CN105835589B - Method for manufacturing a panel and floor panel obtained by the method - Google Patents

Abstract

The invention provides a method of manufacturing a coated panel (1) of the type comprising at least a substrate (2) and a top layer (3) with a motif, said top layer being provided on this substrate (2), wherein the method of manufacturing the top layer (3) comprises at least two steps, namely a first step (S4) of providing a synthetic material layer (7) on the substrate (2) and a second subsequent step (S5) of providing a relief on the surface of said synthetic material layer (7), wherein said relief comprises a pattern of grooves and/or projections, wherein the relief is at least partly obtained by locally increasing and/or decreasing the volume of said top layer and/or substrate, wherein said pattern is at least partly determined by printing an expansible, expansion-promoting or anti-expanding agent.

Description

Method for manufacturing a panel and floor panel obtained by the method

The present application is a divisional application of patent applications with PCT international application numbers PCT/IB2009/055148, application dates 2009, 11/18, chinese application number 2000980151432.X, entitled "method for manufacturing sheet material" in the chinese national phase at 20/6/2011, and the entire contents of which are incorporated herein by reference.

According to U.S. code 119(e), this application claims the benefit of U.S. provisional application No.61/139,286 filed on 19/12/2008.

Technical Field

The present invention relates to a method for manufacturing a panel, and to a panel obtainable by such a method.

The invention relates in particular to a method in which one or more material layers are provided on a substrate, wherein at least one of the material layers comprises a printed motif, preferably this relates to a motif which is at least partly obtained by means of printing (print) which is carried out directly or indirectly on the substrate, however, the invention also applies to panels in which the motif is realized in another way, for example by means of printing the motif on a carrier plate and providing the carrier plate on the aforementioned substrate, in which case for example a laminate is laminated with DP L (direct lamination).

Background

Such sheets are known, for example, from US 1,971,067, US 3,173,804, US 3,554,827, US 3,811,915, WO 01/48333, WO 01/47724, US 2004/0026017, WO 2004/042168, EP 1872959, DE 19725829C 1 or DE 19532819 Al. It is also known from the aforementioned documents that the aforementioned material layers may comprise one or more primer layers, wherein these primer layers extend substantially below the printing, and/or may comprise one or more finishing layers, which extend substantially above the motif. Such a finishing layer may comprise, for example, a transparent or translucent synthetic material layer which forms a protective layer over the motif, whether printed or not, and may comprise, for example, wear-resistant particles (e.g. alumina). It is not excluded that the protective layer comprises a sheet of material, such as a paper sheet, containing, for example, a synthetic material, such as an amino resin.

Various methods of providing structure to the surface of coated panels are also known from the aforementioned patent documents. It is known from document WO 2004/042168 to provide grooves in the substrate itself or in the primer layer and to carry out printing in the form of a motif on the structured substrate. It is known from WO 01/47725, US 3,811,915 and US 3,554,827 to provide paint guards on printed motifs to selectively cure a layer of clear paint subsequently provided thereon to form a structure on the final panel. It is known from WO 01/48333 to provide indentations in a lacquer layer arranged on top of a pattern by means of a mould or an impression cylinder. It is known from WO 01/47724 to provide a transparent lacquer layer by selective ink-jetting over a motif and to realize a structure in this way, wherein the lacquer layer thus provided only partially covers the motif, and a part of the motif is unprotected from abrasion. It is known from DE 19725829C 1 to provide indentations in a protective layer applied over a pattern by means of a mould or an impression cylinder or a platen. In DE 19725829 Cl, i.e. a protective layer applied in liquid form is used, which comprises a thermosetting resin (e.g. melamine).

The techniques mentioned above have many deficiencies with respect to flexibility and/or with respect to the structures to be implemented. For example, it is difficult to realize structures corresponding to the patterns provided by printing in a smooth manner with these techniques. Furthermore, according to some known techniques, the motif remains partially unprotected against, for example, wear or moisture penetration.

Disclosure of Invention

According to its various independent aspects, the present invention is particularly intended to provide alternative methods of manufacturing coated panels of the type mentioned above, according to various preferred embodiments of which it is possible to carry out and/or provide remedies for one or more of the drawbacks of the state of the art methods, more smoothly and/or economically than those of the state of the art methods.

For this purpose, according to a first independent aspect thereof, the invention relates to a method for manufacturing a coated panel of the type comprising at least a substrate and a top layer with a motif, said top layer being provided on said substrate, wherein the method for realizing the top layer comprises at least two steps, namely a first step, in which a synthetic material layer is provided on the substrate, and a second subsequent step, in which a relief is provided on the surface of said synthetic material layer, characterized in that said relief comprises a pattern of recesses and/or projections, wherein this pattern is at least partially determined by one or more prints. It is noted that there may be further material layers between the substrate and said synthetic material layer (for example a layer showing at least a part of said pattern or the entire pattern).

It is clear that according to this first aspect of the invention the relief is obtained only after the respective portions of the synthetic material layer have been provided. Thus, for applying the synthetic material layer itself, a technique suitable for coating a flat substrate can be chosen, which greatly simplifies the method, thus suppressing or even eliminating the risk of forming unwanted impurities (e.g. tramp gases) in the synthetic material layer.

Due to the fact that the pattern of the relief is at least partly determined by printing, the structure or relief corresponding to the motif can be applied more simply, smoothly and flexibly. For example, the same printing techniques may be applied to form the motif and to form the one or more prints, such that similar definition may be achieved in the motif and in the corresponding portions of the relief. Preferably, printing by digital printing techniques (e.g. inkjet printing) is applied. Of course, the application of printing techniques such as offset or gravure printing, carried out by means of, for example, impression cylinders, is not excluded.

It should be noted that the color and/or tint of the one or more prints responsible for the respective portion of the structure or relief may remain visible on the decorative side of the final coated panel. In the case of wood structures, in which the wood pores are imitated by a groove structure, the color and/or tint of the wood pores can be achieved in this way.

In practice, the method of the first aspect may be implemented in various possible ways. Four possible methods are discussed below.

According to a first possibility, use is made of printing in a step located below the synthetic material layer and carried out, for example, before or simultaneously with the first step. For example, the printing can be carried out by means of a swelling agent which then, according to the invention, after application of the synthetic material layer, swells during said second step and in this way deforms the synthetic material layer provided thereon.

