Accelerated curing multi-component epoxy resin composition

Abstract

The present invention relates to a multi-component epoxy resin composition comprising: - a first component comprising: - at least one epoxy resin having an average of two or more epoxy groups per molecule; - optionally, at least one reactive diluent having one epoxy group per molecule; - optionally, further additives; and - a second component comprising: - at least one amine curing agent for the epoxy resin; - optionally, further additives; and - a third component comprising: - an aqueous solution of at least one metal salt (wherein the solution contains between 20 and 80 parts by weight, preferably between 30 and 70 parts by weight, and particularly between 40 and 60 parts by weight, based on 100 parts by weight of water in the aqueous solution). Herein, the weight ratio of the second component to the third component is between 100:0.3 and 100:10, preferably between 100:1 and 100:5. By combining a water-based curing-accelerating third component with a general two-component epoxy resin composition, a significant acceleration of curing is achieved in the two-component epoxy resin composition without the need for heating, and without adversely affecting the properties of the cured epoxy resin composition.

Description

[Technical Field]

[0001] The present invention relates to multi-component epoxy resin compositions, their use as adhesives, sealants, or coatings, the use of additional components to accelerate the curing of two-component epoxy resin compositions, and methods for accelerating the curing of multi-component epoxy resin compositions. [Background technology]

[0002] Epoxy resins provide an ideal matrix for preparing adhesives, sealants, or coatings due to their excellent properties, such as superior chemical resistance, high thermal stability, good workability, and high adhesive strength. Therefore, epoxy adhesives are used in a wide variety of fields, particularly in biochemistry, construction, marine, aerospace, and refurbishment. Several types of curing agents exist for curing epoxy resins. A primary distinction can be made between low-temperature and high-temperature curing agents. High-temperature curing agents require heating to complete crosslinking within a reasonable time. Typical examples of high-temperature curing agents include polycarboxylic acids and their anhydrides, polycarboxylic acid polyhydrazides, polyhydric phenols, and dicyandiamides. On the other hand, common low-temperature curing agents that do not usually require heating include polyamines, such as alkyleneamine polymers. Other highly effective fast-curing curing agents include imidazoles, thiols, amines (mostly alicyclic amines, aliphatic amines, and low molecular weight polyamide compounds), and complexes (e.g., boron trifluoride amines). The curing speed of amine curing agents, from fastest to slowest, is as follows: aliphatic amines > alicyclic amines > low molecular weight polyamides > aromatic amines. In epoxy-based systems, the curing process of the selected resin and curing agent, along with their mechanical and thermal properties, determines the workability and end-use.

[0003] Particularly in the construction market, and especially at low temperatures, it is necessary to further accelerate the curing process of epoxy-based materials to reduce both manufacturing time and downtime.

[0004] To increase the curing speed of epoxy resins, compounds called accelerators are typically used to reduce the curing time of the system. Current solutions include, for example, adding or generating hydroxyl group-containing substances in situ, or increasing the curing temperature through either an exothermic process within the composition or external heating.

[0005] The higher the temperature, the faster the hardening process; the lower the temperature, the slower the process.

[0006] Phenolic compounds, such as hydroxybenzene and cresol, are typically used as accelerators for the low-temperature curing of epoxy resins. These compounds have the advantage of readily dissolving at ambient temperature in the most commonly used liquid amino curing agents and liquid epoxy resins, and also exhibit good accelerating activity. However, typical phenolic accelerators impart odor and toxicity to the resin, which hinders their use in certain applications. Another accelerator used, benzoyl alcohol, is considered a semi-volatile organic compound (SVOC). SVOCs tend to have higher molecular weights and boiling points than the notorious VOCs, meaning they are less likely to vaporize at room temperature. However, this does not mean they are less dangerous. In fact, if they are present in adhesives, even at extremely low concentrations, they will not be classified as low-emission products under EMICODE certification (a new standard in the construction market and becoming a central factor in consumer purchasing decisions).

[0007] To overcome these drawbacks, the addition of other curing catalysts or accelerators to epoxy compositions has been studied and documented in the literature.

[0008] For example, U.S. Patent No. 4,668,736A teaches that the curing of epoxy resin compositions can be accelerated by using metal salt catalysts, particularly calcium nitrate, lanthanum nitrate, and other metal salts having calcium, strontium, or barium cations and perchlorate or trifluoromethanesulfonate anions. These salts are added either in solid form or dissolved in a solvent such as ethylene glycol ethyl ether, and are suggested in the publication as a good solution for accelerating the curing reaction of epoxy compositions based on glycidyl ether epoxide group-containing resins and amino-terminated curing agents. However, the addition of solvents to epoxy resin compositions is often undesirable because they can affect the VOC rating and may alter the properties of the composition, for example, by imparting a plasticizing effect or migrating to the surface of the composition and reducing its adhesive properties.

[0009] U.S. Patent Application Publication No. 2003 / 130481A1 discloses a kit for use in forming an epoxy gel coat, the kit comprising a curing agent component containing an epoxy curing agent, a resin component containing a liquid epoxy resin, and an aqueous accelerator component consisting of an aqueous solution of an inorganic nitrate, such as ammonium, lithium, sodium, potassium nitrate, or further nitrates. Specifically, the accelerator component is mixed with the resin component, which is then preferably mixed with 2-4% by weight of nitrate and 1-2% by weight of water. The disclosure teaches that the use of the accelerator reduces the gelation time of the epoxy gel coat at room temperature, but there is no significant change in the Tg of the cured gel coat.

[0010] U.S. Patent Application Publication No. 2021 / 332181A1 discloses a curing agent for epoxy resins based on a specific amine mixture. Among the general teachings of the specification, accelerators that may be included in the curing agent are described. Of these, calcium nitrate is particularly discussed, which is advantageously used in combination with 2,4,6-tris(dimethylaminomethyl)phenol, and is preferably used in the form of an aqueous solution containing 20% ​​to 70% by weight of calcium nitrate. The advantages of using this combination with the described accelerator are rapid curing, especially at low temperatures, and high hardness of the cured composition.

[0011] European Patent No. 0169066B1 discloses a two-component epoxy resin composition comprising a first component containing a glycidyl ether epoxide group-containing compound, a second component containing an amino-terminated aliphatic polyether curing agent, and at least one of the two components comprising 1 to 10 parts by weight of a metal salt catalyst selected from calcium nitrate, lanthanum nitrate, and metal salts having cations of calcium, strontium, or barium and anions of perchlorates or trifluoromethanesulfonates. The addition of these salts results in an acceleration of the curing rate, and the document teaches that anhydrous metal salt catalysts are preferred because the presence of water, whether for hydration or separately included in the composition, often reduces the curing rate as measured in relation to exothermic reactions.

[0012] Japanese Patent Publication No. 7182699B2 discloses a curing agent for epoxy resin compositions, the latter being particularly suitable for chemically securing construction elements in boreholes. The curing agent contains at least one salt selected from the group consisting of nitrates, nitrites, halogen salts, and trifluoromethanesulfonates, which functions as an accelerator for curing the epoxy resin composition. In exemplary experimental embodiments, these salts are dissolved in glycerol and added to the curing agent.

[0013] Furthermore, in U.S. Patent No. 4101459, for example, other authors suggest the use of aromatic, heterocyclic, or alicyclic polyamines as curing agents and salts of trifluoromethanesulfonic acid as catalysts.

[0014] More recently, a rapidly curing epoxy resin prepared by the reaction of diglycidyl ether of bisphenol A with isophoronediamine (IPD) and N-(3-aminopropyl)-imidazole (API) has also been reported, as disclosed in J.Appl.Polym.Sci.,2019,136,47950.

[0015] While some of the catalysts mentioned above can accelerate the curing rate, in many cases, mechanical properties such as peel strength and tensile strength are negatively affected. As previously stated, using them also hinders the acquisition of desirable low-emission product ratings under EMICODE certification, which is becoming a new standard in the construction market.

[0016] These facts highlight the need to consider other factors, such as toxicity, solubility, processing effectiveness, end-performance, regulatory considerations, cost, and ease of use, before selecting or developing a specific accelerator suited to or designed for a particular application.

[0017] While currently used two-component epoxy adhesives offer high mechanical properties, good adhesion to a wide range of substrates, and good durability in contact with concrete, they also exhibit some limitations, such as a limited curing rate at low temperatures. However, even though it is theoretically possible to increase the rate of the curing reaction using heat, either externally or internally, uniformly applying heat across a thick adhesive layer is often difficult, or even impossible, especially on construction sites.

[0018] In addition, most fast-curing epoxy adhesives have a short pot life, making them increasingly difficult to use on large construction sites.

[0019] It would be desirable to be able to be easily used with substantially any commercially available two-component epoxy resin composition, and by simply mixing it with the epoxy resin composition, an accelerator can be obtained that can accelerate their curing even at a low temperature of, for example, 2°C.

Summary of the Invention

Problems to be Solved by the Invention

[0020] Therefore, by mixing the accelerator, it is necessary to accelerate the curing of the two-component epoxy resin composition and minimize or eliminate any adverse effects that may have on health and the environment while rapidly developing mechanical properties, in a simple, low-cost, and environmentally friendly accelerator. In addition, the accelerator should be odorless and should not require either specific EHS labeling or ADR certification for transportation, and should not adversely affect the properties of the accelerated two-component epoxy resin composition.

