MXPA06007459A - Process of microstructuring of a surface of a multi-layered flexible substrate, and microstructured substrate - Google Patents

Abstract

A method of forming a three-dimensional microstructure on a flat surface of a support, comprising the application of a first flat and uniform layer (2) of silicone on said surface of support (1) and the application on the first layer of silicone of a second three dimensionally microstructured layer (3) of silicone, said first layer and second layer of silicone become integrally connected to thus form a common three-dimensional microstructure ensuring anti-adhesive properties distributed regularly on the surface of the support, so that any flexible surface of substrate, in particular a surface of adhesive deposited on said layers of silicone will be microstructured by inverse replication of the three-dimensional microstructure formed by the two layers of silicone, where said layers of silicone are fixed by hardening by heating or by exposure to an ultraviolet or electronic radiation, or a combination thereof, applications thereof and films, notably self-adhesive films, such as those microstructured by said method.

Description

report: 23 February 2006 Previous Correction: Date of publication of the revised international search see PCT Gazette No. 08/2006 of 23 February 2006 report: 27 April 2006 For two-letter codes and other abbreviations, refer to the "Guid- (15 ) Information about Corrections: anceNotes on Codes and Abbreviations "appearing at the beginning PCT Gazette No. 17/2006 of 27 April 2006 ning qf each regular issue qf the PCT Gazette.

