Production of rigid polyurethane or polyisocyanurate foams

Abstract

A composition for producing rigid polyurethane or polyisocyanurate foams is described, the composition comprising at least one isocyanate component, a polyol component, optionally a foam stabilizer, and optionally a blowing agent, the composition comprising at least one catalyst that catalyzes the formation of urethane or isocyanurate bonds, the catalyst comprising a zinc salt and / or a zinc-containing formulation.

Description

[Technical field]

[0001] The present invention relates to the field of polyurethane (PU) and polyisocyanurate (PIR), in particular rigid PU or PIR foams. The present invention particularly relates to the preparation of rigid PU or PIR foams using zinc salts, as well as the use of foams prepared therewith. In the present invention, the foams are rigid PU or PIR foams.

[0002] In the present invention, polyurethane (PU) is understood to mean in particular the products obtainable by reaction of polyisocyanates with polyols or compounds having isocyanate-reactive groups. In addition to polyurethanes, further functional groups may also be formed, such as uretdione, carbodiimide, isocyanurate, allophanate, biuret, urea and / or uretonimine. PU in the sense of the present invention is therefore understood to mean not only polyurethanes, but also polyisocyanurates, polyureas and polyisocyanate reaction products containing uretdione, carbodiimide, allophanate, biuret and uretonimine groups. In the present invention, polyurethane foams (PU foams) are understood to mean in particular the foams obtainable as reaction products based on polyisocyanates with polyols or compounds having isocyanate-reactive groups. In addition to the polyurethanes named here, further functional groups, such as, for example, allophanate, biuret, urea, carbodiimide, uretdione, isocyanurate or uretonimine, can also be formed.

[0003] The present invention is concerned in particular with the formation of polyisocyanurates. This reaction is formally called trimerization, since three isocyanate groups react to produce an isocyanurate ring. The production of rigid PIR foams is described in the literature and is usually carried out by reacting polyisocyanates with compounds that have hydrogen atoms reactive towards isocyanate groups, usually polyetherols, polyesterols or both, with an isocyanate index advantageously greater than or equal to 180. In addition to the urethane structures resulting from the reaction of isocyanates with compounds that have reactive hydrogen atoms, the reaction of isocyanate groups with each other results in isocyanurate structures, or further structures resulting from the reaction of isocyanate groups with other groups, for example polyurethane groups.

[0004] In the production of rigid polyurethane and polyisocyanurate foams, various catalysts are used to favorably influence the blowing reaction profile and the use properties of the foam. The formation of polyisocyanurates is advantageous since it leads to better mechanical properties (high compression hardness) and improved flame retardancy.

[0005] Various publications are known regarding the use of catalysts to promote the trimerization reaction in the production of rigid PU or PIR foams, thereby improving the compression hardness.

[0006] EP 1 878 493 A1 describes the use of carbocationic compounds as trimerization catalysts, the anions of which are based on dicarbonyl compounds. There is no mention of the use of zinc carboxylates.

[0007] US Patent 4,452,829 describes the production of spray foams using triols with molar masses of more than 1000 g / mol. Here, Zn salts are used in combination with K salts to accelerate creaming, i.e. the initiation of the PU reaction with water. To shorten the cream time, i.e. to accelerate the reaction, a Zn-containing catalyst (zinc octoate) is also added to the K-containing catalyst.

[0008] US Pat. No. 4,200,699 describes a gel catalyst composition for the production of rigid PU foams which contains Zn, K and Sb carboxylates, preferably with a further gel catalyst from the group of tertiary amines, inorganic tin compounds or organotin compounds.

[0009] EP 1 745 847 A1 describes a trimerization catalyst based on potassium octoate and a solvent which is inert with respect to reaction with isocyanates.

[0010] WO 2016 / 201675 describes trimerization catalysts that consist of compositions based on sterically hindered carboxylates having isocyanate-reactive groups and tertiary amines.

[0011] WO 2010 / 054317 describes iminium salts as trimerization catalysts.

[0012] WO 2013 / 074907 describes the use of tetraalkylguanidine salts of aromatic carboxylic acids as catalysts for polyurethane foams.

[0013] The object of the present invention was to make it possible to provide rigid polyurethane or polyisocyanurate foams which have particularly advantageous use properties, such as good compression and / or indentation hardness, even after particularly short reaction times, while advantageously minimizing the influence on the rise profile.

[0014] Surprisingly, it has now been found that this problem can be solved by the use of zinc salts and / or zinc-containing formulations.

[0015] The subject of the present invention is therefore a composition for producing rigid polyurethane or polyisocyanurate foams, the composition comprising at least one isocyanate component, a polyol component, optionally a foam stabilizer, and optionally a blowing agent, the composition comprising at least one catalyst that catalyzes the formation of urethane or isocyanurate bonds, the catalyst comprising a zinc salt and / or a zinc-containing formulation.

[0016] In the sense of the present invention, a zinc-containing formulation is a formulation that contains zinc. Furthermore, a formulation is a blend, mixture or solution of two or more substances. Thus, a zinc-containing formulation in the sense of the present invention is a formulation that contains zinc and at least one further component.

[0017] The zinc-containing formulation may include any desired additional components, but preferably includes a solvent and at least one nitrogen-containing compound.

[0018] The solvent and at least one nitrogen-containing compound are described in detail below. Thus, preferred zinc-containing formulations in the sense of the present invention comprise a zinc salt, a solvent, and at least one nitrogen-containing compound, in particular as each is defined below.

[0019] It has been found that the use of the compositions according to the invention in the production of rigid PU or PIR foams results in corresponding rigid foams that exhibit improved use properties. In particular, trimerization is improved, which results in a rapid hardening of the foam, i.e. the foam already has high compression hardness and high indentation hardness at an early stage. A further particular advantage of the invention is that the use of the compositions according to the invention nevertheless allows the rise profile to be minimally affected. This is highly advantageous, since otherwise problems with the flowability of the reaction mixture may arise, which would lead to significant processing problems. Using the compositions according to the invention, it is also possible in some cases to slow down the rise profile, which allows a wide variety of options for adjusting the reactivity of the foam system.

[0020] The effect of being able to slow down the PU reaction by adding zinc-containing compounds is surprising and novel: according to the prior art, zinc-containing compounds lead to an acceleration of the reaction, i.e. a shortening of the cream time or gel time, as described, for example, in US Pat. No. 442,829.

[0021] The solution according to the invention thus makes it possible to produce products based on rigid PU or PIR foams, such as insulation panels or cooling units, with a very particularly high quality and at the same time to set up the production process of rigid PU or PIR foams more efficiently.

