EP3898757A1

EP3898757A1 - Recoatable heat-curing epoxy resin adhesives

Info

Publication number: EP3898757A1
Application number: EP19818148.9A
Authority: EP
Inventors: Christian Krueger
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2018-12-18
Filing date: 2019-12-17
Publication date: 2021-10-27
Also published as: EP3670565A1; CN113195583A; WO2020127314A1

Abstract

The invention relates to heat-curing epoxy resin compositions which contain an electrically conductive carbon allotrope (KA) selected from the list consisting of conductive blacks (KA-1), graphenes (KA-2), single-walled carbon nanotubes (KA-3) and multi-walled carbon nanotubes (KA-4). Such compositions allow, when uncured and following a cathodic dip coating bath, full coating of the applied composition.

Description

PAINTABLE HEAT-CURING EPOXY RESIN ADHESIVES

Technical field

The present invention relates to the field of thermosetting epoxy resin raw adhesives.

State of the art

Heat-curing epoxy resin adhesives have long been used as adhesives for the shell of transport vehicles.

Typically, the body passes through a KTL (cathodic dip painting) bath at the end of the bodyshell, in which it is coated with a so-called KTL paint, which is then baked in a KTL furnace. Good, full-surface KTL painting is the basis for long-term use of the vehicle, as it makes a significant contribution to corrosion resistance.

However, it has been shown that the applied and not yet

cured raw structural adhesives in the KTL bath are not or only partially coated with the KTL varnish, especially at the edges of the adhesive beads, whose contact surface with the substrate is particularly susceptible to corrosion. This not only results in reduced corrosion resistance but also in aesthetically less demanding surfaces.

Presentation of the invention

It is therefore an object of the present invention to provide heat-curing epoxy resin compositions which, in the uncured state, are sufficiently coated with KTL lacquer after the KTL bath, in particular in the edge region in contact with the substrate. Especially in the uncured state, a complete coating of thermosetting epoxy resin compositions, especially in the edge area in contact with the substrate, with KTL lacquer is particularly demanding.

Surprisingly, it was found that a one-component heat-curing epoxy resin composition according to claim 1 is able to achieve this object. Other aspects include a process for gluing, uses and a glued article.

Preferred embodiments of the invention are the subject of the dependent claims.

Ways of Carrying Out the Invention

In a first aspect, the present invention relates to one-component heat-curing epoxy resin compositions comprising:

- At least one epoxy resin A with an average of more than one epoxy group per molecule;

- At least one hardener B for epoxy resins, which is activated by elevated temperature;

at least one electrically conductive carbon allotrope (KA) selected from the list consisting of conductive carbon blacks (KA-1), graphenes (KA-2), single-walled carbon nanotubes (KA-3) and multi-walled carbon nanotubes (KA-4),

the amount of carbon blacks (KA-1) being 4 to 10% by weight,

the amount of graphenes (KA-2) 4-7% by weight,

the amount of single-wall carbon nanotubes (KA-3) 0.075 - 0.9 wt.

%,

and the amount of multi-walled carbon nanotubes (KA-4) 1.5 - 4 wt .-%, based on the total weight of the one-component thermosetting epoxy resin composition.

The epoxy resin composition contains at least one epoxy resin A with an average of more than one epoxy group per molecule. The epoxy group is preferably in the form of a glycidyl ether group. The epoxy resin A with an average of more than one epoxy group per molecule is preferably an epoxy liquid resin or an epoxy solid resin. The term "solid epoxy resin" is well known to epoxy experts and is used in contrast to "liquid epoxy resins". The glass transition temperature of solid resins is above room temperature, ie they can be broken down into free-flowing particles at room temperature. Preferred solid epoxy resins have the formula (Al)

Here, the substituents R ’and R” independently of one another either represent Fl or CFI3. In this document, the term “independently of one another” in the definition of groups and radicals means in each case that several groups which occur but have the same names in the formulas can each have different meanings.

The index s also stands for a value of> 1.5, in particular from 2 to 12.

Solid epoxy resins of this type are commercially available, for example from Olin or Fluntsman or Flexion.

Compounds of the formula (A-1) with an index s between 1 and 1.5 are referred to by the skilled worker as semisolid epoxy resins. For the present invention, they are also considered solid resins. However, preferred are epoxy resins in the narrower sense, i.e. where the index s has a value of> 1.5.

Preferred liquid epoxy resins have the formula (A-11)

Here, the substituents R ’” and R ”” independently of one another either represent Fl or CFI3. Furthermore, the index r stands for a value from 0 to 1. r preferably stands for a value of less than 0.2.

It is therefore preferably diglycidyl ether of bisphenol-A (DGEBA), of bisphenol-F and of bisphenol-A / F (the name, A / F ' refers here to a mixture of acetone with formaldehyde, which is used as a starting material in its production). Such liquid resins are available, for example, as Araldite® GY 250, Araldite® PY 304, Araldite® GY 282 (Huntsman or Hexion) or DER ™ 331 or DER ™ 330 (Olin) or Epikote 828 (Hexion).

The epoxy resin A preferably represents an epoxy liquid resin of the formula (A-II). In an even more preferred embodiment, the thermosetting epoxy resin composition contains both at least one epoxy liquid resin of the formula (A-II) and at least one solid epoxy resin of the formula (Al).

The proportion of epoxy resin A is preferably 10-85% by weight, in particular 10-60% by weight, preferably 30-50% by weight, of the weight of the composition.

The heat-curing epoxy resin composition contains at least one hardener B for epoxy resins, which is activated by elevated temperature. This is preferably a hardener which is selected from the group consisting of dicyandiamide, guanamines, guanidines, aminoguanidines and their derivatives. Also possible are accelerating hardeners, such as substituted ureas, such as, for example, 3- (3-chloro-4-methylphenyl) -1, 1-dimethylurea (chlorotoluron) or phenyl-dimethylurea, in particular p-chlorophenyl-N, N-dimethylurea (Monuron), 3-phenyl-1, 1-dimethylurea (Fenuron) or 3,4-dichlorophenyl-N, N-dimethylurea (Diuron). Compounds of the class of imidazoles, such as 2-isopropylimidazole or 2-hydroxy-N- (2- (2- (2-hydroxyphenyl) -4,5-dihydroimidazol-1-yl) ethyl) benzamide and amine complexes can also be used .

