Shock-absorbing flooring material

Abstract

The purpose of the present disclosure is to provide shock-absorbing flooring material (flooring material) that maintains an absorption effect of a soft layer while also having excellent load bearing properties. A flooring material (1) according to the present embodiment comprises a flooring upper material (11), a flooring substrate material (12) provided below the flooring upper material (11), and an intermediate material (13) provided between the flooring upper material (11) and the flooring substrate material (12). The flooring substrate material (12) is formed from a resin material and has a foam structure. The intermediate material (13) is formed from a material that includes a thermoplastic resin and an inorganic filler. In a three-point bend test in accordance with JIS K7074, the strain (ε(σmax)) at which bending strength is a maximum is not less than 0.5%, and the flexural modulus is not less than 1 GPa.

Description

Shock-absorbing flooring

[0001] The present disclosure relates to impact absorbing flooring.

[0002] Falls and fractures account for 10% of the reasons why elderly people require nursing care. Femoral fractures, the risk of which increases with age, require long-term hospitalization and treatment, and are likely to lead to elderly people requiring nursing care, such as becoming bedridden or developing dementia. For this reason, flooring materials have been proposed that reduce the risk of fractures by absorbing the impact on the femur when a pedestrian falls (e.g., Patent Documents 1 and 2). Such flooring materials often have a shock-absorbing function, either by foaming the flooring material itself or by providing a soft member such as a foam resin sheet on the backside of the flooring material.

[0003] Patent No. 3600726 Patent No. 5244927

[0004] However, such flooring materials have the problem that the soft layer is crushed and dents are generated when moving heavy objects with casters, such as electric nursing care beds or food delivery carts. The present disclosure has been made in consideration of such problems, and aims to provide an impact-absorbing flooring material that has excellent load-bearing capacity while retaining the impact absorption effect of the soft layer.

[0005] In order to solve the above-mentioned problems, a flooring material according to one embodiment of the present disclosure comprises a top-floor material, a sub-floor material provided below the top-floor material, and an intermediate material provided between the top-floor material and the sub-floor material, wherein the sub-floor material is formed from a resin material and has a foam structure, and the intermediate material is formed from a material containing a thermoplastic resin and an inorganic filler, and in a three-point bending test according to JIS K7074, the strain (ε (σmax)) at which the bending strength is maximized is 0.5% or more, and the bending modulus is 1 GPa or more.

[0006] According to the present disclosure, it is possible to provide an impact-absorbing flooring material that has excellent load-bearing capacity while still providing the impact-absorbing effect of the soft layer.

[0007] FIG. 1 is a cross-sectional view showing an example configuration of a flooring material according to a first embodiment of the present disclosure. FIG. 2 is a schematic view for explaining a device for measuring the impact absorption of a flooring material according to a first embodiment of the present disclosure. FIG. 3 is a plan view, a cross-sectional view, and an enlarged view showing an example configuration of a flooring material according to a second embodiment of the present disclosure. FIG. 4 is a plan view and a cross-sectional view showing a more detailed configuration of a base panel used in a flooring material according to a second embodiment of the present disclosure, and a cross-sectional view showing the configuration of a flooring material using the base panel. FIG. 5 is a plan view showing another configuration of a base panel used in a flooring material according to a second embodiment of the present disclosure. FIG. 6 is a plan view and a cross-sectional view showing the configuration of a sample used in load-bearing capacity evaluation in Examples 5 to 7 of the present disclosure.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the embodiments described below exemplify devices and methods for embodying the technical ideas of the present disclosure. Furthermore, the technical ideas of the present disclosure can be modified in various ways within the technical scope described in the claims.

[0009] 1. First Embodiment Hereinafter, an impact-absorbing floor material according to a first embodiment of the present disclosure will be described.

[0010] (1.1) Basic Configuration of Impact-Absorbing Floor Material The impact-absorbing floor material (hereinafter referred to as the floor material) 1 according to the present disclosure will be described below with reference to Figure 1. The floor material 1 comprises an upper floor material 11, an underfloor material 12 provided below the upper floor material 11 (the surface to which the floor material 1 is attached), and an intermediate material 13 provided between the upper floor material 11 and the underfloor material 12.

