ES2770615T3 - Procedure for the manufacture of a board of material provided with a decorative layer - Google Patents

Abstract

Procedure for the manufacture of a material board provided with a decorative layer, which comprises the following steps: - provision of at least one material board made of a material derived from wood or a mixture of material derived from wood-plastic with an upper face and a lower face; - application of at least one layer of resin and at least one layer of primer on the upper face of the material board; - application of decorative layers in direct printing on the upper face of the at least one material board, at least one decorative layer comprising at least one additive in the form of gas-filled microspheres; the decorative layers being applied in a combination of gravure process and digital printing process; - application of at least one protective layer on the decorative layers; - at least beginning of drying of the at least one protection layer, the process being characterized by the following steps: - application of at least one wear protection layer on the protection layer, applying the wear protection layer with the following steps: - application of at least a first layer of resin on the at least one protective layer; - uniform spreading of abrasion resistant particles on the first resin layer; - drying of the first resin layer provided with the abrasion resistant particles in at least one drying device; - application of at least one other layer of resin on the first layer of dried resin, provided with the abrasion resistant particles; and - drying of the additional resin layer; and - pressing the layer structure in a short cycle press at temperatures between 150 and 250 ° C and a pressure of between 100 and 1000 N / cm2, expanding the gas-filled microspheres.

Description

DESCRIPTION

Procedure for the manufacture of a material board provided with a decorative layer

The present invention relates to a process for the manufacture of a board made of material provided with a decorative layer according to claim 1.

Description

Decorated wood-derived boards are frequently used for the manufacture of laminates for floors or in the form of wall and ceiling cladding elements.

There are several options for decorating wood-derived boards of this type. There is the possibility of covering boards of material derived from wood with a decorative paper, there being no limits to the diversity of decorative papers with different designs. As an alternative to the use of decorative papers on boards made from wood, the possibility of direct printing on boards made from wood has been increasingly developed, eliminating a paper print and subsequent lamination or direct coating. of the boards of matter derived from wood. The printing techniques used mostly for direct printing are the intaglio printing process and the digital printing process.

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

In the state of the art, two types of three-dimensional surface structures are known: the synchronous structure (or also of synchronous decoration) and the asynchronous structure.

A synchronous surface structure reflects individual elements of the printed decoration, the surface structures being made to a large extent congruent with the decoration. In the case of wooden decorations, the structures can be in the form of porous structures that follow the grain of the wood. In the case of tile decorations, the structures may be concavities in the area of joint covering lines included in the decoration.

Unlike the synchronous surface structure, an asynchronous surface structure forms a pattern that is distinguishable from printed decoration.

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

In the case of manufacturing a three-dimensional synchronous surface structure on a material board, a positioning of the pressing plate is necessary on the printed surface of the material board to ensure an alignment between the decoration and the surface structure of the pressing plate. This positioning requires complex and correspondingly expensive devices. After the structured press plate has been aligned with the impression, the pressing process is carried out with appropriate pressures and temperatures. The resulting three-dimensional synchronous surface structure reflects the surface of the pressing plate or the pressing plate.

In the case of an asynchronous surface structure, an exact alignment of the pressing plate and the printed layer on the wood-derived board is not important. The result is that in asynchronous surface structures there are optical differences between the printed decoration, such as wood grain, and the realized three-dimensional structures. Asynchronous surface structures are often used in lower quality laminate products for mass production.

Known processes for the manufacture of three-dimensional surface structures on boards made of wood-derived material therefore require pressing plates with different three-dimensional surface structures. The structuring of the pressing plates is carried out in acid etching processes in which the pressing plates are provided, for example, with a wooden pore or with a relief structure. By means of complex measures, a difference in the degree of gloss between the pore and the other areas can also be achieved in the structuring and subsequent chrome plating of the plate to also press a difference in the degree of gloss.

Ultimately this means that for each desired surface structure a corresponding press plate must be manufactured. Any change in the final surface structure requires the provision of a plate to press with a corresponding surface structure and a change of the plate to press in the press, which requires an interruption of the manufacturing process. Therefore, in particular the realization of synchronous surface structures in material boards is associated with considerable costs.

Document EP 1053382 B1 discloses a process for the manufacture of a door provided with a decoration, the decoration simulating a three-dimensional structure. For this purpose, several primer layers, decorative layers and protective layers are applied to a suitable substrate, such as MDF fibreboard. Components containing acrylic groups or vinyl-acrylic copolymers are used as primer layers. The printing ink used for the wood decoration pattern may be a so-called puffy ink which expands after heat treatment. This expanding ink can give the appearance of a three-dimensional structure to the decoration. However, in this case there is no pressing in a short cycle press under the action of pressure.

Therefore, the present invention has the technical objective of making available optical surface structures on material boards or backing boards by a method that can dispense with the use of structured press plates. In this case, the optical surface structures must be generated exclusively by the difference in the degree of gloss. The process must also allow other decorative effects as well. The stated objective is achieved according to the present invention by means of a method with the characteristics of claim 1.

