EP3666525A1 - Method and device for producing a structured surface - Google Patents

Abstract

A method for producing a decorative surface on a workpiece (1) is disclosed, comprising the following steps: - feeding (S10) the workpiece (1), which is coated with a liquid layer (2), to a digital printing station; - applying ( S12) an agent which is designed to at least partially absorb electromagnetic radiation, at least on a partial surface of the surface of the liquid layer (2), or which in contact with the surface gives rise to a reaction product which is of such a nature that it is electromagnetic Can at least partially absorb radiation; - Irradiate (S14) the surface of the liquid layer (2) and the agent with electromagnetic radiation with variable wavelength. Furthermore, a device (18) for performing this method is disclosed.

Description

The present invention relates to a method and a device for producing a decorative surface, in particular on a workpiece.

It is the goal of all decorative surfaces or decorative coated surfaces to look as natural as possible. To achieve this, chipboard, MDF, HDF, plastic or external facades, e.g. Metal sheets or plastic sandwich structures and similar plates with a replica of a natural material, e.g. Wood, stone, the surface is then provided with a three-dimensional structure (feel) according to the prior art.

This haptic is often applied synchronously with the underlying decor image. This means that with a wood reproduction, e.g. a printed knothole is covered with a recess provided in the overlying, embossed structure, while higher-lying areas from the wood look do not receive an embossed recess.

Such a structure is also called a synchronous pore. This synchronous pore can take place in an analog way by means of an embossing die which is matched to a decorative image and which is in a press, for example in a cycle press or a continuous double belt press (cf. DE 103 16 695 B4 ) is laid out precisely.

The patent EP 3 109 056 B1 shows a method in which such a synchronous structure can be applied very flexibly in a lacquer layer according to a digital template.

With all of these methods, it is very desirable not only to be able to feel the decorative and printed image as well as the structure (feel), but also to recognize it visually. This means that with the three-dimensional structuring, a difference in gloss level should be achieved between the lower areas (pores) and the higher areas. The gloss level is determined here in accordance with the method according to DIN EN ISO 2813: 2015-02. For the gloss measurement, a quantity of light is measured that reflects a surface in relation to a reference standard made of polished glass. The unit of measurement used is GU (Gloss Units). The amount of light reflected on the surface depends on the angle of incidence and the properties of the surface. When measuring gloss, different angles of incidence (20 °, 60 ° and 85 °) can be used to determine the degree of reflection, preferably measuring with the angle of incidence of 60 °. Alternatively, the mean value of measurements at the three angles of incidence can also be used. The reflectance compares the light energy emitted and received by a gloss meter in percent at a certain angle of incidence.

All surfaces or sections of surfaces that achieve less than 20 gloss units when measured with a gloss level meter are defined as "matte" and all surfaces or sections of surfaces that achieve more than 60 gloss units are defined as "glossy" designated. One of the two layers of paint can be matt and the other glossy.

In order to use the digital process to make such a difference in the highlights from the shiny spots to the less shiny spots e.g. To achieve 20 gloss points difference, preferably less than 10 gloss points difference, it is known to work with different digitally applied lacquers and the different degrees of gloss produced thereby. However, this process is very complex since different paints have to be used.

Furthermore, the change in the degree of gloss of an at least not completely solidified, in particular liquid, layer from one is from the prior art plastic which has not yet been polymerized and which is excited to polymerize by irradiation with high-energy electromagnetic radiation having a wavelength of less than 300 nm, preferably less than 250 nm. Because of the polymerization only in the upper layer of this liquid layer, which was applied, for example, with a layer thickness of 50 μm (polymerization takes place, for example, only in a layer of less than 0.1 μm, preferably less than 0.01 μm) through the polymerization of this thin layer, a kind of "skin" on the still liquid layer underneath. The result of this skin is wrinkling in the micro or nano range, which ultimately causes the matting of this surface, since, compared to an untreated layer, it increasingly scatters incident light in several spatial directions.

This process is known, for example, from the product area of "Innovative Oberflächentechnologies GmbH".

With this matting process, however, the resulting surface is evenly matted and has the same degree of gloss or mattness at all lower and higher points. Especially with wood reproductions with a very low gloss level (very deep matt) of e.g. less than 5, preferably less than 3 gloss points, the structure depths previously applied by the known methods of e.g. 10 to 50 µm height difference between the deeper pores and the higher areas can no longer be visually recognized.

It is therefore the object of the present invention to demonstrate a method and a device with which a decorative surface can be produced very flexibly without including the disadvantages of the various lacquers required.

This task is solved by the independent claims. Advantageous further developments are the subject of the dependent claims.

• Zuführen des Werkstückes, das mit einer flüssigen Schicht beschichtet ist, zu einer digitalen Druckstation;
• Aufbringen eines Mittels, das dazu ausgebildet ist, elektromagnetische Strahlung zumindest teilweise zu absorbieren, zumindest auf eine Teilfläche der Oberfläche der flüssigen Schicht, oder welches in Kontakt mit der Oberfläche ein Reaktionsprodukt entstehen lässt, das derart beschaffen ist, dass es elektromagnetische Strahlung zumindest teilweise zu absorbieren vermag;
• Bestrahlen der Oberfläche der flüssigen Schicht und des Mittels mit elektromagnetischer Strahlung mit einer Wellenlänge von weniger als 300 nm, bevorzugt weniger als 250 nm, besonders bevorzugt weniger als 200 nm;

In order to be able to generate these gloss differences and at the same time to influence the degree of gloss by means of the micro-folding described above by means of the high-energy, electromagnetic radiation with a wavelength of less than 200 nm, the method according to the invention proposes the following procedure:
According to the invention, a method for producing a decorative surface on a workpiece is provided with the following steps:

• Feeding the workpiece coated with a liquid layer to a digital printing station;
• Applying an agent which is designed to at least partially absorb electromagnetic radiation, at least to a partial surface of the surface of the liquid layer, or which, in contact with the surface, gives rise to a reaction product which is such that it at least partially admits electromagnetic radiation can absorb;
• Irradiating the surface of the liquid layer and the agent with electromagnetic radiation with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm;

In order to make the method flexible, electromagnetic radiation with different wavelengths is preferably used in a different time sequence. A wavelength of less than 200 nm is preferably used first, then a wavelength of less than 250 nm and finally a wavelength of less than 300 nm.

The agent is preferably sprayed onto the liquid layer in the form of fine droplets and / or applied in the form of droplets, in particular by means of a digital print head or a digital nozzle bar.

The chemical and / or physical properties of the agent are preferably designed to absorb at least 10%, preferably at least 30%, particularly preferably at least 50% of incident electromagnetic radiation.

The higher the absorption property of the agent, the less of it has to be applied to the liquid layer in order to achieve the same absorption effect. A good absorption property thus enables the process to be operated economically.

In this application, the fine droplets preferably form a uniform layer on the surface of the liquid layer when they are applied, and are particularly suitable for large-area application.

The fine droplets in particular have a volume of 0.1 pl to 1 pl, preferably 0.3 pl to 0.8 pl, particularly preferably 0.5 to 0.6 pl.

The droplets in particular have a volume of 1 pl to 80 pl, preferably 3 pl to 12 pl, particularly preferably 5 pl to 10 pl.

The velocity of the droplets and / or the fine droplets is in particular between 0.5 m / s and 12 m / s, preferably between 3 m / s and 7 m / s, particularly preferably between 5 m / s and 6 m / s.

In one embodiment, the surface of a liquid layer on a workpiece is sprayed with droplets of an agent in the form of a liquid before the still liquid lacquer layer is irradiated with the high-energy, electromagnetic radiation with a wavelength of less than 200 nm. to at least partially absorb the high-energy, electromagnetic radiation. The result of this is that the polymerization in the surface of the layer underneath and droplets does not polymerize, or polymerizes much less, at the points where the surface has been sprayed with the droplets, and the degree of mattness is therefore different, preferably less, than at those not the droplets sprayed surfaces.

