Composition for thermolatent catalysis in the production of at least one polyurethane

Abstract

The present invention relates to a composition for thermolatent catalysis in the production of at least one polyurethane, to a method for producing at least one polyurethane in the presence of the composition according to the invention, to a polyurethane, preferably a polyurethane foam, more particularly a polyurethane froth foam, obtained in the presence of the composition according to the invention, and to use of at least one polyurethane froth foam produced according to the invention for producing an article.

Description

[0001] COMPOSITION FOR THERMOLATENT CATALYSIS IN THE PRODUCTION OF AT LEAST ONE POLYURETHANE

[0002] The present invention relates to a composition for thermolatent catalysis in the production of at least one polyurethane, to a method for producing at least one polyurethane in the presence of the composition according to the invention, to a polyurethane, preferably a polyurethane foam, more particularly a polyurethane froth foam, obtained in the presence of the composition according to the invention, and to use of at least one polyurethane froth foam produced according to the invention for producing an article.

[0003] BACKGROUND OF THE INVENTION

[0004] Polyurethanes are produced by reaction of di- or higher-functional polyols with di- or higher-functional isocyanates. In processes relevant to applications, this so-called polyurethane reaction usually takes place with the addition of catalysts which accelerate the reaction. For many processes, it is important here that the catalysts have thermolatent properties. This means that they have no or only low catalytic activity at room temperature and are activated only at higher temperatures. This is important in all processes in which the polyol-isocyanate mixture is to be processable at room temperature for as long as possible and cures only when subsequently heated. Ideally, the complete thermal curing of the system then takes place within a few minutes. A corresponding reaction profile is in the production, for example, of mechanically foamed PU systems. Such foams are produced typically by mechanical foaming of a polyol-isocyanate mixture, in which air or nitrogen are forced into the polyol-isocyanate mixture with high shear input. The foam material thus produced can then be coated onto any desired substrate, for example the back of a carpet or else a release paper, and cured at elevated temperatures. To ensure that the polyol-isocyanate does not react during the foaming or coating operation itself, but instead does so only after coating onto a substrate, thermolatent reaction characteristics, as described above, are of particular importance in the production of such foams. On account of their production, mechanically foamed polyurethane foams are also referred to in specialist circles as froth foams. The term "froth foam" is also used for the present invention in exactly that manner.

[0005] In the past, a number of thermolatent catalysts have already been developed. A prominent example here are metal complexes based on acetylacetone, e.g. nickel(ll) acetylacetonate. Corresponding acety- lacetonates exhibit virtually no catalytic activity at room temperature, but allow the system to cure right through rapidly at temperatures > 70°C. However, a disadvantage of this class of substances is that acetylacetone is highly toxic and the corresponding metal acetylacetonates are also often themselves toxic and / or carcinogenic. Consequently, there has been a longstanding effort in the industry to find a replacement for this hitherto widespread class of catalyst.

[0006] An alternative to metal acetylacetonates are acid-blocked amine catalysts. Corresponding catalysts form thermoreversible acid-base pairs, which dissociate at elevated temperatures and thus release the catalytically active amine. However, a problem with this class of substances is that their activation temperature usually extends over a fairly wide range. Their thermolatent properties are therefore often less pronounced. For example, acid-blocked amines usually on the one hand exhibit too high a background reactivity at room temperature, if they still exhibit good through-curing at higher temperatures. If, on the other hand, they are so strongly blocked that the background reactivity is suppressed to a minimum at room temperature, they usually no longer have sufficient catalytic effect at elevated temperatures.

[0007] OBJECT OF THE INVENTION

[0008] The object of the present invention was therefore that of overcoming the disadvantages of the prior art. In particular, the object of the present invention was to provide innovative catalysts which have a pronounced thermolatent reactivity profile without having the disadvantages listed in the prior art.

[0009] SUMMARY OF THE INVENTION

[0010] The objects underlying the present invention are achieved by the composition of the invention for thermolatent catalysis in the production of at least one polyurethane, comprising

[0011] I) at least one metal compound; and

[0012] II) at least one polyether comprising at least one carboxyl group, wherein the at least one polyether comprising at least one carboxyl group is obtained by i) the reaction of at least one polyetheramine comprising at least one primary amino group with at least one hydroxy-functional lactone or at least one hydroxy-functional cyclic carbonate; and ii) reaction of the at least one reaction product from method step i) with at least one cyclic carboxylic anhydride.

[0013] The composition according to the invention has the advantage that it enables a pronounced thermolatent reaction profile in the production of a polyurethane. Thus the composition according to the invention is almost catalytically inactive at room temperature, which enables effective processing of the reaction mixture on which the polyurethane is based. At elevated temperatures, the compositions according to the invention allow rapid and complete through-curing of the polyurethane, which has an advantageous effect both on the process regime in the production of the polyurethane and on its end properties.

[0014] In addition, the composition according to the invention has the advantage that it is toxicologically harmless, which has an advantageous effect on its handling.