[0011] The overfloor material 11 has surface functions such as improving the scratch resistance and stain resistance of the floor material 1 and adding design features to the floor material 1. The underfloor material 12 has the function of absorbing pressure when a user falls and increasing the cushioning properties of the floor material 1. The intermediate material 13 serves as a support layer, dispersing the load applied from the overfloor material 11 to the underfloor material 12 and improving shock absorption and load resistance.

[0012] The total thickness of the flooring material 1 is preferably more than 7 mm and not more than 25 mm. If the total thickness of the flooring material 1 is more than 7 mm, it is easier to balance shock absorption, walking comfort, and durability. Furthermore, if the total thickness of the flooring material 1 is 25 mm or less, the thickness of the flooring material 1 will not be too large, so the difference in level between the non-installed portion of the flooring material 1 and the non-installed portion will not be too large, and the flooring material 1 will fit well during installation. Below, the top floor material 11, underfloor material 12, and intermediate material 13 will be described in detail.

[0013] <Overfloor material> The overfloor material 11 is a layer that forms the surface of the floor material 1, and is made of a harder material than the underfloor material 12. The thickness of the overfloor material 11 is preferably 5 mm or less. By making the thickness of the overfloor material 11 5 mm or less, the weight of the floor material 1 does not become too heavy, and the burden during construction can be reduced.

[0014] The overfloor material 11 can be made of common materials such as long vinyl chloride sheets or vinyl chloride tiles. The overfloor material 11 and the intermediate material 13 can be laminated together by adhesive tape or bonding using an adhesive. The overfloor material 11 may be laminated to the intermediate material 13 by thermal lamination in a process subsequent to the manufacturing process of the intermediate material 13.

[0015] <Underfloor material> The underfloor material 12 is provided below the overfloor material 11 (opposite the surface of the overfloor material 11). The underfloor material 12 is made of a softer material than the overfloor material 11, and has the function of absorbing impact on the floor material 1 by deforming appropriately in the event of a fall. The underfloor material 12 has a foam structure formed by a method such as chemical foaming, physical foaming, or supercritical foaming. The resin foam structure may be either a closed-cell foam structure or an open-cell foam structure.

[0016] The floor underlayment material 12 having a foam structure is formed from a thermoplastic resin such as polyethylene, polypropylene, polyvinyl chloride, ethylene vinyl acetate copolymer, polystyrene, polyurethane, or other resin.

[0017] The Asker C hardness of the underfloor material 12 is preferably 25 or more and 60 or less. Here, "Asker C" is a measuring instrument for measuring hardness, and is one of the durometers (spring-type hardness testers) specified in SRIS0101 (Japan Rubber Association Standard). In other words, "Asker C hardness" refers to a value measured with the above-mentioned Asker C hardness tester. If the Asker C hardness of the underfloor material 12 is 25 or more and 60 or less, it becomes easier to ensure the impact absorption of the floor material 1 and also makes it less likely that discomfort will occur when walking.

[0018] The thickness of the underfloor material 12 is preferably 4 mm to 15 mm. If the thickness is 4 mm to 15 mm, it becomes easier to ensure shock absorption and load resistance, and discomfort when walking is reduced.

[0019] <Intermediate Material> The intermediate material 13 has appropriate mechanical properties (bending stress-strain characteristics), and is a layer that undergoes minimal deformation during normal use, but deforms appropriately when a large impact such as a fall is applied, dispersing the impact that the human body receives from the floor surface. In other words, the intermediate material 13 has the function of improving the impact absorption and load-bearing capacity of the flooring material 1.

