Floor material

Abstract

To prevent formation of gaps on an upper surface of a floor material.SOLUTION: There is provided a floor material 10 comprising a base layer 30 and a cushion layer 40 disposed beneath the base layer 30. The base layer 30 consists of a lamination body comprising an upper layer 31, a middle layer 32, and a lower layer 33 formed by a hollow structure 70. The upper layer 31 is larger than the middle layer 32 and the lower layer 33, and the middle layer 32 is disposed offset to form a male tongue portion 51 and a female tongue portion 52 in the base layer 30.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a flooring material to be installed in a building. [Background technology]

[0002] Flooring materials with male and female tongue portions have been known for some time. For example, Patent Document 1 describes a building panel as a flooring material (Utility Model Registration Claims, Figures 1 to 3). This flooring material has a honeycomb structure board laminated on the back side of a wood board, and a hard synthetic resin foam board laminated on the back side of the honeycomb structure board. One side end of the honeycomb structure board protrudes outward to form a male tongue portion, and the other side end of the honeycomb structure board retracts inward to form a female tongue portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 5-69230 Summary of the Invention [Problem to be solved by the invention]

[0004] The flooring material described in Patent Document 1 is made by laminating wood boards, honeycomb structure boards, and hard synthetic resin foam boards, and when the male and female tongue portions of these flooring materials are fitted together and assembled, adjacent flooring materials can be assembled without any gaps.

[0005] However, if adjacent flooring materials are assembled without any gaps, if there are manufacturing or assembly errors in the honeycomb structure boards or hard synthetic resin foam boards, gaps will appear between the wooden boards that form the top surfaces of the flooring materials, and dirt may accumulate in these gaps.

[0006] Therefore, an object of the present invention is to provide a flooring material that is less likely to form gaps on its upper surface. [Means for solving the problem]

[0007] The flooring material for solving the above problem is a flooring material comprising a base layer and a cushion layer arranged below the base layer, wherein the base layer is a laminate of an upper layer, a middle layer and a lower layer formed by a hollow structure, the upper layer being larger than the middle layer and the lower layer, and the middle layer being arranged offset to form a male tongue portion and a female tongue portion in the base layer.

[0008] Furthermore, the upper layer, the middle layer, and the lower layer are all rectangular in plan view, and the length of the sides of the middle layer and the lower layer that are parallel to the length of the side of the upper layer is 1 to 3 mm shorter than the length of the side of the upper layer, the engagement length of the male tongue portion with the lower layer is 4 mm to 15 mm, and the protruding length of the male tongue portion is at least twice the length obtained by subtracting the length of the side of the lower layer from the length of the side of the upper layer.

[0009] The protruding length of the male tongue portion and the thickness of the lower layer form a right triangle with the protruding length of the male tongue portion as the base and the thickness of the lower layer as the height, and the angle θ formed by the base and hypotenuse is 65 degrees or less.

[0010] The middle layer is a hollow structure including a core layer and skin layers disposed on both sides of the core layer in the thickness direction, and the end face of the male tongue portion is formed by the skin layers. The upper layer, the middle layer, and the lower layer are fixed together with double-sided tape, and the double-sided tape is positioned in contact with the inner edges of the male tongue portion and the female tongue portion. [Effects of the Invention]

[0011] According to the present invention, gaps can be made less likely to form on the upper surface of the flooring material. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. [Figure 2] Plan view of flooring. [Figure 3] Figure 3(a) is a side view of the flooring material as seen from below in Figure 2. Figure 3(b) is an enlarged view of both the left and right ends of Figure 3(a). [Figure 4] Figure 4(a) is a cross-sectional perspective view of the hollow structure, Figure 4(b) is a cross-sectional schematic view of the α-α line of Figure 4(a), and Figure 4(c) is a cross-sectional schematic view of the β-β line of the same. [Figure 5] Figure 5(a) is a partial perspective view of the sheet material that constitutes the core layer, Figure 5(b) is a partial perspective view showing the state of the sheet material in the middle of being folded, and Figure 5(c) is a partial perspective view showing the state of the sheet material after being folded. [Figure 6] A floor plan showing four flooring materials arranged in a square shape. [Figure 7] FIG. 7 is a partial cross-sectional view of the arrow portion in FIG. 6. [Figure 8] Figure 8(a) is a side view of a modified example of flooring, Figure 8(b) is an explanatory diagram explaining the relationship between the protruding length of the middle layer and the thickness of the lower layer, and Figure 8(c) is a side view of the modified example of flooring in an inclined state. [Figure 9] FIG. 9(a) is an explanatory diagram of the male tongue portion of the flooring material of this embodiment, and FIGS. 9(b), 9(c), 9(d) and 9(e) are explanatory diagrams of male tongue portions of modified examples. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described below with reference to FIGS. (Overall configuration of flooring material 10) Fig. 1 shows a perspective view of flooring material 10, Fig. 2 shows a plan view of flooring material 10, and Fig. 3 shows a side view of flooring material 10. Flooring material 10 is primarily used by being installed on the concrete floor of buildings, specifically gymnasiums and other indoor sports facilities. It can also be installed and used by layering it on top of an existing floor.