Means for Solving the Problems

[0021] Therefore, an object of the present invention is to provide a simple, low-cost, and environmentally friendly accelerator composition that accelerates the curing of the two-component epoxy resin composition by mixing the accelerator as an additional component to the general two-component epoxy resin composition, rapidly develops mechanical properties even at low temperatures, and does not cause significant adverse effects on health and the environment. In addition, the accelerator should have storage stability, be easy to handle, be easily prepared from readily available raw materials, and should not adversely affect the properties of the accelerated two-component epoxy resin composition.

[0022] Surprisingly, it has been found that this object can be achieved by using an aqueous (water-based) solution of a metal salt as an additional third component to be mixed into the two-component epoxy resin composition, thereby creating a multi-component epoxy resin composition as defined in claim 1. This not only results in a significantly accelerated curing and an earlier manifestation of the mechanical properties of the epoxy resin composition, but also, in at least a preferred embodiment, improves the mechanical properties of the two-component epoxy resin composition, particularly the compressive strength and flexural strength, which was not expected. Furthermore, in order to achieve these effects, the fact that this third component only needs to be mixed in a very small amount (for example, less than 3% by weight based on its curing agent component) means that, for example, the risk of changing the properties of the two-component epoxy resin composition by imparting an undesirable plasticizing effect is extremely low. Therefore, it is possible to add it to substantially any amine-cured two-component epoxy resin composition without the need to review or improve the components of the epoxy resin composition.

[0023] In a first aspect, the present invention relates to a multi-component epoxy resin composition comprising: - a first component K1 comprising: - at least one epoxy resin A containing on average two or more epoxy groups per molecule; - optionally, at least one reactive diluent having one epoxy group per molecule; - optionally, further additives, and - a second component K2 comprising: - at least one amine curing agent B for the epoxy resin; - optionally, further additives, and - a third component K3 consisting of: - An aqueous solution of at least one metal salt M (wherein the solution contains between 20 and 80 parts by weight, preferably between 30 and 70 parts by weight, and particularly between 40 and 60 parts by weight, based on 100 parts by weight of water in the aqueous solution); Here, the weight ratio of component K2 to component K3 is between 100:0.3 and 100:10, preferably between 100:1 and 100:5.

[0024] Compared to existing solutions using current technologies, the main advantages achieved using this multi-component epoxy resin composition are as follows:

[0025] The third (accelerator) component of the present invention is odorless and non-toxic, does not require any special EHS labeling or ADR, and is therefore suitable even for DIY applications. Aside from its beneficial EHS properties, the accelerator component is extremely simple, inexpensive to prepare, based on readily available raw materials, and has storage stability even when exposed to various ambient conditions as well as air, sunlight, heat, and humidity.

[0026] This acceleration effect can be achieved even at low temperatures of 2°C, eliminating the need for heating.

[0027] The final mechanical properties and adhesive performance of the cured accelerated epoxy resin composition are not significantly adversely affected by the addition of a third component as defined in claim 1. Furthermore, in at least preferred embodiments, the accelerator component even surprisingly improves some of the important mechanical properties of the cured accelerated two-component epoxy resin composition, including its compressive and flexural strengths.

[0028] Furthermore, because even at temperatures as low as 2°C, the curing of two-component epoxy resin compositions is accelerated, the addition of a third accelerator component makes it possible to use two-component epoxy resin compositions that would otherwise cure slowly in applications where heating is not possible. This eliminates or reduces the need to incorporate additional epoxy resin compositions for each specific application.

[0029] Other aspects of the present invention are the subject of additional independent claims. Particularly preferred embodiments are the subject of dependent claims. [Modes for carrying out the invention]

[0030] Throughout this specification, the prefix "poly" in terms such as "polyisocyanate," "polyol," or "polyphenol" formally refers to a molecule containing two or more of the respective functional groups.

[0031] In this invention, the term "primary diamine" refers to a diamine having two terminal primary amino groups and does not include additional secondary amino groups. The inclusion of secondary amino groups in the molecule has been found to be disadvantageous in relation to the possibility of branching in sequential reactions of the amino-terminated impact strength modifiers in this invention.

[0032] In this specification, the term “impact strength modifier” refers to an additive to an epoxy resin matrix that, even in small amounts, particularly 0.1–15% by weight, significantly increases the toughness of the cured matrix, thereby enabling it to withstand higher bending, tensile, shock, or impact stresses before cracking or fracture. Typically, impact peel strength according to ISO 11343 is used as a measure of impact strength. In this case, the fracture energy (BE) is expressed as the area below the measurement curve (25%–90% according to ISO 11343). Typically, impact peel strength according to ISO 11343 can also be used as another measure of impact strength.

[0033] The term "modulus of elasticity" refers to the modulus of elasticity measured according to DIN EN ISO 527 (within the range of elongation of 0.05 to 0.25%), unless otherwise specified.

[0034] As used herein, the term "polymer" refers, on the one hand, to a collection of chemically homogeneous macromolecules prepared by polyreactions (polymerization, polyaddition, polycondensation), however these macromolecules differ in their degree of polymerization, molecular weight, and chain length. On the other hand, the term also includes derivatives of the aforementioned generic macromolecules obtained as a result of polymerization reactions, i.e., compounds obtained, for example, by addition or substitution reactions of functional groups in predetermined macromolecules, which may be chemically homogeneous or chemically heterogeneous. Furthermore, the term also includes so-called prepolymers, which are reactive organic preadducts whose functional groups are involved in the formation of macromolecules.

[0035] In this specification, when the term “independently” is used in relation to substituents, residues, or groups, it should be interpreted that substituents, residues, or groups having the same name may coexist within the same molecule, each having a different definition.

[0036] The term "room temperature" ("RT") refers to a temperature of 23°C unless otherwise specified.

[0037] All cited industrial standards and specifications refer to the most recent editions available at the time of the initial filing of this patent application, unless otherwise specified.

[0038] In this specification, the term "weight" refers to the mass of a compound or composition measured in kilograms.

[0039] The abbreviation "ADR," officially known as "Agreement of 30 September 1957 concerning the International Carriage of Dangerous Goods by Road," refers to a 1957 United Nations treaty regulating the transboundary transport of dangerous goods.

[0040] The abbreviation "EHS" stands for "Environment, Health, and Safety."

[0041] Ingredient K1 The first component, K1, contains the following: - At least one type of epoxy resin A containing an average of two or more epoxy groups per molecule; -In some cases, a reactive diluent having at least one epoxy group per molecule; -Further additives may be needed in some cases.

[0042] The first component K1 primarily contains epoxy resin A, which comprises at least one type of epoxy resin containing an average of two or more epoxy groups per molecule.

[0043] The epoxy resin A contained in the first component K1 of the composition may be various commonly used bifunctional or polyfunctional epoxy resins used in this art. Suitable epoxy resins can be obtained, for example, by the reaction of an epoxide compound, such as epichlorohydrin, with a polyfunctional aliphatic or aromatic alcohol, i.e., a diol, triol, or polyol. One or more epoxy resins may be used.

[0044] The epoxy resin A, which contains an average of two or more epoxy groups per molecule, is preferably a liquid epoxy resin and / or a solid epoxy resin.

[0045] The term "solid epoxy resin" is very well known to those skilled in the epoxide industry and is used in contrast to "liquid epoxy resin." The glass transition temperature of solid resins is above room temperature; that is, they can be ground to a free-flowing powder at room temperature.

[0046] Suitable epoxy resins, whether liquid or solid, are specifically diglycidyl ethers, such as those of formula (I): [ka] (In the formula, R 4 (These are divalent aliphatic or mononuclear aromatic compounds, or dinuclear aromatic groups.)

[0047] Examples of such diglycidyl ethers include, specifically, the following: bifunctional saturated or unsaturated, branched or unbranched, cyclic or open-chain C2-C2 compounds. 30 Alcohols, such as ethylene glycol, butanediol, hexanediol diglycidyl ether, or octanediol glycidyl ether, cyclohexanedimethanol diglycidyl ether, neopentyl glycol diglycidyl ether; Diglycidyl ethers of bifunctional, low-molecular-weight to high-molecular-weight polyether polyols, such as polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether; Diglycidyl ethers of difunctional diphenols and, in some cases, triphenols (to be understood as not only pure phenols, but also, in some cases, substituted phenols).

[0048] The types of substitutions are extremely diverse. Specifically, this should be understood as a direct substitution onto the aromatic nucleus to which the phenolic OH group is attached. In addition, phenol should be understood as referring not only to mononuclear aromatic compounds but also to multinuclear or condensed aromatic compounds or heteroaromatic compounds that have a phenolic OH group directly on their aromatic or heteroaromatic base. Suitable bisphenols and possibly triphenols include, for example, 1,4-dihydroxybenzene, 1,3-dihydroxybenzene, 1,2-dihydroxybenzene, 1,3-dihydroxytoluene, 3,5-dihydroxybenzoate, 2,2-bis(4-hydroxyphenyl)propane (=bisphenol-A), bis(4-hydroxyphenyl)methane (=bisphenol-F), bis(4-hydroxyphenyl)sulfone (=bisphenol-S), naphthresorcinol, dihydroxynaphthalene, dihydroxyanthraquinone, dihydroxy-biphenyl, 3,3-bis(p-hydroxyphenyl)phthalide, 5,5-bis(4-hydroxy -phenyl)hexahydro-4,7-methanoindan, phenolphthalein, fluorescein, 4,4'-[bis(hydroxyphenyl)-1,3-phenylenebis(1-methylethylidene)] (=bisphenol-M), 4,4'-[bis(hydroxyphenyl)-1,4-phenylenebis(1-methylethylidene)] (=bisphenol-P), 2,2'-diallyl-bisphenol-A, diphenols and dicresols prepared by reacting phenol or cresol with diisopropylidenebenzene, phloroglucin, bile acid esters, novolacs of phenol or cresol having an -OH functional value of 2.0 to 3.5, and all isomers of the above compounds.

