EP1859912B1 - Process and apparatus for manufacturing a panel - Google Patents

Abstract

The method involves heating the embossing roll (4) from two hundred to five hundred degree celsius. The panel (1) is introduced between the embossing roll and a counter roll (5). A structure is embossed with a depth up to five hundred micrometers into the heat-activated synthetic resin layer on the top side (2) of the panel with a pressure of five hundred ninety to nine thousand four hundred seventy newton per centimeter square. An independent claim is also included for the application of embossing roll in the method.

Description

The invention relates to a method for producing a panel, in particular a wall, ceiling or floor panel of split wood-based panels with side edges, which have a decor on the top and / or bottom, which is coated with a heat-activatable resin or a radiation-curable lacquer and the structure of wood-based panel, decor and synthetic resin or lacquer layer is pressed together by means of at least one embossing roller and at least one counter-pressure roller. In addition, the invention relates to an apparatus for carrying out such a method.

The production of panels, especially wall, ceiling or floor panels is known. For production, a coating is applied to a wood-based panel, for example an MDF or HDF board. The coatings used for this purpose are available in a variety of decors and show, for example, wood decors, stone decors but also fantasy decors. In order for these decors to be able to imitate a natural material as precisely as possible, the coating materials are embossed with a three-dimensional structure that corresponds as closely as possible to the natural material. This means that when comparing the natural material with the imitation on the coating, if possible no difference ____________ should exist between the two surfaces. This presupposes that the three-dimensional structure of the surface, for example of a real wood panel, is reproduced as exactly as possible from the artificial surface of the coating material. This means that the individual wood pores and the three-dimensional relief resulting from the early wood and late wood differences is reproduced by an embossing of the coating material. This is known, for example, as embossing a synchronous pore.

From the DE 103 56 387 B4 a device and a method for smoothing surfaces of workpieces made of wood or wood-based materials is known. To smooth the surface, a heated smoothing tool with a temperature of 200 to 450 ° C over the surface of the workpiece made of wood or wood-based material.

The production of decorsynchronous structures takes place in special presses, which provide a corresponding press plate for each decor or for each structure. The press plates are called synchronizer plates. By means of the synchronous plates, the grain is then pressed at the corresponding point of the coating material, for example an impregnated paper. For deep and authentic pores, stable presses are needed which allow a pressure of at least 390 N / cm ² (40 kg / cm ² ). The smaller the surface to be pressed, the lower the pressure needed for embossing. For example, a joint in tile structures can be produced at a lower pressure than a so-called handscraped pattern (superimposed structure, eg a wood structure with a worn surface in which the height differences of early and latewood are pressed into the surface of the panel) over a larger area because the pressure can be made more selectively. For deep handscraped patterns very large pressures, at least 785 N / cm ² (80 kg / cm ² ) are needed. The presses that make it possible to work with such high pressures are very costly and are therefore not frequently used in industry. In addition, the utilization of these presses is currently low. If the pore type is to change, a new and costly press plate must be purchased for each of these presses. The problem with this is that this is a time-consuming and expensive process.

From the WO 97/31776 A1 For example, a process is known in which a structure is coined by means of rolling into the surface of a laminate before the top layer of the laminate cures completely. The disadvantage is that the embossing of the structure must be done immediately after the production of the laminate, since a subsequent imprinting of a structure in a fully cured topmost layer of a laminate is not possible.

The EP 0 345 790 A2 also discloses a method of embossing a structure by rolling into the surface of a panel. Also in the method proposed in this document, the structure is embossed before drying the applied layers. This must therefore be done immediately. In the US 2003/0207083 A1 a method is proposed in which a structure is introduced into the surface of a panel before the final curing of the panel. Also in this case, therefore, the impression of the structure must be made immediately after the manufacture of the panel. A temporary storage is not possible in this case.

In the EP 1 454 763 A2 For example, a structure is impressed into its surface during the pressing of a wood-based panel with the layers applied to it. The disadvantage is that to change the einzuprägenden structure, a new press plate must be made, which then has to be used in the press used. This is costly and time consuming.

