Thermoplastic elastomer composition having flame-retardant properties and adhesion to adhesive tapes

Abstract

The invention relates to a thermoplastic elastomer composition comprising a styrene block copolymer, a non-elastomeric thermoplastic, a non-polar polymeric plasticizer and a flame retardant, wherein the weight ratio of styrene block copolymer to the non-polar polymeric plasticizer is in the range of 0.7 to 3.

Description

[0001] Thermoplastic elastomer composition with flame-retardant properties and adhesion to adhesive tapes

[0002] The present invention relates to a thermoplastic elastomer composition comprising a styrene block copolymer, a non-elastomeric thermoplastic, a non-polar polymeric plasticizer, and a flame retardant, wherein the weight ratio of styrene block copolymer to the non-polar polymeric plasticizer is in the range of 0.7 to 3. The thermoplastic elastomer composition according to the invention exhibits good flame-retardant properties and good adhesion to adhesive tapes.

[0003] To store energy for electric vehicles, batteries are typically used, containing many electrochemical cells stacked side by side. These stacked electrochemical cells usually each have an aluminum cell casing. A plastic sealing material is typically used between the cell casings to compensate for tolerances. Double-sided adhesive tape is used to bond the cells together in a secure stack, bonding the cell casings to the sealing material. The sealing material must meet several requirements: due to the heat generated by the electrochemical cells during operation, it must have excellent flame-retardant properties (preferably V0 flame-retardant) to prevent battery fires. The sealing material must also adhere well to the adhesive tape to ensure a sufficiently strong bond between the stacks.

[0004] The object of the present invention is to provide a sealing material that satisfies all these requirements together and to a sufficient degree.

[0005] According to the invention, a thermoplastic elastomer composition is provided for this purpose, comprising a styrene block copolymer, a non-elastomeric thermoplastic, a non-polar polymeric plasticizer, and a flame retardant. The weight ratio of styrene block copolymer to the non-polar polymeric plasticizer is in the range of 0.7 to 3, preferably in the range of 0.8 to 2.5, more preferably in the range of 0.9 to 2, and even more preferably in the range of 1 to 1.6. A ratio that is too low results in reduced adhesion to the adhesive tape. The same applies to a ratio that is too high.

[0006] In one embodiment of the thermoplastic elastomer composition according to the invention, it is preferred that the styrene block copolymer is a tri-block copolymer. The styrene content of the styrene block copolymer is preferably less than 38 wt.%, based on the total weight of the styrene block copolymer, so that the Shore hardness of the resulting thermoplastic composition is not too high and can be adjusted within the desired range. Furthermore, this ensures the elastomeric properties of the composition according to the invention.

[0007] In a further embodiment of the thermoplastic elastomer composition according to the invention, it is preferred that the non-elastomeric thermoplastic is a polyolefin. The polyolefin is preferably one with a weight-average molecular weight Mw in the range of 200,000 Da to 500,000 Da, more preferably in the range of 235,000 Da to 435,000 Da, and even more preferably in the range of 270,000 Da to 400,000 Da. In this way, the Shore hardness of the resulting thermoplastic composition can be adjusted within the desired range. It is further preferred that the polyolefin is a polypropylene or polyethylene, with polypropylene being particularly preferred.

[0008] In a further embodiment of the thermoplastic elastomer composition according to the invention, it is preferred that the non-polar polymeric plasticizer is a polyolefin. If the non-polar polymeric plasticizer and the non-elastomeric thermoplastic are both polyolefins, then these are different polyolefins. The non-polar polymeric plasticizer preferably has a weight-average molecular weight Mw in the range of 1,000 Da to 5,000 Da, more preferably in the range of 1,500 Da to 3,500 Da, and most preferably in the range of 2,000 Da to 3,000 Da. Preferably, the non-polar polymeric plasticizer differs from a plasticizer based on paraffin oil, or has a higher viscosity than paraffin oils. This increases the adhesion to adhesive tapes. The non-polar polymeric plasticizer is particularly preferably a polyolefin with three or more carbon atoms per repeating unit.The non-polar polymeric plasticizer polybutylene or polyisobutylene is particularly preferred.

[0009] The flame retardant used in the thermoplastic elastomer composition according to the invention is preferably a phosphorus-containing flame retardant, more preferably one in which the phosphorus has bonds to oxygen. Flame retardants based on a phosphate or a phosphinate are preferred. If a phosphate is used, it is preferably in the form of a polyphosphate, particularly preferably as ammonium or alkali polyphosphate.

