BIO-BASED AMINE HARDENER FOR CURABLE COMPOSITIONS

Description

Technical field

[0001] The invention relates to the field of polyamines based on renewable raw materials, processes for their preparation and their use as hardeners for curable compositions, in particular for epoxy resins. State of the art

[0002] Multifunctional amines serve as hardeners for plastics and plastic compounds, for example, those based on epoxy resins, polyurethanes, polyureas, polyacrylates, or polyamides, for a wide range of applications in industry and construction. The amine hardener has a decisive influence on the properties of the plastic and must meet stringent requirements. For epoxy resins, for example, the amine hardener should enable good processability and rapid, trouble-free curing, resulting in cured plastic products of high quality, for example in terms of external appearance, glass transition temperature, water resistance, hardness, brittleness, or adhesion.The amine hardeners for epoxy resins known from the state of the art, such as 1,3-bis(aminomethyl)benzene, 1,3-bis(aminomethyl)cyclohexane, isophoronediamine or N-benzyl-1,2-ethanediamine, can be improved with regard to processability, open time, curing speed, trouble-free curing and / or surface quality.

[0003] Today, there is increasing demand for sustainable plastic products. In particular, they should contain a high proportion of raw materials from renewable sources, i.e., be largely biobased. A common measure of the sustainability of chemical raw materials is the Renewable Carbon Index (RCI), which indicates the proportion of carbon from renewable sources. It is calculated by dividing the number of carbon atoms from a renewable source by the total number of carbon atoms in the raw material. While bio-based epoxy resins such as glycerol triglycidyl ether or vanillin alcohol diglycidyl ether are well known, the selection of bio-based amine hardeners is still unsatisfactory, and their properties are inadequate compared to petroleum-based amine hardeners.

[0004] Furan-based amine hardeners are known from US 9,676,898 and WO 2015 / 124792. However, their starting materials are difficult to obtain and / or they are prone to blushing and / or lack dilution properties.

[0005] There is therefore a need for further bio-based amine hardeners with improved properties. Description of the invention

[0006] The object of the present invention is therefore to provide sustainable amine hardeners for plastics and plastic compositions which, compared to known petroleum-based amine hardeners, not only enable equivalent but even better properties, in particular with regard to processability and curing behavior.

[0007] Surprisingly, this object is achieved with a hardener comprising at least one amine of formula (I) as described in claim 1. Amines of formula (I) are accessible starting from vanillin or guaiacol, which are available from bio-based sources. The hardener according to the invention is suitable for plastics and plastic compositions, in particular based on epoxy resins, polyisocyanates, polyacrylates, or polyamides. It enables bio-based plastic products that are superior to petroleum-based ones not only in terms of sustainability but also in terms of technical performance. In epoxy resin products in particular, the hardener can replace conventional and widely used petroleum-based amine hardeners or accelerators such as MXDA or 2,4,6-tris(dimethylaminomethyl)phenol, thereby enabling additional advantages.The inventive hardener is surprisingly compatible with commonly used epoxy resins such as bisphenol A diglycidyl ether or bio-based vanillin alcohol diglycidyl ether. Compared to 1,3-bis(aminomethyl)phenol (MXDA), it enables significantly faster curing with significantly fewer surface defects due to blushing effects, and compared to 2,4,6-tris(dimethylaminomethyl)phenol, it enables a faster curing rate with lower odor.

[0008] 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 a curing agent containing at least one amine of formula (I) for crosslinking amine-reactive compounds, where represents a benzene ring or cyclohexane ring, R 1< stands for H or an alkyl radical having 1 to 6 C atoms, R 2< stands for H or a monovalent organic radical having 1 to 6 C atoms or an aminoalkyl radical having 2 to 10 C atoms or an N-substituted aminoalkyl radical having 2 to 10 C atoms, and R 3< stands for H or methyl.

[0010] An "amine-reactive compound" is a substance with reactive groups that can react with amino groups and, under the influence of the hardener, enters into chain building and crosslinking reactions that ultimately lead to curing.

[0011] The "RCI" refers to the "Renewable Carbon Index" of a substance or mixture of substances, where the RCI stands for the ratio of the number of C atoms from bio-based sources to the total number of C atoms of the substance or mixture of substances.

[0012] Substance names beginning with "poly", such as polyepoxide or polyisocyanate, refer to substances that formally contain two or more of the functional groups mentioned in their name per molecule.

[0013] 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.

[0014] The hydrogen atoms of primary and secondary amine groups are called "amine hydrogen".

[0015] The "amine hydrogen equivalent weight" is the mass of an amine or amine-containing composition containing one molar equivalent of amine hydrogen. It is expressed in the unit "g / eq."

[0016] 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."

[0017] A "thinner" is a substance that is soluble in an epoxy resin and reduces its viscosity, but is not chemically bound into the epoxy resin polymer during curing.

[0018] "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.

[0019] A temperature of 23 °C is referred to as “room temperature”.

[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] Weight percentages (wt%) 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] Amine-reactive compounds contain reactive groups such as, in particular, epoxy groups, isocyanate groups, acrylate groups, methacrylate groups, acrylamide groups, methacrylamide groups, carboxylic acid groups, carboxylic acid ester groups, acetoacetate groups, 1,3-diketo groups, carbonate groups, or lactone groups. The amine of formula (I) can be incorporated into the resulting polymer network during crosslinking, or it can act as a catalyst for the crosslinking of the amine-reactive compound through homopolymerization.

[0023] Preferably, the amine-reactive compound is an epoxy resin, a polyisocyanate, a poly(meth)acrylate, a polycarboxylic acid or a carboxylic acid anhydride.

[0024] 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-hydroxynaphth-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).

[0025] 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.

[0026] Other suitable epoxy resins are epoxy resins with a high RCI, especially those resulting from the reaction of bio-based hydroxy-functional raw materials with bio-based epichlorohydrin. Vanillin-based epoxy resins, such as vanillin alcohol diglycidyl ethers or the glycidyl ethers of bisvanillin derivatives, as well as glycerol-based epoxy resins, such as the glycidyl ethers of glycerol or polyglycerol, are particularly preferred.

[0027] Preferably, the epoxy resin is a liquid resin or a mixture containing two or more epoxy liquid resins.

[0028] An "epoxy liquid resin" is a technical polyepoxide with a glass transition temperature below 25 °C.

[0029] If necessary, the resin component also contains portions of solid epoxy resin.

[0030] 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.

[0031] Suitable polyisocyanates are in particular diisocyanates, oligomers or derivatives of diisocyanates or polymers containing isocyanate groups, in particular from the reaction of polyols with diisocyanates.

[0032] Suitable diisocyanates are in particular 1,6-hexamethylene diisocyanate (HDI), 2,2,4- and / or 2,4,4-trimethyl-1,6-hexamethylene diisocyanate (TMDI), 1-methyl-2,4(6)-diisocyanatocyclohexane (H 6 TDI), isophorone diisocyanate (IPDI), perhydro-4(2),4'-diphenylmethane diisocyanate (H 12 MDI), 4(2),4'-diphenylmethane diisocyanate (MDI) or 2,4(6)-toluene diisocyanate.

[0033] Suitable oligomers or derivatives of diisocyanates are, in particular, oligomers or derivatives derived from HDI, IPDI, MDI or TDI, which contain, in particular, uretdione, isocyanurate, iminooxadiazinedione, ester, urea, urethane, biuret, allophanate, carbodiimide, uretonimine and / or oxadiazinetrione groups, in particular HDI biurets, HDI isocyanurates, HDI uretdiones, HDI iminooxadiazinediones, HDI allophanates, IPDI isocyanurates, TDI oligomers or mixed isocyanurates based on TDI / HDI, or forms of MDI that are liquid at room temperature (so-called "modified MDI"), which are mixtures of MDI with MDI derivatives, such as, in particular, MDI carbodiimides or MDI uretonimines or MDI urethanes, as well as MDI homologues or their mixtures with MDI (polymeric MDI or PMDI). In particular, they exhibit an average NCO functionality of 2.1 to 4.0.

[0034] Suitable isocyanate group-containing polymers are in particular derived from polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylate polyols, polybutadiene polyols or polyhydroxy-functional fats and oils with HDI, IPDI, H 12 MDI, MDI or TDI . In particular, the polyols have an average OH functionality of 1.6 to 3. In particular, the polymers have an average molecular weight of 1,000 to 15,000 g / mol. In particular, the polymers have an isocyanate group content of 0.5 to 30% by weight, preferably 1 to 25% by weight, particularly preferably 2 to 20% by weight. In particular, the polymers are prepared with an NCO / OH ratio in the range of 1.5 / 1 to 10 / 1. Optionally, unreacted monomeric diisocyanates were removed from the polymer.

[0035] Suitable poly(meth)acrylates are in particular ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate or polypropylene glycol di(meth)acrylate, in particular with an average molecular weight of 200 to 2,000 g / mol, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa-(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, tris(2-hydroxyethyl)cyanurate tri(meth)acrylate, two- or polyvalent acrylic or methacrylic functional polybutadienes or polyisoprenes or block copolymers thereof, di- or polyvalent polyurethane (meth)acrylates, in particular reaction products of polymers containing isocyanate groups, in particular with an average molecular weight of 500 to 20,000 g / mol,with hydroxy-functional (meth)acrylates such as 2-hydroxyethyl acrylate.

