Process for preparation of 2, 2-dialkyl-3-acyloxypropionaldehyde

Abstract

The invention relates to a method for producing aldol esters of formula (I), characterized in that at least one carboxylic acid anhydride of formula (II) and at least one aldol of formula (III) are reacted by heating in the presence of a basic catalyst having a pKa value of the conjugated acid of at least 8, and to the reaction product obtained by said method. The method according to the invention enables the achievement of a reaction product which is light in color, low in odor and has a high content of aldol esters of formula (I), which can be used as a blocking agent for primary amines without a strenuous purification step, in particular without overhead distillation of aldol esters. The blocked amines thus obtained together with isocyanate-containing polymers are storage-stable over a long period of time, cure quickly and process-safely upon contact with moisture, and form high mechanical quality and durable elastomers.

Description

[0001] This application is a divisional application of Chinese patent application 202080034557.0, whose invention name is “Method for preparing 2,2-dialkyl-3-acyloxypropionaldehyde”. Technical Field

[0002] The invention relates to the preparation of aldolester aldehydes and aldol aldehyde imines and to moisture-curing polyurethane compositions comprising them, in particular for use as adhesives, sealants or coatings. Background Art

[0003] 2,2-Dialkyl-3-acyloxypropionaldehyde is a carboxylic acid ester of an aldol from a cross-aldol reaction of aliphatic secondary aldehydes with formaldehyde. It is a universal raw material for the preparation of, for example, fragrances, dyes and polymers. Of particular commercial interest is its use as a blocking agent for primary polyamines. The aldol ester-aldimines obtained in this way are particularly suitable as latent curing agents for polymers containing isocyanate groups. It enables polyurethane compositions with good storage stability, which cure quickly and reliably on contact with moisture and form high-quality and durable elastomers, as described, for example, in EP 1,527,115 or WO 2016 / 005457. The preparation of 2,2-dialkyl-3-acyloxypropionaldehyde has been described many times in the literature. In the known preparation methods, the aldol 2,2-dialkyl-3-hydroxypropanal is used as such or is generated in situ from the starting aldehyde and esterified with a carboxylic acid (in rare cases also with its anhydride or enol ester) to form the aldol ester 2,2-dialkyl-3-acyloxypropanal. The esterification and simultaneous aldolization are usually carried out in the presence of an acidic catalyst (for example sulfuric acid or p-toluenesulfonic acid), and the aldol ester is subsequently separated and purified, in particular by distillation, as described in US Pat. No. 3,251,876, US Pat. No. 3,374,267 or US Pat. No. 3,720,705.

[0004] The disadvantage of the preparation method is that the product yield in practice is relatively low. The reaction product obtained in this way is usually very dark in color, has a pungent smell due to strong odor by-products, and must be purified for further use. In addition, experience shows that the preparation process under acid catalysis (especially the preparation process of short-chain aldol esters) brings thermal process risks, which makes it impossible to operate safely in large-scale production facilities. Not only is the reaction itself like this (especially when operating without solvents or entrainers that limit the reaction temperature), but also the purification of the reaction product after the reaction (especially by overhead distillation purification) is like this. For example, at a temperature in the range of 150°C, a violent exothermic decomposition reaction has already occurred, which cannot be fully suppressed even by the subsequent neutralization of the acidic catalyst. In addition, the strong acidic conditions require preparation in corrosion-resistant facilities. Although the preparation method described in US 4,017,537 without using a catalyst under neutral conditions or the preparation method using pyridine as a catalyst described in DE 19,506,728 does not cause thermal process risks and corrosion problems, it is also unsatisfactory because the reaction time is extremely long and the yield is relatively low. Summary of the invention

[0005] It was therefore an object of the present invention to provide a process for preparing 2,2-dialkyl-3-acyloxypropanal which affords high product yields and can be carried out with good space-time yields without thermal process risks.

[0006] The object is achieved by a process according to claim 1. In this process, carboxylic anhydride and aldol are reacted in the presence of a basic catalyst having a pKa value of at least 8 for the conjugate acid by heating. Such a process using a basic catalyst has not been described to date. It has surprisingly been found that the process according to the invention allows a rapid reaction without thermal process risks and with high yields, and that solvents or entrainers can be omitted. The reaction products obtained are surprisingly light in color and low in odor, and can therefore be used without elaborate purification, in particular without overhead distillation, in particular as blocking agents for primary amines. Due to the lack of corrosive effects on metals, the process according to the invention can be carried out in low-cost standard reactors made of stainless steel. A particularly surprising aspect of the process according to the invention is that the reaction products are stable even when reheated to well above 200° C. in the case of short-chain aldol esters, in particular 2,2-dialkyl-3-acetoxypropionaldehyde, whereas a strong exotherm is observed for the corresponding reaction products from acid-catalyzed processes when heated to above 150° C., which implies a significant thermal process risk.

[0007] The process according to the invention makes it possible to obtain reaction products which are light in color, low in odor and have a high content of 2,2-dialkyl-3-acyloxypropanal, which can be used as blocking agents for primary amines without elaborate purification steps, in particular without overhead distillation of the 2,2-dialkyl-3-acyloxypropanal. The blocked amines or latent curing agents obtained in this way have a low odor, are surprisingly storage stable in combination with isocyanate group-containing polymers, cure rapidly and process-reliably on contact with moisture and form high-quality and durable elastomers.

[0008] Further aspects of the invention are the subject matter of further independent claims. Particularly preferred embodiments of the invention are the subject matter of the dependent claims. DETAILED DESCRIPTION

[0009] The subject of the present invention is a process for preparing aldol esters of the formula (I),

[0010]

[0011] Where R 1 and R 2 represent the same or different alkyl groups having 1 to 4 carbon atoms or together represent an alkylene group having 4 to 6 carbon atoms, and R 3 represents an optionally halogenated hydrocarbon group having 1 to 17 carbon atoms,

[0012] Characterized in that at least one carboxylic anhydride of formula (II)

[0013]

[0014] and at least one aldol of formula (III),

[0015]

[0016] Optionally in the form of its oligomers, it is reacted in the presence of a basic catalyst having a pKa value of at least 8 for the conjugate acid by heating.

[0017] An "aliphatic" aldehyde group or isocyanate group refers to an aldehyde group or isocyanate group that is directly bonded to an aliphatic or cycloaliphatic carbon atom.

[0018] An "aromatic" aldehyde group or isocyanate group refers to an aldehyde group or isocyanate group that is directly bonded to an aromatic carbon atom.

[0019] “Primary amino group” means an amino group which is bonded to only one organic group and carries two hydrogen atoms; “secondary amino group” means an amino group which is bonded to two organic groups (which may also together form part of a ring) and carries one hydrogen atom; and “tertiary amino group” means an amino group which is bonded to three organic groups (two or three of which may also form part of one or more rings) and carries no hydrogen atoms.

[0020] Substance names beginning with "poly", such as polyamine, polyol or polyisocyanate, indicate substances that formally contain two or more of the functional groups appearing in their names per molecule.

[0021] "Molecular weight" refers to the molar mass of a molecule or a molecular group (in grams per mole). "Average molecular weight" refers to the number average molecular weight (M) of a polydisperse mixture of oligomeric or polymeric molecules or molecular groups. n The average molecular weight was determined by gel permeation chromatography (GPC) relative to polystyrene standards.

[0022] Unless otherwise indicated, weight percent (wt%) indicates the mass proportion of an ingredient in a composition based on the entire composition. The terms "mass" and "weight" are used synonymously herein.

[0023] “NCO content” denotes the content of isocyanate groups in % by weight. “Storage-stable” or “storable” means that a substance or composition can be stored in a suitable container at room temperature for a prolonged period of time, generally at least 3 to 6 months and longer, without its application properties or use properties changing during storage to an extent relevant for its use.

[0024] "Room temperature" means a temperature of 23°C.

[0025] All industry standards or specifications mentioned herein refer to the versions in effect at the time of initial filing.

[0026] Preferably, R 1 represents methyl or ethyl, in particular methyl, and R 2 represents methyl, ethyl, n-propyl or n-butyl.

[0027] Particularly preferably, R 1 and R 2 Each represents a methyl group.

[0028] Preferably, R 3 represents an optionally chlorinated hydrocarbon radical having 1 to 11 C atoms.

[0029] Particularly preferably, R 3 represents an alkyl group having 1 to 7 carbon atoms or a phenyl group.

[0030] Most preferably, R3 Represents methyl.

[0031] Preferred groups R 1 , R 2 and R 3 The aldol esters of the formula (I) are particularly readily available and are particularly suitable as blocking agents for primary amines.

[0032] In the small group R 3 In the case of methyl radicals (especially methyl radicals), the process according to the invention is particularly advantageous, since the acid-catalyzed processes known from the prior art lead to strongly colored, odorous and thermally unstable reaction products and are associated with high process risks. 3 The blocked amines of the (especially methyl) aldol esters of the formula (I) are particularly suitable for moisture-curing polyurethane compositions which are to have a particularly low viscosity and / or a particularly high hardness, for example for coatings.

