Decorative panel, decorative covering comprising a plurality of said panel, method for manufacturing said decorative panel and method for identifying polymer of said decorative panel

Abstract

The invention relates to a decorative panel, in particular a decorative floor panel, comprising: at least one core layer provided with an upper side and a lower side; and a decorative top structure secured directly or indirectly to the upper side of the core layer wherein the panel, in particular the core layer, consists at least partially of at least one polymer matrix embedded with at least one tracer material readily identifiable by spectroscopy.

Description

Technical Field

[0001] The invention relates to a decorative panel, in particular a decorative floor panel, comprising at least one core layer provided with an upper side and a lower side and a decorative top structure fixed directly or indirectly to the upper side of the core layer. The invention also relates to a decorative covering consisting of a plurality of mutually coupled decorative panels. The invention also relates to a method for producing a decorative panel according to the invention. The invention also relates to a method for identifying a polymer of a decorative panel according to the invention. Background Art

[0002] Since the 1950s, the use and production of plastics has been growing globally at approximately 10% per year. The demand for raw materials to produce such polymers has increased as the demand for plastics has increased. Recycling end-of-life products containing polymer materials is a solution to reuse polymer materials and / or raw materials present in post-consumer products. Decorative panels are frequently used products that contain polymer materials and other recyclable materials. Due to the large number of polymer and additive types, grades and blends present in one panel, it is difficult to recycle different materials, especially polymer materials, in post-consumer decorative panels. In addition, the materials used in each panel are also different. Therefore, it is difficult to recycle decorative panels because it is difficult to identify, separate and sort post-consumer panels based on polymer materials. Summary of the invention

[0003] A first object of the present invention is to provide a decorative panel having more easily recyclable properties.

[0004] A second object of the present invention is to provide a method for identifying and recognizing one or more materials, in particular one or more polymeric materials, used in decorative panels.

[0005] A third object of the present invention is to provide a method of authenticating and identifying one or more panel characteristics associated with a decorative panel, in particular one or more panel characteristics associated with recycling.

[0006] One or both objects may be achieved by providing a panel, in particular a decorative panel, according to the preamble, comprising:

[0007] at least one core layer having an upper side and a lower side;

[0008] a decorative top structure secured directly or indirectly to said upper side of said core layer;

[0009] The panel, in particular the core layer and / or another panel layer, at least partially consists of at least one material, preferably a polymer-containing material, and at least one tracer material, wherein the tracer material is embedded in the material, and / or bonded to the material, and / or arranged in the material, and is preferably a polymer-containing material, wherein the at least one tracer material is easy to identify by spectroscopic methods.

[0010] Preferably, the panel, in particular the core layer and / or another panel layer, consists at least partially of at least one matrix (material), for example at least one polymer matrix and / or a mineral matrix, in which at least one matrix (material) is at least partially embedded with at least one tracer material that is easily identifiable by spectroscopic methods.

[0011] By providing such decorative panels, matrices, in particular polymer matrices and / or mineral matrices, in post-consumer panels can be analyzed, identified and therefore recognized during recycling. The advantage of being able to identify and therefore recognize tracer materials in matrix materials, in particular polymer matrix materials, in decorative panels is that this will facilitate post-use treatment, in particular recycling, of the panels or one or more layers thereof. After the identification of the tracer materials present in the panels, this information and / or information derived therefrom can be used directly or indirectly subsequently to classify and / or separate panels of different composition and / or to classify and / or separate panel layers of panels according to the invention. Thus, panels and / or panel layers rich in tracer materials can, for example, be separated from panels and / or panel layers that do not contain any tracer materials (which are easily identified by spectroscopic methods), and / or different panel layers of panels having mutually different tracer materials (which are easily identified by spectroscopic methods) can be separated from each other. Preferably, different panels based on different matrix materials (e.g. different polymer matrix materials and / or different alternative matrix materials, in particular mineral matrix materials) can be identified as different by using different tracer materials in the different panels. This allows and facilitates post-use processing, such as separation of panels for recycling purposes. It is conceivable that one or more mutually different tracer materials are associated with a group or the same group of materials, which may be useful, for example, to determine that certain (parts) of the panels do not necessarily have to be separated for recycling purposes. It is also conceivable that after the tracer material present in the panel has been identified, this information and / or information derived from it may contain deposit-related information. Information related to the presence of the tracer material can then be used directly or indirectly to determine whether the panel is eligible for a post-use deposit refund once the panel is recollected. The presence of a predetermined tracer material can allow detection of whether a deposit has been paid for the corresponding panel, preferably a prepaid deposit, and whether the deposit can be refunded after the post-use recollection of the panel (e.g. for recycling purposes). After the panel has been identified based on the information associated with the detected tracer material and the deposit and / or (prepaid) deposit value has been identified, for example by (the controller of) the return device, the user may receive a financial refund. Such a deposit refund system incentivizes and promotes the recycling of panels. Such recollection of deposited panels may be performed, for example, at a predetermined recollection location and / or by using a self-service recollection device (return device) which is configured to read the deposit-related information-bearing element and preferably handles at least a part of the deposit refund process.

[0012] The tracer material can be easily identified by atomic spectroscopy, in particular atomic emission spectroscopy (AES) and / or atomic absorption spectroscopy (AAS). AAS quantifies the absorption of electromagnetic radiation by well-separated neutral atoms, while AES measures the radiative emission of excited atoms. The advantage of using atomic spectroscopy is that the technique is able to determine tracer materials embedded in a matrix (e.g., a polymer matrix and / or a mineral matrix and / or a wood matrix). In addition, atomic spectroscopy is an optical sorting method suitable for penetrating a dark polymer matrix layer of a decorative floor panel to identify at least one tracer in the polymer matrix. The tracer material can be measured and identified, for example, by using an atomic absorption spectrophotometer (AAS), proton and / or induced X-ray emission (PIXE) and X-ray fluorescence (XRF). AAS is an analytical method for the qualitative and quantitative determination of chemical elements, particularly in trace element analysis. The process is based on the absorption of radiant energy, usually in the ultraviolet (UV) and visible regions (V) of electromagnetic radiation. The process begins with atomization, a process that breaks down elements into atoms by heat at several thousand degrees but less than 3000°C. When a gaseous solution is employed, both emission and absorption analysis can be performed. At this temperature, only a small fraction of the monatomic particles are excited to a higher electronic state (excited state) which emits radiation and returns to the ground state almost immediately, as its lifetime is only a few nanoseconds. The wavelength of energy released during the excited state is characteristic of each element when it returns to the ground state. At this point, they emit electrons, which is the basis of flame emission photometry. The wavelength and intensity of the emission lines vary for each element. Although AAS can be used to identify tracer materials in paneling, this destructive technique is generally less preferred than non-destructive techniques such as PIXE and XRF.