METHOD FOR FORMING A THREE-DIMENSIONAL MICROSTRUCTURE ON A SURFACE, USES OF THE SAME, AND MICROSTRUCTURED PRODUCTS SO OBTAINED DESCRIPTIVE MEMORY The present invention relates to a method for forming a three-dimensional microstructure on a flat surface of a support, to the uses of said method, as well as to the products and in particular to the self-adhesive films comprising said three-dimensional microstructured surface. It is known that to provide films made of adhesive with a sensitive pressure, whose topography is conferred through the contact of the three-dimensional microstructured surface of a protective montable coating as support, which is essentially the inverse form of the three-dimensional microstructure with which the The surface of the adhesive is brought into contact, and the methods a for the formation of said self-adhesive films. According to these methods, the three-dimensional structures are obtained either through the mechanical stamping of the support comprising a flat film made of silicone through the silicone coating on the support which already has a microstructured surface, in this case coinciding with the topography of the support. Although the methods for forming self-adhesive films are generally rather satisfactory, they are limited to the application, since this can only be produced on expensive polyethylene or polypropylene supports. In the case of polyethylene and silicone supports, the formation of the microstructures in the silicone is carried out through hot stamping at speeds in the order of 0.9 m / minute of the engraved cylinder which is used for this purpose. that considerably decreases productivity and gives rise to production costs and raises the production costs of the final products. Various articles and other pressure-sensitive micro-constructed adhesive materials or films are described through patent publications for example, EP 149135 which discloses pressure-sensitive adhesive structures having islands of adhesive, EP 189598 describes existence of removable labels that they have adhesive segments, and EP 861307 discloses an adhesive sheet having a plurality of adhesive pegs, and also patent application WO 97/43319 which relates to a reusable top layer film in the preparation of a device carrying stable polymeric laminate data, said top cover film comprises an upper cover layer which is formed of a composition comprising a polymerizable composition, and / or a polymeric binder, which is substantially free of plasticizer, and wherein the weight ratio of the polymerizable composition with the polymer binder Iberian is between 0.75: 1 and 1.50: 1 inclusive. U.S. Patent No. 4,986,496 refers to an article capable of reducing the drag of the fluid flow and comprising a thermofix polymer sheet formed in situ from the reaction product of an isocyanate with a polyol, said sheet having a surface in contact with said fluid comprising a series of parallel peaks separated from one another through a series of parallel valleys. The patent application EP 0 382 420 A2 provides a plastic article of composition comprising a flexible, resistant substrate, one face of which bears a microstructure of discontinuities, whose microstructure has a depth of 0.025 mm to about 0.5 mm, and comprising a crude oligomeric resin having hard segments and smooth segments, the cured resin is substantially confined to the microstructure portion of the composition. One of the purposes of the present invention, consequently, consists in overcoming the aforementioned drawbacks and providing a method for forming a three-dimensional microstructure on a flat surface of a supplementing support differs from the known methods consisting in deforming a previous flat surface, presilized or not to obtain the final microstructured surface desired. For this purpose, according to the present invention, the aforementioned method for making three-dimensional microstructures comprises the application of a first flat and uniform silicone layer on said support surface and the application on the first silicone layer of a second layer three-dimensionally microstructured silicone, said first layer and said second silicone layer are integrally connected so as to form a common three-dimensional microstructure, ensuring the anti-adhesive properties distributed regularly on the support surface, so that no flexible surface of the substrate, in particular a adhesive surface deposited on said silicone layers will be microstructured through the inverse replication of the three-dimensional microstructure formed through the two layers of silicone, said silicone layers are fixed through heat hardening or through exposure to a radi ultraviolet or electronic, or a combination of these. Another purpose of the present invention is to provide a method for three-dimensionally micro-constructing a surface made of a flexible substrate, in particular an adhesive surface, which can be produced on any type of substrate, such as papers, plastic films, or other , and that allows to work at a very high speed, in this way increasing the productivity considerably compared with the previous methods. For this purpose, according to the present invention, a three-dimensional microstructuring method mentioned above comprises the application of a first layer of Siicone, which is substantially flat and uniform on the surface of a support, - the application of the first layer of silicone of a second three-dimensionally microstructured silicone layer, wherein said first and second silicone layers are integrally connected in this way forming a three-dimensional microstructure that ensures that the properties Anti-adhesive are uniformly distributed over the surface of the support, and the deposition of the flexible surface of the substrate, in particular of the adhesive surface, in the aforementioned silicone layers in such form that said surface made of flexible substrate, in particular of adhesive, is Microconstruye through inverse replication of the common three-dimensional microstructure formed by the first silicone layer and the second silicone layer, wherein said silicone layers are fixed through heat hardening or through exposure to ultraviolet or electronic radiation or a combination of both. Advantageously, the first silicone layer comprises at least less a polyorganosiloxane functionalized with groups - Yes - H I as an entanglement agent, at least one functionalized polyorganosiloxane which can react with the entanglement agent, or comprises polyorganosiloxanes functionalized with groups l-Si-HI as the entanglement agent, and at least one polyorganosiloxane functionalized with St-RI groups that can react with the entanglement agent, wherein R comprises at least one ethylenic unsaturation, and optionally in one or the other In this case, an activation catalyst for the aforementioned entanglement reaction is hardened through heating or through exposure to ultraviolet or electronic radiation. According to an advantageous embodiment of the invention, the aforementioned second silicone layer comprises at least one polyorganosiloxane and, advantageously, a polydimethylsiloxane with an acrylate and / or epoxy function, and optionally an activation catalyst. According to another advantageous embodiment of the invention, the second silicone layer comprises a polydimethylsiloxane with an acrylate function and a ketone-type catalyst, advantageously of the benzophenone type, or comprises a polydimethylsiloxane with an epoxy function and a salt-type catalyst of iodonium, and that straightens through exposure to ultraviolet radiation. According to yet another advantageous embodiment, the second silicone layer does not comprise any activation catalyst and is hardened by exposure to electronic radiation. The invention also relates to dimensionally microstructured films, and self-adhesive films comprising a surface such as one that has been three-dimensionally microstructured, through the aforementioned method, notably comprising patterns that can be used for decorative, advertising or other purposes. purposes, notably on the surface opposite the adhesive surface of the anti-adhesive films. As already indicated above, to form a three-dimensional microstructure on the flat surface of a support, such as a flexible paper-type support or a plastic film, it is applied to a first layer of substantially flat and uniform silicone on said support surface and a second layer of silicon that has been three-dimensionally structured is applied on the first silicone layer, in such a way that these silicone layers are integrally connected to form a common three-dimensional microstructure ensuring the anti-adhesive properties of the surface on the support surface. In this way, any flexible substrate surface, in particular any adhesive surface, deposited in both integrally connected layers of silicones will be microconstructed through inverse replication of the three dimensional microstructure formed by the above. According to a particularly preferred embodiment of the invention, to impart a three-dimensional microstructure to a flexible substrate surface, and in particular to an adhesive surface, a first layer of continuous silicone is applied which is substantially flat and biforne on the supporting surface, such as one made of paper, which, for example, can be passed through a calender or dimensioned, or a plastic film, such as one made of polyethylene, polyester, polypropylene, polyvinyl chloride, polyamide, or a material similar, and a second layer of silicone that has been three-dimensionally structured is applied to the first silicone layer, in such a way as described above that these silicone layers are integrally connected to form a three-dimensional microstructure ensuring the anti-adhesive properties that are distributed uniformly on the surface of the support. Then, it is deposited by means well known in the art, for example, by coating and / or lamination of the flexible surface of the substrate or, in particular, the aforementioned adhesive surface, on the silicone layers in such form that said substrate surface, in particular adhesive, is microconstructed through inverse replication of the common three-dimensional microstructure formed by the first and second silicone layers. In this regard, the term "microstructured through reverse replication" refers to the fact that the topography obtained on the surface of the flexible substrate, in particular of the adhesive, is the inverse motive of the surface topography formed by the combination of the first and second silicone layer, whose three dimensions in space are substantially similar or similar to the previous ones. Throughout the present description, as well as in the claims, the term "substrate" denotes any product that can be microconstructed through inverse replication of the microstructure formed by the combination of the first layer of silicone and the second layer of silicone and the term "support" will denote any product to which the first silicone layer or the silicone layer is applied which is substantially flat and uniform. The first substantially flat and uniform layer of silicone is formed of silicone composition which is based on one or more functionalized polyorganosiloxanes (POS) with groups g as the entanglement agent, and one or more functionalized polyorganosiloxanes (base resin) which can react as the entanglement agent through polycondensation in the presence of a solvent, and preferably a tin-based activation catalyst, except in the case of the hardening of the layer through exposure to electronic radiation. In a variant, one base resin or one or more polyorganosiloxanes operated with groups could be used s - n which can react with the crosslinking agent through polyaddition with or without the solvent, wherein R comprises at least one ethylenic unsaturation, preferably a vinyl unsaturation, in the presence of a platinum and / or radium catalyst.

