ELECTRICALLY CONDUCTIVE EPOXY RESIN COATING AND ELECTROSTATIC-DISSIPATIVE FLOOR

Description

Technical area

[0001] The invention relates to electrically conductive epoxy resin coatings and their use in electrostatically dissipative floors. State of the art

[0002] Electrostatically dissipative floors, also known as ESD floors (for "electrostatic dissipative"), are well known. They are designed to conduct electrostatic charges generated in a room, for example, by walking or driving on it, to a grounding point via footwear and the floor. This prevents spontaneous electrostatic discharges that can lead to defects or malfunctions in the production or handling of sensitive products or instruments.

[0003] An electrostatically conductive floor must have such low electrical resistance to the ground that charges are reliably dissipated, but only so highly conductive that people's health is not endangered by contact with electrical current. Standards exist for such floors that describe test methods for electrostatic and electrical behavior. DIN EN 61340-4-1, for example, describes a test method for determining the electrical resistance of floor coverings and installed flooring, and DIN EN 61340-4-5 assesses electrostatic safety with regard to the combined electrical resistance and chargeability of people, footwear, and floor coverings.

[0004] Epoxy resin-based floors are particularly robust in terms of mechanical stress and resistance to many substances. They are therefore particularly suitable for heavily used industrial production spaces. An electrostatically dissipative epoxy resin-based floor system must fulfill a number of properties. It should develop reliable adhesion to various substrates and be as easy to install as possible. The electrostatic charges absorbed by the floor should be reliably discharged downwards. For this purpose, a so-called conduction system consisting of copper strips or wires connected to an earthing system is laid beneath the coating. The epoxy resin coating should be easy to install and compatible with the underlying conduction system. Once cured, it should have an aesthetically pleasing, even surface with high hardness and low brittleness.To achieve this, the epoxy resin coating should have a low viscosity at ambient temperatures with good flow and good air release, as well as a long open time, yet cure as quickly as possible and avoid any curing defects such as residual stickiness, stains, or cloudiness. For high slip resistance, sand can be sprinkled on the surface, which is then covered with a sealant. After curing, the coated floor should have an electrical resistance in the range of approximately 10 5 to 10 8 ohms and be robust and resilient.

[0005] Floors made from synthetic resins such as epoxy resins are insulators. There are various ways to achieve electrical conductivity. Known approaches include the use of ionic liquids or organic salts soluble in the synthetic resin matrix, which provide electrical conductivity. However, this slows down curing and massively reduces the mechanical and chemical resistance of the floor, and the electrical resistance is highly dependent on the prevailing humidity. Conductive solid particles can also be added. Metals, for example, are suitable for this purpose. These have a strong inherent color and, due to their high specific gravity, settle to the bottom of the container during storage of the still-liquid composition, making homogeneous stirring and distribution throughout the coating difficult. This leads to inconsistent electrical resistance and zones of insufficient conductivity.Other known methods include the addition of conductive carbon black or graphite, which achieves reliable conductivity but, due to their strong black color, only produces very dark to black coatings, which is generally undesirable for industrial floors. Fine carbon fibers are also well known. However, these fibers are also difficult to mix homogenously and tend to accumulate, which remains visible after curing and leads to unsightly surfaces with inconsistent resistance. More recently, carbon nanotubes (CNTs) have become known and can also be used as conductive fillers. These are carbon nanotubes whose walls consist of individual graphite layers, known as graphenes.Even with very small amounts, carbon nanotubes enable good conductivity with uniform resistance over a large area, largely independent of humidity. However, due to their high surface area, they have a strong thickening effect. This results in poor flow during application and makes it difficult to vent trapped air through the escape of rising air bubbles that burst on the surface. An electrically conductive coating based on carbon nanotubes therefore requires more care and time during application and, after curing, displays a slightly uneven surface due to incomplete venting. Electrostatically conductive floors based on epoxy resin are described, for example, in EP 1,437,182, where carbon fibers are used as conductive fillers.

[0006] Amines of formula (I) as hardeners for epoxy resins are described, for example, in EP 3,180,383 or EP 3,344,677.

[0007] DE102018009794 A1 discloses a coating composition containing an amine hardener, carbon nanotubes and epoxy resins A and F. Description of the invention

[0008] The object of the present invention is therefore to provide an electrically conductive epoxy resin coating with an electrical resistance that is largely independent of air humidity, which, when applied, shows good flow with good ventilation even without or with only a few non-integrable thinners, cures quickly and finally has an even, aesthetically pleasing surface and is suitable as a component of an electrostatically conductive floor system.

[0009] Surprisingly, the use of a combination of carbon nanotubes and at least one amine of formula (I) according to claim 1 solves this problem. Although epoxy resin coatings containing carbon nanotubes possess reliable electrical conductivity with an electrical resistance that is largely independent of atmospheric humidity, the ultrafine carbon nanotubes significantly impede flow and deaeration. Especially with filled, pigmented coatings, deaeration is so hampered that even after treating the still-liquid coating with a spiked roller or spiked shoes, a slightly uneven surface with fine, unburst bubbles is produced. The combination with the amine of formula (I) surprisingly enables significantly improved flow and deaeration, which facilitates processing and produces an attractive, particularly even surface.The inventive use enables pigmented coatings of high color intensity, as well as transparent coatings in which the amine of formula (I) surprisingly enables particularly high transparency. The cured coatings from the inventive use have an aesthetically pleasing, even surface, high hardness with low brittleness, high robustness against mechanical and chemical stress, and electrical conductivity distributed evenly over the surface, largely independent of air humidity. The inventive use also enables, in particular, electrically conductive coatings with particularly low emission of organic substances after curing, which are suitable for use in hospitals or clean rooms.

[0010] The epoxy resin coating used according to the invention enables an electrostatically conductive flooring system that is easy and straightforward to install, produces particularly low emissions, and meets the highest aesthetic standards. It enables flooring systems with colored, particularly even surfaces and flooring systems with a non-slip, transparently sealed, sanded surface.

[0011] 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

[0012] The invention relates to the use of a combination of carbon nanotubes and at least one amine of the formula (I), Z-NH-A-NH-CH 2 -Y (I) where A represents a divalent C 2 to C 15 alkylene, cycloalkylene or arylalkylene radical, which optionally contains one or more nitrogen atoms or ether groups, and Z represents H or ---CH 2 -Y, and Y represents H or a C 1 to C 12 alkyl, cycloalkyl, arylalkyl or aryl radical, where the amine of the formula (I) contains a total of at least 8 C atoms, for producing an electrically conductive epoxy resin coating.

[0013] "Carbon nanotubes" are carbon tubes with a diameter in the nanometer range, especially in the range of 1 to 50 nm, and a wall made of one or more layers of graphene, i.e. carbon with ring-shaped carbon atoms.

[0014] A composition is described as "storage-stable" if it can be stored at room temperature in a suitable container for a prolonged period, typically for at least 3 months up to 6 months or more, without its application or use properties being changed by storage to an extent relevant to its use.

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

[0016] An "epoxy liquid resin" is a technical polyepoxide with a glass transition temperature below 25°C.

