JP7580189B2 - Floor cushioning and floor construction materials - Google Patents

Description

The present invention relates to floor cushioning materials and floor components that are useful for absorbing shock, and in particular to floor cushioning materials and floor components that can absorb shock during a fall collision.

Floor constituent materials are required to be thin, lightweight, and have shock mitigating properties. For example, Patent Document 1 (JP 2016-216928 A) discloses a shock mitigating floor constituent material comprising a buffer layer arranged in the bottommost layer, a plate material arranged adjacent to the upper side of the buffer layer, and a buffer layer arranged in the topmost layer on the opposite side of the plate material from the buffer layer, wherein the buffer layer arranged in the topmost layer has a compressive modulus of elasticity of 100 to 2500 kPa and a thickness of 0.5 to 4 mm, the buffer layer arranged in the bottommost layer has a compressive modulus of elasticity of 10 to 500 kPa, and the plate material has a product of bending modulus and thickness of 1.0 x ¹⁰⁴ or more.

In Patent Document 1, the product of the compressive elastic modulus of the buffer layer placed above the plate and the buffer layer placed below the plate, and the bending elastic modulus and thickness of the plate are adjusted within a specific range to realize a thin shock-absorbing floor component with excellent shock-absorbing properties.

For example, the Architectural Institute of Japan specifies that the recommended hardness value for floors in kindergartens, hospitals, elderly care facilities, athletic facilities, and other locations where consideration for fall impacts is desired is 100 G or less, and Patent Document 1 satisfies this recommended value.

JP 2016-216928 A

However, in recent years, further improvements have been required for shock-absorbing tatami flooring in the event of a fall collision, and the recommended hardness value for shock-absorbing tatami flooring specified in JIS A 5917 (2018) is 50 G or less. On the other hand, with simply soft cushioning materials such as those used in gymnastics, it is necessary to increase the thickness to prevent the base from touching the ground, which creates the problem of a poor walking feel.

Therefore, an object of the present invention is to provide a floor cushioning material that can further improve the shock mitigation properties against the impact during a fall collision.
Another object of the present invention is to provide a floor constituent material which not only achieves the above-mentioned shock absorbing properties but also provides a comfortable stepping and sitting experience which is neither too hard nor too soft.

As a result of intensive research by the inventors of the present invention to achieve the above object, they have discovered that a cushioning material that combines a first buffer layer whose compressive elastic modulus when compressed from 10% to 20% is in a specific small range and a second buffer layer whose compressive elastic modulus when compressed from 2.5% to 5.0% is in a specific large range, and that the second buffer layer is disposed below the first buffer layer, can surprisingly achieve shock mitigation that exceeds that of Patent Document 1, although the reason is unclear. They have also discovered that a floor component equipped with such a floor cushioning material can combine not only good shock mitigation, but also good comfort when stepped on and sat on, which led to the completion of the present invention.

That is, the present invention can be configured in the following manner.
[Aspect 1]
A floor cushioning material comprising at least a first cushioning layer and a second cushioning layer disposed below the first cushioning layer,
the compressive elastic modulus when the first buffer layer is compressed from 10% to 20% is 0.01 to 29 kPa (preferably 0.1 to 20 kPa, more preferably 0.5 to 15 kPa);
The floor cushioning material has a compressive elastic modulus of 30 to 12,000 kPa (preferably 50 to 11,000 kPa, more preferably 80 to 10,500 kPa) when the second cushioning layer is compressed from 2.5% to 5.0%.
[Aspect 2]
A floor cushioning material according to aspect 1, wherein the compressive elastic modulus when the second buffer layer is compressed from 2.5% to 5.0% is 50 kPa or more higher (preferably 80 kPa or more higher) than the compressive elastic modulus when the first buffer layer is compressed from 10% to 20%.
[Aspect 3]
A floor cushioning material according to aspect 1 or 2, wherein the second cushioning layer has a bending strength of 0.2 N/mm ² or more (preferably 0.3 to 3 N/mm ² ).
[Aspect 4]
A floor cushioning material according to any one of aspects 1 to 3, wherein the thickness of the first buffer layer is 20 mm or less (preferably 1 to 18 mm, more preferably 3 to 15 mm), and the thickness of the second buffer layer is 0.8 times or more (preferably 0.8 to 6 times, more preferably 0.8 to 5 times) the thickness of the first buffer layer.
[Aspect 5]
A floor cushioning material according to any one of Aspects 1 to 4, wherein the first cushioning layer is a nonwoven fiber structure having an apparent density of 30 to 70 kg/m ³ (preferably 35 to 65 kg/m ³ , more preferably 40 to 60 kg/m ³ ).
[Aspect 6]
A floor cushioning material according to any one of aspects 1 to 5, wherein the first cushioning layer and the second cushioning layer can be integrated together by a connecting means.
[Aspect 7]
The floor cushioning material according to any one of aspects 1 to 6, wherein the impact acceleration G value during a fall collision measured in accordance with JIS A 5917 (2018) through a 5.5 mm thick Chinese plywood is 45 G or less (preferably 42 G or less, more preferably 39 G or less). The floor cushioning material.
[Aspect 8]
A floor cushioning material according to any one of aspects 1 to 7, wherein the first cushioning layer is a nonwoven fiber structure in which fibers are fixed to each other by fusion of the moist heat adhesive fiber.
[Aspect 9]
A floor cushioning material according to any one of aspects 1 to 8, wherein the second cushioning layer is at least one selected from the group consisting of a natural fiber molded board, a synthetic fiber molded board, an inorganic fiber molded board, and a foamed plastic board. A floor cushioning material.
[Aspect 10]
A floor construction material comprising at least the floor cushioning material according to any one of aspects 1 to 9 and a board material, and a first cushioning layer is disposed on the underside of the board material.
[Aspect 11]
A flooring component according to aspect 10, wherein the hardness during daily operation measured according to JIS A 5917 (2018) is 0.6 to 2.0 (preferably 0.6 to 1.5, more preferably 0.7 to 1.4, and even more preferably 0.8 to 1.3).
[Aspect 12]
A floor construction according to aspect 10 or 11, wherein the flexural modulus of the plank material is 500 to 4000 MPa (preferably 550 to 3000 MPa).
[Aspect 13]
A floor constructing material according to any one of aspects 10 to 12, having a thickness of 100 mm or less (preferably a thickness of 80 mm or less, more preferably a thickness of 65 mm or less), and an impact acceleration G value measured in accordance with JIS A 6519 of 45 G or less (preferably 42 G or less, more preferably 39 G or less).
Aspect 14
A floor construction according to any one of aspects 10 to 13, wherein the floor construction is a tatami floor, a wood floor, a polymer sheet floor, a ceramic floor, or a carpet floor.
In this specification, the term "underside" includes both a case where the part is disposed under the other in a state of direct contact, and a case where the part is disposed under the other without direct contact.