Consequently, a process is made available for the manufacture of a material board provided with a decorative layer comprising the following steps:

- provision of at least one board made of a material derived from wood or a mixture of material derived from wood-plastic with an upper face and a lower face;

- application of at least one layer of resin and at least one layer of primer on the upper face of the material board;

- application of decorative layers in direct printing on the upper face of the at least one material board comprising at least one decorative layer at least one additive in the form of gas-filled microspheres; the decorative layers being applied in a combination of gravure process and digital printing process;

- application of at least one protective layer on the decorative layers;

- at least beginning of drying of the at least one protective layer; the procedure being characterized by the following stages:

- application of at least one wear protection layer on the protection layer, applying the wear protection layer with the following steps:

- application of at least a first layer of resin on the at least one protection layer;

- uniform spreading of abrasion resistant particles in the first resin layer;

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

- application of at least one other layer of resin on the first dried resin layer, provided with the abrasion resistant particles; and

- drying of the other 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 / cm2, expanding the gas-filled microspheres.

Correspondingly, a method is made available in which a structural optical effect is achieved by applying a decorative layer, using a printing ink with gas-filled microspheres as additive or aggregate.

This printing ink, which consists substantially of the binders commonly used in the printing process and an aggregate, generates a difference in the degree of gloss in the pore by means of the gas-filled microspheres during pressing.

As will be explained in more detail later, gravure and digital printing can be used as printing techniques for direct printing. In intaglio, printing ink is applied with a cylinder of pores. In digital printing, this ink is coupled by software with black (Key). Starting from a quantity set to black, the additional color is also printed in this case. Another possibility is to add the microspheres directly to the printing ink for the pore or black. Of course, the process can also start with a digital print on which the decoration is printed. A colorless ink with microspheres in the pore area is then printed with a printing cylinder. Alternatively, the ink may also contain coloring pigments.

In a preferable variant, a first decorative layer (without gas-filled microspheres) is first applied in gravure or digital printing, in which the decorative layer containing the gas-filled microspheres is in turn applied in gravure or digital printing. . Here different variations of the number of decorative layers with and without gas-filled microspheres are conceivable. Correspondingly, more than one decorative layer is applied in direct printing.

The gas-filled microspheres applied with the decorative layer expand at the high temperatures that occur in the final pressing stage. This expansion or this increase in the volume of the gas-filled microspheres leads to a change in the surface and an associated difference in the degree of gloss in the applied printed decoration, reflecting the optical differences, e.g. in the grain of a decorative grain.

The present process therefore makes it possible to provide an optically three-dimensional synchronous surface structure without the need to manufacture press plates or structured press plates. By using the same plate for pressing, different three-dimensional structures can be obtained in the final product, the structures being defined already in the printing stage by the gas-filled microspheres.

According to the invention, a support board made of a material derived from wood or a mixture of material derived from wood-plastic is used as a material board, in particular a chipboard, a medium density fibreboard (MDF ), high-density fibers (HDF) or oriented fibers (OSB) or a plywood.

In the case of a board made of material derived from wood as a support board, it has a maximum apparent density of 1400 kg / m3, preferably 1200 kg / m3, a minimum apparent density of 750 kg / m3, preferably 800 kg / m3, and an average apparent density of 850 kg / m3.

According to another embodiment of the present method, at least the upper face of the material board is subjected to at least one sanding process. During the sanding process a part of the surface of the material board is sanded, thereby improving the surface quality of the material board for the subsequent application of the decorative layer. The sanding process of the material board can be repeated as many times as desired.

In a next stage of the present process, at least one layer of resin is applied to the upper face, in particular to the sanded upper face of the material board. This resin layer is also called a laminate base layer and serves to improve the adhesion of the primer layer on the material board. The laminate base layer preferably comprises a formaldehyde resin, such as, for example, melamine-formaldehyde resin, melamine-urea-formaldehyde resin or urea-formaldehyde resin. This resin layer can be applied one or more times and can be made up of several layers accordingly. The resin layer (laminate base layer) is preferably dried after application, eg in a convection dryer.

According to the invention, at least one primer layer is applied in a subsequent step to the upper face of the material board, in particular to the at least one resin layer.

The primer layer preferably used in the present process comprises a casein composition as binder and inorganic pigments, in particular inorganic coloring pigments. White pigments such as titanium dioxide TiO2 can be used as coloring pigments. Other coloring pigments can be calcium carbonate, barium sulfate or barium carbonate. In addition to coloring pigments such as titanium dioxide and casein, the primer also contains water as a solvent.

It is also preferable that the applied pigmented primer layer is made up of at least one layer or application, preferably of at least two, especially preferably of at least four layers or applications applied in succession, the amount applied between the layers or applications may be the same or different, that is, the amount applied of each individual layer can vary. The applied amount of a layer or of an application of the primer layer can be between 1 and 50 g / m2, preferably between 2 and 30 g / m2, especially preferably between 5 and 15 g / m2 per board of material .

The total amount of the applied pigmented primer layer, in particular in the form of a liquid application, may be between 5 and 200 g / m2, preferably between 10 and 150 g / m2, especially preferably between 20 and 100 g / m2. m2 per material board.

After application of the primer layer, it is dried in at least one convection dryer. If several primer layers are applied, a corresponding step is carried out. drying after application of the corresponding primer coat. It is also conceivable that after each drying step of a primer layer, one or more sanding groups are provided for sanding the primer layers.

