Thermally curable epoxy resin compositions with improved impact peel values

Abstract

The present invention relates to a thermosetting one-component epoxy resin composition comprising at least one epoxy resin, at least one latent curing agent for the epoxy resin, preferably at least one toughness improver and thermoplastic particles TP having an average particle size D50 between 5 and 400 pm determined by laser diffraction and a polar component of the surface free energy greater than 2 mN / m determined with the Washburn method. These thermosetting one-component epoxy resin compositions exhibit improved mechanical properties, in particular tensile strength and elastic modulus, as well as high impact peel values and provide good storage stability, in particular at elevated temperatures.

Description

Technical Field

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

[0002] Thermosetting one-component epoxy adhesives have been used in vehicle body construction for quite some time. Therefore, an important application area for one-component thermosetting epoxy adhesives is in vehicle construction, where metal substrates such as steel and aluminum are often present, especially in adhesive bonding applications. After the epoxy resin composition is applied, the vehicle body is heated in a CEC (cathode eccentric coating) oven, thereby curing the thermosetting epoxy resin composition. Good mechanical properties are required in adhesive bonding applications, especially tensile strength and modulus of elasticity, as well as high impact peel strength. Summary of the Invention Invention Overview

[0004] Therefore, one object of the present invention is to provide a thermosetting one-component epoxy resin composition having improved mechanical properties, particularly tensile strength and modulus of elasticity, as well as a high impact peel value, and preferably providing good storage stability, especially at elevated temperatures.

[0005] Surprisingly, this objective is achieved through the thermosetting one-component epoxy resin composition according to claim 1. This epoxy resin composition exhibits particularly good usability as a one-component thermosetting adhesive, especially as a thermosetting one-component body adhesive in motor vehicle construction.

[0006] Embodiments of the present invention

[0007] In a first aspect, the present invention relates to a thermosetting one-component epoxy resin composition comprising:

[0008] a) At least one epoxy resin A having an average of more than one epoxy group per molecule, preferably 10-60% by weight, more preferably 30-60% by weight, and most preferably 40-45% by weight, based on the total weight of the thermosetting one-component epoxy resin composition;

[0009] b) At least one latent curing agent B for epoxy resin, preferably, said latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1, aliphatic dicarboxylic acid dihydrazide B2 and dicyandiamide B3;

[0010] c) Preferably at least one toughness modifier D, preferably at least one end-closed polyurethane polymer D1; and

[0011] d) Thermoplastic particles TP having an average particle size D between 5-400 μm, preferably between 7.5-150 μm, and more preferably between 10-100 μm, as determined by laser diffraction, more preferably by using a Sympatec HELOS machine and dry air dispersion (RODOS). 50 , and the polar component of the surface free energy greater than 2 mN / m determined using the Washburn method as described below.

[0012] In this document, the use of the term “independently” in relation to substituents, radicals, or groups should be interpreted as meaning that substituents, radicals, or groups with the same name in the same molecule may appear simultaneously with different meanings.

[0013] In this article, the prefix "poly" in substance names such as "polyol", "polyisocyanate", "polyether" or "polyamine" indicates that the corresponding substance contains more than one functional group per molecule that appears in its name in a formal sense.

[0014] In this article, "molecular weight" is understood to refer to the molar mass of a molecule (in grams per mole). "Average molecular weight" is understood to refer to the number-average molecular weight M of oligomers or polymer mixtures. n It is usually determined using polystyrene as a standard by GPC, unless otherwise stated.

[0015] "Primary hydroxyl group" refers to an OH group bonded to a carbon atom with two hydrogen atoms.

[0016] In this document, 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, which may together form 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."

[0017] In this article, "room temperature" refers to a temperature of 23°C.

[0018] This thermosetting one-component epoxy resin composition contains d) thermoplastic particles TP having an average particle size D, determined by laser diffraction, between 5-400 μm, preferably between 7.5-150 μm, and more preferably between 10-100 μm. 50 More preferably, the average particle size D is determined using a Sympatec HELOS machine and a dry airflow dispersion (RODOS) apparatus. 50 Most preferably, the average particle size D is determined as described in the experimental section. 50 .

[0019] Thermoplastic particles (TP) have a polar component of surface free energy greater than 2 mN / m, as determined by the Washburn method.

[0020] Surprisingly, it was found that thermoplastic particles (TP) with a surface free energy greater than 2 mN / m exhibited superior mechanical properties, particularly elastic modulus and tensile strength, compared to compositions containing toughness modulators, preferably end-closed polyurethane polymers. Thermoplastic particles (TP) with a surface free energy less than 2 mN / m showed significantly lower values. Particularly surprisingly, it was further found that, unlike particles with a surface free energy less than 2 mN / m, thermoplastic particles (TP) with a surface free energy greater than 2 mN / m exhibited high impact peel values. This can be seen, for example, in the comparison of Ref. 1 and Ref. 2 with E1 to E4 in Table 2, or in the comparison of Ref. 3 and Ref. 4 with E5 to E8.

[0021] Particularly preferred are the thermoplastic particles TP having a polar component of surface free energy greater than 3 mN / m, preferably greater than 4.5 mN / m, and most preferably greater than 5.5 mN / m as determined by Washburn. This is advantageous for high impact peel values. This can be seen, for example, in Table 2 in the comparisons between Ref. 2 and E1 and E2, E1 and E2, Ref. 4 and E5 and E6, and E5 and E6. It is also shown in Table 4 in the comparisons between E9-E11 and E12-E14 and with E15-E17. It is further shown in Table 6 in the comparisons between E18-E19 and E20-E21.