[0020] The intermediate material 13 having such mechanical properties is formed from a material containing a thermoplastic resin and an inorganic filler. A composite of a thermoplastic resin and an inorganic filler is preferably used as the intermediate material 13. The intermediate material 13 can be obtained, for example, by molding a masterbatch, which is a mixture of a resin material and an inorganic filler, into a plate using a T-die extruder. Examples of thermoplastic resins that can be used include polyethylene, polypropylene, and polyvinyl chloride. Examples of inorganic fillers that can be used include calcium carbonate, calcium silicate, mica, talc, and glass fiber, with mica, talc, and glass fiber being more preferred. This is because the flooring material 1 can have higher load-bearing capacity with the same amount of inorganic filler. Furthermore, the inorganic filler preferably has a scaly, plate-like, or fibrous shape. The use of these inorganic fillers can achieve better mechanical properties (bending stress-strain characteristics) and further improve load-bearing capacity. The intermediate material 13 has a foam structure, such as closed or open cells, formed by methods such as chemical foaming, physical foaming, or supercritical foaming, in order to improve the impact absorption effect of the flooring material 1. The intermediate material 13 having a foam structure can also reduce the weight of the floor material 1, improving workability during installation of the floor material 1.

[0021] The thickness of the intermediate material 13 is preferably 2 mm or more and 8 mm or less. By setting the thickness to 2 mm or more and 8 mm or less, the necessary shock absorption and load resistance can be obtained, and the intermediate material 13 is not too heavy, so that problems with workability during installation are unlikely to occur.

[0022] The intermediate material 13 has appropriate mechanical properties (bending stress-strain properties) such that the strain (ε(σmax)) at which bending strength is maximized in a three-point bending test according to JIS K7074 is 0.5% or more, preferably 0.5% or more, and the bending modulus is 1 GPa or more. If the above-mentioned strain ε(σmax) of the intermediate material 13 is less than 0.5% or the bending modulus is less than 1 GPa, the intermediate material 13 is prone to damage such as cracks and breaks when a large load is applied to the flooring material 1, and the impact absorption properties of the damaged areas may be reduced. In addition, the flooring material 1 may have appearance abnormalities such as unevenness.

[0023] Furthermore, the distortion (ε(σmax)) of the intermediate material 13 described above is preferably 3% or more, and more preferably 6% or more. When the distortion (ε(σmax)) of the intermediate material 13 described above is 3% or more, the load-bearing capacity of the floor material 1 against a large load (e.g., 100 kg) is improved, and when it is 6% or more, the load-bearing capacity of the floor material 1 against a large load (e.g., 100 kg) is further improved. Furthermore, the flexural modulus of the intermediate material 13 is preferably 15 GPa or less. When the flexural modulus of the intermediate material 13 is 15 GPa or less, load distribution is effectively achieved when an impact is applied to the floor material 1 when a large load is applied to the floor material 1, and the cushioning effect of the floor material 1 is further improved.

[0024] <Method for evaluating the impact absorption of flooring material> A method for evaluating the impact absorption of flooring material 1 will be described with reference to Fig. 2. The impact absorption of the flooring material is evaluated by the "impact load F", which is a simulated measurement of the impact load applied to the femur when falling on the flooring material. The impact load F is measured by the method described in JP 2020-76764 A.

[0025] The impact load is measured using an impact load measuring device 200 shown in Fig. 2. The impact load measuring device 200 includes a measurement table 210, an impact applying body 220, a buffer material 230, and a load measuring means 240. Note that the flooring material 1 shown in Fig. 2 is the object of impact load measurement using the impact load measuring device 200, and is not a part of the impact load measuring device 200.

[0026] The impactor 220 has a weight 221 and a hitting portion 222. The weight 221 has a mass based on the pressure distribution applied to the trochanter of the femur due to the simulated fall. The hitting portion 222 is formed in a shape that simulates the trochanter of the femur. The buffer material 230 is formed from a material that simulates human soft tissue. The load measuring means 240 is a device, and may be a load cell, for example, that measures the force applied to the buffer material 230 when the impactor 220 is dropped onto it.

[0027] When measuring the impact absorption of a flooring material, as shown in FIG. 2 , the flooring material 1 to be measured is placed between the buffer material 230 and the load measuring means 240. The load measuring means 240 measures the change over time in the force applied to the buffer material 230 when the impactor 220 is dropped onto the buffer material 230 from a predetermined height corresponding to the height of the simulated fall, with the flooring material 1 placed between the load measuring means (load cell) 240 placed on the measurement table 210 and the buffer material 230. At this time, the load measuring means 240 measures the change over time in the force applied to the buffer material 230 by the impactor 220 from the time the impactor 220 contacts the buffer material 230 until it stops, and the maximum value of the measured load is defined as the impact load F. At this time, the drop height of the impactor 220 is set so that the impact load (reference impact load Fs) when an impact is applied only to the buffer material 230 is 5600 N, simulating the impact on the femur during an actual fall.