[0017] "Molecular weight" refers to the molar mass (in grams per mole) of a molecule. "Mean molecular weight" is the number average Mn of a polydisperse mixture of oligomeric or polymeric molecules. It is determined by gel permeation chromatography (GPC) using polystyrene as a standard.

[0018] Pot life is the period of time from the mixing of the components of an epoxy resin composition within which the composition can be processed without any deterioration.

[0019] The term "gel time" refers to the time from the mixing of the components of an epoxy resin composition until they gel.

[0020] 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.

[0021] The hydrogen atoms of primary and secondary amino groups are called "amine hydrogen".

[0022] Amine hydrogens of amino groups bonded to an aliphatic C atom are called "aliphatic".

[0023] The "amine hydrogen equivalent weight" is the mass of an amine or amine-containing composition that contains one molar equivalent of amine hydrogen.

[0024] Substance names beginning with "poly," such as polyamine or polyepoxide, refer to substances that formally contain two or more of the functional groups mentioned in their name per molecule.

[0025] "Room temperature" is defined as 23°C. Percentages by weight (% by weight), abbreviated to wt%, refer to the mass fraction of a component of a composition or molecule relative to the total composition or molecule, unless otherwise stated. The terms "mass" and "weight" are used synonymously in this document.

[0026] All industry standards and norms mentioned in this document refer to the versions valid at the time of filing the initial application.

[0027] Carbon nanotubes are manufactured industrially and commercially available in various qualities. They exhibit interesting properties for a variety of applications. In particular, they are electrically conductive.

[0028] Single-walled carbon nanotubes, so-called "single-wall carbon nanotubes", are particularly suitable as carbon nanotubes.

[0029] They are preferably used as a dispersion in a liquid carrier material, in particular in a liquid which is well compatible with epoxy resin compositions, in particular an alkyl glycidyl ether, a fatty acid ester or an ethoxylated alcohol.

[0030] Preferred is a dispersion containing 10% by weight of carbon nanotubes, especially in an alkyl glycidyl ether, especially a C 12 to C 14 alkyl glycidyl ether, such as is also used as a reactive diluent for epoxy resins. Such a dispersion is commercially available, for example, as Tuball® Matrix 207 (from OCSiAl).

[0031] Even a very small amount of carbon nanotubes in terms of weight enables good electrical conductivity, but also causes a significant increase in viscosity and flow properties and a certain darkening of the coating.

[0032] Preferably, the carbon nanotubes are used in such an amount that the epoxy resin coating is bright enough to be used as a pigmented, colored coating in light shades or as a transparent sealant.

[0033] Preferred is an amount in the range of 0.001 to 0.1% by weight based on the total epoxy resin coating.

[0034] Particularly preferred is an amount in the range of 0.001 to 0.05% by weight based on the total epoxy resin coating.

[0035] Thus, a dispersion with 10 wt% carbon nanotubes is preferably used in an amount in the range of 0.01 to 1 wt%, in particular 0.01 to 0.5 wt%, based on the total epoxy resin coating.

[0036] In this range, the desired electrical conductivity and a not too dark coloration are achieved.

[0037] A pigmented coating preferably contains an amount in the range of 0.01 to 0.1% by weight, in particular 0.01 to 0.05% by weight.

[0038] A transparent coating preferably contains an amount in the range of 0.001 to 0.01% by weight, in particular 0.001 to 0.005% by weight.

[0039] In the amine of formula (I), A is preferably selected from the group consisting of 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene, 1,3-butylene, 2-methyl-1,2-propylene, 1,3-pentylene, 1,5-pentylene, 2,2-dimethyl-1,3-propylene, 1,6-hexylene, 2-methyl-1,5-pentylene, 1,7-heptylene, 1,8-octylene, 2,5-dimethyl-1,6-hexylene, 1,9-nonylene, 2,2(4),4-trimethyl-1,6-hexylene, 1,10-decylene, 1,11-undecylene, 2-butyl-2-ethyl-1,5-pentylene, 1,12-dodecylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, (1,5,5-trimethylcyclohexan-1-yl)methane-1,3, 4(2)-methyl-1,3-cyclohexylene, 1,3-cyclohexylene-bis(methylene), 1,4-cyclohexylene-bis(methylene), 1,3-phenylene-bis(methylene), 1,4-phenylene-bis(methylene), 3-oxa-1,5-pentylene, 3,6-dioxa-1,8-octylene, 4,7-dioxa-1,10-decylene, 3-aza-1,5-pentylene, 3,6-diaza-1,8-octylene, 4,7-diaza-1,11-decylene and 3-aza-1,6-hexylene.

[0040] Preferably, A is free of nitrogen atoms and free of ether groups.

[0041] A preferably represents a C2 to C8 alkylene radical, in particular 1,2-ethylene, 1,2-propylene, 1,3-propylene, 1,4-butylene, 1,3-butylene, 1,5-pentylene, 1,6-hexylene, 2-methyl-1,5-pentylene, 1,7-heptylene, or 1,8-octylene. These amines of formula (I) enable particularly good flow properties.

[0042] Particularly preferably, A represents 1,2-ethylene. These amines of formula (I) enable particularly good flow, particularly good deaeration, and particularly rapid curing.

[0043] Z preferably stands for H.

[0044] In the amine of formula (I), Y is preferably selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, butyl, pentyl, heptyl, hept-2-yl, phenyl, naphthyl and cyclohexyl.

[0045] Particularly preferably, Y is phenyl or cyclohexyl, especially phenyl. Such an amine of formula (I) enables particularly rapid curing and particularly attractive, high-gloss surfaces.

[0046] Most preferred is an amine of formula (I) in which A is 1,2-ethylene, Z is H and Y is phenyl.

[0047] This amine of formula (I) is N-benzyl-1,2-ethanediamine. It enables epoxy resin coatings containing carbon nanotubes with particularly good flow and even, well-ventilated surfaces, as well as particularly rapid curing.

[0048] An amine of formula (I) in which Z is H may contain proportions of dialkylated amine, i.e., the corresponding amine in which Z is ---CH 2 -Y. It preferably contains at most 30% by weight, particularly preferably at most 20% by weight, and in particular at most 15% by weight, of dialkylated amine. Most preferably, an amine of formula (I) in which Z is H is used in a purity of at least 95% by weight.

[0049] The amine of formula (I) is preferably prepared by partial alkylation of at least one amine of formula H 2 NA-NH 2 with at least one alkylating agent.

[0050] The alkylation is preferably a reductive alkylation, wherein an aldehyde and hydrogen are used as the alkylating agent.

[0051] The reductive alkylation 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.

[0052] When using molecular hydrogen, the reductive alkylation is preferably carried out in a pressure apparatus at a hydrogen pressure of 5 to 150 bar, especially 10 to 100 bar. This can be carried out in a batch process or, preferably, in a continuous process.

[0053] The reductive alkylation is preferably carried out at a temperature in the range of 40 to 120 °C, in particular 60 to 100 °C.

