NL2028334B1

NL2028334B1 - Decorative panel and method for manufacturing of such a decorative panel

Info

Publication number: NL2028334B1
Application number: NL2028334A
Authority: NL
Inventors: Alberic Boucké Eddy
Original assignee: I4F Licensing Nv
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2022-12-12

Abstract

The invention relates to a decorative panel, in particular a floor panel, ceiling panel or wall panel, comprising: a core provided with an upper side and a lower side, a decorative top structure affixed, either directly or indirectly, on said upper side of the core, a first panel edge comprising a first coupling profile, and a second panel edge comprising a second coupling profile being designed to engage interlockingly with said first coupling profile of an adjacent panel, both in horizontal and in vertical direction.

Description

Decorative panel and method for manufacturing of such a decorative panel The invention relates to a decorative panel, in particular a floor panel, ceiling panel or wall panel, comprising: a core provided with an upper side and a lower side, a decorative top structure affixed, either directly or indirectly, on said upper side of the core, a first panel edge comprising a first coupling profile, and a second panel edge comprising a second coupling profile being designed to engage interlockingly with said first coupling profile of an adjacent panel, preferably both in horizontal and in vertical direction.

In the field of decorative floor coverings, decorative panels are known having a MDF (Medium Density Board) or HDF (High Density Board) based core layer on top of which a decorative substrate is attached to provide the panels a desired appearance. A major disadvantage of these known panels is the hygroscopic nature of the core layer, which affects the lifetime and durability of such panels. For this reason, the traditional MDF/HDF based panels are more and more replaced by polyvinyl chloride (PVC) based panels, also provided with a decorative substrate on top. These PVC based panels have the advantage over of being relatively waterproof compared to MDF/HDF based panels. The PVC based panels are typically enriched with chalk (calcium carbonate), acting as inert filler, wherein the applied amount of chalk has been increased in the course of time, in particular to reduce the cost price of the panels. These panels are also referred to as stone- plastic composite (SPC) panels. Typically, these panels comprise a decorative layer covered by a wear layer to protect said decorative layer and to lengthen the useful life of the floor panel as such. Such wear layers are often composed of transparent polyvinyichloride (PVC) or transparent polyurethane (PU). A top coating may be applied on top of said wear layer to improve the scratch resistance of the floor panel. Although the above decorative floor coverings have advantages, a remaining drawback of various floor panels is that the floor panels are not configured to withstand high local pressures exerted onto the floor panel during normal use, e.g. walking across said floor panels with high-heel shoes, which easily leads to dents (indentations), holes, or other kind of damages. This an inferior indentation and impact resistance may be caused by a relatively thin and/or soft wear layer and/or core layer, which is unable to resist heavy objects or impacts,

and which may easily lead to (micro-)damages, and/or plastic deformation (permanent deformation).

it a first object of the present invention to provide a decorative panel suitable with an improved impact resistance.

it a second object of the present invention to provide a laminated decorative panel comprising an improved decorative top structure with an improved impact resistance.

it a third object of the present invention to provide a laminated decorative panel comprising an improved, polymer based, decorative top structure with an improved impact resistance.

It a fourth object of the present invention to provide a laminated decorative panel comprising improved antimicrobial properties.

At least one of these objects is met by the provision of a decorative panel according to the preamble, wherein the decorative top structure comprises graphene and/or at least one derivative of graphene. lt has been found that by incorporating graphene and/or at least one derivate of graphene in the decorative top structure, the hardness, and hence the indentation and impact resistance of the top structure, and hence of the decorative panel as such, can be increased significantly.

Graphene is a two dimensional layer of carbon atoms, arranged in the form of a honeycomb lattice. This thin, one atom thick lattice is relatively strong, flexible, light-weight, and easy to process, which makes this material very suitable to be incorporated in a decorative panel according to the invention to improve its impact resistance. Moreover, graphene also exhibits excellent heat and electricity conducting properties, which beneficial properties may also be used to further improve the decorative panel according to the invention, as will be elucidated below in more detail. Moreover, graphene and/or derivatives of graphene display excellent anti-oxidant and scratch-resistant properties. Furthermore, it was found that the graphene and/or derivatives of graphene exhibit(s) excellent antimicrobial properties, which fulfils the need to improve existing panels which still have the known benefits while reducing the risk of bacteria growth on and/or in between said panels, in order to expand the applicability of the panels. The most commonly known of graphene derivates are graphene oxide and reduced graphene oxide. Graphene oxide (GO) is a single-atomic layered material, made by the powerful oxidation of graphite, which is relatively cheap and abundantly available. Graphene oxide is an oxidized (and cheaper) form of graphene, laced with oxygen-containing groups. Reduced graphene oxide (RGO) is the form of GO that is processed by chemical, thermal and other methods in order to reduce the oxygen content, while graphite oxide is a material produced by oxidation of graphite which leads to increased interlayer spacing and functionalization of the basal planes of graphite. As an improved hardness is typically desired across the full upper side of the decorative panel, the graphene and/or graphene derivate(s) preferably covers the substantially entire upper side of the core. This coverage may e.g. be realized by applying a continuous layer, discontinuous layer, overlapping or non-overlapping flakes, of particles composed of graphene and/or at least one graphene derivate.

