BE1027441A1 - Plate material and floor panel based on such plate material - Google Patents

Abstract

Plate material with at least two material layers (17-19), in which a first material layer (17) forms more than half the thickness (T) of the plate material (16) and is mainly composed of glued and pressed by means of a first binder. wood particles (18), wherein the first binder is thermosetting, characterized in that the second material layer (19) is present on the surface of the aforementioned plate material (16) and is mainly composed of particulate particles glued and pressed by means of a second binder (20), wherein the second binder is thermoplastic and / or elastomer.

Description

Plate material and floor panel based on such plate material.

This invention relates to a plate material and a floor panel based on such plate material.

More specifically, the invention relates to sheet materials that can be used for manufacturing imitation floor panels.

Such floor panels are known per se.

From WO 97/47834, for example, laminate floor panels with a substrate based on wood fiber board, such as MDF or HDF (Medium or High Density Fiberboard) are known. Such laminate floor panels comprise a top layer, based on one or more melamine resin impregnated paper sheets, including a printed paper sheet comprising, for example, a printed representation of a wooden floor panel.

The printing is protected by a transparent wear layer which is also based on a paper sheet impregnated with melamine, or a so-called overlay.

It is well known that the prior art laminate floor panels can give rise to undesirable noises, such as ticking noises, when used.

Such noises can be irritating and indicate that it is an imitation of, for example, real wooden parquet, although the appearance of such panels is hardly distinguishable.

The use of melamine resin in the top layer can further give rise to residual tensile stresses in the top layer.

As a result, high demands must be made on the substrate.

For example, it is desirable that a peak in density occurs on the surface of the typical MDF or HDF board that is able to withstand the high tensile stresses in the top layer.

This peak in density can limit the risk of breakage in the top layer in the event of an impact.

It is noted that in the standard production of MDF or HDF such peak density is created near the surface because the mat of glued wood fibers to be pressed is inhomogeneously heated.

The fibers close to the heating elements, namely on both surfaces of the fiber mat to be pressed, harden faster than the fibers located centrally in the fiber mat.

This creates an inhomogeneous compaction.

The present inventors have now come to the conclusion that this peak in the density in the hard MDF or HDF material gives rise to sounds in a frequency range that is experienced as irritating.

It is noted that laminate panels, as mentioned above, are usually manufactured in practice by the so-called DPL (“Direct Pressure Laminate”) process. A stack is herein formed with the substrate and the desired impregnated paper sheets for the formation of the top layer and any counter layer on the underside of the panel. This stack is then consolidated in a heated pressing operation using a Kurz-stroke press and the resin present is cured. Optionally, a structure can be provided on the surface of the panel in that the relevant press is equipped with a structured press element. The presence of the aforementioned peak in density at the surface of the MDF or HDF substrate can lead to problems in pressing, especially when relatively deep structural elements are to be formed, for example structural elements with a depth of 0.2 mm or more, and / or with a depth greater than the thickness of the top layer, as is the case in WO 2006/066776. In the meantime, alternatives to laminate floor panels have entered the market, which, among other things, produce a more acceptable sound. It concerns, for example, floor panels with a thermoplastic top layer and / or a flexible plastic core, as disclosed, for example, in WO 2011/077311 or WO 2011/141849. Also known from WO 03/016655, possibilities are known for damping ticking noises in laminate floor panels to some extent by laminating an extra sound-damping layer at a position under the printed decorative sheet. Such a solution results in a quieter sound, but remains unnatural. In addition, the proposed solution has a reduced impact resistance. The relatively brittle laminate layer can crack when, on impact, it follows the deformation of the underlying, softer, sound-damping layer. The method for manufacturing panels according to WO'655 is laborious, because the sound-insulating layer must be glued separately to the substrate.

From WO 2010/088769 it is known to impregnate paper sheets for the production of laminate floor panels with polyurethane, and from WO 2010/006409 a plate material is known in which wood fibers are bonded by means of a binder based on isocyanate and polyol.

The cost associated with the manufacture of panels according to WO 769 or WO 409 is high and the properties of the board material of WO 409 may be insufficient to achieve a floating laminate floor covering.

EP 1 847 385 B1 proposes, with a view to better water resistance, a plate material having three material layers, in which a central material layer 1s is composed of wood chips or wood fibers glued and pressed by means of a first binder, and wherein on both surfaces of the plate material a second and third material layer is present, which is made up of so-called WPC, ie wood-plastic composite.

The aforementioned WPC comprises fibrous particles glued and pressed by means of a second binder, the second binder being an electrically conductive plastic, such as polyaniline or polypyrrole.

The present invention aims in the first place to offer an alternative plate material, whereby according to various preferred embodiments a solution is offered to one or more of the problems with the plate material from the prior art, or with the floor panels based on such sheet material are manufactured.

To this end, according to its first independent aspect, the invention relates to a plate material with at least two material layers, wherein a first material layer forms more than half the thickness of the plate material and is mainly composed of wood particles glued and pressed by means of a first binder, wherein the first binder is thermosetting, characterized in that the second material layer is present on the surface of the aforementioned plate material and is mainly composed of particulate particles glued and pressed by means of a second binder, wherein the second binder is thermoplastic and / or elastomer, or at least substantially comprises thermoplastic and / or elastomeric binder.

The inventors have found that the use of particulate particles bonded with a thermoplastic and / or elastomeric binder on the surface of a board material further bonded by a thermoset, the tapping sound produced by such board material is very similar to that of real wood.

In addition, the second material layer allows smooth structuring of the associated surface and / or may show some spring back when deformed in use. Such a plate material may further have a strength, as expressed by IB (“Internal Bond” measured according to EN 319: 1993), which is comparable or the same as the plate materials of the prior art. The presence of the aforementioned first material layer is important here. Preferably, the thickness of the aforementioned first material layer is at least three times the thickness of the aforementioned second material layer.

Preferably, the aforementioned plate material consists of the aforementioned two material layers. Preferably, the aforementioned first material layer here forms at least 75% of the thickness of the plate material, and the aforementioned second material layer here forms 25% or less of the thickness of the plate material. According to this embodiment, the first material layer offers sufficient mechanical strength, while the second material layer can be adjusted to produce the desired sound, and / or to be easily structured. The inventors have established that the obtained asymmetrical construction of the plate material does not necessarily give rise to dimensional instability, such as cupping. It is in fact possible to obtain a symmetrical density profile through the thickness of the plate material, despite the asymmetrical material structure. Preferably, the particulate particles of the aforementioned second material layer are or contain wood chips. Wood chips have internal vascular channels and thus allow a more flexible second material layer to be obtained than would be the case if wood fibers were used in the second material layer. It is of course also possible to work with other particulate particles or with a mixture of particulate particles from different materials. For example, it is possible to use ground, preferably hard, plastic and / or rubber as particulate particles, or to make use of ground textile or carpet waste. The particulate particles, in particular wood chips, of the second material layer can be impregnated with a plastic, such as glycerol. This is to improve the performance of the second binder. The particulate particles of the aforementioned second material layer can also be or contain wood fibers. Preferably, the wood particles of the aforementioned first material layer are wood fibers.

Preferably, the aforementioned first binder is selected from the range of melamine formaldehyde, urea formaldehyde, melamine urea formaldehyde, phenol formaldehyde, phenol-urea formaldehyde, MDI (methylene diphenyl diisocyanate), pMDI (polymeric methylene diphenyl diisocyanate binder obtained by reaction of an acrylonitrile and acrylate resin) dextrose, such as, for example, a binder as described in EP 2 457 954.

