Reactive adhesive tape

Abstract

The invention relates to a reactive adhesive tape and the use of the adhesive tape for bonding components in electronic, optical or precision mechanical devices, automobiles, medical devices and dental devices. The reactive adhesive tape comprises at least one reactively curable adhesive layer containing a) one or more polymers, and b) at least one first radically polymerizable (meth)acrylate compound, and c) at least one initiator and / or d) at least one redox catalyst, and is characterized in that the at least one first radically polymerizable (meth)acrylate compound is a monomer or oligomer having at least one nitrogen-containing group selected from amide, urethane and urea and the at least one first radically polymerizable (meth)acrylate compound has a melting point of greater than 45 °C and / or a molecular weight of more than 300 g / mol.

Description

[0001] The invention relates to a reactive adhesive tape and the use of the adhesive tape or adhesive tape system for bonding components in electronic devices, automobiles, medical devices and dental devices.

[0002] Reactive pressure-sensitive adhesive tapes, particularly those curing at room temperature, for example based on the polymerization of acrylate monomers, have been developed for several years and have reached a high level of maturity.

[0003] Reactively curable adhesives and adhesive tapes produced from them are described in a number of prior art documents. In this case, a reactive component—particularly based on acrylic monomers—is introduced into a polymer matrix film in the presence of substances that, upon activation, cause the reactive curing of the adhesive, but which, in the stored state (i.e., without activation), do not trigger a reaction. The reaction—for example, polymerization or curing—of the reactive component can be initiated by external influences—such as heat, moisture, plasma, radiation, and so on—or, for example, by bringing two layers of the aforementioned type, one containing an initiator and the other an activator, into direct contact with each other, and the initiator is first activated by the activator. This results in a two-component adhesive system in film form.

[0004] Such two-component adhesive systems based on acrylic monomers in the form of pressure-sensitive adhesive films (adhesive tapes) are described, for example, in WO 2014202402 A1, WO 2015062809 A1, WO 2018104053 A1.

[0005] One-component adhesive films based on acrylic monomers are also well known in the art. These are typically cured with light, especially UV or blue light.

[0006] DE 10 2021 125429 A1, for example, discloses an adhesive film or pressure-sensitive adhesive tape comprising at least one reactive acrylate monomer, an initiator, a photoredox catalyst, (d) a polymer of N-vinyl compounds, and a film-forming polymer. Despite the advantages of the polymer of N-vinyl compounds, it has been shown, however, that these adhesive compositions exhibit weaknesses, particularly in contact with media such as isopropanol-water mixtures.

[0007] However, a major problem is still the storage stability of the uncured adhesive tapes.

[0008] The present invention is therefore based on the object of providing a reactive adhesive tape comprising at least one reactively curable adhesive layer, which has improved storage stability and, in particular, achieves a high bond strength after the curing of previously uncured stored adhesive tapes.

[0009] At the same time, the adhesive strength of the adhesive tape should not be negatively affected before storage.

[0010] The above-mentioned requirements apply not only to adhesive tape in the form of a roll. Instead, smaller die-cuts or elongated die-cuts with a high surface area should also demonstrate good storage stability and high bond strength after curing.

[0011] The object is achieved according to the invention by the reactive adhesive tape according to claim 1.

[0012] The terms "reactively curable adhesive tape" and "reactive adhesive tape" are used synonymously in the context of the present invention. This applies analogously to an adhesive composition and an adhesive layer.

[0013] The reactive adhesive tape according to the invention comprises at least one reactively curable adhesive layer containing a) at least one polymer, and b) at least one first radically polymerizable (meth)acrylate compound, and c) at least one initiator and / or d) at least one redox catalyst, and is characterized in that the at least one first radically polymerizable (meth)acrylate compound is a monomer or oligomer having at least one nitrogen-containing group selected from amide, urethane and urea and the at least one first radically polymerizable (meth)acrylate compound has a melting point of greater than 45 °C and / or a molecular weight of more than 300 g / mol.

[0014] Surprisingly, it has been found that the reactive adhesive tape according to the invention, after curing and bonding to substrates, has a high bond strength even after storage of the still uncured diecuts.

[0015] Surprisingly, it has been found that even smaller diecuts and punched parts with elongated, fine structures (web widths less than 1 cm) and thus a comparatively high surface area with a small adhesive area can be obtained with improved storage stability and continued high adhesive forces and / or bond strengths.

[0016] Without wishing to be bound by theory, "smaller" molecules appear to evaporate easily when dissolved in an adhesive (and no longer in the crystalline state). The inventors have determined that sufficient storage stability is only achieved when the at least one first radically polymerizable (meth)acrylate compound or the monomer or oligomer has a certain size—represented by the molecular weight M or the weight-average molecular weight distribution M w- or the melting point is far enough from room temperature or both.

[0017] In particular, it has surprisingly been found that the improved storage stability can also be achieved with polymers other than acrylates in the film-forming matrix.

[0018] This makes the invention suitable and applicable for a wide range of applications.

[0019] The adhesive tapes according to the invention are particularly suitable for miniaturized applications, such as those required in the electronics industry. Here, it is increasingly important to create very precise and space-saving connections between components.

[0020] The reactive adhesive tape according to the invention is preferably a double-sided adhesive tape. For the sake of simplicity, the adhesive tape according to the invention is also referred to as "adhesive tape" in the double-sided embodiments within the scope of the present invention.

[0021] The present invention relates to an adhesive tape, which can be provided in any desired form, with adhesive tape rolls being preferred. The adhesive tape, particularly in web form, can be produced either in the form of a roll, i.e., wound upon itself in the form of an Archimedean spiral, or as an adhesive strip, such as is obtained, for example, in the form of blanks or diecuts.

[0022] The adhesive tape according to the invention is in particular in web form prior to cutting or punching. A web is understood to be an object whose length (extension in the x-direction) is many times greater than its width (extension in the y-direction), and whose width is approximately, preferably exactly, uniform along the entire length.

[0023] The general term “adhesive tape”, synonymously also called “adhesive strip” or “adhesive film”, encompasses, within the meaning of this invention, all flat structures, such as films or film sections extended in two dimensions, tapes with an extended length and a limited width, tape sections and the like, and ultimately also die-cuts or labels.

[0024] According to advantageous embodiments of the invention, the adhesive tape is in the form of a narrow adhesive tape with a width of less than 1 cm, in particular 200 µm to 1 cm, or as a die-cut product with a web width of less than 1 cm, in particular 200 µm to 1 cm. As explained above, the advantage of improved storage stability achieved according to the invention is particularly effective here.

[0025] In addition to the longitudinal dimension (x-direction) and width (y-direction), the adhesive tape also has a thickness (z-direction) running perpendicular to both dimensions, with the width and longitudinal dimensions being many times greater than the thickness. The thickness is as uniform as possible across the entire surface area of the adhesive tape, determined by its length and width, and preferably exactly the same within tolerances.

[0026] It is understood that the individual layers are arranged one on top of the other along the z-direction.

[0027] All statements of the description apply to the reactive adhesive tape according to the invention, the reactive adhesive tape system according to the invention, the process according to the invention for producing the adhesive tape, the process according to the invention for producing the adhesive tape system, the bonded composite according to the invention, the process according to the invention for producing the bonded composite and the use of the adhesive tape or adhesive tape system according to the invention.

[0028] The invention also encompasses all features that are the subject matter of any dependent patent claims. Furthermore, the invention encompasses combinations of individual features with one another, including combinations of features with varying degrees of preference. 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 encompasses subject matter designated as "embodiments" with varying degrees of preference.

[0029] The adhesive of the reactively curable adhesive layer is described in more detail below.

[0030] The mass of the adhesive layer is a reactively curable adhesive.

[0031] In the context of the present invention, a “reactively curable adhesive” is understood to mean an adhesive which cures by chemical reaction of at least one correspondingly reactive component contained therein and thereby creates the adhesive bond.

[0032] In the context of the present invention, such adhesives are also referred to as “reactive adhesives”.

[0033] The reactive curable adhesive tapes of the invention or the corresponding reactive adhesive compositions preferably function as structural adhesives or semi-structural adhesives after curing. According to DIN EN 923: 2006-01, structural adhesives are adhesives that form adhesive bonds that can maintain a specified strength in a structure for a specified, extended period of time (according to the ASTM definition: "bonding agents used for transferring required loads between adherends exposed to service environments typical for the structure involved"). They are therefore adhesives for bonds subject to high chemical and physical stresses that contribute to the strengthening of the adhesive tapes when cured.

[0034] The term "(semi-)structural adhesive" or "(semi-)structural adhesives" encompasses "semi-structural adhesives" and "structural adhesives." "Semi-structural adhesives" are those cured adhesives that exhibit a tensile shear strength of at least 1.0 MPa and more preferably at least about 1.5 MPa (each on steel) in the tensile shear test. "Structural adhesives" or "structural adhesives" are those cured adhesives that exhibit a particularly high tensile shear strength and that exhibit a tensile shear strength of at least 5 MPa, more preferably at least 7 MPa, and particularly preferably at least 10 MPa (each on steel) in the tensile shear test.

[0035] As stated at the beginning, the chemical reaction occurs after activation, such as by heat, moisture, plasma, radiation or by bringing two adhesive layers containing suitable reactants into contact.

