WO2011036142A1

WO2011036142A1 - Method for producing a digitally printed workpiece

Info

Publication number: WO2011036142A1
Application number: PCT/EP2010/063862
Authority: WO
Inventors: Rene Pankoke
Original assignee: Theodor Hymmen Holding Gmbh
Priority date: 2009-09-23
Filing date: 2010-09-21
Publication date: 2011-03-31
Also published as: DE102009044092A1; EP2367691B1; ES2414932T3; EP2367691A1; PL2367691T3

Abstract

The invention relates to a method for producing a digitally printed workpiece (3,20) that is flat or in the form of a strip or board, and that comprises an abrasion resistant surface. Said method is characterised by the following steps: A) provision of a digital data set for a decorative image for a digital printing device (1); B) feeding of a printable workpiece (3, 20) into the printing device (1); C) digital printing by means of the printing device (1) using at least one printing ink (6) that contains acrylate and that is cured by radiation; D) curing of said printing ink (6); E) impregnation of the printed workpiece (3, 20) with a resin mixture (19) that contains a wetting agent; and F) curing the resin mixture (19) which contains the wetting agent by means of a heat press (106), preferably a double belt press (14) or short-cycle press (15).

Description

Method for producing a digitally printed workpiece

The invention relates to a method for producing a digitally printed flat, web-shaped or plate-shaped workpiece, for example a kitchen worktop, a furniture front or a laminate floor part with a decorative and resistant surface.

In order to speed up the manufacture of such a workpiece and to be able to react flexibly, digital printing methods, e.g. Inkjet printing process (inkjet) used. The difficulty with the inkjet jerk process is that the inkjet printheads used are very difficult to handle in industrial production with UV-crosslinked water-based inks. Some inks, after being cured by UV radiation, may subsequently become impregnated with a water-based resin solution as a barrier to subsequent impregnation of such a printed workpiece, resulting in a permanent bond between the printed workpiece and underlying other paper layers or an underlying plate, e.g. Prevent a wood-based panel or other material layers. It comes with such a product in retrospect to detachment.

It is therefore an object of the present invention to provide methods for the production of a digitally printed flat, web-shaped or plate-shaped workpiece with a durable surface and a layer-wise construction, in which a permanent connection of the individual layers is ensured.

The object is achieved by a method with the Merkmaien of claim 1.

Advantageous embodiments of the invention are contained in the subclaims.

In this case, a digitally printed flat, web-shaped or plate-shaped workpiece with an abrasion-resistant surface is produced as follows:

First, the provision of a digital data record for a decorative image. This is sent on the basis of a computer to a digital printing device.

Anschiuss is followed by feeding a printable workpiece to the printing device.

Subsequently, the digital printing of the respective workpiece by means of the printing device. In this case, a digital ink-jet printing method is used, which uses an acrylate-containing radiation curing ink. In this case, a certain minimum penetration depth of the ink is achieved in the paper.

The printing is followed by hardening of the printing ink by irradiation.

The cured acrylate layer initially acts as a kind of barrier layer compared to conventional aqueous resin solutions. A detachment of the printed workpiece from a material layer, e.g. a backing plate, can be prevented by impregnation with a wetting agent-containing resin mixture.

The impregnation of the printed workpiece with a resin mixture can be done, for example, by soaking, wetting or spraying the workpiece with the respective resin mixture.

In this case, in addition to the aqueous resin mixture, in particular melamine resin, a wetting agent additive is used, which only allows a penetration of the resin mixture or melamine resin through the acrylate layer in the predetermined paper depth. As a wetting agent, various chemical substances can be used, in particular surfactants.

The curing of the resin mixture takes place, for example, in the case of aminoplasts by crosslinking polymer strands as a result of a condensation reaction known per se with the aid of a heating press, preferably a short-cycle press or a double-belt press. The method according to the invention makes it possible to produce a workpiece with a resistant surface and a layered structure, in which a permanent connection of the individual layers is ensured. This is achieved by a wetting agent-containing resin mixture, which penetrates the workpiece surface much better than conventional resin mixtures, for example, when using a decorative paper as a workpiece, it may come to a complete penetration of the paper. In a further process step, the then dried impregnated paper is cured in a hot press.

