Accelerators for epoxy resins

Description

Technical area

[0001] The invention relates to amines and their use for curing epoxy resins. State of the art

[0002] Epoxy resin compositions are used in a variety of ways, including as adhesives or coatings in the construction and manufacturing industries. It is advantageous if the compositions cure quickly and reliably, thus becoming mechanically resilient as soon as possible after application. Accelerators are often used to accelerate curing, particularly in cold-curing systems. Phenols are known to be particularly effective accelerators. Many of the well-known accelerators, such as nonylphenol and tert-butylphenol, are rarely used today because they are toxic in themselves, are not incorporated into the polymer network during curing, and can therefore lead to emissions, contamination, or discoloration. The most effective accelerator for cold-curing systems is 2,4,6-tris(dimethylaminomethyl)phenol. However, it emits a strong, unpleasant amine odor.Other well-known accelerators are acids, especially salicylic acid. While they produce little odor, they cause a significant increase in viscosity, and their accelerating effect is often insufficient.

[0003] Accelerators that are incorporated into the polymer network during curing are particularly advantageous. Amine hardeners that also act as accelerators and are incorporated into the polymer network during curing are known from the state of the art, for example, 3-dimethylaminopropylamine (DMAPA), 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA), or 2,4,6-tris((2-dimethylaminopropyl)aminomethyl)phenol. However, all three cause significant blushing effects at cool ambient temperatures and when applied over large areas, and their accelerating effect can still be improved for many applications.

[0004] Alkylated amines are known as hardeners for epoxy resin coatings, for example, from EP 3,180,383 or EP 3,344,677. They exhibit reliable curing at ambient temperatures and little tendency toward blushing when applied over large areas. However, the curing rates achieved with them still have room for improvement.

[0005] WO 2015 / 124792 A1 also deals with blushing effects in the context of amine hardeners for epoxy resins. Description of the invention

[0006] The object of the present invention is therefore to provide a low-odor accelerator for curing epoxy resins, which enables particularly rapid curing, does not cause an increase in viscosity and is incorporated into the cured polymer network.

[0007] Surprisingly, an amine of formula (I) as described in claim 1 solves this problem. The amine of formula (I) can be prepared in a simple process by reductive alkylation of a dimethylamine with a benzonitrile bearing a formyl or acetyl group and hydrogen. It is low-odor, low-viscosity, and exhibits excellent properties as a hardener and accelerator. It enables surprisingly rapid and trouble-free curing and high final hardness, producing beautiful, defect-free surfaces with high gloss even when applied over large areas and at cold temperatures.

[0008] The amine of formula (I) is suitable as a hardener, co-hardener, and / or incorporable accelerator for epoxy resin products, such as, in particular, coatings, adhesives, potting compounds, molded articles, or matrix resins for composite materials. Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims. Ways to implement the invention

[0009] The invention relates to the use of an amine of formula (I) for curing epoxy resins, where n is 0 or 1 or 2, R is H or methyl and A is an alkylene radical having 2 to 6 C atoms.

[0010] Substance names beginning with "poly," such as polyamine or polyepoxide, refer to substances that formally contain two or more of the functional groups mentioned in their name per molecule.

[0011] A "primary amino group" is an amino group that is bonded to a single organic residue and carries two hydrogen atoms; a "secondary amino group" is an amino group that is bonded to two organic residues, which may also be part of a ring, and carries one hydrogen atom; and a "tertiary amino group" is an amino group that is bonded to three organic residues, which may also be part of one or more rings in twos or threes, and does not carry a hydrogen atom.

[0012] The hydrogen atoms of primary and secondary amine groups are called "amine hydrogen".

[0013] The "amine hydrogen equivalent weight" is the mass of an amine or amine-containing compound containing one molar equivalent of amine hydrogen. It is expressed in the unit "g / eq."

[0014] The "epoxide equivalent weight" is the mass of an epoxy-containing compound or composition that contains one molar equivalent of epoxy groups. It is expressed in the unit "g / eq."

[0015] A "thinner" is a substance that is soluble in an epoxy resin and reduces its viscosity, but which is not chemically bound into the epoxy resin polymer during curing.

[0016] "Molecular weight" refers to the molar mass (in grams per mole) of a molecule. "Mean molecular weight" refers to the number average M n of a polydisperse mixture of oligomeric or polymeric molecules, which is usually determined by gel permeation chromatography (GPC) against polystyrene as a standard.

[0017] Pot life is the maximum period of time from the mixing of the components and the application of an epoxy resin composition during which the mixed composition is in a sufficiently flowable state and can wet the substrate surfaces well.

[0018] The term "gel time" refers to the time from the mixing of the components of an epoxy resin composition until they gel.

[0019] “Room temperature” is defined as 23 °C.

[0020] All industry standards and norms mentioned in this document refer to the versions valid at the time of filing the initial application, unless otherwise stated.

[0021] Percentages by weight (% by weight) refer to the mass fraction of a component of a composition relative to the total composition, unless otherwise stated. The terms "mass" and "weight" are used synonymously in this document.

[0022] Preferably, R is H. These amines of formula (I) enable particularly rapid curing.

[0023] Preferably, A represents 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene or 1,5-pentylene.

[0024] A particularly preferably represents 1,2-ethylene or 1,3-propylene, in particular 1,3-propylene.

[0025] Preferably, n is 0 or 1. More preferably, n is 1.

[0026] Preferably, the amine of formula (I) is selected from the group consisting of N,N-dimethyl-1,3-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,3-bis(aminomethyl)benzene, N-(3-dimethylaminopropyl)-1,3-bis(aminomethyl)benzene, N,N-dimethyl-1,4-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,4-bis(aminomethyl)benzene, N-(3-dimethylaminopropyl)-1,4-bis(aminomethyl)benzene, N,N-dimethyl-1,2-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,2-bis(aminomethyl)benzene and N-(3-dimethylaminopropyl)-1,2-bis(aminomethyl)benzene.

[0027] The substituents on the benzene ring are preferably in the 1,3- or 1,4-position, in particular in the 1,3-position.

[0028] Of these, N-(3-dimethylaminopropyl)-1,3-bis(aminomethyl)benzene or N-(3-dimethylaminopropyl)-1,4-bis(aminomethyl)benzene is preferred.

[0029] The amine of formula (I) is preferably a component of a reaction product obtained from the reductive alkylation of at least one amine of formula (II) with at least one benzonitrile of formula (III) and hydrogen, where n, R and A have the meanings already mentioned.

[0030] The preferred amine of the formula (II) is dimethylamine, 2-dimethylaminoethylamine, 3-dimethylamino-2-propylamine, 3-dimethylaminopropylamine (DMAPA), 4-dimethylaminobutylamine, 5-dimethylaminopentylamine or 3-(3-(dimethylamino)propyl-amino)propylamine (DMAPAPA).

[0031] Particularly preferred is dimethylamine, 2-dimethylaminoethylamine or 3-dimethylaminopropylamine (DMAPA), in particular DMAPA.

