The present invention relates to an extruded panel and to a method for manufacturing such a panel. The invention relates to particularly a floor panel, a ceiling panel, or a wall panel produced by means of extrusion, comprising at least a channel formed by means of extrusion, tongue-and-groove coupling profiles on at least two opposite edges of the panel wherein said coupling profiles are integrated with its core material. The invention also relates to a panel covering, such as a floor covering or wall covering composed of a plurality of interlocked panels according to the invention.

Over the years, it has been known that the panel industry has been growing vastly. Floor panel installation, for example, has been acknowledged in enormous ways. The installation methods and materials being used vary depending on whether it is for indoor and/or outdoor use. The use of wood as a core material for indoor and/or outdoor panels is more costly and hard to maintain. The use of synthetic material is cheaper, however, it leads to less environmentally friendly manufacturing. The use of composite material as a core material of a panel has been properly acquainted especially in recent years because it is resistant to weather, cost-effective, and more environmentally friendly. Some installation techniques are considered complicated as it is known to install floor panels by gluing or nailing onto the underlying floor, which also makes it more difficult to break the installed floor panels. According to the proposed invention, the floor panels are able to be installed loosely onto the subflooring or a supporting structure, whereby the floor panels mutually match each other by means of a tongue and groove coupling. A floor obtained in this manner is also called a floating floor, which has the advantage that it is not difficult to install and that the complete surface can conveniently move which often is practical in order to receive possible expansion and shrinkage phenomena due to changes in weather, temperature, humidity, and so on.

It is the goal of the invention to overcome these disadvantages and provide a rather lightweight, more environmentally friendly, more cost-effective panel that has relatively effective coupling profiles to interlock both in horizontal and vertical directions. A further goal is to also provide a panel formed by means of extrusion comprising at least a channel in the core of the panel and at least a portion of the coupling profiles is made also by means of extrusion, that is scalable to manufacture, needs relatively low maintenance, while does not influence the strength and quality of the said panel.

To that end, the invention proposed a panel, in particular a floor panel, a ceiling panel, or a wall panel, comprising:

• an extruded core provided with an upper side and a lower side on opposite sides of the core, wherein the core comprises at least an extruded polymer material,

• coupling profiles arranged on at least two opposite edges of said core, wherein the coupling profiles are preferably integrated with the core, wherein said coupling profiles are designed to interlock with coupling profiles of an adjacent panel with tongue and groove coupling profiles in a horizontal direction and/or in a vertical direction, preferably in both directions, and

• wherein the core comprises at least one channel, extending along an extrusion direction, wherein the at least one channel is arranged at a distance from the lower side and/or the upper side.

The panel according to the invention has several advantages. A first advantage is that the weight of the panel per m ² of its top surface is relatively low, leading to a lightweight panel, which is beneficiary from an economic, environmental, and logistic point of view. The relatively low weight of the panel is realized by applying at least one channel by means of extrusion, extending along an extrusion direction, wherein the at least one channel is arranged at a distance from the lower side and/or the upper side of the panel, which reduces the amount of material used in the core and therefore in the panel as such.

Preferably the channels are located at a distance from at least two panel edges, and more preferably at a distance from coupling profiles located at said panel edges. In this manner the coupling profiles are not weakened by the channel(s), as a result of which the coupling profiles can be shaped in a relatively robust (unweakened) manner. Preferably, the panel is an oblong panel, more preferably an oblong, rectangular panel. This oblong panel typically comprises two longitudinal edges and two transverse edges. During production of the panel, the extrusion direction typically, but not necessarily, runs parallel to the longitudinal edges. This latter allows the form (shape) at least a part of the coupling profiles located at the longitudinal edges of the panel during the extrusion process. It is also possible that coupling profiles are located at the transverse edges (often short edges) of the panel. It is possible that all sides of the panel are provided with coupling profiles. It is preferred that coupling profiles located at opposite panel edges are shaped in a complementary manner allowing said pair of complementary coupling profiles of adjacent panels to co-act with each other. It is possible that the panel is square or has another polygonal shapes, such as triangular, hexagonal or octagonal shapes or parallelogrammatic shapes.

Preferably, the method to produce such panel is realised by extrusion. This is an additional advantage to not forming the panel in a mechanical manner, for example by means of milling, therefore it does not lead to an undesired generation of dust particles during the formation of the panel. Such dust particles not only pollute the production environment and the core as such, and therefore the panel as such, but also lead to unwanted health risks for production employees. Furthermore, extrusion, instead of milling, also leads to less material waste, which is beneficiary from an environmental and economical point of view. It is likewise relatively more efficient and economical for the panel manufacturers to produce a mass scale of these panels. The panel according to the invention may be used as an indoor (interior) panel and/or as an outdoor (exterior) panel.

The panels according to the invention are typically elongated, wherein the profiles with the coupling profiles along the long sides of the panels are formed by extrusion and are formed along the extrusion direction. The extrusion direction may thus also be the longitudinal direction of the panel. During the extrusion process the shapes of the long sides of the panels are formed, wherein the short sides are typically not profiled during the extrusion process. The short sides may for instance be profiled by milling after extrusion, or may remain unprofiled and be only cut to the desired length of panel.

With a horizontal direction and in a vertical direction may also be meant a direction in the plane of the panel (for flooring or ceiling panels being horizontal, for wall panels being vertical) and a direction perpendicular to that plane (for flooring or ceiling panels being vertical, for wall panels being horizontal).

The coupling profiles at opposite panel edge are preferably complementary, and are often configured to realized at least one tongue-groove connection. Preferably, at least one pair of coupling profiles of the panel is configured to be coupled by means of an angling or rotational movement. In such movement a tongue of a first coupling profile of one panel is placed, at an angle, into a groove of a second coupling profile of an adjacent panel, followed by an angular motion to finish coupling of two panels. Such coupling systems have been around in traditional (wooden) flooring for a long time and provide an intuitive coupling method for coupling the panels.