Hardener B is preferably a hardener which is selected from the group consisting of dicyandiamide, guanamines, guanidines, aminoguanidines and their derivatives; substituted ureas, in particular 3- (3-chloro-4-methylphenyl) -1, 1-dimethylurea (chlorotoluron), or phenyl-dimethylureas, in particular p-chlorophenyl-N, N-dimethylurea (monuron), 3- Phenyl-1, 1-dimethylurea (fenuron), 3,4-dichlorophenyl-N, N-dimethylurea (diuron), and imidazoles and amine complexes.

Dicyandiamide is particularly preferred as hardener B.

The amount of hardener B for epoxy resins, which is activated by elevated temperature, is advantageously 0.1-30% by weight, in particular 0.2-10% by weight, based on the weight of epoxy resin A.

The heat-curing epoxy resin composition contains at least one electrically conductive carbon allotrope (KA) selected from the list consisting of conductive carbon blacks (KA-1), graphenes (KA-2), single-walled carbon nanotubes (KA-3) and multi-walled carbon nanotubes (KA-4).

The amount of carbon blacks (KA-1) is 4-10% by weight, preferably 4-9% by weight, 4-8% by weight, 4-7% by weight, preferably 4-6.5% by weight. %,

the amount of graphenes (KA-2) is 4-7% by weight, preferably 4.5-6.5% by weight,

the amount of single-wall carbon nanotubes (KA-3) is 0.075-0.9% by weight, preferably 0.1-0.8% by weight, 0.1-0.6% by weight, 0.1-0.5% by weight, 0.1-0.4% by weight %, in particular 0.1-0.3% by weight, particularly preferably 0.1-0.25% by weight, most preferably 0.1-0.2% by weight,

and the amount of multi-walled carbon nanotubes (KA-4) is 1.5-4% by weight, preferably 1.5-3% by weight, especially 1.5-2.5% by weight, particularly preferably 1.5-2.25% by weight, most preferably 1.75 - 2% by weight,

based on the total weight of the one-component thermosetting epoxy resin composition.

This is advantageous in that it results in a viscosity at 50 ° C. of <2600 Pa ^* s, 80-2400 Pa ^* s, preferably 150-2000 Pa ^* s, in particular 200-1500 Pa ^* s, particularly preferably 200-1000 Pa ^* s, most preferably 200 - 900 Pa ^* s, can be guaranteed. Compositions with 2600 Pa ^* s or higher viscosity values at 50 ° C are no longer suitable for industrial adhesive application processes. Preferably the Viscosity determined oscillographically by a rheometer with a heated plate (MCR 301, AntonPaar) (gap 1000 miti, measuring plate diameter: 25 mm (plate / plate), deformation 0.01 at 5 Hz, heating rate 10 ° C / min).

The abovementioned quantitative ranges also lead to a flow limit at 25 ° C. of 10-1000 Pa, preferably 30-800 Pa, in particular 30-600 Pa, particularly preferably 30-300 Pa.

The yield point at 25 ° C is preferably determined by a rotary measurement of the shear stress at a viscosity of 500Ό00 Pa ^* s.

The yield point is particularly preferably rotatory using a rheometer with a heatable plate (MCR 301, AntonPaar) at 25 ° C (gap 1000 miti, measuring plate diameter: 25 mm (plate / plate), with a fixed shear rate of 10 s ¹ as shear stress at a viscosity of 500,000 Pa ^* s measured.

Furthermore, the abovementioned quantity ranges ensure an adequate coating with KTL lacquer after the KTL bath in the uncured state. In particular, these compositions achieve a value of> 7 after the KTL coating has been carried out in the example part, which corresponds to a complete overpainting and can be seen, for example, in Tables 4-6. In particular, an uncured and fully coated adhesive bead with a specific volume resistance according to DIN IEC167 / IEC93 / VDE 0303 measured at 23 ° C / 50% rel. Is obtained within this quantity range. Air humidity with a measuring voltage of 10V of <5 ^* 10 ¹⁰ Qxcm, in particular <10 ¹⁰ Qxcm, preferably <10 ⁹ Qxcm, particularly preferably <5 ^* 10 ⁸ Qxcm, <5 ^* 10 ⁸ Qxcm - 5 ^* 10 ⁷ Qxcm.

It is preferably an electrically conductive carbon allotrope (KA) with an electrical conductivity or conductivity in the range from 10 ¹³ to 10 ⁵ S / cm, in particular 10 ¹² to 10 ⁴ S / cm, preferably 10 ¹⁰ to 10 ³ S / cm .

Electrically conductive carbon allotropes (KA), which are particle and / or particle-shaped, are preferred. It is particularly preferred to use conductive carbon allotropes (KA), the individual particles or particles having a shape selected from the list consisting of granular, spherical, Stretched, plate-like, scale-like, cylindrical, conical and frustoconical. Structures of this type can be introduced or incorporated particularly well into the coating composition according to the invention while ensuring high electrical conductivity.

It is preferably an electrically conductive carbon allotrope (KA) with an average particle size D50 in the range from 0.05 nm to 1,000 pm, in particular 0.1 nm to 800 pm, preferably 1 nm to 600 pm, preferably 10 nm to 500 pm.

The conductive carbon allotropes used according to the invention can optionally be functionalized. Such functionalizations are generally known to the person skilled in the art.

The electrically conductive carbon allotrope (KA) can be conductive carbon blacks (KA-1). Guide blacks (KA-1) whose primary particles have an average particle size, in particular an average particle size D50, in the range from 1 nm to 1,000 nm, in particular 10 nm to 800 nm, preferably 50 nm to 500 nm, are advantageous. The size can be determined in particular on the basis of an electron microscopic measurement.

Guide blacks (KA-1) which have a specific surface area (BET surface area, in particular measured according to N2SA) in the range from 10 m ² / g to 2,000 m ² / g, in particular 15 m ² / g to 1,800 m, are further advantageous ² / g, preferably 20 m ² / g to 1,700 m ² / g, preferably 50 m ² / g to 1,600 m ² / g, most preferably 150 m ² / g to 500 m ² / g.

The electrically conductive carbon allotrope (KA) can be graphenes (KA-2), in particular modified graphenes. It can also be single-layer or multi-layer graphene. They are preferably graphenes with a thickness of 5-50 nm, in particular 10-20 nm. The electrically conductive carbon allotrope (KA) can be single-walled carbon nanotubes, also called SWCNTs (KA-3).

It is preferably single-walled carbon nanotubes (KA-3) with an average inner diameter in the range from 0.4 to 50 nm, in particular in the range from 1 to 10 nm, preferably in the range from 1 to 6 nm.

