UV-curing reactive adhesive

Description

Technical field of the invention

[0001] The present invention relates to a reactive, preferably pressure-sensitive, adhesive based on acrylic monomers, advantageously in film form, the curing of which is initiated by UV light or visible light, which cures sufficiently slowly so that the joining of the components to be bonded can take place, if necessary, for example, if non-transparent substrates are to be bonded, with a certain time interval after initiation, and which continues to cure even in the dark after bonding. The adhesive comprises (a) at least one reactive monomer or reactive resin, (b) an initiator, in particular a radical initiator, (c) a transition metal complex with ruthenium as the central atom and bipyridine or a singly or polysubstituted bipyridine derivative as a ligand, or iridium as the central atom and phenylpyridine or a singly or polysubstituted phenylpyridine derivative as a ligand, and optionally (d) a polymeric film-forming matrix.Furthermore, a method for producing the reactive adhesive according to the invention, as described above, is provided. The adhesive can be used for bonding various materials, such as plastic, metal, glass, ceramics and / or wood, and achieves high, so-called structural bond strengths. General state of the art

[0002] Two-component adhesive systems based on acrylic monomers have been well-known for years and are extensively described in the technical literature. In these radical-polymerizing systems, a two-component adhesive system is applied to the parts to be bonded, typically using two liquid components. For example, one component consists of the monomers to be polymerized and an activator, while the other component consists of a radical-forming substance (also called a hardener or initiator) and the monomers to be polymerized. After mixing or at least contacting the two components, a chemical reaction between the activator and the radical-forming substance generates at least one radical, and the polymerization reaction of the monomers to be polymerized begins.The radical chain polymerization of the monomer then takes place until chain termination occurs, and the adhesive mass thus hardens, resulting in a permanent bond between the parts to be bonded.

[0003] Two-component adhesive systems based on acrylic monomers are also known in the form of pressure-sensitive films (adhesive tapes). They are described, for example, in EP 300 847 A1, EP 3 010 989 A1, EP 3 063 243 A1, WO 2018 / 104053 A1, and EP 3 328 951 A1. A significant disadvantage of these films is the fact that they consist of two films that must be brought into positive contact, which can be particularly problematic when the surfaces to be bonded are very long and narrow, thus requiring the corresponding adhesive films to be also very long and narrow.

[0004] DE 102 37 000 A1 discloses a process for the production of polyacrylate pressure-sensitive adhesives in which a metal compound (metal atom or metal ion with counterion or ligand) is added to the polyacrylate mass produced by means of sulfur-containing regulators in order to reduce the odor nuisance caused by volatile thiol compounds during thermal processing.

[0005] One-component adhesives based on acrylic monomers are also part of the well-established state of the art. These are typically cured with light, especially UV light. The curing reaction is initiated using a photoinitiator, which decomposes in a photolysis reaction after absorbing (UV) light, forming reactive species that trigger radical polymerization. A disadvantage can be the speed of the curing reaction, particularly when bonding non-transparent substrates. Once the reaction has been initiated, there is usually insufficient time to join the components. Therefore, such adhesives are only suitable for bonding (UV)-transparent substrates, as the irradiation can then pass through the components after they have been joined. Another disadvantage of this type of adhesive is that the polymerization does not continue as a dark reaction.Cationic polymerizing adhesives have advantages in this respect, but here too the polymerization is usually very fast.

[0006] EP 3 390 553 A1 proposes a method in which an adhesive tape consisting of two reacting layers A and B, separated by a barrier layer, is brought to reaction and thus curing using a laser by removing the barrier layer through the action of the laser light. A disadvantage of this method is that a three-layer product structure (layer A / barrier layer / layer B) is necessary.

[0007] EP 3 126 402 B1 discloses a method in which a radical polymerization reaction is triggered by plasma treatment of an adhesive containing a substance reactive with respect to radical polymerization and an additional catalytically active substance. This method achieves a sufficiently slow curing rate. A disadvantage is that a plasma device suitable for achieving good bond strengths is not yet widely available on the market. Furthermore, the achievable bond strength results depend on parameters that are difficult to control in some locations, such as humidity. Object of the present invention

[0008] The present invention is based on the objective of providing an improved, reactive, preferably pressure-sensitive, one-component adhesive based on acrylic monomers, advantageously in the form of films, with which high (so-called structural) bond strengths can be achieved. Curing should be initiated by UV light or visible light. The adhesive should cure sufficiently slowly so that the components to be bonded can be joined after a certain time interval following initiation, thus enabling the bonding of non-transparent components. The adhesive should continue to cure in the dark after initiation and joining of the components. Solution to the task

[0009] This problem is solved by a reactive adhesive comprising (a) at least one reactive monomer or reactive resin, (b) an initiator, in particular a radical initiator, and (c) a transition metal complex with ruthenium or iridium as the central atom, wherein the reactive monomer or reactive resin comprises (a) at least one representative selected from acrylic acid, acrylic esters, methacrylic acid, methacrylic esters, diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, higher functional methacrylates, vinyl compounds and / or oligomeric or polymeric compounds with carbon-carbon double bonds, as well as crosslinking reactive monomers such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, and higher functional methacrylates, and wherein the transition metal complex Ruthenium as the central atom and bipyridine or a simply or multiply substituted bipyridine derivative as ligands, or iridium as the central atom and phenylpyridine or a simply or multiply substituted phenylpyridine derivative as ligands includes.

[0010] It is known that bidentate ligands can be used as ligands in the transition metal complex, particularly those with at least two interconnected heteroaromatic six-membered rings—for example, in the form of a biphenyl—which themselves can be part of a more complex structure, such as polycyclic aromatic hydrocarbons and / or bridged bicyclic or polycyclic aromatic hydrocarbons. When ligands containing biphenyl structural units are used, each of the aromatic rings of the biphenyl can form a "tooth" of the ligand, thus exhibiting bidentate structure. Bicyclic aromatic compounds—such as biphenyl compounds—or polycyclic aromatic compounds can be unsubstituted—that is, they have a hydrogen atom attached to each carbon atom—or they can be singly or polysubstituted.

[0011] The transition metal complex acts as a photoredox catalyst in accordance with the present invention.

[0012] A transition metal complex is known which can be described by the following formula (I) or which at least comprises a structural unit which can be described by the formula (I): where M optionally stands for ruthenium or iridium, N for nitrogen, C for carbon, X1, X2, X3 - hereinafter also referred to as X when the distinction is not important or general statements are made for these building blocks - each optionally and independently stand for nitrogen (N) or carbon (C), Y1a, Y1b, Y2a, Y2b, Y3a, Y3b - hereinafter also referred to as Y when the distinction is not important or general statements are made for these building blocks - each optionally and independently stand for nitrogen (N) or carbon with hydrogen (CH) bonded to it, and where Ar1a, Ar2a, Ar3a (in a circle) each stand for a heteroaromatic six-membered ring (i.e., a heterocyclic aromatic six-membered ring), where the one heteroatom or, if applicable, the two heteroatoms are nitrogen (N) - and the remaining atoms of the ring are accordingly carbon (C), Ar1b,Ar2b and Ar3b (in a circle) can each optionally and independently represent a carbocyclic aromatic six-membered ring or a heterocyclic aromatic six-membered ring, wherein the optionally one or both heteroatoms are nitrogen (N) and the remaining atoms of the ring are accordingly carbon (C), with Ar1a being linked to Ar1b, Ar2a to Ar2b, and Ar3a to Ar3b each being linked via carbon-carbon bonds (CC), resulting in a heterobiphenyl structural element in each case.