[0033] The basic catalyst preferably has a conjugate acid pKa value of at least 9, in particular at least 10. This results in a particularly rapid reaction.

[0034] Preferably, the basic catalyst is a tertiary amine or an amidine.

[0035] Particularly preferably, the basic catalyst is selected from trimethylamine, dimethylethylamine, methyldiethylamine, triethylamine, diisopropylethylamine, N-methylpyrrolidine, N-methylpiperidine, 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). These compounds are easily available and exhibit good catalytic effects in the process according to the invention.

[0036] Most preferred is triethylamine. It allows a particularly rapid reaction, is inexpensive and volatile and can therefore be easily removed from the reaction mixture by distillation. It is also very suitable as a catalyst for the above-mentioned preparation of the aldol of formula (III).

[0037] The basic catalyst is preferably used in an amount in the range from 0.01 to 10% by weight, in particular from 0.05 to 5% by weight, based on the entire reaction mixture.

[0038] Triethylamine, which is most preferred as catalyst, is preferably used in an amount in the range from 0.1 to 10% by weight, in particular from 0.5 to 5% by weight, based on the entire reaction mixture.

[0039] The process is preferably carried out at a temperature in the range from 80 to 150°C, in particular from 100 to 130°C.

[0040] Preferably, the carboxylic anhydride of the formula (II) is used in a stoichiometric excess relative to the aldol of the formula (III).

[0041] Preferably, the aldol of formula (III) is charged and the carboxylic acid anhydride of formula (II) is added in the presence of a basic catalyst. The carboxylic acid released by the carboxylic acid anhydride, unreacted carboxylic acid anhydride, basic catalyst and optionally volatile by-products and solvents are preferably removed largely or completely from the reaction mixture during or after the reaction, in particular by vacuum distillation.

[0042] Optionally, solvents or entrainers may be used, in particular cyclohexane or toluene or hydrocarbon mixtures (eg petroleum-benzin or hydrogenated light naphtha), in particular those having a boiling point range of 75 to 95° C. or 80 to 100° C.

[0043] The above process is preferably carried out without the use of organic solvents or entrainers.

[0044] The carboxylic anhydride of formula (II) is preferably selected from acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, hexanoic anhydride, 2-ethylhexanoic anhydride, lauric anhydride, benzoic anhydride, chloroacetic anhydride, dichloroacetic anhydride and trichloroacetic anhydride.

[0045] Among them, acetic anhydride, propionic anhydride, hexanoic anhydride, 2-ethylhexanoic anhydride or benzoic anhydride is preferred.

[0046] Most preferred is acetic anhydride.

[0047] The aldols of the formula (III) are optionally used in the form of oligomers, in particular in the form of dimers of the formula (IIIa).

[0048]

[0049] The hydroxyaldehyde of formula (III) or its oligomers are preferably obtained by reacting formaldehyde (optionally in the form of paraformaldehyde or trioxane) with an aldehyde of formula (IV),

[0050]

[0051] Where R 1 and R 2 Has the meanings stated above.

[0052] Formaldehyde is preferably used as formalin or in the form of paraformaldehyde, particularly preferably in the form of paraformaldehyde.

[0053] The aldehyde of formula (IV) is preferably isobutyraldehyde, 2-methylbutyraldehyde, 2-ethylbutyraldehyde, 2-methylpentanal or 2-ethylhexanal. Particularly preferred is isobutyraldehyde.

[0054] The aldehydes of the formula (III) are preferably used as a component of a reaction mixture which is prepared by reacting formaldehyde (optionally in the form of paraformaldehyde or trioxane) with at least one aldehyde of the formula (IV).

[0055]

[0056] The product is obtained by reacting in the presence of a basic catalyst having a conjugate acid pKa value of at least 8.

[0057] Such reaction mixtures containing the aldol of the formula (III) are particularly free of strong acids, in particular halogen-containing acids such as boron trichloride, boron tribromide or hydrochloric acid, and therefore do not form salts with the basic catalyst which could interfere with its activity.

[0058] The reaction of formaldehyde and at least one aldehyde of formula (IV) is a cross aldol reaction. It is preferably carried out in the presence of a basic catalyst having a pKa value of at least 8, preferably at least 9, particularly at least 10 for the conjugate acid. The basic catalyst is preferably the same as the basic catalyst used in the esterification reaction of the carboxylic anhydride of formula (II) with the aldol of formula (III) (i.e. in the method for preparing the aldol ester of formula (I) according to the present invention). Particularly preferred as the basic catalyst for the two reactions is triethylamine.

[0059] The basic catalyst for the aldol reaction is preferably used in an amount in the range from 0.1 to 20% by weight, in particular from 0.5 to 15% by weight, based on the entire reaction mixture of the aldol reaction.

[0060] The aldol reaction is preferably carried out at a temperature in the range of 60 to 90°C.

[0061] The aldehyde of the formula (IV) is preferably used in a stoichiometric excess relative to formaldehyde.

[0062] The formaldehyde is preferably used as formalin or in the form of paraformaldehyde, in particular in the form of paraformaldehyde.

[0063] A solvent may be present in the aldol reaction. Preferably, the aldol reaction is carried out in the absence of an organic solvent.

[0064] After the aldol reaction, the volatile constituents, in particular unreacted aldehyde of the formula (IV), the solvent and optionally a portion of the basic catalyst, are preferably removed from the reaction mixture, in particular by vacuum distillation.

[0065] The method according to the invention is particularly preferably carried out in two steps, wherein

[0066] (i) in a first step (aldol reaction) a basic catalyst and formaldehyde, in particular in the form of paraformaldehyde, are charged, at least one aldehyde of the formula (IV) is then added in a stoichiometric excess relative to the formaldehyde, the aldol of the formula (III) is formed at a temperature in the range from 60 to 90° C., and volatile constituents, in particular the excess aldehyde of the formula (IV) and optionally a portion of the basic catalyst, are then removed from the reaction mixture, and

[0067] (ii) in a second step (esterification), the reaction mixture thus obtained is reacted with a carboxylic anhydride of the formula (II) at a temperature in the range from 100 to 130° C., wherein volatile constituents, in particular the carboxylic acid released by the carboxylic anhydride, unreacted carboxylic anhydride and optionally a basic catalyst, are removed from the reaction mixture during and / or after the reaction, in particular by vacuum distillation.

[0068] Another subject of the present invention is a reaction product obtained by the process according to the invention, in particular a reaction product obtained by the preferred two-step process, characterized in that it contains 60 to 95% by weight, in particular 65 to 90% by weight, particularly preferably 70 to 85% by weight, of the aldol ester of the formula (I) and 5 to 40% by weight, preferably 10 to 35% by weight, in particular 15 to 30% by weight, of other esters, aldehydes and / or acetals which do not correspond to the formula (I).

[0069] The aldol ester of formula (I) contained in the reaction product is preferably selected from 2,2-dimethyl-3-acetoxypropionaldehyde, 2,2-dimethyl-3-propoxypropionaldehyde, 2,2-dimethyl-3-hexanoyloxypropionaldehyde, 2,2-dimethyl-3-(2-ethylhexanoyloxy)propionaldehyde and 2,2-dimethyl-3-benzoyloxypropionaldehyde. Particularly preferred is 2,2-dimethyl-3-acetoxypropionaldehyde.

[0070] In addition to the aldol esters of the formula (I), the reaction products according to the invention preferably also comprise triesters of the formula (V) and / or acetals of the formula (VI).

[0071]

[0072] In formula (V) and (VI), R 1 , R 2 and R 3 Has the meanings stated above.

[0073] The reaction product according to the invention preferably comprises 0.1 to 20% by weight, in particular 0.5 to 15% by weight, particularly preferably 1 to 10% by weight, of triester of the formula (V).

[0074] The reaction product according to the invention preferably comprises 1 to 20% by weight, in particular 2 to 15% by weight, particularly preferably 3 to 10% by weight, of acetal of the formula (VI).

[0075] The reaction product according to the invention has the advantage that it does not contain halides and therefore does not need to be removed by laborious work-up processes.

[0076] The reaction product according to the invention is clear, light in color and has a low odor. It can therefore be used even without further purification. The reaction product is very stable thermally and shows no significant exotherm when heated to up to 200° C. This allows for high process safety in its preparation and processing.

[0077] The reaction product according to the invention can be further purified before use to isolate the aldol ester of formula (I), in particular by overhead distillation. The high thermal stability of the reaction product is particularly advantageous here.

[0078] The reaction product according to the invention is preferably used without further purification.

[0079] The reaction products according to the invention are suitable for a variety of uses, in particular for the preparation of fragrances, dyes or polymers. The reaction products according to the invention are particularly suitable as blocking agents for primary amines.

[0080] The reaction product according to the invention is preferably used to prepare blocked amines. For this purpose, the reaction product is reacted with at least one primary amine. In the reaction, the primary amino groups react with the aldehyde groups in a condensation reaction, releasing water and forming aldimine groups, which are blocked and hydrolytically activated forms of the primary amino groups.