This silicone composition furthermore comprises additives such as those conventionally used in this type of application, mainly an adhesion modulator, for example, based on a silicone resin comprising siloxyl units, reaction accelerators and inhibitors, pigments, agents surfactants, fillers or similar substances. To facilitate the application of the silicone layer, the silicone composition mentioned above can be liquid and diluted in a solvent such as hexane or toluene and, for reasons pertaining to hygiene and safety, it can be in the form of a dispersion / emulsion watery The expression "flat and uniform" denotes the fact that the silicone layer does not comprise any roughness of surface or roughness that could detract from the flat configuration of its surface, that is, the silicone layer will tend to harden and be continuous on a surface of support without having any rupture that could interfere with the released characteristics finally desired or the three-dimensional topography of siliconized support after the application of the second layer. This silicone composition constituting the first layer, which is made either of a solvent base or without a solvent, is hardened through entanglement with heat in a polyaddition reaction to polycondensation, for example, it is subjected to temperatures of 70. -220 ° C, advantageously 100-180 ° C, or under exposure of radiation energy, such as electronic ultraviolet radiation. In the case of a thermal treatment, the silicone layer can be hardened by passing the support to which it is applied through thermal ovens whose temperature can vary from 100-220 ° C, with a residence time in the thermal oven that can be on the scale of 2 seconds to '1 minute. The coating speed is usually determined through the temperature profile in the ovens and through the length of the ovens. In the case of a treatment under radiation energy, the silicone layer is melted in a UV furnace or a furnace with electronic radiation and hardens almost instantaneously; however, the silicone composition of the radical or cationic type does not require the presence of a catalyst during exposure to electronic radiation. The flat layer of silicone can have a thickness of 0.4-1.6 μm, advantageously 0.7-1.2 μm. This silicone layer, in general, is applied with a 5-roll system for solvent-free compositions with a coating roller type system and Dr. Mayer's bar for solvent or aqueous base compositions. The fatty or the thinness of the first capable silicone can be used if desired. However, thicker layers have a higher material cost and thinner layers may require taking into account the formation of undesirable ruptures in the covering on the support. It will be appreciated that the first layer of silicone. The same can be constructed through the application of multiple layers of silicone and that the formulation of each layer can vary, however, to facilitate the manufacture, a single layer can be applied. In accordance with the present invention, the second silicone layer or the three-dimensionally microstructured layer of silicone is formed of a silicone composition comprising one or more polyorganosiloxanes and, advantageously, one or more polydimethylsiloxanes with an acrylate and / or epoxy function, and optionally an activation catalyst as a function of need. This silicone composition is solvent-free and hardens either through exposure or ultraviolet radiation (polydimethylsiloxane with the function of acrylate and / or epoxy) or through exposure to electronic radiation (polydimethylsiloxane with the acrylate function), in whose case does not require the presence of an activation catalyst. A suitable UV dose to ensure correct interlacing of the silicone is generally greater than 700 mJ / cm2. When the silicone composition comprises one or more polydimethylsiloxanes with the acrylate function, and the microstructured layer of silicone is hardened by UV radiation (radical system), a ketone photoinitiator, advantageously of the benzophenone type, can be used as the catalyst. , a specific example is 2-hydroxy-2-methyl-1-phenylpropanone. To optimize the version of the microstructured layer for the first silicone layer, an adhesion agent may be incorporated such as an adhesion agent such as polydimethylsiloxane, dipropoxylated diglycidyl ether may be incorporated. In the case where the silicone composition comprises one or more polydimethylsiloxanes with an epoxy function, a photoinitiator of the iodonium type such as tetrakis (pentafluorophenyl) borate of diaryl iodonium or iodonium hexafluoroantimonate (cationic system) is used as the catalyst. In general, radical systems are preferred over cationic systems, because they have a better stability of anti-adhesive properties (release of the substrate) over time while, however, require the presence of a system to become inert without nitrogen during the entanglement reaction to decrease the oxygen level in the gas atmosphere to less than 50 ppm. As the first silicone layer, the silicone composition used to form the second microstructured layer may comprise other additives, such as fillers, accelerators, inhibitors, pigments, and surfactants. The microstructured silicone layer coating is generally carried out using an engraved cylinder. Suitable coating speeds of 10-600 m / minute can be used. The amount of silicone (polydimethylsiloxane) will vary depending on the function of the cylinder's engraving, the viscosity of the composition, the viscosity of the addition products that can modify the rheological behavior of the silicone layer, and as a function of the silicone temperature . In fact, the silicone is transferred from a roller that is etched onto the surface of a first layer of silicone to be coated. The engraving of the engraved cylinder is filled through immersion in an ink fountain or a receptacle containing silicone. Excess silicone is usually eliminated through a doctor's bar means. A rubber counter roller will be used to ensure proper transfer of the silicone layer. The engraving of the cylinder will determine the topography of the silicone layer, which is the desired three-dimensional microstructure. The amount of silicone deposited can be controlled and can vary, for example, from 3 to 25 g / cm2, advantageously from 4 to 15 g / cm2. The three-dimensional microstructure formed by the combination of the first layer and the second silicone layer advantageously consists of microstructured units, for example micro-planar, fluted, or grid-like patterns, whose peak height can be predetermined. Beneficially, peak heights of 30-50 μm, advantageously 5-25 μm, can be used. For example, the engraving used can have the following characteristics: shape: truncated pyramidal, depth (height): 50 μm, opening: 100 μm, diagonal measurement of the pyramid: 500 μm, theoretical volume: 15 cm3 / m2. The microstructured layer of silicone that is applied to the flat surface of the first layer of silicone should be interlaced as quickly as possible, for example, through UV radiation or electron beam, and in this way, in the case of UV treatment, the UV lamps are preferably placed as closely as possible to the silica gel station (where the second plate is applied to the first layer) .- The energy of the UV lamps can be in the range of 120 W / cm to 240 W / cm or more, and the coating speed of the microstructured silicone can be determined (approximately 100 m / min at 120 W / cm can be achieved). During coating of the microstructured silicone with the aid of a special etched cylinder (the so-called "reverse or negative" engraving) of the flat silicone layer, the latter can be deposited first on the support, for example, of paper or plastic or during a separate coating (presiliconization process), or together, i.e. the machine that is in the process of coating the microstructured layer of silicone. The coating of the microstructured silicone layer can also be carried out using a rotating molecular sieve, in which case the silicone is passed through the screen in contact with the surface to be coated of the first layer. For example, the sieve used can have the following characteristics: a 30 mesh screen; thickness of 200 μm, 15% open surface, hole dimension of 345 μm, theoretical volume of silicone fluid passing through: 30 cm3 / m2. These parameters are illustrative and may vary as desired. It is not recommended to interlace the microstructured layer through the thermal path, because the temperature required for interlacing could destroy its three-dimensional structure as a result of the flow even before it can be fixed through interlacing. In addition, another drawback from the point of view of the strength of the spatial structure of the motif during coating could be that the viscosity of a silicone composition that has been treated through the technical route could be in the order of 200. -400 mPa.s, while, if treated through radiation it could be higher than 1000 mPa.s. If a support is covered are silicone, such as paper, polyester, or other material, the surface tension of this support in general is always greater than the tension of the silicone surface. The immediate consequence is that the silicone moistens the surface of the support and thus spreads on it. Conversely, if a surface is covered with silicone having a surface tension that is less than that of the silicone, ie, for example, a surface that has been treated with fluoro, then a shrinkage of the silicone will be observed which can lead to the dehumidification The liquid silicone film is separated on the surface of the support to form a group of droplets that are separated from one another. Since it is absolutely necessary to avoid any deformation of the three-dimensional structure of the silicone when it has been deposited on the surface of the support, the surface of the support should ideally have the same surface tension and the silicon that is being deposited on it and thus ideally a surface of the same nature as silicone: a siliconized surface. In this case, the silicone with which it is coated will not theoretically tend to retract or spread. Normally, its structure in this way will remain stable (except for the effect of gravity of the faces of the three-dimensional structure that will depend on the great extent of the viscosity of the silicone with which it is being covered, the highest is the best) in the UV or electronic radiation station, where the structured layer of silicone will definitely be fixed through interlacing. The surface tensions of the silicone layers are 19-24 n / m (or dyne / cm), advantageously 21-23 mN / m. The method that is generally used to determine the surface tension is the Owens-Wendt drop method with three components (liquids used: hexadecane, water, glycerol, diiodomethane, measurement temperature: 23 ° C). It is noted that there is very little difference from the point of surface tension between the silicone compositions, if they are treated through the thermal path or through, radiation. A silicone layer that has been heat treated will substantially have the same surface tension as the silicone layer that has been treated with UV radiation. The microstructured silicone layer can consequently easily be applied to the flat surface of a silicone layer that has been thermally interlaced. According to the invention, the second silicone layer is deposited on the first silicone layer which has then become integrally connected in this way to form a common three-dimensional microstructure which ensures the anti-adhesive properties (release of the substrate) that they are uniformly distributed on the surface of the support, and on the siliconized support a liquid solution or paste is deposited which, after being dried through the thermal path, for example, in thermal ovens, or under exposure to UV ray radiation or electron, will form a flexible substrate or film whose surface topography is substantially the inverse topography of that of the three-dimensional microstructured silicone. Certainly, the silicone layers - they will fulfill a double role, the paper must impose a reverse topography on the surface of a film that will be in close contact with them and an anti-adhesive agent that will facilitate the separation of the film made from the material that was applied to the microstructured silicone. To make a flexible film, any plastic film may be appropriate, for example, molten polyvinyl chloride, or a film made from a solvent base, or in the form of an organosol or plastisol. Other cast films could also be considered, such as propylene, polyurethane, and polyethylene.

