Method for manufacturing a panel

Abstract

Method for manufacturing a panel, wherein this panel is of the type comprising at least a substrate and a top layer provided on this substrate, wherein said top layer comprises at least one film of synthetic material, characterized in that the method comprises at least the step of providing said film on the substrate by means of a high-temperature pressing treatment.

Description

[0001] This invention relates to panels and methods for manufacturing panels.

[0002] More particularly, the invention relates to panels of the type which is at least composed of a substrate and comprises a top layer provided on this substrate, wherein said top layer comprises a printed motif and a transparent or translucent synthetic material layer, which is provided above said printed motif. Herein, this may relate, for example, to furniture panels, ceiling panels, floor panels or the like, which substantially consist of an MDF or HDF (Medium or High Density Fiberboard) basic panel or substrate and a top layer provided thereon. According to a first possibility, it relates to panels obtained by means of a method wherein one or more material layers are provided on the substrate, wherein at least one of these material layers is provided by means of a print which is performed directly on the substrate, wherein this print then forms at least a portion of said printed motif. According to a second possibility, it relates to panels obtained by means of a method wherein one or more material layers are provided on the substrate, wherein at least one of these material layers comprises a printed material sheet, wherein the print of the material sheet then forms at least a portion of said printed motif.

[0003] The panels, manufactured according to said first possibility therefor, are known as such, for example, from US 1,971,067 or DE 195 32 819 A1. From said documents, it is also known that said material layers can comprise one or more primer layers, wherein these primer layers extend substantially underneath said print, and / or can comprise one or more finishing layers, which extend substantially above said print. Such finishing layers can comprise, for example, transparent or translucent synthetic material layers, which form a protective layer above the printed decor and, for example, can comprise wear-resistant particles, such as aluminum oxide. It is not excluded that this protective layer comprises a material sheet, such as a paper sheet.

[0004] The state of the art in connection with panels which are provided with a print performed directly on the substrate further becomes clear also from WO 01 / 48333, WO 02 / 00449, WO 2004 / 042168, EP 1 454 763, DE 197 25 829 C1 and DE 10 2004 009 160 A1.

[0005] It is known, amongst others, from WO 01 / 48333, that for realizing said material layers either lacquers or synthetic resins can be applied. In the case of synthetic resins, those are applied via a carrier sheet, which beforehand is provided with such synthetic resin and, by means of a heated press, is provided on the substrate. In the case of lacquers, for example, UV-hardening lacquers can be applied. Respectively, also wear-resistant particles are applied for obtaining a sufficient wear resistance on the surface of the panel. Such wear-resistant particles, however, lead to a reduced transparency of the material layer concerned.

[0006] It is known, amongst others, from DE 197 25 829 C1 or EP 1 454 763, that one or more synthetic resins, applied in liquid condition, can be used for realizing said material layers. After these resin layers have dried, they are hardened in a heated press. By means of such method, paper-free top layers can be realized. According to the state of the art, an adherence of synthetic resins is only possible on water-based inks. However, the water-based inks are less resistant against UV radiation, for example, as a consequence of sunlight, than UV-based inks.

[0007] Panels manufactured according to said second possibility therefor are known, for example, from WO 97 / 47834 and WO 01 / 96689. Such panels typically comprise a top layer provided above the substrate and being on the basis of thermo-hardening resin, wherein this top layer is composed, by means of a press treatment, of paper sheets provided with resin. One of these paper sheets usually is provided with a printed motif, whereas another paper sheet is transparent and serves as a protective layer for this printed motif. During said press treatment, also a relief can be realized in the surface of said transparent or translucent layer.

[0008] WO 2010 / 084466, which is a document falling under Art. 54(3) and is not relevant to the question of inventive step, discloses floor panels on the basis of MDF or HDF, where upon a DPL top layer is provided by means of a press treatment at increased temperature. WO 2010 / 088769, which is a document falling under Art. 54(3) is not relevant to the question of inventive step, discloses a flooring panel with an MDF or HDF substrate to which e.g. a vinyl foil is joined.

[0009] GB 2 376 916 discloses a laminate substrate made by heat sealing a substrate and a synthetic thermoplastic film, using an adhesive.

[0010] WO 2009 / 141743 discloses heat pressing of a removable film using a structured press element.