The core according to the invention may comprise extrudable polymer material, wherein, preferably, the core comprises a composite comprising at least one polymer, in particular, a thermoplastic material and/or a thermoset material, and at least one non-polymeric material. Examples of such extrudable polymeric materials are, but are not limited to, ethylene-vinyl acetate (EVA), which is a copolymer of ethylene and vinyl acetate, rubber, polyurethane (PU), in particular thermoplastic polyurethane (TPU), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinylchloride (PVC), polyethylene terephthalate (PET), or mixtures thereof. Also in case another thermoplastic material is used, this material may be applied in a foamed state in the core to reduce the density and costs. For example, PS may be in the form of expanded PS (EPS) in order to further reduce the density of the panel, which leads to a saving in costs and facilitates handling of the panels. Nevertheless, it is also imaginable that the thermoplastic material used as the main polymer is a solid polymer (i.e. an unfoamed polymer). Preferably, at least a fraction of the polymer used may be formed by recycled thermoplastic, such as recycled PVC and/or recycled TPU, and/or recycled PET. It is conceivable that a mix of virgin and recycled thermoplastic material is used to compose at least a part of the core. In a preferred embodiment, the core may comprise at least 20% of its weight of the thermoplastic material, preferably in between 20% up to 100% of its weight of the (recycled) thermoplastic material. The weight ratio between virgin thermoplastic material and recycled thermoplastic material is preferably less than 4 (i.e. at least 20% by weight is formed by recycled thermoplastic material). Instead of the thermoplastic material, a thermoset polymer may also be used, such as thermoset polyurethane. The core may comprise at least one plasticizer to increase the flexibility of the panel as such. The composite of the core layer preferably comprises one or more fillers, wherein such fillers are made of non-polymeric materials. Examples of such non-polymeric materials are but are not limited to, talc, chalk, wood, calcium carbonate, titanium dioxide, calcined clay, porcelain, glass particles, carbon particles, silicon particular, a(nother) mineral filler, a(nother) natural filler, cellulose-based particles, coconut, kevlar, nylon, perlon, rock wool, bamboo, sisal, fique, a(nother) (auxiliary) polymer, such as an elastomer and/or latex. It is also imaginable that rubber and/or elastomeric parts (particles) are dispersed within the composite to improve the flexibility and/or impact resistance at least to some extent. The core may (thus) be rigid, semi-flexible, or flexible, and so can be the floor covering element as such. The filler may be formed by fibres, such as glass fibres or synthetic or genuine leather fibres, and/or may be formed by dust-like particles. Here, the expression “dust” is understood as small dust-like particles (powder), like bamboo dust, wood dust, cork dust, or non-wood dust, like mineral dust, stone powder, in particular cement, and combinations thereof. The average particle size of the dust is preferably between 14 and 20 micron, more preferably between 16 and 18 micron. This may further increase the strength of the panel and/or the water resistivity and/or the fireproof properties of the panel as such, and/or may lower the cost price of the panel as such.

During the extrusion process, it is conceivable that the core is provided with at least two zones of different compositions. Such zones may be obtained, for example, by means of co-extrusion. The different compositions in different zones may result in mutually different features, such as, for example, in respect to elasticity, colour, adherence, smoothness of the surface, processability, and the like. It is aimed that different compositions in the core layer may lead to a better sound dampening effect of the panel, in combination with the extruded channels thereof, better acoustics of the area applied with such panels may be achieved. For example in an indoor and/or outdoor situation, the walking sound, but is not limited to, and any other sound may be absorbed better with said co-extruded core compositions. Different compositions in different zones may, for example, be based upon different ratios between polymeric material, in particular thermoplastic material (like PVC and/or PET), and non-polymeric material, in particular filler, more in particular mineral filler (like chalk). For example, to this end, it is imaginable that the core layer is relatively stiff or rigid, and the other layer, preferably positioned underneath the core layer during normal use, is relatively flexible or soft. It may be beneficial for the coupling profiles to have co-extrusion as the softer side of the core may increase flexibility, therefore less stress pressure during coupling which may result in more durable coupling profiles. Alternatively, when possible to be extruded, the core may be partially composed of another base material, such as a mineral material, like magnesium oxide, magnesium hydroxide, gypsum, (lightweight) concrete, and/or clay; and/or a wood or a wood-based material, such as HDF or MDF, or any other thermoplastic-free material, may be used as base material. In a preferred embodiment, the areal density of the core is less than 9000 g/m2, preferably less than 6000 g/m2, more preferably around 5000 g/m2.

Preferably, it is desirable that the panel comprises at least a channel or multiple channels, each surrounded at the top and bottom by at least one of the core material(s), wherein the volume of the at least one channel makes up preferably at least 20% of the volume of the core, more preferably between 30%-40% of the volume of the core. A channel in the present invention may refer to a hollow surrounded by core material(s), wherein said hollow is located in between the opposite sides comprising the coupling profiles and does not intersect with any coupling profiles. This is viable to maintain a decent rigidity and structural ability of the core, thus the panel is lightweight but still has high functionality and strength, thereby the cost can be reduced.

Preferably, at least one, more preferably each, channel connects (to) opposing side edges. This leads to channels with open end sections. This channels may not only lead to weight saving, but may also functionally be used, for example for drainage of water and/or for accommodating (electric) cables and/or wires. Hence, at least one channel may be provided with at least one cable and/or at least one wire. At least one cable and/or at least one wire may make integral part of the panel and/or may be fixated within at least one channel. It is imaginable that the channel(s) is/are entirely filled with cable material and/or wire material.

Desirably, when the panel comprises multiple channels, it is possible that one channel is located next to the other or on top of each other while comprising the same or different shapes with each other. In general, the hollowed core is one of the most sustainable products in construction and/or installation. It is also imaginable that at least one core groove is filled with at least one solid and/or liquid material. Preferably, this filling material is cheaper than the polymer and/or other ingredients (additives) used in the core. Examples of cheap filling materials are solid wood, wood chips, wood dust, wood fibre, hemp fibre, bamboo, and mineral fillers, such as chalk (calcium carbonate). By at least partially filling at least one core groove, and preferably all core grooves, the panel is provided different properties, such as for example an increased sound reduction.

It may be preferred that the core comprises a plurality of core layers. At least two of these core layers may have different compositions (as indicated above) and/or may have identical compositions. The core layers are laminated on top of each other. Preferably, such a multi-layered core is manufactured by means of co-extrusion and/or calendaring. Preferably, during manufacturing, such as during extrusion and/or during calendaring, at least one first core layer is provided with a channel base, wherein at least one side (the upper side and/or the lower side) of the first core layer is patterned to define the location, the length and the width of the channels. In a subsequent step, the patterned side of the first core layer may be covered by at least one second core layer to finally define the channels and to enclose (embed) the channels into the core as such. Bonding of core layers of can for example be realized by means of co-extrusion and/or calendaring, wherein at least one core layer, typically all core layers are preferably sufficiently soft(ened) and/or sticky to allow mutual bonding of the core layers, typically by means of fusion (thus without using a separate adhesive). The second core layer may also be patterned, and may e.g. by provided with a complementary pattern, although it is also imaginable that the second core layer and/or a side of the second core layer facing the first core layer is flat (and thus unpatterned). A, preferably closed, circumferential wall of each channel is defined by a plurality of core layers in this case. In case the core would be composed of a single layer, a, preferably closed, circumferential wall of each channel is defined by the core material of said single layer.

Preferably, at least one, more preferably each, channel has a curved, in particular circular or elliptical cross section, or a polygonal cross-section, such as a triangular, square, pentagonal, hexagonal, rhombic, quadrilateral, and/or octagonal crosssection. At least two channels of a panel may have identical shapes and/or mutually distinctive shapes. At least two channels of a panel may have identical dimensions and/or mutually distinctive dimensions.

