Method and apparatus for producing a decorative workpiece and workpiece

Abstract

The inventions relates to a method for producing a decorative workpiece with a structured surface comprising the following steps: (B) applying a first liquid lacquer having a coarse structuring over the entire surface, wherein a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; (E) applying a second liquid, at least partially transparent lacquer for producing a fine structuring in some regions. Furthermore, an apparatus for performing the method and a workpiece produced by the method are claimed.

Claims

1. An apparatus for performing a method for producing a decorative workpiece with a structured surface comprising the following steps: applying a first liquid lacquer having a coarse structuring over the entire surface, wherein a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; and applying a second liquid, at least partially transparent, lacquer for producing a fine structuring in some regions, the apparatus comprising: a coating station for applying the first liquid lacquer with the coarse structuring to the workpiece over the entire surface, in which a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; and a station for applying the second liquid, at least partially transparent, lacquer for producing the fine structuring in some regions wherein the coating station comprises at least one printing roller, and the at least one printing roller is configured to unroll the first lacquer on a surface of the workpiece, and/or in that the apparatus comprises a device for feeding the workpiece to the coating station, and the device for feeding the workpiece to the coating station is configured to feed the workpiece to the coating station, and/or in that the apparatus comprises a station for at least partially curing the first lacquer, and the station for at least partially curing the first lacquer is configured to at least partial cure the applied first lacquer, and/or in that the apparatus comprises a station for curing the second lacquer, and the station for curing the second lacquer is configured to cure the second lacquer, wherein the difference in thickness in the region of fine structuring on the second lacquer layer is less than 50 μm, in particular less than 30 μm.

2. The apparatus according to claim 1, wherein the station for applying the second lacquer is configured to provide a gloss level in the regions of the fine structuring different by at least 10 gloss units as compared to the gloss level in the region of the coarse structuring.

3. The apparatus according to claim 1, wherein the apparatus comprises at least one digital print head, and the at least one digital print head is configured to apply the second lacquer.

4. The apparatus according to claim 1, wherein the apparatus is configured to provide the identical material for the first and the second lacquer.

5. The apparatus according to claim 1, wherein the coating station is configured to apply at least one intermediate layer between the workpiece and a layer of the first lacquer.

6. An apparatus for performing a method for producing a decorative workpiece with a structured surface comprising the following steps: applying a first liquid lacquer having a coarse structuring over the entire surface, wherein a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; and applying a second liquid, at least partially transparent, lacquer for producing a fine structuring in some regions, the apparatus comprising: a coating station for applying the first liquid lacquer with the coarse structuring to the workpiece over the entire surface, in which a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; and a station for applying the second liquid, at least partially transparent, lacquer for producing the fine structuring in some regions wherein the station for applying the second lacquer is configured to first apply a liquid lacquer to produce the second lacquer layer and then to spray lacquer droplets of the second lacquer layer into the still liquid material to produce a fine structuring.

7. The apparatus according to claim 6, wherein the station for applying the second lacquer is configured to provide the lacquer droplets made of the same material as the liquid layer.

8. The apparatus according to claim 6, wherein the station for applying the second lacquer comprises digital print heads, and the digital print heads are configured to apply a plurality of lacquer droplets onto the still liquid lacquer layer, wherein each lacquer droplet has a volume of less than 10 pL, and the velocity of each lacquer droplet upon impact on the still liquid lacquer layer is greater than 1 m/sec.

9. The apparatus according to claim 6, wherein the station for applying the second lacquer is configured to provide the lacquer droplets consisting of a material other than the liquid lacquer and undergo a chemical reaction with the liquid lacquer after impact, which changes the surface optically and/or haptically at the respective locations.

10. The apparatus according to claim 6, wherein the station for applying the second lacquer is configured to provide the lacquer droplets consisting of a different material than the liquid lacquer and after a physical reaction due to the impact on the liquid lacquer they volatilize within less than 5 minutes by evaporation.

