Removable, optically clear adhesive tape

Abstract

The present invention relates to removable, optically clear adhesive tapes, a process for their production, their use and components produced with the adhesive tapes.

Description

[0001] The present invention relates to removable, optically clear adhesive tapes, a process for their production, their use and components produced with the adhesive tapes.

[0002] Removable adhesive tapes have been around for a long time and are primarily used for fastening light and medium-weight objects in homes, work areas and offices, where they are used as a replacement for traditional fastening materials such as nails and screws.

[0003] EP 1 418 212 describes a transparent pressure-sensitive adhesive strip comprising at least three layers which can be removed again by stretching essentially in the bond plane without leaving residues or being destroyed, wherein the two outer layers each consist of a transparent adhesive composition based on hydrogenated vinyl aromatic block copolymers and adhesive resins, at least one layer is present between the two outer layers which is composed of a transparent adhesive composition based on vinyl aromatic block copolymers and which has a higher elongation at break than the two outer layers.

[0004] EP 0 761 793 relates to the multiple use of an adhesive film laminate for bonds which can be removed again without residue by pulling on the laminate in the direction of the bonding plane, the laminate being one comprising a) an elastic carrier with a recovery capacity of at least 50%, and b) coated on at least one side with a solvent-based or hot-melt acrylate pressure-sensitive adhesive or dispersion acrylate pressure-sensitive adhesive.

[0005] US 2017 / 158919 provides a pressure-sensitive adhesive film for portable electronic devices, wherein the adhesive film has a shear bond strength of 0.5 MPa or more, a tear strength of 10 MPa or more and an elongation at break of 300% or more.

[0006] US 2017 / 0158918 discloses a pull-removable adhesive tape having a shear bond strength of 0.5 MPa or more, a tensile strength of 10 MPa or more, and an elongation at break of 300% or more.

[0007] While in the early days, the application of removable adhesive tapes was limited to simple fastenings, the technical fields in which they are used are now significantly more diverse, which also increases the demands placed on the adhesive tapes themselves. One application that has attracted particular attention in the electronics and automotive industries is the use of such adhesive tapes for bonding electronic devices, especially displays. Accordingly, the range of properties of the adhesive tapes is no longer limited to their mechanical properties, but also includes optical properties such as transparency. For example, highly transparent and UV-resistant products with low haze are required for the lamination of displays and touchscreens.

[0008] Furthermore, during display manufacturing, the optical bonding of the display panel or touch layer and the cover glass with a material with as similar a refractive index as possible is necessary to avoid reflections and thus maximize the light output and brightness of the display. Optically clear adhesives (OCA) are used in this process, which can be liquid (liquid OCA - LOCA) or as transfer adhesive (OCA). When used for large, curved, and complex displays, these substrates are very expensive and fragile.

[0009] WO 2012 / 087804 discloses an optical interconnect layer comprising an optical film and a liquid optically clear adhesive (LOCA) positioned adjacent to the optical film, wherein the optical interconnect layer has a light transmittance of at least 75%. The interconnect layer is said to be removable by stretching.

[0010] However, the use of LOCA has disadvantages. For example, curing can cause stress in the bond, which in turn can lead to delamination or the so-called mura effect (a shadow-like impairment of the display). Furthermore, the curing process of a LOCA is time-consuming, which in turn has a negative impact on process efficiency.

[0011] WO 2009 / 089137 relates to a stretch-removable adhesive tape having a pressure-sensitive adhesive comprising a silicone polymer and a sticky tab.

[0012] The disadvantage of silicone-based OCAs is their lower refractive index compared to acrylates, resulting in lower light output (increased reflection). Furthermore, silicone-based OCAs are weaker in bond strength and durability compared to acrylate-based OCAs.

[0013] Although approaches to optically clear, removable adhesive tapes already exist, these often exhibit the disadvantages described above. This problem is particularly pronounced when bonding larger displays, such as those used in the automotive industry.

[0014] In particular, optical defects in the adhesive bond, such as air bubbles or detachments after the curing process, repeatedly occur during bonding. This requires the expensive components to either be disposed of or laboriously separated manually. For the latter, methods using a cutting wire are used, or attempts are made to mechanically separate the adhesive bond after freezing at very low temperatures (-80 °C to -140 °C). Both methods carry a high risk of destroying the display components. Therefore, it is desirable to have a simple mechanism for separating already joined display components during production.

[0015] It is therefore the object of the present invention to provide an optically clear adhesive tape that can be removed from larger surfaces without leaving residues or being damaged, in order to enable simple correction of faulty lamination, for example of displays.

[0016] The object is achieved by an adhesive tape according to claim 1. Preferred embodiments of the adhesive tape according to the invention are set out in the dependent claims.

[0017] A first object of the present invention is therefore a removable, optically clear adhesive tape comprising: • an elastic support, the support having an elongation of at least 300% and a maximum tensile force at 200% elongation of 20 MPa, determined in accordance with DIN 53504; • an optically clear acrylate-based pressure-sensitive adhesive applied to both sides of the carrier, the pressure-sensitive adhesive having a microshear displacement of less than 2 mm, determined according to the “microshear displacement” method at a load of 200 g for 15 minutes, a layer thickness of 100 µm and a temperature of 40 °C.

[0018] Within the scope of the present invention, it has surprisingly been shown that, in particular, the combination of the physical properties of the carrier and the microshear path of the pressure-sensitive adhesive provides an adhesive tape with the aforementioned property profile, which not only forms a stable bond but can also be easily removed from the substrate without damaging it, even when lamination of larger surfaces is involved. Thus, defects that arise during lamination, such as air pockets, can be easily repaired without having to discard the display.

[0019] Unless otherwise stated, all quantities are in % by weight.

[0020] The adhesive tape according to the invention is particularly characterized by the microshear displacement of its pressure-sensitive adhesive. In a preferred embodiment, this displacement is less than 1 mm, particularly preferably less than 0.5 mm.

[0021] To determine the microshear displacement, the adhesive can be applied to a dimensionally stable carrier of a defined width and bonded with the free adhesive side to a steel test substrate. A defined weight is suspended from the carrier below the bond, and the vertical deflection of the test specimen is recorded over a certain period of time as the microshear displacement. A detailed description of the determination method can be found in the "Test Methods" section of the present application and is further described in EP 1 674 544, paragraph

[0048] ff.