[0022] A further advantage of the present invention is the good ecotoxicity classification of the chemicals that can be used, in particular the zinc salts or zinc-containing preparations, since the prior art often uses metal compounds with toxicologically questionable properties (Sn, Pb, etc.).

[0023] The present invention has the further advantage that it can be used to produce rigid PU or PIR foams with fewer foam defects.

[0024] According to a preferred embodiment of the invention, the zinc salts and / or zinc-containing formulations include zinc(II) salts, advantageously zinc(II) carboxylates, which are based on carboxylic acids having 1 to 34 carbon atoms, which may contain unsaturated or aromatic units, in particular zinc(II) acetate, zinc(II) propionate, zinc(II) pivalate, zinc(II) 2-ethylhexanoate (zinc(II) octanoate), zinc(II) isononanoate (zinc(II) 3,5,5-trimethylhexanoate), zinc(II) neodecanoate, zinc(II) ricinoleate, zinc(II) palmitate, ), zinc(II) stearate, zinc(II) oleate, zinc(II) laurate, zinc(II) naphthenate and / or zinc(II) benzoate, where most preferred are zinc(II) acetate and / or zinc(II) ricinoleate, and / or the carboxylates can also have N and O as heteroatoms, including in particular zinc(II) lactate, zinc(II) glycinate, zinc(II) hippurate and / or zinc(II) citrate and / or zinc(II) soaps, such as in particular zinc oleate, zinc palmitate and / or zinc stearate.

[0025] The composition according to the invention preferably contains zinc carboxylate in stoichiometric form, i.e. Zn and carboxylate in a molar ratio of 1:2, i.e. does not contain an excess of carboxylate or carboxylic acid in particular.In industrial processes for the preparation of zinc salts, the parent acid is often used in excess, so that the final product still contains an excess of acid.This is not advantageous here.

[0026] The total amount of zinc salt used is advantageously in the range of 0.025% to 2% by weight, preferably 0.05% to 1.6% by weight, particularly preferably 0.1% to 1.2% by weight, based on the total composition.

[0027] Within the meaning of the present invention, it is very particularly preferred to introduce the zinc salts and / or zinc-containing preparations for use in the PU or PIR reaction mixture in dissolved form.

[0028] Thus, according to one preferred embodiment of the invention, the zinc salt and / or zinc-containing formulation according to the invention in a carrier medium is added to the reaction mixture, or the zinc-containing formulation advantageously comprises the carrier medium. The terms carrier medium and solvent are used synonymously within the meaning of the present invention.

[0029] In particular, preferred zinc-containing formulations comprise zinc salts, advantageously zinc(II) salts, in particular zinc(II) carboxylates, in a carrier medium, which in particular includes glycols, alkoxylates and / or oils of synthetic and / or natural origin, which corresponds to one preferred embodiment of the present invention.

[0030] In principle, all substances suitable as solvents can be used as carrier medium.Preferably, for example, glycols, alkoxylates and / or oils of synthetic and / or natural origin can be mentioned.It is also possible to use protic solvents or aprotic solvents.

[0031] The zinc-containing formulations according to the invention can also be used as components of compositions having various carrier media.

[0032] In order to provide zinc-containing formulations that are easy to use, the use of a carrier medium is preferred. In this case, it is preferable for the viscosity to be as low as possible so that the formulation does not impose specific demands on pumps and other industrial equipment. The preferred viscosity is less than 10 Pa·s, preferably less than 8 Pa·s, particularly preferably less than 6 Pa·s, measured at 25°C by the Hoeppler method described in DIN 53655.

[0033] In addition, it is very particularly preferred in the sense of the present invention if the composition according to the invention further comprises at least one nitrogen-containing compound, which can optimally promote the solubility of the zinc salt in the various carrier media. It is possible here to use preferably amines, amine alkoxylates, amino acids and / or amines with multiple acid functions, in particular N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine, 2-[[2-[2-(dimethylamino)ethoxy]ethyl]methylamino]ethanol, fatty amine ethoxylates, such as tallowamine ethoxylate, cocoamine ethoxylate, cetyl / stearylamine ethoxylate, PEG-3-tallowaminopropylamine, PPG-3-tallowaminopropylamine, glycine, lysine, arginine, sarcosine, ethylenediaminetetraacetate and / or ethylenediaminetriacetate cocosalkylacetamide, particularly preferably fatty amine alkoxylates, where at least one nitrogen-containing compound is present, in particular in a zinc-containing formulation. Most preferred are N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine and / or N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine.

[0034] These additionally usable nitrogen-containing compounds are advantageously contained in an amount of 0.01% to 3% by weight, preferably 0.02% to 2% by weight, particularly preferably 0.1% to 1.5% by weight, based on the total composition according to the invention.

[0035] Thus, very particularly preferred zinc-containing formulations include: (a) zinc salts (preferably zinc(II) salts, in particular zinc(II) carboxylates), in particular those mentioned above; (b) a carrier medium, which may include, among others, glycols, alkoxylates, or synthetic and / or naturally occurring oils; (c) Nitrogen-containing compounds, in particular those mentioned above, with very particular preference given as nitrogen-containing compounds to N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine and / or N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine.

[0036] Furthermore, if the composition according to the invention further comprises at least one additional trimerization catalyst, this corresponds to a preferred embodiment of the invention, which does not itself comprise zinc but is additionally added according to a preferred embodiment of the invention.

[0037] The additional trimerization catalyst can be used to adjust the reaction rate to the desired extent if desired. The additional trimerization catalyst can also be a constituent of the zinc-containing formulation, which corresponds to a preferred embodiment. In another preferred embodiment, the additional trimerization catalyst is not a constituent of the zinc-containing formulation, but is provided separately to the composition according to the invention.

[0038] In principle, it is possible to use all known trimerization catalysts. Particularly suitable additional trimerization catalysts are, for example, carboxylates of ammonium cations, such as tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, dimethyldiallylammonium, trimethyl(2-hydroxypropyl)ammonium, triethyl(2-hydroxypropyl)ammonium, tripropyl(2-hydroxypropyl)ammonium, tributyl(2-hydroxypropyl)ammonium, trimethyl(2-hydroxyethyl)ammonium, triethyl(2-hydroxyethyl)ammonium, tripropyl(2-hydroxyethyl)ammonium, tributyl(2-hydroxyethyl)ammonium, dimethylbenzyl(2-hydroxyethyl)ammonium, dimethylbenzyl(2-hydroxypropyl)ammonium carboxylates, etc. Also suitable as cations are potassium or other alkali metals or alkaline earth metals, in particular as described in EP 1 745 847 A1 and WO 2016 / 201675 A1 and the references contained therein. Advantageously, potassium carboxylates are used, in particular potassium acetate, potassium formate, potassium propionate, potassium butanoate, potassium pentanoate, potassium hexanoate, potassium heptanoate, potassium 2-ethylhexanoate, potassium pivalate, potassium octanoate, potassium butyrate, potassium isobutyrate, potassium nonanoate, potassium decanoate, potassium ricinoleate, potassium stearate and / or potassium neodecanoate.

