WO2009141743A1

WO2009141743A1 - Method for manufacturing coated panels and coated panel

Info

Publication number: WO2009141743A1
Application number: PCT/IB2009/051620
Authority: WO
Inventors: Martin Segaert; Bart Verhaeghe
Original assignee: Flooring Industries Limited, Sarl
Priority date: 2008-05-20
Filing date: 2009-04-20
Publication date: 2009-11-26
Also published as: BE1018150A3

Abstract

Method for manufacturing coated panels comprising a substrate (2) and a top layer (3), and wherein the top layer (3) comprises at least a decor (4) and, provided thereover, a synthetic material layer (5) with hard particles (6), wherein the method comprises at least the step (S1), wherein at least said decor (4) and said synthetic material layer (5) are provided on top of each other by means of a press treatment by a structured press element (9), and wherein said synthetic material layer at the surface of the panel (1) comprises a resin layer (20) enriched with said particles (9), characterized in that in said step (S1) of assembling, a film (11) is situated between the press element (9) and said synthetic material layer (5), wherein a portion of the structure (12) of said press element (9) is impressed into said synthetic material layer (5) by the intermediary of said film (11) and at least a portion of said film (11) is removable from the obtained assembled entity (14). The invention also relates to panels which can have been obtained by means of such method.

Description

Method for manufacturing coated panels and coated panel.

This invention relates to a method for manufacturing coated panels, as well as to coated panels.

More particularly, the invention relates to a method for manufacturing coated panels, which are of the type comprising a substrate and a decorative top layer provided thereon. This may relate, for example, to floor panels substantially consisting of a substrate, for example, a MDF or HDF (Medium or High Density Fiberboard) panel and a top layer provided thereon, such as a veneer layer, a wooden top layer or a laminate top layer.

In particular, the invention relates to a method for manufacturing coated panels with a printed decor with a transparent or translucent layer of synthetic material extending there above. It is known that such decor can be printed directly on the substrate, whether or not by the intermediary of primer layers. However, the decor also may be provided on a material sheet, such as a paper sheet, which is incorporated in said top layer. The transparent or translucent synthetic material layer forms a protective layer above the printed decor and may comprise, for example, wear-resistant particles, such as aluminum oxide. It is not excluded that this protective layer also comprises a material sheet, such as a paper sheet. Such laminate floor panel may be manufactured, for example, according to a DPL (Direct Pressure Laminate) or HPL (High Pressure Laminate) technique. In the case of a DPL technique, one or more material sheets provided with resin are brought, together with the substrate, into a press device, where, by means of a pressing element and under the influence of increased pressure and temperature, they are connected to each other as well as to the substrate. In the case of a HPL technique, the top layer is formed separately on the basis of two or more material sheets provided with resin, before the thus obtained top layer is provided on the substrate, for example, by gluing it on the substrate.

Further, it is known that such coated panels can be scratch-sensitive, and it is possible that scratches already occur in the decorative top layer during the manufacture of such panels, as the panels therein often are transported and stacked upon each other at high speeds and in dust-rich surroundings. Of course, scratches may occur also during the actual use of such panels, for example, as a floor panel in a floor covering.

It is known that in order to enhance the scratch resistance of such floor panels, hard particles in the decorative top layer may be applied. Such solution is discussed, for example, in WO 2007/144718, in which is suggested, amongst others, applying at the surface of the coated panel a resin layer enriched with hard particles. Such solutions can be sufficient for the actual use of the panels, however, can not prevent the occurrence of scratches during the preceding manufacturing, packaging or processing thereof. Such scratches are disturbing and are absolutely undesirable, for example, in glossy panels. Moreover, the integration of hard particles in the decorative layer, and certainly when at least a portion of these particles is situated at the surface, may lead to an extensive wear at the production installations, such as, for example, wear at the press elements, milling machines or parts thereof applied in the manufacture of laminate panels. Press elements applied in the manufacture of laminate panels are expensive, certainly when they are structured for forming impressions or protrusions at the surface of said decorative top layer, for example, as is known from WO 01/96689 or WO 2006/066776, and/or when they comprise portions with a high gloss degree and/or when they comprise portions with different gloss degree. Re-etching or otherwise repairing a worn press plate also is rather expensive. As known, the problem of wear of the press elements as such can be addressed by providing wear-resistant covering layers on these press elements, such as described in WO 2008/120058 (PCT/IB2008/000649). However, such covering layers are expensive and in their turn can lead to scratches in the surface of the decorative layer of the coated panels.

The present inventions aims at an alternative method for manufacturing coated panels, which, according to various preferred embodiments of the invention, can offer a solution for one or more of the disadvantages or problems mentioned above in respect to the state of the art.

To this aim, the invention, according to its first aspect, relates to a method for manufacturing coated panels, wherein these panels are of the type comprising a substrate and a top layer provided thereon, and wherein the top layer comprises at least a decor and, provided thereover, a synthetic material layer with hard particles, wherein the method comprises at least the step of assembling said top layer, wherein at least said decor and said synthetic material layer are provided on top of each other by means of a press treatment by a structured press element, and wherein said synthetic material layer at the surface of the panel preferably comprises a resin layer which is enriched with said particles, with the characteristic that in said step of assembling, a film is situated between the press element and said synthetic material layer, wherein a portion of the structure of said press element is impressed into said synthetic material layer by the intermediary of said film and at least a portion of said film is removable from the obtained assembled entity.