It can also be advantageous if it is single-walled carbon nanotubes (KA-3) with an average length in the range from 0.01 to 1,000 gm, in particular in the range from 0.1 to 500 gm, preferably in the range from 0.5 to 200 gm, particularly preferably in the range from 1 to 100 gm. The size is preferably determined on the basis of an electron microscopic measurement of individual tubes.

The electrically conductive carbon allotrope (KA) can be multi-walled carbon nanotubes, also called MWNTs (KA-4).

The multi-walled carbon nanotubes (MWNTs) are preferably selected from 2- to 30-walled, preferably 3- to 15-walled carbon nanotubes.

It is preferably multi-walled carbon nanotubes (KA-4) with an average inner diameter in the range from 0.4 to 50 nm, in particular in the range from 1 to 10 nm, preferably in the range from 2 to 6 nm.

It can also be advantageous if it is multi-walled carbon nanotubes (KA-4) with an average length in the range from 0.01 to 1,000 pm, in particular in the range from 0.1 to 500 pm, preferably in the range from 0.5 to 200 pm, 1 to 100 pm, particularly preferably in the range from 1 to 5 pm. The size is preferably determined on the basis of an electron microscopic measurement of individual tubes.

It may further be preferred if the thermosetting epoxy resin composition has both graphenes (KA-2) and multi-walled carbon nanotubes (KA-4), the amount of the sum of KA-2 and KA-4 being 2-6% by weight, preferably 2.5 - 5% by weight, in particular 2.5 - 4 % By weight, based on the total weight of the one-component thermosetting epoxy resin composition.

The weight ratio of KA-2 to KA-4 is preferably from 0.33-3, in particular 0.5-2, preferably 0.66-1.5, particularly preferably 0.8-1.2.

This is advantageous in that compositions are obtained which have a low viscosity and a high yield point, which is particularly advantageous for good washout resistance and good application properties.

It is also advantageous if the one-component thermosetting epoxy resin composition is less than less than 5% by weight, less than 2% by weight, less than 1% by weight, less than 0.5% by weight, in particular less than 0.1% by weight. %, most preferably less than 0.01% by weight, of conductive polymers, based on the total weight of the one-component thermosetting epoxy resin composition.

As far as the conductive polymers, which can also be referred to synonymously as electrically self-conducting polymers, these generally represent plastics with electrical conductivity. In particular, they are conductive polymers selected from the group consisting of polyacetylenes, polyanilines, polyparaphenylenes, polystyrenes, Polythiophenes, polyethylene dioxythiophenes (PEDOT), polyethylene dioxythiophenes: polystyrene sulfonates (PEDOT PSS) and polyphenylene vinylenes, in particular polyacetylenes, polyanilines, polyparaphenylenes, polystyrenes and polythiophenes.

It is also advantageous if the one-component thermosetting epoxy resin composition is less than less than 5% by weight, less than 2% by weight, less than 1% by weight, less than 0.5% by weight, in particular less than 0.1% by weight. %, most preferably less than 0.01% by weight, additives selected from the list consisting of carbon fibers, graphite, silicon carbide, metal oxides, metals, in particular iron and zinc, Ammonium salts, fillers containing heavy metals or metals, in particular fillers containing antimony and tin based on titanium dioxide or mica, ionic liquids and ionic and non-ionic surfactants, based on the total weight of the one-component thermosetting epoxy resin composition.

The one-component thermosetting epoxy resin composition preferably contains at least one toughness improver D. The toughness improvers D can be solid or liquid.

In particular, the toughness improver D is selected from the group consisting of terminally blocked polyurethane polymers D1, liquid rubbers D2 and core-shell polymers D3. The toughness improver D is preferably selected from the group consisting of terminally blocked polyurethane polymers D1 and liquid rubbers D2. It is particularly preferably a terminally blocked polyurethane polymer D1.

If the toughness improver D is a terminally blocked polyurethane polymer D1, it is preferably a terminally blocked polyurethane prepolymer of the formula (I).

Here, R ¹ stands for a p-valent radical of a linear or branched polyurethane prepolymer terminated with isocyanate groups after removal of the terminal isocyanate groups and p for a value of 2 to 8.

Furthermore, R ² independently of one another represent a substituent which is selected from the group consisting of and

Here R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent an alkyl or cycloalkyl or aralkyl or arylalkyl group, or R ⁵ together with R ⁶ , or R ⁷ together with R ⁸ forms part of one Form 4- to 7-membered ring, which is optionally substituted.

Furthermore, R ^{9 '} and R ¹⁰ each independently represent an alkyl or aralkyl or arylalkyl group or an alkyloxy or aryloxy or aralkyloxy group and R ^{11 represents} an alkyl group.

R ¹² , R ¹³ and R ¹⁴ each independently represent an alkylene group having 2 to 5 carbon atoms, which may have double bonds or is substituted, or a phenylene group or a hydrogenated phenylene group.

R ¹⁵ , R ¹⁶ and R ¹⁷ each independently represent H or an alkyl group or an aryl group or an aralkyl group and R ¹⁸ represents an aralkyl group or a mono- or polynuclear substituted or unsubstituted aromatic group which may have aromatic hydroxyl groups .

Finally, R ^{4 represents} a residue of an aliphatic, cycloaliphatic, aromatic containing a primary or secondary hydroxyl group or araliphatic epoxide after removal of the hydroxyl and epoxide groups and m for a value of 1, 2 or 3.

Phenols or polyphenols, in particular bisphenols, after removal of a hydroxyl group are to be considered in particular as R ¹⁸ . Preferred examples of such phenols and bisphenols are, in particular, phenol, cresol, resorcinol, pyrocatechol, cardanol (3-pentadecenylphenol (from cashew nutshell oil)), nonylphenol, phenols reacted with styrene or dicyclopentadiene, bisphenol A, bisphenol -F and 2,2'-diallyl-bisphenol-A. On the other hand, R ¹⁸ is to be considered in particular hydroxybenzyl alcohol and benzyl alcohol after removal of a hydroxyl group.

If R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ^{9 '} , R ¹⁰ , R ¹¹ , R ¹⁵ , R ¹⁶ or R ^{17 represents} an alkyl group, this is in particular a linear or branched Ci-C2o- Alkyl group.

If R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ^{9 '} , R ¹⁰ , R ¹⁵ , R ¹⁶ , R ¹⁷ or R ¹⁸ for one

Aralkyl group, this grouping is in particular an aromatic group bonded via methylene, in particular a benzyl group.

