flooring

Abstract

This invention provides a flooring material with excellent impact absorption and load-bearing capacity. The flooring material comprises a top layer, a base layer formed of a soft material and disposed below the top layer, and an intermediate layer disposed between the top layer and the base layer. The intermediate layer is formed of a thermoplastic resin containing 40% to 85% by mass of calcium carbonate. The thickness of the intermediate layer is 3 mm to 5 mm, and the flexural stiffness per unit width is 15 Nm² to 90 Nm². The thickness of the base layer is 4 mm to 15 mm, and the Asker-C hardness of the base layer is 20 to 60.

Description

flooring This invention relates to flooring materials, and more particularly to flooring materials that can reduce the risk of fractures caused by falls, etc. In recent years, falls and fractures among the elderly have become a significant social problem, accounting for 10% of the main factors requiring care in this population. The location of fractures from falls varies greatly with age; the risk of femoral fractures increases dramatically after age 60. Femoral fractures often require hospitalization and prolonged immobility, leading to bone loss, worsening of the condition, and increased reliance on care. Furthermore, falls account for 20-25% of medical accidents. In kindergartens, daycare centers, and other certified childcare facilities, falls also account for over 20% of all falls. Therefore, there have been proposals to reduce fracture risk by using flooring materials that absorb the impact of falls (e.g., Patent Documents 1 and 2). In most cases, the impact-absorbing function of flooring is achieved by foaming the flooring itself or by laminating a soft layer of impact-absorbing foamed resin sheets onto the back side of the flooring. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent No. 3600726 [Patent Document 2] Japanese Patent No. 5244927 [The problem the invention aims to solve] However, when such flooring is used in facilities such as hospitals, the flooring is prone to deformation when heavy objects such as beds are placed on it, or when heavy objects with casters are moved on it, leading to problems with load-bearing capacity. Furthermore, in the event of a fall, the flooring at the point of impact may deform excessively, failing to provide sufficient impact absorption. This invention addresses these problems, aiming to provide flooring with excellent load-bearing capacity and impact absorption. [Means for solving the problems] To address the aforementioned issues, one embodiment of the flooring material of the present invention comprises a floor top material, a floor base material formed of a soft material disposed below the floor top material, and an intermediate material disposed between the floor top material and the floor base material. The intermediate material is formed of a thermoplastic resin containing 40% to 85% by mass of calcium carbonate, the thickness of the intermediate material is 3 mm to 5 mm, and the bending stiffness per unit width of the intermediate material is 15 Nm. 2 Above 90Nm 2 The following specifications apply: the thickness of the flooring substrate is 4mm to 15mm, and the Asker-C hardness of the flooring substrate is 20 to 60. [Effects of the Invention] According to the present invention, a ground sheet with excellent load-bearing capacity and impact absorption can be obtained. [The form in which the invention is carried out] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are examples of apparatuses and methods for embodying the technical concept of the present invention. Furthermore, the technical concept of the present invention can be modified in various ways within the technical scope described in the claims. <Basic Composition of Flooring Material> Hereinafter, referring to FIG1, the flooring material (hereinafter referred to as flooring material) 1 of the present invention will be described. The flooring material 1 includes a floor top material 11, a floor base material 12 disposed below the floor top material 11 (the mating surface of the flooring material 1), and an intermediate material 13 disposed between the floor top material 11 and the floor base material 12. The flooring material 1 has the function of suppressing femur fracture caused by the impact of a user, i.e., a person walking on the flooring material 1, falling. The floor top material 11 has surface functions such as improving the damage resistance and stain resistance of the floor board 1 and giving the floor board 1 a design feature. The floor base material 12 has the function of absorbing the pressure of a user falling, thereby improving the cushioning of the floor board 1. The intermediate material 13 acts as a support layer to distribute the load applied from the top floor material 11 to the base floor material 12, thereby improving impact absorption and load-bearing capacity. The flooring material 1 is constructed by layering the top floor material 11, intermediate material 13, and base floor material 12 in this order, which improves walkability and reduces the risk of femur fracture in case of a fall. The total thickness of the flooring slab 1 is preferably greater than 7mm and less than 22mm. When the total thickness of the flooring slab 1 exceeds 7mm, it becomes easier for pedestrians to achieve a balance between impact absorption, walking feel, and durability. However, when the total thickness of the flooring slab 