[0013] PIXE is a powerful but non-destructive technique for determining the elemental composition of a material or sample. When a material is exposed to an ion beam, atomic interactions occur, releasing electromagnetic radiation at wavelengths in the X-ray portion of the electromagnetic spectrum specific to that element. PIXE exploits the emission produced by a material by bombarding the sample with two types of ions at high energy: alpha particles (He ++ ) and protons (H +) in the form of charged particles. These charged particles knock out elements in the innermost electron shell, called the K shell. To fill the void, electrons from the outer shell replace the inner shell electrons with a mantle that absorbs (sponges) the energy emission in the form of X-rays. Each atom has its own unique atomic properties that allow materials to be analyzed using PIXE. One advantage of PIXE is that it can be performed both in and out of a vacuum; therefore, entire samples such as rocks and minerals can be analyzed non-destructively. A diverse range of samples such as solids (plastics, paper or metals), powdered materials (fly ash, activated carbon, catalysts and corrosion products), liquids (oils, process water and solutions) and aerosol filters (thin film samples) are analyzed by PIXE. Advantages of PIXE include high sensitivity, multi-element capability to analyze any element from sodium to uranium in a single spectrum, and a non-destructive proton beam that allows the sample to be preserved after analysis. In a preferred embodiment, at least one tracer material is susceptible to identification by X-ray fluorescence (XRF). The advantage of using XRF is that this technique is able to determine tracer materials, including earth (oxide) metals, embedded in a matrix, especially a polymer matrix, in a relatively rapid manner. In addition, XRF is an optical sorting method that is often suitable for penetrating the dark polymer matrix layer of decorative floor panels to identify at least one tracer in the polymer matrix. Another advantage of XRF is that the identification is fast and volumetric inspection can be performed. The basic principle of XRF is similar to PIXE. When a material is exposed to short wavelength X-rays or gamma rays, it causes ionization of its constituent atoms, which involves the ejection of one or more electrons from the atoms when the atoms are exposed to radiation with an energy greater than their ionization potential. The energy of X-rays and gamma rays is sufficient to eject tightly bound electrons from the inner orbits of the atoms. The ejection of electrons in this way destabilizes the electronic structure of the atoms, and electrons from higher orbits "fall into" lower orbits to fill the holes left behind. When this happens, energy is released in the form of photons, which is equal to the energy difference of the two orbits involved. Therefore, the material emits radiation with the energy characteristics of the atoms present. The term "fluorescence" refers to the phenomenon whereby the absorption of radiation of a specific energy results in the re-emission of radiation of a different (usually lower) energy. As mentioned above, the advantages of XRF include a non-destructive analytical technique, having relatively simple spectral lines, without excessive interferences and can be performed at high speed. In addition, XRF allows multi-element analysis to be completed within a few minutes and has high precision and accuracy, which makes XRF generally the most preferred technique for the specific purpose of tracer material identification in (decorative) panelling. In addition, the cost of XRF equipment is much lower than that of PIXE equipment, which is another reason why XRF is preferred over PIXE. Other possible spectroscopic methods in this regard are optical emission spectroscopy (OES), inductively coupled plasma atomic emission spectrometry (ICP-AES), ICP and neutron activation analysis (gamma spectroscopy).If the decorative panel, in particular the core layer, is at least partially transparent and / or translucent, UV spectroscopy or UV-visible spectrophotometry (UV-Vis or UV / Vis) may be used.

[0014] The tracer material preferably comprises and / or consists of elements having an atomic number equal to or higher than 30. The advantage of using such a tracer material is that these elements can emit sufficient energy after being excited so that this energy is less easily absorbed by dust, air or other inconvenient intervening materials, such as in the decorative floor panel, than elements with an atomic number lower than 30.

[0015] The at least one tracer material may be or may comprise at least one solid metal. The at least one solid metal may be selected from germanium (Ge), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), molybdenum (Mo), iodine (I), lutetium (Lu) and tungsten (W). The advantage of using these solid metals is that these elements show very low toxicity and radioactivity. In addition, in a matrix material such as a mineral and / or polymer-based matrix material, these solid metals are neither additives nor natural tracer materials. Therefore, the solid metals can generally be used to identify the matrix material.

[0016] The at least one tracer material may be or may comprise a rare earth element. The at least one rare earth element may be selected from the group consisting of: yttrium (Y), lanthanum (La), neodymium (Nd), samarium (Sm), gadolinium (Gd), cerium (Ce), praseodymium (Pr), europium (Eu), terbium (Tb), dysprosium (Dy), erbium (Er), holmium (Ho), thulium (Tm) and ytterbium (Yb). The advantage of using these rare earth elements is that these elements show very low toxicity and radioactivity. Furthermore, in a matrix material such as a polymer-based matrix material, these rare earth elements are neither additives nor natural tracer materials. Therefore, the rare earth elements can generally be used to identify a matrix, in particular a polymer matrix, in a decorative panel.

[0017] The at least one tracer material may comprise at least one rare earth oxide, preferably selected from Y 2 O 3 ,La 2 O 3 、CeO 2 , Pr 2 O 3 、Nd 2 O 3 、Sm 2 O 3 、Eu 2 O 3 , Gd 2 O 3 , Tb 2 O3 、Dy 2 O 3 、Ho 2 O 3 , Er 2 O 3 、Tm 2 O 3 and Yb 2 O 3 Alternatively, the at least one tracer material may comprise a rare earth oxide selected from Y 2 O 3 ,La 2 O 3 、Nd 2 O 3 , Gd 2 O 3 、Dy 2 O 3 、CeO 2 , Pr 2 O 3 、Sm 2 O 3 and Yb 2 O 3 Optionally, the at least one tracer material may include a rare earth oxide selected from Y 2 O 3 ,La 2 O 3 , Pr 2 O 3 、Nd 2 O 3 , Gd 2 O 3 、CeO 2 , Pr 2 O 3 、Sm 2 O 3 , Gd 2 O 3 , Er 2 O 3 and Yb 2 O 3 The at least one tracer material may include a rare earth oxide selected from Eu 2 O 3 , Tb 2 O 3 、Dy 2 O 3 、Ho 2 O 3 , Er 2 O 3 and Tm 2 O 3The advantage of using rare earth oxides is that they are the most chemically stable form of rare earth elements.

[0018] The at least one tracer material may comprise monazite and / or bastnasite and / or xenotime and / or may be at least partially derived from monazite and / or bastnasite and / or xenotime. The advantage of using these minerals is that they can extract the rare earth elements present. The tracer weight concentration of the at least one tracer material in the matrix, in particular in the polymer matrix, may be in the range of 0.1 to 1.0 grams of tracer material per kilogram of matrix, in particular per kilogram of polymer matrix, in the core layer and / or any other panel layer; and / or the tracer weight concentration of the at least one tracer material in the matrix, in particular in the polymer matrix, in the core layer and / or any other panel layer may be in the range of 100 to 1000 ppm. The advantage of using such a tracer weight concentration is that it does not affect the properties of the polymer and / or other non-polymer materials used in the matrix and such a concentration is cost-effective.

[0019] As mentioned above, the matrix may at least partially consist of one or more polymers. Preferably, at least one panel layer comprises at least one polymer matrix, which at least one polymer matrix at least partially consists of a polymer selected from polypropylene (PP), polyurethane (PU), thermoplastic polyurethane (TPU), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET) and polyvinyl chloride (PVC).

[0020] As mentioned above, the matrix may at least partially consist of one or more non-polymer materials. The matrix may be free of any synthetic polymers and / or any natural polymers. Preferably, at least one panel layer comprises at least one matrix which at least partially consists of a non-polymer matrix material, and / or a material selected from the following materials may be used as substrate: mineral materials, such as magnesium oxide, magnesium hydroxide, gypsum, (lightweight) concrete and / or clay; and / or wood or wood-based materials, such as HDF or MDF, or any other material free of thermoplastics.

[0021] The panel may be provided with at least one coating and / or impregnating agent, wherein preferably, the coating and / or impregnating agent is provided with a tracer material. It is conceivable that at least one connecting profile (if provided) is impregnated, for example to improve the water resistance of the connecting profile and / or for example to smooth the connection of connecting profiles of adjacent panels. By including one or more tracer materials in the impregnating agent, this can simultaneously be used to associate the panel properties. Alternatively and / or additionally, the panel may comprise at least one coating, and / or a top coating, and / or a paint layer, and / or a wear-resistant layer or the like. It is conceivable that at least one of the layers comprises or is provided with one or more tracer materials, which preferably characterize the layer and / or a polymer or other component present in the layer.