This allows decorative coated workpieces such as e.g. Kitchen worktops, kitchen furniture fronts, other furniture fronts or laminate flooring and similar workpieces are produced with decorative surfaces. The reproduction of a wood structure or a stone structure, fantasy decors or other nature-inspired decors can be achieved, the workpieces at the same time also have positive physical properties such as abrasion resistance, scratch resistance, heat resistance.

For impregnation, it is advantageous to use a wetting agent-containing resin mixture with a wetting agent content of 0.02-2% by weight, preferably 0.1-0.5% by weight, based on the total weight of the wetting agent-containing resin mixture, since this proportion of wetting agent provides optimum penetration of the resin mixture is achieved in the surface of the workpiece, without affecting the transparency or the optical coloring of the resin layer.

Ais surfactants or surfactant mixtures can advantageously be used as wetting agents. These wetting agents reduce the surface tension between the printed workpiece and the resin used in the impregnation and thus cause a sufficient impregnation of the printed by the process according to the invention workpiece with the resin mixture.

It is of advantage if the curing of the acrylate-containing printing ink takes place by means of UV radiation (radiation in the ultraviolet range: 1-380 nm). This radiation is contained in the sunlight and thus easily available. UV lamps with a UV radiation range can also be used. It is UV Radiation easy to handle. Other radiation ranges can be used for curing.

The rate of curing can advantageously be accelerated if the printing inks have photoinitiators which accelerate polymerization or crosslinking of the acrylate units.

It is also advantageous if the digital printing using at least one UV-curing printing ink takes place, comprising at least a penetration depth of ^10μ η τι in a zeliulosehaltiges workpiece. As a result, a detachment of the ink in further processing steps, such as when rolling up the decor paper is prevented.

It is advantageous if the UV-curing printing ink is only partially crosslinked during curing by a correspondingly lower radiation dose, preferably from 20 to 80%, particularly preferably from 30 to 65%. This allows a multi-color printing process to be split. Thus, after the printing of two colors, a first curing (pinning) of these colors can first take place. Then two more colors can be applied.

For impregnation, one or more unprinted material layers, which are provided with the wetting agent-containing resin mixture, above and / or below the printed workpiece are arranged so that the flow of resin from these layers of material impregnates the non-resinated, printed workpiece during the pressing process. In this case, both material layers and the workpiece, for example, consist of absorbent materials such as paper.

It is advantageous if, after impregnating the printed workpiece or arranging a material layer impregnated with resin mixture on or under the printed workpiece, the workpiece can be applied to one or more layers of material, which are then joined together by pressing. Thus, for example, an impregnated and printed decorative paper on a wood-based panel, preferably a chipboard, MDF or HDF board, are applied, whereby a lamination of a bending resistant substrate. It is advantageous if, after impregnating the printed workpiece with the resin mixture or arranging at least one unprinted impregnated material layer above and / or below the workpiece, a subsequent pre-drying of the resin mixture takes place. As a result, a pre-crosslinking of constituents of the resin mixture can be achieved, so that optionally a further impregnated material layer or a further impregnated and printed workpiece can be applied to the resin layer.

It is advantageous if in the processes described above, an elamine resin-based and / or phenolic resin-based resin mixture is used, as this material can penetrate the workpiece under pressure and in an underlying material layer, such as a fiberboard, penetrate and after the curing of the resin mixture insoluble Connection with the material layer is received. In addition, meiamin resin is resistant to moisture after curing. In this case, melamine is a resin which gives a paper a transparent or translucent appearance, while phenolic resin is an optically colored resin.

