Polyisocyanates with improved properties

Abstract

The present invention relates to a method for preparing modified isocyanates by reacting at least one organic di- and / or triisocyanate in the at least temporary presence of component A1, which comprises at least one tetramethylammonium salt and / or at least one cyclic ammonium salt containing a cation of formula (I), in which Y is a linear or branched C2-C ring, which may carry other substituents and may be interrupted by heteroatoms from the group including oxygen, sulfur, nitrogen and aromatic rings, and which may carry other rings. 20 segment, and the substituent R at the N-position 1 and R 2 are each independently the same or different, substituted or unsubstituted, optionally branched aliphatic C1-C 20 group, aromatic C6~C 20 Group or aromatic aliphatic C7-C 20 group or N-position substituent R 1 and R 2 together form a ring segment X, having the same or a different definition as given above for Y, and having a pK of less than 4.0 when a predetermined conversion is reached based on the total amount of NCO groups of the at least one organic di- and / or triisocyanate. S The reaction is stopped by the addition of a substoichiometric amount, based on the molar amount of the cation of formula (I) in component A1, of component A2, which contains at least one acidic compound other than HF, having a pK value of less than 4.0. The resulting modified isocyanate, optionally after purification, has a pK value of less than 4.0. S value and is mixed with component A3 which contains an acidic compound other than HF, and at least one acidic compound in components A2 and A3 may be the same or different. TIFF2026503859000015.tif37165

Description

[Technical Field]

[0001] The present invention relates to polyisocyanates having improved properties such as odorlessness, extremely low monomer content, good monomer stability, and low tendency to cloudiness. The present invention also relates to a process for producing these polyisocyanates having the improved properties themselves, their use for producing polyurethane bodies or coatings, and polyurethane bodies or coatings. The present invention further relates to one- or two-component systems comprising the polyisocyanates having the improved properties. [Background technology]

[0002] The oligomerization or polymerization of isocyanates to form high molecular weight oligomer mixtures, in particular those having uretdione ("dimer"), isocyanurate ("trimer") and / or iminooxadiazinedione structures ("asymmetric trimers") in the molecular structure, has been known for a long time. As can be seen from the above, the oligomerization and polymerization of isocyanates are based in principle on the same chemical reaction. The reaction of a relatively small number of isocyanates with one another is called oligomerization. The reaction of a relatively large number of isocyanates is called polymerization. In the context of the present invention, the above-mentioned oligomerization or polymerization of isocyanates is collectively referred to as isocyanate modification or isocyanate modification.

[0003] Modified polyisocyanates containing free NCO groups, which may be temporarily quenched with blocking agents, are very high quality starting materials for the production of numerous polyurethane plastic and coating compositions.

[0004] A series of industrial processes for isocyanate modification has been established, in which the isocyanates to be modified, usually diisocyanates, are generally reacted by adding a catalyst, and then, when the desired conversion of the isocyanates to be modified is reached, they are deactivated (quenched) by appropriate means, and the resulting polyisocyanates are generally separated from the unreacted monomers. An overview of these processes from the prior art can be found in HJ Laas et al., J. Prakt. Chem. 1994, 336, 185 ff.

[0005] Compounds of ionic composition have proven effective as modification catalysts since they can be used in very small amounts compared to the monomers to be converted and produce the desired results very quickly, the cation being important in particular in view of the solubility of the respective salts in the isocyanate medium.

[0006] WO 2015 / 124504 and WO 2017 / 029266 describe highly stable ammonium salts in which the charged nitrogen atom forms part of a ring system.However, these compounds have the drawback of being poorly soluble in isocyanate-functional polyisocyanate resins, and therefore may cause cloudiness in the final process product.

[0007] According to the teachings of WO 2021 / 122508, this problem is avoided by incorporating a hydroxyl functional group into the catalyst molecule. However, special hydroxyl functional ammonium salts are not commercially available and have the disadvantage that their synthesis is very expensive and complicated. Inexpensive hydroxyl functional ammonium salts in which the hydroxyl functional group is not attached to a carbon atom of a charge-carrying nitrogen-containing cycle do not offer any advantages in the context of the present invention. That is, they do not exhibit any odor-free or destructive catalyst decomposition product-free monomers, which are typically recycled in this process. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2015 / 124504 [Patent Document 2] International Publication No. 2017 / 029266 [Patent Document 3] International Publication No. 2021 / 122508 [Non-patent literature]

[0009] [Non-Patent Document 1] HJLaas et al.,J.Prakt.Chem.1994,336,185 ff Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, it was an object of the present invention to provide polyisocyanates having improved properties such as no odor, an extremely low monomer content of less than 0.1% by weight, high back-cleavage stability, and low tendency to cloudiness, etc. In particular, it was an object of the present invention to provide polyisocyanates having a high content of iminooxadiazinedione structures and the above-mentioned improved properties. [Means for solving the problem]

[0011] In light of this need, a first subject of the present invention relates to a method for preparing modified isocyanates, in which at least one organic di- and / or triisocyanate is reacted in the at least temporary presence of a component A1 comprising at least one tetramethylammonium salt and / or at least one cyclic ammonium salt having a cation of formula I,

[0012] [ka] During the ceremony, Y may have further substituents and may be interrupted by heteroatoms from the group of oxygen, sulfur, nitrogen and aromatic rings, and may contain further rings. 20 Segment, Nitrogen Substituent R 1 and R 2 are independently the same or different, substituted or unsubstituted, optionally branched aliphatic C1-C 20 Radicals, aromatic C6-C 20 Radical or aromatic aliphatic C7-C 20 represents a radical, or Nitrogen Substituent R 1 and R 2 together form a ring segment X to which the same or different definition of Y above applies, and the reaction is carried out at a pK a and the addition of component A2, which comprises at least one acidic compound different from HF and has a pK value of less than 4.0, in a substoichiometric amount based on the molar amount of the cation of formula I in component A1, is completed by achieving a predetermined conversion based on the total amount of NCO groups of the at least one organic di- and / or triisocyanate, and the resulting modified isocyanate, optionally after further purification, has a pK value of less than 4.0. a and component A3, which contains at least one acidic compound different from HF, and the at least one acidic compound in components A2 and A3 may be different or identical to each other.