[0032] Suitable benzonitriles of formula (III) are 2-formylbenzonitrile, 3-formylbenzonitrile, 4-formylbenzonitrile, 2-acetylbenzonitrile, 3-acetylbenzonitrile, or 4-acetylbenzonitrile. Preferred are 2-formylbenzonitrile, 3-formylbenzonitrile, or 4-formylbenzonitrile, especially 3-formylbenzonitrile or 4-formylbenzonitrile, and most preferred is 3-formylbenzonitrile.

[0033] The amine of formula (II) and the benzonitrile of formula (III) are preferably used approximately stoichiometrically, in particular in the molar ratio between the amine of formula (II) and the benzonitrile of formula (III) of 0.9 / 1 to 1.1 / 1, preferably 0.9 / 1 to 1.0 / 1.

[0034] Reductive alkylation can be carried out directly with molecular hydrogen or indirectly by hydrogen or hydride transfer from other reagents such as formic acid or LiAlH 4 . Molecular hydrogen is preferred.

[0035] The reaction conditions are advantageously selected so that the nitrile group is also hydrogenated and the benzene ring is not hydrogenated. The reaction is preferably carried out at a temperature of 40 to 120 °C and in the presence of a suitable catalyst. Preferred catalysts are palladium on carbon (Pd / C), platinum on carbon (Pt / C), Adams catalyst, or Raney nickel, especially palladium on carbon or Raney nickel.

[0036] When using molecular hydrogen, it is preferable to work in a pressure apparatus at a hydrogen pressure of 5 to 150 bar, in particular 10 to 120 bar.

[0037] Preferably, the volatile components, in particular any solvent and water present, are removed from the reaction product after the reaction, in particular by distillation or stripping.

[0038] The reaction product can be further purified, particularly by distillation. This yields a reaction product with a particularly high content of amine of formula (I).

[0039] The reaction product preferably contains an amine of formula (I) content of at least 70% by weight, particularly preferably at least 80% by weight, in particular at least 90% by weight.

[0040] The reaction product may contain the following compounds as by-products: Compounds with imine and / or nitrile groups from the incomplete hydrogenation of the intermediates, in the case of n=1 for example of the formula Amines of the formula with hydrogenated benzene ring, amino alcohols of the formula from the hydrogenation of unreacted benzonitrile of formula (III), multiply alkylated amines, such as in the case of DMAPA and 3-formylbenzonitrile the following:

[0041] The amine of formula (I) is low-odor and low-viscosity.

[0042] The amine of formula (I), in particular in the form of the described reaction product, is used for curing epoxy resins.

[0043] Suitable epoxy resins are in particular glycidyl ethers of commercially available mono- or polyfunctional alcohols or phenols, in particular the epoxy resins mentioned in this document.

[0044] Preferably, the amine of formula (I), the epoxy resin and optionally further substances are mixed with one another, the ratio of the groups reactive towards the epoxy groups, in particular the amine hydrogens of the amine of formula (I), and the epoxy groups preferably being in the range from 0.5 to 1.5, in particular 0.7 to 1.2.

[0045] Curing can take place at ambient temperature, in particular in the range of 5 to 40 °C, or at elevated temperature, in particular in the range of 40 to 150 °C, preferably 50 to 120 °C.

[0046] The amine of formula (I) enables surprisingly fast and trouble-free curing and high final hardness, producing beautiful, defect-free surfaces with a high gloss even when applied over large areas and at cold temperatures.

[0047] The amine of formula (I) can be used in combination with other hardeners.

[0048] The amine of formula (I) can be used in a form partially adducted with at least one epoxy resin or monoepoxide, in particular with an epoxy resin or monoepoxide having an average epoxy equivalent weight in the range from 150 to 500 g / eq, preferably 156 to 250 g / eq.

[0049] Preference is given to amine-functional adducts from the reaction of at least one amine of the formula (I) and at least one epoxy resin in a stoichiometric ratio in the range from 1 to 10, preferably 1 to 5, mol of amine of the formula (I) per mole equivalent of epoxy groups.

[0050] Another object of the invention is a hardener for epoxy resins containing at least one amine of the formula (I) and at least one further component selected from further amines A1, Accelerators and thinners.

[0051] The further amine is preferred A1 no amine of formula (I).

[0052] The hardener preferably contains 1 to 99% by weight, more preferably 2 to 90% by weight, more preferably 3 to 75% by weight, particularly preferably 5 to 50% by weight, in particular 7 to 30% by weight, of amine of formula (I), based on the total hardener.

[0053] The hardener is preferably not water-based. It preferably contains less than 15% by weight, especially less than 10% by weight, of water, based on the total hardener. Such a hardener is particularly suitable for non-aqueous epoxy resin products.

[0054] Suitable further amines are in particular amines having at least two, preferably at least three, amine hydrogens which do not correspond to formula (I).

[0055] The hardener preferably contains at least one further amine A1 which has at least three aliphatic amine hydrogens.

[0056] Particularly suitable for this purpose are N-benzyl-1,2-ethanediamine, N-benzyl-1,2-propanediamine, N-benzyl-bis(aminomethyl)-1,3-benzene, N-(2-phenylethyl)-bis(aminomethyl)-1,3-benzene, N-(2-ethylhexyl)-bis(aminomethyl)-1,3-benzene, 2,2-dimethyl-1,3-propanediamine, 1,3-pentanediamine (DAMP), 1,5-pentanediamine, 1,5-diamino-2-methylpentane (MPMD), 2-butyl-2-ethyl-1,5-pentanediamine (C11-neodiamine), 1,6-hexanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,2(4),4-trimethyl-1,6-hexanediamine (TMD), 1,7-Heptanediamine, 1,8-Octanediamine, 1,9-Nonanediamine, 1,10-Decanediamine, 1,11-Undecanediamine, 1,12-Dodecanediamine, 1,2-, 1,3- or 1,4-Diaminocyclohexane, 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, 1-Amino-3-aminomethyl-3,5,5-trimethylcyclohexane (IPDA), 2(4)-Methyl-1,3-diaminocyclohexane, 2,5(2,6)-Bis(aminomethyl)-bicyclo[2.2.1]heptane (NBDA), 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0 2,6< ]decane, 1,4-diamino-2,2,6-trimethylcyclohexane (TMCDA), 1,8-mentanediamine, 3,9-Bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3-bis(aminomethyl)benzene (MXDA), 1,4-bis(aminomethyl)benzene, bis(2-aminoethyl)ether, 3,6-dioxaoctane-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-trioxatridecane-1,13-diamine or higher oligomers of these diamines, bis(3-aminopropyl)polytetrahydrofurans or other polytetrahydrofurandiamines, polyoxyalkylenedi- or triamines, in particular polyoxypropylenediamines or polyoxypropylenetriamines such as Jeffamine®< D-230, Jeffamine®< D-400 or Jeffamine®< T-403 (all from Huntsman), polyalkyleneamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), dipropylenetriamine (DPTA), N-(2-aminoethyl)-1,3-propanediamine (N3-amine), N,N'-bis(3-aminopropyl)ethylenediamine (N4-amine), N,N'-bis(3-aminopropyl)-1,4-diaminobutane, N5-(3-aminopropyl)-2-methyl-1,5-pentanediamine, N3-(3-aminopentyl)-1,3-pentanediamine, N5-(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine, N,N'-bis(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine, 3-(2-aminoethyl)aminopropylamine or bis(hexamethylene)triamine (BHMT), N-benzylated polyalkyleneamines with one or two benzyl groups, in particular benzylated DETA, TETA, N3-amine, N4-amine or DPTA, N-aminoethylpiperazine, 3-(3-(Dimethylamino)propylamino)propylamine (DMAPAPA), amine-functional adducts of the above-mentioned amines with epoxides, or mixtures of two or more of these amines.