[0039] A preferred composition according to the invention comprises an additional trimerization catalyst in an amount ranging from 0.2% to 9% by weight, advantageously from 0.5% to 7% by weight, relative to the total composition according to the invention.

[0040] Thus, preferred compositions according to the invention comprise a zinc salt (advantageously a zinc(II) salt, in particular a zinc(II) carboxylate), a carrier medium, a nitrogen-containing compound and optionally, but advantageously as an essential component, an additional trimerization catalyst, whereby the additional trimerization catalyst which can be optionally, but advantageously as an essential component, is preferably not a constituent of the zinc-containing formulation.

[0041] Furthermore, if the composition according to the present invention does not contain Sb carboxylate and / or Sn carboxylate, this corresponds to one preferred embodiment of the present invention.

[0042] If the composition according to the invention further comprises a tertiary amine as further catalyst (i.e. an additional tertiary amine), which advantageously comprises at least two nitrogen atoms per molecule, this represents a further preferred embodiment of the invention.

[0043] Particularly preferred additional tertiary amines that can be used are selected from the first group, which includes the following amines: pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl)ether, tris(dimethylaminopropyl)amine, N-[2-[2-(dimethylamino)ethoxy]ethyl]-N-methyl-1,3-propanediamine, 2-{[2-(dimethylamino)ethyl]methylamino}ethanol, 2-[[2-[2-(dimethylamino)ethoxy]ethyl]methylamino]ethanol, N-methyl-N-(N,N-dimethylaminopropyl)aminopropanol, N-methyl-N-(N,N-dimethylaminopropyl)aminoethanol, 1-bis[3-(dimethylamino)propyl]amino]-2-propanol, 1,1'[[3-(dimethylamino)propyl]amino]-2-propanol, 3,3'-iminobis(N,N-dimethylpropylamine), diisopropyltrimethyldiethylenetriamine, ... The amines which may be used include 1-(dimethylaminopropyl)methylamine, bis(dimethylaminopropyl)methylamine, trimethylaminoethylethanolamine, 3-dimethylamino-N,N-dimethylpropionamide, dimethylaminopropylamine, 1-(3-aminopropyl)pyrrolidine, 1-(2-aminoethyl)pyrrolidine, 1-(1-pyrrolidinyl)-2-propanamine, N,N-dimethyl-1-(pyrrolidin-1-yl)propan-2-amine, tris(dimethylaminopropyl)amine, N,N,N'N'-tetramethylethylenediamine, 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine, N,N'-bis[3-(dimethylamino)propyl]urea, N-[3-(dimethylamino)propyl]urea, 1,3-bis(dimethylamino)propane, and N,N,N'N'-tetramethylhexamethylenediamine, and mixtures of the aforementioned amines may also be used. This means, for example, that it is advantageously possible to use any single amine of the aforementioned first group or to use a mixture of amines of the aforementioned first group, which corresponds to one preferred embodiment of the present invention.

[0044] Additional tertiary amines that can be advantageously used further include those of the structural formula (III): [ka] [In the formula, m is 1 or 2; A is O, S or NR e and R a , R b , R c , R d and R e is an alkyl or functionalized alkyl having 1 to 20 carbon atoms. The use of a tertiary amine of structural formula (III) represents a preferred embodiment of the present invention.

[0045] Further additional tertiary amines which can be advantageously used are represented by the following structural formulas IV, V or VI: [ka] [In the formula, m is 1 or 2; R f is H, methyl, ethyl, isopropyl, 3-hydroxypropyl, 2-hydroxypropyl, hydroxyethyl, 3-aminopropyl, 2-aminopropyl or aminoethyl, where these two groups can be different or identical. The use of amines of formula IV, V or VI corresponds to a preferred embodiment of the present invention. It is also possible here to use corresponding amine mixtures.

[0046] The tertiary amines which can additionally be used, advantageously those mentioned above, in particular those selected from the first group and / or according to formula III, IV, V or VI, have the function of acting as catalysts, whereas the nitrogen-containing compounds mentioned above, in particular N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine and / or N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine, serve to further increase the solubility of the zinc salt.

[0047] Very particularly preferred compositions according to the invention comprise, which may additionally be used, advantageously a tertiary amine selected from the above-mentioned, preferably the first group and / or according to formula III, IV, V or VI, in an amount of 0.05% to 3% by weight, advantageously 0.1% to 2% by weight, relative to the overall composition according to the invention.

[0048] Thus, very particularly preferred compositions according to the invention comprise a zinc salt (advantageously a zinc(II) salt, in particular a zinc(II) carboxylate), a carrier medium, a nitrogen-containing compound, optionally, advantageously as essential components, an additional trimerization catalyst and an additional tertiary amine, advantageously a tertiary amine selected from the above-mentioned, preferably the first group and / or according to formula III, IV, V or VI, where it is preferred that the additional tertiary amine is not a constituent of the zinc-containing formulation.

[0049] Thus, very particularly preferred compositions according to the invention comprise (i) A zinc-containing formulation comprising a zinc(II) salt, in particular a zinc(II) carboxylate, a carrier medium and a nitrogen-containing compound, preferably as described above. As a further component, the preferred composition further comprises an additional trimerization catalyst, advantageously as described above, and Additional tertiary amines, advantageously selected from the above-mentioned, preferably the first group, and / or according to formula III, IV, V or VI. Includes.

[0050] According to a further preferred embodiment of the invention, the composition according to the invention further comprises a salt of an amino acid and / or an amino acid derivative.

[0051] These salts of amino acids or amino acid derivatives can be derived formally from the reaction of aromatic carboxylic acids with amino acids, and they can also be obtained in particular by the reaction of amino acids with aromatic carboxylic acids, aromatic carboxylic esters, aromatic carboxylic acid halides and / or aromatic carboxylic acid anhydrides, which corresponds to a preferred embodiment of the present invention, where the conversion to salts can be carried out by conventional methods, for example by reaction with conventional bases, such as KOH, NaOH or the corresponding ammonium hydroxides.