Preferably, the decorative top structure comprises at least two layers of which at least one layer, preferably a substantially transparent or translucent top layer of said top structure, comprises graphene and/or at least one derivative from graphene. The top layer may entirely be composed of graphene and/or at least one derivative from graphene, although it is also imaginable that the top layer comprises a top coating, such as a (hardened or hardenable) lacquer layer or resin layer, wherein the graphene and/or at least one derivative from graphene is/are dispersed and/or at least partially embedded. It is imaginable that the top surface of the decorative top structure is at least partially made from graphene and/or at least one derivative from graphene. It is imaginable that the decorative top structure comprises at least one layer composed of graphene and/or at least one derivative of graphene. Said graphene (derivative) layer can, for example, be a continuous layer or a discontinuous layer or lattice enclosing or provided with one or more fractures. Said at least one layer composed of graphene and/or at least one derivative of graphene may at least partially be enclosed by and/or situated in between two layers of the panel, preferably between two layers of the decorative top structure, such as, for example, the core and a top coating, and/or, a decorative layer and a top coating, and/or the core and a decorative layer, and/or a primer layer and a decorative layer. It is imaginable that the panel, in particular the top structure and/or the core, comprises a plurality of layers, wherein each layer is at least partially composed of graphene and/or at least one graphene derivative. As addressed above, it is imaginable that at least one layer composed of graphene and/or at least one derivative of graphene is at least partially embedded in at least one other layer of the decorative top structure. This latter layer may also be referred to as matrix layer, which is typically composed of a polymer, such as a PVC or PU, comprising substance. This matrix layer typically substantially entirely encloses the layer composed of graphene and/or at least one derivative of graphene, and may penetrate the layer composed of graphene and/or at least one derivative of graphene, in particular — if applied — fractures (fracture openings) are present in the layer composed of graphene and/or at least one derivative of graphene. Preferably, the thickness of said graphene (derivate(s)) embedded layer is between 0.1nm and 60um, more preferably between 0.1nm and 50 um, such as between 0.1 and 1um, more preferably such as between 0.2nm and 0.4nm. Such a layer can be prefabricated and adhered, typically by gluing and/or fusing, to another panel layer during production of the panel. In case such a layer is produced in-line during the panel production process, it is imaginable that the layer thickness exceeds 50um.

It is conceivable that the decorative top structure comprises particles, preferably platelets, such as nanoplatelets, and/or flakes and/or nanoribbons and/or fibres, composed of graphene and/or at least one derivative from graphene. These particles can be randomly distributed in the top structure, although it is commonly preferred to embed said particles in at least one layer of the decorative top structure, preferably at least one polymer layer of the decorative top structure.

Preferably, at least a fraction of said particles overlap at least partially, at least as seen from a top view of the panel. It may be preferred to apply elongated and/or circular particles, wherein at least a fraction of said elongated particles overlap at least partially, wherein, more preferably, said overlapping particles have a likewise orientation. In case said particles are incorporated and/or embedded within an extruded polymer based layer, elongated or circular particles may be orientated in substantially the same direction during extrusion of said polymer based layer.

This particle orientation will typically be substantially parallel to the extrusion direction, or at least closer to parallel to the extrusion direction than to perpendicular to the extrusion direction, during production of said layer.

In this manner a shingle-like 5 structure of graphene (derivate) based particles can be realized, which is in favour of the hardness and impact resistance of the top structure.

The decorative top structure preferably comprises at least one decorative visual print, more preferably a digital decorative print.

This print may be applied directly onto the core and/or may be applied on top of a primer layer of the top structure, wherein said primer layer is applied, either directly or indirectly onto the core.

The visual print, also referred to as décor image, may be formed by a wood pattern.

However, it is well thinkable that the décor image represents another kind of pattern, such as, for example, a customized picture and/or a mosaic pattern or tile pattern.

In case of a mosaic pattern or tile pattern, artificial tiles may be depicted which are aesthetically separated by one or more grouts.

In a preferred embodiment, the top structure comprises a textured surface, in particular a textured upper surface (defining a top surface of the panel). This textured surface (relief surface) typically improves the optical and haptic appearance of the decorative layer.

Said textured surface comprises a pattern of recesses (indentations or impressions) and/or projections, wherein said pattern is preferably at least partially realized by means of printing, in particular digital printing (i.e. by means of a digital printing technique). Digital printing is a method of printing from a digital-based image directly to a media.

This digital image can be a decorative image, but also an image representing at least a part of the top structure.

The digital image can either be a 2D or a 3D image.

By digitally (3D) printing the top structure, an infinite degree of freedom of design of the top structure (and the decorative layer) can be obtained, wherein the top structure (and the decorative layer) moreover can be applied in an accurate manner with a high level of detail, which leads to realistic appearances and unique, one-of-a-kind decorative panels.

This result cannot be achieved by means of traditional mechanically impressed covering structures.

As printing device(s), for example, one or more inkjet printers and/or laser printers may be used.

As indicated above,

the substantially transparent or translucent top structure may be partially or entirely digitally printed. To this end, transparent or translucent, either coloured or non- coloured (transparent) ink, may be used. This allows the printed decorative image to remain visible. The printed décor image(s) of the decorative layer(s) may be based on the CMYK colour principle where the white colour is typically provided by the surface of the white base coat (if applied). This is a 4-color setup comprising cyan, magenta, yellow and black. Mixing these together will give a colour space/gamut, which is relatively small. To increase specific colour or the total gamut spot colours may be added. A spot colour may be any colour. One or more additional colours may be applied, such as at least one additional colour selected from the group consisting of: orange, green, blue, red, white, light grey, light magenta, and light cyan. These colours may be used separately or in combinations. The colours are typically mixed and controlled by a combination of software and hardware (print engine/print heads).

