Building panel with a mechanical locking device and a method of producing such a building panel

Description

A building panel with a mechanical locking device and a method for producing such a building panel. FIELD OF TECHNIQUE

[001] The present description refers to the field of building panels, especially floor or wall panels, and methods of production of such panels. BACKGROUND OF THE TECHNIQUE

[002] In the field of building panels, there are a number of different boards to form the backing board of the building panel. One example is a fiberboard. It is a wood composite that is prepared by mixing wood fibers with thermosetting resin. The fiberboard is then hot-pressed. Fiberboards can be produced with different densities, and a fiberboard with a density of approximately 600-800 kg / m3 is referred to as a Medium Density Fiberboard (MDF) and a fiberboard with a density of approximately 800-1000 kg / m3 is referred to as a High Density Fiberboard (HDF). MDF is commonly used in the furniture industry as a substitute for solid wood, and HDF is commonly used in the flooring industry.Most wood fibers, in both MDF and HDF, are long, thin, refined fibers with an aspect ratio, that is, a ratio between the length of the fiber and its width, of above 40 and sometimes as much as approximately 100.

[003] Another example of a board is particleboard, which may include a similar raw material such as fiberboard, i.e., wood-based materials. One difference between the two types of board is that the density of particleboard is lower, between 500-750 or approximately 650 kg / m3. Another difference is that the wood material being used for the production of particleboard is usi Petition 870250085634, dated 09 / 22 / 2025, page 9 / 117 2 / 84 made from wood chips of different sizes and not refined into fibers, as in the production of fiberboard.

[004] Both of the above-mentioned boards, however, are not ideal for the development that the building panel industry, and perhaps even more so the flooring industry, is facing, especially when it comes to panels that are more or completely water-resistant, lighter and thinner products, in order to reduce material consumption or lower manufacturing costs as material prices increase.

[005] In order to create a more water-resistant building panel, the market has attempted to incorporate or even migrate to thermoplastic materials, such as PVC, or has used different types of fillers, such as kaolin clay or limestone. Such panels fall within the field referred to as LVT, SPC, or WPC. The disadvantages of such panels may be that they are quite expensive and sensitive to temperature. Furthermore, the ongoing debate about whether thermoplastics, such as PVC, are not environmentally friendly may also be a disadvantage.

[006] All the above boards can then be combined with various surface materials in order to produce a building panel with a decorative surface. Such surface material can be paper impregnated with thermosetting resin, thermoplastic sheets, wood veneer or a layer of printed decorative powder. In order to balance a building panel that has a surface layer, the same type of surface layer is preferably placed on the back side of the building panel as well, which is known in the art.

[007] It is known in the field to apply a surface layer to a plate, usually also with a suitable binder between the plate and the surface layer, and to apply heat and pressure to form Petition 870250085634, dated 09 / 22 / 2025, page 10 / 117 3 / 84 of the construction panel. This can be done in a continuous pressing device or in a discontinuous pressing device, by a single pressing device or multiple pressing devices.

[008] Wood-based building panels are sensitive to moisture, and one problem is that the edges between two building panels expand when exposed to water. Furthermore, the bond between the wood particles can be damaged, and the initially compressed wood particles can expand. The expansion becomes permanent because there is nothing to compress the particles again when they dry after the building panels are installed. Expansion, especially edge expansion, can, for example, lead to a greater risk of damaging wear on the building panel, especially if the building panel is a floor panel. SUMMARY

[009] An object of at least some embodiments of the present description is to provide improvements with respect to known technique. This object can be achieved by a technique defined in the appended independent claims; a certain embodiment being presented in the relative dependent claims.

[0010] Another objective of at least some embodiments of the present description is to reduce the production time and increase the production efficiency of producing a building panel.

[0011] Yet another object of at least some embodiments of the present description is to increase the water resistance of a building panel comprising lignocellulosic particles.

[0012] An additional objective of at least some embodiments of the description is to increase the control and adaptability of the construction panel structure so that it can be combined with different types Petition 870250085634, dated 09 / 22 / 2025, page 11 / 117 4 / 84 of mechanical locking devices.

[0013] In a first aspect of the present description, a method is provided for producing a building panel, such as a floor panel or wall panel, the method comprising providing a back-side layer comprising a first mixture of at least lignocellulosic particles and a binder, applying an intermediate layer comprising a second mixture of at least lignocellulosic particles and a binder to the back-side layer, applying a front-side layer comprising a third mixture of at least lignocellulosic particles and a binder to the intermediate layer, wherein an average particle size in the second mixture is larger than an average particle size in the first and / or third mixture, and applying pressure and heat to form said building panel.The method further comprises creating a mechanical locking device along at least one edge of the construction panel, wherein the mechanical locking device is configured for horizontal and / or vertical locking of similar or essentially identical construction panels in an assembled position. The mechanical locking device comprises an upper surface, which is disposed in a front-side area of ​​at least one edge portion and which extends in a direction essentially parallel to a top surface, along at least one edge portion of the construction panel, offset from said upper surface, wherein the upper surface is disposed in the front-side layer.

[0014] In one embodiment, the mechanical locking device further comprises a locking strip with a locking element, which is disposed in a rear side area of ​​at least one edge portion and which extends in a direction essentially parallel to a rear surface, along at least Petition 870250085634, dated 09 / 22 / 2025, page 12 / 117 5 / 84 a portion of the construction panel edge, where the locking strip and locking element are created at least partially in the back side layer.

[0015] At least 60% or at least 80% of the locking strip and locking element can be created on the back side layer.

[0016] In one embodiment, the front side layer is the top layer comprising said top surface of the construction panel.

[0017] The method may also involve creating a pattern on the top surface of the front side layer simultaneously with the application of pressure and heat to form the construction panel.

[0018] In another embodiment, a front-side element is applied to the subsequent front-side layer by applying pressure and heat to form said construction panel.

[0019] In yet another embodiment, the method further comprises, before applying pressure and heat to form the construction panel, providing a back-side element onto which the first mixture is applied, creating the back-side layer, and / or applying a front-side element over the front-side layer, where the front-side layer adheres to the front-side element and the back-side layer adheres to the back-side layer when pressure and heat are applied.

[0020] In one embodiment, the back side element and / or the front side element is a wood veneer element.

[0021] In another embodiment, the back side element and / or the front side element is a sheet of paper, an unimpregnated sheet of paper or an impregnated sheet of paper.

[0022] The method may also comprise creating a pattern on an upper surface of the front-side element, simultaneously Petition 870250085634, dated 09 / 22 / 2025, p. 13 / 117 6 / 84 to apply pressure and heat to form the building panel.

[0023] In one embodiment, the third mixture further comprises a colorant, such as a pigment, dye or chemical coloring agent.

[0024] In another embodiment, at least 50% of the lignocellulosic particles in the second mixture have an aspect ratio between 1:1 and 30:1. The aspect ratio is, here and throughout this application, the ratio of the length to the width of the fibers.

[0025] In yet another embodiment, the lignocellulosic particles of the second mixture and the lignocellulosic particles of the third mixture are mixed, at least in a boundary area between the intermediate layer and the leading-side layer.

[0026] In a second aspect of the present description, a building panel, such as a floor panel or wall panel, is provided, comprising a multilayer substrate comprising a back-side layer comprising lignocellulosic particles and a binder, an intermediate layer comprising lignocellulosic particles and a binder, arranged on the back-side layer, and a front-side layer comprising lignocellulosic particles and a binder, arranged on the intermediate layer. The back-side layer was formed from a first mixture, the intermediate layer was formed from a second mixture, and the front-side layer was formed from a third mixture, wherein an average particle size in the second mixture is larger than an average particle size in the first and / or third mixture.The construction panel further comprises a mechanical locking device disposed along at least one edge portion of the construction panel, wherein the mechanical locking device is configured for horizontal and / or vertical locking of similar or essentially identical construction panels in an assembled position. The mechanical locking device comprises an upper surface, which... Petition 870250085634, dated 09 / 22 / 2025, page 14 / 117 7 / 84 is disposed in a front-side area of ​​at least one edge portion and which extends in a direction essentially parallel to an upper surface, along at least one edge portion, of the construction panel, offset from said upper surface, where the upper surface is still disposed in the front-side layer of the construction panel.

[0027] In one embodiment, the mechanical locking device further comprises a locking strip with a locking element, which is disposed in a rear side area of ​​at least one edge portion and which extends in a direction essentially parallel to a rear surface, along at least one edge portion, of the construction panel, where the locking strip and the locking element are disposed at least partially in the rear side layer of the construction panel.

[0028] The locking strip and the locking element are arranged on the back side layer, such that at least 60% or at least 80% of the locking strip and the locking element are arranged on the back side layer.

[0029] In one embodiment, the front side layer is the top layer comprising said top surface of the construction panel.

[0030] The construction panel may further comprise a back side element to which the back side layer is attached and / or a front side element to which the front side layer is attached.

[0031] In one embodiment, the back side element and / or the front side element are wood veneered.

[0032] In another embodiment, the back side element and / or the front side element are a sheet of paper, an unimpregnated sheet of paper or an impregnated sheet of paper.

[0033] In yet another form, lignocellulosic particles of Petition 870250085634, dated 09 / 22 / 2025, page 15 / 117 8 / 84 second mixture and lignocellulosic particles from the third mixture are mixed, at least in a boundary area between the intermediate layer and the leading-side layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The embodiments of the present description will be described below: reference may be made to the accompanying drawings, which illustrate non-limiting embodiments of how the present description may be put into practice.

[0035] Figure 1 is a schematic illustration of a method for producing a construction panel according to an embodiment of the present description,

[0036] Figure 2 is a schematic illustration of a method for producing a construction panel according to another embodiment of the present description,

[0037] Figure 3A is a schematic illustration of a continuation of the methods illustrated in Figures 1 and 2, according to an embodiment of the present description,

[0038] Figure 3B is a schematic illustration of another continuation of the methods illustrated in Figures 1 and 2, according to an embodiment of the present description,

[0039] Figure 4 is a schematic illustration of a method for producing a construction panel according to an embodiment of the present description,

[0040] Figure 5 is a schematic illustration of a method for producing a construction panel according to an embodiment of the present description,

[0041] Figure 6 is a schematic illustration of a method for producing a construction panel according to another embodiment of the present description,

[0042] Figure 7 is an illustration of an attractive cross-section Petition 870250085634, dated 09 / 22 / 2025, page 16 / 117 9 / 84 through layers in a construction panel, according to an embodiment of the present description,

[0043] Figure 8 is an illustration of a cross-section through layers in a building panel, according to another embodiment of the present description,

[0044] Figure 9A is an illustration of a cross-section through layers in a building panel, according to yet another embodiment of the present description,

[0045] Figure 9B is a cross-sectional photo through layers in the construction panel, as illustrated in Figure 9A,

[0046] Figure 10 is an illustration of a cross-section through a construction panel with open features, according to an embodiment of the present description,

[0047] Figure 11 is an illustration of a top view of a building panel with a mechanical locking device, according to an embodiment of the present description,

[0048] Figure 12A is an illustration of a set of three substantially identical construction panels, according to an embodiment of the present description,

[0049] Figure 12B is an illustration of the three construction panels of Figure 12A in an assembled state,

[0050] Figure 13A is an illustration of a cross-section of a mechanical locking device, according to an embodiment of the present description, in an assembled state, arranged along opposite edges of two adjacent construction panels,

[0051] Figure 13B is an illustration of a cross-section of a mechanical locking device, according to another embodiment of the present description, in an assembled state, arranged along opposite edges of two adjacent construction panels,

[0052] Figure 14 is an illustration of a top view of a Petition 870250085634, dated 09 / 22 / 2025, p. 17 / 117 10 / 84 movable locking tongue, according to one embodiment of the present description, for a mechanical locking device,

[0053] Figure 15A is an illustration of a cross-section of a building panel, according to another embodiment of the present description, in an assembled state, arranged along opposite edges of two adjacent panels,

[0054] Figure 15B is an illustration of a cross-section of a construction panel, according to yet another embodiment of the present description, in an assembled state, arranged along opposite edges of two adjacent panels,

[0055] Figure 16 is a diagram showing the results of Example 3, and

[0056] Figures 17-21 show density profiles of different types of known building panels and particleboard and fiberboard. DETAILED DESCRIPTION OF MODALITIES

[0057] Specific embodiments of the description will now be described with reference to the accompanying drawings. This invention can, however, be embodied in many different forms and should not be interpreted as limited to the embodiments presented here; rather, these embodiments are provided so that this description will be comprehensive and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, equal numbers refer to equal elements.

[0058] Generally, in this description, terms like below or lower typically imply closer to the back surface of the panel or a plane thereof, while above or upper imply closer to the front surface or a plane thereof. Petition 870250085634, dated 09 / 22 / 2025, p. 18 / 117 11 / 84 Furthermore, the panel thickness direction is defined as the vertical direction when the panel is laid flat on a surface. The horizontal and vertical directions are applicable when the construction panel is laid flat, for example, on a floor. Instead of horizontal and vertical directions, the description will also refer to a direction parallel to the extent of the decorative surface and a direction perpendicular to the extent of the decorative surface. When a construction panel is laid flat, for example, on a floor, the horizontal direction is the same as the direction parallel to the extent of the decorative surface, and the vertical direction is the same as the direction perpendicular to the extent of the decorative surface.

[0059] Figures 1-6 illustrate different configuration possibilities and methods for producing a construction panel according to the inventive concept. Several features in the production configurations are the same. For example, each configuration has three applicator devices 2a, 2b, 2c, which are configured to each apply a mixture 13a, 13b, 13c. The applicator devices 2a, 2b, 2c can spread the mixtures or roll over the mixtures, i.e., they can operate at a distance from where the mixtures are applied or be in contact with where the mixtures are applied. The applicator devices 2a, 2b, 2c can also be configured to handle mixtures of any form, i.e., mixtures, for example, in dry form or wet form.

[0060] Each configuration still has at least one construction panel forming device 4a, 4b, which is configured to apply both heat and pressure to form a construction panel. In the illustrated example, two opposing construction panel forming devices 4a, 4b are shown, where one is arranged on the front side and the other is arranged on the back side. Both can be configured to apply both pressure and heat, but it is also Petition 870250085634, dated 09 / 22 / 2025, page 19 / 117 12 / 84 It is possible that there is a difference between the two construction panel forming devices 4a, 4b, for example, one may be configured to apply both heat and pressure, while the other is only configured to apply pressure. In the illustrated example, the construction panel forming devices 4a, 4b are continuous devices operating in the feed direction F. In another embodiment (not illustrated), the construction panel forming devices may be discontinuous devices, such as a static device.

[0061] The first applicator device 2a is configured to apply a first mixture 13a to form a back side layer 15 of a construction panel 10. In Figures 1-2 and 4-5, the first mixture 13a is applied onto a support 6, such as a loader belt or conveyor belt or similar, while in Figure 6 the first mixture 13a is applied onto a back side element 11.

[0062] The first mixture 13a can be applied in dry form or wet form and, in one embodiment, can be a powder. For example, the mixture(s) can be in dry form, as well as in powder form. For example, the mixture(s) can be in wet form, such as in a mixture with water or another liquid.

[0063] The rear side layer 15 resulting from the first mixture The first mixture 13a, applied and subsequently pressed, preferably has a thickness perpendicular to the longitudinal extent of an upper surface 24 of the construction panel 10, which may be between 2 mm and 3 mm of a construction panel 10, with a total thickness of approximately 10 mm. The back side layer 15 resulting from the first mixture 13a, applied and subsequently pressed, preferably has a thickness perpendicular to the longitudinal extent of an upper surface 24 of the construction panel. Petition 870250085634, dated 09 / 22 / 2025, p. 20 / 117 13 / 84 10, which is between 20% and 30% of the total thickness of the construction panel 10.

[0064] The first mixture 13a includes at least lignocellulosic particles and a binder.

[0065] The lignocellulosic particles in the first mixture 13a may be wood particles, for example, of pine, oak, eucalyptus or other wood species, cereal straw, sisal, coconut, bamboo, hemp, flax, jute, curauá, ramie or any combination of such particles. The lignocellulosic particles constitute between 70% and 99%, above 75% or above 85% of the first mixture 13a. As is common in the timber industry, the quantities are calculated on the basis of dry weight, with the quantity of completely dry wood = 100% as the basis.

[0066] Most, that is, at least 50%, of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 0.6 mm. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 0.6 mm. In an alternative embodiment, most, that is, at least 50%, of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm.