In the present case, in another embodiment, at least one primer layer can be applied on the upper face of the material board, preferably on the primer layer. The at least one primer layer is preferably formed by an aqueous plaster or a plaster that can be dried by ultraviolet radiation or electron beam. The applied amounts of the primer layer can be between 1 and 10 fl g / m2, preferably between 1 and 5 fl g / m2, especially preferably between 1 and 2 fl g / m2

The decorative layers are applied in a combination of a gravure process and a digital printing process. In the case of a printed decoration, a water-based pigmented printing ink can be applied in the intaglio process or in the digital printing process. This water-based pigmented printing ink can also be applied in more than one layer, for example two to ten layers, preferably three to eight layers.

The intaglio process is a printing technique in which the elements to be reproduced are presented as concavities in a printing form that is inked before printing. The printing ink is mainly found in the recesses and is transmitted by the pressure of the printing form and the adhesion forces to the object to be printed, such as a material board.

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

In digital printing, the printing image is transmitted directly from a computer to a printing machine, such as a laser printer or an ink jet printer. It is not necessary to use a static printer form. In both procedures it is possible to use aqueous paints and inks or coloring media based on ultraviolet radiation. Digital printing can be performed with 1 to n single-color print heads or 1 to n multi-color print heads (eg CYMK).

When using digital printing for the application of the decorative layer, the gas-filled microspheres can be contained in one or more inks or can also be applied separately. Digital impression can also be used as a single pass procedure or as a multiple pass procedure.

According to the invention the indicated printing techniques of intaglio and digital printing are combined. A suitable combination of printing techniques can be carried out on the one hand directly on the layer to be printed or also before printing by adapting the electronic data sets used. For example, a first decorative layer in gravure and other decorative layers in digital printing can be applied, or a first decorative layer in digital printing and other decorative layers can be applied in gravure.

In a preferred embodiment of the present process, the gas-filled microspheres are contained 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. weight, especially preferably between 1.0 and 10% by weight. Amounts between 0.4 and 5% by weight are especially preferable, in particular between 0.6 and 1% by weight for gas-filled microspheres.

Gas-filled microspheres are made up of plastic pellets filled with propellant gas. Suitable propellant gases are hydrocarbons in gas form, such as propane, n-butane, isobutane or pentane, but also carbon dioxide. The size or diameter of the gas-filled microspheres is between 1 and 200 pm, preferably between 2 and 150 pm, especially preferably between 5 and 100 pm, eg in a range of 10 to 30 pm.

It is also preferable that the decorative layers are applied in an amount between 0.1 and 10 g / m2, preferably between 0.5 and 5 g / m2, especially preferably between 0.7 and 1 g / m2.

In another embodiment, the second decorative layer containing the gas-filled microspheres has a transparent color. However, the second decorative layer containing the gas-filled microspheres can also have coloring pigments.

As already explained above, the printing ink used for the decorative layer can be applied in intaglio with a second printing cylinder (or pore cylinder) on the material board. The surface of the printing cylinder is structured and has micropores of different sizes to receive the printing ink. The printing ink is transmitted by the printing cylinder to the material board. Through proper control, such as eg by controlling the pattern repetition, it is ensured that the printing ink containing the gas-filled microspheres is in the same areas as the pore ink.

In the case of digital printing, the printing ink with the gas-filled microspheres is preferably coupled by software with the black (key). Here, from a certain amount of black, the additional printing ink is also printed. Another possibility is to add the microspheres directly to the printing ink for the pore or black. Of course, the process can also start with a digital printing, in which a first printing ink is printed as the first decorative layer. The second printing ink containing the gas-filled microspheres in the pore area is then printed with a printing cylinder. In another variant of the present method, provision can also be made for the decorative layers to comprise other additives to generate a mother-of-pearl or metal shine, sparkle effects, night luminescence or thermochromic effects.

As already mentioned above, a protective layer is provided in the decorative layers. This protective layer serves on the one hand as protection during transport and on the other hand as a mediator, as a so-called primer layer, between layers that are not already compatible, such as the decorative print or the decorative layer and a subsequent protection against wear other finishing coats.

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

Correspondingly, a resin, preferably a water-compatible resin, a varnish that can be dried by radiation, usually not compatible with water, can be applied directly in direct printing, eg chosen from the group of acrylates, modified acrylates and / or epoxides; or also polyurethanes that have good adhesion properties. Aqueous resins are particularly preferably used. After the beginning of the drying (as the beginning of the hardening or the beginning of the gelation) of the protective layer, an intermediate storage of the printed boards is possible without the risk of damaging the surface or the decorative layer getting dirty. Consequently, no problems are to be expected, such as the boards getting dirty or suffering from abrasion and / or detachment of the decoration, not even in the case of undefined time intervals between a machining stage of the decoration printing and another machining stage. Therefore, it is also ensured that printers do not have to interrupt their work in the event of a service interruption in post-processing.

In one embodiment, the protective layer to be applied to the decorative layers of the material board comprises at least one water-compatible resin, preferably a formaldehyde-containing resin, especially preferably melamine-formaldehyde resin, resin resin. urea-formaldehyde and / or melamine-urea-formaldehyde resin. Accordingly, the resin can be applied in a liquid form but also in a solid form, the use of a liquid resin being preferable.

The protective layer that acts as transport protection can also contain abrasion resistant particles such as corundum, glass spheres, cellulose fibers and other additives.