[0013] Also in light of this need, one subject of the present invention relates to a catalyst kit for isocyanate modification comprising three separate components A1, A2 and A3, a) component A1 contains at least one tetramethylammonium salt and / or at least one cyclic ammonium salt having a cation of formula I,

[0014] [ka] During the ceremony, Y may have further substituents and may be interrupted by heteroatoms from the group of oxygen, sulfur, nitrogen and aromatic rings, and may contain further rings. 20 Segment, Nitrogen Substituent R 1 and R 2 are independently the same or different, substituted or unsubstituted, optionally branched aliphatic C1-C 20 Radicals, aromatic C6-C 20 Radical or aromatic aliphatic C7-C 20 represents a radical, or Nitrogen Substituent R 1 and R 2 together form a ring segment X to which the same or different definition of Y above applies, b) Component A2 is used in a substoichiometric amount based on the molar amount of the cation of formula I in component A1 and has a pK of less than 4.0 a and comprising or consisting of at least one acidic compound different from HF, c) Component A3 has a pK of less than 4.0 a and contains at least one acidic compound different from HF, the at least one acidic compound in components A2 and A3 being the same or different from each other.

[0015] Also in light of this need, one subject of the present invention relates to the use of at least one catalyst kit according to the invention for modifying isocyanates and preventing the turbidity of the modified isocyanates.

[0016] References to "comprises", "contains" etc. preferably indicate "consist essentially of" and very particularly preferably "consist of". The further embodiments described in the claims and in the description can be combined as desired, in particular between different subject matters according to the invention, unless the contrary is clear from the context.

[0017] As used herein, "at least one" refers to one or more, e.g., two, three, four, five, six, seven, eight, nine, or more. In the context of the compound compositions described herein, this number does not refer to the absolute number of molecules, but rather to the nature of the composition. Thus, "at least one cyclic ammonium salt" should be understood to mean, for example, that only one type of cyclic ammonium salt or two or more different types of cyclic ammonium salts can be present, without specifying the amount of each compound.

[0018] Numerical values ​​specified herein without decimal points in each case refer to the full value specified to one decimal point, e.g., "99%" means "99.0%".

[0019] Numerical ranges given in the format "of x to y" are inclusive of the recited values. When multiple preferred numerical ranges are specified in this format, it goes without saying that all ranges formed by combining the different endpoints are also encompassed.

[0020] For polyprotic acids, pK a The values ​​are considered to be the lowest in this case, for example, pKa1 of 2.16 for phosphoric acid, rather than the further values ​​pKa2=7.20 and pKa3=12.33.

[0021] The term "aliphatic" is defined herein to mean a non-aromatic hydrocarbon group that is saturated or unsaturated.

[0022] The term "araliphatic" is defined herein to mean a hydrocarbon radical comprised of both aromatic hydrocarbon groups and saturated or unsaturated hydrocarbon groups directly bonded to an aromatic radical.

[0023] The terms "alicyclic" or "cycloaliphatic" are defined herein to mean optionally substituted carbocyclic or heterocyclic compounds or units that are not aromatic (e.g., cycloalkanes, cycloalkenes, or oxa-, thia-, aza-, or thiazacycloalkanes). Particular examples are the cyclohexyl group, the cyclopentyl group, and their N- or O-heterocyclic derivatives, such as pyrimidine, pyrazine, tetrahydropyran, or tetrahydrofuran.

[0024] Where a group or compound is disclosed as being "optionally substituted" or "substituted," suitable substituents are -F, -Cl, -Br, -I, -OCH3, -OCH2CH3, -O-isopropyl or -O-propyl, -OCF3, -CF3, -S-C1-6-alkyl, and / or linear or branched aliphatic and / or alicyclic structural units having 1 to 12 carbon atoms (optionally via pendant heteroatoms), in each case functioning as substituents for carbon-bonded hydrogen atoms of the respective molecule. Preferred substituents are halogen (especially -F, -Cl), C1-C6-alkoxy (especially methoxy and ethoxy), trifluoromethyl, and trifluoromethoxy, in each case functioning as substituents for carbon-bonded hydrogen atoms of the respective molecule.

[0025] According to the invention, component A1 contains at least one tetramethylammonium salt and / or at least one cyclic ammonium salt having a cation of formula I, with cyclic ammonium salts having a cation of formula I being preferred.

[0026] In a first preferred embodiment, Y represents an alkylene chain segment containing 4 to 7 members together with a charge-carrying nitrogen atom, which may carry further substituents.

[0027] In an equally preferred embodiment, R 1 and R 2represents, together with the charge-carrying nitrogen atom, a ring segment X which is the same as or different from Y, and X is a C4-C6-alkylene chain segment which may carry further substituents.

[0028] In a further preferred embodiment, segment Y and / or ring segment X have a linear structure.

[0029] Nitrogen Substituent R 1 and R 2 The cations of formula I, in which X and X together form a ring system or ring segment X, are spirocyclic compounds. The latter can be easily obtained by reaction of a secondary amine, the nitrogen atom of which is part of the ring system, with an appropriately substituted dihaloalkane, followed by anion exchange. A preferred route for their efficient synthesis is evident from Example 1.

[0030] In formula I, X and Y may each independently represent an optionally substituted alkylene group, and in particular, C4-C6 alkylene chains in both N-centered rings are preferred. The C4-C6 alkylene chains preferably have a linear structure. These can be easily obtained, for example, by reacting optionally C-substituted pyrrolidine, piperidine, and azepane (1H-hexahydroazepine) with optionally substituted 1,4-, 1,5-, and 1,6-dihaloalkanes, where halogen represents Cl, Br, or I, preferably Cl.

[0031] Furthermore, for example, by analogous reactions of optionally C-substituted oxazolidines, isoxazolidines, oxazinanes, morpholines, and oxazepanes, as well as analogs of the above-mentioned NO heterocycles containing S instead of O, as well as imidazolidines, pyrazolidines, piperazines, and structurally related compounds, with the above-mentioned dihaloalkanes, it is also possible to obtain representatives having a C chain interrupted by a heteroatom in one of the X or Y segments of general formula I. In the case of species containing two or more nitrogen atoms, it is also possible, by appropriate modification of the reaction conditions, to prepare salts with doubly or multiply charged cations, or, by appropriate prior substitution of the nitrogen atoms, to arrive at a single positively charged cation of formula I in which one or more exocyclic alkyl substituents are present on the trivalent nitrogen atom of ring X or Y.

