Panel, in particular floor panel, ceiling panel or wall panel, covering composed of a plurality of panels and method of recycling a panel

Abstract

A panel with a planar design, particularly a floor panel, ceiling panel, or wall panel, having a top side and a bottom side as well as a plurality of side edges; the panel having a structure of a plurality of laminated layers adhered to each other, wherein the plurality of laminated layers extend parallel to the plane of the panel and includes: a core layer having a lower side and an upper side; and a top layer disposed directly or indirectly on the upper side of the core layer, wherein at least two layers of the laminated structure, particularly the top layer and the core layer, are directly or indirectly adhered to each other.

Description

Technical Field

[0001] The present invention relates to a panel with a planar design, particularly a floor panel, ceiling panel, or wall panel, having a top side, a bottom side, and a plurality of side edges;

[0002] The panel has a structure with multiple laminated layers adhered to each other, wherein the multiple laminated layers extend parallel to the plane of the panel and include:

[0003] It has a core layer on a lower side and an upper side; and

[0004] The top layer is set directly or indirectly on the upper side of the core layer. Background Technology

[0005] In such panels, the core and top layers each have different functions, and therefore the basic materials used to manufacture these layers are usually different. When such panels are recycled after use to recover the basic materials used to make them, it is beneficial if the different materials from the different layers can be recycled in separate streams. The most convenient way to achieve this is to first physically separate the multiple laminated layers of the panel from each other, and then recycle the separated layers in separate batches.

[0006] However, separating or peeling the constituent layers of a panel is not a simple task because the adhesives commonly used in this field are permanent adhesives such as polyurethane adhesives, which have high adhesive strength and achieve durable bonding of the laminates, making them difficult to break. Even when the bond is broken under high forces, complete peeling—that is, peeling that perfectly separates the different layers from each other—is impossible in most cases. Therefore, due to the inherent imperfections in peeling, the recycling of panels is known to result in a contaminated stream of recycled material.

[0007] In view of the above-mentioned disadvantages, there is a general need to provide a panel that is more suitable for recycling purposes, wherein when the panel is used, the panel includes a durable adhesive laminate, and the panel also has the feature of allowing more thorough peeling of the adhesive layer for recycling purposes. Summary of the Invention

[0008] To meet the aforementioned general needs, the present invention provides, in its first aspect, the following:

[0009] A panel with a planar design is provided, particularly a floor panel, ceiling panel, or wall panel, having a top side, a bottom side, and multiple side edges;

[0010] The panel has a structure with multiple laminated layers adhered to each other, wherein the multiple laminated layers extend parallel to the plane of the panel and include:

[0011] It has a core layer on a lower side and an upper side; and

[0012] The top layer is set directly or indirectly on the upper side of the core layer;

[0013] In the laminated structure, at least two layers, particularly the top layer and the core layer, are adhered to each other directly or indirectly by a switchable adhesive with adjustable adhesive strength;

[0014] Specifically, by exposing the switchable adhesive present between the two adhesive layers to conditions that allow for adjustment of the adhesive strength from an operating value suitable for the panel during use to a reduced value suitable for the panel's recycling, wherein the conditions are:

[0015] Irradiation; and / or

[0016] Heat treatment; and / or

[0017] Solvent; and / or

[0018] pH modifier;

[0019] The reduced adhesive strength of the switchable adhesive facilitates complete peeling of the two adhesive layers.

[0020] In the context of this invention, it has been found that by exposing the switchable adhesive present between the two adhesive layers to one of the four treatments described above, the adhesive strength of the two adhesive layers at their interface can be significantly reduced. Furthermore, it has been found that the adhesive strength can be reduced to such a degree that the two adhesive layers can be peeled off without using excessive force, and thus in a thorough and near-perfect manner, ensuring that neither of the two peeled layers is contaminated by the material of the other layer. Therefore, the proposed panel is more suitable for recycling purposes because the improved peeling achievable with the switchable adhesive allows for the generation of two separate material streams from the two respective peeled layers, each possessing enhanced purity.

[0021] In this case, preferably, the reduction in adhesive strength is 60% or less of the operating value, more preferably 50% or less, and even more preferably 40% or less.

[0022] It has been found that this reduction in adhesive strength is particularly effective in allowing complete peeling of the two adhesive layers under common practical conditions.