[0081] The blocked amines obtained from the reaction of the reaction product according to the invention with primary amines can advantageously be used as latent curing agents in moisture-curing polyurethane compositions.

[0082] For the reaction with the reaction product according to the invention, preference is given to primary amines which are difunctional with respect to isocyanate groups, i.e. primary amines which, in addition to the primary amino group, also have at least one further primary amino group and / or at least one secondary amino group and / or at least one hydroxyl group. The blocked amines obtained in this way are particularly suitable as latent curing agents for polyurethane compositions. They have particularly advantageous properties with regard to storage stability, processability, curing and mechanical properties.

[0083] Therefore, another subject of the present invention is a blocked amine obtained by reacting the reaction product according to the invention with at least one amine having a primary amino group and at least one reactive group selected from the group consisting of a primary amino group, a secondary amino group and a hydroxyl group. Preferably, the amine contains only secondary amino groups or only hydroxyl groups. Particularly preferably, the amine contains no secondary amino groups.

[0084] In addition to the aldimine from the aldol reaction of the formula (I), the blocked amine obtained therefrom also comprises by-products from the process according to the invention contained in the reaction product used, in particular the triesters of the formula (V) and / or the acetals of the formula (VI) and / or their reaction products with amines.

[0085] Suitable amines for blocking are in particular

[0086] aliphatic primary diamines, such as, in particular, 1,2-ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,3-butylenediamine, 2-methyl-1,2-propylenediamine, 1,3-pentanediamine, 1,5-pentanediamine, 2,2-dimethyl-1,3-propylenediamine, 1,6-hexanediamine, 1,5-diamino-2-methylpentane, 1,7-heptanediamine, 1,8-octanediamine, 2,5-dimethyl-1,6-hexanediamine, 1,9-nonanediamine, 2,2(4),4-trimethyl-1,6-hexanediamine, 1,10-decanediamine, 1,11-undecanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,12-dodecanediamine, 1,2-cyclohexanediamine , 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 4(2)-methyl-1,3-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane, bis(4-amino-3-ethylcyclohexyl)methane, bis(4-amino-3,5-dimethylcyclohexyl)methane, bis(4-amino-3-ethyl-5-methylcyclohexyl)methane, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6 ]decane, 1,3-bis(aminomethyl)benzene, 1,4-bis(aminomethyl)benzene, 3-oxa-1,5-pentanediamine, 3,6-dioxa-octane-1,8-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxadecane-2,9-diamine, 4,9-dioxadodecane-1,12-diamine, 5,8-dioxadodecane-3,10-diamine, 4,7,10-trioxa-tridecane-1,13-diamine, average molecular weight M n α,ω-polyoxypropylene diamines in the range of 170 to 4000 g / mol, in particular Type D-230, D-400, XTJ-582, D-2000, XTJ-578, D-4000 (all from Huntsman), α,ω-polyoxypropylene polyoxyethylene diamine, especially - ED-600, ED-900, ED-2003, HK-511 (all from Huntsman), α,ω-polyoxypropylene polyoxy-1,4-butylene diamine, especially THF-100, THF-140, THF-230, XTJ-533 or XTJ-536 (all from Huntsman), α,ω-polyoxypropylene polyoxy-1,2-butylene diamine, especially Type XTJ-568 or XTJ-569 (both from Huntsman), or α,ω-polyoxy-1,2-butylene diamine, especially XTJ-523 (from Huntsman),

[0087] aliphatic primary triamines, such as, in particular, 1,3,6-triaminohexane, 1,4,8-triaminooctane, 4-aminomethyl-1,8-octanediamine, 5-aminomethyl-1,8-octanediamine, 1,6,11-triaminoundecane, 1,3,5-triaminocyclohexane, 1,3,5-tris-(aminomethyl)cyclohexane, 1,3,5-tris(aminomethyl)benzene, with an average molecular weight M n Tris(ω-polyoxypropyleneamine) starting from trimethylolpropane or glycerol in the range of 330 to 6000 g / mol, in particular T-403, T-3000 or T-5000 (all from Huntsman), or tris(ω-polyoxypropylene-polyoxy-1,2-butyleneamine) starting from trimethylolpropane, especially XTJ-566 (from Huntsman), or

[0088] - primary aromatic diamines such as, in particular, 1,3-phenylenediamine, 1,4-phenylenediamine, 4(2)-methyl-1,3-phenylenediamine (TDA), 3,5-diethyl-2,4(6)-toluenediamine (DETDA) or 4,4'-diaminodiphenylmethane (MDA), or

[0089] aliphatic diamines having primary and secondary amino groups, such as, in particular, N-methyl-1,2-ethylenediamine, N-ethyl-1,2-ethylenediamine, N-butyl-1,2-ethylenediamine, N-hexyl-1,2-ethylenediamine, N-(2-ethylhexyl)-1,2-ethylenediamine, N-cyclohexyl-1,2-ethylenediamine, N-benzyl-1,2-ethylenediamine, 4-aminomethylpiperidine, 3-(4-aminobutyl)piperidine, N-(2-aminoethyl)piperazine, N-(2-aminopropyl)piperazine, N-benzyl-1,2-propylenediamine, N-benzyl-1,3-propylenediamine, N-methyl-1,3-propylenediamine, N-ethyl-1,3-propylenediamine, N-butyl-1,2-ethylenediamine, 3-propylenediamine, N-hexyl-1,3-propylenediamine, N-(2-ethylhexyl)-1,3-propylenediamine, N-dodecyl-1,3-propylenediamine, N-cyclohexyl-1,3-propylenediamine, 3-methylamino-1-pentylamine, 3-ethylamino-1-pentylamine, 3-butylamino-1-pentylamine, 3-hexylamino-1-pentylamine, 3-(2-ethylhexyl)amino-1-pentylamine, 3-dodecylamino-1-pentylamine, 3-cyclohexylamino-1-pentylamine, fatty diamines such as N-coconut oil alkyl-1,3-propylenediamine, N-oleyl-1,3-propylenediamine, N-soybean alkyl-1,3-propylenediamine, N-tallow alkyl-1,3-propylenediamine or N-(C 16-22 Alkyl)-1,3-propylenediamine, available for example from Akzo Nobel under the trade name those obtained, or the products obtained by the Michael addition reaction of aliphatic primary diamines with acrylonitrile, maleic acid diesters or fumaric acid diesters, citraconic acid diesters, (meth)acrylates, (meth)acrylamide or itaconic acid diesters in a molar ratio of 1:1, or

[0090] aliphatic polyamines having two primary and one secondary amino group, such as, in particular, bis(hexamethylene)triamine (BHMT), diethylenetriamine (DETA), dipropylenetriamine (DPTA), N-(2-aminoethyl)-1,3-propanediamine (N3-amine), N3-(3-aminopentyl)-1,3-pentanediamine or N5-(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine, or

[0091] -hydroxyamines such as, in particular, 2-aminoethanol, 2-amino-1-propanol, 1-amino-2-propanol, 3-amino-1-propanol, 4-amino-1-butanol, 4-amino-2-butanol, 2-amino-2-methylpropanol, 5-amino-1-pentanol, 6-amino-1-hexanol, 7-amino-1-heptanol, 8-amino-1-octanol, 10-amino-1-decanol, 12-amino-1-dodecanol or their higher homologues, 4-(2-aminoethyl)-2-hydroxyethylbenzene, 3-aminomethyl-3,5,5-triazine, 4-amino-1-butylene glycol ... Methylcyclohexanol, derivatives of diols (for example diethylene glycol, dipropylene glycol, dibutylene glycol or higher oligomers or polymers of these diols) carrying primary amino groups, in particular 2-(2-aminoethoxy)ethanol, 2-(2-(2-aminoethoxy)ethoxy)ethanol or α-(2-hydroxymethylethyl)-ω-(2-aminomethylethoxy)-poly(oxy(methyl-1,2-ethanediyl), 3-(2-hydroxyethoxy)propylamine, 3-(2-(2-hydroxyethoxy)ethoxy)propylamine or 3-(6-hydroxyhexyloxy)propylamine.

[0092] The amine is particularly selected from 1,6-hexanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 4(2)-methyl-1,3-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, bis(4-aminocyclohexyl)methane, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6 ]Decane, average molecular weight M n α,ω-polyoxypropylene diamines in the range of 170 to 500 g / mol, especially Type D-230 or D-400 (from Huntsman), average molecular weight M n Tris(ω-polyoxypropyleneamine) starting from trimethylolpropane or glycerol, in particular T-403 (from Huntsman), 1,4-phenylenediamine, 3,5-diethyl-2,4(6)-toluenediamine, 2-(2-aminoethoxy)ethanol, 2-(2-(2-aminoethoxy)ethoxy)ethanol, and 3-aminomethyl-3,5,5-trimethylcyclohexanol.

