JP7336705B2 - shock absorbing flooring - Google Patents

Description

TECHNICAL FIELD The present invention relates to a shock-absorbing flooring material, and is particularly effective in preventing femoral fractures in the event of a fall.

At present, falling fractures in the elderly have become a social problem, and falling fractures account for 10% of the reasons why elderly people require nursing care. Fall fractures account for 20 to 25% of medical accidents. Fracture sites due to falls differ greatly depending on age, and the risk of femoral fracture increases sharply in people in their 60s and beyond. Femoral fracture requires hospitalization for treatment, and the patient cannot walk for a long period of time. Falling fractures account for more than 20% of all accidents at child care facilities such as kindergartens, nursery schools, and certified children's centers.

Therefore, for example, Patent Literatures 1 and 2 below propose floor materials that reduce the risk of bone fractures by absorbing the impact when falling.

Japanese Patent No. 3600726 Japanese Patent No. 5244927

Yasuhiro Nishio et al., Experimental Mechanics, Vol.16, No.4, pp.307-314, 2016 S. N. Robinovitch et al., Journal of Biomechanical Engineering, vol.113, pp.366-374, Nov. 1991 Amy C. Courtney et al., The Journal of Bone and Joint Surgery, vol.77-A, No.3, pp.387-395, Mar. 1995

By the way, in the floor materials described in Patent Documents 1 and 2, etc., the performance is evaluated based on the floor hardness test specified in the Japanese Industrial Standard "JIS A 6519", and the performance is obtained by the test. If the "G value" is 100G or less, it is judged to be "safe".

However, since the floor hardness test described above is a conversion of head injury evaluation, it is difficult to say that the risk of femoral fracture can be properly evaluated. For this reason, it is difficult to say that the above-described conventional flooring materials have sufficiently ensured safety evaluation against femoral fracture, and cannot be said to sufficiently deal with the risk of femoral fracture.

In view of the above, an object of the present invention is to provide a shock-absorbing floor material that can sufficiently cope with the risk of fracture of the femur.

A shock-absorbing flooring material according to the present invention for solving the above-described problems is a shock-absorbing flooring material that suppresses femoral fracture caused by the impact of a fall of a user, and is made of a hard material. and an underfloor material made of a soft material provided below the above floor material, the underfloor material having a foamed structure in which the soft material has an expansion ratio of 3 times or more and 20 times or less, and The dynamic ^{viscoelasticity} Tan δ at a measurement frequency of 1 Hz in the An impact applying body having a weight and shape based on the pressure distribution applied to the body is dropped from a drop height based on the waist height of the user, and impact is applied to the cushioning material made of a material that simulates the soft tissue of the human body. When the impact applying body is dropped from the drop height and impact is applied to the floor material via the cushioning material under conditions set so that the reference impact load Fs generated when the impact is 6500 N, The generated impact load F is 2000 N or more and 5000 N or less, and the amount of displacement of the underfloor material is 0.5 mm or more and 5 mm or less.

The impact-absorbing flooring material according to the present invention can sufficiently cope with the risk of fracture of the femur, and thus reliably reduces the incidence of falling fractures, which are factors such as the need for nursing care of the elderly and medical accidents. be able to.

1 is a schematic structural diagram of a main embodiment of a shock-absorbing flooring material according to the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic structural diagram of a main part of a main embodiment of an impact load measuring device for measuring the impact load of a shock absorbing floor material according to the present invention; FIG. 4 is a schematic structural view of the main part of another embodiment of the impact load measuring device for measuring the impact load of the impact absorbing flooring according to the present invention; FIG. 10 is a schematic structural view of the main part of still another embodiment of the impact load measuring device for measuring the impact load of the impact absorbing flooring according to the present invention; FIG. 10 is a schematic structural view of the main part of still another embodiment of the impact load measuring device for measuring the impact load of the impact absorbing flooring according to the present invention; FIG. 4 is a schematic structural view of another embodiment of the weight of the impact load measuring device for measuring the impact load of the impact absorbing flooring according to the present invention; FIG. 5 is a schematic structural diagram of still another embodiment of the weight of the impact load measuring device for measuring the impact load of the impact absorbing flooring according to the present invention. 4 is a graph showing changes in load over time when impact load is measured.

