EP3351402B1 - Method for producing a panel with a decoration layer - Google Patents

Description

The present invention relates to a method for producing a material layer provided with a decorative layer according to claim 1.

description

Decorated wood-based panels are often used to make floor laminate or in the form of wall and ceiling trim elements.

For decorating such wood-based panels there are several approaches. So there is a possibility in the coating of wood-based panels with a decorative paper, the variety of differently patterned decorative papers are no limits. As an alternative to the use of decorative papers on wood-based panels, the possibility of direct printing of the wood-based panels has increasingly developed, with a printing of paper and its subsequent laminating or direct coating accounts for the wood-based panels. The printing techniques mainly used for direct printing are gravure printing and digital printing.

The decorative layers are then provided with a wear protection layer and the layer structures, for example, pressed together in a short-cycle press. During further processing in the short-cycle press surface structures can also be produced in the surface using a structured press sheet.

Two types of three-dimensional surface structures are known in the prior art: the synchronous (or decorsynchronous) structure and the asynchronous structure.

A synchronous surface structure reflects individual elements of the printed decoration, wherein the surface structures are formed largely congruent to the decor. For wood decors, the structures may be in the form of pore structures that follow the grain. For tile decors, the structures may be depressions in the area of joint fill lines enclosed by the decor.

In contrast to the synchronous surface structure, an asynchronous surface structure forms a pattern that differs from the printed decor.

In both cases, the three-dimensional structures are embossed in a resin layer, in particular a wear protection layer, using suitable press plates. In the case of a synchronous structure, a pressing plate is manufactured based on the printing data of, for example, a printing cylinder or a digital printer used for direct printing.

In the case of producing a three-dimensional synchronous surface structure on a material plate, an exact positioning of the pressure plate on the printed surface of the material plate is necessary to ensure a balance between the decor and the surface structure of the pressure plate. This positioning requires complex and corresponding expensive devices. After the structured pressing plate has been adjusted with the pressure, pressing is carried out at suitable pressures and temperatures. The resulting three-dimensional synchronous surface structure reflects the surface of the press plate.

In the case of an asynchronous surface structure, it is not important to exactly match the pressure plate and pressure layer on the wood-based panel. As a result, in asynchronous surface structures, there are visual differences between the printed decor such as a wood grain and the introduced three-dimensional structures. Asynchronous surface structures are often used in lower quality laminate products for mass production.

The known methods for the production of three-dimensional surface structures on wood-based panels therefore require pressing plates with different 3-dimensional surface structures. The structuring of the press plates takes place in etching processes in which the press plates are provided, for example, with a wooden pore or a relief structure. This can be achieved by complex measures in the structuring and the subsequent chrome plating of the press plate, a gloss level difference between the pore and the other areas.

In effect, this means that for each desired surface structure, a corresponding press plate must be made. Any change in the final surface structure requires the provision of a corresponding surface-structured press plate and replacement of the press plate in the press, which results in interruption of the press surface Manufacturing process required. In particular, the introduction of synchronous surface structures on material boards is therefore associated with considerable costs.

From the EP 1053382 B1 is a method of making a door provided with a decor, the decor simulating a 3-dimensional structure. For this purpose, a plurality of primer layers, decorative layers and protective layers are applied to a suitable substrate, such as an MDF fiberboard. The primer layers used are acrylic-containing components or vinylacrylic copolymers. The printing ink used for the wood decorating pattern may be a so-called "puffy" ink which expands after a thermal treatment. This expanding ink can give the decor the appearance of a 3-dimensional structure. However, pressing in a short-cycle press under pressure does not take place in this case.

The present invention is therefore the technical object of providing optical surface structures on material plates or carrier plates by a method which can dispense with the use of structured press plates. The optical surface structures are intended to be generated exclusively by gloss difference. In addition, other decorative effects are to be made possible by the process.

The object is achieved according to the present invention by a method having the features of claim 1.

• Bereitstellen von mindestens einer Werkstoffplatte aus einem Holzwerkstoff oder einem Holzwerkstoff-Kunststoff-Gemisch mit einer Oberseite und einer Unterseite,
• Auftragen von mindestens einer Harzschicht und mindestens einer Grundierungsschicht auf die Oberseite der Werkstoffplatte;
• Auftragen von mindestens einer Dekorschicht im Direktdruck auf die Oberseite der mindestens einen Werkstoffplatte, wobei die mindestens eine Dekorschicht mindestens ein Additiv in Form von gasgefüllten Mikrosphären umfasst;
• Auftragen von mindestens einer Schutzschicht auf die mindestens eine Dekorschicht;
• zumindest Antrocknen der mindestens einen Schutzschicht,
• Auftragen von mindestens einer Verschleißschutzschicht auf die Schutzschicht, wobei die Verschleißschutzschicht mit den folgenden Schritten aufgetragen wird:
  • Auftragen von mindestens einer ersten Harzschicht auf die mindestens eine Schutzschicht;
  • gleichmäßiges Aufstreuen von abriebfesten Partikeln auf die erste Harzschicht;
  • Trocknen der mit den abriebfesten Partikeln versehenen ersten Harzschicht in mindestens einer Trocknungsvorrichtung;
  • Auftragen von mindestens einer weiteren Harzschicht auf die getrocknete mit den abriebfesten Partikeln versehene erste Harzschicht, und
  • Trocknen der weiteren Harzschicht; und
• Verpressen des Schichtaufbaus in einer Kurztaktpresse bei Temperaturen zwischen 150 und 250°C und einem Druck zwischen 100 und 1000 N/cm2, wobei die gasgefüllten Mikrosphären expandieren.

