JP7600620B2 - Shock absorbing flooring - Google Patents

Description

The present invention relates to a shock-absorbing flooring material that can prevent femoral fractures caused by the impact of a fall, for example, in elderly people or small children, and is used in hospitals, elderly care facilities, childcare facilities, etc.

At present, falls and fractures among the elderly have become a social problem, accounting for 10% of the causes of elderly people needing nursing care.Fractures from falls also account for 20% to 25% of medical accidents.
The location of fractures caused by falls varies by age, with the risk of hip fractures increasing sharply after the age of 60.
Femoral fractures require hospitalization for treatment and result in the inability to walk for long periods of time, which can lead to a decrease in bone mass and a worsening of the symptoms, making the patient more likely to require nursing care.
Additionally, in childcare facilities (kindergartens, nursery schools, certified childcare centers), accidents resulting in fractures due to falls account for just over 20% of all accidents in the three layers mentioned above.

Because of the problems mentioned above, flooring materials have been invented that absorb shock in the event of a fall and reduce the risk of fractures.
For example, flooring materials used in hospitals and elderly care facilities are generally in the form of wide sheets known as long sheets, and in order to impart shock absorption to these flooring materials, the sheets themselves may be foamed (see paragraph [0040] and Figure 3 of Patent Document 1), or a shock-absorbing foamed resin sheet may be laminated on the base (see paragraph [0025] and Figures 1 and 3 of Patent Document 2).
On the other hand, the flooring materials used in hospitals and elderly care facilities are generally wide sheet-shaped flooring materials called long sheets. In order to impart shock absorption to these flooring materials, the sheets themselves may be foamed or a foamed resin sheet for shock absorption may be laminated on the base.

Patent No. 3600726 Patent No. 5244927

However, while many of the flooring materials that use the foaming agents described above have a soft layer to absorb shock, there is a problem in that when heavy objects such as beds are placed on the floor in hospitals or when heavy objects are rolled on casters, the soft layer can be crushed and dented.
Therefore, an object of the present invention is to provide an impact absorbing floor material that has the absorption effect of a soft material, while also having durability such as static load resistance and dynamic load resistance.

The shock-absorbing flooring material according to one aspect of the present invention is a shock-absorbing flooring material that prevents fractures of the femur caused by the shock of a user falling over, and is made up of three layers: an upper flooring material made of a hard material, an underfloor material made of a soft material provided below the upper flooring material, and an intermediate layer located between the upper flooring material and the underfloor material. The underfloor material has a thickness of 4 mm to 10 mm, and when a static compression test is conducted to measure the test force and displacement, the compressive strain of the underfloor material when absorbing 5 J of energy is within 0.8.

Furthermore, the impact absorbing floor material according to one embodiment of the present invention is characterized in that, when the static compression test is carried out, the compression test force at 50% strain is 1200N or more and 1800N or less.
The impact absorbing floor material according to one aspect of the present invention is characterized in that the thickness of the intermediate layer is 1 mm or more and 3 mm or less, and the bending stiffness per unit width is 0.1 ^Nm2 or more and 10.0 ^Nm2 or less.
The impact absorbing floor material according to one embodiment of the present invention is characterized in that the thickness of the floor covering material is 2 mm or more and 10 mm or less, and the overall thickness of the three layers is 5 mm or more and 20 mm or less.

The shock-absorbing flooring material according to one aspect of the present invention is characterized in that, under conditions set so that a standard impact load Fs is 6500N when an impact-applying object having a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls is dropped from a drop height based on the height of the user's waist and an impact is applied to a cushioning material made of a material simulating human soft tissue, the impact load F generated when the impact-applying object is dropped from the drop height and an impact is applied to the shock-absorbing flooring material through the cushioning material is 2000N or more and 5000N or less.

The impact absorbing floor material according to one aspect of the present invention is characterized in that the cushioning material has a dynamic viscoelasticity Tan δ of 0.1 or more and 0.7 or less at 25° C. and a measurement frequency of 1 Hz.
The impact absorbing floor material according to one aspect of the present invention is characterized in that the thickness of the cushioning material is 7 mm or more and 80 mm or less.