During expansion, the synthetic material layer may still be soft or have been fully or only partially cured. When a layer of a synthetic material that is not completely cured is used, it can also be cured at the same time as the formation of the structure.

The expansion of the print can be caused, for example, by heating by means of an oven or radiation. The expansion can be limited by mechanical shaping elements in contact with the synthetic material layer, so that a well-defined structure can be achieved, which exhibits fewer and/or smaller rounded portions than otherwise. The use of such a shaping element can be useful, for example, for forming a chamfer (chamfer) at one or more edges of the mentioned sheet material.

Instead of printing with an expanding agent, according to the first possibility, printing can also be performed with an anti-expanding agent, wherein such an agent locally hinders the overall desired expansion. This embodiment is useful when an integral planar structure has to be formed, which requires that the grooves are only shown on a limited surface. This may be the case, for example, when imitating wood structures, in which wood pores are present as recesses in the overall planar structure. Another example of this is the formation of joints or chamfers.

In particular, for example, as an anti-swelling agent, for example, a formulation comprising benzotriazole and/or tolyltriazole may be applied. Such products are capable of reducing or preventing the swelling of synthetic materials, such as PVC. As expanding agent, use may be made of formulations which likewise contain PVC.

According to a subsidiary possibility of said first possibility, the printing of said determinate structure is not only underneath said synthetic material layer, but also underneath said motif. According to this possibility, the motif itself acquires a structure and a depth effect can be achieved.

According to another subsidiary possibility of said first possibility, an expanding or anti-expanding agent is located in the motif and/or forms part of the motif. For example, such formulations can be applied to realize the portions of the motif, i.e. the portions intended to present projections, respectively recesses, on the surface of the coated panel. Thus, the wood veins and/or wood pores of the wood motif can be printed with a colorant or ink containing an anti-swelling agent.

According to a second possibility, a printing is used which is located on top of the synthetic material layer and which will be provided, for example, in a step subsequent to the first step. The printing can be carried out, for example, with a formulation which is capable of forming recesses in the surface of the synthetic material layer, whether or not after activation thereof. For example, a formulation may be selected that, upon activation thereof, may locally dissolve, corrode, burn, melt, or soften the synthetic material layer, so that, at the location of printing, a recess may be formed in the synthetic material layer, possibly after rinsing or otherwise removing the affected portion of the synthetic material layer.

According to another example of this second possibility, the printing can be carried out with a formulation which is capable of forming a relief on the surface of the synthetic material layer, whether or not after its activation. This is achieved, for example, because the printing itself already has a certain thickness and adheres to the synthetic material layer, or because the printing comprises agents which locally cause swelling of the synthetic material or can suppress such swelling. In this case, this can be carried out in a similar manner to the method in the first possibility, but with the difference that the respective expandable or expansion-preventing agent is now located on top of the synthetic material layer.

According to a third possibility of the first aspect of the invention, the printing is used to form structures on a transfer element or embossing element (e.g. a pressure roller), wherein the transfer element thus at least partially structured is then used to form recesses in the synthetic material layer. Preferably, the formation of said structures on the transfer element is carried out simultaneously and/or sequentially with the formation of the recesses in the synthetic material layer. Preferably, the printed formulation itself forms the structure of the transfer element. For this purpose, for example, waxes or lacquers can be used; while the use of formulations containing metals such as zinc or tin is not excluded.

According to a fourth possibility of the first aspect of the invention, the printing is used to form a mask on, in or under the synthetic material layer, wherein the mask is capable of being selectively treated with a synthetic material layer by means of a material removal process and/or a material deposition process, such that the mask determines the pattern of recesses and/or projections thus obtained. Prior to the selective treatment, a selective curing treatment may take place with the aid of the same mask or parts thereof. For example, a selective uv or electron beam curing of a lacquer layer or other synthetic material layer can be obtained in a smooth manner by means of a mask. After this treatment has been carried out, the less cured parts of the mask and the synthetic material layer may or may not be removed by any material removal technique suitable for this, for example a technique of brushing and/or blotting off the mask (possibly together with the uncured parts of the synthetic material layer). According to a preferred embodiment of this fourth possibility, the example mentioned also in the fourth aspect of the invention is obtained. According to a subsidiary possibility of this fourth possibility, the mask is formed by carrying out said printing on a separate foil or web or sheet of material, wherein the foil is preferably made substantially transparent or translucent. When the foil is used between the synthetic material layer to be cured and the radiation source, the foil with the printing can be used, for example, to selectively block ultraviolet or electron radiation. It is clear that in the above, by transparent or translucent is meant that these parts of the foil are transparent to the radiation applied when curing the synthetic material layer.

It should be noted that a method such as in the third possibility of the first aspect mentioned above, wherein the step of forming the structure of the mechanical embossing element is performed sequentially and/or simultaneously with the step of forming the grooves in the surface of the sheet material, thus forms a second independent inventive aspect of the present invention, wherein the structure of the embossing element is then obtained by printing or not. Such a stamp element can be embodied, for example, as a belt, cylinder or plate and can consist essentially of metal (for example a steel alloy or a copper alloy) or of a synthetic material (for example silicone or melamine resin). Instead of by means of printing, the structure may be formed, for example, by material growth techniques or material deposition techniques, such as selective laser melting or sintering, stereolithography, cladding, etc. According to another possibility, a material removal technique can also be used, wherein then preferably a layer of renewable material provided on the stamp element is used, so that the structure of the stamp element can be produced several times. According to another possibility, each stamping element comprises a mechanism allowing its surface structure to be modified. This possibility is particularly useful for forming larger indentations, such as knuckle, chamfer or beveled indentations. By "simultaneously and/or sequentially" is meant that the stamping elements on which the respective structures are formed are preferably also used at the same time, at least in part, to form a relief on the surface of the sheet material.