[0014] As shown in Figures 1 and 2, flooring material 10 is approximately square in plan view. As shown in Figures 1 and 3, flooring material 10 is configured by laminating, from top to bottom, a surface layer 20, a base layer 30, and a cushion layer 40. A portion of base layer 30 is positioned offset in a direction perpendicular to the stacking direction (the up-and-down direction in Figure 3), thereby forming male tongue portions 51 and female tongue portions 52 on the side surfaces of flooring material 10 and on the ends of base layer 30. Note that in Figures 1 and 2, the sizes of male tongue portions 51 and female tongue portions 52 relative to flooring material 10 are exaggerated.

[0015] As shown in Figures 3(a) and 3(b), the base layer 30 is a laminate consisting of three layers: an upper layer 31, a middle layer 32, and a lower layer 33. The upper layer 31, the middle layer 32, and the lower layer 33 are fixed together with double-sided tape 34 to prevent relative movement. As shown by the dots in Figure 2, the double-sided tape 34 that fixes the upper layer 31 and the middle layer 32, and the middle layer 32 and the lower layer 33, is positioned in a rectangular frame shape in contact with the inner edges of the male tongue portion 51 and the female tongue portion 52. The surface layer 20 and the upper layer 31, and the lower layer 33 and the cushion layer 40 are fixed together with an adhesive (not shown) to prevent relative movement, forming a single flooring material 10 as a whole. In addition, an anti-slip sheet 41 is partially attached to the underside of the cushion layer 40 to prevent slippage between the flooring material 10 and the installation surface.

[0016] The surface layer 20 is a plate- or sheet-like layer that covers the upper layer 31 of the base layer 30 for purposes such as improving the appearance of the upper surface of the flooring 10, providing elasticity, or displaying functionality (e.g., displaying the floor surface of an indoor sports facility). The surface layer 20 is not particularly limited, and can be made of wood flooring, synthetic resin sheets, or composite materials commonly used as surface materials for indoor sports facilities. Examples of wood flooring include wood-based materials, specifically solid wood, plywood, substrates made of solidified wood fibers, or composites of these. Examples of synthetic resins used for sheets include polyvinyl chloride, urethane resin, and epoxy resin. The surface layer 20 may be formed by coating the upper surface of the base layer 30 with a synthetic resin material. In this case, the surface layer 20 is formed on the base layer 30 by coating, eliminating the need for adhesive between the two layers.

[0017] The upper layer 31, middle layer 32, and lower layer 33 are each composed of a hollow structure 70. The base layer 30, consisting of the upper layer 31, middle layer 32, and lower layer 33, is the basic structure of the flooring material 10. Of the upper layer 31, middle layer 32, and lower layer 33, which are composed of hollow structures 70, the compressive strength of the upper layer 31 is preferably greater than the compressive strength of the middle layer 32 and lower layer 33. The hollow structures 70 that compose the upper layer 31, middle layer 32, and lower layer 33 will be described in more detail below.

[0018] 4(a) shows a cross-sectional perspective view of the hollow structure 70. As shown in the figure, the hollow structure 70 has a hollow plate shape as a whole, with a plurality of columnar cells S arranged side by side inside. Fig. 4(b) shows a cross-sectional view of Fig. 4(a) taken along line α-α, and Fig. 4(c) shows a cross-sectional view of Fig. 4(a) taken along line β-β. As shown in Figs. 4(b) and 4(c), the hollow structure 70 is composed of a core layer 71 having a plurality of columnar cells S arranged side by side therein, and sheet-like skin layers 72 and 73 bonded to both the upper and lower surfaces of the core layer 71. The core layer 71 is formed by folding a single sheet material made of thermoplastic resin molded into a predetermined shape. The core layer 71 is composed of an upper wall portion 74, a lower wall portion 75, and a side wall portion 76 that stands between the upper wall portion 74 and the lower wall portion 75 and divides the cells S into a hexagonal columnar shape.

[0019] As shown in FIGS. 4(b) and 4(c), the cells S defined within the core layer 71 include a first cell S1 and a second cell S2, each having a different structure. As shown in FIG. 4(b), the first cell S1 has a two-layer upper wall portion 74 on top of its side wall portion 76. The layers of this two-layer upper wall portion 74 are bonded to each other. The first cell S1 also has a single-layer lower wall portion 75 on the bottom of its side wall portion 76. On the other hand, as shown in FIG. 4(c), the second cell S2 has a single-layer upper wall portion 74 on top of its side wall portion 76. The second cell S2 also has a two-layer lower wall portion 75 on the bottom of its side wall portion 76. The layers of this two-layer lower wall portion 75 are bonded to each other. As shown in FIGS. 4(b) and 4(c), adjacent first cells S1 and adjacent second cells S2 are defined by two-layer side wall portions 76, respectively. The two-layered sidewall portions 76 have portions that are not heat-welded to each other in the center in the thickness direction of the core layer 71. Therefore, the internal space of each cell S of the core layer 71 communicates with the internal spaces of the other cells S through the two-layered sidewall portions 76.

[0020] As shown in Fig. 4(a), the first cells S1 are arranged in rows along the X direction. Similarly, the second cells S2 are arranged in rows along the X direction. The rows of the first cells S1 and the rows of the second cells S2 are alternately arranged in the Y direction, which is perpendicular to the X direction. The first cells S1 and the second cells S2 form a honeycomb structure in the core layer 71 as a whole.

