Composite material with fast-curing adhesive

Abstract

The present invention relates to a tape for producing a composite material, wherein the tape is coated with an adhesive layer. The adhesive layer has a glass transition temperature ratio from the C-stage to the B-stage of 2.20 ≤ TG_c / TG_B ≤ 5.00. The present invention further relates to a method for producing a composite material using the tape according to the invention, and to the composite material itself.

Description

[0001] ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 1 / 27

[0002] Composite material with fast-curing adhesive

[0003] The present invention relates to a strip or sheet with an applied adhesive layer, a method for producing a composite material using such a strip, and a composite material produced therefrom. The invention lies in the field of materials engineering, in particular the production of multilayer composite materials with structural, acoustic, or functional properties.

[0004] In the following, the terms strip and sheet metal are used synonymously.

[0005] Composite materials that combine tapes with functional structures are widely used in automotive engineering, mechanical engineering, electrical engineering, and the construction industry. It is often necessary to bond different materials together without negatively affecting the properties of the individual components. Particularly when bonding tapes with structured functional layers, for example for acoustic damping or mechanical reinforcement, the selection and application of suitable adhesive systems presents a technical challenge.

[0006] For the purposes of this invention, the terms composite material and composite material are used synonymously.

[0007] For example, international patent application WO 2015 / 022275 Al is known from the prior art. It describes a process for producing a composite material in which a metallic substrate is bonded to a polymeric structure. The bond is achieved via an adhesive layer that is activated by heat. The adhesive systems disclosed therein are based on activated epoxy resins.

[0008] However, it has become apparent that the composite materials must have high temperature stability, stiffness and fatigue strength, and that the sheets with applied adhesive must have high storage stability before bonding.

[0009] The invention is therefore based on the objective of providing a strip with an adhesive coating that is suitable for the production of a composite material, wherein the sheet metal is coated before the process. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 2 / 27

[0010] The material can be stored for extended periods. Furthermore, the task is to provide a composite material that exhibits high temperature stability, high stiffness, and increased strength. The task also includes providing a process for manufacturing the composite material and supplying the composite material itself.

[0011] The problem is solved with a tape for the production of a composite material, wherein the tape is coated on at least one side with an adhesive, the adhesive having a glass transition temperature T G C in the C state relative to the glass transition temperature T G B in B state 2.20 < T G C / T G_B < 5.00, preferably < 4.90 and / or > 2.50, particularly preferably < 4.80 and / or > 2.70, particularly preferably < 4.70 and / or > 3.00, or particularly preferably < 4.50 and / or > 3.50. Surprisingly, it has been found that the ratio of glass transition temperatures in the B-state and C-state according to the invention results in a tape with an adhesive exhibiting excellent storage stability and low adhesion loss. This enables reliable processing of the tape over extended periods and a durable bond with high strength and stiffness in the finished composite material.

[0012] In a particular embodiment, the strip can be a metallic or steel strip with a composition of 0.05% < C < 0.20%; 0.15% < Mn < 4.00%; Si < 1.50%; Nb < 0.060%; Ti < 0.010%. <P < 0,030 %, S < 0,030 % und Rest Fe oder um ein Leichtmetallband mit einer Dichte < 5 g / cm 3, preferably < 4 g / cm³ 3 act.

[0013] In this application, all information regarding the content of the band composition is based on weight, unless expressly stated otherwise. Therefore, all unspecified "%" values ​​relating to a band are to be understood as values ​​in "% by weight".

[0014] The tape can be coated with adhesive either selectively or across its entire surface. Full-surface coatings offer the advantage of simple application of the adhesive layer during a continuous process, as well as maximizing the adhesion strength and stability of the composite material. Selective application is used to allow for the subsequent application of additional functional layers such as coatings or structural elements. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 3 / 27

[0015] The adhesives used are applied to the belt as a liquid adhesive in which the adhesive components are present separately. Before application, the adhesive is in the so-called A state. After application, the adhesive film dries, forming a tack-free film. In this state, the adhesive is in the so-called B state. In the B state, coated belts can be transported, stored, and further processed. To activate the adhesive, a temperature increase is necessary, which leads to melting and activation of the adhesive components. Chemical curing then begins. Once this is complete, the adhesive is in the C state.

[0016] By providing a strip coated with a chemically and / or thermally activatable adhesive, the adhesive-coated strip serves as a precursor for flexibly adaptable manufacturing processes for composite materials. Because the adhesive must first be chemically and / or thermally activated, the bonding action can be performed at a desired time or during a desired process step. Within a short period after activation, the strips must be brought together (optionally preferably under partial or full-surface pressure in the press and / or in a subsequent compaction process) so that they bond together during the chemical curing reaction. Only in this way can flawless, non-delaminated, geometrically accurate, and mechanically stable composite materials be produced.

[0017] Furthermore, the problem is solved using a method for producing a composite material, the method comprising the following steps:

[0018] • a first band according to the invention is provided;

[0019] • a structure, preferably three-dimensional, is provided;

[0020] • the adhesive layer of the first tape is activated;

[0021] • and the first band is bonded to the structure to form a composite material by forming an adhesive bond.

[0022] Preferably, the steps of the procedure are carried out in the order given above.

[0023] The process enables the production of a composite material using a strip that is already coated with an adhesive layer before joining. The adhesive can be ThyssenKrupp Steel Europe AG 257049P10WO 20 February 2026 4 / 27

[0024] The adhesive layer can remain on the tape for extended periods without losing its reactivity, as it is in a storage-stable B-state. This allows for the temporal decoupling of the coating and the joining process, which is particularly advantageous in industrial production lines with variable cycle times. The adhesive layer is activated only immediately before joining, thus enabling a reliable and targeted bond with the structure. The process therefore contributes to increased flexibility, process stability, and cost-effectiveness.

[0025] Furthermore, the problem is solved by a composite material, wherein the composite material comprises at least a first tape according to the invention and a structure, preferably three-dimensional, wherein the tape and the structure are connected to the adhesive layer.

[0026] The composite material according to the invention exhibits high structural integrity because the bond between the tape and the structure is formed by a temperature-stable, durable, and rigid adhesive layer. The use of a tape with a specifically tailored thermal behavior of the adhesive enables a permanent bond even under thermal or mechanical stress. The integration of a structure, particularly a three-dimensional one, allows the targeted adaptation of the composite material's functionality to specific requirements, such as vibration damping, stiffness, or thermal insulation.