By "removable" is meant that the respective portion of the film is provided for being removed by simple hand tools and preferably even without tools. Preferably, the film is removable at room temperature, 18-23°C. Preferably, no additional auxiliaries, such as solvents, water or heat are required for releasing the removable film.

According to the invention, said film forms a barrier between said particles and the structured press element, as a result of which this press element is less exposed to the wear-inducing hard particles, whereby this press element may be less subjected to wear and therefore may show a longer usage cycle. According to the invention, the structure of the press element still is impressed into the synthetic material layer, virtually through the film concerned. For an excellent transfer of the structure of the press element to the synthetic material layer, best a film is used having a thickness which is smaller than 100 μm and still better is smaller than 60 μm. Good values for the thickness of the film are between 20 and 55 μm. Preferably, such film as such is free from structures, except for a possible, quasi- uniform microstructure, such as a roughness, which, for the major part of the film, is smaller than 20 μm Ra and still better is smaller than 10 μm Ra. Preferably, films of synthetic material, such as polyethylene films or polyester films, are applied. Possibly, the applied films can be provided with a coating at one or both flat sides promoting the release from the synthetic material layer or having another function, such as the function of promoting the heat transfer between the press element and the surface of the coated panel. For example, in case an improved release is intended, they may be provided with a silicone layer, or, in case of an improved heat transfer is intended, they may be provided with a coating of aluminum or another metal.

The hard particles situated in the synthetic material layer are harder than the synthetic material present in this layer and may relate, for example, to ceramic particles, such as aluminum oxide, silicon carbide or titanium oxide. It is also not excluded that, for example, glass spheres or other hard particles are applied.

Said hard particles may have an average major dimension situated between 0.1 and 200 μm. It is known that for obtaining scratchproofness, preferably particles are applied with an average main dimension which is smaller than 60 μm, whereas for obtaining wear resistance preferably particles are applied with an average main dimension which is larger than 60 μm. Also, particles of different material and/or shape and/or main dimension may be used.

In the case of hard particles with different main dimensions, the hard particles with the possibly smaller main dimension preferably are situated closer to the surface of the top layer than the hard particles with the larger main dimension. Smaller particles result in less wear at the press element and moreover are suitable for imparting scratchproofness to the surface of the top layer.

The present invention is particularly interesting when at least a portion of the hard particles is situated at the surface of the top layer. This means that this portion of the particles is situated higher than any material sheet in this top layer. Namely, when manufacturing such coated panels, by means of the present invention the biggest improvement in the service life of the press element is obtained. Moreover, such panels have a very good resistance against scratches due to the presence of the resin layer enriched with hard particles at their surface.

In the case of hard particles with different shapes, the hard particles with the possibly oblong shape are situated closer to the surface of the top layer than the hard particles with the granular shape. Hard particles with an oblong shape as such already result in less wear at the press element.

It is clear that in the case of substantially granular particles, said main dimension relates to the diameter and that in the case of substantially oblong particles, said main dimension relates to the length of the particles concerned. Preferably, the method of the invention is applied for manufacturing coated panels, said decor of which relates to a printed decor. In such panels, predominantly an artificial structure on top is desired. However, it is not excluded that the invention is applied for manufacturing coated panels having other decors, such as for manufacturing coated panels having a veneer layer or another wooden top layer, which is thicker than veneer.

As aforementioned, the film preferably does not have a coarse structure. However, it may be provided with a microstructure, which, in the step of assembling, is transferred through the top layer of the coated panel and thereby determines the gloss degree of the top layer. The inventors have found that by means of synthetic material films, glossy or matte surfaces can be obtained at choice. Such surfaces are difficult to obtain when the press element, such as according to the state of the art, is brought into direct contact with the top layer to be formed. Therefore, the invention allows obtaining, with one and the same structured press element, depending on the choice of the intermediate film, a matte as well as a glossy structure, or possibly allows forming structures with a gloss degree lying in between. Where in the foregoing a matte structure is mentioned, this preferably relates to a structure with a gloss degree of less than 10 units, and where a glossy structure is mentioned, this preferably relates to a structure with a gloss degree of at least 30 units, each time measured in accordance with DIN 67530.

In a particular, preferred embodiment of the invention, the method, prior to said step of assembling, comprises at least the step of producing said synthetic material layer, wherein at least a portion of said synthetic material layer and said particles are provided on said film, wherein said film then is at least partially removable from the obtained assembled entity in that it comes off from at least a portion of said synthetic material layer. According to this embodiment, said film may serve as a carrier for a synthetic material layer with hard particles, which can be removed after the step of assembling, whether or not directly thereafter. It is known as such that a carrier sheet can be applied for providing a synthetic material layer with hard particles, however, according to the state of the art, such carrier sheet is integrally incorporated into the top layer, where this carrier sheet negatively affects the visibility of the underlying decor. For example, it is known to apply a very pure alpha-cellulose paper as a carrier sheet, which becomes almost transparent when incorporated into the top layer, however, to a certain extent compromises the reproduction of the underlying decor. However, the application of such carrier sheet also has advantages. Namely, it allows forming a more uniform, possibly thicker wear-resistant layer on a coated panel, such as, for example, on a laminate floor panel, without porosities or other inclusions occurring when pressing this wear-resistant layer. The present preferred embodiment also allows forming such relatively uniform and thick wear-resistant layer on a coated panel, however, the removability of the film allows excluding at least partially the negative effect of such carrier sheet on the visibility of the underlying decor. The inventors also found that with this manner of applying a thick wear-resistant layer, there is less risk of the occurrence of porosities or other inclusions when pressing it, which in its turn then results in a better transparency of the synthetic material layer.