The droplets and / or the fine droplets are preferably dispensed in such a way that they at least hit the surface of the liquid layer when they hit it partially penetrate, and / or come to rest on it and / or displace it and introduce depressions, the droplets being adjusted in particular in volume and / or speed in order to influence the depth of penetration and the displacement.

The delivery of the fine droplets is preferably controlled in such a way that their impulse when they strike the surface of the liquid layer is not sufficient to at least partially overcome the surface tension and / or the viscosity forces of the liquid layer, so that the fine droplets preferably on the surface of the liquid layer come to rest.

The delivery of the droplets is preferably controlled in such a way that their impulse when they strike the surface of the liquid layer is sufficient to at least partially overcome the surface tension and / or the viscosity forces of the liquid layer, so that the liquid layer is displaced by the droplets, whereby a structure of 10 to 50 µm difference in height can be introduced into the liquid layer.

By irradiating the surface of the liquid layer with the electromagnetic radiation, with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm, a microstructure or a nanostructure is preferably created in the surface of the uppermost partial area the liquid layer is formed by microfolding, which scatters the reflection of incident light and thus creates an optically matt impression. The microfolding of the uppermost partial surface of the liquid layer is caused by polymerization of the same, as described in the introduction.

To enable this process to be carried out, the liquid layer preferably consists of a polymerizable acrylate mixture. It also preferably has radiation-curing properties.

The liquid layer can alternatively be designed as an aqueous or solvent-based coating system, which can be dried, for example, by means of a nozzle dryer.

In a specific exemplary embodiment, the liquid layer consists of an acrylate lacquer with 30% by weight of a bi-acrylate HDDA, 40% by weight of a bi-acrylate DPGDA, 10% by weight of a cross-linker TM PTA, 3% by weight of an industry-standard photoinitiator and 17 % By weight of other ingredients. The acrylate varnish has a viscosity of 80-500 mPas, preferably 150-400 mPas, measured at 25 ° C and normal pressure with a rheometer.

Furthermore, the agent applied preferably consists of a polymerizable acrylate mixture and / or of a solvent-containing liquid and / or of an aqueous mixture, in particular with a water content of more than 30%, preferably more than 50%.

The layer is preferably cured by irradiation with electromagnetic radiation, with a wavelength preferably greater than 250 nm, particularly preferably greater than 300 nm, and / or by irradiation with electron radiation and / or by active and / or passive drying.

Active drying is understood below to mean any type of drying in which the liquid layer is dried by creating special conditions. Thus, the liquid layer can be dried, in particular by means of an inflow with a fluid, in particular air, and / or by supplying heat, in particular by means of IR radiation or by using a heater.

Passive drying, on the other hand, is preferably characterized in that the liquid layer cures on its own and without further processing. This can be done, for example, by transporting the workpiece on a free section of a belt conveyor and / or by depositing the workpiece.

The curing preferably takes place by means of reaction curing by means of, for example, a two-component system which cures by chemical reaction between the components within less than 30 minutes, preferably less than 5 minutes.

• einen Stoff aus der Gruppe der gehinderte Amine in einer Konzentration von 0 - 20%
• einen Stoff aus der Gruppe der N,N'-Diphenyleoxamide in einer Konzentration von 0 - 20%.

The applied agent preferably consists only of water or, in addition to water with a total proportion of 10-99%, it has at least one of the following ingredients in the stated concentration (% by volume):

• a substance from the group of hindered amines in a concentration of 0-20%
• a substance from the group of N, N'-diphenyleoxamides in a concentration of 0-20%.

• einen Stoff aus der Gruppe der gehinderte Amine in einer Konzentration von 0 - 20%
• einen Stoff aus der Gruppe der N,N'-Diphenyleoxamide in einer Konzentration von 0 - 20%.

In addition to an alcohol and / or a glycol with a total proportion (alcohol and / or glycol) of 10-99%, the agent applied preferably has at least one of the following ingredients in the stated concentration (% by volume):

• a substance from the group of hindered amines in a concentration of 0-20%
• a substance from the group of N, N'-diphenyleoxamides in a concentration of 0-20%.

• einen Stoff aus der Gruppe der Benzophenone in einer Konzentration von 0 - 15%
• einen Stoff aus der Gruppe der Benzotrialzole in einer Konzentration von 0 - 15%.

In addition to a polymer content of 10-99%, the applied agent preferably has at least one of the following ingredients in the stated concentration (% by volume):

• a substance from the group of benzophenones in a concentration of 0 - 15%
• a substance from the group of benzotrialzenes in a concentration of 0 - 15%.

Furthermore, the agent applied is preferably such that it is particularly preferred, in particular after irradiation with electromagnetic radiation, in particular of less than 300 nm, preferably of less than 250 nm of less than 200 nm, evaporated within less than 3 minutes, preferably within less than 1 minute, particularly preferably within less than half a minute.

The faster the agent evaporates again from the surface of the liquid layer after it has been applied or after the above-mentioned irradiation, the faster it is possible to switch to the next processing step, which has advantages in terms of cycle time and production speed.

A further step in processing the method is particularly preferably provided, in which the evaporation of the agent is carried out within less than 3 minutes, preferably within less than 1 minute, particularly preferably within less than half a minute.

Such an evaporation step can in particular be designed in such a way that the workpiece with the agent applied to the liquid layer is conveyed through an appropriately set-up section which has special evaporation conditions for the agent.

The evaporation of the agent can in particular take place actively, the agent being evaporated by creating special conditions. Thus, the agent can be evaporated, in particular by means of a flow with a fluid, in particular air, and / or by supplying heat, in particular by means of IR radiation or by using a heater.

Alternatively or additionally, the agent can also evaporate alone and without further processing. This can be done, for example, by transporting the workpiece on a free section of a belt conveyor and / or by storing the workpiece, the further processing taking place after evaporation.

The agent preferably undergoes a chemical reaction when it hits the surface or when it comes into contact with the surface of the liquid layer that there is an optical and / or haptic change in the surface at the points.

This can preferably be done by polymer formation of the surface of the liquid layer together with the agent, this being triggered and / or intensified in particular by irradiation with electromagnetic radiation. The polymer formation changes, for example, the reflective property of the surface of the liquid layer and / or its roughness.

A chemical reaction step is particularly preferably provided which is designed such that the chemical reaction between the agent and the layer is given sufficient time for this chemical reaction to take place at least partially.

Such a chemical reaction step can in particular be designed in such a way that the workpiece with the agent applied to the liquid layer is conveyed through an appropriately set-up section which has special reaction conditions for the agent and the liquid layer.

This can be achieved, for example, by supplying heat, in particular by means of IR radiation, or by using a heater.

The chemical reaction is preferably designed in such a way that a reaction product which has an absorption property with respect to electromagnetic radiation is formed on impact or in further contact between the medium and the liquid layer.

Preferably, the applied agent also undergoes a chemical reaction when it hits the layer in such a way that the reaction product at this point is irradiated with electromagnetic radiation with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably of less than 200 nm, no or less microstructure formation than on the areas on which no agent has been applied to the surface.

A further step is preferably also provided in which the liquid layer is applied to a surface of the workpiece.

This can be done, for example, by roller application, in which the surface of the workpiece is coated with the liquid layer over the entire surface or over partial surfaces to be structured. Alternatively, the application can also be carried out by means of a spray head, which applies the liquid layer to the surface of the workpiece by means of nozzles.

Another step, in particular for applying the agent, is preferably part of the method in which the liquid layer is structured by means of an analog or digital structuring method, whereby in particular a structure of the liquid layer with a height difference of 10 to 50 μm is achieved.

A further step is preferably also provided in which the liquid layer is structured by means of an analog structuring method, in particular with an embossing roller or plate, and / or by means of analog or digital application, in particular by means of a digital printhead, displaced by structuring droplets, whereby by the structuring depressions are introduced into the layer.

The structuring droplets in particular have a volume of 1 pl to 80 pl, preferably 3 pl to 12 pl, particularly preferably 5 pl to 10 pl.