[0036] Suitable polycarboxylic acids are in particular oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, maleic acid, fumaric acid, hexahydrophthalic acid, hexahydroisophthalic acid, methylhexahydrophthalic acid, hexahydroterephthalic acid, dimer fatty acids, 3,6,9-trioxaundecanedioic acid or dicarboxylic acids of higher molecular weight polyethylene glycols, citric acid, phthalic acid, isophthalic acid or terephthalic acid.

[0037] Suitable carboxylic anhydrides are in particular succinic anhydride, maleic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methylphthalic anhydride, trimellitic anhydride, pyromellitic dianhydride or 4,4'-[(isopropylidene)-bis(p-phenyleneoxy)]diphthalic dianhydride.

[0038] The amine-reactive compound is particularly preferably an epoxy resin. As a component of a hardener for epoxy resins, the amine of formula (I) offers particularly advantageous properties.

[0039] Particularly suitable epoxy resins are bisphenol A diglycidyl ether and / or bisphenol F diglycidyl ether, such as those commercially available from Olin, Huntsman, or Momentive. These liquid resins have a low viscosity for epoxy resins and enable rapid curing and high hardness. They can contain portions of bisphenol A solid resin or novolak epoxy resins.

[0040] A bisphenol A diglycidyl ether with an RCI of 0.3 from the reaction of bisphenol A with bio-based epichlorohydrin is particularly preferred. This enables a particularly sustainable epoxy resin composition. Phenol-formaldehyde novolak glycidyl ethers, especially those with an average functionality in the range of 2.3 to 4, preferably 2.5 to 3, are also particularly suitable as epoxy resins. They may contain proportions of other epoxy resins, in particular bisphenol A diglycidyl ether or bisphenol F diglycidyl ether. Vanillin alcohol diglycidyl ethers or the glycidyl ethers of glycerol or polyglycerol, in particular vanillin alcohol diglycidyl ether, are also particularly suitable as epoxy resins.

[0041] Preferably, R 1< represents an alkyl radical having 1 to 6 carbon atoms, especially methyl. Such an amine of formula (I) enables particularly low-viscosity curable compositions.

[0042] Such an amine of formula (I) is preferably prepared starting from vanillin (4-hydroxy-2-methoxybenzaldehyde), in which the free ortho position to the phenol group is alkylated with a formyl group from hexamethylenetetramine in a Duff reaction to give 5-formylvanillin, then the phenol group is alkylated, and finally the resulting dialdehyde of formula (II) is reductively aminated with an amine of formula (III) or hydroxylamine, where R 1< , R 2< and R 3< have the meanings mentioned.

[0043] In a preferred embodiment of the invention, R 2 and R 3 are both H. Such an amine of formula (I) is a primary diamine and particularly suitable as a curing agent. It enables particularly rapid curing and a particularly high final hardness.

[0044] Preferably, R 1< represents methyl and the amine of formula (I) thus represents 1,3-bis(aminomethyl)-4,5-dimethoxybenzene (Ia) or 1,3-bis(aminomethyl)-4,5-dimethoxycyclohexane (Ib).

[0045] Such an amine of formula (I) enables curable compositions with rapid curing and high final hardness, in particular epoxy resin products with a high glass transition temperature.

[0046] 1,3-Bis(aminomethyl)-4,5-dimethoxybenzene (Ia) is liquid at room temperature and enables faster curing with significantly less surface disturbances due to blushing effects when crosslinking epoxy resins compared to the petroleum-based 1,3-bis(aminomethyl)phenol (MXDA).

[0047] 1,3-Bis(aminomethyl)-4,5-dimethoxycyclohexane (Ib) is liquid at room temperature and enables high light stability with low tendency to yellowing and surprisingly fast curing with epoxy resins.

[0048] The amines of formula (Ia) or (Ib) are obtainable in particular from the reductive amination of the corresponding dialdehyde of formula (II) with ammonia or hydroxylamine, the hydrogenation conditions being chosen such that the benzene ring is largely not hydrogenated and the amine of formula (Ia) is formed, or the benzene ring is largely also hydrogenated and the amine of formula (Ib) is formed.

[0049] In a further preferred embodiment of the invention, R 3< is H and R 2< is a monovalent organic radical having 1 to 6 carbon atoms, in particular methyl, ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexyl, benzyl, furfuryl, or tetrahydrofurfuryl. R 1< is preferably methyl. Such an amine of formula (I) enables a particularly long open time, a particularly low exothermicity during curing, and, in the case of an epoxy resin composition, a particularly low tendency toward blushing effects.

[0050] Particularly preferably, R 2< represents furfuryl or tetrahydrofurfuryl and R 3< represents H.

[0051] Preferably, R 1< is methyl. Such an amine of formula (I) is low-viscosity and has a high RCI. It is obtainable in particular from the reductive amination of 4,5-dimethoxyisophthalaldehyde as dialdehyde of formula (II) with furfurylamine, in particular a furfurylamine from a bio-based source, wherein the hydrogenation conditions are selected such that the furan ring is largely not hydrogenated and mainly 1,3-bis(furfurylaminomethyl)-4,5-dimethoxybenzene (Ic) is formed, or the hydrogenation conditions are selected such that the furan ring is largely also hydrogenated, but the benzene ring is not hydrogenated and mainly 1,3-bis(tetrahydrofurfurylaminomethyl)-4,5-dimethoxybenzene (Id) is formed, or the hydrogenation conditions are selected such that the furan ring and the benzene ring are both also hydrogenated and thus mainly 1,3-bis(tetrahydrofurfurylaminomethyl)-4,5-dimethoxycyclohexane (Ie) is formed.

[0052] In the case of the amine of formula (Ic) and / or (Id), the reaction product typically also contains the corresponding mixed hydrogenated amines of formulae

[0053] These preferred amines of formula (I) are, in particular, diamines with primary and / or secondary amino groups. They are particularly suitable as curing agents for the amine-reactive compounds mentioned, either with Benzene ring or cyclohexane ring. The benzene ring typically enables a particularly high final hardness, while the cyclohexane ring provides a particularly low tendency to yellowing.

[0054] The amines of formula (I) described below are particularly suitable as hardeners for epoxy resins as amine-reactive compounds.

[0055] In a preferred embodiment of the invention, R 1< is H and for a benzene ring. Such an amine of formula (I) contains a phenol group. It is also known as a Mannich base and enables particularly rapid curing of epoxy resins.

[0056] It is preferably prepared by reacting guaiacol (2-methoxyphenol), formaldehyde and at least one amine of formula (III) in a Mannich reaction.

[0057] In a preferred embodiment of the invention, R 1< is H, represents a benzene ring and R 2< and R 3< both represent methyl. The amine of formula (I) thus represents 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If).

[0058] This amine is low-viscosity and particularly suitable as a co-curing agent and / or accelerator for the curing of epoxy resins. It enables easy-to-process epoxy resin products with surprisingly fast curing and low odor, especially compared to the well-known petroleum-based accelerator 2,4,6-tris(dimethylaminomethyl)phenol.

[0059] 2,4-Bis(dimethylaminomethyl)-6-methoxyphenol (If) is preferably prepared from the reaction of guaiacol, formaldehyde and dimethylamine in a Mannich reaction.

[0060] It is also possible to prepare the amine of formula (If) from the reductive amination of a dialdehyde of formula (II), in which R 1< is H, with dimethylamine. The hydrogenation is preferably carried out under particularly gentle conditions, particularly at atmospheric pressure and reacted with, for example, sodium borohydride, and the resulting reaction product is preferably purified by distillation.

[0061] Further preferred is an amine of formula (I) in which represents a benzene ring, R 1< represents H, R 2< represents furfuryl and R 3< represents H. The amine of formula (I) thus represents 2,4-bis(furfurylaminomethyl)-6-methoxyphenol (Ig).

[0062] This amine is obtained, in particular, from the reaction of guaiacol, furfurylamine, and formaldehyde, or from the transamination of 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If) with furfurylamine, releasing and removing dimethylamine. The amine of formula (Ig) has, in particular, an RCI of 1 and enables epoxy resin products that cure largely without surface defects caused by blushing.

[0063] In a further preferred embodiment of the invention, R 3< is H and R 2< is a linear aminoalkyl radical having 2 to 6 C atoms, in particular 2-aminoethyl. Such an amine of formula (I) enables a particularly high crosslinking density, particularly high adhesive forces, and high glass transition temperatures. R 1< is preferably methyl.

[0064] Particularly preferably, R 1< is methyl, R 2< is 2-aminoethyl and R 3< is H. The amine of the formula (I) thus represents in particular 1,3-bis(N-(2-aminoethyl)aminomethyl)-4,5-dimethoxybenzene (Ih) or 1,3-bis(N-(2-aminoethyl)aminomethyl)-4,5-dimethoxycyclohexane (Ii).

