Use of a mixture for the production of carriers for adhesive tapes

Abstract

Use of a mixture for producing carriers for adhesive tapes, comprising at least one chain-shaped or branched silane-modified, alkoxysilated prepolymer, at least one foaming agent and at least one catalyst, wherein when several prepolymers are used, these are crosslinked with one another by splitting off alcohol, wherein the carrier is a foamed carrier and wherein the foaming agents are hollow glass spheres, expandable or pre-expanded microballoons, wherein the mixture is composed of at least 40 - 99% silane-modified alkoxylated prepolymers, 0 - 10% foaming agent and 0.1 - 5% catalyst, wherein the proportions are to be understood as proportions by weight and add up to 100%, wherein the mixture contains 0.1 to 3%, based on the total formulation, of at least one age inhibitor and 0.1 to 3%, based on the total formulation,at least one UV protection agent and whose water vapor permeability is greater than 200 g / (m 2 *d).,

Description

[0001] The present invention relates to the use of a mixture for producing carriers for adhesive tapes.

[0002] Adhesive tapes are now widely used in a wide range of industrial and consumer products and production processes. Adhesive tapes are available in single-sided or double-sided form, or as carrier-free transfer films. Single-sided and double-sided adhesive tapes contain a carrier that is coated or laminated with adhesive on one or both sides. This carrier can be made of paper, film, textile, or foam.

[0003] Foam carriers in double-sided adhesive tapes are designed to provide flexible tolerance compensation for the bonding substrates. Their conformability also provides better bonding properties than solid carriers, such as films. The bond remains flexible throughout its lifetime because the foam carrier can compensate for varying substrate expansion better than rigid carrier materials such as films. This improves the strength of the bond. The thickness of foam carriers is typically between 0.07 and 3.0 mm. The hardness and strength of the foams can be adapted to the bonding task. An overview of possible foam materials can be found, for example, in: Sekhar Sundaram, Matthieu Sonnati, Flexible Acrylic Foams: Carrier for Specialty Tapes and Beyond (2009).

[0004] Commercial foam adhesive tapes primarily use cross-linked polyolefin foam carriers (especially cross-linked polyethylene foams) and viscoelastic acrylic foams.

[0005] One advantage of acrylic foams is their viscoelasticity, which offers benefits in balancing the loads acting on the bond. Another advantage is their temperature resistance, which, due to the underlying acrylate chemistry, lies between 150°C and 200°C. The disadvantages are their relatively high specific gravity and, above all, the significant changes in properties at low temperatures. For example, acrylic foams often become hard and brittle below 0°C, particularly at temperatures below -20°C, and break under stress (e.g., impact stress). This severely limits their performance in low-temperature applications, such as outdoors, in the mobile sector, or in communications electronics. Acrylic foams are inherently adhesive, but additional adhesive layers are usually applied to high-performance adhesive tapes today.

[0006] One advantage of cross-linked polyolefin foam carriers is their stable property profile from very low temperatures down to approximately 80-100°C for polyethylene foams, their low specific weight and the associated softness, as well as their comparatively low production costs. Specific densities can range from 20 to 500 kg / m³. 3 , opening up a wide range of applications. A major disadvantage is their limited temperature resistance when used above 100°C. Furthermore, unlike acrylic foams, they are not self-adhesive, but can or must be combined with adhesive layers. The highly elastic nature of polyolefin foam carriers presents disadvantages when compensating for heavy bonding loads. Due to the non-polar nature of cross-linked polyethylene foams, they are not very permeable to water vapor, which can be a disadvantage in some applications (construction, medical).

[0007] There is therefore a need for carriers, particularly foamed carriers for adhesive tapes, which exhibit stable properties, particularly elastic behavior, over a wide temperature range and have high water vapor permeability.

[0008] The invention relates to a use of a mixture for producing carriers for adhesive tapes based on silane-modified polymers which have stable properties over wide temperature ranges and exhibit elastic behavior and high water vapor permeability.

[0009] The technology of silane-modified polymers (SMP) is state of the art.

[0010] Silane-modified polymers, also known as organofunctional silanes, are hybrid compounds that combine the functionality of a reactive organic group with the inorganic functionality of an alkyl silicate in a single molecule. They have so far been used primarily in the field of adhesives and sealants. Under the influence of moisture, they form an elastic network. Silane-modified polymers meet all the technical and ecological requirements of modern adhesives and sealants, particularly during processing. These hybrid binders enable the formulation of adhesives and sealants that are harmless to health and can be solvent-, isocyanate-, and even tin-free. The low viscosity of the prepolymers enables easy processing and opens up broad scope for the formulation of adhesives and sealants with excellent mechanical properties.Due to the high crosslinking speed, the final products also cure quickly and completely.

[0011] In principle, silanol groups in silane-modified prepolymers can be hydrolyzed under the influence of moisture and / or heat, and then form a network through alcohol cleavage and metal catalysis – the classic sealant. In the 1980s, the technology for the production and processing of so-called MS polymers was described, particularly by the company Kaneka (e.g., EP 0 295 330 A2 and EP 0 106 330 B1).