Embodiments of the shock absorbing floor material according to the present invention will be described based on the drawings, but the present invention is not limited only to the following embodiments described based on the drawings.

[Main embodiment]
Principal embodiments of the impact-absorbing floor material according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, the shock-absorbing flooring material according to the present embodiment is a shock-absorbing flooring material 110 that suppresses fracture of the femur caused by the impact of a fall of the user, and is a flooring material 111 made of a hard material. , an underfloor material 112 made of a soft material provided below the upper floor material 111, a pattern layer 113 laid on the upper surface of the upper floor material 111, and a protective layer 114 laid on the upper surface of the pattern layer 113. are doing.

The floor material 111 includes a wood base material such as plywood, a composite base material obtained by mixing wood flour and plastics, a polyolefin such as polyethylene (PE) or polypropylene (PP), or a resin base material such as vinyl chloride (PVC). It is made of a hard material and constitutes the floor on which the user walks.

The underfloor material 112 is made of a soft material such as a resin such as polyolefin, PVC, ethylene-vinyl acetate copolymer (EVA), polystyrene (PS), polyurethane (PU), etc., and is made of chemical foaming, physical foaming, supercritical foaming, or the like. Depending on the method, it has a foamed structure such as independent foaming or continuous foaming, and constitutes a shock absorbing part that absorbs shock.

The pattern layer 113 is a sheet made of the same material as the flooring material 111, such as polyolefin or PVC, and has a pattern such as wood grain or a geometric pattern on it. It is provided.

The protective layer 114 is made of acrylic coating, transparent PVC, or the like, and protects the surface so as to improve durability such as chemical resistance, scratch resistance, and dent resistance, and is appropriately provided as necessary. It is.

In the impact absorbing flooring material 110, the thickness t1 of the flooring material 111 is 2 mm or more and 20 mm or less (preferably 3 mm or more and 12 mm or less), and the thickness t2 of the underfloor material 112 is 4 mm or more and 10 mm or less (preferably 5 mm or more and 8 mm). below), and the overall thickness t3 is 6 to 25 mm (preferably 7 mm or more and 20 mm or less).

If the thickness t1 of the above floor material 111 is less than 2 mm, local deformation is likely to occur when an impact is applied, making it difficult to disperse the impact to the underfloor material 112. Not only is it difficult to sufficiently express the above, but it is easy to cause the underfloor material 112 to be stuck to the bottom (a phenomenon in which air bubbles, etc. are crushed to a certain point by an impact load and lose their cushioning effect). It is not preferable, and if it exceeds 20 mm, the weight becomes too large, which tends to cause difficulty in workability, which is not preferable.

When the thickness t2 of the underfloor material 112 is less than 4 mm, it becomes difficult to exhibit sufficient impact absorption ability, which is not preferable. .

If the thickness t3 of the shock-absorbing flooring material 110 is less than 6 mm, at least one of the floor material 111 and the underfloor material 112 cannot achieve a sufficient thickness. It is not preferable because it becomes too thick, which tends to cause difficulty in workability.

In the underfloor material 112, the soft material has an expansion ratio of 3 times or more and 20 times or less (preferably 5 times or more and 15 times or less).

If the soft material of the underfloor material 112 has an expansion ratio of less than 3 times, the subfloor sinking is small, the impact absorption capacity is low, and the lightness is also reduced. If it exceeds 20 times, it is not preferable because the sinking becomes large, making it difficult to walk, the structure becomes easy to break, and settling tends to occur with repeated use.

In addition, the underfloor material 112 has a dynamic viscoelasticity Tan δ of 0.1 or more and 0.7 or less (preferably 0.2 or more and 0.5 or less) at a measurement frequency of 1 Hz at 25° C. and a complex elastic modulus E ^* of 0.3 MPa or more and 10 MPa or less (preferably 0.8 MPa or more and 7.0 MPa or less).