[0036] In the context of the present invention, preference is given to reactively curable adhesive tapes in which curing takes place by activation by means of radiation, in particular by means of light of a wavelength in the visible range of the electromagnetic spectrum or by means of UV light, or by activation by bringing into contact with a further reactively curable adhesive layer or a corresponding reactively curable adhesive tape.

[0037] The adhesive of the reactively curable adhesive layer D contains at least a) at least one polymer, and b) at least one first radically polymerizable (meth)acrylate compound, and c) at least one initiator and / or d) at least one redox catalyst, wherein the at least one first radically polymerizable (meth)acrylate compound is a monomer or oligomer having at least one nitrogen-containing group selected from amide, urethane and urea, and the at least one first radically polymerizable (meth)acrylate compound has a melting point of greater than 45 °C and / or a molecular weight of more than 300 g / mol.

[0038] The total mass of the components of the adhesive mass amounts to 100 percent by weight (wt%).

[0039] The quantities of components a) to d) in percent by weight refer to the total weight of the adhesive.

[0040] Furthermore, the amount of any additives contained, as described below, is also counted towards the 100% by weight of the adhesive.

[0041] Any other optional components, such as solvents or water, are used solely for manufacturing purposes and are not included in the total weight of the adhesive components in this analysis. This also applies to solvents that may already be contained in the commercially available raw materials. a) Polymer

[0042] The reactive adhesive contains at least one polymer.

[0043] It may contain one (single) polymer or multiple polymers. The definition of "polymer," as well as the term "total amount," encompasses both the presence of a single polymer and the presence of multiple polymers. The terms "at least one," "one or more," or "exactly one" refer, as is customary in the industry, to the chemical nature of the respective compounds and not to their quantity.

[0044] The adhesive preferably comprises 10 wt.% to 70 wt.% of at least one polymer a), particularly preferably the adhesive comprises 25 wt.% to 62 wt.%, again preferably 30 to 62 wt.%, and according to exemplary embodiments preferably 40 wt.% to 60 wt.%, of at least one polymer a), in each case based on the total mass of the base mass.

[0045] The weight percentages (wt%) refer to one polymer or to the sum of all polymers if two or more polymers are present.

[0046] As already explained, the invention has surprisingly succeeded in providing different adhesive tapes each containing different polymers as film formers.

[0047] According to preferred embodiments of the invention, the polymer is selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), poly(meth)acrylates, polyurethanes (PU), polyvinyl acetates (PVA), polyvinyl alcohols, polyvinyl acetals, such as in particular polyvinyl butyral (PVB), polyesters and polymers of monomers comprising N-vinyl compounds.

[0048] Particularly preferably, it is selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), polyvinyl acetates (PVA), poly(meth)acrylates, poly(N-vinylcaprolactam), poly(N-vinylpyrrolidone) and polyurethanes (PU).

[0049] According to particularly preferred embodiments, the adhesive contains at least one poly(meth)acrylate. The base composition preferably contains 10 wt.% to 70 wt.%, particularly preferably 25 wt.% to 62 wt.%, and especially preferably 30 wt.% to 62 wt.%, of poly(meth)acrylate.

[0050] A "poly(meth)acrylate" is understood to mean a polymer obtainable by polymerization, for example, radical polymerization, of acrylic and / or methacrylic monomers and optionally other copolymerizable monomers. In particular, a "poly(meth)acrylate" is understood to mean a polymer whose monomer base consists of at least 50 wt. % acrylic acid, methacrylic acid, acrylic esters, and / or methacrylic esters, with acrylic esters and / or methacrylic esters being present at least proportionally, preferably at least 30 wt. %, based on the total monomer base of the polymer in question.

[0051] The adhesive preferably contains at least one poly(meth)acrylate; it may therefore contain one or more poly(meth)acrylates. The terms "at least one," "one or more," or even "exactly one" refer herein, as is customary in the industry, to the chemical nature of the respective compounds and not to their quantity. This also applies to the monomer composition of the poly(meth)acrylate.

[0052] For example, the monomer composition may comprise exclusively n-butyl acrylate as a monomer, which would mean that the monomer composition comprises a plurality of n-butyl acrylate molecules.

[0053] The poly(meth)acrylate(s) can in principle be any poly(meth)acrylate.

[0054] According to preferred embodiments of the invention, the poly(meth)acrylates contained can be prepared by polymerizing a monomer composition containing one or more monomers selected from the group consisting of ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, iso-amyl acrylate, n-hexyl acrylate, 2-heptyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, iso-octyl acrylate, n-nonyl acrylate, isononyl acrylate, n-decyl acrylate, isodecyl acrylate, 2-[[(butylamino)carbonyl]oxy]ethyl acrylate, 2-cyanoethyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-phenoxyethyl acrylate, isostearyl acrylate, Docosyl acrylate, 2-[2-(2-methoxyethoxy)-ethoxy]ethyl acrylate, isobornyl acrylate, norbornyl acrylate, benzyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, cyclohexyl acrylate, 1-acryloyloxy-3-hydroxyadamantane, 4-[(6-acryloyloxy)hexyloxy]4'-cyanobiphenyl, N-succinimidyl acrylate, 1-ethylcyclopentyl acrylate, N-tert-octylacrylamide, N-tert-butylacrylamide,Dimethylacrylamid, Diethylacrylamid, N-iso-Propylacrylamid, N-Hydroxyethylacrylamid, Acrylamid, 2-Acrylamido-2-methylpropansulfonsäure, N-[3-(Dimethylamino)propyl]acrylamid, Diacetonacrylamid, N-(Butoxymethyl)acrylamid, N-Phenylacrylamid, N-[2-(Dimethylamino)ethyl]acrylamid, N-[2-(Diethylamino)ethyl]acrylamid, Methylmethacrylat, Ethylmethacrylat, Cyclohexylmethacrylat, Benzylmethacrylat, Isobornylmethacrylat, Glycerolformalmethacrylat, 2-Dimethylaminoethylmethacrylat, Phenoxyethylmethacrylat, 9-Anthrylmethylmethacrylat, 2-Ethyl-2-adamantylmethacrylat, 2-(Acetoacetyloxy)ethylmethacrylat, 2-Isopropyl-2-methacryloyloxyadamantan, iso-Propylmethacrylat, iso-Butylmethacrylat, tert-Butylmethacrylat, Furfurylmethacrylat, 2-Methacryloyloxy-2-methyladamantan, 2-Morpholinoethylmethacrylat, Phenylmethacrylat, N-Succinimidylmethacrylat, 2-(tert-Butylamino)ethylmethacrylat, 2-Cyclohexylpropan-2-yl-methacrylat, 1-Adamantylmethacrylat, 1-Methylcyclopentylmethacrylat, N-tert-Butylmethacrylamid,N-(Methoxymethyl)methacrylamid, N,N-Dimethylmethacrylamid, Methacrylamid, N-Phenylmethacrylamid, N,N-Dimethylmethacrylamid, N-iso-Propylmethacrylamid, N-Vinylformamid, N-Vinylpyrrolidon, N-Vinylcaprolactam, N-Vinylcarbazol, N-Vinylimidazol, Vinylmethyloxazolidinon, N-Vinyl-N-methylacetamid, Hydroxyethylacrylat, Hydroxypropylacrylat, 4-Hydroxybutylacrylat, 2-Hydroxy-3-phenoxypropylacrylate, Hydroxyethylmethacrylat, Hydroxypropylmethacrylat, 4-Hydroxybutylmethacrylat, 2-Hydroxy-3-phenoxypropylmethacrylat, 4-Hydrxyethylacrylamid, Acrylsäure, Methacrylsäure, 2-Acryloyloxyethylsuccinat, Methacryloxyethylsuccinat, Sulfoethylmethacrylat, Methacrylamid, Glycidylacrylat, Glycidylmethacrylat, 3,4-Epoxycyclohexylmethylacrylat, 3,4-Epoxycyclohexylmethylmethacrylat, 4-Hydroxybutylacrylateglycidylether, 4-Hydroxybutylmethacrylateglycidylether, Isocyanatoethylacrylat, Isocyanatoethylmethacrylat, 2-[2-(Methacryloyloxy)ethyloxy]ethylisocyanat, 2-[2-(Acryloyloxy)ethyloxy]ethylisocyanat und α,α-Dimethyl-m-isopropenylbenzyl isocyanate.,

[0055] According to preferred embodiments, the poly(meth)acrylates contained can be prepared by polymerizing a monomer composition containing 2-phenoxyethyl acrylate (PEA) or benzyl (meth)acrylate and methyl methacrylate (MMA) as monomers.

[0056] According to preferred embodiments, at least one poly(meth)acrylate is present which can be prepared by polymerizing a monomer composition which has at least 15% by weight, preferably at least 30% by weight, of monomers having an aromatic radical.

[0057] The aromatic radical of the AR groups is preferably selected from the group consisting of phenyl groups, phenylene groups, benzyl groups, naphthyl groups, and naphthylene groups, which may optionally bear substituents. The aromatic radical AR is particularly preferably selected from the group consisting of phenyl groups, phenylene groups, naphthyl groups, and naphthylene groups, with phenyl groups or phenylene groups being very particularly preferred.

[0058] In accordance with the understanding of the person skilled in the art, a “phenylene group” is understood to mean a phenyl group which is at least doubly bonded.

[0059] This applies analogously to naphthylene.