Accordingly, a method is provided for producing a material layer provided with a decorative layer, which comprises the following steps:

• Providing at least one material plate of a wood material or a wood material-plastic mixture with a top side and a bottom side,
• Applying at least one resin layer and at least one primer layer to the top surface of the material plate;
• Applying at least one decorative layer in direct printing on the top of the at least one material plate, wherein the at least one decorative layer comprises at least one additive in the form of gas-filled microspheres;
• Applying at least one protective layer to the at least one decorative layer;
• at least drying the at least one protective layer,
• Applying at least one wear protection layer to the protective layer, wherein the wear protection layer is applied by the following steps:
  • Applying at least one first resin layer to the at least one protective layer;
  • uniform spreading of abrasion-resistant particles on the first resin layer;
  • Drying the first resin layer provided with the abrasion-resistant particles in at least one drying device;
  • Applying at least one further resin layer to the dried first abrasion resistant particles provided with the first resin layer, and
  • Drying the further resin layer; and
• Pressing the layer structure in a short-cycle press at temperatures between 150 and 250 ° C and a pressure between 100 and 1000 N / cm 2, wherein the gas-filled microspheres expand.

Accordingly, a method is provided in which by applying a decorative layer using a printing ink with gas-filled microspheres as an additive or additive, an optical structure effect is achieved.

This printing ink, which consists essentially of the binder and an additive usually used in the printing process, generates a degree of gloss difference due to the gas-filled microspheres during the pressing in the pore.

As explained in more detail below, gravure printing and digital printing can be used as printing techniques for direct printing. In this case, the ink is applied in gravure with a pore roll. In digital printing, this color is coupled to the black (key) via the software. Here, the additional color is also printed from a certain amount of black. Another possibility is the microspheres directly to the printing ink for the pore or the black mix. Of course, the process can also be started with a digital print where the decor is printed. Thereafter, a colorless ink is then printed with microspheres in the region of the pores with a pressure roller. The color may alternatively contain color pigments.

In a preferred variant, first a first decorative layer (without gas-filled microspheres) is applied by gravure or digital printing, to which in turn the decorative layer containing the gas-filled microspheres is applied in gravure or digital printing. Various variations in the number of decorative layers with and without gas-filled microspheres are conceivable here. Accordingly, more than one decorative layer can be applied by direct printing.

The gas-filled microspheres applied with the decorative layer expand at the high temperatures prevailing in the final pressing step. This expansion of the gas-filled microspheres results in a change in the surface area and an associated gloss level difference in the applied print decor which reduces the optical differences, e.g. reflected in the grain in a decorative grain.

The present method thus enables the provision of an optically three-dimensional synchronous surface structure without the need to produce structured press plates. When using the same pressure plate different three-dimensional structures can be obtained in the final product, the structures are already determined in the printing step by the gas-filled microspheres.

In one embodiment of the present method, a chipboard, medium density fiber (MDF), high density fiber (HDF) or coarse chip (OSB) or plywood board is used as the material board.

In the case of a wood-based panel as a support plate, this has a maximum density of 1400 kg / m ³ , preferably 1200 kg / m ³ , a minimum density of 750 kg / m ³ , preferably 800 kg / m ³ , and a gross density of 850 kg / m ³ up.

According to a further embodiment of the present method, at least the upper side of the material plate is subjected to at least one grinding process. During the grinding process, a part of the surface of the material plate is abraded, whereby the Surface quality of the material plate for subsequent application of the decorative layer is improved. The process of grinding the material plate can be repeated as often as desired.

In a next step of the present method, according to the invention, at least one resin layer is applied to the upper side, in particular to the ground upper side of the material plate. This resin layer is also referred to as rolling base and serves to improve the adhesion of the primer layer on the material plate. The rolling base preferably comprises a formaldehyde resin, e.g. Melamine-formaldehyde resin, melamine-urea-formaldehyde resin or urea-formaldehyde resin. This resin layer can be applied one or more times and accordingly consist of several layers. Preferably, the resin layer (rolling base) after application, e.g. dried in a convection dryer.

Furthermore, according to the method of the invention, in a next step, at least one primer layer is applied to the upper side of the material plate, in particular to the at least one resin layer.

The primer layer preferably used in the present method comprises a composition of casein as a binder and inorganic pigments, especially inorganic color pigments. As color pigments, white pigments such as titanium dioxide TiO ₂ can be used. Other color pigments may be calcium carbonate, barium sulfate or barium carbonate. The primer contains, in addition to the color pigments such as titanium dioxide and casein, water as a solvent.

It is likewise preferred if the applied pigmented base layer comprises at least one, preferably at least two, more preferably at least four successively applied layers or jobs, wherein the application quantity between the layers or jobs can be the same or different, ie the applied quantity every single layer can vary. Thus, the application rate of a layer or an order of the primer layer can be between 1 and 50 g / m ² , preferably between 2 and 30 g / m ² , particularly preferably between 5 and 15 g / m ² per material plate.

The total amount of the applied pigmented base layer, in particular in the form of a liquid application, can be between 5 and 200 g / m ² , preferably between 10 and 150 g / m ² , particularly preferably between 20 and 100 g / m ² per material plate.

After application of the primer layer, the same is dried in at least one convection dryer. In the case of application of several primer layers or primer layers, a respective drying step takes place after application of the respective primer layer or primer layer. It is also conceivable that one or more grinding units are provided after each drying step of a primer layer for grinding the primer layers.

In the present case, in a further embodiment, at least one primer layer can be applied to the upper side of the material plate, preferably to the primer layer. The at least one primer layer preferably consists of an aqueous spatula or of a UV or EBC curable filler. The application rates of the primer can be between 1 and 10 g fl./m ² , preferably between 1 and 5 g fl./m ² , particularly preferably between 1 and 2 g fl./m ² .

In a further variant of the present method, the at least one decorative layer is applied by gravure printing or digital printing. In the case of a printed decor, a water-based pigmented ink can be gravure coated or digital-printed. This water-based pigmented ink can also be applied in more than one layer, for example two to ten layers, preferably three to eight layers.

As mentioned, the application of the at least one and optionally further decorative layers preferably takes place by means of an analog gravure printing method and / or a digital printing method. The gravure printing process is a printing technique in which the elements to be imaged are in the form of depressions in a printing form which is inked before printing. The ink is predominantly in the recesses and is due to contact pressure of the printing plate and adhesion forces on the object to be printed, such. a material plate, transferred.

In the present method, the decorative layer to be applied in direct printing with the gas-filled microspheres can be applied by direct gravure printing or indirect gravure printing. The gas-filled microspheres can be contained in one or more colors. However, it is also conceivable that the gas-filled microspheres can be applied separately.