[0023] Furthermore, the following preferred configurations of the panel according to the invention are applicable:

[0024] The planar design is rectangular or hexagonal;

[0025] The length of the panel is in the range of 0.40m to 2.0m, the width is in the range of 70mm to 180mm, and the total thickness is 2mm to 20mm, preferably 3mm to 12mm;

[0026] The thickness of the core layer is 2 mm to 7 mm, and / or the thickness of the top layer is 1 mm to 5 mm;

[0027] The switchable adhesive has the form of an adhesive layer between the two adhesive layers, which can be a continuous layer or a discontinuous layer.

[0028] Preferably, the panel is a decorative panel comprising a decorative top layer. The (decorative) top layer is preferably substantially rigid, which generally results in a substantially rigid or semi-flexible panel. The core is preferably substantially rigid, semi-flexible, or flexible. The top layer is preferably waterproof to protect the switchable adhesive and core from water applied to the upper surface of the panel (e.g., for cleaning purposes). Typically, the outer peripheral edge of the switchable adhesive layer remains exposed to the surrounding atmosphere and is not protected by the top layer. In this regard, the switchable adhesive is preferably starch-free, as starch has poor water resistance. Preferably, the switchable adhesive comprises and / or is polyurethane-based, more preferably polyurethane with an average molecular weight of 2,000 to 100,000, because polyurethane exhibits relatively good water resistance, and because the core and / or top layer increasingly consist at least partially of and / or are at least partially based on polyurethane. The latter not only aids bonding in the case of polyurethane-based adhesives but also allows adhesive residues to remain on the core and / or top layer after peeling. In this way, accidental peeling during wetting of the panel can be prevented. Preferably, the switchable adhesive is solvent-free.

[0029] Preferably, the panels according to the invention are interconnectable panels. For this purpose, each panel preferably includes at least one pair of opposing side edges provided with complementary corresponding interconnecting profiles, such as tongue and groove profiles, thereby allowing adjacent panels to be connected to each other, wherein the interconnecting profiles are preferably configured to achieve both horizontal and vertical locking effects. The horizontal locking effect is a locking effect within a plane defined by the panel, while the vertical locking effect is a locking effect perpendicular to the plane defined by the panel. In particular, it is preferred that the interconnecting profiles are integral parts of the core layer of the panel. In this case, it is further preferred that the interconnecting profiles allow the connection of two panels by vertical and / or tilting movements of the respective side edges. Preferably, a first pair of opposing side edges includes interconnecting profiles configured to allow adjacent panels to be connected by vertical movement (also referred to as downward movement, downward folding movement, or pull-down movement). Preferably, a second pair of opposing side edges includes interconnecting profiles configured to allow adjacent panels to be connected by downward tilting movement.

[0030] It is worth noting that, given the aforementioned preferred dimensions of the panel, the panel is satisfactory for recycling purposes, both in terms of the process of thoroughly peeling off the two adhesive layers and in terms of performing a treatment in which the switchable adhesive is exposed when it is present between the two adhesive layers.

[0031] In the panel according to the invention, preferably, the switchable adhesive comprises an unreacted unsaturated compound and / or one or more polymers having unreacted unsaturated groups, particularly pressure-sensitive adhesives (PSA), particularly methacrylate-functionalized PSA, and preferably, the adhesive strength of the switchable adhesive can be adjusted by exposure to irradiation.

[0032] Switching a switchable adhesive by irradiation results in a relatively simple, clean, and solvent-free process. Suitable irradiation sources include, for example, halogen lamps (wavelength preferably less than 700 nm), LED lamps, and microwave generators. Irradiation time is typically a few seconds, e.g., 2-4 seconds. The power of the irradiation source can vary, but is preferably at least 500 watts. Before switching, the bond strength of the switchable adhesive is typically between 25 N / mm² and 40 N / mm², while after switching, the bond strength is preferably less than 1 N / mm². Preferably, the top layer is at least partially permeable to irradiation produced by the irradiation source.

[0033] Adhesives containing unreacted unsaturated compounds or polymers with unreacted unsaturated groups are prone to crosslinking when exposed to light, including UV light. Crosslinking leads to further hardening of the adhesive, resulting in a reduction in bond strength. Depending on the specific circumstances, a reduction of up to 90% can be achieved.