[0021] As shown in Figures 4(a) to 4(c), a skin layer 72, which is a sheet material made of thermoplastic resin, is bonded to the upper surface of the core layer 71 configured as described above. In addition, a skin layer 73, which is a sheet material made of thermoplastic resin, is bonded to the lower surface of the core layer 71. The core layer 71 and the skin layers 72 and 73 form a hollow plate-like hollow structure 70. An example of a hollow structure 70 configured in this manner is the Texel (registered trademark) series, a product of Gifu Plastic Industry Co., Ltd.

[0022] A method for manufacturing the hollow structural body 70 will now be described. As shown in FIG. 5(a), the first sheet material 100 is formed by molding a single thermoplastic resin sheet into a predetermined shape. The first sheet material 100 has band-shaped flat regions 110 and bulging regions 120 alternately arranged in the longitudinal direction (X direction) of the first sheet material 100. In the bulging region 120, a first bulging portion 121 having a downward groove-like cross section and consisting of an upper surface and a pair of side surfaces is formed over the entire extension direction (Y direction) of the bulging region 120. Note that the angle between the upper surface and the side surface of the first bulging portion 121 is preferably 90 degrees, so that the cross section of the first bulging portion 121 has a downward U-shape. The width of the first bulging portion 121 (the length in the short direction of the upper surface) is set to be equal to the width of the flat region 110 and to be twice the bulging height of the first bulging portion 121 (the length in the short direction of the side surfaces).

[0023] In addition, in the bulging region 120, a plurality of second bulging portions 122, each of which has a cross-sectional shape that is a trapezoid obtained by bisecting a regular hexagon along its longest diagonal, are formed so as to be perpendicular to the first bulging portions 121. The bulging height of the second bulging portions 122 is set to be equal to the bulging height of the first bulging portions 121. The interval between adjacent second bulging portions 122 is equal to the width of the upper surface of the second bulging portions 122.

[0024] The first bulging portion 121 and the second bulging portion 122 are formed by partially bulging the sheet upwards using the plasticity of the sheet. The first sheet material 100 can be formed from a single sheet by a well-known forming method such as vacuum forming or compression forming.

[0025] As shown in FIGS. 5(a) and 5(b), the core layer 71 is formed by folding the first sheet material 100 along the boundary lines P and Q. Specifically, the first sheet material 100 is valley-folded at the boundary line P between the flat region 110 and the bulging region 120, and mountain-folded at the boundary line Q between the top surface and side surface of the first bulging portion 121, thereby compressing it in the X direction. Then, as shown in FIGS. 5(b) and 5(c), the top surface and side surface of the first bulging portion 121 are folded over, and the end surface of the second bulging portion 122 and the flat region 110 are folded over. As a result, one rectangular columnar partition 130 extending in the Y direction is formed for each bulging region 120. Such partitions 130 are continuously formed in the X direction, thereby forming the hollow plate-like core layer 71.

[0026] When the first sheet material 100 is compressed as described above, the upper wall portion 74 of the core layer 71 is formed by the upper surface and side surface of the first bulge portion 121, and the lower wall portion 75 of the core layer 71 is formed by the end surface of the second bulge portion 122 and the flat region 110. As shown in FIG. 5(c), the portion of the upper wall portion 74 where the upper surface and side surface of the first bulge portion 121 are folded over to form a two-layer structure is the overlapping portion 131. In addition, the portion of the lower wall portion 75 where the end surface of the second bulge portion 122 and the flat region 110 are folded over to form a two-layer structure is also the overlapping portion 131.

[0027] Furthermore, the hexagonal columnar region formed by folding the second bulging portion 122 becomes the second cell S2, and the hexagonal columnar region formed between a pair of adjacent partitions 130 becomes the first cell S1. In this embodiment, the upper and side surfaces of the second bulging portion 122 form the side wall portion 76 of the second cell S2, and the side surfaces of the second bulging portion 122 and the flat portions located between the second bulging portions 122 in the bulging region 120 form the side wall portion 76 of the first cell S1. The contact areas between the upper surfaces of the second bulging portions 122 and the contact areas between the flat portions in the bulging region 120 form the side wall portion 76 having a two-layer structure. Note that, when performing this folding process, it is preferable to heat-treat the first sheet material 100 so that it is softened.

[0028] Second sheet materials made of thermoplastic resin are bonded by heat welding to the upper and lower surfaces of the core layer 71 obtained in this manner. The second sheet material bonded to the upper surface of the core layer 71 becomes the skin layer 72, and the second sheet material bonded to the lower surface of the core layer 71 becomes the skin layer 73.

[0029] When the second sheet material (skin layers 72, 73) is heat-sealed to the core layer 71, the two-layered upper wall portions 74 (overlapped portions 131) of the first cell S1 are heat-sealed to each other. Similarly, the two-layered lower wall portions 75 (overlapped portions 131) of the second cell S2 are heat-sealed to each other. Meanwhile, the two-layered side wall portions 76 of the first cell S1 and the second cell S2 are less susceptible to heat transfer than the upper wall portions 74 and the lower wall portions 75. Therefore, there are portions of the two-layered side wall portions 76 that are not heat-sealed to each other. As a result, the internal space of each cell S is not completely closed, and the internal spaces of each cell S are in communication with each other via the two-layered side wall portions 76 that are not heat-sealed to each other.

[0030] The long hollow structure 70 thus produced can be cut to a predetermined size and used as the upper layer 31, the middle layer 32, and the lower layer 33. The cushion layer 40 is a layer that forms the underside of the flooring 10. The cushion layer 40 is a layer that is installed to impart elasticity to the flooring 10 that is placed on a base, and is made of a foam. Resin foam can be used as this foam, with polyurethane foam being preferred. From a cost standpoint, chip urethane foam, which is a recycled product made by crushing and remolding polyurethane foam scraps, is particularly preferred.