[0022] Further preferably, in the thermoplastic particles TP, the polar component of the surface free energy accounts for more than 10%, preferably more than 15%, and more preferably more than 22.5% of the total surface free energy, wherein the total surface free energy is the sum of the polar and dispersive components of the surface free energy. The surface free energy is determined using the Washburn method. This is also advantageous for high impact peel values. This can be seen, for example, in Table 2 in the comparisons between Ref. 2 and E1 and E2, E1 and E2, Ref. 4 and E5 and E6, and E5 and E6. It is also shown in Table 4 in the comparisons between E9-E11 and E12-E14 and with E15-E17. It is further shown in Table 6 in the comparisons between E18-E19 and E20-E21.

[0023] In this invention, the Washburn method is performed as follows: In a Washburn measurement, a glass tube having a filter bottom filled with powder (in this case, particles) is brought into contact with the test liquid. The liquid is drawn in due to capillary action. During the measurement, the increase in the mass of the tube suspended on a force sensor is measured relative to time. If the bulk powder is considered as a bundle of capillaries, the process can be described by the Washburn equation:

[0024]

[0025] Where: m → liquid mass; t → flow time (absorption time); σ → surface tension of the liquid; c → capillary constant of the powder; ρ → density of the liquid; θ → contact angle; η → viscosity of the liquid.

[0026] The capillary constant c includes the number of microcapillaries and their average radius, and depends on the properties of the powder and the measuring tube. The measuring tube used is made of glass and has an inner diameter of 10 ± 0.2 mm, a total length of 50 mm, and a maximum fill length of 30 mm.

[0027] According to the Washburn equation, the constant c of the powder must be known, and therefore must be determined experimentally. To determine the constant c, measurements are taken using the optimal wetting (spreading) liquid (n-heptane in this application), where the contact angle θ is considered to be 0° (cosθ = 1). Substituting the value of c into the equation, the contact angle θ is determined using water and diiodomethane as test liquids. The contact angle measured in this way is the advance angle. In these cases, the density ρ and viscosity η of the liquid at a temperature of 23°C are considered.

[0028] The preparation of powder in the Washburn tank was performed according to a rigorous protocol. A certain amount of powder was compressed in the tank at 3-minute intervals using the gravitational effect of a 1 kg weight placed at the top of the tank. Afterward, the weight was carefully removed from the tank, and the tank was transferred to a tensiometer for Washburn measurements. To ensure that the powder height in the tank remained nearly constant after compaction, approximately 740–810 mg of powder was weighed using a microbalance. For all types of powder, the corresponding amount of powder yielded a powder column of approximately 18–22 mm at the end of compaction.

[0029] A glass graduated cylinder was connected to an electronic balance, and weight data vs. time were recorded at a frequency of 25 Hz as absorption occurred. Data acquisition began when the graduated cylinder came into contact with the test liquid. The liquid front should rise uniformly through the porous sample to increase the weight (avoiding air bubbles at the liquid / cylinder interface). These measurements were performed on a Kruss Modular tensiometer K100 MK3. To achieve reproducibility of the absorption measurements, the following conditions were desired:

[0030] - All measurements were performed at a constant temperature of 23°C.

[0031] - The temperature and relative humidity of the air near the measuring cylinder in the tension meter device are controlled at 23°C and 50% relative humidity.

[0032] - The total amount of solid particles is maintained at a filling height of approximately 18-22 mm.

[0033] The thermoplastic particles TP are preferably selected from polyolefin particles, more preferably polyethylene particles, polypropylene particles; polybutene particles, polymethylpentene particles and ethylene copolymer particles; polyethylene terephthalate particles; polybutylene terephthalate particles; polycarbonate particles and polyphenylene sulfide particles, preferably polyolefin particles, more preferably polyethylene particles.

[0034] The preferred polyethylene particles are selected from UHMWPE (ultra-high molecular weight polyethylene) particles, HMWPE (high molecular weight polyethylene) particles, HDPE (high-density polyethylene) particles, MDPE (medium-density polyethylene) particles and LDPE (low-density polyethylene) particles.

[0035] Particularly preferred thermoplastic particles TP are UHMWPE (ultra-high molecular weight polyethylene) particles, preferably having a viscosity-average molecular weight M of 1 million to 11 million g / mol, more preferably 3 million to 10.5 million g / mol, and even more preferably 3 million to 7 million g / mol. v Among them, the viscosity-average molecular weight M v The viscosity was determined using the Margolies equation based on the viscosity value measured according to ISO 1628, Part 3 (Revision 2010).

[0036] Further preferably, the thermoplastic particles TP have an outer surface that is at least partially oxidized, preferably obtained by chemical oxidation in the presence of KOCl, H2O2 or NaOCl solution, by plasma treatment or by an oxyfluorination process.

[0037] Preferred thermoplastic particles (TP) are commercially available, such as surface-modified polyolefin particles from Inhance, including those from the family described as the INHANCE® UH-1000 and HD-1000 series particles. Specific representatives of this family include those designated as UH-1045, UH-1080, UH-1200, UH-1250, UH-1500, and UH-1700.

[0038] Preferably, based on the total weight of the thermosetting one-component epoxy resin composition, the amount of thermoplastic particles (TP) is 2.5-30% by weight, preferably 5-22.5% by weight, and more preferably 7.5-15% by weight. This is advantageous for high impact peel values. This can be seen, for example, in Table 4 in the comparisons of E9 with E10 / E11, E12 with E13 / E14, and E15 with E16 / E17, respectively. It can also be seen, for example, in Table 6 in the comparisons of E18 with E19 and E20 with E21, respectively.