In the case of said preferred embodiment, said hard particles preferably are situated substantially only on that side of said film which is directed to the decor during the assembly step. In such an arrangement, said structured press element is maximally exempted from contact with the hard particles, which, as aforementioned, may lead to wear at the press element concerned.

Also, in the case of said preferred embodiment, in said step of producing the synthetic material layer, said synthetic material preferably is provided at only one side of said film. Preferably, then it is this respective side of the film which is directed to the decor during the assembly step. In this manner, a maximum smooth transfer of the synthetic material layer can be obtained.

It is noted that according to the invention, it is of course not excluded that said synthetic material layer is at least partially provided by means of a separate carrier sheet, wherein this carrier sheet then indeed is incorporated in the top layer. This may relate, for example, to a paper sheet, such as a so-called overlay. The invention also does not exclude that the synthetic material layer is applied by a combination of techniques, for example, directly on the decor and/or on a separate carrier sheet and/or on said film, by means of immersion techniques and/or spraying techniques and/or roller application techniques and/or spreading techniques. A particular combination is created when the decor is printed on a material sheet, such as a paper sheet, and this printed material sheet as such is provided with synthetic material, and when above this printed material sheet, which is provided with resin, an additional synthetic material layer with hard particles is provided by means of said removable film, said film then preferably relating to a synthetic material film. The synthetic material of the printed material sheet and the synthetic material layer provided there above preferably comprise substantially the same components, with the exception of the hard particles. This may concern, for example, a melamine resin, such as melamine formaldehyde resin.

According to the invention, said film, for the major part thereof or even entirely, is removable from the obtained assembled entity. However, it is not excluded that certain portions of the film are definitively transferred to the assembled entity, where they fulfill, for example, a definitive decorative function or contribute to the protection of the aforementioned decor.

According to the invention, said film, during the step of assembling, covers the major part of the surface of said synthetic material layer or still better at least 80 or even at least 90 percent of this synthetic material layer, such that the risk of wear of the structured press element is practically minimized.

Said film preferably is a non-porous material sheet. In this manner, it is obtained that this film can not absorb synthetic material from the underlying synthetic material layer. Consequently, the possible adherence of the film is minimized and is avoided that synthetic material from the underlying layer vanishes in the film to be removed.

Preferably, the film is a polymer film. For example, polyethylene film or polyester film can be applied as the film. Possibly, such polymer film can be provided with a covering layer, such as a release layer, for example, of silicone. Surprisingly, the inventor has found that such synthetic material film still can be applied as a carrier sheet for a synthetic material, such as a thermo-hardening resin. Contrary to the expectations of the inventors, still a sufficient provisional adherence of the resin, in the case of their experiments, a melamine formaldehyde resin, on the film is obtained, such that the latter could be conveyed without problems up to the press where the assembly step was to be performed. Namely, it was expected that this resin, due to insufficient adherence to the carrier sheet, would begin to drop or slip.

Said film preferably is an at least translucent or transparent material sheet. By such film, the complexity of the methods of the state of the art is influenced only minimally. For example, it remains possible to detect the underlying decor or portions thereof by means of cameras or other optical sensors, such that the usual control of processes, such as appropriate press treatments or providing impressions in so-called register with the printed decor, remains possible.

According to still another preferred embodiment of the method of the invention, said portion of the film, although it is removable, stays present on the decorative top layer in at least a further step of the method. In this manner, the film can remain protecting the surface of the top layer in further manufacturing steps, such that the risk of the occurrence of scratches during this further manufacture practically is excluded. The panels concerned can even be packaged in a stage in which the film is not yet removed. It is evident that, how later the film is removed, the lower the risk of scratches being formed in the top layer. In an ideal case, the film is removed by the end user only after the panels have been set to use, for example, in the case of floor panels, after the floor covering or a part thereof has been installed, or, in the case of furniture panels, after the furniture has been delivered and/or assembled.

Preferably, the method of the invention is applied for manufacturing coated panels with a laminate top layer and still better for coated panels with a laminate top layer obtained by means of a DPL technique. Herein, in said step of assembling, a stack is formed comprising at least a substrate, said decor, said synthetic material layer and said film, wherein the aforementioned press treatment is performed on this stack, as a result of which at least a bond between the decor and said synthetic material layer as well as a bond between said top layer and the substrate is obtained. Preferably, said stack comprises a so-called backing layer or balancing layer at the underside of the substrate. The substrate preferably consists of a wood-based board material, such as particle board, plywood, MDF or HDF.

As a synthetic material in said synthetic material layer preferably a resin, such as a thermo-hardening resin, is applied. Surprisingly, the inventor has found that an amino resin, such as melamine formaldehyde resin, will lead to favorable results, especially in respect to the removability of said film. However, it is not excluded to work with a lacquer, such as an UV or electron beam hardening lacquer. The structured press element applied according to the invention preferably relates to a press plate or press sheet, which typically can be applied in an opening and closing, so-called short-cycle press. However, it is not excluded to work with a structured press belt or press roller, which then rather would be used in a continuous press treatment. Also, so-called structure films are not excluded as press elements. Preferably, however, rigid press elements are used, such as the also above-mentioned press plates, press belts and press rollers. Preferably, press elements are used which substantially consist of metal, such as press elements consisting of a steel and/or copper alloy. Preferably, the structure of the press element is at least partially obtained by means of an etching treatment, whether or not combined with a preceding machining treatment, for example, for forming the deepest-situated structure portions of this press element. Preferably, a press element is applied with only one structured side.