[0012] Today's sealants cure at the point of application and generally do not form a foam. A sheet-like configuration for subsequent use as a carrier sheet is also not feasible.

[0013] Patent applications have been published that use SMP as an additive to pressure-sensitive adhesives in amounts of 2–15%. By forming a network, they are said to increase the thermal stability of the pressure-sensitive adhesive layer (EP 2139967 B1, WO2010033382 A2, WO2011082094 A2).

[0014] Further publications use SMP as a polymeric base material for pressure-sensitive adhesives. Formulation with tackifier resins and other additives produces tacky pressure-sensitive adhesives similar to synthetic rubber pressure-sensitive adhesives (DE102016105339A1).

[0015] From DE 10 2014 210 309 A1, DE 102011 081 264 A1, DE 10 2012 201 734 A1, DE 10 2012 223 139 and DE 10 2012 205 306 A1, crosslinkable masses based on organyloxysilane-terminated polymers, a process for their preparation and their use as adhesives and sealants, in particular for bonding substrates, are known, wherein the masses can comprise numerous types of fillers, such as, for example, elastic plastic beads.

[0016] From WO 2014 / 029837 A1, a moist-curing mixture is known which comprises at least one prepolymer with at least one hydrolyzable silane group and can be used as an adhesive, sealant and coating.

[0017] DE 693 23 901 T2 discloses aqueous dispersions of externally chain-extended polyurethane compositions having terminal hydrolyzable and / or hydrolyzed silyl radicals and containing anionic solubilizing or emulsifying radicals, in particular carboxyl radicals.

[0018] From US 2009 / 0227710 A1, a silane-terminated polyurethane mixture is known which is the reaction product of a silane-terminated polyurethane prepolymer, a silane-terminated monomeric diisocyanate, and optionally at least one multifunctional trisilane or tetrasilane.

[0019] From WO 2015 / 113919 A1, silane-modified formamide polymers and / or prepolymers for bonding and / or sealing various substrate materials are known.

[0020] There are no publications on the formulation and production of backings for adhesive tapes made from SMP. Description of the inventionSilane-modified polymers:

[0021] Silane-modified polymers consist of a polymer that is terminally and / or laterally modified with organosilanes. The polymers are usually based on polyurethanes or polyethers. The silane end groups are usually alkyloxysilyl groups, for example, methoxylated or ethoxylated silyl groups. The silanes can carry one to three alkyloxy groups. Thus, a distinction is made between monomethoxysilyl, dimethoxysilyl (DMS), and trimethoxysilyl (TMS) types, which carry one, two, or three methoxy groups on the silicon atom, respectively. Likewise, there are now monoethoxysilyl, diethoxysilyl, and triethoxysilyl types, which carry one, two, or three ethoxy groups on the silicon atom, respectively.

[0022] The reactivity of the silane-modified polymer and the nature and density of the resulting network are controlled by the type of alkoxy radical, the number of alkoxy radicals per silicon atom, and the number and position of the silane-modified sites in the polymer molecule. In addition, the network formation and properties of the SMP are controlled by the type and chain length of the polymers, their branching, and further functionalization. The type and chain length of the polymer also determine whether the substances are low-viscosity to liquid or highly viscous at room temperature. By mixing different SMPs, the properties can be further optimized, e.g., the viscosity can be adjusted before crosslinking or the type of network formed can be optimized.

[0023] Silane-modified polymers are available, for example, from Kaneka under the brand name Silyl or MS-Polymer and the product name prefixes S, SAX, and SAT. Other manufacturers include Evonik under the brand names Tegopac and Polymer ST, and Wacker under the brand name Geniosil STP.

[0024] Silane-modified polymers based on polyether, particularly preferably based on polypropylene glycol, are preferably used.

[0025] It is advantageous if the silane-modified polymers (also referred to here as prepolymers) are liquid at room temperature, i.e., have a viscosity of less than 40 Pas. This allows them to be formulated and coated at room temperature. This has the advantage of eliminating the need for complex processing at elevated temperatures (melt).

[0026] Silane-modified polyethers with dimethoxysilyl (DMS) and trimethoxysilyl (TMS) groups are preferably used. Catalysts:

[0027] Silane-modified polymers react when exposed to moisture. The alkoxy groups are hydrolyzed, releasing alcohols, and reactive Si-OH groups are formed. These condense with each other to form stable compounds, thus forming large polymers and networks. Hydrolysis of the alkoxysilane groups is normally the rate-limiting step in the crosslinking process. Condensation is the faster reaction. The overall reaction in SMPs and formulations known for sealants proceeds very slowly, taking hours and days. This is due, among other things, to the fact that the water molecules must first reach the reactive alkoxysilanes. The water molecules are usually provided by the ambient humidity. This means that the reaction initially takes place on the surface. Water from the air only slowly diffuses into the inner layers.It is known from sealants that the "skin" formation on the surface takes a few hours, but complete curing takes days. Catalysts are used to accelerate the curing process.