[0065] The amines of formulas (Ih) or (Ii) are obtained in particular from the reductive amination of 4,5-dimethoxyisophthalaldehyde as the dialdehyde of formula (II) with an excess of 1,2-ethanediamine as the amine of formula (III), followed by removal of unreacted 1,2-ethanediamine. A reaction product thus obtained typically contains higher molecular weight fractions of doubly alkylated 1,2-ethanediamine. If desired, it can be freed from such fractions by distillation.

[0066] Particularly preferred is an amine of formula (Ih) which has been freed from higher molecular weight components by distillation.

[0067] In a further preferred embodiment of the invention, R 3< is H and R 2< is an N-substituted aminoalkyl radical having 2 to 10 C atoms, in particular 2-benzylaminoethyl, 2-furfurylaminoethyl or 3-dimethylaminopropyl.

[0068] Preference is given to represents a benzene ring and R 1< represents H or methyl. Particularly preferred are therefore 2,4-bis((2-furfurylaminoethyl)aminomethyl)-6-methoxyphenol (Ij), 1,3-bis((2-furfurylaminoethyl)aminomethyl)-4,5-dimethoxybenzene (Ik), 2,4-bis((2-benzylaminoethyl)aminomethyl)-6-methoxyphenol (Im), 1,3-bis((2-benzylaminoethyl)aminomethyl)-4,5-dimethoxybenzene (In), 2,4-bis(3-dimethylaminopropylaminomethyl)-6-methoxyphenol (Io) or 1,3-bis(3-dimethylaminopropylaminomethyl)-4,5-dimethoxybenzene (Ip).

[0069] The amines of formulas (Ij), (Im) and (Io) are obtained in particular from the reaction of guaiacol with N-furfuryl-1,2-ethanediamine or N-benzyl-1,2-ethanediamine or 3-dimethylaminopropylamine as amine of formula (III), or from the transamination of 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If) with N-furfuryl-1,2-ethanediamine or N-benzyl-1,2-ethanediamine or 3-dimethylaminopropylamine and removal of dimethylamine.

[0070] The amines of formulas (Ik), (In) and (Ip) are obtained in particular from the reductive amination of 4,5-dimethoxyisophthalaldehyde as dialdehyde of formula (II) with N-furfuryl-1,2-ethanediamine or N-benzyl-1,2-ethanediamine or 3-dimethylaminopropylamine as amine of formula (III).

[0071] In a preferred embodiment of the invention, in the amine of formula (I), the R 2< radicals on the two nitrogen atoms each represent different radicals. Preferably, R 1< is methyl, both R 3< radicals are H, one of the R 2< radicals is H, and the other R 2< radical is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexyl, benzyl, furfuryl, tetrahydrofurfuryl, or 3-dimethylaminopropyl.

[0072] In the case of = benzene ring, the amine of the formula (I) thus represents in particular an amine of the formula (Iq) or (Ir), or an amine of the formula (Is) or (It), or an amine of the formula (Iu) or (Iv), or an amine of the formula (Iw) or (Ix), or an amine of the formula (Iy) or (Iz).

[0073] The amines of formulas (Iq) to (Ix) are suitable as hardeners for all mentioned amine-reactive compounds, while the amines of formulas (Iy) and (Iz) are particularly suitable as hardeners for epoxy resins.

[0074] The amines of formulas (Iq) to (Iz) are obtained in particular from the reductive amination of 4,5-dimethoxyisophthalaldehyde as the dialdehyde of formula (II) with ammonia or hydroxylamine and methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, cyclohexylamine, benzylamine, furfurylamine, or 3-dimethylaminopropylamine as a further amine of formula (III). Such amines enable an interesting combination of long open time with rapid curing and a low tendency toward blushing effects with rapid curing.Typically, they are part of a reaction product which additionally contains the two corresponding symmetrically substituted amines of formula (I), in the case of the amine of formula (Iw) and (Ix) i.e. 1,3-bis(aminomethyl)-4,5-dimethoxybenzene (Ia) and 1,3-bis(furfurylaminomethyl)-4,5-dimethoxybenzene (Ic), and in the case of the amine of formula (Iy) and (Iz) i.e. 1,3-bis(aminomethyl)-4,5-dimethoxybenzene (Ia) and 1,3-bis(3-dimethylaminopropylaminomethyl)-4,5-dimethoxybenzene (Ip).

[0075] As already mentioned, the above-mentioned amines of formula (I) can be prepared in various ways.

[0076] An amine of formula (I) in which R 1< represents an alkyl radical having 1 to 6 C atoms, in particular methyl, is preferably obtained from a process in which (i) in a first step, vanillin is reacted with hexamethylenetetramine and water in the presence of acid to give 5-formylvanillin, (ii) in a second step, 5-formylvanillin is alkylated at the phenol group to give a dialdehyde of formula (II), and (iii) in a third step, the dialdehyde of formula (II) is condensed with at least one amine of formula (III) or hydroxylamine and hydrogenated with hydrogen to give the amine of formula (I).

[0077] The vanillin used in the process is preferably bio-based and has an RCI of 1. It is particularly preferably derived from a lignin degradation process. Such vanillin grades are commercially available, for example, as EuroVanillin Supreme, EuroVanillin Regular, or EuroVanillin Aromatic (from Borregaard).

[0078] In the first step of the process, the vanillin is reacted with hexamethylenetetramine and water in the presence of acid, introducing a formyl group at the free ortho position to the phenol group, thus yielding 5-formylvanillin (4-hydroxy-5-methoxyisophthalaldehyde) (Duff reaction). Sulfuric acid, trifluoroacetic acid, acetic acid, or a mixture of two or more of these acids is preferred as the acid. Hexamethylenetetramine (1,3,5,7-tetraazaadamantane) serves as the source of the formyl group. It is itself obtained from the reaction of formaldehyde and ammonia and is inexpensively available. A grade of hexamethylenetetramine produced from bio-based formaldehyde is preferred. Vanillin and hexamethylenetetramine are preferably used in a molar ratio of approximately 1:1. Vanillin and hexamethylenetetramine are preferably mixed with the acid, optionally in the presence of a suitable solvent.The acid is preferably used to dissolve vanillin and hexamethylenetetramine without the presence of a further organic solvent. The reaction mixture is preferably heated, in particular to a temperature in the range from 80 to 150°C, and after a suitable reaction time, in particular after a few hours, water or an aqueous acid, such as hydrochloric acid, is added and the reaction is continued before the reaction mixture is cooled and a suitable organic solvent, for example dichloromethane, is added to take up the 5-formylvanillin formed in the organic phase and separate it from the other reagents. The solvent of the organic phase is then removed by distillation, and 5-formylvanillin (= dialdehyde of the formula (II) with R 1< = H) is obtained as a crystalline solid. For purification, the resulting solid can be recrystallized, for example from toluene.

[0079] In the second step of the process, 5-formylvanillin is alkylated at the phenol group using a suitable method to obtain a dialdehyde of formula (II) where R 1< = alkyl radical having 1 to 6 C atoms. If a bio-based alkylating agent is used, the resulting dialdehyde in particular continues to have an RCI of 1. Suitable alkylating agents are in particular alkyl halides, carboxylic acids or esters of sulfuric acid, sulfonic acids, phosphoric acid or phosphonic acids, preferably dimethyl sulfate, diethyl sulfate or formic acid. The phenol group is preferably methylated, in particular by reaction with dimethyl sulfate or formic acid. This gives 4,5-dimethoxyisophthalaldehyde (dialdehyde of formula (II) where R 1< = methyl) in particular as a crystalline solid.

[0080] In the third step of the process, the dialdehyde of formula (II) is condensed with at least one amine of formula (III) or hydroxylamine and hydrogenated with hydrogen to form the amine of formula (I). This reaction is also referred to as reductive amination. The intermediate product formed is an imine of formula (IV) or—in the case of hydroxylamine—a dioxime of formula (V). This intermediate can be isolated if desired, or preferably is not isolated and hydrogenated directly with hydrogen to form the amine of formula (I).

[0081] Preferably, at least 2 mol of amine of formula (III) or hydroxylamine are used per mol of dialdehyde of formula (II).

[0082] Hydrogenation can be carried out directly with molecular hydrogen or indirectly by hydrogen or hydride transfer from other reagents, such as formic acid, lithium aluminum hydride, or sodium borohydride. Hydrogenation is preferably carried out with molecular hydrogen.

[0083] The hydrogenation is preferably carried out 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.

[0084] When using molecular hydrogen, hydrogenation is preferably carried out in a pressure apparatus at a hydrogen pressure of 5 to 300 bar. This can be done in a batch process or, preferably, in a continuous process.

[0085] The hydrogenation is preferably carried out at a temperature in the range of 40 to 150 °C.

[0086] The hydrogenation conditions can be chosen so that the aromatic ring is not hydrogenated, whereby an amine of formula (I) with = benzene ring is formed. However, the hydrogenation conditions can also be chosen so that the aromatic ring is also hydrogenated, whereby an amine of formula (I) with = Cyclohexane ring is formed.