In digital printing, the print image is transferred directly from a computer to a printing press, such as a press. a laser printer or ink jet printer. This eliminates the use of a static printing form. Both methods allow the use of aqueous inks and inks or UV-based colorants. Digital printing can be done with 1 to n single color printheads or 1 to n multi color printheads (e.g., CYMK).

When using the digital printing for applying the decorative layer, the gas-filled microspheres can be contained in one or more colors or can also be applied separately. Digital printing can also be used as a single-pass method or as a multi-pass method.

It is also conceivable to combine the mentioned printing techniques from gravure and digital printing. A suitable combination of the printing techniques can be done either directly on the material plate or the layer to be printed or before printing by adjusting the electronic records used. Thus, a first decorative layer can be applied in gravure printing and further decorative layers in gravure printing and / or digital printing, or a first decorative layer can be applied in digital printing and further decorative layers in gravure printing and / or digital printing.

In a preferred embodiment of the present method, the gas-filled microspheres are present in the at least one decorative layer in an amount between 0.1 and 50% by weight, preferably between 0.5 and 30% by weight, particularly preferably between 1.0 and 10% by weight. Very particular preference is given to amounts between 0, 4 and 5% by weight, in particular between 0.6 and 1% by weight, for the gas-filled microspheres.

The gas-filled microspheres consist of plastic beads filled with a propellant gas. Gaseous hydrocarbons such as propane, n-butane, isobutane or pentane, but also carbon dioxide can serve as suitable propellant gases. The size or diameter of the gas-filled microspheres is in the range of 1 to 200 μm, preferably 2 to 150 μm, particularly preferably 5 to 100 μm, e.g. in a range of 10 to 30 microns.

It is further preferred if the at least one and further decorative layer in an amount between 0.1 and 10 g / m ² , preferably between 0.5 and 5 g / m ² , particularly preferably between 0.7 and 1 g / m ² is applied.

In a further embodiment, the at least one decorative layer, in particular in the case of a second decorative layer containing the gas-filled microspheres, has a transparent color. The second decorative layer containing the gas-filled microspheres can also have color pigments.

As already explained above, the printing ink used for the decorative layer can be applied to the material plate in gravure printing with a second pressure roller (or pore roller). The surface of the pressure roller is structured and has micropores of various sizes for receiving the ink. The ink is transferred from the pressure roller to the material plate. By means of a suitable control, e.g. the repeat control ensures that the ink containing the gas-filled microspheres is in the same areas as the pore color.

In the case of digital printing, the ink with the gas-filled microspheres is preferably coupled to the black (key) via the software. Here, from a certain amount of black and the additional ink is also printed. Another possibility is to mix the microspheres directly to the ink for the pore or the black. Of course, the process can also be started with a digital printing, in which a first printing ink is printed as the first decorative layer. Thereafter, the second ink containing the gas-filled microspheres is then printed with a pressure roller area of the pores.

In a further variant of the present method, it can also be provided that the at least one decorative layer or the further decorative layers comprise further additives for the production of nacre or metallic luster, glitter effects, night lights or thermochromic effects.

As stated above, a protective layer is provided on the decorative layer. This protective layer serves on the one hand as a transport protection and on the other hand as a mediator, so-called primer, between layers not compatible per se, such as the decor print or decorative layer and a subsequent wear protection or other finishing layers.

In one embodiment, the at least one protective layer contains an aqueous resin, at least one radiation-cured lacquer and / or a polyurethane.

Accordingly, either a resin, preferably a water-compatible resin, a radiation-curable, typically non-water-compatible lacquer, e.g. selected from the group of acrylates, modified acrylates and / or epoxides; or polyurethanes which have good adhesion properties are applied directly. Particular preference is given to using aqueous resins. After drying (such as hardening or fishing) of the protective layer intermediate storage of the printed plates without risk of surface damage or contamination of the decorative layer is possible. Thus, even at undefined time intervals between a processing step decorative pressure and a further processing step no problems, such as contamination of plates or abrasion and / or detachment of the decoration can be expected. This also ensures that the printer does not have to stop its work in the event of a business interruption in further processing.

In one embodiment, the protective layer to be applied to the decorative layer of the material plate comprises at least one water-compatible resin, preferably a formaldehyde-containing resin, particularly preferably melamine-formaldehyde resin, urea-formaldehyde resin and / or melamine-urea-formaldehyde resin. The resin can therefore be applied in liquid form or else in solid form, the use of a liquid resin being preferred.

The protective layer acting as a transport protection can also have abrasion-resistant particles such as corundum, glass beads, cellulose fibers and other additives.

Subsequently, the protective layer comprising the at least one water-compatible resin is dried or predried until the resin is still free-flowing and crosslinkable. The drying of the water-compatible resin-containing protective layer is typically carried out in a continuous drying oven, as are known from wood-based panel manufacturing. Depending on the amount applied, the process of pre-drying may take 5 to 15 seconds, preferably 5 to 10 seconds.

If a radiation-curable lacquer is used as a protective layer, the protective layer to be applied may subsequently be applied to the protective layer by using UV radiation (eg at 320-400 nm), ESH radiation and / or NIR radiation. After setting, the paint preferably has a degree of polymerization between 20-60%, preferably 30-50%.

In a further variant of the present method, the protective layer to be applied to the printed side of the material plate is applied in an amount between 5 and 50 g / m ² , preferably 8 and 30 g / m ² , particularly preferably 10 and 20 g / m ² .

According to the invention, at least one wear layer is applied to the protective layer.

• Auftragen von mindestens einer ersten Harzschicht auf die mindestens eine Schutzschicht;
• gleichmäßiges Aufstreuen von abriebfesten Partikeln auf die erste Harzschicht;
• Trocknen der mit den abriebfesten Partikeln versehenen ersten Harzschicht in mindestens einer Trocknungsvorrichtung;
• Auftragen von mindestens einer weiteren Harzschicht auf die getrocknete mit den abriebfesten Partikeln versehene erste Harzschicht, und
• Trocknen der weiteren Harzschicht.

