Release coating with low friction coefficient

Abstract

The invention concerns a release coating for furnishing a release liner, comprising • a release agent and • 0.01% to 30% by weight, based on the total weight of the release coating, of three-dimensional elements K and being characterized in that the elements K contain in total at least 90% by weight of one or more polysaccharides. The invention further concerns the use of such a release coating in release liners or on reverse sides of adhesive-tape carriers and also release liners equipped therewith and the use thereof in adhesive tapes.

Description

[0001] Description

[0002] Release coating with low friction coefficient

[0003] The invention relates to the technical field of release coatings, such as those used as anti-adhesive coatings for release liners or adhesive tape backings. More specifically, the invention proposes a release coating with a low coefficient of friction.

[0004] Adhesive tapes coated with adhesives on one or both sides are usually wound into a roll in the shape of an Archimedean spiral at the end of the manufacturing process. To prevent the adhesives from coming into contact with each other in the case of double-sided adhesive tapes, or to ensure easier unwinding in the case of single-sided adhesive tapes, the adhesive is covered with a release liner (also known as a release material) before the tape is wound. Such release liners are known to those skilled in the art as "release liners" or "liners." In addition to covering single- or double-sided adhesive tapes, liners are also used to cover labels.

[0005] These release liners also ensure that the adhesive is not contaminated before application. In addition, release liners can be adjusted by the type and composition of the release materials so that the tape can be unrolled with the desired force (light or heavy). For adhesive tapes coated on both sides, the release liners also ensure that the correct side of the adhesive is exposed first during unrolling.

[0006] A liner or release liner is not a component of an adhesive tape or label, but merely an aid for their production, storage, or further processing by die-cutting. Furthermore, unlike an adhesive tape backing, a liner is not permanently bonded to an adhesive layer. Industrially, release liners are typically paper or film backings coated with an abhesive coating compound (also known as a dehesive or anti-adhesive compound) to reduce the tendency of adhering products to adhere to these surfaces (release function). A variety of different substances can be used as such compounds, which are also called release materials: waxes, fluorinated or partially fluorinated compounds, and especially silicones, as well as various copolymers containing silicone components.In recent years, silicones have become widely accepted as release materials in the field of adhesive tape applications due to their good processability, low costs and broad property profile.

[0007] A series of adhesive tapes, coated on both sides with adhesive, are unrolled and applied with the release liner included in the product covering the second adhesive. During manual application, the adhesive of the tape is brought into contact with the substrate by brushing over the release liner with the hand. This application, carried out under pressure, results in strong contact between the release liner of the tape and the hand. Due to the release material used, the predominantly used release liners have a dull surface with a high coefficient of friction. In this case, brushing the product can be uncomfortable or even painful – especially if done frequently and / or at high speed.

[0008] It is known that the coefficient of friction of silicone release coatings can be reduced by various methods, but all of these methods have certain disadvantages.

[0009] Unmodified silicone systems, such as those formed by crosslinking functionalized siloxanes, exhibit very good release properties but a high coefficient of friction. When silicone condensation systems are used instead of the predominantly industrially used silicone addition systems, the coefficient of friction is somewhat lower. However, these condensation systems almost exclusively use toxic tin catalysts.

[0010] Those skilled in the art know that reducing the thickness of the release coating can reduce friction. However, this often leads to an undesirable deterioration in the release properties. Accordingly, the thickness of the release coating cannot be reduced arbitrarily; generally, at least full coverage of the substrate with the release coating must be ensured. For example, with very open-pore paper substrates, this can result in a relatively thick release coating being required just to achieve full coverage.

[0011] The friction coefficient of release systems can also be reduced by adding oils or substances that expand the structures formed during crosslinking of the release system. However, this leads to an increase in the proportion of migratory substances in the release system. These can reduce the adhesive strength by depositing on an adhesive in contact with the release system.

[0012] EP 0 903 385 B1 describes the reduction of friction in radiation-curing silicone systems by adding spherical silicone particles produced by controlled hydrolysis of methyltrimethoxysilane. The complex and inflexible manufacturing process prevents the use of porous or hollow additives, which is particularly advantageous in one aspect of the invention therein.

