Method and system for creating relief on a substrate

Abstract

The present invention relates to a method and system for generating a relief on a surface of a substrate (1), the method comprising applying a coating and a relief-generating material to the surface of the substrate (1), which are in contact with each other, and sublimating the relief-generating material (3).

Description

[Technical Field]

[0001] The present invention relates to a method and system for producing 3D surface reliefs or structures on a substrate, in particular by digital inkjet printing.

[0002] The invention is particularly applicable in the field of manufacturing construction and furniture products such as furniture, door and floor panels, profiles for door and window frames, etc.

[0003] The creation of relief on the surface of the substrate makes it possible to recreate the texture and surface of natural materials such as wood or stone, corresponding to the image printed on the surface of the substrate. [Background technology]

[0004] Currently, various techniques are known for producing a relief on a substrate surface by digital inkjet printing, which has the advantage that it can be produced with much greater flexibility and precision than other known techniques for producing a relief on a substrate surface, such as engraving or molding.

[0005] In a known technique for creating relief on a substrate surface by digital inkjet printing, droplets of a relief-generating material are printed onto a coating. The printed droplets create convex surfaces or protrusions in the coating by adding the relief-generating material to the coating. Alternatively, the printed droplets create concave surfaces or depressions in the coating by impact, immiscibility, or displacement of droplets of the relief-generating material ejected into the liquid coating, or when the relief-generating material mixes or dissolves with the coating, removing any mixed material or solution.

[0006] The creation of convex surfaces by digital inkjet printing has the disadvantage that the resulting relief has limited wear resistance. Furthermore, the creation of concave surfaces by digital inkjet printing has the disadvantage that the process is difficult to control to achieve sufficient relief definition due to the existence of complex physical and chemical mechanisms of interaction between the relief-generating material droplets and the coating. These mechanisms involve various variables, such as the surface tension, density, and viscosity of the relief-generating material or coating, as well as the velocity and volume of the relief-generating material droplets. Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the currently known methods, the present invention aims to provide an alternative method and system for producing a relief on the surface of a substrate, which allows to obtain a relief with sufficient wear resistance and definition in a flexible manner. [Means for solving the problem]

[0008] To achieve this objective and to solve the technical problems discussed so far, as well as to provide additional advantages that may be derived later, the present invention provides a method for generating a relief on a substrate surface, comprising applying a coating and a relief-generating material to the substrate surface, contacting the coating and the relief-generating material with each other, and sublimating the relief-generating material.

[0009] Generally, any product capable of sublimation can be used as the relief-generating material. In particular, so-called sublimation or dye-sublimable inks, which are commercially available for other known applications such as screen printing, can be used. In particular, the relief-generating material can be transparent, which allows for a neat and eye-catching relief to be obtained without the need to remove the dye of the relief-generating material.

[0010] The solid state relief-generating material is sublimated and contacts the coating, leaving voids in the coating corresponding to the areas occupied by the relief-generating material, which voids define the relief.

[0011] According to the present invention, it is conceivable that the coating and / or relief generating material is supplied to the process in a liquid state and solidifies during the process. Solidification of the relief generating material and / or coating according to the present invention can be achieved, for example, by curing or drying.

[0012] In accordance with the present invention, the relief-generating material can be applied by digital inkjet printing, which ejects ink in the form of droplets of the relief-generating material, thereby producing relief with the exceptional flexibility, speed, and definition inherent in digital inkjet printing technology.

[0013] Given that the relief-generating material is in a solid state undergoing sublimation, the relief is controlled by the variables of the sublimation process itself, and to a lesser extent by the various variables of the above-mentioned interactions between the relief-generating material and the coating, particularly if the relief-generating material is applied by digital inkjet printing. In this way, high-definition relief can be obtained in a controlled manner.

[0014] Preferably, according to the present invention, the coating and the relief-generating material contact each other when the coating is liquid or partially solidified, particularly if the relief-generating material is applied by digital inkjet printing. This facilitates the introduction of the relief-generating material into the coating, or the mixing or dilution of the relief-generating material in the coating, for example, by impact, immiscibility, or displacement. In this regard, according to the present invention, the ability to generate relief by sublimation is compatible with, and can be used in combination with, known relief-generating techniques.

[0015] The present invention contemplates both that the sublimable relief-generating material be at least partially covered or embedded in the coating, and that the sublimable relief-generating material be at least partially mixed with the coating. As the relief-generating material sublimes, and thus changes from a solid to a gas, it volatilizes out of the coating.

[0016] When the gases of the relief-generating material pass through the coating during sublimation, porous or hollow volumes are created in the coating. These porous volumes of the coating affected by sublimation are weaker than the volume of the coating that has not been penetrated by the gases of the sublimated relief-generating material, and are therefore easily removable. Removal of the sublimated coating material allows the relief to be obtained. It is also conceivable to remove the residues of the relief-generating material after sublimation, especially along with the sublimated coating material. Removal of the material can be performed by mechanical means, such as brushing or suction, and / or chemical means, such as washing or rinsing.

[0017] Preferably, according to the present invention, the coating finishes solidifying later than the relief-generating material, thereby facilitating the outgassing of the sublimated relief-generating material through the coating. To achieve this delay in solidification of the coating relative to the relief-generating material, the materials of the relief-generating material and / or the coating can be selected with appropriate compositions that, for example, influence their hardening or drying.

