Thermosetting epoxy resin composition suitable for precuring process without additive

Abstract

The invention relates to a thermosetting one-component epoxy resin composition comprising at least one liquid aromatic epoxy resin A1, at least one solid epoxy resin A2, at least one curing agent B for epoxy resins, at least one core-shell polymer D1 and at least one blocked polyurethane polymer D2. The weight ratio (A1 / A2) of the at least one liquid epoxy resin A1 to the at least one solid epoxy resin A2 is from 1.75 to 3.75, and wherein the weight ratio (D1 / D2) of the at least one core-shell polymer D1 to the at least one terminated polyurethane polymer D2 is from 1.2 to 4. The epoxy resin composition after pre-curing has sufficient overlap shear strength without additional metal bonding techniques. In addition, the fully cured epoxy resin composition provides good values of mechanical strength, overlap shear strength, impact peel, glass transition temperature (Tg) and fatigue resistance.

Description

Technical Field

[0001] This invention relates to the field of thermosetting one-component epoxy resin compositions, particularly for use as automotive body adhesives.

[0002] Existing technology

[0003] One important application area for thermosetting one-component epoxy resin compositions is in vehicle construction, particularly in bonding within the body structure. After the epoxy resin composition is applied, the body is heated in a cathodic electrocoating oven, resulting in the curing of the thermosetting one-component epoxy resin composition. Currently, these epoxy adhesives are only used in combination with other metal bonding techniques such as welding or riveting because the bonded parts cannot withstand mechanical stress before curing, such as during transport to the cathodic electrocoating oven.

[0004] Partial curing of the epoxy adhesive applied upstream of the cathodic electrocoating furnace, such as by induction heating, would be a fast and inexpensive alternative to the expensive and inconvenient thermal and mechanical metal bonding techniques already mentioned.

[0005] However, a drawback of this partial curing process is that only a limited amount of energy can typically be input into the epoxy adhesive, resulting in an excessively low lap shear strength value during the curing process.

[0006] In its fully cured state, the epoxy adhesive should also provide good mechanical strength, lap shear strength, impact peel strength, and glass transition temperature (Tg) values. Furthermore, over time and throughout the lifespan of the bonded components, the cured adhesive may experience fatigue due to wear and dynamic movement, potentially leading to premature failure.

[0007] Especially in cathodic electrocoating ovens at high temperatures of 180°C, the adhesion of conventional partially cured epoxy adhesives will fail without additional metal bonding techniques before they reach final curing.

[0008] WO 2022207411 describes a thermosetting epoxy resin composition containing a curing agent in the form of an aromatic dicarboxylic acid dihydrazide and a mixture of dihydrazides selected from glutaric acid dihydrazide, adipic acid dihydrazide, pimecrolic acid dihydrazide, 8,12-eicosadienoic acid-1,20-diacylhydrazide and 4-isopropyl-2,5-dioxoimidazolidine-1,3-bis(propionylhydrazide). This epoxy resin composition is particularly suitable for bonding to automotive body-in-white, wherein after induction pre-curing without additional metal bonding technology, the pre-cured adhesive is further cured in a further step at a temperature of approximately 180°C. Summary of the Invention

[0009] Therefore, one object of the present invention is to provide a thermosetting one-component epoxy resin composition that, after initial curing at room temperature and elevated temperatures such as 180°C (especially at 200-210°C for 30-60 seconds), possesses sufficient lap shear strength without the need for additional metal bonding techniques. Furthermore, the fully cured epoxy resin composition should provide good mechanical strength, lap shear strength, impact peel strength, glass transition temperature (Tg), and fatigue resistance.

[0010] This objective is surprisingly achieved by the thermosetting one-component epoxy resin composition according to claim 1. This epoxy resin composition has particularly good usability as a one-component thermosetting adhesive, especially as a thermosetting one-component body adhesive in motor vehicle structures.

[0011] Embodiments of the present invention

[0012] This invention relates to thermosetting one-component epoxy resin compositions comprising:

[0013] a) At least one liquid epoxy resin A1, having an average of more than one epoxy group per molecule, preferably in an amount of 37.5-55% by weight, more preferably 40-52.5% by weight, and most preferably 42.5-50% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0014] b) At least one solid epoxy resin A2, having an average of more than one epoxy group per molecule, preferably in an amount of 10-25% by weight, more preferably 12.5-20% by weight, and most preferably 13.5-17.5% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0015] c) At least one latent curing agent B for epoxy resin, wherein the latent curing agent B is selected from dicyandiamide, guanidine, guanidine, anhydrides of polycarboxylic acids and aminoguanidine, preferably dicyandiamide;

[0016] d) At least one core-shell polymer D1; and

[0017] e) At least one end-closed polyurethane polymer D2.

[0018] The weight ratio (A1 / A2) of at least one liquid epoxy resin A1 to at least one solid epoxy resin A2 is 1.75-3.75. The weight ratio (D1 / D2) of at least one core-shell polymer D1 to at least one end-closed polyurethane polymer D2 is 1.2-4.

[0019] In this article, the use of the term “independently” in relation to substituents, free radicals or groups should be interpreted as allowing substituents, free radicals or groups that have the same referent in the same molecule to appear simultaneously with different meanings.

[0020] The prefix "poly(poly)" in the names of substances such as "polyols", "polyisocyanates", "polyethers" or "polyamines" indicates that the corresponding substance contains more than one functional group per molecule that appears in its name.

[0021] In this article, "molecular weight" should be understood as the molar mass of a molecule (g / mol). "Average molecular weight" should be understood as the number-average molecular weight Mn of the oligomer or polymer mixture, which is usually determined by GPC using polystyrene as a standard.

[0022] "Primary hydroxyl group" refers to an OH group bonded to a carbon atom with two hydrogen atoms.

[0023] In this paper, the term "primary amine" refers to an NH2 group bonded to one organic group, while the term "secondary amine" refers to an NH group bonded to two organic groups that can also be part of a ring. Therefore, an amine having one primary amine is called a "primary amine", an amine having a secondary amine is correspondingly called a "secondary amine", and an amine having a tertiary amine is called a "tertiary amine".

[0024] In this article, "room temperature" refers to a temperature of 23°C.

[0025] The thermosetting one-component epoxy resin composition comprises a) at least one liquid epoxy resin A1 having an average of more than one epoxy group per molecule.

[0026] The preferred liquid epoxy resin A1 has formula (II).

[0027]

[0028] In this formula, the substituents R''' and R'''' are each independently H or CH3. Furthermore, the subscript r has a value of 0-1. Preferably, the value of r is less than 0.2.

[0029] Therefore, these preferred options are bisphenol A (DGEBA), bisphenol F, and diglycidyl ethers of bisphenol A / F (here, the designation "A / F" refers to a mixture of acetone and formaldehyde, which is used as a reactant in the preparation). Such liquid resins can be, for example, Araldite® GY 250, Araldite... ® PY 304, Araldite ® Available with GY 282 (Huntsman), DER™ 331, DER™ 330 (Olin), or Epikote 828 (Hexion).

[0030] Furthermore, so-called phenolic varnishes are suitable epoxy resins A1. These specifically have the following formula:

[0031] Where R2= Or CH2, R1 = H or methyl and z = 0-7.