According to one aspect of the present invention, it is possible to provide an impact absorbing flooring material that has the absorption effect of soft materials while also having durability such as static load resistance and dynamic load resistance.

1 is a cross-sectional view showing the components of the impact absorbing floor material according to the first embodiment, arranged separately from each other. FIG. FIG. 2 is a schematic diagram of a static compression testing machine used to measure impact absorbing floor materials. FIG. 11 is an explanatory diagram for explaining the relationship between a test force and a displacement.

(Embodiment 1)
A first embodiment of the present invention will be described below with reference to the drawings.
Here, the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. differ from the actual ones. Furthermore, the embodiments shown below are examples of configurations for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the materials, shapes, structures, etc. of the components described below. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

In Figure 1, reference numeral 10 denotes an impact absorbing flooring material. The impact absorbing flooring material 10 can prevent femur fractures caused by the impact of a fall, for example, by elderly people or small children, and is used in hospitals, elderly care facilities, childcare facilities, etc.
As shown in FIG. 1, the shock absorbing floor material 10 is composed of the following layers:
The following layers will be described later.
(1) Floor covering 20
(2) Floor underlayment material 30
(3) Intermediate layer 40
(4) Pattern layer 50
(5) Surface protective layer 60
In addition, the layers of the impact absorbing floor material 10 are not limited to the above (1) to (5), and it is also possible to omit either the pattern layer 50 or the surface protection layer 60 to make it four layers, or to omit both to make it three layers.

(Flooring material 20)
The floor covering 20 constitutes the floor surface on which users walk and is made of a hard material.
The floor covering 20 is made of a hard material such as a wood base material such as plywood, a composite base material made of a mixture of wood powder and plastic, or a resin base material such as polyolefins such as polyethylene (PE) and polypropylene (PP) or polyvinyl chloride (PVC).

(Thickness of floor covering 20)
The thickness of the floor covering 20 is not less than 2 mm and not more than 10 mm.
If the thickness of the floor covering 20 is less than 2 mm, the rigidity decreases, and if it exceeds 10 mm, the rigidity is too high and the shock absorption properties decrease.

(Floor underlayment 30)
The underfloor material 30 is located below the top floor material 20, constitutes a shock absorbing portion that absorbs shock, and is made of a soft material.
The floor underlayment material 30 is a foam material made of soft materials such as resins such as polyolefin, PVC, ethylene vinyl acetate copolymer (EVA), polystyrene (PS), polyurethane (PU), etc., and has a foam structure such as independent foam or continuous foam produced by methods such as chemical foaming, physical foaming, and supercritical foaming.

(Thickness of the floor underlayment 30)
The thickness of the underfloor material 30 is, for example, 4 mm or more and 10 mm or less.
If the thickness of the underfloor material 30 is less than 4 mm, the shock absorbing properties will decrease, and if it exceeds 10 mm, the floor will sink significantly, which may cause an inconvenience when walking.

(Intermediate layer 40)
The intermediate layer 40 is located between the over-floor material 20 and the under-floor material 30, is made of a hard material, and acts as a support layer to distribute the load applied from the over-floor material 20 to the under-floor material 30, thereby improving durability such as dynamic load resistance and static load resistance.
The intermediate layer 40 is made of a hard material such as a wood base material such as plywood, a polyolefin such as polyethylene (PE) or polypropylene (PP), or a resin base material such as polyvinyl chloride (PVC).

(Thickness of intermediate layer 40 and bending rigidity per unit width)
The thickness of the intermediate layer 40 is 1 mm or more and 3 mm or less. If the thickness of the intermediate layer 40 is less than 1 mm, the durability is poor, and if the thickness exceeds 3 mm, the weight is heavy.
The intermediate layer 40 has a bending stiffness per unit width of 0.1 Nm ² or more and 10.0 Nm ² or less.
If the bending stiffness per unit width of the intermediate layer 40 is less than 0.1 ^Nm2 , the stiffness will be insufficient and the improvements in durability and shock absorption properties that can be achieved by the three-layer structure will not be expected. If it exceeds 10.0 ^Nm2 , the stiffness will be too high, and fatigue during walking may increase.
As long as the bending stiffness is within the above-mentioned range, the base material of the intermediate layer 40 can be foamed in order to reduce the weight.