Preferably, the structure, which according to the invention is impressed in the synthetic material layer by means of the press element, corresponds to the underlying decor. So, for example, may the decor represent a wood motif showing wood nerves and/or wood pores, wherein the realized structure then comprises impressions and/or protrusions situated at the height of said wood nerves and/or wood pores, or wherein the realized structure shows impressions and/or protrusions following said wood motif.

It is clear that the invention also relates to coated panels, more particularly floor panels, furniture panels, ceiling panels, wall panels and the like, which are obtained by means of a method with the characteristics of the first aspect or the preferred embodiments thereof.

According to a second independent aspect, the invention relates to a coated panel of the type comprising a substrate and a provided thereon decorative top layer, with the characteristic that said decorative layer comprises hard particles and is at least partially covered with a removable film. Such panel may or may not be obtained by means of the method of the first aspect and may or may not show the further characteristics and features mentioned there.

Due to the fact that the decorative top layer is at least partially covered with a removable film, it is obtained that such panel, before and after being installed, undergoes less risk of damages, such as scratches in the top layer. The coated panel of the invention can also offer the advantage that during the manufacture and further processing of the panel, the hard particles of the decorative layer are at least partially shielded from production installations, such that the wear on these installations can be limited. In this last case, it is, of course, necessary that the protective film is already situated on the coated panel, when this latter is still unfinished and/or not yet packaged.

Preferably, the coated panel or the semi-finished product on which such coated panel is based already comprises said removable film already in an earliest- possible stage of its manufacture, and preferably this film is removed only in a latest-possible stage. Preferably, multiple of such coated panels are packaged together, whereas the removable film still is present on the decorative layer, such that said risk of scratches is also reduced in the wrapping. Preferably, it will be the task of the user of such panels to remove the film. In the case of floor panels, the user even can install one or more of the floor panels before removing the film.

Although the invention can be applied for any kind of decorative layers, such as veneer layers or other wood layers, it preferably relates to coated panels wherein said decorative layer has a printed decor. As also mentioned above, such decor can be provided on the substrate with or without the intermediary of primer layers or can be provided on a material sheet incorporated in the decorative top layer, for example, by means of said DPL or HPL technique.

According to a particular preferred embodiment, said transparent or translucent layer is provided with a structure of impressions and/or protrusions, which may or may not correspond to said possible printed decor. Whether or not in combination with such structure, said transparent or translucent layer may be provided with gloss degree differences, which possibly also correspond to the printed decor.

It is noted that said removable film is very effective for avoiding scratches in glossy decorative layers. By glossy in particular those decorative layers are indicated showing at least in certain portions thereof a gloss degree of at least 10 or even of 20 or more, as measured according to DIN 67530. Such gloss degrees can be obtained, amongst others, by laminate top layers. It is also not excluded that gloss degrees between 60 and 90 units are achieved. Preferably, said decorative top layer comprises a printed decor, as well as a transparent or translucent synthetic material layer, wherein said synthetic material layer extends at least partially above said printed decor. Herein, said hard particles are situated preferably substantially or entirely above said printed decor.

Preferably, said transparent or translucent layer is provided with a structure of impressions and/or protrusions, which may or may not correspond to said printed decor. The best results are obtained when the method is applied for manufacturing coated panels, wherein at least a portion of the hard particles is situated in the synthetic material layer at higher-situated position than any material sheet.

According to a particular preferred embodiment of the second aspect, the coated panel relates to a laminate floor having coupling means at least at one pair of opposite edges, with which coupling means two of such floor panels can be coupled to each other, such that a locking is obtained in a vertical direction perpendicular to the plane of the coupled floor panels, as well as in a horizontal direction to the coupled edges and in the plane of the coupled floor panels. Such laminate floor panel can be offered as a do-it-yourself product, which possibly can be installed by inexperienced users to form a floor covering. It is evident that such removable film preferably is situated at the usage side or decorative side of the floor panel, however, it is not excluded that such film is also situated at the underside of the floor panel. Preferably, the floor panels of this first example relate to floor panels with a laminate top layer, such as a top layer realized on the basis of a DPL technique. In such do-it-yourself products, the presence of a removable protective film offers an additional guarantee for a good result. The protective film also offers advantages to professional users. When installing the floor covering, they can step upon the already installed floor panels without worrying, as a result of which the installation time can be shortened. Also when sawing floor panels to length, the film allows putting the floor panel upside down on the sawing support without any risk of forming scratches.

According to another particular preferred embodiment of the second aspect, the coated panel relates to a furniture panel having recesses at least at one of its flat sides, in which recesses furniture fittings or further furniture panels can be applied. One or more of such coated panels can be offered in a kit with further parts for self combining a piece of furniture. Here, too, the protective film offers an additional guarantee for obtaining a nice undamaged result. It is clear that said removable film preferably is provided at least at that side of the furniture panel which is intended for forming an exterior side of the piece of furniture concerned, although it is not excluded that such film is also or only provided at the interior side. Preferably, the furniture panels of this second example relate to furniture panels with a laminate top layer, such as a top layer realized on the basis of a DPL technique.

It is clear that the invention also relates to a packaging unit comprising two or more of the coated panels, for example, floor panels, with the characteristics of said second aspect or the preferred embodiments thereof. It is also clear that the invention also relates to a semi-finished product for manufacturing a coated panel with the characteristics of said second aspect or the preferred embodiments thereof, wherein this semi-finished product already comprises the removable film.