Preferably, the first material layer has the material structure of a wood fiber board, such as MDF or HDF, namely wherein the wood particles are wood fibers and more preferably with a first binder selected from the range of melamine formaldehyde (MF), urea formaldehyde (UF), melamine urea formaldehyde ( MUF), MDI (“methylene diphenyl diisocyanate”) and pMDI (“polymeric methylene diphenyl diisocyanate”).

Preferably, the particulate particles of the aforementioned second material layer exhibit a particle size of 500 micrometers or more, as expressed by the d50 value measured by laser light diffraction granulometry, preferably in accordance with ISO13320 (2009). Such particulate particles provide a more compactable and resilient second material layer that is well able to absorb and dissipate vibration. Preferably, the particle size as expressed with the above d50 value is less than 3 mm. The most preferred range for the d50 value of the particulate particles is between 1 and 2.4 mm.

Preferably, the aforementioned second binder is thermoplastic and is selected from the range of polyvinyl butyral (PVB), polyvinyl butyrate, polyvinyl chloride (PVC), polyvinyl dichloride (PVdC), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), thermoplastic polyurethane (TPU), thermoplastic aliphatic polyester, such as polylactic acid (PLA), thermoplastic olefin (TPO). Preferably, the second binder is halogen-free, preferably selected from the range of polyvinyl butyral (PVB), polyvinyl butyrate, polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET) and thermoplastic polyurethane (TPU). According to a variant, the aforementioned second binder is elastomer and is selected from the range of synthetic rubber (neoprene), cross-linked or non-cross-linked polyvinyl butyral (PVB), silicone and natural rubber (polyisoprene).

According to a special possibility, the aforementioned second binder is at least partially obtained as a recyclate. For example, the aforementioned polyvinyl butyral (PVB) can be recovered from the recycling of glass, more especially the recycling of safety glass.

Preferably, said second binder contains or consists of polyvinyl butyral, more preferably cross-linked polyvinyl butyral. Preferably, one or more of the series epoxy resin, dialdehydes, phenolic resin and melamine resin are used as crosslinkers.

Polyvinyl butyral (PVB) that can be cross-linked is formed when not all of the hydroxyl groups of the polyvinyl alcohol react with butyraldehyde in the production of the polyvinyl butyral. As a result, the polyvinyl butyral (PVB) still contains hydroxyl groups that can cause a crosslinking by reaction with crosslinkers ("crosslinkers"), whereby an elastomer polyvinyl butyral (PVB) is formed.

Preferably the said second binder contains or consists of polyvinyl butyral, more preferably it contains polyvinyl butyral plasticizers.

Preferably, the particulate particles are glued with a thermosetting binder before gluing and pressing. More preferably, this gluing is done with melamine formaldehyde, urea formaldehyde, melamine-urea formaldehyde, phenol formaldehyde, phenol-urea formaldehyde, MDI (methylene diphenyl diisocyanate), pMDI (“polymeric methylene diphenyl diisocyanate”), a binder or a thermosetting agent obtained by thermosetting agent. More preferably methylene diphenyl diisocyanate (MDI) containing a polyol or a polycaprolactam or other flexible chain extender; or polymeric methylene diisocyanate (pMDI) containing a polyol or a polycaprolactam or other flexible chain extender.

Gluing the particulate particles before gluing and pressing has a number of advantages. The water resistance of the plate material is better. Gluing also prevents delamination when pressing. The thermoset provides the internal bonding during the pressing phase when the second binder becomes thermoplastic.

According to a further particularly preferred option, which may or may not be combined with the above special option, the second material layer comprises, in addition to the second binder and the particulate particles, a further fraction of glue, preferably a thermosetting glue and / or an glue selected from the series of urea formaldehyde, melamine urea formaldehyde, (p) MDI, polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), polyurethane, acrylate dispersion or latex dispersion. These thermosetting resins can be emulsified if necessary to improve processing. Adding such glue can increase internal bonding and water resistance, as well as improve the ability of the second material layer to maintain a pressed-in structure, for example as may be the case when the sheet material is used as a substrate in a DPL press. As mentioned above, the particulate particles, in particular the wood chips, of the second material layer can be impregnated with, for example, glycerol. Such impregnation increases the efficiency of the adhesive fraction, so that an acceptable sound can be obtained in combination with an acceptable internal bonding. Preferably, the aforementioned second material layer comprises 0.5 to 5% by weight of such adhesive, more preferably 2 to 4% by weight.

Preferably, the first and the second material layer are consolidated and bonded together in one and the same pressing operation, more preferably the polycondensation moisture formed in the reaction of the first binder is absorbed into the wood fibers.

Preferably, a density profile is formed over the thickness of the plate material, which in each case exhibits a peak density near the surfaces.

Preferably, one peak is formed in the material of the first material layer, while a second peak is formed in the material of the second material layer.

Preferably the peaks are of the same height or substantially the same height, for example the peak near one surface is at most 10 percent higher than the peak near the other surface.

The density between the aforementioned peaks preferably remains below the level of the aforementioned peaks.

A symmetrical or nearly symmetrical density profile is thus obtained in the new plate material, similar to the density profile of HDF plate material from the prior art.

According to the present invention, at least one of the peaks is located in the aforementioned second material layer.

Because this density peak is in softer material, a tapping sound is obtained that is very similar to that of real wood.

The present inventors have realized that they could make use of the inhomogeneous hardening and compaction that occurs in a standard HDF production, with the difference that one of the density peaks is formed in the aforementioned second material layer, and therefore a less irritating sound. produces.

The preservation of the density peak in the first material layer on the other surface of the plate material is interesting for the strength of any coupling agent that may be present there.

For example, it is possible for a lower groove lip in a tongue-and-groove coupling system to be at least partially made of this high-density material, so that a higher connection strength can be obtained.

According to a particularly independent aspect, the present invention relates to a plate material having a density profile that shows a peak near both surfaces, and wherein the density between said peaks remains below the level of said peaks, characterized in that a first of said peaks is present. is in a material layer comprising thermosetting binder, while a second of said peaks is in a material layer comprising thermoplastic or elastomeric binder. It goes without saying that a plate material according to such a special aspect can further exhibit the characteristics of the first independent aspect of the invention and / or of the preferred embodiments thereof. Preferably, the density between the aforementioned peaks remains above 80% of the average density of the plate material. The average density of the plate material is preferably minimum 550 kg / m 3, or better still minimum 700 kg / m 3 or minimum 800 kg / m.

According to the most preferred embodiment of the present invention in its first aspect, the sheet material consists of a first and a second material layer, and is essentially free of further material layers. The binder of the first material layer is melamine urea formaldehyde and the wood particles in the first material layer are wood fibers. The first binder makes up 3 to 20 weight percent of the first material layer, preferably about 14 weight percent. The first material layer has a thickness of at least 70% of the thickness of the plate material. The binder of the second material layer is polyvinyl butyral (PVB) and the wood particles in the second material layer are wood chips. The content of polyvinyl butyral (PVB) in the second material layer is between 10 and 60 weight percent, preferably between 25 and 50 weight percent, or more preferably between 35 and 50 weight percent. The content of wood chips in the second material layer is between 40 and 75% by weight, or better still between 50-65% by weight. Preferably, the second material layer also comprises a fraction of glue. This fraction of glue can be provided by gluing the wood chips. Preferably, the glue ratio of the wood chips is

2.5 to 7.5 weight percent, and more preferably 4 to 6 weight percent, and more preferably 2 to 4 weight percent. The glue can be, for example, MDI, UF, MUF, or polyurethane. The second material layer has a thickness of 30% or less of the thickness of the plate material. On the basis of the composition of the above most preferred embodiment, the inventors have obtained a plate with an internal bonding strength of

0.5 to 1.5 N / mm, and even from 0.7 to 1.5 N / mm?, Measured according to EN 319: 1993.