[0022] At least one secondary tracer material may comprise a magnetic material, in particular magnetic particles, and / or partially consist of a magnetic material, in particular magnetic particles, which may, for example, consist of iron and / or cobalt and / or nickel. The magnetic material is preferably selected from magnetite, ferrosilicon and iron metal particles. These magnetic particles may be present in at least one paneling layer in an amount of 0.01% to 5% of the weight of the paneling layer. The magnetic particles are typically embedded in a polymer material (polymer matrix) of the paneling layer. The presence of magnetic particles may further facilitate the post-use separation of different materials of the paneling, preferably after delamination and / or shredding of the layers of the decorative paneling. By applying a magnetic field, the magnetic particles or parts can be separated from the non-magnetic particles or parts. Different paneling layers can be provided with different concentrations of magnetic particles to achieve different levels of enhanced magnetic susceptibility between the layers. More complex magnetic separations can be achieved by subsequently applying magnetic fields with different magnetic field strengths.

[0023] The decorative top structure of the decorative panel may comprise a plurality of layers. The decorative top structure may consist at least partially of a polymer material. The decorative top structure may comprise at least one layer, which may comprise a polymer matrix and at least one tracer material embedded in the polymer matrix.

[0024] The at least one core layer may comprise a polymer matrix and at least one tracer material. The at least one core layer may comprise a polymer matrix having a plurality of polymers. The core layer may also be free of polymer material.

[0025] The at least one first paneling layer may comprise a first matrix (e.g. a first polymer matrix) and at least one first tracer material, wherein at least a second paneling layer may comprise a second matrix (e.g. a second polymer matrix) and at least one second tracer material. The first (polymer) matrix and the second (polymer) matrix may at least partially consist of the same polymer. The first (polymer) matrix and the second (polymer) matrix may at least partially consist of different polymers. The first tracer material and the second tracer material may be the same tracer material. The first tracer material and the second tracer material may be different tracer materials.

[0026] Preferably, each tracer material is assigned to a specific material and / or a specific material combination used in the panel. The specific material can be a polymer or a non-polymer material. The specific material can be the main component of the matrix material used in the panel. However, the specific material can also be a specific additive or alternative material used in the panel. It is also conceivable that a tracer material or a combination of tracer materials is assigned to a (predefined) specific combination of materials. Such a material combination can even form an entire material recipe (ingredient list) present in a combination of one layer or multiple layers. For example, tracer material A can be assigned to a combination of polymer type B with additives C and D. In this case, many variations are conceivable. This enables a specific tracer material (or a combination of tracer materials) to characterize a specific material and / or a specific material combination used in the panel. Here, for example, preferably each polymer type is assigned to its own tracer material or tracer material combination. In this way, the identified tracer material or combination of tracer materials forms a legend that points directly to the polymer used in the panel or at least one panel layer. Thus, preferably the first polymer matrix and the second polymer matrix (if used) may at least partially consist of different polymers, wherein the first tracer material is embedded in the first polymer matrix and the second tracer material different from the first tracer material is embedded in the second polymer matrix.

[0027] As mentioned above, at least one panel layer may contain a plurality of different tracer materials which are easily identifiable by spectroscopy, in particular atomic spectroscopy (eg XRF).

[0028] The at least one tracer material may be embedded substantially uniformly in the polymer matrix. This has the advantage that the tracer material can be identified at any location of the panel. Furthermore, if the panel is cut into pieces, for example during panel installation and / or during post-treatment, the polymer-tracer combination can still be detected for sorting, separation and / or recovery purposes. It is also conceivable that the at least one tracer material is embedded unevenly in the polymer matrix. This makes the production process of the decorative panels, in particular the production process of the panel layers comprising the tracer material, potentially less critical. The latter may result in discontinuous detection of the tracer material in the decorative panel layers, but such discontinuities are generally not critical for the intended purpose.

[0029] Optionally, the tracer material is embedded in the polymer matrix only at at least two, preferably all edges and / or edge regions (edge ​​portions) of the panel and is identified only at these locations. Since at least a portion of the original edge will be present and retained in the cut panel, the panel components can still be identified by the tracer material. This local embedding of the tracer material will save tracer material, which is generally advantageous, at least from an economic point of view. At least a portion of the panel can be provided with at least one coating. Similarly, a portion can be impregnated, wherein the coating and / or the impregnated portion contain at least one tracer material. Optionally, at least one connecting profile is at least partially impregnated and / or coated, wherein the impregnated portion and / or the coated portion can contain the tracer material. Since the connecting profile is usually (visibly) exposed, this area can be easily approached to detect the tracer material, while only a minimum amount of tracer material is required.

[0030] The decorative top structure may comprise at least one decorative layer, preferably a digitally printed decorative layer, and at least one transparent and / or translucent layer at least partially covering said decorative layer.At least a part of the decorative top structure may be releasably fixed to the core layer.

[0031] The panel may comprise at least one backing layer which is directly or indirectly releasably fixed to the underside of the core layer. The core layer and the backing layer may consist at least in part of the same polymer. Alternatively, the core layer and the backing layer may consist of one or more different polymers. The backing layer may also consist of another material, such as cork and / or felt. The at least one backing layer may comprise at least one tracer material, in particular a polymer matrix, wherein the at least one tracer material is embedded in the polymer matrix.

[0032] The at least one polymer matrix may at least partially consist of a polymer, which is formed by a mixture of virgin polymer material and recycled polymer material. The at least one polymer matrix may be enriched with at least one additive, preferably at least one additive selected from the group consisting of talc, chalk, wood, calcium carbonate, titanium dioxide, calcined clay, porcelain, glass particles, glass fibers, carbon particles, silicon particles, (other) mineral fillers, rice, (other) natural fillers, (other) (auxiliary) polymers, such as elastomers and / or latex. Optionally, at least one additive is provided with at least one tracer material. Fillers such as limestone particles may, for example, be coated with a tracer material and / or impregnated with a tracer material. It is also conceivable that rubber and / or elastomer parts (particles) are dispersed in the composite material to increase flexibility and / or impact resistance at least to a certain extent. The core layer may (therefore) be rigid, semi-flexible or flexible, and the floor covering element itself may therefore also be rigid, semi-flexible or flexible. The filler may be formed by fibers, such as glass fibers or synthetic fibers or leather fibers, and / or may be formed by dust-like particles. Here, the term "dust" is understood to mean small dust-like particles (powders), such as bamboo chips, wood chips, cork chips or non-wood chips, such as mineral dust, stone powder, in particular cement, and combinations thereof. The average particle size of the dust is preferably 14 μm to 20 μm, more preferably 16 μm to 18 μm. The main function of this filler is to provide the core layer and the panel itself with sufficient hardness, and / or to reduce the cost price of the core layer and the panel. In addition, this filler will generally also increase the impact strength of the core layer and the panel itself. Preferably, the filler content in the composite material of the core layer is 30% to 75% (weight percentage) of the composite material of the core layer, more preferably 50% to 60% of the composite material of the core layer. Preferably, the polymer content in the composite material of the core layer is 25% to 70% (weight percentage) of the composite material of the core layer, more preferably 40% to 50% of the composite material of the core layer. The polymer can be foamed or non-foamed. Preferably, the composite material of the core layer contains at least one filler selected from salt, stearate, calcium stearate and zinc stearate. Stearates have the function of stabilizers and lead to more favorable processing temperatures and resist decomposition of composite components during and after processing, thereby providing long-term stability. As an alternative or supplement to stearates, calcium zinc, for example, can also be used as a stabilizer. The weight content of the stabilizer in the composite material is preferably 1% to 5%, more preferably 1.5% to 4%. The composite material of the core layer preferably contains at least one impact modifier, which contains at least one alkyl methacrylate, wherein the alkyl methacrylate is preferably selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, tert-butyl methacrylate and isobutyl methacrylate. Impact modifiers generally improve product properties, especially impact resistance.Furthermore, impact modifiers typically toughen the core layer and can therefore also be considered as toughening agents, which further reduces the risk of breakage. Typically, the modifier also facilitates the production process, for example, as described above, in order to control the formation of a foam with a relatively consistent (constant) foam structure. The weight content of impact modifier in the composite material is preferably 1% to 9%, more preferably 3% to 6%. The at least one plastic material used in the core layer preferably does not contain any (toxic) plasticizers, in order to increase the desired rigidity of the core layer, which is also advantageous from an environmental point of view. The core layer and / or a further layer of the panel may comprise a wood-based material, such as MDF, HDF, sawdust, bamboo, prefabricated wood, more particularly so-called engineered wood. Such a wood-based material may be part of the composite material of the core layer.

