Photocurable reactive adhesive film having improved storage stability after exposure to light

Abstract

The present invention relates to a photocurable, reactive, pressure-sensitive adhesive film. The adhesive film according to the invention makes it possible to achieve structural bond strengths. The adhesive film comprises (a) at least one free-radically polymerizable compound, and (b) at least one free-radical initiator, and (c) at least one photoredox catalyst, and (d) at least one carbon black. The adhesive film has improved storage stability after exposure to ambient light compared to the prior art.

Description

[0001] Light-curing reactive adhesive film with improved storage stability after exposure to light.

[0002] Description

[0003] Technical field of the invention

[0004] The present invention relates to a light-curing, reactive, pressure-sensitive adhesive film, a method for producing the reactive adhesive film, the use of the adhesive film for bonding various materials, such as plastic, metal, glass and / or ceramic, and a composite body comprising at least two bonding surfaces which are connected to each other by the cured reactive, pressure-sensitive adhesive film.

[0005] General state of the art

[0006] Reactive, radical-curing adhesive films, whose curing can be initiated with light, especially UV light, are known. The reactive chemistry, or the chemistry for curing such adhesive films, is based on reactive acrylic monomers that undergo radical polymerization upon initiation with (UV) light. The curing reaction is started with the help of a photoinitiator, which decomposes in a photolysis reaction after absorption of (UV) light, thus forming reactive species that trigger the radical polymerization. A disadvantage can be the speed of the curing reaction, especially when bonding non-transparent substrates. Once the reaction has been initiated, there is usually insufficient time to join the components to be bonded. Therefore, such adhesive films are only suitable for bonding (UV)-transparent substrates, as irradiation can then occur through the components after they have been joined.A further disadvantage of this type of adhesive film is that the polymerization does not proceed as a dark reaction. DE 102019209513 A1 describes a reactive adhesive film based on acrylic monomers that does not exhibit these disadvantages of the prior art. However, its insufficient resistance to damp heat for many applications has proven to be a disadvantage.

[0007] EP 4159775 B1 proposes a reactive adhesive film with improved resistance to damp heat, with which very high, so-called structural bond strengths can be achieved.

[0008] EP 3390553 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 the requirement for laser light.

[0009] EP 3126402 A1 discloses a method in which a radical polymerization reaction is triggered by plasma treatment of an adhesive film 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.

[0010] A disadvantage of all the aforementioned reactive, radically curing adhesive films, whose curing is initiated with light, especially UV light, can be the fact that they must be protected from light of the wavelength that initiates curing during production, storage and further processing, for example during the converting process, since after such light exposure, depending on the wavelength, light dose and initiator type, a spontaneous curing reaction or reduced further storage stability can occur.

[0011] The object of the present invention is to provide an improved, light-curing, reactive, pressure-sensitive adhesive film with which high bond strengths can be achieved, exceeding those attainable with non-reactive pressure-sensitive adhesive films. The limit is, in particular, approximately 1 MPa in the push-out test. Bond strengths of approximately 5 or greater than 5 MPa in the push-out test are considered structural in this document. These values ​​should be achievable with advantageous embodiments. Furthermore, the light-curing, reactive, pressure-sensitive adhesive film should exhibit improved storage stability compared to the prior art after exposure to light during manufacturing, storage, or further processing, for example, during the converting process. Curing should be induced by blue LED light or UV LED light.The adhesive film should cure slowly enough to allow the components to be joined after a certain time interval following initiation, thus enabling the bonding of even opaque components. The adhesive film should continue to cure in the dark after initiation and joining of the components.

[0012] Solution to the task

[0013] This problem is solved by a light-curing, reactive, tacky adhesive film according to the main claim, comprising (a) at least one radically polymerizable compound, (b) at least one radical initiator, (c) at least one photoredox catalyst, and (d) at least one carbon black. The dependent claims relate to advantageous embodiments of the light-curing, reactive, tacky adhesive film, the process for its production, and possible uses.

[0014] Detailed description of the invention:

[0015] All descriptions apply to the adhesive film according to the invention, the adhesive tape according to the invention, the method according to the invention for producing the adhesive film, the composite body according to the invention, and the use of the adhesive film or adhesive tape according to the invention.

[0016] The invention also encompasses all features that are the subject matter of any dependent claims. Furthermore, the invention encompasses combinations of individual features with one another, including combinations of different preferred features. Thus, for example, the invention encompasses the combination of a first feature designated as "preferred" with a second feature designated as "particularly preferred." This also includes features designated as "embodiments" of varying preferred features.

[0017] (a) Radically polymerizable compound

[0018] The adhesive film according to the invention comprises at least one radically polymerizable compound.

[0019] The term “polymerizable” refers here, in accordance with expert understanding, to the ability of these compounds to undergo a polymerization reaction, possibly after suitable activation.

[0020] In accordance with expert understanding, the radically polymerizable compound should stand for a compound that is capable of undergoing a radical reaction, in particular a radical chain polymerization.

[0021] Preferably the radically polymerizable compound (a) is selected from the group consisting of radically polymerizable monomers, radically polymerizable oligomers and radically polymerizable polymers.

[0022] According to particularly advantageous embodiments, radically polymerizable monomers and / or radically polymerizable polymers are preferred.

[0023] Preferably, the radically polymerizable monomer or oligomer is selected from the group consisting of acrylic acid esters, methacrylic acid esters, vinyl compounds, compounds with olefinic carbon-carbon double bonds, crosslinking radically polymerizable compounds such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates and higher functional methacrylates.

[0024] Here, "higher functional" acrylates or methacrylates are understood to be (meth)acrylates with four or more (meth)acrylate functional groups.

[0025] Particularly preferably, the radically polymerizable compound (a) has at least one acrylate or methacrylate functional group. This applies to radically polymerizable monomers, oligomers, and polymers. Oligomeric substances with acrylate or methacrylate functional groups are known to those skilled in the art and are also referred to as reactive resins. Here, too, the functionalization can be present singly or multiply within the molecule. According to advantageous embodiments, these are used in a mixture with at least one reactive monomer.

[0026] Preferred monomers for high bond strength are acrylic and / or methacrylic esters in which the alcohol portion of the ester contains aromatic structural elements, heteroatoms, or functional groups. Urethane groups, urea groups, oxygen or nitrogen heterocycles, ether groups, ester groups, acid functional groups, and / or hydroxyl functional groups are preferred. For good wet-heat resistance, acrylic and / or methacrylic esters in which the alcohol portion of the ester is a fatty alcohol are also preferred. Furthermore, for high crosslinking density, crosslinking monomers, and thus especially monomers with two or more (meth)acrylate functional groups, are preferred.

[0027] Examples of preferred monomers are 2-phenoxyethyl acrylate (CAS No.: 48145-04-6), 2-phenoxyethyl methacrylate (CAS No.: 10595-06-9), 2-hydroxy-3-phenoxypropyl acrylate (CAS No.: 16969-10-1), 2-hydroxy-3-phenoxypropyl methacrylate (CAS No.: 16926-87-7), 2-[2-(methacryloyloxy)ethoxycarbonyl]benzoic acid (CAS No.: 27697-00-3), 2-[[(phenylamino)-carbonyl]oxy]ethyl methacrylate (CAS No.: 51727-47-0), 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy- 5-methylphenyl)methyl]-4-methylphenylprop-2-enoate (CAS No.: 61167-58-6), (5-Ethyl-1,3-dioxan-5-yl)methyl acrylate (CAS No. 66492-51-1), (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate (CAS No.: 13818-44-5), di(ethylene glycol)-2-ethylhexyl ether acrylate (CAS no.: 117646-83-0), (2,2-dimethyl-1,3-dioxolan-4-yl)methylprop-2-enoate (CAS no.: 13188-82-4), 2-succinic acid mono-[2-(acryloyloxy)-ethyl ester] (CAS No.: 50940-49-3), 2-succinic acid mono-[2-(meth-acryloyloxy)ethyl ester] (CAS no.: 20882-04-6), (2,2-Pentamethylene-1,3-oxazolidyl-3)ethyl methacrylate (CAS No.: 4203-89-8), 2-Hydroxy-3-(prop-2-enoyloxy)propyl-2-methyl-2-propyl hexanoate (CAS No.: 444649-70-1), 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate (CAS No.: 63225-53-6), stearyl acrylate (CAS No.: 4813-57-4), stearyl methacrylate (CAS No.: 32360-05-7), and the crosslinking reactive monomers diurethane dimethacrylate (isomer mixture) (CAS No.: 72869-86-4), bisphenol A-diglycidyl methacrylate (BIS-GMA, CAS No.: 1565-94-2), Bisphenol A dimethacrylate (BIS-DMA, CAS No.: 3253-39-2), Ethylene glycol diacrylate (CAS No.: 2274-11-5), Ethylene glycol dimethacrylate (CAS No.: 97-90-5), Trimethyloylpropane propoxylate triacrylate (CAS No.: 53879-54-2), Trimethyloylpropane triacrylate (CAS No.: 15625-89-5) and / or Di(trimethylolpropane)tetraacrylate (CAS No.: 94108-97-1).

[0028] Particularly preferred are 2-Hydroxy-3-phenoxy-propyl acrylate (CAS No.: 16969-10-1), 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate and diurethane dimethacrylate.

[0029] According to particularly advantageous embodiments of the invention, (a) the radically polymerizable compound 2-hydroxy-3-phenoxy-propyl acrylate is included.

[0030] Radically polymerizable oligomers, in particular in contrast to polymers, are understood by those skilled in the art to be compounds that are radically polymerizable with a weight average of the molecular weight distribution M. w of less than 35000 g / mol, in particular less than 15000 g / mol, in particular less than 10000 g / mol, and in particular within the scope of the present invention, so-called urethane acrylates.

[0031] These include aliphatic and aromatic polyester urethane (meth)acrylates, polyether urethane (meth)acrylates, polybutadiene urethane (meth)acrylates, and silicone urethane (meth)acrylates. They are available, for example, from Miwon, Bomar, and Allnex, such as the aliphatic polyester urethane MIRAMER SC2565 with a molecular weight of 5200 g / mol from Miwon, or the aliphatic urethane acrylates known under the trade names EBECRYL® 8402, EBECRYL® 4858, or EBECRYL® 8809 from Allnex, or the hydrophobic urethane acrylate BRC 843 from Bomar.

[0032] Other examples of radically polymerizable oligomers are aliphatic and aromatic polyester (meth)acrylates, such as the polyester acrylate EBECRYL® 5850 from Allnex, polyether (meth)acrylates, epoxy (meth)acrylates, dendritic (meth)acrylates and polycarbonate (meth)acrylates.

[0033] Other options include acrylated oligoesters, for example based on caprolactones, such as the commercially available hydroxyethylcaprolactone acrylate (HECLA; CAS No.: 110489-05-9).

[0034] The functionality of the polymerizable oligomers is preferred, i.e., the number of radically polymerizable groups per molecule is 1 to 20, usually 2 to 15, mainly 2 to 6. The dynamic viscosity, determined according to DIN 53019-1 from 2008, at 25°C is preferably greater than 1 Pa·s, but particularly preferably significantly greater than 10 Pa·s. Oligomers with dynamic viscosities at 25°C greater than 20 Pa·s, preferably greater than 30 Pa·s, are particularly suitable as components for the production of good pressure-sensitive adhesives with sufficient cohesion. Within the scope of the present invention, the dynamic viscosity is determined according to DIN 53019-1 from 2008 at 25°C with a shear rate of 1 s⁻¹. 1 certainly.

[0035] According to particularly advantageous embodiments of the invention, the (a) radically polymerizable compound includes a radically polymerizable polymer. According to preferred embodiments, the radically polymerizable polymer is selected from the group consisting of acrylate-functionalized polyurethanes, methacrylate-functionalized polyurethanes, and acrylate- and methacrylate-functionalized polyurethanes.

[0036] This polyurethane can simultaneously act as a film-forming agent in the reactive adhesive film according to the invention.

[0037] It thus gives the reactive adhesive film according to the invention its film form. The acrylate- or methacrylate-functionalized polyurethane remains tacky before light curing. Tacky viscoelastic adhesive films are defined as those whose cured, dry film is permanently tacky and remains adhesive at room temperature. Pressure adhesion occurs immediately on almost all substrates with slight contact pressure. Slight contact pressure here refers to a pressure greater than 0 bar, applied for a duration greater than 0 seconds.

