PRESSURE-ADHESIVE ELECTROLYTE

Description

[0001] The invention relates to a pressure-sensitive adhesive polymer electrolyte and a method for providing the pressure-sensitive adhesive polymer electrolyte in the form of an adhesive tape, so that it can be processed more easily than known liquid or solid electrolytes into complete electrochemical systems or cells such as batteries, sensors, or electrochromic cells. These electrochemical systems or cells generally consist of carrier materials, current collectors, anode materials, cathode materials, and the electrolyte.

[0002] Electrolytes are now widely used in various applications, ranging from batteries and accumulators to electrochromism, i.e. the use in electrochromic systems.

[0003] Electrolytes are generally chemical compounds that exist in solid, liquid, or dissolved form, dissociated into ions. These chemical compounds move along the field lines under the external influence of an electric field. However, the surrounding matrix (polymer, inorganic material, ceramic, foil) together with the dissociated chemical compound (conducting salt) is also often referred to as an electrolyte. The latter, more comprehensive definition will be used below.

[0004] The core function of an electrolyte is the ionic conductivity of at least one ion species, while the electrolyte remains largely chemically inert toward other chemical components of a system and neither conducts, absorbs, nor reacts with them. Electrochemical cells, such as batteries or accumulators, electrochromic systems, or even electrochemical-based sensors, are typically composed of two half-cells that must be chemically and electrically separated from each other except for the flow, i.e., the exchange, of certain ions to enable their intended function.

[0005] All existing or known electrolytes for separating half-cells have one major disadvantage: they must be joined to the half-cells through complex processes and product designs.

[0006] State-of-the-art electrolytes are known that must be mechanically joined, for example, by clamping the flat or web-like materials, winding them tightly with appropriate web tension, or bonding them to the sides with a third material. Electrolytes are also known that themselves act as an adhesive by chemically curing after the half-cells are brought together. These are applied in liquid form to one half-cell, brought together with the second half-cell, and then cured. Curing is initiated either thermally or by actinic radiation, such as UV radiation.

[0007] The disadvantage is that curing represents a cost-intensive additional process step that requires time, development effort, and complex process engineering and process monitoring methods. Furthermore, the joining of half-cells in batteries or electrochromic systems using the liquid, viscous electrolyte leads to significant thickness variations, which prevent the creation of a product design with precisely defined thickness and thus product properties. Especially with wound (cylindrical cells) or folded (pouch cells) multilayer structures of the functional layers (current collectors, anode materials, cathode materials, electrolytes), in-process control of a homogeneous layer structure is not possible, resulting in costly scrap. To reduce scrap, some attempts are made to inject uncured electrolyte prepolymer ("syrup") into the cell after winding and then cure it.But even with this process, the layer thickness cannot be monitored or precisely controlled.

[0008] In addition to ease of manufacture and application, other essential properties of the electrolyte include high ionic conductivity over a wide temperature range, cycling stability, fire safety, optical transparency, safety, recyclability, and chemical stability compared to the other active materials. Furthermore, the ionic conductivity decreases with increasing polymer (e.g., PMMA) content in the mixture. If the polymer content is too low, the dimensional stability is no longer sufficient to reliably prevent mechanical damage and short circuits, so a porous film membrane must be incorporated into the electrolyte layer, which complicates and increases the cost of the process.

[0009] Gel polymer electrolytes (GPEs) are typically based on polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), or polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) (Dong Zhou, Li-Zehn Fan, Huanhuan Fan, Qiao Shi: Electrochemical performance: Electrochemical performance of trimethylolpropanetrimethylacrylate-based GPE prepared by in situ thermal polymerization; Electrochimica Acta 89:334-338, Feb. 2013). Typically, very high proportions of plasticizer / conductive salt mixtures of up to 97% are used to achieve high ionic conductivity. These polymer electrolytes exhibit low dimensional stability, meaning they cannot be wound onto large jumbo reels without oozing. While they may exhibit tack, they lack cohesion and are therefore unsuitable for bonding electrochemical half-cells.In the examples mentioned, the porous film carrier Celgard 2400 (Celgard LLC, USA) is also used to produce a functional cell.

[0010] For example, DE 10 2014 108 012 A1 discloses conducting salts such as lithium [3,5-bis(trifluoromethyl)pyrazolide] or LiTSFI. These conducting salts can be used to produce hydrolysis-stable and chemically inert liquid and polymer electrolytes. DE 10 2008 062 129 A1 describes a pressure-sensitive adhesive with high permittivity and a high glass transition temperature.

[0011] It is an object of the present invention to at least partially overcome the aforementioned disadvantages and to provide an electrolyte which is self-adhesive (pressure-sensitive adhesive) and has a defined thickness which preferably remains constant regardless of mechanical stresses during the process and during subsequent use.

[0012] Furthermore, it is an object of the invention to provide an electrolyte which can be easily applied to the first half-cell by lamination in the manufacturing process and can be connected to the second half-cell by lamination.

[0013] The object is achieved by a pressure-sensitive adhesive polymer electrolyte having the features of claim 1, i.e. by a pressure-sensitive adhesive polymer electrolyte having an adhesive strength according to test A described in the description of more than 1 N / cm and an ionic conductivity according to test B described in the description of more than 10 -6< (Ohm*cm) -1< , i.e. 10 -6< S / cm, produced by polymerization of a mixture comprising at least the following components: 5 - 60 wt.%, preferably 10 - 50 wt.%, more preferably 10 - 40 wt.%, in particular 15 - 30 wt.%, of acrylate monomer from the group of (meth)acrylic acid esters having 4 - 15 carbon atoms, wherein the number of carbon atoms refers in each case to the entire molecule, i.e. to the acid component and alcohol component together, and the acrylate monomer as a homopolymer, i.e. homopolymerized, would have a T g according to Test C described in the description of less than -30 °C, 10 - 80 wt.%, preferably 35 - 75 wt.%, more preferably 40 - 70 wt.%, in particular 50 - 70 wt.%, of acrylate monomer from the group of (meth)acrylic acid esters having 4 - 25 carbon atoms and containing at least one heteroatom, wherein the number of carbon atoms refers in each case to the entire molecule, i.e. to the acid component and alcohol component together, the heteroatom in addition to the two O atoms of the ester functionality and the acrylate monomer as a homopolymer, i.e.homopolymerized, would have a T g according to test C described in the description of less than +100 °C, 0.05 - 10 wt.%, preferably 0.1 - 2 wt.%, in particular 0.1 - 0.5 wt.%, initiator, wherein the initiator is preferably a thermal initiator and / or photoinitiator, particularly preferably photoinitiator, 2 - 13 wt.%, preferably 3 - 10 wt.%, in particular 4 - 8 wt.%, conductive salt, optionally plasticizer, such as 5 to 50 wt.%, preferably 10 to 30 wt.% and in particular 15 to 25 wt.% plasticizer, and optionally solvent, which is typically at least partially, such as substantially completely, removed after the polymerization. wherein optionally one or more of the components are added at least partially, such as completely, only during or after the polymerization.

[0014] Preferred embodiments of the polymer electrolyte can also be found in the dependent claims.

[0015] According to the present application, only those solvents (compounds) are considered solvents which have a boiling point of less than 100°C at atmospheric pressure, i.e. 1013 mbar. Solvents with a boiling point of 100°C or more at 1013 mbar and solvents which do not have a boiling point at 1013 mbar but decompose at 100°C or more, are considered plasticizers within the meaning of the present application. According to the invention, the solvent is not taken into account when specifying the weight proportions of the components, but plasticizers such as ethylene carbonate (EC) or diethyl carbonate (DEC) are. If solvent within the meaning of the present application is used in the polymerization according to the invention, it is preferably essentially removed after the polymerization, in particular because the solvent can adversely affect the stability of the electrolyte and the subsequent electrochemical cell due to its low boiling point.

[0016] Components optionally added during or after polymerization are of course already included in the stated weight proportions.

[0017] According to the present invention, the term "(meth)acrylic acid ester" encompasses both methacrylic acid esters and acrylic acid esters. The number of carbon atoms in the (meth)acrylic acid esters also refers to the entire molecule, i.e., the acid component and alcohol component together.

[0018] In the acrylate monomer from the group of (meth)acrylic acid esters having 4-25 carbon atoms and containing at least one heteroatom which, as a homopolymer, would have a T g according to Test C of less than +100 °C, the heteroatom is preferably O, S or N, more preferably O or N and in particular O. It is clear to the person skilled in the art that the at least one heteroatom is present in the acrylate monomer in addition to the two O atoms (oxygen atoms) of the ester functionality, ie (C=O)O. The at least one heteroatom is typically contained in the hydrocarbon radical of the alcohol component of the (meth)acrylic acid ester.

[0019] The acrylate monomer from the group of (meth)acrylic acid esters with 4 - 15 carbon atoms, which as a homopolymer would have a T g according to test C of less than -30 °C, preferably contains no heteroatom apart from the two O atoms of the ester functionality.

[0020] The acrylate monomer from the group of (meth)acrylic acid esters having 4-25 carbon atoms and containing at least one heteroatom, which as a homopolymer would have a T g according to Test C of less than 100°C, preferably consists at least partially of acrylate monomer which, as a homopolymer, would have a T g according to Test C of at least -30°C, in particular at least 0°C. This typically has a beneficial effect on several properties of the pressure-sensitively adhesive electrolyte, such as cohesion, shear strength, and heat resistance. In a preferred embodiment, the mixture to be polymerized comprises 15 to 50% by weight, preferably 25 to 40% by weight, of acrylate monomer from the group of (meth)acrylic acid esters having 4-25 carbon atoms and containing at least one heteroatom, which, as a homopolymer, has a T g according to Test C of -30°C to less than +100°C, preferably 0°C to 50°C.

[0021] The acrylate monomer from the group of (meth)acrylic acid esters with 4-15 carbon atoms, which as a homopolymer would have a T g according to Test C of less than -30 °C, can be one or more monomers. The same applies to the acrylate monomer from the group of (meth)acrylic acid esters with 4-25 carbon atoms and containing at least one heteroatom, which as a homopolymer would have a T g according to Test C of less than 100 °C. By selecting suitable acrylate monomers to be polymerized and their amount, properties such as the glass transition temperature T g and the polarity of the pressure-sensitive polymer electrolyte can also be specifically adjusted.