It is clear that the method of said second independent inventive aspect can be defined as a method of manufacturing a coated panel of the type comprising at least a substrate and a top layer with a motif, said top layer being provided on the substrate, wherein the method comprises at least a step of providing a synthetic material layer on the substrate and a step of providing a relief in the synthetic material by means of a structured mechanical embossing element, characterized in that the steps of forming the structure of the embossing element and providing the relief in the synthetic material are performed sequentially and/or simultaneously. Preferably, when providing the relief in the synthetic material, another structural part of the stamp element is applied, instead of the structural part formed simultaneously on the stamp element. Preferably, a mechanical embossing element in the form of a belt or web is used, wherein the embossing element preferably performs a continuous action, for example, in that the embossing element is transported along a roller (e.g. a press roller). The belt or web has the advantages: which has a surface much larger than the surface of the coated sheet. This allows a sufficiently large distance to be maintained between the location where the structural part is formed and the location where the other structural part is brought into contact with the synthetic material layer.

The step of providing the relief in the synthetic material may be carried out in various possible ways. According to a first possibility, the synthetic material is provided on the board before the relief is realized in the synthetic material layer. According to a second possibility, the synthetic material can also be provided with a relief before the sheet is provided on the synthetic material layer thus structured. Thus, for example, it is possible to provide a synthetic material layer on an already structured part of the stamp element and to place or transfer the synthetic material layer thus formed onto the sheet material. For example, the method known from document WO 2007/059967 can be used essentially. In the method of the international patent application, a lacquer layer is provided on a structured material web, after which the synthetic material layer thus formed is transferred to a panel, wherein the previously structured material web is used. In accordance with the present aspects, instead of using the previously structured web of material, a sequentially and/or simultaneously structured web of material may also be used.

According to the invention, the structure portions formed sequentially and/or simultaneously can be used one or more times in order to provide the synthetic material with a relief. It is also possible, in the case of repeated use of the stamp element, to form the structure part again after it has been used to form the relief of one or more sheets. Furthermore, it is possible that the stamping element may be single-use.

The method having the features of the second aspect generally has the following advantages: a wide variety of embossments can be made with the same imprinting member. Furthermore, it is possible to smoothly switch between different desired configurations.

According to a third independent aspect thereof, the present invention relates to a method for manufacturing a coated panel of the type comprising at least a substrate and a top layer with a motif, said top layer being provided on this substrate, wherein the method for realizing the top layer comprises at least two steps, namely a first step, in which a synthetic material layer is provided on the substrate, and a second subsequent step, in which a relief is provided on the surface of said synthetic material layer, characterized in that said relief comprises a pattern of grooves and/or projections, wherein this pattern is at least partly obtained by locally increasing and/or decreasing the volume of said top layer and/or substrate.

By "locally" is meant that the volume of the entire top layer does not increase and/or decrease uniformly. Here, this may involve very limited local changes of volume increase and/or decrease. For example, a seemingly uniform volume increase may occur over the surface of the top layer as a whole, while a local smaller volume increase or even a volume decrease may occur over the edges to form lower-lying edges, which may serve, for example, as a lacquer layer imitating a knuckle, chamfer or depression. According to another example, a globally seemingly uniform volume increase may occur at the surface of the top layer, while a local lesser volume increase or volume decrease may occur to form grooves which mimic the appearance of wood pores or other local non-uniformities.

It is clear that according to the third aspect of the invention, the relief is obtained only after the respective portions of the synthetic material layer have been provided. Thus, for applying the synthetic material layer itself, a technique suitable for coating a planar substrate can be chosen, which greatly simplifies the method and limits or even eliminates the risk of forming unwanted impurities (e.g. tramp gases) in the synthetic material layer.

Furthermore, it is clear that the mentioned possibilities in connection with the first aspect (application of a swelling or expansion-preventing agent) also form an example of this third independent aspect. The formulation may be provided on the board in any manner, whether by printing or not.

The volume increase of the third aspect may be achieved in any manner. For example, it can take place as a result of a chemical reaction in which gaseous species are formed in the top layer, so that the volume produced is greater than the actual volume of the top layer.

Preferably, the volume increase relates at least to the volume increase of the synthetic material layer. Preferably, the synthetic material layer is positioned on top of said motif and is made transparent or translucent. Preferably, the synthetic material layer forms the upper side of the coated panel. However, it is also possible that there are still other finishing layers on the synthetic material layer, for example one or more lacquer layers, whether or not containing hard particles (for example aluminium oxide particles). It is clear that according to the invention, the synthetic material layer can also be located below the motif or can form part of the motif, wherein the layer can thus display any color.

According to a preferred embodiment of the third aspect, said volume increase or decrease is carried out in a controlled manner, for example in that it is carried out for a mould (for example for a structured planar stamp plate or any other structured stamp element) wherein the structure of the stamp element relates to a portion opposite or approximately opposite to a portion of a relief realized on the surface of one or more respective coated sheets.

According to another preferred embodiment of the third aspect, the relief formed by volume reduction or increase is done with a material removal technique and/or a material addition technique, such as laser milling or stereolithography.

According to the third aspect, it is also possible that the volume increase or decrease itself occurs at the surface of the substrate. This embodiment may be achieved, for example, because the expandable material is present at or in the surface of the substrate. For example, the wood fibres in the layer at the surface of the MDF or HDF board may have an expandable material. According to a slight variant of the third aspect, it is not necessary to realize the relief after the provision of the synthetic material layer. By means of the inventive MDF/HDF or other wood-based board, many new possibilities for manufacturing boards with structures are effectively created. According to this slight variant, the coated panel can be obtained substantially by, for example, carrying out the following steps in any desired order: for example, according to any of the possibilities described herein for locally expanding or not expanding the synthetic material layer, the wood substrate is locally expanded, a motif is provided, and possibly a protective transparent or translucent layer is provided.

According to a fourth independent aspect, the invention relates to a method for manufacturing a coated panel of the type comprising at least a substrate and a top layer with a motif, said top layer being provided on this substrate, wherein the method for realizing the top layer comprises at least two steps, namely a first step of providing a synthetic material layer on the substrate and a second subsequent step of providing a relief on the surface of said synthetic material layer, characterized in that said relief comprises a pattern of recesses and/or projections, wherein this pattern is at least partially obtained by providing a mask on said synthetic material layer and subsequently performing a material removal treatment and/or a material deposition treatment on said synthetic material layer, wherein said mask at least partially determines said pattern.