[0038] Furthermore, the acrylate- and / or methacrylate-functionalized polyurethane is reactive, stemming from the acrylate and / or methacrylate functional group. Acrylate and methacrylate groups are known to undergo radical reactions, which can be triggered, for example, by radical initiators.

[0039] In a preferred embodiment, the acrylate and / or methacrylate functionalized polyurethane is the chemical reaction product of a1) at least one diol and / or polyol, a2) at least one acrylate and / or methacrylate functionalized diol and / or polyol, and a3) at least one di- and / or poly-isocyanate.

[0040] In principle, all known di- or multi-hydroxyl-functionalized substances are eligible as diols / polyols, in particular all polyester diols / polyols, including all polycaprolactone diols / polyols, all polyester carbonate diols / polyols, all polyether diols / polyols, and all polybutadiene diols / polyols, as well as substances derived from or derived from these substances. Furthermore, so-called chain extenders and / or crosslinkers are also eligible, which here are understood to be di- or multi-hydroxyl-functionalized substances that are not poly compounds.

[0041] Polyester diols that can be used according to the invention: APolyols are polyesters with terminally bonded hydroxyl groups.

[0042] Polyester diols have two terminally bonded hydroxyl groups and are therefore difunctional. In polyester polyols, the number of terminally bonded hydroxyl groups is not clearly defined. There can be two or more hydroxyl groups per molecule. In this document, polyester polyols are defined as those with more than two hydroxyl groups per molecule. Polyester diols / polyols usable according to the invention are generally obtained by polycondensation from diols / polyols and di- / -polycarboxylic acids, or, in the case of polycaprolactone polyols, by ring-opening polymerization from e-caprolactone and a di- or polyfunctional starter molecule.

[0043] Polyester carbonate diols are doubly hydroxyl-functionalized polyesters whose molecular chain also contains at least one carbonic acid ester group. They can be obtained, for example, by the poly-reaction of a diol, a dicarboxylic acid, and dimethyl carbonate (DMC) or diphenyl carbonate (DPC). The number of terminally bonded hydroxyl groups in polyester carbonate polyols is not clearly defined. There can be two or more hydroxyl groups per molecule. In this document, polyester carbonate polyols are defined as those with more than two hydroxyl groups per molecule.

[0044] Polyether diols usable according to the invention: Polyols are polyethers with terminally bonded hydroxyl groups. Polyether diols have two terminally bonded hydroxyl groups and are therefore difunctional. The number of terminally bonded hydroxyl groups in polyether polyols is not clearly defined. There can be two or more hydroxyl groups per molecule. In this document, polyether polyols are understood to be those with more than two hydroxyl groups per molecule. Polyether diols / polyols usable according to the invention are primarily produced from ethylene oxide, propylene oxide, or tetrahydrofuran by ring-opening polymerization or copolymerization using a starter molecule that determines the functionality.

[0045] Polybutadiene diols are doubly hydroxyl-functionalized polybutadienes produced from butadiene via an anionic polymerization process. Well-known commercial products include, for example, the KrasolO types from Cray Valley.

[0046] Polybutadiene polyols can contain two or more hydroxyl groups per molecule. In this document, polybutadiene polyols are defined as those with more than two hydroxyl groups per molecule. They are produced from butadiene via a radical polymerization process. Well-known commercial products include, for example, the Poly bd® types from Cray Valley.

[0047] Examples of chain extenders are 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, propylene glycol, dipropylene glycol, 1,4-cyclohexanediethanol or 2-eth-1,3-hexanediol.

[0048] Examples of crosslinking agents are glycerin, trimethylolpropane, or 1,2,4-butanetriol.

[0049] According to particularly advantageous embodiments of the invention, the a1) is at least one diol and / or polyol selected from the group consisting of polyester diols, polyester polyols, polyester carbonate diols and polyester carbonate polyols, wherein polyester diols and / or polyester carbonate diols are again particularly preferred.

[0050] The a2) at least one acrylate- and / or methacrylate-functionalized diol and / or acrylate- and / or methacrylate-functionalized polyol is, according to preferred embodiments of the invention, a diolic or polyolic alkyl(meth)acrylate, wherein the alkyl group is linear or branched and the alkyl group has three to twenty, preferably three to ten, again preferably three to six, in particular and for example three or five carbon atoms.

[0051] The term “diolic alkyl(meth)acrylate” refers to an alkyl(meth)acrylate compound that has two hydroxyl groups on the alkyl residue.

[0052] The term “polyolic alkyl(meth)acrylate” refers to an alkyl(meth)acrylate compound that has more than two hydroxyl groups, for example three hydroxyl groups, on the alkyl residue.

[0053] The problem underlying the invention is particularly well solved with such acrylate and / or methacrylate-functionalized diols and / or acrylate and / or methacrylate-functionalized polyols.

[0054] The a2) at least one acrylate and / or methacrylate-functionalized diol and / or acrylate and / or methacrylate-functionalized polyol is selected according to particularly preferred embodiments of the invention from the group consisting of 2,3-dihydroxypropyl acrylate (CAS No.: 10095-20-2), 2,3-dihydroxypropyl methacrylate (CAS No.: 5919-74-4), 1,3-dihydroxy-2-propanyl acrylate (CAS No.: 119051-91-1), 3-hydroxy-2,3-bis(hydroxymethyl)propyl acrylate (CAS No.: 55919-77-2).

[0055] In turn, a2) at least one acrylate and / or methacrylate functionalized diol is particularly preferred, wherein this in turn is particularly preferably selected from the group consisting of 2,3-dihydroxypropyl acrylate and 2,3-dihydroxypropyl methacrylate.

[0056] Particularly preferred is a light-curing, reactive, pressure-sensitive adhesive film, wherein the at least one acrylate and / or methacrylate-functionalized polyurethane comprises the chemical reaction product of a1) at least one diol and / or polyol, a2) 2,3-dihydroxypropyl acrylate and / or 2,3-dihydroxypropyl methacrylate and a3) at least one di- and / or poly-isocyanate.

[0057] a3) Di- and / or poly-isocyanates that can be used according to the invention are all known aliphatic and / or aromatic di-isocyanates and / or poly-isocyanates. Di-isocyanates have two isocyanate groups per molecule and are therefore difunctional. Poly-isocyanates have two or more isocyanate groups per molecule. In this document, poly-isocyanates are understood to be those with more than two isocyanate groups per molecule.

[0058] Examples of suitable di- and / or poly-isocyanates are 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane (isophorone diisocyanate, IPDI), hexane-1,6-diisocyanate (hexamethylene diisocyanate, HDI), dicyclohexylmethane-4,4'-diisocyanate (H12MDI), toluene diisocyanate, diphenylmethane-4,4'-diisocyanate and / or m-tetramethylxylene diisocyanate (TMXDI), mixtures of the aforementioned isocyanates or chemically derived isocyanates, for example dimerized, trimerized or polymerized types containing, for example, urea, uretdione or isocyanurate groups.

[0059] According to advantageous embodiments, a3) the diisocyanate hexane-1,6-diisocyanate (hexamethylene diisocyanate, HDI) is used.

[0060] To accelerate the reaction of the diols / polyols with the di- / poly isocyanates, one or more catalysts known to those skilled in the art, such as tertiary amines, bismuth or organotin compounds, to name just a few, can be used.

[0061] Bismuth and carbon-containing catalysts can be used very advantageously, preferably a bismuth carboxylate or a bismuth carboxylate derivative, in particular bismuth trisneodecanoate, CAS No.: 34364-26-6.

[0062] The catalyst concentration is adjusted to the diols / polyols and di- / poly-isocyanates used. Generally, it ranges between 0.01 wt% and 0.5 wt% of the polyurethane to be produced.

[0063] The acrylate- or methacrylate-functionalized polyurethane is preferably thermoplastic.

[0064] Therefore, difunctional starting materials, i.e. diols and diisocyanates, are preferably used.

[0065] Suitable polyols are particularly triols, although higher polyols are preferably avoided.

[0066] This applies to the diols and polyols of groups a1) and a2). When trioiens are used in groups a1) and a2), care should be taken to ensure that no gelation occurs during polyurethane production. This means that the degree of branching relative to the length of the polymer chains produced should not be so high that cross-linking occurs during polyurethane production. The degree of branching is adjusted so that no cross-linked structures form. To prevent cross-linked structures, the so-called gel point must not be exceeded. As is known to those skilled in the art, the theoretical gel point can be calculated using P.J. Flory's gel point equation or a formula derived from the Flory equation for estimating the gelation NCO / OH ratio in polyurethane formation reactions from diols and trioiens with diisocyanates.

[0067] The derived formula is:

[0068] 1

[0069] NCO

[0070] OH 1

[0071] Gelation 1 + -

[0072] (Diol-OH) +1

[0073] (Triol-OH)

[0074] In this formula, Diol-OH refers to the total number of hydroxyl groups involved in the polyurethane formation reaction that originate from diols. This includes chain extenders as well as acrylate- and / or methacrylate-functionalized diols. Triol-OH refers to the total number of hydroxyl groups involved in the polyurethane formation reaction that are bound to triols. This includes crosslinkers as well as acrylate- and / or methacrylate-functionalized triols.

[0075] The NCO / OH ratio is preferably 0.5 to 1.

[0076] The number-averaged mean hydroxyl functionality refers to the average number of hydroxyl groups per molecule of a polymeric diol, such as polyester diols, or polymeric polyol, such as polyester polyol. In this document, it is related to the number-averaged mean molecular weight of the respective diol or polyol and calculated using the following formula: f = M n [g / mol] x OHZ [mmol OH / kg] / 10 6 f is the number-averaged, mean hydroxyl functionality. M n is the number-averaged mean molecular weight of the respective diol or polyol in the unit [g / mol] and OHZ is the hydroxyl number of the diol or polyol in the unit [mmol OH / kg].

[0077] The hydroxyl number is a measure of the content of hydroxyl groups in a diol or polyol.

[0078] The hydroxyl value is determined according to DIN 53240. According to this method, the hydroxyl value (OHZ) is expressed in the unit [mg KOH / g]. It corresponds to the amount of KOH in [mg] that is equivalent to the amount of acetic acid bound during the acetylation of 1 g of diol or polyol. For the purpose of simplifying formulation calculations, the hydroxyl value is converted to the unit [mmol OH / kg] in this document.

[0079] This is done according to the following formula:

[0080] OHZ [mmol OH / kg] = OHZ[mg KOH / g] x1000 / 56.1.

[0081] 56, 1 is the molar mass of KOH.

[0082] If the gelling NCO / OH ratio is reached or exceeded, the formation of cross-linked structures, i.e., the onset of gelation, must be expected. The formula derived from the Flory equation provides only an approximate, but usually sufficient, indication of the NCO / OH ratio at which actual gelation occurs.

[0083] When using polyisocyanates with an isocyanate functionality of three in the production of polyurethane, analogous considerations apply to avoid gelation. For this reason, the simultaneous use of triols and triisocyanates should also be avoided. Functionalities greater than three should likewise be avoided for this reason.

[0084] To achieve pressure-sensitive tack, the NCO / OH ratio is preferably adjusted to a slight deficiency of NCO groups, even when only diols and diisocyanates are used. Preferred NCO / OH ratios in this case are in the range of 0.9 to 1.0, particularly preferably 0.9 to 0.99. If a trifunctional compound is also used, the required NCO / OH ratio is determined by the formula above. The NCO / OH ratio is defined as the ratio of the total number of isocyanate groups used in the polyurethane formation reaction to the total number of hydroxyl groups used in the polyurethane formation reaction, i.e., the molar ratio of isocyanate groups to hydroxyl groups, regardless of whether the molecules of the respective substances actually react completely or only partially. To achieve pressure-sensitive tack, the number-averaged mean molar mass M is also used. nof a1) at least one diol and / or polyol preferably selected such that it lies between inclusive 400 g / mol and inclusive 6000 g / mol, preferably between inclusive 1000 g / mol and inclusive 4000 g / mol.