Preferably, at least a part of the textured surface of the top structure is aligned in register with at least a part of at least one decor image formed by the decorative print layer, in particular at least one pattern defined by at least one décor image formed by the decorative print layer. By applying an alignment in register, also referred to as embossing in register, a very realistic and/or artistic design and appearance of the panel can be realized. In this manner, for example, a realistic wood nerve pattern can be realized, wherein the decorated printed wood nerves (2D) are in register (in line) with the embossed printed wood nerves (3D). The same effect can, for example, be realized with a stone like design, an animal skin design, etcetera. Also, in case one or more artificial, decorative grout lines are printed, the textured surface may comprise one or more recessed channels directly above said decorative grout lines to realize a realistic appearance of the panel which is practically equal to the surface relief obtained when using real tiles and grouts.

Preferably, the decorative top structure comprises a decorative visual print layer, at least one substantially transparent or translucent wear layer applied on top of said print layer, and at least one substantially transparent of translucent top coating layer applied on top of said at least one wear layer, wherein at least one wear layer and/or at least one top coating layer comprises graphene and/or at least one derivative of graphene. This preferred embodiment implies that the graphene

(derivative(s)) is applied on top of said decorative print layer, and hence is able to contribute to the protection of said decorative print layer.

Preferably, the decorative top structure comprises at least one composite layer,

which composite layer comprises a graphene and/or graphene derivative content between 0.01% and 1.5 % by weight, preferably between 0.5% and 1.0% by weight of the composite layer.

This amount of graphene and/or graphene derivate is often sufficient to significantly increase the hardness and the impact resistance of the panel, while keeping the cost price increase as limited as possible and/or while keeping the top structure sufficiently transparent and/or translucent to secure sufficient visibility of the decorative print layer of the top structure.

The decorative top structure may comprise at least one layer composed of graphene paper.

Graphene paper is typically composed of graphene and/or one or more of its derivatives, such as graphene oxide(s). Graphene paper is preferably at least partially composed of a graphene nano-sheets assembled in a layer-by-layer manner.

Because of the finite size of the graphene sheets, the in-plane tensile load can hardly be continuously transferred through intralayer bonds of the distributed graphene sheets, thus the interlayer crosslink is preferred to assist the tensile load transfer between adjacent layers.

For graphene nanocomposites the intralayer covalent bonds are usually much stronger than interlayer crosslinks.

Typically, for graphene paper, the used starting material is water-dispersed graphene oxide flakes, which is vacuum filtrated to produce free standing foils.

The thickness of these foils is typically in the range of 0.1-150um, preferably 5-120um.

Like graphene, graphene paper is an electrical conductor, and like graphene oxide, graphene oxide paper is an electrical insulator.

By graphene — graphene oxide paper, the paper is partially composed of graphene, and partially composed of graphene oxide, optionally reduced graphene oxide.

By adjusting the ratio between graphene and graphene oxide, the electrical conductivity of the paper can be tuned.

This may be used to optimize the conductive properties for the aimed application of the decorative panel according to the invention.

It is imaginable that the decorative top structure comprises at least one decorative print layer which is positioned above said graphene (oxide) comprising paper, and wherein said graphene (oxide) comprising paper preferably bears said decorative print layer.

Preferably, the Young's modulus of the decorative top structure is between 9-181 GPa, preferably between 9 and 50 GPa, more in particular approximately 10 GPa. The actual Young's modulus strongly depends on the amount of graphene and/or graphene oxide used, as well as on in which form said graphene and/or graphene is applied. Typically, graphene sheets as such may have a Young's modulus of 1,000 GPa. When graphene is used a part of a composite material in a layer of the top structure, which is often the case, the Young's modulus will typically drop below 181 GPa, and will mostly be around 10 GPa.

Preferably, at least one substantially transparent or translucent layer of the decorative top structure is a printed layer. This layer may or may not comprise graphene and/or graphene derivative(s). It is imaginable that the entire top structure is applied by means of digital printing. It is also imaginable that a part of the top structure, including at least one decorative layer, and at least one wear layer, is applied by means of digital printing.

At least a part of the core may be a thermally insulating (dielectric) and/or at least a part of the core may be thermally conductive. At least a part of the core may be foamed. At least a part of the core may be solid (non-foamed). The core may be flexible, semi-rigid or substantially rigid. The core may comprise at least one polymer selected from the group consisting of: ethylene vinyl acetate (EVA), polyurethane (PU), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinylchloride (PVC), polyethylene terephthalate (PET), polyisocyanurate (PIR), or mixtures thereof. The core may comprise wood and/or at least one wood-based material. The core may comprise at least one composite material of at least one polymeric material and at least one non-polymeric material. The at least one non- polymeric material is preferably selected from the group consisting of: talc, chalk, wood, calcium carbonate, and a mineral filler. The core may comprise magnesium oxide and/or magnesium hydroxide. The upper side of the core is preferably substantially flat. The core may comprise graphene and/or at least one derivative of graphene, more in particular wherein the core comprises at least one layer which is at least partially composed of graphene and/or at least one derivative of graphene. The core may comprises at least one reinforcement layer. At least one reinforcement layer may be formed by a graphene and/or graphene oxide based layer. lt may be preferred that a centreline divides the core into an upper section and a lower section, wherein at least one layer at least partially composed of graphene and/or at least one derivative of graphene is (eccentrically) situated in the upper section and/or lower section of the core.

Optionally, graphene and/or at least one derivative of graphene is merely present in the core, while the top structure is free of any graphene and/or at least one derivative of graphene.

