Hardener for epoxy resin coatings

Abstract

The present invention relates to a curing agent for epoxy resins, which contains 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzyl-1,2-ethanediamine in an amount with an amine hydrogen number ratio ranging from 90 / 10 to 20 / 80. The curing agent according to the present invention makes it possible to obtain a suitable epoxy resin composition that has excellent application properties and cures particularly quickly under low temperature and humid conditions without surface defects induced by blushing, thus achieving coatings with particularly high hardness, high glass transition temperature, and unexpectedly low yellowing tendency.

Description

[Technical Field]

[0001] The present invention relates to a curing agent for epoxy resin compositions that are particularly suitable as coatings, especially for floors. [Background technology]

[0002] Epoxy resin-based coatings are widely used in the construction industry. They consist of a liquid resin and a hardener component, which are mixed before application and cure at ambient temperatures ranging from approximately 5 to 35°C. When applied, the coating's viscosity should be as low as possible so that it flows well at ambient temperatures. After application, they should cure as quickly and smoothly as possible, even under humid, cold conditions, to form a defect-free surface without haze, spots, or craters. Once cured, they should have high hardness combined with low brittleness and a high glass transition temperature to withstand mechanical stress as well as possible. For visually demanding applications, such as floor coverings, they should also have a high level of gloss and minimal tendency to yellow under the influence of light.

[0003] However, such epoxy resin coatings are often prone to surface defects such as haze, spots, roughness, or stickiness, also known as "fogging." Fogging is caused by the amines present in the curing agent component forming salts with carbon dioxide from the air, particularly at high humidity and low temperatures. Many curing agents for epoxy resin coatings contain adducts of diamines and epoxy resins, which reduces the fogging effect and also allows for faster curing. However, diamine-epoxy resin adducts have significantly higher viscosities than free diamines, which often means that such curing agents contain significant amounts of thinner and / or can only be moderately loaded with inorganic fillers. The thinner is not incorporated into the resin matrix during curing and can be released into the environment through evaporation or diffusion processes. Recently, however, there has been an increasing demand for low-emission products with a low content of releasable substances after curing. For low-emission or no-emission epoxy resin compositions, this type of thinner is therefore used only in small amounts or not at all.

[0004] EP 3 344 677 discloses epoxy resin compositions containing N-benzylethane-1,2-diamine as a curing agent, which allow coatings with good surfaces to be produced. The coatings contain either diamine-epoxy resin adducts, which greatly increase their viscosity, or polyoxypropylenediamines, which result in coatings with undesirably low glass transition temperatures. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object of the present invention to provide a hardener for epoxy resins that allows for very low viscosity, easily processable epoxy resin compositions with fast cure, high final hardness, and high glass transition temperature with little or no thinner, and that is suitable for coatings that result in defect-free, glossy surfaces even under humid and cold ambient temperatures. [Means for solving the problem]

[0006] This object is achieved by the curing agent described in claim 1. This curing agent contains 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (IPDA) and N-benzylethane-1,2-diamine in amounts such that the ratio of the number of amine hydrogens therein is within the range of 70 / 30 to 20 / 80. In the ratio according to the invention, the curing agent allows for the advantageous combination of a high glass transition temperature, high final hardness, a good surface, and fast curing under low temperature conditions. A higher content of IPDA results in slow curing under low temperature conditions, an undesirably dull surface, and increased yellowing tendency, while a higher content of N-benzylethane-1,2-diamine results in an undesirably low glass transition temperature and final strength.

[0007] Surprisingly, coatings containing the curing agents of the invention exhibit a particularly low tendency to yellow under the influence of light.

[0008] The curing agents of the present invention enable epoxy resin compositions suitable as coatings having excellent processability and fast cure, and having a low tendency to blush-related defects even under humid and low temperature conditions, and having, after cure, high hardness, high glass transition temperature, and unexpectedly low tendency to yellowing.

[0009] 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. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention provides a curing agent for epoxy resins, which contains 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (IPDA) in free form and / or in the form of an adduct with an epoxy resin, and N-benzylethane-1,2-diamine in amounts such that the ratio of the numbers of amine hydrogen atoms therein is within the range of 90 / 10 to 20 / 80.

[0011] A "primary amino group" refers to an amino group that is bonded to only one organic group and has two hydrogen atoms; a "secondary amino group" refers to an amino group that is bonded to two organic groups that may together be part of a ring and has one hydrogen atom; and a "tertiary amino group" refers to an amino group that is bonded to three organic groups, two or three of which may also be part of one or more rings, and does not have any hydrogen atoms.

[0012] "Amine hydrogen" refers to the hydrogen atoms of primary and secondary amino groups.

[0013] "Amine hydrogen equivalent" refers to the mass of an amine or amine-containing composition that contains one molar equivalent of an amine hydrogen. It is expressed in units of "g / equivalent."

[0014] "Epoxide equivalent" refers to the mass of an epoxy group-containing compound or composition that contains one molar equivalent of epoxy groups. It is expressed in units of "g / equivalent."

[0015] Substance names beginning with "poly", such as polyamine or polyepoxide, refer to substances that formally contain two or more of the functional groups appearing in their names per molecule.

[0016] "Thinner" refers to a substance that is soluble in epoxy resin, reduces its viscosity, and does not become chemically incorporated into the epoxy resin polymer during the curing process.

[0017] "Molecular weight" refers to the molar mass of a molecule (in grams per molecule).

[0018] "Average molecular weight" refers to the number average molecular weight M of a polydisperse mixture of oligomeric or polymeric molecules. n and is typically measured by gel permeation chromatography (GPC) against polystyrene as a standard.

[0019] "Gel time" is the time interval from mixing the components of an epoxy resin composition to its gelation.

[0020] "Room temperature" refers to a temperature of 23°C.

[0021] The IPDA present in the hardener is preferably used in commercially available qualities, for example in the form of Vestamin® IPD (Evonik) or Baxxodur® EC 201 (BASF).

[0022] The IPDA present in the curing agent is preferably in free form and does not form adducts with the epoxy resin. The curing agent preferably contains less than 10% by weight, more preferably less than 5% by weight, and especially less than 1% by weight of IPDA adducted with the epoxy resin. Most preferably, the curing agent does not contain IPDA adducted with the epoxy resin. Such curing agents are particularly low in viscosity.