Certainly, the main objective of the method of the invention is to impart a surface finish to the molten film through micro-replication, for example, for the visual aspect or for the various technical reasons. According to a particularly advantageous embodiment of the invention, a flexible film such as a plastic film is used as a substrate, for example a polyvinyl chloride film, the surface of which is covered with an adhesive, in order to give the adhesive a microstructure which corresponds to the inverse image of the microstructured silicone. The adhesive layer, in that case, will advantageously be coated directly on the microstructured silicone, or pressed onto the silicone through lamination using a lamination device. During a direct coating, the adhesive will be in the liquid form, for example, in solution in organic solvent or a mixture of organic solvents or in an emulsion in water, or in the form of a solid, i.e. in the form of an adhesive without a solvent that melts hot on the microstructured silicone. Since the coating process used to coat the adhesive on the silicone must be such that it does not affect the microstructure of the silicone through abrasion, the above procedure is preferably carried out using a cutting extruder, a coating roller equipped with a doctor's scraper or bar. As a type of adhesive, any of the adhesives that are applicable in the field considered can be used. In this regard, mention is made of adhesives based on acrylic, silicone rubber, and polyurethane. These adhesives may be solvent-based, water-based, or solvent-free, in the withdrawal state. The selection of the adhesive will determine the ease of replication of the silicone microstructure by more or less permanent maintenance of its reverse microstructure when the substrate containing the microstructured adhesive is then applied to a given object, such as a deployment window, and a painted canvas or a panel. Particularly suitable are the self-adhesive resins which cross-link themselves when heated, and which are based on an acrylic copolymer dissolved in a mixture of organic solvents, the self-adhesive resins which can be entangled through the addition of isocyanate, and are based on an acrylic copolymer dissolved in a mixture of organic solvents, the acrylic copolymers in an aqueous dispersion, wherein the acrylic monomers for that purpose are preferably 2-ethylhexyl acrylate, butyl acrylate, and acrylic acid, and the adhesives based on natural and / or synthetic rubber, which may or may not be dissolved in a mixture of organic solvents. These adhesives may contain one or more additives, such as resins that ensure bonding, antioxidants, plasticizers, fillers, pigments or similar substances. To clarify the invention, Figure 1 in the drawings of the appendix represents a slightly elongated cross-sectional view of a support 1 to which the first layer of silicone 2 and the second layer of silicon 3 microstructured, respectively, have been applied. As you can see the first and second layer 2 and 3 and support 1 adhere together to form a three dimensional microstructure unitary This microstructure 4 comprises a plurality of ridges or grooves consisting of the microstructured layer 3 and fixed to the support 1 through the first layer 2. Together with the first layer of silicone 2 and the second layer of silicone 3 a siliconized surface is formed continuous 5 on the support 1. The siliconized surface 5 has anti-adhesive properties extending from the lower regions 5a continuously over the ridge areas 5b to provide a surface adapted to release a substrate in contact therebetween. The plurality of ridges or grooves are preferably evenly distributed over the siliconized surface 2a of the support 1, and facilitates the separation of a substrate film (see Figure 7) with or without adhesive that will have been deposited on the microstructured silicone. The following tests and examples better illustrate the invention although in no case limit it.