[0087] If the aromatic ring is not to be hydrogenated during hydrogenation, it is preferable to operate at a temperature in the range of 60 to 120 °C and a hydrogen pressure in the range of 10 to 120 bar. Otherwise, it is preferable to operate at a temperature in the range of 80 to 150 °C and a hydrogen pressure in the range of 150 to 250 bar.

[0088] Preferably, the volatile components, in particular released water and any solvent present, are removed from the reaction product after hydrogenation, in particular by distillation or stripping.

[0089] Suitable amines of formula (III) are in particular those already mentioned, in particular ammonia, methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, cyclohexylamine, benzylamine, furfurylamine, 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, N-benzyl-1,2-ethanediamine, N-furfuryl-1,2-ethanediamine or 3-dimethylaminopropylamine.

[0090] In the case of ammonia as amine of formula (III), preferably significantly more than 2 mol of ammonia per mol of dialdehyde of formula (II) are converted in a pressure apparatus at a hydrogen pressure of 5 to 300 bar to the amine of formula (I) with R 2< and R 3< = H.

[0091] For laboratory synthesis, hydroxylamine is preferably used instead of ammonia, in particular approximately 2 mol of hydroxylamine per mol of dialdehyde of formula (II).

[0092] In the case of an amine having a primary amino group and no further amine hydrogens as the amine of formula (III), such as methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, cyclohexylamine, benzylamine, furfurylamine or 3-dimethylaminopropylamine, preferably approximately 2 moles of the amine of formula (III) are used per mole of dialdehyde of formula (II).

[0093] In the case of a primary diamine as the amine of formula (III), such as 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, or 1,6-hexanediamine, it is preferable to use more than 2 mol of amine of formula (III) per mol of dialdehyde of formula (II). Preferably, at least 4 mol, in particular 6 to 20 mol, of an amine of formula (III) with R 2< = aminoalkyl radical and R 3< = H are used per mol of dialdehyde of formula (II), and the excess of amine of formula (III) is preferably removed, in particular after hydrogenation, together with the liberated water and any solvent present, in particular by distillation or stripping.

[0094] In the case of a diamine having a primary and a secondary amino group as the amine of formula (III), such as N-benzyl-1,2-ethanediamine or N-furfuryl-1,2-ethanediamine, approximately 2 mol of the amine of formula (III) are preferably used per mole of dialdehyde of formula (II). However, it is also possible to use more than 2 mol of such an amine of formula (III), in particular 2.5 to 10 mol. The excess amine of formula (III) is preferably not removed from the reaction product, and the resulting amine of formula (I) is thus used together with the unreacted amine of formula (III) as a curing agent.

[0095] An amine of formula (I) in which R 1< is H and represent a benzene ring, is preferably prepared by means of a Mannich reaction, wherein guaiacol (2-methoxyphenol) is reacted with formaldehyde and at least one amine of formula (III) with the release of water.

[0096] Guaiacol and the amine of formula (III) are preferably initially charged, and the formaldehyde, optionally in the form of 1,3,5-trioxane or paraformaldehyde, is slowly added, the temperature of the reaction mixture preferably being kept in the range of about 50 to 150°C. Subsequently, the released water and any solvent present are distilled off. Preferably, 2 to 20 mol, in particular 2 to 10 mol, of amine of formula (III) and 2 to 3 mol, preferably approximately 2 mol, of formaldehyde are used per mole of guaiacol. Unreacted amine of formula (III) is optionally removed by distillation together with the released water.

[0097] Formaldehyde from a bio-based source is preferably used.

[0098] Guaiacol from a bio-based source is preferred.

[0099] Suitable amines of formula (III) are those already mentioned, in particular dimethylamine, furfurylamine, 3-dimethylaminopropylamine, N-benzyl-1,2-ethanediamine or N-furfuryl-1,2-ethanediamine.

[0100] Dimethylamine is particularly suitable. It yields the particularly preferred 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If) in high purity.

[0101] Starting from 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If), further amines of the formula (I) in which R 1< is H and represent a benzene ring, can be obtained by transamination, as already mentioned. For transamination, 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If) is treated with the respective amine of formula (III) and heated at a temperature in the range of 80 to 160 °C with distillative removal of dimethylamine. In the process, dimethylamino radicals are replaced by the radical of the amine of formula (III) used. In the case of 3-dimethylaminopropylamine as the amine of formula (III), complete transamination produces 2,4-bis(3-dimethylaminopropylaminomethyl)-6-methoxyphenol (Io).

[0102] Preference is given to using 1 to 10 mol of amine of formula (III) per mole of 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If). Particular preference is given to using 2 to 10 mol, in particular 2 to 5 mol, of amine of formula (III) per mole of 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If). If more than 2 mol of amine of formula (III) are used for the transamination, the reaction product typically contains unreacted amine of formula (III). Such a reaction product has particularly low viscosity and can be used as such for curing epoxy resins. However, it can also be purified by removing unreacted amine of formula (III) by distillation.

[0103] The amine of formula (I) is used as a component of a hardener for crosslinking amine-reactive compounds.

[0104] For crosslinking polyisocyanates, poly(meth)acrylates, polycarboxylic acids or carboxylic acid anhydrides, amines of the formula (I) in which R 3< is H and which thus contain primary and / or secondary amino groups are preferred.

[0105] In the case of polyisocyanates as amine-reactive compounds, urea groups are formed during crosslinking with such amines of formula (I) and the products can be referred to as polyureas or polyurethanes.

[0106] The amine of formula (I) can be used, for example, as a component of a curing agent for crosslinking polyisocyanates, wherein the curing agent additionally contains at least one polyol. The amine of formula (I) can be used in a highly substoichiometric ratio with respect to the isocyanate groups, whereby the amine of formula (I) immediately causes thickening upon mixing of the hardener with the polyisocyanate due to the very rapid crosslinking reaction, whereby the mixed composition very quickly acquires high sag resistance, which is advantageous for certain applications. 1,3-bis(aminomethyl)-4,5-dimethoxybenzene (Ia) or 1,3-bis(aminomethyl)-4,5-dimethoxycyclohexane (Ib) are particularly suitable for this purpose.

[0107] In the case of poly(meth)acrylates as amine-reactive compounds, primary and / or secondary amino groups of such amines of formula (I) add to the activated double bonds by crosslinking.

[0108] In the case of polycarboxylic acids or carboxylic anhydrides as amine-reactive compounds, crosslinking with amines of formula (I) with primary and / or secondary amino groups produces polyamides.

[0109] The amine of formula (I) is particularly preferably used as a component of a hardener for crosslinking epoxy resins.

[0110] The following describes a hardener which is particularly suitable for crosslinking epoxy resins.

[0111] In particular, the hardener may contain more than one amine of formula (I).

[0112] In the case of 2,4-bis(dimethylaminomethyl)-6-methoxyphenol (If) as amine of formula (I), the curing agent preferably contains at least one further amine, which may be another amine of formula (I) or another amine which does not correspond to formula (I).

[0113] An amine of formula (I) in which R 3< is H can be used in the form of an amine-functional adduct with at least one epoxy resin. Adducts with a monoepoxide are preferred, in particular in a ratio of 1 to 10 mol, preferably 1 to 5 mol, of amine of formula (I) per mole of monoepoxide. Particular preference is given to adducts with a polyepoxide, in particular a diepoxide, in particular in a ratio of 1.4 to 10 mol, preferably 1.5 to 5 mol, of amine of formula (I) per mole equivalent of epoxy groups of the polyepoxide.

[0114] Particularly suitable monoepoxides are phenyl glycidyl ether, cresyl glycidyl ether, or tert-butylphenyl glycidyl ether. Particularly suitable polyepoxides are bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, polyoxypropylene glycol diglycidyl ether, polyoxyethylene glycol diglycidyl ether, or phenol-formaldehyde novolak glycidyl ether, especially bisphenol A diglycidyl ether.

[0115] The hardener preferably contains at least one further component selected from further amines which do not correspond to formula (I), accelerators and diluents, in particular at least one further amine which does not correspond to formula (I).

[0116] The curing agent preferably contains at least one further amine which does not correspond to formula (I) and which is not a by-product from the preparation of the amine of formula (I).

[0117] As a further amine which does not correspond to formula (I), preference is given to amines having aliphatic amino groups and at least three amine hydrogens, in particular N-benzyl-1,2-ethanediamine, N-benzyl-1,2-propanediamine, N-benzyl-1,3-bis(aminomethyl)benzene, N-(2-ethylhexyl)-1,3-bis(aminomethyl)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-menthanediamine, 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, especially polyoxypropylenediamines or polyoxypropylenetriamines such as Jeffamine®< D-230, Jeffamine®< D-400 or Jeffamine®< T-403 (all from Huntsman), furan-based amines such as N-furfuryl-1,2-ethanediamine, 2,5-bis(aminomethyl)furan, 2,5-bis(aminomethyl)tetrahydrofuran,Bis(5-aminomethylfuran-2-yl)methane, bis(5-aminomethyltetrahydrofuran-2-yl)methane, 2,2-bis(5-aminomethylfuran-2-yl)propane or 2,2-bis(5-aminomethyltetrahydrofuran-2-yl)propane, or 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, bis(hexamethylene)triamine (BHMT), N-aminoethylpiperazine, 3-dimethylaminopropylamine (DMAPA), 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA), amine-functional adducts of the above-mentioned amines with epoxides, phenalkamines, which are reaction products of cardanol with aldehydes, in particular formaldehyde,and polyamines, or a mixture of two or more of these amines.