[0023] The N-benzylethane-1,2-diamine present in the curing agent preferably has a purity of at least 80% by weight, more preferably at least 90% by weight, and especially at least 95% by weight. N,N'-dibenzylethane-1,2-diamine is optionally present as well. Preferably, less than 2% by weight, especially less than 1% by weight, of ethane-1,2-diamine is present.

[0024] The N-benzylethane-1,2-diamine present in the curing agent is preferably in free form and does not form an adduct with the epoxy resin. The curing agent preferably contains less than 10% by weight, more preferably less than 5% by weight, and especially less than 1% by weight of N-benzylethane-1,2-diamine adducted with the epoxy resin. Most preferably, the curing agent does not contain N-benzylethane-1,2-diamine adducted with the epoxy resin. Such a curing agent has a particularly low viscosity.

[0025] N-benzylethane-1,2-diamine is preferably prepared by partial alkylation of ethane-1,2-diamine with at least one benzylating agent.

[0026] The alkylation is preferably a reductive alkylation using benzaldehyde as the benzylation agent and hydrogen.

[0027] The reductive alkylation is preferably carried out in the presence of a suitable catalyst, preferred catalysts being palladium on charcoal (Pd / C), platinum on charcoal (Pt / C), Adams' catalyst or Raney nickel, especially palladium on charcoal or Raney nickel.

[0028] If molecular hydrogen is used, the reductive alkylation is preferably carried out in a pressure apparatus at a hydrogen pressure of 5 to 150 bar, in particular 10 to 100 bar. It can be carried out in a batchwise or, preferably, continuous process.

[0029] The reductive alkylation is preferably carried out at a temperature in the range of 40 to 120°C, especially 60 to 100°C.

[0030] Preferably, ethane-1,2-diamine is used in stoichiometric excess relative to the benzaldehyde, and after alkylation, some or all of the unreacted ethane-1,2-diamine is removed from the reaction mixture, especially by stripping.

[0031] If necessary, the reaction mixture can then be further purified, more specifically by removing at least some of the N,N'-dibenzylethane-1,2-diamine from the resulting N-benzylethane-1,2-diamine by distillation, which allows for a particularly highly reactive curing agent and an epoxy resin composition with a particularly high glass transition temperature.

[0032] The ratio of the numbers of amine hydrogens from IPDA and N-benzylethane-1,2-diamine is preferably within the range of 80 / 20 to 25 / 75, particularly 75 / 25 to 30 / 70. Such a curing agent enables epoxy resin compositions to have a particularly good combination of fast curing, high hardness, high glass transition temperature, and good surface.

[0033] The ratio of the numbers of amine hydrogens from IPDA and N-benzylethane-1,2-diamine is particularly preferably in the range of 80 / 20 to 30 / 70, in particular 70 / 30 to 50 / 50. Such hardeners allow for particularly high glass transition temperatures together with good surfaces.

[0034] Furthermore, a ratio of the number of amine hydrogens from IPDA and N-benzylethane-1,2-diamine in the range of 70 / 30 to 20 / 80 is particularly preferred. Such a curing agent allows particularly fast curing under low temperature conditions within 24 hours.

[0035] The curing agent of the present invention preferably comprises at least one further component selected from the group consisting of a further amine, a cure accelerator, and a reducer.

[0036] Suitable further amines are, inter alia, N-benzylpropane-1,2-diamine, N-benzyl-1,3-bis(aminomethyl)benzene, N-(2-ethylhexyl)-1,3-bis(aminomethyl)benzene or N-(2-phenylethyl)-1,3-bis(aminomethyl)benzene, 2,2-dimethylpropane-1,3-diamine, pentane-1,3-diamine (DAMP), pentane-1,5-diamine, 1,5-diamino-2-methylpentane (MPMD), 2-butyl-2-ethylpentane-1,5-diamine (C11-neodiamine), hexane-1,6-diamine, 2,5-dimethylhexane-1,6-diamine, 2,2(4),4-trimethylhexane-1,6-diamine (TMD), heptane-1,7-diamine, octane-1,8-diamine, nonane-1,9- Diamine, decane-1,10-diamine, undecane-1,11-diamine, dodecane-1,12-diamine, 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, 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]heptane 2.6]decane, 1,4-diamino-2,2,6-trimethylcyclohexane (TMCDA), menthane-1,8-diamine, 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)polytetrahydrofuran or other polytetrahydrofuran diamines, polyoxyalkylene diamines or triamines, especially polyoxypropylene diamines or polyoxypropylene triamines, such as Jeffamine® D-230, Jeffamine® D-400 or Jeffamine® T-403 (all from Huntsman), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), dipropylenetriamine (DPTA), N-(2-aminoethyl)propane-1,3-diamine (N3 -amine), N,N'-bis(3-aminopropyl)ethylenediamine (N4-amine), N,N'-bis(3-aminopropyl)-1,4-diaminobutane, N5-(3-aminopropyl)-2-methylpentane-1,5-diamine, N3-(3-aminopentyl)pentane-1,3-diamine, N5-(3-amino-1-ethylpropyl)-2-methylpentane-1,5-diamine, N,N'-bis(3-amino-1-ethylpropyl)-2-methylpentane-1,5-diamines, 3-(2-aminoethyl)aminopropylamine, bis(hexamethylene)triamine (BHMT), N-aminoethylpiperazine, 3-dimethylaminopropylamine (DMAPA) or 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA), as well as further adducts of these polyamines with epoxy resins or monoepoxides, or adducts of ethane-1,2-diamine or propane-1,2-diamine with epoxy resins or monoepoxides, with subsequent removal of excess ethane-1,2-diamine or propane-1,2-diamine by distillation.

[0037] It may be advantageous if the curing agent of the present invention comprises a combination of two or more additional amines.

[0038] TMD, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, 2(4)-methyl-1,3-diaminocyclohexane, MXDA, average molecular weight M in the range of 200–500 g / mol n Polyoxypropylenediamine having an average molecular weight M in the range of 300 to 500 g / mol n Preference is given to further amines selected from the group consisting of polyoxypropylenetriamines having the formula: DMAPAPA, BHMT, DETA, TETA, TEPA, PEHA, DPTA, N3-amines, N4-amines; adducts of MXDA, DETA, TETA or TEPA with epoxy resins, and adducts of MPMD, ethane-1,2-diamine or propane-1,2-diamine with cresyl glycidyl ether (wherein unreacted MPMD, ethane-1,2-diamine or propane-1,2-diamine has been removed by distillation after the reaction).