[0085] Furthermore, the ratio of the number of hydroxyl groups originating from a1) the at least one diol and / or polyol to the number of hydroxyl groups originating from a2) the at least one acrylate and / or methacrylate-functionalized diol or polyol, i.e., the molar ratio of the corresponding hydroxyl groups, is preferably chosen to be between 95 to 5 and 5 to 95, preferably between 80 to 20 and 20 to 80.

[0086] The chemical reaction to polyurethane can take place solvent-free – i.e., in the melt – in an organic solvent, or in an aqueous dispersion. In the latter two cases, the polyurethane is dissolved in an organic solvent or dispersed in water. To improve the dispersion of the polyurethane in water, dimethylolpropionic acid or a similarly structured substance is preferably used, as is known in the prior art.

[0087] As is also known in the prior art, the reaction to build up the corresponding prepolymer can easily be carried out in such a way that only the OH groups react, while the carboxy function remains uninvolved.

[0088] Generally, polyurethanes and their production are familiar to experts.

[0089] According to particularly advantageous embodiments of the invention, at least one acrylate and / or methacrylate-functionalized polyurethane is included as (a) a radically polymerizable compound.

[0090] The aforementioned possibilities or embodiments for the radically polymerizable compound can also be used in combination, i.e., in a mixture.

[0091] The proportion of the at least one radically polymerizable compound(s) is preferably in the range of 10 to 99 wt%, particularly preferably 20 to 99 wt%, based on the total weight of the components of the reactive adhesive film according to the invention.

[0092] Preferably, 30 to 99 wt.% of the at least one radically polymerizable compound is used, based on the total mixture of components of the reactive adhesive film.

[0093] In the event that more than one radically polymerizable compound is used, the quantities refer to the total quantity of (a) radically polymerizable compounds.

[0094] The total mixture of the components of the reactive adhesive film according to the invention, and thus the overall composition of the adhesive film, represents, within the scope of the present invention, the total quantity of the (a) at least one radically polymerizable compound, (b) the at least one radical initiator, (c) the at least one photoredox catalyst, (d) the at least one carbon black, and, if present, (e) the at least one additional film-forming polymer, as well as (f) any further optional components, namely further additives and / or auxiliary substances, which is obtained as a sum in weight percent (wt%). Solvents or water are used only for the preparation and are not included in this consideration of the total mixture of components of the reactive adhesive film according to the invention. This also applies to solvents that may already be contained in the commercially available raw materials.

[0095] (b) Radical initiator

[0096] The adhesive film according to the invention comprises (b) at least one radical initiator.

[0097] As used here, the term radical initiator refers to a radical-forming substance that can initiate a polymerization reaction or crosslinking radical reaction of the adhesive film. The radical initiator participates in the reaction only to a very small extent and consequently does not form a polymer component that determines the properties of the bond.

[0098] In the present invention, at least one radical initiator is added to the reactive adhesive film according to the invention. The radical initiator is preferably selected such that it does not trigger polymerization in the mixture with the at least one radically polymerizable compound at temperatures up to 90°C, even when the mixture is irradiated with UV or blue light. This applies as long as no photoredox catalyst or other activating substance is added to the mixture.

[0099] The radical initiator is explicitly not a photoinitiator. It does not decompose upon irradiation with visible or UV light. This also applies to the use of more than one initiator, especially radical initiator: none of the compounds mentioned are photoinitiators.

[0100] The radical initiator refers to a compound that, in the prior art, is usually thermally excited and thereby decomposes into reactive, radical fission products.

[0101] All known radical initiators can be used. Preferred radical initiators are peroxides, especially hydroperoxides.

[0102] In a particularly preferred embodiment according to the invention, the at least one radical initiator is an organic peroxide, such as peroxycarboxylic acids and hydroperoxides. 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 diisopropylbenzene hydroperoxide in diisopropylbenzene, available under the trade name DIHP® INEOS (INEOS Solvents GmbH, Herne, Germany). α,α-Dimethylbenzyl hydroperoxide, which is 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), tert-butyl hydroperoxide (CAS No. 75-91-2) or 1,1,3,3-tetramethylbutyl hydroperoxide (CAS No. 5809-08-5) can also be used.

[0103] The proportion of at least one radical initiator, or of radical initiators in the case of two or more, is preferably in the range of 0.1 to 10 wt.%, particularly preferably 0.5 to 9 wt.%, based on the total mixture of the components of the reactive adhesive film according to the invention. Most preferably, 0.5 to 8 wt.%, and again more preferably 0.5 to 5 wt.%, of at least one radical initiator, based on the total weight of the reactive adhesive film according to the invention, is used.

[0104] (c) Photoredox catalyst

[0105] The adhesive film according to the invention comprises (c) at least one photoredox catalyst.

[0106] As used here, the term photoredox catalyst refers to a light- or UV-light-sensitive compound that, when excited by light or 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 upon irradiation with light or UV light, but is merely brought to an excited state, which is generally relatively long-lived and from which redox processes can be initiated or mediated. Preferably, the photoredox catalyst, when mixed with at least one radically polymerizable compound, does not induce polymerization at temperatures up to 90 °C, even when the mixture is irradiated with UV or blue light. This holds true as long as no radical initiator or other initiating substance is added to the mixture.The photoredox catalyst is therefore neither an initiator nor a photoinitiator. When irradiated with UV or blue light, it merely activates the initiator, which then triggers the polymerization. This also applies if two or more photoredox catalysts are used. Again, none of the photoredox catalysts is an initiator.

[0107] At least one photoredox catalyst is preferably selected from complex compounds with ruthenium or iridium as the central atom.

[0108] Preferred are polypyridyl complexes of ruthenium or iridium, such as Ru(bpm)3 2+ (e.g. Tris(2,2'-bipyrimide)ruthenium(II) dichloride), Ru(bpz)3 2+ (e.g. Tris(2,2'-bipyrazine)ruthenium bis(hexafluorophosphate)), Ru(bpy)3 2+ (e.g. Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate), Ru(phen)3 2+ (e.g. Dichlorotris(1,10-phenanthroline)ruthenium(II)chloride), lr[dF(CF3)ppy]2(dtbbpy) +(e.g. [4,4'-ß / s(1 , 1 -dimethylethyl)-2,2'-bipyridine-A / 1 , / 1 '] bis[3,5-difluoro- 2-[5-(trifluoromethyl)-2-pyridinyl-A / ]phenyl-C]lridium(III) hexafluorophosphate), lr(ppy)s (tris(2-phenylpyridinato)iridium(III)), lr(ppy)2(dtbbpy) + (e.g. [Ir(dtbbpy)(ppy)2] [PF6]), lr(Fppy)3(Tris[2- (2,4-difluorophenyl)pyridine]iridium(l 11)) or fac-lr(ppy)3 (fac-Tris(2-phenylpyridine)iridium(l 11)).

[0109] In a preferred embodiment of the invention, the photoredox catalyst is a complex with ruthenium as the central atom and bipyridine or a singly or multiply substituted bipyridine derivative as a ligand. In a further preferred embodiment of the invention, the photoredox catalyst is a complex with iridium as the central atom and phenylpyridine or a singly or multiply substituted phenylpyridine derivative as a ligand.

[0110] A light-curing, reactive, adhesive film according to the invention is therefore preferred, wherein the at least one photoredox catalyst (c)

[0111] Ruthenium as the central atom and bipyridine or a singly or multiply substituted bipyridine derivative as ligands, or

[0112] Iridium as the central atom and phenylpyridine or a simply or multiply substituted phenylpyridine derivative as ligands.

[0113] According to particularly preferred embodiments of the invention, the photoredox catalyst is selected from: i. [Tris(2,2'-bipyridyl)ruthenium(11)] 2+ , [Ru(bpy)3] 2+ - Formula (1a):

[0114] Tris[2-(2,4-difluorophenyl)pyridine]iridium(lll), lr(Fppy)3; CAS No.: 387859-70-3 - Formula

[0115] (lb):

[0116] Tris(2-phenylpyridinato)iridium(lll), lr(ppy)3; CAS No.: 94928-86-6 - Formula (Ic):

[0117] The preferred counterion of the cation of formula (1a) is chloride. The corresponding commercially available product contains water of crystallization.

[0118] The particularly preferred embodiment of the photoredox catalyst of formula (1a) is therefore Tris(2,2'-bipyridyl)ruthenium(11) chloride hexahydrate, (CAS No.: 50525-27-4), available from CHEMOS GmbH & Co. KG (Altdorf, Germany, http: / / www.chemos.de).

[0119] The photoredox catalyst with formula (Ic) is also available from CHEMOS GmbH & Co. KG. The photoredox catalyst with formula (Ib) is available from Strem (Europe) (Bischheim, France, http: / / www.strem.com).

[0120] The proportion of the photoredox catalyst(s) in the case of two or more is preferably in the range of up to 1 wt.%, particularly preferably up to 0.75 wt.%, most preferably up to 0.5 wt.%, wherein the minimum amount is advantageously 0.01 wt.%, preferably at least 0.05 wt.%, in each case based on the total weight of the reactive adhesive film according to the invention.

[0121] Preferably, the light-curing, reactive, adhesive film according to the invention contains no further activating, initiating or influencing components than those mentioned in this document, in particular no photoinitiators.

[0122] (d) soot

[0123] The adhesive film according to the invention comprises (d) at least one carbon black.

[0124] As used here, the term carbon black refers to industrial carbon black (CAS No.: 1333-86-4). It is a modification of carbon with a high surface area to volume ratio. In the prior art, carbon black is primarily used as a filler and as a black pigment. Depending on the manufacturing process and process parameters, different types of carbon black are distinguished. These include channel black, gas black, furnace black, lamp black, thermal black, and acetylene black.

[0125] To differentiate between the types of soot and the various grades or commercial products within a type of soot, parameters such as the average particle size, the BET surface area or the oil absorption number (OAN) are used.

[0126] According to the invention, all types of carbon black known in the prior art can be used. Preferably, at least one furnace carbon black is used. The preferred BET surface area is in the range of 20 to 400 m². 2 / g, determined according to ASTM D6556. The preferred OAN is in the range of 40 to 160 ml / 100g, determined according to ASTM D2414. Printex® brand carbon black, available from Orion Engineered Carbons GmbH (Frankfurt am Main, Germany), was used in the examples.

[0127] The proportion of carbon black(s) in the case of two or more carbon blacks is preferably in the range of 0.01 to 10 wt.%, particularly preferably 0.02 to 5 wt.%, based on the total weight of the reactive adhesive film according to the invention. Most preferably, 0.05 to 5 wt.% carbon black, based on the total weight of the reactive adhesive film according to the invention, is used.

[0128] (e) Optional film-forming polymer

[0129] According to advantageous embodiments, the reactive adhesive film according to the invention comprises, in addition to the above-mentioned components (a) to (d), a film-forming polymer, particularly when the combination of components (a) to (d) does not already result in the formation of an adhesive film. The film-forming polymer is thus intended to give the reactive adhesive film according to the invention its film shape and to stabilize this shape.

[0130] The optionally included film-forming polymer (e) is in particular not a radically polymerizable compound and is therefore, within the scope of the present invention, a “non-reactive film-forming polymer”.

[0131] Such a non-reactive film-forming polymer does not, in particular, carry any free reactive functional groups, especially no (meth)acrylate functionalities, like the (meth)acrylate-functionalized polyurethane described in (a). The (e) non-reactive film-forming polymer is therefore free of reactive functional groups, especially free of (meth)acrylate functionalities.

[0132] Suitable non-reactive film-forming polymers for use in the present invention are thermoplastic polymers, such as polyurethanes, polyesters or copolyesters, polyamides or copolyamides, polyacrylic acid esters, acrylic acid / acrylic acid ester copolymers (such as a copolymer of n-butyl acrylate, ethyl acrylate, and acrylic acid), polymethacrylic acid esters, methacrylic acid / methacrylic acid ester copolymers, polyvinyl acetate, or ethylene-vinyl acetate copolymers. Chemically or physically crosslinked, but non-crosslinkable, 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 film-forming polymers.

[0133] Thermoplastic polymers with a crystalline melting point of less than 100 °C and / or a softening point of less than 100 °C are preferred. In this context, the term softening point refers to the temperature at which the thermoplastic granules bond to themselves. If the film-forming polymer is a semicrystalline thermoplastic polymer, then, in addition to its softening point (which is related to the melting of the crystals), it very preferably has a glass transition temperature of at most 25 °C, preferably at most 0 °C.