[0011] US 5 466 320 discloses floor tiles made of PVC. They are made by laminating, in a nip a preheated PVC film onto an extruded substrate comprising PVC.

[0012] The present disclosure, in first instance aims at providing alternative panels and methods, which, according to various preferred embodiments thereof, can be realized more smoothly and / or economically than the methods of the state of the art. The panels of the disclosure, according to different embodiments thereof, also show mechanical or optical features which mean a progress in respect to the panels known from the state of the art. For example, panels can be obtained which lead to a more acceptable sound when they are used as floor panels, and / or to a more agreeable, warmer feeling.

[0013] The invention is described in claim 1, and preferred embodiments are detailed in the dependent claims.

[0014] The present disclosure, according to a first particular embodiment - not pertaining to the claimed invention -, relates to a panel of the type which comprises at least a substrate and a top layer provided on this substrate, wherein said top layer comprises a motif printed directly on the substrate and a transparent or translucent synthetic material layer, which is provided above said printed motif, with the characteristic that said transparent or translucent synthetic material layer comprises vinyl and that a primer is provided between the printed motif and the vinyl-containing synthetic material layer. Preferably, said translucent synthetic material layer substantially consists of vinyl and / or plasticizer. In that vinyl is applied on the surface, an agreeable feeling is created on the surface of the panels. Said primer allows obtaining in an economic manner an adherence of the vinyl-containing synthetic material layer on an underlying layer, for example, on the inks of the printed motif. The inventors have found that such adherence can be obtained on UV-bases inks as well as on water-based inks. Preferably, there are no further substances and / or layers between the inks of the printed motif and the vinyl-containing synthetic material layer.

[0015] Preferably, the vinyl-containing synthetic material layer has a thickness of at least 0.2 millimeters or more. The inventors have found that such thickness of the synthetic material layer allows already obtaining an acceptable wear resistance, even when the panel of the invention should be applied as a floor panel. Moreover, such layer has a good transparency. With such thickness of the vinyl-containing synthetic material layer, the use of wear-resistant particles, such as aluminum oxide particles, which usually are applied in floor panels, can be omitted in this layer. Such wear-resistant particles have a negative influence on the transparency of the synthetic material layer, and restricting the amount of such particles leads to a better rendition of said printed motif. Preferably, in the case that wear-resistant particles are applied, less than 10 or still better less than 5 grams per square meter of such particles are applied. Of course, the disclosure as such does not exclude that a larger amount of such particles should be applied in the vinyl-containing synthetic material layer.

[0016] Preferably, the thickness of said vinyl-containing synthetic material layer is less than 1 millimeter. Such thickness leads to a very wear-resistant surface layer, which in most cases will be sufficient and still is sufficiently transparent.

[0017] A very interesting value for the thickness of said vinyl-containing top layer, which offers an optimum between cost price and wear resistance, is in the range of 0.25 to 0.5 millimeters. With such thickness, additional wear-resistant particles are not necessary.

[0018] It is noted that according to the disclosure of said first particular embodiment, which does not pertain to the invention, still one or more further layers can be provided above said vinyl-containing synthetic material layer. The common thickness of these further layers preferably is smaller, and still better is at least 5 times smaller than the thickness of the vinyl-containing synthetic material layer. Said further layers may comprise, for example, UV-hardened layers, which can lead, for example, to an increased resistance against the development of black stripes rubbed off by shoe soles. It is not excluded that said one or more further layers comprise wear-resistant particles, which result in an increased scratch resistance. Herein, this may relate, for example, to aluminum oxide or silicon oxide particles having an average diameter which is smaller than 60 micrometers and still better smaller than 10 micrometers. It is also not excluded that these further layers are free from such wear-resistant particles or at least comprise less than 10 grams or less than 5 grams per square meter of such particles.

[0019] Preferably, a primer is applied which comprises a polymer with aliphatic character or substantially is based on such polymer. The inventors have found that polymers with aliphatic character, compared to polymers with aromatic character, are much less inclined to yellowing and thus can guarantee a better transparency of said vinyl-containing synthetic material layer. Of course, it is not excluded that within the idea of the disclosure still a primer on the basis of aromatic polymers might be used. In such case, preferably also UV blockers and / or whiteners are applied in the primer and / or in the vinyl-containing synthetic material layer situated there above. As a whitener, for example, a substance can be applied which comprises a derivate of a distyryl biphenyl compound.