[0032] It will be appreciated that by appropriate selection of the alkylating agent, it is also possible to introduce structural variations into the ring segments X or Y. An example is the reaction of alpha-omega-dihaloalkyl ethers with the secondary amines mentioned above.

[0033] In a further preferred embodiment, R 1 and R 2 independently represent identical or different C1-C8-alkyl substituents or identical or different benzyl radicals which may be substituted with an aromatic ring, preferably identical or different C1-C6-alkyl substituents, particularly preferably identical or different C1-C6-alkyl substituents with a linear structure, very particularly preferably methyl.

[0034] The anions used in the compounds of formula I may in principle be of any structural type known to be catalytically active towards isocyanates, with hydroxides, alkanoates, carboxylates, heterocycles having at least one negatively charged nitrogen atom in the ring, in particular azolates, imidazolates, triazolates, tetrazolates, fluorides, hydrogen difluoride, higher polyfluorides or mixtures thereof (adducts of more than one equivalent of HF onto compounds containing fluoride ions) being preferred, with fluorides, hydrogen difluorides and higher polyfluorides leading, according to the invention, to products with a high content of iminooxadiazinedione groups.

[0035] The catalysts of component A1 that can be used according to the invention can be used individually or in any desired mixture with one another. For example, the pK of the base and alcohol used can be a Depending on the value, solutions of quaternary ammonium hydroxides in various alcohols will exist partially or completely as ammonium salts with the alkoxide anion. This equilibrium can be shifted completely toward complete alkoxide formation by removing the water of reaction resulting from the reaction.

[0036] In the process according to the invention, it may further be provided that the oligomerization is carried out in the presence of a solvent.

[0037] To carry out the process according to the invention, it is possible in principle to use any known mono-, di- or polyisocyanates from the prior art, either individually or in any desired mixtures with one another.

[0038] Examples include pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 2-methylpentane 1,5-diisocyanate (MPDI), 2,4,4-trimethylhexane 1,6-diisocyanate and 2,2,4-trimethylhexane 1,6-diisocyanate (TMDI), 4-isocyanatomethyloctane 1,8-diisocyanate (nonane triisocyanate, NTI), 3(4)-isocyanatomethyl-1-methylcyclohexyl isocyanate (IMCI), isophorone diisocyanate (IPDI), 1,3- and 1,4-bis(isopropyl methyl ether) These include (cyanatomethyl)benzene (XDI), 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane (H6XDI), norbornane diisocyanate (NBDI), tolylene 2,4- and 2,6-diisocyanate (TDI), bis(4-isocyanatophenyl)methane (4,4'MDI), 4-isocyanatophenyl-2-isocyanatophenylmethane (2,4'MDI), and polycyclic products obtainable by formaldehyde-aniline polycondensation and subsequent conversion of the resulting (poly)amines to the corresponding (poly)isocyanates (polymeric MDI).

[0039] Aromatic diisocyanates, i.e., both NCO groups are sp 2 Diisocyanates bonded to hybridized carbon atoms, or aliphatic diisocyanates, i.e., both NCO groups are sp 3 Diisocyanates bonded to hybridized carbon atoms are preferred.

[0040] Particular preference is given to PDI, HDI, MPDI, TMDI, NTI, IPDI, IMCI, XDI, H6XDI, MDI or NBDI, with very particular preference being given to pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane (H6XDI) and / or norbornane diisocyanate (NBDI).

[0041] The method of producing the isocyanates, ie, with or without the use of phosgene, is not critical.

[0042] The amount of catalyst of component A1 that can be used in the process according to the invention is guided primarily by the organic isocyanate used and the desired reaction rate and is preferably from 0.001 to 5 mol %, preferably from 0.002 to 2 mol %, based on the sum of the molar amounts of isocyanate and catalyst used.

[0043] In the method according to the present invention or the catalyst kit according to the present invention, the catalyst may be used undiluted or dissolved in a solvent.Solvents useful herein include all compounds that do not react with the catalyst and can dissolve it to a sufficient extent, such as optionally halogenated aliphatic or aromatic hydrocarbons, alcohols, ketones, esters and ethers.It is preferable to use alcohols.

[0044] The process according to the present invention can be carried out at a temperature in the range of 0°C to +250°C, preferably 20°C to 200°C, particularly preferably 40°C to 150°C, and can be interrupted at any conversion rate of the isocyanate used, preferably 5% to 80%, particularly preferably 10% to 60%.

[0045] Termination of the reaction (hereinafter also referred to as catalyst deactivation or termination of the catalyzed isocyanate oligomerization) can be achieved by any desired method; it is essential to the present invention that the chemical deactivation of the catalyst is carried out in at least two stages in order to arrive at products according to the invention which have a low tendency to crystallization and a low residual monomer content.

[0046] Thus, according to the present invention, the termination of the catalyzed isocyanate oligomerization is carried out by using at least one catalyst poison (hereinafter also referred to as "terminator" and collectively as component A2) in an amount that is substoichiometric relative to the catalyst used but sufficient to terminate the catalytic reaction, and then adding a second dose of the same or a different catalyst poison as component A3 to the product according to the present invention with a low residual monomer content, preferably after monomer separation by distillation. The amount of component A3 added as the second dose (hereinafter also referred to as "stabilizer") can be freely selected within a wide range and is preferably added in a stoichiometric, particularly preferably superstoichiometric, molar amount based on the calculated molar amount of the cation of formula I in component A1 remaining after subtracting the amount already present as component A2. The term "superstoichiometric" should preferably be understood to mean that the catalyst poison should be added to component A1 in a molar amount that is not more than twice the molar amount of the cation of formula I.

[0047] Only this procedure according to the invention makes it possible to produce products with extremely low monomer content and high back-cleavage stability over the long term, as well as mild odor and crystallization-stable products at low temperatures and / or when using lacquer solvents typical for polyisocyanate resins. Furthermore, the process according to the invention also benefits from a more uniform catalyst consumption without drift, as well as significantly improved process stability due to a lower tendency for caking, turbidity and solids separation in the plant.