[0027] Activation refers to the input of energy to convert components in the adhesive, such as polymer dispersion, hardener, activator, or similar molecules, from an inert to a reactive state and is complete when the reaction to form the final product occurs. This latter reaction occurs through cross-linking of the reactants. In the context of the present invention, "inert" means that the physical and chemical properties of the entire substance remain unchanged, regardless of whether individual reactions take place at the molecular level. The activation temperature refers to the temperature at which a large proportion of the reactants, preferably at least 60%, 65%, 70%, particularly preferably at least 75%, 80%, 85%, 90%, and especially at least 95%, are brought into a reactive state (activation).Activation enables the reactive groups in the adhesive components, such as binders, crosslinkers, hardeners, accelerators, initiators, resins, and other adhesive components, to react and form polymers. This reaction subsequently cures (crosslinks) the adhesive to a degree of cure of at least 60%, 65%, 70%, preferably at least 75%. 80 ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 5 / 27.

[0028] %, particularly preferably at least 85%, 90%, and in particular at least 95%. A degree of curing of 100% is not achievable for steric reasons.

[0029] Prior to activation, the adhesive mixture / coating is inert under the prevailing (room temperature atmospheric) conditions; activation makes the polymers and monomers of the adhesive mixture reactive.

[0030] With the described adhesive properties, the tape has a surface with a potentially short activation time, for example 0.05 to 1 second, preferably 0.3 to 1 second. These properties are accompanied by comparatively high temperature resistance and comparatively high aging resistance.

[0031] The storage stability of the tape is a measure of the pre-reaction of the entire adhesive layer in the B-state during storage and affects the final strength of the adhesive bond in the C-state. Therefore, the storage stability in the bonded state is of crucial importance and impacts the subsequent strength of the composite material. It is measured via the adhesive strength using a tensile shear test according to DIN EN 1465. For this test, samples with an applied adhesive layer in the B-state are stored at 50 °C. The samples are stored at one-week intervals for up to six weeks. After removal from the oven, two samples are bonded together to form a sandwich, in which the adhesive is activated, i.e., converted to the C-state. The tensile shear test according to DIN EN 1465 is then performed on the resulting sandwiches.The adhesive strength after n weeks is compared to the adhesive strength before oven curing (hereinafter referred to as the initial value). If the adhesive strength after n weeks is ≥ 50% of the initial value, preferably ≥ 60%, and particularly preferably ≥ 80%, then the storage stability is (n-1) weeks. In a particular embodiment, the storage stability in the present invention is ≥ 3 weeks, preferably ≥ 4 weeks, and particularly preferably ≥ 5 weeks.

[0032] When the adhesive is heated, both in the B-state and the C-state, softening is observed above a certain temperature. Due to the heating and the resulting softening, segment vibrations occur. The adhesive behaves viscoelastically. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 6 / 27

[0033] The glass transition temperature (glass temperature, glass point) T occurs during the transition from a glassy, ​​harder, more brittle state to the viscoelastic, soft state. G through.

[0034] The glass transition temperature is determined by Dynamic Mechanical Thermal Analysis (DMTA), preferably using the RSA G2 from TA Instruments. First, the adhesive is applied to a tape and dried so that it is in the B-state. Then, a sandwich is formed from two tapes in the B-state at 60 °C for 10 minutes and at a pressure of 3 N / mm². 2 formed. In addition, a sandwich is produced, whereby the sandwich is cooked for 5 minutes at 170 °C and at a pressure of 3 N / mm². 2The two sandwich materials are bonded together so that the adhesive is in the C-state. Rectangular test specimens are then produced from both sandwich types. These are measured using a 3-point bending test over a temperature-dependent curve. First, the composite undergoes conditioning. For this, the samples are measured at 60 °C for 5 minutes with a constant oscillation at 1 Hz and 0.02% deformation, followed by an amplitude test between 0.001% and 1.0% deformation (approximately 5 minutes). The samples are then cooled to 30 °C and a temperature ramp is applied. Finally, a temperature sweep is performed, oscillating from 30 °C to 260 °C at 3 °C / min (sandwich in the B-state) and from 30 °C to 280 °C at 5 °C / min (sandwich in the C-state) at a deformation of 0.02% and 1 Hz. The temperature at which a maximum of the loss factor tan delta (6) is reached is considered, in accordance with the invention, to be the glass transition temperature.The loss factor is calculated from the ratio of loss modulus E" and storage modulus E':.

[0035] "

[0036] <

[0037]

[0038] The adhesive coating applied to the sheet metal preferably consists of an adhesive which, compared to commercially available systems known to those skilled in the art, has a significantly higher glass transition temperature T G C exhibits in the C state. The T G B In the B state, the adhesive is set so that no process-related disadvantages arise during the processing of the sheet metal into the composite material (e.g., paint oozing during the curing process). The adhesive therefore does not soften before activation but remains completely dimensionally stable on the sheet metal until activation. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 7 / 27

[0039] A particularly preferred adhesive is used, wherein the T G C(C state) is at 80 °C to 260 °C, preferably at least 150 °C, preferably at least 200 °C, and particularly preferably at least 230 °C. This has the effect that the adhesive in the composite material cannot potentially soften even when used at higher temperatures.

[0040] In a particular embodiment, the adhesive, preferably in the A state, comprises at least one epoxy resin, at least one, preferably one, latent hardener and at least one, preferably one, latent accelerator.

[0041] In another special embodiment, the adhesive comprises:

[0042] - 60 parts by weight of at least one epoxy resin in solid resin form,

[0043] - 0.5 to 15 parts by weight of at least a latent hardener,

[0044] - 0.5 to 15 parts by weight of at least a latent accelerator.

[0045] The composition given above refers to the mixture of the components present as solids in the specified parts by weight to form an adhesive mixture which, in dispersion and / or solution with a suitable liquid, becomes the adhesive that can form an adhesive coating.

