Reactive adhesive tape, reactive adhesive tape system, bonded assembly, and method for electro-debonding a bonded assembly

Abstract

The invention relates to a reactive adhesive tape, to a reactive adhesive tape system, to a bonded assembly, to a method for electro-debonding a bonded assembly, and to the use of the adhesive tape or adhesive tape system for bonding components in electronic, optical or precision mechanical devices, motor vehicles, medical devices and dental devices. The reactive adhesive tape comprises at least one layer of a reactive, cured adhesive compound D containing a base compound which contains a) one or more polymers, and b) one or more radically polymerizable monomers and / or oligomers, and c) at least one initiator, and / or d) at least one redox catalyst, and which reactive, cured adhesive compound D additionally contains e) at least one electrolyte.

Description

[0001] This invention relates to reactive tapes, reactive tape systems, bonded composites, methods for electrically debonding bonded composites, and uses of tapes or tape systems for bonding components in electronic devices, automobiles, medical devices, and dental devices.

[0002] Pressure-sensitive tapes based on the reactivity of monomers such as acrylates, especially room-temperature curing tapes, have been developed for many years and have reached a high level of maturity. An important issue remains the storage stability of the uncured tape. Storage should also be carried out at room temperature.

[0003] Reactive curable adhesive compositions and tapes produced therefrom are described in numerous existing technical documents. Here, reactive components (especially those based on acrylic monomers) are introduced into a polymer matrix film, particularly in the presence of substances that, upon activation, cause reactive curing of the adhesive composition but have not yet initiated any reaction in the storage state (i.e., unactivated). The reaction of the reactive component (e.g., polymerization or curing) can be initiated by external influences (e.g., by heat, moisture, plasma, radiation, etc.) or, for example, when two layers of the aforementioned type (one containing an initiator and the other containing an activator) are in direct contact with each other and the initiator is first activated by the activator. This allows for the acquisition of two-component adhesive systems in film form.

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

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

[0006] DE 10 2021 125429 A1 discloses, for example, adhesive films or pressure-sensitive tapes comprising a polymer and a film-forming polymer of at least one reactive acrylate monomer, an initiator, a photoredox catalyst, (d) N-vinyl compounds.

[0007] Due to environmental regulations, end-user awareness of sustainability, and increasing cost pressures during production, there is growing interest in "debonding-on-demand" functionality. Debonding processes are used in scenarios such as rework, repair, recycling, and processing aids.

[0008] Debonding techniques aim to achieve either cohesive cleavage of the adhesive layer or detachment of the adhesive layer from the substrate. While the former requires cleaning the substrate before re-bonding, the latter does not.

[0009] However, adhesive debonding techniques that ensure the required high and permanently reliable bond strength are generally quite difficult to achieve or take a very long time to implement, such as debonding using undermining solvents.

[0010] Therefore, especially in the rework or repair of electronic devices such as smartphones and tablets, the adhesives currently used are primarily cohesive decomposition adhesives, often in the form of pressure-sensitive tapes. Their cohesion decreases with increasing temperature to the point where manual cohesion separation of the bond can occur. This results in significant rework to prepare substrate surfaces contaminated with adhesive residues for re-bonding.

[0011] In addition to thermally mediated separation methods, electro-separation methods have also been discussed. For example, EP 3031875 B1 discloses reducing the adhesive strength of acrylate adhesive compositions by applying a voltage.

[0012] EP 3199344 B1 and DE 102005050632 A1 disclose the electro-debonding of compositions applied as hot melt adhesives.

[0013] EP 4067401 A1 discloses a liquid two-component adhesive system that can be electrochemically debonded after bonding has occurred.

[0014] EP4050040A1 discloses a liquid one-component adhesive that can be electrochemically debonded again by applying voltage for 30 minutes.

[0015] US 2007269659 A1 discloses a two-component adhesive that cures by bringing the two components into contact and then reducing the tensile strength of the bonded composite by applying a 50 V voltage.

[0016] However, adhesives produced by reactively curable tapes generally have very high bond strength.

[0017] Therefore, these tape solutions cannot be detached again, at least not without damaging the substrate to which they are bonded and without applying significant force. The fact that tapes that cure at room temperature, especially on sensitive, and particularly temperature-sensitive substrates, makes detachment even more difficult.

[0018] Therefore, the object of the present invention is to provide a reactive tape comprising at least one reactive curable adhesive composition layer D, wherein the tape should be able to be re-detached from at least one substrate with very little applied force. The substrate should not be significantly damaged, if any. This is especially possible in the case of temperature-sensitive substrates. At the same time, the adhesive strength of the tape to the substrate to be bonded should not be adversely affected before detachment. The reactive tape should also exhibit good storage stability. This applies not only to tapes in the form of rolls. Conversely, smaller die-cut pieces or elongated die-cut pieces with high surface areas should also exhibit good storage stability.

[0019] According to the present invention, this objective is achieved by the reactive adhesive tape according to claim 1.

[0020] The terms "reactive curable tape" and "reactive tape" are used synonymously in the context of this invention. This similarly applies to adhesive compositions and adhesive composition layers.

[0021] The reactive tape according to the invention comprises at least one reactive curable adhesive composition layer D containing a base composition, wherein the base composition comprises: a) One or more polymers, and b) One or more monomers and / or oligomers capable of free radical polymerization, and c) At least one initiator, and / or d) At least one redox catalyst, Furthermore, the adhesive composition layer D capable of reacting and curing further comprises: e) At least one electrolyte.

[0022] The presence of electrolytes allows the adhesive composition layer D to be electrically debonded by applying voltage.

[0023] Surprisingly, it has been found that, after curing and bonding to a substrate, the reactive tape according to the invention can be easily and quickly debonded from the bonded substrate electrically again without applying a large force by applying voltage, while the high adhesive strength of the tape to the substrate is not adversely affected before debonding.

[0024] Tapes and methods for electro-debonding or for reducing the adhesive strength of electro-adhesives are known in principle in the prior art. Therefore, as described above, EP 3031875 B1 discloses such an electrical process. The adhesive composition capable of electro-debonding is an acrylate-based adhesive composition.

[0025] As described above, hot melt adhesives and liquid 1- and 2-component systems can also be formulated to be electrically debonded.

[0026] However, unforeseen in the case of this invention, even reactive film-form tapes, which exhibit relatively high adhesive strength to various substrates, can be electrically debonded after bonding, compared to non-reactive pressure-sensitive tapes, especially since the adhesive strength of the tape to be bonded to the substrate is not adversely affected before debonding. Furthermore, debonding is clean and simple.

[0027] In particular, it is unforeseen that the relatively rigid matrix in the adhesive film or tape can be designed to be electrically debonded, the electrolyte even compatible with the matrix containing residues of reactive chemicals, and the electrolyte can migrate through the matrix quickly enough without adversely affecting the bond strength.

[0028] Surprisingly, it has also been found that even relatively small die-cut parts, as well as die-cut parts with a slender, fine structure (material width less than 1 cm) and therefore a relatively high surface area combined with a small adhesive surface area, can achieve sufficient storage stability and high adhesive force and / or bond strength before debonding.

[0029] The tape according to the invention is particularly suitable for miniaturized applications, such as those required in the electronics industry. More importantly, it enables the connection between components in a very precise and space-saving manner.

[0030] The reactive tape according to the invention is preferably a double-sided tape. For simplicity, in the context of the invention, in the case of a double-sided embodiment, the tape according to the invention is also referred to as "tape".

[0031] This invention relates to adhesive tapes that can be in any desired form, with tape rolls being preferred. Adhesive tapes, especially those in web form, can be produced in rolls (i.e., wound onto themselves in the form of an Archimedean spiral) or as strips, for example, in the form of pre-cut or die-cut pieces.

[0032] The tape according to the invention is, in particular, in the form of a web before pre-cutting or die-cutting. A web is understood to mean an object whose length (range in the x-direction) is many times greater than its width (range in the y-direction) and whose width is approximately and preferably precisely uniform along its entire length.

[0033] In the context of this invention, the general term “tape” (also synonymously referred to as “tape strip”) encompasses all sheet-like structures, such as films or film portions extending in two dimensions, strips having an extended length and a finite width, strip portions, etc., and finally, die-cut pieces or labels.

[0034] In addition to its longitudinal (x-direction) and transverse (y-direction) extents, the tape also has a thickness (z-direction) extending perpendicular to both extents, where the transverse and longitudinal extents are many times larger than the thickness. Ideally, the thickness is uniform across the entire surface of the tape, determined by its length and width, and preferably precisely uniform within tolerances.

[0035] The foregoing applies similarly to one or more carrier layers, and in some preferred embodiments, the carrier layer forms layers in the x- and y- directions as a constituent of the tape.

[0036] It goes without saying that each layer is arranged on top of the others along the z-direction.

[0037] All contents in this specification apply to the reactive tapes according to the invention, the reactive tape system according to the invention, the method for producing tapes according to the invention, the method for producing tape systems according to the invention, the bonded composites according to the invention, the method for producing bonded composites according to the invention, and the method for electrically debonding the composites, as well as the use of the tapes or tape systems according to the invention.

[0038] This invention also covers all features that are part of the subject matter of any dependent claim. Furthermore, this invention covers various features and combinations thereof that may have different levels of preference. Thus, this invention covers, for example, combinations of a first feature referred to as "preferred" and a second feature referred to as "particularly preferred." The subject matter described herein in the context of "implementation" is also covered, which may similarly have different levels of preference.

[0039] The adhesive composition of layer D, which is capable of reacting and curing, is described in more detail below.

[0040] The adhesive composition layer D contains at least one electrolyte.

[0041] In this case, “electrolyte” is understood to mean a chemical compound that “dissociates into ions in a solid, liquid or dissolved state and moves in a directional manner under the influence of an electric field”, see the Wikipedia entry “Electrolyt” dated April 1, 2023.

[0042] The electrolyte for the adhesive composition layer D is preferably selected from ionic liquids and metal salts, with ionic liquids being particularly preferred.

[0043] In particular, when using one or more ionic liquids as electrolytes, the tape can be easily debonded without adversely affecting its adhesive properties. Ionic liquids have the advantages that they can be easily and uniformly distributed in the polymer matrix of the adhesive composition, and that debonding occurs more quickly compared to other electrolytes.

[0044] Furthermore, the components of ionic liquids are not volatile, especially at room temperature. In addition, ionic liquids are relatively thermally stable and non-flammable, and are also relatively chemically stable.

[0045] In the context of this invention, an ionic liquid is a salt that is liquid at room temperature, i.e., 23°C. Ionic liquids accordingly contain both anions and cations.

[0046] Therefore, in the context of the separation method / method for electro-deadlocking according to the present invention, ionic liquids are particularly suitable as electrolytes.

[0047] When a voltage is applied, anions migrate to the anode side and cations migrate to the cathode side. Not wishing to limit ourselves to this, it can be hypothesized, in terms of mechanism, that this results in a decrease in the adhesive force / bonding strength of the adhesive composition layer containing the ionic liquid to at least one substrate, thereby causing adhesive cracking between the adhesive composition and the at least one substrate.

[0048] All ionic liquids are suitable in principle within the context of this invention.

[0049] The ionic liquid used in the context of this invention contains at least one anion and at least one cation. It is also conceivable that the ionic liquid contains two or more types of anions and / or two or more types of cations. Furthermore, it is conceivable to add two or more different ionic liquids to the adhesive composition layer D, thus making the adhesive composition layer D contain two or more different ionic liquids.

[0050] The anions in ionic liquids are preferably selected from: Br - AlCl4 - Al2Cl7 - NO3 - BF4 - PF6 - CH3COO - CF3COO - CF3CO3 - CF3SO3 - (CF3SO2)2N - (CF3SO2)3C - AsF6 - SbF6 - CF3(CF2)3SO3 - (CF3CF2SO2)2N - CF3CF2CF2COO - (FSO2)2N - N(CN)2 -Benzoate, octanoate, 2-hydroxypropane-1,2,3-tricarboxylate, methylphosphonate, ethyl sulfate.

[0051] Therefore, surprisingly, an extremely high reduction in adhesive strength is achieved by applying voltage to a reactive, curable adhesive composition, and thus, exceptionally good electro-detack properties are achieved in the tape according to the invention. Detack using this anionic method proceeds particularly quickly, leaving no residue.

[0052] The anions in ionic liquids are preferably selected from: Br - AlCl4 - Al2Cl7 - NO3 - BF4 - PF6 - CH3COO - CF3COO - CF3CO3 - CF3SO3 - (CF3SO2)2N - (CF3SO2)3C - AsF6 - SbF6 - CF3(CF2)3SO3 - (CF3CF2SO2)2N - CF3CF2CF2COO - (FSO2)2N - N(CN)2 - .

[0053] The anion is particularly preferably selected from (CF3SO2)2N - (FSO2)2N - PF6 - and N(CN)2 - .

[0054] These anions are particularly suitable because they achieve optimal electro-deadhesion. Deadhesion with these anions proceeds especially quickly and leaves no residue.

[0055] (FSO2)2N - PF6 - and N(CN)2 - It is a very preferred choice, and (FSO2)2N - It is the best option.

[0056] The cation of the ionic liquid is preferably selected from imidazolium-based cations, pyridinium-based cations, pyrrolidine-based cations, ammonium-based cations, phosphonium-based cations, oxazolium-based cations, guadinium-based cations, and thiazolium-based cations.

[0057] The cation of the ionic liquid is particularly preferably selected from imidazolium-based cations, pyridinium-based cations and ammonium-based cations, with imidazolium-based cations and pyridinium-based cations being even more preferred.

[0058] Therefore, surprisingly, an extremely high reduction in adhesive strength is achieved by applying voltage to a reactive, curable adhesive composition, and thus, exceptionally good electro-detack properties are achieved in the tape according to the invention. Detack using this anionic method proceeds particularly quickly, leaving no residue.

[0059] Furthermore, it is particularly preferred to use cations based on imidazolium.