Tests on a pilot installation The materials used, the conditions of operation and the results of the tests are given in the following Tables and Table 2. 1. Coating of a silicone "grid" on presilized paper The coating of the microstructured layer ("grid") of silicone is carried out through the "reverse" engraving, which is through pyramids on the cylinder board . These pyramids may have a truncated shape or they may be similar to a pyramid that has its apex removed in a cylindrical shape. The characteristics of the engraving (see Figure 2a: plan view of the engraving, and Figure 2b: transverse view along the line llb). Cylinder No. 58472 covered with chrome. Depth: 0.050 mm. Opening: 0.100 mm. Diagonal measurement of the pyramid: 0.500 mm. Bottom part: 0.015 mm. The filling of the engraving is carried out either by using a closed chamber equipped with doctor bars, and by immersing the engraving in a silicone bath, where the excess silicone on the surface of the engraving is then removed with a bar doctor (made of steel, nylon or any other material). The fixation of the microstructured layer of silicone is carried out using a battery of mercury UV lamps - with an average pressure and energy of 200 Wm.

TABLE 1 Siliconization (with an engraving roller and a closed chamber) fó * The Brookfield viscosity of the silicones was measured (axis 4, speed 20 rpm), unit of centipoise = 1 mOa.s. 1) Signback 13 is a paper measured with caolin of 130 g / cm2. 2) R630GE (SS) is a mixture of polyorganosiloxane with the Pt catalyst, without solvent. 3) UV902G (+ CRA 709) is a mixture of polyorganosiloxanes comprising acrylate functions, and was placed in the presence of 2-hydroxy-2-methyl-1-phenylpropanone as photoinitiator, from the company Goldschmidt. 4) UVPC 900 RP is a mixture of polyorganosiloxanes comprising acrylate functions, and was placed in the presence of 2-hydroxy-2-methyl-1-phenylpropanone, from the company Roída. 5) UV 902G is a mixture of functionalized polydimethylysiloxanes such as the acrylate function and 2-hydroxy-2-methyl-1-phenylpropanone from the company Goldschmidt. 2. Adhesive coating Formulation of the adhesive used: Acrylic copolymer in solution in a mixture of organic solvents: 17 kg. Butyl acetate (main solvent): 2.8 kg. Interlacing agent: 0.160 kg.

Drying temperature profile: 60 ° C, 80 ° C, 100 ° C, 120 ° C. Coating speed: 20 m / min. Weight in grams of the adhesive: 20-25 g / m2.

TABLE 2 Coating of the adhesive 1) M8129 is a sheet of glossy PVC paper that has a 90 μm grease. In this way it can be seen that the coating of a relief silicon through the so-called reverse engraving produces excellent results. Figures 3A-3B are the scanning of the electron micrograph of the microstructured silicone surface of Example 2 according to the invention (amplification X 15 and X 30). Figure 4 is the scanning of an electron micrograph of the microstructured surface of the silicone obtained by methods known from the prior art.

According to this known method, the silicone layer, deposited on the glossy surface of the polyethylene film of two-sided polyethylene paper, was micro-etched with heating (110 ° C) at a low speed (0.9 m / min) by a engraved cylinder; The counter cylinder is a silicone rubber roller that has a shore hardness of 85 and reheated to 120 ° C; The pressure exerted between the two cylinders is 22 N / mm2. As you can see, the microstructured support of the invention has a silicone surface (Figure 3A and 3B) with very regular characteristics that are rounded to the level of the ridges, which prevents or reduces the possibility of transferring the image of the silicone pattern to the surface of the substrate, for example, a flexible PVC film, which has no alteration in the appearance of the surface of the substrate film. This is not the case with the micro-combs of Figure 4, where the surface of the substrate PVC film is altered through the microstructures of the polyethylene and siliconized paper whose engraved ridges are much sharper and less rounded. The pattern of the micro-combs is visible through the PVC film whose crests are deformed. To perfect the transfer of this pattern through the substrate, the prior art can use a thicker substrate to diminish or blunt the image transfer. Advantageously, the preferred embodiments of the present invention utilize rounded microstructured ridges or grooves that reduce or prevent the transfer of the silicone ridge patterns through a distal surface of substrates. In this way, the microstructured support of the present invention can be through reverse replication that defines the topography of the adjacent adjacent surface of the substrate while not transferring a visible image (to the naked eye) through the distal surface of the substrate. These media that use thinner substrates or surface stocks may be possible, for example, 60 im, 50 im, or 40 im or less may possibly be used, thus making savings in the cost of material since it is unnecessary to use a thickness added to decrease the visual effect caused by the use of the silicone lining in a pattern that has sharp ridges. Other tests and test results are given in the Tables 3 and 4 following. 1. Coating of a silicone grid on presilized paper The operating procedure is substantially the same as that previously used.

TABLE 3 Siliconization (with an engraving roller and a doctor bar) R630RP: mixture of polyorganosiloxanes with Roida solvent. RF310RP: mixture of polyorganosiloxanes without Roída solvent. UV902G: see Table 1 (viscosity 800 cps, axis 4, v20). UV PC900RP: see Table 1. 2. Coating of adhesive Adhesive formulations used: 1. MP 500 (Solucrilo 340: acrylic copolymer in solution in a mixture of organic solvents). Weight in grams: 24.5 g / m2 Viscosity: 135 cps (axis 4, v20, Brookfield) Drying temperature profile: 70 ° C, 90 ° C, 110 ° C, 140 ° C. Coating speed: 10 m / min. 2. MP 980 (Solucrilo 615: acrylic copolymer in solution in a mixture of organic solvents). Weight in grams: 16 g / m2 Viscosity: 790 cps (axis 4, v20, Brookfield) Drying temperature profile: 70 ° C, 90 ° C, 110 ° C, 190 ° C. Coating speed: 20 m / min.

