Method and system for attaching a substrate element to a plate element and related plate element

Abstract

The invention discloses a method for attaching a sublayer element (23) to a weight-reduced plate element (1). The method comprises providing a plaque element and an underlying element, wherein the backside (4) of the plaque element comprises a trench portion and a remainder portion. The trench portion comprises at least one trench (10). An adhesive (20) is applied to at least a portion of the remainder of the lower layer element and / or to at least a portion of the corresponding remainder, and the lower layer element is arranged on the rear side of the plate element such that the adhesive contacts the lower layer element and the rear side.

Description

[0001] This application is a divisional application of the invention patent application with the application date of October 2, 2020, the application number of 202080070998.6, and the invention name of "Method and System for Attaching a Sub - layer Element to a Panel Element and Related Panel Elements". Technical Field

[0002] The present disclosure generally relates to sub - layer elements of panel elements such as panels. More specifically, the present disclosure relates to a method and system for applying a sub - layer element to a panel element such as a panel, wherein the back surface of the panel element includes at least one groove. The present disclosure also relates to the panel element itself, such as a panel. The panel can be a building panel, a floor panel, a wall panel, a ceiling panel, or a furniture panel. Generally, a panel such as a floor panel can include a thermoplastic material or a thermosetting material. The floor panel can be a luxury vinyl tile (LVT tile), a stone - plastic (polymer) composite panel (SPC panel), an expanded polymer core panel (EPC panel), or a wood - plastic composite panel (WPC panel). Alternatively, the panel can include an HDF core panel and optionally at least one wood - fiber - based layer. In some embodiments, the panel can be a mineral - based panel, such as a cement panel or a panel containing magnesium oxide and optionally magnesium chloride and / or magnesium sulfate. Background Art

[0003] It is well known that a substrate can be provided under a panel such as a floor panel to improve some of its characteristics. For example, the sound characteristics, feel, elasticity, thermal characteristics, permeability characteristics, and energy absorption of the panel can be affected.

[0004] The substrate can be loosely placed on the sub - structure such as the sub - floor on which the panel is installed, but can also be glued to the panel and / or the sub - structure.

[0005] Patent US 9,109,108B1 discloses a method of installing a floor on a floor substrate, wherein a first adhesive layer is applied to the floor substrate. A certain hybrid substrate including an extruded thermoplastic sheet having a plurality of inflated and expanded thermoplastic microspheres distributed therein is placed on the first adhesive layer. A second adhesive layer is applied to the hybrid substrate, and then a plurality of interface LVT floor units are placed on the second adhesive layer.

[0006] Publication US2012 / 0291387A1 discloses a floor system including an upper floor, a lower floor, and / or a substrate material disposed between the lower floor and the upper floor. The upper floor can include a plurality of luxury vinyl tiles configured such that corresponding tile joints can be formed between adjacent luxury vinyl tiles. The substrate material can include a cross - linked polyolefin foam.

[0007] Recently, there has been increasing interest in weight-reduced panels. One way to achieve weight reduction is to remove material from the back of the panel. WO 2013 / 032391 discloses floor panels including a plastic core layer, such as LVT floor panels, which include flex grooves for increasing their flexibility and for reducing their weight. Additionally, WO 2014 / 007738 discloses building panels, such as floor panels, which comprise a thermosetting resin or a thermoplastic material, preferably comprising a filler, and are provided with core board grooves.

[0008] WO 2013 / 032391 generally describes that a substrate such as foam can cover the flex grooves. Additionally, WO2014 / 007738 describes that a separate cover layer - such as paper, plastic foil, foam, cork or solid wood veneer - can cover the core board grooves to provide a moisture barrier seal or to reduce sound. However, there is still room for improvement, particularly with regard to the method for providing a substrate on the panel. Summary of the Invention

[0009] Accordingly, at least one object of embodiments of the present inventive concept is to provide a method for attaching a lower element such as a lower unit to a weight-reduced and / or flexible panel element such as a panel, which method may require a smaller amount of adhesive.

[0010] At least another object of embodiments of the present inventive concept is to provide such a more cost-effective method.

[0011] At least yet another object of embodiments of the present inventive concept is to provide a corresponding system.

[0012] In addition, at least one object of embodiments of the present inventive concept is to provide a corresponding panel element, such as a panel, to which a lower element such as a lower unit is attached.

[0013] At least some of these and other objects and advantages will become apparent from the description and have been achieved by the various aspects described below.

[0014] According to a first aspect of the present inventive concept, there is provided a method for attaching a lower element such as a lower unit to a panel element such as a panel. The method comprises: providing a panel element, wherein the back surface of the panel element includes a groove portion and a remaining portion, the groove portion including at least one groove; providing a lower element; applying an adhesive on at least a part of the remaining portion and / or on at least a part of a corresponding remaining portion of the lower element; and arranging the lower element on the back surface of the panel element such that the adhesive contacts the lower element and the back surface.

[0015] The method may sequentially include providing the panel element and / or the lower element, applying the adhesive, and arranging the lower element on the back surface.

[0016] Typically, the adhesive can adhere or attach the lower element to the back surface.

[0017] The grooves can reduce the weight of the panel element. By means of the groove portion, the surface area of the back surface becomes smaller. Thereby, the contact area between the back surface and the lower element can be reduced. Therefore, by selectively applying the adhesive according to the first aspect and its embodiments, a smaller amount of adhesive can be required to attach the lower element to the panel element.

[0018] On the remaining part and / or the residual part, the adhesive can be applied to, for example, 95% of the surface area only or substantially only. Thereby, the application of the adhesive in the groove portion can be avoided. The groove portion can be free of adhesive.

[0019] The panel element can be the panel itself, such as a floor panel, or it can be divided into at least one panel, such as at least two panels, such as floor panels. The panels can be substantially similar. It should be emphasized that throughout this disclosure, any embodiment involving a panel element can also be an embodiment involving the panel itself. However, it should be noted that the panel can include or can be intended to include a locking system for horizontal and / or vertical locking, preferably a mechanical locking system. The locking system of the panel can be preformed before applying the adhesive and attaching the lower element to the panel, or it can be post-formed after attaching the lower element to the panel.

[0020] The mechanical vertical locking system can include a tenon tongue and a tenon groove, which are configured to cooperate with the tenon groove and the tenon tongue provided on adjacent panels, respectively. In a first example, the tenon tongue is integrally formed with the panel. In a second example, the tenon tongue is separately formed from the panel. The separately formed tenon tongue can be a preferably flexible and movable tenon tongue disposed in the insertion groove. The mechanical horizontal locking system can include locking elements provided on a locking bar and locking grooves configured to cooperate with the locking grooves and the locking elements provided on the locking bars of adjacent panels, respectively.

[0021] The panel element can extend in a first (X) and a second (Y) horizontal direction that can be perpendicular to each other. In a first example, the first and second horizontal directions extend parallel to the long side portion and the short side portion of the panel element, respectively. In a second example, the first and second horizontal directions extend parallel to the short side portion and the long side portion of the panel element, respectively. The vertical direction (Z) of the panel element can be perpendicular to the first and second horizontal directions. The thickness of the panel element can be the extension of the panel element in the vertical direction.

[0022] The at least one groove can have a longitudinal extension and a transverse extension. The longitudinal extension can be greater than the transverse extension. The longitudinal extension can be parallel to the first horizontal direction.

[0023] At least one groove of the panel can be provided inside the back surface, spaced apart from a pair of opposite edge portions of the panel (such as opposite short side portions), preferably spaced apart from all edge portions of the panel.

[0024] Similarly, the lower layer elements can extend in first and second horizontal directions perpendicular to each other. The first and second horizontal directions of the lower layer elements can be parallel to the first and second horizontal directions of the plate elements respectively.

[0025] The plate element can further include a front surface disposed on the opposite side relative to the back surface. The front surface can be adapted to be visible, and at least in some embodiments, the back surface can be adapted to be hidden in the installed state of the plate element or the panel. Generally, the panel can be a building panel, a floor panel, a wall panel, a ceiling panel or a furniture panel.

[0026] The plate element or the panel can include a pair of opposite edge portions. The plate element or the panel can include a first pair and a second pair of opposite edge portions, such as including the long side portions and the short side portions of the plate element / panel respectively. A locking system for horizontal and / or vertical locking - preferably a mechanical locking system - can be provided on the long side portions and / or the short side portions of the panel.

[0027] Generally, the plate element or a panel such as a floor panel can include a thermoplastic material or a thermosetting material. In a first example, a panel such as a floor panel can be an LVT tile, an SPC panel, an EPC panel or a WPC panel. In a second example, the panel can include a core board, such as an HDF core board, and optionally at least one wood fiber-based layer attached to the core board. The at least one wood fiber-based layer can include a powder mixture that contains wood powder or wood fibers. In addition, the wood fiber-based layer can include a thermosetting resin, such as melamine-formaldehyde resin or urea-formaldehyde resin, and optionally pigments. The thermosetting resin and / or pigments can be provided in the powder mixture. Optionally, a wood covering, such as wood chips, can be provided on the at least one wood fiber-based layer. The floor panel can be the panel or the panel.

[0028] In some embodiments, the panel can be a mineral-based panel, such as a cement panel, or a panel that contains magnesium oxide and optionally magnesium chloride and / or magnesium sulfate. For example, the panel can be or can include a magnesium oxide (MgO) panel, a cement plate or a fiber cement plate. In particular, the back surface can include any of the above materials.

[0029] Providing for attaching the lower layer elements to the back surface can hide at least some of the grooves, preferably all of the grooves.

[0030] The groove portion can be formed integrally with the plate element. Thus, the material composition of the back surface and at least some portions of the groove portion can be substantially similar.

[0031] Generally, the groove portion can be formed by removing material from the back surface. Alternatively, the groove portion can be formed, for example, by heat and pressure when forming the plate element or the panel.

[0032] The remaining portion can be in a horizontal plane extending along the back surface of the plate element. Thereby, increased adhesion between the back surface and the underlying element can be provided. In a first example, the remaining portion is smooth. In a second example, the remaining portion includes a certain surface roughness, for example, including peaks and valleys, and the peaks preferably extend vertically from the valleys by less than 0.5 mm, for example, less than 0.35 mm. For example, an adhesive can be provided on the peaks, preferably such that no or substantially no adhesive is applied in the valleys.

[0033] Throughout this disclosure, it should be understood that each embodiment and example, etc. discussed with respect to the plate element in the first, second, third, fourth, and fifth aspects is equally applicable to the panel.

[0034] In some embodiments, a panel, such as a furniture panel or a building panel, can be configured to be a component in a panel arrangement structure such as a furniture arrangement structure. In some embodiments, a panel such as a building panel, a floor panel, a wall panel, or a ceiling panel can be configured to be mounted on and / or connected to a lower structure, such as a profile grid or a subfloor.

[0035] When provided as a floor, the panel with the underlying element attached thereto can be configured to be mounted on the subfloor in a floating manner. Thereby, it may not be necessary to apply an attachment member such as an adhesive to the lower side of the underlying element.

[0036] A panel such as a floor panel can be configured to be attached to a lower structure such as a subfloor, for example, by an adhesive. In some embodiments, the panel can be configured to be loosely mounted on a base structure such as a subfloor without using any locking system that interlocks the panels.

[0037] In some embodiments, the adhesive can be applied on substantially the entire remaining portion and / or substantially the entire corresponding residual portion.

[0038] The adhesive can be applied on the upper side of the underlying element. Thereby, the upper side can be attached to the back surface. The adhesive can contact at least a portion of the underlying element and can be provided between the underlying element and the back surface.

[0039] When the lower layer element is attached to the back surface, the corresponding remaining part can be configured to face and align with the remaining part of the back surface. The lower layer element can further include a cover portion configured to face and align with the groove portion when the lower layer element is attached to the back surface. The cover portion can cover the groove portion. Preferably, no adhesive is applied to the cover portion. The corresponding remaining part and the cover portion can be the corresponding surface parts on the upper side.

[0040] The adhesive can be any known adhesive known in the art, such as glue, which is preferably compatible with the material of the plate element (such as the material of the back surface) and the material of the lower layer element (such as the material of its upper side).

[0041] The method can further include curing or hardening the adhesive.

[0042] The adhesive can be applied by an adhesive applicator.

[0043] The adhesive can be applied during the displacement of the plate element and / or the lower layer element along the feed path. Thus, the method can become more time-saving. In addition, the method can be implemented in a continuous processing process. The adhesive can be applied online.

[0044] The arrangement of the lower layer element on the back surface can be performed during the displacement of the plate element and / or the lower layer element in the feed path.

[0045] The application of the adhesive and / or the arrangement of the lower layer element on the back surface can be carried out in a continuous processing process - for example, during the feeding of the lower layer element and / or the plate element in a continuous processing process - for example, by using rollers. For example, when the lower layer element includes an elastic material such as foam, a continuous processing process may be suitable, but it can also be used when the lower layer element (preferably in the form of at least one lower layer unit) is configured to be delivered separately.

[0046] In some embodiments, the application of the adhesive and / or the arrangement of the lower layer element on the back surface can be carried out in a discontinuous process. For example, when the lower layer element (preferably in the form of at least one lower layer unit) can be delivered separately, for example, in the form of at least one cork board, a discontinuous processing process may be suitable.

[0047] The adhesive can be applied at least on the peripheral part of the back side and / or on the peripheral part of the upper side of the lower element, and any one or both of the peripheral parts preferably extend along the short side part and / or the long side part of the panel element (or panel) and / or the lower element (or lower unit). The peripheral part can be provided in the remaining part and / or the corresponding remaining part. The peripheral parts of the back side and the upper side can be respectively located in the horizontal outsides of the back side and the upper side, preferably near their edge parts, such as the short side part or the long side part. The peripheral part can be positioned within a distance of 10%, preferably 5%, of the total length of the panel element or the lower element from the horizontal outermost part of the back side or the upper side. Alternatively or additionally, the peripheral part can be positioned within a distance of 20 mm, preferably 10 mm, from the horizontal outermost part.

