Release coating having a low coefficient of friction

Abstract

The present invention relates to a release coating for providing a release liner, · a release agent, and · contains a three-dimensional body K in an amount of 0.01% to 30% by mass based on the total mass of the release coating, characterized in that the body K contains at least one polysaccharide in a proportion of at least 90% by mass in total. The present invention also relates to the use of such a release coating on the back surface of a release liner or an adhesive tape, and their use in a release liner and an adhesive tape provided with the same.

Description

Technical Field

[0001] The present invention relates to the technical field of release coatings used as non-adhesive coatings for the back surface of release liners or adhesive tapes. More specifically, the present invention proposes a release coating having a low coefficient of friction.

Background Art

[0002] An adhesive tape (adhesive tape) coated with an adhesive (adhesive) on one or both sides is usually wound in a roll in an Archimedean spiral at the end of the manufacturing process. In the case of a double-sided adhesive tape, a pressure-sensitive adhesive is prevented from contacting each other, and in the case of a single-sided adhesive tape, the adhesive is covered with a covering material (also called a release material) before the adhesive tape is wound to facilitate rewinding. Such a covering material is known to those skilled in the art by the name of "release liner" or "liner". The liner is used not only to cover single-sided and double-sided adhesive tapes, but also to cover labels.

[0003] In addition, these release liners have the role of protecting the adhesive from being soiled before sticking. Furthermore, the release liner can be adjusted according to the type and composition of the release material, and the adhesive tape can be peeled off with a desired force (light force or heavy force). In the case of an adhesive tape coated with an adhesive on both sides, the release liner takes into account that the correct side of the adhesive is first exposed.

[0004] The liner or release liner is only an auxiliary material for the manufacture, storage, and further processing by die-cutting (Stanzen) of adhesive tapes and labels, not a part thereof. Furthermore, unlike the carrier (support) of the adhesive tape, the liner is not firmly adhered to the adhesive layer.

[0005] Commercially used release liners generally use paper or film carriers as release liners, and these liners are provided with an adhesive coating material (also known as an adhesive remover or anti-adhesive material) to reduce the tendency (release function) of adhesive products to adhere to these surfaces. A variety of substances can be used as such compounds, and these are also known as release materials: waxes, fluorinated or partially fluorinated compounds, especially various copolymers containing silicone or silicone. In recent years, silicone has been widely accepted as a release material in the field of adhesive tape applications due to its good processability, low cost, and wide range of property profiles.

[0006] A series of adhesive tapes coated with adhesive on both sides are unwound and pasted over the second adhesive with the release liner contained in the product. In manual pasting, the adhesive of the adhesive tape is brought into contact with the substrate by manually brushing it over the release liner. In this operation performed under pressure, a strong contact occurs between the release liner of the adhesive tape and the hand. Due to the release material used, the mainly used release liner has a dull surface with a high coefficient of friction. In this case, when used frequently and / or at high speed, it is unpleasant to apply the product and even painful.

[0007] It is known that the coefficient of friction of silicone release coatings can be reduced by various methods, but all have certain drawbacks.

[0008] Unmodified silicone-based systems, such as those formed by cross-linking functionalized siloxanes, have very good release properties but a high coefficient of friction. Using a silicone condensation system instead of the silicone addition system mainly used in the industry will slightly lower the coefficient of friction. However, the condensation system uses only a few toxic tin catalysts.

[0009] Those skilled in the art recognize that friction can be reduced by thinning the layer thickness of the release system (release system). However, at the same time, this often results in an undesirable deterioration of the release characteristics. Therefore, the thickness of the release coating cannot be freely thinned. In principle, the release coating must reliably cover at least the entire surface of the substrate. For example, in the case of a paper substrate with many openings, this means that a relatively thick release coating is required only to cover the entire surface.

[0010] The coefficient of friction of the release system can also be reduced by adding oils or substances that expand the structure formed when the release system is crosslinked. However, this leads to an increase in the proportion of migratory substances in the release system. These can adhere to the adhesive in contact with the release system and may reduce the adhesive strength.