[0054] In the case of small, volatile amines, such as 1,2-ethanediamine in particular, this is preferably used in a stoichiometric excess over the aldehyde, and after the alkylation, any unreacted amine is partially or completely removed from the reaction mixture, in particular by distillation or stripping. If desired, the reaction mixture can subsequently be further purified, in particular by partially or completely freeing the resulting monoalkylated amine of formula (I), in which Z is H, from the dialkylated amine, in which Z is ---CH 2 -Y, by distillation.

[0055] The amine of formula (I) can be present in free form or as an adduct with at least one epoxy resin, in particular at least one aromatic diepoxide with an epoxy equivalent weight in the range of 110 to 200 g / mol, preferably 150 to 200 g / mol, in particular a bisphenol A diglycidyl ether and / or bisphenol F diglycidyl ether. The adduct is prepared in particular with an amine excess such that at least 1.3 mol of amine of formula (I) are used per epoxy group.

[0056] The amine of formula (I) is preferably used in an amount such that at least 5%, preferably at least 10%, of all amine hydrogens present in the epoxy resin coating originate from amines of formula (I). In particular, 5 to 70%, preferably 5 to 50%, of all amine hydrogens present originate from amines of formula (I). The amine hydrogens of adducted amines of formula (I) are also included.

[0057] Another object of the invention is an electrically conductive epoxy resin coating of the described use, comprising at least one epoxy liquid resin, at least one amine of formula (I), carbon nanotubes, and at least one further component selected from the list consisting of further amines, accelerators, fillers, thinners, surface-active additives and stabilizers.

[0058] Aromatic epoxy resins, especially the glycidyl ethers of: Bisphenol A, bisphenol F, or bisphenol A / F, where A stands for acetone and F for formaldehyde, which serve as starting materials for the production of these bisphenols. In the case of bisphenol F, positional isomers may also be present, particularly those derived from 2,4'- or 2,2'-hydroxyphenylmethane. Dihydroxybenzene derivatives such as resorcinol, hydroquinone, or pyrocatechol; other bisphenols or polyphenols such as bis(4-hydroxy-3-methylphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C), bis(3,5-dimethyl-4-hydroxyphenyl)methane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-tert.butylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane (bisphenol B), 3,3-bis(4-hydroxyphenyl)pentane, 3,4-bis(4-hydroxyphenyl)hexane, 4,4-bis(4-hydroxyphenyl)heptane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,4-Bis(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane, 1,1-Bis(4-hydroxyphenyl)cyclohexane (Bisphenol Z), 1,1-Bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (bisphenol TMC), 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,4-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (bisphenol P), 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (bisphenol M), 4,4'-dihydroxydiphenyl (DOD), 4,4'-dihydroxybenzophenone, bis(2-hydroxy-naphth-1-yl)methane, bis(4-hydroxynaphth-1-yl)methane, 1,5-dihydroxynaphthalene, tris(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)ether or bis(4-hydroxyphenyl)sulfone; novolaks, which are in particular condensation products of phenol or cresols with formaldehyde; aromatic amines such as aniline, toluidine, 4-aminophenol, 4,4'-methylenediphenyldiamine, 4,4'-methylenediphenyldi-(N-methyl)amine, 4,4'-[1,4-phenylene-bis(1-methylethylidene)]bisaniline (Bisaniline P) or 4,4'-[1,3-phenylene-bis(1-methylethylidene)]bisaniline (Bisaniline M).

[0059] 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.

[0060] Particularly preferred are aromatic diepoxides that are liquid at room temperature and have an epoxy equivalent weight in the range of 110 to 200 g / mol, preferably 150 to 200 g / mol, in particular bisphenol A diglycidyl ether and / or bisphenol F diglycidyl ether, as commercially available, for example, from Olin, Huntsman, or Momentive. These liquid resins enable rapid curing and high hardness.

[0061] Together with the liquid epoxy resin, the coating may contain portions of bisphenol A solid resin or novolak glycidyl ethers or reactive diluents.

[0062] Suitable reactive diluents are 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.

[0063] The epoxy resin coating preferably contains the above-mentioned amines of formula (I) and the above-mentioned carbon nanotubes in the above-mentioned amounts.

[0064] Preferably, the epoxy resin coating contains, in addition to at least one amine of the formula (I), at least one further amine, in particular at least one further amine with at least four aliphatic amine hydrogens. Suitable amines with at least four aliphatic amine hydrogens are in particular 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-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (IPDA), 1,2-Diaminocyclohexane, 1,3-Diaminocyclohexane, 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 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, in particular polyoxypropylenediamines or polyoxypropylenetriamines 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)-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), as well as adducts of these amines with epoxy resins.

[0065] Preferably, the further amine is selected from the group consisting of TMD, IPDA, 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, 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, BHMT, DETA, TETA, TEPA, PEHA, DPTA, N3-amine, N4-amine, adducts of IPDA, MXDA, DETA, TETA or TEPA with Epoxy resins, and mixtures of two or more of the amines mentioned.

[0066] Particularly preferred are TMD, IPDA, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, MXDA, polyoxypropylenediamines having an average molecular weight M n in the range from 200 to 500 g / mol, adducts of IPDA and / or MXDA with aromatic diepoxides or mixtures of two or more of the amines mentioned.

[0067] Further suitable amines are N-aminoethylpiperazine, 3-dimethylaminopropylamine (DMAPA), 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA), monoamines, polyamidoamines, in particular reaction products of a mono- or polybasic carboxylic acid or its ester or anhydride, in particular a dimer fatty acid, with a polyamine used in stoichiometric excess, in particular DETA or TETA, Mannich bases, in particular phenalkamines, i.e. reaction products of phenols, in particular cardanol, with aldehydes, in particular formaldehyde, and polyamines, or 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.

[0068] Preferably, 5 to 50% of all amine hydrogens present in the epoxy resin coating originate from amines of the formula (I), and at least one further amine with at least four aliphatic amine hydrogens is present.

[0069] The additional amine with at least four aliphatic amine hydrogens is preferably selected from the group consisting of TMD, IPDA, 1,3-bis(aminomethyl)cyclohexane, MXDA, and polyoxypropylenediamines with an average molecular weight M n in the range of 200 to 500 g / mol. A combination of two or more of these additional amines is particularly preferred.

[0070] 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.

[0071] 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.

[0072] Suitable fillers are, in particular, ground or precipitated calcium carbonate, which may be coated with fatty acid, in particular stearates, barite (barite), talc, quartz flour, quartz sand, silicon carbide, iron mica, dolomite, wollastonite, kaolin, mica (potassium aluminum silicate), molecular sieve, aluminum oxide, zinc oxide, aluminum-doped zinc oxide, aluminum hydroxide, magnesium hydroxide, silica, cement, gypsum, fly ash, carbon black, graphite, metal powder such as aluminum, copper, iron, zinc, silver or steel, PVC powder or hollow spheres.

[0073] Preferred fillers for pigmented epoxy resin coatings include calcium carbonate, talc, quartz powder, quartz sand, dolomite, wollastonite, or kaolin, especially calcium carbonate, quartz powder, quartz sand, or a combination thereof. Due to their relatively low specific gravity, such fillers hardly sink during application and curing, enabling a largely homogeneous cured coating with particularly uniform electrical conductivity.