[0031] (Regarding the length of the sides, thickness, etc. of each layer that constitutes the flooring material 10) In the flooring material 10, the surface layer 20 and the upper layer 31 have the same shape in a planar view, which in this embodiment is a square of 800 mm x 800 mm in a planar view. The middle layer 32, the lower layer 33, and the cushion layer 40 also have the same shape in a planar view, which in this embodiment is a square of 798 mm x 798 mm in a planar view. Therefore, in the base material layer 30, the upper layer 31 has a side length that is 2 mm longer in a planar view than the middle layer 32 and the lower layer 33. The difference in the side length between the upper layer 31 and the middle layer 32 and the lower layer 33 can be in the range of 1 mm to 5 mm, and preferably in the range of 1 mm to 3 mm.

[0032] The thickness of the surface layer 20 (the length in the vertical direction in FIG. 3; the same applies to the thickness of each layer below) is not particularly specified and may be determined appropriately depending on the intended use, the materials used, etc. The thickness of each hollow structure 70 constituting the upper layer 31, middle layer 32, and lower layer 33 is 5 mm, and each thickness can be in the range of 3 mm to 30 mm, preferably 5 to 20 mm. The thickness of the cushion layer 40 is not particularly specified, but is preferably 4 mm or more to provide cushioning properties. Furthermore, the density of the cushion layer 40 (mass (g) per cubic centimeter) is preferably 0.08 or more. This is because if the density of the cushion layer 40 is less than 0.08, the floor will easily wear down. Furthermore, to ensure elasticity as a floor material 10 for gymnasiums, etc., the density of the cushion layer 40 is preferably 0.1 or more, more preferably 0.15 or more.

[0033] (Regarding the arrangement of the layers constituting the flooring material 10 (positional relationship in plan view of FIG. 2)) The surface layer 20 and the upper layer 31 are squares with sides of the same length in plan view, and are arranged with their four sides aligned.

[0034] As shown in Fig. 2, the middle layer 32 and the lower layer 33 are arranged so as to be offset in a direction perpendicular to the thickness direction with respect to the upper layer 31. For ease of explanation, of the four sides of the upper layer 31, the middle layer 32, and the lower layer 33, the sides located on the lower side, upper side, left side, and right side in Fig. 2 will be referred to as the front side, rear side, left side, and right side, respectively. The front side, rear side, left side, and right side are designated by adding the symbols a, b, c, and d to the component number of each layer.

[0035] In a plan view, the front edge 32a and left edge 32c of the middle layer 32 are positioned so as to protrude outward (to the downward and left in FIG. 2) by 10 mm from the front edge 31a and left edge 31c of the upper layer 31, respectively. Specifically, the front edge 32a of the middle layer 32 protrudes outward by 10 mm from the front edge 31a of the upper layer 31 in the downward direction in FIG. 2, which is perpendicular to the front edge 31a, and both edges are parallel. In addition, the left edge 32c of the middle layer 32 protrudes outward by 10 mm from the left edge 31c of the upper layer 31 in the left direction in FIG. 2, which is perpendicular to the left edge 31c, and both edges are parallel.

[0036] Here, both the upper layer 31 and the middle layer 32 are square in plan view, but the upper layer 31 has a side length of 800 mm, while the middle layer 32 has a side length of 798 mm, a difference of 2 mm between the lengths of the two sides. Therefore, the rear side 32b and the right side 32d of the middle layer 32, which are opposite sides, are positioned inward from the rear side 31b and the right side 31d of the upper layer 31 by a total of 12 mm, which is the protrusion length of 10 mm and the difference in side length of 2 mm.

[0037] Specifically, the rear side 32b of the middle layer 32 is recessed inward from the rear side 31b of the upper layer 31 by 12 mm in a downward direction in Fig. 2, which is perpendicular to the rear side 31b, as shown by the dashed line in Fig. 2. Also, the right side 32d of the middle layer 32 is recessed inward from the right side 31d of the upper layer 31 by 12 mm in a leftward direction in Fig. 2, which is perpendicular to the right side 31d, as shown by the dashed line in Fig. 2, and both sides are parallel.

[0038] The lower layer 33 is arranged such that its front edge 33a and left edge 33c are aligned with the front edge 31a and left edge 31c of the upper layer 31 in a plan view. Both the upper layer 31 and the lower layer 33 are square in a plan view, but the upper layer 31 has a side length of 800 mm while the lower layer 33 has a side length of 798 mm, meaning a difference of 2 mm between the lengths of the two. Therefore, when the front edge 31a and left edge 31c of the upper layer 31 are aligned with the front edge 33a and left edge 33c of the lower layer 33, the opposite sides of the rear edge 33b and right edge 33d of the lower layer 33 are positioned 2 mm inward from the rear edge 31b and right edge 31d of the upper layer 31, respectively.

[0039] Specifically, the rear side 33b of the lower layer 33 is recessed inward by 2 mm from the rear side 31b of the upper layer 31 in a downward direction in Fig. 2 perpendicular to the rear side 31b, as shown by the dashed line in Fig. 2, and both sides are parallel. Also, the right side 33d of the lower layer 33 is recessed inward by 2 mm from the right side 31d of the upper layer 31 in a leftward direction in Fig. 2 perpendicular to the right side 31d, as shown by the dashed line in Fig. 2, and both sides are parallel.