With the intention of better showing the characteristics of the invention, hereafter, as an example without any limitative character, several preferred embodiments are described, with reference to the accompanying drawings, wherein:

Figure 1 schematically represents several steps in a method according to the invention;

Figure 2, at a larger scale and in cross-section, represents a view on the area indicated by F2 in figure 1 , for an assembled entity obtained by means of the method of figurei ; Figure 3 represents a coated panel with the characteristics of the second aspect of the invention;

Figure 4, at a larger scale, represents a cross-section according to the line

IV-IV indicated in figure 3; and

Figure 5 schematically represents another step in a method according to the invention, for a variant.

Figure 1 represents several steps S0-S1 in a method for manufacturing coated panels 1. Herein, this relates to coated panels 1 comprising a substrate 2, for example, a MDF or HDF panel, upon which at least a top layer 3 is provided.

Figure 2 shows that the top layer 3 of the obtained coated panels 1 comprises at least a decor 4, in this case, a printed decor, and a provided-thereon synthetic material layer 5 with hard particles 6. The coated panel 1 of the example relates to a panel with a laminate top layer 3 obtained on the basis of a DPL technique. Said printed decor 4 is provided on a material sheet 7, namely, a paper sheet, also named decor paper, which is provided with resin and in this manner forms the so- called decor layer 8.

As depicted in figure 1 , the method of the invention comprises at least the step S1 of assembling said top layer 3, wherein at least said decor 4 and said synthetic material layer 5 are provided on top of each other. To this aim, a press treatment by a structured press element 9 is applied. As represented here, this relates to a press treatment applied in a so-called short cycle (German: Kurztakt) press device 10, in which a structured press plate is applied as a press element 9.

The particularity of the method of the present invention consists in that in said step of assembling, a film 11 is situated between the press element 9 and said synthetic material layer 5, wherein a portion of the structure 12 of the press element 9, by the intermediary of said film 11 , is impressed into said synthetic material layer 5. Figure 2 clearly shows that the structure 12 of the press element 9, so to speak, is copied through said film 11 ; at the same time, the film 11 offers a protection of the press plate or the press element 9 against possible wear by the influence of the hard particles 6 present in the synthetic material layer 5. According to the invention, as represented here by arrow 13, at least a portion of said film 11 is removable from the obtained assembled entity 14.

In the case of figure 1, in said step S1 of assembling a stack 15 is formed, which comprises at least said substrate 2, said decor layer 8, said synthetic material layer 5 and said film 11. In this case, the stack 15 also comprises a bottom layer or backing layer 16 at the underside 17 of the substrate 2. Such bottom layer or backing layer 16 may consist, as in the present case, of a paper sheet or another material sheet 7 provided with synthetic material, such as resin 18. It is noted that in the example also the decorative layer 8 is provided with resin 18 and that therefore said synthetic material layer 5 is formed at least partially by the resin 18 of the decorative layer 8, said resin being situated at the surface of the respective material sheet 7 of that decorative layer 8. The press treatment of said assembly step S1 then is performed on this stack 15, whereby, as clearly represented in figure 2, an assembled entity 14 is obtained, which shows at least a bond between the decorative layer 8 and said synthetic material layer 5 as well as a bond between said top layer 3 and the substrate 2.

The method schematically represented in figure 1 shows further particular preferred characteristics. Prior to said step S1 of assembling, the represented method also comprises the step SO of producing said synthetic material layer 5, wherein at least a portion of this synthetic material layer 5 and said hard particles 6 are provided directly or indirectly on said film 11. In this case, this preceding step SO comprises two partial steps A-B, namely a partial step A, in which a suspension 19 of hard particles 6 and resin 18 is applied, and a partial step B, in which resin 18 without hard particles is applied, or at least with less hard particles than said suspension 19. It is clear that said preceding step SO can be performed in any manner and that it does not necessarily have to consist of different partial steps A-B. Preferably, however, the synthetic material layer 5 provided on the film 11 comprises a resin layer 20 enriched with hard particles 6, which is adjacent to the film 11. This resin layer 20 then preferably forms the upper side 21 of the final coated panel 1.

The hard particles 6 and said synthetic material 18, which are provided on the film 11 during said preceding step SO, are situated substantially and in this case only on the side of the film 11 which, during the assembly step S1 , is directed to the decor 4 or the decorative layer 8.

As figure 2 clearly shows, said film 11 is at least partially removable from the assembled entity 14 in that this film 11 comes off from at least a portion of the synthetic material layer originally provided thereon, and in particular from the resin layer 20 enriched with hard particles 6. To this aim, the film 11 , as in this case, can be provided with a release layer 22, such as a silicone layer. It is clear that said film 11 best is removable for the major part thereof, if not entirely, from the obtained assembled entity 14. Of course, it is not excluded that a portion of the synthetic material 18 and/or the hard particles 6 remains present on the removed film 11. Preferably, however, at least 80 percent of the deposited amount of synthetic material 18 and/or hard particles 6 are transferred to the assembled entity 14. According to a variant, the synthetic material 18 of said decor layer 8 can be provided with hard particles 6, too. Such particles 6 are represented in dashed line 23 in figure 2 and preferably have a larger average main dimension than the hard particles 6 applied by means of the film 11.

Figure 2 also represents an example of a coated panel, wherein at least a portion of the hard particles 6-23 is situated higher in the top layer 3 than any material sheet 7. As mentioned in the introduction, when manufacturing such panels, the largest gain in service life of the press element is achieved. To wit, forming a barrier between the press element and the surface of the synthetic material layer is of particular importance with these panels.

