METHOD AND SYSTEM FOR ATTACHING AN UNDERLAY ELEMENT TO A BOARD ELEMENT AND AN ASSOCIATED BOARD ELEMENT

Abstract

A method for attaching an underlay element to a weight-reduced board element. The method includes providing a board element and an underlay element, wherein a rear side of the board element includes a groove portion and a remaining portion. The groove portion includes at least one groove. An adhesive is applied on at least a portion of the remaining portion and/or on at least a portion of a corresponding residual portion of the underlay element, and the underlay element is arranged on the rear side of the board element, such that the adhesive contacts the underlay element and the rear side.

Claims

1. A method for attaching an underlay element, to a weight-reduced board element comprising at least one groove, the board element being a panel per se or the board element being dividable into at least one panel, wherein each panel is a floor panel or a wall panel, the method comprising: providing a board element, wherein a rear side of the board element comprises a groove portion and a remaining portion, said groove portion comprising said at least one groove and said remaining portion being provided in a horizontal plane (HP) extending along the rear side of the board element, providing the underlay element, applying an adhesive on at least a portion of said remaining portion and/or on at least a portion of a corresponding residual portion of the underlay element, and arranging the underlay element on the rear side of the board element, such that the adhesive contacts the underlay element and the rear side, wherein the board element comprises at least one layer, said at least one layer each comprising a thermoplastic material, and wherein the at least one groove at least partly penetrates the at least one layer, and wherein the method further comprises controlling said applying of the adhesive based on a characteristic of the at least one groove, wherein the controlling results in adhesive being selectively applied.

2. The method according to claim 1, wherein the characteristic is a shape of the at least one groove and/or an extension of the at least one groove in a first (X) and/or a second (Y) horizontal direction of the board element.

3. The method according to claim 1, wherein the characteristic is: a position of the at least one groove in the rear side and/or a distance between at least one pair of grooves in the first (X) and/or the second (Y) horizontal direction, or a distance between at least one pair of groove arrangements in the first (X) and/or the second (Y) horizontal direction, each groove arrangement comprising at least one groove.

4. The method according to claim 1, wherein said controlling is based on data about the characteristics of the at least one groove.

5. The method according to claim 1, further comprising retrieving data about the characteristics of the at least one groove for controlling said applying of the adhesive.

6. The method according to claim 5, wherein said data is obtained by scanning the rear side by a scanner.

7. The method according to claim 1, wherein the adhesive is applied at least on a peripheral portion of the rear side and/or on a peripheral portion of an upper side of the underlay element.

8. The method according to claim 7, wherein the peripheral portion of a board element comprises a peripheral portion of at least one floor or wall panel, into which the board element is configured to be divided and/or wherein the peripheral portion of an underlay element comprises a peripheral portion of at least one underlay unit, into which the underlay element is configured to be cut.

9. The method according to claim 1, wherein the adhesive is applied in a pattern arrangement.

10. The method according to claim 1, wherein at least two grooves have been discontinuously formed, and wherein said applying of the adhesive comprises: applying the adhesive between the discontinuous grooves, and/or applying the adhesive between corresponding cover portions of the underlay element.

11. The method according to claim 1, further comprising: cutting said underlay element into at least one underlay unit along at least one cutting portion, and/or dividing said board element into at least one floor or wall panel, along at least one dividing portion.

12. The method according to claim 1, further comprising controlling the applying of the adhesive such that no, or substantially no, adhesive is applied on a rear-side portion of the board element and/or an upper-side portion of the underlay element configured to be further processed.

13. The method according to claim 1, further comprising controlling said applying of the adhesive such that no, or substantially no, adhesive is applied in at least one cutting portion and/or at least one dividing portion.

14. The method according to claim 1, further comprising controlling said applying of the adhesive such that no, or substantially no, adhesive is applied: in a rear-side portion where a locking system, is configured to be formed, and/or in an upper-side portion of the at least one underlay unit configured to be provided along said rear-side portion.

15. The method according to claim 1, further comprising separating material elements, removed from the underlay element and the board element during or after processing of the board element and the underlay element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0157] The disclosure will in the following be described in connection to exemplary embodiments and in greater detail with reference to the appended exemplary drawings, wherein:

[0158] FIGS. 1a-1c illustrate in side views embodiments of a system for attaching an underlay element to a board element.

[0159] FIGS. 2a-2e illustrate embodiments of an adhesive applicator in perspective views and embodiments of a system for attaching an underlay element to a board element in side views.

[0160] FIGS. 3a-3d illustrate embodiments of adhesive applicator in perspective views and embodiments of a system for attaching an underlay element to a board element in side views.

[0161] FIG. 3e illustrates in a side view a zoomed-in section around a rear side of a board element comprising a surface roughness.

[0162] FIGS. 4a-4f illustrate embodiments of a board element and a panel in perspective views, a bottom view and side views as well as an underlay element in a top view.

[0163] FIGS. 5a-5l illustrate an embodiment of an attachment of an underlay unit to a panel in side views and embodiments of a system and a method for attaching an underlay element to a board element in bottom views and side views.

[0164] FIG. 6 is a flow chart illustrating an embodiment of a method for attaching an underlay element to a board element.

[0165] FIGS. 7a-7c illustrate in side views embodiments of a method for cutting an underlay element attached to a panel as well as an embodiment of a method for forming a locking system on the panel.

[0166] FIG. 7d illustrates in a side view an embodiment of an arrangement of an underlay element on a board element, wherein the underlay element comprises a pre-applied adhesive and is provided with a release liner.

[0167] FIGS. 8a-8f illustrate in bottom views embodiments of a panel on which an adhesive has been applied.

[0168] FIGS. 9a-9f illustrate embodiments of a panel on which an adhesive has been applied in bottom views and embodiments of an adhesive applicator in a top view and perspective views.

[0169] FIGS. 9g-9h illustrate in top views embodiments of an underlay element.

[0170] FIGS. 10a-10d illustrate in top views embodiments of an underlay element and in a bottom view an embodiment of a panel.

[0171] FIGS. 10e-10f illustrate embodiments of a board element and an underlay element in a bottom view and a top view, respectively, as well as in side views.

DETAILED DESCRIPTION

[0172] Next, embodiments of a method for attaching an underlay element 23, such as an underlay unit 23a, 23b, to a rear side 4 of a board element 1, such as a panel V, comprising at least one groove 10 and embodiments of a system 30 configured to implement the method will be described with reference to inter alia FIGS. 1a-1c, 2a-2e, 3a-3e, 5a-5l, 6 and 7a-7c. Reference will typically be made to a panel which is a floor panel, such as a plank or a tile, but it is understood that in some embodiments the panel may be a building panel, wall panel, ceiling panel or furniture panel.

[0173] FIGS. 1a-1c schematically illustrate in side views embodiments of a system 30 for attaching an underlay element 23 to a board element 1, such as a panel 1′. The system 30 comprises an adhesive applicator 40 and an underlay applier 31. The application of an adhesive 20 and/or the arrangement of an underlay element on the rear side may be carried out in a continuous process.

[0174] As shown in FIG. 1a, the system may further comprise a transportation device 50, 51 configured to transport the board element along a feeding path FP and/or the underlay element along a feeding path FP′. A feeding direction FD of the board element and a feeding direction FD′ of the underlay element may be parallel at least along a portion of the feeding paths, such as at a location where the underlay element is arranged on the rear side 4. The transportation device 50, 51 may be any transportation device known in the art. For example, it may comprise at least one roller 50a, 50b, 51a, 51b, 51c, rotating in the directions R1, R2, R3 and optionally comprising a driving mechanism (not shown) for driving at least one roller 50a-50b, 51a-51c, at least one conveyor belt 50c, or similarly. For sake of clarity, the transportation device 50 will sometimes be suppressed in embodiments disclosed herein. At least a component of the underlay applier 31 may be provided by the transportation device 51, such as being provided by the at least one roller 51c.

