Panel and method for producing panel

Abstract

The present invention relates to a panel comprising a composite layer comprising a thermoplastic foamed substrate and a reinforcing frame, and comprising a decorative layer adhered to at least one surface of the composite layer. The panels are typically made by extrusion.

Description

Technical Field

[0001] The present invention relates to a panel. The present invention also relates to a method of manufacturing a panel. Background Art

[0002] Building and / or decorative panels generally used in furniture, shelves, floors, door panels, and building boards are usually mainly made of wood, and the core layer of the panel is composed of particle board, high-density fiberboard (HDF), medium-density fiberboard (MDF), oriented strand board (OSB), plywood, etc. However, these wood panels have several disadvantages. They are vulnerable to humidity fluctuations and water, which may cause warping and delamination; they are usually anisotropic, and the material has different physical properties, such as stiffness, expansion, and / or swelling, depending on the measured axis, which may be disadvantageous when fastening devices are provided; and they may have local defects, such as cracks or knots, which may affect the local strength.

[0003] A well-known alternative to the above panels is a composite board comprising a thermoplastic polymer matrix mixed with natural fibers. These types of panels are more dimensionally stable, but are prone to delamination due to low surface energy. In addition, due to the nature of the thermoplastic plastics, including low surface energy, thermal sensitivity, and lack of polar groups that can promote adhesion, the thermal lamination of the panel composite layers, such as at least one decorative top layer thermally laminated to at least one core layer, may be challenging. Another disadvantage of existing composite boards includes low screw fixing strength and low load bearing capacity, which usually results in adding excessive number of layers, increasing additional weight and cost, which are undesirable for both manufacturers and consumers.

[0004] Known surface treatment methods for enhancing adhesion can be divided into chemical treatment, mechanical treatment, and heat treatment. Chemical treatment or thermal surface treatment usually includes radiation, such as UV, excimer, or chemical modification, chromic acid treatment, corona treatment, plasma treatment, polymer modification, or a combination thereof. However, due to long-term exposure on the surface, some of these methods may affect the core of the thermoplastic polymer matrix inside the panel. Therefore, some materials may react or their structure may be damaged when exposed to certain types of surface modification. Evaluating the compatibility of the floor material with the selected surface modification method is crucial, which may be costly and time-consuming. Certain forms of radiation are also dangerous to machine operators. On the other hand, mechanical treatment, such as abrasion, scrubbing, or grinding, may cause surface damage, especially if the material is fragile, and the result may lead to poor appearance or feel.

[0005] In the prior art, it is known to use reinforcing layers and / or fillers to increase the strength of thermoplastic composite panels. This is usually done to increase tensile or impact strength, dimensional stability, and / or flexibility. According to the prior art, one disadvantage of such reinforcing layers is that, in addition to increasing strength and strengthening the overall structure, they are rarely used for other purposes in the paneling.

[0006] Therefore, there is a need for an improved panel structure that addresses the existing problems by maintaining and / or reducing the weight of the panel, increasing dimensional stability and load-bearing capacity, while enhancing its surface properties in a cost-effective manner. The synergistic effect of these properties will be achieved by adding at least one reinforcing frame. The object of the present invention is to provide an improved lightweight and dimensionally stable panel for use as a decorative element in furniture, shelving, flooring, door panels, and building materials, or at least to provide an alternative to known panels. Summary of the Invention

[0007] The present invention provides a panel comprising at least one core layer, in particular at least one composite core layer, the core layer comprising at least one thermoplastic foam substrate and at least one reinforcing frame, and at least one decorative layer adhered to at least one surface of the core layer, wherein at least one core layer comprises a front surface and a rear surface located on opposite sides, and wherein at least one reinforcing frame is embedded within at least one core layer such that, when viewed from the front surface and / or the rear surface of at least one core layer, at least a portion of the outer periphery of at least one reinforcing frame is located at 20% or less of the thickness of the core layer.

[0008] Preferably, at least a portion of the outer periphery of at least one reinforcing frame is adjacent to the core layer surface but does not extend beyond the thickness of the core layer.

[0009] The panel according to the present invention addresses at least some of the above-mentioned drawbacks and provides an alternative to the prior art by embedding at least one reinforcing frame in the core layer of the panel while exhibiting an increase in surface energy and an enhancement in load-bearing capacity. The panel according to the present invention benefits from at least one reinforcing frame. The reinforcing frame can be, but is not limited to, a mesh, network, grid, reticulation, line, strip, cloth, and / or a combination thereof. At least one reinforcing frame can be composed of a material that is at least partially embedded in the surface of at least one core layer. Such a reinforcing frame has better anchoring properties than thermoplastic composites and can be achieved without any surface treatment. It provides structural support, enhances the anchoring properties, and improves the overall mechanical properties of the thermoplastic foamed substrate. A non-limiting example of a material in which at least a part of at least one reinforcing frame can be composed of a fiber material, such as glass fiber, polymer fiber, or a fiber material derived from a polymer precursor, such as glass fiber, polymer fiber, or a fiber material derived from a polymer precursor, such as aramid fiber, carbon fiber, polyamide fiber, polyaramide fiber, polypropylene fiber, polyester fiber, such as polyethylene terephthalate (PET), polyvinyl alcohol (PVOH), polyvinyl acetate (PVAc), polypropylene (PP), polyamide, PET, diol-modified PET (PET-g), polyethylene, acrylic fiber, polyvinyl chloride (PVC), rPVC; mineral fibers, such as calcium carbonate, basalt fiber, talc, mica, wollastonite, tricalcium phosphate (TCP); organic / natural fibers, such as jute fiber, hemp, bamboo, flax, mycelium, wood flour, and / or fibers including microfibers, cotton, or a combination thereof. The fibers in the fiber material can be coated or uncoated. Non-limiting examples of non-fiber materials include metals, such as aluminum, steel (including stainless steel and galvanized steel), brass, bronze, etc. It is conceivable that at least one reinforcing frame is formed by non-connected particles, micron, and / or nanoparticle (such as nanoclay, including montmorillonite, carbon nanotubes, and graphene, polymer microspheres) dispersed in the thermoplastic substrate. This can also enhance the material of the thermoplastic foamed substrate and improve the mechanical properties, thermal stability, and / or barrier properties of the panel.