When the above Tan δ is less than 0.1, the underfloor material 112 has large elasticity, and it becomes difficult to exhibit sufficient shock absorbing ability. If the above E ^* is less than 0.3 MPa, it becomes easy to deform and sink, making it difficult to walk, which is not preferable. If E ^* exceeds 10 MPa, it becomes difficult to deform, and it becomes difficult to develop sufficient impact absorption capacity, which is not preferable.

In particular, the underfloor material 112 has a bending rigidity (bending stiffness) of the floor top material 111 per unit width of 0.01 Nm ² or more and 5 Nm ² or less, and a complex elastic modulus E ^* of 1 MPa or more and 10 MPa or less. Preferably, the bending rigidity (bending stiffness) of the floor covering 111 per unit width is 0.5 Nm ² or more and 100 Nm ² or less, and the complex elastic modulus E ^* is preferably 0.3 MPa or more and 8 MPa or less.

The value of the bending stiffness (bending stiffness) of the floor covering 111 in a unit width is a value obtained from the product (EI) of the Young's modulus E (bending elasticity) obtained by a three-point bending test and the geometrical moment of inertia I. When the flooring material 111 is made of a composite material in which a plurality of materials with different hardness are laminated, the product of the Young's modulus E (flexural elasticity) and the geometrical moment of inertia I for each layer of each material ( EI) and calculating the sum of these values.

Furthermore, the impact absorbing flooring 110 has a weight and shape based on the pressure distribution applied to the trochanter of the femur when the user falls, and the weight and shape of the impact applying body is based on the waist height of the user. Under conditions set so that the reference impact load Fs generated when the impact is applied to the cushioning material made of a material simulating human soft tissue by dropping it from the drop height is 6500 N, the impact applying body is dropped from the above drop height. The shock load F generated when the floor material is dropped from the height and an impact is applied to the floor material through the cushioning material becomes 2000 N or more and 5000 N or less (preferably 3000 N or more and 4500 N or less), and the displacement of the underfloor material 112 The amount (amount of deformation) D is 0.5 mm or more and 5 mm or less (preferably 1 mm or more and 4 mm or less).

Here, an impact load measuring device for measuring the impact load F and the amount of displacement (deformation) D will be described with reference to FIG.

As shown in FIG. 2 , the impact load measuring device 2 includes a measuring table 5 installed on the floor FL, a weight dropping section 6 arranged on the measuring table 5, and a load measuring section 7. A load cell 8 of a load measuring unit 7 is arranged on the measuring table 5, and an evaluation flooring material 9 made of the same material as the shock absorbing flooring material 110 whose safety against fracture is to be evaluated is placed on the load cell 8. , the cushioning material 10 is placed on the evaluation floor material 9 . The load cell 8 receives the impact load when the weight 11 as the impact imparting body drops, and outputs the information to the impact load calculator 12 .

The weight dropping portion 6 includes a column 13 rising from the measuring table 5, an arm portion 14 extending horizontally perpendicular to the upper portion of the column 13, and a dial or the like that changes the height of the arm portion 14 with respect to the column 13. and a height adjustment unit 15 . An electromagnet 16 is arranged at the lower part of the tip side of the arm 14. When the electromagnet ON/OFF device 17 is turned ON, the weight 11 provided with the accelerometer 18 is attracted to the electromagnet 16, and the electromagnet is turned ON/OFF. When the device 17 is turned off, the weight 11 is separated from the electromagnet 16 together with the accelerometer 18 so that the weight 11 together with the accelerometer 18 falls onto the cushioning material 10 .

The accelerometer 18 outputs the information to the impact energy/displacement calculator 19 . The impact energy/displacement amount calculation device 19 calculates the impact energy SE generated by the collision of the weight 11 based on the information from the accelerometer 18, and the displacement amount (deformation amount) of the underfloor material of the evaluation floor material 9. Calculate D. In this embodiment, the weight drop portion 6, the electromagnet 16, and the electromagnet ON/OFF device 17 correspond to the weight holding drop portion.