[0039] Epoxy resin A having an average of more than one epoxy group per molecule is preferably a liquid epoxy resin or a solid epoxy resin. The term "solid epoxy resin" is well known to those skilled in the art of epoxy resins and is used in contrast to "liquid epoxy resin". Solid resins have a glass transition temperature higher than room temperature, meaning they can be pulverized at room temperature to obtain a free-flowing powder.

[0040] Preferred epoxy resins have formula (II)

[0041]

[0042] The substituents R' and R'' are independently H or CH3.

[0043] In solid epoxy resins, the index s has a value > 1.5, especially values ​​between 2 and 12.

[0044] Such solid epoxy resins are available from suppliers such as Dow, Huntsman, or Hexion.

[0045] Compounds of formula (II) having an index s of 1 to 1.5 are referred to by those skilled in the art as semi-solid epoxy resins. For the purposes of this invention, they are also considered as solid resins. However, the preferred solid epoxy resins are epoxy resins in a narrower sense, i.e., where the index s has a value > 1.5.

[0046] In liquid epoxy resin, the index s has a value less than 1. Preferably, s has a value less than 0.2.

[0047] Therefore, diglycidyl ether of bisphenol A (DGEBA), diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol A / F are preferred. Such liquid resins can be obtained, for example, as Araldite® GY 250, Araldite® PY 304, Araldite® GY 282 (Huntsman), or DER™ 331 or DER™ 330 (Dow), or Epikote 828 (Hexion).

[0048] Another suitable epoxy resin A is the so-called epoxy phenolic varnish. More specifically, these are phenol or cresol epoxy phenolic varnishes.

[0049] Such epoxy resins are available under the trade names EPN or ECN and Tactix® from Huntsman, or in the DEN™ product line from Dow Chemical.

[0050] Epoxy resin A is preferably an epoxy resin of formula (II), especially a liquid epoxy resin of formula (II).

[0051] In a particularly preferred embodiment, the thermosetting one-component epoxy resin composition contains at least one liquid epoxy resin of formula (II) with s < 1, especially less than 0.2 and at least one solid epoxy resin of formula (II) with s > 1.5, especially 2 to 12.

[0052] Based on the total weight of the thermosetting one-component epoxy resin composition, the proportion of epoxy resin A is preferably 10-60% by weight, more preferably 30-60% by weight, and most preferably 40-55% by weight.

[0053] It is further advantageous that 50-100% by weight, especially 75-100% by weight, and more preferably 75-95% by weight, of epoxy resin A is the aforementioned liquid epoxy resin.

[0054] It is further advantageous that 0-30% by weight, particularly 0-25% by weight, and more preferably 5-25% by weight, of epoxy resin A is the aforementioned solid epoxy resin.

[0055] The compositions of the present invention further contain b) at least one latent curing agent B for epoxy resins. The latent curing agent is substantially inert at room temperature and is activated by elevated temperature, typically 70°C or higher, thereby initiating the curing reaction. Conventional latent curing agents for epoxy resins can be used. Nitrogen-containing latent curing agent B is preferred.

[0056] Preferably, the latent curing agent B is selected from dicyandiamide, dihydrazide, guanidine, guanidine, anhydrides of polycarboxylic acids, and aminoguanidine; more preferably, the latent curing agent B is selected from dicyandiamide and dihydrazide.

[0057] Particularly preferred is that the latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1 and aliphatic dicarboxylic acid dihydrazide B2, with aliphatic dicarboxylic acid dihydrazide B2 being preferred. This is advantageous for achieving a high room temperature impact peel value after 10 minutes at a curing temperature of 140°C. This can be seen, for example, in the comparison of E1-E4 with E5-E8 in Table 2.

[0058] It is also particularly preferred that the latent curing agent B is dicyandiamide B3.

[0059] This is advantageous for high room temperature impact peel values ​​achieved at a curing temperature of 195°C for 30 minutes. This can be seen, for example, in the comparison between E1-E4 and E5-E8 in Table 2.

[0060] When the latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1 and aliphatic dicarboxylic acid dihydrazide B2, the amount of latent curing agent B used in the epoxy resin is preferably 2 to 15% by weight, more preferably 6 to 14% by weight, and particularly 8 to 12% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0061] When the latent curing agent B is dicyandiamide B3, the amount of latent curing agent B used in the epoxy resin is preferably 0.5 to 12% by weight, more preferably 1 to 8% by weight, and particularly 2 to 6% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0062] Preferably, the thermosetting epoxy resin composition further contains at least one accelerator C for epoxy resin. Preferably, the accelerator C for epoxy resin is selected from substituted ureas, imidazoles, imidazolines, and blocked amines, preferably substituted ureas, and more preferably aliphatic substituted ureas.

[0063] When the latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1 and aliphatic dicarboxylic acid dihydrazide B2, the fraction of accelerator C for the epoxy resin is preferably 0.005-0.5% by weight, more preferably 0.01-0.2% by weight, and most preferably 0.02-0.1% by weight, based on the total weight of the thermosetting epoxy resin composition.

[0064] When the latent curing agent B is dicyandiamide B3, the fraction of accelerator C for the epoxy resin is preferably 0.05-2% by weight, more preferably 0.1-1% by weight, and most preferably 0.15-0.5% by weight, based on the total weight of the thermosetting epoxy resin composition.

[0065] The one-component thermosetting epoxy resin composition preferably contains at least one toughness modifier D. Toughness modifier D can be solid or liquid.