[0010] At least one reinforcing frame is encapsulated within at least one core layer, particularly within at least one thermoplastic foamed substrate. The at least one reinforcing frame can be encapsulated within at least one core layer, particularly encapsulated within at least one thermoplastic foam substrate, made of the same material as the at least one thermoplastic foamed substrate. For example, an inner shell layer can be formed around at least a portion of the at least one reinforcing frame such that at least a portion of the at least one reinforcing frame is encapsulated within the at least one core layer, particularly within at least one thermoplastic foamed substrate. In this embodiment, the synergistic effect between the reinforcing frame and the thermoplastic foamed substrate can be further optimized. It is also possible that at least one core layer includes at least one upper shell layer located on the front surface and / or at least one lower shell layer located on the rear surface. The at least one reinforcing frame can be at a certain distance from the at least one upper shell layer and / or the at least one lower shell layer. It is also conceivable that at least one inner shell layer overlaps or integrates into the at least one upper shell layer and / or the at least one lower shell layer.

[0011] In a possible embodiment, during the foaming step of the uncured core layer, particularly the thermoplastic foamed substrate, the reinforcing frame is embedded in the panel. During the curing step, the at least one reinforcing frame can also be embedded on at least one surface of the at least one core layer. It is conceivable that due to the change in the crystallinity gradient, an inner shell layer is formed in the polymer matrix of the thermoplastic foamed substrate around the reinforcing frame. In the reinforcing frame, at least one inner shell layer may be formed around the fiber or non-fiber structure. The change in the crystallinity gradient may be due to the phase change from the amorphous state to the crystalline state. The network bonding layer can serve as the nucleation point for crystallization. When the thermoplastic core layer cools to the optimal crystallization temperature and begins to crystallize, it can preferentially nucleate at or near the network structure bonding layer, where the temperature is lower than the rest of the (foamed) melt and the melt strength is higher, so the crystallization rate is higher. This can result in the formation of a crystalline region and / or a higher density region near the reinforcing frame, thus leading to the formation of a region with higher crystallinity and / or density. Due to the formation of additional support on the polymer matrix, the panel is unexpectedly strengthened.

[0012] In addition, it is also conceivable to embed the at least one reinforcing frame on at least one surface of the core layer by an adhesive (such as but not limited to polyurethane (PU), epoxy resin, acrylic, cyanoacrylate (CA), polyvinyl acetate (PVA) adhesive). The reinforcing frame can also be hot-pressed or stamped into at least one surface of the semi-cured composite layer.

[0013] In another embodiment, the reinforcing frame is embedded within at least one core layer such that the surface energy of at least one core layer is altered. The change in surface energy aids in the adhesion of at least one surface of the core layer to paints, inks, glues, etc., thereby providing an unexpected improvement in the bonding and stability of the panel. This prevents paint or ink from peeling off and even prevents delamination between layers. In a preferred embodiment, the panel includes two reinforcing frames located on the upper and lower surfaces of the core layer.

[0014] In another embodiment, the presence of at least one reinforcing frame can alter the thermal conductivity of a crystalline and / or semi-crystalline thermoplastic foam substrate because during the curing process, heat is applied to melt and shape the thermoplastic material. Conceivably, the reinforcing frame can increase the thermal conductivity, which helps to more evenly distribute heat throughout the composite material. This affects the crystallization rate in different regions.

[0015] In a preferred embodiment, at least one reinforcing frame does not extend beyond the thickness of the core layer. However, in one embodiment, at least a portion of the front and / or rear surface of the core layer can be formed by a reinforcing frame that extends into the core layer thickness.

[0016] Advantageously, due to the presence of at least one reinforcing frame in the core layer, the strength of the panel is significantly increased. Several aspects of the panel can be measured. The American Society for Testing and Materials provides a standard test method ASTM D 1037-96 for evaluating the properties of wood fiber and particleboard materials. These include the modulus of elasticity in bending (MOE) and the modulus of rupture (MOR). Other useful tests included in ASTM D 1037-96 are the direct screw withdrawal test, hardness test, hardness modulus test, in-plane shear strength of the panel, glue line shear test, and falling ball impact test. If the panel is used as part of a furniture product, the ANSI / KCMA A161.1 cabinet furniture test can be particularly useful.

[0017] Preferably, the MOE of the reinforcing frame is not measured separately but is measured based on the flexibility of the core layer according to ASTM-D 1037-96 and / or ASTM D7031-11. If the core layer is made of a wood plastic composite (WPC), the average MOE ranges between 400 and 800 MPa, particularly between 500 and 700 MPa, such as 600 MPa, and more preferably 700 MPa, and even more preferably 800 MPa or higher if there is a reinforcing frame that increases the core stiffness.

[0018] In one embodiment, the panel according to the present invention can benefit from at least one core layer, which includes at least one support structure in addition to at least one reinforcement frame. According to the present invention, combining at least one support structure with at least one reinforcement frame results in a relatively robust core layer. The core layer can benefit from at least a portion of at least one support structure extending across the thickness of at least one core layer, thereby obtaining a robust and effective geometry. At least one support structure can thus form the skeletal structure of the panel. The support structure can also be referred to as the skeletal structure. Due to the use of at least one support structure extending across the thickness of at least one core layer, a relatively thin thermoplastic foam substrate can be used. The orientation of at least a portion of the support structure provides rigidity to the thermoplastic foam substrate. The panel of the present invention particularly has good rigidity and strength.

[0019] In the context of the present invention, the panel can be any panel suitable for decoration and / or construction. Thus, the panel can be a decorative panel and / or a structural panel. The panel according to the present invention can be configured for and / or suitable for, for example, furniture, shelves, doors, and can also be decorative and non-decorative building panels, floors, walls, and / or ceilings. For example, the panel can be a floor, a wall, or a ceiling. In the context of the present invention, when referring to a thermoplastic foam substrate, it can also refer to a porous substrate.

[0020] A non-limiting example of a porous material is, for example, a foamed material. Thus, the panel according to the present invention can include at least one at least partially foamed core layer. For example, it can be envisioned that the panel includes a foamed thermoplastic core layer, such as foamed PVC, foamed PET, foamed PP, and / or foamed WPC, a foamed thermosetting core layer, such as foamed TPU and / or PU foam, and / or a foamed inorganic core layer, such as including MgO, MgSO4, MgCl2, fiber cement, and / or aluminosilicate. It can also be envisioned that the panel includes an organic core layer, such as including cork, mycelium, etc. The core layer is preferably a waterproof core layer. The panel is preferably a waterproof panel.