[0057] The hardener preferably contains at least one further amine A1 selected from the group consisting of N-benzyl-1,2-ethanediamine, MPMD, TMD, 1,2-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, IPDA, 2(4)-methyl-1,3-diaminocyclohexane, NBDA, MXDA, DETA, TETA, TEPA, N3-amine, N4-amine, DPTA, BHMT, DMAPAPA, polyoxypropylenediamines having an average molecular weight M n in the range from 200 to 500 g / mol and polyoxypropylenetriamines having an average molecular weight M n in the range from 300 to 500 g / mol.

[0058] N-benzyl-1,2-ethanediamine is preferred, enabling coatings with particularly attractive surfaces.

[0059] MXDA, 1,3-bis(aminomethyl)cyclohexane, or 1,4-bis(aminomethyl)cyclohexane are also preferred. These enable particularly rapid curing.

[0060] IPDA remains the preferred choice. It provides a cost-effective hardener with a high glass transition temperature.

[0061] DETA, TETA, TEPA, or N4-amine remain preferred. These enable cost-effective adhesives with particularly high adhesive strength.

[0062] The hardener can in particular contain more than one additional amine A1 contain.

[0063] Suitable accelerators are, in particular, acids or compounds hydrolyzable to acids, in particular organic carboxylic acids such as acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid, lactic acid, organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid or 4-dodecylbenzenesulfonic acid, sulfonic acid esters, other organic or inorganic acids such as, in particular, phosphoric acid, or mixtures of the aforementioned acids and acid esters; nitrates such as, in particular, calcium nitrate; tertiary amines such as in particular 1,4-diazabicyclo[2.2.2]octane, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminopropylamine, imidazoles such as in particular N-methylimidazole, N-vinylimidazole or 1,2-dimethylimidazole, salts of such tertiary amines, quaternary ammonium salts such as in particular benzyltrimethylammonium chloride, amidines such as in particular 1,8-diazabicyclo[5.4.0]-undec-7-ene, guanidines such as in particular 1,1,3,3-tetramethylguanidine, phenols, in particular bisphenols, phenol resins or Mannich bases such as in particular 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol or polymers of phenol, formaldehyde and N,N-dimethyl-1,3-propanediamine, phosphites such as in particular di- or triphenyl phosphites, or compounds containing mercapto groups.

[0064] Preferred accelerators are acids, nitrates, tertiary amines or Mannich bases, in particular salicylic acid, calcium nitrate or 2,4,6-tris(dimethylaminomethyl)phenol, or a combination of these accelerators.

[0065] Suitable thinners are in particular n-propanol, isopropanol, n-butanol, isobutanol, tert.Butanol, 1-Pentanol, 2-Pentanol, 3-Pentanol, 2-Methyl-1-butanol, 3-Methyl-1-butanol, 3-Methyl-2-butanol n-Hexanol, 2-Ethylhexanol, Xylol, 2-Methoxyethanol, Dimethoxyethanol, 2-Ethoxyethanol, 2-Propoxyethanol, 2-Isopropoxyethanol, 2-Butoxyethanol, 2-Phenoxyethanol, 2-Benzyloxyethanol, Benzylalkohol, Ethylenglykol, Ethylenglykoldimethylether, Ethylenglykoldiethylether, Ethylenglykoldibutylether, Ethylenglykoldiphenylether, Diethylenglykol, Diethylenglykolmonomethylether, Diethylenglykolmonoethylether, Diethylenglykolmono-n-butylether, Diethylenglykoldimethylether, Diethylenglykoldiethylether, Diethylenglykoldi-n-butylylether, Propylenglykolbutylether, Propylenglykolphenylether, Dipropylenglykol, Dipropylenglykolmonomethylether, Dipropylenglykoldimethylether, Dipropylenglykoldi-n-butylether, 2,2,4-Trimethyl-1,3-pentandiolmonoisobutyrat, Diphenylmethan, Diisopropylnaphthalin, Erdölfraktionen wie zum Beispiel Solvesso ®< -Typen (von Exxon), Alkylphenole wie tert.Butylphenol, nonylphenol, dodecylphenol, cardanol, styrenated phenol, bisphenols, aromatic hydrocarbon resins, in particular types containing phenol groups, alkoxylated phenol, in particular ethoxylated or propoxylated phenol, in particular 2-phenoxyethanol, adipates, sebacates, phthalates, benzoates, organic phosphoric or sulfonic acid esters or sulfonamides.

[0066] Of these, preference is given to thinners having a boiling point of more than 200 °C, in particular benzyl alcohol, styrenated phenol, ethoxylated phenol, aromatic hydrocarbon resins containing phenol groups, such as in particular the Novares ® types LS 500, LX 200, LA 300 or LA 700 (from Rütgers), diisopropylnaphthalene or cardanol, in particular benzyl alcohol.

[0067] Phenol group-containing thinners also act as accelerators.

[0068] The hardener may contain other ingredients, in particular: other adducts, in particular adducts of MPMD or 1,2-ethanediamine or 1,2-propanediamine with cresyl glycidyl ether or aromatic epoxy resins, in which unreacted MPMD, 1,2-ethanediamine or 1,2-propanediamine was removed by distillation after the reaction, monoamines such as in particular benzylamine or furfurylamine, polyamidoamines, in particular reaction products of a mono- or polybasic carboxylic acid or its ester or anhydride, in particular a dimer fatty acid, with a polyamine used in stoichiometric excess, in particular DETA or TETA, Mannich bases, in particular phenalkamines, i.e. reaction products of phenols, in particular cardanol, with aldehydes, in particular formaldehyde, and polyamines, aromatic polyamines such as in particular 4,4'-, 2,4' and / or 2,2'-diaminodiphenylmethane, 2,4(6)-toluenediamine, 3,5-dimethylthio-2,4(6)-toluenediamine or 3,5-diethyl-2,4(6)-toluenediamine, compounds containing mercapto groups,in particular liquid mercaptan-terminated polysulfide polymers, mercaptan-terminated polyoxyalkylene ethers, mercaptan-terminated polyoxyalkylene derivatives, polyesters of thiocarboxylic acids, 2,4,6-trimercapto-1,3,5-triazine, triethylene glycol dimercaptan or ethanedithiol, surface-active additives, in particular defoamers, deaerators, wetting agents, dispersants or leveling agents, or stabilizers, in particular stabilizers against oxidation, heat, light or UV radiation.