[0034] Specific examples of adhesives suitable for use in this invention are pressure-sensitive adhesives (PSA), particularly methacrylate-functionalized PSA, i.e., unreacted vinyl groups that are readily crosslinked. Another key characteristic of PSAs suitable for use in this invention is that they possess a viscous state when forming an adhesive bond. The viscosity of the PSA largely determines the maximum achievable bond strength.

[0035] In the context of this invention, suitable formulations for PSA comprise a base binder polymer, an unreacted unsaturated compound or a binder polymer having unreacted unsaturated groups, and optionally a photoinitiator for enhancing the reaction of the unsaturated groups upon irradiation. The amount of photoinitiator present in the switchable binder is preferably in the range of 0.04 wt.% (weight percentage) to 10 wt.% of the switchable binder.

[0036] The base adhesive polymer may comprise polyacrylates, polyurethanes, and / or polysilicon. Unreacted unsaturated compounds may comprise alcohols, glycols, glycerols, epoxides, urethanes, silicones, polyesters, and polyethers in acrylate or methacrylate form. Adhesive polymers having unreacted unsaturated groups may include any type of propylene-functionalized polymer.

[0037] PSA can be used as an aqueous dispersion or produced as a solvent-free adhesive (so-called pressure-sensitive melt).

[0038] In the panel according to the invention, it is further preferred that the switchable adhesive comprises a mixture of crystallizable polymers that readily undergo phase transitions upon heating, such that the adhesive strength of the switchable adhesive can be adjusted by exposure to heat treatment.

[0039] Adhesives containing mixed crystallizable polymers are prone to phase transitions upon heating, which affects their physicochemical properties. After heating, the adhesive strength of such adhesives can decrease significantly, by up to approximately 90%.

[0040] In another preferred embodiment of the panel according to the invention, the switchable adhesive comprises one or more polymers having polar functional groups, such as methacrylate polymers, including polymethyl methacrylate, and the adhesive strength of the switchable adhesive can be adjusted by exposure to a pH modifier.

[0041] Some water-based adhesives can be enabled or disabled by changing the adhesive's pH value. For example, the adhesive strength of methacrylic polymers, including polymethyl methacrylate (PMMA), decreases significantly when the adhesive's pH value is below 3, and can be reduced by 90% or more.

[0042] Therefore, in this case, a decrease in adhesive strength can be caused by exposing the adhesive layer to a suitable acid.

[0043] In another preferred embodiment of the panel according to the invention, the switchable adhesive comprises a binary polymer brush, and the adhesive strength of the switchable adhesive can be adjusted by exposure to a solvent.

[0044] The adhesive strength of binders based on interlocking binary polymer brushes depends on the polarity of the solvent in which they are applied. For example, a greater difference in adhesive strength has been observed when the binder is in a non-polar organic solvent such as toluene compared to a polar solvent such as acidic water.

[0045] Therefore, in this case, the reduction in adhesive strength can be caused by contacting the adhesive layer with a suitable solvent, which significantly alters the interaction of the polymer brush.

[0046] Preferably, the reduction in adhesive strength of the switchable adhesive is at most 80% of the operating value of the adhesive strength of the switchable adhesive, more preferably at most 60%, and more preferably at most 40%.

[0047] In the panel according to the invention, it is particularly preferred that the top layer includes a decorative layer visible on the top side of the panel, and preferably comprises a polymer material. The decorative layer is preferably a (digitally)printed decorative layer, and typically consists of a paper or polymer layer on which ink is (digitally) printed.

[0048] In the panel according to the invention, it is further preferred that the top layer includes at least one abrasion-resistant layer, which preferably has transparent properties and / or contains a polymeric material. Typically, the top surface of the abrasion-resistant layer is covered by a top coating and / or lacquer layer, which can also be considered part of the (laminated) top layer. Both the abrasion-resistant layer and the top coating are transparent and / or translucent layers to ensure that the decorative layer is visible from the top view of the panel.