The DE 10 2004 033 237 A1 discloses a method in which decorative laminates are provided with a surface structure. In this case, an ink used for the production of the decorative layer of the laminate is mixed with an additive which prevents the wetting of the printed layer with later to be applied impregnating resins. These resins thus accumulate only in areas of the laminate surface which were not printed with the ink added with the additive. adversely is that also in this case, the structure must be made during the manufacturing process of the panel. If the structure to be produced does not follow the printed image of only one color, which is generally the case, for example, with woodgrain decors, an additional, optionally colorless, layer which is mixed with the additive is to be applied here. This makes the process complicated and time-consuming.

The DE 27 06 538 discloses a method of embossing or burning a pattern into a plate, for example made of wood or of a hardened gypsum core, on the at least one side of which a paper or felt layer is applied. The embossing tool must be heated to a very high temperature due to the extremely high surface hardness of the materials to be embossed, which is why it quickly becomes unusable due to oxidation and wear. This problem is encountered in the cited document by choosing an optimal temperature interval.

The US 2004/0086678 discloses a method for producing a structured surface of a panel wherein a base coat is first applied to the core to provide a textured surface. Subsequently, a pattern or decor is printed on this surface, which is finally covered with a protective layer.

Based on this problem, it is an object of the invention to simplify the production of panels with decorated surface and to allow embossing in panels without special press plates.

• Aufheizen der Prägewalze auf eine Temperatur von 200 - 500°C,
• Einführen des Paneels zwischen Prägewalze und einer Gegendruckwalze,
• Prägen einer Struktur mit einer Tiefe bis zu 500 µm in die hitzeaktivierbare Kunstharz- oder Lackschicht auf der Ober- und/oder Unterseite des Paneels mit einem Druck von 196 - 1470 N/cm² (20 - 150 kg/cm²).

To solve the problem, the method for producing a generic panel characterized by the following steps:

• Heating the embossing roll to a temperature of 200-500 ° C,
• Inserting the panel between the embossing roller and a counterpressure roller,
• Embossing a structure having a depth of up to 500 μm into the heat-activatable synthetic resin or lacquer layer on the top and / or bottom of the panel at a pressure of 196-1470 N / cm ² (20-150 kg / cm ² ).

Due to the subsequent deep embossing with an embossing roll, an embossing depth of 80 to 500 μm, preferably 250 μm, of split panels can be achieved before the profiling. For this purpose, both the embossing roller and the counterpressure roller are heated to a temperature of 200-500.degree. C., preferably 230-350.degree. C., in particular preferably 250.degree. Due to the high temperature, the synthetic resin or the lacquer layer is melted on the top and / or bottom of the panels, so that over the embossing roll a structure, e.g. a three-dimensional image of a wooden surface into which the panel surface can be embossed. For embossing, the panel is inserted between the embossing roller and a counter pressure roller, which provides the propulsion.

The faster the production speed achieved, the higher the temperature of the embossing roll must be. Advantageously, by using the rollers, it is possible to apply a high pressing pressure of 590-1470 N / cm ² (60-150 kg / cm ² ), preferably 785-1175 N / cm ² (80-120 kg / cm ² ) to achieve a depth impression to a depth of up to 500 μm. Is an embossing depth of up to 500 microns desired, so can be embossed with the embossing roll both in the molten melamine layer as well as in the underlying wood material. Advantageously, superimposed structures with the embossing rollers, so-called. Handscraped patterns, such as surfaces of worn wood floors can be reproduced with significant early wood latewood differences.

But it is also possible to impress with the embossing rollers decor-synchronous structures without handscraped pattern in panels in order to achieve the most accurate imitation of a natural material.

By arranging several embossing rollers in succession, different structures can be embossed into a panel.

It has been shown that chamfers can also be imprinted into the side edges of the panel by the embossing roller and possibly also additionally. Advantageously, such machining costs can be saved, since a machining of the panel side edges to produce the chamfers is no longer necessary. Since the panel is already coated with a decor and a synthetic resin prior to the embossing of the chamfers, a surface seal of the chamfer, e.g. by painting, which takes place after a machining, after the embossing no longer necessary. Subsequent painting is critical, especially in the case of structured surfaces, as the three-dimensional structure can be covered again by applying the varnish.