TABLE 4 Adhesive Coating It is noted that even with a very thin substrate material (surfaces) of flexible PVC film 60 μm thick (M2629), the image of the silicon pattern being transferred is not visible.

Industrial application testing 1. Silicone coating with "reverse" engraving and polyester doctor's rod The material used, the operating conditions and the results of the tests are given in Table 5 below.

The coating of the microstructured layer of silicon is carried out through reverse engraving, that is through pyramids on the cylinder table. Characteristics of the engraving: Cylinder covered with chrome: Depth: 0.050 mm Width: 530 mm Opening: 0.100 mm Diagonal measurement of the pyramid: 0.500 mm Bottom: 0.015 mm Fixation of the microstructured layer of silicone is carried out using arc lamps of 2 Hg with an energy of 129 W / cm under an inert atmosphere of N2 (< 20 ppm of O2).

TABLE 5 Siliconization with an engraved roller and a polyester doctor bar ? I \ 3 R625DC / R620DC = Dow Corning solvent-free silicone system. UV902G = Goldschmidt UV free radical entanglement silicone system (viscosity of brookfield 800cps, axis 4, speed 20 trips / min.) 2. Adhesive coating Formulation of the adhesive used: Resin: Solucrilo 360 AB (acrylic copolymer); 720 kg. Solvent: butyl acetate 150 kg Interlacing agent: mixture of 2-pentanedione (1.5 kg), 3-isopropanol (0.8 kg), acetyl acetonate Ti (0.188 kg) and acetyl acetonate Al (2.02 kg). Viscosity: 1300 cps (axis 4, v20, Brookfield). In this way it can be seen from Table 6 that, as in the case of the tests in the pilot coating installation, they are carried out under excellent conditions, the adhesive yields and the anti-adhesive values are substantially lower than those obtained with the control test.

TABLE 6 Adhesive coating (appearance and characteristic) SS Figures 5A-5B are a scan of the electron micrograph of the microstructured silicone surface (Figure 5A) and a reverse replicated adhesive (Figure 5B) obtained according to the method of the invention in industrial application (60 x amplification with a 68 ° inclination). As in the case of the tests of the pilot installation it can be noted that the microstructured ridges are very soft and the conjunction of the rounded ridges and the depth of the relatively small ridges is around 10 μm, which cooperate enormously to reduce - Prevent the visible transfer of the microstructured silica pattern to the distal surface of the adhesive coated substrate of the flexible PVC film. Advantageously, the depths of the ridges or grooves smaller than 15 μm can be used to help reduce or prevent the undesirable visual effect. Figure 6 is a scan of the electron micrograph of the initial contact topography between the adhesive surface and the surface of the substrate support receiving the self-adhesive film micro-constructed in accordance with the method of the invention. As you can clearly see from this micrographic, and more particularly from the limited plate crest and divided into 4 squares of the same surface, the percentage of the initial contact area can be made substantially lower than the values obtained with the microstructured adhesives known to date, which are greater of 35%. Here, the contact area is approximately 25%. Depending on the appearance of the adhesives used, the composition thereof and the processing conditions, the percentages of the initial contact surface between the adhesive layer and the substrate support may vary, and in a preferred embodiment are approximately 15 to 32%, and preferably 23 to 28% of the total coated surface. In these preferred embodiments, this low level of contact surface allows better repositioning properties of the adhesive film than adhesive films of the prior art, in conjunction with good adhesion between the surface of the substrate and a support object to which it is applied. , thanks to the fact that the adhesive surface at the top of the ridges is substantially flat and will give a microreplication to the flat microplate. In addition, the presence of the microchannels thus formed of shallow (about 10 μm) and the immediate height not in contact with the adhesive surface (of about 70% or more) provides the self-adhesive product with a recolocable character in the case in which the application of the initial pressure is low. Now, if a higher pressure is exerted on the applied adhesive film, said film is immediately fixed to the surface of a support object because all the flat surfaces of the adhesive ridges in the shape of a flat plate are in contact with the surface of the object. The microchannels formed through the contact of the adhesive with the surface of the object and circumscribed through the surface of the object and the adhesive surfaces not in immediate contact with the substrate have a depth that allows easy removal and elimination of the air pockets that could occur in the adhesion interface during the application of the self-adhesive product. The simple contact of the hand on the places where the air pockets are formed can cause the rapid and complete suppression or expulsion of these air pockets. If a higher pressure is then exerted, the flat surfaces of the different adhesive plates can extend substantially over the various planes of the first silicone layer depending on the pressure exerted, the viscoelastic properties of the adhesive, the time and temperature of the adhesive. Union on a uniform and continuous surface (without the original microchannels) in close contact with the application (object). Figure 7 is a diagrammatic representation in two dimensions of the methods of the invention showing a pressilized support (1, 2) in which a layer of microstructured silicone 3 has been applied, hardened by ultraviolet radiation, as well as a microstructure three-dimensional reverse replicate obtained from the adhesive layer 10 of the substrate 11 when brought into contact with the above with the presyllized liner (1, 2), and the microstructured layer 3, and also the substrate 11 having a front material 12. As sample, it can be seen that the percentage of adhesive surface that will be immediately in contact with the surface in which the self-adhesive film was applied is 27%, its percentage is calculated as follows: Distance AB = 237 μm Distance BC = 216 μm s / S = 237 ^ = 0.27 (237 + 216) 2 It should also be noted that the adhesion interface between the adhesive surface and the application surface is substantially flat because it corresponds to the valleys formed in the first flat silicone layer of the three-dimensional microstructure. Apart from the advantage already detailed, a microstructured silicone surface can be obtained on any type of substrate, such as a cellulose paper, or non-cellulose paper (passed through a calender or glossy, dimensioned), plastic films, for example, polyester, polyolefin, polyethylene, polypropylene, polyamide (uniaxially or biaxially oriented or non-oriented, monolayer or multilayer, with or without impressions or designs, dyes, processing aids, fillers, and commonly known additives) and the advantage that silicone can be covered on the support network at a very high speed for example, greater than about 10 meters / minute (m / min), and preferably greater than 50 and even 300 m / min, the main advantages of the microconstruction method of the invention that is can obtain extremely regular microstructured patterns whose ridges can be configured (for example, small height and rounded) so as not to deform the film substrate layer (or front material) on which the microreplicated adhesive surface is applied. The main use of the microstructured adhesive is that it makes easy the application, for example, of large emblems on given surfaces. Certainly, in general you have to remove and reapply the emblem to put it better and once it is applied, you usually have to eliminate the air pockets trapped under the self-adhesive film, during the application and the gas bags that occur some times after the application. The microstructured adhesive according to the present invention allows for easy repositioning, easy bubble removal during application simply by applying manual pressure, for example, with one or more fingers or a hand, and allows removal, through microchannels formed, of any gas, which may have been typecast after the application. It will be apparent from the foregoing that the various articles of the invention can be formed in accordance with the present invention including a novel release liner, a novel pressure sensitive adhesive label having a release liner and that such articles are They can be used in a wide variety of applications including the production of very large graphic panels suitable for placement on buildings, vehicles, and billboards. Said large graphic panels may have a width of 30, 50, 100 or 150 cm or more with a length usually at least as large or as a result 1, 2, 3 or many meters more than. length. These honeycombs or leaves usually have a thickness of 1.25 millimeters (mm) or less. One embodiment of the preferred embodiment of the invention is a multilayer sheet comprising: (a) a flexible support comprising: (i) a sheet-like structure having a first broad surface and a second broad opposite surface; (ii) a first layer of a silicone containing material, for example, in a sheet-like coating that is fixed to at least the first large surface of the aforesaid sheet-like structure; (iii) a second layer of a silicone containing material fixed to the first layer (ii) as a plurality of grooves or ridges thereby providing a flexible support having at least one wide surface there and a three-dimensional topography of a plurality of opposite slots; Y - . (b) a flexible substrate having a first proximal surface and a second opposite distal surface wherein the first proximal surface is in releasable contact with the three-dimensional surface of the flexible support and the first proximal surface has an inversely replicated three-dimensional topography of pairing. The leaf-like structure of the flexible support is preferably not distorted into a plurality of edges or ridges corresponding to the grooves or ridges of the second layer, for example, through etching.