If R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ⁹ or R ^{10 represents} an alkylaryl group, this is in particular a Ci to C2o-alkyl group bonded via phenylene, such as, for example, tolyl or xylyl.

The radicals R ² are preferably the substituents of the formulas

E-caprolactam is preferred as the substituent of the formula after removal of the NH proton.

_ _ p ^lo

As a substituent of formula ^ ^p are monophenols or

Polyphenols, especially bisphenols, are preferred after removal of a phenolic hydrogen atom. Particularly preferred examples of such radicals R ² are radicals which are selected from the group consisting of and

The radical Y here is a saturated, aromatic or olefinically unsaturated hydrocarbon radical with 1 to 20 C atoms, in particular with 1 to 15 C atoms. As Y, in particular allyl, methyl, nonyl, dodecyl, phenyl, alkyl ether, carboxylic acid ester or an unsaturated cis-alkyl radical with 1 to 3 double bonds are preferred.

18th

Most preferably R ^{2 is} --- OR

The terminally blocked polyurethane prepolymer of the formula (I) is prepared from the isocyanate group-terminated linear or branched polyurethane prepolymer with one or more isocyanate-reactive compounds R ² H. If more than one such isocyanate-reactive compound is used, the reaction can be carried out sequentially or with a mixture of these connections.

The reaction is preferably carried out in such a way that the one or more isocyanate-reactive compounds R ² H are used stoichiometrically or in a stoichiometric excess to ensure that all NCO groups have been converted.

The polyurethane prepolymer with isocyanate end groups on which R ¹ is based can be made up of at least one diisocyanate or triisocyanate as well produce a polymer QPM with terminal amino, thiol or hydroxyl groups and / or from an optionally substituted polyphenol QPP.

Suitable diisocyanates are aliphatic, cycloaliphatic, aromatic or araliphatic diisocyanates, especially commercially available products such as methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), tolidine diisocyanate (TODI), isophorone diisocyanate (IPDI TM), trimethyl diisocyanate (IPDI TM), trimethyl diisocyanate (IPDI) or 2,6-bis (isocyanatomethyl) bicyclo [2.2.1] heptane, 1,5-naphthalene diisocyanate (NDI), dicyclohexylmethyl diisocyanate (H12MDI), p-phenylene diisocyanate (PPDI), m-tetramethylxylylene diisocyanate (TMXDI ), etc. and their dimers. HDI, IPDI, MDI or TDI are preferred.

Suitable triisocyanates are trimers or biurets of aliphatic, cycloaliphatic, aromatic or araliphatic diisocyanates, in particular the isocyanurates and biurets of the diisocyanates described in the previous paragraph. Suitable mixtures of di- or triisocyanates can of course also be used.

Particularly suitable polymers QPM with terminal amino, thiol or hydroxyl groups are polymers QPM with two or three terminal amino, thiol or hydroxyl groups.

The polymers QPM advantageously have an equivalent weight of 300 -

6000, in particular from 600 to 4000, preferably from 700 to 2200 g / equivalent of NCO-reactive groups.

Preferred polymers QPM are polyols with average molecular weights between 600 and 6000 daltons selected from the group consisting of polyethylene glycols, polypropylene glycols, polyethylene glycol-polypropylene glycol block polymers, polybutylene glycols, hydroxyl-terminated polybutadienes, hydroxyl-terminated butadiene-acrylonitrile copolymers and mixtures thereof.

Particularly preferred polymers QPM are a, w-dihydroxypolyalkylene glycols with C2-C6-alkylene groups or with mixed C2-C6-alkylene groups which are terminated with amino, thiol or, preferably, hydroxyl groups. Polypropylene glycols or polybutylene glycols are particularly preferred. Hydroxyl group-terminated polyoxybutylenes are also particularly preferred. Bis, tris and tetra phenols are particularly suitable as polyphenol QPP. This includes not only pure phenols, but also substituted phenols if necessary. The type of substitution can be very diverse. In particular, this means a substitution directly on the aromatic nucleus to which the phenolic OH group is attached. Phenols are furthermore understood to mean not only mononuclear aromatics, but also multinuclear or condensed aromatics or heteroaromatics which have the phenolic OH group directly on the aromatics or heteroaromatics.

In a preferred embodiment, the polyurethane prepolymer is produced from at least one diisocyanate or triisocyanate and from a polymer QPM with terminal amino, thiol or hydroxyl groups. The polyurethane prepolymer is produced in a manner known to the person skilled in the art of polyurethane, in particular by using the diisocyanate or triisocyanate in a stoichiometric excess with respect to the amino, thiol or hydroxyl groups of the polymer QPM.

The polyurethane prepolymer with isocyanate end groups preferably has an elastic character. It preferably shows a glass transition temperature Tg of less than 0 ° C.

The toughness improver D can be a liquid rubber D2. This can e.g. are a carboxyl- or epoxy-terminated polymer.

In a first embodiment, this liquid rubber can be a carboxyl- or epoxy-terminated acrylonitrile / butadiene copolymer or a derivative thereof. Such liquid rubbers are commercially available, for example, under the names Hypro / Hypox® CTBN and CTBNX and ETBN from Emerald Performance Materials. The derivatives in particular are epoxy-modified elastomer-modified prepolymers, such as those from the Struktol® product line, in particular from the Polydis®, Polycavit®, Polyvertec® product line, from Struktol® (Schill + Seilacher Group, Germany) or from the Albipox product line (Evonik, Germany) are commercially available. In a second embodiment, this liquid rubber can be a polyacrylate liquid rubber which is completely miscible with liquid epoxy resins and does not separate into microdroplets until the epoxy resin matrix has hardened. Such polyacrylate liquid rubbers are available, for example, from Dow under the designation 20208-XPA.

Mixtures of liquid rubbers can of course also be used, in particular mixtures of carboxyl- or epoxy-terminated acrylonitrile / butadiene copolymers or of derivatives thereof.

In a third embodiment, the toughness improver D can be a core-shell polymer D3. Core-shell polymers consist of an elastic core polymer and a rigid shell polymer. Particularly suitable core-shell polymers consist of a core (core) made of elastic acrylate or butadiene polymer, which is enveloped in a rigid shell (shell) made of a rigid thermoplastic polymer. This core-shell structure either forms spontaneously by segregation of a block copolymer or is predetermined by the polymerisation process as a latex or suspension polymerisation with subsequent grafting. Preferred core-shell polymers are so-called MBS polymers, which are commercially available under the trade name KaneAce ™ from Kaneka, Clearstrength ™ from Arkema, Paraloid ™ from Dow or F-351 ™ from Zeon.