In addition, the weight 11 has a hitting portion 11a on the lower surface that contacts the cushioning material 10 and hits, imitating the shape of the trochanter of the femur, and has a radius of curvature R of 60 mm or more and 180 mm or less (preferably 90 mm or more and 160 mm or less). ) and has a spherical shape as a whole.

In addition, the cushioning material 10 is made of an ultra-soft molding urethane resin (for example, "Human skin gel" (trade name) manufactured by Xseal Co., Ltd.) that imitates the soft tissue of the human body, and imitates the soft tissue of the human body around the femur. Asker C hardness (according to Japanese Industrial Standards "JIS K 7312") is more than 0 and less than 16 (preferably 5 or more and 10 or less), Young's modulus is 0.05 MPa or more and 0.8 MPa or less (preferably 0.1 MPa or more and 0.5 MPa below), the dynamic viscoelasticity Tan δ (based on the Non-Patent Document 1) at 25 ° C. at a measurement frequency of 1 Hz is 0.1 or more and 0.7 or less (preferably 0.2 or more and 0.5 or less), and the thickness is It is 7 mm or more and 80 mm or less (preferably 9 mm or more and 30 mm or less).

A method of measuring the impact load F and the amount of displacement (deformation) D using such an impact load measuring device 2 will be described below.

First, the height adjuster 15 is operated so that the arm portion 14 of the weight drop portion 6 of the impact load measuring device 2 reaches the drop height Sh of the weight 11, and the weight 11 (together with the accelerometer 18 weighs Sw). is prepared, and the electromagnet ON/OFF device 17 is turned on to cause the electromagnet 16 arranged on the arm 14 to attract the accelerometer 18 and the weight 11, and the load cell 8 is placed on the measurement table 5, A cushioning material 10 having a thickness of Ka and a hardness of Kb is placed on the load cell 8 .

When the weight 11 and the accelerometer 18 separated from the electromagnet 16 are dropped onto the cushioning material 10 by turning off the electromagnet ON/OFF device 17, the impact load calculation device 12 detects the impact load from the load cell 8. While calculating the standard impact load Fs based on the value, the impact energy/displacement amount calculator 19 calculates the displacement amount (deformation amount) of the cushioning material 10 caused by the impact of the weight 11 based on the information from the accelerometer 18. Along with calculating D1, the impact energy SE is obtained based on the information from the accelerometer 18, the weight Sw, the drop height Sh, and the like.

When the standard impact load Fs is 6500 N and the impact energy SE is 28.4 J, conditions such as the drop height Sh and weight Sw of the weight 11, the thickness Ka and hardness Kb of the cushioning material 10 are adjusted. If the standard impact load Fs is set as it is and the impact energy SE does not become 28.4J, the standard impact load Fs becomes 6500N and the impact energy becomes 28.4J. By appropriately adjusting the above conditions, the reference impact load Fs of the impact load measuring device 2 is set to 6500N and the impact energy SE is set to 28.4J.

The reference impact load Fs should be multiplied by 1.15 as a safety factor because an impact force of 5600 N (muscle relaxation state) is applied to the femur when falling from a standing position (see Non-Patent Document 2). , the value is 6500N. Further, the impact energy SE is a value calculated and determined in advance based on the value of the standard impact load Fs and the conditions (thickness, various physical properties, etc.) of the cushioning material 10, etc. In many cases, it is set to 28.4J. set.

After setting the reference impact load Fs and the impact energy SE of the impact load measuring device 2, the evaluation floor material 9 is placed between the load cell 8 and the cushioning material 10, and then the electromagnet ON/OFF device 17 is turned off again. , the weight 11 separated from the electromagnet 16 is dropped on the cushioning material 10 together with the accelerometer 18, and the impact load F is obtained by the impact load calculation device 12 based on the impact load value from the load cell 8, Based on the information from the accelerometer 18, the impact energy/displacement amount calculation device 19 calculates the amount of displacement (deformation amount) D2 of the cushioning material 10 and the evaluation floor material 9 combined due to the collision of the weight 11, The displacement (deformation amount) D of the underfloor material of the evaluation floor material 9 is calculated by calculating the difference (D2−D1) from the previously obtained displacement amount (deformation amount) D1 of the cushioning material 10 .