11. An apparatus for performing a method for producing a decorative workpiece with a structured surface comprising the following steps: applying a first liquid lacquer having a coarse structuring over the entire surface, wherein a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; and applying a second liquid, at least partially transparent, lacquer for producing a fine structuring in some regions, the apparatus comprising: a coating station for applying the first liquid lacquer with the coarse structuring to the workpiece over the entire surface, in which a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; and a station for applying the second liquid, at least partially transparent, lacquer for producing the fine structuring in some regions, the apparatus further comprising: an application device configured to apply a decorative image to the workpiece and/or one of the applied lacquer layers, wherein the application device comprises in particular a multicolour digital printer, and/or a coating station and/or a device for feeding the workpiece to the coating station, and/or a station for at least partial curing of the first lacquer, and/or a station for curing the second lacquer, wherein the difference in thickness in the region of the fine structuring of the second lacquer layer is less than 50 μm, in particular less than 30 μm.

12. The apparatus according to claim 11, wherein the multicolour printer is configured to provide a further step (D) in which a decorative image is applied by multicolour printing before step (B) in which the first liquid lacquer having a coarse structuring over the entire surface is applied, wherein a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm, or after the applied first lacquer is at least partially cured.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) In the following the invention is explained in detail by way of the accompanying drawings. These show:

(2) FIG. 1 a schematic cross-sectional view of a plate-shaped workpiece produced by means of the method of the invention.

(3) FIG. 2 another schematic illustration of a plate-shaped workpiece produced by means of the method according to the invention with an indicated wood pore in plain view,

(4) FIG. 3 a surface of a printed workpiece, and

(5) FIG. 4 a view of a workpiece according to the invention having several layers.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

(6) FIG. 1 shows a plate-shaped workpiece 1.0 on which an optional first base layer 1.1 is provided on one surface. In addition, a decorative image, e.g. a wood reproduction or a tile image, is optionally printed on the workpiece 1.0 before the first base layer 1.1 is applied. In an alternative embodiment, a decorative image can also be printed on after application of the first base layer 1.1 or after application of a structured second base layer 1.2, for example using a four-colour digital printer. A second liquid base layer 1.2 is applied to the first base layer 1.1. This second base layer 1.2 has been structured with digitally sprayed droplets 1.3, so that the surface is no longer flat, but forms a structure and a first lacquer layer with a coarse structuring. Subsequently, a first lacquer layer 1.4 is applied, which has a first gloss level. A second lacquer layer 1.5 is then applied to the first lacquer layer 1.4 by digital print heads in order to create a fine structuring, wherein the second lacquer layer 1.5 only partially covers the surface of the first lacquer layer 1.4.

(7) The lacquer layers 1.4 and 1.5 are cured one after the other or together, for example by UV radiation. After curing, the second lacquer layer 1.5 has a different gloss level than the first lacquer layer.

(8) Instead of structuring the second base layer 1.2 with digitally sprayed droplets, it is also possible to structure a base layer using other methods, for example by applying it only to certain regions or using embossing matrices. It is also possible to apply the decorative image to a structured surface instead of a flat surface.

(9) FIG. 2 shows a plan view of the plate-shaped workpiece 1.0 of FIG. 1 and it can be seen that the decorative image comprises a wood pore 2.5 and grained wood regions 2.4. The different regions of the wood pore 2.5 and the grained wood regions 2.4 can also have a different gloss level due to the second lacquer layer 1.5, whereby the decorative regions of the image and the different gloss regions are preferably congruent as a result of the lacquer application.

(10) In a further embodiment, a carrier plate made of a wood material, or a plate made of another material with a thickness of at least 4 mm, preferably 8 to 16 mm and external dimensions of at least 200 mm width and at least 400 mm length is first coated with a UV-curing, white base lacquer, for example with an amount of about 20 g/qm. This white base lacquer is then cured under UV irradiation.

(11) The carrier plate is then fed to a digital printing device in which a printed image, for example a reproduction of small tiles as mosaics, a wood decor or another pattern, is applied with a four-color CMYK print.