The protective layer comprising the at least one water-compatible resin is then dried or pre-dried until the resin is still flowable and can be crosslinked. The beginning of the drying of the protective layer containing a water-compatible resin is usually carried out in a continuous drying oven, as is known for the manufacture of boards made of material derived from wood. Depending on the amount applied, the pre-drying process can last from 5 to 15 seconds, preferably 5 to 10 seconds.

If a radiation-drying varnish is used as the protective layer, the onset of gelling of the protective layer following the application of the protective layer can be carried out using ultraviolet radiation (eg with 320-400 nm) , electron beam radiation and / or NIR radiation. After the onset of gelling, the varnish preferably has a degree of polymerization between 20 and 60%, preferably between 30 and 50%.

In another variant of the present method, the protection layer to be applied to the printed side of the material board is applied in an amount between 5 and 50 g / m2, preferably between 8 and 30 g / m2, especially preferably between 10 and 20 g / m2.

In a secondary variant of the present method, at least one wear protection layer is applied to the protection layer.

The wear protection layer to be applied comprises several layers of resin, preferably at least two or three, which may contain wear-reducing particles. The multi-layer wear protection layer can be applied in the following stages:

- application of at least a first layer of resin on the at least one protection layer;

- uniform spreading of abrasion resistant particles in the first resin layer;

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

- application of at least one other layer of resin on the first dried resin layer, provided with the abrasion resistant particles; and

- drying of the other layer of resin.

The amount of the first resin layer applied can be between 20 and 100 g / m2, preferably between 30 and 80 g / m2, especially preferably between 30 and 70 g / m2. The solids content of the resin used for the first resin layer is between 50 and 70% by weight, preferably between 50 and 60% by weight, especially preferably 55% by weight.

The abrasion resistant particles used to increase the wear resistance preferably comprise corundum (aluminum oxides), boron carbides, silicon dioxide, silicon carbides, the use of corundum being especially preferable. In one embodiment, the amount of abrasion resistant particles spread in the first resin layer is between 10 and 50 g / m2, preferably between 10 and 30 g / m2, especially preferably between 15 and 25 g / m2. m2.

The amount of the second resin layer applied in the protective layer can be between 10 and 50 g / m2, preferably between 20 and 30 g / m2, especially it can be 25 g / m2. The solids content of the resin used for the second resin layer is between 50 and 70% by weight, preferably between 50 and 60% by weight, especially preferably 55% by weight. This second layer of resin can also be dispensed with.

In another embodiment of the present method, at least a third layer of resin is applied respectively to the upper face and the lower face of the board made of material derived from wood, that is to say, to the resin layer which is respectively the second (dried ).

The amount of the third layer of resin applied can be between 10 and 40 g / m2, preferably between 15 and 30 g / m2, especially it can be 20 g / m2, the solids content being between 50 and 80% by weight, preferably between 60 and 70% by weight, especially preferably between 60 and 65% by weight, being, for example, 61.5% by weight.

In a variant, the resin to be applied as the third resin layer can contain glass spheres, the glass spheres preferably acting as spacers. The glass spheres used preferably have a diameter of 50 to 100 µm, preferably 60 to 80 µm. The applied amount of the glass spheres when they are applied together with the third resin layer is 1 to 5 g / m2, preferably 2 to 4 g / m2, especially 3 g / m2.

In another variant, the glass spheres can be spread on the third layer of applied resin. In this case, that is, when the glass spheres are spread, the applied amount of the glass spheres is 5 to 10 g / m2, preferably 6 to 8 g / m2, especially 6 g / m2.

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

The amount of the fourth layer of resin applied can be between 10 and 40 g / m2, preferably between 15 and 30 g / m2, especially it can be 20 g / m2 with a solids content between 50 and 80% by weight, preferably between 60 and 70% by weight, particularly preferably between 60 and 65% by weight, being, for example, 61.6% by weight.

In another variant of the present method, the resin to be applied as the fourth resin layer can contain glass spheres and / or fibers, in particular cellulose fibers. In case glass spheres are added to the resin to be applied, the applied amount of glass spheres is 1 to 5 g / m2, preferably 2 to 4 g / m2, especially preferably 3 g / m2. The applied amount of fibers, such as cellulose fibers, when these are applied together with the fourth layer of resin, is between 0.1 and 0.5 g / m2, preferably between 0.2 and 0, 4 g / m2, especially preferably 0.25 g / m2. The addition of glass spheres and / or fibers such as cellulose fibers to the fourth layer arranged above contributes to the wear resistance of the material board.

It is also possible and provided that the underside of the material board is also provided with one or more layers of resin. In this case, the resin layers on the underside of the material board do not contain abrasion reducing particles such as corundum or glass spheres or cellulose fibers.

The resin layers are preferably applied (in approximately equal amounts) in parallel or Simultaneously on the upper face and the lower face of the material panel in at least one double application device (application group with cylinder).

The resin layer (s) applied to the underside of the material board act (s) as countertraction. Thanks to the application of the resin layers on the upper face and the lower face of the material boards in approximately the same amounts, it is guaranteed that the tensile forces generated by the layers applied in the subsequent pressing and acting on the material board compensate each other. The countertraction applied on the lower face corresponds in terms of the layer structure and the corresponding thickness of the layers approximately to the sequence of layers applied on the upper face, with the difference of abrasion resistant particles and glass spheres.