[0118] The hardener preferably contains at least one amine selected from the group consisting of N-benzyl-1,2-ethanediamine, N,N'-dibenzyl-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, MXDA, DETA, TETA, TEPA, N3-amine, N4-amine, DPTA, BHMT, polyoxypropylenediamines having an average molecular weight M n in the range from 200 to 500 g / mol, polyoxypropylenetriamines having an average molecular weight M n in the range from 300 to 500 g / mol, N-furfuryl-1,2-ethanediamine, 2,5-bis(aminomethyl)furan, 2,5-bis(aminomethyl)tetrahydrofuran, bis(5-aminomethylfuran-2-yl)methane, bis(5-aminomethyltetrahydrofuran-2-yl)methane, 2,2-bis(5-aminomethylfuran-2-yl)propane, 2,2-bis(5-aminomethyltetrahydrofuran-2-yl)propane and phenalkamines.

[0119] IPDA is preferred. This achieves particularly high glass transition temperatures, enabling particularly good robustness at high service temperatures. IPDA with a high RCI made from bio-based acetone is particularly preferred, allowing for particularly sustainable hardeners.

[0120] Another preferred hardener is N-benzyl-1,2-ethanediamine. This type of hardener enables particularly low-viscosity epoxy resin products with particularly attractive surfaces.

[0121] N-furfuryl-1,2-ethanediamine is still preferred. This hardener is particularly sustainable and enables particularly low-viscosity epoxy resin products with particularly attractive surfaces.

[0122] Further preferred among these are 2,5-bis(aminomethyl)furan, 2,5-bis(aminomethyl)tetrahydrofuran, bis(5-aminomethylfuran-2-yl)methane, bis(5-aminomethyltetrahydrofuran-2-yl)methane, 2,2-bis(5-aminomethylfuran-2-yl)propane, or 2,2-bis(5-aminomethyltetrahydrofuran-2-yl)propane, especially 2,5-bis(aminomethyl)furan. Such hardeners are particularly sustainable.

[0123] In particular, the hardener may contain more than one further amine which does not correspond to formula (I).

[0124] 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.

[0125] 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.

[0126] A hardener containing an amine of formula (If) is preferably free of 2,4,6-tris(dimethylaminomethyl)phenol.

[0127] 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.

[0128] Preferred among these are thinners with a boiling point above 200 °C, especially benzyl alcohol, styrenated phenol, ethoxylated phenol, aromatic hydrocarbon resins containing phenol groups, such as the Novares® types LS 500, LX 200, LA 300, or LA 700 (from Rütgers), diisopropylnaphthalene, or cardanol, especially benzyl alcohol. Phenol-containing thinners also act as accelerators. Also preferred are aromatic thinners with a particularly high diluting effect, especially xylene.

[0129] Of these, thinners with an RCI of 1, especially Cardanol, are particularly preferred. These enable a particularly sustainable hardener.

[0130] The hardener preferably contains only a small amount of thinner, in particular 0 to 50% by weight, preferably 0 to 30% by weight, of thinner based on the total hardener.

[0131] The hardener preferably contains 1 to 99% by weight, more preferably 2 to 90% by weight, more preferably 2 to 80% by weight, particularly preferably 2 to 70% by weight, of amines of the formula (I) based on the total hardener.

[0132] A hardener with amine of formula (If) preferably contains 1 to 80% by weight, particularly preferably 2 to 50% by weight, in particular 2 to 20% by weight, of amine of formula (If) based on the total hardener.

[0133] A hardener with amines of formula (I) in which R 1< is methyl and R 3< is H preferably contains 5 to 90% by weight, in particular 10 to 70% by weight, of amines of formula (I) based on the total hardener.

[0134] The hardener may be water-based and contain water in the range of 15 to 90% by weight, preferably 20 to 80% by weight.

[0135] The hardener is preferably not water-based. It preferably contains less than 15% by weight, in particular less than 10% by weight, of water, based on the total hardener. Such a hardener is particularly suitable for non-aqueous epoxy resin products.

[0136] The hardener may contain other ingredients, in particular: further 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, 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.

[0137] Another object of the invention is an epoxy resin composition comprising a resin component comprising at least one epoxy resin and a hardener component comprising the hardener containing at least one amine of formula (I), as described above.

[0138] Suitable epoxy resins are those already mentioned, in particular bisphenol A diglycidyl ether and / or bisphenol F diglycidyl ether, phenol-formaldehyde novolak glycidyl ether, or in particular epoxy resins with a high RCI such as bisphenol A diglycidyl ether from the reaction of bisphenol A with bio-based epichlorohydrin or in particular vanillin alcohol diglycidyl ether or the glycidyl ethers of glycerol or polyglycerol.

[0139] The resin component may contain a reactive diluent.

[0140] 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.

[0141] The epoxy resin composition preferably contains at least one further component selected from the group consisting of thinners, accelerators, fillers, pigments and surface-active additives.

[0142] The ones already mentioned are particularly suitable as thinners or accelerators.

[0143] 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, micaceous iron oxide, 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, metal powders such as aluminum, copper, iron, zinc, silver, or steel, PVC powder or hollow spheres, as well as bio-based fillers such as lignin powder or nutshells or fruit stones ground into powder. Preferred fillers are calcium carbonate, barite, quartz flour, talc, aluminum powder, bio-based fillers, or a combination thereof.

[0144] Suitable pigments include, in particular, titanium dioxide, iron oxide, chromium(III) oxide, organic pigments, carbon black, or anticorrosive pigments, especially phosphates, orthophosphates, or polyphosphates, which contain, in particular, chromium, zinc, aluminum, calcium, strontium, or a combination of these metals as counterions. Titanium dioxide is particularly suitable.

[0145] Suitable surface-active additives are, in particular, defoamers, deaerators, wetting agents, dispersants, leveling agents and / or dispersed paraffin waxes.

[0146] The epoxy resin composition may contain other auxiliaries 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; Fibers, in particular glass fibers, carbon fibers, metal fibers, ceramic fibers, hemp fibers, cellulose fibers or plastic fibers such as polyamide fibers or polyethylene fibers; 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 stabilizers against oxidation, heat, light or UV radiation or biocides.

[0147] The epoxy resin composition preferably contains only a low content of thinners. It preferably contains less than 20% by weight, more preferably less than 10% by weight, especially less than 5% by weight, and most preferably less than 1% by weight of thinner.

[0148] The epoxy resin composition may contain water.

[0149] In one embodiment, the epoxy resin composition is water-based. The epoxy resin is preferably emulsified in water in an amount of 50 to 85% by weight, and the hardener component preferably contains 20 to 80% by weight of water.

[0150] Preferably, however, the epoxy resin composition contains only a low water content, preferably less than 5% by weight, in particular less than 1% by weight. Such a non-water-based epoxy resin composition is particularly versatile and particularly water-resistant.

[0151] Preferably, an epoxy resin composition comprising a resin component containing at least one epoxy resin and optionally further components such as, in particular, reactive diluents containing epoxy groups, thinners, fillers, pigments and / or surface-active additives, and a hardener component containing at least one amine of the formula (I) and optionally further components such as, in particular, further amines, accelerators and / or thinners.

[0152] The resin and hardener components of the epoxy resin composition are stored in separate containers.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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. Furthermore, a phenol-containing amine of formula (I) catalyzes the homopolymerization of the epoxy groups. As a result primarily of these reactions, the composition polymerizes and thus cures.

[0157] Curing typically takes several hours to days. The duration depends, among other things, on the temperature, the reactivity of the components, their stoichiometry, and the presence or amount of accelerators.

[0158] In the freshly mixed state, the epoxy resin composition preferably has a low viscosity. The viscosity 5 minutes after mixing the resin and hardener components at 20°C is preferably in the range of 0.1 to 50 Pa s, preferably 0.2 to 20 Pa s, particularly preferably 0.3 to 10 Pa s, measured using a cone-and-plate viscometer at a shear rate of 10 s -1< .

[0159] The epoxy resin composition is applied to at least one substrate and / or into at least one casting mold.

[0160] Particularly suitable 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), natural fiber-reinforced plastics (NFRP) 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.

[0161] 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.

[0162] The substrates are in particular coated and / or glued.

[0163] A suitable casting mold is a device into which the mixed, liquid epoxy resin composition can be poured and cured therein and, after curing, can be demolded or removed therefrom, whereby the cured composition forms a molded body.

[0164] The casting mold preferably consists, at least on the surface, of a material from which the cured epoxy resin composition can be removed again without damage, in particular of metal, ceramic, plastic or silicone, which may optionally be provided with a non-stick coating, in particular of Teflon, silicone or a wax.

[0165] Another object of the invention is a cured composition obtained from the described epoxy resin composition after mixing the resin and hardener components.

[0166] 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), GFRP (containing glass fibers), NFRP (containing natural fibers) or wood composite materials, whereby the resulting products are particularly sustainable.