[0010] In a further embodiment of the thermoplastic elastomer composition according to the invention, it is preferred that it comprises two different flame retardants. It is preferred that one of the flame retardants is phosphate-based and the other flame retardant is phosphinate-based.

[0011] In a further embodiment of the thermoplastic elastomer composition according to the invention, it is preferred that it comprises a dispersing agent for the flame retardant(s). The dispersing agent ensures that the flame retardant(s) are distributed uniformly throughout the composition and thus exert a flame-retardant effect in every region of the composition.

[0012] In a further embodiment of the composition according to the invention, it is preferred that it consists of the following components: styrene block copolymer, non-elastomeric thermoplastic, non-polar polymeric plasticizer, and a flame retardant, as well as optionally a dispersant, optionally a dye, optionally further additives such as light stabilizers, antioxidants, and metal deactivators, and optionally another non-polymeric plasticizer, wherein the weight ratio of styrene block copolymer to the non-polar polymeric plasticizer is in the range of 0.7 to 3. In a further embodiment of the present invention, the thermoplastic composition according to the invention is used for adhesion on an adhesive tape.In other words, the present invention also includes a method for producing a composite of the thermoplastic elastomer composition and an adhesive tape, wherein the thermoplastic elastomer composition is applied to an adhesive tape. In the use or method according to the invention, the adhesive tape is preferably used to join accumulator cells into a stack.

[0013] The adhesive tape is preferably a double-sided tape that is bonded on one side to the thermoplastic elastomer according to the invention and on the other side to the housing of a battery cell. The adhesive of the double-sided tape is preferably acrylic-based. The carrier of the adhesive is made of a plastic material, preferably PET. Adhesive tapes from Tesa are preferably used here, for example Tesa 4965 or Tesa T58364.

[0014] A: Styrene block copolymer

[0015] B: non-elastomeric thermoplastic

[0016] C: non-polar polymeric plasticizer

[0017] D: Flame retardant

[0018] E: Dispersing agent

[0019] Q: Dye

[0020] G: Additive

[0021] H: non-polymeric plasticizer

[0022] Component A: Styrene block copolymer

[0023] According to the invention, the term "styrene block copolymer" (SBC) refers to a multi-block copolymer, wherein at least one of the blocks is polystyrene. At least one of the other blocks comprises polybutadiene, polyisoprene, or polyisobutene. The SBC can be a tri-block copolymer of the structure AB-A, wherein the A-block is typically polystyrene and the B-block is typically composed of polybutadiene, polyisoprene, or polyisobutene (SBS, SIS, SiBS). Alternatively, in the A-block, the styrene monomers can be partially or completely replaced by derivatives of styrene, such as α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-tert-butylstyrene, 4-cyclohexylstyrene, or vinylnaphthalene such as 1-vinylnaphthalene and 2-vinylnaphthalene. The B-block can also alternatively contain mixtures of dienes such as SIBS (B-block made from a mixture of butadiene and isoprene).Furthermore, SBCs consisting of styrene and diene monomers can also be used as hydrogenated derivatives. In these cases, the B-block units are partially or completely hydrogenated. Polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS), polystyrene-block-poly(ethylene-co-propylene)-block-polystyrene (SEPS), and polystyrene-block-poly(ethylene-co-(ethylene-propylene))-block-polystyrene (SEEPS) are preferred examples. In addition to triblock copolymers, diblock, tetrablock, or multiblock copolymers made from the aforementioned monomers of styrene, styrene derivatives (A-blocks), and butadiene, isoprene, isobutylene, and their mixtures (B-blocks) in various sequences of A- and B-blocks (e.g., BAB, ABAB, etc.) can also be used. Preferred SBCs are composed of triblock copolymers ABA. According to the invention, the SBC is particularly preferably a SEBS.

[0024] The SBC is preferably present in the thermoplastic elastomer composition according to the invention in an amount in the range of 15 wt.% to 40 wt.%, more preferably in a range of 18 wt.% to 38 wt.% and most preferably in a range of 20 wt.% to 35 wt.%, based on the total weight of the thermoplastic elastomer composition.