Figure 3 represents a laminate floor panel, which can be obtained by means of a method according to the invention and which also shows the characteristics of the second aspect of the present invention. This relates to a rectangular floor panel with a pair of long opposite edges 24-25 and a pair of short opposite edges 26-27.

Figure 4 represents that this floor panel is of the type comprising a substrate 2 and a decorative top layer 3 provided thereon. For obtaining sufficient wear resistance and scratch resistance, such decorative top layer 3 preferably comprises hard particles, however, this is not represented here.

The particularity of the floor panel represented in figures 3 and 4 is that it comprises, in combination with such hard particles 6, a removable film 11 extending at least partially over said decorative top layer 3. The decorative top layer 3 comprises a printed decor 4, more particularly a decor layer 8, as well as a transparent or translucent synthetic material layer 5 extending above said printed decor 4.

Figure 3 clearly shows that the example relates to a floor panel comprising a printed decor with a wood motif. More particularly, this relates to a wood motif representing only a single plank. As aforementioned, by means of the press treatment preferably a structure of impressions and/or protrusions is obtained, which corresponds to this motif. Realizing, in the synthetic material layer, structures corresponding to a printed motif by means of a press plate is known as such, for example, from WO 01/96689.

As becomes clear from figure 4, the laminate floor panel concerned is having coupling means 28 at least at one pair of opposite edges 24-25, and still better, as it is the case here, at both opposite edges 26-27, with which coupling means two of such floor panels can be coupled to each other. In this case, this relates to coupling means 28 known as such from WO 97/47834. More particularly, they allow obtaining a locking between two of such floor panels in a vertical direction V1 perpendicular to the plane of the coupled floor panels, as well as in a horizontal direction H1 perpendicular to the respective coupled edges 24-25 or 26-27 and in the plane of the floor panels.

At the long pair of opposite edges 24-25, the floor panel of figure 4 has chamfers 29 in the form of a bevel. For laminate floor panels, such bevels are known from WO 01/96688. Said film 11 may or may not be provided over this bevel, too, or may extend there above, such as here. Generally, it is convenient for removing the film 11 when it extends with a portion up to beyond the edge 30 of the actual top layer 3 and still better up to beyond the upper edge 31 of the floor panel.

It is clear that floor panels fulfilling the characteristics of the invention do not necessarily have to be provided with chamfers 29 or bevels at least at two opposite edges 24-25. They may also have straight opposite edges, which, when two of such floor panels are coupled to each other, join against each other or virtually against each other at the height of the respective top layers 3.

The bevels or chamfers 29 from the example of figure 4 are formed by removing a material portion next to the respective upper edge 31, wherein a separate decorative layer is provided on the thus formed surface, for example, a lacquer layer or a print layer. However, it is not excluded that such bevels or chamfers 29 are formed by means of the structured press element 9. In such case, the decor of the actual surface of the panel 1 merges into the surface of the chamfer 29. According to the invention, the structure of the structured press element 9 may also be restricted or substantially restricted to structure parts intended for forming chamfers or other joints, such as imitations of cement joints, at the edge or at the surface of the panels 1. According to the invention, it is also possible that the structure of the structured press element 9 is restricted or substantially restricted to structure parts intended for realizing areas of mutually differing gloss degree in the surface of the synthetic material layer.

It is clear that the structure of the press element according to the invention principally can be any structure. Preferably, such structure comprises at least structure parts with which in the surface of said synthetic material layer a structure of impressions and/or protrusions can be formed, which imitates the relief of wood or stone. For example, one may work with structure parts, the obtained relief of which imitates wood pores and/or wood nerves. Preferably, the structure, as already mentioned above, comprises at least structure parts with which in the surface of said synthetic material layer a structure of impressions and/or protrusions can be formed, which imitate or form lowered edges. Still other possibilities are structure parts, the obtained relief of which in the synthetic material layer imitates removed material portions, such as it may be the case when imitating scraped wood.

Generally, it is noted that bevels or chamfers 29 also can be provided by means of a separate press treatment after the press treatment, which, amongst others, is mentioned in the first aspect of the invention, already has been performed.

Figure 5 represents another variant for the step of assembling mentioned in connection with the method of the first aspect. Herein, the film 11 is supplied to the press device 10 as a material web 32. This may be performed, as in the example, from a roll 33. After finishing said assembly step S1 , this film 11 either may be directly removed from the assembled entity 14 and, for example, be rolled up again, or may remain present on the assembled entity 14 for a certain time. In this last case, the film 11 can be cut off with each assembly in order to separate it from the roll 33.

By means of the variation of figure 5, it is also possible to apply said film 11 several times or to re-use it. In such case, the film 11 preferably is not applied as a carrier sheet for a portion of the synthetic material layer 5. Instead of this, in the example a previously produced portion of the synthetic material layer 5 is used, which is provided on a separate material sheet 7A, wherein this material sheet 7A, for example, paper sheet, will be incorporated in the top layer 3 of the final coated panel 1 during the assembly step S1. Re-using said film 11 may be performed, for example, by shifting it per assembly over a distance which is smaller than the distance to be pressed or by not refreshing it during a number of assembly steps. When the film 11 is refreshed during each assembly step and is rolled up again, the respective roll with film can also- be applied several times for supplying film 11 to the press device 10.

