Polyacrylate and pressure-sensitive adhesive based on it

Abstract

Polyacrylate, characterized in that - the polyacrylate is based on the following monomer composition: a) 65 to 80 wt.% of at least one acrylic acid ester according to formula (I) CH2=CH-C(O)OR 1 (I), where R 1 represents a linear alkyl group having 1 to 4 C atoms; b) 10 to 20 wt.% of at least one acrylic acid ester according to formula (II) CH2=CH-C(O)OR 2 (II), where R 2 represents a phenoxyalkyl radical; c) 10 to 15 wt.% of at least one acrylic monomer according to formula (III) CH2=CH-C(O)OR 3 (III), where R 3 represents a hydrogen atom or a hydroxyalkyl radical with 1 to 4 carbon atoms: - the polyacrylate has a weight-average molecular weight of 600,000 to 1,200,000 g / mol; and - the polyacrylate was produced by free radical polymerization, ATRP, nitroxide / TEMPO-controlled polymerization or RAFT process.

Description

[0001] The invention relates to the technical field of polyacrylates, which are widely used, among other things, as base components in adhesives, especially in pressure-sensitive adhesives. More specifically, the invention relates to a polyacrylate with a specific monomer composition and a heat-shear-resistant pressure-sensitive adhesive with a comparatively low bond strength, which contains such a polyacrylate and can be advantageously used for producing bonds in vehicle batteries.

[0002] Global climate change is now omnipresent and clearly noticeable in many parts of the world. Preventing profound climate change is now widely accepted as a task for society as a whole. This requires far-reaching changes in many areas of technology. A significant proportion of climate-damaging emissions are attributable to mobility. Therefore, great efforts are being made to continue enabling diverse individual mobility while reducing the resulting emissions of climate-damaging emissions to a tolerable level. In this context, electromobility and the use of batteries as energy suppliers for vehicle operation play a key role.

[0003] Accumulators – or batteries – for vehicles typically contain a series of interconnected modules (so-called stacks). These modules, in turn, consist of several individual battery cells. There are three types of cells: Prismatic cells are based on deep-drawn aluminum; they are comparatively heavy. Since the weight of the battery represents a significant disadvantage for the efficiency of electric vehicles, there are reservations about the use of prismatic cells.

[0004] A second group consists of cylindrical cells. Due to their cylindrical shape, these cells are difficult to pack efficiently, so batteries based on this type of cell require quite a lot of space.

[0005] The third group are so-called pouch cells. These are polymer-aluminum laminates into which the actual battery cell is welded. Pouch cells are particularly characterized by their low weight and allow for a comparatively high energy density in the battery. They are often considered the most advantageous battery cells.

[0006] Within a battery module, the individual pouch cells are bonded together, sometimes with the aid of a foamed spacer. The cells can thus be arranged in a "cell-adhesive-cell" or "cell-adhesive-spacer-cell" configuration. Adhesive tapes are increasingly being used as adhesives, and their properties are subject to stringent requirements.

[0007] A key challenge in electric vehicle operation remains thermal management, as batteries heat up during operation. Temperatures of approximately 40 to 60 °C arise, which the adhesive tapes used to bond the pouch cells must withstand.

[0008] A further requirement arises from the battery module manufacturing process. The pouch cells are glued together in a largely automated process. If errors occur, such as creases or misalignment of the cells, the affected modules are sorted out and stored to be corrected in a coordinated step. The storage times for this can be one to two weeks. After this time, the adhesives between the pouch cells must be able to be removed without great effort so that the bonding can be corrected. If the adhesives offer too much resistance to being removed, the cell packaging may tear, which could result in electrolyte leaking from the battery cells, for example. In this respect, the ability of the adhesives to be removed again is also very important.

[0009] Pressure-sensitive adhesives based on poly(meth)acrylates with aromatic components are known in the art.