[0022] To enable the adhesive tape to be removed by pulling, the carrier used according to the invention preferably has an elongation of at least 300%, preferably more than 500%, and a maximum tensile force at 200% elongation of 20 MPa. In a particularly preferred embodiment, the carrier has a maximum tensile force at 200% elongation of less than 10 MPa, particularly preferably less than 5 MPa. A low tensile force at 200% elongation ensures that the force F required for pulling out Stripp If possible, the stripping force should not exceed 15 N / cm, as otherwise the forces acting on the sensitive display components could become excessive and damage them. The stripping force can be determined as described in the "Test Methods" section.

[0023] The carrier used in the adhesive tape according to the invention can be made from a variety of materials. In a preferred embodiment, the carrier material is selected from the group consisting of styrene block copolymers, natural rubber, polyisoprene, polybutadiene, polychloroprene rubber, butyl rubber, EPDM rubber, ethylene-propylene copolymers, polyurethanes, vinyl copolymers, ethylene-vinyl acetate copolymers, vinyl chloride-acrylate copolymers, polyetheresters, polyetheramides, polyesteramides, polyetheramide block copolymers, polycarbonate-polyester copolymers, ethylene-acrylate copolymers-ABS, copolymers, and mixtures and blends thereof.

[0024] Polyurethane backings have proven particularly advantageous, with thermoplastic polyurethanes (TPU) and dispersion polyurethanes (PUD), aromatic polyurethanes, aliphatic polyurethanes, polyester-polyol-based polyurethanes, polyether-polyol-based polyurethanes, polycarbonate-based polyurethanes, urethane-based (meth)acrylates, as well as hybrids and mixtures thereof being particularly preferred. The polyurethane can be crosslinked or uncrosslinked.

[0025] Preferably, optically clear supports are used, which preferably have an optical transparency of at least 95%, determined by transmission measurement.

[0026] The adhesive tape according to the invention uses an optically clear pressure-sensitive adhesive. For the purposes of the present invention, an optically clear pressure-sensitive adhesive is understood to mean a pressure-sensitive adhesive that has an optical transparency of at least 95%, determined by transmission measurement.

[0027] An acrylate-based pressure-sensitive adhesive is used as the adhesive component in the adhesive tape according to the invention. This is preferably selected from the group consisting of solvent-containing and solvent-free acrylate adhesives, in particular copolymers based on acrylic acid / methacrylic acid and their esters with C1 to C25 atoms, maleic, fumaric, and itaconic acid and their esters, substituted (meth)acrylamides, other vinyl compounds such as vinyl esters, vinyl acetate, vinyl alcohol, and / or their esters; compounds of acrylate copolymers and resins; and compounds of various acrylate copolymers.

[0028] According to the invention, copolymers of acrylic acid and non-acrylate monomers can be used. It has proven advantageous to limit the content of free acrylic acid in the pressure-sensitive adhesive to avoid damage to the display caused by the acid. Therefore, an embodiment in which the pressure-sensitive adhesive is free of free acrylic acid is preferred. In this regard, a proportion of less than 5 ppm, particularly preferably less than 1 ppm, and especially less than 0.1 ppm is preferred.

[0029] The pressure-sensitive adhesive used in the adhesive tape of the invention can be selected and adapted depending on the desired application. Thus, monomers with a glass transition temperature below 0°C are particularly preferred as the basis of the pressure-sensitive adhesive, while for other applications, monomers with a glass transition temperature above 0°C are preferred. In yet other applications, the use of hydroxy-containing monomers is recommended. Furthermore, mixtures of these monomers can be used to obtain the pressure-sensitive adhesive.

[0030] To achieve good adhesive properties, such as good wetting of the substrates and flow of the adhesive, enclosing edges created by black prints applied to the edge of the display glass (black frame of the display), and a high suitability of the adhesive for flexible, foldable, and rollable displays, the pressure-sensitive adhesive is preferably obtained from a mixture of monomers that, as homopolymers, have a glass transition temperature of a maximum of 0 °C, whereby the glass transition temperature can be determined by DSC. The lower this specific glass transition temperature, the greater the positive effect on the above-mentioned adhesive properties.From the group of monomers with a maximum glass transition temperature of 0 °C, 2-ethylhexyl acrylate, n-butyl acrylate, propylheptyl acrylate, lauryl acrylate, iso-decyl acrylate, iso-octyl acrylate, n-octyl acrylate, stearyl acrylate, iso-stearyl acrylate, iso-C17 acrylate, ethylene diglycol acrylate, 2-ethylhexyl diglycol acrylate and 2-(2-ethoxyethoxy)ethyl acrylate as well as mixtures are particularly preferred.

[0031] In addition, for a particularly advantageous microshear path and the corresponding suitability of the adhesive for re-extraction from a laminated display, the use of monomers that, as homopolymers, have a glass transition temperature of at least 0 °C is advantageous. The higher this specific glass transition temperature, the stronger the positive effect on the mechanical properties according to the invention. From this group of monomers, dihydrodicyclopentadienyl acrylates, isobornyl (meth)acrylate, methyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, stearyl methacrylate, tert-butyl (meth)acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl (meth)acrylate, ethyl methacrylate, N-vinylpyrrolidone, n-vinylcaprolactam and dimethylacrylamide, diethylacrylamide, 4-acryloylmorpholine, phenoxybenzyl (meth)acrylate and mixtures are particularly preferred.

[0032] For the production of optically transparent adhesive tapes with OCA requirements, it can be advantageous to use hydroxy-containing monomers. On the one hand, this increases adhesion to the mostly polar substrates, such as glass, polycarbonate (PC), polymethyl methacrylate (PMMA), or polarizers. On the other hand, increasing the polarity of the OCA allows for better absorption of penetrating moisture at high temperatures and prevents clouding of the OCA. Preferred monomers include 2-hydroxyethyl (meth)acrylates, 2-hydroxypropyl (meth)acrylates, 3-hydroxypropyl (meth)acrylates, 2-hydroxybutyl (meth)acrylates, 4-hydroxybutyl (meth)acrylates, 6-hydroxyhexyl (meth)acrylates, 1,4-Cyclohexanedimethanol mono(meth)acrylates, 1-glycerol(meth)acrylates, 2-hydroxyethyl-(meth)acrylamides, N-hydroxypropyl(meth)acrylamides, vinyl alcohol and allyl alcohol and mixtures thereof.

[0033] In order to achieve an advantageous combination of the properties of the adhesive, appropriate monomer mixtures can be used.

[0034] The pressure-sensitive adhesive is preferably obtained by polymerizing a corresponding monomer mixture. The polymerization can be carried out by conventional methods, in particular by conventional radical polymerizations or controlled radical polymerizations. The polymers or oligomers can be produced by copolymerizing the monomer components using conventional polymerization initiators and, if appropriate, regulators. Polymerization can be carried out at conventional temperatures, for example, in bulk or in solution.