[0020] Preferably, said primer comprises polyurethane and / or polyisocyanurate, or the primer is based on one or both of these polymers. As aforementioned, this preferably relates to the aliphatic variant of these agents. The inventor has found that polyurethane or polyisocyanurate realizes in an economic manner a good adherence between a vinyl-containing synthetic material layer and the inks of a printed motif. This may relate, for example, to UV-based inks or water-based inks.

[0021] Preferably, said transparent or translucent synthetic material layer is free from material sheets, such as paper sheets or synthetic material sheets or films. Such sheets have a negative influence on the transparency of the respective layer; moreover, they involve an extra cost.

[0022] As aforementioned, said transparent or translucent synthetic material layer preferably is free from additives which increase the wear resistance of the panel, or at least it comprises less than 10 grams per square meter of such additives.

[0023] Said vinyl, which at least partially forms the transparent or translucent synthetic material layer, preferably relates substantially to polyvinyl dichloride (PVdC). Generally, PVdC is more expensive than PVC (Polyvinyl chloride), but has lower water permeability. Water resistance is a desired feature for many decorative surfaces, such as for floor panels or furniture panels. The disclosure does not exclude that use could be made of vinyl which substantially relates to polyvinyl chloride.

[0024] According to a variant, a more environmentally-friendly panel can be obtained when said vinyl at least partially and preferably substantially or exclusively relates to a chlorine-free vinyl compound, preferably chosen from the list of polyvinyl butyrate, polyvinyl alcohol and vinyl acetate, such as EVA (Ethylene vinyl acetate).

[0025] Preferably, said vinyl-containing synthetic material layer, and still better the entire top layer, is free from plasticizers or contains maximum 35 parts by weight of plasticizer per 100 parts by weight of vinyl compound, or still better less than 20 parts by weight. Restricting the plasticizer contents results in a sturdier surface having a better impact resistance. Moreover, omitting plasticizers to a large extent is interesting when manufacturing such panels, as the risk of the development of harmful materials, for example, vapors, is restricted in this manner. When plasticizer is applied, for example, phthalate-based plasticizers can be chosen, such as DINP (di-isononyl phthalate). Preferably, in such case, however, it is opted for plasticizers on the basis of isosorbide. These last-mentioned plasticizers are more environmentally-friendly.

[0026] According to a deviating variant of said first particular embodiment, which per se does not pertain to the invention, said synthetic material layer comprises polyurethane instead of vinyl, wherein this polyurethane preferably is aliphatic, and wherein this preferably relates to so-called polyester-based thermoplastic polyurethane. The inventors have found that the use of such synthetic material layer results in obtaining a good scratch resistance on the surface of the panels. Moreover, polyurethane shows a better resistance against staining by shoe soles than vinyl. Thus, an additional UV-based surface layer for restricting or counteracting this phenomenon is redundant in the case of a polyurethane-containing surface layer. Preferably, the polyurethane synthetic material layer thus forms a transparent or translucent layer, which is present on the actual surface of the panel. Preferably, the thermoplastic polyurethane layer or film has a thickness situated between 0.1 and 0.3 mm, or a plurality of such layers or films have a common thickness situated between 0.1 and 0.3 mm. Such thickness suffices for obtaining a wear resistance which is acceptable for floor panels. Of course, thicker layers are not excluded, as they can lead to a still higher wear resistance. The inventors have found that a thickness of 0.15 mm allows obtaining a Taber IP value (EN 13329) of 3000 or more. This value can even be obtained when the synthetic material layer is free from additional wear-resistant particles. When an aromatic polyurethane is applied, preferably also use is made of a UV blocker or whitener, such as a substance which comprises a derivate of a distyryl biphenyl compound. The inventors have also found that for performing press treatments on a polyurethane-containing synthetic material layer, for example, with a metal press platen, no additional measures have to be taken for detaching the press platen and the synthetic material layer.