[0010] US 6,312,799 B1, for example, concerns an acrylate pressure-sensitive adhesive containing a copolymer of the following monomer mixture: - 40 to 80 wt.% of a phenoxyalkyl (meth)acrylate, the phenyl group of which may be mono- or dialkyl-substituted; - 19 to 40 wt.% of an alkyl (meth)acrylate whose alkyl group has 2 to 14 carbon atoms; and - 1 to 20 wt.% of a copolymerizable monoethylenically unsaturated monomer.

[0011] EP 2 233 546 A2 describes a pressure-sensitive adhesive composition which - a crosslinkable acrylate copolymer A containing a monomer having a crosslinking functional group; and - a non-crosslinkable copolymer B in a mixing ratio of 1:9 to 5:5, wherein each of copolymers A and B contains 75 to 97 wt% of a (meth)acrylic acid ester monomer and 3 to 25 wt% of a monomer having an aromatic group.

[0012] EP 1 275 706 A1 discloses a pressure-sensitive adhesive comprising an acrylate copolymer which comprises, as copolymerizable components, an acrylalkyl ester which does not contain an aromatic ring and a monomer which contains an aromatic ring and is present in the monomer mixture at 40 to 90 wt.%.

[0013] WO 2019 / 106194 A1 relates to a polyacrylate which is based on the following monomer composition: - 30 to 75 wt.% of an alkyl acrylate; - 20 to 65% by weight of an acrylic acid phenoxyalkyl ester; - 0 to 40 wt.% of an alkyl diglycol acrylate and / or an alkoxyalkyl acrylate; and - 0.5 to 10 wt.% acrylic acid and / or a hydroxyalkyl ester of acrylic acid.

[0014] The document also relates to a pressure-sensitive adhesive based on such a polyacrylate.

[0015] JP 2020-019869 A describes an adhesive composition containing a (meth)acrylic acid ester polymer (A) and a reactive component (B), wherein the (meth)acrylic acid ester polymer (A) is used as constituent monomers - a monomer containing an aromatic ring at 2.5 to 30 wt.% and - contains a monomer containing a reactive functional group at 5 to 30 wt.%.

[0016] There is a continuing need for polymers that can serve as a basis for pressure-sensitive adhesives, which in turn are suitable for bonding in vehicle batteries. The object of the invention was to provide such a polymer, with the pressure-sensitive adhesives based thereon exhibiting high shear strengths at elevated temperatures and good removability even after several days of storage.

[0017] A first and general subject of the invention, with which the above object is achieved, is a polyacrylate which is characterized in that - the polyacrylate is based on the following monomer composition: a) 65 to 80 wt.% of at least one acrylic acid ester according to formula (I) CH2=CH-C(O)OR 1 (I), where R 1 represents a linear alkyl group having 1 to 4 C atoms; b) 10 to 20 wt.% of at least one acrylic acid ester according to formula (II) CH2=CH-C(O)OR 2 (II), where R 2 represents a phenoxyalkyl radical; c) 10 to 15 wt.% of at least one acrylic monomer according to formula (III) CH2=CH-C(O)OR 3 (III), where R 3 represents a hydrogen atom or a hydroxyalkyl radical having 1 to 4 carbon atoms; - the polyacrylate has a weight-average molecular weight of 600,000 to 1,200,000 g / mol; and - the polyacrylate was produced by free radical polymerization, ATRP, nitroxide / TEMPO-controlled polymerization or RAFT process.

[0018] As has been shown, such polymers meet the requirements described above and are therefore very well suited as base materials for pressure-sensitive adhesives for bonding in battery cells.

[0019] R 1 in formula (I) represents a linear alkyl group having 1 to 4 C atoms. In particular, R 1represents an n-butyl or methyl radical. Most preferably, R 1 in formula (I) represents an n-butyl radical. Monomers a) are preferably present in the monomer composition of the polyacrylate according to the invention in a total amount of 68 to 78 wt. %, with n-butyl acrylate being present in particular in this proportion.

[0020] R 2 in formula (II) preferably represents a phenoxyethyl radical, in particular a 2-phenoxyethyl radical. Monomers b) are preferably present in the monomer composition of the polyacrylate according to the invention in a total amount of 12 to 18 wt. %, with 2-phenoxyethyl acrylate being present in particular in this proportion.