[0167] The use results in an article containing the cured composition of the described epoxy resin composition.

[0168] The article is in particular a floor coating, wall coating, component coating, pipe coating, roof coating or a corrosion protection coating, or a bonded article, or a shaped body, in particular a composite material. Examples

[0169] The following are exemplary embodiments intended to illustrate the described invention in more detail. Of course, the invention is not limited to these described exemplary embodiments.

[0170] "AHEW" stands for amine hydrogen equivalent weight.

[0171] "EEW" stands for epoxy equivalent weight.

[0172] The "standard climate" ("NK") is defined as a temperature of 23±1°C and a relative humidity of 50±5%.

[0173] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH. Description of the measurement methods:

[0174] 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).

[0175] Infrared spectra (FTIR) were measured on undiluted films on a Thermo Scientific Nicolet iS5 FTIR instrument equipped with a horizontal diamond crystal ATR measurement unit. The absorption bands are given in wavenumbers (cm -1< ).

[0176] 1< H and 13< C NMR spectra were measured at room temperature on a Bruker Ascend spectrometer at 400.14 MHz ( 1< H) and 100.63 MHz ( 13< C); chemical shifts δ are given in ppm relative to tetramethylsilane (TMS). Coupling constants J are given in Hz. True and pseudo-coupling patterns were not distinguished.

[0177] The viscosity was measured on a thermostatted cone-plate viscometer Rheotec RC30 (cone diameter 50 mm, cone angle 1°, cone tip-plate distance 0.05 mm, shear rate 10 s -1< ).

[0178] The Amine number was determined by titration (with 0.1 N HClO 4 in acetic acid against crystal violet). Substances and abbreviations used:

[0179] Vanillin EuroVanillin Supreme, RCI = 1 (from Borregaard) Araldite ®< GY 250 Bisphenol A diglycidyl ether, EEW approx. 187 g / eq (from Huntsman) Araldite ®< DY-E Monoglycidyl ether of C 12 to C 14 alcohols, EEW approx. 290 g / eq (from Huntsman) MXDA 1,3-Bis(aminomethyl)benzene, AHEW 34 g / eq (from Mitsubishi Gas Chemical) Dibenzyl-MXDA N,N'-Dibenzyl-1,3-bis(aminomethyl)benzene, AHEW approx. 158.2 g / eq, prepared by reductive alkylation of MXDA and benzaldehyde in a molar ratio of 1:2 Diethylhexyl-MXDA N,N'-Bis(2-ethylhexyl)-1,3-bis(aminomethyl)benzene, AHEW approx. 180.3 g / eq, prepared by reductive alkylation of MXDA and 2-ethylhexanal in a molar ratio of 1:2 B-EDA N-Benzyl-1,2-ethanediamine, AHEW 50.1, prepared by reductive alkylation of 1,2-ethanediamine and benzaldehyde in a molar ratio of 3:1 and subsequent purification by distillation Ancamine ®< K54 2,4,6-Tris(dimethylaminomethyl)phenol (from Evonik) Production of dialdehydes: 4-Hydroxy-5-methoxyisophthalaldehyde (= 5-formylvanillin)

[0180] 100.61 g (0.661 mol) of vanillin (4-hydroxy-3-methoxybenzaldehyde) and 110.96 g (0.791 mol) of hexamethylenetetramine (1,3,5,7-tetraazaadamantane) were placed in a round-bottom flask under a nitrogen atmosphere, and 500 ml of trifluoroacetic acid were added. The reaction mixture was refluxed at approximately 125 °C for 5 h with stirring. 800 ml of aqueous hydrochloric acid (4 M) was then added, and the mixture was refluxed at approximately 125 °C for a further hour. The reaction mixture was then cooled to room temperature and extracted with a total of 600 ml of dichloromethane. The combined organic phase was dried over magnesium sulfate and concentrated using a rotary evaporator. The resulting solid residue was recrystallized from toluene and dried under reduced pressure. 98.15 g (0.54 mol) of a yellowish powder with a purity of > 99% (retention time 11.12 min) determined by GC (in ethyl acetate) were obtained.

[0181] 1< H-NMR (DMSO-d6): 11.30 (br s, 1 H, Ar-OH), 10.36 (s, 1H, O=CH 3 position), 9.89 (s, 1H, O=CH 1 position), 7.88 (d, 1 H, Ar-H, J = 1.8), 7.61 (d, 1 H, Ar-H, J = 1.8), 3.96 (s, 3 H, OCH 3 ).

[0182] 13< C-NMR (CDCl 3 ): 55.46 (OCH 3 ), 113.26 (Ar-CH ), 119.00 (Ar-CH ), 128.08 (Ar-C-CHO 3-position), 128.46 Ar-C-CHO 1-position), 148.42 (Ar-C-OCH 3 ), 156.09 (Ar-C-OH), 188.56 (CHO 3-position), 194.83 (CHO 1-position) FT-IR: 3073, 3032, 2991, 2939, 2873, 2733, 2508, 2559, 1683, 1640, 1615, 1588, 1557, 1538, 1502, 1467, 1453, 1435, 1407, 1385, 1323, 1293, 1276, 1200, 1183, 1145, 1090, 1029, 1015, 982, 956, 908, 883, 830, 809, 797, 763, 732, 666. 4,5-Dimethoxyisophthalaldehyd

[0183] 5.01 g (27.8 mmol) of 4-hydroxy-5-methoxyisophthalaldehyde (prepared as described above) were placed in a round-bottom flask under a nitrogen atmosphere, dissolved in 130 ml of dimethylformamide, treated with 11.53 g of potassium carbonate and 0.46 g of tetrabutylammonium iodide, and stirred at room temperature for 2 h. Subsequently, 8.09 g (55.6 mmol) of dimethyl sulfate were slowly added, and the reaction mixture was stirred at room temperature for 24 h. 40 ml of aqueous sodium hydroxide solution (1 M) was then added, the reaction mixture was concentrated on a rotary evaporator, the resulting solid was dissolved in water, and extracted with 300 ml of ethyl acetate. The combined organic phase was dried over magnesium sulfate, concentrated on a rotary evaporator, and dried in vacuo. 5.61 g (26.7 mmol) of a yellowish powder with a purity of > 99% determined by GC in ethyl acetate (retention time 11.49 min) were obtained.

[0184] 1< H-NMR (CDCl 3 ): 10.38 (s, 1H, O=CH 3 position), 9.87 (s, 1H, O=CH 1 position), 7.86 (d, 1 H, Ar-H, J = 1.92), 7.59 (d, 1 H, Ar-H, J = 1.92), 4.05 (s, 3 H, OCH 3 ), 3.91 (s, 3 H, ALSO 3 ).

[0185] 13< C-NMR (CDCl 3 ): 55.24 (OCH 3 ), 61.35 (OCH 3 ), 113.26 (Ar-CH ), 123.42 (Ar-CH ), 128.42 (Ar-C-CHO 3-position), 131.13 (Ar-C-CHO 1-position), 152.64 (Ar-CO), 156.49 (Ar-CO), 188.02 (CHO 3-position), 189.46 (CHO 1-position).

[0186] FT-IR: 3020, 2954, 2873, 2849, 1682, 1597, 1581, 1516, 1485, 1463, 1428, 1386, 1335, 1284, 1248, 1227, 1190, 1133, 1071, 1009, 982, 934, 891, 873, 786, 764, 751. Preparation of amines of formula (I): Amine A1: 1,3-Bis(aminomethyl)-4,5-dimethoxybenzene

[0187] In a round-bottom flask, 49.22 g (0.6 mol) of sodium acetate and 29.09 g (0.44 mol) of aqueous hydroxylamine (50 wt% in water) were dissolved in 500 ml of water under a nitrogen atmosphere. Subsequently, 38.38 g (0.2 mol) of 4,5-dimethoxyisophthalaldehyde (prepared as described above) were added. The reaction mixture was refluxed for 1.5 h at approximately 110 °C, cooled in an ice bath, and the white precipitate was filtered off, washed with 300 ml of ice-cold water, and dried under vacuum. This gave 35.54 g (0.16 mol) of 4,5-dimethoxyisophthalaldehyde dioxime as a white, crystalline powder. 20 g (0.089 mol) of this were dissolved in a mixture of 100 ml of ethanol and 1,200 ml of 1,4-dioxane in a round-bottom flask and hydrogenated at a hydrogen pressure of 80 bar, a temperature of 80 °C and a flow rate of 5 ml / min on a continuously operating hydrogenation apparatus with a Raney nickel fixed bed catalyst.To monitor the reaction, IR spectroscopy was used to check whether the C=N band at approximately 1665 cm -1 had disappeared. The hydrogenated solution was then concentrated in a rotary evaporator at 65 °C. This yielded 16.12 g (0.086 mol) of a yellowish liquid with an amine number of 519 mg KOH / g, a theoretical AHEW of approximately 49.1 g / eq, an RCI of 0.8, a viscosity at 20 °C of 277 mPa s, and a 1,3-bis(aminomethyl)-4,5-dimethoxybenzene content of approximately 92% (retention time 14.59 min), determined by GC in ethyl acetate.