[0013] The position and orientation of the atoms (C, N, X (with their respective specifications), Y (with their respective specifications)) in the cycles Ar1a, Ar2a, Ar3a, Ar1b, Ar2b, Ar3b are not fundamentally restricted by the representation chosen above; in particular, the chosen representation initially only means that the atoms specified for the ring are indeed present in it. However, the bicycles comprise the respective unit NCCX (with X as a placeholder for X1, X2, and X3, respectively), in which the respective atoms are adjacent and NC and CX are parts of the respective aromatic (conjugated) ring.Hydrogen can be bonded to the carbon atoms (C) in the cycles Ar1a, Ar2a, Ar3a, Ar1b, Ar2b, Ar3b (not represented by letter symbols) independently of each other, but they can also be substituted, so that both the carbocyclic and the heterocyclic aromatic rings (Ar1a, Ar1b, Ar2a, Ar2b, Ar3a, Ar3b) are optionally and independently unsubstituted, singly substituted or multiply substituted derivatives of the corresponding six-membered rings.

[0014] Possible substituents include, for example, halogenyl groups, alkyl groups, aryl groups, heteroaryl groups, halogenylalkyl groups, halogenylaryl groups, or halogenylheteroaryl groups.

[0015] It is possible that all these substituents were chosen to be hydrogen (H).

[0016] Individual substituents can be halogen atoms, such as fluorine. For example, each of the cycles Ar1a, Ar2a, Ar3a, Ar1b, Ar2b, Ar3b can have two fluorine atoms as substituents.

[0017] Individual substituents can also form bridges to the neighboring ring of the respective biphenyl, resulting in a compound of the general formula (II): where the symbol explanations described for formula (I) apply and furthermore oZ1, oZ2, oZ3 - hereinafter also referred to as oZ when the distinction is not important or when general statements are made for these building blocks - are each optionally present such that at least one of these groups - e.g. oZ1 - or all three groups exist, and independently of each other each represent two adjacent carbon atoms - each bearing a hydrogen or a substituent - and each is part of a conjugated ring, so that oAr1, oAr2, oAr3 (in a circle) each represent - optional, corresponding to the existence of oZ1, oZ2 and oZ3 - aromatic six-membered rings, which together with the respective heterobiphenyl structural element are each condensed to form a tricyclic heteroaromatic structure, wherein the carbon atoms of the groups oZ1, oZ2,oZ3 can optionally and independently bear hydrogen (H) or other substituents – such as hydrocarbon residues or halogen atoms – so that the aromatic rings oAr1, oAr2, oAr3, if present, are each optionally and independently unsubstituted, singly substituted, or doubly substituted derivatives. Both carbon atoms of groups oZ1, oZ2, oZ3 – provided the respective group exists – can each bear a hydrogen atom.

[0018] The statements already made for formula (I) apply to the aromatic cycles and the other substituents of the cycles.

[0019] Within the scope of the present invention, the photoredox catalyst is a transition metal complex with ruthenium as the central atom and bipyridine or a simply or multiply substituted bipyridine derivative as ligands; or a transition metal complex with iridium as the central atom and phenylpyridine or a simply or multiply substituted phenylpyridine derivative as ligands.

[0020] The subject of the dependent claims is further advantageous developments of the reactive adhesive, the method for producing it, and its possible uses. Detailed description of the invention

[0021] The problem described above is solved by means of a reactive adhesive characterized in that it comprises (a) at least one reactive monomer or reactive resin, (b) an initiator, in particular a radical initiator and (c) a transition metal complex with ruthenium or iridium as the central atom as a photoredox catalyst, wherein the reactive monomer or reactive resin (a) comprises at least one representative selected from acrylic acid, acrylic esters, methacrylic acid, methacrylic esters, diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, higher functional methacrylates, vinyl compounds and / or oligomeric or polymeric compounds with carbon-carbon double bonds, as well as crosslinking reactive monomers such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, and higher functional methacrylates, particularly preferably tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-(1,1-dimethylethyl)cyclohexyl methacrylate, 4-acryloylmorpholine, 4-methacryloylmorpholine, 2-Hydroxy-3-phenoxy-propyl acrylate, 2-hydroxy-3-phenoxy-propyl methacrylate, (5-ethyl-1,3-dioxan-5-yl)methyl acrylate, Bisphenol A glycerolate dimethacrylate (BIS-GMA),Bisphenol A dimethacrylate (BIS-DMA) and the crosslinking reactive monomers ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethyloylpropane propoxylate triacrylate, trimethyloylpropane triacrylate and / or di(trimethylolpropane) tetraacrylate, wherein the transition metal complex comprises ruthenium as the central atom and bipyridine or a singly or polysubstituted bipyridine derivative as a ligand, or iridium as the central atom and phenylpyridine or a singly or polysubstituted phenylpyridine derivative as a ligand.

[0022] In a preferred embodiment of the invention, a reactive adhesive is provided comprising (a) at least one reactive monomer or reactive resin, (b) an initiator, in particular a radical initiator, (c) a transition metal complex with ruthenium or iridium as the central atom as a photoredox catalyst, and (d) a polymeric film-forming matrix, wherein the reactive monomer or reactive resin comprises (a) at least one representative selected from acrylic acid, acrylic esters, methacrylic acid, methacrylic esters, diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, higher functional methacrylates, vinyl compounds, and / or oligomeric or polymeric compounds with carbon-carbon double bonds, as well as crosslinking reactive monomers such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, and higher functional methacrylates, particularly preferably tetrahydrofurfuryl acrylate.tetrahydrofurfuryl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-(1,1-dimethylethyl)cyclohexyl methacrylate, 4-acryloylmorpholine, 4-methacryloylmorpholine, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl methacrylate, (5-ethyl-1,3-dioxan-5-yl)methyl acrylate, bisphenol A glycerolate dimethacrylate (BIS-GMA), bisphenol A dimethacrylate (BIS-DMA) and the crosslinking reactive monomers ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethyloylpropane propoxylate triacrylate, trimethyloylpropane triacrylate and / or di(trimethylolpropane) tetraacrylate, wherein the Transition metal complex, comprises ruthenium as the central atom and bipyridine or a simply or multiply substituted bipyridine derivative as ligands, or iridium as the central atom and phenylpyridine or a simply or multiply substituted phenylpyridine derivative as ligands.

[0023] In a further preferred embodiment, a reactive adhesive according to the invention is provided which is adhesive.

[0024] In a further preferred embodiment, a reactive adhesive according to the invention is provided in the form of a film.

[0025] In a further preferred embodiment, a reactive adhesive according to the invention is provided in film form, comprising further films, layers, adhesives, carriers, release papers and / or release liners.

[0026] In a further preferred embodiment, a method for producing a reactive adhesive according to the invention is disclosed, wherein the method, excluding UV light or visible light of the wavelength by which the respective photoredox catalyst - i.e. the transition metal complex - is excited, comprises the following steps: 1. Dissolving and / or finely dispersing the ingredients in one or more solvents and / or water, 2. Mixing the dissolved or finely dispersed ingredients, 3. Coating a release liner or paper, a backing material or pressure-sensitive adhesive, or the substrate to be bonded with the mixture of dissolved or finely dispersed ingredients according to step 2, 4. Evaporating the solvent and / or water. wherein the ingredients (a) at least one reactive monomer or reactive resin, (b) an initiator, in particular a radical initiator, (c) a Transition metal complex comprising ruthenium or iridium as the central atom serving as a photoredox catalyst, optionally (d) a polymeric film-forming matrix and optionally further additives and / or auxiliary materials.

[0027] Steps 1 and 2 can also be carried out in one step, meaning the ingredients can be dissolved and / or finely dispersed and mixed simultaneously.