Preferably, the panel is provided with a thermal reflective layer between the core and the decorative top structure.

This feature provides the panel leads to less heat absorption (and dissipation) by the panel, which facilitates the surrounding (indoor) atmosphere to be kept at a desired temperature.

It is imaginable that the decorative top structure comprises at least one conductive layer at least partially composed of graphene and/or at least derivative of graphene, wherein said conductive layer defines a part of opposing side edges of the panel.

This means that the edge(s) of the conductive layer is/are exposed (when considering a panel in non-locked condition). In interlocked condition of adjacent panels, the conductive layers of adjacent panels are preferably interconnected allowing transfer of electrical and/or thermal energy between said panels.

These interconnected conductive layers of different panels facilitate transmission of thermal and/or electrical energy between panels.

This property can be used in various manners.

For example, the facilitated transmission of thermal energy can be used to dissipate thermal energy present in a (warm) panel towards one or more other (cooler) panels.

This phenomenon can also e.g. be used to use the panels as heating source, in particular flooring heating or wall heating, to heat a room.

The facilitated transmission of electrical charge (electrical energy) can be used, for example, to realize an antistatic decorative covering consisting of a plurality of interlocked decorative panels according to the invention.

In this manner (excessive) static electricity, present/generated in a panel, can easily be dissipated to other panels.

Optionally, each panel has a ground connection connecting the conductive layer to a lower side of the panel to facilitate grounding (earthing) of the panel.

This electrical connection between the conductive layer may also be used as electrical heating layer to allow the panels to act as heating panels, such as floor heating panels or wall heating panels.

it has been found that graphene and graphene derivates, like graphene oxide, and reduced graphene oxide, in the following section referred to as graphene materials ("GMs") also exhibit excellent antibacterial and antiviral properties due to their nanomaterial-triggered biosensing action and direct interaction with various cell types and statuses such as bacteria, fungi, and tumoral/normal mammalian cells.

Interestingly, the interaction between bacteria and GMs reveals bacteria’s ability to reduce graphene due to the bacteria’s interaction with graphene oxide, which reduces the bacteria’s oxygen-containing functional groups by glycolysis interaction. In this way, bacteria seem to be passively killing themselves while reducing graphene oxide. The antimicrobial effect of the GMs in the panel according to the invention may be improved by enriching the GM(s) used with at least one of the following additives, in particular metals and/or metal oxides.

Silver nanoparticles (AgNPs) are well known for their broad-spectrum antimicrobial activity, and many studies have demonstrated their antibacterial efficacy against a variety of bacterial strains including E. coli, S. aureus, methicillin-resistant S. aureus (MRSA), and methicillin-resistant Staphylococcus epidermidis. By conjugating AgNPs to graphene oxide sheets, e.g. by using diallyl-dimethyl- ammonium chloride (PDDA), a significantly increased antibacterial activity in comparison to AgNPs alone can be obtained. Polyethyleneimine (PEI) is another linker material that can be used in this respect, and which leads to a GO-PEI- AgNPs hybrid complex with antibacterial activity based on the blade-like edge which is characterized by long-term antibacterial activity and excellent stability and, consequently, causes bacterial cell destruction. Also, conjugated AgNPs to sodium 1-naphthalenesulfonate (NA) functionalized reduced graphene oxide (NArGO) may be used; the resulting AgNP-NArGO nanostructure hybrid demonstrate extensive antibacterial capability, tremendous stability, and minor cytotoxicity. These conjugation approaches show significant enhancement in the antimicrobial activity by merging two potent antimicrobial materials. Furthermore, zinc oxide (ZnO) may be used to be conjugated to graphene oxide (nanoparticles), which also manifest high bactericidal activity against E. coli as well as low cytotoxic effects toward Hela cells in different concentrations. Alternatively,

poly-I-lysine (PLL) reduced graphene oxide, enriched with copper (nano)particles also demonstrates a long-term additively antibacterial impact against Gram- negative E. coli and Gram-positive S. aureus in which practically all bacteria were killed.

Also, a nanocomposite system consisting of reduced graphene oxide and iron oxide nanoparticles (rGO-IONPs) demonstrates a noticeable reduction in bacterial cell viability both in vitro and in vivo.

Furthermore, it was found that a graphene oxide surface doped with iron oxide and silver nanoparticles displays a high antibacterial activity against E. coli and S. aureus.

Generally, the involved antibacterial mechanism is based on physical pressure, oxidative stress, and reactive oxygen species (ROS) (by-products of normal cell activity) production exerted by the applied nanoparticles.

The antimicrobial effect of GM(s), optionally enriched with one or more metals and/or metal oxide, is more present in case the GM(s) is/are located at the top surface of the panel or close to the top surface of the panel.

In particular in case the top surface of the panel is textured, rather than smooth, these antimicrobial properties are favourable as microbes are inclined to grow and develop within recesses of the textured surface, since these recesses are commonly untouched during normal use (e.g. when walking across said panel), and since these recesses may contain water (in case the panel is applied as floor panel). In a preferred embodiment, the first coupling profile and the second coupling profile are preferably configured such that two of such panels can be coupled to each other by means of a lowering movement (fold-down movement). Preferably, the first coupling profile comprises: . an upward tongue, . at least one upward flank lying at a distance from the upward tongue, . an upward groove formed in between the upward tongue and the upward flank wherein the upward groove is adapted to receive at least a part of a downward tongue of a second coupling profile of an adjacent panel, and . optionally, at least one first locking element, preferably provided at a distant side of the upward tongue facing away from the upward flank, and wherein the second coupling profile preferably comprises: . a first downward tongue,

. at least one first downward flank lying at a distance from the downward tongue, . a first downward groove formed in between the downward tongue and the downward flank, wherein the downward groove is adapted to receive at least a part of an upward tongue of a first coupling profile of an adjacent panel, and . optionally, at least one second locking element adapted for co-action with a first locking element of an adjacent panel, said second locking element preferably being provided at the downward flank.

