BUILDING PANEL COMPRISING MINERAL-BASED LAYER

Abstract

A panel, such as a floor panel, including a core, an optional upper arrangement and an optional lower arrangement. One or more of the core, the upper arrangement (5) and the lower arrangement includes a mineral-based layer, preferably including magnesium oxide. One or more of the mineral-based layers includes reinforcement fibres embedded in a mineral-based matrix, preferably including magnesium oxide. The fibres are configured to increase the tensile strength of the mineral-based layer.

Claims

1. A panel comprising a core, an optional upper arrangement and an optional lower arrangement, wherein one or more of the core, the upper arrangement and the lower arrangement comprises a mineral-based layer, wherein the mineral-based layer further comprises a polymer compound.

2. The panel according to claim 1, wherein the polymer compound comprises Acrylic, Styrene-Acrylic, Vinyl-acetate, Vinyl-Acetate-vinylchloride Styrene-Butadiene, vinylidene chloride or combinations thereof.

3. The panel according to claim 1, wherein the mineral-based layer comprises the polymer compound in an amount of 1 to 15 wt %.

4. The panel according to claim 1, wherein the polymer compound has a glass transition temperature, wherein the glass transition temperature of the polymer compound is in the range of −50 to 30° C.

5. The panel according to claim 1, wherein the mineral-based layer comprises magnesium oxide in the amount of 25 to 65 wt %.

6. The panel according to claim 1, wherein the mineral-based layer further comprises magnesium chloride and/or magnesium sulphate.

7. The panel according to claim 1, wherein the mineral-based layer further comprises at least one filler, in an amount of 0 to 50 wt %.

8. The panel according to claim 1, wherein the mineral-based layer further comprises a binding agent, in an amount of 0 to 30 wt %.

9. The panel according to claim 1, wherein the mineral-based layer further comprises at least one additive, in an amount of 0 to 20 wt %.

10. The panel according to claim 1, wherein one or more of said mineral-based layers comprises reinforcement fibres embedded in a mineral-based matrix, wherein the fibres are configured to increase the tensile strength of the mineral-based layer.

11. The panel according to claim 1, wherein the panel comprises a mechanical locking system at respective opposite first and second edges for assembling a first panel in an assembled position with an adjacent second panel by means of a folding displacement F and/or a vertical displacement of the adjacent panels; wherein immediately juxtaposed upper edge portions of the first edge of the first panel and the second edge of the second panel in the assembled position form a vertical plane; the first edge comprising a locking strip projecting beyond the vertical plane and a locking element projecting from the locking strip; the second edge comprising a downwards open locking groove configured to receive the locking element by means of said displacement for horizontal locking of the adjacent panels, wherein a first pair of horizontal locking surfaces comprises a first locking surface provided by the locking element and a second locking surface provided by the locking groove.

12. A method of producing a mineral-based layer, comprising mixing water, magnesium oxide, magnesium chloride or magnesium sulphate with a filler component to form a slurry; adding a polymer compound to said slurry; drying the slurry to form a layer.

13. The method according to claim 12, wherein the polymer compound is present in the amount 1 to 15 wt % of the mineral-based layer.

14. The method according to claim 12, wherein the polymer compound is added in the form of a powder or dispersed in water.

15. The method according to claim 12, wherein the polymer compound is added in the form of a dispersion, wherein the pH-value of the polymer dispersion is pH 7 or more.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0117] 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:

[0118] FIGS. 1a-1b schematically illustrate embodiments of a panel in a top view and in a bottom view.

[0119] FIG. 2a illustrates an embodiment of a panel in a cross-sectional view.

[0120] FIG. 2b illustrates an embodiment of a panel in a cross-sectional view.

[0121] FIG. 3 illustrates an embodiment of a panel in a cross-sectional view.

[0122] FIG. 4a illustrates an exemplary assembling process of a set of panels of FIG. 2a according to an embodiment.

[0123] FIG. 4b illustrates detail B of a folding displacement of the embodiment of FIG. 4a.

[0124] FIG. 4c illustrates of details of the embodiment of FIG. 4b in locking position.

[0125] FIG. 5a illustrates detail D of the embodiment of FIG. 4a.

[0126] FIG. 5b illustrates detail C of the embodiment of FIG. 4a.

[0127] FIG. 6a illustrates an exemplary assembling process of a set of panels according to the embodiment of FIG. 3.

[0128] FIG. 6b illustrates detail A of the embodiment of FIG. 6a.

[0129] FIG. 6c illustrates detail C of the embodiment of FIG. 6a.

[0130] FIG. 6d illustrates detail B of the embodiment of FIG. 6a.

[0131] FIG. 7a illustrates an exemplary assembling process of a set of panels of FIG. 2b according to an embodiment.

[0132] FIG. 7b illustrates detail N of a folding displacement of the embodiment of FIG. 7a.

[0133] FIG. 7c illustrates of details of the embodiment of FIG. 7a in locking position.

[0134] FIG. 8a is schematic illustration of an embodiment corresponding to FIG. 2a wherein the locking system is at least partially formed in a mineral-based layer.

[0135] FIG. 8b is schematic illustration of an embodiment corresponding to FIG. 2b wherein the locking system is at least partially formed in a mineral-based layer.

[0136] FIG. 8c is schematic illustration of an embodiment corresponding to FIG. 3 wherein the locking system is at least partially formed in a mineral-based layer.

[0137] FIGS. 9a-9b illustrates exemplary embodiments of the second aspect.

[0138] FIGS. 10a-10b illustrate exemplary embodiments of the third aspect.

[0139] FIG. 11a illustrates an embodiment according to the inventive concept.

[0140] FIG. 11b illustrates a further embodiment of the inventive concept.

[0141] FIG. 11c illustrates a still further embodiment according to the inventive concept.

DETAILED DESCRIPTION

[0142] Below, embodiments of the mineral-based panel 10 will mostly be described in the context of a floor panel, but it is understood that the panel also may be a building panel, a wall panel, a ceiling panel or a furniture panel.

[0143] FIG. 1a-1b show an exemplary panel according to the disclosure. Generally herein, the panel may extend in a first horizontal direction x and in a perpendicular second horizontal direction y. Moreover, the panel may extend in a vertical direction z which may be perpendicular to the first and second horizontal directions. The panel 1 may comprise a first pair of opposite edge portions 11, 12, which may be long edge portions, and a second pair of opposite edge portions 13, 14, which may be short edge portions. The long edge portions may extend along the first horizontal direction x and the short edge portions may extend along the second horizontal direction y.