[0022] The glass transition temperatures T g of the homopolymers mentioned typically refer to an infinite molecular weight, i.e., with respect to the homopolymers, T g typically means T g ∞<. The person skilled in the art knows that low molecular weights increase chain mobility and thus lower T g. The empirical rule applies T g = T g ∞ − K M where T g is the glass transition temperature of a polymer at the number-average molecular weight M, i.e., M n , K is a constant factor dependent on the polymer type, and T g ∞< is the glass transition temperature of the polymer at infinite molecular weight (see Bernd Tieke: "Macromolecular Chemistry - an Introduction", VCH-Verlag, 2004, p. 270 f.). Thus, if the measured T g values ​​for a given polymer are plotted against K / M for different number-average molecular weights M, the resulting Y-axis intercept is T g ∞<.

[0023] The pressure-sensitive adhesive polymer electrolyte according to the invention is preferably characterized by an oxidative stability according to Test I of more than 2.5 V.

[0024] In a further embodiment, the pressure-sensitive adhesive polymer electrolyte according to the invention is characterized in that the polymer of the polymer matrix has a relative permittivity ε r according to Test J of more than 3.5, preferably more than 4.5.

[0025] The electrolyte according to the invention can be used in batteries, but also in transparent electrochromic systems, as the electrolyte according to the invention exhibits only minimal aging effects, thus remaining chemically stable for a long time, and enables stable and weather-resistant bonding even in outdoor applications over years, while retaining its transparent, high-quality optical properties. This stability is possible because monomers, conductive salts, and, where used, plasticizers were found that, in the combination according to the invention, do not interact with UV light and are prone to decomposition reactions.

[0026] The object is further achieved by a process for producing the pressure-sensitively adhesive polymer electrolyte according to the invention. According to the process, a mixture comprising at least the following components is polymerized: 5 - 60 wt.%, preferably 10 - 50 wt.%, more preferably 10 - 40 wt.%, in particular 15 - 30 wt.%, of acrylate monomer from the group of (meth)acrylic acid esters having 4 - 15 carbon atoms, which as a homopolymer would have a T g according to Test C of less than -30°C, 10 - 80 wt.%, preferably 35 - 75 wt.%, more preferably 40 - 70 wt.%, in particular 50 - 70 wt.%, of acrylate monomer from the group of (meth)acrylic acid esters having 4 - 25 carbon atoms and containing at least one heteroatom, which as a homopolymer would have a T g according to Test C of less than 100°C, 0.05 - 10 wt.%, preferably 0.1 - 2 wt.%, in particular 0.1 - 0.5 wt.%, of initiator, wherein the initiator is preferably a thermal initiator and / or Photoinitiator is, particularly preferably photoinitiator, 2 - 13 wt.%, preferably 3 - 10 wt.%, in particular 4 - 8 wt.%, conductive salt, optionally plasticizer, such as 5 to 50 wt.%, preferably 10 to 30 wt.% and in particular 15 to 25 wt.-% plasticizer, and optionally solvent, which is typically at least partially, such as substantially completely, removed after polymerization. wherein optionally one or more of the components are added at least partially, such as completely, only during or after the polymerization.

[0027] According to the invention, the solvent is not taken into account when specifying the weight proportions of the components.

[0028] The invention further relates to a pressure-sensitive adhesive tape comprising at least one layer of the pressure-sensitively adhesive polymer electrolyte according to the invention, wherein the pressure-sensitive adhesive tape is preferably double-sided adhesive, i.e., a double-sided adhesive tape, and in particular a transfer adhesive tape. The general term "adhesive strip" (pressure-sensitive adhesive strip), synonymously also "adhesive tape" (pressure-sensitive adhesive tape), encompasses, within the meaning of this invention, all flat structures such as films or film sections extended in two dimensions, tapes with an extended length and a limited width, tape sections, and the like, and ultimately also diecuts or labels. The pressure-sensitive adhesive tape thus has a longitudinal dimension (x-direction) and a width dimension (y-direction). The pressure-sensitive adhesive tape also has a thickness (z-direction) running perpendicular to both dimensions, the width dimension and longitudinal dimension being many times greater than the thickness.The thickness is as uniform as possible, preferably exactly the same, across the entire surface area of ​​the pressure-sensitive adhesive tape, determined by its length and width. The pressure-sensitive adhesive tape according to the invention is in particular in web form. A web is understood to be an object whose length (extension in the x-direction) is many times greater than its width (extension in the y-direction), and whose width is approximately, preferably exactly the same, along its entire length. Advantageously, the exposed surfaces of the pressure-sensitive adhesive tape can be provided with materials coated on both sides with an anti-adhesive coating, such as a release paper or a release film, also called a liner, as a temporary carrier. A liner (release paper, release film) is not a component of a pressure-sensitive adhesive tape, but merely an aid for its production, storage, and / or further processing by punching.Furthermore, unlike an adhesive tape backing, a liner is not permanently bonded to an adhesive layer. The pressure-sensitive adhesive tape preferably consists of a single layer of the pressure-sensitively adhesive polymer electrolyte according to the invention, so that the pressure-sensitive adhesive tape represents a single-layer system. Such a single-layer, double-sided self-adhesive, i.e., pressure-sensitive adhesive tape, i.e., double-sided adhesive tape, is also referred to as a "transfer tape."

[0029] The invention further relates to a product roll comprising (a) a roll core and (b) a web-shaped pressure-sensitive adhesive polymer electrolyte according to the invention or a pressure-sensitive adhesive tape according to the invention, wherein the pressure-sensitive adhesive polymer electrolyte or the pressure-sensitive adhesive tape is wound in multiple layers onto the roll core in the form of an Archimedean spiral.

[0030] The invention also relates to the use of the pressure-sensitive adhesive polymer electrolyte or pressure-sensitive adhesive tape according to the invention in an electrochromic glazing or a battery.

[0031] The invention further relates to an electrochromic system comprising a first half-cell A and a second half-cell B, wherein the two half-cells A and B are connected to one another over their entire surface or over part of their entire surface via a pressure-sensitive adhesive polymer electrolyte according to the invention or a pressure-sensitive adhesive tape according to the invention, wherein preferably the first half-cell A has a flat, electrically conductively coated polymer or glass substrate body and an anode material applied over its entire surface or partially is applied to the conductively coated side, and the second half-cell B likewise has a flat, electrically conductively coated polymer or glass substrate body and a cathode material applied over its entire surface or partially is applied to the electrically conductively coated side.

[0032] Furthermore, the invention relates to a method for producing an electrochromic system in which a first half-cell A and a second half-cell B are joined together to form an electrochromic system by laminating a pressure-sensitive adhesive polymer electrolyte according to the invention or a pressure-sensitive adhesive tape according to the invention, wherein the half-cells A and B are preferably as defined above.

[0033] Furthermore, the invention also relates generally to structures and methods for constructing electrochemical cells as described above, wherein two half-cells are joined by the electrolyte according to the invention. These electrochemical cells are also referred to as batteries when electrical energy is to be stored and released. In this case, half-cells A and B are optimized to be able to absorb a large amount of the cation. Suitable anode materials include, for example, graphite formulations or metallic lithium applied to a conductive electrode that is not necessarily transparent in this case. Suitable cathode materials include, for example, a formulation of lithium iron phosphate mixed with small amounts of graphite and a polyvinylidene fluoride / polyhexafluoropropylene mixture (binder). Various anode and cathode materials for cell production are widely known to those skilled in the art.

[0034] For optimal performance, the pressure-sensitive adhesive electrolyte polymer matrix must have the highest possible permittivity so that it can dissolve the conductive salts it contains in sufficiently high concentrations. In particular, the cations must be mobile and dissociated, while the associated anions can be immobilized by the polymer matrix. Low viscosity, even at low temperatures, is also beneficial for the mobility of the cations. Unfortunately, pressure-sensitive adhesive polymer systems with high permittivity have proven to be less viscous, and due to the high glass transition temperature, the typical application temperature is close to or even below the glass transition temperature, which is unfavorable for ion mobility. Surprisingly, however, it has been shown that despite the high glass transition point, the ionic conductivity of pressure-sensitive adhesives according to the invention can achieve high values.

[0035] Electrolytes according to the invention are self-adhesive, meaning they have a pressure-sensitive adhesive and possess a solid structure with a defined thickness even before or without curing. They can be directly joined to the half-cell components in a simple process step by simple lamination. The complexity of the overall system is reduced if the curing required after joining the half-cells is eliminated. The absence of chemically active components eliminates the risk of undesirable side reactions with active components of other half-cell active materials.

[0036] The electrolyte according to the invention is pressure-sensitive, i.e. it represents a pressure-sensitive adhesive - both as a chemically inert system that does not require further curing, and as a reactive pressure-sensitive adhesive whose lamination can be followed by a curing process.

[0037] For the purposes of the invention, a pressure-sensitive adhesive is understood, as is common parlance, to be a substance that is permanently tacky and adhesive, at least at room temperature. A characteristic of a pressure-sensitive adhesive is that it can be applied to a substrate by pressure and remains adhered there, although the pressure to be applied and the duration of this pressure are not defined in more detail. In general, but fundamentally dependent on the exact type of pressure-sensitive adhesive and the substrate, the temperature and the humidity, the application of short-term, minimal pressure, which does not go beyond a light touch for a brief moment, is sufficient to achieve the adhesive effect; in other cases, a longer exposure time of higher pressure may be necessary.

[0038] Pressure-sensitive adhesives have special, characteristic viscoelastic properties that lead to their permanent tack and adhesive strength. They are characterized by the fact that, when mechanically deformed, both viscous flow processes and the development of elastic restoring forces occur. The respective proportions of both processes are in a specific relationship to each other, depending on the precise composition, structure, and degree of crosslinking of the pressure-sensitive adhesive, as well as the speed and duration of the deformation and the temperature.

