EP4301800A1

EP4301800A1 - Production of polyurethane foam

Info

Publication number: EP4301800A1
Application number: EP22707736.9A
Authority: EP
Inventors: Michael SUCHAN; Joachim Venzmer; Jochen Kleinen; Marc Zimmermann
Original assignee: Evonik Operations GmbH
Current assignee: Evonik Operations GmbH
Priority date: 2021-03-02
Filing date: 2022-02-24
Publication date: 2024-01-10
Also published as: JP2024511293A; WO2022184543A1; CA3210253A1; CN116917366A; KR20230154044A

Abstract

The invention relates to a composition for producing rigid PU foam, comprising at least one polyisocyanate component, a blowing agent, a solid flame retardant, optionally a catalyst that catalyzes the formation of a urethane or isocyanurate bond, the composition containing at least one surfactant based on a quarternary ammonium compound.

Description

Production of polyurethane foam

The present invention is in the field of polyurethanes, particularly polyurethane foams. In particular, it relates to the production of rigid polyurethane foams using solid flame retardants and surfactants based on quaternary ammonium compounds, such as ester quats and/or alkyl quats, compositions for producing such foams, and also the use of these foams. These are rigid polyurethane foams.

In the context of the present invention, polyurethane (PU) is understood to mean in particular a product obtainable by reaction of polyisocyanates and polyols or compounds having isocyanate-reactive groups. In addition to the polyurethane, other functional groups can also be formed, such as uretdiones, carbodiimides, isocyanurates, allophanates, biurets, ureas and/or uretimines. For the purposes of the present invention, PU is therefore understood to mean both polyurethane and polyisocyanurate, polyureas and polyisocyanate reaction products containing uretdione, carbodiimide, allophanate, biuret and uretimine groups. In the context of the present invention, polyurethane foam (PU foam) is understood to mean foam which is obtained as a reaction product based on polyisocyanates and polyols or compounds with isocyanate-reactive groups. In addition to the polyurethane that gives the product its name, other functional groups can also be formed, such as allophanates, biurets, ureas, carbodiimides, uretdiones, isocyanurates or uretimines.

In connection with the provision of PU foams, in particular PU rigid foams, it is particularly important to produce PU foams which have good flame retardant properties. For this reason, flame retardants are used. Flame retardants are substances that are known per se and are used to limit, slow down or prevent the spread of fires. The known prior art describes corresponding flame retardants which have flame-retardant properties and are suitable for use in the PU foam sector.

More recently, solid flame retardants such as ammonium polyphosphate (APP) have also been increasingly used in the production of PU rigid foam because they have ecological and toxicological advantages over liquid flame retardants that often contain halogens, such as tris(2-chloroisopropyl)phosphate (TCCP). . However, the liquid flame retardants are much easier to process. The use of solids brings significant problems in terms of dispersion in the liquid raw materials and with the processing itself. This includes, among other things, sedimentation, redispersion after sedimentation, inhomogeneous distribution in the PU rigid foam and, above all, a resulting inhomogeneous property profile of the PU foams produced in this way. Efforts have been made to use dispersing additives to overcome these problems, but so far without really convincing results. Among other things, the use of dispersing additives has always been accompanied by a sharp increase in the viscosity of the components, which makes processing significantly more difficult or even impossible. Against this background, the specific object of the present invention was to make it possible to provide PU rigid foams which contain solid flame retardants, but to overcome the above-mentioned problems of sedimentation, redispersion after sedimentation, and inhomogeneous distribution in the foam, in particular while avoiding excessive distribution Increase in the viscosity of the components.

In this context, it was surprisingly found within the scope of the present invention that the use of surfactants based on quaternary ammonium compounds, such as ester quats and/or alkyl quats, enables the desired significant improvement in redispersion, sedimentation stability and a more homogeneous property profile of the foam. The viscosity of the components is only influenced to a significantly lesser extent.

The above object is achieved by the subject matter of the invention. The subject of the invention is a composition for the production of PU rigid foam, comprising at least one polyisocyanate component, at least one polyol component, blowing agent, solid flame retardant, optionally a catalyst which catalyzes the formation of a urethane or isocyanurate bond, the composition having at least a surfactant based on quaternary ammonium compounds, such as ester quat or alkyl quat or amidoamine quat or imidazolinium quat.

The subject of the invention is associated with a variety of advantages. It enables the provision of rigid PU foams with good flame retardant properties. This is advantageously made possible without impairing the other properties of the foam, in particular its mechanical properties. With a view to the provision of PU rigid foams, particularly fine-lined, uniform and low-defect foam structures are also made possible. This makes it possible to provide corresponding PU foams with particularly good performance properties and a homogeneous profile of properties. The invention enables a particularly homogeneous Distribution of solid flame retardants in polyurethane foam. It also makes it possible, if desired, to add a particularly large amount of solid flame retardants to the polyurethane foam. Overall, the invention enables simple processing of the solid flame retardants in the context of foam production. The solid flame retardants can be introduced into the reaction mixture very easily together with the surfactant based on quaternary ammonium compounds, such as preferably ester quat and/or alkyl quat, for example via one of the two reaction components (polyol component or polyisocyanate component). Introduction via the polyol component is preferred. Sedimentation problems during storage of the dispersion of reaction component and solid can be significantly reduced or even avoided by the present invention. The invention also enables very good redispersibility of the solid in the event of sedimentation after very long storage, so that constant stirring or mixing during storage, for example, is no longer necessary. The invention also enables a more homogeneous distribution of the solids in the polyurethane foam, which leads to a more uniform profile of properties.

