Decorative panel, core layer, and method of producing such a panel

Abstract

The invention relates to a decorative panel, in particular a floor panel, a wall panel, or a ceiling panel, comprising: a core layer, and a decorative top structure directly or indirectly affixed to a top surface of said core layer. The invention also relate to a core layer for use in such a decorative panel. The invention further relates to a method of producing a decorative panel, in particular a decorative panel according to the invention.

Description

[0001] Decorative panel, core layer, and method of producing such a panel

[0002] The invention relates to a decorative panel, in particular a floor panel, a wall panel, or a ceiling panel, comprising: a core layer, and a decorative top structure directly or indirectly affixed to a top surface of said core layer. The invention also relates to a core layer for use in such a decorative panel. The invention further relates to a method of producing a decorative panel, in particular a decorative panel according to the invention.

[0003] In the last decades many improvements have been observed in the world of decorative panels, such as floor panels and wall panels. These improvements cover various aspects of the decorative panels, such as, for example, improving the aesthetical appearance of the panels, improving mechanical coupling profiles of the panels, improving the acoustic properties of the panels, improving the scratch resistance of the panel, and improving the core composition of the panels. With respect to this latter aspect, a trend is visible that traditional core layer materials, like medium density board (MDF) and high density board (HDF) are partially replaced by other materials, like PVC based compositions. Contrary to MDF and HDF, PVC is waterproof and therefore easy to maintain and moreover exhibits relatively attractive noise reducing properties. However, the use of PVC in core compositions of decorative panels is not undisputed. As this PVC is typically softened by using hazardous plasticizers, like phthalates, health risks may be involved. Moreover, during the production of PVC toxic chemicals are used and toxic by-products and waste are generated. Furthermore, in case of a fire, PVC based panels may generate carcinogens called dioxins and furans, which is less preferred from a health safety and environmental point of view. In addition to the above, the carbon footprint of PVC, also referred to as embodied carbon, is substantial, which also puts pressure on the use of PVC in core layers of decorative panels. As awareness is increasing regarding the health safety of materials as well as regarding the environment, a response is being demanded from the industry and its customers to also use alternative raw materials for manufacturing decorative panels. More in particular, there is a need to develop a core composition of the decorative panel, which is relatively health safe and which seriously reduces the carbon footprint to spare the environment as much as possible. It is therefore a first objective of the present invention to provide a decorative panel having a relatively low carbon footprint.

[0004] It is therefore a second objective of the present invention to provide a decorative panel having an improved core composition.

[0005] It is therefore a third objective of the present invention to provide a decorative panel having a more health safe and / or environmental friendly core composition.

[0006] At least one of these objectives can be achieved by providing a decorative panel according to the preamble, comprising:

[0007] • a core layer; and

[0008] • a decorative top structure directly or indirectly affixed to a top surface of said core layer, wherein said core layer is at least partially composed of:

[0009] • a matrix material at least partially composed of recycled polyethylene and / or biobased polyethylene and / or another recycled and / or biobased thermoplastic polyolefin;

[0010] • cork particles dispersed in said matrix material; and

[0011] • at least one (further) filler dispersed in said matrix material, wherein said filler is preferably at least one filler chosen from the group consisting of: a silicate and waste slag and / or wherein said filler comprises at least one inorganic fraction, wherein said inorganic fraction comprises at least one silicate, in particular quartz (SiO2), and alumina (AI2O3).

[0012] The decorative panel according to the invention has several advantages. First of all, since the material composition of the core layer is either based upon a recycled thermoplastic polyolefin, such as recycled polyethylene and / or a biobased thermoplastic polyolefin, such as biobased polyethylene, the carbon footprint of the core composition and hence of the decorative panel as such can be reduced significantly, in particular compared to virgin fossil based polymers (based upon non-renewable fossil fuel). Moreover, these recycled and / or biobased thermoplastic polyolefins are relatively health safe compared to PVC, as these thermoplastic polyolefins do not require hazardous plasticizers, such as phthalates, to make the polymer more flexible for the aimed application. Moreover, the production of these thermoplastic polyolefins (contrary to PVC) does not lead to toxic by-products, and these thermoplastic polyolefins (contrary to PVC) will not release extremely potent carcinogens called dioxins and furans in the case of a fire. Hence, thermoplastic polyolefins have significant advantages over PVC, and the use of recycled and / or biobased thermoplastic polyolefins further reduces the embodied carbon (carbon footprint) of the core composition, and hence of the decorative panel as such. To keep the carbon footprint of the core composition, and hence of the decorative panel, as limited as possible, it may be preferred that said core layer is free of virgin fossil-based polymers. It may also be preferred that said core layer is free of polyvinyl chloride.

[0013] The core composition also comprises cork particles to reduce the density of the core layer, which leads to a relatively light-weight core layer, and hence of the decorative panel as such, which is beneficial both from an economic and practical point of view. Moreover, the presence of cork particles in the core layer improves the sound dampening properties (acoustic properties) and thermal properties of the core layer, and hence of the decorative panel as such, and leads to comfort benefits. The cork particles are natural cork particles, which may be virgin cork particles, or recycled cork particles, or a mixture thereof. Said recycled (natural) cork particles may come from waste / scrap / by-products of the cork industry, and / or may be recycled post-consumer cork (cork stoppers or other applications such as flooring renovations). The density of the cork particles is preferably 110-130 kg / m3. The cork particles are normally created by grinding raw cork, wherein the particles preferably have an average diameter of 0.5 mm, and preferably below 1 mm. Preferably, the cork is present in an amount of less than 10 percent by weight of the core layer. This allows the weight percentage of thermoplastic matrix material, in particular PE matrix material, as well as the weight percentage of further filler, in particular inorganic filler, to remain sufficiently high to achieve among others sufficient rigidity of the panel as such. Cork as raw material can be extracted (harvested) from the bark of an cork oak tree. The first harvest, which is known as “desbbia”, produces cork of an irregular structure, while nine years later the second harvest produces material with a regular structure, and less hard properties. Preferably, the first and second bark stripped from the cork oak are used as raw material for the cork particles present in the core composition. The cork granules (particles) are normally obtained using several different types of mills and after grinding after which the granules are normally cleaned, typically followed by drying using forced circulation of hot air by means of rotating driers, giving the granulate the preferred cork particle moisture content of 4 percent or less.

[0014] The core composition further comprises at least one other filler to make the core layer more rigid and typically also to reduce the cost price of the core composition, wherein said at least one other filler is at least one silicate, and / or at least one waste slag obtained from waste incineration, and / or fly ash, and / or combinations thereof. Further details and examples will be given in the description below.

[0015] The abovementioned filler materials of the core layer are dispersed as particles in said polymeric matrix material, which means that these particles are arranged and / or incorporated (with)in said matrix material. This dispersion can be a homogeneous dispersion or a non-homogeneous dispersion. The particle density may be substantially constant or may vary along the thickness of the core layer, and / or along the length and / or width of the core layer.

[0016] At least one recycled and / or biobased thermoplastic polyolefin used as at least a part of the matrix material of the core composition is preferably recycled and / or biobased polyethylene. Polyethylene has shown to be the most suitable thermoplastic polyolefin for the application as matrix material in the core layer. Although it is imaginable that the matrix material comprises a mixture of recycled polyethylene and biobased polyethylene, it is often preferred from a practical point of view that that the matrix material comprises either recycled polyethylene or biobased polyethylene. The preference to use polyethylene in the matrix material (or as matrix material) does not exclude the presence of one or more other thermoplastic polyolefins, preferably other recycled and / or biobased thermoplastic polyolefins, such as polypropylene. Such one or more other thermoplastic polyolefins are typically though not necessarily present in (significantly) smaller amount, such as trace amounts, compared to the amount of polyethylene used in the matrix material. However, it is also imaginable that the core layer is free of polyethylene. Additionally or alternatively, the core layer may comprise at least one (other) recycled and / or biobased thermoplastic polyolefin, such as polypropylene (PP), preferably bio-PP derived from renewable hydrocarbons obtained from plantbased sources, such as vegetable oils or bioethanol; and / or polyethylene terephthalate (PET), preferably bio-PET derived from plant-based ethylene glycol (such as from sugarcane or com); and / or polybutene (PB), preferably bio-PB-1 derived from renewable sources, typically plant-based raw materials like com or sugarcane. Instead of or in addition to at least one recycled and / or biobased thermoplastic polyolefin, the core layer may comprise at least one other recycled and / or biobased thermoplastic polyolefin, such as polylactic Acid (PLA), polyhydroxyalkanoates (PHA), polybutylene succinate (PBS), polyethylene furanoate (PEF), bio-polyamide (bio-PA), polytrimethylene terephthalate (bio-PTT), and / or mixtures of two or more of these thermoplastic materials.