[0039] Among these, 1,2-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 2(4)-methyl-1,3-diaminocyclohexane, MXDA, and average molecular weight M in the range of 200–500 g / mol are n and a polyoxypropylenediamine having an average molecular weight M in the range of 300 to 500 g / mol. n Preferred is a polyoxypropylene triamine having the formula:

[0040] Particularly preferred is 1,3-bis(aminomethyl)cyclohexane or MXDA, especially 1,3-bis(aminomethyl)cyclohexane. These amines allow for particularly fast curing.

[0041] Furthermore, polyoxypropylene diamines or polyoxypropylene triamines are particularly preferred, as these allow for particularly low brittleness.

[0042] Suitable hardening accelerators are, inter alia, acids or compounds hydrolyzable to acids, especially organic carboxylic acids such as acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid, lactic acid, etc., 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, in particular calcium nitrate; tertiary amines, such as, in particular, 1,4-diazabicyclo[2.2.2]octane, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminopropylamine, imidazoles, 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, phenolic resins or Mannich bases, such as, in particular, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol or phenol, polymers prepared from formaldehyde and N,N-dimethylpropane-1,3-diamine, phosphites, such as, in particular, di- or triphenylphosphite, or compounds containing a mercapto group.

[0043] Acids, nitrates, tertiary amines or Mannich bases, especially salicylic acid, calcium nitrate or 2,4,6-tris(dimethylaminomethyl)phenol, or combinations of these accelerators are preferred.

[0044] The curing agent particularly preferably comprises salicylic acid in an amount ranging from 1 to 15 parts by weight, preferably from 2 to 12 parts by weight, and more preferably from 3 to 10 parts by weight, per 100 parts by weight of the total of IPDA and N-benzylethane-1,2-diamine. Such a curing agent provides a particularly good surface when cured under low temperature conditions.

[0045] Most preferably, the curing agent comprises a combination of salicylic acid and 2,4,6-tris(dimethylaminomethyl)phenol, which is present in an amount ranging from 1 to 15 parts by weight, preferably from 2 to 12 parts by weight, and more preferably from 3 to 10 parts by weight, per 100 parts by weight of the total of IPDA and N-benzylethane-1,2-diamine. Such curing agents allow for particularly fast curing in combination with a particularly good surface, especially when curing under low temperature conditions.

[0046] Suitable thinners include, inter alia, xylene, 2-methoxyethanol, dimethoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol, benzyl alcohol, ethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol diphenyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-butyl ether, propylene glycol butyl ether, propylene glycol phenyl ether, dipropylene glycol dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol di-n-butyl ether, diphenylmethane, diisopropyl naphthalene, mineral oil fractions such as Solvesso® grades (manufactured by Exxon), alkylphenols such as tert-butylphenol, nonylphenol, dodecylphenol, cardanol (obtained from cashew nut shell oil and containing 3-(8,11-pentadecadienyl)phenol as its main constituent), styrenated phenol, bisphenols, aromatic hydrocarbon resins, especially those containing phenolic groups, alkoxylated phenols, especially ethoxylated or propoxylated phenols, especially 2-phenoxyethanol, adipates, sebacates, phthalates, benzoates, organic phosphates or sulfonates or sulfonamides.

[0047] Preferred thinners have a boiling point above 200°C.

[0048] The thinner is preferably selected from the group consisting of benzyl alcohol, styrenated phenol, ethoxylated phenol, aromatic hydrocarbon resins containing phenolic groups, especially Novares® LS 500, LX 200, LA 300 or LA 700 products (manufactured by Ruetgers), diisopropyl naphthalene and cardanol.

[0049] Benzyl alcohol is particularly preferred.

[0050] Phenol-containing thinners are also effective as curing accelerators.

[0051] The hardener may comprise further components, in particular: monoamines, such as, in particular, benzylamine or furfurylamine; - polyamidoamines, in particular reaction products of monobasic or polybasic carboxylic acids or their esters or anhydrides, in particular dimer fatty acids, with polyamines, in particular DETA or TETA, used in stoichiometric excess; Mannich bases, especially phenalkamines, ie reaction products of phenols, especially cardanol, with aldehydes, especially formaldehyde, and polyamines. aromatic polyamines, such as in particular 4,4'-, 2,4'- and / or 2,2'-diaminodiphenylmethane, 2,4- and / or 2,6-tolylenediamine, 3,5-dimethylthio-2,4-tolylenediamine and / or 3,5-dimethylthio-2,6-tolylenediamine, 3,5-diethyl-2,4-tolylenediamine and / or 3,5-diethyl-2,6-tolylenediamine; - 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 may include:

[0052] The hardener preferably has only a low content of further amines.

[0053] In particular, at least 30%, preferably at least 40%, more preferably at least 50%, and especially at least 60% of all amine hydrogens present in the hardener are derived from N-benzylethane-1,2-diamine and IPDA. Such hardeners offer an attractive combination of fast cure, low tendency to blush, high hardness, and high glass transition temperature.

[0054] The hardener preferably only has a low amount of thinner, more particularly 0% to 50% by weight, preferably 0% to 30% by weight, of thinner, especially benzyl alcohol.

[0055] The curing agent of the present invention is preferably not water-based. It contains less than 15% by weight, preferably less than 10% by weight, of water. Such a curing agent is suitable for non-aqueous epoxy resin products, especially floor coatings.

[0056] The present invention provides a resin component comprising at least one epoxy resin; a hardener component comprising the hardener of the present invention; The present invention further provides an epoxy resin composition comprising:

[0057] Suitable epoxy resins are obtainable in known manner, inter alia, from the reaction of epichlorohydrin with polyols, polyphenols or amines.

[0058] Suitable epoxy resins are especially aromatic epoxy resins, especially bisphenol A, bisphenol F or bisphenol A / F (where A represents acetone, used as a reactant in the preparation of these bisphenols, and F represents formaldehyde). In the case of bisphenol F, positional isomers may also be present, more particularly those derived from 2,4'- or 2,2'-hydroxyphenylmethane. dihydroxybenzene derivatives, such as resorcinol, hydroquinone or catechol; further 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( ... 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-1-naphthyl)methane, bis(4-hydroxy-1-naphthyl)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 cresol with formaldehyde or paraformaldehyde or acetaldehyde or crotonaldehyde or isobutyroaldehyde 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); It is a glycidyl ether of

[0059] Further suitable epoxy resins are aliphatic or cycloaliphatic polyepoxides, especially - saturated or unsaturated, branched or unbranched, cyclic or open-chain di-, tri- or tetrafunctional C2-C 30 glycidyl ethers of alcohols, especially ethylene glycol, propylene glycol, butylene glycol, hexanediol, octanediol, polypropylene glycol, dimethylolcyclohexane, neopentyl glycol, dibromoneopentyl glycol, castor oil, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol or glycerol, or alkoxylated glycerol or alkoxylated trimethylolpropane; - hydrogenated bisphenol A, F or A / F liquid resins or glycidylation products of hydrogenated bisphenol A, F or A / F; N-glycidyl derivatives of amide or heterocyclic nitrogen bases, such as triglycidyl cyanurate or triglycidyl isocyanurate, or reaction products of epichlorohydrin with hydantoin is.