[0032] Specifically, they are phenol or cresol varnishes (R2=CH2).

[0033] This epoxy resin can be marketed under names such as EPN, ECN, and Tactix. ® 556 is available from Huntsman, or as part of the DEN™ product line from Dow Chemical.

[0034] Bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, or bisphenol A / F diglycidyl ether are particularly preferred, especially Araldite. ® GY 240, Aralite ® GY 250, Araldite ® GY 281, Araldite ® GY 282, Araldite ® GY 285, Araldite ® PY 304 or Araldite ® PY 720 (both from Huntsman), or DER ® 330, DER ® 331, DER ® 332, DER ® 336, DER ® 351, DER ® 352, DER ® 354 or DER ® 356 (all from Olin), or phenolic varnish glycidyl ether.

[0035] The preferred material is phenolic varnish glycidyl ether derived from phenol-formaldehyde varnish, also known as epoxy phenolic varnish resin.

[0036] These phenolic varnish glycidyl ethers are commercially available, for example, from Olin, Huntsman, Momentive, or Emerald Performance Materials. The preferred type is DEN. ® 431. DEN ® 438 or DEN ® 439 (from Olin), Araldite® EPN 1179, Araldite ® EPN 1180, Araldite ® EPN 1182 or Araldite ® EPN 1183 (from Huntsman), Epon ® 154. Epon ® 160 or Epon ® 161 (from Momentive) or Epalloy ® 8250, Epalloy ® 8330 or Epalloy ® 8350 (from Emerald Performance Materials).

[0037] More preferably, the liquid epoxy resin A1 is a liquid epoxy resin of formula (II).

[0038] Preferably, the proportion of at least one liquid epoxy resin A1 is 37.5-55% by weight, more preferably 40-52.5% by weight, and most preferably 42.5-50% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0039] This is advantageous for high values ​​of fatigue resistance, mechanical properties, lap shear strength, and impact peel strength. This is evident, for example, in the comparison of E4 with E5 and E6 in Table 2.

[0040] The thermosetting one-component epoxy resin composition comprises b) at least one solid epoxy resin A2 having an average of more than one epoxy group per molecule.

[0041] Preferred solid epoxy resins have formula (I)

[0042]

[0043] The substituents R' and R'' here are independently H or CH3, and the value of the subscript s is >1.5, especially 2 to 12.

[0044] This solid epoxy resin is commercially available, for example from Dow, Huntsman, or Hexion.

[0045] Preferably, the proportion of at least one solid epoxy resin A2 is 10-25% by weight, more preferably 12.5-20% by weight, and most preferably 13.5-17.5% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0046] This is advantageous for high values ​​of fatigue resistance, mechanical properties, lap shear strength, and impact peel strength. This is evident, for example, in the comparison of E4 with E5 and E6 in Table 2.

[0047] The weight ratio (A1 / A2) of at least one liquid epoxy resin A1 to at least one solid epoxy resin A2 is 1.75-3.75.

[0048] It has been surprisingly found that ratios above 3.75 result in reduced fatigue resistance, mechanical properties, and impact peel strength at low temperatures. This is readily apparent, for example, in Table 2, in the comparison between Ref2 and E4-E6.

[0049] Preferably, the weight ratio (A1 / A2) of at least one liquid epoxy resin A1 to at least one solid epoxy resin A2 is 1.9-3.25, more preferably 2.25-3.25. This is advantageous for high values ​​of fatigue resistance, mechanical properties, lap shear strength, and impact peel strength. This is readily apparent, for example, in the comparison of E4 with E5 and E6 in Table 2.

[0050] The compositions of the present invention further contain c) at least one latent curing agent B for epoxy resins, wherein the latent curing agent B is selected from dicyandiamide, guanidine, guanidine, anhydrides of polycarboxylic acids, and aminoguanidine.

[0051] More preferably, curing agent B is selected from guanidine, especially dicyandiamide.

[0052] The amount of latent curing agent B used in epoxy resin is advantageously 0.1-30% by weight, especially 1-20% by weight, preferably 5-15% by weight, and particularly preferably 7.5-12.5% ​​by weight, based on the weight of epoxy resin A.

[0053] Preferably, in the thermosetting one-component epoxy resin composition, the ratio of the total number of epoxy groups of liquid epoxy resin A1 and solid epoxy resin A2 in molar to the ratio of curing agent B in molar ((A1+A2) / B) is 4-8, preferably 4.5-7.0, more preferably 5.0-6.0, and most preferably 5.0-5.5.

[0054] Preferably, the thermosetting epoxy resin composition further contains at least one accelerator C for the epoxy resin. Preferably, the accelerator C for the epoxy resin is selected from substituted ureas, imidazoles, imidazolines, and terminally capped amines, preferably substituted ureas, and more preferably aliphatic substituted ureas.

[0055] Preferred substituted ureas are those of formula (III).

[0056]

[0057] R1 and R2 are independently hydrogen atoms or monovalent alkyl groups having 1 to 10 carbon atoms and optionally also containing oxygen atoms, nitrogen atoms and / or aromatic units, or together forming a divalent alkyl group having 1 to 10 carbon atoms and optionally also containing oxygen atoms, nitrogen atoms or aromatic units; R3 and R4 are independently hydrogen atoms or monovalent alkyl groups having 1 to 10 carbon atoms and optionally also containing oxygen atoms or nitrogen atoms; and the subscript n has a value of 1 or 2.

[0058] Preferably, R1 and R2 are independently hydrogen atoms or monovalent straight-chain or branched alkyl groups having 1 to 10, preferably 1 to 5, more preferably 1 to 4 carbon atoms and optionally together forming a divalent alkyl group with an adjacent nitrogen atom, and / or R3 and R4 independently represent hydrogen atoms or monovalent straight-chain or branched alkyl groups having 1 to 10, preferably 1 to 5, more preferably 1 to 4 carbon atoms and optionally together forming a divalent alkyl group with an adjacent nitrogen atom.

[0059] The most particularly preferred substituted urea of ​​formula (III) is one in which R1 and R2 in formula (III) are both hydrogen atoms and / or where R3 and R4 are both ethyl or methyl, preferably those that are methyl.

[0060] Accelerator C is particularly suitable for molecules with a molecular weight of less than 1000 g / mol, especially in the range of 80-800 g / mol. Larger molecular weights result in reduced accelerating effects and significantly higher required dosages, which can lead to poor mechanical properties.

[0061] Preferably, the ratio of accelerator C, expressed in grams, to the total number of epoxy groups per mole of liquid epoxy resin A1 and solid epoxy resin A2 is preferably 0.1-5.0 g / mol epoxy groups, especially 0.3-3.0 g / mol epoxy groups, more preferably 0.5-2.0 g / mol epoxy groups, and most preferably 0.6-1.0 g / mol epoxy groups.

[0062] The composition of the present invention further contains d) at least one core-shell polymer D1. The core-shell polymer D1 preferably has a rubbery core. The rubbery core preferably has a Tg below -20°C, more preferably below -50°C, and even more preferably below -70°C. Preferably, the Tg value (glass transition temperature) is determined using a dynamic mechanical thermal analyzer (DMTA).