[0144] The panel in any of the embodiments in FIGS. 1a-1b may comprise a locking system 50a on the first pair 11, 12 of opposite edge portions. The locking system may comprise a tongue 122 and a tongue groove 113 on the respective edge portion for vertical locking. For example, the tongue and tongue groove may be integrally formed with the panel. The locking system may further comprise a locking groove 123 and a locking element 114 on the respective edge portion for horizontal locking. The locking element is preferably provided on a strip 116 extending horizontally beyond an upper portion of the panel 10. It should be appreciated that the locking systems 50a may be provided at any pair of opposite edge portion, such as long edges and/or short edges.

[0145] The core 3 may be mineral-based and comprise reinforcing material, such as fibre reinforcement. The fibre reinforcement may be organic, such as comprising cellulose fibres or wood fibres, or inorganic, such as comprising glass fibres.

[0146] The mineral-based panel may further comprise a lower arrangement 6 comprising at least one lower layer which is attached to a lower side of the core 3. The lower arrangement may comprise a mineral-based layer.

[0147] The mineral-based panel may further comprise an upper arrangement 5 comprising at least one lower layer which is attached to a lower side of the mineral-based core. The upper arrangement may comprise a mineral-based layer.

[0148] The composition of the mineral-based layer of the lower arrangement may be the same or different as the composition of the mineral-based layer of the upper arrangement. Moreover, the composition of the mineral-based layer of the lower arrangement may be the same or different as the composition of a mineral-based core. Similarly, the composition of the mineral-based layer of the upper arrangement may be the same or different as the composition of a mineral-based core.

[0149] The locking system 50a, 50b may be at least partially formed in the core 3 between the upper arrangement 5 and the lower arrangement 6, as shown in FIGS. 2a-2b and 3. In particular, a first and second pair of horizontal locking surfaces 111, 121 and 125, 115, respectively, may be formed in the core 3, for example by means of machining, such as rotating tools. Alternatively or additionally, at least part of the locking system 50a, 50b may be formed in a mineral-based layer of the upper arrangement 5 and the lower arrangement 6, as schematically shown in the embodiments of FIGS. 8a-8c. In particular, the second pair of horizontal locking surfaces 125, 115 may be formed in such mineral-based layer. For example, a portion of the locking strip 116 including the upper surface 118 of the locking strip and the locking element 114 may be formed in a mineral-based layer, such as the core or a mineral-based layer of the lower-arrangement 6. For example, the first locking tongue 122 and the first tongue groove 113 may be formed in a mineral-based layer, such as the core 3 or a mineral-based layer of the upper-arrangement 5. In a still further example, the second tongue groove 138 and at least part of the displacement groove 142 may be formed in a mineral-based layer, such as the core 3 or a mineral-based layer of the upper-arrangement 5.

[0150] Alternatively, or additionally, any of the panels in FIGS. 1a-1b may comprise a locking system 50b on the second pair 13, 14 of opposite edge portions. The locking system may comprise a tongue 142 and a tongue groove 138 on the respective edge portion for vertical locking. For example, and as shown in FIG. 6b, the tongue 148 may be a separate locking tongue 148 provided in a displacement groove 142, preferably providing a fold down locking system. The locking system 50b may be configured for assembling of panels by means of a folding displacement and/or a vertical displacement. FIG. 6b shows a folding displacement. A non-limiting embodiment of a separate locking tongue 142 is illustrated in FIG. 6b in a cross-sectional top view. This so-called bristle tongue is preferably formed in one-piece and comprises flexible protrusions. The locking system 50b may further comprise a locking groove 133 and a locking element 144 on the respective edge portion for horizontal locking. The locking element is preferably provided on a strip 146 extending horizontally beyond an upper edge portion 141 of the fourth edge of the panel 10. The locking groove 133 is preferably provided inboard of an upper edge portion 131 of the third edge 13 of the panel 10. Thus, it should be appreciated that the locking systems 50b may be provided at any pair of opposite edge portion, such as long edges and/or short edges.

[0151] Any horizontal locking system may comprise a locking element and a locking groove, and/or any vertical locking system may comprise a tongue and a tongue groove. Alternatively, or additionally, the locking element and locking groove may comprise vertical locking surfaces configured to cooperate for vertical locking. In a first example, the tongue is integrally formed with the panel, preferably with the core. This is conceivable on a long and/or a short edge portion. In a second example, and as preferred on a short edge portion, the tongue is separately formed from the panel, and may be provided in a displacement groove 142 provided in the panel, preferably in the core 3.

[0152] A horizontal extension of the tongue 122, 148 from a vertical plane VP may be smaller than an extension of the strip 116, 146 from a vertical plane VP. A horizontal extension of the respective tongue groove 113, 138 may be substantially the same as the extension of the respective tongue 122, 148.

[0153] Referring to FIGS. 2a-2b and 3 there is illustrated exemplary embodiments of a panel 10 according to the disclosure. The panel comprises a mineral-based core 3, preferably comprising magnesium oxide, as has been explained herein.

[0154] The panel comprises a mechanical locking system, such as 50a or 50b at respective opposite first 11 and second 12 edges, such as long edges, for assembling a first panel 10 in an assembled position with an adjacent second panel 20 by means of a folding F displacement, as illustrated in FIG. 4a-4c.

[0155] The first edge 11 may comprise the locking strip 116 projecting beyond the vertical plane VP.

[0156] As illustrated e.g. in FIG. 4c, the strip 116 may extend from vertical plane VP defined by immediately juxtaposed upper portions 111, 121 of two neighboring joint edge portions of two joined panels, such as the first edge 11 of the first panel 10 and the second edge 22 of the second panel 20. The strip may be a strip at a short edge portion and/or at a long edge portion. Optionally, the strip may comprise a lower panel portion provided below the tongue groove.

[0157] The horizontal portion may extend along a first and/or a second horizontal direction of the mineral-based panel and may have a vertical extension, such as extending from a rear side 16 of the panel to an upper surface of the strip 118, 143.

[0158] The strip 116 may comprise a locking element 114, 144. Preferably, the horizontal portion is at least provided horizontally inwardly of the locking element.

[0159] The horizontal portion may comprise the entire strip, preferably including a locking element.

[0160] The locking element 114 may comprise a portion of the mineral-based core, such as at a distal end portion of the locking element. The distal end portion may be a vertical distal end portion.

[0161] A horizontal and/or a vertical locking surface may be provided in the core 3.

[0162] The strip may extend horizontally beyond an upper portion 111, 112 of the mineral-based panel.

[0163] At least a horizontal portion of the strip may be formed in the core 3.

