Method and apparatus for manufacturing plate element comprising cavity

Abstract

The present disclosure relates to a method for manufacturing a plate element comprising at least one cavity (2) on its rear face. The method comprises: providing a substrate (3) comprising a thermoplastic material, wherein the substrate comprises a substrate portion (3a); and creating said at least one cavity on the back side (3b) of the substrate by embossing the substrate portion via an embossing device (10) comprising at least one protruding embossing element (9), thereby obtaining said plate element. When the at least one cavity is created, the substrate portion is placed at an elevated temperature (TS) of 40-295 DEG C. The method comprises forming at least one conical cavity by means of at least one conical embossing element.

Description

Technical Field

[0001] The present disclosure generally relates to a method for manufacturing a panel element, which panel element comprises at least one cavity, preferably a plurality of cavities, on the back side of the panel element. More specifically, the cavity is created by means of embossing. The panel element may be formed from a substrate comprising a thermoplastic material. The present disclosure also relates to the panel element itself, such as a panel, and to related equipment for manufacturing the panel element. The panel may be a building panel, a floor panel, a wall panel, a ceiling panel or a furniture component. Background Art

[0002] The weight of panels such as floor panels can be reduced in various ways. WO 2013 / 032391 and WO 2014 / 007738 disclose panels comprising thermoplastic material, which are provided with a specific groove structure on the back side thereof for reducing its weight. The groove structure can be formed by removing material from the back side, for example by removing material with a rotating jumping tool or jumping cutter. Improved methods for forming such grooves by machining tools are disclosed, for example, in WO 2020 / 180237 and WO 2022 / 050891.

[0003] There may be situations where it is advantageous to form the grooves without removing any material. For example, as disclosed in WO 2013 / 032391, the grooves may be formed when pressing the panel, for example in a discontinuous press, by pressing as disclosed in WO 2021 / 018918 or by embossing as disclosed in WO 2021 / 180882. However, to date, little is known about the details of this and similar methods. Furthermore, the final properties of the panel comprising the grooves formed by this and similar methods remain to be further developed / improved. Therefore, there is a need for improved methods and apparatus for providing such grooves or cavities. Summary of the invention

[0004] It is therefore an object of at least embodiments of the present disclosure to provide a more efficient method for manufacturing a plate element comprising a cavity.

[0005] It is another object of at least embodiments of the present disclosure to provide a more controllable method for creating a cavity.

[0006] It is a further object of at least embodiments of the present disclosure to provide attachment of a layer to a plate element comprising a cavity in a more controlled manner.

[0007] Another object is to provide a corresponding apparatus for producing a plate element.

[0008] Another object is to provide a board element or panel comprising at least one cavity on its back side, optionally manufactured according to an embodiment of the method described herein.

[0009] These and other objects and advantages that will become apparent from the description have been achieved through the various aspects, embodiments and examples described below.

[0010] According to a first aspect of the present disclosure, a method for manufacturing a plate element is provided, the plate element comprising at least one cavity, preferably a plurality of cavities, on the back side of the plate element. The method comprises providing a substrate comprising a thermoplastic material, wherein the substrate comprises a substrate portion, and creating the at least one cavity on the back side of the substrate by embossing the substrate portion by means of an embossing device comprising at least one protruding embossing element, preferably a plurality of protruding embossing elements, thereby obtaining the plate element.

[0011] These cavities can reduce the weight of the plate element. According to a first aspect, the cavities can be created from the substrate by shaping the thermoplastic material in the substrate, preferably when the substrate portion is placed at an elevated temperature. In fact, by embossing, the material can be displaced to create the cavities. In particular, to create the cavities, a smaller amount of material can be removed from the substrate, for example by a rotating cutting device, or even no material can be removed, whereby the method can become more efficient.

[0012] The base plate may be hardened or cured to form at least a portion of the plate element, preferably a core thereof.

[0013] For example, when the substrate is provided, the substrate may be free of cavities. However, in some embodiments, the preformed substrate may include recesses as described in detail below.

[0014] Throughout this disclosure, the term "cavity" may be interpreted as a recess, a groove, a depression, a notch, a notch, a cutout, etc. The cavity may be open toward the back side.

[0015] To simplify the description herein, reference will generally be made to a plurality of cavities, a plurality of stamping elements, etc., but it is clear to the skilled person that at least one cavity, at least one stamping element, etc. is encompassed by these statements.

[0016] The hardened or cured substrate may provide the core of the board element. Optionally, a decorative structure such as a decorative layer and / or a wear layer may be attached such as laminated or adhered to the front side of the substrate or core. The decorative layer may be a printed layer. In some embodiments, a backing layer such as a balancing layer may be attached such as laminated or adhered to the back side of the substrate or core.

[0017] Thermoplastic materials may include thermoplastic polymers, such as polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), thermoplastic polyurethane (TPU), or polyethylene terephthalate (PET), ethylene-vinyl acetate copolymer (EVA), polyamide (PA), polystyrene (PS), polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), polyvinyl butyral (PVB), polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), polyacrylamide (PAM), polybutylene terephthalate (PBT), or chlorinated PVC (CPVC). Generally herein, thermoplastic materials may include amorphous polymers and / or semi-crystalline polymers.

[0018] The thermoplastic material may include a filler, preferably an inorganic filler or an organic filler. The content of the filler may be more than 40 wt%, preferably more than 60 wt%, for example 50-90 wt% or 60-80 wt%.

[0019] The filler may include or may be an inorganic filler such as a mineral material, for example calcium carbonate (CaCO3), limestone such as chalk, talc, fly ash, or a stone such as rock powder.

[0020] The filler may include or may be an organic filler, such as wood material, bamboo material, cork or rice husk. For example, the wood material may be wood fiber and / or wood chips, and the bamboo material may be bamboo chips.

[0021] The amount of thermoplastic polymer, such as PVC, may be 10-40 wt%, for example 15-35 wt%.

[0022] The core may be a rigid core. The content of plasticizer in the core may be less than 5 wt%, preferably less than 3 wt% or less than 1 wt%. The core, such as a rigid core, may have an elastic modulus or Young's modulus E of preferably 1-10 GPa, for example 2-8 GPa, measured according to ISO 178:2010 / A1:2013.

[0023] The embossing device may comprise at least one roller. Thus, the substrate may be embossed while the substrate is displaced.

[0024] The embossing device may comprise an embossing platen provided with a structured surface comprising the at least one protruding embossing element.The embossing platen may be arranged in a static press or in a continuous press.

[0025] The first and second groups of the embossing elements are separated from each other along a separation direction by a blank portion, and the distance between the embossing elements along the separation direction between the first group and the second group is greater than the distance between the embossing elements in each of the first group and the second group. Therefore, a plurality of cavities separated by the separation portions can be created in the plate element. The separation portions can be used as dividing portions or reinforcing plate areas of the plate element. The blank portion may be free of any embossing elements, for example, a smooth surface. However, the blank portion may optionally include an embossing element, which is preferably smaller than the embossing element in height and / or extension length, for example, 50% smaller, preferably 70% smaller, and more preferably 90% smaller than the embossing element. At least during a portion of the embossing cycle, the separation direction may be substantially parallel to the feed direction. The separation direction of the roller of the embossing device may extend along and / or transversely to the direction of rotation of the roller.

[0026] When creating the at least one cavity, the substrate portion may be placed at an elevated temperature. Thus, the creation of the cavity may become more controlled and / or the flow of material may be increased when creating the cavity.

[0027] When creating the at least one cavity, the substrate portion, for example as a whole, may be provided at a temperature above / above the glass transition temperature Tg of the thermoplastic material. Thus, the thermoplastic material may be provided in a viscoelastic state (rubbery state). When the thermoplastic material comprises a semi-crystalline polymer (e.g. PET), the substrate portion is preferably provided at a temperature below / below the melting temperature Tm of the thermoplastic material.

[0028] The method may further comprise raising the temperature of the substrate portion from the initial temperature to an elevated temperature. The elevated temperature may be higher than the ambient temperature in which the substrate is provided during cavity creation and / or higher than the initial temperature of the substrate. For example, the ambient temperature may be 13-40°C, such as 16-26°C.

[0029] The initial temperature may be the temperature of the substrate that has been adapted to the ambient temperature. Alternatively or additionally, the initial temperature may be the temperature of the substrate before heating the substrate.

[0030] For example, the temperature of the (portion of) the substrate, such as the initial temperature or the elevated temperature, may be determined by an infrared thermometer or a thermal imaging camera.

[0031] The elevated temperature may be obtained by heating the substrate portion. Thus, the substrate portion may be preheated prior to creating the cavity.

[0032] Said elevated temperature may be obtained during the formation of the substrate under heating and preferably also under pressure.Thus, the heat generated for forming the substrate may be used to simplify the creation of the cavity therein.

[0033] The elevated temperature may exceed 40°C, preferably 40-295°C, more preferably 100-295°C. When the thermoplastic material comprises PVC and preferably also comprises a filler, the elevated temperature may be 50-210°C, preferably 60-180°C, more preferably 110-180°C. When the thermoplastic material comprises PP and preferably also comprises a filler, the elevated temperature may be 60-220°C, preferably 70-175°C, more preferably 100-175°C. When the thermoplastic material comprises PET and preferably also comprises a filler, the elevated temperature may be 70-295°C, preferably 110-280°C, more preferably 130-280°C.

[0034] Embossing may comprise applying a pressure of 0.4-5.0 MPa, such as 0.5-4.0 MPa or 0.6-3.0 MPa, to the substrate portion. For example, the pressure may be a maximum applied pressure.

[0035] The method may further comprise forming the substrate under heating and preferably also under pressure and / or by (co)extrusion. "(Co)extrusion" refers throughout the disclosure to extrusion in an extruder (single layer) or coextrusion in a coextruder (at least two layers). In this document, an extruder or a coextruder may be referred to as a "(co)extruder" or sometimes just "extruder".

[0036] The method may further comprise cooling the front side of the substrate during and / or after creating the at least one cavity. By cooling, a well-defined and uniform front side may be provided, while shrinkage of the thermoplastic material may occur in a lower portion of the substrate, such as the back side. An inner portion of the at least one cavity may constitute a non-functional surface and may serve as a compensation area for material that shrinks during cooling.

[0037] The method may also include cooling at least the cavity region of the substrate or plate element during and / or after creating the at least one cavity. For example, the cavity region may be cooled from the elevated temperature to a cooling temperature lower than the elevated temperature. Therefore, the form of the cavity may become more defined, such as being fixed in a shorter period of time. In addition, the dimensional stability of the plate element may be improved, and therefore, the attachment (e.g., lamination) of the layer to the plate element including the cavity may become more controllable. When the thermoplastic material includes a semi-crystalline polymer, cooling the cavity region during cavity creation may be particularly useful, and the semi-crystalline polymer may be more susceptible to warping or deformation, such as due to the shrinkage of the material during cooling. In general, in this article, the cavity region may include a substrate portion, or a corresponding plate portion obtained after it is solidified or hardened, and / or a section of the created cavity, such as an inner portion of the cavity or its cavity wall and / or bottom wall, and preferably also a surface section between the cavities.

[0038] When both the front side and the cavity region are cooled, the front side is preferably cooled to a lower temperature than the cavity region.

[0039] The cavity region may be cooled to a cooling temperature Tc in the range of 0.8 to 1.9 times the glass transition temperature Tg of the thermoplastic material. The cooling temperature Tc and the glass transition temperature Tg may be expressed in Kelvin. The thermoplastic material may include an amorphous polymer and / or a semi-crystalline polymer. For example, the thermoplastic material may include PVC, PET, PA, PS, or PVAc.

[0040] Substrate portions or even the entire substrate may be placed at the substrate formation temperature directly after substrate formation.In some embodiments, the cavity region may be cooled to below the substrate formation temperature.

[0041] Typically, the cavity region may be cooled from the elevated temperature by at least 20°C, preferably 20-120°C. For example, such cooling may be preferred for semi-crystalline polymers such as PET. For amorphous polymers such as PVC, the cavity region may be cooled by at least 30°C, preferably 30-90°C.