The proportion of toughness improver D is preferably from 5-50% by weight, 10-40% by weight, particularly preferably 15-30% by weight, based on the total weight of the epoxy resin composition.

In a further preferred embodiment, the composition additionally contains at least one filler F. These are preferably mica, talc, kaolin, wollastonite, feldspar, syenite, chlorite, bentonite, montmorillonite, calcium carbonate (precipitated or ground), dolomite, quartz, silicas (pyrogenic or precipitated), cristobalite, calcium oxide, aluminum hydroxide, magnesium oxide, ceramic hollow spheres, hollow glass spheres, organic hollow spheres, glass spheres, color pigments. In particular, the filler F is selected from the group consisting of wollastonite, calcium carbonate and pyrogenic silicas. The total proportion of the total filler F is advantageously 5-40% by weight, preferably 10-30% by weight, based on the total weight of the epoxy resin composition.

In a further preferred embodiment, the composition additionally contains at least one epoxy group-carrying reactive diluent G. Such reactive diluents are known to the person skilled in the art. Preferred examples of reactive diluents bearing epoxy groups are:

Glycidyl ethers of monofunctional saturated or unsaturated, branched or unbranched, cyclic or open-chain CA-C30 alcohols, e.g. Butanol glycidyl ether, hexanol glycidyl ether, 2-ethyl hexanol glycidyl ether, allyl glycidyl ether, tetrahydrofurfuryl and furfuryl glycidyl ether, trimethoxysilyl glycidyl ether etc.

- Glycidyl ethers of difunctional saturated or unsaturated, branched or unbranched, cyclic or open-chain C2 - C30 alcohols, e.g. ethylene glycol, butane diol, flexane diol, octane diolyl cidyl ether, cyclohexane dimethanol diolcidyl ether, neopentyl glycol diglycidyl ether etc.

- 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 pentaerythrol or polyglycidyl ether of aliphatic polyols such as sorbitol, glycerol, trimethylolpropane etc.

- Glycidyl ether of phenol and aniline compounds such as phenyl glycidyl ether, cresyl glycidyl ether, p-tert-butylphenyl glycidyl ether, nonylphenol glycidyl ether, 3-n-pentadecenyl glycidyl ether (from cashew nutshell oil), N, N-diglycidyl ether

- Epoxidized amines such as N, N-diglycidylcyclohexylamine etc.

- Epoxidized mono- or dicarboxylic acids such as neodecanoic acid glycidyl ester, methacrylic acid glycidyl ester, benzoic acid glycidyl ester, phthalic acid, tetra- and flexahydrophthalic acid diglycidyl esters, diglycidyl esters of dimeric fatty acids etc. - Epoxidized di- or trifunctional, low to high molecular weight polyether polyols such as polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether etc.

Hexanediol diglycidyl ether, cresyl glycidyl ether, p-te / t-butylphenyl glycidyl ether, polypropylene glycol diglycidyl ether and

Polyethylene glycol diglycidyl ether.

The total proportion of the reactive diluent G carrying epoxy groups is advantageously 0.1-15% by weight, preferably 0.1-5% by weight, particularly preferably 0.1-2% by weight, based on the total weight of the epoxy resin composition.

The composition can comprise further constituents, in particular catalysts, stabilizers, in particular heat and / or light stabilizers, thixotropic agents, plasticizers, solvents, mineral or organic fillers, blowing agents, dyes and pigments, corrosion inhibitors, surfactants, defoamers and adhesion promoters.

Particularly suitable plasticizers are phenol-alkylsulfonic acid esters or benzenesulfonic acid-N-butylamide, as are commercially available from Bayer as Mesamoll® or Dellatol BBS.

Particularly suitable stabilizers are optionally substituted phenols, such as BHT or Wingstay® T (Elikem), sterically hindered amines or N-oxyl compounds, such as TEMPO (Evonik).

A particularly preferred one component

Epoxy resin composition includes:

-10-60% by weight, in particular 30-50% by weight, based on the total weight of the epoxy resin composition, epoxy resin A with an average of more than one epoxy group per molecule; 50-100% by weight, in particular 80-100% by weight, of epoxy resin A is preferably an epoxy liquid resin and 0-30% by weight, in particular 0-20% by weight, particularly preferably 5-15% by weight, of the epoxy resin A is a solid epoxy resin;

at least one latent hardener for epoxy resins B, preferably selected from dicyandiamide, guanamines, guanidines, anhydrides of polybasic carboxylic acids, dihydrazides, and aminoguanidines, and their derivatives, dicyandiamide being preferred;

preferably at least one accelerator C, selected from the list consisting of substituted ureas, imidazoles, imidazolines and blocked amines, in particular selected from the list consisting of substituted ureas and blocked amines, particularly preferably substituted ureas;

at least one toughness improver D is selected from the group consisting of terminally blocked polyurethane polymers D1, liquid rubbers D2 and core-shell polymers D3, the proportion of toughness improver D being preferably 5-50% by weight, 10-40% by weight. %, particularly preferably 15-30% by weight, based on the total weight of the epoxy resin composition;

preferably 5-40% by weight, preferably 10-30% by weight, based on the total weight of the epoxy resin composition, of a filler F preferably selected from the group consisting of wollastonite, calcium carbonate and pyrogenic silicas;

-preferably 0.1-15% by weight, preferably 0.1-5% by weight, particularly preferably 0.1-2% by weight, particularly preferably 0.2-1% by weight, based on the total weight of the epoxy resin composition, of a reactive diluent G bearing epoxy groups;

the amount of carbon blacks (KA-1) being 4-10% by weight, preferably 4-9% by weight, 4-8% by weight, 4-7% by weight, preferably 4-6.5% by weight. -%,

the amount of graphenes (KA-2) 4-7% by weight, preferably 4.5-6.5% by weight,

the amount of single-wall carbon nanotubes (KA-3) 0. 075-0.9% by weight, preferably 0.1-0.8% by weight, 0.1-0.6% by weight, 0.1-0.5% by weight, 0.1-0.4% by weight, in particular 0.1-0.3% by weight, particularly preferably 0.1-0.25% by weight, most preferably 0.1-0.2% by weight,

and the amount of multi-walled carbon nanotubes (KA-4) 1.5-4% by weight, preferably 1.5-3% by weight, in particular 1.5-2.5% by weight, particularly preferably 1.5-2.25% by weight, most preferred 1.75 - 2% by weight, based on the total weight of the one-component thermosetting epoxy resin composition.