It is conceivable that the upper and/or bottom side of the core comprises one extruded groove or a plurality of substantially parallel, extruded grooves, whereby such surface may, for example, provide a form of anti-slip suitable for outdoor decking and/or wherein one or more grooves or other recesses applied in the panel, preferably in the bottom side of the panel, may be configured and/or used for co-action with a separate locking profile and/or a separate locking strip and/or a separate coupling element to fixate the panel onto an underlying support structure, which may, for example, be formed by a frame and/or by one or more beams, such as e.g. extruded beams made of metal, such as aluminium and/or thermoplastic material. Each frame and/or each beam preferably (also) comprises one or more locking grooves to allow the separate locking profile and/or a separate locking strip and/or a separate coupling element to be coupled to said frame and/or beam. This allows that the separate locking profile and/or a separate locking strip and/or a separate coupling element to mechanically connect one or more panels to the underlying support structure, such as a frame and/or one or more beams. The one or more separate locking profiles and/or a separate locking strips and/or a separate coupling elements may make part of the panel covering according to the invention. The same applies to the underlying support structure (if applied), and in case this support structure is mechanically connected to one or more panels according to the invention by means of one or more separate locking profiles and/or a separate locking strips and/or a separate coupling elements.

Outdoor decking can become slippery and hazardous in wet or icy or snowy conditions, therefore the anti-slip surface might be suitable for better safety. As a result, the outdoor decking area comprised of said extruded panels might still be able to be accessible even when it is wet. The substantially elongated grooves are preferably formed by means of extrusion in the same extrusion direction as the core and/or channel(s) extrusion, for the aforementioned reasons why the extrusion method is the preferred method of production. It is imaginable that at least a portion of the surface groove(s) may comprise at least one anti-slip insert, preferably two anti-slip inserts. In a preferred embodiment, it is possible to apply a decor pattern and/or colour pigment(s) onto at least the upper side of the core.

In another preferred embodiment, it is conceivable that at least one decorative top structure, in particular a decorative floor layer, decorative ceiling layer, or decorative wall layer, is affixed, directly or indirectly, on the upper side of the core. Preferably, at least one decorative top structure at least partially covers the upper side of the core and optionally at least partially one or more side edges of the core. Preferably, the decorative top structure comprises at least one, preferably printed, more preferably digitally printed, decorative layer and least one protective layer covering said decorative layer.

The decorative layer may comprise decor print or any decorative structure affixed on the said decorative side of the core either directly or indirectly, and at least one transparent wear layer, acting as protective layer, covering said decorative side. The decorative top structure is preferably formed by printed thermoplastic or paper film, and comprises at least one back layer situated in between the decorative layer and the core layer, wherein said back layer is preferably made of a vinyl compound. A lacquer layer or other protective layer may be applied on top of said wear layer. A finishing layer may be applied in between the decorative layer and the wear layer. The decorative layer will be visible and will be used to provide the panel an attractive appearance. To this end, the decorative layer may have a design pattern, which can, for example be a wood grain design, a mineral grain design that resembles marble, granite or any other natural stone grain, or a colour pattern, colour blend or single colour to name just a few design possibilities. Customized appearances, often realized by digital printing during the panel production process, are also imaginable. The decor print or any decorative structure may also be formed by an ink layer printed, preferably UV-based ink, preferably digitally printed, either directly or indirectly onto the core.

It is preferred that the panel thickness is situated between 3 and 30 mm, preferably from 4-27 mm.

The panel viably comprises coupling profile(s) wherein at least one coupling profile, and preferably all coupling profiles is/are at least partially formed by the core. The panel preferably comprises a pair of a first panel edge comprising a first coupling profile and an opposite second panel edge comprising a second coupling profile being designed to interlock with said first coupling profile of an adjacent panel, typically in a tongue and groove connection. This coupling is preferably such that coupled panels are locked with respect to each other, in a horizontal direction and/or in a vertical direction, preferably in both directions. The first coupling profile at said first panel edge preferably comprises a sideward tongue extending in a direction substantially parallel to the upper side of the panel, wherein the second coupling profile at said second panel edge preferably comprises a groove or recess for accommodating at least a part of said sideward tongue of an adjacent panel. Said is recess preferably defined by an upper lip and a lower lip, said upper lip comprises a recess formed by means of extrusion, and the sideward tongue being designed such that locking takes place by an introduction movement into the recess of the sideward tongue and an angling down movement about an axis parallel to the first edge, as a result of which the bulge on the top side of the sideward tongue will engage the upper lip, leading to a locking of adjacent panels at the first and second edges in both horizontal direction and vertical direction. It is conceivable that each first coupling profile is compatible - hence may co-act and interlock - with each second coupling profile. It is conceivable that each male coupling profile is compatible - hence may co-act and interlock - with each female coupling profile. It is conceivable that at least one coupling profile is compatible - hence may co-act and interlock - with at least two different other coupling profiles of an adjacent panel. This may also apply in case interlocking coupling profiles do not have a completely complementary shape.

In a preferred embodiment, at least one first coupling profile comprises:

• a sideward tongue extending in a direction substantially parallel to a plane defined by the panel, wherein an upper side of said sideward tongue preferably comprises at least one first locking element, such as an upwardly protruding locking element; and wherein at least one second coupling profile comprises:

• a groove configured for accommodating at least a part of the sideward tongue of at least one first coupling profile of an adjacent panel, said groove being defined by an upper lip and a lower lip, wherein said lower lip extends beyond said upper lip, and wherein a lower side of said upper lip preferably comprises at least one second locking element, such as a downwardly facing recess, configured to face, and preferably co-act with, the first locking element of an adjacent panel, in coupled condition of said panels to interlock the panels in horizontal direction.

A locking effect in vertical direction is realized by inserting the sideward tongue of a panel at least partially into the groove of an adjacent panel. Preferably, the first and second coupling profile are configured such that two of such panels can be coupled to each other by means of a turning movement and/or translation movement (preferably in a horizontal plane), wherein, in coupled condition: at least a part of the sideward tongue of a first panel is inserted into the groove of an adjacent, second panel, and wherein at least one second locking element of said first panel faces, and preferably co-acts with, the first locking element of said adjacent panel to interlock both panels both in horizontal and vertical direction.

The lower lip preferably comprises an inner segment, which is positioned directly below the upper lip, and a connecting outer segment, which extends beyond an outer vertical plane defined by the upper lip, wherein the maximum height of the inner segment is identical to or exceeds the maximum height of the outer segment. Hence, the upper surface of a lower lip is preferably substantially planar. It is however imaginable that said upper surface of the lower lip, preferably the outer segment of the lower lip, comprises at least one upward drainage groove. Such a drainage groove (further) facilitates drainage of water, such as water seep in between the coupling profiles.

Preferably, the lower lip of said panel is configured to engage a stop surface of the second profile of an adjacent panel, in coupled condition of said panels, wherein said stop surface is located at a lower level than the sideward tongue. Said stop surface is typically preferably to secure a minimum distance in between top sections of interlocked panels, which typically results in an open seam at the top sections in between interlocked panels which is in favour of the drainage capacity of the covering at least partially formed by said interlocked panels. Preferably, the first coupling profile comprises a first top portion located above the sideward tongue, wherein said first top portion preferably extends in a substantially vertical direction, and wherein an outer end of the upper lip defines a second top portion, wherein said second top portion preferably extends in a substantially vertical direction, and wherein said second top portion is configured to face the first top portion of an adjacent panel, in coupled condition of said panels, preferably such that the first top portion and the facing second top portion are positioned at a distance from each other. As said above, this open (top) seam improves the drainage capacity of the covering at least partially formed by said interlocked panels.