[0074] A preferred filler for a transparent epoxy resin coating is zinc oxide, particularly aluminum-doped zinc oxide, especially in a small amount in the range of 0.5 to 5% by weight, preferably 1 to 3% by weight, based on the total epoxy resin coating. Such an amount of zinc oxide can slightly lighten and compensate for the slightly dark gray hue of a small amount of carbon nanotubes while maintaining good electrical conductivity, thus achieving high transparency largely without darkening or lightening the substrate. Such a transparent epoxy resin coating is also suitable as a transparent sealant on all types of electrostatically conductive floors. In particular, it is suitable as a transparent sealant for surfaces sprinkled with electrically conductive quartz sand, whereby the quartz sand and the underlying coating are clearly visible through the transparent sealant.Such a surface is particularly slip-resistant and meets high aesthetic standards.

[0075] Preferably, a transparent epoxy resin coating contains less than 0.1% by weight of fillers or pigments other than carbon nanotubes and zinc oxide, in particular it is free of such fillers or pigments.

[0076] Suitable thinners are in particular 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-butylyl 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, 2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate, diphenylmethane, diisopropylnaphthalene, petroleum fractions such as Solvesso ®< types (from Exxon), alkylphenols such as tert.Butylphenol, nonylphenol, dodecylphenol, cardanol (from cashew shell oil, containing 3-(8,11-pentadecadienyl)phenol), 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.

[0077] Diluents with a boiling point above 200 °C are preferred. Benzyl alcohol is particularly preferred.

[0078] The epoxy resin coating preferably contains a particularly low content of thinners with a boiling point of less than 200 °C, in particular less than 1% by weight.

[0079] The epoxy resin coating preferably contains a low content of diluents with a boiling point of more than 200 °C, in particular less than 20% by weight, preferably less than 15% by weight.

[0080] Suitable surface-active additives include, in particular, defoamers, deaerators, wetting agents, dispersants, leveling agents, or dispersed paraffin wax. The epoxy resin coating preferably contains a combination of such additives.

[0081] Suitable stabilizers are especially stabilizers against UV radiation or heat.

[0082] The epoxy resin coating may contain other auxiliary materials and additives, in particular Pigments, in particular titanium dioxide, iron oxides or chromium(III) oxide, 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, other reactive diluents, in particular 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 such as in particular ethylene, propylene, butylene, isobutylene, isoprene,Vinyl acetate or alkyl (meth)acrylates, or chlorosulfonated polyethylenes, fluorine-containing polymers or sulfonamide-modified melamines, rheology modifiers, in particular anti-settling agents, adhesion promoters, in particular organoalkoxysilanes, flame-retardant substances, in particular 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(dibromonorbornandicar-boximide), 1,2-bis(tribromophenoxy)ethane, tris(2,3-dibromopropyl)isocyanurate, tribromophenol, hexabromocyclododecane,Bis(hexachlorocyclopentadieno)cyclooctane or chlorinated paraffins, other conductive substances, in particular doped mineral fillers, metal powders, carbon fibers, carbon black, graphite or ionic liquids, or other additives, in particular film-forming aids or biocides.

[0083] The epoxy resin coating preferably comprises at least two components, which are stored in separate containers and mixed together only shortly before application.

[0084] The resin component contains at least the epoxy liquid resin and, if necessary, other compounds containing epoxy groups.

[0085] The hardener component contains the amine of formula (I) and optionally other compounds reactive with epoxy groups.

[0086] The additional ingredients, in particular the carbon nanotubes, can be present as part of the resin and / or hardener component. Carbon nanotubes dispersed in a liquid containing epoxy groups are preferably a component of the resin component.

[0087] Preferably, an epoxy resin coating comprising a resin component containing at least one epoxy liquid resin, carbon nanotubes, at least one defoamer, optionally pigments and fillers and optionally at least one thinner, in particular benzyl alcohol, and a hardener component comprising at least one amine of the formula (I), optionally further amines, optionally at least one thinner, in particular benzyl alcohol, and optionally at least one accelerator.

[0088] Preferably, the epoxy resin coating is not water-based and contains only a low water content, preferably less than 5% by weight, especially less than 1% by weight. Such a coating is particularly resistant to moisture.

[0089] However, it is also possible for the epoxy resin coating to contain a higher water content. In particular, the resin component or the hardener component, or both, can be water-based.

[0090] Particularly preferred is an epoxy resin coating containing 0.001 to 0.05 wt% carbon nanotubes, less than 1 wt% diluent with a boiling point below 200 °C, and less than 5 wt% water based on the entire coating.

[0091] Such a coating is easy to apply, causes hardly any emissions and enables floor coatings with particularly high resistance to moisture and good electrical conductivity.

[0092] In a preferred embodiment, the epoxy resin coating is pigmented and contains, based on the entire coating, 20 to 70% by weight, in particular 30 to 60% by weight, of calcium carbonate, quartz flour, quartz sand or a combination thereof.

[0093] Such a coating enables particularly robust floor coatings in decorative colors, in which the fillers hardly sink during application and curing and thus hardly cause any inhomogeneities in the coating.

[0094] In a further preferred embodiment, the epoxy resin coating is transparent and contains, based on the entire coating 0.001 to 0.01% by weight of carbon nanotubes, 1 to 3% by weight of zinc oxide, in particular aluminum-doped zinc oxide, and in particular less than 0.1% by weight of fillers or pigments other than carbon nanotubes and zinc oxide.

[0095] Such a coating enables high transparency, whereby particularly aesthetic effects can be achieved, especially in combination with electrically conductive decorative quartz sand.

[0096] In the epoxy resin coating, the ratio of the number of groups reactive towards epoxy groups to the number of epoxy groups is preferably in the range of 0.5 to 1.5, in particular 0.7 to 1.2.

[0097] The resin and hardener components of the epoxy resin composition are stored in separate containers. A bucket, hobbock, barrel, bag, or can are particularly suitable containers for storing the resin or hardener components. The components are storable, meaning they can be kept for several months up to a year or longer before use without their properties changing to an extent relevant to their intended use. To apply the epoxy resin coating, the components are mixed together shortly 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 reactive towards 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 component and the hardener component is usually in the range of 1:10 to 20:1, preferably 1:1 to 10:1.

[0098] The components are mixed using a suitable process; this can be done continuously or batchwise. If mixing is not performed immediately prior to application, care must be taken to ensure that the time between mixing the components and application is not too long, and that application is completed within the pot life. Mixing is performed primarily at ambient temperature, which is typically in the range of approximately 5 to 40°C, preferably approximately 10 to 35°C.

[0099] When the two components are mixed, curing begins through a chemical reaction. The primary and secondary amino groups, and any other epoxy-reactive groups present, react with the epoxy groups, causing their ring opening (addition reaction). As a result of this reaction, the epoxy resin coating polymerizes and thus cures.

[0100] Curing preferably occurs at ambient temperature and typically takes several hours to several days. The duration depends, among other things, on the temperature, the reactivity of the components, their stoichiometry, and the presence of accelerators.