[0033] It is conceivable that the core layer and / or at least one core layer (and / or another layer) comprises a composite material of at least one polymer and rice. Preferably, the rice is formed from rice husks, more preferably a mixture of separated rice husks and / or ground rice husks and / or rice husk powder. Preferably, different rice husk types have different average particle sizes. Polymers are used as polymer binders, wherein at least partially recycled plastic polymers, such as TPU, PP, PE, PET and / or PVC are preferably used. Unground rice husks can be present, for example, in an amount (weight percentage) of 1% to 98% relative to the weight of the rice husk mixture. Similarly, ground rice husks and powdered rice husks can also be present in an amount (weight percentage) of 1% to 98% relative to the weight of the rice husk mixture. Preferably, in one embodiment, the rice husk mixture contains unground rice husks, ground rice husks and rice husk powder in an amount of 20% to 50% by weight. In a particularly preferred embodiment, the rice husk mixture contains unground rice husks, ground rice husks and rice husk powder in an amount of about 33% by weight. The amount of polymer binder present in the rice husk mixture may vary, for example, from 1% to 30%, preferably from 10% to 25%, more preferably from 12% to 20% by weight of the rice husk mixture. The average particle size of the rice husk powder is preferably from 0.175 mm to 1.20 mm.

[0034] It is conceivable that at least one core layer (and / or at least one other layer) comprises rice husk, rice straw and plant adhesive. Preferably, the plant adhesive comprises weeds and / or wood chips. Preferably, the weeds include any one or more selected from rice straw, glutinous rice grass and starch grass. Preferably, rice straw and / or rice husk are used in an amount of 20% to 50%, preferably 40% to 50%, more preferably 35% to 45% by weight, based on the weight of the (core) layer in which the rice straw and / or rice husk are combined, especially embedded. When the weight percentage exceeds 50% of rice straw, there may be a problem of a significant decrease in moisture resistance, and when the weight percentage is less than 20% of rice straw, the bonding force may decrease. Preferably, the amount of plant adhesive accounts for 1% to 20% (weight percentage) of the (core) layer.

[0035] Rice husks may be added as a main component of the insulation material to provide porosity and thus provide thermal and acoustic insulation. Rice straw may be added to provide a bond with the insulation material. Preferably, the rice straw is cut to a suitable length, preferably 3 cm or less.

[0036] The plant adhesive (plant binder) that can be used in at least one core layer (and / or at least one other layer) preferably uses a tree such as weeds, pine bark, rubber tree, etc. prepared by mixing rice flour such as straw, glutinous rice grass, starch grass, and gluten with water. Preferably, a mixture of weeds and trees is preferably used in terms of improving moisture resistance. When weeds and tree liquid are mixed and used, the mixture is preferably used in a ratio of 2.5:7.5 to 6.5:3.5.

[0037] In a preferred embodiment of the invention, at least one core layer and / or at least one further layer comprises a mixture of clay, in particular kaolin, and rice, in particular rice husks. The clay serves to increase the flash point of the rice, in particular the rice husk, which is advantageous from a fire safety point of view, and the clay also serves to further increase the strength of the core layer (and / or further layer) in which the clay and rice are bound, in particular embedded.

[0038] Preferably, the panel comprises a first panel edge and a second panel edge, preferably opposite to the first panel edge, the first panel edge comprising a first connecting profile, the second panel edge comprising a second connecting profile, the second connecting profile being designed to interlockingly engage with the first connecting profile of an adjacent panel, preferably both in horizontal and vertical direction.

[0039] Preferably, the first coupling profile and the second coupling profile are configured such that two of such panels can be coupled to one another by a rotational movement and / or by a vertical movement.

[0040] It is generally preferred that the panel comprises at least one third coupling profile and at least one fourth coupling profile at the third panel edge and the fourth panel edge, respectively.Preferably, the third coupling profile and the fourth coupling profile are configured such that two of such panels can be coupled to each other by a rotational movement.

[0041] In a preferred embodiment, the first connecting profile and / or the third connecting profile comprises: an upward tongue; at least one upward wing located at a certain distance from the upward tongue; an upward groove formed between the upward tongue and the upward wing, wherein the upward groove is suitable for receiving at least a portion of the downward tongue of the second connecting profile of an adjacent panel; and at least one first locking element, which is preferably arranged on the far side of the upward tongue away from the upward wing, and wherein the second connecting profile and / or the fourth connecting profile comprises: a first downward tongue; at least one first downward wing located at a certain distance from the downward tongue; a first downward groove formed between the downward tongue and the downward wing, wherein the downward groove is suitable for receiving at least a portion of the upward tongue of the first connecting profile of an adjacent panel; and at least one second locking element, which is suitable for cooperating with the first locking element of the adjacent panel, wherein the second locking element is preferably arranged at the downward wing.

[0042] Preferably, the first locking element comprises a projection and / or a recess, and wherein the second locking element comprises a projection and / or a recess. The projection is generally adapted to be at least partially received in a recess of an adjacent coupling panel to achieve a locked coupling, preferably a vertically locked coupling. It is also conceivable that the first locking element and the second locking element are not formed by a projection-recess combination, but by another combination of co-acting profiled surfaces and / or high friction contact surfaces.

[0043] In the above embodiments, it is conceivable that the first connecting profile (and / or the third connecting profile) and the second connecting profile (and / or the fourth connecting profile) are configured so that there is a preload in the connected state, which presses the connecting panels at the corresponding edges towards each other, wherein this is preferably performed by applying overlapping profiles of the first connecting profile (and / or the third connecting profile) and the second connecting profile (and / or the fourth connecting profile), in particular overlapping profiles of downward tongues and upward grooves and / or overlapping profiles of upward tongues and downward grooves, and wherein the first connecting profile (and / or the third connecting profile) and the second connecting profile (and / or the fourth connecting profile) are configured so that two such panels can be connected to each other by a downward folding movement and / or a vertical movement, wherein in the connected state, at least a portion of the downward tongue of the second connecting profile (and / or the fourth connecting profile) is inserted into the upward groove of the first connecting profile (and / or the third connecting profile), so that the downward tongue is clamped by the first connecting profile (and / or the third connecting profile) and / or the upward tongue is clamped by the second connecting profile (and / or the fourth connecting profile).

[0044] It is conceivable that the first coupling contour is designed to cooperate with the second coupling contour and the fourth coupling contour, and the third coupling contour is also designed to cooperate with the second coupling contour and the fourth coupling contour. It is conceivable that the first coupling contour and the fourth coupling contour are identical.