[0028] In a further preferred embodiment, a method for producing a reactive adhesive film according to the invention is disclosed, wherein the method, excluding UV light or visible light of the wavelength by which the respective photoredox catalyst - i.e. the transition metal complex - is excited, comprises the following steps: 1. Dissolving and / or finely dispersing the ingredients in one or more solvents and / or water, 2. Mixing the dissolved or finely dispersed ingredients, 3. Coating a release liner or paper, a backing material, or an adhesive film with the mixture of dissolved or finely dispersed ingredients according to step 2, 4. Evaporating the solvent and / or water, and 5. If necessary, winding the reactive adhesive film into a roll. wherein the ingredients (a) at least one reactive monomer or reactive resin, (b) an initiator, in particular a radical initiator, (c) a Transition metal complex comprising (d) a polymeric film-forming matrix and optionally further additives and / or auxiliary materials, with ruthenium or iridium as the central atom serving as a photoredox catalyst.

[0029] Steps 1 and 2 can also be carried out in one step, meaning the ingredients can be dissolved and / or finely dispersed and mixed simultaneously.

[0030] In a further embodiment according to the invention, a composite body is disclosed which is joined by the reactive adhesive or adhesive film according to one of the preceding claims.

[0031] The components of the adhesive or adhesive film according to the invention are described in detail below. Reactive monomer or reactive resin

[0032] As used herein, the reactive monomer or reactive resin shall stand for a monomer or resin that is particularly capable of radical chain polymerization.

[0033] According to the invention, the reactive monomer is selected from at least one representative selected from acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, vinyl compounds and / or oligomeric or polymeric compounds with carbon-carbon double bonds, as well as crosslinking reactive monomers such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, and higher functional methacrylates.

[0034] Particularly preferred monomers are tetrahydrofurfuryl acrylate (CAS No.: 2399-48-6), tetrahydrofurfuryl methacrylate (CAS No.: 2455-24-5), 2-phenoxyethyl acrylate (CAS No.: 48145-04-6), 2-phenoxyethyl methacrylate (CAS No.: 10595-06-9), 3,3,5-trimethylcyclohexyl methacrylate (CAS No.: 7779-31-9), 4-(1,1-dimethylethyl)cyclohexyl methacrylate (CAS No.: 46729-07-1), 4-acryloylmorpholine (CAS No.: 5117-12-4), 4-methacryloylmorpholine (CAS No.: 5117-13-5). 2-Hydroxy-3-phenoxypropyl acrylate (CAS No.: 16969-10-1), 2-Hydroxy-3-phenoxypropyl methacrylate (CAS No.: 16926-87-7), (5-Ethyl-1,3-dioxan-5-yl)methyl acrylate (CAS No.: 66492-51-1; available from Sartomer-Arkema under the trade name SR531), N-vinyl caprolactam (CAS No.: 2235-00-9), bisphenol A glycerol dimethacrylate (BIS-GMA, CAS No.: 1565-94-2), bisphenol A dimethacrylate (BIS-DMA, CAS No.: 3253-39-2), and the crosslinking reactive monomers ethylene glycol diacrylate (CAS No.: 2274-11-5), Ethylene Glycol Dimethacrylate (CAS No.: 97-90-5), Trimethyloylpropanepropoxylate triacrylate (CAS No.: 53879-54-2), Trimethyloylpropane triacrylate (CAS No.: 15625-89-5) and / or Di(trimethylolpropane)tetraacrylate (CAS No.: 94108-97-1).

[0035] According to the invention, the amount of the reactive monomer(s) or reactive resin(s) is in the range of approximately 10 to 90 wt.%, preferably approximately 40 to 70 wt.%, based on the total mixture of the components of the reactive adhesive according to the invention. Most preferably, approximately 45 to 65 wt.% of the reactive monomer(s) or reactive resin(s) is used, based on the total mixture of the components of the reactive adhesive. The total mixture of the components of the reactive adhesive according to the invention refers here to the total amount of the (a) reactive monomers / reactive resins, (b) the initiator, (c) the photoredox catalyst, (d) optionally the polymeric film-forming matrix, and optionally other components, which is obtained as a sum in wt.%.Solvents or water are used only for the production process and are not included in the overall mixture of the components of the reactive adhesive according to the invention in this consideration. Initiator, especially radical initiator

[0036] As used herein, the term initiator, in particular radical initiator or radical-forming substance, refers to a compound that can initiate a polymerization reaction or crosslinking polymerization reaction of the adhesive. However, the initiator, especially the radical initiator, participates in the reaction only to a very small extent and consequently does not constitute a polymer component that determines the properties of the bond.

[0037] In the present invention, an initiator, in particular a radical initiator, is added to the reactive adhesive according to the invention.

[0038] Radical initiators are preferred. All radical initiators known in the prior art can be used. Preferred radical initiators are peroxides, in particular hydroperoxides.

[0039] In a particularly preferred embodiment according to the invention, the radical initiator is an organic peroxide. Hydroperoxides are particularly preferred, especially diisopropylbenzene hydroperoxide (CAS No. 26762-93-6). Diisopropylbenzene hydroperoxide is preferably used in the form of a 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, available under the trade name Peroxan® IHP-50 from Pergan GmbH, Bocholt, Germany. α,α-Dimethylbenzyl hydroperoxide, also known as cumene hydroperoxide (CAS No. 80-15-9), can also be used. Furthermore, for example, p-menthane hydroperoxide (CAS No. 26762-92-5), tert-amyl hydroperoxide (CAS No. 3425-61-4) or 1,1,3,3-tetramethylbutyl hydroperoxide (CAS No. 5809-08-5) can also be used.

[0040] According to the invention, the amount of radical initiator is in the range of approximately 0.1 to 10 wt.%, preferably approximately 0.2 to 8 wt.%, based on the total mixture of the components of the reactive adhesive according to the invention. Most preferably, approximately 0.5 to 6 wt.% radical initiator is used, based on the total mixture of the components of the reactive adhesive according to the invention. The total mixture of the components of the reactive adhesive according to the invention refers here to the total amount of the (a) reactive monomers / reactive resins, (b) the initiator, (c) the photoredox catalyst, (d) optionally the polymeric film-forming matrix, and optionally other components, which is obtained as a sum in wt.%. Solvents or water are used only for the preparation and are not included in the total mixture of the components of the reactive adhesive according to the invention in this consideration. Photoredox catalyst

[0041] As used here, the term photoredox catalyst refers to a (UV) light-sensitive compound that, when excited by (UV) light, can mediate the transfer of electrons between chemical compounds that would otherwise react more slowly or not at all. Unlike a photoinitiator, a photoredox catalyst does not decompose into reactive fission products when irradiated with (UV) light, but is merely brought into an excited state, which is generally relatively long-lived and from which redox processes can be initiated or mediated.

[0042] In general, suitable photoredox catalysts for activating a radically polymerizable system are those described above according to the general formulas (I) or (II).

[0043] In the embodiment according to the invention, the photoredox catalyst is a transition metal complex with ruthenium as the central atom and bipyridine or a simply or multiply substituted bipyridine derivative as ligands, or a transition metal complex with iridium as the central atom and phenylpyridine or a simply or multiply substituted phenylpyridine derivative as ligands.

