical or different polyether group, preferably identical or different polyether groups having a common average composition according to formula 2, R 3 = each independently the same or different divalent alkyl radical having 2 to 15 carbon atoms, preferably the same or different divalent alkyl radical having 3 to 6 carbon atoms, particularly preferably -(CH2)3-, R 4 = each independently the same or different alkyl radical having 1 to 18 carbon atoms and optionally having an ether function, or the same or different aryl radical having 6 to 18 carbon atoms and optionally having an ether function, or H, preferably H, ethyl or benzyl, R 5 = each independently the same or different selected from R 2 and C(O)R 2 A group of which methyl, butyl, -H or C(O)Me is preferred, e=0 to 100, preferably 0 to 80, especially 0 to 50, f=0 to 100, preferably 0 to 80, especially 0 to 50, g=0 to 100, preferably 0 to 80, especially 0 to 50, h=0 to 100, preferably 0 to 40, particularly preferably 0, where e+f+g+h>0, Among them, very particular preference is given to polyether groups R 1 At least one of the following corresponds to at least one of Category 1 and Category 2: Category 1, based on formula 2: e=8 to 16, f=g=h=0, 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, based on 100 parts by weight of all polyol components, the total usage amount of the polyether siloxane of Formula 1 is 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, and particularly preferably 0.5 to 5 parts by weight.

2. The composition according to claim 1, characterized in that There is at least one polyether siloxane of formula (1) having the following characteristics: the polyether R present in the polyether siloxane 1 At least one of satisfies category 1, wherein it is a particularly preferred variant of category 1 when e=8 to 16 and f=g=h=0.

3. The composition according to claim 1 or 2, characterized in that At least one polyether siloxane of the formula (1) is present, which comprises at least two polyethers of the general formula (2), wherein at least one of these polyethers must satisfy class 1 and at least one of these polyethers must satisfy class 2, and the preferred ratio of polyethers of class 1 to polyethers of class 2 in the polyether siloxanes concerned corresponds to 10:90 to 90:10% by weight, particularly preferably 20:80 to 80:20% by weight, in particular 30:70 to 70:30% by weight.

4. The composition according to any one of claims 1 to 3, characterized in that At least two polyether siloxanes of the formula (1) are present, wherein at least one of these polyether siloxanes contains at least one polyether of the general formula (2) that satisfies class 1 and at least one of these polyether siloxanes contains at least one polyether of the general formula (2) that satisfies class 2, and wherein the preferred ratio of the polyether siloxane of the formula (1) containing at least one polyether of class 1 to the polyether siloxane of the formula (1) containing at least one polyether of class 2 is 10:90 to 90:10% by weight, particularly preferably 20:80 to 80:20% by weight, in particular 30:70 to 70:30% by weight.

5. The composition according to any 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 greater than 50 parts by weight, particularly preferably greater than 70 parts by weight, based on 100 parts by weight of all polyol components.

6. The composition according to any one of claims 1 to 5, characterized in that The recycled polyols used are obtained by depolymerization of polyurethanes, preferably by hydrolysis, solvolysis, aminolysis, acidolysis, alcoholysis or diollysis, preferably diollysis, hydrolysis or aminolysis, particularly preferably diollysis, wherein various recycled polyols from different depolymerization processes can also be used.

7. The composition according to any 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 rigid polyurethane foam comprising polyether polyols and / or polyester polyols, according to the process described in claim 6, particularly preferably by glycolysis.

8. The composition according to any one of claims 1 to 7, characterized in that The recycled polyol used was obtained from PU waste foam.

9. The composition according to any one of claims 1 to 8, characterized in that The composition comprises the following as a blowing agent: (i) one or more hydrocarbons having 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane and / or n-pentane, and / or (ii) one or more hydrofluoroolefins and / or hydrohaloolefins, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) and / or 1336mzz, And water must be present.

10. Process for the preparation of PU foams, preferably rigid polyurethane foams, based on a reaction mixture comprising a composition as defined in any one of claims 1 to 9.

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

12. Use of the PU foam, preferably rigid PU foam, according to claim 11 as an insulation material and / or as a building material, in particular in construction applications, in particular in spray foams and / or 1 & 1.5 component canned foams, or in the refrigeration sector, as a sound absorber, as a packaging foam, as imitation wood, as a molded foam, as a roof lining for automobiles, as an interior trim for automobiles, as a sealing foam or as a pipe covering for pipes.

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