[0042] In some embodiments, the cavity region may be cooled from the elevated temperature by at least 10°C, preferably 10-100°C lower, to a temperature below the melting temperature Tm of the thermoplastic material. Such cooling may be preferred for semi-crystalline polymers. For example, the thermoplastic material may include PP, PE, TPU or EVA.

[0043] The method may further comprise attaching the layer to the plate element, for example by lamination or with the aid of an adhesive.Lamination may comprise laminating the layer to the plate element, optionally under heating.

[0044] The method may also include supporting at least an inner portion of at least one of the created cavities during lamination of the layers onto the plate element and / or during cooling of at least the cavity region of the plate element. Alternatively or additionally, the inner portion may be supported during pressing between rollers. Similar to the discussion above, the form of the cavity may thereby become more defined. Furthermore, lamination may be better controlled, for example, by reducing the risk of deforming or even destroying the created cavity. Indeed, the pressure applied by lamination may sometimes lead to at least partial collapse of the cavity. Furthermore, due to the varying pressure distribution in the plate element caused by the created cavity, the risk of obtaining discolorations or defects in the layer may be reduced.

[0045] This layer may be a decorative structure and / or a backing layer.

[0046] In some embodiments, the layers can be attached (eg, laminated) to the substrate at the same time as the cavity is created.

[0047] The plate element may be cooled after creating the cavity and before laminating the layers.

[0048] The method may further include forming at least one chamfer in at least one cavity, wherein each chamfer is disposed between a cavity wall and a back surface or between a cavity wall and a cavity bottom.

[0049] The method may further comprise creating at least one tapered cavity by means of at least one tapered stamping element. Thus, the at least one protruding stamping element may be a tapered stamping element, and the tapered stamping element may create a tapered cavity. The tapered stamping element may provide a draft angle. For example, the tapered stamping element may comprise a tapered sidewall portion and / or a chamfer, and the tapered cavity may comprise a tapered cavity wall and / or a chamfer. Thus, after creating the cavity, the substrate material may be more easily released from the stamping element. Furthermore, when creating the cavity, the flow of the material may become better, particularly when the substrate portion is exposed to an elevated temperature.

[0050] The draft angle between the sidewall portion of the at least one tapered embossing element and the substantially normal direction / overall normal direction of the embossing device may exceed 0.5°, such as exceed 1.0°, or even exceed 3.0°.

[0051] The method may further comprise moving the substrate in a feed direction, preferably moving the substrate in a feed direction during creation of the at least one cavity.

[0052] The method may further comprise preforming the substrate, preferably by forming at least one groove, before creating the at least one cavity. Thus, the substrate may be provided with at least a part of the final cavity configuration of the plate element. Furthermore, an expansion area for material displaced during embossing may be provided, whereby the creation of the cavity may be simplified and / or the control of material displacement during embossing may be improved. For example, the preforming may be obtained by (co)extrusion.

[0053] The cavity may be created after pre-forming of the substrate when the substrate portion is exposed to an elevated temperature.

[0054] The panel element can be provided in the form of a panel or can be divided into at least one panel, for example at least two panels, wherein each panel is a building panel, a floor panel, a wall panel, a ceiling panel or a furniture component. For example, planks, slabs and tiles are examples of panels.

[0055] The creation of the cavity may comprise displacing the material laterally, which may result in a change in the width of the substrate. Thus, the method may further comprise trimming an edge portion of the substrate after the creation of the cavity. Trimming may provide a more defined width of the plate element. Preferably, the edge portion is trimmed when the substrate is exposed to an elevated temperature, e.g. according to any of the embodiments described herein. Thus, easier trimming may be provided, while more efficient use of the energy used to heat the substrate may be provided.

[0056] The method may further comprise annealing the plate element after creating the at least one cavity. By annealing (or "normalizing"), internal stresses in the plate element, for example after creating the cavity, may be reduced. This may be particularly important in sharp sections or corners of the cavity, where internal stresses may be particularly high. For example, annealing may be performed after dividing the plate element into plate members and before further dividing the plate members into at least two panels. Thus, the dimensional stability of the panels may be increased.

[0057] According to a second aspect of the present disclosure, there is provided a board element, such as a panel, obtainable by a method according to any embodiment of the first aspect.

[0058] According to a third aspect of the present disclosure, there is provided an apparatus for manufacturing a plate element comprising at least one cavity, preferably a plurality of cavities, wherein the apparatus comprises an embossing device comprising at least one embossing element.

[0059] The apparatus may further comprise a substrate heating device and / or a cooling unit, which is preferably arranged downstream of the substrate heating device.

[0060] The apparatus may further comprise a substrate forming arrangement.

[0061] The substrate forming arrangement may comprise a (co)extruder and preferably also a roller assembly.

[0062] A substrate heating device may be provided in the substrate forming arrangement.

[0063] The substrate heating device may be a separate heating device.

[0064] The substrate forming arrangement may include a pressing device, such as a continuous press or a static press. The continuous press may be a double belt press. The static press may be a multi-layer press or a short cycle press.

[0065] The embossing device may comprise at least one roller.

[0066] The embossing device may comprise an embossing platen provided with a structured surface comprising protruding embossing elements.

[0067] The apparatus may also comprise a continuous press, such as a double belt press, or a static press, such as a multi-day press or a short cycle press.

[0068] The apparatus may further comprise a preforming device.

[0069] The apparatus may further comprise a plate dividing device configured to divide the plate element into at least one, for example at least two panels.

[0070] The apparatus may further comprise a support member adapted to support at least an inner portion of the at least one cavity of the plate element.

[0071] The apparatus may further comprise an annealing unit.

[0072] According to a fourth aspect of the present disclosure, a panel is provided, comprising at least one layer comprising a thermoplastic material, wherein the panel comprises at least one cavity, preferably a plurality of cavities, on the back side of the panel. The cavity may be an embossed cavity. However, in some embodiments, the cavity may be created by removing material from the back side.

[0073] The at least one cavity may be tapered. The cavity wall may be inclined relative to a normal direction of the substrate at a wall angle exceeding 0.5°, such as exceeding 1.0° or even exceeding 3.0°. Alternatively or additionally, the tapered cavity may comprise a chamfer.

[0074] The at least one cavity can be arranged in an inner region of the rear side.

[0075] The panel may be rectangular and the at least one cavity may intersect at least a portion of a locking device provided on a long edge portion and / or a short edge portion of the panel. Thus, less precise cavity positioning may be required and manufacture of the plate element may be simplified.

[0076] Any, some or each layer may comprise a thermoplastic material including a thermoplastic polymer such as PVC and preferably also a filler.

[0077] The surface of the interior portion of the at least one cavity may be closed ("closed" is defined elsewhere herein).

[0078] The at least one cavity may be elongated, and the ratio between its longitudinal extension and transverse extension may be 1<LE / TE≤150, such as 6≤LE / TE≤120, preferably 10≤LE / TE≤100.

[0079] The at least one cavity may have substantially the same extension along a pair of non-parallel, eg perpendicular, horizontal directions.

[0080] For the depth of the cavities, the depth of the cavities at the long edge portions and / or short edge portions of the panel is smaller than the depth of the cavities in the interior of the back side. Thus, the locking device can become stronger and / or a more rigid board element section can be provided.

[0081] A first group and a second group of cavities are separated from each other by a partition along a panel direction, wherein an inter-cavity distance between the first group and the second group along the panel direction is greater than an inter-cavity distance within each of the first group and the second group.

[0082] The panel may further comprise a backing layer, such as a balancing layer, wherein the backing layer is continuous at least at the location of the at least one cavity. By being continuous, the backing layer may be complete / unbroken, e.g. without any holes passing through it. Thus, the effect of the backing layer, e.g. the effect of balancing the panel, may be improved or even maintained.

[0083] Embodiments and examples of the second, third and fourth aspects are largely similar to those of the first aspect and reference is hereby made to them.

[0084] In addition, the board element or panel according to any of the first, second, third or fourth aspects can be a luxury vinyl tile (LVT tile), a stone plastic (polymer) composite panel or a solid polymer core panel (SPC panel), or an expanded polymer core panel (EPC panel), also known as a waterproof core panel or a wood plastic composite panel (WPC panel).

[0085] Generally, unless otherwise expressly defined herein, all terms used in the claims and the following embodiments are to be interpreted according to their ordinary meaning in the technical field. Unless otherwise expressly stated, all references to "a / an / the / said [element, device, component, mechanism, step, etc.]" should be openly interpreted as referring to at least one example of the element, device, component, mechanism, step, etc. References to one or more "at least one element" etc. may be referred to simply as "element". BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The present disclosure will be described in more detail below in conjunction with exemplary embodiments and with reference to the accompanying exemplary drawings, in which:

[0087] Figure 1a-1c 2a-2b show in side view an embodiment of an apparatus for manufacturing a plate element comprising a cavity and its use.

[0088] Figure 2c-2f An embodiment of an imprinting device is shown in side view.

[0089] Figure 3a-3eAn embodiment of an apparatus including an imprinting device and its use are shown in a side view ( Figure 3a-3c and 3e), and can be used, for example, Figure 3c Embodiment of the stamping member in the embodiment of Figure 3d ).

[0090] Figures 4a-4f In perspective ( Figure 4a ) and side view ( Figure 4b ) shows an embodiment of the imprinting device, in a perspective view ( Figure 4c ) and sectional side view ( Figure 4d ) shows an embodiment of the stamping member, and a perspective view ( Figure 4e ) and side view ( Figure 4f ) shows a schematic implementation scheme of the stamping member.

[0091] Figure 5a-5b In perspective ( Figure 5a ) shows an embodiment of the stamping member, and a side view ( Figure 5b ) shows an implementation scheme of an imprinting device including such an imprinting member.

[0092] Figure 5c-5e The stamping member ( Figure 5c-5d ) and substrate ( Figure 5c-5e ) is a (cross-sectional) side view of an implementation scheme of the present invention.

[0093] Figure 5f An embodiment of an imprinting member is shown in a perspective view.

[0094] Figure 6a-6d In perspective ( Figure 6a-6b ) and the associated side view ( Figure 6c-6d ) shows an embodiment of a protruding embossing element or a protruding supporting element.

[0095] Figure 6e-6i Cutaway perspective ( Figure 6e-6f ) shows an embodiment of the support member, and a cross-sectional side view shows an embodiment of the abutment member and the support member ( Figure 6g-6h ) and embodiments of board elements or panels ( Figure 6g-6i ).

[0096] Figure 7a-7e In perspective ( Figure 7a ) shows an embodiment of a plate element or panel and shows a top view ( Figure 7b )、Bottom view( Figure 7c ) and sectional side view ( Figure 7d-7e ) shows another embodiment of a plate element or panel.

[0097] Figure 7f-7i Bottom view ( Figure 7f and 7h ) and along Figure 7f and 7h The C1-C1 section ( Figure 7g ) and C2-C2 section ( Figure 7i ) shows an embodiment of a plate element or panel.

[0098] Figure 8a-8h Bottom view ( Figure 8a , 8c -8d and 8f), top view ( Figure 8e ) and along Figure 8a , 8e and C3-C3 in 8f ( Figure 8b )、C4-C4( Figure 8g ) and C5-C5( Figure 8h ) section shows an embodiment of a plate element or panel.

[0099] Figure 9a-9b A flow chart of an embodiment of a method for manufacturing a plate element is shown.

[0100] Figure 10a-10c The preformer is shown in a side view (section) Fig.10a )、Preformed substrate( Fig.10b ) (e.g. along Fig.10d Section AA in the figure) and the imprinting device ( Fig.10c ) implementation plan and its use.

[0101] Figure 10d-10f From the bottom view ( Fig.10d ) and along Fig.10d Section BB( Fig.10e ) and CC( Fig.10f ) shows an embodiment of a plate element or panel.

[0102] Figure 11a-11b An embodiment of a board element or panel is shown in a sectional side view.

