Production of polyurethane foams

Abstract

Described is a composition for producing rigid polyurethane foam comprising at least one isocyanate component, a polyol component, optionally a catalyst for the formation of catalytic urethane or isocyanurate linkages, characterized in that the composition has as blowing agent a hydrocarbon having 3, 4 or 5 carbon atoms; a hydrofluorocarbon; a hydrofluoroolefin (HFO); a hydrohaloolefin; an oxygen-containing blowing agent and / or a hydrochlorocarbon, and further comprises as foam stabilizer an acrylic ester and / or methacrylic ester copolymer.

Description

TECHNICAL FIELD

[0001] The present invention is in the field of polyurethane foams. In particular, the present invention relates to the production of rigid polyurethane foams using specific blowing agents and acrylate and / or methacrylate copolymers as foam stabilizers. The present invention also relates to the corresponding compositions, and the use of the foams produced according to the present invention. The polyurethane foams are especially rigid polyurethane foams. BACKGROUND

[0002] Polyurethane (PU) in the context of the present invention is understood to mean especially the products obtainable by the reaction of polyisocyanates with polyols or compounds having isocyanate-reactive groups. In addition to polyurethanes, other functional groups can also be formed in the reaction, such as uretdiones, carbodiimides, isocyanurates, allophanates, biurets, ureas and / or uretonimines. For the purposes of the present invention, PU is therefore understood to mean not only polyurethanes but also polyisocyanurates, polyureas and polyisocyanate reaction products containing uretdione, carbodiimide, allophanate and uretonimine groups. In the context of the present invention, polyurethane foam (PU foam) is understood to mean a foam obtained as a reaction product based on polyisocyanates with polyols or compounds having isocyanate-reactive groups. In addition to the homonymous polyurethanes, other functional groups can also be formed, such as allophanates, biurets, ureas, carbodiimides, uretdiones, isocyanurates or uretonimines. The most preferred foam in the context of the present invention is a rigid polyurethane foam.

[0003] Polyurethane and polyisocyanurate foams, especially the corresponding rigid foams, are produced using additives which stabilize the cells or stabilize the foam in order to ensure a fine-cellular, uniform and few-defect foam structure, which has a substantially positive influence on the performance characteristics, such as in particular the thermal insulation properties of rigid foams. Surfactants based on polyether-modified siloxanes are particularly effective and therefore represent a preferred type of foam stabilizer.

[0004] Various publications have been published in connection with the use of siloxane-based additives. Polyether siloxane foam stabilizers (PES) are generally used in this connection.

[0005] EP 0570174 B1 describes polyether siloxanes which are suitable for the production of rigid polyurethane foams using organic blowing agents, in particular chlorofluorocarbons such as CFC-11.

[0006] EP 0 533 202 A1 describes polyether siloxanes with SiC-bonded polyalkylene oxide groups and which are suitable as blowing agents in the case of the use of hydrochlorofluorocarbons, such as HCFC-123.

[0007] EP 0 877 045 B1 describes similar structures for this production process, which differ from the previous foam stabilizers in that they have a relatively high molecular weight and have a combination of two polyether substituents on the siloxane chain.

[0008] EP 1544235 describes a typical polyether-modified siloxane for rigid PU foam applications. Here siloxanes with 60 to 130 silicon atoms and different polyether substituents R are used, which have a mixed molar mass of 450 to 1000 g / mol and an ethylene oxide content of 70 to 100 mol%.

[0009] CN 103055759 describes polyether-modified siloxanes which bring about improved cell opening. There are at least 18 silicon units in the siloxane, and various types of side chains are used for the modification.

[0010] EP 1873209 describes polyether-modified siloxanes for the production of rigid PU foams with improved fire protection properties. There are 10 to 45 silicon atoms in the siloxane here, and the polyether side chains consist to an extent of at least 90% of ethylene oxide units.

[0011] EP 2465891 A1 describes polyether-modified siloxanes in which some of the polyether side chains carry OH groups. The siloxanes here contain at least 10 silicon atoms.

[0012] EP 2465892 A1 describes polyether-modified siloxanes in which the polyether side chains carry mainly secondary OH end groups, wherein the siloxanes here also contain at least 10 silicon atoms.

[0013] DE 3234462 describes siloxanes for soft foams, in particular molded soft foams. A combination of polyether-modified siloxanes (PES) and polydimethylsiloxanes is described here, wherein the PES contains 4 to 15 silicon units.

[0014] Despite this, there is still a need for further foam stabilizers for PU foams, preferably for rigid PU foams, in particular those which fundamentally enable the stabilization of siloxane-free foams.

[0015] It is therefore a particular object of the present application to be able to provide rigid PU foams, wherein the foams can fundamentally be stabilized without siloxanes. SUMMARY

[0016] Surprisingly, it has now been found that by the combined use of specific blowing agents and acrylate and / or methacrylate copolymers as foam stabilizers, it is possible to produce rigid PU foams of impeccable quality. The blowing agents which can be used according to the application are hydrocarbons having 3, 4 or 5 carbon atoms; hydrofluorocarbons; hydrofluoroolefins (HFO); hydrohaloolefins; oxygen-containing blowing agents and / or hydrochlorocarbons.

[0017] The combination of blowing agents and acrylate and / or methacrylate copolymers as foam stabilizers according to the application fundamentally enables the stabilization of silicone-free foams, i.e. the combination enables the complete omission of silicone-based additives, such as the known polyether siloxane foam stabilizers. However, they also allow the joint use with the known silicone-containing stabilizers of the prior art. Both are encompassed in the present application.

[0018] In this context, the present application relates to a composition for producing rigid polyurethane foams, comprising at least one isocyanate component, a polyol component, optionally a catalyst for the catalytic formation of urethane or isocyanurate bonds, wherein the composition has as blowing agent a hydrocarbon having 3, 4 or 5 carbon atoms; a hydrofluorocarbon; a hydrofluoroolefin (HFO); a hydrohaloolefin; an oxygen-containing blowing agent and / or a hydrochlorocarbon and further comprises as foam stabilizer an acrylate and / or methacrylate copolymer.

[0019] The subject matter of the present application can provide rigid PU foams which are free of the known silicone-containing stabilizers. Nevertheless, the resulting PU foams meet the known requirements. They are advantageously dimensionally stable, hydrolysis-stable and have excellent long-term properties. They are advantageously of very good insulating properties, very high insulating capacity, high mechanical strength, high stiffness and high compressive strength. The subject matter of the present application can also provide rigid PU foams which are used in combination with the known silicone-containing stabilizers of the prior art.

[0020] Acrylate and / or methacrylate copolymers have been known from the prior art.