[0067] The lignocellulosic particles in the first mixture 13a can also be measured by an aspect ratio, that is, the ratio between the particle length and its width. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles in the first mixture 13a is less than 30. Preferably, at least 60%, at least 70% or at least 80% of the lignocellulosic particles Petition 870250085634, dated 09 / 22 / 2025, p. 21 / 117 14 / 84 in the first mixture 13a have an aspect ratio of less than 30. The aspect ratio of most, i.e., at least 50%, of the lignocellulosic particles in the first mixture 13a is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. Preferably, the aspect ratio of at least 60%, at least 70%, or at least 75% of the lignocellulosic particles in the first mixture 13a is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. In one embodiment, the size of lignocellulosic particles in the first mixture 13a is between 0.3 mm and 1.25 mm, or between 0.3 mm and 0.6 mm, and with an aspect ratio of less than 20 or less than 10.

[0068] The binder in the first mixture 13a may be a thermosetting resin. Examples of suitable thermosetting resins are amino resins, such as melamine formaldehyde, urea formaldehyde, phenol formaldehyde resins or combinations thereof, or formaldehyde-free resins, such as epoxy resins, acrylic resins, polyurethane resins, diphenylmethane diisocyanate polymer resin, polyester resins or combinations thereof.

[0069] The binder constitutes between 5% and 35%, or between 10% and 25% of the first mixture 13a. As is common in the timber industry and described above, the quantities are calculated in dry weight, with the quantity of completely dry wood = 100% as the basis. The amount of binder in the first mixture 13a, or in any of the mixtures 13b, 13c in this description, can affect the water resistance or water repellency properties of the layers 15, 17, 19 of the construction panel 10, which are formed from the respective mixtures 13a, 13b, 13c. Having more binder in the mixture 13a, 13b, 13c will increase the water resistance or water repellency properties in the construction panel 10. However, the binder is also the most expensive component of the mixture, thus, an amount as defined above provides a beneficial balance between effect and cost. Petition 870250085634, dated 09 / 22 / 2025, page 22 / 117 15 / 84

[0070] The first mixture 13a may also include a hydrophobic agent, such as wax. The first mixture 13a may comprise 13% or 1-2% of the hydrophobic agent. Preferred hydrophobic agents are paraffin emulsions. An advantage of having a hydrophobic agent in the first mixture 13a, and in any of the mixtures 13b, 13c in this description, is that it provides the layers 15, 17, 19 of the construction panel 10, which are formed from the respective mixtures 13a, 13b, 13c, with improved water-repellent properties, in turn creating a more water-resistant construction panel 10. Thus, it may be beneficial to add a hydrophobic agent to mixture 13a, 13b, 13c, forming a layer 15, 17, 19 in which features to increase the water resistance properties in the building panel 10 are created. Examples of this will be described later.

[0071] The first mixture 13a may also comprise different types of additives, such as dye, catalyst (e.g., ammonium sulfate), formaldehyde scavenger (e.g., urea) or buffer solution.

[0072] The second applicator device 2b is configured to apply a second mixture 13b to form an intermediate layer 17 of the construction panel 10. In Figures 1-6, the second mixture 13b is applied over the first mixture 13a. As the second mixture 13b is applied over the first mixture 13a, particles, specifically lignocellulosic particles, from each of the back-side layer 15 and the intermediate layer 17 will mix, at least in a boundary area between the back-side layer 15 and the intermediate layer 17.

[0073] The second mixture 13b can be applied in dry or wet form and can, in one embodiment, be a powder. For example, the mixture(s) can be in dry form, such as in powder form. Petition 870250085634, dated 09 / 22 / 2025, p. 23 / 117 16 / 84 For example, the mixture(s) may be in wet form, such as in a mixture with water or another liquid.

[0074] The intermediate layer 17 resulting from the second mixture The applied and subsequently pressed 13b preferably has a thickness in the direction perpendicular to the extent of the upper surface 24 of the construction panel 10, which is between 0.9 mm and 19.6 mm of a construction panel 10, resulting in a panel with a total thickness between 4 mm and 28 mm. In one embodiment, the intermediate layer 17 resulting from the second applied and subsequently pressed 13b preferably has a thickness in the direction perpendicular to the extent of an upper surface 24 of the panel 10, which is between 3 mm and 7 mm of a construction panel 10, resulting in a panel with a total thickness of approximately 10 mm. The intermediate layer 17 resulting from the second applied and subsequently pressed 13b preferably has a thickness in the direction perpendicular to the longitudinal extent of the upper surface 24 of the construction panel 10, which is between 30% and 70% of the total thickness of the construction panel 10.

[0075] The second mixture 13b includes at least lignocellulosic particles and a binder.

[0076] The lignocellulosic particles in the second mixture 13b may be wood particles, for example, made of pine, oak, eucalyptus or other wood species, cereal straw, sisal, coconut, bamboo, hemp, flax, jute, curauá, ramie or any combination of such particles. The lignocellulosic particles constitute between 70% and 99%, above 75% or above 85% of the second mixture 13b.

[0077] Most, that is, at least 50%, of the lignocellulosic particles in the second mixture 13b have a particle size between 0.5 mm and 4 mm, or between 0.5 mm and 2.5 mm, or between 0.5 mm and 1.5 mm, or between 0.6 mm and 1.3 mm. Preferably, at least 60%, at least Petition 870250085634, dated 09 / 22 / 2025, p. 24 / 117 17 / 84 70% or at least 80% of the lignocellulosic particles in the second mixture 13b have a particle size between 0.5 mm and 4 mm, or between 0.5 mm and 2.5 mm, or between 0.5 mm and 1.5 mm, or between 0.6 mm and 1.3 mm. The lignocellulosic particles in the second mixture 13b can, as explained for the first mixture, also be measured by an aspect ratio, that is, the ratio between the particle length and its width. The aspect ratio of the majority, that is, at least 50%, of the lignocellulosic particles in the second mixture 13b is less than 30. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles in the second mixture 13b have an aspect ratio of less than 30. The aspect ratio of the majority, that is, at least 50%, of the lignocellulosic particles in the second mixture 13b is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1.Preferably, the aspect ratio of at least 60%, at least 70%, or at least 75% of the lignocellulosic particles in the second mixture 13b is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. In one embodiment, the particle size of the lignocellulosic particles in the second mixture 13b is between 0.6 mm and 1.3 mm and with an aspect ratio of less than 10. In another embodiment, the particle size of the lignocellulosic particles in the second mixture 13b is between 0.6 mm and 4 mm and with an aspect ratio of less than 10.

[0078] The binder in the second mixture 13b may be a thermosetting resin. Examples of suitable thermosetting resins are amino resins, such as melamine formaldehyde, urea formaldehyde, phenol formaldehyde or combinations thereof, or resins without added formaldehyde, such as epoxy resins, acrylic resins, polyurethane resins, diphenylmethane diisocyanate polymer resin, polyester resins or combinations thereof. The binder in the second mixture 13b may be the same binder as in the first mixture 13a.

[0079] The binder constitutes between 3% and 20%, or between 5% and 10% of Petition 870250085634, dated 09 / 22 / 2025, p. 25 / 117 18 / 84 second mixture 13b. The amount of binder in the second mixture 13b, or in any of the mixtures 13a, 13c in this description, can affect the water resistance or water repellency properties of layers 15, 17, 19 of the construction panel 10, which are formed from the respective mixtures 13a, 13b, 13c. Having more binder in mixture 13a, 13b, 13c will increase the water resistance or water repellency properties in the construction panel 10. However, the binder is also the most expensive component of the mixture, thus, an amount as defined above provides a beneficial balance between effect and cost.

[0080] The second mixture 13b may also include a hydrophobic agent, such as wax. The second mixture 13b may comprise 1-3% or 1-2% of the hydrophobic agent. Preferred hydrophobic agents are paraffin emulsions. An advantage of having a hydrophobic agent in the second mixture 13b, and in any of the mixtures 13a, 13c in this description, is that it provides the layers 15, 17, 19 of the construction panel 10, which are formed from the respective mixtures 13a, 13b, 13c, with improved water-repellent properties, in turn creating a more water-resistant construction panel 10. It may therefore be beneficial to add a hydrophobic agent to mixture 13a, 13b, 13c, which form a layer 15, 17, 19 which are characteristic to increase the water resistance properties in the construction panel 10 created. Examples of this will be described later.

[0081] The second mixture 13b may also comprise different types of additives, such as dye, catalyst (e.g., ammonium sulfate), formaldehyde scavenger (e.g., urea) or buffer solution.

[0082] The third applicator device 2c is configured to apply a third mixture 13c to form a front-side layer. Petition 870250085634, dated 09 / 22 / 2025, page 26 / 117 19 / 84 of construction panel 10. In Figures 1-6, the third mixture 13c is applied over the second mixture 13b. Because the third mixture 13c is applied over the second mixture 13b, particles, specifically lignocellulosic particles, from each of the intermediate layer 17 and the leading side layer 19 will mix, at least in a boundary area between the leading side layer 19 and the intermediate layer 17.

[0083] The third mixture 13c can be applied in dry or wet form and, in one embodiment, can be a powder. For example, the mixture(s) can be in dry form, such as in powder form. For example, the mixture(s) can be in wet form, such as in a mixture with water or another liquid.

[0084] The front side layer 19 resulting from the third mixture 13c, applied and subsequently pressed, preferably has a thickness in the direction perpendicular to the extent of an upper surface 24 of the construction panel 10, which is between 2 mm and 3 mm of a construction panel 10, with a total thickness of approximately 10 mm. The resulting front side layer 19 of the third mixture 13c, applied and subsequently pressed, preferably has a thickness in the direction perpendicular to the longitudinal extent of the upper surface 24 of the construction panel 10, which is between 20% and 30% of the total thickness of the construction panel 10.

[0085] The ratio between the amount of the third mixture 13c applied and the amount of the first mixture 13a applied is between 40:60 and 60:40, or between 45:55 and 55:45. The ratio between the amount of the third mixture 13c applied and the amount of the first mixture 13a applied is approximately 50:50.

[0086] The ratio between the amount of the second mixture applied 13b and the total quantity of the first and third mixtures applied 13a, 13c is between 70:30 and 30:70, or between 60:40 and 40:60. The ratio between the Petition 870250085634, dated 09 / 22 / 2025, page 27 / 117 20 / 84 The quantity of the first mixture applied 13a, the second mixture applied 13b, and the third mixture applied 13c can be 20-60-20%, or 25-50-25%, or 30-40-30%.

[0087] The third mixture 13c includes at least lignocellulosic particles and a binder.

[0088] The lignocellulosic particles in the third mixture 13c may be wood particles, for example, made of pine, oak, eucalyptus or other wood species, cereal straw, sisal, coconut, bamboo, hemp, flax, jute, curauá, ramie or any combination of such particles. Lignocellulosic particles constitute between 70% and 99%, or above 75%, or above 85% of the third mixture 13c.

[0089] Most, that is, at least 50%, of the lignocellulosic particles in the third mixture 13c have a particle size between 0.3 mm and 0.6 mm. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles in the third mixture 13c have a particle size between 0.3 mm and 0.6 mm. In an alternative embodiment, most, that is, at least 50%, of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm.

[0090] The lignocellulosic particles in the third mixture 13c can, as explained above, also be measured by an aspect ratio, that is, the ratio between the particle length and its width. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles in the third mixture 13c is less than 30. Preferably, at least 60%, at least 70% or at least 80% of the lignocellulosic particles in the third mixture 13c have an aspect ratio less than 30. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles in the third mixture 13c is less than 30. Petition 870250085634, dated 09 / 22 / 2025, p. 28 / 117 21 / 84 in 50% of the lignocellulosic particles in the third mixture 13c is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. Preferably, the aspect ratio of at least 60%, at least 70%, or at least 75% of the lignocellulosic particles in the third mixture 13c is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. In one embodiment, the particle size of the lignocellulosic particles in the third mixture 13c is between 0.3 mm and 1.25 mm or between 0.3 mm and 0.6 mm, and with an aspect ratio of less than 20 or less than 10.

[0091] The binder in the third mixture 13c may be a thermosetting resin. Examples of suitable thermosetting resins are amino resins, such as melamine formaldehyde, urea formaldehyde, phenol formaldehyde resins or combinations thereof, or resins without added formaldehyde, such as epoxy resins, acrylic resins, polyurethane resins, diphenylmethane diisocyanate polymer resin, polyester resins or combinations thereof. The binder in the third mixture 13c may be the same binder as in the first mixture 13a and / or the second mixture 13b.

[0092] The binder constitutes between 5% and 35%, or between 10% and 25% of the third mixture 13c. The amount of binder in the third mixture 13c, or in any of the mixtures 13a, 13b in this description, may affect the water resistance or water repellency properties of layers 15, 17, 19 of the construction panel 10, which are formed from the respective mixtures 13a, 13b, 13c. Having more binder in mixtures 13a, 13b, 13c will increase the water resistance or water repellency properties in the construction panel 10. However, the binder is also the most expensive component of the mixture, thus, an amount as defined above provides a beneficial balance between effect and cost.

[0093] The third mixture 13c may also include a hydrophobic agent, such as wax. The third mixture 13c may comprise 1 Petition 870250085634, dated 09 / 22 / 2025, p. 29 / 117 22 / 84 3% or 1-2% of the hydrophobic agent. Preferred hydrophobic agents are paraffin emulsions. An advantage of having a hydrophobic agent in the third mixture 13c, and in any of the mixtures 13a, 13b in this description, is that it provides the layers 15, 17, 19 of the construction panel 10, which are formed from the respective mixtures 13a, 13b, 13c, with improved water-repellent properties, in turn creating a more water-resistant construction panel 10. Thus, it may be beneficial to add a hydrophobic agent to the mixture 13a, 13b, 13c, forming a layer 15, 17, 19 in which features to increase the water-resistant properties of the construction panel 10 are created. Examples of this will be described later.

[0094] The third mixture 13c may also include colorant. The colorant may be a pigment, dye, or a chemical coloring agent. An example of a chemical coloring agent is iron vitriol. Having a colorant in the third mixture 13c makes it possible to control and adapt the appearance characteristics of the building panel 10. For example, if a front-side element 21, such as a front-side wood veneer element, or a top surface exhibits open features 22, such as cracks, holes, or the like, the colorant in the third mixture 13c is configured to color the open features 22 as the third mixture 13c penetrates the open features 22 and at least partially fills such open features 22 when pressure is subsequently applied.

[0095] The third mixture 13c may further comprise other types of additives, such as a catalyst (e.g., ammonium sulfate), a formaldehyde scavenger (e.g., urea), or a buffer solution.

[0096] In one embodiment, the third mixture 13c may comprise wear-resistant particles, such as oxide particles. Petition 870250085634, dated 09 / 22 / 2025, page 30 / 117 23 / 84 aluminum, or scratch-resistant particles. This may be preferred if the front side layer 19, formed from the third mixture 13c, is the top layer of the construction panel 10.

[0097] In order to further enhance the water resistance properties of the construction panel 10, the density of each layer 15, 17, 19, formed by mixtures 13a, 13b, 13c, can be adapted to the different water resistance properties designed in layers 15, 17, 19 of the construction panel 10. For example, it may be desirable, in the front side layer 19, to design water resistance characteristics of a mechanical locking device, which will be described in more detail below, and thus it may be desirable to increase the density of the front side layer 19 in order to further enhance the water resistance characteristics of such a mechanical locking device. The intermediate layer 17, however, can be designed to have no additional water resistance characteristics and therefore not require increased density.By adjusting the density of each layer—the back side layer 15, the intermediate layer 17, and the front side layer 19—it is possible to both increase the water resistance properties of the construction panel 10 where desired and reduce the risk of the construction panel 10 becoming too heavy. The weight of the construction panel 10 will also depend on the thickness of each of the components of the construction panel 10, but by being able to control and adjust the thickness, density, lignocellulosic particle size, binder quantity, etc., in each of the back side layer 15, the intermediate layer 17, and the front side layer 19, the weight of the construction panel 10 also becomes controllable.

[0098] A preferred density of the intermediate layer 17 is less than the density of the front side layer 19 and / or the back side layer 15. A preferred density of the inter layer Petition 870250085634, dated 09 / 22 / 2025, p. 31 / 117 24 / 84 intermediate 17 can be between 700-900 kg / m3, or approximately 800 kg / m3. A preferred density of the front side layer 19 can be between 800-1200 kg / m3, or between 900-1100 kg / m3. In one embodiment, the density of the intermediate layer 17 can be between 900-950 kg / m3, where the total thickness of the construction panel is approximately 10 mm.

