ES2730549T3 - Procedure for the manufacture of a material board provided with a decorative layer - Google Patents

Abstract

Procedure for the manufacture of a material board provided with a decorative layer, comprising the following steps: - making available at least one material board 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; - applying at least one decorative layer in direct printing on the upper face of the at least one board of material, the at least one decorative layer comprising at least one additive in the form of gas-filled microspheres; - application of at least one protection layer on the at least one decorative layer; - at least beginning of the drying of the at least one protective layer; the process being characterized by the following steps: - application of at least one wear protection layer on the protection layer, the wear protection layer being applied with the following steps: - application of at least a first resin layer on the at least one layer of protection; - uniform spread 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 resin layer on the first dried resin layer, provided with the 25 abrasion resistant particles; and - drying the additional resin layer; and - pressing the layer structure in a short cycle press at temperatures between 150 and 250 ºC and a pressure 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 manufacturing a material board provided with a decorative layer according to claim 1.

Description

The boards of wood-derived material provided with a decoration are frequently used for the manufacture of laminates for floors or in the form of wall and ceiling cladding elements.

For the decoration of boards of matter derived from wood of this type there are several options. There is the possibility of covering boards of material derived from wood with a decorative paper, there being no limits for the diversity of decorative papers of different drawings. As an alternative to the use of decorative papers on boards of wood-derived matter, the possibility of direct printing on boards of wood-derived matter has been increasingly developed, suppressing a paper print and subsequent plywood or direct coating of boards derived from wood. The printing techniques used primarily for direct printing are the gravure printing procedure and the digital printing procedure.

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 subsequent processing in the short cycle press, surface structures can also be generated on the surface using a structured pressing sheet.

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

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

Unlike the synchronous surface structure, an asynchronous surface structure forms a drawing that distinguishes itself from the 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 press plate is manufactured based on the printing data, for example, of a printing cylinder used for direct printing or of a digital printer.

In the case of manufacturing a three-dimensional synchronous surface structure on a material board, it is necessary to position the plate to be pressed on the printed surface of the material board to ensure an alignment between the decoration and the surface structure of the plate for pressing. This positioning requires complex and correspondingly expensive devices. After aligning the structured pressing plate with the printing, the pressing process is carried out with adequate 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 layer printed on the board of material derived from the wood does not matter. The result is that asynchronous surface structures produce optical differences between the printed decoration, such as a wood grain, and the three-dimensional structures made. Asynchronous surface structures are often used in lower quality laminate products for mass production.

Known processes for the manufacture of three-dimensional surface structures in boards of wood-derived matter 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 an embossed structure. Through complex measurements it can also be achieved in the structuring and subsequent chrome plating of the plate to also press a difference in the degree of brightness between the pore and the other areas.

Finally, this means that for each desired surface structure a corresponding pressing plate must be manufactured. Any change of 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 on material boards is linked to considerable costs.

From EP 1053382 B1 a process is known for the manufacture of a door provided with a decoration, the decoration simulating a three-dimensional structure. For this purpose they are applied on a suitable substrate, such as an MDF fiber board, several primer layers, decorative layers and protective layers. As primer layers, components containing acrylic groups or vinyl acrylic copolymers are used. The printing ink used for the wooden decoration drawing may be a so-called "puffy" ink that expands after a heat treatment. This expanding ink can confer 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 optical surface structures available on material boards or support boards by a method that can dispense with the use of structured pressing plates. Optical surface structures must be generated in this case exclusively by the difference in the degree of brightness. The procedure must also allow other decorative effects. The stated objective is achieved in accordance with the present invention by a method with the characteristics of claim 1.

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

- making available at least one material board 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 top face of the material board;

- application of at least one decorative layer in direct printing on the upper face of the at least one material board comprising the at least one decorative layer at least one additive in the form of gas-filled microspheres;

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

- at least beginning of drying of the at least one protective layer;

- 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 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 resin layer in the first dried resin layer, provided with 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 process is made available in which an optical structure effect is achieved by applying a decorative layer, using a printing ink with gas-filled microspheres as an additive or aggregate.