Advantageously, the second distal surface of the flexible substrate is visually free of any groove or ridge pattern corresponding to the plurality of flexible support grooves or ridges. The substrate may comprise a first adhesive layer forming a first proximal surface of the substrate, and may optionally further comprise a first layer of front material in contact with the first adhesive layer and the front material layer forming a second distal opposed layer of the substrate. The surface of the distal substrate may be printed, for example, using dyes, pigments, or dyes, with one or more images, signals or designs, or it may be unprinted, transparent, opaque, translucent, black, white, or colored, and either part or all of its surface. The distal surface of the substrate further optionally may have an additional outer protective coating or a layer applied thereto. It should be understood that the invention is in no way limited to the embodiments described and that many modifications can be made to the foregoing without exceeding the context of the present patent.

Claims (32)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for forming a three-dimensional microstructure on a flat surface of a support, characterized in that it comprises the application of a first flat and uniform silicone layer on said support surface and the application on the first silicone layer of a second three-dimensional microstructured layer of silicon, said first layer and said second layer of silicone are integrally connected so as to form a common three-dimensional microstructure, the anti-adhesive properties are regularly distributed on the support surface, so that no flexible surface of the substrate, in particular a surface of adhesive deposited on said silicone layers will be microstructured through the inverse replication of the three-dimensional microstructure formed by the two layers of silicone, wherein said silicone layers are fixed through heat hardening or through exposure to radiation ultraviole or electronics, or a combination of these.

2. A method for the three-dimensional microconstruction of a flexible substrate surface, in particular an adhesive surface, characterized in that it comprises the application of a flat and uniform first silicone layer on the surface of a support, and the application on the first silicone layer of a second three-dimensionally microstructured layer of silicone, wherein said first layer and said second layer of silicone are integrally connected to form a common three-dimensional microstructure, ensure the anti-adhesive properties regularly distributed on the surface of the support, and the deposition of the surface of the flexible substrate, in particular of the adhesive surface in said silicone layers whereby said flexible substrate surface, in particular of adhesive, is micro-constructed through the inverse replication of the common three-dimensional microstructure formed by the first layer of silicone and the second silicone layer, wherein said silicone layers are fixed through heat hardening or through exposure to ultraviolet or electronic radiation, or a combination of both.

3. The method according to any of claims 1 and 2, further characterized in that the three-dimensional microstructure formed by the first layer and the second silicone layer comprise micro-honeycomb patterns.

4. The method according to any of claims 1-3, further characterized in that three-dimensionally microstructure a surface of adhesive.

5. The method according to any of claims 1-4, further characterized in that said first silicone layer comprises a polyorganosiloxane functionalized with the groups: -SI- H as an entanglement agent, and at least one functionalized polyorganosiloxane which can react with the entanglement agent.