(Total thickness of the three layers)
The total thickness of the three layers, including the thickness of the floor covering material 20, the underfloor material 30 and the intermediate layer 40, is 5 mm or more and 20 mm or less.
If the total thickness of the three layers is less than 5 mm, it is impossible to achieve a balance between shock absorption, walking comfort, and durability, and if it exceeds 20 mm, it will be too thick for long PVC (usually 2 to 3 mm), and there is a possibility that it will not fit well when installed.

(Pattern Layer 50)
The pattern layer 50 is located on the surface of the floor covering 20 and provides a design, and is provided appropriately as required.
The pattern layer 50 is a sheet made of the same material as the floor covering 20, such as polyolefin or PVC, on which a pattern such as wood grain or a geometric pattern is applied.

(Surface protective layer 60)
The surface protective layer 60 is positioned on the surface of the design layer 50 and serves to protect the surface so as to improve durability such as chemical resistance, scratch resistance, and dent resistance.
The surface protection layer 60 is made of an acrylic coating, transparent PVC, or the like.
In addition, the surface of the surface protection layer 60 may be embossed (embossed with an embossing plate to create a concave-convex shape). By embossing the surface of the impact absorbing floor material 10, a three-dimensional feel can be created.
Although not shown, embossed patterns include, for example, duct grooves in wood grain boards, unevenness on the surface of a stone slab, textured cloth surface, matte finish, sand grain, hairline, and linear grooves.

(Method of manufacturing the impact absorbing floor material 10)
The impact absorbing floor material 10 has the above-mentioned configuration and is manufactured as follows.
An intermediate layer 40 made of a hard material is provided between a floor covering material 20 made of a hard material and a floor underlay material 30 made of a soft material provided below the floor covering material 20.
A pattern layer 50 is laid on the upper surface of the floor covering 20, and a surface protection layer 60 is further laid on the upper surface of the pattern layer 50 to manufacture the impact absorbing floor covering 10.

(Absorbed Energy)
When the floor underlayment 30 is subjected to a static compression test described in the next section, the compression strain of the floor underlayment 30 when 5 J of energy is absorbed is 0.8 or less.
If the value exceeds 0.8, the foam layer of the underfloor material 30 will absorb the energy and cause the floor to sink significantly, which may cause an adverse effect on the walking feel.
Here, the "compressive strain" is "compressive strain = thickness after deformation (mm) / thickness before deformation (mm)".

(Static Compression Test Method)
The compressive strain when 5 J of energy is absorbed is measured using the following "static compression test."
The static compression test is carried out using a static compression tester 100 as shown in FIG. 2 under the following conditions.
(1) Size of sample 120: 100 mm square (2) Size of compressed terminal 130: 50 mm square (3) Compression speed: 10 m/min
The sample 120 is placed on the test stand 110, a compression terminal 130 is placed at the center of the sample 120, and the test force and displacement are measured as the sample 120 is gradually compressed.

The absorbed energy is represented by the area under the load-displacement SS curve obtained in a static compression test, as shown in FIG. 3 (see FIG. 3).
The absorbed energy is obtained by integrating the load.
The compressive strain of the floor underlayment when absorbing 5 J of energy is set to 0.8 or less. However, if the displacement is 8 mm or more, the floor will sink significantly in order to absorb the energy, which may cause an adverse effect on the feeling of walking.

(Compression test force at 50% strain)
When a static compression test is carried out under the above conditions, the impact absorbing floor material 10 has a compression test force of 1200N or more and 1800N or less at 50% strain.
If the test force exceeds 1,800 N, the floor underlayment 30 (shock absorbing material) will be less likely to deform when subjected to a large impact, and may not be able to adequately absorb the impact when a large impact is applied.
If the test force is less than 1200 N, the floor is easily deformed and may deform even with normal walking, which may actually lead to a fall.