[0021] It can be imagined that at least a part of the front surface and / or the rear surface of the core layer is also formed by at least one reinforcing frame. It can also be imagined that at least a part of at least one reinforcing frame extends throughout the thickness of the thermoplastic foamed substrate of at least one core layer. The panel and the substrate can have several possible shapes. For example, the panel and / or the substrate may be substantially plate-shaped. It can be imagined that the thickness of the core layer is substantially uniform throughout the core layer and / or along the length of the core layer. In this case, it is beneficial if the height of at least a part of the reinforcing frame is substantially equal to the thickness of the core layer. It can also be imagined that at least a part of at least one reinforcing frame extends at the minimum thickness of at least one core layer. The core layer can have a variable thickness. For example, it can be imagined that at least a part of at least one support structure forms a connection or a connection bridge between the front surface of the core layer and the rear surface of the core layer. It can be imagined that at least a part of at least one support structure is at an angle to the plane defined by the front surface and / or the rear surface of the core layer. An embodiment can be envisaged in which at least a part of at least one support structure is substantially perpendicular to the plane defined by the front surface and / or the rear surface of at least one core layer. When referring to the front surface and the rear surface, this can also be the first (side) surface and the second (side) surface. Specifically, it refers to the opposite sides of the panel. The panel of the present invention can be applied in multiple directions. Therefore, the terms "front" and "rear" should not be construed as restrictive. It is also possible to use, for example, upper and lower, first and second, main and secondary instead of front and rear. The upper side and the lower side, or the front side and the rear side, are generally the two opposite faces with the largest surface area and are used as the main decorative surfaces. For example, the panel is substantially rectangular. However, the panel according to the present invention can have any convenient shape. For example, it can be imagined that the panel is a cuboid or a hexahedron, especially comprising a plurality of faces.

[0022] The at least one core layer preferably may have a thickness of at least 3 mm. For example, it can be imagined that the thickness of at least one core layer is between 3 mm and 20 mm or between 5 mm and 16 mm, preferably between 6 mm and 8 mm or between 14 mm and 16 mm. An advantageous embodiment includes a core layer with a thickness in the range of 2.5 to 4 mm or in the range of 3.5 to 5 mm. In the case where the panel comprises a plurality of core layers, it can also be envisaged that the core layers have different thicknesses. For example, it can be imagined that the combined thickness of the core layers is between 3 and 12 mm. It can be imagined that the panel has a plurality of core layers, wherein at least one core layer has a thickness in the range of 0.5 to 1 mm and at least one other core layer has a thickness in the range of 1 to 3 mm. The panel may comprise at least three core layers adjacent to each other, wherein the central core layer is enclosed between the upper core layer and the lower core layer. It can be preferred that the upper core layer and / or the lower core layer have a greater thickness than the central core layer, and vice versa. For example, the thickness of at least one reinforcing frame can be substantially equal to the thickness of the core layer.

[0023] In one embodiment of the present invention, at least one reinforcing frame includes a plurality of ribs. In a further preferred embodiment, at least one rib, preferably at least two ribs, or more preferably each rib, extends across the thickness of at least one core layer. In this way, at least one rib or a plurality of ribs can form a reinforcing structure within the core layer, particularly within a thermoplastic foam substrate. It is also conceivable that at least one reinforcing frame includes a plurality of struts. When referring to ribs, it can also refer to struts, and vice versa. In a preferred embodiment, at least one rib of at least one reinforcing frame, preferably at least two ribs, more preferably each rib extends across the entire thickness of the thermoplastic foam substrate of at least one core layer. At least two ribs are preferably substantially parallel to each other. In this embodiment, good strength can be achieved by applying the ribs. The parallel orientation of the ribs can contribute to good stiffness of the core layer as well as the panel. It is possible that at least two ribs or a plurality of ribs extend substantially parallel across the entire thermoplastic foam substrate. For example, it can be imagined that at least two ribs are substantially parallel to each other in a direction substantially perpendicular to the length direction of the panel. In the case where the panel is an extruded panel, it is conceivable that at least two ribs are substantially parallel in a direction at an angle to the extrusion direction. For example, it is possible that at least two ribs are substantially parallel to each other in a direction substantially perpendicular to the extrusion direction. Optionally and / or additionally, at least two ribs can be defined in a triangular shape, for example, where the legs of the triangle extend from the front surface of the core layer to the back surface, or vice versa. It is also conceivable that at least two ribs are substantially parallel in a direction corresponding to the length direction of the panel.

[0024] In a possible embodiment, at least two ribs of at least one reinforcing frame can be interconnected. Thus, it is conceivable that at least one reinforcing frame is formed by interconnecting a plurality of substantially adjacent and / or parallel ribs. These ribs can form an interconnected network, thereby defining a reinforcing frame. It is also conceivable that at least two ribs are substantially isolated from each other. Thus, it is conceivable that at least one reinforcing frame is composed of a plurality of independent ribs. For example, a plurality of individual ribs can together form a reinforcing frame. It is also conceivable that the core layer includes a plurality of reinforcing frames. The orientation and / or position of at least one reinforcing frame and / or at least one rib (preferably a plurality of ribs) contributes to enhancing the rigid characteristics of the core layer.

[0025] In a possible embodiment of the panel according to the present invention, the panel comprises at least two core layers. For example, the panel may comprise at least two core layers, wherein each core layer comprises at least one thermoplastic foam substrate and / or at least one reinforcing frame. Thus, it is conceivable that the first reinforcing frame of the first core layer is arranged at an angle with respect to the second reinforcing frame of the second core layer. Each core layer may be any embodiment of the core layer described according to the present invention. For example, the panel may comprise at least two stacked or coupled core layers, wherein the at least two core layers comprise a plurality of ribs, particularly parallel ribs, wherein at least some of the ribs of the first core layer are arranged at an angle with respect to at least some of the ribs of the second core layer, preferably substantially perpendicular to at least some of the ribs of the second core layer.

[0026] Preferably, at least a part of the reinforcing frame is substantially rigid. In a further preferred embodiment, the reinforcing frame shown is a rigid support layer. It is also conceivable that the components defining the reinforcing frame are not themselves rigid, but their orientation and / or position results in the reinforcing frame having rigid characteristics. It is conceivable that at least a part of the reinforcing frame forms a lattice structure.

[0027] In a preferred embodiment, at least one core layer is an extruded core layer. In some embodiments, the extruded substrate comprises at least two materials extruded simultaneously. According to the present invention, the panel may also be an extruded panel. Extrusion is a preferred production method because it is relatively cost - competitive and enables continuous mass production.

[0028] The core layer can also be obtained by multi - layer extrusion. It is conceivable that the core layer or the thermoplastic foam substrate is composed of multiple materials. For example, at least one core layer may be composed of alternately arranged materials. For example, at least one core layer may comprise an alternating sequence of a first polymer material and a second polymer material, for example in a (-SPC - WPC -)*n configuration, where n is an integer ≥ 1.