[0027] It is noted that the above deviating variant can be a panel obtainable via a method in accordance with the claimed invention, wherein said panel is of the type which comprises at least a substrate and a top layer provided on this substrate, wherein said top layer comprises a printed motif and a transparent or translucent synthetic material layer, which is provided above said printed motif, with the characteristic that said transparent or translucent synthetic material layer comprises polyurethane. It is clear that herein the printed motif is provided on a carrier material, which is a synthetic material film, preferably a polyurethane film. Further, it is clear that not necessarily use is made of a primer.

[0028] As an alternative - in accordance with the claimed invention, said vinyl-containing layer or a portion thereof also is applied as one or more vinyl-containing synthetic material films. According to the invention, in the also above-mentioned deviating variant, the polyurethane or a portion thereof is provided on the substrate as one or more films.

[0029] The panel obtainable via a method in accordance with the claimed invention comprises a relief on the surface thereof, wherein this relief extends in the vinyl-containing synthetic material layer; however, preferably the recesses of said relief are only so deep that they do not penetrate in said printed pattern. For providing such relief, use is made of a technique wherein the structure of a structured press element is copied into the surface of the vinyl-containing synthetic material layer by means of a press treatment. Preferably, said synthetic material layer is heated prior to and / or during the press treatment. By the heating of the synthetic material layer, the synthetic material layer preferably is made softer, by which the press treatment can be realized at a lower pressure. In the case of preceding heating, preferably use is made of a radiation source, such as an infrared radiator. In the case that heating is performed during the press treatment, then heating is performed preferably by means of thermal oil with which the press device and the press element are warmed up. Preferably, said synthetic material layer is forcedly cooled during pressing and / or thereafter. By cooling, the structure on the surface of the synthetic material layer will be conserved better. Preferably, during the press treatment a temperature of 130°C or more is achieved. For said cooling, either use can be made of the same press treatment, or use can be made of a separate treatment and press device, which then preferably is not heated or even is cooled. It is also possible that the above-mentioned structured press element is applied only during this cooling, and / or that in such case during the first press treatment solely an adherence between the different layers of the panel is obtained. Said cooling implies that the consolidated panel is still warm from the first press treatment and / or is re-heated before it is subjected to the second press treatment.

[0030] Preferably, an opening and closing discontinuous press or a so-called short-cycle press is applied, wherein per cycle each time one package of a substrate, printed motif and synthetic material layer is pressed. It is also possible to work with so-called multiple-opening presses, wherein then a plurality of packages can be pressed per cycle.

[0031] According to a first special preferred embodiment, the method of the invention is applied for manufacturing panels of the type which comprises at least a substrate and a top layer provided on said substrate, wherein said top layer comprises a vinyl-based synthetic material layer, characterized in that said substrate preferably is a wood-containing or wood-based substrate and that a primer is provided between the substrate and said vinyl-based synthetic material layer. Preferably, no further substances or layers are situated between the substrate and said primer and / or between said primer and said vinyl-based synthetic material layer.

[0032] Preferably, as a primer a polyurethane-containing substance is applied, such as a polyurethane-based dispersion glue. Preferably, this primer provides for the binding between said synthetic material layer and the substrate, and still better no further binding agents are present for this purpose.

[0033] In accordance with the invention, said vinyl-based synthetic material layer relates to a vinyl film, for example, a PVC film. Herein, this relates to a decor film, which shows a printed pattern, and to a transparent film. Preferably, said vinyl-based synthetic material layer relates at least to a decor film, which is printed by means of solvent inks. With solvent inks, a very high printing quality can be achieved. According to a variant in accordance with the claimed invention, use is made of a polyurethane-containing synthetic material layer, being a thermoplastic polyurethane film.

[0034] According to a particular embodiment - in accordance with the claimed invention -, said vinyl-based synthetic material layer comprises a transparent or translucent vinyl-base film as a decor film on the basis of vinyl, wherein said transparent or translucent vinyl-based film is provided above said decor film.

[0035] According to the invention, the surface of the panel, more particularly the vinyl-based synthetic material layer is provided with a relief.

[0036] As afore stated, the invention is as defined in claim 1, and relates to a method for manufacturing a panel, wherein this panel is of the type which comprises at least a substrate and a top layer provided on this substrate, wherein said top layer comprises at least a synthetic material film, with the characteristic that the method comprises at least the step of providing said film on the substrate by means of a press treatment at increased temperature.