[0025] Component B: Non-elastomeric thermoplastic

[0026] The non-elastomeric thermoplastic is preferably a non-elastomeric polyolefin, preferably with a weight-average molecular weight Mw in the range of 200,000 Da to 500,000 Da, more preferably in the range of 235,000 Da to 435,000 Da, and even more preferably in the range of 270,000 Da to 400,000 Da. It is further preferred that the polyolefin is a polypropylene or polyethylene, with polypropylene being particularly preferred.

[0027] Non-elastomeric polyolefins include, for example, copolymers of polyethylene, such as HDPE (high density polyethylene), MDPE (medium density polyethylene), LDPE (low density polyethylene), LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene); a homopolymer of propylene; a statistical polypropylene copolymer; a statistical copolymer of propylene and ethylene; and combinations thereof.

[0028] Suitable polyolefins for the invention are primarily those that are suitable for injection molding. Suitable polyolefins are those with good flow properties and stiffness.

[0029] Homopolymers of propylene (hPP) are commercially available and any of these available hPPs can be used according to the invention.

[0030] The hPP can have a melt flow index value according to ISO 1133 (at 230°C with 2.16 kg) in the range of 0.5 g / 10 min to 200 g / 10 min, and preferably in the range of 4 g / 10 min to 50 g / 10 min; a tensile strength according to ISO 527-1, -2 in the range of 15 MPa to 50 MPa, and preferably in the range of 20 MPa to 40 MPa; an elongation at break according to ISO 527-1, -2 in the range of 1% to 500%, and preferably in the range of 10% to 300%.

[0031] Commercially available HPPs include, for example, Lyondell-Basell products sold under the trade name Moplen®, such as Moplen® HP500N and Moplen® HP501 L.

[0032] Statistical polypropylene copolymers (rPP) are also commercially available, and any of these rPPs can be used according to the invention. Ethylene and / or butene are preferred as comonomers.

[0033] The rPP can have a melt flow index according to ISO 1133 (at 230°C with 2.16 kg) in the range of 0.5 g / 10 min to 100 g / 10 min, and preferably in the range of 1 g / 10 min to 50 g / 10 min, even more preferably in the range of 5 g / 10 min to 20 g / 10 min; an elongation at break according to ISO 527-1 , -2 in the range of 1 % to 500%, and preferably in the range of 10% to 300%.

[0034] A commercially available rPP is, for example, Moplen® RP340N. Polyethylenes of different densities can be used according to the invention. These are readily available commercially.

[0035] Any polyethylene with a melt flow rate in the range of 0.5 g / min to 10 g / 10 min can be used. HDPE can have a melt flow rate according to ISO 1133 (at 190°C with 2.16 kg) in the range of 0.02 g / 10 min to 55 g / 10 min, and preferably in the range of 0.9 g / 10 min to 10 g / 10 min; a tensile strength according to ISO 527-1, -2 in the range of 12 MPa to 32 MPa, and preferably in the range of 20 MPa to 30 MPa; an elongation at break according to ISO 527-1, -2 in the range of 50% to 1200%, and preferably in the range of 600% to 700%.

[0036] LDPE can have a melt flow rate according to ISO 1133 (at 190°C with 2.16 kg) in the range of 0.5 g / 10 min to 200 g / 10 min, and preferably in the range of 0.7 g / 10 min to 7 g / 10 min; a tensile strength according to ISO 527-1, -2 in the range of 6 MPa to 33 MPa, and preferably in the range of 12 MPa to 24 MPa; an elongation at break according to ISO in the range of 100% to 800%, and preferably in the range of 500% to 750%.

[0037] However, it is particularly preferred according to the invention that the non-elastomeric polyolefin is one comprising propylene in its repeating units. Even more preferred is that the non-elastomeric polyolefin be rPP.

[0038] According to the invention, two or more different non-elastomeric thermoplastics can also be used.

[0039] Part of the non-elastomeric thermoplastic in the thermoplastic elastomer composition according to the invention can also result from the use of the non-polar polymeric plasticizer, in particular when the non-polar polymeric plasticizer is supported on a carrier material, wherein the carrier material is a non-elastomeric thermoplastic.

[0040] The total amount of the non-elastomeric thermoplastic is preferably present in the thermoplastic elastomer composition according to the invention in an amount in the range of 5 wt.% to 25 wt.%, more preferably in a range of 8 wt.% to 22 wt.% and most preferably in a range of 10 wt.% to 20 wt.%, based on the total weight of the thermoplastic elastomer composition.