(Shock load)
The impact absorbing floor material 10 is designed such that, under the following conditions, the impact load F generated when an impact applying object is dropped from a drop height and an impact is applied to the floor material via the cushioning material is 2000N or more and 5000N or less.
The above conditions are set so that an impact-applying object having a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls is dropped from a drop height based on the height of the user's waist, and an impact is applied to a cushioning material made of a material simulating human soft tissue, resulting in a standard impact load Fs of 6,500 N.
If the impact load F is less than 2000 N, the impact absorption capacity will be too strong, making walking difficult, which is undesirable, and if it exceeds 5000 N, the impact absorption capacity will be weak, making it difficult to adequately address the risk of femoral fracture, which is also undesirable.

(Cushioning material)
The above-mentioned buffer material has a dynamic viscoelasticity Tan δ of 0.1 or more and 0.7 or less at 25° C. and a measurement frequency of 1 Hz.
The cushioning material has a thickness of 7 mm to 80 mm.

(Actions and Effects of the First Embodiment)
The effects and advantages of the embodiment are as follows.
(1) According to this embodiment 1, the underfloor material 30 has a thickness of 4 mm or more and 10 mm or less. When a static compression test is conducted to measure the test force and displacement, the compressive strain of the underfloor material 30 when 5 J of energy is absorbed is within 0.8. This makes it possible to provide an impact absorbing floor material that has the absorption effect of a soft material while also having durability such as static load resistance and dynamic load resistance.
If the thickness of the underfloor material 30 is less than 2 mm, the shock absorbing properties will decrease, and if it exceeds 10 mm, the floor will sink significantly, which may cause an inconvenience when walking.
If the compressive strain of the floor underlayment 30 when absorbing 5 J of energy exceeds 0.8, the floor will sink significantly in order to absorb the energy, which may cause an adverse effect on the walking sensation.

(2) In the first embodiment, when a static compression test is performed, the compression test force at 50% strain is 1200 N or more and 1800 N or less.
If the test force exceeds 1,800 N, the floor underlayment 30 (shock absorbing material) will be less likely to deform when subjected to a large impact, and may not be able to adequately absorb the impact when a large impact is applied.

(3) According to the first embodiment, the thickness of the intermediate layer 40 is equal to or greater than 1 mm and equal to or less than 3 mm, and the bending stiffness per unit width is equal to or greater than 0.1 Nm ² and equal to or less than 10.0 Nm ² .
If the thickness of the intermediate layer 40 is less than ¹ mm/0.1 Nm2, the rigidity and thickness will be insufficient, and the improvement in durability and shock absorption properties that can be achieved by making it three-layered will not be expected. If the thickness exceeds 10.0 ^Nm2 , the rigidity will be too high, and fatigue during walking may increase.

(4) In this embodiment 1, the floor covering material 20 has a thickness of 2 mm or more and 10 mm or less, and the overall thickness consisting of the three layers is 5 mm or more and 20 mm or less. If the thickness of the floor covering material 20 is less than 2 mm, the rigidity decreases, and if it exceeds 10 mm, the rigidity is too high and the impact absorption properties decrease.
If the total thickness of the three layers is less than 5 mm, it is impossible to achieve a balance between shock absorption, walking comfort, and durability, and if it exceeds 20 mm, it will be too thick for long PVC (usually 2 to 3 mm), and there is a possibility that it will not fit well when installed.

(5) In this embodiment 1, an impact-applying object having a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls is dropped from a drop height based on the height of the user's waist, and the standard impact load Fs generated when the impact is applied to a cushioning material made of a material that mimics human soft tissue is set to be 6,500 N. When the impact-applying object is dropped from the drop height and an impact is applied to the shock-absorbing flooring 10 through the cushioning material, the impact load F generated is 2,000 N or more and 5,000 N or less.
If the impact load F is less than 2000 N, the impact absorption capacity will be too strong, making walking difficult, which is undesirable, and if it exceeds 5000 N, the impact absorption capacity will be weak, making it difficult to adequately address the risk of femoral fracture, which is also undesirable.