[0048] The peripheral part of the panel element can include the peripheral part of at least one panel, such as at least two panels, and the panel element is configured to be divided into the at least two panels. Alternatively or additionally, the peripheral part of the lower element can include the peripheral part of at least one lower unit, such as two lower units, and the lower element is configured to be cut into the two lower units. The peripheral part of at least one panel and / or the lower unit can extend along the short side part and / or the long side part of the panel / lower unit.

[0049] As will be further detailed below, the application of the adhesive can be controlled such that no or substantially no adhesive is applied in at least one cutting part and / or at least one dividing part. Optionally, the application of the adhesive can be controlled such that no or substantially no adhesive is applied in the back side part in which, for example, the locking system of at least one panel is configured to be formed. Optionally again, the application of the adhesive can be controlled such that no or substantially no adhesive is applied in the upper side part of at least one lower unit, which upper side part is configured to contact a part of the at least one panel and in which the locking system is configured to be formed. Thus, the need to apply adhesive in some parts may become redundant as they are intended to be processed, such as divided, cut, or processed to form a locking system. Thereby, the amount of adhesive used can be further reduced.

[0050] The peripheral part can continuously extend around the periphery of the back side and / or the upper side - for example along the short side part and / or the long side part of the panel element and / or the lower element. For example, the groove part can be separated from the peripheral part of the back side and / or the cover part can be separated from the peripheral part of the upper side.

[0051] Alternatively or additionally, in order to apply the adhesive to the peripheral portion, the adhesive can be applied to the remaining portion inside the back surface, for example, the inside of the peripheral portion. For example, the adhesive can be applied to the inner sides of a pair of outermost grooves that preferably extend longitudinally along a first horizontal direction, such as along the long side portion of the panel.

[0052] The method can further include controlling the application of the adhesive based on the characteristics of at least one groove. Thereby, the adhesive can be selectively applied to a desired area, such as the remaining portion and / or the corresponding remaining part. The characteristic can be the shape of at least one groove and / or the extension length of at least one groove in the first and / or second horizontal directions of the plate element. Alternatively or additionally, the characteristic can be the position of at least one groove in the back surface and / or the distance between at least a pair of grooves in the first and / or second horizontal directions or the distance between at least a pair of grooves in the first and / or second horizontal directions, and each groove arrangement structure includes at least one groove, preferably including a plurality of grooves.

[0053] The application can be controlled by a control unit. The control can include controlling the position of the adhesive on the plate element and / or the underlying element, and optionally the amount of the adhesive. By changing the applied amount, the thickness and / or width of the adhesive can be changed, for example, along the application direction of the adhesive. The application direction can be parallel to the feeding direction of the plate element and / or the underlying element.

[0054] The control can be based on data related to the characteristics of at least one groove. In some embodiments, the data related to the characteristics can be retrieved by the control unit from a data storage unit in which the data can be stored. In some embodiments, the data can be collected by a data collection unit during or before the operation of the system implementing the method disclosed herein. For example, the data can be obtained by scanning the back surface with a scanner. In some embodiments, the data related to the characteristics can be predetermined. For example, the data related to the shape, extension, any position, etc. can be predetermined. In some embodiments, the collected and predetermined data can be combined. In still other embodiments, the data related to the characteristics can determine the position of the adhesive applicator (such as a roll coater or a slot die coater) relative to the plate element and / or the underlying element during the adhesive application. For example, and as outlined above, the data can be predetermined data and / or the collected data.

[0055] Generally, the method can include retrieving data related to the characteristics of at least one groove to control the application of the adhesive.

[0056] The position of the lower component may have to be controlled, for example synchronously, with the position of the plate component such that the lower component can be aligned with the plate component. In a first example, the cover part may be aligned with the groove part and the corresponding remaining part may be aligned with the remainder. Preferably, no adhesive is applied in the cover part. Synchronization may be particularly important in embodiments where the adhesive has already been applied to the lower component. In a second example, the lower component and the horizontal outermost part of the back side may be aligned, as described elsewhere herein for example. The first and second examples may be combined. Synchronization may be controlled by a control unit.

[0057] The adhesive may be applied by contact application - for example by slot die coating or by roll coating - to be applied. Roll coating and slot die coating may be applied by a roll coater and a slot die coater respectively. By the contact method, the application amount of the adhesive can be controlled more precisely. An advantage of roll coating is that the adhesive can be mainly applied in the remainder. An advantage of slot die coating is that the adhesive can be applied more evenly. In some embodiments, when the surface structure of the back side is too rough, it may be preferable to use slot die coating on the lower component.

[0058] Throughout the present disclosure, the plate component and / or the lower component may generally be referred to as the substrate. Thus, the adhesive may be applied on the substrate, for example on the plate component and / or the lower component.

[0059] The adhesive may be applied on the substrate by slot die coating from any direction. For example, when the substrate is provided in an inclined, vertical or horizontal position or fed in an inclined, vertical or horizontal direction, the adhesive may be applied from above or from below.

[0060] When the substrate is continuously fed by a roll, for example when the substrate - such as the plate component and / or the lower component - is flexible and / or soft, slot die coating or roll coating may be used.

[0061] Roll coating can apply the adhesive in a wide range of applications, as described in detail below.

[0062] The adhesive may be applied by non-contact application, for example by spraying or curtain coating. Spraying and curtain coating may be applied by a sprayer and a curtain coater respectively. By the non-contact method, the adhesive can be applied at a certain distance from the substrate. Thereby, the accumulation of dirt in the adhesive applicator can be reduced or even avoided.

[0063] The adhesive can be applied continuously or intermittently, for example, along the feed path of the panel element and / or the underlying element. Continuous or intermittent application can cause the adhesive to extend continuously or discontinuously along at least a portion of the panel element and / or the underlying element in a first or second horizontal direction, e.g., along the entire panel element. By intermittent application, less adhesive may be required. The continuous or intermittent application can be controlled according to any of the control embodiments described herein.

[0064] Intermittent application can be envisaged in any of the contact or non-contact applications described herein. In a first example, intermittent application can be achieved by bringing a roller coater into contact with and separating it from the panel element and / or the underlying element while shifting it along the feed path. In a second example, intermittent application can be implemented by transfer application, e.g., by using a combination of a transfer roller and an adhesive unit (such as a slot die and a roller coater). In a third example, intermittent application can be implemented by intermittently applying non-contact (e.g., by spraying or curtain coating) while shifting the panel element and / or the underlying element along the feed path.

[0065] The adhesive can be applied in a line application or a wide application manner. In line application, the adhesive can be applied along the first and / or second horizontal direction of the panel element and / or the underlying element. In addition, line application can apply the adhesive on at least a portion of the width of the back side or the upper side, e.g., between its corresponding short side portion or long side portion. For example, line application can cover less than 20% of the width, e.g., less than 10% or less than 5%. Wide application can apply the adhesive on substantially the entire width of the back side and / or the upper side, e.g., between its short side portion and / or long side portion. Obviously, in any of the embodiments disclosed herein, the adhesive is preferably applied only on the remaining portion and / or the corresponding residual portion.

[0066] Line application can be achieved by, for example, spraying, slot die coating, or roller coating. Wide application can be achieved by, for example, roller coating, spraying, slot die coating, or curtain coating.

[0067] Either continuous application or intermittent application can be line application or wide application. In addition, continuous application can extend between a pair of edges of the panel element and / or the underlying element that can be conveyed along the corresponding feed path.

[0068] Continuous wide application can, for example, completely cover the remaining portion by using an adhesive for roller coating. Continuous or intermittent line application or intermittent wide application can partially cover the remaining portion with the adhesive.

[0069] Typically, the adhesive can be applied only in a dedicated area, for example, applied in a controlled manner. Thereby, the amount of adhesive used can be further reduced. The adhesive can be applied in a pattern arrangement, for example, applied on the remaining part and / or on the corresponding residual part. For example, the pattern arrangement can be obtained by continuous or intermittent application of the adhesive or even a combination thereof.

[0070] The pattern arrangement can be a main pattern. The main pattern can include the same basic application design that repeats. For example, the basic application design can be set in the form of a grid, or it can be circular, oval, or polygonal, such as triangular, square, or star-shaped, etc.

[0071] Optionally, the pattern arrangement can further include at least one additional pattern, such as a secondary pattern. The secondary pattern can include at least two main patterns. In a first example, the at least two main patterns can be spaced apart from each other. In a second example, the at least two main patterns can be juxtaposed or intertwined.

[0072] The pattern arrangement can be a predetermined pattern arrangement. In a first example, the pattern arrangement can be applied by controlling the ejection of the adhesive - for example, in pulses and / or in a pattern application, such as in a swirl pattern application. In a second example, the pattern arrangement can be applied by a gravure roll coater. For example, the applied adhesive can be provided as an embossing or texture. The surface of the gravure roll coater can include a plurality of structural elements, such as indentations and / or protrusions. The structural elements - for example, their positions on the roll coater and / or their shapes - can correspond to the pattern arrangement, such as an embossing or texture, including its basic application design. In a third example, the pattern arrangement can be applied by an intermittently operated slot die coater and / or by a line application. In a fourth example, the pattern arrangement can be applied by a slot die coater in combination with at least one mask.

[0073] The adhesive can be applied by transfer - for example, by using a transfer roll and an adhesive unit configured to distribute the adhesive on the transfer roll - on the plate element and / or the underlying element. For example, the adhesive unit can be a slot die coater. Thereby, a more flexible adhesive application operation can be obtained, for example, while maintaining the benefits of roll coating. Also, a gravure roll for obtaining the pattern arrangement may not be required. Additionally, it may be easier to control the application of the adhesive. For example, by changing the distribution of the adhesive from the adhesive unit on the transfer roll, the pattern arrangement and / or the intermittent application of the adhesive can be easily changed.

[0074] The thickness of the remaining part can be greater than the thickness of the groove part, and the main part of the remaining part preferably has a constant thickness. This thickness can be the distance between the front and back surfaces in the remaining part and / or the groove part, such as the maximum thickness. The main part can be at least 50% of the back surface area, such as at least 70% or at least 90%. In some embodiments, substantially the entire or the whole remaining part can have a constant thickness.

[0075] At least two grooves may have been formed discontinuously. The application of the adhesive can include applying the adhesive between the discontinuous grooves, for example, along the first and / or second horizontal directions of the plate element. Obviously, alternatively or additionally, the application of the adhesive can include applying the adhesive, for example, along the first and / or second horizontal directions of the underlying element between the corresponding cover portions of the underlying element.

[0076] The discontinuous grooves can be spaced apart from each other in the first and / or second horizontal directions of the plate element.

[0077] The longitudinal extension of the discontinuous groove can be parallel to the long side portion of the plate element.

[0078] The groove part can include at least two groove arrangements, and each groove arrangement includes at least two grooves, such as a plurality of grooves. Preferably, the grooves are discontinuous grooves of the plate element. The groove arrangements can be separated by a dividing portion, which preferably extends continuously, for example, along the second horizontal direction between the long side portions of the plate element. For example, the dividing portion can include a rectangular part. By means of the dividing portion, a more stable plate element can be provided.

[0079] In some embodiments, the longitudinal extension of the groove, such as the discontinuous groove, can be parallel to the short side portion of the plate element.

[0080] The plate element can include at least one layer, and the at least one groove can at least partially penetrate the at least one layer, such as at least the underlying layer. The at least one layer can include an upper layer. In addition, in some embodiments, the underlying layer can be a backing layer. The backing layer can be a balancing layer. The back surface can be provided in the underlying layer of the at least one layer, such as provided in the backing layer. Generally speaking herein, at least two layers of the plate element can be laminated together, for example, by heat and pressure, or bonded together by an adhesive.

[0081] The plate element can include at least two layers, and at least one reinforcing layer, such as a glass fiber layer, can be provided between the at least two layers, for example, provided as a mesh.

[0082] The at least one groove can completely penetrate the underlying layer, such as the backing layer.

[0083] At least one layer, optionally including an upper layer and / or a lower layer (such as a backing layer), may each include a polymer-based material, preferably a thermoplastic or a thermosetting material. Preferably, at least one layer, optionally including an upper layer and / or a lower layer, each includes a filler.

[0084] The lower layer unit may be arranged or attached to the back surface of the panel element or the panel. The panel element or the panel and the lower layer unit may have matching specifications with each other, such as area and / or shape. The area and / or shape of each lower layer unit may correspond to the area and / or shape of the back surface of the panel element or the panel, for example, be substantially the same. The shape may be rectangular or square. In the first example, before attaching the lower layer unit to the back surface, the area and / or shape of the lower layer unit corresponds to the area and / or shape of the back surface. In the second example, the lower layer element is attached to the back surface and then cut into lower layer units such that its area and / or shape corresponds to the area and / or shape of the back surface.

[0085] The lower layer element itself may be at least one lower layer unit. For example, at least one lower layer unit may be stored in a lower layer applicator, which may be configured to arrange the at least one lower layer unit on the back surface.

[0086] The lower layer element may be cut into at least one lower layer unit. The method may further include cutting the lower layer element along at least one cutting portion into at least one lower layer unit. For example, the lower layer element may be stored on a roll and may be fed from it to the lower layer applicator.

[0087] When the lower layer element is attached to the panel element, the lower layer element may be cut. In some embodiments, the method may include cutting only the lower layer element without processing or substantially not processing - for example, at least partially dividing - the panel element. The panel element may be divided after cutting. Thereby, a simple separation of the removed material elements can be provided, for example, in cases where they are to be recycled. In some embodiments, the method may include cutting the lower layer element and dividing the panel element, for example, performing the cutting and dividing in the same operation. Thereby, an efficient processing can be provided. However, the removed material elements may have to be separated, for example, in cases where they are to be recycled.