[0175] A speed of the board element and a speed of the underlay element along the feeding paths FP, FP′ may be synchronized during operation of the system 30, such as being substantially the same. For example, the speed may be 3-130 m/min, such as 15-100 m/min or 20-50 m/min.

[0176] The system 30 may further comprise a frame 32 in which the underlay applier and adhesive applicator, and optionally the transportation device, are arranged. Preferably, the underlay applier and the adhesive applicator, and optionally the transportation device, are fixedly mounted in the frame. The presence of a frame 32 is understood in the following, but will be suppressed for sake of clarity.

[0177] The underlay applier 31 may be loaded with an underlay element 23 configured to be arranged on the rear side of the board element. Generally, the underlay element may comprise at least one underlay unit 23a, 23b per se or it may be cuttable into at least one underlay unit 23a, 23b. The underlay element may be cut into suitable sizes by a cutting tool 52 which may be provided in the system 30, see, e.g., FIGS. 1a-1c and 2d. The cutting tool may comprise a rotating cutting device, a carving device or a knife arrangement comprising 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 displaceably mounted in the frame. The cutting tool 52 may be positioned downstream of the underlay applier 31 along the feeding path FP′. Alternatively, as noted above, the underlay applier may comprise at least one underlay unit 23a, 23b that may be stored therein and that may be delivered therefrom, see, e.g., FIG. 3d.

[0178] The adhesive applicator 40 may comprise or may be connected to an adhesive reservoir 42. Moreover, a control unit 44 may control the application of the adhesive.

[0179] The embodiment in FIG. 1a schematically illustrates a general adhesive applicator 40, which may be a contact applicator, such as a roll coater 43 or a slot-die coater 41, or a non-contact applicator, such as a spray coater 45 or a curtain coater 46. As shown in FIG. 1a, the adhesive applicator may be configured to apply adhesive 20 on the board element 1, such as a panel V. Moreover, as shown in FIG. 1b, the adhesive applicator may be configured to apply adhesive on the underlay element 23, such as an underlay unit 23a, 23b. Also, as shown in FIG. 1c, the adhesive applicator may be configured to apply adhesive on the board element 1, such as a panel V, and on the underlay element 23, such as an underlay unit 23a, 23b.

[0180] A position of the underlay element may have to be synchronized with a position of the board element, such that the underlay element becomes aligned with the board element. The synchronization may be controlled by the control unit 44.

[0181] The adhesive may be a hot-melt adhesive, such as a PUR hot-melt adhesive, but other adhesives suitable for the intended purpose as will be clear from the discussion herein are equally conceivable.

[0182] In a first example, the panel may be an SPC panel, the PUR hot-melt adhesive may be KLEIBERIT 711.2.00, and the underlay element may be an IXPE foam, an EVA foam or a cork sheet. In a second example, the panel may be an EPC panel, the PUR hot-melt adhesive may be H.B. Fuller Rapidex NP 2075 LT, and the underlay element may be an IXPE foam, an EVA foam or a cork sheet. In a third example, the panel may be an LVT tile, the PUR hot-melt adhesive may be H.B. Fuller Rapidex NP 2075 LT, and the underlay element may be an IXPE foam, an EVA foam or a cork sheet.

[0183] As shown in FIG. 1a, the system 30 disclosed herein may further comprise a heating device 33 for heating the adhesive, such as a hot-melt adhesive, before application. For example, the heating device may heat the adhesive to an application temperature. The system 30 in any embodiment disclosed herein may further comprise a post-treatment device 34, such as a drying device and/or a radiation device, such as an infrared or an ultraviolet radiation device. The post-treatment device may be located at and/or downstream of the underlay applier 31 along the feeding path FP′. Alternatively, or additionally, however, in some embodiments the post-treatment device 34, such as an ultraviolet radiation device, may be located upstream of the underlay applier 31. Alternatively, or additionally, the system may comprise a post-heating device 36 configured to heat the adhesive after its application.

[0184] Such embodiments are shown in, e.g., FIG. 1c.

[0185] In some embodiments, and as show in FIG. 1b, the post-treatment may comprise exposing the adhesive to moisture, such as by a moisture regulator 39. In fact, the method may further comprise controlling an applied moisture content and/or an RH value. Preferably, the moisture regulator is provided upstream of the underlay applier 31 along the feeding path FP and/or FP′.

[0186] Optionally, the system 30 may further comprise a pressure device 35 configured to exert pressure on the underlay element and/or the board element, preferably located at and/or downstream of the underlay applier 31 along the feeding path FP′. At least a component of the pressure device 35 may be provided by the transportation device 50, 51, such as being provided by the at least one roller 50b, 51c, or by the at least one roller 51c and a part of the transportation device 50, such as the at least one conveyor belt 50c, or similarly. For example, a distance between components of the transportation device between which the board element may be fed, such as a pair of rollers or a roller and a portion of a conveyor belt, may be smaller than a combined thickness of the board element and the underlay element, preferably including the adhesive.

[0187] As shown schematically in the embodiments in FIGS. 1b-1c, 2a-2b and 2e, the adhesive may be applied by contact application, such as by slot-die coating or by roller coating. As described above, the adhesive applicator 40 in FIG. 1a may be a contact applicator, such as a roll coater 43 or a slot-die coater 41. Moreover, any or both of the adhesive applicators 40 in FIG. 1c may be a contact applicator, such as a roll coater 43 or a slot-die coater 41.

[0188] FIG. 1b shows a slot-die coater 41 that applies adhesive 20 on the underlay element 23, such as directly on it. The adhesive may be applied from below, such as when the underlay element is fed in a horizontal or an inclined direction. FIG. 2a generally shows in a perspective view slot-die coating on a substrate 60, which may be a board element 1, such as a panel V, or an underlay element 23, such as an underlay 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 feeding direction FD or FD′, respectively, the direction TD, TD′ preferably being parallel with the rear side 4 in operation. In some embodiments, however, the adhesive coating on the substrate 60 may be discontinuous in the direction TD or TD′, see FIG. 2e where the slot-die coater is used in conjunction 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 board element or an underlay element, respectively.

[0189] The side view in FIG. 2b shows an embodiment in which the adhesive applicator 40 comprises at least one roll coater 43, such as an application roller 43a and a metering roller 43b, and preferably a doctor blade 43c. The adhesive applicator may apply adhesive 20 on the board element 1, such as directly on it. Generally herein, it is understood that the at least one roll coater 43 may rotate during application of the adhesive. Preferably, a rotating mechanism (not shown) may be configured to rotate the at least one roll coater 43.

[0190] As schematically shown in side views and in a perspective view in the embodiments in FIGS. 2c-2d and 3a-3b, the adhesive may be applied by non-contact application, such as by spraying or curtain coating. It is recalled that the adhesive applicator 40 in FIG. 1a may be a non-contact applicator, such as a spray coater 45 or a curtain coater 46. In operation, the non-contact applicator may generally be spaced from the underlay element.

[0191] FIG. 2c generally illustrates non-contact application of an adhesive 20 on a board element 1 by an adhesive applicator 40, such as a spray coater 45 or a curtain coater 46.

[0192] Moreover, FIG. 2d generally illustrates non-contact application of an adhesive 20 on an underlay element 23 by an adhesive applicator 40, such as a spray coater 45 or a curtain coater 46. The application of the adhesive and/or the arrangement of the underlay element on the rear side may be carried out in a continuous process. The transportation device 50, 51 configured to transport the board element along a feeding path FP and/or the underlay element along a feeding path FP′ may be implemented as described elsewhere in this disclosure, such as by at least one roller 50a, 50b, 51a, 51b, rotating in the directions R1, R2, R3, and optionally comprising a driving mechanism (not shown) for driving at least one roller, at least one conveyor belt, or similarly. Other features of the embodiment in FIG. 2c may be similar to the embodiment described in relation to any of the embodiments in FIGS. 1a-1c, whereby reference is made thereto.