The wear layer to be applied comprises a plurality, preferably at least two or three, resin layers which may contain wear-inhibiting particles. The multi-layer wear protection layer can be applied by the following steps:

• Applying at least one first resin layer to the at least one protective layer;
• uniform spreading of abrasion-resistant particles on the first resin layer;
• Drying the first resin layer provided with the abrasion-resistant particles in at least one drying device;
• Applying at least one further resin layer to the dried first abrasion resistant particles provided with the first resin layer, and
• Dry the other resin layer.

The amount of the first resin layer applied may be between 20-100 g / m ² , preferably 30-80 g / m ² , particularly preferably 30-70 g / m ² . The solid content of the resin used for the first resin layer is 50-70% by weight, preferably 50-60% by weight, particularly preferably 55% by weight.

The abrasion-resistant particles used to increase the wear resistance preferably comprise corundum (aluminum oxides), boron carbides, silicon dioxides, silicon carbides, the use of corundum being particularly preferred. In one embodiment, the amount of abrasion-resistant particles scattered on the first resin layer is 10 to 50 g / m ² , preferably 10 to 30 g / m ² , particularly preferably 15 to 25 g / m ² .

The amount of the further second resin layer applied to the protective layer may be between 10-50 g / m ² , preferably 20-30 g / m ² , particularly preferably 25 g / m ² . The solid content of the resin used for the second resin layer is 50-70% by weight, preferably 50-60% by weight, particularly preferably 55% by weight. This second resin layer can also be omitted.

In a further embodiment of the present method, at least a third resin layer is applied to the top and bottom of the wood-based panel, i. applied to the respective second (dried) resin layer.

The amount of the applied third resin layer may be between 10-40 g / m ² , preferably 15-30 g / m ² , particularly preferably 20 g / m ² , the solids content being between 50-80% by weight, preferably 60-70% by weight. , particularly preferably 60-65% by weight, for example at 61.5% by weight.

In a variant, the resin to be applied as the third resin layer may contain glass spheres, the glass spheres preferably acting as spacers. The glass beads preferably used have a diameter of 50-100 microns, preferably from 60-80 microns. The application amount of the glass beads, when applied together with the third resin layer, is 1-5 g / m ² , preferably 2-4 g / m ² , particularly preferably 3 g / m ² .

In a further variant, the glass beads can be sprinkled onto the applied third resin layer. In this case, ie, when the glass beads are scattered, the application amount of the glass beads is 5-10 g / m ² , preferably 6-8 g / m ² , particularly preferably 6 g / m ² .

Following the drying process for the third resin layer, it is optionally possible to apply at least a fourth resin layer to the third resin layer.

The amount of coated on the fourth resin layer may be between 10-40 g / m ² , preferably 15-30 g / m ² , particularly preferably 20 g / m ² at a solids content of 50-80% by weight, preferably 60-70% by weight, particularly preferably 60-65% by weight, for example 61.6% by weight.

In a further variant of the present method, the resin to be applied as the fourth resin layer may contain glass beads and / or fibers, in particular cellulose fibers. In the case of adding glass beads to the resin to be applied, the application amount of glass beads is 1-5 g / m ² , preferably 2-4 g / m ² , particularly preferably 3 g / m ² . The application amount of the fibers, such as cellulose fibers, when applied together with the fourth resin layer, is between 0.1-0.5 g / m ² , preferably 0.2-0.4 g / m ² , particularly preferably 0 , 25 g / m ² . The addition of glass beads and / or fibers such as cellulose fibers to the top fourth layer contributes to the wear resistance of the material board.

It is also possible and provided that the underside of the material plate is also provided with one or more resin layers. In this case, the resin layers on the underside of the material plate contain no anti-wear particles such as corundum or glass beads and no cellulose fibers.

The resin layers are preferably (in approximately equal amounts) applied in parallel or simultaneously on the top and bottom of the material plate in at least one double application device (roller application unit).

The resin layer (s) applied on the underside of the material plate act in return. By applying the resin layers on the top and bottom of the material plates in approximately the same amounts, it is ensured that the tensile forces on the material plate arising from the applied layers during subsequent compression cancel each other out. In the layer structure and the respective layer thickness, the counter-coating applied to the underside corresponds approximately to the layer sequence applied on the upper side with the difference between the abrasion-resistant particles and glass spheres.

The amount of the first resin layer applied to the underside of the wood-based panel may be between 50-100 g / m ² , preferably 60-80 g / m ² , particularly preferably 60 g / m ² . Preferably, the first lower resin layer (eg, brownish) is colored to simulate a paper backing.

The amount of a second resin layer applied to the underside of the wood-based panel may be between 30-80 g / m ² , preferably 40-60 g / m ² , particularly preferably 50 g / m ² .

The amount of a third resin layer applied to the underside of the wood-based panel may be between 20-70 g / m ² , preferably 30-50 g / m ² , particularly preferably 40 g / m ² at a solids content of 50-70% by weight, preferably 50-70% by weight. 60% by weight, particularly preferably 55% by weight.

The amount of a fourth resin layer applied to the underside of the wood-based panel may be between 10-60 g / m ² , preferably 20-50 g / m ² , particularly preferably 30 g / m ² at a solids content of 50-70% by weight, preferably 50-70% by weight. 60% by weight, particularly preferably 55% by weight.

It should also be noted that it is possible to add further additives, such as hardeners, wetting agents, defoamers and / or release agents, to all resin layers.

The final resin layer applied to the top and bottom of the material plate, e.g. a fourth resin layer is finally dried in at least one further drying device. The drying of the respective resin layers is preferably carried out to a residual moisture of 6-9 wt%, e.g. in a circulating air dryer.

In the pressing step following the last drying step, the layer structure is compressed under pressure and temperature in a short-cycle press at temperatures between 150 and 250 ° C., preferably between 180 and 230 ° C., particularly preferably at 200 ° C. and a pressure between 100 and 1000 N / cm ² , preferably 200 and 700 N / cm ² , particularly preferably between 250 and 600 N / cm ² .

The present method thus allows the production of a printed material plate with the following layer structure: material plate, at least one applied directly to the top of the material plate decorative layer, wherein the at least one decorative layer comprises at least one additive in the form of gas-filled microspheres; and at least one at least dried protective layer.