[0039] The viscous flow component is necessary to achieve adhesion. Only the viscous components, often caused by macromolecules with relatively high mobility, enable good wetting and flow onto the substrate to be bonded. A high proportion of viscous flow leads to high pressure-sensitive adhesiveness (also referred to as tack or surface stickiness) and thus often to high adhesion. Highly cross-linked systems, crystalline, or glass-like polymers, are generally not or at least only slightly tacky due to the lack of flowable components.

[0040] The proportional elastic restoring forces are necessary to achieve cohesion. They are caused, for example, by very long-chain and highly entangled macromolecules, as well as by physically or chemically cross-linked macromolecules, and enable the transfer of forces acting on an adhesive bond. They ensure that an adhesive bond can adequately withstand continuous loading, for example, in the form of permanent shear stress, over an extended period of time.

[0041] For a more precise description and quantification of the degree of elastic and viscous components as well as the relationship between the components, the storage modulus (G') and loss modulus (G"), which can be determined using Dynamic Mechanical Analysis (DMA), are used. G' is a measure of the elastic component, G" a measure of the viscous component of a material. Both parameters depend on the deformation frequency and the temperature.

[0042] These parameters can be determined using a rheometer. The material under test is subjected to a sinusoidal oscillating shear stress, for example, in a plate-on-plate arrangement. Shear stress-controlled devices measure the deformation as a function of time and the temporal offset of this deformation relative to the application of the shear stress. This temporal offset is referred to as the phase angle δ.

[0043] The storage modulus G' is defined as follows: G' = (τ / γ) • cos(δ) (τ = shear stress, γ = deformation, δ = phase angle = phase shift between shear stress and deformation vector). The definition of the loss modulus G" is: G' = (τ / γ) • sin(δ) (τ = shear stress, γ = deformation, δ = phase angle = phase shift between shear stress and deformation vector).

[0044] A composition is considered to be a pressure-sensitive adhesive and is defined as such within the meaning of the invention in particular if, at 23 °C, in the deformation frequency range from 10 0< to 10 1< rad / sec, both G' and G" are at least partly in the range from 10 3< to 10 7< Pa. "Partly" means that at least a section of the G' curve lies within the window spanned by the deformation frequency range from 10 0< to 10 1< rad / sec (abscissa) and the range of G' values ​​from 10 3< to 10 7< Pa (ordinate), and if at least a section of the G" curve also lies within the corresponding window. Photoinitiators and crosslinkers:

[0045] The mixture to be polymerized according to the invention, from which the pressure-sensitively adhesive polymer electrolyte according to the present invention arises, contains 0.05-10 wt. %, preferably 0.1-2 wt. %, in particular 0.1-0.5 wt. % of initiator, preferably thermal initiator and / or photoinitiator, particularly preferably photoinitiator. The photoinitiator is typically a UV initiator. Accordingly, the polymerization taking place according to the invention is preferably a UV polymerization. If a mixture of several initiators is used, the above weight proportions typically refer to the total amount of initiators. The initiator used according to the invention is preferably an initiator that initiates a free-radical polymerization. Accordingly, the polymerization taking place according to the invention is preferably a free-radical polymerization.

[0046] The UV polymerization for syrup production as well as on the coated web can be carried out, for example, with the following photoinitiators, i.e. light-active initiators: 2,2-dimethoxy-2-phenylacetophenone (DMPA, 340 nm, 250 nm), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BAPO, 295 nm, 370 nm), iodonium-(4-methylphenyl)[4-(2-methylpropyl)phenyl]-hexafluorophosphate (242 nm), (2,2'-bithiophen-5-yl)(4-(N,N'-diethylaminophenyl)ketone (THBP), 6,6"-(((1E, 1'E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis(4,1-phenylene))bis(1,3,5-triamine-2,4-diamine)) (400 nm). In addition to the initiators mentioned, other known initiators from the following classes can be used: alpha-amino ketones, metallocenes, iodonium salts, alpha-hydroxy ketones, or phosphines. Preferably, thermal stability up to at least 50 °C is present.

[0047] Depending on the energy of the radicals formed during initiator fission, these can be limited to initiating acrylate polymerization or can also cause crosslinking reactions, such as 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-trianzine (MTT). During solvent polymerization or syrup production, crosslinking of the chains is undesirable in order to keep the viscosities for the coating low. During UV polymerization, crosslinking photoactive crosslinkers can be added in the second polymerization step. These can also be optionally polymerized into the chains.When using 2-oxo-1,2-diphenylethyl acrylate (benzoin acrylate) or its analogues, polymerization in the UV channel at a wavelength between 300 and 400 nm produces polymers that can be crosslinked briefly and intensively with UV radiation at 250 nm after polymerization in the UV channel, activating the polymerized benzoin acrylate building blocks. These crosslinkers can also be polymerized during thermally initiated solvent polymerization and later activated with UV radiation after drying. Crosslinking without the use of protic functional groups is essential to produce pressure-sensitive electrolytes according to the invention, ensuring electrochemical and chemical stability with respect to the active materials used in the cell.

[0048] Benzophenone methacrylate (Visiomer 6976, 300 nm) and its analogues can also be used, with their known advantages and disadvantages. These initiators reduce contamination with small molecules, but require more time to react due to the bimolecular reaction. Crosslinking must take place under inert conditions.

[0049] In addition to the grafting initiators, the polymer matrix can also be crosslinked with crosslinking multifunctional acrylates, i.e. molecules that have more than one acrylate group. Suitable examples include hexanediol diacrylate (HDDA), ethoxylated trimethylolpropane triacrylate (ETPTA), 1,9-nonanediol dimethacrylate, 1,6-hexanediol dimethacrylate, di(trimethylolpropane)tetraacrylate, di(ethylene glycol)diacrylate (Di(EG)DA), bis(2-methacryloxyethyl phosphate, di(ethylene glycol)timethacrylate (Di(EG)DM), bisphenol A bis(2-hydroxypropyl)acrylate, ethylene glycol dimethacrylate (EGDM), dipropylene glycol diacrylate, trans-1,4-cyclohexanediol dimethacrylate, (Di(PG)DA), 1,3-glyceryl dimethacrylate, 1,10-decanediol dimethacrylate, dipropylene glycol dimethacrylate (Di(PG)DM), 1,4-diacryloylpiperazine, ethylene glycol divinyl ether (EGDVE), Diethylene glycol diacrylate, diethylene glycol divinyl ether (Di(EG)DVE), diethylene glycol dimethacrylate, triethylene glycol dimethacrylate (Tri(EG)DM), ethylene glycol diacrylate,Dipentaerythritol pentaacrylate (DPentA), trimethylolpropane triacrylate (TMPTA), trimethylolpropane triacrylate (PO3-TMPTA), propoxylated trimethylolpropane triacrylate (PO6-TMPTA), poly(ethylene glycol) diacrylate (PAI) and polyethylene glycol timethacrylate.

[0050] As long as all functional groups are converted in the final product, protic groups can also be used for crosslinking. The following crosslinkers or crosslinking systems are then also suitable: isocyanate crosslinkers, epoxy-based crosslinkers, melamine-based crosslinkers, peroxide-based crosslinkers, metal chelate-based crosslinkers, metal salt-based crosslinkers, carbodiimide-based crosslinkers, oxazoline-based crosslinkers, aziridine-based crosslinkers, amine-based crosslinkers, or silane-based crosslinkers. Combinations of different crosslinkers are also possible. Examples of suitable monomers include: 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 2-hydroxyethyl acrylamide, and N-hydroxypropylacrylamide. In addition to hydroxy monomers with acrylamide groups, hydroxy monomers with ethylene glycol units can also be used.An example of this is hydroxy-terminated propylene glycol acrylate. The groups can also be carboxylic acid groups, carboxylic acid anhydride groups, amide groups, amino groups, urethane groups, or urea units. If two or more of these functional groups are present, they can be identical or independently selected from the functional groups mentioned. Very suitable examples of these according to the invention are acrylic acid or methacrylic acids, N-vinylcaprolactam, N-vinylpyrrolidone, acrylamide, methacrylamide, N-alkylacrylamide, such as N-methylacrylamide, N-alkylmethacrylamides, such as N-methylmethacrylamide, N,N-dialkylacrylamides, such as N,N-dimethylacrylamide, diacetoneacrylamide, N,N-alkylmethacrylamides, such as N,N-dimethylmethacrylamide. Further examples are 4-vinylpyridine, N-vinylphthalimide, and N-vinylformamide.Other highly suitable monomers are monomers with (poly)ethylene glycol segments, with at least two ethylene glycol units present in the monomer. The corresponding monomers can, in particular, be hydroxy-terminated and / or methoxylated.

[0051] When using difunctional crosslinkers, their proportion in the pressure-sensitive adhesive is typically between 0.2 and 10 parts by weight, particularly preferably between 0.5 and 3 parts by weight of crosslinker per 100 parts by weight of the polymer component. When using trifunctional crosslinkers, their proportion is preferably added at 0.02 to 5 parts by weight per 100 parts by weight of the polymer component, particularly preferably 0.05 to 1 part by weight. However, crosslinkers with higher functionality can also be used. Furthermore, several crosslinkers can be used, which may be identical or different in terms of their functionality (for example, a combination of difunctional and trifunctional crosslinkers). The amounts used should then advantageously be adjusted. Solvent:

[0052] As described above, according to the present application, only those solvents (compounds) are considered solvents that have a boiling point of less than 100°C at atmospheric pressure, i.e., 1013 mbar. Solvents with a boiling point of 100°C or more at 1013 mbar and solvents that do not have a boiling point at 1013 mbar but decompose at 100°C or more, however, are considered plasticizers within the meaning of the present application.