[0046] In its usable state, i.e., in a form suitable for coating, the adhesive with the specified components preferably exists as a dispersion of the composition specified above in a dispersion medium, particularly an aqueous dispersion. This dispersion contains, in one alternative, organic solvents in a proportion of up to 40 wt.%, preferably up to 30 wt.%, particularly preferably up to 20 wt.%, and particularly preferably up to 18 wt.%, based on the aqueous dispersion at 100%. In another alternative, this proportion of organic solvents contains a proportion of 15 wt.%, preferably up to 10 wt.%, particularly preferably up to 7 wt.%, and particularly up to 5 wt.% VOCs (volatile organic compounds). This means that, for example, with a proportion of 40 wt.% organic solvents and a proportion of, for example, 15 wt.% VOCs, the remaining 25 wt.% up to the total proportion of 40 wt.% VOCs are...-% organic solvents are other, non-VOC organic solvents. As an alternative, so-called green solvents are used as non-VOC solvents. These are biodegradable, non-corrosive and non-toxic, i.e. they require ThyssenKrupp Steel Europe AG 257049P10WO 20 February 2026 8 / 27.

[0047] No hazardous substance classification is required, even with boiling points between 190 °C and 230 °C, such as dibasic esters (DBE), particularly the dimethyl esters of dicarboxylic acids (glutaric acid, succinic acid, and adipic acid). The lower limit is set at 0 wt% for VOCs in one alternative, and at 0 wt% for the total organic solvent content in another.

[0048] The use of water as the base of the adhesive mixture in the A-state in one formulation offers both health and safety advantages. The absence of any WOG (Very Volatile Organic Compounds) and the potentially low proportion of other organic solvents and / or VOCs prevent and / or minimize harmful and hazardous flammable emissions.

[0049] The described adhesive preferably contains at least one epoxy resin that has more than one epoxy group and a glass transition temperature in the B state of greater than 50 °C. This has the positive effect that the adhesive behaves very similarly to previously used adhesives during storage and processing, but still exhibits higher reactivity.

[0050] The reactivity of the adhesive layer is measured using NIR activation to determine whether a short energy input is sufficient for subsequent bonding, i.e., crosslinking, particularly partial bonding. For this test, the adhesive is applied to a strip of tape and dried until it is in its B state. The adhesive is then activated using an NIR lamp, and immediately afterward, a paper strip is placed onto the adhesive. Finally, a round 2 kg weight with a contact area of ​​40 mm is used to press the paper strip into the adhesive. 2The paper strip is pressed onto the belt for 30 seconds. During this time, the adhesive cross-links at least partially or completely, and in the case of complete cross-linking, it is in the C-state. After removing the weight, a spring scale is attached to the paper strip and pulled horizontally at a 90° angle to the sample. The force applied until the paper tears is referred to as NIR activation.

[0051] In a preferred embodiment, the at least one epoxy resin can be selected from the group consisting of or containing aliphatic, cycloaliphatic, and aromatic epoxy resins. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 9 / 27

[0052] Aliphatic epoxy resins contain components that bear both an aliphatic group and at least two epoxy resin groups.

[0053] Examples of aliphatic epoxy resins include butanediol diglycidyl ether, hexanediol diglycidyl ether, dimethyl pentane dioxide, butadiene dioxide, and diethylene glycol diglycidyl ether.

[0054] Cycloaliphatic epoxy resins are, for example, 3-cyclohexenylmethyl-3-cyclohexylcarboxylate diepoxide, 3,4-epoxycyclohexylalkyl-3',4'-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-o-methylcyclohexanecarboxylate, Vinylcyclohexane dioxide, bis(3,4-epoxycyclohexyl-methydadipate, dicyclopentadiene dioxide, l,2-epoxy-6-(2,3-epoxypropoxy)hexahydro-4,7-metha-noindane.

[0055] Aromatic epoxy resins include, for example, bisphenol-A epoxy resins, bisphenol-F epoxy resins, phenol-novolac epoxy resins, cresol-novolac epoxy resins, biphenyl epoxy resins, biphenol epoxy resins, 4,4'-biphenyl epoxy resins, divinylbenzene dioxide, 2-glycidylphenyl glycidyl ether, and tetraglycidylmethyl dianilin.

[0056] The connections can be used individually or in combination.

[0057] In a preferred embodiment, the epoxy resin is a mixture of different epoxy resins. In an alternative embodiment, one of these is an epoxy-novolac copolymer. An epoxy-novolac copolymer is a copolymerization product of a novolac and a compound containing epoxy groups, such that the copolymer exhibits epoxy reactivity.

[0058] In a particular embodiment, the adhesive in the A-state contains at least two different epoxy resins or epoxy resin groups. Surprisingly, it has been found that this allows for the maintenance of good NIR activation (reactivity) despite improved storage stability.

[0059] In particular, it has proven advantageous if the at least two different epoxy resins or epoxy resin groups have different glass transition temperatures T. G Bexhibiting. Particularly preferably, two or more different epoxy resins or epoxy resin groups are used, wherein at least one epoxy resin is a copolymer of bisphenol-A epoxy resin. ThyssenKrupp Steel Europe AG 257049P10WO 20 February 2026 10 / 27

[0060] and novolac or a copolymer of bisphenol-A and novolac epoxy resin, in other words a bisphenol-A epoxy-novolac copolymer which has both bisphenol-A segments and novolac segments covalently linked together, in particular a novolac epoxy resin modified with bisphenol-A.

[0061] Alternatively, this copolymer is obtained by reacting epoxidized novolac oligomer with bisphenol-A or by reacting epoxidized bisphenol-A with novolac.

[0062] Preferably, such a copolymer, or its structure, has a novolac backbone (phenolic units linked via CH2 bridges) with embedded bisphenol-A units (iso-propylidene-linked double phenyl structure, i.e., via-C(CH3)2-) and glycidylated phenoxy end groups (-0-CH2-CH-CH2, epoxide ring shown open).

[0063] Alternatively, the polymer can be represented by the following general formula: Ar-CH2-[Ar-CH2]n-Ar (I)

[0064] with Ar = phenyl with defined substituents such as glycidyl and / or bisphenol-A epoxide or bisphenol-A glycidyl ether and n an integer value n = 0-50, preferably n = 0-40, particularly preferably n = 0-30, or n = 0-20, in particular n = 0-10.