[0188] 1< H-NMR (DMSO-d6): 6.92 (s, 1 H, Ar-H), 6.90 (s, 1 H, Ar-H), 3.79 (s, 3 H, OCH 3 ), 3.70 (s, 3 H, OCH 3 ), 3.67 (s, 2 H, CH 2 -N), 3.66 (s, 2 H, CH 2 -N), 1.81 (br s, 4 H, 2x NH 2 ).

[0189] 13<C-NMR (DMSO-d6): 41.04 (CH 2 -N), 46.22 (CH 2 -N), 56.00 (OCH 3 ), 60.48 (OCH 3 ), 110.32 (Ar-CH), 119.02 (Ar-CH), 137.31 (Ar-C-CH 2 ), 140.33 (Ar-C-CH 2 ), 144.89 (Ar-CO), 152.30 (Ar-CO).

[0190] FT-IR: 3367, 3284, 3189, 2994, 2932, 2831, 1588, 1488, 1462, 1428, 1383, 1338, 1309, 1225, 1185, 1139, 1080, 1051, 1005, 838, 775, 741, 706. Amine A2: 1,3-Bis(furfurylaminomethyl)-4,5-dimethoxybenzol

[0191] In a round-bottom flask, 10.0 g (51.5 mmol) of 4,5-dimethoxyisophthalaldehyde (prepared as described above) were dissolved in 400 ml of isopropyl alcohol. 10.5 g (10.8 mmol) of furfurylamine were slowly added while stirring, and the mixture was stirred for a further 30 min at room temperature. The reaction mixture was then hydrogenated at a hydrogen pressure of 70 bar, a temperature of 70 °C, and a flow rate of 5 ml / min on a continuously operating hydrogenation apparatus with a Raney nickel fixed-bed catalyst. IR spectroscopy was used to monitor the reaction to determine whether the C=N band at approximately 1665 cm -1 had disappeared. The hydrogenated solution was then concentrated on a rotary evaporator at 65 °C. This gave 16.4 g of a clear, yellow liquid with an amine number of 297 mg KOH / g, a theoretical AHEW of about 178.2 g / eq, an RCI of 0.9, a viscosity at 20 °C of 910 mPa s and a content of 1,3-bis(furfurylaminomethyl)-4,5-dimethoxybenzene of about 100 mg KOH / g, determined by GC.88.4% (retention time 18.96 min) and approx. 11.6% by-product (retention time 19.26 min).

[0192] FT-IR: 3324, 2935, 2867, 2834, 1589, 1488, 1455, 1428, 1359, 1310, 1227, 1180, 1145, 1067, 1008, 919, 847, 776. Amine A3: 2,4-Bis(dimethylaminomethyl)-6-methoxyphenol

[0193] 10 g (55 mmol) of 4-hydroxy-5-methoxyisophthalaldehyde (= 5-formylvanillin, prepared as described above), 60 g (120 mmol) of dimethylamine solution (2M in tetrahydrofuran), and 150 ml of tetrahydrofuran were placed in a round-bottomed flask and cooled with ice-water. An orange-red color developed. 35 g of sodium triacetoxyborohydride were then added, and the reaction mixture was stirred for 1 h with ice-water cooling, then for 1 h at room temperature, and finally for 1 h at 40 °C, after which the reaction mixture developed a yellowish color. 75 ml of a potassium carbonate solution (15 wt% in water) was then added to the reaction mixture, and the mixture was stirred at room temperature for 30 min, after which the reaction mixture became almost colorless. The reaction mixture was then concentrated on a rotary evaporator at 80 °C, the residue was taken up in tetrahydrofuran, the undissolved potassium carbonate was filtered off, and the filtrate was concentrated on a rotary evaporator at 65 °C. 12 were obtained.4 g of an orange oil, which was distilled in vacuo at 107 to 120 °C and 250 mbar, yielding 7.5 g of a yellowish oil with an amine number of 467 mg KOH / g.

[0194] 1< H-NMR (CDCl 3 ): 6.77 (d, 1 H, Ar-H), 6.52 (d, 1 H, Ar-H), 3.87 (t, 3 H, OCH 3 ), 3.62 (t, 2 H, CH 2 N), 3.32 (t, 2 H, CH 2 N), 2.32 (t, 6 H, (CH 3 ) 2 N), 2.23 (t, 6 H, (CH 3 ) 2 N). Amine A4: Amine mixture containing 2,4-bis(dimethylaminomethyl)-6-methoxyphenol

[0195] A round-bottomed flask was charged with 24.83 g (0.2 mol) of guaiacol and 81.96 g (0.6 mol) of dimethylamine solution (33 wt% in ethanol) in 250 ml of ethanol, and 18.20 g (0.6 mol) of paraformaldehyde were added. The reaction mixture was heated to reflux for 10 h, then freed of volatile components in a rotary evaporator at 65 °C under vacuum. The mixture was then distilled under vacuum at 120 °C, collecting 25.6 g of distillate at a vapor temperature of approximately 100 °C and 0.005 bar. 45.3 g of distillate was obtained as a yellowish-clear liquid with an amine number of 452 mg KOH / g. According to 1< H-NMR, the content of 2,4-bis(dimethylaminomethyl)-6-methoxyphenol was approximately 89% and the main by-product was 2(4)-dimethylaminomethyl-6-methoxyphenol.

[0196] 1< H-NMR (CDCl 3 ): 6.75 (d, 1 H, Ar-H), 6.57 (d, 1 H, Ar-H), 3.74 (s, 3 H, OCH 3 ), 3.53 (s, 2 H, CH 2 N), 3.24 (s, 2 H, CH 2 N), 2.21 (s, 6H, (CH 3 ) 2 N), 2.11 (2, 6H, (CH 3 ) 2 N). Production of epoxy resin adhesives: Examples 1 and 2:

[0197] Sikadur ®< -42 HE component A (reactively diluted bisphenol A diglycidyl ether, EEW 175.5 g / eq, from Sika) was used as the resin component in the amount (in parts by weight) specified in Table 1.

[0198] The amine listed in Table 1 was used as the hardener component in the specified amount (in parts by weight).

[0199] The two components for each sample were then mixed using a centrifugal mixer (SpeedMixer ™< DAC 150, FlackTek Inc.) and immediately tested as follows: The viscosity was measured 5 minutes after mixing the resin and hardener components as described at a temperature of 20 °C. The Setting timewas determined by tapping the surface of a freshly mixed amount of approximately 3 g in standard conditions with an LDPE pipette at regular intervals until no residue remained on the pipette for the first time.

[0200] The mechanical properties were determined by applying the mixed adhesive to dumbbell-shaped bars with a thickness of 2 mm, a length of 75 mm, a bar length of 30 mm, and a bar width of 4 mm in a silicone mold under standard conditions and curing. The tensile bars were removed from the mold after 1 day under standard conditions and, after a total of 7 days of curing under standard conditions, Tensile strength, elongation at break and that Young's modulus (0.05-0.25% elongation) according to EN ISO 527 at a tensile speed of 10 mm / min. These results are to be interpreted with the addition "NK"Further tensile specimens were removed from the mold after 1 day in standard climate, then post-cured for 1 day in a circulating air oven at 120 °C and stored for 1 day in standard climate before the mechanical properties were determined. These results are marked with the addition "120°C" Further tensile specimens were removed from the mold after 1 day in standard conditions, then post-cured for 1 day in a convection oven at 120 °C, then stored in water at room temperature for 5 days, then dabbed with a hygienic wipe and stored for 1 day in standard conditions before the mechanical properties were determined. These results are marked with the suffix " H2O ".

[0201] The Tg value (glass transition temperature) was determined using DMTA measurements on cylindrical samples (2 mm height, 10 mm diameter), stored as described for tensile strength, using a Mettler DMA / SDTA 861e instrument, measured in shear mode with an excitation frequency of 10 Hz and a heating rate of 5 K / min. The samples were cooled to -70 °C and heated to 200 °C to determine the complex elastic modulus M* [MPa]. A maximum in the curve for the loss angle "tan δ" was read off as the Tg value.

[0202] The results are shown in Table 1.

[0203] Comparative examples are "(Ref.)" designated. 1 2. Table 1: Composition and properties of the examples and Example 1 2 (Ref.) Resin component: Sikadur ®< -42 HE component A 175.5 175.5 Hardener component: With A1 1< 49.1 - MXDA - 34.0 Viscosity (5') [Pa s] 1.47 0.74 Setting time 1.5 h > 4 h Tensile strength [MPa] NK 46.7 58.1 120°C 72.9 68.0 H2O 66.0 66.3 Elongation at break NK 1.6 2.3 120°C 7.7 6.8 H2O 6.2 6.1 Young's modulus [MPa] NK 3320 3160 120°C 3120 2995 H2O 2980 3070 Tg [°C] NK 62 58 120°C 88 84 H2O 82 82 1< manufactured as previously described Production of epoxy resin coatings: Examples 3 to 10:

[0204] For each example, the resin component ingredients listed in Tables 2 and 3 were mixed in the specified amounts (in parts by weight) using a centrifugal mixer and stored under exclusion of moisture.