The material of the different material layers of the plate of the first independent aspect is preferably superimposed on each other by means of multiple scattering operations.

A method for manufacturing the plate material of the first independent aspect, in itself forms a particularly independent aspect of the invention, and preferably comprises the following steps: - optionally the step of providing glue on the particulate particles of the second material layer .

For example, wood chips can be mixed and glued with 2 to 7 weight percent (and preferably 2 to 4 weight percent) of a thermosetting adhesive, such as phenol formaldehyde, urea formaldehyde, melamine urea formaldehyde, MDI (methylene diphenyl diisocyanate), polyurethane dispersion or acrylate dispersion; the step of providing particles based on the second binder.

For example, particles can be provided with polyvinyl butyral (PVB), for example recycled polyvinyl butyral (PVB); - optionally the step of mixing the particulate particles into the particles of the second binder; - the step of depositing the wood particles of the first material layer, and the first binder, on a transport device or in a mold.

Preferably, melamine uream formaldehyde (MUF) or methylene diphenyl diisocyanate (MDI) glued wood fibers are deposited, optionally the step of compacting the deposited wood particles and the first binder; - optionally the step of wetting the already deposited wood particles and the first binder with, for example, water and / or glue; thus, adhesion and internal bonding can be improved; - the step of depositing particulate particles and binder particles of the second material layer on the deposited wood particles and the first binder.

Preferably, this step is carried out on the basis of one or more scattering operations. - optionally the step of wetting the whole of deposited materials with for instance water and / or glue; thus, adhesion and internal bonding can be improved;

- the step of compacting and heating the whole of deposited materials. Preferably, the compaction and the heating takes place in a double belt press, preferably in only one double belt press. Preferably, the material of the first and second material layers is heated and compacted at the same time. During the same operation, the adhesion is preferably also obtained between the two material layers.

Preferably, a coherent plate material is obtained which consists of two material layers, namely the aforementioned first material layer and the aforementioned second material layer. The inventors have determined that the presence of the second binder of thermoplastic and / or elastomeric nature can create a flat surface during the compacting and heating step. The risk of possible imprinting or telegraphing of irregularities in a deposited layer to the surface of the second material layer is limited. Compared to a prior art MDF or HDF board material, no or fewer sanding operations are required to obtain a smooth laminable surface. The thermoplastic or elastomeric second binder flows between the larger particulate particles, in particular the wood chips, and thus smooths out the resulting surface.

It is clear from the above that the sheet material of the invention can be obtained in one pressing operation, and that separate pressing operations or additional gluing operations are superfluous.

For the step of depositing particulate particles and binder particles of the second material layer on the deposited wood particles and the binder of the first material layer, various concrete possibilities exist, some of which are listed below, without intending to be exhaustive.

According to a first concrete possibility, a mixture of glued wood chips and polyvinyl butyral (PVB) particles are spread by means of one and the same spreading operation.

According to a second concrete possibility, two separate scattering operations are used. In a first scattering operation, glued wood chips are scattered and in a second scattering operation polyvinyl butyral (PVB) particles are scattered.

According to a third concrete option, work is carried out as in the second option, but a third separate spreading operation is added in which wood chips provided with glue are sprinkled.

According to a fourth concrete option, work is carried out as in the third option, but unglued wood chips are sprinkled in the third separate spreading operation.

According to a fifth concrete option, a sprinkling operation is used in which a granulate or compound of wood chips and polyvinyl butyral (PVB) is sprinkled.

According to a sixth concrete option, work is carried out as in the fifth option, but a second separate spreading operation is provided in which unglued wood chips are spread.

According to a seventh concrete option, the operation is carried out as in the sixth option, but in the second separate spreading operation, wood chips provided with glue are sprinkled.

According to an eighth concrete possibility, two or more scattering operations are used in which a granulate or compound of wood chips and polyvinyl butyral (PVB) is scattered, whereby the compounds in the different scattering operations may possibly have a different composition. The difference in composition can be expressed by different ratios in weight percentages between the binder and the particle, and / or by different shapes and / or particle sizes of the binder and / or the particle in the different compounds.

According to a first important example of this, the composition of the compound from the first spreading operations can preferably be attuned to obtaining a sufficient adhesion to the material of the first material layer, while the compound from, for example, a second or subsequent spreading operations can be adapted to the obtaining a smooth surface with a limited risk of imprinting scattered irregularities from underlying layers to the surface of the plate material. According to a second important example of this, the size of the wood chips or particulate particles of the second material layer is varied, preferably such that from two consecutive scattering operations, a first scattering operation deposits coarser wood chips or particulate particles than a second scattering operation. According to a third important example of this, the melting temperature of the second binder is varied, preferably such that in two consecutive spreading operations, a first spreading operation exhibits a lower melting binder than a second spreading operation.

It is noted that the combination of different sizes and shapes of compounds / granulates can give rise to an improved sintering, such that the obtained plate material forms a more cohesive whole, for example with an internal bond of 0.7 N / mm? or more. It is further noted that each of the scattered sub-layers of the second material layer can be individually adjusted with its own specific binder-to-particle ratio, glue proportion and particle size distribution. Although the concrete possibilities have been described above with wood chips as particulate particles and polyvinyl butyral (PVB) as binder, these can of course, mutatis mutandis, be performed with other particulate particles and second binders.

Although particulate polyvinyl butyral (PVB) or a granulate / compound is mentioned above, the polyvinyl butyral (PVB), or another second binder, can be prepared in various other ways. For example, the PVB can be micronized, machined, cryogenically machined, micro-extrusion, micro-pelleted or granulated as previously mentioned. Regardless of the way in which the particulate polyvinyl butyral (PVB) is obtained, it preferably shows an average particle size as expressed with the d50 value measured by laser light diffraction granulometry (ISO013320 (2009)), from 0.1 to 2 mm. The lowest range is obtained for example by micronization, while the larger particles can be obtained by means of extrusion.

In all the above concrete possibilities, as mentioned above, water and / or glue can be sprayed on the material already deposited in order to carry out one or more of the sprinkling operations mentioned there. For example, the adhesive can be MUF, UF, MF, MDL PVA or PVAc. Water can promote heat transfer in the compacting and heating step, so that a more cohesive whole, i.e. a higher internal bond according to EN 319: 1993, can be obtained. A similar result can be achieved by spraying with glue.

With the same object as in the first independent aspect, according to a third independent aspect the present invention relates to a floor panel with a substrate obtained from a sheet material according to the first independent aspect and / or according to the above-mentioned particular independent aspect and / or obtained by means of a method according to the second independent aspect and / or having the features of one or more preferred embodiments of each of these aspects. It is clear that such a floor panel can better imitate a real wood floor panel in that the sound in use is closer to the sound of a wood floor panel, and / or that such a floor panel, independent of the imitation it forms, is less irritating. produces sound.