[0015] DESCRIPTION OF THE INVENTION

[0016] Percentages in the description and in the claims are percentages by weight (abbreviated as wt.%), unless otherwise specified. Concentrations in the description and in the claims refer to the total mass or the total volume of the solutions or dispersions or compositions concerned, unless otherwise specified. The terms preparation” and “composition” are for the purposes of the present invention to be understood as synonymous.

[0017] The various details and embodiments described hereinbelow can be combined with one another where this is technically possible and nothing to the contrary is specified.

[0018] The term “aliphatic” encompasses for the purposes of the present invention cyclic and acyclic (non-cy- clic), saturated and unsaturated carbon compounds, aromatic compounds being expressly not included under this term (cf. Compendium of Technical Terminology, Gold Book, International Union of Pure and Applied Chemistry, 2014, version 2.3.3, p. 57).

[0019] The term “alkyl” encompasses for the purposes of the present invention branched and unbranched alkyl groups including cyclic and / or acyclic structural elements, where cyclic structural elements comprise by definition at least three carbon atoms. C1-CX alkyl in the description and in the claims refers to alkyl groups comprising 1 to X carbon atoms (X is a natural number). For example, C1-C8 alkyl includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tertpentyl, neopentyl, hexyl, heptyl and octyl.

[0020] Where more than one radical needs to be selected for a compound named in the claims or in the description, said radicals are unless otherwise specified selected independently of one another, irrespective of whether selection is from one or more than one list. They may, if the lists provide for this, therefore be the same or different.

[0021] Where the term “at least one” is stated in the description and in the claims, this means that one or more than one, for example two or three, of the named elements may be selected. The same applies to higher numbers such as two or three.

[0022] Where parameters that have been determined by measurement are given hereinbelow, the measurements were carried out at a temperature of 25°C and a pressure of 101 325 Pa, unless otherwise stated.

[0023] Where chemical (empirical) formulae are used in the present invention, the stated indices may represent either absolute numbers or average values. In the case of polymeric compounds, the indices preferably represent average values. Structural and empirical formulae presented in the present invention are representative of all isomers that are possible by differing arrangement of the repeating units.

[0024] The composition of the invention comprises (or consists of):

[0025] I) at least one metal compound; and

[0026] II) at least one polyether comprising at least one carboxyl group. The at least one metal compound is preferably selected from the group consisting of tin compounds, zinc compounds, bismuth compounds, iron compounds, copper compounds, nickel compounds, zirconium compounds, aluminium compounds, titanium compounds and mixtures of the aforesaid, with bismuth, zinc and iron compounds being preferred in particular. The at least one metal compound is preferably a metal salt.

[0027] The metal compounds can contain the respective metal atoms in different oxidation states. Iron(lll) compounds are preferred as iron compounds. Bismuth(lll) compounds are preferred as bismuth compounds. Zinc(ll) compounds are preferred as zinc compounds.

[0028] The at least one metal compound is preferably in the form of oxide, hydroxide, oxide-hydroxide, sulfate, halide, carbonate or carboxylate. The at least one metal compound is particularly preferably present in the form of carboxylate. Very particularly preferably, the at least one metal compound is present in the form of neodecanoate, i.e. as the salt of neodecanoic acid.

[0029] The composition of the invention contains the at least one metal compound preferably in an amount of 0.5 to 60 wt.%, more preferably of 1 to 50 wt.%, even more preferably of 2 to 40 wt.%, based on the total mass of the composition.

[0030] The composition according to the invention contains at least one polyether comprising at least one carboxyl group.

[0031] The at least one polyetheramine preferably corresponds to the formula (1): where

[0032] R is a hydrocarbon radical having 1 to 4 carbon atoms, preferably a methyl radical;

[0033] Y and Z are selected from the group consisting of hydrogen and methyl radical, with the condition that one of Y and Z is hydrogen and the other is a methyl radical; m is an integer from the interval from 0 to 100; n is an integer from the interval from 0 to 100; with the proviso that the sum total of m and n is 5 to 200.

[0034] The unit ; prefer- ably it is a unit of the formula The integer m is preferably selected from the interval from 3 to 60, more preferably in the interval 5 to 40. The integer n is preferably selected from the interval from 5 to 80, more preferably in the interval 10 to 50. The sum total of m and n is preferably in the interval from 10 to 100, more preferably in the interval 15 to 50. In one embodiment of the present invention, m is preferably selected from the interval from 3 to 60, more preferably in the interval 5 to 40, n is preferably selected from the interval from 5 to 80, more preferably in the interval 10 to 50, and the sum total of m and n is preferably in the interval from 10 to 100, more preferably in the interval 15 to 50.

[0035] The at least one polyetheramine preferentially has a mass-weighted average molar weight (Mw) in the range from 400 g / mol to 5000 g / mol, preferably in the range from 500 g / mol to 3000 g / mol, more preferably in the range from 1000 g / mol to 2500 g / mol.

[0036] The at least one polyetheramine preferentially has a polydispersity (Mw / Mn) in the range from 1 .01 to 3, preferably in the range from 1 .02 to 2, more preferably in the range from 1 .03 to 1 .5.