[0021] R 3 in the formula (III) preferably represents a hydrogen atom.

[0022] In one embodiment, the polyacrylate according to the invention is based on the following monomer composition: n-butyl acrylate at 65 to 80 wt.%, 2-phenoxyethyl acrylate at 10 to 20 wt.% and acrylic acid at 10 to 15 wt.%.

[0023] The polyacrylate according to the invention is particularly preferably based on the following monomer composition: n-butyl acrylate at 70 to 76 wt.%, 2-phenoxyethyl acrylate at 12 to 18 wt.% and acrylic acid at 10 to 14 wt.%.

[0024] The polyacrylate according to the invention is preferably crosslinked. The polyacrylate is particularly preferably thermally crosslinked. Thermal crosslinking can be carried out under significantly milder conditions than, for example, radiation-induced crosslinking, which can occasionally also be destructive. In principle, however, it is also possible to effect crosslinking of the polyacrylate exclusively or additionally by actinic radiation, in which case, if necessary or beneficial, crosslinking substances, e.g., UV crosslinkers, can be added.

[0025] The polyacrylate according to the invention is therefore preferably thermally crosslinked, i.e., by means of substances that enable (initiate) and / or promote a crosslinking reaction under the influence of thermal energy. Preferred thermal crosslinkers are covalently reacting crosslinkers, in particular epoxides, isocyanates, and / or aziridines, and coordinative crosslinkers, particularly preferably metal chelates, in particular aluminum, titanium, zirconium, and / or iron chelates. Combinations of different crosslinkers, e.g., a combination of one or more epoxides with one or more metal chelates, can also be used.

[0026] The polyacrylate according to the invention is particularly preferably crosslinked with at least one covalent crosslinker.

[0027] Particularly preferred metal chelates are aluminum chelates, for example aluminum(III) acetylacetonate. These crosslinkers are preferably used in an amount of 0.1 to 0.8 parts by weight, particularly preferably 0.2 to 0.7 parts by weight, based in each case on 100 parts by weight of the (solvent-free) polyacrylate.

[0028] Particularly preferred covalent crosslinkers are epoxides, especially those with tertiary amine functions such as tetraglycidyl meta-xylenediamine (N,N,N',N'-tetrakis(oxiranylmethyl)-1,3-benzenedimethanamine) or cycloaliphatic epoxy resins such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate. These compounds are preferably used in an amount of 0.03 to 0.1 part by weight, particularly preferably 0.04 to 0.07 part by weight, based in each case on 100 parts by weight of the polyacrylate (solvent-free).

[0029] Free radical polymerization, ATRP, nitroxide / TEMPO-controlled polymerization or the RAFT process are used to produce polyacrylates according to the invention.

[0030] The polyacrylate according to the invention has a weight-average molecular weight of 600,000 to 1,200,000 g / mol.

[0031] The invention further provides a pressure-sensitive adhesive comprising at least one polyacrylate according to the invention in a total amount of at least 50% by weight. A pressure-sensitive adhesive according to the invention is characterized by high shear strength, even at elevated temperatures, and by comparatively easy removability.

[0032] 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, whereby the pressure to be applied and the duration of this pressure are not defined in more detail. In general, however, depending 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 adhesion effect; in other cases, a longer exposure period of higher pressure may be necessary.

[0033] 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.

[0034] 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 adhesion (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 pressure-sensitive due to the lack of flowable components.

[0035] 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 sufficiently withstand continuous loading, for example, in the form of permanent shear stress, over an extended period of time.

[0036] The polyacrylate of the invention is preferably pressure-sensitively adhesive. In the simplest case, the pressure-sensitive adhesive of the invention therefore consists of one or more polyacrylates of the invention, in particular a thermally crosslinked polyacrylate. Production-related impurities such as solvent residues or unreacted monomers are irrelevant.

[0037] The pressure-sensitive adhesive according to the invention may contain additives such as adhesive resin and / or plasticizer.

[0038] Adhesive resins, also known as tackifying resins, are often added to pressure-sensitive adhesives to fine-tune their adhesive properties.