[0017] In case recycled polyethylene is used in the matrix material, preferably recycled high density polyethylene (HDPE) is used. HDPE has several advantages over low density polyethylene (LDPE), such as an improved material rigidity, which is typically desired in decorative panels.

[0018] In case at least one biobased polymer, such as biobased polyethylene is used in the matrix material, said biobased polymer, such as biobased polyethylene, is a plant-based polymer, often a crop-based polymer, such as a biobased polymer obtained from sugar cane, sugar beet, vegetable oil, palm oil, potato starch, and / or wheat grain. However, in this respect plant based polyethylene derived from algae may also be understood to fall under the scope of the term plant-based. These raw materials are often also used for alimentary purposes. It is also imaginable that in case at least one biobased polymer, such as biobased polyethylene is used in the matrix material, said biobased polymer, such as biobased polyethylene, may be a bio-circular material, being a material coming from organic scrap or organic byproducts and / or a recycled biobased material. Examples of these bio-circular materials are: tall oil, used cooking oil, and organic scraps from the food industry.

[0019] The building block for biobased polyethylene is biobased ethylene which is transformed into polyethylene through conventional catalyst-driven polymerization. This building block (biobased ethylene) can be generated in various manners, such as (i) conversion of biomass, such as sugar cane and sugar beet, through biochemical and thermochemical routes wherein sugar of biomass (e.g. sugar cane) is fermented into ethanol, wherein said ethanol is dehydrated to form ethylene, (ii) cracking of bio-naphtha generated during the processing of renewables feedstocks through technologies as Fischer-Tropsch conversion or hydrotreating, and (iii) by microorganisms. Hence, it is imaginable, and may even be preferred, that said matrix material is at least partially, preferably entirely, composed of biobased polyethylene made out of dehydrated bio-ethanol.

[0020] In an embodiment, said core layer comprises recycled polyethylene and / or biobased polyethylene in an amount of at least 35 percent by weight of the core layer. In case the core layer comprises recycled polyethylene, this recycled polyethylene is may be present in an amount of at least 35 percent, and preferably less than 55 percent, by weight of the core layer. In case the core layer comprises biobased polyethylene, this biobased polyethylene may be in an amount of at least 35 percent or at least 40 percent, and preferably less than 90 percent, by weight of the core layer.

[0021] The polyethylene, preferably biobased polyethylene, of the matrix material may be a fibre reinforced polyethylene, wherein the fibers are preferably natural fibers, such as wood fibers or plant fibers. This fiber reinforcement may further increase the rigidity of the core layer and hence of the decorative panel as such.

[0022] The core layer, in particular the matrix material, may comprise at least one inert filler (in addition to si licate(s) and / or slag), such as a natural mineral filler like, for example, calcium carbonate, and / or at least one natural biobased filler (as also addressed above), such as wood particles, for example. This natural filler may, for example, be present in the matrix material, in an amount of between 35 and 45 percent by weight of the matrix material, and possibly in a reduced weight percentage in the core layer (composition) as such. For example, this additional natural filler may be present in the core layer in an amount of between 5 and 45 weight percent of the core layer.

[0023] It may be advantageous in case said polymeric matrix material has a melt flow index of between 2 and 10, preferably between 4 and 8, g / 10min under the application of a standard weight of 5 kg and a temperature of 190 degrees Celsius, preferably according to ASTM D1238. This allows and secures sufficient flow properties at elevated temperature to shape and form the core layer, for example in a pressing mould. The cork particles dispersed in the matrix material typically have a particle size (granule size) between 0.25 and 3mm, more in particular between 0.5 and 1.0mm. Preferably, a majority, more preferably at least 90 percent, of said cork particles (or cork granules) has a diameter smaller than 1 mm. At least 90 percent of said cork particles may have a particle size capable of passing through a sieve with an aperture size of 1 mm. This relatively small size facilitates a homogeneous dispersion of the particles within the core layer. The core layer preferably comprises cork particles in an amount of at least 20 percent by volume of the core layer. The core layer preferably comprises cork particles in an amount of between 3 and 10 percent, preferably between 4 and 6 percent, such as 5 percent, by weight of the core layer. Hence, the volume content of cork in the core layer normally exceeds the mass content of cork in the core layer. The average specific weight of the cork particles in the core layer is preferably situated between 110 and 130 kg / m3.

[0024] As indicated above, the core layer may comprise one or more silicates. A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula [SiO(4-2x)-4-x]n, where 0 < x < 2. This silicate is preferably a silicate mineral (rock- or clay-forming minerals made up of silicate group). At least one silicate is preferably formed by quartz (SiO2). Balancing the charges of the silicate anions are metal cations, Mx+. Typical cations are Mg2+, Fe2+, and Na+. Preferably, at least one silicate formed by at least one bentonite, preferably sodium bentonite, in particular activated sodium bentonite. Bentonite constitutes an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. An activated sodium bentonite is a modified bentonite, for example by adding sodium carbonate (or another sodium salt) to a calcium / magnesium bentonite in the presence of water, which results in sodium ions to enter the interlayer and calcium / magnesium carbonates precipitate outside. As such, activated sodium bentonite is known.

[0025] At least one silicate, preferably at least one bentonite, used in the core layer is preferably chosen from the group consisting of: montmorillonita, quartz, quartz dolomite, feldspar, and mixtures of two or more of these silicates. In case of a silicate mixture, this mixture may e.g. comprise montmorillonita in an amount of at least 75 percent by weight of the silicate mixture, feldspar in an amount of 4-5 weight percent, and dolomite in an amount of 0.5-1 weight percent. A mixture of feldspar and quartz may also be preferred to increase the silicate content (over alumina) content, which may be in favour of the thermal stability and mechanical strength and / or rigidity of the core layer, and hence of the panel as such. To this end, the weight ratio silicate to alumina in the inorganic fraction is preferably at least 3, preferably at least 3.5, and optionally less than 4.

[0026] The total amount of silicate(s) in the core layer may be situated between 5 and 15 percent by weight of the core layer. The addition of one or more silicates, preferably bentonite, such as sodium bentonite, to the core, is used to increase the rigidity and to reduce the elasticity of the core layer. A silicate free core composition may, for example, exhibit a Young’s modulus of about 700 MPa, while addition of silicate in an amount of between 5 and 15 weight percent of the core layer may increase the Young’s modulus to more favourable values of between 1 ,000 and 1 ,600 MPa. A Young’s modulus of the core layer of at least 1 ,000 MPa, preferably at least 1 ,200 MPa, is preferred for the intended use as decorative panel.

[0027] The silicate is typically dispersed as powder (silicate particles) in the matrix material. The silicate is preferably substantially entirely encapsulated by the matrix material. The same applies to the cork particles and one or more other (optional) fillers used in the matrix materials.

[0028] It is imaginable that the core layer comprises at least one silicate, and wherein the core layer is free of waste slag. It is also imaginable that the core layer comprises waste slag, and wherein the core layer is free of silicate.

[0029] As indicated above, the core layer may comprise waste slag. This waste slag is preferably obtained from the incineration of solid waste incineration, preferably municipal solid waste incineration. To this end, solid waste may be burned at a relative high temperature of about 1000 to 1200 degrees Celsius, possibly in the presence of additional or excess oxygen, which creates combustion products, such as waste slag and fly ash. Preferably, this waste slag is purified waste slag, wherein heavy metals originally present in the waste slag have been removed. Hence, the waste slag is preferably free of heavy metals. The amount of waste slag in the core layer may, for example, be situated between 10 and 30 percent by weight of the core layer. The waste slag may comprise various constituents, and typically comprises glass material, ceramic material, and sand.