[0028] In the present invention, SMPs are coated and crosslinked to form web-like supports. For this, a rapid reaction of the SMPs within minutes is essential. Therefore, catalysts are used. They control the crosslinking rate. The type and amount of catalysts are highly important for the pot life of the mixture before coating, the crosslinking temperature and rate in the furnace, and the post-crosslinking rate after removal from the furnace.

[0029] Organometallic compounds, particularly those based on tin, titanium, or zirconium compounds, are used as catalysts. Examples include the titanium-containing catalysts Tyzor TPT and Tyzor TnBT from Dorf Ketal, or Tyzor NPZ from the same company, which contains tetraalkyl zirconate, or Tyzor AA75, which contains titanium acetylacetonate (also from Dorf Ketal). Tin-based catalysts are marketed by TIB Chemicals AG under the brand name TIB KAT. Titanium catalysts are less harmful to health than tin catalysts.

[0030] Titanium-based catalysts are preferred. The catalysts are used in an amount of 0.1 to 5%, based on the total formulation. Water catcher

[0031] In the present invention, all other components are added first, followed by the catalyst. The crosslinking reaction starts even at room temperature and normal air humidity. Depending on the formulation, this occurs so quickly that the viscosity increases and / or gelling occurs before coating. This makes proper coating no longer possible. For this reason, so-called water scavengers can be added. They act as retarders and can extend the so-called pot life, i.e. the time during which coating is still possible. Vinyltrimethoxysilane is known to be very effective as a retarder. The pot life can thus be extended to a sufficient 15 to 30 minutes. The amount of vinyltrimethoxysilane also determines the retardation. This not only delays gelling before coating, but also delays subsequent complete crosslinking or curing, which is undesirable.Therefore, the retarder must be dosed in such a way that handling before coating is possible, but also that further crosslinking or complete curing is not delayed too much.

[0032] One possibility to achieve a shorter pot life would be to add the catalyst as directly as possible before coating, for example, in continuous processes using static mixers directly before the coating unit.

[0033] In the present invention, retarders were added to TMS polymers; no further retarders were added to DMS polymers. The added amount is preferably 0.1 to 3% by mass, based on the total amount of the mixture.

[0034] Vinyltrimethoxysilane is available, for example, from Wacker under the name Geniosil XL 10 or from Evonik under the name Dynasylan VTMO. foaming agent

[0035] A foamed carrier according to the invention is obtained by mixing in and subsequently expanding microballoons. "Microballoons" are understood to be elastic and thus expandable hollow microspheres that have a thermoplastic polymer shell. These spheres are filled with low-boiling liquids or liquefied gas. Polyacrylonitrile, PVDC, PVC, or polyacrylates are particularly used as shell materials. Hydrocarbons of the lower alkanes, for example, isobutane or isopentane, are particularly suitable as low-boiling liquids, which are enclosed in the polymer shell as a liquefied gas under pressure.

[0036] When exposed to external influences, particularly heat, the outer polymer shell softens. At the same time, the liquid propellant gas contained within the shell transforms into a gaseous state. The microballoons expand irreversibly and expand three-dimensionally. The expansion is complete when the internal and external pressures equalize. Because the polymer shell remains intact and / or the surrounding, now cross-linked polymer stabilizes the cavity, a closed-cell foam is achieved. When foaming is performed using microballoons, the microballoons can be added to the formulation as a batch, paste, or as an unblended or blended powder.

[0037] A variety of microballoon types are commercially available, differing primarily in their size (6 to 45 µm diameter in the unexpanded state) and the initial temperatures required for expansion (75 to 220°C). Examples of commercially available microballoons are the Mikropearls from Lehmann & Voss or the Expancel® from Nouryon.

[0038] In a further aspect of the invention, the foamed carrier according to the invention is produced with pre-expanded microballoons. In this group, the expansion takes place before mixing into the polymer matrix. Pre-expanded microballoons are commercially available, for example, under the name Mikropearls FE (Lehmann & Voss) or with the type designation DE (Nouryon).

[0039] The density of a foamed carrier according to the invention is between 100 and 1000 kg / m 3 , preferably between 400 and 800 kg / m 3 . Anti-aging agents:

[0040] To stabilize the pressure-sensitive adhesive against aging, primary antioxidants such as sterically hindered phenols and / or secondary antioxidants such as phosphites or thioethers and / or C radical scavengers are advantageously added.

[0041] Antioxidants prevent oxidative degradation of polymers at higher temperatures or during prolonged exposure to high temperatures. This can provide protection both during the manufacturing process and during use and the product's lifetime. Antioxidants can be purchased from BASF, for example, under the brand name Irganox.

[0042] Liquid antioxidants are advantageously used due to their better miscibility at room temperature. The addition rate is between 0.1 and 3% by mass, based on the total amount of the mixture. UV protection agents:

[0043] Advantageously, at least one UV protectant is added to protect against UV radiation.