[0029] In a possible embodiment, the panel according to the present invention comprises at least two decorative layers. It is conceivable that the first decorative layer adheres to the front surface of the core layer and / or the second decorative layer adheres to the rear surface of the core layer. It is also conceivable that there is another layer between at least one core layer and at least one decorative layer. The first decorative layer may be substantially the same as the second decorative layer. However, it is also conceivable that the first decorative layer is different from the second decorative layer. Any embodiment of the decorative layer described according to the present invention, if applicable, can be applied to the first decorative layer and / or the second decorative layer.

[0030] At least one core layer may include at least one side edge, and at least one decorative layer may be adhered to at least one side edge. In such an embodiment, the panel can be used, for example, for decorative purposes, and / or for furniture and / or for forming doors. Generally, in the panel according to the present invention, the surface area defined by the front surface and / or the rear surface is greater than the surface area defined by at least one side edge. It is conceivable that at least one decorative layer completely wraps the core layer. It is also possible to provide decorative layers on all side edges, including the front surface and the rear surface of the panel. For example, a (rectangular) block-shaped panel can have decorative layers provided on all six sides.

[0031] The panel according to the present invention, in particular the core layer thereof, may include a sealing edge. For example, the panel may include a sealing strip or a sealing layer, preferably applied by thermal lamination. The sealing layer can be thermally laminated to the outer edge of the core layer. This can prevent dirt accumulation or prevent moisture from being absorbed from the surrounding environment into the core layer. A separate sealing strip can be used. This embodiment can seal the thermoplastic foam substrate by heating, allowing for stronger structural integrity at the edges and providing support for screws, fastening devices, snap systems, and / or interlocking mechanisms.

[0032] In a preferred embodiment, the panel includes mating connecting elements and / or connecting parts. For example, it is conceivable that at least two side edges of the panel include mating connecting elements. For example, the connecting elements and / or connecting parts can be configured to provide a snap connection and / or a groove connection. For example, the connecting part of the panel can be an interlocking connecting part, preferably providing horizontal and vertical locking. An interlocking connecting part is a connecting part that requires elastic deformation, snapping, or multi-directional movement to couple or separate parts from each other. Any suitable interlocking connecting part known in the art can be applied. A non-limiting example is an embodiment in which the first side of the first pair of opposite sides includes a first connecting part, the second side of the first pair of opposite sides includes a complementary second connecting part, and the connecting parts allow multiple panels to be connected to each other; wherein the first connecting part includes a lateral tongue extending in a direction substantially parallel to the plane defined by the panel, and wherein the second connecting part includes a groove configured to receive at least a portion of the lateral tongue of another panel, and the groove is defined by an upper lip and a lower lip. It is conceivable that the connecting part or the snap assembly is thermoformed and / or milled.

[0033] When measured in the direction from the front surface to the rear surface of the core layer according to ASTM-D1037, the compressive strength of the reinforcement frame can be higher than the compressive strength of the thermoplastic foam substrate. Advantageously, this reinforcement frame increases the overall compressive strength of the core layer and the panel. This makes the panel stronger, more rigid, and less likely to break under pressure.

[0034] Preferably, at least one reinforcing frame and the thermoplastic foam substrate comprise the same compound, and the density of the reinforcing frame is higher than that of the thermoplastic foam substrate. This enables the reinforcing frame and the thermoplastic foam substrate to be bonded together without any adhesive, for example, by thermal lamination. The same compound is defined herein as substantially the same molecule. For example, both the reinforcing frame and the thermoplastic foam substrate can be made of polyvinyl chloride. However, the density of the thermoplastic foam substrate may be lower than that of the reinforcing frame because the thermoplastic foam substrate may contain more pores and / or have pores with a larger volume (i.e., a larger pore size). Due to the increased density of the reinforcing frame relative to the thermoplastic foam substrate, the reinforcing frame is stronger than the thermoplastic foam substrate, enabling the reinforcing frame to support the entire core layer. Therefore, the average pore volume of the thermoplastic foam substrate is preferably greater than that of the reinforcing frame. Optionally, the reinforcing frame may be substantially pore-free.

[0035] The reinforcing frame may comprise a thermoplastic polymer or a thermosetting polymer. A thermoplastic polymer is preferred because this enables the thermoplastic polymer to be heated before extrusion, thereby better controlling the viscosity of the extruded material. However, a thermosetting polymer is also possible.

[0036] The at least one reinforcing frame may comprise at least one polymer selected from the group consisting of polyvinyl chloride (PVC), polystyrene (PS), polyethylene (PE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), cross-linked polyethylene (XPE), polyurethane (PU), acrylonitrile butadiene styrene copolymer (ABS), polypropylene (PP), polyethylene terephthalate (PET), thermoplastic starch (TPS), cross-linked polystyrene (XPS), styrene acrylonitrile copolymer (SAN), polyphenylene oxide (PPO), polylactic acid (PLA), phenolic resin, melamine resin, formaldehyde resin, or any combination thereof. Preferably, the thermoplastic foam substrate and / or the reinforcing frame are at least partially biodegradable. Therefore, the preferred polymers are biodegradable. It is conceivable that the thermoplastic foam substrate comprises at least one bioplastic. It is also conceivable that the thermoplastic foam substrate and / or the reinforcing frame are made of bioplastic.

[0037] The above polymers can also be thermoplastic adhesives. The core layer preferably comprises at least one such thermoplastic adhesive. However, it is also conceivable that the core layer further comprises at least one additional or alternative thermosetting adhesive. The use of at least one thermoplastic or thermosetting material in the core layer is considered to impart flexible properties to the panel when necessary, for example, when flexibility is required to achieve the engagement of the locking mechanism.

[0038] The core layer and / or the reinforcement frame may include starch-based plastics, soy-based plastics, cellulose-based plastics, lignin-based plastics, and / or natural fibers. The biodegradability of these plastics makes them environmentally friendly panels, so that the panels can be biodegraded after the end of their life cycle.

[0039] The core layer may contain at least one filler. The material of the filler may include organic or inorganic materials, including but not limited to cellulose materials, fibrous materials, kraft paper, sawdust, wood chips, wood fibers, long wood fibers, short wood fibers, sand, lime, volcanic ash, plant fibers (such as mushroom fibers, cotton fibers, bamboo fibers, abaca fibers, pineapple fibers), magnesium compounds, magnesium oxide, magnesium carbonate, limestone, polymer fibers, glass fibers, carbon-based fibers, polymer particles, or hollow microspheres or particles with a particle size range of 1 to 1000 micrometers made of including but not limited to ceramics, glass, polymers, composites, or metals. Preferably, the core layer includes at least one filler selected from the following group: minerals (preferably calcium carbonate), pigments, modifiers, fibers (e.g., glass fibers, wood, straw, and / or hemp). The fibers can be loose fibers and / or interconnected fibers to form a woven layer or a non-woven layer. Preferably, the core layer further includes at least one additional filler selected from steel, glass, polypropylene, wood, acrylic, alumina, curaua, carbon, cellulose, coconut, cellulose, coconut, kevlar, nylon, perlon, polyethylene, PVA, asbestos, viburnum, and fique fibers. This can further increase the strength of the panel and / or the water resistance of the panel and / or the fire resistance of the panel. The core layer can be a wood-plastic composite layer.