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

As will be explained later in greater detail, how gravure printing and digital printing can be used as printing techniques for direct printing. In rotogravure, printing ink is applied with a pore cylinder. In digital printing, this ink is coupled by software with black (Key). From a certain amount of 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. Next, a colorless ink with microspheres is printed with a printing cylinder in the area of the pores. Alternatively, the ink may also contain coloring pigments.

In a preferred variant, a first decorative layer (without gas-filled microspheres) in gravure or digital printing is applied first, in which the decorative layer containing the microspheres is applied full of gas in gravure or digital printing. Different variations of the number of decorative layers with and without gas-filled microspheres are conceivable here. Correspondingly, more than one decorative layer can be 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 a difference in the degree of brightness that is linked to it in the applied printed decoration, which reflects the optical differences, e.g. in the veining of a decorative veining.

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

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

In the case of a material board 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.

In accordance with another embodiment of the present process, 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, thus 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 step of the present invention, at least one resin layer is applied in accordance with the invention on the upper face, in particular on the sanded upper face of the material board. This resin layer is also called the base laminate 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 melamine formaldehyde resin, melamine urea formaldehyde resin or urea formaldehyde resin. This resin layer can be applied once or several times and can be correspondingly formed by several layers. The resin layer (laminate base layer) is preferably dried after application, eg in a convection dryer.

Furthermore, according to the process according to the invention, at least one primer layer is applied in a next step on the upper face of the material board, in particular in the at least one resin layer.

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

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

The total amount of the pigmented primer layer applied, 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 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 drying stage is carried out respectively after the application of the corresponding primer layer. It is also conceivable that after each stage of drying 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 top 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 by electronic beam. The applied quantities of the primer layer can be between 1 and 10 g fl / m2, preferably between 1 and 5 g fl / m2, especially preferably between 1 and 2 g fl / m2.

In another variant of the present process, the at least one decorative layer is applied in the gravure process or in the digital printing procedure. In the case of a printed decoration, a water-based pigmented printing ink can be applied in the gravure process or in the digital printing procedure. 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.

As already mentioned, the application of the at least one and optionally other decorative layers is preferably carried out by means of an analog gravure method and / or a digital printing process. The gravure procedure is a printing technique in which the elements to be reproduced are presented as concavities in a printer form that is inked before printing. Printing ink is mostly found in the concavities 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 gravure or indirect gravure. Gas filled microspheres may be contained in one or more inks. However, it is also conceivable that gas filled microspheres can be applied separately.

In digital printing, the print image is transmitted directly from a computer to a printing machine, such as a laser printer or an inkjet 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 done with 1 to n single-color printheads or with 1 to n multi-colored printheads (eg CYMK).

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

It is also conceivable to combine the indicated gravure printing and digital printing techniques. A suitable combination of printing techniques can be performed on the one hand directly on the material board or on the layer to be printed or also before printing by adapting the used electronic data sets. For example, a first decorative layer in gravure and other decorative layers in gravure and / or digital printing can be applied, or a first decorative layer in digital printing and other decorative layers in gravure and / or digital printing can be applied.

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% in 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 of plastic pellets filled with propellant gas. Suitable propellant gases can be hydrocarbons in the form of gas, 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 at least one and the other decorative layer be 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 at least one decorative layer, in particular in the case of a 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 explained above, the printing ink used for the decorative layer can be applied in rotogravure 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 printing ink. Printing ink is transmitted by the printing cylinder to the material board. By means of a suitable control, such as the control of the repetition of the drawing, it is guaranteed 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 the software with the black (key). Here, an additional printing ink is also printed from a certain amount of black. Another possibility is to add the microspheres directly to the ink of printing for the pore or black. Of course, the process can also begin with a digital print, in which a first printing ink is printed as the first decorative layer. Next, the second printing ink containing the gas-filled microspheres in the pore area is printed with a printing cylinder. In another variant of the present process it can also be provided that the at least one decorative layer or the other decorative layers comprise other additives to generate a nacre or metal shine, flash effects, night luminescence or thermochromic effects.