[0021] If the acrylate and / or methacrylate copolymers used according to the application are based on at least one H2C=CR 1 -COOR 2 type comonomer and at least one H2C=CR 1 -COOR 3 type comonomer, wherein

[0022] R 1 may be -H or -CH3, wherein different comonomers having different R 1 substituents from one another can be present in one molecule,

[0023] R2 each independently can be a radical selected from saturated or unsaturated linear, cyclic or branched aliphatic or aromatic hydrocarbons having 1 to 25 carbon atoms, preferably methyl, ethyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, isodecyl, cyclohexyl, benzyl, phenyl, isobornyl or allyl, wherein different R 2 Different copolymerized monomers with different substituents can be present in one molecule,

[0024] R 3 each independently can be a radical selected from polyethers based on structure 1, wherein different R 3 Different copolymerized monomers with different substituents can be present in one molecule,

[0025]

[0026] wherein

[0027] x is 3 to 500, preferably greater than 5, in particular 8 to 100,

[0028] R 4 each independently can be a hydrogen radical or a radical selected from saturated or unsaturated linear, cyclic or branched aliphatic or aromatic hydrocarbons having 1 to 12 carbon atoms, in particular preferably -H, methyl, ethyl or styryl, wherein different R 3 substituents in the radicals R 4 can be present in any order or sequence,

[0029] R 5 is -CH2-O-, -CH2-CH2-O-, -CH2-CH2-CH2-O-, -CH2-CH2-CH2-CH2-O- or -CH2-CH2-CH2-CH2-CH2-O-, wherein R 5 can also be omitted,

[0030] R 6 each independently can be a hydrogen radical, a radical selected from saturated or unsaturated linear, cyclic or branched aliphatic or aromatic hydrocarbons having 1 to 25 carbon atoms, an acyl radical, a radical of the structure -CH2-CH(OH)-CH2OH or a radical of the structure -CH2-C(CH2OH)2-CH2-CH3, in particular preferably -H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, wherein different R 6 Different copolymerized monomers with different substituents can be present in one molecule,

[0031] This is a particularly preferred embodiment of the present application.

[0032] If the acrylate and / or methacrylate copolymer used according to the application has a number average molecular weight Mn in the range from 500 to 100 000 g / mol, particularly preferably from 1000 to 20 000 g / mol, which is determined by gel permeation chromatography according to DIN 55672-1 :2016-03 (eluent: THF; standard: PMMA), this is another particularly preferred embodiment of the application.

[0033] Acrylate and / or methacrylate monomers which can be used in the context of the present application are also commercially available, for example from Evonik Operations GmbH under the trade name VISIOMER.

[0034] Examples of these are, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenethyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, hydroxyalkyl (meth)acrylates such as 3-hydroxypropyl methacrylate, 3,4-dihydroxybutyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,5-dimethyl-1,6-hexanediol (meth)acrylate, 1,10-decanediol (meth)acrylate, glycol dimethacrylates such as 1,4-butanediol methacrylate, 2-butoxyethyl methacrylate, 2-ethoxyethoxymethyl methacrylate, 2-ethoxyethyl methacrylate, methacrylates of ether alcohols such as tetrahydrofurfuryl methacrylate, methacrylate ethylenoxylethoxyethyl, methacrylate methoxyethoxyethyl, 1 -butoxypropyl methacrylate, 1 -methyl-(2-ethylenoxyl)ethyl methacrylate, cyclohexyloxymethyl methacrylate, methoxy-methoxy-ethyl methacrylate, benzyl methacrylate, furfuryl methacrylate, 2-butoxyethyl methacrylate, 2-ethoxyethoxymethyl methacrylate, 2-ethoxyethyl methacrylate, allyloxy-methyl methacrylate, 1 -ethoxybutyl methacrylate, methoxy-methyl methacrylate, 1 -ethoxyethyl methacrylate, ethoxymethyl methacrylate and preferably ethoxylated or propoxylated (meth)acrylates having from 1 to 20, in particular from 2 to 8, ethoxy or propoxy groups.

[0035] The expression "(meth)acrylate" refers herein to both methacrylates (e.g. methyl methacrylate, ethyl methacrylate, etc.) and acrylates (e.g. methyl acrylate, ethyl acrylate, etc.) as well as mixtures of both.

[0036] Furthermore, processes for preparing useful acrylate and / or methacrylate copolymers are known from the prior art and are described, for example, in EP 1 070 730 or US 9 349 500 B2.

[0037] In principle, compounds which decompose into free radicals under the polymerization conditions can be used as initiators, such as, for example, peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds and so-called redox initiators. In some cases, it can also be advantageous to use mixtures of different initiators, such as, for example, hydrogen peroxide and sodium peroxodisulfate or mixtures of sodium peroxodisulfate. Organic peroxides are, for example, acetylacetone peroxide, methyl ethyl ketone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-amyl perpivalate, tert-butyl perpivalate, tert-butyl perneohexanoate, tert-butyl perisobutyrate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl perisononanoate, tert-butyl permaleate, tert-butyl perbenzoate, di(2-ethylhexyl) peroxydicarbonate, dicyclohexyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, dimyristyl peroxydicarbonate, diacetyl peroxydicarbonate, allyl peresters, cumyl perisononate, tert-butyl peroxy-3,5,5-trimethylhexanoate, acetylcyclohexylsulfonyl peroxide, dilauryl peroxide and tert-amyl peroxy-2-ethylhexanoate. Other initiators are azo compounds, such as, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile) and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile).

[0038] Surprisingly, it has been found in the context of the present application that the acrylate and / or methacrylate copolymer according to the present application should preferably be produced using tert-butyl peroxy-2-ethylhexanoate (TBPEH) or tert-amyl peroxy-2-ethylhexanoate (APO) or a combination of TBPEH and APO as initiator, since even better results can be achieved in terms of the results sought according to the present application. In particular, however, acrylate and / or methacrylate copolymers produced using dibenzoyl peroxide (BPO) as initiator prove to be very disadvantageous and very unsuitable in terms of the concerns of the present application. Thus, when the acrylate and / or methacrylate copolymer used according to the present application is one that has not been produced using BPO as initiator, it corresponds to a particularly preferred embodiment of the present application.

[0039] Furthermore, when the acrylate and / or methacrylate copolymer has a residual monomer content of less than 1 %, it corresponds to a particularly preferred embodiment of the present application. The residual monomer content can be determined by customary methods; in particular, it can be determined via the solids content or by GC or HPLC. Suitable compositions enable particularly advantageous foams according to the present application, which are also particularly low in emissions.

[0040] In addition to the acrylate and / or methacrylate copolymer used as a foam stabilizer according to the present application, the particular blowing agent used according to the present application also includes hydrocarbons having 3, 4 or 5 carbon atoms; hydrofluorocarbons; hydrofluoroolefins (HFO); hydrohaloolefins; oxygen-containing blowing agents and / or hydrochlorocarbons.

[0041] Further, another particularly preferred embodiment of the present application is that the blowing agent used is a hydrocarbon having 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane and / or n-pentane; a hydrofluorocarbon, preferably HFC 245fa, HFC 134a and HFC 365mfc; a perfluorinated compound, such as perfluoropentane, perfluorohexane and / or perfluorohexene; a hydrofluoroolefin or a hydrohaloolefin, preferably 1234ze, 1234yf, 1224yd, 1233zd(E) and / or 1336mzz; an oxygen-containing compound, such as methyl formate, acetone and / or dimethoxymethane; and / or a hydrochlorocarbon, preferably dichloromethane and / or 1,2-dichloroethane.

[0042] Based on 100 parts by mass of the polyol component, if the mass proportion of the total amount of acrylate and / or methacrylate copolymer is 0.1 to 10 pphp, preferably 0.5 to 5 pphp and particularly preferably 1 to 4 pphp, this is again a preferred embodiment of the present application.