[0044] In a preferred embodiment of the invention, the photoredox catalyst is selected from: i. [Tris(2,2'-bipyridyl)ruthenium(II)] 2+< , [Ru(bpy) 3 ] 2+< - Formula (la): ii. Tris[2-(2,4-difluorophenyl)pyridine]iridium(III), Ir(Fppy) 3 ; CAS No.: 387859-70-3 - Formula (Ib): iii. Tris(2-phenylpyridinato)iridium(III), Ir(ppy) 3 ; CAS No.: 94928-86-6 - Formula (Ic):

[0045] The preferred counterion of the cation of formula (1a) is chloride. The corresponding commercially available product contains water of crystallization. The particularly preferred embodiment of the photoredox catalyst of formula (1a) is therefore Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate, (CAS No.: 50525-27-4), available from CHEMOS GmbH & Co. KG (http: / / www.chemos.de), as are the photoredox catalysts of formula (1c).

[0046] The photoredox catalyst with formula (Ib) is available from Strem Chemicals, Inc. (http: / / www.strem.com).

[0047] Examples of photoredox catalysts of formulas (I) or (II) that are advantageously suitable according to the invention are further mentioned as tris-(2,2'-bipyrimidine)ruthenium 2+< (Ru(bpm) 3 2+< ); tris-(2,2'-bipyrazine)ruthenium 2+< (Ru(bpz) 3 2+< ); tris-(1,10-phenanthroline)ruthenium 2+< (Ru(phen) 3 2+< ); bis-(2-(2',4'-difluorophenyl)-5-trifluoromethylpyridine)(ditert-butylbipyridine) iridium +< (Ir(dF(CF 3 )ppy) 2 (dtbbpy) +< ); bis-(2-phenylpyridine)(ditert-butylbipyridine)iridium +< (Ir(ppy) 2 (dtbbpy) +< ).

[0048] According to the invention, the amount of photoredox catalyst is in the range of up to approximately 5 wt.%, preferably 0.05 to 2.0 wt.%, based on the total mixture of the components of the reactive adhesive according to the invention. Most preferred is approximately 0.1–1.0 wt.% photoredox catalyst, based on the total mixture of the components of the reactive adhesive according to the invention. The total mixture of the components of the reactive adhesive according to the invention refers here to the total amount of the (a) reactive monomers / reactive resins, (b) the initiator, (c) the photoredox catalyst, (d) optionally the polymeric film-forming matrix, and optionally other components, which is obtained as a sum in wt.%.

[0049] Solvents or water are used only for the production process and are not included in the overall mixture of the components of the reactive adhesive according to the invention in this consideration. Polymer film-forming matrix

[0050] In a preferred embodiment of the invention, the reactive adhesive comprises a polymeric film-forming matrix. The purpose of this polymeric film-forming matrix is ​​to form an inert framework for the reactive monomers / reactive resins and the other substances, so that these are not present in liquid form. The polymeric film-forming matrix is ​​a polymer that thus serves to physically bind or embed the reactive monomers / reactive resins and the other substances. The polymeric film-forming matrix thus gives the reactive adhesive according to the invention a shape and prevents or delays flow. Among other things, the polymeric film-forming matrix should make it possible to advantageously supply the reactive adhesive according to the invention as a film or foil. This ensures easier handling.

[0051] In this context, inert means that the reactive monomers / reactive resins do not essentially react with the polymeric film-forming matrix under suitably chosen conditions (e.g., at sufficiently low temperatures).

[0052] Suitable polymeric film-forming matrices for use in the present invention are thermoplastic polymers, such as polyurethanes, polyesters or copolyesters, polyamides or copolyamides, polyacrylic acid esters, acrylic acid ester copolymers, polymethacrylic acid esters, and methacrylic acid ester copolymers. Chemically or physically cross-linked substances of the aforementioned compounds are also conceivable. In addition, blends of different thermoplastic polymers can also be used. Furthermore, elastomers, thermoplastic elastomers, and thermosets, alone or in mixtures, are also conceivable as polymeric film-forming matrices.

[0053] Thermoplastic polymers, especially semicrystalline ones, are preferred. Particularly preferred are thermoplastic polymers with a crystalline melting point and softening point also below 100 °C. In this context, the term softening point refers to the temperature at which the thermoplastic granules bond to themselves. If the component of the polymeric film-forming matrix is ​​a semicrystalline thermoplastic polymer, then, in addition to its softening point (which is related to the melting of the crystallites), it very preferably has a glass transition temperature of at most 25 °C, preferably at most 0 °C.

[0054] In a preferred embodiment according to the invention, a thermoplastic polyurethane is used. Preferably, the thermoplastic polyurethane has a softening temperature of less than 100 °C, in particular less than 80 °C.

[0055] In a particularly preferred embodiment according to the invention, Desmomelt®< 530 is used as a polymeric film-forming matrix, which is commercially available from Covestro AG, Leverkusen, Germany. Desmomelt®< 530 is a hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer.

[0056] According to the invention, the amount of the polymeric film-forming matrix is ​​in the range of approximately 10 to 90 wt.%, preferably approximately 20 to 70 wt.%, based on the total mixture of the components of the reactive adhesive according to the invention. More preferably, 25 to 60 wt.%, and most preferably approximately 30 to 50 wt.%, of the polymeric film-forming matrix is ​​used, based on the total mixture of the components of one of the reactive adhesives according to the invention. The total mixture of the components of the reactive adhesive according to the invention refers here to the total amount of the (a) reactive monomers / reactive resins, (b) the initiator, (c) the photoredox catalyst, (d) the polymeric film-forming matrix, and optionally other components, which is obtained as a sum in wt.%.Solvents or water are used only for the production process and are not included in the overall mixture of the components of the reactive adhesive according to the invention in this consideration. Other components of the reactive adhesive

[0057] The reactive adhesive of the present invention may optionally contain further additives and / or excipients known in the art. These include, for example, fillers, dyes, nucleating agents, rheological additives (e.g., pyrogenic silica), expanding agents, adhesive-strengthening additives (adhesion promoters, in particular silanes and tackifier resins), compounding agents, plasticizers, and / or aging, light, and UV protection agents, for example, in the form of primary and secondary antioxidants. The further components of the reactive adhesive films according to the invention may also be reactive monomers. This is particularly preferred in the case of the silane adhesion promoters. In this context, 3-trimethoxysilylpropyl methacrylate (CAS No.: 2530-85-0), available under the trade name Dynasylan® MEMO from Evonik AG, Essen, is preferably used. Reactive adhesive film

[0058] In a preferred embodiment of the invention, the reactive adhesive is in the form of a film. As used herein, the term "adhesive film" (or adhesive layer, adhesive film) shall encompass a complete or incomplete application of the adhesive mixture, as described below. For example, a dot-like application of the adhesive that does not completely cover the substrate surface(s) to be bonded can also lead to a permanent bond within the meaning of the present invention.

[0059] In a preferred embodiment according to the invention, the reactive adhesive film according to the invention comprises a mixture of the following components: 4-acryloylmorpholine, N-vinylcaprolactam, di(trimethylolpropane)tetraacrylate, diisopropylbenzene hydroperoxide, tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate, thermoplastic polyurethane, in particular Desmomelt ®< 530 and 3-trimethoxysilylpropyl methacrylate.

[0060] A particularly preferred embodiment according to the invention contains approximately 45.0-65.0 wt.% of the reactive monomers, approximately 0.5 to 6.0 wt.% diisopropylbenzene hydroperoxide, approximately 0.1-1.0 wt.% photoredox catalyst, approximately 30.0 to 50.0 wt.% thermoplastic polyurethane, and approximately 0.5 to 2.0 wt.% silane, based on the total mixture of the components of the reactive adhesive film according to the invention.

[0061] As used herein, the total mixture of the components of the reactive adhesive film according to the invention refers to the total amount of the (a) reactive monomers / reactive resins, (b) the initiator, (c) the photoredox catalyst, (d) the polymeric film-forming matrix, and the other components present, which is obtained as a sum in weight percent (wt.%).