[0060] In particular, the monomers having an aromatic radical are selected from the group consisting of benzyl acrylate, phenyl acrylate, 2-phenylethyl acrylate, 3-phenylpropyl acrylate, 4-phenylbutyl acrylate, 5-phenylpentyl acrylate, 6-phenylhexyl acrylate, benzyl methyl acrylate, phenyl methacrylate, 2-phenylethyl methacrylate, 3-phenylpropyl methacrylate, 4-phenylbutyl methacrylate, 5-phenylpentyl methacrylate, 6-phenylhexyl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxydiethylene glycol acrylate, 2-phenoxytriethylene glycol acrylate, 2-phenoxytetraethylene glycol acrylate, 2-phenoxypentaethylene glycol acrylate, 2-phenoxyhexaethylene glycol acrylate, 2-phenoxyheptaethylene glycol acrylate, 2-phenoxyoctaethylene glycol acrylate, 2-phenoxynonaethylene glycol acrylate, 2-phenoxydecaethylene glycol acrylate, 2-phenoxyethyl methacrylate, 2-phenoxydiethylene glycol methacrylate, 2-phenoxytriethylene glycol methacrylate, 2-phenoxytetraethylene glycol methacrylate, 2-phenoxypentaethylene glycol methacrylate, 2-Phenoxyhexaethylene glycol methacrylate,2-Phenoxyheptaethyleneglycolmethacrylat, 2-Phenoxyoctaethyleneglycolmethacrylat, 2-Phenoxynonaethyleneglycolmethacrylat, 2-Phenoxydecaethyleneglycolmethacrylat, 4-tert.-Butylphenylacrylat, 4-tert.-Butylphenylmethacrylat, 2-(4-tert.-Butyl)phenoxyethylacrylat, 2-(4-tert.-Butyl)phenoxydiethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxytriethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxytetraethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxypentaethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxyhexaethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxyheptaethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxyoctaethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxynonaethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxydecaethyleneglycolacrylat, 2-(4-tert.-Butyl)phenoxyethylmethacrylat, 2-(4-tert.-Butyl)phenoxydiethyleneglycolmethacrylat, 2-(4-tert.-Butyl)phenoxytriethyleneglycolmethacrylat, 2-(4-tert.-Butyl)phenoxytetraethyleneglycolmethacrylat, 2-(4-tert.-Butyl)phenoxypentaethyleneglycolmethacrylat,2-(4-tert-butyl)phenoxyhexaethylene glycol methacrylate, 2-(4-tert-butyl)phenoxyheptaethylene glycol methacrylate, 2-(4-tert-butyl)phenoxyoctaethylene glycol methacrylate, 2-(4-tert-butyl)phenoxynonaethylene glycol methacrylate, 2-(4-tert-butyl)phenoxydecaethylene glycol methacrylate.,

[0061] Particularly preferred monomers are those having an aromatic radical selected from the group consisting of benzyl acrylate, phenyl acrylate, benzyl methacrylate, phenyl methacrylate, 2-phenoxyethyl acrylate, and 2-phenoxyethyl methacrylate. Most preferred monomers are those selected from benzyl acrylate and benzyl methacrylate.

[0062] According to further particularly preferred embodiments, the adhesive contains at least one polyurethane. The base composition preferably contains 10 wt.% to 60 wt.%, particularly preferably 25 wt.% to 60 wt.%, and especially preferably 50 wt.% to 60 wt.%, of polyurethane.

[0063] Thermoplastic polyurethanes with a crystalline melting temperature of less than 100°C and / or a softening temperature of less than 100°C are preferred. In this context, the term "softening temperature" refers to the temperature at which the thermoplastic granules bond to themselves. If the polymer is a semicrystalline thermoplastic polymer, then, in addition to its softening temperature (which is related to the melting of the crystallites), it very preferably has a glass transition temperature of at most 25°C, preferably at most 0°C.

[0064] According to preferred embodiments, at least one thermoplastic polyurethane is used. Commercially available thermoplastic polyurethanes include Desmocoll ® 530 / 1 and Desmocoll ® 540 / 3 and 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. There are also the Elastollan product lines. ® from BASF (Ludwigshafen, Germany) or Pearlbond from Lubrizol (Lubrizol Advanced Materials Europe BVBA, Brussels, Belgium).

[0065] The thermoplastic polyurethane preferably has a softening temperature of less than 100 °C, in particular less than 80 °C. Preferred examples of such thermoplastic polyurethanes are Desmomelt ® 530 and IROSTIC ® S-6558-06. Desmomelt ® 530 is a hydroxy-terminated, largely linear, thermoplastic, highly crystallizing polyurethane elastomer. IROSTIC ®According to the manufacturer, S-6558-06 is a linear thermoplastic polyurethane for solvent-based adhesives. Its characteristics include: very low crystallization rate, long open time, and very low activation temperature.

[0066] According to further particularly preferred embodiments, the adhesive contains at least one polyvinyl acetate.

[0067] The adhesive preferably contains 5 wt.% to 65 wt.%, particularly preferably 25 wt.% to 62 wt.%, especially preferably 50 wt.% to 62 wt.%, of polyvinyl acetates.

[0068] According to further particularly preferred embodiments, the adhesive contains at least one ethylene-vinyl acetate copolymer.

[0069] The adhesive preferably contains 5 wt.% to 60 wt.%, particularly preferably 25 wt.% to 50 wt.%, especially preferably 30 wt.% to 50 wt.%, of ethylene-vinyl acetate copolymers.

[0070] According to preferred embodiments, the at least one ethylene-vinyl acetate copolymer has a vinyl acetate content of 60 to 100%. A suitable ethylene-vinyl acetate copolymer is available, for example, under the trade name Levamelt ® 700 available from Arlanxeo.

[0071] According to preferred embodiments of the invention, the polymer, in particular and for example poly(meth)acrylate, of the reactive adhesive in the reactive adhesive tape according to the invention is essentially inert toward the at least one first radically polymerizable (meth)acrylate compound and any further radically polymerizable (meth)acrylate compounds present, the initiator system, and any other substances present. In this context, "inert" means that the radically polymerizable (meth)acrylate compounds, the initiator system, and any other substances present essentially do not react with the polymer prior to light curing under suitably selected conditions, in particular at room temperature (23°C).

[0072] For this reason, in a preferred embodiment, no acid, in particular no acrylic acid or other monomers having one or more carboxyl groups, and no amines, in particular no tertiary amines, are contained as comonomer(s) in the monomer composition of the polymer or poly(meth)acrylate.

[0073] The polymer(s) contained preferably do not have a primary, secondary or tertiary amino group.

[0074] In a special embodiment, the poly(meth)acrylate(s) is / are also inert after activation of the curing reaction. This means that the poly(meth)acrylate does not react in the radical reaction. b) radically polymerizable (meth)acrylate compound

[0075] The reactive adhesive of the reactive adhesive tape according to the invention comprises at least one first radically polymerizable (meth)acrylate compound b), wherein the at least one first radically polymerizable (meth)acrylate compound is a monomer or oligomer having at least one nitrogen-containing group selected from amide, urethane and urea.

[0076] Furthermore, the at least one first radically polymerizable (meth)acrylate compound has a melting point of greater than 45 °C and / or a molecular weight of more than 300 g / mol.

[0077] According to a first alternative, the at least one first radically polymerizable (meth)acrylate compound thus has a melting point of greater than 45 °C, preferably of at least 50 °C, and particularly preferably of at least 55 °C.

[0078] The melting point is determined according to the method listed in the Methods section.

[0079] According to a second alternative, the at least one first radically polymerizable (meth)acrylate compound has a molecular weight of more than 300 g / mol, preferably more than 400 g / mol, most preferably more than 500 g / mol.

[0080] In a third alternative, the invention also encompasses the fact that the at least one first radically polymerizable (meth)acrylate compound has a melting point of greater than 45 °C and a molecular weight of more than 300 g / mol, wherein here too the preference levels for M and M w and the melting point are independent of each other.

[0081] In the case of radically polymerizable (meth)acrylate compounds, which exist as a mixture of oligomers or generally as a mixture of different molecules with different molecular weights, the weight average of the molecular weight distribution M w the molecular weight M

[0082] In the event that such an oligomer mixture is used and in particular the melting point is 45°C or less, the mixture preferably contains no molecule having a molecular weight of 300 g / mol or less, whereby solvents or other accompanying substances are not taken into account here. It is crucial that such a mixture preferably does not contain a first - in the context of the present invention nitrogen-containing - radically polymerizable (meth)acrylate compound having a molecular weight of 300 g / mol or less, or at least 95% by weight - based on the total weight of the oligomer mixture - of the radically polymerizable (meth)acrylate compounds in such a mixture have a molecular weight of more than 300 g / mol.

[0083] The upper limit for the molecular weight of the at least one first radically polymerizable (meth)acrylate compound is preferably 35,000 g / mol and is in particular less than 15,000 g / mol, in particular less than 10,000 g / mol.

[0084] It has been found that sufficient storage stability is only achieved if at least one of the above-mentioned conditions - melting point or lower limit for the molecular weight of the first nitrogen-containing radically polymerizable (meth)acrylate compound - is met.

[0085] The at least one nitrogen-containing group is preferably selected from amide and urethane groups. The nitrogen-containing group is particularly preferably a urethane group.

[0086] Amines are not included in the selection of the nitrogen-containing group.

[0087] Thus, the at least one first radically polymerizable (meth)acrylate compound preferably does not contain an amine group. This applies to primary, secondary, and tertiary amines.