[0065] Preferably, the copolymer can be described using the following formula:

[0066] [ Arl-CH2-(Ar2-CH2)n-Ar3 ] (II)

[0067] with:

[0068] Arl, Ar2 and Ar3 each independently represent a phenyl unit, selected from (a) novolac-based phenyl groups, i.e. with phenyl having an OH function or glycidylated O-substituents and

[0069] (b) Bisphenol A units of the general formula

[0070] ArBPA=p-C6H4-C(CH3)2-p-C6H4 (III)

[0071] with C6H4 for phenyl group (Ph) and p for para-;

[0072] n an integer value n = 0-50, preferably n = 0-40, particularly preferably n = 0-30, or n = 0-20, especially n = 0-10; ThyssenKrupp Steel Europe AG 257049P10WO 20 February 2026 11 / 27

[0073] and at least one of the units Arl, Ar2 and Ar3 as a substituent a glycidyloxy or -hydroxypropoxy substituent of the general formula:

[0074] -O-CH2-CH(R)-CH2 (IV)

[0075] where R = 0 (closed epoxide ring) or R = OH (open epoxide precursor from epichlorohydrin reaction).

[0076] The phenyl unit (a) Novolac-based phenyl groups are single phenyl rings connected in the novolac framework via CH2 bridges, where a novolac unit is generally described by the formula HO-Ph-CH2-Ph-CH2-Ph-OH or in glycidylated form (epoxy-O)-Ph-CH2-Ph-CH2-Ph-(O-epoxy).

[0077] The copolymer is characterized by increased crosslinking density, improved thermomechanical stability, and optimized chemical resistance compared to conventional novolac- or bisphenol-A-based epoxy resins. Furthermore, the addition of bisphenol-A leads to the formation of a copolymer with a balanced combination of rigid aromatic segments and flexible bisphenolic structural elements.

[0078] In a preferred embodiment, the composition according to the invention does not include a phenoxy resin. For the purposes of this invention, a phenoxy resin is understood to be a high-molecular-weight, thermoplastic polyhydroxy ether, which is produced, for example, by further polymerization of a diglycidyl ether of a dihydroxyaromatic compound, such as the diglycidyl ether of bisphenol A (DGEBA). Furthermore, phenoxy resins are not only possible based on DGEBA, but also with a novolac core structure, a phenoxy resin with a naphthalene core structure, or a phenoxy resin with a biphenyl core structure. While the epoxy groups are retained in the production of conventional epoxy resins, in the case of the phenoxy resin, the epoxide end groups of the starting compound are completely ring-opened and converted into ether-bound structural units.The resulting polymer therefore no longer has any, or not in a relevant, property-defining number of epoxide functionalities and contains as characteristic functional groups a multitude of secondary hydroxyl groups along the polymer backbone.

[0079] The recurring unit of the phenoxy resin with a bisphenol core structure can be described by the general structural fragment -[O-C6H4-C(CH3)2-C6H4-O-CH2-CH(OH)-CH2]n-. A phenoxy resin is therefore an essentially linear polymer with a mean... ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 12 / 27

[0080] Molar mass (Mw) preferably in the range of at least 20,000 g / mol, particularly preferably at least 30,000 g / mol and particularly at least 50,000 g / mol to 300,000 g / mol.

[0081] Phenoxy resin differs significantly from BPA-diglycidyl ether-based epoxy resins (DGEBA epoxy resins) in several structural and functional aspects. DGEBA resins are low-molecular-weight, prepolymer-like oligomers possessing two terminal epoxy groups. These epoxy groups are retained during manufacturing and serve as crosslinking points for reactive curing systems, particularly amines, anhydrides, or Lewis acid catalysts. In contrast, phenoxy resin is a high-molecular-weight, preferably completely epoxy-free, polyether that is essentially linear and thermoplastic and lacks reactive epoxy groups. Consequently, the curing of an epoxy resin system with DGEBA results in a tightly woven, three-dimensionally crosslinked thermoset network, whereas phenoxy resins are a non-crosslinkable, thermoplastic material with pronounced ductility.

[0082] Furthermore, phenoxy resins differ substantially from novolac epoxy resins. Epoxy novolac resins are obtained by epoxidation of phenolic novolac oligomers and exhibit a large number (>2) of reactive epoxide groups per molecule. This multitude of epoxide functions leads, after curing, to a resin system with a significantly higher functional density and consequently high crosslinking density.

[0083] A further crucial difference lies in the mechanistic behavior during processing and curing. While DGEBA and Novolac epoxy resins, due to their reactive nature, absolutely require hardeners to achieve their final properties, the phenoxy resin, due to its thermoplastic character, can be used as an additive component, adhesion promoter, or binder in coatings, laminating systems, or composite materials without any crosslinking reaction.

[0084] In an alternative, this epoxy resin or epoxy resin group has a mean molar mass of at least 1500 g / mol, preferably at least 1600 g / mol, particularly preferably at least 1700 g / mol, particularly at least 1800 g / mol and a maximum of 2200 g / mol, preferably a maximum of 2100 g / mol, particularly preferably a maximum of 2000 g / mol, and particularly preferably a maximum of 1900 g / mol. In a further alternative, this epoxy resin has a functionality of at least 6, preferably at least 7, particularly preferably at least 7.5 and a maximum of 10, preferably a maximum of 2000 g / mol. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 13 / 27

[0085] 9, particularly preferably a maximum of 8; with an epoxy equivalent weight of at least 200 g / mol, preferably at least 250 g / mol, particularly preferably at least 260 g / mol, particularly at least 270 g / mol and a maximum of 350 g / mol, preferably a maximum of 320 g / mol, particularly preferably a maximum of 300 g / mol, particularly a maximum of 290 g / mol.

[0086] In one version, a bisphenol A epoxy resin is used as the second or further epoxy resin or epoxy resin group.