The floor cushioning material of the present invention combines a first cushioning layer which has a moderately small compressive elastic modulus when further compressed from a state already compressed to a certain extent, with a second cushioning layer disposed below the first cushioning layer which has a moderately large compressive elastic modulus at the start of compression, thereby providing floor components equipped with the floor cushioning material with good shock mitigation properties against impacts during a fall collision.
Furthermore, by providing the floor cushioning material of the present invention, it is possible to obtain a floor component that not only achieves shock mitigation, but also provides a comfortable stepping and sitting experience that is neither too hard nor too soft.

The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation, and should not be used to define the scope of the present invention, which is defined by the appended claims.
FIG. 1 is a schematic cross-sectional view for explaining a laminate (or floor component) of a floor cushioning material and a plate material, which is one embodiment of the present invention. 1 is a schematic cross-sectional view showing a floor cushioning material according to one embodiment of the present invention. FIG. 1 is a schematic cross-sectional view showing a floor component according to one embodiment of the present invention.

The floor cushioning material of the present invention is composed of at least a first cushioning layer and a second cushioning layer disposed below the first cushioning layer. The floor construction material of the present invention is composed of at least a board material and the floor cushioning material, and the first cushioning layer is disposed below the board material.

One embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view for explaining a laminate (or floor component) of a floor cushioning material and a plate material, which is one embodiment of the present invention. In Figure 1, the floor cushioning material 10 is composed of a first buffer layer 2 and a second buffer layer 3 disposed below the first buffer layer 2. In addition, a plate material 1 is disposed above the floor cushioning material 10, i.e., on the opposite side of the second buffer layer 3 via the first buffer layer 2, to form a floor component 20.

For example, when pressure is applied locally to plate material 1 due to an impact such as a fall, plate material 1, which is made of a material that is difficult to deform, transmits the received pressure over a large area to first buffer layer 2. Then, first buffer layer 2 transmits part of the pressure from the plate material to second buffer layer 3 while mitigating the received pressure to some extent.

The second buffer layer 3 has a greater compressive elastic modulus than the first buffer layer 2, so bottoming out can be prevented when an impact is applied to the second buffer layer 3, and as a result, the acceleration G value at the time of impact can be reduced. Furthermore, although the reason is unclear, by placing the second buffer layer 3 below the first buffer layer 2, the acceleration G value at the time of impact can be significantly reduced compared to when the first buffer layer 2 and the second buffer layer 3 are each used alone. With a floor component including the floor cushioning material of the present invention, the acceleration G value at the time of impact can be reduced, thereby improving safety during a fall collision.

In addition, between the plate material 1, the first buffer layer 2, and the second buffer layer 3, there may be other layers (e.g., sheet-like or cut-like materials such as waterproof sheets, dehumidifying sheets, mold-proof sheets, insect-proof sheets, and slip-prevention sheets) as appropriate, as long as they do not inhibit the effects of the present invention.

The components consisting of the plate material 1, the first buffer layer 2, and the second buffer layer 3 may or may not be fixed to each other by a connecting means. If they are fixed, they may be detachable.