[0037] Particularly preferably, the at least one polyetheramine has a weight-average molar mass of 1900 to 2100 g / mol, R a methyl radical, n is in the interval from 30 to 35 mol and m is in the interval 8 to 12 mol. Such polyetheramines are available as Jeffamine M-2070 from Huntsman.

[0038] Reaction with a hydroxy-functional lactone

[0039] According to the invention, any desired hydroxy-functional lactone can be used. Preferably, the at least one hydroxy-functional lactone is of a polyhydroxycarboxylic acid, more preferably the at least one hydroxyfunctional lactone is of a sugar acid, in particular the at least one hydroxyfunctional lactone is of a C5-C6 sugar acid, and very preferably is glucono-1 ,5-lactone.

[0040] In the reaction of the at least one polyetheramine with the at least one hydroxy-functional lactone, ring opening of the lactone and the formation of an amide function occur. The reaction of the at least one polyetheramine with the at least one hydroxy-functional lactone preferably takes place in the temperature range from 50°C to 200°C, more preferably from 80°C to 150°C. Preferably, the reaction of the at least one polyetheramine with the at least one hydroxy-functional lactone is carried out under inert conditions. For this purpose, for example, the reaction vessel can be inerted with a non-reactive gas, such as argon or nitrogen, prior to the reaction.

[0041] Preferably, the at least one polyetheramine is used equimolarly relative to the at least one hydroxy-functional lactone. In this case, a polyether polyol with 5 hydroxyl groups is formed.

[0042] Reaction with a hydroxy-functional cyclic carbonate

[0043] The at least one hydroxy-functional cyclic carbonate is preferably glycerol 1 ,2-carbonate. It is preferred that the at least one cyclic carboxylic anhydride is selected from the group consisting of maleic anhydride, succinic anhydride and phthalic anhydride.

[0044] Preferably, the at least one polyether comprising at least one carboxyl group has on average 1 .0 to 5.0 carboxyl groups (per molecule of the polyether), preferably 1 .3 to 4.0 carboxyl groups, particularly preferably 1 .5 to 3.5 carboxyl groups, more particularly 1 .7 to 2.5 carboxyl groups.

[0045] Preferably, the at least one polyether comprising at least one carboxyl group corresponds to the formula (2): where R, Y, Z, m and n have the meanings defined above and are subject to the conditions defined therein; and

[0046] X is selected from the building blocks of the formulae (3a), (3b) and (3c): where each B is independently selected from the group consisting of hydrogen atom and the building blocks ac- cording to one of the formulae (4a), (4b) and (4c): It is preferred if the molar ratio between the at least one metal compound and the at least one polyether comprising at least one carboxyl group in the composition according to the invention is in the ratio of 1 :0.05 to 1 :10, preferably in the range of 1 :0.1 to 1 :5, more preferably in the range of 1 :0.2 - 1 :3.

[0047] In addition to the at least one metal compound and the at least one polyether comprising at least one carboxyl group, the composition according to the invention may also contain further components, such as a carrier component, for example. The carrier component here can be used as a solvent or diluent in the composition according to the invention. Preferred carrier components here are selected from the group encompassing polyols (as defined below), glycols, such as ethylene glycol, propylene glycol, ethylene diglycol, propylene diglycol, butyl diglycol, polyethylene glycol or polypropylene glycol, carbonates, such as propylene carbonate, organic esters, such as isopropyl myristate or methyl esters of dicarboxylic acids (so-called dibasic esters), for example.

[0048] Another subject of the present invention is a method for producing at least one polyurethane, comprising the reaction of at least one isocyanate and at least one polyol in the presence of the composition according to the invention.

[0049] The term “polyurethane” in the context of this invention refers to materials which are formed by reacting polyisocyanates with compounds reactive towards them, preferably having OH groups (“polyols") and / or NH2groups (Adam et al., “Polyurethanes”, Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley VCH-Verlag, Weinheim - Chapters 1-3).

[0050] Compounds reactive towards the polyisocyanates are polyols in particular. Polyols are preferably selected from the group consisting of polyester polyol, polyether polyol, polyether polyols and polycarbonate polyol and mixtures of the aforesaid. Preferably, the polyol contains 2 to 6, preferably 2 to 4, (NCO-reac- tive) OH functions.

[0051] Suitable polyether polyols are known to those skilled in the art. They are preferably produced by addition reactions of alkylene oxides, such as ethylene oxide or propylene oxide, to a starter having at least two active hydrogen atoms. Examples of such starters are polyhydric alcohols (for example ethylene glycol, propylene glycol, glycerol, trimethylolpropane or pentaerythritol), aliphatic amines (for example ethylenediamine), aromatic amines (for example toluenediamine) and alkanolamines (for example ethanolamine and diethanolamine) and sugars (for example sorbitol, glucose and sucrose). The addition reaction can take place according to a method in “Polyurethane Handbook” (1985) by Gunter Oertel, Hanser Verlag Germany, pp. 42 to 53.