[0044] UV protectants known to those skilled in the art can be used. UV protectants can be purchased, for example, from BASF under the brand name Tinuvin. The addition rate is 0.1 to 3% by mass, based on the total amount of the mixture. Dyes:

[0045] Without additional fillers and dyes, the carriers according to the invention are white in color due to the foaming agents. However, colored carriers are also according to the invention. For this purpose, dyes or color pigments are mixed into the mixture to be coated. For a black color, for example, carbon black-based dyes can be added. The corresponding color shade is created depending on the amount added. The amount added must be adjusted to the desired color impression. The skilled person selects known dyes and pigment preparations as dyes. Attention must be paid to solubility and compatibility with the polymer mixture. Advantageously, dyes that are easily soluble in the SMP and do not hinder the crosslinking process, for example, liquid dyes or dye preparations, are used. For example, the Bayderm range from Lanxess.The amount added for a black color, for example, is between 1 and 5% by weight, based on the total amount of the mixture.

[0046] Other dyes or dye preparations from the state of the art are also conceivable. Other ingredients:

[0047] The carrier according to the invention can also contain tackifying resins. Tackifying resins can be incorporated into the mixture prior to coating. This results in the carriers exhibiting higher tack and higher adhesive strength. All resins known in the art can be used as tackifying resins. However, care must be taken to ensure they are compatible with the polymer mixture. Resins from the groups of hydrocarbon resins, terpene resins, and rosin resins, as well as their derivatives / modifications / hydrogenations, are possible. Terpene-phenolic resins have proven particularly suitable. They are available from DRT (Dertophen) and Kraton (Sylvares).

[0048] The carrier according to the invention can contain, as further components, for example, powdered and granular fillers, especially abrasive and reinforcing fillers, dyes, and pigments such as titanium dioxide, zinc oxides, and / or carbon black. Carbonates (calcium carbonates, magnesium carbonates, and mixtures) and metal oxides or hydroxides are often used in SMP. They lead to an increase in the internal strength of the polymer mixtures after curing.

[0049] In addition, various organic fillers may be included.

[0050] Further suitable additives for the supports according to the invention are also - independently selected from other additives - non-expandable hollow polymer spheres, solid polymer spheres, hollow glass spheres, solid glass spheres, hollow ceramic spheres and / or solid ceramic spheres.

[0051] Furthermore, the foamed carrier according to the invention may also contain: - flame-retardant fillers, for example ammonium polyphosphate or aluminium hydroxide; - electrically conductive fillers, for example conductive carbon black, carbon fibers and / or silver-coated spheres; - thermally conductive materials such as boron nitride, aluminum oxide, aluminum hydroxide, silicon carbide; ferromagnetic additives, for example iron(III) oxidesM; - organic, renewable raw materials such as wood flour, organic and / or inorganic nanoparticles; - Fibers, compounding agents and / or antiozonants.

[0052] Plasticizers may optionally be included. Examples of plasticizers that can be added include acrylate oligomers, phthalates, water-soluble plasticizers, plastic resins, phosphates, polyphosphates, adipates, citrates, and / or polyether compounds.

[0053] The addition of hydrophilic or hydrophobic silica, advantageously precipitated silica, can be used to adjust the internal strength, the viscosity before coating or the thermal shear strength.

[0054] All raw materials in the mixture must be selected so that they do not adversely alter the main crosslinking reaction. For example, anhydrous or low-water raw materials should be used wherever possible to prevent premature or partial onset of the hydrolysis reaction. Manufacturing process:

[0055] The mixture is manufactured by first mixing the components of the mixture homogeneously. The SMP polymers are liquid at room temperature, so the mixing process can take place at room temperature. The mixing process can also take place under standard atmosphere; an anhydrous protective atmosphere is not necessary before adding the catalyst. The polymers are sufficiently stable. After adding the catalyst (by stirring in), the reactivity increases. In the presence of atmospheric moisture, the crosslinking reaction begins. This results in an increase in viscosity and, subsequently, skin formation and gelling of the mixture. Therefore, coating must either take place soon after adding the catalyst, or the mixture must be protected from atmospheric moisture by suitable measures (protective gas, atmosphere with reduced humidity). The addition of water scavengers can also extend the coatability time of the mixture, the so-called pot life.However, this also extends the subsequent curing time.

[0056] When preparing the mixture, care must be taken to ensure that little air is introduced and that the air bubbles are removed by allowing it to stand or, in the case of high viscosities, by degassing under vacuum.

[0057] The coating is applied to a siliconized polyester film using a doctor blade. The siliconization must be selected and adjusted so that the polyester film can be easily removed later, i.e., excessive adhesion to the cured mixture is avoided. Polymers containing alkoxysilanes can also interact or react with the silicone layer of the polyester film, reducing the repellent effect of the silicone layer. This depends on the type of polymer, the type of silicone layer, and also the type and amount of catalyst.

[0058] Two layers are coated for a carrier, which are then laminated to each other with the open sides facing each other after removal from the oven. This has the advantage of creating a carrier with two smooth outer layers: while the individual patterns can be structured on the open side, they then form a smooth surface on the side facing the polyester film.