[0045] In an embodiment of the panel according to the present invention, the first connecting profile and / or the third connecting profile comprises: a lateral tongue extending in a direction substantially parallel to the upper side of the core layer; at least one second downward wing located at a certain distance from the lateral tongue; and a second downward groove formed between the lateral tongue and the second downward wing, and wherein the second connecting profile and / or the fourth connecting profile comprises: a third groove, which is configured to accommodate at least a portion of the lateral tongue of the third connecting profile of an adjacent panel, the third groove being defined by an upper lip and a lower lip, wherein the lower lip is provided with an upward locking element, wherein the third connecting profile and the fourth connecting profile are configured so that two such panels can be connected to each other by a rotational movement, wherein in the connected state, at least a portion of the lateral tongue of the first panel is inserted into the third groove of the adjacent second panel, and at least a portion of the upward locking element of the second panel is inserted into the second downward groove of the first panel.

[0046] It is conceivable that each first coupling profile and each third coupling profile is compatible with each second coupling profile and each fourth coupling profile and can therefore interact and interlock with them. This also applies to the case where the interlocking coupling profiles do not have completely complementary shapes.

[0047] In a preferred embodiment, at least one coupling contour, preferably all coupling contours, are at least partially formed by the core layer.

[0048] The invention also relates to a decorative covering consisting of a plurality of decorative panels according to the invention, preferably connected to each other. In a preferred embodiment, the covering comprises sawn panel parts and / or cut panel parts, wherein each panel part is provided with at least one identifiable tracer material embedded in a polymer matrix.

[0049] The invention also relates to a method for producing a decorative panel comprising the following steps:

[0050] A): preparing a mixture comprising at least one material (e.g. a polymer) and at least one tracer material that is easily identifiable by spectroscopy, preferably atomic spectroscopy, more preferably XRF;

[0051] B): processing the mixture to form at least one panel layer, such as at least one core layer;

[0052] C): fixing (e.g. gluing and / or fusing) at least one further panelling layer to the at least one panelling layer formed during step B);

[0053] Therein, at least one of the panel layers constitutes a core layer and at least one other of the panel layers forms or constitutes a decorative structure of the panel.

[0054] Preferably, during step B), a matrix is ​​formed, such as a polymer matrix, wherein said at least one tracer material is embedded in said matrix.

[0055] Preferably, the mixture preparation during step A) is based on and / or retrieved from a predefined list of material identifiers, wherein the list of material identifiers comprises a list of a plurality of applicable materials and / or combinations of materials, wherein each material and / or each combination of materials is assigned to at least one unique tracer material and / or at least one unique combination of tracer materials, thereby allowing identification of the at least one material applied by the at least one assigned tracer material, wherein the tracer material is susceptible to identification by spectroscopy, preferably atomic spectroscopy, more preferably XRF. The material may be or may comprise a polymeric material and / or a non-polymeric material. In case of using polymers, preferably each polymer and / or each combination of polymers is assigned to at least one unique tracer material and / or at least one unique combination of tracer materials, thereby allowing identification of the at least one polymer applied by the at least one assigned tracer material, wherein the tracer material is susceptible to identification by spectroscopy, preferably atomic spectroscopy, more preferably XRF.

[0056] Preferably, the laminate of panels formed during step C) is cut into panels in a subsequent step D).

[0057] Preferably, the panels are provided with complementary coupling profiles with at least one pair of panel edges, preferably by milling.

[0058] The present invention also relates to a method for identifying at least one polymer of a decorative panel, comprising the following steps:

[0059] i. analyzing the elemental composition of at least one panel and / or at least one panel portion using an elemental spectroscopic analysis system;

[0060] ii. determining the identity of at least one tracer material present in the panel based on the analysis results collected in step i), preferably by using said analysis system; and

[0061] iii. Based on the one or more tracer materials determined during step ii), the identity of the polymer is determined by retrieving the identity of at least one polymer used in the panel from a predefined list of matrix materials, which list of matrix materials can be a list of polymer identifiers, wherein the list of matrix materials, preferably the list of polymer identifiers, comprises a list of multiple applicable matrix materials, such as a list of polymers and / or polymer combinations, wherein each matrix material, such as each polymer and / or each polymer combination, is assigned to at least one unique tracer material and / or at least one unique tracer material combination.

[0062] Alternatively, the method according to the invention can also be used to identify at least one non-polymer material used in a decorative panel, and / or a combination of at least one polymer and / or at least one non-polymer used in a decorative panel. To this end, during step iii), the identity of the material is preferably determined using a cross-reference between each material and / or material combination and at least one (unique / predefined) tracer material and / or a (unique / predefined) tracer material combination.

[0063] In the above method, preferably during step i), at least one panel and / or at least one panel part is exposed to electromagnetic radiation generated by said analysis system. It is further preferred that the wavelength of the radiation is below 10 nm.

[0064] Preferably, the method comprises a step iv) comprising the step of classifying the panels and / or panel parts based on the one or more identified polymers present in the panels determined during step iii) and / or based on the one or more identified tracer materials present in the panels determined during step ii). Preferably, steps ii) and iii) are computer-implemented method steps. It is conceivable that an X-ray fluorescence (XRF) spectrometer is used during step i).

[0065] Preferably, step i) comprises the following sub-steps:

[0066] a): exposing at least one panel and / or at least one panel portion to X-rays generated by said XRF spectrometer;

[0067] b): exciting at least one tracer material embedded in the panel by said X-rays;

[0068] c): detecting secondary X-rays emitted by said at least one tracer material by using said XRF spectrometer;

[0069] d): processing the detected secondary X-rays by the XRF spectrometer to determine the energy and / or spectral position of the emitted secondary X-rays;

[0070] And wherein step ii) comprises the following sub-steps:

[0071] e): Identifying the signature of the tracer material by comparing the energy and / or spectral position of the emitted secondary X-rays with a database comprising data on known tracer materials and their characteristic emission energies and / or spectral positions.

[0072] The determination of the identity of the at least one matrix material (eg polymer) used in the panel according to method step iii) can be based, for example, on the list of matrix materials given below. Tracer Materials Matrix material <![CDATA[Y 2 THE 3 ]]> PVC <![CDATA[CeO 2 ]]> TPU <![CDATA[Nd 2 THE 3 ]]> PET <![CDATA[Gd 2 THE 3 ]]> PP <![CDATA[Dy 2 THE 3 ]]> PE <![CDATA[Yb 2 THE 3 ]]> PS <![CDATA[Y 2 A 3 +At 2 A 3 ]]> <![CDATA[MgO and / or Mg(OH) 2 > <![CDATA[Nd 2 O 3 +Is 2 O 3 ]]> plaster

[0073] Thus, each tracer material and each unique tracer material combination is assigned to a specific matrix material. Such conversion tables are preferably known to manufacturers and disposal companies, in particular recycling companies.

[0074] It is conceivable that at least one tracer material is identified using an identification system, which includes: an illumination source, preferably an X-ray source, which is configured to illuminate the panel to be classified; a detector, preferably an XRF spectrometer, which is configured to detect radiation emitted by the tracer material embedded in the polymer matrix, in particular the emitted secondary X-rays; an analyzer, which is configured to analyze the detected radiation, in particular the secondary X-rays; a data processing system, which is configured to identify the signature of the tracer material in the polymer matrix; and a classification device, which is configured to classify the polymer based on the signature of the tracer material in the polymer matrix.