[0049] Preferably, the top layer has recesses, preferably recessed patterns. These recesses can be, for example, grooves, cavities, or alternative indentations. Preferably, at least a portion of the recess is aligned with at least a portion of at least one decorative image formed by the decorative layer. By applying this aligned arrangement, also known as alignment embossing, a very realistic and / or artistic design and appearance of the panel can be achieved. The decorative image can be formed from a wood pattern. However, it is easily imagined that the decorative image represents another pattern, such as a custom picture and / or mosaic or tile pattern. In the case of a mosaic or tile pattern, artificial tiles aesthetically separated by one or more grout lines can be depicted. Here, the top layer may also include thickened areas and / or protrusions to achieve a more realistic feel. Preferably, the recess covers at least 25% of the total surface area of ​​the upper surface of the panel, preferably at least 35%. In addition to the fact that these recesses, selectively applied in preferred locations (especially when aligned with the decorative image of the decorative layer), improve the appearance of the panel, these recesses also create weakened areas in the top layer that facilitate the switching of the switchable adhesive by direct irradiation beneath the recesses. This results in energy savings because less power is required to reach (irradiate) the switchable adhesive and thus switch it.

[0050] It is conceivable that the switchable adhesive only covers a portion of the facing surfaces of the two layers adhered to each other by the adhesive, and that the remaining portions of the facing surfaces are not covered by the switchable adhesive. This means that the switchable adhesive does not cover the entire contact surface of the two layers, but only a portion of it. This saves material and facilitates peeling because less adhesive needs to be switched. The portion where the switchable adhesive is present preferably comprises multiple regions, wherein adjacent regions may be connected to each other and / or adjacent regions may be positioned at a distance from each other, wherein these regions together preferably define a pattern, particularly a grid pattern. Preferably, these regions are applied selectively (rather than randomly), more preferably in a predetermined manner. Preferably, one or more adhesive regions define the pattern. Typically, one or more remaining (non-adhesive) regions define complementary patterns. The pattern defined by the adhesive regions may, for example, define a grid and / or matrix pattern and / or a dotted pattern. It is conceivable that at least one region is formed by multiple interconnected or intersecting line segments, wherein adjacent line segments enclose each other at an angle (between 0 and 180 degrees). Here, it is conceivable that at least two line segments are connected but do not intersect, which could result in shapes such as one of the following characters: W, E, T, Y, F, H, K, L, Z, V, N, M. However, it is also conceivable that at least two line segments intersect, which would result in shapes such as one of the following characters: +, X, *, #. Combinations of intersecting line segments and connected but non-intersecting line segments are also conceivable. Patterns composed of multiple broken lines (dashed lines or dashed line segments or dotted lines) can be applied. In this pattern, preferably, the broken lines are oriented substantially parallel to each other, but can also be defined, for example, as a matrix shape. Alternatively, one or more intermediate regions can, for example, have curved shapes, such as circular and / or oval and / or elliptical shapes, and / or can have polygonal shapes, such as square, rectangular, or triangular shapes.

[0051] Preferably, the adhesive region is at least partially aligned with at least a portion of the recess applied in the top layer. In this way, less switchable adhesive is used; furthermore, since the top layer directly above the adhesive region is thinner, less adhesive is relatively easy to switch. Therefore, preferably, the switchable adhesive region is at least partially located below the recess applied in the top layer.

[0052] In a particular embodiment of the panel according to the invention, the laminate of the panel further includes a backing layer disposed directly or indirectly on the underside of the core layer and adhered directly or indirectly to the core layer by a switchable adhesive.

[0053] In the panel according to the invention, it is particularly preferred that the core layer comprises a polymeric material, such as polyurethane or a polymer mixture comprising polyurethane.

[0054] Another preferred embodiment of the panel according to the invention is characterized in that the core layer comprises a polymer material, which is a mixture of recycled polymer material and virgin polymer material.

[0055] In the panel according to the invention, preferably, the panel includes two opposing side edges provided with corresponding interconnecting profiles that are complementary to each other, such as tongue and groove profiles.

[0056] This panel design allows for the construction of a covering consisting of multiple adjacent panels that are interconnected by means of an interlocking profile.

[0057] In this case, it is further preferred that the interconnecting profile allows the two panels to be joined by vertical and / or tilting movements of the respective side edges.

[0058] The second aspect of the invention relates to a floor covering, ceiling covering, or wall covering consisting of a plurality of adjacent panels according to the first aspect of the invention.

[0059] A third aspect of the invention relates to a method for recycling a panel after use, the panel being defined according to a first aspect of the invention, wherein the method comprises the following sequential steps:

[0060] i. Expose the switchable adhesive at the interface of the two adhesive layers of the panel to irradiation, heat treatment, solvent or pH modifier to adjust the adhesive strength to a reduction value suitable for recycling the panel;

[0061] ii. Peel the two adhesive layers off each other.