[0066] More specifically, the toughness modifier D is selected from end-closed polyurethane polymer D1, liquid rubber D2, and core-shell polymer D3. The toughness modifier D is preferably selected from end-closed polyurethane polymer D1 and liquid rubber D2. End-closed polyurethane polymer D1 is particularly preferred.

[0067] If the toughness modifier D is an end-blocked polyurethane prepolymer D1, it is preferably an end-blocked polyurethane polymer D1 with blocking groups eliminated at temperatures above 100°C.

[0068] Preferred blocking groups are, in particular, phenols or bisphenols. Preferred examples of such phenols and bisphenols are especially 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'-diallylbisphenol A.

[0069] Terminally blocked polyurethane prepolymers are prepared by reacting linear or branched polyurethane prepolymers terminally bound with isocyanate groups with one or more isocyanate reactive compounds. If two or more such isocyanate reactive compounds are used, the reaction can be carried out sequentially or with a mixture of these compounds.

[0070] The reaction is preferably carried out with one or more isocyanate reactive compounds in stoichiometric or stoichiometric excess form to ensure that all NCO groups have been converted.

[0071] Polyurethane prepolymers with 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.

[0072] Suitable diisocyanates are aliphatic, alicyclic, aromatic, or aryliphatic diisocyanates, especially commercial products such as diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), toluidine diisocyanate (TODI), isophorone diisocyanate (IPDI), trimethyl hexamethylene diisocyanate (TMDI), 2,5- or 2,6-bis(isocyanate methyl)bicyclo[2.2.1]heptane, naphthalene 1,5-diisocyanate (NDI), dicyclohexylmethyl diisocyanate (HDI). 12 MDI, terephthalic diisocyanate (PPDI), m-tetramethylphenyl dimethyl diisocyanate (TMXDI), and their dimers. HDI, IPDI, MDI, or TDI are preferred.

[0073] Suitable triisocyanates are trimers or biurets of aliphatic, alicyclic, aromatic, or aryliphatic diisocyanates, especially isocyanurates and biurets of diisocyanates described in the preceding paragraph. Of course, suitable mixtures of diisocyanates or triisocyanates may also be used.

[0074] 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 .

[0075] Polymer Q PM Advantageously, it has an equivalent of 300-6000, especially 600-4000, and preferably 700-2200 g / equivalent NCO reactive groups.

[0076] Preferred polymer Q PMIt is a polyol with an average molecular weight of 600 to 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.

[0077] The preferred polymer Q PM It is an α,ω-dihydroxy polyalkylene glycol having C2-C6-alkylene or mixed C2-C6-alkylene groups, which is capped with amino, thiol, or preferably hydroxyl groups. Polypropylene glycol or polybutane glycol is particularly preferred. More particularly preferred are hydroxyl-capped polyoxybutylene.

[0078] Especially suitable polyphenol Q PP These are bisphenols, triphenols, and tetraphenols. This is understood to refer not only to pure (straight) phenols, but optionally to substituted phenols. The nature of the substitution can be very diverse. More specifically, this is understood to refer to substitution directly on the aromatic ring to which the phenolic OH group is bonded. Phenols are also understood not only to monocyclic aromatic compounds, but also to polycyclic or fused aromatic compounds or heteroaromatic compounds having phenolic OH groups directly on the aromatic or heteroaromatic system.

[0079] 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 means of polymer Q. PM The amino, thiol or hydroxyl groups are treated with an excess of stoichiometric amounts of diisocyanate or triisocyanate.

[0080] Polyurethane prepolymers with isocyanate end groups preferably exhibit elastic characteristics. They preferably exhibit a glass transition temperature (Tg) below 0°C.

[0081] Toughness modifier D can be liquid rubber D2. This can be, for example, a polymer with carboxyl or epoxy groups at the end.

[0082] In a first embodiment, the liquid rubber may be a carboxyl or epoxy-terminated acrylonitrile / butadiene copolymer or a derivative thereof. Such liquid rubbers may be available, for example, under the names Hypro / Hypox® CTBN and CTBNX and ETBN from Emerald Performance Materials. Suitable derivatives, particularly elastomer-modified prepolymers with epoxy groups, are available under the Polydis® product line of Struktol® (Schill+Seilacher Gruppe, Germany), especially under the Polydis® 36 product line, or under the Albipox product line (Evonik, Germany).

[0083] In a second embodiment, the liquid rubber may be a polyacrylate liquid rubber that is completely miscible with the liquid epoxy resin and separates only during the curing process of the epoxy resin matrix to form microdroplets. Such a polyacrylate liquid rubber may be obtained, for example, under the name 20208-XPA from Dow.

[0084] Of course, mixtures of liquid rubbers can also be used, especially mixtures of carboxyl-terminated or epoxy-terminated acrylonitrile / butadiene copolymers or their derivatives.

[0085] In a third embodiment, the toughness modifier D may be a core-shell polymer D3. The core-shell polymer consists 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 forms spontaneously due to the separation of block copolymers, or is defined by polymerization as latex polymerization or suspension polymerization followed by grafting. Preferred core-shell polymers are so-called MBS polymers, which are available under the trade name Clearstrength™ from Arkema, Paraaloid™ from Dow, or F-351™ from Zeon.

[0086] Preferably, the toughness modifier D, especially the end-closed polyurethane polymer D1, is 10-30% by weight, particularly 15-25% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0087] Further advantageously, the thermosetting one-component epoxy resin composition further comprises at least one end-blocked polyurethane polymer D1, and the sum of thermoplastic particles TP and end-blocked polyurethane polymer D1 (TP + D1) is 10-45% by weight, preferably 15-40% by weight, more preferably 17.5-35% by weight, based on the total weight of the thermosetting one-component epoxy resin composition. This is advantageous for improved storage stability, such as the increase in viscosity after storage at an elevated temperature of 50°C for one week. This can be seen, for example, in the comparison of E1 and E2 with E3 and E4, or E5 and E6 with E7 and E8 in Table 2.