(6) In the first embodiment, the buffer material has a dynamic viscoelasticity Tan δ of 0.1 or more and 0.7 or less at 25° C. and a measurement frequency of 1 Hz.
(7) In the first embodiment, the cushioning material has a thickness of 7 mm or more and 80 mm or less.

The present invention will be specifically explained below with reference to Examples 1 to 3 and Comparative Examples 1 to 3. However, the present invention is not limited to the following Examples 1 to 3.

Example 1
The main conditions of Example 1 are as shown in Table 1 below.
In addition, the following Table 1 shows the conditions of Example 1, as well as Examples 2, 3, and Comparative Examples 1 to 3.

In Example 1, as shown in Table 1 above, the size of the drop surface of the evaluation flooring material was 10,000 ^mm2 , a polyvinyl chloride resin flooring material with a thickness of 2 mm and a bending rigidity per unit width of 0.07 ^Nm2 was used as the top floor material, a polyvinyl chloride resin foam with a thickness of 5 mm, C hardness of 60 and an expansion ratio of 5 times was used as the underfloor material, and a rigid polyvinyl chloride resin board with a thickness of 2 mm and a bending rigidity of 0.51 N· ^m2 was used as the intermediate layer to produce the impact absorbing flooring material of Example 1.

Example 2
In Example 2, as shown in Table 2, an impact-absorbing floor material for Example 2 was produced in the same manner as in Example 1, except that the floor underlayment was a PE resin foam with a thickness of 6.5 mm, a C hardness of 50, and an expansion ratio of 10 times.
Example 3
In Example 3, as shown in Table 2, an impact absorbing floor material of Example 3 was produced in the same manner as in Example 2, except that the floor covering material had a thickness of 3 mm and a bending rigidity per unit width of 0.5 ^Nm2 .

(Comparative Example 1)
In Comparative Example 1, the intermediate layer was not laminated, and the floor was made of a two-layer structure consisting of a floor covering material and an underfloor material, as shown in Table 2. Otherwise, the impact absorbing floor material of Comparative Example 1 was produced in the same manner as in Example 2.
(Comparative Example 2)
In Comparative Example 2, as shown in Table 2, an impact absorbing floor material for Comparative Example 2 was produced in the same manner as in Example 1, except that the intermediate layer was made of a hard polyvinyl chloride resin board having a thickness of 0.5 mm and a bending rigidity per unit width of 0.03 ^Nm2 .
(Comparative Example 3)
In Comparative Example 3, as shown in Table 2, an impact absorbing floor material of Comparative Example 3 was produced in the same manner as in Example 3, except that the thickness of the floor underlayment was 3 mm.

(Evaluation items)
The evaluation items are as follows:
The following evaluation items will be described later.
(1) Strain at absorbing 5J (2) Compressive test force at 50% strain [N]
(3) Impact load (N/judgement)
(4) Durability (5) Overall evaluation

(Strain when absorbing 5J)
The strain at absorbing 5 J was measured using a static compression test method under the following conditions.
A sample of 100 x 100 mm is prepared, and a terminal of 50 mm square is placed on top of it.
The specimen was compressed at a compression speed of 10 mm/min using an autograph (AGS-500NX, manufactured by Shimadzu Corporation), and the test force and displacement were measured.
When absorbing 5 J, a compressive strain of 0.8 or less was judged to be acceptable, and any other value, that is, a value exceeding 0.8, was judged to be unacceptable.
The dynamic viscoelasticity Tan δ and the complex modulus of elasticity E* of the floor underlayment were measured using a dynamic viscoelasticity measuring device "DMA8000" (model number) manufactured by PerkinElmer Co., Ltd. at 25°C and a measurement frequency of 1 Hz in compression mode.

(Compression test force at 50% strain)
The compressive test force at 50% strain was measured when a static compression test was carried out.
The compressive test force at 50% strain was judged as pass if it was 1200N or more and 1800N or less, and was judged as fail if it was any other than that.