[0041] The weight ratio of styrene block copolymer to the non-elastomeric thermoplastic is preferably in the range of 100:80 to 100:20, more preferably in the range of 100:70 to 100:30 and even more preferably in the range of 100:60 to 100:40.

[0042] Component C: non-polar polymeric plasticizer

[0043] The non-polar polymeric plasticizer is preferably a hydrocarbon polymer, particularly preferably a polyolefin. The non-polar polymeric plasticizer differs from the non-elastomeric thermoplastic. The difference lies particularly in the different number-average molecular weight, which is preferably lower in the non-polar polymeric plasticizer than in the non-elastomeric thermoplastic. Furthermore, the number-average molecular weight of the non-polar polymeric plasticizer is preferably higher than that of paraffin oils. The non-polar polymeric plasticizer preferably has a weight-average molecular weight Mw in the range of 1,000 Da to 5,000 Da, more preferably in the range of 1,500 Da to 3,500 Da, and most preferably in the range of 2,000 Da to 3,000 Da. Preferably, the non-polar polymeric plasticizer differs from a plasticizer based on a paraffin oil, or...preferably has a higher viscosity than paraffin oils. The non-polar polymeric plasticizer is particularly preferably a polyolefin with three or more carbon atoms per repeating unit. Polybutylene or polyisobutylene is most preferably the non-polar polymeric plasticizer.

[0044] The non-polar polymeric plasticizer can be present in a carrier material. Suitable carrier materials are primarily polyolefins that are solid at room temperature, such as polyethylene or polypropylene, or mixtures thereof. These fall under the aforementioned component B. LLDPE is particularly preferred as the carrier material. The weight ratio of non-polar polymeric plasticizer to carrier material is preferably in the range of 60:40 to 80:20, and more preferably in the range of 65:35 to 75:25.

[0045] According to the invention, for example PW 70 from Polytechs can be used.

[0046] The total amount of the non-polar polymeric plasticizer (without carrier material) in the thermoplastic elastomer composition is preferably in the range of 10 wt.% to 35 wt.%, even more preferably in the range of 15 wt.% to 30 wt.%, based on the total weight of the thermoplastic

[0047] Elastomer composition.

[0048] Component D: Flame retardant

[0049] The flame retardant is preferably a phosphorus-containing flame retardant, more preferably one in which the phosphorus is bonded to oxygen. Phosphate- or phosphinate-based flame retardants are preferred. It is further preferred that the flame retardant be non-halogenated. The flame retardant preferably has a phosphorus content in the range of 15 wt.% to 30 wt.%, more preferably in the range of 18 wt.% to 25 wt.%. It is also preferred that the decomposition temperature of the flame retardant is above 260°C, more preferably above 270°C. If a phosphinate-based flame retardant is used, it is even preferred that the decomposition temperature is above 300°C, more preferably above 310°C. The bulk density of the flame retardant is preferably in the range of 400 to 600 g / L.When preparing a 1% solution of the flame retardant in water (20°C), the pH value is preferably in the range of 4.5 to 7.5.

[0050] If a phosphate is used, it is preferably in the form of a polyphosphate, particularly preferably as ammonium or alkali polyphosphate, and most preferably as ammonium polyphosphate.

[0051] The total amount of flame retardant in the thermoplastic elastomer composition according to the invention is preferably in the range of 15 wt.% to 55 wt.%, more preferably in the range of 20 wt.% to 50 wt.%, based on the total weight of the thermoplastic elastomer composition.

[0052] If both a phosphate-based flame retardant and a phosphinate-based flame retardant are present together in the thermoplastic composition according to the invention, it is preferred that the amount of phosphate-based flame retardant is in the range of 15 wt.% to 40 wt.%, more preferably in the range of 18 wt.% to 38 wt.%, and the amount of phosphinate-based flame retardant is in the range of 2 wt.% to 7 wt.%, more preferably in the range of 2.5 wt.% to 5.5 wt.%, based on the total weight of the thermoplastic elastomer composition.

[0053] The weight ratio of flame retardant based on a phosphate to the flame retardant based on a phosphinate is preferably in the range of 4 to 10, more preferably in the range of 5 to 8.