[0040] Furthermore, the positional relationship between the middle layer 32 and the lower layer 33 will be described. The rear side 32b of the middle layer 32, shown by the dashed line in Fig. 2, is recessed 10 mm inward from the rear side 33b of the lower layer 33, shown by the dashed line in Fig. 2, in the downward direction in Fig. 2, which is perpendicular to the rear side 33b, and both sides are parallel. Also, the right side 32d of the middle layer 32, shown by the dashed line in Fig. 2, is recessed 10 mm inward from the right side 33d of the lower layer 33, shown by the dashed line in Fig. 2, in the leftward direction in Fig. 2, which is perpendicular to the right side 33d, and both sides are parallel.

[0041] The cushion layer 40 has a square shape with the same side length as the lower layer 33 in a plan view, and the four sides of the cushion layer 40 and the lower layer 33 are arranged so that their positions are aligned. (Regarding the arrangement of each layer constituting the flooring material 10 (end surface in side view)) As shown in Figure 3(b), at the left end of the flooring material 10, the surface layer 20, upper layer 31, lower layer 33, and cushion layer 40 are aligned with their sides, so that their end faces are flush. In contrast, the end face of the middle layer 32 protrudes 10 mm outward (to the left in the figure) relative to the upper layer 31 and lower layer 33 of the base material layer 30, and this protruding portion of the middle layer 32 forms a male tongue 51. In other words, the male tongue 51 has a protruding length 51a of 10 mm.

[0042] 3(b), at the right end of the flooring material 10, the surface layer 20 and the upper layer 31 are aligned with their sides, so their end faces are flush. The lower layer 33 and the cushion layer 40 are also aligned with their sides, so their end faces are flush. However, the lower layer 33 and the cushion layer 40 are square in plan view, with each side 2 mm shorter than the upper layer 31, so the sides and end faces of the lower layer 33 and the cushion layer 40 are recessed 2 mm inward from the upper layer 31, to the left in the figure.

[0043] Furthermore, as shown in Figure 3(b), at the end on the right side of flooring material 10, the end face of middle layer 32 is recessed 12 mm inward (to the left in the figure) from upper layer 31 and 10 mm from lower layer 33. The recessed space formed between upper layer 31 and lower layer 33 by recessing middle layer 32 forms female tongue portion 52. The end faces of flooring material 10 shown in Figure 3(b) are also the same when flooring material 10 is viewed from the right in Figure 2.

[0044] (Assembling the flooring material 10) FIG. 6 shows a plan view of four flooring materials 10 assembled in a square-shaped configuration. Furthermore, FIG. 7 shows a partial cross-sectional view of FIG. 6. Note that hatching indicating cross sections has been omitted in FIG. 7 for ease of explanation. As shown in FIGS. 6 and 7, when the flooring materials 10 are assembled, the end faces of the surface layer 20 and upper layer 31, which have the longest sides of the flooring materials 10, each measuring 800 mm in plan view, abut the end faces of the surface layer 20 and upper layer 31 of the adjacent flooring materials 10 along the entire length of the side. Meanwhile, the middle layer 32, lower layer 33, and cushion layer 40 have sides that are 798 mm in plan view, which is 2 mm shorter than the side lengths of the surface layer 20 and upper layer 31. Therefore, a 2 mm gap is formed between the end faces of the middle layer 32, lower layer 33, and cushion layer 40 of adjacent flooring materials 10 along the entire length of the side, in a direction perpendicular to the thickness direction. A gap of 2 mm in length is also formed in the same direction between the end faces of the male tongue portion 51 and the female tongue portion 52.

[0045] Furthermore, the male tongue portion 51 of the middle layer 32 of the flooring materials 10 fits into the female tongue portion 52 of the adjacent flooring material 10. Specifically, as shown in Figure 7, the male tongue portion 51 of one flooring material 10 fits into the female tongue portion 52 of the adjacent flooring material 10, and the two are fitted together. The vertical movement of the male tongue portion 51 is restricted by the upper layer 31 and lower layer 33, which are positioned above and below the female tongue portion 52, so even if a load is applied from above to the fitted portion between the male tongue portions 51 and female tongue portions 52 of the flooring materials 10, this portion is less likely to sink.

[0046] The engagement length 51b of the male tongue portion 51 is preferably in the range of 4 mm to 15 mm. If the engagement length 51b is shorter than 4 mm, the length of the mating portion between the male tongue portion 51 and the female tongue portion 52 becomes shorter, resulting in a greater load on the mating portion. Furthermore, if the engagement length 51b is longer than 15 mm, it becomes difficult to insert the male tongue portion 51 into the female tongue portion 52 unless the angle of the flooring material 10 to be assembled to the previously installed flooring material 10 is adjusted, making the assembly process more complicated. The engagement length 51b here refers to the length of the male tongue portion 51 that contacts the upper surface of the lower layer 33 of the adjacent flooring material 10, out of the protruding length 51a of the male tongue portion 51 from the lower layer 33, as shown in FIG. 7. In this embodiment, the tip of the male tongue portion 51 contacts the upper surface of the lower layer 33 of the adjacent flooring material 10, so the engagement allowance 51b is 8 mm, which is obtained by subtracting 2 mm, which is the gap 51c between the lower layers 33 that is formed when the flooring material 10 is assembled, from 10 mm, which is the protrusion length 51a of the male tongue portion 51. The gap 51c between the lower layers 33 can be calculated as the length obtained by subtracting the length of the side of the lower layer 33 (798 mm) from the length of the side of the upper layer 31 (800 mm).