[0043] The present application can dispense with Si-containing foam stabilizers. In this case, a composition according to the application comprising less than 15 wt.-%, preferably less than 10 wt.-%, further preferably less than 5 wt.-%, more preferably less than 3 wt.-%, even more preferably less than 1 wt.-%, in particular less than 0.5 wt.-% of Si-containing foam stabilizer, if any, based on the total amount of foam stabilizer, is a preferred embodiment of the present application.

[0044] As mentioned above, the present application also additionally enables the parallel use of Si-containing foam stabilizers. In this case, a composition according to the application comprising more than 1 wt.-%, preferably more than 10 wt.-%, in particular more than 20 wt.-% of Si-containing foam stabilizer, based on the total amount of foam stabilizer, is a preferred embodiment of the present application. In the case of such an embodiment, mixtures of e.g. 50 wt.-%: 50 wt.-% are also possible; i.e. the composition will comprise equal parts of the acrylate and / or methacrylate copolymer used according to the application and Si-containing foam stabilizer. In fact, it has surprisingly been found that the acrylate and / or methacrylate copolymer used according to the application improves the emulsifying ability of the Si-containing foam stabilizer.

[0045] In principle, all foam stabilizing components known from the prior art can also be used in addition to the acrylate and / or methacrylate copolymer used according to the application.

[0046] The acrylate and / or methacrylate copolymer used according to the application can be used in pure form or in a solvent. In this case, all suitable substances which can be used for the production of PU foams can be used. The solvents used are preferably substances which have already been used in standard formulations, e.g. OH-functional compounds, polyols, flame retardants, etc.

[0047] Preferred compositions according to the application comprise the following ingredients:

[0048] a) an acrylate and / or methacrylate copolymer according to the application as described above,

[0049] b) at least one polyol component,

[0050] c) at least one polyisocyanate and / or polyisocyanate prepolymer,

[0051] d) optionally a catalyst which accelerates or controls the reaction of the polyol b) with the isocyanate c),

[0052] e) optionally further foam stabilizers, in particular corresponding silicon-containing compounds,

[0053] f) a blowing agent according to the application as described above,

[0054] g) optionally other additives, fillers, flame retardants, etc.

[0055] It is preferred here that component d) is necessary.

[0056] In a preferred embodiment of the present application, in addition to the acrylate and / or methacrylate copolymer according to the present application and the blowing agent according to the present application, a component having at least 2 isocyanate-reactive groups, preferably a polyol component, a catalyst and a polyisocyanate and / or a polyisocyanate prepolymer are used to produce a polyurethane foam. The catalyst is introduced here, inter alia, via the polyol component. Suitable polyol components, catalysts and polyisocyanates and / or polyisocyanate prepolymers are known to the person skilled in the art, but are described in more detail below.

[0057] For the purposes of the present application, polyols suitable as polyol component b) are all organic substances having two or more isocyanate-reactive groups, preferably OH groups, and formulations thereof. Preferred polyols are all polyether polyols and / or polyester polyols and / or hydroxyl-containing aliphatic polycarbonates, in particular polyether polycarbonate polyols, and / or polyols of natural origin known as "Natural Oil-based Polyols" (NOP), which are commonly used for the production of polyurethane systems, in particular polyurethane coatings, polyurethane elastomers or foams. The polyols generally have a functionality of 1.8 to 8 and a number-average molecular weight in the range from 500 to 15,000. Polyols having an OH number in the range from 10 to 1,200 mg KOH / g are generally used.

[0058] For the production of rigid PU foams, polyols or mixtures thereof can preferably be used, provided that at least 90 parts by weight of the polyols present have an OH number of greater than 100, preferably greater than 150, in particular greater than 200, based on 100 parts by weight of the polyol component. The fundamental difference between soft and rigid foams is that soft foams exhibit elastic properties and can be reversibly deformed. When soft foams are deformed by a force, they return to their original shape once the force is removed. In contrast, rigid foams deform permanently. This is well known to the person skilled in the art.

[0059] The polyether polyols can be obtained by known methods, for example by anionic polymerization of alkylene oxides in the presence of an alkali metal hydroxide, alkali metal alkoxide or amine as catalyst, and by addition of at least one starter molecule, which preferably contains 2 or 3 reactive hydrogen atoms in bonded form, 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 group. Examples are tetrahydrofuran, 1,3- propylene oxide, 1,2-butylene oxide and 2,3-butylene oxide; the use of ethylene oxide and 1,2-propylene oxide is preferred. The alkylene oxides can be used individually, cumulatively in blocks, in an alternating form or as a mixture. Styrene oxide is also suitable. The starter molecules used can be, inter alia, compounds having at least 2, preferably 2 to 8, hydroxyl groups or at least two primary amino groups in the molecule. The starter molecules used can be, for example, water; diols / triols or tetraols such as ethylene glycol, 1,2-propanediol and 1,3-propanediol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, castor oil and the like; higher polyfunctional polyols, in particular saccharide compounds, for example glucose, sorbitol, mannitol and sucrose; polyphenols; resols, for example oligomeric condensation products of phenol and formaldehyde and Mannich condensates of phenol, formaldehyde and dialkanolamines and melamine; or amines such as aniline, EDA, TDA, MDA and PMDA, more preferably TDA and PMDA. The choice of suitable starter molecules depends on the respective field of application of the resulting polyether polyol in polyurethane production.

[0060] The polyester polyols are based on esters of aliphatic or aromatic polycarboxylic acids, which preferably have 2 to 12 carbon atoms. Examples of aliphatic carboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid and fumaric acid. Examples of aromatic carboxylic acids are phthalic acid, isophthalic acid, terephthalic acid and isomeric naphthalene dicarboxylic acids. The polyester polyols are obtained by condensation of these polycarboxylic acids with polyols, which preferably have 2 to 12, more preferably 2 to 6, carbon atoms of diols or triols, preferably ethylene glycol, diethylene glycol, trimethylolpropane and glycerol.

[0061] Polyether polycarbonate polyols are polyols which contain carbon dioxide in the form of carbonate linkages. Since carbon dioxide is formed in large amounts as a by-product in many processes in the chemical industry, it is of particular interest from an industrial point of view to use carbon dioxide as a comonomer in the polymerization of alkylene oxides. The partial replacement of alkylene oxides in polyols by carbon dioxide makes it possible to significantly reduce the production costs of polyols. Furthermore, the use of CO2 as a comonomer is very advantageous for the environment since the reaction constitutes a conversion of a greenhouse gas into a polymer. The preparation of polyether polycarbonate polyols by the addition of alkylene oxides and carbon dioxide to H-functional starting materials using catalysts is already known. Various catalyst systems can be used here: the first generation are heterogeneous zinc or aluminum salts, for example as described in US-A 3900424 or US-A 3953383. In addition, mononuclear and binuclear metal complexes have been successfully used for the copolymerization of CO2 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 is the double metal cyanide catalyst system, also known as DMC catalyst (US-A 4500704, WO 2008 / 058913). Suitable alkylene oxides and H-functional starting materials are those also described above for the preparation of carbonate-free polyether polyols.