[0069] Another object of the invention is an epoxy resin composition comprising a resin component containing at least one epoxy resin and a hardener component containing at least one amine of the formula (I) or a hardener containing at least one amine of the formula (I) as described above.

[0070] A suitable epoxy resin is obtained in a known manner, in particular from the reaction of epichlorohydrin with polyols, polyphenols or amines.

[0071] Suitable epoxy resins are in particular aromatic epoxy resins, in particular the glycidyl ethers of: Bisphenol A, bisphenol F or bisphenol A / F, where A stands for acetone and F for formaldehyde, which served as starting materials for the production of these bisphenols. In the case of bisphenol F, positional isomers may also be present, in particular derived from 2,4'- or 2,2'-hydroxyphenylmethane, dihydroxybenzene derivatives such as resorcinol, hydroquinone or pyrocatechol; other bisphenols or polyphenols such as bis(4-hydroxy-3-methylphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C), bis(3,5-dimethyl-4-hydroxyphenyl)methane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-tert.butylphenyl) propane, 2,2-bis(4-hydroxyphenyl)butane (bisphenol-B), 3,3-bis(4-hydroxyphenyl)pentane, 3,4-bis(4-hydroxyphenyl)hexane, 4,4-bis(4-hydroxyphenyl)heptane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,4-Bis(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane, 1,1-Bis(4-hydroxyphenyl)cyclohexane (Bisphenol-Z), 1,1-Bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (Bisphenol-TMC), 1,1-Bis(4-hydroxyphenyl)-1-phenylethane, 1,4-Bis[2-(4-hydroxyphenyl)-2-propyl]-benzene (Bisphenol-P), 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (bisphenol-M), 4,4'-dihydroxydiphenyl (DOD), 4,4'-dihydroxybenzophenone, bis(2-hydroxy-naphth-1-yl)methane, bis(4-hydroxynaphth-1-yl)methane, 1,5-dihydroxynaphthalene, tris(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)ether or bis(4-hydroxyphenyl)sulfone; novolaks, which are in particular condensation products of phenol or cresols with formaldehyde orParaformaldehyde or acetaldehyde or crotonaldehyde or isobutyraldehyde or 2-ethylhexanal or benzaldehyde or furfural; aromatic amines such as aniline, toluidine, 4-aminophenol, 4,4'-methylenediphenyldiamine, 4,4'-methylenediphenyldi-(N-methyl)amine, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline (bisaniline-P) or 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline (bisaniline-M).

[0072] Other suitable epoxy resins are aliphatic or cycloaliphatic polyepoxides, in particular Glycidyl ethers of saturated or unsaturated, branched or unbranched, cyclic or open-chain di-, tri- or tetrafunctional C 2 - to C 30 -alcohols, in particular ethylene glycol, propylene glycol, butylene glycol, hexanediol, octanediol, polypropylene glycols, dimethylolcyclohexane, neopentyl glycol, dibromoneopentyl glycol, castor oil, trimethylolpropane, trimethylolethane, pentaerythrol, sorbitol or glycerol, or alkoxylated glycerol or alkoxylated trimethylolpropane; a hydrogenated bisphenol A, F or A / F liquid resin, or the glycidylation products of hydrogenated bisphenol A, F or A / F; an N-glycidyl derivative of amides or heterocyclic nitrogen bases, such as triglycidyl cyanurate or triglycidyl isocyanurate, or reaction products of epichlorohydrin with hydantoin.

[0073] Preferably, the epoxy resin is a liquid resin or a mixture containing two or more epoxy liquid resins.

[0074] An "epoxy liquid resin" is a technical polyepoxide with a glass transition temperature below 25 °C.

[0075] If necessary, the resin component also contains portions of solid epoxy resin.

[0076] The epoxy resin is in particular a liquid resin based on a bisphenol or novolak, in particular with an average epoxy equivalent weight in the range of 156 to 210 g / eq.

[0077] Bisphenol A diglycidyl ether and / or bisphenol F diglycidyl ether, such as those commercially available from Olin, Huntsman, or Momentive, are particularly suitable. These liquid resins have a low viscosity for an epoxy resin and enable rapid curing and high hardness. They can contain portions of bisphenol A solid resin or novolak epoxy resins.

[0078] Also particularly suitable are phenol-formaldehyde novolak glycidyl ethers, in particular with an average functionality in the range of 2.3 to 4, preferably 2.5 to 3. They may contain proportions of other epoxy resins, in particular bisphenol A diglycidyl ether or bisphenol F diglycidyl ether.

[0079] The resin component may contain a reactive diluent.

[0080] Preferred reactive diluents are reactive diluents containing epoxy groups, in particular butanediol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane di- or triglycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, guaiacol glycidyl ether, 4-methoxyphenyl glycidyl ether, pn-butylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, 4-nonylphenyl glycidyl ether, 4-dodecylphenyl glycidyl ether, cardanol glycidyl ether, benzyl glycidyl ether, allyl glycidyl ether, butyl glycidyl ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether, or glycidyl ethers of natural alcohols such as in particular C 8 - to C 10 - or C 12 - to C 14 - or C 13 - to C 15 -alkyl glycidyl ethers.

[0081] The epoxy resin composition preferably contains at least one further component selected from the group consisting of thinners, accelerators, stabilizers, surface-active additives, fillers and pigments.

[0082] The above-mentioned additives are particularly suitable as thinners, accelerators, stabilizers and surface-active additives.

[0083] Suitable fillers include, in particular, ground or precipitated calcium carbonate, optionally coated with fatty acids, especially stearates, barite (barite), talc, quartz flour, quartz sand, silicon carbide, iron mica, dolomite, wollastonite, kaolin, mica (potassium aluminum silicate), molecular sieves, aluminum oxide, zinc oxide, aluminum-doped zinc oxide, aluminum hydroxide, magnesium hydroxide, silica, cement, gypsum, fly ash, carbon black, graphite, wood flour, metal powders such as aluminum, copper, iron, zinc, silver, or steel, PVC powder, or hollow spheres. Preferred fillers are calcium carbonate, barite, quartz flour, talc, or a combination thereof.

[0084] Suitable pigments are in particular titanium dioxide, iron oxides, chromium(III) oxides, anti-corrosive pigments, organic pigments or carbon black, in particular titanium dioxide.