[0037] The method of the invention further can also comprise at least the step of providing a primer on the substrate, preferably a polyurethane dispersion glue.

[0038] As synthetic material film, preferably use is made of a PVC film or a thermoplastic polyurethane film. This film either can be printed and form the possible printed motif of the panel, or can be made transparent or translucent and in this manner form a protective layer above such possible motif. In the case of polyurethane, preferably the aliphatic variant is used, or an aromatic variant, which then preferably contains UV blockers and / or whitener.

[0039] Preferably, said substrate relates to a wood-containing or wood-based substrate, such as MDF or HDF or wood particle board. According to a variant, said substrate comprises a foamed synthetic material, such as foamed polyethylene or foamed polyvinyl chloride.

[0040] Generally, said substrate preferably relates to a porous substrate, such as it is the case with the aforementioned substrates. By means of such substrate, a good resistance against delamination, or, in other words, against a separation of the top layer, can be achieved. In principle, it suffices when the surfaces of said substrate, which is provided with the top layer, is porous. However, it is not excluded that the entire substrate is made porous.

[0041] In accordance with the invention, said top layer comprises at least two synthetic material films, wherein said two films comprise a decor film and a transparent film. Possibly, herein this may relate to airtight films. In that case, preferably measures are taken against the occurrence of air inclusions between both synthetic material films. For example, one or both of the synthetic material films can be made perforated, such that possibly accumulated air can escape along these perforations.

[0042] The method of the invention can comprise a step which is performed prior to the step of the press treatment, wherein in this preceding step, said two synthetic material films are laminated to a composed film. In this manner, the logistics of the method are simplified. In the case of airtight films, in this manner any air inclusions are avoided already prior to the press treatment. Preferably, laminating is performed by means of a calendaring device or another device, in which rollers are applied. By means of rollers, the air can be expelled gradually from in between said synthetic material films.

[0043] Preferably, said press treatment is performed at a temperature situated between 80°C and 150°C, or still better between 110°C and 140°C. Such temperature is sufficient for achieving an adherence of the synthetic material films over the primer with the substrate. Preferably, an opening and closing discontinuous press or a so-called short-cycle press is applied, wherein per cycle respectively one package of a substrate and one or more synthetic material films are pressed. It is also possible to work with so-called multiple-opening presses, wherein then a plurality of packages per cycle can be pressed.

[0044] Preferably, said press treatment is performed with a pressing time which is shorter than one minute. The inventors have found that such pressing time is sufficient for achieving a good adherence. According to a preferred embodiment - not in accordance with the claimed invention -, it is started from at least one flat, unstructured synthetic material film, preferably a transparent or translucent synthetic material film, which in said press treatment is adhered on the substrate and is provided with a structure as well. For realizing said structure, during the press treatment preferably use is made of a structured press element, for example, a structured press platen or press plate. Preferably, said structure is performed in accordance with a printed motif, for example, the motif of the possible decor film. Preferably, the structure is obtained in a press treatment performed in an opening and closing press. Preferably, said press element is provided with a coating, which promotes detaching the press element from the panel.

[0045] For the quality of the obtained structure, it can be desirable that said package is cooled down under pressure. To this aim, either use can be made of the same press treatment in which the top layer is adhered to the substrate, or use can be made of a separate press device, which then preferably is not heated or possibly even is cooled. It is also possible that the above-mentioned structured press element is applied only during this cooling down. In accordance with the invention, during the first press treatment only an adherence between the different layers of said package is obtained. Said cooling down implies that the consolidated package still is warm from the first press treatment and / or is heated up again before being subjected to the second press treatment.

[0046] The claimed invention is defined in claim 1 and relates to a method for manufacturing a panel, wherein this panel is of the type which comprises at least a substrate and a top layer provided on this substrate, wherein said top layer comprises thermoplastic synthetic material, with the characteristic that the method comprises at least a first step, wherein said thermoplastic synthetic material is subjected to a first temperature and a first pressure, and comprises at least a second step, wherein in this thermoplastic synthetic material a structure is formed and the thermoplastic synthetic material is subjected to a second temperature and a second pressure, wherein said first temperature is higher than said second temperature and said second pressure preferably is higher than said first pressure.

[0047] The inventors have found that forming a structure at a lower temperature, after the thermoplastic synthetic material has been subjected to a heat treatment on a lower pressure, leads to a better rendition and keeping of the provided structure.