Surfactants based on quaternary ammonium compounds, such as esterquats,

Amidoamine quats, imidazolinium quats, cetylpyridinium chloride and/or alkyl quats are known per se to those skilled in the art. For example, ester quats and alkyl quats are surfactants based on quaternary ammonium compounds with at least one long hydrocarbon radical. While alkyl quats are generally tetraalkyl ammonium salts, ester quats are generally based on quaternary triethanol-methyl ammonium or quaternary diethanol-dimethyl ammonium compounds which have been esterified with at least one fatty acid.

Alkyl quats and ester quats have long been used in cosmetics or detergents and cleaning agents, e.g. fabric softeners, and their production has long been known to those skilled in the art. Alkyl quats can be prepared, for example, by reacting the corresponding amine with methylating agents such as chloromethane or dimethyl sulfate. Esterquats can be produced, for example, by esterification of methyldiethanolamine or triethanolamine with fatty acids and subsequent quaternization with, for example, dimethyl sulfate or chloromethane.

According to a particularly preferred embodiment of the invention, at least one ester quat of the formula (1) or (2), an alkyl quat of the formula (3), an imidazolinium quat of the formula (4), an amidoamine quat of the Formula (5) and / or cetylpyridinium chloride used, wherein with R ¹ being an acyl radical of a saturated or mono- or polyunsaturated, linear or branched fatty acid with a chain length of 8 to 22 carbon atoms or the acyl radical of ricinoleic acid, or hydrogen, where a compound of the formula (1) or (2) has different radicals R ¹ may contain and with the proviso that at least one radical R ¹ must be one of the acyl radicals mentioned, with R ² being an alkyl radical having 1 to 6 carbon atoms or hydrogen, preferably hydrogen, methyl, ethyl, propyl or isopropyl, particularly preferably hydrogen or methyl R ³ is an alkyl radical having 1 to 6 carbon atoms or hydrogen, preferably hydrogen, methyl, ethyl, propyl or isopropyl, particularly preferably methyl or hydrogen, with R ⁴ being an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, preferably methyl, ethyl , propyl or isopropyl, more preferably ethyl or methyl, most preferably methyl, wherein a compound of the form el (1) or (2) may contain different radicals R ⁴ and where n=0 to 20, preferably 0 to 10, particularly preferably 0, where a=1 to 3 and b=1 to 3, with the proviso that a + b = 4, and/or where Formula (3) R ⁵ is a saturated or mono- or polyunsaturated, linear or branched alkyl radical having a chain length of 8 to 24 carbon atoms, where a compound of the formula (3) can contain different R ⁵ radicals, R ⁶ is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or a benzyl radical or hydrogen, preferably methyl, ethyl, propyl, isopropyl or benzyl, particularly preferably ethyl or methyl, very particularly preferably methyl, where a compound of the formula (3) can contain different radicals R ⁶ and where c = 1 bis 3 and d = 1 to 3, with the proviso that c + d = 4, and/or where Formula (4) with R ⁷ an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, preferably methyl, ethyl, propyl or isopropyl, particularly preferably ethyl or methyl, very particularly preferably methyl, with R ⁸ a saturated or mono- or polyunsaturated one , linear or branched alkyl radical having 8 to 22 carbon atoms or a radical 0(C0)R ¹ °, with R ¹⁰ an aliphatic, saturated or mono- or polyunsaturated, linear or branched alkyl radical with 7 to 21 carbon atoms, with R ⁹ an aliphatic saturated or mono- or polyunsaturated, linear or branched alkyl radical having 7 to 21 carbon atoms, with Z being an NH group or oxygen, where e can assume integer values between 1 and 4, and/or where, Formula (5) R ¹¹ is a saturated or mono- or polyunsaturated, linear or branched alkyl radical having a chain length of 7 to 21 carbon atoms, R ¹² is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, preferably methyl, ethyl, propyl or isopropyl, especially preferably ethyl or methyl, very particularly preferably methyl, where a compound of the formula (5) can contain different radicals R ¹² and where f can assume integer values between 0 and 5, where h=1 or 2 and g=2 or 3, with with the proviso that h + g = 4, where a compound of formula (5) can have different values for f for h = 2 and can contain different radicals R ¹¹ , provided that R ⁴ , R ⁶ , R ⁷ or R ¹² comprises a hydroxyethyl radical , this can also be alkoxylated and this optionally alkoxylated hydroxyethyl radical can contain repeating units based on ethylene oxide, propylene oxide, butylene oxide and/or styrene oxide and 1-15 repeating units n, preferably 1-10 repeat units.

Corresponding compositions which contain corresponding quaternary ammonium compounds show particularly advantageous results with regard to the advantages according to the invention described above.

It corresponds to a further particularly preferred embodiment of the invention if in the formula (1) and/or formula (2) R ¹ is selected from the acyl radicals of the acids from the group comprising oleic acid, isostearic acid, lauric acid, palmitic acid, elaidic acid, vaccenic acid, gadoleic acid, Icosenic acid, cetolic acid, erucic acid, nervonic acid, linoleic acid, alpha-linolenic acid, gamma-linolenic acid, calendulic acid, punicic acid, alpha-elaeostearic acid, beta-elaeostearic acid, arachidonic acid, timnodonic acid, clupanodonic acid and/or cervonic acid.

It is furthermore preferred if a=b=2 in formula (1) and/or h=1 and g=3 in formula (5). This also corresponds to a further particularly preferred embodiment of the invention.