Preferably, the first locking element comprises a bulge and/or a recess, and wherein the second locking element comprises a bulge and/or a recess. The bulge is commonly adapted to be at least partially received in the recess of an adjacent coupled panel for the purpose of realizing a locked coupling, preferably a vertically locked coupling. It is also conceivable that the first locking element and the second locking are not formed by a bulge-recess combination, but by another combination of co-acting profiled surfaces and/or high-friction contact surfaces.

It is imaginable that the first coupling profile and the second coupling profile are configured such that in coupled condition a pretension is existing, which forces coupled panels at the respective edges towards each other, wherein this preferably is performed by applying overlapping contours of the first coupling profile and the second coupling profile, in particular overlapping contours of downward tongue and the upward groove and/or overlapping contours of the upward tongue and the downward groove, and wherein the first coupling profile and the second coupling profile are configured such that the two of such panels can be coupled to each other by means of a fold-down movement and/or a vertical movement, such that, in coupled condition, wherein, in coupled condition, at least a part of the downward tongue of the second coupling profile is inserted in the upward groove of the first coupling profile, such that the downward tongue is clamped by the first coupling profile and/or the upward tongue is clamped by the second coupling profile.

A side of the upward tongue facing towards the core may be at least partly inclined towards the core or the upward flank and a side of the downward tongue facing towards the core may be at least partly inclined towards the core or the downward flank, wherein the locking portions may be formed by said inclined parts, wherein,

in particular, said sides of the tongues and the plane of the panel enclose an angle between 90 and 10 degrees. The inclination of the sides of the tongues towards the respective grooves results in the formation of so-called closed grooves. A closed groove means that the minimal width of the groove is smaller than the maximal width of the tongue, and that deformation of at least one of the coupling parts needs to occur in order to push the tongue into the groove. Alternatively, a side of the upward tongue facing towards the core may be at least partly inclined away from the core or the upward flank and a side of the downward tongue facing towards the core may be at least partly inclined away from the core or the downward flank, wherein, in particular, said sides of the tongues and the plane of the panel enclose an angle between 90 and 110 degrees. The inclination of the sides of the tongues towards the respective grooves results in the formation of so- called open grooves.

In case the panel is rectangular, then the first panel edge and second panel edge are typically situated at opposite short edges of the panel. The panel preferably also comprises at least one third coupling profile and at least one fourth coupling profile located respectively at a third panel edge and a fourth panel edge, wherein the third coupling profile comprises: a sideward tongue extending in a direction substantially parallel to the upper side of the core, at least one second downward flank lying at a distance from the sideward tongue, and a second downward groove formed between the sideward tongue and the second downward flank, wherein the fourth coupling profile comprises: a third groove configured for accommodating at least a part of the sideward tongue of the third coupling profile of an adjacent panel, said third groove being defined by an upper lip and a lower lip, wherein said lower lip is provided with an upward locking element, wherein the third coupling profile and the fourth coupling profile are configured such that two of such panels can be coupled to each other by means of a turning movement (angling down movement), wherein, in coupled condition: at least a part of the sideward tongue of a first panel is inserted into the third groove of an adjacent, second panel, and wherein at least a part of the upward locking element of said second panel is inserted into the second downward groove of said first panel.

Alternative, more intricate coupling profiles are also envisaged, such as coupling profiles which interlink by an angling movement of two side edges of neighbouring panels, or even by a vertical ‘drop-down’ movement of one side edge of panel towards the other side edge of a neighbouring panel. These type of coupling profiles have the additional advantage that the side edges once connected, achieve an interlocking of the profiles in horizontal direction. Preferably, at least a part of at least one coupling profile, preferably each coupling profile, is integrally made from material of the support panel.

The panel according to the invention is typically rectangular, square, of hexagonal, although other shapes are also imaginable. The panel according to the invention can be used indoor, but may also be used outdoor.

As mentioned above, by incorporating graphene and/or at least one derivate of graphene in the decorative top structure, the hardness, and hence the indentation and impact resistance of the top structure, and hence of the decorative panel as such, can be increased significantly. Preferably, the residual indentation of the panel according to the invention is lower than 0.15 mm, more preferably lower than

0.10 mm, most preferably lower than 0.05 mm, when tested in accordance with EN ISO 24343-1. Preferably, the impact resistance of the panel according to the invention is larger than 1800 mm, preferably larger than 2000 mm, when tested in accordance with EN 16511. When tested the micro-scratch resistance in accordance with EN 16094, the panel according to the invention, the gloss change of a micro-scratched panel compared to an unscratched panel is preferably less than 30%, more preferably less than 10% (MSR-A1). When tested the micro- scratch resistance in accordance with EN 16094, the panel according to the invention, preferably no visible scratches are present on the panel (MSR-B1).

The invention also relates to a decorative covering, in particular a floor covering, ceiling covering, or wall covering, consisting of a plurality of interlocked panels according to the invention.