[0085] The epoxy resin composition may contain other auxiliary substances and additives, in particular the following: Reactive diluents, in particular those already mentioned, or epoxidized soybean oil or linseed oil, compounds containing acetoacetate groups, in particular acetoacetylated polyols, butyrolactone, carbonates, aldehydes, isocyanates or silicones containing reactive groups; polymers, in particular polyamides, polysulfides, polyvinyl formal (PVF), polyvinyl butyral (PVB), polyurethanes (PUR), polymers with carboxyl groups, polyamides, butadiene-acrylonitrile copolymers, styrene-acrylonitrile copolymers, butadiene-styrene copolymers, homo- or copolymers of unsaturated monomers, in particular from the group comprising ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or alkyl (meth)acrylates, in particular chlorosulfonated polyethylenes or fluorine-containing polymers or sulfonamide-modified melamines; Fibres, in particular glass fibres, carbon fibres, cellulose fibres, metal fibres, ceramic fibres or plastic fibres such as polyamide fibres or polyethylene fibres; other solids,in particular wood granules or cellulose; nanofillers, in particular carbon nanotubes; rheology modifiers, in particular thickeners or anti-settling agents; adhesion promoters, in particular organoalkoxysilanes; flame-retardant substances, in particular the fillers already mentioned: aluminium hydroxide or magnesium hydroxide, antimony trioxide, antimony pentoxide, boric acid (B(OH)3), zinc borate, zinc phosphate, melamine borate, melamine cyanurate, ammonium polyphosphate, melamine phosphate, melamine pyrophosphate, polybrominated diphenyl oxides or diphenyl ethers, phosphates such as in particular diphenyl cresyl phosphate, resorcinol bis(diphenyl phosphate), resorcinol diphosphate oligomer, tetraphenylresorcinol diphosphite, ethylenediamine diphosphate, bisphenol A bis(diphenyl phosphate), tris(chloroethyl)phosphate, tris(chloropropyl)phosphate, tris(dichloroisopropyl)phosphate, tris[3-bromo-2,2-bis(bromomethyl)propyl]phosphate, tetrabromobisphenol A, bis(2,3-dibromopropyl ether) of bisphenol A, brominated epoxy resins,Ethylene bis(tetrabromophthalimide), ethylene bis(dibromonorbornane dicarboximide), 1,2-bis(tribromophenoxy)ethane, tris(2,3-dibromopropyl)isocyanurate, tribromophenol, hexabromocyclododecane, bis(hexachlorocyclopentadieno)cyclooctane or chlorinated paraffins; or other additives, in particular dispersed paraffin wax or biocides.

[0086] The epoxy resin composition preferably contains only a low content of thinners. It preferably contains less than 30% by weight, more preferably less than 20% by weight, and in particular less than 10% by weight of thinner, based on the total epoxy resin composition.

[0087] Preferably, the epoxy resin composition contains only a small amount of water, preferably less than 5% by weight, in particular less than 1% by weight, of water, based on the total epoxy resin composition.

[0088] The resin and hardener components of the epoxy resin composition are stored in separate containers. Other components of the epoxy resin composition may be present as components of the resin or hardener components, with additional components that are reactive toward epoxy groups preferably being part of the hardener component. It is also possible for other components to be present as separate components.

[0089] A suitable container for storing the resin or hardener components is, in particular, a drum, a hobbock, a bag, a bucket, a can, a cartridge, or a tube. The components are storable, meaning they can be stored for several months up to a year or longer before use without their respective properties changing to an extent relevant to their intended use.

[0090] The resin and hardener components are mixed shortly before or during application. The mixing ratio is preferably selected such that the molar ratio of the groups reactive toward epoxy groups to the epoxy groups is in the range of 0.5 to 1.5, particularly 0.7 to 1.2. In parts by weight, the mixing ratio between the resin and hardener components is typically in the range of 1:2 to 20:1.

[0091] The components are mixed continuously or batchwise using a suitable process, ensuring that there is not too much time between mixing the components and application and that application occurs within the pot life. Mixing and application can take place at ambient temperature, which is typically in the range of about 5 to 40 °C, preferably about 10 to 35 °C, or at elevated temperature, in particular in the range of 40 to 150 °C, preferably 50 to 120 °C.

[0092] With the mixing of the components, the curing of the epoxy resin composition begins through a chemical reaction. Primary and secondary amino groups, and any other epoxy-reactive groups present, react with the epoxy groups, causing their ring opening. As a result of these reactions, the composition polymerizes and thus cures.

[0093] Curing typically takes several hours to several days. The duration depends, among other things, on the temperature, the reactivity of the components, their stoichiometry, and the presence or amount of accelerators. The amine of formula (I) enables particularly rapid curing, especially at cold temperatures.

[0094] In the freshly mixed state, the epoxy resin composition has a low viscosity. The viscosity 5 minutes after mixing the resin and hardener components at 20 °C is preferably in the range of 0.2 to 20 Pa s, preferably 0.3 to 10 Pa s, especially 0.3 to 5 Pa s, measured using a cone-and-plate viscometer at a shear rate of 10 s -1< .

[0095] The epoxy resin composition is applied to at least one substrate and / or into at least one casting mold.

[0096] Particularly suitable as substrates are: Glass, glass ceramics, concrete, mortar, cement screed, fiber cement, brick, tile, plaster or natural stones such as granite or marble; repair or leveling compounds based on PCC (polymer-modified cement mortar) or ECC (epoxy resin-modified cement mortar); metals or alloys such as aluminum, iron, steel, copper, other non-ferrous metals, including surface-treated metals or alloys such as galvanized or chrome-plated metals; asphalt or bitumen; leather, textiles, paper, wood, wood materials bonded with resins, for example phenolic, melamine or epoxy resins, resin-textile composites or other so-called polymer composites; Plastics such as rigid and soft PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM or EPDM, each untreated or surface-treated, for example by means of plasma, corona or flames;Fiber-reinforced plastics, such as carbon fiber-reinforced plastics (CFRP), glass fiber-reinforced plastics (GRP) and sheet molding compounds (SMC); insulating foams, in particular made of EPS, XPS, PUR, PIR, rock wool, glass wool or foamed glass (foam glass); coated or painted substrates, in particular painted tiles, painted concrete, powder-coated metals or alloys or painted sheets; coatings, paints or varnishes, in particular coated floors which are covered with another floor covering layer.

[0097] If necessary, the substrates may be pretreated before application, in particular by physical and / or chemical cleaning processes or the application of an activator or a primer.

[0098] The substrates are in particular coated and / or glued.

[0099] A suitable casting mold is a device into which the mixed, liquid epoxy resin composition is poured and cured therein and, after curing, can be demolded or removed therefrom, whereby the cured composition forms a molded body.

[0100] A further object of the invention is a cured composition obtained from the described epoxy resin composition after mixing the resin and hardener components.

[0101] The epoxy resin composition is preferably used as a coating, primer, adhesive, sealant, potting compound, casting resin, impregnating resin, or as a molded body or matrix for composite materials such as, in particular, CFRP (containing carbon fibers) or GFRP (containing glass fibers) or wood composite material.

[0102] Another object of the invention is a method for coating, comprising the steps (i) applying the mixed epoxy resin composition to at least one substrate, (ii) optionally applying a further layer of the mixed epoxy resin coating to the cured layer.

[0103] The ones already mentioned are suitable as substrates.

[0104] The epoxy resin composition is preferably used as a primer, with the substrate being, in particular, concrete, mortar, cement screed, or a metal, especially steel. Such an epoxy resin composition is preferably largely free of fillers and serves to consolidate the substrate, seal any pores, and ensure good adhesion between the substrate and other layers.

[0105] Furthermore, the epoxy resin composition is preferably used as a floor coating. Such an epoxy resin composition preferably contains fillers and pigments and is applied over the entire surface in one or more steps, in particular in a layer thickness of 0.1 to 5 mm, preferably as a self-leveling coating, and allowed to cure. The substrate is preferably concrete, mortar, or cement screed, optionally pretreated with a primer or undercoat.