[0060] The epoxy resin is preferably a liquid resin or a mixture comprising two or more liquid epoxy resins.

[0061] "Liquid epoxy resin" refers to a commercial polyepoxide having a glass transition temperature below 25°C.

[0062] The resin component optionally contains a small proportion of solid epoxy resin as well.

[0063] The epoxy resins are liquid bisphenol-based resins, especially bisphenol A diglycidyl ether and / or bisphenol F diglycidyl ether, such as those commercially available from Olin, Huntsman, or Momentive. These liquid resins have low viscosity for epoxy resins, allowing for fast cure and high hardness. They may contain a small percentage of solid bisphenol A resin or novolac glycidyl ether.

[0064] The resin component may include a reactive diluent.

[0065] Preferred reactive diluents are reactive diluents containing epoxy groups, especially butanediol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane di- or triglycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, guaiacol glycidyl ether, 4-methoxyphenyl glycidyl ether, p-n-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, C8-C6 10 Or C 12 ~C 14 Or C 13 ~C 15 It is an alkyl glycidyl ether.

[0066] The epoxy resin composition preferably comprises at least one further component selected from the group consisting of a thinner, a curing accelerator, and a filler.

[0067] Suitable hardening accelerators are those already mentioned, especially salicylic acid, calcium nitrate or 2,4,6-tris(dimethylaminomethyl)phenol or combinations thereof. Particularly preferred is salicylic acid, especially in combination with 2,4,6-tris(dimethylaminomethyl)phenol.

[0068] Suitable thinners are those already mentioned, especially those with a boiling point above 200°C.

[0069] The thinner is preferably selected from the group consisting of benzyl alcohol, styrenated phenol, ethoxylated phenol, aromatic hydrocarbon resins containing phenolic groups, especially Novares® LS 500, LX 200, LA 300 or LA 700 products (manufactured by Ruetgers), diisopropyl naphthalene and cardanol.

[0070] Benzyl alcohol is particularly preferred.

[0071] Suitable fillers are in particular ground or precipitated calcium carbonate, barite, talc, quartz flour, silica sand, silicon carbide, biotite, dolomite, wollastonite, kaolin, mica (potassium aluminum silicate), molecular sieves, aluminum 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 beads, optionally coated with fatty acids, especially stearates.

[0072] Calcium carbonate, quartz flour, silica sand or combinations thereof are preferred.

[0073] The epoxy resin composition may optionally contain auxiliaries and additives, in particular: reactive diluents, especially those already mentioned, or epoxidized soybean or linseed oil, compounds containing acetoacetate groups, especially acetoacetylated polyols, butyrolactone, carbonates, aldehydes, isocyanates or silicones with reactive groups; - polymers, in particular polyamides, polysulfides, polyvinyl formal (PVF), polyvinyl butyral (PVB), polyurethanes (PUR), polymers containing carboxyl groups, polyamides, butadiene-acrylonitrile copolymers, styrene-acrylonitrile copolymers, butadiene-styrene copolymers, in particular homopolymers or copolymers of unsaturated monomers from the group consisting of ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or alkyl (meth)acrylates, in particular chlorosulfonated polyethylene or fluorine-containing polymers or sulfonamide-modified melamine; - fibres, in particular glass, carbon, metal, ceramic or polymer fibres, such as polyamide or polyethylene fibres; pigments, in particular titanium dioxide, iron oxide or chromium(III) oxide; - rheology modifiers, in particular thickeners or anti-settling agents; - adhesion promoters, especially organoalkoxysilanes; - flame retardant substances, in particular the aluminium hydroxide or magnesium hydroxide fillers already mentioned, 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, i.e. 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) 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 resin, ethylene bis(tetrabromophthalimide), ethylene bis(dibromonolbornanedicarboxamide), 1,2-bis(tribromophenoxy)ethane, tris(2,3-dibromopropyl)isocyanurate, tribromophenol, hexabromocyclododecane, bis(hexachlorocyclopentadieno)cyclooctane, or chloroparaffins; or - additives, in particular dispersing paraffin waxes, film-forming aids, wetting agents, levelling agents, defoamers, degassing agents, stabilizers against oxidation, heat, light or UV radiation, or biocides Further includes:

[0074] The epoxy resin composition preferably comprises further auxiliaries and additives, especially pigments, wetting agents, leveling agents and / or defoamers.

[0075] The epoxy resin composition preferably has only a low content of thinner, preferably less than 20% by weight, more preferably less than 15% by weight, especially less than 10% by weight, which allows for low or no emission of the epoxy resin product.

[0076] The epoxy resin composition preferably has only a low content of water, preferably less than 5% by weight, in particular less than 1% by weight.

[0077] In the epoxy resin composition, the ratio of the number of groups highly reactive with epoxy groups to the number of epoxy groups is preferably within the range of 0.5 to 1.5, particularly 0.7 to 1.2.

[0078] The primary and secondary amino groups present in the epoxy resin composition, as well as any further groups present that are highly reactive towards epoxy groups, react with the epoxy group, resulting in its ring opening (addition reaction). As a result of this reaction, the composition first polymerizes and thereby cures.

[0079] The resin component and the hardener component of the epoxy resin composition are stored in separate containers. The additional components of the epoxy resin composition can be present as components of the resin component or of the hardener component; the additional component that is highly reactive with epoxy groups is preferably a component of the hardener component. It is also possible for the additional components to be present as separate additional components.