[0088] The lower layer element may be cut before attaching it to the panel element, for example, before arranging the lower layer element on the panel element.

[0089] In some embodiments, the lower elements - preferably their upper sides - and the horizontal outermost portions of the back sides can be aligned, for example, along their first and / or second horizontal directions. Thereby, a closer fit between the lower elements of adjacent mounting panels can be obtained, thus improving, for example, their waterproof sealing effect and the like. For example, the extension lengths of the lower elements in the first and / or second horizontal directions can be the same as or substantially the same as the extension lengths of the panels in the first and / or second horizontal directions.

[0090] In some embodiments, the lower elements provided on the back sides can include at least one chamfered portion. The chamfered portion can be preformed, or it can be formed after the lower elements have been arranged on the back sides.

[0091] Again, throughout this disclosure, it should be understood that when referring to the lower elements, it can itself be at least one lower unit, or it can be cut into at least one lower unit.

[0092] The lower elements can be cut by cutting tools such as rotary cutting devices, engraving devices, or knife devices. In some embodiments, each cutting portion can correspond to the width of the cutting tool.

[0093] The method can further include dividing the plate element into at least one panel, for example, at least two panels, along at least one dividing portion. The plate element can be divided by, for example, a dividing tool including a rotary cutting element such as a circular saw blade. In some embodiments, each dividing portion can correspond to the width of the dividing tool.

[0094] Each dividing portion can be provided along the first or second horizontal direction of the plate element. In a first example, each dividing portion can be provided parallel to the long side portion of the plate element. In a second example, each dividing portion can be provided parallel to the short side portion of the plate element.

[0095] The plate element can be divided after the action of arranging the lower elements on the back sides.

[0096] Obviously, in some embodiments, the plate element can be divided before arranging the lower elements on the back sides of at least one panel thus divided.

[0097] Generally, the method can further include controlling the application of the adhesive such that no or substantially no adhesive is applied to the back side portion of the plate element and / or the upper side portion of the lower element, and the upper side portion of the lower element is configured to be further processed, for example, by cutting the lower element, dividing the plate element, or forming a locking system. This can result in a simpler separation and / or recycling of the material elements of the plate element and the lower element.

[0098] The method may further include controlling the application of the adhesive such that no or substantially no adhesive is applied in at least one cut portion and / or at least one dividing portion. Thereby, in these portions, the underlying element can be more easily separated from the panel element.

[0099] The method may further include controlling the application of the adhesive such that no or substantially no adhesive is applied in the back portion or the upper side portion of the at least one underlying unit, preferably at least one locking system of the panel is configured to be formed at the back portion, and the upper side portion is configured to be disposed along (e.g., in contact with) the back portion.

[0100] During processing, such as during dividing and cutting, and optionally when forming the locking system, the panel element, and the underlying element, the material removed will generally be a mixture of material elements from the panel element, the adhesive, and the underlying element, thus complicating, for example, recycling. Accordingly, the method may further include separating, during or after processing the panel element and the underlying element, the material elements removed from the underlying element and the panel element, such as chips, shavings, or strips, for example, by separating the material elements based on at least one property of the underlying element and the panel element, respectively. The processing may include cutting the underlying element into at least one underlying unit and dividing the panel element into at least one panel. Alternatively or additionally, the processing may include forming a locking system on the panel element. Optionally, the material elements of the adhesive in contact with the panel element and / or the underlying element may also be separated, for example, based on at least one property of the adhesive.

[0101] The property may be a physical characteristic of the underlying element, the panel element, and the adhesive. More specifically, the separation may be based on at least one selected from the group consisting of the material composition of the material element, the size of the material element, the weight of the material element, the shape of the material element, and the density of the material element.

[0102] The method may include screening or sieving the material elements. This may be advantageous when the sizes of the material elements, for example, the material elements of the underlying element and the panel element, are different.

[0103] The method may include gravitational separation of the material elements, such as specific gravity separation. This may be advantageous when the sizes and / or shapes of the material elements, for example, the material elements of the underlying element and the panel element, are substantially the same.

[0104] The density of the underlying element may be less than the density of the panel element or the panel.

[0105] The separation may be based on density separation or cyclone separation. Alternatively or additionally, the material may be separated by using an air classifier. The separation may employ a dry separation method.

[0106] The adhesive can be applied to the back side and / or the underlying element at the application temperature of the adhesive. In a non-limiting example, the application temperature can be 5 - 150 °C, for example 10 - 120 °C. Generally, in a non-limiting example, an amount of 10 - 200 g / m 2 , for example 10 - 40 g / m 2 or 60 - 120 g / m 2 of the adhesive can be applied to the back side and / or the underlying element.

[0107] The adhesive can be a hot-melt adhesive. Preferably, the application temperature of the hot-melt adhesive during application is between 100 °C and 140 °C, for example 110 - 130 °C.

[0108] The method can include heating the adhesive, such as a hot-melt adhesive. Thereby, the application temperature of the adhesive can be achieved.

[0109] The hot-melt adhesive can be used in any of the application methods described herein, such as slot die coating, roll coating, spraying or curtain coating.

[0110] In a non-limiting example, an amount of 10 - 150 g / m 2 , preferably 60 - 110 g / m 2 , more preferably 70 - 90 g / m 2 of the hot-melt adhesive can be applied to the back side and / or the underlying element. In some embodiments, an alternative preferred amount is 10 - 100 g / m 2 , more preferably 10 - 50 g / m 2 .

[0111] Generally herein, the hot-melt adhesive can be reactive or non-reactive. In a non-limiting example, the hot-melt adhesive can be a reactive polyurethane (PUR) hot-melt adhesive, an ethylene-vinyl acetate (EVA) hot-melt adhesive, a polyolefin (PO) hot-melt adhesive, a copolyamide (CoPA) hot-melt adhesive or a rubber-based pressure-sensitive adhesive (PSA). The EVA hot-melt adhesive and the rubber-based PSA can be non-reactive. The PO hot-melt adhesive can be reactive.

[0112] The PUR hot-melt adhesive can provide strong adhesion between the panel element and the underlying element. A non-limiting list of examples of PUR hot-melt adhesives is KLEIBERIT 711.2.00, KLEIBERIT 706.1.38, H.B.Fuller Rapidex NP2075LT, Coating P. Materials PR-6620 and Jowatherm-Reaktant609.40. In a non-limiting example, the PUR hot-melt adhesive can be at 50 - 100 g / m 2 , preferably 70 - 90 g / m2 or sometimes in an amount of 10 - 100 g / m 2 、 preferably 10 - 50 g / m 2 is applied.

[0113] In some embodiments, the adhesive may be a cold adhesive. The cold adhesive may be a one - component (1C) adhesive or a two - component (2C) adhesive. The two - component adhesive may include an adhesive and a hardener. The cold adhesive may be a solvent - based adhesive. However, in some embodiments, an aqueous cold adhesive may be contemplated. The cold adhesive may be polyurethane (PUR), such as 1C PUR or 2C PUR, styrene copolymer (SBS), chloroprene rubber (CR), two - component epoxy adhesive or EVA. 1C PUR may cure wet. 2C PUR may contain isocyanate and polyol. In some applications, the cold adhesive is too slow for use in a fast production line. As a result, the cold adhesive may have to be post - treated, as discussed below. In a non - limiting example, 120 - 180 g / m 2 of the cold adhesive may be applied on the back side and / or on the underlying element.

[0114] In fact, the general adhesive can be post - treated, for example, after the adhesive is applied. The method may further include drying the adhesive and / or exposing the adhesive to radiation, such as infrared or ultraviolet radiation. The post - treatment may be carried out before and / or after arranging the underlying element on the back side. Preferably, the adhesive is exposed to UV radiation before arranging the underlying element on the back side. For example, the adhesive may be a UV - curable adhesive, such as an acrylic - based adhesive. Alternatively or additionally, the method may further include post - heating the adhesive, i.e., heating the adhesive when and / or after the adhesive is applied on the back side and / or on the underlying element. Preferably, the adhesive is heated before arranging the underlying element on the back side. Thereby, the adhesion performance of the adhesive can be increased. For example, the applied adhesive may be post - heated when its temperature drops below the working temperature. The working temperature may be the temperature above which the adhesion performance of the adhesive exceeds a certain threshold. The working temperature may be higher than the glass transition temperature Tg of the adhesive and / or higher than the melting point Tm of the adhesive. In a non - limiting example, the working temperature may generally be 5 - 150 °C, such as 10 - 120 °C, while for a hot - melt adhesive, the working temperature may be 100 - 140 °C, such as 110 - 130 °C. For example, the hot - melt adhesive may be a PUR adhesive. For example, the adhesive applied on the panel element may be post - heated after splitting the panel element and / or after forming a locking system on the panel. This can simplify the handling of the panel element and / or the underlying element.

[0115] In some embodiments, the post-treatment may include exposing at least a portion of the adhesive to moisture / water. Thereby, the curing of the moisture-curing adhesive can be activated and / or accelerated. In fact, the method may further include controlling the applied moisture content and / or the relative ambient humidity (RH). Preferably, the adhesive is exposed to moisture before the lower layer element is disposed on the back side.

[0116] The adhesive may be a pressure-sensitive adhesive, such as an acrylic-based adhesive or a rubber-based adhesive. In a non-limiting example, the PSA may be applied in an amount of 10 - 100 g / m 2 , preferably 15 - 50 g / m 2 , more preferably 20 - 30 g / m 2 .

[0117] Generally, the method may further include applying pressure on the lower layer element and / or the panel element, preferably during the curing or hardening of the adhesive. Such pressure application can be envisaged for any type of adhesive, including pressure-sensitive adhesives and hot-melt adhesives. Pressure can be applied on the lower layer element and / or the panel element, preferably such that at least a portion of the upper side - for example, the entire upper side - is pressed against the back side and / or abuts against the back side. By applying pressure, the adhesion of the lower layer element to the panel element can be increased.

[0118] The lower layer element may be formed continuously, without any slots. However, in some embodiments, the lower layer element may be formed discontinuously, including perforations and / or at least one slot. Thereby, the heat transfer from a lower structure such as a subfloor to the front side can be improved. For example, when attached, the at least one slot may be aligned with the at least one groove. Such alignment can be controlled when synchronizing the position of the lower layer element with the position of the panel element.

[0119] The lower layer element may include an elastic material. Thereby, the lower layer element can be disposed on a roller and can be more easily conveyed on the roller. Optionally, the lower layer element may be compressible.

[0120] The lower layer element may contain a rigid material.

[0121] The lower layer element may contain a thermoplastic material.

[0122] The lower layer element may be a foam, such as a closed-cell foam or an open-cell foam.

[0123] The lower layer element can comprise or can be irradiated cross-linked polyethylene or polypropylene foam (IXPE foam or IXPP foam), preferably EVA foam provided as a closed-cell foam, polyolefin (PO) foam such as cross-linked polyolefin foam (XLPO) or foam rubber. Additionally, the lower layer element can be polystyrene (PS) foam, such as extruded polystyrene (XPS), or polyethylene (PE) foam, such as expanded polyethylene (EPE) or cross-linked polyethylene foam (XLPE), or PET foam.

[0124] The lower layer element can be a cork-based lower layer element, such as cork sheets. For example, a cork-based lower layer element such as cork sheets can be stored on a roll and can be conveyed from the roll to the lower layer applicator.

[0125] The lower layer element can include a thermosetting resin, such as polyurethane (PU). For example, the lower layer element can be PU foam.

[0126] The thickness of the lower layer element, such as a foam-based or cork-based lower layer element, can be between 0.5 mm and 4 mm, for example between 1 mm and 2 mm. The thickness of a panel element such as a panel can be between 2 mm to and 40 mm, for example between 2 mm and 10 mm. The depth of the groove can be greater than 0.5 mm, for example greater than 2 mm.

[0127] The panel element can be a panel, and the method can further include forming a locking system for horizontal and / or vertical locking, preferably a mechanical locking system, on at least one edge portion of the panel, preferably on two opposite edge portions thereof (for example on all edge portions). In a first example, the locking system is formed before the lower layer element is arranged on the back surface. The area and / or shape of the lower layer element can correspond to the area and / or shape of the back surface of the panel including the locking system. In a second example, the locking system is formed after the lower layer element is set on the back surface. When forming the locking system, a part of the lower layer element may have to be removed.

[0128] It should be noted that the steps of the method according to any of the above embodiments are exemplary and do not have to be performed in the exact order disclosed.

[0129] According to a second aspect of the inventive concept, there is provided a panel element, such as a panel, which can be obtained by the method according to any of the embodiments of the first aspect. For example, the panel element in the method according to the first aspect can be a panel. The embodiments and examples of the panel element according to the second aspect are largely similar to the embodiments and examples of the first, third, fourth, and fifth aspects in which the panel element is mentioned.

[0130] According to a third aspect of the inventive concept, there is provided a system for attaching a lower element, such as a lower unit, to a panel element, such as a panel. The system includes an adhesive applicator and a lower applicator.

[0131] The adhesive applicator can be a contact applicator, such as a roll coater or a slot die coater, or a non-contact applicator, such as a sprayer or a curtain coater.

[0132] The adhesive applicator can be configured to apply the adhesive by transfer application.

[0133] The system can include a conveying device configured to convey the panel element and / or the lower element along corresponding feed paths.

[0134] The system can include a pressing device configured to apply pressure to the lower element and / or the panel element. For example, the pressing device can be provided by at least one roller and / or at least one conveyor belt.