[0062] The reactive adhesive film according to the invention typically has a layer thickness in the range of about 20 to 200 µm, preferably about 30 to 100 µm, more preferably about 40 to 60 µm, and particularly preferably about 50 µm. To produce greater layer thicknesses, it can be advantageous to laminate several adhesive film layers together.

[0063] Furthermore, the reactive adhesive film according to the invention is characterized by its preferably tacky properties. According to Römpp, tacky materials are defined as viscoelastic adhesives (Römpp Online 2013, document number RD-08-00162) whose cured, dry film is permanently tacky at room temperature and remains adhesive. Tacky adhesion occurs immediately on almost all substrates with slight contact pressure. Here, slight contact pressure refers to a pressure greater than 0 bar, applied for a duration greater than 0 seconds.

[0064] Furthermore, the reactive adhesive film of the invention can comprise further films, layers, adhesives as well as permanent and / or temporary carriers.

[0065] Suitable carrier materials are known to experts in the field. For example, films (polyester, PET, PE, PP, BOPP, PVC, polyimides), nonwovens, foams, fabrics, and / or woven films can be used as permanent carriers. Temporary carriers should be provided with a release liner, which typically consists of a silicone release agent or a fluorinated release agent, or is of a polyolefinic nature (HDPE, LDPE).

[0066] In some cases, it may be necessary to pretreat the surfaces of the substrates to be bonded using a physical, chemical, and / or physicochemical process. For example, applying a primer or adhesion promoter is advantageous. Corona, plasma, or flame pretreatment can also be beneficial. Substrates

[0067] Substrates suitable for bonding with the reactive adhesive / adhesive film according to the invention include metals, glass, wood, concrete, stone, ceramics, textiles, and / or plastics. The substrates to be bonded can be the same or different. They can be transparent or opaque.

[0068] In a preferred embodiment, the reactive adhesive / adhesive film according to the invention is used for bonding metals, glass, and plastics. In a particularly preferred embodiment according to the invention, polycarbonates, polyamide, and anodized aluminum are bonded.

[0069] The metal substrates to be bonded can generally be made from all common metals and metal alloys. Preferred metals include aluminum, stainless steel, steel, magnesium, zinc, nickel, brass, copper, titanium, ferrous metals, and alloys. The parts to be bonded can also be composed of different metals.

[0070] Suitable plastic substrates include, for example, acrylonitrile butadiene styrene copolymers (ABS), polycarbonates (PC), ABS / PC blends, PMMA, polyamides, glass fiber reinforced polyamides, polyvinyl chloride, polyvinyl fluoride, cellulose acetate, cycloolefin copolymers, liquid crystal polymers (LCP), polylactide, polyetherketones, polyetherimide, polyethersulfone, polymethacrylmethylimide, polymethylpentene, polyphenyl ether, polyphenylene sulfide, polyphthalamide, polyurethanes, polyvinyl acetate, styrene acrylonitrile copolymers, polyacrylates or polymethacrylates, polyoxymethylene, acrylate-styrene-acrylonitrile copolymers, polyethylene, polystyrene, polypropylene and / or polyesters, such as polybutylene terephthalate (PBT) and / or polyethylene terephthalate (PET).

[0071] Substrates can be painted, printed, vapor-coated or sputtered.

[0072] The substrates to be bonded can assume any shape required for the use of the resulting composite body. In their simplest form, the substrates are flat. Furthermore, three-dimensional substrates, such as those that are inclined, can also be bonded with the reactive adhesive according to the invention. The substrates to be bonded can also fulfill a wide variety of functions, such as housings, viewing windows, stiffening elements, etc. Method for producing a reactive adhesive and adhesive film

[0073] The process begins no later than the addition of the photoredox catalyst and must be carried out in the absence of UV light or visible light of the wavelength that excites the respective photoredox catalyst. These are typically wavelengths below 500 nm. This exclusion can usually be achieved using yellow light filters.

[0074] The reactive adhesives and adhesive films according to the invention are produced by the processes described below: In a first step, the ingredients are dissolved or finely dispersed in one or more solvents and / or water. Alternatively, no solvent and / or water is necessary, since the ingredients are already completely soluble in each other (optionally under the influence of heat and / or shear). Suitable solvents are known in the prior art, with solvents preferably used in which at least one of the ingredients exhibits good solubility. Acetone is particularly preferred.

[0075] As used herein, the term ingredient includes at least one reactive monomer / reactive resin, the initiator, the photoredox catalyst, optionally the polymeric film-forming matrix, and optionally any other components present, as defined above.

[0076] The dissolved or finely dispersed ingredients are then mixed in a second step. Standard stirring equipment is used to prepare the mixture. The solution may also be heated. If necessary, the ingredients are simultaneously dissolved or finely dispersed and mixed.

[0077] In a third step, a release liner, release paper, carrier material, or pressure-sensitive adhesive or adhesive film is coated with the mixture of dissolved or finely dispersed ingredients from step 2. The coating is carried out using standard techniques known in the prior art.

[0078] After coating, the solvent is removed in a fourth step by evaporation.

[0079] If necessary, the reactive adhesive film can be wound into a roll in a further step.

[0080] For storage, the reactive adhesive films according to the invention are covered with a separating liner or paper.

[0081] Alternatively, the reactive adhesive films according to the invention are produced solvent-free by extrusion, hot melt nozzle coating or calendering. Composite body

[0082] Finally, according to the invention, a composite body is provided which is joined by the reactive adhesive / adhesive film according to the invention, as defined above. Product features

[0083] The reactive adhesive / adhesive film according to the invention exhibits outstanding product properties that were not foreseeable even for those skilled in the art. The adhesive / adhesive film can be cured using a commercially available mercury vapor UV lamp (for example, the UVA CUBE 100 from Hönle, http: / / www.hoenle.de). The irradiation time when using the UVA CUBE 100 is approximately 1 to 3 minutes, depending on the distance of the adhesive / adhesive film from the lamp. After irradiation, the adhesive / adhesive film does not cure immediately. It initially remains liquid or tacky. Bonding or joining of the substrates is possible within a period of three minutes or slightly longer after irradiation. In other words, the adhesive / adhesive film according to the invention has an open time of at least three minutes after irradiation and thus the initiation of curing.The adhesive / adhesive film according to the invention cures completely within approximately 24 hours after irradiation. Curing also occurs in the dark. Therefore, non-transparent substrates can also be bonded with the adhesive / adhesive film according to the invention.

[0084] The adhesive / adhesive film according to the invention achieves high bond strengths. In tensile shear tests, values ​​greater than 10 MPa are typically achieved for bonds of polycarbonate test specimens (see examples). This order of magnitude is generally referred to as "structural". In push-out tests, values ​​greater than 4 MPa are achieved for bonds of polycarbonate test specimens (see examples). Experimental section

[0085] The following examples serve to illustrate the present invention, but should in no way be understood as a limitation of the scope of protection. Preparation of a solution of the film former matrix Polyurethane (PU) solution:

[0086] A 20% acetone solution of the film-forming polymer is prepared by first weighing 120 g of Desmomelt®< 530 and 480 g of acetone into a screw-top jar and sealing the jar. The Desmomelt®< 530 is then completely dissolved by rolling the jar on a rolling bench for several days. Depending on the rolling speed, this process takes approximately one to seven days. Alternatively, the acetone solution can also be prepared by stirring the Desmomelt®< 530 granules in acetone using a standard laboratory stirrer. Example 1 Creating a self-adhesive, reactive film

[0087] 174.0 g of the 20% acetone solution of Desmomelt®< 530 (PU solution) are mixed with 42.9 g of 4-acryloylmorpholine, 11.6 g of N-vinylcaprolactam, 3.5 g of di(trimethylpropane)tetraacrylate, 1.2 g of 3-trimethoxysilylpropyl methacrylate, and 11.6 g of Peroxan®< IHP-50 using a standard laboratory stirrer for 60 minutes. Peroxan®< IHP-50 is a 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene from Pergan. 11.6 g of Peroxan®< IHP-50 thus corresponds to 5.8 g of diisopropyl hydroperoxide and 5.8 g of diisopropylbenzene. All further procedures are performed under yellow light. 0.2 g of Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate is added and mixed in for 30 minutes.