6. - The method of compliance with any of the claims 1-4, further characterized in that the first silicone layer comprises a polyorganosiloxane functionalized with the groups: 1 - SI - H! as an entanglement agent, and at least one polyorganosiloxane functionalized with groups | - S? - R \ which can react with the crosslinking agent, wherein R comprises at least one ethylenic unsaturation.

7. The method according to any of claims 5 and 6, further characterized in that the first silicone layer comprises a catalyst for the activation of said entanglement reaction.

8. - The method according to claim 7, further characterized in that the activation catalyst is selected from catalysts based on platinum, radium, or tin.

9. - The method according to any of claims 5-8, further characterized in that the first layer of silicone comprises, in addition to one or more additives selected from the group comprising adhesion modulators, reaction accelerators and inhibitors, pigments, surfactants and fillers.

10. The method according to any of claims 7-9, further characterized in that the first silicone layer hardens through heating or through exposure to ultraviolet radiation.

11. The method according to claim 10, further characterized in that, when the silicone layer hardens through heating, it is heated to temperatures of 70-200 ° C, advantageously 100-180 ° C.

12. The method according to any of claims 5 and 6, further characterized in that the first silicone layer hardens through exposure to electronic radiation.

13. The method according to any of claims 5-12, further characterized in that the first silicone layer has a thickness of 0.4-1.6 μm, advantageously 0.7-1.2 μm.

14. The method according to any of claims 1-13, further characterized in that said second silicone layer comprises at least one polyorganosiloxane, advantageously a polydimethylsiloxane with an acrylate function, and a ketone-type catalyst, advantageously of the benzophenone type. , and hardens through exposure to ultraviolet radiation.

15. The method according to any of claims 1-13, further characterized in that said second layer of silicone comprises at least one polyorganosiloxane, advantageously an epoxy-functional polydimethylsiloxane, and a catalyst of the iodonium salt type, and hardens through exposure to ultraviolet radiation.

16. The method according to any of claims 1-13, further characterized in that said second silicone layer comprises at least one polyorganosiloxane, advantageously a polydimethylsiloxane with an acrylate and / or epoxy function, and is hardened through exposure to ultraviolet radiation (acrylate and / or epoxy function) or electronic radiation (acrylate function).

17. The method according to any of claims 3-16, further characterized in that the three-dimensional microstructure formed through said first layer of silicone and said second layer of silicone consists of microgravure patterns, whose peak heights vary from 3. at 50 μm, advantageously from 5 to 25 μm.

18. The method according to any of claims 1-17, further characterized in that said second layer of silicone is applied to the first layer in an amount that can be in the range of 3 to 25 g / m2, advantageously 4 at 15 g / m2.

19. The method according to any of claims 1-18, further characterized in that the first silicone layer and the second silicone layer have surface tensions that are close to one another, from 15 to 25 mN / m, advantageously from 21 to 23 mN / m.

20. - The method according to any of claims 1-19, further characterized in that said substrate and support consist of paper, notably passed through a calender or sized paper, a plastic film, notably made of polyethylene, polyester, polyvinyl chloride polypropylene, polyamide.

21. The method according to any of claims 4-20, further characterized in that said adhesive is deposited on said first layer and the second layer of silicone either through direct coating on said layers or through lamination.

22. The method according to claim 20, further characterized in that, in the case of direct coating, the adhesive is either in liquid form, advantageously in an organic solvent or in an emulsion in water, or in a molten solid form. hot.

23. The method according to any of claims 4-22, further characterized in that the additive is applied to a flexible plastic film, advantageously a polyvinyl chloride film.

24. The method according to any of claims 2-23, further characterized in that during the application of said adhesive surface on any surface, the adhesive surface in contact with the above is about 15 to 32%, preferably 23 to 28% of the total coating surface.

25. A three-dimensionally microstructured film, and / or the self-adhesive film comprising a surface of adhesive such as that which is three-dimensionally micro-constructed through the method according to any of claims 1-23 and notably comprises motifs for decoration, advertising, or other purposes on the surface opposite the surface that is in contact with the microstructure formed by said layers of silicone. 26.- A multilayer sheet comprising: (a) a flexible support comprising: (i) a sheet-like structure having a first broad surface and a second large opposite surface; (ii) a first layer of a silicone containing material, for example, in a sheet-like coating that is fixed to at least the first large surface of the aforesaid sheet-like structure; (iii) a second layer of a silicone containing material fixed to said first layer (ii) as a plurality of grooves or ridges therefore provides a flexible support having at least one wide surface there and a three-dimensional topography of a plurality of opposite slots; and (b) a flexible substrate having a first proximal surface and a second opposed distal surface wherein said first proximal surface is in releasable contact with said three-dimensional surface of said flexible support and said first proximal surface has an inversely replicated three-dimensional topography of pairing . - ~: 27.- The multilayer sheet, according to claim 26, further characterized in that said leaf-like structure of said flexible support is not distorted in a plurality of grooves corresponding to said grooves of the second layer through engraving. 28. The multilayer sheet, according to claim 26, further characterized in that said second distal surface of said sensitive substrate is visually free of any pattern of slots corresponding to said plurality of slots of said flexible support. 29. The multilayer sheet according to claim 26, further characterized in that said substrate comprises a first adhesive layer forming a first surface close to said substrate. 30. The multilayer sheet according to claim 29, further characterized in that said substrate further comprises a first layer of front material in contact with said first adhesive layer and said first layer of front material forms a second distal opposed layer of said substrate. 31. The multilayer sheet according to claim 26, further characterized in that said second distal surface of said substrate has an additional outer layer applied therein. 32. The multilayer sheet according to claim 26, further characterized in that said second distal surface of said substrate is printed with at least one image.