[0040] The core layer preferably has a discrete density gradient. Preferably, compared with the average density of the core layer, the density of the thermoplastic foamed substrate is relatively low and relatively uniform. Preferably, compared with the average density of the core layer, the density of the reinforcement frame is relatively high and also relatively uniform. In particular, when the thermoplastic foamed substrate and the reinforcement frame contain the same compound and only the cell volume and number are different, the density gradient between the thermoplastic foamed substrate and the reinforcement frame is discrete. This ensures that the thermoplastic foamed substrate is very light, while the reinforcement frame is heavier and can withstand most of the loads applied to the panel.

[0041] According to the present invention, at least one core layer of the panel is preferably at least partially foamed. Within the scope of the present invention, different degrees of foaming can be envisaged. Preferably, the panel, in particular at least one core layer, has an expansion rate in the range of 5% to 50%. Non-limiting examples are expansion rates between 15% and 35%, in particular between 20% and 30%. However, it is also conceivable that the panel, in particular at least one core layer, has an expansion rate of at least 10%, preferably at least 20%, more preferably at least 30%, and even more preferably at least 40%. The expansion rate is in particular a measure of the volume change rate of the panel (especially the core layer) compared to the non-foamed melt.

[0042] At least one core layer may comprise at least one mineral filler, preferably selected from the group consisting of calcium carbonate (CaCO3), chalk, clay, calcium silicate (Si-Cal), dolomite, talc, magnesium oxide (MgO), magnesium chloride (MgCl or MOC cement), magnesium sulfate (MOS cement) and / or limestone. The purpose of using at least one mineral material in the core layer is to provide sufficient hardness to ensure the dimensional stability of the panel. For example, it is conceivable that the mineral material includes magnesium-based minerals, such as but not limited to magnesium oxide (MgO), magnesium chloride (MgCl or MOC cement), magnesium sulfate (also known as MOS cement). If limestone is used as the mineral filler, the mesh size of the limestone is preferably 325 mesh or 400 mesh. For example, the core layer may comprise a composite material in which the weight ratio of the mineral filler to the thermoplastic binder is at least 3:1. It is also conceivable that the weight ratio of the mineral filler to the thermoplastic binder in the composite material is greater than 3.5:1, or in the range of 3:1 to 4:1. However, optionally, it is also conceivable that the core layer contains at least 30% by weight of at least one mineral filler, preferably at least 50% (by weight), more preferably at least 60% (by weight). For example, the composite material contains at least 40% of the at least one thermoplastic binder, preferably at most 30% (by weight), more preferably at most 25% (by weight). It is conceivable that the ratio can also be smaller, such as 1:1, 1.5:1 or 2:1. The Vicat softening temperature of the core layer is at least 80 degrees Celsius, preferably at least 85 degrees Celsius, and / or the Shore D hardness of the front surface and / or the back surface of the panel is at least 85. Using at least one mineral material in the core layer can provide sufficient hardness, advantageously higher than 4000 MPa MOE and 22 MPa MOR, to ensure the dimensional stability and toughness of the panel. Using at least one polymer in the core layer is envisaged to impart flexible properties to the panel when necessary, or for example when flexibility is required to achieve the engagement of the locking mechanism. If used, the flexibility is preferably lower than 9000 Mpa and 36 Nm MOR. The core layer according to the present invention is particularly suitable for the thermo-bonding process. The composite material of the core layer may include, for example, at least one additive to increase the Vicat softening temperature. For example, at least one additive may include acrylonitrile styrene acrylate (ASA), acrylonitrile butadiene styrene (ABS), thermosetting systems and / or epoxy systems. At least one additive may also be a Vicat modifier or is referred to as a Vicat modifier. In another embodiment, at least one polymer of the composite material may be a thermosetting polymer.

[0043] In one embodiment, the thermoplastic foamed substrate and / or the reinforcing frame comprises a wood-plastic composite (WPC). These wood-plastic composites are aesthetically pleasing, so the decorative layer can be omitted.

[0044] The reinforcement frame can include stone plastic composite (SPC) and / or metal (such as aluminum). Like wood plastic composite, stone plastic composite is also aesthetically pleasing, so the decorative layer can be omitted. Metals such as aluminum can provide additional stability to the reinforcement frame while being relatively light in weight, thus forming a strong and lightweight panel.

[0045] Advantageously, the core layer and / or the panel are substantially free of adhesives. In particular, if the reinforcement frame and the thermoplastic foam substrate contain the same compound, there is no need to provide an adhesive layer between the two. In addition, in such a case, the extruded thermoplastic foam sheets can be bonded together by thermal lamination shortly after extrusion without the need to provide an adhesive. Adhesives typically release harmful volatile organic compounds. Therefore, not using adhesives is a great advantage. In particular, the panels can be connected together by complementary connecting means (such as tongues and grooves) without the need to use adhesives even when the panels are installed together to cover a larger surface area than a single panel.

[0046] The core layer can include at least one bio - based plasticizer, such as palm oil, epoxidized soybean oil, castor oil, succinic acid, citrate or any combination thereof. This gives the panel a certain degree of flexibility, which helps in the installation of the panel. In particular, if the panel has complementary connecting means, the connecting means can be more flexible, thus facilitating the connection of the panels.

[0047] According to the present invention, at least one decorative layer applied to the panel can include at least one support layer, such as at least one (high) filled thermoplastic support layer thermally laminated to a thermoplastic decorative layer, an optional wear - resistant layer, and an optional UV - coated finish. At least one decorative layer, in particular at least one support layer, can include or consist of SPC, LVT, extruded, calendered or injection - molded thermoplastics.