The stop surface is preferably a vertical stop surface. The distant end surface of the lower lip, configured to co-act with said stop surface of another panel, is preferably also oriented substantially vertically, which normally easily leads to a stable abutment of both substantially vertical surfaces. Preferably, a lower side of the panel is provided with a longitudinal cut-out portion connecting and parallel to the first edge for accommodating each lower lip in coupled condition of adjacent panels. Said cut-out portion is preferably partially defined by said stop surface and partially by a connecting horizontal part of the lower side of the panel.

Preferably, the first locking element comprises a bulge and/or a recess, and wherein the second locking element comprises a bulge and/or a recess. The bulge is commonly adapted to be at least partially received in the recess of an adjacent coupled panel for the purpose of realizing a locked coupling, preferably a vertically locked coupling. The curved recess in the upper and/or lower lip, whereby such recess is complimentarily compatible with the bulge on the top or bottom side of the sideward tongue, is preferred to be formed by the extrusion method, substantially parallel with the extrusion direction, as such it is technically difficult to reach by milling technique. The bulge of the adjacently arranged further panel is guided by the curved recess of the panel. Due to its shape, the bulge can withstand a relatively strong force without the risk of getting damaged. Said bulge and recess connection plays an important role as a locking element to interlock the panel with the adjacent panel horizontally, thenceforth the panel and the adjacent panel may interlock in a horizontal direction and in a vertical direction by virtue of all elements of said coupling profiles.

The first locking element is more preferably formed by at least one bulge, and the second locking element is more preferably formed by at least one recess to accommodate said at least one bulge at least partially. This embodiment results in a more robust, and hence stronger, sideward tongue. Preferably, the bulge and/or the recess preferably has a rounded triangular shape, with typically two straight legs being connected by a rounded vertex. The curvature of the vertexes of the bulge and recess may be identical, wherein it is preferred though that a radius defining the vertex of the bulge exceeds the radius defining the vertex of the recess. This makes the bulge less sharp, and therefore less vulnerable for breakage. An inversed embodiment is also imaginable, wherein the first locking element may be formed by at least one recess, and the second locking element may be formed by at least one bulge to accommodate said at least one bulge at least partially. Alternative locking elements and/or other combinations of bulges and recesses are also imaginable as first locking element and second locking element.

Preferably, at least one lower lip is provided with at least one curved side edge, preferably two curved side edges, preferably as seen from a top view of the lower lip. Such curved side edges make the lower lip typically less vulnerable for damaging and/or breaking. The lower lip typically serves for supporting the sideward tongue in coupled condition of adjacent panels. Preferably, in coupled condition of adjacent panels, the sideward tongue is supported both by said inner segment and by said outer segment of the lower lip. Preferably, a distant end portion of the lower side of the sideward tongue, positioned below the first locking element, as said preferably formed by at least one bulge, is at least partially inclined upwardly towards the outer end of the sideward tongue. This inclination creates space which facilitates coupling of the coupling profiles, in particular which facilitates angling in of the sideward tongue into the groove. The outer end of the sideward tongue is preferably substantially vertical, which typically contributes to the robustness of the sideward tongue.

Preferably, at least one sideward tongue is provided with at least one curved and/or chamfered (inclined) side edge, preferably two curved and/or chamfered (inclined) side edges, preferably as seen from a top view of the sideward tongue. These one or more side edges may act as guiding surfaces for aligning the panel(s) with respect to a support structure.

At least two first coupling profiles, in particular as seen from a cross-sectional view, may be identical. Additionally or alternatively, at least two first coupling profiles, in particular as seen from a cross-sectional view, are mutually different. At least two first coupling profiles, in particular as seen from a top view, are mirror symmetric first coupling profiles. In this embodiment, the mirror symmetric first coupling profiles are preferably separated by an intermediate segment, in particular a drainage segment, which makes the two adjacent first coupling profiles look like an interrupted larger first coupling profile being divided into two smaller first coupling profiles. Said (fictive) larger first coupling profile may have the same length (as seen in the direction of the first edge) which as another (undivided) first coupling profiled located at said first edge. The same applies to the second coupling profiles which may be identical and/or deviating coupling profiles. At least two second coupling profiles, in particular as seen from a top view, may be mirror symmetric second coupling profiles.

Preferably, the coupling profiles make integral part of the panel, in particular a core of the panel. More preferably, the coupling profiles are at least partially formed by means of extrusion, preferably simultaneously with at least one layer, such as a core layer, of the panel. Said layer and the coupling profiles may therefore be made out of one piece of material. It is well imaginable that the coupling profiles are milled and/or otherwise brought into their final shape (also in length direction parallel to the first and second side edges) after extrusion.

Alternatively and/or additionally the panels may be arranged to be coupled with an angling (down) motion. Such motion may also be referred to as rotational motion, wherein a portion of a new panel is inserted into a portion of a panel already placed and fully inserted through an angling motion. In a preferred embodiment, the panel comprises at least one third coupling profile and at least one fourth coupling profile arranged on another pair of opposite sides of the panel, wherein the third coupling profile of said panel and the fourth coupling profile of another panel are preferably arranged to be coupled by means of an angling down motion. Preferably, the third coupling profile comprises: a sideward tongue extending in a direction substantially parallel to the upper side of the core, at least one second downward flank lying at a distance from the sideward tongue, and a second downward groove formed between the sideward tongue and the second downward flank, and wherein the fourth coupling profile comprises: a third groove configured for accommodating at least a part of the sideward tongue of the third coupling profile of an adjacent panel, said third groove being defined by an upper lip and a lower lip, wherein said lower lip is provided with an upward locking element, wherein the third coupling profile and the fourth coupling profile are configured such that two of such panels can be coupled to each other by means of a turning movement, wherein, in coupled condition: at least a part of the sideward tongue of a first panel is inserted into the third groove of an adjacent, second panel, and wherein at least a part of the upward locking element of said second panel is inserted into the second downward groove of said first panel.

In an embodiment, the panels comprises, at least at a first pair of opposite edges, a first coupling profile and a second coupling profile allowing that several of such panels can be coupled to each other, whereby these coupling profiles, in coupled condition of two of such panels, provide a locking in a first direction (R1 ) perpendicular to the plane of the panels, as well as in a second direction (R2) perpendicular to the respective edges and parallel to the plane of the panels, wherein said first coupling profile comprises a sideward tongue, wherein said sideward tongue comprises a front region and a back region, wherein a top surface of the front region is preferably at least partially inclined downwardly in a direction away from the back region, and wherein a bottom surface and/or side surface of the back region of said sideward tongue defines a first contact portion, and wherein the sideward tongue comprises a passive bottom surface situated adjacent to the first contact portion, wherein said second coupling profile comprises a recess (or groove) for accommodating at least a part of the sideward tongue of a further panel, said recess being defined by an upper lip and a lower lip, wherein the lower lip extends beyond the upper lip, and wherein the lower lip being provided with a upwardly protruding shoulder defining a second contact portion configured to co-act, in particular actively co-act, with said first contact portion of another panel, in coupled condition of said panels, such that that the panels are forced with a force, in particular a tension force (T1), at least laterally towards each other, wherein a top surface of said lower lip is curved, in particular smoothly curved, at least partially, and wherein said at least partially curved top surface of the lower lip and said passive bottom surface of the sideward tongue are mutually situated such that, in coupled condition of two panels, an intermediate space is present adjacent to actively co-acting first and second contact portions, and wherein a lower surface of the upper lip is preferably at least partially inclined and configured to abut at least a part of the top surface of the front region of the sideward tongue of another panel. These coupling profile may replace other coupling profiles or be used in combination therewith.