It can furthermore be advantageous if the preferred one-component epoxy resin composition comprises more than 80% by weight, preferably more than 90% by weight, in particular more than 95% by weight, particularly preferably more than 98% by weight, most preferably more than 99% % By weight, based on the total weight of the epoxy resin composition, consists of the aforementioned components.

It is particularly preferred to use heat-curing epoxy resin compositions which, in the uncured state:

a viscosity at 50 ° C. of <2600 Pa ^* s, 80-2400 Pa ^* s, preferably 150-2000 Pa ^* s, especially 200-1500 Pa ^* s, particularly preferably 200-1000 Pa ^* s, most preferred 200 - 900 Pa ^* s, in particular determined oscillographically by a rheometer with a heated plate (MCR 301, AntonPaar) (gap 1000 gm, measuring plate diameter: 25 mm (plate / plate), deformation 0.01 at 5 Hz, heating rate 10 ° C / min), and / or

a flow limit of 10-1000 Pa, preferably 30-800 Pa, particularly 30-600 Pa, particularly preferably 30-300 Pa, in particular by means of a rheometer with a heated plate (MCR 301, AntonPaar) at 25 ° C (gap 1000 gm , Measuring plate diameter: 25 mm (plate / plate), measured at a fixed shear rate of 10 s ^_1 as shear stress at a viscosity of 500 000 Pa ^* s, and / or

has a value of> 7 after the KTL coating has been carried out as described in the example section. It is particularly preferred to use heat-curing epoxy resin compositions which, in the cured state:

have a tensile shear strength, in particular measured according to DIN EN 1465, particularly preferably as described in the example section, of more than 10 MPa, more than 15 MPa, more than 20 MPa, and / or

have a tensile strength, in particular measured according to DIN EN ISO 527, particularly preferably as described in the example part, of more than 10 MPa, more than 15 MPa, more than 20 MPa, and / or

have an elongation at break, in particular measured according to DIN EN ISO 527, particularly preferably as described in the example section, of 1 - 30%, 2 - 20%, 3 - 10%, and / or

have a modulus of elasticity, in particular measured according to DIN EN ISO 527, particularly preferably as described in the example section, from 300 to 3500 MPa, from 1000 to 3000 MPa, preferably 1000 to 2000 MPa.

-a specific volume resistance according to DIN IEC167 / IEC93 / VDE 0303 measured at 23 ° C / 50% rel. Humidity with a measuring voltage of 10V of <5 ^* 10 ¹⁰ Qxcm, in particular <10 ¹⁰ Qxcm, preferably <10 ⁹ Qxcm, particularly preferably <5 ^* 10 ⁸ Qxcm, <5 ^* 10 ⁸ Qxcm - 5 ^* 10 ⁷ Qxcm. The volume resistivity is preferably determined as described in the example section.

The cured state is preferably obtained by heating the composition to a temperature of 140-220 ° C., in particular 140-200 ° C., preferably between 160 and 190 ° C., in particular for 10-60 minutes, particularly preferably for 20-45 min.

It has been shown that the heat-curing epoxy resin compositions according to the invention can be used especially as one-component adhesives.

Thus, in a further aspect, the invention relates to a use of the previously described one-component thermosetting epoxy resin composition as a one-component thermosetting adhesive, in particular as a thermosetting one-component structural adhesive in vehicle construction. Such adhesives are required for the bonding of heat-stable materials. Heat-stable materials are understood to be materials which are dimensionally stable at a curing temperature of 140-220 ° C., preferably 140-200 ° C., at least during the curing time. In particular, these are metals and plastics such as ABS, polyamide, polyphenylene ether, composite materials such as SMC, unsaturated polyester GRP, epoxy or acrylate composite materials. The application in which at least one material is a metal is preferred. A particularly preferred use is the bonding of the same or different metals, particularly in the body-in-white in the automotive industry. The preferred metals are primarily steel, in particular electrolytically galvanized, hot-dip galvanized, oiled steel, bonazinc-coated steel, and subsequently phosphated steel, and aluminum, in particular in the variants typically occurring in automobile construction.

Another aspect of the invention thus relates to a method for bonding heat-stable substrates, which have the following steps

i) applying a one-component heat-curing epoxy resin composition, as described above, to the surface of a heat-stable substrate S1, in particular a metal; ii) contacting the applied thermosetting epoxy resin composition with the surface of a further heat-stable substrate S2, in particular a metal;

iii) bringing the substrates S1 and S2 and the thermosetting epoxy resin composition in contact with them into contact with a KTL coating solution, in particular at a temperature between 20 and 80 ° C, in particular between 20 and 50 ° C; preferably between 20 and 40 ° C., in particular for 1-15 min, particularly preferably for 1-5 min;

iv) heating the composition to a temperature of 140-220 ° C, in particular 140-200 ° C, preferably between 160 and 190 ° C, in particular for 10-60 min, particularly preferably for 20-45 min.

The substrate S2 consists of the same or a different material as the substrate S1. In particular, the heat-stable substrate S1 and / or S2 are metals and plastics such as ABS, polyamide, polyphenylene ether, composite materials such as SMC, unsaturated polyester GRP, epoxy or acrylate composite materials. The application in which at least one material is a metal is preferred. A particularly preferred use is the bonding of the same or different metals, particularly in the body-in-white in the automotive industry. The preferred metals are primarily steel, in particular electrolytically galvanized, hot-dip galvanized, oiled steel, bonazinc-coated steel, and subsequently phosphated steel, and aluminum, in particular in the variants typically occurring in automobile construction.

It is therefore preferred that the substrate S1 and / or the substrate S2 is a metal.

Steps i) to iv) are preferably carried out in this order. It is also advantageous if, prior to step iii), no partial or complete, in particular complete, curing of the applied epoxy resin composition takes place, in particular no curing by heating the composition to a temperature of 140-220 ° C., in particular for 10-60 min. particularly preferred for 20 - 45 min.

Step iii) is typically carried out by immersion in a KTL bath containing a KTL painting solution. Preferred coating solutions are described, for example, as cationic electrocoating materials in the Römpp Chemie Lexikon, online version, Georg Thieme Verlag, accessed on December 14, 2018.

Step iv) is typically carried out in a KTL furnace. The composition cures by heating the composition in step iv).

Such a method for gluing heat-stable materials results in a glued article, which is a further aspect of the present invention. Such an article is preferably a vehicle or part of a vehicle, in particular an add-on part of a vehicle.