[0062] Preferably, the method according to the invention further includes the following subsequent steps:

[0063] iii. Recycle the two stripped layers in a separate stream.

[0064] Preferably, during step i, the switchable adhesive is exposed to irradiation using a halogen irradiation source or an LED irradiation source. Here, the switchable adhesive can be irradiated, for example, by light intensity of 10,000 to 15,000 lux from a 400 to 600 watt halogen lamp with a broad spectrum. Alternatively or additionally, during step i, the switchable adhesive is exposed to irradiation using a microwave irradiator with a typical power of 800 to 1,000 watts, wherein the microwave irradiator is preferably configured to generate irradiation at a frequency of 2.4 GHz. Attached Figure Description

[0065] The invention will be further described with reference to the preferred embodiments shown in the accompanying drawings, wherein:

[0066] Figure 1 A perspective view of the panel according to the present invention is shown;

[0067] Figure 2 A cross-sectional view of two panels and their connection profile according to the present invention is shown;

[0068] Figure 3 A cross-sectional view of two panels with alternative connection profiles according to the present invention is shown. Detailed Implementation

[0069] Figure 1 A panel 1 suitable for use as a floor panel, ceiling panel, or wall panel is shown. The panel has a flat design and has a top side 7, a bottom side, and side edges 3a-3d. The side edges 3a-3d include a first side edge 3a with a first profile 10 and a second side edge 3c with a second profile 11. A top layer 30 is present at the top side 7 of the panel.

[0070] Figure 2 It shows Figure 1 A cross-sectional view of panel 1 in a direction perpendicular to the first side edge 3a and the second side edge 3c, wherein the first side edge 3a and the second side edge 3c are provided with a first profile 10 and a second profile 11. The bottom side 9 of panel 1 is laid on a base layer, such as a floor surface S.

[0071] Panel 1 has a structure with laminated layers 28, 30, and 32 adhered to each other, these layers extending parallel to the plane of panel 1, and comprising:

[0072] It has a core layer 28 with a lower side and an upper side;

[0073] Top layer 30, which is adhered to the upper side of the core layer by a switchable adhesive according to the invention; and

[0074] Backing layer 32, which is adhered to the underside of the core layer by a switchable adhesive according to the invention.

[0075] In addition, Figure 2 In the figure, a portion of another identical panel 1' is shown, wherein the second side edge 3c of panel 1' is connected to panel 1 by a downward vertical movement as shown by vector D.

[0076] The first profile 10 and the second profile 11 of the two panels 1 and 1' are interacting profiles that can be joined together and are complementary to each other. During the joining process, the second profile 11 of panel 1' is vertically inserted into the first profile 10 of panel 1, which involves inserting the downward tenon 22 of panel 1' into the first groove 23 of panel 1 and the upward tenon 21 of panel 1 into the second groove 24 of panel 1'. When joined, panels 1 and 1' lie in a common plane parallel to the floor surface S.

[0077] Figure 3 It shows the relationship with Figure 2 Similarly, alternative connection profiles 40 and 41 are used to connect the two panels 1 and 1' to each other. Figure 2 The same features are indicated by the same reference numerals.

[0078] The first profile 40 of the panel 1' includes a lateral tenon 51 extending in a direction substantially parallel to the upper side of the panel, a downward wing 53 located at a distance from the lateral tenon 51, and a downward groove 54 formed between the lateral tenon 51 and the downward wing 53.

[0079] The second profile 41 of the panel 1 includes a groove 61 configured to receive at least a portion of the lateral tenon 51 of the first profile 40 of the second identical panel 1', the groove 61 being defined by an upper lip 62 and a lower lip 63, wherein the lower lip is provided with an upward locking element 64.

[0080] exist Figure 3 In the case shown, the first connecting profile and the second connecting profile 6 are configured such that the corresponding panels 1 and 1' can be connected to each other by a rotational movement indicated by arrow T, which involves inserting the lateral tenon of panel 1' into the third groove of another identical panel 1, wherein the upward locking element 64 of panel 1 is inserted into the second downward groove 54 of panel 1'.