[0134] According to advantageous embodiments of the invention, a thermoplastic, non-reactive polyurethane is used as an additional film-forming polymer (e).

[0135] Commercially available thermoplastic polyurethanes include, for example, Desmocoll® 530 / 1 and Desmocoll® 540 / 3, as well as Desmomelt® 530 from Covestro AG (Leverkusen, Germany), or IROSTIC® S-6558-06 and IROSTIC® S 8612 from Huntsman (Huntsman Holland BV, Botlek-Rotterdam, Netherlands), or alternative variants from these product lines. Other examples include the Elastollan® product line from BASF (Ludwigshafen, Germany) and Pearlbond from Lubrizol (Lubrizol Advanced Materials Europe BVBA, Brussels, Belgium). Preferably, the thermoplastic polyurethane has a softening temperature of less than 100 °C, particularly less than 80 °C. Preferred examples of such thermoplastic polyurethanes are Desmomelt® 530 and IROSTIC® S-6558-06. Desmomelt® 530 is a hydroxyl-terminated, largely linear, thermoplastic, highly crystallizing polyurethane elastomer.According to the manufacturer, IROSTIC® S-6558-06 is a linear thermoplastic polyurethane for solvent-based adhesives. Its characteristics, according to the manufacturer, are: very low crystallization rate, long open time, and very low activation temperature.

[0136] Thermoplastic polyurethanes with a very low crystallization rate are particularly preferred. Thermoplastic polyurethanes are especially preferred if their DSC diagram shows no signal (peak) for a crystalline melting point in the second heating curve within the temperature range between -140 °C and +250 °C. In a preferred embodiment, the light-curing, reactive, pressure-sensitive adhesive film according to the invention is characterized in that the film-forming polymer (e) is a thermoplastic polyurethane whose DSC diagram shows no signal for a crystalline melting point in the second heating curve within the temperature range between -140 °C and +250 °C. Heating, cooling, and reheating are each carried out at a heating rate of 10 Kelvin per minute (with a 10 mg sample quantity). The abbreviation DSC stands for the well-known thermoanalytical method "Differential Scanning Calorimetry" according to DIN EN ISO 11357-1 to -8.The method for determining the melting and crystallization temperature as well as the melting and crystallization enthalpy is specified in DIN EN ISO 11357-3.

[0137] Therefore, in a particularly preferred embodiment according to the invention, IROSTIC® S-6558-06 is used as a non-reactive film-forming polymer, since it has a very low crystallization rate and shows no signal (peak) of a crystalline melting point in the second heating curve of the DSC diagram in the temperature range between minus 140 °C and plus 250 °C.

[0138] The proportion of the film-forming polymer(s) in the case of two or more is preferably in the range of 10 to 85 wt.%, particularly preferably 20 to 80 wt.%, based on the total weight of the reactive adhesive film according to the invention. Most preferably, 30 to 60 wt.% of the film-forming polymer(s)(e), based on the total weight of the reactive adhesive film according to the invention, is used.

[0139] Other components of the reactive adhesive film

[0140] According to advantageous embodiments of the invention, the reactive adhesive film according to the invention contains no further additives and / or auxiliary materials, i.e. 0 wt.% of further additives and / or auxiliary materials.

[0141] According to further advantageous embodiments of the invention, the reactive adhesive film according to the invention contains further additives and / or auxiliary materials.

[0142] The proportion of further additives and / or auxiliary materials is preferably in the range of 0.5 to 30 wt.%, preferably 0.5 to 25 wt.%, and most preferably 0.5 to 20 wt.%, based on the total weight of the reactive adhesive film according to the invention.

[0143] Other additives and / or auxiliary materials include, for example, additional fillers besides the carbon blacks described, dyes, nucleating agents, rheological additives (for example, fumed silica), blowing agents, adhesive-enhancing additives (adhesion promoters, in particular silanes and tackifier resins), compounding agents, plasticizers, and / or aging, light, and UV protectants, for example, in the form of primary and secondary antioxidants. According to advantageous embodiments of the invention, the adhesive film according to the invention contains fumed silica, in particular hydrophobized fumed silica, CAS No. 7631-86-9, which is available, for example, under the trade name Aerosil® R202 from Evonik Operations GmbH.

[0144] According to preferred embodiments, the amount of pyrogenic silica is 1 to 8 wt.%, particularly preferably 3 to 5 wt.%.

[0145] According to advantageous embodiments of the invention, the adhesive film according to the invention contains titanium dioxide.

[0146] Preferably, titanium dioxide pigment powder (CAS No.: 13463-67-7) can be used, either titanium dioxide with a rutile structure or, particularly preferably, titanium dioxide with an anatase structure. The latter is known in the prior art for its photocatalytic effect.

[0147] An example of a suitable titanium dioxide pigment powder with a rutile structure is Tiona® 595 from Tronox (www.tronox.com). A suitable titanium dioxide pigment powder with an anatase structure is, for example, Kronos® 1002 from Kronos International Inc. (Leverkusen, Germany).

[0148] According to preferred embodiments, the amount of titanium dioxide is 0.5 to 2 wt.%, particularly preferably 0.7 to 1.3 wt.%.

[0149] A further advantageous component of the reactive adhesive film according to the invention is a polymer obtained by radical polymerization of monomers containing carbon-carbon double bonds, characterized in that these monomers comprise N-vinyl compounds. Such a polymer is known from EP4159775B1. According to particularly preferred embodiments, the adhesive film according to the invention contains poly(N-vinylcaprolactam).

[0150] This results in particularly good properties, especially high bonding strengths, high storage stability and high hydrolysis resistance, which is particularly noticeable after storage under humid-warm conditions.

[0151] According to preferred embodiments, the amount of poly(N-vinylcaprolactam) is 5 to 25 wt.%, particularly preferably 10 to 20 wt.%.

[0152] According to advantageous embodiments of the invention, two or more additives and / or auxiliary materials are used as component (f).

[0153] According to advantageous embodiments of the invention, the adhesive film (f) contains a combination of pyrogenic silica and poly(N-vinylcaprolactam).

[0154] According to further advantageous embodiments of the invention, the adhesive film (f) contains a combination of pyrogenic silica and poly(N-vinylcaprolactam) and titanium dioxide.

[0155] The above quantity limits, including all preferential treatment levels, apply to all embodiments and combinations.

[0156] In the case of additives and / or excipients (f), the total amounts are always meant in the case of two or more of the substances mentioned, unless otherwise stated.

[0157] Reactive adhesive film

[0158] The light-curing, reactive, pressure-sensitive adhesive film according to the invention is in the form of a film. The term "film" is familiar to those skilled in the art in connection with adhesives. As used herein, the term "adhesive film" (or also adhesive layer, adhesive film) is intended to encompass a complete or incomplete application of the light-curing, reactive adhesive mixture, as described below. For example, a spot 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.

[0159] The light-curing, reactive, adhesive film according to the invention comprises, according to preferred embodiments, the following:

[0160] (a) 10 to 99 wt.%, preferably 20 to 99 wt.%, particularly preferably 30 to 99 wt.%, of at least one radically polymerizable compound, and

[0161] (b) 0.1 to 10.0 wt.%, preferably 0.5 to 9 wt.%, particularly preferably 0.5 to 8 wt.%, again preferably 0.5 to 5 wt.%, of at least one radical initiator, and

[0162] (c) 0.01 to 1.0 wt.%, preferably 0.01 to 0.75 wt.%, particularly preferably 0.01 to 0.5 wt.%, again preferably at least 0.05 wt.%, of at least one photoredox catalyst, and

[0163] (d) 0.01 to 10 wt.%, preferably 0.02 to 5 wt.%, particularly preferably 0.05 to 5 wt.% of at least one carbon black.

[0164] Preferably, the following are (a) at least one radically polymerizable monomer, preferably 2-hydroxy-3-phenoxypropyl acrylate, and / or at least one radically polymerizable polymer, preferably at least one acrylate- and / or methacrylate-functionalized polyurethane; and (b) at least one organic peroxide, in particular a hydroperoxide such as diisopropylbenzene hydroperoxide; and (c) at least one photoredox catalyst, preferably selected from complex compounds with ruthenium or iridium as the central atom, in particular with

[0165] ruthenium as the central atom and bipyridine or a simply or multiply substituted bipyridine derivative as ligands, or with iridium as the central atom and phenylpyridine or a simply or multiply substituted phenylpyridine derivative as ligands; and (d) at least one carbon black with a BET surface area of ​​20 to 400 m² 2 / g, determined according to ASTM D6556, and an OAN of 40 to 160 ml / 100g as corresponding substances contained in the adhesive film according to the invention.

[0166] According to preferred embodiments of the invention, this adhesive film also contains (f) up to 30 wt.% further additives and / or auxiliary materials, wherein the additives and / or auxiliary materials preferably include pyrogenic silica and / or titanium dioxide and / or poly(N-vinylcaprolactam).

[0167] According to further preferred embodiments of the invention, the adhesive film according to the invention contains

[0168] (a) 10 to 80 wt.%, preferably 20 to 70 wt.%, particularly preferably 30 to 60 wt.%, of at least one radically polymerizable compound, and

[0169] (b) 0.1 to 10.0 wt.%, preferably 0.5 to 9 wt.%, particularly preferably 0.5 to 8 wt.%, again preferably 0.5 to 5 wt.%, of at least one radical initiator, and

[0170] (c) 0.01 to 1.0 wt.%, preferably 0.01 to 0.75 wt.%, particularly preferably 0.01 to 0.5 wt.%, again preferably at least 0.05 wt.%, of at least one photoredox catalyst, and

[0171] (d) 0.01 to 10 wt.%, preferably 0.02 to 5 wt.%, particularly preferably 0.05 to 5 wt.% of at least one carbon black, and

[0172] (e) 10 to 85 wt.%, preferably 20 to 80 wt.%, particularly preferably 30 to 60 wt.%, of at least one non-reactive, film-forming polymer.

[0173] Preferably, the catalysts are (a) at least one radically polymerizable monomer, preferably 2-hydroxy-3-phenoxypropyl acrylate, and / or at least one radically polymerizable polymer, preferably at least one acrylate- and / or methacrylate-functionalized polyurethane; and (b) at least one organic peroxide, in particular a hydroperoxide such as diisopropylbenzene hydroperoxide; and (c) at least one photoredox catalyst, preferably selected from complex compounds with ruthenium or iridium as the central atom, in particular with ruthenium as the central atom and bipyridine or a singly or polysubstituted bipyridine derivative as a ligand, or with iridium as the central atom and phenylpyridine or a singly or polysubstituted phenylpyridine derivative as a ligand; and (d) at least one carbon black with a BET surface area of ​​20 to 400 m². 2 / g, determined according to ASTM D6556, and an OAN of 40 to 160 ml / 100g; and

[0174] (e) at least one non-reactive thermoplastic polyurethane as corresponding substances in the adhesive film according to the invention.

[0175] According to preferred embodiments of the invention, this adhesive film also contains

[0176] (f) up to 30 wt% further additives and / or excipients, wherein the additives and / or excipients preferably include pyrogenic silica and / or titanium dioxide and / or poly(N-vinylcaprolactam).

[0177] According to preferred embodiments, the adhesive film according to the invention contains - with or without (f) additional additives and / or auxiliary substances - (a) at least one radically polymerizable monomer, preferably 2-hydroxy-3-phenoxy-propyl acrylate, and no radically polymerizable polymer in combination with (e) at least one non-reactive film-forming polymer, in particular at least one non-reactive thermoplastic polyurethane.

[0178] According to further preferred embodiments of the invention, the adhesive film contains (a) 20 to 50 wt.% of at least one radically polymerizable compound, and (b) 0.5 to 9.0 wt.% of at least one radical initiator, and

[0179] (c) 0.01 to 0.75 wt% of at least one photoredox catalyst, preferably selected from complex compounds with ruthenium or iridium as the central atom, and

[0180] (d) 0.02 to 5 wt.% of at least one carbon black and

[0181] (e) 35 to 60 wt.% of at least one non-reactive, film-forming polymer and, if applicable, (f) 0 to 25 wt.% of other additives and / or excipients.