The speed of the structuring droplets is in particular between 1 m / s and 12 m / s, preferably between 3 m / s and 7 m / s, particularly preferably between 5 m / s and 6 m / s.

The structuring droplets preferably consist of the same material as the liquid layer, so that their impact on the liquid layer merely results in a physical displacement for structuring the liquid layer.

Alternatively or additionally, structuring droplets can also be applied which differ from the liquid layer in their composition, in particular in their density. It is also conceivable to design these structuring droplets in such a way that they react chemically with the surface of the liquid layer in order to achieve an optical and / or haptic change in this surface.

It is also conceivable that the structuring of the liquid layer is carried out in such a way that this structure is formed as synchronously as possible (i.e. with a maximum deviation of 2 mm, preferably 1 mm) to a decorative image applied to the workpiece under the liquid layer. I.e. If a wood grain is depicted on the workpiece, the wood grain is also reproduced with the structuring, which corresponds to the grain of the decor image. The layer is then preferably at least partially transparent at the latest after curing, so that the decorative image is correspondingly visible.

A further step can preferably also be provided, in which a decorative image is applied to the workpiece, for example by means of digital printing. Alternatively, a decorative image can also be applied to a structured layer that is at least partially cured or that has a surface that is solidified by polymerization. This decorative picture can be designed in one or more colors.

The method steps described here are not to be seen as limiting the subject matter of the method according to the invention. Rather, other methods can be obtained by swapping, repeating or omitting individual steps. For example, after the first coating with a liquid layer, a further coating with a liquid layer can also take place, which is also matted in order to achieve special optical effects.

• eine Transportvorrichtung mit einer Haupttransportrichtung, wobei die Transportvorrichtung dazu ausgebildet ist, ein Werkstück, das mit einer flüssigen Schicht beschichtet ist, zu weiteren Elementen der Vorrichtung zu transportieren,
• eine Abgabevorrichtung, die dazu ausgebildet ist, ein Mittel zumindest auf eine Teilfläche der Oberfläche der flüssigen Schicht aufzubringen;
• eine Strahlenquelle, die dazu ausgebildet ist, die Oberfläche der flüssigen Schicht mit elektromagnetischer Strahlung mit einer Wellenlänge von weniger als 300 nm, vorzugsweise weniger als 250 nm, besonders bevorzugt weniger als 200 nm, zu bestrahlen.

According to the invention, a device which is suitable for carrying out the method according to the invention is also provided with the following elements:

• a transport device with a main transport direction, the transport device being designed to transport a workpiece which is coated with a liquid layer to further elements of the device,
• a dispenser configured to apply an agent to at least a portion of the surface of the liquid layer;
• a radiation source which is designed to irradiate the surface of the liquid layer with electromagnetic radiation having a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm.

The device preferably has a curing station, which can be designed differently in order to achieve curing of the at least partially liquid layer.

For this purpose, a radiation source can preferably be provided, which is designed to irradiate the liquid layer and / or the applied agent with electromagnetic radiation of variable wavelength, in particular with IR radiation, at least until it is partially cured.
The radiation source is preferably formed separately and / or is identical to the radiation source which emits the electromagnetic radiation with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm.

Alternatively or additionally, the radiation source can emit electron radiation of variable wavelength.

Furthermore, the curing station preferably has a fluid source which is designed to flow around the layer, in particular with air, the fluid being able to be influenced in particular in the parameters of flow rate and / or temperature and / or moisture.

Furthermore, the curing station preferably has an electron beam source which is designed to irradiate the liquid layer and / or the applied agent with electron radiation at least until it is partially cured.

Furthermore, the curing station preferably has a drying station which is designed to receive the workpiece until the layer has at least partially cured and, in particular, to provide a predetermined drying temperature by means of a heating source, to which the workpiece with the layer can be exposed.

The device preferably also has a control means which is designed to control the device in accordance with the method steps. This can be, for example, an electronically controlled control unit, in particular a control unit, which is designed to transmit electronic control signals to the further elements of the device and preferably to receive signals from the further elements of the device. For example, feedback about the currently dispensed quantity of droplets or their speed and further information relating to the method can be transmitted to the control means, whereby the control means receives information about the current implementation of the method and can provide appropriately adapted control signals.

The device preferably furthermore has a reaction area which is designed to enable evaporation and / or a chemical reaction, the reaction area being in particular designed as a area through which the transport device transports the workpiece, and its expansion and the transport speed in such a way to one another are coordinated so that evaporation and / or a reaction are at least partially made possible. For example, it can be a chamber through which the workpiece, which can also be in the form of a web, is transported.

The device preferably also has a protective gas chamber which is designed to at least have the workpiece and / or the layer and / or the agent of a section during the transport with a protective gas, in particular an inert gas, preferably nitrogen. This makes it possible to create an atmosphere which does not influence a chemical reaction of the layer with the agent or a polymerization by electromagnetic radiation.

The device preferably also has an application device which is designed to apply the liquid layer to the workpiece. This application device has, in particular, a rolling mill which is designed to coat the workpiece with a liquid layer. Alternatively or additionally, a spray head can also be provided which applies the liquid layer to the surface of the workpiece by means of nozzles.

The device preferably also has a structuring element which is designed to introduce a structure into the liquid layer. This can preferably be an analog embossing roller or an embossing plate, on which a structure is provided by means of elevations, which can be transferred to the liquid layer by pressing it into it. Alternatively or additionally, the structuring element has at least one digital print head, which is designed to apply structuring droplets to the liquid layer. The digital print head is preferably able to adapt the pulse and / or volume and / or speed of the structuring droplets in such a way that the structuring droplets achieve a structuring effect when they hit the liquid layer, in particular by displacing the liquid layer.

The device preferably also has an application device for applying a decorative image, with at least one digital print head which is designed to apply color to the surface of the layer and / or the workpiece. It is thus possible to provide the surface of the workpiece and / or the layer with a decorative image.

The transport device preferably has a transport belt, the elements of the device described above being successively in the main transport direction are arranged. In this case, a processing sequence of the method steps can be specified in particular via the arrangement sequence.

The dispensing device preferably has at least one digital digital print head which is designed to dispense the agent. The digital print head is preferably designed such that it can deliver the agent either in the form of fine droplets or droplets onto the surface of the liquid layer. It is also preferably designed to meter in particular the volume, speed and / or impulse of the fine pots and / or droplets in accordance with a specification, for example from the control means.

The reaction area preferably has special boundary conditions which are necessary for triggering evaporation and / or a chemical reaction.

The reaction area preferably extends at least over part of the protective gas chamber. In this way, it is advantageously achieved that the reaction takes place at least partially under protective gas, so that the influence of undesired chemical components, in particular the ambient air, is minimized.

The device elements described here are not to be seen as limiting the subject matter of the device according to the invention. Rather, further devices can be obtained by swapping, multiplying or omitting individual elements. For example, after the first coating and matting with a liquid layer, a further coating with a liquid layer can also be carried out, which is also matted in order to achieve special optical effects.

Figur 1

ein Werkstück das mit einer flüssigen Schicht beschichtet ist und auf das ein Mittel in Form von Tröpfchen aufgetragen wird;

Figur 2

das Werkstück in einer Schutzgaskammer, in der es mittels einer Lampe mit elektromagnetischer Strahlung bestrahlt wird;

Figur 3

das Werkstück mit unterschiedlichen Mattierungsgraden der aufgetragenen Schicht;

Figur 4

die Einwirkung der elektromagnetischen Strahlung auf die flüssige Schicht und auf das aufgetragene Mittel;

Figur 5

eine weitere Ausführungsform, in der das Mittel lediglich auf die Oberfläche der flüssigen Schicht aufgetragen wurde, ohne diese in ihrer Struktur zu verändern;

Figur 6

ein alternatives Werkstück als Bahnware

Figur 7

ein Ablaufdiagramm einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens;

Figur 8

einen schematischen Aufbau einer bevorzugten Ausführungsform einer erfindungsgemäßen Vorrichtung.