[0030] As indicated above, at least one filler preferably comprises an inorganic fraction. This inorganic fraction may form a part of said filler or may form said entire filler. Preferably, said inorganic fraction comprises at least one silicate, in particular quartz (SiCh), and alumina (AI2O3), which mixture may in specific embodiments be classified as aluminosilicate. This inorganic fraction is preferably free of metals. The inorganic fraction typically contributes to the rigidity of the core layer and hence of the panel as such. To this end, the weight ratio silicate to alumina in the inorganic fraction is preferably at least 3, preferably at least 3.5, and optionally less than 4. The wherein inorganic fraction of the filler is preferably present in the core layer (2) in an amount of between 15 and 40 percent, preferably between 18 and 30 percent, such as between 20 and 25 percent, by weight of the core layer. The inorganic fraction (inorganic filler) of the at least one filler is dispersed as particles, such as powder, in the polymer matrix. The inorganic fraction may be obtained from and / / or may be formed by greenware, preferably greenware that is a waste product obtained from the ceramic industry. Greenware refers to clay which has not been subjected to a firing process. This inorganic, preferably non-metallic, greenware can be present as ground powder, scrap, fragments, shards, etcetera, in the core layer as such. It is imaginable that this greenware material used as filler in the core layer comprises at least one further inorganic non-metallic constituent, in addition to said at least one silicate and alumina, wherein said at least one further inorganic non-metallic constituent is preferably chosen from the group consisting of: zirconium oxide, bismuth oxide, magnesium oxide, barium titanate, cordierite, boron nitride, tungsten carbide, tantalum carbide, titanium carbide, niobium carbide, zirconium carbide, boron carbide, hafnium carbide, silicon carbide, niobium boron carbide, aluminium nitride, titanium nitride, zirconium nitride, tantalum nitride, hafnium nitride, niobium nitride, boron nitride, silicon nitride, titanium boride, chromium boride, zirconium boride, tantalum boride, molybdenum boride, tungsten boride, cerium sulphide, titanium sulphide, magnesium sulphide, zirconium sulphide and mixtures and alloys of these. Preferably, the inorganic filler, in particular greenware filler, is preferably present in particles with different particles sizes. This will further improve the rigidity of the core layer and hence of the panel as such. T 0 this end, it may be advantageous in case the inorganic fraction, in particular the inorganic filler, such as the greenware filler, is dispersed as particles in the polymer matrix, wherein at least 25 weight percent of the particles has a diameter larger than 180 micron, and / or wherein at least wherein at least 20 weight percent of the particles has a diameter larger than 250 micron, and / or wherein at least 10 weight percent of the particles has a diameter larger than 500 micron.

[0031] In additional to the thermoplastic material of the core layer, the core layer may comprise an organic filler and / or organic additive, wherein said organic filler and / or additive preferably comprises at least one organic substance or constituent chosen from the group consisting of: an unsaturated hydrocarbon; at least one triglyceride, preferably at least one triglyceride composed of glycerol and at least one fatty acid; soybean oil, and mixtures of two or more of these substances. Said at least one fatty acid may comprise at least one or a mixture of two or more of the following fatty acids: at least one polyunsaturated fatty acid, such as linoleic acid and / or alpha-linolenic acid; at least one mono-unsaturated fatty acid, such as oleic acid; and at least one saturated fatty acid, such as palmitic acid and / or stearic acid. In case of soybean oil (soya oil), the bulk of this material is commonly composed of triglycerides, which are molecules composed of one glycerol molecule and three fatty acids. Hence, the core layer may comprise at least one oil, preferably a natural fatty oil, such as soya oil or palm oil, preferably an in amount of between 1 and 3 percent by weight of the core layer. This oil is often added to prevent dust formation during production of the core layer and of the decorative panel as such.

[0032] Optionally, the core layer may further comprise a binding agent for binding the components of the core layer, wherein said binding agent is preferably a water based resin (EVA), and / or melamine urea resin glue, and / or a natural and / or biobased binding agent.

[0033] Optionally, the core layer comprises at least one compatibilizer to improve the bonding between the typically the thermoplastic material and the cork particles, which may have a mutually different polarity. A suitable of compatibilizer is for example maleic anhydride which may be grafted onto the thermoplastic material, such as polyethylene material. The decorative top structure normally comprises at least one decorative layer, and preferably at least one protective layer covering said decorative layer. These one or more protective layers are typically at least partially transparent and / or translucent layers allowing the decorative layer to remain visible. At least one protective layer may form a wear layer and / or at least one protective layer may form a scratch resistant top coating. The top surface of the decorative top structure may be provided with a relief pattern (embossing), wherein said relief pattern is preferably aligned with a decorative image of the decorative layer (embossing in register). The decorative layer may for example formed by a printed decorative layer, in particular a digitally printed decorative layer, or by a veneer layer, or by a decorative film. Said veneer layer may optionally be or comprise at least one wood veneer layer. The protective layer may be omitted, in particular in this latter case, although it is imaginable that in case of wood veneer layer a protective oil or other protective varnish layer is applied on top of said wood veneer layer. It is imaginable that at least one veneer layer is formed by a cork based veneer layer. In an embodiment, said cork based veneer layer may be directly or indirectly attached, for example by gluing of fusion, to said core layer, wherein at least one decorative layer, such as a wood veneer layer and / or printed decorative layer, may be directly or indirectly attached to said cork based layer, wherein optionally a protective layer is applied on top.

[0034] The decorative panel may comprise a backing layer attached, directly or indirectly, to a bottom surface of the core layer. The backing layer may be a cork based backing layer, preferably at least partially composed of a mixture of a polymeric material and cork particles. The polymeric material is preferably a recycled and / or biobased polymeric material and / or may at least partially by formed by a polyurethane resin.

[0035] The decorative panel may comprise an intermediate layer situated in between the decorative top structure and the core layer, wherein the intermediate layer may be a cork based intermediate layer, preferably at least partially composed of a mixture of a polymeric material and cork particles. The intermediate layer may act as balancing layer and / or sound dampening layer and / or comfort layer. The polymeric material is preferably a recycled and / or biobased polymeric material and / or may at least partially by formed by a polyurethane resin. The composition of the backing layer (if applied) and the intermediate layer (if applied) may be identical. The purpose of applying this layer may e.g. be to improve the sound dampening properties, and / or the mechanical properties, and / or the comfort properties of the decorative panels.

[0036] The decorative top structure may be attached to the core layer by means of gluing and / or fusion, preferably by means of hot pressing. In case of gluing, preferably a water based glue, such as an EVA glue made from a blend of ethylene and vinyl acetate. The use of EVA glue leads to a robust and water resistant bonding as a well as its elasticity. Other glues, such as hot melt glues, may also be used. It is imaginable, in case of hot pressing, that a separate glue layer can be omitted, whereas the thermoplastic material in the core layer may fulfil the role of adhesive to bond the decorative top structure.

[0037] The panel preferably comprises at at least one pair of opposing side edges with complementary coupling profiles allowing intercoupling of adjacent decorative panels. This allows decorative panels according to the invention for example to realize a so-called floating (unglued) floor covering or wall covering. Each side edge of the panel may be provided with a coupling profile. Each coupling profile may comprise one or more tongues and / or one or more grooves. The coupling profiles may be formed substantially out of the core layer material (by removal of core layer material at the side edges).

[0038] The panel may be an oblong panel. The panel may be rectangular or may have an alternative polygon shape, such as e.g. a triangular shape, a hexagonal shape, and a parallelogrammatic shape. The thickness of the core layer may vary, but is often situated between 4 and 10 mm, preferably between 4.5 and 8 mm.

[0039] The invention also relates to a core layer for use in a decorative panel according to the invention, wherein the core layer comprises a matrix material at least partially composed of recycled polyethylene and / or biobased polyethylene; cork particles dispersed in said matrix material, and at least one further filler dispersed in said, wherein said further filler is at least one filler chosen from the group consisting of: a silicate and waste slag.