The amount of the first layer of resin applied to the underside of the wood-derived material board may be between 50 and 100 g / m2, preferably between 60 and 80 g / m2, especially preferably 60 g / m2. m2. Preferably, the lower first resin layer is tinted (eg brown), to simulate a paper countertraction.

The amount of the second layer of resin applied to the underside of the wood-derived material board can be between 30 and 80 g / m2, preferably between 40 and 60 g / m2, especially preferably 50 g / m2. m2.

The amount of the third layer of resin applied to the underside of the wood-derived material board can be between 20 and 70 g / m2, preferably between 30 and 50 g / m2, especially preferably 40 g / m2. m2 with a solids content of between 50 and 70% by weight, preferably between 50 and 60% by weight, which is particularly preferably 55% by weight.

The amount of the fourth layer of resin applied to the underside of the wood-derived material board can be between 10 and 60 g / m2, preferably between 20 and 50 g / m2, especially preferably 30 g / m2. m2 with a solids content of between 50 and 70% by weight, preferably between 50 and 60% by weight, which is particularly preferably 55% by weight.

It should be added that other additives such as hardeners, cross-linkers, antifoams and / or anti-adhesion agents can be added to all the resin layers.

The final resin layer applied respectively to the upper face and the lower face of the material board, eg a fourth resin layer, is finally dried in at least one other drying device. Drying of the corresponding resin layers is preferably carried out to a residual humidity of between 6 and 9% by weight, eg in a circulating air dryer.

In the pressing stage that follows the last drying stage, the layer structure is pressed under the influence of pressure and temperature in a short-cycle press at temperatures between 150 and 250 ° C, preferably between 180 and 230 °. C, especially preferably at 200 ° C and a pressure between 100 and 1000 N / cm2, preferably between 200 and 700 N / cm2, especially preferably between 250 and 600 N / cm2.

The present procedure therefore allows the manufacture of a printed material board with the following layer structure:

board material - resin layer (laminate base layer) - primer layer (s) - first decorative layer - second decorative layer with gas-filled microspheres - protection layer - wear protection layer (s). Each of these layers can be presented in one or more layers. In general, it is possible, for example, for several primer layers and one primer layer to be present.

In a second preferred embodiment, the printed material board has the following layer structure: material board - resin layer (laminate base layer) - primer layer (s) - primer layer - first decorative layer - second decorative layer with gas-filled microspheres - protection layer - first wear protection layer - second wear protection layer.

In another embodiment, at least a third and fourth layer of resin are provided on the upper face and the lower face of the board made of material derived from wood, and may be contained in the third and fourth layer of resin provided on the upper face of the board made of material derived from wood, respectively glass spheres and / or fibers, in particular cellulose fibers. In this regard, in particular the third resin layer can be provided with glass spheres and the fourth with resin with glass spheres and / or cellulose fibers. A countertraction of four layers of resin can also be provided.

The present process for the manufacture of a printed material board is carried out in a manufacturing line that comprises at least one printing device for the application of a printed decorative layer containing the gas-filled microspheres, at least one application device for apply the protection layer and at least one drying device for starting to dry the protective layer, the at least one application device for the protective layer being arranged behind the printing device viewed in the machining direction.

To carry out the present method, it is also advantageous that at least one sanding device is provided in the manufacturing line to sand the surface of the material board. The at least one sanding device is arranged in front of the printing device when viewed in the machining direction.

In another variant, the present manufacturing line comprises a device for the application of a resin layer (laminate base layer) on the board of preferably sanded material and a device for drying the resin layer (for example, in in the form of a convection dryer), the two devices being arranged behind the sander when viewed in the machining direction.

In another embodiment, the present manufacturing line comprises at least one device for applying a pigmented layer, such as, for example, a primer layer on a board of material and a device arranged after this application device for drying the primer coat, such as a convection dryer. Depending on the need, more than one primer layer can be applied, so that more than one applicator device for the primer layer can be provided in the production line with respectively a convection dryer arranged downstream. The number of application devices for the primer layer with subsequent convection dryer can be freely chosen and can be easily adapted to the predetermined production conditions.

In another variant of embodiment of the present manufacturing line, after the application device for the primer there is arranged at least one application device for a primer layer with subsequent 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 protection layer including convection dryer.

The application devices for the different layers to be applied can be in the form of a cylinder, a spray device or a casting device, and the drying devices arranged respectively behind the application devices can be in the form of a convection dryer, a dryer infrared and / or a NIR (near infrared) dryer.

The application device for the decorative layers can comprise at least one printing cylinder and / or at least one digital printer, in the case of a digital printer a digital printer with 1 n one-color print heads or with 1 n can be used. multi-colored print heads.