[0087] In an alternative, the second or further epoxy resin or epoxy resin group has an average molar mass of at least 2500 g / mol, preferably at least 3000 g / mol, particularly preferably at least 3500 g / mol, particularly at least 4000 g / mol and at most 6000 g / mol, preferably at most 5500 g / mol, particularly preferably at most 5000 g / mol, and particularly at most 4500 g / mol. In a further alternative, this epoxy resin has a functionality of at least 1, preferably at least 1.5, particularly preferably at least 1.8 and at most 3, preferably at most 2.5, and particularly preferably at most 2.2. with an epoxy equivalent weight of at least 1200 g / mol, preferably at least 1500 g / mol, particularly preferably at least 1800 g / mol, in particular at least 2000 g / mol and at most 3000 g / mol, preferably at most 2700 g / mol, particularly preferably at most 2500 g / mol, in particular at most 2100 g / mol. The combination of the epoxy resin groups with the different reactivities, i.e.Low and high reactivity in the area according to the invention leads in particular to further improved bearing stability.

[0088] In a particular embodiment, the at least first epoxy resin or epoxy resin group is a novolac copolymer epoxy resin with a functionality of 6 to 10 and the at least second epoxy resin or epoxy resin group is based on bisphenol A with a functionality of 1 to 3.

[0089] In another special embodiment, the at least first epoxy resin or epoxy resin group with functionality 6 to 10 is a copolymer of bisphenol A with novolac epoxy resin.

[0090] An epoxy resin group refers to a mixture of two or more epoxy resins that, within the group, exhibit the functionalities and molar masses mentioned above. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 14 / 27

[0091] In a particular embodiment, exactly two different epoxy resins or two different groups of epoxy resins of the form described above are present. In this embodiment, these are present in a mixing ratio of 4.0:1.0 to 1.0:4.0, preferably 2.0:1.0 to 1.0:2.0, particularly preferably 1.5:1.0 to 1.0:1.5, and especially 1.1:1 to 1:1.1, based on parts by weight in solid resin form. This positively influences the thermal stability of the adhesive in both the B and C states; in particular, the adhesive does not become too soft in the C state up to 200 °C.

[0092] The term latent hardener refers to a substance that serves to harden the epoxy resin, but which must be activated for hardening to occur, particularly through the supply of chemical and / or thermal energy. The latent hardener is added to the adhesive, for example, as a solid in powder form.

[0093] Preferably, a substance or a mixture of substances is used as the latent hardener, which preferably undergoes hardening reactions with the epoxy resins of the adhesive at temperatures in the range of 80 degrees Celsius to 200 degrees Celsius.

[0094] Preferably, the adhesive comprises at least 1, particularly preferably 2, particularly 3 parts by weight up to a maximum of 10, particularly preferably 7, particularly 5 parts by weight of the latent hardener.

[0095] The hardener may contain dicyandiamides, aziridine derivatives, triazine derivatives, imidazolines, imidazoles, o-tolyl biguanide, cyclic amidines, organic hexafluoroantimonate or hexafluorophosphate compounds, or BF3 amine complexes, or any combination of two, three, or more of the aforementioned compounds. In a particular embodiment, the hardener contains only dicyandiamide or consists only of it.

[0096] The connections can be used individually or in combination.

[0097] Examples are 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, l-benzyl-2-methylimidazole, l-benzyl-2-phenylimidazole, l-Cyanoethyl-2-methylimidazole, l-cyanoethyl-2-undecylimida-zole, l-cyanoethyl-2-ethyl-4-methylimidazole, l-cyanoethyl-2-phenylimidazole, l-cyanoethyl-2-un-decylimidazolium trimellitate, l-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-Diamino-6-[2'-me-ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 15 / 27

[0098] thylimidazolyl-(l')]-ethyl-s-triazin, 2,4-Diamino-6-[2'-undecylimidazolyl-(l ')]-ethyl-s-triazin, 2,4-Diamino-6-[2'-ethyl-4'-methylimidazolyl-(l ')]-ethyl-s-2,4-diamino-6-[2"methylimidazolyl-(l')]-ethyl-s-triazin, 2-Phenylimidazol, 2-Phenyl-4,5-dihydroxymethylimidazol, 2-Phenyl-4-methyl-5-hydroxymethylimidazol, 2,3-Dihydro-l H-pyrrolo[l ,2-a]benzimidazol, (l-Dodecyl-2-methyl-3-ben-zyDimidazoliumchlorid, 2-Methylimidazolin, 2-Phenylimidazolin, 2,4-Diamino-6-vinyl-l ,3,5-triazin, 2,4-Diamino-6-vinyl-l,3, 5-triazin Isocyansäure-Addukt, 2,4-Diamino-6-methacryloyloxyethyl-1 ,3,5-triazin, 2, 4-Diamino-6-methacryloyloxyethyl-l, 3, 5-triazin Isocyansäure Addukt, 1 ,3,5-Tria-zin, 2, 4-Diamino-6-methyl-l, 3, 5-triazin, 2, 4-Diamino-6-nonyl-l, 3, 5-triazin, 2,4-Diamino-6-phe-nyl-1 , 3, 5-triazin, 2, 4-Dimethoxy-6-methyl-l, 3, 5-triazin, 2, 4-Dimethoxy-6-phenyl-l, 3, 5-triazin, 2-Amino-4,6-dimethyl-l, 3, 5-triazin, 2-5 Amino-4-dimethylamino-6-methyl-l, 3, 5-triazin, 2-Amino-4-ethoxy-6-methyl-l, 3,5-triazine, 2-amino-4-ethyl-6-methoxy-l, 3, 5-triazine, 2-amino-4-methoxy-6-methyl-l, 3, 5-triazine, 2-amino-4-methyl-6-phenyl-l, 3, 5-triazine, 2-chloro-4,6-dimethoxy-l,3,5-triazine, 2-Ethylamino-4-methoxy-6-methyl-l, 3, 5-triazine, 1-o-tolylbiguanide.,

[0099] In a preferred embodiment, the accelerator contains a urea derivative and / or an imidazole.

[0100] The term latent accelerator refers to a substance that accelerates the curing of the epoxy resin by the latent hardener. The attribute "latent" in the context of the accelerator also indicates that it, too, must first be activated by chemical and / or thermal energy to fulfill its function. The latent accelerator is added to the adhesive, for example, as a solid in powder form.

[0101] In one embodiment, the adhesive can contain 0.5 to 10 parts by weight of a latent accelerator, preferably at least 0.6, particularly preferably 0.7, particularly 0.8 parts by weight up to a maximum of 8, particularly preferably 7, and particularly preferably 5 parts by weight of the latent hardener. In a particularly preferred embodiment, the proportion of the latent accelerator is less than 3 parts by weight. Surprisingly, it has been found that the storage stability can be increased in this case while maintaining the same pencil hardness.