[0052] Suitable polyester polyols are likewise known to those skilled in the art. They are preferably prepared by reacting at least one dibasic acid with at least one polyhydric alcohol. The at least one dibasic acid is preferably selected from the group consisting of adipic acid, maleic acid, phthalic acid and terephthalic acid. As the polyhydric alcohol, preference is given to using glycols preferably selected from the group consisting of ethylene glycol, propanediol, butanediol, hexanediol, neopentyl glycol and cyclohexane-1 ,4- dimethanol.

[0053] Suitable polymer polyols are likewise known to those skilled in the art. They are preferably accessible by reacting the polyether polyols described above with ethy lenically unsaturated monomers, for example butadiene, acrylonitrile or styrene, in the presence of a radical initiator.

[0054] Suitable polycarbonate polyols are likewise known to those skilled in the art. They are preferably prepared by reacting a polyhydric alcohol (usually a glycol, preferably selected from the group consisting of ethylene glycol, propanediol, butanediol, hexanediol, neopentyl glycol and cyclohexane-1 ,4-dimethanol) with at least one carbonic ester (preferably dimethyl carbonate or diphenyl carbonate) and then removing the excess carbonic ester and the liberated monoalcohols to expose the terminal OH groups. Alternatively, polycarbonate polyols are obtainable by directly reacting diols with carbon dioxide in the presence of a suitable catalyst.

[0055] Suitable polyether polyols preferably have a mass-weighted average molar weight (Mw) of 750 to 6000 g / mol. The mass-weighted average molar weight (Mw) here can be preferably determined by means of gel permeation chromatography (GPC) using a column combination SDV 1000 / 10 000 A (length: 65 cm), at a temperature of 30°C, with THF as mobile phase and a flow rate of 1 ml / min, a sample concentration of 10 g / l, and an Rl detector calibrated against polypropylene glycol as standard.

[0056] Suitable polyester polyols preferably have a mass-weighted average molar weight (Mw) of 100 to 2500 g / mol, it being possible to determine the molar weight by means of GPC as described above.

[0057] Preferably, the polyols have an OH number in the range from 20 to 1000 mg KOH / g. Polyether polyols used with preference have an OH number in the range from 20 to 800 mg KOH / g. Polyester polyols used with preference have an OH number in the range from 40 to 1000 mg KOH / g. Suitable methods for determining the hydroxyl number are in particular those according to DGF C-V 17a (53) and Ph. Eur. 2.5.3 Method A.

[0058] Suitable isocyanates have at least 2 NCO groups (“isocyanate groups”) and are selected from the group of aliphatic, cycloaliphatic, araliphatic and aromatic isocyanates and polyurethane prepolymers. Preferred aromatic isocyanates are selected from the group comprising toluene 2,4-diisocyanate, diphenylmethane 4,4'-diisocyanate (4,4'-MDI), diphenylmethane 2,4'-diisocyanate (2,4'-MDI), diphenylmethane 2,2'-diisocy- anate (2,2'-MDI), urethane-modified liquid diphenylmethane 4,4'-diisocyanate, urethane-modified liquid diphenylmethane 2,4'-diisocyanate, urethane-modified liquid diphenylmethane 2,2'-diisocyanate, higher polycyclic homologues of diphenylmethane diisocyanate (also termed oligomeric, polymeric or technical MDI), naphthylene 1 ,2-diisocyanate, naphthylene 1 ,5-diisocyanate and mixtures of these substances, particular preference being given to MDI and / or polymeric MDI.

[0059] Suitable aliphatic or cycloaliphatic isocyanates are selected from the group containing tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methylpentamethylene 1 ,5-diisocyanate, 2-ethy Ibuty I- ene 1 ,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1 ,3-bis(isocyanatomethyl)cyclohexane (HXDI), cyclohexane 1 ,4-diisocyanate, 1 -methylcyclo- hexane 2,4-diisocyanate, 1 -methylcyclohexane 2,6-diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, dicyclohexylmethane 2,4'-diisocyanate, dicyclohexylmethane 2,2'-diisocyanate and mixtures of the aforesaid.

[0060] Suitable polyurethane prepolymers are likewise known to those skilled in the art. They are obtainable preferably by reacting at least one isocyanate with a substoichiometric amount of at least one polyol. The reaction is preferably carried out at a temperature of 30 to 100°C. The corresponding polyurethane prepolymers have at least two reactive NCO groups.

[0061] Within the scope of the present invention, the ratio of isocyanate to polyol, expressed as the NCO index, is preferably in the range from 40 to 500, more preferably 60 to 350, especially preferably 80-120. The NCO index here describes the ratio of isocyanate actually used to calculated isocyanate (for a stoichiometric reaction with polyol). An NCO index of 100 represents a molar ratio of reactive groups of 1 :1 .

[0062] In addition to the polyether-siloxane block copolymers according to the invention, the polyurethanes may also comprise further additives and adjuvants, such as, for example, fillers, blowing agents, co-catalysts, organic and inorganic pigments, foam stabilizers, hydrolysis stabilizers or UV stabilizers, antioxidants, absorbers, crosslinkers, dyes, emulsifiers or dispersing additives, levelling assistants or thickeners / rheology additives.