Furthermore, specific exemplary embodiments of the invention are described with the aid of the accompanying drawings. Show it:

Figure 1

a workpiece which is coated with a liquid layer and onto which an agent in the form of droplets is applied;

Figure 2

the workpiece in a protective gas chamber in which it is irradiated by means of a lamp with electromagnetic radiation;

Figure 3

the workpiece with different degrees of matting of the applied layer;

Figure 4

the effect of electromagnetic radiation on the liquid layer and on the applied agent;

Figure 5

a further embodiment in which the agent has only been applied to the surface of the liquid layer without changing its structure;

Figure 6

an alternative workpiece as a web product

Figure 7

a flow diagram of a preferred embodiment of the method according to the invention;

Figure 8

a schematic structure of a preferred embodiment of a device according to the invention.

In Figure 1 is a workpiece 1, shown with a liquid layer 2 applied thereon and an agent which has been sprayed onto the layer 2 in the form of droplets 3 from digital print heads 4 arranged above it. The workpiece 1 is moved in a transport direction under the print heads 4 from right to left, so that the print heads 4 can apply the droplets 3 to the liquid layer 2 in different places.

The device is designed to at least partially absorb electromagnetic radiation. It can thus be achieved that parts of the surface of the liquid layer 2 which are covered with the agent can be at least partially shielded from the direct influence of electromagnetic radiation.

It can be seen that the droplets 3 produced depressions when they hit the liquid layer 2, the viscosity of the liquid layer 2 being such that these depressions do not immediately recede. Thus, by applying the droplets 3, the liquid layer 2 can be structured at least over a certain period of less than 5 minutes, preferably less than 3 minutes, which can be permanently solidified by subsequent hardening.

In Figure 2 is this workpiece 1 with the liquid layer 2 in a protective gas chamber 24, which predominantly has a nitrogen atmosphere in the interior 5, in order to keep oxygen atoms or oxygen molecules away from the surface of the layer 2 in order to make undesired chemical reactions with oxygen in the air more difficult.

The surface of the layer 2 here has a structure which is defined by the droplets 3, as in FIG Figure 1 represented, was generated. The droplets 3 are still in the depressions.

Furthermore, a radiation source 6 for electromagnetic radiation 6a is provided, under which the workpiece 1 with the liquid layer 2 structured through the depressions is moved. The radiation source 6 is designed such that it emits the electromagnetic radiation 6a onto the surface of the liquid layer 2. The electromagnetic radiation 6a has, for example, a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm.

Instead of nitrogen, another inert gas atmosphere can also be formed in the interior 5 of the protective gas chamber 24, which is suitable for keeping oxygen atoms and / or molecules, in particular, away from the surface of the layer 2.

The protective gas chamber 24 can be designed as a closed space or as an area through which a workpiece 1 is moved. This is particularly advantageous for web-shaped workpieces 1,
Figure 3 shows the liquid layer 2 on the workpiece 1 after irradiation with electromagnetic radiation 6a from the radiation source 6. The surface of the liquid layer 2 is polymerized more or less strongly at various points.

At points 7, the electromagnetic radiation 6a could hit the surface of layer 2 unhindered, as a result of which a stronger polymerization took place here. At this point, the surface has become rougher, at least in the micro or nano range, since the molecules of the liquid layer 2 near the surface have become more cross-linked due to the electromagnetic radiation 6a. Therefore light that falls on these points 7 is now reflected in several directions, ie diffusely, whereby a higher degree of mattness of these points 7 is achieved.

In contrast, the electromagnetic radiation 6a could not reach the locations 8 of the surface of the liquid layer 2 directly, since these, as in FIGS Figures 1 and 2 shown with which means in the form of droplets 3 were covered. The agent is no longer present on the surface of the liquid layer 2, since it has evaporated, for example.

However, the agent at least partially absorbed the electromagnetic radiation at the lower points 8, so that polymerization of the surface of the liquid layer 2 could not take place here to the same extent as at the points 7. As a result, the lower points 8 are therefore less rough , at least in the micro or nano range, as a result of which a reflection of incident light is scattered less strongly. The digits 8 therefore appear more shiny than the digits 7.

Figure 4 shows in the lower representation a section, which is marked in the upper representation by the two vertical dashed lines, from the layer 2 on the workpiece 1 and the agent sprayed thereon in the form of droplets 3 which emit the electromagnetic radiation 6a at the locations of the At least partially absorb droplets 3.

It can be seen that at locations that are not covered with the droplets 3, the electromagnetic radiation 6 a can strike the surface of the liquid layer 2 unhindered. This is illustrated by the length of the arrows of the electromagnetic radiation 6a, which describe the intensity with which the surface of the liquid layer 2 is irradiated.

In contrast, the intensity of the electromagnetic radiation 6a on the surface of the liquid layer 2 is significantly lower at locations covered with droplets 3, as can be seen from the comparatively short arrows of the electromagnetic radiation 6a below the droplets 3.

Figure 5 shows a further embodiment, in which the agent was only applied to the surface of the liquid layer without changing its structure.

The agent is applied here in the form of fine droplets 3a which have been applied to the liquid layer in such a way that they do not sink into the surface of the liquid layer 2 or do not displace it and introduce depressions. This can be achieved, for example, by adapting the fine droplets 3a in their volume and / or in their impact speed in such a way that the surface of the liquid layer is not changed by the latter.

In this case, an impulse of the fine droplets 3a can be set such that it is not sufficient to break through the surface tension of the liquid layer 2, as a result of which the fine droplets 3a do not sink into the liquid layer 2 and / or that it is not sufficient to to overcome the viscosity forces of the liquid layer 2, as a result of which no depressions are introduced into the liquid layer 2 due to the fine droplets 3a.

It can also be seen that the fine droplets 3a are dimensioned such that they form a fine haze on the surface of the liquid layer, at least on partial surfaces thereof.

In this way it is possible to apply electromagnetic radiation 6a to the surface of the liquid layer 2 at different locations to different extents, since it penetrates the surface of the liquid layer to a lesser extent at locations which have the agent. This is comparable to Figure 4 , represented by the different arrow lengths of the electromagnetic radiation 6a. Thus, the surface at locations 7 that are not covered with the fine droplets 3a is irradiated with a higher intensity than locations 8 that were at least partially shielded from the electromagnetic radiation 6a by the means in the form of fine droplets 3a or a veil thereof .

Figure 6 shows an alternative workpiece 1 as a web, which is unwound from a roll 9 and is also coated with a liquid layer 2. The workpiece 1 moves continuously to the right, where further processing steps described above (not shown) follow.

In this embodiment, the liquid layer 2 is applied after rolling off the roll 9 by means of a rolling mill 10. The matting process can thus not only be applied to individual flat workpieces, such as plates, for example made of wood, plastic or metal, but also to sheet-like workpieces 1,
Figure 7 shows a flow chart of a preferred embodiment of the method according to the invention.

In a first processing step, a liquid layer S20 is applied to the surface of a workpiece. This can, for example, in the in Figure 6 shown way.

Structuring S22 of the workpiece coated in this way then takes place, so that the liquid layer is provided with a structure after this step has been carried out. The structuring of the liquid layer can take place, for example, using an analog structuring method, in particular using a mechanical one Embossing the surface of the liquid layer, for example by rolling an embossing roller on the surface of the liquid layer.

As an alternative or in addition, the structuring of the liquid layer can also take place digitally, droplets, for example being applied to the surface of the liquid layer with digital print heads, which dropping into and / or displacing the latter. The droplets are advantageously made of the same material as the liquid layer in order to achieve only a structuring effect. In another embodiment, the droplets can be made of a different material than the liquid layer, as a result of which, for example, a chemical reaction between the liquid layer and droplets can be achieved, in particular by later irradiation with electromagnetic radiation and / or electron radiation and / or an increase in temperature. The chemical reaction is designed in such a way that its reaction product has a structuring effect on the surface of the liquid layer, as a result of which it is changed optically and / or haptically.

If there is a decorative image on the workpiece, which was covered by the application S20 of the liquid, in particular partially transparent layer, the structuring of the surface ensures that the structure is synchronous with the image visible through the liquid layer.