[0049] A preferred solid epoxy resin A has formula (II): [ka]

[0050] In this formula, the substituents R' and R'' are independently H or CH3, respectively. In addition, the exponent s is greater than 1.5 and in particular has a value between 2 and 12.

[0051] Such solid epoxy resins are commercially available from companies such as Dow, Huntsman, or Hexion.

[0052] Compounds of formula (II) having an exponent s between 1 and 1.5 are known to those skilled in the art as semi-solid epoxy resins. In the present invention, they are also considered solid resins. However, preferred are epoxy resins in a narrower sense, namely those with an exponent s greater than 1.5.

[0053] A preferred liquid epoxy resin A has formula (III): [ka]

[0054] In this formula, the substituents R''' and R'''' are independently H or CH3. In addition, the exponent r has a value between 0 and 1. It is preferable that r has a value less than 0.2.

[0055] Therefore, these are preferably bisphenol A (DGEBA), bisphenol F, and diglycidyl ethers of bisphenol A / F (where "A / F" refers to a mixture of acetone and formaldehyde used as a reactant in their preparation). Such liquid resins are available, for example, as Araldite® GY250, Araldite® PY304, Araldite® GY282 (Huntsman), or DER® 331 or DER® 330 (Olin), or Epikote 828 (Hexion).

[0056] Furthermore, so-called novolac is also a suitable epoxy resin A. Specifically, they have the following formula: [ka] (In the formula, [ka] (Alternatively, it is CH2, R1 = H or methyl, and z = 0 to 7.)

[0057] Specifically, these are novolacs (R2=CH2) of phenol or cresol.

[0058] Such epoxy resins are marketed under the following trade names: EPN, or ECN, as well as the Tactix® 556 (manufactured by Huntsman), or the DEN® product line (manufactured by Dow Chemical).

[0059] It is preferable that epoxy resin A is a liquid epoxy resin of formula (III). In a more preferred embodiment, the thermosetting epoxy resin composition includes at least one liquid epoxy resin of formula (III), and furthermore, at least one solid epoxy resin of formula (II).

[0060] Particularly preferred are: bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, or bisphenol A / F diglycidyl ether, specifically Araldite® GY240, Araldite® GY250, Araldite® GY281, Araldite® GY282, Araldite® GY285, Araldite® PY304 or Araldite® PY720 (all manufactured by Huntsman), or DER® 330, DER® 331, DER® 332, DER® 336, DER® 351, DER® 352, DER® 354 or DER® 356 (all manufactured by Olin), or novolac glycidyl ether.

[0061] A preferred material is a novolac glycidyl ether derived from phenol-formaldehyde novolac, also known as epoxyphenol novolac resin.

[0062] Such novolac glycidyl ethers are commercially available from, for example, Olin, Huntsman, Momentive, or Emerald Performance Materials. Preferred types include: DEN® 431, DEN® 438, or DEN® 439 (Olin); Araldite® EPN 1179, Araldite® EPN 1180, Araldite® EPN 1182, or Araldite® EPN 1183 (Huntsman); Epon® 154, Epon® 160, or Epon® 161 (Momentive); or Epalloy® 8250, Epalloy® 8330, or Epalloy® 8350 (Emerald Performance Materials).

[0063] The ratio of epoxy resin A is preferably 10 to 50% by weight, particularly 15 to 40% by weight, and more preferably 20 to 30% by weight, based on the weight of component K1.

[0064] In addition, the composition may optionally contain at least one reactive diluent having one epoxy group per molecule in component K1. Small diglycidyl ethers are also possible as additional reactive diluents.

[0065] These reactive diluents are specifically the following: - Monofunctional, saturated or unsaturated, branched or unbranched, cyclic or open-chain C4-C 30 Glycidyl ethers of alcohols, specifically selected from the group consisting of butanol glycidyl ether, hexanol glycidyl ether, 2-ethylhexanol glycidyl ether, allyl glycidyl ether, tetrahydrofurfuryl and furfuryl glycidyl ether, and trimethoxysilyl glycidyl ether; - Difunctional, saturated or unsaturated, branched or unbranched, cyclic or open-chain C2-C 30 Glycidyl ethers of alcohols, specifically selected from the group consisting of glycidyl ethers of ethylene glycol, butanediol, hexanediol, or octanediol, cyclohexanedimethanol diglycidyl ether, and neopentyl glycol diglycidyl ether; - Trifunctional or polyfunctional, saturated or unsaturated, branched or unbranched, cyclic or open-chain alcohol glycidyl ethers, such as epoxidized castor oil, epoxidized trimethylolpropane, epoxidized pentaerythritol, or aliphatic polyols, such as sorbitol, glycerol, or trimethylolpropane polyglycidyl ethers; - Glycidyl ethers of phenol and aniline compounds, specifically selected from the group consisting of phenyl glycidyl ether, cresyl glycidyl ether, p-tert-butyl-phenyl glycidyl ether, nonylphenol glycidyl ether, 3-n-pentadecenyl glycidyl ether (from cashew nut shell oil), N,N-diglycidylaniline, and p-aminophenol triglycidyl; - Epoxylated amines, such as N,N-diglycidylcyclohexylamine; - Epoxy mono- or dicarboxylic acids, specifically selected from the group consisting of glycidyl neodecanoate, glycidyl methacrylate, glycidyl benzoate, diglycidyl phthalate, tetra- and hexa-hydrophthalates, diglycidyl esters of dimer fatty acids, and diglycidyl esters of terephthalic acid and trimellitic acid; - Epoxy-modified difunctional or trifunctional low-to-high molecular weight polyether polyols, specifically polyethylene glycol diglycidyl ether or polypropylene glycol diglycidyl ether.

[0066] Particularly preferred are: hexanediol diglycidyl ether, cresyl glycidyl ether, p-tert-butylphenyl glycidyl ether, polypropylene glycol diglycidyl ether, and polyethylene glycol diglycidyl ether.

[0067] It is advantageous that the total ratio of the reactive diluent is 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the weight of component K1.

[0068] The weight ratio of epoxy resin A to epoxy group-containing reactive diluent in component K1 is preferably in the range of 60 / 40 to 95 / 5, and more particularly in the range of 70 / 30 to 95 / 10.

[0069] The epoxy resin A in component K1 and, optionally, the epoxy-functional compound in the reactive diluent are preferably selected from the following: liquid bisphenol A diglycidyl ether, liquid bisphenol F diglycidyl ether, C12 / C14-alkyl monoglycidyl ether, diglycidyl ether of 1,6-hexanediol, diglycidyl ether of 1,4-butanediol, and combinations thereof.

[0070] In addition to these components, component K1 may, in some cases, contain further additives, which will be explained below.

[0071] Component K2 The second component, K2, contains the following: - At least one amine curing agent B for epoxy resins; - Additional additives may be needed in some cases.

[0072] The second component, K2, firstly contains at least one type of amine curing agent B for epoxy resins.

[0073] This curing agent is preferably included in an amount between 4 and 50% by weight, more preferably between 5 and 40% by weight, and particularly between 7 and 25% by weight, based on the total weight of component K2.

[0074] The curing agent B is preferably a single compound selected from the group consisting of poly(ethyleneimine), polyamidoamine, amino-terminated butadiene / acrylonitrile copolymer, and polyamine, or a mixture of several compounds.