A composition according to the invention containing at least one counter-anion to the compound of the general formula (1), (2), (3), (4) and/or (5) selected from the group comprising chloride, bromide, iodide, alkyl sulfate, for example methyl sulfate, Ethyl sulphate, alkyl sulphonate, for example methyl sulphonate, triflate, tosylate, phosphate, sulphate, hydrogen sulphate, lactate, glycolate, acetate and/or citrate corresponds to a further particularly preferred embodiment of the invention. If surfactants based on a quaternary ammonium compound are contained in the composition according to the invention in a total amount of 0.1 to 10 parts, preferably 0.1 to 5 parts, particularly preferably 0.1 to 4 parts, based on 100 parts of polyols, then there is a further particularly preferred embodiment of the invention. The composition according to the invention necessarily contains at least one solid flame retardant. Solid flame retardants which can be used in PU rigid foams are also known per se and the present invention is also not restricted in the selection of the solid flame retardants. However, according to a preferred embodiment of the invention, certain solid flame retardants are used in the composition according to the invention, so that it preferably comprises melamine, melamine cyanurate and/or phosphorus-based flame retardants such as ammonium polyphosphate or red phosphorus. The use of ammonium polyphosphate (APP) [CAS: 68333-79-9] is particularly preferred. It is also particularly preferred if the composition according to the invention contains a mixture of ammonium polyphosphate and melamine or ammonium polyphosphate with a melamine coating or shell or means as a solid flame retardant Contains melamine or melamine-formaldehyde resin microencapsulated ammonium polyphosphate. According to a further preferred embodiment of the invention, the solid flame retardant is contained in the composition according to the invention in a total amount of 1 to 60 parts, preferably 5 to 50 parts, particularly preferably 8 to 30 parts, based on 100 parts of polyols. Furthermore, it is particularly preferred if the composition according to the invention additionally contains at least one foam stabilizer, preferably based on a polyethersiloxane, in amounts of 0.5 to 4 parts, based on 100 parts of polyols. Foam stabilizers, preferably based on a polyether siloxane, are known per se. Suitable foam stabilizers are described below.

Another subject of the invention is a process for the production of PU rigid foams, based on foamable reaction mixtures containing polyisocyanates, at least one polyol component, blowing agent, solid flame retardant, optionally a catalyst and optionally other additives, with at least one surfactant based on quaternary ammonium compounds, preferably as described above, preferably using a composition according to the invention as described above, in particular as described in more detail above in the preferred embodiments. The process according to the invention for producing PU foams can be carried out by known methods, for example by hand mixing or preferably with the aid of foaming machines. If the process is carried out using foaming machines, high-pressure or low-pressure machines can be used. The process according to the invention can be carried out either batchwise or continuously.

A particularly preferred PU rigid foam formulation within the meaning of this invention results in a density of 5 to 900 kg/m ³ and has the composition given in Table 1, which corresponds to a preferred embodiment of the invention:

Table 1 :

Composition of a preferred PU rigid foam formulation For further preferred embodiments and configurations of the method according to the invention, reference is also made to the statements made above in connection with the composition according to the invention.

A further subject matter of the present invention is a PU rigid foam, produced by the aforementioned method according to the invention, in particular using a composition according to the invention.

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 , in particular 10 to 200 kg/m ³ , this is a preferred embodiment of the invention . Another subject of the present invention relates to the use of PU rigid foam according to the invention, as mentioned above, as insulating material and/or as a construction material, in particular in construction applications, in particular in spray foam or in the cooling area, as acoustic foam for sound absorption, as packaging foam, as headliner for automobiles or pipe coatings for tubes.

The use of surfactants based on quaternary ammonium compounds, in particular as defined above with formula (1), (2), (3), (4) and / or (5), in the production of solid flame retardant-containing rigid PU foams, in particular under Use of a composition according to the invention, in particular as defined in one of the claims, represents a further subject matter of the invention. Surfactants based on quaternary ammonium compounds, such as ester quats and/or alkyl quats, are preferably used as dispersing additives in the production of PUs containing solid flame retardants -Rigid foams, in particular for improving the dispersibility, redispersibility and/or sedimentation stability of solid flame retardants in compositions for the production of PU rigid foam.

A preferred composition according to the invention contains the following components: a) surfactant(s) based on quaternary ammonium compounds, in particular as defined above with formula (1), (2), (3), (4) and/or (5) b) isocyanate -reactive components, in particular polyols c) at least one polyisocyanate and/or polyisocyanate prepolymer d) a catalyst which accelerates or controls the reaction of polyols b) with the isocyanates c) e) optionally foam stabilizer f) one or more blowing agents g ) solid flame retardant h) optional other additives, fillers, liquid flame retardants, etc.

Polyols suitable as isocyanate-reactive component or polyol component b) for the purposes of the present invention are all organic substances having two or more isocyanate-reactive groups, preferably OH groups, and preparations thereof. Preferred polyols are all polyether polyols and/or polyester polyols and/or hydroxyl-containing aliphatic polycarbonates commonly used for the production of polyurethane systems, in particular polyurethane coatings, polyurethane elastomers or in particular PU foams, in particular polyether polycarbonate polyols and/or polyols of natural origin, so-called “natural oil-based polyols” (NOPs). The polyols usually have a functionality of 1.8 to 8 and number-average molecular weights in the range from 500 to 15,000. Polyols with OH numbers in the range from 10 to 1200 mg KOH/g are usually used.