[0035] Preference is given to polymerization in solvents, particularly preferably in solvents having a boiling point in the range from 50 to 150 °C, particularly preferably in the range from 60 to 120 °C, using the usual amounts of polymerization initiators, the polymerization initiators generally being added to the monomer composition in a proportion of about 0.01 to 5% by weight, in particular from 0.05 to 2% by weight, based on the mass of the monomer composition.

[0036] Suitable polymerization initiators are, for example, radical sources such as peroxides, hydroperoxides and azo compounds, e.g. dibenzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide, di-t-butyl peroxide, cyclohexylsulfonyl acetyl peroxide, diisopropyl percarbonate, t-butyl peroctoate or benzpinacol.

[0037] Particularly preferred radical initiators are 2,2'-azobis(2-methylbutyronitrile), which is available, for example, under the trade name Vazo67 from Nouryon, or 2,2-azobis(2,4-dimethylvaleronitrile), which is available, for example, under the trade name Vazo52 from Nouryon. The temperature of the reaction mixture is preferably less than 70°C. The lower the polymerization temperature, the better the resulting polymer performs in terms of microshear and thus in its suitability for adhesive tape removal.

[0038] Suitable solvents are, in particular, alcohols such as methanol, ethanol, n- and isopropanol, n- and isobutanol, preferably isopropanol and / or isobutanol, as well as hydrocarbons such as toluene and, in particular, gasolines with a boiling point in the range of 60 to 120 °C. Ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and esters, such as ethyl acetate, as well as mixtures of these solvents, are particularly suitable. One function of solvents is to regulate the polymerization, which prevents the polymerization from leading to high molecular weights and ultimately to gelling. Some solvents have a stronger regulating effect than others, which particularly effectively prevents the risk of gelling. The use of the alcohols described has a strong regulating effect, which is why a maximum of 5 wt.% is preferably used in the solvent mixture.Ketones, as well as toluene, also have a regulating effect, albeit less strongly, which is why a maximum concentration of 40 wt.% is preferred. Excessive regulation of the polymerization, in turn, leads to an increase in the microshear path, making such copolymers unsuitable for an embodiment of the pressure-sensitive adhesive according to the invention.

[0039] At the start of polymerization, monomer concentrations of preferably 35% to 55% by weight, particularly preferably 40% to 50% by weight, are set. A monomer concentration that is too low has the same effect as an overly strong control, reducing the microshear displacement of the copolymer. A monomer concentration that is too high, in turn, increases the risk of gelling.

[0040] To improve the properties of the pressure-sensitive adhesive used in the adhesive tape of the invention, the pressure-sensitive adhesive can be crosslinked. Crosslinking can be carried out using at least one crosslinker, which is preferably selected from the group consisting of isocyanates, in particular selected from the group consisting of aliphatic polyisocyanates, silane isocyanates, acrylate isocyanates, and poly(propylene glycol), 2,4-tolylene diisocyanate. Polyfunctional epoxy crosslinkers such as polyglycidylamine are also suitable crosslinking reagents.

[0041] Suitable aliphatic isocyanates include, in particular, hexamethylene diisocyanate (HDI), 1,6-hexylene diisocyanate, isophorone diisocyanate (IPDI), 5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane, and trimethyl diisocyanate (TMDI). A suitable aliphatic polyisocyanate is available, for example, under the trade name Desmodur. ®N75 BA from Covestro AG. A suitable silane isocyanate is, for example, 3-isocyanatopropyltrimethoxysilane, which is sold under the trade name VESTANAT ® EP*-IPMS from Evonik Operations. A suitable acrylate isocyanate is available, for example, under the trade name VESTANAT ® EP*-DC 1241 from Evonik Operations. The adhesive preferably contains 0.02 to 0.5 wt. %, preferably 0.05 to 0.3 wt. %, particularly preferably 0.1 to 0.2 wt. %, of crosslinkers in the uncrosslinked state.

[0042] Too little crosslinking agent can adversely affect the microshear travel and, consequently, the suitability of the adhesive according to the invention. The degree of crosslinking is reflected in the microshear travel of the pressure-sensitive adhesive. The lower the degree of crosslinking, the longer the microshear travel.

[0043] The pressure-sensitive adhesive used can also be post-crosslinkable by using crosslinkable, reactive monomers, so-called multifunctional monomers. In such an embodiment of the invention, the adhesive is post-crosslinkable by means of multifunctional monomers and with the aid of a photoinitiator, wherein the adhesive contains the corresponding multifunctional monomers as a component for this purpose. The multifunctional monomers are preferably selected from the group consisting of difunctional (meth)acrylates, such as 1,10-decanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, tricyclodecanedimethylold di(meth)acrylate, (poly)ethyleneglycol di(meth)acrylate, (poly)propyleneglycol di(meth)acrylate, neopentylglycol di(meth)acrylate and pentaerythritol di(meth)acrylates as well as trifunctional or higher-functional (meth)acrylates such asPentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl (meth)acrylates, vinyl (meth)acrylates, divinylbenzene, epoxy acrylates, polyester acrylates, urethane acrylates, and also consists of the group of silanes and other related building blocks. The silanes can have various functional structures. The silanes can have only one alkoxy substitution. Alternatively, the silanes can have both an alkyl and an alkoxy substitution at the silicon atom.Examples of these silanes include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyl triethoxysilane, p-styryltrimethoxysilane, 3-metharyloxpropyl methyldimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyldiethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, and other related building blocks. The multifunctional monomers can be used individually or in combination with two or more monomers. This leads to advantages in the adhesive's adhesive properties, such as increased bond strength. However, the use of multifunctional monomers can have a negative impact on the inventive properties and the microshear path.

[0044] As can be seen from the possibilities outlined above, a number of alternatives are available to the skilled person for obtaining a pressure-sensitive adhesive usable according to the invention with a corresponding microshear path. For example, instead of using multifunctional acrylates or a crosslinker, a lower polymerization temperature and / or the proportion of monomers whose homopolymers have a glass transition temperature above 0 °C can be used to obtain pressure-sensitive adhesives with a microshear path as claimed according to the invention.