[0039] According to the invention, “resins” are understood to mean in particular those oligo- and (low) polymeric compounds whose number-average molecular weight M n not exceeding 5,000 g / mol. Naturally, short-chain polymerization products formed during the polymerization of the polyacrylate of the invention are not subsumed under the term "resins." Adhesive resins generally increase the bond strength, particularly the "tack," or "touch tack," of a pressure-sensitive adhesive.

[0040] Adhesive resins often have softening points in the range of 80 to 150 °C. The information on the softening point T Eof oligomeric and polymeric compounds, such as resins, refer to the ring-and-ball method according to DIN EN 1427:2007 with appropriate application of the specifications (examination of the oligomer or polymer sample instead of bitumen, with otherwise unchanged procedure). The measurements are carried out in a glycerol bath.

[0041] If present at all, the pressure-sensitive adhesive of the invention comprises at least one tackifier resin selected from the group consisting of pinene and indene resins; rosin and rosin derivatives such as rosin esters, including rosin derivatives stabilized by, for example, disproportionation or hydrogenation; polyterpene resins; terpene-phenolic resins; alkylphenol resins; and aliphatic, aromatic, and aliphatic-aromatic hydrocarbon resins. The tackifier resins are optionally present in the pressure-sensitive adhesive of the invention, preferably in a total amount of not more than 30% by weight. One or more tackifier resins may be present.

[0042] In addition, a pressure-sensitive adhesive according to the invention may also contain reactive resins. Reactive resins are understood to be resins that have functional groups such that they can chemically react with other components of the pressure-sensitive adhesive, in particular the polyacrylate(s), upon suitable activation.

[0043] The pressure-sensitive adhesive according to the invention is preferably free of adhesive resins.

[0044] Plasticizers, if present at all, are preferably selected from the group consisting of (meth)acrylate oligomers, phthalates, hydrocarbon oils, cyclohexanedicarboxylic acid esters, benzoic acid esters, water-soluble plasticizers, plastic resins, phosphates, and polyphosphates. Plasticizers are optionally present in the pressure-sensitive adhesive of the invention in a total amount of not more than 30 wt.%, particularly preferably not more than 20 wt.%, and in particular not more than 15 wt.%.

[0045] The pressure-sensitive adhesive according to the invention is preferably free of plasticizers.

[0046] With regard to both the characteristic “free from adhesive resins” and the characteristic “free from plasticizers,” proportions in the range of the ubiquitous concentration as well as production-related residues – for example, resulting from the production of the polyacrylate or crosslinker used – are irrelevant.

[0047] To optimize the properties of the pressure-sensitive adhesive according to the invention, it may also contain other common additives such as fillers, for example electrically conductive fillers, thermally conductive fillers and the like, or flame retardants, for example ammonium polyphosphate and / or its derivatives.

[0048] The pressure-sensitive adhesive of the invention can also be foamed. A "foamed pressure-sensitive adhesive" is understood to mean a pressure-sensitive adhesive comprising a pressure-sensitively adhesive matrix material and a plurality of gas-filled cavities, such that the density of this pressure-sensitive adhesive is reduced compared to the mere matrix material without cavities. The foaming of the matrix material of the foamed pressure-sensitive adhesive—provided the pressure-sensitive adhesive is foamed at all—can in principle be achieved in any desired manner. For example, the pressure-sensitive adhesive can be foamed by means of a propellant gas introduced into or released into the pressure-sensitive adhesive, or it can contain expanded hollow microspheres.

[0049] The pressure-sensitive adhesive according to the invention is preferably not foamed.

[0050] The production of a pressure-sensitive adhesive according to the invention preferably proceeds by first preparing the polyacrylate(s) from the corresponding underlying monomer mixtures by free-radical polymerization. If multiple polyacrylates are present, these are then thoroughly mixed. If required, crosslinkers are added during or, preferably, after polymerization. If further additives are to be added, these are also mixed in.

[0051] A pressure-sensitive adhesive according to the invention is preferably coated as a solution—optionally after adjusting a specific solids content—onto a carrier or a release liner. Coating is preferably carried out using conventional coating processes such as anilox roll coating, comma coating, multi-roll coating, or a printing process. The solvent can subsequently be removed in a drying tunnel or oven.