Polyols or mixtures thereof are preferably used to produce PU rigid foams, with the proviso that at least 90 parts by weight of the polyols present, based on 100 parts by weight of polyol component, have an OH number greater than 100, preferably greater than 150, in particular greater than 200 exhibit. The basic difference between flexible foam and rigid foam is that flexible foam shows elastic behavior and can be reversibly deformed. If the flexible foam is deformed by the application of force, it returns to its original shape as soon as the application of force is removed. Hard foam, on the other hand, is permanently deformed. In the context of the present invention, rigid PU foam is understood to mean, in particular, a foam according to DIN 7726:1982-05, which preferably has a compressive strength according to DIN 53 421/DIN EN ISO 604:2003-12 of advantageously ≧20 kPa, preferably ≧80 kPa ^ 100 kPa, more preferably ^ 150 kPa, particularly preferably ^ 180 kPa. Furthermore, according to DIN EN ISO 4590:2016-12, the rigid PU foam advantageously has a closed-cell content of greater than 50%, preferably greater than 80% and particularly preferably greater than 90%.

Polyether polyols can be prepared by known methods, for example by anionic polymerization of alkylene oxides in the presence of alkali metal hydroxides, alkali metal alcoholates or amines as catalysts and with the addition of at least one starter molecule that preferably contains 2 or 3 reactive hydrogen atoms or by cationic polymerization of alkylene oxides in the presence of Lewis -Acids such as antimony pentachloride or boron trifluoride etherate or by double metal cyanide catalysis. Suitable alkylene oxides contain 2 to 4 carbon atoms in the alkylene radical. Examples are tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide; ethylene oxide and 1,2-propylene oxide are preferably used. The alkylene oxides can be used individually, cumulatively, in blocks, alternately one after the other, or as mixtures. In particular, compounds with at least 2, preferably 2 to 8, hydroxyl groups or with at least two primary amino groups in the molecule are used as starter molecules. Examples of starter molecules that can be used are water, di-, tri- or tetrahydric alcohols such as ethylene glycol, 1,2- and 1,3-propanediol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, castor oil, etc., higher polyfunctional polyols, in particular sugar compounds such as glucose, sorbitol, mannitol and sucrose, polyhydric phenols, resols, such as oligomeric condensation products of phenol and Formaldehyde and Mannich condensates from phenols, formaldehyde and dialkanolamines and melamine, or amines such as aniline, EDA, TDA, MDA and PMDA, particularly preferably TDA and PMDA. The selection of the suitable starter molecule depends on the respective field of application of the resulting polyether polyol in the production of polyurethane.

Polyester polyols are based on esters of polybasic aliphatic or aromatic carboxylic acids, preferably having 2 to 12 carbon atoms. Examples of aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, maleic acid and fumaric acid. Examples of aromatic carboxylic acids are phthalic acid, isophthalic acid, terephthalic acid and the isomeric naphthalenedicarboxylic acids. The polyester polyols are obtained by condensing these polybasic carboxylic acids with polyhydric alcohols, preferably diols or triols having 2 to 12, particularly preferably 2 to 6, carbon atoms, preferably trimethylolpropane and glycerol.

Polyether polycarbonate polyols are polyols containing carbon dioxide bound as a carbonate. Since carbon dioxide is produced in large quantities as a by-product in many processes in the chemical industry, the use of carbon dioxide as a comonomer in alkylene oxide polymerizations is of particular commercial interest. Partial replacement of alkylene oxides in polyols with carbon dioxide has the potential to significantly reduce the cost of polyol production. In addition, the use of CO as a comonomer is ecologically very advantageous, since this reaction represents the conversion of a greenhouse gas into a polymer. The production of polyether polycarbonate polyols by addition of alkylene oxides and carbon dioxide onto H-functional starter substances using catalysts has been known for a long time. Various catalyst systems can be used here: The first generation represented heterogeneous zinc or aluminum salts, as described, for example, in US Pat. No. 3,900,424 or US Pat. No. 3,953,383. Furthermore, mono- and binuclear metal complexes have been used successfully for the copolymerization of CO 2 and alkylene oxides (WO 2010/028362, WO 2009/130470, WO 2013/022932 or WO 2011/163133). The most important class of catalyst systems for the copolymerization of carbon dioxide and alkylene oxides are the double metal cyanide catalysts, also referred to as DMC catalysts (US-A 4500704, WO 2008/058913). Suitable alkylene oxides and H-functional starter substances are those which are also used for the preparation of carbonate-free polyether polyols, as described above.

Polyols based on renewable raw materials "Natural oil-based polyols" (NOPs) for the production of PU foams are limited in view of their long-term availability fossil resources, namely oil, coal and gas, and against the background of rising crude oil prices of increasing interest and already widely described in such applications (WO 2005/033167; US 2006/0293400, WO 2006/094227, WO 2004/096882, US 2002/ 0103091, WO 2006/116456 and EP 1678232). A number of these polyols from various manufacturers are now available on the market (WO 2004/020497, US 2006/0229375, WO 2009/058367). Depending on the basic raw material (e.g. soybean oil, palm oil or castor oil) and the subsequent processing, polyols with different properties result. A distinction can essentially be made here between two groups: a) polyols based on renewable raw materials which are modified to such an extent that they can be used 100% for the production of polyurethanes (WO 2004/020497, US 2006/0229375); b) polyols based on renewable raw materials which, due to their processing and properties, can only replace the petrochemical-based polyol to a certain extent (WO 2009/058367).

The so-called packed polyols (polymer polyols) represent a further class of usable polyols. These are characterized in that they contain solid organic fillers up to a solids content of 40% or more in disperse distribution. Among others, SAN, PHD and PIPA polyols can be used. SAN polyols are highly reactive polyols containing a dispersed styrene/acrylonitrile (SAN)-based copolymer. PHD polyols are highly reactive polyols which also contain polyurea in dispersed form. PIPA polyols are highly reactive polyols containing a polyurethane in dispersed form, e.g., formed by the in situ reaction of an isocyanate with an alkanolamine in a conventional polyol.