Applying a mask to selectively add material to and/or remove material from the synthetic material layer gives rise to new possibilities of achieving a relief on the surface of the coated panel. For applying the mask, a printing technique (e.g. inkjet printing) may be used, wherein the features of said first aspect of the invention (more particularly the fourth possibility of the first aspect) may also be obtained. Preferably, as a printing technique, a technique similar to the one used for realizing said motif is applied. In this way, a mask corresponding to the pattern can be realized in a simple manner, which mask can subsequently produce a relief corresponding to the pattern. Preferably, a printing technique is applied that has approximately the same resolution as the printing technique that implements the motif, so that the final relief obtained can be implemented as fine as the motif.

It is clear that according to the fourth aspect of the invention, the relief is obtained only after the respective portion of the synthetic material layer has been applied. Thus, for applying the synthetic material layer itself, a technique suitable for coating a planar substrate can be chosen, which greatly simplifies the method and limits or even eliminates the risk of unwanted impurities (e.g. tramp gases) forming in the synthetic material layer. However, the mask may be provided earlier than the material layer.

Preferably, the mask is composed of a substance resistant to the material removal technique and/or the material deposition technique, so that the respective technique can be truly selectively applied where no openings or openings are present in the mask. The opposite is also possible, i.e. the corresponding technique only works where the mask is present.

As the material removal technique, for example, a chemical etching technique that locally acts on the synthetic material layer, or a chemical etching technique such as sand blasting or shot blasting may be applied. It is also possible for the material removal technique to apply at least a suction treatment. This suction treatment is theoretically suitable when applying a mask or parts thereof for selectively curing the synthetic material layer, wherein preferably the parts of the synthetic material layer located below the masking material are not cured or are cured to a lesser extent.

As a material deposition technique or a material growth technique, for example, stereolithography, or a spray technique, such as an injection molding technique or an immersion technique, may be applied, in which preferably the material will adhere to the places where the mask is not present or open.

According to a fourth aspect, the mask can be removed from the synthetic material layer after the relief has been realized. However, the mask may also remain on the final coated panel and form part of, for example, a final relief or final pattern. As a material deposition technique, a technique can also be applied in which at least the mask is permanently adhered to the synthetic material layer. When the mask must be at least partially retained on the final coated panel, the color of the mask can be tuned to the desired appearance of the decorative side of the final coated panel.

According to the fourth aspect, it is possible that instead of realizing the mask on the plate material, the mask is prepared separately or in other words is implemented as one such existing entity. It is for example possible that the mask comprises or consists of a separate foil, wherein the separate foil or any other separate piece of material is preferably made substantially transparent or translucent, however provided with masking portions for resisting said material removal treatment and/or material deposition treatment, or indeed only for subjecting the synthetic material located underneath the masking portions to these treatments to a greater extent.

According to a specific embodiment, the plurality of masks are provided in an adjacent manner (possibly also one on top of the other). With this embodiment, various relief features are possible. For example, such techniques may be used to achieve deeper and/or three-dimensional structures. This technique also allows the formation of grooves and/or projections having beveled edges and grooves and/or projections having a width to depth ratio and a width to height ratio, respectively, of less than 1 or even less than 0.75 or less.

As can be appreciated from several preferred embodiments of this fourth aspect, it is possible to carry out at least one intermediate step between the first step in which the synthetic material layer is applied and the second step in which the relief is applied at the surface of the synthetic material layer, wherein said synthetic material layer is at least partially cured. Preferably, the curing is carried out selectively and better in a manner determined at least in part by portions of the mask.

As already mentioned above, there may basically be a difference between the two types of masks, i.e. a first type in which the masking portions of the mask resist said material removal treatment and/or material deposition treatment, and a second type in which the masking portions of the mask actually serve to subject the synthetic material located below the masking portions to these treatments to a greater extent. Preferably, this second type of masking portion can be realized by performing the curing of the synthetic material with the same mask, for example by ultraviolet or electron beams or by heating, wherein the masking portion is then preferably used for shielding of the relevant radiation and/or heat. In this way, the less solidified portion can be more subjected to a process (e.g., a material removal process) that must be performed later.

It will be appreciated that the materials used to implement the masking portions of the mask of the fourth aspect must be adapted to the function required for them. For example, wax or paraffin wax may be used.

Preferably, the mask is formed in sequence and/or simultaneously with the step of applying the relief in the synthetic material. Preferably, another masking portion of the mask is applied when forming a relief other than the simultaneously formed relief. Preferably, in case such a mask is used, said mask is implemented as an entity of an existing entity, e.g. a mask in the form of a belt or a web, wherein preferably a continuous movement is implemented, e.g. in that the mask is transported along rollers, e.g. rollers.

It is clear that the invention also relates to a panel obtained according to a method featuring one or more aspects of the invention. Here, this may relate, for example, to a coated panel of the type comprising at least a substrate and a top layer with a printed motif, which top layer is provided on the substrate, wherein the top layer also comprises a transparent or translucent synthetic material layer, which is provided on top of the printed motif, and wherein the synthetic material layer contains a foamable or foamed synthetic material. It will be apparent that such a sheet material may be manufactured by the techniques according to the first and/or third aspects of the present invention.

Preferably, the foamable synthetic material is selected from the series of polyvinyl chloride, polystyrene, polyethylene, polypropylene, acrylates, polyamides, and polyesters. Preferably, said synthetic material layer extends substantially over said entire printed motif.

For the substrate of the coated panel of the present invention, a substrate comprising a wood-based material (e.g., MDF or HDF) is preferably used.

Preferably, the coated panel relates to a panel whose pattern relates to a printed pattern, preferably obtained by performing printing directly or indirectly on said substrate.

It is clear that the coated panel obtained by the process having the characteristics of the invention exhibits, at its surface, a relief obtained by the technique according to one or more of the aspects mentioned above and/or below.

According to another specific fifth independent aspect, the invention relates to a method for manufacturing a coated panel of the type comprising at least a substrate and a top layer with a printed motif, said top layer being provided on the substrate, wherein the method for realizing the top layer comprises at least two steps, namely a first step, in which a synthetic material layer is provided on the substrate, and a second step, in which a relief is provided on the surface of said synthetic material layer, characterized in that said relief comprises a pattern of grooves and/or projections, wherein the pattern is at least partially determined by means of digital techniques. It should be noted that according to this aspect, the second step does not necessarily have to be carried out after the first step, and the synthetic material does not necessarily have to be provided on the substrate at the time when the relief has been achieved on its surface.