[0062] In view of the long-term availability constraints of fossil resources, i.e. oil, coal and natural gas, and against the background of rising crude oil prices, polyols for the production of polyurethane foams based on renewable raw materials, natural oil-based polyols (NOP), are increasingly gaining interest and have been described several times in such applications (WO 2005 / 033167, US 2006 / 0293400, WO 2006 / 094227, WO 2004 / 096882, US 2002 / 0103091, WO 2006 / 116456 and EP 1678232). Many of these polyols are now commercially available from different manufacturers (WO 2004 / 020497, US 2006 / 0229375 and WO 2009 / 058367). Depending on the base raw material (e.g. soybean oil, palm oil or castor oil) and subsequent processing, polyols with different properties are obtained. Basically two groups can be distinguished: a) polyols based on renewable raw materials which are modified in such a way that they can be used for the production of polyurethanes to the extent of 100% (WO 2004 / 020497, US 2006 / 0229375); b) polyols based on renewable raw materials which, due to their processing and properties, can only replace petroleum-based polyols to a certain extent (WO 2009 / 058367).

[0063] Another class of useful polyols are so-called filled polyols (polymeric polyols). One characteristic of these filled polyols is that they contain dispersed solid organic fillers, with a solids content of up to 40% or more. Useful polyols include SAN, PUD and PIPA polyols. SAN polyols are highly reactive polyols containing dispersed copolymers based on styrene-acrylonitrile (SAN). PUD polyols are highly reactive polyols containing polyureas also in dispersed form. PIPA polyols are highly reactive polyols containing dispersed polyurethanes, for example formed by in situ reaction of isocyanates with alkanolamines in the conventional polyol.

[0064] Another class of useful polyols are those obtained as prepolymers via reaction of a polyol with isocyanates in a molar ratio of preferably 100:1 to 5:1, more preferably 50:1 to 10:1. Such prepolymers are preferably made in the form of a solution in a polyol, which polyol preferably corresponds to the polyol used to make the prepolymer.

[0065] The preferred ratio of isocyanate to polyol, expressed as the factor of the formulation, i.e. the stoichiometric ratio of isocyanate groups to isocyanate reactive groups (e.g. OH groups, NH groups) multiplied by 100, is in the case of the present invention in the range of 10 to 1000, preferably 40 to 500. This corresponds to one preferred embodiment of the present invention. A factor of 100 means a molar ratio of reactive groups of 1 :1.

[0066] The isocyanate component c) used is preferably one or more organic polyisocyanates having two or more isocyanate functional groups. The polyol component used is preferably one or more polyols having two or more isocyanate reactive groups, preferably OH groups.

[0067] For the purposes of the present invention, isocyanates suitable as isocyanate component are all isocyanates containing at least two isocyanate groups. In general, all aliphatic, cycloaliphatic, araliphatic and preferably aromatic polyfunctional isocyanates known per se can be used. More preferably, isocyanates are used in the range of 60 to 200 mole %, relative to the sum of the components consuming isocyanate.

[0068] Specific examples are: alkylenediisocyanates having 4 to 12 carbon atoms in the alkylen moiety, such as dodecane-1,12-diisocyanate, 2-ethyltetramethylene 1,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, tetramethylene 1,4-diisocyanate and preferably hexamethylene 1,6-diisocyanate (HMDI), cycloaliphatic diisocyanates such as cyclohexane 1,3- and 1,4-diisocyanate and any mixture of these isomers, 1 -isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or simply IPDI), hexahydrotoluene 2,4- and 2,6-diisocyanate and the corresponding isomer mixtures, and preferably aromatic diisocyanates and polyisocyanates such as toluene 2,4- and 2,6-diisocyanate (TDI) and the corresponding isomer mixtures, naphthalene diisocyanate, diethyl toluene diisocyanate, diphenylmethane 2,4'- and 2,2'-diisocyanate (MDI) mixtures of polyphenyl polymethylene polyisocyanates (crude MDI) and mixtures of crude MDI and toluene diisocyanate (TDI). The organic diisocyanates and polyisocyanates can be used individually or in the form of mixtures thereof. It is likewise possible to use corresponding "oligomers" of the diisocyanates (IPDI trimer based on isocyanurate, biuret, uretdione). Furthermore, prepolymers based on the aforementioned isocyanates can be used.

[0069] It is also possible to use isocyanates modified by the introduction of urethane, uretdione, isocyanurate, allophanate and other groups, which are referred to as modified isocyanates.

[0070] Thus, particularly preferred organic polyisocyanates which are particularly suitable for use are the various isomers of toluene diisocyanate (toluene 2,4- and 2,6-diisocyanate (TDI), in pure form or as isomer mixtures of different composition), diphenylmethane 4,4'-diisocyanate (MDI), "crude MDI" or "polymeric MDI" (comprising the 4,4' isomer of MDI as well as the 2,4' and 2,2' isomers and products having more than two rings) and products having two rings which are referred to as "pure MDI" and consist mainly of a mixture of the 2,4' and 4,4' isomers, and prepolymers derived therefrom. Examples of particularly suitable isocyanates are described in detail, for example, in EP 1712578, EP 1161474, WO 00 / 58383, US 2007 / 0072951, EP 1678232 and WO 2005 / 085310, which are incorporated by reference in their entirety.

[0071] Suitable optional available catalysts d) in the context of the present application are all compounds which are able to accelerate the reaction of isocyanates with OH-functionalities, NH-functionalities or other isocyanate-reactive groups. In this context, conventional catalysts known from the prior art can be used, including for example amines (cyclic, acyclic; monoamines, diamines, oligomers with one or more amino groups), organometallic compounds and metal salts, preferably those of iron, bismuth and zinc. In particular, mixtures of various components can be used as catalysts.

[0072] It has been found that the composition according to the present application which does not comprise a tin-containing catalyst has proven to be particularly advantageous for achieving the results sought according to the present application. Thus, a composition according to the present application which is essentially free of tin-containing catalysts corresponds to a particularly preferred embodiment of the present application. This also applies to the process for producing rigid polyurethane foam described below. When essentially no tin-containing catalysts are used, this is also a preferred embodiment of the present application.

[0073] Component e) is an optional available further foam stabilizer which is not an acrylate and / or methacrylate copolymer according to the present application. They can preferably be silicon compounds for further optimizing the surface activity of the desired cell structure and foaming process. In the context of the present application, any silicon-containing compound which promotes the production of foam (stabilization, cell regulation, cell opening, etc.) can be used. These compounds are well known from the prior art. The surface-active silicon-containing compounds can be any known compound suitable for the production of PU foams.

[0074] Siloxane structures of this type which can be used in the context of the present application are described, for example, in the patent documents CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008 / 0125503, US 2015 / 0057384, EP 1520870 A1, EP 1211279, EP 0867464, EP 0867465, EP 0275563, although these patent documents describe only for conventional polyurethane foams, such as molding foams, mattress foams, insulating materials, construction foams, etc. These documents are hereby incorporated by reference and it is considered that these documents form part of the disclosure of the present application.

[0075] As explained above, the use of a blowing agent f) is mandatory. At least one blowing agent according to the present application must be used. If necessary, further blowing agents can additionally be used. Chemical and physical blowing agents can be used.