1 is less than 22mm, the difference in height between it and the non-construction parts of the flooring slab 1 becomes too large, which can easily lead to construction problems. <Evaluation Method for Impact Absorption of Flooring Materials> Referring to Figure 2, the evaluation method for the impact absorption of flooring material 1 is described. The impact absorption of the flooring material is evaluated by measuring the "impact load F" obtained by simulating the impact load applied to the femur when falling on the flooring material. The impact load F is measured according to the method described in Japanese Patent Application Publication No. 2020-76764. As shown in Figure 2, the impact load measuring device 100 includes a measuring platform 110, an impact imprinter 120, a cushioning material 130, and a load measuring instrument 140. The impact imprinter 120 has a hammer 121 and a striking part 122. The hammer 121 has a mass that is applied to the trochanteric region of the femur according to the pressure distribution through a simulated fall, and the striking part 122 is formed to simulate the shape of the trochanteric region of the femur. The cushioning material 130 is formed of a material that simulates human soft tissue. The impact load F is measured by dropping an impactor 120 from a predetermined height corresponding to the simulated fall height onto the cushioning material 130 with the evaluation floor 140 (a floor 140 with the same structure as the floor 140 to be evaluated) positioned between the measuring platform 110 and the cushioning material 130, and measuring the maximum value of the load applied to the evaluation floor 140 during the fall using a load-bearing measurement device 150. Under the condition that the baseline impact load Fs generated when only the cushioning material is impacted without using the evaluation floor 1 is 5600N (the fall height of the impactor), the impact load F of the floor 1 is between 2000N and 4000N. When the impact load F is less than 2000N, the likelihood of a pedestrian losing balance and falling while walking on the floor 1 increases. When the impact load exceeds 4000N, the risk of femoral fracture due to a fall cannot be adequately suppressed. The following provides a detailed description of the floor top material 11, the floor base material 12, and the intermediate material 13. <Floor Top Material> The floor top material 11 is a layer forming the surface of the floor slab 1, and is formed of a rigid material compared to the floor base material 12. The thickness of the floor top material 11 should preferably be 5 mm or less. By keeping the thickness of the floor top material 11 to 5 mm or less, the weight of the floor slab 1 will not become excessive, reducing the burden during construction. This type of floor top material 11, as shown in Figure 1, may have a base layer 111, an image layer 112, and a protective layer 113. Furthermore, it is preferable that the floor top material 11 has at least a base layer 111. (Substrate Layer) Substrate layer 111 can be formed from wood-based substrates such as plywood, composite substrates mixed with wood flour and plastic, polyolefins such as polyethylene (PE) and polypropylene (PP), and rigid resin materials such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and vinyl chloride (PVC). Substrate layer 111 has the functions of providing a walking feel and adjusting elasticity, and can be appropriately set according to needs. (Image Layer) Image layer 112 is formed on the surface of substrate layer 111 opposite to the intermediate material 13. Image layer 112 is an ink layer for printing images such as wood grain and geometric patterns on substrate layer 111. Image layer 112 is a layer used to give the flooring 1 a design feature and can be appropriately set as needed. (Protective Layer) The protective layer 113 is formed on the surface of the image layer 112 opposite to the substrate layer 111. The protective layer 113 can be formed from resin materials such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), vinyl chloride (PVC), and acrylic resin. When the flooring 11 has an image layer 112, the protective layer 113 can be formed by allowing the image layer 112 to penetrate the surface of the flooring 1 through a transparent resin material. The protective layer 113 functions to protect the surface by improving durability such as chemical resistance, damage resistance, and dent resistance, and can be appropriately provided as needed. Methods for setting such floor top material 11 include, for example, using an adhesive to laminate onto the intermediate material 13, or performing thermal lamination on an extrusion molding production line of the intermediate material 13. <Floor Substrate> The floor substrate 12 is located below the floor top material 11 (on the side opposite to the surface of the floor top material 11). The floor substrate 12 can be formed of a material softer than the floor top material 11, and has the function of absorbing the impact on the floor board 1 by moderately deforming in the event of a fall. The floor substrate 12 has a foaming structure such as independent foaming or continuous foaming by methods such as chemical foaming, physical foaming, or supercritical foaming. The floor substrate 12 is preferably formed from a soft thermoplastic resin such as polyethylene (PE) or polypropylene (PP), polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), polystyrene (PS), polyurethane (PU), etc. Furthermore, the Asker C-type hardness of the floor substrate 12 is between 20 and 60. Here, "Asker C-type" refers to the hardness tester (spring-type hardness tester) specified by SRIS0101 (Japan Rubber Industry Association standard specification). In other words, "Asker C-type hardness" refers to the value obtained using the aforementioned Asker C-type hardness tester. When the Asker C-type hardness of the floor substrate 12 is less than 20, the deformation of the floor substrate 12 becomes excessive during walking and falls, leading to an increased risk of falls and fractures due to deteriorated walking performance and reduced cushioning effect. When the Asker C-type hardness exceeds 60, the deformation of the floor substrate 12 is insufficient, and adequate cushioning effect cannot be obtained. The thickness of the floor substrate 12 is between 4mm and 15mm. When the thickness is less than 4mm, it cannot provide sufficient cushioning in case of a fall. When the thickness exceeds 15mm, not only does the deformation of the floor substrate 1 due to load increase and the load-bearing capacity decrease, but the degree of sinking when walking also increases, increasing the risk of falling. <Intermediate Material> The intermediate material 13 serves as a support layer, distributing the load applied by the top layer 11 to the base layer 12, thereby improving the impact absorption and load-bearing capacity of the flooring 1. The intermediate material 13 is formed of thermoplastic resin and contains inorganic fillers. Furthermore, the intermediate material 13 has a foaming structure such as independent foaming or continuous foaming through chemical foaming, physical foaming, or supercritical foaming methods for weight reduction. The intermediate material 13 series is preferably a thermoplastic resin containing rigid materials such as polyethylene (PE) or polypropylene (PP) or polyvinyl chloride (PVC) as the base material. From the viewpoint of formability and versatility, it is more preferably to contain polyvinyl chloride (PVC). The intermediate material 13 contains 40% to 85% by mass of inorganic filler. When the inorganic filler content in the intermediate material 13 is less than 40% by mass, the flexural rigidity of the intermediate material 13 is insufficient, and the impact absorption of the flooring 1 is insufficient. Furthermore, when the inorganic filler content in the intermediate material 13 exceeds 85% by mass, the intermediate material 13 becomes brittle, and the possibility of breakage due to impact during use increases. As an inorganic filler, talc, silica, calcium carbonate, barium sulfate, aluminum hydroxide, carbon fiber, glass fiber, etc. can be used. Calcium carbonate is preferred as a general-purpose material with excellent processability. The bending stiffness per unit width of intermediate material 13 is 15 Nm. 2 Above 90Nm 2 The bending stiffness per unit width of intermediate material 13 is less than 15 Nm. 2 In this situation, the large bending degree of the localized impact during a fall fails to distribute the load effectively, resulting in insufficient impact absorption. Furthermore, the bending stiffness per unit width of the intermediate material 13 exceeds 90 Nm. 2 In such cases, insufficient bending during impact can lead to inadequate impact absorption. The thickness of the intermediate material 13 is between 3mm and 5mm. When the thickness of the intermediate material 13 is less than 3mm, the curvature of the intermediate material becomes too large when falling, and the impact dispersion effect cannot be obtained sufficiently. Furthermore, when the thickness of the intermediate material 13 exceeds 5mm, the impact dispersion effect cannot be obtained sufficiently because the curvature of the intermediate material 13 is insufficient, and the impact absorption effect of the floor slab 1 is easily insufficient in any situation. <Effects of the Flooring Material Disclosed Herein> The flooring material of the present invention described above has the following effects. (1) The flooring material of the present invention comprises: a floor top material, a floor base material formed of a soft material disposed below the floor top material, and an intermediate material disposed between the floor top material and the floor base material; the intermediate material is formed of a thermoplastic resin containing 40% to 85% by mass of inorganic filler, the thickness of the intermediate material is 3 mm to 5 mm, and the bending stiffness per unit width of the intermediate material is 15 Nm. 2 Above 90Nm 2 The following flooring substrates have a thickness of 4mm to 15mm and an Asker C-type hardness of 20 to 60. This results in flooring systems with excellent load-bearing capacity and impact absorption. (2) In the flooring material disclosed herein, the inorganic filler may include calcium carbonate. This makes it easy to form flooring material due to its high versatility and excellent processability. (3) Preferably, the flooring disclosed herein is designed such that, under the condition that the impact-generating body, whose weight and shape are based on the pressure distribution applied to the trochanter of the femur when a user falls, is dropped from a predetermined drop height equivalent to the user's waist height, and the reference impact load Fs generated when the impact is applied to the flooring through the cushioning material formed by simulating human soft tissue is 5600N, the impact load F generated when the impact-generating body is dropped from that drop height is between 2000N and 4000N. This reduces the likelihood of falling due to loss of balance while walking and significantly reduces the risk of femoral fracture caused by a fall. [Example] The following describes the ground material sheet disclosed herein through embodiments. However, the ground material sheet disclosed herein is not limited to these embodiments. <Example 1> Using an adhesive, an intermediate material (polyvinyl chloride resin board, calcium carbonate content 80% by mass, size 600mm × 600mm × thickness 7mm, Asker C hardness 40) was laminated onto a flooring substrate (polyethylene resin foam, size 600mm × 600mm × thickness 3mm, flexural stiffness 20Nm). 