It is clear that the printing of the first aspect and the mask of the fourth aspect can be obtained by digital techniques, for example, because they both comprise the printing provided by an ink jet printer. Accordingly, such embodiments of the first and/or fourth aspects also form examples of this particular fifth independent aspect of the invention.

In general, according to this particular aspect, it is preferred to apply digital techniques to provide a mask, whether temporary or not, which defines at least a portion of the pattern, and/or to provide a synthetic-material-resistant, lacquer-resistant, intumescent or anti-intumescent agent, wherein such an agent employed then defines at least a portion of the pattern.

Furthermore, it is clear that the digital technique can also be implemented on a transfer element or a mechanical embossing element, wherein it is preferably implemented simultaneously and/or sequentially with the formation of the relief. In this way, embodiments of the specific second independent aspect already mentioned above can also be obtained.

According to all aspects of the invention, the synthetic material layer preferably extends over substantially the entire surface of the substrate. In this way, a relief or structure can be obtained over the entire surface of the structure. Preferably, the synthetic material layer also extends substantially in the finally formed coated panel over the entire surface of the substrate. Preferably, therefore, the material of the synthetic material layer will also remain present in the deeper structural parts of the top layer. In this way, a good protection of the motif is obtained.

It should be noted that the synthetic material layer mentioned in all aspects of the invention preferably relates to a translucent or transparent synthetic material layer which is located above the motif and in this way protects the motif at least to some extent against wear. In this case, it is possible that the synthetic material layer forms the surface of the final coated panel. However, it is also possible to provide other finishing layers on the respective synthetic material layer, for example uv-curing layers, electron beam curing layers or other lacquer layers, which preferably contain hard particles (for example ceramic particles with an average particle size of less than 200 μm). It is obviously not excluded that the synthetic material layer is situated below the motif and not above or formed by the motif or parts thereof, in which case it is not necessarily translucent or transparent.

For the synthetic material layer itself, synthetic materials containing an amino resin such as melamine resin, PVC (polyvinyl chloride), polyethylene, polypropylene, polyurethane or polystyrene can be used.

Preferably, the method according to all aspects is used for manufacturing a coated panel, wherein the substrate of the panel comprises a wood-based material (e.g. MDF or HDF). Such materials easily have a ground-down upper surface, so that possible irregularities of the respective upper surface do not interfere with the structure or relief achieved at the upper surface. In order to prevent such an influence on the structure, a primer layer containing a filler material by which possible irregularities of the upper surface of the substrate can be filled may be used.

According to any aspect of the invention, when the synthetic material layer (e.g. PVC layer) is combined with a wood based substrate (e.g. MDF or HDF substrate), preferably an adhesion layer is provided between the synthetic material layer and the substrate. The adhesive layer can consist, for example, of a material sheet, which is provided on one side with an amino resin (for example melamine resin) and on the other side with a corresponding synthetic material (for example PVC). Melamine resins are known to adhere well to wood based substrates such as MDF or HDF. It is possible that the pattern has been previously printed on the material sheet.

Preferably, said motif according to all aspects of the invention relates to a printed motif, preferably obtained by performing printing directly or indirectly on said substrate. Direct printing can be obtained, for example, by printing on one or more primer layers already provided on the substrate. However, according to the invention, it is of course not excluded to use a pattern printed on a flexible sheet of material which is then or will be provided in whole or in part on the substrate. Preferably, the motif has been obtained by printing carried out by means of an inkjet printer having one or more print heads.

It is clear that it is possible to carry out the steps discussed in all aspects of the invention on larger sheets, and then to form the final coated sheet, for example by dividing these large sheets with a saw, and to apply the sheet, which already shows the approximate dimensions of the final coated sheet. For a quick reaction of the order and for the elimination of superfluous supplies, it is advantageous to realize the structure and/or the motif as late as possible in the production. In this case, they are preferably provided directly on the board already approximately or completely having the dimensions of the final coated board. In the same case, possible edge modifications, for example milled joining devices or other profiled edge portions, can also be made to the respective sheet material. Of course, it is not excluded to provide the profiled edge portion at a later stage of manufacture. The panels each providing a structure or relief have the following advantages: even when relatively limited structures, e.g. at the edges of the sheet material, are concerned, e.g. with chamfers of less than 1 mm depth, the risk of such structures disappearing (e.g. due to being worn or sawn or otherwise removed) is reduced to a large extent.

Preferably, according to all aspects of the invention, the position of the relief or structure refers to the final edge or final corner point of the coated panel, whether or not this edge still has to be obtained. This preferred embodiment can be implemented in the simplest way when the substrate already has the respective final edge or corner point; however, it is not excluded that the calibration is performed on the final edges or corners to be formed even if the substrate does not have such final edges or corners, e.g. because further reference tools are provided, which take positions called corresponding final edges or corners. For example, the present preferred embodiment allows to favorably obtain a symmetrical structure, such as a tile replica or a floor part replica having two or four lower edges, wherein the width of the lower edges is then preferably implemented equally or approximately equally on opposite sides of the coated board.

It is also clear that, according to all aspects of the invention, a structure corresponding to said motif is preferably obtained.

In general, it should be noted that the relief discussed in all aspects of the invention may also be limited by depth, and thus, in fact, it relates to patterns having different gloss levels. For example, by the technique according to the fourth aspect, in which sandblasting is used as the material removal technique, dull finish can be achieved on the surface of the coated sheet material. Furthermore, it should also be noted that the relief is preferably present touchably at the surface of the final coated panel. However, according to certain embodiments, it is not excluded that the respective relief is present inside the top layer of the coated panel and is not tactile, although visibly present on the surface of the coated panel. This embodiment is obtained by the technique of the invention, giving the relief itself, while the surface of the coated panel is thus made substantially or entirely flat. As previously mentioned, by means of such a relief, a depth effect can be obtained, which remains visible at the surface of the coated panel. Other visible effects (which are present untouchably on the surface of the coated panel) are not excluded.