[0182] The selection of substances (a) to (f) shall be the same as the substances and combinations of substances mentioned in the embodiments described above.

[0183] According to particularly preferred embodiments, the light-curing, reactive, pressure-sensitive adhesive film according to the invention contains a mixture of the following components:

[0184] (a) 2-Hydroxy-3-phenoxy-propyl acrylate, and

[0185] (b) Diisopropylbenzene hydroperoxide, and

[0186] (c) Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate, and

[0187] (d) soot, especially furnace soot and

[0188] (e) thermoplastic polyurethane, in particular Irostic® S-6558-06, and

[0189] (f) rheological additive, in particular pyrogenic silica, and (f) poly(N-vinylcaprolactam).

[0190] Titanium dioxide, especially with anatase structure, can offer further advantages depending on the substrate to be bonded and other requirements.

[0191] According to particularly preferred embodiments, the adhesive film according to the invention contains

[0192] (a) 30 to 50 wt% 2-hydroxy-3-phenoxypropyl acrylate, and

[0193] (b) 1.0 to 3.0 wt% diisopropylbenzene hydroperoxide, and

[0194] (c) 0.05 to 0.2 wt% Tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate, and

[0195] (d) 0.05 to 3.0 wt.% carbon black, and

[0196] (e) 35 to 45 wt.% of the film-forming polymer, and

[0197] (f) 2 to 5 wt.% rheological additive, and

[0198] (f) 10 to 20 wt% poly(N-vinylcaprolactam) and, if applicable,

[0199] (f) 0.5 to 3.0 wt.% titanium dioxide based on the total weight of the components of the reactive adhesive film according to the invention.

[0200] According to further preferred embodiments of the invention, the adhesive film contains

[0201] (a) 80 to 99 wt.% of at least one radically polymerizable compound, and

[0202] (b) 0.5 to 9.0 wt.% of at least one radical initiator, and

[0203] (c) 0.01 to 0.75 wt% of at least one photoredox catalyst, preferably selected from complex compounds with ruthenium or iridium as the central atom, and

[0204] (d) 0.02 to 5 wt.% of at least one carbon black and

[0205] (e) 0 wt% of non-reactive film-forming polymers as well as

[0206] (f) 0 wt% other additives and / or excipients.

[0207] According to further preferred embodiments of the invention, the adhesive film contains

[0208] (a) 65 to 99 wt.% of at least one radically polymerizable compound, and

[0209] (b) 0.5 to 5.0 wt% of at least one radical initiator, and

[0210] (c) 0.01 to 0.75 wt% of at least one photoredox catalyst, preferably selected from complex compounds with ruthenium or iridium as the central atom, and

[0211] (d) 0.02 to 5 wt.% of at least one carbon black and

[0212] (e) 0 wt% of non-reactive film-forming polymers as well as

[0213] (f) up to 25% by weight of other additives and / or excipients.

[0214] In the two embodiments mentioned, the following are preferred: (a) at least one radically polymerizable polymer, preferably at least one acrylate- and / or methacrylate-functionalized polyurethane, which is preferably also film-forming; and (b) at least one organic peroxide, in particular a hydroperoxide such as diisopropylbenzene hydroperoxide; and (c) at least one photoredox catalyst, preferably selected from complex compounds with ruthenium or iridium as the central atom, in particular with ruthenium as the central atom and bipyridine or a singly or polysubstituted bipyridine derivative as a ligand, or with iridium as the central atom and phenylpyridine or a singly or polysubstituted phenylpyridine derivative as a ligand; and (d) at least one carbon black with a BET surface area of ​​20 to 400 m². 2 / g, determined according to ASTM D6556, and an OAN of 40 to 160 ml / 100g as corresponding substances contained in the adhesive film according to the invention.

[0215] In all the aforementioned embodiments, the sum of the quantities of the components equals 100% by weight.

[0216] The reactive adhesive film according to the invention preferably has a layer thickness (measured with a commercially available thickness gauge, e.g., DM 2000 from Wolf Messtechnik GmbH) in the range of 20 to 200 pm, more preferably 30 to 150 pm, more preferably 40 to 120 pm, and particularly preferably 50 to 100 pm. To produce greater layer thicknesses, it can be advantageous to laminate several adhesive film layers together.

[0217] Furthermore, the reactive adhesive film according to the invention is characterized in that it has adhesive properties before light curing, wherein "adhesive" is defined as above for polyurethane.

[0218] Furthermore, the light-curing, reactive, pressure-sensitive adhesive film according to the invention can comprise further films, foils, layers, carriers, adhesive films, pressure-sensitive adhesive films, release papers and / or release liners.

[0219] 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).

[0220] According to preferred embodiments of the invention, the adhesive film according to the invention is used as a single-layer film, also known to those skilled in the art as transfer adhesive tape.

[0221] Here too, the adhesive tape advantageously includes release papers and / or release liners for simplified storage.

[0222] According to further preferred embodiments of the invention, the reactive adhesive film (A1) according to the invention, together with a further reactive adhesive film (A2) according to the invention and a film, foil, layer or carrier (B), forms a multilayer reactive, pressure-sensitive adhesive tape.

[0223] The reactive, pressure-sensitive adhesive tape of these embodiments thus comprises the following layers: a light-curing, reactive, pressure-sensitive adhesive film (A1) according to the present invention; and a further light-curing, reactive, pressure-sensitive adhesive film (A2) according to the present invention; and a film, foil, layer, or carrier (B) arranged planarly between the two reactive, pressure-sensitive adhesive films (A1) and (A2).

[0224] This results in a three-layer, reactive, adhesive tape in the layer arrangement (A1 / B / A2).

[0225] According to preferred embodiments of the invention, the adhesive tape consists of the layers A1 / B / A2.

[0226] The adhesive tape can also comprise further layers, such as light-curing, reactive, pressure-sensitive adhesive films of the present inventions or other adhesive layers or further carrier layers.

[0227] Preferably the film, foil, layer or carrier (B) is a polyethylene, polypropylene or polyester film, most preferably a polyester film etched with trichloroacetic acid.

[0228] Preferably, the film, foil, layer, or carrier (B) arranged between the two reactive, pressure-sensitive adhesive films (A1) and (A2) according to the invention is a polyethylene, polypropylene, or polyester film, most preferably a polyester film etched with trichloroacetic acid. Such an etched polyester film with a thickness of 12 µm is available, for example, under the trade name Kemafoil® HPH 100 12p (Coveme SPA, San Lazzaro di Savena, Italy).

[0229] The adhesive tape also advantageously includes release papers and / or release liners for simplified storage.

[0230] Method for producing a reactive adhesive film

[0231] The inventive process for producing the reactive adhesive film comprises the following steps: i. Dissolving and / or finely dispersing the ingredients (a), (b), (c), (d) and, if present, (e) and / or (f) in one or more solvents or water under exclusion of UV light or visible light of the wavelength by which the respective photoredox catalyst is excited; ii. Mixing the dissolved or finely dispersed ingredients; iii. Coating a film, foil, layer, carrier, adhesive film, or pressure-sensitive adhesive film, preferably a release paper or liner, with the mixture of dissolved or finely dispersed ingredients according to step ii; iv. Evaporating the solvent or water; and v. Optionally, winding the reactive adhesive film into a roll.

[0232] According to step i., the ingredients (components) are dissolved or finely dispersed in one or more solvent(s) and / or water.

[0233] The ingredients are weighed, for example, into a brown screw-top jar, mixed with one or more solvents and / or water, and dissolved or finely dispersed by mixing with a commercially available stirrer or, alternatively, by rolling on a commercially available roller bench. Suitable solvents are known in the prior art, with solvents in which at least one of the ingredients exhibits good solubility being preferred. Acetone and methyl ethyl ketone (MEK) are particularly preferred.

[0234] For ingredients (a), (b), (c), (d), (e) and (f) all the above statements apply, including, where applicable, their manufacture, in particular in the case of (meth)acrylate-functionalized polyurethane as component (a).

[0235] The production of the light-curing, reactive, adhesive film according to the invention takes place at the latest from the addition of the photoredox catalyst under exclusion of UV light or visible light of the wavelength by which the respective photoredox catalyst is excited, in particular violet and blue light.

[0236] These are typically wavelengths below 500 nm, especially 300 to 500 nm. This exclusion can usually be achieved with commercially available yellow light lamps, as well as by covering normal light sources that contain UV and / or violet and blue light components in their wavelength spectrum with commercially available UV-protective yellow light films.

[0237] The dissolved or finely dispersed ingredients are mixed according to step ii. using conventional stirring equipment, in particular a dissolver. If necessary, the ingredients are dissolved, finely dispersed and mixed simultaneously.

[0238] In addition to mixing, the dissolver also breaks up agglomerates of primary carbon black particles. Optionally, another conventional mixing and stirring device can be connected before, in parallel, or after the dissolver. If necessary, the ingredients are simultaneously dissolved, finely dispersed, and mixed.

[0239] Subsequently, in a third step iii, a film, foil, layer, carrier, adhesive film, pressure-sensitive adhesive film, preferably a release liner or release paper, is coated with the mixture of the dissolved, finely dispersed ingredients. The coating is carried out according to the usual techniques known in the prior art.

[0240] After coating, the solvent or water is removed in a fourth step iv. by evaporation.

[0241] Depending on the solvents used, this is preferably done in the temperature range of 60 to 80°C.

[0242] If necessary, the reactive adhesive film can be wound into a roll in a further step.

[0243] For storage, the reactive adhesive film according to the invention is covered with a separating liner or paper.

[0244] The production of a three-layer, reactive, pressure-sensitive adhesive tape according to the invention is carried out by producing a first (A1) and a second (A2) reactive, pressure-sensitive adhesive film according to the invention, wherein the two reactive, pressure-sensitive adhesive films according to the invention are brought into contact with a film, a foil, a layer, or a carrier (B) optionally in a laminating process or by direct coating, so that a three-layer, reactive, pressure-sensitive adhesive tape in the layer arrangement (A1 / B / A2) results.

[0245] Substrates

[0246] Substrates suitable for bonding with the reactive adhesive film according to the invention include various plastics, metals, glass, and / or ceramics. The substrates to be bonded can be the same or different. They can be transparent or opaque.

[0247] The reactive adhesive film according to the invention is preferably used for bonding plastics, metals, and glass. Polycarbonate, polyamide, anodized aluminum, steel (e.g., stainless steel), and glass (especially surface-treated glass) are particularly preferred for bonding.

[0248] 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.

[0249] Suitable plastic substrates include, for example, polycarbonate (PC), polyamide (PA), acrylonitrile butadiene styrene copolymers (ABS), ABS / PC blends, PMMA, 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).

[0250] The substrates can be painted, printed, vapor-coated or sputtered.

[0251] Regarding their shape, the substrates to be bonded are preferably flat or two-dimensionally curved. Depending on the degree of curvature, however, three-dimensionally curved substrates can also be bonded with the reactive adhesive film 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.

[0252] 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.

[0253] Advantageously, the reactive adhesive film according to the invention can be used to bond components in the electronics sector, in particular smartphone and tablet components, such as touchscreens. Preferred bonding applications include the mounting of camera lenses, bonding of flexible displays of wearables (such as fitness trackers and smartwatches), mounting of antennas or backlight units in smartphones or tablets, FPC (flexible printed circuit) mounting or membrane lamination, and mounting of loudspeaker drivers.

[0254] Bonding process

[0255] The reactive adhesive film according to the invention can be used in a method for bonding two substrates, e.g. substrate 1 (e.g. polycarbonate) with another substrate 2 (e.g. metal), to obtain a composite body.

[0256] This inventive method for bonding two substrates preferably comprises the following steps:

[0257] (xi) Providing a first substrate S1 ;

[0258] (xii) Providing a second substrate S2;

[0259] (xiii) Arranging the reactive adhesive film or the reactive adhesive tape according to the invention on substrate S1;

[0260] (xiv) Either before or after the adhesive film or tape has been applied to the substrate S1: Irradiating the adhesive film or tape with UV or blue light to form an irradiated adhesive film or tape and to cause hardening;

[0261] (xv) Arrange the two substrates S1 and S2 so that they are joined together by the irradiated adhesive film or the irradiated tape; and

[0262] (xvi) After assembly: Allow the irradiated adhesive film or tape to cure as a result of the irradiation. Alternatively, the irradiation in step (xiv) can also take place after the assembly or joining of the two substrates (xv), particularly if at least one substrate is transparent to the activating radiation.