[0011] EP0903385B1 describes reducing friction in a radiation-curable silicone system by adding spherical silicone particles produced by the controlled hydrolysis of methyltrimethoxysilane. Due to the complex and inflexible manufacturing process, the use of porous or hollow additives, which is particularly advantageous in one embodiment, is precluded.

[0012] US7198854B discloses a silicone formulation for treating fiber 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 results in an undesirable increase in the release force in the adhesive tape area.

[0013] US5620775A describes a molded article coated with a coating containing glass spheres with a diameter of 20 to 180 μm to improve reflectivity and friction and create a hydrophilic surface. Spheres with a diameter of 20 μm are clearly too large for use in release films or release papers, and the formation of a hydrophilic surface leads to a significant deterioration in the release behavior of the adhesive.

[0014] EP2535389A1 relates to a release coating composition, in particular a composition for providing a release coating layer on a release liner, said composition comprising: - a release agent - a powdery additive in the form of a three-dimensional body based on a polymer produced from vinyl constituent blocks, in an amount of 0.01% to 30% by mass (based on the total composition). The release coating has a low coefficient of friction, but the added polymer particles are being increasingly critically viewed in relation to the introduction of "microplastics" into the environment.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0016] One of the problems of the present invention was to provide a release layer having both a low coefficient of friction and a stable low release value.

[0017] A further problem of the present invention was to provide a release layer that, when used in an adhesive tape, shows only very slightly, ideally not at all, a decrease in adhesive strength due to the migration of some components of the release coating into the adhesive after contact.

[0018] A further problem of the present invention was to design the release layer to be toxicologically harmless and to meet the sustainability requirements, particularly those related to microplastics, as much as possible. Furthermore, the release layer needs to be easy to handle in terms of process technology.

Means for Solving the Problems

[0019] A first general subject of the present invention for solving these problems is a release coating for being provided on a release liner, the coating comprising · a release agent, and · based on the total mass of the release coating, containing 0.01% by mass to 30% by mass of a three-dimensional body K (three-dimensional body K), characterized in that the body K (solid K) contains at least 90% by mass in total of one or more polysaccharides.

[0020] According to a first advantageous embodiment of the present invention, the release coating consists only of a release agent and a three-dimensional body K.

[0021] The "three-dimensional body" is understood to be a three-dimensional and finite geometric shape that can be described by a boundary surface. A geometric shape is called three-dimensional when it is not completely contained in a plane, and is limited when a sphere that completely contains this shape is given.

[0022] The best-known bodies (Koerper) have flat, or group-like or individual spherical boundary surfaces. Examples include cylinders, cones, spheres, prisms, pyramids, tetrahedrons, cubes, and the five regular polyhedra. When a body is defined only by flat surfaces, it is called a polytope or a bounded polyhedron (polyhedron).

[0023] Thus, the bodies used according to the present invention have, among other things, the following shapes. · A parallelepiped, special examples being a cuboid and a regular hexahedron (cube) · A prism, generalized to a cylinder and special examples being a cuboid and a regular hexahedron · A pyramid, generalized to a cone and a special example being a regular tetrahedron · An antiprism, a special example being a regular octahedron

[0024] In particular, the body K having the above-described shape like a cube preferably has no corners or sharp edges. For this purpose, the actually existing corners and edges can be rounded or rounded. Preferably, the body K is an ellipsoid, particularly preferably a rotational ellipsoid, and particularly a sphere.

[0025] According to the present invention, the body K preferably has a D50 value of the volume particle size distribution determined by the laser diffraction method described herein of at most 15 μm, particularly preferably at most 13 μm, and particularly preferably at most 12 μm. The D90 value of the volume particle size distribution of the body K determined by laser diffraction described herein is preferably at most 30 μm, particularly preferably at most 27 μm, and particularly at most 25 μm. The diameter of the body K is understood to be a straight line connecting two points on the surface of the body and passing through the center of the body.

[0026] Particularly preferred is - the body K is a rotational ellipsoid, - the body K has a D50 value of the volume particle size distribution of at most 12 μm.