[0135] The system can include a post-treatment device for post-treating the adhesive after application. The post-treatment device can be located upstream and / or downstream of the lower applicator along the feed path. In some embodiments, the post-treatment device is located at the lower applicator. The post-treatment device can include a drying device and / or a radiation device, such as an infrared or ultraviolet radiation device, configured to dry the adhesive and / or reduce the curing time or hardening time of the adhesive. Alternatively or additionally, the post-treatment device can include a post-heating device configured to heat the adhesive after the adhesive is applied to the panel element and / or the lower element. In some embodiments, the system can include a moisture regulator / humidity regulator for regulating the applied moisture and / or RH value. The moisture regulator can be located upstream of the lower applicator along the feed path.

[0136] The system can include a separating device configured to separate material elements, such as chips, shavings, or strips, removed from the lower element and the panel element during or after processing the panel element and the lower element, for example, by separating the material elements based on at least one property of the lower element and the panel element, respectively. The processing can include cutting the lower element into at least one lower unit and dividing the panel element into at least one panel. Alternatively or additionally, the processing can include forming a locking system on the panel element. In a first example, the locking system can be formed after the lower element is disposed on the back surface and the panel element is divided into at least one panel. In a second example, the locking system of the panel itself can be formed before the lower element is disposed on the back surface. Optionally, the material elements of the adhesive contacting the panel element and / or the lower element can also be separated, for example, based on at least one property of the adhesive.

[0137] The system may include machining tools, such as cutting tools and / or splitting tools.

[0138] The system may include a control unit. Additionally, the system may include a data storage unit and an optional data collection unit.

[0139] Embodiments and examples of the system according to the third aspect are largely similar to the embodiments and examples of the first, second, fourth, and fifth aspects in which the system is discussed.

[0140] According to a fourth aspect of the inventive concept, there is provided a panel assembly including a panel and a lower layer unit. The back surface of the panel includes a groove portion and a remaining portion, the groove portion including at least one groove. The lower layer unit is attached to the back surface of the panel by an adhesive that contacts at least a portion of the remaining portion and a corresponding remaining portion of the lower layer unit.

[0141] Embodiments and examples of the panel according to the fourth aspect are largely similar to the embodiments and examples of the first, second, third, and fifth aspects in which the panel is discussed. In particular, embodiments and examples of at least one selected from the group consisting of the material composition of the panel, the material composition of the lower layer unit, the design of the panel, and the design of the lower layer unit may be the same. Additionally, at least the following embodiments and examples may be contemplated.

[0142] The lower layer unit may be pre-mounted on the panel.

[0143] The thickness of the remaining portion may be greater than the thickness of the groove portion, and a major portion of the remaining portion preferably has a constant thickness.

[0144] The adhesive may be applied in a pattern arrangement.

[0145] At least two grooves may have been formed discontinuously. The adhesive may be provided, for example, between the discontinuous grooves along a first and / or second horizontal direction of the panel.

[0146] The panel may include at least one layer, and the at least one groove may at least partially penetrate the at least one layer, such as at least the lower layer.

[0147] The at least one layer—such as a backing layer—optionally including an upper layer and / or a lower layer may each include a polymer-based material, such as a thermoplastic material, and preferably includes a filler.

[0148] The lower layer unit may be a foam, such as a closed-cell foam or an open-cell foam, or may be embodied as any other embodiment described with respect to the first aspect.

[0149] According to a fifth aspect of the inventive concept, there is provided a method for attaching a lower element, such as a lower unit, to a panel element, such as a panel. The method includes: providing a panel element, wherein a back surface of the panel element includes a groove portion and a remaining portion, and the groove portion includes at least one groove; providing a lower element including a pre-applied adhesive; and disposing the lower element on the back surface of the panel element such that the adhesive contacts the lower element and the back surface.

[0150] The adhesive may be applied to at least a part of a corresponding remaining portion of the lower element. For example, the adhesive may be applied only to the corresponding remaining portion.

[0151] The method may further include synchronizing a position of the lower element with a position of the panel element such that the lower element becomes aligned with the panel element, preferably such that a cover portion is aligned with the groove portion and the corresponding remaining portion is aligned with the remaining portion.

[0152] The lower element may be provided with a peelable liner, such as a peelable film, and the method may further include removing the peelable liner before disposing the lower element on the back surface.

[0153] Embodiments and examples of the method according to the fifth aspect are largely similar to the embodiments and examples of the first aspect in which the method is discussed. In particular, embodiments and examples of at least one selected from the group consisting of the material composition of the panel element / panel, the material composition of the lower element / unit, the design of the panel element / panel, and the design of the lower element / unit may be the same. In addition, application details of the pre-applied adhesive, such as a pattern arrangement, may be the same as in the first aspect.

[0154] Other aspects of the inventive concept, as well as embodiments and examples of each of the first, second, third, fourth, and fifth aspects, are provided in the embodiments section below. It should be emphasized that embodiments and examples of any aspect may be combined with embodiments and examples of any other aspect.

[0155] Generally, all terms used in the claims should be interpreted according to their ordinary meaning in the technical field, unless otherwise clearly defined herein. All references to "a / the [element, device, component, apparatus, step, etc.]" should be construed to disclose at least one instance of the element, device, component, apparatus, step, etc., unless otherwise clearly stated. BRIEF DESCRIPTION OF THE DRAWINGS

[0156] The present disclosure will be described in more detail below in conjunction with exemplary embodiments and with reference to the accompanying exemplary drawings, in which:

[0157] Figures 1a - 1c An embodiment of a system for attaching a lower element to a panel element is shown in a perspective view.

[0158] Figures 2a - 2e An embodiment of an adhesive applicator is shown in perspective view, and an embodiment of a system for attaching a lower element to a panel element is shown in side view.

[0159] Figures 3a - 3d An embodiment of an adhesive applicator is shown in perspective view, and an embodiment of a system for attaching a lower element to a panel element is shown in side view.

[0160] Figure 3e An enlarged cross-section around the back surface of a panel element including a certain surface roughness is shown in side view.

[0161] Figures 4a - 4f Embodiments of panel elements and panels are shown in perspective, bottom, and side views, and a lower element is shown in top view.

[0162] Figures 5a - 5l An embodiment of attaching a lower unit to a panel is shown in side view and embodiments of a system and method for attaching a lower element to a panel element are shown in bottom and side views.

[0163] Figure 6 is a flowchart showing an embodiment of a method for attaching a lower element to a panel element.

[0164] Figures 7a - 7c An embodiment of a method for cutting a lower element attached to a panel and an embodiment of a method for forming a locking system on the panel are shown in side view.

[0165] Figure 7d An embodiment of the arrangement of a lower element on a panel element is shown in side view, wherein the lower element includes a pre-applied adhesive and is provided with a release liner.

[0166] Figures 8a - 8f An embodiment of a panel to which an adhesive has been applied is shown in bottom view.

[0167] Figures 9a - 9f An embodiment of a panel to which an adhesive has been applied is shown in top view and an embodiment of an adhesive applicator is shown in top and perspective views.

[0168] Figures 9g - 9h An embodiment of a lower element is shown in top view.

[0169] Figures 10a - 10d An embodiment of a lower element is shown in top view and an embodiment of a panel is shown in bottom view.

[0170] Figures 10e - 10f Embodiments of the panel element and the underlying element are shown in the bottom view and the top view respectively and in the side view. DETAILED DESCRIPTION

[0171] Next, reference will be made in particular to Figures 1a - 1c , 2a - 2e, 3a - 3e, 5a - 5l, 6 and 7a - 7c to describe embodiments of a method for attaching an underlying element 23, such as an underlying unit 23a, 23b, to the back surface 4 of a panel element 1, such as a panel 1', including at least one groove 10, and embodiments of a system 30 configured to implement the method. The panels involved generally refer to floor panels, such as thick boards or floor tiles, but it should be understood that in some embodiments, the panels can be building panels, wall panels, ceiling panels or furniture panels.

[0172] Figures 1a - 1c An embodiment of a system 30 for attaching an underlying element 23 to a panel element 1, such as a panel 1', is schematically shown in the side view. The system 30 includes an adhesive applicator 40 and an underlying applicator 31. The application of the adhesive 20 and / or the arrangement of the underlying element on the back surface can be carried out in a continuous processing operation.

[0173] As Figure 1a shown, the system can further include conveying devices 50, 51 configured to convey the panel element along a feed path FP and / or convey the underlying element along a feed path FP'. The feed direction FD of the panel element and the feed direction FD' of the underlying element can be parallel at least along a part of the feed path, for example at the position where the underlying element is arranged on the back surface 4. The conveying devices 50, 51 can be any conveying devices known in the art. For example, it can include at least one roller 50a, 50b, 51a, 51b, 51c that rotates in directions R1, R2, R3 and optionally includes a drive mechanism (not shown) for driving at least one of the rollers 50a - 50b, 51a - 51c, at least one conveyor belt 50c or the like. For clarity, in the embodiments disclosed herein, the conveying device 50 is sometimes omitted. At least one component of the underlying applicator 31 can be provided by the conveying device 51, for example by at least one roller 51c.

[0174] The speed of the panel element and the speed of the underlying element along the feed paths FP, FP' can be synchronized during the operation of the system 30, for example substantially the same. For example, the speed can be 3 - 130 m / min, such as 15 - 100 m / min or 20 - 50 m / min.

[0175] The system 30 may further include a frame 32, in which a lower applicator, an adhesive applicator, and optionally a conveying device are arranged. Preferably, the lower applicator, the adhesive applicator, and optionally the conveying device are fixedly mounted in the frame. It is understood that the frame 32 exists hereinafter, but for the sake of clarity, it will not be described in detail.

[0176] The lower applicator 31 may be loaded with a lower element 23, which is configured to be arranged on the back surface of the panel element. Generally, the lower element may include at least one lower unit 23a, 23b itself, or it may be cut into at least one lower unit 23a, 23b. The lower element may be cut into a suitable size by a cutting tool 52, which may be provided in the system 30, see for example Figures 1a - 1c and 2d. The cutting tool may include a rotary cutting device, an engraving device, or a knife device including at least one knife. In a first example, the cutting tool is fixedly mounted in the frame 32. In a second example, the cutting tool is shiftably mounted in the frame. The cutting tool 52 may be positioned downstream of the lower applicator 31 along the feed path FP’. Alternatively, as described above, the lower applicator may include at least one lower unit 23a, 23b, which may be stored therein and may be conveyed therefrom, see for example Figure 3d .

[0177] The adhesive applicator 40 may include or may be connected to an adhesive reservoir 42. In addition, a control unit 44 may control the application of the adhesive.

[0178] Figure 1a The embodiments in show schematically a general adhesive applicator 40, which may be a contact applicator, such as a roller coater 43 or a slot die coater 41, or a non-contact applicator, such as a sprayer 45 or a curtain coater 46. As Figure 1a shown, the adhesive applicator may be configured to apply the adhesive 20 to the panel element 1, such as the panel 1’. In addition, as Figure 1b shown, the adhesive applicator may be configured to apply the adhesive to the lower element 23, such as the lower units 23a, 23b. Moreover, as Figure 1c shown, the adhesive applicator may be configured to apply the adhesive to the panel element 1, such as the panel 1’, and to the lower element 23, such as the lower units 23a, 23b.

[0179] The position of the lower element may have to be synchronized with the position of the panel element so that the lower element becomes aligned with the panel element. The synchronization may be controlled by the control unit 44.

[0180] The adhesive can be a hot-melt adhesive, such as a PUR hot-melt adhesive, but other adhesives that are suitable for the intended purpose will be equally conceivable from the discussion herein.

[0181] In the first example, the panel can be an SPC panel, the PUR hot-melt adhesive can be KLEIBERIT 711.2.00, and the underlying element can be IXPE foam, EVA foam, or corkboard. In the second example, the panel can be an EPC panel, the PUR hot-melt adhesive can be H.B.Fuller Rapidex NP 2075LT, and the underlying element can be IXPE foam, EVA foam, or corkboard. In the third example, the panel can be an LVT tile, the PUR hot-melt adhesive can be H.B.Fuller RapidexNP 2075LT, and the underlying element can be IXPE foam, EVA foam, or corkboard.

[0182] As Figure 1a shown, the system 30 disclosed herein can further include a heating device 33 for heating the adhesive, such as a hot-melt adhesive, before application. For example, the heating device can heat the adhesive to the application temperature. The system 30 in any of the embodiments disclosed herein can further include a post-treatment device 34, such as a drying device and / or a radiation device, such as an infrared or ultraviolet radiation device. The post-treatment device can be located at the underlying applicator 31 and / or downstream thereof along the feed path FP’. However, alternatively or additionally, in some embodiments, the post-treatment device 34, such as an ultraviolet radiation device, can be located upstream of the underlying applicator 31. Alternatively or additionally, the system can include a post-heating device 36 configured to heat the adhesive after application of the adhesive. Such an embodiment is shown, for example, Figure 1c in

[0183] In some embodiments, and as Figure 1b shown, the post-treatment can include exposing the adhesive to moisture, for example, through a moisture regulator 39. In fact, the method can further include controlling the applied moisture content and / or the RH value. Preferably, the moisture regulator is provided upstream of the underlying applicator 31 along the feed path FP and / or FP’.

[0184] Optionally, system 30 may further include a pressing device 35 configured to apply pressure on the underlying element and / or the panel element, which is preferably located at the underlying applicator 31 and / or downstream thereof along the feed path FP'. At least one component of the pressing device 35 may be provided by the conveying devices 50, 51, such as by at least one roller 50b, 51c, or by at least one roller 51c and a part of the conveying device 50 such as at least one conveyor belt 50c, etc. For example, the distance between components of the conveying device through which the panel element is fed, such as between a pair of rollers or between a roller and a part of the conveyor belt, may be less than the combined thickness of the panel element and the underlying element (preferably including the adhesive).