[0093] Among them, preferred are 1,6-hexanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, and an average molecular weight M n α,ω-polyoxypropylene diamine, average molecular weight M in the range of 170 to 300 g / moln Tris(ω-polyoxypropyleneamine) or 2-(2-aminoethoxy)ethanol starting from trimethylolpropane in the range of 330 to 500 g / mol.

[0094] Preferred amines are readily available and enable, in blocked form, moisture-curing polyurethane compositions having good storage stability, good processability, fast curing and high strength and ductility.

[0095] If the blocked amine has hydroxyl or secondary amino groups, these groups can react during storage with the isocyanate groups present.

[0096] The blocked amines according to the invention are preferably prepared by the following process:

[0097] - combining the reaction product according to the invention with an amine to form a reaction mixture, optionally using a solvent, in which the aldehyde groups are present in a stoichiometric amount or in a stoichiometric excess relative to the primary amino groups, and

[0098] - During or after the combination, the condensation water formed in the reaction and the solvent used if necessary are removed from the reaction mixture by suitable methods.

[0099] The condensation water and any solvent used are preferably removed from the heated reaction mixture by applying a vacuum.

[0100] Preferably no solvent is used.

[0101] The reaction is preferably carried out at a temperature in the range of 20 to 120°C, in particular 40 to 100°C.

[0102] A catalyst, particularly an acid catalyst, is optionally used in the reaction.

[0103] The blocked amine according to the invention comprises in particular at least one aldimine of the formula (VII),

[0104]

[0105] in

[0106] m represents 0 or 1, n represents 1, 2 or 3, and (m+n) represents 2 or 3,

[0107] A represents an (m+n)-valent organic group having 2 to 25 carbon atoms, and

[0108] R 1 , R 2 and R 3 Has the meanings stated above.

[0109] Preferably, m is 0 and n is 2 or 3. Such aldimines of the formula (VII) are dialdimines or trimeimines.

[0110] Furthermore, preferably, m is 1 and n is 1. Such aldimines of the formula (VII) are hydroxyaldimines.

[0111] A preferably represents an alkylene group optionally having a cyclic portion or a divalent or trivalent polyoxyalkylene group having 5 to 15 carbon atoms.

[0112] A particularly preferably represents a group selected from the group consisting of 1,6-hexylene, (1,5,5-trimethylcyclohexane-1-yl)methane-1,3- n α,ω-polyoxypropylene, average molecular weight M in the range of 170 to 300 g / mol n Tris(ω-polyoxypropylene), 1,4-phenylene, 3,5-diethyl-2,4(6)-tolylene and 3-oxa-1,5-pentylene starting from trimethylolpropane in the range of 330 to 500 g / mol.

[0113] The aldimine of formula (VII) is particularly preferably selected from N,N'-bis(2,2-dimethyl-3-acetoxypropylene)hexylidene-1,6-diamine, N,N'-bis(2,2-dimethyl-3-acetoxypropylene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine, n N,N'-bis(2,2-dimethyl-3-acetoxypropylene)polyoxypropylene diamine, average molecular weight M in the range of 450 to 880 g / mol n N,N',N"-tris(2,2-dimethyl-3-acetoxypropylene)polyoxypropylenetriamine, N,N'-bis(2,2-dimethyl-3-acetoxypropylene)phenylene-1,4-diamine, N,N'-bis(2,2-dimethyl-3-acetoxypropylene)-3,5-diethyl-toluene-2,4(6)-diamine and N-(2,2-dimethyl-3-acetoxypropylene)-2-(2-aminoethoxy)ethane-1-ol in the range of 730 to 880 g / mol.

[0114] Preferred blocked amines enable moisture-curing polyurethane compositions having good storage stability, good processability, in particular rapid curing and particularly high strength and ductility. In the case of N-(2,2-dimethyl-3-acetoxypropylidene)-2-(2-aminoethoxy)ethane-1-ol, the hydroxyl groups react with the isocyanate groups present during storage.

[0115] Another subject of the present invention is a moisture-curing polyurethane composition comprising

[0116] - at least one polyisocyanate and / or a polymer containing isocyanate groups, and

[0117] - at least one blocked amine obtained by reaction of the reaction product according to the invention as described above.

[0118] The moisture-curing polyurethane composition preferably comprises a blocked amine which contains at least one aldimine of the formula (VII).

[0119] Suitable polyisocyanates are

[0120] - commercially available aromatic, aliphatic or cycloaliphatic diisocyanates, such as, in particular, 4,4′-diphenylmethane diisocyanate (optionally with a proportion of 2,4′- and / or 2,2′-diphenylmethane diisocyanate) (MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 2,4-toluene diisocyanate or a mixture thereof with 2,6-toluene diisocyanate (TDI), 1,4-phenylene diisocyanate (PDI), 1,5-naphthalene diisocyanate (NDI), 1,6-hexane diisocyanate ( HDI), 2,2(4),4-trimethyl-1,6-hexamethylene diisocyanate (TMDI), cyclohexane-1,3- or -1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI), perhydro-2,4'- or -4,4'-diphenylmethane diisocyanate (HMDI), 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane, m- or p-xylylene diisocyanate (XDI), or mixtures thereof,

[0121] - higher-functional derivatives of these diisocyanates, in particular 4,4'-diphenylmethane diisocyanate liquefied by carbodiimidization or uretonimine formation or adduct formation with polyols,

[0122] - mixtures of MDI and MDI homologues (polymeric MDI or PMDI) which are liquid at room temperature,

[0123] - oligomeric diisocyanates, such as, in particular, HDI-biuret, e.g. N100 or N3200 (from Covestro), HDB or HDB-LV (from Vencorex) or 24A-100 (from Asahi Kasei); HDI-isocyanurates, such as N 3300, N 3600 and N 3790BA (all from Covestro), HDT, HDT-LV and HDT-LV2 (from Vencorex), TPA-100 or THA-100 (from Asahi Kasei) or HX (from Tosoh Corp.); HDI-uretdione such as N 3400 (from Covestro); HDI-iminooxadiazinedione such as XP2410 (from Covestro); HDI-allophanates such as VP LS2102 (from Covestro); IPDI-isocyanurate, e.g. in solution Z 4470 (from Covestro) or solid form T1890 / 100 (from Evonik Industries); TDI-oligomers such as IL (from Covestro); or mixed TDI / HDI-based isocyanurates, such as HL (from Covestro); or

[0124] - commercially available triisocyanates, such as, in particular, 4,4',4"-triphenylmethane triisocyanate, RE (from Covestro), or tris(p-isocyanatophenyl)phosphorothioate, can be Obtained from RFE (from Covestro).

[0125] Suitable polymers containing isocyanate groups are in particular the reaction product of at least one polyol with a superstoichiometric amount of at least one diisocyanate. The reaction is preferably carried out at a temperature in the range of 20 to 160° C., in particular 40 to 140° C., optionally in the presence of a suitable catalyst, with exclusion of moisture.

[0126] The NCO / OH ratio is preferably in the range from 1.3 / 1 to 10 / 1. The monomeric diisocyanates remaining in the reaction mixture after the reaction of the OH groups can be removed, in particular by distillation.

[0127] If monomeric diisocyanates are removed from the polymer, the NCO / OH ratio in the reaction is preferably in the range of 3 / 1 to 10 / 1, in particular 4 / 1 to 7 / 1, and the isocyanate group-containing polymer obtained preferably contains at most 0.5% by weight, particularly preferably at most 0.3% by weight, of monomeric diisocyanates after distillation. In this case, the monomeric diisocyanates are removed in particular by short-path vacuum distillation. If monomeric diisocyanates are not removed from the polymer, the NCO / OH ratio in the reaction is preferably in the range of 1.3 / 1 to 2.5 / 1. Such polyether polyurethane polymers contain in particular at most 3% by weight, preferably at most 2% by weight, of monomeric diisocyanates.

[0128] Preferred monomeric diisocyanates are the aromatic, aliphatic or cycloaliphatic diisocyanates already mentioned, in particular MDI, TDI, HDI, HMDI or IPDI, or mixtures thereof.

[0129] Particular preference is given to 4,4'-MDI, TDI or IPDI.

[0130] Suitable polyols are commercially available polyols or mixtures thereof, in particular

[0131] - polyether polyols, in particular polyoxyalkylene diols and / or polyoxyalkylene triols, in particular the polymerization products of ethylene oxide or 1,2-propylene oxide or 1,2- or 2,3-butylene oxide or oxetane or tetrahydrofuran or mixtures thereof, which can be polymerized with the aid of starter molecules having two or three active hydrogen atoms, in particular water, ammonia or compounds having a plurality of OH groups or NH groups, for example 1,2 -ethylene glycol, 1,2- or 1,3-propylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, isomeric dipropylene glycol or tripropylene glycol, isomeric butanediols, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, 1,3- or 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol or aniline, or mixtures of the aforementioned compounds. Also suitable are polyether polyols having polymer particles dispersed therein, in particular those having styrene-acrylonitrile particles (SAN) or polyurea particles or polyhydrazonodicarboxamide particles (PHD).