[0263] Composite body

[0264] Furthermore, according to the invention, a composite body comprising at least two bonding surfaces is provided, in which the two bonding surfaces are connected by the hardened reactive adhesive film according to the invention or by the hardened reactive adhesive tape as defined above.

[0265] Product features

[0266] The reactive adhesive film according to the invention exhibits outstanding product properties that were not foreseeable even for those skilled in the art. Depending on the photoredox catalyst used, the adhesive film can be cured with a commercially available UV LED lamp or a blue LED lamp (e.g., wavelengths of 365 nm, 385 nm, 395 nm, 405 nm, 450 nm, and 460 nm). Surprisingly, it was found that in many cases, either a UV LED lamp or a blue LED lamp is equally suitable. A commercially available mercury vapor UV lamp may also be suitable.

[0267] Examples of suitable LED light sources for curing the reactive adhesive films according to the invention include the following products from Hönle (Dr. Hönle AG, Gilching, Germany, https: / / www.hoenle.de / ): a) LED Spot 100 HP IC 365 nm (UV LED) b) LED Spot 100 HP IC 460 nm (blue light LED)

[0268] The LED-Cube 100 IC, also from Hönle, is an irradiation chamber specifically designed for these light sources. The appropriate dose is approximately in the range of 10 to 120 J / cm². 2 For this purpose, a power output of 30% to 90% is typically selected on the aforementioned devices. The irradiation time is chosen to be between 10 and 120 seconds. The distance between the light source and the reactive adhesive film according to the invention is approximately 2 to 10 cm. When using other devices with different power outputs, significant deviations from the aforementioned guideline values ​​are to be expected.

[0269] After irradiation, the adhesive film does not harden instantly. It initially remains tacky. Bonding or joining of the substrates is possible within a period of at least three minutes, and depending on the photoredox catalyst used and the exact adhesive formulation, sometimes up to 10 minutes. In other words, the 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 film according to the invention cures completely within a period of approximately 24 hours after the end of irradiation, and at the latest within 48 hours. Curing occurs independently of light and therefore also in the dark. Thus, even non-transparent substrates can be bonded with the adhesive film according to the invention.

[0270] The reactive adhesive film according to the invention achieves high bond strengths. In push-out tests, values ​​greater than 8 MPa can be achieved when bonding polycarbonate test specimens (see examples). Bonds of steel and anodized aluminum also result in similarly high bond strengths. This order of magnitude is generally referred to as "structural".

[0271] Surprisingly, it was found that the light-curing, reactive, pressure-sensitive adhesive film according to the invention exhibits improved storage stability after exposure to ambient light compared to the prior art. The effect of light exposure was tested by exposing die-cut pieces of the light-curing, reactive adhesive film and the three-layer, reactive adhesive tape according to the invention to daylight for 14 hours at 23°C and 50% relative humidity in an interior space with a wide window front (facing northwest) and subsequently storing them in the dark. The light exposure resulted from a combination of ceiling lighting and daylight filtering through the windows, with the die-cut pieces positioned to avoid direct sunlight.The measurement of the total light dose acting on the die-cutting pieces during the 14 hours yielded the following result: UV-A light of the wavelength range 340 to 405 nm: 1000 mJ / cm. 2 , visible light in the wavelength range 360 ​​to 550 nm: 4700 mJ / cm² 2 .

[0272] The dose of UV light and visible light was measured using a UV meter from the company Hönle (Dr. Hönle AG, Gilching, Germany, https: / / www.hoenle.de / ), the UV light with the area sensor UVA F0 (340-405 nm), the visible light with the area sensor VIS F1 (360-550 nm).

[0273] After exposure to light, the die-cut pieces were stored in a drying oven at 40°C for one week in a first series of tests, and in a second series of tests for 10 weeks at 23°C and 50% relative humidity. These storage periods took place in the dark.

[0274] Following these storage procedures, the irradiation and bonding for the push-out tests were carried out.

[0275] Results of the push-out tests: After 14 hours of exposure to ambient light and subsequent extended storage, the light-curing, reactive adhesive films and the light-curing, three-layer, reactive adhesive tapes according to the invention do not reach the push-out freshness values. However, after such light exposure and subsequent storage, the light-curing, reactive, pressure-sensitive adhesive films according to claim 1 and the light-curing, three-layer, reactive adhesive tapes according to the invention show significantly improved results compared to the reference examples. With particularly advantageous embodiments of the adhesive film and tape according to the invention, so-called structural bond strengths are achieved, which, according to the views expressed in this document, begin at approximately 5 MPa. In the examples, peak values ​​of up to 8 MPa were achieved after light exposure and storage.

[0276] On average, in the examples, after 14 hours of exposure to ambient light and subsequent one week of storage at 40°C, push-out values ​​of 84% of the fresh values ​​were achieved. In the comparison examples, push-out values ​​of only 16% of the fresh value were achieved on average.

[0277] After 14 hours of exposure to ambient light and subsequent 10-week storage at 23°C, average push-out values ​​of 77% of the fresh values ​​were achieved, while the comparison examples here only reached an average of 7% of the fresh value values.

[0278] The storage stability after exposure to light could thus be clearly improved with the adhesive film and tape according to the invention.

[0279] These results are achieved both with formulations in which the carbon black content is relatively low at 0.25 wt.%, so that these formulations appear not black but only greyish, and with formulations in which the carbon black content is 2 wt.%, resulting in the corresponding adhesive films being jet black.

[0280] Surprisingly, compared to examples 5 to 10, the formulations in examples 1 to 18 always harden so slowly that there is sufficient time to carry out the bonding. The open time is at least 3 minutes.

[0281] Surprisingly, the curing process is not inhibited by a carbon black content of 2 wt%, which results in deep black adhesive films. Consequently, consistently high push-out values ​​are achieved compared to examples 5 to 10.

[0282] Experimental Part The following examples serve to illustrate the present invention, but should in no way be understood as limiting the scope of protection. Table 1 lists the raw materials and materials used to produce the light-curing, pressure-sensitive, reactive adhesive film, the three-layer, light-curing, reactive, pressure-sensitive adhesive tape, and the comparative examples according to the invention, each with its trade name, manufacturer or supplier information, and the technical data relevant to this invention.

[0283] Table 1

[0284] * The hydroxyl number of the polyester diol was determined according to DIN 53240. According to this method, the hydroxyl number (OHZ) is given in the unit [mg KOH / g]. It corresponds to the amount of KOH in [mg] bound during the acetylation of 1 g of polyol.

[0285] Acetic acid is equivalent. For the purpose of simplifying formulation calculations, the hydroxyl value is converted to the unit [mmol OH / kg] in this document.

[0286] This is done according to the following formula: OHZ [mmol OH / kg] = OHZ[mg KOH / g] x1000 / 56.1.

[0287] 56, 1 corresponds to the numerical value of the molar mass of KOH.

[0288] The OH numbers and NCO numbers of the methacrylate-functionalized diol and the diisocyanate were calculated directly from the respective molar masses, taking into account the respective functionality.

[0289] Furthermore, commercially available siliconized release liners (release films) were used. Acetone (CAS No.: 67-64-1), methyl ethyl ketone (CAS No.: 78-93-3), isopropanol (CAS No.: 67-63-0), and fully demineralized water were used as solvents in the examples and comparative examples.

[0290] Preparation of a solution of acrylate- or methacrylate-functionalized polyurethane:

[0291] The methacrylate-functionalized polyurethane was prepared by first weighing out the polyester diol and stirring it under vacuum at 70 °C for two hours in a standard heated and evacuable laboratory mixer (e.g., from PC Laborsystem). The diol was then transferred to a screw-top jar, and after brief cooling, the solvent (acetone), 2,3-dihydroxypropyl methacrylate, and catalyst (Coscat® 83) were added. The mixture was stirred for 30 minutes without vacuum or heating using a standard laboratory stirrer. The diisocyanate was then added and stirred in homogeneously. The chemically reacting mixture was stirred for another 90 minutes, with the small amount of solvent that escaped being continuously replenished. To complete the reaction, the sealed screw-top jar was stored in a warming oven at 40 °C for 7 days.

[0292] The following polyurethane solution was produced:

[0293] PU-1 : NCO / OH ratio: 0.93 Preparation of a solution of the film-forming polymer (film-forming solution)

[0294] A solution of the film-forming polymer was prepared as follows:

[0295] IROSTIC® S-6558-06 solution:

[0296] A 20% solution of the film-forming polymer was prepared by first weighing 120 g of Irostic® S-6558-06 into a screw-top jar along with 240 g of acetone and 240 g of methyl ethyl ketone, and then sealing the jar. The Irostic® S-6558-06 was completely dissolved by rolling the jar on a standard rolling bench for several days. Depending on the rolling speed, this process took approximately one to seven days. Alternatively, the solution can also be prepared by stirring the Irostic® S-6558-06 granules in the acetone and methyl ethyl ketone mixture using a standard laboratory stirrer.

[0297] Preparation of a poly(N-vinylcaprolactam) solution:

[0298] A conventional 10 L glass reactor for radical polymerizations was filled with 4.0 kg of N-vinylcaprolactam, 3.84 kg of acetone, and 0.16 kg of isopropanol. Under nitrogen gas purge, the reactor was heated to a jacket temperature of 65 °C while stirring at 70 rpm. Upon reaching an internal temperature of 58 °C, 2.0 g of Vazo® 67 were added. After one hour of further stirring at 65 °C, another 2.0 g of Vazo® 67 was added. After six hours of further stirring at 65 °C, the stirrer speed was reduced to 35 rpm. The reaction time was 20 hours. After this time, the solution was cooled to room temperature and diluted with acetone to a solids content of 40.0 wt%. The molar mass of the resulting poly(N-vinylcaprolactam) was determined by thermal field-flow fractionation. Result: Mn = 74000 g / mol, Mw = 116500 g / mol.

[0299] Preparation of an aqueous photoredox catalyst solution

[0300] A 5 wt% aqueous solution of the photoredox catalyst Tris(2,2'- bipyridyl)ruthenium(II) chloride hexahydrate was prepared.

[0301] Aqueous Tris(2,2'-bipyridyl)ruthenium(II) Chloride Hexahydrate Solution

[0302] Under yellow light, 5 g of tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate and 95 g of fully demineralized water were weighed into a brown screw-top jar. The jar was sealed. The tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate was completely dissolved by rolling the jar on a rolling bench for 8 hours.

[0303] Production of a reactive adhesive film and a three-layer reactive adhesive tape according to the invention.

[0304] Explanation using example 3:

[0305] In a brown screw-top jar, 69.10 g of the 20 wt% film-forming solution of I ROSTIC® S-6558-06 in acetone / methyl ethyl ketone (50 / 50), 13.18 g of the 40 wt% poly(N-vinylcaprolactam) solution, 13.70 g of 2-hydroxy-3-phenoxypropyl acrylate, 0.09 g of Printex® 80, and 1.34 g of Aerosil® R202 were weighed out and mixed with a standard laboratory stirrer for 15 minutes at medium speed (500–1000 rpm). Then, 1.76 g of DIHP® INEOS (containing 50 wt% diisopropylbenzene hydroperoxide) was added and mixed in for 5 minutes at medium speed.

[0306] The mixture was then dispersed for 30 minutes using the RE 166 dissolver from IKA-Werke GmbH at a medium speed of 2000-3000 revolutions per minute.

[0307] All further operations were performed under yellow light. The fluorescent lamp LT35WT5EQ / Yellow Special from NARVA Beleuchtungs GmbH (NARVA Beleuchtungs GmbH + Co. KG, Brand-Erbisdorf, Germany, www.narva-bel.de), which blocks wavelengths below 500 nm, was chosen as the yellow light ceiling illumination. To mask any remaining residual light from other light sources, the yellow filter Metolight SFLY-5 (ASMETEC GmbH, Kirchheimbolanden, Germany, www.asmetec.de), which filters out wavelengths below 470 nm, was selected.