[0102] In one variant of the process, the latent accelerator contains a urea derivative. The advantage of urea derivatives of this type is described in GB 1293142 A. The inventors are ThyssenKrupp Steel Europe AG 257049P10WO, February 20, 2026, 16 / 27.

[0103] found that such derivatives are excellent for the production of composite materials.

[0104] The latent accelerator contained in the adhesive preferably consists of at least 50 wt.%, more preferably at least 90 wt.%, and even more preferably entirely of a urea derivative. The urea derivative preferably used is an N,N-dimethylurea or an N,N'-dimethylurea or a bifunctional urea derivative, particularly preferably with two urea groups as functional groups, in particular a 4,4'-methylene-bis-(phenyldimethylurea), or a mixture of several of the aforementioned.

[0105] The latent accelerator contained in the adhesive preferably consists of at least 50 wt.%, more preferably at least 90 wt.%, more preferably at least 98 wt.%, and especially preferably entirely, of 4,4'-methylene-bis-(phenyldimethylurea).

[0106] In one variant of the procedure, an asymmetrically substituted urea derivative is used, either exclusively or also as the urea derivative.

[0107] In an alternative embodiment of the process, a urea derivative is used in which at least one, preferably two, and particularly preferably three hydrogen atoms are replaced independently by alkyl groups and / or phenyl groups, which may themselves be substituted. The alkyl groups are preferably methyl, ethyl, propyl, or butyl, more preferably methyl; the phenyl group is phenyl or a substituted phenyl, preferably in position 4, also more preferably one of the aforementioned alkyls. In a further alternative, a difunctional urea derivative is defined, according to the invention, as a derivative described above, which has two functional groups. Functional groups are groups of atoms that significantly determine the material properties and, in particular, the reactivity of the compound; in particular, the functional groups undergo reactions.

[0108] Furthermore, the urea derivative to be used is preferably halogen-free. Alternatively, the urea derivative to be used has two urea derivatives as functional groups. Advantageously, this allows epoxy resins to be cured without the presence of dicyanamides as crosslinking agents. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 17 / 27

[0109] A substance can also be a urea derivative.

[0110]

[0111] be provided with R: hydrogen or a group according to

[0112]

[0113] with

[0114] n = 0 or 1, preferably 1,

[0115] X = 0 or S, preferably 0,

[0116] RI, R2 and R3: each hydrogen, a halogen, a nitro group, a substituted or unsubstituted alkyl group, an alkoxyl group, an aryl group or an aryloxyl group,

[0117] R4: Alkyl group, alkenyl group, cycloalkyl group, cycloalkenyl group, aralkyl group optionally substituted by a halogen, hydroxyl or cyanol, preferably methyl, ethyl, propyl, butyl, particularly preferably methyl,

[0118] R5: like R4 or an alkoxyl group, R5 optionally forming a heterocyclic ring with R4, or an N,N-dimethyl-N'-(3,4-dichlorophenyl)urea or an N,N-dimethyl-N'-(3-chloro-4-methylphenyl)urea or an N,N-dimethyl-N'-(3-chloro-4-methoxyphenyl)urea or an N,N-dimethyl-N'-(3-chloro-4-ethylphenyl)urea or an N,N-dimethyl-N'-(4-methyl-3-nitrophenyl)urea or an N-(N'-3,4-dichlorophenylcarbamoyDmorpholine or an N,N-dimethyl-N'(3-chloro-4-methylphenyl)thio-urea; preferably the urea derivative 4,4'-methylene-bis-(phenyldimethylurea); or a Mi-ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 18 / 27

[0119] A mixture of two, three or more of the aforementioned substances. Such a mixture preferably contains at least 10%, 25%, more preferably 50%, 60%, 70%, 80% or 90% 4,4'-methylenebis(phenyldimethylurea).

[0120] The mean particle size (arithmetic mean) of the urea derivative is preferably between 1 micrometer and 30 micrometers.

[0121] In another preferred embodiment, the adhesive further comprises 0.2 to 8 wt.%, preferably 0.2 to 5 wt.%, of an IR absorber. This improves the absorption of thermal radiation, i.e., its activation. The dye can be selected from the group of flame pigments, iron oxide black pigments, or water-soluble dyes, or be a mixture of several of the aforementioned.

[0122] Preferably, the adhesive contains one or more insulating additives known to those skilled in the art, the term "insulating additives" referring to additives specifically provided to increase the electrical resistance of the adhesive. The insulating additives can be present in the adhesive in amounts of 1 to 10 wt.%, preferably 1 to 6 wt.%.

[0123] The adhesive composition may also contain other components, such as a corrosion protection additive.

[0124] Preferably, the adhesive contains one or more fillers known to those skilled in the art, selected from the group consisting of silicates such as clay, loam, talc, mica, kaolin, Neuburg silica; carbonates / sulfates such as chalk, dolomite, barite; and oxides / hydroxides such as quartz flour, crystalline silica, aluminum-magnesium hydroxides, as well as magnesium, zinc, or calcium oxides; or synthetic silicates, oxides, and hydroxides, produced either by precipitation processes (silica, chalk, aluminum and magnesium hydroxide) or in thermal processes (pyrogenic silicon dioxide, carbon black, metal oxides); glass fibers, glass beads, and crushed glass), in amounts of 1 to 20, preferably 1 to 10 wt.%, particularly preferably 1 to 6 wt.%. ThyssenKrupp Steel Europe AG 257049P10WO 20 February 2026 19 / 27

[0125] Preferably, the adhesive contains one or more corrosion inhibitors known to those skilled in the art. The corrosion inhibitors can be present in the adhesive in amounts of 1 to 10 wt.%, preferably 1 to 5 wt.%.

[0126] Alternatively, the dispersion contains defoamers and / or wetting agents.

[0127] In one embodiment, the adhesive according to the invention is free of plasticizers, in particular free of phthalates such as DEHP and / or DBP (diethylhexyl phthalate and dibutyl phthalate) and / or in particular the adhesive according to the invention is free of plasticizers in the so-called B-state on the coated substrate.