[0045] The pressure-sensitive adhesive used in the adhesive tape according to the invention is particularly preferably obtained by solvent-free polymerization using UV syrup technology, as this method allows particularly cohesive pressure-sensitive adhesives to be obtained. First, a prepolymer is prepared from a monomer mixture and a suitable photoinitiator (e.g., Irgacure 651) (5 to 10% conversion). The final formulation is then adjusted, optionally using additional monomers and / or additional photoinitiators, and coated between two siliconized PET films. The final curing takes place under UV light, preferably at a radiation dose of up to 10 J / cm 2. Additional crosslinking can also be achieved using di- and multifunctional acrylates such as hexanediol diacrylate or polyurethane acrylate-based crosslinkers (e.g., Miramer PU2562NT from Miwon), whereby care must be taken to ensure that free acrylic acid is not present. Suitable photoinitiators include (hydroxycyclohexyl)(phenyl)ketone (Irgacure 184), 2,2-dimethoxy-1,2-diphenylethan-1-one (Irgacure 651), 2,4,6-trimethylbenzoylphenylphosphinic acid ethyl ester (TPO-L), 2,4,6-trimethylphenyl-diphenyl)phosphine oxide (TPO), or phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819).

[0046] The adhesive tape according to the invention is developed especially for the production of optical components such as displays. In this field, high demands are placed not only on the adhesive properties of the adhesive tapes, but also on their optical properties. Within the scope of the present invention, it has surprisingly been shown that it is possible to use the adhesive tape according to the invention to meet the high quality requirements set by the automotive industry in this regard. Therefore, in a preferred embodiment, the adhesive tape according to the invention has at least one, preferably several, in particular all, of the following properties: • a transmission of at least 95%, determined according to the “Transmission Method” • a b-value of less than 1.5, determined according to the “b-value method” • a haze of less than 1.5, determined according to the “Haze Method” • a refractive index nD of 1.45 to 1.53, determined according to the “Refractive Index Method”.

[0047] The adhesive tape according to the invention is coated on both sides with a pressure-sensitive adhesive. Depending on the application, it may be advantageous to use different pressure-sensitive adhesives. Therefore, an embodiment in which the pressure-sensitive adhesives are the same or different is preferred.

[0048] In a preferred embodiment, the adhesive tape according to the invention has a thickness of 100 to 500 µm.

[0049] In addition to its optical properties, the adhesive tape according to the invention is characterized by its removability, which is achieved, among other things, by the adhesive tape's elongation at break. This is preferably between 300 and 800%, determined according to DIN 53504.

[0050] The present invention further provides a process for producing the adhesive tape of the invention. For this purpose, a composite is formed from the carrier and the pressure-sensitive adhesive, with the carrier being arranged between two pressure-sensitive adhesive layers. For this purpose, the carrier can be coated or laminated on both sides with the pressure-sensitive adhesive. Furthermore, the carrier can be subjected to corona pretreatment, for example, in air at 120 W min / m 2 This strengthens the bond between the backing and the pressure-sensitive adhesive, preventing delamination of the pressure-sensitive adhesive should the tape need to be removed.

[0051] A number of different pressure-sensitive adhesives can be used to produce the adhesive tape according to the invention, the process according to the invention being adapted accordingly in each case.

[0052] In a preferred embodiment, the adhesive tape according to the invention is produced by the pressure-sensitive adhesive comprising a mixture of monomers having a glass transition temperature of less than, equal to or greater than 0 °C and 5 to 30 wt. % of hydroxy-containing acrylates, based on the monomer mixture, preferably at a temperature of less than 70 °C, a monomer content at the start of polymerization of 35 to 55 wt. % and • in ethyl acetate with a regulating solvent component, preferably 20 to 40 wt.% MEK, • using an azo-based radical initiator which has a half-life of 10 h and a maximum temperature of 80 °C, polymerized, • with more than 0.02 wt.% isocyanate-based crosslinker based on the solid polymer content • and optionally with further reactive monomers in a total proportion of maximum 10 wt.% based on the solid polymer content mixed, coated on a siliconized liner film, dried and then bonded to the carrier.

[0053] In an alternatively preferred embodiment, the adhesive tape according to the invention is produced by a pressure-sensitive adhesive comprising 5 to 30% by weight of hydroxy-containing acrylates and at least 50% by weight of monomers, the homopolymer of which has a glass transition temperature of at least 0°C, based on the monomer mixture, preferably at a temperature of less than 70°C, a monomer content at the start of polymerization of 35 to 55% by weight and • in ethyl acetate with a regulating solvent component, preferably 20 to 40 wt.% MEK, • using an azo-based radical initiator which has a half-life of 10 h and a maximum temperature of 80 °C, polymerized, • and optionally with further reactive monomers in a total proportion of maximum 10 wt.% based on the solid polymer content • and optionally mixed with more than 0.02 wt.% isocyanate-based crosslinker based on the solid polymer content, coated on a siliconized liner film, dried and then a composite is created with the carrier.

[0054] In an alternatively preferred embodiment, the adhesive tape according to the invention is produced by mixing a pressure-sensitive adhesive comprising at least 5% by weight of hydroxy-containing acrylates, a proportion of photoinitiator of less than 0.5% by weight and either • more than 10% monomers whose homopolymers have a glass transition greater than 0 °C, or • using a crosslinking component with a content of at least 0.01 wt.%, preferably at least 0.03 wt.%, particularly preferably at least 0.05 wt.%, based on the solid polymer content, or • more than 10 wt.% monomers whose homopolymers have a glass transition of greater than 0 °C using a crosslinking component with a content of at least 0.01 wt.%, preferably at least 0.03 wt.%, particularly preferably at least 0.05 wt.%, based on the solid polymer content, coated between two siliconized liners via a UV syrup process, under UV light, preferably with a UV dose of 3000 mJ / cm 2 or less, and then a bond is created with the carrier.

[0055] The present invention further provides an optical display comprising the adhesive tape according to the invention. The display according to the invention can be used, for example, in electronic devices such as mobile phones, tablets, laptops, and the like.

[0056] A further object of the present invention is the use of the adhesive tape according to the invention for producing optical components, in particular displays.

[0057] The invention is explained in more detail with reference to the following examples, which, however, are in no way to be understood as a limitation of the inventive concept. i) Test methods

[0058] Unless otherwise stated, all measurements were performed at 23 °C and 50% relative humidity. thickness

[0059] The thickness of an adhesive layer can be determined by determining the thickness of a section of such an adhesive layer applied to a liner, defined in terms of its length and width, minus the (known or separately determinable) thickness of a section of the same dimensions of the liner used. The thickness of the adhesive layer can be determined using commercially available thickness gauges (touch-type thickness gauges) with an accuracy of less than 1 µm. If thickness variations are detected, the average value of measurements taken at at least three representative locations is given, thus, in particular, excluding measurements taken at creases, folds, spots, and the like. Redetachment by stretching

[0060] In the removability test, the double-sided adhesive tape to be tested is bonded between two test panels made of polycarbonate and glass.