[0018] According to the present invention, the relief can be applied in concert with or corresponding to an image on the substrate that is applied to the substrate before or after creating the relief. The creation of the relief and the corresponding image can be done synchronously by digital inkjet printing of the relief and its image.

[0019] Preferably, the present invention contemplates both the application of the relief-generating material to the coating (i.e., after the coating has been applied) and the application of the coating to the relief-generating material (i.e., after the relief-generating material has been applied). However, any other manner in which the relief-generating material and the coating contact each other on the substrate surface is also contemplated, for example, by being applied simultaneously, in particular mixed to form one and the same coated product. According to the present invention, the coating and / or the relief-generating material can be applied by spreading it over at least an area, i.e., by covering the substrate at least partially or in a partial area.

[0020] Similarly, the present invention contemplates that the relief-generating material and coating can be applied repeatedly to obtain multiple layers of coating and relief-generating material, thereby forming a multi-layer coating. In this case, sublimation of the relief-generating material can occur after each layer and before the next layer and / or after all layers have been applied. Each layer can be configured with different parameters, such as layer thickness, amount of relief-generating material, and droplet volume of sublimation ink.

[0021] In this regard, the present invention also contemplates that other layers may be applied at least partially over the substrate, thereby resulting in a multi-layer coating with at least one coating and relief-generating layer and at least another decorative or functional layer, e.g., with different gloss levels or structures of different depths. These other layers may be applied, for example, between the coating and the relief-generating layer and / or on top of them. Similarly, the coating and relief-generating layer themselves may additionally comprise, at least partially, decorative or functional features, e.g., different gloss levels or structures of different depths.

[0022] In this way, by selectively applying coatings and / or relief-generating materials to partial areas, by applying them repeatedly, or by including other layers, multi-layer coatings can be obtained in which different decorative or technical effects, such as different glosses or reliefs, can be selectively controlled or provided.

[0023] In the context of the present invention, a relief-generating material can therefore be understood as a product that is applied in contact with a coating according to the present invention and that is configured to generate relief in the coating when at least partially sublimated. In this respect, applied relief-generating materials include at least partially sublimable products, i.e., products made of sublimable material that are at least partially sublimated by the method of the present invention to generate relief in the coating.

[0024] According to the present invention, it is contemplated that the coating and / or relief-generating material may be applied in a liquid or solid state. A solid relief-generating material may be applied, for example, by sprinkling a solid relief-generating material powder. A solid relief-generating material may be applied, for example, in the form of a solid sheet spread over the substrate surface. In this respect, the present invention contemplates all possible combinations regarding the use of at least partially liquid or solid relief-generating materials and / or coatings.

[0025] Preferably, the relief-generating material is applied in liquid form by digital inkjet printing, for example using sublimation inks, in particular the sublimation inks used in screen printing, which are suitable for the method of the present invention, as described above. Similarly, the coating is preferably applied in liquid form by roller. However, it is also contemplated that both the coating and the sublimation ink or liquid contained in the liquid relief-generating material can be applied by any other method, such as spraying, in addition to the inkjet or roller methods.

[0026] It is contemplated that sublimation is carried out by heating the relief-generating material, preferably at atmospheric pressure. Preferably, when the relief-generating material is applied by inkjet sublimation ink, the sublimation temperature of the selected sublimable product should be above a minimum threshold, taking into account that the inkjet heads used will be heated (typically to about 40°C) to obtain a suitable jetting viscosity. Similarly, preferably, the sublimable product should be selected so that its sublimation temperature is below a maximum threshold, e.g., 200°C, to prevent degradation of the materials involved in the method of the present invention, e.g., coatings and substrates.

[0027] The sublimation of the relief-generating material can be carried out by heating in any way, by radiation, by convection or by heat conduction, in particular by using an electromagnetic radiation source (e.g. by IR), a heat convection element (e.g. hot air) and / or a heat conduction element (e.g. heated element), respectively. In particular, an IR lamp can be used as an electromagnetic radiation source for heating.

[0028] According to a preferred embodiment of the present invention, it is provided that the sublimation ink or the liquid containing the relief-generating material is a dispersion, the dispersed portion containing the relief-generating material. In particular, the dispersed portion can be in liquid or solid form.

[0029] Also preferably, the relief-generating material is applied at a concentration of 10% by weight or less, preferably 1% by weight or less, especially 0.1% by weight or less in the sublimation ink or liquid from which the relief-generating material is applied, thereby allowing for a relatively low concentration of relief-generating material to be used to provide sufficient cavities in the coating to define the relief.

[0030] Similarly, the relief-generating material preferably comprises sublimable solid particles, i.e., solid particles made of a sublimable material. Typically, the sublimable solid particles can be of any size. Advantageously, a particle size (D50) of about 2000 Å or less allows their use in inkjet printheads without the need for recirculation. The smaller the size of the sublimable particles, the greater the amount of material that can be sublimated; particle sizes (D50) of about 100 Å or less are particularly preferred. In particular, particle sizes (D50) of about 10 Å or less allow for the preparation of sublimation inks or liquid solutions of the relief-generating material for application. The term D50, also referred to as the mean diameter, for quantifying the average size of particles is defined in a manner known to those skilled in the art, i.e., as the particle diameter value at which the concentration of particles with diameters larger or smaller than that value is 50% of the total particle distribution in the sample.