(Measurement of impact load)
The impact load was measured using a method for simulating the impact load applied to a user's femur when the user falls on a floor material (hereinafter referred to as the "present impact load method"; see Patent Application No. 2019-192234).
This measurement method involves placing a cushioning material made of a material that simulates human soft tissue on top of an evaluation flooring material made of the same material as the flooring material, a weight based on the pressure distribution applied to the trochanter of the femur due to a simulated fall, and an impact part formed in a shape that simulates the trochanter, and dropping the integrated weight and impact part at a predetermined drop height based on the height of the simulated fall, so that the weight applies an impact to the evaluation flooring material with the impact part in contact with the cushioning material, and the impact load generated on the evaluation flooring material is measured by a load measuring means.
The impact load measuring method will be described later.

(Device specifications)
The specifications of the device used in this impact load measurement method are as follows:
(1) Load cell: "TCLU-5A" (model number) manufactured by Tokyo Measuring Instruments Laboratory Co., Ltd.
(2) Accelerometer: Showa Sokki Co., Ltd. digital shock and vibration accelerometer "1340B" (model number)
(3) Measurement table/plate size: 750mm x 1000mm x 125mm Weight: 185kg
(4) Weight body: Material: Stainless steel (5) Weight striking part: Material: Machined stainless steel Curvature radius R: 100 mm
(6) Impactor/weight Sw: 5.85 kg (including accelerometer)
(7) Impactor/weight Sw: 5.85 kg (including accelerometer)
(8) Cushioning material: "Human Skin Gel" (product name) manufactured by Exseal Co., Ltd.
(9) Thickness: 20 mm Asker C hardness: 7 Young's modulus: 0.22 MPa
(10) Dynamic viscoelasticity Tan δ: 0.24 (25 ° C, measurement frequency 1 Hz)

(Judgment of impact load)
The impact load is judged as follows.
(1) If the fracture level is 2,110N or less (low fracture risk for all age groups), the rating is "◎" (double circle), and the patient passes.
(2) If it is over 2,110 and 3,440 or less (low risk of fracture in the elderly), the answer is “O” and the person passes.
(3) If it is over 3,440 and 5,000 or less (medium risk of fracture in the elderly), it is marked as "△" and is a pass.
(4) If it is more than 5,000 and less than 7,200 (high risk of fracture in the elderly), it is marked as "X" and the rest are failures.
(5) If it is over 7,200 (high fracture risk for all age groups), the grade is “XX” (two “X”s) and the person fails.

(Durability)
In the durability test, a load of 20 kg was applied from above a resin caster having a width of 20 mm and a diameter of 50 mm, and the caster was made to reciprocate 3,000 times.
After unloading, the appearance and dents were visually inspected.
The durability was evaluated as follows.
(1) If the dent recovery rate is 95% or more one week after the load is removed and there are no abnormal marks or the like that are visually observed, the product is evaluated as "○" and passes the test.
(2) If the dent recovery rate is less than 95% or if there are any abnormal marks when visually observed, the product is marked as "X" and is unsatisfactory.

(comprehensive evaluation)
The overall evaluation is as follows:
(1) If all evaluation items are passed, the mark is “○” and the item is passed.
(2) In cases other than (1) above, that is, when one or more of the evaluation items are not met, the result is "X" and the item is not met.

(Evaluation Results)
The results are shown in Table 2.

As shown in Table 2 above, Examples 1 to 3 passed the overall evaluation.
In contrast, all of Comparative Examples 1 to 3 were unsatisfactory.
In Comparative Examples 1 and 2, the compressive strain of the floor underlayment when absorbing 5 J exceeded 0.8, which was too high, and the compressive test force at 50% strain was less than 1200 N, which was too low.
In Comparative Example 1, as shown in Table 1, this is believed to be due to the absence of an intermediate layer, and it can be inferred that the intermediate layer is essential.
As shown in Table 1, in Comparative Example 2, the cause was that the thickness of the intermediate layer was 0.5 mm, which was too thin, and it can be inferred that the thickness of the intermediate layer needs to exceed 0.5 mm.
In Comparative Example 3, the compressive test force at 50% strain exceeded 1800 N, which was too high, and the impact load exceeded 5000, which was too high.
As shown in Table 1, in Comparative Example 3, the thickness of the underfloor material was 3 mm, which was too thin, and it can be inferred that the thickness of the intermediate layer of the underfloor material needs to exceed 3 mm.