[0088] In accordance with the understanding of those skilled in the art, the at least one first radically polymerizable (meth)acrylate compound or the monomer or oligomer is intended to represent a monomer or oligomer capable of radical chain polymerization. A suitable radically polymerizable monomer or oligomer is selected from the group consisting of acrylic acid esters, methacrylic acid esters, and crosslinking radically polymerizable monomers such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, and higher-functionality acrylates or higher-functionality methacrylates, wherein the compounds are functionalized according to the invention with at least one nitrogen-containing group.

[0089] The term radically polymerizable oligomers is understood by the person skilled in the art, in particular in contrast to polymers, to mean radically polymerizable compounds with a weight-average molecular weight distribution M w of less than 35,000 g / mol, in particular less than 15,000 g / mol, in particular less than 10,000 g / mol, and in the context of the present invention in particular so-called urethane acrylates containing ether oligomers, butadiene oligomers, ester oligomers, carbonate oligomers, silicone oligomers, with a weight average molecular weight distribution M w of less than 35,000 g / mol, in particular less than 15,000 g / mol, in particular less than 10,000 g / mol, wherein the oligomers additionally each have at least one nitrogen-containing group as required by the invention.

[0090] These include, among others, aliphatic, aromatic and silicone urethane (meth)acrylates, aliphatic and aromatic polyester (meth)acrylates, polybutadiene (meth)acrylates, dendritic (meth)acrylates, polyether (meth)acrylates and polycarbonate (meth)acrylates available for example from Miwon and Bomar, such as MIRAMER SC2565 with a Mw of 5200 g / mol from Miwon, or oligomers based on aliphatic polyurethanes, in particular based on polyester polyurethanes, such as the aliphatic urethane diacrylates available under the trade names EBECRYL® 8402, EBECRYL® 4858 or EBECRYL® 8809, or acrylated oligoesters, for example based on caprolactones, such as the commercially available hydroxyethyl caprolactone acrylate (HECLA; CAS No.: 110489-05-9).

[0091] The functionality of the polymerizable oligomers, i.e. the number of radically polymerizable groups per molecule, is preferably 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 Pas, but particularly preferably significantly above 10 Pas. Oligomers with dynamic viscosities at 25°C of greater than 20 Pas, preferably greater than 30 Pas, are particularly suitable for producing good pressure-sensitive adhesives with sufficient cohesion. In the context 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 certainly.

[0092] According to particularly preferred embodiments of the invention, at least one (meth)acrylate-containing oligomer based on aliphatic polyurethanes, in particular based on polyester polyurethanes, is present as the first radically polymerizable (meth)acrylate compound, such as, for example, the aliphatic urethane diacrylate available under the trade name EBECRYL® 8402.

[0093] This achieves particularly high storage stability.

[0094] Preferred monomers with regard to high bond strength are acrylic acid esters and / or methacrylic acid esters in which the alcohol part of the ester contains functional groups and, according to the invention, at least one nitrogen-containing group.

[0095] Examples of preferred monomers as the first radically polymerizable (meth)acrylate compound are 2-methacryloxyethylphenyl urethane (MAPU; CAS No.: 51727-47-0), 2-[[(Butylamino)carbonyl]oxy]ethyl acrylate (CAS No.: 63225-53-6), diurethane dimethacrylate (isomer mixture) (CAS No.: 72869-86-4).

[0096] According to particularly preferred embodiments of the invention, at least the monomer 2-methacryloxyethylphenyl urethane (MAPU) is present as the first radically polymerizable (meth)acrylate compound. This achieves particularly high storage stability.

[0097] MAPU appears to work particularly well in small-sized die-cuts. Without being bound by theory, it is speculated that these monomers have a positive effect on the inhibition caused by atmospheric oxygen.

[0098] According to advantageous embodiments, the adhesive contains at least one second radically polymerizable (meth)acrylate compound which is a monomer or oligomer having at least one hydroxyl group.

[0099] Preferably, as the second radically polymerizable (meth)acrylate compound, at least one monomer or oligomer is included which is selected from the group consisting of hydroxyethylcaprolactone acrylate (HECLA), 2-hydroxy-3-phenoxypropyl acrylate (HPPA) and 2,3-dihydroxypropyl methacrylate.

[0100] Particularly preferably, at least hydroxyethylcaprolactone acrylate (HECLA) is present as the second radically polymerizable (meth)acrylate compound.

[0101] This achieves particularly high storage stability.

[0102] According to preferred embodiments, the monomers and oligomers mentioned can also be used in combination with one another.

[0103] According to particularly preferred embodiments, the adhesive contains the reactively curable adhesive layer as the first radically polymerizable (meth)acrylate compound at least the monomer 2-methacryloxyethylphenyl urethane (MAPU) and as the second radically polymerizable (meth)acrylate compound at least hydroxyethylcaprolactone acrylate (HECLA).

[0104] This achieves particularly high storage stability and high bond strengths. According to further particularly preferred embodiments, the adhesive contains the reactively curable adhesive layer as the first radically polymerizable (meth)acrylate compound, at least the monomer 2-methacryloxyethylphenyl urethane (MAPU) and at least one (meth)acrylate-containing oligomer based on aliphatic polyurethanes, in particular based on polyester polyurethanes, such as the aliphatic urethane diacrylate available under the trade name EBECRYL® 8402, and as the second radically polymerizable (meth)acrylate compound, at least hydroxyethylcaprolactone acrylate (HECLA).

[0105] This achieves particularly high storage stability and high bonding strengths.

[0106] According to further particularly preferred embodiments, the adhesive contains the reactively curable adhesive layer as the first radically polymerizable (meth)acrylate compound at least one (meth)acrylate-containing oligomer based on aliphatic polyurethanes, in particular based on polyester polyurethanes, such as the aliphatic urethane diacrylate available under the trade name EBECRYL® 8402, and as the second radically polymerizable (meth)acrylate compound at least hydroxyethylcaprolactone acrylate (HECLA).

[0107] This achieves particularly high storage stability and high bonding strengths.

[0108] Furthermore, the reactively curable adhesive may contain other radically polymerizable monomers or oligomers.

[0109] However, it is preferred not to contain any polymerizable (meth)acrylate compound containing an amine group. This applies to primary, secondary, and tertiary amines.

[0110] Furthermore, it preferably does not contain any acid.

[0111] This means that no amine or acid is preferably added during the production of the adhesive.

[0112] The reactive adhesive of the reactive adhesive tape according to the invention preferably contains 10 wt.% to 50 wt.%, particularly preferably 10 to 40 wt.%, of the at least one first radically polymerizable (meth)acrylate compound.

[0113] In the event that at least one second radically polymerizable (meth)acrylate compound is present, it is preferably present in an amount of 5 to 40, particularly preferably 10 to 38 wt.%, again preferably 13 to 38 wt.%.

[0114] The stated weight percentages refer to the total mass of all first and second radically polymerizable (meth)acrylate compounds.

[0115] If, for example, two different first radically polymerizable (meth)acrylate compounds are present, their total mass is preferably 10 wt.% to 50 wt.%, particularly preferably 10 to 40 wt.%.

[0116] The total mass of first and second radically polymerizable (meth)acrylate compounds contained in the adhesive is preferably 10 to 65 wt.%, particularly preferably 20 to 62 wt.%, very particularly preferably 30 to 62 wt.%.

[0117] If further radically polymerizable monomers or oligomers are present which are not to be understood as first or second monomer or oligomer within the meaning of the present invention, the total mass of all radically polymerizable monomers or oligomers present in the adhesive is preferably likewise 10 to 65% by weight, particularly preferably 20 to 62% by weight, very particularly preferably 30 to 62% by weight.

[0118] Preferably, in the reactive adhesive of the reactive adhesive tape according to the invention, the weight ratio of the totality of the polymers to the totality of the radically polymerizable monomers or oligomers is 3:1 to 1:3, more preferably 2:1 to 1:2, in particular 2:1 to 1:1. c) Initiator and / or d) Redox catalyst

[0119] The adhesive contains c) at least one initiator and / or d) at least one redox catalyst.

[0120] These components represent, in particular, an initiator system that triggers or activates the reaction for curing the reactive adhesive. Depending on the type of activation, different initiators and redox catalysts are suitable.

[0121] According to preferred embodiments, the reactive adhesive tape according to the invention is characterized in that the at least one reactively curable adhesive layer is a light-curing adhesive layer and contains c) at least one initiator and d) at least one redox catalyst, wherein the redox catalyst is a photoredox catalyst.

[0122] In the context of the present invention, the term "initiator," in particular "radical initiator" or radical-forming substance (or also hardener), refers to a compound that can initiate a polymerization reaction or crosslinking of the adhesive. However, the initiator, in particular radical initiator, participates only to a very small extent in the reaction and therefore does not form a polymer component that determines the properties of the bond.

[0123] The initiator is preferably a radical initiator, although a mixture of two or more initiators is also conceivable. Any radical initiator known in the art can be used. Preferred radical initiators are peroxides, hydroperoxides, and azo compounds.