The invention also relates to a method for manufacturing of a decorative panel according to the invention, comprising the steps: a) providing a core;

b) creating and affixing, either directly or indirectly, a decorative top structure on said upper side of the core, wherein the decorative top structure comprises graphene and/or at least one derivative of graphene; and c) providing the first panel edge with the first coupling profile, and the second panel edge with the second coupling profile being designed to engage interlockingly with said first coupling profile of an adjacent panel, both in horizontal and in vertical direction. Preferably, the top structure comprises a plurality of layers, including at least one graphene and/or graphene derivative based layer, wherein during step b) at least one graphene and/or graphene derivative based layer is applied by means of chemical vapor deposition and/or by using a graphene suspension and/or derivative of graphene suspension. It is also imaginable that during step b) at least one graphene and/or graphene derivative based layer is applied by transferring at least one graphene and/or graphene derivative based layer from a transfer foil onto another panel layer, and/or is (digitally) printed onto another panel layer. The transfer foil may or may not be removed after application graphene and/or graphene derivative based layer onto said other panel layer. Hence, the transfer foil can be either a temporary carrier of the graphene and/or graphene derivative based layer or can become integral part of the top structure of the panel. The top structure may comprise a plurality of layers, including at least one graphene and/or graphene derivative based layer, wherein during step b) at least one graphene and/or graphene derivative based layer is electrochemically deposited onto another panel layer, in particular onto a textured upper surface of another panel layer.

The invention will be further elucidated according to the following non-limitative figures: - Figure 1 shows a perspective view of an embodiment of a decorative panel according to the invention; and - Figure 2 shows a schematic transversal cross-section along line B-B of an embodiment of a decorative panel according to the invention, wherein the decorative top structure comprises a substantially homogeneous mixed material; and - Figure 3 shows a schematic transversal cross-section along line A-A of an embodiment of a decorative panel according to the invention, showing another embodiment of a decorative top structure wherein the decorative top structure is a laminated structure; and - Figure 4 shows a transversal cross-section of an embodiment of a decorative panel covering according to the invention.

Figure 1 shows a perspective view of an embodiment of a decorative panel 1 according to the present invention. The panel is of a rectangular shape having a length extending longitudinally along line B-B, and a width extending transversally along line A-A. The panel 1 is provided with a core 2 provided with an upper side and a lower side. The panel is provided with a decorative top structure 12 affixed, either directly or indirectly, on said upper side of the core 2. The sides of the decorative panel 1 are provided with coupling profiles 5,6,7,8. At opposite edges 9,10 a first panel edge 3 comprising a first coupling profile 5, and a second panel edge 4 comprising a second coupling profile 6. The coupling profiles are designed such that the second coupling profile 6 engage interlockingly with said first coupling profile 5 of an adjacent panel, both in horizontal and in vertical direction. The panel 1 is further provided with a third coupling profile 7 and fourth coupling profile 8 at opposite edges 9 and 10 respectively, which also interlockingly engage. Said decorative top structure 12 comprises graphene and/or at least one derivative of graphene. Here, graphene is defined as a single carbon layer of the graphite structure, which monolayer is composed of sp2-hybridized carbon atoms bonded to each other, typically with a 0.142 nm length bond, and tightly packed into a honeycomb lattice, forming a two-dimensional crystal. The monolayer may extend over and cover the entire upper side of the core and/or may be formed by flakes or platelets or other particle-like structures. A suitable graphene derivative is graphene oxide (GO), which is the oxidized derivative of a graphene molecule, obtained by acid oxidation of graphite, resulting in a molecular structure containing oxygen functional groups (such as e.g. hydroxyl, carboxyl, carbonyl, and epoxy). Another suitable graphene derivate is reduced graphene oxide (rGO), which is a graphene derivative obtained through chemical or thermal reduction of GO, i.e., the reduction of the oxygen functional groups in GO. rGO is characterized by its moderately reduced number of functional groups, a high number of electroactive sites, and its structural similarity to graphene. Preferably, the top surface of the decorative top structure 12 is at least partially made from graphene and/or at least one derivative from graphene. Examples thereof are shown and described in figure 2 and 3.

Figure 2 shows a transversal cross-section of an embodiment of a decorative panel 1 according to the present invention, provided with a core 2, a decorative top structure 12 and coupling profiles 7,8. The decorative top structure 12 is directly or indirectly affixed to the upper side 2a of the core 2. For example, the top structure 12 may be glued, by means of an adhesive, and/or fused onto the core 2. The upper side 2a of the core 2 may be substantially flat or may have a textured surface for example when the core comprises a foam material. The lower side of the core 2b may be the lower side of the panel, or may be affixed to a (not shown) base layer. In this embodiment, the top structure 12 is schematically shown as a substantially homogeneous mixed material, for example comprising graphene in the form of particles such as nanoplatelets mixed with a polymer. The decorative top structure 12 may comprise a laminated structure as shown in figure 3.

Fig. 3 shows in transversal cross-section the first coupling part 5 at side edge 3 and the second coupling part 6 at opposing side edge 4. The first coupling part 5 comprises a sideward tongue 20 and the second coupling part 6 comprises a recess 30 for accommodating at least a part of the sideward tongue 20 of a further panel. The recess 30 is configured to actively co-act with a sideward tongue 20 of another panel, in a coupled condition of such panels.

The figure also shows a laminated panel 1 which comprises a core 2, and a graphene and/or derivative of graphene comprising decorative top structure 12 affixed, either directly or indirectly, on the upper side 2a of the core 2. The core 2 comprises preferably an insulating material and/or the panel 1 may further be provided with a thermal reflective layer 15 between the upper side 2a of the core 2 and the decorative top structure 12.