[0106] Furthermore, the epoxy resin coating is preferably used as a protective coating, in particular as a corrosion protection coating on steel or as a topcoat on floor coatings. Such a coating is preferably applied by spraying, in particular in a layer thickness of 0.05 to 0.5 mm.

[0107] Another object of the invention is a method for bonding, comprising applying the mixed epoxy resin composition, either onto at least one of the substrates to be bonded and joining the substrates to form a bond, or into a cavity or gap between several substrates and, if necessary, inserting an anchor into the cavity or gap.

[0108] An "anchor" refers, in particular, to a reinforcing bar, threaded rod, or bolt. Such an anchor is typically glued or anchored into a wall, ceiling, or foundation in such a way that part of it is firmly bonded and part protrudes and can bear structural loads.

[0109] Similar or different substrates can be bonded.

[0110] Another object of the invention is a process for producing a shaped body, comprising introducing the mixed epoxy resin composition into a casting mold, followed by curing the mixed composition, optionally under pressure and optionally by means of added heat.

[0111] Before curing, the epoxy resin composition can be mixed with fibers, powders, or granules, particularly carbon fibers, glass fibers, or wood powder and / or granules, to create a composite material. The molded body can be produced in a single casting in the mold or it can be built up in layers.

[0112] After curing, the molded body is preferably removed from the mold. It can be further processed, particularly by cutting, drilling, drawing, grinding, or polishing.

[0113] An article is produced from the use of an amine of formula (I) for curing epoxy resins or from a process for coating, bonding or producing a shaped body.

[0114] The article is preferably a building or a part thereof, in particular a building or civil engineering structure, an office, an industrial hall, a gymnasium, a cold storage room, a silo, a bridge, a roof, a staircase, a floor, a balcony, a terrace or a parking deck, or an industrial good or a consumer good, in particular a slat, a panel, a pier, an offshore platform, a lock gate, a crane, a sheet pile wall, a pipeline, a vessel or a rotor blade of a wind turbine, or a means of transport such as in particular an automobile, a truck, a rail vehicle, a ship, an aircraft or a helicopter, or an attachment thereof.

[0115] The amine of formula (I) is preferably used as a hardener, co-hardener and / or incorporable accelerator.

[0116] Another object of the invention is an amine of formula (Ia), where m is 1 or 2, R is H or methyl and A is an alkylene radical having 2 to 6 C atoms.

[0117] Preferably, m stands for 1.

[0118] Preferably, R is H.

[0119] A preferably represents 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene or 1,5-pentylene, particularly preferably 1,2-ethylene or 1,3-propylene, in particular 1,3-propylene.

[0120] Preferably, the amine of formula (Ia) is selected from the group consisting of N-(2-dimethylaminoethyl)-1,3-bis(aminomethyl)benzene, N-(3-dimethylaminopropyl)-1,3-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,4-bis(aminomethyl)benzene, N-(3-dimethylaminopropyl)-1,4-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,2-bis(aminomethyl)benzene and N-(3-dimethylaminopropyl)-1,2-bis(aminomethyl)benzene.

[0121] The substituents on the benzene ring are preferably in the 1,3- or 1,4-position.

[0122] Particularly preferred amine of formula (Ia) is N-(3-dimethylaminopropyl)-1,3-bis(aminomethyl)benzene or N-(3-dimethylaminopropyl)-1,4-bis(aminomethyl)benzene.

[0123] Another object of the invention is a reaction product containing at least one amine of formula (Ia), obtained from the reductive alkylation of at least one amine of formula (IIa) with at least one benzonitrile of formula (III) and hydrogen, where m, R and A have the meanings already mentioned.

[0124] The preferred amine of the formula (IIa) is 2-dimethylaminoethylamine, 3-dimethylamino-2-propylamine, 3-dimethylaminopropylamine (DMAPA), 4-dimethylaminobutylamine, 5-dimethylaminopentylamine or 3-(3-(dimethylamino)propylamino)-propylamine (DMAPAPA).

[0125] Particularly preferred is 2-dimethylaminoethylamine DMAPA, especially DMAPA.

[0126] Suitable benzonitriles of formula (III) are 2-formylbenzonitrile, 3-formylbenzonitrile, 4-formylbenzonitrile, 2-acetylbenzonitrile, 3-acetylbenzonitrile, or 4-acetylbenzonitrile. Preferred are 2-formylbenzonitrile, 3-formylbenzonitrile, or 4-formylbenzonitrile, especially 3-formylbenzonitrile or 4-formylbenzonitrile, and most preferred is 3-formylbenzonitrile.

[0127] The amine of formula (II) and the benzonitrile of formula (III) are preferably used approximately stoichiometrically, in particular in the molar ratio between the amine of formula (II) and the benzonitrile of formula (III) of 0.9 / 1 to 1.1 / 1, preferably 0.9 / 1 to 1.0 / 1.

[0128] The reductive alkylation is carried out as previously described.

[0129] The reaction product can be further purified, in particular by distillation. This yields a reaction product with a particularly high content of amine of formula (Ia).

[0130] The reaction product preferably contains an amine of formula (Ia) content of at least 70% by weight, particularly preferably at least 80% by weight, in particular at least 90% by weight.

[0131] The amine of formula (Ia) is low-odor and low-viscosity.

[0132] The amine of formula (Ia), in particular in the form of the reaction product described, is preferably used for curing epoxy resins. Examples

[0133] The following are exemplary embodiments intended to further illustrate the described invention. Of course, the invention is not limited to these described exemplary embodiments.

[0134] "AHEW" stands for amine hydrogen equivalent weight.

[0135] "EEW" stands for epoxy equivalent weight.

[0136] The "standard climate" ("NK") is defined as a temperature of 23±1 °C and a relative humidity of 50±5%.

[0137] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH. Description of the measurement methods:

[0138] The viscositywas measured on a thermostatted Rheotec RC30 cone-and-plate viscometer (cone diameter 50 mm, cone angle 1°, cone tip-to-plate distance 0.05 mm). Low-viscosity samples with a viscosity of less than 100 mPa s were measured at a shear rate of 100 s -1<, while higher-viscosity samples were measured at a shear rate of 10 s -1<.

[0139] The Amine number was determined by titration (with 0.1N HClO 4 in acetic acid against crystal violet).

[0140] Gas chromatograms (GC) were measured in the temperature range from 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 was used (L = 30 m, ID = 0.25 mm, dj = 0.5 µm) at a gas flow of 1.5 ml / min. Detection was performed by flame ionization (FID).

[0141] Infrared spectra(FTIR) were measured on undiluted films using a Thermo Scientific Nicolet iS5 FTIR instrument equipped with a horizontal diamond crystal ATR measurement unit. Absorption bands are given in wavenumbers (cm -1< ).