Preferably, the floor panel comprises a decorative top layer applied to the surface of the aforementioned plate material formed by the aforementioned second material layer. It is clear that in such a case the influence on the produced sound is most striking. Moreover, the possibility of structuring the second material layer can best be used in this way. Also the rebound effect or creep back effect after impact on this layer is best utilized in a configuration according to the presently preferred embodiment.

Preferably, the aforementioned decorative top layer comprises a printed paper sheet and a transparent or translucent layer placed above it.

Said transparent or translucent layer preferably comprises plastic material which has been subjected to at least one thermal curing.

Such plastic can be smoothly textured and / or structured, for instance by means of a heated structured mold or press element.

Preferably, thermally cured acrylic resin or an unsaturated polyester is used for the aforementioned plastic.

Such plastic is tough, and the risk of breakage in the relevant plastic layer on impact is limited.

This risk is in itself higher than with the laminate floor panels from the prior art due to the presence of the aforementioned second material layer.

The use of the aforementioned plastics in the top layer makes it possible to make the second material layer softer and / or more resilient than would be the case with, for example, a top layer based on melamine.

Moreover, the second material layer can exert a restorative effect on any indentations due to impact on the top layer.

After all, the inventors have established that any indentations on the surface of the top layer can completely or partially disappear due to the aforementioned second material layer of the plate material.

This is especially the case when the second material layer comprises polyvinyl butyral (PVB) as second binder and wood chips as particulate particles.

The use of a top layer based on thermally cured acrylic resin or an unsaturated polyester has much less residual tensile stresses than is the case with, for example, a top layer based on melamine resin, as is the case with the laminate floor panels of the prior art.

Preferably, said decorative top layer has a relief with structural features showing a depth greater than the thickness of the decorative top layer.

Preferably, said structural features form, at least on one or more edges of the floor panel, lower edge areas, such as edge areas in the form of a chamfer.

In the case of lower edge areas, whether or not in the form of a chamfer, the decor preferably extends up to the relevant upper edge.

Preferably, the relevant top edge and / or the bottom side of the decorative top layer at the location of the top edge, is at a horizontal level which extends below the level of the aforementioned second material layer.

In such a way the second material layer is largely shielded from influences such as possible moisture penetration via the seam between the upper edges of adjacent floor panels.

The relevant structural characteristics can be obtained at least on the basis of a heated pressing operation with a structured pressing element.

During such a pressing operation, the plastic of the top layer can be cured, and optionally the binder of the second material layer can be melted or at least made flexible so that the second material layer follows the pressed-in structure of the top layer.

It is also possible that, in combination with a heated pressing operation, the plate material has a structure before proceeding to the pressing operation, for example because the second material layer has been worked locally, for example by means of a machining operation, and / or because the second material layer is not uniform. is applied to the first material layer.

For example, a technique as known per se can be applied for MDF or HDF substrates from WO 2017/072657. It is clear that the aforementioned decorative top layer can also be of a different type than a top layer comprising a printed paper sheet and a transparent or translucent layer placed above it.

For example, the decorative top layer may comprise a wood veneer, a, preferably printed, plastic foil, such as a printed PVC foil with a PVC-based wear layer applied above it, a printing formed directly on the substrate with a transparent lacquer layer, such as an acrylic-based lacquer layer, applied above it, or the like more.

In general, the aforementioned decorative top layer may comprise a UV cured or electron beam (EB) cured transparent plastic, such top layer may then comprise a printed paper sheet or a print formed directly on the substrate.

It is clear that, where in the above reference is made to a printing formed directly on the substrate, it is not precluded that the substrate will be prepared on the basis of one or more base layers or primers prior to printing.

A "print formed directly on the substrate" here refers to a print that has been formed by depositing ink or other colorant in a pattern on the substrate and optionally the base layers and primer layers, preferably by means of a printing process such as rotogravure, screen printing or inkjet printing.

It is noted that by means of the present invention according to one or more of the above aspects thereof, an additional acoustically acting layer, namely said second material layer, can be formed in a MDF or HDF production line of the prior art, whereby it is acoustically working layer changes the frequencies of the surface sound so that the surface mimics the sound of real wood. At the same time, the compressibility of the sheet material has been increased, so that more complex and deeper surface structures can be applied by means of a standard kurztakt press (single daylight press) and structured press elements. This allows the appearance of a real wooden floor to be simulated even better. The inventors have further established that the use of the second material layer according to the invention improves the performance (for example scratch and abrasion resistance) of an acrylic-based top layer compared to such a top layer applied on an MDF or HDF substrate. As mentioned above, it is preferably a thermally cured acrylic-based top layer, such as, for example, a top layer of the type described in the applicant's BE 2018/5787, which was not published at the time of submission. Preferably, the top layer comprises, for example the wear layer applied over a printed decor, a thermally cured acrylic resin or unsaturated polyester resin. Preferably, the aforementioned acrylate resin is cured by a thermally initiated radical cross-link reaction. The aforementioned curing preferably comprises at least one crosslinking of the carbon double bond present in the acrylate resin. The aforementioned wear layer is preferably obtained on the basis of a mixture of acrylate resin and a thermo-initiator or optionally a mixture of a thermal initiator and a photo-initiator. The aforementioned thermo-initiator is preferably an organic peroxide, preferably benzoyl peroxide, lauryl peroxide, ketone peroxide or diacyl peroxide or an initiator selected from the list of peroxy ester, peroxy ketal, hydroperoxide, peroxydicarbonate, peroxymonocarbonate and AZO polymerization initiator. The foregoing mixture preferably comprises 0.1-5 parts of thermo-initiator per 100 parts of acrylate resin, and preferably 0.5-2 parts of thermo-initiator per 100 parts of acrylate resin. The wear layer can be cured uniformly or substantially uniformly over its entire thickness. As aforementioned, the thermal cure preferably comprises chemical cross-linking, preferably of the carbon double bonds present in the acrylate resin. The aforementioned decor may comprise a plastic backing sheet, such as a paper sheet, this plastic comprising carbon double bonds, for example selected from the list of polyurethane, urethane-acrylic copolymer, acrylate, latex, polyether and polyester, optionally in combination with a crosslinking agent. Alternatively or additionally, plastics without double bonds can also be used, e.g. polyurethane dispersions.

Where there is a top layer comprising acrylate resin, use is preferably made of aliphatic acrylate resin and / or the relevant acrylate resin can at least be obtained on the basis of a multifunctional acrylate monomer and / or oligomer, such as a hexafunctional acrylate oligomer and / or at least obtained are based on a monofunctional or difunctional acrylate monomer and / or oligomer and / or are at least obtained with a chemically modified acrylate, such as with a fluoro acrylate. A method for manufacturing covered panels or floor panels having the features of the invention is preferably further characterized in that the panels comprise at least one substrate based on a plate material according to the invention, and have a top layer applied thereto, the said top layer being at least comprises a decor and a transparent or translucent wear layer and the method comprises at least the following steps: - the step of applying an acrylic resin containing a thermo-initiator to said decor; it is preferably an acrylate resin as described above; and - the step of at least partially curing said acrylic resin by means of a heated pressing operation to form at least a portion of said wear layer. Preferably, the pressing operation is carried out on the basis of a Kurz-stroke press and / or the pressing operation is carried out at a temperature of 120 to 220 ° C and / or at a pressure of 10 to 80 bar. Preferably, the pressing operation is carried out with the aid of a structured pressing element. Preferably, said pressing operation is performed on a stack comprising at least the substrate,

the decor and acrylic resin. Preferably, the step of applying an acrylic resin to the aforementioned decor is performed while the decor is already part of a stack comprising at least the substrate and the decor. Preferably, the aforementioned decor comprises a carrier sheet, such as a paper sheet, and the method comprises at least the further step of providing the relevant carrier sheet with plastic, such as at least applying a water-based or a water-based UV-curable plastic to the aforementioned carrier sheet. . Optionally, the acrylic resin can already be applied to the decor paper.