[0027] More preferably, the length of the minimum diameter of the body K deviates from the length of the maximum diameter by at most 20%, particularly preferably at most 10%. The "diameter of the body K" is understood to be a straight line connecting two points on the surface of the main body and passing through the center of the main body. As already described, the body K is preferably a sphere. In an ideal sphere, the lengths of the maximum diameter and the minimum diameter are the same. Even if it deviates slightly from the ideal spherical shape, it does not prevent it from being classified as a "sphere".

[0028] The body K may basically be any of a solid body (solid body), a hollow body, and a porous body, but a solid body is preferred.

[0029] According to the present invention, the body K contains at least 90% by mass in total of one or more polysaccharides. Preferably, the body K contains one or more polysaccharides in a total amount of at least 92% by mass, more preferably at least 95% by mass in total, particularly preferably at least 98% by mass in total. Most preferably, the body K consists of one or more polysaccharides.

[0030] The one or more polysaccharides are preferably selected from cellulose and starch. Preferably, the body K contains in total at least 90% by mass of one or more polysaccharides selected from cellulose and starch. More preferably, the body K contains in total at least 92% by mass, particularly preferably at least 95% by mass in total, particularly preferably at least 98% by mass in total of one or more polysaccharides selected from cellulose and starch. Most preferably, the body K consists of one or more polysaccharides selected from cellulose and starch.

[0031] The body K based on cellulose and / or starch is particularly characterized by the fact that it can be easily manufactured with the required particle size and has high resistance in silicone systems often used as a base for release coatings. For example, they have been proven to be very resistant to temperatures up to 170°C, which are commonly seen during crosslinking of silicone systems.

[0032] The starch-containing or starch-based body K is preferably based on potato, corn or rice starch.

[0033] The cellulose-containing or cellulose-based body K preferably consists of so-called microcrystalline cellulose.

[0034] In a preferred embodiment of the present invention, the body K is a sphere of cellulose or starch with a D50 value of the volume particle size distribution of at most 12 μm.

[0035] A major drawback of various conventional plastic-based release liner additives is that some of the particles are partially released from the release liner system during release liner application, unless they are fixed in the release liner, for example, by crosslinking. This can lead to the release of "microplastics". Although the three-dimensional body K of the present invention can also be peeled off from the release liner system, in this case, since the particles are toxicologically harmless and biodegradable, it is particularly preferable in terms of sustainability compared to conventional additives.

[0036] The body K is preferably incorporated into the release coating composition using a device selected from the group consisting of a blade stirrer, a dispersion disk, and an in-line disperser; particularly preferably, it is carried out using a dispersion disk or an in-line disperser. When using these two devices, undesirable aggregation of the body K can be particularly well eliminated.

[0037] In principle, all systems known to those skilled in the art can be used as release agents. Preferably, the release agent is selected from the group consisting of silicone, fluorinated silicone, silicone copolymer, wax, carbamate, and mixtures of two or more of the listed materials.

[0038] The release agent can include a solvent-based and / or solvent-free system, and a solvent-free system is preferred.

[0039] The release agent can be any of radiation-crosslinkable (UV- or electron beam-), condensation-crosslinkable, and addition-crosslinkable, and preferably is addition-crosslinkable.

[0040] The release agent is particularly preferably a crosslinkable silicone. Therefore, in the uncrosslinked state, it preferably contains a mixture of one or more crosslinkable catalysts and one or more so-called thermosetting, condensation-crosslinkable, or addition-crosslinkable polysiloxanes. In condensation-curing silicone systems, tin compounds such as dibutyltin diacetate are often included in the composition as a curing catalyst.

[0041] Silicone-based release agents with additional crosslinkability can be cured by hydrosilylation. These release agents typically contain the following components: · Alkenylated polydiorganosiloxane (especially a linear polymer having alkenyl groups at the ends) · Polydiorganohydrogensiloxane - crosslinking agent, and As a catalyst (hydrosilylation catalyst) for addition-crosslinkable silicone systems, for example, platinum or platinum compounds such as Karstedt catalyst (Pt(0) complex compound) are widely recognized.