[0101] In the freshly mixed state, the epoxy resin coating has a low viscosity. The viscosity 5 minutes after mixing the components at 20°C is preferably in the range of 100 to 4,000 mPa s, preferably 200 to 3,000 mPa s, in particular 300 to 2,000 mPa s, measured using a cone-and-plate viscometer at a shear rate of 10 s -1< .

[0102] The epoxy resin coating is applied to at least one substrate, the following being particularly suitable: Concrete, mortar, cement screed, fiber cement, brick, tiles, gypsum, natural stones such as granite or marble, or sand, in particular electrically conductive quartz sand; 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; plastics such as rigid and soft PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM or EPDM, each untreated or surface-treated, for example by means of plasma, corona or flames; Fiber-reinforced plastics, such as carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GRP) and sheet molding compounds (SMC);Coated or painted substrates, in particular painted tiles, painted concrete, powder-coated metals or alloys; coatings, paints or varnishes, in particular coated floors which are covered with another floor covering layer.

[0103] 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.

[0104] The freshly mixed epoxy resin coating is applied to a substrate within its pot life in a layer thickness of approximately 0.1 to approximately 5 mm, typically at ambient temperature. Application is typically carried out by pouring the coating onto the substrate to be coated and then spreading it evenly using a squeegee or rubber squeegee, for example. Application can also be performed with a brush or roller. Upon curing, the resulting films typically produce homogeneous, even, glossy, non-tacky, pigmented, or transparent films of high hardness and robustness, which exhibit good adhesion to a wide variety of substrates.

[0105] A further object of the invention is the cured, electrically conductive epoxy resin coating obtained from the mixed epoxy resin coating.

[0106] After curing, the epoxy resin coating has an electrical conductivity in a range that is suitable as a component of an electrostatically dissipative floor system.

[0107] In particular, after curing, the epoxy resin coating has an electrical resistance to earthing in a layer thickness in the range of 0.3 to 3 mm, determined according to DIN EN 61340-4-1, in the range of > 5 10 4< Ohm and < 10 9< Ohm.

[0108] If the cured epoxy resin coating is transparent, it preferably has an absorption at 665 nm, determined by UV-Vis spectroscopy, of at most 0.7, preferably at most 0.6, and in particular at most 0.5, at a layer thickness of 0.5 mm on glass. Such a coating is particularly suitable as a transparent sealant for electrostatically conductive floors, especially for floors sprinkled with electrically conductive quartz sand, whereby the color and structure of the sand remain clearly visible and a highly aesthetic surface is achieved.

[0109] The epoxy resin coating according to the invention is preferably used as a component of an electrostatically dissipative flooring system. Such a flooring system is particularly suitable for installation in production halls or rooms where uncontrolled electrostatic discharges are problematic. These are particularly suitable for rooms where electronic components are manufactured, stored, or used, or where highly sensitive measuring systems are used, or where flammable liquids or explosives are handled or stored, as well as in air-conditioned rooms with particularly low humidity and particularly few particles in the atmosphere, such as clean rooms, radiological facilities, or operating rooms.

[0110] A further object of the invention is thus an electrostatically conductive floor system, comprising from bottom to top (i) at least one substrate, (ii) optionally at least one epoxy resin primer, (iii) at least one electrical conduction system connected to an earthing system, (iv) at least one electrically conductive epoxy resin coating as previously described, (v) optionally at least one interspersed filler, and (vi) optionally at least one sealant.

[0111] The electrostatically conductive floor system preferably has a total electrical resistance to earthing determined according to DIN EN 61340-4-1 in the range of > 5·10 4< Ohm and < 10 9< Ohm.

[0112] Particularly suitable as substrate (i) are concrete, optionally pretreated by grinding, sandblasting, or shot blasting, or mortar, cement screed, fiber cement, brick, tile, gypsum, natural stone such as granite or marble, asphalt, or a repair or leveling compound based on PCC (polymer-modified cement mortar) or ECC (epoxy resin-modified cement mortar). Concrete, mortar, or cement screed is preferred.

[0113] The substrate is preferably coated with at least one epoxy resin primer (ii). This is preferably low-viscosity and largely free of fillers. Its primary purpose is to consolidate the substrate, close any pores, and ensure good adhesion between the substrate and the subsequent layers. The primer is typically applied to the substrate using a brush, roller, or rubber squeegee. It is applied in one or more layers, typically in a quantity in the range of 0.2 to 0.5 kg / m². Suitable commercially available products include Sikafloor®<-150, Sikafloor®<-151, Sikafloor®<-160, or Sikafloor®<-161 (all from Sika).

[0114] If the substrate is uneven, an epoxy resin composition filled with sand can be applied after priming to level the surface.

[0115] A grounded conducting system (iii) is laid on the substrate, which may have been primed and leveled, if necessary. For grounding, holes are preferably drilled into the ground and protruding metal screws are secured into them. A network of copper wires or copper strips is preferably laid on the screws, with these wires or copper strips in contact with the screws, for example, via attached metal washers. The equipment for this and a detailed installation description are provided, for example, in the commercially available Sikafloor ®< conducting set (from Sika). Depending on the spacing of the copper wires or strips and the grounding screws and the type of coating (iv), a so-called conductive film is also applied to this installation to ensure electrical conduction between the copper wires or strips.Highly conductive epoxy resin coatings, such as Sikafloor ®< -220 W Conductive (from Sika), are particularly suitable as conductive films.

[0116] Preferably, the electrical conduction system comprises at least one grounded copper wire or a grounded copper strip and optionally at least one electrically conductive film in contact therewith with an electrical resistance of < 10 4 < Ohm.

[0117] At least one electrically conductive epoxy resin coating (iv) comprising carbon nanotubes and at least one amine of formula (I) is then applied to the electrical conduction system and cured, as described above. The epoxy resin coating (iv) can be transparent or pigmented, as described above. It is applied to the conduction system in one or more layers, in particular in a layer thickness in the range of 0.1 to 5 mm, preferably 0.2 to 3 mm. It is preferably applied in only one layer in an amount in the range of 0.2 to 3 kg / m 2 , preferably 0.3 to 2.5 kg / m 2 .

[0118] The electrically conductive epoxy resin coating can be filled with a filler (v) sprinkled in during the pot life. Quartz powder and / or quartz sand are particularly suitable fillers. The filler can be sized so that it mostly sinks into the coating and solidifies the epoxy resin coating, or it can be sanded in excess, resulting in a sanded, rough surface after curing and removal of the excess sand.

[0119] To produce a sanded, rough surface, at least one electrically conductive quartz sand is preferably used.

[0120] Particularly suitable as electrically conductive quartz sand is quartz sand coated with an electrically conductive synthetic resin, which in particular has a grain size in the range of 0.1 to 1.3 mm. Such quartz sands are commercially available, for example, as Granucol® Conduct 2.0 (from Dorfner).