At least one pair of opposing edges, typically formed by a third edge and fourth edge, of the panel may be entirely free of coupling profiles. In this case these opposing edges are defined by substantially vertical end surfaces.

In an embodiment of the panel according to the invention at least one pair of coupling profiles comprises a third coupling profile and a fourth coupling profile, the third coupling profile comprises an upward tongue, at least one upward flank lying at a distance from the upward tongue and an upward groove formed in between the upward tongue and the upward flank, wherein the upward groove is adapted to receive at least a part of a downward tongue of the second coupling profile of another panel, wherein the side of the upward tongue facing towards the upward flank is the inside of the upward tongue and the side of the upward tongue facing away from the upward flank is the outside of the upward tongue; wherein the second coupling profile comprises a downward tongue, at least one downward flank lying at a distance from the downward tongue, and a downward groove formed in between the downward tongue and the downward flank, wherein the downward groove is adapted to receive at least a part of the upward tongue of the third coupling profile of another panel, wherein the side of the downward tongue facing towards the downward flank is the inside of the downward tongue and the side of the downward tongue facing away from the downward flank is the outside of the downward tongue. Preferably, the outside of the downward tongue and the upward flank both comprise an upper contact surface near, or at, or adjoining, or towards a top side of the panel, wherein preferably at least one of said contact surfaces extends vertically at least partly, and preferably completely, and wherein the upper contact surface of the outside of the downward tongue of said panel is configured to engage the upper contact surface of the upward flank of an adjacent panel, in coupled condition of said panels. Preferably, below, more preferably adjoining, the upper contact surfaces both the downward tongue and the upward flank comprise an inclined contact surface, wherein the inclined contact surface of the downward tongue of said panel is configured to engage the inclined contact surface of the upward flank of an adjacent panel, in coupled condition of said panels, wherein each vertical part of the upper contact surface and each adjoining inclining surface mutually enclose an angle (a) between 100 and 175 degrees. Preferably, adjoining the inclined contact surface the downward tongue comprises an outer surface, situated below the inclined contact surface of the downward tongue, and adjoining the inclined contact surface the upward flank preferably comprises an inner surface, situated below the inclined contact surface of the upward flank, wherein the outer and inner surface run substantially parallel and extend at least partly in vertical direction; wherein, in coupled condition of adjacent panel, a space is present between at least a part of the outer surface of said panel and at least a part the inner surface of an adjacent panel. Such panels are typically arranged to be coupled with a downward motion. Such motion is also referred to as drop-down or vertical motion, and may mean that a new panel can be pushed into a panel already placed. Such coupling is also possible when panels are connected through a zipping or scissoring motion.

Additionally or alternatively the panel may comprise at least one third, preferably resilient, coupling profile and at least one fourth, preferably resilient, coupling profile connected respectively to opposite edges of the core, which third coupling profile comprises a single tongue, at least one upward flank lying at a distance from the upward tongue and a single upward groove formed between the upward tongue and the upward flank, wherein: at least a part of a side of the upward tongue facing toward the upward flank extends in the direction of the normal of the upper side of the core, at least a part of a side of the upward tongue facing toward the upward flank forms an aligning edge for the purpose of coupling the third coupling profile to a fourth coupling profile of an adjacent floor panel, at least a part of a side of the upward tongue facing away from the upward flank is optionally provided with a first locking element which is connected substantially rigidly to the upward tongue and adapted for co-action with an optionally applied second locking element of a fourth coupling profile of an adjacent floor panel, which fourth coupling profile comprises a single downward tongue, at least one downward flank lying at a distance from the downward tongue, and a single downward groove formed between the downward tongue and the downward flank, wherein: at least a part of a side of the downward tongue facing toward the downward flank extends in the direction of the normal of the lower side of the core, at least a part of a side of the downward tongue facing away from the downward flank forms an aligning edge for the purpose of coupling the fourth coupling profile to a third coupling profile of an adjacent floor panel, the downward flank is provided with an optionally second locking element which is connected substantially rigidly to the downward flank and adapted for co-action with an optionally applied first locking element of a third coupling profile of an adjacent floor panel, wherein the upward groove is adapted to receive at least a part of a downward tongue of an adjacent panel, and wherein the downward groove is adapted to receive at least a part of an upward tongue of an adjacent panel. Because the coupling profiles are given a specific form and moreover take a (somewhat) resilient form, the substantially complementarily formed coupling profiles of adjacent floor panels can be coupled to each other relatively simply, but durably and efficiently. During coupling of adjacent floor panels a force will here be exerted on one or both coupling profiles, whereby the one or both coupling profiles will deform elastically (move resiliently), as a consequence of which the volume taken up by the downward groove and/or upward groove will be increased such that the upward tongue and the downward tongue can be arranged relatively simply in respectively the downward groove and the upward groove. By subsequently allowing the forced coupling profiles to move back resiliently to the original position a reliable, locked coupling will be realized between the two coupling profiles, and thereby between the two floor panels. This locked coupling, wherein both coupling profiles mutually engage in relatively reliable manner, will counter friction of parts of the coupling against each other, whereby the coupling as such will generally generate relatively little noise. The applied aligning edges, generally also referred to as chamferings or guide surfaces, herein facilitate hooking together of the two coupling profiles by the substantially linear displacement of the coupling profiles relative to each other. Applying the mutually co-acting locking elements prevents a substantially vertical displacement of the two floor panels relative to each other. Because both the first locking element and the second locking element are connected substantially rigidly to respectively the upward tongue and the downward flank, a relatively durable and strong locking can be realized, since no use is made of relatively weak resilient locking parts in which material fatigue could moreover occur relatively quickly. The locking in the floor panel according to the invention is realized by deforming the third coupling profile and/or the fourth coupling profile relative to the core, whereby the locking elements can engage round each other or into each other. As a result of the rigid connection to the upward tongue and the downward flank, deformation of the locking elements themselves does not occur, or hardly so. The first locking element can otherwise form an integral part of the upward tongue, wherein the first locking element can for instance be formed by a protruding (outward bulging) or recessed (inward bulging) edge deformation of the upward tongue. The second locking element can also form an integral part of the downward tongue, wherein the second locking element can for instance be formed by a recessed or protruding edge deformation of the downward flank. The upward groove of the third coupling profile will generally be given a form such that it is adapted for receiving in locked manner at least a part of a downward tongue of a fourth coupling profile of an adjacent floor panel. A first locking will thus be formed by confining the downward tongue of a floor panel in the upward groove of an adjacent floor panel and by confining the upward tongue of the adjacent floor panel in the upward groove of the floor panel, and a second locking will be formed by applying the locking elements. The normal is understood to mean a normal vector of a plane, i.e. a vector perpendicular to this plane and thus originating from said plane. If the upper side or the lower side of the core were to be not completely flat, for instance because the upper side or the lower side of the core takes a form which is (to some extent) profiled, a plane formed by the upper side or lower side of the core can then be taken as basis to enable definition of an unambiguous direction of the normal of the upper side or the lower side of the core. Since the floor panel will generally support on a flat, horizontal surface, the direction of the normal of both the upper side of the core and the lower side of the core will then be oriented substantially vertically. The characteristic orientation of the side of the upward tongue facing toward the upward flank, the side of the downward tongue facing toward the downward flank, provides for a first locking mechanism (inner lock) during coupling of the floor panel to an adjacent floor panel. This is because, owing to the characteristic inclining orientation of the tongue walls facing toward the respective flanks, the exerting of (for instance) a vertical force on the coupling is not likely to result in an uncoupling of the co-acting coupling profiles, since the relevant tongue walls are pressed against each other, which is a considerable constraint to the tongue walls sliding off each other and subsequent uncoupling of the coupling profiles. In addition, at a distance from the first locking mechanism a second locking mechanism (outer lock) is formed by the locking elements which co-act mutually, and furthermore at a distance from the above mentioned (inner) tongue walls, in a coupled position of two floor panels. In the case of possible failure of one of the locking mechanisms, securing of the coupling between the two floor panels will be maintained as far as possible, this resulting in a relatively reliable coupling between the two floor panels, whereby undesirable mutual displacement or uncoupling of the floor panels can be prevented as far as possible. Because the floor panel according to the invention will realize a multiple locking when the floor panel is coupled to an adjacent floor panel, a relatively firm, reliable and durable connection can be realized between the floor panels.