[0028] Under the above conditions, the impact load F on the flooring material 1 is preferably 5000 N or less, and more preferably 3440 N or less. If the impact load exceeds 5000 N, the risk of femur fracture in elderly people becomes significant.

[0029] <Effects of the Flooring Material According to the Present Disclosure> The flooring material according to the present disclosure described above has the following effects: (1) The flooring material according to the present disclosure comprises a top-floor material, an under-floor material provided below the top-floor material, and an intermediate material provided between the top-floor material and the under-floor material, the under-floor material being formed from a resin material and having a foam structure, and the intermediate material being formed from a material containing a thermoplastic resin and an inorganic filler, and in a three-point bending test according to JIS K7074, the strain (ε (σmax)) at which the bending strength is maximized is 0.5% or more, and the bending modulus is 1 GPa or more. This allows the flooring material to have excellent load-bearing capacity while maintaining the absorption effect of the soft layer.

[0030] (2) In the flooring material according to the present disclosure, the inorganic filler contained in the intermediate material may have a flaky, plate-like, or fibrous shape, which improves the mechanical properties (bending stress-strain characteristics) of the flooring material and improves its load-bearing capacity.

[0031] (3) In the flooring material according to the present disclosure, the intermediate material may have the above-described strain ε (σmax) of 3% or more, which further improves both the impact absorption and load-bearing capacity of the flooring material.

[0032] 2. Second Embodiment The following describes a shock-absorbing flooring material according to a second embodiment of the present disclosure. The shock-absorbing flooring material according to the second embodiment is composed of multiple base panels and a floor covering that covers the base panels. The shock-absorbing flooring material according to the second embodiment will be described in detail below with reference to Figure 3.

[0033] (2.1) Basic Structure of the Impact-Absorbing Flooring Material The impact-absorbing flooring material (hereinafter referred to as the "flooring material") 2 according to this embodiment will be described below with reference to Figures 3(A) to 3(C) and Figures 4(A) to 4(C). Figure 3(A) is a plan view showing the structure of the flooring material 2, with the top floor material 11 of the flooring material 2 omitted. Figure 3(B) is a cross-sectional view showing the cross-sectional structure of the flooring material 2, taken along the line A-A in Figure 3(A). Figure 3(C) is an enlarged view showing one intermediate material 13 and its surrounding area of ​​the flooring material 2 shown in Figure 3(A). Figure 4(A) is a plan view showing the structure of the base panel 14 constituting the flooring material 2, Figure 4(B) is a cross-sectional view showing the cross-sectional structure of the base panel 14 constituting the flooring material 2, and Figure 4(C) is a cross-sectional view showing the cross-sectional structure of the flooring material 2. The base panels 14 shown in Figure 4 represent, as an example, two of the multiple base panels 14 constituting the flooring material 2.

[0034] As shown in Figures 3(A) and 3(B), the flooring material 2 comprises a top flooring material 11 and a plurality of base panels 14 provided below the top flooring material 11 (the surface to which the flooring material 2 is attached). The base panel 14 is a laminated body in which an underfloor material 12 and an intermediate material 13 are stacked. The base panels 14 are arranged, for example, in a matrix pattern on the surface to which the flooring material 2 is attached. The base panels 14 are arranged so that the underfloor material 12 faces the surface to which the flooring material 2 is attached and the intermediate material 13 faces the top flooring material 11.

[0035] Here, the overfloor material 11 is the same as the respective parts of the floor material 1 described in the first embodiment, and therefore description thereof will be omitted. Below, the base panel 14 composed of the underfloor material 12 and the intermediate material 13 will be described.