[0048] Suitable terminators generally have a pK a acidic compounds having a value different from HF, such as alkanesulfonic acids and arylsulfonic acids, such as naphthalene monosulfonic and disulfonic acids, toluenesulfonic acid, dodecylbenzenesulfonic acid, methanesulfonic acid, phosphoric acid and acidic esters of phosphoric acid, such as dibutyl phosphate and / or monobutyl phosphate, and any desired mixtures of the aforementioned compounds.

[0049] In a preferred embodiment, component A2 and / or the at least one acidic compound is selected from the group comprising or consisting of alkanesulfonic acids and arylsulfonic acids, such as naphthalenemonosulfonic acid and naphthalenedisulfonic acid, toluenesulfonic acid, dodecylbenzenesulfonic acid, methanesulfonic acid, phosphoric acid and acidic esters of phosphoric acid, such as dibutyl phosphate and / or monobutyl phosphate, and any desired mixtures of the aforementioned compounds, preferably aromatic sulfonic acids, particularly preferably dodecylbenzenesulfonic acid and toluenesulfonic acid.

[0050] In a further preferred embodiment, the unconverted organic isocyanate is removed after deactivation of the catalyst system by any desired method from the prior art, such as (thin film) distillation or extraction, and is preferably then reused (recycled).

[0051] Regardless of the anion responsible for catalytic activity and selectivity, the catalysts according to the invention containing cyclic segments are generally substantially more stable in the organic isocyanates reacted with than the prior art open-chain derivatives known from the literature, which may result in drawbacks in industrial performance due to low solubility and turbidity of the catalyst resultant product in polyisocyanates, but may also result in advantages due to reduced contamination of recyclable monomers with N-containing cleavage products from decomposition of the cation.

[0052] In a particular continuous operation embodiment of the process according to the invention, the oligomerization may be carried out continuously, for example in a tubular reactor.

[0053] The modification process according to the invention makes it possible to obtain a wide range of modified isocyanates that are very generally of high quality and therefore of great value for the polyurethane sector. The invention further provides modified isocyanates that can be obtained or produced by the process according to the invention.

[0054] Depending on the starting (di)isocyanate used and the reaction conditions, the process according to the invention gives polyisocyanates known as isocyanate trimer types (i.e., containing isocyanurate and / or iminooxadiazinedione structures) with a low proportion of uretdione groups ("isocyanate dimers"). The proportion of uretdione groups in the process products generally increases with increasing reaction temperature.

[0055] According to the present invention, polyisocyanates with a high iminooxadiazinedione content that can be obtained by polyfluoride catalysis are preferred. The term "high iminooxadiazinedione content" should be understood to mean at least 30 mol%, preferably more than 35 mol%, particularly preferably more than 40 mol%, based on the sum of isocyanurate groups and iminooxadiazinedione groups. The above-mentioned molar ratio can be determined, for example, by NMR spectroscopy (see the Examples section).

[0056] Thus, the product or product mixture obtainable by the process according to the invention is a versatile starting material for the production of optionally foamed plastics, as well as lacquers, coating compositions, adhesives, and additives. Therefore, the invention further provides the use of the modified isocyanates according to the invention for the production of foamed or non-foamed plastics, as well as lacquers, coating compositions, adhesives, and additives. Thus, the invention further provides polyurethane bodies obtainable or produced by reacting at least one monomeric diisocyanate and / or polyisocyanate with at least one polyol component in the presence of a catalyst component according to the invention. When foamed polyurethane bodies are concerned, PIR foams are preferred.

[0057] The process products according to the invention can be used by themselves or in combination with other prior art isocyanate derivatives, for example polyisocyanates containing uretdione, biuret, allophanate, isocyanurate and / or urethane groups, the free NCO groups of which may be deactivated with blocking agents.

[0058] The present invention further provides coatings that are obtainable or produced by one- or two-component systems containing component A) comprising at least one modified isocyanate according to the invention and component B) comprising at least one NCO-reactive compound, and by curing the one- or two-component systems according to the invention, optionally by heating and / or in the presence of a catalyst, as well as substrates coated with at least one one- or two-component system according to the invention, which may be cured by heating.

[0059] The surprising observation that the modified isocyanates of the present invention do not exhibit delayed clouding alone indicates that the products of the present invention must be distinguished from the prior art in terms of their structure and composition. The isocyanates modified according to the present invention differ in the cation (from component A1) to anion (from components A2 and A3) ratio, more precisely, the cation (from A1) to halide ratio, preferably the cation (from A1) to chloride and / or cation (from A1) to bromide ratio, and the cation (from A1) to anion (from A2 and / or A3) sulfonate ratio. In particular, in the cation (from A1) to anion (from A2 and / or A3) ratio, the anions resulting from A2 and / or A3 contain phosphorus and / or sulfur, preferably sulfur. This difference is reflected in the cured or formed polyurethane body. Therefore, composite components containing materials at least partially bonded to the polyurethane body or coating of the present invention are also the subject of the present invention.

[0060] In this case, the term "modified isocyanate" has the meaning defined at the beginning and preferably denotes a polyisocyanate having a statistical average of at least 1.5 NCO groups. Modified isocyanates according to the present invention are synonymous with modified isocyanate compositions, for example, since cations and anions are not separable.

[0061] The present invention particularly relates to the following embodiments:

[0062] In a first embodiment, the present invention relates to a method for preparing modified isocyanates, in which at least one organic di- and / or triisocyanate is reacted in the at least temporary presence of component A1, which comprises at least one tetramethylammonium salt and / or at least one cyclic ammonium salt having a cation of formula I,

[0063] [ka]

[0064] During the ceremony, Y may have further substituents and may be interrupted by heteroatoms from the group of oxygen, sulfur, nitrogen and aromatic rings, and may contain further rings. 20 Segment, Nitrogen Substituent R 1 and R 2 are independently the same or different, substituted or unsubstituted, optionally branched aliphatic C1-C 20 Radicals, aromatic C6-C 20 Radical or aromatic aliphatic C7-C 20 represents a radical, or Nitrogen Substituent R 1 and R 2 together form a ring segment X to which the same or different definition of Y above applies, The reaction has a pK of less than 4.0 aand completing the addition of a substoichiometric amount, based on the molar amount of the cation of formula I in component A1, of component A2, which comprises at least one acidic compound different from HF and having a value of 0.1 to 0.5, until a predetermined conversion is achieved based on the total amount of NCO groups of the at least one organic di- and / or triisocyanate, The resulting modified isocyanate (optionally after purification) has a pK of less than 4.0. a and component A3, which contains at least one acidic compound different from HF, and the at least one acidic compound in components A2 and A3 may be different or identical to each other.