The invention additionally relates to a method of producing a decorative panel, in particular a decorative panel according to the invention, comprising the steps of: a. liquifying a polymer-based core composition; b. extruding said liquified polymer-based core composition to form a soft core sheet; simultaneously extruding said soft core sheet through the extrusion process in which channels and/or grooves are formed, i. wherein during the extrusion process at least one channel and/or groove is formed by means of forcing at least one extrusion die into said soft core sheet, ii. wherein the at least one channel or groove is arranged at a distance from the lower side and/or the upper side, wherein the at least one groove is arranged as a mean of coupling profile, c. allowing the core sheet provided with the core channels and/or grooves to solidify.

Alternatively the method comprises the steps of: a. liquifying a polymer-based core composition; b. extruding said liquified polymer-based core composition to form a soft core sheet; i. forming at least one channel is formed in the core sheet, at a distance from the lower side and/or the upper side of the core sheet, ii. forming tongue and groove coupling profiles at the edges of the core sheet; c. allowing the core sheet provided with the core channels and/or grooves to solidify.

In one preferred embodiment, a preferred action may be performed, wherein during step c) the extruded core is actively cooled down, preferably by means of cooling liquid or gas or surface. In another preferred embodiment, another preferred action may be performed, wherein after step c) a decorative top structure is applied onto the upper side of the core sheet either directly or indirectly, as such a decorative plate is formed and at least one transparent wear layer covering said decorative side or a decor pattern is applied onto the upper side of the core sheet. Preferably, further action may comprise step d) cutting the solid core sheet or decorated sheet into a plurality of panels.

Embodiments of the invention are presented in the non-limitative set of clauses presented below.

1 . A panel, in particular a floor panel, a ceiling panel, or a wall panel, comprising: o an extruded core provided with an upper side and a lower side on opposite sides of the core, wherein the core comprises at least an extruded polymer material, o coupling profiles arranged on at least two opposite edges of said core, wherein the coupling profiles are integrated with the core material, wherein said coupling profiles are designed to interlock with coupling profiles of an adjacent panel with coupling profiles to provide locking both in a horizontal direction and/or in a vertical direction, and o wherein the core comprises at least one channel, , wherein the at least one channel is arranged at a distance from the lower side and/or the upper side of said core.

2. Panel according to clause 1 , wherein the core comprises a plurality of core layers, preferably co-extruded core layers, wherein at least two core layers mutually enclose at least one channel, preferably each channel, and/or wherein at least two core layers together define a circumferential wall of at least one channel, preferably each channel.

3. Panel according to one of the preceding clauses, wherein the volume enclosed by at least one channel, and preferably by all channels together, is at least 20%, preferably between 30% and 50% of the total volume enclosed by the core. 4. Panel according to any of the preceding clauses, comprising multiple channels, wherein one channel is located next to each other or on top of another channel, wherein at least one channel comprises the same or a different shape compared to at least one other channel.

5. Panel according to any of the preceding clauses, wherein the at least one channel is arranged at a distance from the sides of the core or from the coupling profiles.

6. Panel according to any of the preceding clauses, wherein the at least one channel is surrounded at the top and bottom by at least one of the core material(s), preferably also surrounded at the sides by at least one of the core material(s).

7. Panel according to one of the preceding clauses, wherein the extrudable polymer material at least comprises of a thermoplastic and/or a thermoset material, for example, ethylene-vinyl acetate (EVA), which is a copolymer of ethylene and vinyl acetate, rubber, polyurethane (PU), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinylchloride (PVC), or mixtures thereof.

8. Panel according to one of the preceding clauses, wherein the core is at least partially made of foamed thermoplastic and/or a thermoset material, preferably recycled plastic material, wherein the core comprises at least 50% of its weight of the thermoplastic material, preferably 50% up to 100% of its weight of the thermoplastic material.

9. Panel according to one of the preceding clauses, wherein the core comprises at least one plasticizer.

10. Panel according to one of the preceding clauses, wherein the core comprises at least one polymer material and preferably at least one non-polymeric material, for example, talc, chalk, glass particles, calcium carbonate (CaCO3), and/or cellulose-based particles. 11 . Panel according to one of the preceding clauses, wherein the areal density of the core is less than 9000 g/m2, preferably less than 6000 g/m2, more preferably around 5000 g/m2.

12. Panel according to one of the preceding clauses, wherein the panel comprises at least one decorative top structure affixed, directly or indirectly, to the core and at least partially covering the upper side of the core and optionally at least partially at least one side edge of the core.

13. Panel according to clause 12, wherein the decorative top structure comprises at least one, preferably printed, more preferably digitally printed, decorative layer and least one protective layer covering said decorative layer.

14. Panel according clause 13, wherein the decorative layer comprises a decor formed by an ink layer printed, preferably a UV-based ink, preferably digitally printed, either directly or indirectly onto the core.

15. Panel according to any of the preceding clauses, wherein the upper side of the core and/or of the panel comprises a plurality of parallel, extruded grooves.