[0031] As mentioned above, it is contemplated that the relief-generating material and / or sublimation ink, or application liquid, is advantageously miscible with the coating, so that when the relief-generating material or sublimation ink is applied, they can be easily incorporated into the coating, which promotes further contact with each other to create the cavities that define the relief upon sublimation. To favor miscibility, it is contemplated that the sublimation ink and the coating have substantially the same polarity, and in particular that the dispersed portions of the coating and the sublimation ink have substantially the same composition.

[0032] The sublimation ink and coating mixing arrangement, in particular inkjet, allows for a higher definition of the relief to be obtained compared to other known relief generation methods in which the ejected ink liquid (e.g., by impact of droplets on the coating surface) causes a displacement of the coating liquid that defines the relief cavities. This higher definition obtained can be due to the fact that, unlike the displacement action which involves a local deformation of the coating around the cavity or impression, where liquid displaced or dislodged from the cavity accumulates, the mixture does not have such a displacement, and the relief-generating material is incorporated into the coating, and the relief is obtained by removing the mixture in a subsequent step or process.

[0033] Furthermore, the present invention provides enhanced definition as a result of the fact that, unlike a liquid, the sublimated relief-generating material is confined by its own solid state because it is in a solid state which creates cavities that define the relief upon sublimation, making the present invention particularly suitable for use in a manner that complements other known methods for obtaining relief on a substrate surface.

[0034] According to a preferred embodiment, the relief-generating material and / or sublimation ink or the coating liquid of the relief-generating material contains an electromagnetic radiation absorber, which is configured to sufficiently absorb the energy of electromagnetic radiation of a specific wavelength, particularly the electromagnetic radiation for curing the coating and / or the relief-generating material, and convert the energy into heat. Examples of electromagnetic UV radiation absorbers that can be used include benzophenones, benzotriazoles, triazines, oxanilides, and cyanoacrylates. In particular, LED or arc discharge UV lamps can be used as the electromagnetic radiation source.

[0035] According to another preferred embodiment, the relief generating material and / or sublimation ink, or the application liquid of the relief generating material, can include an exothermic chemical reaction accelerator configured to react with the coating by releasing heat. These two last embodiments of the invention improve the efficiency of heating to cause sublimation.

[0036] The present invention also contemplates that the sublimation ink or coating of the relief-generating material contains an odorant configured to penetrate the coating (2) when activated, for example, by heating. The relief-generating material itself can contain the odorant or specifically constitute the odorant (e.g., camphor can be used as a sublimable, odor-releasing product). Sublimation can draw the odor to the surface, while ensuring that the odor is retained in the coating and penetrates it.

[0037] Similarly, according to the present invention, the sublimation ink can be transparent or can contain pigments and other functional particles. By incorporating pigments or functional particles into the sublimation ink or coating liquid, the resulting relief features can be combined with the features provided by the pigments or functional particles at each application point, for example, at each drop of inkjet ink application. In this way, the combination of the resulting relief with the decorative or functional effect provided by the pigments or particles is achieved in the same step or process as the application of the sublimation ink or coating liquid.

[0038] As mentioned above, according to the present invention, the coating and / or relief-generating material can be solidified to obtain the relief, in particular at least partially solidified before the relief-generating material is sublimated. Preferably, the solidification of the coating and / or relief-generating material is carried out by curing or polymerization, preferably by electromagnetic radiation, more preferably by UV. To do this, the coating or relief-generating material is made of a curable or polymerizable material. In particular, UV lamps of the LED type or arc discharge can be used as electromagnetic radiation sources.

[0039] Partial solidification of the coating prior to sublimation, i.e., limited solidification or hardening, allows the contour defining the relief to be fixed in a specific way, holding the sublimated relief-generating material to that contour, thereby making it possible to obtain high definition of the relief. In particular, the coating finishes solidifying later than the relief-generating material, which prevents the latter from being trapped and unable to vent to the surface.

[0040] Also, as mentioned above, according to one embodiment of the method of the present invention, the relief is obtained by removing the coating affected by the sublimation of the relief-generating material and / or by removing the residue of the relief-generating material. This removed material defines the cavities left in the coating after sublimation. In this respect, in the context of the present invention, the residue of the relief-generating material can be understood as the relief-generating material that may or may not be altered after applying the sublimation step of the method of the present invention, in particular the relief-generating material that does not sublimate after applying the sublimation step.

[0041] A second aspect of the present invention provides a system for generating a relief on a substrate surface. According to the present invention, the system includes means for applying a coating to the substrate, means for applying a relief-generating material, means for sublimating the relief-generating material, and means for controlling the means for applying the coating, the means for applying the relief-generating material, and the means for sublimating. The system is configured to carry out the method described above.

[0042] The system may include means for removing the material to create the relief, which may be mechanical, for example by brushing or suction, and / or chemical, for example by washing or rinsing. It is also envisaged that the system may include means for suctioning off gases of the relief-creating material that are generated during sublimation.

[0043] Similarly, the system may include a transport means, such as a conveyor belt, for transporting the substrate between different stations where the corresponding steps of the method of the present invention are carried out as described above.