[0103] Fig.11c Embodiments of conceivable geometries of the cavities and / or the embossing elements are shown in a plan view.

[0104] Fig.11d An embodiment of the stamping member is shown in top view.

[0105] Figures 11e-11f In front view ( Fig.11e ) and side view ( Fig.11f ) shows an implementation scheme of the stamping member.

[0106] Figure 11gAn embodiment of the plate element is shown in bottom view.

[0107] Figure 12a-12c In perspective ( Fig.12a )、Side view( Figure 12b ) and front view ( Fig.12c ) shows an implementation scheme of the stamping member.

[0108] Figure 12d-12g From the bottom view ( Figure 12d-12e ) and enlarged sectional side view ( Fig.12f ) shows an embodiment of a plate element configured to be segmented into panels, and in a bottom view ( Figure 12g ) shows that it is possible to obtain, for example, Fig.12e Or an embodiment of a panel obtained by the plate element in 12f.

[0109] Figure 12h An embodiment of a plate element is shown in a cut-away side view.

[0110] Figures 13a-13d In perspective ( Figure 13a-13b ) shows a system for testing the degree of embossing of various panel samples and a side view ( Figure 13c-13d ) shows the test results. DETAILED DESCRIPTION

[0111] Next, we will refer to Figure 1a-1c , Figure 2a-2f , Figure 3a-3e , Figures 4a-4f , Figures 5a-5f , Figure 6a-6i , Figure 7a-7i , Figure 8a-8h , Figure 9a-9b , Figures 10a-10f , Figures 11a-11g and Figure 12a-12h 1 , a plurality of different embodiments of an apparatus 20 for manufacturing a plate element 1 comprising at least one cavity 2, preferably a plurality of cavities, in a back side 5 of the plate element are described with reference to the embodiments in the drawings. The apparatus 20 is capable of implementing a process for manufacturing such a plate element 1 from a substrate 3. The plate element 1 may be rectangular comprising long edge portions 1a, 1b and short edge portions 1c, 1d, but other shapes of the plate element, such as a square, are likewise conceivable.

[0112] The device 20 extends in a longitudinal direction X, a transverse direction Y and a vertical direction Z. Figure 1a-1c, 2a-2f, 3a-3e, 4a-4f, 5a-5d, 5f, 10c, 11d-11f and 12a-12c, the device 20 includes an embossing device 10, which includes at least one protruding embossing element 9, preferably a plurality of protruding embossing elements. The embossing device 10 may include an embossing member 10a and a mating member 10b. The embossing element 9 is arranged on a base 10c of the embossing member 10a and protrudes from the base 10c along a substantially normal direction / overall normal direction N of the embossing device 10, for example, the base 10c. The pressing surface 10d of the mating member 10b may be flat and / or smooth. However, in some embodiments, the pressing surface 10d may be configured to provide an embossing 3d in the front side 3c of the substrate or plate element, for example, to provide an embossing in its decorative structure 8b, see Figure 2a , 2c , 3c, 7a and 7b.

[0113] The substrate 3 in which the cavity is to be created may be disposed, for example fed, between the imprinting member 10a and the mating member 10b. During creation of the cavity 2 in the substrate, the imprinting member 10a and the mating member 10b may be configured to face the back side 3b and the front side 3c of the substrate, respectively.

[0114] In some embodiments, such as Figure 1a-1c , 2a-2b, 4a-4f, 11e-11f and 12a-12c, the embossing device 10 includes at least one roller 11, each of which is preferably rotatably arranged in the device 20. The embossing member 10a and the mating member 10b may include an embossing roller 11a and a mating roller 11b, respectively. The generally normal direction N may correspond to the radial direction R of the embossing roller 11a, preferably perpendicular to the circular base 10c. The rollers 11a and 11b can rotate around the axis AX and the axis BX, respectively, thereby defining their rotation directions.

[0115] In some embodiments, such as Figure 2c-2f , 3a-3e, 5a-5d, 5f and 11d, the embossing device 10 includes a platen assembly 12. The mating member 10b and the embossing member 10a may respectively include a mating plate 12b and an embossing platen 12a provided with a structured surface 12c. The structured surface 12c may include protrusions in the form of embossing elements 9 and an intermediate lower portion 9f such as a recessed portion disposed between these protrusions. For example, the structured surface 12c may be part of an embossing plate. The generally normal direction N may be perpendicular to a horizontal plane HP, which is preferably disposed along the base 10c.

[0116] The embossing member 10a and the mating member 10b, for example the embossing platen 12a and the mating plate 12b, are relatively movable with respect to each other along a direction V, which is preferably a vertical direction.

[0117] The platen assembly 12 may be disposed in a static press 13a such as a short cycle press (see, for example, Figure 2c ) or a multi-layer press (see for example Figure 2d-2f ) or may be arranged in a continuous press 13b such as a double belt press (see for example Figure 3a-3e )middle.

[0118] In some embodiments, the static press 13a may include at least two embossing platens 12a, and preferably at least two mating plates 12b, see e.g. Figure 2d The general schematic embodiment and Figure 2e-2f The pressing plate 12a may include an embossing element 9 on a base 10c, the embossing element 9 being arranged on a single side 12d of the pressing plate, see for example Figure 2e , or disposed on two opposite sides 12d of the pressure plate, see for example Figure 2f .like Figure 2e-2f As shown, the opposing sides 12d of the inner pressure plate 12a may be formed as part of the mating plate 12b.

[0119] For example, in Figure 2e In the embodiment, the two substrates 3 can be arranged face to face (front to back) in the press 13a. In addition, for example Figure 2f , the substrates 3 can be arranged in the press 13a face to face (front to front) or back to back (back to back).

[0120] The double belt press may include an upper endless belt unit 27a and a lower endless belt unit 27b. The embossing platen 12a may be provided as part of the belt 28b of the lower endless belt unit 27b (or the upper endless belt unit 27a), see for example Figure 3a Furthermore, the mating plate 12b may be provided as a part of the belt 28a of the upper endless belt unit 27a (or the lower endless belt unit 27b), see e.g. Figure 3a-3c and 3e.

[0121] In some embodiments, such as Figure 3c-3e As shown, a portion of the embossing platen assembly 12 may be disposed independently of the double-belt press. The embossing platen assembly 12 may include a plurality of independent embossing platens 12a, see for example Figure 3c-3d The individual embossing platens may be configured to be reusable, preferably multiple times. Figure 3c and Figure 3d The embossing platen 12a in FIG. 1 is adapted to create a cavity 2 in a single substrate 3 and to create a cavity 2 in at least two substrates 3, respectively.

[0122] In some embodiments, such as Figure 3eAs shown, the embossing member 10a comprises a flexible member 12e including the embossing element 9, which is preferably configured to be wound on reels 12f, 12g upstream and / or downstream of the double-belt press.

[0123] For example, Figure 1a-1c In any of , 2a-2f, 3a-3e, 4a-4d, 5a-5f, 6a-6d, 10c, 11d-11f and 12a-12c, the stamping member 10a, such as the stamping plate 12a or the flexible member 12e such as the stamping element 9 may include structured paper, structured sheet material such as metal sheet material or phenolic sheet material, or structured foil such as polymer-based foil. The metal may include steel.

[0124] The substrate 3 may be transferred from the inlet of the double belt press to its pressing members 29. The pressing members 29 may include an upper pressing member 29a and / or a lower pressing member 29b configured to apply pressure and preferably also heat to the substrate 3 to create the cavity 2.

[0125] Generally, in this article, the feed speed of the device 20 including the extruder can be 0.5-10 m / min, preferably 1-8 m / min, and more preferably 1.5-6.0 m / min. In addition, the feed speed of the device 20 including a continuous press such as a double-belt press can be 2-20 m / min, preferably 3-15 m / min, and more preferably 4-13 m / min. For example Figure 1a-1b The device 20 may be included in an SPC production line.

[0126] In any of the embodiments herein, for example in Figure 1a-1c In any of the embodiments of , 2a-2f, 3a-3e, 4a-4f, 5a-5d, 5f, 6a-6h, 10c, 11d-11f and 12a-12c, the protruding stamping element 9 (or the supporting element 7 defined below) can be a truncated cone or a hemispherical shape, or can be formed into a preferred rectangular parallelepiped, parallelepiped, polyhedron, pseudo-cylindrical body such as a prism, etc. Figure 6a-6d A hemispherical shaped embossed element and a pseudo-pillared / prismatic shaped embossed element are shown. For example, the shape may be determined from the base 10c.

[0127] like Figures 4a-4d, 5a-5b, 5f, 6a-6d, 11d-11f and 12a-12c, the extension lengths of the embossing element 9 along a pair of non-parallel, for example vertical, horizontal directions E1, E2 can be substantially the same. Usually here, the horizontal extension lengths E1, E2 can be determined at the bottom of the embossing element. Thus, a circumscribed cavity 2 can be created, which has a substantially identical extension length along a pair of non-parallel, for example vertical, horizontal directions D1, D2. For example, the cavity 2 can have a border that is circular or preferably a regular convex polygon, such as a triangle, rectangle / square, pentagon, hexagon, etc., see Figure 7c-7i During imprinting, the horizontally extending lengths E1 , E2 may have components along the X and Y directions.

[0128] The at least one embossing element 9 may be tapered / conical in a direction away from the base 10c, for example in a substantially normal direction N. Figure 1a-1c In any of the embodiments of , 2a-2f, 3a-3e, 4a-4f, 5a-5d, 5f, 6a-6d, 10c, 11d-11f and 12a-12c, the draft angle α between the sidewall portion 9c of the imprint element 9 and the substantially normal direction N of the imprint device 10 may exceed 0.5°, such as exceeding 1.0°, or even exceeding 3.0°. For example, α may be 0.5-70°, such as 0.5-45° or 1-30°. In some embodiments, such as Figures 4a-4f , 5a-5d, 6a, 6c, 10c, 11d-11f and 12a-12c, the side wall portion 9c may be substantially planar. Alternatively, as shown in Figure 6b and 6d As shown, the side wall portion 9c may be curved. For example, the radius RS of the stamping element may be greater than its height HS, so that α>0°, see Figure 6d Hemispherical embossed element in.

[0129] Other types of tapered embossing elements are also conceivable. In some embodiments, the at least one embossing element 9 may include a bevel, such as an outer bevel 9a and / or an inner bevel 9b, see e.g. Figure 5c The outer bevel 9a may be arranged between the side wall portion 9c and the outer wall 9d. The inner bevel 9b may be arranged in an inner region 9e adjacent to the base 10c of the stamping element 9. The bevels 9a and / or 9b may be inclined at an angle β relative to the substantially normal direction N. For example, the inclination angle β may be 10-70°, such as 25-40°, for example 45°.

[0130] The apparatus 20 may comprise a substrate forming arrangement 16, which is preferably arranged upstream of the imprinting device 10, see e.g. Figure 1a-1cThe hardened or cured substrate 3 may provide the core 8a of the plate element 1. Optionally, the substrate 3 may comprise additional layers 8, which are obtained, for example, from a coextruded substrate.

[0131] For example Figure 1a and 1b , the substrate forming arrangement 16 may include an extruder 16a (or co-extruder) and a roller assembly 16b for calendering the extrudate from the extruder. The extruder 16a may be connected to a material container 23, which is configured to receive, for example, a thermoplastic material 4 containing a thermoplastic polymer 4a and preferably also a filler 4b through a hopper.

[0132] In some embodiments, and may be, for example, Figure 1c As seen in the figure, the substrate forming arrangement 16 may include a roller mill 25, preferably a double roller mill, in communication with the material container 23, and a roller assembly 16b. The substrate forming arrangement 16 may also include a mixer 24 such as a Banbury mixer or a kneader located upstream of the roller mill 25 and preferably also includes a heater 26 for heating the thermoplastic material 4 received in the material container 23, the thermoplastic material 4 preferably comprising a thermoplastic polymer 4a and a filler 4b. The mixer 24 may include a rotatable mixing member 24a, which includes, for example, at least one rotating member. Optionally, the mixer 24 and the heater 26 may be combined. In some embodiments, the heat may be provided by friction.