If the impact load F thus obtained is less than 2000N, the impact absorption capacity is too strong, making it difficult to walk. It is not preferable because it becomes difficult to sufficiently cope with the risk, and if the displacement amount (deformation amount) D is less than 0.5 mm, it becomes difficult to develop sufficient impact absorption ability, which is not preferable. If it exceeds 5 mm, it is not preferable because it causes difficulty in walking.

Therefore, according to the impact-absorbing flooring 110 according to the present embodiment, it is possible to sufficiently cope with the risk of femoral fracture, so the incidence of falling fractures, which are factors such as the need for nursing care of the elderly and medical accidents, can be reduced. can be reliably reduced.

By the way, the impact-absorbing flooring 110 is required to have different performances depending on the facility in which it is installed. For example, in nursing care facilities for the elderly, ease of walking (feeling of walking) is important because users spend their daily lives there. In recent years, the use of flooring has been increasing, and long sheets of PVC are often used in large-scale projects.

For this reason, in nursing care facilities for the elderly, the flooring material 111 preferably has a thickness t1 of 4 mm or more and 18 mm or less in the case of a wooden base material such as flooring, and the thickness t1 of a resin base material such as PVC. It is preferable in it being 2 mm or more and 8 mm or less. At this time, the underfloor material 112 may have a thickness t2 of 4 mm or more and 10 mm or less.

On the other hand, in medical facilities such as hospitals, operating tables, stretchers, and other heavy items on casters are frequently moved, so caster resistance is required. Static load resistance is required because it is placed in a stationary state. Flooring is rarely used in medical facilities because bacteria and the like may enter the joints, and PVC sheets are the mainstream.

For this reason, in medical facilities, the thickness t1 of the upper floor material 111 is preferably 2 mm or more and 6 mm or less. It is preferable that it is below.

[Other embodiments]
<Impact load measuring device>
In the above-described embodiment, the case where the impact load F is measured using the impact load measuring device 2 as shown in FIG. 2 has been described, but the present invention is not limited to this and other embodiments. Alternatively, for example, it is possible to measure the impact load F using an impact load measuring device as shown in FIGS.

Specifically, in the impact load measuring device 30 shown in FIG. The weight 11, the accelerometer 18, and the load cell 8 are integrated to form an impact applying body, and the weight 11, the accelerometer 18, and the load cell 8 together constitute a weight Sw. When the electromagnet ON/OFF device 17 is turned on, the weight 11 is attracted and held by the electromagnet 16 together with the accelerometer 18 and the load cell 8 .

The weight 11 has a striking portion 11a on the lower surface that is in contact with the cushioning material 10, and has a radius of curvature R of 60 mm or more and 180 mm or less (preferably 90 mm or more and 160 mm), imitating the shape of the trochanter of the femur. below) and has a cylindrical shape as a whole.

In such an impact load measuring device 30, the weight 11 is separated from the electromagnet 16 together with the accelerometer 18 and the load cell 8 by turning off the electromagnet ON/OFF device 17, as in the case of the above-described embodiment. It can be dropped onto the cushioning material 10 .

In addition, the impact load measuring device 31 shown in FIG. The weight dropping portion 6 has a structure in which the arm portion 14 can swing downward around the height adjusting portion 15 . An accelerometer 18 and a load cell 8 are fixed to the tip of the arm 14, and a weight 11 is further fixed. In this embodiment, the weight drop portion 6 corresponds to the weight holding drop portion, the height adjustment portion 15 corresponds to the rotating portion, and the weight 11, the accelerometer 18, the load cell 8, and the arm portion 14 correspond to the impact imparting body. Yes.

In such an impact load measuring device 31, by operating the height adjusting portion 15 of the impact load measuring device 31, the arm portion 14 of the weight dropping portion 6 is adjusted to the dropping height Sh of the weight 11. . By loosening the height adjusting portion 15 and swinging the arm portion 14 downward, the weight 11 can be dropped onto the cushioning material 10 .