[0081] The present invention can also be conceived of providing connecting contours 40 and 41 on side edges 3b and 3d, while side edges 3a and 3c are provided with alternative connecting contours 10 and 11, such as... Figure 2 As shown.

[0082] The above-described inventive concepts have been illustrated by several exemplary embodiments. It is conceivable that the various inventive concepts can be applied without applying other details of the described examples. It is not necessary to elaborate on all conceivable combinations of the above-described inventive concepts, as those skilled in the art will understand that numerous inventive concepts can be (re)combined to achieve a particular application.

[0083] The verb “include” and its variations used in this patent should be understood not only to mean “include”, but also to mean the phrases “contain”, “substantially constitute”, “formed by” and their variations.

Claims

1. A decorative panel with a planar design, the panel having a top side, a bottom side, and a plurality of side edges; The panel has a structure with multiple laminated layers adhered to each other, wherein the multiple laminated layers extend parallel to the plane of the panel and include: It has a core layer on the lower side and the upper side; And a rigid decorative top layer, the top layer being disposed directly or indirectly on the upper side of the core layer; wherein the panel includes at least a pair of opposing side edges, the side edges being provided with corresponding interconnecting profiles that are complementary to each other, wherein the interconnecting profiles are configured to achieve a horizontal locking effect and a vertical locking effect; wherein at least two layers of the laminated structure are adhered directly or indirectly to each other by a switchable adhesive having adjustable adhesive strength; wherein the switchable adhesive is starch-free and contains polyurethane; wherein by exposing the switchable adhesive present between the two adhesive layers to irradiation, the adhesive strength of the switchable adhesive can be adjusted from an operating value suitable for the panel during its use to a value suitable for the panel's recycling. The reduction value of the adhesive strength of the switchable adhesive promotes complete peeling of the two adhesive layers; and the top layer is at least partially permeable to irradiation for switching the switchable adhesive; the switchable adhesive contains at least one photoinitiator in a weight percentage ranging from 0.04% to 10% of the switchable adhesive; the reduction value of the adhesive strength of the switchable adhesive is at most 60% of the operating value of the adhesive strength of the switchable adhesive; and the switchable adhesive covers only a portion of the opposing surfaces of the two layers adhered to each other by the adhesive, and the remaining portion of the opposing surfaces is not covered by the switchable adhesive.

2. Panel according to claim 1, wherein The reduction in adhesive strength is 50% or less of the operating value.

3. Panel according to claim 1, wherein The planar design is rectangular or hexagonal.

4. Panel according to claim 1, wherein The panel has a length ranging from 0.40m to 2.0m, a width ranging from 70mm to 180mm, and a total thickness ranging from 2mm to 20mm.

5. Panel according to claim 4, wherein The total thickness of the panel is 3mm to 12mm.

6. Panel according to claim 1, wherein The core layer has a thickness of 2 mm to 7 mm, and / or the top layer has a thickness of 1 mm to 5 mm.

7. Panel according to claim 1, wherein The switchable adhesive has the form of an adhesive layer between the two adhesive layers, the adhesive layer being either a continuous layer or a discontinuous layer.

8. The panel according to claim 1, wherein, The switchable adhesive comprises an unreacted unsaturated compound and / or one or more polymers having unreacted unsaturated groups, and the adhesive strength of the switchable adhesive can be adjusted by exposure to irradiation.

9. Panel according to claim 8, wherein The polymer having unreacted unsaturated groups is a pressure-sensitive adhesive (PSA).

10. Panel according to claim 9, wherein The pressure-sensitive adhesive (PSA) is a methacrylate-functionalized PSA.

11. Panel according to claim 1, wherein The switchable adhesive comprises a mixture of crystallizable polymers that readily undergo phase transitions upon heating, allowing the adhesive strength of the switchable adhesive to be adjusted by exposure to heat treatment.

12. Panel according to claim 1, wherein The switchable adhesive comprises one or more polymers having polar functional groups, and the adhesive strength of the switchable adhesive can be adjusted by exposure to a pH modifier.

13. Panel according to claim 12, wherein The polymer having polar functional groups is a methacrylic acid polymer, including polymethyl methacrylate.

14. Panel according to claim 1, wherein The average molecular weight of the polyurethane is between 2,000 and 100,000.

15. Panel according to claim 1, wherein The switchable adhesive includes a binary polymer brush, and the adhesive strength of the switchable adhesive can be adjusted by exposure to a solvent.