[0088] The resulting homogeneous mixture is spread onto a siliconized polyester film (release liner) using a standard laboratory spreading table (for example, from SMO, Sondermaschinen Oschersleben GmbH) and a spreading knife. The acetone is then evaporated for 10 minutes in a circulating air drying oven at 60°C. The spreading gap is adjusted so that a 50 µm thick film is obtained after the solvent has evaporated. The resulting tacky, reactive adhesive film is covered with a second siliconized polyester film (release liner) and sealed airtight, moisture-proof, and lightproof in an aluminum-plastic composite bag (for example, "Moisture Barrier Bags" from Helmut Boss Verpackungsmaschinen KG). The tacky, reactive adhesive film is stored there until use / testing.

[0089] The percentage composition of the self-adhesive, reactive adhesive film and the quantities used to prepare the preceding solution are listed in the following table: Example 1, solution and tacky, reactive adhesive film

[0090] % solids by weight* Weight (g) with solvent Desmomelt ®< 530** 34,8 Desmomelt® < 530 solution in acetone (20 wt.% Desmomelt® < 530 in acetone) 174,0 4-Acryloylmorpholine 42,9 42,9 N-Vinylcaprolactam 11,6 11,6 Di(trimethylolpropane) tetraacrylate 3,5 3,5 Dynasylan ®< Memo*** 1,2 1,2 Diisopropyl hydroperoxide 5,8 Peroxan® < IHP-50**** 11,6 Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate (CAS No.: 50525-27-4) 0,2 0,2 sum 100,0 245,0 * Solids are defined here as all substances that are not solvents. Acetone and diisopropylbenzene are considered solvents. ** Hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer, Covestro. *** 3-Trimethoxysilylpropyl methacrylate, Evonik. **** 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, Pergan.

[0091] The solutions and self-adhesive, reactive adhesive films of the other examples are prepared in an analogous manner to Example 1.

[0092] The following tables provide information about the compositions of the solutions and self-adhesive, reactive adhesive films in the further examples. Example 2, solution and tacky, reactive adhesive film

[0093] % solids by weight* Weight (g) with solvent Desmomelt ®< 530** 36,5 Desmomelt® < 530 solution in acetone (20 wt.% Desmomelt® < 530 in acetone) 182,5 4-Acryloylmorpholine 45,0 45,0 N-Vinylcaprolactam 12,2 12,2 Di(trimethylolpropane) tetraacrylate 3,7 3,7 Dynasylan ®< Memo*** 1,2 1,2 Diisopropyl hydroperoxide 1,2 Peroxan® < IHP-50**** 2,4 Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate (CAS No.: 50525-27-4) 0,2 0,2 sum 100,0 247,2 * Solids are defined here as all substances that are not solvents. Acetone and diisopropylbenzene are considered solvents. ** Hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer, Covestro. *** 3-Trimethoxysilylpropyl methacrylate, Evonik. **** 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, Pergan. Example 3, solution and tacky, reactive adhesive film

[0094] % solids by weight* Weight (g) with solvent Desmomelt ®< 530** 41,6 Desmomelt® < 530 solution in acetone (20 wt.% Desmomelt® < 530 in acetone) 207,8 4-Acryloylmorpholine 9,7 9,7 SR 531*** 41,5 41,5 Diisopropyl hydroperoxide 6,9 Peroxan® < IHP-50**** 13,8 Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate (CAS No.: 50525-27-4) 0,3 0,3 sum 100,0 273,1 * Solids are defined here as all substances that are not solvents. Acetone and diisopropylbenzene are considered solvents. ** Hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer, Covestro. *** (5-Ethyl-1,3-dioxan-5-yl)methyl acrylate, Sartomer-Arkema. **** 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, Pergan. Example 4, solution and tacky, reactive adhesive film

[0095] % solids by weight* Weight (g) with solvent Desmomelt ®< 530** 42,8 Desmomelt® < 530 solution in acetone (20 wt.% Desmomelt® < 530 in acetone) 214,0 4-Acryloylmorpholine 10,0 10,0 SR 531*** 42,9 42,9 Trimethyloylpropane propoxylate triacrylate 1,4 1,4 Dynasylan ®< Memo**** 1,4 1,4 Diisopropyl hydroperoxide 1,4 Peroxan® < IHP-50***** 2,8 Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate (CAS No.: 50525-27-4) 0,1 0,1 sum 100,0 272,6 * Solids are defined here as all substances that are not solvents. The solvents in this context are acetone and diisopropylbenzene. ** Hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer, Covestro. *** (5-Ethyl-1,3-dioxan-5-yl)methyl acrylate, Sartomer-Arkema. **** 3-Trimethoxysilylpropyl methacrylate, Evonik. ***** 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, Pergan. Example 5, solution and tacky, reactive adhesive film

[0096] % solids by weight* Weight (g) with solvent Desmomelt ®< 530** 42,1 Desmomelt® < 530 solution in acetone (20 wt.% Desmomelt® < 530 in acetone) 210,7 4-Acryloylmorpholine 9,8 9,8 SR 531*** 42,2 42,2 BIS-DMA 1,4 1,4 Dynasylan ®< Memo**** 1,4 1,4 Diisopropyl hydroperoxide 2,8 Peroxan® < IHP-50***** 5,6 Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate (CAS No.: 50525-27-4) 0,3 0,3 sum 100,0 271,4 * Solids are defined here as all substances that are not solvents. The solvents in this context are acetone and diisopropylbenzene. ** Hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer, Covestro. *** (5-Ethyl-1,3-dioxan-5-yl)methyl acrylate, Sartomer-Arkema. **** 3-Trimethoxysilylpropyl methacrylate, Evonik. ***** 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, Pergan. Example 6, solution and tacky, reactive adhesive film

[0097] % solids by weight* Weight (g) with solvent Desmomelt ®< 530** 34,8 Desmomelt® < 530 solution in acetone (20 wt.% Desmomelt® < 530 in acetone) 174,0 4-Acryloylmorpholine 42,9 42,9 N-Vinylcaprolactam 11,6 11,6 Di(trimethylolpropane) tetraacrylate 3,5 3,5 Dynasylan ®< Memo*** 1,2 1,2 Diisopropyl hydroperoxide 5,8 Peroxan® < IHP-50**** 11,6 Ir(ppy) 3 (CAS No.: 94928-86-6) 0,2 0,2 sum 100,0 245,0 * Solids are defined here as all substances that are not solvents. Acetone and diisopropylbenzene are considered solvents. ** Hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer, Covestro. *** 3-Trimethoxysilylpropyl methacrylate, Evonik. **** 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, Pergan. Example 7, solution and tacky, reactive adhesive film

[0098] % solids by weight* Weight (g) with solvent Desmomelt ®< 530** 34,8 Desmomelt® < 530 solution in acetone (20 wt.% Desmomelt® < 530 in acetone) 174,0 4-Acryloylmorpholine 42,9 42,9 N-Vinylcaprolactam 11,6 11,6 Di(trimethylolpropane) tetraacrylate 3,5 3,5 Dynasylan ®< Memo*** 1,2 1,2 Diisopropyl hydroperoxide 5,8 Peroxan® < IHP-50**** 11,6 Ir(Fppy) 3 (CAS No.: 387859-70-3) 0,2 0,2 sum 100,0 245,0 * Solids are defined here as all substances that are not solvents. Acetone and diisopropylbenzene are considered solvents. ** Hydroxyl-terminated, largely linear, thermoplastic, strongly crystallizing polyurethane elastomer, Covestro. *** 3-Trimethoxysilylpropyl methacrylate, Evonik. **** 50 wt% solution of diisopropyl hydroperoxide in diisopropylbenzene, Pergan. Tensile shear strength Sample preparation for determining tensile shear strength

[0099] Rectangular blanks measuring 25.0 mm x 12.5 mm are die-cut from the self-adhesive, reactive adhesive films to be examined, each of which is covered on both sides with a release liner. The release papers are then peeled off one side of each blank.