The workpiece prepared in this way is then fed to a digital printing station, for example via a continuous belt conveyor (S10).

In a further step S12, the digital printing station enables an agent which is designed to at least partially absorb electromagnetic radiation to be applied to the surface of the liquid layer.

The agent S12 can be applied in the form of droplets which are adjusted, for example, in terms of speed and volume, in such a way that they can overcome the surface tension and / or the viscosity forces of the liquid layer in order to structure it. Alternatively or additionally, the application S12 of the agent in the form of fine droplets, which are dimensioned such that they do not change the surface of the liquid layer, but only cover it at least on partial surfaces.

This is followed by the irradiation S14 of the surface of the liquid layer with high-energy electromagnetic radiation, as in Figures 2 , 4th and 5 shown, partial areas of the liquid layer, which are covered with the agent, experience a radiation influence with reduced intensity compared to partial areas, which are not covered with the agent and instead are directly exposed to the radiation.

Irradiation S14 of the surface of the liquid layer leads to its polymerisation to a certain depth of penetration, for example 0.1 μm, preferably less than 0.01 μm, where, as in Figure 3 shown, where the radiation was directly exposed to more. After completion of the irradiation S14, these spots are therefore more matt than the spots that were covered with the agent.

The applied agent is then evaporated in a further step S18. This can be done, for example, solely by heating the agent, for example with an IR lamp, the agent advantageously having a lower evaporation temperature than the liquid layer.

If, on the other hand, the agent has the property that it evaporates after a certain time, the evaporation S18 can only consist in waiting until the agent has evaporated. This can be done, for example, in that the workpiece is transported on a belt conveyor before the next method step is carried out, the length, transport speed and ambient temperature of this belt conveyor being designed such that evaporation S18 is made possible during the transport.

Then, in a further step, the liquid and now at least partially matted layer S16 is hardened.

For this purpose, the workpiece, in particular the liquid layer, can be irradiated again with electromagnetic radiation which comes from the same radiation source as was used in step S14. Alternatively, other radiation sources can also be provided, or other types of curing, such as active or passive air drying, or irradiation with electron beams can take place.

Figure 8 shows a schematic structure of a preferred embodiment of a device 18 according to the invention.

A transport device 20 is shown, which is designed as a belt transport, on which a workpiece 1 is transported in the transport direction 28. A liquid layer 2 is applied to the top of the workpiece 1.

The workpiece 1 is transported into a protective gas chamber 24 in the transport direction 28 in the further course of the transport. This has a protective gas atmosphere, in particular an inert gas atmosphere, for example a nitrogen atmosphere, in its interior 5, as a result of which oxygen in particular can be kept away from the liquid layer 2, as a result of which undesired chemical reactions are avoided.

Furthermore, digital printheads 4 are provided in the interior 5 of the protective gas chamber 24 and are designed to apply a means which is designed to at least partially absorb electromagnetic radiation to the liquid layer 2. In the illustration shown, this is done by applying droplets 3, the digital print heads 4 being designed to control the droplet dispensing, in particular with regard to the droplet speed, volume and pulse.

Alternatively or additionally, the agent can also be applied from the digital print heads 4 in the form of fine droplets 3a, which are distributed as evenly as possible on the surface of the liquid layer 2 and in particular join together to form partial areas.

Downstream of the digital print heads 4 is a radiation source 6, which is designed to emit electromagnetic radiation 6a with a wavelength of in particular less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm, onto the surface of the liquid layer 2 to achieve the matting described above.

Furthermore, a control means (not shown) is provided, which is designed to control the device 18 and its elements in order to carry out the method according to the invention.

The embodiments shown here do not limit the subject matter of the invention. Rather, further embodiments are conceivable. So it can be in Figure 7 described methods also have further method steps, or individual method steps can be interchanged or omitted. In the following, further aspects of the invention are to be concretized on the basis of further specific exemplary embodiments.

Example 1:

An HDF board is coated with a white printing background. The plate coated in this way is fed to a digital printer (in an alternative embodiment also a rotary printing machine with several colors) and printed decoratively with a wood decor, for example. In an alternative embodiment, an intermediate layer of lacquer or primer, ideally transparent, can be applied to this decorative layer printed in this way. Then a liquid layer 2 is applied with a layer thickness of 50-80 microns. This layer can be applied in a roller application machine or, in an alternative embodiment, also in a spraying machine. The layer consists of a UV-curing acrylate mixture. The HDF plate coated in this way is fed to a further printing station, in which droplets 3 are sprayed onto parts of the surface from digital print heads. In the embodiment shown here, these droplets consist of an aqueous mixture, including in particular the following components

In an alternative embodiment, the droplets can also consist of a solvent-based or an acrylate-based liquid.

The droplets at the points where they hit change the surface of the still liquid layer in such a way that they are affected by a high speed of 4-6 m / sec. displace the still liquid layer 2.

The workpiece with the liquid layer 2 modified in this way is then fed to a radiation source 6 which emits electromagnetic radiation 6a with a wavelength of <250 nm onto the surface. This electromagnetic radiation is at least partially absorbed by the droplets 3 and strikes the layer 2 lying underneath. This layer 2 begins to polymerize in its surface and thereby fold (see reference number 7) Fig. 3 . In the lower-lying places, in which the droplets 3 have at least partially absorbed the electromagnetic radiation, there is less polymerization and thus less folding at the places 8 in Fig. 3 .

This results in the desired product with different degrees of gloss or mattness in the pores or outside the pores. The workpiece is then fed to yet another UV radiation source with a wavelength> 300 nm in order to completely harden the underlying, still liquid layer 2, in particular the acrylate layer.

• Zuführen S10 des Werkstückes 1, das mit einer flüssigen Schicht 2 beschichtet ist, zu einer digitalen Druckstation;
• Aufbringen S12 eines Mittels, das dazu ausgebildet ist, elektromagnetische Strahlung zumindest teilweise zu absorbieren, zumindest auf eine Teilfläche der Oberfläche der flüssigen Schicht 2, oder welches in Kontakt mit der Oberfläche ein Reaktionsprodukt entstehen lässt, das derart beschaffen ist, dass es elektromagnetische Strahlung zumindest teilweise zu absorbieren vermag;
• Bestrahlen S14 der Oberfläche der flüssigen Schicht 2 und des Mittels mit elektromagnetischer Strahlung mit einer Wellenlänge von weniger als 300 nm, bevorzugt weniger als 250 nm, besonders bevorzugt weniger als 200 nm.

According to a first aspect of the invention, a method for producing a decorative surface on a workpiece 1 is provided with the following steps:

• Feeding S10 of the workpiece 1, which is coated with a liquid layer 2, to a digital printing station;
• Application S12 of an agent which is designed to at least partially absorb electromagnetic radiation, at least to a partial surface of the surface of the liquid layer 2, or which, in contact with the surface, gives rise to a reaction product which is such that it at least contains electromagnetic radiation able to partially absorb;
• Irradiate S14 of the surface of the liquid layer 2 and of the agent with electromagnetic radiation with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm.

• das Mittel auf die flüssige Schicht 2, insbesondere mittels eines Digitaldruckkopfes 4 oder eines Digital-Düsenbalkens, in Form von feinen Tröpfchen 3a aufgesprüht und/oder in Form von Tröpfchen 3 aufgebracht wird, wobei die feinen Tröpfchen 3a insbesondere ein Volumen von 0,1 pl bis 1 pl, vorzugsweise von 0,3 pl bis 0,8 pl, besonders bevorzugt von 0,5 bis 0,6 pl aufweisen, und/oder die Tröpfchen 3 insbesondere ein Volumen von 1 pl bis 80 pl, vorzugsweise von 3 pl bis 12 pl, besonders bevorzugt von 5 pl bis 10 pl aufweisen, und/oder
• das Mittel in seinen chemischen und/oder physikalischen Eigenschaften dazu ausgebildet ist, um mindestens 10%, vorzugsweise mindestens 30%, besonders bevorzugt mindestens 50% einfallender elektromagnetischer Strahlung zu absorbieren.