[0164] A locking element 114 projects from the locking strip 116, such as in a direction perpendicular the locking strip 116.

[0165] The horizontal portion may at least be provided horizontally inwardly of the locking element 114.

[0166] The horizontal portion may comprise the entire strip, preferably including the locking element 114.

[0167] The second edge 12 comprises a downwards open locking groove 123 configured to receive the locking element 114 by means of said displacement for horizontal locking of the adjacent panels.

[0168] Generally, a locking surface may be configured to lock two adjacent panels in one direction. Therefore, the horizontal and vertical locking system preferably comprises at least a pair of horizontal locking surfaces and at least a pair of vertical locking surfaces be configured to lock two adjacent panels in two opposite horizontal and vertical directions, respectively. In some embodiments, the horizontal and vertical locking surfaces may be provided by a common, preferably inclined, surface.

[0169] In the locking systems 50a, 50b, a respective first pair of horizontal locking surfaces 115, 125 and 145, 134 comprises a first locking surface 115, 145 provided by the locking element 114, 144 a second locking surface 125, 134 provided by the locking groove 123, 133.

[0170] A respective second pair of horizontal locking surfaces 111, 121 and 131, 141 comprises an upper edge portion 111, 131 of the first or third edge and an upper edge portion 121, 141 of the second edge 12 and fourth edge 14.

[0171] In the embodiment of FIGS. 2 and 4b, a first pair of vertical locking surfaces may comprise an upper surface portion 126 of the locking tongue 122 and an upper wall surface portion 117 of the tongue groove 113.

[0172] In the embodiment of FIGS. 3 and 6b, a first pair of vertical locking surfaces may comprise a lower surface portion 149 of the locking tongue 148 and a lower wall surface portion 137 of the tongue groove 138.

[0173] A second pair of vertical locking surfaces may comprise lower surfaces 124, 135 of the first edge 11 and third edge 13 respectively and upper surfaces 118, 143 of the locking strips 116, 146.

[0174] As shown in FIGS. 4b and 6b, a first contact point P1 may be defined in the locking system 50a as between the second pair of horizontal locking surfaces, such as an upper edge portion 111 of the first edge 11 of the first panel 10 and an upper edge portion 121 of the of the second panel 20. Alternatively, between the second pair of horizontal locking surfaces of locking system 50b, such as an upper edge portion 141 of the fourth edge 14 of the first panel 10 and an upper edge portion 131 of the of the third edge 23 of a second panel 20.

[0175] A second contact point P2 may be defined in the locking system 50a or 50b as between the first pair of vertical locking surfaces 117, 126 and 149, 137 respectively, such as a surface of an upper wall portion 117 of the tongue groove 123 of the first panel 10 and an upper surface portion 126 of the locking tongue 122 of the second panel 20.

[0176] Referring to FIGS. 7a-7c, the first edge 11 may comprise a lower lip surface 150 provided between the upper edge portion 111 and the tongue groove 113. The lower lip surface 150 may extend essentially parallel the upper wall surface portion 117 and/or essentially perpendicular the upper edge portion 111.

[0177] Further to FIGS. 7a-7c, the second edge 12, 22 of the panel 10 and 20 respectively, may in any embodiment comprise an upper lip surface 151 configured to abut the lower lip surface 150 when two panels are assembled in locking position, as shown in FIG. 7c. The lower lip portion 151 may be provided between the upper edge portion 121 and the locking tongue 122. The lower lip portion 151 may extend essentially parallel the upper surface portion 126 of the locking tongue 122 and/or essentially perpendicular the upper edge portion 121. It should be appreciated that any of the opposite edge portions 11-14 may comprise such cooperating upper- and lower lip portions, not limited to edge portions comprising the first locking system 50a but also including edge portions comprising the second locking system 50b.

[0178] A third contact point P3 may be defined as between the upper lip portion 151 and the lower lip portion 150.

[0179] According to a preferred embodiment, a locking angle LA may be adapted to allow the folding displacement without overlapping of the first locking surface 115 and the second locking surface 125, for example while P1 is simultaneously in contact, more preferably while P1 and P2 are simultaneously in contact. Optionally P3 is simultaneously in contact. The term “overlapping” may in this context refer to engagement between the first locking surface 115 and the second locking surface 125.

[0180] FIGS. 3 and 6b illustrates an exemplary embodiment of the second locking system 50b which may be provided at respective opposite third 13 and fourth 14 edges, such as short edges, for assembling a first panel in an assembled position with an adjacent second panel by means of a folding displacement F or a vertical displacement of the adjacent panel, such as a linearly vertical displacement.

[0181] As shown in the embodiment of FIG. 6b, the second contact point P2 may be defined as between the surface portion of the lower wall portion 137 of the tongue groove 138 of the second panel 20 and a lower surface portion 149 of the locking tongue 148 of the first panel 10.

[0182] The locking system 50a may be configured such that the first and second locking surfaces 115, 125 do not overlap during assembling of the first and second panel and, preferably such that there is provided play Dt (see FIG. 5b) between the first and second locking surfaces 115, 125 of the first pair of horizontal locking surfaces in assembled position of the first and second panels 10, 20.

[0183] Referring again to FIGS. 5b and 6d, the locking angle LA may be formed between the second locking element and the rear surface 16 of the panel. The locking angle LA may be measured in a clockwise angular direction in FIG. 6d. The locking angle LA may preferably be in the range of 40 to 50 degrees, preferably 45 to 55 degrees, more preferably 48 to 52 degrees, such as 50 degrees.

[0184] The second locking surface 125 may be configured to extend essentially parallel the first locking surface 115 in assembled position of the panels, as derivable from FIG. 6d.

[0185] The locking system 50a and preferably 50b may be configured such that in assembled position of the first and second panels 10, 20, there is provided a play Dt (see FIGS. 5b and 6d) between the first pair of horizontal locking surfaces, preferably 0 to 0.1 mm play.

[0186] The play Dt may be provided along a substantial portion of the locking surfaces 115, 125 and/or 132, 145.

[0187] The locking angle LA may be adapted to allow the folding displacement without abutment of the first locking surface 115 and the second locking surface 125.

[0188] Generally, in any embodiment, the locking angle LA may be configured to allow assembling by means of the folding displacement without flexing or compression of any part of the locking system 50a, 50b, excepting the displaceable tongue 148, which may be displaced into the displacement groove 142 by, for example, flexing of flexible protrusions on the tongue 148. The displaceable tongue 148 may be configured to flex and/or displace into the displacement groove 142 to an extent which suffice for allowing the panels to be assembled exclusively by means of a substantially vertical displacement VF.