[0063] Preferred co-catalysts within the scope of the present invention are selected from the group of the gel catalysts that catalyse the polyurethane reaction between isocyanate and polyol. These may be selected from the class of amine catalysts, for example triethylamine, dimethylcyclohexylamine, tetramethylethylenediamine, tetramethylhexanediamine, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, triethylenediamine, dimethylpiperazine, 1 ,2-dimethylimidazole, N-ethylmorpholine, tris(dimethyla- minopropyl)hexahydro-1 ,3,5-triazine, dimethylaminoethanol, dimethylaminoethoxyethanol, tetramethylguanidine, and 1 ,8-diazabicyclo[5.4.0]undec-7-ene. In addition, amine catalysts may be selected from the class of what are known as emission-free catalysts, which are characterized in that they have a catalytically active nitrogen atom and an NCO-reactive group, for example an OH group. Corresponding emission-free amine catalysts are marketed for example under the Dabco NE product series from Evonik. In addition, the catalysts may be selected from the class of metal catalysts, for example tin-, zinc-, bismuth-, iron-, copper- or zirconium-based catalysts. Metal catalysts may here be used in the form of salts, for example, or as organically modified catalysts, for example tin laurate, tin octanoate, tin neodecanoate or bismuth neodecanoate.

[0064] Preferred foam stabilizers are selected within the scope of the present invention from the group of the polyether siloxanes. In particular, those polyether siloxanes which are selected from the group of [AB]nblock copolymers are preferred here. Such [AB]nblock copolymers usually have a linear structure and are composed of alternating polyether and siloxane chains. Polyether and siloxane chains can be linked to each other here via either a silicon-carbon linkage (Si-C) or a silicon-oxygen-carbon linkage (Si-O-C). Furthermore, preferred foam stabilizers may be selected from the group of pendant polyether siloxanes. Pendant polyethersiloxanes have a silicone chain which carries pendant and / or terminal polyether chains. The polyether chains can also be bonded to the silicone chain via an Si-C or an Si-O-C linkage.

[0065] Preferably, the composition according to the invention is used, in the production of at least one polyurethane, in a concentration in the range of 0.005 - 1 wt.%, preferably in the range of 0.01 - 0.5 wt.%, based on the total amount of the at least one polyurethane.

[0066] In the invention, it is preferred if the composition according to the invention is provided as a separate component and then added to the reaction mixture of at least one isocyanate and at least one polyol. However, it is also possible for the at least one metal compound, as described above, and the at least one polyether containing at least one carboxyl group, also as described above, to be added as separate components to the polyurethane system or a subcomponent of the polyurethane system, such as the polyol component. The reaction mixture or the corresponding subcomponent of the system is then regarded as the carrier medium of the catalytically active preparation.

[0067] Preferably, the polyurethanes produced by the method according to the invention are polyurethane foams, more particularly preferably polyurethane froth foams. Preferred polyurethane froth foams of the invention here contain at most up to 2 wt.%, more preferably up to 1 wt.%, especially preferably up to 0.5 wt.%, very preferably up to 0.1 wt.% of a chemical or physical blowing agent. The polyurethane froth foams especially preferably contain no physical or chemical blowing agent at all.

[0068] A further subject of the present invention is a process for producing polyurethane froth foams in the presence of the composition of the invention, comprising the process steps of a) providing at least one polyol component, at least one isocyanate component, a composition according to the invention and optionally further additives; b) mixing all the components to form a homogeneous mixture; c) mechanically foaming the mixture while introducing a gas, for example air or nitrogen, to give a foam; d) applying the foamed reaction mixture to a substrate, e) curing the foamed reaction mixture; to afford the polyurethane froth foam.

[0069] It is made clear that the process steps of this process as set out above are not subject to any fixed sequence in time. For instance, process steps b) and c) can be carried out simultaneously, meaning that individual components are added to and mixed with the reaction mixture only during the foaming procedure. Individual additives may also be added only after process step c) to the mechanically foamed reaction mixture.

[0070] In process step c), the mixture of polyol, isocyanate, composition of the invention and optionally further additives is foamed up, whereby a foamed reaction mixture is obtained. It is a preferred embodiment of the present invention for the mixture to be foamed by the application of high shearing forces. This may be effected with the aid of shear units familiar to those skilled in the art, for example Dispermats, dissolvers, Hansa mixers or Oakes mixers.

[0071] It is preferred within the present invention if the mixture is foamed in process step c) to a density in the range of 50-1000 g / l, preferably in the range of 75-600 g / l, more preferably in the range of 100-500 g / l.

[0072] In process step d), the foamed reaction mixture is applied to a substrate - examples of appropriate substrates are carpet backs, the back of artificial turf, adhesive coatings, textile carriers, release papers or release films - and also to metals, either to be left on the substrate permanently or for later removal of the cured reaction mixture. The application of the foamed reaction mixture to the substrate can be produced by techniques familiar to those skilled in the art, such as by doctor blade application, for example. It is preferred within the scope of the present invention if the foamed reaction mixture is coated in process step d) in a layer thickness of 50 - 50 000 pm, preferably in the range of 75 - 30 000 pm, even more preferably in the range of 100 - 10 000 pm, onto the carrier layer.