In a first preferred embodiment, the printed material plate has the following layer structure: Material plate - resin layer (rolling ground) - primer layer (s) - first decorative layer - second decorative layer with gas-filled microspheres - protective layer - wear layer (s). Each of these layers may be present in one or more layers. It is generally possible that e.g. multiple primer layers and a primer layer are present.

In a second preferred embodiment, the printed material plate has the following layer structure: Material plate - resin layer (rolling base) - primer layer (s) - primer layer - first Druckdekorschicht - second Druckdekorschicht with gas-filled microspheres - protective layer - first wear layer - second wear layer.

In a further embodiment, at least a third and fourth resin layer on the top and bottom of the wood-based panel are provided, wherein in the provided on the upper side of the wood material board third and fourth resin layer each glass beads and / or fibers, in particular cellulose fibers may be included.

In a preferred embodiment, the present method makes it possible to produce a printed material plate with the following layer structure (seen from the bottom upwards):
Backing of four resin layers - material plate - primer layer - first print decor layer - second print decor layer with gas filled microsphere protection layer - first resin layer - abrasion resistant particle layer - second resin layer - third resin layer with glass spheres - fourth resin layer with glass spheres and / or cellulose fibers.

The present method for producing a printed material plate is carried out in a production line which comprises at least one printing device for applying a printing decor layer containing the gas-filled microspheres, at least one application device for applying the protective layer and at least one drying device for drying the protective layer, wherein the at least one application device for the protective layer is arranged in the processing direction after the printing device.

For carrying out the present method, it is likewise advantageous if at least one grinding device for grinding the surface of the material plate is provided in the production line. The at least one grinding device is arranged in the processing direction in front of the printing device.

In a further variant, the present production line comprises a device for applying a resin layer (rolling base) to the preferably ground material plate and a device for drying the resin layer (for example in the form of a convection dryer), both devices being arranged behind the grinding machine in the processing direction.

In a further embodiment, the present production line comprises at least one device for applying a pigmented layer, such as a primer layer to a material plate and a device for drying the primer layer, such as a convection dryer, following this applicator device. Depending on requirements, more than one primer layer can be applied, so that more than one applicator for the primer layer, each with a subsequent convection dryer, can be provided in the production line. the number of Application devices for the primer layer with subsequent convection dryer is arbitrarily variable and easily adaptable to the given production conditions.

In a further embodiment variant of the present production line, the application device for the primer is followed by at least one application device for a primer layer followed by convection dryer followed by at least one application device, preferably two to three application devices for the decorative layers and at least one final application device for a protective layer including convection dryer.

The application devices for the various layers to be applied can be in the form of a roller, spray device or pouring device, and the drying devices respectively arranged downstream of the application devices can be in the form of a convection dryer, IR and / or NIR drier.

The application device for the decorative layers may comprise at least one pressure roller and / or at least one digital printer, wherein in the case of a digital printer, a digital printer with 1 to n single color printheads or 1 to n multi color printheads can be used.

1. a) mindestens eine Schleifmaschine zum Schleifen der Oberfläche der Werkstoffplatte und mindestens ein in Verarbeitungsrichtung hinter der Schleifmaschine angeordnetes IR-Aggregat (wobei das IR-Aggregat insbesondere eine Erzeugung einer vorbestimmten Mindestoberflächentemperatur und Vergleichmäßigung der Oberflächentemperatur dient);
2. b) eine erste Auftragsvorrichtung zum Auftragen von mindestens einer ersten Harzschicht (Walzgrund) auf die (geschliffene) Werkstoffplatte;
3. c) eine in einer Verarbeitungsrichtung hinter der ersten Auftragsvorrichtung angeordnete erste Trocknungsvorrichtung (z.B. Konvektionstrockner) zum Trocknen der mindestens einen ersten Harzschicht (Walzgrund);
4. d) eine in Verarbeitungsrichtung hinter der ersten Auftragsvorrichtung angeordnete zweite Auftragsvorrichtung zum Auftragen von mindestens einer Grundierungsschicht auf die Werkstoffplatte, wobei die zweite Auftragsvorrichtung mindestens eine, bevorzugt zwei, insbesondere bevorzugt vier Auftragswerke umfasst;
5. e) eine in Verarbeitungsrichtung hinter der zweiten Auftragsvorrichtung angeordnete zweite Trocknungsvorrichtung (z.B. Konvektionstrockner) zum Trocknen der mindestens einen Grundierungsschicht;
6. f) eine in Verarbeitungsrichtung hinter der zweiten Trocknungsvorrichtung zum Trocknen der mindestens einen Grundierungsschicht angeordnete dritte Auftragsvorrichtung zum Auftragen von mindestens einer Primerschicht auf die Werkstoffplatte;
7. g) eine in Verarbeitungsrichtung hinter der dritten Auftragsvorrichtung angeordnete dritte Trocknungsvorrichtung (z.B. Konvektionstrockner) zum Trocknen der mindestens einen Primerschicht;
8. h) eine in Verarbeitungsrichtung hinter der dritten Trocknungsvorrichtung zum Trocknen der Primerschicht angeordnete vierte Auftragsvorrichtung zum Auftragen von mindestens einer Dekorschicht, wobei die vierte Auftragsvorrichtung mehrere Druckwalzen zum Tiefdruck (z.B. Drei- oder Vierdruckwalzen) und/oder einen Digitaldrucker umfassen kann;
9. i) eine in Verarbeitungsrichtung hinter der vierten Auftragsvorrichtung zum Auftragen der Dekorschicht angeordnete fünfte Auftragsvorrichtung zum Auftragen von mindestens einer Schutzschicht; und
10. j) eine in Verarbeitungsrichtung hinter der fünften Auftragsvorrichtung zum Auftragen der mindestens einen Schutzschicht angeordnete vierte Trocknungsvorrichtung (z.B. Konvektionstrockner) zum Antrocknen der mindestens einen Schutzschicht.