[0013] US Pat. No. 7,198,854 B describes silicone formulations for treating textile materials to reduce friction and create a glossy appearance. This effect is achieved by adding a mixture of nylon and silica particles. The use of silica particles leads to an undesirable increase in release forces in adhesive tapes.

[0014] US 5,620,775 A describes articles whose coating contains glass spheres with a diameter of 20 to 180 pm to improve reflectivity and friction and to create a hydrophilic surface.

[0015] While spheres with a diameter of 20 pm are clearly too large for use in release films and papers, the creation of hydrophilic surfaces would lead to a significant deterioration in the release behavior of adhesives.

[0016] EP 2 535 389 A1 relates to a composition of a release coating, in particular for equipping a release liner with a layer of the release coating, which:

[0017] • a release agent and • 0.01 wt.% to 30 wt.% (based on the total composition) of a powdered additive in the form of three-dimensional bodies based on polymers made from vinyl building blocks. The release coating exhibits a low coefficient of friction, but the added polymer particles are increasingly viewed with concern in connection with the release of "microplastics" into the environment.

[0018] An object of the present invention was to provide release layers that combine a low coefficient of friction with stable, low release values.

[0019] A further object of the present invention was to provide release coatings which, when used in adhesive tapes, show only a very slight, ideally no, reduction in adhesive strength due to transfer of some components of the release coating to the adhesive after contact.

[0020] A further objective of the invention was to design the separating layers in such a way that they are toxicologically safe and, as far as possible, also meet sustainability requirements, particularly with regard to microplastics. Furthermore, the separating layers should be easy to handle in terms of process technology.

[0021] A first and general subject of the invention with which these objects are achieved is a release coating for equipping a release liner, which

[0022] • a release agent and

[0023] • 0.01 wt.% to 30 wt.%, based on the total weight of the release coating, of three-dimensional bodies K, and is characterized in that the bodies K contain at least 90 wt.% of one or more polysaccharides

[0024] According to a first advantageous embodiment of the invention, the release coating consists only of the release agent and the three-dimensional bodies K.

[0025] A "three-dimensional body" is a three-dimensional, bounded geometric shape that can be described by interfaces. A geometric shape is said to be three-dimensional if it is not completely contained in any plane, and bounded if there is a sphere that completely contains this shape. The most well-known bodies have flat, circular, or spherical interfaces. Such bodies can be cylinders, cones, spheres, prisms, pyramids, tetrahedra, cubes, and / or the five regular polyhedra. If a body is bounded exclusively by flat surfaces, it is called a polytope or a bounded polyhedron.

[0026] In one embodiment, the bodies K may have one or more of the following shapes:

[0027] • Spat with the special cases cuboid and hexahedron (cube)

[0028] • Prism with the generalization cylinder and the special cases cuboid and hexahedron

[0029] • Pyramid with the generalization cone and the special case tetrahedron

[0030] • Antiprism with the special case of octahedron.

[0031] The bodies K, especially in the above-mentioned shapes, such as cubes, preferably have no corners or sharp edges. For this purpose, the existing corners or edges can be rounded. The bodies K are preferably ellipsoids, particularly preferably rotational ellipsoids, and especially spheres.

[0032] According to the invention, the bodies K preferably have a D50 value of the volumetric particle size distribution, determined by means of laser diffraction as described herein, of at most 15 pm, particularly preferably at most 13 pm, in particular at most 12 pm. The D90 value of the volumetric particle size distribution of the bodies K, determined by means of laser diffraction as described herein, is preferably at most 30 pm, particularly preferably at most 27 pm, in particular at most 25 pm. A "diameter of the bodies K" is understood to mean a straight line that connects two points on the surface of a body and passes through the center of this body.

[0033] Particularly preferred

[0034] - the bodies K are rotational ellipsoids and

[0035] - the bodies K have a D50 value of the volumetric particle size distribution of a maximum of 12 pm.