[0065] In a second embodiment, the present invention provides a compound having R in the cation of formula I 1 and R 2 independently represent identical or different C1-C8-alkyl substituents or identical or different benzyl radicals which may be substituted with an aromatic ring, preferably identical or different C1-C6-alkyl substituents, particularly preferably identical or different C1-C6-alkyl substituents with a linear structure, very particularly preferably methyl, or R 1 and R 2 represents together with the charge-carrying nitrogen atom a ring segment X which is identical to or different from Y, and X is a C4-C6-alkylene chain segment which may carry further substituents.

[0066] In a third embodiment, the present invention relates to a method for preparing modified isocyanates according to embodiment 1 or 2, characterized in that Y in the cation of formula I represents an alkylene chain segment containing 4 to 7 members together with the charge-carrying nitrogen atom and optionally carrying further substituents, preferably segment Y and / or ring segment X having a linear structure.

[0067] In a fourth embodiment, the present invention relates to a method for preparing modified isocyanates according to any one of the first to third embodiments, characterized in that component A1 contains an anion selected from the group consisting of hydroxides, alkanoates, carboxylates, heterocycles with at least one negatively charged nitrogen atom in the ring, fluorides, hydrogen difluoride, higher polyfluorides, adducts of more than one equivalent of HF on compounds containing fluoride ions, and any desired mixtures thereof.

[0068] In a fifth embodiment, the present invention provides a method for preparing a soluble ... a The present invention relates to a method for producing a modified isocyanate according to any one of embodiments 1 to 4, characterized in that the modified isocyanate has a value.

[0069] In a sixth embodiment, the present invention relates to a method for preparing modified isocyanates according to any of the first to fifth embodiments, characterized in that component A3 (stabilizer) is added in a molar amount that is stoichiometric, preferably superstoichiometric, together with component A2 (terminator), based on the amount of cation of formula I in component A1.

[0070] In a seventh embodiment, the present invention relates to a method for preparing modified isocyanates according to any of the first to sixth embodiments, characterized in that at least one acidic compound of components A2 and / or A3 is selected from the group consisting of alkanesulfonic and arylsulfonic acids, such as naphthalenemonosulfonic acid and naphthalenedisulfonic acid, toluenesulfonic acid, dodecylbenzenesulfonic acid, methanesulfonic acid, phosphoric acid and acidic esters of phosphoric acid, such as dibutyl phosphate and / or monobutyl phosphate, and any desired mixtures of the aforementioned compounds, preferably aromatic sulfonic acids, particularly preferably dodecylbenzenesulfonic acid and toluenesulfonic acid.

[0071] In an eighth embodiment, the present invention relates to a method for preparing a modified isocyanate according to any one of the first to seventh embodiments, characterized in that the organic diisocyanate is selected from the group comprising or consisting of PDI, HDI, MPDI, TMDI, NTI, IPDI, IMCI, XDI, H6XDI, MDI, TDI or NBDI, preferably from the group comprising or consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane and / or norbornane diisocyanate.

[0072] In a ninth embodiment, the present invention relates to a catalyst kit for isocyanate modification comprising three components A1, A2 and A3, a) component A1 contains at least one tetramethylammonium salt and / or at least one cyclic ammonium salt having a cation of formula I,

[0073] [ka] During the ceremony, Y may have further substituents and may be interrupted by heteroatoms from the group of oxygen, sulfur, nitrogen and aromatic rings, and may contain further rings. 20 Segment, Nitrogen Substituent R 1 and R 2 are independently the same or different, substituted or unsubstituted, optionally branched aliphatic C1-C 20 Radicals, aromatic C6-C 20 Radical or aromatic aliphatic C7-C 20 represents a radical, or Nitrogen Substituent R 1 and R 2 together form a ring segment X to which the same or different definition of Y above applies, b) Component A2 has a pK of less than 4.0 avalue and, different from HF, comprises or consists of at least one acidic compound used in a substoichiometric amount based on the molar amount of the cation of formula I in component A1, c) Component A3 has a pK of less than 4.0 a and contains at least one acidic compound different from HF, the at least one acidic compound in components A2 and A3 being the same or different from each other.

[0074] In a tenth embodiment, the present invention provides a compound having R in a cation of formula I 1 and R 2 are independently the same or different C1-C8 alkyl substituents or the same or different benzyl radicals which may be substituted with an aromatic ring, preferably the same or different C1-C6 alkyl substituents, particularly preferably the same or different C1-C6 alkyl substituents having a linear structure, or R 1 and R 2 together with the charge-carrying nitrogen atom represent a ring segment X identical to or different from Y, and X is a C4-C6-alkylene chain segment optionally carrying further substituents.

[0075] In an eleventh embodiment, the present invention relates to a catalyst kit for isocyanate modification according to embodiment 9 or 10, characterized in that Y in the cation of formula I represents an alkylene chain segment containing 4 to 7 members together with the charge-carrying nitrogen atom and optionally carrying further substituents, preferably segment Y and / or ring segment X having a linear structure.

[0076] In a twelfth embodiment, the invention relates to a catalyst kit for isocyanate modification according to any of embodiments 9 to 11, characterized in that component A1 contains an anion selected from the group consisting of hydroxides, alkanoates, carboxylates, heterocycles having at least one negatively charged nitrogen atom in the ring, fluorides, hydrogen difluoride, higher polyfluorides, adducts of more than one equivalent of HF with compounds containing fluoride ions, and any desired mixtures thereof.

[0077] In a thirteenth embodiment, the present invention provides a method for preparing a soluble ... a 13. A catalyst kit for isocyanate modification according to any one of embodiments 9 to 12, characterized in that it has a value.