[0063] Furthermore, the core-shell polymer preferably has at least one shell portion, which preferably has a Tg of at least 50°C.

[0064] The "core" refers to the interior of a core-shell polymer. The core can form the center of a core-shell polymer, or the inner shell or domain of a core-shell polymer.

[0065] The shell is the portion of the core-shell polymer outside the rubber core. The shell portion (or multiple portions) typically forms the outermost part of the core-shell polymer. The shell material is preferably grafted onto or cross-linked with the core, or both. The rubber core can constitute 50-95% of the weight of the core-shell polymer, especially 60-90%.

[0066] The core of the core-shell polymer can be a polymer or copolymer of a conjugated diene (such as butadiene) or a lower alkyl acrylate (such as n-butyl acrylate, ethyl acrylate, isobutyl acrylate, or 2-ethylhexyl acrylate). The core polymer may additionally contain up to 20% by weight of other comonomers (such as styrene, vinyl acetate, vinyl chloride, methyl methacrylate, etc.). The core polymer is optionally crosslinked. The core polymer optionally contains up to 5% of comonomers with two or more unequally reactive unsaturated sites, such as diallyl maleate, monoallyl fumarate, allyl methacrylate, etc., where at least one reactive site is non-conjugated.

[0067] The shell polymer, optionally chemically grafted or crosslinked to the rubber core, is preferably polymerized from at least one lower alkyl methacrylate, such as methyl methacrylate, ethyl methacrylate, or tert-butyl methacrylate. Homopolymers of these methacrylate monomers can be used. Furthermore, up to 40% by weight of the shell polymer can be formed from other monovinylene monomers such as styrene, vinyl acetate, vinyl chloride, methyl acrylate, ethyl acrylate, butyl acrylate, etc. The molecular weight of the grafted shell polymer is typically between 20,000 and 500,000.

[0068] Core-shell polymers can have number-average particle sizes of 10 to 300 nanometers, especially 75 to 250 nanometers, as determined by transmission electron spectroscopy.

[0069] Preferred types of core-shell polymers have reactive groups in the shell polymer that can react with epoxy resins or epoxy resin curing agents. For example, glycidyl groups provided by monomers such as glycidyl methacrylate are suitable.

[0070] A particularly preferred type of core-shell polymer is that described in EP1632533A1. Core-shell rubber particles as described in EP1632533A1 comprise a crosslinked rubber core, in most cases a crosslinked copolymer of butadiene, and a shell, which is preferably a copolymer of styrene, methyl methacrylate, glycidyl methacrylate, and optionally acrylonitrile. The core-shell rubber is preferably dispersed in a polymer or epoxy resin, also as described in EP1632533A1.

[0071] The core-shell polymer can be provided as a dispersion of particles in an epoxy resin. This dispersion may contain, for example, 10-50% by weight of the core-shell polymer, with the remainder being epoxy resin. The epoxy resin in this dispersion is preferably the aforementioned polyglycidyl polyphenol ether. Such dispersions include commercially available products such as Kane Ace™ MX-150, MX-154, MX-257, MX-134, MX-135, MX-136, MX-139, MX-267, MX-215, MX-217, MX-236, and MX-451, all from Kaneka Americas.

[0072] When the core-shell polymer is provided in the form of such a dispersion, only the weight of the core-shell polymer is included in the core-shell polymer of the present invention. The weights of the epoxy resin and the polyglycidyl polyphenol ether in this dispersion are included in the corresponding components of the present invention.

[0073] Preferably, based on the total weight of the thermosetting one-component epoxy resin composition, the proportion of at least one core-shell polymer D1 is 6-12% by weight, preferably 7-11% by weight, and more preferably 8-10% by weight. This is advantageous for high fatigue resistance and impact peel strength. This is readily apparent, for example, in the comparison of E1 with E2 and E3 in Table 2.

[0074] The compositions of the present invention further contain e) at least one end-capped polyurethane polymer D2.

[0075] It is preferably an end-closed polyurethane polymer D2 with blocking groups eliminated at temperatures above 100°C.

[0076] At least one end-closed polyurethane polymer D2 is preferably an end-closed polyurethane prepolymer of formula (IV).

[0077]

[0078] R 1 Here, p is a p-valence group of a straight-chain or branched polyurethane prepolymer that is capped with an isocyanate group after the terminal isocyanate group is removed, and p has a value of 2 to 8.

[0079] In addition, R 2 Substituents that are independently selected from the group consisting of:

[0080]

[0081] R here 5 R 6 R 7 and R 8 Each is independently alkyl, cycloalkyl, aralkyl, or arylalkyl, or R5 With R 6 Together, or R 7 With R 8 Together they form part of a ring with optional substitution of 4 to 7 elements.

[0082] In addition, R 9' and R 10 Each is independently alkyl or aralkyl or aralkyl or alkoxy or aralkyl or aralkyloxy, and R 11 It is an alkyl group.

[0083] R 12 R 13 and R 14 Each is independently an alkylene group having 2 to 5 carbon atoms and optionally having a double bond or a substituted alkylene group, or a phenylene group or a hydrogenated phenylene group.

[0084] R 15 R 16 and R 17 Each is independently H or alkyl or aryl or aralkyl, and R 18 It is an aralkyl or monocyclic or polycyclic aromatic group, substituted or unsubstituted, which optionally has an aromatic hydroxyl group.

[0085] Finally, R 4 It is a group containing a primary or secondary hydroxyl group of an aliphatic, alicyclic, aromatic, or aryliphatic epoxide after the removal of the hydroxyl and epoxy groups, and the value of m is 1, 2, or 3.

[0086] R 18 Especially considered first are phenols or polyphenols after the removal of hydroxyl groups, particularly bisphenols. Preferred examples of such phenols and bisphenols include phenol, cresol, resorcinol, catechol, cashew nut shell alcohol (3-pentadecanylphenol (from cashew nut shell oil)), nonylphenol, phenols that have been reacted with styrene or dicyclopentadiene, bisphenol A, bisphenol F, and 2,2'-diallyl bisphenol A. 18 Secondly, it is especially considered to be hydroxybenzyl alcohol and benzyl alcohol after the removal of the hydroxyl group.

[0087] If R 5 R 6 R 7 R 8 R 9 R 9' R 10 R 11 R 15 R 16 Or R 17 If it is an alkyl group, then its C1-C chains are especially straight or branched. 20 alkyl.

[0088] If R5 R 6 R 7 R 8 R 9 R 9' R 10 R 15 R 16 R 17 Or R 18 If it is an aralkyl group, then the moiety is especially a methylene-bonded aromatic group, particularly a benzyl group.

[0089] If R 5 R 6 R 7 R 8 R 9 R 9' Or R 10 If it is an alkylaryl group, then this is especially true for the C1-C phenylene bond. 20 Alkyl groups, such as tolyl or xylyl.

[0090] R 2 The preferred substituent is one of the following formula:

[0091] , and .

[0092] The following formula The preferred substituent is ε-caprolactam after removing the NH proton.

[0093] The following formula The preferred substituents are monophenols or polyphenols, especially bisphenols, after the removal of phenolic hydrogen atoms. This R... 2 Particularly preferred examples of the group are those selected from the following groups:

[0094] , , , , , , , and .