In a preferred embodiment, the structure of a (first) manufacturing line up to the application of the protection layer in a first production run has the following appearance:

a) at least one sander to sand the surface of the material board and at least one infrared group arranged behind the sander seen in the machining direction (the infrared group in particular serving to generate a predetermined minimum surface temperature and to homogenize the temperature superficial);

b) a first application device for applying at least a first layer of resin (laminate base layer) on the material board (sanding);

c) a first drying device (eg convection dryer) arranged behind the first application device viewed in the machining direction to dry the at least one first resin layer (laminate base layer);

d) a second application device arranged behind the first application device seen in the machining direction for applying at least one primer layer on the material board, the second application device comprising at least one, preferably two, especially four enforcement mechanisms preferable;

e) a second drying device (eg convection dryer) arranged behind the second application device viewed in the machining direction to dry the at least one primer layer;

f) a third application device arranged behind the second drying device for drying the at least one primer layer viewed in the machining direction to apply at least one primer layer on the material board;

g) a third drying device (eg convection dryer) arranged behind the third application device viewed in the machining direction to dry the at least one primer layer;

h) a fourth application device arranged behind the third drying device for drying the primer layer viewed in the machining direction to apply at least one decorative layer, the fourth application device being able to comprise several printing cylinders for intaglio (p. eg triple or quadruple printing cylinders) and / or a digital printer;

i) a fifth application device arranged behind the fourth application device for applying the decorative layer viewed in the machining direction to apply at least one protective layer; and

j) a fourth drying device (eg convection dryer) arranged behind the fifth application device to apply the at least one protective layer viewed in the machining direction to start drying the at least one protective layer.

The boards of material printed and provided with the protection layer started to dry can be stored intermediate or can be fed immediately to other machining, in particular for the application of the protection layer against wear, to another (second) manufacturing line in a second section of production. The second manufacturing line to carry out the application of the wear protection layer in a second production section also comprises the following elements:

- at least one first application device for applying a first layer of resin on the upper face and / or lower face of the material board;

- at least one device arranged from the first application device seen in the machining direction to spread a predetermined quantity of abrasion resistant particles;

- at least one first drying device arranged behind the first application device and behind the spreading device seen in the machining direction to dry the upper and / or lower first resin layer;

- at least one second application device arranged behind the first drying device seen in the machining direction to apply a second layer of resin on the upper face and / or lower face of the material board;

- at least one second drying device arranged behind the second application device seen in the machining direction to dry 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. In a preferred embodiment, the second manufacturing line to carry out the present process in the second production stretch further comprises:

- at least one third application device arranged behind the second drying device seen in the machining direction to apply a third layer of resin on the upper face, which may contain for example glass spheres, and / or on the lower face of the material board (without glass spheres);

- at least one third drying device arranged behind the third application device viewed in the machining direction to dry the upper and lower third resin layer;

- at least a fourth application device arranged behind the third drying device seen in the machining direction to apply a fourth layer of resin, which can contain for example glass particles or glass spheres and / or fibers on the upper face and / or on the underside of the material board (without glass spheres or fibers);

- at least a fourth drying device arranged behind the fourth application device seen in the machining direction to dry the upper and lower fourth resin layer; and

- at least one short cycle press arranged behind the fourth drying device seen in the machining direction.

The spreading apparatus or spreading device is therefore installed in a manufacturing line in which aqueous resins can be applied by various cylinder application mechanisms on primed and printed boards. At the beginning of the process a strip of resin is applied on some boards, on which the abrasion resistant material such as corundum is subsequently spread with the spreading device.

The spreading device provided in the present (second) manufacturing line is suitable for spreading powder, granules, fibers and comprises a system of oscillating brushes. The spreading device is substantially formed by a feed hopper, a rotatable structured cylinder and a scraper. The cylinder turning speed depends on the applied amount of abrasion resistant material.

In an embodiment of the present second manufacturing line, it is further provided that the at least one spreading device is enclosed by at least one booth, which is provided with at least one means for removing powders that are produced in the booth or that be arranged inside it. The means for removing dust can be in the form of a suction device or else as a device for blowing in air. The blowing of air can be achieved by means of nozzles that are installed at the inlet and outlet of the boards and they blow air into the cabin. Furthermore, they can prevent an inhomogeneous spread curtain of abrasion resistant material from being formed by air movements.

The removal of abrasion resistant material dust from the environment of the spreading device is advantageous, since in addition to the obvious harm to the health of operators working on the production line, fine dust of abrasion resistant particles is also deposits in other parts of the production line installation and leads to increased wear on the production line. The arrangement of the spreading device in a booth therefore serves not only to reduce health damage from dust in the environment of the production line, but also to prevent premature wear.

The spreading device is preferably controlled by a light barrier, the light barrier being arranged in front of the cylinder (spreading cylinder) provided below the spreading device viewed in the machining direction. Controlling the spreading device by means of a light barrier is recommended, since there are more or less large gaps between the different boards made of material derived from wood. This starts the spreading process as soon as there is a board in front of the spreading cylinder.

In an embodiment of the present spreading device, at least one hopper is provided in front of the spreading cylinder to collect excess abrasion resistant particles (that is, abrasion resistant particles that do not spread on the at least one spreading board. material derived from wood, but on the contrary fall before the entrance of the board of material derived from wood with the help of the transport device below the spreading cylinder).

In another variant, the hopper is coupled with at least one transport device and a screening device, the excess abrasion resistant material collected in the hopper being transported by the transport device to the screening device. The sieving meshes of the sieving device correspond to the largest grain used of the abrasion resistant particulate material (ie approx. 80 to 100 µm). In the sieving device, dirt particles and agglomerated material (such as agglomerated resin or agglomerated abrasion resistant material) are separated from the collected abrasion resistant material and the sieved abrasion resistant material can be returned (recycled) in the sieving device. recreation.

In the following, the invention will be explained in more detail with reference to the figures of the drawings with an embodiment. They show:

Figure 1 a schematic representation of a first manufacturing line of a printed material board and

Figure 2 is a schematic representation of a second manufacturing line for a printed material board.