[0044] The preferred method for sublimating the relief-generating material according to the present invention is by heating. To achieve this, radiative heating means can be used, including, for example, at least one electromagnetic radiation heating lamp, especially an IR heating lamp. Alternatively or in addition, convective heating means can be used, for example, by heated air, especially by a hot air blower. Also alternatively or in addition, conductive heating means can be used, for example, by a conductive heating element, especially a heated roller or plate.

[0045] According to a preferred embodiment of the invention, the system comprises a receiving element for the sublimation material, in particular in the form of a receiving strip, facing the coating, so that when the relief-generating material is sublimated, the sublimation material and / or residues of the relief-generating material formed by the coating affected by the sublimation of the relief-generating material are applied to the surface of the receiving strip. This receiving element, preferably in the form of a strip, allows the sublimation material transferred from the coating and adhering to the receiving element to be easily removed thereafter.

[0046] According to the invention, it is also envisaged that the system may include means for cleaning the surface of the heat transfer heating element or the surface of the receiving element to which the sublimation material is applied, in particular a scraping blade for scraping said surface or receiving element.

[0047] Similarly, as mentioned above, the system may include means for removing sublimated material from the coating to create the relief. These means may be in the form of at least one brush, at least one vacuum, and / or at least one fan. It is contemplated that the system may also include means for extracting gases from the sublimation of the relief-generating material, in particular in the form of a gas extraction hood. It is also contemplated that the system may also include solidification means for at least partially solidifying the coating and / or the relief-generating material. [Brief explanation of the drawings]

[0048] The following figures are included to help illustrate various practical embodiments of the present invention and are described below by way of example and not by way of limitation. [Figure 1] 1A-1C show schematic cross-sectional views of a substrate on which a relief is obtained in steps (A) to (C) according to a first embodiment of the method or system of the present invention; [Figure 2] 2A-2C show schematic cross-sectional views of a substrate on which a relief is obtained in steps (D) to (G) according to a first aspect of a first embodiment of a method or system of the present invention. [Figure 3] 2A-2C show schematic cross-sectional views of a substrate on which a relief is obtained in steps (D) to (G) according to a second aspect of a first embodiment of a method or system of the present invention. [Figure 4] 2A-2C show schematic cross-sectional views of a substrate on which a relief is obtained in steps (A) to (C) according to a second embodiment of the method or system of the present invention; [Figure 5] 2 shows a schematic cross-sectional view of a substrate on which a relief is obtained in steps (D) to (G) according to a first aspect of a second embodiment of the method or system of the present invention; [Figure 6] 3A-3C show schematic cross-sectional views of a substrate on which a relief is obtained in steps (D) to (G) according to a second aspect of a second embodiment of the method or system of the present invention. [Figure 7] 1 shows a schematic diagram of a first exemplary embodiment of a method and system for producing a relief on a substrate surface according to the present invention, where the substrate is in the form of a panel. [Figure 8] 1 shows a schematic diagram of a second exemplary embodiment of a method and system for producing relief on a substrate surface according to the present invention, where the substrate is in the form of a continuous sheet. [Figure 9] 1 shows a detailed diagram of one embodiment of the sublimation step or process of the method and system of the present invention. [Figure 10] 1 shows a detailed view of a further aspect of the sublimation step or process of the method and system of the present invention. [Figure 11]1 shows a detailed view of a further aspect of the sublimation step or process of the method and system of the present invention. [Figure 12] 1 shows a detailed view of a further aspect of the sublimation step or process of the method and system of the present invention. [Figure 13] 1 shows a detailed view of a further aspect of the sublimation step or process of the method and system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0049] The substrate (1) can be constructed in the form of a panel or profile. The material of the substrate (1) can be selected from, for example, wood (chipboard, medium density fiberboard "MDF", high density fiberboard "HDF" or plywood), plastic (PVC), cellulosic material (paper or cardboard) or metal.

[0050] The coating (2) can be applied in liquid form by any method for applying liquid products, such as by roller, sprinkling, spraying or inkjet printing. The material of the coating (2) can be chosen, for example, from varnishes or polymeric resins.

[0051] In the embodiment of the invention shown and described in detail below, the relief generating material (3) is digitally inkjet printed and applied in the form of droplets of sublimation ink.

[0052] According to a first embodiment of the invention shown in Figures 1 to 3, starting with a substrate (A), a coating (2) is applied to its surface (B), and a relief-generating material (3) is applied to the coating (2) (C).

[0053] According to a second embodiment of the invention shown in Figures 4 to 6, starting with a substrate (A), a relief-generating material (3) is applied (B, C) directly to the surface of the substrate (1).

[0054] Referring to Figure 2, in a first aspect of the first embodiment shown in Figures 1 to 3, there is impact, immiscibility or displacement of droplets of a relief-generating material (3) with a coating (2) to generate the relief.

[0055] Referring to Figure 3, in a second aspect of the first embodiment shown in Figures 1 to 3, there is mixing or dilution of droplets of a relief-generating material (3) in the coating (2) to generate the relief.

[0056] Referring to Figure 5, in a first aspect of the second embodiment shown in Figures 4 to 6, there is impingement, immiscibility or displacement of droplets of a relief-generating material (3) with a coating (2) to generate the relief.