[0036] <Base Panel> As described above, the base panel 14 is a laminate formed by stacking a rectangular intermediate material 13 and a rectangular underfloor material 12. In each base panel 14, the outer periphery of the intermediate material 13 overlaps the outer periphery of the underfloor material 12 by two sides or less in a plan view. As shown in FIG. 4(A) , the intermediate material 13 of the base panel 14 is rectangular and has four sides 131 to 134 that form the periphery of the intermediate material 13. The underfloor material 12 of the base panel 14 is also rectangular and has four sides 121 to 124 that form the periphery of the underfloor material 12. Here, of the four sides of the floor underlayment material 12, the side positioned corresponding to side 131 of the intermediate material 13 is side 121, the side positioned corresponding to side 132 of the intermediate material 13 is side 122, the side positioned corresponding to side 133 of the intermediate material 13 is side 123, and the side positioned corresponding to side 134 of the intermediate material 13 is side 124.

[0037] In the base panel 14, which is a laminate of an intermediate material 13 and an underfloor material 12, it is preferable that the edges 131-134 forming the periphery of the intermediate material 13 and the edges 121-124 forming the periphery of the underfloor material 12 overlap by two sides or less in a plan view. Figure 3(A) shows an example of a configuration in which the edges 131-134 forming the periphery of the intermediate material 13 and the edges 121-124 forming the periphery of the underfloor material 12 overlap by zero in a plan view. Also, as shown in Figure 5(A), the base panel 14 of the flooring material 2 may be configured such that the underfloor material 12 and the intermediate material 13 of the same shape are stacked while being shifted in only one direction. That is, the base panel 14 of the flooring material 2 shown in Figure 5(A) shows an example of a configuration in which the sides 131-134 forming the periphery of the intermediate material 13 and the sides 121-124 forming the periphery of the underfloor material 12 overlap by two sides in plan view (sides 122 and 132, and side 124 and side 134). Furthermore, as shown in Figures 5(B) and 5(C), the flooring material 2 may include some base panels 14 in which the sides 131-134 forming the periphery of the intermediate material 13 and the sides 121-124 forming the periphery of the underfloor material 12 overlap by more than two sides in plan view. For example, as shown in Figures 5(B) and 5(C), at the position that is the end of the flooring material 2 (the periphery of the flooring material 2), a base panel 14 is placed in which the sides 131 to 134 that form the periphery of the intermediate material 13 overlap with the sides 121 to 124 that form the periphery of the floor underlayment material 12 by more than two sides in a planar view, and at a position other than the end of the flooring material 2, a base panel 14 is placed in which the sides 131 to 134 that form the periphery of the intermediate material 13 overlap with the sides 121 to 124 that form the periphery of the floor underlayment material 12 by two sides or less in a planar view.

[0038] The distance L1 (offset amount) in a plan view between the side 131 of the intermediate material 13 and the side 121 of the underfloor material 12 facing the side 131 of the intermediate material 13 can be determined as appropriate, but is preferably 20 mm or more. Similarly, the distance L2 in a plan view between the side 132 of the intermediate material 13 and the side 122 of the underfloor material 12, the distance L3 in a plan view between the side 133 of the intermediate material 13 and the side 123 of the underfloor material 12, and the distance L4 in a plan view between the side 134 of the intermediate material 13 and the side 124 of the underfloor material 12 are also preferably 20 mm or more. By having the distances L1 to L4 be 20 mm or more, good load-bearing properties are achieved, especially when a large load of 100 kg or more is applied.

[0039] <Effects of the Flooring Material According to the Present Disclosure> The flooring material according to the present disclosure described above has the following advantages in addition to the advantages (1) to (3) of the first embodiment. (4) The flooring material according to the present disclosure is composed of multiple base panels and the over-flooring material covering the base panels. The base panels are laminated bodies of rectangular intermediate materials and rectangular under-flooring materials. In each of the base panels, the outer periphery of the intermediate material preferably overlaps the outer periphery of the under-flooring material on two sides or less in plan view. This suppresses deformation of the outer periphery of the intermediate material even when a load is applied to the base panel, improving the load-bearing capacity of the flooring material. (5) In the flooring material according to the present disclosure, the distance between one side of the intermediate material in plan view of the base panel and the side of the under-flooring material opposite the side of the intermediate material preferably is 20 mm or more. This improves load-bearing capacity, especially when a large load of 100 kg or more is applied.