[0075] Examples of suitable curing agents B include, for example, the following: • Primary diamines of aliphatic, alicyclic, or aromatic aliphatic groups: For example, ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 2-methyl-1,2-propanediamine, 2,2-dimethyl-1,3-propanediamine, 1,3-butanediamine, 1,4-butanediamine, 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- and 2,4,4-trimethylhexamethylenediamine (TMD), 1,7-Heptanediamine, 1,8-Octanediamine, 1,9-Nonanediamine, 1,10-Decanediamine, 1,11-Ecanediamine, 1,12-Dodecanediamine, 1,2-, 1,3- and 1,4-Diaminocyclohexane, Bis-(4-Aminocyclohexyl)methane (H 12 -MDA), 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 (M-MECA), 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (=isophoronediamine i.e., IPDA), 2- and 4-methyl-1,3-diaminocyclohexane and mixtures thereof, 1,3- and 1,4-bis-(aminomethyl)cyclohexane, 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, and 1,3- and 1,4-xylylenediamine; • Aliphatic primary diamines containing ether groups: For example, 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, and higher oligomers of these diamines, bis-(3-aminopropyl)polytetrahydrofuran, and other polytetrahydrofrangamines having molecular weights in the range of 350 to 2000, as well as polyoxyalkylenediamines. Typically, the latter are reaction products of amination of polyoxyalkylenediols and are available, for example, under the names Jeffamine® (Huntsman), Polyetheramin (BASF), or PC Amine® (Nitroil). Particularly preferred polyoxyalkylenediamines are: Jeffamine® D-230, Jeffamine® D-400, Jeffamine® D-2000, Jeffamine® XTJ-511, Jeffamine® ED-600, Jeffamine® ED-900, Jeffamine® ED-2003, Jeffamine® XTJ-568, Jeffamine® XTJ-569, Jeffamine® XTJ-523, Jeffamine® XTJ-536, Jeffamine® XTJ-542, Jeffamine® XTJ-559, Jeffamine® EDR-104, Jeffamine® EDR-148, Jeffamine® EDR-176; Polyetheramin D230, Polyetheramin D400, and Polyetheramin D2000, PC Amine® DA250, PC Amine® DA400, PC Amine® DA650, and PC Amine® DA2000; • Polyamines having secondary amino groups: For example, diethylenetriamine (DETA), dipropylenetriamine (DPTA), bishexamethylenetriamine (BHMT), 3-(2-aminoethyl)aminopropylamine, N3-(3-aminopentyl)-1,3-pentanediamine, N5-(3-aminopropyl)-2-methyl-1,5-pentanediamine, N5-(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine, N,N'-dibutylethylenediamine; N,N'-di-tert-butylethylenediamine, N,N'-diethyl-1,6-hexanediamine, 1-(1-methylethylamino) -3-(1-methylethylaminomethyl)-3,5,5-trimethylcyclohexane (Jefflink® 754, manufactured by Huntsman), N4-cyclohexyl-2-methyl-N2-(2-methylpropyl)-2,4-pentanediamine, N,N'-dialkyl-1,3-xylylenediamine, bis-(4-(N-alkylamino)cyclohexyl)methane, 4,4'-trimethylenedipiperidine, N-alkylated polyetheramines, e.g., Jeffamine® type SD-231, SD-401, SD-404, and SD-2001 (manufactured by Huntsman); • Amine / polyepoxide addition reaction product: Specifically, the addition reaction product of the aforementioned polyamine and diepoxide in a molar ratio of at least 2:1, particularly 2:1 to 6:1; • Polyamidoamine: Reaction products of monobasic or polybasic carboxylic acids or their esters or anhydrides, particularly dimer fatty acids, and aliphatic, alicyclic, or aromatic polyamines, especially polyalkyleneamines such as DETA or triethylenetetramine (TETA), used in stoichiometric excess, specifically the following commercially available polyamidoamines: Versamid® 100, 125, 140, and 150 (manufactured by Cognis), Aradur® 223, 250, and 848 (manufactured by Huntsman), Euretek® 3607, Euretek® 530 (manufactured by Huntsman), Beckopox® EH651, EH654, EH655, EH661, and EH663 (manufactured by Cytec); • Polyethyleneimine (PEI): These are branched, high-molecular-weight amines obtained from the polymerization of ethyleneimines. Preferred polyethyleneimines typically have an average molecular weight in the range of 250 to 25,000 g / mol and contain tertiary, secondary, and primary amino groups. Polyethyleneimines can be obtained, for example, under the trade name Lupasol® (manufactured by BASF), such as Lupasol® FG, Lupasol® G20, and Lupasol® PR8515. • Amines derived from cashew nut shells: These are reaction products of cardanol (whose main component is liquid cashew nut shell (CNSL)) and amines, and have a phenalcamin structure. They are renewable raw materials that have good properties for use as curing agent B.

[0076] Specifically, suitable polyamines for curing agent B are: polyoxyalkylenediamines having a molecular weight of less than 500 g / mol (Jeffamine® D-230, Jeffamine D400, Jeffamine® EDR-148), 4,7,10-trioxatridecane-1-13-diamine, 4,9-dioxadodecane-1,12-diamine, ethylenediamine, and / or 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.02,6]decane (TCD-Diamin®, manufactured by Celanese Chemicals). Specifically, polyethyleneimines having a molecular weight Mw of less than 100,000 g / mol, and especially less than 50,000 g / mol, have been found to be particularly suitable.

[0077] Specifically, the polyamines, preferably diamines or triamines, are selected from the group consisting of: aliphatic diamines or triamines containing ether groups, particularly polyoxyalkylene-diamines and triamines; particularly polyoxyethylene-diamines and triamines, polyoxypropylene-diamines and triamines; polyoxybutylene-diamines and triamines, amino-terminated polybutadienes and butadiene / acrylonitrile copolymers, or mixtures thereof.

[0078] Specifically, these are polyoxyalkylene polyamines having two or three amino groups, which are commercially available under trade names such as: Jeffamine® (manufactured by Huntsman Chemicals), Polyetheramin (BASF), or PC Amine® (Nitroil), and mixtures of the above-mentioned polyamines.

[0079] Furthermore, the curing agent component K2 may contain an accelerator. A suitable accelerator is a substance that accelerates the reaction between an amino group and an epoxide group, and specifically includes: acids, or compounds that become acids by hydrolysis, specifically 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, and other organic or inorganic acids, specifically phosphoric acid, or mixtures of the above-mentioned acids and esters of acids; tertiary amines such as accelerator B mentioned above, or 1,4-diazabicyclo[2.2.2]octane, triethanolamine, imidazoles such as N-methylimidazole, N-vinylimidazole or 1,2-dimethylimidazole, salts of such tertiary amines, quaternary ammonium salts, specifically benzyltrimethylammonium chloride, amidine, specifically 1,8-diazabicyclo[5.4.0]undes-7-ene, guanidine, specifically 1,1,3,3-tetramethylguanidine, phenol, specifically bisphenol, phenol resin, or Mannich base, for example specifically 2,4,6-tris(dimethylaminomethyl)phenol or 2,4,6-tris(N,N-dimethyl-4-amino-2-azabutyl)phenol, phosphate, for example specifically di- or tri-phenyl phosphate, or mercapto-containing compounds. Preferred accelerators are acids, tertiary amines, or Mannich bases.

[0080] Of these, the most preferred are salicylic acid, or 2,4,6-tris(dimethylaminomethyl)phenol or 2,4,6-tris(N,N-dimethyl-4-amino-2-azabutyl)phenol, or a combination thereof.

[0081] More preferably as accelerators are certain compounds containing at least one dimethylamino group, particularly benzyldimethylamine, α-methylbenzyldimethylamine, N,N-diethyl-N',N'-dimethyl-1,3-propanediamine, N,N-dimethylethanolamine, 3-(N,N-dimethylamino)propane-1-ol, 2- or 4-(dimethylaminomethyl)phenol, 2,4- or 2,6-bis(N,N-dimethylaminomethyl)phenol, 2,4,6-tris(N,N-dimethylaminomethyl)phenol, 2,4,6-tris(N,N-dimethyl-4-amino-2-azabutyl)phenol, or specifically, N,N,N',N'-tetramethyl-1,2-ethanediamine, N,N,N',N'-tetramethyl-1,3-propanediamine, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N,N',N'-tetramethyl Tramethyl-1,6-hexanediamine, N,N,N',N',N''-pentamethyldiethylenetriamine, N,N,N',N',N''-pentamethyldipropylenetriamine, N,N,N',N',N''-pentamethyl-N-(2-aminoethyl)-1,3-propanediamine, N,N-dimethyl-1,2-ethanediamine, N,N-dimethyl-1,3-propanediamine, N,N-dimethyl-1,4-butanediamine, N,N-dimethyl These are thyl-1,6-hexanediamine, 2-(2-(dimethylamino)ethylamino)ethylamine, 2-(3-(dimethylamino)propylaminoethylamine, 3-(2-(dimethylamino)ethylamino)propylamine, 3-(3-(dimethylaminopropylamino)propylamine (DMAPAPA), bis(2-(N,N-dimethylamino)ethyl)amine, or bis(3-(N,N-dimethylamino)propyl)amine.

[0082] Particularly preferred are N,N,N',N',N''-pentamethyldiethylenetriamine, 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA), or bis(3-(N,N-dimethylamino)propyl)amine. These accelerators are readily available, have low odor, enable high compressive strength and high adhesion, and have virtually no problems with curing at cold temperatures. The most preferred accelerator is 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA). DMAPAPA has low odor, is toxically safe, and is commercially available.

[0083] Furthermore, the composition may contain at least one impact strength modifier I in either or both of components K1 and K2.

[0084] Impact strength modifier I has the advantage of increasing the toughness of the epoxy resin composition, for example.

[0085] The composition preferably contains at least one impact strength modifier I in either or both of components K1 and K2, in an amount between 3 and 25% by weight, preferably between 4 and 20% by weight, and particularly between 5 and 15% by weight, based on the total weight of components K1 and K2. This amount refers to a purely active impact strength modifier and does not include solvents or other solid or liquid additives commonly used for storage, handling, dispersion, dilution improvement, or other purposes.

[0086] Suitable impact strength modifiers I include, for example, core-shell polymers. Core-shell polymers consist of an elastic core polymer and a rigid shell polymer. Particularly suitable core-shell polymers consist of a core of an elastic acrylate or butadiene polymer surrounded by a rigid shell of a rigid thermoplastic polymer. This core-shell structure is formed either by simultaneously demixing block copolymers or by grafting after pre-setting by polymerization or suspension polymerization as latex.