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

In one embodiment, the at least one protective layer contains an aqueous resin, at least one varnish that can be dried by radiation 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 to direct printing, eg selected from the group of acrylates, modified acrylates and / or epoxides; or also polyurethanes that have good adhesion properties. Especially preferably, aqueous resins are used. After the beginning of drying (as the beginning of hardening or beginning of gelation) of the protective layer, intermediate storage of the printed boards is possible without the danger of damage to the surface or soiling of the decorative layer. Therefore, no problems are expected, such as getting the boards dirty or suffering abrasion and / or a detachment of the decoration, even in the case of undefined time intervals between a machining stage of the decoration printing and Another machining stage. Therefore, it is also guaranteed that printers should not interrupt their work in the event of a service interruption in subsequent processing.

In one embodiment, the protective layer to be applied in the decorative layer of the material board comprises at least one water-compatible resin, preferably a resin containing formaldehyde, especially preferably melamine-formaldehyde resin, resin of urea-formaldehyde and / or melamine-urea-formaldehyde resin. Therefore, 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 may also have abrasion resistant particles, such as corundum, glass spheres, cellulose fibers and other additives.

Next, the protective layer comprising the at least one water-compatible resin is dried or pre-dried until the resin is still fluid and can crosslink. 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 derived from wood. Depending on the amount applied, the pre-drying process can last from 5 to 15 seconds, preferably from 5 to 10 seconds.

If a varnish that can be dried by radiation is used as a protective layer, the beginning of gelation of the protective layer that follows the application of the protective layer can be carried out using ultraviolet radiation (eg with 320-400 nm) , electronic beam radiation and / or NIR radiation. After the beginning of gelation, the varnish preferably has a degree of polymerization between 20 and 60%, preferably between 30 and 50%.

In another variant of the present process, the protective layer to be applied on 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 accordance with the invention 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 particles that reduce wear. The multi-layer wear protection layer can be applied with the following stages:

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

- drying of the other resin layer.

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 wear resistance preferably comprise corundum (aluminum oxides), boron carbides, silicon dioxides, silicon carbides, the use of corundum being especially preferable. In one embodiment, the amount of abrasion resistant particles scattered 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

The amount of the second resin layer applied to the protective layer may be between 10 and 50 g / m2, preferably between 20 and 30 g / m2, especially may 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 resin layer can also be dispensed with.

In another embodiment of the present process, at least a third layer of resin is applied respectively on the upper face and the lower face of the board of wood-derived matter, that is, on 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 may contain glass spheres, the glass spheres preferably acting as spacers. The glass spheres used preferably have a diameter of 50 to 100 pm, preferably 60 to 80 pm. The applied amount of the glass spheres when they are applied together with the third layer of resin 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 resin applied. 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 50. 80% by weight, preferably between 60 and 70% by weight, especially preferably between 60 and 65% by weight, being, for example, 61.6% by weight.

In another variant of the present process, the resin to be applied as the fourth resin layer may contain glass spheres and / or fibers, in particular cellulose fibers. If 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 amount of fibers applied, such as cellulose fibers, when they are applied together with the fourth resin layer, is between 0.1 and 0.5 g / m2, preferably between 0.2 and 0, 4 g / m2, especially preferably is 0.25 g / m2. The addition of glass spheres and / or fibers such as cellulose fibers to the fourth layer provided above contributes to the wear resistance of the material board.

It is also possible and provided that the bottom face of the material board is also provided with one or several layers of resin. In this case, the resin layers on the underside of the material board do not contain particles that reduce abrasion, 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 board in at least one double application device (cylinder application group).

The resin layer (s) applied on the underside of the material board acts as a contraction. Thanks to the application of the resin layers on the upper face and the lower face of the material boards in approximately the same quantities, 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 Contraction applied to the lower face corresponds to the layer structure and the corresponding thickness of the layers approximately to the sequence of layers applied to the upper face, with the difference of abrasion resistant particles and glass spheres.

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

The amount of the second resin layer applied on the underside of the wood-derived matter board may be between 30 and 80 g / m2, preferably between 40 and 60 g / m2, especially preferably 50 g / m2

The amount of the third layer of resin applied on the underside of the board of wood-derived matter may be between 20 and 70 g / m2, preferably between 30 and 50 g / m2, especially preferably 40 g / m2 with a solids content between 50 and 70% by weight, preferably between 50 and 60% by weight, the same being particularly preferably 55% by weight.