[0048] If applied, at least one decorative layer preferably comprises at least one support layer, at least one decorative layer and / or at least one protective layer. It is conceivable that, if applied, at least one decorative layer adheres to the core layer. It is also conceivable that the decorative layer is a printed layer. It is also imaginable that at least one decorative layer is a printed layer, especially a digital printed layer. The decorative layer can also be part of the support layer. In an advantageous embodiment of the panel, at least a part of the upper surface of the support layer is provided with at least one decorative pattern or decorative image. For example, such a decorative image or pattern can be provided by printing, for example by digital and / or inkjet printing. It is also possible to form at least one decorative pattern by embossing on the upper surface of the support layer or the panel. It is also conceivable that the decorative layer or the decorative layer is a separate layer, such as a high-pressure laminate (HPL), a veneer layer, a directly laminated paper layer and / or a tile. In a preferred embodiment, at least one decorative layer comprises a thermoplastic film or a cellulose layer. For example, the decorative layer can comprise a plurality of impregnated layers containing lignocellulose, as well as wood veneers, thermoplastic layers, stone veneers, veneer layers or similar materials and / or combinations of the above materials. The veneer layer is preferably selected from the group comprising wood veneers, cork veneers, bamboo veneers and the like. Other materials such as tiles or porcelain, natural stone veneers, rubber veneers, decorative plastics or vinyl plastics, linoleum and laminated decorative thermoplastics in the form of foils or films. It is conceivable that the support layer of at least one decorative layer is connected to the support structure of at least one core layer.

[0049] At least one decorative layer may comprise at least one thermoplastic material. For example, at least one support layer of the at least one decorative layer may comprise at least one thermoplastic material. The thermoplastic material may be PP, PET, RPET, PVC, PLA, PE, HDPE, LDPE, XPE or a bioplastic such as thermoplastic starch (TPS). For example, the design of the decorative layer may be selected from a design database that includes digitally processed designs, traditional patterns, picture or image files, custom digital artworks, random image patterns, abstract art, wood grain images, ceramic or concrete style images or user-defined patterns. These patterns may be printed or replicated using a laser printer, inkjet printer or any other digital printing means (including traditional printing methods). Various types of inks may also be used to meet the design requirements of the decorative layer. Preferably, the ink used in the printing method has, but is not limited to, properties such as water resistance, lightfastness, acid-free, metallic, gloss, glossiness, flash or deep black. Ideally, the decorative layer is visually exposed by a coating that is substantially transparent. The decorative layer may include a pattern, wherein the pattern is printed by digital printing, inkjet printing, gravure press, electronic line shaft (ELS) gravure press, automatic plastic printer, offset printing, flexographic printing or rotary printing press. The thickness of the decorative layer is preferably between 0.05 mm and 0.10 mm, for example approximately 0.07 mm. In a preferred embodiment, the decorative layer comprises at least one decorative layer and / or at least one wear-resistant layer. For example, the wear-resistant layer may be a scratch-resistant layer. The decorative layer may include a wear-resistant layer or a decorative surface layer, for example, a thermosetting varnish or varnish (such as polyurethane, PUR or melamine-based resin). In a preferred embodiment, the decorative layer comprises at least one substantially transparent wear-resistant layer or decorative surface layer. The wear-resistant layer may include one or more layers of transparent thermoplastic resin or thermosetting resin. Non-limiting examples of thermoplastic materials or thermosetting materials that may be used include polyvinyl chloride (PVC), polystyrene (PS), polyethylene (PE), polyurethane (PU), acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene terephthalate (PET), phenolic resin and / or melamine or formaldehyde resin. The wear-resistant layer may also be in the form of a liquid or paste made of a thermosetting resin (such as but not limited to phenolic resin and / or melamine or formaldehyde resin). The wear-resistant layer may include or consist mainly of an inherently scratch-resistant thermosetting resin-impregnated carrier layer (such as paper or wood cellulose). An advantage of the latter embodiment is that the urea-formaldehyde resin also functions as a relatively scratch-resistant wear-resistant layer. Generally, the thickness of the wear-resistant layer structure in the panel of the present invention is preferably in the range of 0.1 to 2.0 mm, more preferably between 0.15 and 1 mm, and even more preferably between 0.2 and 0.8 mm. The thickness of at least one support layer may be in the range of 0.2 to 2 mm, preferably 0.5 to 1.5 mm.This embodiment will provide sufficient body for the panel surface to obtain screw strength and / or screw pull-out strength. At least one support layer of at least one decorative layer is preferably substantially rigid. The rigid support layer can provide rigidity and strength to the panel. For example, according to EN 310 or according to ISO 24344 in a mandrel test of >100 mm, the stiffness or MOE of at least one support layer can be above 2000 Mpa, preferably above 4000 Mpa, more preferably above 6000 Mpa.

[0050] The decorative top layer, in particular its support layer, may optionally contain at least one filler. The materials of the filler of the decorative layer or its support layer can include organic or inorganic materials, including but not limited to cellulose materials, fibrous materials, kraft paper, sawdust, wood chips, wood fibers, long wood fibers, short wood fibers, sand, lime, volcanic ash, plant-based fibers (such as mushroom fibers, cotton fibers, bamboo fibers, abaca fibers, pineapple fibers), magnesium compounds, magnesium oxide, magnesium carbonate, limestone, polymer fibers, glass fibers, carbon-based fibers, polymer particles or hollow microspheres or particles with a particle size range of 1 to 1000 microns made of including but not limited to ceramics, glass, polymers, composites or metals. Preferably, the decorative layer or support layer includes at least one filler selected from the following group: minerals (preferably calcium carbonate); and pigments, modifiers, fibers (such as glass fibers, wood, straw and / or hemp). The fibers can be loose fibers and / or interconnected fibers to form a woven layer or a non-woven layer. Preferably, the decorative layer further includes at least one additional filler selected from the group consisting of steel, glass, polypropylene, wood, acrylic, alumina, curaua, carbon, cellulose, coconut, kevlar, nylon, perlon, polyethylene, PVA, asbestos, viburnum and fique fibers. This can further improve the strength and / or water resistance and / or fire resistance of the panel.

[0051] In a preferred embodiment, the wear-resistant layer or the decorative layer can include at least one coating. For example, at least one coating can include at least partially transparent or translucent protective coatings. In a preferred embodiment, at least one coating can be, for example, a polyurethane coating, an acrylic coating and / or an epoxy polyol coating. For example, such a coating can be an ultraviolet (UV) or electron beam (EB) curable coating. It can also be further contemplated that the coating includes a thermosetting resin and a photoinitiator crosslinked by a UV, excimer or electron beam curing process.

[0052] It can further be envisaged that at least one decorative layer comprises a tactile texture, preferably with a depth of at least 0.1 mm, more preferably at least 0.3 mm. Such a tactile texture can provide an enhanced visual effect. The enhanced visual effect can also be referred to as embossing. In a possible embodiment of the present invention, the texture or embossing can be provided during the production process by means of rotary or plate stamping. At least one wear layer (if applied) may carry an embossing with a surface texture design. The texture design can be any desired design, such as natural textures like wood, stone, etc. If a tactile structure is applied, it can have, for example, an irregular tactile texture. It can also be envisaged that only a part of at least one decorative layer has a tactile texture. In another possible embodiment, both the upper surface of the decorative layer and the surface of the chamfer can have a tactile texture, preferably with a depth of at least 0.1 mm. In particular when the decorative layer is produced by a lamination process, a single press can be used, which makes it cost-effective to use a press plate with a matching embossing for each decorative pattern in order to obtain a relief pattern on the top surface of the panel that matches the decorative pattern.