[0189] Accordingly, the locking angle LA may be adapted to allow assembling by means of the folding displacement without flexing or compression of the locking strip 116.

[0190] Accordingly, the locking angle LA may be adapted to allow assembling by means of the folding displacement without flexing or compression of the second edge 22 of the second panel.

[0191] The locking angle LA may be adapted to allow assembling by means of the folding displacement without flexing or compression of the locking element 114.

[0192] The locking strip 116 may be formed in the core 3, preferably the entire locking strip 116 is formed in the core 3, thus the core material, such as MgO, may extend continuously from the tongue groove 113 or displacement groove 112 to and including the locking element 114. The locking element 114 may thus preferably be formed in the core 3.

[0193] The locking element 114 may be formed as an integral part of the locking strip 116.

[0194] The plane of the first horizontal locking surface 115 of the first panel 10 may define a datum plane Dm.

[0195] As shown in FIGS. 5a-5b, according to any embodiment, there may be provided a minimum play Da between the first locking surface 115 and the second locking surface 125 during assembling (see FIG. 5a) of the first and second panel to the locking position (see FIG. 5b). The play Da between the first pair of horizontal locking surfaces may be in the range of more than 0 to 0.1 mm.

[0196] In one embodiment there may be zero or least no negative play between the first pair of horizontal locking surfaces 115, 125 during assembling, such as during displacement from the first position to the second assembled positon.

[0197] As shown for example in FIGS. 5a-5b, according to any embodiment, the play Da between the first locking surface 115, 145 and the second locking surface 125, 134 during assembling (see FIG. 5a) may be a minimum play between the first locking surface 115 and the second locking surface 125 during assembling of the first and second panel to the locking position (see FIG. 5b). The play Da may be in the range of 0 to 0.1 mm.

[0198] Preferably, there is provided play between the first locking surface 115 and the second locking surface 125 during assembling of the first and second panel to the locking position.

[0199] Referring to FIG. 5a, a point P on the said portion of the second horizontal locking surface 125 may be positioned at a first space position P0, such as when P1 and optionally P2 are in contact, as shown in FIG. 4b. By means of the folding displacement F, such as of the second panel 20, preferably about the second edge 22 of the second panel 20, the point P may displace according to a projected trajectory Tp to a second space position P0′, as illustrated in FIG. 5a-5b.

[0200] Thus, when point P is positioned in the first position P0, a projected trajectory Tp of point P from the first position P0 to the second position P0′ may form an arc of a circle, preferably having as P1 as pivotal point and with radius of curvature R1.

[0201] The projected trajectory Tp may be one or more of a projected trajectory and a predetermined trajectory.

[0202] The locking angle LA and optionally Dt may be configured such that the said projected trajectory does not cross the plane Dm during assembling of the first and second panel 10, 20 to the locking position by means of the folding displacement F, preferably while there is contact at contact point P1 and/or P2. In particular, the locking angle LA and optionally Dt is configured such that the projected trajectory Tp does not cross from one side of the plane Dm, such as an upper side, to the other side of the plane Dm, such as a lower side during said assembling by means of the folding displacement F. It should be appreciated that the above may be valid without flexing of any of the parts of the locking system 50a, 50b. Thus, point P may preferably displace along the projected trajectory from P0 to P0′ without influence of the locking element 114 and in particular without influence of the first locking surface 115.

[0203] Thereby, a projected trajectory Tp of point P of the locking surface 125 from position P0 to position P0′ in response to a folding displacement F of the second panel 20, such as about the second edge 22 of the second panel 20, may be disposed on one side, preferably entirely on one side, of the first locking surface 115 and/or a datum plane Dm of the first locking surface 115 during the folding displacement F while at least one of points P1, P2 and P3 are in contact. The datum plane Dm may be stationary.

[0204] Assembling of the first and second panel 10, 20 may herein comprise a displacement in an assembling direction from a first position wherein the adjacent edges 11, 12; 13; 14 are in contact in point P1, to a second assembled position for horizontal locking of the adjacent edges by means of the first locking surface 115 and the second locking surface 125. For example the first position may be where point P of the second locking surface 125 is in space position P0 and the second assembled position may be where point P is arranged in space position P0′ as shown in FIG. 5b.

[0205] Accordingly, in any embodiment, the distance between the pivot point, such as the first contact point P1 and a point on the first locking surface 115 may be constant during assembling by means of the folding displacement F.

[0206] A shortest distance D1 between a pivot point, such as contact point P1, of the panel being folded, and the first locking surface 115 may be greater than a greatest distance D2 between the said pivot point and the second locking surface 125 as shown in FIG. 5b. Thus, considering point P on the second locking surface 125, which may be any given point of the second locking surface 125. D2 may correspond to radius of curvature R1.

[0207] Referring again to FIGS. 9a-9b and 11a-11c, there is illustrated exemplary embodiments of the second aspect.

[0208] The panel 10, such as a floor panel, comprises a core 3 and may comprise an upper arrangement 5 and a lower arrangement 6. The panel comprises one or more mineral-based layers, as explained in relation to the first aspect. Thus, one or more of the core 3, the upper arrangement 5 and the lower arrangement 6 may comprise a mineral-based layer 3, 5, 6, preferably comprising magnesium oxide. According to the second aspect, one or more of said mineral-based layers comprises reinforcement fibres 50 embedded in a mineral-based matrix 51, the matrix 51 preferably comprising magnesium oxide. The fibres 50 may be configured to increase the tensile strength of the mineral-based layer 3, 5, 6.

[0209] A mineral-based layer, such as an MgO layer, may have many different compositions depending on the required properties. The layer is typically produced by creating a slurry in water and then pouring the slurry into moulds. The slurry will then dry and become rigid, thereby forming a board that will make a mineral-based layer in a building panel. A typical drawback of mineral-based boards may include that they absorb water, are very brittle and hard to profile using e.g. rotating tools to form a mechanical locking system along the edges. However, advantages include that mineral-based layers are dimensionally stable and have fire-retardant properties.

[0210] According to the second aspect, reinforcement fibres 50, such as long fibres, are provided in the inorganic matrix 51 (MgO/MgSO.sub.4) as shown for instance in FIGS. 9a-9b. The fibres may preferably be arranged in the matrix prior to a step of drying of the mineral-based layer.

[0211] The fibers 50 are preferably longer than the traditional wood fibers that are used in known systems and can be of inorganic or inorganic material. Thereby, in contrast to a mineral-based layer with short wood fibers, the board according to the invention with long fibers may withstand more bending forces and are less brittle, thus these properties render them more suitable and easier to form a mechanical locking system therein, such as a mechanical locking system 50a, 50b according to the first aspect.