[0099] In order to balance the construction panel 10, it is preferred that the back side layer 15, even if it does not have any additional water resistance characteristics designed therein, has the same density as the front side layer 19. Thus, the density of the back side layer 15 is substantially the same as the density of the front side layer 19. Thus, the density of the back side layer 15 can be between 800-1200 kg / m3 or between 900-1100 kg / m3.

[00100] In other embodiments of the present description, additional layers (not illustrated) may be applied before the application of heat and pressure to form the construction panel. Such layers may comprise a mixture according to any mixture described above, with at least lignocellulosic particles and a binder. If the additional layer(s) is / are also a decorative layer, the mixture may comprise a colorant. The mixture may be applied in dry or wet form and, in one embodiment, may be a powder. The mixture may be applied in any of the quantities described above. In one embodiment, an additional layer may be a coating layer. In another embodiment, an additional layer may comprise wear-resistant particles, such as aluminum oxide particles, or scratch-resistant particles. This may be preferred if the additional layer is a top layer of the construction panel.

[00101] There are, however, some differences in the settings Petition 870250085634, dated 09 / 22 / 2025, page 32 / 117 25 / 84 among the production methods, as illustrated in Figures 1-6. Each method is, however, possible in order to obtain a construction panel 10 according to the present inventive concept.

[00102] In Figure 1, the first mixture 13a is applied onto a support 6, in the illustrated example, a conveyor belt. Once the first mixture 13a, the second mixture 13b and the third mixture 13c have been applied, layers 15, 17, 19 of mixtures 13a, 13b, 13c are transferred to the construction panel forming devices 4a, 4b, where pressure and heat are applied to form the construction panel 10. The pressure and heat are preferably applied by a combined heat and pressure device, such as the construction panel forming device 4a, 4b. In the examples illustrated in Figures 1-6, there is a combined heat and pressure device 4a, 4b on each opposite side of the construction panel 10. The heat and pressure devices 4a, 4b are also illustrated as continuous heat and pressure devices feeding the construction panel 10 in the feed direction F.

[00103] In alternative configurations, the heat and pressure devices may be discontinuous devices. It is also possible to have only a single heat and pressure device instead of a double one, as illustrated. Also, it is possible to have a combined heat and pressure device operating on one side of the construction panel and a pressure device, without additional heat, operating on the opposite side of the construction panel.

[00104] When forming the construction panel 10 in a continuous pressing device, a pressure between 20-80 bar, between 40-80 bar, between 50-70 bar, approximately 50 bar or approximately 60 bar is applied, which is applied at a pressing factor between 6-16 s / mm, between 7-14 s / mm or between 8-12 s / mm. Furthermore, a temperature on the pressing plate between 120-250°C, between 130-200°C or Petition 870250085634, dated 09 / 22 / 2025, page 33 / 117 26 / 84 approximately 160-180°C is applied.

[00105] In one embodiment, the method of forming the construction panel 10 may further include creating a pattern on the top surface of the front side layer 19, simultaneously with the application of pressure and heat to form the construction panel 10. This can be achieved, for example, by a structured pressing plate (not shown) in the heating and pressing device 4a, or with a movable pressing sheet (not shown) which can be disposed between the front surface of the front side layer 19 and the heating and pressure device 4a. With such a feature in the method, it is possible to obtain a desirable and attractive structure or different levels of gloss on the top surface.

[00106] After the construction panel 10 has been formed by the heat and pressure devices 4a, 4b, the back side layer 15, the intermediate layer 17 and the front side layer 19, more specifically the binder of each layer 15, 17, 19, are cured.

[00107] After the construction panel 10 has been heated and pressed, the method may further comprise a cooling device (not shown). The cooling device is configured to control the cooling process of the formed construction panel and to prevent the construction panel from changing shape and creating undesirable forces within and between the layers of the construction panel.

[00108] In Figure 2, the method of Figure 1 is illustrated, but with the addition of a pre-pressing method step. Everything described above with reference to Figure 1 also applies to the method illustrated in Figure 2.

[00109] If further layer(s) are applied, as described above, the pre-pressing step may be performed before or after such additional layer(s) are applied.

[00110] In a modality, there may be more than one stage of Petition 870250085634, dated 09 / 22 / 2025, page 34 / 117 27 / 84 pre-pressing.

[00111] The addition of the pre-pressing method step is arranged before layers 15, 17, 19 formed by mixtures 13a, 13b, 13c enter the construction panel forming devices 4a, 4b. The pre-pressing method step is achieved by a pressing device 8, in the illustrated example, a continuous pressing device. The pressing device 8 is configured to press unwanted air out of the first mixture 13a, the second mixture 13b, and the third mixture 13c, so that unwanted air is not contained and trapped within the back side layer 15, the intermediate layer 17, and the front side layer 19 when mixtures 13a, 13b, 13c, more specifically the binders of mixtures 13a, 13b, 13c, are cured. Pressing device 8 is not configured to cure the binders of mixtures 13a, 13b, 13c, or at least it is not configured to fully cure the binders of mixtures 13a, 13b, 13c.The pressing device 8 is arranged after the third mixture 13c has been applied to the second mixture 13b.

[00112] Figure 3A illustrates a possible continuous process of the construction panel 10 after the front side layer 15, the intermediate layer 17 and the back side layer 19 have been formed in the heat and pressure devices 4a, 4b, as illustrated in Figures 1 and 2. The method may also include applying a front side element 21 after the heat and pressure application step. Before the front side element 21 is applied, it is preferred to add, for example, an adhesive 7a, such as glue or similar, to the top surface of the front side layer 19. The adhesive 7a can be applied by means of a second applicator device 7, which is disposed before the front side element 21 is applied over the front side layer 19. The front side element 21 can be chosen from a group of a wood veneer element, a sheet of paper, a sheet Petition 870250085634, dated 09 / 22 / 2025, page 35 / 117 28 / 84 of resin-impregnated paper or a non-impregnated paper sheet, a cork element, a polymer-based sheet, a pre-fabricated powder-based sheet, a powder layer comprising wood fibers and a binder, a sheet such as a thermoplastic sheet, or a coating layer such as a lacquer. In one embodiment, such a front-side element 21 is configured to receive a print. Any of the aforementioned front-side elements may further be combined with a suitable wear layer, such as a lacquer, an overlay sheet, or any other layer comprising, for example, wear-resistant particles such as aluminum oxide particles, and / or scratch-resistant particles.

[00113] Figure 3B illustrates another possible continuous process of the construction panel 10 after the front side layer 15, the intermediate layer 17 and the back side layer 19 have been formed and the binders of layers 15, 17, 19 have been cured in the heat and pressure devices 4a, 4b, as illustrated in Figures 1 and 2. The method may further include applying a top layer 7a, which may be decorative, functional and / or protective. For example, a decorative surface, such as a painted surface which is capable of receiving a print, a coating layer, such as a lacquered layer or a combination of such layers, after the heat and pressure application step. The top layer 7a may be applied by means of a second applicator device 7.

[00114] In Figure 4, the first mixture 13a is applied to a support 6, in the illustrated example, a conveyor belt. Once the first mixture 13a, the second mixture 13b, and the third mixture 13c have been applied, a rear-side element 11 and a front-side element 21 are introduced. The first mixture 13a, the second mixture 13b, and the third mixture 13c are transferred Petition 870250085634, dated 09 / 22 / 2025, page 36 / 117 29 / 84 of the back side element 11, so that the first mixture 13a is applied to the back side element 11. The front side element 21 can be chosen from a group of a wood veneer element, a sheet of paper, a sheet of paper impregnated with resin or a sheet of paper not impregnated, a cork element, a polymer-based sheet, a pre-fabricated powder-based sheet, a powder layer comprising wood fibers and a binder, a sheet, such as a thermoplastic sheet, or a coating layer, such as a lacquer. In one embodiment, such a front side element 21 is configured to receive a print.Any of the aforementioned front-side elements can also be combined with a suitable wear layer, such as a lacquer, a coating layer, or any other layer comprising, for example, wear-resistant particles such as aluminum oxide particles, and / or scratch-resistant particles.

[00115] The back-side element 11 can be a balance layer. The back-side element 11 can be a balance layer which is chosen to match the front-side element 21, that is, if the front-side element 21 is a wood veneer element, the back-side layer 11 can be a wood veneer element in order to create symmetry in the construction panel 10, or if the front-side element 21 is a sheet of paper, the back-side layer 11 can be of the same type of paper sheet for the same reason. However, it may be possible to choose a back-side element 11 that does not match the front-side element 21.

[00116] Furthermore, the front side element 21 is applied over the third mixture 13c.

[00117] After the front side element 21 and the side element Petition 870250085634, dated 09 / 22 / 2025, p. 37 / 117 30 / 84 rear 11 being in place, pressure and heat are applied to form the construction panel 10. The pressure and heat are preferably applied by a combined heat and pressure device, such as the construction panel forming device 4a, 4b. In the examples illustrated in Figures 1-6, there is a combined heat and pressure device 4a, 4b on each opposite side of the construction panel 10. The heat and pressure devices 4a, 4b are also illustrated as continuous heat and pressure devices feeding the construction panel 10 in the feed direction F.

[00118] In alternative configurations, the heat and pressure devices may be discontinuous devices. It is possible to have only a single heat and pressure device instead of a double one, as illustrated. Also, it is possible to have a combined heat and pressure device operating on one side of the construction panel and a pressure device, without added heat, operating on the opposite side of the construction panel.

[00119] As previously described, when forming the construction panel 10 in a continuous pressing device, a pressure between 20-80 bar, between 40-80 bar, between 50-70 bar, or approximately 50 bar, or approximately 60 bar, is applied, which is applied at a pressing factor between 6-16 s / mm, between 7-14 s / mm or between 8-12 s / mm. Furthermore, a temperature on the pressing plate between 120-250°C, between 130-200°C, or approximately 160-180°C is applied.

[00120] In one embodiment, the method of forming the construction panel 10 may further include creating a pattern on the upper surface of the front-side element 21, simultaneously with the application of pressure and heat to form the construction panel 10. This can be achieved, for example, by a structured pressing plate (not shown) in the heat and pressure device 4a, or with a movable pressing sheet (not shown) which can be disposed between Petition 870250085634, dated 09 / 22 / 2025, page 38 / 117 31 / 84 the front surface of the front side element 21 and the heat and pressure device 4a. Having such a feature in the method, it is possible to obtain a desirable and attractive structure, or different levels of gloss on the top surface.

[00121] After the construction panel 10 has been formed by the heat and pressure devices 4a, 4b, the back side layer 15, the intermediate layer 17 and the front side layer 19, more specifically the binders of layers 15, 17, 19, are cured.

[00122] Furthermore, the front side layer 19 is attached to the front side element 21 and the back side layer 15 is attached to the back side element 11. Moreover, the front side layer 19 has penetrated the open features 22, if any are present, of the front side element 21. The open features 22 may be cracks, holes, pores, etc. The front side layer 19 penetrates and at least partially fills such open features 22 when heat and pressure are applied. It may be preferred that the front side layer 19 completely fills the open features 22 of the front side element 21.

[00123] After the construction panel 10 has been heated and pressed, the method may further comprise a cooling device (not shown). The cooling device is configured to control the cooling process of the formed construction panel and to prevent the construction panel from changing shape and creating undesirable forces within and between the layers of the construction panel.

[00124] In Figure 5, the method of Figure 4 is illustrated, but with the addition of a pre-pressing method step. Everything described above with reference to Figure 4 also applies to the method as illustrated in Figure 5.

[00125] The addition of the pre-pressing method step is preferably arranged before the front side element 21 and the element of Petition 870250085634, dated 09 / 22 / 2025, page 39 / 117 32 / 84 back side 11 to be applied. The pre-pressing method step is achieved by a pressing device 8, in the illustrated example, a continuous pressing device. The pressing device 8 is configured to press out unwanted air from the first mixture 13a, the second mixture 13b, and the third mixture 13c, so that the unwanted air is not contained and trapped in the back side layer 15, the intermediate layer 17, and the front side layer 19 when the mixtures 13a, 13b, 13c, more specifically the binders of the mixtures 13a, 13b, 13c, are cured. The pressing device 8 is not configured to cure the binders of the mixtures 13a, 13b, 13c, or at least it is not configured to completely cure the binders of the mixtures 13a, 13b, 13c. The pressing device 8 is arranged after the third mixture 13c has been applied to the second mixture 13b.An additional advantage of the pre-pressing method step, besides removing unwanted air from mixtures 13a, 13b, 13c, is that the mixtures after the pre-pressing method step can be easier to handle and easier to transfer from the support 6 to the back side element 11 before the construction panel is formed.

[00126] In Figure 6, the first mixture 13a, unlike what is illustrated in Figures 4 and 5, is applied directly onto the rear side element 11. The rear side element 11 is then transported on the support 6, i.e., the conveyor belt in the illustrated example, together with the first mixture 13a, the second mixture 13b and the third mixture 13c applied, before the front side element 21 is applied to the third mixture 13c and transferred to the combined heat and pressure devices 4a, 4b to form the construction panel 10.

[00127] As in Figure 4, after the front-side element 21 is in place, pressure and heat are applied to form the panel. Petition 870250085634, dated 09 / 22 / 2025, page 40 / 117 33 / 84 of construction 10. Pressure and heat are preferably applied by combined heat and pressure devices 4a, 4b.

[00128] In alternative configurations, the heat and pressure devices may be discontinuous devices. It is also possible to have only a single heat and pressure device instead of a double one, as illustrated. Also, it is possible to have a combined heat and pressure device operating on one side of the construction panel and a pressure device, without additional heat, operating on the opposite side of the construction panel.

[00129] When forming the construction panel 10 in a continuous pressing device, a pressure between 20-80 bar, between 40-80 bar, between 50-70 bar, or approximately 50 bar, or approximately 60 bar is applied, which is applied at a pressing factor between 6-16 s / mm, between 7-14 s / mm or between 8-12 s / mm. Furthermore, a temperature on the pressing plate between 120-250°C, between 130-200°C or approximately 160-180°C is applied.

[00130] In one embodiment, the method of forming the construction panel 10 may further include creating a pattern on the upper surface of the front-side element 21 simultaneously with the application of pressure and heat to form the construction panel 10. This can be achieved, for example, by a structured pressing plate (not shown) in the heat and pressure device 4a, or with a movable pressing sheet (not shown) which can be disposed between the front surface of the front-side element 21 and the heat and pressure device 4a. Having such a feature in the method, it is possible to obtain a desirable and attractive structure, or different levels of gloss on the upper surface.

[00131] After the construction panel 10 has been formed by the heat and pressure devices 4a, 4b, as the construction panel forming device, the back side layer 15, the inner layer Petition 870250085634, dated 09 / 22 / 2025, page 41 / 117 34 / 84 median layer 17 and front side layer 19, more specifically the binders of layers 15, 17, 19, are cured. Furthermore, the front side layer 19 is fixed to the front side element 21 and the back side layer 15 is fixed to the back side element 11. Moreover, the front side layer 19 has penetrated the open features 22, if any are present, of the front side element 21. The open features 22 may be cracks, holes, pores, etc. The front side layer 19 penetrates and at least partially fills such open features 22 when heat and pressure are applied. It may be preferred that the front side layer 19 completely fills the open features 22 of the front side element 21.

[00132] After the construction panel 10 has been heated and pressed, the method may further comprise a cooling device (not shown). The cooling device is configured to control the cooling process of the formed construction panel and to prevent the construction panel from changing shape and creating undesirable forces within and between the layers of the construction panel.

[00133] For the embodiment illustrated in Figure 6, it may also be possible and preferable to add the pre-pressing method step, as described with reference to Figure 5 above, in order to remove unwanted air from mixtures 13a, 13b, 13c. The pressing device (not shown in this embodiment) can then be arranged after the third mixture 13c has been applied and before the front side element 21 has been applied to the third mixture 13c.

[00134] In one embodiment (not illustrated), additional dispersing devices may be used to apply a powder layer as the back-side element, or front-side element, or both. Such a powder layer may comprise at least wood-based particles and a binder, preferably also a decorative feature, such as a color. Petition 870250085634, dated 09 / 22 / 2025, p. 42 / 117 35 / 84

[00135] Figure 7 is a schematic illustration of a cross-section of a construction panel 10 formed by any of the methods illustrated in Figures 1 and 2.