In the impact load measuring device 32 shown in FIG. 5, the evaluation floor material 9 is the floor material laid on the existing floor FL. The weight dropping portion 6 of the impact load measuring device 32 also has a structure in which the arm portion 14 can swing downward around the height adjusting portion 15 . An accelerometer 18 and a load cell 8 are fixed to the tip of the arm portion 14, and a weight 11 is further fixed. Incidentally, in this embodiment, the weight 11, the accelerometer 18, the load cell 8, the arm portion 14, and the cushioning material 10 correspond to the impact imparting body.

In such an impact load measuring device 32, by operating the height adjusting portion 15 of the impact load measuring device 31, the arm portion 14 of the weight drop portion 6 is adjusted to the drop height Sh of the weight 11. . By loosening the height adjusting portion 15 and swinging the arm portion 14 downward, the weight 11 can be dropped via the cushioning material 10 toward the evaluation floor material 9 laid on the floor FL. .

<Impact giving body>
Further, in the above-described embodiment, the hitting portion 11a on the lower surface that contacts the cushioning material 10 and hits is designed to have a radius of curvature R of 60 mm or more and 180 mm or less (preferably Although the case where the spherical or cylindrical weight 11 forming a curved surface of 90 mm or more and 160 mm or less is applied, as another embodiment, for example, as shown in FIG. A curvature radius R1 (eg, 175 mm) in one direction (longitudinal direction) and a curvature radius R2 (eg, 65 mm) in the other direction (width direction) orthogonal to the one direction of the striking portion 11a on the lower surface of the ball are set separately. By doing so, it is more preferable to use the weight 11 in which the hitting portion 11a is three-dimensionally approximated to the shape of the trochanter of the femur.

Further, in the above-described embodiment, the case of the impact imparting body in which the striking portion 11a is integrally provided with the weight 11 has been described, but the present invention is not limited to this, and for example, as shown in FIG. The weight 11 is divided into the body part 11b and the striking part 11a for imparting an impact, and a load cell 8, an accelerometer 18, etc. are interposed between the body part 11b and the striking part 11a to form an impact imparting body. is also possible.

<Load measurement part>
Further, in the above-described embodiment, the load cell 8 is used to directly measure the impact load. It is also possible to obtain the impact load based on the acceleration or the like.

<Buffer material>
In the above-described embodiment, the cushioning material 10 made of ultra-soft molding urethane resin is used. It is also possible to apply a cushioning material consisting of body, animal soft tissue or the like.

For example, in G-value measurement for measuring head impact, unfoamed natural rubber is used as a pseudo-scalp, and 15-fold expanded polystyrene foam is used when precision is required. Cell sponge, which is a natural rubber foam, is often used for parts other than the head.

However, these materials have a narrow range of conditions applicable to the above-described measuring method of the impact load measuring device 2, and lack versatility as cushioning materials for measuring impact loads due to falls under various conditions. . That is, the measurement is not stable depending on the conditions because it is specifically affected by the linearity of the deformation rate, stress waves, and the like. Although animal soft tissue behaves in a manner similar to human soft tissue, it is difficult to perform stable measurements because of its large variation as a material.

On the other hand, ultra-soft urethane resin for molding is applicable to the above-described measuring method of the impact load measuring device 2 because it behaves similar to human soft tissue, not to mention that there is no variation as a material. It is very suitable as a cushioning material for measuring the impact load due to a fall under various conditions because it has a wide range of conditions.

EXAMPLES Examples conducted to confirm the effects of the impact absorbing flooring material according to the present invention are described below, but the present invention is not limited to the examples described below.

[Specimen]
Test specimens 1 to 17 of floor materials (surface size: 10,000 mm ² ) consisting of floor materials and underfloor materials shown in Table 1 below were prepared.

In addition, the bending stiffness (bending stiffness) of the flooring material in a unit width is obtained by performing a three-point bending test with a span of 80 mm on a test piece of 100 mm × 30 mm, and obtaining the Young's modulus E (flexural elasticity). The geometrical moment of inertia I was calculated based on the formula (1), and the product (EI) of the Young's modulus E (bending elasticity) and the geometrical moment of inertia I was obtained.