[0052] When using thermal crosslinkers, crosslinking generally occurs to a lesser extent at room temperature and to a greater extent upon application of heat, especially during solvent removal. Coordinative crosslinkers generally crosslink the polyacrylate regardless of temperature; for this reason, substances are occasionally added that initially block the crosslinker. These are then removed with the solvent, so that crosslinking begins immediately at this point.

[0053] Alternatively, the coating can also be applied using a solvent-free process. For this, the polyacrylate is heated and melted in an extruder. Further process steps such as mixing with additives, filtration, or degassing can be performed in the extruder. The melt is then applied as a layer to a carrier or release liner using a calender.

[0054] Another subject of the invention is an adhesive tape comprising a pressure-sensitive adhesive according to the invention.

[0055] In the simplest case, an adhesive tape according to the invention consists only of a pressure-sensitive adhesive according to the invention. To enable application of the adhesive tape, rolled into a plate reel or cross-wound into a spool, without it sticking to itself, the pressure-sensitive adhesive is preferably covered with at least one release liner.

[0056] An adhesive tape according to the invention can, in addition to a pressure-sensitive adhesive according to the invention, also comprise at least one carrier and optionally also further layers, for example further pressure-sensitive adhesive layers, barrier layers, further reinforcing carrier layers, etc. In principle, there are no restrictions with regard to the design of the carrier and the further layers. Typical carrier materials are, for example, woven fabrics, scrims and plastic films, for example PET films and polyolefin films. Foamed carrier materials are also suitable. In such embodiments, too, at least one pressure-sensitive adhesive of the adhesive tape is preferably covered with a release liner in order to enable problem-free unwinding and to protect the pressure-sensitive adhesive(s) from contamination. Release liners usually consist of a plastic film (e.g. PET or PP) siliconized on one or both sides or a siliconized paper carrier.They are not considered part of the adhesive tape, but are only temporarily connected to it as an aid.

[0057] The invention further provides for the use of a polyacrylate of the invention or a pressure-sensitive adhesive of the invention for producing bonds in rechargeable batteries, preferably in vehicle batteries. The pressure-sensitive adhesive of the invention or an adhesive tape containing this pressure-sensitive adhesive is particularly preferably used for bonding pouch cells in vehicle batteries. Examples: Production of polyacrylates

[0058] A 300 L reactor conventional for radical polymerizations was charged with a total of 100 kg of the monomers listed in Table 1, corresponding to the composition also specified there, as well as 72.4 kg of gasoline / acetone (70:30). After 45 minutes of nitrogen gas being passed through the reactor with stirring, the reactor was heated to 58 °C and 50 g of Vazo® 67 were added. The jacket temperature was then heated to 75 °C and the reaction was carried out at this constant external temperature. After a reaction time of 1 h, another 50 g of Vazo® 67 were added. After 3 h, the mixture was diluted with 20 kg of gasoline / acetone (70:30) and after 6 h with 10.0 kg of gasoline / acetone (70:30). To reduce the residual initiators, 0.15 kg of Perkadox® 16 was added after 5.5 and after 7 h. The reaction was stopped after 24 hours and cooled to room temperature. The solution was adjusted to a solids content of 38 wt.%. Finally, 0.075 wt.% of the crosslinker was added.-%, based on the polymer, Erysis GA240 (epoxy crosslinker) was stirred in.

[0059] The resulting composition was coated in solution onto a siliconized PET film using a comma coating machine. The solvent was removed in a drying tunnel (20 min, 80 °C), and the final coating weight was 50 g / cm 2 In the tests described below, the adhesives obtained in this way were used as transfer adhesive tape. Static shear test

[0060] The shear strength was determined at a test temperature of 80 °C + / - 1 °C and 50% + / - 5% relative humidity.

[0061] The test samples were cut to a width of 25 mm and stored at room temperature for 24 hours. 25 x 100 mm PET-coated aluminum pouch films were used for the test. The bonding area was 25 x 25 mm. The test strip was applied longitudinally to the center of the substrate by brushing over it with a wiper, avoiding air pockets.