[00136] Figure 8 is a schematic illustration of a cross-section of a construction panel 10 formed by any of the methods illustrated in Figures 1 and 2 with any of the additional method steps illustrated in Figures 3A and 3B.

[00137] Figure 9A is a schematic illustration of a cross-section of a construction panel 10 formed by any of the methods illustrated in Figures 4-6 and Figure 9B is a photo showing the cross-section as described.

[00138] Figure 10 is a schematic illustration of a construction panel 10 formed by any of the methods illustrated in Figures 4-6, where there are open features 22 in the front side element 21 of the construction panel 10.

[00139] The differences between the construction panels 10 in Figures 7-10 are the presence of a front side element 21 and / or a back side element 11 and the way in which such front side element 21 and / or back side element 11 is attached to the front side layer 19 and / or the back side layer 15.

[00140] However, many other features are the same in all construction panels 10, such as the multi-layer substrate 14 with the back side layer 15, the intermediate layer 17, the front side layer 19 and the two boundary areas 18a and 18b.

[00141] As explained above, the back-side layer 15 was formed from the first mixture 13a and includes at least lignocellulosic particles 15a and a binder 15b. The intermediate layer 17 was formed from the second mixture 13b and includes at least lignocellulosic particles 17a and a binder 17b. The front-side layer 19 was formed Petition 870250085634, dated 09 / 22 / 2025, p. 43 / 117 36 / 84 of the third mixture 13c and includes at least lignocellulosic particles 19a and a binder 19b.

[00142] Between the back-side layer 15 and the intermediate layer 17, respectively between the intermediate layer 17 and the front-side layer 19, there is a boundary area 18a, 18b between the layers in which the lignocellulosic particles 15a, 17a, 19a and, occasionally, also the binder 15b, 17b, 19b of the respective layers 15, 17, 19 have been mixed. That is, in a lower boundary area 18a, which may also be called a lower transition area, at least the lignocellulosic particles 15a, 17a of the back side layer 15 and the intermediate layer 17 are mixed, and in an upper boundary area 18b, which may also be called an upper transition area, at least the lignocellulosic particles 17a, 19a of the intermediate layer 17 and the front side layer 19 are mixed.

[00143] As described above, the back side layer 15 is made from the first mixture 13a, therefore, the back side layer 15 includes at least the lignocellulosic particles 15a and the binder 15b. The lignocellulosic particles 15a can be wood particles, for example, made from pine, oak, eucalyptus or other wood species, cereal straws, sisal, coconut, bamboo, hemp, flax, jute, curauá, ramie or any combination of such particles. The lignocellulosic particles 15a constitute between 70% and 99%, above 75% or above 85% of the back side layer 15.

[00144] Most, that is, at least 50%, of the lignocellulosic particles 15a in the back side layer 15 have a particle size between 0.3 mm and 0.6 mm. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles 15a in the back side layer 15 have a particle size between 0.3 mm and 0.6 mm. In an alternative embodiment, most, that is, at least Petition 870250085634, dated 09 / 22 / 2025, p. 44 / 117 37 / 84 in 50% of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm.

[00145] The lignocellulosic particles 15a in the back side layer 15 can also be measured by an aspect ratio, that is, the ratio between the particle length and its width. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles 15a is less than 30. Preferably, at least 60%, at least 70% or at least 80% of the lignocellulosic particles 15a have an aspect ratio of less than 30 or less than 10. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles 15a in the back side layer 15 is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. Preferably, the aspect ratio of at least 60%, at least 70%, or at least 75% of the lignocellulosic particles 15a is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1.At least 50% of the lignocellulosic particles 15a in the back side layer 15 have a particle size between 0.3 mm and 1.5 mm, or between 0.3 mm and 0.6 mm, and an aspect ratio of less than 30 or less than 20. In one embodiment, the particle size of the lignocellulosic particles 15a in the back side layer 15 is between 0.3 mm and 1.25 mm, or between 0.3 mm and 0.6 mm, and with an aspect ratio of less than 10.

[00146] The binder 15b in the back side layer 15 may be a thermosetting resin. Examples of suitable thermosetting resins are amino resins, such as melamine formaldehyde resins, urea formaldehyde resins, phenol formaldehyde resins or combinations thereof, or resins without added formaldehyde, such as epoxy resins, acrylic resins, polyurethane resins, polymer resins Petition 870250085634, dated 09 / 22 / 2025, p. 45 / 117 38 / 84 ca of diphenylmethane diisocyanate, polyester resins or combinations thereof.

[00147] Binder 15b constitutes between 5% and 35%, or between 10% and 25% of the back side layer 15. The amount of binder 15b in the back side layer 15, or in any of the layers 17, 19 in this description, can affect the water resistance or water repellency properties of layers 15, 17, 19 of the construction panel 10. Having more binder in layers 15, 17, 19 will increase the water resistance or water repellency properties in the construction panel 10. However, the binder is also the most expensive component of the mixture, so an amount as defined above provides a beneficial balance between effect and cost.

[00148] The back side layer 15 may also include a hydrophobic agent, such as wax. The back side layer 15 may comprise 1-3% or 1-2% of the hydrophobic agent. Preferred hydrophobic agents are paraffin emulsions. An advantage of having a hydrophobic agent in layers 15, 17, 19 of the construction panel 10 is that it provides layers 15, 17, 19 with improved water-repellent properties, in turn creating a more water-resistant construction panel 10. It can thus be beneficial to have a hydrophobic agent in layers 15, 17, 19, in which features to increase the water resistance properties in the construction panel 10 are created. Examples of this will be described later.

[00149] The back side layer 15 may also comprise different types of additives, such as dye, catalyst (e.g., ammonium sulfate), formaldehyde scavenger (e.g., urea) or buffer solution.

[00150] As described above, the intermediate layer 17 is made from the second mixture 13b, thus, the intermediate layer 17 includes at least lignocellulosic particles 17a and the binder 17b. Petition 870250085634, dated 09 / 22 / 2025, p. 46 / 117 39 / 84

[00151] The lignocellulosic particles 17a in the intermediate layer 17 may be wood particles, for example, made of pine, oak, eucalyptus or other wood species, cereal straw, sisal, coconut, bamboo, hemp, flax, jute, curauá, ramie or any combination of such particles. The lignocellulosic particles 17a constitute between 70% and 99%, above 75% or above 85% of the intermediate layer 17.

[00152] Most, that is, at least 50%, of the lignocellulosic particles 17a in the intermediate layer 17 have a particle size between 0.5 mm and 4 mm, or between 0.5 mm and 2.5 mm, or between 0.5 mm and 1.5 mm, or between 0.6 mm and 1.3 mm. Preferably, at least 60%, at least 70% or at least 80% of the lignocellulosic particles 17a in the intermediate layer 17 have a particle size between 0.5 mm and 4 mm, or between 0.5 mm and 2.5 mm, or between 0.5 mm and 1.5 mm, or between 0.6 mm and 1.3 mm. The lignocellulosic particles 17a in the intermediate layer 17 can, as explained for the back side layer 15, also be measured by an aspect ratio, that is, the ratio between the particle length and its width. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles 17a in the intermediate layer 17 is less than 30 or less than 10.Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles 17a in the intermediate layer 17 have an aspect ratio of less than 30. The aspect ratio of the majority, that is, at least 50%, of the lignocellulosic particles 17a in the intermediate layer 17 is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. Preferably, the aspect ratio of at least 60%, at least 70%, or at least 75% of the lignocellulosic particles 17a in the intermediate layer 17 is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1. At least 50% of the lignocellulosic particles 17a in the intermediate layer 17 have a particle size between... Petition 870250085634, dated 09 / 22 / 2025, p. 47 / 117 40 / 84 0.6 mm and 1.3 mm and an aspect ratio of less than 30 or less than 20. In one embodiment, the particle size of the lignocellulosic particles 17a in the intermediate layer 17 is between 0.6 mm and 1.3 mm and with an aspect ratio of less than 10. In another embodiment, the particle size of the lignocellulosic particles in the second mixture 13b is between 0.6 mm and 4 mm and with an aspect ratio of less than 20 or less than 10.

[00153] The binder 17b in the intermediate layer 17 may be a thermosetting resin. Examples of suitable thermosetting resins are amino resins, such as melamine formaldehyde, urea formaldehyde, phenol formaldehyde resins or combinations thereof, or resins without added formaldehyde, such as epoxy resins, acrylic resins, polyurethane resins, diphenylmethane diisocyanate polymer resin, polyester resins or combinations thereof. The binder 17b in the intermediate layer 17 may be the same binder as in the back side layer 15.

[00154] Binder 17b constitutes between 3% and 20%, between 3% and 12%, or between 5% and 10% of intermediate layer 17. The amount of binder 17b in intermediate layer 17, or in any of layers 15, 19 of this description, may affect the water resistance or water repellency properties of layers 15, 17, 19 of the building panel. Having more binder in layers 15, 17, 19 will increase the water resistance or water repellency properties in the building panel 10. However, the binder is also the most expensive component of the mixture, therefore, an amount such as defined above provides a beneficial balance between effect and cost. In one embodiment, the binder content in intermediate layer 17 is less than the binder content in the front side layer 19 and / or the back side layer 15.

[00155] Intermediate layer 17 may also include an agent Petition 870250085634, dated 09 / 22 / 2025, p. 48 / 117 41 / 84 hydrophobic, such as wax. The intermediate layer 17 may comprise 1-3% or 1-2% of the hydrophobic agent. Preferred hydrophobic agents are paraffin emulsions. An advantage of having a hydrophobic agent in layers 15, 17, 19 of the construction panel 10 is that it provides layers 15, 17, 19 with improved water-repellent properties, in turn creating a more water-resistant construction panel 10. It can thus be beneficial to have a hydrophobic agent in layers 15, 17, 19, in which features to increase the water resistance properties in the construction panel 10 are created. Examples of this will be described later.

[00156] The intermediate layer 17 may also comprise different types of additives, such as dye, catalyst (e.g., ammonium sulfate), formaldehyde scavenger (e.g., urea) or buffer solution.

[00157] The frontal layer 19 includes at least lignocellulosic particles 19a and binder 19b. The lignocellulosic particles 19a in the frontal layer 19 may be wood particles, for example, made of pine, oak, eucalyptus or other wood species, cereal straws, sisal, coconut, bamboo, hemp, flax, jute, curauá, ramie or any combination of such particles. The lignocellulosic particles 19a constitute between 70% and 99%, above 75% or above 85% of the frontal layer 19.

[00158] Most, i.e., at least 50%, of the lignocellulosic particles 19a in the leading-side layer 19 have a particle length between 0.3 mm and 0.6 mm. Preferably, at least 60%, at least 70%, or at least 80% of the lignocellulosic particles in the leading-side layer 19 have a particle length between 0.3 mm and 0.6 mm. In an alternative embodiment, most, i.e., at least 50%, of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm. Preferably, Petition 870250085634, dated 09 / 22 / 2025, page 49 / 117 42 / 84 at least 60%, at least 70% or at least 80% of the lignocellulosic particles in the first mixture 13a have a particle size between 0.3 mm and 1.25 mm.

[00159] The lignocellulosic particles 19a in the leading-side layer 19 can, as explained above, also be measured by an aspect ratio, that is, the ratio between the particle length and its width. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles 19a in the leading-side layer 19 is less than 30. Preferably, at least 60%, at least 70% or at least 80% of the lignocellulosic particles 19a in the leading-side layer 19 have an aspect ratio less than 30. The aspect ratio of most, that is, at least 50%, of the lignocellulosic particles 19a in the leading-side layer 19 is between 1:1 and 30:1, between 1:1 and 20:1 or between 1:1 and 10:1. Preferably, the aspect ratio of at least 60%, at least 70%, or at least 75% of the lignocellulosic particles 19a in the leading-side layer 19 is between 1:1 and 30:1, between 1:1 and 20:1, or between 1:1 and 10:1.At least 50% of the lignocellulosic particles 19a in the leading side layer 19 have a particle size between 0.3 mm and 1.25 mm, or between 0.3 mm and 0.6 mm, and an aspect ratio of less than 30 or less than 20. In one embodiment, the particle size of the lignocellulosic particles 19a in the leading side layer 19 is between 0.3 mm and 1.25 mm, or between 0.3 mm and 0.6 mm, and with an aspect ratio of less than 10.

[00160] The binder 19b in the front-side layer 19 may be a thermosetting resin. Examples of suitable thermosetting resins are amino resins, such as melamine formaldehyde, urea formaldehyde, phenol formaldehyde resins or combinations thereof, or resins without added formaldehyde, such as epoxy resins, acrylic resins, polyurethane resins, diphenylmethane diisocyanate polymer resin, polyester resins or combinations thereof. The li Petition 870250085634, dated 09 / 22 / 2025, p. 50 / 117 43 / 84 gante 19b in the front side layer 19 may be the same binder as in the first back side layer 15 and / or the intermediate layer 17.

[00161] Binder 19b constitutes between 3% and 35%, or between 10% and 25% of the front side layer 19. The amount of binder 19b in the front side layer 19, or in any of the layers 15, 17 of this description, may affect the water resistance or water repellency properties of layers 15, 17, 19. Having more binder in layers 15, 17, 19 will increase the water resistance or water repellency properties in the building panel 10. However, the binder is also the most expensive component of the mixture, thus, an amount as defined above provides a beneficial balance between effect and cost.

[00162] The front side layer 19 may also include a hydrophobic agent, such as wax. The front side layer 19 may comprise 1-3% or 1-2% of the hydrophobic agent. Preferred hydrophobic agents are paraffin emulsions. An advantage of having a hydrophobic agent in layers 15, 17, 19 of the construction panel 10 is that it provides layers 15, 17, 19 with improved water-repellent properties, in turn creating a more water-resistant construction panel 10. It can thus be beneficial to have a hydrophobic agent in layer 15, 17, 19, in which features to increase the water resistance properties in the construction panel 10 are created. Examples of this will be described later.

[00163] The front side layer 19 may also include dye 19c. Dye 19c may be a pigment, dye, or a chemical coloring agent. An example of a chemical coloring agent is ferric vitriol. By having dye 19c in the third mixture 13c, it is possible to control and adapt the appearance characteristics of the building panel 10. For example, if the front side layer 19 is the su Petition 870250085634, dated 09 / 22 / 2025, page 51 / 117 44 / 84 top surface of the construction panel 10, as illustrated in Figure 7, or if a front side element 21, such as a front side wood veneer element, or the top surface, has open features 22, as illustrated in Figure 10 and explained in more detail above and below.

[00164] The front side layer 19 may also comprise other types of additives, such as catalyst (e.g., ammonium sulfate), formaldehyde scavenger (e.g., urea) or buffer solution.

[00165] In one embodiment, the front side layer 19 may comprise wear-resistant particles, such as aluminum oxide particles or scratch-resistant particles. This may be preferred if the front side layer 19 is the top layer of the construction panel 10.

[00166] In order to further enhance the water resistance properties of the construction panel 10, the density of each layer 15, 17, 19 can be adapted to the different water resistance properties designed in layers 15, 17, 19 of the construction panel 10. For example, it may be desirable, in the front side layer 19, to design water resistance characteristics of a mechanical locking device, which will be described in more detail below, and thus it may be desirable to increase the density of the front side layer 19 in order to further enhance the water resistance characteristics of such a mechanical locking device. The intermediate layer 17, however, can be designed to have no additional water resistance characteristics and therefore not require increased density.By adjusting the density of each layer, the back side layer 15, the intermediate layer 17 and the front side layer 19, it is possible to both increase the water resistance properties of the construction panel 10 where desired and decrease the risk. Petition 870250085634, dated 09 / 22 / 2025, page 52 / 117 45 / 84 of the construction panel 10 becomes very heavy. The weight of the construction panel 10 will also depend on the thickness of each of the components of the construction panel 10, but, as it is possible to control and adapt the thickness, density, lignocellulosic particle sizes, amount of binder, etc., in each of the back side layer 15, the intermediate layer 17 and the front layer 19, the weight of the construction panel 10 also becomes controllable.