[0048] For the motif, use is made of a printed synthetic material film, such as a printed vinyl-based film, or a printed polypropylene film, or a printed polyethylene film, or a printed polyurethane film. The print is situated on the upper side of this film. Preferably, the connection between the printed synthetic material film and the substrate is obtained at least by the intermediary of an adhesive layer, preferably by the intermediary of a polyurethane dispersion glue.

[0049] Said thermoplastic synthetic material, when performing said second step, forms the surface of a consolidated package, which comprises at least the substrate, the motif and the thermoplastic synthetic material. According to an alternative, said thermoplastic synthetic material in this stage of the method is finished further with one or more layers provided there above, which comprise, for example, UV-hardening or hardened layers. In any case, the thermoplastic synthetic material relates to a layer of transparent or translucent thermoplastic synthetic material, which is applied above the motif as a synthetic material film. As a material for the thermoplastic synthetic material, it is opted for vinyl-based synthetic material, such as PVC, or for polypropylene, polyurethane or polyethylene.

[0050] According to the claimed invention, for the motif as well as for the transparent or translucent layer use is made of a film, and these are laminated onto each other at least prior to said second step, to form a consolidated package, which comprises at least the laminated films and the substrate. Laminating can be performed by means of a calendar device.

[0051] In connection with said first step a consolidated package is formed, which comprises at least said motif, said thermoplastic synthetic material and said substrate. Such consolidated package at least is available prior to said second step. Possibly, this consolidated package further can also comprise a thermoplastic back layer on the lower side of the motif or the printed synthetic material film. According to the claimed invention, a calendar device or a continuous press device is applied for bringing together the two or more layers of the consolidated package.

[0052] In the case that the top layer includes a back layer, which is not necessarily the case, preferably a back layer is used which consists of PVC or another thermoplastic synthetic material, preferably recycled PVC, and preferably is filled with chalk. Such back layer preferably forms at least 30% and still better at least 45% of the thickness of the top layer.

[0053] The aforementioned first temperature and first pressure to which said thermoplastic synthetic material is subjected, can, as aforementioned, be created by forming the consolidated package of at least the substrate, the motif and the thermoplastic synthetic material, by means of a calendar device or a continuous press device. According to another possibility, those are generated by means of a heating device, such as by means of a radiation source, preferably an infrared lamp. In this last case, it is clear that the first pressure can be equal to atmospheric pressure. The first temperature is higher than room temperature (23°C) and, for example, is at least 50 percent and still better more than 80 percent or more of the glass transition temperature (Tg), expressed in degrees Celsius, of the respective thermoplastic synthetic material. Of course, the first temperature may also be higher than the glass transition temperature, preferably, however, more than 150 percent thereof. In this suggested range of the first temperature, an ideal suitable softness of the thermoplastic synthetic material is achieved for proceeding to said second step. Preferably, said second step is performed without forcedly cooling the thermoplastic synthetic material in between and / or without applying a period of rest. Preferably, the thermoplastic synthetic material, at the beginning of the second step, has at least 80 percent of the temperature which this synthetic material had at the end of the first step, and in any case, in accordance with the claimed invention, has at least a temperature which is higher than room temperature.

[0054] Said second temperature and second pressure to which said thermoplastic synthetic material is subjected, can be generated by means of a press treatment with a structured press element,. Preferably, an opening and closing discontinuous press device or a so-called short-cycle press is applied, which comprises a structured press plate or press platen. Preferably, in the second step a cooling down under pressure of the thermoplastic top layer is achieved, whereas at the same time, according to the claimed invention, a relief is realized in the surface of the thermoplastic synthetic material and the consolidated package. Preferably, the press device, including the press platen, is kept on a temperature which is lower than the temperature of the thermoplastic synthetic material at the beginning of said second step. Preferably, at the press device, including the press platen, no heat is supplied except the possible heat of the thermoplastic synthetic material itself. Said second temperature preferably is between 20 and 55°C or less than 50 percent of the glass transition temperature of the respective thermoplastic synthetic material. Said second pressure preferably is between 1 and 10 bar. The inventors have found that short pressing times can be handled, for example, pressing times of less than a minute, such as between 5 and 50 seconds or even between 5 and 25 seconds. Preferably, a structure in accordance with the motif is obtained.