[0040] The flooring material according to the present disclosure will be described below with reference to examples, but the flooring material according to the present disclosure is not limited to these examples.

[0041] Example 1: A polyethylene foam (Asker C hardness 45, dimensions 600 mm x 600 mm x 6 mm thick) was used as the underfloor material, a hard polyvinyl chloride resin board (containing 70 wt% irregular calcium carbonate, ε (σmax) 0.9%, flexural modulus 8 GPa, dimensions 600 mm x 600 mm x 4 mm thick) was used as the intermediate material, and a long polyvinyl chloride resin sheet (dimensions 600 mm x 600 mm x 2 mm thick) was used as the top-floor material. The underfloor material, intermediate material, and top-floor material were laminated in this order using an adhesive to form the impact-absorbing flooring material of Example 1. Here, ε (σmax) is the strain (unit: %) at which bending strength is maximized in a three-point bending test according to JIS K7074.

[0042] Example 2 The impact-absorbing flooring material of Example 2 was formed in the same manner as Example 1, except that a hard polyvinyl chloride resin plate (containing 35 wt% of irregularly shaped calcium carbonate, ε (σmax) 2%, flexural modulus of elasticity 1.2 GPa, dimensions 600 mm × 600 mm × thickness 4 mm) with a different inorganic filler content was used as the intermediate material.

[0043] Example 3 The impact-absorbing flooring material of Example 3 was formed in the same manner as Example 1, except that a hard polyvinyl chloride resin plate (containing 70 wt% of scaly mica, ε (σmax) 3%, flexural modulus of elasticity 12 GPa, dimensions 600 mm × 600 mm × thickness 4 mm) was used as the intermediate material, with the material and content of the inorganic filler being changed.

[0044] Example 4 The impact-absorbing flooring material of Example 4 was formed in the same manner as in Example 1, except that a hard polyvinyl chloride resin plate (containing 35 wt% of scaly mica, ε (σmax) 6%, flexural modulus of elasticity 4 GPa, dimensions 600 mm × 600 mm × thickness 4 mm) was used as the intermediate material, with the material and content of the inorganic filler being changed.

[0045] <Example 5> The dimensions of the underfloor material were two types, (600 mm x 315 mm) and (600 mm x 285 mm), the dimensions of the intermediate material and the top-floor material were (600 mm x 300 mm), and the top-floor material was adhered to the base panel obtained by adhering the underfloor material and the intermediate material as shown in Figure 4. Except for this, the impact-absorbing floor material (2 pieces) of Example 5 was formed in the same manner as Example 1.

[0046] <Example 6> Impact-absorbing floor materials (two pieces) of Example 6 were formed in the same manner as in Example 5, except that the dimensions of the floor underlayment were two types: (600 mm x 325 mm) and (600 mm x 275 mm).

[0047] <Example 7> Impact-absorbing floor materials (two pieces) of Example 7 were formed in the same manner as in Example 5, except that the dimensions of the floor underlayment were two types: (600 mm x 350 mm) and (600 mm x 250 mm).

[0048] <Comparative Example 1> An impact-absorbing flooring material of Comparative Example 1 was formed in the same manner as in Example 1, except that a hard polyvinyl chloride resin board (containing 80 wt% of irregularly shaped calcium carbonate, ε (σmax) 0.4%, flexural modulus of elasticity 10 GPa, dimensions 600 mm × 600 mm × thickness 4 mm) with a different inorganic filler content was used as the intermediate material.

[0049] <Comparative Example 2> An impact-absorbing flooring material of Comparative Example 2 was formed in the same manner as in Example 1, except that a hard polyvinyl chloride resin board (containing 30 wt% of irregularly shaped calcium carbonate, ε (σmax) 2%, flexural modulus of elasticity 0.5 GPa, dimensions 600 mm × 600 mm × thickness 4 mm) with a different inorganic filler content was used as the intermediate material.