[0185] As Figures 1b - 1c schematically shown in the embodiments of FIGS. 2a - 2b and 2e, the adhesive may be applied by contact application - for example by slot die coating or roll coating - as described above. Figure 1a The adhesive applicator 40 in FIGS. may be a contact applicator, such as a roll coater 43 or a slot die coater 41. Further, Figure 1c any one or both of the adhesive applicators 40 in FIGS. may be a contact applicator, such as a roll coater 43 or a slot die coater 41.

[0186] Figure 1b FIG. shows a slot die coater 41 applying an adhesive 20 on the underlying element 23 - for example directly thereon. The adhesive may be applied from below, for example when the underlying element is fed in a horizontal or inclined direction. Figure 2a A slot die coating on a substrate 60 is generally shown in perspective, which may be a panel element 1, such as a panel 1', or an underlying element 23, such as an underlying unit 23a, 23b. The slot die coater may form an adhesive coating on the substrate 60, which may be continuous in a direction TD or TD' transverse to the feed direction FD or FD', and in operation the directions TD, TD' are preferably parallel to the back surface 4. However, in some embodiments, the adhesive coating on the substrate 60 may be discontinuous in the direction TD or TD', see Figure 2e wherein the slot die coater is used in combination with at least one mask 40a. The adhesive may be deposited from at least one nozzle 41a extending in the transverse direction TD or TD', depending on whether the substrate is a panel element or an underlying element, respectively.

[0187] Figure 2bThe side view in [reference] shows an embodiment in which the adhesive applicator 40 includes at least one roller coater 43, such as an application roller 43a and a metering roller 43b, and preferably includes a doctor blade 43c. The adhesive applicator can apply the adhesive 20 to the panel element 1, for example, directly thereon. Generally speaking herein, it should be understood that at least one roller coater 43 can rotate during the application of the adhesive. Preferably, a rotation mechanism (not shown) can be configured to rotate at least one roller coater 43.

[0188] As schematically shown in side view and perspective view in the embodiments of [references] Figures 2c - 2d and 3a - 3b, the adhesive can be applied by non - contact application - for example, by spraying or curtain coating. It should be remembered that Figure 1a the adhesive applicator 40 in [reference] can be a non - contact applicator, such as a sprayer 45 or a curtain coater 46. In operation, the non - contact applicator can generally be spaced apart from the underlying element.

[0189] Figure 2c Generally shows the non - contact application of the adhesive 20 on the panel element 1 by the adhesive applicator 40 (such as a sprayer 45 or a curtain coater 46).

[0190] In addition, Figure 2d Generally shows the non - contact application of the adhesive 20 on the underlying element 23 by the adhesive applicator 40 (such as a sprayer 45 or a curtain coater 46). The application of the adhesive and / or the arrangement of the underlying element on the back side can be carried out in a continuous processing operation. The conveying devices 50, 51 configured to convey the panel element along the feed path FP and / or the underlying element along the feed path FP' can be implemented as described elsewhere in this disclosure, for example, by at least one roller 50a, 50b, 51a, 51b that rotates in the directions R1, R2, R3, and optionally includes a drive mechanism (not shown) for driving at least one roller, at least one conveyor belt or the like. Figure 2c Other features of the embodiments in [reference] can be similar to the embodiments described with respect to any of the embodiments in [reference] Figures 1a - 1c where these features are mentioned.

[0191] Figure 3a is Figure 2d An enlarged perspective view of the area around the adhesive applicator 40 in [reference], where the adhesive applicator 40 is provided in the form of a sprayer 45 here. Obviously, the sprayer 45 can apply the adhesive 20 on the back side 4, for example, on the remaining part 4b described below, as Figure 3b schematically shown, Figure 3b can be Figure 2c An enlarged perspective view of the area around the adhesive applicator 40 in [reference].

[0192] In some embodiments, and as discussed elsewhere in the present disclosure, the non-contact applicator 40 can be a curtain coater 46, which is schematically shown in Figure 3c in operation positioned over the substrate 60, where the substrate 60 is the panel element 1, such as the panel 1'. However, it should be understood that in some embodiments, the substrate 60 onto which the adhesive 20 is applied can be the underlying element. As Figure 3c shown, the adhesive 20 can be stored in the adhesive reservoir 42.

[0193] In some embodiments, Figure 2d the adhesive applicator 40 in

[0194] can be a contact applicator, such as a roll coater 43 or a slot die coater 41. Figures 2b - 2c It should be understood that in the embodiments of Figures 1a - 1c and 3c, after applying the adhesive, the underlying element can be arranged on the panel element 1 by the underlying applicator 31, which can be implemented according to any of the embodiments described in the text, for example, in any one of

[0195] The arranging of the underlying element on the back surface can be carried out in a discontinuous process, such that the underlying applicator 31 operates intermittently. As schematically shown in Figure 3d in any of the embodiments herein, for example, in any one of Figures 1a - 1c and 5f, the underlying applicator 31 can include at least one underlying unit 23a, 23b that can be stored therein. The area and / or shape of the underlying units 23a, 23b can correspond to the area and / or shape of the back surface of the panel element 1 or the panel 1'. The underlying applicator can be adapted to arrange at least one underlying unit on the back surface 4 of the panel element 1 or the panel 1'. The at least one underlying unit can be arranged thereon sequentially, for example, arranged thereon individually. Any known method in the art can be employed, such as the method using the suction cup 55. The control unit 44 can control the operation of the underlying unit.

[0196] Optionally, Figure 2d the system 30 in

[0197] Figures 4a - 4f or 3d can further include a pressing device 35 configured to apply pressure on the underlying element and / or the panel element, where the underlying element and / or the panel element are preferably located at the underlying applicator 31 and / or downstream thereof along the feed path FP'. Figure 1aAn embodiment in any of -c, 2a-2e, 3a-3d, and 5a-5l can be used to implement a method for attaching a lower element 23 such as the lower units 23a, 23b to a panel element 1 or a panel 1' shown in perspective in Figure 4a and Figure 4b .

[0198] The panel 1' and the lower unit 23b can be referred to as a panel assembly. Figure 4c An embodiment of the back surface 4 of the panel 1' is shown in bottom view. The panel 1' includes a groove portion 4a having at least one groove 10 and a remaining portion 4b without any grooves. The remaining portion can be in a horizontal plane HP extending along the back surface. The horizontal plane HP can be parallel to the horizontal plane extending along the front surface 2 of the panel 1'.

[0199] As Figure 4c shown, at least one groove 10 is preferably provided in the inner space of the back surface 4 so as to be spaced apart from a pair of opposite edge portions of the panel, such as opposite short side portions 1c, 1d, and preferably from all edge portions 1a, 1b, 1c, 1d.

[0200] As in the embodiment shown in top view in Figure 4d , the lower element 23 such as the lower units 23a, 23b includes an upper side 21 and an opposite lower side 22 configured to face the panel element or the panel. See Figure 4e . The upper side 21 includes a cover portion 21a and a corresponding remaining portion 21b, which are configured to face the groove portion 4a and the remaining portion 4b and be aligned with the groove portion 4a and the remaining portion 4b when the lower element is attached to the back surface.

[0201] Figure 4e and 4f An embodiment of the panel 1' is schematically shown in side view. The panel 1' includes long side portions 1a, 1b and short side portions 1c, 1d respectively, and the lower unit 23b is attached to the back surface 4 of the panel. For example, the panel and the lower unit can correspond to those disclosed in Figures 4c - 4d . The adhesive 20 contacts at least a part of the remaining portion 4b and the corresponding remaining portion 21b of the lower element, thereby attaching the lower unit to the back surface.

[0202] The panel 1' or generally the panel element 1 can include a layer arrangement structure 3, which includes at least one layer 3a, 3b, 3c. Optionally, the layer arrangement structure 3 can include a lower layer 3c, which can be a backing layer. Thus, at least one groove 10 at least partially penetrates at least one layer 3a, 3b, 3c, such as at least the lower layer 3c.

[0203] Generally, the panel 1' may include a locking system 9 for horizontally and / or vertically locking, preferably by a mechanical locking system, on at least one edge portion, preferably on two opposite edge portions thereof. Figures 4c - 4e A mechanical vertical locking system is shown, which includes tongues 9a, 9a' formed on the long side portions 1a, 1b and the short side portions 1c, 1d, and tongue grooves 9b, 9b'. In addition, Figures 4c - 4e A mechanical horizontal locking system is shown, which includes locking elements 8, 8' provided on the locking bars 6, 6' and locking grooves 14, 14' formed on the long side portions 1a, 1b and the short side portions 1c, 1d. The tongue 9a on the long side portion 1a may be integrally formed with the panel, while the tongue 9a' on the short side portion 1d may be separately formed from the panel and provided in the insertion groove 15. The tongue 9a' may be a displaceable tongue, preferably flexible. Obviously, Figures 4c - 4f the locking system in is exemplary and other locking systems are equally conceivable.

[0204] In some embodiments, the locking system 9 may include at least one connecting element configured to be attached to the back surface 4 of an adjacent panel, for example, at their corners, to connect them to each other. Each connecting element may include an adhesive layer configured to contact the back surface of the adjacent panel. For example, the connecting element may be a tape.

[0205] The panel may extend along a first horizontal direction X and a second horizontal direction Y that may extend parallel to the long side portions 1a, 1b and the short side portions 1c, 1d of the panel, respectively.

[0206] At least one groove 10, for example, the groove length GL along the first horizontal direction X, may be less than the distance between the components of the locking system 9, for example, the distance between the short side portions 1c, 1d. In one embodiment, the groove length GL may be at least 75% of the distance between the components of the locking system 9, for example, at least 85% of this distance, for example, at least 90% of this distance. In a first example, the groove length GL is less than the distance from the inner wall of the locking groove 14' to a vertical plane VP that extends along the edge portion of the panel (for example, the short side portion 1d including the locking bar 6'). The vertical plane VP may be provided along the upper part of the short side portion 1d and may extend perpendicular to the horizontal plane HP. In a second example, the groove length GL is less than the distance from the inner wall of the locking groove 14' to the innermost wall portion of the insertion groove 15 that may be provided on the short side portion 1d including the locking bar 6'.

[0207] However, as Figure 4b shown, it is conceivable that in some embodiments, the panel 1' is not provided with a mechanical locking system. For example, it may be adapted to be loosely arranged on the subfloor, or it may be glued to the subfloor.

[0208] The remaining part 4b may have a thickness Tb that is greater than the thickness Ta of the groove part 4a. Additionally, the main part of the remaining part preferably has a constant thickness, for example, in a region spaced apart from the edge parts 1a - 1d in which a mechanical locking system of the locking system 9, preferably including tongues 9a, 9a' and tongue grooves 9b, 9b' and / or locking elements 8, 8' and locking grooves 14, 14' is formed.

[0209] Preferably, the shape of the end 16 of the groove 10 along its longitudinal direction is curved. For example, such a shape can be obtained when the groove is formed by a rotary cutting device.

[0210] At least one of the layers 3a, 3b, 3c in the layer arrangement structure 3 may each include a polymer-based material, such as a thermoplastic material, and preferably includes a filler. The layers may be (co)-extruded. In this embodiment, the thermoplastic material is PVC, but obviously other thermoplastic materials, such as PE, PP, PET, or ABS, can be used. The filler of any layer may be a mineral material, such as calcium carbonate (CaCO3) or stone material, such as stone powder, or the like. Optionally, at least some of the layers - for example, all of the layers - may contain a plasticizer and / or an additive. For example, the floor panel may be an LVT tile, an SPC panel, an EPC panel, or a WPC panel.

[0211] In other embodiments, the polymer-based material may be a thermosetting material. For example, the panel may include an HDF core board and optionally at least one wood fiber-based layer attached to the core board. For example, the floor panel or wall panel may be a panel or a panel.

[0212] In further embodiments, the panel may be a mineral-based panel, such as a cement panel or a panel containing magnesium oxide and optionally magnesium chloride and / or magnesium sulfate. For example, the panel such as a floor panel or a wall panel may be or may include an MgO panel, a cement board, or a fiber cement board.

[0213] The lower layer elements 23 such as the lower layer units 23a, 23b may include an elastic material. Preferably, the lower layer elements in any of the embodiments disclosed herein, for example, in Figures 1a - 1c , 2d, 3d - 3e, 4a - 4b, 4d - 4f, 5a - 5d, 5f - 5l, and 7a - 7c are foams, such as closed-cell foams, such as IXPE foam, EVA foam, XLPE foam, foam rubber, or PU foam. However, in some embodiments, for example, in any of the said figures, the lower layer element may include cork, such as cork sheets. In still other embodiments, the lower layer element may include a thermosetting resin, such as PU.

[0214] It should be understood that features similar to those described for the panel 1' and the lower unit 23b in Figures 4b - 4f can also be used for the panel element 1 and the lower unit 23a.

[0215] Embodiments of the system 30 and of the method for attaching a lower element, such as a lower unit, to a panel element, such as a panel, are schematically shown in Figures 5a - 5l and are explained in the flow chart (block S10) in Figure 6 . Hereinafter, reference will also be made to the systems described, for example, with respect to Figures 1a - 1c , 2a - 2e and 3a - 3d and to the embodiments of the panel element / panel in Figures 4a - 4f and 7a - 7c.

[0216] Figures 5a - 5d The arrangement of the lower unit 23b on the back side of the panel 1' is schematically shown in a side view. In addition, Figures 5e - 5f the arrangement of the lower unit 23a on the back side of the panel element 1 during a continuous processing operation is shown, whereby the panel element and the lower element are fed along a feed path FP, FP', for example in a feed direction FD, FD'.