It is advantageous if the curing of the resin mixture is carried out by a continuous double belt press. This press allows both the processing of continuous material and piece material with a high processing speed. It is particularly advantageous if the double belt press further, non-printed, impregnated material layers, especially paper layers are pressed with the printed and impregnated workpiece. Since the feeding of the material layers can be made as continuous material, the double belt press offers a higher throughput than, for example, a short-cycle press due to its continuous operation. Subsequently, the further processing of the material, for example by structuring the surface done.

It is in the compression of a layer sequence of one or more unprinted, impregnated material layers, in particular paper layers, a layer of the pre-printed and optionally impregnated workpiece and a further material layer, in particular a wood-based panel, to a solid, cured unit advantageous if this compression is performed in a pressing operation of a short-cycle press. Thus, several layer follow and thus several work steps are done at a press cycle of less than 1 minute at the same time.

In the following, the invention and the individual method steps will be described in more detail with reference to attached FIGS. 1-11. They show:

Fig. 1: Schematic representation of three inventive

Process steps B), C) and D);

Fig. 2: Schematic representation of a method step E) according to the invention;

Fig. 3: Schematic representation of two process steps E) and F) according to the invention;

Fig. 4: Schematic representation of two alternative process steps E) and F) according to the invention;

5: Schematic representation of an embodiment variant with a perforation unit

6 shows a schematic representation of the layer sequence of a further embodiment variant of a workpiece produced by the method according to the invention;

FIG. 7: Schematic representation of the layer sequence of a further embodiment of a workpiece produced by the method according to the invention; FIG.

8: Schematic representation of the layer sequence of a further embodiment variant of a workpiece produced by the method according to the invention;

9 shows a schematic representation of the layer sequence of a further embodiment of a workpiece produced by the method according to the invention; 10 shows a schematic representation of the layer sequence of a further embodiment variant of a workpiece produced by the method according to the invention;

11 shows a schematic representation of the layer sequence of a further embodiment variant of a workpiece produced by the method according to the invention;

1 schematically shows feeding by means of a feed unit 102, printing of a decorative paper 3 by means of a digital printing unit 103 and curing of the printing inks by means of an irradiation unit 104 in the decorative paper by a printing device 1. The digital printing can i.a. take place directly on a wooden surface 20 or, as shown by way of example in FIG. 1, onto a decorative paper 3 unwound from a roll 2.

In this case, the printing device 1 to a printer 4, which has four printheads 5. These give according to the invention from UV-curable ink 6 on the surface of the decorative paper 3 from. In this case, a monochrome or multicolor printing of the workpiece is possible.

Following the printing of the workpiece, curing of the printing ink takes place by irradiation with the UV illuminant shown schematically

7th

After printing, the decorative paper 3 can be rolled up for storage on a roll 8.

The manner of feeding a workpiece depends on its material properties. Paper sheets can be clamped and unrolled, while wood-based panels are fed on treadmills of the printing device.

The printheads 5 can be arranged stationarily in the printer 4 in order to realize a single-pass printing process. In this case, the print heads can advantageously extend over the entire width of the area to be printed. The individual print heads have, for example, a width of 70 mm and are next to each other in a printing module, preferably with the UV-curing printing inks. black, mangenta, cyan and yellow. The inks may include, for example, acrylate prepolymers, color pigments and photoinitiators. If several printing modules are arranged side by side, it is also possible to print workpieces, for example with a width greater than 1 m. The arrangement of several printing modules stationary next to each other allows a uniform multi-color print image on which no transitions between the individual printing modules can be seen.

Alternatively, the printheads 4 in the arrangement can also be arranged on a carriage, so that a printing of the workpiece can be carried out in the multi-pass method.

The above-described stationary and movable printhead assembly may also be arranged in a multi-row succession to achieve a higher printing speed compared to a single-row arrangement. As an alternative to a printhead arrangement, nozzle bars may also be arranged.

It can also be used instead of four and six or more inks in the printing device 1 depending on the embodiment.