[0133] Figure 1a-1c The roller assembly 16b in any of the embodiments may include at least three rollers, such as 4, 5 or 6 rollers, which are stacked one on top of the other, for example, vertically. Figure 1b In the figure, the fourth roller shown in dotted lines is optional. With the help of roller assembly 16b, the extrudate or heated material (preferably in paste form) from the roller mill 25 can be calendered into a substrate 3 in the form of a sheet, preferably a continuous sheet. The sheet can have a substantially constant thickness.

[0134] The apparatus 20 may include a substrate heating device 14. In some embodiments, such as Figure 1a-1b As shown, the substrate heating device 14 may be arranged in the substrate forming arrangement 16. For example, the extrudate from the (co)extruder may be provided at an elevated temperature TS, for example 90-225° C., such as 145-220° C. In some embodiments, and as Figure 1c and 3b As shown, the substrate heating device 14 can be a separate heating device, which is, for example, in the form of one or more warming rollers or in the form of an infrared heater. Figure 1a-1cIn any of the above, the first and second rollers 11 and the optional third roller 11 along the feed direction F may be heated / may be heated. It is obvious that the substrate 3 disclosed herein is Figure 1a-1c The substrate in any of , 2a - 2f , 3a - 3e , 5c - 5e and 10c may be provided at an elevated temperature TS by any of these alternatives.

[0135] As an alternative or in addition to the substrate heating device 14, the apparatus 20 may include a cooling unit 15 and / or 15a, which is preferably arranged downstream of the substrate heating device 14 and / or at the substrate heating device 14. The cooling unit 15 (15a) may be adapted to face the back side 3b (front side 3c) and may be configured to cool the back side 3b (front side 3c). The cooling unit 15 and / or 15a may be arranged independently and may be provided in the form of one or more warming rollers (see, for example, Figure 1a-1c ), can be provided in the form of air cooling or direct or indirect fluid cooling (see for example Figure 1a and 1c ), or may be provided in the form of a cooling zone of a double belt press (see, for example Figure 3a-3c ).

[0136] In some embodiments, the cavity 2 may be created in the substrate 3 by an isochoric pressing operation. This may be particularly advantageous when the substrate 3 is formed in the substrate forming arrangement 16, for example when provided in the form of a low viscosity paste when the cavity is created. Thus, control over the thickness of the substrate may be improved. In a first example, for example, Figure 1a-1c In any of the embodiments 2a-2b, the embossing member 10a and the mating member 10b in the form of rollers 11a, 11b may be arranged at a fixed distance from each other, for example in the vertical direction Z. In a second example, for example in Figure 2c-2f 3a - 3e , the cavity 2 may be created by applying the platen assembly 12 in an isochoric pressing operation.

[0137] In some embodiments, the cavity 2 may be created in the substrate 3 by an isostatic pressing operation, for example in a static press 13a or a continuous press 13b. This may be particularly advantageous when the substrate 3 is preformed and when its substrate portion 3a is heated separately, see e.g. Figure 2c-2f and 3a-3e.

[0138] Optionally, the substrate forming arrangement 16 may include a top layer roller arrangement 22, which includes a decorative layer roller arrangement 22a and / or a wear layer roller arrangement 22b. Figure 1a and 2b is shown in more detail in Figure 1b and 2a, but is conceivable in any embodiment herein, for example in Figure 1c , 2a -2f, 3a-3e, 4a-4f, 5a-5d, 6g-6h and 10a-10c or Figure 1c , 2a -2f, 3a-3e, 4a-4f, 5a-5d, 6g-6h and 10a-10c are relevant. Thus, the decorative structure 8b, such as the decorative layer 8c and / or the wear-resistant layer 8d, can be continuously laminated to the board element 1 after or during the formation of the board element 1. The decorative structure 8b can be applied to the board element 1 under pressure from the rollers in the top layer roller arrangement structure 22, preferably without the use of an adhesive. Optionally, the board element 1 can be heated during lamination, for example by IR heating or by means of one or more heated rollers in the top layer roller arrangement structure 22 and / or in the roller assembly 16b. In some embodiments, the decorative structure 8b can be formed by printing a print P directly, preferably digitally, on the board element 1 or the core 8a and optionally also providing a wear-resistant layer 8d on the decoration P, see for example Figure 7a In some embodiments, the backing layer 8e may be laminated to the plate element 1 after the cavity 2 is created.

[0139] In some embodiments, at least one layer 8 may be laminated to the plate element 1 in a pressing member 29 (eg, a static press), preferably under heating, see e.g. Figure 1c Layer 8 may be a decorative structure 8b and / or a backing layer 8e. Alternatively, layer 8 may provide dimensional stability to the panel. For example, layer 8 may be a mineral based layer, preferably comprising magnesium oxide and optionally magnesium chloride (e.g. MgCl2) and / or magnesium sulfate (e.g. MgSO4).

[0140] In some embodiments, such as Figure 1a-1c , 2a-2b and 6e-6h, the device 20 may also include a supporting member 18, which is suitable for supporting at least an inner portion 2f of the cavity 2 of the plate element 1 and / or for calibrating the cavity after the cavity is created. The created cavity 2 can be supported during lamination of the layer 8 to the plate element 1 and / or during cooling of at least the cavity area 2e of the plate element 1. Alternatively or additionally, the inner portion 2f can be supported during pressing of the substrate 3 between rollers. Figure 1b In this embodiment, the cavity 2 can be effectively supported during the lamination of the layer 8 and during the creation of the cavity 2.

[0141] The support member 18 may include at least one protruding support element 7, preferably a plurality of protruding support elements. The support element 7 is disposed on a base member 18c of the support member and protrudes from the base member in a generally normal direction N' of the support member 18 (e.g., the base member 18c). The support member 18 may be a support roller 18a (see Figure 1a-1b and 2a-2b) or support plate 18b (see Figure 1c and 6e -6h). The generally normal direction N' may correspond to the radial direction R' of the support roller 18a, preferably perpendicular to the circular base member 18c. Alternatively, N' may be perpendicular to a horizontal plane HP', which is preferably provided along the base member 18c. The plate element 1 may be pressed between the support member 18 and the abutment member 17, which may be an abutment roller 17a or an abutment plate 17b. Some embodiments of the support member 18 and the abutment member 17 may be the same as the embodiments of the stamping member 10a and the mating member 10b, respectively, for example in Figure 1a-1c , 2a-2f, 3a-3e, 4a-4f, 5a-5d, 6a-6d, 10c, 11e-11f and 12a-12c, to the details of which are hereby referenced.

[0142] exist Figure 1b In the embodiment shown in FIG. 1 , the third roller 11 along the feed direction F can also optionally be operated as a support member 18 , as indicated by the support element 7 in dashed lines.

[0143] The support member 18 and the abutment member 17, for example the support plate 18b and the abutment plate 17b, are relatively movable with respect to each other along a direction W which is preferably a vertical direction.

[0144] As described elsewhere herein, the form / shape of the support element 7 may be the same as that of the stamping element 9. Furthermore, for example Figure 1a The support member 18 (eg support plate 18a and / or support element 7) in any of -1d, 2a-2b and 6a-6h may comprise structured paper, structured sheet material such as metal sheet material or phenolic sheet material, or structured foil such as polymer based foil. The metal may comprise steel.

[0145] In some embodiments, for example, Figure 1b , 2b As shown in Figures 2 and 2e, at least one layer 8 can be attached (e.g., laminated) to the substrate 3 while the cavity is created and preferably supports the cavity 2. Thus, the stamping member 10a can also work as a supporting member 18. The layer 8 can be a decorative structure 8b and / or a backing layer 8e. For example, a decorative layer 8c and / or a wear layer 8d can be laminated to the substrate 3. Figure 2e An optional layer 8 is shown in dashed lines in FIG. 1 which is attached to the substrate 3 while creating the cavity 2 in the substrate. Such a layer 8 is Figure 2c-2fAny of 3a-3e and 10c is possible. In some embodiments, layer 8 may be a mineral based layer, see discussion above.

[0146] In some embodiments, the apparatus 20 may include a pre-forming device 19, see e.g. Figure 1a and 10a The preforming device 19 may be a (co)extruder 16a comprising a die 19a, which preferably has a varying shape comprising protrusions 19b and recesses 19c. The substrate 3 may be (co)extruded through an opening 19d of the die. For example, the preforming device 19 in the form of a (co)extruder 16a may include a Figure 1a-1b In the apparatus 20 of any of the Figures. In some embodiments, the preforming device 19 can be part of a pressing device.

[0147] like Fig.10b As shown most clearly in FIG. 1 , the preforming device 19 may be configured to form a substrate 3 including at least one groove 2g, preferably a plurality of grooves 2g, on the back side 3b of the substrate. The grooves may be separated by protrusions 2h. A portion of the back side 3b may be formed as a lower section of the protrusions 2h. Each groove 2g and each protrusion 2h may correspond to a protrusion 19b and a recess 19c of the extruder 16a, respectively.

[0148] Preferably, the cross section CG of the groove 2 is substantially constant along the longitudinal extension length L of the groove 2g. The cross section CG may be the area defined by the plane PR extending along the back side 3b. The opening 19d of the mold may therefore be fixed. For example, the protrusion 19b may be fixedly mounted in the mold 19a. However, in some embodiments, the cross section CG may vary along the longitudinal extension length L. For example, a variable cross section may be obtained by a mold 19a including an adjustable opening 19d. The opening 19d may include one or more movable parts 19e, preferably in the form of a movable protrusion 19b (see Fig.10a The movable part 19e is movable in the direction VM relative to the mold body 19f.

[0149] After preforming the substrate 3, the cavity 2 may be created in the back side 3b by means of an imprinting device 10, which may include, for example, Figure 1a-1b The roller 11 shown may include Fig.10c The pressure plate assembly 12 shown. Figure 10c-10f As shown, the embossing element 9 can emboss, preferably selectively emboss, the inner section 2k of the groove 2g, for example along the longitudinal extension L. Other features and examples of embossing, such as providing the substrate at an elevated temperature TS, can be similar to the embossing actions described elsewhere herein, to which reference is hereby made. Fig.10d and 10f, part of the space provided by the groove 2g can be used as an expansion area 2i for the material which is shaped, preferably moved, during embossing.

[0150] Therefore, if Figure 10d-10e as well as Fig.10b As shown, the plate element 1 may include a groove 2g and a cavity 2 having different depths DG, DC, preferably such that DC>DG. The depth DG of the groove 2g (preferably from the back side 3b to the inner section 2k of the groove) may be less than one third of the thickness T of the substrate 3, preferably one third of the maximum thickness T. For example, 0.05*T≤DG≤0.30*T. When the cross section CG varies as described above, the depth DG at the long edge portions 1a, 1b and / or the short edge portions 1c, 1d of the plate element 1 may be less than the depth in the inner portion 5a of the back side 5. In a preferred example, the depth DG may be substantially zero at the long edge portions and / or the short edge portions, so that the cross section CG is substantially rectangular, and is not zero in the inner portion 5a. Typically here (with or without the groove 2g), the depth DC of the cavity 2 (preferably from the back side 3b to the bottom wall 2d of the cavity 2) may be at least one third of the thickness T of the substrate 3, preferably the maximum thickness. For example, 0.15*T≤DC≤0.70*T, preferably 0.35*T≤DC≤0.65*T.

[0151] like Figure 1a-1c As shown, but also conceivable in any embodiment herein, the device 20 may also include a plate dividing device 21a and / or a profiling unit 21b. The plate dividing device 21a may be configured to divide the plate element 1 into at least one panel 1', for example at least two panels 1'. The profiling unit 21b may be suitable for producing locking devices 6a, 6b on at least one edge portion 1a', 1b', 1c', 1d' of the plate element 1 in the form of a panel 1' or in the form of at least one panel 1' into which the plate element has been divided. For example, the locking devices 6a and / or 6b may preferably be produced on the long edge portions 1a', 1b' and / or the short edge portions 1c', 1d' by machining.