[0095] Here, the Y group is a saturated, aromatic, or olefinically unsaturated hydrocarbon group having 1-20 carbon atoms, particularly 1-15 carbon atoms. Preferred Y groups are allyl, methyl, nonyl, dodecyl, phenyl, alkyl ether, carboxylic acid ester, or unsaturated C groups having 1-3 double bonds. 15 -alkyl.

[0096] Most preferably, R 2 yes .

[0097] The end-closed polyurethane prepolymer of formula (IV) is formed by reacting isocyanate-terminated linear or branched polyurethane prepolymers with one or more isocyanate reactive compounds R. 2 H is prepared. If two or more such isocyanate reactive compounds are used, the reaction can proceed sequentially or with a mixture of these compounds.

[0098] The reaction is preferably carried out in such a manner that one or more isocyanate reactive compounds R 2 H is used in stoichiometry or in excess to ensure that all NCO groups have been converted.

[0099] With R 1 The polyurethane prepolymer based on isocyanate end groups can be composed of at least one diisocyanate or triisocyanate and a polymer Q having terminal amino, thiol, or hydroxyl groups. PM And / or by optionally substituted polyphenols Q PP preparation.

[0100] Suitable diisocyanates are aliphatic, cycloaliphatic, aromatic, or aryliphatic diisocyanates, especially commercial products such as methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), toluidine diisocyanate (TODI), isophorone diisocyanate (IPDI), trimethylhexamethylene diisocyanate (TMDI), 2,5- or 2,6-bis(isocyanate methyl)bicyclo[2.2.1]heptane, naphthalene-1,5-diisocyanate (NDI), and dicyclohexylmethyl diisocyanate (HDI). 12 MDI, p-phenylene diisocyanate (PPDI), m-tetramethylphenyl dimethyl diisocyanate (TMXDI), and their dimers are preferred. HDI, IPDI, MDI, or TDI are preferred.

[0101] Suitable triisocyanates are trimers or biurets of aliphatic, cycloaliphatic, aromatic, or aryliphatic diisocyanates, especially isocyanurates and biurets of the diisocyanates described in the preceding paragraph. Of course, mixtures of suitable diisocyanates or triisocyanates may also be used.

[0102] Especially suitable polymers Q with terminal amino, thiol or hydroxyl groups PM Q is a polymer having two or three terminal amino groups, thiols, or hydroxyl groups. PM .

[0103] Polymer Q PM Advantageously, it has an equivalent weight of 300-6000, especially 600-4000, preferably 700-2200 g / equivalent of NCO-reactive groups.

[0104] Preferred polymer Q PM It is a polyol with an average molecular weight of 600-6000 Daltons, selected from polyethylene glycol, polypropylene glycol, polyethylene glycol-polypropylene glycol block polymers, polybutanediol, hydroxyl-terminated polybutadiene, hydroxyl-terminated butadiene-acrylonitrile copolymers and mixtures thereof.

[0105] The preferred polymer Q PM It is an α,ω-dihydroxy polyalkylene glycol having C2-C6 alkylene groups or a mixture of C2-C6 alkylene groups, which is capped with amino, thiol, or preferably hydroxyl groups. Polypropylene glycol or polybutane glycol is particularly preferred. Hydroxyl-capped polybutene oxide is even more particularly preferred.

[0106] Especially suitable polyphenol Q PP These are bisphenols, triphenols, and tetraphenols. This is understood to refer not only to straight-chain phenols but also optionally to substituted phenols. The nature of the substitution can be very different. More specifically, this is understood to refer to substitution directly on an aromatic ring bonded to a phenolic OH group. Phenols are also understood not only to monocyclic aromatic compounds but also to polycyclic or fused aromatic compounds or heteroaromatic compounds having a phenolic OH group directly on an aromatic or heteroaromatic system.

[0107] In a preferred embodiment, the polyurethane prepolymer comprises at least one diisocyanate or triisocyanate and a polymer Q having terminal amino groups, thiols, or hydroxyl groups. PM Preparation. The polyurethane prepolymer is prepared in a manner known to those skilled in the art of polyurethane, particularly by using a method relative to polymer Q. PM Prepared by stoichiometric excess of amino, thiol or hydroxyl groups of diisocyanate or triisocyanate.

[0108] Polyurethane prepolymers with isocyanate end groups preferably exhibit elasticity. Their glass transition temperature (Tg) is preferably below 0°C.

[0109] Preferably, based on the total weight of the thermosetting one-component epoxy resin composition, the proportion of at least one end-closed polyurethane polymer D2 is 3.5-8% by weight, preferably 4-7.25% by weight, more preferably 4.5-7% by weight. This is advantageous for high fatigue resistance and impact peel strength. This is readily apparent in, for example, the comparison of E1 with E2 and E3 in Table 2.

[0110] The weight ratio (D1 / D2) of at least one core-shell polymer D1 to at least one end-closed polyurethane polymer D2 is 1.2-4.

[0111] It has been surprisingly found that ratios below 1.25 result in reduced fatigue resistance, Tg, tensile strength, and E-modulus values. This is readily apparent, for example, in the comparison of Ref1 with E1-E3 in Table 2. Further surprisingly, it has been found that ratios above 4 result in reduced fatigue resistance and impact peel strength values. This is readily apparent, for example, in the comparison of E1 with E2 and E3 in Table 2.

[0112] Preferably, the weight ratio (D1 / D2) of the at least one core-shell polymer D1 to the at least one end-closed polyurethane polymer D2 is 1.25-2.75, particularly 1.5-2.25. This is advantageous for high fatigue resistance and impact peel strength. This is readily apparent, for example, in the comparison of E1 with E2 and E3 in Table 2.

[0113] In another preferred embodiment, the composition further comprises at least one filler F. Preferred fillers include mica, talc, kaolin, wollastonite, feldspar, syenite, chlorite, bentonite, montmorillonite, calcium carbonate (precipitated or ground), dolomite, quartz, silica (fused or precipitated), cristobalite, calcium oxide, aluminum hydroxide, magnesium oxide, hollow ceramic beads, hollow glass beads, organic hollow beads, glass beads, and colored pigments. Fillers selected from calcium carbonate, calcium oxide, and pyrolytic silica are particularly preferred.

[0114] Advantageously, based on the total weight of the thermosetting one-component epoxy resin composition, the total proportion of total filler F is 5-30% by weight, preferably 10-25% by weight, and more preferably 12.5-20% by weight.

[0115] In another preferred embodiment, the composition further comprises at least one reactive diluent G with an epoxy group. Such reactive diluents are known to those skilled in the art. Preferred examples of reactive diluents with epoxy groups are:

[0116] - Monofunctional, saturated or unsaturated, branched or unbranched, cyclic or open-chain C4-C 30 Glycidyl ethers of alcohols, such as butanol glycidyl ether, hexanol glycidyl ether, 2-ethylhexanol glycidyl ether, allyl glycidyl ether, tetrahydrofurfuryl and furfuryl glycidyl ethers, trimethoxysilyl glycidyl ether, etc.

[0117] - Bifunctional, saturated or unsaturated, branched or unbranched, cyclic or open-chain C2-C 30 Glycidyl ethers of alcohols, such as ethylene glycol glycidyl ether, butylene glycol glycidyl ether, hexanediol glycidyl ether, octanediol glycidyl ether, cyclohexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, etc.