2 The flooring material (polyvinyl chloride resin sheet, size 600mm×600mm×thickness 2mm) and the floor top material form the flooring material of Example 1. <Example 2> Except that the thickness of the intermediate material is set to 4mm and the bending stiffness is set to 40Nm. 2 In addition, the same material as in Example 1 is formed as in Example 2. <Example 3> Except that the thickness of the floor substrate is set to 5mm, the flooring material of Example 3 is formed in the same manner as in Example 2. <Example 4> Except that the inorganic filler in the intermediate material was replaced with barium sulfate instead of calcium carbonate, the board material of Example 4 was formed in the same manner as in Example 2. <Example 5> Except that the barium sulfate content of the intermediate material is set to 85% and the bending stiffness of the intermediate material is set to 50 Nm. 2 In addition, the same material as in Example 4 is formed as in Example 5. <Example 6> Except that the thickness of the intermediate material is set to 5mm and the bending stiffness is set to 85Nm 2 In addition, the same material as in Example 1 is formed as in Example 6. <Example 7> Except that the Asker C-type hardness of the floor substrate is set to 55, the floor board of Example 7 is formed in the same manner as in Example 2. <Example 8> Except that the Asker C-type hardness of the floor substrate is set to 22, the flooring board of Example 8 is formed in the same manner as in Example 2. <Example 9> Except that the thickness of the floor substrate is set to 15mm, the flooring material of Example 9 is formed in the same manner as in Example 2. <Example 10> Except that the calcium carbonate content of the intermediate material is set to 45% and the bending stiffness is set to 15 Nm 2 In addition, the substrate of Example 10 is formed in the same manner as in Example 2. <Comparative Example 1> Except that the thickness of the intermediate material is set to 2 mm and the bending stiffness is set to 5 Nm 2 In addition, the same material as in Example 2 was formed as in Comparative Example 1. <Comparative Example 2> Except that the thickness of the intermediate material is set to 6 mm and the bending stiffness is set to 140 Nm 2 In addition, the same material as in Example 2 was formed as in Comparative Example 2. <Comparative Example 3> Except that the barium sulfate content of the intermediate material is set to 87% and the bending stiffness is set to 55 Nm 2 In addition, the same material as in Example 4 was formed as in Comparative Example 3. <Comparative Example 4> Except for replacing the inorganic filler in the intermediate material with barium sulfate instead of calcium carbonate, setting the calcium carbonate content to 35%, and setting the flexural stiffness to 10 Nm, 2 In addition, the material of Comparative Example 3 was formed in the same manner as in Example 2. <Comparative Example 5> Except that the Asker C-type hardness of the floor substrate was set to 65, the floorboard of Comparative Example 5 was formed in the same manner as in Example 2. <Comparative Example 6> Except that the Asker C-type hardness of the floor substrate was set to 18, the floorboard of Comparative Example 6 was formed in the same manner as in Example 2. <Comparative Example 7> Except that the thickness of the floor substrate is set to 3 mm, the flooring material of Comparative Example 7 is formed in the same manner as in Example 2. <Comparative Example 8> Except that the thickness of the floor substrate is set to 20 mm, the flooring material of Comparative Example 8 is formed in the same manner as in Example 2. [Evaluation] (Impact Absorption) The soil plates of each embodiment and comparative example were cut into 100mm squares to form test specimens. The impact load F was measured using the method described in Japanese Patent Application Publication No. 2020-076764. • Measurement Conditions: Loading unit: "TCLU-5A" manufactured by Tokyo Instrument Research Institute Co., Ltd.; Impact radius of curvature R: 100mm; Impact recipient mass: 5.85kg; Impact recipient drop height: 50cm; Cushioning material: EXSEAL Co., Ltd. "Human Muscle Gel", 20mm thick, Asco C-type hardness 7. • Evaluation Criteria: 2000N≦Fs≦3400N: ○ (Pass) 3400N<Fs≦4000N: △ (Pass) 4000N<Fs: × (Fail) (Load Resistance) The flooring materials of the examples and comparative examples were cut into 300mm × 600mm rectangles. Two cut flooring materials were prepared, and these test pieces were arranged on a calcium silicate board (600mm × 600mm, 12mm thick) and bonded together to form test pieces. Load resistance was evaluated by the appearance of the flooring materials and intermediate materials after a caster test on each