[0057] Referring to Figure 6, in a second aspect of the second embodiment shown in Figures 4 to 6, there is a mixing or dilution of droplets of a relief-generating material (3) in the coating (2) to generate the relief.

[0058] After contact (D) of the coating (2) with the relief-generating material (3), the coating (2) and the relief-generating material (3) are cured (E), either together or separately, to obtain solidification of at least the relief-generating material (3). Conventional curing means (10), such as heat lamps or radiation of electromagnetic radiation such as UV, IR, or electron radiation, can be used for curing.

[0059] Once solidified, the relief-generating material (3) is sublimated (F). Sublimation (F) can be achieved using conventional sublimation means (20), such as heating means, in particular hot air, or heat lamps, e.g., IR heat lamps. It is also contemplated that sublimation (F) can be achieved by reacting the relief-generating material (3) with a sublimation-activating product, e.g., by applying a sublimation-activating product to the relief-generating material (3). Sublimation (F) can be achieved, for example, simultaneously with the solidification of the coating.

[0060] Finally, material removal means (30) can be used to remove (G) the coating material in the areas affected by sublimation. These means (30) can be, for example, mechanical means such as brushing or suction, or chemical means such as washing or rinsing the area.

[0061] Figure 7 shows a processing line according to a first preferred exemplary embodiment of the present invention for obtaining a relief (7) on the surface of a substrate (1) in the form of a panel. The substrate (1) is transported (60) by a conveyor belt (63) through different steps or processes.

[0062] In the first step or process of the processing line, a liquid coating (2) consisting of UV-curable acrylic is applied to the surface of the substrate (1) in a manner known per se by rollers (70) using an application roller (71) and an addition roller (72). In a subsequent step or process, a relief-generating material (3) is applied to the coating (2) by inkjet digital printing (40) through a sublimation ink ejection head (41) using a sublimation ink containing the relief-generating material (3) dispersed in a UV-curable acrylic liquid.

[0063] In this exemplary embodiment, the sublimation ink is applied to the coating (2) while the coating (2) is still liquid, which facilitates penetration of the sublimation ink, and therefore the relief-generating material (3), into the coating (2). In a subsequent step or process of this first exemplary embodiment, the applied coating (2) and sublimation ink set are partially cured (10) by UV radiation lamps (11) to partially solidify.

[0064] Next, in a subsequent step or process, the relief-generating material (3) is sublimated (20). To do this, heat is transferred to the relief-generating material (3) by heat conduction (22) via a heated roller (221) rolling over the surface of the coating (2). This rolling is preferably synchronized with the advancement of the substrate (1) along the processing line, so that the heated roller (221) rolls over the surface of the coating (2) without substantial slippage in order to sublimate the relief-generating material (3).

[0065] During the sublimation (20), the sublimated material and / or residue of the relief-generating material (3) formed by the coating affected by the sublimation of the relief-generating material (3) is applied to the outer peripheral surface of the heated roller (221). This sublimated material is removed (50) from the outer peripheral surface of the heated roller (221) by a scraping blade (51) for scraping it off. Gases resulting from the sublimation of the relief-generating material (3) are removed (80) by a removal hood (81).

[0066] Then, in the final step or process of this first exemplary embodiment, the coating is cured by UV radiation lamps (12) to complete the solidification (10), after which a step (30) can be applied to remove excess material, such as residues of the coating and / or relief-generating material affected by sublimation of the relief-generating material, for example by brushing.

[0067] 8 shows a processing line according to a second preferred exemplary embodiment of the present invention for obtaining a relief (7) on the surface of a substrate (1), which, unlike the first exemplary embodiment, is in the form of a continuous sheet. The sheet is continuously fed from a feed coil (5) and passes through the different processes or steps of the line to a recovery coil (6), from which the sheet is recovered together with the relief (7) produced on the surface of the substrate (1) for its distribution or further processing. The sheet moves along the line by guide means, for example guide rollers, in a manner known per se.

[0068] As shown in Figure 8, the different steps or processes of this second exemplary embodiment are arranged or configured in the same manner as the steps or processes of the first exemplary embodiment. In the step or process of applying the coating by roller (70), a counter roller (71') of the coating application roller is incorporated to position the substrate (1) by counter pressure with that roller. Similarly, in the step or process of sublimation (20), a counter roller (221') of the heated roller is incorporated to position the substrate (1) by counter pressure with that heated roller.

[0069] 9 illustrates aspects of the sublimation step or process (20), illustrated for the first exemplary embodiment but equally applicable to the second exemplary embodiment. In this embodiment, unlike the examples illustrated in FIGS. 7 and 8, during sublimation (20), the sublimated material and / or residue of the relief-generating material (3) formed by the coating affected by the sublimation of the relief-generating material (3) is not applied directly to the surface of the heated roller (221), but rather to a sublimation material receiving element in the form of a receiving strip (90). The receiving strip (90) is supplied from a supply coil (93) and guided between the heated roller and the coating to a recovery coil (94), where the previously deposited sublimated material is recovered for external processing, recycling, or removal.