[0142] 1< H-NMR spectra were measured on a Bruker Ascend 400 spectrometer at 400.14 MHz; chemical shifts δ are given in ppm relative to tetramethylsilane (TMS). True and pseudo-coupling patterns were not distinguished. Preparation of amines of formula (I): Amine A1: N-(3-Dimethylaminopropyl)-1,3-bis(aminomethyl)benzene

[0143] 39.2 g (0.30 mol) of 3-formylbenzonitrile (= 3-cyanobenzaldehyde) were dissolved in 750 ml of isopropyl alcohol at 40 °C under a nitrogen atmosphere. 32.0 g (0.315 mol) of 3-dimethylaminopropylamine (DMAPA, from Arkema) were then slowly added with stirring, and the mixture was subsequently stirred for 1 hour. The reaction mixture was then hydrogenated at 65 °C, 75 bar hydrogen pressure, and a flow rate of 5 ml / min on a continuously operating hydrogenation apparatus equipped with a Raney nickel fixed-bed catalyst. The hydrogenated solution was concentrated on a rotary evaporator at 65 °C, removing unreacted 3-dimethylaminopropylamine, water, and isopropanol. 59.9 g of a yellowish oil with a viscosity of 42 mPa s at 20 °C were obtained.

[0144] 49.9 g of the resulting oil were subsequently purified by distillation, whereby 27.3 g of distillate were obtained as a clear, colorless oil at 117 to 120 °C (steam temperature) and 0.06 mbar with a viscosity at 20 °C of 28 mPa s, an amine number of 732 mg KOH / g and a content of N-dimethylaminopropyl-1,3-bis(aminomethyl)benzene determined by GC of > 97% (retention time 13.2 min) and a calculated AHEW of 73.7 g / eq, which is referred to below as amine A1 was used.

[0145] 1< H-NMR (CDCl 3 ): 7.28 (m, 2 H, Ar-H), 7.20 (m, 2 H, Ar-H), 3.85 (d, 2 H, Ar-CH 2 -N), 3.79 (s, 2 H, Ar-CH 2 -N), 2.68 (t, 2 H, CH 2 -N), 2.32 (t, 2 H, CH 2 -N(CH 3 )), 2.21 (s, 6 H, CH 3 ), 1.75 (br s, 3 H, NH) , 1.68 (m, 2 H, C-CH 2 -C) FT-IR: 3274, 3023, 2936, 2855, 2812, 2763, 1607, 1589, 1457, 1443, 1376, 1261, 1153, 1114, 1040, 837, 780, 738, 698 Amine A2: N-(3-(Dimethylamino)propylamino)propyl-1,3-bis(aminomethyl)benzene

[0146] The Amine A2 was like for Amin A1 described, but using 26.2 g (0.20 mol) of 3-formylbenzonitrile (= 3-cyanobenzaldehyde), 750 ml of isopropanol, and 33.4 g (0.21 mol) of 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA, from Arkema) instead of 3-dimethylaminopropylamine. This yielded 49.8 g of a yellowish oil with a viscosity of 42 mPa s at 20 °C, which was purified by distillation.

[0147] At 148 to 152 °C (steam temperature) and 0.06 mbar, 26.7 g of distillate were obtained as a clear, colorless oil with a viscosity at 20 °C of 81 mPa s, an amine number of 794 mg KOH / g and a content of N-(3-(dimethyl-amino)propylamino)propyl-1,3-bis(aminomethyl)benzene determined by GC of > 97% (retention time 15.5 min) and a calculated AHEW of 69.6 g / eq, which is referred to below as amine A2 was used.

[0148] 1< H-NMR (CDCl 3 ): 7.27 (m, 2 H, Ar-H), 7.18 (m, 2 H, Ar-H), 3.85 (d, 2 H, Ar-CH 2 -N), 3.77 (s, 2 H, Ar-CH 2 -N), 2.69 (m, 6 H, CH 2 -N), 2.29 (t, 2 H, CH 2 -N(CH 3 )), 2.19 (s, 6 H, CH 3 ) , 1.78 (br s, 4 H, NH) , 1.65 (m, 4 H, C-CH 2 -C)

[0149] FT-IR: 3294, 3050, 3024, 2912, 2813, 1605, 1588, 1451, 1355, 1336, 1154, 1111, 1027, 890, 779, 732, 696 Other substances and abbreviations used:

[0150] Araldite ®< GY 250: Bisphenol A diglycidyl ether, EEW 187 g / eql (from Huntsman) Araldite ®< DY-E: Monoglycidyl ether of C 12 to C 14 alcohols, EEW approx. 290 g / Eq (from Huntsman) DMAPAPA: 3-(3-(Dimethylamino)propylamino)propylamine, AHEW 53 g / Eq (DMAPAPA, from Arkema) B-EDA N-Benzyl-1,2-ethanediamine, prepared as described below, 150.2 g / mol, AHEW 50.1 g / eq IPDA: 1-Amino-3-aminomethyl-3,5,5-trimethylcyclohexane, AHEW 42.6 g / Eq (Vestamin ®< IPD, from Evonik) Ancamine ®< K54 2,4,6-Tris(dimethylaminomethyl)phenol (from Evonik) N-Benzyl-1,2-ethanediamine (B-EDA):

[0151] 180.3 g (3 mol) of 1,2-ethanediamine were initially charged at room temperature, mixed with a solution of 106.0 g (1 mol) of benzaldehyde in 1200 ml of isopropanol, and stirred for 2 hours. The mixture was then hydrogenated at 80 °C, 80 bar hydrogen pressure, and a flow rate of 5 ml / min on a continuously operating hydrogenation apparatus with a Pd / C fixed-bed catalyst. The hydrogenated solution was concentrated on a rotary evaporator at 65 °C, removing unreacted 1,2-ethanediamine, water, and isopropanol. The resulting reaction mixture was purified by distillation at 80 °C under vacuum. A colorless liquid was obtained with an N-benzyl-1,2-ethanediamine content of > 97%, determined by GC. Production of hardeners and epoxy resin compositions: Examples 1 and 2:

[0152] For each example, the resin component ingredients listed in Table 1 were mixed in the specified amounts (in parts by weight) using a centrifugal mixer (SpeedMixer™< DAC 150, FlackTek Inc.) and stored under exclusion of moisture.

[0153] The ingredients of the hardener component listed in Table 1 were also processed and stored.

[0154] The two components of each composition were then processed into a homogeneous liquid using the centrifugal mixer and immediately tested as follows: viscosity was measured 5 minutes after mixing the resin and hardener components as described at a temperature of 20 °C.

[0155] The Shore DHardness was determined according to DIN 53505 on two cylindrical test specimens (diameter 20 mm, thickness 5 mm), one stored in standard climate and one at 8 °C and 80% relative humidity, and the hardness was measured after 1 day (24 h) and after 2 days.

[0156] Furthermore, a film with a thickness of 500 µm was applied to a glass plate and stored and cured in a standard climate. King's hardness (Pendulum hardness according to König according to DIN EN ISO 1522) after 1 day, 2 days, 7 days and after 14 days (1d NK), (2d NK), (7d NK), (14d NK). After 14 days the Aspect (NK) of the film. A clear film was defined as having a glossy, non-sticky surface without any texture. "Texture" refers to any type of pattern or design on the surface.