test piece. The caster test conditions are as follows: • Caster test conditions: steel wheels (100mm diameter, 30mm width), load of 100kgf, 500 reciprocating cycles in a direction perpendicular to the boundary of the two flooring materials • Slight to no appearance change in the evaluation reference flooring materials and intermediate materials: ○ (Pass) Moderate appearance change observed in the flooring materials or intermediate materials: △ (Pass) Significant appearance change observed in the flooring materials or intermediate materials: × (Fail) The evaluation results of the various embodiments and comparative examples are shown in Table 1 below. [Table 1] As shown in Table 1, the floor comprises a top layer, a base layer, and an intermediate layer. The inorganic filler content in the intermediate layer is 40% to 85% by mass, the thickness of the intermediate layer is 3mm to 5mm, and the bending stiffness per unit width is 15Nm. 2 Above 90Nm 2 In the following embodiments, the thickness of the floor substrate is 4mm to 15mm, and the Asker C-type hardness is 20 to 60 or higher, all of which are characterized by good impact absorption and load-bearing capacity. On the other hand, the flooring materials of Comparative Example 1 (with an intermediate material thickness of less than 3 mm) and Comparative Example 2 (with an intermediate material thickness of more than 5 mm) exhibited lower impact absorption. Furthermore, the flooring material of Comparative Example 3 (with an inorganic filler content of more than 85% by mass in the intermediate material) showed sufficient impact absorption but insufficient load-bearing capacity. Also, the flooring material of Comparative Example 3 (with an inorganic filler content of less than 40% by mass in the intermediate material) showed sufficient load-bearing capacity but insufficient impact absorption. Furthermore, the flooring materials of Comparative Example 5 (with an Asker C-type hardness exceeding 60) and Comparative Example 6 (with an Asker C-type hardness less than 20) showed insufficient impact absorption. Moreover, the flooring material of Comparative Example 7 (with a flooring material thickness less than 4 mm) also showed insufficient impact absorption. On the other hand, while the flooring material of Comparative Example 8 (with a flooring material thickness exceeding 15 mm) showed sufficient impact absorption, its load-bearing capacity was insufficient. Therefore, the flooring material disclosed herein is formed by using a core material composed of thermoplastic resin containing 40% to 85% by mass of calcium carbonate, with a core material thickness of 3 mm to 5 mm, and a flexural stiffness per unit width of 15 Nm. 2 Above 90Nm 2 The following flooring base material has a thickness of 4mm to 15mm, an Asker C-type hardness of 20 to 60, and excellent load-bearing capacity and impact absorption. The above description illustrates the embodiments of this disclosure. These embodiments are merely examples of devices and methods used to concretize the technical concept of this disclosure. The technical concept of this disclosure does not define the material, shape, structure, or arrangement of the constituent parts. The technical concept of this disclosure can be modified in various ways within the technical scope defined by the claims described in the patent application. 1: Flooring material 11: Flooring base material 12: Intermediate material 13: Flooring top material 100: Impact load measuring device 110: Measuring platform 111: Substrate layer 112: Image layer 113: Protective layer 120: Impact bearing 121: Hammer 122: Impact part 130: Cushioning material 140: Load measuring method Figure 1 is a cross-sectional view showing an example of the positional configuration of the grounding material disclosed herein. Figure 2 is a schematic diagram illustrating the impact load measuring device used in the evaluation of impact-absorbing grounding materials. 1: Flooring 11: Floor base material 12: Intermediate material 13: Floor top material 111: Substrate layer 112: Image Layer 113: Protective layer

Claims

1. A flooring material comprising: a floor top layer, a floor base layer formed of a soft material disposed below the floor top layer, and an intermediate layer disposed between the floor top layer and the floor base layer, the intermediate layer being formed of a thermoplastic resin containing 40% to 85% by mass of inorganic filler, the intermediate layer having a thickness of 3 mm to 5 mm, the intermediate layer having a flexural stiffness per unit width of 15 Nm² to 90 Nm², the floor base layer having a thickness of 4 mm to 15 mm, and the floor base layer having an Asker C-type hardness of 20 to 60.

2. The substrate as requested in claim 1, wherein the inorganic filler comprises calcium carbonate.

3. The flooring as requested in item 1 or 2, wherein, under the condition that the impact-generating body, whose weight and shape are based on the pressure distribution applied to the trochanter of the femur when the user falls, is dropped from a predetermined drop height equivalent to the user's waist height, and the reference impact load Fs generated when the impact is applied to the cushioning material formed by simulating human soft tissue is 5600N, the impact load F generated when the impact-generating body is dropped from the drop height through the cushioning material to the flooring is 2000N to 4000N.

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