[0036] More preferably, the length of the smallest diameter of the bodies K deviates from the length of the largest diameter by a maximum of 20%, particularly preferably by a maximum of 10%. A "diameter of the bodies K" is understood to be a straight line that connects two points on the surface of a body and passes through the center of this body. As already described, the bodies K are most preferably spheres. In an ideal sphere, the lengths of the largest and smallest diameters are identical. Minor deviations from the ideal spherical shape do not prevent the bodies from being classified as "spheres."

[0037] The bodies K can in principle be solid bodies, hollow bodies or porous bodies; they are preferably solid bodies.

[0038] According to the invention, the bodies K contain at least 90% by weight of one or more polysaccharides. Preferably, the bodies K contain at least 92% by weight of one or more polysaccharides, more preferably at least 95% by weight of one or more polysaccharides, and in particular at least 98% by weight of one or more polysaccharides. Most preferably, the bodies K consist of one or more polysaccharides.

[0039] The one or more polysaccharides are preferably selected from cellulose and starch. The bodies K thus preferably contain at least 90% by weight of one or more polysaccharides selected from cellulose and starch. More preferably, the bodies K contain at least 92% by weight, particularly preferably at least 95% by weight, and in particular at least 98% by weight, of one or more polysaccharides selected from cellulose and starch. Most preferably, the bodies K consist of one or more polysaccharides selected from cellulose and starch.

[0040] Cellulose- and / or starch-based K bodies are particularly characterized by their ease of production in the required particle sizes and their high resistance to silicone systems, which are often used as the basis for release coatings. For example, they have proven highly resistant to temperatures of up to 170 °C, which are typically encountered during the crosslinking of silicone systems.

[0041] Starch-containing or starch-containing bodies K are preferably based on starch from potatoes, corn or rice.

[0042] Cellulose-containing or cellulose-containing bodies K preferably comprise so-called microcrystalline cellulose. In a preferred embodiment of the invention, the bodies K are cellulose or starch spheres with a D50 value of the volumetric particle size distribution of a maximum of 12 pm.

[0043] A significant disadvantage of various conventional, plastic-based release layer additives is that the particles partially detach from the release layer composite when the release liner is applied, unless they are fixed in the release layer—for example, through crosslinking. This can lead to the release of "microplastics." While the three-dimensional bodies K of the present invention can also detach from the release layer composite, the particles would be toxicologically safe and biodegradable in this case, making them preferable to conventional additives, especially from a sustainability perspective.

[0044] The incorporation of the K bodies into the release coating composition is preferably carried out using a device selected from the group consisting of a paddle stirrer, a dispersing disk, and an inline dispersing machine; particularly preferably, it is carried out using a dispersing disk or an inline dispersing machine. These two devices are particularly effective at preventing unwanted agglomeration of the K bodies.

[0045] In principle, any system known to the person skilled in the art can be used as a release agent. The release agent is preferably selected from the group consisting of silicones, fluorinated silicones, silicone copolymers, waxes, carbamates, and mixtures of two or more of the aforementioned materials.

[0046] The release agent may comprise solvent-based and / or solvent-free systems, with solvent-free systems being preferred.

[0047] The release agent can be radiation-crosslinking (UV or electron beam), condensation-crosslinking or addition-crosslinking, preferably it is addition-crosslinking.

[0048] The release agent is particularly preferably a crosslinked silicone. In the uncrosslinked state, it therefore preferably contains a mixture of one or more crosslinking catalysts and one or more thermally curable, condensation- or addition-crosslinking polysiloxanes. For condensation-curing silicone systems, tin compounds such as dibutyltin diacetate are often included as crosslinking catalysts.

[0049] Silicone-based release agents based on addition curing can be cured by hydrosilylation. These release agents typically contain the following components:

[0050] • an alkenylated polydiorganosiloxane, in particular a linear polymer with terminal alkenyl groups,

[0051] • a polyorganohydrogensiloxane crosslinking agent and

[0052] • a hydrosilylation catalyst.