[0073] In process step e), the foamed reaction mixture coated onto the substrate is cured, thereby affording the polyurethane froth foam. According to the invention, this curing is preferably carried out at elevated temperatures of at least 50°C, preferably of at least 60°C, more preferably of at least 70°C. Furthermore, it is possible to dry the foamed reaction mixture coated onto the substrate in several stages at different temperatures. Corresponding drying techniques are widespread in industry and are known to those skilled in the art.

[0074] Another subject of the present are polyurethane froth foams comprising a composition according to the invention produced by the method according to the invention. Preferably, a polyurethane froth foam of this kind has an average cell size of up to 500 pm, preferably of up to 350 pm, in particular preferably of up to 300 pm. The average cell size can preferably be determined by microscopy, preferably by electron microscopy. For this purpose, a cross section of the porous polymer coating is viewed by means of a microscope with sufficient magnification and the size of at least 25 cells is ascertained. In order to obtain sufficient statistics for this evaluation method, the magnification of the microscope chosen should preferably be such that at least 10 x 10 cells are present in the observation field. The average cell size is then calculated as the arithmetic average of the cells or cell sizes viewed. This determination of cell size by means of microscopy is familiar to those skilled in the art.

[0075] Another subject of the present invention is the use of a polyurethane froth foam according to the invention for producing floor coverings such as carpets, footfall sound insulation or artificial turf, for producing textile coatings or sealing materials, and for producing oscillation and vibration damping mats and also volume tolerance pads, especially for use in electrical components and electric-car batteries.

[0076] Synthesis examples:

[0077] Step a) Production of the polyether polyols

[0078] Example a1 (inventive) - Reaction of a polyetheramine with glucono-1 ,5-lactone:

[0079] A 2-litre reaction vessel was charged with 918.2 g of a polyetheramine (= Jeffamine M-2070 from Huntsman, average molar mass 2000 g / mol, approx. 33 mol oxyethylene units, approx. 10 mol oxypropylene units). After inerting with nitrogen, the polyetheramine was heated to 90°C. Subsequently, 81.8 g of solid glucono-1 ,5-lactone were added in portions with stirring in 15 min. The mixture was stirred at 90°C for a further 5 h. The result was a homogeneous liquid reaction product. According to the13C-NMR spectrum, glucono-1 ,5-lactone was quantitatively reacted to the desired amide with ring opening. The resulting polyether polyol has 5 hydroxyl groups.

[0080] Step b) Preparation of the polyethers containing carboxyl groups

[0081] Example b1 (inventive): Reaction of the polyether polyol with maleic anhydride

[0082] A 2-litre reaction vessel was charged with 450 g of the polyether polyol from experiment a1 . After inerting with nitrogen, the polyether polyol was heated to 90°C. Subsequently, 40.5 g of solid maleic anhydride were added in portions with stirring in 20 min. The reaction temperature was increased to 120°C and the mixture was stirred at 120°C for a further 4 h. The result was a homogeneous liquid reaction product. According to13C-NMR spectrum, maleic anhydride was quantitatively reacted to the desired carboxyl group- bearing polyether with ring opening. The resulting polyether has an average of 2 carboxyl groups and 3 hydroxyl groups.

[0083] Example b2 (inventive): Reaction of the polyether polyol with phthalic anhydride

[0084] A 2-litre reaction vessel was charged with 500 g of the polyether polyol from experiment a1 . After inerting with nitrogen, the polyether polyol was heated to 90°C. Subsequently, 68.0 g of solid phthalic anhydride were added in portions with stirring in 30 min. The reaction temperature was increased to 140°C and the mixture was stirred at 140°C for a further 4.5 h. The result was a homogeneous liquid reaction product. According to13C-NMR spectrum, phthalic anhydride was quantitatively reacted to the desired carboxyl group-bearing polyether with ring opening. The resulting polyether has an average of 2 carboxyl groups and 3 hydroxyl groups.

[0085] Application examples:

[0086] Materials

[0087] Voranol® CP 3322 polyether-triol, OHN = 56 mg KOH / g, from DOW Voralux® HN 615 SAN polymer polyetherol, OHN = 30 mg KOH / g, from DOW

[0088] DPG dipropylene glycol, OHN = 836, from Sigma Aldrich

[0089] NiAcAc nickel(ll) acetylacetonate dihydrate, from Sigma Aldrich, dissolved at 10% in DPG

[0090] Tegostab® B 89120 polyether siloxane-based froth-foam stabilizer, from Evonik

[0091] Fe(lll) carboxylate iron(lll) neodecanoate dissolved in isopropyl myristate with an iron content of 5.0 wt.%

[0092] Omya® BLS calcium carbonate, from Omya

[0093] Suprasec® 6505 polymeric MDI, NCO-% = 29.3%, from Huntsman

[0094] For producing the catalytically active preparations Fe(lll) carboxylate and carboxyl group-functionalized polyethers were added to a 250 ml round-bottomed flask and then homogenized with stirring for 6 hours at 80°C. Table 1 gives an overview of the composition of these preparations.