[0053] Dry ethyl acetate, for example, can be used as a solvent for the polymerization of the electrolyte's polymer matrix or as an aid for blending the polymer matrix with other components and additives. Its electrochemical stability towards oxidation lies between that of diethyl carbonate (DEC) and the more stable cyclic ethylene carbonate (EC), and it can be dried very quickly and with little energy expenditure. The presence of ethyl acetate further improves the low-temperature properties with regard to ionic conduction. Other solvents can also be used, such as acetonitrile, 1,3-dioxolane, dimethoxyethane, ketones, or ethylene glycol dimethyl ether. All of these solvents can also be used as solvents during polymerization or as integral components of the final polymer electrolyte.

[0054] However, for safety reasons (odor, flammability), one often does not want to contain highly volatile solvents in the electrolyte, especially when the electrochemical system is not encapsulated in aluminum casings or other sturdy housings, as is usual with batteries, but rather between two film substrates, as in electrochromic systems. In this case, the solvent can be removed from the electrolyte after coating with the electrolyte according to the invention by drying it in a drying tunnel. Alternatively, a solvent-free polymerization process such as UV syrup polymerization can be used to produce the polymer matrix.

[0055] If the polymer matrix was produced by solvent polymerization, there are known methods for drying or concentrating the polymer-solvent mixture, such as concentration in an extruder. This limits the impact on side reactions caused by residual solvent after concentration or drying. Plasticizers:

[0056] The pressure-sensitively adhesive polyelectrolyte may contain plasticizers, preferably in a proportion of 5 to 50 wt. %, more preferably in a proportion of 10 to 30 wt. %, in particular 15 to 25 wt. Examples of plasticizers that can be used are cyclic carbonates such as ethylene carbonate (EC), vinylene carbonate (VC), propylene carbonate (PC), butylene carbonate (BC), or fluoroethylene carbonate (FEC), linear carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), or ethyl methyl carbonate (EMC), mixed carbonates, dimethylacetamide, ethyl methanesulfonate (EMS), gamma-butyrolactone, dimethyl sulfoxide, glymes such as diglyme, triglyme, tetraglyme, ethylene glycol diacetate, ketones, or various ethers or polyethers or mixtures thereof. According to the invention, diethyl carbonate (DEC) and / or ethylene carbonate (EC) are particularly preferably used as plasticizers. Dimethylacetamide, for example, can be used without significantly reducing the solubility of the conducting salt.All of the plasticizers mentioned can typically also improve solubility during polymerization and act as an integral component of the final polymer electrolyte. Polymer:

[0057] The aim of the invention is to provide a pressure-sensitive electrolyte, i.e., a pressure-sensitive adhesive (PSA) that exhibits excellent electrolyte function through ionic conduction. Pressure-sensitive adhesives (PSAs) are, as described above, in particular those polymeric materials that—optionally through suitable additives with other components, such as adhesive resins—are permanently tacky and permanently adhesive at the application temperature (unless otherwise defined, at room temperature) and adhere to a variety of surfaces upon contact, in particular adhere immediately (exhibiting a so-called "tack," i.e., stickiness or tackiness).They are capable of sufficiently wetting a substrate to be bonded even at the application temperature without activation by solvents or heat – but usually through the influence of varying degrees of pressure – so that sufficient interactions can develop between the adhesive and the substrate for adhesion. Key influencing parameters include pressure and contact time. The special properties of pressure-sensitive adhesives are due, among other things, to their viscoelastic properties.

[0058] Pressure-sensitive adhesives comprise one or more polymers (in this document, the polymers are collectively referred to as the "polymer component" of the pressure-sensitive adhesive), which may be homopolymers and / or comonomers composed of various monomers that can be polymerized together. The polymer component may already exhibit pressure-sensitive adhesive properties or acquire these properties only after suitable additives, for example, with resins.

[0059] The polymer component can, in principle, be produced from polymers of different chemical nature. The pressure-sensitive adhesive properties can be influenced, among other things, by the type and proportions of the monomers used in the polymerization of the polymers underlying the pressure-sensitive adhesive, their average molecular weight and molecular weight distribution, as well as by the type and amount of additives in the pressure-sensitive adhesive, such as tackifier resins, plasticizers, and the like. Crosslinkers can also be used in polymer production, typically in a proportion of 0.05 to 5 wt. %, preferably 0.1 to 3 wt. %.

[0060] To achieve the viscoelastic properties, the monomers on which the polymers underlying the pressure-sensitive adhesive are based, as well as any other components of the pressure-sensitive adhesive that may be present, are selected in particular such that the pressure-sensitive adhesive has a glass transition temperature (according to DIN 53765) below the application temperature (i.e. usually below room temperature).

[0061] Through suitable cohesion-enhancing measures, such as crosslinking reactions (formation of bridge-forming bonds between macromolecules), the temperature range in which a polymer mass exhibits pressure-sensitive adhesive properties can be expanded and / or shifted. The application range of pressure-sensitive adhesives can thus be optimized by adjusting the flowability and cohesion of the mass.

[0062] According to the invention, the pressure-sensitively adhesive polyelectrolyte contains at least one polyacrylate, i.e., poly(meth)acrylate. A "poly(meth)acrylate" is understood to mean a polymer obtainable by polymerizing acrylic and / or methacrylic monomers and, optionally, further copolymerizable monomers. Typically, the poly(meth)acrylate according to the invention is produced by polymerizing acrylate monomer from the group of (meth)acrylic esters having 4-15 carbon atoms, which, as a homopolymer, would have a T g according to Test C of less than -30°C, acrylate monomer from the group of (meth)acrylic esters having 4-25 carbon atoms and containing at least one heteroatom, which, as a homopolymer, would have a T g according to Test C of less than 100°C, and, optionally, further monomer. The term "(meth)acrylic ester" encompasses both methacrylic esters and acrylic esters.The polymerization of the poly(meth)acrylate is carried out in particular by free radical polymerization of the comonomers used according to known polymerization processes.

[0063] To determine the glass transition temperature of copolymers, the Fox equation can be used (cf. TG Fox, Bull. Am. Phys. Soc. 1 (1956) p. 123), which states that the reciprocal glass transition temperature TG (K) of the copolymer, i.e. 1 / TG , can be calculated from the weight fractions of the comonomers used and the glass transition temperatures of the corresponding homopolymers of the comonomers: 1 T G = w 1 T G , 1 + w 2 T G , 2 where w 1 and w 2 represent the mass fraction of the respective monomer 1 or 2 (wt%) and TG,1 and TG,2 represent the respective glass transition temperature of the homopolymer from the respective monomers 1 or 2 in Kelvin (K).

[0064] In case of more than two comonomers the equation is generalizable to 1 T G = ∑ n w n T G , n

[0065] In the general equation, n represents the number of monomers used, wn the mass fraction of the respective monomer n (wt%) and TG,n the respective glass transition temperature of the homopolymer from the respective monomers n in K.

[0066] The values ​​for the glass transition temperatures of the corresponding homopolymers can also be found in relevant reference works.

[0067] High-molecular-weight polyethylene oxide (PEO), which forms complexes with Li salts, is one of the best polymer matrices (however, its oxidative electrochemical stability is limited to 3.8 V versus Li / Li +<, so a battery can operate up to a maximum of 3 V). However, polymers based on polyvinyl chloride (PVC) and acrylates are also very suitable.

[0068] Poly(vinylidene fluoride / trifluoroethylene) or poly(vinylidene fluoride / hexafluoropropylene) blended with polyethylene oxide or polyethylene oxide / polyacrylonitrile (PEO / PAN) blends are also suitable. Acrylates with ethylene oxide (EO) units in the side chains exhibit higher electrochemical stability and can be operated at up to 4 V (e.g., LFP cells). Copolymers of vinyl chloride, acrylonitrile, methyl methacrylate, ethylene oxide, propylene oxide, epichlorohydrin, vinylidene chloride, vinylidene fluoride, ethylene succinate, and hexafluoropropylene are also suitable. Copolymers of vinylidene fluoride and hexafluoropropylene are also often used as binders for the active materials.

[0069] Polymers based on acrylates are particularly well suited for pressure-sensitive adhesive electrolytes according to the invention because high transparency and weather resistance can be achieved.

[0070] The weight-average molecular weight M w of the polymer or of the polymers of the polymer component is preferably in the range of 200,000 ≤ M w ≤ 3,000,000 g / mol. Unless otherwise stated, data on the weight-average molecular weight M w or the number-average molecular weight M n of polymers (or oligomers) in the present application refer in each case to the determination by gel permeation chromatography (GPC) under the following conditions. The eluent used in each case was THF with 0.1 vol.% trifluoroacetic acid. The measurement was carried out at 25 °C. The precolumn used was PSS-SDV, 5 µ, 10 3 < Å, ID 8.0 mm x 50 mm. PSS-SDV columns with 5 µ, 10 3 < Å, 10 5 < Å, and 10 6 < Å, each with an ID of 8.0 mm x 300 mm, were used for separation. The sample concentration was 4 g / L, and the flow rate was 1.0 ml per minute. Measurements were made against PMMA standards (µ = µm; 1 Å = 10 -10 < m).

[0071] The polymers of the polymer component are typically based to at least 15% by weight, such as 15 to 99% by weight, on one or more alkyl (meth)acrylate monomers, i.e., alkyl (meth)acrylic acid esters, wherein the alkyl radical, i.e., the alcohol component, has, in particular, 1 to 25 carbon atoms. Typically, the acrylate monomers used are as defined in claim 1. According to the invention, other relatively polar polymers, such as, for example, specially modified polyesters, polyurethanes, or polyurethane acrylates, can also be used as the polymer component as an alternative to or in addition to the poly(meth)acrylate.

[0072] The hydrocarbon radical of the alcohol component of the acrylate monomers preferably used according to the invention can be branched or unbranched or cyclic, saturated or unsaturated, aliphatic or aromatic, substituted or unsubstituted.

[0073] The hydrocarbon radical of the alcohol component of the acrylate monomers can in particular be an alkyl or alkenyl group having 1 to 14 carbon atoms, hydrocarbon radicals having 4 to 10 carbon atoms are particularly advantageous. Advantageous examples of acrylate monomers are n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, n-nonyl acrylate, lauryl acrylate, stearyl acrylate, behenyl acrylate, and their branched isomers, such as isobutyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 2-cyanoethyl acrylate, 1,2-diphenylethyl methacrylate, diphenylmethyl methacrylate, ortho-chlorobenzyl methacrylate, p-bromophenyl methacrylate and 3,5-Dimethyladamantyl acrylate.