[0088] It is also preferred that, in this thermosetting one-component epoxy resin composition, the weight ratio (D1 / TP) of the end-blocked polyurethane polymer D1 to the thermoplastic particles TP is 0.4-15, preferably 0.5-7.5, and more preferably 0.8-3. This is advantageous for high impact peel values. This can be seen, for example, in the comparison of E9-E11, E12-E14, and E15-E17 in Table 4. It is further shown in the comparison of E18 with E19 and E20 with E21 in Table 6.

[0089] In a further preferred embodiment, the composition additionally 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, hollow organic beads, glass beads, and colored pigments. Particularly preferred fillers are those selected from calcium carbonate, calcium oxide, and fused silica.

[0090] 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, more preferably 17.5-22.5% by weight.

[0091] In a further preferred embodiment, the composition additionally 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:

[0092] - Monofunctional, saturated or unsaturated, branched or linear, 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.

[0093] - Bifunctional, saturated or unsaturated, branched or linear, 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.

[0094] - Glycidyl ethers of trifunctional or polyfunctional, saturated or unsaturated, branched or linear, cyclic or open-chain alcohols, such as epoxidized castor oil, epoxidized trimethylolpropane, epoxidized pentaerythritol, or aliphatic polyols such as sorbitol, glycerol, polyglycidyl ethers of trimethylolpropane, etc.

[0095] - 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.

[0096] - Epoxidized amines, such as N,N-diglycidylcyclohexylamine, etc.;

[0097] - Epoxidized mono- or dicarboxylic acids, such as glycidyl neodecanoate, glycidyl methacrylate, glycidyl benzoate, diglycidyl phthalate, tetrahydro-diglycidyl phthalate and hexahydro-diglycidyl phthalate, diglycidyl esters of dimer fatty acids, etc.

[0098] - Epoxidized difunctional or trifunctional polyether polyols with low to high molecular weights, such as polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether.

[0099] Hexanediol diglycidyl ether, tolyl glycidyl ether, p-tert-butylphenyl glycidyl ether, polypropylene glycol diglycidyl ether, and polyethylene glycol diglycidyl ether are particularly preferred.

[0100] Advantageously, based on the total weight of the thermosetting one-component epoxy resin composition, the total proportion of the reactive diluent G with epoxy groups is 0.1-15% by weight, preferably 0.1-5% by weight, and particularly preferably 0.1-2.5% by weight.

[0101] The composition may include additional components, particularly catalysts, stabilizers (especially heat and / or light stabilizers), thixotropic agents, plasticizers, solvents, foaming agents, dyes and pigments, corrosion inhibitors, surfactants, defoamers and adhesion promoters.

[0102] Suitable plasticizers, especially alkyl sulfonates or N-butylbenzamides, such as Mesamoll® or Delatol BBS, are available from Bayer.

[0103] Suitable stabilizers, especially substituted phenols such as BHT or Wingstay® T (Elkem), hindered amines, or N-oxygen compounds such as TEMPO (Evonik).

[0104] A particularly preferred one-component epoxy resin composition comprises:

[0105] - Based on the total weight of the thermosetting one-component epoxy resin composition, 10-60% by weight, more preferably 30-60% by weight, and most preferably 40-55% by weight of at least one epoxy resin A having an average of more than one epoxy group per molecule.

[0106] - At least one latent curing agent B for epoxy resin, wherein the latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1, aliphatic dicarboxylic acid dihydrazide B2, and dicyandiamide B3, wherein in the case of B1 or B2, the amount of latent curing agent B for epoxy resin is 2 to 15% by weight, more preferably 6 to 14% by weight, and more particularly 8 to 12% by weight, based on the total weight of the thermosetting one-component epoxy resin composition; in the case of B3, the amount of latent curing agent B for epoxy resin is 0.5 to 12% by weight, more preferably 1 to 8% by weight, and more particularly 2 to 6% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

[0107] - Preferably, at least one accelerator C is selected from substituted ureas, imidazoles, imidazolines, and blocked amines, especially substituted ureas; preferably, when the latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1 and aliphatic dicarboxylic acid dihydrazide B2, the fraction of accelerator C used for the epoxy resin based on the total weight of the thermosetting epoxy resin composition is preferably 0.005-0.5% by weight, more preferably 0.01-0.2% by weight, and most preferably 0.02-0.1% by weight; preferably, when the latent curing agent B is dicyandiamide B3, the fraction of accelerator C used for the epoxy resin based on the total weight of the thermosetting epoxy resin composition is preferably 0.05-2% by weight, more preferably 0.1-1% by weight, and most preferably 0.15-0.5% by weight.

[0108] - At least one toughness modifier D, preferably at least one end-closed polyurethane polymer D1, preferably in an amount of 10-30% by weight, especially 15-25% by weight, based on the total weight of the thermosetting one-component epoxy resin composition;

[0109] - Based on the total weight of the thermosetting one-component epoxy resin composition, preferably 5-30% by weight, more preferably 10-25% by weight, and more preferably 17.5-22.5% by weight of at least one filler F, preferably selected from calcium carbonate, calcium oxide and fumed silica;

[0110] - 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, and especially preferably 0.1-2.5% by weight of the reactive diluent G with epoxy groups.