[0132] Preferred polyether polyols are polyoxypropylene diols or triols, or so-called ethylene oxide-terminated (EO-terminated or EO-terminated) polyoxypropylene diols or triols. The latter are polyoxyethylene-polyoxypropylene mixed polyols which are obtained, in particular, by further alkoxylating polyoxypropylene diols or triols with ethylene oxide after the polypropoxylation reaction has ended, so that they have predominantly primary hydroxyl groups.

[0133] Preferred polyether polyols have an unsaturation of less than 0.02 mEq / g, in particular less than 0.01 mEq / g.

[0134] Polyester polyols (also called oligoesterols), obtainable by known processes, in particular polycondensation of hydroxycarboxylic acids or lactones or of aliphatic and / or aromatic polycarboxylic acids with diols or polyols. Preference is given to polyester diols obtained from the reaction of diols, such as, in particular, 1,2-ethanediol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, glycerol, 1,1,1-trimethylolpropane or mixtures of the above alcohols, with organic dicarboxylic acids or their anhydrides or esters, such as, in particular, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid or mixtures of the above acids, or polyester polyols formed from lactones, such as, in particular, ε-caprolactone. Particular preference is given to polyester polyols obtained from adipic acid or sebacic acid or dodecanedicarboxylic acid and hexanediol or neopentyl glycol.

[0135] Polycarbonate polyols, such as those obtained by reaction of the alcohols described above (for example as used for the synthesis of the polyester polyols) with dialkyl carbonates, diaryl carbonates or phosgene.

[0136] - Block copolymers carrying at least two hydroxyl groups, which have at least two different blocks having a polyether, polyester and / or polycarbonate structure of the abovementioned type, in particular polyether polyester polyols.

[0137] - Polyacrylate polyol or polymethacrylate polyol.

[0138] - polyhydroxy-functional fats or oils, for example natural fats and oils, in particular castor oil; or polyols obtained by chemical modification of natural fats and oils (so-called oleochemical) such as epoxy polyesters or epoxy polyethers obtained by epoxidation of unsaturated oils and subsequent ring opening with carboxylic acids or alcohols, or polyols obtained by hydroformylation and hydrogenation of unsaturated oils; or polyols obtained from natural fats and oils by decomposition processes (for example alcoholysis or ozonolysis) and subsequent chemical bonding (for example by transesterification or dimerization) of the decomposition products obtained or derivatives thereof. Suitable decomposition products of natural fats and oils are in particular fatty acids and fatty alcohols and also fatty acid esters, in particular methyl esters (FAME), which can be derivatized to hydroxy fatty acid esters, for example by hydroformylation and hydrogenation.

[0139] - Polyolefin polyols, also known as oligomeric hydrocarbon alcohols, such as, in particular, polyhydroxy-functional polyolefins, polyisobutylenes, polyisoprenes; polyhydroxy-functional ethylene-propylene copolymers, ethylene-butylene copolymers or ethylene-propylene-diene copolymers, such as those prepared by Kraton Polymers; polyhydroxy-functional diene (in particular 1,3-butadiene) polymers, which can in particular also be prepared by anionic polymerization; copolymers of polyhydroxy-functional dienes (for example 1,3-butadiene or diene mixtures) and vinyl monomers (for example styrene, acrylonitrile, vinyl chloride, vinyl acetate, vinyl alcohol, isobutylene or isoprene), in particular polyhydroxy-functional acrylonitrile / butadiene copolymers, such as, in particular, acrylonitrile / butadiene copolymers terminated by epoxides or amino alcohols and carboxyl groups (for example, those known under the name CTBN or CTBNX or ETBN commercially available from Emerald Performance Materials); or a hydrogenated polyhydroxy-functional diene polymer or copolymer.

[0140] Also particularly suitable are mixtures of the polyols mentioned.

[0141] Preference is given to polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylate polyols or polybutadiene polyols.

[0142] Particular preference is given to polyether polyols, polyester polyols (especially aliphatic polyester polyols) or polycarbonate polyols (especially aliphatic polycarbonate polyols).

[0143] Particularly preferred are polyether polyols, in particular polyoxyalkylene polyols.

[0144] Most preferred are polyoxypropylene diols or triols or ethylene oxide terminated polyoxypropylene diols or triols.

[0145] The average molecular weight M is preferably n Polyols in the range of 400 to 20000 g / mol, preferably 1000 to 15000 g / mol.

[0146] Preference is given to polyols having an OH functionality of 1.6 to 3.

[0147] Preferred are polyols that are liquid at room temperature.

[0148] In the preparation of the isocyanate group-containing polymers, it is also possible to additionally use certain amounts of difunctional or polyfunctional alcohols, in particular 1,2-ethanediol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,3-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, dibromoneopentyl glycol, 1,2-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,2-octanediol, 1,8-Octanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,3- or 1,4-cyclohexanedimethanol, ethoxylated bisphenol A, propoxylated bisphenol A, cyclohexanediol, hydrogenated bisphenol A, dimerized fatty acid alcohols, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol, pentaerythritol, sugar alcohols such as, in particular, xylitol, sorbitol or mannitol, or sugars such as, in particular, sucrose, or alkoxylated derivatives of the abovementioned alcohols or mixtures of the abovementioned alcohols.

[0149] The moisture-curing polyurethane composition preferably comprises at least one polymer containing isocyanate groups.

[0150] The isocyanate group-containing polymer preferably has an average molecular weight M in the range of 1500 to 20000 g / mol, in particular 2000 to 15000 g / mol. n .

[0151] The isocyanate group-containing polymer preferably has an isocyanate group content in the range from 0.5 to 10% by weight, in particular from 1 to 5% by weight.

[0152] The isocyanate group-containing polymers preferably have a low content of monomeric diisocyanates, preferably less than 2% by weight, in particular less than 1% by weight, of monomeric diisocyanates.

[0153] The moisture-curable polyurethane composition preferably further comprises at least one other ingredient selected from fillers, plasticizers, other blocked amines, catalysts and stabilizers.

[0154] Suitable fillers are, in particular, ground or precipitated calcium carbonate, optionally coated with fatty acids, in particular stearates, barite (settled stone), quartz powder, quartz sand, dolomite, wollastonite, calcined kaolin, layered silicates such as mica or talc, zeolites, aluminum hydroxide, magnesium hydroxide, silicon dioxide (including highly dispersed silicon dioxide from pyrogenic processes), cement, gypsum, fly ash, industrially produced carbon black, graphite, metal powders such as aluminum, copper, iron, silver or steel, PVC powder or lightweight fillers such as hollow glass spheres or gas-filled hollow plastic spheres (microspheres), in particular those sold under the trade name Siloxane. (from Akzo Nobel) obtained type.

[0155] Preference is given to calcium carbonate optionally coated with fatty acids, in particular stearates, calcined kaolin, highly disperse silica or industrially produced carbon black.

[0156] Suitable plasticizers are, in particular, carboxylic acid esters, for example phthalates, in particular diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) or di(2-propylheptyl)phthalate (DPHP), hydrogenated phthalates or 1,2-cyclohexanedicarboxylates, in particular hydrogenated diisononyl phthalate or diisononyl-1,2-cyclohexanedicarboxylate (DINCH), terephthalates, in particular bis(2-ethylhexyl)terephthalate (DOTP) or diisononyl terephthalate (DINT), hydrogenated terephthalates or 1,4-cyclohexanedicarboxylates, in particular hydrogenated bis(2-ethylhexyl)terephthalate (DOTP) or diisononyl terephthalate (DINT). Preferred plasticizers are phthalates, hydrogenated phthalates, adipates, in particular dioctyl adipate, azelate, sebacate, benzoate, glycol ethers, glycol esters, plasticizers with a polyether structure, in particular polypropylene oxide mono-, di- or tri-ols with blocked hydroxyl groups, in particular in the form of acetate groups, organic phosphates or sulfonates, polybutene, polyisobutene or plasticizers derived from natural fats or oils, in particular epoxidized soybean oil or linseed oil. Preferred plasticizers are phthalates, hydrogenated phthalates, adipates or plasticizers with a polyether structure.

[0157] Suitable further blocked amines are in particular oxazolidines or aldimines. Preferred further blocked amines are bisoxazolidines of the formula (VIII) or (IX),

[0158]

[0159] in

[0160] D represents a divalent hydrocarbon group having 6 to 15 carbon atoms, in particular 1,6-hexylene or (1,5,5-trimethylcyclohexane-1-yl)methane-1,3 or 4(2)-methyl-1,3-phenylene, and

[0161] Q is a monovalent organic radical having 3 to 26 carbon atoms, in particular 2-propyl, 3-heptyl, phenyl or substituted phenyl, in particular phenyl substituted in the para position by optionally branched decylphenyl, undecylphenyl, dodecylphenyl, tridecylphenyl or tetradecylphenyl.