16. Panel according to claim 1, wherein The reduction in adhesive strength of the switchable adhesive is at most 40% of the operating value of the adhesive strength of the switchable adhesive.

17. Panel according to claim 1, wherein The switchable adhesive is solvent-free.

18. Panel according to claim 1, wherein The switchable adhesive covers only a portion of the opposing surfaces of the two layers that are adhered to each other by the adhesive, and said portion includes multiple regions, wherein adjacent regions can be connected to each other and / or adjacent regions can be positioned at a distance from each other, wherein said regions together define a pattern.

19. Panel according to claim 18, wherein The top layer has a recess.

20. The panel according to claim 1, wherein, The top layer is provided with a recess that at least partially follows the decorative pattern of the decorative printed layer of the top layer.

21. Panel according to claim 19 or 20, wherein The recess covers at least 25% of the total surface area of ​​the upper side of the panel.

22. Panel according to claim 21, wherein The recess covers at least 35% of the total surface area of ​​the upper side of the panel.

23. Panel according to claim 19, wherein The area of ​​the switchable adhesive is at least partially aligned with at least a portion of the recess applied in the top layer.

24. Panel according to claim 1, wherein The top layer includes a decorative layer visible on the top side of the panel and comprises a polymer material.

25. Panel according to claim 1, wherein The top layer includes a wear-resistant layer, which has transparent properties and / or contains a polymer material.

26. Panel according to claim 1, wherein The laminate of the panel further includes a backing layer disposed directly or indirectly on the underside of the core layer and adhered directly or indirectly to the core layer by the switchable adhesive.

27. Panel according to claim 1, wherein The core layer contains a polymer material.

28. Panel according to claim 27, wherein The polymer material is polyurethane or a polymer mixture containing polyurethane.

29. Panel according to claim 1, wherein The core layer comprises a polymer material, which is a mixture of recycled polymer material and virgin polymer material.

30. Panel according to claim 1, wherein At least the core layer and the top layer comprise a polyurethane-based polymer material, and the switchable adhesive is based on polyurethane.

31. Panel according to claim 30, wherein Each laminate of the panel comprises a polyurethane-based polymer material.

32. Panel according to claim 1, wherein The panel includes two opposing side edges, which are provided with corresponding interconnected profiles that are complementary to each other.

33. Panel according to claim 32, wherein The corresponding interconnecting profiles that are complementary to each other are the tenon profile and the groove profile.

34. Panel according to claim 32, wherein The interconnecting profile allows the two panels to be joined by vertical and / or tilting movements of the respective side edges.

35. Panel according to claim 1, wherein The panel is a decorative panel, and the top layer thereon is a decorative top layer.

36. Panel according to claim 1, wherein The top layer is a rigid top layer.

37. Panel according to claim 1, wherein The top layer comprises a laminate with multiple sub-layers, the multiple sub-layers including at least one decorative printed layer and at least one translucent and / or transparent protective layer covering the decorative printed layer.

38. Panel according to claim 37, wherein The interconnecting profile allows the two panels to be joined by vertical and / or tilting movements of the respective side edges.

39. Panel according to claim 37 or 38, wherein The panel includes two pairs of opposing side edges, wherein each pair of opposing edges is provided with corresponding interconnected profiles that are complementary to each other.

40. A floor covering, ceiling covering, or wall covering comprising a plurality of adjacent panels as described in any one of claims 1 to 39.

41. A method for recycling a panel after use, the panel being defined according to any one of claims 1 to 39, wherein the method comprises the following sequential steps: i. exposing the switchable adhesive at the interface of two adhesive layers of the panel to irradiation, heat treatment, solvent, or pH modifier to adjust the adhesive strength to a reduced value suitable for recycling the panel; ii. peeling the two adhesive layers off each other.

42. The method of claim 41, further comprising the following subsequent step: iii. recovering the two stripped layers in a separate stream.

43. The method of claim 41 or 42, wherein, During step i, the switchable adhesive is exposed to irradiation using a halogen irradiation source or an LED irradiation source.

44. The method of claim 41, wherein, During step i, the switchable adhesive is exposed to irradiation using a microwave irradiator configured to generate irradiation at a frequency of 2.4 GHz.

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