[0087] Preferred core-shell polymers are so-called MBS polymers, which are commercially available under the trade names Clearstrength® by Arkema, Paraloid® by Dow (formerly Rohm and Haas), or F-351® by Zeon. Particularly preferred are core-shell polymer particles that already exist as dried polymer latex. Examples include: GENIOPERL® M23A (polysiloxane core and acrylate shell) by Wacker, NEP series radiation-crosslinked rubber particles by Eliokem, or Nanoprene® by Lanxess, or Paraloid® EXL by Dow. Other equivalent examples of core-shell polymers are available from Evonik Hanse GmbH, Germany under the name Albidur®. Nanoscale silicates in epoxy matrices are also preferred, for example, available from Evonik Hanse GmbH, Germany under the trade name Nonopox.

[0088] More suitable as impact strength modifier I are liquid rubbers which are carboxyl or epoxide-terminated acrylonitrile / butadiene copolymers or derivatives thereof. Such liquid rubbers are commercially available, for example, from Emerald Performance Materials LLC under the names Hypro® (formerly Hycar®) CTBN, CTBNX, and ETBN. Particularly suitable derivatives which are epoxy-containing elastomer-modified prepolymers include, for example, the Polydis® product line from Struktol GmbH (Schill+Seilacher Group, Germany), preferably the Polydis® 36 product line, or the Albipox® product line (Evonik Hanse GmbH, Germany). In another embodiment, the impact strength modifier is a polyacrylate liquid rubber which is fully miscible with liquid epoxy resin and separates into microdroplets only when the epoxy resin matrix has cured. Such polyacrylate liquid rubber is available, for example, from Dow (formerly Rohm and Haas) under the designation 20208-XPA.

[0089] As will be obvious to those skilled in the art, it is also possible to use mixtures of multiple liquid rubbers, in particular mixtures of carboxyl-terminated or epoxide-terminated acrylonitrile / butadiene copolymers or derivatives thereof, and epoxy-terminated or otherwise functionalized polyurethane prepolymers.

[0090] A suitable impact strength modifier I is the reaction product of carboxylated solid nitrile rubber and excess epoxy resin.

[0091] Furthermore, a polymer of formula (IV) containing an epoxide group is preferred as the impact strength modifier I. [ka]

[0092] Here, R 7 is a carboxyl-terminated butadiene / acrylonitrile copolymer (CTBN), which is a divalent group after removing the terminal carboxyl group. The group R 4 is as defined and described by formula (I) above.

[0093] Such an epoxy-functional impact modifier should be present only in component K1.

[0094] Also preferably suitable as impact strength regulator I is a polymer of formula (V).

Chemical formula

[0095] In this formula, n and n' are each independently a numerical value from 0 to 7, preferably 0 or 1 or 2, provided that n + n' is a numerical value from 1 to 8, particularly 1 or 2.

[0096] Furthermore, R 1 is a linear or branched polyurethane prepolymer end-capped with n + n' isocyanate groups, with all terminal isocyanate groups removed. R 2 and R 3 are each independently an aliphatic, alicyclic, aromatic, or araliphatic group having 1 to 20 C atoms and optionally heteroatoms selected from O, N, and S, particularly O and N.

[0097] If its substituents R 2 and R 3 have reactivity with the epoxy group, the impact strength regulator I of formula (V) is part of component K2. Its substituents R 2 and R 3However, if it is reactive with an amino group, then impact strength modifier I of formula (V) is part of the curing agent component K1. Such non-reactive impact strength modifiers, or those that can coexist with either components K1 or K2, may be incorporated into either or both of components K1 or K2. This principle applies not only to those of formula (V) but to all impact strength modifiers.

[0098] In a preferred embodiment of the impact strength modifier according to formula (V), R 1 However, it is a linear polyurethane prepolymer containing at least n+n' terminal isocyanate groups, after which the n+n' terminal isocyanate groups have been removed.

[0099] R 2 and R 3 This is a residue of cardanol after the H atom of hydroxyl has been removed, and it is bonded via an oxygen atom.

[0100] Cardanol (CAS Registry Number: 37330-39-5) is a phenolic lipid obtained from anacardic acid, and is the main component of cashew nut shell liquid (CNSL), a by-product of cashew nut processing. The name of the substance is derived from an abbreviation of the genus Anacardium, which includes the cashew nut tree and Anacardium occidentale. Aside from being a particularly effective impact strength modifier, impact modifier I, which is end-capped with cardanol, has the advantage of being inexpensive and partially based on natural, renewable resources.

[0101] Cardanol is sold commercially, for example, by Cardolite Corporation under the trade name Cardolite® NC-700.

[0102] As impact strength modifier I, block copolymers, particularly solid block copolymers, are also preferred. These block copolymers can be obtained by anionic polymerization or controlled radical polymerization of a methacrylate ester and at least one further monomer having an olefinic double bond. Preferred monomers having an olefinic double bond are those in which the double bond is directly conjugated to a heteroatom or at least one further double bond. Specifically, monomers selected from the group including styrene, butadiene, acrylonitrile, and vinyl acetate are suitable. Preferred acrylate-styrene-acrylic acid (ASA) copolymers are, for example, commercially available from GE Plastics under the name GELOY® 1020. Particularly preferred block copolymers are methyl methacrylate, styrene, and butadiene block copolymers. Such block copolymers are, for example, commercially available from Arkema under the group name SBM triblock copolymer.

[0103] A further suitable impact strength modifier I is an amino-terminated acrylonitrile / butadiene copolymer, which is part of the curing agent component K2.

[0104] A more suitable impact strength modifier I is an epoxy-terminated polyurethane polymer, in which the first prepolymer is prepared from di- / tri-isocyanates, polymer polyols, and alkoxylated bisphenols, and then reacted with an epoxy compound containing primary or secondary hydroxyl groups. These are described in European Patent Application Publication No. 1972646A1.

[0105] Further preferred impact strength modifiers I are described in European Patent Application Publication No. 2917254A1 and European Patent Application Publication No. 2917255A1.

[0106] Preferably, the weight ratio of all epoxy-functional compounds in the composition (e.g., epoxy resin A, reactive diluent) to the pure impact strength modifier I (excluding solvents, additives, etc.) in the composition is between 1 and 3 (w / w), preferably between 1.2 and 2.9 (w / w), and more preferably between 1.3 and 2.7 (w / w). This ratio allows for particularly efficient strengthening of the composition, thereby enabling the use of a wide range of impact strength modifiers I to achieve beneficial mechanical properties. It is worth noting that in this calculation, epoxy-functional impact strength modifiers are always considered as impact strength modifier I, and not as epoxy-functional compounds. Naturally, other functionalized (e.g., amino group-containing) impact strength modifiers are always considered as impact strength modifier I in the weight ratio calculation.

[0107] Furthermore, it is preferable that the composition contains at least one filler F in either or both of components K1 and K2.

[0108] The composition preferably contains at least one filler F in either or both of components K1 and K2, in an amount between 15 and 80% by weight, preferably between 17 and 70% by weight, and particularly between 20 and 60% by weight, based on the total weight of the combination of components K1 and K2.

[0109] The use of fillers is advantageous because they improve the aging resistance of the adhesive and have a favorable effect on its mechanical properties.

[0110] Suitable fillers F include, for example, the following inorganic and organic fillers: possibly coated with fatty acids, especially stearic acid esters, ground or precipitated calcium carbonate, barium sulfate (barite), talc, quartz powder, silica sand, dolomite, wollastonite, kaolin, mica (potassium aluminum silicate), molecular sieves, alumina, aluminum hydroxide, silica (by pyrolysis or precipitation), cristobalite, cement, gypsum, flue ash, carbon black, graphite, metal powders such as aluminum, copper, iron, silver, or steel, PVC powder or hollow spheres such as solid or hollow glass spheres, and organic hollow spheres.

[0111] More preferable as filler F are layered inorganic materials, particularly layered inorganic materials that have been ion-exchanged using organic ions. The ion-exchanged layered mineral material may be either cation-exchanged or anion-exchanged layered mineral material. It is also possible that the adhesive contains both cation-exchanged and anion-exchanged layered mineral materials simultaneously. Such layered inorganic materials may also have the additional advantage of functioning as corrosion inhibitors. In this case, if the inorganic materials have a significant corrosion-resistant effect, they should be attributed to corrosion inhibitors (as further described below) in the sense of the present invention.

[0112] Therefore, cation-exchanged layered minerals are obtained from layered minerals in which at least a portion of the cations are replaced by organic cations. Examples of such cation-exchanged layered minerals are specifically described in U.S. Patent No. 5,707,439 or U.S. Patent No. 6,197,849, which also describe processes for preparing these cation-exchanged layered minerals. Preferred layered minerals are layered silicates. Particularly preferred are phyllosilicates, especially bentonite, as described in columns 2, line 38 to 3, line 5 of U.S. Patent No. 6,198,849. Layered minerals such as kaolin, montmorillonite, hectorite, or illite have been found to be particularly preferred.

[0113] Preferred cation-exchanged layered inorganic materials are known to those skilled in the art as organoclay or nanoclay, and are commercially available under the following group names, for example: Tixogel® (Byk Additives & Instruments) or Nanofil® (Byk Additives & Instruments), Cloisite®, or Nanomer® (Nanocor Inc.), or Garamite® (Byk Additives & Instruments).

[0114] Anion-exchanged layered minerals can be obtained from layered minerals in which at least some of the anions have been replaced with organic anions. An example of anion-exchanged layered mineral is hydrotalcite in which at least some of the carbonate anions in the intermediate layer have been replaced with organic anions.