Finally, it is noted in connection with figure 5 that the portion of the synthetic material layer 5 which is provided on the separate material sheet 7A, shows a resin layer 34-35 in the core of the paper sheet as well as at the surfaces of the paper sheet. Herein, in both superficial synthetic material layers 34-35 hard particles 6, such as aluminum oxide, are present, wherein the hard particles 6 of the resin layer 34 situated most distant from the printed decor 4 have a smaller average main dimension than the hard particles 6 of the resin layer 35 situated closest to the printed decor 4. For said separate material sheet 7A, preferably a more light-weight paper is applied than for said decor layer 8. For this separate material sheet 7A, for example, a paper sheet can be applied with a weight between 15 and 30 grams per square meter, whereas for the decor layer 8 preferably a paper sheet with a weight between 50 and 100 grams per square meter is applied. It is clear that, also in the case of the example of figure 5, at least a portion of the hard particles is situated at a position in the top layer 3 which is situated higher than any material sheet 7-7A, wherein a resin layer 20 enriched with hard particles 6 is obtained at the surface of the final panel 1.

It is clear that the assembled entity 14 obtained according to the invention as a result of the assembly step does not necessarily have the dimensions of the final coated panel 1. To wit, the method of the invention still may comprise steps in which such assembled entity is divided into smaller panels. When performing such step, said film 11 preferably remains present, because in a dividing operation, such as during sawing, a lot of dust may be created, which may lead to the formation of scratches at the surface of an exposed top layer. Also during the possible provision of edge finishing treatments at coated panels, such as when providing coupling means in the case of floor panels, said film 11 preferably remains present on the panel. According to the state of the art, during the milling of coupling means, glossy traces may be formed on the surface of the top layer, as these floor panels according to the state of the art are transported through the milling machine at high speed while being pressed with their decorative side on so-called pressure or gliding shoes. However, when the removable film of the present invention is present on this decorative side when milling the coupling means, such glossy traces can be avoided and the wear of the milling machine or the parts thereof can be restricted, too. In particular, the wear of pressure or sliding shoes can be restricted.

In general, it is noted in respect to the figures that the thickness of the layers represented there is indicated only schematically and does not include a predefinition in respect to their absolute or relative thickness.

With reference to figures 1 and 5, it is also noted that it may be advantageous to apply perforations in the press element 9. By such perforations, air inclusions trapped between the film 11 and the press element 9 can escape, such that the risk of a possible formation of porosities or other surface defects in the synthetic material layer 5 can be avoided as much as possible. Here, this may relate to perforations which are concentrated in so-called technical zones of the press element and/or to perforations provided in actually operative zones of the press element. By technical zones, the zones are indicated which are active on a portion of the synthetic material layer intended for being removed during a treatment following the press treatment, such as during a dividing operation or milling operation. By the actually operative zones, the zones are indicated which are active on the portions of the synthetic material layers intended for being present in the final coated panel. Perforations provided in the actually operative zones preferably show a limited diameter, such as a diameter of less than 0.5 millimeters or even of less than 0.2 millimeters. Such perforations can be provided, for example, by means of a laser treatment or by means of a conventional bore treatment. Perforations provided in the technical zones may have a larger diameter, however, preferably remain limited to a diameter of maximum 2 mm. By means of such larger perforations in the technical zone, a concentration of surface defects in the corresponding zone of the synthetic material layer can be obtained, whereas in the remaining parts of the synthetic material layer such defects are avoided as much as possible.

It is noted that the invention in an independent manner also relates to such perforated press element, whether or not it is applied in a method according to the first aspect. Namely, such press element may also be advantageous when no film is applied between the press element and the laminate surface, or when one does not work with a structured press element. Of course, it is possible that such perforations are provided only in the zones where difficulties with air inclusions or other difficulties occur or are predicted. For example, such perforations can be provided in zones which are intended for forming the deeper-situated relief portions of the synthetic material surface. It is clear that such perforations may have any shape. Preferably, however, they are made cylindrically. The invention does not include any restriction in respect to the number of such perforations or their distribution over the surface of the press element. Preferably, however, they are provided in groups of ten or more. It is noted that, except beneficial effects for avoiding air inclusions, by means of such perforations also particular surface structures can be achieved at the surface of the synthetic material layer.

Further it is noted, with reference to figures 1 and 5, that the sequence of the different layers 3, 2, 16 in the stack 15 of course also can be composed upside down, wherein the press element 9 then is situated underneath the formed stack 15 in the press device. This inverted stacking may have advantages in respect to avoiding air inclusions, as the film 11 already is pressed against the structured press element by its own weight.

According to a third independent aspect, the present invention also relates to an alternative method for forming coated panels, which allows obtaining similar advantages as discussed in connection with the aforementioned first aspect. To this aim, the invention relates to a method for manufacturing coated panels, wherein these panels are of the type comprising a substrate and a top layer provided thereon and wherein the top layer comprises at least a decor and a provided thereon synthetic material layer with hard particles, wherein the method comprises at least the step of assembling said top layer, wherein at least said decor and said synthetic material layer are provided on top of each other by means of a press treatment by means of a press element, the latter whether or not being structured, characterized in that the press element prior to said press treatment is provided with a covering layer based on a synthetic material. Preferably, this as such relates to a press element substantially consisting of a steel and/or copper alloy. Preferably, it relates to a rigid press element, such as a press plate. Said covering layer preferably comprises silicone and/or polytetrafluor ethylene (PTFE) and/or polyethylene and/or polyvinyl chloride and/or polyester and/or polypyrol. Preferably, the covering layer is provided on the press element in liquid form, where it preferably hardens to form a continuous or virtually continuous layer. However, it is not excluded that the covering layer is selectively applied on the parts of the press element where it is most desirable. Preferably, the application takes place in the press element itself, for example, by means of an application system, which is brought into the press device prior to the press treatment. This may relate to a preferably contact-free application system, which sprays, sputters or atomizes. However, it is not excluded that application systems with one or more rollers or doctor blades are used. Preferably, the respective covering layer is renewed after one or more press treatments, after the remainders thereof have been entirely or partially removed or not. Preferably, a covering layer is applied having a thickness of less than 100 μm and still better smaller than 60 μm. Good values for the thickness of the covering layer are between 5 and 35 μm. It is preferred that the respective covering layer after said press treatment remains partially, and preferably entirely, present on the press element; however, it is not excluded that it is partially transferred to the synthetic material layer, where it possibly may offer advantageous effects. For example, it may contribute to the scratch resistance of the obtained surface. It is clear that as hard particles in the surface layer of the panel, the same panels can be applied as mentioned in connection with the first aspect of the invention.