[0100] The die-cut reactive adhesive film blanks are precisely positioned on the end of a black, non-transparent polycarbonate test specimen (available, for example, from Rocholl, Aglasterhausen) measuring 100.0 mm x 25.0 mm x 5.0 mm. The blanks then adhere to the test specimen. Finally, the remaining release liner on the blanks is removed. Irradiation for determining tensile shear strength

[0101] Irradiation was performed using the Hönle UVA CUBE 100, which was equipped with a mercury vapor lamp. The distance between the reactive adhesive films and the mercury vapor lamp was adjusted to a few millimeters using a lab stand. The irradiation time was one minute in each case. The test specimens were then joined. The time interval between the end of irradiation and joining the test specimens was varied, ranging from one to five minutes. Bonding for determining tensile shear strength

[0102] The second polycarbonate test specimens were each placed flush with one end onto the prepared specimens, as described above. Each sample consisted of the first polycarbonate test specimen and the irradiated die-cut piece adhered to it, resulting in an overlapping composite of first polycarbonate test specimen / irradiated die-cut piece / second polycarbonate test specimen, as described in DIN EN 1465. The overlap length was 12.5 mm in each case. The overlap area was 312.5 mm² in each case. The overlapping composites of first test specimen / irradiated and thus reactive adhesive / second test specimen were placed on a table. A 2 kg weight was placed on the second test specimen in each case. The composite was subjected to the continuous pressure of the weight for 60 seconds at room temperature (compression time). The weight was then removed. The composite was subsequently stored for 24 hours at 23°C and 50% relative humidity.This resulted in a gradual curing reaction of the adhesive and a gradually increasing adhesion between the adhesive and the respective polycarbonate test specimens. This led to a bond with a gradual increase in strength over time, significantly exceeding the initial strength achieved through pressure-sensitive adhesion. The tensile shear strength (fresh values) was then determined.

[0103] To test storage stability, the self-adhesive, reactive films, sealed airtight, moisture-proof, and lightproof in an aluminum-plastic composite bag, were stored for 6 months at 23°C. The tensile shear strength was then determined again, including sample preparation, irradiation, and bonding, as described. The time interval between the end of irradiation and joining the test specimens was always one minute.

[0104] Similarly, polyamide / polyamide and aluminum / aluminum bonding was also produced. The corresponding non-transparent polyamide test specimens had the same dimensions as the polycarbonate test specimens, while the aluminum test specimens (alloy 5005A (AIMG1), anodized E6 EV1) were only 2 mm thick and otherwise had the same dimensions. All test specimens used are available from Rocholl.

[0105] The polyamide test specimens were briefly pretreated with the Piezobrush ®< PZ2 handheld device (relyon plasma GmbH) immediately before bonding. Determination of tensile shear strength

[0106] Determining the tensile shear strength of overlapping adhesive joints provides information about the shear strength of a double-sided adhesive product. The determination was carried out according to DIN EN 1465 using a tensile testing machine. The test speed was 10 mm / min. All measurements were performed in a climate-controlled room at 23°C and 50% relative humidity. Push-out test

[0107] The push-out test allows statements to be made about the bond strength of a double-sided adhesive product in the direction of the adhesive layer normal. Sample preparation for the push-out test

[0108] Round blanks with a diameter of 21 mm were die-cut from the self-adhesive reactive films to be tested, each of which was covered on both sides with a release liner. The release liners were then removed from one side of each blank. The blanks were then precisely positioned onto a round, 5 mm thick sample disc made of black-tinted, non-transparent polycarbonate ("disc," first substrate, first test specimen), also with a diameter of 21 mm. The blanks now adhered perfectly to the disc. The remaining release liner was then removed from the blanks. The discs were now coated with the self-adhesive reactive films. Irradiation for the push-out test

[0109] Irradiation was performed using the Hönle UVA CUBE 100, which was equipped with a mercury vapor lamp. The distance between the reactive adhesive films and the mercury vapor lamp was adjusted to a few millimeters using a lab stand. The irradiation time was one minute in each case. The test specimens were then joined. The time interval between the end of irradiation and joining the test specimens was varied, ranging from one to five minutes. Adhesive for the push-out test

[0110] The second substrate (second test specimen) was a 5 mm thick square perforated plate, also made of black-tinted, non-transparent polycarbonate. The sides were each 40 mm long. The hole was centrally located and round, with a diameter of 9 mm.

[0111] The round specimens, each fitted with an irradiated die, were positioned on the perforated plate with the exposed side of the die facing upwards, ensuring that the center of the round specimen and the center of the perforation in the plate were aligned. The assembly, held together by the adhesive properties of the dies and consisting of the square perforated plate, the irradiated die, and the disc, was then placed on a table with the square perforated plate facing downwards. A 2 kg weight was placed on the disc. The assembly was subjected to the continuous pressure of the weight for 60 seconds (compression time) at 23°C. The weight was then removed. The assembly was subsequently stored for 24 hours at 23°C and 50% relative humidity.This resulted in a gradually progressing hardening reaction within the die-cut pieces and a gradually increasing adhesion between the die-cut pieces (reactive adhesive films) and the substrates (test specimens). This led to bonding with a gradual increase in strength over time.

[0112] Then the push-out tests (freshness values) were carried out.

[0113] Similarly, polyamide and aluminum composite panels were also produced for push-out tests. In all cases, the "discs" were sample discs made of black-dyed, non-transparent polycarbonate. The square perforated plates were either non-transparent polyamide or... test specimens and had the same dimensions as the polycarbonate perforated plates, or they were aluminum test specimens (alloy 5005A (AIMG1), anodized E6 EV1). These were only 2 mm thick and otherwise had the same dimensions. All test specimens used are available from Rocholl.