In the shown embodiment, the laminated decorative top structure 12 comprises multiple layers 12a,12b, wherein at least one of the layers comprises graphene and/or at least one derivative of graphene. Several non-limitative embodiments of these layers will be further described below.

In a first embodiment, layer 12a is a substantially transparent or translucent top layer, which comprises graphene and/or at least one derivative from graphene. in this embodiment wherein 12a is a transparent or translucent layer comprising graphene and/or at least one derivative of graphene, layer 12b may comprise a decorative layer comprising a decorative visual print, in particular a thermoplastic or paper film carrying a, preferably digitally printed, decorative image. The graphene comprising top layer 12a serves as a protective layer, such as a finishing layer, and/or a wear layer, positioned on top of said decorative layer. In a second embodiment, the layer 12a is a transparent or translucent finishing layer and layer 12b comprises graphene and/or at least one derivative from graphene for providing the desired mechanical properties to the panel such as scratch-resistance or indentation resistance.

Any of the layers 12a, 12b may also be one composite layer, which composite layer comprises a graphene and/or graphene derivative content between 0.01% and

1.5% by weight, preferably between 0.5% and 1.0% by weight of the composite layer. It is also possible that the layers 12a and 12b together form one composite material, such as shown in figure 2.

Either of the layers 12a, 12b may have a composition wherein the layer comprises patticles, preferably nanoplatelets and/or flakes and/or nanoribbons, composed of graphene and/or at least one derivative from graphene. Optionally, said particles are embedded in one or both layers of the decorative top structure, preferably at least one polymer layer of the decorative top structure.

In another embodiment a third layer 12¢ (not shown) is applied on top of the top layer 12a, such that the decorative top structure 12 comprises a decorative visual print layer 12b, at least one substantially transparent or translucent or translucent wear layer applied on top of said print layer 12b, and at least one substantially transparent or translucent of translucent top coating layer 12c (not shown) applied ontop of said at least one wear layer 12a, wherein at least one wear layer and/or at least one top coating layer comprises graphene and/or at least one derivative of graphene.

Figure 4 shows a decorative covering 31 consisting of a plurality of interlocked panels according to the invention. The figure shows how the coupling profiles 7 and

8 can be coupled to each other when connecting a panel 1 and a panel 1’ to each other. The panel 1’ is hereby moved vertically downwards along the arrow, wherein the profiles 7 and 8 engage with each other by receiving upward tongue 71 in downward groove 83 and receiving downward tongue 81 in upward groove 73.

Optionally, the decorative top structure 12 of the panels comprise at least one conductive layer 12d, which layer is at least partially composed of graphene and/or at least derivative of graphene, wherein said conductive layer 12d defines a part of opposing side edges 13, 14 of the panel 1, 1’. In this embodiment, the conductive layers of adjacent panels 1, 1’ are interconnected when the panels are in interlocked condition, the allowing transfer of electrical and/or thermal energy between said panels 1, 1’.

The coupling profiles shown in the figures serve as an example, any other coupling profiles for interlocking adjacent panels according to the invention may be incorporated.

The above-described inventive concepts are illustrated by several illustrative embodiments. It is conceivable that individual inventive concepts may be applied without, in so doing, also applying other details of the described example. It is not necessary to elaborate on examples of all conceivable combinations of the above- described inventive concepts, as a person skilled in the art will understand numerous inventive concepts can be (re)combined in order to arrive at a specific application.

The ordinal numbers used in this document, like “first”, “second”, “third”, and “fourth” are used only for identification purposes. Hence, the use e.g. of the expressions “third locking element” and “second locking element” does therefore not necessarily require the co-presence of a “first locking element”. The decorative panels according to the invention may also be referred to as decorative tiles. By "complementary" coupling profiles is meant that these coupling profiles can cooperate with each other. However, to this end, the complementary coupling profiles do not necessarily have to have complementary forms. By locking in “vertical direction" is meant locking in a direction perpendicular to the plane of the panel. By locking in "horizontal direction" is meant locking in a direction perpendicular to the respective coupled edges of two panels and parallel to or falling together with the plane defined by the panels. it will be apparent that the invention is not limited to the working examples shown and described herein, but that numerous variants are possible within the scope of the attached claims that will be obvious to a person skilled in the art.

The verb “comprise” and conjugations thereof used in this patent publication are understood to mean not only “comprise”, but are also understood to mean the phrases “contain”, “substantially consist of”, “formed by” and conjugations thereof.

Claims

Conclusions

1. Decorative panel, in particular a floor, ceiling or wall panel, comprising: - a core provided with a top and bottom, - a decorative top structure, whether or not directly attached to the top of the core, - a first panel edge comprising a first joint profile, and a second panel edge comprising a second joint profile designed to engage integrally with the first joint profile of an adjacent panel, both horizontally and vertically, the top decorative structure being graphene and/or at least one derivative of graphene.

The panel of claim 1, wherein the decorative top structure comprises at least one derivative of graphene selected from the group consisting of: graphene oxide and reduced graphene oxide.

A panel according to any one of the preceding claims, wherein the decorative top structure comprises at least two layers, of which at least one layer, preferably a substantially transparent or translucent top layer, comprises graphene and/or at least one derivative of graphene.

A panel according to any one of the preceding claims, wherein the top surface of the decorative top structure is at least partly made of graphene and/or at least one derivative of graphene.