According to a second aspect of the invention, a method according to the first aspect is provided, wherein

• the agent is sprayed onto the liquid layer 2, in particular by means of a digital print head 4 or a digital nozzle bar, in the form of fine droplets 3a and / or in the form of droplets 3, the fine droplets 3a in particular having a volume of 0.1 pl up to 1 pl, preferably from 0.3 pl to 0.8 pl, particularly preferably from 0.5 to 0.6 pl, and / or the droplets 3 in particular have a volume from 1 pl to 80 pl, preferably from 3 pl to 12 pl, particularly preferably from 5 pl to 10 pl, and / or
• the chemical and / or physical properties of the agent are designed to absorb at least 10%, preferably at least 30%, particularly preferably at least 50% of incident electromagnetic radiation.

According to a third aspect of the invention, a method according to the second aspect is provided, wherein
the droplets 3 and / or the fine droplets 3a are released in such a way that when they hit the surface of the liquid layer 2 they at least partially penetrate into it and / or come to rest on it and / or displace it and introduce depressions, the Droplets 3 and / or the fine droplets 3a can be adjusted in particular in volume and / or speed in order to influence the depth of penetration and the displacement.

According to a fourth aspect of the invention, a method according to one of the three aforementioned aspects is provided, wherein
forming a microstructure or a nanostructure by irradiating S14 the surface of the liquid layer 2 with the electromagnetic radiation in the surface of the uppermost partial surface of the liquid layer 2 is carried out, which in the later use of the workpiece scatters 1 light reflection and thus gives an optically more matte impression.

• die flüssige Schicht 2 aus einem polymerisationsfähigen Acrylatgemisch besteht, und/oder
• das aufgebrachte Mittel aus einem polymerisationsfähigen Acrylatgemisch und/oder aus einer lösemittelhaltigen Flüssigkeit oder aus einem wässrigen Gemisch, insbesondere mit einem Wasseranteil von mehr als 30 %, bevorzugt mehr als 50 %, besteht.

According to a fifth aspect of the invention, a method according to one of the four aforementioned aspects is provided, wherein

• the liquid layer 2 consists of a polymerizable acrylate mixture, and / or
• the applied agent consists of a polymerizable acrylate mixture and / or of a solvent-containing liquid or of an aqueous mixture, in particular with a water content of more than 30%, preferably more than 50%.

According to a sixth aspect of the invention, a method according to one of the five aforementioned aspects is provided, wherein
in a further step curing S16 of layer 2, preferably by irradiation with electromagnetic radiation, with a wavelength preferably greater than 250 nm, particularly preferably greater than 300 nm, and / or by irradiation with electron radiation and / or by active and / or passive drying and / or by reaction hardening, for example using a two-component system.

• einen Stoff aus der Gruppe der gehinderte Amine in einer Konzentration von 0 - 20%
• einen Stoff aus der Gruppe der N,N'-Diphenyleoxamide in einer Konzentration von 0 - 20% und/oder

das aufgebrachte Mittel neben einem Alkohol und/oder einem Glykol mit einem gesamten Anteil (Alkohol und/oder Glykol) von 10 - 99 % mindestens einen der folgenden Inhaltsstoffe in der genannten Konzentration (Vol-%) aufweist:

• einen Stoff aus der Gruppe der gehinderte Amine in einer Konzentration von 0 - 20%
• einen Stoff aus der Gruppe der N,N'-Diphenyleoxamide in einer Konzentration von 0 - 20%, und/oder

das aufgebrachte Mittel neben einem Polymer-Anteil von 10-99% mindestens einen der folgenden Inhaltsstoffe in der genannten Konzentration (Vol-%) aufweist:

• einen Stoff aus der Gruppe der Benzophenone in einer Konzentration von 0 - 15%
• einen Stoff aus der Gruppe der Benzotrialzole in einer Konzentration von 0 - 15%.

According to a seventh aspect of the invention, a method according to one of the six aforementioned aspects is provided, wherein
the applied agent consists only of water, or in addition to water with a total share of 10 - 99% has at least one of the following ingredients in the stated concentration (% by volume):

• a substance from the group of hindered amines in a concentration of 0-20%
• a substance from the group of N, N'-diphenyleoxamides in a concentration of 0-20% and / or

the applied agent contains, in addition to an alcohol and / or a glycol with a total proportion (alcohol and / or glycol) of 10 - 99%, at least one of the following ingredients in the stated concentration (% by volume):

• a substance from the group of hindered amines in a concentration of 0-20%
• a substance from the group of N, N'-diphenyleoxamides in a concentration of 0-20%, and / or

the applied agent has, in addition to a polymer content of 10-99%, at least one of the following ingredients in the stated concentration (% by volume):

• a substance from the group of benzophenones in a concentration of 0 - 15%
• a substance from the group of benzotrialzenes in a concentration of 0 - 15%.

• das aufgebrachte Mittel so beschaffen ist, dass es, insbesondere nach dem Bestrahlen S14, innerhalb von weniger als 3 Minuten, bevorzugt innerhalb von weniger als 1 Minute, besonders bevorzugt innerhalb weniger als eine halben Minute, verdampft, und/oder
• ein weiterer Schritt S18 vorgesehen ist, in dem die Verdampfung des Mittels innerhalb von weniger als 3 Minuten, bevorzugt innerhalb von weniger als 1 Minute, besonders bevorzugt innerhalb weniger als eine halben Minute, durchgeführt wird.

According to an eighth aspect of the invention, a method according to one of the seven aforementioned aspects is provided, wherein

• the applied agent is such that it evaporates, in particular after the irradiation S14, within less than 3 minutes, preferably within less than 1 minute, particularly preferably within less than half a minute, and / or
• a further step S18 is provided in which the evaporation of the agent is carried out within less than 3 minutes, preferably within less than 1 minute, particularly preferably within less than half a minute.

• das Mittel beim Auftreffen auf die Oberfläche der Schicht 2 mit dieser eine chemische Reaktion dergestalt eingeht, dass an den Stellen eine optische und/oder haptische Änderung der Oberfläche erfolgt, und/oder
• ein chemischer Reaktionsschritt vorgesehen ist, der so ausgestaltet ist, dass der chemischen Reaktion zwischen dem aufgebrachten Mittel und der Schicht 2 genügend Zeit gegeben wird, dass die chemische Reaktion zumindest teilweise abläuft.

According to a ninth aspect of the invention, a method according to one of the eight aforementioned aspects is provided, wherein

• when the agent strikes the surface of the layer 2, a chemical reaction occurs in such a way that there is an optical and / or haptic change in the surface at the points, and / or
• a chemical reaction step is provided which is designed such that the chemical reaction between the applied agent and the layer 2 is given sufficient time for the chemical reaction to take place at least partially.

According to a tenth aspect of the invention, a method according to one of the nine aforementioned aspects is provided, wherein
the applied agent, when it strikes the layer 2, undergoes a chemical reaction in such a way that the reaction product at this point, due to the irradiation S14, achieves no or less micro- or nanostructure formation than on the surfaces on which no agent has been applied to the surface has been.

• in einem weiteren Schritt S20 die flüssige Schicht 2 auf eine Oberfläche des Werkstücks 1 aufgetragen wird, und/oder
• in einem weiteren insbesondere zeitgleich zu Schritt S12 ausgeführten Schritt S22 die Schicht 2 mittels eines analogen Strukturierungsverfahrens, insbesondere mit einer Prägewalze strukturiert wird, und/oder mittels analoger oder digitaler Verfahren mittels Aufbringen weiterer Strukturierungströpfchen verdrängt wird, wobei Vertiefungen in die Schicht 2 eingebracht werden, und/oder
• in einem weiteren Schritt, insbesondere mittels Digitaldruck, ein Dekorbild auf die Oberfläche des Werkstücks 1 und/oder auf die Schicht 2, die zumindest teilweise ausgehärtet ist, oder welche eine durch Polymerisation verfestigte Oberfläche aufweist, aufgebracht wird.