[0060] These cations are particularly suitable because they achieve optimal electro-deadhesion. Deadhesion with these cations proceeds especially rapidly and leaves no residue.

[0061] The cation is particularly preferably selected from 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium. The cation is even more preferably...

[0062] 1-Butyl-3-methylimidazolium.

[0063] Therefore, surprisingly, an extremely high reduction in adhesive strength is achieved by applying voltage to a reactive, curable adhesive composition, and thus, exceptionally good electro-detack properties are achieved in the tape according to the invention. Detack using this anionic method proceeds particularly quickly, leaving no residue.

[0064] The electrolyte in adhesive composition layer D is preferably selected from ionic liquids: 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIM-TFSI) 1-Butyl-3-methylimidazolium bis(fluorosulfonyl)imide (BMIM-FSI) 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI) 1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-FSI), 1-Ethyl-3-methylimidazolium dicyandiamide, 1-Butyl-3-methylimidazolium hexafluorophosphate, 1-Hexyl-3-methylimidazolium hexafluorophosphate, 1-Methyl-3-octylimidazolium hexafluorophosphate, 1-butylpyridinium hexafluorophosphate, 1-Butyl-3-methylpyridinium hexafluorophosphate, 1-Butyl-4-methylpyridinium hexafluorophosphate, 1-Ethyl-3-methylimidazolium hexafluorophosphate, 1-Ethyl-2,3-dimethylimidazolium hexafluorophosphate, 1-Butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-Methyl-3-propylimidazolium hexafluorophosphate, 1-Methyl-3-pentylimidazolium hexafluorophosphate, 1-heptyl-3-methylimidazolium hexafluorophosphate, 1-dodecyl-3-methylimidazolium hexafluorophosphate, 1-Methyl-3-tetradecylimidazolium hexafluorophosphate, 1-methyl-3-nonylimidazolium hexafluorophosphate, 1-hexadecyl-3-methylimidazolium hexafluorophosphate, 1-Decyl-3-methylimidazolium hexafluorophosphate, 1-methyl-3-octadecylimidazolium hexafluorophosphate, 1-benzyl-3-methylimidazolium hexafluorophosphate, 1,3-Diethylimidazolium hexafluorophosphate, 1-Ethyl-3-propylimidazolium hexafluorophosphate, 1-Butyl-3-ethylimidazolium hexafluorophosphate, 1-Butyl-1-methylpiperidinium hexafluorophosphate, 1-methyl-1-propylpiperidinium hexafluorophosphate, 1-Ethylpyridinium hexafluorophosphate, 1-Butyl-3-methylpyridinium hexafluorophosphate, 1-Propylpyridinium hexafluorophosphate, 1-Butyl-4-methylpyridinium hexafluorophosphate, 1-Butylpyridinium hexafluorophosphate, 1-Hexylpyridinium hexafluorophosphate, 1-Butyl-2-methylpyridinium hexafluorophosphate, 1-ethyl-1-methylpyrrolidinium hexafluorophosphate, 1-methyl-1-propylpyrrolidinium hexafluorophosphate, Trihexyltetradecylphosphonium hexafluorophosphate.

[0065] The electrolyte in adhesive composition layer D is particularly preferably selected from ionic liquids: 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIM-TFSI) 1-Butyl-3-methylimidazolium bis(fluorosulfonyl)imide (BMIM-FSI) 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI) 1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-FSI) and 1-Ethyl-3-methylimidazolium dicyandiamide.

[0066] The adhesive composition layer D preferably comprises 0.5 to 25 parts by weight, particularly preferably 2 to 22 parts by weight, of an electrolyte, preferably an ionic liquid, based on 100% by weight of the base composition.

[0067] Such a preferred or particularly preferred amount of electrolyte, especially ionic liquid, enables relatively rapid electro-debonding, while the adhesion of the adhesive composition layer to adjacent layers, especially at least one substrate, is not adversely affected before debonding.

[0068] Surprisingly, adhesive composition layers D containing up to 22 parts by weight of an ionic liquid can also be prepared. Some of these exhibit significantly improved adhesive strength compared to adhesive composition layers without an electrolyte, and they readily detach after the application of a suitable voltage.

[0069] In a preferred embodiment of the invention, the adhesive composition layer D contains 5 to 25 parts by weight, particularly preferably 13 to 22 parts by weight, of an electrolyte, preferably an ionic liquid.

[0070] Depending on the flexibility of layer D of the adhesive composition containing ionic liquid, appropriate corrective additives, especially rheology modifiers, can be used.

[0071] In another preferred embodiment of the invention, the adhesive composition layer D contains 0.5 to 18 parts by weight, particularly preferably 2 to 12 parts by weight, of an electrolyte, preferably an ionic liquid.

[0072] The composition of adhesive composition layer D is a reactive adhesive composition.

[0073] In the context of this invention, "reactive curable adhesive composition" is understood to mean an adhesive composition that cures through a chemical reaction of at least one corresponding reactive component to produce an adhesive bond.

[0074] In the context of this invention, such adhesive compositions are also referred to as "reactive adhesive compositions".

[0075] The reactive curable tapes and corresponding reactive adhesive compositions according to the invention are preferably used as structural adhesives or semi-structural adhesives after curing. According to DIN EN 923: 2006-01, structural adhesives are adhesives that form adhesive bonds and can maintain specified strength in a microstructure over a predetermined extended period of time (according to ASTM definition: "adhesives for transferring desired loads between adherends exposed to the typical service environment of the structure involved"). Therefore, they are adhesives for bonding that can withstand high chemical and physical stresses and contribute to the consolidation of the tape in the cured state.

[0076] The term "(semi-)structural adhesive" encompasses both "semi-structural adhesive" and "structural adhesive". "Semi-structural adhesive" is a cured adhesive having a tensile shear strength of at least 1.0 MPa, more preferably at least about 1.5 MPa, in each case on steel, in a tensile shear test. "Structural adhesive" is a cured adhesive having particularly high tensile shear strength and having a tensile shear strength of at least 5 MPa, more preferably at least 7 MPa, and even more preferably at least 10 MPa, in each case on steel, in a tensile shear test.

[0077] As described above, the chemical reaction occurs after activation, for example by heat, moisture, plasma, radiation, or by bringing two adhesive composition layers containing suitable reactants into contact.

[0078] In the context of this invention, a reactive curable tape is preferred, wherein curing is achieved by using radiation activation, particularly by using light with wavelengths in the visible range of the electromagnetic spectrum or by using UV light, or by contact with another reactive curable adhesive composition layer or a corresponding reactive curable tape.

[0079] The base composition of the adhesive composition layer D that can react and cure contains at least: a) One or more polymers, and b) One or more monomers and / or oligomers capable of free radical polymerization, and c) At least one initiator, and / or d) At least one redox catalyst.

[0080] The total mass of the components of the base composition is 100% by weight (wt%), wherein the electrolyte (e) is not part of the base composition.

[0081] The reported amounts of components a) through d) by weight percentage are based on the total weight of the base composition in each case.

[0082] As described below, the amount of any additives present is also included in 100% by weight of the base composition.

[0083] The base composition is formed, in particular, from all the components of an adhesive composition that is reactive and curable, unlike the electrolyte (e).

[0084] Any other optional components, such as solvents or water, are only helpful for production and are not included in the total weight of the components of the base composition. This also applies to solvents that may already be present in commercially available raw materials.

[0085] The reactive curable adhesive composition layer D preferably contains 80% or more of the base composition, based on the total mass of the reactive curable adhesive composition layer D.

[0086] In a preferred embodiment of the invention, the reactive curable adhesive composition layer D consists of a base composition and an electrolyte added in e).

[0087] a) Polymer

[0088] A single polymer or multiple polymers may exist. Therefore, the description of "polymer" by its definition and the expression "total" encompass 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 to the chemical properties of the corresponding compound, rather than to its amount of substance in the manner customary in the art.

[0089] The base composition preferably contains 10% to 60% by weight of at least one polymer a), more preferably 25% to 60% by weight and especially preferably 50% to 70% by weight of at least one polymer a), in each case based on the total mass of the base composition.

[0090] Weight percentage (%) is based on one polymer or the sum of all polymers (if two or more polymers are present).

[0091] In a preferred embodiment of the invention, the polymer is selected from ethylene-vinyl acetate copolymer (EVA), poly(meth)acrylates, polyurethane (PU), polyvinyl acetate (PVA), polyvinyl acetal such as, in particular, polyvinyl butyral (PVB), polyesters, and polymers containing monomers comprising N-vinyl compounds.

[0092] Particularly preferred, the polymer is selected from ethylene-vinyl acetate copolymer (EVA), poly(meth)acrylate, poly(N-vinylcaprolactam), poly(N-vinylpyrrolidone), and polyurethane (PU).

[0093] In a particularly preferred embodiment, the base composition contains at least one poly(meth)acrylate. The base composition preferably contains 10% to 60% by weight, particularly preferably 25% to 60% by weight, and especially preferably 50% to 60% by weight of poly(meth)acrylate.

[0094] "Poly(meth)acrylate" is understood to mean a polymer that can be obtained by polymerization (e.g., free radical polymerization) of acrylic and / or methacrylic monomers and optionally other copolymerizable monomers. "Poly(meth)acrylate" is particularly understood to mean a polymer whose monomer base consists of acrylic acid, methacrylic acid, acrylates and / or methacrylates in a monomeric basis of at least 50% by weight, preferably at least 30% by weight, wherein the acrylates and / or methacrylates are present at least proportionally, based on the total monomer base of the polymer.

[0095] The base composition preferably contains at least one poly(meth)acrylate, i.e., it may contain one or more poly(meth)acrylates. The terms "at least one," "one or more," or "exactly one" refer to the chemical properties of the corresponding compound, rather than to its amount of substance in the manner customary in the art. This also applies to the monomer composition of the poly(meth)acrylate.

[0096] For example, a monomer composition may contain only n-butyl acrylate as a monomer, which would mean that the monomer composition contains multiple n-butyl acrylate molecules.

[0097] In principle, poly(meth)acrylates can be any desired poly(meth)acrylate.

[0098] In a preferred embodiment of the invention, the poly(meth)acrylate present can be produced by polymerization of a monomer composition containing one or more monomers selected from: ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-heptyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, Isooctyl 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, isoborneol acrylate, norborneol acrylate, benzyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, cyclohexyl acrylate, 1-acryloyloxy-3-hydroxyadamantane, 4-[(6-Acryloyloxy)hexyloxy]-4'-cyanobiphenyl, N-succinimide acrylate, 1-Ethylcyclopentyl acrylate, N-tert-octylacrylamide, N-tert-butylacrylamide, dimethylacrylamide, diethylacrylamide, N-isopropylacrylamide, N-hydroxyethylacrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-[3-(dimethylamino)propyl]acrylamide, diacetone acrylamide, N-(butoxymethyl)acrylamide, N-phenylacrylamide, N-[2-(dimethylamino)ethyl]acrylamide, N-[2-(diethylamino)ethyl]acrylamide, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glyceryl formal methacrylate, 2-dimethylaminoethyl methacrylate, phenoxyethyl methacrylate, 9-anthrayl methyl methacrylate 2-Ethyl-2-adamantyl methacrylate, 2-(acetylacetoxy)ethyl methacrylate, 2-isopropyl-2-methacryloyloxyadamantane, isopropyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, furfuryl methacrylate, 2-methacryloyloxy-2-methyladamantane 2-morpholino ethyl methacrylate, phenyl methacrylate, N-succinimide methacrylate, 2-(tert-butylamino)ethyl methacrylate, 2-cyclohexylpropyl-2-yl methacrylate 1-Adamantyl methacrylate, 1-Methylcyclopentyl methacrylate N-tert-butylmethacrylamide, N-(methoxymethyl)methacrylamide, N,N-dimethylmethacrylamide, methacrylamide, N-phenylmethacrylamide, N,N-dimethylmethacrylamide, N-isopropylmethacrylamide, N-vinylformamide, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylcarbazole, N-vinylimidazolium, vinylmethyloxazolidinone, N-vinyl-N-methylacetamide, hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 4-hydroxyethylacrylamide, acrylic acid, methacrylic acid, 2-acryloyloxyethyl succinate, methacryloyloxyethyl succinate, ethyl sulfomethacrylate, methacrylamide, glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl methyl acrylate, 3,4-Epoxycyclohexyl methyl methacrylate, 4-Hydroxybutyl acrylate glycidyl ether 4-Hydroxybutyl methacrylate glycidyl ether, isocyanato ethyl acrylate, isocyanato ethyl methacrylate, 2-[2-(methacryloyloxy)ethoxy]ethyl isocyanate, 2-[2-(acryloyloxy)ethoxy]ethyl isocyanate and α,α-dimethyl-m-isopropenyl benzyl isocyanate.

[0099] In a preferred embodiment, the poly(meth)acrylate present can be produced by polymerization of a monomer composition containing the following monomers: 2-Phenoxyethyl acrylate (PEA) and methyl methacrylate (MMA).

[0100] In another particularly preferred embodiment, the base composition contains at least one polyurethane. The base composition preferably contains 10% to 60% by weight, particularly preferably 25% to 60% by weight, and especially preferably 30% to 50% by weight of polyurethane.

[0101] Thermoplastic polyurethanes having a crystallization melt 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 is the temperature at which the thermoplastic granules adhere to themselves. When the polymer is a semi-crystalline thermoplastic polymer, it very preferably has a glass transition temperature of no more than 25°C, and preferably no more than 0°C, in addition to its softening temperature (which relates to the melting of microcrystals).

[0102] In a preferred embodiment, at least one thermoplastic polyurethane is used. Commercially available thermoplastic polyurethanes include, for example, Desmocoll from Covestro AG (Leverkusen, Germany). ® 530 / 1 and Desmocoll ® 540 / 3 and Desmomelt ® 530, or IROSTIC from Huntsman (Huntsman Holland BV, Botlek-Rotterdam, Netherlands) ® S-6558-06 and IROSTIC ® S 8612, or alternative variants from these product lines. Elastollan from BASF (Ludwigshafen, Germany) also exists. ® The product line may also be Pearlbond from Lubrizol (Lubrizol Advanced Materials Europe BVBA, Brussels, Belgium).