[0118] - Glycidyl ethers of trifunctional or polyfunctional, saturated or unsaturated, branched or unbranched, cyclic or open-chain alcohols, such as epoxidized castor oil, epoxidized trimethylolpropane, epoxidized pentaerythritol, or polyglycidyl ethers of aliphatic polyols such as sorbitol, glycerol, trimethylolpropane, etc.

[0119] - Glycidyl ethers of phenolic and aniline compounds, such as phenyl glycidyl ether, tolyl glycidyl ether, p-tert-butylphenyl glycidyl ether, nonylphenol glycidyl ether, 3-n-pentadecanenyl glycidyl ether (from cashew nut shell oil), N,N-diglycidyl aniline, etc.

[0120] - Epoxidized amines, such as N,N-diglycidylcyclohexylamine, etc.;

[0121] - Epoxidized mono or dicarboxylic acids, such as glycidyl neodecanoate, glycidyl methacrylate, glycidyl benzoate, diglycidyl phthalate, tetrahydrophthalate and hexahydrophthalate, diglycidyl esters of dimer fatty acids, etc.

[0122] - Epoxidized difunctional or trifunctional polyether polyols with low to high molecular weights, such as polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, etc.

[0123] Hexanediol diglycidyl ether, toluene diglycidyl ether, p-tert-butylphenyl diglycidyl ether, polypropylene glycol diglycidyl ether, and polyethylene glycol diglycidyl ether are particularly preferred.

[0124] Advantageously, based on the total weight of the thermosetting one-component epoxy resin composition, the total proportion of the epoxy-containing reactive diluent G is 0.1-15% by weight, preferably 0.1-5% by weight, particularly preferably 0.1-2% by weight, and more preferably 0.2-1% by weight.

[0125] The composition may include other components, particularly catalysts, stabilizers (especially heat and / or light stabilizers), thixotropic agents, plasticizers, solvents, mineral or organic fillers, foaming agents, dyes and pigments, corrosion inhibitors, surfactants, defoamers and adhesion promoters.

[0126] Suitable plasticizers, especially phenolic alkyl sulfonates or N-butylbenzamides, are available from Bayer as Mesamoll® or Delatol BBS.

[0127] Suitable stabilizers are especially optional substituted phenols, such as BHT or Wingstay® T (Elkem), sterically hindered amines, or N-oxygen compounds, such as TEMPO (Evonik).

[0128] Particularly preferred one-component epoxy resin compositions include:

[0129] -Based on the total weight of the thermosetting one-component epoxy resin composition, 37.5-55% by weight, more preferably 40-52.5% by weight, and most preferably 42.5-50% by weight of at least one liquid epoxy resin A1 having an average of more than one epoxy group per molecule;

[0130] -Based on the total weight of the thermosetting one-component epoxy resin composition, 10-25% by weight, more preferably 12.5-20% by weight, and most preferably 13.5-17.5% by weight of at least one solid epoxy resin A2 having an average of more than one epoxy group per molecule;

[0131] - At least one latent curing agent B for epoxy resin, wherein the latent curing agent B is selected from dicyandiamide, guanidine, guanidine, anhydrides of polycarboxylic acids and aminoguanidine, preferably dicyandiamide, and its amount is preferably 0.1-30% by weight, especially 1-20% by weight, preferably 5-15% by weight, particularly preferably 7.5-12.5% ​​by weight, based on the weight of epoxy resin A.

[0132] - Preferably, at least one accelerator C is selected from substituted urea, imidazole, imidazoline and blocked amine, especially substituted urea. Preferably, the proportion of accelerator C (based on the total number of epoxy groups in g / mol of liquid epoxy resin A1 and solid epoxy resin A2) is 0.1-5.0 g / mol epoxy groups, especially 0.3-3.0 g / mol epoxy groups, more preferably 0.5-2.0 g / mol epoxy groups, and most preferably 0.6-1.0 g / mol epoxy groups.

[0133] - At least one core-shell polymer D1, preferably having a number-average particle size of 10 to 300 nm, preferably 75 to 250 nm, as determined by transmission electron spectroscopy, and preferably in an amount of 6-12% by weight, preferably 7-11% by weight, and more preferably 8-10% by weight, based on the total weight of the thermosetting one-component epoxy resin composition;

[0134] - At least one end-closed polyurethane polymer D2, preferably an end-closed polyurethane polymer with a blocking group eliminated at a temperature above 100°C, preferably in an amount of 3.5-8% by weight, more preferably 4-7.25% by weight, more preferably 4.5-7% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0135] -Based on the total weight of the thermosetting one-component epoxy resin composition, preferably 55-30% by weight, more preferably 10-25% by weight, and more preferably 12.5-20% by weight of at least one filler F, which is preferably selected from calcium carbonate, calcium oxide and fumed silica;

[0136] -Based on the total weight of the thermosetting one-component epoxy resin composition, preferably 0.1-15% by weight, more preferably 0.1-5% by weight, particularly preferably 0.1-2% by weight, and even more preferably 0.2-1% by weight of the reactive diluent G with epoxy groups.

[0137] The weight ratio (A1 / A2) of at least one liquid epoxy resin A1 to at least one solid epoxy resin A2 is 1.75-3.75, preferably 1.9-3.25, and more preferably 2.25-3.25.

[0138] The weight ratio (D1 / D2) of at least one core-shell polymer D1 to at least one end-closed polyurethane polymer D2 is 1.2-4, preferably 1.25-2.75, and more preferably 1.5-2.25.

[0139] It may be further advantageous when the preferred single-component epoxy resin composition consists of more than 80% by weight, preferably more than 90% by weight, and especially more than 95% by weight of the above-mentioned components based on the total weight of the epoxy resin composition.

[0140] When the epoxy resin composition of the present invention has a viscosity of 1000-5500 Pa at 25°C s, especially 1500-5000Pa s, preferably 2000-4500Pa s, more preferably 2000-4000Pa This is advantageous, especially when using an oscillating rheometer with the following parameters: 5 Hz, 1 mm measurement gap, 25 mm plate-to-plate diameter, and 1% deformation. This is advantageous because it ensures good applicability.

[0141] It has been found that the aforementioned thermosetting one-component epoxy resin compositions are particularly suitable for use as one-component thermosetting adhesives, especially as thermosetting one-component body adhesives in motor vehicle construction. This one-component adhesive has a range of possible applications. This adhesive is required for bonding heat-stable materials. Heat-stable materials are understood to be materials that are dimensionally stable at a curing temperature of 100-220°C, preferably 120-200°C, at least during the curing time. In particular, these are metals and plastics, such as ABS, polyamides, polyphenylene ethers, composites such as SMC, unsaturated polyester GFP, epoxy or acrylate composites. The use of at least one of these materials as a metal is preferred. Particularly preferred applications are considered to be the bonding of the same or different metals, especially in the body construction of the automotive industry. Preferred metals are particularly steel, especially electrolytically galvanized, hot-dip galvanized or oiled steel, Bonazinc-coated steel and post-phosphated steel, and aluminum, especially in variants commonly found in automotive construction.