[0076] Depending on the total amount of blowing agent used, foams with high or low density are produced. For example, foams with a density of 5 kg / m 3 up to 900 kg / m 3of 8 to 800 kg / m3 3 , more preferably 10 to 600 kg / m3 3 , in particular 30 to 150 kg / m3 3 .

[0077] In principle, the physical blowing agent used can be a suitable compound having a suitable boiling point. In principle, it is also possible to use chemical blowing agents which react with the NCO groups and release a gas, such as water or formic acid. Examples of conventional blowing agents are liquefied CO2, nitrogen, air, highly volatile liquids.

[0078] The optional additives g) which can be used include all substances which are known in the prior art and which can be used for the production of polyurethanes, preferably PU foams, in particular rigid polyurethane foams, such as crosslinkers and chain extenders, stabilizers against oxidative degradation (referred to as antioxidants), flame retardants, surfactants, biocides, cell-refining additives, cell-openers, solid fillers, antistatic additives, nucleating agents, thickeners, dyes, pigments, color pastes, fragrances, emulsifiers and the like.

[0079] The flame retardants comprised in the composition according to the application can be any known flame retardant suitable for the production of polyurethane foams. Suitable flame retardants for the purposes of the present application are preferably liquid organic phosphorus compounds such as halogen-free organophosphates, for example triethyl phosphate (TEP); halogenated phosphates, for example tris(1 -chloro-2-propyl)phosphate (TCPP) and tris(2-chloroethyl)phosphate (TCEP); and organophosphonates, for example dimethyl methylphosphonate (DMMP), dimethyl propylphosphonate (DMPP); or solids such as ammonium polyphosphate (APP) and red phosphorus. Furthermore, halogenated compounds such as halogenated polyols and solids such as expandable graphite, aluminium oxide, antimony compounds and melamine are suitable as flame retardants. The use of the acrylate and / or methacrylate copolymers of the present application enables the use of very large amounts of flame retardants, in particular also liquid flame retardants, such as TEP, TCPP, TCEP, DMMP, which generally lead to relatively unstable formulations.

[0080] The present application also provides a process for producing rigid polyurethane foam by reacting one or more polyol components with one or more isocyanate components, wherein the reaction takes place in the presence of a blowing agent comprising a hydrocarbon having 3, 4 or 5 carbon atoms; a hydrofluorocarbon; a hydrofluoroolefin (HFO); a hydrohaloolefin; an oxygen-containing blowing agent and / or a hydrochlorofluorocarbon and in the presence of an acrylic and / or methacrylic ester copolymer as a foam stabilizer, especially using a composition according to the present application as described above. In order to avoid repetitions, reference is made in this respect to the preceding text. In particular with regard to preferred embodiments of the present application, reference is made to the preceding text. The acrylic and / or methacrylic ester copolymer according to the present application is used as a foam stabilizer.

[0081] The rigid PU foam produced according to the present application has a density of preferably 5 kg / m 3 to 900 kg / m 3 , more preferably 8 to 800 kg / m 3 , particularly preferably 10 to 600 kg / m 3 , more particularly 20 to 150 kg / m 3 .

[0082] More particularly, a closed-cell rigid PU foam can be obtained, wherein the closed-cell content is advantageously greater than 80 %, preferably greater than 90 %. This is a very particularly preferred embodiment of the present application. In the context of the present application, the closed-cell content is preferably determined by means of a pycnometer according to DIN ISO 4590:2016-4590.

[0083] The process according to the present application for producing rigid PU foam can be carried out by known methods, for example by hand mixing or, preferably, by means of a foaming machine. If the process is carried out using a foaming machine, a high-pressure machine or a low-pressure machine can be used. The process according to the present application can be carried out discontinuously or continuously.

[0084] The preferred rigid polyurethane or polyisocyanurate foam formulation according to the present application has a foam density of 5 to 900 kg / m 3 and has the composition shown in Table 1.

[0085] Table 1 : Composition of the preferred rigid polyurethane or polyisocyanurate foam formulation

[0086]

[0087] For further preferred embodiments and configurations of the process according to the present application, reference is also made to the details already given above with regard to the composition according to the present application, especially with regard to the preferred embodiments specified there.

[0088] The present application also provides the rigid PU foam obtainable by the process.

[0089] According to a further preferred embodiment of the present application, the rigid PU foam has a foam density of 5 to 900 kg / m3 3 , preferably 8 to 750 kg / m3 3 , particularly preferably 10 to 350 kg / m3 3 , in particular 20 to 150 kg / m3 3 , and the closed cell content is advantageously greater than 80 %, preferably greater than 90 %.

[0090] It is advantageous that the rigid polyurethane foams according to the present application are characterized in that they comprise at least one acrylate and / or methacrylate copolymer according to the present application, as described above, and can be obtained using a blowing agent according to the present application, preferably by a process according to the present application.

[0091] The PU foams (polyurethane or polyisocyanurate foams) according to the present application are rigid PU foams and can be used as or for the production of insulation materials, preferably insulation boards, refrigerators, insulation foams, vehicle seats, in particular car seats, headliners, mattresses, filter foams, packaging foams or spray foams.

[0092] The PU foams, in particular rigid PU foams, according to the present application can advantageously be used in particular in the cold storage warehouse, refrigeration appliance and household appliance industry, for example for the production of insulation boards for roofs and walls, as insulation material in containers and warehouses for frozen goods, and for refrigeration and freezing equipment.

[0093] A further preferred field of use is the vehicle construction, in particular for the manufacture of vehicle headliners, body parts, interior trim, cooled vehicles, large containers, transport pallets, packaging laminates, in the furniture industry (for example for furniture parts, doors, linings), in electronic applications.

[0094] The cooling equipment according to the present application has a rigid PU foam (polyurethane or polyisocyanurate foam) according to the present application as insulation material.

[0095] The present application also provides the use of rigid PU foams as insulation material in the refrigeration technology, refrigeration equipment, building sector, automotive sector, shipbuilding sector and / or electronics sector; as insulation boards; as spray foams; as one-component foams.

[0096] The present application also relates to the use of the composition according to the present application comprising an acrylate and / or methacrylate copolymer as described above as a foam stabilizer and comprising a blowing agent according to the present application as described above for providing rigid polyurethane foams having improved insulation properties.

[0097] The subject matter of the present application is described herein by way of examples above or below, without intending to limit the application to such illustrative embodiments. When ranges, general formulas or types of compounds are specified in the above or below, these are intended to include not only the respective ranges or sets of compounds explicitly mentioned, but also all sub-ranges and subsets of compounds that can be obtained by removing individual values (ranges). When a document is cited in the context of the present specification, the entire content of the document, in particular the content that forms the subject matter of the document cited, is intended to form part of the disclosure of the present application. Percentages are all percentages by weight, unless otherwise stated. When values are recorded in the above or below as averages, these are all weight averages, unless otherwise stated. When a parameter is given in the above or below that has been determined by measurement, this measurement has been carried out at a temperature of 25 °C and a pressure of 101325 Pa.