[0111] Preferably, in a particularly preferred one-component epoxy resin composition, the sum of thermoplastic particles TP and end-blocked polyurethane polymer D1 (TP + D1), based on the total weight of the thermosetting one-component epoxy resin composition, is 10-45% by weight, preferably 15-40% by weight, more preferably 17.5-35% by weight, and / or, preferably and

[0112] The weight ratio (D1 / TP) of the end-closed polyurethane polymer D1 to thermoplastic particles TP is 0.4-15, preferably 0.5-7.5, and more preferably 0.8-3.

[0113] It may also be advantageous that the preferred single-component epoxy resin composition consists of the above-mentioned components to a degree that is greater than 80% by weight, preferably greater than 90% by weight, and especially greater than 95% by weight, based on the total weight of the epoxy resin composition.

[0114] Advantageously, the epoxy resin composition of the present invention has a Pa value of 1000-5500 Pa. s, especially 1000-5000 Pa s, preferably 1000-3000 Pa s, more preferably 1000-2750 Pa The viscosity of s at 25°C was measured, in particular, using a rheometer in oscillating mode with a plate-to-plate geometry, with the following parameters: 5 Hz, measuring gap 1 mm, plate-to-plate diameter 25 mm, and 1% deformation. This is advantageous because it ensures good applyability.

[0115] 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. Such one-component adhesives have a range of possible applications. Such adhesives are required for the bonding of 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. Preferred applications are those where at least one of the materials is a metal. Particularly preferred applications are considered to be the bonding of the same or different metals, especially in body construction in the automotive industry. Preferred metals are particularly steel, especially electrolytically galvanized steel, hot-dip galvanized steel or oiled steel, Bonazinc-coated steel and post-phosphated steel, and aluminum, especially in variants common in automotive construction.

[0116] This method of bonding a thermally stable substrate preferably includes the following stages:

[0117] i) Apply the thermosetting one-component epoxy resin composition as described in detail above to the surface of the thermally stable substrate S1, especially the surface of a metal.

[0118] ii) Contact the applied thermosetting one-component epoxy resin composition with another thermally stable substrate S2, especially the surface of a metal;

[0119] iii) Heating the composition to 100-220°C, especially 120-200°C, preferably between 130 and 150°C, and more preferably between 130 and 140°C.

[0120] The substrate S2 here is composed of the same material as or a different material from the substrate S1. The substrates S1 and / or S2 are in particular the aforementioned metals and plastics.

[0121] Preferably, in step iii), the composition is heated to 100-220°C, especially 120-200°C, preferably between 130 and 150°C, more preferably between 130 and 140°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.

[0122] This method of bonding heat-stabilized materials produces adhesively bonded articles. Such articles are preferably vehicles or parts thereof. Therefore, such adhesively bonded articles can be obtained by the method described above. Furthermore, the compositions according to the invention are suitable not only for automotive construction but also for other applications. Particular mention should be made of their 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).

[0123] Materials bonded by the above-described adhesive composition are preferably used at temperatures generally between 120°C and -40°C, more preferably between 100°C and -40°C, and particularly between 80°C and -40°C.

[0124] A particularly preferred use of this thermosetting one-component epoxy resin composition is as a thermosetting one-component body adhesive in motor vehicle construction, or as a reinforcing compound, or as a foamable thermosetting composition for void reinforcement in structural components and reinforcing elements.

[0125] Another aspect of the invention is the use of the aforementioned thermoplastic particles TP for improving the impact peel strength of a thermosetting one-component epoxy resin composition after curing at 180°C for 40 minutes at 23°C, wherein the impact peel strength is measured as described in the experimental section. The improvement in impact peel strength is compared to the thermosetting one-component epoxy resin composition without the aforementioned thermoplastic particles TP, and wherein the thermosetting one-component epoxy resin composition comprises:

[0126] a) At least one epoxy resin A having an average of more than one epoxy group per molecule, preferably 10-60% by weight, more preferably 30-60% by weight, and most preferably 40-45% by weight, based on the total weight of the thermosetting one-component epoxy resin composition;

[0127] b) At least one latent curing agent B for epoxy resin, preferably, said latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1, aliphatic dicarboxylic acid dihydrazide B2 and dicyandiamide B3;

[0128] c) Preferably, at least one toughness modifier D, and preferably at least one end-closed polyurethane polymer D1.

[0129] Preferably, compared with a thermosetting one-component epoxy resin composition that does not contain thermoplastic particles TP, the improvement in impact peel strength at 23°C is greater than 10%, more preferably greater than 20%, and most preferably greater than 30%.

[0130] Preferably, the thermosetting one-component epoxy resin composition has the following properties:

[0131] Tensile strength as measured in the experimental section, ≥ 25 MPa, especially ≥ 30 MPa, especially ≥ 32.5 MPa;

[0132] The elastic modulus as measured in the experimental section is ≥ 1500 MPa, especially ≥ 1750 MPa, more preferably ≥ 2000 MPa, and most preferably ≥ 2200 MPa.

[0133] Impact peel at 23°C after curing at 150°C for 20 minutes (LB) as measured in the experimental section, with a strength of ≥ 10 N / mm, especially ≥ 20 N / mm, more preferably ≥ 25 N / mm, and most preferably ≥ 30 N / mm.

[0134] Impact peel at 23°C after curing at 180°C for 40 minutes (NB) with a strength of ≥ 10 N / mm, especially ≥ 20 N / mm, more preferably ≥ 25 N / mm, and most preferably ≥ 30 N / mm, as measured in the experimental section. Detailed Implementation

[0135] Example

[0136] The following are some embodiments that further illustrate the invention, but are not intended to limit the scope of the invention in any way.