[0075] In another preferred embodiment, the identification system comprises a filter located between the X-ray source and the panel to be classified, wherein the filter is configured to reduce the noise of the X-rays emitted by the illumination source. It is conceivable that the filter is a metal filter, preferably a metal selected from the group consisting of aluminum (Al), copper (Cu), zirconium (Zr), iron (Fe), molybdenum (Mo), silver (Ag) and indium (In). Preferably, the detector is a semiconductor detector and is preferably made of a material selected from the group consisting of silicon, high purity germanium and cadmium telluride. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The invention will be explained on the basis of the following non-limiting exemplary embodiments shown in the accompanying drawings, in which:

[0077] Figure 1a and 1b shows a schematic cross-sectional view of a decorative panel according to the invention; and

[0078] Figure 2 The method of identifying a polymer in a decorative panel according to the invention is schematically shown. DETAILED DESCRIPTION

[0079] Figure 1a and 1b A cross-sectional view of a decorative panel (100) according to the present invention is shown. The panel (100) comprises a core layer (101), which comprises an upper side (101a) and a lower side (101b). A decorative layer (140) is fixed to the upper side (101a) of the core layer (101). A backing layer (150) is fixed to the lower side (101b) of the core layer (101). The core layer (101) consists of at least one polymer matrix. The polymer matrix is ​​rich in a tracer material (102). The tracer material (102) is a spectrally detectable tracer material. The tracer material can be detected by atomic spectroscopy, preferably by XRF detection. Optionally, one or more layers of the decorative panel (100) contain at least one polymer matrix rich in a tracer material (102). The panel (100) also includes interlocking joint profiles (103, 104, 105, 106).

[0080] Figure 1a A schematic cross-sectional view of a decorative panel (100) according to the present invention is shown, the panel comprising a tracer material (102) embedded in a polymer matrix. The decorative panel (100) comprises a first edge (107) and an opposite second edge (108), the first edge (107) and the second edge (108) having a first coupling profile (103) and a second coupling profile (104), respectively. The first coupling profile (103) comprises a lateral tongue (109). A front region of the lateral tongue (109) is provided with a circular bottom surface. The outer end of the circular bottom surface adjoins an inclined bottom surface. The opposite end of the circular bottom surface adjoins an inclined locking surface. The opposite end of the circular bottom surface adjoins a support surface (110), which forms part of a rear region of the lateral tongue (109). The second coupling profile (104) comprises an upper lip (112) and a lower lip (113) defining a recess (114). The recess (114) has a shape that is complementary to the shape of the lateral tongue (109). More specifically, the top surface of the rear region of the lower lip (113) has a (complementary) rounded shape, configured to cooperate with the rounded front region of the lateral tongue (109), while the front region of the lower lip (113) is provided with an upwardly protruding shoulder, which is configured to cooperate with the supporting surface of the lateral tongue (109). The lower surface of the upper lip (112) is inclined and corresponds to the locking surface of the lateral tongue (109). By inserting the lateral tongue (109) of the panel (100) to be connected into the recess (114), locking at the first edge (107) and the second edge (108) of the adjacent panels (100) is achieved, wherein the panels (100) are initially held in an inclined position. After the lateral tongue (109) is inserted into the recess (114), the panels (100) to be connected will be pivoted (tilted) in a downward direction about an axis parallel to the first edge (107) until both panels (100) are located in the same generally horizontal plane, wherein the locking surface of the lateral tongue (109) will engage with the locking surface of the upper lip (112), and wherein at least the bottom front part is substantially received in the recess (114) with a form fit, and wherein the bearing surface is supported by the shoulder. The locking at the first edge (107) and the second edge (108) results in a locking of the connected panels (100) in the horizontal and vertical directions. The downward tilting locking principle of the first edge (107) and the second edge (108) is a relatively easy locking principle, which greatly facilitates the mutual connection of the panels at these edges (107, 108).

[0081] Figure 1bA schematic cross-sectional view of a decorative panel (100) according to the present invention is shown, the panel comprising a tracer material (102) embedded in a polymer matrix. The decorative panel (100) comprises a complementary third edge (117) and an opposite fourth edge (118), the third edge (117) and the fourth edge (118) having a third connecting profile (105) and a fourth connecting profile (106), respectively. The third connecting profile (105) comprises an upward tongue (119), an upward flank (120) and an upward groove (121) formed between the upward tongue (119) and the upward flank (120). The side of the upward tongue (119) facing the upward flank (120) extends in the direction of the normal N1 of the upper side (101a) of the core layer (101). Therefore, the tangent R1 and the normal N1 of the upper side (101a) of the core layer (101) point to each other (convergent orientation). Due to the convergent orientation of the upward wing (120) and the side of the upward tongue (119) facing the upward wing (120), the upward groove is a closed groove that can only be contacted by a complementary counterpart through deformation of the upward tongue (119). The other side of the upward tongue (119) facing the upward wing (120) forms an alignment edge, which facilitates the connection with the adjacent panel (100). The lower part of the upward wing (120) is oriented diagonally, while the upper part of the upward wing (120) is shown as being substantially vertical and forms a stop surface for the fourth edge (118). Between the inclined part and the substantially vertical part of the upward wing (120), an additional coupling element, in particular an additional protrusion (124), is provided. In this exemplary embodiment, the lower wall portion of the upward groove (121) is oriented substantially horizontally. The fourth edge (118) is substantially complementary to the third edge (117). The fourth coupling profile (106) comprises a downward tongue (125), a downward flank (126) and a downward groove (127) formed between the downward tongue (125) and the downward flank (126). The side of the downward tongue (125) facing the downward flank (126) is located in the direction of the normal N2 of the lower side (101b) of the core layer (101). This means that the tangent R2 of one side of the downward tongue (125) and the normal of the lower side (101b) of the core layer (101) converge with each other. Preferably, the inclination angle of R1 is the same as the inclination angle of R2; therefore, R1 and R2 are preferably parallel. Due to the convergent orientation of the downward flank (126) and the side of the downward tongue (125) facing the downward flank (126), the downward groove (127) is a closed groove that can only be contacted by the upward tongue (119) of the adjacent panel (100) by deformation of the downward tongue (125), with the result that the entrance of the downward groove (127) is (temporarily) widened. The inclined side of the downward tongue (125) also serves as an alignment edge to further facilitate the connection between two panels (100).The other side facing away from the downward flank (126) is of substantially vertical form but is provided with a small cavity (128) configured to cooperate with an additional protrusion (124) of another panel (100). The downward flank (126) is oriented substantially vertically and is provided with a recess (129) adapted to receive an outward protrusion (130) of an upward tongue (119) of an adjacent panel.

[0082] Figure 2 A method for identifying polymers in decorative panels is schematically shown. The figure shows an identification device (200) for classifying panels (100) according to the present invention. The figure shows an illumination source (201) illuminating the decorative panel (100). The panel (100) comprises at least one (optionally, multiple) polymers in a polymer matrix, in which one or more tracer materials (102) are embedded. Radiation (202) emitted by the illumination source (201) excites the tracer material (201) in the polymer matrix in the panel (100). The excited tracer material (102) emits radiation (203). The radiation (203) is captured by a detector (204). Subsequently, an analyzer (205) processes the detected radiation (203). The analyzer (205) compares the detected radiation (203) with a database. The database includes data on known tracer materials (203) in the polymer matrix in the panel (100). Based on the signature of the detected radiation (203), the tracer material (102) can be associated with the polymer in the panel (100). Based on the relationship between the tracer material (102) and the polymer, the panels can be sorted. This has great advantages for recycling programs of post-consumer panels (100).

[0083] In another embodiment, the illumination source (201) is an X-ray source. The panel (100) comprises a polymer matrix embedded with a tracer material (102) sensitive to XRF. The radiation includes primary X-rays emitted by the X-ray source to excite the tracer material in the panel. The excited tracer material (102) emits secondary X-rays (203), i.e., fluorescent X-rays. The secondary X-rays (203) are captured by the detector (204). Subsequently, the analyzer (205) processes the detected secondary X-rays (203). The analyzer (205) compares the detected secondary X-rays (203) with a tracer material database. Based on the signature of the detected secondary X-rays (203), the tracer material (102) is identified, and then the tracer material (102) can be associated with the matrix material used in the panel (100) by using a matrix material retrieval database.