16. Panel according to one of the preceding clauses, wherein the panel thickness is situated between 3 and 30 mm, preferably between 4-27 mm.

17. Panel according to any of the preceding clauses, wherein the panel comprises a pair of a first panel edge comprising a first coupling profile and an opposite second panel edge comprising a second coupling profile being designed to interlock with said first coupling profile of an adjacent panel in a tongue and groove connection, preferably both interlock in a horizontal direction and in a vertical direction, wherein the pair of opposite edges comprises: o a first edge comprising a sideward tongue extending in a direction substantially parallel to the upper side of the panel, a bulge on top of the edge of the sideward tongue, o an opposite, second edge comprising a recess for accommodating at least a part of the sideward tongue of a further panel, said recess being defined by an upper lip and a lower lip, said upper lip comprises a recess formed by means of extrusion, o the sideward tongue being designed such that locking takes place by an introduction movement into the recess of the sideward tongue and an angling down movement about an axis parallel to the first edge, as a result of which the bulge on the top side of the sideward tongue will engage the upper lip, leading to a locking of adjacent panels at the first and second edges in both horizontal direction and vertical direction.

18. Panel according to one of the preceding clauses, wherein the pair of opposite edges comprises: o a first edge comprising a sideward tongue extending in a direction substantially parallel to the upper side of the panel, a bulge on a bottom of the edge of the sideward tongue, wherein the first downward groove is adapted to receive at least a part of a second upward tongue of a second coupling profile of an adjacent panel, o an opposite, second edge comprising a recess for accommodating at least a part of the sideward tongue of a further panel, said recess being defined by an upper lip and a lower lip, said lower lip comprises a recess formed by means of extrusion, o the sideward tongue being designed such that locking takes place by an introduction movement into the recess of the sideward tongue and an angling up movement, as a result of which the bulge on the bottom side of the sideward tongue will engage the lower lip, leading to a locking of adjacent panels at the first and second edges in both horizontal direction and vertical direction.

19. Panel according to one of the preceding clauses, wherein at least one coupling profile, and preferably all coupling profiles, is at least partially formed by the core.

20. Panel according to one of the preceding clauses, wherein the core is formed along an extrusion direction, and wherein the channels and/or grooves is formed in said extrusion direction. 21 . Panel according to one of the preceding clauses, wherein the core comprises a centre portion and a peripheral portion enclosing said centre portion, wherein the panel edges and coupling profiles make part of said peripheral portion, and wherein said peripheral portion is free of core channels and/or grooves.

22. Method of producing a panel, in particular a floor panel, a ceiling panel, or a wall panel, comprising the steps of: a. liquifying a polymer-based core composition; b. extruding said liquified polymer-based core composition to form a soft core sheet; a. forming at least one channel is formed in the core sheet, at a distance from the lower side and/or the upper side of the core sheet, b. forming tongue and groove coupling profiles at the edges of the core sheet; c. allowing the core sheet provided with the core channels and/or grooves to solidify.

23. Method according to clause 22, wherein during step c) the extruded core is actively cooled down, preferably by means of cooling liquid or gas or surface.

24. Method according to clauses 22 and/or 23, wherein after step c) a decorative top structure is applied onto the upper side of the core sheet either directly or indirectly, as such a decorative plate is formed and at least one transparent wear layer covering said decorative side or a decor pattern is applied onto the upper side of the core sheet.

25. Method according to clauses 22-24, further comprising the step of: d. cutting the solid core sheet or decorated sheet into a plurality of panels.

Further advantages, features, and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

- Figures 1 A and 1 B illustrate a cross-sectional view of a panel in accordance with the present invention, with an extruded groove on the upper side and with a decorative layer on the upper side, respectively, both with coupling profiles and one channel arranged in the core; - Figure 2A and 2B illustrate a cross-sectional view of a panel in accordance with the present invention, with an extruded groove on the upper side and with a decorative layer on the upper side, respectively, both with coupling profiles and multiple channels arranged in the core;

- Figure 3A, 3B, 4A, and 4B illustrate a cross-sectional view of a panel in accordance with the present invention, with an extruded groove on the upper side and with a decorative layer on the upper side, respectively, both with coupling profiles and multiple channels arranged in the core, arranged next to an identical floor panel in a coupled state;

- Figures 5A and 5B illustrate a cross-sectional view of a panel in accordance with the present invention, with an extruded groove on the upper side and with a decorative layer on the upper side, respectively, both with coupling profiles and multiple channels arranged in the core, wherein the core is coextruded with two different compositions;

- Figures 6A and 6B illustrate a cross-sectional view of a panel in accordance with the present invention, with an extruded groove on the upper side and with a decorative layer on the upper side, respectively, both with coupling profiles and multiple channels filled with fillers arranged in the core, wherein the core is co-extruded with two different compositions.

Figures 1 A and 1 B show a cross section of a single panel 100 according to the present invention. This figure allows for a more detailed elaboration on the first coupling profile 101 and the second coupling profile 102. the first coupling profile 101 and the second coupling profile 102 are preferably realised by means of extrusion. At least one of the first coupling profiles 101 comprises a sideward tongue 105. An upper side, or upwardly facing surface of said sideward tongue 105 comprises at least one first locking element 106. In this particular embodiment, said first locking element 106 is formed by an upwardly facing bulge 106. Preferably, said first locking element 106 stretches beyond the average surface height of the sideward tongue 105. As such, said first locking element may function as a horizontal locking element. A lower side of the panel 100 is provided with a cut-out portion 103, which cut-out portion according to this embodiment is connecting to and parallel to the first edge. Said cut-out portion is provided for allowing said first edge to accommodate a portion of the second coupling profile 102, in particular a lower lip 104 thereof. A downwardly facing surface of the sideward tongue 208 may be provided with a chamfer cut, which may allow the panel to be angled downwardly into the second coupling profile 102 of an adjacent panel 100. The second coupling profile 102 comprises a groove 110 for accommodating at least a portion of the sideward tongue 105 of a first coupling profile 101. The groove 110 is at least partially defined by a lower lip 104 and an upper lip 108. Said lower lip 104 may be accommodated by a cut-out portion 103 in a coupled condition of adjacent panels 100. In this particular embodiment, a downward facing surface of the upper lip 108 is provided with a second locking element 109. In this embodiment, said second locking element 109 may be formed by a recess 109. A recess 109 may be formed by means of extrusion. Said second locking element configured to receive at least a portion of the first locking element 210, wherein said first locking element 106 and second locking element 109 mutually lock adjacent panels 100. At least one lower lip 104 may be provided with a recessed portion 111 , which may function as a drainage channel when panel 100 is applied as outdoor panel. An upper surface of the panel 100 may comprise a plurality of grooves 112 and protruding area 113. Grooves 112 may be realised by means of extrusion. Grooves 112 may stretch over substantially the entire length of the panel 100 as such, or may stretch over a part thereof. Although it is conceivable that said grooves 112 are substantially horizontal, it is also conceivable that a first end of the grooves 112 is lower compared to an opposed second end of the grooves 112. Furthermore, for outdoor use, at least one through hole may be provided in at least one of the excavations, for allowing water to drain through said hole. In this respect, the hole may extend through the entire panel 100. It is also conceivable, as seen in figure 1 B, that the panel 100 may comprise decorative part 118, preferably for indoor use. A central portion of the core panel 100 may comprise channel 116. This may reduce the weight of the panel, which may save costs in terms of material and shipping. Panel 100 may comprise different thickness, depending on the use for outdoor or indoor. Preferably outdoor panel 100 is thicker than indoor panel 100. The panel 100 may comprise a core portion 117. In this respect, at least one first coupling profile 101 and at least one second coupling profile 102 make an integral part of said core 117. The core 117 may at least partially be composed of thermoplastic material, said thermoplastic material is chosen from the group consisting of: PVC, PET, PP, PS, thermoplastic polyurethane (TPU), PE, in particular MDPE and/or HDPE; and combinations thereof. It is imaginable that each of the first coupling profile 101 and second coupling profile 102 comprise a first top portion 114 and second top portion 115 respectively. Said first top portion 114 and second top portion 115 preferably extending in a vertical direction. The first top portion 114 is located above the sideward tongue 105 of the first coupling profile 101. The second top portion 115 may be at least partially, preferably entirely, formed by an outer end of the upper lip 108.