[0142] Using the adhesive based on the thermosetting one-component composition of the present invention, after initial curing at 180°C, particularly at 180-230°C, especially 190-220°C, preferably 200-210°C for 10-180 seconds, especially 20-80 seconds, preferably 30-60 seconds, when further heated to 180°C, sufficient adhesion of the bonding substrate can be ensured without additional metal bonding techniques.

[0143] This adhesive is particularly suitable for applications that do not use any metal joining techniques, especially thermal and mechanical metal joining techniques, more preferably welding and riveting. These applications preferably involve first pre-curing the adhesive at 180-230°C, especially 190-220°C, preferably 200-210°C, especially for 10-180 seconds, especially for 20-80 seconds, preferably for 30-60 seconds, and then, especially after cooling the pre-cured adhesive to below 60°C, further heating it to at least 160°C, especially at least 180°C, followed by complete curing of the adhesive.

[0144] This adhesive is first brought into contact with the material to be bonded at a temperature of 10°C to 80°C, especially 10°C to 60°C, and then pre-cured as described above and subsequently fully cured.

[0145] Another aspect of the present invention relates to a method for bonding a thermally stable substrate, comprising the following stages:

[0146] i) Apply the thermosetting one-component epoxy resin composition as described in detail above to the surface of the heat-stabilized substrate S1, especially the surface of a metal.

[0147] ii) To bring the applied thermosetting one-component epoxy resin composition into contact with the surface of another heat-stable substrate S2, especially a metal;

[0148] iii) Heating the composition to 180-230°C, especially 190-220°C, preferably 200-210°C, for 10-180 seconds, especially 20-80 seconds, preferably 30-60 seconds.

[0149] iv) Preferably, the composition is heated to a temperature of 100-220°C, especially 120-200°C, preferably 140-190°C, more preferably 150-180°C, wherein the composition reaches a temperature below 100°C, especially below 60°C, preferably 50-20°C between steps iii) and iv). Preferably, there is a time period of more than 15 minutes, especially more than 20 minutes, preferably ≥30 minutes, especially 30-300 minutes between steps iii) and iv).

[0150] Here, substrate S2 is composed of the same or different material as substrate S1. Substrate S1 and / or S2 are in particular the aforementioned metals and plastics.

[0151] Preferably, the heating in step iii) is by induction heating. More preferably, the heating in step iv) is in an oven, preferably in a paint curing oven, and particularly preferably in a paint curing oven for vehicles.

[0152] Preferably, in step iv), the composition is heated to a temperature of 100-220°C, especially 120-200°C, preferably 140-190°C, more preferably 150-180°C, and the composition is placed at the above temperature for 10 minutes to 6 hours, 10 minutes to 2 hours, 10 minutes to 60 minutes, 10 minutes to 30 minutes, 10 minutes to 20 minutes, more preferably 10 minutes to 15 minutes.

[0153] More preferably, in step i), the thermosetting one-component epoxy resin composition is applied to the surface of the heat-stabilized substrate S1 in the form of an adhesive strip, preferably having a length of 2-700 cm, more preferably 5-500 cm, and a diameter of 0.05-5 cm, more preferably 0.1-2 cm, and in step iii), the composition is heated to the specified time and temperature only over less than 50% of the entire length of the adhesive strip, preferably only over less than 20% of the entire length of the adhesive strip. In this method, induction curing of only a small amount of the applied adhesive strip is sufficient to ensure the structural integrity of the bonded article to be transported / stored until final curing, such as in step iv).

[0154] This method of bonding heat-stabilized materials yields bonded articles. These articles are preferably vehicles or parts thereof.

[0155] Therefore, another aspect of the invention relates to articles bonded by adhesives obtained by the above-described methods. Furthermore, the compositions of the invention are applicable not only to automotive constructions but also to other application areas. Particular mention should be made of their relevant applications in the construction of transportation vehicles (e.g., ships, trucks, buses, or rail vehicles) or in the construction of consumer products (e.g., washing machines).

[0156] Materials bonded by the adhesive according to the composition of the invention are used at temperatures typically from 120°C to -40°C, preferably from 100°C to -40°C, and particularly from 80°C to -40°C.

[0157] A particularly preferred use of the thermosetting one-component epoxy resin composition of the present invention is as a thermosetting one-component body adhesive in motor vehicle construction, or as a curing compound, or as a foamable thermosetting composition for reinforcing voids in structural components and reinforcing elements.

[0158] Another aspect of the present invention relates to a cured epoxy resin composition obtained by heating a thermosetting one-component epoxy resin composition as described in detail above.

[0159] Another aspect of the invention relates to the use of a combination of at least one liquid epoxy resin A1 and at least one solid epoxy resin A2 in a weight ratio of 1.75-3.75 (A1 / A2) and at least one core-shell polymer D1 and at least one end-closed polyurethane polymer D2 in a weight ratio of 1.2-4 (D1 / D2) for improving the fatigue resistance of a thermosetting one-component epoxy resin composition. The thermosetting one-component epoxy resin composition comprises:

[0160] - At least one liquid epoxy resin A1 having more than one epoxy group per molecule on average;

[0161] - At least one solid epoxy resin A2 having more than one epoxy group per molecule on average;

[0162] - At least one latent curing agent B for epoxy resins, wherein the latent curing agent B is selected from dicyandiamide, guanidine, guanidine, anhydrides of polycarboxylic acids and aminoguanidine, preferably dicyandiamide;

[0163] - at least one core-shell polymer D1; and

[0164] - At least one end-closed polyurethane polymer D2.

[0165] Components A1, A2, B, D1, and D2 are the components as described above, including preferred variants thereof, and preferably include the aforementioned preferred features. Fatigue resistance is measured as described in the experimental section. Improvement means higher fatigue resistance than the thermosetting one-component epoxy resin composition without the combination of the aforementioned weight ratios (A1 / A2) and (D1 / D2). Preferably, the improvement in fatigue resistance (number of cycles) is greater than 20%, more preferably greater than 30%.

[0166] More preferably, the composition of the present invention has the following properties:

[0167] After pre-curing at 200℃ for 35 seconds:

[0168] As described in the experiment, the LSS measured at room temperature was >8 MPa, particularly ≥10 MPa, and more preferably ≥12 MPa.

[0169] and / or

[0170] As described in the experiment, LSS measured at 180°C was >0.5 MPa, especially ≥1.0 MPa, especially ≥1.5 MPa.

[0171] After complete curing at 180℃ for 40 minutes:

[0172] As described in the experiment, the measured TS is ≥30MPa, especially ≥35MPa, especially ≥40MPa;

[0173] Elongation at break (EB), as measured in the experiment, was 4-20%;

[0174] The elastic modulus measured as described in the experiment is ≥1000MPa, especially ≥1500MPa, more preferably ≥2000MPa, and most preferably ≥2200MPa;

[0175] As described in the experiment, the measured Tg is ≥115℃, especially ≥120℃, more preferably ≥125℃;

[0176] As described in the experiment, the LSS measured at room temperature is >30 MPa, especially ≥32.5 MPa, more preferably ≥35 MPa.

[0177] and / or

[0178] As described in the experiment, LSS measured at 180°C was >0.5 MPa, especially ≥1.0 MPa, especially ≥1.5 MPa.