(12) As an example of a printed image FIG. 3 shows a design with two mosaic tiles in different colors, which is printed on a plate-shaped workpiece 3.0, whereby bright mosaic tiles 3.1 and darker mosaic tiles 3.2 are envisaged. In an alternative embodiment a variety of other colors of tiles or mosaics with graphic representations can also be used.

(13) Then a thin base lacquer layer of 5-15 g/sqm of a UV-curing lacquer is applied to the carrier plate printed in this way and (partially) cured with UV light. In an alternative embodiment, this base lacquer layer can be completely omitted or replaced by a solvent lacquer or an aqueous acrylate lacquer, which is then physically dried.

(14) A further base lacquer layer 1.2 is then applied to the first base lacquer layer or alternatively directly to the printed image as a radiation-curing lacquer layer, preferably on an acrylate basis, in a layer thickness of 100-500 μm. The base lacquer layer can be applied by digital print heads or by printing rollers or other processes. Directly after the application of this second base lacquer layer 1.2, a further, transparent lacquer layer 1.3 is printed to the still liquid layer before curing, optionally by means of a digital printing template with digital print heads. When applying this lacquer layer 1.3 the droplet size can vary between 1 pL and 100 pL. The digital printing template used is the one that was also used to print the tile mosaic described above. This printing template is electronically modified beforehand so that only the interspaces 3.3 of the mosaic tiles 3.1 and 3.2 are printed. Then the radiation-curing base lacquer layer 1.2 is cured together with the lacquer layer 1.3 using a UV lamp. In an alternative embodiment, curing can also be performed using electron radiation.

(15) The result is a carrier plate printed with a tile mosaic in which the interspaces 3.3 are recessed by 10-60 μm as joints between the mosaic tiles 3.1 and 3.2.

(16) Subsequently, the gloss level of at least parts of the entire surface is adjusted to the desired value by at least partial application of a second lacquer layer 1.4 with subsequent drying, whereby the gloss level of the first lacquer layer 1.3 deviates from the gloss level of the second lacquer layer.

(17) In an alternative embodiment, the additional application of a third lacquer layer 1.5 can also be carried out before or after the second lacquer layer 1.4 has been cured, wherein the third lacquer layer 1.5 also consists of a large number of droplets with a size of 3-100 pL dispensed onto the surface. With this third lacquer layer, both the gloss level can be changed again in some regions and the surface structure depth of the uncured lacquer layer 1.4 can be influenced.

(18) The lacquer layers 1.4 and 1.5 can also be completely omitted if the gloss level is changed by applying the first lacquer layer 1.3 concomitantly with application of the second base lacquer layer 1.2 for structuring.

(19) The surface of the mosaic tiles 3.1 and 3.2 now has a value of 60 to 90 gloss units, for example, while the gloss level at the interspaces 3.3 is only 20 to 40 gloss units, for example.

(20) Optionally, the gloss level at the interspaces 3.3 can also be reduced by a further lacquer layer, which is subsequently printed into the recessed interspaces by a further digital printing device with a transparent, UV-curing lacquer. Then more than just two lacquer layers are applied to adjust the gloss level.

(21) For printing a rather matte lacquer layer, droplet sizes of 3-6 pL are used, which are cured within 0.5-2 sec after impact on the surface by means of UV LED radiation to such an extent that they can no longer flow. This creates a surface structure in these regions that no longer reflects the incident light in a straight line. The gloss level is thereby reduced to values of 30 gloss units and less.

(22) In the method of the invention, the second lacquer layer can have either a higher or lower gloss level than the first lacquer layer. The gloss level can be adjusted using the following methods, for example:

(23) Option 1:

(24) Matte regions through the first lacquer layer consist of previously (analog or digital) applied matte lacquer, for example with matting agents or by an excimer matting. Glossy regions of the second lacquer layer consist of lacquer applied by digital print heads, which lacquer is formed from a plurality of individual droplets, which results in a very smooth surface in certain regions and thus a high gloss level. The droplets have a size of at least 6 pL, and curing only takes place after a progression phase of at least 1 sec, preferably after more than 5 sec.