[0059] The thickness of the layers depends on the target thickness of the substrate. It should be noted that the thinner the substrate, the faster the crosslinking reaction. Very thick layers have the disadvantage of very long crosslinking times, and crosslinking occurs from the outside in. It may initially be the case that the outer layers are already crosslinked while the inner layers are still liquid. Coating thicknesses of less than 1.0 mm have proven effective.

[0060] The samples are then placed in a convection oven and heated at elevated temperatures, preferably between 110 and 140°C, for 1 to 15 minutes. This causes the foaming agent to foam and the polymers to crosslink. The crosslinking reaction can be further accelerated by adding additional moisture (by humidifying the warm air, using water, or by adding water-releasing additives to the mixture). This allows for lower temperatures and / or shorter treatment times. However, it is preferable to work under normal atmospheres without adding additional moisture or separately humidifying the dry air.

[0061] The samples are then removed from the convection oven and, either immediately or after a brief cooling period, are laminated to each other with the open sides in such a way that the surfaces are in full contact. The surfaces adhere to each other.

[0062] After approximately 24 hours, the liners can be removed, resulting in a carrier pattern with two smooth sides at the top and bottom. Separation of the two original layers is no longer possible, meaning the post-reaction after the oven process has also caused the two layers to bond completely.

[0063] The carriers are slightly to very tacky / sticky. Further embodiments:

[0064] If the coating is applied to unsiliconized or only slightly siliconized films, the result is a single-sided or double-sided film-coated substrate. Suitable films include polyester films, polypropylene films, and other thermoplastic and thermoset films, as long as they are sufficiently temperature-resistant for oven treatment. Temperature-sensitive films can also be laminated to the substrate after the oven treatment, with additional means (adhesive layer, pretreatment) being used to anchor the substrate if the post-cure reaction is insufficient.

[0065] The carriers can also be constructed in additional layers, for example, with film layers in the middle or combined with textile layers (woven, nonwoven, knitted). These additional materials can either be inserted during the coating process, placed between the layers before lamination, or laminated onto the carriers after lamination. The subsequent reaction of the carriers can be used to anchor the additional layers.

[0066] Likewise, in order to achieve thicker supports, the double layers can be laminated to each other after removing the siliconized films so that they anchor together during the post-reaction. Further use for adhesive tapes

[0067] Due to their tack, the backings can also be used as adhesive tapes on their own. Depending on the formulation, adhesive strengths of between 0 and 10 N / 25 mm can be achieved on steel after 24 hours of application. In general, the adhesive strengths are very low, between 0.5 and 3 N / 25 mm. This makes the backings easy to remove from many surfaces, even after extended application times. These are therefore repositionable or removable adhesive tapes.

[0068] To obtain stronger adhesive tapes, the backings must be coated with adhesive layers. All adhesives known to those skilled in the art, their combinations, and coating and lamination processes can be used. The adhesives can be applied to one or both sides. If necessary, the backing can be pretreated by physical or chemical processes to improve the anchoring of the adhesive layers. These can be pressure-sensitive adhesives or structural adhesives. Examples

[0069] The invention will be explained below using exemplary examples. However, this is not to say that the invention is limited to these examples. Rather, many other examples are conceivable for those skilled in the art, such as different thicknesses, the addition of further components as listed in the description, coloring of the foams, or modified process control. Test methodsViscosity:

[0070] The viscosity of the mixtures is measured using a single-point viscosity measurement with the Brookfield RVDV-II+P viscometer. The LV-3 (63) spindle is used. The rotational speed is adjusted to the viscosity range. The result is the viscosity in Pas. Thickness and density:

[0071] The thickness is determined according to ISO 1923. The density is calculated from this and the basis weight according to ISO 845. Tensile strength and elongation at break:

[0072] Tensile strength and elongation at break are determined according to ISO 1926 in the longitudinal direction (coating direction, stroke direction). The bone mold has a web width of 6 mm, and the thickness is the sample thickness, usually approximately 1 mm. The clamping length is 100 mm, and the tensile speed is 100 mm / min. Tensile strength is the maximum tensile force divided by the product of the web width and sample thickness (in kPa). Elongation at break is the elongation at break in %. Both values ​​are averages of three measurements. Compressive stress-deformation properties (compression hardness)

[0073] The measurement is carried out in accordance with DIN EN ISO 3386-2. The foam is cut into squares of 40 mm × 40 mm. Several foam layers are placed on top of each other to create a thickness of (10 + / - 1) mm. This foam stack is pressed onto the foam sample using a press ram whose surface extends beyond the 40 mm × 40 mm at a speed of 5 mm / min until the stack thickness has been reduced by 25%. The load is then immediately removed and the test specimen returned to zero. The measured values ​​for the compression strength are taken at 10% and 25% reductions in the stack thickness. The compression strength is calculated from the quotient of the required force and the area (1600 mm 2 ) and is expressed in kPa. Shore hardness

[0074] The measurement is carried out in accordance with DIN ISO 7619 using the digital Shore hardness tester HPE II from Zwick with a measuring head for Shore A hardness. The sample thickness must be at least 6 mm. Thinner foams are stacked in multiple layers until the required total thickness is reached. Water vapor permeability:

[0075] The water vapor permeability of the foams is measured in accordance with DIN EN 13726-2 at a temperature of 37°C and a relative humidity of 20%. The carriers are measured in a single layer. A single determination was performed. Bending test at -40° C:

[0076] To assess the foams' resistance to low temperatures, a bending test and a tack test are conducted at -40°C. Strips of each foam, measuring 25 mm × 50 mm, are conditioned at -40°C for 3 hours. The test specimens are then bent at -40°C (up to 180°C) and assessed for their flexibility or for breaking (resulting in breaking). A finger is also used to determine whether the foams are tacky (sticky) at -40°C. Temperature resistance at 125°C

[0077] To assess resistance to high temperatures, a shrinkage test is carried out at 125°C. The shrinkage or change in the foam (3 samples measuring 25 mm × 50 mm) is assessed after storage at 125°C for 24 hours. Peel strength:

[0078] The 180° peel strength is measured in accordance with DIN ISO 1939 under standard conditions (23°C, 50% relative humidity). Stainless steel serves as the substrate (according to Afera Standard 4001). The foam strip is 25 mm wide. The backing is reinforced with a thin, stretch-free adhesive tape to prevent the test strip from stretching during peeling. The peeling time is 24 hours under standard conditions (23°C, 50% relative humidity). The peel angle is 180°. The stated value is the average of three measurements. Raw materials used: Designation Manufacturer Description SAX 510 Kaneka Belgium NV Linear MS polymer, TMS SAX 580 Kaneka Belgium NV Branched MS polymer, TMS SAX 015 Kaneka Belgium NV Branched MS polymer, DMS SAT 145 Kaneka Belgium NV Linear MS polymer, DMS S 327 Kaneka Belgium NV Linear MS polymer, DMS Q-CEL 5028 Omega Minerals Hollow glass spheres, average diameter 60 µm Microbeads F-36 Lehmann & Voss Expandable microbeads, at approx. 100°C Microbeads F-48 Lehmann & Voss Expandable microbeads, at approx. 120°C Geniosil XL 10 Wacker AG Silane, vinyltrimethoxysilane Tyzor TnBT Dorf Ketal Chemicals Titanium tetrabutoxide Irganox 1135 BASF SE Anti-aging agents Tinuvin 292 BASF SE UV protectants Bayderm black BO Lanxess Carbon black paste, colorant

[0079] In recipes, “parts” always mean parts by weight. Example 1 (B1):

[0080] 94 parts of SAX 510 are placed in a mixing bowl and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292, 0.6 parts of Irganox 1135, and 0.3 parts of Geniosil XL 10 are added. Then, while stirring, 1.7 parts of Microbeads F-48 and 2.5 parts of Bayderm Black BO are added. The mixture is stirred until homogeneous.

[0081] Shortly before coating, 0.75 part of Tyzor TnBT is added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 20 Pas. It is coated within 10 minutes to prevent premature gelling.

[0082] The coating is applied to a siliconized polyester film using a doctor blade. The gap size is 600 µm. The doctor blade is moved at a speed of 1 m / min. Two such layers are applied to the polyester film. Both samples are cured simultaneously in a convection oven at 130°C for 5 minutes.

[0083] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The resulting sample is then stored at 23°C, covered on both sides, for at least 72 hours.

[0084] For the tests (in all examples) the two siliconized polyester films are removed and a foam with two smooth surfaces is obtained. Example 2 (B 2):

[0085] 96 parts of SAX 510 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292, 0.6 parts of Irganox 1135, and 0.3 parts of Geniosil XL 10 are added. Then, while stirring, 1.7 parts of F-48 microbeads are added. The mixture is stirred until homogeneous.

[0086] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 20 Pas. It is coated within 7 minutes.

[0087] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 5 minutes at 130°C.

[0088] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 3 (B 3):

[0089] 96 parts of SAX 580 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292, 0.6 parts of Irganox 1135, and 0.3 parts of Geniosil XL 10 are added. Then, while stirring, 1.7 parts of F-48 microbeads are added. The mixture is stirred until homogeneous.

[0090] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 20 Pas. It is coated within 5 minutes.

[0091] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 5 minutes at 130°C.

[0092] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 4 (B 4):

[0093] 96 parts of MS-Polymer S 327 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 1.7 parts of Microbeads F-48 are added. The mixture is stirred until homogeneous.

[0094] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 21 Pas. It is coated within 10 minutes.

[0095] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 10 minutes at 130°C.

[0096] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 5 (B 5), not according to the invention:

[0097] 98 parts of MS-Polymer S 327 are placed in a mixing bowl and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. No foaming agent is added. The mixture is stirred until homogeneous. Shortly before coating, 0.78 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 20 Pas. It is coated within 10 minutes to prevent premature gelling.

[0098] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 10 minutes at 130°C.

[0099] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 6 (B 6):

[0100] 88 parts of MS-Polymer S 327 and 9 parts of SAT 145 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 1.7 parts of F-48 microbeads are added. The mixture is stirred until homogeneous.

[0101] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 18 Pas. It is coated within 15 minutes.

[0102] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 15 minutes at 130°C.