A further class of polyols which can be used are those which are obtained as prepolymers by reacting polyol with isocyanate in a molar ratio of preferably 100:1 to 5:1, preferably 50:1 to 10:1. Such prepolymers are preferably prepared as a solution in the polymer, with the polyol preferably corresponding to the polyol used to produce the prepolymers.

Another class of polyols that can be used are so-called recycling polyols, ie polyols that are obtained from the recycling of polyurethanes. Recycling polyols are known per se. In this way, polyurethanes can be split by solvolysis and thus brought into a soluble form. Almost all chemical recycling processes for polyurethanes use such reactions, e.g. B. glycolysis, hydrolysis, acidolysis or aminolysis, with a variety of process variants known in the art are. The use of recycling polyols represents a preferred embodiment of the invention.

A preferred ratio of isocyanate and polyol, expressed as the formulation index, i.e. as 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, preferred 40 to 400. An index of 100 represents a molar ratio of the reactive groups of 1 to 1.

One or more organic polyisocyanates having two or more isocyanate functions are preferably used as isocyanate components or polyisocyanate components c). One or more polyols having two or more isocyanate-reactive groups, preferably OH groups, are preferably used as polyol components.

Isocyanates suitable as isocyanate components for the purposes of this invention are all isocyanates which contain at least two isocyanate groups. In general, all aliphatic, cycloaliphatic, arylaliphatic and preferably aromatic polyfunctional isocyanates known per se can be used. Isocyanates are particularly preferably used in a range from 40 to 400 mol % relative to the sum of the isocyanate-consuming components.

Examples which may be mentioned here are alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical, such as 1,12-dodecane diisocyanate, 2-ethyltetramethylene 1,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, tetramethylene 1,4-diisocyanate and preferably hexamethylene diisocyanate -1,6 (HMDI), cycloaliphatic diisocyanates such as cyclohexane-1,3- and 1-4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,35-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI for short), 2,4- and 2,6-hexahydrotoluylene 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, naphthalene diisocyanate, diethyltoluene diisocyanate, mixtures of 2 ,4'- and 2,2'-diphenylmethane diisocyanates (MDI) and polyphenylpolymethylene polyisocyanates (crude MDI) and mixtures of crude MDI and toluene diisocyanates (TDI). The organic di- and polyisocyanates can be used individually or in the form of their mixtures. Corresponding “oligomers” of the diisocyanates can also be used (IPDI trimer based on isocyanurate, biurete-urethdione.) It is also possible to use prepolymers based on the isocyanates mentioned above. It is also possible to use isocyanates which have been modified by the incorporation of urethane, uretdione, isocyanurate, allophanate and other groups, so-called modified isocyanates. Particularly suitable organic polyisocyanates and therefore particularly preferably used are various isomers of toluene diisocyanate (2,4- and 2,6-toluene diisocyanate (TDI), in pure form or as isomer mixtures of different composition), 4,4'-diphenylmethane diisocyanate (MDI), that so-called "crude MDI" or "polymeric MDI" (contains not only the 4,4'- but also the 2,4'- and 2,2'-isomers of MDI and polynuclear products) as well as the binuclear product referred to as "pure MDI". from predominantly 2,4'- and 4,4'-isomer mixtures or their prepolymers. Examples of particularly suitable isocyanates are listed, for example, in EP 1712578, EP 1161474, WO 00/58383, US 2007/0072951, EP 1678232 and WO 2005/085310, to which reference is made here in its entirety. d) catalysts

Suitable catalysts d) for the purposes of the present invention are all compounds which are able to accelerate the reaction of isocyanates with OH functions, NH functions or other isocyanate-reactive groups. The usual catalysts known from the prior art can be used here, including, 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, mixtures of several components can be used as catalysts.

Foam stabilizers can be used as optional component e), in particular surface-active silicon-containing compounds. These can optionally be used to further optimize the desired cell structure and the foaming process. Within the scope of this invention, it is possible in particular to use all Si-containing compounds which support foam production (stabilization, cell regulation, cell opening, etc.). These compounds are well known from the prior art. At least one foam stabilizer based on a polyethersiloxane can particularly preferably be used.

Corresponding siloxane structures that can be used for the purposes of this invention are described, for example, in the following patent specifications, although the use there is only in classic PU foams, as molded foam, mattresses, insulation material, construction foam, etc.:

CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008/0125503, US 2015/0057384, EP 1520870 A1, EP 1211279, EP 0867465, EP 0275563. of the disclosure of the present invention.

The use of blowing agents f) is basically optional, preferably obligatory, depending on which foaming process is used. Chemical and physical blowing agents can be used. The choice of propellant depends heavily on the type of system.

Depending on the amount of blowing agent used, a high or low density foam is produced. In this way, foams with densities of 5 kg/m ³ to 900 kg/m ³ can be produced. Preferred densities are 5 to 350, particularly preferably 10 to 200 kg/m ³ , in particular 20 to 150 kg/m ³ .

Corresponding compounds with suitable boiling points can be used as physical blowing agents. Chemical blowing agents that react with NCO groups and release gases, such as water or formic acid, can also be used. Particularly preferred blowing agents for the purposes of this invention include hydrocarbons having 3, 4 or 5 carbon atoms, hydrofluoroolefins (HFO), hydrohaloolefins and/or water.

Solid flame retardants g) have already been described above.