I=(bh ³ )/12 (1)
However, b is 1 (unit width) and h is thickness.

In addition, the dynamic viscoelasticity Tan δ and the complex elastic modulus E ^* of the underfloor material were measured using a dynamic viscoelasticity measuring device "DMA8000" (model number) manufactured by PerkinElmer Co., Ltd. at a measurement frequency of 1 Hz at 25 ° C. Measured by compression mode.

[contents of the test]
For the test pieces 1 to 17, the impact load F, the amount of displacement (deformation) D, and the presence/absence of bottoming were determined using basically the impact load measuring device 2 described above. However, in the impact load measuring device 2, the weight 11 is divided into a main body portion 11b having a weight and a striking portion 11a for imparting an impact as shown in FIG. An impact applying body was constructed by interposing an accelerometer 18 between the portion 11a and the portion 11a.

<Equipment specifications>
・Load cell/"TCLU-5A" manufactured by Tokyo Sokki Kenkyusho Co., Ltd. (model number)
・ Accelerometer / Showa Sokki Co., Ltd. digital shock / vibration accelerometer "1340B" (model number)
・Measuring table/Surface plate Size: 750mm x 1000mm x 125mm Weight: 185kg
・Weight body/material: stainless steel ・Weight striking part/material: machined stainless steel Curvature radius R: 100mm
・Impacting body / weight Sw: 5.85 kg (including accelerometer)
・ Cushioning material / “Human skin gel” (trade name) manufactured by Xseal Co., Ltd.
Thickness: 20 mm Asker C hardness: 7 Young's modulus: 0.22 MPa
Dynamic viscoelasticity Tan δ: 0.24 (25°C, measurement frequency 1 Hz)

<Test method>
As described in the above embodiment, the weight 11 is dropped (dropping height Sh: 50 cm), and based on the information from the load cell 8, the impact loads Fs, F and the presence or absence of bottoming are obtained, and the acceleration Impact energy SE and displacement amounts (deformation amounts) D1, D2, and D were obtained based on the information from the meter.

The presence or absence of bottoming was determined by the presence or absence of an inflection point until the peak (impact load F) was reached in the waveform of the load (graph showing changes in load over time). That is, as shown in FIG. 8A, if no inflection point occurs before reaching peak Pm, it is determined that there is no bottoming, and as shown in FIG. When Pi was generated, it was determined that there was bottoming.

In addition, the impact load F was classified into the ranks shown in Table 2 below based on the description in Non-Patent Document 3, and was determined.

[Test results]
The results of the tests described above are shown in Table 3 below.

As can be seen from the results in Table 3 above, in test specimens 8, 9, 12, and 15, the dynamic viscoelasticity Tan δ and the complex elastic modulus E ^* of the underfloor material were out of range, so impact load F exceeded 5000N, and the evaluation was "x". In addition, in test specimens 13 and 14, since the expansion ratio of the underfloor material was out of the range, the impact load F exceeded 5000 N, and the evaluation was "x". In particular, since the expansion ratio of the underfloor material of the test sample 13 was less than 3 times, the amount of displacement (variation) D of the underfloor material was less than 0.5 mm.

In addition, the thickness t2 of the underfloor material of the test body 10 is relatively thin at 3 mm, and the impact absorption capacity cannot be fully expressed, the impact load F exceeds 5000 N, and the evaluation is "x". In 11, since the thickness t2 of the underfloor material is relatively thick at 12 mm, the impact absorption capacity is high, and the impact load F is less than 2110 N, but the displacement amount D of the underfloor material exceeds 5 mm, and walking is difficult. The evaluation was "x" because there was a problem with the performance.

On the other hand, in test specimens 1 to 7, the dynamic viscoelasticity Tan δ and complex elastic modulus E ^* of the underfloor material and the expansion ratio are within the range, so the impact load F is all 5000 N or less. , Displacement (displacement) D is 5 mm or less, and there is no problem in walking, and bottoming does not occur.