[0084] The latter database (not shown) preferably comprises direct or indirect cross-references between at least one tracer material and at least one matrix material (eg polymer material), as shown in the following table. Tracer Materials Matrix material <![CDATA[Y 2 THE 3 ]]> PVC <![CDATA[CeO 2 ]]> TPU <![CDATA[Nd 2 THE 3 ]]> PET <![CDATA[Gd 2 THE 3 ]]> PP <![CDATA[Dy 2 THE 3 ]]> PE <![CDATA[Yb 2 THE 3 ]]> PS <![CDATA[Y 2 A 3 +At 2 A 3 ]]> <![CDATA[MgO and / or Mg(OH) 2 > <![CDATA[Nd 2 O 3 +Is 2 O 3 ]]> plaster

[0085] Thus, the above-described inventive concepts have been described by way of several illustrative embodiments. It is contemplated that each inventive concept may also be applied without applying the other details of the described examples. It is not necessary to describe in detail all conceivable examples of combinations of the above-described inventive concepts, as those skilled in the art will appreciate that many inventive concepts may be (re)combined to achieve a particular application.

[0086] "Horizontal" refers to a direction extending parallel to a plane defined by the floor panels and which may intersect the core layer. "Vertical" refers to a direction perpendicular to said plane defined by the floor panels. Ordinal numbers used herein, such as "first", "second" and "third", are used for identification purposes only. Thus, the use of the expressions "third locking element" and "second locking element" does not necessarily require the coexistence of a "first locking element".

[0087] The "floor panel" according to the invention can also be used as a wall covering element, ceiling covering element or as an alternative covering element.

[0088] Obviously, the invention is not limited to the working examples shown and described herein, but many variations are possible within the scope of the appended claims, which will be obvious to a person skilled in the art.

[0089] The verb "to comprise" and its variations as used in this patent should be understood to mean not only "to include", but also to mean the phrases "to include", "consisting essentially of", "formed of" and their variations.

Claims

1. A decorative panel, in particular a decorative floor panel, comprising: at least one core layer having an upper side and a lower side; a decorative top structure secured directly or indirectly to the upper side of the core layer; Therein the panel, in particular the core layer, consists at least partially of at least one polymer matrix in which at least one tracer material is embedded, the at least one tracer material being easily identifiable by spectroscopic methods.

2. The panel according to claim 1, wherein At least one tracer material is readily identifiable by atomic spectroscopy.

3. The panel according to claim 1 or 2, wherein: At least one tracer material is readily identifiable by X-ray fluorescence (XRF).

4. A panel according to any one of the preceding claims, wherein At least one tracer material is an element having an atomic number equal to or higher than 30, or comprises an element having an atomic number equal to or higher than 30.

5. A panel according to any one of the preceding claims, wherein At least one tracer material is or comprises at least one solid metal.

6. The panel according to claim 5, wherein The at least one solid metal is selected from the group consisting of germanium (Ge), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), molybdenum (Mo), iodine (I), lutetium (Lu) and tungsten (W).

7. A panel according to any one of the preceding claims, wherein At least one tracer material is a rare earth element, or comprises a rare earth element.

8. The panel according to claim 7, wherein At least one rare earth element is selected from: yttrium (Y), lanthanum (La), neodymium (Nd), samarium (Sm), gadolinium (Gd), cerium (Ce), praseodymium (Pr), europium (Eu), terbium (Tb), dysprosium (Dy), erbium (Er), holmium (Ho), thulium (Tm) and ytterbium (Yb).

9. A panel according to any one of the preceding claims, wherein At least one tracer material comprises at least one rare earth oxide, preferably a rare earth oxide selected from Y2O3, La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3 and Yb2O3.

10. The panel according to claim 9, wherein At least one tracer material comprises a rare earth oxide selected from the group consisting of Y2O3, La2O3, Nd2O3, Gd2O3, Dy2O3, CeO2, Pr2O3, Sm2O3 and Yb2O3.

11. A panel according to claim 9 or 10, wherein At least one tracer material comprises a rare earth oxide selected from the group consisting of Y2O3, La2O3, Pr2O3, Nd2O3, Gd2O3, CeO2, Pr2O3, Sm2O3, Gd2O3, Er2O3 and Yb2O3.

12. A panel according to any one of claims 9 to 11, wherein At least one tracer material comprises a rare earth oxide selected from Eu2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3 and Tm2O3.

13. A panel according to any one of the preceding claims, wherein At least one tracer material comprises monazite and / or bastnasite and / or xenotime and / or is at least partly derived from monazite and / or bastnasite and / or xenotime.

14. A panel according to any one of the preceding claims, wherein The tracer weight concentration of the at least one tracer material in the polymer matrix is ​​in the range of 0.1 to 1.0 grams of tracer material per kilogram of polymer matrix.

15. A panel according to any one of the preceding claims, wherein At least one polymer matrix at least partially consists of a polymer selected from the group consisting of polypropylene (PP), polyurethane (PU), thermoplastic polyurethane (TPU), polystyrene (PS), polyethylene (PE), polyethylene terephthalate (PET) and polyvinyl chloride (PVC).

16. A panel according to any one of the preceding claims, wherein The decorative top structure comprises a plurality of layers.

17. A panel according to any one of the preceding claims, wherein The decorative top structure consists at least partially of a polymer material.

18. The panel according to claim 17, wherein The decorative top structure comprises at least one layer comprising a polymer matrix and at least one tracer material embedded in the polymer matrix.

19. A panel according to any one of the preceding claims, wherein At least one core layer comprises a polymer matrix and at least one tracer material.

20. A panel according to any one of the preceding claims, wherein At least one first panel layer comprises a first polymer matrix and at least one first tracer material, and wherein at least a second panel layer comprises a second polymer matrix and at least one second tracer material.

21. The panel of claim 20, wherein The first polymer matrix and the second polymer matrix consist at least partially of the same polymer.

22. A panel according to claim 20 or 21, wherein The first polymer matrix and the second polymer matrix consist at least partially of different polymers.

23. The panel according to one of claims 20 to 22, wherein The first tracer material and the second tracer material are the same tracer material.

24. The panel according to one of claims 20 to 22, wherein The first tracer material and the second tracer material are different tracer materials.

25. A panel according to any one of the preceding claims, wherein At least a portion of the panel is provided with at least one coating, wherein the coating comprises at least one tracer material.

26. A panel according to any one of the preceding claims, wherein At least a portion of the panel is impregnated, wherein the impregnated portion comprises at least one tracer material.

27. A panel according to any one of the preceding claims, wherein At least one panel layer comprises at least one secondary tracer material formed from magnetic particles.

28. A panel according to any one of the preceding claims, wherein At least one panel layer comprises a plurality of different tracer materials which are easily identifiable by spectroscopy, in particular atomic spectroscopy such as XRF.

29. A panel according to any one of the preceding claims, wherein At least one tracer material is substantially uniformly embedded in the polymer matrix.

30. A panel according to any one of the preceding claims, wherein The decorative top structure comprises at least one decorative layer, preferably a digitally printed decorative layer, and at least one transparent and / or translucent layer at least partially covering the decorative layer.

31. A panel according to any one of the preceding claims, wherein At least a portion of the decorative top structure is releasably secured to the core layer.

32. A panel according to any one of the preceding claims, wherein The panel comprises at least one backing layer releasably secured directly or indirectly to the underside of the core layer.

33. A panel according to any one of the preceding claims, wherein The panel comprises at least one backing layer fixed directly or indirectly to the underside of the core layer, wherein the core layer and the backing layer at least partially consist of the same polymer.

34. A panel according to any one of the preceding claims, wherein The panel comprises at least one backing layer fixed directly or indirectly to the underside of the core layer, wherein the backing layer comprises a polymer matrix and at least one tracer material embedded in the polymer matrix.