According to an eleventh aspect of the invention, a method according to one of the ten aforementioned aspects is provided, wherein

• in a further step S20, the liquid layer 2 is applied to a surface of the workpiece 1, and / or
• in a further step S22, which is carried out at the same time as step S12, layer 2 is structured by means of an analog structuring method, in particular with an embossing roller, and / or is displaced by means of analog or digital methods by applying further structuring droplets, recesses being introduced into layer 2, and or
• in a further step, in particular by means of digital printing, a decorative image is applied to the surface of the workpiece 1 and / or to the layer 2, which is at least partially hardened, or which has a surface hardened by polymerization.

• eine Transportvorrichtung 20 mit einer Transportrichtung 28, wobei die Transportvorrichtung 20 dazu ausgebildet ist, ein Werkstück 1, das mit einer flüssigen Schicht 2 beschichtet ist, zu weiteren Elementen der Vorrichtung zu transportieren,
• eine Abgabevorrichtung, die dazu ausgebildet ist, ein Mittel zumindest auf eine Teilfläche der Oberfläche der flüssigen Schicht 2 aufzubringen;
• eine Strahlenquelle 6, die dazu ausgebildet ist, die Oberfläche der flüssigen Schicht 2 mit elektromagnetischer Strahlung 6a mit einer Wellenlänge von weniger als 300 nm, vorzugsweise weniger als 250 nm, besonders bevorzugt weniger als 200 nm, zu bestrahlen.

According to a twelfth aspect of the invention, a device 18 for carrying out the method according to one of the aforementioned eleven aspects is provided, the device 18 comprising the following elements:

• a transport device 20 with a transport direction 28, the transport device 20 being designed to transport a workpiece 1, which is coated with a liquid layer 2, to further elements of the device,
• a dispensing device configured to apply an agent to at least a partial surface of the surface of the liquid layer 2;
• a radiation source 6, which is designed to irradiate the surface of the liquid layer 2 with electromagnetic radiation 6a with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm.

• eine Strahlenquelle, die dazu ausgebildet ist, die flüssige Schicht 2 und/oder das aufgebrachte Mittel mit elektromagnetischer Strahlung veränderbarer Wellenlänge, insbesondere mit IR-Strahlung, und/oder Elektronenstrahlung veränderbarer Wellenlänge zumindest bis zu ihrer teilweisen Aushärtung zu bestrahlen, wobei die Strahlenquelle mit der Strahlenquelle 6 identisch ist und/oder separat ausgebildet ist, und/oder
• eine Fluidquelle, die dazu ausgebildet ist, die Schicht 2, insbesondere mit Luft zu umströmen, wobei das Fluid insbesondere in den Parametern Strömungsgeschwindigkeit und/oder Temperatur und/oder Feuchte beeinflusst werden kann, und/oder
• eine Elektronenstrahlquelle, die dazu ausgebildet ist, die flüssige Schicht 2 und/oder das aufgebrachte Mittel mit Elektronenstrahlung zumindest bis zu ihrer teilweisen Aushärtung zu bestrahlen, und/oder
• eine Trocknungsstation, die dazu ausgebildet ist, das Werkstück 1 bis zum zumindest teilweisen Aushärten der Schicht 2 aufzunehmen und insbesondere mittels einer Heizquelle eine vorbestimmte Trocknungstemperatur bereitzustellen, der das Werkstück 1 mit der Schicht 2 ausgesetzt werden kann.

According to a thirteenth aspect of the invention, a device 18 according to the twelfth aspect is provided, the device 18 having a curing station which has:

• a radiation source which is designed to irradiate the liquid layer 2 and / or the applied agent with electromagnetic radiation of variable wavelength, in particular with IR radiation, and / or electron beam radiation with variable wavelength at least until its partial curing, the radiation source with the Radiation source 6 is identical and / or is formed separately, and / or
• a fluid source which is designed to flow around the layer 2, in particular with air, the fluid being able to be influenced in particular in the parameters of flow rate and / or temperature and / or moisture, and / or
• an electron beam source, which is designed to irradiate the liquid layer 2 and / or the applied agent with electron radiation at least until its partial curing, and / or
• a drying station which is designed to receive the workpiece 1 until the layer 2 has at least partially hardened and, in particular, to provide a predetermined drying temperature by means of a heating source, to which the workpiece 1 with the layer 2 can be exposed.

• ein Steuermittel, das dazu ausgebildet ist, die Vorrichtung entsprechend der Verfahrensschritte zu steuern, und/oder
• einen Reaktionsbereich, der dazu ausgebildet ist, ein Verdampfen und/oder eine chemische Reaktion zu ermöglichen, wobei der Reaktionsbereich insbesondere als Bereich ausgebildet ist, durch den die Transportvorrichtung das Werkstück 1 transportiert, und dessen Ausdehnung und die Transportgeschwindigkeit so aufeinander abgestimmt sind, dass ein Verdampfen und/oder eine Reaktion zumindest teilweise ermöglicht werden, und/oder
• eine Schutzgaskammer 24, die dazu ausgebildet ist, das Werkstück 1 und/oder die Schicht 2 und/oder das Mittel zumindest auf einer Teilstrecke während des Transports mit einem Schutzgas, insbesondere einem Inertgas, vorzugsweise Stickstoff, zu umgeben, und/oder
• eine Auftragsvorrichtung 10, die dazu ausgebildet ist, die flüssige Schicht 2 auf das Werkstück 1 aufzutragen, und/oder
• ein Strukturierungselement, insbesondere eine Prägewalze und/oder einen Digitaldruckkopf, das dazu ausgebildet ist, in die flüssige Schicht 2 eine Struktur einzubringen, und/oder
• eine Auftragsvorrichtung zum Auftrag eines Dekorbildes, aufweisend mindestens einen Digitaldruckkopf der dazu ausgebildet ist, Farbe auf die Oberfläche der Schicht 2 und/oder des Werkstücks 1 aufzutragen.

According to a fourteenth aspect of the invention, a device 18 according to the twelfth or thirteenth aspect is provided, which further comprises the following elements:

• a control means which is designed to control the device in accordance with the method steps, and / or
• a reaction area which is designed to enable evaporation and / or a chemical reaction, the reaction area being designed in particular as a area through which the transport device transports the workpiece 1 and whose expansion and the transport speed are coordinated with one another such that a Evaporation and / or a reaction are made possible at least in part, and / or
• a protective gas chamber 24, which is designed to surround the workpiece 1 and / or the layer 2 and / or the agent at least on a partial route during the transport with a protective gas, in particular an inert gas, preferably nitrogen, and / or
• an application device 10, which is designed to apply the liquid layer 2 to the workpiece 1, and / or
• a structuring element, in particular an embossing roller and / or a digital print head, which is designed to introduce a structure into the liquid layer 2, and / or
• an application device for applying a decorative image, comprising at least one digital print head which is designed to apply color to the surface of the layer 2 and / or the workpiece 1.

• die Transportvorrichtung 20 ein Transportband aufweist und die Elemente nacheinander in der Transportrichtung 28 angeordnet sind, und/oder
• die Abgabevorrichtung mindestens einen digitalen Digitaldruckkopf 4 oder einen Digital-Düsenbalken aufweist, der zur Abgabe des Mittels ausgebildet ist, und/oder
• der Reaktionsbereich spezielle Randbedingungen aufweist, die zum Auslösen eines Verdampfens und/oder einer chemischen Reaktion nötig sind, und/oder
• der Reaktionsbereich sich zumindest über einen Teil der Schutzgaskammer 24 erstreckt.

According to a fifteenth aspect of the invention, a device 18 according to the twelfth, thirteenth or fourteenth aspect is provided, wherein

• the transport device 20 has a transport belt and the elements are arranged one after the other in the transport direction 28, and / or
• the dispensing device has at least one digital digital print head 4 or a digital nozzle bar, which is designed to dispense the agent, and / or
• the reaction area has special boundary conditions which are necessary to trigger evaporation and / or a chemical reaction, and / or
• the reaction area extends over at least part of the protective gas chamber 24.