[0055] Preferably, in said second step, compared to said first step, a separate device is applied.

[0056] According to a first important example of the invention, prior to the first step a composition is formed, which comprises an MDF substrate, a back layer provided on the upper side of the substrate, and a backing layer or underlying layer provided on the lower side of the substrate. This composition is obtained by gluing the underlying layer and back layer to the substrate by means of a polyurethane-based glue, such as a polyurethane dispersion glue. Subsequently, a printed synthetic material film and a transparent or translucent thermoplastic film, such as a PVC film, is placed on the composition, more particularly on the side thereof which comprises the back layer. This package is consolidated in a first step by means of a heated press device, for example, a continuously working press device. During this press treatment, said first temperature and first pressure are achieved. Herein, consolidation takes place in that the initial composition and the synthetic material films melt together at the locations where they are adjacent to each other. In a second step, the still warm consolidated package is supplied to an unheated short-cycle press, which comprises a structured press element. After a pressing time of 15 seconds, a structured panel is obtained. As the short-cycle press is unheated, the second temperature can be kept lower than the first temperature in a simple manner. However, preferably the second pressure is higher than the first pressure.

[0057] According to a second important example of the invention, prior to the first step a composition is formed comprising an MDF substrate and a backing layer or underlying layer provided on the lower side of the substrate. This composition is obtained by providing the underlying layer as a liquid or paste-like substance on the substance and hardening or drying it there. The upper side of the substrate is spread with glue, such as with polyurethane-based glue, for example, with polyurethane dispersion glue. Subsequently, a printed synthetic material film and a transparent or translucent thermoplastic film, such as a PVC film, is placed on the composition, more particularly on the side thereof which comprises the glue. In a first step, this package is consolidated by means of a heated press device, for example, a continuously working press device. During this press treatment, said first temperature and first pressure are achieved. Herein, the consolidation takes place in that the initial composition and the printed film are glued to each other and at the same time the synthetic material films mutually melt together at the locations where they are adjacent to each other. In a second step, the still warm consolidated package is supplied to an unheated short-cycle press, which comprises a structured press element. After a pressing time of 15 seconds, a structured panel is obtained. As the short-cycle press is unheated, the second temperature can be kept lower than the first temperature in a simple manner. However, preferably the second pressure is higher than the first pressure.

[0058] According to a third important example of the invention, prior to the first step a composition is formed comprising an MDF substrate and a backing layer or underlying layer provided on the lower side of the substrate. This composition is obtained by providing the underlying layer as a liquid or paste-like substance on the substance and hardening or drying it there. The upper side of the substrate is spread with glue, such as with polyurethane-based glue, for example, with polyurethane dispersion glue. Prior to the first step, also a composed film is formed on the basis of a printed synthetic material film and thermoplastic synthetic material, for example, also in the form of a film. This composition can be performed by laminating both. Subsequently, the composed film is placed on the substrate, more particularly on the side thereof which comprises the glue. This package is consolidated by reaction of the glue. In a first step, the consolidated package is heated by means of an infrared radiation device. During this heating step, said first temperature and first pressure are achieved. In this case, the first pressure is equal to the atmospheric pressure. In a second step, the still warm consolidated package is supplied to an unheated short-cycle press, which comprises a structured press element. After a pressing time of 15 seconds, a structured panel is obtained. As the short-cycle press is unheated, the second temperature can be kept lower than the first temperature in a simple manner. However, in this case preferably the second pressure clearly is higher than the atmospheric pressure.

[0059] It is clear that the panels from the first through the third example can be subjected to still other treatments before the final floor panels are obtained. For example, the panel can also be divided into a plurality of smaller panels having approximately the dimensions of the final floor panels.

[0060] It is noted that by means of the invention a very good correspondence between structure and motif can be obtained. According to the state of the art, which substantially applied continuous press devices and / or multiple-opening presses, up to now such correspondence is unattained. Preferably, said structure is realized exclusively by means of said second step and thus, at the beginning of the second step, the thermoplastic synthetic material is still free from relief or any structure.