[0040] The invention further relates to a method of producing a decorative panel, in particular a panel according to the invention, comprising the steps of: a) Providing and mixing: i. a matrix material at least partially composed of recycled polymer, preferably recycled polyethylene and / or biobased polymer, preferably biobased polyethylene; ii. cork particles, preferably in an amount of between 3 and 10 percent, preferably between 4 and 6 percent, such as 5 percent, by weight of the core layer; and iii. at least one filler, wherein said filler is at least one filler chosen from the group consisting of: a silicate and waste slag, and / or wherein said filler comprises an inorganic fraction, wherein said inorganic fraction comprises at least one silicate, in particular quartz (SiO2), and alumina (AI2O3); b) shaping, in particular (press) moulding and / or extruding, said mixture created during step a) to form a core layer; and c) affixing, directly or indirectly, a decorative top structure on top of said core layer.

[0041] During step a), the raw materials are preferably mechanically mixed and fed into a press (press mould), for example at temperatures in the range of 150° C to 220° C for a period of time, such as between 300 and 600 seconds. This composite core layer material has shown to have excellent physicochemical and mechanical properties and has high intrinsic resistance, suitable to its application.

[0042] Step b) preferably takes place at elevated temperature exceeding the softening temperature of said recycled polyethylene and / or biobased polyethylene, and for a period of time which is preferably situated in between 1 and 3 hours.

[0043] Step b) is preferably carried out by using a continuous double belt press, more preferably wherein said continuous double belt press has a heating zone followed by a cooling zone. The heating zone typically comprises one or more heating elements, and the cooling zone typically comprises one or more cooling elements. The double belt press is preferably a height adjustable height press, wherein the distance between opposite belt can be adjusted. This allows the core layer to be provided with a thickness of choice. It is imaginable that the core layer is an extruded core layer. To this end, during step A) optionally pallets of said mixture are prepared, which can subsequently be extruded during step B).

[0044] Preferably, during step b) the mixture of step a) is compressed in a press with a compression force less than 30 kN, preferably in the range of 10-20 kN. Preferably, the compression during step b) is carried out at a temperature in the range of 160- 200 °C and / or preferably for a hot compression time between 24-180 seconds. This compression force is relatively low which leads to several advantages. As cork is a lightweight, cellular material with a high capacity for energy absorption, higher pressures can cause the collapse of its unique cellular structure, negatively affecting the mechanical properties and elasticity of the final product. Lower pressures help preserve the integrity of the cork cells, maintaining desirable properties like compressibility and resilience. Moreover, higher pressure can lead to excessive deformation or even destruction of the cork particles, which could compromise the mixture’s intended properties, such as thermal and acoustic insulation. Lower pressure (< 30 kN) maintains the balance between bonding the thermoplastic material and cork while minimizing unwanted deformation. Lower pressure decreases the risk of the molten thermoplastic material flowing excessively, reducing the formation of "flash" (excess material that overflows at the mould edges). High pressures might cause excessive squeezing of the thermoplastic, leading to material wastage and the need for additional trimming processes. Additionally, lower compression pressures provide enough force to bond the thermoplastic to the cork particles without compacting the cork too much. This ensures an satisfying combination of both materials’ properties without overcompressing the cork, which would diminish its natural characteristics like low density and elasticity. Moreover, using lower pressures reduces wear and tear on the equipment, prolonging the life of moulds and presses. High pressure puts more strain on the equipment, potentially increasing maintenance needs and reducing operational efficiency over time. Furthermore, lower pressures reduce the overall energy consumption during the process. High pressures require more energy to maintain, which can make the manufacturing process less efficient and more expensive.

[0045] In case extrusion is used during step b), the extrusion temperature is preferably to ensure proper melting of the thermoplastic material, in particular polyethylene, without degrading the cork particles. For example, PE typically melts at temperatures around 130-160°C, while cork typically begins to degrade at higher temperatures (above 200°C), as a result of which the extrusion temperature for this specific combination of material is preferably situated between 160 and 200 degrees Celsius.

[0046] It is imaginable that during a method step d) at least one backing layer, preferably cork based backing layer, is applied, directly or indirectly, to the bottom surface of the core layer.

[0047] The method may comprise step e), performed after step c), relating to profiling of at least one pair of opposite side edges of the decorative panel to realize complementary coupling profiles allowing interlocking of adjacent decorative panels. This profiling step can be performed by milling the core layer to form the coupling profiles.

[0048] After formation of the core layer, it may be preferred to subject the core layer to a heat treatment (step f) to anneal the core layer. Annealing is defined as a process wherein the core layer undergoes a heat treatment to a certain temperature, is kept there for a definite time, and is then cooled to room temperature in order to alter the material properties. More in particular, during this heat treatment, the core layer is preferably maintained at an elevated temperature below the glass transition temperature of the recycled polymer, preferably recycled polyethylene and / or biobased polymer, preferably biobased polyethylene, in order to relieve the internal stresses introduced during step a) and / or step b). The annealing process is time and temperature dependent. For example, this heat treatment step f) could be performed during 4 hours at a constant (oven) temperature of 80 degrees Celsius.

[0049] Step c) may be carried out after cooling of the core layer to a temperature below said softening temperature and preferably (still) above room temperature. This may lead to the situation wherein the core layer is sufficiently stable, but still has some tacky properties which facilitates the attachments of one or more further layers to the core layer. Such an intermediate cooling phase (step g), carried out prior to step c) may also be considered as a stabilization phase, and may take multiple days or weeks, such as 14-16 days. It is imaginable that during step c) at least one adhesive (layer) is applied to bond the core layer to the decorative top structure.

[0050] It is imaginable that during step c) at least one intermediate layer, preferably intermediate cork-based layer, is applied onto the top surface of the core layer, wherein the decorative top structure is applied onto the top surface of the intermediate layer.

[0051] Further embodiments of the invention are set out in the non-limitative set of clauses presented below:

[0052] 1. Decorative panel (1 ), in particular a floor panel, a wall panel, or a ceiling panel, comprising:

[0053] • a core layer (2); and

[0054] • a decorative top structure (6) directly or indirectly affixed to a top surface of said core layer (2), wherein said core layer (2) is at least partially composed of:

[0055] • a matrix material at least partially composed of recycled thermoplastic material and / or biobased thermoplastic material, such as recycled polyethylene and / or biobased polyethylene;

[0056] • cork particles dispersed in said matrix material; and

[0057] • at least one filler dispersed in said matrix material, wherein said filler is at least one filler chosen from the group consisting of: a silicate, in particular quartz (SiCh), and waste slag; and / or wherein said filler comprises an inorganic fraction, wherein said inorganic fraction comprises at least one silicate, in particular quartz (SiO2), and alumina (AI2O3).

[0058] 2. Decorative panel (1) according to clause 1 , wherein said core layer (2) is free of virgin fossil-based polymers.

[0059] 3. Decorative panel (1) according to clause 1 or 2, wherein said core layer (2) is free of polyvinyl chloride. 4. Decorative panel (1) according to any of the preceding clauses, wherein said matrix material is at least partially, preferably entirely composed of recycled high density polyethylene (HDPE).

[0060] 5. Decorative panel (1) according to any of the preceding clauses, wherein said matrix material is at least partially, preferably entirely composed of biobased polyethylene, wherein said biobased polyethylene is plant-based polyethylene, in particular obtained from sugar cane, sugar beet, palm oil, and / or wheat grain.

[0061] 6. Decorative panel (1) according to any of the preceding clauses, wherein said matrix material is at least partially, preferably entirely composed of biobased polyethylene made out of dehydrated bio-ethanol.

[0062] 7. Decorative panel (1) according to any of the preceding clauses, wherein said core layer comprises recycled polyethylene and / or biobased polyethylene in an amount of at least 35 percent by weight of the core layer.

[0063] 8. Decorative panel (1) according to any of the preceding clauses, wherein said core layer comprises recycled polyethylene in an amount of at least 35 percent, and preferably less than 55 percent, by weight of the core layer.

[0064] 9. Decorative panel (1) according to any of the preceding clauses, wherein said core layer comprises biobased polyethylene in an amount of at least 40 percent, and preferably less than 90 percent, by weight of the core layer.

[0065] 10. Decorative panel (1) according to any of the preceding clauses, wherein the polyethylene, preferably biobased polyethylene, of the matrix material is a fibre reinforced polyethylene, wherein the fibers are for instance wood fibers.