[0074] The pressure-sensitive adhesive polymer electrolyte described in this document is also outstandingly suitable for use as an optically clear adhesive in display units of electronic devices (displays), in particular as a pressure-sensitive adhesive polymer electrolyte in adhesive tapes, and most particularly as a pressure-sensitive adhesive polymer electrolyte in double-sided adhesive tapes. The double-sided adhesive tape can be provided with an optically transparent carrier or it can be a carrierless double-sided adhesive tape. It is particularly preferred that no carrier is used, as this readily enables ion exchange in the electrolyte. If an optically transparent carrier is used, it must be permeable to the ions. This makes them suitable for electrochromic applications for windows of all kinds. Such carriers also include transparent papers made from modified cellulose fibers.

[0075] A high transmission value of the pressure-sensitive electrolyte at 550 nm is particularly advantageous. This ensures the necessary light transmission in this range. The Lab color space is a color space that covers the range of perceivable colors (see DIN EN ISO 11664-4). It has been found that the b* value, in particular, correlates with the perceivable degree of yellowing. b* values ​​greater than 1 are perceived as yellowing. Accordingly, according to the invention, b* is optimally in the range of -1 < b* <1. However, the value range of -6 < b* < 6 can also be considered good. According to ASTM D1003-00, the term "haze" describes the scattering of light by a body, expressed as the percentage of the light that is deflected at more than a specified angle.A haze of less than 5% is preferred, and a haze of <2%, such as <1%, is particularly preferred, in order not to impair visibility through the electrolyte layer according to the invention. Surprisingly, it has been shown that such clarity can be achieved with the pressure-sensitively adhesive electrolyte layers according to the invention, despite high conducting salt contents. Conductive salts:

[0076] Common conducting salts such as lithium hexafluorophosphate, usually used at a concentration of 1 mol / l, can also be used in the pressure-sensitive electrolytes according to the invention. LiClO 4 is also soluble in many solvents and polymers at high concentrations and possesses large anions and a high dissociation constant. 0.75 mol / l LiClO 4 can be dissolved in 10 wt.% plasticized PMMA. Lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) is particularly advantageous with regard to its moisture resistance. In principle, however, other cations such as Na +< , K +< , Cs +< , Rb +< , Ag +< , Cu +< , Cu 2+< , Mg 2+< and other anions such as Cl -< , Br -< , I -< , ClO 4 -< , SCN -< , AsF 6 -< , CF 3 SO 3 -< , CH 3 CO 2 -< , bis(oxalato)borate (BOB), BF 4 -< , [PF 3 (CF 2 CF 3 ) 3 ] -< (FAP), trifluoromethylbenzimidazole anion, difluorooxalatoborate (FOB) and C(CF 3 SO 2 ) 3 -< can be used pure or in a mixture. Additives:

[0077] The addition of nanoparticles to prevent the crystallization tendency of polymer electrolytes, especially their polymer, can be advantageous. Suitable fillers, some of which increase the dielectric constant of the polymer composite, such as barium titanate, include CeO 2 , Er 2 O 3 , ZnO, or titanium dioxide. They improve the ion dissociation of the conductive salt and provide diffusion channels for the ions. Other additives, for example, to stabilize cycling stability, such as cyclohexylbenzene, t-amylbenzene, adiponitrile, 2-propynylmethanesulfonate, 1,3-propanesulfone, or vinylene carbonate, can also be added.

[0078] To prevent yellowing of conductive coatings such as indium tin oxide or other active materials, the electrolyte can be treated with UV protection additives that absorb not only the UV-A and UV-B ranges, but particularly the UV-C range. Suitable examples for this purpose include 2-(2H-benzotriazol-2-yl) derivatives. However, ethanediamide derivatives and piperidine derivatives can also be used. In a highly preferred procedure, at least one [3,5-bis-(1,1-dimethylethyl-4-hydroxyphenyl)methyl]alkylmalonate derivative is also added to the acrylic adhesive of the pressure-sensitive adhesive layer. Proportions between 0.2 and 4.0 wt.% absorber have proven to be advantageous, whereby very thin layers in the range of less than 30 µm should have higher proportions of absorber between 2 - 4 wt.%, while thick electrolyte layers around 200 µm thick can manage with 0.3 wt.% absorber.

[0079] Furthermore, to optimize the adhesive properties, resins can be added to the pressure-sensitive adhesive polymer electrolytes of the invention, i.e., pressure-sensitive adhesives. Resins within the meaning of this invention are typically considered to be oligomeric and polymeric compounds having a number-average molecular weight M n of not more than 10,000 g / mol; these are not counted as the polymer component. Tackifying resins (adhesive strength-increasing resins, i.e., adhesive resins) that can be added include, without exception, all previously known adhesive resins described in the literature. Examples include pinene resins, indene resins, and rosin resins, their disproportionated, hydrogenated, polymerized, and esterified derivatives and salts, aliphatic and aromatic hydrocarbon resins, terpene resins, and terpene-phenolic resins, as well as C 5 to C 9 and other hydrocarbon resins.Any combination of these and other resins can be used to tailor the properties of the resulting adhesive. In general, any resin compatible with the corresponding base polymer (soluble) can be used, including, in particular, all aliphatic, aromatic, and alkylaromatic hydrocarbon resins, hydrocarbon resins based on pure monomers, hydrogenated hydrocarbon resins, functional hydrocarbon resins, and natural resins.

[0080] The presence of adhesive resins can be dispensed with in the acrylate-based pressure-sensitive adhesive polymer electrolyte typically used according to the invention, so that an excellent embodiment variant is the pressure-sensitive adhesive electrolyte according to the invention in which no resins are added to the pressure-sensitive adhesive. Such additives often have adverse effects when used for optical bonding. The resins used according to the prior art as adhesive resins for acrylic pressure-sensitive adhesives are usually polar in nature in order to achieve compatibility with the polyacrylate matrix. This usually leads to the use of aromatic adhesive resins, which turn yellow upon prolonged storage or upon exposure to light. Product design:

[0081] The pressure-sensitive adhesive tape according to the invention can preferably be a pressure-sensitively adhesive electrolyte with double-sided adhesive. The pressure-sensitively adhesive electrolyte can have one or more optically transparent carrier layers, wherein at least one of the outer adhesive layers, preferably in the case of double-sided carrier-containing adhesive tapes, both outer adhesive layers, are based on the polymer component described above and are in particular identical. In the case of a double-sided adhesive tape, the middle carrier layer is also at least as ionically conductive as the surrounding layers of the pressure-sensitively adhesive electrolyte.

[0082] Particularly advantageous are double-sided, carrier-free adhesive tapes, especially those adhesive tapes which are formed exclusively from the layer of an ion-conductive acrylic pressure-sensitive adhesive composition as described according to the invention.

[0083] One possible embodiment of the pressure-sensitive adhesive tape can also be provided as a single-sided adhesive tape, wherein in this embodiment, the electrolyte according to the invention is already bonded to a half-cell and is available as roll material. In this case, the layer structure includes either the components film carrier - conductive coating - cathode material - electrolyte - liner (optional) or the components film carrier - conductive coating - anode material - electrolyte - liner (optional) in the order shown. By providing a half-cell as a semi-finished product, cell production can be delocalized, particularly because the semi-finished product is stable over long transport routes.

[0084] The additive-containing polyacrylate available as described above is applied to one or both sides of an optically transparent carrier to produce a pressure-sensitive adhesive layer. A permanent carrier can be used, which remains in the adhesive tape structure even during use. However, carrier-free, particularly single-layer adhesive tapes are particularly advantageously produced. In a very advantageous embodiment, these consist solely of the pressure-sensitive adhesive layer (so-called transfer adhesive tapes) and are provided with a temporary carrier on one or both sides for prior handling, packaging, and commercialization, in particular wound into a roll.

[0085] To produce such transfer adhesive tapes, the pressure-sensitive polyacrylate electrolyte available as described above is advantageously coated onto a temporary carrier (made of, in particular, anti-adhesive and / or anti-adhesive materials, so-called cover materials, release materials, or (release) liners, such as siliconized papers, films, or the like) in the desired layer thickness. In principle, all release materials suitable for polyacrylate pressure-sensitive adhesives can be used. Release liners with a PET carrier core are particularly preferred.

[0086] Adhesive tapes with two (pressure-sensitive) adhesive layers of different types can also be produced, at least one of which is a pressure-sensitive adhesive layer (according to the invention) as described in this document. The pressure-sensitive adhesive layers can be directly adjacent to one another (two-layer adhesive tape); one or more additional layers, such as carrier layers or the like (multilayer structure), can optionally be provided between the two pressure-sensitive adhesive layers. Process for producing the polymer electrolyte:

[0087] In principle, solvent polymerization and solvent coating, UV polymerization and extrusion are particularly suitable as possible processes for producing pressure-sensitive adhesives according to the invention.

[0088] In solvent polymerization, the polymer is prepared in solvent, and additives are added either before or during polymerization, or after polymerization of the polymer solution. The polymer solution is then coated onto a sheet of release paper, and the solvent is partially or completely removed by drying.

[0089] During extrusion, polymerization also takes place in the solvent. Some or all of the additives can be added during or after polymerization. The polymer solution is then concentrated to obtain a low-solvent or solvent-free, highly viscous but non-crosslinked polymer melt, which can then be further provided with additives or directly coated onto a release paper or other substrate by extrusion through a slot die or by forming in a calender. Concentration can take place, for example, in an extruder. Further additives such as conductive salts and / or crosslinkers can be added to the polymer melt in the same extruder or in additional extruders connected in series. After coating, crosslinking takes place, for example, thermally or photoinduced, i.e. light-induced.