[0193] FIG. 3a is a zoomed-in perspective view of the area around the adhesive applicator 40 in FIG. 2d, which here is provided in the form of a spray coater 45. It is clear that a spray coater 45 may apply adhesive 20 on the rear side 4, such as on a remaining portion 4b described below, as schematically illustrated in FIG. 3b, which may be a zoomed-in perspective view of the area around the adhesive applicator 40 in FIG. 2c.

[0194] In some embodiments, and as discussed elsewhere in the disclosure, the non-contact applicator 40 may be a curtain coater 46 which is schematically illustrated in FIG. 3c in operation on a substrate 60, which here is a board element 1, such as panel 1′. It is understood, however, that in some embodiments the substrate 60 on which the adhesive 20 is applied may be an underlay element. The adhesive 20 may be stored in an adhesive reservoir 42 as shown in FIG. 3c.

[0195] In some embodiments, the adhesive applicator 40 in FIG. 2d may be a contact applicator, such as a roll coater 43 or a slot-die coater 41.

[0196] It is understood that in the embodiments in FIGS. 2b-2c and 3c, after the application of the adhesive, an underlay element may be arranged on the board element 1 by the underlay applier 31, which may be embodied in accordance with any embodiment described herein, such as in any of FIGS. 1a-1c, 2d, 3d or 5f.

[0197] The arrangement of the underlay element on the rear side may be carried out in a discontinuous process, for example such that the underlay applier 31 operates intermittently. As illustrated schematically in FIG. 3d, the underlay applier 31 in any embodiment herein, such as in any of FIGS. 1a-1c, 2b-2c, 3c and 5f, may comprise at least one underlay unit 23a, 23b that may be stored therein. The area and/or shape of an underlay unit 23a, 23b may correspond to the area and/or a shape of the rear side of the board element 1 or panel 1′. The underlay applier may be adapted to arrange the at least one underlay unit on the rear side 4 of the board element 1 or panel 1′. The at least one underlay unit may be arranged thereon sequentially, such as individually. Any known method in the art may be utilized, for example a method using suction cups 55. The control unit 44 may control the operation of the underlay unit.

[0198] Optionally, the system 30 in FIG. 2d or 3d may further comprise a pressure device 35 configured to exert pressure on the underlay element and/or the board element, preferably located at and/or downstream of the underlay applier 31 along the feeding path FP′.

[0199] FIGS. 4a-4f illustrate embodiments of a board element 1, such as a panel V, obtainable by at least some of the embodiments of the method disclosed herein. Indeed, embodiments of the system 30 described herein, such as in any of FIGS. 1a-c, 2a-2e, 3a-3d and 5a-5l, may be used to implement a method for attaching an underlay element 23, such as an underlay unit 23a, 23b to a board element 1 or a panel 1′, which are shown in a perspective view in FIG. 4a and FIG. 4b, respectively.

[0200] A panel 1′ and an underlay unit 23b may be referred to as a panel assembly. FIG. 4c illustrates in a bottom view an embodiment of a rear side 4 of a panel V comprising a groove portion 4a comprising at least one groove 10 and a remaining portion 4b without any grooves. The remaining portion may be provided in a horizontal plane HP extending along the rear side. The horizontal plane HP may be parallel with a horizontal plane extending along a front side 2 of the panel 1′.

[0201] As shown in FIG. 4c, the at least one groove 10 is preferably provided in an interior of the rear side 4, thereby being spaced from a pair of opposite edge portions, such as opposite short edge portions 1c, 1d, of the panel, preferably being spaced from all edge portions 1a, 1b, 1c, 1d.

[0202] As shown in the embodiment in FIG. 4d in a top view, the underlay element 23, such as the underlay unit 23a, 23b, comprises an upper side 21 configured to face the board element or panel and an opposite underside 22, cf. FIG. 4e. The upper side 21 comprises a cover portion 21a and a corresponding residual portion 21b configured to face and to be aligned with the groove portion 4a and remaining portion 4b, respectively, when the underlay element is attached to the rear side.

[0203] FIGS. 4e and 4f schematically illustrate in side views an embodiment of a panel 1′ comprising long edge portions 1a, 1b and short edge portions 1c, 1d, respectively, wherein an underlay unit 23b is attached to the rear side 4 of the panel. For example, the panel and underlay unit may correspond to those disclosed in FIGS. 4c-4d. The adhesive 20 contacts at least a portion of a remaining portion 4b and a corresponding residual portion 21b of the underlay element and thereby attaches the underlay unit to the rear side.

[0204] The panel 1′, or generally the board element 1, may comprise a layer arrangement 3 comprising at least one layer 3a, 3b, 3c. Optionally, the layer arrangement 3 may comprise a bottom layer 3c which may be a backing layer. Thereby, the at least one groove 10 at least partly penetrates the at least one layer 3a, 3b, 3c, such as at least the bottom layer 3c.

[0205] Generally, the panel 1′ may comprise a locking system 9 for horizontal and/or vertical locking, preferably a mechanical locking system, on at least one edge portion, preferably on two opposite edge portions thereof. FIGS. 4c-4e illustrate a mechanical vertical locking system comprising a tongue 9a, 9a′ and a tongue groove 9b, 9b′ formed on the long edge portions 1a, 1b and on the short edge portions 1c, 1d. Moreover, FIGS. 4c-4e illustrate a mechanical horizontal locking system comprising a locking element 8, 8′ provided on a locking strip 6, 6′ and a locking groove 14, 14′ formed on the long 1a, 1b and short 1c, 1d edge portions. The tongue 9a on the long edge portion 1a may be integrally formed with the panel and the tongue 9a′ on the short edge portion 1d may be separately formed from the panel and being provided in an insertion groove 15. The tongue 9a′ may be a displaceable tongue, preferably being flexible. It is clear that the locking system in FIGS. 4c-4f is exemplary and that other locking systems are equally conceivable.

[0206] In some embodiments, the locking system 9 may comprise at least one connecting element configured to be attached to the rear side 4 of adjacent panels, such as in their corner portions, for interconnecting them. Each connecting element may comprise an adhesive layer configured to contact the rear side of adjacent panels. For example, the connecting element may be an adhesive tape.

[0207] The panel may extend in a first horizontal direction X and a second horizontal direction Y, which may extend in parallel with long edge portions 1a, 1b and the short edge portions 1c, 1d of the panel, respectively.

[0208] A groove length GL of the at least one groove 10, such as along the first horizontal direction X, may be less than a distance between components of the locking system 9, such as on the distance between the short edge portions 1c, 1d. In an embodiment, the groove length GL may be at least 75% of the distance between components of the locking system 9, such as at least 85% of the distance, such as at least 90% of the distance. In a first example, the groove length GL is less than a distance from an inner wall of the locking groove 14′ to a vertical plane VP extending along an edge portion of the panel, such as a short edge portion 1d comprising the locking strip 6′. The vertical plane VP may be provided along an upper portion of the short edge portion 1d and may extend perpendicularly to the horizontal plane HP. In a second example, the groove length GL is less than a distance from the inner wall of the locking groove 14′ to an innermost wall portion of the insertion groove 15, which may be provided on the short edge portion 1d comprising the locking strip 6′.

[0209] It is conceivable, however, and as illustrated in FIG. 4b, that the panel 1′ in some embodiments is not provided with a mechanical locking system. For example, it may be adapted to be provided loosely on a subfloor or it may be glued to the subfloor.

[0210] The remaining portion 4b may have a larger thickness Tb than a thickness Ta of the groove portion 4a. Moreover, a main portion of the remaining portion preferably has a constant thickness, such as in areas that are spaced from the edge portions 1a-1d where the locking system 9, preferably a mechanical locking system comprising a tongue 9a, 9a′ and a tongue groove 9b, 9b′ and/or a locking element 8, 8′ and a locking groove 14, 14′, is formed.