[0061] According to the invention, preferably a porous substrate is applied, such as a wood-based substrate. The substrate may relate, for example, to a MDF or HDF (Medium Density Fiberboard or High Density Fiberboard) or a wood particle board. Other possible substrates are substrates which comprise foamed material, such as a substrate which comprises foamed polyethylene or polyvinyl chloride. Preferably, the substrate has a density of less than 800 kilograms per cubic meter and still better of less than 500 kilograms per cubic meter, wherein these lowest densities preferably are achieved by means of said substrates which contain foamed material.

[0062] Preferably, the present invention relates to floor panels or other panels which as such are rigid and thus as such cannot be wound up. Preferably, the final panel has a thickness of more than 5 millimeters, however, preferably less than 15 millimeters. A good value for the thickness is 7 to 10 millimeters. Such panels are very suitable for providing mechanical coupling means thereon, which allow connecting two or more of such panels at their edges to each other. Preferably, herein use is made of mechanical coupling means, such as of the type known from WO 97 / 47834.

[0063] Where calendaring or calendar devices are mentioned, a device is intended where two layers are adhered to each other at least by means of rollers, and preferably by supplying heat.

[0064] It is clear that, when a synthetic material film is mentioned, it is intended that this film essentially consists of synthetic material and thus is free from other materials, such as paper.

[0065] Further, it is also noted that in the methods of the invention one may possibly start from manufacturing larger boards, from which then by subdividing, for example, by means of a sawing treatment, a plurality of panels, such as floor panels, can be obtained. This dividing step can take place anytime, and it is not necessary that all essential steps of the invention already have been performed before such subdividing takes place. Namely, one or more partial steps can be performed on the smaller panels.

[0066] The present invention is in no way limited to the herein above-described embodiments; on the contrary, such methods can be realized according to various variants without leaving the scope of the present invention, as defined by the appended claims.

Claims

1. Method for manufacturing a panel, wherein this panel is of the type which comprises at least a substrate and a top layer provided on this substrate, wherein said top layer comprises at least two synthetic material films, wherein said two films comprise a decor film and a transparent film, wherein said decor film is a printed synthetic material film chosen from the list consisting of a vinyl-based film, a polyethylene based film, a polyurethane based film and a polypropylene film, with the print being situated on the upper side of said film, and wherein said transparent film is a thermoplastic synthetic material film the material of which is chosen from the list consisting of polyvinyl chloride, polyethylene, polyurethane and polypropylene, characterized in that the method comprises at least a first step of providing said films on the substrate by means of a press treatment at a first temperature to form a package of said substrate and said synthetic material films, wherein said thermoplastic synthetic material forms the surface of said consolidated package, wherein said first step uses a calendar device or a continuous press device, wherein said first temperature is an increased temperature higher than room temperature (23°C), and at least a subsequent second step wherein a structure is formed in said thermoplastic synthetic material by means of a press treatment using a press device with a structured press element at a second temperature, said first temperature being higher than said second temperature, wherein the thermoplastic synthetic material, at the beginning of the second step, has a temperature at least higher than room temperature.

2. Method according to claim 1, characterized in that said method further also comprises at least the step of providing a primer, preferably a polyurethane dispersion glue, on the substrate.

3. Method according to claim 1 or 2, characterized in that said substrate relates to a wood-containing or wood-based substrate.

4. Method according to any of the claims 1 to 3, characterized in that said substrate comprises a foamed synthetic material.

5. Method according to any of the preceding claims, characterized in that no heat is supplied to said press device with said structured press element.

6. Method according to any of the preceding claims, characterized in that the method comprises a step which is performed prior to the first step, wherein in this preceding step said two synthetic material films are laminated to a composed film.

7. Method according to any of the claims 1 to 6, characterized in that said press treatment of said first step is performed with said first temperature situated between 80 and 150°C.

8. Method according to any of the claims 1 to 7, characterized in that said press treatment of said first step is performed with a pressing time shorter than one minute.

9. Method according to any of the preceding claims, characterized in that said thermoplastic material forming the surface of said consolidated package is structured exclusively by means of said second step.

10. Method according to any of the preceding claims, characterized in that said decor film is a polyvinyl chloride film.

11. Method according to any of the preceding claims, characterized in that the surface of said substrate which is provided with the top layer is porous.

12. Method according to any of the preceding claims, characterized in that the material of said transparent film is polyvinyl chloride.