[0212] An aspect ratio (length-to-diameter) of the fibres 50 may be in the range of between 30 to 150. Preferably, for concrete, the aspect ratio should preferably be above 75. A thin and short fibre may only have a limited effect when for example hardening the cement/matrix but will not increase the tensile strength. Fibers with low E-module, such as nylon and PP may facilitate increased toughness of the layer. Fibres with high modulus, such as glass, carbon and steel fibre may facilitate increased strength of the layer.

[0213] As briefly discussed, the fibres 50 may comprise organic fibres, such as synthetic fibers, such as polypropylene fibre, such as fibres sold under the trade name Masterfiber 246, plolyvinylalchohol fibre, for example sold under the trade name Masterfiber 400, Polyester fibre, nylon fibre or combinations thereof.

[0214] An aspect ratio of the synthetic fibres, such as length divided by diameter, preferably an average aspect ratio, may be in the range of 25 to 700, more preferably 75 to 300.

[0215] The fibres 50 may comprise organic fibres, such as natural fibers, such as flax, hemp, bamboo, cotton, wood, sisal, jute, ramie, or combinations thereof.

[0216] The aspect ratio of the natural fibres, such as length divided by diameter, preferably an average aspect ratio of the fibres, may be in the range of 25 to 700, more preferably 100 to 400.

[0217] The fibres 50 may comprise inorganic fibers such as glass fibres, carbon fibres, steel fibres or combinations thereof.

[0218] The fibres 50 may comprise a mix of any of the organic and any of the inorganic fibers described herein.

[0219] The aspect ratio of the inorganic fibres, such as length divided by diameter, preferably an average aspect ratio of the fibres, may be in the range of 50 to 2000, more preferably 75 to 1000.

[0220] In any embodiment, the length of the fibres, such as an average length, is in the range of 3 to 50 mm, more preferably 3 to 25 mm.

[0221] In any embodiment, the volume % of fibres in the mineral based layer comprising fibres may be in the range of 0.1% to 7%, more preferably 1% to 4%.

[0222] In any embodiment, the fibres may be provided in form of non-woven fibres. For example the fibers may be randomly oriented and/or randomly distributed individual fibers. For example the fibers may be non-woven non-unidirectional fibres.

[0223] The fibres may be distributed between an upper surface of the mineral-based layer and a lower surface of the mineral-based layer, such as between an upper surface of the core 3a and a lower surface of the core 3b. The fibres may preferably be substantially evenly or uniformly distributed in the thickness direction of the mineral-based layer between the upper surface of the mineral-based layer and the lower surface of the mineral-based layer.

[0224] The fibres may be configured to extend in the matrix or layer with a longitudinal axis of the fibres oriented essentially parallel the plane of the panel, such as a horizontal plane H or a lower surface 16 of the core as derivable e.g. from FIG. 2a.

[0225] FIGS. 10a-10b and 11a-11c illustrate exemplary embodiments of a third aspect. According to embodiments of the third aspect, the mineral-based layer comprises additives which makes the brittle and rigid matrix, such as MgO inorganic matrix (MgO/MgSO.sub.4), more flexible. An effect of providing a polymer compound may be facilitation of a more flexible and/or water-resistant mineral-based layer. A more flexible mineral-based layer may facilitate ease of profiling a mechanical locking system, such as by means of rotating tool(-s), and may optionally or additionally provide a more flexible mechanical locking system, thereby reducing the risk of damaging the panel and/or the locking system, such as during assembling. The polymer may preferably be added during the production of MgO boards when mixing the components making up the board.

[0226] The polymer component may be provided as a dispersion (polymer “droplets” dispersed in water) or a dispersible powder. Thereby, the polymers will be situated between and around the inorganic material, such as MgO, and thus facilitate softening of the inorganic material and thus a flexible mineral-based layer compared to for example MgO without the addition of polymers. The polymer component should preferably have a low glass transition temperature Tg(° C.) for example below 30° C. preferably below 0° C., more preferably −10 to 20° C.

[0227] The polymer component may be based on the following chemistries: Acrylic, Styrene-Acrylic, Vinyl-acetate, Vinyl-Acetate-vinylchloride Styrene-Butadiene, vinylidene chloride.

[0228] The polymer compound may be added in an amount of 1 to 15 wt %, more preferably 5 to 10 wt % of the mineral-based layer.

[0229] The polymer compound may contribute to improved adhesion between the mineral-based layer and adjacent layers when used in mortars. The polymer compound may also improve the adhesion of glue when adhering of the mineral-based layer to an adjacent layer, such as adhering an upper and/or lower arrangement to a mineral-based core.

[0230] It should be emphasized that FIGS. 9a-9b, 10a-10b and 11a-11c show non-limiting exemplary embodiments and that combination of embodiments of the first aspect, the second aspect and the third aspect may yield further embodiments. For example, the embodiments shown in FIGS. FIGS. 9a-9b, 10a-10b and 11a-11c features the locking system 50a for purpose of conveying the invention and should not be construed as limiting the invention to the illustrated embodiments shown therein. In a further example, fibres 50 may be embedded in the core 3 and a polymer compound may or may not be provided in the matrix 51 of a mineral-based layer of the upper- and/or lower arrangement. In a still further example, fibres 50 may be embedded in a mineral-based layer of the upper- and/or lower arrangement and a polymer compound 60 may or may not be provided in the matrix 51 of a mineral-based the core 3.

[0231] Referring again to FIG. 9a, an exemplary embodiment of a panel 10 is shown wherein the mineral-based core 3 comprises fibers 50 according to any embodiment of the disclosure embedded in the matrix 51. At least parts of the mechanical locking system 50a are formed in the core 3, including the locking strip 116 and the locking element 114 at the first edge 11, the locking tongue 122 and the locking groove 123 at the second edge 12. It should be appreciated that at least parts of the second locking system 5b may be formed in the core 3, such as at least a portion of the second locking strip 146. The fibers 50 preferably configured to increase the tensile strength of the mineral-based layer 3 compared to a mineral-based layer without the fibers and/or render parts of the locking system 50a formed in the mineral-based layer(s) more flexible and/or less brittle compared to a mineral-based layer without the fibers.