[0078] In a fourteenth embodiment, the present invention relates to a catalyst kit for isocyanate modification according to any of embodiments 9 to 13, characterized in that component A3 (stabilizer) is added in a molar amount that is stoichiometric, preferably superstoichiometric, together with component A2 (terminator), based on the amount of cation of formula I in component A1.

[0079] In a fifteenth embodiment, the invention relates to a catalyst kit for isocyanate modification according to any of embodiments 9 to 14, characterized in that at least one acidic compound of component A2 and / or A3 is selected from the group consisting of alkanesulfonic and arylsulfonic acids, such as naphthalene monosulfonic acid and naphthalenedisulfonic acid, toluenesulfonic acid, dodecylbenzenesulfonic acid, methanesulfonic acid, phosphoric acid and acidic esters of phosphoric acid, such as dibutyl phosphate and / or monobutyl phosphate, and any desired mixtures of the aforementioned compounds, preferably aromatic sulfonic acids, particularly preferably dodecylbenzenesulfonic acid and toluenesulfonic acid.

[0080] In a sixteenth embodiment, the present invention relates to the use of the catalyst kit according to at least one of embodiments 9 to 15 in isocyanate modification to prevent clouding of the modified isocyanate.

[0081] In a seventeenth embodiment, the present invention relates to a modified isocyanate obtainable or produced, preferably directly obtainable, by the method according to any of the first to eighth embodiments.

[0082] In an eighteenth embodiment, the present invention relates to a one-component system containing a modified isocyanate according to embodiment 17, in which the NCO groups are blocked, or to a two-component system comprising component 1) comprising at least one modified isocyanate according to embodiment 17, and component 2) comprising at least one NCO-reactive compound.

[0083] In a nineteenth embodiment, the present invention relates to a coating obtainable or produced by applying the one-component or two-component system according to embodiment 18 to a substrate and curing, optionally by heating and / or in the presence of a catalyst.

[0084] In a twentieth embodiment, the invention relates to a composite component comprising a material at least partially bonded to the coating of embodiment 19.

[0085] The following comparative examples and examples are intended to further illustrate the invention without limiting it.

[0086] [Example] All percentages should be understood to mean percent by weight unless otherwise specified.

[0087] Mole % values ​​are determined by NMR spectroscopy and always relate to the total NCO conversion products unless otherwise stated. Measurements were performed on a Bruker DPX 400 or DRX 700 instrument at approximately 5% ( 1 H NMR) or about 50% ( 13C NMR) samples at 400 or 700 MHz ( 1 H NMR) or 100 or 176 MHz ( 13 The reference used for the ppm scale was 0 ppm. 1 The H NMR chemical shift was determined to be a small amount of tetramethylsilane in the solvent. Alternatively, C6D5H present in the solvent was used as the reference signal: 1 H-NMR chemical shift 7.15 ppm, 13 C-NMR chemical shift 128.02 ppm. Chemical shift data for the compounds in question were obtained from the literature (see D. Wendisch, H. Reiff and D. Dieterich, Die Angewandte Makromolekulare Chemie 141, 1986, 173-183 and the references cited therein, and also EP-A-896009).

[0088] The dynamic viscosity was determined at 23°C using a Haake VT 550 viscometer in accordance with DIN EN ISO 3219:1994-10. Measurements at different shear rates ensured that the flow behavior of the polyisocyanate mixtures described according to the invention and of the comparative products corresponded to that of ideal Newtonian fluids. Therefore, the indication of the shear rate can be omitted.

[0089] The NCO content was determined by titration according to DIN EN ISO 11909:2007-05.

[0090] The residual monomer content was determined by gas chromatography according to DIN EN ISO 10283:2007-11 using an internal standard.

[0091] Unless otherwise stated, all reactions were carried out under a nitrogen atmosphere.

[0092] The diisocyanates used were products of Covestro AG, D-51365 Leverkusen, all other commercially available chemicals were supplied by Aldrich, D-82018 Taufkirchen.

[0093] Reactants that were not commercially available were obtained by methods known from the literature.

[0094] [Example 1] Catalyst production (not according to the present invention) A 2 L four-neck flask equipped with a stirrer and central condenser was initially charged with 61.7 g (1.1 mol) of KOH, 500 ml of deionized water, and 139.7 g (1.1 mol) of 1,4-dichlorobutane and heated with stirring to an oil bath temperature of approximately 100-110°C (gentle reflux).

[0095] After reaching the above internal temperature, 85.2 g (1 mol) of piperidine was added quickly enough to avoid excessive reflux.

[0096] Solid separation occurred already shortly after the start of piperidine addition. The reaction mixture was heterogeneous from the beginning (initially liquid-liquid, then three-phase liquid-liquid-solid, then solid-liquid), but always contained enough liquid phase to efficiently mix the majority of the reaction mixture.

[0097] After the addition of piperidine was complete, the mixture was stirred for an additional 2 hours at an oil bath temperature of 110-120° C. The reflux decreased significantly over this period.

[0098] Approximately 150 g of methanol was then added to the still hot mixture, and the latter was boiled under reflux until a fine suspension was formed. The mixture was then cooled to approximately 40°C, and approximately 87 g (1.5 mol) of solid KF was added, mixed with enough methanol (250-300 g, the exact amount is not critical) to ensure good stirrability.

[0099] The previously filtered liquid phase was then stirred at 40°C while occasionally monitoring chloride by argentometry, and then filtered. The filter residue was washed little by little with a total of about 400 g of 2-ethylhexanol (2-EH) preheated to about 40-50°C, and the combined filtrate was mixed with 50 g of 40% aqueous hydrofluoric acid (1 mol HF) while stirring and cooling so that the internal temperature did not exceed 40°C.

[0100] Once the HF addition was complete, the mixture was heated to reflux for 1 h, and then the apparatus was switched to distillate removal. When no more distillate was present at standard pressure and a bath temperature of 100 °C, the pressure was gradually reduced to 50 mbar, the bottom temperature was gradually increased up to 150 °C, and the resulting distillate was discontinuously discharged. Finally, the anhydrous distillate (2-EH) was obtained overhead.