It is clear that such covering layer has many advantages in common with the film mentioned in the first aspect. For example, it also forms a barrier between said particles and the press element. By the choice of the covering layer, the obtained gloss degree can be determined. By means of such covering layer, the complexity of the methods from the state of the art is influenced only to a minor degree.

Also, it is clear that the assembled entity or panel to be manufactured or obtained can show the same features as it was the case in the first aspect, inasmuch these are not contradictory, and that steps preceding or following said press treatment can be performed in an analogous manner.

The present invention is in no way limited to the above-described embodiments; on the contrary, such methods and coated panels can be realized according to various variants, without leaving the scope of the present invention.

Claims

Claims.

1.- Method for manufactaringr coated panels, wherein these panels (1) are of the type comprising a substrate (2) and a top layer (3) provided thereon, and wherein the top layer (3) comprises at least a decor (4) and, provided thereover, a synthetic material layer (5) with hard particles (6), wherein the method comprises at least the step (S1) of assembling said top layer (3), wherein at least said decor (4) and said synthetic material layer (5) are provided on top of each other by means of a press treatment by a structured press element (9), and wherein said synthetic material layer (5) at the surface of the panel (1) comprises a resin layer (20) enriched with said particles (9), characterized in that in said step (S1) of assembling, a film (11) is situated between the press element (9) and said synthetic material layer (5), wherein a portion of the structure (12) of said press element (9) is impressed into said synthetic material layer (5) by the intermediary of said film (11) and at least a portion of said film (11) is removable from the obtained assembled entity (14). i

2.- Method according to claim 1 , characterized in that said decor (4) relates to a printed decor.

3.- Method according to claim 1 or 2, characterized in that the method, prior to said step (S1) of assembling, further comprises at least the step (SO) of producing said synthetic material layer (5), wherein at least a portion of said synthetic material layer (5) and said particles (6) are provided on said film (11), wherein said film (11) then is at least partially removable from the obtained assembled entity (14) in that it comes off from at least a portion of said synthetic material layer (5).

4.- Method according to claim 3, characterized in that said hard particles (6) are situated substantially only on the side of said film (11) directed towards the decor (4) during the assembly step (S1).

5.- Method according to any of the claims 3 or 4, characterized in that during said step (SO) of producing the synthetic material layer (5), said synthetic material (18) is provided substantially on only one side of said film (11 ).

6.- Method according to any of the preceding claims, characterized in that said film (11), for the major part thereof or even entirely, is removable from the obtained assembled entity (14).

7.- Method according to any of the preceding claims, characterized in that said film (11) is a non-porous, preferably translucent material sheet, such as a film of polyethylene.

8.- Method according to any of the preceding claims, characterized in that said portion of the film (11), although it is removable, remains present on the top layer (3) in at least a further step of the method.

9.- Method according to any of the preceding claims, characterized in that in said step (S1) of assembling, a stack (15) is formed comprising at least a substrate (2), said decor (4), said synthetic material layer (5) and said film (11), wherein the aforementioned press treatment is performed on this stack (15), as a result of which at least a bond between the decor (4) and said synthetic material layer (5) as well as a bond between said top layer (3) and the substrate (2) is obtained.

10.- Coated panel of the type comprising a substrate (2) and a decorative top layer (3) provided thereon, characterized in that said decorative layer (8) comprises hard particles (6) and is at least partially covered by a removable film (11).

11.- Coated panel according to claim 10, characterized in that said decorative top layer (3) comprises a printed decor (4), as well as a transparent or translucent synthetic material layer (5), wherein said synthetic material layer (5) extends at least partially above said printed decor (4).

12.- Coated panel according to claim 11 , characterized in that said transparent or translucent layer (5) is provided with a structure of impressions and/or protrusions, which may or may not correspond to said printed decor (4).

13.- Coated panel according to any of the claims 10 to 12, characterized in that the coated panel (1) relates to a laminate floor panel comprising coupling means

(28) at least at one pair of opposite edges (24-25), with which coupling means two of such floor panels can be coupled to each other, such that a locking is obtained in a vertical direction (V1) perpendicular to the plane of the coupled floor panels, as well as in a horizontal direction (H1) perpendicular to the coupled edges (24-25) and in the plane of the coupled floor panels.

14.- Coated panel according to any of the claims 10 to 13, characterized in that the coated panel relates to a furniture panel having, at least at one of its flat sides, recesses in which furniture fittings or further furniture panels can be provided.

15.- Coated panel, characterized in that it is obtained by means of a method according to any of the claims 1 to 9 and wherein this coated panel does or does not show the characteristics of any of the claims 10 to 14.