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

As optional liquid flame retardants, the composition according to the invention can have all known liquid flame retardants suitable for the production of polyurethane foams. Suitable optional liquid flame retardants within the meaning of this invention are preferred liquid organic phosphorus compounds such as halogen-free organic phosphates, e.g. triethyl phosphate (TEP), halogenated phosphates, e.g. tris(1-chloro-2-propyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) and/or organic phosphonates, eg dimethyl methane phosphonate (DMMP) or dimethyl propane phosphonate (DMPP). Furthermore, optionally usable liquid flame retardants are halogenated compounds, for example halogenated polyols.

The objects according to the invention have been and will be described below by way of example, without the invention being restricted to these exemplary embodiments. If ranges, general formulas or compound classes are given, they should not only include the corresponding ranges or groups of compounds that are explicitly mentioned, but also all sub-ranges and sub-groups of compounds that are obtained by removing individual values (ranges) or compounds be able. If documents are cited in the context of the present description, their content, in particular with regard to the facts in which the document was cited, should belong entirely to the disclosure content of the present invention. Unless otherwise stated, percentages are percentages by weight. If mean values are given, they are weight averages unless otherwise stated. If parameters are given that were determined by measurement, the measurements were carried out at a temperature of 25 °C and a pressure of 101,325 Pa, unless otherwise stated.

The present invention is described by way of example in the examples listed below, without the invention, the scope of which results from the entire description and the claims, being restricted to the embodiments mentioned in the examples.

Examples:

Example 1: Sedimentation Stability

The formulations shown in Table 2 were used for the performance comparison. For this purpose, 100 g of polyol, depending on the example, catalysts, water and foam stabilizer were weighed out and mixed with a plate stirrer (6 cm diameter) at 1000 rpm for 30 s. The compound according to the invention was then added and mixed with a plate stirrer (6 cm diameter) at 2000 rpm for 30 s. For the reference experiment, mixing was also carried out for a further 30 s at 2000 rpm, but without adding the compound according to the invention. Ammonium polyphosphate was then added as a solid flame retardant, with the plate stirrer still running at 2000 rpm, and mixed for a further 45 s. The formulations were then filled into glass vessels, sealed and the time taken for complete sedimentation was measured.

Table 2: Formulations (composition in parts by weight)

*Daltolac® R 471 from Huntsman,

**Stepanpol® PS 3152 from Stepan, ***lsoexter® 4973 from Coim,

* Catalysts from Evonik Operations GmbH ^m polyethersiloxane-based foam stabilizer from Evonik Operations GmbH

An ester quat (EQ 1) obtainable by reacting diisopropanolmethylamine with isostearic acid and oleic acid and subsequent methylation with dimethyl sulfate was used as the compound according to the invention. Table 3: Sedimentation stability

In all cases, a significant improvement in sedimentation stability was achieved compared to the formulation without esterquat.

Example 2: Redispersibility

For the performance comparison, it was checked to what extent the formulations described in Example 1 can be redispersed again. For this purpose, all formulations were stored upright at room temperature for 14 days until the solid had completely sedimented in all of them. All samples were then redispersed and rated on a scale of 1 to 3. The grade 1 means that the sample could already be brought back into dispersion by manually shaking the glass vessel for 30 s. The grade 2 means that the sample could not be redispersed by shaking it by hand, but could be redispersed again by using an electric laboratory stirrer (500 rpm for 60 s). Grade 3 was awarded to samples in which a very solid, compact sediment formed that could not be redispersed using the two methods just mentioned.

Table 4: Redispersibility

In all the cases investigated, a clear improvement in redispersibility could be achieved with the compound according to the invention. Especially when using polyester polyols, the formation of a solid, compact sediment could be avoided.

The invention therefore enables very good redispersibility of the solid in the event of sedimentation after very long storage, so that constant stirring or mixing during storage, for example, is no longer necessary.

Example 3: Viscosity

The influence of the compound according to the invention on the viscosity was examined for the application-related comparison of the processability. A polyester polyol from Stepan (Stepanpol® PS 2352) was selected as the base polyol. The formulations described in Table 5 were prepared analogously to the description in Example 1. The compound EQ 1 according to the invention described in Example 1 was selected as the ester quat. A TEGO® Dispers 1010 from Evonik Operations GmbH was selected as the reference additive for dispersing. The viscosity was measured using an Anton Paar MCR 302 rheometer (50 mm plate-plate, 0.5 mm distance) at 25° C. at various shear rates. Table 5: Viscosity (parts APP and EQ 1 based on 100 parts polyol)

The use of the ester quat according to the invention increases the viscosity only moderately at low shear rates, while conventional dispersing additives result in a sharp increase in viscosity. At higher shear rates, a significant reduction in viscosity can be achieved compared to conventional dispersing additives. In the present example, a viscosity on the level of the base polyol is even achieved. This brings clear advantages in processing and storage with regard to the requirements of the process technology.

Example 4: PIR rigid foam (PIR = polyisocyanurate)

The following foam formulation was used for the application-related comparison:

Table 6: PIR rigid foam formulation

*Stepanpol® PS 3152 from Stepan, OH number 315 mg KOH/g **POLYCAT® 5 from Evonik Operations GmbH ***KOSMOS® 75 from Evonik Operations GmbH

****TEGOSTAB® B 84504 from Evonik Operations GmbH *****p _0| Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

The comparative foamings were carried out using the hand mixing method. For this purpose, polyol, catalysts, water, foam stabilizer, optionally Esterquat EQ 1, ammonium polyphosphate and blowing agent were weighed into a beaker and mixed with a plate stirrer (6 cm diameter) at 1000 rpm for 30 s (batch size 500 g). The amount of propellant evaporated during the mixing process was determined by weighing again and replenished. The MDI was then added, the reaction mixture was stirred with the described stirrer for 5 s at 3000 rpm and immediately transferred to an aluminum mold measuring 25 cm×50 cm×7 cm and thermostated at 60° C. and lined with polyethylene film.