Drawings

In order to better illustrate the characteristics of the invention, some preferred embodiments are described hereafter, by way of example without any limiting nature, with reference to the accompanying drawings. Wherein:

FIG. 1 schematically illustrates some steps in a method having features of the invention;

FIG. 2 shows a cross-sectional view according to the line II-II shown in FIG. 1 on a larger scale;

FIGS. 3-6 show, on the same scale, cross-sectional views according to the lines III-III, IV-IV, V-V-, VI-VI respectively shown in FIG. 1;

FIG. 7 shows a cross-sectional view according to the line VII-VII shown in FIG. 1 on the same scale but for a variant;

fig. 8 shows a view according to the direction F8 shown in fig. 7 for a variant;

FIG. 9 schematically illustrates another method having features of the present invention;

FIGS. 10 and 11 schematically illustrate further steps in a method having features of the present invention;

FIGS. 12-15 illustrate some further variations of the method having the second aspect method;

FIG. 16 shows another example of a method having features of the fourth aspect of the invention;

figures 17 and 18 show further variants showing the features of the first and fourth aspects.

Detailed Description

Fig. 1 schematically shows some steps S1-S5 in a method of manufacturing a coated panel 1. Each coated panel 1 is of the type comprising at least a substrate 2, for example an MDF or HDF substrate, and a top layer 3 provided on this substrate 2. In this example, the top layer 3 consists of a plurality of material layers 4-7, between which the material layer 5 shows a pattern and is applied during step S2 in the form of a print 8 carried out directly on the substrate 2.

In the preceding step S1, one or more primer layers 4 are provided on the surface of the substrate 2 to be printed with the motif. These layers may have the following purpose: providing a smooth sub-surface (surface) for a subsequently applied material layer 5-8, for example for a material layer 5 with a motif or for a synthetic material layer 7, and/or providing a uniform or quasi-uniform background colour and/or adhesion primer.

Fig. 2 shows the result of step S1 and shows that a possibly uneven surface of the substrate 2 can be made flat or nearly flat by the one or more primer layers 4.

In this example, in step S1, an application technique by means of one or more impression cylinders 9 is used. It is clear that in step S1 of fig. 1, other application techniques may also be used to achieve the primer layer or layers 4. At the same time, it is clear that for the present invention, although important for the quality of the motif, it is not necessary to apply such a primer layer 4. Instead of a primer layer 4 provided in liquid form, a primer layer comprising a sheet of material (e.g. a sheet of paper) may be used, which is provided in dry or semi-dry form on the substrate 2.

As previously mentioned, in step S2 of fig. 1, the motif is realized by means of a print 8 carried out directly on the substrate 2 or on the primer layer 4 already provided on the substrate 2. The obtained pattern relates to a wood pattern extending over the entire length of the rectangular panel 1. Of course, the invention is not limited to this pattern.

In this case, in order to provide the printing motif, an inkjet printer 10 with one or more print heads is used. For example, techniques and devices are available, for example, known from EP 1872959, in which, for example, a set of inkjet printing heads are arranged next to one another, so that the entire surface of the sheet 1 can be covered by multicolor printing. It is clear that the invention is not limited to ink-jet printing techniques, nor to patterns printed directly on the substrate 2, for step S2.

Fig. 3 shows the result of a printing 8 performed directly on the substrate 2, in this case with the primer layer 4 already on top of the substrate 2.

In step S3 of fig. 1, additional printing 6 is provided over the printed motif. This involves printing 6 with an anti-swelling agent. The printing 6 is carried out with a pattern that will determine the final structure or relief of the coated panel 1. Here, the pattern only covers specific locations in the printed pattern and therefore preferably does not extend over the entire surface of the final coated panel 1. In this case the pattern forms a mask which provides the edges of the sheet 1 and certain locations 12 in the surface of the sheet 1 with an anti-swelling agent. The locations 12 in the surface of the panel 1 correspond here to wood flowers or wood veins present in the wood motif and result in grooves appearing in the finished panel 1 which imitate wood pores.

Fig. 4 again clearly shows the positions 11-12 of the print 6 provided in step S3.

In step S3, a print 6 of a defined relief or structure is provided by means of digital printing techniques (for example by means of an inkjet printer 10). It is clear that it is not excluded that the printing 6 or the anti-swelling agent can be applied in other ways.

In step S4 of fig. 1, a synthetic material layer 7 is applied. Such a synthetic material layer 7 preferably comprises a transparent or translucent substance and preferably extends over the entire panel 1 concerned. In this example, an impression cylinder 9 for applying such a material layer is shown. It is, however, clear that the synthetic material layer 7 can be provided in any manner. It is also possible to apply in step S4 a plurality of layers 7 of synthetic material, whether or not they are of the same type, in an up-down arrangement. Preferably, hard wear resistant particles are also provided in the synthetic material layer 7. For example, these particles can be mixed or woven in the synthetic material or synthetic material layer 7 beforehand, or they can be dusted into the synthetic material layer 7 already provided or otherwise placed therein.

Fig. 5 shows the result obtained after step S4.

In step S5 of fig. 1, a relief is provided to the surface of the synthetic material layer 7 applied in step S4.

Fig. 6 shows that a coated panel 1 is obtained which exhibits on its surface a pattern of recesses 13 and protrusions 14, wherein the pattern is at least partly determined by the printing 6 with the expansion-preventing agent applied in step S3. Such a structure is obtained in which the synthetic material layer 7 is activated and starts to expand in step S5. This activation can be achieved by heating the synthetic material layer 7, for example, with a hot-air furnace 15, an infrared furnace or thermal radiation, such as ultraviolet or electron radiation.

Fig. 6 shows that where the expansion preventing agent or the expansion reducing agent is applied in step S3, the expansion occurs to a lesser extent or not at all. In those places there are recesses 13 in the surface of the thickened synthetic material layer 7. In this way, in this example, a chamfer (chamfer)16 has been obtained at the edge 11 of the coated panel 1, and a groove 13 for imitating a wood hole 17 has been obtained in the surface of the panel 1. It is clear that the technique of the invention can also be used to obtain only chamfers 16 or to obtain only imitations of wood holes 17 or to obtain other structures.

Fig. 6 also shows that the obtained groove 13 may have a structure with a strong rounded portion 18.

Fig. 7 shows a possibility for obtaining sharper structures. Here, when the synthetic material layer is expanded, in step S5, a molding die 19 may be applied, with respect to which the expanded synthetic material layer is raised. This technique can be used to form sharper chamfers 16. In the example represented, the forming die 19 is a substantially flat stamping element. However, it may also be used with one or more embossing cylinders or forming wheels.