[0162] Also preferred as further blocked amines are those of the formula wherein L represents an alkyl, cycloalkyl or aralkyl group having 1 to 8 carbon atoms, in particular a methyl, ethyl or n-butyl group, and Q has the meaning given above.

[0163] Also preferred as further blocked amines are those of the formula An aldimine wherein y represents 2 or 3, G represents an organic group having 2 to 23 carbon atoms, and B represents an organic group having 6 to 30 carbon atoms.

[0164] G preferably represents an alkylene group optionally having a cyclic portion or a divalent or trivalent polyoxyalkylene group having 5 to 15 carbon atoms, in particular 1,6-hexylene, (1,5,5-trimethylcyclohexane-1-yl)methane-1,3- or a 1,5,5-trimethylcyclohexane-1-yl group having an average molecular weight of 1. n α,ω-polyoxypropylene or average molecular weight M in the range of 170 to 300 g / mol n Tris(ω-polyoxypropylene) starting from trimethylolpropane in the range of 330 to 500 g / mol. B preferably represents an organic radical having 7 to 22 carbon atoms, in particular 2,2-dimethyl-3-(N-morpholino)propylene, 2,2-dimethyl-3-lauroyloxypropylene, benzylidene or substituted benzylidene, in particular 4-decylbenzylidene, 4-undecylbenzylidene, 4-dodecylbenzylidene, 4-tridecylbenzylidene or 4-tetradecylbenzylidene, the 4-alkyl radical optionally being present in branched form.

[0165] The moisture-curing polyurethane composition particularly preferably comprises at least one bisoxazolidine of the formula (VIII) in which D represents 1,6-hexamethylene. Such compositions enable particularly high strength and high ductility to be achieved.

[0166] Suitable catalysts are catalysts for accelerating the reaction of isocyanate groups, in particular organotin(IV) compounds such as, in particular, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dibutyltin diacetylacetonate, dimethyltin dilaurate, dioctyltin diacetate, dioctyltin dilaurate or dioctyltin diacetylacetonate, complexes of bismuth(III) or zirconium(IV), in particular with a ligand selected from the group consisting of alkoxides, carboxylates, 1,3-diketonates, hydroxyquinolinates, 1,3-ketoesters and 1,3-ketoamidates, or compounds containing tertiary amino groups such as, in particular, 2,2′-dimorpholinodiethyl ether (DMDEE).

[0167] Suitable catalysts are also catalysts for the hydrolysis of aldimine groups, in particular organic acids, in particular carboxylic acids such as 2-ethylhexanoic acid, lauric acid, stearic acid, isostearic acid, oleic acid, neodecanoic acid, benzoic acid, salicylic acid or 2-nitrobenzoic acid, organic carboxylic acid anhydrides such as phthalic anhydride, hexahydrophthalic anhydride or methylhexahydrophthalic anhydride, silyl esters of carboxylic acids, organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid or 4-dodecylbenzenesulfonic acid, sulfonic esters, other organic acids or inorganic acids, or mixtures of the above acids and esters. Particularly preferred are carboxylic acids, in particular aromatic carboxylic acids such as benzoic acid, 2-nitrobenzoic acid, in particular salicylic acid.

[0168] In particular, combinations of different catalysts are also suitable.

[0169] Suitable stabilizers are, in particular, stabilizers against oxidation, heat, light or UV radiation, in particular titanium dioxide, iron oxide, zinc oxide, benzophenone, benzotriazole, compounds having a 2,6-di-tert-butylphenol group, for example those sold under the trade name Compounds with 2,2,6,6-tetramethylpiperidinyl groups, so-called HALS (hindered amine light stabilizers), are known, for example, under the trade name (from BASF), or phosphorus-containing compounds, for example under the trade name (from BASF) those known.

[0170] The moisture-curing polyurethane composition may contain other additives, in particular

[0171] - inorganic or organic pigments, in particular titanium dioxide, chromium oxide or iron oxide;

[0172] - fibers, in particular glass fibers, carbon fibers, metal fibers, ceramic fibers, plastic fibers, for example polyamide fibers or polyethylene fibers, or natural fibers, for example wool, cellulose, or sisal;

[0173] - nanofillers such as graphene or carbon nanotubes;

[0174] -dye;

[0175] - drying agents, in particular molecular sieves, calcium oxide, highly reactive isocyanates such as p-toluenesulfonyl isocyanate, monooxazolidines such as 2 (from Incorez) or orthoformate;

[0176] - adhesion promoters, in particular organoalkoxysilanes, in particular epoxysilanes such as in particular 3-glycidyloxypropyltrimethoxysilane or 3-glycidyloxypropyltriethoxysilane, (meth)acryloylsilanes, anhydridesilanes, carbamatesilanes, alkylsilanes or iminosilanes, or oligomeric forms of these silanes, or titanates;

[0177] - other catalysts which accelerate the reaction of isocyanate groups;

[0178] - rheology modifiers, in particular thickeners, in particular layered silicates such as bentonites, castor oil derivatives, hydrogenated castor oil, polyamides, polyamide waxes, polyurethanes, urea compounds, pyrogenic silicas, cellulose ethers or hydrophobically modified polyoxyethylenes;

[0179] - solvents, in particular acetone, methyl acetate, tert-butyl acetate, 1-methoxy-2-propyl acetate, ethyl-3-ethoxypropionate, diisopropyl ether, diethylene glycol diethyl ether, ethylene glycol diethyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-2-ethylhexyl ether, acetals such as propionate, butyral, 2-ethylhexane acetal, dioxolane, glycerol formal or 2,5,7,10-tetraoxaundecane (TOU), toluene, xylene, heptane, octane, naphtha, white spirit, petroleum ether or gasoline, in particular Solvesso TM -type (from Exxon), and propylene carbonate, dimethyl carbonate, butyrolactone, N-methylpyrrolidone, N-ethylpyrrolidone, p-chlorobenzotrifluoride or benzotrifluoride;

[0180] - natural resins, fats or oils such as rosin, shellac, linseed oil, castor oil or soybean oil;

[0181] - non-reactive polymers, in particular homopolymers or copolymers of unsaturated monomers, in particular selected from ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or alkyl (meth)acrylates, in particular polyethylene (PE), polypropylene (PP), polyisobutylene, ethylene-vinyl acetate copolymers (EVA) or atactic poly-α-olefins (APAO);

[0182] - flame-retardant substances, in particular the fillers aluminum hydroxide or magnesium hydroxide described above, and in particular organic phosphates, such as in particular triethyl phosphate, tricresyl phosphate, triphenyl phosphate, diphenylcresyl phosphate, isodecyldiphenyl phosphate, tris(1,3-dichloro-2-propyl)phosphate, tris(2-chloroethyl)phosphate, tris(2-ethylhexyl)phosphate, tris(chloroisopropyl)phosphate, tris(chloropropyl)phosphate, isopropylated triphenyl phosphate, mono-, di- and tri(isopropylphenyl)phosphates of varying degrees of isopropylation, resorcinol-bis(diphenyl phosphate), bisphenol-A-bis(diphenyl phosphate) or ammonium polyphosphate;

[0183] - Additives, in particular wetting agents, leveling agents, defoamers, deaerators or biocides;

[0184] or other materials commonly used in moisture-curing polyurethane compositions.

[0185] It may be desirable to chemically or physically dry certain materials prior to incorporation into the composition.

[0186] The moisture-curing polyurethane composition is prepared in particular under the exclusion of moisture and stored in a moisture-tight container at ambient temperature. Suitable moisture-tight containers are made in particular of optionally coated metal and / or plastic and are in particular barrels, containers, bottles, buckets, barrels, cans, bags, hose bags, magazines or tubes.

[0187] The moisture-curing polyurethane composition may be present in the form of a one-component composition or in the form of a multi-component (especially two-component) composition.

[0188] "One-component" refers to a composition in which all ingredients of the composition are present in the same container and are inherently storage stable.

[0189] “Two-component” refers to a composition whose constituents are present in two different components which are stored in separate containers and are not mixed with one another until immediately before or during application of the composition.

[0190] The moisture-curable polyurethane composition is preferably a one-component composition and is generally storage-stable for a period of several months to a year or more in suitable packaging and storage containers.

[0191] When the moisture-curing polyurethane composition is applied, the curing process begins. The result is a cured composition.

[0192] In the case of a one-component composition, the composition is applied in its own form and then begins to cure under the action of moisture or water. To accelerate curing, an accelerator component comprising water and optionally a catalyst and / or a curing agent can be admixed to the composition during application or the composition can be contacted with the accelerator component after application.

[0193] During curing, the isocyanate groups react with the hydrolyzed aldimine groups and optionally other blocked amino groups (simultaneously or subsequently thereto) under the influence of moisture to form urea groups. These and any other reactions of the isocyanate groups that lead to the curing of the composition are referred to as crosslinking.