[0053] At least one decorative layer can further comprise at least one resin-impregnated paper layer containing at least one antibacterial agent, preferably zinc oxide (ZnO) and / or silver nanoparticles or the like. It can also be envisaged that the resin composition impregnating at least one paper layer contains at least one antibacterial agent, preferably a metal oxide such as titanium dioxide (TiO2), zinc oxide (ZnO) or isothiazolinone, zinc pyrithione, thiabendazole and / or silver nanoparticles. In cases where it is desired to apply a floor panel or a floor covering made from such panels to commercial, industrial or areas with high hygiene standards, the presence of at least one antibacterial agent can be beneficial. In the case of using a wear layer or a covering layer, the antibacterial agent can also be present in the wear layer or the covering layer. The antibacterial agent can be an integral part of the decorative layer. Panels with a decorative layer containing at least one antibacterial agent can generally better resist the invasion of bacteria, fungi, parasites and / or viruses compared to panels with the antibacterial agent covered.

[0054] It is beneficial to bond at least one decorative layer and at least one core layer together by means of heating and / or pressing. For example, at least one decorative layer and at least one core layer can be bonded by heat bonding and / or thermo-laminating. The advantage of using heat bonding is that the intermediate bonding layer between the decorative layer and the core layer can be omitted. The core layer and the decorative layer according to the present invention can employ a heat bonding process.

[0055] The present invention also relates to a method for manufacturing a panel, in particular a method for manufacturing a panel according to the present invention, comprising the following steps: a) extruding at least one mixture comprising at least one expandable thermoplastic material so as to form at least one thermoplastic foamed substrate; b) embedding at least one reinforcing frame into the thermoplastic foamed substrate so as to obtain a reinforced core layer; c) optionally, cooling at least a part of the core layer; d) adhering at least one decorative layer to at least one surface of at least one core layer. This method provides panels having all the advantages disclosed above.

[0056] Preferably, steps a) and b) are carried out substantially simultaneously. Advantageously, the extruded mixture is still in a high-temperature state. This makes it easier to embed the reinforcing frame into the thermoplastic foamed substrate, and due to the differences in temperature and / or melt strength, a reinforcing frame with a favorable density and / or crystallinity can be formed in the melt.

[0057] The adhesion in step d) can be a thermal lamination step. Thus, no separate adhesive is required.

[0058] The mixture may comprise at least one blowing agent, in particular supercritical CO2. This enables the mixture to foam effectively, thereby obtaining the thermoplastic foamed substrate of the panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The present invention will now be illustrated based on non-limiting exemplary embodiments shown in the following drawings. The drawings show:

[0060] Figure 1 a panel according to a first possible embodiment of the present invention;

[0061] Figure 2a and 2b 2c are panels according to embodiments of the present invention, wherein the reinforcing frames are located at different positions;

[0062] Figure 3a and 3b 3c, 3d, 3e and 3f show reinforcing frames according to different possible embodiments of the present invention;

[0063] Figure 4a and 4b 4c and 4d show exploded side views of panels according to possible embodiments of the present invention;

[0064] In these drawings, the same reference numerals refer to similar or equivalent technical features or elements. DETAILED DESCRIPTION

[0065] Figure 1Shows a first possible embodiment of the panel 100 of the present invention. The panel 100 includes a composite layer 101 and a decorative layer 105. The decorative layer 105 is adhered to the composite layer 101, particularly to the upper surface of the composite layer 101. The composite layer 101 includes a thermoplastic foam substrate 103 and embedded first and second reinforcement frames 102a and 102b. The composite layer 101 includes an upper surface 101a and a lower surface 101b on opposite sides of the composite layer 101, where the decorative layer 105 is adhered to the upper surface 101a. The first reinforcement frame 102a is located near the upper surface 101a of the composite layer 101, while the second reinforcement frame 102b is located near the lower surface 101b of the composite layer 101. Both reinforcement frames 102a, 102b are embedded in the composite layer 101 off-center. The panel further includes a coating 104 on top of the decorative layer 105, and the panel further includes a connecting element 107 that is part of the composite layer 101.

[0066] Figures 2a to 2c Shows embodiments of the panels 200, 300, and 400 of the present invention. Figure 2a Shows a panel 200 similar to the Figure 1 panel 100. The panel 200 includes a reinforcement frame 202 located near the top of the composite layer 201 within the composite layer 201. The decorative layer 205 is located on top of the composite layer 201. Figure 2a Further shows a portion of the panel surrounded by a dashed line and enlarged within the circle 206. It can be seen that the reinforcement frame 202 is a network structure embedded in the thermoplastic foam substrate 203. Figure 2b Shows a panel 300, where the reinforcement frame 302 includes a network structure that is located near the bottom of the panel 300 and thus also near the bottom of the composite layer 301. Figure 2b Further shows a portion of the panel 300 surrounded by a dashed line and enlarged within the circle 306. The panel 300 also includes a decorative layer 305. Finally, Figure 2c Shows a panel 400 that includes an upper reinforcement frame 402a and a lower reinforcement frame 402b. Both reinforcement frames 402a, 402b are embedded in the composite layer 401 off-center. The upper reinforcement frame 402a is embedded in the composite layer 401 near the decorative layer 405. The lower reinforcement frame 402b is embedded in the composite layer 401 near the bottom of the panel 400. Similarly, the reinforcement frames 402a, 402b have a network structure as shown by the enlarged portion in the circle 406. The thermoplastic foam substrate 403 is located between the decorative layer 405 and the upper reinforcement frame 402a, between the upper reinforcement frame 402a and the lower reinforcement frame 402b, and below the lower reinforcement frame 402b.

[0067] Figures 3a to 3f Shows different types of reinforcement frames 102. Figure 3ashows a reinforced frame 102 with uniformly distributed pores, while Figure 3d shows a similar reinforced frame 102 with more uniformly distributed pores. The pores can also be randomly distributed, as shown in the Figure 3c reinforced frame shown. A reticulated structure, a wavy structure, and large openings are also possible, as shown in the Figures 3d to 3f reinforced frame 102 in

[0068] Figure 4a , 4b , 4c and 4d show exploded side views of panels 500, 600, 700, and 800 according to possible embodiments of the present invention. The panels are optionally equipped with connecting components.