In a preferred embodiment, the construction of a (first) production line until the application of the protective layer in a first production section is as follows:

1. a) at least one grinding machine for grinding the surface of the material plate and at least one downstream in the processing direction of the grinder arranged IR-aggregate (the IR-aggregate is in particular a generation of a predetermined minimum surface temperature and equalization of the surface temperature);
2. b) a first application device for applying at least a first resin layer (rolling ground) to the (ground) material plate;
3. c) a first drying device arranged downstream of the first application device in a processing direction (eg convection dryer) for drying the at least one first resin layer (rolling ground);
4. d) a second application device arranged behind the first application device in the processing direction for applying at least one primer layer to the material plate, the second applicator device comprising at least one, preferably two, particularly preferably four, applicators;
5. e) a second drying device arranged downstream of the second application device in the processing direction (eg convection dryer) for drying the at least one primer layer;
6. f) a third application device arranged in the processing direction behind the second drying device for drying the at least one primer layer, for applying at least one primer layer to the material plate;
7. g) a third drying device arranged downstream of the third application device in the processing direction (eg convection dryer) for drying the at least one primer layer;
8. h) a downstream in the processing direction downstream of the third drying device for drying the primer layer fourth application device for applying at least one decorative layer, wherein the fourth application device may comprise a plurality of gravure printing rollers (eg three or four-pressure rollers) and / or a digital printer;
9. i) a fifth application device arranged behind the fourth application device for applying the decorative layer in the processing direction for applying at least one protective layer; and
10. j) a downstream in the processing direction behind the fifth application device for applying the at least one protective layer arranged fourth drying device (eg convection dryer) for drying the at least one protective layer.

The provided with the dried protective layer and printed material plates can either be stored temporarily or immediately further processing, in particular for applying the wear protection layer, a further (second) production line in a second production section are supplied.

• mindestens eine erste Auftragsvorrichtung zum Auftragen einer ersten Harzschicht auf die Oberseite und/oder Unterseite der Werkstoffplatte,
• mindestens eine in Verarbeitungsrichtung hinter der ersten Auftragsvorrichtung angeordnete Vorrichtung zum Aufstreuen einer vorbestimmten Menge an abriebfesten Partikeln;
• mindestens eine in Verarbeitungsrichtung hinter der ersten Auftragsvorrichtung und Streuvorrichtung angeordnete erste Trocknungsvorrichtung zum Trocknen der ersten oberen und/oder unteren Harzschicht;
• mindestens eine in Verarbeitungsrichtung hinter der ersten Trocknungsvorrichtung angeordnete zweite Auftragsvorrichtung zum Auftragen einer zweiten Harzschicht auf die Oberseite und/oder Unterseite der Werkstoffplatte,
• mindestens eine in Verarbeitungsrichtung hinter der zweiten Auftragsvorrichtung angeordnete zweite Trocknungsvorrichtung zum Trocknen der zweiten oberen und/oder unteren Harzschicht; und
• mindestens eine Pressvorrichtung, insbesondere eine Kurztaktpresse, zum Verpressen des Schichtaufbaus.

The second production line for carrying out the order of the wear protection layer in a second production section further comprises the following elements:

• at least one first application device for applying a first resin layer to the top side and / or bottom side of the material plate,
• at least one downstream of the first applicator device arranged in the processing direction for spreading a predetermined amount of abrasion-resistant particles;
• at least one first drying device arranged behind the first application device and scattering device in the processing direction for drying the first upper and / or lower resin layer;
• at least one downstream in the processing direction behind the first drying device arranged second application device for applying a second resin layer on the top and / or bottom of the material plate,
• at least one second drying device arranged behind the second application device in the processing direction for drying the second upper and / or lower resin layer; and
• at least one pressing device, in particular a short-cycle press, for pressing the layer structure.

• mindestens eine in Verarbeitungsrichtung hinter der zweiten Trocknungsvorrichtung angeordnete dritte Auftragsvorrichtung zum Auftragen einer dritten Harzschicht auf die Oberseite, die zum Beispiel Glaskugeln enthalten kann, und/oder Unterseite der Werkstoffplatte (ohne Glaskugeln),
• mindestens eine in Verarbeitungsrichtung hinter der dritten Auftragsvorrichtung angeordnete dritte Trocknungsvorrichtung zum Trocknen der dritten oberen und unteren Harzschicht;
• mindestens eine in Verarbeitungsrichtung hinter der dritten Trocknungsvorrichtung angeordnete vierte Auftragsvorrichtung zum Auftragen einer vierten Harzschicht, die zum Beispiel Glaspartikel bzw. Glaskugeln und/oder Fasern enthalten kann, auf die Oberseite und/oder Unterseite der Werkstoffplatte (ohne Glaskugeln oder Fasern);
• mindestens eine in Verarbeitungsrichtung hinter der vierten Auftragsvorrichtung angeordnete vierten Trocknungsvorrichtung zum Trocknen der vierten oberen und unteren Harzschicht; und
• mindestens eine in Verarbeitungsrichtung hinter der vierten Trocknungsvorrichtung angeordnete Kurztaktpresse.

In a preferred embodiment, the second production line for carrying out the present method in the second production section further comprises

• at least one third application device arranged behind the second drying device in the processing direction for applying a third resin layer to the upper side, which may contain glass spheres, for example, and / or underside of the material plate (without glass spheres),
• at least one third drying device arranged behind the third application device in the processing direction for drying the third upper and lower resin layer;
• at least one downstream in the processing direction downstream of the third drying device arranged fourth application device for applying a fourth resin layer, which may contain, for example, glass particles or glass beads and / or fibers on the top and / or bottom of the material plate (without glass beads or fibers);
• at least one fourth drying device arranged after the fourth application device in the processing direction for drying the fourth upper and lower resin layers; and
• at least one short-cycle press arranged in the processing direction behind the fourth drying device.

The spreader or scattering device is therefore installed in a production line in which aqueous resins can be applied to primed and printed plates via several roller applicators. At the beginning of the process, a resin coating is applied to individual plates, into which the abrasion-resistant material such as corundum is then sprinkled with the spreader.

The spreader provided in the present (second) production line is suitable for spreading powder, granules, fibers and comprises an oscillating brush system. The spreader consists essentially of a storage hopper, a rotating, structured roller and a scraper. In this case, the order quantity of abrasion-resistant material is determined by the rotational speed of the roller.