[0080] Suitable containers for storing the resin or hardener components are, inter alia, vats, hobboxes, bags, buckets, cans, cartridges, or tubes. The components are storable, meaning that they can be stored for several months to over a year before use without any change in their respective properties to an extent relevant to their use. For use of the epoxy resin composition, the components are mixed together immediately before or during application. The mixing ratio between the resin and hardener components is preferably selected so that the groups of the hardener component that are highly reactive with epoxy groups are in a suitable ratio to the epoxy groups of the resin component, as described above. In parts by weight, the mixing ratio between the resin and hardener components is usually in the range of 1:10 to 10:1.

[0081] The components are mixed by any suitable method; this mixing can be done continuously or batchwise. If the mixing is not done immediately before application, it must be ensured that too much time does not pass between mixing the components and their application, and that the application occurs within the pot life. Mixing is typically done at ambient temperature, typically within the range of about 5 to 40°C, preferably about 10 to 35°C.

[0082] Curing by chemical reaction begins with mixing the two components as described above. Curing is typically carried out at temperatures ranging from 0 to 150°C. It is preferably carried out at ambient temperature and typically extends over a period of a few days to several weeks. The duration depends on factors such as temperature, the reactivity of the components and their stoichiometry, as well as the presence of curing accelerators.

[0083] When freshly mixed, the epoxy resin composition has a low viscosity. The viscosity at 20°C 10 minutes after mixing the resin and hardener components is preferably 10 s -1 The viscosity of the polymer is in the range of 100 to 4000 mPa·s, preferably 200 to 3000 mPa·s, more preferably 200 to 2000 mPa·s, and particularly 200 to 1500 mPa·s, as measured using a cone-plate viscometer at a shear rate of 100 to 4000 mPa·s, preferably 200 to 3000 mPa·s, more preferably 200 to 2000 mPa·s, and particularly preferably 200 to 1500 mPa·s.

[0084] When cured under low temperature conditions at 8°C and 80% relative humidity, the Shore D hardness after 24 hours is preferably at least 11. This is particularly achieved using a curing agent in which the ratio of the number of amine hydrogens from IPDA and N-benzylethane-1,2-diamine is in the range of 70 / 30 to 20 / 80, and in particular further comprising salicylic acid.

[0085] The epoxy resin composition is applied to at least one substrate, the following substrates being particularly suitable: glass, glass ceramics, concrete, mortar, cement screed, fibre cement, brick, tile, plaster or natural stone, such as granite or marble; - Repair or leveling compounds based on PCC (polymer modified cement mortar) or RCC (epoxy resin modified cement mortar); - metals or alloys, such as aluminium, iron, steel, copper, surface-upgraded metals or alloys, such as galvanised or chrome-plated metals, and other non-ferrous metals; - Asphalt or bitumen; leather, textiles, paper, wood, wood materials glued with resins, for example phenolic, melamine or epoxy resins, resin-textile composites or further so-called polymer composites; - plastics, such as rigid and flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM or EPDM (in each case untreated or surface-treated, for example by plasma, corona or flame); - Fiber reinforced plastics, such as carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFRP) and sheet molding compounds (SMC); - insulating foams, especially made of EPS, XPS, PUR, PIR, rock wool, glass wool or foam glass; - coated or painted substrates, in particular painted tiles, coated concrete, powder-coated metals or alloys or painted metal sheets; - Coated floors that have been overcoated with a coating, paint or varnish, especially a further floor covering layer.

[0086] If necessary, the substrate can be pretreated before application by, inter alia, physical and / or chemical cleaning methods or the application of an activator or primer.

[0087] Curing the epoxy resin composition provides a cured composition.

[0088] Once cured, the epoxy resin composition has a high glass transition temperature (Tg) of at least 45°C, preferably at least 50°C, during the first heating (first run) and at least 60°C, preferably at least 65°C, after a curing time of 14 days at room temperature, as measured by DSC using the following measurement program: (1) 2 min -10°C, (2) 10 K / min heating rate from -10 to 200°C (=first run), (3) -50 K / min cooling rate from 200 to -10°C, (4) 2 min -10°C, (5) 10 K / min heating rate from -10 to 180°C (=second run).

[0089] The epoxy resin composition is preferably used as a coating, primer, adhesive, sealant, potting compound, casting resin, impregnating resin or as a matrix for fiber composite materials, such as in particular CFRP or GFRP.

[0090] The epoxy resin compositions are particularly preferably used as coatings, which is understood here to mean all kinds of coverings that are applied over an area, especially floor coverings, paints, varnishes, sealants, base coats, primers or protective coatings, especially also those for strong corrosion protection.

[0091] The epoxy resin compositions are particularly suitable as floor coverings or floor coatings indoors, such as in offices, industrial halls, sports halls or cold rooms, or outdoors for balconies, terraces, multi-storey car parks, bridges or roofs, as protective coatings for concrete, cement, metal, plastic or wood, for example for surface sealing of wooden constructions, vehicles, loading docks, tanks, silos, shafts, pipelines, machinery or steel constructions, such as ships, quays, offshore platforms, lock gates, hydroelectric power plants, river constructions, swimming pools, wind turbines, bridges, chimneys, cranes or sheet pile walls, or as undercoats, tie coats or anticorrosive primers or for hydrophobizing surfaces.

[0092] The epoxy resin compositions are particularly advantageously used for low-emission coatings with environmental quality certification, for example according to Emicode (EC1 Plus), AgBB, DIBt, Der Blaue Engel, AFSSET, RTS (M1) and the US Green Building Council (LEED).

[0093] For use as a coating, the epoxy resin composition advantageously has a fluid consistency with low viscosity and good leveling properties. The mixed composition is typically applied to the surface of a substrate within its pot life (working time) as a thin film having a layer thickness of about 50 μm to about 5 mm, typically at ambient temperature. It is typically applied by pouring onto the substrate to be coated and then spreading it evenly, for example, with a doctor blade or a notched trowel. It can also be applied with a brush or roller, or in the form of a spray application, such as for anti-corrosion coatings on steel. Curing typically produces a substantially uniform, glossy, and non-tacky film of high hardness with good adhesion to a wide variety of different substrates.

[0094] The present invention therefore further provides a coating method comprising the steps of: (i) mixing the components of the epoxy resin composition; (ii) applying the mixed composition to a substrate within the pot life, followed by curing the mixed composition;

[0095] It is possible to apply a further coating to the fully or partially cured composition, in which case the further layer may also be an epoxy resin composition or another material, especially a polyurethane or polyurea coating.

[0096] It is also preferred to use the epoxy resin composition as an adhesive. When used as an adhesive, the epoxy resin composition typically has a paste-like consistency with structurally viscous properties after the components are mixed. During application, the mixed adhesive is applied to at least one of the substrates to be bonded within its pot life, and the two substrates are joined to form an adhesive bond within the open time of the adhesive.