[0211] Preferably, a shape of end portions 16 of the grooves 10 along their longitudinal direction are curved. For example, this shape may be obtained when the grooves are formed by a rotating cutting device.

[0212] The at least one layer 3a, 3b, 3c in the layer arrangement 3 may each comprise a polymer-based material, such as a thermoplastic material, and, preferably, a filler. The layer(s) may be (co-)extruded. In this embodiment the thermoplastic material is PVC, but it is clear that other thermoplastic materials may be used, such as PE, PP, PET or ABS. The filler of any layer may be a mineral material, such as calcium carbonate (CaCO.sub.3) or stone material, such as stone powder, or similarly. Optionally, at least some of the layers, such as all layers, may comprise a plasticizer and/or additives. By way of example, the floor panel may be an LVT tile, an SPC panel, an EPC panel, or an WPC panel.

[0213] In other embodiments, the polymer-based material may be a thermoset. For example, the panel may comprise an HDF core and, optionally, at least one wood-fibre based layer attached to the core. By way of example, the floor panel or wall panel may be a Nadura® panel or a Woodura® panel.

[0214] In other embodiments, the panel may be a mineral-based panel, such as a cementitious panel or such as comprising magnesium oxide and, optionally, magnesium chloride and/or magnesium sulphate. By way of example, the panel, such as a floor panel or wall panel, may be, or may comprise, an MgO panel, cement board or fibre cement board.

[0215] The underlay element 23, such as the underlay unit 23a, 23b, may comprise a resilient material. Preferably, the underlay element in any of the embodiments disclosed herein, such as in FIGS. 1a-1c, 2d, 3d-3e, 4a-4b, 4d-4f, 5a-5d, 5f-5l and 7a-7c is a foam, such as a closed-cell foam, for example an IXPE foam, an EVA foam, an XLPE foam, a foam rubber or a PU foam. In some embodiments, however, such as in any of said figures, the underlay element may comprise cork, such as being a cork sheet. In yet some embodiments, the underlay element may comprise a thermosetting resin, such as PU.

[0216] It is understood that similar features as described in FIGS. 4b-4f for a panel 1′ and an underlay unit 23b also are possible for a board element 1 and an underlay unit 23a.

[0217] Embodiments of a system 30 and a method for attaching an underlay element, such as an underlay unit, to a board element, such as a panel, are shown schematically in the embodiments in FIGS. 5a-5l and illustrated in a flow chart in FIG. 6 (Box S10), respectively. In the following reference will also be made to the system described in relation to e.g. FIGS. 1a-1c, 2a-2e and 3a-3d and the embodiments of a board element/panel in FIGS. 4a-4f and 7a-7c.

[0218] FIGS. 5a-5d schematically illustrate in side views an arrangement of an underlay unit 23b on a rear side of a panel 1′. Moreover, FIGS. 5e-5f illustrate an arrangement of an underlay unit 23a on a rear side of a board element 1, preferably in a continuous process, whereby the board element and the underlay element are fed along a feeding path FP, FP′, such as along a feeding direction FD, FD′.

[0219] Generally, the method comprises providing a board element 1 as illustrated in FIG. 5e or a panel V as illustrated in FIG. 4c or FIG. 5a and an underlay element 23 or an underlay unit 23a, 23b as illustrated in FIG. 4d or FIG. 5a (Box S11), wherein the board element or panel comprises a groove portion 4a. Moreover, the method comprises applying an adhesive 20 on at least a portion of the remaining portion 4b and/or on at least a portion of the corresponding residual portion 21b of the underlay element (Box S12), see FIGS. 5b and 5f. The application may also be implemented as in any of the embodiment described in e.g. FIGS. 1a-1c, 2a-2e and 3a-3c.

[0220] The adhesive applicator 40 in FIG. 5f may comprise at least one roll coater 43. The adhesive 20 may be applied during a displacement of the board element 1 and/or the underlay element 23 along the feeding path FP, FP′. Preferably, at least two roll coaters 43 are spaced from each other in a transverse direction TD. Thereby, no, or substantially no, adhesive is applied in at least one cutting portion 12a where the underlay element is configured to be cut into at least one underlay unit, such as at least two underlay units, and/or in at least one dividing portion 12b where the board 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 a rear-side portion 4d where a locking system 9 of at least one panel 1′ is configured to be formed. The divided panels may be essentially similar.

[0221] After application of the adhesive as described above, the underlay element 23 is arranged on the rear side of the board element or panel (Box S13) by an underlay applier 31 such that the adhesive contacts the underlay element and the rear side, see, e.g., FIGS. 5c and 5f. Preferably, the arranging of the underlay element on the rear side is performed during a displacement of the board element and/or the underlay element along the feeding path FP and/or FP′, such as in any of FIGS. 1a-1c and 2d, but it is equally conceivable that said arranging may be carried out in a discontinuous process as described, e.g., in relation to FIG. 3d.

[0222] In a first scenario, the board element is a panel 1′ and the underlay element is an underlay unit 23b, wherein no dividing and/or cutting is needed (Box S14), such as in the embodiments in FIGS. 4b-4d, 5c, 5j, 5I and 7a. Hence, the panel and underlay unit may have formats that are adapted to each other. For example, the panel may be adapted to be provided loosely on a subfloor or it may be glued to the subfloor. In other examples, a locking system 9, preferably a mechanical locking system comprising a tongue 9a, 9a′ and a tongue groove 9b, 9b′ and/or a locking element 8, 8′ and a locking groove 14, 14′, may be pre-formed on at least one edge portion of the panel 1a, 1b, 1c, 1d, such as on all edge portions, see e.g. FIGS. 4c-4f, 5d and 7c. Optionally, however, a locking system 9, preferably a mechanical locking system comprising a tongue 9a, 9a′ and a tongue groove 9b, 9b′ and/or a locking element 8, 8′ and a locking groove 14, 14′, may be post-formed (Box S15) 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, see e.g. FIGS. 4c-4f, 5d and 7b-c. FIG. 5d shows a panel V comprising a mechanical locking system, such as fold-down mechanical locking system, for horizontal and/or vertical locking. In any of the embodiments of the panel described herein, with or without a locking system, horizontally outermost portions of the underlay element and the rear side may be aligned, such as along their first X and/or second Y horizontal directions.

[0223] In a second scenario, and as illustrated in the embodiments in, e.g., FIGS. 1a-1c, 2d, 3d, 5g-5l and 7a-7c, the board element and/or the underlay element may be divided and/or cut (Box S14). The embodiments in FIGS. 5g-5i and FIG. 5k illustrate cross-sectional side views of the board element 1 shown in FIG. 5f along the section A-A.

[0224] In a first example, the attached underlay element may be processed separately from the board element or panel (Box S20), such as illustrated in the embodiments in FIGS. 5g-5j or 7a-7c. As shown in FIGS. 5g-5h and 7a-7b, the underlay element 23 or underlay unit 23a may be cut into at least one underlay unit 23b along at least one cutting portion 12a, preferably by a cutting tool 52 (Box S21). By way of example, the cutting tool 52 may be a rotating cutting device, a carving device or a knife arrangement. Thereby, material elements 23c may be removed from the underlay element. For example, a format of the cut underlay unit, such as a length along its first X and/or a second Y horizontal direction, may be adapted to a format of the panel, such as along its first and/or second horizontal direction. An inner portion of the underlay element may be cut as shown in FIGS. 5g-5h and/or an outer portion of the underlay element may be cut as shown in FIGS. 7a-7b. Optionally, at least one chamfer 28 may be formed, preferably after the underlay element has been arranged on the rear side.

[0225] Optionally, and as shown in FIG. 5i, the board element may be divided into at least one panel, such as at least two panels, V along at least one dividing portion 12b (Box S22), preferably by a dividing tool 54, for example comprising rotating cutting elements, such as a circular saw blade.