[0052] Particularly preferred salts of amino acids or amino acid derivatives according to the invention have the following formula (I): [ka] [In the formula, R 3 is an aromatic group, optionally a polycyclic aromatic group, which may bear substituents and optionally a further carboxy function to which a further amino acid may be attached; Here, R 3 Advantageously, [ka] and R 1 , R 2 , R 4 are, independently of each other, H, C1 to C 18 alkyl, alkenyl, aryl or alkylaryl, which may be substituted; M + is a cation, for example advantageously an alkali metal cation or an ammonium cation or a substituted ammonium cation, preferably Li + , Na + , K + , Rb + , Cs +or ammonium compounds, such as, advantageously, tetraalkylammonium, trialkylhydroxyalkylammonium, benzyltrialkylammonium, tetramethylammonium, tetraethylammonium, tetrabutylammonium, tetrapropylammonium, dimethyldiallylammonium, trimethyl(2-hydroxypropyl)ammonium, triethyl(2-hydroxypropyl)ammonium, tripropyl(2-hydroxypropyl)ammonium, tributyl(2-hydroxypropyl)ammonium, dimethylbenzyl(2-hydroxypropyl)ammonium or dimethylbenzyl(2-hydroxyethyl)ammonium and combinations thereof.

[0053] Particularly preferred here is R 3 represents phenyl, alkylphenyl, or a group derived from phthalic acid, isophthalic acid, terephthalic acid, or pyromellitic acid.

[0054] The salt of the amino acid derivative is represented by the following formula (II): [ka] [In the formula, R 1 , R 2 , M + is as defined above, where advantageously R 2 are each H, where more preferably R 1 and R 2 are H, respectively, where, in particular, R 1 and R 2 are H and M + is Na + , K + or NR 1 4 + represents R 1 A particularly preferred embodiment exists when the following is satisfied:

[0055] Thus, a particularly preferred structure is [ka] and [ka] [In the formula, M + and R 1 is as defined above.

[0056] Particularly preferred are salts of hippuric acid. [ka] [In the formula, M + is as defined above, advantageously with sodium, potassium or ammonium as cation, particularly preferred are the sodium salts [ka] It is.

[0057] The preparation of the salts which can be used according to the invention can be carried out by known methods.

[0058] Hippuric acid and its salts are commercially available. The preparation is known to those skilled in the art. The preparation of hippuric acid can be carried out, for example, by reaction of benzoyl chloride with glycine (Schotten Baumann method). Amidation based on benzoic acid ester (methyl ester) with glycine can also be carried out. In that case, the preparation of salts is carried out, for example, with the corresponding base, such as KOH, NaOH or the corresponding ammonium hydroxide.

[0059] A preferred composition according to the invention may additionally contain salts of amino acids and / or amino acid derivatives which may be used in an amount of 2% to 50% by weight, advantageously 4% to 45% by weight, based on the total composition according to the invention.

[0060] A further major advantage of the present invention is that technical grade quality is often sufficient for use in PU or PIR foams as any secondary components from the manufacturing process do not affect the foam production.

[0061] According to a preferred embodiment of the present invention, the salts of amino acids and / or amino acid derivatives in a carrier medium can be added to the reaction mixture. As the carrier medium, all substances suitable as solvents can be used, such as glycols, alkoxylates or synthetic and / or natural oils. The use of a carrier medium for the salts of amino acid derivatives corresponds to a preferred embodiment of the present invention. It is also possible to use the salts according to the present invention as components of compositions with various carrier media.

[0062] If the total weight proportion of the zinc-containing preparation according to the invention relative to the finished polyurethane foam is between 0.01% and 10% by weight, preferably between 0.1% and 5% by weight, this corresponds to a preferred embodiment of the invention.

[0063] If the composition according to the invention comprises water and / or a blowing agent, optionally at least one flame retardant and / or further additives which can be advantageously used in the production of rigid polyurethane or polyisocyanurate foams, this corresponds to a preferred embodiment of the invention. In addition to the zinc-containing formulation according to the invention, further catalysts may also be included.

[0064] Particularly preferred compositions according to the invention comprise the following components: a) at least one isocyanate-reactive component, in particular a polyol; b) at least one polyisocyanate and / or polyisocyanate prepolymer; c) the catalyst according to the invention as described above (in particular the zinc-containing formulation according to the invention), d) (optionally) a further catalyst; e) (optionally) a foam stabilizing component based on siloxane or other surfactant; f) one or more blowing agents; g) Further additives, fillers, flame retardants etc.

[0065] A preferred zinc-containing formulation that can be used in the present invention is (i) a zinc(II) carboxylate, advantageously as defined above, in an amount between 2% and 50% by weight, advantageously between 5% and 45% by weight and particularly preferably between 10% and 40% by weight, (ii) a carrier medium, advantageously as defined above, in an amount of 10% to 95% by weight, advantageously 15% to 90% by weight, particularly preferably 20% to 70% by weight, (iii) nitrogen-containing compounds, advantageously as defined above, in an amount of 1% to 70% by weight, advantageously 2% to 60% by weight, particularly preferably 5% to 30% by weight; wherein each weight percentage is based on the total zinc-containing formulation.

[0066] Particularly preferred zinc-containing formulations that can be used in the present invention are (i) a zinc(II) carboxylate, advantageously as defined above, in an amount between 2% and 50% by weight, advantageously between 5% and 45% by weight and particularly preferably between 10% and 40% by weight, (ii) a carrier medium, advantageously as defined above, in an amount of 10% to 95% by weight, advantageously 15% to 90% by weight, particularly preferably 20% to 70% by weight, (iii) nitrogen-containing compounds, advantageously as defined above, in an amount of 1% to 70% by weight, advantageously 2% to 60% by weight, particularly preferably 5% to 30% by weight, (iv) an additional trimerization catalyst as defined above in an amount of 5% to 75% by weight, advantageously 10% to 70% by weight, particularly preferably 15% to 60% by weight; wherein each weight percentage is based on the total zinc-containing formulation.

[0067] Very particularly preferred compositions according to the invention comprise the zinc-containing formulation just defined and furthermore an additional tertiary amine, advantageously selected from the first group and / or according to formula III, IV, V or VI as defined above.

[0068] A further subject of the present invention is a process for the preparation of rigid polyurethane or polyisocyanurate foams by reaction of one or more polyol components with one or more isocyanate components, the reaction being carried out in the presence of a catalyst which catalyzes the formation of urethane or isocyanurate bonds, preferably using the compositions according to the invention as described above, the catalyst being zinc salts and / or zinc-containing formulations, including in particular those mentioned above, where in addition to the zinc-containing formulations according to the invention which can be preferably used, it is also possible to use further catalysts.