[0121] At least one sealant (vi) is then optionally applied to the electrically conductive epoxy resin coating, which may be sprinkled with filler. A particularly suitable sealant is a transparent, electrically conductive epoxy resin coating, which contains, in particular, carbon nanotubes and at least one amine of formula (I), and preferably additionally a zinc oxide, in particular an aluminum-doped zinc oxide.

[0122] The seal is applied in particular in an amount in the range of 0.1 to 1 kg / m 2< , preferably 0.2 to 0.7 kg / m 2< .

[0123] In a preferred embodiment of the flooring system, the electrically conductive epoxy resin coating (iv) is pigmented and has a layer thickness in the range of 0.1 to 5 mm, in particular 0.2 to 3 mm. In this case, the flooring system preferably contains no excess filler scattered on the surface and no sealant. The pigmented epoxy resin coating (iv) therefore preferably forms the topmost layer of the flooring system. It is particularly important that this surface is well ventilated and thus particularly even to meet high aesthetic standards.

[0124] In this embodiment, the electrical conductivity of the epoxy resin coating (iv) is so reliable and good that the so-called conductive film, such as Sikafloor ®< -220 W Conductive (from Sika), can be omitted in the grounded electrical conduction system (iii). This means that an entire work step, including the waiting time for the conductive film to cure, is eliminated, which is particularly advantageous.

[0125] In this embodiment, the pigmented electrically conductive epoxy resin coating (iv) is preferably applied directly to at least one grounded copper wire or at least one grounded copper strip, and there is no electrically conductive film therebetween.

[0126] In a further preferred embodiment of the invention, the electrically conductive epoxy resin coating (iv) is sprinkled with an excess of electrically conductive quartz sand and coated with a transparent sealant. The epoxy resin coating (iv) is preferably present in a layer thickness in the range of 0.3 to 1 mm. It is preferably transparent and preferably contains a zinc oxide, in particular an aluminum-doped zinc oxide. The transparent sealant is preferably also an electrically conductive epoxy resin coating and preferably contains carbon nanotubes and at least one zinc oxide.

[0127] The floor system according to the invention is preferably a component of a building or a room within a building. In particular, the floor system is present wherever uncontrolled discharges can cause damage. These include, in particular, rooms where electronic components are manufactured, stored, or used, or where highly sensitive measuring systems are used, or where flammable liquids or explosives are handled or stored, as well as, in particular, air-conditioned rooms with particularly low humidity and particularly few particles in the atmosphere, such as clean rooms, radiological facilities, or operating rooms. Examples

[0128] The following are exemplary embodiments intended to further illustrate the described invention. Of course, the invention is not limited to these described exemplary embodiments.

[0129] "AHEW" stands for amine hydrogen equivalent weight.

[0130] "EEW" stands for epoxy equivalent weight.

[0131] The "standard climate" ("NK") is defined as a temperature of 23±1°C and a relative humidity of 50±5%.

[0132] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH. Substances and abbreviations used:

[0133] CNT Dispersion 10%: Dispersion of 10 wt% single-wall carbon nanotubes in alkyl glycidyl ether, EEW 266 g / mol (Tuball ®< Matrix Beta 207, from OCSiAl) Araldite ®< GY 250: Bisphenol A diglycidyl ether, EEW 187 g / mol (from Huntsman) Araldite ®< DY-P: p-tert.butylphenyl glycidyl ether, EEW 225 g / mol (from Huntsman) Araldite ®< DY-H: Hexanediol diglycidyl ether, EEW 147 g / mol (from Huntsman) Chalk Omyacarb ®< 10 GU (from Omya) Al-doped ZnO aluminum-doped zinc oxide (ZnO-23K, from Itochu) B-EDAN-benzyl-1,2-ethanediamine, AHEW 50.1 g / eq, prepared as described below IPDA1-Amino-3-aminomethyl-3,5,5-trimethylcyclohexane, AHEW 42.6 g / eq (Vestamin ®< IPD, from Evonik) MXDA1,3-Bis(aminomethyl)benzene, AHEW 34 g / Eq (from Mitsubishi Gas Chemical) TMD2,2(4),4-Trimethylhexamethylenediamine, AHEW 39.6 g / Eq (Vestamin ®< TMD, from Evonik) D-230Polyoxypropylenediamine, average molecular weight 230 g / mol, AHEW 60 g / mol (Jeffamine ®< D-230, from Huntsman) Adduct-A1Adduct of IPDA, MXDA and Araldite ®< GY 250 in benzyl alcohol, AHEW 231 g / eq, prepared as described below Adduct-B1Adduct of B-EDA and Araldite ®< GY 250, AHEW 116.3 g / eq, prepared as described below Ancamine ®< K542,4,6-Tris(dimethylaminomethyl)phenol (from Air Products) Sikafloor ®< -150:2-component epoxy primer (from Sika) Sikafloor ®< -151:2-component Epoxy resin primer (from Sika) Sikafloor ®< -220 W Conductive: 2-component, water-based, electrically highly conductive, black epoxy resin coating Conductive quartz sand: Electrically conductive quartz sand 0.3 to 0.8 mm coated with synthetic resin (Granucol ®< Conduct 2.0, from Dorfner). N-Benzyl-1,2-ethanediamine (B-EDA):

[0134] 180.3 g (3 mol) of 1,2-ethanediamine were initially charged at room temperature, mixed with a solution of 106.0 g (1 mol) of benzaldehyde in 1200 ml of isopropanol, and stirred for 2 hours. The mixture was then hydrogenated at 80°C, 80 bar hydrogen pressure, and a flow rate of 5 ml / min on a continuously operating hydrogenation apparatus with a Pd / C fixed-bed catalyst. The hydrogenated solution was concentrated on a rotary evaporator at 65°C, removing unreacted 1,2-ethanediamine, water, and isopropanol. The resulting reaction mixture was purified by distillation at 80°C under vacuum. A colorless liquid was obtained with an N-benzyl-1,2-ethanediamine content of > 97%, determined by GC. Adduct-A1:

[0135] 57.3 g of IPDA, 42.5 g of MXDA, and 318.8 g of benzyl alcohol were heated to 80 °C, and 81.3 g of Araldite ®< GY 250 were slowly added with thorough stirring, maintaining the reaction mixture temperature between 70 and 90 °C. A clear, slightly yellowish liquid with a viscosity of 45 mPa s at 20 °C was obtained. Adduct B1:

[0136] 55.0 g of N-benzyl-1,2-ethanediamine (B-EDA) was heated to 80 °C and 45.0 g of Araldite ®< GY 250 were slowly added with vigorous stirring, maintaining the reaction mixture temperature between 70 and 90 °C. A clear, slightly yellowish liquid with a viscosity of 262 Pa s at 20 °C was obtained.

[0137] The viscosity of the adducts was determined as described for Example 1. Production of electrically conductive epoxy resin coatings: Examples 1 to 3 (pigmented coating in light grey):

[0138] For these examples, a resin component was prepared by mixing the following ingredients using a centrifugal mixer (SpeedMixer™< DAC 150, FlackTek Inc.) and storing it in an atmosphere free from moisture: 125.9 parts by weight Araldite ®< GY 250, 25.2 parts by weight Araldite ®< DY-P, 11.5 parts by weight Araldite ®< DY-H, 0.27 parts by weight CNT dispersion 10%, 231.0 parts by weight chalk, 12.7 parts by weight benzyl alcohol, 5.6 parts by weight additives / defoamers, 45.8 parts by weight pigment paste light grey.