[0152] like Figure 1c , 3a - 3e, 6i, 7a, in some embodiments, the manufactured board elements 1 or panels 1' do not comprise locking means. For example, they can be assembled in a loose / discrete configuration, preferably abutting each other.

[0153] For example Figure 1a-1c , 2a-2f, 3a-3e, 4a-4f, 5a-5d, 5f, 6e-6h, 10a, 10c, 11d-11f and 12a-12c. The device 20 is capable of implementing a method for manufacturing a plate element 1 comprising at least one cavity, preferably a plurality of cavities 2. Figure 9a and9b An embodiment of this method is shown in the flowchart in (block 30 or 40).

[0154] First, a substrate 3 comprising a thermoplastic material 4 is provided (frame 31 or 41). The substrate 3 may be preformed, and its substrate portion 3a may be heated by a substrate heating device 14 (frame 32 or 42), so that the substrate portion 3a or even the entire substrate 3 becomes placed under an elevated temperature TS. In some embodiments, the elevated temperature TS may be obtained during the formation of the substrate 3 under heating and preferably also under pressure (frame 33 or 43). For example, the substrate 3 may be at least partially formed in a (co) extruder 16a or a pressing device. In some embodiments, the substrate 3 may be preformed in a preforming device 19, which may be provided by a (co) extruder 16a. The preformed substrate 3 may include a groove 2g. In any of the above embodiments, the elevated temperature TS may exceed 40°C, preferably 40-295°C, and more preferably 100-295°C.

[0155] The substrate portion 3a, preferably the entire substrate 3, may include a thermoplastic material 4 and a filler 4b, the thermoplastic material 4 including a thermoplastic polymer 4a, such as PVC, PE, PP, TPU, PET, EVA, PA, PS, PVAc, PMMA, PVB, PC, ABS, PAM, PBT or CPVC. The filler 4b may include or may be an inorganic filler such as a mineral material, such as calcium carbonate (CaCO3), limestone such as chalk, talc, fly ash, or stone such as stone powder. When the thermoplastic material 4 includes PVC, the elevated temperature TS may be 50-210°C, preferably 60-180°C, more preferably 110-180°C. When the thermoplastic material 4 includes PP, the elevated temperature TS may be 60-220°C, preferably 70-175°C, more preferably 100-175°C. When the thermoplastic material 4 includes PET, the elevated temperature TS may be 70-295°C, preferably 110-280°C, more preferably 130-280°C.

[0156] Thereafter, a cavity 2 is created in the back side 3b of the substrate 3 by imprinting the heated substrate portion 3a by an imprinting element 9 (block 34 or 44). This can be achieved by any imprinting device 10 disclosed herein, for example Figure 1a-1c , 2a-2f, 3a-3e, 4a-4f, 5a-5d, 6a-6d, 10c, 11d-11f, and 12a-12c. In some embodiments, for example, Figure 1a-1c, 2a-2b and 3a-3e, the substrate 3 can be moved in the feeding direction F during the creation of the cavity. The substrate can be fed along the longitudinal direction X and / or the vertical direction Z. For example, the embossing device 10 includes an embossing roller 11a and a mating roller 11b, or it includes an embossing platen 12a and a mating platen 12b. Thus, a plate element 1 including a cavity 2 on its back side 5 can be obtained.

[0157] The embossing pressing cycle of the static press 13a (preferably a short cycle press) may exceed 5 seconds, for example, more than 10 seconds, preferably, when the substrate 3 is provided at an elevated temperature TS, the embossing pressing cycle may exceed 5 seconds, for example, more than 10 seconds. In a non-limiting example, the pressing cycle may be 20-50 seconds. In some embodiments, in the static press 13a, preferably in a multilayer press, the embossing pressing cycle including heating may be 10-40 minutes, for example, 15-35 minutes, for example, 20-30 minutes, followed by a cooling cycle, which may be 5-40 minutes, for example, 10-30 minutes, for example, 15-25 minutes. The embossing pressing cycle of a continuous press (e.g., a double belt press) may be 20-400 seconds, for example, 25-220 seconds, for example, 30-180 seconds.

[0158] When a preformed substrate 3 having a groove 2g is provided, the heated substrate portion 3a may include an inner section 2k of the groove 2g, and the cavity 2 may be created by stamping the inner section 2k by the stamping element 9 (block 34).

[0159] The act of embossing may include applying a pressure of 0.4-5.0 MPa, such as 0.5-4.0 MPa or 0.6-3.0 MPa to the substrate portion 3a. For example, the applied pressure may be 0.7-2.5 MPa, such as 1.0-2.0 MPa. For the static press or continuous press disclosed herein, any of the above pressures is conceivable.

[0160] In some embodiments, the method may include forming at least one chamfer 2a, 2b in one or more cavities 2. Chamfers such as outer chamfer 2a and / or inner chamfer 2b may be formed by a bevel of the stamping element 9 such as inner chamfer 9b and / or outer chamfer 9a. Chamfers 2a, 2b may be arranged along a longitudinal extension length LE and / or a transverse extension length TE of the cavity 2, for example along the entire circumference / circumference of the cavity. Each chamfer 2a, 2b may be arranged between a cavity wall 2c and a back side 3b, 5, or between a cavity wall 2c and a bottom wall 2d of the cavity 2. Chamfers 2a, 2b may be inclined by a chamfer angle γ relative to a normal direction M of the substrate 3 or the plate element 1, see for example Figure 5c and 5e The chamfer angle γ may be 10-70°, such as 25-40°, for example 45°. The bevels 9a, 9b and / or chamfers 2a, 2b may be substantially planar (see Figure 5c) or rounded / rounded (see Figure 5e and Figure 5c The substantially planar bevel and / or substantially planar chamfer may extend for 0.07-2 mm, for example 0.1-1 mm. For a rounded bevel or rounded chamfer, the radius RB may be 0.05-2.5 mm, for example 0.1-1.2 mm.

[0161] More generally, the method may comprise creating a tapered / tapered one or more cavities 2 by means of a tapered / tapered stamping element 9, see e.g. Figure 5d The cavity 2 may taper / narrow along the longitudinal extension LE and / or the transverse extension TE. The cavity wall 2c may be inclined at a wall angle δ relative to the normal direction M, see e.g. Figure 5d The wall angle δ may exceed 0.5°, such as exceeding 1.0°, or even exceeding 3.0°. Alternatively or additionally, the wall angle δ may be less than 80°, such as less than 70°, or even less than 50°. For example, the wall angle δ may be 0.5-70°, such as 0.5-45° or 1-30°. As an alternative or in addition to the conical cavity wall 2c, the conical cavity 2 may include the above-mentioned chamfers 2a, 2b.

[0162] In general here, the form / shape of the cavity 2 may correspond to the form / shape of the embossing element 9. For example, the draft angle α and the wall angle δ may correspond to each other and / or the bevel angle β and the chamfer angle γ may correspond to each other.

[0163] In some embodiments, such as Figure 3b , 5f As shown in FIGS. 11d-11f and 12a-12c, the stamping member 10a may include a first group 9g and a second group 9h (or 9h') of stamping elements 9, and the first group and the second group are separated from each other by a blank portion 10e (or 10f) along the separation direction S1 (or S2). The distance L2 (or L2') between the stamping elements between the first group and the second group along the separation direction S1 (or S2) is greater than the distance L1 (or L1') between the stamping elements in each of the first group 9g and the second group 9h (or 9h'). For example, Figure 3b , 5f, 11d and 12a-12c, the stamping member 10a may sometimes include a plurality of such second groups 9h, 9h' along the separation directions S1 and / or S2. Generally in this document, the ratio of L2 / L1 may be at least 3, preferably at least 5, for example at least 10. For example, 3≤L2 / L1≤10. In addition, the ratio of L2 / L1 may be at least 2, preferably at least 5, for example at least 10. For example, 2≤L2' / L1'≤10. In a non-limiting example, L1 (or L1') may be 1-10mm, preferably 1-5mm, more preferably 1.5-4mm, and L2 (or L2') may be 5-100mm, preferably 10-75mm, more preferably 12-50mm. The separation directions S1 and S2 may be parallel to and perpendicular to the operating direction OD of the stamping member 10a, such as the direction of rotation, respectively. It is clear to the skilled person that other features of the stamping device 10 may be similar to those described elsewhere herein, such as regarding Figures 4a-4d , those described in 5a-5f and 6a-6d.

[0164] In the first example, the stamping member 10a includes a first group 9g and a second group 9h of stamping elements 9 separated by a blank portion 10e. In the second example, the stamping member 10a includes a first group 9g and a second group 9h' of stamping elements 9 separated by a blank portion 10f. In the third example, the stamping member 10a includes a first group 9g and a second group 9h of stamping elements 9 separated by a blank portion 10e, and a first group 9g and a second group 9h' of stamping elements 9 separated by a blank portion 10f. It should be emphasized that in any of the above examples, there may be additional second groups 9h", 9h"', 9h"" defined in a similar manner to the adjacent "first groups 9h, 9h', 9h", for example, Figure 12a-12c Note that when there is only one blank portion 10e on the periodic stamping member 10a (e.g. Figure 11d-11f The endless belt unit 27b or the embossing roller 11a), the first group 9g and the second group 9h can be the same.

[0165] exist Figure 4e-4f In the embodiment, two or more groups 9g, 9h of elongated stamping elements 9 (described further below) are separated by a blank portion 10e along the operating direction OD of the stamping member 10a.

[0166] Preferably, the embossing element 9 described here is separated from the edge section 10g of the embossing member 10a by a space 10f', for example in a direction perpendicular to the operating direction OD. Thus, as described elsewhere herein, the cavity 2 can be arranged in the interior 5a of the back face 5. During operation of the embossing device 10, the edge section 10g can extend transversely to and optionally along the feed direction F, for example along the separation direction S1 and / or S2.

[0167] Likewise, for example Figure 6f As shown, any support member 18 herein may comprise a first series 7a and a second series 7b (or 7b') of support elements 7, which are separated from each other by empty portions 18d (or 18e).

[0168] Optionally, the cavity area 2e (preferably the back side 3b, 5) of the plate element 1 or substrate 3 can be cooled (block 36 or 45) by a cooling unit 15 adapted to face the back side 3b during and / or after the creation of the cavity 2. The cavity area 2e can be cooled from the elevated temperature TS to a cooling temperature Tc below the elevated temperature.

[0169] In some embodiments, the cavity region 2e may be cooled to a cooling temperature Tc such that 0.8≤Tc / Tg≤1.9. When the thermoplastic material 4 includes PVC, the range may be 0.8≤Tc / Tg≤1.4. When the thermoplastic material 4 includes PET, the range may be 1.0≤Tc / Tg≤1.7. When the thermoplastic material 4 includes PP, the range may be 1.0≤Tc / Tg≤1.9.

[0170] In a non-limiting example, for a semi-crystalline polymer such as PET, the cavity region 2e can be cooled (i.e., lowered) by at least 20°C, preferably 20-120°C, from the elevated temperature, and for an amorphous polymer such as PVC, the cavity region 2e can be cooled by at least 30°C, preferably 30-90°C, from the elevated temperature.

[0171] In some embodiments, the cavity region 2e may be cooled from the elevated temperature TS by at least 10°C, preferably 10-100°C, to below the Tm of the thermoplastic material 4 (eg, comprising PP, PE, TPU or EVA).

[0172] In some embodiments, the interior portion 2f of the created cavity 2 may be supported during cooling (blocks 35, 36, and 45).

[0173] As an alternative or in addition to cooling the cavity area 2e, the front side 3c may be cooled (block 36 or 45) by a cooling unit 15a adapted to face the front side 3c during and / or after creation of the cavity 2. The cooling may provide a well-defined and uniform front side.