(Method of measuring impact load)
The present impact load measurement method has the following features:
(1) The weight at the time of impact and the drop height are set so that the impact energy when the weight impacts the evaluation flooring material is 5 J or more and 50 J or less, and preferably 20 J or more and 40 J or less.
(2) Select cushioning materials based on the user's height, weight, age, and gender.
(3) The cushioning material to be selected has an Asker C hardness of more than 0 and less than 16, preferably 5 or greater and 10 or less.

(4) The cushioning material is selected such that the dynamic viscoelasticity value tan δ of the human soft tissue at a measurement frequency of 1 Hz is 0.1 to 0.7, preferably 0.2 to 0.50.
(5) The cushioning material is selected so that the impact load generated when the cushioning material is placed on a rigid measurement table and a weight is dropped on the cushioning material to apply an impact thereto is 3,500 N or more and 10,000 N or less, preferably 5,000 N or more and 8,000 N or less.
(6) The buffer material to be selected has a Young's modulus of 0.05 MPa or more and 0.80 MPa or less, and preferably 0.1 MPa or more and 0.5 MPa or less.

(7) The cushioning material should have a thickness of 7 mm or more and 80 mm or less, preferably 9 mm or more and 30 mm or less.
(8) The contact surface of the striking part that comes into contact with the cushioning material has a curvature of R60 mm or more and R180 mm or less, preferably R90 mm or more and R160 mm or less.
(9) The measured value of the impact load is the maximum value of the impact load that changes over time.
(10) The surface area of the flooring material to be evaluated is 50 ^cm2 or more, preferably 100 cm2 ^or more.
(11) A flooring safety evaluation method using a flooring impact load measurement method, in which a fracture load is calculated based on the user's age, sex, and bone density, and the fracture load and the impact load measured by the flooring impact load measurement method are displayed as indices.

REFERENCE SIGNS LIST 10 Impact absorbing floor material 20 Floor top material 30 Floor underlay material 40 Intermediate layer 50 Design layer 60 Surface protection layer 60 Static compression tester 70 Test stand 80 Sample 90 Compression terminal

Claims (6)

A shock-absorbing flooring material that prevents fractures of the femur caused by the impact of a user falling,
A floor covering made of a hard material;
A floor underlayment material made of a soft material provided below the floor covering material;
The impact absorbing floor material is composed of three layers: the floor top material, the intermediate layer located between the floor underlayment, and
The floor underlayment has a thickness of 4 mm or more and 10 mm or less,
When a static compression test is conducted to measure the test force and displacement, the compressive strain of the floor underlayment is within 0.8 when 5 J of energy is absorbed.
When the static compression test was performed,
An impact absorbing flooring material characterized in that the compression test force at 50% strain is 1200N or more and 1800N or less . The impact absorbing floor material according to claim 1 ,
The intermediate layer has a thickness of 1 mm or more and 3 mm or less,
An impact-absorbing floor material having a bending rigidity per unit width of 0.1 Nm2 or ^more and 10.0 Nm2 or ^less . The impact absorbing floor material according to claim 1 or 2 ,
The floor covering has a thickness of 2 mm or more and 10 mm or less,
The impact absorbing floor material is characterized in that the total thickness of the three layers is 5 mm or more and 20 mm or less. The impact absorbing floor material according to any one of claims 1 to 3 ,
An impact applying object having a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls is dropped from a drop height based on the height of the user's waist, and an impact is applied to a cushioning material made of a material simulating human soft tissue under conditions set so that the standard impact load Fs generated is 6500 N.
This shock-absorbing flooring material is characterized in that when the impact-applying body is dropped from the drop height and an impact is applied to the shock-absorbing flooring material via the cushioning material, the impact load F generated is 2000N or more and 5000N or less. 5. The impact absorbing floor material according to claim 4 , wherein the cushioning material has a dynamic viscoelasticity Tan δ of 0.1 to 0.7 at 25° C. and a measurement frequency of 1 Hz. 6. The shock absorbing floor material according to claim 4 , wherein the cushioning material has a thickness of 7 mm or more and 80 mm or less.

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