Since the panels can be deformed banana-like by the high pressure and high temperatures during the embossing, it is advantageous to cool the panels after the embossing by rolling. As a result, the deformation can be corrected again.

With the method according to the invention it is also possible to emboss already embossed panels with the embossing roll so as to produce superimposed structures on the surface of panels.

The synthetic resin layer on the top and / or bottom of the panels may be directly applied by one or more printing operations. In order to realize particularly thick synthetic resin layers, the synthetic resin can be applied with a basis weight of about 200 to 300 g / m ² . As synthetic resins, it is possible to apply not only melamine resin but also other amino resins, for example urea or phenolic resins or other synthetic resins. Also, the lacquer layer can be applied by one or more printing operations directly on the top and / or bottom. Preferably, an electron beam curable varnish with wear and scratch-inhibiting additives is used. Of these, about 150 g / m ² can be applied. The lacquer layer is then further fully cured with an electron beam with a dose rate of 60 kGray. After structuring, the gloss level is greater than or equal to 85 units (measurement according to EN ISO 2813 at an angle of 60 °).

The throughput speed can be 10 to 60 m / min. It is preferably 30 m / min. The embossing line pressure can be 590 to 1470 N / cm ² (60 to 150 kg / cm ² ).

• Aufheizen der Prägewalze auf eine Temperatur von 200 - 500°C,
• Einführen des Paneels zwischen Prägewalze und einer Gegendruckwalze,
• Prägen mindestens einer Fase an mindestens eine Seitenkante (I, II, III, IV) des Paneels (1) mit einem Druck von 196 - 1470 N/cm² (20 - 150 kg/cm²) durch die Prägewalze.

To solve the problem, another method for producing a generic panel is characterized by the following steps:

• Heating the embossing roll to a temperature of 200-500 ° C,
• Inserting the panel between the embossing roller and a counterpressure roller,
• Embossing at least one chamfer on at least one side edge (I, II, III, IV) of the panel (1) with a pressure of 196-1470 N / cm ² (20-150 kg / cm ² ) through the embossing roller.

By means of this method, a chamfer can also be embossed on the side edges of panels which have no deep embossing. The embossing is carried out under high pressure and leads to a deformation of the decorative and synthetic resin or lacquer layer and the underlying wood-based panel. Subsequent sealing of the chamfer surface is not necessary because the decorative and synthetic resin or lacquer layer is not removed. The costs for a subsequent sealing of the chamfer surface are eliminated and the production costs can be reduced. The embossing rollers have a corresponding profile for chamfering on the sides.

The radiation-curable lacquer used can be the previously described electron-beam-curable lacquer.

A device according to the invention for producing a panel, in particular a wall, ceiling or floor panel, from split wood-based panels with side edges, which have a decor on the top and / or bottom, which is coated with a heat-activated resin or a radiation-curable lacquer, and in which the structure of the panel made of wood-based panel, decor and resin or lacquer layer is pressed together with at least one embossing roller and at least one counter-pressure roller is characterized in that the embossing roller can be heated to a temperature of 200 to 500 ° C and that a structure with a depth of up to 500 microns in the heat-activatable resin or lacquer layer on the top and / or bottom of an inserted between the embossing roller and the platen roller panel with a pressure of 196 to 1470 N / cm ² (20 to 150 kg / cm ² ) can be imprinted.

Advantageously, the rollers, embossing and counter-pressure roller panel width and correspond in the extent of a panel length. This ensures that the embossed pattern does not repeat on a panel. Advantageously, such narrow rollers can be produced within a very short time and can be changed easily. Thus, production and investment costs can be kept low.

Advantageously, the embossing of already embossed panels, for example, a Have synchronous pore, obtained in a subsequent embossing means of the heated embossing roll, so that two superimposed embossed images can be generated, which can complement each other.

Also, the platen roller may have a pattern or a surface roughness to prevent slippage of the panel due to the high pressure. For example, this pattern may be a herringbone pattern, but a three-dimensional logo, such as a company logo, may be used to increase roughness. Using a roller with a logo as a pressure roller, it is also possible, among other things, stamping logos or logos on the top of the panel in a cost-effective and timely manner, in order to achieve a high recognition value, e.g. in a marketing action, for the manufacturer to achieve.