[0066] 11 . Decorative panel (1 ) according to any of the preceding clauses, wherein said matrix material comprises at least one inert filler, such as calcium carbonate particles and / or wood particles, such as wood fibres, preferably in an amount of between 35 and 45 percent by weight of the matrix material. 12. Decorative panel (1) according to any of the preceding clauses, wherein said polymeric matrix material has a melt flow index of between 2 and 10, preferably between 4 and 8, g / 10min under the application of a standard weight of 5 kg and a temperature of 190 degrees Celsius, preferably according to ASTM D1238.

[0067] 13. Decorative panel (1) according to any of the preceding clauses, wherein a majority, preferably at least 90 percent, of said cork particles has a diameter smaller than 1 mm.

[0068] 14. Decorative panel (1) according to any of the preceding clauses, wherein at least 90 percent of said cork particles has a particle size capable of passing through a sieve with an aperture size of 1 mm.

[0069] 15. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises cork particles in an amount of at least 20 percent by volume of the core layer.

[0070] 16. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises cork particles in an amount of between 3 and 10 percent, preferably between 4 and 6 percent, such as 5 percent, by weight of the core layer.

[0071] 17. Decorative panel (1) according to any of the preceding clauses, wherein the average specific weight of the cork particles in the core layer is situated between 110 and 130 kg / m3.

[0072] 18. Decorative panel (1) according to any of the preceding clauses, wherein the cork particles are natural cork particles.

[0073] 19. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises at least one silicate formed by at least one bentonite, preferably sodium bentonite, in particular activated sodium bentonite.

[0074] 20. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises at least one silicate, preferably at least one bentonite, chosen from the group consisting of: montmorillonite, quartz dolomite, feldspar, and mixtures of two or more of these silicates.

[0075] 21 . Decorative panel (1 ) according to any of the preceding clauses, wherein the core layer comprises at least one silicate, wherein the total amount of silicate in the core layer is situated between 5 and 15 percent by weight of the core layer.

[0076] 22. Decorative panel (1) according to any of the preceding clauses, wherein the Young’s modulus of the core layer is at least 1 ,000 MPa, preferably at least 1 ,200 MPa.

[0077] 23. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises at least one silicate, wherein said silicate is substantially entirely encapsulated by the matrix material.

[0078] 24. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises at least one silicate, and wherein the core layer is free of waste slag.

[0079] 25. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises waste slag, and wherein the core layer is free of silicate.

[0080] 26. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises waste slag obtained from the incineration of solid waste incineration, preferably municipal solid waste incineration.

[0081] 27. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises waste slag, wherein the amount of waste slag in the core layer is situated between 10 and 30 percent by weight of the core layer.

[0082] 28. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises waste slag substantially free of heavy metals. 29. Decorative panel (1) according to any of the preceding clauses, wherein the core layer comprises waste slag comprising glass material, ceramic material, and sand.

[0083] 30. Decorative panel (1) according to any of the preceding clauses, wherein the matrix material of the core layer comprises recycled polypropylene and / or biobased polypropylene.

[0084] 31 . Decorative panel (1 ) according to any of the preceding clauses, wherein the core layer comprises at least one oil, preferably a natural fatty oil, such as soya oil, preferably an in amount of between 1 and 3 percent by weight of the core layer, and / or at least one organic substance or constituent chosen from the group consisting of: an unsaturated hydrocarbon; at least one triglyceride, preferably at least one triglyceride composed of glycerol and at least one fatty acid; and mixtures of two or more of these substances.

[0085] 32. Decorative panel (1) according to any of the preceding clauses, wherein the core layer further comprises a binding agent for binding the components of the core layer, wherein said binding agent is preferably a water based resin (EVA) and / or a natural binding agent.

[0086] 33. Decorative panel (1) according to any of the preceding clauses, wherein the decorative top structure comprises at least one decorative layer, and preferably at least one protective layer covering said decorative layer.

[0087] 34. Decorative panel (1) according to clause 33, wherein the decorative layer is formed by a printed decorative layer, in particular a digitally printed decorative layer, or by a veneer layer, or by a decorative film.

[0088] 35. Decorative panel (1) according to clause 33 or 34, wherein a top surface of the decorative top structure is provided with a relief pattern, wherein said relief pattern is preferably aligned with a decorative image of the decorative layer.

[0089] 36. Decorative panel (1) according to any of the preceding clauses, wherein the panel comprises a backing layer attached, directly or indirectly, to a bottom surface of the core layer, wherein the backing layer is preferably a cork based backing layer, preferably at least partially composed of a mixture of a polymeric material and cork particles.

[0090] 37. Decorative panel (1) according to any of the preceding clauses, wherein the panel comprises an intermediate layer situated in between the decorative top structure and the core layer, wherein the intermediate layer is a cork based intermediate layer, preferably at least partially composed of a mixture of a polymeric material and cork particles.

[0091] 38. Decorative panel (1) according to any of the preceding clauses, wherein the panel comprises at at least one pair of opposing side edges complementary coupling profiles allowing intercoupling of adjacent decorative panels.

[0092] 39. Decorative panel (1) according to any of the preceding clauses, wherein the inorganic fraction of the at least one filler is dispersed as particles in the polymer matrix.

[0093] 40. Decorative panel (1) according to any of the preceding clauses, wherein the inorganic fraction of the at least one filler is dispersed as particles in the polymer matrix and is formed by inorganic greenware particles.

[0094] 41 . Decorative panel (1 ) according to any of the preceding clauses, wherein the greenware particles comprises at least one further inorganic non-metallic constituent, in addition to said at least one silicate and alumina, wherein said at least one further inorganic non-metallic constituent is preferably chosen from the group consisting of: zirconium oxide, bismuth oxide, magnesium oxide, barium titanate, cordierite, boron nitride, tungsten carbide, tantalum carbide, titanium carbide, niobium carbide, zirconium carbide, boron carbide, hafnium carbide, silicon carbide, niobium boron carbide, aluminium nitride, titanium nitride, zirconium nitride, tantalum nitride, hafnium nitride, niobium nitride, boron nitride, silicon nitride, titanium boride, chromium boride, zirconium boride, tantalum boride, molybdenum boride, tungsten boride, cerium sulphide, titanium sulphide, magnesium sulphide, zirconium sulphide and mixtures and alloys of these. 42. Decorative panel (1) according to any of the preceding clauses, wherein the weight ratio silicate to alumina in the inorganic fraction is at least 3, preferably at least 3.5, and optionally less than 4.

[0095] 43. Decorative panel (1) according to any of the preceding clauses, wherein the inorganic fraction of the at least one filler is dispersed as particles in the polymer matrix, wherein at least 25 weight percent of the particles has a diameter larger than 180 micron, and / or wherein at least wherein at least 20 weight percent of the particles has a diameter larger than 250 micron, and / or wherein at least 10 weight percent of the particles has a diameter larger than 500 micron.

[0096] 44. Decorative panel (1) according to any of the preceding clauses, wherein the wherein inorganic fraction of the filler is present in the core layer (2) in an amount of between 15 and 40 percent, preferably between 18 and 30 percent, such as between 20 and 25 percent, by weight of the core layer.

[0097] 45. Core layer for use in a decorative panel according to any of the preceding clauses.

[0098] 46. Method of producing a decorative panel (1), in particular a panel according to any of the preceding clauses, comprising the steps of: a) Providing and mixing: i. a matrix material at least partially composed of recycled polyethylene and / or biobased polyethylene; ii. cork particles; and iii. at least one filler, wherein said filler is at least one filler chosen from the group consisting of: a silicate and waste slag; b) shaping, in particular moulding and / or extruding, said mixture created during step a) to form a core layer; and c) affixing, directly or indirectly, a decorative top structure on top of said core layer.

[0099] 47. Method according to clause 46, wherein during step a) the materials to be mixed are heated, for example to temperatures in the range of 150° C to 220° C. 48. Method according to clause 46 or 47, wherein during step a) the material are mixed for a period of time between 300 and 600 seconds.