[0069] It is now preferred to provide the zinc-containing formulation to the reaction mixture for producing rigid PU or PIR foams in a carrier medium, which advantageously comprises glycols, alkoxylates or oils of synthetic and / or natural origin.

[0070] A further subject of the present invention is the use of zinc salts and / or zinc-containing formulations as catalysts in the production of rigid polyurethane or polyisocyanurate foams, preferably for improving the use properties of rigid polyurethane or polyisocyanurate foams, in particular for increasing the compression hardness, measurable in accordance with DIN EN ISO 844:2014-11, of rigid polyurethane or polyisocyanurate foams at an earlier time point than rigid polyurethane or polyisocyanurate foams produced without the use of zinc salts and / or zinc-containing formulations, in particular with the use of the compositions according to the invention as described above.

[0071] A further subject of the present invention are rigid polyurethane or polyisocyanurate foams obtainable by the process according to the invention as described above.

[0072] The subject of the invention is furthermore the use of the rigid polyurethane or polyisocyanurate foams according to the invention for thermal insulation purposes, preferably as insulation boards and fittings, as well as in cooling equipment which comprises the rigid polyurethane or polyisocyanurate foams according to the invention as insulation.

[0073] Below, the individual possible components (herein designated a) to g) are described in more detail. Component c) has already been described.

[0074] Polyols suitable as polyol component a) in the sense 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 the polyether polyols and / or polyester polyols and / or hydroxyl group-containing aliphatic polycarbonates, in particular polyether polycarbonate polyols and / or polyols of natural origin, the so-called "natural oil-based polyols" (NOPs), which are customarily used for the production of polyurethane systems, in particular polyurethane coatings, polyurethane elastomers or even foams. The polyols usually have a functionality of 1.8 to 8 and a number-average molecular weight in the range of 500 to 15 000. Usually, polyols with a hydroxyl number in the range of 10 to 1200 mg KOH / g are used.

[0075] Polyether polyols can be used. 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 alkoxides or amines as catalysts, preferably with the addition of at least one starter molecule containing two or three reactive hydrogen atoms in bond form, or by cationic polymerization of alkylene oxides in the presence of Lewis acids, for example antimony pentachloride or boron trifluoride ether compounds, or by double metal cyanide catalysis. Suitable alkylene oxides contain 2 to 4 carbon atoms in the alkylene group. Examples include tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, advantageously ethylene oxide and 1,2-propylene oxide are used. The alkylene oxides can be used individually, cumulatively, in blocks, alternatingly or as mixtures.

[0076] As starter molecules, in particular compounds having at least two, preferably 2 to 8, hydroxyl groups or compounds having at least two primary amino groups in the molecule are used. As starter molecules, for example, water, dihydric, trihydric or tetrahydric alcohols, such as ethylene glycol, propane-1,2- and -1,3-diol, diethylene glycol, dipropylene glycol, glycerin, 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 with formaldehyde, and Mannich condensation products of phenol with formaldehyde and dialkanolamines, and melamine, or amines, such as aniline, EDA, TDA, MDA and PMDA, particularly preferably TDA and PMDA, can be used. The choice of suitable starter molecules depends on the respective field of application of the resulting polyether polyol in polyurethane production.

[0077] Polyester polyols can be used. The polyester polyols are based on esters of polyvalent 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, decanedicarboxylic 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 condensation of these polyvalent carboxylic acids with polyhydric alcohols, preferably diols or triols having 2 to 12, particularly preferably 2 to 6, carbon atoms, preferably trimethylolpropane and glycerin.

[0078] Polyether carbonate polyols can be used. Polyether carbonate polyols are polyols that contain carbon dioxide in the bound state as carbonate. The use of carbon dioxide as a comonomer in alkylene oxide polymerization is particularly important from a commercial point of view, since carbon dioxide is produced in large quantities as a by-product in many processes in the chemical industry. Replacing part of the alkylene oxide in the polyol with carbon dioxide can clearly reduce the cost of producing the polyol. Furthermore, the use of CO2 as a comonomer is also very advantageous from an environmental point of view, since this is a reaction that converts greenhouse gases into polymers. The production of polyether polycarbonate polyols by the addition of alkylene oxides and carbon dioxide to H-functional starter substances using catalysts has been known for many years. In this case, various catalyst systems can be used. The first generation are heterogeneous zinc or aluminum salts, as described, for example, in US Pat. No. 3,900,424 or US Pat. No. 3,953,383. Furthermore, mononuclear and binuclear metal complexes have been successfully used for the copolymerization of CO2 with 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 with alkylene oxides are the complex metal cyanide catalysts, also called DMC catalysts (US Pat. No. 4,500,704, WO 2008 / 058913). Suitable alkylene oxides and H-functional starter substances are those that are also used for the preparation of carbonate-free polyether polyols, as mentioned above.

[0079] Polyols based on renewable raw materials, "natural oil-based polyols" (NOPs), can be used. NOPs for polyurethane foam production are gaining importance in view of the long-term limited availability of fossil resources, i.e. oil, coal and gas, and against the background of high crude oil prices, and have already been described many 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 currently commercially available from various manufacturers (WO 2004 / 020497, US 2006 / 0229375, WO 2009 / 058367). Depending on the base raw material (for example soybean oil, palm oil or castor oil) and the subsequent processing, polyols with different property profiles are obtained. Here, a distinction can be made between two groups: a) polyols based on renewable raw materials, which have been improved so that they can be used 100% in the production of polyurethanes (WO 2004 / 020497, US 2006 / 0229375); b) polyols based on renewable raw materials, which, due to processing and properties, can only replace petrochemical-based polyols to a certain extent (WO 2009 / 058367).

[0080] A further class of polyols that can be used are the so-called filled polyols (polymer polyols). These polyols are characterized by the presence of a solid organic filler in a dispersed distribution, with a solid content of 40% or more. In particular, SAN polyols, PUD polyols and PIPA polyols can be used. SAN polyols are highly reactive polyols that contain dispersed copolymers based on styrene / acrylonitrile (SAN). PUD polyols are highly reactive polyols that also contain dispersed polyurea. PIPA polyols are highly reactive polyols that contain dispersed polyurethanes, formed, for example, by in situ reaction of isocyanates with alkanolamines in conventional polyols.

[0081] Preferably, polyols with a molar mass of less than 1000 g / mol are used. Even more preferred are polyols with a functionality of less than 3. In particular, it is preferred not to use triols with a molar mass of more than 1000 g / mol. This respectively corresponds to a particularly preferred embodiment of the invention.