[0053] Platinum or platinum compounds such as the Karstedt catalyst (a Pt(O) complex compound) have become particularly popular as catalysts for addition-curing silicone systems (hydrosilylation catalysts).

[0054] Other silicone systems that can be used include photoactive catalysts, so-called photoinitiators, in combination with UV-curable, cationically crosslinking siloxanes based on epoxy and / or vinyl ethers, or UV-curable, radically crosslinking siloxanes such as acrylate-modified siloxanes. Electron-beam-curable silicone acrylates can also be used. Depending on the intended use, the silicone systems can also contain other additives such as stabilizers or flow control agents.

[0055] Photopolymerizable organopolysiloxane compositions can also be used. Examples include compositions that are crosslinked by the reaction between organopolysiloxanes containing hydrocarbon radicals substituted with (meth)acrylate groups and directly bonded to the silicon atoms, and in the presence of a photosensitizer (see EP 0 168 713 B1 or DE 38 20 294 C1). Also usable are compositions in which the crosslinking reaction occurs between organopolysiloxanes containing silicon-bonded hydrocarbon radicals substituted with mercapto groups and organopolysiloxanes containing vinyl groups directly bonded to the silicon atoms in the presence of a photosensitizer. Such compositions are described, for example, in US Pat. No. 4,725,630 A1.

[0056] When using the organopolysiloxane compositions described, for example, in DE 33 16 166 C1, which contain silicon-bonded hydrocarbon radicals substituted with epoxy groups, the crosslinking reaction is induced by the release of a catalytic amount of acid obtained by photodecomposition of onium salt catalysts. Other organopolysiloxane compositions curable by a cationic mechanism are materials containing, for example, propenyloxysiloxane end groups.

[0057] According to a particularly advantageous embodiment of the invention, the release coating has the following, completely homogenized composition:

[0058] • 92.5 to 99.5 wt.% of an addition-cured silicone system based on a vinyl-functionalized polysiloxane, a methylhydrogensiloxane and a platinum catalyst; and

[0059] • 0.5 to 7.5 wt.% of rotational ellipsoids in which the length of the largest diameter deviates by a maximum of 10% from the length of the smallest diameter, in particular spheres, made of cellulose and / or starch.

[0060] The invention further provides for the use of a release coating according to the invention as at least one outer layer of a release liner or as a backing coating of an adhesive tape carrier. “Outer layer” and “backing coating” mean that one side of the layer in question is exposed; in particular, this side is oriented outward, i.e., away from the other constituents of the release liner or adhesive tape, and is intended for direct contact with a (pressure-sensitive) adhesive. For this purpose, the release coating according to the invention can be applied to a carrier material, preferably as a continuous layer. Preferably, a release liner is provided on both sides with a release coating according to the invention within the scope of the inventive use.

[0061] If the release coating is silicone-based, the silicone system underlying the release coating according to the invention can be applied to a carrier solvent-free or from solution to produce a release liner or a backing-releasing adhesive tape. In principle, all coating methods familiar to the person skilled in the art can be used. The silicone system can then be dried if necessary. The release coating according to the invention preferably has a layer thickness of 0.1 to 5.0 μm, more preferably 0.2 to 2.5 μm, in particular 0.4 to 2.0 μm, within the scope of the inventive use.

[0062] Papers or films can be used, in particular, as the carrier material for the release liner. Films made of biaxially oriented polyethylene terephthalate, polybutene, polypropylene, polyethylene, monoaxially oriented polypropylene, biaxially oriented polypropylene, or polyethylene are preferred. Particularly preferred are polyolefin films, especially polypropylene or polyethylene films, or polyester films.

[0063] A further subject matter of the invention is, in accordance with the above, a release liner comprising a carrier film and a release coating according to the invention.

[0064] The invention further provides a single-sided adhesive tape comprising a carrier material having a first and a second side and a pressure-sensitive adhesive on the first side of the carrier material and a release coating according to the invention on the second side of the carrier material.