[0042] Furthermore, photoactive catalysts, so-called photoinitiators, can also be used in combination with epoxy and / or vinyl ether-based UV-curable cationic crosslinkable siloxanes, or UV-curable radical crosslinkable siloxanes such as acrylate-modified siloxanes. Similarly, electron beam curable silicone acrylates can also be used. Appropriate systems can also include additional additives such as stabilizers or fluidity improvers (leveling aids) depending on the application.

[0043] Photopolymerizable organopolysiloxane compositions can also be used. For example, compositions crosslinked in the presence of a photosensitizer by the reaction between organopolysiloxanes substituted with (meth)acrylate groups and having hydrocarbon radicals directly bonded to silicon atoms (see EP0168713B1 or DE3820294C1). Also, compositions in which a crosslinking reaction occurs between an organopolysiloxane having a silicon-bonded hydrocarbon radical substituted with a mercapto group and an organopolysiloxane having a vinyl group directly bonded to a silicon atom in the presence of a photosensitizer can be used. Such compositions are described, for example, in US4725630A1.

[0044] For example, when using the organopolysiloxane composition described in DE3316166C1 having a silicon-bonded hydrocarbon residue substituted with an epoxy group, the crosslinking reaction is induced by releasing a catalytic acid obtained by photolysis of an onium salt catalyst. Other organopolysiloxane compounds that can be cured by a cationic mechanism include, for example, materials having propenyl-oxysiloxane end groups.

[0045] According to a particularly advantageous embodiment of the invention, the release coating has the following completely homogenized composition: · An addition-crosslinkable silicone system based on 92.5 to 99.5% by weight of vinyl-functionalized polysiloxane, methylhydrogen siloxane and a platinum catalyst; and · 0.5 to 7.5% by weight of ellipsoids of revolution, in particular spheres, composed of cellulose and / or starch, the length of the major diameter of which differs by a maximum of 10% from the length of the minor diameter.

[0046] A further subject of the invention is the use of the release coating according to the invention as at least one outer layer of a release liner or as a back coating of an adhesive tape carrier. The terms "outer layer" and "back coating" mean that one side of the relevant layer is exposed, in particular this side is directed outwards, i.e. away from the release liner or the other components of the adhesive tape, and is intended to come into direct contact with the (pressure-sensitive) adhesive composition. For this purpose, the release coating according to the invention can be applied to the carrier material, preferably as a closed layer. Preferably, the release liner is provided with the release coating according to the invention on both sides within the scope of use according to the invention.

[0047] When the release coating is silicone-based, a silicone-based system based on the release coating according to the invention can be applied from a solvent-free or solution to a carrier to produce a release liner or an adhesive tape with a release treatment on the back surface, and thereby, in principle, all coating processes known to those skilled in the art can be used. Subsequently, the silicone-based system can be dried if necessary.

[0048] Preferably, the release coating according to the invention has a layer thickness of 0.1 to 5.0 μm, more preferably 0.2 to 2.5 μm, particularly 0.4 to 2.0 μm.

[0049] In particular, paper or film can be used as the carrier material of the release liner. Preferred films used include biaxially oriented polyethylene terephthalate, polybutene, polypropylene, polyethylene, uniaxially oriented polypropylene, biaxially oriented polypropylene or polyethylene, particularly preferably polyolefin films, particularly polypropylene or polyethylene films, or polyester films.

[0050] As described above, a further subject of the present invention is a release liner comprising a carrier film and the release coating according to the invention.

[0051] A further object of the present invention is an adhesive tape with an adhesive treatment on one side, comprising a carrier material having a first surface and a second surface, a pressure-sensitive adhesive composition on the first surface of the carrier material, and a release coating according to the invention on the second surface of the carrier material.

[0052] The present invention also relates to the use of a release coating according to the present invention, preferably a silicone-based release coating, as at least one outer layer of a release liner covering one or both sides of a single-sided adhesive tape or a double-sided adhesive tape. Typically, a single-sided adhesive tape is usually covered on its adhesive side with a release liner. In the case of a double-sided adhesive tape, one release liner may be sufficient, but it is also possible to provide one release liner on each of the two sides of the adhesive.