[0082] A preferred ratio of isocyanate to polyol is expressed as a blending index, i.e., 100 times the stoichiometric ratio of isocyanate groups to isocyanate-reactive groups (e.g., OH groups, NH groups), and is preferably within the range of 10 to 1000, preferably 40 to 700, particularly preferably 60 to 600, and particularly preferably 150 to 550. A more preferred range is 250 to 500, and even more preferably 300 to 450.

[0083] An index of 100 represents a 1:1 molar ratio of reactive groups.

[0084] According to the invention, PIR formulations based on at least 70%, 80% or 90% polyester in the polyol component are preferred.

[0085] In one particularly preferred embodiment, polyester polyols based on aromatic carboxylic acids are used in an amount of more than 50 pphp, preferably more than 70 pphp, per 100 parts by weight of the polyol component.

[0086] Preferred aromatic polyester polyols have a hydroxyl number in the range from 150 to 400 mg KOH / g, preferably from 170 to 350 and very particularly preferably from 180 to 300 mg KOH / g.

[0087] As isocyanate component b), preferably one or more organic polyisocyanates having two or more isocyanate functional groups are used. As polyol component, preferably one or more polyols having two or more isocyanate-reactive groups are used.

[0088] Isocyanates suitable as isocyanate components within the meaning of the present invention are all isocyanates having at least two isocyanate groups. In general, it is possible to use all aliphatic, cycloaliphatic, arylaliphatic and advantageously aromatic polyfunctional isocyanates known per se. Particularly preferably, isocyanates are used in the range of 60 to 200 mol %, based on the total of the isocyanate consuming components.

[0089] Examples which may be mentioned here are alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene group, such as 1,12-dodecane diisocyanate, 2-ethyltetramethylene-1,4-diisocyanate, 2-methylpentamethylene-1,5-diisocyanate, 1,4-tetramethylene diisocyanate and preferably 1,6-hexamethylene diisocyanate (HMDI), cycloaliphatic diisocyanates, such as 1,3- and 1,4-cyclohexane diisocyanate and any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane diisocyanate, San (isophorone diisocyanate or abbreviated IPDI), 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 diisocyanate (MDI) with polyphenylpolymethylene polyisocyanate (crude MDI), and mixtures of crude MDI with toluene diisocyanate (TDI). The organic diisocyanates and polyisocyanates can be used individually or in the form of their mixtures. It is also possible to use the corresponding "oligomers" of diisocyanates (IPDI trimers, biurets, uretdiones based on isocyanurates). Furthermore, it is also possible to use prepolymers based on the abovementioned isocyanates.

[0090] It is also possible to use isocyanates modified by introducing a urethane group, a uretdione group, an isocyanurate group, an allophanate group, or the like, that is, so-called modified isocyanates.

[0091] Particularly suitable and therefore particularly advantageously used organic polyisocyanates are the various isomers of toluene diisocyanate (2,4- and 2,6-toluene diisocyanate (TDI) in pure form or as compositionally different isomer mixtures), 4,4'-diphenylmethane diisocyanate (MDI), the so-called "crude MDI" or "polymeric MDI" (which contains, in addition to the 4,4' isomer of MDI, the 2,4' and 2,2' isomers and polynuclear products), and binuclear products, designated "pure MDI", which consist mainly of mixtures of the 2,4' and 4,4' isomers or prepolymers thereof. Examples of particularly suitable isocyanates are detailed, for example, in EP 1 712 578, EP 1 161 474, WO 00 / 58383, U.S. Patent Application Publication No. 2007 / 0072951, EP 1 678 232 and WO 2005 / 085310, which are hereby incorporated by reference in their entirety.

[0092] In addition to the catalyst according to the invention, i.e. the zinc salts and / or zinc-containing preparations mentioned above, any catalyst d) can be used.

[0093] Suitable additional optional catalysts d) in the sense of the present invention are all compounds capable of promoting the reaction of isocyanates with OH, NH or other isocyanate-reactive groups, as well as with each other. Here, 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), ammonium compounds, organometallic compounds and metal salts, preferably salts of potassium, tin, iron, bismuth. In particular, mixtures of several components can be used as catalysts.

[0094] As component e) it is also possible to use Si-free surfactants or organomodified siloxanes.

[0095] The use of such substances in rigid foams is known. It is now possible to use in the present invention all compounds which aid in the production of foams (stabilization, cell regulation, cell opening, etc.). These compounds are well known from the prior art.

[0096] Corresponding siloxanes that can be used in the context of the present invention are described, for example, in the following patents: CN 103665385, CN 103657518, CN 103055759, CN 103044687, US 2008 / 0125503, US 2015 / 0057384, EP 1520870, EP 1211279, EP 0867464, EP 0867465, EP 0275563. The cited documents are incorporated herein by reference and are considered to be part of the disclosure of the present invention. The use of polyether-modified siloxanes is particularly preferred.

[0097] The use of blowing agents f) is optional, depending on which foaming method is used. It is possible to work with chemical and physical blowing agents. The choice of blowing agent here strongly depends on the nature of the system.

[0098] In one particularly preferred embodiment, no HFO is used as the blowing agent.

[0099] Depending on the amount of blowing agent used, high or low density foams can be produced. For example, 5 kg / m 3 ~900kg / m 3 It is possible to produce foams having a density of 8 to 800, particularly preferably 10 to 600 kg / m 3 , especially 30-150kg / m 3 It is.

[0100] As physical blowing agents, corresponding compounds with suitable boiling points can be used. It is also possible to use chemical blowing agents that react with NCO groups to release gas, such as water or formic acid. Examples of blowing agents are liquefied CO2, nitrogen, air, easily volatile liquids, such as hydrocarbons with 3, 4 or 5 carbon atoms, preferably cyclopentane, isopentane and n-pentane, hydrofluorocarbons, preferably HFC245fa, HFC134a or HFC365mfc, chlorofluorocarbons, preferably HCFC141b, hydrofluoroolefins (HFOs) or hydrohaloolefins, such as 1234ze, 1234yf, 1233zd(E) or 1336mzz, oxygen-containing compounds, such as methyl formate, acetone and dimethoxymethane, or chlorinated hydrocarbons, preferably dichloromethane and 1,2-dichloroethane.

[0101] The suitable water content in the sense of the present invention depends on whether one or more blowing agents are used in addition to water: for purely water-foamable foams, the value is preferably 1-20 pphp, and if other blowing agents are additionally used, the amount of water used is preferably reduced to 0.1-5 pphp.