[0174] Optionally, layer 8 may be attached, such as laminated or adhered, to plate element 1 (blocks 37 or 44). Figure 1b , 2bAs shown in Figures 2 and 2e, while creating the cavity 2, a layer 8 can be attached to the substrate 3 (frame 44). The layer 8 can be a decorative structure 8b and / or a backing layer 8e. Preferably, during the attachment of the layer 8 to the plate element 1 or substrate (frames 35 and 37 or frame 44), at least the inner portion 2f of the created cavity 2 is supported, see Figure 2e. Figure 1a-1c , 2a-2b, 2e and 6g-6h.

[0175] As an alternative or in addition to supporting the inner part 2f during the attachment layer 8, the base plate part 3a or the plate element 1 can be cooled after the creation of the cavity 2 and before the attachment layer 8, see e.g. Figure 1a , 1c and 2a.

[0176] The plate element 1 here can be provided in the form of a panel 1', or can be divided into at least one panel 1', such as at least two panels, wherein each panel is a building panel, a floor panel, a wall panel, a ceiling panel or a furniture component. In fact, an embodiment of the method disclosed herein (see, for example, frame 30 or 40) may also include dividing the plate element 1 into at least one panel, such as at least two panels 1', by a plate dividing device 21a. For example, the plate element 1 can be divided into a plate component 1' by a first dividing unit 21a', and the plate component 1' can be further divided into at least two panels 1' by a second dividing unit 21a", wherein the panels are preferably divided into a substantially final form. Preferably, the plate element 1 or the plate component 1' is divided at a temperature higher than the initial temperature and / or the ambient temperature of the substrate 3. Any division disclosed herein can be achieved by machining, such as by using a tool, a rotary cutting tool, etc.

[0177] In some embodiments, the plate element 1 is divided into plate members 1″ at dividing portions DP in the form of partitions 5b. Figure 11g and 12d -12f. Alternatively, the plate member 1" may be divided into a plurality of panels 1' at a partition portion DP' in the form of a partition portion 5b'.

[0178] Indeed, in some embodiments, and as Figure 8d , 11gAs shown in Figs. 12d-12g, cavities 2 separated by partitions 5b and / or 5b' may be created in a board element 1 or panel 1'. The first group 2m and the second group 2n (or 2n') of cavities 2 may be separated from each other by partitions 5b (or 5b') along one or two panel or board directions PD (or PD'), preferably perpendicular panel or board directions PD (or PD'), the partitions 5b (or 5b') preferably being formed as continuous sections along the panel or board directions PD and / or PD' between opposite edge portions 1a, 1b and / or 1c, 1d (or 1a', 1b' and / or 1c', 1d' in the case of panel 1'). Preferably, the panel or board directions PD and PD' are the longitudinal direction LD and the transverse direction TD of the board element or panel (or vice versa), respectively.

[0179] like Figure 12d-12g As shown, the distance K2 (or K2') between the cavities 2 along the panel direction or the board direction PD (or PD') between the first group 2m and the second group 2n (or 2n') can therefore be greater than the distance K1 (or K1') between the cavities within each of the first and second groups 2m (or 2n). Furthermore, it is emphasized that the plate element 1, the plate member 1″ or the panel 1′ may sometimes comprise a plurality of such second groups 2n, 2n′ along the panel direction or the plate direction PD and / or PD′. Typically in this document, the ratio K2 / K1 may be at least 3, preferably at least 5, for example at least 10. For example, 3≤K2 / K1≤10. Furthermore, the ratio K2' / K1' may be at least 2, preferably at least 5, for example at least 10. For example, 2≤K2' / K1'≤10. In a non-limiting example, K1 (or K1') may be 1-10 mm, preferably 1-5 mm, more preferably 1.5-4 mm, and K2 (or K2') may be 5-100 mm, preferably 10-75 mm, more preferably 12-50 mm.

[0180] Optionally, one or more edge portions 1a-1d of the substrate 3 may be trimmed after the creation of the cavity 2, for example by cutting with a rotary cutting device or with one or more knives, or by punching. Fig.12e As shown in FIG. 1 , after trimming along the trimming portion TP (see the outermost dotted line), a Fig.12d Edge portions 1a - 1d are shown. Preferably, edge portions 1a - 1d are trimmed when substrate 3 is exposed to elevated temperature TS, see discussion above.

[0181] Alternatively or additionally, the method may further comprise producing locking means 6a, 6b at at least one edge portion 1a', 1b', 1c', 1d' by means of a profiling unit 21b. Preferably, the locking means 6a, 6b are produced on two opposite edge portions of the panel 1'.

[0182] The partition portion 5b (or 5b') can be used as a reinforcing plate area in which no cavity 2 is arranged. Alternatively, it can be used as a partition portion DP (or DP') of the plate element 1, see Figure 11g and 12d -12f. After the plate elements have been divided, locking means 6a may be produced at the edge portions 1a', 1b' of the panel 1' by removing plate material 1e, for example by machining. Thus, a panel 1' with edge portions 1a', 1b' may be obtained, for example Figure 7b-7d , panels in any one of 7f-7i, 8a, 8c-8f, 8h, 11a or 12g-12h. Figure 12d-12f The long edge portions 1a', 1b' are shown, but it is emphasized that a similar splitting process is also conceivable for splitting the plate element 1 and producing the locking means 6b at the short edge portions 1c', 1d' of the panel 1', see Figure 7b-7c , 7e-7f, 7h, 8a-8g, 11b or 12g. The strip 6c' may extend in horizontal direction beyond the upper part of the plate element 1 and a locking element 6d' for horizontal locking may be provided on the strip.

[0183] In some embodiments, the apparatus 20 may further comprise an annealing unit / heat treatment unit 21c, which is preferably arranged after at least a portion of the plate segmentation device 21a and before the profiling unit 21b, see e.g. Figure 1a-1c In a non-limiting example, Figure 1a As can be seen most clearly in FIG, the annealing unit 21c can be arranged after the first segmentation unit 21a' and before the second segmentation unit 21a". When the cavity area 2e and / or the front side 3c are cooled by the cooling unit 15 and / or 15a (frame 36 or 45), annealing is preferably performed after cooling.

[0184] Annealing (frame 38 or 46) may include heating the plate element 1 or plate member 1″ to an annealing temperature of 80-170°C, for example 120-145°C, for example 130-140°C, preferably when the thermoplastic material 4 includes PVC and filler 4b such as an inorganic filler. For example, the annealing unit 21c may include at least one of a heating furnace, a hot air heater and a hot bath containing a fluid (e.g., water).

[0185] Figure 6i , 7a-7i, 8a-8h, 10d-10f, 11a-11b, 11g and 12d-12h show further embodiments of a board element 1 such as a panel 1' obtainable by the method described herein. The board element 1 or the panel 1' comprises at least one layer 8 comprising a thermoplastic material 4, and comprises a cavity 2 in the back side 5. Typically, the board element or panel may be multilayered, for example obtained by coextrusion or by attaching (e.g. laminating) one or more layers 8 to a core 8a. For example, the board element or panel may comprise a core 8a and a decorative structure 8b, such as a decorative layer 8c and / or a wear-resistant layer 8d. The decorative layer and / or the wear-resistant layer may be provided as a thermoplastic-based foil or film, for example comprising PVC. The thickness of the decorative layer and the wear-resistant layer may be 0.01-0.10 mm and 0.05-2.0 mm, respectively. In some embodiments, the decorative structure 8b may comprise embossing 3d, see Figure 7a-7b Optionally, the panel may further comprise a backing layer 8e and / or a covering layer 8f, such as a foam layer; see also Figure 12h Layer 8 may also be a mineral based layer, see discussion above.

[0186] Any, some or each layer 8, 8a, 8b, 8c, 8d, 8e, 8f may comprise a thermoplastic material 4 and a filler 4b, the thermoplastic material 4 comprising a thermoplastic polymer 4a such as PVC. Other materials such as PE, PP, TPU, PET, EVA, PA, PS, PVAc, PMMA, PVB, PC, ABS, PAM, PBT or CPVC are equally conceivable. The filler 4b may comprise or may be an inorganic filler, such as a mineral material. Typically in this article, the thermoplastic material 4 may also comprise an additive 4c, such as at least one of a stabilizer, a foaming agent or a blowing agent, a plasticizer, a colorant, a pigment, a lubricant, an impact modifier, a processing aid, etc. For example, a layer 8 of a panel 1, such as a core 8a, which may be obtained by an embodiment of the method described herein, may comprise 10-40wt% of PVC, 50-90wt% of an inorganic filler such as chalk, and 0-20wt% such as 5-20wt% of an additive.

[0187] Additives 4c in the thermoplastic material 4, such as plasticizers and / or lubricants, can help increase the flow of the material, for example in the (co)extruder 16a, so that a more controlled imprint can be obtained. Plasticizers such as dioctyl terephthalate (DOTP) can soften the thermoplastic material 4. The lubricant can be an internal lubricant such as a fatty alcohol or a fatty glyceride, and / or an external lubricant such as a wax, for example PE wax or paraffin. For example, the content of the plasticizer can be 1-25wt%, preferably 3-20wt%, and / or the content of the lubricant can be 0.2-5wt%, preferably 1-2wt%. In addition, additives 4c such as processing aids can be included to improve the melting of the thermoplastic material 4 during the formation of the substrate 3 and / or to reduce the formation of cracks during imprinting. For example, the content of processing aids such as acrylic processing aids can be 0.5-5wt%, preferably 1-3wt%.

[0188] In some embodiments, the thermoplastic polymer 4a may include a PVC-PVAc copolymer and optionally PVC. Thus, the thermoplastic material 4 may become softer and easier to process, whereby embossing may become simpler. For example, the content of the PVC / PVAc copolymer may be 5-100wt%, preferably 8-25wt%.

[0189] In any embodiment of the substrate 3 or the board element 1 or the panel 1 ' herein, for example Figure 1a-1c , 2a-2f, 3a-3e, 5c-5e, 6g-6i, 7a-7i, 8a-8h, 10b-10f, 11a-11b, 11g and 12d-12h, in any of the embodiments, the surface of the inner part 2f of the cavity 2, such as the surface of the cavity wall 2c and / or the bottom wall 2d, can be closed. When groove 2g exists, the surface of the inner section 2k of groove 2g can be closed. This closed surface can be obtained and / or maintained by the embodiment of the method described herein, thus by stamping, preferably by the shaping of material and / or by making the material shift to create cavity and / or groove. When forming substrate 3 under heat and preferably also under pressure and / or by (co) extrusion, the closed surface can be formed. For example, the closed surface can be included in the outer shell layer or the surface layer obtained when forming substrate 3. The closed surface can be maintained when stamping the back side 3b. For example, the closed surface may extend continuously from the back side 3b, 5 of the substrate 3 or plate element 1, for example, thereby having substantially no interruption in the surface integrity. Preferably, the closed surface is non-porous. Thus, such a closed surface may be in sharp contrast to a processed or machined surface (open surface) obtained, for example, by a rotary cutting device (e.g., as described in WO 2020 / 180237).

[0190] In some embodiments, and as shown, for example in Figure 7a-7i, 8c-8h, 10d-10e, 11a-11b, 11g and 12d-12h, the cavities 2 may be arranged in the interior 5a of the back side 5, whereby they are spaced apart from a pair of opposing long edge portions 1a, 1b and / or a pair of opposing short edge portions 1c, 1d (or 1a', 1b' and / or 1c', 1d' in the case of a panel 1'). This may be achieved in the method by a space / space 10f'. Alternatively, they are spaced apart from all edge portions 1a', 1b', 1c', 1d' of the panel, such as Figure 7c-7e , 8c-8d, 11a-11b, 11g and 12d-12h. The cavity 2 may be disposed inside the locking device 6a and / or 6b, as shown in Figure 7b-7e For example, the cavity 2 may be disposed inside the horizontal innermost portions 6e, 6f of the locking devices 6a and / or 6b, see Figure 7d-7e .

[0191] In some embodiments, such as Figure 7a-7i As shown in Figures 8a-8b, 11a-11b, 11g and 12d-12h, the longitudinal extension length LE and the transverse extension length TE of the cavity 2 may be substantially equal.