[0098] The following examples describe the application by way of example, but are not intended to limit the application to the embodiments specified in the examples, the scope of application of which is clearly derived from the entire specification and claims. DETAILED DESCRIPTION

[0099] Example:

[0100] Example 1 : Synthesis of copolymers A to F

[0101] Copolymer A:

[0102] In a 500 mL four-necked flask, equipped with a reflux condenser and a N2line, a Sabre stirrer (200 rpm) and a Pt100 digital internal thermometer, 30.01 g of n-butyl acetate were initially charged and the oil bath was heated to 145 °C. A mixture of 9.2 g of TBPEH (tert-butyl peroxy-2-ethylhexanoate), 56.18 g of isobutyl methacrylate (i-BMA), 67.29 g of MPEG500 methacrylate (MPEG500MA) and 2.21 g of 2-mercaptoethanol was metered in over 4 hours using a peristaltic pump. The mixture was stirred for a further 30 minutes at this temperature. The mixture was cooled to 80 °C, 0.13 g of TBPEH dissolved in 10 g of n-butyl acetate was metered in for the supplementary reaction and the mixture was stirred for a further 2 hours at 80 °C. A further 5 g of n-butyl acetate was added and the mixture was stirred for a further 30 minutes without heating.

[0103] GPC according to DIN 55672-1 :2016-03 (eluent: THF; standard: PMMA): Mw = 5630 g / mol; Mn = 2560 g / mol; PDI = 2.2.

[0104] Copolymer B:

[0105] In a 500 mL four necked flask, equipped with reflux condenser and N2 line, Sabre stirrer (200 rpm) and Pt 100 digital internal thermometer, 30.01 g n-butyl acetate was initially charged and the oil bath was heated to 145 °C. A mixture of 9.2 g TBPEH, 54.69 g IDMA, 68.77 g MPEG500MA and 2.21 g 2-mercaptoethanol was dosed over 4 hours using a peristaltic pump. The mixture was stirred for additional 30 minutes at this temperature. The mixture was cooled to 80 °C, 0.13 g TBPEH dissolved in 10 g n-butyl acetate was dosed for the make-up reaction and the mixture was stirred for additional 2 hours at 80 °C. Additional 5 g n-butyl acetate was added and the mixture was stirred for additional 30 minutes without heating.

[0106] GPC according to DIN 55672-1 :2016-03 (eluent: THF; standards: PMMA): Mw = 5250 g / mol; Mn = 2410 g / mol; PDI = 2.2.

[0107] Copolymer C:

[0108] In a 500 mL four necked flask, equipped with reflux condenser and N2 line, Sabre stirrer (200 rpm) and Pt 100 digital internal thermometer, 30.01 g n-butyl acetate was initially charged and the oil bath was heated to 145 °C. A mixture of 20.75 g BP-50-FT (BPO), 50.92 g iBMA, 60.99 g MPEG500MA and 2.21 g 2-mercaptoethanol was dosed over 4 hours using a peristaltic pump. The mixture was stirred for additional 30 minutes at this temperature. The mixture was cooled to 80 °C, 0.13 g BP-50-FT dissolved in 10 g n-butyl acetate was dosed for the make-up reaction and the mixture was stirred for additional 2 hours at 80 °C. Additional 5 g n-butyl acetate was added and the mixture was stirred for additional 30 minutes without heating.

[0109] GPC according to DIN 55672-1 :2016-03 (eluent: THF; standards: PMMA):

[0110] Mw = 6350 g / mol; Mn = 4080 g / mol; PDI = 1.6.

[0111] Copolymer D:

[0112] In a 1000 mL four necked flask equipped with reflux condenser and N2 line, Sabre stirrer (100 rpm) and Pt 100 digital internal thermometer, initially a mixture of 265.05 g of petroleum ether (boiling point 100-120 °C) and 265.05 g of toluene was charged and the oil bath was heated to 135 °C. A mixture of 4.43 g BP-50-FT, 90.59 g C17,4MA (stearyl methacrylate), 55.02 g MPEG350MA (MPEG350 methacrylate) and 19.06 g i-BMA was dosed using a peristaltic pump over 5 hours. After the dosing was completed, 0.40 g BP-50-FT was added for the make-up reaction and the mixture was stirred for another 2 hours. The mixture was cooled to room temperature and left in the flask overnight without stirring. The oil bath was heated to 130 °C again, 0.40 g BP-50-FT was added again and the mixture was stirred for 3 hours.

[0113] The mixture was concentrated on a rotary evaporator and the solvent mixture was completely removed. 150 g of the solvent-free polymer was dissolved in 150 g of n-butyl acetate.

[0114] GPC according to DIN 55672-1 :2016-03 (eluent: THF; standard: PMMA): Mw = 14 900 g / mol; Mn = 8610 g / mol; PDI = 1.7.

[0115] Copolymer E:

[0116] In a 500 mL four necked flask equipped with reflux condenser and N2 line, dropping funnel, KPG stirrer (200 rpm) and Pt 100 digital internal thermometer, initially 29.9 g of n-butyl acetate was charged and the oil bath was heated to 145 °C. A mixture of 9.8 g APO, 56.0 g i-BMA, 67.1 g MPEG500MA and 2.2 g 2-mercaptoethanol was added dropwise over 4 hours. In this case, the mixture was initially added dropwise for 1.5 hours with a drop speed of 1 drop per 4 seconds, then for another 2.5 hours with a drop speed of 1 drop per 2 seconds and the mixture was stirred for another 30 minutes at this temperature. The mixture was cooled to 80 °C and 0.14 g APO dissolved in 10 g of n-butyl acetate was dosed for the make-up reaction. Another 15 g of isobutyl acetate was added and the mixture was stirred for another 30 minutes without heating.

[0117] GPC according to DIN 55672-1 :2016-03 (eluent: THF; standard: PMMA): Mw = 8474 g / mol; Mn = 2426 g / mol; PDI = 3.5.

[0118] Copolymer F:

[0119] In a 550 mL four-necked flask, equipped with a reflux condenser and N2 line, dropping funnel, KPG stirrer (200 rpm) and Pt 100 digital internal thermometer, initially 29.9 g n-butyl acetate was charged and the oil bath was heated to 145 °C. A mixture of 9.8 g APO, 56.0 g i-BMA, 67.1 g MPEG500MA and 2.2 g 2-mercaptoethanol was continuously added dropwise over 4 hours at a rate of 1 drop per 2 seconds and stirred for another 30 minutes at this temperature. The mixture was cooled to 80 °C and 0.14 g APO dissolved in 10 g n-butyl acetate was dosed for the replenishment of the reaction. Another 15 g of isobutyl acetate was added and the mixture was stirred for another 30 minutes without heating.

[0120] GPC according to DIN 55672-1 :2016-03 (eluent: THF; standards: PMMA): Mw = 6181 g / mol; Mn = 2276 g / mol; PDI = 2.7.

[0121] Example 2: Rigid PUR foam

[0122] The following foam formulations were used for performance comparison:

[0123] Components Ratio by weight Polyether polyol* 100 Catalyst** 2 Surfactant*** 2 Water 1 Cyclopentane 14 MDI**** 193

[0124] * R 471 from Huntsman, OH value of 470 mg KOH / g

[0125] ** 8 from Evonik Operations GmbH

[0126] *** surfactant: **** copolymer as described in example 1 or Lutensol® XP 100 from Evonik Operations GmbH B 8491

[0127] **** polymeric MDI, 200 mPa*s, 31.5% NCO, functionality of 2.7.