According to a variant of the present invention, it is also possible that the above described possible compositions of the second material layer are used to form the full thickness of a plate material, or at least more than half the thickness of such plate material. According to a fourth independent aspect, the present invention therefore relates to a plate material having at least one, and preferably only one, material layer, this material layer being substantially composed of particulate particles glued and pressed by means of a binder, wherein the binder is thermoplastic. and / or elastomer. The inventors have found that such a plate can be extremely flexible and can find or offer special applications and design freedom, for example in the manufacture of furniture. Such plate material can be thermally formed and, moreover, the plate material obtained is easy to recycle. The final sheet material can have a thickness of 2 to 20 mm, preferably 6 to 15 mm. It is clear that the material layer in question here preferably forms 50 percent of the thickness of the plate material or more, preferably at least 75%, or even constitutes the full thickness or almost the entire thickness of the plate material.

According to another variant, the composition of the aforementioned second material layer can also be used as a substrate for a decorative covering material, such as for a casing material. To this end, according to an independent fifth aspect, the invention further relates to a decorative covering material with at least one decorative top layer which is applied to the surface of a material layer, this material layer consisting essentially of particulate particles glued and pressed by means of a binder, wherein the binder is thermoplastic and / or elastomer. In this way a flexible thin covering material is obtained, for example with a thickness of 1 to 5 mm, and more preferably 1.5 to 3 mm. Such coating material can be thermally formed, can be completely waterproof and can be made recyclable. Preferably, the binder employed in the fourth and / or fifth aspect is polyvinyl butyral (PVB).

Preferably, the particulate particles used in the context of the fourth and / or fifth aspect are wood chips, preferably having the dimensions, d50 values, stated in the context of the first aspect. However, wood fibers can also be used as particulate particles.

Preferably, the particulate particles used in the context of the fourth and / or fifth aspect are glued with a thermosetting binder for gluing and pressing. More preferably, this is done with melamine-formaldehyde, urea-formaldehyde, melamine-urea-formaldehyde, phenol-formaldehyde, phenol-urea-formaldehyde, MDI (methylene diphenyl diisocyanate), pMDI (“polymeric methylene diphenyl diisocyanate”), or by reacting a thermosetting agent with an acrylate resin contains. More preferably with methylene diphenyl diisocyanate (MDI) containing a polyol or a polycaprolactam or other flexible chain extender, or with polymeric methylene diisocyanate (pMDI) containing a polyol or a polycaprolactam or other flexible chain extender.

In an important example of the fourth and / or fifth aspect, 35 to 55 weight percent polyvinyl butyral (PVB) is used as the binder and 45 to 65 weight percent wood chips as particulate particles.

It is also noted that, where in the above reference is made to “internal bond”, the value, as determined on the basis of EN 319: 1993, is for the resistance to forces perpendicular to the surface of the plate material.

It is further noted that the second material layer as mentioned in foregoing independent aspects and the preferred embodiments thereof may still contain additives such as fire retardant additives, water resistant additives (eg wax, paraffin, and the like), adhesion promoters (eg silane based additives), reinforcement materials (eg glass fibers, basalt fibers, etc.), fragrance molecules (eg to mimic the smell of real wood), fillers (such as perlite, glass spheres, CaCOs, etc.), colorants (eg to imitate the thickness of a top veneer layer) mimic). The thickness of the second material layer is preferably

0.3 to 3 mm.

In case the plate material of the invention is used in a floor panel, as is the case in the context of the third independent aspect, this floor panel is preferably provided on at least two opposite edges with coupling means which allow such a floor panel to be able to reach the relevant edges. are coupled to a similar floor panel, whereby a mutual locking is created at the respective coupled edges both in a vertical direction perpendicular to the plane of the coupled floor panels, and in a horizontal direction perpendicular to the relevant edges and in the plane of the coupled floor panels. The relevant coupling means are preferably substantially formed in the aforementioned first material layer. Any contact near the top edge may be formed on the aforementioned second material layer. Preferably, the aforementioned coupling parts are substantially in the form of a tongue and a groove, which are provided with locking parts that hinder the movement of the tongue and the groove apart in the aforementioned horizontal direction. For example, said locking members may include a recess defined by a protruding portion on one or both lips defining the said groove and a portion of the tongue cooperating therewith. It is clear that the aforementioned locking in the vertical direction is realized by the cooperation between the tongue and the groove.

As mentioned in the introduction, the inventors have come to the conclusion that the presence of a peak in the density near the surface of an MDF or HDF board is largely responsible for the generation of irritating noise.

Therefore, as a first alternative to the sheet material and floor panels of the present invention, it is possible to sand the MDF or HDF sheet to the level below the peak density at least at the surface intended to be walked on. Preferably, this sanding operation is carried out on both surfaces, so that a stable plate is again obtained. It is therefore clear that according to a sixth independent aspect the present invention also relates to a method for manufacturing floor panels, said method comprising at least the following steps: - the step of manufacturing a wood fiber board of the HDF type, namely with an average density of at least 800 kg / m °; it is preferably a wood fiber board based on wood fibers and UF, MF, MUF or pMDI resin; the step of sanding one or both surfaces of the aforementioned wood fiber board to a depth of 0.3 to 1 millimeter, preferably 0.3 to 0.6 or about 0.4 mm; - the step of applying a decorative top coat to at least one of the sanded surfaces. The decorative top layer is preferably a wood veneer, a plastic foil, preferably printed, or a decorative top layer based on acrylic resin, preferably thermally cured acrylic resin, of the type as described in detail above, inter alia with reference to BE 2018 / 5787, or unsaturated polyester resin. As an alternative to the acrylic resin, for example: a dual cure aliphatic acrylate lacquer (i.e. an aliphatic acrylic lacquer that is cured by a combination of thermal and UV curing), a solvent-based urethane acrylate lacquer, UV or electron beam (EB) curing acrylic lacquers.

As a second alternative to the board material and floor panels of the present invention, it is therefore possible to produce the MDF or HDF board with a more uniform density profile. This is possible, for example, by preheating the fiber mat to be pressed, for example by means of microwaves. It is therefore clear that according to a seventh independent aspect the present invention also relates to a method for manufacturing floor panels, this method comprising at least the following steps: - the step of providing a mat of glued wood fibers, preferably glued with MF, MUF, UF, or pMDI, - the step of heating said mat, preferably by means of microwaves, prior to compression thereof; - the step of pressing the aforementioned mat into a wood fiber board with an average density of at least 700 kg / m? and better still at least 800 kg / m; - the step of applying a decorative top layer to at least one of the surfaces of the aforementioned fiberboard. The decorative top layer is preferably a wood veneer, a plastic foil, preferably printed, or a decorative top layer based on acrylic resin, preferably thermally cured acrylic resin, of the type as described in detail above, inter alia with reference to BE 2018 / 5787, or unsaturated polyester resin.