[0103] Thermoplastic polyurethanes preferably have a softening temperature of less than 100°C, especially less than 80°C. Preferred examples of such thermoplastic polyurethanes include Desmomelt. ® 530 and IROSTIC ® S-6558-06. Desmomelt ® 530 is a hydroxyl-terminated, mostly linear, thermoplastic, highly crystalline polyurethane elastomer. According to the manufacturer, IROSTIC ® S-6558-06 is a linear thermoplastic polyurethane for use in solvent-based adhesives. According to the manufacturer, it features a very low crystallization rate, a long open assembly time, and a very low activation temperature.

[0104] In another particularly preferred embodiment, the base composition comprises at least one polymer consisting of a monomer comprising an N-vinyl compound.

[0105] The base composition preferably contains 5% to 50% by weight, particularly preferably 5% to 30% by weight, and especially preferably 10% to 20% by weight of a polymer containing a monomer comprising an N-vinyl compound.

[0106] Examples of such N-vinyl compounds include N-vinylacetamide (CAS No. 5202-78-8), N-vinylcaprolactam (CAS No. 2235-00-9), N-vinylpyrrolidone (CAS No. 88-12-0), N-vinyl-N-methylacetamide (CAS No. 3195-78-6), 5-methyl-3-vinyl-2-oxazolidinone (CAS No. 3395-98-0), or N-vinylisobutyramide.

[0107] Preferred compounds are N-vinyl lactams and N-vinyl oxazolidinones. N-vinyl caprolactam (CAS No. 2235-00-9), N-vinyl pyrrolidone (CAS No. 88-12-0), or 5-methyl-3-vinyl-2-oxazolidinone (CAS No. 3395-98-0) of the polymer are preferred.

[0108] N-vinylcaprolactam and / or N-vinylpyrrolidone are preferred, and the N-vinyl compound N-vinylcaprolactam (NVC) of the polymer is even more preferred.

[0109] In a preferred embodiment of the invention, at least the polymer poly-N-vinylcaprolactam is thus present as a polymer in the base composition of the adhesive composition layer D.

[0110] This surprisingly promoted curing.

[0111] In a preferred embodiment of the invention, the polymer of the reactive adhesive composition in the reactive tape according to the invention, especially, for example, poly(meth)acrylate, is substantially inert to at least one free radical polymerizable monomer or oligomer and initiator system, as well as any other substances present. In this context, the term "inert" is understood to mean that the free radical polymerizable monomer or oligomer and initiator system, as well as any other substances present, do not substantially react with the polymer, especially poly(meth)acrylate, under suitably selected conditions, particularly at room temperature (23°C), prior to photocuring.

[0112] Therefore, in a preferred embodiment, the monomer composition of the polymer / poly(meth)acrylate is free of acids, especially acrylic acid or other monomers having one or more carboxyl groups, and is free of amines, especially tertiary amines, as comonomers.

[0113] In certain embodiments, one or more poly(meth)acrylates are inert even after activation by the curing reaction. This is understood to mean that the poly(meth)acrylate is not a co-reactant in the free radical reaction.

[0114] b) Monomers and / or oligomers capable of free radical polymerization

[0115] The base composition of the reactive adhesive composition of the reactive tape according to the present invention comprises at least one monomer or oligomer b) capable of free radical polymerization.

[0116] As understood by those skilled in the art, monomers or oligomers capable of free radical polymerization are understood to mean monomers or oligomers capable of free radical chain polymerization.

[0117] Oligomers capable of free radical polymerization, especially as opposed to polymers, are particularly understood by those skilled in the art to mean a weight-average molecular weight distribution M of less than 35,000 g / mol, especially less than 15,000 g / mol, especially less than 10,000 g / mol. w Compounds capable of free radical polymerization, and in the context of this invention, particularly those having a weight-average molecular weight distribution M of less than 35,000 g / mol, especially less than 15,000 g / mol, especially less than 10,000 g / mol. w Acrylate- or methacrylate-esterified ether oligomers, butadiene oligomers, ester oligomers, carbonate oligomers, organosilicon oligomers, and epoxy compounds. These include, in particular, epoxy (meth)acrylates, aliphatic, aromatic, and organosilicon-urethane (meth)acrylates, aliphatic and aromatic polyester (meth)acrylates, polybutadiene (meth)acrylates, dendritic (meth)acrylates, polyether (meth)acrylates, and polycarbonate (meth)acrylates, for example, those available from Miwon and Bomar, such as MIRAMER SC2565 from Miwon with a Mw of 5200 g / mol, or oligomers based on aliphatic polyurethanes, especially polyester polyurethanes, such as aliphatic urethane diacrylates available under the trade names EBECRYL® 8402, EBECRYL® 4858, or EBECRYL® 8809, or acrylated oligomers based on caprolactone, such as commercially available hydroxyethylcaprolactone acrylate (HECLA; CAS No. 110489-05-9). The functionality of the polymerizable oligomer, i.e., the number of radically polymerizable groups per molecule, is preferably 1 to 20, typically 2 to 15, and primarily 2 to 6. The dynamic viscosity, measured at 25°C according to DIN 53019-1, 2008, is preferably greater than 1 Pas, but particularly preferably significantly greater than 10 Pas. This is particularly suitable for producing good pressure-sensitive adhesive compositions with sufficient cohesion to use oligomers with a dynamic viscosity of greater than 20 Pas, preferably greater than 30 Pas, at 25°C as components of the adhesive composition. In the context of this invention, dynamic viscosity is defined as the viscosity measured at 25°C according to DIN 53019-1, 2008 as 1 s⁻¹. -1 The shear rate was determined.

[0118] In a preferred embodiment, the reactive tape according to the invention is characterized in that at least one free-radical polymerizable monomer or oligomer has a boiling point of at least 30°C, preferably at least 60°C, and particularly preferably at least 80°C, at 1 mbar, or is in solid form at 23°C. Free-radical polymerizable oligomers are particularly preferred in this respect.

[0119] Therefore, in a preferred embodiment, the reactive tape according to the invention is characterized in that the base composition of the adhesive composition layer D comprises oligomers capable of free radical polymerization.

[0120] Suitable monomers capable of free radical polymerization are selected from acrylates (e.g., 2-hydroxy-3-phenoxypropyl acrylate), methacrylates, vinyl compounds and compounds having carbon-carbon double bonds, as well as crosslinkable monomers capable of free radical polymerization, such as diacrylates, dimethacrylates, triacrylates, trimethacrylates, and acrylates or methacrylates with higher functionality.

[0121] Suitable oligomers capable of free radical polymerization are especially oligomers having acrylate or methacrylate functional groups or vinyl functional groups, wherein the functionalization can be monofunctional or polyfunctional.

[0122] Particularly preferred are oligomers containing (meth)acrylates based on aliphatic polyurethanes, especially polyester-polyurethanes, such as aliphatic urethane diacrylates available under the trade name EBECRYL® 8402. Or acrylated low polyester, such as caprolactone-based, such as commercially available hydroxyethylcaprolactone acrylate (HECLA; CAS No. 110489-05-9).

[0123] For high adhesive strength, preferred monomers are acrylates and / or methacrylates in which the alcohol moiety of the ester contains a functional group. Preferred functional groups include aromatic groups, urethane groups, urea groups, oxygen or nitrogen heterocycles, ether groups, ester groups, or hydroxyl groups.

[0124] Examples of preferred monomers include 2-methacryloyloxyethyl phenylcarbamate (MAPU; CAS No. 51727-47-0) and 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-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-O-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-dioxolane-4-yl)methylprop-2-enoate (CAS No. 13188-82-4) Mono(2-acryloyloxyethyl) succinate (CAS No. 50940-49-3), Mono(2-methacryloyloxyethyl) succinate (CAS No. 20882-04-6) Ethyl methacrylate (2,2-pentamethylene-1,3-oxazolidyl-3) (CAS No. 4203-89-8) 2-Methyl-2-propylhexanoic acid 2-hydroxy-3-(prop-2-enoyloxy)propyl ester (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 crosslinked monomer diurethane dimethacrylate (mixture of isomers) (CAS No. 72869-86-4). Bisphenol A glyceryl ester dimethacrylate (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), trimethylolpropane propoxylate triacrylate (CAS No. 53879-54-2), trimethylolpropane triacrylate (CAS No. 15625-89-5), and / or bis(trimethylolpropane)tetraacrylate (CAS No. 94108-97-1). 2-hydroxy-3-phenoxypropyl acrylate, 2-[[(butylamino)carbonyl]oxy]ethyl acrylate, and dicarboxylate dimethacrylate are particularly preferred.

[0125] In a preferred embodiment, the monomers or oligomers present that are capable of free radical polymerization are acrylates and / or methacrylates having at least one hydroxyl group. For example, and particularly in a especially preferred embodiment, hydroxyethylcaprolactone acrylate (HECLA) is present.

[0126] This enables the creation of curable tapes that also exhibit high storage stability, meaning they do not undesirably undergo premature curing.

[0127] Considering good chemical stability, acrylates and / or methacrylates having phenyl and hydroxyl groups as functional groups are preferred, such as 2-hydroxy-3-phenoxypropyl acrylate (HPPA).

[0128] In another particularly preferred embodiment, the monomers or oligomers present that are capable of free radical polymerization are acrylates and / or methacrylates having nitrogen-containing functional groups, such as, in particular, urethane groups.

[0129] For example, and particularly in a especially preferred embodiment, 2-methacryloyloxyethyl phenylcarbamate (MAPU) is present. Such monomers appear to work particularly well in tapes, especially die-cut small parts. Without being bound by this particular theory, it is speculated that these monomers have a positive effect on the suppression of atmospheric oxygen.

[0130] In a preferred embodiment, the monomers and oligomers may also be used in combination with each other.

[0131] In a particularly preferred embodiment, the base composition comprises: 2-Methacryloxyethylphenylcarbamate (MAPU) and hydroxyethylcaprolactone acrylate (HECLA).

[0132] This enables the creation of curable tapes that also exhibit high storage stability, meaning they do not undesirably undergo premature curing. High adhesive strength is also achieved.

[0133] The base composition of the reactive adhesive composition of the reactive tape according to the invention preferably contains 10% to 80% by weight of at least one monomer or oligomer b) capable of free radical polymerization, more preferably 20% to 60% by weight and especially preferably 35% to 45% by weight of at least one monomer or oligomer b) capable of free radical polymerization, in each case based on the total weight of the components of the base composition of the reactive adhesive composition.

[0134] The weight percentages are based on monomers or oligomers capable of free radical polymerization or on the sum of all monomers and / or oligomers (if two or more monomers and / or oligomers are present). Solvents or water are used only to aid production and are generally not included in the total mixture of the components of the reactive tape or reactive adhesive composition or the base composition of the reactive adhesive composition according to the invention. This also applies to solvents that may already be present in commercially available raw materials.

[0135] In the reactive adhesive composition of the reactive tape according to the invention, the weight ratio of all polymers to all free radical polymerizable monomers or oligomers is preferably 3:1 to 1:3, more preferably 2:1 to 1:2, and especially 2:1 to 1:1.

[0136] c) Initiator and / or d) Redox catalyst

[0137] The base composition contains c) at least one initiator and / or d) at least one redox catalyst.

[0138] These listed components specifically represent initiator systems that initiate or activate reactions that enable the curing of reactive adhesive compositions.

[0139] Depending on the type of activation, different initiators and redox catalysts are suitable.

[0140] In the context of this invention, the term "initiator," especially "free radical initiator," or a substance that forms free radicals (or a curing agent), refers to a compound that can initiate the polymerization or crosslinking of an adhesive composition. However, initiators, especially free radical initiators, participate in the reaction to a very small extent and therefore do not form polymer fractions that determine the nature of the bonds.

[0141] In the context of this invention, the term "redox catalyst" is understood to mean a compound that can mediate electron transfer between chemical compounds that would otherwise react more slowly (if any).

[0142] In the context of this invention, the term "photoredox catalyst" is understood to mean a photosensitive or UV-sensitive compound that, when excited by light or UV light, mediates electron transfer between chemical compounds that would otherwise react more slowly (if any). In contrast to photoinitiators disclosed, for example, in EP 3910715 A1, photoredox catalysts do not decompose into reactive pyrolysis products upon irradiation with light or UV light, but only transform into an excited state, which is generally relatively persistent and from which redox processes can be initiated or mediated. Photoredox catalysts preferably do not initiate polymerization in mixtures containing monomers or oligomers capable of free radical polymerization at temperatures up to 90°C, even when the mixture is irradiated with UV or blue light. This applies to cases where no free radical initiator or other initiating substances are added to the mixture.

[0143] Therefore, the photo-redox catalyst is not an initiator or a free radical initiator. When irradiated with UV or blue light, it only activates the initiator, which then initiates polymerization. This delayed mechanism results in a so-called open assembly time, during which the tape can still be applied before reactive curing begins.

[0144] In the context of this invention, neither the redox catalyst nor the initiator is an initiator that can immediately initiate curing, for example, by light or heat activation.

[0145] In the context of this invention, the terms "redox catalyst" and "photoredox catalyst" are not intended to be limited to compounds that are not consumed together during the reaction.

[0146] In a preferred embodiment, the reactive tape according to the invention is characterized in that at least one reactive curable adhesive composition layer D is a photocurable adhesive composition layer, and contains c) at least one initiator and d) at least one redox catalyst, wherein the redox catalyst is a photoredox catalyst.

[0147] In a preferred embodiment, the reactive tape according to the invention is characterized in that the photoactivated initiator system, composed of an initiator and a photoredox catalyst, has an open assembly time of at least 1 minute, preferably at least 2 minutes, and particularly preferably at least 5 minutes. After activation and curing, the cured tape is no longer considered a "pressure-sensitive adhesive" tape.