[0097] The mixed adhesive is applied by means of a brush, roll, spatula, doctor blade or trowel, among others, or from a tube, cartridge or metering device.

[0098] The adhesive is suitable for use in the construction industry, in particular for the strengthening of buildings with steel sheets or sheets made of carbon fiber reinforced composite plastics (CFRP), for buildings containing bonded precast concrete components, in particular bridges or concrete towers, shafts, pipelines or tunnels, for example for wind turbines, or for buildings containing bonded natural stone, ceramic elements or parts made of fiber cement, steel, cast iron, aluminum, wood or polyester, for fixing dowels or steel rods in boreholes, for example for fixing handrails, balustrades or door frames, for repairs in concrete maintenance, especially filling of edges, holes or joints, or for bonding polyvinyl chloride (PVC) films, softened polyolefins (Combiflex®) or adhesive-modified chlorosulfonated polyethylene (Hypalon®) to concrete or steel.

[0099] Further fields of use relate to structural bonding in the construction or manufacturing industry, inter alia as adhesive mortars, assembly adhesives, reinforced adhesives, in particular as reinforced adhesives, such as for bonding thin sheets made of CFRP or steel to concrete, brickwork or wood, e.g. as element adhesives for bridge elements, sandwich element adhesives, facade element adhesives, reinforced adhesives, car body adhesives or half-shell adhesives for wind turbine rotor blades.

[0100] Such epoxy resin adhesives are also suitable for filling cavities, such as gaps, cracks or drilled holes, where the adhesive is poured or injected into the cavity and, after hardening, fills it and joins or bonds the sides of the cavity to one another with a force fit.

[0101] The present invention therefore further provides a bonding method comprising the steps of: (i) mixing the components of the epoxy resin composition; (ii) The mixed composition is subjected to the following steps within the pot life: - applied to at least one of the substrates to be bonded, joining the substrates and forming a bond within the open time; or - applying into a cavity or gap between two or more substrates, optionally inserting anchors into the cavity or gap within the open time; The mixed composition is then cured.

[0102] "Anchor" here more specifically refers to a rebar, a threaded rod or a bolt, such an anchor being adhesively bonded to a wall, ceiling or foundation, in particular with a portion of it adhered in a force-compatible manner and a portion of it protruding, and capable of bearing a construction load.

[0103] The same or different substrates may be bonded.

[0104] Application and curing of the epoxy resin composition provides the article.

[0105] The present invention therefore further provides articles resulting from the use of the epoxy resin composition.

[0106] The article is preferably a building or part thereof, in particular an above-ground or underground building, an office, an industrial hall, a sports hall, a cold room, a silo, a bridge, a roof, a staircase, a floor, a balcony, a terrace or a multi-storey car park, or an industrial or consumer item, in particular a quay, an offshore platform, a lock gate, a crane, a sheet pile wall, a pipeline or a rotor blade of a wind turbine, or a means of transport, such as in particular a car, a truck, a rail vehicle, a ship, an aircraft or a helicopter, or an installable component thereof.

[0107] The epoxy resin composition is characterized by advantageous properties. It has, in particular, a low viscosity and therefore excellent processability, cures reproducibly and quickly, especially even under humid and low-temperature conditions, and provides coatings of high mechanical quality with high hardness, high glass transition temperature, good surface, and surprisingly little tendency to yellow. Such epoxy resin compositions are particularly suitable as coatings, especially for floors. [Example]

[0108] Examples are presented herein below that are intended to further clarify the invention as described, but the invention is not, of course, limited to these described examples.

[0109] "AHEW" stands for amine hydrogen equivalent weight.

[0110] "EEW" stands for epoxy equivalent weight.

[0111] "Standard Climatic Conditions" ("SCC") refers to a temperature of 23±1°C and a relative air humidity of 50±5%.

[0112] Chemicals used were from Sigma-Aldrich Chemie GmbH unless otherwise stated.

[0113] Measurement method description: Viscosity was measured using a thermostatic Rheotec RC30 cone-plate viscometer (cone diameter 50 mm, cone angle 1°, cone tip-plate diameter 0.05 mm, shear rate 10 s -1 ) was measured.

[0114] Amine value was determined by titration (with 0.1 N HClO4 in acetic acid against crystal violet).

[0115] Substances and abbreviations used: Araldite® GY 250: Bisphenol A diglycidyl ether, EEW 187 g / eq (Huntsman) Araldite® DY-E: C 12 ~C 14 Monoglycidyl ether of alcohol, EEW approx. 290g / equivalent (Huntsman) IPDA: 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, AHEW 42.6 g / eq (Vestamin® IPD from Evonik) B-EDA: N-benzylethane-1,2-diamine, prepared as follows, 150.2 g / mol, AHEW 50 g / eq. BAC 1,3-bis(aminomethyl)cyclohexane, AHEW 35.5g / equivalent (Mitsubishi Gas Chemical Company) MXDA 1,3-bis(aminomethyl)benzene, AHEW 34g / equivalent (Mitsubishi Gas Chemical Company) TMD 2,2(4),4-trimethylhexamethylenediamine, AHEW 39.6 g / eq (Vestamin® TMD from Evonik) TEPA Tetraethylenepentamine, AHEW approx. 30g / equivalent (industrial grade, manufactured by Huntsman) Ancamine® K54 2,4,6-tris(dimethylaminomethyl)phenol (Air Products)

[0116] N-benzylethane-1,2-diamine (B-EDA): A round-bottom flask was charged with 180.3 g (3 mol) of ethane-1,2-diamine at room temperature under a nitrogen atmosphere. A solution of 106.0 g (1 mol) of benzaldehyde in 1200 ml of isopropanol was slowly added dropwise with thorough stirring, and stirring was continued for an additional 2 hours. The reaction mixture was then hydrogenated in a continuous hydrogenation apparatus using a Pd / C fixed-bed catalyst at 80 bar hydrogen pressure, a temperature of 80°C, and a flow rate of 5 ml / min. IR spectroscopy was used to monitor the reaction, with an IR peak at approximately 1665 cm -1 The hydrogenation solution was checked for the disappearance of the imine band at 8.5°C. The hydrogenation solution was then concentrated on a rotary evaporator at 65°C to remove unreacted ethane-1,2-diamine, water, and isopropanol. The reaction mixture thus obtained was a clear, pale yellow liquid having an amine value of 678 mg KOH / g and containing approximately 85 wt% N-benzylethane-1,2-diamine (retention time 8.47-8.57 min) as determined by GC.