[0179] As described in the experiment, the IP measured at 23°C was ≥25 N / mm, especially ≥30 N / mm, and more preferably ≥35 N / mm;

[0180] As described in the experiment, the IP at -30°C is ≥10 N / mm, especially ≥15 N / mm, and more preferably ≥20 N / mm.

[0181] Example

[0182] The following references some embodiments that further illustrate the invention but are not intended to limit the scope of the invention in any way.

[0183] Preparation of toughness modifier ("D2")

[0184] 150 g of poly-THF 2000 (OH value 57 mg / g KOH) and 150 g of Liquiflex H (OH value 46 mg / g KOH) were dried under vacuum at 105 °C for 30 minutes. Once the temperature dropped to 90 °C, 61.5 g of IPDI and 0.14 g of dibutyltin dilaurate were added. The reaction was carried out under vacuum at 90 °C for 2.0 hours until the NCO content was constant at 3.10% (calculated NCO content: 3.15%). Subsequently, 96.1 g of cashew nut shell powder was added as a blocking agent. The mixture was stirred under vacuum at 105 °C until no free NCO could be detected. The product was used as is as toughening modifier D2.

[0185]

[0186] Preparation of the composition

[0187] Reference compositions Ref1 and Ref2, and compositions E1 to E6 of the present invention, were prepared according to the compositions in Table 1, wherein the amounts are in parts by weight. The bisphenol-A-based liquid epoxy resin present in 60% by weight of product Kane Ace MX 154 is calculated as part of liquid epoxy resin A1 in Table 1. The core-shell polymer blend containing 100 nm and 200 nm particles with a polybutadiene rubber core, present in 40% by weight of product Kane Ace MX 154, is calculated as core-shell polymer D1. The ratio of the molar amount of liquid epoxy resin A1 and solid epoxy resin A2 to the molar amount of the total epoxy groups of the epoxy-containing reactive diluent G / the molar amount of curing agent B ((A1+A2+G) / B) is 5.2. The ratio of the grams of accelerator C to the molar amount of the total epoxy groups of each mole of liquid epoxy resin A1 and solid epoxy resin A2 to the molar amount of the epoxy-containing reactive diluent G is 0.8 g / mol.

[0188] Test method:

[0189] Tensile strength (TS), elongation at break (EB), and modulus of elasticity (E-modulus) (DIN EN ISO 527)

[0190] The adhesive sample was pressed between two sheets of Teflon paper to form a 2 mm thick layer. After curing at 180°C for 40 minutes, the Teflon paper was removed, and the sample was die-cut to DIN standard dimensions. The test sample was examined under standard climatic conditions at a strain rate of 2 mm / min. Tensile strength (ZF), elongation at break, and modulus of elasticity (0.05–0.25%) were measured at 23°C according to DIN EN ISO 527.

[0191] Overlap shear strength induction curing Tmax 200℃ (LSS ind1) (DIN EN 1465)

[0192] A clean Elo H420 steel sample (1.5 mm thick) that had been re-oiled with Anticorit PL 3802-39S was bonded to a 25 × 10 mm bonding area with an adhesive layer of 0.3 mm thickness using glass beads as spacers. The sample was then heated to 200 °C within 10 seconds using an induction system (EW2 laboratory induction system, manufacturer: IFF GmbH, Germany) and held at 200 °C for 35 seconds (target temperature). Afterward, the sample was heated to 120 °C within 10 seconds using compressed air and then cooled to 23 °C.

[0193] The lap shear strength was determined using a tensile testing machine at a strain rate of 10 mm / min at a temperature of 23°C (“LSSind1@RT”) or at a temperature of 180°C (“LSSind1@180°C”) according to DIN EN 1465.

[0194] Overlap shear strength induction curing Tmax 210℃ (LSS ind2) (DIN EN 1465)

[0195] A clean Elo H420 steel sample (1.5 mm thick), which had been re-oiled with Anticorit PL 3802-39S, was bonded to a 25 × 10 mm bonding area with an adhesive layer of 0.3 mm thickness using glass beads as spacers. The sample was then heated to 210 °C within 10 seconds using an induction system (EW2 laboratory induction system, manufacturer: IFF GmbH, Germany) and held at 210 °C for 35 seconds (target temperature). Afterward, the sample was heated to 120 °C within 10 seconds using compressed air and then cooled to 23 °C.

[0196] The lap shear strength was determined using a tensile testing machine at a strain rate of 10 mm / min, at a temperature of 23°C (“LSSind2@RT”) or at a temperature of 180°C (“LSS ind2@180°C”) according to DIN EN 1465.

[0197] Overlap shear strength test: oven cured for 40 min at 180°C (LSS) (DIN EN 1465)

[0198] Clean samples of Elo H420 steel (1.5 mm thick) that had been re-oiled with Anticorit PL 3802-39S were bonded with adhesive using glass beads as spacers in a 25 × 10 mm bonding area with a layer thickness of 0.3 mm, and cured in an oven at 180°C for 40 minutes.

[0199] The lap shear strength was determined on a tensile testing apparatus at a strain rate of 10 mm / min in a triple test according to DIN EN 1465 at a temperature of 23°C (“LSS@RT”) or at a temperature of 180°C (“LSS@180°C”).

[0200] Impact peel strength (IP@23℃ / -30℃) (ISO 11343)

[0201] Specimens were prepared using adhesive and DC04+ZE steel with dimensions of 90 × 20 × 0.8 mm. The adhesive area was 20 × 30 mm, with a layer thickness of 0.3 mm, and glass beads were used as spacers. The samples were cured in an oven at 180 °C for 40 minutes. Impact peel strength was measured at 23 °C or -30 °C using a triple test on a Zwick 450 impact pendulum. The recorded impact peel strength is the average force, expressed in N / mm, based on the measurement curve from 25% to 90% according to ISO 11343.

[0202] Determination of fatigue resistance ("fatigue")

[0203] Fatigue testing was conducted at a single stress level (i.e., one point on the "Wöhler" curve). The maximum load was set at 6 kN, and the stress amplitude was set at + / - 2.7 kN, resulting in an R value of 0.1. For testing purposes, according to... Figure 1 The lap shear test specimens were prepared as shown. The adhesive was cured at 180°C for 20 minutes. The substrate used was coated with 3 g / m... 2 Anticorit PL 3802-39S is made of 1.2 mm thick galvanized steel (H420). The results (fatigue cycles up to failure, “fatigue”) are averages obtained from measurements of 5 individual samples.

[0204] Viscosity

[0205] One day after preparation on an Anton Paar MCR 101 rheometer, the viscosity of the adhesive was measured by oscillation at 25°C using a plate-to-plate geometry with the following parameters: 5 Hz, 1 mm measurement gap, 25 mm plate-to-plate diameter, and 1% deformation. The analyzed compositions R1-R2 and E1-E6 all exhibited viscosity ranging from 2000 to 4000 Pa. The viscosity of s.

[0206]

[0207] Table 1, nd = not determined

[0208]

[0209] Table 2: nd = Not determined.