With the insight to better demonstrate the characteristics of the invention, some preferred embodiments are described below, by way of example without any limiting character, with reference to the accompanying drawings, in which: figure 1 shows a floor panel with the characteristics of the invention; figure 2 represents a cross-section according to the line TLT shown in figure 1, figure 3 shows on a larger scale a view of the area indicated by F3 in figure 2, in a coupled state of two such floor panels; figure 4 represents a view to a larger scale of the area indicated by F4 in figure 3; figure 5 schematically represents some steps in a method for manufacturing a plate material with the features of the invention; figure 6 schematically represents a few steps in a method for manufacturing a floor panel with the features of the invention;

figure 7 shows on a larger scale a view of the area indicated by F7 in figure 5 for a variant; and - figure 8 shows a graph with the density of the plate material from figures 1 to 4 as a function of its thickness.

Figure 1 shows a decorative panel, more particularly a floor panel 1, in accordance with the invention. The panel 1 is rectangular and elongated and includes a pair of opposite short edges 2-3 and a pair of opposite long edges 4-5.

Figures 1 to 3 show that both pairs of opposite edges 2-3-4-5 are provided with mechanical coupling means 6 mainly implemented as a tongue 7 and a groove 8 delimited by an upper lip 9 and a lower lip 10, wherein the tongue 7 and the groove 8 are mainly responsible for the locking in a vertical direction V1, and the tongue 7 and the groove 8 are provided with additional locking parts 11-12, which are mainly responsible for the locking in a horizontal direction H1. Preferably, the locking parts comprise a protrusion 11 on the underside of the tooth 7 and a recess 12 in the lower groove lip 10, bounded by a protruding portion 13. The coupling means 6 shown in Figures 1 to 3 permit at least one coupling by means of a rotational movement W around the relevant edges 2-3-4-5 and / or a coupling by means of a sliding movement S in a substantially horizontal manner of the edges 2- 3-4-5 to be coupled towards each other.

Figure 3 clearly shows that the decorative panel 1 comprises a substrate 14 on which a decorative top layer 15 is provided. The special feature of the floor panel 1 from figures 1 to 3 is, among other things, that the substrate 14 is obtained on the basis of a plate material 16 according to the first aspect of the invention. For this purpose, the plate material 16 comprises a first material layer 17 which forms more than half the thickness T of the plate material 16 and is composed mainly of wood particles glued and pressed by means of a first binder. In this case, the first material layer 17 has the structure of a typical HDF plate.

Namely, it is composed of MUF glued and pressed wood fibers 18. Figure 4 clearly shows that the plate material 16 furthermore has a second material layer 19 on the surface, this second material layer 19 being mainly composed of a second material layer 19. binder glued and pressed particulate particles 20. In the present case, the second binder is thermoplastic, more in particular polyvinyl butyral (PVB) obtained by recycling glass.

The particulate particles 20 are wood chips with a particle size of

500 μm or more, as expressed with the D50 value measured with laser light diffraction granulometry according to ISO13320 (2009). According to a concrete example, the wood chips show the particle size distribution below.

Size | weight | Mass (mm) (g) (%)> 3 21.5 | 4174757 2.5-3 48.5 | 9.417476 2-2.5 29.5 | 5.728155 1.4-2 | 189.5 | 36.79612 1-1.4 63.5 12.3301 <1 162.5 | 31,5534 The thickness T1 of the aforementioned first material layer 17 is at least three times the thickness T2 of the aforementioned second material layer 19. The plate material 16 consists of the aforementioned first material layer 17 and second material layer 19, and thus has no further material layers than the aforementioned first and second material layer 17-19. The aforementioned decorative top layer 15 is applied to the surface of the plate material 16 formed by said second material layer 19. The aforementioned decorative top layer 15 comprises a printed paper sheet 21 and a transparent or translucent layer 22 arranged over it. In this case, the transparent or translucent layer 22 comprises transparent layer of plastic that has been subjected to at least one thermal curing, more in particular thermally cured acrylic resin or unsaturated polyester, preferably cured by means of an at least thermally initiated radical cross-link reaction.

In the representation of Figure 4, the printed paper sheet 21 is shown. Preferably, this paper sheet 21 is provided in its core with modified or unmodified melamine resin. In this example, a plastic comprising double carbon bonds, such as polyurethane, is provided on both surfaces of the paper sheet 21. As an alternative to this polyurethane, for example, a water-based polyurethane dispersion can be used. Above this, as already mentioned, the transparent or translucent wear layer 22 is present. In the top layer 15, at a position above the printing 23, hard particles 24, such as aluminum oxide particles, are further provided for obtaining an improved wear resistance.

Figures 2 and 3 clearly show that the aforementioned decorative top layer 14 has a relief with structural features showing a depth greater than the thickness T3 of the decorative top layer 15. At the edges of at least two opposite sides, the floor panel has lower edge regions 25, in this case. case in the form of a chamfer. The printing 23 or decor extends up to the relevant top edge

26. The bottom side of the decorative top layer 15 is located at the top edge 25 at a horizontal level L which extends below the level of the second material layer 19.

Figure 5 schematically represents a method for manufacturing a plate material 16 having the properties of the invention. In the example, it concerns a method that is carried out on the basis of a production line 27 which essentially corresponds to a typical MDF or HDF production line. The starting point here is a material mass 28 for the aforementioned first material layer 17, which in a preliminary step SO is composed at least on the basis of the aforementioned first binder and the aforementioned wood particles. In this case, both components are simultaneously supplied to a spreader 29 in the form of wood fibers 18 previously provided with the first binder, namely polycondensation glue, wood particles, in particular polycondensation glue, for example MUF.

The spreading machine 29 of such a production line 27 can be constructed in any way. In the example a spreader 29 is used as is known per se from WO 03/053642. The spreader 29 of the example is provided with several agitating elements 30 which set the glued wood fibers 18 in motion in the spreading chamber 31. On the basis of the wood fibers 18 exiting the spreading chamber 31 at the bottom, the material mass 28 is assembled on the surface below. standing conveyor or conveyor belt 32. For further description of such spreader 29, reference is made to the aforementioned international patent application. Other types of spreading machines are of course also suitable, such as, for example, the spreading machines described in the international patent applications WO 99/36623 and WO 2005/044529. Seen in passage, a so-called scalpel roller 33 is located after the spreader 29, which removes any excess wood fibers 18 from the material mass 28, after which a material mass 28 with a flat or quasi-flat top surface is obtained. It is noted that it is not necessary to work with such scalpel roll 33. In passage after the aforementioned scalpel roller 33 is a compaction device or pre-press 34 in which the composite material mass 28 is gradually compacted prior to the actual hot pressing in step S2 to a state in which it can be transported in a simpler manner compared to the unsealed composite. material mass 28. For this purpose, the composite material mass 28 is preferably conveyed, as shown here, between press belts 35 during step S1, these press belts 35 having a continuously decreasing intermediate distance. In this pre-compaction in the pre-press 34, preferably no heat is supplied and / or, preferably, the first binder present is not yet activated or only partially activated. Rather, the precompression preferably involves at least partial removal of the gases, such as air, present in the composite material mass 28.