From the above, it was confirmed that the impact-absorbing flooring material according to the present invention can sufficiently cope with the risk of fracture of the femur.

Since the impact-absorbing flooring material according to the present invention can sufficiently cope with the risk of femoral fracture, it can be used not only in nursing care facilities for the elderly, but also in medical facilities such as hospitals, as well as kindergartens, nursery schools, and certified children. It can be applied to floor surfaces of various facilities such as kindergartens and other facilities related to child care, and can be industrially extremely useful.

2, 30 to 32 impact load measuring device 5 measuring table 6 weight dropping part 7 load measuring part 8 load cell 9 evaluation floor material 10 cushioning material 11 weight 11a striking part 11b body part 12 impact load calculating device 13 support 14 arm part 15 height Adjustment Unit 16 Electromagnet 17 Electromagnet ON/OFF Device 18 Accelerometer 19 Impact Energy/Displacement Calculator 110 Shock Absorbing Flooring Material 111 Flooring Material 112 Underfloor Material 113 Pattern Layer 114 Protective Layer

Claims (9)

A shock-absorbing flooring material that suppresses fracture of the femur caused by the impact of a fall of the user,
a flooring material made of a hard material;
an underfloor material made of a soft material provided below the above floor material,
In the underfloor material, the soft material has a foamed structure with an expansion ratio of 3 to 20 times, and a dynamic viscoelasticity Tan δ at a measurement frequency of 1 Hz at 25 ° C. is 0.1 to 0.7 and complex. Elastic modulus E ^* is 0.3 MPa or more and 10 MPa or less,
dropping an impact applying body having a weight and a shape based on the pressure distribution applied to the trochanter of the femur when the user falls from a drop height based on the waist height of the user, The impact applying body is dropped from the drop height under conditions set so that the standard impact load Fs generated when an impact is applied to a cushioning material made of a material that simulates human soft tissue is 6500 N, and the cushioning material is applied. An impact load F generated when an impact is applied to the floor material through the material is 2000 N or more and 5000 N or less, and a displacement amount of the underfloor material is 0.5 mm or more and 5 mm or less. shock-absorbing flooring. In the impact-absorbing flooring material according to claim 1,
A shock-absorbing flooring material, wherein the underfloor material has a thickness of 4 mm or more and 10 mm or less. In the impact-absorbing flooring material according to claim 1 or claim 2,
A shock-absorbing flooring material characterized in that the bending rigidity value of the flooring material per unit width is 0.01 Nm ² or more and 5 Nm ² or less, and the complex elastic modulus E ^* of the underfloor material is 1 MPa or more and 10 MPa or less. . In the impact-absorbing flooring material according to claim 1 or claim 2,
The bending rigidity value of the floor material per unit width is 0.5 Nm ² or more and 100 Nm ² or less, and the complex elastic modulus E ^* of the underfloor material is 0.3 MPa or more and 8 MPa or less. flooring. In the impact-absorbing flooring material according to any one of claims 1 to 4,
The impact absorbing flooring material, wherein the impact imparting body has a striking part that strikes the cushioning material in contact with the cushioning material, and the striking part has a curved surface with a curvature radius R of 60 mm or more and 180 mm or less. In the impact-absorbing flooring material according to any one of claims 1 to 5,
A shock-absorbing flooring material, wherein the cushioning material has an Asker C hardness of more than 0 and less than 16. In the impact-absorbing flooring material according to any one of claims 1 to 6,
A shock-absorbing flooring material, wherein the cushioning material has a dynamic viscoelasticity Tan δ of 0.1 or more and 0.7 or less at a measurement frequency of 1 Hz at 25°C. In the impact-absorbing flooring material according to any one of claims 1 to 7,
A shock-absorbing flooring material, wherein the cushioning material has a thickness of 7 mm or more and 80 mm or less. In the impact-absorbing flooring material according to any one of claims 1 to 8,
A shock-absorbing flooring material, wherein the cushioning material is made of ultra-soft urethane resin for modeling.

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