[0217] Generally, the method comprises providing a panel element 1 as shown in Figure 5e or a panel 1' as shown in Figure 4c or Figure 5a and a lower element 23 or a lower unit 23a, 23b as shown in Figure 4d or Figure 5a . Figure 5a (block S11), wherein the panel element or the panel comprises a groove portion 4a. In addition, the method comprises applying an adhesive 20 to at least a part of the remaining portion 4b and / or to at least a part of the corresponding remaining portion 21b of the lower element (block S12), see Figure 5b and 5f . The application can also be carried out as in any of the embodiments described, for example, in Figures 1a - 1c , 2a - 2e and 3a - 3c.

[0218] Figure 5fThe adhesive applicator 40 in [[ ]] may include at least one roller coater 43. The adhesive 20 may be applied during the displacement of the panel element 1 and / or the underlying element 23 along the feed paths FP, FP'. Preferably, at least two roller coaters 43 are spaced apart from each other in the transverse direction TD. Thereby, no or substantially no adhesive is applied in at least one cutting portion 12a in which the underlying element is configured to be cut into at least one underlying unit, such as at least two underlying units, and / or no or substantially no adhesive is applied in at least one dividing portion 12b in which the panel element is configured to be divided into at least one panel, such as at least two panels. Also, preferably, no or substantially no adhesive is applied in the back portion 4d in which the locking system 9 of at least one panel 1' is configured to be formed. The divided panels may be substantially similar.

[0219] After applying the adhesive as described above, the underlying element 23 is arranged on the back surface of the panel element or the panel by the underlying applicator 31 (block S13) such that the adhesive contacts the underlying element and the back surface, see for example Figure 5c and 5f . Preferably, the arrangement of the underlying element on the back surface is performed during the displacement of the panel element and / or the underlying element along the feed paths FP and / or FP', as in Figures 1a - 1c and any one of 2d, but it is also conceivable that the arrangement may be performed in a discontinuous processing operation as described for example with respect to Figure 3d .

[0220] In the first case, the panel element is the panel 1' and the underlying element is the underlying unit 23b, where no division and / or cutting is required (block S14), as in the embodiments in Figures 4b - 4d , 5c, 5j, 5l and 7a. Thus, the panel and the underlying unit may have specifications adapted to each other. For example, the panel may be adapted to be loosely set on the underlying floor or it may be glued to the underlying floor. In other examples, the locking system 9, preferably a mechanical locking system including tongues 9a, 9a' and tongue grooves 9b, 9b' and / or locking elements 8, 8' and locking grooves 14, 14', may be pre-formed on at least one edge portion of the panel 1a, 1b, 1c, 1d, such as all edge portions, see for example 4c - 4f, 5d and 7c. However, optionally, the locking system 9, preferably a mechanical locking system including tongues 9a, 9a' and tongue grooves 9b, 9b' and / or locking elements 8, 8' and locking grooves 14, 14', may be post-formed on at least one edge portion of the panel 1a, 1b, 1c, 1d, such as on all edge portions according to known principles in the art (block S15), see for example Figures 4c - 4f, 5d, and 7b-c. Figure 5d Shows a panel 1', which includes a mechanical locking system for horizontal and / or vertical locking, such as a folding mechanical locking system. In any embodiment of the panel with or without a locking system described herein, the outermost horizontal portion and the back surface of the lower layer element can be aligned, for example, along their first horizontal direction X and / or second horizontal direction Y.

[0221] In the second case, and as shown in the embodiments in, for example, Figures 1a - 1c , 2d, 3d, 5g-5l, and 7a-7c, the panel element and / or the lower layer element can be divided and / or cut (block S14). Figures 5g - 5i and Figure 5k The embodiments in show Figure 5f A cross-sectional side view of the panel element 1 along section A-A as shown in.

[0222] In the first example, the attached lower layer element can be processed separately from the panel element or the panel, as shown in the embodiments in Figures 5g - 5j or 7a-7c. As shown in Figures 5g - 5h and 7a-7b, preferably by a cutting tool 52, the lower layer element 23 or the lower layer unit 23a can be cut along at least one cutting portion 12a into at least one lower layer unit 23b (block S21). For example, the cutting tool 52 can be a rotary cutting device, an engraving device, or a knife device. Thereby, the material element 23c can be removed from the lower layer element. For example, the specifications / design of the cut lower layer unit, such as its length along its first horizontal direction X and / or second horizontal direction Y, can be adapted to the specifications of the panel, for example, along its first and / or second horizontal directions. The interior of the lower layer element can be cut as shown in Figures 5g - 5h , and / or the exterior of the lower layer element can be cut as shown in Figures 7a - 7b . Optionally, preferably after the lower layer element has been arranged on the back surface, at least one chamfer 28 can be formed.

[0223] Optionally, and as shown in Figure 5i , the panel element can be divided along at least one dividing portion 12b preferably by a dividing tool 54, for example, including a rotary cutting element such as a circular saw blade, into at least one panel, for example, at least two panels 1' (block S22).

[0224] In the second example, and as shown in the embodiments in Figures 5k - 5l , the division of the panel element and the cutting of the attached lower layer element can be carried out jointly, preferably by the same processing tool 56, which can include the cutting tool 52 and / or the dividing tool 54 (block S24).

[0225] In some embodiments, for example, inFigure 5j , 5l or in 7a, further processing of the panel or the underlying element may not be required, whereby Figure 5j , 5l or 7a may be in their final form. For example, the panel may be adapted to be loosely set or glued to the underlying floor. Optionally, however, as in Figure 7c and also in Figure 5d shown, a locking system 9, preferably a mechanical locking system, may be formed on at least one edge portion of the panels 1a, 1b, 1c, 1d, for example on all edge portions according to known principles in the art (block S23).

[0226] Optionally, the material elements 23c, 4c removed from the underlying element and the panel element during or after cutting and splitting, such as chips, shavings or strips, may be separated from each other (block S25). In some embodiments, the material elements of the adhesive contacting the panel element and / or the underlying element may also be separated. In a first example, the method includes cutting only the underlying element and then splitting the panel element. Thereby, for example, by a separate vacuum device, the removed material elements can be easily separated. In a second example, the method includes performing cutting and splitting in the same operation, which method optionally further includes forming the locking system 9. The separation of the material elements can then be based on at least one property of the underlying element and the panel element and optionally the adhesive. The separation can be implemented by the separation device 37 in the system 30, which is schematically shown in Figure 5k . The separation device 37 can be configured to screen or sieve the material elements, or it can use gravitational separation of the material elements, such as specific gravity separation. For example, density separation or cyclone separation can be employed. In any of the above first and second examples, optionally, no or substantially no adhesive is applied in the cut portion 12a and / or the split portion 12b.

[0227] In some embodiments, during or after forming the locking system 9 on the panel element, the material elements 23c, 4c removed from the underlying element and the panel element can be separated from each other. At least a part of the locking system can be formed by removing material from the back portion 4d, see Figure 7a .

[0228] Figures 8a - 8f and 9a - 9b show in a bottom view an embodiment of a panel 1' including the applied adhesive 20.

[0229] Generally, for example, in Figures 1a - 1cIn any one of 2a - 2e, 3a - 3e, 5b, 5f, 8a - 8f, and 9a - 9b, the adhesive can be applied continuously or intermittently along the feed paths FP, FP' - for example, along the feed directions FD, FD' - on at least a part of the panel element 1 and / or the underlying element 23. Thus, the applied adhesive can extend continuously or discontinuously along the first horizontal direction X and / or the second horizontal direction Y.

[0230] Any continuous or intermittent application of the adhesives disclosed herein can be, for example, a wide - area application as shown in the embodiments of Figure 5f 、 8a 、8e - 8f, and 9a - b and / or a linear application as shown in the embodiments of Figures 8b - 8e and 9b. In Figure 8a 、 8e -8f, and 9a - 9b, at least a part of the adhesive 20 is applied on substantially the entire width of the remaining part 4b along the second horizontal direction Y between the long - side parts 1a, 1b. Figure 8a and 9a show embodiments in which the adhesive is applied substantially on the entire remaining part 4b. In Figure 5f , the adhesive is applied as at least two, for example three, wide - area applications, which can be spaced apart from each other as described above. In Figures 8b - 8f and 9b, the adhesive is applied along the first horizontal X and / or the second horizontal direction Y on at least a part of the width of the remaining part 4b, and thus preferably between the short - side parts 1c, 1d and / or between the long - side parts 1a, 1b.

[0231] In Figures 8a - 8f and 9a - 9b, the adhesive 20 is applied in the peripheral part 5 of the back 4. As shown by the dashed line in Figure 8b , the peripheral parts 5, 5' of the back 4 or the upper side 21 can be positioned within a distance of 10%, preferably 5%, of the total length LX, LY of the panel element or the underlying element from the outermost horizontal part of the back or the upper side. The adhesive can be applied along the long - side parts 1a, 1b and / or along the short - side parts 1c, 1d.

[0232] Figures 8a - 8c , 8e - 8f, and 9b show that the application can be a linear application or a wide - area application, whereby the adhesive is applied along, i.e., parallel to, the first horizontal direction X and / or the second horizontal direction Y. Figure 8d and 9a show that the application can be a linear application or a wide - area application, respectively, whereby the adhesive is applied at an angle with respect to the first horizontal direction X and / or the second horizontal direction Y.

[0233] In, for example, as in Figure 8c and9a In any of the embodiments disclosed herein as shown in -9b, the adhesive 20 may be applied to the remaining portion 4b and / or the corresponding remaining portion 21b in a pattern arrangement 26. Figure 9a The embodiment in shows the adhesive provided on the remaining portion 4b, wherein the basic application design 27 of the adhesive in the pattern arrangement 26 is set in the form of a grid.

[0234] The pattern arrangement may be, for example Figure 8c or Figure 9a the main pattern 24 in. As Figure 9b shown, the pattern arrangement 26 may further include at least one additional pattern, such as the secondary pattern 25. The secondary pattern may include at least two main patterns 24 that may be spaced apart from each other, for example, along the first horizontal direction X and / or the second horizontal direction Y. In Figure 9b , the main patterns 24 are spaced apart from each other along the first horizontal direction X. Optionally, additional adhesive 20 may be applied between the main patterns, which may be applied, for example, by line application in the peripheral portions 5, 5' as described above. Figure 9b In, the basic application design 27 of the adhesive forms a circle. However, as Figure 9d the embodiment in shows, other basic application designs are equally conceivable, such as an ellipse, or a polygon, such as a triangle, a square, or a star, etc.

[0235] Generally, and as Figure 8f and 9b shown, the groove portion 4a may include at least two groove arrangement structures 11, each groove arrangement structure including at least one groove 10, preferably a plurality of grooves. The grooves may be formed discontinuously on the back surface 4 and their longitudinal extensions may be parallel to the long side portions 1a, 1b. The extensions of the grooves in each groove arrangement structure, such as the longitudinal extensions, are preferably parallel to each other. The groove arrangement structures may be spaced apart from each other in the first horizontal direction X and / or the second horizontal direction Y of the plate element or panel. The groove arrangement structures may be spaced apart by a separating portion 13 provided on the back surface 4, and the separating portion 13 preferably extends continuously, for example, along the second horizontal direction Y between the long side portions 1a, 1b. For example, the separating portion may include a rectangular portion.

[0236] As Figure 8f shown, the adhesive 20 may be applied, preferably controlled to be applied, for example, along the first horizontal direction X between the groove arrangement structures 11. The adhesive may be applied in the separating portion 13, for example, covering the entire separating portion. Optionally, and as Figure 8f shown, the adhesive may also be applied, for example, along the second horizontal direction Y between the grooves 10 of the groove arrangement structures 11. For example, the adhesive may be applied between the ends 16 of the grooves 10.

[0237] For example, the adhesive 20 provided with the main pattern 24 as in Figure 9b can be applied, for example, along the first horizontal direction X between the groove arrangements 11.

[0238] Generally, the pattern arrangement 26 can be applied by contact application - for example, by a slot die coater 41 or by a roll coater 43 - or by non-contact application - for example, by a sprayer 45 or a curtain coater 46. For example, the Figures 1a - 1c embodiments in 2a - 2e, 3a - 3d and 5a - 5l elsewhere in the present disclosure can be used to achieve contact application or non-contact application.

[0239] In addition, Figure 9c and 9e the embodiments in show an engraved roll coater 43 in a top view and a perspective view, which includes a plurality of structural elements 47, such as indentations and / or protrusions. Figure 9c and 9e the structural elements of the roll coater in can respectively correspond to Figure 9a the pattern arrangement 26 in Figure 9b and the main pattern 24 in Figure 9c The structural elements 47 in are arranged along the circumference of the roll coater, while Figure 9e the structural elements 47 in are arranged in groups 48, and each group is preferably spaced apart from each other along the circumference of the roll coater. Obviously, Figure 9c the adhesive applicator 40 in 9e can be connected to an adhesive reservoir 42 as described elsewhere herein. Generally, the adhesive applicator can include at least one roll coater, whereby Figure 9c the roll coater in 9e can be a coating roll 43a, see the Figure 2b embodiment in

[0240] Figure 9c and 9e the roll coater embodiments in can achieve continuous or intermittent application of the adhesive. Continuous application can be implemented as in, for example, Figure 2b For example, the roll coater 43 and the conveying device 50 can be fixedly installed in a frame 32, for example. In addition, as shown by the dashed arrows in Figure 2b , generally, intermittent application can be implemented by bringing the roll coater 43 into contact with and separating from the plate element 1 and / or the underlying element 23 while the roll coater 43 is displaced along the feed paths FP, FP'. In the first example, the roll coater 43 can be displaceably installed in a frame 32, for example. In the second example, the conveying device 50 can be movably installed in a frame 32, for example.