After the aforementioned precompression has been performed in step S1, granules 36 are applied to the material mass 28 of the first material layer 17. The granules in question 36 comprise the aforementioned second binder and the particulate particles 20, in this case polyvinyl butyral (PVB) and wood chips, optionally supplemented with a glue fraction, for example pMDI. For this purpose, seen in a passage after the spreader 29, there is a device 37 for applying the aforementioned granules 34 to the material mass 28. In this case, the device 37 carries out a spreading operation. For this purpose, a spreader can be used as known per se from GB 1,003,597 or GB 1,035,256. As shown in Figure 5, such spreader may comprise a receptacle 38 in communication with a metering roller 39 that carries the granules 36 out of the receptacle 38. Such a dosing roller 39 preferably has a structured design, the granules 36 being then entrained mainly via the lower structural parts of the dosing roller 39. Such a spreading device preferably further comprises a device 40 which releases the granules 36 from the aforementioned dosing roller 39. In this case, a brushing device is used for this purpose. A sufficiently homogeneous spreading pattern can be achieved by means of such a spreading device. After the compaction device or pre-press 34, and the device 37, the actual pressing device 41, viewed in flow direction, is located, in which the composite material mass is pressed under the influence of heat. The temperature used may be, for example, between 100 ° C and 150 ° C and the pressure applied may be, for example, on average between 4 and 10 bar, but short-term peak pressures of up to 40 bar are not excluded. Preferably, the binder present in the granules 36 is melted in this pressing device 31, or at least brought above its glass transition temperature. Preferably, the activation of the first binder present on the wood fibers 18 also takes place here. In the case of a polycondensation adhesive, water or rather steam can be generated in this pressing device 41.

The press device 41 shown here is of the continuous type, namely of the type in which the composite material mass is transported between press belts 42 and / or is gradually pressed. A pressure and / or temperature curve can be set in the passage of such a pressing device 41. By means of this pressing device 41, the density of the already partially compacted composite material mass 16 can be at least doubled. It is clear that the method of the invention can also be carried out with other pressing devices, such as, for example, with a vapor pressure press, with a multi-level press or with a so-called Kurz-stroke press. With these other pressing devices 41, the applied pressure and / or temperature can be adjusted as a function of the time that the relevant mass of material remains in the pressing device 41. It is clear from the above that Figure 5 is an example of the fifth concrete option described in the introduction for the step of depositing particulate particles 20 and binder particles from the second material layer 19. It is clear that the other concrete options mentioned there can also be used in a production line. 27 can be used, by varying the content of the container 38 and / or the number of devices 37 according to the desired possibility. Preferably, all devices 37 or spreading operations for the second material layer 19 are located between the pre-press 34 and the actual press 41.

Figure 6 schematically represents a few steps in a method for manufacturing the floor panel 1 from figures 1 to 4. In the example, a decorative top layer 15 is used which comprises at least one paper sheet 21. The paper sheet 21 is provided per se with a printing 23. In a first step S3, the paper sheet 21, more particularly a paper web from which the paper sheet 21 will later be obtained by cutting, is provided with plastic 43. To this end, the paper web is unrolled and impregnated into the core by means of a first plastic 43. The core impregnation can limit the risk of splitting of the paper sheet 21 in the final coated panel 1. In the example, this core impregnation takes place in two sub-steps, namely a first sub-step S3A in which plastic 43 is applied by means of a roller 45, and a second sub-step S3B in which the paper sheet 21 is immersed in a bath 46 with the relevant plastic 43. In the example, the plastic 43 is that in the first sub-step

S3A and the same is applied in the second sub-step S3B. However, it is also possible that the plastic applied in the first and the second sub-step are different from each other, independent of the concrete application technique that is used. Between the first sub-step S3A and the second sub-step S3B, the paper sheet 21 performs a path 47 which allows sufficient penetration of the first plastic 43 applied during the first sub-step S3A. As the first plastic 43, an optionally modified melamine-formaldehyde resin, optionally modified urea-formaldehyde resin or optionally modified melamine-urea-formaldehyde resin can be used.

Figure 6 further shows that, after the aforementioned core impregnation, aluminum oxide particles 24 can be applied in a third sub-step S3C, for example, as here, by a scattering operation. This is followed in a fourth sub-step S3D, preferably, a drying operation in a hot air oven 48. Optionally, in a fifth sub-step S3E, on the side of the printing 23 and / or the side of the paper sheet 21 that is intended for the wear layer 22, an interlamellar coating 44 can be applied which increases compatibility with the wear layer 22 to be formed from thermoset acrylic resin or unsaturated polyester. Such interlamellar coating 44 may, for example, consist of a water-based polyurethane coating, a water-based UV-curable substance and / or carbodiimide. During the same step S3E, or in a separate step, a coating 44 may also be applied to that side of the paper sheet 21 intended to be facing the substrate 14. Such coating 44 aims to bring about a better adhesion to the substrate 14. Alternatively, such coating 44 may also have the purpose of providing sound damping. In the latter case, use is preferably made of polyurethane, for example aromatic polyurethane or thermoplastic polyurethane (TPU). After the interlamellar coating 44 has been applied, a drying operation similar to that of the fourth sub-step S3D can be performed again, as in the example.

In a seventh sub-step S3F, the treated paper sheet 21 in this example passes through a cooling roller 49, and the paper web is divided into sheets.

In a second step SS a stack 50 is formed comprising at least the substrate 14 and the paper sheet 21 with the printing 23, obtained in step S3. Preferably, a method of the invention comprises at least the third shown step S5, namely the step of applying an acrylic resin containing a thermo-initiator above the printing 23 or the decor, and the fourth shown step S6, namely the step of at least partially curing the aforementioned acrylic resin by means of a heated pressing operation.

In the third step S5, an acrylic resin with a thermo-initiator is also applied to the underside 51 of the substrate 14 to form a backing layer 52. It is understood that here the third step S5, namely the step of applying the acrylic resin is performed while the paper sheet 21 with the printing 23 or the decor is already part of a stack 50 comprising at least the substrate 14 and the decor or the paper sheet 21 with the printing 23.

In the example shown, the pressing operation is carried out on the basis of a so-called kurz-stroke press 53, and more especially on the basis of a structured press element 54 or press bleach.

The pressing operation is performed on a stack 50 comprising the substrate 14, the paper sheet 21 with the printing 23, the acrylic resin of the wear layer 22 and the backing layer 52.

During the pressing operation, the structure 55 of the pressing element 54 is copied into the surface of the wear layer 22. Figure 7 shows a variant for the device 37 shown in Figure 5. This concerns a device 56 comprising one or more devices 37A-37B- 37C or spreader devices, which deposit particulate particles, first binder and / or granules on a conveyor, in this case a conveyor belt 57. The devices 37A-37B-37C shown here are similar to those described in the context of Figure 5. The assembled material mass 58 for the second material layer 19, or a part thereof, is transferred via the conveyor belt 57, here dumped, onto the material mass 28 for the first material layer 17. It goes without saying that on the basis of the device 57 shown here, several of the specific possibilities for the step of depositing particulate particles 20 and binder particles 59 of the second material layer 19.

Preferably, wood chips are deposited on the basis of at least one of the spreading devices, for example spreading device 37B.