[0226] In a second example, and as illustrated in the embodiment in FIGS. 5k-5l, the dividing of the board element and the cutting of the attached underlay element may be performed jointly (Box S24), preferably by the same processing tool 56, which may comprise a cutting tool 52 and/or a dividing tool 54.

[0227] In some embodiments, no further processing of the panel or underlay element may be needed in e.g. FIGS. 5j, 5l or 7a, which thereby may be in their final formats. For example, the panel may be adapted to be provided loosely on or glued to a subfloor. Optionally, however, and as shown in FIG. 7c, and also in FIG. 5d, a locking system 9, preferably a mechanical locking system, may be formed on at least one edge portion of the panel 1a, 1b, 1c, 1d, such as on all edge portions (Box S23) according to known principles in the art.

[0228] Optionally, the removed material elements 23c, 4c, such as chips, shavings or strips, from the underlay element and the board element during or after the cutting and dividing, may be separated from each other (Box S25). In some embodiments, also the material elements of the adhesive contacting the board element and/or underlay element may be separated. In a first example, the method comprises cutting the underlay element only and the thereafter dividing the board element. Thereby, the removed material elements may be easily separated, e.g. by separate vacuum devices. In a second example, the method comprises performing cutting and dividing in the same operation, the method optionally also comprising forming a locking system 9. The separation of the material elements may then be based on at least one attribute of the underlay element and the board element, and optionally the adhesive. The separation may be implemented by a separation device 37 in the system 30, which is illustrated schematically in FIG. 5k. The separation device 37 may be configured to screen or sieve the material elements or it may use gravity separation, such as specific gravity separation, of the material elements. For example, density separation or cyclonic separation may be utilized. In any of the first and second examples above, optionally, no, or substantially no, adhesive is applied in the cutting portion 12a and/or the dividing portion 12b.

[0229] In some embodiments, the removed material elements 23c, 4c from the underlay element and the board element during or after a forming of a locking system 9 on the board element, may be separated from each other. At least a portion of the locking system may be formed by removing material from a rear-side portion 4d, cf. FIG. 7a.

[0230] FIGS. 8a-8f and 9a-9b illustrate in bottom views embodiments of a panel V comprising an applied adhesive 20.

[0231] Generally, the adhesive in any of e.g. FIGS. 1a-1c, 2a-2e, 3a-3e, 5b, 5f, 8a-8f and 9a-9b may be applied continuously or intermittently on at least one portion of the board element 1 and/or underlay element 23 along the feeding path FP, FP′, such as along the feeding direction FD, FD′. Thus, the applied adhesive may extend continuously or discontinuously along the first X and/or the second Y horizontal direction.

[0232] Any of the continuous or intermittent application of the adhesive disclosed herein may be a broad application as shown in, e.g., in the embodiments in FIGS. 5f, 8a, 8e-8f and 9a-b and/or a line application as shown in, e.g., in the embodiments in FIGS. 8b-8e and 9b. In FIGS. 8a, 8e-8f and 9a-9b, at least a portion of the adhesive 20 is applied over substantially the entire width of the remaining portion 4b along the second horizontal direction Y between long edge portions 1a, 1b. FIGS. 8a and 9a show embodiments wherein the adhesive is applied over substantially the entire remaining portion 4b. In FIG. 5f, the adhesive is applied as at least two, such as three, broad applications, which may be spaced from each other as described above. In FIGS. 8b-8f and 9b, the adhesive is applied over at least one portion of a width of the remaining portion 4b along the first X and/or the second Y horizontal direction, hence preferably between short edge portions 1c, 1d and/or between long edge portions 1a, 1b.

[0233] In FIGS. 8a-8f and 9a-9b, the adhesive 20 is applied in a peripheral portion 5 of the rear side 4. As illustrated in FIG. 8b by the broken lines, the peripheral portion 5, 5′ of the rear side 4 or the upper side 21 may be located within a distance of 10%, preferably 5%, of a total length LX, LY of the board element or underlay element from a horizontally outermost portion of the rear side or the upper side. The adhesive may be applied along the long edge portions 1a, 1b and/or along the short edge portions 1c, 1d.

[0234] FIGS. 8a-8c, 8e-8f and 9b illustrate application, which may be line application or broad application, whereby the adhesive is applied along, i.e. in parallel with, the first X and/or the second Y horizontal direction. FIGS. 8d and 9a illustrate application, which may be line application and broad application, respectively, whereby the adhesive is applied at an angle with respect the first X and/or the second Y horizontal direction.

[0235] In any of the embodiments disclosed herein, such as illustrated in FIGS. 8c and 9a-9b, the adhesive 20 may be applied in a pattern arrangement 26 on the remaining portion 4b and/or on the corresponding residual portion 21b. The embodiment in FIG. 9a illustrates adhesive provided on the remaining portion 4b, wherein a basic application design 27 of the adhesive in the pattern arrangement 26 is provided in the form of a grid.

[0236] The pattern arrangement may be a primary pattern 24, such as in FIG. 8c or FIG. 9a. As illustrated in FIG. 9b, the pattern arrangement 26 may further comprise at least one further pattern, such as a secondary pattern 25. The secondary pattern may comprise at least two primary patterns 24 which may be spaced from each other, such as along the first X and/or second Y horizontal direction. In FIG. 9b the primary patterns 24 are spaced from each other along the first horizontal direction X. Optionally, additional adhesive 20 may be applied between the primary patterns, which for example may be applied by line application, such as in a peripheral portion 5, 5′ as discussed above. A basic application design 27 of the adhesive in FIG. 9b is shaped as a circle. As shown in the embodiments in FIG. 9d, however, other basic application designs are equally conceivable, such as an oval, or a polygon, such as a triangle, a square or a star, etc.

[0237] Generally, and as shown in FIGS. 8f and 9b, the groove portion 4a may comprise at least two groove arrangements 11, each groove arrangement comprising at least one groove 10, preferably a plurality of grooves. The grooves may be discontinuously formed in the rear side 4 and their longitudinal extension may be parallel with the long edge portions 1a, 1b. An extension, such as a longitudinal extension, of the grooves in each groove arrangement, preferably are parallel to each other. The groove arrangements may be spaced from each other in the first X and/or second Y horizontal direction of the board element or panel. The groove arrangements may be spaced by a separation portion 13 provided in the rear side 4, preferably extending continuously along the second horizontal direction Y, such as between the long edge portions 1a, 1b. For example, the separation portion may comprise a rectangularly shaped portion.

[0238] As shown in FIG. 8f, the adhesive 20 may be applied, preferably controlled to be applied, between the groove arrangements 11, such as along the first horizontal direction X. The adhesive may be applied in the separation portion 13, for example covering the entire separation portion. Optionally, and as illustrated in FIG. 8f, the adhesive may also be applied between the grooves 10 of a groove arrangement 11, such as along the second horizontal direction Y. For example, the adhesive may be applied between end portions 16 of the grooves 10.

[0239] The adhesive 20, for example being provided in a primary pattern 24 as in FIG. 9b, may be applied between the groove arrangements 11, such as along the first horizontal direction X.

[0240] Generally, the pattern arrangement 26 may be applied by a contact application, such as by a slot-die coater 41 or by a roll coater 43, or by non-contact application, such as by a spray coater 45 or a curtain coater 46. The embodiments in, e.g., FIGS. 1a-1c, 2a-2e, 3a-3d and 5a-5l described elsewhere in the disclosure may be used for implementing the contact application or non-contact application.