Fig. 2 shows the process step of impregnating the workpiece with a wetting agent-resin mixture 19 through an impregnation unit 105, e.g. with an amino resin (melamine resin mixture) which, for example, comprises 0.3% by weight of a surfactant. The surfactant lowers the surface tension of the barrier layer of the UV-cured ink 6, so that the resin can penetrate this layer. The previously printed decorative paper 3 is unwound from the roll 8, drawn through a resin bath 9 with the liquid netzmittelhal- term resin, squeezed off excess resin by means of a squeegee 10 and then dried by a dryer 11 shown schematically. This dryer 1 is designed such that it allows drying of the resin. For example, the dryer 11 may be formed as a circulating air or hot air dryer. After drying the resin, the workpiece can be wound up for storage on another roll 2.

As an alternative to winding on the roll 12 may also be provided a cutting device, not shown, to cut the impregnated and dried paper in sheets. FIG. 3 shows, as an alternative to impregnation, the method step of arranging two unprinted paper layers 17 through a coating unit 107, which is impregnated with a wetting agent-containing resin mixture 19, above and / or below a printed Hoiz workpiece 20.

In the same way, it is also possible to apply a printed and impregnated decor paper 3 above or below a wood-based panel 13 through a coating unit 108. In this case, the printed and impregnated decorative paper 3 is unwound above and below the wood-based panel 13, and this package thus brought together is subsequently cured in a double-belt press installation 14.

The curing of the resin mixture takes place in a curing unit 107. The bonding of the individual layers with the respective printed workpiece takes place in a heating press. As a heating press 106, a double belt press 14 with two rollers 15 and a feeder for the Holzwerkstoffpiatte 13 is shown.

An alternative embodiment of the method step of connecting the printed decorative paper 3 with the wood-based material plate 13 by a heating press 106 is shown in Fig. 4. Here, a package made of wood-based panel 13 and arranged above and below printed and impregnated decor paper 3 in a heated short-cycle press 16 and cured.

FIG. 5 shows the schematic structure of a device for producing the mechanically perforated decorative paper. From a roll 23, the non-resin decorative paper 3 is unwound. It then passes under a printing device 1 and a UV lamps 7 for drying through and is then equipped with a spike or similar mechanical perforation roller 24 and a correspondingly configured counter-roller 25, in a possible embodiment, the spines of the spiked roller 24 in each case run out executed recesses of the platen roller 25 and so perforated between two rolls already printed decorative paper 3 perforate. Subsequently, the perforated and printed decorative paper 3 is wound up on a roll 26 again. In an alternative embodiment, this decorative paper may also be slightly or more strongly dented before unwinding from the roll 23. FIG. 6 shows a suitable printable paper 3, which is printed on the surface with a UV-curable ink 6. It can be seen that depending on the decorative image used, the surface of the paper 3 is more or less covered by the printing ink 6. In a very bright decor, which results in the inventive method to a printing with about 3 g of printing ink / m ² surface area, a high permeability of the printing ink 6 for the wetting agent-containing Meiaminharzgemisch 9 is given. When printing the surface with a dark decor, which leads to an occupancy of the surface with usually 10 g or more per m ² surface, a poorer permeability is given, which would be given according to the prior art without the inventive method no permeability. The resin bath 9 with the Meiaminharzgemisch indicates the subsequent post-printing impregnation in which the melamine resin penetrates through the applied ink layer of digital printing ink in the paper.

Figure 7 shows a cross section through a printable paper 3, which is already printed with the ink 6, and then after the process step of impregnation with Netzhaitigen Meiaminharzgemisch 19. It can be seen that here the Meiaminharzgemisch with the wetting agent additive through the layer of digital ink through penetrated into the paper 3 and this was completely impregnated.

FIG. 8 shows a section of the layer-wise coated workpiece from the printable paper 3, which has been printed with the digital printing ink 6 and which has been impregnated with meiamin resin mixture 19 containing wetting agent. Subsequently, the workpiece made of paper 3 with a wood material plate 13 was provided as a support plate, which was firmly and permanently connected to the paper 3 in the process step of hot pressing. It is important that in the process step of hot pressing the wetting agent Meiaminharzgemisch, which is penetrated in the step of impregnation in the paper 3, penetrates from the paper 3 in the surface of the wood-based panel 13 and cures there and thus forms the connection.