[0069] Figure 4a and 4b show panels 500 and 600, which include composite layers 501, 601. The composite layers 501, 601 include thermoplastic foam substrates 503, 603 and reinforced frames 502, 602. In the Figure 4a panel 501, the reinforced frame 502 is located at the upper part of the composite layer 501, while Figure 4b the reinforced frame 602 of the panel 600 in

[0070] Figure 4c and 4d show panels 700, 800, which include composite layers 701, 801. The composite layers 701, 801 include thermoplastic foam substrates 703, 803. Both panels 700, 800 include an upper reinforced frame 702a, 802a embedded in the thermoplastic foam substrates 703, 803 (near the upper part of the composite layers 701, 801), and a lower reinforced frame 702b, 802b embedded in the thermoplastic foam substrates 703, 803 (near the lower part of the composite layers 701, 801). Figure 4d The panel 800 in Figure 4c lacks the decorative layer 705 present in the panel 700 in Figure 4d . The panel 800 in

[0071] has a support layer 808 to reinforce the panel 800. Both panels include coatings 704, 804 as the top layer, and connecting components 707, 807.

[0072] The verb “comprise” and its variations used in this patent publication are understood not only to mean “include,” but also to denote the phrases “contain,” “consist essentially of,” “consist of” and their variations.

Claims

1. A panel, characterized in that, The panel comprises: at least one core layer, in particular at least one composite core layer, the core layer comprising: · at least one thermoplastic foamed substrate; and · at least one reinforcement frame; and at least one decorative layer adhered to at least one surface of the at least one core layer; wherein the at least one core layer comprises a front surface and a rear surface on opposite sides, and wherein the at least one reinforcement frame is embedded within the at least one core layer such that, when viewed from the front surface and / or the rear surface of the at least one core layer, at least a portion of the outer periphery of the at least one reinforcement frame is located below 20% of the thickness of the core layer.

2. The panel according to claim 1, wherein, The at least one reinforcement frame is encapsulated within the at least one core layer, in particular within the at least one thermoplastic foamed substrate; and / or, wherein an inner shell layer is formed around at least a portion of the at least one reinforcement frame such that at least a portion of the at least one reinforcement frame is encapsulated within the at least one core layer by the inner shell layer, in particular within the at least one thermoplastic foamed substrate.

3. The panel according to claim 1 or 2, wherein, At least a portion of the outer periphery of the at least one reinforcement frame is substantially parallel to the front surface and / or the rear surface of the at least one core layer, and / or, wherein at least a portion of the at least one reinforcement frame extends in the thickness of the at least one core layer, in particular in the thickness of the at least one thermoplastic foamed substrate.

4. The panel according to any one of the preceding claims, wherein, At least a portion of the at least one reinforcement frame is defined by a honeycomb and / or double-wall and / or grid and / or mesh and / or strip and / or cloth and / or wire structure.

5. The panel according to any one of the preceding claims, wherein, At least a portion of the at least one reinforcement frame comprises at least one of the following materials: aluminium, steel, brass, bronze, rigid thermoplastic composite, rigid thermosetting composite, stone plastic composite (SPC) or any combination thereof.

6. The panel according to any one of the preceding claims, wherein, At least a portion of the at least one reinforcement frame is positioned at an angle with respect to the plane defined by the front surface and / or the rear surface of the at least one composite layer.

7. The panel according to any one of the preceding claims, wherein, The at least one core layer comprises at least two reinforcement frames, wherein a first reinforcement frame is spaced apart from at least one second reinforcement frame, preferably, wherein at least one first reinforcement frame is arranged at an angle with respect to at least one second reinforcement frame.

8. The panel according to any one of the preceding claims, wherein, The panel comprises at least one decorative layer, in particular at least one digitally printed decorative layer.

9. The panel according to any one of the preceding claims, wherein, The at least one core layer is an extruded layer, and / or, wherein the at least one thermoplastic foamed substrate is an extruded substrate.

10. The panel according to any one of the preceding claims, wherein, The at least one core layer comprises at least one side edge, and wherein the at least one decorative layer is adhered to the at least one side edge.

11. The panel according to any one of the preceding claims, wherein, The panel comprises complementary connecting components.

12. The panel according to any one of the preceding claims, wherein, Measured in the direction from the front surface to the rear surface of the core layer according to ASTM-D1037, the compressive strength of the at least one reinforcement frame is higher than the compressive strength of the at least one thermoplastic foamed substrate.

13. The panel according to any one of the preceding claims, wherein, The average cell volume of the at least one thermoplastic foamed substrate is greater than the average cell volume of the at least one reinforcement frame.

14. The panel according to any one of the preceding claims, wherein, The at least one thermoplastic foam substrate and / or the at least one reinforcing frame comprises at least one polymer selected from polyvinyl chloride (PVC), polystyrene (PS), polyethylene (PE), high density polyethylene (HDPE), low density polyethylene (LDPE), cross-linked polyethylene (XPE), polyurethane (PU), acrylonitrile butadiene styrene copolymer (ABS), polypropylene (PP), polyethylene terephthalate (PET), thermoplastic starch (TPS), cross-linked polystyrene (XPS), styrene acrylonitrile copolymer (SAN), polyphenylene oxide (PPO), polylactic acid (PLA), phenolic resin, melamine resin, formaldehyde resin or any combination thereof.

15. The panel according to any one of the preceding claims, wherein, The density of the at least one thermoplastic foam substrate has a density gradient.

16. The panel according to any one of the preceding claims, wherein, The density range of the at least one thermoplastic foamed substrate is 80 to 1000 kg / m 3 , preferably 100 to 1000 kg / m 3 , more preferably 300 to 1000 kg / m 3 , for example about 600 kg / m 3 .

17. The panel according to any one of the preceding claims, wherein, The at least one thermoplastic foam substrate and / or the at least one reinforcing frame comprises wood plastic composite (WPC) and / or foamed thermoplastic.

18. The panel according to any one of the preceding claims, wherein,The at least one core layer is substantially free of adhesives, preferably the panel is substantially free of adhesives.

19. A method for preparing a panel, in particular a panel according to any one of claims 1 to 18, the method comprising the steps of: a) Extruding at least one mixture comprising at least one expandable thermoplastic material to form at least one thermoplastic foam substrate; b) Embedding at least one reinforcing frame into the thermoplastic foam substrate to obtain a reinforced core layer; c) Optionally, cooling at least a portion of the core layer; d) Adhering at least one decorative layer to at least one surface of at least one core layer.

20. The method according to claim 19, wherein, The adhesion in step d) is a thermal lamination step, and / or, wherein the mixture comprises at least one blowing agent, in particular supercritical CO2.

Images