[0053] As the adhesive according to the present invention, a pressure-sensitive adhesive is usually preferred and is present in the adhesive tape. A pressure-sensitive adhesive is an adhesive that enables permanent adhesion to an adhesive base even under relatively low pressure. A pressure-sensitive adhesive is permanently tacky at room temperature, that is, it has a sufficiently low viscosity and a high tack to wet the surface of each adhesive base even at low pressure. The adhesiveness of a pressure-sensitive adhesive is based on its adhesive properties, or the less prominent peelability is based on its cohesive properties. Various compounds can be used as the base of the pressure-sensitive adhesive

[0054] Preferably, the polymer base of the pressure-sensitive adhesive composition is selected from the group consisting of poly(meth)acrylate; silicone; natural rubber; and synthetic rubber, in particular styrene block copolymers having elastomeric blocks of unsaturated or hydrogenated polydiene blocks, such as polybutadiene, polyisoprene, copolymers of both, and other elastomeric blocks well known to those skilled in the art. The pressure-sensitive adhesive can include a combination of a plurality of base polymers and, in addition to the base polymer(s), can include, for example, tackifying resins, plasticizers, fillers, pigments, ultraviolet absorbers, light stabilizers, antioxidants and / or crosslinking agents, and other additives as required.

[0055] In the case of a carrier, or so-called transfer adhesive tape, the liner of the adhesive tape can be coated on one side with a pressure-sensitive adhesive in the form of a solution, dispersion, 100% (for example, from a melt) or by coextrusion. Alternatively, coating is also possible by transferring a pressure-sensitive adhesive layer by lamination. The adhesive layer can be crosslinked using heat or high-energy radiation.

[0056] The coating mass of the pressure-sensitive adhesive layer is preferably 10~120 g / m 2 , more preferably 25~100 g / m 2 and this means the weight after the necessary removal of water or solvent. A person skilled in the art will recognize that the numerical value of the coating mass approximately corresponds to the layer thickness in μm units.

[0057] To improve the adhesion, it is advantageous to physically pretreat the carrier side coated with the pressure-sensitive adhesive, for example, by flame, plasma or corona treatment. Alternatively or additionally, a primer layer, especially a solvent-free primer layer, can be applied, for example, by coextrusion, so that a primer layer is located between the carrier layer and the pressure-sensitive adhesive layer before the pressure-sensitive adhesive layer is applied to the carrier.

[0058] As the primer, known dispersion-based systems and solvent-based systems, for example, those based on isoprene or butadiene-containing rubbers and / or cyclo rubbers, can be used. Isocyanates or epoxy resins as additives improve the adhesion and, in some cases, also increase the shear strength of the pressure-sensitive adhesive.

[0059] Another subject of the present invention is the use of the release liner according to the present invention for an adhesive tape used for joining paper or film webs.

[0060] Flat web-like materials, especially paper, are often wound into reels on an industrial scale and then supplied to, for example, paper processing machines, printing machines, and packaging machines. During the continuous operation of such a system, it is necessary to attach a new starting reel in place at the end of the first reel of the flat web-like material and splice it in an appropriate manner without stopping the high-speed machine during the roll change. This process is called splicing.

[0061] In the paper industry, double-sided adhesive tapes are used for this purpose. Double-sided adhesive tapes basically consist of a carrier layer and two layers of pressure-sensitive adhesives, creating a connection between the end of the old material web and the starting portion of the new material web. The end of the old material web and the starting portion of the new material web are adhered.

[0062] For the purposes of the present invention, the general term "adhesive tape" includes all flat structures such as two-dimensionally extended webs or web portions, tapes with extended length and limited width, tape portions, labels, die cuts, etc.

[0063] The release coating according to the present invention enables the provision of a release liner or the back surface of the adhesive tape coated with a release coating having a significantly lower coefficient of friction compared to the same system in the absence of the body K according to the present invention. These additives effectively reduce the friction of the release coating while maintaining good release properties for various adhesives.