[0061] Test specimens 20 mm wide are cut from the adhesive tape to be tested. These test specimens are bonded to the first glass test plate after uncovering the first siliconized PET film over a length of 70 mm. After uncovering the second siliconized PET film, the free adhesive is covered on both sides with 36 µm PET. The second PC test plate is cleaned with isopropanol and preconditioned for 1 to a maximum of 10 minutes at 23 °C and 50% relative humidity, and then bonded to the opposite side of the bonded strip (i.e., test specimen) in such a way that the PC plate protrudes beyond the glass plate. The back of the composite is rolled over the steel plate 10 times using a 4 kg roller (five times back and forth).After at least 24 hours of application at 23 °C and 50% relative humidity, the strips are stripped from the adhesive joint at the grip using a tensile testing machine (Zwick) at a constant speed of 800 mm / min at an angle of 0°. The specimen is fixed with an angle-adjustable adapter, and the grip is clamped vertically in the center of the clamping jaws.

[0062] It is measured at an angle of 0° and during this time the force required to continuously remove / strip the sample is recorded by the tensile testing machine - the so-called stripping force F Stripp The measurement is complete when the sample has been completely removed from between the two test plates or the sample has cracked during the measurement. At least two measurements are performed per sample. The test environment is 23 °C and 50% relative humidity.

[0063] Indication of results: FStripp [N / cm] - force required to strip the test specimen from the adhesive joint at an angle of 0° (stripping force) Tensile test using a tensile testing machine, Zwick

[0064] From the sample to be tested (adhesive tape, i.e., a backing preferably coated with adhesive on both sides, or just a blank backing), 15 mm wide strips with a length of approximately 150 mm are cut lengthwise using a strip cutter or razor blade knife. The sample, preconditioned for 24 hours in the test environment, is clamped vertically in the center of the clamping jaws with a clamping length of 10 mm and stretched at a speed of 800 mm / min until it tears. The tear should occur approximately in the center of the strip. If the tear occurs near the jaws (closer than 1 cm), the value is discarded and a different strip is tested. Five measurements are performed for each sample variant. The test environment is 23 °C and 50% relative humidity. The measurements are carried out in accordance with EN ISO 527.

[0065] Indication of results: F x% [N / cm], [N / mm 2 ] - Force at x % elongation F Bruch [N / cm], [N / mm2 ] - Force at tear / break of the sample (ie tear strength) RD [%] - Elongation at break, ie percentage elongation at tear / break of the sample Modulus at x% elongation, elongation at break

[0066] The modulus at x% elongation or the elongation at break of a sample are determined according to DIN 53504. Microshear path

[0067] This test is used for the accelerated testing of the shear strength of adhesive tapes under temperature stress. Sample preparation for the microshear path

[0068] The pressure-sensitive adhesive sample, which is doubly covered in siliconized PET film, is first covered on one side and laminated with an etched PET film (e.g., 50 µm). A cut-out adhesive strip (approx. 50 mm long, 10 mm wide) is then adhered to a steel plate cleaned with acetone, such that the steel plate extends beyond the adhesive tape on the right and left, and the adhesive strip extends 2 mm beyond the test plate at the upper edge. The adhesive surface of the sample (height × width) is 13 mm × 10 mm. The bonding area is then rolled over six times with a 2 kg steel roller at a speed of 10 m / min. The adhesive tape is reinforced flush with a sturdy adhesive strip, which serves as a carrier for the displacement sensor. The sample is suspended vertically using the test plate. Microshear displacement measurement

[0069] The test specimen to be measured is loaded with a weight of 200 g at its lower end. The test temperature is 40°C, and the test duration is 15 minutes. Glass transition temperature T g

[0070] The glass transition temperature of polymers can be determined using differential scanning calorimeters (DSC). Approximately 5 mg of the untreated polymer sample is weighed into an aluminum crucible (volume 25 µl) and sealed with a perforated lid. A Netzsch DSC 204 F1 is used for the measurement, operated under nitrogen for inerting. The sample is first cooled to -150°C, then heated to +150°C at a heating rate of 10 K / min and cooled back to -150°C. The subsequent second heating curve is run at a rate of 10 K / min, and the change in heat capacity is recorded. Glass transitions are marked as steps in the thermogram. The glass transition temperature is determined as follows: A tangent is drawn to the baseline of the thermogram before each step.In the step region, a best-fit line is placed parallel to the ordinate so that it intersects the two tangents, creating two regions of equal content (between each tangent, the best-fit line, and the measured curve). The intersection point of the best-fit line positioned in this way with the measured curve yields the glass transition temperature. transmission

[0071] The transmittance of the adhesive tape is determined according to ASTM D1003-13 (Procedure A (BYK Gardner Haze Gard Plus), standard illuminant D65). A correction for interfacial reflection losses is made. The transmittance of other layers is determined analogously and refers to the actual thickness of the layer. Haze

[0072] The haze of the entire assembly is determined as described in ASTM D1003-13 using a BYK Gardner Haze Gard Plus. The haze value describes the proportion of transmitted light that is scattered forward at a large angle by the sample being irradiated. Thus, the haze value quantifies material defects in the surface or structure that impair clear visibility. The standard requires the measurement of four transmission measurements. The light transmittance is calculated for each transmission measurement. The four transmittances are added together to determine the percentage haze value. The haze of other coatings is determined analogously and refers to the actual thickness of the coating. b-value

[0073] The b-value is a measure of discoloration on a yellow-blue color scale and, together with the L-value (brightness) and the a-value (red-green color scale), provides an objective determination of color perception. The so-called Lab values are determined using the Spectro-Guide-Sphere-Gloss device from BYK Gardner in accordance with ASTM D2244-096 and DIN 6174. First, a triple background measurement is performed on a known reference substrate. The adhesive tape is then measured on this reference substrate, also at three different locations. To determine the b-value, the average of the three individual values is calculated and the average of the reference value is subtracted. refractive index

[0074] An Abbemat 350 refractometer (Anton Parr) is used to determine the refractive index. First, a test measurement is performed against air or water to verify functionality. The adhesive tape or individual components are then applied to the measuring window, and the measurement is started. The measurement is performed at 20 °C. ii) ExamplesSolvent-based manufacturing processesExample A1