[0194] The moisture required for the curing of the moisture-curing polyurethane composition preferably enters the composition from the air (air moisture) by diffusion. A solid layer (skin) of the cured composition is formed on the surface of the composition in contact with the air. Curing is carried out from the outside to the inside along the diffusion direction, wherein the skin becomes thicker and thicker and eventually contains all the applied composition. Moisture can also enter the composition additionally or completely from one or more substrates on which the composition is applied and / or originate from the accelerator component, which is mixed into the composition at the time of application or is contacted with the mixture after application (e.g., by smearing or spraying).

[0195] The moisture-curing polyurethane composition is preferably applied at ambient temperature, in particular about -10 to 50°C, preferably -5 to 45°C, in particular 0 to 40°C.

[0196] Curing of the moisture-cure polyurethane composition is preferably carried out at ambient temperature.

[0197] Preferably, the moisture-curing polyurethane compositions are used as adhesives or sealants or coatings, in particular in the construction industry and the manufacturing industry or in automobile construction.

[0198] Preferably, they are used as elastic adhesives and / or sealants, in particular for floor panel bonding, assembly, installation part bonding, module bonding, window bonding, seam sealing, body sealing, gap sealing or cavity sealing, or for elastic bonding in automobile construction, for example, in particular for adhering parts such as plastic covers, trims, flanges, bumpers, cockpits or other installation parts to painted bodies of vehicles, or for bonding windows in bodies, the vehicles being in particular cars, trucks, buses, rail vehicles or ships.

[0199] Preference is also given to use as an elastic coating for protecting floors or walls, in particular as a so-called liquid applied membrane for sealing roofs (in particular flat roofs or slightly sloping roofs or roof gardens), or for waterproofing in building interiors (for example under tiles or ceramic slabs in sinks or kitchens or on balconies), or as a gap sealant or as a sealant or coating for repair purposes, for example for unsealed roof membranes or other elastic seals. BRIEF DESCRIPTION OF THE DRAWINGS

[0200] Figure 1 and Figure 2 The DSC diagrams of the reaction products in Examples 1 and 2 are respectively.

[0201] Example

[0202] Examples are described below which explain the invention in more detail. The invention is of course not limited to the examples described.

[0203] "Standard climate" (NK) means a temperature of 23±1° C. and a relative air humidity of 50±5%.

[0204] If not stated otherwise, the chemicals used were from Sigma-Aldrich Chemie GmbH.

[0205] Measurement method description:

[0206] Gas chromatography (GC) was measured in the temperature range of 60 to 320°C with a heating rate of 15°C / min and a residence time of 10 min at 320°C. The injector temperature was 250°C. A Zebron ZB-5 column (L=30m, ID=0.25mm, dj=0.5μm) was used and the gas flow rate was 1.5ml / min. The inspection was carried out by flame ionization (FID). Mass spectrometry (EI + ) GC-peaks were assigned to chemical structures. Infrared spectra (FT-IR) were measured in undiluted thin films on a FT-IR instrument Bruker Alpha Eco-ATR. Absorption bands are expressed in wavenumbers (cm -1 )express.

[0207] The temperature range was 10 to 400 °C with a heating rate of 4 K / min using a Mettler Toledo DSC 3+700 apparatus by using an adiabatic pressure crucible M20 (from Switzerland). DSC analysis (Differential Scanning Calorimetry) (first run) was performed on the samples.

[0208] The amine value (including blocked amino groups) was determined by titration (using 0.1 N HClO4 in acetic acid and crystal violet as indicator).

[0209] Preparation of aldol esters of formula (I):

[0210] Embodiment 1:

[0211] Preparation of a reaction product comprising 2,2-dimethyl-3-acetoxypropanal according to the invention in the presence of triethylamine

[0212] Step 1 (Aldol reaction):

[0213] 297 kg of triethylamine (from BASF), 587 kg of paraformaldehyde (from Tennants Fine Chemicals) and 282 kg of deionized water were pre-charged and mixed in a V4A steel reactor equipped with a metering system, a stirring system, a heating system and a cooling system and a distillation column with a condenser placed under a nitrogen atmosphere. The mixture was heated to 60 ° C with stirring and reflux. Then 1523 kg of isobutylaldehyde (from BASF) was metered in over 3 hours and the reaction mixture was kept at 65 to 75 ° C with reflux. After continuing to reflux for 30 minutes, no more heat was observed. Then it was converted to distillation, the internal pressure was slowly reduced and the volatile components were first distilled at 85 ° C / 250 mbar and then at 100 ° C / 50 mbar. 705 kg of distillate (according to gas chromatography, unreacted isobutylaldehyde, water and a large amount of triethylamine) were collected. 1924 kg of reaction mixture remained in the reactor, which, according to gas chromatography, comprised about 88% by weight of 2,2-dimethyl-3-hydroxypropanal (retention time 3.2 min) and about 4% by weight of triethylamine (retention time 2.2 min).

[0214] Step 2 (esterification):

[0215] The reactor was then brought to standard pressure with the aid of nitrogen, reflux was set and the internal temperature was heated to 110°C. The internal pressure was then reduced to 250mbar and 2076kg of acetic anhydride (from BP Chemicals) was added and mixed within 1 hour. The volatile components were then removed from the reaction mixture. To this end, the reactor was set to fractionation (80% reflux) and distilled at a tower top temperature of about 78°C. Once the tower top temperature reached 80°C, the internal pressure of the reactor was slowly reduced and distilled for a sufficiently long time until the tower top temperature reached 80°C again. If the tower top temperature exceeded 80°C at an internal pressure of 30mbar, the distillation was terminated or the removal of volatile components from the reaction mixture was terminated. A total of 2134kg of distillate (according to gas chromatography, it was unreacted acetic anhydride, acetic acid, triethylamine and 2,2-dimethyl-3-acetoxypropionaldehyde) was collected. The reaction product was then cooled and placed under a nitrogen atmosphere.

[0216] 1851 kg of a clear, light yellow liquid with a slight fruity odor was obtained. According to gas chromatography, the reaction product contained about 78% by weight of 2,2-dimethyl-3-acetoxypropanal (retention time 4.8 min), about 5.7% by weight of triester of formula (V) (retention time 10.9 min) and about 6.3% by weight of acetal of formula (VI) (retention times 6.4 min and 6.6 min). It is referred to below as the "reaction product from Example 1".

[0217] FT-IR: 2973, 2938, 2877, 2818, 2716, 1728, 1473, 1374, 1228, 1160, 1118, 1040, 892, 775.

[0218] Record the DSC of the reaction product and show Figure 1 A weak exotherm of 20 kJ / kg was determined in the range of 105 to 155°C.

[0219] Purification of the reaction product by overhead distillation: (as a comparison)

[0220] 500 g of the reaction product obtained from Example 1 were vacuum distilled in a round-bottom flask with a distillation column at 120 to 130° C. At a top temperature of 84 to 87° C., 30 mbar and 60% reflux, 370.4 g of distillate (=2,2-dimethyl-3-acetoxypropanal from Example 1 distilled overhead) were obtained, which contained about 94% by weight of 2,2-dimethyl-3-acetoxypropanal according to gas chromatography.

[0221] At a top temperature of 76 to 80° C., 30 mbar and 80% reflux, 73.8 g of a first fraction (=first fraction) were collected. According to gas chromatography, it contained about 56% by weight of 2,2-dimethyl-3-acetoxypropanal, about 17% by weight of acetic acid and about 18% by weight of triethylamine. 55.8 g of a residue remained, whose content of 2,2-dimethyl-3-acetoxypropanal was 0.8% by weight.

[0222] Example 2: (Comparison)

[0223] Preparation of 2,2-dimethyl-3-acetoxypropanal in the presence of acid

[0224] In a round-bottom flask with a distillation column and a water separator, 100 g of cyclohexane, 144.0 g of paraformaldehyde, 403.7 g of acetic acid and 6.3 g of p-toluenesulfonic acid were pre-charged and mixed under a nitrogen atmosphere. The mixture was heated to 60° C. with sufficient stirring and reflux and 346.4 g of isobutylaldehyde was slowly added so that the internal temperature did not exceed 75° C. Then the reflux was switched to water separation and slowly heated to an internal temperature of 100° C. When the internal temperature reached 100° C., the internal pressure was slowly reduced, wherein it was ensured that the internal temperature remained at about 100° C. 81 g of water was separated at an internal pressure of 600 mbar. Then the water separation was switched to distillation, and the internal pressure was further reduced so that the internal temperature remained at about 100° C. Most of the excess acetic acid was removed at an internal pressure of 30 mbar and a top temperature of 67° C. The reaction product was cooled and placed under a nitrogen atmosphere. According to gas chromatography, the collected distillate consisted mainly of cyclohexane, some water, isobutylaldehyde and acetic acid.

[0225] 576 g of a dark liquid with a pungent odor were obtained. According to gas chromatography, the reaction product contained about 61.7% by weight of 2,2-dimethyl-3-acetoxypropanal (retention time 4.8 min).

[0226] The DSC recorded for the reaction product from Example 2 showed Figure 2 A strong exotherm of 530 kJ / kg was determined in the range of 100 to 400°C.