Claims

1. A thermosetting one-component epoxy resin composition comprising: a) At least one liquid epoxy resin A1, having an average of more than one epoxy group per molecule, wherein the amount is preferably 37.5-55% by weight, more preferably 40-52.5% by weight, and most preferably 42.5-50% by weight, based on the total weight of the thermosetting one-component epoxy resin composition. b) At least one solid epoxy resin A2, having an average of more than one epoxy group per molecule, preferably in an amount of 10-25% by weight, more preferably 12.5-20% by weight, and most preferably 13.5-17.5% by weight, based on the total weight of the thermosetting one-component epoxy resin composition. c) At least one latent curing agent B for epoxy resin, wherein the latent curing agent B is selected from dicyandiamide, guanidine, guanidine, anhydrides of polycarboxylic acids and aminoguanidine, preferably dicyandiamide; d) At least one core-shell polymer D1; and e) At least one end-closed polyurethane polymer D2; The weight ratio (A1 / A2) of the at least one liquid epoxy resin A1 to the at least one solid epoxy resin A2 is 1.75-3.75, and the weight ratio (D1 / D2) of the at least one core-shell polymer D1 to the at least one end-closed polyurethane polymer D2 is 1.2-4.

2. The thermosetting one-component epoxy resin composition according to claim 1, characterized in that... The weight ratio (A1 / A2) of the at least one liquid epoxy resin A1 to the at least one solid epoxy resin A2 is 1.9-3.25, preferably 2.25-3.

25.

3. The thermosetting one-component epoxy resin composition as described in any one of the preceding claims, characterized in that... The weight ratio (D1 / D2) of the at least one core-shell polymer D1 to the at least one end-closed polyurethane polymer D2 is 1.25-2.75, particularly 1.5-2.

25.

4. The thermosetting one-component epoxy resin composition as described in any one of the preceding claims, characterized in that... The thermosetting one-component epoxy resin composition further includes at least one accelerator C, the accelerator being selected from the list of substituted ureas, imidazoles, imidazolines and blocked amines, especially substituted ureas.

5. The thermosetting one-component epoxy resin composition according to claim 4, characterized in that... The ratio of accelerator C, expressed in grams, to the total number of epoxy groups per mole of liquid epoxy resin A1 and solid epoxy resin A2 is preferably 0.1-5.0 g / mol epoxy groups, especially 0.3-3.0 g / mol epoxy groups, more preferably 0.5-2.0 g / mol epoxy groups, and most preferably 0.6-1.0 g / mol epoxy groups.

6. The thermosetting one-component epoxy resin composition as described in any one of the preceding claims, characterized in that, Based on the total weight of the thermosetting one-component epoxy resin composition, the proportion of the at least one liquid epoxy resin A1 is 37.5-55% by weight, more preferably 40-52.5% by weight, and most preferably 42.5-50% by weight; and / or, preferably, the proportion of the at least one solid epoxy resin A2 is 10-25% by weight, preferably 12.5-20% by weight, and more preferably 13.5-17.5% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

7. The thermosetting one-component epoxy resin composition as described in any one of the preceding claims, characterized in that... The proportion of the at least one core-shell polymer D1 is 6-12% by weight, preferably 7-11% by weight, more preferably 8-10% by weight, based on the total weight of the thermosetting one-component epoxy resin composition; and / or, preferably, the proportion of the at least one end-closed polyurethane polymer D2 is 3.5-8% by weight, preferably 4-7.25% by weight, more preferably 4.5-7% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

8. The thermosetting one-component epoxy resin composition as described in any one of the preceding claims, characterized in that... The at least one core-shell polymer D1 has a number-average particle size of 10 to 300 nm, preferably 75 to 250 nm, as determined by transmission electron spectroscopy; and / or, preferably, the at least one end-blocked polyurethane polymer D2 is an end-blocked polyurethane polymer with blocking groups eliminated at temperatures above 100°C.

9. The thermosetting one-component epoxy resin composition as described in any one of the preceding claims, characterized in that... The thermosetting one-component epoxy resin composition further comprises at least one filler F, based on the total weight of the thermosetting one-component epoxy resin composition, at 5-30% by weight, preferably 10-25% by weight, more preferably 12.5-20% by weight, wherein the filler is preferably selected from calcium carbonate, calcium oxide and fumed silica.

10. The thermosetting one-component epoxy resin composition according to any one of claims 1 to 9 as a one-component thermosetting adhesive, particularly as a thermosetting one-component body adhesive in motor vehicle construction.

11. A method for bonding a heat-stabilized substrate, comprising the following steps: i) Applying the thermosetting one-component epoxy resin composition as described in any one of claims 1 to 9 to a thermally stable substrate S1, particularly a metal surface; ii) To bring the applied thermosetting epoxy resin composition into contact with another thermally stable substrate S2, particularly a metal surface; iii) Heating the composition to 180-230°C, especially 190-220°C, preferably 200-210°C, for 10-180 seconds, especially 20-80 seconds, preferably 30-60 seconds. iv) Preferably, the composition is heated to a temperature of 100-220°C, especially 120-200°C, preferably 140-190°C, more preferably 150-180°C, wherein the composition reaches a temperature below 100°C, especially below 60°C, preferably 50-20°C between steps iii) and iv). The substrate S2 is composed of the same material as or a different material from the substrate S1.

12. The method of claim 11, wherein there is a time period of more than 15 minutes, especially more than 20 minutes, preferably ≥30 minutes, and especially 30 to 300 minutes between step iii) and step iv).

13. The method of claim 11 or 12, wherein the heating in step iii) is performed by induction heating.

14. The method as claimed in claims 11 to 13, wherein, In step iv), where the composition is heated to a temperature of 100-220°C, particularly 120-200°C, preferably 140-190°C, more preferably 150-180°C, the composition is placed at the above temperature for 10 minutes to 6 hours, 10 minutes to 2 hours, 10 minutes to 60 minutes, 10 minutes to 30 minutes, 10 minutes to 20 minutes, more preferably 10 minutes to 15 minutes, preferably in a paint curing oven, particularly preferably in a paint curing oven for vehicles.

15. An article bonded by an adhesive obtained by any one of claims 11 to 14.

16. Use of a combination of at least one liquid epoxy resin A1 in a weight ratio of 1.75-3.75 to at least one solid epoxy resin A2 (A1 / A2) and at least one core-shell polymer D1 in a weight ratio of 1.2-4 to at least one end-closed polyurethane polymer D2 (D1 / D2) for improving the fatigue resistance of a thermosetting one-component epoxy resin composition, wherein the fatigue resistance is measured as described in the experimental section, wherein the improvement in fatigue resistance (cycle count) is compared with the thermosetting one-component epoxy resin composition not having the combination of said weight ratios (A1 / A2) and (D1 / D2), and wherein the thermosetting one-component epoxy resin composition comprises: - At least one liquid epoxy resin A1 having more than one epoxy group per molecule on average; - At least one solid epoxy resin A2 having more than one epoxy group per molecule on average; - At least one latent curing agent B for epoxy resins, wherein the latent curing agent B is selected from dicyandiamide, guanidine, guanidine, anhydrides of polycarboxylic acids and aminoguanidine, preferably dicyandiamide; - at least one core-shell polymer D1; and - At least one end-closed polyurethane polymer D2; Preferably, the improvement in fatigue resistance (number of cycles) is greater than 20%, more preferably greater than 30%.

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