In one embodiment of the present second production line it is additionally provided that the at least one scattering device is surrounded by at least one cabin provided with at least one means for removing dusts occurring in the cabin. The means for removing the dust may be in the form of a suction device or as a device for blowing in air. The injection of air can be achieved through nozzles installed at the disc inlet and outlet, which inject air into the cabin. In addition, these can prevent air movements from creating an inhomogeneous curtain of abrasion-resistant material.

The removal of the dust from abrasion-resistant material from the environment of the spreader is advantageous because in addition to the apparent health burden for working on the production line workers of particulate matter from abrasion-resistant particles deposits on other parts of the production line and leads to increased wear of the same. The arrangement of the scattering device in a cabin therefore not only serves to reduce the health dust load of the environment of the production line but also prevents premature wear.

The scattering device is preferably controlled by a light barrier, the light barrier being arranged in the processing direction in front of the roller (scattering roller) provided below the scattering device. The control of the scattering device by a light barrier makes sense that between the individual wood-based panels more or less large gaps are, This starts the scattering process as soon as a plate is in front of the scattering roller.

In one embodiment of the present scattering device, at least one funnel for collecting excess abrasion-resistant particles (ie not scattered on the at least one wood-based panel, but rather before the retraction of the wood-based panel by means of the transport device under the scattering roller before derselbigen falling-down abrasion-resistant particles) is provided in front of the scattering roller ,

In a further variant, the hopper is coupled to at least one conveyor and a screening device, wherein the collected in the hopper excess abrasion resistant material is transported via the conveyor to the screening device. The screen meshes of the screening device correspond to the largest grain used of the abrasion resistant particulate material (i.e., about 80-100 μm). In the sifter, debris and clumped material (such as clumped resin or clumped abrasion resistant material) is separated from the collected abrasion resistant material, and the sieved abrasion resistant material can be recycled to the spreader.

Figur 1

eine schematische Darstellung einer ersten Fertigungslinie einer bedruckten Werkstoffplatte unter Anwendung des erfindungsgemäßen Verfahrens; und

Figur 2

eine schematische Darstellung einer weiteren, zweiten Fertigungslinie einer bedruckten Werkstoffplatte.

The invention will be explained in more detail with reference to the figures of the drawings of an embodiment. Show it:

FIG. 1

a schematic representation of a first production line of a printed material plate using the method according to the invention; and

FIG. 2

a schematic representation of another, second production line of a printed material plate.

First production line of FIG. 1

At the printing plant, HDF boards are processed. First, the HDF raw plates are singulated and the surface of the HDF plate is ground in a grinding machine 1. To For grinding, the plates are preheated in an IR dryer 2 to a temperature of about 45 ° C.

This is followed by a first application of resin (rolling base) in the first coater 3 with subsequent drying by hot air in a convection dryer 4. The coating resin used is an aqueous melamine-formaldehyde resin having a solids content of 60% by weight.

Then, a water-based white primer based on casein and inorganic pigments is applied by means of four application units 5 and dried by hot air after each application in a convection dryer 6. The individual commissioned works 5 apply different amounts of primer. The total white application varies depending on the pressure requirement between 20 g / m ² and 30 g / m ² .

This is followed by a primer application 7 followed by drying in a further convection dryer 8. This is followed by printing 9 (decoration) of the plates in indirect gravure printing. Here, a decorative layer is first printed with colored pigments followed by a further decorative layer, which has the gas-filled microspheres.

After printing, the plates are coated with melamine-formaldehyde resin 10 (protective layer) and also dried in a convection dryer 11. Then the plates are stored for a few days before being placed in a second production line ( FIG. 2 ) further processed.

The primer process is particularly important as it has a significant impact on the color print quality of the coated HDF plates. For a particular color pattern also a constant amount of white order must be guaranteed, otherwise it may come to different brightnesses of the primer and thus also to different colors within a color pattern over several plates.

Second Fertiaunaslinie of Figure 2

The in the FIG. 2 schematically illustrated second production line comprises four double application units 12, 13, 14, 15 for the simultaneous application of the respective resin layer on the top and the bottom of the separated printed material plates, for example printed HDF plates and four arranged in the processing direction behind the double application units convection dryer 12a, 13a, 14a, 15a.

After the first applicator roll 12, a first spreader 10 is also provided for uniformly spreading the abrasion resistant material such as e.g. Corundum provided on the first resin layer on top of the HDF board. The drying of the first resin layer then takes place in the first convection dryer 12a.

This is followed by a second double applicator 13 for applying a second resin layer and a second convection dryer 13a for drying the second resin layer.

The third double applicator 14 for applying the third resin layer may be followed by a further diffuser 20 for applying glass beads to the third resin layer, followed by a third convection dryer 14a for drying the third resin layer. The diffuser 20 for the glass beads is optional. The glass beads can also be applied together with the third resin layer.

After applying the fourth resin layer, which in the case of the fourth resin layer on the upper side, e.g. Cellulose fibers may contain, in a fourth double applicator 15 and drying in a fourth convection dryer 15 a, the layer structure is pressed in a short-cycle press 16. The pressed plates are cooled and stored.