[0115] It is preferable that the filler F contains particles having an average particle size of at least 0.1 to 1 mm, preferably at least 0.2 to 2 mm, and particularly at least 0.5 to 5 mm.

[0116] This provides additional advantages, such as the large filler particles ensuring a sufficiently thick adhesive layer, and the reinforcing element S acting as a spacer to prevent the adhesive from being squeezed out when the applied adhesive is compressed.

[0117] The average particle size of filler F is generally measured by, for example, dynamic light scattering, or preferably by sieve analysis according to ASTM C136-06.

[0118] Furthermore, the multi-component epoxy resin composition may contain additional additives in either or both of components K1 and K2. Examples of such additives include: - Solvents, film-forming aids, or extenders, such as toluene, xylene, methyl ethyl ketone, 2-ethoxyethanol, 2-ethoxyethyl acetate, benzyl alcohol, ethylene glycol, diethylene glycol butyl ether, dipropylene glycol butyl ether, ethylene glycol butyl ether, ethylene glycol phenyl ether, N-methylpyrrolidone, propylene glycol butyl ether, propylene glycol phenyl ether, diphenylmethane, diisopropylnaphthalene, mineral oil fractions, such as Solvesso type (manufactured by Exxon), aromatic hydrocarbon resins, especially phenol group-containing types, sebacate esters, phthalate esters, organophosphate esters and sulfate esters, and sulfonamides; - Corrosion inhibitors (also called corrosion inhibitors), particularly layered inorganic materials such as fluorphlogopite and pulverized muscovite, and modified hydrotalcite (MHT) (also called "layered double hydroxide" (LHD)), organic corrosion inhibitors such as amines, urea, mercaptobenzothiazole (MBT), benzotriazole and toluenetriazole, aldehydes, heterocyclic nitrogen compounds, sulfur-containing compounds and acetylene compounds, and furthermore ascorbic acid, succinic acid, tryptamine, caffeine and extracts from natural raw materials; - Reactive diluents, such as epoxy reactive diluents (as previously described), epoxidized soybean oil or linseed oil, compounds having acetacetate groups, especially acetoacetylated polyols, butyrolactones, and similarly, isocyanates, and silicones having reactive groups; - Polymers such as polyamides, polysulfides, polyvinyl formal (PVF), polyvinyl butyral (PVB), polyurethane (PUR), polymers containing carboxyl groups, polyamides, butadiene-acrylonitrile copolymers, styrene-acrylonitrile copolymers, butadiene-styrene copolymers, ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate, and alkyl (meth)acrylates, homopolymers or copolymers of unsaturated monomers from this group, particularly chlorosulfonated polyethylene, polymers containing fluorine, sulfonamide-modified melamine, and cleaning montan wax; - Fibers, for example, plastic fibers, carbon fibers, or glass fibers; - Pigments, such as titanium dioxide or iron oxide or organic pigments; - Rheological modifiers, for example, particularly thickeners, such as layered silicates, such as bentonite, derivatives of castor oil, hydrogenated castor oil, polyamides, polyurethanes, urea compounds, pyrolysis-derived silicic acid, cellulose ethers, and hydrophobically modified polyoxyethylenes; - Adhesion promoters, for example, organoalkoxysilanes, such as 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-N'[3-(trimethoxysilyl)propyl]ethylenediamine, 3-ureidopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, vinyltrimethoxysilane, or corresponding organosilanes having an ethoxy group or (poly)etheroxy group instead of a methoxy group; - Stabilizers against oxidation, heat, light, and UV rays; - Flame retardants, specifically compounds such as: alumina (Al(OH)3; also called ATH "aluminum trihydrate"), magnesium hydroxide (Mg(OH)2; also called MDH "magnesium dihydrate"), ammonium sulfate ((NH4)2SO4), boric acid (B(OH)3), zinc borate, melamine borate, and melamine cyanurate; phosphorus-containing compounds such as ammonium phosphate ((NH4)3PO4), ammonium polyphosphate, melamine phosphate, melamine pyrophosphate, triphenyl phosphate, diphenyl cresyl phosphate, tricresyl phosphate, triethyl phosphate, tris-(2-ethylhexyl) phosphate, trioctyl phosphate, mono-, bis-, and tris-(isopropylphenyl) phosphates, resorcinol bis(diphenyl phosphate), resorcinol diphosphate oligomer, tetraphenyl resorcinol diphosphate, ethylenediamine diphosphate, and bisphenol A bis(diphenyl phosphate); halo For example, chloroalkyl phosphates, specifically tris(chloroethyl) phosphate, tris(chloropropyl) phosphate, and tris(dichloroisopropyl) phosphate; polybrominated diphenyl ethers, especially decabromodiphenyl ether; polybrominated diphenyl oxide; tris[3-bromo-2,2-bis(bromomethyl)propyl] phosphate; tetrabromobisphenol A; bis(2,3-dibromopropyl) ether of bisphenol A; brominated epoxy Cyanopolymers, ethylene-bis(tetrabromophthalimide), ethylenebis(dibromonolbornanedicarboxymide), 1,2-bis-(tribromophenoxy)ethane, tris(2,3-dibromopropyl)isocyanurate, tribromophenol, hexabromocyclodecane, bis(hexachlorocyclopentadienone)cyclooctane, and chloroparaffins; furthermore, combinations of halogen-containing compounds with antimony trioxide (Sb2O3) or antimony pentoxide (Sb2O5); - Surfactants, for example, wetting agents, flow regulators, defoaming agents, or antifoaming agents; - Biocides, such as algaecides, fungicides, or substances that inhibit the growth of fungi.

[0119] It is clear and known to those skilled in the art which additives can be added to resin component K1 and which can be added to curing agent component K2. In particular, it must be ensured that such additives do not impair storage stability at all or only slightly. Therefore, it is clear to those skilled in the art that the polyamine reacts with the epoxide in resin component K1 and, as a result, is contained only in curing agent component K2.

[0120] In a preferred embodiment, the multi-component epoxy resin composition contains in either or both of components K1 and K2 an additive selected from the list of adhesion promoters, wetting agents, and degassing agents, in an amount between 0.1 and 5% by weight, preferably between 0.25 and 4% by weight, and particularly between 0.5 and 3% by weight, based on the combination of components K1 and K2.

[0121] In the epoxy resin composition, the ratio of the number of amine groups that react with the epoxide groups to the number of epoxide groups is preferably in the range of 0.7 to 1.5, and more particularly in the range of 0.8 to 1.2.

[0122] In the epoxy resin composition, the weight ratio of epoxy resin A, curing agent B, impact resistance modifier I, and filler F is preferably in the range of A:B:I:F = 1:(0.25~1):(0.25~1):(1~4), and more particularly in the range of = 1:(0.3~0.5):(0.3~0.5):(1.5~3.5).

[0123] Component K3 The third component K3 of the multi-component epoxy resin composition consists of an aqueous solution of at least one metal salt M, wherein the solution contains between 20 and 80 parts by weight, preferably between 30 and 70 parts by weight, and particularly between 40 and 60 parts by weight, based on 100 parts by weight of water in the aqueous solution.

[0124] Furthermore, the weight ratio of component K2 to component K3 is, in all embodiments, between 100:0.3 and 100:10, particularly between 100:0.5 and 100:7.5, preferably between 100:1 and 100:5, and most preferably between 100:1.5 and 100:3.

[0125] In this invention, the metal salt M plays a crucial role. However, its effect is only realized when the salt is completely dissolved in water within the previously specified amount range. Surprisingly, it has been found that an aqueous solution of the metal salt M produces a synergistic effect, far exceeding the effects of using the solid salt M and water individually. While undissolved metal salt M can accelerate the curing of epoxy resin compositions, and pure water can produce a similar effect, the effect found in the aqueous solution as defined above has an unexpectedly high acceleration effect and also brings about a remarkable improvement in the mechanical properties of the epoxy resin composition cured with it.

[0126] Suitable metal salts M are, in principle, all water-soluble salts based on metal cations and inorganic or organic anions.

[0127] For example, preferred are salts of Na, Ca, Mg, K, Be, Sr, Ba, La, and transition metals, insofar as they can form stable solutions in water within the scope of the claims.

[0128] Preferably, it is a magnesium salt or a calcium salt, preferably a calcium salt.

[0129] Ca is the most preferred because, when used as a metal cation, calcium is particularly active as an accelerator, improves the mechanical properties of the composition, is non-toxic, readily available, and inexpensive.

[0130] Preferred anions for the metal salt M include chlorate and nitrate anions. The most preferred is the nitrate. Nitrates provide a particularly accelerating component K3 and, unexpectedly, allow for improved mechanical properties of the cured epoxy resin composition. Furthermore, nitrates are less toxic, readily available, and inexpensive.

[0131] Therefore, the most preferred metal salt M is Ca(NO3)2.

[0132] It is also possible to use a mixture of different metal salts M within component K3.

[0133] Component K3 contains the metal salt M in an amount between 20 and 80 parts by weight, preferably between 30 and 70 parts by weight, and particularly between 40 and 60 parts by weight, based on 100 parts by weight of water in the aqueous solution. It is most preferable to use a solution of about 50 parts by weight of the metal salt M dissolved in 100 parts by weight of water. Using this concentration provides an optimal accelerating effect and can be mixed into components K1 and K2 in a sufficiently low amount without adversely affecting the curing and mechanical properties of the epoxy resin composition.