[0050] Comparative Example 3 An impact-absorbing floor material of Comparative Example 3 was formed in the same manner as in Example 1, except that a urethane rubber plate (Asker C hardness 45, dimensions 600 mm x 600 mm x thickness 6 mm) was used as the floor underlayment material.

[0051] [Evaluation] (Load-bearing capacity) The impact-absorbing floor materials of Examples 1 to 4 and the Comparative Example were cut into 300 mm x 600 mm rectangles, and two cut impact-absorbing floor materials were prepared. These impact-absorbing floor materials were laid and glued on a slate board (600 mm x 600 mm, 10 mm thick) to form a test specimen. In addition, impact-absorbing floor materials (600 mm x 600 mm) formed using two types of base panels of Examples 5 to 7 were placed on a slate board (600 mm x 600 mm, 10 mm thick) and glued to form a test specimen. As shown in FIG. 6, the test specimens formed in Examples 5 to 7 were configured by stacking a base panel 14, which was made of a floor underlayment material 12 and an intermediate material 13, and a floor covering material 11 on a slate board 100. In this case, the distance L5 (offset amount, see FIG. 4(C)) between the contact points between the intermediate materials and the contact points between the underfloor materials in the test specimens of Examples 5 to 7 was 15 mm in Example 5, 25 mm in Example 6, and 50 mm in Example 7. Furthermore, in the test specimens of Examples 5 to 7, the distance between the contact points between the intermediate materials and the contact points between the underfloor materials on the outer periphery of the test specimen was 0 around the entire periphery. The load-bearing capacity was evaluated based on the appearance of the flooring and intermediate materials after the caster test for each test specimen. The caster test conditions were as follows. Caster Test Conditions: In the Caster Resistance Test A-2 method in accordance with JIS A 1454:2016, the loads were 50 kg and 100 kg, and the test time was 3 hours. The 50 kg load is assumed to be the load per wheel of an electric bed, and the 100 kg load is assumed to be the load per wheel of a food delivery cart. Evaluation criteria The evaluation criteria for each of the caster tests with loads of 50 kg and 100 kg were as follows: Slight to no change in appearance of the flooring material and intermediate material: ○ Moderate change in appearance observed in the flooring material or intermediate material: △ Significant change in appearance observed in the flooring material or intermediate material: ×

[0052] (Impact absorption) The impact absorbing flooring materials of each example and comparative example were cut into 100 mm squares to prepare test specimens, and the impact load F (unit: N) was measured using the method described in JP 2020-076764 A using an impact load measuring device 200 shown in Figure 2. The impact load measuring device had the following specifications.・Measurement conditions Load cell: "TCLU-5A" manufactured by Tokyo Measuring Instruments Laboratory Co., Ltd. Accelerometer: Digital impact and vibration accelerometer "1340B" manufactured by Showa Sokki Co., Ltd. Measurement table: Surface plate size 750 mm x 1000 mm x 125 mm, weight 185 kg Weight main body: Material stainless steel Weight striking part: Material stainless steel, machined curvature radius R 100 mm Impactor: Weight Sw 5.85 kg (including accelerometer) Cushioning material: "Hitohada no Gel" (product name) manufactured by Exseal Co., Ltd., thickness 20 mm, Asker C hardness 7, Young's modulus 0.22 MPa ・Evaluation criteria Less than 3500 N (low risk of fracture in the elderly): ○ 3500 N to less than 5000 N (medium risk of fracture in the elderly): △ 5000 N or more (high risk of fracture in the elderly): × ・Judgment criteria ○ or △: Pass ×: Fail

[0053] Table 1 below shows the evaluation results of each example and comparative example.