Furthermore, the invention comprises the use of at least one electrically conductive carbon allotrope (KA) selected from the list consisting of carbon blacks (KA-1), graphenes (KA-2), single-walled carbon nanotubes (KA-3) and multi-walled carbon nanotubes (KA-4), as described above, to reduce the volume resistivity according to DIN IEC167 / IEC93 / VDE 0303 measured at 23 ° C / 50% rel. Air humidity with a measuring voltage of 10V of a hardened one-component thermosetting epoxy resin composition, in particular a hardened thermosetting epoxy resin adhesive, preferably in vehicle construction, in a KTL coating process. It is preferably a thermosetting epoxy resin composition as described above. It is preferably a KTL coating method described above, in particular a KTL coating method as described above, in particular in the example part.

The reduction in volume resistivity relates to the comparison to one-component thermosetting epoxy resin compositions which do not contain any of the electrically conductive carbon allotropes (KA) mentioned above. The volume resistivity is preferably determined as described in the example section.

The reduction is preferably more than 10 ⁴ Qxcm, in particular more than 10 ⁵ Qxcm, preferably more than 10 ⁶ Qxcm.

The type and amount of the electrically conductive carbon allotropes (KA) used is preferably of the type and amount described above, in particular the types and amounts indicated above as preferred are also preferably used.

Examples

Preparation of the compositions

According to the information in Tables 1-6, the

Reference compositions R1-R18 and the compositions E1-E10 according to the invention are produced. With the exception of the composition R2, the amount in% by weight of zinc, basionics, carbon black or KA-1 to KA-4 listed in Table 1 was added for each composition and in return the corresponding amount of filler mixture was removed. For example, 1% by weight of the Tubal Matrix 201 product was used in the composition E1 and only 24.6% by weight of filler mixture was added accordingly.

The composition R2 was prepared according to Table 2.

Table 1, Raw materials used for composition R1, R3 - R18 and

E1 - E10

Table 2, Raw materials used for composition R2

Table 3

Production of the toughness improver LD-1 ")

150 g Poly-THF 2000 (OH number 57 mg / g KOH) and 150 g PolyBD R45V

(OH number 46 mg / g KOH) were dried under vacuum at 105 ° C. for 30 minutes. After the temperature had been reduced 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 was constant at 3.10% after 2.0 h (calculated NCO content: 3.15%). Then 96.1 g of cardanol were added as a blocking agent. Stirring was continued at 105 ° C. under vacuum until no free NCO could be detected. The product was used as a toughener D-1.

Test methods:

Tensile strength (ZF), elongation at break and modulus of elasticity (DIN EN ISO 527)

An adhesive sample was pressed between two Teflon papers to a layer thickness of 2mm. After curing for 35 minutes at 175 ° C., the Teflon papers were removed and the test specimens were punched out in accordance with the DIN standard. The test specimens were measured under a standard climate with a tensile speed of 2 mm / min. The tensile strength (ZF), elongation at break and the modulus of elasticity 0.05-0.25% were determined in accordance with DIN EN ISO 527.

Tensile shear strength (ZSF) (DIN EN 1465)

Test sheets made of steel Elo H420 (thickness 1, 2mm), cleaned and oiled with Anticorit PL 3802-39S, were glued to the adhesive on an adhesive surface of 25 x 10 mm with glass balls as spacers in a layer thickness of 0.3 mm and for 35 min Cured 175 ° C. The tensile shear strength was determined on a tractor at a tensile speed of 10 mm / min in a triple determination in accordance with DIN EN 1465.

KTL coating

The respective was used for coating with a KTL lacquer

Composition at room temperature applied as a round bead (width 15 mm, height 5 mm) to an oiled sheet (200 x 25 mm, electrolytically galvanized, DC-04). The sample was then conditioned in the uncured state for 1 hour at room temperature.

The test specimens were then degreased with an alkaline cleaner prior to KTL coating (Aclean 02.21 cleaning bath from Chemetall, 5 minutes at 60 ° C. Then the test specimen was at 23 ° C. for 20 seconds rinsed under running water. The specimen was then coated.

The KTL bath contained the Cathogard 500 KTL painting solution (from BASF Coatings Münster). The painting time was 5 minutes at a voltage of 280 V and a temperature of the KTL solution of 28 ° C.

After the KTL treatment had been carried out, the caterpillars were cured for 35 min at 175 ° C. and the quality of the caterpillar's KTL coating was assessed on the following scale:

1: Caterpillar not overpainted and gap and edges not filled with KTL coating

2: bead not overpainted, gap and edges partially filled with KTL coating

3: bead not overpainted, gap filled with KTL coating

4: Caterpillar partially overpainted at the edges

5: bead completely overpainted on the gap and edges, 30 - 50% of the surface overpainted

6: bead completely overpainted at gap and edges,> 50% - <100% of the surface overpainted

7: Caterpillar completely overcoated with a thin layer

8: Caterpillar completely overcoated with a medium layer

9: Caterpillar completely overcoated with a thick layer

Samples that had a value of 5 to 9 were described as sufficiently coated.

To measure the conductivity of the adhesives, the mixed compositions were placed between two Teflon foils and brought to a thickness of 1-6 mm using a press, and these adhesive plates were then cured at 175 ° C. for 35 minutes. The specific volume resistance was then in accordance with DIN IEC167 / IEC93 / VDE 0303 at 23 ° C / 50% rel. Air humidity measured at a measuring voltage of 10V on the hardened adhesive plates.

viscosity

The viscosity was measured oscillographically using a rheometer with a heated plate (MCR 301, AntonPaar) at 50 ° C (gap 1000 gm, measuring plate diameter: 25 mm (plate / plate), deformation 0.01 at 5 Hz, heating rate 10 ° C / min). Flow limit

The yield point was rotated using a rheometer with a heated plate (MCR 301, AntonPaar) at 25 ° C (gap 1000 gm, measuring plate diameter: 25 mm (plate / plate), with a fixed shear rate of 10 s ¹ as shear stress with a viscosity measured from 500,000 Pa ^* s.

30/38

Table 4, total SWCNT content, nb not determined, nm not measurable, viscosity too high

31/38

Table 5, ^* = total SWCNT content, nm = not measurable, viscosity too high

Table 6, n.m. = not measurable, viscosity too high

Claims

1. One-component thermosetting epoxy resin composition containing:

the amount of carbon blacks (KA-1) being 4 to 10% by weight,

the amount of graphenes (KA-2) 4-7% by weight,

the amount of single-wall carbon nanotubes (KA-3) 0.075 - 0.9 wt.