[0070] 9 also shows other details of the heated roller (221) system. The heated roller (221) can be moved vertically in an adjustable manner by a vertical movement actuator (224) to position the substrate (1) by applying counter pressure with the counter roller (221') to approach the coating (2) having the applied relief-generating material (3) thereon. The heated roller (221) is equipped with a rotation actuator (223) to rotate the heated roller (221) and the receiving strip (90) on the surface of the coating (2) in synchronization with the advancement of the substrate (1), preferably creating a substantially slip-free rotation, while the advancement of the receiving strip (90), sandwiched between the heated roller (221) and the coating (2), occurs as the sublimation material is transferred to the receiving strip (90). A conveyor belt (63) is provided to transport (60) the substrate (1) in its advance, the conveyor belt (63) being guided by guide rollers (61, 62) and driven in the exemplary embodiment by a rotary actuator (64) which acts to rotate one of the guide rollers (62).

[0071] Figure 10 shows another aspect of the sublimation step or process (20), which is also shown for the first exemplary embodiment but which can be applied to the second exemplary embodiment as well. In this embodiment, unlike the aspect shown in Figure 9, the receiving strip (90) is continuously fed in a closed path guided by a guide roller (91). The guide roller (91) can be moved vertically by a vertical movement actuator (95) to adjust the position of the guide roller (91) facing the coating (2), allowing the substrate (1) to advance between this guide roller (91) and an opposing roller (91'). The receiving strip (90) is moved by a rotation actuator (92), for example, by rotating the guide roller (91) facing the coating (2).

[0072] Similar to the embodiment shown in Figure 9, in the embodiment of Figure 10 the sublimation material is transferred to a receiving strip (90), but in this embodiment the receiving strip (90) is re-fed after being cleaned (50) of any sublimation material previously deposited thereon. The cleaning (50) can be performed, for example, as Figure 10 shows, by a scraping blade (51) for scraping the receiving strip (90), i.e., the surface of the receiving strip (90) that contacts the coating (2) when the sublimation material is transferred thereto.

[0073] 10 also shows a sublimation means alternative to or complementary to the heated roller (221) shown in the embodiment described above. In this embodiment, heating to cause sublimation (20) can be performed by thermal convection in the area of ​​the guide roller (91) facing the coating (2) by a strip of receiving strip (90). In particular, the strip (90) can be made of a material, such as a metal, that facilitates local heat conduction in the coating (2) and / or can be heated.

[0074] Figure 11 shows another aspect of the sublimation step or process (20), similarly illustrated for the first exemplary embodiment, but which can be applied to the second exemplary embodiment as well. In this aspect of the embodiment, unlike the aspect shown in Figure 10, sublimation is achieved by radiant heating (21). Heating can be achieved directly on the coating (2) through a receiving strip (90) of sublimation material that is transparent to the passage of radiation, or indirectly by heating the receiving strip (90).

[0075] As can be seen in Figure 11, heating (21) is performed between two guide rollers (91) facing the coating (2) at two successive positions, so that the receiving strip (90) remains in continuous contact with the coating (2) between the two positions. This allows for smoothing of the surface of the coating (2) simultaneously with heating (21). Instead of or complementing heating (21), partial solidification (10) can be performed by UV-radiation lamps (211) through the receiving strip (90), which is transparent to that radiation. In this way, more efficient curing can be achieved, since the amount of air present between the strip (90) and the coating (2) in that area is reduced.

[0076] 12 shows another aspect of the sublimation step or process (20), illustrated for the first exemplary embodiment but equally applicable to the second exemplary embodiment. In this embodiment, unlike the previous aspects, heating of the coating to effect sublimation (20) is performed by a heat-conducting element (22) in the form of a heating plate (222). The heating plate (222) is vertically movable by a vertical movement actuator (225) so that the plate (222) faces the coating (2) with the relief-generating material (3) until it contacts the coating (2) to heat it and cause it to sublimate, and the substrate (1) is located between the plate (222) and a counter roller (222'). Cleaning (50) of the sublimated material transferred to the plate (222) is performed by a scraping blade (51) that can be moved horizontally to scrape off the sublimated material, which is then deposited in a collection tray (52) for the removed material.

[0077] Figure 13 shows another aspect of the sublimation step or process (20), shown for the first exemplary embodiment but equally applicable to the second exemplary embodiment. In this embodiment, unlike the aspect shown in Figure 12, there is a sublimation material receiving strip (90) positioned between the plate (222) and the coating (2) to receive the sublimated material from the coating (2). The receiving strip (90) is cleaned (50) of the sublimated material by a scraping blade (51).

[0078] The present invention is not limited to the embodiments shown, but includes all embodiments, modifications and combinations that fall within the scope of the appended claims.

[0079] Thus, for example, in accordance with the present invention, heating to cause sublimation (20) can be performed in a single step or process, or in multiple steps or processes, successive or alternating with other steps or processes of the method of the present invention. In this regard, it is contemplated that gradual heating of the coating (2) before sublimation begins can be achieved by multiple conductive heating elements (22), such as, for example, heated rollers (221).

[0080] Examples of practical embodiments As an example, caffeine or camphor were used as sublimable products to obtain examples of practical embodiments of each of them according to the present invention.

[0081] Starting from commercially available sublimation products in powder form, these powders have various particle sizes and even have some parts that have hardened or aggregated due to moisture. This powder was ground to obtain a sublimation product powder with a particle size (D50) of 2000 Å. The ground sublimation product was then dispersed in a dispersant consisting of an acrylic liquid that partially inhibits UV curing to make a colloidal solution with a sublimation product concentration of about 5% by weight of the sublimation ink, and a sublimation ink that can be used by inkjet printing was obtained.