[0128] The foaming was carried out by hand mixing. For this purpose, the polyol, catalyst, water, foam stabilizer and blowing agent were weighed into a beaker and mixed for 30 seconds by means of a disc stirrer (6 cm in diameter) at 1000 rpm. By reweighing, the amount of blowing agent that had evaporated in the mixing operation was determined and this amount of blowing agent was added again. Now the MDI was added, the reaction mixture was stirred with the stirrer for 7 seconds at 2500 rpm and immediately transferred into an open mold with dimensions of 27.5 x 14 x 14 cm (W x H x D).

[0129] After 10 minutes the foam was demolded. The foam was analyzed one day after foaming. The cell structure was evaluated subjectively on a scale from 1 to 10, wherein 10 stands for (idealized) flawless very fine foam and 1 for coarse foam with very obvious defects.

[0130] The results are summarized in the following table:

[0131] Surfactant Score TEGOSTAB B 8491 7.0 Copolymer A 6.5 Copolymer B 7.5 Copolymer C 1.5 Copolymer D Foam collapse Copolymer E 7.0 Copolymer F 7.0

[0132] The results show that the use of copolymers A, B and E and F is on the same level or slightly better than the use of siloxane based cell stabilizers especially in terms of cell structure and foam quality.

[0133] The influence of the copolymers according to the present application on all other application relevant foam properties is only negligible if at all.

[0134] Example 3: Rigid PIR foam

[0135] The following foam formulations were used for performance comparison:

[0136] Components Ratio by weight Polyester polyol* 100 Amine catalyst** 0.6 Potassium trimerisation catalyst*** 4 Surfactant**** 2 Water 1 Cyclopentane 16 MDI***** 199

[0137] * PS 2352 from Stepan, OH value of 250 mg KOH / g

[0138] ** 5 from Evonik Operations GmbH

[0139] *** 75 from Evonik Operations GmbH

[0140] **** surfactant: **** copolymer as described in example 1 or Lutensol® XP 5 from Evonik Operations GmbH B 8871

[0141] **** polymeric MDI, 200 mPa*s, 31.5% NCO, functionality of 2.7.

[0142] Comparative foaming was done by hand mixing. For this purpose, polyol, catalyst, water, foam stabilizer and blowing agent were weighed into a beaker and mixed by a disc stirrer (6 cm in diameter) at 1000 rpm for 30 seconds. By re-weighing, the amount of blowing agent evaporated in the mixing operation was determined and this amount of blowing agent was added again. Now MDI was added, the reaction mixture was stirred with the stirrer at 3000 rpm for 5 seconds and immediately transferred into an open mold with dimensions 27.5 x 14 x 14 cm (W x H x D).

[0143] After 10 minutes, the foam was demolded. The foam was analyzed one day after foaming. The cell structure was evaluated subjectively on a scale of 1 to 10, where 10 stands for (idealized) flawless very fine foam and 1 for coarse foam with very obvious defects.

[0144] The results are summarized in the following table:

[0145] Surfactant Score TEGOSTAB B 8871 8.0 Copolymer A 7.5 Copolymer B 8.0 Copolymer C 4.5 Copolymer D 2.0 Copolymer E 8.0 Copolymer F 7.5

[0146] The results show that the use of copolymers A, B and E and F is on the same level or slightly better than the use of siloxane-based cell stabilizers, especially in terms of cell structure and foam quality.

[0147] The influence of the copolymers according to the application on all other application-relevant foam properties, if any, is only marginal.

[0148] Example 4: Rigid PIR foam

[0149] The following foam formulations were used for performance comparison:

[0150] Components Ratio by weight Polyester polyol* 100 Amine catalyst** 0.4 Potassium trimerisation catalyst*** 5 Surfactant**** 2 Water 0.8 Cyclopentane / iso-pentane 70:30 19.5 TCPP 10 MDI***** 220

[0151] * PS 2412 from Stepan, OH value 240 mg KOH / g

[0152] ** 5 from Evonik Operations GmbH

[0153] *** 70 LO from Evonik Operations GmbH

[0154] **** surfactant: **** copolymer as described in example 1 or B 8871

[0155] **** polymeric MDI, 200 mPa*s, 31.5% NCO, functionality 2.7.

[0156] Comparative foaming was done by hand mixing. For this purpose, the polyol, catalyst, water, foam stabilizer, flame retardant and blowing agent were weighed into a beaker and mixed by a disc stirrer (6 cm in diameter) at 1000 rpm for 30 seconds. By re-weighing, the amount of blowing agent evaporated during the mixing operation was determined and the amount of blowing agent was added again. Now the MDI was added and the reaction mixture was stirred with the stirrer at 3000 rpm for 5 seconds and immediately transferred into a 25 cm x 50 cm x 7 cm aluminum mold lined with a polyethylene film and thermostated to 60°C.

[0157] After 10 minutes, the foam was demolded. The foam was analyzed one day after foaming. The surface and internal defects were evaluated subjectively on a scale of 1 to 10, where 10 represents an (idealized) flawless foam and 1 a foam with very obvious defects. The thermal conductivity coefficient (lambda value, in mW / m-K) was determined on 2.5 cm thick discs at an average temperature of 10°C using a HestoLambda Control type model HLC X206 device according to the provisions of standard EN 12667:2001.

[0158] The results are summarized in the following table:

[0159]

[0160] The results show that the use of copolymers A and B is at the same level or slightly better than the use of a siloxane-based cell stabilizer, especially in terms of foam quality and thermal conductivity.

[0161] The influence of the copolymers according to the application on all other application- related foam properties, if any, is only marginal.

[0162] Example 5: Rigid PIR foam

[0163] The following foam formulations were used for performance comparison:

[0164] Components Ratio by weight Polyester polyol* 100 Amine catalyst** 0.4 Potassium trimerisation catalyst*** 5 Surfactant**** 2 Water 0.8 Cyclopentane / iso-pentane 70:30 19.5 TCPP 10 MDI***** 199

[0165] Isoexter 4973 from COIM, OH value 210 mg KOH / g

[0166] ** 5 from Evonik Operations GmbH

[0167] *** 70 LO from Evonik Operations GmbH

[0168] ****Surfactant:**** Copolymer as described in Example 1 or Lutensol® XP 100 from Evonik Operations GmbH B 8871

[0169] ****Polymeric MDI, 200 mPa*s, 31.5% NCO, functionality of 2.7.

[0170] The comparative foaming was carried out by hand mixing. For this purpose, the polyol, catalyst, water, foam stabilizer, flame retardant and blowing agent were weighed into a beaker and mixed for 30 seconds by means of a disc stirrer (6 cm in diameter) at 1000 rpm. By reweighing, the amount of blowing agent evaporated in the mixing operation was determined and this amount of blowing agent was added again. Now the MDI was added, the reaction mixture was stirred with the stirrer at 3000 rpm for 5 seconds and immediately transferred into a 25 cm x 50 cm x 7 cm aluminum mold lined with a polyethylene film and thermostatted to 60°C.