The amount of the fourth layer of resin applied on the underside of the board of wood-derived matter may be between 10 and 60 g / m2, preferably between 20 and 50 g / m2, especially preferably 30 g / m2 with a solids content between 50 and 70% by weight, preferably between 50 and 60% by weight, the same being particularly preferably 55% by weight.

It should be added that to all resin layers other additives can be added, such as hardeners, crosslinkers, defoamers and / or non-sticks.

The final resin layer applied respectively on the upper face and on 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 until a residual humidity is reached between 6 and 9% by weight, eg in a circulating air dryer.

In the pressing stage that follows the last stage of drying, a 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 process therefore allows the manufacture of a printed material board with the following layer structure: material board, at least one decorative layer applied in direct printing on the upper face of the material board, the at least one layer comprising decorative at least one additive in the form of gas-filled microspheres; and at least one layer of protection that has at least begun to dry.

In a first preferable embodiment, the printed material board has the following layer structure: material board - resin layer (laminate base layer) - primer layer (s) - first decorative layer - second decorative layer with microspheres full of gas - protective layer - wear protection layer (s). Each of these layers can be presented in one or several layers. In general, it is possible to present, for example, several layers of primer and one layer of primer.

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 is provided on the upper face and the lower face of the board of material derived from the wood, and may be contained in the third and fourth layer of resin provided on the upper face of the board of matter derived from wood respectively glass spheres and / or fibers, in particular cellulose fibers.

In a preferable embodiment, the present process allows the manufacture of a printed material board with the following layer structure (viewed from the bottom up):

Four layer resin shrinkage - material board - primer layer - first printed decorative layer - second printed decorative layer with gas-filled microsphere protection layer - first resin layer - abrasion resistant particle layer - second layer of resin - third layer of resin with glass spheres - fourth layer of resin with glass spheres and / or cellulose fibers.

The present process for the manufacture of a printed material board is performed on a manufacturing line comprising at least one printing device for the application of a printed decorative layer containing the gas filled microspheres, at least one application device for applying the protection layer and at least one drying device for starting to dry the protection layer, the at least one application device for the protection layer being arranged behind the printing device seen in the machining direction.

To carry out the present process, it is also advantageous that at least one sanding device is provided in the manufacturing line for sanding the surface of the material board. The at least one sanding device is arranged in front of the printing device seen 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 (e.g. in shape of a convection dryer), the two devices being arranged behind the sander seen in the machining direction.

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

In another variant embodiment of the present manufacturing line, at least one application device for the primer layer with subsequent convection dryer followed by at least one application device, preferably two, is arranged next to the primer application device. 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 different layers to be applied can be made in the form of a cylinder, spraying device or casting device, and the drying devices arranged respectively behind the application devices can be presented in the form of a convection dryer, a dryer infrared and / or a NIR dryer (near infrared).

The application device for the decorative layers may comprise at least one printing cylinder and / or at least one digital printer, and in the case of a digital printer a digital printer with 1 an print heads of a single color or with 1 an can be used multicolored printheads.

In a preferable embodiment, the structure of a (first) manufacturing line until the application of the protective layer in a first production section has the following aspect:

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 particular infrared group 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 resin layer (laminate base layer) on the material board (sanding);

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

d) a second application device disposed behind the first application device seen in the machining direction to apply at least one primer layer on the material board, the second application device comprising at least one, preferably two, especially four application mechanisms are preferable;

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

f) a third application device disposed behind the second drying device for drying the at least one primer layer seen 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 seen 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 seen in the machining direction to apply at least one decorative layer, the fourth application device may comprise several printing cylinders for gravure printing (e.g. eg triple or quadruple printing cylinders) and / or a digital printer;

i) a fifth application device arranged behind the fourth application device to apply the decorative layer seen 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 protection layer seen in the machining direction to begin drying the at least one protection layer.