First manufacturing line of Figure 1

HDF boards are machined in the printing facility. First, the raw HDF boards are separated and the surface of the HDF board is sanded on a sander 1. After sanding, the boards are preheated in an infrared dryer 2 at a temperature of about 45 ° C.

Subsequently, a first resin application (laminate base layer) takes place in the first application mechanism 3 with subsequent drying by hot air in a convection dryer 4. An aqueous melamine-formaldehyde resin with a part of solids 60% by weight.

The white primer containing water based on casein and inorganic pigments is then applied using four application mechanisms 5 and dried after each application by hot air in a convection dryer 6. The different application mechanisms 5 apply different amounts of primer. The total white application varies depending on the printing requirements between 20 g / m2 and 30 g / m2.

This is followed by the application of a primer layer 7 with subsequent drying in another convection dryer 8. This is followed by the printing 9 (decoration) of the boards in indirect intaglio. Here, a decorative layer with coloring pigments is printed first, and then another decorative layer is printed with the gas-filled microspheres.

After printing, the boards are coated with melamine-formaldehyde resin 10 (protective layer) and are also started to dry in a convection dryer 11. The boards are then stored for a few days in between, before being continue machining in a second manufacturing line (Figure 2). The priming process is especially important, since it substantially influences the quality of the color printing of coated HDF boards. For a given color drawing, a quantity of white application must also be guaranteed as constant as possible, since if they cannot be presented different light intensities of the primer and therefore also different colors in a color pattern on several boards.

Second manufacturing line of Figure 2

The second manufacturing line represented schematically in Figure 2 comprises four double application groups 12, 13, 14, 15 to simultaneously apply the corresponding resin layer on the upper face and the lower face of the separate printed material boards, eg HDF printed boards as well as four convection dryers 12a, 13a, 14a, 15a arranged behind the dual application groups seen in the machining direction.

Behind the first application cylinder 12, a first spreading device 10 is further provided to spread evenly the wear-resistant material, such as corundum, in the first resin layer on the upper face of the HDF board. Drying of the first resin layer is subsequently carried out in the first convection dryer 12a.

Next, a second dual application mechanism 13 is arranged to apply a second layer of resin and a second convection dryer 13a to dry the second layer of resin.

Following the third dual application mechanism 14 to apply the third resin layer, another spreading device 20 may be arranged to apply glass spheres to the third resin layer, followed by a third convection dryer 14a to dry the third layer of resin. resin. The spreading device 20 for the glass spheres is optional. Glass spheres can also be applied together with the third layer of resin. After applying the fourth resin layer, which in the case of the fourth resin layer can contain e.g. cellulose fibers on the upper side in a fourth dual-application mechanism 15 and after drying in a fourth convection dryer 15a, the layer structure is pressed in a short cycle press 16. The pressed boards are cooled and stored.

The use of the aforementioned first and second manufacturing lines does not lead to the claimed process. Embodiment example 1 (not according to the invention)

a) Cleaning sanding: HDF boards measuring 2600 to 5600 mm long, 2070 wide and 5 to 15 mm thick are sanded / cleaned on a Heesemann sander (material reduction <0, 1 mm). The skin that results from pressing is not sanded in this process, but is fixed by subsequent applications of melamine resin.

b) Priming with melamine resin: 20 to 30 g of melamine resin are applied fl./m2 with a cylinder. The solids content of the resin is approximately 55% by weight. The primer is then dried in a dryer. In all drying processes, only the water solvent is removed from the melamine resin. The reactivity of the melamine resin is substantially maintained.

c) Application of the pigmented primer: In a total of five application mechanisms with a cylinder, 5 to 6 g of the pigmented primer are applied respectively per m2 and dried after each application. The water-based primer contains titanium dioxide as pigment and casein or soy protein as binder.

d) Application of the primer layer: In the dried pigmented primer a primer layer is applied with a cylinder group. It is the binder of the pigmented primer. The amount applied is located at 1 to 2 g fl./m2.

e) Application of the decoration: on the HDF board primed and provided with the primer layer, a wood decoration is applied in gravure. This is a three-color printing, in which the pore structure is applied in the last printing mechanism. In another printing device, an impression cylinder is made available with the identical structure to that of the pore cylinder. With this printing cylinder, a transparent printing ink is applied which, in addition to the binder (casein), also contains gas-filled microspheres (approx. 0.4% by weight). Approximately 1 g / m2 of this printing ink is printed, ensuring by controlling the repetition of the pattern that the printing ink is in the same areas as the pore ink.

f) Application of the protection layer: A layer of liquid melamine-formaldehyde resin is applied to the printed board as protection for transport and it begins to dry. The amount applied is 15 to 25 g of melamine resin / m2. The solids content of the resin including possible glass spheres is between 60 and 70% by weight.

Subsequent machining takes place on the second manufacturing line according to Figure 2.

g) Application of wear protection: In subsequent production, melamine resin is applied first in the transport protection (30 to 50 g of melamine resin fl./m2, solids content of melamine resin : 55% by weight). Corundum is then spread on the still wet melamine resin with a spreader. The amount spread is 15 to 30 g of corundum / m2, depending on the class of wear protection required. Corundum here has a maximum grain size of about 90 pm. A melamine resin is also applied to the underside of the board with the help of a cylinder application group. Melamine resin can be tinted and applied in the same amount as on the upper side. The solids content of the melamine resin is approximately 55% by weight. The resin layer is then dried in a dryer.