After 10 minutes, the foams were removed from the mold. The foams were analyzed one day after foaming. Surface and interior defects were assessed subjectively on a scale from 1 to 10, with 10 representing an (idealized) undisturbed foam and 1 representing an extremely severely disturbed foam. The thermal conductivity (l- Value in mW/mK) was measured on 2.5 cm thick discs using a Hesto Lambda Control, model HLC X206, at an average temperature of 10°C, in accordance with the specifications of the EN12667:2001 standard. The fire behavior was determined using the small burner test (B2) in accordance with DIN 4102-1:1998-05.

The results are summarized in the following table:

Table 7: PIR rigid foam The results show that the relevant foam properties are not or only insignificantly influenced by the compounds according to the invention. In addition, by using the compounds according to the invention, a more homogeneous distribution of the solid flame retardant in the foam can be achieved, which is expressed in a significant improvement in the surface and in the pore structure/internal defects.

Example 5: Behavior of other compounds according to the invention

Analogously to the procedure described in Examples 1 to 4, further compounds according to the invention were compared with those not according to the invention.

The formulation shown in Table 8 was used for the performance comparison

Table 8: PIR rigid foam formulation

*Stepanpol® PS 3152 from Stepan, OH number 315 mg KOH/g **POLYCAT® 5 from Evonik Operations GmbH

***DABCO® TMR 12 from Evonik Operations GmbH

****TEGOSTAB® B 84504 from Evonik Operations GmbH

*****p0 _| Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

The compounds shown in Table 9 were examined.

Table 9: Compounds studied The compounds according to the invention were compared with non-inventive, commercially available surfactants (TEGOPREN® 6921, TEGOTEX® 8080, TEGO® Dispers 652, Thixatrol® ST). The results shown in Table 10 with regard to the foam properties were obtained analogously to the procedure described in Example 4.

Table 10: Foam properties of PIR rigid foam The results show that the relevant foam properties are not or only insignificantly influenced by the compounds according to the invention. By using the compounds according to the invention, a more homogeneous distribution of the solid flame retardant in the foam can also be achieved, which results in a significant Improvement of the surface as well as the pore structure/internal disturbances. The compounds not according to the invention, on the other hand, lead to a strong coarsening of the foam (TEGOPREN® 6921), to collapse (TEGOTEX® 8080) or show no improvement in the foam structure (TEGO® Dispers 652, Thixatrol® ST).

The results shown in Table 11 with regard to sedimentation stability, redispersibility and viscosity were obtained analogously to the procedure described in Examples 1 to 3. The formulation described in Table 8 (without MDI, without cyclo/isopentane) was used to determine the sedimentation stability and redispersibility. A formulation of 10 parts of APP, 0.5 part of dispersing additive and 100 parts of polyester polyol (Stepanpol® PS 3152) was prepared as described in example 1 to determine the viscosity. The viscosity was determined analogously to example 3.

Table 11: Dispersing behavior

In all cases investigated, an improvement in sedimentation stability and redispersibility compared to formulations without compounds according to the invention or compared to surfactants not according to the invention was achieved.

Especially when using polyester polyols, the formation of a solid, compact sediment could be avoided.

The use of the compounds according to the invention increases the viscosity only moderately at low shear rates, while compounds not according to the invention result in a sharp increase in viscosity and therefore make processing more difficult.

Claims

Patent Claims:

1. Composition for the production of PU rigid foam, comprising at least one polyisocyanate component, at least one polyol component, blowing agent, solid flame retardant, optionally a catalyst which catalyzes the formation of a urethane or isocyanurate bond, characterized in that the composition has at least one Surfactant based on a quaternary ammonium compound contains.

2. Composition according to Claim 1, characterized in that the quaternary ammonium compound used is at least one ester quat of the formula (1) or (2), an alkyl quat of the formula (3), an imidazolinium quat of the formula (4), an amidoamine quat of the formula (5) and/or cetylpyridinium chloride is used, where with R ¹ being an acyl radical of a saturated or mono- or polyunsaturated, linear or branched fatty acid with a chain length of 8 to 22 carbon atoms or the acyl radical of ricinoleic acid, or hydrogen, where a compound of the formula (1) or (2) has different radicals R ¹ may contain and with the proviso that at least one radical R ¹ must be one of the acyl radicals mentioned, with R ² being an alkyl radical having 1 to 6 carbon atoms or hydrogen, preferably hydrogen, methyl, ethyl, propyl or isopropyl, particularly preferably hydrogen or methyl, R ³ is an alkyl radical having 1 to 6 carbon atoms or hydrogen, preferably hydrogen, methyl, ethyl, propyl or isopropyl, particularly preferably methyl or hydrogen, R ⁴ is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, preferably methyl, ethyl , propyl or isopropyl, particularly preferred

Ethyl or methyl, very particularly preferably methyl, where a compound of the formula (1) or (2) can contain different radicals R ⁴ and where n=0 to 20, preferably 0 to 10, particularly preferably 0, where a=1 to 3 and b = 1 to 3, with the proviso that a + b = 4, and/or where