[0095] Table 1 : Overview of the catalytically active compositions

[0096] Catalyst #1 Catalyst #2 inventive inventive

[0097] Iron(lll) carboxylate 50 g 50 g

[0098] Maleic acid-functionalized polyether

[0099] 122 g

[0100] (from Synthesis Example b1)

[0101] Phthalic acid-functionalized polyether

[0102] 122 g

[0103] (from Synthesis Example b2)

[0104] Optical appearance homogeneous mixture homogeneous mixture

[0105] To evaluate the catalytic activity of the preparations according to the invention, curing experiments were carried out in a polyurethane system. The formulations set out in Table 2 were used for these experiments. For these experiments, all the constituents of the A component were first weighed out into a 250 ml beaker and then homogenized with the aid of a Speedmixer (type DAC 400.1 FVZ from Hauschild) at 2000 rpm for 1 minute. Subsequently, the B component was added and the mixture was homogenized again for 30 seconds at 2000 rpm using the Speedmixer. The reaction mixture was then transferred to two aluminium dishes. One of these dishes was left standing at room temperature for 60 minutes and the temperature development of the reaction mixture was checked at 15-minute intervals. There was additional evaluation as to whether there was a significant increase in the viscosity of the reaction mixture after these 60 minutes. The second dish was placed to cure for 20 minutes in a drying oven conditioned at 120°C. After this time, the dish was removed and cooled back down to room temperature. The Shore A hardness of the cured reaction mixture was then determined using a durometer type 3120 - M001 from Elcometer. The results obtained here are likewise recorded in Table 2. In addition to the catalytically active compositions according to the invention, a comparative measurement with nickel(ll) acetylacetonate as catalyst was also carried out. These experiments as well are set out in Table 2.

[0106] Table 2: Overview of the composition of curing experiments

[0107] Experiment #1 Experiment #2 Experiment #3

[0108] Comparative exper- inventive inventive iment

[0109] Component A: Voranol CP 3322 60.9 g 10 g 10 g

[0110] Voralux HN 615 26.1 g 87 g 87 g

[0111] DPG 13.0 g 3 g

[0112] NiAcAc 2 g

[0113] Catalyst #1 1 .25 g

[0114] Catalyst #2 1 .25 g

[0115] Component B: Suprasec 6506 39.8 g 39.8 g 39.8 g

[0116] NCO Index 105 105 105

[0117] 0 minutes 31.5°C 29.2°C 30.8°C

[0118] Temperature of

[0119] 15 minutes 38.2°C 34.9°C 36.4°C reaction mixture

[0120] 30 minutes 38.4°C 36.9°C 36.6°C at room tempera-

[0121] 45 minutes 34.4°C 32.4°C 31.8°C ture after

[0122] 60 minutes 31.2°C 29.8°C 30.7°C

[0123] Viscosity of reaction mixture at room no noticeable in- no noticeable in- no noticeable intemperature after 60 minutes crease in viscosity crease in viscosity crease in viscosity

[0124] Shore A hardness after curing 57 56 59

[0125] As is evident from the compilation in Table 2, the preparations according to the invention show pronounced thermolatent reaction characteristics. Thus, at room temperature, almost no catalytic activity can be observed, as apparent from the fact that both the temperature and the viscosity of the reaction mixture change only insignificantly over a period of 60 minutes. In contrast, the preparations according to the invention show a very high catalytic activity at 120°C and lead to an efficient through-curing of the reaction mixture. The catalytic activity of the preparations according to the invention here is almost identical to that of nickel(ll) acetylacetonate, which has until now been an industry standard for thermolatent catalysts, but for toxicological reasons has to be considered critically. Production of froth foams

[0126] Froth foams were produced using a fully automatic laboratory foam generator, of type Pico-Mix XL from Hansa-Mixer, equipped with 2 separate eccentric-spiral hopper pumps. For these experiments, the A component of the reaction mixture (batch size approx. 5 kg) was first formulated and homogenized by means of a laboratory dissolver. The A component was then filled into one of the two hopper pumps of the foam generator. The other hopper pump was filled with the B component. The formulation described in Table 3 was used here. For foaming experiments, polyol premix and isocyanate were simultaneously injected into the mixing head of the foam generator and foamed therein by simultaneous introduction of nitrogen. The mixing head was operated here at 850 rpm in all experiments. The delivery rates of the two hopper pumps were constantly adjusted such that polyol and isocyanate were injected into the mixing head in the appropriate ratio (corresponding to the NCO index of the formulation), with a total mass flow rate of 9 kg / h. The air flow into the mixing head was selected so as to obtain foam densities of 300 g / l after foaming. The foamed reaction mixture was then coated (layer thickness 6 mm) onto a coated release paper using a laboratory coating table / dryer, Labcoater LTE-S from Mathis AG, and cured at 120°C for 15 min.

[0127] Table 2: Overview of the composition of curing experiments. All amounts stated are in parts by weight.