[0054] Component E: Dispersant

[0055] The dispersing agent is preferably designed such that the flame retardant(s) are evenly distributed throughout the composition. This ensures that a flame-retardant effect can be exerted in every part of the composition.

[0056] The dispersing agent preferably consists of fatty acid derivatives, such as zinc soaps, in which the zinc content is preferably in the range of 5 wt.% to 10 wt.%, based on the total weight of the thermoplastic elastomer composition according to the invention.

[0057] The amount of dispersing agent in the thermoplastic elastomer composition according to the invention is preferably in the range of 0.5 wt.% to 3 wt.%, more preferably in the range of 0.8 wt.% to 2 wt.%, based on the total weight of the thermoplastic elastomer composition.

[0058] Component F: Dye

[0059] The thermoplastic elastomer composition may contain a dye. The dye may be any dye that is desirable for the resulting color of the thermoplastic elastomer composition according to the invention. However, "carbon black," available, for example, as PLASBLAK PE4881 from CABOT, is particularly preferred as the dye. If a dye is used, it may be in an amount of up to 5% by weight.

[0060] Component G: further additives

[0061] In addition to the components mentioned above, the thermoplastic elastomer composition according to the invention can contain further additives. These include light stabilizers, antioxidants, and metal deactivators.

[0062] Examples of light stabilizers that can be used include Tinuvin 326 from BASF, Tinuvin 622 SF from BASF or Chimasorb 944 FDL from BASF; antioxidants such as Irgafos 168 from BASF, Irganox 1330MED from BASF or Sumilizer GM from Sumimoto Chemical; and metal deactivators such as Irgametz BTZ from BASF or Irganox MD 1024.

[0063] The total amount of additives in the thermoplastic elastomer composition according to the invention is preferably in the range of 0.1 wt.% to 2 wt.%, more preferably in the range of 0.5 wt.% to 1.5 wt.%, based on the total weight of the thermoplastic elastomer composition.

[0064] Component H: non-polymeric plasticizer

[0065] In addition to the non-polar polymeric plasticizer, the thermoplastic composition according to the invention can also include a further non-polymeric plasticizer. These plasticizers can be oils, such as mineral oils and paraffin oils. An example of this is Shell Catenex Oil T 145 S.

[0066] Production of the compositions according to the invention:

[0067] The thermoplastic elastomer compositions according to the present invention can be produced by mixing components A, B, C, and D, and optionally components E, F, G, and H. The mixing can be carried out using mixing systems known in rubber and plastics technology, such as kneaders, internal mixers (e.g., internal mixers with intermeshing or tangential rotor geometries), and also in continuously mixing systems such as mixing extruders (e.g., mixing extruders with two to four or more screw drives, e.g., twin-screw extruders). Thus, in one embodiment, the present invention also relates to a process for producing the thermoplastic elastomer composition according to the invention, wherein components A, B, C, and D, and optionally E, F, G, and H, are mixed together and heat-treated.

[0068] When carrying out the manufacturing process according to the invention, it is important to ensure that the mixing temperature is high enough to allow component B to be brought into the plastic state without being damaged in the process. This is ensured if a temperature above the highest melting or softening temperature of component B is selected.

[0069] Mixing the components - insofar as they are present in the compositions - is particularly preferred at a temperature in the range of 160 °C to 280 °C and preferably 200 °C to 240 °C.

[0070] The terms “comprise”, “contain”, and “have” used in the present application are also intended to include the term “consist of” in every instance where they are used, so that these embodiments are also disclosed in this application. The aforementioned components used in the thermoplastic elastomer compositions and in the uses and processes according to the invention are described in more detail below:

[0071] Methods of determination and definitions:

[0072] Flat specimens of the respective thermoplastic elastomer compositions from Examples 1 to 5 and Comparative Examples 1 to 3, each with a surface area of ​​25 mm x 25 mm (cutout), are prepared according to the procedure described below. The specimens are wiped with isopropanol on both sides. The isopropanol is then allowed to dry. Next, the respective double-sided adhesive tape is applied to both sides, i.e., the 25 mm x 25 mm surfaces of the specimens. Simultaneously, two strips of anodized aluminum (95 mm x 25 mm x 1.5 mm) are wiped with isopropanol. The isopropanol is then allowed to dry. The protective layers of the two adhesive tapes applied to the specimens are removed, and the aluminum strips are applied to the ends of both surfaces so that they protrude in opposite directions. The bonded assembly is then...