Embodiment 1

1. a) Cleaning grinding: HDF boards in the dimensions of 2600 to 5600 mm in length, up to 2070 mm in width and between 5 and 15 mm in thickness are ground / cleaned in a Heesemann grinding machine (material removal <0.1 mm ). The press skin is not abraded in this process, but fixed by the subsequent melamine resin jobs.
2. b) Priming with melamine resin: 20-30 g melamine resin fl./m ^{2 are} applied with a roller. The solids content of the resin is about 55 wt.%. Subsequently, the primer is dried in a dryer. In all drying processes, only the solvent water is removed from the melamine resin. The reactivity of the melamine resin is essentially retained.
3. c) Application of pigmented primer: 5-6 g of pigmented primer / m ^{2 are} applied in a total of five roller applicators and dried after each application. The water-based primer contains titanium dioxide as pigment and casein or soy protein as binder.
4. d) Application Primer: A primer is applied to the dried, pigmented primer with a roller aggregate. It is the binder of the pigmented primer. The order quantity is 1 - 2 g fl./m ² .
5. e) Application Decor: A wood decor is applied to the primed and primed HDF by gravure printing. It is a three-color print, in which the pore structure is applied in the last printing unit. In a further printing unit, a pressure roller with the same structure as the pore roller is provided. With this pressure roller, a transparent printing ink is applied which, in addition to the binder (casein), also contains gas-filled microspheres (about 0.4% by weight). About 1 g / m ^{2 of} this printing ink is printed, whereby it was ensured by the repeat control that this printing ink is in the same areas as the pore color.
6. f) Application protective layer: A liquid melamine-formaldehyde resin layer is applied to the printed plate as a transport protection and dried. The order quantity is 15-25 g melamine resin / m ² . The solids content of the resin including possible glass beads is 60-70% by weight.
   The further processing takes place in the second production line according to the FIG. 2 instead of.
7. g) Application Wear protection: In the following production, melamine resin is first applied to the transport protection (30-50 g melamine resin fl./m ² , solids content melamine resin: 55% by weight). Corundum is then sprinkled onto the still moist melamine resin with a spreader. The spread rate is - depending on the required wear class - 15 - 30 g corundum / m ² . The corundum has a maximum grain size of about 90 microns. On the underside of the plate, a melamine resin is also applied by means of a roll applicator. The melamine resin may be colored and applied in the same amount as on the top. The solids content of the melamine resin is about 55% by weight. Subsequently, the resin layer is dried in a dryer.
   In the further production steps, further melamine resin containing cellulose and / or glass beads is applied to the corundum. The glass spheres have a diameter of up to 110μm. They serve as spacers between corundum and the press plate. In this case, an intermediate drying is interposed after each job. On the underside, melamine resin is also applied in the roller application units. In this case, the order amount on the top at the end of the resin application should reach similar amounts, as on the bottom.
8. h) After the last drying step, the coated plate is pressed in a KT press at high temperatures (190 - 210 ° C) and high pressures (200 - 600 N / cm ² ).

After pressing the plate, it was found that a degree of gloss difference from the surface had formed in the area of the structuring due to the expansion of the microspheres.

Embodiment 2:

On a primed and primed HDF according to the procedure described above, a wood decor was applied in digital printing. It was a four-color print (CMYK). The printing inks had water as solvent. In an additional set of printheads, a transparent ink was applied. This was coupled via the software to the black (K). The printing ink contained in addition to the solvent, glycol and the binder still microspheres (about 0.6% by weight). About 0.7 g / m ^{2 of} this printing ink was printed, whereby the coupling to the black ensured that this printing ink was in the same areas as the pore color.

Subsequently, the printed plate was further processed as in the above-described method. After pressing the plate, it was found that a degree of gloss difference from the surface had formed in the area of the structuring due to the expansion of the microspheres.

Claims (15)

1. A method for producing a material panel provided with a decorative layer comprising the following steps:

   - providing at least one material panel made of a wood-based material or a wood-based material-plastic mixture with an upper side and a lower side,

   - applying at least one resin layer and at least one base coat layer to the upper side of the material panel;

   - applying at least one decorative layer in direct print to the upper side of the at least one material panel, wherein the at least one decorative layer comprises at least one additive in the form of gas-filled microspheres;

   - applying at least one protective layer to the at least one decorative layer;

   - at least surface drying of said at least one protective layer, said method being

   characterized by the following steps:

   - applying at least one wear-resistant layer to the protective layer, the wear-resistant layer being applied by the following steps:

   - applying at least one first resin layer to said at least one protective layer;

   - uniformly spreading abrasion resistant particles on said first resin layer;

   - drying the first resin layer provided with the abrasion-resistant particles in at least one drying device;

   - applying at least one further resin layer to the dried first resin layer provided with the abrasion-resistant particles; and

   - drying of the further resin layer; and

   - pressing the layered structure in a short-cycle press at temperatures between 150 and 250°C and a pressure between 100 and 1000 N/cm², whereby the gas-filled microspheres expand.
2. Method according to claim 1, characterized in that a chipboard, medium density fibre (MDF), high density fibre (HDF) or coarse chipboard (OSB) or plywood panel is used as the material panel.
3. Method according to one of the preceding claims, characterized in that at least the upper side of the at least one material panel is subjected to at least one sanding operation before printing.
4. Method according to one of the preceding claims, characterized in that at least one primer layer is applied to the upper side of the material panel.
5. Method according to one of the preceding claims, characterized in that the at least one decorative layer is applied by gravure printing or digital printing.
6. Method according to at least one of the preceding claims, characterized in that the gas-filled microspheres are contained in the at least one decorative layer in an amount between 0.1 and 50 wt.%, preferably between 0.5 and 30 wt.%, in particular preferably between 1.0 and 10 wt.%.
7. Method according to one of the preceding claims, characterized in that the gas-filled microspheres consist of plastic spheres filled with a propellant gas.
8. Method according to one of the preceding claims, characterized in that the at least one decorative layer is applied in an amount between 0.1 and 10 g/m², preferably between 0.5 and 5 g/m², in particular preferably between 0.7 and 1 g/m².
9. Method according to one of the preceding claims, characterized in that more than one decorative layer is applied in direct printing.
10. Method according to one of the preceding claims, characterized in that the at least one protective layer contains an aqueous resin.
11. Method according to one of the preceding claims, characterized in that the amount of the first resin layer applied in the wear-resistant layer is between 20-100 g/m², preferably 30-80 g/m², more preferably 30-70 g/m², the solids content of the resin used for the first resin layer being 50-70 wt%, preferably 50-60 wt%, more preferably 55 wt%.
12. Method according to one of the preceding claims, characterized in that a second, third and fourth resin layer is applied to the first resin layer in the multi-layer wear-resistant layer.
13. Method according to claim 12, characterized in that the second resin layer is applied in an amount between 10-50 g/m², preferably 20-30 g/m², in particular preferably 25 g/m², the solids content of the resin used for the second resin layer being 50-70 wt%, preferably 50-60 wt%, in particular preferably 55 wt%.
14. Method according to claim 12 or 13, characterized in that the resin to be applied as a third resin layer contains glass beads in an amount of 1-5 g/m².
15. Method according to claim 12 or 13, characterized in that the resin to be applied as a fourth resin layer contains glass beads in an amount of 1-5 g/m².

Images