[0075] A reactor conventional for radical polymerizations is charged with 140 g of 2-ethylhexyl acrylate, 180 g of isobornyl acrylate, 80 g of 4-hydroxybutyl acrylate, and 400 g of ethyl acetate / 2-butanone (70 / 30). After 45 minutes of nitrogen gas flow with stirring, the reactor is heated to 70°C, and 0.27 g of Vazo52 is added. The external heating bath is then controlled to maintain a constant temperature of 40°C. After 2 h, another 0.27 g of Vazo52 is added, and after 4.5 h and 6 h, the mixture is diluted with 80 g of ethyl acetate / 2-butanone mixture. After 7 h, the reaction is reinitiated with 0.21 g of Vazo67, and the reaction temperature is raised to 80°C. After 18 h of reaction time, the polymerization is terminated and cooled to room temperature. The polymer solution is then heated to approx.The film is diluted to 30% solids with ethyl acetate and coated onto a siliconized PET liner using a doctor blade to form a 100 µm thick adhesive film after evaporation of the solvent for 30 minutes. This film is then oven-dried for 15 minutes at 120 °C, covered with a second siliconized PET liner, and stored at room temperature for 6 days until final crosslinking is achieved. Example A2

[0076] A reactor conventional for radical polymerizations is charged with 160 g of n-butyl acrylate, 80 g of lauryl acrylate, 48 g of 4-hydroxybutyl acrylate, 112 g of 2-propylheptyl acrylate, and 489 g of ethyl acetate / 2-butanone (70 / 30). After 45 minutes of nitrogen gas flow while stirring, the reactor is heated to 70°C, and 0.31 g of Vazo52 is added. The external heating bath is then controlled to maintain a constant temperature of 40°C. After 1 h, another 0.31 g of Vazo52 is added, and after 2.5 h, 3 h, 3.5 h, 4.75 h, and 6.5 h, the reaction mixture is diluted with 80 g of the ethyl acetate / 2-butanone mixture. After 10 h, the reaction mixture is reinitiated with 0.24 g of Vazo67, and the reaction temperature is increased to 80 °C. After 18 h of reaction time, the polymerization is terminated and cooled to room temperature. The polymer solution is then cooled to approximatelyThe film is diluted to 30% solids with ethyl acetate and coated onto a siliconized PET liner using a doctor blade to form a 100 µm thick adhesive film after evaporation of the solvent for 30 minutes. This film is then oven-dried for 15 minutes at 120 °C, covered with a second siliconized PET liner, and stored at room temperature for 6 days until final crosslinking is achieved. Example A3

[0077] A reactor conventional for radical polymerizations is charged with 108 g of n-butyl acrylate, 100 g of methyl acrylate, 80 g of 4-hydroxybutyl acrylate, 112 g of tert-butyl acrylate, and 600 g of ethyl acetate / 2-butanone (70 / 30). After 45 minutes of nitrogen gas flow with stirring, the reactor is heated to 70 °C, and 0.62 g of Vazo67 is added. The external heating bath is then controlled to maintain a constant temperature of 65 °C. After 3.65 h and 6.75 h, the reaction mixture is diluted with 80 g of ethyl acetate / 2-butanone mixture. After 10 h, the reaction temperature is increased to 80 °C. After 18 h of reaction time, the polymerization is terminated, and the reaction mixture is cooled to room temperature. The polymer solution is then mixed with 6% of the polymer solids content of ethoxylated trimethylolpropane triacrylate, 2% vinyltrimethoxysilane and 2% TPO-L to approx.The film is diluted to 30% solids with ethyl acetate and coated onto a siliconized PET liner using a doctor blade to form a 100 µm thick adhesive film after evaporation of the solvent for 30 minutes. This film is then oven-dried for 15 minutes at 120 °C, covered with a second siliconized PET liner, and stored at room temperature for 6 days until final crosslinking is achieved. Comparison example V1

[0078] A reactor conventional for radical polymerizations is charged with 228 g of n-butyl acrylate, 80 g of methyl acrylate, 40 g of 4-hydroxybutyl acrylate, 52 g of tert-butyl acrylate, and 600 g of ethyl acetate / 2-butanone (70 / 30). After 45 minutes of nitrogen gas flow with stirring, the reactor is heated to 70 °C, and 0.62 g of Vazo67 is added. The external heating bath is then controlled to keep the reaction mixture constant at 65 °C. After 10 h, the reaction temperature is increased to 80 °C. After 18 h of reaction time, the polymerization is terminated and cooled to room temperature. The polymer solution is then admixed with 6%, based on the solids content of the polymer, of ethoxylated trimethylolpropane triacrylate, 2% vinyltrimethoxysilane, and 2% TPO-L, and the mixture is diluted to approximately 10 °C.The film is diluted to 30% solids with ethyl acetate and coated onto a siliconized PET liner using a doctor blade to form a 100 µm thick adhesive film after evaporation of the solvent for 30 minutes. This film is then oven-dried for 15 minutes at 120 °C, covered with a second siliconized PET liner, and stored at room temperature for 6 days until final crosslinking is achieved. UV syrup technologyExample A4

[0079] A reactor conventional for radical polymerizations is charged with 160 g of 2-ethylhexyl acrylate, 120 g of 4-hydroxybutyl acrylate, and 120 g of tert-butyl acrylate, as well as the photoinitiator Irgacure 651 at a concentration of 0.01 wt.%. After passing nitrogen gas through the reactor for 45 minutes while stirring, the reactor is sufficiently purged of oxygen. Subsequently, a (UV) LED lamp with an intensity of 3000 [mJ / cm 2] the reaction is started for 10 min until a monomer-polymer mixture with a defined viscosity is obtained.

[0080] The prepolymer is then blended with photoinitiator Irgacure 184 (0.2 wt.%) and crosslinker (0.1 wt.% HDDA), and a vacuum pump is used to create a vacuum to remove any bubbles from the mixture. The blend is then coated with a thickness of 100 µm between two siliconized PET films (50 µm each). Further conversion to 100% polymer is initiated by irradiation with a Heraeus UV-LED lamp (wavelength 365 nm) with a UV dose of 3000 mJ / cm³. 2 . Example A5

[0081] A reactor conventional for radical polymerizations is charged with 320 g of 2-ethylhexyl acrylate, 60 g of 4-hydroxybutyl acrylate, and 20 g of tert-butyl acrylate, as well as the photoinitiator Irgacure 651 at a concentration of 0.01 wt.%. After passing nitrogen gas through the reactor for 45 minutes while stirring, the reactor is sufficiently purged of oxygen. Subsequently, the reactor is illuminated with a (UV) LED lamp with an intensity of 3000 [mJ / cm 2 ] for 10 min, the reaction is started until a monomer-polymer mixture with a defined viscosity is obtained.