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

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

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

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

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

- at least a 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 preferable embodiment, the second manufacturing line for performing the present process in the second production section further comprises:

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

- 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 may 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 or fiber spheres);

- at least a fourth drying device arranged behind the fourth application device seen in the machining direction to dry the fourth layer of upper and lower resin; 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 on a manufacturing line where they can be applied by various application mechanisms with aqueous resin cylinders on printed and printed boards. At the beginning of the process a strip of resin is applied to some boards, on which the abrasion resistant material is subsequently spread as corundum with the spreading device.

The spreading device provided in the present (second) manufacturing line is suitable for spreading dust, 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. Cylinder rotation speed depends on the amount of abrasion resistant material applied.

In an embodiment of the present second manufacturing line it is further provided that the at least one spreading device is wrapped by at least one cabin, which is provided with at least one means for removing dusts that occur in the cabin or that be arranged inside of it. The means for removing dusts can be made in the form of a suction device or also as a device for blowing air. He Air insufflation can be achieved by means of nozzles that are installed in the inlet and outlet of the panels and blow air into the cabin. In addition, they can prevent an unevenly scattered curtain of abrasion resistant material from being formed by air movements.

The removal of dust from abrasion-resistant material from the environment of the spreading device is advantageous, since in addition to the obvious damage to the health of operators working in the production line, fine dust from abrasion-resistant particles is also deposited in other parts of the installation of the production line and leads to greater wear of it. The arrangement of the spreading device in a cabin therefore serves not only to reduce the damage to health by dust in the environment of the production line, but also prevents 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 seen in the machining direction. The control of the spreading device by means of a light barrier is advisable, since between the different boards of material derived from the wood there are more or less large gaps. 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 for collecting excess abrasion resistant particles (i.e. abrasion resistant particles that do not spread on the at least one board of material derived from the wood, but instead fall before the entrance of the board of matter derived from the wood with the help of the transport device below the spreading cylinder thereof).

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. Screening meshes of the screening device correspond to the largest grain used in the abrasion resistant particle material (ie, approx. 80 to 100 pm). In the screening 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 screened abrasion resistant material can be returned (recycled) in the screening device. spreading.

Next, the invention will be explained in more detail with reference to the Figures of the drawings with an exemplary embodiment. They show:

Figure 1 a schematic representation of a first manufacturing line of a printed material board applying the method according to the invention.

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

First manufacturing line of Figure 1

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

Next, a first resin application (base layer of laminate) 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 coating is used as the coating resin. solids part of 60% by weight.

Next, the white primer containing casein-based water and inorganic pigments is applied with the help of four application mechanisms 5 and dried after each application by hot air in a convection dryer 6. The different application mechanisms 5 apply amounts Different from primer. The total white application varies according to the printing requirements between 20 g / m2 and 30 g / m2.

Next, the application of a primer layer 7 with subsequent drying in another convection dryer 8 takes place. Then printing 9 (decoration) of the boards in indirect gravure takes place. Here, a decorative layer with dye pigments is printed first and then another decorative layer that has gas-filled microspheres is printed.

After printing, the boards are coated with melamine-formaldehyde resin 10 (protective layer) and also begin to dry in a convection dryer 11. Next, the boards are stored for a few days on an intermediate basis, before continue machining in a second manufacturing line (Figure 2). The priming process is especially important, since it substantially influences the quality of color printing of coated HDF boards. For a given color drawing it also has to be guaranteed a quantity of application of white as constant as possible, since if different luminous intensities of the primer cannot be presented and, therefore, also different colors in a color drawing 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 printed HDF boards, as well as four convection dryers 12a, 13a, 14a, 15a arranged behind the double application groups seen in the machining direction.

Behind the first application cylinder 12, a first spreading device 10 is also provided for uniformly spreading the wear-resistant material, such as corundum, on 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 double application mechanism 13 is arranged to apply a second resin layer and a second convection dryer 13a to dry the second resin layer.

Following the third double application mechanism 14 to apply the third resin layer, another spreading device 20 may be arranged to apply glass spheres on the third resin layer, followed by a third convection dryer 14a to dry the third layer of 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 may contain eg cellulose fibers on the upper face in a fourth double 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.