[0065] The invention further relates to the use of a release coating according to the invention, preferably based on silicone, as at least one outer layer of a release liner with which a single- or double-sided adhesive tape is covered on one or both sides. Typically, a single-sided adhesive tape is covered with a release liner on the adhesive side. For a double-sided adhesive tape, one release liner may be sufficient, but both adhesive sides can also be coated with a release liner each.

[0066] The adhesive in an adhesive tape is usually, and preferably according to the invention, a pressure-sensitive adhesive. Pressure-sensitive adhesives are adhesives that allow a permanent bond to the substrate even under relatively light pressure. Pressure-sensitive adhesives are permanently tacky at room temperature, meaning they have a sufficiently low viscosity and high tackiness, allowing them to wet the surface of the respective substrate even under light pressure. The bondability of pressure-sensitive adhesives is based on their adhesive properties, while their more or less pronounced removability is based on their cohesive properties.

[0067] Various compounds can be used as a basis for pressure-sensitive adhesives.

[0068] The polymer base of the pressure-sensitive adhesive is preferably selected from the group consisting of poly(meth)acrylates; silicones; natural rubber; and synthetic rubbers, in particular styrene block copolymers with an elastomer block composed of unsaturated or hydrogenated polydiene blocks, for example, polybutadiene, polyisoprene, copolymers of both, and other elastomer blocks familiar to the person skilled in the art. The pressure-sensitive adhesive may comprise a combination of several base polymers and, in addition to the base polymer(s), may contain, for example, tackifier resins, plasticizers, fillers, pigments, UV absorbers, light stabilizers, anti-aging agents, and / or crosslinkers, as well as optionally further additives.

[0069] The carrier, or in the case of so-called transfer adhesive tapes, the liner of the adhesive tape, can be coated on one side with the pressure-sensitive adhesive from a solution, dispersion, 100% (e.g., from the melt), or by coextrusion. Alternatively, coating is possible by transferring a pressure-sensitive adhesive layer using lamination. The adhesive layer can be crosslinked using heat or high-energy radiation.

[0070] The application weight of the pressure-sensitive adhesive layer is preferably 10 to 120 g / m 2 , more preferably 25 to 100 g / m 2 , which refers to the weight after any necessary removal of water or solvent. Those skilled in the art are aware that the numerical values ​​of the application weight also roughly correspond to the layer thickness in pm.

[0071] Physical pretreatment of the carrier side to be coated with the pressure-sensitive adhesive to improve adhesion, for example, by flame, plasma, or corona treatment, can be advantageous. Alternatively or additionally, a primer layer, particularly solvent-free, such as by coextrusion, can be applied before the pressure-sensitive adhesive layer is applied to the carrier, so that a primer layer is present between the carrier layer and the pressure-sensitive adhesive layer.

[0072] Known dispersion and solvent systems can be used as primers, for example, those based on isoprene- or butadiene-containing rubbers and / or cyclic rubbers. Isocyanates or epoxy resins as additives improve adhesion and, in some cases, also increase the shear strength of the pressure-sensitive adhesive. The invention also relates to the use of a release liner according to the invention in an adhesive tape used for bonding paper or film webs.

[0073] Flat, web-like materials, especially paper, are often wound into bales in industrial applications, which are then fed into paper processing machines, printing machines, or packaging machines, for example. During continuous operation of such systems, it is necessary to attach the beginning of a new wound bale to the end of the first bale of flat, web-like material on the fly and to join them appropriately, without having to stop the high-speed machines when changing rolls. This process is called splicing.

[0074] For this purpose, the paper industry uses double-sided adhesive tapes, which essentially consist of a carrier layer and two layers of pressure-sensitive adhesive to create a bond between the end of the old material web and the beginning of the new material web. The end of the old material web is bonded to the beginning of the new material web.

[0075] The general term “adhesive tape” in the sense of this invention includes all flat structures such as webs or web sections extended in two dimensions, tapes with extended length and limited width, tape sections, labels, die-cuts and the like.

[0076] Release coatings according to the invention enable the provision of release liners or release-treated adhesive tape backings with a significantly lower coefficient of friction compared to the same system without the bodies K present according to the invention. These additives effectively reduce the friction of the release coatings while maintaining the good release properties against various adhesives.