[0139] For each example, the ingredients of the hardener component listed in Table 1 were mixed in the specified amounts (in parts by weight) using the centrifugal mixer and stored under exclusion of moisture.

[0140] The two components were then processed into a homogeneous liquid using the centrifugal mixer and immediately tested as follows: The viscosity was measured 5 minutes after mixing the resin and hardener components using a cone-plate viscometer at a shear rate of 10 s -1< and a temperature of 20 °C. Setting time was determined by moving a freshly mixed amount of approximately 3 g in a standard atmosphere with a spatula at regular intervals until the mass gelled. Shore D Hardness was determined according to DIN 53505 on two cylindrical test specimens (20 mm diameter, 5 mm thickness), one stored under standard conditions and one at 8°C and 80% relative humidity. Hardness was measured after 1 day, 2 days, and 7 days, respectively.

[0141] A chipboard was primed with 0.3 kg / m 2 Sikafloor ® -150, stored for 24 hours under standard conditions, then 0.1 kg / m 2 Sikafloor ® -220 W Conductive was applied, and the board was stored for another 24 hours under standard conditions. 1.3 kg / m 2 of the respective epoxy resin coating was applied to the coated board, spread with a squeegee, and then rolled with a spiked roller while still liquid to remove air. Course and the Ventilationobserved. The leveling was described as "very good" if the liquid coating quickly leveled out after a few strokes of the squeegee and flowed nicely into the corners. The leveling was described as "ok" if the liquid coating required significantly more strokes of the squeegee to spread, had to be spread into the corners, and then slowly leveled out. The deaeration was described as "good" or "very good" if the finely dispersed air combined to form larger bubbles when rolled with the spiked roller, these bubbles reliably burst on the surface, and almost no or no further bubbles rose after rolling with the spiked roller.The deaeration was described as "incomplete" if, even after rolling with the spiked roller, further finely distributed air rose, remained on the surface of the hardening and thus increasingly viscous and finally gelling coating, thus creating a slightly uneven, not entirely even surface.

[0142] The aspect The surface was assessed on the coated chipboard after a curing time of 7 days. A "beautiful" surface was defined as having a glossy, non-sticky finish without streaks or cloudiness. A "even" surface was defined as having a smooth finish without bumps or craters.

[0143] The electric Resistance was measured at 8 points on the coated chipboard of Example 1 after a curing time of 7 days in standard climate against the ground according to DIN EN 61340-4-1.

[0144] The results are shown in Table 1.

[0145] The examples marked "(Ref.)" are comparative examples. Table 1: Composition and properties of examples 1 to 3. "nb" stands for "not determined" Example 1 2 3 (Ref.) Resin component: 458.0 458.0 458.0 Hardener component: B-EDA 6.0 12.6 - IPDA 15.6 10.0 20.7 MXDA 9.1 9.1 9.1 Adduct-A1 57.3 57.3 57.3 Benzyl alcohol 7.7 7.7 7.7 Ancamine ®< K54 8.0 8.0 8.0 Viscosity (5') [Pa·s] 1.5 1.4 1.8 Setting time [h:min] 2:35 2:25 2:45 Shore D (1d NK) 52 54 65 (2d NK) 70 62 72 (7d NK) 72 75 76 Shore D (1d 8° / 80%) 31 31 26 (2d 8° / 80%) 61 62 61 (7d 8° / 80%) 73 74 73 Course very good very good OK Ventilation good very good incomplete aspect beautiful, even beautiful, even nice, a bit uneven Resistance [Ohm] Mean: 1.1·10 6< nb nb Minimum value: 2.4·10 5< Maximum value: 2.1·10 6< Examples 4 and 5 (transparent coating or seal):

[0146] For these examples, a resin component was prepared by mixing the following ingredients using a centrifugal mixer and storing them away from moisture: 185.6 parts by weight Araldite ®< GY 250, 0.04 parts by weight CNT dispersion 10%, 4.2 parts by weight Al-doped ZnO, 4.8 parts by weight additives / defoamers 15.4 parts by weight benzyl alcohol.

[0147] For each example, the ingredients of the hardener component listed in Table 2 were mixed in the specified amounts (in parts by weight) using the centrifugal mixer and stored under exclusion of moisture.

[0148] The two components were then processed into a homogeneous liquid using a centrifugal mixer and tested as follows: Viscosity, gel time and Shore D were tested as described for Example 1.

[0149] A chipboard was primed with 0.3 kg / m 2< Sikafloor ®< -150, stored for 24 hours in standard climate, then 0.1 kg / m 2< Sikafloor ®< -220 W Conductive was applied and the board was stored for another 24 hours in standard climate. 0.5 kg / m 2< of the respective example was applied to the coated board, spread with a squeegee and then rolled over with a nylon roller while still liquid. Course and the Ventilationassessed as described for Example 1.

[0150] To assess the transparency A film with a thickness of 500 µm was applied to a glass plate and stored under standard conditions for 7 days. The glass plate was then placed on a printed newspaper, and the visibility of the newspaper's writing through the coated glass plate was assessed. Transparency was designated "high" if the writing was clearly and sharply visible. Transparency was designated "medium" if the writing was clearly visible but blurred.

[0151] The measure of transparency continued to be the absorption by UV-Vis spectroscopy. For this purpose, the absorption at 665 nm (red) was determined on the glass plate coated to assess transparency using a UV-Vis instrument (Cary 60 from Agilent Technologies).

[0152] The aspect and the electric Resistancewere determined on the coated chipboard as described for Example 1.

[0153] The results are shown in Table 2.

[0154] The examples marked "(Ref.)" are comparative examples. Table 2: Composition and properties of examples 4 and 5 Example 4 5 (Ref.) Resin component: 210.0 210.0 Hardener component: B-EDA 4.3 - Adduct-B1 2.9 - IPDA 22.3 27.0 TMD 7.7 7.7 D-230 10.3 10.3 Benzyl alcohol 24.0 24.0 Viscosity (5') [Pa·s] 0.82 0.84 Setting time [h:min] 2:30 2:40 Shore D (1d NK) 73 72 (2d NK) 79 78 (7d NK) 79 79 Shore D (1d 8° / 80%) 12 8 (2d 8° / 80%) 64 64 (7d 8° / 80%) 79 73 Course very good very good Ventilation very good very good aspect beautiful, even, beautiful, even transparency high medium Absorption at 665 nm 0.45 0.51 Resistance [Ohm] Mean: 1.5·10 7< nb Minimum value: 3.0·10 6< Maximum value: 3.3·10 8< Production of electrostatically dissipative floor systems: Example 6:

[0155] An area of 55 m² of polished concrete flooring was installed indoors with an electrostatically dissipative flooring system. During installation, the air temperature was between 25 and 30 °C and the humidity was between 35 and 40%.