[0137] Toughness improver (" D1 Preparation of ")

[0138] 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 vacuum dried at 105 °C for 30 min. 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 until the NCO content remained constant at 3.10% after 2.0 hours (calculated NCO content: 3.15%). Subsequently, 96.1 g of cashew nut shell powder was added as a blocking agent. Stirring continued under vacuum at 105 °C until no free NCO could be detected. The product was used as is as a toughness improver. D1 .

[0139]

[0140] Production of the composition

[0141] Reference compositions Ref.1 to Ref.6 and compositions E1 to E21 of the present invention are produced according to the compositions in Table 1, wherein the specified amounts are in parts by weight.

[0142] Test method:

[0143] Tensile strength (TS), elongation at break (EB), and modulus of elasticity (E-modulus) (DIN EN ISO 527)

[0144] The adhesive sample was pressed between two sheets of Teflon paper to a layer thickness of 2 mm. After curing at 180°C for 30 minutes, the Teflon paper was removed, and the sample was die-cut to DIN standard condition. The sample was examined under standard climatic conditions at a strain rate of 2 mm / min. Tensile strength (TS), elongation at break, and modulus of elasticity (0.05–0.25%) were measured at 23°C according to DIN EN ISO 527.

[0145] Impact peel strength (IP) (ISO 11343)

[0146] The specimens were prepared using adhesive and DC04+ZE steel with dimensions of 90 × 20 × 0.8 mm. The bonded area was 20 × 30 mm, the layer thickness was 0.3 mm, and glass beads were used as spacers. The specimens were cured in an oven at 150°C for 20 minutes (LB) or at 180°C for 40 minutes (NB). As a triple determination on a Zwick 450 impact pendulum, the impact peel strength was measured at 23°C (RT) or -30°C (-30°C). The reported impact peel strength is the average force in N / mm² according to the measurement curve from 25% to 90% according to ISO 11343.

[0147] Particle size (D) 50 Determination of surface free energy parameters:

[0148] The average particle size D was determined using a Sympatec HELOS machine and a dry air dispersion (RODOS) method via laser diffraction. 50 The surface free energy and its polar and dispersive components were determined using the Washburn method as described above in the instruction manual.

[0149] Viscosity ( Viscosity at 25°C ）

[0150] One day after fabrication, the viscosity of the adhesive was measured on an Anton Paar MCR 101 rheometer using an oscillating plate-to-plate geometry at 25°C with the following parameters: 5 Hz, measurement gap 1 mm, plate-to-plate diameter 25 mm, and 1% deformation.

[0151] Viscosity / storage stability of the composition (viscosity and increase at 25°C after 7 days / 60°C)

[0152] To assess the storage stability of the adhesive, the viscosity measurement at 25°C was repeated after 7 days of storage at a specified temperature of 60°C (“viscosity after 7d / 60°C”), and the percentage increase in viscosity caused by storage after storage (“increase”) was determined compared to the value before storage (“viscosity at 25°C”).

[0153]

[0154] Table 1, nd = Undetermined

[0155]

[0156] Table 2, nd = not determined

[0157]

[0158] Table 3, nd = Not determined

[0159]

[0160] Table 4, nd = Not determined

[0161]

[0162] Table 5, nd = Not determined

[0163]

[0164] Table 6, nd = Undetermined

Claims

1. A thermosetting one-component epoxy resin composition comprising: a) At least one epoxy resin A having an average of more than one epoxy group per molecule, preferably 10-60% by weight, more preferably 30-60% by weight, and most preferably 40-45% by weight, based on the total weight of the thermosetting one-component epoxy resin composition. b) At least one latent curing agent B for epoxy resin, preferably, said latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1, aliphatic dicarboxylic acid dihydrazide B2 and dicyandiamide B3; c) Preferably at least one toughness modifier D, preferably at least one end-closed polyurethane polymer D1; and d) Thermoplastic particles TP having an average particle size D between 5-400 μm, preferably between 7.5-150 μm, and more preferably between 10-100 μm, as determined by laser diffraction, more preferably by using a Sympatec HELOS machine and dry air dispersion (RODOS). 50 And the polar component of the surface free energy greater than 2 mN / m, determined using the Washburn method as described in the specification.

2. The thermosetting one-component epoxy resin composition according to claim 1, wherein the amount of thermoplastic particles TP is 2.5-30% by weight, preferably 5-22.5% by weight, and more preferably 7.5-15% by weight, based on the total weight of the thermosetting one-component epoxy resin composition.

3. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... The thermoplastic particles TP have a polar component of surface free energy greater than 3 mN / m, preferably greater than 4.5 mN / m, and most preferably greater than 5.5 mN / m, as determined by the Washburn method as described in the specification.

4. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... In the thermoplastic particles TP, the polar component of the surface free energy accounts for more than 10%, preferably more than 15%, and more preferably more than 22.5% of the total surface free energy, wherein the total surface free energy is the sum of the polar component and the dispersive component of the surface free energy, and wherein the surface free energy is determined by the Washburn method as described in the specification.

5. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... The thermoplastic particles TP are polyolefin particles, preferably polyethylene particles.

6. The thermosetting one-component epoxy resin composition according to claim 5, characterized in that... The thermoplastic particles TP are UHMWPE (ultra-high molecular weight polyethylene) particles, preferably having a viscosity-average molecular weight M of 1 million to 11 million g / mol, more preferably 3 million to 10.5 million g / mol, and even more preferably 3 million to 7 million g / mol. v Among them, the viscosity-average molecular weight M v The viscosity was determined using the Margolies equation based on the viscosity value measured according to ISO 1628, Part 3 (Version 2010).

7. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... The thermosetting one-component epoxy resin composition further comprises at least one end-blocked polyurethane polymer D1. Preferably, based on the total weight of the thermosetting one-component epoxy resin composition, the sum of the thermoplastic particles TP and the end-blocked polyurethane polymer D1 (TP+D1) is 10-45% by weight, preferably 15-40% by weight, and more preferably 17.5-35% by weight.

8. The thermosetting one-component epoxy resin composition according to claim 7, characterized in that... The weight ratio (D1 / TP) of the end-closed polyurethane polymer D1 to the thermoplastic particles TP is 0.4-15, preferably 0.5-7.5, and more preferably 0.8-3.

9. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... The latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1 and aliphatic dicarboxylic acid dihydrazide B2, preferably aliphatic dicarboxylic acid dihydrazide B2. Preferably, based on the total weight of the thermosetting one-component epoxy resin composition, the amount of the latent curing agent B for the epoxy resin is 2 to 15% by weight, more preferably 6 to 14% by weight, and more particularly 8 to 12% by weight.

10. The thermosetting one-component epoxy resin composition according to any one of claims 1-8, characterized in that... The latent curing agent B is dicyandiamide B3. Preferably, based on the total weight of the thermosetting one-component epoxy resin composition, the amount of the latent curing agent B for the epoxy resin is 0.5 to 12% by weight, more preferably 1 to 8% by weight, and even more particularly 2 to 6% by weight.

11. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... The thermosetting one-component epoxy resin composition further includes at least one accelerator C for the epoxy resin, selected from substituted ureas, imidazoles, imidazolines, and blocked amines, preferably substituted ureas, more preferably aliphatic substituted ureas; when the latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1 and aliphatic dicarboxylic acid dihydrazide B2, the fraction of the accelerator C for the epoxy resin is preferably 0.005-0.5% by weight, more preferably 0.01-0.2% by weight, and most preferably 0.02-0.1% by weight, based on the total weight of the thermosetting epoxy resin composition; when the latent curing agent B is dicyandiamide B3, the fraction of the accelerator C for the epoxy resin is preferably 0.05-2% by weight, more preferably 0.1-1% by weight, and most preferably 0.15-0.5% by weight, based on the total weight of the thermosetting epoxy resin composition.

12. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... Based on the total weight of the thermosetting one-component epoxy resin composition, the toughness modifier D, especially the end-closed polyurethane polymer D1, accounts for 10-30% by weight, especially 15-25% by weight.

13. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... Based on the total weight of the thermosetting one-component epoxy resin composition, the thermosetting one-component epoxy resin composition further comprises 5-30% by weight, preferably 10-25% by weight, more preferably 17.5-22.5% by weight of at least one filler F, which is preferably selected from calcium carbonate, calcium oxide and fumed silica.

14. The thermosetting one-component epoxy resin composition according to any one of the preceding claims, characterized in that... The thermosetting one-component epoxy resin composition has a Pa content of 1000-5500 Pa. s, especially 1000-5000 Pa s, preferably 1000-3000 Pa s, more preferably 1000-2750 Pa The viscosity of s at 25°C was measured, in particular, using a rheometer in oscillating mode with plate-to-plate geometry, with the following parameters: 5 Hz, measurement gap 1 mm, plate-to-plate diameter 25 mm, and 1% deformation.

15. A method for bonding a heat-stable substrate with an adhesive, comprising the following stages: i) Applying the thermosetting one-component epoxy resin composition according to any one of claims 1 to 14 to a thermally stable substrate S1, especially the surface of a metal; ii) Contact the applied thermosetting one-component epoxy resin composition with another thermally stable substrate S2, especially the surface of a metal; iii) Heating the composition to 100-220°C, especially 120-200°C, preferably between 130 and 150°C, more preferably between 130 and 140°C; The substrate S2 is composed of the same material as or a different material from the substrate S1; preferably in step iii) of heating the composition to a temperature of 100-220°C, especially 120-200°C, preferably between 130 and 150°C, more preferably between 130 and 140°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.

16. Thermoplastic particles (TP) are used to improve the impact peel strength of a thermosetting one-component epoxy resin composition at 23°C after curing at 180°C for 40 minutes, wherein the thermoplastic particles (TP) have an average particle size D between 5-400 μm, preferably between 7.5-150 μm, and more preferably between 10-100 μm, as determined by laser diffraction, more preferably by using a Sympatec HELOS machine and dry air dispersion (RODOS). 50 and the polar component of surface free energy greater than 2 mN / m determined using the Washburn method as described in the specification, wherein the impact peel strength is measured as described in the experimental section, wherein the improvement in impact peel strength is compared with the thermosetting one-component epoxy resin composition without the thermoplastic particles TP, and wherein the thermosetting one-component epoxy resin composition comprises: a) At least one epoxy resin A having an average of more than one epoxy group per molecule, preferably 10-60% by weight, more preferably 30-60% by weight, and most preferably 40-45% by weight, based on the total weight of the thermosetting one-component epoxy resin composition. b) At least one latent curing agent B for epoxy resin, preferably, said latent curing agent B is selected from aromatic dicarboxylic acid dihydrazide B1, aliphatic dicarboxylic acid dihydrazide B2 and dicyandiamide B3; c) Preferably, at least one toughness modifier D, and preferably at least one end-closed polyurethane polymer D1; Preferably, compared with a thermosetting one-component epoxy resin composition that does not contain thermoplastic particles TP, the improvement in impact peel strength at 23°C is greater than 10%, more preferably greater than 20%, and most preferably greater than 30%.

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