[0073] A 10 kg weight is applied to the assembly (aluminum strip:adhesive tape:test specimen:adhesive tape:aluminum strip) for 5 minutes. The assembly is then allowed to age for 72 hours. The two ends of the aluminum strips are subsequently clamped in a Zwick Z010 tensile testing machine equipped with a 2.5 kN load cell. The adhesion specified in Tables 3 and 4 is determined by pulling on both aluminum strips at a speed of 50 mm / min until the adhesive tape tears away from the test specimen or the aluminum. The force [N] measured at tearing is recorded.

[0074] Examples of implementation:

[0075] Table 1 lists the abbreviations used for the components employed in the examples and comparison examples:

[0076] Table 1:

[0077] Examples and comparative examples:

[0078] Production of thermoplastic elastomer compositions (according to the invention and not according to the invention):

[0079] The thermoplastic elastomers of the present invention are produced by mixing the components listed in Tables 3 and 4 in a continuous process on a twin-screw extruder (48 L / D). The extruder speed is 600 rpm, and the throughput is 700 kg / h. The temperature profile ranges from 170 to 190°C. The extrudate is granulated for subsequent injection molding or extrusion processing. The test specimens are produced by injection molding with a temperature profile of 200°C to 220°C. Table 2 lists the manufacturers and types of the components used. The adhesion values ​​on Tesa 4965 and Tesa T58364 adhesive tapes are given below in Tables 3 and 4, respectively. Table 2:

[0080] 1) a paraffin oil; 2)Flame retardant based on ammonium polyphosphate; 3) Flame retardant based on a phosphinate;

[0081] 4) Polytechs PW70 has an average content of non-elastomeric thermoplastic (support material) of 30 wt.% and an average content of non-polar polymeric plasticizer (polyisobutylene) of 70 wt.%.

[0082] Table 3:

[0083] 1) 20 wt.% of Moplen RP340N and 30 wt.% of PW70; 2) The total weight fraction is polyisobutylene from PW70

[0084] Table 4:

[0085] 1) 20 wt.% of Moplen RP340N and 30 wt.% of PW70; 2) The total weight fraction is polyisobutylene from PW70; 3) 25 wt.% of Moplen RP340N and 30 wt.% of PW70

Claims

Patent claims 1. Thermoplastic elastomer composition comprising a styrene block copolymer, a non-elastomeric thermoplastic, a non-polar polymeric plasticizer and a flame retardant, wherein the weight ratio of styrene block copolymer to the non-polar polymeric plasticizer is in the range of 0.7 to 3.

2. Thermoplastic elastomer composition according to claim 1, wherein the styrene block copolymer is a tri-block copolymer.

3. Thermoplastic elastomer composition according to claim 1 or 2, wherein the styrene content of the styrene block copolymer is less than 38 wt.%, based on the total weight of the styrene block copolymer.

4. Thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the non-elastomeric thermoplastic is a polyolefin.

5. Thermoplastic elastomer composition according to claim 4, wherein the polyolefin is polypropylene or polyethylene.

6. Thermoplastic elastomer composition according to any one of claims 1 to 5, wherein the non-polar polymeric plasticizer is a polyolefin that differs from the non-elastomeric thermoplastics.

7. Thermoplastic elastomer composition according to one of claims 1 to 6, wherein the non-polar polymeric plasticizer is a polyolefin with three or more carbon atoms per repeating unit.

8. Thermoplastic elastomer composition according to claim 7, wherein the non-polar polymeric plasticizer is polybutylene or polyisobutylene.

9. Thermoplastic elastomer composition according to any one of claims 1 to 8, wherein the flame retardant is a phosphorus-containing flame retardant.

10. Thermoplastic elastomer composition according to claim 9, wherein the flame retardant is based on a phosphate or on a phosphinate.

11. Thermoplastic elastomer composition according to one of claims 1 to 10, which contains two different flame retardants.

12. Thermoplastic elastomer composition according to one of claims 1 to 11 , which contains a dispersant for the flame retardant(s).

13. Use of the thermoplastic elastomer composition according to any one of claims 1 to 12 for adhesion to an adhesive tape.

14. Use of the thermoplastic elastomer composition according to claim 13, wherein the adhesive tape is used to join battery cells into a stack.

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