[0232] In the exemplary embodiment of FIG. 9b the panel 10 also comprises a core 3 according to any embodiment of the core 3 disclosed herein, such as a wood-based core. The lower arrangement 6 and optionally the upper arrangement 5 comprises a mineral-based layer according to any embodiment of the disclosure and fibers 50 according to any embodiment of the disclosure embedded in the matrix 51 during manufacture of the mineral-based layer. At least parts of the mechanical locking system 50a are formed in a mineral-based layer, such as a mineral-based layer of the lower arrangement 6, including at least a portion of the locking strip 116 and the locking element 114 at the first edge 11. It should be appreciated that at least parts of the second locking system 5b may be formed in the core 3, such as at least a portion of the second locking strip 146. The fibers 50 preferably configured to increase the tensile strength of the mineral-based layers 5, 6 compared to a mineral-based layer without the fibers and/or render parts of the locking system 50a formed in the mineral-based layer(s) more flexible and/or less brittle compared to a mineral-based layer without the fibers.

[0233] FIG. 10a shows an exemplary embodiment of a panel 10 wherein a mineral-based core 3 according to any embodiment comprises a polymer compound 60 according to any embodiment of the disclosure. At least parts of the mechanical locking system are formed in the core 3, such as at least a portion of the locking strip 116 and the locking element 114 at the first edge 11, at least a portion of the locking tongue 122 and at least a portion of the locking groove 123 at the second edge 12. The polymer compound may preferably be configured to render the panel 10 and/or said parts of the locking system 50a formed in the core 3, such as the locking strip 116 and/or locking tongue 122, softer and/or more flexible compared to a mineral-based layer without the polymer compound.

[0234] Referring again to FIG. 10b, an exemplary embodiment of a panel 10 is shown comprising a core 3 according to any embodiment of the core 3 disclosed herein, such as a wood-based core. The lower arrangement 6 and optionally the upper arrangement 5 comprises a mineral-based layer. The mineral-based layer comprises a polymer compound according to any embodiment of the disclosure, such as embedded in the matrix 51 during manufacture of the mineral-based layer. At least parts of the mechanical locking system are formed in a mineral-based layer, such as a mineral-based layer of the lower arrangement 6, such as at least part of the locking strip 116 and the locking element 114 at the first edge 11 and at least part of the locking groove 123 at the second edge 12. The polymer compound 60 may preferably be configured to render the panel 10 and/or said parts of the locking system 50a formed in the mineral-based layer, such as the locking strip 116 and/or locking tongue 122, softer and/or more flexible compared to a mineral-based layer without the polymer compound, and/or less brittle.

[0235] FIG. 11a shows an exemplary embodiment of a panel 10 wherein the mineral-based core 3 comprises a polymer compound 60 according to any embodiment of the disclosure, such as embedded in the matrix 51, for example the polymer compound 60 is configured to render the panel 10 more flexible.

[0236] The mineral-based core 3 additionally comprises fibers 50 according to any embodiment of the disclosure embedded in the matrix 51.

[0237] At least parts of the mechanical locking system are formed in the core 3, including the locking strip 116 and the locking element 114 at the first edge 11, the locking tongue 122 and the locking groove 123 at the second edge 12. The polymer compound 50 may preferably be configured to render one or more of the panel 10 and parts of the locking system 50a formed in the mineral-based layer(s), for example the locking strip 116, softer and/or more flexible, compared to a mineral-based layer without the polymer compound. The fibers 50 preferably configured to increase the tensile strength of the mineral-based layer 3 compared to a mineral-based layer without the fibers and/or render parts of the locking system 50a formed in the mineral-based layer(s) more flexible and/or less brittle compared to a mineral-based layer without the fibers, such as the locking strip 116 and/or locking tongue 122.

[0238] In the exemplary embodiment of FIG. 11b the panel 10 also comprises a core 3 according to any embodiment of the core 3 disclosed herein, such as a wood-based core. The lower arrangement 6 and optionally the upper arrangement 5 comprises a mineral-based layer according to any embodiment of the disclosure and fibers 50 according to any embodiment of the disclosure embedded in the matrix 51. In addition, the matrix 51 of the mineral-based layer of the upper arrangement 5 and/or the matrix 51 of the mineral-based layer of the lower arrangement 6 comprises a polymer compound 60 according to any embodiment of the disclosure. The polymer compound 50 may preferably be configured to render one or more of the panel 10 and parts of the locking system 50a formed in the mineral-based layer(s) softer and/or more flexible, compared to a mineral-based layer without the polymer compound, for example the locking strip 116. The fibers 50 preferably configured to increase the tensile strength of the mineral-based layers 5, 6 compared to a mineral-based layer without the fibers and/or render parts of the locking system 50a formed in the mineral-based layer(s) more flexible and/or less brittle compared to a mineral-based layer without the fibers.

[0239] In the exemplary embodiment of FIG. 11c there is shown a panel 10 having a mineral-based core 3 comprising a polymer compound 60 and fibers 50 according to any embodiment of the disclosure. The upper arrangement 5 and the lower arrangement 6 comprises a mineral-based layer comprising in the matrix 51 a polymer compound 60 and fibers 50 according to any embodiment of the disclosure the matrix 51. The polymer compound 50 may preferably be configured to render one or more of the panel 10 and parts of the locking system 50a formed in the mineral-based layer(s) softer and/or more flexible compared to a mineral-based layer without the polymer compound, for example the locking strip 116. The fibers 50 preferably configured to increase the tensile strength of the mineral-based layers 3, 5, 6 compared to a mineral-based layer without the fibers and/or render parts of the locking system 50a formed in the mineral-based layer(s) more flexible and/or less brittle compared to a mineral-based layer without the fibers.

[0240] Accordingly, a panel in which one or more mineral-based layers 3, 5, 6 comprises fibers 50 and/or the polymer compound 60 may be particularly advantageous in combination with embodiments of the locking system 50a configured to reduce or circumcise flexing of at least the said parts formed in the one or more mineral-based layers, wherein at least parts of the mechanical locking system 50a is formed in a mineral-based layer 3, 5, 6.

Items

[0241] ITEM 1. A panel 10, such as a floor panel, comprising a core 3, an optional upper arrangement 5 and an optional lower arrangement 6, wherein one or more of the core 3, the upper arrangement 5 and the lower arrangement 6 comprises a mineral-based layer, preferably comprising magnesium oxide.

[0242] ITEM 2. The panel according to item 1, wherein one or more of said mineral-based layers comprises reinforcement fibres 50 embedded in a mineral-based matrix 51, preferably comprising magnesium oxide, wherein the fibres are configured to increase the tensile strength of the mineral-based layer.

[0243] ITEM 3. The panel according to item 2, wherein the fibres comprise organic fibres, such as synthetic fibers, such as Polypropylene fibre, Plolyvinylalchohol fibre, Polyester fibre, Nylon fibre or combinations thereof.