[0117] 120 g of this reaction mixture was purified by distillation at 80 °C under reduced pressure, resulting in 75.1 g of distillate (N-benzylethane-1,2-diamine) collected at a vapor temperature of 60-65 °C and 0.06 mbar. A colorless liquid was obtained with a viscosity of 8 mPa s at 20 °C, an amine number of 750 mg KOH / g, and a purity of >97%, as measured by GC. This was used for further examples.

[0118] Preparation of hardener and epoxy resin composition: Examples 1 to 18: For each example, the components of the resin components specified in Tables 1-3 were mixed in the amounts (in parts by weight) specified using a centrifugal mixer (SpeedMixer™ DAC 150, FlackTek Inc.), and stored with the exclusion of moisture.

[0119] The components of the hardener composition specified in Tables 1-3 were treated and stored similarly.

[0120] The two components of each composition were then processed using a centrifugal mixer to form a homogeneous liquid, which was immediately tested as follows: After 10 minutes of mixing, the viscosity was measured at 20° C. (“Viscosity (10 min)”).

[0121] Gel time was measured under standard climatic conditions by occasionally stirring the mixed composition (25 g) with a spatula until it began to gel.

[0122] For the determination of the Shore D hardness in accordance with DIN 53505, two cylindrical test specimens (diameter 20 mm, thickness 5 mm) were prepared in each case: one was stored under standard climatic conditions and the hardness was measured after 1 and 2 days (1d SCC and 2d SCC); the other was stored at 8°C and 80% relative humidity and the hardness was measured after 1 and 2 days at low temperature (1d 8°C / 80% and 2d 8°C / 80%).

[0123] The first film coating was applied to a glass plate with a layer thickness of 500 μm, which was then stored / cured under standard conditions. The Koenig hardness (Koenig pendulum hardness, measured according to DIN EN ISO 1522) of this film was measured after 1 day ("Koenig hardness (1d SCC)"), 2 days ("Koenig hardness (2d SCC)"), 4 days ("Koenig hardness (4d SCC)"), 7 days ("Koenig strength (7d SCC)"), and 14 days ("Koenig hardness (14d SCC)"). After 14 days, the appearance of the film was evaluated (designated "Appearance (SCC)" in the table). A film was described as "good" if it had a glossy, non-sticky surface without structure. "Structure" refers to any kind of marking or pattern on the surface. Films with reduced gloss were designated as "matt."

[0124] The second film coating was applied to a glass plate with a layer thickness of 500 μm, which was immediately stored / cured at 8 °C and 80% relative humidity for 7 days after application, and then for 2 weeks under standard climatic conditions. 24 hours after application, a polypropylene bottle cap, underneath which a moistened sponge had been placed, was placed on the film. After another 24 hours, the sponge and bottle cap were removed and placed on a new spot on the film, from which it was removed and replaced after another 24 hours, a total of four times. The appearance of the film was then evaluated in the same manner as described for appearance (SCC) (designated "Appearance (8 °C / 80%)" in the table). The number and nature of visible marks formed on the film as a result of the moistened sponge or bottle cap on top were also reported in each case. The number of white discolored spots was reported as "blush." ​​Faint white discolored spots were designated "(1)." Obvious white discolored spots were designated "1." The designation "Ring" was reported if a ring-shaped mark was present due to settling of the lid of the first bottle, which had been left for 24 hours after application. Such a ring-shaped mark indicates that the coating had not hardened and could not be walked on immediately. Very minimal ring-shaped marks were designated "(present)." Obvious ring-shaped marks were designated "present." The Koenig hardness of the thus cured films was measured again after 7 days at 8°C and 80% relative humidity in each case ("Koenig Hardness (7d 8°C / 80%)") and then after a further 2 days under SCC ("Koenig Hardness (+2d SCC)"), after 7 days under SCC ("Koenig Hardness (+7d SCC)"), and after 14 days under SCC ("Koenig Hardness (+14d SCC)").

[0125] Tg (glass transition temperature) was determined by DSC on cured samples stored for 14 days under standard climatic conditions using a Mettler Toledo DSC 3+700 instrument and the following measurement program: (1) 2 min -10°C, (2) 10 K / min heating rate from -10 to 200°C (= 1st run), (3) -50 K / min cooling rate from 200 to -10°C, (4) 2 min -10°C, (5) 10 K / min heating rate from -10 to 180°C (= 2nd run).

[0126] As a measure of yellowing, the change in color after stress in a weathering tester was measured. For this purpose, a further film coating was applied to a glass plate in a layer thickness of 500 μm, which was stored / cured under standard climatic conditions for 2 weeks and then exposed to a Q-SUN Daylight-Q optical filter and 0.51 W / m at 340 nm. 2 The films were stressed for 72 hours at a temperature of 65°C in a model Q-Sun Xenon Xe-1 weathering tester equipped with a xenon lamp having a light intensity of 1000 Hz and 1000 Hz (Q-Sun (72h)). The color difference ΔE between the stressed films and the corresponding unstressed films was then measured using a Shenzen 3NH Technology Co., Ltd. NH310 colorimeter equipped with a silicon photoelectric diode detector, Illuminant A, and a color space measurement interface CIE L*a*b*C*H*.

[0127] The results are reported in Tables 1-3.

[0128] Examples designated with "(Ref.)" are comparative examples.

[0129] [Table 1]

[0130] [Table 2]

[0131] [Table 3]

[0132] Examples 19 to 21 For these examples, filled, commercially available resin components were used in the amounts shown in Table 4: Sikafloor®-264N Component A RAL 5005 (manufactured by Sika).

[0133] The components of the curing agent component shown in Table 4 were processed and stored as described above. The two components were then processed to a homogeneous liquid as described above and tested as specified for Example 1.

[0134] The results are reported in Table 4.