[0047] Furthermore, it is preferable that the protruding length 51a of the male tongue portion 51 is at least twice the gap 51c between the lower layers 33. The gap 51c between the lower layers 33 is the portion where the male tongue portion 51 does not engage with the lower layer 33. Therefore, by making the length of the male tongue portion 51 at least twice the gap 51c between the lower layers 33, the engagement allowance 51b is sufficiently secured, and even if a load is applied to the mating portion between the male tongue portion 51 and the female tongue portion 52, the load on this portion will not be large. In this embodiment, the protruding length 51a of the male tongue portion 51 is 10 mm, and the gap 51c between the lower layers 33 is 2 mm. Therefore, the length 10 mm of the male tongue portion 51 is five times the 2 mm of the gap 51c between the lower layers 33.

[0048] According to the flooring material 10 of the above embodiment, the following effects can be obtained. (1) In the above embodiment, the upper layer 31, the middle layer 32, and the lower layer 33 that make up the base material layer 30 are formed from the hollow structures 70, so the flooring material 10 is lightweight.

[0049] (2) The upper layer 31 that constitutes the base layer 30 is larger than the middle layer 32 and the lower layer 33, and the middle layer 32 is positioned offset, thereby forming male tongue portions 51 and female tongue portions 52 at the ends of the base layer 30. Therefore, when the male tongue portions 51 and female tongue portions 52 of adjacent flooring materials 10 are assembled, no gaps are formed between the top surfaces 20 and upper layers 31 of adjacent flooring materials 10, making it difficult for debris to accumulate.

[0050] (3) The upper layer 31, middle layer 32, and lower layer 33 are all square in plan view, and the sides of the middle layer 32 and lower layer 33 are 2 mm shorter than the side of the upper layer 31. Therefore, even if there are manufacturing errors, assembly errors, etc., gaps are less likely to occur between the top surfaces 20 of adjacent flooring materials 10 and between the upper layers 31.

[0051] (4) The engagement allowance 51b of the male tongue portion 51 is 8 mm. Furthermore, the protruding length 51a of the male tongue portion 51, 10 mm, is five times the 2 mm gap 51c between the lower layers 33. Therefore, the engagement allowance 51b is sufficiently secured, and even if a load is applied to the mating portion between the male tongue portion 51 and the female tongue portion 52, the load on this portion will not be large.

[0052] (5) The upper layer 31, middle layer 32, and lower layer 33 are secured to each other with double-sided tape 34, which is positioned in contact with the inner edges of the male tongue portion 51 and the female tongue portion 52 (FIGS. 3(b) and 7). The thickness of the space that becomes the female tongue portion 52 (the vertical distance between the upper layer 31 and the lower layer 33) is the sum of the thickness of the middle layer 32 and the thickness of the upper and lower double-sided tapes 34. Therefore, the thickness of the female tongue portion 52 is greater than the thickness of the male tongue portion 51, which is the thickness of the middle layer 32, by the thickness of the upper and lower double-sided tapes 34, making it easier to insert the male tongue portion 51 into the female tongue portion 52. The thickness of each double-sided tape 34 is thinner than the thickness of each skin layer 72, 73 of the hollow structure 70. Because gaps will be formed between the layers where the double-sided tape 34 is not positioned, it is preferable that the double-sided tape 34 be thinner. It should be noted that the thickness of the double-sided tape 34 is not shown in FIG. 3(b) and FIG.

[0053] This embodiment can also be modified as follows. The thickness of the hollow structures 70 of the upper layer 31, middle layer 32, and lower layer 33 that make up the base material layer 30 can be changed. The thicknesses of the upper layer 31, middle layer 32, and lower layer 33 may be the same or different. In this case, it is preferable to make the thickness of the middle layer 32, which is more likely to receive a load as the male tongue portion 51, thicker than the upper layer 31 and lower layer 33.

[0054] In Figure 6, the flooring materials 10 are assembled in a square shape, i.e., the vertical and horizontal sides (joints) of the multiple flooring materials 10 are aligned in a straight line, a so-called "imo-joint" shape, but this is not limited to this. The flooring materials 10 may also be assembled in a so-called "uma-joint" shape, where one of the vertical and horizontal sides (joints) is aligned in a straight line and the other side (joint) is shifted by half the length.

[0055] The upper layer 31, the middle layer 32, and the lower layer 33 are fixed to each other with double-sided tape 34, but adhesive may also be used. As shown in FIG. 8(a), the relationship between the protruding length 51a of the male tongue 51 of the middle layer 32 and the thickness of the lower layer 33 may be changed as follows. As shown in FIG. 8(b), the angle θ formed by the base and hypotenuse of a right triangle, with the protruding length 51a of the male tongue 51 as the base length and the thickness t of the lower layer 33 as the height, can be set to 65 degrees or less. As a result, as shown in FIG. 8(c), even if the flooring material 10 is tilted with the male tongue 51 facing downward and the weight of the flooring material 10 is concentrated on the edge of the cushion layer 40, causing the edge of the cushion layer 40 to collapse, the tip of the male tongue 51 is unlikely to come into contact with the ground as long as the angle of the flooring material 10 is less than approximately 70 degrees. This makes it easier to protect the male tongue 51 when handling the flooring material 10.