[0054]

[0055] As shown in Table 1, the impact-absorbing flooring materials of Examples 1 to 4, which comprise a top-floor material, an underfloor material, and an intermediate material, the underfloor material having a foam structure, the intermediate material containing an inorganic filler, and in which the strain (ε(σmax)) at which bending strength is maximized in a three-point bending test according to JIS K7074 is 0.5% or more and the flexural modulus is 1 GPa or more, exhibited good impact absorption. The impact-absorbing flooring materials of Examples 1 to 4 also exhibited good load-bearing capacity under a load of 50 kg. The impact-absorbing flooring materials of Examples 2 to 4, which exhibited the above-mentioned strain (ε(σmax)) of 2% or more, also exhibited good load-bearing capacity under a load of 100 kg. Furthermore, the impact-absorbing flooring materials of Examples 3 and 4, which exhibited the above-mentioned strain (ε(σmax)) of 3% or more, exhibited even better impact absorption. Furthermore, in the impact-absorbing floor material of Example 4, in which the above-mentioned distortion (ε(σmax)) is 6% or more, there was little to no change in the appearance of the floor material and intermediate material, and the load-bearing capacity when subjected to a load of 100 kg was also good, at less than 3500 N.

[0056] Furthermore, in the impact-absorbing flooring materials of Examples 5 to 7, in which a distance L5 was set between line A relating to the intermediate material and line B relating to the floor underlayment material in the test specimen for the load-bearing test, Example 5 (distance L5 = 15 mm) had the same load-bearing capacity as Example 1, but Example 6 (distance L5 = 25 mm) showed improved load-bearing capacity, and Example 7 (distance L5 = 50 mm) was equivalent to Example 6.

[0057] The test specimens of Examples 5 to 7 are part of an impact-absorbing flooring material that is "composed of multiple base panels laid on the installation surface and floor coverings that cover the base panels, the base panels being a laminate of rectangular intermediate materials and rectangular underfloor materials, and in which the four sides of the intermediate materials of each base panel overlap with the four sides of the underfloor material in two or less places in a plan view." Among the test specimens of Examples 5 to 7, the test specimens of Examples 6 and 7 in particular showed improved load-bearing capacity, indicating that the impact-absorbing flooring material described above has particularly improved load-bearing capacity.

[0058] On the other hand, the impact-absorbing floor material of Comparative Example 1, in which the distortion (ε(σmax)) of the intermediate material is less than 0.5%, does not have sufficient load-bearing capacity, and the impact-absorbing floor materials of Comparative Example 2, in which the flexural modulus of the intermediate material is less than 1 GPa, and Comparative Example 3, in which the floor underlayment does not have a foam structure, do not have sufficient impact absorption.

[0059] Although the embodiments of the present disclosure have been described above, the above embodiments are merely examples of devices and methods for embodying the technical ideas of the present disclosure, and the technical ideas of the present disclosure do not specify the materials, shapes, structures, arrangements, etc. of the components. The technical ideas of the present disclosure can be modified in various ways within the technical scope defined by the claims.

[0060] REFERENCE SIGNS LIST 1 Floor material 11 Floor top material 12 Underfloor material 121, 122, 123, 124 Side 13 Intermediate material 131, 132, 133, 134 Side 14 Base panel 200 Impact load measuring device 210 Measurement table 220 Impact applying body 221 Weight 222 Striking part 230 Cushioning material 240 Load measuring means

Claims

1. An impact-absorbing flooring material comprising: a floor covering; an under-floor material provided below the floor covering; and an intermediate material provided between the floor covering and the under-floor material, wherein the under-floor material is formed from a resin material and has a foam structure; and the intermediate material is formed from a material containing a thermoplastic resin and an inorganic filler, and in a three-point bending test according to JIS K7074, the strain (ε (σmax)) at which the bending strength becomes maximum is 0.5% or more, and the bending modulus is 1 GPa or more.

2. The impact-absorbing flooring material according to claim 1, wherein the inorganic filler has a scaly, plate-like or fibrous shape.

3. The impact-absorbing floor material according to claim 1 or 2, wherein the strain ε (σmax) of the intermediate material is 3% or more.

4. An impact-absorbing flooring material as described in claim 1, which is composed of a plurality of base panels and the flooring material covering the base panels, wherein the base panels are laminated bodies in which the rectangular intermediate materials and the rectangular underfloor materials are stacked, and in each of the base panels, the overlap between the outer periphery of the intermediate materials and the outer periphery of the underfloor materials in a plan view is two sides or less.

5. The impact absorbing floor material according to claim 4, wherein the distance between one side of the intermediate material and one side of the floor underlayment material opposite to the one side of the intermediate material in a plan view of the base panel is 20 mm or more.

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