[0135] [Table 4] The present disclosure includes the following inventive aspects: <Aspect 1> A curing agent for epoxy resins, comprising 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzylethane-1,2-diamine in amounts such that the ratio of the numbers of amine hydrogens therein is within the range of 90 / 10 to 20 / 80. <Aspect 2> 2. The curing agent according to aspect 1, characterized in that less than 10 wt. %, more preferably less than 5 wt. %, especially less than 1 wt. % of 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane is present adducted with the epoxy resin. <Aspect 3> 3. The curing agent according to any one of the preceding aspects, wherein the N-benzylethane-1,2-diamine has a purity of at least 80% by weight. <Aspect 4> 4. The curing agent according to any one of aspects 1 to 3, characterized in that less than 10 wt. % of N-benzylethane-1,2-diamine is present adducted with the epoxy resin, more preferably less than 5 wt. %, especially less than 1 wt. %. <Aspect 5> 5. The curing agent according to any one of Aspects 1 to 4, wherein the ratio of the numbers of amine hydrogens from 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzylethane-1,2-diamine is within the range of 80 / 20 to 25 / 75, preferably 75 / 25 to 30 / 70. <Aspect 6> 6. The curing agent according to any one of the preceding aspects, characterized in that at least one further component selected from the group consisting of a further amine, a curing accelerator, and a reducer is present. <Aspect 7> 7. The curing agent according to any one of aspects 1 to 6, characterized in that at least 30%, preferably at least 40%, more preferably at least 50%, and especially at least 60% of all the amine hydrogens present in the curing agent are derived from 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzylethane-1,2-diamine. <Aspect 8> 8. The curing agent according to any one of aspects 1 to 7, comprising salicylic acid. <Aspect 9> An epoxy resin composition comprising: a resin component comprising at least one epoxy resin; and A curing agent component comprising the curing agent according to any one of aspects 1 to 8. <Aspect 10> 10 minutes after mixing the resin component and the hardener component, -1 10. The epoxy resin composition according to Aspect 9, characterized in that the composition has a viscosity at 20°C, measured using a cone-plate viscometer at a shear rate of 100 to 4000 mPa s, preferably 200 to 3000 mPa s, more preferably 200 to 2000 mPa s, and especially 200 to 1500 mPa s. <Aspect 11> 11. The epoxy resin composition according to claim 9 or 10, characterized in that after mixing the components and after a curing time of 14 days at room temperature, the composition has a glass transition temperature during the first heating (first run) of at least 45°C, preferably at least 50°C, and during the second heating (second run) of at least 60°C, preferably at least 65°C, measured by DSC with a measuring program of: (1) 2 min −10°C, (2) a heating rate of 10 K / min from −10 to 200°C (=first run), (3) a cooling rate of −50 K / min from 200 to −10°C, (4) 2 min −10°C, (5) a heating rate of 10 K / min from −10 to 180°C (=second run). <Aspect 12> 12. Use of the epoxy resin composition according to any one of aspects 9 to 11 as a coating, primer, adhesive, sealant, potting compound, casting resin, impregnating resin or as a matrix for fiber composites. <Aspect 13> A coating method comprising the steps of: (i) mixing the components of the epoxy resin composition according to any one of aspects 9 to 11; (ii) applying the mixed composition to a substrate within the pot life, followed by curing said mixed composition; <Aspect 14> A bonding method comprising the steps of: (i) mixing the components of the epoxy resin composition according to any one of Aspects 9 to 11; (ii) The mixed composition is subjected to the following steps within the pot life: - applied to at least one of the substrates to be bonded and joining said substrates to form a bond within the open time; or - applying into cavities or gaps between two or more substrates, and optionally inserting anchors into said cavities or gaps within the open time; Then, the mixed composition is cured. <Aspect 15> 15. An article obtained from the use according to aspect 12 or the method according to aspect 13 or 14.

Claims

1. A curing agent for epoxy resins, comprising 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzylethane-1,2-diamine in amounts such that the ratio of the number of amine hydrogens therein is within a range of 90 / 10 to 20 / 80, wherein the curing agent comprises a combination of salicylic acid and 2,4,6-tris(dimethylaminomethyl)phenol.

2. 2. The hardener of claim 1, wherein less than 10% by weight of 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane is present in the epoxy resin adduct.

3. 3. The curing agent according to claim 1, wherein the N-benzylethane-1,2-diamine has a purity of at least 80% by weight.

4. 4. The hardener according to claim 1, wherein less than 10% by weight of N-benzylethane-1,2-diamine is present in the adduct with the epoxy resin.

5. The curing agent according to any one of claims 1 to 4, characterized in that the ratio of the numbers of amine hydrogens from 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzylethane-1,2-diamine is in the range of 80 / 20 to 25 / 75.

6. 6. The curing agent according to claim 1, wherein at least one further component is present selected from the group consisting of further amines, curing accelerators, and thinners.

7. 7. The curing agent of claim 1, wherein at least 30% of all the amine hydrogens present in the curing agent are derived from 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and N-benzylethane-1,2-diamine.

8. An epoxy resin composition comprising: a resin component comprising at least one epoxy resin; and A hardener component comprising the hardener according to any one of claims 1 to 7.

9. 10 minutes after mixing the resin component and the hardener component, －１ 9. The epoxy resin composition according to claim 8, characterized in that it has a viscosity at 20°C in the range of 100 to 4000 mPa·s, as measured using a cone-plate viscometer at a shear rate of 100 to 4000 mPa·s.

10. The epoxy resin composition according to claim 8 or 9, characterized in that after mixing the resin component and the hardener component and after a curing time of 14 days at room temperature, the composition has a glass transition temperature during a first heating (first run) of at least 45°C and during a second heating (second run) of at least 60°C, as measured by DSC with the following measurement programs: (1) 2 min at -10°C, (2) a heating rate of 10 K / min from -10 to 200°C (=first run), (3) a cooling rate of -50 K / min from 200 to -10°C, (4) 2 min at -10°C, (5) a heating rate of 10 K / min from -10 to 180°C (=second run).

11. Use of the epoxy resin composition according to any one of claims 8 to 10 as a coating, primer, adhesive, sealant, potting compound, casting resin, impregnating resin or as a matrix for fibre composites.

12. A coating method comprising the steps of: (i) mixing the resin component of the epoxy resin composition according to any one of claims 8 to 10 with the curing agent component; (ii) applying the mixed composition to a substrate within the pot life, followed by curing said mixed composition;

13. A bonding method comprising the steps of: (i) mixing the resin component of the epoxy resin composition according to any one of claims 8 to 10 with the curing agent component; (ii) The mixed composition is subjected to the following steps within the pot life: - applied to at least one of the substrates to be bonded and joining said substrates to form a bond within the open time, or - application into cavities or gaps between two or more substrates, optionally inserting anchors into said cavities or gaps within the open time; Then, the mixed composition is cured.

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