[0114] The polyamide test specimens were briefly pretreated with the Piezobrush ®< PZ2 handheld device (relyon plasma GmbH) immediately before bonding. Conducting the push-out test

[0115] A mandrel clamped in a tensile testing machine was used to press through the hole in the perforated plate at a constant speed of 10 mm / min perpendicularly onto the round test specimen ("disc") (i.e., parallel to the normal vector to the plane of the test specimen; centered on the center of the hole) until the adhesive bond failed sufficiently to register a pressure drop of 50%. The pressure acting immediately before the pressure drop is the maximum pressure Pmax. This value corresponds to the push-out value [N / mm²2] given in the table. All measurements were performed in an air-conditioned room at 23 °C and 50% relative humidity. Results Tensile shear strength and push-out (freshness values) Bonding of polycarbonate test specimens

[0116] Tensile shear strength Push-Out Result [MPa] [MPa] [MPa] [MPa] [MPa] [MPa] Open time after radiation therapy 1 minute 3 minutes 5 minutes 1 minute 3 minutes 5 minutes Example 1 13,6 (K) 14,0 (K) 5,1 (A) 6,3 (K) 6,8 (K) 1,8 (A) Example 2 11,2 (K) 10,7(K) 3,2 (A) 5,1 (K) 5,3 (K) 1,6 (A) Example 3 10,9 (K) 10,3 (K) 2,8(A) 6,6 (K) 6,3 (K) 1,8 (A) Example 4 11,7 (K) 12,2 (K) 3,9 (A) 5,1 (K) 5,4 (K) 2,4 (A) Example 5 12,3 (K) 12,0 (K) 4,2 (A) 5,4 (K) 5,4 (K) 2,6 (A) Example 6 11,7 (K) 11,2 (K) 1,7 (A) 5,8 (K) 5,3 (K) 1,1 (A) Example 7 10,4 (K) 10,9 (K) 1,1 (A) 4,8 (K) 5,0 (K) 0,7 (A) Fracture patterns: A=Adhesive K=Cohesive M=Mixed fracture Tensile shear strength for testing bearing stability Bonding of polycarbonate test specimens Open time after irradiation: 1 minute each time

[0117] Tensile shear strength Freshness After ½ year of storage of the non-irradiated, adhesive, reactive adhesive films at 23°C [MPa] [MPa] Example 1 13,6 (K) 13,1 (K) Example 2 11,2 (K) 11,4 (K) Example 3 10,9 (K) 10,1 (K) Example 4 11,7 (K) 10,2 (K) Example 5 12,3 (K) 11,8 (K) Example 6 11,7 (K) 9,1 (K) Example 7 10,4 (K) 9,8 (K) Fracture patterns: A=Adhesive K=Cohesive M=Mixed fracture Tensile shear strength and push-out (freshness values) Bonding of polyamide and aluminium test specimens Open time after irradiation: 1 minute each time

[0118] Polyamide, pretreated with a piezo brush Anodized aluminum Tensile shear strength Push-Out Tensile shear strength Push-Out [MPa] [MPa] [MPa] [MPa] Example 1 1,7 (A) 2,2 (A) 8,0 (A) 1,0 (A) Example 2 4,9 (A) 3,7 (M) 9,2 (A) 3,3 (A) Example 3 4,9 (A) 2,2 (M) 5,5 (A) 1,5 (A) Example 4 2,9 (A) 1,0 (A) 4,0 (A) 1,6 (A) Example 5 4,1 (A) 2,6 (A) 5,9 (A) 3,6 (M) Example 6 3,8 (A) 2,9 (A) 4,4 (A) 3,2 (A) Example 7 3,2 (A) 2,6 (A) 3,6 (A) 2,9 (M) Fracture patterns: A=Adhesive K=Cohesive M=Mixed fracture Discussion of the results

[0119] The reactive adhesive / adhesive film according to the invention can be cured with the light of a mercury vapor lamp. It represents a significant improvement over the prior art in that, firstly, it does not cure immediately after irradiation, but has an open time of approximately 3 minutes, and secondly, it continues to cure in the dark, making it suitable for bonding non-transparent substrates. Furthermore, high bond strengths are achieved on adhesive-friendly substrates such as polycarbonate, both in the tensile shear test and in the push-out test. On substrates that are generally difficult to bond, such as polyamide, bond strengths can be achieved that are acceptable for many applications.

Claims

1. A reactive adhesive comprising (a) at least one reactive monomer or reactive resin, and (b) an initiator, in particular a radical initiator, characterized in that the adhesive further comprises (c) a transition metal complex with ruthenium or iridium as the central atom, wherein the reactive monomer or reactive resin (a) comprises at least one agent selected from acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, higher functional methacrylates, vinyl compounds and / or oligomeric or polymeric compounds with carbon-carbon double bonds, as well as crosslinking reactive monomers such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates, as well as higher functional methacrylates, particularly preferably tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-(1,1-dimethylethyl)cyclohexyl methacrylate, 4-acryloylmorpholine, 4-methacryloylmorpholine, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl methacrylate, (5-ethyl-1,3-dioxan-5-yl)methyl acrylate, bisphenol A glycerolate dimethacrylate (BIS-GMA), bisphenol A dimethacrylate (BIS-DMA) as well as the crosslinking reactive monomers ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethyloylpropane propoxylate triacrylate, trimethyloylpropane triacrylate and / or di(trimethylolpropane)tetraacrylate, wherein the transition metal complex comprises - ruthenium as the central atom and bipyridine or a monosubstituted or polysubstituted bipyridine derivative as ligands, or - iridium as the central atom and phenylpyridine or a monosubstituted or polysubstituted phenylpyridine derivative as ligands.

2. The reactive adhesive as claimed in claim 1, characterized in that the transition metal complex comprises [tris(2,2'-bipyridyl)ruthenium(II)]2+, tris[2-(2,4-difluorophenyl)pyridine]iridium(III) or tris(2-phenylpyridinato)iridium(III).

3. The reactive adhesive as claimed in one of the preceding claims, characterized in that the radical initiator (b) comprises a peroxide, preferably a hydroperoxide, particularly preferably α,α-dimethylbenzyl hydroperoxide, or diisopropylbenzene hydroperoxide.

4. The reactive adhesive as claimed in one of the preceding claims, comprising (d) a polymeric film-former matrix, preferably a thermoplastic polymer, an elastomer and / or a thermoplastic elastomer as the polymeric film-former matrix, particularly preferably a thermoplastic polyurethane as the film-former matrix.

5. The reactive adhesive as claimed in one of the preceding claims, consisting of or comprising 10 to 90 % by weight of at least one reactive monomer or reactive resin, 0.1 to 10 % by weight of initiator, in particular radical initiator, up to 5 % by weight of transition metal complex, 10 to 90 % by weight of polymeric film-former matrix, preferably 40 to 70 % by weight of at least one reactive monomer or reactive resin, 0.2 to 8 % by weight of initiator, in particular radical initiator, up to 5 % by weight of transition metal complex, 20 to 70 % by weight of polymeric film-former matrix.

6. The reactive adhesive as claimed in one of the preceding claims, characterized in that it is pressure-sensitive.

7. The reactive adhesive as claimed in one of the preceding claims, in film form.

8. The reactive adhesive in film form as claimed in claim 7, comprising further films, layers, adhesives, carriers, release papers and / or release liners.

9. A method for the production of a reactive adhesive as claimed in one of claims 1 to 6 or of a reactive adhesive film as claimed in one of claims 7 or 8, characterized in that the method - under the exclusion of UV light or visible light with a wavelength by which the respective transition metal complex is excited - comprises the following steps:

1. dissolving and / or finely dispersing the constituents in one or more solvent(s) and / or water, 2. mixing the dissolved or finely dispersed constituents, 3. coating a release liner or release paper, a carrier material or a pressure-sensitive adhesive or the substrate to be bonded with the mixture of constituents which have been dissolved or finely dispersed in accordance with step 2, 4. evaporating off the solvent and / or water, 5. optionally, winding the reactive adhesive film up into a roll, wherein the constituents comprise (a) at least one reactive monomer or reactive resin, (b) an initiator, in particular a radical initiator, (c) a transition metal complex with a ruthenium or iridium as the central atom, optionally, (d) a polymeric film-former matrix as well as optional further additives and / or auxiliary materials.

10. Use of a reactive adhesive or adhesive film as claimed in one of claims 1 to 6 or adhesive film as claimed in one of claims 7 or 8 for bonding materials produced from metal, wood, glass, ceramic and / or plastics.

11. A composite body comprising at least two bonding surfaces which are connected together by the reactive adhesive as claimed in one of claims 1 to 6 or the adhesive film as claimed in one of claims 7 or 8.