[0308] 0.84 g of the 5 wt% aqueous tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate solution were added and mixed for 5 minutes using a laboratory stirrer at medium speed. The mixture was then further mixed for 24 hours on a standard rolling bench.

[0309] The resulting homogeneous mixture was spread three times successively onto a standard, transparent, UV-transmitting, siliconized polyester film (release liner) using a standard laboratory spreading table (for example, from SMO, Sondermaschinen Oschersleben GmbH, Oschersleben, Germany) and a spreading knife, resulting in three films. The solvent was then evaporated for 15 minutes at 60 °C in a circulating air drying oven. The spreading gap was varied. Twice it was adjusted to yield a 50 µm thick film after solvent evaporation. In the third spreading test, the gap was adjusted to yield a 100 µm thick film after solvent evaporation.The resulting light-curing, reactive, pressure-sensitive adhesive film, 100 µm thick, was covered with a second commercially available, transparent, UV-transmitting, siliconized polyester film (release liner). Circular blanks (discs) with a diameter of 21 mm were then die-cut from this film.

[0310] To produce a three-layer reactive adhesive tape according to the invention, the first of the two 50 µm thick reactive adhesive films was laminated onto the trichloroacetic acid-etched polyester film Kemafoil® HPH 100 12p. This was done at room temperature using a smooth laminating roller (pressure roller) with light pressure. The second 50 µm thick reactive adhesive film was then laminated in the same way onto the other side of the trichloroacetic acid-etched polyester film. The resulting three-layer, light-curing, reactive pressure-sensitive adhesive tape was covered on both sides with a commercially available, transparent, UV-transmitting, siliconized polyester film (release liner). Subsequently, ring-shaped dies (rings) with an outer diameter of 18 mm and an inner diameter of 13 mm were die-cut from this.

[0311] The percentage composition of the input weights for the preparation of the solution / mixture of the light-curing, reactive, pressure-sensitive adhesive film, as well as the percentage composition of the light-curing, reactive, pressure-sensitive adhesive film itself (without solvent), can be found in the two tables, Example 3.

[0312] The reactive adhesive films and the three-layer reactive adhesive tapes according to the invention of the further examples and comparative examples were produced in an analogous manner to that in Example 3.

[0313] The following tables provide information on the percentage compositions of the solutions / mixtures used to produce the reactive adhesive films and the percentage compositions of the solvent-free reactive adhesive films in the further examples and comparative examples. Example 1, Percentage composition of the solution / mixture used to produce the reactive adhesive film

[0314] Example 1, Percentage composition of the reactive adhesive film

[0315] Example 2, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0316] Example 2, Percentage composition of the reactive adhesive film

[0317] Example 3, Percentage composition of the solution / mixture for the production of the reactive adhesive film Example 3, Percentage composition of the reactive adhesive film

[0318] Example 4, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0319] Example 4, Percentage composition of the reactive adhesive film Example 5, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0320] Example 5, Percentage composition of the reactive adhesive film

[0321] Example 6, Percentage composition of the solution / mixture for the production of the reactive adhesive film Example 6, Percentage composition of the reactive adhesive film Example 7, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0322] Example 7, Percentage composition of the reactive adhesive film Example 8, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0323] Example 8, Percentage composition of the reactive adhesive film

[0324] Example 9, Percentage composition of the solution / mixture for the production of the reactive adhesive film Example 9, Percentage composition of the reactive adhesive film

[0325] Example 10, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0326] Example 10, Percentage composition of the reactive adhesive film Example 11, Percentage composition of the solution / mixture for the production of the reactive adhesive film Example 11, Percentage composition of the reactive adhesive film

[0327] Example 12, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0328] Example 12, Percentage composition of the reactive adhesive film

[0329] Example 13, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0330] Example 13, Percentage composition of the reactive adhesive film

[0331]

[0332] Example 14, Percentage composition of the solution / mixture for the production of the reactive adhesive film Example 14, Percentage composition of the reactive adhesive film Example 15, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0333] Example 15, Percentage composition of the reactive adhesive film

[0334] Example 16, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0335] Example 16, Percentage composition of the reactive adhesive film

[0336] Example 17, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0337] Example 17, Percentage composition of the reactive adhesive film Example 18, Percentage composition of the solution / mixture for the production of the reactive adhesive film

[0338] Example 18, Percentage composition of the reactive adhesive film

[0339] Comparative examples

[0340] Comparative example 1, Percentage composition of the solution / mixture Comparative example 1, Percentage composition of the film

[0341] Comparative example 2, Percentage composition of the solution / mixture

[0342] Comparative example 2, Percentage composition of the film

[0343] Comparative example 3, Percentage composition of the solution / mixture

[0344] Comparative example 3, Percentage composition of the film

[0345] Comparative example 4, Percentage composition of the solution / mixture

[0346] Comparative example 4, Percentage composition of the film Comparative example 5, Percentage composition of the solution / mixture

[0347] Comparative example 5, Percentage composition of the film

[0348] Comparative example 6, Percentage composition of the solution / mixture Comparative example 6, Percentage composition of the film

[0349] Comparative example 7, Percentage composition of the solution / mixture

[0350] Comparative example 7, Percentage composition of the film Comparative example 8, Percentage composition of the solution / mixture

[0351] Comparative example 8, Percentage composition of the film

[0352] Comparative example 9, Percentage composition of the solution / mixture Comparative example 9, Percentage composition of the film

[0353] Comparative example 10, Percentage composition of the solution / mixture

[0354] Comparative example 10, Percentage composition of the film Light exposure and storage

[0355] The resulting die-cut parts were stored in four independent test series, some having been exposed to light beforehand. This was followed by irradiation, bonding for push-out tests, and measurement of the push-out values.

[0356] First series of storage tests:

[0357] The die-cut pieces were stored for three days at 23 °C and 50% relative humidity in a lightproof plastic container. During this time, they were protected from light. The push-out values ​​obtained with these die-cut pieces are the so-called fresh values.

[0358] Second storage test series:

[0359] The die-cut blanks were stored for six months at 23 °C and 50% relative humidity in a lightproof plastic container. During this time, they were completely protected from light. The push-out values ​​obtained from these blanks serve to verify whether a storage stability problem exists, independent of light exposure.

[0360] Third storage test series:

[0361] The die-cut pieces were exposed to daylight for 14 hours at 23°C and 50% relative humidity in an interior space with a wide window front (facing northwest). The pieces were positioned to avoid direct sunlight. The permanently switched-on ceiling lights also contributed to the light exposure. The total light dose applied to the die-cut pieces during the 14 hours was: UV-A light in the wavelength range of 340 to 405 nm: 800 to 1200 mJ / cm²2 , visible light in the wavelength range 360 ​​to 550 nm: 4000 to 5400 mJ / cm² 2 .

[0362] The dose of UV light and visible light was measured using a UV meter from the company Hönle (Dr. Hönle AG, Gilching, Germany, https: / / www.hoenle.de / ), the UV light with the area sensor UVA F0 (340-405 nm), the visible light with the area sensor VIS F1 (360-550 nm).

[0363] After this exposure to light, the die-cut pieces were stored in a dark, heated cabinet at 40°C for one week.

[0364] Fourth storage test series:

[0365] As in the third series of experiments, the die-cut pieces were exposed to daylight in an indoor space for hours at 23°C and 50% relative humidity.

[0366] After this exposure to light, the die-cut pieces were stored in the dark for 10 weeks at 23 °C and 50% relative humidity.

[0367] In summary, the following combinations of light exposure and storage conditions were carried out:

[0368] Table 2: Summary of the combinations of light exposure and storage carried out

[0369] Push-out test

[0370] 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.

[0371] Test specimens for the push-out test

[0372] Circular plates (rounds) with a diameter of 21 mm were used.

[0373] Square perforated plates with sides measuring 40 mm were also used. The hole is centrally located in the middle of each plate. It is round, with a diameter of 9 mm. The discs used were made of polycarbonate, anodized aluminum, and SUS steel. The square perforated plates used were made of polycarbonate, polyamide, anodized aluminum, and SUS steel.

[0374] The following test specimens were used: a) Discs: Plastic discs made of polycarbonate (PC) Makrolon 099, milled burr-free, 21x3mm; Discs made of anodized aluminum (Al), alloy 5005A, AIMgl, anodized E6 EV1, 21x2 mm

[0375] Steel discs, steel grade VA1.4301 (equivalent to SUS 304), outer contour laser-cut, one side mirror-polished, 21x2 mm b) Square perforated plates:

[0376] Plastic test specimen made of polycarbonate (PC), manufactured by Makroform 099, 40x40x4 mm, plastic hole in the center, D = 9 mm

[0377] Test specimen made of aluminum (Al), alloy 5005A, AIMgl, anodized E6 EV1, 40x40x2 mm, aluminum bore in the center, D = 9 mm

[0378] Steel test specimen, steel grade VA1.4301 (equivalent to SUS 304), inner and outer contours laser-cut, surfaces mirror-polished, 40x40x3 mm, steel bore in the center, D = 9 mm

[0379] The polycarbonate and aluminum test specimens were sourced from Rocholl GmbH (Eschelbronn, Germany, https: / / rocholl.eu / ). The steel test specimens were supplied by Classen GmbH (Rellingen, Germany, www.classen-laser.de / ).

[0380] Sample preparation for the push-out test

[0381] A distinction is made between the inventive, single-layer, light-curing, reactive, pressure-sensitive adhesive films, which were supplied as 100 pm thick circular die-cut blanks (discs), and the inventive, three-layer, reactive adhesive tapes, which consist of two 50 pm thick reactive films and the 12 pm thick polyester film etched with trichloroacetic acid, arranged in the middle between the two 50 pm thick reactive films, and which were supplied as die-cut rings.

[0382] The separating liners of the die-cut pieces were each peeled off from one side of the die-cut piece.

[0383] The stamped parts were each placed centrally on a test specimen disc.

[0384] The die-cut pieces now adhered to the test specimen rounds.

[0385] The separating liner remaining on the die-cut blanks was then removed. The test specimen discs were now equipped with the single-layer reactive adhesive films (discs) and the three-layer reactive adhesive tapes (rings).

[0386] Irradiation for the push-out test

[0387] The irradiations were performed in the first series of experiments exclusively with UV LED light (365 nm) and in the second series exclusively with a blue LED light (460 nm). The dose was selected as follows:

[0388] - Examples 1-6, 10-18, comparative examples 1-5, 7, 9:

[0389] LED Spot 100 HP IC 365 nm (UV LED): 32.0 - 33.0 J / cm 2

[0390] LED Spot 100 HP IC 460 nm (blue light LED): 53.0 - 54.0 J / cm

[0391] - Examples 7-9, comparative examples 6, 8, 10:

[0392] LED Spot 100 HP IC 365 nm (UV LED): 64.0 - 66.0 J / cm 2

[0393] LED Spot 100 HP IC 460 nm (blue light LED): 106.0 - 108.0 J / cm 2

[0394] The dose of UV and blue LED light was measured using a UV meter from the company Hönle (Dr. Hönle AG, Gilching, Germany, https: / / www.hoenle.de / ), the UV light with the area sensor UVA F0 (340-405 nm), the blue light LED with the area sensor VIS F1 (360-550 nm).

[0395] The time interval between the end of the irradiation and the joining of the test specimens was consistently between one and two minutes. Multiple checks confirmed that time intervals of at least three minutes or more are also possible without any deterioration in bond strength.

[0396] Adhesive for the push-out test

[0397] The test specimen discs, each equipped with an irradiated die, were positioned on the perforated plate with the exposed side of the die facing upwards, such that the center of the disc and the center of the hole in the perforated plate were aligned. The assembly, consisting of the square perforated plate, the irradiated die, and the test specimen disc, held together by the adhesive properties of the dies, was then pressed using a press from Howe Elektrotechnik eK (Glinde, Germany, https: / / howe-hamburg.de / ). The pressing parameters were: 3 bar, 30 seconds.

[0398] After pressing, the composite was stored for 48 hours at 23 °C and 50% relative humidity (RH). This resulted in a gradual curing reaction within the die-cut pieces and a gradually increasing adhesion between the die-cut pieces and the test specimens. This led to bonding with a gradual increase in strength over time. Push-out tests were then performed.