In addition, it can be seen in FIG. 8 that the resistant surface formed after the end of the last process step consists of hardened melamine. Resin 19 may contain a corresponding embossed surface structure, which are produced by the use of embossing plates in a short-cycle press or embossing bands in a continuous double belt press. In an alternative embodiment, this surface structure 27 can be formed by a further resinated paper without decorative printing, that is to say an overlay paper 17. This overlay paper 17 is connected and patterned in the same pressing process with the printed piece of paper 3.

FIG. 9 shows a basic structure for a possible variant of the method according to the invention, in which a paper 3 preimpregnated with melamine (without wetting agent) is printed with the UV printing ink 6. In addition, a melamine resin-impregnated overlay paper 17, which is transparent and unprinted, placed. Between layers 3 and 17, a wetting agent is applied to the UV printing, e.g. sprayed. Under the printed prepreg is placed another resinated but unprinted underlay paper 17 'and this coated paper 3 is coated with a wood-based panel 13, e.g. Span- or MDF support plate provided. The underlying structure on the back of the support plate can be constructed identically to the structure above. The package thus formed is then pressed in a hot press and thus inseparably connected to each other (not shown in Figure 4).

FIG. 10 shows a further alternative embodiment of the method according to the invention. In this case, the decorative paper 3 is unmanaged, i. not impregnated, but printed as in the other variants with the UV-curable ink 6. The package to be subsequently pressed is additionally formed from an overlay paper 17 impregnated with melamine resin mixture and an appropriate admixture of wetting agent 28 and an underlying underlay 17 also impregnated with melamine resin 19 and wetting agent mixture 28. Under the wood-based panel 13 as a support plate, the structure may be identical as above the plate.

FIG. 11 shows a further alternative embodiment of the method according to the invention. In this case, a printed unbeharztes decorative paper on mechanically caused small holes 29 (perforation). The printing with the UV ink 6 on the decorative paper 3 may be before or in an alternative embodiment, even after the mechanical production of the holes (perforation) in decorative paper. Through these holes can during during the subsequent pressing process in the hot press penetrate the melamine resin 19 from the impregnated underlay 17 and overlay 17 'better through the ink layer of UV ink 6 and make a complete solid connection. On the underside of the wood material board 13, the same structure as indicated on the upper side, but after a theoretical interim hot pressing process. As a result, the melamine resin with or without wetting agent has completely soaked the mechanically perforated decorative paper 3 and also the uppermost layer of the wood-based material carrier plate. This so-pressed structure is shown.

In addition, a wear protection layer may be applied, possibly also in conjunction with wear layer 21 sprinkled during the curing, in particular with corundum (Aiuminium oxide (Al 2 O 3)).

In the following, a detailed example of the method according to the invention will be described.

In this exemplary embodiment of the method according to the invention, first of all a digital data record for a decorative image to be printed, for example a wood optic, such as e.g. an oak decoration or the like, for the digital printing apparatus, for example, by a computing unit 101.

Subsequently, a suitable printable workpiece is fed to the printing device via a feed unit 102. This workpiece may be formed as decorative paper 3 or wood-based panel 20

A decorative paper 3 is preferably a paper having a basis weight of 40-100 g / m ² , more preferably 60-100 g / m ² , and a residual moisture before printing 0.5-8% (weight percent) of water in the paper, more preferably 1.5-2.5% (weight percent). The decorative paper consists of fibers, for example natural fibers and additives and bleaching agents, for example titanium dioxide (T1O2) for whitening.

In the next process step, this decorative paper provided is printed in the digital printing device (103) with a UV-curing printing ink. This digital printheads are used, which have a nozzle opening size of 10 - 100 pm, more preferably 15 - 40 m in diameter. Of these digital printheads, at least one printhead per color, that is, four Color print at least four printheads, provided in the device. In an alternative embodiment, however, a plurality of print heads per color may also be arranged in the printing device in order to achieve a greater printing capacity. In a particular embodiment, the digital printheads may be fixedly disposed over most or all of the width of the media to be printed. In this case, the paper moves under the fixed print heads.