[0148] The initiator is preferably a free radical initiator, although mixtures of two or more initiators are also conceivable. Any free radical initiator known in the art can be used. Preferred free radical initiators are peroxides, hydroperoxides, and azo compounds.

[0149] In a particularly preferred embodiment of the invention, the free radical initiator is an organic peroxide. Hydroperoxides are particularly preferred, especially diisopropylbenzene hydroperoxide (CAS No. 26762-93-6). Diisopropylbenzene hydroperoxide is preferably used in the form of a 50% solution of diisopropylbenzene, which is 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, for example. Additionally, 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.

[0150] The base composition preferably contains 0.1% to 9% by weight, particularly preferably 0.1% to 5% by weight and even more preferably 0.1% to 2% by weight of an initiator, preferably a free radical initiator, preferably selected from hydroperoxides.

[0151] The photoredox catalysts that can be used include those known to those skilled in the art. Photoredox catalysts are often transition metal complexes, depending on whether the ligands are in a neutral form or in the form of a cation having ruthenium, copper, or iridium as a central atom. The ligands that can be used for transition metal complexes preferably include bidentate ligands, especially those having at least two heteroaromatic six-membered rings bonded to each other, for example in the form of biphenyl, which may in turn be part of a more complex structure (e.g., polycyclic aromatic hydrocarbons and / or bridged bicyclic or polycyclic aromatic hydrocarbons). If a ligand containing a biphenyl structural unit is used, one of the aromatic rings of the biphenyl may advantageously form the "tooth" of the ligand, resulting in a bidentate nature. The bicyclic aromatic compound (e.g., biphenyl compound) or polycyclic aromatic compound as the ligand may be unsubstituted (i.e., with a hydrogen atom on each carbon atom) or may be monosubstituted or polysubstituted. In the context of this invention, transition metal complexes are used as photoredox catalysts.

[0152] In a preferred embodiment of the present invention, the photo-oxidation-reduction catalyst is a transition metal complex having ruthenium as a central atom and bipyridine or mono- or poly-substituted bipyridine derivatives as ligands.

[0153] In another preferred embodiment of the present invention, the photo-oxidation-reduction catalyst is a transition metal complex having iridium as a central atom and phenylpyridine or a mono- or poly-substituted phenylpyridine derivative as a ligand.

[0154] Therefore, the reactive tape of the present invention according to the foregoing embodiments is also preferred, characterized in that the photo-oxidation-reduction catalyst comprises ruthenium as a central atom and bipyridine or a mono- or poly-substituted bipyridine derivative as a ligand, or

[0155] Iridium is used as the central atom and phenylpyridine or mono- or poly-substituted phenylpyridine derivatives are used as ligands.

[0156] The at least one photo-oxidation-reduction catalyst is preferably selected from: Ru (bpm) 2+ (e.g., tris(2,2'-bipyrimidine)ruthenium(II) chloride), Ru(bpz)3 2+ (e.g., tris(2,2'-bipyrazine)ruthenium bis(hexafluorophosphate)), Ru(bpy)3 2+ Ru(phen)3 2+ (For example, ruthenium(II) chloride trichlorotris(1,10-phenanthroline)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-pyridyl- N [Phenyl-C]iridium(III)hexafluorophosphate), Ir(ppy)2(dtbbpy) + (e.g., [Ir(dtbbpy)(ppy)2][PF6]), in each case adding one or two or more anions (i.e., counter anions to 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 copper complex dichloro(1,10-phenanthroline)copper(II) (CAS: 14783-09-6).

[0157] In a very particularly preferred embodiment of the invention, the photoredox catalyst is ruthenium(II) tris(2,2′-bipyridyl)chloride hexahydrate, Ru(bpy)3Cl2 6H2O.

[0158] The base composition preferably contains up to 1% by weight, particularly preferably 0.01% by weight to 0.5% by weight, and even more preferably 0.01% by weight to 0.1% by weight of a redox catalyst, preferably a photoredox catalyst, preferably a photoredox catalyst with ruthenium as the central atom and bipyridine or a mono- or poly-substituted bipyridine derivative as the ligand, or with iridium as the central atom and phenylpyridine or a mono- or poly-substituted phenylpyridine derivative as the ligand.

[0159] Other additives and / or auxiliaries

[0160] The base composition may optionally contain additional additives and / or auxiliaries known in the art. The proportions of the additional additives and / or auxiliaries may range from 0% to about 20% by weight, preferably from 0% to about 15% by weight, more preferably from 0% to about 10% by weight, and most preferably from 0% to about 5% by weight.

[0161] Other examples of additives and / or auxiliaries include, for example, fillers, dyes, nucleating agents, rheology modifiers (e.g., pyrolytic silica), foaming agents, adhesive reinforcing additives (adhesion promoters, especially silanes and tackifier resins), compounding agents, plasticizers and / or aging stabilizers, light stabilizers and UV stabilizers, for example in the form of primary and secondary antioxidants.

[0162] In particular, and according to a preferred embodiment, the filler, such as glass beads or SiLibeads® 5211, is in the proportion of up to 50% by weight, and especially up to 40% by weight.

[0163] In a preferred embodiment, the reactive adhesive composition comprises at least one rheology-modified filler, such as, in particular, silica, preferably in an amount of 1% to 10% by weight, and particularly preferably 2% to 5% by weight.

[0164] Reactive tape system

[0165] The present invention further provides a reactive tape system comprising at least one first reactive tape comprising at least one reactive curable adhesive composition layer D according to the present invention, and a second reactive tape comprising at least one reactive curable adhesive composition layer, wherein the at least one reactive curable adhesive composition layer D of the first reactive tape comprises at least one initiator and preferably does not comprise a redox catalyst, and the at least one reactive curable adhesive composition layer of the second reactive tape comprises at least one redox catalyst and preferably does not comprise an initiator, wherein the second reactive tape is preferably also a tape according to the present invention comprising at least one reactive curable adhesive composition layer D.

[0166] Preferably, a reactive tape system comprising at least one first reactive tape and a second reactive tape according to the invention is provided, wherein at least one reactive curable adhesive composition layer D of the first reactive tape comprises at least one initiator, and at least one reactive curable adhesive composition layer D of the second reactive tape comprises at least one redox catalyst.

[0167] The initiator of the tape system according to the present invention can be any of the aforementioned initiators, wherein all of the foregoing applies.

[0168] Iron phthalocyanine (II) is preferably used as a redox catalyst.

[0169] In the tape system according to the invention, reactive curing is initiated or activated solely by bringing the first reactive tape according to the invention into contact with the second reactive tape according to the invention.

[0170] Here, the initiator system consisting of a redox catalyst and an initiator is neither a photoinitiator nor a thermal initiator system that can be cured by heating.

[0171] It will be understood that, in all embodiments of the tape system according to the invention, the reactive curable adhesive composition layer D of the first reactive tape does not contain a redox catalyst that would initiate premature activation in the reactive curable adhesive composition layer D of the first reactive tape.

[0172] Similarly, the reactive adhesive composition layer D of the second reactive tape does not contain an initiator that is activated prematurely by a redox catalyst.

[0173] The present invention further provides an adhesive composite comprising at least the following layers: First base A; and Second basement B; and The reactive tape or reactive tape system according to the invention is disposed between substrate A and substrate B and bonds substrate A and B to each other.

[0174] The present invention further provides a method for electrically debonding the composite according to the invention, comprising at least the following method steps: i) Apply a voltage at two different points on the composite, wherein the voltage is preferably 2 to 50 V.

[0175] A voltage is applied according to step i.) of the method according to the invention to achieve electrodebonding of the composite.

[0176] Voltage, especially DC voltage.

[0177] In a preferred embodiment of the invention, the voltage is 3 to 12 V. Such a voltage can be applied, particularly by using a battery disposed close to the adhesive, for example, in mobile phones, tablet computers, etc.

[0178] In another preferred embodiment of the invention, the voltage is 12 to 50 V. This relatively high voltage allows for particularly rapid debonding; the voltage, especially up to 50 V, needs to be applied for only a few seconds.

[0179] Those skilled in the art know in principle how to apply voltage without causing an unwanted short circuit.

[0180] The duration of voltage application in step i.) depends particularly on the desired voltage and can range from only a few seconds, especially 2 seconds, up to 900 seconds, preferably up to 600 seconds, and particularly preferably up to 300 seconds.

[0181] It is also conceivable that the voltage would be applied for a period of time longer than 900 seconds, especially if the voltage is relatively low.

[0182] The method for electrodebonding the composite according to the invention allows for the rapid and simple debonding of substrates A and B from each other without applying excessive force.

[0183] If, after applying voltage, the layers do not detach from each other without further influence, the method according to the invention includes at least the following additional process steps: ii.) Apply force to adhesive composition layer D and / or substrate A and / or substrate B to increase the distance between substrates A and B.

[0184] The force that may still be needed in step ii.) is significantly less than the force required before the voltage was applied in step i.).

[0185] The voltage applied according to step i.) is performed at two different points on the bonded composite according to the invention. Advantageously, the points at which the voltage is applied depend on the construction of the tape or tape system and the bonded composite, and therefore on the composition of the individual layers and the substrates A and B to which they are bonded.

[0186] The following lists many preferred implementation methods.

[0187] In a preferred embodiment, the reactive tape according to the invention is a transfer tape and consists of an adhesive composition layer D.

[0188] When both substrates A and B are conductive, such an adhesive tape can advantageously re-electrodebond within an bonded composite comprising the two substrates A and B. To this end, a voltage is then applied to substrates A and B, causing anion migration to the anode and cation migration to the cathode within the adhesive composition. Not wishing to be bound by any particular theory, the inventors believe the following mechanism applies: the application of voltage leads to the migration of electrolytes in adhesive composition layer D, particularly the separation of anions and cations in ionic liquids. This results in a significant reduction in the adhesion of adhesive composition layer D to substrates A and B, facilitating the debonding of these layers from each other.

[0189] In a preferred embodiment of the present invention, the adhesive composition layer D contains at least one initiator and at least one redox catalyst, wherein the redox catalyst is preferably at least one photo-redox catalyst, and the adhesive composition layer D is preferably photocurable.

[0190] In a preferred embodiment, it is also conceivable to use the tape system according to the invention to bond two substrates A and B together, wherein the first and second tapes each serve as transfer tapes and consist of a respective reactive curable adhesive composition layer D. Thus, for example, the reactive curable adhesive composition layer D of the first tape contains at least one initiator and preferably does not contain a redox catalyst, while the reactive curable adhesive composition layer D of the second tape contains at least one redox catalyst and preferably does not contain an initiator.

[0191] The first and / or second tapes of the tape system may contain a permeable carrier structure that further allows the electrolyte, as well as the initiator and / or redox catalyst, to migrate, so as not to impair reactive curing when the two tapes come into contact with each other.

[0192] Such a permeable carrier structure is particularly suitable for woven fabrics or knitted fabrics made of textile fibers or metal threads, wherein the textile fibers may also be coated with metal.

[0193] Suitable examples include, for example, option b) a conductive textile containing at least one metal, preferably selected from copper and nickel, and / or d) at least one mesh made of metal.

[0194] Then, similarly, electrodebonding is performed on conductive substrates A and B.

[0195] In a preferred embodiment of the invention, the bonded composite therefore comprises the following layers: The first conductive substrate A; and The conductive second substrate B; and According to the present invention, the tape comprises an adhesive composition layer D and is disposed between a substrate A and a substrate B, thereby bonding the substrates A and B together. According to the invention, a tape system is formed by two transfer tapes according to the invention by bringing the tapes into contact with each other. The first tape contains at least one initiator and preferably does not contain a redox catalyst before contact, and the second tape contains at least one redox catalyst and preferably does not contain an initiator before contact, wherein the tape system is arranged between a substrate A and a substrate B and the substrates A and B are bonded together.

[0196] In another preferred embodiment, the reactive tape according to the invention comprises not only a first adhesive composition layer D, but also at least one second adhesive composition layer C.

[0197] In a particularly preferred embodiment of the invention, the second adhesive composition layer C is conductive. This configuration has the advantage that a voltage can be applied to the adhesive composition layer C, allowing the non-conductive substrate (in this case, substrate B) to debond electrically again.

[0198] In a preferred embodiment of the invention, the adhesive composition layer C protrudes laterally beyond the substrate to which it is bonded, such that a voltage can be applied to layer C from above (i.e., immediately adjacent to the substrate).

[0199] In a preferred embodiment of the invention, the substrate (here, substrate B) bonded to layer C contains pores, such that layer C of the adhesive composition also protrudes laterally beyond the substrate to which it is bonded. Here, a voltage may also be applied to layer C from above (i.e., immediately adjacent to the substrate).

[0200] The listed options are advantageous, especially when layer C is so thin that applying it from the side is not feasible. However, otherwise, a correspondingly thin electrode may also be used.

[0201] In a particularly preferred embodiment of the invention, the second adhesive composition layer C is also a reaction-curable adhesive composition layer. This allows the tape to be used in substrates or applications where high adhesive strength is desired with reaction-curable tapes, especially those capable of room-temperature curing. Therefore, the first and second adhesive composition layers D and C are also particularly compatible.

[0202] In a preferred embodiment of the present invention, the adhesive composition layer D contains at least one initiator and at least one redox catalyst, wherein the redox catalyst is preferably at least one photo-redox catalyst, and the adhesive composition layer D is preferably photocurable.

[0203] The tape according to the above embodiment preferably consists of layers D and C. The structure including a second adhesive composition layer is also referred to below as a two-layer composite DC.

[0204] In a preferred embodiment, layer D has the same dimensions as layer C in the xy plane, such that D and C can be processed together as a two-layer composite and, for example, die-cut.

[0205] In a preferred embodiment of the invention, the bonded composite therefore comprises the following layers: The first conductive substrate A; and Second basement B; and According to the present invention, the tape consists of two layers of composite DC that bond substrates A and B together, such that the adhesive composition layer D is bonded to the conductive substrate A.