[0241] Additionally, the embodiments in FIGS. 9c and 9e illustrate in a top view and a perspective view an engraved roll coater 43 comprising a plurality of structural elements 47, such as indentations and/or protrusions. The structural elements of the roll coater in FIGS. 9c and 9e may correspond to the pattern arrangement 26 in FIG. 9a and the primary pattern 24 in FIG. 9b, respectively. The structural elements 47 in FIG. 9c are provided along the circumference of the roll coater while the structural elements 47 in FIG. 9e are arranged in groups 48, each group preferably being spaced from each other along the circumference of the roll coater. It is clear that the adhesive applicator 40 in FIG. 9c or 9e may be connected to an adhesive reservoir 42 as described elsewhere herein. Generally, the adhesive applicator may comprise at least one roll coater, whereby the roll coater in FIG. 9c or 9e may be an application roller 43a, cf. the embodiment in FIG. 2b.

[0242] The roll coater in FIGS. 9c and 9e may implement continuous or intermittent application of adhesive. Continuous application may be implemented as, e.g., in FIG. 2b. For example, the roll coater 43 and the transportation device 50 may be fixedly mounted, such as in the frame 32. Moreover, as illustrated in FIG. 2b by the dashed arrow, intermittent application may generally be implemented by bringing the roll coater 43 in and out of contact with the board element 1 and/or the underlay element 23 while displacing the same along a feeding path FP, FP′. In a first example, the roll coater 43 is displaceably mounted, such as in the frame 32. In a second example, the transportation device 50 is displaceably mounted, such as in the frame 32.

[0243] Generally, the adhesive may be applied by transfer application. The embodiment in FIG. 9f illustrates in a perspective view a part of an adhesive applicator 40 comprising an adhesive unit 49 in the form of a slot-die coater 41 and a transfer roller 49′ capable of applying adhesive 20 intermittently and/or in a pattern arrangement 26 on a substrate 60, which may be transported along a feeding path FP, FP′ in a feeding direction FD, FD′. As described above, the substrate 60 may be a board element 1, such as a panel 1′, or an underlay element 23, such as an underlay unit 23a, 23b. The slot-die coater 41 may apply adhesive 20 on the roll coater 43 along the circumference and a longitudinal extension L thereof, such as intermittently and/or by applying the adhesive in a pattern arrangement and, preferably, during rotation of thereof. For example, the intermittent application of adhesive shown in, e.g., FIG. 8f and FIG. 10b described herein may be obtained by the adhesive applicator 40 in FIG. 9f. Moreover, the application of the adhesive shown in, e.g., FIGS. 8b, 8e and 10e-101 described herein may be obtained by the adhesive applicator 40 in FIG. 9f. In some embodiments, the adhesive coating on the substrate 60 in FIG. 9f may be discontinuous in the direction TD or TD′. For example, the slot-die coater may be used in conjunction with at least one mask 40a, which is indicated by broken lines in FIG. 9f.

[0244] It is understood that the application of adhesive on the board element, e.g., as that described in relation to any of FIGS. 8a-8f and 9a-9f, describing broad application, line application, peripheral application, pattern arrangements, etc., is equally conceivable as an adhesive application on the corresponding residual portion 21b of an underlay element. Examples of such applications are illustrated in FIGS. 10a-10b, which illustrate embodiments of an underlay element 23b in top views. These applications are similar to the applications shown in FIG. 8a and FIG. 8f, respectively. Preferably, the adhesive 20 is not applied in the cover portion 21a. However, in some embodiments herein, a main portion, e.g., more than 50%, of the cover portion may be free from adhesive.

[0245] As shown in a bottom view in the embodiment in FIG. 10c, it is noted that in some embodiments a longitudinal extension of the grooves 10, may be parallel with the short edge portions 1c, 1d. The embodiment in FIG. 10d illustrates in a top view an underlay unit 23b configured to be attached to the panel 1′ in FIG. 10c, wherein the cover portion 21a and the corresponding residual portion 21b are indicated. FIGS. 10c and 10d are shown with adhesive 20 applied over substantially the entire remaining portion 4b and/or corresponding residual portion 21b, respectively. Preferably, the adhesive is not applied in the groove portion 4a or the cover portion 21a.

[0246] In some embodiments, as shown in FIGS. 9g and 9h, the underlay element 23, such as an underlay unit 23a, 23b, may be discontinuously formed, comprising perforations 21d and/or at least one hole 21e therein. The at least one hole 21e may be configured to align with groove portion 4a of the panel. Thereby, even less adhesive may be needed for the attachment. Other features may be similar to those described elsewhere herein, e.g., as in FIGS. 3e, 4a-4f, 5a-5l, 7a-7d, 8a-8f, 9a-9b and 10a-10f.

[0247] The method may comprise controlling the applying of the adhesive 20 such that no, or substantially no, adhesive is applied in the at least one cutting portion 12a and/or the at least one dividing portion 12b. Also, the method may comprise controlling the applying of the adhesive such that no, or substantially no, adhesive is applied in a rear-side portion 4d where a locking system 9 of at least one panel V is configured to be formed and/or in an upper-side portion 21c of the at least one underlay unit configured to contact the rear-side portion 4d. An example of such a rear-side portion 4d is shown in the embodiment in FIG. 7a.

[0248] FIG. 10e illustrates an embodiment of a board element 1 comprising applied adhesive 20 in a bottom view and an underlay unit 23a in a side view. Moreover, FIG. 10f illustrates an embodiment of an underlay unit 23b comprising applied adhesive 20 in a top view and a board element 1 in a side view. In each of these embodiments, no, or substantially no, adhesive is applied in the at least one cutting portion 12a and/or the at least one dividing portion 12b. By way of example, the adhesive in FIG. 10e or 101 may be applied by a slot-die coater 41 or a spray coater 45 or even by an engraved roll coater 43. In each of FIGS. 10e-10f, the underlay unit 23a or underlay units 23b may be attached to the respective board element 1 or panels 1′.

[0249] As shown in FIG. 10e, the adhesive may be applied in peripheral portions 7 of at least two panels 1′ into which the board element 1 is configured to be divided. Moreover, FIG. 10f illustrates that the adhesive may be applied in peripheral portions 7′ of at least two underlay units 23b into which the underlay element 23a is configured to be cut. As indicated in FIGS. 10e and 10f for the rightmost panel V and underlay unit 23b, a peripheral portion 7, 7′ may be delimited similarly as the peripheral portion 5, 5′ described above. For example, in any of these embodiments, the adhesive may be applied in line application, such as extending along the first horizontal direction X, for example along long edge portions, of the panels V or underlay units 23b. Optionally, as shown in FIG. 10e, adhesive 20 may also be applied in line application, such as extending along the second horizontal direction Y, for example along short edge portions, of the panels 1′ or underlay units 23b, preferably, no, or substantially no, adhesive being applied in the at least one cutting 12a and/or dividing 12b portion. The adhesive is preferably applied in a peripheral portion 5, 5′.

[0250] Generally, the adhesive may be controlled to be applied on the remaining portion 4b and/or the residual portion 21b only. The method may comprise the act of controlling the applying of the adhesive 20 based on a characteristic of the at least one groove 10. For example, the control unit 44 may control the application. The adhesive may be applied by spraying, curtain coating, slot-die coating or roller coating. The characteristic may be at least one selected from the group of a shape, an extension, a position of the at least one groove 10 or the at least one groove arrangement 11 in the first X and/or the second Y horizontal direction, and a distance between at least one pair of grooves or a pair of groove arrangements in the first and/or the second horizontal direction. The controlling may comprise controlling a positioning of the adhesive on the board element and/or the underlay element and, optionally, an amount of the adhesive.

[0251] In any embodiment described herein, and as schematically illustrated in FIGS. 1a-1b, data about the characteristics may be retrieved by the control unit 44 from a data storage unit 57, which may store predetermined data and/or collected data. For simplicity, the data storage unit 57 will often be suppressed in the figures. For example, the data may be obtained or collected by scanning the rear side 4 by a scanner 58, preferably being connected to the data storage unit 57. The scanner 58 may comprise a horizontal 58a and/or a vertical 58b scanning unit configured to determine data about the groove(s) along at least one direction X, Y, Z, such as along at least one horizontal direction X, Y and/or along a vertical direction Z. The scanning device 58 may comprise an image sensor, such as a digital camera, and/or a laser triangulation device. For example, the scanner 58, optionally comprising a horizontal 58a and/or a vertical 58b scanning unit, may be provided in a vision inspection system.