The UV ink used contains pigments as colorants, ie solids which have a high to very high color stability. This color stability, according to the known Woll scale, is between 5 and 8, more preferably 6-8. The pigments used have an average particle size of 0.01 to 5 μm, more preferably 0.1 to 3 μm. The proportion of the pigments based on the total weight of the radiation-curing digital printing ink used is 0.4-25%, particularly preferably 1-10%.

As further constituents in the digital ink used, hardening, ie polycrystallizing, acrylates are provided. These are already present as polymers or prepolymers and as a mixture with monomers which have a lower viscosity and act as a reactive diluent. These acrylates, ie polymers and monomers, form the main constituent of the radiation-curing UV printing ink.

Further constituents are one or more photoinitiators with a percentage by weight of 0.1-25%, more preferably 1-10%. As photoinitiators, e.g. Triaryl sulfonium Saize or with diaryl-iodonium salts in question. However, it is also possible to use other photoinitiators which represent a different reaction rate at different wavelengths of UV radiation used.

In addition, a number of different additives (additives) are used, which positively influence the physical properties of the printing ink (viscosity, electrical conductivity, stability, homogeneity).

In the digital printing of the decorative paper used with the above-described digital printing ink according to the inventive method is a Penetration depth of the UV ink in the decorative paper of 25 - 80%, particularly preferably 40 - 70%, based on the total thickness of the decorative paper.

This is therefore important for the method according to the invention, so that a clear print image is formed and no excessive intermingling of the individual digitally printed droplets with too great a penetration depth. However, if the penetration depth is too low, a completely impermeable layer of the then polymerized acrylates immediately forms on the surface of the decorative paper, so that further processing by the process according to the invention is no longer possible.

In an alternative embodiment of the method according to the invention, a slightly reserved decorative paper, e.g. with a melamine resin mixture used. The proportion of melamine resin after drying is 2-3%, preferably 5-15% (weight percent). In this so-reserved paper, a penetration depth of the UV ink based on the total thickness of the paper of 10 - 50%, more preferably 15 - 40%, is produced. The decorative papers used have a thickness of 60-300 gm, more preferably of 80-200 μιτι.

In the next step, the decorative paper thus printed is passed under a UV radiation source of a UV irradiation unit 104 and thus the UV ink is cured, ie there is a crosslinking of the acrylates contained in the UV ink instead. This crosslinking can be complete, but in an alternative embodiment, it can also be carried out to 50-95%. The sources of radiation for the process according to the invention are both UV LEDs and conventional UV emitters, each with an emission maximum between 150 and 380 mm, that is, depending on the selected photoinitiators in the UV-A, UV-B or UV-C range, in question. In a further alternative embodiment and with reference to FIG. 5, the decorative paper printed and cured according to the invention is subsequently perforated in a mechanical process, ie provided with small holes which likewise ensure improved penetration of the melamine resins subsequently used in the impregnation. This perforation can take place, for example, with a chopper roll or similar mechanical instruments. The diameter of the perforation holes in the paper according to the method of the invention between 1 and 0.01 mm, more preferably between 0.5 and 0.05 mm to choose. The perforation holes are made according to the invention The method is chosen so that after the compression step, there are no more holes left visible (viewing distance 0.5 - 2 m). In order to ensure a good adhesion of the layers to one another, the spacing of the holes in the method according to the invention is between 0.1 mm and 10 mm, preferably between 0.5 and 3 mm (in each case from one hole to the next).