[0077] Furthermore, it has been shown that the bodies K present in the release coating according to the invention also reduce the adhesive strength depression of a pressure-sensitive adhesive covered with the release system in solvent-based silicone release systems on film carriers. At least in the proportion range of 1 to 8 wt. % of bodies K, a significant decrease in the adhesive strength depression was observed with increasing proportion. The invention therefore further provides a release liner comprising a carrier film and a solvent-based release coating, wherein the release coating contains a release agent and 1 to 8 wt. %, more preferably 2 to 6 wt. %, in each case based on the total weight of the release coating, of three-dimensional bodies K, and the bodies K contain at least 90 wt. % of one or more polysaccharides.All embodiments of the release coating according to the invention or of the release liner according to the invention described herein, insofar as they are applicable to the release liner described in this paragraph, are also considered preferred for this release liner. In particular, the material of the carrier film of the release liner described here is selected from the group consisting of biaxially oriented polyethylene terephthalate; polybutene; polypropylene, in particular monoaxially oriented polypropylene and biaxially oriented polypropylene; and polyethylene. The material of the carrier film is very particularly preferably monoaxially oriented polypropylene (MOPP).

[0078] "Solvent-based release coating" or "solvent-based silicone release system" means that the release system in question is actually applied as a solvent-based system, but after the usually thermally initiated crosslinking, only traces of the solvent remain in the release system. However, experts refer to it as a "solvent-based system" or "solvent-containing system," thus indicating the special properties of such a solvent-based release coating.

[0079] Examples

[0080] Unless otherwise stated, all components are given below in terms of their weight.

[0081] Production and coating of separation systems

[0082] Release liners were produced on a 1300 mm wide KSC 950 white paper (UPM) by applying the release system formulations listed below, with and without additives, using a laboratory coating system. The additives were stirred into the compositions using a paddle stirrer. After coating, the release systems were cured in a convection oven at 160 °C for 30 seconds.

[0083] The liners produced in this way were tested for their coefficient of friction, their release efficiencies compared to the test tapes tesa® 7475 and tesa® 501 10, and their bond strength depression. The test tape tesa® 7475 is a 40 μm thick PVC carrier coated with 95 g / m 2 coated with a resin-modified acrylic pressure-sensitive adhesive. The tesa® 50110 test tape is 300 μm thick and uses a natural rubber pressure-sensitive adhesive on a fabric backing.

[0084] Measurement of separation behavior

[0085] Strips of tesa® 7475 and tesa® 50110 test tapes, each 20 mm wide and 300 mm long, were bonded to the release liners. For each sample, three laminates each consisting of a liner with tesa® 7475 test tape and a liner with tesa® 50110 test tape were stored under pressure and temperature for 24 hours. The storage temperature was 40 °C for the tesa® 50110 test tape and 70 °C for the tesa® 7475 test tape. The pressure in both cases was 4 N / cm. 2 .

[0086] After storing the samples for two hours in an air-conditioned test room at 23 °C and 50% relative humidity, the separation force was determined using a Zwick tensile testing machine. The peel speed was 300 mm / min and the peel angle was 180 °. The results are the average values ​​of the measurements for the three laminates.

[0087] Measurement of adhesive strength depression

[0088] Furthermore, possible transfer of silicone or the various additives was evaluated by measuring the adhesive strength depression of the test tape tesa® 7475. For this purpose, the adhesive strength of a new test tape tesa® 7475 on a steel surface was measured using a tensile test (Zwick tensile testing machine, 300 mm / min, 180°).

[0089] Subsequently, a tesa® 7475 test tape, which had previously been stored with the liner for 24 hours at pressure and temperature to measure its release behavior, was also bonded to steel, and the adhesive strength was measured using a tensile test. The adhesive strength depression is calculated using the following formula: Adhesive strength of fresh tape - Adhesive strength of tape in contact with liner.