[0192] In some embodiments, the embossed cavity 2 may be elongated, whereby the longitudinal extension LE exceeds the transverse extension TE. For example, the elongated cavity 2 may be created by an elongated embossing element 9, which is disposed, for example, on an embossing roller 11a or an embossing platen 12a. Figure 4e-4f As shown, the elongated stamping element 9 may be arranged along a portion of the base 10c, for example, along its circumference. Figure 8c-8d As shown, the longitudinal extension direction / length of the cavity 2 may be parallel to the long edge portions 1a, 1b (or 1a', 1b') of the plate element 1 (or panel 1'). Such an elongated cavity ("groove 10") is shown in e.g. Figure 13b-13d , 14a-14g and 16e, and described in, for example, pages 49, lines 25 to 50, lines 4 and 18-20, and page 51, lines 15 to 53, line 19 of WO 2020 / 180237, which are expressly incorporated herein by reference. In a second example, the elongated cavity 2 may be parallel to the short edge portions 1c, 1d (or 1c', 1d') of the plate element 1 (or panel 1'), see, for example Figure 8e-8h .

[0193] In any embodiment herein, the elongated cavity 2 may be continuous, for example Figure 8c and 8fAs shown, or it is discontinuous, preferably separated by separation parts 5b, 5b', for example Figure 8d shown.

[0194] Often in this article, e.g. Figure 8a-8h In the embodiment, the elongated cavity 2 and / or the elongated embossing element 9 (see for example Figure 4e-4f ) can be 1<LE / TE≤150, for example 6≤LE / TE≤120, preferably 10≤LE / TE≤100 (also LE' / TE'). For cavities 2 parallel to the long edge portions 1a, 1b (or 1a', 1b') or the short edge portions 1c, 1d (or 1c', 1d'), any of these ratios is conceivable. For the embossing element, TE' and LE' can be measured along the base 10c, for example along the circumference (see Figure 4f ).

[0195] For example, Figure 6h , 7a The cavity 2 in any of -7i, 8a-8h, 10d-10f, 11a-11b, 11g and 12d-12h may comprise at least one chamfer 2a, 2b, as has been described in detail elsewhere herein. Figure 5c and 5e Examples of such chamfers provided along the longitudinal extension LE and / or the transverse extension TE are shown. For example, the chamfer in the elongated cavity 2 may be provided along its longitudinal extension LE and, optionally, along its transverse extension TE. When LE and TE are substantially equal, the chamfer may be provided along the entire circumference / periphery 2j of the cavity 2, see e.g. Figure 7c and comparison Figure 6a-6d .

[0196] As an alternative or in addition to chamfers 2a, 2b, Figure 6i , 7a The cavity 2 in any one of -7i, 8a-8h, 10d-10f, 11a-11b, 11g and 12d-12h may be gradually tapered / conical by including an inclined cavity wall 2c along the longitudinal extension LE and / or the transverse extension TE, as described in detail elsewhere herein. Examples of such tapered cavities are Figure 5d , 7d - is most clearly shown in 7e, 7g, 7i, 8b, 8g, 8h and 12h.

[0197] The base plate 3 or the plate element 1 , such as the panel 1 ′, can have a thickness T of 2-10 mm, which is preferably the maximum thickness T.

[0198] In some embodiments, the cavity 2 may intersect / overlap at least a portion of the locking means 6a and / or 6b. For example, the cavity 2 may open outwardly horizontally, for example in the transverse direction TD and / or the longitudinal direction LD of the plate element 1. By these intersections, components of the locking means may be damaged along the edge portions. However, for many applications, the resulting locking strength may be sufficient, especially when the cavity 2 intersects the locking means 6a. In practice, the long edge portions 1a, 1b have a greater extension and therefore may provide a larger locking portion overall.

[0199] It should be emphasized that the intersecting cavity 2 can be created in any way, for example by embossing or by removing material, for example by a rotary machining device or by engraving or scraping, for example, as described in WO 2020 / 180237, page 58, line 26 to page 63, line 6 and Figures 1, 17a-17e and 18a-18b, which parts are explicitly introduced here as reference.

[0200] The cavity 2 may be formed in one long edge portion 1a' (see Figure 7f-7g and Figure 8a-8b , 8e-8h, including Figure 8h 5) or in the two long edge portions 1a', 1b' (see Figure 7h-7i and Figure 8e-8h ,include Figure 8f and 8h The horizontal dotted line (in the vicinity of the mid-length edge portion 1b') at least partially intersects the locking device 6a.

[0201] In some embodiments, the locking device 6b may be free of the cavity 2, see e.g. Figure 7c-7i and 8c-8h. For example, Figure 7f-7g and Figure 7h-7i As shown respectively, the cavity 2 may intersect the locking device 6a horizontally on one long edge portion 1a' or both long edge portions 1a', 1b'. One long edge portion 1a' may include a strip 6c extending horizontally beyond the upper part of the panel 1', and a locking element 6d for horizontal locking may be provided on the strip, see Figure 7d .

[0202] In some embodiments, the cavity 2 may at least partially intersect the locking device 6b, see e.g. Figure 8a-8b The cavity 2 may be formed at the two short edge portions 1c', 1d' (see Figure 8a-8b ) at least partially intersect the locking device 6b and / or extend below the locking device 6b, but it is also conceivable that they only at least partially intersect the locking device 6b on a short edge portion 1c' or 1d'.

[0203] In some embodiments, the depth DC of the cavity 2 is smaller at the long edge portions 1a', 1b' and / or the short edge portions 1c', 1d' than in the interior 5a. The depth DC of the cavity 2 at the locking means 6a and / or 6b, for example at the strip 6c, may be smaller than the depth DC in the interior 5a, see Figure 7g , 7i For example, the depth may gradually decrease toward the edge portions 1a', 1b' and / or 1c', 1d', see Figure 11a-11b .

[0204] like Figure 12h As shown, in some embodiments, the panel 1 may include a backing layer 8e, preferably, the backing layer 8e is attached to (e.g., laminated to) the core 8a or another layer 8 of the panel. The backing layer 8e may be a balancing layer. The backing layer 8e may be thinner and / or more flexible than the core or layer to which it is attached. The thickness TB1, TB2 of the backing layer is preferably variable. The thickness TB1 at the position of the cavity 2 may be different from, preferably less than, the thickness TB2 at the position near the cavity 2 and / or between the cavities 2. For example, the variable thickness may be caused by the embossing of the cavity, for example, by stretching and / or compressing the material in the backing layer. In a non-limiting example, TB1<0.8*TB2, for example TB1<0.6*TB2. However, it is also conceivable that the backing layer has a substantially constant thickness (including TB2=TB1).

[0205] The backing layer 8e may be continuous at least at the location of the cavity 2. Preferably, the entire backing layer 8e is continuous, such as Figure 12h shown.

[0206] Example

[0207] The dependence of the embossing degree on the temperature variation was tested on a set of sample pairs Q1-Q9 (and Q1'-Q9') consisting of identical SPC panels (and identical LVT panels), each in the form of a homogeneous core with a density of 2083 kg / m 3 , flexural modulus is 8240N / mm 2 (density is 1948kg / m 3 , flexural modulus is 1599N / mm 2 ). Flexural modulus was tested according to ISO 178:2010 / A1:2013. Each pair contained two identical samples. The size of each sample was 100 mm×100 mm and the thickness was 5 mm.

[0208] Heat each pair of samples to the uniform temperature specified in Tables 1 and 2. Fig.13aThe heated samples in pairs Q1-Q7 and Q1'-Q7' were both pressed by a pressing device including a cylindrical pressing element with a diameter of 8 mm for about 10 seconds, while the heated samples in pairs Q8-Q9 and Q8'-Q9' were pressed by a pressing device including a conical pressing element, see Fig.13b , whereby cylindrical and conical cavities are obtained, respectively, see Figure 13c-13d The conical stamping element comprises an inner cylindrical portion with diameter = 8 mm, a frustoconical end portion with height H = 2 and an outer disc-shaped area with diameter = 5 mm. Both stamping elements consist of solid tool steel.

[0209] See also Figure 13a-13b The closed surfaces of the back sides of the two samples in each pair are embossed identically at the same temperature by applying a constant force of f0 = 98 N on the embossing element and against the corresponding sample. The average degree of embossing w0 of the corresponding sample pair is then determined according to the formula w0 = (w1 + w2) / 2, where w1, w2 are the maximum embossing depths measured from the back side of the corresponding sample in each pair, see Figure 13c-13d and summarized in Tables 1 and 2. Calipers were used to determine depth.

[0210] Table 1 - Average embossing depth of heated samples

[0211] Temperature(℃) sample Depth(mm) sample Depth(mm) 40 Q1 0 Q1’ 0.04 60 Q2 0 Q2’ 0.09 100 Q3 0.11 Q3’ 0.22 140 Q4 0.57 Q4’ 1.26 160 Q5 0.78 Q5’ 1.72 180 Q6 1.74 Q7’ 3.10 220 Q7 3.30 Q7’ 3.30

[0212] It can be seen from Tables 1 and 2 that for a given imprinting element, the imprint depth w0 increases as the sample temperature increases. It can also be concluded that a greater degree of imprinting begins at temperatures at or above 100°C.

[0213] Table 2 - Average embossing depth of heated samples

[0214] Temperature(℃) sample Depth(mm) sample Depth(mm) 140 Q8 0.83 Q8’ 1.33 160 Q9 1.03 Q9’ 2.30

[0215] By comparing Table 1 and Table 2, it can be seen that for a fixed temperature, the embossing depth w0 increases when a conical embossing element is used. It is also found that a smoother surface structure is obtained on the back side of the embossing. For example, a closed surface on the back side is maintained to a higher degree. Finally, it is found that it is easier to remove the embossing element from the samples in pairs Q8, Q9, Q8' and Q9'.

[0216] Aspects of the present disclosure have been mainly described above with reference to some embodiments. However, as will be readily appreciated by a person skilled in the art, other embodiments than those disclosed above are equally possible within the scope of the present disclosure. For example, it is emphasized that the blank portions 10e and / or 10f may, in some embodiments, optionally comprise embossed elements 10h, which are preferably smaller than the embossed element 9, for example, by 50%, preferably by 70%, more preferably by 90%, for example, in terms of height HS and / or extension, preferably in terms of extension in horizontal directions E1, E2, see Figure 6a-6d Such an embossed element 10h will form an embossed structure 2p in the separating portion 5b and / or 5b', which is preferably smaller than the cavity 9, for example 50%, preferably 70%, more preferably 90% smaller, e.g. in height DC and / or extension, preferably in horizontal direction D1, D2 or in extension length TE, LE, see Figure 8h .

[0217] Implementation

[0218] Other aspects of the present disclosure are provided below. The embodiments, examples, etc. of these aspects are largely similar to the embodiments, examples, etc. described above, and reference is made to the detailed description above.

[0219] Item 1. A method for manufacturing a plate element (1) comprising at least one cavity (2), preferably a plurality of cavities, on its back side (5), wherein the method comprises:

[0220] providing a substrate (3) comprising a thermoplastic material (4), wherein the substrate comprises a substrate portion (3a); and

[0221] The plate element (1) is obtained by creating the at least one cavity (2) on the back side (3b) of the substrate (3) by embossing the substrate portion (3a) via an embossing device (10) comprising at least one protruding embossing element (9).

[0222] Item 2. The method according to Item 1, wherein the embossing device (10) comprises at least one roller (11).

[0223] Item 3. The method according to Item 1, wherein the embossing device (10) comprises an embossing platen (12a), the embossing platen being provided with a structured surface (12c), the structured surface comprising the at least one protruding embossing element (9).

[0224] Item 4. A method according to any one of the preceding items, wherein a first group (9g) and a second group (9h; 9h') of the embossing elements (9) are separated from each other along a separation direction (S1; S2) by a blank portion (10e; 10f), and an inter-embossing element distance (L2; L2') between the first group and the second group along the separation direction (S1; S2) is greater than an inter-embossing element distance (L1; L1') within each of the first group and the second group.