[0056] In this embodiment, the surface layer 20 is disposed on the base material layer 30, but this surface layer 20 may be omitted. The middle layer 32 forming the male tongue portion 51 is configured as a hollow structure 70 including a core layer 71 and skin layers 72, 73 arranged on both sides of the core layer 71 in the thickness direction. As shown in FIG. 9( a), the end face of the male tongue portion 51 is configured from the core layer 71 and the skin layers 72, 73 arranged on both sides of the core layer 71 in the thickness direction, with the cut surface of this hollow structure 70 exposed. When inserting the male tongue portion 51 into the female tongue portion 52, it is conceivable that the cut skin layers 72, 73 on the end face of the male tongue portion 51 may get caught at the entrance of the female tongue portion 52. For this reason, the end face of the male tongue portion 51 may be configured with the skin layers 72, 73 to make it easier to insert into the female tongue portion 52.

[0057] Specifically, as shown in FIG. 9(b), the end face of the male tongue portion 51 may be tapered in side view. In this case, the tapered portion is formed by joining skin layers 72, 73. Alternatively, as shown in FIG. 9(c), the end face of the male tongue portion 51 may be trapezoidal in side view. In this case, the trapezoidal portion in FIG. 9(c) is formed by joining skin layers 72, 73. Furthermore, as shown in FIG. 9(d), the end face of the male tongue portion 51 may be arc-shaped in side view. In this case, the arc-shaped portion is formed by skin layers 72, 73. Alternatively, as shown in FIG. 9(e), the end face of the male tongue portion 51 may be covered with skin layers 72, 73. Even in this case, the end face of the male tongue portion 51 does not have the skin layers 72, 73 cut off, which reduces the risk of the male tongue portion 51 getting caught during insertion. These shapes can be formed on the hollow structure 70 by hot pressing or the like. Furthermore, when the end face of the male tongue portion 51 is made arc-shaped as shown in Figure 9 (d), the tip position of the engagement margin 51b of the male tongue portion 51 is the position where the arc portion ends and it can come into contact with the lower layer 33.

[0058] The end face of the male tongue portion 51 is sealed by the skin layers 72, 73 by processing the upper skin layer 72 into a curved shape using a heat press or the like, and joining it to the tip of the lower skin layer 73 by welding or the like to seal the end face. The joint portion of the skin layers 72, 73 can then be cut like a chamfer with a blade to form an inclined surface on the underside of the joint portion between the skin layers 72 and 73.

[0059] Furthermore, even if the end surfaces of the male tongue 51 are not covered with the skin layers 72, 73, the skin layers 72, 73 near the end surfaces of the male tongue 51 may be inclined so that the distance between their upper and lower ends decreases as they extend outward. This configuration reduces the tapered tip of the male tongue 51, reducing the chance of the male tongue 51 getting caught during insertion, even if the end surfaces of the male tongue 51 have uncut skin layers 72, 73. The inclination of the skin layers 72, 73 can be achieved by processing the skin layers 72, 73 located at the tip of the male tongue 51 into a straight or curved shape in side view using a heat press or similar. Furthermore, the skin layers 72, 73 located at the tip of the male tongue 51 can be cut with a blade, similar to chamfering, to form a straight or curved shape in side view. For example, the tip of the upper skin layer 72 may be curved using a heat press, and the lower surface of the tip of the lower skin layer 73 may be cut to form a straight slope.

[0060] While each layer constituting the flooring material 10 has a square shape in plan view, this is not limited to this and may have a rectangular shape in plan view. For example, the surface layer 20 and upper layer 31 may have a rectangular shape in plan view of 1600 mm x 800 mm, and the middle layer 32, lower layer 33, and cushion layer 40 may have rectangular shapes in plan view of 1598 mm x 798 mm, which are 2 mm shorter than the upper layer 31. Furthermore, a flooring material 10 that is rectangular in plan view and a flooring material 10 that is square in plan view may be used in combination.

[0061] The number of base layers 30 is not limited to three, and may be four or more. In the case of four layers, at least one of the two central layers may be arranged offset as a middle layer 32 to form the male tongue portion 51 and the female tongue portion 52.

[0062] Although the size of the cushion layer 40 in a plan view is the same as that of the lower layer 33, this is not limitative. For example, the size of the cushion layer 40 in a plan view may be the same as that of the upper layer 31.

[0063] Specific examples will be described below. Preparation of test specimens A flooring material 10 including a surface layer 20, a base layer 30 (upper layer 31, middle layer 32, and lower layer 33), and a cushion layer 40 was produced.

[0064] For the surface layer 20, a synthetic resin sheet (a laminated sheet with a urethane layer on the bottom and a polyvinyl chloride layer on the top, thickness 4.5 mm) manufactured by Company A was used. For the upper layer 31, middle layer 32 and lower layer 33 constituting the base layer 30, Texel (registered trademark) T5-1870 (thickness 5.5 mm, compressive modulus 89.1 MPa) manufactured by Gifu Plastic Industry Co., Ltd. was used as the hollow structure 70.