[0252] In some embodiments, data about the characteristics, which may be predetermined data and/or collected data, may determine a position of the adhesive applier 40, such as the roll coater 43 or the slot-die coater 41, with respect to the board element 1 and/or the underlay element 23.

[0253] The adhesive 20 may be controlled to be applied between at least one groove arrangement 11 and/or discontinuous grooves 10, such as in FIG. 9b.

[0254] Generally, the adhesive 20 may be post-treated by a post-treatment device 34, such as a drying device and/or a radiation device explained above. Alternatively, or additionally, the method may further comprise post-heating the adhesive by a post-heating device 36 and/or exposing the adhesive to moisture by a moisture regulator 39.

[0255] The method may further comprise applying pressure on the adhesive 20, preferably during curing or hardening of the adhesive. For example, a pressure device 35 such as those described in relation to FIGS. 1a and 3d may be used.

[0256] In some embodiments, the adhesive 20 may be pre-applied on the underlay element 23. For example, the underlay element may be delivered to the system 30 with a pre-applied adhesive. In such embodiments, such as in any of those in FIGS. 1a-1c, 2d, 3d, 4a-4f, 5a-5l, 7a-7c, the adhesive applier 40 applicator may become redundant, but other features may be the same. It is noted, however, that the pre-applied adhesive 20 may be embodied as in any of the embodiments described herein describing adhesive application on a board element 1, 1′ or an underlay element 23, 23a, 23b, such as in FIGS. 8a-8f and 9a-9b, 9d, 10a-10f. For example, the adhesive may be applied in a line application, a broad application, a pattern arrangement 26, etc.

[0257] As shown schematically in FIG. 7d, the underlay element with pre-applied adhesive may be provided with a release liner 29, such as a release film. The release liner may be removed before arranging the underlay element on the rear side 4, such as by a liner-removal device 38 provided in the system 30. In some embodiments, the release liner 29 may be removed in a continuous process, such as when the board element and/or the underlay element is fed along a feeding path FP, FP′, such as along a feeding direction FD, FD′.

[0258] The embodiment in FIG. 3e illustrates that the remaining portion 4b in any embodiment herein, such as in any of FIGS. 1a-1c, 2a-2e, 3a-3d, 4a-4f, 5a-5l, 7a-7d, 8a-8f, 9a-9b, 10c and 10e-10f, may comprise a surface roughness, e.g. comprising peaks 4e and valleys 4f. For example, the surface roughness may be provided by an embossing of the rear side 4. The peaks may be provided in the horizontal plane HP. The adhesive 20 attaching the underlay element 23 to the board element 1 may be provided on the peaks 4e, preferably such that no, or substantially no, adhesive is applied in the valleys 4f.

[0259] The inventive concept has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims and items in an embodiment section below. For instance, it is clear that the board element or panel in any of the embodiments in e.g. FIGS. 1a-1c, 2a-2e, 3c-3e, 4a-4b, 5a-5l, 7a-7d, 8a-8f and 9a-9b may comprise a layer arrangement 3 comprising at least one layer 3a, 3b, 3c in analogy with the discussion in relation to the embodiments in FIGS. 4a-4f. The at least one layer in the layer arrangement 3 may each comprise a polymer-based material, such as a thermoplastic material or a thermoset, and, preferably, a filler. Moreover, it is clear that any of the systems described herein, such as any of those in FIGS. 1a-1c, 2a-2e, 3a-3d, 5a-5l, 7a-7c and 9c-9f may comprise a post-treatment device 34, such as drying device, radiation device, or a moisture regulator 39, or a post-heating device 36. Optionally, the system may comprise a separation device 37. Finally, and as noted above, it is clear that in some embodiments the panel 1′, such as that in any of e.g. FIGS. 1a-1c, 2b-2d, 3c-3e, 4a-4b, 5a-5l, 7a-7c, 8a-8f, 9a-9b, 10c and 10e-10f, may instead be a building panel, wall panel, ceiling panel or furniture panel. Clearly, however, the panel 1′ in these embodiments may comprise a different locking system than that displayed in the figures or it may even be lacking a locking system.

Example 1

[0260] A layer of 20 g/m.sup.2 reactive PUR hot-melt Coating P. Materials PR-6620 was applied with a roll coater on the rear side of an SPC panel provided with a plurality of grooves. An EVA foam was arranged on the rear side of the panel such that the hot adhesive contacted the foam and the rear side. The panel was thereafter pressed in a calender press. A line-speed was set to 30 m/min and a calender pressure was set to 3 Bar. The adhesive was applied at an application temperature of 110° C., an ambient temperature of 25° C., and an RH value of 55%.

Example 2

[0261] A layer of 20 g/m.sup.2 reactive PUR hot-melt KLEIBERIT 711.2.00 was applied with a spray coater on the rear side of an LVT tile provided with a plurality of grooves. An IXPE foam was arranged on the rear side of the tile such that the hot adhesive contacted the foam and the rear side. The tile was thereafter pressed in a calender press. A line-speed was set to 15 m/min and a calender pressure was set to 3 Bar. The adhesive was 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%.

Embodiments

[0262] Further aspects of the inventive concept are provided below. Embodiments, examples etc. of these aspects are largely analogous to the embodiments, examples, etc. as described above, whereby reference is made to the above for a detailed description.

[0263] Item 1. A method for attaching an underlay element (23), such as an underlay unit (23a; 23b), to a board element (1), such as a panel (1′), comprising: [0264] providing a board element, wherein a rear side (4) of the board element comprises a groove portion (4a) and a remaining portion (4b), said groove portion comprising at least one groove (10), [0265] providing the underlay element (23), [0266] applying an adhesive (20) on at least a portion of said remaining portion (4b) and/or on at least a portion of a corresponding residual portion (21b) of the underlay element, and [0267] arranging the underlay element on the rear side of the board element, such that the adhesive contacts the underlay element and the rear side.

[0268] Item 2. The method according to item 1, wherein the adhesive is applied during a displacement of the board element and/or the underlay element along a feeding path (FP; FP′).

[0269] Item 3. The method according to item 1 or 2, wherein said arranging of the underlay element on the rear side is performed during a displacement of the board element and/or the underlay element in along a feeding path (FP; FP′).

[0270] Item 4. The method according to any of the preceding items, wherein the adhesive is applied at least on a peripheral portion (5) of the rear side and/or on a peripheral portion (5′) of an upper side of the underlay element, any or both of said peripheral portions preferably extending along a short edge portion (1c, 1d) and/or a long edge portion (1a, 1b) of the board element and/or the underlay element.

[0271] Item 5. The method according to item 4, wherein the peripheral portion of a board element comprises a peripheral portion (7) of at least one panel, such as at least two panels, into which the board element is configured to be divided and/or wherein the peripheral portion of an underlay element comprises a peripheral portion (7′) of at least one underlay unit, such as two underlay units, into which the underlay element is configured to be cut.

[0272] Item 6. The method according to any of the preceding items, wherein the method further comprises controlling said applying of the adhesive based on a characteristic of the at least one groove, wherein the controlling preferably results in adhesive being selectively applied, such as on the remaining portion and/or the corresponding residual portion.

[0273] Item 7. The method according to item 6, further comprising retrieving data about the characteristics of the at least one groove for controlling said applying of the adhesive.

[0274] Item 8. The method according to any of the preceding items, wherein the adhesive is applied by contact application, such as by slot-die coating or by roller coating and/or wherein the adhesive is applied by non-contact application, such as by spraying or curtain coating.

[0275] Item 9. The method according to any of the preceding items, wherein the adhesive is applied continuously or intermittently, such as along a feeding path (FP; FP′) of the board element and/or the underlay element.