[0062] Since the tested samples were double-sided, the back was also sealed with a PET-coated aluminum pouch film. The adhesive strip was rolled back and forth twice using a 2 kg roll. After rolling, two strap loops (weighing 5-7 g) were attached to the protruding end of the test sample.

[0063] The prepared samples were attached to a counter using a hook; a 1 kg weight was then smoothly hung in the strap loop.

[0064] The application time between rolling and loading was 24 hours. The time until bond failure was then measured in minutes; the results are the average of three measurements. T-Peel test

[0065] Two PET-coated aluminum foils were cut to 25.4 mm x 250 mm. The pressure-sensitive adhesive was then cut to 25.4 mm x 127 mm. The two aluminum foils were then bonded together using the pressure-sensitive adhesive and rolled back and forth twice using a 2 kg roller. The produced test specimen was then stored for 24 or 48 hours at 23 °C and 50% relative humidity. The test specimen was then clamped in a ZWICK tensile testing machine, whereupon the protruding aluminum foils were pulled apart at a speed of 254 mm / min. The maximum force required for this was measured; the result is given in Table 2 as the average of two individual measurements in N / cm. Table 1: Composition of polyacrylates Nr. Acrylic acid (wt%) 2-Phenoxyethyl acrylate (wt%) n-Butyl acrylate (wt%) Methyl acrylate (wt.%) 1 (V) 12 0 88 0 2 (V) 3 30 47 20 3 (V) 7 0 73 20 4 (V) 8 14 78 0 5 (V) 15 8 77 0 6 (V) 8 8 76 0 7 10 10 80 0 8 12 15 63 0 9 15 18 67 0 10 15 10 75 0 V = comparison example Table 2: Test results Nr. Static shear test T-Peel 24 h T-Peel 48 h T-Peel residues 1 (V) 0,5 h 2 2,3 Yes 2 (V) > 24 h 3,7 4,1 Yes 3 (V) > 0,5 h 4,3 4,6 Yes 4 (V) > 24 h 3,8 4,4 Yes 5 (V) 15 h 2 2,4 no 6 (V) 3 h 3,1 3,6 Yes 7 > 24 h 2,4 2,6 no 8 > 24 h 1,8 1,7 no 9 > 24 h 1,9 1,8 no 10 > 24 h 2,2 2,1 no

Claims

[1] Polyacrylate, characterized by , that - the polyacrylate is due to the following monomer composition: a) 65 to 80 wt.% of at least one acrylic acid ester according to formula (I) CH2=CH-C(O)OR 1 (I), in which R 1 stands for a linear alkyl group with 1 to 4 carbon atoms; b) 10 to 20 wt.% of at least one acrylic acid ester according to formula (II) CH2=CH-C(O)OR 2 (II), in which R 2 stands for a phenoxyalkyl residue; c) 10 to 15 wt.% of at least one acrylic monomer according to formula (III) CH2=CH-C(O)OR 3 (III), in which R 3 for a hydrogen atom or a hydroxyalkyl group with 1 to 4 carbon atoms: - the polyacrylate has a weight-average molecular weight of 600,000 to 1,200,000 g / mol; and - the polyacrylate was produced by free radical polymerization, ATRP, nitroxide / TEMPO-controlled polymerization or RAFT process. [2] Polyacrylate according to claim 1, characterized by , that R 1 stands for a methyl or n-butyl residue. [3] Polyacrylate according to any one of the preceding claims, characterized by , that R 2 stands for a phenoxyethyl residue. [4] Polyacrylate according to any one of the preceding claims, characterized by , that R 3 stands for a hydrogen atom. [5] Adhesive compound containing at least 50% by weight of at least one polyacrylate according to any one of claims 1 to 4. [6] Adhesive tape comprising an adhesive compound according to claim 5. [7] Use of an adhesive compound according to claim 5 for the production of bonds in accumulators. [8] Use according to claim 7 for bonding pouch cells in vehicle batteries.