[00167] A preferred density of the intermediate layer 17 is less than the density of the front side layer 19 and / or the back side layer 15. The preferred density of the intermediate layer 17 may be between 700-900 kg / m3, or approximately 800 kg / m3. A preferred density of the front side layer 19 may be between 800-1200 kg / m3, or between 900 and 1100 kg / m3. In order to balance the construction panel 10, it is preferred that the back side layer 15, even if it does not have any additional water resistance features designed in it, has the same density as the front side layer 19. Thus, the density of the back side layer 15 is substantially the same as the density of the front side layer 19. Therefore, the density of the back side layer 15 can be between 800-1200 kg / m3, or between 900-1100 kg / m3.

[00168] In other embodiments of the present description, there may be further layers (not illustrated) of the construction panel. Such layers may comprise a mixture according to any mixture described above, with at least lignocellulosic particles and a binder. If the additional layer(s) is / are also a decorative layer, the mixture may comprise a dye. The mixture may be applied in dry or wet form and, in one embodiment, may be a powder. The mixture may be applied in any of the quantities described above. In one embodiment, an additional layer may be a coating layer. In another embodiment, a Petition 870250085634, dated 09 / 22 / 2025, p. 53 / 117 46 / 84 The additional layer may comprise wear-resistant particles, such as aluminum oxide particles, or scratch-resistant particles. This may be preferred if the additional layer is a top layer of the construction panel.

[00169] The construction panel 10 may have a thickness in the direction perpendicular to the extent of the upper surface 24 between 4 mm and 15 mm, preferably approximately 10 mm.

[00170] The ratio between the thickness of the intermediate layer 17 and the total thickness of the back side layer 15 and the front side layer 19 is between 70:30 and 30:70, or between 60:40 and 40:60.

[00171] The ratio between the thickness of the front side layer 19 and the thickness of the back side layer 15 is between 40:60 and 60:40, or between 45:55 and 55:45. The ratio between the thickness of the front side layer 19 and the thickness of the back side layer 15 is approximately 50:50.

[00172] As explained above, the construction panel 10 may also include a pattern (not shown) on the top surface of the front side layer 15, or on the front side element 21, if present, which was created simultaneously with the application of pressure and heat to form the construction panel 10. The pattern may be a desirable and attractive structure, or different levels of gloss on the top surface 24.

[00173] The differences between the construction panel illustrated in Figure 7 and the construction panels illustrated in Figures 8-10 will now be discussed.

[00174] In Figure 8, the construction panel 10 still has a front-side element 21 which was applied to the front-side layer 19 after the heat and pressure application step, i.e., after the binder of the front-side layer 19 had cured. The front-side element 21 may have been applied by means of, for example, an adhesive, such as Petition 870250085634, dated 09 / 22 / 2025, p. 54 / 117 47 / 84 as glue, or similar. The front side element 21 can be chosen from a group of a wood veneer element, a paper sheet, a resin-impregnated paper sheet or an unimpregnated paper sheet, a cork element, a polymer-based sheet, a prefabricated powder-based sheet, a powder layer composed of wood fibers and binder, a sheet, such as a thermoplastic sheet, or a coating layer, such as a lacquer. In one embodiment, such a front side element 21 is configured to receive a print. Any of the aforementioned front side elements can further be combined with a suitable wear layer, such as a lacquer, an overlay sheet or any other layer comprising, for example, wear-resistant particles, such as aluminum oxide particles, and / or scratch-resistant particles.In Figure 9A, the construction panel 10 includes, at the bottom, a rear side element 11 and, at the top, a front side element 21. The front side element 21 can be chosen from the same group as the front side elements described above.

[00175] The back side element 11 can be a balance layer. The back side element 11 can be a balance layer which is chosen to match the front side element 21, that is, if the front side element 21 is a wood veneer element, the back side layer 11 can be a wood veneer element in order to create symmetry in the construction panel 10, or if the front side element 21 is a sheet of paper, the back side layer 11 can be of the same type of paper sheet for the same reason. However, it may be possible to choose a back side element 11 that does not match the front side element 21.

[00176] Between the back side layer 11 and the side element Petition 870250085634, dated 09 / 22 / 2025, page 55 / 117 48 / 84 front 21, there is the multilayer substrate 14, which includes the back side layer 15, the intermediate layer 17 and the front side layer 19. The back side layer 15 of the multilayer substrate 14 is arranged and fixed, by means of the binder 15b in the back side layer 15, to the back side layer 11. The intermediate layer 17 is arranged between the back side layer 15 and the front side layer 19. The front side layer 19 of the multilayer substrate 14 is arranged and fixed, by means of the binder 19b in the front side layer 19, to the front side element 21.

[00177] The back side layer 15 is attached to the back side element 11 by means of binder 15b, which, during the production of the construction panel 10, penetrated the back side element 11, as illustrated in Figure 9A. The same applies to the opposite side of the construction panel 10, where the front side layer 19 is attached to the front side element 21 by means of binder 19b, which, during the production of the construction panel 10, penetrated the front side element 21, as illustrated in Figure 9A. Figure 9B is a photo of a construction panel illustrated in Figure 9A.

[00178] Furthermore, as illustrated in Figure 10, the front-side layer 19 is adapted to penetrate the open features 22, if such are present in the front-side element 21, so that the front-side layer 19 at least partially fills the open features 22. The open features may be cracks, holes, pores, or the like. Therefore, it is preferred that the front-side layer 19 also include a dye 19c. The dye may be a pigment, a dye, or a chemical coloring agent. An example of a chemical coloring agent is iron vitriol. Having a dye in the front-side layer 19 makes it possible to control and adapt the appearance characteristics of the top surface 24 of the building panel 10. For example, if the front-side element 21 has ca Petition 870250085634, dated 09 / 22 / 2025, page 56 / 117 49 / 84 open features 22, such as cracks, holes or the like, the dye of the front side layer 19 is configured to color the open features 22, as the front side layer 19, or the third mixture 13c from which the front side layer 19 is made, penetrates the open features 22 and at least partially fills such open features 22 when pressure is subsequently applied. Preferably, the front side layer 19 substantially and completely fills such open features 22, as illustrated in Figures 5 and 6.

[00179] Thus, the front-side layer 19 is configured to perform at least three tasks: blend with the intermediate layer 17, at least in the boundary area 18b; attach to the front-side element 21; and fill at least partially the open features 22, if such are present in the front-side element 21 of the construction panel 10.

[00180] Figure 11 illustrates a top view of a construction panel 10, which may be, for example, a floor panel, a wall panel, a ceiling panel or similar. The construction panel 10 has an upper surface 24, which preferably is the visible surface of the construction panel in an assembled state, and a lower surface 29, which preferably is arranged parallel to and spaced by the thickness of the construction panel 10 from the upper surface 24. The lower surface 29 further faces away from the upper surface 24. The back side layer 15 or the back side element 11 may comprise the lower surface 29. The upper surface 24 may preferably be a decorative top surface, and the front side layer 19 or the front side element 21 may comprise the upper surface 24.

[00181] The construction panel still has a first edge portion 25, a second edge portion 26, a third portion of Petition 870250085634, dated 09 / 22 / 2025, p. 57 / 117 50 / 84 edge 27 and a fourth edge portion 28. The second edge portion 26 is arranged opposite the first edge portion 25 and extends in a direction parallel to the first edge portion 25. The fourth edge portion 28 is arranged opposite the third edge portion 27 and extends in a direction parallel to the third edge portion 27. In the examples illustrated, the first and second edge portions 25, 26 are the long edge portions of construction panel 10 and the third and fourth edges 27, 28 are the short edge portions of construction panel 10. Construction panel 10 is designed to be assembled with similar or substantially identical construction panels 10', 10'', as illustrated in Figures 12A and 12B.

[00182] In order to assemble similar or essentially identical construction panels 10, 10', 10'', the first edge portion 25 and the second edge portion 26 of construction panel 10 are provided with a first mechanical locking device 30a, configured so that the first edge portion 25 of a construction panel 10 is able to mechanically lock to a second edge portion 26 of an adjacent construction panel 10' and vice versa, i.e., the first and second opposite edge portions 25, 26 are designed to be compatible with each other. The first mechanical locking device 30a preferably extends along the entire length of the first and second edge portions 25, 26, respectively.Furthermore, the third edge portion 27 and the fourth edge portion 28 of the construction panel 10 are provided with a second mechanical locking device 30b, configured so that the third edge portion 27 of a construction panel 20 is able to mechanically lock to a fourth edge portion 28 of an adjacent construction panel 20'' and vice versa, i.e., the opposite third and fourth edge portions 27, 28 are designed to be compatible with each other. The second locking device. Petition 870250085634, dated 09 / 22 / 2025, page 58 / 117 Mechanical locking device 30b preferably extends along the entire length of the third and fourth edge portions 27, 28, respectively. Each mechanical locking device 30a, 30b is configured to lock the adjacent construction panels 10, 10', 10'' in a horizontal and / or vertical direction, preferably in a horizontal and vertical direction, by means of a vertical fold and / or displacement. To be further specific, the first mechanical locking device 30a, which is disposed on the first and second edge portions 25, 26 of the construction panel, is configured to lock the adjacent construction panels 10, 10', 10'' in a direction parallel to the longitudinal extension of the third and fourth edge portions 27, 28 and in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28.On the other hand, the second mechanical locking device 30b, which is arranged on the third and fourth edge portions 27, 28 of the construction panel, is configured to lock the adjacent construction panels 10, 10', 10'' in a direction parallel to the longitudinal extension of the first and second edge portions 25, 26 and in the direction perpendicular to the longitudinal extension of the first and second edge portions 25, 26. If such construction panels 10, 10', 10'' are assembled as floor panels, the parallel directions correspond to the horizontal direction and the perpendicular directions correspond to the vertical direction.

[00183] A first construction panel 10 is mounted to a second construction panel 10' by means of the first mechanical locking device 30a provided along the respective first and second edge portions 25, 26 of the respective construction panel 10, 10'. The first mechanical locking device 30a can be configured to mount and lock adjacent construction panels 10, 10' in a horizontal and vertical direction by means of a folding offset F, see Figure 12A. Petition 870250085634, dated 09 / 22 / 2025, page 59 / 117 52 / 84

[00184] When the first construction panel 10 is assembled with the second construction panel 10', the first construction panel 10 can preferably be movable in the horizontal direction, so that the first construction panel 10 is placed in the correct location to be assembled onto the third construction panel 10''.

[00185] The first construction panel 10 is then mounted onto a third construction panel 10'' by means of the second mechanical locking device 30b provided along the respective third and fourth edge portions 27, 28 of the respective construction panel 10, 10''. The second mechanical locking device 30b can be configured to mount and lock adjacent construction panels 10, 10'' in the horizontal and vertical directions by means of a vertical displacement, such as vertical folding.

[00186] In an alternative installation (not shown), the first building panel can first be mounted to the third building panel along the short side edge, and then mounted to the second building panel along the long side edge.

[00187] In the assembled position, as illustrated in Figure 12B, an upper boundary area 25b of the first edge portion 25 of the first construction panel 10 and an upper boundary area 26b of the second edge portion 26 of the second panel 10' are juxtaposed to form a joint seal JS1 between the first and second construction panels 10, 10'. Also in the assembled position, an upper boundary area 27b of the third edge portion 27 of the first construction panel 10 and an upper boundary area 28b of the fourth edge portion 28 of the third construction panel 10'' are juxtaposed to form a joint seal JS2 between the first and third construction panels 10, 10''. These two joint seals JS1, JS2 are illustrated in more detail in Figures 13A, 13B.

[00188] The detailed description of the modalities below is based Petition 870250085634, dated 09 / 22 / 2025, pp. 60 / 117 53 / 84 in the assembly illustrated in Figure 12B, that is, with a first, a second and a third construction panels 10, 10', 10''. As all construction panels 10, 10', 10'' are similar or essentially identical, all the features of the mechanical locking device are present in each construction panel 10, 10', 10''.

[00189] Figure 13A illustrates the first mechanical locking device 30a in the assembled state of two adjacent construction panels 10, 10'. Preferably, all the features of the first mechanical locking device 30a are integrally formed in the first and second edge portions 25, 26, respectively.

[00190] The first mechanical locking device 30a comprises, along the second edge portion 26, a locking strip 32. The locking strip 32 is disposed in a lower boundary area 26a of the edge portion 26, which projects outward from the lower boundary area 26a. The locking strip 32 can be configured to be angularly displaced during folding displacement.

[00191] The locking strip 32 includes, at the outermost end of the locking strip 32, a locking element 34. The locking element 34 is configured to be received in a locking groove 44 disposed in a lower boundary area 25a of the first edge portion 25 of an adjacent construction panel, by means of folding offset.

[00192] The locking strip 32 has an elongated shape, with the locking element 34 disposed at the outermost end. Between the innermost end of the locking strip 32 and the locking element 34, the locking strip 32 has an elongated body 33. The elongated body 33 has a lower surface 33a facing the lower surface 29 of the construction panel and an upper surface 33b facing in the opposite direction, that is, towards the upper surface 24 of the construction panel. The upper surface 33b is preferably Petition 870250085634, dated 09 / 22 / 2025, page 61 / 117 54 / 84 flat surface. The lower surface 33a may be level with the lower surface 29 of the construction panel.

[00193] The upper surface 33b, in the assembled position, preferably extends in the same direction as a lower surface 46a of a locking tongue 46 on the first edge portion 25 of an adjacent construction panel, pressing against the upper surface 33b. The upper surface 33b and the lower surface 46a are preferably flat. The upper surface 33b of the elongated body 33 of the locking strip 32 is configured to, in the assembled state, cooperate with and preferably at least partially be in contact with the lower surface 46a of the locking tongue 46.

[00194] The locking element 34 of the locking strip 32 includes a front locking surface 34a. The front locking surface 34a is disposed at the innermost end of the locking element 34. The upper surface 33b of the elongated body 33 merges with the front locking surface 34a of the locking element 34. The front locking surface 34a of the locking element 34 is configured to, in the assembled state, cooperate with, and preferably at least partially be in contact with, a front wall 44a of a locking groove 44 in the first edge portion 25. The front locking surface 34a of the locking element 34 and the front wall 44a of the locking groove 44 are configured to lock two adjacent construction panels in at least one direction parallel to the longitudinal extension of the third and fourth edge portions 27, 28.

[00195] The elongated body 33 can be configured to be foldable, insofar as a portion of the elongated body 33 during the installation of two 10, 10', 10'' construction panels can be pushed and moved downwards.

[00196] In order to reduce the risk of affecting the properties of the strip Petition 870250085634, dated 09 / 22 / 2025, page 62 / 117 55 / 84 locking strip 32, for example, where the elongated body 33 is supposed to flex to one degree during the assembly process, it is preferred to control and adapt in which layer 15, 17, 19 of the multilayer substrate 14 the locking strip 32 is located. It is preferred that the majority of the locking strip 32 be located in the back side layer 15 or in the intermediate layer 17. In a preferred embodiment, the majority of the locking strip 32, that is, at least 60% or at least 80% of the locking strip 32, is projected onto the back side layer 15. Of course, the position of the locking strip 32 can be adjusted and adapted to the back side layer 15, for example, due to the preferred thickness of the back side layer 15. Conversely, the thickness of the back side layer 15 can be adjusted and adapted to the position of the locking strip 32.This is one of the main advantages of the inventive concept described here: being able to adapt and control all the characteristics of the building panel without any additional pre-processing of the building panel components.

[00197] The first mechanical locking device 30a, in the second edge portion 26, still includes a tongue groove 38. The tongue groove 38 is disposed above the locking strip 32, at the innermost end of the locking strip 32, and extends into the second edge portion 26. The tongue groove 38 is configured and formed to receive a locking tongue 46 in the first edge portion 25 of the adjacent construction panel. In the assembled position, the tongue groove 38 and the locking tongue 46 are configured to cooperate and lock two adjacent construction panels in at least one direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28. The tongue groove 38 and the locking tongue 46 may also be configured to lock two adjacent construction panels in the direction to Petition 870250085634, dated 09 / 22 / 2025, page 63 / 117 56 / 84 parallel to the longitudinal extent of the third and fourth border portions 27, 28.

[00198] An upper wall 38a of the tongue groove 38 may be configured to cooperate with, and preferably be in contact with, an upper surface 46b of the locking tongue 46 in the first edge portion 25 of an adjacent construction panel. The upper wall 38a may be configured to lock the locking tongue 38 in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28.