[0100] 49. Method according to one of clauses 46-48, wherein step b) takes place at elevated temperature exceeding the softening temperature of said recycled polyethylene and / or biobased polyethylene, and for a period of time which is preferably situated in between 1 and 3 hours.

[0101] 50. Method according to one of clauses 46-49, wherein step c) is carried out after cooling of the core layer to a temperature below said softening temperature and above room temperature.

[0102] 51 . Method according to one of clauses 46-50, wherein during step c) at least one intermediate layer, preferably intermediate cork-based layer, is applied onto the top surface of the core layer, wherein the decorative top structure is applied onto the top surface of the intermediate layer.

[0103] 52. Method according to one of clauses 46-51 , wherein the method comprises step d), wherein during step d) at least one backing layer, preferably cork based backing layer, is applied, directly or indirectly, to the bottom surface of the core layer.

[0104] 53. Method according to one of clauses 46-52, wherein the method comprises step e), performed after step c), relating to profiling of at least one pair of opposite side edges of the decorative panel to realize complementary coupling profiles allowing interlocking of adjacent decorative panels.

[0105] The invention will be elucidated on the basis of non-limitative exemplary embodiments shown in the following figures. Herein:

[0106] Figure 1 schematically shows a decorative panel according to the invention; Figure 2 shows the panel of figure 1 without the optional intermediate layer; Figures 3 and 4 schematically show possible configurations of complementary coupling profiles according to the invention;

[0107] Figures 5 and 6 schematically show other possible coupling profiles according to the present invention; Figure 7 schematically shows a decorative panel according to the invention; and

[0108] Figure 8 shows a non-limitative embodiment of the method according to the invention.

[0109] Figure 1 schematically shows a panel (1) according to the invention, with a centrally located core layer (2), wherein said core layer (2) comprises an top surface (3) and a bottom surface (4), preferably on opposite sides of said core. A backing layer (5) is in this non-limitative embodiment attached to the bottom surface (4) of the core. The backing layer may be at least partially composed out of cork based material, preferably a mixture of polymeric material and cork particles. This may contribute to damping properties of the panel (1). Figure 1 also shows a decorative top structure (6), which is attached to the top surface (3) of the core (2). Although the decorative top structure (6) is indicated as a single layer in this non-limitative embodiment, it is conceivable that the decorative top structure (6) comprises more than one layer. For example, the decorative top structure (6) may be formed by; a printed decorative layer, such as a digital print layer, veneer layer, or decorative film, an embossing structure or pattern layer, which may form a relief of the panel, and optionally a wear or protective layer.

[0110] On two opposite sides (7, 8) of the panel (1), which may alternatively be referred to as a pair of opposing edges (7, 8), complementary coupling parts (9, 10) are provided. The first coupling part (7) is in the form of a downward tongue (11) and the second coupling part (9) is in the form of an upward tongue (12). The second coupling part (9) may comprise a single upward tongue (12), at least one upward flank (13) lying at a distance from the upward tongue and a single upward groove (14) formed between the upward tongue and the upward flank, wherein at least a part of a side (15) of the upward tongue facing toward the upward flank is inclined and extends in the direction of the normal (N1) of the upper side or top surface (3) of the core, and wherein optionally at least a part of a side (16) of the upward tongue facing away from the upward flank comprises a substantially rigid first locking element (17), and on a second or fourth edge, a single downward tongue (11), at least one downward flank (18) lying at a distance from the downward tongue, and a single downward groove (19) formed between the downward tongue and the downward flank, wherein at least a part of a side (20) of the downward tongue facing toward the downward flank is inclined and extends in the direction of the normal (N2) of the lower side or bottom surface (4) of the core, and wherein the downward flank optionally comprises a, preferably substantially rigid, second locking element (21) adapted for co-action with the first locking element of a third edge of yet a further panel.

[0111] Figure 1 further shows that an upper or front side (22) of the upward tongue (12) is inclined, from a top side (22A) downwards towards the outside (16). The transition from the inside (15) of the upward tongue (12) to the top side (22A) forms an aligning edge (23). A similar construction is present on the other side, with an upper side (24) of the groove (19) being inclined. The aligning edge (25) on the downward tongue (11) is arranged on the outside (26) thereof. On both sides, the transition between the tongue (11 , 12) and the core (2) is formed by a bridge, being an upper bridge (27) on the downward tongue (11) side and a lower bridge (28) on the upward tongue (12) side. The transition (29) from the downward tongue (11) towards the inside thereof is shown rounded, to facilitate deformation.

[0112] Figure 1 further shows that between the centrally located core layer (2) and the decorative top structure (6) an optional intermediate layer (30) is arranged, which layer is absent in figure 2. The intermediate layer (30) may, for example, act as balancing layer and / or sound dampening layer and / or comfort layer. The intermediate layer (30) may also be at least partially cork based. Preferably, said intermediate layer (30) is at least partially composed of a mixture of a polymeric material and cork particles.

[0113] The core layer (2) as shown in figure 1 is at least partially composed of a matrix material. Said matrix material comprising at least a portion of recycled polyethylene and / or biobased polyethylene. Yet, it may also be conceivable that instead or in addition to the aforementioned polyethylene materials, alternative recycled and / or biobased polymer materials may be provided in the matrix material. However, it is preferred that the core layer (2) is free of fossil-based polymer material, which contributes to the reduction of the carbon footprint of the panel (1) according to the invention. The biobased polymer material may be obtained for example from sugar cane, sugar beet, palm oil, and / or wheat grain. It is conceivable that the biobased polymer, in particular biobased polyethylene, is made out of dehydrated bio- ethanol. Said biobased polyethylene, or the biobased polymer in general, may be at least partially fibre reinforced, said fibers may for example be wood fibers or the like. Cork particles may be dispersed or provided in the material matrix. Said cork particles may contribute to a lightweight panel (1). The amount of cork particles dispersed within the material matrix may be up to 55 percent by volume of the core layer (1). However, since the density of cork is relatively low, this volumetric amount of cork in the core layer (1) preferably contributes up to at about 3 percent to 10 percent of cork by weight of the core layer. In respect of the matrix material, particles may be understood in a broad sense. That is, the cork particles may differ in size, but preferably have a maximum size of about 1 .0 mm. This may allow the cork particles to be uniformly distributed throughout the material matrix. In addition to the abovementioned materials of the matrix, it is conceivable that at least one filler is provided in said material matrix, said filler comprising at least one constituent preferably being chosen from at least one silicate, alumina (AI2O3), greenware particles, (waste) slag, in particular a purified (waste) slag, and mixtures of two or more of these (inorganic) fillers. However, additionally or alternatively one or more other fillers may be present in the core layer, such as an inert filler, for example calcium carbonate (limestone) particles, and / or talc and / or glass particles; and / or wood particles (e.g., fibers); and / or one or more other natural or synthetic fillers. . In the case of a (waste) slag, it may be conceivable that said waste slag is obtained at least partially from incineration of (solid) waste incineration, such as municipal solid waste incineration. It is desired to purify the slag at some point, to filter heavy metals from the material. If the type of filler is a silicate, this silicate may at least partially be formed by at least one bentonite, such as sodium bentonite, montmorillonite, quartz dolomite, and / or feldspar, the latter may even be activated. The filler may contribute to the overall stiffness of the panel (1), Which panel, or at least the core layer (1) may have a Young’s modulus of at least 1 ,000 MPa, preferably at least 1 ,200 MPa. In an embodiment the composition of the core layer may comprise 5-6 percent cork particles, and / or 70-75 percent recycled PE, preferably recycled HDPE, and / or 18-25 percent greenware particles, and / or 0.5-3 percent soya oil, wherein said weight percentages are in relation to the weight of the core layer. Figures 3 and 4 show possible other configurations of the complementary coupling parts and may also be usable for the invention as possible embodiments for the sideward tongue and groove combination.

[0114] Figure 3 for example shows on a first edge a sideward tongue (32) extending in a direction substantially parallel to the top surface (3) of the panel, the bottom front region (33) of said sideward tongue being rounded at least partly, the bottom back region (24) of said tongue being configured as bearing region, wherein the bottom back region (24) is located closer to the level of the top surface (3) of the panel than a lowest part of the bottom front region, and on an opposite second edge (8) comprising a recess or sideward groove (35) for accommodating at least a part of the sideward tongue of a further panel, said recess being defined by an upper lip (36) and a lower lip (37), said lower lip being provided with a upwardly protruding shoulder (38) for supporting and / or facing the bearing region of the sideward tongue.