Embodiment Example 1

a) Cleaning sanding: Some HDF boards measuring 2600 to 5600 mm long, 2070 wide and 5 to 15 mm thick are sanded / cleaned in 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) Primer with melamine resin: With a cylinder 20 to 30 g of melamine resin fl./m2 are applied. The solids content of the resin is approximately 55% by weight. Then, the primer is 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 cylinder application mechanisms, 5 to 6 g of the pigmented primer per m2 are applied respectively and dried after each application. The water-based primer contains as a pigment titanium dioxide and as a casein binder or soy protein.

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

e) Decoration application: a wooden decoration is applied in gravure on the printed HDF board and provided with the primer layer. It is a three-color print, in which the pore structure is applied in the last printing mechanism. In another printing mechanism, a printing cylinder with the identical structure to that of the pore cylinder is made available. 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 that the printing ink is in the same areas as the pore ink by controlling the repetition of the drawing.

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

The subsequent machining takes place in the second manufacturing line according to Figure 2.

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

In the other stages of production, 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 sheet for pressing. After each application an intermediate drying is intercalated. Melamine resin is also applied on the lower face in the cylinder application groups. The amount applied on the upper face at the end of the resin application must reach similar amounts as on the lower face. h) After the last stage of drying, 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 brightness with respect to the surface had been generated in the area of the structure thanks to the expansion of the microspheres.

Embodiment example 2:

On a printed HDF board and provided with a primer layer according to the development of the procedure described above, a wooden decoration with digital printing was applied. It was a four-color print (CMYK). Printing inks had water as a solvent. In an additional set of printheads a transparent printing ink was applied. 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. Approximately 0.7 g / m2 of this printing ink was printed, guaranteeing by coupling with the black that this printing ink would be in the same areas as the pore ink. Next, the printed board was further machined as in the procedure described above. After pressing the board, it was shown that a difference in the degree of brightness with respect to the surface had been generated in the structuring area thanks to the expansion of the microspheres.

Claims (15)

1. Procedure for the manufacture of a material board provided with a decorative layer, comprising the following stages: - making available at least one material board 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 top face of the material board; - application of at least one decorative layer in direct printing on the upper face of the at least one material board, the at least one decorative layer comprising at least one additive in the form of gas-filled microspheres; - application of at least one protective layer on the at least one decorative layer; - 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, the wear protection layer being applied with the following steps: - application of at least a first resin layer 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 resin layer on the first dried resin layer, provided with 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 between 100 and 1000 N / cm2, expanding the gas-filled microspheres. 2. Method according to claim 1, characterized in that a chipboard, a medium density fiberboard (MDF), high density fiberboard (HDF) or oriented fiberboard (OSB) is used as the material board. or a plywood board. 3. Method according to one of the preceding claims, characterized in that at least the upper face of the at least one material board is subjected to at least one sanding process before printing. 4. Method according to one of the preceding claims, characterized in that at least one primer layer is applied on the upper face of the material board. 5. Method according to one of the preceding claims, characterized in that the at least one decorative layer is applied in a gravure procedure or in a digital printing process. 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 between 0.1 and 50% by weight, preferably between 0 , 5 and 30% by weight, especially preferably between 1.0 and 10% by weight. Method according to one of the preceding claims, characterized in that the gas filled microspheres are formed by plastic pellets filled with propellant gas. Method according to one of the preceding claims, characterized in that the at least one decorative layer is applied in an amount of between 0.1 and 10 g / m2, preferably between 0.5 and 5 g / m2, of especially preferable between 0.7 and 1 g / m2. Method according to one of the preceding claims, characterized in that more than one decorative layer is applied in direct printing. Method according to one of the preceding claims, characterized in that the at least one protective layer contains an aqueous resin. Method according to one of the preceding claims, characterized in that the amount of the first resin layer applied in 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, especially preferably in 55% by weight. 12. Method according to one of the preceding claims, characterized in that a second, third and fourth resin layers are applied on the first resin layer in the multi-layer wear protection layer. 13. Method according to claim 12, 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, 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, particularly preferably 55% in weight. 14. Method according to claims 12 or 13, characterized in that the resin to be applied as a third layer of resin contains glass spheres in an amount of 1 to 5 g / m2. 15. Method according to claims 12 or 13, characterized in that the resin to be applied as a fourth layer of resin contains glass spheres in an amount of 1 to 5 g / m2.