With the method according to the invention, a multiplicity of different structures can be embossed into the surface of panels. For example, surfaces can be created with a handscraped design or tile joints and tile surfaces, embossed V-joints or rolls of different sizes with different radii irregular V-joints as well as deep syn-chronporen and the imitation of signs of age or wear of wood surfaces and last company logos or lettering on the bottom or top of the panels.

A generic panel is characterized in that the structure at least partially has a depth of 500 microns and at least the surface of the top is high gloss. High gloss means here that the gloss level is greater than or equal to 85 units (measurement according to EN ISO 2813) at an angle of 60 °.

With this embossing depth particularly deep structures, for example, handscraped patterns can be generated, which also under haptic aspects a particularly allow good imitation of the imitated material. Advantageously, the decor can have a wood, tile or fantasy pattern. These patterns can be enhanced by the imprinting of particularly deep structures in their authentic effect. The decor or the decorative layer may consist of at least one layer, which is executed or applied either as a resin-impregnated paper or in a direct printing process. Advantageously, to increase the similarity between the natural decor and the decor on the panel surface, the structure is executed decorsynchronously.

The use of an electron-beam-hardening lacquer results in a particularly high-gloss surface.

The structure can be embossed both in the top and in the bottom of the panel.

Figur 1 -

den Verfahrensablauf zur Erzeugung einer Prägung mit Holzstruktur auf der Oberfläche eines Paneels und

Figur 2 -

den Verfahrensablauf zur Erzeugung eines Fantasiedekors mit Fugenstruktur auf der Oberseite eines Paneels.

Reference to a drawing, an embodiment of the invention will be explained in more detail. Show it:

FIG. 1 -

the procedure for the production of an imprint with wood structure on the surface of a panel and

FIG. 2 -

the procedure for creating a fantasy decor with joint structure on top of a panel.

FIG. 1 shows the method for producing a panel 1, in particular a floor panel with side edges I, II, III, IV, which has a decor on the top 2 and is coated with a heat-activatable resin. Decor and synthetic resin layer have been pressed together. The panel 1 is inserted between the embossing roller 4, which has a temperature of about 350 ° C, and the platen roller 5. By the embossing roll 4, a pressure of 1175 N / cm ² (120 kg / cm ² ) is applied to the top 2 of the panel 1. Due to the heated embossing roll 4, the heat-activatable synthetic resin is activated on the upper side 2 of the panel 1 and the high pressure causes a so-called hand-scraped design to be impressed in the upper side of the panels 1. The feed of the panel 1 is realized by the counter-pressure roller 5, which presses against the underside 3 of the panel 1 and has a herringbone pattern to increase the surface roughness. Due to the high embossing temperature, the heat-activatable synthetic resin layer of melamine is melted on the surface and can thus be subsequently deformed. The embossing of the structure takes place here both in the melamine resin layer and in the underlying wood material.

FIG. 2 shows the inventive method after FIG. 1 with the difference that instead of a wood structure in handscraped design a fantasy pattern with tile joints in the top 2 of the panel 1 by means of an embossing roller 4 is impressed.

The process does not change if, instead of a heat-activatable synthetic resin, a heat-activatable, radiation-curable, in particular electron-beam-curing lacquer is used.

At the side edges I, II, III, IV, the panel 1 is provided with mutually corresponding spring / groove profiles with integrated locking means for releasably connecting adjacent panels.

LIST OF REFERENCE NUMBERS

1

paneling

2

top

3

bottom

4

embossing roller

5

Backing roll

I

side edge

II

side edge

III

side edge

IV

side edge

Claims (22)

1. Method for producing a panel (1), in particular a wall, ceiling or floor panel, made of divided wood-based material boards with side edges (I, II, III, IV), which have a decoration on the upper and/or lower side (2, 3), which decoration is coated with a heat-activatable synthetic resin or a radiation-curable varnish, and the structure of wood-based material board, decoration and synthetic resin or varnish layer is pressed together by means of at least one embossing roller (4) and at least one counter-pressure roller (5) comprising the following steps:

   - heating the embossing roller (4) to a temperature of 200 to 500°C,

   - introducing the panel (1) between the embossing roller (4) and a counter-pressure roller (5),

   - embossing a structure with a depth of up to 500 µm into the heat-activatable synthetic resin or varnish layer on the upper and/or lower side (2) of the panel (1) at a pressure of 196 to 1,470 N/cm² (20 to 150 kg/cm²).
2. Method according to claim 1, characterised in that decoration-synchronous structures are embossed in panels (1).
3. Method according to claim 1 or 2, characterised in that a plurality of embossing rollers (4) are arranged one behind the other and different structures are embossed in the panels (1).
4. Method according to any one or more of the preceding claims, characterised in that chamfers are embossed on at least one side edge (I, II, III, IV) of the panels (1) with the embossing roller (4).
5. Method according to any one or more of the preceding claims, characterised in that the panels (1) are cooled after the embossing by rollers.
6. Method according to any one or more of the preceding claims, characterised in that previously embossed panels (1) are embossed by the embossing roller (4).
7. Method according to any one or more of the preceding claims, characterised in that the synthetic resin layer is applied by one or more printing operations.
8. Method according to claim 7, characterised in that the synthetic resin layer is applied with a weight per unit area of 200 to 300 g/m².
9. Method according to claim 7 or 8, characterised in that a melamine resin layer is applied.
10. Method for producing a panel (1), in particular a wall, ceiling or floor panel, made of divided wood-based material boards with side edges (I, II, III, IV), which have a decoration on the upper and/or lower side (2, 3), which decoration is coated with a heat-activatable synthetic resin or a radiation-curable varnish and the structure of wood-based material board, decoration and synthetic resin or varnish layer is pressed together by means of at least one embossing roller (4) and at least one counter-pressure roller (5) comprising the following steps:

    - heating the embossing roller (4) to a temperature of 200 to 500°C,

    - introducing the panel (1) between the embossing roller (4) and a counter-pressure roller (5),

    - embossing at least one chamfer on at least one side edge (I, II, III, IV) of the panel (1) at a pressure of 196 to 1,470 N/cm² (20 to 150 kg/cm²) by means of the embossing roller.
11. Method according to claim 1 or 10, characterised in that the temperature is 250°C.
12. Method according to claim 1 or 10, characterised in that the structure has a depth of 250 µm.
13. Method according to claim 1, 10 or 12, characterised in that the structure has a depth of at least 80 µm.
14. Method according to claim 1 or 10, characterised in that the linear pressure is 590 to 1,470 N/cm² (60 to 150 kg/cm²).
15. Method according to any one or more of the preceding claims, characterised in that the throughput speed is 10 to 60 m/min.
16. Method according to claim 15, characterised in that the throughput speed is 30 m/min.
17. Method according to claim 1 or 10, characterised in that the varnish layer is electron beam-curable.
18. Method according to any one or more of the preceding claims, characterised in that the structure is embossed in the upper side (2) and the lower side (3).
19. Device for producing a panel (1), in particular a wall, ceiling or floor panel, made of divided wood-based material boards with side edges (I, II, III, IV), which have a decoration on the upper and/or lower side (2, 3), which decoration is coated with a heat-activatable synthetic resin or a radiation-curable varnish, and in which the structure of the panel made of the wood-based material board, decoration and synthetic resin or varnish layer is pressed together by means of at least one embossing roller (4) and at least one counter-pressure roller (5), characterised in that the embossing roller (4) can be heated to a temperature of 200 to 500°C and has a structure such that a structure with a depth of up to 500 µm can be embossed into the heat-activatable synthetic resin or varnish layer on the upper and/or lower side of a panel introduced between the embossing roller (4) and counter-pressure roller (5) at a pressure of 196 to 1,470 N/cm² (20 to 150 kg/cm²).
20. Device according to claim 19, characterised in that the width of the embossing roller (4) corresponds to the panel width.
21. Device according to claim 19 or 20, characterised in that the periphery of the embossing roller (4) corresponds to the panel length.
22. Device according to claim 19, 20 or 21, characterised in that the counter-pressure roller (5) has a pattern, in particular a herringbone pattern or a three-dimensional logo.

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