[0102] As additives g) it is possible to use all substances known from the prior art which are used in the production of polyurethanes, in particular polyurethane foams, such as crosslinkers and chain extenders, stabilizers against oxidative degradation (so-called antioxidants), flame retardants, surfactants, biocides, cell-improving additives, cell-opening agents, solid fillers, antistatic additives, nucleating agents, thickeners, dyes, pigments, color pastes, fragrances, emulsifiers, etc.

[0103] The process for producing rigid PU or PIR foams according to the invention can be carried out by known methods, for example by hand mixing or preferably by using a foaming machine. When carrying out the process by using a foaming machine, it is possible to use a high-pressure or low-pressure machine. The process according to the invention can be carried out either batchwise or continuously.

[0104] Preferred rigid polyurethane or polyisocyanurate foam formulations in the sense of the present invention have a foam density of 5 to 900 kg / m 3 and advantageously has the composition shown in Table 1.

[0105] [Table 1]

[0106] For further preferred embodiments and configurations of the inventive method, reference is furthermore made to the details already given above in relation to the composition according to the invention.

[0107] As already mentioned, a further subject of the present invention are rigid PU or PIR foams obtainable by the process described above.

[0108] Rigid PU or PIR foam is an established technical term. The known fundamental difference between flexible and rigid foams is that flexible foams exhibit elastic behavior and therefore deformation is reversible. In contrast, rigid foams are permanently deformed. In the present invention, rigid PU or PIR foam is understood to mean in particular foams according to DIN 7726:1982-05, which have a compressive strength according to DIN 53 421 / DIN EN ISO 604:2003-12 of advantageously ≧20 kPa, advantageously ≧80 kPa, preferably ≧100 kPa, more preferably ≧150 kPa, particularly preferably ≧180 kPa. In addition, according to DIN EN ISO 4590:2016-12, rigid PU or PIR foam advantageously has a closed cell content of more than 50%, advantageously more than 80%, particularly preferably more than 90%.

[0109] According to one preferred embodiment of the invention, the polyurethane foam has a viscosity of advantageously between 5 and 900 kg / m 3 , preferably 8 to 800, particularly preferably 10 to 600 kg / m 3 , especially 30-150kg / m 3The foam has a density of 0.01g / g.

[0110] In particular, it is possible to produce a predominantly closed-cell foam, the closed-cell content being advantageously >80%, advantageously >90%.

[0111] The rigid PU or PIR foams according to the invention can be used as or in the production of insulation materials, advantageously insulation boards, refrigerators, insulation foams, roof liners, packaging foams or spray foams.

[0112] The PU or PIR foams according to the invention can in particular be advantageously used in the refrigeration industry, the refrigeration appliance industry and the household appliance industry, for example for the production of insulating boards for roofs and walls, as insulation in containers and warehouses for frozen goods and in refrigeration and freezing appliances.

[0113] Further preferred areas of use are vehicle construction, in particular vehicle inner roof liners, car body parts, interior trim, cooling vehicles, large containers, transport pallets, the manufacture of packaging laminates, the furniture industry, e.g. furniture parts, doors, linings, electronics applications.

[0114] The cooling equipment according to the invention has as insulation a PU or PIR foam (polyurethane or polyisocyanurate foam) according to the invention.

[0115] A further subject of the present invention is the use of rigid PU or PIR foams as insulation materials, as insulation boards, as spray foams, as one-component foams in low temperature technology, in cooling units, in the construction sector, in the automotive sector, in the shipbuilding sector and / or in the electronics sector.

[0116] The subject matter according to the invention is described above and exemplarily below, without the invention being limited to these exemplary embodiments. When ranges, general formulae or classes of compounds are given, these include not only the corresponding ranges or compounds explicitly mentioned, but also all subranges and subcompounds that can be obtained by selecting individual values ​​(ranges) or compounds. When documents are cited in this specification, their entire contents, especially those that form the context in which they are cited, are incorporated into the disclosure of the present invention. Unless otherwise stated, percentage data are weight percentage data. When average values ​​are given, these are weight average values, unless otherwise stated. When parameters determined by measurement are given, the measurements were carried out at a temperature of 25° C. and a pressure of 101,325 Pa, unless otherwise stated.

[0117] The following examples are provided to illustratively explain the present invention, and are not intended to limit the scope of the present invention, the scope of which is clear from the entire specification and the claims, to the embodiments described in the examples.

[0118] Working Example The following ingredients were used to prepare the foam: Stepanpol® PS 2352: Polyester polyol from Stepan Daltolac® R 471: Huntsman polyether polyol TCPP: Tris(2-chloroisopropyl)phosphate manufactured by ICL KOSMOS® 75, potassium octanoate catalyst from Evonik Operations GmbH KOSMOS® 45 MEG, potassium octanoate catalyst from Evonik Operations GmbH POLYCAT® 5, amine catalyst from Evonik Operations GmbH POLYCAT® DP, amine catalyst from Evonik Operations GmbH POLYCAT® 9, amine catalyst from Evonik Operations GmbH POLYCAT® 206, amine catalyst from Evonik Operations GmbH POLYCAT® 77, amine catalyst from Evonik Operations GmbH TEGOAMIN® BDE, amine catalyst from Evonik Operations GmbH DABCO® T, an amine catalyst from Evonik Operations GmbH DABCO® NE 300, amine catalyst from Evonik Operations GmbH DABCO® TMR 31, final cure catalyst from Evonik Operations GmbH MDI (44V20): Desmodur® 44V20L, diphenylmethane 4,4'-diisocyanate (MDI) from Covestro, as well as isomers and higher functional homologues Tegostab® B 8460, foam stabilizing surfactant from Evonik Operations GmbH

[0119] Preparation of the zinc-containing formulation according to the invention: Each component may be prepared and then combined in a foaming operation to obtain a composition according to the invention (or not).

[0120] The corresponding components / compositions can be added in premixed form or as individual components to the reaction mixture to be foamed. The examples containing zinc are according to the invention.

[0121] Component A: Zinc acetate 12.5 g of zinc acetate dihydrate (available from Sigma-Aldrich) was dissolved in monoethylene glycol along with 15 g of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, resulting in a zinc acetate content of 11%.

[0122] Component B: Zinc propionate 12 g of zinc propionate (available from Sigma-Aldrich) was dissolved in monoethylene glycol along with 15 g of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, resulting in a zinc propionate content of 12%. Component C: Zinc ricinoleate based: Kosmos® 54, Evonik Operations GmbH.

[0123] Further Zn-free components used in the examples: D component: Sodium hippurate (available from Sigma-Aldrich) was dissolved in monoethylene glycol to give a sodium hippurate content of 25%.