%,

2. One-component thermosetting epoxy resin composition according to claim 1, characterized in that

the amount of carbon blacks (KA-1) 4-9% by weight, 4-8% by weight, 4-7% by weight, preferably 4-6.5% by weight,

the amount of graphenes (KA-2) 4.5 - 6.5% by weight,

the amount of single-wall carbon nanotubes (KA-3) 0.1-0.8% by weight, 0.1-0.6% by weight, 0.1-0.5% by weight, 0.1-0.4% by weight, in particular 0.1-0.3% by weight , particularly preferably 0.1-0.25% by weight, most preferably 0.1-0.2% by weight,

and the amount of multi-walled carbon nanotubes (KA-4) 1.5-3

% By weight, in particular 1.5-2.5% by weight, particularly preferably 1.5-2.25

% By weight, most preferably 1.75-2% by weight,

based on the total weight of the one-component thermosetting

Epoxy resin composition.

3. One-component heat-curing epoxy resin composition according to one of the preceding claims, characterized in that the hardener B is selected from the group consisting of dicyandiamide, guanamines, guanidines, aminoguanidines and their derivatives; substituted ureas, especially 3- (3-chloro-4-methylphenyl) -1, 1 -dimethylurea (chlorotoluron), or phenyl-dimethylureas, especially p-chlorophenyl-N, N-dimethylurea (monuron), 3-phenyl-1, 1-dimethyl urea (fenuron), 3,4-dichlorophenyl-N, N-dimethyl urea (diuron), and imidazoles and amine complexes, particularly preferably dicyandiamide.

4. One-component heat-curing epoxy resin composition according to one of the preceding claims, characterized in that it is an electrically conductive carbon allotrope (KA) with an average particle size D50 in the range from 0.05 nm to 1,000 pm, in particular 0.1 nm to 800 pm, preferably 1 nm to 600 pm, preferably 10 nm to 500 pm.

5. One-component heat-curing epoxy resin composition according to one of the preceding claims, characterized in that the conductive carbon black (KA-1) is conductive carbon blacks whose primary particles have an average particle size D50 in the range from 1 nm to 1,000 nm, in particular 10 nm to 800 nm , preferably 50 nm to 500 nm.

6. One-component thermosetting epoxy resin composition according to one of the preceding claims, characterized in that the thermosetting epoxy resin composition has both graphenes (KA-2) and multi-walled carbon nanotubes (KA-4), the amount being the sum of KA-2 and KA-4 2 - 6 wt .-%, preferably 2.5 - 5 wt .-%, in particular 2.5 - 4 wt .-%, based on the total weight of the one-component thermosetting epoxy resin composition.

7. One-component thermosetting epoxy resin composition according to claim 6, characterized in that the weight ratio of KA-2 to KA-4 is 0.33-3, in particular 0.5-2, preferably 0.66-1.5, particularly preferably 0.8-1.2.

8. One-component thermosetting epoxy resin composition according to one of the preceding claims, characterized in that the thermosetting epoxy resin composition has a viscosity at 50 ° C of <2600 Pa ^* s, 80-2400 Pa ^* s, preferably 150-2000 Pa ^* s, in particular 200-1500 Pa ^* s, particularly preferably 200-1000 Pa ^* s, most preferably 200-900 Pa ^* s, has, in particular determined oscillographically by a rheometer with a heated plate (MCR 301, AntonPaar) (gap 1000 miti, measuring plate diameter: 25 mm (plate / plate), deformation 0.01 at 5 Hz, heating rate 10 ° C / min).

9. One-component thermosetting epoxy resin composition according to one of the preceding claims, characterized in that the thermosetting epoxy resin composition has a yield point of 10-1000 Pa, preferably 30-800 Pa, particularly 30-600 Pa, particularly preferably 30-300 Pa, in particular by means of rotation a rheometer with a heated plate (MCR 301, AntonPaar) at 25 ° C (gap 1000 miti, measuring plate diameter: 25 mm (plate / plate), with a fixed shear rate of 10 s ¹ as shear stress at a viscosity of 500,000 Pa ^* s measured.

10. One-component thermosetting epoxy resin composition according to one of the preceding claims, characterized in that the cured one-component thermosetting epoxy resin composition has a volume resistance according to DIN IEC167 / IEC93 / VDE 0303 measured at 23 ° C / 50% rel. Humidity with a measuring voltage of 10V of <5 ^* 10 ¹⁰ Qxcm, in particular <10 ¹⁰ Qxcm, preferably <10 ⁹ Qxcm, particularly preferably <5 ^* 10 ⁸ Qxcm, <5 ^* 10 ⁸ Qxcm - 5 ^* 10 ⁷ Qxcm.

1 1. A method for bonding heat-stable substrates comprising the steps

i) application of a one-component thermosetting epoxy resin composition according to one of claims 1 -10, to the surface of a heat-stable substrate S1, in particular a metal; ii) contacting the applied thermosetting epoxy resin composition with the surface of a further heat-stable substrate S2, in particular a metal;

iv) heating the composition to a temperature of 140-220 ° C., in particular 140-200 ° C., preferably between 160 and 190 ° C., in particular for 10-60 min, particularly preferably for 20-45 min, the substrate S2 consists of the same or a different material as the substrate S1.

12. The method according to claim 1 1, characterized in that before the step iii) there is no complete curing of the applied epoxy resin composition, in particular no curing by heating the composition to a temperature of 140-220 ° C, in particular for 10-60 min. particularly preferred for 20 - 45 min.

13. Use of a one-component thermosetting epoxy resin composition according to one of claims 1 to 10 as a thermosetting one-component structural adhesive in vehicle construction.

14. Glued article, in particular a vehicle or part of a vehicle, which was obtained by a method according to claim 11 or 12.

15. Use of an electrically conductive carbon allotrope (KA) selected from the list consisting of carbon blacks (KA-1), graphenes (KA-2), single-walled carbon nanotubes (KA-3) and multi-walled carbon nanotubes (KA-4), as described in the Composition according to one of claims 1 to 10 is described for reducing the volume resistance according to DIN IEC167 / IEC93 / VDE 0303 measured at 23 ° C / 50% rel. Air humidity with a measuring voltage of 10V of a hardened one-component thermosetting

Epoxy resin composition, in particular a cured thermosetting epoxy resin adhesive, preferably in vehicle construction, in a KTL coating process.