[0156] First, a layer of Sikafloor ®< -151 was rolled on as a primer in a quantity of 0.4 kg / m 2< and allowed to cure for 24 hours.

[0157] Earthing points and copper strips from a Sikafloor ®< conductive set were then installed on the prepared floor according to the instructions.

[0158] Then 2.0 kg / m 2< of the electrically conductive epoxy resin coating from Example 1 applied, spread with a rubber squeegee, and then rolled with a spiked roller. The epoxy resin coating showed excellent flow and very good air release. The resulting gray-pigmented surface was even, hard, glossy, tack-free, and free of streaks or cloudiness.

[0159] The electrical resistance of the finished floor system to the earthing system was measured at 30 points according to DIN EN 61340-4-1. The range of measured values is given in Table 3. Example 7:

[0160] An area of 55 m² of polished concrete flooring indoors was covered with an electrostatically dissipative flooring system. During installation, the substrate temperature was between 14 and 17 °C, the air temperature between 13 and 19 °C, and the humidity between 49 and 66%.

[0161] First, a layer of Sikafloor ®< -151 was rolled on as a primer in a quantity of 0.4 kg / m 2< and allowed to cure for 24 hours.

[0162] Subsequently, earthing points and copper strips from a Sikafloor ®< conductive set were installed on the prepared floor according to the instructions, followed by the Sikafloor ®< -220 W Conductive coating, which was rolled on as a conductive film in a quantity of 0.1 kg / m 2<.

[0163] After 24 hours of curing, 0.5 kg / m 2< of the transparent, electrically conductive epoxy resin coating was Example 4applied. The material was poured on, spread with a rubber squeegee, and then rolled over with a roller. Within 30 minutes of application, this layer was sprinkled with an excess of 3 kg / m² of conductive quartz sand. After a curing time of 24 hours, the excess sand was removed with a broom and vacuum cleaner.

[0164] The sanded surface was then coated with the electrically conductive epoxy resin coating made of Example 4 sealed transparently by spreading it in a quantity of 0.4 kg / m 2< using a rubber squeegee and then rolling it over with a textured roller.

[0165] The sealer spread easily over the sanded surface and, after rolling, presented a smooth surface free of streaks, bubbles, craters, or other inhomogeneities. After curing, the floor system exhibited a highly aesthetic, even, slightly grayish, hard, tack-free, transparent surface through which the color of the sand was clearly visible.

[0166] The electrical resistance of the finished floor system to the earthing system was measured at 30 points according to DIN EN 61340-4-1. The range of measured values is given in Table 3. Table 3: Structure and electrical resistance of examples 6 and 7 Example 6 7 Substrate: ground concrete Primer: Sikafloor ®< -151 Sikafloor ®< -151 Guidance system: Sikafloor ®< Guide set Sikafloor ®< Conductive set and Sikafloor ®< -220 W Conductive Epoxy resin coating: pigmented coating made of Example 1 transparent coating made of Example 4 sprinkled with: - conductive quartz sand Sealing: - transparent coating made of Example 4 Resistance to ground: [Ohm] 7.9·10 6< to 1.2·10 7< 1.2·10 5< to 2.4·10 5<

Claims

1. Use of a combination of carbon nanotubes and at least one amine of the formula (I)         Z-NH-A-NH-CH2-Y     (I) where A is a divalent C2 to C15 alkylene, cycloalkylene or arylalkylene radical optionally containing one or more nitrogen atoms or ether groups, and Z is H or ---CH2-Y, and Y is H or a C1 to C12 alkyl, cycloalkyl, arylalkyl or aryl radical, where the amine of the formula (I) contains a total of at least 8 carbon atoms, for production of an electrically conductive epoxy resin coating.

2. Use according to Claim 1, characterized in that the carbon nanotubes are present in an amount in the range from 0.001% to 0.1% by weight, especially 0.001% to 0.05% by weight, based on the overall epoxy resin coating.

3. Use according to either of Claims 1 and 2, characterized in that A is 1,2-ethylene, Z is H and Y is phenyl.

4. Use according to any of Claims 1 to 3, characterized in that the amine of the formula (I) is present in such an amount that at least 5% of all amine hydrogens present in the epoxy resin coating come from amines of the formula (I).

5. Electrically conductive epoxy resin coating obtained from the use according to any of Claims 1 to 4, comprising - at least one liquid epoxy resin, - at least one amine of the formula (I), - carbon nanotubes, and - at least one further constituent selected from the list consisting of further amines, accelerators, fillers, thinners, surface-active additives and stabilizers.

6. Epoxy resin coating according to Claim 5, characterized in that 5% to 50% of all amine hydrogens present come from amines of the formula (I) and at least one further amine having at least four aliphatic amine hydrogens is present.

7. Epoxy resin coating according to either of Claims 5 and 6, characterized in that it contains less than 5% by weight of water based on the overall coating.

8. Epoxy resin coating according to any of Claims 5 to 7, characterized in that it contains - 0.001% to 0.05% by weight of carbon nanotubes, - less than 1% by weight of thinner having a boiling point of less than 200°C, and - less than 5% by weight of water, based on the overall coating.

9. Epoxy resin coating according to any of Claims 5 to 8, characterized in that it has been pigmented and, based on the overall coating, contains 20% to 70% by weight of calcium carbonate, ground quartz, quartz sand or a combination thereof.

10. Epoxy resin coating according to any of Claims 5 to 8, characterized in that it is transparent and contains - 0.001% to 0.01% by weight of carbon nanotubes, - 1% to 3% by weight of zinc oxide, especially aluminium-doped zinc oxide, and - especially less than 0.1% by weight of fillers or pigments other than carbon nanotubes and zinc oxide, based on the overall coating.

11. Cured electrically conductive epoxy resin coating obtained from the mixed epoxy resin coating according to any of Claims 5 to 10.

12. Electrostatically dissipative floor system comprising, from the bottom upward, (i) at least one substrate, (ii) optionally at least one epoxy resin primer, (iii) at least one grounded electrical conductor system, (iv) at least one electrically conductive epoxy resin coating according to Claim 11, (v) optionally at least one distributed filler, and (vi) optionally at least one seal.

13. Floor system according to Claim 12, characterized in that electrical resistance to ground, determined to DIN EN 61340-4-1, is in the range of > 5·104 ohms and < 109 ohms.

14. Floor system according to either of Claims 12 and 13, characterized in that the electrical conduction system comprises at least a grounded copper wire or a grounded copper ribbon and optionally at least one electrically conductive foil which is in contact therewith and has an electrical resistance of < 104 ohms.

15. Floor system according to any of Claims 12 to 14, characterized in that the electrically conductive epoxy resin coating has been pigmented and has a layer thickness in the range from 0.1 to 5 mm, especially 0.2 to 3 mm.

16. Floor system according to Claim 15, characterized in that the electrically conductive epoxy resin coating is applied directly to at least one grounded copper wire or at least one grounded copper ribbon and there is no electrically conductive foil in between.

17. Floor system according to any of Claims 12 to 14, characterized in that an excess of electrically conductive quartz sand is scattered over the electrically conductive epoxy resin coating and covered with a transparent seal.