[0241] Generally, the adhesive can be applied by transfer application. Figure 9fThe embodiment in [reference] shows a part of an adhesive applicator 40 in a perspective view. The adhesive applicator 40 includes an adhesive unit 49 in the form of a slot die coater 41 and a transfer roller 49' that can intermittently and / or apply the adhesive 20 on the substrate 60 in a pattern arrangement 26. The substrate 60 can be conveyed along a feed path FP, FP' in a feed direction FD, FD'. As described above, the substrate 60 can be a panel element 1, such as a panel 1', or an underlying element 23, such as underlying units 23a, 23b. The slot die coater 41 can apply the adhesive 20 along its circumferential and longitudinal extension dimension L on a roller coater 43, for example, intermittently and / or by applying the adhesive in a pattern arrangement and preferably during its rotation. For example, it can be achieved by Figure 9f the adhesive applicator 40 in [reference] to obtain, for example, Figure 8f and Figure 10b the intermittent application of the adhesive shown in [reference]. In addition, it can be achieved by Figure 9f the adhesive applicator 40 in [reference] to obtain, for example, Figure 8b , 8e and the application of the adhesive shown in 10e - 10f. In some embodiments, Figure 9f the adhesive coating on the substrate 60 in [reference] can be discontinuous in the direction TD or TD'. For example, the slot die coater can be used in combination with at least one mask 40a shown by a dashed line in Figure 9f [reference].

[0242] It should be understood that the application of the adhesive on the panel element - for example, as described in any one of Figures 8a - 8f [references] that describe wide - area application, linear application, peripheral application, pattern arrangement, etc. - can equally be conceived as the application of the adhesive on the corresponding remaining part 21b of the underlying element. An example of such an application is shown in Figures 10a - 10b [reference], Figures 10a - 10b which shows an embodiment of the underlying element 23b in a top view. These applications are respectively similar to Figure 8a and Figure 8f the applications shown in [reference]. Preferably, the adhesive 20 is not applied in the cover part 21a. However, in some embodiments herein, the main part of the cover part (e.g., more than 50%) can be free of adhesive.

[0243] As shown in a bottom view in the embodiment of Figure 10c [reference], it should be noted that in some embodiments, the longitudinal extension of the groove 10 can be parallel to the short - side parts 1c, 1d. Figure 10d The embodiment in [reference] shows in a top view a lower - layer unit 23b configured to be attached to Figure 10c the panel 1' in [reference], where the cover part 21a and the corresponding remaining part 21b are indicated. Figure 10c and10d It is shown that the adhesive 20 is applied respectively on substantially the entire remaining part 4b and / or the corresponding remaining part 21b. Preferably, the adhesive is not applied in the groove part 4a or the cover part 21a.

[0244] In some embodiments, as Figure 9g and 9h shown, the lower layer element 23 can be formed discontinuously, for example, the lower layer units 23a, 23b, which include perforations 21d and / or at least one slot 21e. At least one slot 21e can be configured to be aligned with the groove part 4a of the panel. Thus, less adhesive may be required for attachment. Other features may be similar to those described elsewhere herein, for example, as Figure 3e 、 4a shown in -4f, 5a - 5l, 7a - 7d, 8a - 8f, 9a - 9b and 10a - 10f.

[0245] The method may include controlling the application of the adhesive 20 such that no or substantially no adhesive is applied in at least one cutting part 12a and / or at least one dividing part 12b. Moreover, the method may include controlling the application of the adhesive such that no or substantially no adhesive is applied in the back part 4d in which the locking system 9 of at least one panel 1' is configured to be formed, and / or no or substantially no adhesive is applied in the upper side part 21c of at least one lower layer unit configured to contact the back part 4d. An example of such a back part 4d is shown in the embodiments of Figure 7a .

[0246] Figure 10e One embodiment of the panel element 1 including the applied adhesive 20 is shown in a bottom view and the lower layer unit 23a is shown in a side view. Moreover, Figure 10f One embodiment of the lower layer unit 23b including the applied adhesive 20 is shown in a top view and the panel element 1 is shown in a side view. In each of these embodiments, no or substantially no adhesive is applied in at least one cutting part 12a and / or at least one dividing part 12b. For example, Figure 10e the adhesive in or 10f can be applied by a slot die coater 41 or a sprayer 45 or even by an engraved roll coater 43. In Figures 10e - 10f , the lower layer unit 23a or the lower layer unit 23b can be attached to the corresponding panel element 1 or panel 1'.

[0247] As Figure 10e shown, the adhesive can be applied in the peripheral part 7 of at least two panels 1', and the panel element 1 is configured to be divided into the at least two panels 1'. Moreover, Figure 10fIt is shown that the adhesive can be applied in the peripheral part 7' of at least two lower-layer units 23b, and the lower-layer element 23a is configured to be cut into the at least two lower-layer units 23b. As Figure 10e and 10f shown for the rightmost panel 1' and the lower-layer unit 23b, the peripheral parts 7, 7' can be defined similarly to the above-mentioned peripheral parts 5, 5'. For example, in any of these embodiments, the adhesive can be applied in a line-like application manner, and this line-like application extends, for example, along the first horizontal direction X of the panel 1' or the lower-layer unit 23b, such as along the long side part. Optionally, as Figure 10e shown, the adhesive 20 can also be applied in a line-like application manner, and this line-like application extends, for example, along the second horizontal direction Y of the panel 1' or the lower-layer unit 23b, such as along the short side part. Preferably, no or substantially no adhesive is applied in at least one cutting part 12a and / or at least one dividing part 12b. The adhesive is preferably applied in the peripheral parts 5, 5'.

[0248] Generally, it is possible to control the adhesive to be applied only on the remaining part 4b and / or the residual part 21b. The method can include an action of controlling the application of the adhesive 20 based on the characteristics of at least one groove 10. For example, the control unit 44 can control this application. The adhesive can be applied by spraying, curtain coating, slot die coating or roll coating. The characteristics can be at least one selected from the group consisting of the shape, extension, and position of at least one groove 10 or at least one groove arrangement structure 11 in the first horizontal direction X and / or the second horizontal direction Y, and the distance between at least one pair of grooves or between a pair of groove arrangement structures along the first and / or second horizontal direction. The control can include controlling the positioning of the adhesive on the plate element and / or the lower-layer element and optionally the amount of the adhesive.

[0249] In any of the embodiments described herein, and as Figures 1a - 1b schematically shown, the control unit 44 can retrieve data about the characteristics from the data storage unit 57, and this data storage unit 57 can store predetermined data and / or collected data. For simplicity, the data storage unit 57 is usually hidden in the figure. For example, the data can be obtained or collected by scanning the back surface 4 with a scanner 58 preferably connected to the data storage unit 57. The scanner 58 can include a horizontal scanning unit 58a and / or a vertical scanning unit 58b, which are configured to determine data about the grooves along at least one direction X, Y, Z, such as along at least one horizontal direction X, Y and / or along the vertical direction Z. The scanning device 58 can include an image sensor, such as a digital camera and / or a laser triangulation device. For example, the scanner 58 optionally including the horizontal scanning unit 58a and / or the vertical scanning unit 58b can be provided in a visual inspection system.

[0250] In some embodiments, data regarding the feature, which may be predetermined data and / or collected data, may determine the position of the adhesive applicator 40, such as the roll coater 43 or the slot die coater 41, relative to the panel element 1 and / or the position of the underlying element 23.

[0251] The application of the adhesive 20 may be controlled to be between at least one groove arrangement 11 and / or the discontinuous grooves 10, for example as Figure 9b shown.

[0252] Generally, the adhesive 20 may be post-treated by a post-treatment device 34 such as the drying device and / or the radiation device described above. Alternatively or additionally, the method may further include post-heating the adhesive by a post-heating device 36 and / or exposing the adhesive to moisture by a moisture regulator 39.

[0253] The method may further include applying pressure to the adhesive 20, preferably during the curing or hardening of the adhesive. For example, a pressing device 35 may be used, such as the Figure 1a and 3d pressing device described.

[0254] In some embodiments, the adhesive 20 may be pre-applied to the underlying element 23. For example, the underlying element may be conveyed to the system 30 together with the pre-applied adhesive. In such embodiments, for example, in any of the embodiments in Figures 1a - 1c 2d, 3d, 4a-4f, 5a-5l, 7a-7c, the applicator of the adhesive applicator 40 may become redundant, but other features may be the same. However, it should be noted that in any of the embodiments described herein where the application of the adhesive on the panel element 1, 1' or the underlying element 23, 23a, 23b is described, for example, in 8a-8f and 9a-9b, 9d, 10a-10f, the pre-applied adhesive 20 may be embodied. For example, the adhesive may be applied in a line, in a wide width, in a pattern arrangement 26, etc.

[0255] As Figure 7d schematically shown, the underlying element with the pre-applied adhesive may be provided with a release liner 29, such as a release film. The release liner may be removed, for example, by a liner removal device 38 provided in the system 30 before the underlying element is arranged on the back surface 4. In some embodiments, the release liner 29 may be removed during a continuous processing operation, for example, when the panel element and / or the underlying element are fed along a feed path FP, FP', for example, along a feed direction FD, FD'.

[0256] Figure 3e The embodiments in illustrate any of the embodiments herein, for example Figures 1a - 1c、in any of the embodiments of 2a - 2e, 3a - 3d, 4a - 4f, 5a - 5l, 7a - 7d, 8a - 8f, 9a - 9b, 10c, and 10e - 10f, the remainder 4b may include surface roughness, such as including peaks 4e and valleys 4f. For example, the surface roughness may be provided by embossing the back surface 4. The peaks may be in the horizontal plane HP. The adhesive 20 for attaching the lower layer element 23 to the panel element 1 may be provided on the peaks 4e, preferably such that no or substantially no adhesive is applied in the valleys 4f.

[0257] The inventive concept has been mainly described with reference to several embodiments above. However, as will be readily understood by those skilled in the art, within the scope of the inventive concept as defined in the appended patent claims and the items in the following embodiments section, other embodiments in addition to the embodiments disclosed above are equally possible. For example, it is clear that: for example Figures 1a - 1c 、in any of the embodiments of 2a - 2e, 3c - 3e, 4a - 4b, 5a - 5l, 7a - 7d, 8a - 8f, and 9a - 9b, the panel element or panel may include a layer arrangement structure 3, which includes at least one layer 3a, 3b, 3c, similar to the Figures 4a - 4f discussion related to the embodiments in. At least one layer in the layer arrangement structure 3 may each include a polymer - based material, such as a thermoplastic material or a thermosetting material, and preferably includes fillers. Additionally, it is obvious that any system described herein, such as Figures 1a - 1c 、in any of 2a - 2e, 3a - 3d, 5a - 5l, 7a - 7c, and 9c - 9f, the system may include a post - treatment device 34, such as a drying device, a radiation device, or a moisture regulator 39, or a post - heating device 36. Optionally, the system may include a separation device 37. Finally, and as described above, it is obvious that in some embodiments, the panel 1’, such as Figures 1a - 1c 、in any of 2b - 2d, 3c - 3e, 4a - 4b, 5a - 5l, 7a - 7c, 8a - 8f, 9a - 9b, 10c, and 10e - 10f, the panel 1’ may alternatively be a building panel, a wall panel, a ceiling panel, or a furniture panel. However, it is obvious that the panel 1’ in these embodiments may include a locking system different from that shown in the figures, or it may even have no locking system.

[0258] Example 1

[0259] Apply a layer of 20 g / m with a roller coater 2Reactive PUR hot melt coating P. The material PR-6620 is applied to the back surface of an SPC panel provided with a plurality of grooves. An EVA foam is arranged on the back surface of the panel such that the hot adhesive contacts the foam and the back surface. Subsequently, the panel is pressed in a calender. The line speed is set to 30 m / min, and the calendering pressure is set to 3 Bar. The adhesive is applied at an application temperature of 110 °C, an ambient temperature of 25 °C, and an RH value of 55%.

[0260] Example 2

[0261] A layer of 20 g / m is applied with a sprayer 2 Reactive PUR hot melt KLEIBERIT 711.2.00 is applied to the back surface of an LVT tile provided with a plurality of grooves. An IXPE foam is arranged on the back surface of the tile such that the hot adhesive contacts the foam and the back surface. Subsequently, the tile is pressed in a calender. The line speed is set to 15 m / min and the calendering pressure is set to 3 Bar. The adhesive is applied intermittently in a pattern arrangement at an application temperature of 120 °C, an ambient temperature of 25 °C, and an RH value of 55%.

[0262] Embodiment

[0263] Some further aspects of the inventive concept are provided below. Embodiments, examples, etc. of these aspects are to a large extent similar to those described above, and thus are described in detail with reference to the above.

[0264] Item 1. A method for attaching a lower layer element (23) such as a lower layer unit (23a; 23b) to a panel element (1) such as a panel (1'), comprising:

[0265] Providing a panel element, wherein the back surface (4) of the panel element comprises a groove portion (4a) and a remaining portion (4b), the groove portion comprising at least one groove (10),

[0266] Providing the lower layer element (23),

[0267] Applying an adhesive (20) to at least a part of the remaining portion (4b) and / or at least a part of the corresponding remaining portion (21b) of the lower layer element, and

[0268] Arranging the lower layer element on the back surface of the panel element such that the adhesive contacts the lower layer element and the back surface.

[0269] Item 2. The method according to Item 1, wherein the adhesive is applied during displacement of the panel element and / or the lower layer element along a feed path (FP; FP').

[0270] Item 3. The method according to Item 1 or 2, wherein arranging the lower layer element on the back surface is performed during the displacement of the plate element and / or the lower layer element along the feed path (FP; FP').

[0271] Item 4. The method according to any one of the preceding items, wherein the adhesive is applied at least on the peripheral portion (5) of the back surface and / or the peripheral portion (5') of the upper side of the lower layer element, and any one or both of the peripheral portions preferably extend along the short side portions (1c, 1d) and / or the long side portions (1a, 1b) of the plate element and / or the lower layer element.