[00199] The first mechanical locking device 30a, in the second edge portion 26, still includes a front side tongue 40. The front side tongue 40 is disposed in an upper boundary area 26b of the second edge portion 26 and extends outward, away from the second edge portion 26. The front side tongue 40 is disposed above the tongue groove 38.

[00200] The front side tongue 40 is configured and formed to be received into a front side tongue groove 48 in the first edge portion 25 of the adjacent construction panel. In the assembled position, the front side tongue 28 and the front side tongue groove 48 are configured to lock two adjacent construction panels in the perpendicular, and preferably also parallel, direction to the longitudinal extension of the third and fourth edge portions 27, 28.

[00201] An upper surface 40a, extending in a direction parallel to the longitudinal extension of the third and fourth edge portions 27, 28 of the front-side tongue 40, is configured to cooperate with, and preferably be in contact with, an upper wall 48a of the front-side tongue groove 48. The upper wall 48a of the front-side tongue groove 48 is configured to lock the front-side tongue 40 in a direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28. Petition 870250085634, dated 09 / 22 / 2025, page 64 / 117 57 / 84

[00202] It may be preferred to have a height h1 of the front side tongue 40 between 0.5 and 2.5 mm. It is preferred that the height h1 of the front side tongue 40 be greater than the height h2 of the front side tongue groove 48. The difference between the height h1 of the front side tongue 40 and the height h2 of the front side tongue groove 48 is in the range of 0.01 to 0.5 mm, preferably 0.01 to 0.25 mm, more preferably 0.01 to 0.15 mm.

[00203] When the front side tongue 40 is disposed in the front side tongue groove 48, in the mounted position, the front side tongue 40 and the front side tongue groove 48 create a watertight seal. This is advantageous, since the watertight seal prevents, for example, water or other fluids from penetrating deeper into the mechanical locking device 30a. It is especially beneficial that the upper surface 40a of the front side tongue 40 creates a watertight seal against the upper wall 48a of the front side tongue groove 48, since this is where fluids tend to spread to the rest of the mechanical locking device 30a and to the rest of the construction panel.

[00204] In order to further increase the water resistance properties, it may be desirable to design and position at least the upper surface 40a of the front-side tongue 40 in the front-side layer 19 described above, see the upper dashed lines in Figure 13A. The characteristics of the front-side layer 19, as described above, are controlled so that they contribute to the increased water resistance properties of the mechanical locking device 30a and the construction panel 10. This is achieved, for example, by means of lignocellulosic particles of higher density and smaller size than, for example, in the intermediate layer 17, a higher binder content or the addition of a hydrophobic agent in the front-side layer 19. It is clear that the position of the upper surface Petition 870250085634, dated 09 / 22 / 2025, page 65 / 117 58 / 84 40a of the front side tongue 40 can be adjusted and adapted to the front side layer 19, for example, due to a preferred thickness of the front side layer 19. Conversely, the thickness of the front side layer 19 can be adjusted and adapted to the position of the upper surface 40a of the front side tongue 40.

[00205] Alternatively, in order to further increase water resistance properties, it may be desirable to design and position the front-side tongue 40 in the intermediate layer 17 (see the upper dashed line in Figure 15A) so as to be able to achieve a controlled expansion of at least the upper surface 40a of the front-side tongue 40 when fluid penetrates the construction panel. A controlled expansion of at least the upper surface 40a can provide a watertight seal when the front-side tongue 40 is disposed in the front-side tongue groove 48 and, in turn, provides increased water resistance properties and prevents fluid from penetrating further into the construction panel.

[00206] One of the main advantages of the inventive concept of this description is the ability to adapt and control all the characteristics of the building panel without any additional pre-processing of the building panel components.

[00207] In the upper boundary area 26b of the second edge portion 26, above the front side tongue 40, a locking surface 42 is provided that extends perpendicular to the upper surface 40a of the front side tongue 40, that is, that extends in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28. In the upper boundary area 25b of the first opposite edge portion 25, an opposite locking surface 50 is provided that extends parallel to the locking surface 42 of the second edge portion 26, that is, that extends in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28. The surface Petition 870250085634, dated 09 / 22 / 2025, p. 66 / 117 The locking surface 42 of the second edge portion 26 is configured to cooperate with, and preferably be in contact with, the locking surface 50 of the first edge portion 25 in the assembled position, as illustrated in Figure 13A. Together, the locking surface 42 of the second edge portion 26 and the locking surface 50 of the first edge portion 25 form the JS1 joint seal. The seal between the two locking surfaces 42 and 50 may preferably have a pre-tension, so that there is a force between the two locking surfaces 42 and 50 acting towards each other. This pre-tension can further reduce the risk of fluids entering the mechanical locking device 30a.

[00208] Although many of the features of the first mechanical locking device 30a on the first edge portion 25 have been described above, additional features are now described in more detail.

[00209] The first mechanical locking device 30a in the first edge portion 25 includes the locking groove 44. The locking groove 44 is disposed in the lower boundary area 25a of the first edge portion 25 and extends in an upward direction inward and away from the lower surface 29 of the construction panel.

[00210] The locking groove 44 is configured and formed to receive the locking element 34 of the locking strip 32 of the adjacent construction panel. In the assembled position, the locking groove 44 and the locking element 34 are configured to lock two adjacent construction panels in at least the direction parallel to the longitudinal extension of the third and fourth edge portions 27, 28. In order to do this, the locking groove 44, in the illustrated embodiments, includes a front wall 44a. The front wall 44a is configured to, in the assembled position, cooperate with and, preferably, at least partially be in contact with the locking surface. Petition 870250085634, dated 09 / 22 / 2025, page 67 / 117 60 / 84 to frontal 34a of the locking element 34 of the adjacent construction panel.

[00211] Furthermore, the first mechanical locking device 30a on the first edge portion 25 includes a locking tongue 46. The locking tongue 46 extends outwards, in a direction parallel to the longitudinal extension of the third and fourth edge portions 27, 28, away from the first edge portion 25.

[00212] The locking tongue 46 is at least partially configured and formed to be received in the tongue groove 38 in the second edge portion 26 of the adjacent construction panel, as explained above.

[00213] The locking tongue 46 preferably has an elongated shape, wherein at least one outermost portion 46c is received in the tongue groove 38, in the mounted position. The locking tongue 46 and the outermost portion 46c have an upper surface 46b which is configured to cooperate and preferably be in contact with the upper wall 38a of the tongue groove 38 of the adjacent construction panel. The upper wall 38a and the upper surface 46b are configured to lock two adjacent construction panels in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28.

[00214] As briefly described above, the locking tongue 46 still has a lower surface 46a. The lower surface 46a can be configured to cooperate with, and even be in contact with, the upper surface 33a of the elongated body 33 of the locking strip 32, in the assembled state. For example, during installation, the lower surface 46a can be configured to displace, and preferably push, the upper surface 33a of the elongated body 33 of the locking strip 32. As explained above, the locking strip can be flexible, allowing the lower surface 46a of the locking tongue to be flexible. Petition 870250085634, dated 09 / 22 / 2025, page 68 / 117 61 / 84 to 46 push the locking strip 32 down. This movement can increase the preferred pretension on the two parallel locking surfaces 42, 50 in the upper boundary area 25b, 26b of the respective first and second edge portions 25, 26 of adjacent building panels.

[00215] The first mechanical locking device 30a in the first edge portion 25 may also include a front side tongue groove 48. The front side tongue groove 48 is disposed above the locking tongue 46 and extends inward into the construction panel.

[00216] The front side tongue groove 48 is configured and formed to receive the front side tongue 40 in the second edge portion 26 of the adjacent construction panel. In the assembled position, the front side tongue groove 48 and the front side tongue 40 are configured to lock two adjacent construction panels in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28.

[00217] As explained above, in order to create a tight seal, it may be preferable to have a height h1 of the front side tongue 40 between 0.5 and 2.5 mm. It is preferred that the height h1 of the front side tongue 40 be greater than the height h2 of the front side tongue groove 48. Thus, as the front side tongue 40 is disposed in the front side tongue groove 48, in the mounted position, the front side tongue 40 and the front side tongue groove 48 create a tight seal. This is advantageous, since the tight seal prevents, for example, water or other fluids from penetrating deeper into the mechanical locking device 30a.

[00218] Thus, when the front side tongue 40 is disposed in the front side tongue groove 48, in the assembled position, the front side tongue 40 and the front side tongue groove 48 cri Petition 870250085634, dated 09 / 22 / 2025, page 69 / 117 62 / 84 am a watertight seal. This is advantageous, since the watertight seal prevents, for example, water or other fluids from penetrating deeper into the mechanical locking device 30a. It is especially beneficial if the upper surface 40a of the front side tongue 40 creates a watertight seal against the upper wall 48a of the front side tongue groove 48, since this is where fluids tend to spread to the rest of the mechanical locking device 30a and to the rest of the construction panel.

[00219] In the upper boundary area 25b of the first edge portion 25, above the front-side tongue groove 48, a locking surface 50 is provided that extends perpendicular to the upper wall 48a of the front-side tongue groove 48, that is, it extends in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28. In the upper boundary area 26b of the second opposite edge portion 26, the opposite locking surface 42 is provided that extends parallel to the locking surface 50 of the first edge portion 25, that is, it extends in the direction perpendicular to the longitudinal extension of the third and fourth edge portions 27, 28. The locking surface 50 of the first edge portion 25 is configured to cooperate with, and preferably be in contact with, the locking surface 42 of the second edge portion 26. in the assembled position, as illustrated in Figure 13A.Together, the locking surface 50 of the first edge portion 25 and the locking surface 42 of the second edge portion 26 form the JS1 joint seal. The seal between the two locking surfaces 42, 50 may preferably have a pre-tension, so that there is a force between the two locking surfaces 42, 50 acting towards each other. This pre-tension can further reduce the risk of fluids entering the mechanical locking device 30a. Such pre-tension between the two locking surfaces 42, 50 may, in an environment with... Petition 870250085634, dated 09 / 22 / 2025, pp. 70 / 117 63 / 84 normal humidity of two building panels, each 100 mm long, will be between 2-100 N or between 5-80 N.

[00220] Figure 13B illustrates the second mechanical locking device 30b in the assembled state. Preferably, all features, with the exception of a movable locking tongue 72, of the second mechanical locking device 30b, are integrally formed in the third and fourth edge portions 27, 28, respectively. Very similar to the first mechanical locking device 30a and its embodiments. The second mechanical locking device 30b is configured to assemble and lock adjacent building panels 10, 10', 10'' in a direction parallel and perpendicular to the longitudinal extension of the first and second edge portions 25, 26 of the building panel, by means of vertical displacement.

[00221] The second mechanical locking device 30b includes, along the fourth edge portion 28, a locking strip 52, preferably integrally formed in the fourth edge portion 28. The locking strip 52 is disposed in a lower boundary area 28a of the fourth edge portion 28, which projects outward from the lower boundary area 28a. The locking strip 52 may be configured to be angularly offset during vertical displacement.

[00222] The locking strip 52 includes, at the outermost end of the locking strip 52, a locking element 54. The locking element 54 is configured to be received in a locking groove 64 disposed in a lower boundary area 27a of the third edge portion 27 of an adjacent construction panel, by means of vertical offset.

[00223] The locking strip 52 has an elongated shape, with the locking element 54 disposed at the outermost end. Between the innermost end of the locking strip 52 and the locking element 54, the locking strip 52 has an elongated body 53. Petition 870250085634, dated 09 / 22 / 2025, pp. 71 / 117 64 / 84 The elongated body 53 has a lower surface 53a facing the lower surface 29 of the construction panel and an upper surface 53b facing in the opposite direction, that is, towards the upper surface 24 of the construction panel.

[00224] The upper surface 53b, in the assembled position, preferably extends in the same direction as a lower surface 66 in the lower boundary area 27a of the third edge portion 27 of an adjacent construction panel, pressing against the upper surface 53b. The upper surface 53b and the lower surface 66 are preferably flat. The upper surface 53b of the elongated body 53 of the locking strip 52 is configured to, in the assembled state, cooperate and preferably at least partially be in contact with the lower surface 66 in the lower boundary area 27a of the third edge portion 27.

[00225] The locking element 54 of the locking strip 52 includes a front locking surface 54a. The front locking surface 54a is disposed at the innermost end of the locking element 54. The upper surface 53b of the elongated body 53 merges with the front locking surface 54a of the locking element 54. The front locking surface 56 of the locking element 54 is configured to, in the assembled state, cooperate and preferably at least partially be in contact with a front wall 64a of a locking groove 64 in the third edge portion 27. The front locking surface 54a of the locking element 54 and the front wall 64a of the locking groove 64 are configured to lock two adjacent construction panels in at least one direction parallel to the longitudinal extension of the first and second edge portions 25, 26.

[00226] The elongated body 53 can be configured to be foldable, so that a portion of the elongated body 53, during installation Petition 870250085634, dated 09 / 22 / 2025, page 72 / 117 65 / 84 connection of two 10, 10'' construction panels, can be pushed and moved downwards.

[00227] In order to reduce the risk of affecting the properties of the locking strip 52, for example, that the elongated body 53 is supposed to flex to a degree during the assembly process, it is preferred to control and adapt in which layer 15, 17, 19 of the multilayer substrate 14 the locking strip 52 is located. It is preferred that the majority of the locking strip 52 be located in the back side layer 15 or in the intermediate layer 17. In a preferred embodiment, the majority of the locking strip 52, that is, at least 60% or at least 80% of the locking strip 52, is projected onto the back side layer 15. Of course, the position of the locking strip 52 can be adjusted and adapted to the back side layer 15, for example, due to a preferred thickness of the back side layer 15. Conversely, the thickness of the back side layer 15 can be adjusted and adapted to the position of the locking strip 52.This is one of the main advantages of the inventive concept described here: being able to adapt and control all the characteristics of the building panel without any additional pre-processing of the building panel components.

[00228] The second mechanical locking device 30b, in the fourth edge portion 28, further includes a movable tongue groove 58. The movable tongue groove 58 is disposed above the locking strip 52, at the innermost end of the locking strip 52, and extends inward, preferably inclined, into the fourth edge portion 27.

[00229] The movable tongue groove 58 is configured and formed to receive a movable locking tongue 72. The movable locking tongue 72, when disposed in the movable tongue groove 58, is configured to lock two construction panels. Petition 870250085634, dated 09 / 22 / 2025, page 73 / 117 66 / 84 adjacent in at least one direction perpendicular to the longitudinal extension of the first and second edge portions 25, 26, when coupled with a movable tongue groove 68 in the third edge portion 27 of the adjacent construction panel.

[00230] The movable locking tongue 72 can be a separate element and comprise the same material or a different material from the building panel. The movable locking tongue 72 can be made of a polymer-based material. The movable locking tongue 72 is described below in more detail with reference to Figure 14.

[00231] The first mechanical locking device 30b, in the fourth edge portion 28, still includes a front side tongue 60. The front side tongue 60 is disposed in the upper boundary area 28b of the fourth edge portion 28 and extends outward, away from the fourth edge portion 28. The front side tongue 60 is disposed above the movable tongue groove 58.

[00232] The front-side tongue 60 has an upper surface 60a which is configured to cooperate with, and preferably be in contact with, a lower surface 67 disposed in the upper boundary area 27b of the third edge portion 27 of the adjacent construction panel. The lower surface 67 of the third edge portion 27 is configured to lock the upper surface 60a of the front-side tongue 60 in the direction perpendicular to the longitudinal extension of the first and second edge portions 25 and 26.

[00233] When the upper surface 60a of the front-side tongue 60 is locked against the lower surface 67 of the third edge portion 27 of the adjacent construction panel, the upper surface 60a and the lower surface 67 create a watertight seal. This is advantageous because the watertight seal prevents, for example, water or other fluids from penetrating deeper into the locking device. Petition 870250085634, dated 09 / 22 / 2025, page 74 / 117 67 / 84 cânico 30a.

[00234] In order to further increase the water resistance properties, it may be desirable to design and position at least the upper surface 60a of the front-side tongue 60 in the front-side layer 19 described above (see the upper dashed line in Figure 13B). The characteristics of the front-side layer 19, as described above, are controlled so that they contribute to the increased water resistance properties of the mechanical locking device 30b and the construction panel 10. This is achieved, for example, by having a higher density, smaller lignocellulosic particles than, for example, in the intermediate layer 17, a higher binder content, or the addition of a hydrophobic agent in the front-side layer 19. Of course, the position of the upper surface 60a of the front-side tongue 60 can be adjusted and adapted to the front-side layer 19, for example, due to a preferred thickness of the front-side layer 19.Conversely, the thickness of the front side layer 19 can be adjusted and adapted to the position of the upper surface 60a of the front side tongue 60.