[0128] In a preferred embodiment, the adhesive has an adhesive strength > 2 N / mm². 2 , preferably > 4 N / mm 2 , especially preferred > 6 N / mm 2This results in a secure bond in the respective application, particularly for the production of composite materials. The adhesive strength of the adhesive layer is measured using the shear strength test according to DIN EN 1465 at room temperature.

[0129] In a further preferred embodiment, the adhesive in the B state preferably on a strip, particularly preferably on a steel strip, fiber composite material or a light metal strip, exhibits a pencil hardness according to ISO 15184 of > 2 H, preferably > 4 H, particularly preferably > 6 H, and especially preferably > 7 H. Surprisingly, good to consistent pencil hardnesses with improved positional stability can be achieved for the adhesive according to the invention.

[0130] Pencil hardness is determined using a hardness test according to ISO 15184 in the B state. Gliding ability is determined using a 2 kg weight with a contact area of ​​2 cm². 2and determined using a spring scale. The weight is positioned on the adhesive in the B-state and attached to a spring scale with a non-elastic thread parallel to the adhesive surface. The sliding motion is the force required until the weight moves.

[0131] In a further embodiment, the adhesive in the B state preferably exhibits an abrasion resistance according to ISO 9352 of > 20 revolutions, preferably > 25 revolutions, particularly on a steel strip, fiber composites or a light metal strip, on a strip, especially preferably on a steel strip, fiber composites or a light metal strip. ThyssenKrupp Steel Europe AG 257049P10WO 20 February 2026 20 / 27

[0132] The tool is drawn at > 30 revolutions, preferably > 50 revolutions. Improved abrasion, i.e., higher revolution counts, leads to reduced contamination of the die. Reduced contamination of the die minimizes the cleaning effort required. The abrasion of the adhesive in the B-state is determined using an abrasion test according to ISO 9352.

[0133] In one embodiment, the adhesive exhibits a blocking strength in the B-state of 0 or 1, preferably 0. This results in good processability during the die-cutting process.

[0134] Block strength can be considered a measure of pre-bonding and surface reaction in the B-state. This later affects processability during the stamping process. Poor block strength leads to a rough surface on the adhesive side when the coil is unwound. This results in negative effects during the stamping process, including contamination and abrasion in the stamping die. To determine block strength, two sheets with applied adhesive in the B-state are pressed in a press at 1.5 N / mm². 2 The samples were stored at 40 °C for 16 hours. The adhesion between the sheets was then determined using the parameters: no adhesion = 0, partial adhesion = 1, fully bonded = 2.

[0135] The adhesive coating on the tape can be applied to one or both sides. If an adhesive coating is applied to both sides, the coating thickness can be the same, but different thicknesses are also possible.

[0136] The preferred thickness of the adhesive coating, meaning the thickness of the coating on one side for single-sided adhesives and the total thickness of the adhesive coatings on both sides for double-sided adhesives, is between 1 micrometer and 50 micrometers, preferably between 2 micrometers and 20 micrometers. A total thickness between 4 and 8 micrometers is particularly preferred.

[0137] Applying adhesive to one side of the strip results in simpler manufacturing processes, while applying adhesive to both sides of the strip offers the advantage that, for multi-layer composite materials, individual strips can be positioned adhesive-surface to adhesive-surface. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 21 / 27

[0138] This can result in improved adhesion and therefore higher mechanical stability of the composite material.

[0139] Particularly preferred is the first partial coating of the first strip surface and the second partial coating of the second strip surface, with a second thickness, adapted to each other such that the first thickness is at least 1.5 times, preferably 2 times, the second thickness. The thicker first partial coating ensures a reliable and continuous bond with a structure, resulting in high adhesive strength. At the same time, the thinner second partial coating enables controlled adhesive distribution, reduces the risk of adhesive squeeze-out during joining, and contributes to material savings. Overall, this can increase process reliability and improve the mechanical and thermal performance of the resulting composite material.

[0140] Particularly preferred is a double-sided coating with a total thickness of both coatings between 2 and 50 micrometers, preferably between 4 and 20 micrometers. This increases the corrosion protection of the coated material. In a particular embodiment, the layer thickness is 2 to 4 micrometers per side.

[0141] In another alternative, a pretreatment, an adhesion promoter, a phosphating and / or an insulator, for example designed as an insulating varnish layer, is arranged between the tape and the adhesive layer and / or only insulating varnish is arranged on the side of the tape opposite the adhesive layer or it is an uncoated surface.

[0142] The adhesive preferably dries after application at a temperature above room temperature. PMT (peak metal temperature) refers to the temperature of the metal strip surface as determined by a pyrometer. This is the temperature at which the adhesive dries on the surface, i.e., transitions from the A state to the B state. In a particular embodiment, the adhesive is applied at a PMT > 150 °C, preferably > 160 °C, particularly preferably > 170 °C, and especially preferably > 180 °C. Surprisingly, it has been found that at higher PMT, over-application can be reduced. Over-application leads to the release of adhesive during bonding, which can result in contamination and soiling of the material. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 22 / 27

[0143] Squeeze-out is tested using a method known to the expert. This can be done, for example, by applying adhesive to the strip surface with a total adhesive coating thickness of 5 pm on both sides, with a tolerance of 1 pm. The strip surfaces are then subjected to a pressure of, for example, 3 N / mm² in the B-state. 2 The pieces are bonded while being heated from room temperature to 170 °C in 3 minutes. The result is visually assessed. If adhesive oozes out the side during heating, squeezing is performed. If no adhesive oozes out, no squeezing takes place.

[0144] The inventive method produces a composite material, wherein the inventive tape is bonded to a structure, preferably three-dimensional, by forming an adhesive bond. The formation of the adhesive layer is achieved by transitioning the adhesive from the B state to the C state. This transition can be effected by an activation medium, in particular heat (e.g., conductive or inductive) or infrared radiation. In a preferred embodiment, the infrared radiation can be radiation in the NIR wavelength range.

[0145] The structure can preferably be a single layer, as this allows for the formation of a planar contact zone between the structure and the tape, thus enabling a uniform distribution of the adhesive bond. This leads to improved load transfer between the layers of the composite material and increases the mechanical integrity of the connection.