35. A panel according to any one of the preceding claims, wherein At least one polymer matrix is ​​at least partially composed of polymers formed from a mixture of virgin polymer material and recycled polymer material.

36. A panel according to any one of the preceding claims, wherein The at least one polymer matrix is ​​enriched with at least one additive, preferably at least one additive selected from the group consisting of talc, chalk, wood, calcium carbonate, titanium dioxide, calcined clay, porcelain, glass particles, glass fibers, carbon particles, silicon particles, (other) mineral fillers, rice, (other) natural fillers.

37. The panel of claim 36, wherein At least one additive is provided with at least one tracer material.

38. A panel according to any one of the preceding claims, wherein The panel comprises a first panel edge comprising a first coupling profile and a second panel edge, preferably opposite the first panel edge, comprising a second coupling profile, the second coupling profile being designed to interlockingly engage with the first coupling profile of an adjacent panel, preferably both horizontally and vertically.

39. The panel of claim 38, wherein The first coupling profile comprises: First upward tenon; at least one first upward flank located at a distance from said upward tongue; a first upward groove formed between the first upward tongue and the first upward wing, wherein the first upward groove is adapted to receive at least a part of a second downward tongue of a second coupling profile of an adjacent panel; and Preferably, at least one first locking element, said first locking element being more preferably arranged on a distal side of said first upward tongue facing away from said upward flank; and wherein the second coupling profile comprises: second downward tenon; at least one second downward flank located at a distance from said downward tongue; a second downward groove formed between the downward tongue and the downward wing, wherein the downward groove is adapted to receive at least a portion of an upward tongue of a first coupling profile of an adjacent panel; and Preferably, at least one second locking element, which is adapted to co-act with a first locking element of an adjacent panel, wherein the second locking element is more preferably arranged at the downward flank.

40. A panel as claimed in claim 38 or 39, wherein The first coupling profile and the second coupling profile are designed in such a way that the two panels can be coupled to one another by a rotational movement and / or by a vertical movement.

41. A panel according to any one of claims 38 to 40, wherein In the coupled state of adjacent panels, the first coupling profile of the panel and the second coupling profile of the adjacent panel are configured such that the two panels can be separated from each other by a rotational movement and / or by a vertical movement and / or by a horizontal movement.

42. A panel according to any one of the preceding claims, wherein The panel comprises at least one third coupling profile and at least one fourth coupling profile at a third panel edge and a fourth panel edge, respectively, the fourth panel edge preferably being opposite the third panel edge, wherein the third coupling profile comprises: a lateral tongue extending in a direction substantially parallel to a plane defined by the panels and / or substantially parallel to an upper side of the core layer; at least one third downward flank located at a distance from said lateral tongue; and a third downward groove formed between the lateral tongue and the third downward flank; Therein, the third coupling profile and the fourth coupling profile are configured such that two panels can be coupled to one another by a rotational movement and / or by a vertical movement and / or by a horizontal movement.

43. The panel of claim 42, wherein The fourth connecting profile comprises a fourth groove, which is configured to accommodate at least a portion of a lateral tongue of the third connecting profile of an adjacent panel, the fourth groove being defined by an upper lip and a lower lip, wherein the lower lip is provided with an upward locking element, wherein in a connected state at least a portion of the lateral tongue of a first panel is inserted into the fourth groove of an adjacent second panel, and wherein at least a portion of the upward locking element of the second panel is inserted into the third downward groove of the first panel, wherein the lower lip preferably extends relative to the upper lip.

44. The panel of claim 43, wherein A fourth locking element is arranged at the distal side of the upward locking element facing away from the fourth groove, wherein the fourth locking element is designed to interact with a locking element of a complementary coupling profile of another panel, in particular a second locking element of a second coupling profile, in the coupled state of the panels.

45. The panel according to one of claims 38 to 41 and one of claims 42 to 44, wherein The first coupling profile and the fourth coupling profile are identical.

46. ​​A decorative covering, in particular a decorative floor covering, comprising a plurality of mutually coupled decorative panels according to any one of claims 1 to 40.

47. A method of manufacturing a decorative panel according to any one of claims 1 to 45, comprising the steps of: A): preparing a mixture comprising at least one polymer and at least one tracer material, the at least one tracer material being easily identifiable by spectroscopy, preferably atomic spectroscopy, more preferably XRF; B): processing said mixture to form at least one panel layer, such as at least one core layer, said at least one panel layer comprising a matrix of said polymer and said at least one tracer material embedded in said matrix; C): fixing, for example gluing and / or fusing, at least one further panelling layer to the at least one panelling layer formed during step B); Therein, at least one of the panel layers constitutes a core layer and at least one other of the panel layers forms or constitutes a decorative structure of the panel.

48. The method of claim 47, wherein: The preparation of the mixture during step A) is based on and / or retrieved from a predefined list of polymer identifiers, wherein the list of polymer identifiers comprises a list of a plurality of applicable polymers and / or polymer combinations, wherein each polymer and / or each polymer combination is assigned to at least one unique tracer material and / or at least one unique tracer material combination, thereby allowing identification of the applied at least one polymer by means of the at least one assigned tracer material, wherein the tracer material is susceptible to identification by spectroscopy, preferably atomic spectroscopy, more preferably XRF.

49. The method according to claim 47 or 48, wherein: The laminate of panels formed during step C) is cut into panels in a subsequent step D).

50. The method according to one of claims 47 to 49, wherein: The panels are provided with complementary coupling profiles at at least one pair of panel edges, preferably by milling.

51. A method of identifying a polymer of a decorative panel or a panel portion thereof according to any one of claims 1 to 45, in particular a method of identifying a polymer of a decorative panel or a panel portion thereof manufactured by applying a method according to any one of claims 47 to 50, comprising the following steps: i. analyzing the elemental composition of at least one panel and / or at least one panel portion using an elemental spectroscopic analysis system; ii. determining the identity of at least one tracer material present in the panel, based on the analysis results collected in step i), preferably by using said analysis system; as well as iii. Based on the one or more tracer materials determined during step ii), determining the identity of at least one polymer used in the panel by retrieving the identity of the polymer from a predefined list of polymer identifiers, wherein the list of polymer identifiers comprises a list of multiple applicable polymers and / or polymer combinations, wherein each polymer and / or each polymer combination is assigned to at least one unique tracer material and / or at least one unique tracer material combination.

52. The method of claim 51, wherein: During step i), the at least one panel and / or at least one panel part is subjected to electromagnetic radiation generated by the analysis system.

53. The method of claim 52, wherein: The wavelength of the radiation is below 10 nm.

54. The method according to one of claims 51 to 53, wherein: The method comprises step iv) comprising the step of classifying the panels and / or panel parts based on the one or more identified polymers present in the panel determined during step iii) and / or based on the one or more identified tracer materials present in the panel determined during step ii).

55. The method according to one of claims 51 to 54, wherein: Step ii) and step iii) are computer-implemented method steps.

56. The method according to one of claims 51 to 55, wherein: During step i) an X-ray fluorescence (XRF) spectrometer is used.

57. The method of claim 56, wherein: Step i) comprises the following sub-steps: a): exposing at least one panel and / or at least one panel portion to X-rays generated by said XRF spectrometer; b): exciting at least one tracer material embedded in the panel by said X-rays; c): detecting secondary X-rays emitted by said at least one tracer material by using said XRF spectrometer; d): processing the detected secondary X-rays by the XRF spectrometer to determine the energy and / or spectral position of the emitted secondary X-rays; And wherein step ii) comprises the following sub-steps: e): Identifying the signature of the tracer material by comparing the energy and / or spectral position of the emitted secondary X-rays with a database comprising data on known tracer materials and their characteristic emission energies and / or spectral positions.

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