Fig. 8 shows another possibility to obtain a sharper structure, such as a sharp chamfer 16. The aforementioned one or more prints 6 for determining the structure are carried out here by so-called degradation, wherein the intensity or the amount of the preparation used for the print 6 is varied depending on the depth that the individual wishes to obtain at that place. It will be apparent that this printing technique may or may not be used in combination with the technique depicted in fig. 7.

The use of such degradation also has advantages in all aspects where the relief is determined at least in part by preferred digital printing.

It is clear that the method of fig. 1 to 6 and the variants of fig. 7 and 8 constitute examples of said first and third aspects and the last-mentioned specific fifth independent aspect.

Figure 9 shows a preferred embodiment of the invention having the features of the first aspect. Here, the third possibility mentioned in the introduction applies for this purpose. Here, the structure is formed on the transfer element 20, in this case on the impression cylinder, by printing 6. The structured embossing cylinder serves to form a relief in the surface of the coated panel 1. The formation of the print 6 on the transfer element 20 is performed in sequence and simultaneously with the formation of the recesses 13 or reliefs in the synthetic material layer 7 of the coated panel 1. In order to form the structure on the transfer element 20, preferably a digital technique (for example a printing technique implemented by means of an inkjet printer 10) is applied, in which, for example, a lacquer or wax is deposited in a pattern on an impression cylinder. Furthermore, fig. 9 shows a configuration in which the printing cylinder can be continuously renewed, since the used structural part of the printing cylinder is removed, for example by the scraping device 21, and replaced by a newly provided structural part. It is clear that the example in fig. 9 also shows the features of two particular independent aspects mentioned in the introduction, namely the second independent aspect and the fifth independent aspect. Also, it is clear that in this embodiment, degradation as described by means of fig. 8 can also be applied.

Fig. 10 shows another example of a method in which a mask 22 is provided on the synthetic material layer 7 and subsequently a subsequent material deposition process is carried out on the synthetic material layer 7. The material deposition process here involves coating the surface of the sheet 1 with a liquid synthetic material 23. Here, the mask 22 is selected such that the synthetic material 23 adheres only to those places where no mask 22 is provided.

Fig. 11 shows the result of this method after the mask 22 and the non-adhering parts of the synthetic material 23 have been removed. On the surface of the panel 1, a relief of the grooves 13 and the projections 14 is obtained. It is clear that this pattern is defined by said mask 22.

Furthermore, it is clear that also when applying a printed mask, it is advantageous to apply a so-called degradation, such as the degradation described by means of fig. 8.

Fig. 12 shows a variant of the method shown in fig. 9, wherein the method comprises at least a step of providing a synthetic material layer 7 on the substrate 2 and a step of providing a relief in the synthetic material by means of a structured mechanical imprinting element 20. Here, the structure of the stamp element 20 is formed in sequence and simultaneously with the step of providing the relief in the synthetic material. In this example, the embossing element 20 relates to a pressure roller. The difference between the embodiment of fig. 12 and the embodiment of fig. 9 is that the synthetic material is now provided with a relief before the structured synthetic material layer 7 is provided on the panel 1. That is, the synthetic material is provided on the already structured part of the stamp element 20 and the synthetic material layer 7 thus formed is at least partially transferred onto the sheet 1.

Fig. 13 shows a further variant of the method, in which, for the embossing element 20, an embossing belt or an embossing web is used instead of a pressure roller, which can be transported on a roller 24 in the direction of the sheet 1. The embossing element 20 is of the type that can be provided on a supply roller 25. This may involve, for example, a foil (e.g. a synthetic foil), a paper sheet or a metal sheet (e.g. an aluminium foil). The dashed line 26 indicates that an endless belt can also be used, wherein then preferably also a scraping device 21 is provided to remove already applied structural parts. In the case of using this endless belt, for example, a metal belt may be used.

Of course, the arrangement of fig. 13 can also be applied when the synthetic material is provided on the board before the relief is realized in the synthetic material layer 7, as is the case with the embodiment of fig. 9. Fig. 13 also shows that the layer of synthetic material can be forced dried by any drying station 27. As the drying stage 27, for example, a hot-air furnace, an ultraviolet heating element or an infrared heating element can be applied.

It should be noted that the imprinting member 20 configuration of fig. 13 on the other side 28 may be structured and achieve similar results. This embodiment is not shown here, but this has the following advantages: the risk of transferring the print 6 partly also to the sheet 1 is minimized.

The arrangement shown in fig. 13 corresponds to the arrangement shown in document WO 2007/059667, but with the difference that a sequentially and simultaneously structured embossing element 20 or embossing web is used instead of a pre-structured material web.

Fig. 14 shows another embodiment in which the risk is minimized. The method shown in fig. 12 is basically used here, but with the difference that a foil 29 is applied between the stamp elements 20, which are structured sequentially and simultaneously. The foil 29 is deformed by the structured stamp element 20, as a result of which the structure of the recesses 13 and the projections 14 is obtained in the underlying synthetic material 7.

It should also be noted that the embodiment of fig. 13 and 14 has the following advantages: the net-shaped stamp element 20, respectively the foil 29, is in contact with the synthetic material of the synthetic material layer 7. It is particularly advantageous when the synthetic material layer 7 comprises wear resistant particles, such as aluminium oxide. In this way, other parts of the arrangement, for example, the press roll 24, can be protected from rapid wear.

Fig. 15 shows a further embodiment similar to the example of fig. 12, wherein, however, the printing 6 for determining the structure or at least parts of the structure is transferred onto the synthetic material layer 7. The technique of fig. 15 may be used to form the mask 22, which may be used, for example, for the technique described in the introduction to the fourth aspect.

Figure 16 shows another example of a method having features of the fourth aspect of the invention. Here, the mask 22, which has initially been provided on the synthetic material layer 7, is imprinted into the synthetic material layer 7 by an imprinting process carried out before the material removal process and/or the material deposition process is applied. In this case, this involves a material removal process, i.e., a painting process S6. A drying process may be applied on the synthetic material layer 7 before the material removal process, so that the actual synthetic material layer 7 is sufficiently resistant to this process S6. Such drying process is not illustrated here, but can be understood to be similar to the drying deck 27 of fig. 13.