[0134] Component K3 can be easily prepared by dissolving the metal salt M in water. Distilled water or osmotically purified water is preferred, but tap water can also be used if it is not heavily contaminated with substances that may interfere with the epoxy resin composition.

[0135] One advantage of the present invention is that component K3 can be prepared on-site. This means that only the solid metal salt M needs to be transported and stored, while component K3 can be easily prepared by dissolving the desired amount of salt in readily available water. This results in the advantage of reducing the required transportation costs and storage needs.

[0136] Component K3 of the present invention can be used with substantially any available two-component amine-curing epoxy resin composition, and when using a slow-curing epoxy resin composition, higher accelerating activity can be obtained by increasing the concentration of the metal salt M.

[0137] Aside from water and metal salt M, component K3 may contain further additives. Such additives include: colorants, solution stabilizers, surfactants, biocides, stabilizers, and other additives that do not interfere with the homogeneity of the aqueous solution of component K3 or adversely affect the epoxy resin composition.

[0138] Components K1, K2, and K3 of the epoxy resin composition should be stored in separate containers and mixed only immediately before or during application. Suitable containers for storing resin K1 or curing agent K2 components include barrels, hobs, bags, buckets, cans, cartridges, or tubes. Component K3 may be stored in various watertight containers, such as glass jars, bags, buckets, or other suitable containers. These components are recyclable, meaning they can be stored for several months to over a year before use without any changes to their properties that would impair their usability. When applying epoxy resin adhesive, the resin, curing agent components K1 and K2, and accelerator component K3 should be mixed together immediately before or during application.

[0139] The mixing of these components is carried out by appropriate methods and means. The mixing may be continuous or batch. If the mixing is carried out before application, care must be taken not to allow too much time between the mixing of the components and application, because doing so may cause problems such as slow adhesion or incomplete adhesion. Specifically, the mixing is carried out at ambient temperature, which is typically in the range of about 0 to 40°C, preferably about 5 to 30°C.

[0140] When these components are mixed, hardening begins through a chemical reaction. In this case, the epoxide groups react with amino groups supporting amino hydrogen and other groups reactive with the epoxide groups, undergoing ring-opening to produce amino alcohol units. In particular, the dimethylamino group acts as a catalyst, causing the epoxide groups to further react with each other via anionic polymerization. The dissolved metal salt M further accelerates the hardening. As a result of these reactions, the adhesive hardens, yielding a crosslinked material. As is known to those skilled in the art, primary amino groups are "difunctional" with respect to epoxide groups, meaning they can react with two distinct epoxy groups.

[0141] Curing proceeds particularly at ambient temperature, or at temperatures down to 2°C. Under given conditions, it typically takes several hours to several days for it to be almost complete. Key influencing factors include temperature, stoichiometric ratio, and the presence of accelerators.

[0142] As a result of the curing reaction, a cured adhesive is obtained.

[0143] It is preferable to apply and cure the adhesive at ambient temperature, specifically in the range of 0 to 40°C, and particularly 5 to 30°C. This makes handling the adhesive particularly easy, which is especially advantageous outdoors, at construction sites, and in industrial buildings where heating is not required.

[0144] Another aspect of the present invention is a method for accelerating the curing of a multi-component epoxy resin composition, which includes the following steps: a) A step comprising a two-component epoxy resin composition comprising a first component K1 and a second component K2 as described above; b) A step comprising the third component K3 as described above; c) A step of mixing components K1, K2, and K3 in various orders; d) A step of applying a mixture of components K1, K2, and K3 to at least one substrate; e) A step of allowing the applied mixture to spontaneously harden at a temperature of at least 2°C.

[0145] Regarding the composition itself, all preferred embodiments of components K1, K2, and K3, as further described above, also apply to the method.

[0146] A preferred embodiment of this method is to cure the mixture in step d) at a temperature between 5°C and 30°C, preferably between 10°C and 25°C.

[0147] In the same or other preferred embodiments of this method, the at least one substrate is selected from: concrete, mortar, cement screed, fiber cement, brick, tile, natural stone, masonry, steel, copper, iron, aluminum, wood, carbon fiber cloth, polyester, PVC, epoxy resin, glass, and painted surfaces.

[0148] The surface of the substrate may be surface-treated before applying the adhesive, if necessary. Such pretreatments include, specifically, physical and / or chemical cleaning processes, such as polishing, sandblasting, shot peening, brushing and / or blow-off, as well as treatment with cleaning agents or solvents, or application of adhesion promoters, primer solutions or primers.

[0149] In another preferred embodiment, the substrate is part of a vehicle, specifically a road vehicle, aircraft, or ship. Preferably, the vehicle is a bus, truck, train, tram, aircraft, helicopter, ship, boat, or submarine. Most preferred vehicles are large road vehicles, especially buses, or aircraft.

[0150] Another aspect of the present invention is the use of the multi-component epoxy resin composition described above, particularly as an adhesive, sealant, or coating for the construction or renovation of buildings or for civil engineering structures.

[0151] Regarding the composition itself, all preferred embodiments of components K1, K2, and K3 of the multi-component composition described above also apply to this use.

[0152] Another aspect of the present invention is the use of an aqueous solution of at least one metal salt M as a curing accelerator for a two-component epoxy resin composition, wherein the solution contains the metal salt M in an amount between 20 and 80 parts by weight, preferably between 30 and 70 parts by weight, and particularly between 40 and 60 parts by weight, based on 100 parts by weight of water in the aqueous solution.

[0153] The two components of the aforementioned two-component epoxy resin composition refer to the epoxy resin component and the curing agent component. Further components, such as a hydraulic binder component, can also be used in the same manner.

[0154] All commercially available two-component amine-curing epoxy resin compositions are suitable for this application. Such compositions are commercially available, for example, from Sika under the trade name Sikadur®. Examples include Sikadur®-31+, Sikadur®-32+, and Sikadur®-42+VLE Hot Climate (all available from Sika).

[0155] For this application, it is preferable to use a two-component epoxy resin composition consisting of components K1 and K2 as described above. For this application, it is also preferable to use an aqueous solution of at least one metal salt M corresponding to component K3 as described above. As for the multi-component composition itself, all preferred embodiments of components K1, K2, and K3 described above also apply to this use.

[0156] In a preferred embodiment of the use of an aqueous solution of at least one metal salt M as a curing accelerator for a two-component epoxy resin composition, the metal salt M is a calcium salt.

[0157] In the same or further preferred embodiment of an aqueous solution of at least one metal salt M as a curing accelerator for a two-component epoxy resin composition, the metal salt M is a nitrate or chlorate, preferably a nitrate. [Examples]

[0158] The embodiments described below further illustrate the present invention, but do not limit it in any way, and merely illustrate some possible embodiments. "Standard conditions" or "standard weather conditions" ("NK") refers to a temperature of 23°C and 50% relative humidity (rh).

[0159] Test method The following testing method was adopted.

[0160] Compressive strength and flexural strength (EN-196-1) Compressive strength (CS) A rectangular prism of the test sample, measuring 40 × 40 × 160 mm, was prepared within a steel formwork. At 23°C and 50% rh, after 1 or 7 days, compressive stress was applied to these samples at a constant rate of 2.4 kN / s with a preload of 0.5 kN until the fracture point was reached or the first crack appeared. In each case, the compressive strength was measured at the point of maximum force.

[0161] Bending strength (FS) Rectangular prisms of the test samples, measuring 40 × 40 × 160 mm, were prepared within a steel formwork. After 7 days at 23°C and 50% rh, these samples were mounted on a three-point bending jig and bent at a speed of 0.5 kN / s until they reached their breaking point. In each case, the bending strength was measured at the breaking point.

[0162] Tensile strength (TS), elongation at break (EOB), and modulus of elasticity (E-Mod) (DIN EN ISO 527) These mechanical properties were measured by applying a mixed adhesive into a silicone mold under standard weather conditions, curing it to form dumbbell-shaped rods with a thickness of 10 mm, a length of 150 mm, a land length of 80 mm, and a land width of 10 mm. After a curing time of 7 days (NK), the specimens were removed from the mold. Tensile strength, elongation at break, and modulus of elasticity (0.05-0.25%) were measured at a tensile speed of 2 mm / min under standard conditions. These properties were measured according to DIN EN ISO 527.

[0163] Measurement of curing speed The curing rate was measured using one of two comparative tests: either by measuring the time it took for the curing sample to reach its exothermic peak temperature, or by measuring the time it took for the sample to reach a specific Shore A hardness.

[0164] Time to peak exothermic temperature (TEPT) In accordance with ASTM D2471-99, a 110g freshly mixed sample was used in a plastic box measuring 63mm in diameter and 65mm in height, and under normal weather conditions, the time to exothermic peak temperature (TETP) and the time to exothermic peak temperature (T) were measured. a The temperature was measured. The time it took to reach that temperature and the peak temperature were recorded. Reaching the exothermic peak temperature quickly indicates a fast curing rate. The curing temperature and other relevant conditions for each experiment were recorded.

[0165] Time to reach Shore A hardness (TSAH) Using Shore A hardness measurement according to DIN 53505, the time to reach a predetermined Shore A hardness was measured for samples with a layer thickness of 10 mm at 23°C at 10-minute intervals. The curing temperature and other relevant conditions for each experiment were recorded.

[0166] The two-component epoxy resin composition used The two-component epoxy resin compositions used are shown in Table 1.