[0115] Figures 4a-4e show various variations on shapes usable for sideward tongues and grooves according to the present invention.

[0116] Figures 5 and 6 shows possible other configurations of the complementary coupling parts configurations and may also be usable for the invention as possible embodiments for the downward and upward tongue combination. In figure 5 a similar locking system is shown compared to figures 1 and 2, with a slightly different shaping as well as with additional locking (31) on the outside of the downward tongue (11) and the upper side of the upward flank (13). In figure 6 the locking is shown as an open groove, wherein the insides (15, 20) of the tongues (11 , 12) are inclined, but not towards the cores but away from the cores. The angle of those insides (15, 20) is opposite to the one shown in figures 1 and 2.

[0117] Figure 7 schematically shows a decorative panel (1) with a top surface (3) and a Sidebottom surface (4) on opposite sides of the core. The panel (1) is rectangular with four edges. The opposite edges (7, 8) on the short sides and two opposite edges (7’, 8’) on the short sides. Along the cross section A-A in figure 7 the coupling parts on the long sides would show up, represented for example by the figures 3 and 4. Along the cross section B-B the coupling parts on the short sides would be shown, represented by the other figures of the application. The core layer (not indicated) of the decorative panel (1) may be the same as the core layer (2) described with respect to figure 1 . However, it is also conceivable that the composition is slightly different, and therefore does not necessarily have to be identical throughout different embodiments. One skilled in the art may for example decide on a specific polymeric material that is used for the matrix material or decide on an amount of cork particles that is dispersed, or the type of filler that is used.

[0118] Figure 8 shows a non-limitative embodiment of the method 100 according to the present invention. The method 100 in the embodiment depicted comprises a first step (101), which relates to providing and mixing (101) materials, here a total of three materials (104, 105, 106) are provided and mixed (101). A primary provided material (104) may be a matrix material, which is a at least partially composed of recycled polyethylene and / or biobased polyethylene. The second material (105) may be a portion of cork particles (105). Said cork particles (105) may contribute to for example about 35 percent by volume of the core material. A third material (106) that is provided and mixed (101) may be at least one filler. Sai filler may be chosen from the group of a silicate (106) and waste slag (106). During the initial step (101) the materials (104, 105, 106) may be heated and mixed at a temperature of about 150° C to 220° C. Mixing at elevated temperature may take place for a period of 300 to 600 seconds. In order to pursue qualitative product properties, it may be desired to control the mixing process of the initial step (101). To this end, a control unit (107) may be provided for controlling properties of the mixing process. During the mixing, the control unit (107) may communicate (108) with the mixing process, in particular exchanging information, for example based on one or more sensors, such as temperature sensors. After providing and mixing (101) the cork particles may be dispersed within the (still at least partially liquid) core material. Said cork particles may be homogeneously dispersed. During a second step (102) the (still at least partially liquid) core material may be shaped (102). Here shaping (102) may be understood as moulding and / or extruding the material mixed during the previous step (101) to form a core layer. After the core layer is moulded and formed (102), a decorative top structure may be affixed (103). Said top structure may be affixed directly or indirectly on a top surface of the moulded core layer formed during the previous step (102). Prior to affixing (103) the decorative top structure, it is optionally possible to affix (109) an intermediate layer. Said intermediate layer is affixed (109) preferably onto the top surface of the core that is moulded (102). The decorative top structure may in case of an intermediate layer be affixed (103) onto the top surface of the intermediate layer. The embodiment shown in figure 8 further comprises a step (110) of providing a backing layer, which may be cork based, onto a bottom surface of the core layer. In this embodiment, the backing layer is provided after application of the decorative top structure and the optional intermediate layer. However, alternatively it is possible to provide (110) the backing layer prior to affixing the optional intermediate layer (109) and decorative top structure (103). It is furthermore possible that after the second step (102) the core layer is partially cured, and that a profiling step (not shown) is performed. The profiling step may relate to profiling at least one pair of opposite side edges of the core layer of the decorative panel to provide complementary coupling profiles. Said profiles may allow for interlocking of adjacent decorative panels.

[0119] 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.

[0120] The ordinal numbers used in this document, like “first”, “second”, “third” and “fourth”, are used only for identification purposes. Hence, the use of the expression “third coupling profile” does therefore not necessarily require the co-presence of a “first coupling profile”. And likewise, the use of the expressions “third locking element” and “second locking element” does therefore not necessarily require the co-presence of a “first locking element”. By "horizontal", it is meant as a direction which extends parallel to a plane defined by the tile panel, and which may intersect a core layer of the tile panel. By “vertical”, it is meant as a direction which is perpendicular to said plane defined by the tile panel. By "complementary" coupling profiles, it is meant that these coupling profiles of adjacent tile panels can cooperate with each other. However, to this end, the complementary coupling profiles do not necessarily have to have fully complementary forms (inverted designs). By “proximal side”, it is meant a side which is positioned closest to a body of the tile panel, while by “distal side”, it is meant as a side which is positioned farther from a body of the tile panel than said proximal side. The proximal side may face said tile panel body, while the distal side may face away from said tile panel body.

[0121] In the above, the expression “polyethylene” may be replaced by at least one other thermoplastic polyolefin, such as polypropylene, and / or at least one thermoplastic polyester, such as polyester terephthalate, and / or at least one other thermoplastic, preferably chloride-free, polymer, and mixtures thereof.

[0122] 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

Claims1. Decorative panel (1 ), in particular a floor panel, a wall panel, or a ceiling panel, comprising:• a core layer (2); and• a decorative top structure (6) directly or indirectly affixed to a top surface of said core layer (2), wherein said core layer (2) is at least partially composed of:• a matrix material at least partially composed of recycled polyethylene and / or biobased polyethylene;• cork particles dispersed in said matrix material; and at least one filler dispersed in said matrix material, wherein said filler comprises an inorganic fraction, wherein said inorganic fraction comprises at least one silicate, in particular quartz (SiO2), and alumina (AI2O3), wherein the core layer (2) comprises cork particles in an amount of between 3 and 10 percent, preferably between 4 and 6 percent, such as 5 percent, by weight of the core layer.

2. Decorative panel (1) according to claim 1 , wherein said core layer (2) is free of virgin fossil-based polymers.

3. Decorative panel (1) according to claim 1 or 2, wherein said core layer (2) is free of polyvinyl chloride.

4. Decorative panel (1) according to any of the preceding claims, wherein said matrix material is at least partially, preferably entirely composed of recycled high density polyethylene (HDPE).

5. Decorative panel (1) according to any of the preceding claims, wherein said matrix material is at least partially, preferably entirely composed of biobased polyethylene, wherein said biobased polyethylene is plant-based polyethylene, in particular obtained from sugar cane, sugar beet, palm oil, and / or wheat grain.

6. Decorative panel (1) according to any of the preceding claims, wherein said matrix material is at least partially, preferably entirely composed of biobased polyethylene made out of dehydrated bio-ethanol.

7. Decorative panel (1) according to any of the preceding claims, wherein said core layer comprises recycled polyethylene and / or biobased polyethylene in an amount of at least 35 percent by weight of the core layer.

8. Decorative panel (1) according to any of the preceding claims, wherein said core layer comprises recycled polyethylene in an amount of at least 35 percent, and preferably less than 55 percent, by weight of the core layer.

9. Decorative panel (1) according to any of the preceding claims, wherein said core layer comprises biobased polyethylene in an amount of at least 40 percent, and preferably less than 90 percent, by weight of the core layer.

10. Decorative panel (1) according to any of the preceding claims, wherein the polyethylene, preferably biobased polyethylene, of the matrix material is a fibre reinforced polyethylene, wherein the fibers are for instance wood fibers.11 . Decorative panel (1 ) according to any of the preceding claims, wherein said matrix material comprises at least one inert filler, such as calcium carbonate particles and / or wood particles, such as wood fibres, preferably in an amount of between 35 and 45 percent by weight of the matrix material.