[0157] The results are shown in Table 1. Table 1: Composition and properties of examples 1 and 2. 1< not measurable (too soft) Example 1 2 Resin component: Araldite ®< GY 250 167.2 167.2 Araldite ®< DY-E 31.8 31.8 Hardener component: Amine A1 73.7 - Amine A2 - 69.6 Viscosity (10') [Pa·s] 0.41 0.46 Shore D (1d NK) 67 51 (2d NK) 67 57 Shore D (1d 8° / 80%) 45 nm 1< (2d 8° / 80%) 47 46 King's hardness [s] (1d NK) 146 140 (2d NK) 155 143 (7d NK) 157 143 (14d NK) 157 144 Aspect (NK) nice nice Examples 3 to 6:

[0158] For each example, the resin and hardener components listed in Table 2 were mixed as described for Example 1 and the mixed components were tested as follows: Viscosity, Shore D, King hardness (NK) and Aspect (NK) were determined as described for Example 1.

[0159] The Setting time was determined by moving a freshly mixed amount of approximately 3 g in standard conditions with a spatula at regular intervals until the mass gelled.

[0160] In addition, another film with a layer thickness of 500 µm was applied to a glass plate and immediately after application, this was stored for 7 days at 8 °C and 80% relative humidity and then cured for 2 weeks in a standard climate. 24 hours after application, a polypropylene bottle cap was placed on the film, underneath which a moist sponge was placed. After another 24 hours, the sponge and cap were removed and placed in a new location on the film, where they were removed and re-placed after 24 hours, a total of 4 times. The appearance of this film was then assessed (in the tables with "Aspect (8° / 80%)"(denoted by the term "blushing"), in the same way as described for aspect (NK). The number and type of visible marks created in the film by the moist sponge or the applied lid were also reported. "Blushing" was the number of white stains. "(1)" was a faint, white stain. "1" was a distinct, white stain. "Ring" indicated whether a ring-shaped mark was present due to the sinking of the first lid applied 24 hours after application. Such a ring-shaped mark indicates that the coating is not yet walkable. "(yes)" was a very slight ring-shaped mark. "yes" was a distinct ring-shaped mark. The Königs hardness was again determined on the cured films, each after 7 days at 8 °C and 80% relative humidity. (Royal H. (7d 8° / 80%)), then after another 2 days in the NK (Royal H. (+2d NK))or 7 days in NK (Royal H. (+7d NK)) or 14d in NK (Royal H. (+14d NK)).

[0161] The results are shown in Table 2.

[0162] Comparative examples are "(Ref.)" designated. 3 6. Table 2: Composition and properties of the examples up to Example 3 4 5 (Ref.) 6 (Ref.) Resin component: Araldite ®< GY 250 167.2 167.2 167.2 167.2 Araldite ®< DY-E 31.8 31.8 31.8 31.8 Hardener component: Amine A1 22.1 11.1 - - DMAPAPA - - 8.0 - B-EDA - 7.5 7.5 15.0 IPDA 29.8 29.8 29.8 29.8 Benzyl alcohol 30.0 30.0 30.0 30.0 Salicylic acid 2.0 2.0 2.0 2.0 Ancamine ®< K54 - - - 2.0 Viscosity (10') [Pa·s] 0.54 0.49 0.43 0.46 Setting time (h:min) 3:30 4:00 4:00 4:00 Shore D (1d NK) 77 71 67 57 (2d NK) 79 76 73 74 Shore D (1d 8° / 80%) 33 13 11 9 (2d 8° / 80%) 76 69 63 61 King's hardness [s] (1d NK) 105 49 53 34 (2d NK) 157 119 118 85 (7d NK) 183 168 163 146 (14d NK) 185 181 172 158 Aspect (NK) nice nice nice nice Royal H. [s] (7d 8° / 80%) 105 59 49 32 (+2d NK) 164 153 131 106 (+7d NK) 175 167 147 137 (+14d NK) 183 160 143 137 Aspect (8° / 80%) nice nice cloudy nice Blushing (1) (1) 1 (1) ring (Yes) (Yes) Yes Yes

Claims

1. Use of an amine of the formula (I) for curing of epoxy resins, where n is 0 or 1 or 2, R is H or methyl and A is an alkylene radical having 2 to 6 carbon atoms.

2. Use according to Claim 1, characterized in that R is H.

3. Use according to either of Claims 1 and 2, characterized in that A is 1,2-ethylene or 1,3-propylene.

4. Use according to any of Claims 1 to 3, characterized in that n is 0 or 1.

5. Use according to any of Claims 1 to 4, characterized in that the amine of the formula (I) is selected from the group consisting of N,N-dimethyl-1,3-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,3-bis(aminomethyl)benzene, N-(3-dimethylaminopropyl)-1,3-bis(aminomethyl)benzene, N,N-dimethyl-1,4-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,4-bis(aminomethyl)benzene, N-(3-dimethylaminopropyl)-1,4-bis(aminomethyl)benzene, N,N-dimethyl-1,2-bis(aminomethyl)benzene, N-(2-dimethylaminoethyl)-1,2-bis(aminomethyl)benzene and N-(3-dimethylaminopropyl)-1,2-bis(aminomethyl)benzene.

6. Use according to any of Claims 1 to 5, characterized in that the amine of the formula (I) is a constituent of a reaction product obtained from the reductive alkylation of at least one amine of the formula (II) with at least one benzonitrile of the formula (III) and hydrogen.

7. Curing agent for epoxy resins comprising at least one amine of the formula (I) according to any of Claims 1 to 6 and at least one further constituent selected from further amines A1, accelerators, and thinners.

8. Curing agent according to Claim 7, characterized in that at least one further amine A1 is present, where the further amine A1 has at least three aliphatic amine hydrogens.

9. Epoxy resin composition comprising - a resin component comprising at least one epoxy resin and - a curing agent component comprising at least one amine of the formula (I) according to any of Claims 1 to 6 or a curing agent according to either of Claims 7 and 8.

10. Cured composition obtained from the epoxy resin composition according to Claim 9 after the resin component and the curing agent component have been mixed.

11. Method for coating, comprising the steps of (i) applying the mixed epoxy resin composition according to Claim 9 to at least one substrate, (ii) optionally applying a further layer of the mixed epoxy resin coating according to Claim 9 to the cured layer.

12. Method of bonding, comprising the applying of the mixed epoxy resin composition according to Claim 9 - either to at least one of the substrates to be bonded and joining the substrates to form a bond, - or into a cavity or gap between two or more substrates and optionally inserting an anchor into the cavity or gap.

13. Method of producing a shaped body, comprising the introducing of the mixed epoxy resin composition according to Claim 9 into a casting mold, followed by the curing of the mixed composition, optionally under pressure and optionally by means of supplied heat.

14. Amine of the formula (Ia), where m is 1 or 2, R is H or methyl, and A is an alkylene radical having 2 to 6 carbon atoms.

15. Reaction product comprising at least one amine of the formula (Ia), obtained from the reductive alkylation of at least one amine of the formula (IIa) with at least one benzonitrile of the formula (III) and hydrogen, where m is 1 or 2, R is H or methyl, and A is an alkylene radical having 2 to 6 carbon atoms.