[0082] The sublimation ink was printed by inkjet printing according to a digital relief template onto a liquid coating of UV-curable acrylic varnish that had been applied to the surface of a wooden substrate. Printing was carried out with printheads sold under the trademark Seiko 1536RC (with recirculating head) and the same trademark Seiko 508GS (without recirculating head).

[0083] Once the sublimation ink was applied, the samples with the applied coating and relief-generating material were exposed to UV radiation by an electric arc discharge lamp until the coating was partially cured and a maximum degree of cure of about 40% (relative to the exposure energy required to fully cure the coating) was reached. The samples were then heated by exposure to IR radiation by an IR lamp until a coating temperature of about 160°C was reached for samples in which the sublimation product was caffeine and about 150°C for samples in which the sublimation product was camphor.

[0084] The heating caused the sublimable product to sublimate, resulting in weakening of the coating in areas of the coating that defined the resulting relief (void areas as a result of the release of gases due to sublimation). The sample was then final cured for its complete solidification.

[0085] Finally, a brush was applied to the entire surface of the coating to remove areas of the coating that had been weakened by the effects of sublimation, consisting of residues of the coating and / or applied sublimation ink affected by the sublimation of the sublimation product, and as material was removed from its interior, cavities corresponding to those areas were exposed, resulting in relief. [Explanation of symbols]

[0086] 1 Base material 2. Coating 3. Relief natural wood 4. Relief Cavity 5. Continuous sheet-form substrate supply coil 6. Continuous sheet-form substrate recovery coil 7. Obtained relief 10 Solidification means 11 Initial curing UV lamp 12 UV lamp for final curing 20 Sublimation means 21 Electromagnetic Radiation Heat Lamp 211 UV Heat Lamp 22 Conduction Heating Elements 30 Coating material removal means 31 Suction machine for removing coating material 40 Inkjet digital printing methods 41 Inkjet print head 50 Sublimation material cleaning means 51 scraping blade 52 Sublimation material collection tray 60 Substrate conveying means 61 First guide roller for belt conveyor 62 Second guide roller for conveyor belt 63 Base material conveyor belt 64 Rotation actuator for guide rollers for belt conveyors 70 Liquid coating application means 71 Liquid coating application roller 71' Counter roller for application roller 72 Liquid coating addition roller 80 Means for extracting gas by sublimation 81 Sublimation gas extraction hood 90 Sublimation Material Receiving Strips 91 Guide roller for receiving strip of sublimation material 91' Counter roller for guide roller of receiving strip 92 Rotation actuator of guide roller of receiving strip of sublimation material 93 Sublimation material receiving strip supply coil 94. Recovery coil for receiving strip of sublimation material 95 Guide roller vertical movement actuator 221 Heat conduction heating roller 221' Heating roller counter roller 222 Heat Conduction Heating Plate 222' Heat conduction heating plate counter roller 223 Heating roller rotation actuator 224 Heating roller vertical movement actuator 225 Heating plate vertical movement actuator

Claims

1. applying a coating (2) and a relief-generating material (3) to a substrate (1), wherein said coating (2) and said relief-generating material (3) are in contact with each other; sublimating said relief-generating material (3) to leave cavities in said coating (2) corresponding to areas previously occupied by said relief-generating material (3) in contact with said coating (2); wherein said cavities define a relief, and said relief-generating material (3) is applied by digital inkjet printing.

2. 2. A method for creating a relief on a surface of a substrate (1) according to claim 1, wherein said coating (2) is applied to said relief-creating material (3).

3. 2. A method for creating a relief on a surface of a substrate (1) according to claim 1, wherein said relief-creating material (3) is applied to said coating (2).

4. 4. A method for creating a relief on the surface of a substrate (1) according to any one of claims 1 to 3, comprising, after sublimating the relief-generating material, removing residues of the coating and / or the relief-generating material affected by the sublimation of the relief-generating material.

5. 5. A method for creating a relief on the surface of a substrate (1) according to any one of claims 1 to 4, wherein the relief-creating material (3) is applied to the surface of the substrate (1) in accordance with an image printed thereon.

6. 6. A method for creating a relief on the surface of a substrate (1) according to any one of claims 1 to 5, wherein the relief-creating material (3) is transparent.

7. 7. A method for creating a relief on the surface of a substrate (1) according to any of claims 1 to 6, wherein the coating (2) and / or the relief-creating material (3) is applied to the substrate (1) in liquid form.

8. 8. The method for creating a relief on the surface of a substrate (1) according to claim 7, wherein the coating (2) and the relief-creating material (3) come into contact with each other when the coating (2) is liquid or partially solidified.

9. 9. A method for creating a relief on the surface of a substrate (1) according to any of the preceding claims, wherein the coating (2) and / or the relief-creating material (3) is solidified.

10. 10. The method for producing a relief on the surface of a substrate (1) according to claim 9, wherein the coating (2) and / or the relief-generating material (3) is at least partially solidified before the relief-generating material (3) is sublimated.

11. 11. The method for generating a relief on the surface of a substrate (1) according to claim 9 or 10, wherein the solidification of the coating (2) and / or the relief-generating material (3) is carried out by curing, preferably by curing with electromagnetic radiation, preferably UV.