[0171] After 10 minutes, the foam was demolded. The foam was analyzed one day after foaming. The surface and internal defects were evaluated subjectively on a scale of 1 to 10, where 10 stands for an (idealized) flawless foam and 1 for a foam with very obvious defects. The thermal conductivity coefficient (lambda value, in mW / m-K) was determined on 2.5 cm thick discs at an average temperature of 10°C using a device of the type Hesto Lambda Control, model HLC X206, according to the provisions of standard EN 12667:2001.

[0172] The results are summarized in the following table:

[0173]

[0174] The results show that the use of copolymers A and B is on the same level as the use of a siloxane-based cell stabilizer, especially in terms of foam quality and thermal conductivity.

[0175] The influence of the copolymers according to the application on all other application-relevant foam properties, if any, is only marginal.

Claims

1. A composition for producing rigid polyurethane foam, comprising at least one isocyanate component, a polyol component, and optionally a catalyst for the formation of urethane or isocyanurate bonds, characterized in that... The composition comprises, as a blowing agent, a hydrocarbon having 3, 4, or 5 carbon atoms; hydrofluorocarbon; hydrofluoroolefin (HFO); hydrohaloolefin; oxygen-containing blowing agent and / or hydrochloric hydrocarbon, and further comprises, as a foam stabilizer, an acrylate and / or methacrylate copolymer, wherein the acrylate and / or methacrylate copolymer is prepared without the use of benzoyl peroxide (BPO) as an initiator. The acrylate and / or methacrylate copolymer is based on at least one H2C=CR 1 -COOR 2 Type comonomer and at least one H2C=CR 1 -COOR 3 Type of comonomer, in which R 1 Each is independently -H or -CH3, with each having a distinct R. 1 Different substituents in a comonomer can coexist in a single molecule. R 2 Each is independently a group selected from saturated or unsaturated linear, cyclic, or branched aliphatic or aromatic hydrocarbons having 1 to 25 carbon atoms, wherein each has a distinct R group. 2 Different substituents in a comonomer can coexist in a single molecule. R 3 Each group is independently selected from polyethers based on structure 1, wherein each group has a distinct R group. 3 Different substituents in a comonomer can coexist in a single molecule. in x ranges from 3 to 500. R 4 Each is independently a hydrogen group or a group selected from saturated or unsaturated linear, cyclic, or branched aliphatic or aromatic hydrocarbons having 1 to 12 carbon atoms, wherein in group R 3 Different R 4 Substituents may exist in any order or sequence. R 5 It is -CH2-O-, -CH2-CH2-O-, -CH2-CH2-CH2-O-, -CH2-CH2-CH2-CH2-O- or -CH2-CH2-CH2-CH2-CH2-O-, where R 5 It can also be omitted at will. R 6 Each group is independently a hydrogen group, a group selected from saturated or unsaturated linear, cyclic or branched aliphatic or aromatic hydrocarbons having 1 to 25 carbon atoms, an acyl group, a group with the structure -CH2-CH(OH)-CH2OH, or a group with the structure -CH2-C(CH2OH)2-CH2-CH3, wherein each group has a distinct R group. 6 Different substituents in a comonomer can coexist in a single molecule. Of these, based on the total amount of foam stabilizer, Si-containing foam stabilizer is present at less than 5% by weight.

2. The composition according to claim 1, wherein R 2 Each can be independently methyl, ethyl, n-butyl, isobutyl, tert-butyl, 2-ethylhexyl, isodel, cyclohexyl, benzyl, phenyl, isoborneol, or allyl. x is greater than 5, R 4 Each can be independently -H, methyl, ethyl, or styryl. R 6 Each can be independently -H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, or tert-butyl.

3. The composition according to claim 1, wherein x is 8 to 100.

4. The composition according to any one of claims 1 or 2, characterized in that... The blowing agent used is a hydrocarbon having 3, 4 or 5 carbon atoms; hydrofluorocarbon; perfluorinated compound; hydrohaloolefin; water; oxygen-containing compound; and / or hydrochlorocarbon.

5. The composition according to claim 4, wherein the hydrohaloolefin is a hydrofluoroolefin.

6. The composition according to claim 4, characterized in that... The hydrocarbon having 3, 4, or 5 carbon atoms is cyclopentane, isopentane, and / or n-pentane; the hydrofluorocarbon is HFC 245fa, HFC 134a, and HFC 365mfc; the perfluorinated compound is perfluoropentane, perfluorohexane, and / or perfluorohexene; the hydrohalogenated olefin is 1234ze, 1234yf, 1224yd, 1233zd(E), and / or 1336mzz; the oxygen-containing compound is methyl formate, acetone, and / or dimethoxymethane; the hydrochlorocarbon is dichloromethane and / or 1,2-dichloroethane.

7. The composition according to claim 5, wherein the hydrofluoroolefin is 1234ze, 1234yf, 1224yd, 1233zd(E) and / or 1336mzz.

8. The composition according to any one of claims 1 to 3, characterized in that The acrylate and / or methacrylate copolymer has a number-average molecular weight Mn in the range of 500-100,000 g / mol, wherein the number-average molecular weight Mn is determined by gel permeation chromatography according to DIN 55672-1:2016-03 using THF as the eluent and PMMA as the standard.

9. The composition according to claim 8, characterized in that... The acrylate and / or methacrylate copolymer has a number-average molecular weight Mn in the range of 1000-20000 g / mol.

10. The composition according to claim 8, characterized in that... The acrylate and / or methacrylate copolymer has a number-average molecular weight Mn in the range of 1000-15000 g / mol.

11. The composition according to any one of claims 1 to 3, characterized in that, Based on 100 parts by weight of the polyol component, the total mass ratio of the acrylate and / or methacrylate copolymer is 0.1-10 pphp.

12. The composition according to claim 11, characterized in that, Based on 100 parts by weight of the polyol component, the total mass ratio of the acrylate and / or methacrylate copolymer is 0.5-5 pphp.

13. The composition according to claim 11, characterized in that, Based on 100 parts by weight of the polyol component, the total mass ratio of the acrylate and / or methacrylate copolymer is 1-4 pphp.

14. The composition according to any one of claims 1 to 3, characterized in that The composition does not contain tin-containing catalysts.

15. The composition according to any one of claims 1 to 3, characterized in that... The acrylate and / or methacrylate copolymers have been produced using TBPEH, i.e., tert-butyl peroxy-2-ethylhexanoate, and / or APO, i.e., tert-amyl peroxy-2-ethylhexanoate, as initiators.

16. The composition according to any one of claims 1 to 3, characterized in that The acrylate and / or methacrylate copolymer has a residual monomer content of less than 1%.

17. A method for producing rigid polyurethane foam by reacting one or more polyol components with one or more isocyanate components, characterized in that... The reaction is carried out using the composition according to any one of claims 1 to 16.

18. The rigid polyurethane foam obtainable by the method according to claim 17.

19. Use of the composition according to any one of claims 1 to 16 for providing a rigid polyurethane foam having improved insulation properties.

20. Use of the rigid polyurethane foam according to claim 18, as an insulating board and / or insulating material.

21. Use of the rigid polyurethane foam according to claim 20, for use in cooling equipment.

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