[0124] According to particularly preferred embodiments of the invention, the radical initiator is an organic peroxide. Hydroperoxides are particularly preferred, in particular diisopropylbenzene hydroperoxide (CAS No. 26762-93-6). Diisopropylbenzene hydroperoxide is preferably used in the form of a 50 wt.% solution of diisopropyl hydroperoxide in diisopropylbenzene, available under the trade name Peroxan® IHP-50. α,α-Dimethylbenzyl hydroperoxide, also known as cumene hydroperoxide (CAS No. 80-15-9), can also be used. Furthermore, for example, p-menthane hydroperoxide (CAS No. 26762-92-5), tert-amyl hydroperoxide (CAS No. 3425-61-4) or 1,1,3,3-tetramethylbutyl hydroperoxide (CAS No. 5809-08-5) can also be used.

[0125] The adhesive preferably contains 0.1 wt.% to 9 wt.%, particularly preferably from 0.1 wt.% to 5 wt.%, and particularly preferably from 0.1 wt.% to 2 wt.%, of initiator.

[0126] In the context of the present invention, the term “redox catalyst” refers to a compound that can mediate the transfer of electrons between chemical compounds that would otherwise react more slowly or not at all.

[0127] In the context of the present invention, the term "photoredox catalyst" refers to a light- or UV-sensitive compound which, 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. In contrast to a photoinitiator, a photoredox catalyst does not decompose into reactive cleavage products upon irradiation with light or UV light, but is merely placed in an excited state which is generally relatively long-lasting and from which redox processes can be initiated or mediated. The photoredox catalyst preferably does not trigger polymerization in the mixture with the radically polymerizable monomers or oligomers at temperatures up to 90 °C, even when the mixture is irradiated with UV or blue light. This applies as long as no radical initiator or other initiating substance is added to the mixture.The photoredox catalyst is therefore not an initiator or radical initiator. When irradiated with UV or blue light, it merely activates the initiator, which then triggers polymerization.

[0128] However, in the context of the present invention, the terms “redox catalyst” and “photoredox catalyst” should not be limited to the fact that the respective compound is not consumed in the course of the reaction.

[0129] Photoredox catalysts known to those skilled in the art can be used as photoredox catalysts. Photoredox catalysts are often transition metal complexes, which, depending on the ligand, are neutral or present as a cation, with ruthenium, copper, or iridium as the central atom. Preferred ligands of the transition metal complex are bidentate ligands, in particular those with at least two interconnected heteroaromatic six-membered rings, for example in the form of a biphenyl, which in turn can be part of a more complex structure—such as polycyclic aromatic hydrocarbons and / or bridged bicyclic or polycyclic aromatic hydrocarbons. If ligands containing biphenyl structural units are used, one of the aromatic rings of the biphenyl can advantageously form a "tooth" of the ligand, thus resulting in bidentateness.Bicyclic aromatic compounds—such as biphenyl compounds—or polycyclic aromatic compounds as ligands can be unsubstituted—i.e., they carry a hydrogen atom at each C atom—or mono- or polysubstituted. The transition metal complex acts as a photoredox catalyst within the meaning of the present invention.

[0130] According to preferred embodiments of the invention, the photoredox catalyst is a transition metal complex with ruthenium as the central atom and bipyridine or a mono- or polysubstituted bipyridine derivative as ligand.

[0131] In a further preferred embodiment of the invention, the photoredox catalyst is a transition metal complex with iridium as the central atom and phenylpyridine or a mono- or polysubstituted phenylpyridine derivative as the ligand.

[0132] A reactive adhesive tape according to the invention according to the above embodiments is therefore also preferred, which is characterized in that the photoredox catalyst contains ruthenium as the central atom and bipyridine or a mono- or polysubstituted bipyridine derivative as the ligand, or Iridium as the central atom and phenylpyridine or a mono- or polysubstituted phenylpyridine derivative as ligand.

[0133] Preferably, the at least one photoredox catalyst is selected from the group consisting of Ru(bpm) 2+ (e.g. Tris(2,2'-bipyrimidine)ruthenium(II) dichloride), Ru(bpz)3 2+ (e.g. Tris(2,2'-bipyrazine)ruthenium bis(hexafluorophosphate)), Ru(bpy)3 2+ , Ru(phen)3 2+ (e.g. Dichloro tris(1,10-phenanthroline)ruthenium(II) chloride), Ir[dF(CF3)ppy]2(dtbbpy) +(e.g. [4,4'-bis(1,1-dimethylethyl)-2,2'-bipyridine-N1,N1']bis[3,5-difluoro-2-[5-(trifluoromethyl)-2-pyridinyl-N]phenyl-C]iridium(III) hexafluorophosphate), Ir(ppy)2(dtbbpy) + (e.g. [Ir(dtbbpy)(ppy)2][PF6]), each plus one or more anions (or counterion(s) of the cation), such as chloride or hexafluorophosphate, Ir(Fppy)3 or fac-Ir(ppy)3 (fac-tris(2-phenylpyridine)iridium(III)), Ir(ppy)3, and the copper complex dichloro-(1,10-phenanthroline)-copper(II) (CAS: 14783-09-6).

[0134] According to particularly preferred embodiments of the invention, the photoredox catalyst is tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate, Ru(bpy)sCl2 · 6H2O.

[0135] The adhesive preferably contains up to 1 wt.%, particularly preferably from 0.01 wt.% to 0.5 wt.%, and particularly preferably from 0.01 wt.% to 0.1 wt.%, of redox catalyst. Other additives and / or auxiliary materials

[0136] The adhesive may optionally contain further additives and / or auxiliaries known in the art. The proportion of the further additives and / or auxiliaries may range from 0 wt.% to about 20 wt.%, preferably from 0 wt.% to about 15 wt.%, more preferably from 0 wt.% to about 10 wt.%, and most preferably from 0 wt.% to about 5 wt.%.

[0137] Other additives and / or auxiliaries include, for example, fillers, 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 anti-aging, light and UV protection agents, for example in the form of primary and secondary antioxidants.

[0138] In particular and according to preferred embodiments, the proportion of fillers, such as glass beads or SiLibeads® 5211, is up to 50 wt.%, in particular up to 40 wt.%.

[0139] According to preferred embodiments, the reactive adhesive contains at least one rheology-modifying filler, such as in particular silica, preferably in an amount of 1 to 10 wt.%, particularly preferably 2 to 5 wt.%. Adhesive adhesion

[0140] Preferably, the reactively curable adhesive of the adhesive layer is pressure-sensitive and thus preferably a pressure-sensitive adhesive and the adhesive layer is therefore preferably a pressure-sensitive adhesive layer.

[0141] This facilitates the processability and application of the adhesive tape, particularly in embodiments in which the adhesive layer is used as a transfer adhesive tape.

[0142] The adhesive strength allows reliable and safe application of the reactive pressure-sensitive adhesive tapes to the substrate before curing.

[0143] In the present invention, a pressure-sensitive adhesive is understood, as is generally customary, to be a substance that is permanently tacky and adhesive, particularly at room temperature. A characteristic of a pressure-sensitive adhesive is that it can be applied to a substrate by pressure and remains adhered there, whereby the pressure to be applied and the duration of this pressure are not further defined. In some cases, depending on the exact type of pressure-sensitive adhesive, the temperature and humidity, as well as the substrate, the application of short-term, minimal pressure, which does not go beyond a light touch for a brief moment, is sufficient to achieve the adhesive effect; in other cases, a longer exposure to high pressure may be necessary.

[0144] Pressure-sensitive adhesives have special, characteristic viscoelastic properties that lead to their permanent tack and adhesive strength. They are characterized by the fact that, when mechanically deformed, both viscous flow processes and the development of elastic restoring forces occur. The respective proportions of both processes are in a specific relationship to each other, depending on the precise composition, structure, and degree of crosslinking of the pressure-sensitive adhesive, as well as the speed and duration of the deformation and the temperature.

[0145] The viscous flow component is necessary to achieve adhesion. Only the viscous components, caused by macromolecules with relatively high mobility, enable good wetting and flow onto the substrate to be bonded. A high proportion of viscous flow leads to high pressure-sensitive adhesion (also referred to as tack or surface stickiness) and thus often also to high adhesive strength. Highly cross-linked systems, crystalline, or glass-like polymers, are generally not or at least only slightly tacky due to the lack of flowable components.

[0146] The proportional elastic restoring forces are necessary to achieve cohesion. They are caused, for example, by very long-chain and highly entangled macromolecules, as well as by physically or chemically cross-linked macromolecules, and enable the transfer of forces acting on an adhesive bond. They ensure that an adhesive bond can adequately withstand continuous loading, for example, in the form of permanent shear stress, over an extended period of time.

[0147] For a more precise description and quantification of the degree of elastic and viscous components, as well as the relationship between the components, the storage modulus (G') and loss modulus (G''), which can be determined using Dynamic Mechanical Analysis (DMA, according to DIN EN ISO 6721), can be used. G' is a measure of the elastic component, G'' a measure of the viscous component of a material. Both parameters depend on the deformation frequency and the temperature.

[0148] These parameters can be determined using a rheometer. The material under test is subjected to a sinusoidal oscillating shear stress, for example, in a plate-on-plate arrangement. Shear stress-controlled devices measure the deformation as a function of time and the temporal offset of this deformation relative to the application of the shear stress. This temporal offset is referred to as the phase angle δ.

[0149] The storage modulus G' is defined as follows: G'=(τ / γ)⋅cos(δ)(τ=shear stress, γ=deformation, δ=phase angle=phase shift between shear stress and deformation vector).

[0150] The definition of the loss modulus G'' is: G"=(τ / γ)⋅sin(δ)(τ=shear stress, γ=deformation, δ=phase angle=phase shift between shear stress and deformation vector).