12. 12. A method for creating a relief on the surface of a substrate (1) according to any of claims 9 to 11, wherein the coating (2) finishes solidifying later than the relief-creating material (3).

13. 13. A method for creating a relief on a surface of a substrate (1) according to any one of claims 1 to 12, wherein the relief-creating material and the coating are repeatedly applied to obtain multiple layers of the coating and the relief-creating material.

14. 14. A method for producing a relief on the surface of a substrate (1) according to any of claims 1 to 13, wherein the sublimation of the relief-producing material (3) is carried out by heating, in particular by an electromagnetic radiation source, more in particular by IR, by a heat convection element, more in particular by hot air, or by a heat conduction heating element.

15. 15. A method for creating a relief on the surface of a substrate (1) according to any of the preceding claims, wherein the relief-creating material (3) is applied by using sublimation ink.

16. 16. The method for producing a relief on the surface of a substrate (1) according to claim 15, wherein the relief-producing material (3) and / or the sublimation ink are miscible in the coating (2).

17. 17. A method for producing a relief on the surface of a substrate (1) according to claim 15 or 16, wherein the sublimation ink is a dispersion, the dispersion comprising the relief-producing material (3).

18. 18. A method for producing a relief on a surface of a substrate (1) according to any of claims 1 to 17, wherein the relief-producing material comprises sublimable solid particles.

19. 19. A method for producing a relief on the surface of a substrate (1) according to claim 18, wherein the sublimable solid particles have a size (D50) of less than or equal to 2000 Å, preferably less than or equal to 100 Å, in particular less than or equal to 10 Å.

20. 20. A method for producing a relief on the surface of a substrate (1) according to any of claims 15 to 19, wherein the relief-producing material (3) has a concentration of sublimation ink when applied of 10% by weight or less, preferably 1% by weight or less, in particular 0.1% by weight or less.

21. 21. The method for generating a relief on the surface of a substrate (1) according to any of claims 15 to 20, wherein the sublimation ink comprises an electromagnetic radiation absorber configured to sufficiently absorb the energy of electromagnetic radiation, in particular electromagnetic radiation, irradiated at a defined wavelength and convert said energy into heat in order to cure the coating (2) and / or the relief-generating material (3).

22. 22. The method for producing a relief on the surface of a substrate (1) according to claim 21, wherein the electromagnetic radiation absorber is for UV and is selected in particular from the group consisting of benzophenones, benzotriazoles, triazines, oxanilides and cyanoacrylates.

23. 23. The method for producing a relief on a surface of a substrate (1) according to any of claims 15 to 22, wherein the sublimation ink comprises an exothermic chemical reaction accelerator configured to react with the coating (2) by releasing heat.

24. 24. The method for producing a relief on a surface of a substrate (1) according to any of claims 15 to 23, wherein the sublimation ink comprises an odorant configured to impart an odor to the coating (2) when activated by heating.

25. A system for producing a relief on a surface of a substrate (1), comprising: means (70) for applying a coating to said substrate (1); means (40) for applying the relief-generating material (3); means (20) for sublimating the relief-generating material (3); 25. A system for generating a relief on a surface of a substrate (1), comprising: a coating (2), a coating (3), a means (40) for applying the relief-generating material (3), and a means for controlling the coating (2), the means for applying the relief-generating material (3), and the means for sublimating the relief-generating material (3), wherein the system is configured to perform a method according to any one of claims 1 to 24.

26. 26. The system for generating a relief on the surface of a substrate (1) according to claim 25, wherein the means (20) for sublimating the relief-generating material (3) comprises at least one electromagnetic radiation heating lamp (21), in particular an IR heating lamp, at least one convection heating element, in particular a hot air blower, and / or at least one heat conduction heating element (22), in particular a roller (221) or a plate (222).

27. 27. A system for generating a relief on the surface of a substrate (1) as described in claim 25 or 26, comprising a receiving strip (90) of sublimation material facing the coating (2), such that when the relief-generating material (3) is sublimated, the sublimation material formed by the coating affected by the sublimation of the relief-generating material (3) and / or residues of the relief-generating material (3) are applied to the surface of the receiving strip.

28. 28. A system for producing a relief on the surface of a substrate (1) according to claim 26 or 27, comprising means (50) for cleaning the surface of the heat-conducting heating element (22) or the surface of the receiving strip (90) on which the sublimation material is applied, in particular a scraping blade (51) for scraping said surface or said strip.

29. 29. A system for generating a relief on the surface of a substrate (1) according to any one of claims 26 to 28, comprising means (30) for removing from the coating (2) sublimated material formed by the coating affected by sublimation of the relief-generating material (3) and / or for removing residues of the relief-generating material (3), in particular said means (30) in the form of at least one brush, at least one suction device (31) and / or at least one blower.

30. 30. A system for generating a relief on the surface of a substrate (1) according to any one of claims 25 to 29, comprising means (80) for removing gases from the sublimation of the relief-generating material (3), in particular in the form of a gas removal hood (81), and / or solidification means (10) for at least partially solidifying the coating (2) and / or the relief-generating material (3), and / or substrate transport means (60) for transporting the substrate (1) during the implementation of the method.

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