[0101] After cooling, the target concentration (20%) was established by 2-EH addition, followed by filtration to remove small amounts of insoluble components. The total fluoride content of this clear, yellowish solution was 4.3% (ion-sensitive electrode; F from HF and fluoride from halogen exchange were captured as total fluoride). F from the HF addition was removed by 0.1 N NaOH (H from HF) relative to phenolphthalein. + Acid titration (as) determined at 2.1% and the residual chloride content (determined argentometrically) was 0.15%.

[0102] Other catalysts specified in Table 1 were correspondingly synthesized from the initially formed chloride by anion exchange (which may be followed by the addition of HF for the synthesis of di- / polyfluorides). Monocyclic ammonium salts 5-7 were synthesized by anion exchange similar to that shown above based on commercially available N,N-dimethylammonium chloride (which may be followed by the addition of HF for the synthesis of di- / polyfluorides).

[0103] [Table 1]

[0104] Example Series 2: Methods not according to the invention according to Examples Series 2-1 to 2-4 of EP-A-3107948 and Examples Series 2-5 to 2-7 of EP-A-3337836 The optimal catalyst concentration for diisocyanate trimerization was determined in exploratory preliminary tests at 60°C, and the concentration of the catalyst solution was adjusted by dilution with 2-EH such that negligible, if any, gel particle formation was observed when the catalyst solution was added to stirred HDI. A test series with distillate recycle on a 1 kg scale was then carried out as described below.

[0105] A double-walled flanged vessel, heated to the desired starting temperature in each case using an external circuit and equipped with a stirrer, a reflux condenser connected to an inert gas system (nitrogen / vacuum), and a thermometer, was initially charged with 1000 g of HDI. This was stirred under reduced pressure (<1 mbar) for 1 hour to remove dissolved gases. After gasification with nitrogen, the type and amount of catalyst specified in Table 2 was added at the concentration specified in Table 2, allowing the reaction to proceed in the temperature range of approximately 60°C to 65°C. After approximately 1 mol of NCO groups had been converted, as indicated by the achievement of an NCO content of approximately 45.8%, the catalyst was deactivated by adding an equivalent amount of a terminator specified in Table 2. The mixture was stirred at the reaction temperature for an additional 30 minutes and then worked up.

[0106] The workup was carried out by vacuum distillation in a flash evaporator (FE)-type thin-film evaporator with a pre-evaporator (PE) connected upstream (distillation data: pressure: 0.08 + / - 0.04 mbar, PE temperature: 120 °C, ME temperature: 140 °C). The unconverted monomer was separated as a distillate, and the low-monomer polyisocyanate resin was separated as a bottom product (start of run). The polyisocyanate resin was separated, and the distillate was collected in a second flanged stirrer identical to the first. The mixture was then re-treated with the catalyst, following the procedure described initially. This procedure was repeated several times (Tests A, B, C, etc.). After multiple recycle steps, it was observed that the amount of catalyst required to achieve the desired conversion was slightly higher in the first test of each series than in subsequent tests, but then increased continuously. Furthermore, especially for the products of the "later" recycling step (Test D below), a slowly developing cloudiness, sometimes accompanied by a slow increase in the residual monomer content, was observed for the polyisocyanate resins, especially during storage at relatively high temperatures, often only after several weeks of storage and / or after the addition of typical lacquer solvents such as xylene or solvent naphtha. According to the results of the combined analytical methods, the precipitate obtained after filtration was found to be essentially ammonium chloride (about 2 / 3 mole) and bromide (about 1 / 3 mole) of the catalyst used.

[0107] The results are clear from Table 2.

[0108] [Table 2] TIFF2026503859000008.tif54163

[0109] Example Series 3: According to the Invention The method was as specified in Example Series 2, except that after the target NCO content (approximately 45.8%) was achieved, the catalyst was deactivated by adding the amount of terminator specified in Table 3 (40-60 mol% based on the catalyst used) that was substoichiometric to the catalyst, the reaction mixture was stirred at the reaction temperature for an additional 30 minutes to ensure that the reaction was efficiently inhibited, and then the mixture was worked up as specified in Example Series 2.

[0110] The polyisocyanate resin isolated after each cycle was separated and then post-stabilized with less than 110% of the stoichiometric amount of stopper based on the catalyst used by stirring at 60°C for 1 hour after adding the stabilizer. Even after multiple recycling steps, no increase in the amount of catalyst required to achieve the target conversion was observed in each subsequent test. Furthermore, none of the resulting products showed delayed clouding of the polyisocyanate resin or an increase in residual monomer content under the conditions listed in Comparative Example Series 2.

[0111] The results are clear from Table 3.

[0112] [Table 3] TIFF2026503859000010.tif50162

[0113] Example Series 4: According to the Invention The procedure was as specified in Example Series 3, except that PDI (1,5-pentamethylene diisocyanate) was used instead of HDI, and after achieving the target NCO content (54.9%-55.1%), the catalyst was deactivated by the addition of the amount of terminator specified in Table 4 (40-60 mol% based on the catalyst used) that was substoichiometric to the catalyst, and the reaction mixture was stirred at the reaction temperature for an additional 30 minutes to ensure that the reaction was effectively inhibited, after which the mixture was worked up as specified in Example Series 2 / 3.

[0114] The polyisocyanate resin isolated after each cycle was separated and then post-stabilized with less than 110% of the stoichiometric amount of stopper based on the catalyst used by stirring at 60°C for 1 hour after adding the stabilizer. Even after multiple recycling steps, no increase in the amount of catalyst required to achieve the target conversion was observed in each subsequent test. Furthermore, none of the resulting products showed delayed clouding of the polyisocyanate resin or an increase in residual monomer content under the conditions listed in Comparative Example Series 2.

[0115] The results are clear from Table 4.