[0065] For the cushion layer 40, the following samples 1 to 4 were used, which were chip urethane foams, which were recycled products made by crushing and remolding polyurethane foam scraps. They had different densities and thicknesses. Sample 1 had a density of 0.2 g / cm 3 The sample 2 had a density of 0.2 g / cm and a thickness of 7 mm. 3 Sample 3 was a 0.25 g / cm3 sample with a thickness of 6 mm. 3 Sample 4 was a sample with a density of 0.25 g / cm 3 A 6mm thick plate was used.

[0066] The surface layer 20 and upper layer 31 were 800 mm x 800 mm squares in plan view, and the middle layer 32, lower layer 33, and cushion layer 40 were 798 mm x 798 mm squares in plan view. The positions of two adjacent sides of the surface layer 20, upper layer 31, lower layer 33, and cushion layer 40 were aligned, and the middle layer 32 was protruded 10 mm outward from each of the two sides to form male tongue portions 51. In addition, on the two sides opposite the male tongue portion 51, the middle layer 32 was formed with female tongue portions 52 positioned 12 mm inward from the surface layer 20 and upper layer 31, respectively, and 10 mm inward from the lower layer 33 and cushion layer 40, respectively.

[0067] Test floor materials 1 to 4 shown in Table 1 were created by stacking, from top to bottom, the surface layer 20, upper layer 31, middle layer 32, lower layer 33, and cushion layer 40 (any of samples 1 to 4), and bonding each layer together with a urethane adhesive.

[0068] [Table 1]

[0069] Floor resilience test Floor resilience tests were conducted on test floor materials 1 to 4. The floor resilience tests measured the "hardness performance value" and "vibration continuity performance value" specified in JIS A6519 9.4 Floor Resilience Test. The measuring equipment used was a test equipment owned by the Construction Materials Testing Center, a general incorporated association, that is equivalent to the above-mentioned test. The measurement details of the resilience tests are shown in Table 2.

[0070] [Table 2]

[0071] JIS A6519 specifies that each value be measured at four locations. This is because a double-floor structure combining posts, joists, and floor joists is assumed, and the elasticity of the floor varies depending on the location. In this embodiment, since the floor hardness is less likely to vary depending on the location, measurements were taken at the intersection of the diagonal lines of the surface layer 20 (referred to as the "center" in Table 3) for each of test floor materials 1 to 4. In addition, two of the same test floor materials were used, and measurements were taken at the boundary between the surface layers 20 where the male tongue portion 51 and the female tongue portion 52 are fitted, at the center of the length of the side (400 mm from the end of the side of the surface layer 20) (referred to as the "tongue portion" in Tables 3 and 4).

[0072] Table 3 shows the results of the measurement tests of the performance values ​​shown in Table 2, which were conducted on Test Floor Materials 1 to 4.

[0073] [Table 3]

[0074] As a result, all of the test floor materials 1 to 4 satisfied the recommended values ​​specified in the above JIS for (a) the performance value of hardness and (b) the performance value of the duration of vibration. Impact absorption (JIS A6519 Floor hardness test method) The impact absorption value (G value) was measured at one arbitrary location (excluding the tongue portion) and at the tongue portion for each of the above test floor materials 1 to 4. The G values ​​for test floor materials 1 to 4 are shown in Table 4.

[0075] [Table 4]

[0076] The G value was less than 100 for all test floor materials 1 to 4. Next, the technical ideas that can be understood from the above-described embodiment and other examples will be described below together with their effects.

[0077] (a) A flooring material in which the cushion layer is made of chip urethane foam. According to the technical idea described in (a), the cost of the cushion layer can be reduced. [Explanation of symbols]

[0078] 10...Flooring 20…Surface layer 30...Base material layer 31...upper layer 32...middle layer 33…lower layer 34...Double-sided tape 40...Cushion layer 51... Male Sanebu 51a...Protruding length of male tongue 51b...Hooking fee 52...Female sane section 70...Hollow structure 71...Core layer 72...Skin layer 73...Skin layer t...thickness of the lower layer

Claims

1. A flooring material comprising a base layer and a cushion layer disposed under the base layer, The base layer is a laminate of an upper layer, a middle layer and a lower layer formed by a hollow structure, the upper layer being larger than the middle layer and the lower layer, and the middle layer being positioned in an offset manner to form male and female tongue portions in the base layer.

2. The flooring material according to claim 1, wherein the upper layer, the middle layer, and the lower layer are all rectangular in plan view, the length of the sides of the middle layer and the lower layer that are parallel to the length of the side of the upper layer is 1 to 3 mm shorter than the length of the side of the upper layer, the overlapping margin of the male tongue portion with the lower layer is 4 mm to 15 mm, and the protruding length of the male tongue portion is at least twice the length obtained by subtracting the length of the side of the lower layer from the length of the side of the upper layer.

3. The flooring material according to claim 1, wherein the protruding length of the male tongue portion and the thickness of the lower layer are such that the angle θ formed by the base and hypotenuse of a right triangle with the protruding length of the male tongue portion as the base and the thickness of the lower layer as the height is 65 degrees or less.

4. The flooring material described in any one of claims 1 to 3, wherein the middle layer is a hollow structure having a core layer and skin layers arranged on both thickness-wise sides of the core layer, and the end surface of the male tongue portion is formed by the skin layer.

5. The upper layer, the middle layer and the lower layer are fixed together with double-sided tape, and the double-sided tape is positioned in contact with the inner edges of the male tongue portion and the female tongue portion. A flooring material as described in any one of claims 1 to 3.

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