[0206] As described above, substrate B does not need to be conductive. According to a preferred embodiment, substrate B is not conductive.

[0207] It is also conceivable that the tape system according to the invention could be used for bonding.

[0208] According to an advantageous embodiment, it is also conceivable to use a tape system comprising a first reactive curable adhesive composition layer D containing at least one electrolyte and at least one initiator but without a redox catalyst or a redox catalyst and without an initiator, and comprising a second reactive curable adhesive composition layer C without an electrolyte, wherein the second reactive curable adhesive composition layer contains at least one redox catalyst and without an initiator or at least one initiator and without a redox catalyst in a manner complementary to the first layer.

[0209] In another preferred embodiment of the invention, the bonded composite therefore comprises the following layers: The first conductive substrate A; and Second basement B; and The tape system according to the invention comprises at least one layer D of a reactive curable adhesive composition according to the invention.

[0210] In another preferred embodiment, the tape comprises not only the first adhesive composition layer D, but also at least the following layers: Second adhesive composition layer C; and At least one conductive carrier layer T is disposed between layers D and C.

[0211] Such an adhesive tape can be adapted to a variety of different substrates as a double-sided tape via the second adhesive composition layer C. In principle, it can involve the same substrates as those according to the foregoing embodiments, wherein the tape is a transfer tape.

[0212] However, such tape can also be used, particularly and advantageously, for subsequently separating substrates A and B from each other, wherein only one of the substrates is conductive, such as substrate A.

[0213] In a preferred embodiment, xi.) only the carrier layer T or xii.) the carrier layer T and the second adhesive composition layer C are configured to be conductive.

[0214] Therefore, voltage xi.) can be applied to the conductive carrier layer or xii.) can be applied to the second adhesive composition layer C and the conductive substrate A.

[0215] First, an adhesive tape, advantageously a double-sided tape, is used to bond an electrically detachable adhesive composition layer D to a conductive substrate A, and a second adhesive composition layer is bonded to a substrate B, which may, but need not, be conductive.

[0216] Unwilling to be bound by any particular theory, the inventors believe the following mechanism applies: the application of voltage causes the migration of electrolytes in the adhesive composition layer D, particularly the separation of anions and cations in the ionic liquid. This results in a significant reduction in the adhesion of the adhesive composition layer D to the substrate A, allowing these layers to detach from each other.

[0217] In a preferred embodiment of the invention, xi.) only the carrier layer is conductive. A voltage can be applied to it particularly easily, especially and preferably when the carrier layer protrudes laterally beyond at least one layer of the adhesive composition.

[0218] In another preferred embodiment of the invention, xii.) the carrier layer and the second adhesive composition layer C are conductive. This configuration has the advantage of allowing voltage to be applied to the adhesive composition layer C. Lateral protrusions in the carrier layer are not necessary. Therefore, the tape can be produced in a simple manner, especially since layers D, T, and C can be die-cut together.

[0219] The tape according to the above embodiment preferably consists of three layers: D, T, and C. Therefore, the term three-layer composite DTC is also used in the context of this application.

[0220] In a preferred embodiment of the invention, the bonded composite therefore comprises the following layers: The first conductive substrate A; and Second basement B; and The tape according to the invention comprises a three-layer composite DTC that bonds substrates A and B together, such that adhesive composition layer D is bonded to conductive substrate A.

[0221] It is also conceivable that the tape system according to the invention could be used for bonding.

[0222] In another preferred embodiment of the invention, the bonded composite therefore comprises the following layers: The first conductive substrate A; and Second basement B; and According to the invention, a tape system is formed by bringing two reactive tapes according to the invention into contact with each other. The first tape contains a three-layer composite DTC, and the second tape contains at least one reactive curable adhesive composition layer D according to the invention. The adhesive composition layer D of the first tape contains at least one initiator and preferably does not contain a redox catalyst before contact, and the adhesive composition layer D of the second tape contains at least one redox catalyst and preferably does not contain an initiator before contact. The tape system bonds substrates A and B to each other.

[0223] According to these embodiments, the second tape may be a transfer tape, which consists of an adhesive composition layer D containing the at least one redox catalyst prior to contact. Preferably, the tape system is an adhesive tape system in which the adhesive composition layer D of the second tape is adhered to the conductive substrate A.

[0224] In these embodiments, the second tape may additionally be a two-layer composite DC, wherein the adhesive composition layer D contains at least one redox catalyst prior to contact.

[0225] The second tape may also contain a three-layer compound DTC, with all the foregoing contents similarly applicable.

[0226] The adhesive composition layer C in all the above embodiments is preferably an adhesive composition layer that can be cured by photoreaction, and for this purpose contains at least one initiator and at least one redox catalyst, wherein the redox catalyst is at least one photoredox catalyst.

[0227] In another preferred embodiment, the tape comprises not only the first adhesive composition layer D, but also at least the following layers: Second adhesive composition layer C; and At least a first conductive carrier layer T, which is disposed between layers D and C; and At least one second conductive carrier layer T' is disposed on the surface of the adhesive composition layer D opposite to the first conductive carrier layer T; and A third adhesive composition layer C' is disposed on the surface of the second conductive carrier layer T' opposite to the first adhesive composition layer D.

[0228] Such a tape has at least a layered structure CTD-T'-C' and can be used as a double-sided tape for a variety of different substrates via adhesive composition layers C and C'.

[0229] In principle, this may involve the same substrate as that according to the foregoing embodiments, wherein the tape is a transfer tape or a DTC with a three-layer structure.

[0230] However, such tape can also be used, particularly and advantageously, to subsequently debond substrates A and B from each other, where neither of them is conductive.

[0231] In a preferred embodiment, xi.) only carrier layers T and T' or xii.) carrier layers T and T' and the second adhesive composition layer C and / or the third adhesive composition layer C' are conductive.

[0232] This allows voltage to be applied xi.) to either of the two conductive carrier layers or xii.) to at least one of the adhesive composition layers C and C', as well as to one of the carrier layers or other adhesive composition layers.

[0233] Similar to the embodiments described above, it is believed that the application of voltage causes the migration of electrolytes in the adhesive composition layer D, particularly the separation of anions and cations in the ionic liquid. Therefore, the adhesion of the adhesive composition layer D to the conductive carrier layers T and T' is significantly reduced, leading to the debonding of these layers from each other.

[0234] In a preferred embodiment of the invention, only the carrier layers T and T' are conductive. In particular, and preferably, when the carrier layers T and T' protrude laterally beyond at least one of the respective adjacent adhesive composition layers, a voltage can be applied to them particularly easily.

[0235] In another preferred embodiment of the invention (xii.), the carrier layers T and T', as well as the second and third adhesive composition layers C and C', are conductive. This configuration has the advantage of allowing voltage to be applied to the adhesive composition layers C and C'. Lateral protrusions in the carrier layers T and T' are not necessary. Therefore, the tape can be produced in a simple manner, especially since layers C, T, D, T', and C' can be die-cut together.

[0236] The tape according to the above embodiment preferably consists of five layers: C, T, D, T', and C'. Therefore, the term five-layer composite CTD-T'-C' is also used in the context of this application.

[0237] The adhesive composition layers C, D and C' are preferably, in each case, adhesive composition layers that can be cured by photoreaction, and for this purpose contain at least one initiator and at least one redox catalyst, said redox catalyst being at least one photoredox catalyst.

[0238] In a preferred embodiment of the invention, the bonded composite therefore comprises the following layers: First base A; and Second basement B; and The tape according to the invention consists of a five-layer composite CTD-T'-C' that bonds substrates A and B together.

[0239] Similarly, it is conceivable that in the bonded composite, the bonding of substrates A and B is achieved by the tape system according to the invention, wherein the first tape has a structure CTD prior to contact and the second tape has a structure D-T'-C', wherein the adhesive composition layer D of the first tape contains at least one initiator and preferably does not contain a redox catalyst prior to contact, and the adhesive composition layer D of the second tape contains at least one redox catalyst and preferably does not contain an initiator prior to contact.

[0240] The conductive substrate in all embodiments can be, for example, a metal casing for a mobile phone.

[0241] The non-conductive substrate in all embodiments may be a housing made of a non-conductive material such as plastic, or a battery, or other components such as a speaker that are non-conductive parts.

[0242] The present invention further provides the use of the tape or tape system according to the invention for bonding components in electronic, optical or precision mechanical devices, automobiles, medical devices and dental devices.

[0243] The reactive tapes or tape systems according to the invention are preferably used to produce adhesion to materials selected from plastics, metals, glass or ceramics, and as adhesives in the production of electronic, optical or precision mechanical devices.

[0244] Such portable devices specifically include: Cameras, digital cameras, photography accessories (such as exposure meters, flashes, apertures, camera bodies, lenses, etc.), film cameras, video cameras, microcomputers (mobile computers, pocket computers, calculators), laptop computers, notebooks, netbooks, ultrabooks, tablet computers, handheld devices, electronic diaries and notebooks (so-called electronic notebooks or personal digital assistants, PDAs, handheld computers), modems. Computer peripherals and user interfaces used for electronic devices, such as mice, drawing tablets, graphics input tablets, microphones, speakers, game consoles, game controllers, remote controls, and touchpads; Monitors, displays, screens, touchscreens (touchscreens, touchscreen devices), projectors; E-book reader (e-book); Portable TVs, pocket TVs, movie players, video players, radios (including portable and pocket radios), Walkmans, record players (CD players, Discmans), music players (for CD, DVD, Blu-ray, cassette tape, USB, MP3), headphones, cordless phones, mobile phones, smartphones, radios, hands-free devices, paging devices (pagers, pagers). Portable defibrillator, blood glucose meter, blood pressure monitor, pedometer, heart rate monitor; Flashlight, laser pointer; Motion detectors, optical magnifying glasses, binoculars / telescopes, night vision devices, GPS devices, navigation devices, portable satellite communication interface devices; Data storage devices (USB flash drives, external hard drives, memory cards); and wristwatches, digital watches, pocket watches, chain watches, and stopwatches.

[0245] In all the foregoing embodiments, the carrier layer T, as well as T and T', is conductive.

[0246] These layers are described in more detail below. For simplicity, the term "conductive carrier layer" or simply "carrier layer" will be used. According to the above embodiments, this refers to carrier layer T or carrier layers T and T'.

[0247] The carrier layers T and T' are independent of each other and may be the same or different.

[0248] The conductive carrier layer preferably contains at least one metal.

[0249] The metal is particularly preferably selected from copper, nickel, zinc, tin, silver, gold, aluminum, iron, chromium, and alloys of these metals. The metal is very particularly preferably selected from aluminum, zinc, copper, and nickel. Aluminum is very particularly preferred.

[0250] The conductive carrier layer preferably has a layer thickness of 10 nm (nanometer) to 50 μm (micrometer) measured in the z-direction (i.e., parallel to the stacking direction of the layer assembly).

[0251] In a preferred embodiment of the invention, the conductive carrier layer comprises: a) at least one metal foil, preferably aluminum foil, and / or b) at least one conductive textile containing at least one metal, preferably selected from copper and nickel, and / or c) one or more layers of at least one vapor-deposited metal, preferably selected from copper and aluminum, and / or d) at least one mesh made of metal, and / or e) a film vapor-deposited with metal.

[0252] In principle, it is also possible to consider layer T as a combination of two or more of the listed options.

[0253] Metal foil, such as, and preferably, aluminum foil, is known to those skilled in the art.

[0254] The metal foil, such as and preferably aluminum foil, preferably has a layer thickness of 5 to 50 μm, particularly preferably 10 to 30 μm, measured in the z-direction (i.e., the stacking direction parallel to the layer arrangement).

[0255] Conductive textiles are known to those skilled in the art, especially by the term "conductive mesh". This refers to textile fabrics, for example, made of PET (polyethylene terephthalate), coated with metals, such as copper and / or nickel, to produce conductivity in the fabric.

[0256] It is also known to those skilled in the art that metals can be directly vapor-deposited on surfaces, such as the surface of adhesive composition layers, as a single layer or multiple layers.

[0257] In the context of this invention, the conductive carrier layer can be provided by depositing a metal vapor phase onto the adhesive composition layer D, the adhesive composition layer C, or the adhesive composition layer C'.

[0258] Mesh made of metal of different sizes is also known to those skilled in the art. Metal meshes of suitable layer thickness can be produced, for example, via a non-curling fabric of correspondingly thin metal wires or by die-cutting foil of at least one corresponding layer thickness.

[0259] In the case of a metal-coated film, the non-conductive film is particularly made conductive by metal vapor deposition. The film material can, in principle, be any material suitable for metal vapor deposition and use as a carrier film in an adhesive tape. Materials are particularly selected from polyesters and polyolefins, with mixtures of various materials also conceivable. Preferred polyesters particularly include polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). Preferred polyolefins particularly include polypropylene (PP) and polyethylene (PE). In a preferred embodiment, the film material is selected from PET, PEN, PE, and PP.

[0260] Preferably, this involves a PET (polyethylene terephthalate) film. Such a film is dimensionally stable and therefore easy to process without undergoing significant stretching or tearing. This allows for the permanent application of a uniform and gapless metal layer, thereby permanently ensuring conductivity throughout the film, especially in the z-direction.

[0261] In embodiments where at least one conductive carrier layer T or at least two conductive carrier layers T and T' are present, it is preferred that the at least one adjacent adhesive composition layer protrudes laterally in at least one extending direction of the layer plane and thus exhibits a lateral protrusion. A voltage can then be applied to this lateral protrusion in a simple manner.

[0262] In the case of a five-layer composite, the lateral protrusions of the conductive carrier layers T and T' are arranged spaced apart from each other in an advantageous embodiment. This makes it easy to apply a voltage to these protrusions.