12. Decorative panel (1) according to any of the preceding claims, wherein said polymeric matrix material has a melt flow index of between 2 and 10, preferably between 4 and 8, g / 10min under the application of a standard weight of 5 kg and a temperature of 190 degrees Celsius, preferably according to ASTM D1238.

13. Decorative panel (1) according to any of the preceding claims, wherein a majority, preferably at least 90 percent, of said cork particles has a diameter smaller than 1 mm.

14. Decorative panel (1) according to any of the preceding claims, wherein at least 90 percent of said cork particles has a particle size capable of passing through a sieve with an aperture size of 1 mm.

15. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises cork particles in an amount of at least 20 percent by volume of the core layer.

16. Decorative panel (1) according to any of the preceding claims, wherein the average specific weight of the cork particles in the core layer is situated between 110 and 130 kg / m3.

17. Decorative panel (1) according to any of the preceding claims, wherein the cork particles are natural cork particles.

18. Decorative panel (1) according to any of the preceding claims, wherein the wherein inorganic fraction of the filler is present in the core layer (2) in an amount of between 15 and 40 percent, preferably between 18 and 30 percent, such as between 20 and 25 percent, by weight of the core layer.

19. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises at least one silicate formed by at least one bentonite, preferably sodium bentonite, in particular activated sodium bentonite.

20. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises at least one silicate, preferably at least one bentonite, chosen from the group consisting of: montmorillonita, quartz dolomite, feldspar, and mixtures of two or more of these silicates.21 . Decorative panel (1 ) according to any of the preceding claims, wherein the core layer comprises at least one silicate, wherein the total amount of silicate in the core layer is situated between 5 and 15 percent by weight of the core layer.

22. Decorative panel (1) according to any of the preceding claims, wherein the Young’s modulus of the core layer is at least 1 ,000 MPa, preferably at least 1 ,200 MPa.

23. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises at least one silicate, wherein said silicate is substantially entirely encapsulated by the matrix material.

24. Decorative panel (1) according to any of the preceding claims, wherein the core layer is free of waste slag.

25. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises waste slag.

26. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises waste slag obtained from the incineration of solid waste incineration, preferably municipal solid waste incineration.

27. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises waste slag, wherein the amount of waste slag in the core layer is situated between 10 and 30 percent by weight of the core layer.

28. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises waste slag substantially free of heavy metals.

29. Decorative panel (1) according to any of the preceding claims, wherein the core layer comprises waste slag comprising glass material, ceramic material, and sand.

30. Decorative panel (1) according to any of the preceding claims, wherein the matrix material of the core layer comprises recycled polypropylene and / or biobased polypropylene.31 . Decorative panel (1 ) according to any of the preceding claims, wherein the core layer comprises at least one oil, preferably a natural fatty oil, such as soya oil, preferably an in amount of between 1 and 3 percent by weight of the core layer.

32. Decorative panel (1) according to any of the preceding claims, wherein the core layer further comprises a binding agent for binding the components of the corelayer, wherein said binding agent is preferably a water based resin (EVA) and / or a natural binding agent.

33. Decorative panel (1) according to any of the preceding claims, wherein the decorative top structure comprises at least one decorative layer, and preferably at least one protective layer covering said decorative layer.

34. Decorative panel (1) according to claim 33, wherein the decorative layer is formed by a printed decorative layer, in particular a digitally printed decorative layer, or by a veneer layer, or by a decorative film.

35. Decorative panel (1) according to claim 33 or 34, wherein a top surface of the decorative top structure is provided with a relief pattern, wherein said relief pattern is preferably aligned with a decorative image of the decorative layer.

36. Decorative panel (1) according to any of the preceding claims, wherein the panel comprises a backing layer attached, directly or indirectly, to a bottom surface of the core layer, wherein the backing layer is preferably a cork based backing layer, preferably at least partially composed of a mixture of a polymeric material and cork particles.

37. Decorative panel (1) according to any of the preceding claims, wherein the panel comprises an intermediate layer situated in between the decorative top structure and the core layer, wherein the intermediate layer is a cork based intermediate layer, preferably at least partially composed of a mixture of a polymeric material and cork particles.

38. Decorative panel (1) according to any of the preceding claims, wherein the panel comprises at at least one pair of opposing side edges complementary coupling profiles allowing intercoupling of adjacent decorative panels.

39. Decorative panel (1) according to any of the preceding claims, wherein the inorganic fraction of the at least one filler is dispersed as particles in the polymer matrix.

40. Decorative panel (1) according to any of the preceding claims, wherein the inorganic fraction of the at least one filler is dispersed as particles in the polymer matrix and is formed by inorganic greenware particles.41 . Decorative panel (1 ) according to any of the preceding claims, wherein the greenware particles comprises at least one further inorganic non-metallic constituent, in addition to said at least one silicate and alumina, wherein said at least one further inorganic non-metallic constituent is preferably chosen from the group consisting of: zirconium oxide, bismuth oxide, magnesium oxide, barium titanate, cordierite, boron nitride, tungsten carbide, tantalum carbide, titanium carbide, niobium carbide, zirconium carbide, boron carbide, hafnium carbide, silicon carbide, niobium boron carbide, aluminium nitride, titanium nitride, zirconium nitride, tantalum nitride, hafnium nitride, niobium nitride, boron nitride, silicon nitride, titanium boride, chromium boride, zirconium boride, tantalum boride, molybdenum boride, tungsten boride, cerium sulphide, titanium sulphide, magnesium sulphide, zirconium sulphide and mixtures and alloys of these.

42. Decorative panel (1) according to any of the preceding claims, wherein the weight ratio silicate to alumina in the inorganic fraction is at least 3, preferably at least 3.5, and optionally less than 4.

43. Decorative panel (1) according to any of the preceding claims, wherein the inorganic fraction of the at least one filler is dispersed as particles in the polymer matrix, wherein at least 25 weight percent of the particles has a diameter larger than 180 micron, and / or wherein at least wherein at least 20 weight percent of the particles has a diameter larger than 250 micron, and / or wherein at least 10 weight percent of the particles has a diameter larger than 500 micron.

44. Core layer for use in a decorative panel according to any of the preceding claims.

45. Method of producing a decorative panel (1), in particular a panel according to any of the preceding claims, comprising the steps of: a) Providing and mixing:i. a matrix material at least partially composed of recycled polyethylene and / or biobased polyethylene; ii. cork particles in an amount of between 3 and 10 percent, preferably between 4 and 6 percent, such as 5 percent, by weight of the core layer; and iii. at least one filler, wherein said filler comprises an inorganic fraction, wherein said inorganic fraction comprises at least one silicate, in particular quartz (SiO2), and alumina (AI2O3),; b) shaping, in particular moulding and / or extruding, said mixture created during step a) to form a core layer; and c) affixing, directly or indirectly, a decorative top structure on top of said core layer.

46. Method according to claim 45, wherein during step a) the materials to be mixed are heated, for example to temperatures in the range of 150° C to 220° C.

47. Method according to claim 45 or 46, wherein during step a) the material are mixed for a period of time between 300 and 600 seconds.

48. Method according to one of claims 45-47, wherein step b) takes place at elevated temperature exceeding the softening temperature of said recycled polyethylene and / or biobased polyethylene, and for a period of time which is preferably situated in between 1 and 3 hours.

49. Method according to one of claims 45-48, wherein step c) is carried out after cooling of the core layer to a temperature below said softening temperature and above room temperature.

50. Method according to one of claims 45-49, wherein during step c) at least one intermediate layer, preferably intermediate cork-based layer, is applied onto the top surface of the core layer, wherein the decorative top structure is applied onto the top surface of the intermediate layer.51 . Method according to one of claims 45-50, wherein the method comprises step d), wherein during step d) at least one backing layer, preferably cork basedbacking layer, is applied, directly or indirectly, to the bottom surface of the core layer.

52. Method according to one of claims 45-51 , wherein the method comprises step e), performed after step c), relating to profiling of at least one pair of opposite side edges of the decorative panel to realize complementary coupling profiles allowing interlocking of adjacent decorative panels.

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