[0244] ITEM 4. The panel according to any one of the preceding items 2 to 3, wherein the aspect ratio, such as an average aspect ratio, such as length divided by diameter, of the fibres is in the range of 25 to 700, more preferably 75 to 300.

[0245] ITEM 5. The panel according to item 2, wherein the fibres comprise organic fibres, such as natural fibers, such as flax, hemp, bamboo, cotton, wood, sisal, jute, ramie, or combinations thereof.

[0246] ITEM 6. The panel according to item 5, wherein the aspect ratio, such as an average aspect ratio, such as length divided by diameter, of the fibres is in the range of 25 to 700, more preferably 100 to 400.

[0247] ITEM 7. The panel according to item 2, wherein the fibres comprise inorganic fibers such as glass fibres, carbon fibres, steel fibres or combinations thereof.

[0248] ITEM 8. The panel according to item 7, wherein the aspect ratio, such as an average aspect ratio, such as length divided by diameter, of the fibres is in the range of 50 to 2000, more preferably 75 to 1000.

[0249] ITEM 9. The panel according to any one of the preceding items 2 to 8, wherein the length of the fibres, such as an average length, is in the range of 3 to 50 mm, more preferably 3 to 25 mm.

[0250] ITEM 10. The panel according to any one of the preceding items 2 to 9, wherein the volume % of fibres in the mineral based layer comprising fibres is in the range of 0.1% to 7%, more preferably 1% to 4%.

[0251] ITEM 11. The panel according to any one of the preceding items 2 to 10, wherein the fibres are provided in shape of non-woven fibres.

[0252] ITEM 12. The panel according to any one of the preceding items 2 to 11, wherein the fibres are arranged in the matrix prior to a step of drying of the mineral-based layer.

[0253] ITEM 13. The panel according to any one of the preceding items 2 to 12, wherein the fibres are distributed between an upper surface of the mineral-based layer and a lower surface of the mineral-based layer, such as between an upper surface 3a of the core and a lower surface 3b of the core.

[0254] ITEM 14. The panel according to any one of the preceding items 2 to 13, wherein the fibres are oriented to extend essentially parallel the plane of the panel, such as a horizontal plane H or a lower surface 16 of the core.

[0255] ITEM 15. The panel according to any of the preceding items 1 to 14, wherein the mineral-based layer 3, 5, 6 further comprises a polymer compound.

[0256] ITEM 16. The panel according to item 15, wherein the polymer compound comprises Acrylic, Styrene-Acrylic, Vinyl-acetate, Vinyl-Acetate-vinylchloride, Styrene-Butadiene, vinylidene chloride or combinations thereof.

[0257] ITEM 17. The panel according to any of the preceding items 15 to 16, wherein the mineral-based layer comprises the polymer compound in an amount of 1 to 15 wt %, more preferably 5 to 10 wt %.

[0258] ITEM 18. The panel according to any of the preceding items 15 to 17, wherein the polymer compound has a glass transition temperature, and the glass transition temperature of the polymer compound is in the range of −50 to 30° C., more preferably −10 to 20° C.

[0259] ITEM 19. The panel according to any one of the preceding items 1 to 18, wherein the mineral-based layer further comprises magnesium chloride and/or magnesium sulphate.

[0260] ITEM 20. The panel according to any one of the preceding items 1 to 19, wherein the mineral-based layer further comprises at least one filler, such as Perlite, Sand, Talc, Fly ash, Calcium Carbonate or combinations thereof in an amount of 0 to 50 wt %, such as 10 to 40 wt %.

[0261] ITEM 21. The panel according to any one of the preceding items 1 to 20, wherein the mineral-based layer further comprises a binding agent, such as wood shavings or wood fibres, in an amount of 0 to 30 wt %, such as 5 to 25 wt %.

[0262] ITEM 22. The panel according to any one of the preceding items 1 to 21, wherein the mineral-based layer further comprises at least one additive, such as defoaming agent, dispersing agent, anti-corrosion agent, water resistance additive of combinations thereof, in an amount of 0 to 20 wt %, such as 2-15 wt %.

[0263] ITEM 23. The panel according to any one of the preceding items 1 to 22, wherein the panel comprises a mechanical locking system 50a, 50b at respective opposite first 11 and second 12 edges, such as long edges, for assembling a first panel 10 in an assembled position with an adjacent second panel 20 by means of a folding displacement F and/or a vertical displacement of the adjacent panels 10, 20; wherein immediately juxtaposed upper edge portions 111, 121 of the first edge 11 of the first panel 10 and the second edge 22 of the second panel 20 in the assembled position form a vertical plane VP; the first edge 11 comprising a locking strip 116 projecting beyond the vertical plane VP and a locking element 114 projecting from the locking strip 116; the second edge 12 comprising a downwards open locking groove 123 configured to receive the locking element by means of said displacement F for horizontal locking of the adjacent panels, wherein a first pair of horizontal locking surfaces comprises a first locking surface 115 provided by the locking element 114 and a second locking surface 125 provided by the locking groove 123.

[0264] ITEM 24. The mineral-based panel according to item 23, wherein the locking system 50a, 50b is configured such that there is provided play Da, such as a minimum play, between the first locking surface 115 or at least a portion of the first locking surface 115 and the second locking surface 125 or at least a portion of the second locking surface 125 during assembling of the first and second panel 10, 20 by means of said displacement F.

[0265] ITEM 25. The mineral-based panel according to item 23 or 24, wherein the locking system 50a, 50b is configured such that there is provided play Dt, such as a minimum play, between the first locking surface 115, such as at least a portion of the first locking surface 115 and the second locking surfaces 125, such as at least a portion of the second locking surfaces 125, in locking position.

[0266] ITEM 26. The mineral-based panel according to any one of the preceding items 23 to 25, wherein one of the first or second edge 11, 12 comprises a locking tongue 122, 118 and the other of the first or second edge comprises a tongue groove 113, 128; wherein the locking system 50a, 50b is configured such that the locking tongue is received in the tongue groove of the second edge by means of a folding displacement F and/or a vertical displacement, such as a linear vertical translation, of the adjacent second panel 20, for vertical locking of first edge and the second edge.

[0267] ITEM 27. The mineral-based panel according to any one of the preceding items 23 to 26, wherein during said assembling, said upper edge portions 111, 121 are simultaneously in contact in a first contact point P1 and/or an upper wall portion 127 of the tongue groove 123 and an upper portion 126 of the locking tongue 122 are simultaneously in contact in a second contact point P2.