[0276] Item 10. The method according to any of the preceding items, wherein the adhesive is applied in a pattern arrangement (26).

[0277] Item 11. The method according to any of the preceding items, wherein said remaining portion has a larger thickness (Tb) than a thickness (Ta) of said groove portion, a main portion of the remaining portion preferably having a constant thickness.

[0278] Item 12. The method according to any of the preceding items, wherein at least two grooves have been discontinuously formed, and wherein said applying of the adhesive comprises applying the adhesive between the discontinuous grooves, such as along a first (X) and/or a second (Y) horizontal direction of the board element.

[0279] Item 13. The method according to any of the preceding items, wherein the board element comprises at least one layer (3a, 3b, 3c) and wherein the at least one groove at least partly penetrates the at least one layer, such as at least a bottom layer (3c).

[0280] Item 14. The method according to item 13, wherein said at least one layer, optionally comprising a top layer (3a) and/or a bottom layer (3c), each comprises a polymer-based material, preferably a thermoplastic material or a thermoset, and, preferably, a filler.

[0281] Item 15. The method according to any of the preceding items, further comprising: [0282] cutting said underlay element (23) into at least one underlay unit (23a; 23b) along at least one cutting portion (12a).

[0283] Item 16. The method according to any of the preceding items, further comprising: [0284] dividing said board element (1) into at least one panel (V), such as at least two panels, along at least one dividing portion (12b).

[0285] Item 17. The method according to item 16, wherein the board element is divided after said act of arranging the underlay element on the rear side.

[0286] Item 18. The method according to any of the preceding items, further comprising controlling the applying of the adhesive such that no, or substantially no, adhesive is applied on a rear-side portion (4d) of the board element and/or an upper-side portion (21c) of the underlay element configured to be further processed, such as by cutting, dividing or forming of a locking system.

[0287] Item 19. The method according to any of the preceding items, further comprising controlling said applying of the adhesive such that no, or substantially no, adhesive is applied in at least one cutting portion (12a) and/or at least one dividing portion (12b).

[0288] Item 20. The method according to any of the preceding items, further comprising controlling said applying of the adhesive such that no, or substantially no, adhesive is applied: [0289] in a rear-side portion (4d) of where a locking system (9), such as of at least one panel (V), is configured to be formed, and/or [0290] in an upper-side portion (21c) of the at least one underlay unit (23a; 23b) configured to be provided along, such as to contact, said rear-side portion (4d).

[0291] Item 21. The method according to any of the preceding items, further comprising separating material elements (23c; 4c), such as chips, shavings or strips, removed from the underlay element and the board element during or after processing of the board element and the underlay element, such as by separating the material elements based on at least one attribute of the underlay element and the board element, respectively.

[0292] Item 22. The method according to item 21, wherein said processing comprises cutting said underlay element (23) into at least one underlay unit (23a; 23b) and dividing said board element into at least one panel and/or forming a locking system (9) on the board element.

[0293] Item 23. The method according to any of the preceding items, wherein the adhesive is a hot-melt adhesive.

[0294] Item 24. The method according to any of the preceding items, further comprising drying the adhesive and/or exposing the adhesive to radiation, such as infrared or ultraviolet radiation.

[0295] Item 25. The method according to any of the preceding items, further comprising post-heating the adhesive, i.e., heating the adhesive at or after its application on the rear side.

[0296] Item 26. The method according to any of the preceding items, further comprising applying pressure on the underlay element and/or the board element, preferably during curing or hardening of the adhesive.

[0297] Item 27. The method according to any of the preceding items, wherein the underlay element is a foam, such as a closed-cell foam, for example an IXPE foam, an IXPP foam, an EVA foam, an XLPO foam, an XLPE foam, a foam rubber or a PU, PO, PE or PS foam, or wherein the underlay element is a cork sheet.

[0298] Item 28. The method according to any of the preceding items, wherein the board element is a panel (1′) and wherein 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 portion of said panel, preferably on all edge portions (1a, 1b; 1c, 1d).

[0299] Item 29. The method according to any of the preceding items, wherein the panel is a floor panel or a wall panel.

[0300] Item 30. Board element (1), such as a panel (1′), obtainable by the method according to any of the preceding items 1-29.

[0301] Item 31. A system (30) for attaching an underlay element (23), such as an underlay unit (23a; 23b), to a board element (1), such as a panel (V), comprising: [0302] an adhesive applicator (40), and [0303] an underlay applier (31).

[0304] Item 32. Panel assembly comprising a panel (1′) and an underlay unit (23b), [0305] wherein a rear side (4) of the panel comprises a groove portion (4a) and a remaining portion (4b), said groove portion comprising at least one groove (10), and [0306] wherein the underlay unit (23b) is attached to the rear side of the panel by an adhesive (20) contacting at least a portion of said remaining portion and a corresponding residual portion (21b) of the underlay unit.

[0307] Item 33. The panel assembly according to item 32, wherein said remaining portion has a larger thickness (Tb) than a thickness (Ta) of said groove portion, a main portion of the remaining portion preferably having a constant thickness.

[0308] Item 34. The panel assembly according to item 32 or 33, wherein the adhesive is applied in a pattern arrangement (26).

[0309] Item 35. The panel assembly according to any of the preceding items 32-34, wherein at least two grooves have been discontinuously formed, and wherein the adhesive is provided between the discontinuous grooves, such as along a first (X) and/or a second (Y) horizontal direction of the panel.

[0310] Item 36. The panel assembly according to any of the preceding items 32-35, wherein the panel comprises at least one layer (3a, 3b, 3c) and wherein the at least one groove at least partly penetrates the at least one layer, such as at least a bottom layer (3c).

[0311] Item 37. The panel assembly according to item 36, wherein said at least one layer, optionally comprising a top layer (3a) and/or a bottom layer (3c), each comprises a polymer-based material, such as a thermoplastic material, and, preferably, a filler.

[0312] Item 38. A method for attaching an underlay element (23), such as an underlay unit (23a; 23b), to a board element (1), such as a panel (1′), comprising: [0313] providing a board element, wherein a rear side (4) of the board element comprises a groove portion (4a) and a remaining portion (4b), said groove portion comprising at least one groove (10), [0314] providing an underlay element (23) comprising a pre-applied adhesive (20), and [0315] arranging the underlay element on the rear side of the board element, such that the adhesive contacts the underlay element and the rear side.

[0316] Item 39. The method according to item 38, wherein the adhesive (20) is applied on at least a portion of a corresponding residual portion (21b) of the underlay element, such as on the corresponding residual portion only.

[0317] Item 40. The method according to item 38 or 39, further comprising synchronizing a position of the underlay element with a position of the board element, such that the underlay element becomes aligned with the board element, preferably such that a cover portion (21a) is aligned with the groove portion and a corresponding residual portion (21b) is aligned with the remaining portion.

[0318] Item 41. The method according to any of the preceding items 38 to 40, wherein the underlay element is provided with a release liner (29), such as a release film, and wherein the method further comprises removing the release liner before arranging the underlay element on the rear side.

[0319] Item 42. The method according to any of the preceding items 38 to 41, wherein no, or substantially no, pre-applied adhesive is applied on an upper-side portion (21c) of the underlay element configured to be further processed, such as by cutting or forming of a locking system.

[0320] Item 43. The method according to any of the preceding items 38 to 42, wherein no, or substantially no, pre-applied adhesive is applied in at least one cutting portion (12a).

[0321] Item 44. The method according to any of the preceding items 38 to 43, wherein no, or substantially no, pre-applied adhesive is applied in an upper-side portion (21c) of the at least one underlay unit (23a; 23b) configured to be provided along, such as to contact, a rear-side portion (4d) where a locking system (9), such as of at least one panel (V), is configured to be formed.

[0322] Item 45. The method according to any of the preceding items 38 to 44, and further according to any of the preceding items 3-5, 10-17, 21-29.