[0103] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 7 (B 7):

[0104] 86 parts of MS-Polymer S 327 and 8 parts of SAT 145 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 1.7 parts of Microbeads F-48 and 2.5 parts of Bayderm black BO are added. The mixture is stirred until homogeneous.

[0105] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 18 Pas. It is coated within 15 minutes.

[0106] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 15 minutes at 130°C.

[0107] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 8 (B 8):

[0108] 79 parts of MS-Polymer S 327 and 17 parts of SAT 145 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 1.7 parts of Microbeads F-48 are added and stirred until homogeneous.

[0109] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 16 Pas. It is coated within 15 minutes.

[0110] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 15 minutes at 130°C.

[0111] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 9 (B 9):

[0112] 88 parts of MS-Polymer S 327 and 9 parts of SAX 015 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 1.7 parts of Microbeads F-48 are added and stirred until homogeneous.

[0113] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 16 Pas. It is coated within 15 minutes.

[0114] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 15 minutes at 130°C.

[0115] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 10 (B 10):

[0116] 94 parts of MS-Polymer S 327 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, 4.1 parts of Q-CEL 5028 are added and stirred until homogeneous.

[0117] Shortly before coating, 0.75 part of Tyzor TnBT is added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 22 Pas. It is coated within 15 minutes.

[0118] Coating of two samples is carried out as in Example 1. The gap size is 600 µm. Storage in a convection oven is 15 minutes at 130°C.

[0119] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 11 (B 11):

[0120] 87 parts of MS-Polymer S 327 and 8 parts of SAT 145 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 2.3 parts of F-48 microbeads are added. The mixture is stirred until homogeneous.

[0121] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 22 Pas. It is coated within 15 minutes.

[0122] Two samples are coated with a gap size of 600 µm. They are stored in a convection oven for 10 minutes at 130°C.

[0123] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 12 (B 12):

[0124] 89 parts of MS-Polymer S 327 and 9 parts of SAT 145 are mixed and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 0.9 parts of Microbeads F-48 are added. The mixture is stirred until homogeneous.

[0125] Shortly before coating, 0.77 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 20 Pas. It is coated within 15 minutes.

[0126] Two samples are coated with a gap size of 600 µm. They are stored in a convection oven for 10 minutes at 130°C.

[0127] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 13 (B 13):

[0128] 87 parts of MS-Polymer S 327 and 8 parts of SAT 145 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 2.3 parts of Microbeads F-36 are added. The mixture is stirred until homogeneous.

[0129] Shortly before coating, 0.77 parts of Tyzor TnBT are added and stirred until homogeneous. The mixture has a viscosity of approximately 21 Pas. It is coated within 15 minutes.

[0130] Two samples are coated with a gap size of 600 µm. They are stored in a convection oven for 5 minutes at 130°C.

[0131] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Example 14 (B 14):

[0132] 87 parts of MS-Polymer S 327 and 8 parts of SAT 145 are added and stirred with a paddle stirrer. While stirring, 0.6 parts of Tinuvin 292 and 0.6 parts of Irganox 1135 are added. Then, while stirring, 1.7 parts of Microbeads F-48 are added. The mixture is stirred until homogeneous.

[0133] Shortly before coating, 1.53 parts of Tyzor TnBT are added and the mixture is stirred until homogeneous. The mixture has a viscosity of approximately 20 Pas. It is coated within 10 minutes.

[0134] Two samples are coated with a gap size of 600 µm. They are stored in a convection oven for 5 minutes at 130°C.

[0135] Immediately after removal from the convection oven, the samples are laminated with the open sides facing each other. The samples are then stored at 23°C, covered on both sides, for at least 72 hours. Comparison example 1 (VB1):

[0136] This is a commercially available foam from Sekisui Alveo AG based on polyethylene called Alveolit ​​TE 1501. Its thickness is 1 mm and its density is 67 kg / m 3 . Comparison example 2 (VB 2):

[0137] This is the commercially available foam Alveolit ​​TMA SRZ 801 from Sekisui Alveo AG. Its thickness is 1 mm and its density is 125 kg / m 3 , color black. Comparison example 3 (VB 3):