[0227] Preparation of blocked amines:

[0228] Aldimine A1: (from the reaction product according to the invention)

[0229] N,N'-Bis(2,2-dimethyl-3-acetoxypropylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine

[0230] 373.0 g of the reaction product from Example 1 containing about 78% by weight of 2,2-dimethyl-3-acetoxypropanal were placed in a round-bottom flask under a nitrogen atmosphere. Then 170.3 g (1 mol) of 3-aminomethyl-3,5,5-trimethylcyclohexylamine ( IPD from Evonik) and then freed from volatile constituents at 80° C. and 10 mbar vacuum. 497 g of a clear, pale yellow, low-viscosity liquid with a slight fruity odor were obtained with an amine number of 223 mg KOH / g, corresponding to a calculated aldimine equivalent of 252 g / eq.

[0231] Aldimine R1: (Comparison, from purified reaction product)

[0232] N,N'-Bis(2,2-dimethyl-3-acetoxypropylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine

[0233] Under nitrogen atmosphere, 293 g of 2,2-dimethyl-3-acetoxypropanal from Example 1 was initially placed in a round-bottom flask by overhead distillation. Then, 170.3 g (1 mol) of 3-aminomethyl-3,5,5-trimethylcyclohexylamine ( IPD from Evonik) and then freed from volatile constituents at 80° C. and 10 mbar vacuum. 418 g of a clear, almost colorless, low-viscosity liquid with a slight fruity odor were obtained with an amine number of 262 mg KOH / g, corresponding to a calculated aldimine equivalent of 214 g / eq.

[0234] Moisture-curing polyurethane composition:

[0235] Compositions Z1 and Z2

[0236] For each composition, the following ingredients were mixed in a centrifugal mixer with the exclusion of water until a macroscopically homogeneous liquid was formed:

[0237] 213.7 g of polyoxypropylene glycol with an OH value of 56 mg KOH / g and toluene diisocyanate ( T 80P from Covestro), a polymer containing isocyanate groups with an NCO content of 3.7% by weight, 61.3 g of a crosslinker ( L67MPA / X from Covestro), 73 g of plasticizer, 149 g of solvent, 19 g of thickener, 417 g of inorganic filler and 0.5 g of salicylic acid. 67.7 g of aldimine A1 and 57.5 g of aldimine R1 were also added to composition Z1 and Z2, respectively.

[0238] Each composition was stored in a sealed metal container with the exclusion of moisture and then tested as follows:

[0239] The viscosity is determined using a Rotothinner at 20°C. "Fresh" means the viscosity measured 24 hours after preparation of the composition. "4w 40°C" or "8w 40°C" means the viscosity after storage in a closed container at 40°C for 4 or 8 weeks.

[0240] The cure speed ("BK drying time") is determined in accordance with ASTM D5895 using a Beck-Koller drying time recorder in standard climate. The results of Stage 2 correspond to the skinning time (tack-free time) of the composition.

[0241] The degree of curing is determined by applying the composition in the form of a cylinder with a diameter of 40 mm and a height of 4 mm, leaving it to stand at standard climate (NK) or 5°C / 80% relative humidity, cutting it after 24h or 48h and measuring the thickness of the cured layer formed on the surface of the composition. Depending on the curing time and climate conditions, the results are expressed as "24h NK" or "48h NK" or "48h5°C".

[0242] For each composition, a two-layer cured film was produced to determine the mechanical properties. For this purpose, a first layer with a thickness of 800 μm was applied with a doctor blade and stored for 24 h in a standard climate, and then a second layer with a thickness of 400 μm was applied with a doctor blade at an angle of 90° to the first layer. The two-layer film was stored for a further 24 h in a standard climate and then for 24 h in a circulating air oven at 60° C. After a further 24 h in a standard climate, strip specimens with a length of 100 mm and a width of 25 mm were punched out of the film and subjected to DIN EN 53504 at a tensile speed of 180 mm / min and a track length of 60 mm. Determine the tensile strength and elongation at break.

[0243] The appearance was determined visually on films prepared for determination of mechanical properties.

[0244] The odour was determined by sniffing at a distance of about 100 mm on a freshly applied flat composition with a diameter of about 150 mm.

[0245]

[0246]

[0247] Table 1: Properties of compositions Z1 and Z2.

[0248] As can be seen from Table 1, the reaction product according to the invention from Example 1 is particularly suitable as such (i.e. without further purification by overhead distillation) for preparing aldimines A1 which are used as blocked amines or as latent hardeners in one-component moisture-curing compositions. Surprisingly, composition Z1 sometimes even exhibits better properties than composition Z2, which comprises aldimine R1 derived from 2,2-dimethyl-3-acetoxypropanal purified by overhead distillation. In particular, composition Z1 exhibits particularly low viscosity (even after storage) and particularly high elongation and otherwise comparable properties.

[0249] The compositions Z1 and Z2 are particularly suitable as coatings or coverings, in particular as so-called liquid applied membranes for sealing roofs, bridges, platforms and the like.

Claims

1. A method for preparing an aldol ester of formula (I), Where R 1 and R 2 represent the same or different alkyl groups having 1 to 4 carbon atoms or together represent an alkylene group having 4 to 6 carbon atoms, and R 3 represents an optionally halogenated hydrocarbon group having 1 to 17 carbon atoms, It is characterized in that At least one carboxylic anhydride of formula (II) and at least one aldol of formula (III), Optionally in the form of its oligomers, the reaction is carried out by heating in the presence of a basic catalyst having a pKa value of at least 8 for the conjugate acid.

2. The method according to claim 1, characterized in that: R 1 and R 2 Each represents a methyl group.

3. The method according to any one of claims 1 to 2, characterized in that R 3 represents an alkyl radical having 1 to 7 carbon atoms or represents a phenyl radical, in particular a methyl radical.

4. The method according to any one of claims 1 to 3, characterized in that The pKa value of the conjugate acid of the basic catalyst is at least 9, in particular at least 10.

5. The method according to any one of claims 1 to 4, characterized in that The basic catalyst is triethylamine.

6. The method according to any one of claims 1 to 5, characterized in that The process is carried out at a temperature in the range of 80 to 150°C, in particular 100 to 130°C.

7. The method according to any one of claims 1 to 6, characterized in that The process is carried out without the use of organic solvents or entrainers.

8. The method according to any one of claims 1 to 7, characterized in that The hydroxyaldehyde of formula (III) is used as a component of a reaction mixture which is reacted by reacting formaldehyde with at least one aldehyde of formula (IV) The product is obtained by reacting in the presence of a basic catalyst having a pKa value of at least 8 for the conjugate acid, wherein the formaldehyde is optionally in the form of paraformaldehyde or trioxane.

9. The method according to any one of claims 1 to 8, characterized in that It is carried out in two steps, (i) in a first step, a basic catalyst and formaldehyde, in particular in the form of paraformaldehyde, are charged and then at least one aldehyde of the formula (IV) is added in a stoichiometric excess relative to the formaldehyde. The aldol of formula (III) is formed at a temperature in the range of 60 to 90° C., and the volatile components are then removed from the reaction mixture, and (ii) In a second step, the reaction mixture thus obtained is reacted with a carboxylic anhydride of the formula (II) at a temperature in the range from 100 to 130° C., wherein volatile constituents are removed from the reaction mixture during and / or after the reaction.

10. The reaction product obtained by the method according to any one of claims 1 to 9, characterized in that They comprise 60 to 95% by weight of aldol esters of the formula (I) and 5 to 40% by weight of other esters, aldehydes and / or acetals which do not correspond to the formula (I).

11. The reaction product according to claim 10, characterized in that It comprises a triester of formula (V) and / or an acetal of formula (VI), In particular, 0.1 to 20% by weight of triesters of the formula (V) and 1 to 20% by weight of acetals of the formula (VI).

12. Blocked amine obtained by reaction of the reaction product according to claim 10 with at least one amine having a primary amino group and further at least one reactive group selected from the group consisting of a primary amino group, a secondary amino group and a hydroxyl group.

13. The blocked amine according to claim 12, characterized in that The amine is selected from 1,6-hexanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 4(2)-methyl-1,3-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, bis(4-aminocyclohexyl)methane, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6 ]Decane, average molecular weight M n α,ω-polyoxypropylene diamine, average molecular weight M in the range of 170 to 500 g / mol n Tri(ω-polyoxypropyleneamine) starting from trimethylolpropane or glycerol, 1,4-phenylenediamine, 3,5-diethyl-2,4(6)-toluenediamine, 2-(2-aminoethoxy)ethanol, 2-(2-(2-aminoethoxy)ethoxy)ethanol and 3-aminomethyl-3,5,5-trimethylcyclohexanol in the range of 330 to 500 g / mol.

14. Polyurethane-composition comprising - at least one polyisocyanate and / or polymer containing isocyanate groups, and - at least one blocked amine according to any one of claims 12 to 13.

15. Use of the polyurethane composition according to claim 14 as an adhesive or a sealant or a coating.

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