(25) Option 2:

(26) The glossy regions of the first lacquer layer consist of previously (analog or digital) applied glossy lacquer, matte regions of the second lacquer layer consist of digitally applied lacquer consisting of a plurality of smallest droplets having a droplet size of less than 8 pL, preferably less than 3 pL, which are at least partially cured within less than 3 seconds after application, preferably less than 1 sec after application.

(27) Both options preferably employ curing by a UV-LED lamp, which is arranged in the direction of throughput within less than 100 mm after the digital print heads, which apply the plurality of droplets to the surface.

(28) Matting agents, such as PE waxes or silicas, can be added to the lacquer to produce a matte lacquer layer. The proportion of matting agents in the lacquer can be between 2% to 6%, in particular 3% to 5% (weight percent).

(29) The different Examples of FIGS. 1 and 3 can be combined with one another as desired with regard to the application and structuring of a layer. The number of layers on the workpiece can also be freely selected, depending on the surface structure to be created with the method.

(30) In alternative embodiments of the method according to the invention, acrylate-containing, UV-curing lacquers used as the lacquers can be replaced by aqueous or solvent-based lacquers. In this case, the steps for UV drying by means of UV LED or UV arc lamp are replaced by physical drying by means of hot air or IR lamps or a combination of both.

(31) FIG. 4 shows another example of a coated plate-shaped workpiece 4.1.

(32) A workpiece 4.1, for example a board made of a wood-based material with a width of 200 to 2000 mm and a length between 500 and 3000 mm as well as a thickness between 8 mm and 18 mm is fed to a coating station. The workpiece 4.1 is already printed with a decor image, such as a wood reproduction, e.g. an oak decor.

(33) In the coating station, a plain intermediate lacquer layer 4.2, such as an adhesion base or primer, is optionally applied. A laser-engraved rubber roller is then used to apply a radiation-curing, transparent first lacquer layer 4.3 ranging from 100 to 200 g/m.sup.2 to the workpiece 4.1 whereby the engraving in the rubber roller creates the structure of a coarse wood pore on the surface. The height differences between the “pore valleys” and the elevations, i.e. the differences in thickness of the first lacquer layer 4.3, are between 150 μm and 300 μm (micrometers) and form a coarse structure. Subsequently, the applied lacquer is cured with a UV lamp. In an alternative embodiment, a decorative image 4.4 can be printed on the structured surface using a digital printer with 4-color printing after curing, if there was no image on the workpiece before the coating. In this case, the lacquer layer 4.3 can also be coloured, for example white.

(34) A further liquid lacquer layer 4.5 is applied to the now cured lacquer layer 4.3 with or without the coloured decorative printing layer 4.4 in a further coating station by means of a smooth rubber roller. The workpiece is then fed to a digital printing station 4.6, where a large number of droplets 4.7 is applied to the still liquid lacquer layer 4.5 based on a digital image template, which provide the still liquid lacquer layer 4.5 with a fine structuring. The digital image template is matched to the previously printed decorative image, e.g. rustic oak, in such a way that the visually recognisable image components, such as a knot hole or a black printed crack in the wood, correspond exactly spatially with the structure printed into the liquid pore. Thus the end user can also feel the optically printed knothole. At the same time the very deep and coarse structure from lacquer layer 4.3 lies above all, emphasising the rustic character of the oak reproduction.

(35) Finally, several aspects of the present invention are described.

(36) A first aspect of the invention is a method of manufacturing a decorative workpiece with a textured surface comprising the following steps: A feeding the workpiece to a coating station; B applying a first liquid lacquer having a coarse structuring over the entire surface, wherein a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; C at least partially curing the applied first lacquer; D applying a decorative image using multicolour printing before step B or after step C; E applying a second liquid, at least partially transparent lacquer for producing a fine structuring in certain regions; F curing of the second lacquer, wherein the difference in thickness in the region of the fine structuring of the second lacquer layer is less than 50 μm, in particular less than 30 μm.