[0205] Likewise, the ingredients of the hardener component listed in Tables 2 and 3 were processed and stored.

[0206] The two components for each sample were then mixed using the centrifugal mixer and immediately tested as follows: The viscosity and the Setting time were determined as described for Example 1. 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 and after 2 days.

[0207] Furthermore, a film with a layer 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 d, 2 d, 7 d and after 14 d ( 1d NK ), ( 2d NK ), ( 7d NK ), ( 14d NK After 14 days the aspect ( NK ) of the film. A clear film with a glossy and non-sticky surface without any texture was considered "beautiful." "Texture" refers to any type of pattern or design on the surface.

[0208] Another film was applied to a glass plate with a layer thickness of 500 µm. Immediately after application, this film was stored for 7 days at 8 °C and 80% relative humidity and then cured for 2 weeks under standard conditions. 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 on a new part of 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%)" (referred to as "Spotlight") in the same way as described for the aspect (NK). The number and type of visible marks that had been created in the film by the wet sponge were also indicated. "Brands"The number of white spots was indicated. A faint, white spot was designated as "(1)". A distinct, white spot was designated as "1". The hardness of the cured films was again determined after 7 days at 8 °C and 80% relative humidity ( Royal (7d 8° / 80%) ), then after another 2 days in NK ( Royal H. (+2d NK) ) or 7 days in NK ( Royal H. (+7d NK) ) or 14d in NK ( Royal Court (+14d NK) ).

[0209] The results are shown in Tables 2 and 3.

[0210] Comparative examples are "(Ref.)" designated. 3 7. Table 2: Composition and properties of the examples up to Example 3 (Ref.) 4 5 5a 6 (Ref.) 7 (Ref.) Resin component: Araldite ®< GY-250 167.2 167.2 167.2 167.2 167.2 167.2 Araldite ®< DY-E 31.8 31.8 31.8 31.8 31.8 31.8 Hardener component: MXDA 34.0 - - - - With A1 1< - 49.1 - - - With A3 1< - - 2.0 - - With A4 1< - - - 2.0 - B-EDA - - 50.1 50.1 50.1 50.1 Ancamine ®< K54 - - - - 2.0 - Viscosity (5') [Pa s] nb nb 0.24 0.22 0.22 0.23 Setting time nb nb 5 h 5 h 5 h 5 h Shore D (1d NK) nb nb 72 78 68 60 (2d NK) 77 79 71 62 Shore D (1d 8° / 80%) nb nb nm 2< nm 2< nm 2< nm 2< (2d 8° / 80%) 55 58 76 79 King's hardness [s] (1d NK) 11 74 164 91 116 52 (2d NK) 13 148 183 141 157 131 (7d NK) 16 167 190 188 206 142 (14d NK) 22 167 205 190 208 145 Aspect (NK) cloudy, slightly sticky light structure nice nice nice nice Royal St. [s] (7d 8° / 80%) nm 3< 39 45 36 55 31 (+2d NK) nb nb 134 99 101 63 (+7d NK) nb nb 188 145 143 123 (+14d NK) nm 3< 76 188 147 174 169 Aspect (8° / 80%) cloudy, sticky slightly cloudy nice nice nice nice Brands 4 4 (1) (1) (1) (1) 1< manufactured as described above 2< not measurable (too soft) 3< not measurable (sticky) "nb" stands for "not determined" 8 10. Table 3: Composition and properties of the examples up to Example 8 9 (Ref.) 10 (Ref.) Resin component: Araldite ®< GY-250 187.0 187.0 187.0 Hardener component: With A2 1< 178.2 - - Dibenzyl-MXDA - 158.2 - Diethylhexyl-MXDA - - 180.3 Viscosity (5') [Pa s] 4.3 1.2 0.2 Shore D (1d NK) nm 2< nm 2< nm 2< (2d NK) 50 nm 3< nm 2< 1< manufactured as described above 2< too soft 3< too brittle / fragile Production of polyurethane adhesives with high stability during application: Examples 11 to 13:

[0211] For each example, the ingredients of the polyol component listed in Table 4 were mixed in the specified amounts (in parts by weight) using a centrifugal mixer and stored in an atmosphere protected from moisture. The ingredients of the isocyanate component listed in Table 4 were also processed and stored.

[0212] The two components for each example were then mixed using the centrifugal mixer and immediately the StabilityFor this purpose, 8 ml of the freshly mixed compound was applied from a commercially available 10 ml plastic syringe, cut open at the front, onto a piece of horizontally positioned cardboard. The cardboard box containing the applied compound was immediately tilted vertically so that the applied compound was positioned horizontally at the front (nose). Subsequently, the extent of sagging from the horizontal position downwards during curing under standard conditions was assessed. Very slight sagging was designated "very good," while severe sagging was designated "poor."

[0213] The results are shown in Table 4.

[0214] Comparative examples are "(Ref.)" designated. 11 13. Table 4: Composition and properties of the examples up to Example 11 12 (Ref.) 13 (Ref.) Polyol component: Voranol ®< CP 4755 1< 52.2 52.2 52.2 1,4-Butanediol 7.4 7.4 8.4 Amine A1 2.0 - - MXDA - 2.0 - calcined kaolin 2< 33.3 33.3 33.3 Molecular sieve 3Å 4.9 4.9 4.9 DABCO ®< 33 LV 3< 0.2 0.2 0.2 Isocyanate component: Desmodur ®< CD-L 4< 32.3 32.3 32.3 Polymer-1 5< 46.2 46.2 46.2 fumed silica 6< 3.3 3.3 3.3 Stability very good very good bad 1< EO-capped polyoxypropylenetriol, OH number 34.7 mg KOH / g (Dow) 2< Satintone ®< W (from BASF) 3< 33 wt.% 1,4-diazabicyclo[2.2.2]octane in dipropylene glycol (from Evonik) 4< Carbodiimide-modified diphenylmethane diisocyanate, NCO content 29.5 wt.% (from Covestro) 5< NCO content 2.07 wt.% prepared as described below 6< Aerosil ®< 200 (from Evonik)

[0215] The Polymer-1 was prepared by reacting 1,300 g of polyoxypropylenediol (Acclaim ®< 4200 N, OH number 28.5 mg KOH / g, from Covestro), 2,600 g of EO-capped polyoxypropylenetriol (Voranol ®< CP 4755, OH number 34.7 mg KOH / g, from Dow), 600 g of 4,4'-diphenylmethane diisocyanate (Desmodur ®< 44 MC L, from Covestro) and 500 g of diisodecyl phthalate according to a known process at 80 °C to form a polymer containing isocyanate groups and having an NCO content of 2.07% by weight.

Claims

1. Use of a hardener containing at least one amine of formula (I) for crosslinking of amine-reactive compounds, where is a benzene ring or cyclohexane ring, R1 is H or an alkyl radical having 1 to 6 carbon atoms, R2 is H or a monovalent organic radical having 1 to 6 carbon atoms or an aminoalkyl radical having 2 to 10 carbon atoms or an N-substituted aminoalkyl radical having 2 to 10 carbon atoms and R3 is H or methyl.

2. Use according to Claim 1, characterized in that the amine-reactive compound is an epoxy resin, polyisocyanate, poly(meth)acrylate, a polycarboxylic acid or a carboxylic anhydride.

3. Use according to either of Claims 1 and 2, characterized in that the amine-reactive compound is an epoxy resin.

4. Use according to any of Claims 1 to 3, characterized in that R1 is methyl.

5. Use according to Claim 4, characterized in that R2 and R3 are both H.

6. Use according to Claim 4, characterized in that R3 is H and R2 is a monovalent organic radical having 1 to 6 carbon atoms, in particular methyl, ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexyl, benzyl, furfuryl or tetrahydrofurfuryl.

7. Use according to Claim 6, characterized in that R2 is furfuryl or tetrahydrofuryl.

8. Use according to any of Claims 1 to 3, characterized in that R1 is H and is a benzene ring.

9. Use according to Claim 8, characterized in that R2 and R3 are both methyl.

10. Use according to Claim 8, characterized in that R2 is furfuryl and R3 is H.

11. Use according to any of Claims 1 to 3, characterized in that R3 is H and R2 is a linear aminoalkyl radical having 2 to 6 carbon atoms, in particular 2-aminoethyl.

12. Use according to any of Claims 1 to 3, characterized in that R3 is H and R2 is an N-substituted aminoalkyl radical having 2 to 10 carbon atoms, in particular 2-benzylaminoethyl, 2-furfurylaminoethyl or 3-dimethylaminopropyl.

13. Use according to any of Claims 1 to 4, characterized in that in the amine of formula (I) the radicals R2 on the two nitrogen atoms are in each case different radicals.

14. Use according to Claim 3, characterized in that the hardener contains at least one further constituent selected from further amines not conforming to formula (I), accelerators and diluents, in particular at least one further amine not conforming to formula (I).

15. Epoxy resin composition comprising - a resin component comprising at least one epoxy resin and - a hardener component comprising the hardener as described in any of Claims 4 to 14.

16. Cured epoxy resin composition obtained from the epoxy resin composition according to Claim 15 after the mixing of the resin component and the hardener component.