By means of one or more of the other spreading devices 37A-37C, particles 59 of the first binder can be deposited on the conveyor belt 58. Preferably, as shown here, a layer of binder particles 59 is deposited first in the direction of travel, then a layer of wood chips. and then again a layer of binder particles 59. It is noted that a device 57 in which the second material mass 58 is assembled on a conveyor belt 58 can also be used for applying the relevant material mass 58, instead of the first material mass to be pressed. 28, on an already preformed substrate that consists essentially of the aforementioned first material layer 17 only.

Figure 8 shows a graph with the density of the plate material of Figures 1 to 4 in ordinates and the thickness in abscissa, where the thickness is expressed in mm, and the density in kg / m3. The thickness 0 mm corresponds to that side of the plate material formed by the first material layer 17, while the thickness 8 mm is located near the surface formed by the second material layer 19.

The graph shows an average density of 830 kg / m2, a peak density P1 near the surface of the first material layer 17 of 1058 kg / m2 and a peak density P2 near the surface of the second material layer 19 of 1033 kg / m2. The graph clearly shows that the panel material in question has the properties of the particularly independent aspect mentioned in the introduction.

The density remains below the level of these peaks between the aforementioned peak densities P1-P2, but remains above the level of 80% of the mean density.

The minimum density is 717 kg / m? and is achieved approximately in half the thickness of the sheet material.

It is clear from figure 8 that a density profile is achieved very similar to that of a standard HDF plate, but in which one of the peak densities P2 is formed in the aforementioned second material layer 19.

The present invention is by no means limited to the embodiments described above, but such plate material and floor panels can be realized according to different variants without departing from the scope of the present invention.

Claims (26)

Conclusions. 1. - Plate material with at least two material layers (17-19), in which a first material layer (17) forms more than half the thickness (T) of the plate material (16) and is mainly built up by means of a first binder glued and pressed wood particles (18), wherein the first binder is thermosetting, characterized in that the second material layer (19) is present on the surface of the aforementioned plate material (16) and is mainly composed of and glued together by means of a second binder. pressed particulate particles (20), wherein the second binder is thermoplastic and / or elastomer. Plate material according to claim 1, characterized in that the aforementioned plate material (16) consists of the aforementioned two material layers (17-19). Board material according to any of the preceding claims, characterized in that the wood particles (18) of said first material layer (17) are wood fibers, and preferably wherein the said first binder is selected from the range of melamine formaldehyde, urea formaldehyde, melamine urea formaldehyde , phenol formaldehyde, phenol-urea formaldehyde, MDI (“methylene diphenyl diisocyanate”), pMDI (“polymeric methylene diphenyl diisocyanate”), thermosetting acrylate resin and a binder obtained by reaction with dextrose. Sheet material according to any of the preceding claims, characterized in that the particulate particles (20) of the aforementioned second material layer (19) are or contain wood chips or wood fibers. Plate material according to any of the preceding claims, characterized in that the particulate particles (20) of the aforementioned second material layer (19) have a particle size of 500 micrometers or more, as expressed with the d50 value measured with laser light diffraction granulometry, at preferably in accordance with ISO 13320 (2009). Sheet material according to any of the preceding claims, characterized in that the aforementioned second binder is thermoplastic and is selected from the range of polyvinyl butyral (PVB), polyvinyl butyrate, polyvinyl chloride (PVC), polyvinyl dichloride (PVdC), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), thermoplastic polyurethane (TPU), thermoplastic aliphatic polyester, such as polylactic acid (PLA), thermoplastic olefin (TPO). Plate material according to any of the preceding claims, characterized in that the aforementioned second binder is elastomer and is selected from the range of synthetic rubber (neoprene), silicone, polyvinyl butyral and natural rubber (polyisoprene). Plate material according to any of the preceding claims, characterized in that the aforementioned second binder contains or consists of polyvinyl butyral, preferably cross-linked polyvinyl butyral. Sheet material according to claim 8, wherein it contains polyvinyl butyral plasticizers. Sheet material according to claims 8 or 9, wherein the polyvinyl butyral is cross-linked by means of one or more cross-linkers, preferably wherein the one or more cross-linkers contain one or more from the series epoxy resin, dialdehydes, phenolic resin, melamine resin. Plate material according to any of the preceding claims, characterized in that the particle-shaped particles (20) were glued with a thermosetting binder before gluing and pressing. Plate material according to claim 11, characterized in that the thermosetting binder with which the particulate particles (20) were glued before gluing and pressing melamine formaldehyde, urea formaldehyde, = melamine urea formaldehyde, phenol formaldehyde, phenol-urea formaldehyde, MDI (methylene diphenyl diisocyanate), pMDI (“polymeric methylene diphenyl diisocyanate”), thermosetting acrylate resin or a binder obtained by reaction with dextrose is or contains, preferably methylene diphenyl diisocyanate or polymeric methylene diphenyl diisocyanate diisocyanate (pMDI) containing a polyol or a polycaprolactam or other flexible chain extender. Plate material according to any of the preceding claims, characterized in that the thickness (T1) of the aforementioned first material layer (17) is at least three times the thickness (T2) of said second material layer (19). Floor panel with a substrate (14) obtained from a plate material (16) according to any one of the preceding claims. Floor panel according to claim 14, characterized in that the floor panel (1) comprises a decorative top layer (15) which is applied to the surface of the aforementioned plate material (16) formed by the aforementioned second material layer (19). Floor panel according to claim 15, characterized in that the above-mentioned decorative top layer (15) comprises a printed paper sheet (21) and a transparent or translucent layer (22) arranged above it. Floor panel according to claim 16, characterized in that said transparent or translucent layer (22) comprises plastic that has been subjected to at least one thermal curing. Floor panel according to claim 17, characterized in that said thermally cured plastic is thermally cured acrylic resin or an unsaturated polyester. Floor panel according to any one of claims 15 to 18, characterized in that said decorative top layer (15) has a relief with structural features which show a depth greater than the thickness of the decorative top layer (15). Floor panel according to claim 19, characterized in that said structural features at least on one or more edges of the floor panel (1) form lower edge areas (25), such as edge areas in the form of a chamfer. 21.- Plate material with at least one material layer, wherein this material layer (19) is mainly composed of particulate particles (20) glued and pressed by means of a binder, the binder being thermoplastic and / or elastomeric. 22.- Decorative covering material with at least one decorative top layer (15) which is applied to the surface of a material layer (19), this material layer (19) consisting mainly of particulate particles (20) glued and pressed by means of a binder wherein the binder is thermoplastic and / or elastomer. Plate material according to claim 21 or 22, characterized in that the aforementioned binder is polyvinly butyral (PVB). Panel material according to any one of claims 21 to 23, characterized in that the aforementioned particulate particles (20) are wood chips or wood fibers. Plate material according to any one of claims 21 to 24, characterized in that the particulate particles (20) were glued with a thermosetting binder before gluing and pressing. Plate material according to claim 25, characterized in that the thermosetting binder with which the particulate particles (20) were glued before gluing and pressing melamine formaldehyde, urea formaldehyde, = melamine urea formaldehyde, phenol formaldehyde, phenol-urea formaldehyde, MDI (methylene diphenyl), pMDI (“polymeric methylene diphenyl diisocyanate”), thermosetting acrylic resin or a binder obtained by reaction with dextrose 1s or contains, preferably methylene diphenyl diisocyanate (MDI) or polymeric methylene diisocyanate (pMDI) containing a polyol or a polycaprolactam or another flexible chain extender.