[0090] UV polymerization has proven particularly advantageous. During extensive investigations, it became apparent that, among other monomers, 2-cyanoethyl acrylate, which is particularly well-suited for the electrolytes according to the invention, tends to gel very quickly due to the low purities available on the market. This monomer contains a high proportion of undesirable diacrylates, which lead to undesired crosslinking or gelling. During bulk UV polymerization, this effect does not negatively impact the visual appearance of the electrolyte layer. The crosslinking and cohesion-enhancing effect can even be advantageously exploited for the electrolytes according to the invention. Thus, the additional addition of photoactive crosslinkers or multifunctional acrylates such as hexanediol diacrylate (HDDA) can be reduced or even completely avoided.2-Cyanoethyl acrylate, like 2-(2-ethoxyethoxy)ethyl acrylate, is thus preferably used in the preparation of the polymer electrolyte according to the invention.

[0091] The invention is explained in more detail below with the aid of a few examples. Particularly advantageous embodiments of the invention are explained in more detail using the examples described below, without intending to unnecessarily limit the invention. Examples:

[0092] The following raw materials were used in the examples: (a) Acrylate monomers: 2-Ethylhexyl acrylate (EHA) from BASF, which, when homopolymerized, has a T g according to Test C of -50 °C. 2-(2-Ethoxyethoxy)ethyl acrylate from Polysciences, which, when homopolymerized, has a T g according to Test C of -70 °C. 2-Cyanoethyl acrylate (2-CEA, Bimax designation BX-2-CEA) from Bimax Specialty Polymers, which, when homopolymerized, has a T g according to Test C of 4 °C. Glycidyl methacrylate from Mitsubishi Gas Chemical Company, which, when homopolymerized, has a T g according to Test C of 41 °C. (b) Thermal initiators: Vazo 67TM: 2,2'Azobis(2-methylbutyronitrile) from DuPont (c) Photoinitiators: Benzoin ethyl ether from Sigma-Aldrich Lauroyl peroxide (LPO) (C 24 H 46 O 4 ) from Sigma-Aldrich, also suitable as thermal initiator (d) Radical scavenger: Perkadox 16TM: Bis-(4-tert.-butylcyclohexyl) peroxydicarbonate from Akzo Nobel (e) Crosslinker: Hexanediol diacrylate (HDDA) from Polysciences Trimethylolpropane trimethacrylate (TMPTMA) (C 18 H 26 O 6 ) from Polysciences 2-(4-Methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (MTT) from TCI Deutschland GmbH (f) Conducting salts: Lithium hexafluorophosphate (LiPF 6 ) from Sigma-Aldrich Lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) from Sigma-Aldrich Lithium tetrafluoroborate (LiTFB) from Sigma-Aldrich (g) Solvent: Diethyl ether from Sigma-Aldrich, boiling point (1013 mbar): 35 °C Ethyl acetate from Sigma-Aldrich, boiling point (1013 mbar): 77 °C (h) Plasticizer: Ethylene carbonate (EC) from Sigma-Aldrich, boiling point (1013 mbar): no boiling point, but decomposition at 248 °C (ieDecomposition temperature = 248 °C) Diethyl carbonate (DEC) from Sigma-Aldrich, boiling point (1013 mbar): 126 to 128 °C Ethyl methyl carbonate (EMC) from Sigma-Aldrich, boiling point (1013 mbar): 107 °C (i) Additives: Acetylcysteine ​​(chain regulator) from Sigma-Aldrich Zinc chloride (catalyst) from Sigma-Aldrich.

[0093] The following Example 1 demonstrates the preparation of a pressure-sensitively adhesive polyelectrolyte according to the invention by solvent polymerization. The components used add up to 100 wt. %, excluding solvent. Example 1 - Solvent polymerization:

[0094] To produce a cyanoethyl acrylate-based pressure-sensitive adhesive polymer according to the invention, 302 g of a mixture of 3.53 wt.% glycidyl methacrylate, 35.29 wt.% 2-cyanoethyl acrylate, and 31.76 wt.% 2-ethylhexyl acrylate, 0.47 wt.% acetylcysteine, 10.59 wt.% EC, and 10.59 wt.% DEC in 300 g of ethyl acetate were initially charged into a 2 L glass reactor. After degassing the reaction solution by passing nitrogen through it for 45 minutes while stirring, it was heated to 58°C, and 0.2 g (0.05 wt.%) of 2,2'azobis(2-methylbutyronitrile) (Vazo 67™ from DuPont) was added as a radical initiator. After the addition, the reaction solution was heated to 75 °C, and the polymerization reaction was carried out at this temperature. One hour after the start of the reaction, an additional 0.2 g (0.05 wt%) of 2,2'azobis(2-methylbutyronitrile) was added to the reaction mixture.Four hours after the start of the reaction, the reaction mixture was diluted with 100 g of ethyl acetate. A further 100 g of ethyl acetate was added after a further four hours (i.e. eight hours after the start of the reaction). To reduce the remaining radical initiator in the reaction mixture, 0.6 g (0.14 wt.%) of bis(4-tert.-butylcyclohexanyl) peroxydicarbonate (Perkadox 16™ from Akzo Nobel) was added to the reaction mixture eight and ten hours after the start of the reaction. Twenty-four hours after the start of the reaction, the polymerization reaction was terminated by cooling the reaction mixture to room temperature (23 °C). To produce an adhesive from the resulting polymer, the reaction product was mixed with 15 g of a 10 wt.% solution of zinc chloride in diethyl ether, corresponding to 0.35 wt.% zinc chloride. In addition, 7.06 wt.% of the conducting salt was added.-% LiTFSI was added, and the mixture was spread onto a release film with a comma knife (dry thickness: 30 µm) and dried (40 m channel with 8 drying zones at 30, 40, 40, 60, 90, 120, 120, and 20 °C and a web speed of 15 m / min). A small portion of the plasticizer (EC or DEC) evaporates in the dryer, although more than 80 wt.% of the plasticizer remains after drying.

[0095] The following examples show the preparation of a pressure-sensitive adhesive polyelectrolyte according to the invention by means of UV polymerization (Examples 2 to 9) and of a comparative electrolyte also prepared by UV polymerization (Comparative Example 10). Examples 2 to 9 - UV polymerization:

[0096] The electrolytes according to the invention, which were preferably polymerized without solvents, were prepared using the following sequential steps: a) prepolymer preparation, i.e., syrup preparation; b) formulation of the prepolymer, i.e., incorporation of the prepolymer or syrup into the final mixture; and c) coating and curing of the final mixture, where curing refers to the polymerization or crosslinking. All quantities refer to the final formulation after process steps a) and b). See the following details: Example 2:

[0097] In the following, the individual steps of the production of the pressure-sensitive adhesive polymer electrolyte are described using Example 2, including the respective quantities: Step a) A mixture of 25 wt% 2-ethylhexyl acrylate (2-EHA), 35 wt% 2-(2-ethoxyethoxy)ethyl acrylate, and 0.2 wt% benzoin ethyl ether was irradiated in a stirred-tank reactor using a Philips Actinic BL TL-D 15W / 10 1SL / 25 UV lamp (UV-A radiation 350-400 nm, distance from the surface of the reaction mixture: 20 cm) to a conversion of 10%, monitored with a Mettler Toledo ReactlR 702L TEMCT. The reaction temperature was maintained at 20 °C during the reaction. The reaction was terminated upon reaching the target conversion by switching off the lamp and bubbling in oxygen. Step b) The reaction mixture from step a) ("syrup") was mixed with 29.55 wt% 2-cyanoethyl acrylate (2-CEA), a further 0.1 wt% benzoin ethyl ether, 0.15 wt% 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine (MTT) and 10 wt% lithium hexafluorophosphate.Step c) Using a nozzle coating technique, a 30 µm thick layer was applied to a siliconized liner (75 µm PET) and covered with a second 75 µm PET liner. In the absence of oxygen, the mixture between the two liners was irradiated with the same UV-A radiation used to produce the syrup. Curing was carried out at a dose of 80 mWs / cm² using 56 Philips Actinic BL TL-D 15W / 10 1SL / 25 lamps, with a residence time in the irradiation channel of 3.5 minutes (i.e., 210 seconds). Examples 3 to 9:

[0098] The pressure-sensitive polyelectrolytes of Examples 3 to 9 were prepared as described above for the polyelectrolyte from Example 2, varying the type and amount of the components used as indicated in Table 1 (the components each add up to 100 wt%). Any plasticizers used (EC, DEC) are still completely present in the product after curing. Comparative Example 10 - UV polymerization:

[0099] The electrolyte from Comparative Example 10 was also produced by UV polymerization. However, prepolymerization step a) was omitted. In step b), the components trimethylolpropane trimethacrylate (TMPTMA), lauroyl peroxide, lithium hexafluorophosphate, ethylene carbonate, diethyl carbonate, and ethyl methyl carbonate were mixed. In step c), a 30 µm thick layer was applied to a siliconized liner (75 µm PET) and covered with a second 75 µm PET liner. The mixture between the two liners was irradiated with UV-A radiation in the absence of oxygen. Curing was performed at a dose of 80 mWs / cm² using 56 Philips Actinic BL TL-D 15W / 10 1SL / 25 lamps, with a dwell time in the irradiation channel of 3.5 minutes, or 210 seconds (instead of irradiation, curing can also be performed thermally at 80 °C for 1800 seconds). The type and quantity of the components are also listed in Table 1. Table 1: Components of polymer electrolyte preparation and curing conditions. Example Components Step a) Added components step b) Dose (time) in step c) 2 25% by weight 2-EHA, 35% by weight 2-(2-ethoxyethoxy)ethyl acrylate, 0.2% by weight benzoin ethyl ether 31.55% by weight 2-CEA, 0.1% by weight benzoin ethyl ether, 0.15% by weight MTT, 8% by weight LiPF 6 80 mWs / cm 2 < (210 s) 3 20% by weight 2-EHA, 30% by weight 2-(2-ethoxyethoxy)ethyl acrylate, 0.2% by weight benzoin ethyl ether 19.55% by weight 2-CEA, 0.1% by weight benzoin ethyl ether, 0.15% by weight MTT, 10% by weight LiPF 6, 10% by weight EC, 10% by weight DEC 80 mWs / cm 2 < (210 s) 4 25% by weight 2-EHA, 35% by weight 2-(2-ethoxyethoxy)ethyl acrylate, 0.2% by weight benzoin ethyl ether 31.7% by weight 2-CEA, 0.1% by weight benzoin ethyl ether, 8% by weight LiPF 6 80 mWs / cm 2 < (210 s) 5 20 wt.-% 2-EHA, 30 wt.-% 2-(2-ethoxyethoxy)ethyl acrylate, 0.2 wt.-% benzoin ethyl ether 19.7 wt.% 2-CEA, 0.1 wt.% benzoin ethyl ether, 10 wt.% LiPF 6 , 10 wt.% EC, 10 wt.% DEC 80 mWs / cm 2< (210 s) 6 54.55 wt.% 2-EHA, 40 wt.% 2-(2-ethoxyethoxy)-ethyl acrylate, 0.2 wt.% benzoin ethyl ether 0.1 wt.% benzoin ethyl ether, 0.15 wt.% MTT, 5 wt.% LiPF 6 80 mWs / cm 2< (210 s) 7 25 wt.-% 2-EHA, 35 wt.-% 2-(2-ethoxyethoxy)ethyl acrylate, 0.2 wt.-% benzoin ethyl ether 31.55 wt.% 2-CEA, 0.1 wt.% benzoin ethyl ether, 0.15 wt.% MTT, 8 wt.% LiTFSI 80 mWs / cm 2< (210 s) 8 25 wt.-% 2-EHA, 35 wt.-% 2-(2-ethoxyethoxy)ethyl acrylate, 0.2 wt.-% benzoin ethyl ether 31.55 wt.% 2-CEA, 0.1 wt.% benzoin ethyl ether, 0.15 wt.% MTT, 8 wt.% LiTFB 80 mWs / cm 2< (210 s) 9 18.15 wt.% 2-EHA, 30 wt.% 2-(2-ethoxyethoxy)-ethyl acrylate, 0.2 wt.% benzoin ethyl ether 19.55 wt.% 2-CEA, 0.1 wt.% benzoin ethyl ether, 2 wt.% HDDA, 10 wt.% LiPF 6 , 10 wt.% EC, 10 wt.% DEC 80 mWs / cm 2< (210 s) 10 no prepolymerization 2 wt.% TMPTMA, 1 wt.% LPO, 97 wt.% 1M LiPF 6 in EC:EMC:DEC (weight ratio 1:1:1) 80 mWs / cm 2< (210 s) (or 80°C (1800 s)) Results and discussion:

[0100] Table 2 shows the property profile of the polymer electrolytes produced from Examples 1 to 10. The ionic conductivity, the glass transition temperature (T g ), the adhesive strength (KK) to steel, the shear resistance (Holding Power, HP), the heat resistance (Shear Adhesion Failure Temperature, SAFT), the haze, the transmittance and the color parameter b* are given as determined in the test method section. Table 2: Property profile of the polymer electrolytes. Example Ionic conductivity [S / cm] Tg [°C] KK steel [N / cm] HP [min.] JUICE [°C] Haze [%] Transmission [%] b* 1 1,5*10 -5< -28 4,5 10000 >200 2,0 98 2,6 2 8,8*10 -5< -45 4,2 10000 >200 1,1 98 1,5 3 2,3*10 -3< -52 3,9 8668 135 1,3 98 1,1 4 1,2*10 -4< -53 4,6 9567 161 1,1 99 1,2 5 4,2*10 -3< -51 3,6 4571 144 1,4 98 0,7 6 9,2*10 -6< -65 3,1 2554 112 1,3 97 1,2 7 2,9*10 -5< -45 3,8 10000 192 1,3 98 1,8 8 1,3*10 -5< -45 3,4 10000 >200 1,5 98 1,1 9 7,3*10 -3< -51 2,4 10000 138 1,1 98 0,7 10 1,1*10 -2< 27 0,1 n / a n / a 14,7 95 2,1

[0101] Example 2 shows a transparent polymer electrolyte that can absorb a high proportion of conductive salt. Due to the high polarity of over 30 wt.% polymerized 2-CEA, the solubility is high, and because it is added in the second polymerization step to the already formed sheet, gel formation does not impair the appearance. Therefore, regulatory additives such as RAFT regulators are not necessary. Due to impurities in the raw material, 2-CEA has a strong tendency to gel and can only be used in small concentrations in the processes normally used. Example 3 also contains low-molecular-weight plasticizers. Despite this, the cohesion is still satisfactory at 8668 minutes. The plasticizer content has a positive effect on ion mobility and increases conductivity.

[0102] Example 4 shows that even without the addition of the branching crosslinker MTT, sufficient cohesion can be achieved with a high proportion of 2-CEA, especially when no other regulators are used. Here, too, the ionic conductivity is somewhat better than with the use of MTT. However, Example 5 exhibits low cohesion when polymerized without the branching crosslinker, with a high plasticizer content, and with a lower 2-CEA content.

[0103] Example 6 contains a high proportion of nonpolar 2-EHA and can therefore dissolve only a small amount of conducting salt. The ionic conductivity is correspondingly low.

[0104] Examples 7 and 8 use the conducting salts LiTSFI and LiTFB, where the conductivity still assumes a sufficient value, but below that of LiPF 6 .

[0105] Example 9 shows that good cohesion and conductivity can be achieved with the crosslinking monomer HDDA despite the high plasticizer content. The low b* value is particularly striking.

[0106] Example 10 shows an electrolyte with high conductivity but low dimensional stability and adhesive strength. Due to a lack of cohesion, neither shear strength nor the SAFT test were measurable, as the sample failed while hanging before the measurement. Furthermore, the polymer network was incompatible with the conductive salt and plasticizer, resulting in an inhomogeneous porous structure with a very high haze of 14.7%. Such high haze values ​​are intolerable for optically transparent cells such as electrochromic systems. Test methods:

[0107] Unless otherwise stated, all measurements were conducted at 23 °C and 50% relative humidity. Unless otherwise stated, measurements of the pressure-sensitive adhesive polymer electrolyte were also performed on a 30 µm thick layer of the polymer electrolyte, meaning that the measurement results for the pressure-sensitive adhesive polymer electrolyte typically refer to a layer thickness of 30 µm.

[0108] The mechanical and adhesive data were determined as follows: Test A - Adhesive strength

[0109] The adhesive strength of the samples in the form of an adhesive tape with a thickness of 30 µm on a glass substrate (peel strength) was determined using a method according to PSTC 1. For this purpose, a strip of the surface element with a width of 2 cm was applied to a glass plate in such a way that only a free end section of the strip was not in contact with the surface of the glass plate. The area of ​​the adhesive strip in contact with the glass substrate was pressed against the glass substrate using a roller with a mass of 2 kg by rolling over it three times, with each roll comprising two roller passes, each applying load in opposite feed directions. The temporary covering material was then removed by hand.

[0110] For the actual bond strength measurement, the glass plate with the surface element attached in this way was fixed in place. The surface element was attached by its free end to a tensile testing machine and, 10 minutes after bonding (measurement of the immediate bond strength), was peeled off using the tensile testing machine at a peel angle of 180° and a feed rate of 300 mm / min. The maximum force at which no detachment of the bond was observed corresponds to the bond strength on the corresponding substrate; this is given in N / cm. The measured value (in N / cm) was the average of three individual measurements. Test B - Ionic Conductivity

[0111] The ionic conductivity of lithium ions was measured using EIS (electrochemical impedance spectroscopy) by calculating the ionic conductivity from the Nyquist plot fit of a suitable equivalent circuit. A Metrohm Autolab PGSTAT204 with FRA32M module and an Autolab Microcell HC apparatus with a TSC battery cell attached was used for the measurement. A sample with a diameter of 10 mm was applied between the electrodes. To calculate the cell constant, the sample thickness was measured beforehand using a Wolf DM2010 thickness gauge. The measurement was performed at a frequency of 100 kHz to 0.1 Hz with an AC voltage of 10 mV RMS. The evaluation was performed using the software NOVA2. The measurement temperature was 25°C. Test C - Glass transition temperature T g

[0112] Glass transition points – synonymously referred to as glass transition temperatures – are given as the result of measurements using dynamic scanning calorimetry (DSC) according to DIN 53 765, particularly sections 7.1 and 8.1, but with uniform heating and cooling rates of 10 K / min in all heating and cooling steps (see DIN 53 765; section 7.1; note 1). The sample weight was 20 mg. Test D - Haze

[0113] 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. For sample preparation, a 30 µm transfer tape of the pressure-sensitive sample was applied bubble-free to a polycarbonate film (125 µm Lexan 8010 with freshly coated surfaces; haze of this film alone was 0.09%). The procedure for measuring the haze value is described in ASTM D 1003. 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 value was measured using a Hazegard Plus from Byk-Gardner GmbH. The samples were irradiated vertically and the transmitted light was measured photoelectrically in an integrating sphere (Ulbricht sphere).The spectral sensitivity is adapted to the CIE standard spectral value function Y under standard illuminant C. Test E - Transmission

[0114] For sample preparation, a 30 µm transfer tape of the pressure-sensitive sample was applied bubble-free to a polycarbonate film (125 µm Lexan 8010 with freshly coated surfaces; haze of this film alone was 0.09%). The transmittance and haze values ​​were measured using a Hazegard Plus from Byk Gardner. The samples were irradiated vertically, and the transmitted light was measured photoelectrically in an integrating sphere (Ulbricht sphere). The spectral sensitivity is adjusted to the CIE standard spectral value function Y under standard illuminant C. The transmittance was measured in the wavelength range from 190 to 900 nm using a Uvikon 923 from Biotek Kontron. The absolute transmittance is given as the value at 550 nm in %. Prior to the measurement, an empty channel measurement was performed over the entire wavelength range. Test F - Color Characteristics