[0263] When a vapor-deposited metal is used as a carrier layer, it is preferable that the carrier layer protrudes laterally beyond only one adjacent adhesive composition layer in at least one extending direction of the layer plane, and the corresponding other adhesive composition layer acts as a mechanical support for the metal layer. In this case, the metal layer does not have a practical carrier function. Instead, the other adhesive composition layer serves as the carrier for the metal layer. However, for simplicity, the term carrier layer is also retained for the metal layer in these embodiments. In this case, the layer thickness of layer T is preferably not less than 10 nm, preferably 50 to 200 nm.

[0264] In a preferred embodiment of the invention, the conductive carrier layer T or T and / or T' comprises: a) at least one metal foil, preferably aluminum foil, and / or b) at least one conductive textile comprising at least one metal, preferably selected from copper and nickel, and / or d) at least one mesh made of metal, and / or e) a film vapor-deposited with metal, and protruding beyond the first adhesive composition layer D and the second adhesive composition layer C or the first adhesive composition layer D and the second adhesive composition layer C and / or the first adhesive composition layer D and the third adhesive composition layer C' in at least one extending direction.

[0265] This allows voltage to be applied to the carrier layer in a simple and reliable manner. Meanwhile, the tape can be produced in a relatively simple way.

[0266] In a preferred embodiment of the invention, the conductive carrier layer T or T and / or T' comprises one or more layers of at least one vapor-deposited metal, preferably one layer, wherein the metal is preferably selected from copper and aluminum.

[0267] In a particularly preferred embodiment of the invention, the conductive carrier layer T or T and / or T' comprises e) a film with metal vapor-deposited on it, and protrudes beyond the first adhesive composition layer D in at least one extension direction. The film has metal vapor-deposited on one surface in particular, and the corresponding carrier layer is bonded to the first adhesive composition layer D via a metallized surface, and thus to a layer capable of electrical debonding.

[0268] This allows voltage to be applied to the carrier layer in a simple and reliable manner.

[0269] In the context of this invention, the expression "laterally protruding" is understood to mean any type of lateral protrusion of one or more layers in discussion, and that the layers in discussion extend further than the cover layer in each case, particularly in the "xy" plane and therefore laterally—perpendicular to the stacking direction. Instead of the term "laterally protruding," the terms "laterally extending" or "laterally extending segment" are also used in the context of this invention.

[0270] The term "lateral" here refers to the direction of extension of the layer plane "xy" perpendicular to the stacking direction "z" of the layers. Therefore, this term is particularly independent of the geometry of the tape in the "xy" plane, which can be, for example, a rectangle as is common for tape (see above), but can also be a square or a circle.

[0271] We will not discuss here the minute variations in the dimensions of the individual layers in the “xy” plane caused by die-cutting or similar forming processes, especially since such minute material protrusions are unsuitable for the planned application of voltage to them due to their size.

[0272] Adhesive composition layer C or C and C' may, in principle, be based on the same composition as adhesive composition layer D, wherein the adhesive composition of layer C or C and C' does not need to, but may contain, an electrolyte. Layer C or C and C' preferably does not contain an electrolyte.

[0273] In some embodiments of the two-layer composite DC described above, the adhesive composition layer C is conductive.

[0274] In some embodiments of the three-layer composite DTC described above, the adhesive composition layer C is conductive.

[0275] Similarly, the adhesive composition layer C and / or adhesive composition layer C' of the five-layer composite CTD-T'-C' can also be conductive.

[0276] These layers are described in more detail below. For simplicity, the term "conductive adhesive composition layer" will be used where appropriate. According to the above embodiments, this refers to adhesive composition layer C or adhesive composition layers C and / or C'. For simplicity, the expression "adhesive composition layer C or C and / or C'" will also be used, which is understood to mean the corresponding layer in the described embodiments of an adhesive tape comprising at least two layers, three layers, or at least five layers of the composite.

[0277] The adhesive composition layers C and C' are independent of each other and may be the same or different.

[0278] All of the foregoing also applies to the tape system according to the present invention.

[0279] Therefore, the conductive adhesive composition layer preferably contains at least one metal, such as nickel, copper, or silver, preferably in the form of conductive metal particles and / or metallized particles, particularly preferably metal particles.

[0280] The metallized particles are, in particular and preferably, glass or polymer particles metallized with at least one metal, such that the originally non-conductive particles are configured to be conductive through metallization.

[0281] The conductive adhesive composition layer particularly preferably comprises conductive particles selected from nickel particles, copper particles and silver-plated copper particles.

[0282] In a particularly preferred embodiment, the conductive adhesive composition layer contains nickel particles.

[0283] The conductive adhesive composition layer preferably comprises 5% to 65% by weight, particularly preferably 20% to 62% by weight, conductive particles, especially metal particles and / or metallized particles, based on the total mass of the adhesive composition.

[0284] The conductive particles should preferably be no larger than or not significantly larger than the corresponding thickness of the conductive adhesive composition layer in the z-direction as measured by an optical microscope.

[0285] The conductive particles preferably have an average particle size of 1 to 10 μm, particularly preferably 1 to 6 μm, and even more preferably 3 to 5 μm, for example, especially 4 μm.

[0286] The conductive adhesive composition layer is conductive, especially at least in the z-direction.

[0287] However, it can also conduct electricity in the xy plane. In preferred embodiments where a conductive adhesive composition layer is configured to conduct electricity only in the z-direction, and not necessarily in the xy-direction, a smaller amount of these materials is required to achieve conductivity by adding metal, especially metal particles. This ensures that the adhesive composition is optimized in terms of desired conductivity, bond strength, flow behavior, and cost.

[0288] In the context of this invention, the layer is considered "conductive", especially when the resistance measured in the corresponding direction (particularly in the z-direction) according to standard MIL-DTL-83528C is less than 1 ohm.

[0289] The following applies regardless of whether the adhesive composition layer C or C and / or C' is configured to be conductive.

[0290] In a preferred embodiment of the invention, adhesive composition layer C or C and / or C' is a reaction-curable adhesive composition, especially a light-curable adhesive composition, similar to adhesive composition layer D.

[0291] In a preferred embodiment of the invention, adhesive composition layer C or C and / or C' uses the same polymer and the same reactive monomers or oligomers and corresponding initiator system as adhesive composition layer D.

[0292] This makes it especially possible to bond similar substrates (here referred to as A and B) to each other.

[0293] In another preferred embodiment of the invention, adhesive composition layer C or C and / or C' uses an adhesive composition different from that of adhesive composition layer D.

[0294] This allows the properties of the conductive layer to be adapted particularly easily to the substrate bonded via adhesive composition layer C or C and / or C'. Since adhesive composition layer C or C and / or C' preferably does not contain or does not need to contain electrolytes such as ionic liquids, the composition does not need to be adapted thereto.

[0295] Preferably, the adhesive composition of the adhesive composition layer D is a pressure-sensitive adhesive, and therefore preferably a pressure-sensitive adhesive composition, and therefore the adhesive composition layer D is preferably a pressure-sensitive adhesive composition layer D.

[0296] This is beneficial for the processability and application of the tape, especially in embodiments where the adhesive composition layer D is used as a transfer tape.

[0297] Pressure-sensitive adhesive properties allow reactive pressure-sensitive tapes to be reliably and safely applied to a substrate before curing.

[0298] In a preferred embodiment, the adhesive composition of adhesive composition layer C or C and / or C' is also a pressure-sensitive adhesive composition.

[0299] In the present context of the invention, as is generally understood, pressure-sensitive adhesives are understood to refer to substances, particularly those that are permanently tacky and adhesive at room temperature. Pressure-sensitive adhesive compositions are characterized by their ability to be applied to a substrate and remain adhered there, wherein the applied pressure and the duration of its application are not otherwise defined. In some cases, depending on the exact properties of the pressure-sensitive adhesive, temperature and atmospheric humidity, and the substrate, a short period of minimal pressure (not exceeding brief, slight contact) is sufficient to achieve an adhesive effect, while in other cases, a longer duration of high pressure may be required.

[0300] Pressure-sensitive adhesives possess specific viscoelastic characteristics that lead to permanent tackiness and adhesiveness. These are characterized by the fact that, when they are mechanically deformed, they undergo both a viscous flow process and the accumulation of elastic restoring forces. The two processes are proportional to each other in their respective proportions, which depends not only on the exact composition, structure, and degree of crosslinking of the pressure-sensitive adhesive, but also on the rate and duration of deformation and the temperature.

[0301] Proportional viscous flow is essential for adhesion. Only viscous components brought about by relatively highly mobile macromolecules allow for good wetting and flow to the substrate to be bonded. High proportions of viscous flow result in high pressure-sensitive adhesive tack (also known as tack or surface tack), and therefore often also high adhesive strength. Due to the lack of free-flowing components, highly cross-linked systems, crystalline or glassy cured polymers generally exhibit at least slight pressure-sensitive adhesion (if any).

[0302] Proportional elastic restoring forces are necessary for achieving cohesion. They are caused, for example, by very long chains and strongly entangled macromolecules, as well as by physically or chemically cross-linked macromolecules, and are capable of transferring forces acting on adhesive bonds. They have the effect that adhesive bonds can withstand permanent loads acting on them, for example, in the form of permanent shear loads, over long periods of time to a sufficient extent.

[0303] The variable storage modulus (G') and loss modulus (G''), which can be determined by dynamic mechanical analysis (DMA, according to DIN EN ISO 6721), can be used to more accurately describe and quantify the elastic and viscous proportions, as well as the ratios of these proportions to each other. G' is a measure of the elastic proportion of a substance, and G'' is a measure of the viscous proportion. Both variables depend on the deformation frequency and temperature.

[0304] A rheometer can be used to measure the deformation. The material to be examined, for example, is subjected to sinusoidal oscillating shear stress in a plate-plate assembly. In an instrument controlled by shear stress, the deformation is measured as a function of time and the time delay of that deformation relative to the time delay in which the shear stress was introduced. This time delay is called the phase angle δ.

[0305] The energy 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 vectors).

[0306] The loss modulus G'' is defined as: G' = (τ / γ) sin(δ) (τ = shear stress, γ = deformation, δ = phase angle = phase shift between shear stress and deformation vectors).

[0307] If at room temperature, according to the definition of the present invention at 23°C, at 10 0 Up to 10 1 Within the deformation frequency range of radians per second, G' is at least partially within 10 3 Up to 10 7 If a substance is within the range of Pa and G'' is also at least partially within that range, then the substance is generally considered a pressure-sensitive adhesive and, in the context of this invention, is defined as a pressure-sensitive adhesive. The term "partially" is understood to mean that at least a portion of the G' curve spans 10... 0 Up to 10 1 The range of deformation frequencies in radians per second (including endpoints) (x-axis) and 10 3 Up to 10 7 The range of G' values ​​(vertical axis) for Pa (including endpoints) is within the window. This applies accordingly to G".

[0308] At 23℃ at 10 0 Up to 10 1 Within the deformation frequency range of radians per second, the pressure-sensitive adhesive preferably has a value of 10 radians per second as determined according to DIN EN ISO 6721. 3 Up to 10 7 Storage modulus G' and loss modulus G'' within the Pa range.

[0309] To achieve viscoelasticity, the monomers upon which the polymer forming the pressure-sensitive adhesive is based and other components of the pressure-sensitive adhesive that may be present are selected such that the pressure-sensitive adhesive has a glass transition temperature (according to DIN 53765) below the service temperature (i.e., typically below room temperature (23°C)). Suitable cohesive strengthening measures, such as crosslinking reactions (forming bridging bonds between macromolecules), allow for the expansion and / or modification of the temperature range in which the polymer composition exhibits pressure-sensitive adhesive properties. Therefore, the application range of the pressure-sensitive adhesive can be optimized by adjusting the balance between the flowability and cohesiveness of the composition.

[0310] Pressure-sensitive adhesives, in particular, have a glass transition temperature of ≤23°C as determined according to DIN 53765.

[0311] For simplicity, the inventors define, in the context of this invention, the reactive pressure-sensitive tape preferably has an adhesive force of at least 1 N / cm in its uncured state and is removed with almost no residue (i.e., adhesive failure in the test). The adhesive force on steel is measured similarly to ISO 29862:2007 (Method 3) at 23°C and 50% relative humidity at a peel rate of 300 mm / min and a peel angle of 180°. The reinforcing film used is an etched PET film with a thickness of 36 μm, for example, available from Coveme (Italy). Adhesion of test strips with a width of 2 cm is performed using a roll-on machine at 23°C with a load of 4 kg. The tape is peeled off immediately after application. The measurements (in N / cm) are the average of three individual measurements. Cohesive failure in this test is demonstrated by the adhesive or tape, which is tacky at room temperature and whose cohesiveness is insufficient for residue-free removal. Such adhesives or tapes are not pressure-sensitive adhesives in the context of this invention.

[0312] The present invention also provides the production of the tape according to the invention.

[0313] The adhesive composition of layer D and, depending on the embodiment, additional adhesive compositions are produced by known methods and formed in layer form, particularly by spreading.

[0314] One or more drying steps may also be optionally performed.

[0315] The reactive tapes according to the invention are manufactured, particularly in the presence of a photoredox catalyst, while excluding UV or visible light, especially violet and blue light, of wavelengths that excite the corresponding initiator system or the corresponding photoredox catalyst. These are generally wavelengths less than 500 nm. Exclusion can generally be achieved using commercially available warm light lamps and by covering a normal light source having a UV component and / or violet and blue components in its wavelength spectrum with a commercially available UV-protective warm light film.

[0316] Adhesive composition layer D is produced, in particular, by the following method steps: In the first step, the components (constituents) are dissolved or finely distributed in one or more organic solvents and / or water. Suitable solvents are known in the art, and solvents in which at least one component has good solubility are preferred. Acetone and methyl ethyl ketone (MEK) are particularly preferred.

[0317] As used herein, the term "component" includes at least: a) at least one polymer, b) at least one monomer or oligomer capable of free radical polymerization, c) at least one initiator, d) at least one redox catalyst, e) at least one electrolyte, and optional additional components, such as rheology-modified fillers, in each case as defined above.