[0399] The test specimens were bonded in the following combinations:

[0400] • PC disc vs. PC plate • Aluminum disc vs. aluminum plate

[0401] • Steel disc against steel plate

[0402] The bonding surfaces were:

[0403] Circular die-cut blanks (discs): 283 mm 2 (taking into account the 9 mm hole in the plates)

[0404] Ring-shaped die-cuts: 122 mm 2

[0405] Conducting the push-out test

[0406] 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 test specimen blank (i.e., parallel to the normal vector to the test specimen plane; centered on the hole) until the adhesive bond failed sufficiently to register a 50% pressure drop. The pressure acting immediately before the pressure drop is the maximum pressure Pmax. This value corresponds to the push-out value [MPa] given in the table. All measurements were performed in an air-conditioned room at 23 °C and 50% relative humidity (RH).

[0407] Push-out results

[0408] In all examples (inventive and comparative examples), the mean value from three individual measurements was determined.

[0409] Fracture patterns:

[0410] A = Adhesive; K = Cohesive; M = Mixed fracture

[0411] Other abbreviations: d = days; h = hours; = = corresponds to

[0412] Example 1

[0413] Single-layer product (round)

[0414] Three-layer product (ring)

[0415] Example 2

[0416] Single-layer product (round)

[0417] Three-layer product (ring)

[0418]

[0419] Example 3

[0420] Single-layer product (round)

[0421]

[0422] Three-layer product (ring)

[0423]

[0424] Example 4

[0425] Single-layer product (round)

[0426]

[0427] Three-layer product (ring)

[0428] Example 5

[0429] Single-layer product (round)

[0430] Three-layer product (ring)

[0431]

[0432] Example 6 Single-layer product (round)

[0433] Three-layer product (ring)

[0434] Example 7 Single-layer product (round)

[0435] Three-layer product (ring) Example 8

[0436] Single-layer product (round) Three-layer product (ring) Example 9

[0437] Single-layer product (round) Three-layer product (ring) Example 10

[0438] Single-layer product (round) Three-layer product (ring) Example 11

[0439] Single-layer product (round) Three-layer product (ring) Example 12

[0440] Single-layer product (round) Three-layer product (ring) Example 13

[0441] Single-layer product (round) Three-layer product (ring) Example 14

[0442] Single-layer product (round) Three-layer product (ring) Example 15

[0443] Single-layer product (round) Three-layer product (ring) Example 16

[0444] Single-layer product (round) Three-layer product (ring) Example 17

[0445] Single-layer product (round) Three-layer product (ring) Example 18

[0446] Single-layer product (round) Three-layer product (ring) Comparative example 1

[0447] Single-layer product (round) Three-layer product (ring) Comparative example 2

[0448] Single-layer product (round) Three-layer product (ring) Comparative example 3

[0449] Single-layer product (round) Three-layer product (ring) Comparative example 4

[0450] Single-layer product (round) Three-layer product (ring) Comparative example 5

[0451] Single-layer product (round) Comparative example 6

[0452] Single-layer product (round) Comparative example 7

[0453] Single-layer product (round)

[0454] Comparative example 8: Single-layer product (round) Comparative example 9

[0455] Single-layer product (round)

[0456] Comparative example 10 Single-layer product (round) Statistical summary of the results

[0457] The following table lists the averaged push-out results for the 18 examples after each storage period, expressed as percentages of the fresh value. Fresh values ​​are defined as 100%. The minimum and maximum push-out results after each storage period are also listed, likewise as percentages of the fresh value.

[0458] Table 3: Examples 1 to 18:

[0459] The following table lists the averaged push-out results for comparison examples 1 to 4 after each storage period, expressed as percentages of the fresh value. Fresh values ​​are defined as 100%. The minimum and maximum push-out results after each storage period are also listed, again as percentages of the fresh value. Table 4: Comparison Examples 1 to 4:

[0460] Discussion of the results

[0461] From comparative examples 1 to 4 it becomes clear that with light-curing, reactive adhesive films based on formulations according to a broader claim 1, which does not include the restriction by (d) carbon black, good push-out values ​​and good storage stability can be achieved, but that the storage stability is considerably limited if these adhesive films are previously exposed to normal ambient light indoors for several hours.

[0462] Examples 5 to 10 clearly show that replacing (b) the radical initiator or (c) the photoredox catalyst, or both, with a commercially available photoinitiator results in comparatively very low push-out values, which are below the bond strengths achievable with non-reactive, pressure-sensitive adhesive films. This is attributed to the fact that either curing occurs immediately after irradiation within milliseconds, leaving no time to perform the bonding, or curing does not occur at all because the carbon black content is too high.

[0463] Examples 1 to 18, on the other hand, represent significant improvements.

[0464] Although these light-curing, reactive adhesive films do not reach the push-out freshness values ​​after 14 hours of light exposure and subsequent extended storage, the light-curing, reactive, pressure-sensitive adhesive films according to claim 1 of the invention achieve significantly improved storage stability after light exposure compared to the examples described above. In some cases, so-called structural bond strengths are achieved, which, according to the opinion expressed in this document, begin at approximately 5 MPa.

[0465] These results are achieved both with formulations in which the carbon black content is relatively low at 0.25 wt.%, so that these formulations appear not black but only greyish, and with formulations in which the carbon black content is 2 wt.%, resulting in the corresponding adhesive films being jet black.

[0466] Surprisingly, compared to examples 5 to 10, the formulations in examples 1 to 18 always cure so slowly that sufficient time remains for bonding. The open time is at least 3 minutes. Surprisingly, a carbon black content of 2 wt% does not inhibit curing. Consequently, consistently high push-out values ​​are achieved compared to examples 5 to 10.

Claims

Patent claims 1. Light-curing, reactive, tacky adhesive film, comprising (a) at least one radically polymerizable compound, and (b) at least one radical initiator, and (c) at least one photoredox catalyst, and (d) at least one soot.

2. Light-curing, reactive, tacky adhesive film according to claim 1, characterized in that the at least one radically polymerizable compound (a) is selected from the group consisting of radically polymerizable monomers, radically polymerizable oligomers and radically polymerizable polymers.

3. Light-curing, reactive, pressure-sensitive adhesive film according to claim 2, characterized in that the radically polymerizable monomer or oligomer is selected from the group consisting of acrylic acid esters, methacrylic acid esters, vinyl compounds, compounds with olefinic carbon-carbon double bonds, crosslinking radically polymerizable compounds such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, higher functional acrylates and higher functional methacrylates, wherein the radically polymerizable monomer is preferably selected from the group consisting of 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 2-[2-(methacryloyloxy)ethoxycarbonyl]benzoic acid, 2-[[(phenylamino)carbonyl]oxy]ethyl methacrylate, 2-Tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenylprop-2-enoate, (5-ethyl-1,3-dioxan-5-yl)methyl acrylate, (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate, di(ethylene glycol)-2-ethylhexyl ether acrylate, (2,2-dimethyl-1,3-dioxolan-4-yl)methylprop-2-enoate, 2-succinic acid mono-[2-(acryloyloxy) ethyl ester], 2-succinic acid mono-[2-(methacryloyloxy)ethyl ester], (2,2-pentamethylene-1,3-oxazolidyl-3)ethyl methacrylate, 2-hydroxy-3-(prop-2-enoyloxy)propyl-2-methyl-2-propylhexanoate, 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate, stearyl acrylate, stearyl methacrylate, and the crosslinking reactive monomers diurethane dimethacrylate (isomer mixture), bisphenol A diglycidyl methacrylate (BIS-GMA), Bisphenol A dimethacrylate (BIS-DMA), Ethylene glycol diacrylate, Ethylene glycol dimethacrylate, Trimethyloylpropane propoxylate triacrylate, Trimethyloylpropane triacrylate and, Di(trimethylolpropane)tetraacrylate, wherein 2-hydroxy-3-phenoxy-propylacrylate, 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate and / or diurethane dimethacrylate are particularly preferred.

4. Light-curing, reactive, tacky adhesive film according to one of the preceding claims, characterized in that (a) the radically polymerizable compound includes at least one acrylate and / or methacrylate functionalized polyurethane.

5. Light-curing, reactive, tacky adhesive film according to one of the preceding claims, characterized in that (a) 2-hydroxy-3-phenoxy-propyl acrylate is included as a radically polymerizable compound.

6. Light-curing, reactive, tacky adhesive film after one of the preceding steps Claims, characterized in that the at least one photoredox catalyst (c) comprises ruthenium as the central atom and bipyridine or a singly or multiply substituted bipyridine derivative as ligands, or iridium as the central atom and phenylpyridine or a singly or multiply substituted phenylpyridine derivative as ligands.

7. Light-curing, reactive, tacky adhesive film after one of the preceding Claims, characterized in that the at least one photoredox catalyst (c) [Tris(2,2'-bipyridyl)ruthenium(ll)] 2+ , Tris[2-(2,4-difluorophenyl)pyridine]iridium(II I) and / or Tris(2-phenylpyridinato)iridium(II I).

8. Light-curing, reactive, tacky adhesive film after one of the preceding Claims, characterized in that it contains at least one film-forming polymer (e), which is preferably a non-reactive thermoplastic polymer, a non-reactive elastomer and / or a non-reactive thermoplastic elastomer, in particular a non-reactive thermoplastic polyurethane.

9. Light-curing, reactive, tacky adhesive film comprising one of the preceding claims (a) 10 to 99 wt.%, preferably 20 to 99 wt.%, particularly preferably 30 to 99 wt.% of at least one radically polymerizable compound, and (b) 0.1 to 10.0 wt.%, preferably 0.5 to 9 wt.%, particularly preferably 0.5 to 8 wt.%, again preferably 0.5 to 5 wt.%, of at least one radical initiator, and (c) 0.01 to 1.0 wt.%, preferably 0.01 to 0.75 wt.%, particularly preferably 0.01 to 0.5 wt.%, again preferably at least 0.05 wt.%, of at least one photoredox catalyst, preferably selected from complex compounds with ruthenium or iridium as the central atom, and (d) 0.01 to 10 wt.%, preferably 0.02 to 5 wt.%, particularly preferably 0.05 to 5 wt.%, of at least one carbon black.

10. Light-curing, reactive, pressure-sensitive adhesive film after one of the preceding Claims, characterized in that it (f) comprises up to 30 wt.% further additives and / or auxiliary substances, wherein the additives and / or auxiliary substances preferably include pyrogenic silica and / or titanium dioxide and / or poly(N-vinylcaprolactam).

11. Light-curing, reactive, pressure-sensitive adhesive film according to any of the preceding claims, comprising further films, foils, layers, carriers, adhesive films, pressure-sensitive adhesive films, release papers and / or release liners.

12. Light-curing, reactive, pressure-sensitive adhesive tape comprising the layers: a light-curing, reactive, pressure-sensitive adhesive film (A1) according to any one of claims 1 to 10; and a further reactive, pressure-sensitive adhesive film (A2) according to any one of claims 1 to 10; and a film, foil, layer, or carrier (B) arranged planarly between the two reactive, pressure-sensitive adhesive films (A1) and (A2).

13. A method for producing a reactive, tacky adhesive film according to any one of claims 1 to 11, characterized in that the method, excluding UV light or visible light of the wavelength by which the respective photoredox catalyst is excited, comprises the following steps: i. Dissolving and / or finely dispersing the ingredients in one or more solvent(s) and / or water, ii. Mixing the dissolved or finely dispersed ingredients, iii. Coating a film, foil, layer, carrier, adhesive film, pressure-sensitive adhesive film, preferably a release paper or liner, with the mixture of dissolved or finely divided ingredients according to step 2, iv. Evaporating the solvent and / or water, v. Optionally, winding the reactive adhesive film into a roll.

14. Use of a reactive, pressure-sensitive adhesive film according to one of claims 1 to 10. 11 or a reactive, adhesive tape according to claim 12 for producing bonds on materials selected from plastic, metal, glass or ceramic.

15. Composite body comprising at least two bonding surfaces which are joined together by a hardened adhesive film obtained by light curing of the reactive, adhesive film according to one of the preceding claims 1 to 11 or which are joined together by a hardened adhesive tape obtained by light curing of the reactive, adhesive tape according to claim 12.

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