[0268] ITEM 28. The mineral-based panel according to any one of the preceding items 23 to 27, wherein a locking angle LA is formed between the first locking surface 115 and a rear surface 16 of the panel 10, said locking angle LA preferably measured in a clockwise direction from the plane of the first locking surface 115, the locking angle LA being in the range of 40 to 60 degrees, preferably 45 to 55 degrees, more preferably 48 to 52 degrees, such as 50 degrees.

[0269] ITEM 29. The mineral-based panel according to any one of the preceding items 23 to 28, wherein the second locking surface 125 is configured to extend essentially parallel the first locking surface 115 in assembled position of the panels.

[0270] ITEM 30. The mineral-based panel according to any one of the preceding items 23 to 29, wherein assembled position of the first and second panels, there is provided a play Dt, such as a minimum play, between the first locking surface and the second locking surface, preferably the play Dt in in the range of 0 to 0.1 mm, for example measured along a horizontal plane H.

[0271] ITEM 31. The mineral-based panel according to any one of the preceding items 23 to 30, wherein Da is in the range of 0-0.1 mm, for example measured transverse the first locking surface 115.

[0272] ITEM 32. The mineral-based panel according to any one of the preceding items 23 to 31, wherein said play Dt is provided along a substantial portion of the locking surfaces 115, 125.

[0273] ITEM 33. The mineral-based panel according to any one of the preceding items 23 to 32, wherein the locking angle LA is adapted to allow said folding displacement F without abutment of the first locking surface 115 and the second locking surface 125.

[0274] ITEM 34. The mineral-based panel according to any one of the preceding items 23 to 33, wherein the locking angle LA is adapted to allow assembling by means of said folding displacement F without flexing or compression of the locking strip 116.

[0275] ITEM 35. The mineral-based panel according to any one of the preceding items 23 to 34, wherein the locking angle LA is adapted to allow assembling by means of said folding displacement without flexing or compression of the locking element 114.

[0276] ITEM 36. The mineral-based panel according to any one of the preceding items 23 to 35, wherein the locking angle LA is configured such that it is sufficiently low to allow assembling by means of a folding displacement F without overlapping of the second pair of horizontal locking surfaces 125, 115 while the first pair of horizontal locking surfaces 111, 121 are simultaneously in contact.

[0277] ITEM 37. The mineral-based panel according to any one of the preceding items 23 to 36, further comprising a lower arrangement 6 comprising one or more layers, and an upper arrangement 5 comprising one or more layers.

[0278] ITEM 38. The mineral-based panel according to any one of the preceding items 23 to 37, wherein the locking strip 116 is formed in one of a mineral-based layer of the panel or in the core 3 of the panel.

[0279] ITEM 39. The mineral-based panel according to any one of the preceding items 23 to 38, wherein the locking element 114 is formed in a mineral based layer of the panel or in the core 3 of the panel.

[0280] ITEM 40. The mineral-based panel according to any one of the preceding items 23 to 39, wherein the locking element 114 is formed as an integral part of the locking strip 116.

[0281] ITEM 41. The mineral-based panel according to any one of the preceding items 23 to 40, wherein a point P on the second locking surface 125 is displaced along a projected or predetermined trajectory Tp from a first space position P0 to a second space position P0′ in response to a folding displacement F of the second panel 20 to said assembled position, such as folding of the second panel 20 about the second edge 12, wherein said predetermined trajectory Tp is disposed on one side, preferably entirely on one side, of a datum plane Dm of the first locking surface 115 during the folding displacement F.

[0282] ITEM 42. The mineral-based panel according to the preceding item 41, wherein at least one of a first contact point P1 and a second contact point P2 and a third contact point P3 are in contact.

[0283] ITEM 43. The mineral-based panel according to the preceding item 42, wherein said predetermined trajectory Tp forms an arc or a circle having contact point P1 as pivot point.

[0284] ITEM 44. The mineral-based panel according to any one of the preceding items 42 or 43, wherein the first contact point P1 is between at least a portion of respective upper edge portions 111, 121 of the first and second panel 10, 20, and wherein the second contact point P2 is between a first pair of vertical locking surfaces.

[0285] ITEM 45. The mineral-based panel according to any one of the preceding items 1 to 44, wherein one or more of the core and the mineral-based layer comprises non-hydraulic cement, preferably magnesium oxide, and optionally magnesium chloride, such as MgCl.sub.2 and/or magnesium sulphate, such as MgSO.sub.4.

[0286] ITEM 46. A set of mineral-based panels according to any one of the preceding items 1 to 45.

[0287] ITEM 47. A method of producing a mineral-based layer, comprising [0288] mixing water, magnesium oxide, magnesium chloride or magnesium sulphate with a filler component to form a slurry; [0289] adding a polymer compound to said slurry; [0290] drying the slurry to form a layer.

[0291] ITEM 48. The method according to item 47, wherein in the filler component comprises Perlite, Sand, Talc, Fly ash, Calcium Carbonate or combinations thereof.

[0292] ITEM 49. The method according to any one of the preceding items 47 or 48, further comprising a step of adding a de-foaming agent, a dispersing agent, an anti-corrosion agent, a water resistance additive.

[0293] ITEM 50. The method according to any one of the preceding items 47 to 49, wherein the polymer compound is present in the amount 1 to 15 wt %, more preferably 5 to 10 wt % of the mineral-based layer.

[0294] ITEM 51. The method according to any one of the preceding items 47 to 50, wherein the polymer compound comprises Acrylic, Styrene-Acrylic, Vinyl-acetate, Vinyl-Acetate-vinylchloride Styrene-Butadiene, vinylidene chloride or combinations thereof.

[0295] ITEM 52. The method according to any one of the preceding items 47 to 51, wherein the polymer compound is added in the form of a powder or a dispersion.

[0296] ITEM 53. The method according to any one of the preceding items 47 to 52, wherein the polymer compound is added in the form of a dispersion, wherein the pH-value of the polymer dispersion is pH 7 or more.

[0297] ITEM 54. The method according to any one of the preceding items 47 to 53, further comprising the step of adding reinforcement fibres comprising reinforcement fibres according to any one of items 2 to 14.

[0298] ITEM 55. Use of a polymer compound 60, such as a polymer compound according to any one of items 16 to 22, in a mineral-based layer 3, 5, 6 of a building panel 10, such as a floor panel.

[0299] ITEM 56. Use of reinforcement fibres 50, such as according to any one of items 2 to 15, in a mineral-based layer 3, 5, 6 of a building panel 10, such as a floor panel.