[0115] The procedure was carried out in accordance with DIN EN ISO 11664, and the color characteristics in three-dimensional space, spanned by the three color parameters L*, a*, and b*, were examined according to CIELAB. A BYK Gardener Spectro Guide measuring instrument equipped with a D / 65° lamp was used for this purpose. Within the CIELAB system, L* indicates the gray value (0 = black, 100 = white), a* the color axis from green to red (-120 = green, +120 = red), and b* the color axis from blue to yellow (-120 = blue, +120 = yellow). The positive value range for b* thus indicates, for example, the intensity of the yellow color component. A white ceramic tile with a b* of +1.05 served as the reference. This tile also served as the sample holder onto which the adhesive layer to be tested was laminated. The color measurement of the adhesive to be tested, i.e. pressure-sensitive sample, was carried out on the respective pure adhesive layer, unless otherwise stated in 30 µm layer thickness.The values ​​for L*, a*, and b* of the adhesive layer specified in the application have already been adjusted for the values ​​of the substrate tile. For example, b* of the adhesive layer, as specified in the application, is the difference between the color value determination for the adhesive film sample applied to the substrate tile and the color value determination of the pure substrate tile. Test G - Shear Adhesion Failure Temperature (SAFT), heat resistance

[0116] This test is used to quickly test the shear strength of adhesive tapes under temperature stress. An adhesive tape (length approx. 50 mm, width 10 mm) cut from the respective sample, i.e. a pressure-sensitive adhesive sample with a layer thickness of 30 µm, was bonded to a steel test plate cleaned with acetone so that the steel plate overlapped the adhesive tape on the right and left and the adhesive tape overlapped the test plate by 2 mm at the upper edge. The bonded area of ​​the sample was height x width = 13 mm x 10 mm. The bonded area was then rolled over six times with a 2 kg steel roller at a speed of 10 m / min. The adhesive tape was reinforced flush with a sturdy adhesive strip, which served as a support for the displacement sensor. The sample was suspended vertically using the test plate.

[0117] The sample to be measured was loaded with a 50 g weight at its lower end. The steel test plate with the bonded sample was heated from 25 °C at a rate of 9 °C per minute to a final temperature of 200 °C. The slip distance of the sample ("SAFT shear distance") was measured using a displacement sensor as a function of temperature and time. The maximum slip distance is set to 1000 µm; if this limit is exceeded, the test is aborted. Test H - Shear resistance

[0118] A 13 mm wide strip of the respective sample (adhesive tape in the form of a layer of the pressure-sensitive adhesive sample with a thickness of 30 µm) was applied to a steel plate. The steel plates were previously wiped four times with acetone and left to air for at least 1 minute and a maximum of 10 minutes. The application area was 20 mm x 13 mm (length x width). The adhesive tape was then pressed onto the steel support four times using a roller weighing 2 kg. A 1 kg weight was attached to the adhesive tape. The measured shear strength times are given in minutes and correspond to the average of three measurements. The measurements were carried out at 40 °C in an oven. The test was terminated after a maximum of 10,000 min. Test I - Electrochemical Stability

[0119] To determine electrochemical stability, i.e. oxidative stability, linear sweep voltammetry (LSV) against a platinum counter electrode was used at a sweep rate of 1 mV / s. A range of -0.1 V to 6.5 V against Li / Li +< was measured, with platinum used as the working electrode in the anodic region and copper as the working electrode in the cathodic region. When plotting the current density [mA / cm 2< ] against the potential against Li / Li +< [V], the stability window was defined as a maximum deviation in the current density of 0.25 mA / cm 2<. A Metrohm Autolab PGSTAT204 was used for the measurement, and the NOVA2 software was used for evaluation. Test J - relative permittivity ε r

[0120] The relative permittivity was measured at a temperature of 23 °C in a plate capacitor with a variable measuring gap, the electrode plates of which had a diameter of 60 mm. For the measurement, a sample of homogeneous thickness was inserted into the measuring gap as a dielectric without any air inclusions and brought into full-surface and gap-free contact with the two electrode plates. The resulting distance between the electrode plates (which should ideally be identical to the thickness of the sample to be tested) was determined using a caliper. In addition, a blank measurement was carried out with the same distance between the electrode plates. For this purpose, the material to be tested was removed, so that air was used as the dielectric of known permittivity for the blank measurement. For both the measurement and the blank measurement, the capacitance of the test setup was determined for a measuring frequency of 1 kHz using an LCR meter (type: GWInstec LCR 821).The relative permittivity of the sample material was determined by comparing the two measured capacitances; the calculation was carried out according to conventional determination methods, such as those specified in the ASTM D150 standard.

Claims

1. A pressure-sensitive adhesive polymer electrolyte with a peel adhesion in accordance with test A, described in the description, of more than 1 N / cm and an ionic conductivity in accordance with test B, described in the description, of more than 10-6(ohm*cm)-1, produced by polymerizing a mixture which comprises at least the following components: • 5 - 60% by weight, preferably 10 - 50% by weight, in particular 15 - 30% by weight, of acrylate monomer from the group formed by (meth)acrylic acid esters containing 4 - 15 carbon atoms, wherein the number of carbon atoms is in each case with respect to the whole molecule, i.e. the acid component and alcohol component together, and the acrylate monomer would, as a homopolymer, have a Tg in accordance with test C, described in the description, of less than -30°C, • 10 - 80% by weight, preferably 35 - 75% by weight, in particular 50 - 70% by weight, of acrylate monomer from the group formed by (meth)acrylic acid esters containing 4 - 25 carbon atoms and containing at least one heteroatom, wherein the number of carbon atoms is in each case with respect to the whole molecule, i.e. the acid component and alcohol component together, the heteroatom in addition to the two O atoms being present in the ester functional group and the acrylate monomer would, as a homopolymer, have a Tg in accordance with test C, described in the description, of less than 100°C, • 0.05 - 10% by weight, preferably 0.1 - 2% by weight, of initiator, • 2 - 13% by weight, preferably 3 - 10% by weight, in particular 4 - 8% by weight, of conducting salt, • optionally, plasticizer, preferably in a proportion of 5 to 50% by weight, • and optionally, solvent which, following polymerization, is typically at least partially removed, such as, for example, substantially completely removed, wherein optionally, at least a proportion, such as the entirety, for example, of one or more of the components are added only during or after the polymerization.

2. The pressure-sensitive adhesive polymer electrolyte as claimed in claim 1, characterized in that the initiator is a thermal initiator and / or a photoinitiator, preferably a photoinitiator, wherein in each case, the initiator preferably initiates a radical polymerization.

3. The pressure-sensitive adhesive polymer electrolyte as claimed in claim 1 or claim 2, characterized in that the polymerization is a UV polymerization, preferably a radical UV polymerization.

4. The pressure-sensitive adhesive polymer electrolyte as claimed in one of the preceding claims, characterized in that the mixture further comprises crosslinkers, preferably in a proportion of 0.05 to 5% by weight, more preferably from 0.1 to 3% by weight, such as, for example, from 0.15 to 2% by weight.

5. The pressure-sensitive adhesive polymer electrolyte as claimed in one of the preceding claims, characterized by a haze in accordance with test D of less than 10%, preferably less than 5% and in particular less than 2%, such as, for example, less than 1%.

6. The pressure-sensitive adhesive polymer electrolyte as claimed in one of the preceding claims, characterized by a transmission in accordance with test E of more than 75%, preferably more than 85% and in particular more than 90%, such as, for example, more than 95%.

7. The pressure-sensitive adhesive polymer electrolyte as claimed in one of the preceding claims, characterized by a colour parameter b* in accordance with test F of -6 < b* < 6, preferably -2 < b* < 2 and in particular -1 < b* < 1.

8. The pressure-sensitive adhesive polymer electrolyte as claimed in one of the preceding claims, characterized by a colour parameter a* in accordance with test F of -6 < a* < 6, preferably -2 < a* < 2 and in particular -1 < a* < 1.

9. The pressure-sensitive adhesive polymer electrolyte as claimed in one of the preceding claims, characterized by a thermal resistance in accordance with test G of more than 60°C, preferably more than 100°C, more preferably more than 150°C and in particular more than 200°C.

10. The pressure-sensitive adhesive polymer electrolyte as claimed in one of the preceding claims, characterized by a holding power in accordance with test H of more than 10 min, preferably more than 1000 min and in particular at least 10000 min.

11. A pressure-sensitive adhesive tape containing at least one layer of a pressure-sensitive adhesive polymer electrolyte as claimed in one of claims 1 to 10, wherein the pressure-sensitive adhesive tape is typically double-sided and in particular is an adhesive transfer tape.

12. A roll of product comprising (a) a roll core and (b) a pressure-sensitive adhesive polymer electrolyte as claimed in one of claims 1 to 10 in the form of a web, or a pressure-sensitive adhesive tape as claimed in claim 11, wherein the pressure-sensitive polymer electrolyte or the pressure-sensitive adhesive tape is wound onto the roll core in multiple plies in the form of an Archimedean spiral.

13. Use of the pressure-sensitive adhesive polymer electrolyte as claimed in one of claims 1 to 10 or of the pressure-sensitive adhesive tape in accordance with claim 11 in electrochromic glazing or in a battery.

14. An electrochromic system comprising a first half-cell A and a second half-cell B, wherein the two half-cells A and B are connected to each other over the entire area or a portion of the area via a pressure-sensitive adhesive polymer electrolyte as claimed in one of claims 1 to 10 or a pressure-sensitive adhesive tape as claimed in claim 11, wherein preferably, the first half-cell A has a laminar electrically conductively coated polymer or glass substrate body and an anode material is applied to the entirety of or a portion of the conductively coated side, and the second half-cell B also has a laminar and electrically conductively coated polymer or glass substrate body and a cathode material is applied to the entirety of or a portion of the electrically conductively coated side.

15. A method for the production of an electrochromic system, in which a first half-cell A and a second half-cell B are connected to each other to form an electrochromic system by lamination of a pressure-sensitive adhesive polymer electrolyte as claimed in one of claims 1 to 10 or of a pressure-sensitive adhesive tape as claimed in claim 11, wherein the half-cells A and B are preferably as defined in claim 14.