[0082] The prepolymer is then blended with photoinitiator Irgacure 184 (0.5 wt.%) and crosslinker (0.12 wt.% HDDA), and a vacuum pump is used to create a vacuum to remove any bubbles from the mixture. The blend is then coated with a thickness of 100 µm between two siliconized PET films (50 µm each). Further conversion to 100% polymer is initiated by irradiation with a Heraeus UV LED lamp (wavelength 365 nm) with a UV dose of 3000 mJ / cm³. 2 . Comparison example V2

[0083] A reactor conventional for radical polymerizations is charged with 320 g of 2-ethylhexyl acrylate, 60 g of 4-hydroxybutyl acrylate, and 20 g of methacrylic acid, as well as the photoinitiator Irgacure 651 at a concentration of 0.01 wt.%. After passing nitrogen gas through the reactor for 45 minutes while stirring, the reactor is sufficiently purged of oxygen. Subsequently, the reactor is illuminated with a (UV) LED lamp with an intensity of 3000 [mJ / cm 2 ] for 10 min, the reaction is started until a monomer-polymer mixture with a defined viscosity is obtained.

[0084] The prepolymer is then blended with photoinitiator Irgacure 184 (0.5 wt%), and a vacuum pump is used to create a vacuum to remove any bubbles. The blend is then coated with a thickness of 100 µm between two siliconized PET films (50 µm each). Further conversion to 100% polymer is initiated by irradiation with a Heraeus UV LED lamp (wavelength 365 nm) with a UV dose of 3000 mJ / cm². 2 .

[0085] The sample samples described above are each laminated on both sides to the substrate B2. The substrate is pretreated on both sides with corona (in air at 120 W min / m 2 ). Example B1

[0086] The PU dispersion Impranil DL1116 (Covestro) is mixed with 2% of the crosslinker Imprafix 2794 (Covestro) and 0.6% of the thickener Ortegol PV301 (Evonik), based on the PU solids content, and the mixture is homogenized using a beaker stirrer. A film is then applied to a siliconized PET film using a doctor blade coating method, resulting in a 50 µm thick PU film after drying. After coating, the film is first evaporated for 30 minutes at room temperature and then dried for 15 minutes at 120 °C. After cooling, the resulting film is covered with a second siliconized PET film. Example B2

[0087] Elastollan L1185A (BASF) was used as a granulate. A 50 µm thick film was produced using an extrusion process familiar to those skilled in the art. This film is also protected on both sides by a co-extruded PE film. Example B V1

[0088] The PU dispersion Impranil DLCF (Covestro) is mixed with 2% of the crosslinker Imprafix 2794 (Covestro) and 0.6% of the thickener Ortegol PV301 (Evonik), based on the PU solids content, and the mixture is homogenized using a beaker stirrer. A film is then applied to a siliconized PET film using a doctor blade in such a way that, after drying, a 50 µm thick PU film is obtained. After coating, the film is first evaporated for 30 minutes at room temperature and then dried for 15 minutes at 120 °C. After cooling, the resulting film is covered with a second siliconized PET film. Example B V2

[0089] N5650M (Nupro) was used as an already extruded film. Abbreviations: 4-HBA 4-Hydroxybutylacrylate 2-EHA 2-Ethylhexyl acrylate n-BA n-butyl acrylate LA Lauryl acrylate 2-PHA 2-Propylheptyl acrylate IBOA Isobornyl acrylate MA Methyl acrylate tBA t-butyl acrylate N75 Networker

[0090] The compositions of the example formulations are summarized in Tables 1 and 2. Unless otherwise stated, the data refer to wt.%. Table 1a: Tg<0°C Tg>0°C Example . 4-HBA 2-EHA n-BA LA 2-PHA IBOA MA t-BA A1 20 35 - - - 45 - - A2 12 - 40 20 28 - - - A3 20 - 27 - - - 25 28 V1 10 - 57 - - - 20 13 Table 1b: Example . Monomer content temperature N75 Proportion of reactive monomers A1 50% 40 °C 0,3 0% A2 45% 40 °C 0,1 0% A3 40% 65 °C - 8% V1 40% 65 °C - 8% Table 2a Tg<0°C Tg>0°C Example . 4-HBA 2-EHA n-BA LA 2-PHA IBOA MA t-BA A4 30 40 - - - - - 30 A5 15 80 - - - - - 5 V2 15 80 - - - - - 5 Table 2b: Example . UV dose [mJ / cm 2 ] Initiator concentration HDDA A4 3000 0.2% Irgacure 184 0,1 A5 3000 0.5% Irgacure 184 0,12 V2 3000 0.5% Irgacure 184 0

[0091] Tables 3 and 4 show the optical and mechanical properties of the exemplary pressure-sensitive adhesives. Table 3 Example (plus carrier B2) Removable F stripp [N / cm] Micro shear displacement 200 g, 40°C, 15 min [µm] Optical properties transmission Haze b-value refractive index A1 Yes 15 71 99,6 0,24 0,04 1,472 A2 Yes 11 441 99,2 0,12 -0,07 1,471 A3 Yes 13,6 218 99,3 0,29 0 1,472 V1 no > 20 > 2000 99,6 0,43 -0,06 1,473 A4 Yes 12 27 99,8 0,35 0,06 1,472 A5 Yes 10,5 126 99,5 0,41 0,04 1,472 V2 no > 20 > 2000 99,4 0,28 0,01 1,472 Table 4a Example plus dimensions A4 removable F stripp [N / cm] Tensile force at 200% [MPa] Elongation at break [%] Maximum tensile force [n / mm 2 ] B1 Yes 5 2,2 765 34 B2 Yes 12 18,9 512 55,3 B V1 No 11 11,7 280 23,5 B V2 Not non-destructive 17,5 33,8 342 52,5 Table 4b: Optical properties Example plus dimensions A4 transmission Haze b-value refractive index B1 99,1 0,32 0,08 1,472 B2 99,8 0,35 0,06 1,473 B V1 99,3 0,40 0,09 1,472 B V2 99,6 0,27 0,02 1,472

[0092] All adhesive tapes according to the invention could be removed without damage, whereby the force F required for removal Strippwas not more than 15 N / cm in each case. In contrast, non-destructive removal of the adhesive tape B V2 was not possible. In the other comparative examples, it was already possible to determine the force F required for removal. stripp The adhesive tape was torn off. Although the non-inventive adhesive tapes exhibited good optical properties, the advantageous combination of optical properties and mechanical properties achieved by the inventive adhesive tapes could not be achieved. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] EP 1 418 212

[0003] EP 0 761 793

[0004] US 2017 / 158919

[0005] US 2017 / 0158918

[0006] WO 2012 / 087804

[0009] WO 2009 / 089137

[0011] EP 1 674 544

[0021]