[0064] Furthermore, the body K present in the release coating according to the present invention has also been shown to reduce the drop in the adhesive strength (tack, adhesiveness) of the pressure-sensitive adhesive covered by the release system in a solvent-based silicone release system on a film carrier. It has been observed that at least in the range of 1 to 8% by mass of the proportion of the body K, a significant decrease in the drop in adhesive strength is observed as the proportion increases. Therefore, a further subject of the present invention is a release liner comprising a carrier film and a solvent-based release coating, wherein the release coating contains, in each case based on the total weight of the release coating, 1 to 8% by mass, more preferably 2 to 6% by mass of the three-dimensional body K, and the body K contains at least 90% by mass of one or more polysaccharides. All embodiments of the release coating or release liner according to the present invention described herein are considered to be preferable for the release liner as long as they are applicable to the release liner described in this paragraph. In particular, the material of the carrier film of the release liner described herein is selected from the group consisting of biaxially stretched polyethylene terephthalate; polybutene; polypropylene, particularly uniaxially stretched polypropylene and biaxially stretched polypropylene; and polyethylene. The material of the carrier film is particularly preferably uniaxially stretched polypropylene (MOPP).

[0065] The "solvent-based release coating" or "solvent-based silicone release system" means that although the release system is actually applied as a solvent-containing system, after crosslinking that is usually thermally initiated, at most a trace amount of solvent remains in the release system. Nevertheless, those skilled in the art refer to it as a "solvent-based system" or "solvent-containing system" and characterize the special properties of such solvent-based release coatings.

Examples

[0066] Example Unless otherwise specified, all ratios of components are described below by mass ratio.

[0067] Manufacture and Coating of Release System The KSC950 white paper (manufactured by UPM) with a width of 1300 mm was coated with the release system formulations shown below, with or without additives, using a laboratory coating device to produce release liners. The additives were stirred into the formulations using a paddle mixer. After coating, the release system was cured in a convection oven at 160 °C for 30 seconds.

[0068] Regarding the liners manufactured in this way, investigations were carried out regarding the coefficient of friction, the peel force (Trennwert) of test tapes tesa® 7475 and test tape tesa® 50110, as well as the coating amount and the reduction amount of adhesive strength. Test tape tesa® 7475 is a 40-μm-thick PVC carrier coated with a resin-modified acrylate pressure-sensitive adhesive at 95 g / m 2 . Test tape tesa® 50110 has a thickness of 300 μm and uses a natural rubber pressure-sensitive adhesive on a cloth carrier.

[0069] Measurement of Release Characteristics Test tapes tesa® 7475 and tesa® 50110 with a width of 20 mm and a length of 300 mm were each pasted onto the release liners. For each sample, three liners with test tape tesa® 7475 and three liners with test tape tesa® 50110 were stored under pressure and temperature for 24 hours. During storage, the temperature was 40 °C for test tape tesa® 50110 and 70 °C for test tape tesa® 7475. The pressure was 4 N / cm 2 in both cases.

[0070] After that, the samples were stored in a climate-controlled measurement chamber at 23 °C and a relative humidity of 50% for 2 hours, and then the peel force was measured using a Zwick tensile testing machine. The peeling speed was 300 mm / min and the peeling angle was 180°. The average value of the measured values of the three laminates was reported as the result.

[0071] Measurement of Adhesion Reduction Furthermore, the possibility of migration of silicone and various additives was evaluated by measuring the decrease in the adhesive strength of test tape tesa® 7475. For this purpose, the adhesive strength of the new transfer 7475 was measured on a steel surface by a tensile test (Zwick tensile testing machine, 300 mm / min, 180°).

[0072] Subsequently, in order to measure the peeling behavior, the test tape tesa® 7475, which had been pre-stored for 24 hours at pressure and temperature together with the liner, was similarly pasted onto the steel material, and its adhesive strength was measured by a tensile test. The amount of decrease in adhesive strength was calculated by the following formula.