[00235] Alternatively, in order to further increase water resistance properties, it may be desirable to design and position the front-side tongue 60 in the intermediate layer 17, see the upper dashed lines in Figure 15B, so as to be able to achieve a controlled expansion of at least the upper surface 60a of the front-side tongue 60 when fluid penetrates the construction panel. A controlled expansion of at least the upper surface 60a can provide a watertight seal of the front-side tongue 60 against the lower surface 67 and, in turn, provide increased water resistance properties and prevent fluid from penetrating further into the construction panel.

[00236] One of the main advantages of this inventive concept Petition 870250085634, dated 09 / 22 / 2025, pp. 75 / 117 68 / 84 description is to be able to adapt and control all the characteristics of the building panel without any additional pre-processing of the building panel components.

[00237] In the upper boundary area 28b of the fourth edge portion 28, above the upper surface 60a of the front-side tongue 60, a locking surface 62 is provided that extends perpendicular to the upper surface 60a of the front-side tongue 60, that is, that extends in the direction perpendicular to the longitudinal extent of the first and second edge portions 25, 26. In the upper boundary area 27b of the third opposite edge portion 27 of the adjacent construction panel 1, an opposite locking surface 70 is provided that extends parallel to the locking surface 62 of the fourth edge portion 28, that is, that extends in the direction perpendicular to the longitudinal extent of the first and second edge portions 25, 26. The locking surface 62 of the fourth edge portion 28 is configured to cooperate with, and preferably be in contact with, the surface of locking 70 of the third edge portion 27, in the assembled position, as illustrated in Figure 13.Together, the locking surface 62 of the fourth edge portion 28 and the locking surface 70 of the third edge portion 27 form the JS2 joint seal. The seal between the two locking surfaces 62, 70 may preferably have a pre-tension, so that there is a force between the two locking surfaces 62, 70 acting towards each other. This pre-tension may further reduce the risk of fluids entering the mechanical locking device 30b.

[00238] Although many of the features of the second mechanical locking device 30b on the third edge portion 27 have been described above, additional features are now described in more detail.

[00239] The second mechanical locking device 30b in the ter Petition 870250085634, dated 09 / 22 / 2025, pp. 76 / 117 69 / 84 The third edge portion 27 includes the locking groove 64. The locking groove 64 is located in the lower boundary area 27a of the third edge portion 27 and extends in an upward direction inward and away from the lower surface 29 of the construction panel.

[00240] The locking groove 64 is configured and formed to receive the locking element 54 of the locking strip 52 of the adjacent construction panel. In the assembled position, the locking groove 64 and the locking element 54 are configured to lock two adjacent construction panels in at least the direction parallel to the longitudinal extension of the first and second edge portions 25, 26. In order to do this, the locking groove 64, in the illustrated embodiments, includes a front wall 64a. The front wall 64a is configured to, in the assembled position, cooperate with and preferably at least partially be in contact with the front locking surface 54a of the locking element 54 of the adjacent construction panel.

[00241] The second mechanical locking device 30b on the third edge portion 27 preferably still has the lower surface 66, as mentioned above. The lower surface 66 is disposed in the lower boundary area 27a of the third edge portion 27 of the construction panel. The lower surface 66 can be configured to cooperate and even be in contact with the upper surface 53b of the elongated body 53 of the locking strip 52, in the assembled state. For example, during installation, the lower surface 66 can be configured to displace, and preferably push, the upper surface 53a of the elongated body 53. As explained above, the locking strip can be flexible, allowing the lower surface 66 to push the locking strip 52 downwards. This movement can increase the preferred pre-tension on the two parallel locking surfaces 62, 70 in the upper boundary area 27b, 28b of the respective third and fourth Petition 870250085634, dated 09 / 22 / 2025, pp. 77 / 117 70 / 84 edge portions 27, 28 of adjacent building panels.

[00242] The second mechanical locking device 30b on the third edge portion 27 is also provided with a movable tongue groove 68. The movable tongue groove 68 is disposed below the lower surface 67 of the upper boundary area 27b and above the lower surface 66 of the lower boundary area 27a. The movable tongue groove 68 is formed and configured to receive the movable locking tongue 72, explained in more detail below. The movable tongue groove 68 extends along the longitudinal extent of the third edge portion 27 of the construction panel.

[00243] The movable tongue groove 68 is configured to, together with the movable locking tongue 72, lock two adjacent construction panels in the direction perpendicular to the longitudinal extension of the first and second edge portions 25, 26.

[00244] Above the movable tongue groove 68, the lower surface 67 of the upper boundary area 27b of the third edge portion 27 is provided. The lower surface 67 extends in a direction parallel to the longitudinal extension of the first and second edge portions 25, 26. The lower surface 67 faces downwards towards the lower surface 29 of the construction panel. The lower surface 67 is configured to, in the direction perpendicular to the longitudinal extension of the first and second edge portions 25, 26, lock the upper surface 60a of the front side tongue 60 in the mounted position. The lower surface 67 is configured to cooperate with, and preferably be in contact with, the upper surface 60a of the front side tongue 60 in the mounted position.

[00245] In the upper boundary area 27b of the third edge portion 27, above the lower surface 67, a locking surface 70 is provided that extends perpendicular to the lower surface 67, that is, extending in the direction perpendicular to the longitudinal extent of Petition 870250085634, dated 09 / 22 / 2025, pp. 78 / 117 71 / 84 first and second edge portions 25, 26. In the upper boundary area 28b of the fourth opposite edge portion 28, the opposite locking surface 62 is provided, which extends parallel to the locking surface 70 of the third edge portion 27, that is, extending in the direction perpendicular to the longitudinal extent of the first and second edge portions 25, 26. The locking surface 70 of the third edge portion 27 is configured to cooperate with, and preferably be in contact with, the locking surface 62 of the fourth edge portion 28, in the assembled position, as illustrated in Figure 13B. Together, the locking surface 70 of the third edge portion 27 and the locking surface 62 of the fourth edge portion 28 form the joint seal JS2. The seal between the two locking surfaces 62 and 70 may preferably have a pre-tension, so that there is a force between the two locking surfaces 62 and 70 acting towards each other.This pre-tension can further reduce the risk of fluids entering the mechanical locking device 30b. Such pre-tension between the two locking surfaces 62 and 70 can, in a normal humidity environment of two building panels, each 100 mm long, be between 2-100 N or between 5-80 N.

[00246] Illustrated in Figure 14, the movable locking tongue 72 has a longitudinal base portion 74 which extends continuously along the length of the movable locking tongue 72. Along the base portion 74, several elongated flexible or foldable parts 76 are provided. The elongated foldable parts 76 are integrally formed with the base portion 74 at a first end 77a. The opposite second end 77b of the foldable part 76 is configured to move freely between a rest position and a mounted position.

[00247] In the resting position, as illustrated in Figure 14, the Petition 870250085634, dated 09 / 22 / 2025, p. 79 / 117 72 / 84 elongated folding parts 76 extend away from the base portion 74, with the second end 77b furthest from the base portion 74. Between the elongated folding part 76 and the base portion 74, a slot, or gap 78, is provided in the resting position. The folding part 76 can be folded down into the slot 78 towards the base portion 74. In an assembled position, the folding parts 76 are folded into the slot 78.

[00248] The movable locking tongue 72 is configured to be received in the movable tongue slot 58 on the fourth edge portion 28 and in the movable tongue slot 68 on the third edge portion 27, as illustrated in Figure 13B.

[00249] Before assembling the adjacent construction panels 10, 10'', the movable locking tongue 72 is disposed in the movable tongue groove 58 on the fourth edge portion 28, with the folding parts 76 facing the movable tongue groove 58 and the longitudinal base portion 74 disposed just outside the movable tongue groove 58, facing the construction panel to be assembled.

[00250] During installation, construction panel 10 is vertically pushed down into the adjacent construction panel 10'', where construction panel 10 pushes the base portion 74, forcing the folding parts 76 to be displaced into the slot 78 towards the base portion 74, allowing construction panel 10 to continue descending. When construction panel 10 is in the assembled position, the longitudinal base portion 74 of the displaceable locking tongue 72 engages with the displaceable tongue groove 68 of the third edge portion 27, locking the two construction panels 10, 10'', in the horizontal and vertical directions. EXAMPLES Example 1: 10 mm construction panel

[00251] In Example 1, a three-layer construction panel Petition 870250085634, dated 09 / 22 / 2025, pp. 80 / 117 73 / 84 of 10 mm was pressed in a single-opening laboratory press (500 x 500 mm) at 180°C with a pressing time factor of 12 s / mm. The construction panel was manufactured by applying 20% ​​by weight of the first mixture, or approximately 1.9 kg / m2, forming the back side layer, 60% by weight of the second mixture, or approximately 5.6 kg / m2, forming the middle layer, and 20% by weight of the third mixture, forming the front side layer, or approximately 1.9 kg / m2. The second mixture comprised wood particles (mixture of 70% oak and 30% fir, in the size of 0.6-1.25 mm) which were mixed with 10% MUF resin and 1.5% hydrophobic agent (paraffin emulsion). The first and third mixtures both comprised wood particles (a mixture of 70% oak and 30% fir, with a size of 0.315-0.6 mm) which were mixed with 20% MUF resin and 1.5% hydrophobic agent (paraffin emulsion).Note: As is common in the timber industry, quantities are calculated by dry weight, with the quantity of dry wood = 100% as the base.

[00252] The resulting construction panel had a density of 940 kg / m3 (EN 323), compared with a standard P5 type particleboard (according to EN 312) with a density of 655 kg / m3 and a floor-quality HDF board with a density of 940 kg / m3. A construction panel produced according to Example 1 had a density profile (Figure 17) closer to a standard HDF board (Figure 21) than to a standard moisture-resistant, load-bearing P5 type particleboard (Figure 20).

[00253] The resulting construction panel exhibited an internal bond strength of 2.34 N / mm2 (EN 319) and a thickness expansion of 2.2% (EN 317). The internal bond strength of the store-bought P5 type particleboard was 0.55 NW and its thickness expansion was 2.2% (EN 317). Petition 870250085634, dated 09 / 22 / 2025, pp. 81 / 117 The sura of the 74 / 84 sample was 7.6%. For the HDF board, the internal bond strength was 1.95 N / mm² and its thickness expansion was 10.2%. After the thickness expansion test, all samples were dried until completely dry, and the thickness was measured on the dried samples. The thickness of the construction panel of this sample was initially thinner (1.88%), while the HDF board remained thicker than initially (+0.79%), and the standard P5 type particle board fell between the two (-0.62%). This indicates irreversible damage to the HDF caused by immersion in water, while the construction panel and particle board were not irreversibly damaged. This can also be seen visually with raised edges, while no raised edges were seen on the construction panel of this example. Example 2: Different Particle Sizes

[00254] In Example 2, a three-layer 10 mm construction panel was pressed in a single-opening laboratory press (500 x 500 mm) at 160°C with a pressing time factor of 12 s / mm. The construction panel was manufactured by applying 20% ​​by weight of the first mixture, or approximately 1.9 kg / m2, forming the back side layer, 60% by weight of the second mixture, or approximately 5.6 kg / m2, forming the middle layer, and 20% by weight, or approximately 1.9 kg / m2, of the third mixture, forming the front side layer. For the second mixture, wood particles were mixed with 12% MUF resin and 2.0% hydrophobic agent (paraffin emulsion). For both the first and third mixtures, wood particles were mixed with 20% MUF resin and 1.5% hydrophobic agent (paraffin emulsion).The wood particles used were a mixture of 70% oak, 20% fir, and 10% of a mixture of species classified for cellulose. In the first series, the particle size of the particles in the second mixture was 2.5-4.0 mm, and in the first and third mixtures... Petition 870250085634, dated 09 / 22 / 2025, page 82 / 117 75 / 84 of 0.3-1.25 mm, resulting in a construction panel with a density of 916 kg / m3. In a second series, the particle size in the second layer was 0.6-1.25 mm and in the first and third mixtures 0.3-0.6 mm, resulting in a construction panel with a density of 967 kg / m3.

[00255] This test showed that fine particles are preferable to meet high technological requirements. The building panel with fine particles, i.e., the second series, performed better than the building panel with relatively coarse particles, i.e., the first series. The internal bond strength (EN 319) for the building panel with fine particles was 3.60 N / mm2 and the surface hardness (EN 311) was 2.80 N / mm2. For the building panel with coarse particles, the internal bond strength was 2.74 N / mm2 and the surface hardness was 2.46 N / mm2. Example 3: Effect of a Hydrophobic Agent

[00256] In Example 3, a 10 mm three-layer construction panel was pressed in a single-opening laboratory press (300 x 300 mm) at 180°C with a pressing time factor of 12 s / mm at three different density levels (800 kg / mF, 900 kg / m3 and 1000 kg / m3) and five paraffin emulsion levels (1.0%, 1.3%, 1.5%, 1.7% and 2.0%). The construction panel was manufactured by applying 20% ​​by weight of the first mixture, or approximately 1.60, 1.80, 2.00 kg / m² for each density level, forming the back side layer; 60% by weight of the second mixture, or approximately 4.80, 5.40, 6.00 kg / m² for each density level, forming the middle layer; and 20% by weight of the third mixture, or approximately 1.60, 1.80, 2.00 kg / m² for each density level, forming the front side layer. For the second mixture, wood particles (mixture of 70% oak and 30% fir, with a size of 0.6-1.25 mm) were mixed with 10% MUF resin and the agent levels. Petition 870250085634, dated 09 / 22 / 2025, page 83 / 117 76 / 84 hydrophobic (paraffin emulsion) as previously mentioned. For both the first and third mixtures, wood particles (mixture of 70% oak and 30% fir, 0.2-0.6 mm in size) were mixed with 20% MUF resin and the previously mentioned levels of hydrophobic agent (paraffin emulsion), i.e., 1.0%, 1.3%, 1.5%, 1.7%, and 2.0%. The resulting building panels clearly showed a reduction in thickness expansion (EN 317) between 1.0% and 1.3% hydrophobic agent, see Figure 16. The hydrophobic agent content increased above 1.3% showed no improvement or only marginal improvement in thickness expansion. Example 4: High-Performance Building Panel

[00257] In Example 4, a three-layer 10 mm construction panel was pressed in a single-opening laboratory press (500 x 500 mm) at 160°C with a pressing time factor of 12 s / mm. The construction panel was manufactured by applying 20% ​​by weight of the first mixture, or approximately 2.0 kg / m2, forming the back side layer, 60% by weight of the second mixture, or approximately 5.5 kg / m2, forming the middle layer, and 20% by weight of the third mixture, or approximately 2.0 kg / m2, forming the front side layer. For the second mixture, wood particles (mixture of 70% oak and 30% spruce, 0.6-1.25 mm in size) were mixed with 12% MUF resin and 3.0% hydrophobic agent (paraffin emulsion). For both the first and third mixtures, wood particles (a mixture of 70% oak and 30% fir, measuring 0.315-0.6 mm) were mixed with 20% MUF resin and 2.5% hydrophobic agent (paraffin emulsion).The resulting construction panel had a density of 990 kg / m3 (EN 323). The resulting construction panel showed an internal bond strength of 3.61 N / mm2 (EN 319) and exhibited expansion. Petition 870250085634, dated 09 / 22 / 2025, p. 84 / 117 77 / 84 thickness of 2.1% (EN 317). The modulus of elasticity (EN 310) of this construction panel was 5212 MPa and the flexural strength (EN 310) was 34.4 N / mm2, which is well above what EN 312 requires for high-strength load-bearing particleboard of type P7. Example 5: 11 mm Construction Panel with Wood Veneer as the Front Side Element, Preferably Used as a Floor Panel

[00258] In Example 5, an 11 mm construction panel was pressed in a single-opening laboratory press (500 x 500 mm) at 170°C with a pressing time factor of 12 s / mm. The five-layer construction panel was manufactured by providing a balance layer of birch veneer, applying 20% ​​by weight of the first mixture, or approximately 1.7 kg / m2, forming the back side layer, 60% by weight of the second mixture, or approximately 4.9 kg / m2, forming the middle layer, 20% by weight of the third mixture, or approximately 1.7 kg / m2, forming the front side layer, and a decorative layer of oak veneer. For the second mixture, wood particles (a mixture of 70% oak, 20% fir, and 10% unknown mixture, with a size of 0.61-25 mm) were mixed with 12% MUF resin and 2.0% hydrophobic agent (paraffin emulsion).For both the first and third mixtures, wood particles (a mixture of 70% oak, 20% fir, and 10% unknown mixture, with a size of 0.3-0.6 mm) were mixed with 25% MUF resin and 1.0% hydrophobic agent (paraffin emulsion). The resulting construction panel had a density of 824 kg / m3 (EN 323), and a typical density profile is shown in Figure 19. The resulting construction panel had a surface hardness (EN 311) of 2.25 N / mm2. Example 6: 6 mm Construction Panel Petition 870250085634, dated 09 / 22 / 2025, page 85 / 117 78 / 84

[00259] In Example 6, a three-layer 6 mm construction panel was pressed in a single-opening laboratory press (500 x 500 mm) at 130°C with a pressing time factor of 20 s / mm. The construction panel was manufactured by applying approximately 4 kg / m2 of the first mixture, forming the back side layer, approximately 4 kg / m2 of the second mixture, forming the middle layer, and approximately 4 kg / m2 of the third mixture, forming the front side layer. The second mixture comprised wood particles (mixture of 70% oak, 20% spruce and 10% unknown mixture, with a size of 0.315-0.6 mm), which were mixed with 20% MUF resin and 2.0% hydrophobic agent (paraffin emulsion). Both the first and third mixtures comprised wood particles (mixture unknown, with a size of 0.05-0.3 mm), which were mixed with 145% MF resin, 15% pigments, and 30% corundum particles.The resulting construction panel had a density of 1150 kg / m3 (EN323). A typical density profile of the 6 mm construction panel is shown in Figure 18. The actual maximum density is higher than that shown, but since the actual density is outside the machine's measuring range, the tops are cut at approximately 1350 kg / m3.