[0318] Then, in the second step, a conventional stirring device is used to mix the dissolved or finely distributed components. Optionally, the components are dissolved, finely distributed, and mixed simultaneously.

[0319] It is also conceivable to first prepare a base composition and then mix the composition with at least one electrolyte (e).

[0320] In each case, in the third step, a film, foil, layer, carrier, adhesive film, pressure-sensitive adhesive film, preferably a release liner or release paper, is coated with a mixture of dissolved, finely distributed components. The coating is performed using conventional techniques known in the art.

[0321] After coating, the solvent is removed by evaporation in the fourth step. Depending on the solvent used, this is preferably carried out in a temperature range of 60°C to 80°C.

[0322] The resulting layer or the reactive tape according to the invention is covered with a release liner or release paper for storage.

[0323] The lamination of multiple layers on top of each other is carried out in a manner known to those skilled in the art, wherein the layers are placed on top of each other in such a manner that a layer composite DC or DTC (where T is arranged between D and C) or C'-T'-DTC is obtained as a double-sided tape.

[0324] As explained above, the carrier layer T or T' can be provided in various ways.

[0325] Therefore, it is conceivable to place a) a metal foil, especially aluminum foil, and / or b) a conductive mesh and / or d) at least one mesh made of metal and / or e) a PET film with metal vapor-deposited on it between the respective adhesive composition layers.

[0326] Alternatively, metal particles can be directly vapor-deposited onto the surface of adhesive composition layer D, C, or C'.

[0327] The present invention further provides the production of bonded composites using tapes according to the invention.

[0328] The method according to the invention for producing an adhesive composite using the reactive tape according to the invention and therefore for bonding two substrates, preferably at room temperature, comprises the following steps: A) Apply reactive tape to the first substrate.

[0329] B) The reactive tape is activated by irradiation with UV light or blue light, preferably by irradiation with a UV-LED lamp, wherein the blue light has, in particular, and for example, a wavelength of 460 nm.

[0330] C) Bond the second substrate to the reactive tape.

[0331] The tape according to the invention may be selected from any of the described embodiments. In each case, the tape according to the invention comprises at least one reactive curable adhesive composition layer D, which is activated according to step B) of the method for producing the bonded composite.

[0332] The activation in step B) can be performed before or after step A).

[0333] The activation in step B) is preferably performed before step C), especially if activation via the first and second substrates is not possible.

[0334] In this method, especially when carried out on an industrial scale, irradiation is preferably performed at a wavelength of 365 mm or 385 nm, more preferably at 365 nm.

[0335] Irradiation can also be performed using a 460 nm LED radiation source. The result achieved by irradiating with 460 nm light is equivalent to irradiation with light at a wavelength of 365 nm or 385 nm.

[0336] In embodiments where the additional layers C or C' are configured to react and cure, these are also activated accordingly, preferably by irradiation with UV or blue light according to step B).

[0337] In the same case, those skilled in the art will adapt the timing of the steps to the corresponding substrate and the composition and structure of the corresponding tape.

[0338] Furthermore, the method according to the invention for producing an adhesive composite and thus bonding two substrates using the reactive tape system according to the invention, preferably at room temperature, comprises the following steps: X1) Provides a first adhesive tape according to the invention, which contains at least one initiator in a reactive curable adhesive composition layer D; and X2) A second adhesive tape according to the invention is provided, which contains at least one redox catalyst in a reactive curable adhesive composition layer D; and X3) provides the first substrate; and X4) provides a second substrate; and X5) Apply the first adhesive tape according to the invention to the first substrate; and X6) Apply the second adhesive tape according to the invention to the second substrate; and X7) Make the first tape according to the invention come into contact with the second tape according to the invention.

[0339] Steps X1) through X7) can be performed in any desired order, and thus the contact between the two tapes can be performed after or before application to the respective substrates.

[0340] In the same case, those skilled in the art will adapt the timing of the steps to the corresponding substrate and the composition and structure of the corresponding tape.

[0341] According to the present invention, particularly double-sided tapes, in an embodiment, both surfaces of the adhesive composition layer D (transfer tape), or one surface of the first adhesive composition layer D and one surface of the second adhesive composition layer C (two-layer composite DC or three-layer composite DTC), or one surface each of adhesive composition layers C and C' (five-layer composite CTD-T'-C') can be used to bond a substrate.

[0342] The outer exposed surfaces of the adhesive composition layer of the tape according to the invention may advantageously be provided with an abhesive material, such as release paper or release film, also known as a liner. The liner may also be a material with an abhesive coating on at least one side, preferably both sides, such as a double-sided silicone-coated (siliconized) material. The liner, or more generally a temporary carrier, is not a component of the tape, but merely an aid for its production, storage, and / or further processing by die-cutting. Furthermore, unlike a permanent carrier, the liner is not firmly bonded to the adhesive layer, but rather serves as a temporary carrier, i.e., a carrier that can be peeled off from the adhesive layer. In this application, "permanent carrier" is also simply referred to as "carrier."

[0343] The thickness (in the z-direction) of the individual adhesive composition layer is preferably 10 to 300 µm, particularly preferably 15 to 150 µm, very particularly preferably 20 to 100 µm, and very particularly preferably 25 to 70 µm.

[0344] In embodiments of the two-layer composite DC, the three-layer composite DTC, and the five-layer composite CTD-T'-C', according to a preferred embodiment, adhesive composition layers D and C, or D and C and D and C', have different layer thicknesses, wherein the thickness of adhesive composition layer D is, for example, less than the thickness of adhesive composition layers C or C and C'.

[0345] In another preferred embodiment, layers D and C, or D, C and C', have the same layer thickness.

[0346] If the thickness of layer D is too high, it may become impractically expensive due to the presence of electrolytes.

[0347] Preferred embodiments of the invention will now be illustrated and described in more detail with reference to the accompanying drawings. In the drawings: Figure 1 A simplified schematic cross-sectional view of the double-sided adhesive tape of the present invention according to a preferred embodiment is shown; and Figure 2 A simplified schematic cross-sectional view of the double-sided adhesive tape of the present invention according to a preferred embodiment is shown; and Figure 3 A simplified schematic cross-sectional view of the double-sided adhesive tape of the present invention according to a preferred embodiment is shown; and Figure 4 A simplified schematic cross-sectional view of the bonded composite of the present invention according to a preferred embodiment is shown; and Figure 5 A simplified schematic cross-sectional view of the bonded composite of the present invention with a voltage applied in a preferred embodiment is shown; and Figure 6 A simplified schematic cross-sectional view of the bonded composite of the present invention is shown after voltage has been applied and adhesive cracking has therefore occurred; and Figure 7 A simplified schematic cross-sectional view of the bonded composite of the present invention according to a preferred embodiment is shown; and Figure 8 A simplified schematic cross-sectional view of the bonded composite of the present invention according to a preferred embodiment is shown.

[0348] Figure 9 A simplified schematic cross-sectional view of the double-sided adhesive tape of the present invention according to a preferred embodiment is shown; and

[0349] Figure 10 A simplified schematic cross-sectional view of the bonded composite of the present invention with a voltage applied in a preferred embodiment is shown; and

[0350] Figure 11A simplified schematic cross-sectional view of the bonded composite of the present invention is shown after voltage has been applied and adhesive cracking has therefore occurred.

[0351] like Figure 1 Clearly, adhesive composition layer D1 is bonded to carrier layer T2 via one of its surfaces. A second adhesive composition layer C3 is disposed on the surface of carrier layer T opposite to layer D.

[0352] like Figure 1 Similarly, it is evident that the layered composite is a double-sided tape, wherein the surface of the adhesive composition layer D and the surface of the second adhesive composition layer C are each available for adhesive bonding.

[0353] Figure 2 A preferred embodiment of the invention is shown. Here, the conductive carrier layer T2 protrudes laterally beyond the adhesive composition layer D1 and the second adhesive composition layer C3 in at least one extending direction of the layer plane, resulting in the conductive carrier layer T2 exhibiting a protrusion having at least one free surface 2a.

[0354] Figure 3 Another preferred embodiment of the invention is shown. Here, the conductive carrier layer T2 protrudes laterally beyond the adhesive composition layer D1 in at least one extending direction of the layer plane, resulting in the conductive carrier layer T2 exhibiting a protrusion with a free surface 2a. Figure 3 In this configuration, adhesive composition layer C3 is prepared such that it also exhibits a protrusion relative to layer D1. The carrier layer T2 is, in particular, a PET film with aluminum coated on one side, wherein the aluminum-coated side is bonded to layer D1.

[0355] Figure 4 A schematic diagram of the bonded composite of the present invention according to a preferred embodiment is shown. (See from...) Figure 4 Clearly, the tape is disposed on the surface of the first substrate A4 via the adhesive composition layer D1, wherein the first substrate is conductive.

[0356] The tape is further disposed on the surface of the second substrate B5 via a second adhesive composition layer C3.

[0357] Figure 4 Similarly, by way of example, the conductive carrier layer T2 protrudes laterally beyond the adhesive composition layer D1 in at least one extending direction of the layer plane, resulting in the conductive carrier layer T exhibiting a protrusion with a free surface 2a.

[0358] A voltage can now be applied through this free surface 2a, such as Figure 5 As shown in the diagram.

[0359] The application of voltage causes the migration of electrolytes in the adhesive composition layer D1, especially the separation of anions and cations of ionic liquids.

[0360] Therefore, the adhesion of adhesive composition layer D1 to substrate A4 is significantly reduced, allowing these layers to debond from each other, as from Figure 6 The diagram is clear.

[0361] Figure 7 Further schematic diagrams of the bonded composite of the present invention according to a preferred embodiment are shown. (See from...) Figure 7 Clearly, the tape is disposed on the surface of the first substrate A4 via the adhesive composition layer C3.

[0362] The tape is further disposed on the surface of the second substrate B5 via a third adhesive composition layer C'7.

[0363] An electrically debonded adhesive composition layer D1 and two conductive carrier layers T2 and T'6 are arranged between layers C3 and C'7, wherein layer D1 is arranged between the carrier layers.

[0364] Figure 7 Similarly, conductive carrier layer T2 and conductive carrier layer T'6 are shown to each protrude laterally beyond adhesive composition layer D1 in at least one extending direction of the layer plane, such that conductive carrier layer T exhibits a protrusion having a free surface 2a, and conductive carrier layer T' exhibits a protrusion having a free surface 6a.

[0365] Figure 8 A further schematic diagram of the bonded composite of the present invention according to a preferred embodiment is shown, which is similar to... Figure 7 The illustration. However, with Figure 7 In contrast, the protrusions of conductive carrier layer T2 and conductive carrier layer T'6 point in different directions, causing the resulting free surfaces of these layers 2a and 6a to be spaced apart.

[0366] A voltage can now be applied through these free surfaces 2a and 6a, similar to... Figure 5 .and Figure 5 In contrast to the implementation method, voltage can be applied to surfaces 2a and 6a, so that neither substrate A nor B needs to be conductive.

[0367] The application of voltage causes the migration of electrolytes in adhesive composition layer D1, particularly the separation of anions and cations in the ionic liquid. Consequently, the adhesion of adhesive composition layer D1 to carrier layers T2 and / or T'6 is significantly reduced, leading to debonding of these layers from each other. Debonding occurs particularly at the layers where the negative terminal is applied.

[0368] exist Figure 8The application of voltage is simplified in the case of spaced surfaces 2a and 6a.

[0369] Figure 9 This is a schematic diagram of a two-layer composite consisting of an adhesive composition layer D1 that is electrically debonded and therefore contains an electrolyte, and a second adhesive composition layer C3.

[0370] Preferably, the second adhesive composition layer is conductive, especially in this embodiment.

[0371] This results in the ability to apply a voltage to it, such as Figure 10 This is shown schematically. Similarly, as... Figure 10 As shown, the conductive layer C3 protrudes laterally beyond the substrate 5, thus providing a free surface 3a to which a voltage can be applied. Therefore, at the point where a voltage is applied to layer C, layer C is arranged adjacent to the substrate 5, and not from that side (the application).

[0372] Here, applying voltage also reduces the adhesion of adhesive composition layer D1 to substrate A4, causing the substrate and adhesive composition layer to detach from each other, as... Figure 11 As shown in the image.

[0373] As explained above, Figures 1 to 11 The illustrations are schematic. The individual layers D, T, and C may have different thicknesses than each other. Substrates A and B are also shown only schematically as separate layers. It will be understood that these may have any other spatial geometry.

[0374] Several embodiments will now be described to further illustrate the invention.

[0375] Test methods

[0376] Unless otherwise specified, all measurements were performed at 23°C and 50% relative humidity. Mechanical and adhesive data were determined as follows: Molecular weight M n 、M w The number-average molecular weight M reported in this document n and weight average molecular weight M w The determination involved gel permeation chromatography (GPC). 100 μl of transparently filtered sample (sample concentration 4 g / L) was analyzed. The eluent used was tetrahydrofuran containing 0.1% (v / v) trifluoroacetic acid. Measurements were performed at 25 °C. The pre-column used was a PSS-SDV type column, 5 μm, 10... 3 Å, 8.0 mm 50 mm (Data in this and below are in the following order: type, particle size, porosity, inner diameter) Length; 1 Å = 10 –10 Separation was performed using a combination of PSS-SDV type columns, 5 μm, 10 m). 3 Å and 10 5 Å and 10 6 Å, with 8.0 mm in each case. 300 mm dimension (column from Polymer Standards Service; measured using a Shodex RI71 differential refractometer). Flow rate: 1.0 ml / min. Calibrate relative to PMMA standards (polymethyl methacrylate calibration) for polar molecules, otherwise calibrate relative to PS standards (polystyrene calibration).

[0377] thickness

[0378] The thickness of the adhesive composition layer can be determined by measuring the thickness of a cross-section of the adhesive composition layer applied to a pad defined in its length and width, and subtracting the thickness (known or individually determineable) of a cross-section of the same size pad used. The thickness of the adhesive composition layer can be determined with an accuracy of less than 1 μm using a commercially available thickness tester (touch tester). If thickness variation is measured, the average value of the measurements at at least three representative locations should be reported, especially excluding measurements at pinches, folds, spots, etc.