Claims

[1] Removable adhesive tape comprising: ◯ an elastic support, the support having an elongation of at least 300% and a maximum tensile force at 200% elongation of 20 MPa, determined in accordance with DIN 53504; and ◯ an optically clear acrylate-based pressure-sensitive adhesive applied to both sides of the carrier, characterized by that the pressure-sensitive adhesive has a microshear displacement of less than 2 mm, determined according to method MSW at a load of 200 g for 15 minutes, a layer thickness of 100 µm and a temperature of 40 °C. [2] Adhesive tape according to claim 1, characterized bythat the carrier material is selected from the group consisting of styrene block copolymers, natural rubber, polyisoprene, polybutadiene, polychloroprene rubber, butyl rubber, EPDM rubber, ethylene-propylene copolymers, polyurethanes, vinyl copolymers, ethylene-vinyl acetate copolymers, vinyl chloride-acrylate copolymers, polyether esters, polyether amides, polyester amides, polyether amide block copolymers, polycarbonate-polyester copolymers, ethylene-acrylate copolymers-ABS, copolymers and mixtures and blends thereof. [3] Adhesive tape according to claim 2, characterized by that the carrier material is selected from polyurethanes, in particular thermoplastic polyurethanes (TPU) and dispersion polyurethanes (PUD), aromatic polyurethanes, aliphatic polyurethanes, polyester-polyol-based polyurethanes, polyether-polyol-based polyurethanes, polycarbonate-based polyurethanes and hybrids and mixtures thereof, wherein the polyurethane may be crosslinked or uncrosslinked. [4] Adhesive tape according to at least one of the preceding claims, characterized by that the pressure-sensitive adhesive is selected from the group consisting of solvent-containing and solvent-free acrylate adhesives, in particular copolymers based on acrylic acid / methacrylic acid and their esters with C1 to C25 atoms, maleic, fumaric, itaconic acid and their esters, substituted (meth)acrylamides, other vinyl compounds, such as vinyl esters, vinyl acetate, vinyl alcohol and / or their esters; compounds of acrylate copolymers and resins; compounds of various acrylate copolymers. [5] Adhesive tape according to at least one of the preceding claims, characterized bythat the pressure-sensitive adhesive is obtained from a monomer mixture which, as a homopolymer, has a glass transition temperature, determined by DSC, of not more than 0 °C, wherein the monomers are preferably selected from the group consisting of 2-ethylhexyl acrylate, n-butyl acrylate, propylheptyl acrylate, lauryl acrylate, isodecyl acrylate, isooctyl acrylate, n-octyl acrylate, stearyl acrylate, isostearyl acrylate, iso-C17 acrylate, ethylene diglycol acrylate, 2-ethylhexyl diglycol acrylate, 2-(2-ethoxyethoxy)ethyl acrylate and mixtures thereof. [6] Adhesive tape according to at least one of the preceding claims, characterized bythat the pressure-sensitive adhesive is obtained from a monomer mixture which, as a homopolymer, has a glass transition temperature, determined by DSC, of at least 0 °C, wherein the monomers are preferably selected from the group consisting of dihydrodicyclopentadienyl acrylate, isobornyl (meth)acrylate, methyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, stearyl methacrylate, tert-butyl (meth)acrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl (meth)acrylate, ethyl methacrylate, N-vinylpyrrolidone, n-vinylcaprolactam, dimethylacrylamide, diethylacrylamide, 4-acryloylmorpholine, phenoxybenzyl (meth)acrylate and mixtures thereof. [7] Adhesive tape according to at least one of the preceding claims, characterized bythat the pressure-sensitive adhesive consists of a monomer mixture comprising hydroxy-containing monomers, wherein the monomers are preferably selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 1,4-cyclohexanedimethanol mono (meth)acrylate, 1-glycerol (meth)acrylate, 2-hydroxyethyl (meth)acrylamide, N-hydroxypropyl (meth)acrylamide, vinyl alcohol and allyl alcohol and mixtures thereof. [8] Adhesive tape according to at least one of the preceding claims, characterized by that the adhesive tape has at least one of the following properties: ◯ a transmission of at least 95%, determined according to the “Transmission Method”; ◯ a b-value of less than 1.5, determined according to the “b-value method” ◯ a haze of less than 1.5, determined according to the “Haze Method” ◯ a refractive index nD of 1.45 to 1.53, determined according to the "Refractive Index Method" [9] A method for producing an adhesive tape according to at least one of the preceding claims, characterized by that a composite of adhesive and carrier is created, wherein the carrier is arranged between two layers of adhesive. [10] Method according to claim 9, characterized by that a pressure-sensitive adhesive comprising acrylates having a glass transition temperature of less than, equal to or greater than 0 °C and 5 to 30 wt.% of hydroxy-containing acrylates, a monomer content at the start of polymerization of 35 to 55 wt.% and • in ethyl acetate with a regulating solvent component • polymerized using an azo-based radical initiator which has a maximum temperature of 80 °C with a half-life of 10 h, • with more than 0.02 wt.% isocyanate-based crosslinker based on the solid polymer content • and optionally mixed with other reactive monomers in a total proportion of a maximum of 10 wt.% based on the solid polymer content, coated on a siliconized liner film, dried and then a composite is created with the carrier. [11] Method according to claim 9, characterized by that a pressure-sensitive adhesive comprising 5 to 30 wt.% of hydroxy-containing acrylates and at least 50 wt.% of monomers whose homopolymer has a glass transition temperature of at least 0 °C, a monomer content at the start of polymerization of 35 to 55 wt.% and • in ethyl acetate with a regulating solvent component • polymerized using an azo-based radical initiator which has a maximum temperature of 80 °C with a half-life of 10 h, • optionally with further reactive monomers in a total proportion of maximum 10 wt.% based on the solid polymer content • and optionally mixed with more than 0.02 wt.% isocyanate-based crosslinker based on the solid polymer content, coated on a siliconized liner film, dried and then a composite is created with the carrier. [12] Method according to claim 9, characterized by that a pressure-sensitive adhesive comprising at least 5 wt.% hydroxy-containing acrylates, a photoinitiator content of less than 0.5 wt.% and either • more than 10 wt.% monomers whose homopolymers have a glass transition temperature greater than 0 °C, or • using a crosslinking component with a content of at least 0.01% by weight, preferably at least 0.03%, particularly preferably at least 0.05% by weight, based on the solid polymer content or • more than 10 wt.% monomers whose homopolymers have a glass transition of greater than 0 °C and using a crosslinking component with a content of at least 0.01 wt.%, preferably at least 0.03 wt.%, particularly preferably at least 0.05 wt.%, based on the solid polymer content, coated between two siliconized liners via a UV syrup process, polymerized under UV light and then a composite is created with the carrier. [13] Display comprising an adhesive tape according to at least one of claims 1 to 8. [14] Use of an adhesive tape according to at least one of claims 1 to 8 for the production of displays.