[0151] A substance is generally considered to be pressure-sensitively adhesive and is defined as pressure-sensitively adhesive in the sense of the invention if, at room temperature, here defined as 23°C, in the deformation frequency range of 10 0 up to 10 1 rad / sec G' at least partly in the range of 10 3 up to 10 7 Pa and if G'' also lies at least partly in this range. “Partially” means that at least a section of the G' curve lies within the window defined by the deformation frequency range of 100 up to and including 10 1 rad / sec (abscissa) and the range of G' values from 10 3 up to and including 10 7 Pa (ordinate). This applies accordingly to G''.

[0152] Preferably, the pressure-sensitive adhesive has a deformation frequency range of 10 0 up to 10 1 rad / sec at 23 °C a storage modulus G' and a loss modulus G'' in the range of 10 3 up to 10 7 Pa, determined according to DIN EN ISO 6721.

[0153] To achieve viscoelastic properties, the monomers on which the polymers underlying the pressure-sensitive adhesive are based, as well as any other components present in the pressure-sensitive adhesive, are selected in particular such that the pressure-sensitive adhesive has a glass transition temperature (according to DIN 53765) below the application temperature (i.e., usually below room temperature (23 °C)). By using suitable cohesion-enhancing measures, such as crosslinking reactions (formation of bridge-forming links between the macromolecules), the temperature range in which a polymer mass exhibits pressure-sensitive adhesive properties can be increased and / or shifted. The application range of the pressure-sensitive adhesive can thus be optimized by adjusting the flowability and cohesion of the mass.

[0154] In particular, a pressure-sensitive adhesive has a glass transition temperature of ≤ 23 °C, determined according to DIN 53765.

[0155] For the sake of simplicity, the inventors define that a reactive pressure-sensitive adhesive tape within the meaning of the present invention preferably has an adhesive strength in the uncured state of at least 1 N / cm and that it can be removed almost residue-free (i.e., adhesive failure in the test). The adhesive strength is determined on steel analogously to ISO 29862:2007 (Method 3) at 23 °C and 50% relative humidity at a peel speed of 300 mm / min and a peel angle of 180°. An etched PET film with a thickness of 36 µm, such as that available from Coveme (Italy), is used as the reinforcing film. A 2 cm wide measuring strip is bonded using a 4 kg rolling machine at a temperature of 23 °C. The adhesive tape is peeled off immediately after application. The measured value (in N / cm) is the average of three individual measurements.Cohesive failure in this test is exhibited by adhesives or tapes that are tacky at room temperature and whose cohesion is insufficient for residue-free removal. Such adhesives or tapes are not considered pressure-sensitive adhesives within the meaning of the invention. Reactive adhesive tape system

[0156] The invention further provides a reactive adhesive tape system comprising at least a first reactive adhesive tape according to the invention comprising at least one reactively curable adhesive layer and a second reactive adhesive tape comprising at least one reactively curable adhesive layer, wherein the at least one reactively curable adhesive layer of the first reactive adhesive tape contains at least one initiator and preferably no redox catalyst and the at least one reactively curable adhesive layer of the second reactive adhesive tape contains at least one redox catalyst and preferably no initiator, wherein the second reactive adhesive tape is preferably also an adhesive tape according to the invention.

[0157] The initiator of the adhesive tape system according to the invention can be any of the initiators mentioned above, whereby all of the above statements apply.

[0158] Iron(II) phthalocyanine is preferably used as a redox catalyst.

[0159] In the adhesive tape system according to the invention, the reactive curing is triggered or activated by bringing the first reactive adhesive tape according to the invention into contact with the second reactive adhesive tape according to the invention.

[0160] It is understood that in all embodiments of the adhesive tape system according to the invention, the reactively curable adhesive layer of the first reactive adhesive tape does not contain a redox catalyst that triggers premature activation in the reactively curable adhesive layer of the first reactive adhesive tape.

[0161] Likewise, the reactively curable adhesive layer of the second reactive adhesive tape does not contain an initiator that is activated by the redox catalyst and triggers the activation prematurely.

[0162] A further object of the present invention is the production of the adhesive tape according to the invention.

[0163] The adhesive of the adhesive layer and, depending on the design, further adhesives are produced by known methods and brought into layer form, in particular by spreading.

[0164] Furthermore, one or more drying steps may be carried out if necessary.

[0165] The reactive adhesive tape according to the invention is produced, in particular, in the presence of a photoredox catalyst, while excluding UV light or visible light of the wavelength by which the respective initiator system or the respective photoredox catalyst is excited, in particular violet and blue light. These are generally wavelengths of less than 500 nm. Exclusion can generally be achieved with commercially available yellow light lamps or by covering normal light sources that have UV and / or violet and blue light components in their wavelength spectrum with commercially available UV-protective yellow light films.

[0166] The adhesive layer is produced in particular by the process steps described below: In a first step, the ingredients are dissolved or finely dispersed in one or more organic solvents and / or water. Suitable solvents are known in the art, with preference given to solvents in which at least one of the ingredients exhibits good solubility. Acetone and methyl ethyl ketone (MEK) are particularly preferred.

[0167] As used herein, the term ingredient comprises at least a) at least one polymer, b) at least one first radically polymerizable (meth)acrylate compound, c) at least one initiator, d) at least one redox catalyst and optionally further components, such as rheology-modifying fillers, as defined above or described as preferred.

[0168] In a second step, the dissolved or finely dispersed ingredients are then mixed using conventional mixing equipment. If necessary, the ingredients are dissolved, finely dispersed, and mixed simultaneously.

[0169] In a third step, a film, foil, layer, carrier, adhesive film, pressure-sensitive adhesive film, preferably a release liner or release paper, is coated with the mixture of dissolved, finely dispersed ingredients. The coating is carried out using conventional techniques known in the art.

[0170] After coating, the solvent is removed by evaporation in a fourth step. Depending on the solvent used, this preferably takes place in a temperature range of 60 °C to 80 °C.

[0171] For storage, the resulting layer or the reactive adhesive tape according to the invention is covered with a release liner or paper.

[0172] Another object of the present invention is a bonded composite comprising at least the following layers: • A first substrate A; and • A second substrate B; and • A reactive adhesive tape according to the invention or a reactive adhesive tape system according to the invention which is arranged between the substrate A and the substrate B and bonds the substrates A and B to one another.

[0173] A further object of the present invention is the production of a bonded composite using the adhesive tape according to the invention.

[0174] The process according to the invention for producing a bonded composite and thus for bonding two substrates, preferably at room temperature, using the reactive adhesive tape according to the invention comprises the following steps A) Applying the reactive adhesive tape to a first substrate B) Activation of the reactive adhesive tape by irradiation with UV light or blue light, wherein blue light in particular and for example has a wavelength of 460 nm, preferably by irradiation from a UV-LED lamp. C) Adding a second substrate to the reactive adhesive tape.

[0175] The adhesive tape according to the invention can be any of the described embodiments. In any case, the adhesive tape according to the invention comprises at least one reactively curable adhesive layer, which is activated in the process for producing a bonded composite according to step B).

[0176] The activation according to step B) can take place before step A) or after it.

[0177] Preferably, the activation according to step B) takes place before step C), in particular if activation through the first and second substrate is not possible.

[0178] In this process, particularly when carried out on an industrial scale, irradiation is preferably carried out with a wavelength of 365 nm or 385 nm, more preferably with 365 nm.

[0179] Irradiation can also preferably be carried out with a 460 nm LED radiation source. The results obtained by irradiation with 460 nm light are representative of irradiation with light with a wavelength of 365 nm or 385 nm.

[0180] In this case, too, the specialist will adapt the chronological sequence of the steps to the respective substrates and the nature and construction of the respective adhesive tape.

[0181] According to the invention, a method for producing a bonded composite and thus for bonding two substrates, preferably at room temperature, using the reactive adhesive tape system according to the invention also comprises the following steps: X1) Providing a first adhesive tape according to the invention which contains at least one initiator in the reactively curable adhesive layer; and X2) Providing a second adhesive tape according to the invention which contains at least one redox catalyst in the reactively curable adhesive layer; and X3) Providing a first substrate; and X4) providing a second substrate; and X5) Applying the first adhesive tape according to the invention to the first substrate; and X6) Applying the second adhesive tape according to the invention to the second substrate; and X7) Bringing the first adhesive tape according to the invention into contact with the second adhesive tape according to the invention.

[0182] Steps X1) to X7) can be carried out in any order, so that the two adhesive tapes can be brought into contact after application to the respective substrate or before.

[0183] In this case, too, the specialist will adapt the chronological sequence of the steps to the respective substrates and the nature and construction of the respective adhesive tapes.

[0184] The adhesive tape according to the invention is in particular a double-sided adhesive tape, and preferably a transfer adhesive tape.

[0185] Advantageously, the outer, exposed surfaces of the adhesive layers of the adhesive tape according to the invention can be provided with anti-adhesive materials such as a release paper or a release film, also called a liner. A liner can also be a material with an anti-adhesive coating on at least one side, preferably on both sides, such as a material siliconized on both sides. A liner, or more generally a temporary carrier, is not a component of an adhesive tape, but merely an aid for its production, storage and / or further processing by punching. Furthermore, in contrast to a permanent carrier, a liner is not firmly bonded to an adhesive layer, but rather functions as a temporary carrier, i.e. as a carrier that can be removed from the adhesive layer. In the present application, “permanent carriers” are synonymously also referred to simply as “carriers”.