Fig. 17 illustrates another example of a method having the features of the fourth aspect. Here, the mask is of this type: the masking portion is for the synthetic material of the synthetic material layer 7 which is situated below the masking portion and is subjected to the material removal treatment of step S6 (in this example, a suction treatment) to a greater extent, which is achieved in this example in the masking portion 30 which contains a material which is impermeable to water or at least provides protection against ultraviolet radiation of the drying deck 27, so that the portion 31 of the synthetic material layer 7 situated below it is cured to a lesser extent or not cured at all. Those portions 31 of the synthetic material layer 7 are subsequently removed in step S6, in which case said portions 31 are removed together with the mask 22 by means of the suction process shown here. It is also possible that the mask 22 is removed in a separate step, preferably before the removal of the non-cured or less cured portions 31 of the synthetic material layer 7.

It is clear that the mask 22 in the embodiment of fig. 17 can be realized by means of a possible digital printing 6, wherein then also embodiments of the first and possibly fifth aspect of the invention are obtained.

Fig. 18 shows an example of using a mask 22, which is made as one such existing entity. In this case the mask comprises a substantially translucent or transparent foil 29, which is provided with masking portions 30 by means of the printing 6. In this example, as is the case in fig. 17, this relates to the masking portion 30 provided for the portion 31 of the synthetic material which is located below the masking portion 30 and is subjected to the material removal process of step S6 (in this example, the suction process) to a greater extent. In a step preceding the material removal treatment, the foil 29 is provided between the radiation source (in this example, the drying station 27) and the synthetic material layer 7, at which position the masking portion 30 forms a selective shield (for example for shielding the ultraviolet radiation emitted by the drying station). Fig. 18 also shows an example of a method of removing the mask 22 from the synthetic material layer 7 in a separate step. In this case, the method is carried out by moving the foil 29 away from the synthetic material layer 7 before the not completely or less completely cured part 31 is subjected to the material removal process of step S6.

It is clear that the masking portions 30 may be provided on either side of the foil 29, or may even be provided on both sides of the foil. The illustrated embodiment has the following advantages: the masking portions 30 can be removed more simply from the synthetic material layer 7. On that side of the foil 29 which is in contact with the synthetic material layer 7, a release layer, for example comprising silicone and/or polytetrafluoroethylene, may be provided.

It is clear that the embodiment of fig. 17 and 18 also forms an example of a method of forming a mask in sequence and simultaneously with the step of providing the relief in the synthetic material. Here, then, in fact, another masking portion 31 other than the masking portion simultaneously formed by the inkjet printer 10 is applied when the relief is provided.

According to a variant not shown, a plurality of masks 22 may be provided in an adjacent and upper-lower manner. In the example of fig. 16, 17 or 18, a further mask 22 can be applied before or after an earlier mask 22 is printed onto the synthetic material layer 7 by means of the imprint process or after the mask 22 has been removed. By careful selection of the individual masks 22, the recesses 13 and/or the projections 14 can be realized with inclined walls and or with different depths.

It is clear that the results of the method according to the invention described in connection with fig. 6, 7 and 9 to 18 can be further finished with one or more finishing layers, such as lacquer layers or the like.

It should be noted that the thicknesses of the material layers and the substrates shown in fig. 2 to 7 and 9 to 18 are only schematically shown without any limitation. It is clear, however, that the thickness of the top layer can be limited to a few tenths of a millimeter, but that the thickness of the substrate may vary between 5 and 15 millimeters or more.

It is important to note that according to all aspects of the present invention, a relatively rigid sheet material can be manufactured without a crimpable coating. The rigid plate has the following advantages: they can easily be provided with connecting means, such as screws, dowels or mechanical connecting means, which enable two such panels, such as floor panels, to be coupled to each other by, for example, milling the sides of the connecting means into the base plate. Such connecting devices and milling techniques are known from WO 97/47834 or DE 202008008597U 1. Due to their rigidity and the presence of the connecting means, the manufactured coated panels are simple to install and do not need to be glued to the substrate.

The invention is in no way limited to the embodiments described above; instead, the method and the sheet can be implemented according to various modifications without departing from the scope of the invention.

Claims (8)

1. Method for manufacturing a coated panel of the type comprising at least a substrate and a top layer with a motif, said top layer being provided on said substrate, wherein the method for realizing the top layer comprises at least two steps, namely a first step of providing a synthetic material layer on said substrate, and a second subsequent step of providing a relief on the surface of said synthetic material layer, wherein said relief comprises a pattern of recesses and/or projections, wherein the relief is at least partly obtained by locally increasing and/or decreasing the volume of said top layer and/or substrate, wherein said pattern is at least partly determined by printing an expansible, expansion-promoting or anti-swelling agent, wherein said printing is performed before said first step, such that said expansible, expansion-promoting or anti-swelling agent can be used underneath said synthetic material layer, wherein the printing is performed by an inkjet printer.

2. The method according to claim 1, wherein the synthetic material layer is a PVC layer and the antiswelling agent is benzotriazole and/or tolyltriazole.

3. Method according to claim 1, wherein a forming die is applied when the synthetic material layer expands, the synthetic material layer increasing in volume relative to the forming die.

4. Method for manufacturing a coated panel of the type comprising at least a substrate and a top layer with a motif, which top layer is provided on said substrate, wherein the method for manufacturing the top layer comprises at least two steps, namely a first step of providing a synthetic material layer on said substrate, and a second subsequent step of providing a relief on the surface of said synthetic material layer, wherein the relief comprises a pattern of recesses and/or projections, which relief is obtained by providing a mask on the synthetic material layer and subsequently performing a material removal or material deposition process on the synthetic material layer, wherein the mask at least partially determines the pattern, wherein the mask is realized directly on the synthetic material layer by inkjet printing.

5. Method according to claim 4, wherein the mask comprises masking portions, which are realized by printing, wherein the synthetic material layer is selectively cured by the mask provided thereon, and wherein uncured or less cured portions of the synthetic material layer are removed by a material removal process carried out on the synthetic material layer, wherein the obtained pattern of grooves and/or protrusions is at least partly determined by the mask.

6. A method according to claim 4 or 5, wherein the mask is implemented as a separate entity.

7. Method according to claim 4 or 5, wherein the mask comprises masking portions, wherein the masking portions are of a type that causes the synthetic material located underneath the masking portions to be subjected to the material removal treatment to a greater extent.

8. -floor panel obtained by a method according to any of the preceding claims.

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