In the next step of the process according to the invention, the thus printed and cured decorative paper is impregnated in an impregnation unit 105 with an aqueous melamine resin mixture. Crosslinkable aminoplastic resins are used according to the process of the invention. In an exemplary embodiment, condensation products, ie etherified products of melamine, urea-formaldehyde mixtures or melamine-formaldehyde mixtures are used. To this resin mixture is added a hardener, usually 0.01-2.5% (weight percent) based on the final resin mixture. As curing agents come e.g. organic sulfonic acids or carboxylic acids are used. This aqueous resin mixture with a solids content of 40-70% based on the aqueous solution is then a wetting agent in a concentration of 0.02 to 2% based on the total weight, particularly preferably 0.1 to 0.5%, added.

Wetting agents by the process according to the invention may be anionic or cationic surfactants. In an exemplary embodiment for anionic surfactants, e.g. Sodium, potassium, almonium salts of sulfonic acid, sulfonated fatty alcohols or ethoxylated fatty alcohols are used, as cationic surfactants in an exemplary embodiment e.g. Polyethylene glycol or polyvinyl alcohol.

These wetting agents reduce the surface tension between the printed decor paper 3 and the resin used in the impregnation and thus cause a sufficient impregnation of the decorative paper 3 printed by the method according to the invention with the resin mixture 19.

In an alternative embodiment, the printed and cured with UV rays decorative paper 3 may remain unimpregnated and only a blank overlay 17 and / or an unprinted underlay 17, so a white, later after pressing transparent paper, impregnated with the illustrated aqueous resin mixture and the wetting agent additive. In this case, the overlay 17 and underlay paper 17 "is arranged on the surface of the decorative paper 3 by a coating unit 107. In this illustrated embodiment, the added wetting agent achieves good resin flow from the overlay and / or underlay paper 17 into the non-resinated but with the UV Ink 6 printed decorative paper 3 during the pressing process in a hot press.

After the impregnation step softens after soaking

Decor paper and / or the overlay or Underiay paper with the illustrated resin mixture and a subsequent drying of the resinated paper to a residual moisture content of about 3 - 20% (weight percent), more preferably 5 - 10% (weight percent) is completed, follows the hardening of the resin,

In the final method step, a package structure is formed from a wood material carrier plate 13, which is covered on one or both sides with the printed and impregnated decorative paper 3,

In an alternative embodiment, the wood-based panel 13 is covered with the printed but not impregnated decorative paper 3, wherein between

Decorative paper and wood material plate is still a mixed with resin mixture and wetting agent underlay paper 17 is placed.

In an alternative embodiment, an overlay paper 17 impregnated with resin mixture and wetting agent may be applied to the package thus formed. The same package formation can be placed on the underside of the wood-based panel. This so composed of different layers package is then in a hot press 106 under a pressure of 20 - 60 bar, more preferably 30 - 40 bar, and a temperature of 150 - 230 ° C, more preferably 170 - 200 ° C, pressed.

In this case, smooth or structured embossing plates 110 can be used, which process or structure the surface of the formed package. During this pressing process, the aqueous dried resin mixture becomes liquid within the first few seconds and then forms a completely soaked composite between the various paper layers and the uppermost cover layer in the wood-based panel (chipboard, MDF or HDF board). In the further seconds of pressing, which usually takes between 5 and 30 seconds, hardens the melamine resin and forms an irreversibly cured, highly resistant surface.

In an alternative embodiment, the top or one of the top impregnated but not printed papers may additionally be provided with a corundum 21 (Al ₂ O ₃ ) or other solids to increase the abrasion resistance of the product being produced, eg for use as laminate flooring.

Likewise, in an alternative embodiment for pressing instead of a short-cycle press 15, a continuous double belt press 14 with a corresponding embossing belt, usually a chromed steel belt, are used.

reference numeral

1 printing device 21 corundum particles

2 roll 23 roll

3 decorative paper 24 spiked roller

4 Printer 25 Counterpressure roller

5 printheads 26 rolls

6 printing ink 27 Surface structure

7 UV lamps 28 Wetting agents

8 roll 29 holes

9 resin bath

10 nip rolls

11 dryers

12 roll

13 wood-based panel

14 double belt press

15 roll

16 short-cycle press

17 overlay paper

17 'Underlay paper

18 decorative paper

19 resin mixture

20 wooden workpiece plate

101 arithmetic unit

102 Feeding unit

103 digital printing unit

104 UV irradiation unit

105 impregnation unit

06 heating press

107, 108 coating entity

110 embossed bites

Claims

claims

1. A method for producing a digitally printed flat, web-shaped or plate-shaped workpiece (3, 20) with an abrasion-resistant surface, characterized by the following steps:

A) providing a digital record for a decorative image for a digital printing device (1);

B) feeding a printable workpiece (3, 20) to the printing device

(1);

C) digital printing by means of the printing device (1) using at least one radiation-curing acrylate-containing printing ink (6);

D) curing the printing ink (6);

E) impregnating the printed workpiece (3, 20) with a resin-containing resin mixture (19); and

F) curing the netzmitteihaltigen resin mixture (19) by means of a heating press (14, 15, 106).

I. The method of claim 1, characterized in that for impregnating a Netzm ittelhaltigen resin mash with a proportion of wetting agent of 0.02 to 2 weight percent, preferably 0.1 to 0.5 weight percent, based on the total weight of the netzmitteihaltigen resin mixture used becomes.

3. The method according to claim 1 or 2, characterized in that for impregnating a wetting agent-containing resin mixture, wherein the wetting agent contains at least one surfactant or a surfactant mixture is used.

\. Method according to one of the preceding claims, characterized in that the acrylate-containing printing ink is cured under UV radiation.

5. The method according to any one of the preceding claims, characterized in that the digital printing in step C) using at least one radiation-curing acrylate-containing printing ink (6), which has at least one photoinitiator takes place.

5. The method according to any one of the preceding claims, characterized in that the digital printing in step C) using the at least one curing by radiation printing ink (6), which has a penetration of at least 10μιτι in a cellulosic workpiece (3, 20)

7. The method according to any one of the preceding claims, characterized in that the UV-curing printing ink (6) during curing by a correspondingly lower radiation dose is only partially crosslinked, preferably 20 to 80%, particularly preferably 30 to 65%.

3. The method according to any one of the preceding claims, characterized in that for impregnating the digitally printed workpiece at least one impregnated with a Netzmittelhaltigem resin mixture material layer (17) applied at least on one side of the workpiece (3, 20) and then cured by means of a heating press.

9. The method according to any one of the preceding claims, characterized in that after the step of impregnating the printed workpiece (3, 20) with the reticulated resin mixture (19) applying the workpiece (3, 20) above or below one or more material layers (13) takes place and during the curing, a joining of the workpiece (3, 20) with the material layer (13).

10. The method according to any one of the preceding claims, characterized in that after the step of impregnating the printed workpiece (3, 20) with the netzmittelhaitigen resin mixture (19), a subsequent pre-drying of the resin mixture (19).

11. The method according to any one of the preceding claims, characterized in that for impregnating the printed workpiece (3, 20) or the unprinted material layer (17) a wetting agent-containing resin mixture (19) on Me ~ laminharzbasäs and / or phenolic resin-based is used.

12. The method according to any one of the preceding claims, characterized in that prior to curing further impregnated material layers (17), in particular paper layers, at least on one side on the printed impregnated workpiece (3, 20) or the one or more material layer (13) are arranged.

13. The method according to any one of the preceding claims, characterized in that takes place during or after curing of the wetting agent-containing resin mixture, a surface treatment for producing a decorative laminate.

H.Verfahren according to any one of the preceding claims, characterized in that each pressing operation of the short-cycle press (15) the layer sequence of one or more impregnated material layers, in particular paper layers (17), a layer of the pre-printed and optionally impregnated workpiece (3, 20) and a further material layer, in particular a wood-based panel (13), are pressed into a solid, hardened unit.

15. The method according to any one of the preceding claims, characterized in that the printed workpiece (3, 20) after printing and before or after the curing of the ink (6) is mechanically perforated or the workpiece to be printed (3, 20) the printing is mechanically perforated.