[0186] The thickness of the individual adhesive layer(s) (in the z-direction) is preferably from 10 to 300 µm, particularly preferably from 15 to 150 µm, very particularly preferably from 20 to 100 µm, very particularly preferably from 25 to 70 µm.

[0187] A further object of the present invention is the use of the adhesive tape according to the invention or the adhesive tape system according to the invention for bonding components in electronic, optical or precision mechanical devices, automobiles, medical devices and dental devices.

[0188] Preference is given to using the reactive adhesive tape or adhesive tape system according to the invention for producing bonds on materials selected from plastic, metal, glass or ceramic and to using the reactive adhesive tape or adhesive tape system according to the invention as an adhesive in the manufacture of electronic, optical or precision mechanical devices.

[0189] Such portable devices include in particular: Photo cameras, digital cameras, photographic accessories (such as light meters, flash units, apertures, camera housings, lenses, etc.), film cameras, video cameras, small computers (mobile computers, pocket computers, calculators), laptops, notebooks, netbooks, ultrabooks, tablet computers, handhelds, electronic diaries and organizers (so-called “electronic organizers” or “personal digital assistants”, PDAs, palmtops), modems; Computer accessories and control units for electronic devices, such as mice, drawing pads, graphics tablets, microphones, speakers, game consoles, gamepads, remote controls, remote controls, touchpads; Monitors, displays, screens, touch-sensitive screens (sensor screens, “touchscreen devices”), projectors; Readers for electronic books (“e-books”); Small televisions, pocket televisions, film players, video players, radios (including small and pocket radios), walkmans, discmen, music players for CDs, DVDs, Blu-rays, cassettes, USB, MP3, headphones, cordless telephones, mobile phones, smartphones, two-way radios, hands-free devices, pagers, mobile defibrillators, blood glucose meters, blood pressure monitors, pedometers, heart rate monitors. flashlights, laser pointers; Mobile detectors, optical magnification devices, long-range vision devices, night vision devices, GPS devices, navigation devices, portable satellite communication interface devices; data storage devices (USB sticks, external hard drives, memory cards); and wristwatches, digital watches, pocket watches, chain watches, stopwatches.

[0190] Some examples are described below to further clarify the invention. Methods section - Test methods

[0191] Unless otherwise stated, all measurements are carried out at 23 °C and 50% relative humidity. Melting point T m

[0192] The melting point is determined on a hot plate. The substance is placed on a slide and observed with an optical microscope while the temperature is increased at a heating rate of 10 K / min. The melting point is the temperature at which the crystals begin to become liquid. Molecular weight M n , M w

[0193] The number average molecular weight M n or weight-average molecular weight M win this document refer to the determination by gel permeation chromatography (GPC). The determination is carried out on 100 µl of a clear-filtered sample (sample concentration 4 g / l). Tetrahydrofuran with 0.1 vol.% trifluoroacetic acid is used as the eluent. The measurement is carried out at 25 °C. A PSS-SDV column, 5 µm, 10 3 Å, 8.0 mm * 50 mm (information here and below in the order: type, particle size, porosity, inner diameter * length; 1 Å = 10 -10 m) is used. For separation, a combination of columns of type PSS-SDV, 5 µm, 10 3 Å and 10 5 Å and 10 6 Å, each with a diameter of 8.0 mm x 300 mm, were used (columns from Polymer Standards Service; detection using a Shodex RI71 differential refractometer). The flow rate was 1.0 ml per minute. Calibration was performed against PMMA standards (polymethyl methacrylate calibration) for polar molecules and against PS standards (polystyrene calibration) for all other molecules. thickness

[0194] The thickness of an adhesive layer can be determined by determining the thickness of a section of such an adhesive layer applied to a liner, defined in terms of its length and width, minus the (known or separately determinable) thickness of a section of the same dimensions of the liner used. The thickness of the adhesive layer can be determined using commercially available thickness gauges (touch-type testers) with an accuracy of less than 1 µm. If thickness fluctuations are detected, the average value of measurements taken at at least three representative locations is given, thus, in particular, excluding measurements at creases, folds, specks, and the like.

[0195] Just like the thickness of an adhesive layer, the thickness of an adhesive tape (adhesive strip) or a carrier can be determined analogously using commercially available thickness gauges (touch-type thickness gauges) with an accuracy of less than 1 µm. If thickness fluctuations are detected, the average value of measurements taken at at least three representative locations is given, thus excluding creases, folds, spots, and the like. Push-Out Steel (SUS-SUS) - initial (bonding strength)

[0196] The push-out test provides information about the bond strength of an adhesive product in the direction of the adhesive layer normal. A circular first substrate (1) (SUS, VA-1.4301 steel (mirror-polished on one side), thickness 3 mm) with a diameter of 21 mm, a square second substrate (2) (SUS, VA-1.4301 steel (mirror-polished on one side), thickness 2 mm) with a side length of 40 mm and a circular, centrally located opening (bore) with a diameter of 9 mm, and the adhesive tape sample to be tested, which was punched into a ring with an outer diameter of 18 mm and an inner diameter of 13 mm, creating a ring with a web width of 5 mm, are provided.

[0197] A test specimen is produced from the three components mentioned above by bonding the adhesive product with a free surface centered on the substrate (1). Then, the temporary protective film (siliconized PET liner) is removed and subjected to a minimum of 50 J / cm 2irradiated with a blue light LED (LED Spot 100 HP IC 460 nm from Hönle AG). Activation can also be achieved with a 365 nm UV LED (Hönle AG).

[0198] This bond is applied concentrically to the substrate (2) within 2 minutes with the now exposed side of the adhesive product, i.e. in such a way that the circular recess of the substrate (2) is positioned exactly centrally above the circular first substrate 1 (bonding area is thus 151 mm 2 ) and pressed with a pressure of at least 3 bar for at least 30 seconds, producing the test specimen.

[0199] After pressing, the test specimens are conditioned for 72 hours at 23 °C / 50 % relative humidity (RH). After storage, the adhesive bond is clamped into a specimen holder so that the bond is aligned horizontally. The test specimen is placed in the specimen holder with the disc (substrate (1)) facing down and the bond strength is measured in a device (Zwick). For this purpose, a steel punch with a diameter of 7 mm is moved through the circular opening in substrate (2) and the force required to separate the circular substrate (1) from the square substrate (2) is determined. The output value is the determined force divided by the bonded area and the force is given in MPa.

[0200] Three samples per product are tested and the mean value is given as an indicator for the bond strength. Push-Out Steel (SUS-SUS) - 4W@40°C

[0201] Furthermore, adhesive die-cuts of the examples according to the invention were stored for 4 weeks at a temperature of 40 °C, protected from light, before curing. Samples were then prepared, and the push-out was determined as a measure of the "bond strength after storage" and thus as a measure of the storage stability of die-cut adhesive products according to the above description. DSC

[0202] Differential scanning calorimetry (DSC) is performed on a Netzsch DSC 204 F1. The sample is weighed into reinforced aluminum crucibles (lids manually perforated). The temperature program runs two heating ramps: first, cooling from 25 °C to -100 °C with liquid nitrogen, followed by heating to 180 °C at 10 K / min. Table 1: Chemicals used 2-Phenoxyethyl acrylate (PEA) CAS No. 48145-04-6, monomer poly(meth)acrylate, BASF Methyl methacrylate (MMA) CAS No. 80-62-6, monomer poly(meth)acrylate, Sigma-Aldrich Vase ® 67 CAS No. 13472-08-7, 2,2'-Azobis(2-methylbutryronitrile), polymerization initiator, Akzo Nobel Di(4-tert-5-butylcyclohexyl) peroxydicarbonate CAS No. 15520-11-3, Polymerization Initiator, Akzo Nobel Levamelt ® 700 PE Ethylene-vinyl acetate copolymer, 70% vinyl acetate content, Arlanxeo Polyvinyl acetate CAS: 9003-20-7, Sigma-Aldrich Desmomelt ® 530 Largely linear, highly crystallizing polyurethane elastomer, Covestro MAPU 2-Methacryloxyethyl Phenyl Urethane, CAS: 51727-47-0, Cymer, M = 249.3 g / mol, solid at 21 °C, T m = 50 °C HECLA Hydroxyethyl caprolactone acrylate (oligomer), CAS: 110489-05-9, BASF ACMO 4-Acryloylmorpholine, CAS: 5117-12-4; M = 141 g / mol, liquid IPGA Isopropylidene Glycerol Acrylate, CAS: 13188-82-4, M = 186.2 g / mol, liquid NK ester CB1 β-Methacryloyloxyethyl hydrogen phthalate (Mono-2-(methacryloyloxy)ethyl phthalate) CAS: 27697-00-3, M = 278.3 g / mol, liquid, Kowa Visiomer DMAPMA N-[3-(Dimethylamino)propyl]methacrylamide, CAS: 5205-93-6, M = 170 g / mol, liquid, Evonik Ebecryl ® 8402 Aliphatisches Polyester Urethandiacrylat Oligomer, M w = 1770 g / mol, Allnex Peroxan ® IHP-50 50% by weight solution of diisopropyl hydroperoxide (CAS No.: 26762-93-6) in diisopropylbenzene, radical initiator, Pergan GmbH Ru(bpy)3 Cl2 / Tris(2,2'-bipyridyl) ruthenium(II) chloride as a hexahdyrat; Tris(2,2'-bipyridyl) ruthenium(II) chloride hexahydrate, Ru(bpy)3Cl2 · 6H2O; CAS No.: 50525-27-4, photoredox catalyst, Chemos GmbH Aerosil ® R202 CAS No.: 7631-86-9, hydrophobic fumed silica, Evonik AG Polymer P1 Polymethacrylate, manufactured as described Production of Polymer P1