Claims (17)

Method for producing a decorative surface on a workpiece (1) with the following steps: - Feeding (S10) the workpiece (1), which is coated with a liquid layer (2), to a digital printing station; Applying (S12) an agent which is designed to at least partially absorb electromagnetic radiation, at least to a partial surface of the surface of the liquid layer (2), or which in contact with the surface gives rise to a reaction product which is of such a nature, that it can at least partially absorb electromagnetic radiation; A method according to claim 1, characterized in that a further step is provided in which the surface of the liquid layer (2) and the agent is irradiated with electromagnetic radiation with a variable wavelength. A method according to claim 1 or 2, characterized in that
the agent is sprayed onto the liquid layer (2), in particular by means of a digital printhead (4) or a digital nozzle bar, in the form of fine droplets (3a) and / or applied in the form of droplets (3), the fine droplets ( 3a) in particular have a volume of 0.1 pl to 1 pl, preferably from 0.3 pl to 0.8 pl, particularly preferably from 0.5 to 0.6 pl, and / or the droplets (3) in particular have a volume from 1 pl to 80 pl, preferably from 3 pl to 12 pl, particularly preferably from 5 pl to 10 pl, and / or
the chemical and / or physical properties of the agent are designed to absorb at least 10%, preferably at least 30%, particularly preferably at least 50% of incident electromagnetic radiation. A method according to claim 3, characterized in that
the droplets (3) and / or the fine droplets (3a) are released in such a way that when they strike the surface of the liquid layer (2) they at least partially penetrate into it and / or come to rest on it and / or displace it and introduce depressions, the droplets (3) and / or the fine droplets (3a) being adjusted in particular in volume and / or speed in order to influence the depth of penetration and the displacement. Method according to one of the above claims, characterized in that
forming a microstructure or a nanostructure by irradiating (S14) the surface of the liquid layer (2) with the electromagnetic radiation in the surface of the uppermost partial surface of the liquid layer (2), which is used in the later use of the workpiece (1 ) Light reflection scatters, giving an optically more matte impression. Method according to one of the above claims, characterized in that
the liquid layer (2) consists of a polymerizable acrylate mixture, and / or
the applied agent consists of a polymerizable acrylate mixture and / or of a solvent-containing liquid or of an aqueous mixture, in particular with a water content of more than 30%, preferably more than 50%. Method according to one of the above claims, characterized in that
in a further step curing (S16) of the layer (2), preferably by irradiation with electromagnetic radiation, with a wavelength preferably greater than 250 nm, particularly preferably greater than 300 nm, and / or by irradiation with electron radiation and / or by active and / or passive drying and / or by reaction curing by means of, for example, a two-component system. Method according to one of the above claims, characterized in that a further step is provided: - Irradiate (S14) the surface of the liquid layer (2) and the agent with electromagnetic radiation with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm. Method according to one of the above claims, characterized in that
the applied agent consists only of water, or in addition to water with a total share of 10 - 99% has at least one of the following ingredients in the stated concentration (% by volume): - a substance from the group of hindered amines in a concentration of 0-20% - A substance from the group of N, N'-diphenyleoxamides in a concentration of 0-20% and / or the applied agent contains, in addition to an alcohol and / or a glycol with a total proportion (alcohol and / or glycol) of 10 - 99%, at least one of the following ingredients in the stated concentration (% by volume): - a substance from the group of hindered amines in a concentration of 0-20% - a substance from the group of N, N'-diphenyleoxamides in a concentration of 0-20%, and / or the applied agent has, in addition to a polymer content of 10-99%, at least one of the following ingredients in the stated concentration (% by volume): - a substance from the group of benzophenones in a concentration of 0 - 15% - a substance from the group of benzotrialzenes in a concentration of 0 - 15%. Method according to one of the above claims, characterized in that
the applied agent is such that it, in particular after the irradiation (S14), within less than 3 minutes, preferably within evaporated, and / or less than 1 minute, particularly preferably within less than half a minute
that a further step (S18) is provided in which the evaporation of the agent is carried out within less than 3 minutes, preferably within less than 1 minute, particularly preferably within less than half a minute. Method according to one of the above claims, characterized in that
when the agent strikes the surface of the layer (2), a chemical reaction occurs in such a way that there is an optical and / or haptic change in the surface at the points, and / or
that a chemical reaction step is provided which is designed in such a way that the chemical reaction between the applied agent and the layer (2) is given sufficient time for the chemical reaction to take place at least partially. Method according to one of the above claims, characterized in that
the applied agent, when it strikes the layer (2), undergoes a chemical reaction in such a way that the reaction product at this point does not achieve any or less micro- or nanostructure formation by irradiation (S14) than on the surfaces on which no agent was applied to the surface. Method according to one of the preceding claims, characterized in that
in a further step (S20) the liquid layer (2) is applied to a surface of the workpiece (1), and / or
in a further step (S22), which is carried out at the same time as step (S12), the layer (2) is structured using an analog structuring method, in particular with an embossing roller, and / or using analog or digital Method is displaced by applying further structuring droplets, depressions being introduced into the layer (2), and / or
in a further step, in particular by means of digital printing, a decorative image is applied to the surface of the workpiece (1) and / or to the layer (2) which has at least partially hardened or which has a surface hardened by polymerization. Device (18) for carrying out the method according to one of claims 1 to 13, comprising the following elements: a transport device (20) with a transport direction (28), the transport device (20) being designed to transport a workpiece (1) which is coated with a liquid layer (2) to further elements of the device, - A dispensing device which is designed to apply an agent to at least a partial surface of the surface of the liquid layer (2); - A curing station with a radiation source, which is designed to irradiate the liquid layer (2) and / or the applied means with electromagnetic radiation of variable wavelength, in particular with IR radiation, and / or electron beam radiation with variable wavelength at least until it is partially cured . The device (18) of claim 14, wherein
the device (18) has: - A radiation source (6) which is designed to irradiate the surface of the liquid layer (2) with electromagnetic radiation (6a) with a wavelength of less than 300 nm, preferably less than 250 nm, particularly preferably less than 200 nm , wherein the radiation source is identical to the radiation source (6) and / or is formed separately, and / or wherein the curing station has: - A fluid source which is designed to flow around the layer (2), in particular with air, the fluid being able to be influenced in particular in the parameters of flow velocity and / or temperature and / or moisture, and / or - An electron beam source, which is designed to irradiate the liquid layer (2) and / or the applied agent with electron radiation at least up to its partial curing, and / or - A drying station which is designed to receive the workpiece (1) until the layer (2) has at least partially hardened and, in particular, to provide a predetermined drying temperature by means of a heating source, to which the workpiece (1) with the layer (2) can be exposed . Apparatus (18) according to claim 14 or 15, further comprising the following elements: - A control means, which is designed to control the device according to the method steps, and / or - A reaction area which is designed to enable evaporation and / or a chemical reaction, the reaction area being in particular designed as a area through which the transport device transports the workpiece (1) and the expansion and the transport speed of which are coordinated with one another that vaporization and / or a reaction are made possible at least in part, and / or - A protective gas chamber (24) which is designed to surround the workpiece (1) and / or the layer (2) and / or the agent with a protective gas, in particular an inert gas, preferably nitrogen, at least on part of the route during transport , and or - An application device (10), which is designed to apply the liquid layer (2) to the workpiece (1), and / or - A structuring element, in particular an embossing roller and / or a digital print head, which is designed to introduce a structure into the liquid layer (2), and / or - An application device for applying a decorative image, comprising at least one digital print head which is designed to apply color to the surface of the layer (2) and / or the workpiece (1). Device (18) according to any one of claims 14 to 16, wherein
the transport device (20) has a transport belt and the elements are arranged one after the other in the transport direction (28), and / or
the dispensing device has at least one digital digital print head (4) or a digital nozzle bar, which is designed to dispense the agent, and / or
the reaction area has special boundary conditions which are necessary to trigger evaporation and / or a chemical reaction, and / or
the reaction area extends at least over part of the protective gas chamber (24).

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