[0073] [Number]

[0074] Measurement of Silicon Coating Amount The coating amount of the release system was measured by X-ray fluorescence analysis. For this purpose, the carrier coated with the release system to be investigated was analyzed by an X-ray fluorescence analyzer Lab-X 3000 (Oxford Instruments) using an internal standard (polydimethylsiloxane). After excitation with X-rays, the emitted energy is recorded in the form of Si-specific fluorescence radiation and converted by the apparatus stoichiometrically to the coating amount of the silicone release system in g / m 2 units. False detection due to additives in the carrier material is taken into account by determining a zero value.

[0075] Measurement of Coating Characteristics To answer the question of whether a pleasant skin feel can be obtained when the release system is coated, samples coated with the release system were evaluated by direct comparison by five subjects. The evaluation criterion was the skin feel when the liner coated with the release system was pasted by applying strong pressure by hand, i.e., the usual method known to those skilled in the art in the application of pressure-sensitive adhesives. The evaluation was carried out as follows. - 1 = Comfortable - 2 = Uncomfortable

[0076] Silicone-based Silicone-based A is an addition-curing silicone-based product from Wacker. 9.75 g of DEH 915 (polydimethylsiloxane functionalized with vinyl groups) was mixed with 0.33 g of V24 (methylhydrogenpolysiloxane) and 0.08 g of Kat OL (platinum catalyst, also known as "Karstedt catalyst").

[0077] To the silicone-based product applied to the outer side of the liner, 2.5% by mass of PMMA spheres (Sepimat spheres SB, SEPPIC, solid beads with a particle size of 1 - 5 μm) or starch spheres (Sepifine® BB, SEPPIC, solid beads, D50 value of the particle size distribution 11 μm) was added, and no further additives were added to the system applied to the inner side of the liner. The mixture was homogenized, applied to the carrier, and then crosslinked as described above.

[0078] Measurement of Particle Size Distribution The particle size distribution was measured by the laser diffraction method using a "Bettersizer S3 Plus" device. Deionized water was used as the dispersion medium. The sample was directly added to the dispersion unit filled with deionized water. Before measurement, the sample was exposed to internal ultrasonic waves (35 W), and this ultrasonic wave remained effective during the measurement. The stirring speed was 1200 rpm. The device measured the refractive index RI 1.50 - 0.01i and evaluated according to Mie.

[0079] [Table 1]

[0080] [Table 2]

Claims

1. A release coating for providing a release liner, comprising: - a release agent, and - based on the total mass of the release coating, 0.01% to 30% by mass of a three-dimensional body K, wherein the body K contains at least 90% by mass in total of one or more polysaccharides, characterized in that the release coating.

2. The release coating according to claim 1, wherein the body K is an ellipsoid.

3. The release coating according to claim 1 or 2, wherein the body K has a volume particle size distribution D50 value of at most 15 μm, determined by laser diffraction as described herein.

4. - the body K is a prolate ellipsoid, and - the body K has a volume particle size distribution D50 value of at most 12 μm, characterized in that the release coating according to any one of claims 1 to 3.

5. The release coating according to any one of claims 1 to 4, characterized in that the release coating contains the body K in a proportion of 0.1 to 10% by mass in total based on the total mass of the release coating.

6. The release coating according to any one of claims 1 to 5, characterized in that the body K is a solid body.

7. The release coating according to any one of claims 1 to 6, characterized in that the body K contains cellulose and / or starch in a proportion of at least 90% by mass.

8. The release coating according to any one of claims 1 to 7, characterized in that the release agent is selected from the group consisting of silicone, fluorinated silicone, silicone-copolymer, wax, carbamate, and mixtures of two or more of the above materials.

9. Use of the release coating according to any one of claims 1 to 8 as at least the outer layer of the release liner or as the back coating of the adhesive tape carrier.

10. The use according to claim 9, characterized in that the release coating has a layer thickness of 0.1 to 5.0 μm.

11. A release liner comprising a carrier film and the release coating according to any one of claims 1 to 8.

12. Use of the release liner according to claim 11 as a release liner in an adhesive tape used for joining a paper web or a film web.

Images