[0128] Experiment #1 Experiment #2 Experiment #3

[0129] Comparative exper- inventive inventive iment

[0130] Component A: Voranol CP 3322 140 140 140

[0131] Voralux HN 615 60 60 60

[0132] DPG 30 30 30

[0133] Tegostab B 89120 4 4 4

[0134] NiAcAc 4.5

[0135] Catalyst #1 2.9

[0136] Catalyst #2 2.9

[0137] Component B: Suprasec 6506 < Index = 105 >

[0138] In these experiments it could be shown that the catalytically active preparations according to the invention can be used excellently for the production of polyurethane froth foams. Thus the reaction mixture could easily be mechanically foamed to a foam and then coated onto a release paper. Reactivity or temperature development of the mixture was not observed during these steps. After the foams had cured at 120°C, however, an efficient curing behaviour could be observed. In all cases, well through-cured foams with pronounced elastic properties were obtained. On closer examination of the foams, it was also noted that the catalytically active preparations according to the invention have no effect on the cell structure of the foams. In this series of experiments as well, no difference between the catalytically active preparations and nickel(ll) acetylacetonate could be observed.

Claims

Claims1 . Composition for thermolatent catalysis in the production of at least one polyurethane, comprisingI) at least one metal compound;II) at least one polyether comprising at least one carboxyl group, characterized in that the at least one polyether comprising at least one carboxyl group is obtained by i) the reaction of at least one polyetheramine comprising at least one primary amino group with at least one hydroxy-functional lactone or at least one hydroxy-functional cyclic carbonate; and ii) reaction of the at least one reaction product from method step i) with at least one cyclic carboxylic anhydride.

2. Composition according to Claim 1 , characterized in that the at least one metal compound is selected from the group consisting of tin compounds, zinc compounds, bismuth compounds, iron compounds, copper compounds, nickel compounds, zirconium compounds, aluminium compounds, titanium compounds and mixtures of the aforesaid.

3. Composition according to either of Claims 1 and 2, characterized in that the at least one metal compound is in the form of oxide, hydroxide, oxide-hydroxide, sulfate, halide, carbonate or carboxylate.

4. Composition according to any of the preceding claims , characterized in that the at least one polyetheramine corresponds to the formula (1):whereR is a hydrocarbon radical having 1 to 4 carbon atoms, preferably a methyl radical;Y and Z are selected from the group consisting of hydrogen and methyl radical, with the condition that one of Y and Z is hydrogen and the other is a methyl radical; m is an integer from the interval from 0 to 100; n is an integer from the interval from 0 to 100; with the proviso that the sum total of m and n is 5 to 200.

5. Composition according to either of Claims 3 and 4, characterized in that the at least one polyetheramine has a mass-weighted average molar weight (Mw) in the range from 400 g / mol to 5000 g / mol, preferably in the range from 500 g / mol to 3000 g / mol, more preferably in the range from 1000 g / mol to 2500 g / mol.

6. Composition according to any of Claims 3 to 5, characterized in that the at least one polyetheramine has a polydispersity (Mw / Mn) in the range from 1 .01 to 3, preferably in the range from 1 .02 to 2, more preferably in the range from 1 .03 to 1 .5.

7. Composition according to any of Claims 3 to 6, characterized in that the at least one hydroxy-functional lactone is of a polyhydroxycarboxylic acid, more particularly of a sugar acid, C5-C6 sugar, and very preferably is glucono-1 ,5-lactone.

8. Composition according to any of Claims 3 to 7, characterized in that the at least one hydroxy-functional cyclic carbonate is glycerol 1 ,2-carbonate.

9. Composition according to any of Claims 3 to 8, characterized in that the at least one cyclic carboxylic anhydride is selected from the group consisting of maleic anhydride, succinic anhydride and phthalic anhydride.

10. Composition according to any of the preceding claims, characterized in that the at least one polyether comprising at least one carboxyl group has on average 1 .0 to 5.0 carboxyl groups, preferably 1 .3 to 4.0 carboxyl groups, particularly preferably 1 .5 to 3.5 carboxyl groups, more particularly 1 .7 to 2.5 carboxyl groups.11 . Composition according to any of the preceding claims, characterized in that the at least one poly- ether comprising at least one carboxyl group corresponds to the formula (2):where R, Y, Z, m and n have the meanings defined in the preceding claims and are subject to the conditions defined therein; andX is selected from the building blocks of the formulae (3a), (3b) and (3c):whereeach B is independently selected from the group consisting of hydrogen atom and the building blocks according to one of the formulae (4a), (4b) and (4c):

12. Method for producing at least one polyurethane, comprising the reaction of at least one isocyanate and at least one polyol in the presence of the composition according to any of Claims 1 to 11.

13. Polyurethane, preferably a polyurethane foam, more particularly a polyurethane froth foam, obtained by reacting at least one isocyanate and at least one polyol in the presence of the composition according to any of Claims 1 to 11 .

14. Use of at least one polyurethane, preferably a polyurethane foam, more particularly a polyurethane froth foam, according to Claim 13 for producing floor coverings, more particularly carpets, footfall sound insulation or artificial turf, textile coatings, - sealing materials, oscillation / vibration damping mats, or volume tolerance pads, especially for use in electrical components and electric-car batteries.

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