Figures 2A and 2B show a cross section of a single panel 200 according to the present invention. In this preferred, non-limiting embodiment, it is shown that the panel 200 may comprise two compositions of the core, upper layer 201 of the core, and lower layer of the core 202. It is imaginable that the core is provided with at least two zones of different compositions (201 and 202), as such zones may at least partially be composed of thermoplastic material, said thermoplastic material is chosen from the group consisting of: PVC, PET, PP, PS, thermoplastic polyurethane (TPU), PE, in particular MDPE and/or HDPE; and combinations thereof. Such zones may be obtained, for example, by means of co-extrusion. It is also imaginable that panel 200 may comprise multiple channels 203, which may also offer the same functions as single channel 116 without reducing the strength and rigidity of panel 200. A turning movement may be performed to insert the sideward tongue 105 into the groove 110.

Figures 3A and 3B show a cross section of a single panel 300 according to the present invention. In this preferred, non-limiting embodiment, it shows a coupled condition 301 of two adjacent panels 300. For example, the bulge 303 may be received by the recess 305 of an adjacent panel 300 as the sideward tongue 302 is at least partially inserted by angling or turning movement into the groove 304. These locking elements may perform the interlocking connection in both vertical and horizontal directions, respectively, of the two adjacent panels 300. It is shown that channel 306 may comprise of circular shape, as an example of the non-limited shapes, and/or height, and/or width the at least one channel may comprise in the present invention. Panel 300b shows that the panel may comprise two zones of core layers, which preferably be realised by means of extrusion.

Figure 4A and 4B show other preferred, non-limiting embodiments according to the present invention, wherein the channels 401 may comprise different shapes, and/or height, and/or width in one panel 400. More in particular, each of Figure 4A and 4B show centre channels which are centrally located in the core of these panels. The heart of each centre channel may intersect with a central plane of the core. It is also imaginable that the heart of each centre channel is positioned at a distance from the central plane of the core, but wherein the centre channels as such intersect with said central plane. A circumferential wall of each centre channel is entirely composed of core material. Additionally, each of Figure 4A and 4B show bottom channels which are located at the bottom side of the core, and which are optionally, as shown, covered by a separate backing layer, such as a cork layer and/or an EVA layer. The backing layer is typically glued onto the bottom side of the core. With respect to these bottom channels a circumferential wall of each bottom channel is partially formed by core material and partially formed by backing layer material. It is imaginable that the panel according to the invention is free of centre channels and only comprises eccentric channels, such as the bottom channels. It is also imaginable that the panel according to the invention is free of bottom channels and only comprises centre channels. Figure 5A an 5B show other preferred, non-limiting embodiments according to the present invention, wherein a panel 500 comprises a third coupling profile 501 on one edge and a fourth coupling profile 502 on the opposite edge of the edge comprising the third coupling profile 501 . The coupling profiles 501 , 502 are configured to allow adjacent panels 500 to be interlocked by means of a drop-down or lowering movement, preferably both in horizontal and vertical direction. It is also seen in the figures that channels 503 are located a part in the upper core layer 504 and another part in the lower core layer 505, as such combination may have different compositions and may be realised by means of co-extrusion. Each channel 503 is shown in Figure 5A as an oval shape, which is also not limiting in terms of shapes, and/or height, and/or width. The oval shape is partially determined by the upper core layer 504 and partially determined by the lower core layer 505. Alignment of these two layers during lamination, in particular during calendaring, is often important to end up with the oval shapes as depicted in Figure 5a. In Figure 5b, each channel 503 is dome shaped, wherein the shape of each dome is solely determined by the upper core layer 504 and wherein the lower core layer 505 merely functions as (planar) cover layer to close off a circumferential wall of the channels 503. Each of the channels 503 preferably has open end sections. Figure 6A and 6B show other preferred, non-limiting embodiments of panels 600a, 600b according to the present invention. Each panel 600a, 600b comprises a third coupling profile 601 on one edge and a fourth coupling profile 602 on the opposite edge of the edge comprising the third coupling profile 601 . The coupling profiles 601 , 602 are configured to allow adjacent panels 500 to be interlocked by means of a drop-down or lowering movement, preferably both in horizontal and vertical direction. Each panel 600a, 600b comprises channels 603, being filled with fillers, wherein such fillers comprise at least a (sound- and/or impact dampening) material. A combination of upper core layer 604, lower core layer 605, and multiple channels filled with fillers 603 may be aimed to provide better sound insulation while maintaining the quality, rigidity, and strength of panel 600. Each channel 603 has a rectangular cross-section. As shown in Figures 6A and 6B, the shape of the channels 603 may mutually vary. As shown in Figure 6A, the shape of the rectangular channels 603 is defined by the upper core layer 604 only, wherein the lower core layer 605 merely functions as (planar) cover layer to close off a circumferential wall of the channels 603. In Figure 6B, the shape of the rectangular channels is partially determined by the upper core layer 604 and partially determined by the lower core layer 605. Alignment of these two layers during lamination, in particular during calendaring, is often important to end up with the rectangular shapes as depicted in Figure 6a. Each of the channels 603 preferably has open end sections.

The coupling profiles may also be referred to as coupling profiles or as connecting profiles. "Complementary" coupling profiles mean that these coupling profiles can cooperate with each other. However, to this end, the complementary coupling profiles do not necessarily have to have complementary forms. By locking in "vertical direction" is meant locking in a direction perpendicular to the plane of the panel. By locking in "horizontal direction" is meant locking in a direction perpendicular to the respective coupled edges of two tiles and parallel to or falling together with the plane defined by the panel. 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”. The present invention has been described using detailed embodiments thereof. It will be apparent that the invention is not limited to the working examples shown and described herein, but that numerous variants are possible within the scope of the attached claims that will be obvious to a person skilled in the art.

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