(37) A second aspect of the method according to the first aspect is that the gloss level in the region of fine structuring differs by at least 10 gloss units as compared to the region of coarse structuring.

(38) A third aspect of the method according to the first or second aspect is that the application of the first lacquer is carried out with at least one printing roller that unrolls on a surface of the workpiece.

(39) A fourth aspect of the method according to one of the previous aspects is that the second lacquer is applied by at least one digital print head.

(40) A fifth aspect of the method according to one of the previous aspects is that the material for the first and second lacquer is identical.

(41) A sixth aspect of the method according to one of the previous aspects is that in order to produce the second lacquer layer, a liquid lacquer is first applied and then lacquer droplets of the second lacquer layer are sprayed into the still liquid material to produce a fine structuring.

(42) A seventh aspect of the method according to the sixth aspect is that the lacquer droplets consist of the same material as the liquid layer.

(43) An eighth aspect of the method according to the sixth or seventh aspect is that the application of a plurality of lacquer droplets into the still liquid lacquer layer is carried out by means of digital print heads, wherein each lacquer droplet has a volume of less than 10 pL, and the speed of each lacquer droplet when impacting the still liquid lacquer layer is greater than 1 m/sec.

(44) A ninth aspect of the method according to the sixth aspect is that the lacquer droplets consist of a different material than the liquid lacquer and after impact they undergo a chemical reaction with the liquid lacquer, which changes the surface optically and/or haptically at the respective locations.

(45) A tenth aspect of the method according to the sixth aspect is that the lacquer droplets consist of a different material than the liquid lacquer and after a physical reaction due to impact onto the liquid lacquer they volatilize within less than 5 minutes by evaporation.

(46) An eleventh aspect of the method according to one of the previous aspects is that at least one intermediate layer is applied between the workpiece and the first lacquer layer.

(47) Another aspect of the invention is an apparatus for performing the method according to one of the preceding aspects with: A a coating station and a device for feeding the workpiece to the coating station; B a first printing station for applying a first liquid lacquer with a coarse structuring to the workpiece over the entire surface area, in which a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm; C a station for at least partial curing the first lacquer; D a station for applying a second liquid, at least partially transparent lacquer for producing a fine structuring in some regions, and E a station for curing the second lacquer, wherein the difference in thickness in the region of the fine structuring on the second lacquer layer is less than 50 μm, in particular less than 30 μm.

(48) A further aspect of the invention is a workpiece, in particular a plate-shaped workpiece, comprising a wooden workpiece, a carrier material on which at least one decorative image is printed, and at least one lacquer layer having a coarse structuring, in which a difference in thickness between thicker regions and thinner regions is at least 50 μm, in particular at least 100 μm, and at least one second lacquer layer comprising an at least partially transparent material having a fine structuring, in which the difference in thickness is less than 50 μm, in particular less than 30 μm.

(49) A further aspect of the workpiece according to the preceding aspect is that the first lacquer layer has a layer thickness between 100 and 500 μm.

(50) A third aspect of the workpiece according to one of the two previous aspects is that the second lacquer layer has a layer thickness between 10 and 100 μm.

LIST OF REFERENCE SIGNS

(51) 1.0 Workpiece 1.1 First base layer 1.2 Second base layer 1.3 Digitally sprayed droplets 1.4 First lacquer layer 1.5 Second lacquer layer 2.4 Grained wood areas 2.5 Wood pore 3.0 Workpiece 3.1 Light-coloured mosaic tiles 3.2 Darker mosaic tiles 3.3 Interspaces 4.1 Workpiece 4.2 Intermediate lacquer layer, e.g. adhesion base/primer 4.3 Analogously applied textured lacquer 4.4 Digital decor printing 4.5 Liquid lacquer layer 4.6 Digital printing station 4.7 Droplets