In the other production stages, another melamine resin containing cellulose and / or glass spheres is applied to the corundum. The glass spheres here have a diameter of up to 110 pm. They serve as spacers between the corundum and the pressing plate. After each application an intermediate drying is inserted. On the underside, melamine resin is also applied in the cylinder application groups. The amount applied on the upper side at the end of the resin application should reach similar amounts as on the lower side.

h) After the last drying stage, the coated board is pressed in a short cycle press at high temperatures (190 to 210 ° C) and high pressures (200 to 600 N / cm2).

After pressing the board, it was shown that a difference in the degree of gloss with respect to the surface had been generated in the area of the structuring due to the expansion of the microspheres.

Example of embodiment 2 (not according to the invention):

A wood decoration with digital printing was applied to an HDF board primed and provided with a primer layer according to the development of the procedure described above. It was a four-color (CMYK) print. The printing inks had water as a solvent. Transparent printing ink was applied to a further set of print heads. This was coupled by software with black (K). The printing ink also contained microspheres (approximately 0.6% by weight) in addition to the glycol solvent and the binder. About 0.7 g / m2 of this printing ink were printed, ensuring by coupling with the black that this printing ink was in the same areas as the pore ink. The printed board was then further machined as in the procedure described above. After pressing the board, it was shown that a difference in the degree of gloss with respect to the surface had been generated in the area of structuring due to the expansion of the microspheres.

Claims (15)

1. Procedure for the manufacture of a material board provided with a decorative layer, which comprises the following stages: - provision of at least one board made of a material derived from wood or a mixture of material derived from wood-plastic with an upper face and a lower face; - application of at least one layer of resin and at least one layer of primer on the upper face of the material board; - application of decorative layers in direct printing on the upper face of the at least one material board, at least one decorative layer comprising at least one additive in the form of gas-filled microspheres; the decorative layers being applied in a combination of gravure process and digital printing process; - application of at least one protective layer on the decorative layers; - at least beginning of drying of the at least one protection layer, the process being characterized by the following steps: - application of at least one wear protection layer over the protection layer, applying the wear protection layer with the following steps: - application of at least a first layer of resin on the at least one protective layer; - uniform spreading of abrasion resistant particles on the first resin layer; - drying of the first resin layer provided with the abrasion resistant particles in at least one drying device; - application of at least one other layer of resin on the first layer of dried resin, provided with the abrasion resistant particles; and - drying of the additional resin layer; and - pressing of the layer structure in a short cycle press at temperatures between 150 and 250 ° C and a pressure of between 100 and 1000 N / cm2, expanding the gas-filled microspheres. Method according to claim 1, characterized in that two to ten decorative layers of a pigmented water-based printing ink are applied in direct printing. Method according to one of the preceding claims, characterized in that the combination of intaglio and digital printing process takes place directly on the layer to be printed. Method according to one of the preceding claims, characterized in that a first decorative layer is applied in gravure and other decorative layers are applied in digital printing. Method according to one of Claims 1 to 3, characterized in that a first decorative layer is applied in digital printing and other decorative layers are applied in gravure. 6. Method according to claim 1, characterized in that the combination of intaglio and digital printing process takes place before printing by adapting the electronic data sets used. Method according to one of the preceding claims, characterized in that a first decorative layer without gas-filled microspheres is applied in the intaglio or digital printing process, onto which it is applied in the intaglio or digital printing process the decorative layer containing the gas-filled microspheres. 8. Method according to claim 7, characterized in that the second decorative layer containing the gas-filled microspheres has a transparent color. Method according to claim 7, characterized in that the second decorative layer containing the gas-filled microspheres has colored pigments. Method according to one of the preceding claims, characterized in that the gas-filled microspheres in the at least one decorative layer are contained in an amount of between 0.1 and 50% by weight, preferably between 0 5 to 30% by weight, especially preferably between 1.0 and 10% by weight. Method according to one of the preceding claims, characterized in that the layers Decorative items are applied in an amount of 0.1 to 10 g / m2, preferably 0.5 to 5 g / m2, especially preferably 0.7 to 1 g / m2. 12. Method according to one of the preceding claims, characterized in that the amount of the first resin layer applied to the wear protection layer is between 20 and 100 g / m2, preferably between 30 and 80 g / m2 , especially preferably between 30 and 70 g / m2, the solids content of the resin used for the first resin layer being between 50 and 70% by weight, preferably between 50 and 60% by weight, of especially preferably 55% by weight. Method according to one of the preceding claims, characterized in that a second, a third and a fourth resin layer is applied to the first resin layer in the multi-layer wear protection layer. 14. Process according to claim 13, characterized in that the second resin layer is applied in an amount of between 10 and 50 g / m2, preferably between 20 and 30 g / m2, especially preferably 25 g / m2. m2, the solids content of the resin used for the second resin layer being between 50 and 70% by weight, preferably between 50 and 60% by weight, especially preferably 55% by weight. 15. Process according to claims 13 or 14, characterized in that the resin to be applied as the third and fourth resin layers each contains glass spheres in an amount of 1 to 5 g / m2.