[0203] A 4 L reactor conventional for radical polymerizations was charged with 320 g of a mixture of 69 wt% 2-phenoxyethyl acrylate and 31 wt% methyl methacrylate, as well as 273 g of ethyl acetate / isopropanol (96 / 04). After passing nitrogen gas through the reactor for 45 minutes with stirring, the reactor was heated to 58 °C, and 0.2 g of Vazo ®67 (2,2'-azobis(2-methylbutyronitrile)) was added. A further 480 g of the above-described monomer mixture and 377 g of ethyl acetate were added continuously over a period of 2 hours. The external heating bath was then heated to 65 °C, and the reaction was carried out at this constant external temperature. After 1 h and after 1.5 h of reaction time, 0.3 g and 0.3 g of 2,2'-azobis(2-methylbutyronitrile) were added, respectively. To reduce the residual monomers, 0.12 g of di(4-tert-5-butylcyclohexyl)peroxydicarbonate was added after 6 h and after 7.5 h. The mixture was diluted once with 160 g of ethyl acetate after 2 h and 4 h. The reaction was stopped after 24 h and cooled to room temperature. Preparation of the reactive adhesivesAqueous photoredox catalyst solution

[0204] Under yellow light, 5 g of tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate and 95 g of deionized 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 roller bench for 8 hours. Reactive adhesive

[0205] The base masses of the reactive adhesives were prepared in the laboratory according to the percentages listed in Table 2 below. The other raw materials were added to the prepared polymers in solvent, followed by the aqueous photoredox catalyst solution, which was then stirred. Commercial polymers used were prepared as a 40% solution in solvent. However, the amount of solvent is not specified in Table 2. Table 2 E1 E2 E3 E4 E5 E6 E7 E8 V1 V2 V3 V4 P1 56,37 54,97 - - - 32,87 61,07 39,97 54,97 54,97 54,97 54,97 Polyvinyl acetate - - - 59,97 - - - - - - - - Levamelt 700 - - 41,97 - - - - - - - - - Desmomelt530 - - - - 54,97 - - - - - - - MAPU - 15,5 21 14 24 - - 15,5 - - - - HECLA - 23,2 32 21 16 37,6 21,9 23,2 - - - - ACMO - - - - - - - - 38,7 - - - IPGA - - - - - - - - - 38,7 - - NK ester CB1 - - - - - - - - - - 38,7 - DMAPMA - - - - - - - - - - - 38,7 Ebecryl 8402 37,6 - - - - 23,5 11 15 - - - - Aerosil R 202 3,6 3,8 3,8 3,8 3,8 3,6 3,6 3,8 3,8 3,8 3,8 3,8 IHP-50 2,4 2,5 1,2 1,2 1,2 2,4 2,4 2,5 2,5 2,5 2,5 2,5 Ru-complex 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03 0,03

[0206] The adhesives were finally adjusted to a solids content of 34% with acetone. Production of reactive pressure-sensitive adhesive tapes

[0207] To produce the reactive adhesive layers, i.e., the carrier-free transfer pressure-sensitive adhesive tapes, the various reactive adhesives were applied from a solution to a conventional liner (siliconized polyester film) using a laboratory coating device and dried. The adhesive layer size was approximately 21 cm x 30 cm, and the adhesive layer thickness after drying was 100 ± 5 µm. Drying was carried out first at room temperature for 15 minutes and then for 15 minutes at 120 °C in a laboratory drying cabinet. Immediately after drying, the dried adhesive layers were laminated to the open side with a second liner (siliconized polyester film with lower release force).

[0208] Appropriate adhesive tapes were produced from the adhesives.

[0209] The bond strengths of the comparative adhesive tapes and the adhesive tapes according to the invention were determined according to the method given above, whereby activation is carried out by irradiation during sample preparation as stated in the method description for bond strength.

[0210] The results are summarized in Table 3 and supplemented as follows.

[0211] The inventive examples E1 to E8 and V1 show pressure-sensitive adhesives which, regardless of the polymeric film former used (polyacrylate, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyurethane), lead to high bond strengths of more than 3.5 MPa in the push-out test (initial) on steel.

[0212] According to the invention, E1, E6, and E7 contain a urethane-acrylate oligomer, while E2 to E5 contain the urethane-containing monomer MAPU. E8 contains both the oligomer and MAPU.

[0213] In examples E2 to E8, HECLA is also included as a second hydroxy-containing oligomer in combination with the first nitrogen-containing monomer.

[0214] In contrast to V1, E1 to E8 achieve values comparable to the fresh values even after storage at 40°C for 4 weeks. Monomers that carry a nitrogen-containing group according to the invention, such as N-vinylcaprolactam or the 4-acryloylmorpholine contained in V1, can be polymerized, but they lack storage stability, as they appear to evaporate over time, especially from narrow die-cuts.

[0215] V2 contains IPGA, a monomer without a nitrogen group. No curing occurs after irradiation. V3 also contains no monomer with at least one nitrogen-containing group, which is already evident from the very low push-out on steel. A DSC analysis was performed after curing. This adhesive tape showed a residual reactivity of almost 70% in the DSC, meaning it was obviously not fully reacted. If monomers bearing nitrogen-containing groups not contained in accordance with the invention are used, such as a tertiary amino group in V4, the shelf life is completely compromised, and the adhesive begins to cure during the drying step of production. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2014202402 A1

[0004] DE 10 2021 125429 A1

[0006] Cited non-patent literature

[0000] According to DIN EN 923: 2006-01

[0033] Steel analogous to ISO 29862:2007

[0155]

Claims

[1] Reactive adhesive tape comprising at least one reactively curable adhesive layer containing a) at least one polymer, and b) at least one first radically polymerizable (meth)acrylate compound, and c) at least one initiator and / or d) at least one redox catalyst, characterized by that the at least one first radically polymerizable (meth)acrylate compound is a monomer or oligomer having at least one nitrogen-containing group selected from amide, urethane and urea and the at least one first radically polymerizable (meth)acrylate compound has a melting point of greater than 45 °C and / or a molecular weight of more than 300 g / mol. [2] Reactive adhesive tape according to claim 1, characterized by that at least the monomer 2-methacryloxyethylphenylurethane (MAPU) is contained as the first radically polymerizable (meth)acrylate compound. [3] Reactive adhesive tape according to claim 1 or 2, characterized by that at least one (meth)acrylate-containing oligomer based on aliphatic polyurethanes, in particular based on polyester polyurethanes, is contained as the first radically polymerizable (meth)acrylate compound. [4] Reactive adhesive tape according to one of the preceding claims, characterized by that the reactively curable adhesive layer contains at least one second radically polymerizable (meth)acrylate compound which is a monomer or oligomer having at least one hydroxyl group. [5] Reactive adhesive tape according to claim 4, characterized by that as a second radically polymerizable (meth)acrylate compound at least one monomer or oligomer is included which is selected from the group consisting of hydroxyethylcaprolactone acrylate (HECLA), 2-hydroxy-3-phenoxypropyl acrylate (HPPA) and 2,3-dihydroxypropyl methacrylate. [6] Reactive adhesive tape according to one of the preceding claims, characterized by that the reactively curable adhesive layer contains at least the monomer 2-methacryloxyethylphenyl urethane (MAPU) as the first radically polymerizable (meth)acrylate compound and at least hydroxyethylcaprolactone acrylate (HECLA) as the second radically polymerizable (meth)acrylate compound. [7] Reactive adhesive tape according to one of the preceding claims, characterized bythat the polymer is selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), poly(meth)acrylates, polyurethanes (PU), polyvinyl acetates (PVA), polyvinyl alcohols, polyvinyl acetals, such as in particular polyvinyl butyral (PVB), polyesters and polymers of monomers comprising N-vinyl compounds, wherein the polymer is particularly preferably selected from the group consisting of ethylene-vinyl acetate copolymers (EVA), polyvinyl acetates (PVA), poly(meth)acrylates, poly(N-vinylcaprolactam), poly(N-vinylpyrrolidone) and polyurethanes (PU). [8] Reactive adhesive tape according to one of the preceding claims, characterized by that the first radically polymerizable (meth)acrylate compound has a melting point of at least 50 °C, particularly preferably of at least 55 °C, and / or a molecular weight of more than 400 g / mol, very particularly preferably of more than 500 g / mol. [9] Reactive adhesive tape according to one of claims 1 to 8, characterized bythat the at least one reactively curable adhesive layer is a light-curing adhesive layer and contains c) at least one initiator and d) at least one redox catalyst, wherein the redox catalyst is a photoredox catalyst. [10] Reactive adhesive tape according to claim 9, characterized by that the photoredox catalyst comprises ruthenium as the central atom and bipyridine or a mono- or polysubstituted bipyridine derivative as the ligand, or iridium as the central atom and phenylpyridine or a mono- or polysubstituted phenylpyridine derivative as the ligand. [11] Use of the adhesive tape according to one of claims 1 to 10 for bonding components in electronic, optical or precision mechanical devices, automobiles, medical devices and dental devices.