[00260] Finally, although the inventive concept has been described above with reference to specific embodiments, it is not intended to be limited to the specific form set forth herein. Instead, the invention is limited only by the accompanying claims. Other embodiments beyond those specified above are equally possible within the scope of the appended claims. All embodiments can be used separately or in combination. Angles, dimensions, rounded parts, spaces between surfaces, etc., are only examples and can be adjusted within the basic principles of the invention. Petition 870250085634, dated 09 / 22 / 2025, page 86 / 117 79 / 84 ITEMS

[00261] Item 1. A method for producing a building panel (10), such as a floor panel or wall panel, comprising:

[00262] provide a back side layer (15) comprising a first mixture of at least lignocellulosic particles and a binder,

[00263] apply an intermediate layer (17) comprising a second mixture of at least lignocellulosic particles and a binder, in the back side layer (15),

[00264] apply a front side layer (19) comprising a third mixture of at least lignocellulosic particles and a binder, in the intermediate layer (17),

[00265] apply pressure and heat to form said construction panel (10), in which

[00266] the lignocellulosic particles of the second mixture and the lignocellulosic particles of the third mixture are those which are mixed, at least in a boundary area (18b) between the intermediate layer (17) and the front side layer (19),

[00267] create a mechanical locking device (30a; 30b) along at least one edge (25, 26, 27, 28) of the building panel (10), wherein the mechanical locking device (30a; 30b) is configured for horizontal and / or vertical locking of similar or essentially identical building panels (10, 10', 10'') in an assembled position, the mechanical locking device (30a; 30b) comprising

[00268] an upper surface (40a; 60a), which is disposed in a front side area (26b; 28b) of at least one edge portion (25, 26, 27, 28) which extends in a direction essentially parallel to an upper surface (24), along at least Petition 870250085634, dated 09 / 22 / 2025, p. 87 / 117 80 / 84 a portion of edge (25, 26, 27, 28) of the construction panel (10), offset from said upper surface (24), wherein the upper surface (40a; 60a) is disposed in the front side layer (19).

[00269] Item 2. The method according to item 1, wherein the mechanical locking device (30a; 30b) further comprises:

[00270] a locking strip (32; 52) with a locking element (34; 54), which is disposed in a back side area (26a; 28a) of at least one edge portion (25, 26, 27, 28) and which extends in a direction essentially parallel to a back surface (29), along at least one edge portion (25, 26, 27, 28) of the construction panel (10), wherein the locking strip (32; 52) and the locking element (34; 54) are created at least partially in the back side layer (15).

[00271] Item 3. The method according to item 2, wherein at least 60% or at least 80% of the locking strip (32; 52) and the locking element (34; 54) are created in the back side layer (15).

[00272] Item 4. The method according to any of the preceding items, wherein the front side layer (19) is the top layer comprising said top surface (24) of the construction panel (10).

[00273] Item 5. The method according to item 4, wherein the method further comprises:

[00274] create a pattern on the top surface (24) of the front side layer (19) simultaneously with the application of pressure and heat to form the building panel (10).

[00275] Item 6. The method according to any of items 13, wherein a front-side element (21) is applied to the subsequent front-side layer (19) applying pressure and heat to form said construction panel (10). Petition 870250085634, dated 09 / 22 / 2025, pp. 88 / 117 81 / 84

[00276] Item 7. The method according to any of items 13, wherein the method further comprises, before applying pressure and heat to form the construction panel:

[00277] provide a back side element (11) onto which the first mixture is applied, creating the back side layer (15), and / or

[00278] apply a front side element (21) over the front side layer (19), where

[00279] the front side layer (19) is fixed to the front side element (21) and the back side layer (15) is fixed to the back side layer (11) when pressure and heat are applied.

[00280] Item 8. The method according to item 7, wherein the rear side element (11) and / or the front side element (21) is a wood veneer element.

[00281] Item 9. The method according to item 7, wherein the back side element (11) and / or the front side element (21) is a sheet of paper, an unimpregnated sheet of paper or an impregnated sheet of paper.

[00282] Item 10. The method according to any of items 79, wherein the method further comprises:

[00283] create a pattern on an upper surface (24) of the front side element (21) simultaneously with the application of pressure and heat to form the building panel.

[00284] Item 11. The method according to any of the preceding items, wherein the third mixture further comprises a colorant, such as a pigment, dye or chemical coloring agent.

[00285] Item 12. The method according to any of the preceding items, wherein at least 50% of the lignocellulosic particles in the second mixture have an aspect ratio between 1:1 and 30:1.

[00286] Item 13. A building panel, such as a panel of Petition 870250085634, dated 09 / 22 / 2025, page 89 / 117 82 / 84 floor or wall panel, comprising

[00287] a multilayer substrate (14) comprising

[00288] a back-side layer (15) comprising lignocellulosic particles and a binder,

[00289] an intermediate layer (17) comprising lignocellulosic particles and a binder, arranged over the back side layer (15), and

[00290] a front-side layer (19) comprising lignocellulosic particles and a binder, arranged over the intermediate layer (17), wherein

[00291] the back side layer (15) was formed from a first mixture, the intermediate layer (17) was formed from a second mixture and the front side layer (19) was formed from a third mixture, wherein the lignocellulosic particles of the second mixture and the lignocellulosic particles of the third mixture are mixed, at least in a boundary area (18b) between the intermediate layer (17) and the front side layer (19),

[00292] the construction panel still comprising:

[00293] a mechanical locking device (30a; 30b) disposed along at least one edge portion (25, 26, 27, 28) of the building panel, wherein the mechanical locking device (30a; 30b) is configured for horizontal and / or vertical locking of similar or essentially identical building panels (10, 10', 10'') in an assembled position, the mechanical locking device (30a; 30b) comprising

[00294] an upper surface (40a; 60a), which is disposed in a front side area (26b; 28b) of at least one edge portion (25, 26, 27, 28) and which extends in a direction essentially parallel to an upper surface (24), along at least one edge portion (25, 26, 27, 28) of the construction panel, displaced Petition 870250085634, dated 09 / 22 / 2025, pp. 90 / 117 83 / 84 each of said upper surface (24), in which

[00295] the upper surface (40a; 60a) is further arranged in the front side layer (19) of the construction panel.

[00296] Item 14. The construction panel according to item 13, in which the mechanical locking device further comprises:

[00297] a locking strip (32; 52) with a locking element (34; 54), which is disposed in a rear side area (15) of at least one edge portion (25, 26, 27, 28) and which extends in a direction essentially parallel to a rear surface (15), along at least one edge portion (25, 26, 27, 28) of the construction panel, wherein

[00298] the locking strip (32; 52) and the locking element (34; 54) are disposed at least partially in the back side layer (15) of the construction panel.

[00299] Item 15. The construction panel according to item 14, wherein the locking strip (32; 52) and the locking element (34; 54) are arranged in the back side layer (15), such that at least 60% or at least 80% of the locking strip (32; 52) and the locking element (34; 54) are arranged in the back side layer (15).

[00300] Item 16. The construction panel according to any of items 13-15, wherein the front side layer (19) is the top layer comprising said top surface (24) of the construction panel.

[00301] Item 17. The construction panel according to any of items 13-15, wherein the construction panel further comprises:

[00302] a back side element (11) to which the back side layer (15) is attached, and / or

[00303] a front-side element (21) to which the front-side layer (19) is attached. Petition 870250085634, dated 09 / 22 / 2025, pp. 91 / 117 84 / 84

[00304] Item 18. The construction panel according to item 17, wherein the back side element (11) and / or the front side element (21) are wood veneered.

[00305] Item 19. The construction panel according to item 17, wherein the back side element (11) and / or the front side element (21) are a sheet of paper, a non-impregnated sheet of paper or an impregnated sheet of paper.

Claims

1. Method for producing a building panel (10), such as a floor panel or wall panel, the method characterized in that it comprises: providing a back-side layer (15) comprising a first mixture of at least lignocellulosic particles and a binder, applying an intermediate layer (17) comprising a second mixture of at least lignocellulosic particles and a binder to the back-side layer (15), applying a front-side layer (19) comprising a third mixture of at least lignocellulosic particles and a binder to the intermediate layer (17), wherein an average particle size in the second mixture is larger than an average particle size in the first and / or third mixtures, applying pressure and heat to form said building panel (10), creating a mechanical locking device (30a; 30b) along at least one edge (25, 26, 27, 28) of the building panel (10), wherein the mechanical locking device (30a;30b) is configured for horizontal and / or vertical locking of similar or essentially identical building panels (10, 10', 10'') in an assembled position, the mechanical locking device (30a; 30b) comprising an upper surface (40a; 60a), which is disposed in a front side area (26b; 28b) of at least one edge portion (25, 26, 27, 28) and which extends in a direction essentially parallel to an upper surface (24), along at least one edge portion (25, 26, 27, 28) of the building panel (10), Petition 870250085634, dated 22 / 09 / 2025, p. 93 / 117 2 / 6 displaced from said upper surface (24), wherein the upper surface (40a; 60a) is disposed in the front side layer (19).; 2. Method according to claim 1, characterized in that the mechanical locking device (30a; 30b) further comprises: a locking strip (32; 52) with a locking element (34; 54), which is disposed in a back side area (26a; 28a) of at least one edge portion (25, 26, 27, 28) and which extends in a direction essentially parallel to a back surface (29), along at least one edge portion (25, 26, 27, 28) of the construction panel (10), wherein the locking strip (32; 52) and the locking element (34; 54) are created at least partially in the back side layer (15).

3. Method according to claim 2, characterized in that at least 60% or at least 80% of the locking strip (32; 52) and the locking element (34; 54) are created in the back side layer (15).

4. Method, according to any of the preceding claims, characterized in that the front side layer (19) is the top layer comprising said top surface (24) of the construction panel (10).

5. Method according to claim 4, characterized in that the method further comprises: creating a pattern on the upper surface (24) of the front side layer (19) simultaneously with the application of pressure and heat to form the building panel (10).

6. Method, according to any one of claims 1 to 3, characterized in that a front-side element (21) is applied to the subsequent front-side layer (19) applying pressure and heat to form the construction panel (10). Petition 870250085634, dated 22 / 09 / 2025, p. 94 / 117 3 / 6 7. Method, according to any one of claims 1 to 3, characterized in that the method further comprises, before applying pressure and heat to form the construction panel: providing a back side element (11) onto which the first mixture is applied, creating the back side layer (15), and / or applying a front side element (21) onto the front side layer (19), wherein the front side layer (19) adheres to the front side element (21) and the back side layer (15) adheres to the back side layer (11), when pressure and heat are applied.

8. Method according to claim 7, characterized in that the rear side element (11) and / or the front side element (21) is a wood veneer element.

9. Method according to claim 7, characterized in that the back side element (11) and / or the front side element (21) are a sheet of paper, an unimpregnated sheet of paper or an impregnated sheet of paper.

10. Method, according to any one of claims 7 to 9, characterized in that the method further comprises: creating a pattern on an upper surface (24) of the front side element (21) simultaneously with the application of pressure and heat to form the building panel.

11. A method, according to any of the preceding claims, characterized in that the third mixture further comprises a dye, such as a pigment, colorant or chemical coloring agent.

12. Method, according to any of the preceding claims, characterized in that at least 50% of the lignocellulosic particles in the second mixture have an aspect ratio between 1:1 and 30:

1.

13. Method, according to any of the preceding claims, characterized in that lignocellulosic particles of the second mixture and lignocellulosic particles of the third mixture are mixed, at least in a boundary area (18b) between the intermediate layer (17) and the front side layer (19).

14. Construction panel, such as a floor panel or wall panel, the construction panel characterized in that it comprises a multilayer substrate (14) comprising a back-side layer (15) comprising lignocellulosic particles and a binder, an intermediate layer (17) comprising lignocellulosic particles and a binder, disposed over the back-side layer (15), and a front-side layer (19) comprising lignocellulosic particles and a binder, disposed over the intermediate layer (17), wherein the back-side layer (15) was formed from a first mixture, the intermediate layer (17) was formed from a second mixture and the front-side layer (19) was formed from a third mixture, wherein an average particle size in the second mixture is larger than an average particle size in the first and / or third mixtures, the construction panel further comprising: a mechanical locking device (30a;30b) arranged along at least one edge portion (25, 26, 27, 28) of the construction panel, wherein the mechanical locking device (30a; 30b) is configured for horizontal and / or vertical locking of panels Petition 870250085634, dated 09 / 22 / 2025, page. 96 / 117 5 / 6 of similar or essentially identical construction (10, 10', 10'') in an assembled position, the mechanical locking device (30a; 30b) comprising an upper surface (40a; 60a), which is disposed in a front side area (26b; 28b) of at least one edge portion (25, 26, 27, 28) and which extends in a direction essentially parallel to an upper surface (24), along at least one edge portion (25, 26, 27, 28) of the construction panel, offset from said upper surface (24), wherein the upper surface (40a; 60a) is further disposed in the front side layer (19) of the construction panel.; 15. Construction panel, according to claim 14, characterized in that the mechanical locking device further comprises: a locking strip (32; 52) with a locking element (34; 54), which is disposed in a back side area (15) of at least one edge portion (25, 26, 27, 28) and which extends in a direction essentially parallel to a back surface (15), along at least one edge portion (25, 26, 27, 28) of the construction panel, wherein the locking strip (32; 52) and the locking element (34; 54) are disposed at least partially in the back side layer (15) of the construction panel.

16. Construction panel, according to claim 15, characterized in that the locking strip (32; 52) and the locking element (34; 54) are arranged in the back side layer (15), such that at least 60% or at least 80% of the locking strip (32; 52) and the locking element (34; 54) are arranged in the back side layer (15).

17. Construction panel, according to any of claims 14 to 16, characterized in that the front side layer (19) is the top layer comprising said top surface (24) of the construction panel.

18. Construction panel, according to any one of claims 14 to 16, characterized in that the construction panel further comprises: a back side element (11) to which the back side layer (15) is attached, and / or a front side element (21) to which the front side layer (19) is attached.

19. Construction panel, according to claim 18, characterized in that the rear side element (11) and / or the front side element (21) are wood veneered.

20. Construction panel, according to claim 18, characterized in that the back side element (11) and / or the front side element (21) are a sheet of paper, an unimpregnated sheet of paper or an impregnated sheet of paper.

21. Construction panel, according to any of the preceding claims, characterized in that lignocellulosic particles of the second mixture and lignocellulosic particles of the third mixture are mixed, at least in a boundary area (18b) between the intermediate layer (17) and the front side layer (19).

Images