( ^Ri formula (3) with R ⁵ is a saturated or mono- or polyunsaturated, linear or branched alkyl radical with a chain length of 8 to 24 carbon atoms, where a compound of formula (3) can contain different radicals R ⁵ , with R ⁶ an alkyl radical with 1 to 6 carbon atoms or a hydroxyethyl radical or a benzyl radical or hydrogen, preferably methyl, ethyl, propyl, isopropyl or benzyl, particularly preferably ethyl or methyl, very particularly preferably methyl, where a compound of the formula (3) can contain different R ⁶ radicals and where c = 1 to 3 and d = 1 to 3, with the proviso that c + d = 4, and/or where Formula (4) where R ⁷ is an alkyl radical having 1 to 6 carbon atoms or a hydroxyethyl radical or hydrogen, preferably methyl, ethyl, propyl or isopropyl, particularly preferably ethyl or methyl, very particularly preferably methyl, with R ⁸ is a saturated or mono- or polyunsaturated, linear or branched alkyl radical with 8 to 22 carbon atoms or a radical 0(CO)R ¹ °, with R ¹⁰ an aliphatic, saturated or mono- or polyunsaturated, linear or branched alkyl radical with 7 up to 21 carbon atoms, where R ⁹ is an aliphatic, saturated or mono- or polyunsaturated, linear or branched alkyl radical having 7 to 21 carbon atoms, where Z is an NH group or oxygen, where e can assume integer values between 1 and 4, with R ¹¹ is a saturated or mono- or polyunsaturated, linear or branched alkyl radical with a chain length of 7 to 21 carbon atoms, with R ¹² is an alkyl radical with 1 to 6 carbon atoms or a hydroxyethyl radical or

Hydrogen, preferably methyl, ethyl, propyl or isopropyl, particularly preferably ethyl or methyl, very particularly preferably methyl, where a compound of the formula (5) can contain different radicals R ¹² and where f can assume integer values between 0 and 5, where h = 1 or 2 and g = 2 or 3, with the proviso that h + g = 4, where a compound of formula (5) for h = 2 can assume different values for f and can contain different radicals R ¹¹ , provided that R ⁴ , R ⁶ , R ⁷ or R ¹² comprises a hydroxyethyl radical, this can also be alkoxylated and this optionally alkoxylated hydroxyethyl radical can contain repeating units based on ethylene oxide, propylene oxide, butylene oxide and/or styrene oxide and 1-15 repeating units, preferably 1-10 repeating units , include.

3. Composition according to claim 2, characterized in that in formula (1) and/or formula (2) R ¹ is selected from the acyl radicals of the acids from the group

Oleic acid, isostearic acid, lauric acid, palmitic acid, elaidic acid, vaccenic acid, gadoleic acid, icosenoic acid, cetoleic acid, erucic acid, nervonic acid, linoleic acid, alpha-linolenic acid, gamma-linolenic acid, calendulic acid, punicic acid, alpha- elaeostearic acid, beta-elaeostearic acid, arachidonic acid, timnodonic acid, clupanodonic acid and/or cervonic acid.

4. The composition according to claim 2 or 3, characterized in that in formula (1) a=b=2 and/or in formula (5) h=1 and g=3.

5. Composition according to at least one of claims 2 to 4, additionally containing at least one counter-anion to the compounds of the general formulas (1), (2), (3), (4) and/or (5) selected from the group consisting of chloride , bromide, iodide, alkyl sulphate, e.g., methyl sulphate, ethyl sulphate, alkyl sulphonate, e.g., methyl sulphonate, triflate, tosylate, phosphate, sulphate, hydrogen sulphate, lactate, glycolate, acetate and/or citrate.

6. Composition according to any one of claims 1 to 5, characterized in that the surfactant based on a quaternary ammonium compound in a total amount of 0.1 to 10 parts, preferably 0.1 to 5 parts, particularly preferably 0.1 to 4 parts, based on 100 parts of polyols.

7. The composition as claimed in any of claims 1 to 6, characterized in that the composition comprises ammonium polyphosphate, melamine, melamine cyanurate and/or red phosphorus, particularly preferably ammonium polyphosphate, as the solid flame retardant.

8. Composition according to any one of claims 1 to 7, characterized in that the composition contains ammonium polyphosphate and melamine or ammonium polyphosphate with a melamine coating or melamine shell or ammonium polyphosphate microencapsulated by means of melamine or melamine-formaldehyde resin as solid flame retardant.

9. Composition according to any one of claims 1 to 8, characterized in that the solid flame retardant is contained in a total amount of 1 to 60 parts, preferably 5 to 50 parts, particularly preferably 8 to 30 parts, based on 100 parts of polyols.

10. The composition as claimed in any of claims 1 to 9, characterized in that it additionally contains at least one foam stabilizer, in particular based on a polyethersiloxane, in amounts of 0.5 to 4 parts, based on 100 parts of polyols.

11. Process for the production of PU rigid foams based on foamable reaction mixtures containing polyisocyanates, at least one polyol component, blowing agent, solid flame retardant, optionally a catalyst and optionally further additives, characterized in that at least one surfactant based on a quaternary ammonium compound, preferably such as as defined in any one of claims 2 to 5, in particular using a composition as defined in any one of claims 1 to 10.

12. PU rigid foam produced by the process of claim 11.

13. Use of PU rigid foam according to claim 12 as insulating material and/or as a construction material, in particular in construction applications, in particular in spray foam or in the cooling area, as acoustic foam for sound absorption, as packaging foam, as headliner for automobiles or pipe sheathing for pipes.

14. Use of surfactants based on quaternary ammonium compounds, in particular as defined in any of claims 2 to 5, as a dispersing additive in the production of rigid PU foams containing solid flame retardants, in particular using a composition as claimed in any of claims 1 to 10.

15. Use of surfactants based on quaternary ammonium compounds to improve the dispersibility, redispersibility and / or

Sedimentation stability of solid flame retardants in compositions for the production of PU rigid foam, in particular according to claim 14.