[0272] Item 5. The method according to Item 4, wherein the peripheral portion of the plate element includes at least one panel, for example, the peripheral portion (7) of at least two panels, and the plate element is configured to be divided into the panels, and / or the peripheral portion of the lower layer element includes at least one lower layer unit, for example, the peripheral portion (7') of two lower layer units, and the lower layer element is configured to be cut into the lower layer units.

[0273] Item 6. The method according to any one of the preceding items, wherein the method further includes controlling the application of the adhesive based on the characteristics of the at least one groove, and the control preferably causes the adhesive to be selectively applied, for example, applied on the remaining portion and / or the corresponding residual portion.

[0274] Item 7. The method according to Item 6, further including retrieving data on the characteristics of the at least one groove to control the application of the adhesive.

[0275] Item 8. The method according to any one of the preceding items, wherein the adhesive is applied by contact application, for example, by slot die coating or by roll coating, and / or by non-contact application, for example, by spraying or curtain coating.

[0276] Item 9. The method according to any one of the preceding items, wherein the adhesive is applied continuously or intermittently, for example, along the feed path (FP; FP') of the plate element and / or the lower layer element.

[0277] Item 10. The method according to any one of the preceding items, wherein the adhesive is applied in a pattern arrangement (26).

[0278] Item 11. The method according to any one of the preceding items, wherein the thickness (Tb) of the remaining portion is greater than the thickness (Ta) of the groove portion, and the main portion of the remaining portion preferably has a constant thickness.

[0279] Item 12. The method according to any one of the preceding items, wherein at least two grooves are formed discontinuously, and the application of the adhesive comprises: for example, applying the adhesive between the discontinuous grooves along a first horizontal direction (X) and / or a second horizontal direction (Y) of the plate element.

[0280] Item 13. The method according to any one of the preceding items, wherein the plate element comprises at least one layer (3a, 3b, 3c), and the at least one groove at least partially penetrates the at least one layer, for example, at least partially penetrates at least one lower layer (3c).

[0281] Item 14. The method according to item 13, wherein each of the at least one layer optionally including an upper layer (3a) and / or a lower layer (3c) comprises a polymer-based material, preferably a thermoplastic material or a thermosetting material, and preferably further comprises a filler.

[0282] Item 15. The method according to any one of the preceding items, further comprising:

[0283] Cutting the lower layer element (23) into at least one lower layer unit (23a; 23b) along at least one cutting part (12a).

[0284] Item 16. The method according to any one of the preceding items, further comprising:

[0285] Dividing the plate element (1) into at least one panel (1'), for example, at least two panels, along at least one dividing part (12b).

[0286] Item 17. The method according to item 16, wherein the plate element is divided after the operation of arranging the lower layer element on the back surface.

[0287] Item 18. The method according to any one of the preceding items, further comprising controlling the application of the adhesive such that no or substantially no adhesive is applied to the back surface part (4d) of the plate element and / or the upper side part (21c) of the lower layer element, and the upper side part is configured to be further processed, for example, by cutting, dividing or forming a locking system.

[0288] Item 19. The method according to any one of the preceding items, further controlling the application of the adhesive such that no or substantially no adhesive is applied in at least one cutting part (12a) and / or at least one dividing part (12b).

[0289] Item 20. The method according to any one of the preceding items, further comprising controlling the application of the adhesive such that no or substantially no adhesive is applied in the following parts:

[0290] A rear part (4d), for example a locking system (9) of at least one panel (1') is configured to be formed in the rear part (4d), and / or

[0291] an upper side part (21c) of the at least one lower element (23a; 23b), the upper side part being configured to be arranged along the rear part (4d), for example in contact with the rear part (4d).

[0292] Item 21. The method according to any one of the preceding items, further comprising separating, during or after processing the panel element and the lower element, material elements removed from the lower element and the panel element, such as chips, shavings or strips, for example by separating the material elements based on at least one property of the lower element and the panel element respectively.

[0293] Item 22. The method according to item 21, wherein the processing includes cutting the lower element (23) into at least one lower unit (23a; 23b) and dividing the panel element into at least one panel and / or forming a locking system (9) on the panel element.

[0294] Item 23. The method according to any one of the preceding items, wherein the adhesive is a hot melt adhesive.

[0295] Item 24. The method according to any one of the preceding items, further comprising drying the adhesive and / or exposing the adhesive to radiation, such as infrared or ultraviolet radiation.

[0296] Item 25. The method according to any one of the preceding items, further comprising post-heating the adhesive, that is, heating the adhesive when or after the adhesive is applied to the back surface.

[0297] Item 26. The method according to any one of the preceding items, further comprising applying pressure to the lower element and / or the panel element, preferably during the curing or hardening of the adhesive.

[0298] Item 27. The method according to any one of the preceding items, wherein the lower element is a foam such as a closed-cell foam, for example IXPE foam, IXPP foam, EVA foam, XLPO foam, XLPE foam, foam rubber or PU, PO, PE or PS foam, or the lower element is cork.

[0299] Item 28. The method according to any one of the preceding items, wherein the panel element is a panel (1'), and the method further comprises forming a locking system (9) for horizontal and / or vertical locking, preferably a mechanical locking system, on at least one edge part of the panel, preferably on all edge parts (1a, 1b; 1c, 1d).

[0300] Item 29. The method according to any one of the preceding items, wherein the panel is a floor panel or a wall panel.

[0301] Item 30. A panel element (1), such as a panel (1’), obtainable by a method according to any one of the preceding items 1 - 29.

[0302] Item 31. A system (30) for attaching a sub - element (23), such as a sub - unit (23a; 23b), to a panel element (1), such as a panel (1’), comprising:

[0303] An adhesive applicator (40), and

[0304] A sub - element applicator (31).

[0305] Item 32. A panel assembly comprising a panel (1’) and a sub - unit (23b),

[0306] wherein the back (4) of the panel comprises a groove portion (4a) and a remaining portion (4b), the groove portion comprising at least one groove (10), and

[0307] wherein the sub - unit (23b) is attached to the back of the panel by an adhesive (20) contacting at least a part of the remaining portion and a corresponding remaining part (21b) of the sub - unit.

[0308] Item 33. The panel assembly according to item 32, wherein the thickness (Tb) of the remaining portion is greater than the thickness (Ta) of the groove portion, and preferably a major part of the remaining portion has a constant thickness.

[0309] Item 34. The panel assembly according to item 32 or 33, wherein the adhesive is applied in a pattern arrangement (26).

[0310] Item 35. The panel assembly according to any one of the preceding items 32 - 34, wherein at least two grooves are formed discontinuously, and the adhesive is arranged, for example, along a first horizontal direction (X) and / or a second horizontal direction (Y) of the panel between the discontinuous grooves.

[0311] Item 36. The panel assembly according to any one of the preceding items 32 - 35, wherein the panel comprises at least one layer (3a, 3b, 3c), and the at least one groove at least partially penetrates the at least one layer, for example, at least partially penetrates at least one lower layer (3c).

[0312] Item 37. The panel assembly according to item 36, wherein each of the at least one layer, optionally comprising an upper layer (3a) and / or a lower layer (3c), comprises a polymer - based material, such as a thermoplastic material, and preferably comprises a filler.

[0313] Item 38. A method for attaching a lower element (23) such as a lower unit (23a; 23b) to a panel element (1) such as a panel (1'), comprising:

[0314] providing a panel element, wherein the back surface (4) of the panel element comprises a groove portion (4a) and a remaining portion (4b), the groove portion comprising at least one groove (10),

[0315] providing a lower element (23) comprising a pre-applied adhesive (20),

[0316] and

[0317] positioning the lower element on the back surface of the panel element such that the adhesive contacts the lower element and the back surface.

[0318] Item 39. The method according to item 38, wherein the adhesive (20) is applied to at least a part of the corresponding remaining portion (21b) of the lower element, for example only to the corresponding remaining portion.

[0319] Item 40. The method according to item 38 or 39, further comprising synchronizing the position of the lower element with the position of the panel element such that the lower element becomes aligned with the panel element, preferably such that the cover portion (21a) is aligned with the groove portion and the corresponding remaining portion (21b) is aligned with the remaining portion.

[0320] Item 41. The method according to any one of the preceding items 38 to 40, wherein the lower element is provided with a peelable liner (29), such as a peelable film, and the method further comprises removing the peelable liner before positioning the lower element on the back surface.

[0321] Item 42. The method according to any one of the preceding items 38 to 41, wherein no or substantially no pre-applied adhesive is applied to the upper side portion (21c) of the lower element configured for further processing, for example by cutting or forming a locking system.

[0322] Item 43. The method according to any one of the preceding items 38 to 42, wherein no or substantially no pre-applied adhesive is applied in at least one cut portion (12a).

[0323] Item 44. The method according to any one of the preceding items 38 to 43, wherein no or substantially no pre-applied adhesive is applied to the upper side portion (21c) of the at least one lower layer unit (23a; 23b), the upper side portion being configured to be arranged along a back side portion (4d) - for example, a locking system (9) of at least one panel (1') is formed in the back side portion - and to contact, for example, the back side portion (4d).

[0324] Item 45. The method according to any one of the preceding items 38 to 44 and further according to any one of the preceding items 3 - 5, 10 - 17, 21 - 29.

Claims

1. A panel assembly comprising a weight-reduced panel (1') and a lower unit (23a; 23b), wherein the panel (1') is a floor panel or a wall panel, Among them, The back surface (4) of the panel (1') includes a groove portion (4a) and a remaining portion (4b), the groove portion (4a) includes at least one groove (10) and the remaining portion (4b) is in a horizontal plane (HP) extending along the back surface (4) of the panel (1'), wherein the lower unit (23a; 23b) is attached to the back surface (4) of the panel (1') by an adhesive (20), the adhesive (20) contacting at least a part of the remaining portion (4b) and a corresponding remaining portion (21b) of the lower unit (23a; 23b), wherein the adhesive (20) is applied at least on the peripheral portion (5) of the back surface (4) and / or the peripheral portion (5') of the upper side (21) of the lower unit (23a; 23b), The upper side (21) includes a cover portion (21a) and the corresponding remaining portion (21b), wherein the cover portion (21a) is configured to face the groove portion (4a) and align with the groove portion (4a) when the lower unit (23a; 23b) is attached to the back surface (4), the corresponding remaining portion (21b) is configured to face the remaining portion (4b) and align with the remaining portion (4b) when the lower unit (23a; 23b) is attached to the back surface (4), and wherein the lower unit (23a; 23b) is a foam or cork sheet, wherein the panel (1') includes at least one layer (3a, 3b, 3c), each of the at least one layer contains a thermoplastic material, and the at least one groove (10) at least partially penetrates the at least one layer, wherein the groove portion (4a) is separated from the peripheral portion (5) of the back surface (4), and / or the cover portion (21a) is separated from the peripheral portion (5') of the upper side (21).

2. The panel assembly according to claim 1, wherein, The thickness (Tb) of the remaining portion (4b) is greater than the thickness (Ta) of the groove portion (4a), and the main part of the remaining portion (4b) preferably has a constant thickness.

3. The panel assembly according to claim 1 or 2, wherein, Any one or both of the peripheral portions (5; 5') extend along the short side portions (1c, 1d) and / or the long side portions (1a, 1b) of the panel (1') and / or the lower unit (23a; 23b).

4. The panel assembly according to claim 1 or 2, wherein The at least one groove (10) is provided inside the back surface (4) so as to be spaced apart from a pair of opposite edge portions (1c, 1d) of the panel (1').

5. The panel assembly according to claim 1 or 2, wherein, The at least one groove (10) is provided inside the back surface (4) so as to be spaced apart from all the edge portions (1a, 1b, 1c, 1d) of the panel (1').

6. The panel assembly according to claim 1 or 2, wherein The adhesive is applied in a pattern arrangement (26).

7. The panel assembly according to claim 1 or 2, wherein At least two grooves are formed discontinuously, and the adhesive is provided between the discontinuous grooves along the first horizontal direction (X) and / or the second horizontal direction (Y) of the panel (1').

8. The panel assembly according to claim 7, wherein, The at least one layer (3a, 3b, 3c) includes an upper layer (3a) and / or a lower layer (3c).

9. The panel assembly according to claim 1 or 2, wherein, Each of the at least one layer (3a, 3b, 3c) contains a filler.

10. The panel assembly according to claim 1 or 2, wherein The at least one groove (10) at least partially penetrates the lower layer (3c) of the at least one layer (3a, 3b, 3c).

11. The panel assembly according to claim 1 or 2, wherein, The panel (1’) includes a mechanical locking system for horizontal and / or vertical locking.

12. The panel assembly according to claim 11, wherein, The mechanical locking system includes tongues (9a, 9a’) and tongue grooves (9b, 9b’), which are configured to cooperate with the tongue grooves and tongues provided on adjacent panels, respectively.

13. The panel assembly according to claim 1 or 2, wherein, The lower layer units (23a; 23b) are formed discontinuously and include perforations (21d) and / or at least one slot (21e).

14. The panel assembly according to claim 1 or 2, wherein, The thickness of the lower layer units (23a; 23b) is between 0.5 mm and 4 mm, and the thickness of the panel (1’) is between 2 mm and 10 mm.

15. The panel assembly according to claim 1 or 2, wherein, The depth of the at least one groove (10) is greater than 2 mm.

16. The panel assembly according to claim 1 or 2, wherein The lower layer units (23a; 23b) are closed-cell foams.

17. The panel assembly according to claim 1 or 2, wherein, The lower layer units (23a; 23b) are open-cell foams.

18. The panel assembly according to claim 1 or 2, wherein, The lower layer units (23a; 23b) are pre-mounted on the panel (1’).

19. The panel assembly according to claim 1 or 2, wherein, The remaining portion (4b) includes a surface roughness, which includes peaks (4e) and valleys (4f), and the peaks vertically extend less than 0.5 mm from the valleys.

Images