[0146] In a preferred embodiment, the structure has a three-dimensional form, i.e., an extension perpendicular to the strip. Preferably, the structure has a three-dimensional geometry with a thickness greater than the strip thickness, preferably greater than twice the strip thickness, and most preferably three times the strip thickness.

[0147] The structure can consist of solid material (preferably polyethylene or balsa wood), foam (preferably rigid or metal foam), insulating material (preferably rigid foam or mineral wool), or paper, cardboard, metal or plastic, regardless of its dimensional form.

[0148] In a preferred embodiment, the structure exhibits an acoustically damping, electrically insulating, or mechanically reinforcing function. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 23 / 27

[0149] In a preferred embodiment, a second band according to the invention is provided, which is bonded to the structure on the side facing away from the first band by forming an adhesive bond. This creates a sandwich structure, which offers the advantage of a more stable composite material.

[0150] The composite material produced according to the inventive method comprises at least one first inventive band and a structure, preferably three-dimensional, wherein the band and the structure are connected with the adhesive layer.

[0151] The structure can be characterized according to the variants listed in the procedure.

[0152] In a particular embodiment, the composite material comprises at least one second band according to the invention, wherein the band with the structure is connected to the adhesive layer on the side facing away from the first band.

[0153] In a particular embodiment, the composite material exhibits a shear loss of < 70%, preferably < 50%, particularly preferably < 40%, and particularly preferably < 30%, as measured at 200 °C in accordance with DIN EN 1465. The shear loss is derived from the shear values, which in the context of this invention is synonymous with adhesive strength, measured at 200 °C and at room temperature according to DIN EN 1465. The shear loss can then be calculated using the following formula:

[0154] Shear value 200°C

[0155] Loss of liability = 1 — — — ; - Gravity

[0156] In a preferred variant, the composite material is used as a building element for buildings, with the advantage that it is difficult to ignite.

[0157] The invention is explained in more detail below with reference to the following examples, which are not, however, limiting. Five adhesives according to the invention, as shown in Examples 1, 2, 3, 4 and 5 of Table 1, were produced as aqueous dispersions, applied to a belt, and characterized using the corresponding methods as described above. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 24 / 27

[0158] Furthermore, tapes VI and V2 with adhesives not according to the invention were also characterized as comparative examples.

[0159] The strips were bonded together to form composite materials with a strip and a three-dimensional structure.

[0160] The first epoxy resin used was a copolymer of a bisphenol-A epoxy resin and novolac, with a functionality of 8, a mean molar weight of 1840 g / mol, and an epoxy equivalent weight of 280 g / mol, designated as "Copolymer" in the table. The second epoxy resin used was a bisphenol-A epoxy resin with a functionality of 2, a mean molar weight of 4100 g / mol, and an epoxy equivalent weight of 2050 g / mol, designated as BPA. The accelerator used was 4,4'-methylenebis(phenyldimethylurea), designated as 4,4'. Dicyanamide at 3.5 parts by weight was used as the hardener in all experiments.

[0161] In Examples 1 to 3, the two epoxy resins were mixed in a 1:1 ratio based on their weights in solid resin form. The weight percentages of the accelerator and hardener relative to the weight percentages of all epoxy resins can be found in Table 1.

[0162] The adhesive was applied to the tape at the specified PMT according to Table 1.

[0163] Table 2 shows the glass transition temperatures in the B and C states.

[0164] Table 3 shows the measured values ​​for adhesive strength, abrasion, pencil hardness, blocking strength, sliding ability, adhesion loss, and storage stability. hyssenKrupp Steel Europe AG 257049P10WO

[0165] February 20, 2026

[0166] 25 / 27

[0167]

[0168] abelle 1hyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 26 / 27

[0169]

[0170] abelle 2hyssenKrupp Steel Europe AG 257049P10WO

[0171] February 20, 2026

[0172] 27 / 27

[0173]

[0174] Table 3

Claims

ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 1 / 2 Patent claims 1. Strip for the production of a composite material, characterized in that the strip is coated on at least one side with an adhesive, wherein the adhesive has a glass transition temperature T G C in the C state relative to the glass transition temperature T G B in B state 2.20 < T G c / T G _B < 5.

00.

2. Band according to claim 1, characterized in that the adhesive comprises at least one epoxy resin, at least one latent hardener and at least one latent accelerator.

3. Band according to one of the preceding claims, characterized in that the adhesive comprises 60 parts by weight of at least one epoxy resin in solid resin form, 0.5 to 15 parts by weight of at least one latent hardener and 0.5 to 15 parts by weight of at least one latent accelerator.

4. Band according to one of the preceding claims, characterized in that the adhesive contains at least two different epoxy resins or epoxy resin groups.

5. A method for producing a composite material, characterized in that the method comprises the following steps: • a first band according to one of claims 1 to 4 is provided; • a structure, preferably three-dimensional, is provided; • the adhesive layer of the first tape is activated; • and the first band is bonded to the structure to form a composite material by forming an adhesive bond.

6. The method according to claim 5, characterized in that the activation of the adhesive layer is effected by an activation medium, in particular heat or infrared radiation. ThyssenKrupp Steel Europe AG 257049P10WO February 20, 2026 2 / 2 7. Method according to claim 5 or 6, characterized in that a second band according to one of claims 1 to 4 is provided, which is connected to the structure on the side facing away from the first band by forming an adhesive bond.

8. Composite material, characterized in that the composite material comprises at least a first strip according to claims 1 to 4 and a structure, preferably three-dimensional, wherein the strip and the structure are connected to the adhesive layer.

9. Composite material according to claim 8, characterized in that the composite material comprises at least one second band according to claims 1 to 4, wherein the band with the structure is connected to the adhesive layer on the side facing away from the first band.

10. Composite material according to claim 8 or 9, characterized in that the structure has an acoustically damping, electrically insulating or mechanically reinforcing function.

11. Composite material according to one of claims 8 or 10, characterized in that the structure has a three-dimensional geometry with a thickness greater than the strip thickness.

12. Composite material according to one of claims 8 to 11, characterized in that at least one strip consists of a non-grain-oriented electrical steel strip with a thickness of 0.1 mm to 0.5 mm.

13. Composite material according to one of claims 8 to 11, characterized in that at least one strip consists of a light metal or fiber composite material.

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