[0379] Similar to the thickness of adhesive composition layers, the thickness of tape (strip) or carrier can also be determined with an accuracy of less than 1 μm using a commercially available thickness tester (touch tester). If thickness variation is measured, report the average measurement at at least three representative locations, especially avoiding measurements at creases, folds, spots, etc.

[0380] Launch (SUS-SUS) – Initial (Adhesive Strength)

[0381] The test provides information on the adhesive strength of the adhesive product in the normal direction of the adhesive layer. A first circular substrate (1) (SUS, VA-1.4301 steel (single-sided mirror polished), 3 mm thick) with a diameter of 21 mm is provided; a second square substrate (2) (SUS, VA-1.4301 steel (single-sided mirror polished), 2 mm thick) with a side length of 40 mm and a centrally located circular opening (hole) with a diameter of 9 mm is provided; and a sample of adhesive tape to be tested is die-cut into a ring with an outer diameter of 18 mm and an inner diameter of 13 mm to form a ring with a material width of 5 mm.

[0382] Test specimens were produced using the three components described above by centrally bonding the adhesive product to the substrate (1) via a free surface. The temporary protective film (silicified PET liner) was then removed, and a blue LED (LEDSpot 100 HP IC 460 nm from Hönle AG) was used at a minimum of 50 J / cm². 2 Irradiation. Activation can also be performed using a 365 nm UV LED (Hönle AG).

[0383] Within 2 minutes, the compound is concentrically applied to the substrate (2) with the adhesive product now exposed, i.e., in such a way that the circular cutout of the substrate (2) is precisely centered above the circular first substrate 1 (thus the adhesive area is 151 mm). 2 The sample is then pressed at a pressure of at least 3 bar for at least 30 seconds to form a test specimen.

[0384] After pressing, the test specimens were conditioned at 23°C / 50% relative humidity (rh) for 72 hours. After storage, the bonded composite was clamped in a specimen holder such that the bond level was aligned. The test specimens were placed in the specimen holder with the disc (substrate (1)) facing down, and the bond strength was measured in the apparatus (Zwick). For this purpose, a steel piston with a diameter of 7 mm was moved through a circular opening in the substrate (2), and the force required to separate the circular substrate (1) from the square substrate (2) was measured. The measured force was divided by the bonded surface area as the output value, and the force was reported in MPa.

[0385] Three samples were tested for each product, and the average value was reported as an index of adhesive strength.

[0386] The following embodiments of the invention describe the production of tapes comprising at least one adhesive composition layer D, which are bonded between substrates and subsequently electrically debonded by applying voltage. The adhesive composition of layer D is, in each case, an adhesive composition capable of being cured by light at room temperature and is pressure-sensitive prior to activation.

[0387] Table 1: Chemicals Used

[0388] Transfer tape

[0389] Production of polymer P1

[0390] A 4 L reactor, typically used for free radical polymerization, was charged with 320 g of a mixture of 69 wt% phenoxyethyl acrylate and 31 wt% methyl methacrylate, along with 273 g of ethyl acetate / isopropanol (96 / 04). After bubbling with nitrogen under stirring for 45 minutes, the reactor was heated to 58 °C and 0.2 g of Vazo was added. ® 67 (2,2'-Azobis(2-methylbutyronitrile)). An additional 480 g of the above monomer mixture and 377 g of ethyl acetate were added continuously over 2 hours. The mixture was then heated to 65°C in an external heating bath and the reaction was carried out at this constant external temperature. 0.3 g of 2,2'-azobis(2-methylbutyronitrile) was added after 1 hour and after 1.5 hours of reaction, respectively. To reduce residual monomer, 0.12 g of di(4-tert-5-butylcyclohexyl) peroxide was added after 6 hours and after 7.5 hours, respectively. The mixture was diluted with 160 g of ethyl acetate after 2 hours and after 4 hours. The reaction was terminated after 24 hours and cooled to room temperature.

[0391] Production of poly(N-vinylcaprolactam) (P(NVC)) solution

[0392] 4.0 kg of N-vinylcaprolactam, 3.84 kg of acetone, and 0.16 kg of isopropanol were charged into a 10 L glass reactor typically used for free radical polymerization. The reactor was heated to a jacket temperature of 65 °C under stirring (70 rpm) and nitrogen bubbling. When the internal temperature reached 58 °C, 2.0 g of Vazo was added. ® 67. After stirring for another hour at a jacket temperature of 65°C, add an additional 2.0 g of Vazo. ® 67. After stirring for an additional 6 hours at a jacket temperature of 65°C, the stirrer speed was reduced to 35 rpm. The reaction time was 20 hours. The solution was then cooled to room temperature and diluted with acetone to a solids content of 40.0% by weight. The molar mass of the obtained poly(N-vinylcaprolactam) was determined by thermal field flow fractionation, as determination by GPC was not possible. Result: M N =74,000 g / mol, M W =116,500 g / mol. The figures in Table 2 refer to polymers as solids.

[0393] Production of reactive adhesive compositions

[0394] Aqueous photo-oxidation-reduction catalyst solution

[0395] Under yellow light, 5 g of tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate and 95 g of completely deionized water were weighed into a brown screw-cap flask. The screw-cap flask was sealed. The tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate was completely dissolved by rolling the screw-cap flask on a roller mixer for 8 hours.

[0396] Reactive adhesive compositions

[0397] The production of the base compositions for the reactive adhesive compositions was carried out in the laboratory according to the proportions shown in Table 2 below. The polymers produced in the solvent were mixed with additional raw materials, and then an aqueous photoredox catalyst solution was added by stirring. When commercial polymers were used, they were produced as a 40% solution in methyl ethyl ketone (MEK). However, the amount of MEK was not reported in Table 2.

[0398] Table 2

[0399] The adhesive compositions K1 and K2 were adjusted to a solid content of 34% using methyl ethyl ketone (MEK).

[0400] Production of reactive pressure-sensitive tape

[0401] To produce reactive adhesive composition layers, i.e., carrier-free transfer pressure-sensitive tapes, different reactive adhesive compositions were applied from solution to a conventional backing (silicone-coated polyester film) and dried using a laboratory coating machine. The adhesive composition layers were approximately 21 cm × 30 cm in size and had a thickness of 100 ± 5 μm after drying. In each case, drying was initially performed at room temperature for 15 minutes, followed by 15 minutes at 120°C in a laboratory drying oven. In each case, the dried adhesive composition layer was immediately laminated onto the open side with a second backing (silicone-coated polyester film with lower peel strength) immediately after drying.

[0402] The corresponding tapes are produced from adhesive compositions K1 and K2.

[0403] Reactive adhesive tapes ED1-ED7 that can be electrically delaminated

[0404] 7% BMIM-TFSI was stirred into the adhesive composition solution K1, and pressure-sensitive tape was produced as described above to obtain Example ED1.

[0405] K2 was mixed with the following ionic liquids (iF) in the proportions listed in Table 3 (in %), and the corresponding pressure-sensitive tapes were produced in the same manner to obtain Examples ED2 to ED7.

[0406] All reported ionic liquid proportions are based on 100 parts by weight of the corresponding solvent-free adhesive composition K1 or K2 in each case, i.e., based on 100 parts by weight of dry mass. Therefore, in Example ED2, 3 parts by weight of the ionic liquid EMIM-FSI were added to 100 parts by weight of the dry base composition K2.

[0407] Table 3

[0408] The adhesive strength of the comparative tape composed of K1 and K2 and the electrically debonding tapes ED1 to ED7 of the present invention were determined by the above method, wherein the samples were activated by irradiation during sample preparation, as specified in the method description of adhesive strength.

[0409] The results are also summarized in Table 4.

[0410] Additional samples of the listed tapes were also produced and subjected to an applied voltage of 12 V for 3 minutes before the adhesive strength was measured. The results are also summarized in Table 4.

[0411] Table 4

[0412] As demonstrated in the experiments on adhesive strength and debonding properties of embodiments ED1 to ED7 of the present invention, the application of voltage significantly reduces adhesive strength when an ionic liquid is present in the adhesive composition layer D. Therefore, the bonded substrates can be debonded from each other without applying significant force. Debonding is also achieved without residue.

[0413] List of reference numerals

[0414] 1. Adhesive composition layer D

[0415] 2. Conductive carrier layer T

[0416] 2a Free surface of conductive carrier layer T

[0417] 3 Second adhesive composition layer C

[0418] 3a Free surface of adhesive composition layer C

[0419] 4 First base A

[0420] 5 Second basement B

[0421] 6 Second conductive carrier layer T'

[0422] 6a Free surface of conductive carrier layer T'

[0423] 7 Third adhesive composition layer C'

Claims

1. A reactive adhesive tape comprising at least one layer D of a reactive curable adhesive composition containing a base composition, wherein the base composition comprises: a) One or more polymers, and b) One or more monomers and / or oligomers capable of free radical polymerization, and c) At least one initiator, and / or d) At least one redox catalyst, Furthermore, the adhesive composition layer D capable of reacting and curing further comprises: e) At least one electrolyte.

2. The reactive tape according to claim 1, characterized in that, The electrolyte in the adhesive composition layer D is selected from ionic liquids and metal salts, with ionic liquids being particularly preferred.

3. The reactive tape according to claim 2, characterized in that, The anions of the ionic liquid are selected from: Br - AlCl4 - Al2Cl7 - NO3 - BF4 - PF6 - CH3COO - CF3COO - CF3CO3 - CF3SO3 - (CF3SO2)2N - (CF3SO2)3C - AsF6 - SbF6 - CF3(CF2)3SO3 - (CF3CF2SO2)2N - CF3CF2CF2COO - (FSO2)2N - N(CN)2 - Particularly preferred is (CF3SO2)2N - (FSO2)2N - PF6 - and N(CN)2 - .

4. The reactive adhesive tape according to any one of the preceding claims, characterized in that, The cation of the ionic liquid is selected from imidazolium-based cations, pyridinium-based cations, pyrrolidine-based cations, ammonium-based cations, phosphonium-based cations, oxazolium-based cations, guanidineium-based cations, and thiazolium-based cations. Particularly preferred are cations based on imidazolium, cations based on pyridinium, and cations based on ammonium, with imidazolium-based cations and pyridinium-based cations being the most preferred.

5. The reactive adhesive tape according to any one of the preceding claims, characterized in that, The cations are selected from: 1-Ethyl-3-methylimidazolium and 1-Butyl-3-methylimidazolium.

6. The reactive adhesive tape according to any one of the preceding claims, characterized in that, The electrolyte of the adhesive composition layer D is selected from ionic liquids 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-TFSI), 1-butyl-3-methylimidazolium bis(fluorosulfonyl)imide (BMIM-FSI), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-FSI), and 1-ethyl-3-methylimidazolium dicyandiamide.

7. The reactive adhesive tape according to any one of the preceding claims, characterized in that, The polymer is selected from ethylene-vinyl acetate copolymer (EVA), poly(meth)acrylate, polyurethane (PU), polyvinyl acetate (PVA), polyvinyl acetal such as, in particular, polyvinyl butyral (PVB), polyester, and polymers containing monomers comprising N-vinyl compounds, wherein the polymer is particularly preferably selected from ethylene-vinyl acetate copolymer (EVA), poly(meth)acrylate, poly(N-vinylcaprolactam), poly(N-vinylpyrrolidone), and polyurethane (PU).

8. The reactive adhesive tape according to any one of the preceding claims, characterized in that, The monomers or oligomers that can undergo free radical polymerization have a boiling point of at least 30°C, preferably at least 60°C and particularly preferably at least 80°C at 1 mbar, or are in solid form at 23°C.

9. The reactive adhesive tape according to any one of claims 1 to 8, characterized in that, It is a transfer tape and consists of an adhesive composition layer D.

10. The reactive tape according to any one of claims 1 to 8, characterized in that, It further comprises at least one second adhesive composition layer C, wherein the second adhesive composition layer is preferably conductive and, more preferably, also a reactive curable adhesive composition layer.

11. The reactive adhesive tape according to any one of claims 1 to 8, characterized in that, It also includes at least the following layers: The second adhesive composition layer C is preferably also a reactive and curable adhesive composition layer; and At least one conductive carrier layer T is disposed between layers D and C.

12. The reactive tape according to any one of claims 1 to 11, characterized in that, The at least one reactive curable adhesive composition layer D is a photocurable adhesive composition layer, and contains c) at least one initiator and d) at least one redox catalyst, wherein the redox catalyst is a photoredox catalyst.

13. The reactive tape according to claim 12, characterized in that, The photo-oxidation-reduction catalyst contains ruthenium as a central atom and bipyridine or mono- or poly-substituted bipyridine derivatives as ligands, or iridium as a central atom and phenylpyridine or mono- or poly-substituted phenylpyridine derivatives as ligands.

14. A reactive tape system comprising at least one first reactive tape according to any one of claims 1 to 11 and a second reactive tape comprising at least one reactive curable adhesive composition layer, wherein the at least one reactive curable adhesive composition layer D of the first reactive tape comprises at least one initiator and preferably does not contain a redox catalyst, and the at least one reactive curable adhesive composition layer of the second reactive tape comprises at least one redox catalyst and preferably does not contain an initiator, wherein the second reactive tape is preferably also a tape according to any one of claims 1 to 11.

15. An bonded composite comprising at least the following layers: First basement A; and Second basement B; and The tape according to any one of claims 1 to 13 or the tape system according to claim 14 is disposed between substrate A and substrate B and bonds substrate A and B to each other.

16. A method for electrically debonding the composite according to claim 15, comprising at least the following method steps: i.) Apply a voltage at two different points on the composite, wherein the voltage is preferably 2 to 50 V.

17. Use of the tape according to any one of claims 1 to 13 or the tape system according to claim 14 for bonding components in electronic, optical or precision mechanical devices, automobiles, medical devices and dental devices.

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