[0225] Item 5. The method according to any of the preceding items, wherein, when creating the at least one cavity (2), the substrate portion (3a) is placed at an elevated temperature (TS).

[0226] Item 6. The method according to Item 5, wherein the elevated temperature (TS) is obtained by heating the substrate portion (3a).

[0227] Item 7. The method according to Item 5, wherein the elevated temperature (TS) is obtained during forming the substrate (3) under heating and preferably also under pressure.

[0228] Item 8. The method according to any one of the preceding items 5-7, wherein the elevated temperature (TS) exceeds 40°C, preferably 40-295°C, and more preferably 100-295°C.

[0229] Item 9. The method according to any one of the preceding items, wherein the imprinting comprises applying a pressure of 0.4-5.0 MPa to the substrate portion (3a).

[0230] Item 10. The method according to any one of the preceding items, further comprising forming the substrate (3) under heating and preferably also under pressure and / or by (co)extrusion.

[0231] Item 11. The method according to any of the preceding items, further comprising cooling at least the cavity region (2e) of the substrate (3) or of the plate element (1) during and / or after creating the at least one cavity (2).

[0232] 12. A method according to item 11, wherein the cavity region (2e) is cooled to a cooling temperature (Tc), the cooling temperature being in the range of 0.8 to 1.9 times the glass transition temperature (Tg) of the thermoplastic material (4), wherein the cooling temperature (Tc) and the glass transition temperature (Tg) are expressed in Kelvin.

[0233] Item 13. The method according to any one of the preceding items, further comprising attaching a layer (8) to the plate element (1).

[0234] Item 14. The method according to any of the preceding items also includes supporting at least an inner portion (2f) of at least one cavity (2) created during lamination of the layer (8) onto the plate element (1) and / or during cooling of at least the cavity area (2e) of the plate element (1).

[0235] Item 15. The method according to Item 13 or 14, wherein the layer (8) is a decorative structure (8b) and / or a backing layer (8e).

[0236] Item 16. The method according to any one of the preceding items also includes forming at least one chamfer (2a, 2b) in the at least one cavity (2), each chamfer being located between the cavity wall (2c) and the back side (3b; 5), or between the cavity wall (2c) and the bottom wall (2d) of the cavity (2).

[0237] Item 17. The method according to any of the preceding items, further comprising creating at least one conical cavity (2) by means of at least one conical embossing element (9).

[0238] Item 18. A method according to any of the preceding items, wherein a draft angle (α) between a side wall portion (9c) of the at least one embossing element (9) and a substantially normal direction (N) of the embossing device (10) exceeds 0.5°.

[0239] Item 19. The method according to any of the preceding items also includes moving the substrate (3) in a feed direction (F), preferably moving the substrate (3) in the feed direction (F) during the creation of the at least one cavity.

[0240] Item 20. The method according to any one of the preceding items, further comprising pre-forming the substrate (3) prior to creating the at least one cavity (2).

[0241] Item 21. A method according to any of the preceding items, wherein the panel element (1) is provided in the form of a panel (1'), or the panel element (1) can be divided into at least one panel such as at least two panels, each of which is a building panel, a floor panel, a wall panel, a ceiling panel or a furniture component.

[0242] Item 22. The method according to any one of the preceding items, further comprising annealing the plate element (1) after creating the at least one cavity (2).

[0243] Item 23. A board element (1), such as a panel (1'), obtainable by a method according to any one of the preceding items 1-22.

[0244] Item 24. A panel (1') comprising at least one layer (8) comprising a thermoplastic material (4), wherein the panel comprises at least one cavity (2), preferably a plurality of cavities, on a back side (5) of the panel.

[0245] Item 25. A panel according to Item 24, wherein the at least one cavity (2) comprises at least one chamfer (2a, 2b), each chamfer being located between the cavity wall (2c) and the back side (5), or between the cavity wall (2c) and the bottom wall (2d) of the cavity (2).

[0246] Item 26. The panel according to item 24 or 25, wherein the at least one cavity (2) is conical.

[0247] Item 27. The panel according to Item 26, wherein the cavity wall (2c) is inclined at a wall angle (δ) exceeding 0.5° relative to the normal direction (M) of the substrate (3).

[0248] Item 28. A panel according to any one of the preceding items 24-27, wherein the at least one cavity (2) is arranged in the interior (5a) of the back side (5), so that the at least one cavity is spaced apart from a pair of opposite edge portions (1a, 1b; 1c, 1d) of the panel, such as the opposite short edge portions of the panel, and optionally, the at least one cavity is spaced apart from all edge portions of the panel.

[0249] Item 29. A panel according to any one of the preceding items 24-28, wherein the panel is rectangular, wherein the at least one cavity (2) intersects with a locking device (6a; 6b) arranged on a long edge portion (1a', 1b') and / or a short edge portion (1c', 1d') of the panel.

[0250] Item 30. The panel according to any one of the preceding items 24 to 29, comprising a core (8a) and a decorative structure (8b), such as a decorative layer (8c) and / or a wear layer (8d).

[0251] Item 31. A panel according to any one of the preceding items 24-30, wherein any layer (8; 8a, 8b, 8c, 8d, 8e, 8f), some layers or each layer comprises a thermoplastic material (4), the thermoplastic material comprising a thermoplastic polymer (4a) and preferably also a filler (4b), the thermoplastic polymer being, for example, PVC.

[0252] Item 32. The panel according to any of the preceding items 24-31, wherein the surface of the inner part (2f) of the at least one cavity (2) is closed.

[0253] Item 33. A panel according to any one of the preceding items 24-32, wherein the at least one cavity (2) is elongated, and the ratio between its longitudinal extension length (LE) and its transverse extension length (TE) is 1<LE / TE≤150, for example 6≤LE / TE≤120, preferably 10≤LE / TE≤100.

[0254] Item 34. A panel according to any one of the preceding items 24-33, wherein the at least one cavity (2) has substantially the same extension length along a pair of non-parallel horizontal directions (D1, D2), the pair of non-parallel horizontal directions being, for example, a pair of perpendicular horizontal directions.

[0255] Item 35. A panel according to any one of the preceding items 24-34, wherein, for the depth (DC) of the plurality of cavities (2), the depth of the cavities at the long edge portions (1a', 1b') and / or the short edge portions (1c', 1d') of the panel is smaller than the depth of the cavities in the interior (5a) of the back side (5).

[0256] Item 36. A panel according to any one of the preceding items 24-35, wherein a first group (2m) and a second group (2n; 2n') in a cavity (2) are separated from each other by a partition (5b; 5b') along a panel direction (PD; PD'), and an inter-cavity distance (K2; K2') between the first group and the second group along the panel direction (PD; PD') is greater than an inter-cavity distance (K1; K1') within each of the first group and the second group.

[0257] Item 37. The panel according to any of the preceding items 24-36, further comprising a backing layer (8e), wherein the backing layer is continuous at least at the location of the at least one cavity (2).

[0258] Item 38. A method for manufacturing a plate element (1), the plate element comprising at least one cavity (2), preferably a plurality of cavities, on its back side (5), wherein the method comprises:

[0259] providing a substrate (3) comprising a thermoplastic material (4), wherein the substrate comprises a substrate portion (3a);

[0260] The plate element (1) is obtained by creating the at least one cavity (2) on the back side (3b) of the substrate (3) by embossing the substrate portion (3a) via an embossing device (10) comprising at least one protruding embossing element (9); and

[0261] After creating the at least one cavity (2), the plate element (1) is annealed.

[0262] Item 39. A method according to Item 38 and according to any one of the preceding Items 2-21.

[0263] Item 40. A method for manufacturing a plate element (1) comprising a plurality of cavities on its back side (5), wherein the method comprises:

[0264] providing a substrate (3) comprising a thermoplastic material (4), wherein the substrate comprises a substrate portion (3a); and

[0265] The plate element (1) is obtained by creating a cavity (2) on the back side (3b) of the substrate (3) by embossing a substrate portion (3a) via an embossing device (10) comprising at least one protruding embossing element (9),

[0266] wherein a first group (9g) and a second group (9h; 9h') of the embossing elements (9) are separated from each other along a separation direction (S1; S2) by a blank portion (10e; 10f), and an inter-embossing element distance (L2; L2') between the first group and the second group along the separation direction (S1; S2) is greater than an inter-embossing element distance (L1; L1') within each of the first group and the second group,

[0267] The first group (2m) and the second group (2n; 2n') in the cavity (2) are separated from each other along the panel direction or the board direction (PD; PD') by a partition (5b; 5b'), and the inter-cavity distance (K2; K2') between the first group and the second group along the panel direction or the board direction (PD; PD') is greater than the inter-cavity distance (K1; K1') within each of the first group and the second group.

[0268] Item 41. A method according to Item 40 and according to any one of the preceding Items 2-22.

Claims

1. A method for producing a plate element (1) comprising at least one cavity (2), preferably a plurality of cavities, on its back side (5), wherein the method comprises: Providing a substrate (3) comprising a thermoplastic material (4), wherein the substrate comprises a substrate portion (3a); as well as The plate element (1) is obtained by creating the at least one cavity (2) on the back side (3b) of the substrate (3) by embossing the substrate portion (3a) via an embossing device (10) comprising at least one protruding embossing element (9), wherein when creating the at least one cavity (2), the substrate portion (3a) is placed at an elevated temperature (TS), the elevated temperature (TS) being between 40 and 295° C., and The at least one protruding embossing element (9) is a conical embossing element, wherein the conical embossing element (9) forms a conical cavity (2).

2. The method according to claim 1, wherein: The draft angle (α) between the tapered side wall portion (9c) of the at least one embossing element (9) and the general normal direction (N) of the embossing device (10) exceeds 0.5°.

3. The method according to claim 1 or 2, wherein: The tapered embossing element (9) comprises a bevel (9a; 9b) and / or a tapered side wall portion (9c), and the tapered cavity (2) comprises a chamfer (2b; 2a) and / or a tapered cavity wall (2c).

4. The method according to any of the preceding claims further comprises forming at least one chamfer (2a, 2b) in at least one of the conical cavities (2), each chamfer being located between the cavity wall (2c) and the back side (3b; 5), or between the cavity wall (2c) and the bottom wall (2d) of the conical cavity (2).

5. A method according to any one of the preceding claims, wherein: The embossing device (10) comprises at least one roller (11).

6. The method according to any one of the preceding claims 1 to 4, wherein: The embossing device (10) comprises an embossing platen (12a) provided with a structured surface (12c) comprising the at least one protruding embossing element (9).

7. A method according to any one of the preceding claims, wherein: The elevated temperature (TS) is in the range of 100-295°C.

8. A method according to any one of the preceding claims, wherein: The elevated temperature (TS) is obtained by heating the substrate portion (3a).

9. The method according to claim 8, wherein: The elevated temperature (TS) is obtained during forming of the substrate (3) under heating and preferably pressure.

10. A method according to any one of the preceding claims, wherein: The stamping includes applying a pressure of 0.4-5.0 MPa to the substrate portion (3a).

11. The method according to any of the preceding claims, further comprising cooling at least the cavity region (2e) of the substrate (3) or of the plate element (1) during and / or after creating the at least one cavity (2).

12. The method according to claim 11, wherein: The cavity region (2e) is cooled to a cooling temperature (Tc) in the range of 0.8 to 1.9 times the glass transition temperature (Tg) of the thermoplastic material (4), wherein the cooling temperature (Tc) and the glass transition temperature (Tg) are expressed in Kelvin.

13. The method according to any of the preceding claims, further comprising supporting at least an inner portion (2f) of at least one cavity (2) created during lamination of the layer (8) onto the plate element (1) and / or during cooling of at least the cavity area (2e) of the plate element (1).

14. The method according to any of the preceding claims, further comprising pre-forming the substrate (3) before creating the at least one cavity (2).

15. A method according to any one of the preceding claims, wherein: The board element (1) is provided in the form of a panel (1') or the board element (1) can be divided into at least one panel, for example at least two panels, each panel being a building panel, a floor panel, a wall panel, a ceiling panel or a furniture component.

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