[0167] The adhesives in Table 1 are typical commercially available two- or three-component epoxy resin compositions with different formulations, for example, in relation to fillers and specific reactive components. However, all of these adhesives in Table 1 contain a first component K1 and a second component K2. In each of these adhesives, the epoxy functional compound in epoxy resin A and possibly the reactive diluent in each component K1 is selected from the following: liquid bisphenol A diglycidyl ether, liquid bisphenol F diglycidyl ether, C12 / C14-alkyl monoglycidyl ether, diglycidyl ether of 1,6-hexanediol, diglycidyl ether of 1,4-butanediol, and combinations thereof. Furthermore, in each of these adhesives, the second component K2 contains a curing agent B, which is a single compound or a mixture of several compounds selected from the group consisting of poly(ethyleneimine), polyamidoamine, amino-terminated butadiene / acrylonitrile copolymer, and polyamine.

[0168] [Table 1]

[0169] Examples of component K3 The series of components K3 were prepared by dissolving a predetermined amount of each metal salt M in distilled water. Details of components K3-1 to K3-9 prepared in this way are shown in Table 2. The amounts in Table 2 represent the parts by weight of each metal salt added to 100 parts by weight of distilled water.

[0170] [Table 2]

[0171] For testing, a homogeneous mixture of component K3, as detailed in Table 2, was mixed with the curing agent component K2 of each of the two-component epoxy resin compositions used in each example. Then, the epoxy resin component K1 and curing agent component K2 of each commercially available epoxy resin composition were mixed according to the instructions for each commercial product. Next, in each example, the resin component K1 and curing agent component K2 (including each component K3) were processed into a homogeneous paste using a centrifugal mixer and immediately tested as described above.

[0172] The details and results of those experiments are shown in Table 3.

[0173] Tests on accelerating the curing speed Tables 3 and 4 below show the effect of the addition of component K3 on the curing rate in relation to the time to reach Shore A hardness and the time to reach the exothermic peak temperature.

[0174] [Table 3]

[0175] Table 3 shows that adding component K3 of the present invention to the curing agent component K2 results in a significant acceleration of curing over a wide concentration range. Initially, adding pure water reduces the acceleration, but this effect reverses as the concentration increases. This is also observed when excessively large amounts of aqueous accelerator are added. In Combiflex and SD-32, adding 16 parts by weight of accelerator K3-3 delays curing by more than 24 hours.

[0176] [Table 4]

[0177] Table 4 shows that the exothermic peak temperature itself is not significantly affected by the addition of component K3. However, an acceleration effect is clearly observed when component K3 is added, and this effect increases with increasing amounts. The time to reach the exothermic peak temperature is a straightforward indicator of the curing rate of the composition.

[0178] Tests on mechanical performance Tables 5a and 5b below show the effect of adding component K3 on the mechanical properties of the cured epoxy resin adhesive.

[0179] [Table 5]

[0180] [Table 6]

[0181] The results in Tables 5a and 5b show that adding a small amount of K3 to each K2 component results in a remarkable improvement in mechanical performance. Adding large amounts makes this effect less noticeable, and even reverses it.

[0182] Test on the concentration of metal salt M in component K3 Table 6 shows the effect of the concentration of the metal salt M of component K3 on the curing rate.

[0183] [Table 7]

[0184] The data presented in Table 6 shows that the acceleration effect does not depend linearly on the salt concentration. As previously mentioned, low salt concentrations clearly show an acceleration effect. However, it was found that when the metal salt M in component K3 is less than 20 parts by weight per 100 parts by weight of water, the concentration is too low to produce an acceleration effect unless an excess of component K3 is added. This could lead to undesirable effects due to the large amount of water added.

[0185] Tests on low curing temperatures Tables 7 and 8 show the effect of the addition of component K3 on the curing rate, measured in relation to the time to reach Shore A hardness, and on the mechanical properties after curing of samples cured at low temperatures.

[0186] [Table 8]

[0187] Table 7 shows that even at temperatures as low as 2°C, the addition of component K3 has a significant accelerating effect in both adhesives examined. The effect is even stronger at the lower temperature of 2°C than at 5°C.

[0188] Tests on different metal salts M in component K3 Tables 8 and 9 below show the effects of different types of metal salts M in component K3 on the curing rate and compressive strength after curing.

[0189] [Table 9]

[0190] [Table 10]

[0191] Tables 8 and 9 show that the effects of the present invention can be similarly achieved with different metal salts M.

[0192] Test on the dissolution of metal salt M in component K3 Table 10 shows the effect of the dissolution state of the metal salt M in component K3 on the hardening rate. For this study, comparative experiments were conducted using salt M in an undissolved (solid powder) state.

[0193] [Table 11]

[0194] Tables 8-10 show that various different metal salts M, when used as aqueous solutions in component K3 of the present invention, have the ability to accelerate hardening and improve mechanical properties. On the other hand, Table 10 shows that adding salts in powder form does not result in a significant acceleration of hardening. Combined with the further data above, including K3-1, this proves that a synergistic effect is brought about by the metal salt M solution as component K3 in the present invention.

[0195] Further experiments were conducted using components K3-7 and K3-8 (defined in Table 2). These components K3 failed to accelerate curing and did not improve the mechanical properties of the tested epoxy resin compositions. This indicates that nonmetallic salts, such as (NH4)H2PO4, are unsuitable in the context of the present invention.

Claims

1. A multi-component epoxy resin composition, - The first component K1, which includes the following: - Epoxy resin A containing at least one type of epoxy group, with an average of two or more epoxy groups per molecule; - In some cases, a reactive diluent having at least one epoxy group per molecule; - In some cases, further additives, and - Second component K2, which includes the following: - At least one type of amine curing agent B for epoxy resins; - In some cases, further additives, and - The third component K3 consists of the following: - An aqueous solution of at least one metal salt M, wherein the solution contains between 20 and 80 parts by weight, preferably between 30 and 70 parts by weight, and particularly between 40 and 60 parts by weight, of the water in the aqueous solution, based on 100 parts by weight of water in the aqueous solution. Includes, Here, the weight ratio of component K2 to component K3 is between 100:0.3 and 100:10, preferably between 100:1 and 100:

5. A multi-component epoxy resin composition.

2. The multi-component epoxy resin composition according to claim 1, characterized in that the metal salt M is a magnesium salt or a calcium salt, preferably a calcium salt.

3. The multi-component epoxy resin composition according to any one of claims 1 or 2, characterized in that the metal salt M is a nitrate or a chlorate, preferably a nitrate.

4. The multi-component epoxy resin composition according to any one of claims 1 to 3, characterized in that the composition contains at least one impact strength modifier I in either one or both of components K1 and K2.

5. The multi-component epoxy resin composition according to any one of claims 1 to 3, characterized in that the composition contains at least one filler F in either one or both of components K1 and K2.

6. A multi-component epoxy resin composition according to any one of claims 1 to 5, characterized in that the molar ratio of all amino groups in component K2, which is reactive with epoxide groups, to the number of epoxide groups in component K1 is in the range of 0.7 to 1.5, particularly 0.8 to 1.

2.

7. The multi-component epoxy resin composition according to any one of claims 1 to 6, characterized in that the amine in the amine curing agent B in component K2 is selected from aliphatic polyamines, aromatic polyamines, alicyclic polyamines, polyaminoamides, phenal alkamines, phenal alcamides, and mixtures thereof.

8. A multi-component epoxy resin composition according to any one of claims 1 to 7, characterized in that the epoxy resin A in component K1 and optionally the epoxy functional compound in the reactive diluent are selected from liquid bisphenol A diglycidyl ether, liquid bisphenol F diglycidyl ether, C12 / C14-alkyl monoglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, and combinations thereof.

9. A method for accelerating the curing of a multi-component epoxy resin composition, a) Providing a two-component epoxy resin composition comprising a first component K1 and a second component K2 as described in any one of claims 1 to 8; b) Providing a third component K3 according to any one of claims 1 to 8; c) A step of mixing components K1, K2, and K3 in various orders; d) A step of applying a mixture of components K1, K2, and K3 to at least one substrate; e) The step of allowing the applied mixture to spontaneously cure at a temperature of at least 2°C: Methods that include...

10. The method according to claim 9, characterized in that in step d), the mixture hardens at a temperature between 5°C and 30°C, preferably between 10°C and 25°C.

11. The method according to claim 9 or 10, characterized in that the at least one substrate is selected from concrete, mortar, cement screed, fiber cement, brick, tile, natural stone, masonry, steel, copper, iron, aluminum, wood, carbon fiber cloth, polyester, PVC, epoxy resin, glass, and painted surfaces.

12. Use of the multi-component epoxy resin composition according to any one of claims 1 to 8, particularly as an adhesive, sealant, or coating for the construction or renovation of buildings or civil engineering structures.

13. Use of an aqueous solution of at least one metal salt M as a curing accelerator for a two-component epoxy resin composition, wherein the solution contains the metal salt M in an amount between 20 to 80 parts by weight, preferably between 30 to 70 parts by weight, and particularly between 40 to 60 parts by weight, based on 100 parts by weight of water in the aqueous solution.

14. The use according to claim 13, characterized in that the metal salt M is a magnesium salt or a calcium salt, preferably a calcium salt.

15. The use according to claim 13 or 14, characterized in that the metal salt M is a nitrate or chlorate, preferably a nitrate.

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