[0124] Component E: Potassium acetate system: Kosmos® 45 MEG from Evonik Operations GmbH.

[0125] Component F: Potassium Propionate: Potassium propionate (available from Sigma-Aldrich) was dissolved in monoethylene glycol such that the potassium propionate content was 30%.

[0126] Component G: Potassium octanoate type: Kosmos® 75 from Evonik Operations GmbH.

[0127] Component H: Potassium pivalate system: DABCO® TMR 20 from Evonik Operations GmbH.

[0128] Component I: DABCO® TMR 31 from Evonik Operations GmbH.

[0129] Working Example: PU foam manufacturing: Foaming was carried out by hand mixing. For this purpose, the compound according to the invention, the polyol, the flame retardant, the catalyst according to the invention or not, the water, the siloxane surfactant and the blowing agent were weighed into a beaker and mixed with a disk stirrer (diameter 6 cm) at 1000 rpm for 30 seconds. The amount of blowing agent evaporated during the mixing process was determined by reweighing and replenished. The isocyanate (MDI) was then added and the reaction mixture was stirred with the described stirrer at 3000 rpm for 5 seconds.

[0130] To obtain a free-rising foam, the reaction mixture was introduced into a suitable beaker with a diameter of 20 cm at the upper edge. The amount of reaction mixture was selected so that the tip of the dome-shaped foam at the edge was 10-15 cm high above the upper edge of the beaker.

[0131] During foaming, the gel time was measured to evaluate the effect of the catalyst on the foaming rate. After 3 minutes, the dome-shaped foam was cut at the top edge of the beaker to obtain a round foam surface. The indentation hardness of the foam was measured at this surface.

[0132] Method for measuring indentation hardness: For this purpose, the force with which an indenter with a diameter of 4 cm was pressed into the foam was measured. The indentation force was measured at an indentation depth of 5 mm. The measurements were carried out after 4, 6, 8 and 10 minutes, with the indenter being pressed into the cut surface at four different points arranged in a circle.

[0133] How to measure compression hardness: The compressive strength of the foam is measured on cubic test specimens with a side length of 5 cm up to a compression degree of 10% in accordance with DIN EN ISO 844:2014-11 (the maximum compressive stress occurring in this measurement range is reported).

[0134] Table 2 summarizes the foam formulations used (Formulation 1 to Formulation 9). [Table 2-1] [Table 2-2]

[0135] Foaming results using the trimerization catalyst of the present invention Table 3: Summary of foam testing using various catalysts and foam formulations according to the invention

[0136] Reported are the components used (Cmp.AI, according to the invention or not according to the invention depending on the composition), their amounts fed (Dos.pphp), the formulations of Table 2 used, the gel time (GT) (sec) and the indentation hardness (Newton) after the time indicated in minutes (after mixing with MDI). The Zn-free catalyst composition is not according to the invention. [Table 3-1] [Table 3-2]

[0137] The foams according to the invention show a significantly higher indentation hardness than the respective comparative examples.

[0138] It is clear from this that the trimerization catalysts according to the invention allow for improved foam cure in various formulations, in some cases even extending the gel time and even further improving the positive effect on full cure at comparable gel times.

[0139] This is a significant advantage since the minimal effect on gel time accelerates the cure of the foam while maintaining the processability of the reaction mixture, e.g., with respect to the flowability of the foaming mixture.

[0140] It is evident from the experiments that the trimerization catalyst according to the invention leads to an improved hardening of the foam. The very good results mentioned above for the indentation hardness of the foam according to the invention are similarly observed for the compression hardness.

Claims

1. 1. A composition for producing rigid polyurethane or polyisocyanurate foams, the composition comprising at least one isocyanate component and a polyol component, the composition comprising at least one catalyst that catalyzes the formation of urethane or isocyanurate bonds, the composition comprising a zinc salt and / or a zinc-containing formulation.

2. 2. The composition of claim 1, wherein the zinc salt and / or zinc-containing formulation comprises a zinc(II) salt.

3. 3. The composition according to claim 2, wherein the zinc(II) carboxylate used is present in stoichiometric form, i.e. comprises Zn and carboxylate in a molar ratio of 1:

2.

4. 3. The composition of claim 1 or 2, wherein the zinc-containing formulation comprises a zinc salt in a carrier medium.

5. 3. The composition of claim 1 or 2, further comprising at least one nitrogen-containing compound, wherein said at least one nitrogen-containing compound is included in said zinc-containing formulation.

6. 3. The composition of claim 1 or 2, further comprising at least one additional trimerization catalyst.

7. 3. The composition of claim 1 or 2, further comprising a salt of an amino acid and / or an amino acid derivative, said salt being formally derivable from the reaction of an aromatic carboxylic acid with an amino acid.

8. 3. The composition of claim 1 or 2, further comprising a tertiary amine as an additional catalyst.

9. 3. The composition according to claim 1, wherein the total weight percentage of the zinc-containing formulation relative to the finished polyurethane foam is between 0.01% and 10% by weight.

10. The composition comprises a zinc-containing formulation, the zinc-containing formulation comprising: (i) a zinc(II) carboxylate in an amount of 2% to 50% by weight, (ii) a carrier medium, in an amount of from 10% to 95% by weight; (iii) a nitrogen-containing compound in an amount of 1% to 70% by weight 3. The composition of claim 1 or 2, wherein the weight percentages are based on the total zinc-containing formulation.

11. The composition, a zinc-containing formulation comprising a zinc(II) salt, a carrier medium, and a nitrogen-containing compound, the composition further comprising, as a further component, (i) an additional trimerization catalyst, and (ii) an additional tertiary amine The composition of any one of claims 1 to 3, comprising:

12. The composition of claim 1 or 2, wherein the composition further comprises water and / or a blowing agent.

13. 1. A method for producing rigid polyurethane or polyisocyanurate foams by the reaction of one or more polyol components with one or more isocyanate components, said reaction being carried out in the presence of a catalyst that catalyzes the formation of urethane or isocyanurate linkages, characterized in that the catalyst comprises a zinc salt and / or a zinc-containing formulation.

14. 1. Use of zinc salts and / or zinc-containing formulations as catalysts in the production of rigid polyurethane or polyisocyanurate foams.

15. 14. Rigid polyurethane or polyisocyanurate foam obtainable by the process according to claim 13.

16. 16. Use of the rigid polyurethane or polyisocyanurate foams according to claim 15 for thermal insulation purposes, preferably as insulation boards and fittings, and in cooling equipment.