[0116] [Table 4] TIFF2026503859000012.tif53159

Claims

1. 1. A process for preparing modified isocyanates, comprising reacting at least one organic di- and / or triisocyanate in the at least temporary presence of component A1, which comprises at least one tetramethylammonium salt and / or at least one cyclic ammonium salt having a cation of formula I, 【Chemistry 1】 During the ceremony, Y is a linear or branched C alkyl group which may have further substituents and which may be interrupted by heteroatoms from the group of oxygen, sulfur, nitrogen and aromatic rings and which may contain further rings. ２ ~C ２０ Segment, Nitrogen Substituent R １ and R ２ are independently the same or different, substituted or unsubstituted, optionally branched aliphatic C １ ~C ２０ Radical, aromatic C ６ ~C ２０ Radical or araliphatic C ７ ~C ２０ represents a radical, or Nitrogen Substituent R １ and R ２ together form a ring segment X to which the same or different definition of Y above applies, The reaction has a pK of less than 4.0 ａ and completing the addition of a substoichiometric amount, based on the molar amount of the cation of formula I in component A1, of component A2, which comprises at least one acidic compound different from HF and has a value of 0.1 to 0.5, until a predetermined conversion is achieved based on the total amount of NCO groups of the at least one organic di- and / or triisocyanate, The resulting modified isocyanate, optionally after purification, has a pK of less than 4.

0. ａ and a component A3 having a value of 0.05 to 0.15 and containing at least one acidic compound different from HF, The method wherein the at least one acidic compound in components A2 and A3 can be the same or different.

2. R in the cation of formula I １ and R ２ are independently the same or different C １ ~C ８ - the same or different benzyl radicals, which may be substituted with alkyl substituents or aromatic rings, preferably the same or different C １ ~C ６ - alkyl substituents, particularly preferably the same or different C １ ~C ６ - represents an alkyl substituent, very particularly preferably methyl, or R １ and R ２ represents, together with the charge-carrying nitrogen atom, a ring segment X which may be the same as or different from Y, and X is a C ４ ~C ６ 2. The method according to claim 1, wherein the alkylene chain segment is an alkylene chain segment, which may carry further substituents.

3. 3. The method according to claim 1 or 2, characterized in that Y in the cation of formula I represents an alkylene chain segment containing 4 to 7 members together with the charge-carrying nitrogen atom and optionally carrying further substituents, preferably segment Y and / or ring segment X having a linear structure.

4. 3. The method according to claim 1 or 2, characterized in that component A1 contains an anion selected from the group consisting of hydroxides, alkanoates, carboxylates, heterocycles having at least one negatively charged nitrogen atom in the ring, fluorides, hydrogen difluoride, higher polyfluorides, adducts of more than one equivalent of HF with compounds containing fluoride ions, and any desired mixtures thereof.

5. At least one acidic compound in components A1 and / or A2 has a pK of less than 2.0 ａ 3. The method according to claim 1, wherein the value is a positive integer.

6. 3. The method according to claim 1 or 2, characterized in that component A3 (stabilizer) is added in a molar amount which is stoichiometric, preferably superstoichiometric, together with component A2 (terminator), based on the amount of the cation of formula I in component A1.

7. 3. The process according to claim 1 or 2, characterized in that at least one acidic compound of components A2 and / or A3 comprises or is selected from the group consisting of alkanesulfonic and arylsulfonic acids, such as naphthalene monosulfonic acid and naphthalenedisulfonic acid, toluenesulfonic acid, dodecylbenzenesulfonic acid, methanesulfonic acid, phosphoric acid and acidic esters of phosphoric acid, such as dibutyl phosphate and / or monobutyl phosphate, and any desired mixtures of the aforementioned compounds, preferably aromatic sulfonic acids, particularly preferably dodecylbenzenesulfonic acid and toluenesulfonic acid.

8. 3. The method according to claim 1 or 2, characterized in that the organic diisocyanate is selected from the group comprising or consisting of PDI, HDI, MPDI, TMDI, NTI, IPDI, IMCI, XDI, H6XDI, MDI, TDI or NBDI, preferably from the group comprising or consisting of pentamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane and / or norbornane diisocyanate.

9. A catalyst kit for isocyanate modification comprising three separate components A1, A2 and A3, a) component A1 contains at least one tetramethylammonium salt and / or at least one cyclic ammonium salt having a cation of formula I, 【Chemistry 2】 During the ceremony, Y is a linear or branched C alkyl group which may have further substituents and which may be interrupted by heteroatoms from the group of oxygen, sulfur, nitrogen and aromatic rings and which may contain further rings. ２ ~C ２０ Segment, Nitrogen Substituent R １ and R ２ are independently the same or different, substituted or unsubstituted, optionally branched aliphatic C １ ~C ２０ Radical, aromatic C ６ ~C ２０ Radical or araliphatic C ７ ~C ２０ represents a radical, or Nitrogen Substituent R １ and R ２ together form a ring segment X to which the same or different definition of Y above applies, b) Component A2 is used in a substoichiometric amount based on the molar amount of the cation of formula I in component A1 and has a pK of less than 4.0 ａ and containing or consisting of at least one acidic compound different from HF, c) Component A3 has a pK of less than 4.0 ａ and containing at least one acidic compound different from HF, The at least one acidic compound in components A2 and A3 may be the same or different.

10. 10. The catalyst kit according to claim 9, characterized in that at least one acidic compound of component A2 and / or A3 comprises or is selected from the group consisting of alkanesulfonic and arylsulfonic acids, such as naphthalene monosulfonic acid and naphthalenedisulfonic acid, toluenesulfonic acid, dodecylbenzenesulfonic acid, methanesulfonic acid, phosphoric acid and acidic esters of phosphoric acid, such as dibutyl phosphate and / or monobutyl phosphate, and any desired mixtures of the aforementioned compounds, preferably aromatic sulfonic acids, particularly preferably dodecylbenzenesulfonic acid and toluenesulfonic acid.

11. 11. Use of the catalyst kit according to at least claim 9 or 10 in isocyanate modification to prevent clouding of the modified isocyanate.

12. 3. A modified isocyanate obtainable or produced, preferably directly obtainable, by the method according to claim 1 or 2.

13. 13. A one-component system containing the modified isocyanate of claim 12, in which the NCO groups are blocked, or a two-component system containing component 1) comprising at least one modified isocyanate of claim 12 and component 2) comprising at least one NCO-reactive compound.

14. 14. A coating obtainable or produced by applying the one-component or two-component system according to claim 13 to a substrate and curing by heating and / or optionally in the presence of a catalyst.

15. A composite material component comprising a material at least partially bonded to the coating of claim 14.

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