[0090] Adhesive strength — Depression 100%

[0091] Adhesive strength of fresh tape Measurement of silicone application

[0092] The coating weight of the separation system was determined by X-ray fluorescence analysis. For this purpose, the carrier coated with the separation system to be investigated was analyzed with the X-ray fluorescence analyzer Lab-X 3000 from Oxford with an internal (polydimethylsiloxane) reference. After excitation with X-rays, the released energy is captured in the form of Si-specific fluorescence radiation and converted stoichiometrically into the coating weight of the silicone separation system in g / m 2 Any false detections due to additives in the carrier material are taken into account by determining a zero value.

[0093] Determination of painting behavior

[0094] To answer the question of whether the release system provides a pleasant skin feel when applied, the samples coated with the release system were evaluated in a direct comparison by five test subjects. The evaluation is based on the skin feel when applying the release system-coated liner by hand under greater pressure – i.e., the usual methods known to those skilled in the art for applying pressure-sensitive adhesives. Only a distinction was made according to

[0095] 1 = pleasant

[0096] 2 = unpleasantly undertaken.

[0097] Silicone system

[0098] Silicone System A is an addition-curing silicone system from Wacker. 9.75 g of DEH 915 (a vinyl-functionalized polydimethylsiloxane) were mixed with 0.33 g of V24 (a methylhydrogenpolysiloxane) and 0.08 g of Kat OL (a platinum catalyst, also known as the "Karstedt catalyst").

[0099] 2.5 wt. % of PMMA spheres (Sepimat® SB, SEPPIC, solid spheres with a size of 1 to 5 μm) or starch spheres (Sepifine® BB, SEPPIC, solid spheres, D50 value of the particle size distribution 11 μm) were added to the silicone system intended for coating the outer surfaces of the liners. The systems intended for the inner surfaces of the liners remained unaddressed. The mixtures were homogenized, applied to the carrier, and then crosslinked as described above. Determination of the particle size distribution

[0100] Particle size distribution was determined using laser diffraction with the Bettersizer S3 Plus device. Deionized water was used as the dispersion medium. The sample was added directly to the dispersion unit filled with deionized water. Before measurement, the sample was exposed to internal ultrasound (35 W), which was also active during the measurement. The stirring speed was 1200 rpm. The analysis was performed according to the Mie method using the refractive index RI determined by the device as 1.50-0.01 i.

[0101] Table 1 : Application of the silicone system, results

[0102] Table 2: Results

Claims

Patent claims Release coating for equipping a release liner, containing • a release agent and • 0.01 wt.% to 30 wt.%, based on the total weight of the release coating, of three-dimensional bodies K, characterized in that the bodies K contain at least 90 wt.% of one or more polysaccharides. Release coating according to claim 1, characterized in that the bodies K are ellipsoids. Release coating according to claim 1 or 2, characterized in that the bodies K have a D50 value of the volumetric particle size distribution, determined by means of laser diffraction as described herein, of at most 15 pm. Release coating according to one of the preceding claims, characterized in that - the bodies K are rotational ellipsoids and the bodies K have a D50 value of the volumetric particle size distribution of at most 12 pm. Release coating according to one of the preceding claims, characterized in that the release coating contains bodies K in a total of 0.1 to 10 wt. %, based on the total weight of the release coating. Release coating according to one of the preceding claims, characterized in that the bodies K are solid bodies. Release coating according to one of the preceding claims, characterized in that the bodies K contain at least 90 wt. % cellulose and / or starch. Release coating according to one of the preceding claims, characterized in that the release agent is selected from the group consisting of Silicones, fluorinated silicones, silicone copolymers, waxes, carbamates, and mixtures of two or more of the above-mentioned materials. Use of a release coating according to any one of the preceding claims as at least one outer layer on a release liner or as a backing coating of an adhesive tape carrier. Use according to claim 9, characterized in that the release coating has a layer thickness of 0.1 to 5.0 μm. Release liner comprising a carrier film and a release coating according to any one of claims 1 to 8. Use of a release liner according to claim 11 as a release liner in an adhesive tape used for bonding paper or film webs.

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