A panel according to any one of the preceding claims, wherein the decorative top structure comprises at least one layer composed of graphene and/or at least one derivative of graphene.

A panel according to claim 5, wherein at least one layer composed of graphene and/or at least one derivative of graphene is at least partially enclosed by two layers of the panel, preferably between two layers of the decorative top structure.

A panel according to claim 5 or 6, wherein at least one layer composed of graphene and/or at least one derivative of graphene is at least partially embedded in at least one other layer of the decorative top structure.

A panel according to any one of the preceding claims, wherein the decorative top structure comprises particles, preferably nanoplatelets and/or flakes and/or nanoribbons, composed of graphene and/or at least one derivative of graphene.

A panel according to claim 8, wherein the particles are embedded in at least one layer of the decorative top structure, preferably at least one polymer layer of the decorative top structure.

A panel according to any one of the preceding claims, wherein the decorative top structure comprises a decorative visual print.

A panel as claimed in any preceding claim wherein the decorative top structure comprises a decorative visual print layer, an at least partially transparent or translucent wear layer disposed on top of the print layer, and at least one substantially transparent or translucent overcoat layer disposed on top of the at least one wear layer, wherein at least at least one wear layer and/or at least one overcoat layer comprises graphene and/or at least one derivative of graphene.

12. Panel according to one of the preceding claims, wherein the decorative top structure comprises at least one composite layer, which composite layer comprises a content of graphene and/or a derivative of graphene between 0.01 wt.% and 1.5 wt.%, at preferably between 0.5 wt.% and 1.0 wt.%.

A panel according to any one of the preceding claims, wherein the decorative top structure comprises at least one layer composed of graphene and/or a derivative of graphene, the thickness of the layer being between 0.1 nm and 1 nm, preferably between 0.2nm and 0.4nm.

A panel according to any one of the preceding claims, wherein the decorative top structure comprises graphene paper.

A panel according to claim 14, wherein the decorative top structure comprises at least one decorative printing layer positioned above the paper comprising graphene, and wherein the paper comprising graphene preferably carries the decorative printing layer.

A panel according to any one of the preceding claims, wherein the Young's modulus of the decorative top structure is between 9 and 11 GPa, preferably about 10 GPa.

A panel according to any preceding claim, wherein at least one substantially transparent or translucent layer of the decorative top structure is a printed layer.

A panel according to any one of the preceding claims, wherein the decorative top structure comprises at least one layer having a textured top surface.

A panel according to any one of the preceding claims, wherein the core is an insulating core.

A panel according to any one of the preceding claims, wherein the core comprises a foam material.

A panel according to any one of the preceding claims, wherein the core is at least partially composed of a dielectric material.

A panel according to any one of the preceding claims, wherein the core comprises graphene and/or at least one derivative of graphene, and in particular wherein the core comprises at least one layer at least partially composed of graphene and/or at least one derivative of graphene.

A panel according to claim 22, wherein a center line divides the core into an upper section and a lower section, with at least one layer composed at least in part of graphene and/or at least one derivative of graphene being present in the upper section and/or lower section of the core.

A panel according to any one of the preceding claims, wherein the panel is provided with a thermal reflection layer between the core and the decorative top structure.

A panel according to any preceding claim, wherein the decorative top structure comprises at least one conductive layer composed at least in part of graphene and/or at least one derivative of graphene, the conductive layer defining a portion of opposing side edges of the panel.

A panel according to claim 25, wherein when adjacent panels are enclosed, the conductive layers of adjacent panels are bonded together allowing the transfer of electrical and/or thermal energy between the panels.

A panel according to any one of the preceding claims, wherein at least one metal or metal oxide is attached to graphene and/or at least one derivative of graphene.

A decorative covering comprising a plurality of enclosed panels according to any one of the preceding claims.

A method of manufacturing a decorative panel according to any one of claims 1 to 27, comprising the steps of: a) providing a core; b) creating and attaching, directly or indirectly, a decorative top structure to the top of the core, wherein the decorative top structure comprises graphene and/or at least one derivative of graphene; and c) providing the first panel edge with the first joining profile, and the second panel edge with the second joining profile, which is designed to engage snugly with the first joining profile of an adjacent panel, both horizontally and vertically.

A method according to claim 29, wherein the top structure comprises a plurality of layers, including at least one layer based on graphene and/or a derivative of graphene, wherein during step b) at least one layer based on graphene and/or a derivative of graphene is applied by chemical vapor deposition.

A method according to claim 29 or 30, wherein the top structure comprises a plurality of layers, including at least one layer based on graphene and/or a derivative of graphene, wherein during step b) at least one layer based on graphene and/or a derivative of graphene is applied using a suspension of graphene and/or a suspension of a graphene derivative.

A method according to any one of claims 29-31, wherein the top structure comprises a plurality of layers, including at least one layer based on graphene and/or a derivative of graphene, wherein during step b) at least one layer based on graphene and/or a graphene derivative is applied by transferring at least one layer based on graphene and/or a graphene derivative from a transfer foil onto another panel layer.

A method according to any one of claims 29-32, wherein the top structure comprises a plurality of layers, including at least one layer based on graphene and/or a derivative of graphene, wherein during step b) at least one layer based on graphene and/or a derivative of graphene is printed on another panel layer.

A method according to any one of claims 29-33, wherein the top structure comprises a plurality of layers, including at least one layer based on graphene and/or a derivative of graphene, wherein during step b) at least one layer based on graphene and/or a derivative of graphene is electrochemically deposited on another panel layer, in particular on a textured top surface of another panel layer.