[0138] This is the acrylic foam GT 6008 from 3M Deutschland GmbH. Its thickness is 0.8 mm and its density is 700 kg / m 3 . Results test Unit B1 B2 B3 B4 B5 B6 B7 thickness µm 1095 1070 1080 1120 820 1350 1300 Basis weight g / m 2 765 773 770 774 804 768 765 density kg / m 3 699 722 713 691 981 569 588 Tensile strength longitudinal kPa 279 296 386 382 359 321 282 Elongation at break longitudinally % 65 82 41 106 130 120 147 Compressive strength at 10% kPa 22 104 156 109 89 32 31 Compressive strength at 25% kPa 153 386 460 312 353 115 108 Shore A hardness 15 18 27 21 14 15 13 Water vapor permeability g / (m 2 *Tag) 286 321 299 270 390 286 286 Bending test at -40°C best ande n best ande n best ande n best ande n best ande n best ande n best ande n Tack at -40°C Yes No Yes Yes Yes Yes Yes Yes Yes Shrinkage at 125°C after 24 h no no no no no no no Peel strength 180° after 24 h N / 25 mm 0,5 0,2 0,0 0,5 0,2 0,4 1,0 Results (continued): test Unit B8 B9 B10 B11 B12 B13 B14 thickness µm 1190 1500 790 1500 1050 1350 1050 Basis weight g / m 2 780 776 630 751 777 758 757 density kg / m 3 655 518 798 501 740 561 721 Tensile strength longitudinal kPa 280 337 401 281 94 267 339 Elongation at break longitudinally % 141 56 81 107 142 99 98 Compressive strength at 10% kPa 17 63 112 80 61 65 102 Compressive strength at 25% kPa 198 217 430 227 171 152 279 Shore A hardness 14 22 21 20 14 14 18 Water vapor permeability g / (m 2 *Tag) 260 286 352 243 317 358 269 Bending test at -40°C best ande n best ande n best ande n best ande n best ande n best ande n best ande n Tack at -40°C Yes No Yes Yes Yes Yes Yes Yes Yes Shrinkage at 125°C after 24 h no no no no no no no Peel strength 180° after 24 h N / 25 mm 0,5 0,4 0,5 9,1 1,0 0,3 0,8 Results (Continued 2) test Unit VB1 VB2 VB3 thickness µm 1000 1000 800 Basis weight g / m 2 67 125 560 density kg / m 3 67 125 700 Tensile strength longitudinal kPa 1094 2589 715 Elongation at break longitudinally % 103 317 583 Compressive strength at 10% kPa 24 67 67 Compressive strength at 25% kPa 50 102 207 Shore A hardness 19 28 10 Water vapor permeability g / (m 2 *Tag) 28 15 220 Bending test at -40°C passed passed breaks Tack at -40°C Yes No no no no Shrinkage at 125°C after 24 h shrinks and melts shrinks and melts no Peel strength 180° after 24 h N / 25 mm 0,0 0,0 68,0

[0139] The results of the shrinkage test show that the thermal stability of the inventive supports at high temperatures is much better than that of the PE foams. The PE foams (VB1 and VB2) not only shrink at 125°C, they actually melt, as the melting temperature is exceeded. The inventive supports are stable. The results of the flexural test at -40°C again show the inventive supports to be stable, i.e., flexible, whereas the acrylic foam VB3 breaks at this temperature. It is brittle because its glass transition temperature is too high. Thus, the inventive supports can be used over a wider temperature range than previously known ones.

[0140] The water vapor permeability of examples B1 to B14 is much higher than that of the comparative examples.

[0141] Peel strength measurements show that the inventive backings have low tack properties and thus wet surfaces well upon application. They can therefore be used (without an additional adhesive layer) for applications requiring light wetting and removable bonding or blocking.

[0142] The hardness of the inventive backings (compression hardness, Shore hardness) can be varied by formulation. The backing densities are above the typical densities for polyolefin foams and within the range of those for acrylate foams. The tensile strengths and elongation at break are below those of the comparative examples. The haptic properties (softness, flexibility, blocking) are similar to those of silicone films of this thickness.

Claims

[1] Use of a mixture for producing carriers for adhesive tapes, comprising at least one chain-shaped or branched silane-modified, alkoxysilated prepolymer, at least one foaming agent and at least one catalyst, wherein when using a plurality of prepolymers these are crosslinked with each other with elimination of alcohol, wherein the carrier is a foamed carrier and wherein the foaming agents are hollow glass spheres, expandable or pre-expanded microballoons, wherein the mixture is composed at least of 40 - 99 % silane-modified alkoxylated prepolymers, 0 - 10 % foaming agent and 0.1 - 5% catalyst, where the proportions are to be understood as weight proportions and add up to 100%, wherein the mixture contains 0.1 to 3%, based on the total formulation, of at least one anti-aging agent and 0.1 to 3%, based on the total formulation, of at least one UV protection agent and whose water vapor permeability is greater than 200 g / (m 2 *d). [2] Use of a mixture according to claim 1, wherein the silane-modified alkoxylated prepolymers are polyurethanes and / or polyethers with groups of mono-, di- or trialkoxysilanes, preferably polyethers with groups of di- or trimethoxysilanes. [3] Use of a mixture according to any one of the preceding claims, wherein the carrier has a density between 100 and 1000 kg / m 3 , preferably between 400 and 850 kg / m 3 has. [4] Use of a mixture according to at least one of the preceding claims, wherein its compression hardness at 10% compression is less than 200 kPa. [5] Use of a mixture according to at least one of the preceding claims characterized by that the adhesive tape carrier is produced by coating the mixture onto at least one web-shaped carrier and then crosslinking and foaming at a temperature greater than 60°C. [6] Use of a mixture according to at least one of the preceding claims characterized by that the carrier is formed from one layer. [7] Use of a mixture according to at least one of the preceding claims characterized by that the carrier is formed from two layers, with the two layers being coated and foamed separately before being laminated to each other with the open side facing each other.