For example, in FIG. 1, (i) the plate material 1 and the first buffer layer 2 may be integrated and placed on the second buffer layer 3 without being fixed, (ii) the first buffer layer 2 and the second buffer layer 3 may be integrated and the plate material 1 may be placed on the first buffer layer 2 without being fixed, or (iii) the plate material 1, the first buffer layer 2 and the second buffer layer 3 may be integrated. From the viewpoint of handling, the above (iii) is preferable. In addition, the plate material 1, the first buffer layer 2, and the second buffer layer 3 may have the same size or different sizes. For example, the first buffer layer 2 and the second buffer layer 3, which have small areas, may be placed so as to cover them with the plate material 1, which has a large area, or the plate material 1, which has a small area, may be placed on the first buffer layer 2 and the second buffer layer 3, which have large areas. In addition, the areas of the first buffer layer 2 and the second buffer layer 3 may also be different.

The connecting means may be adhesive or glue, but it is preferable to use hook-and-loop fasteners so that they can be attached and detached. Alternatively, sewing, a method commonly used to manufacture tatami mats, may be used. When the various parts are joined together with detachable connecting means, not only can the various components be manufactured and stored separately, but they can also be joined together as needed before use, improving ease of handling.

Figure 2 shows a schematic cross-sectional view of a floor cushioning material according to one embodiment of the present invention. Figure 2 shows a floor cushioning material 10, which is the portion of Figure 1 excluding the plate material 1, and the floor cushioning material 10 is composed of a first cushioning layer 2 and a second cushioning layer 3 disposed below it. Such a floor cushioning material 10 can be used as a core material or base material for floor components used in painted floors, floor coverings, and floor coverings, in combination with various finishing materials.

Figure 3 shows a schematic cross-sectional view of a floor construction material according to one embodiment of the present invention. The floor construction material 30 includes a floor cushioning material 10 composed of a first cushioning layer 2 and a second cushioning layer 3 disposed below it, with a board material 1 disposed on the floor cushioning material 10, a cushioning material 5 disposed on the board material 1, and a surface decorative material 4 disposed on the cushioning material 5.

In addition, between the surface decorative material 4, the cushioning material 5, the plate material 1, the first buffer layer 2, and the second buffer layer 3, there may be other layers (e.g., sheet-like or cut-like materials such as waterproof sheets, dehumidifying sheets, mold-proof sheets, insect-proof sheets, and slip-prevention sheets) as appropriate, as long as they do not inhibit the effects of the present invention.

The components consisting of the surface decorative material 4, the cushioning material 5, the plate material 1, the first buffer layer 2, and the second buffer layer 3 may or may not be fixed to each other by a connecting means. If they are fixed, they may be detachable.

For example, in FIG. 3, similarly to FIG. 1, each component may be simply placed on top of the other without being fixed to each other, or may be fixed to each other by a connecting means. For example, the cushioning material 5 and the plate material 1 may be integrated and placed on the floor cushioning material 10, or the surface decorative material 4, the cushioning material 5 and the plate material 1 may be integrated and placed on the floor cushioning material 10. Alternatively, the surface decorative material 4, the cushioning material 5, the plate material 1 and the first buffer layer 2 may be integrated and placed on the second buffer layer 3, or the surface decorative material 4 and the cushioning material 5 may be integrated and placed on the plate material 1.

From the viewpoint of ease of handling, it is preferable that the surface decorative material 4, the cushioning material 5, the board material 1, the first buffer layer 2, and the second buffer layer 3 in the floor construction material 30 are integrated together, for example, by a detachable connecting means as required.

The floor cushioning material and floor component of the present invention are not limited to the embodiment shown in Figures 1 to 3 and may have various configurations, but the following describes each of the components that are typically used.

(First Buffer Layer)
The first buffer layer may have a compressive elastic modulus of 0.01 to 29 kPa, preferably 0.1 to 20 kPa, and more preferably 0.5 to 15 kPa, when compressed from 10% to 20%. Note that the compressive elastic modulus when compressed from 10% to 20% refers to a numerical value measured as the elastic modulus when a test specimen cut into a disk shape having a diameter of 29 mm is compressed from a strain of 10% to 20% by a pressure plate at a test speed of 10 mm/min in accordance with JIS K 7181.

For the first buffer layer, by measuring the compressive elastic modulus when it is further compressed from a state that has already been compressed to a certain extent, rather than the compressive elastic modulus at the beginning of compression, it is possible to evaluate the shock mitigation properties against a large impact that occurs during a fall collision.

The thickness of the first buffer layer may be, for example, 20 mm or less, preferably 1 to 18 mm, and more preferably 3 to 15 mm. Here, the thickness may be, for example, a thickness measured in accordance with JIS L 1913 "General short fiber nonwoven fabric test method."

The apparent density of the first buffer layer may be, for example, 30 to 70 kg/ ^m3 , preferably 35 to 65 kg/ ^m3 , and more preferably 40 to 60 kg/ ^m3 . Here, the apparent density is a density based on the volume calculated from the external dimensions of the foam, and may be measured by a measurement method commonly used depending on the material. For example, when the first buffer layer is a nonwoven fiber structure, the density may be calculated from the thickness measured in accordance with JIS L 1913 "Testing methods for general staple fiber nonwoven fabrics" and the basis weight measured in accordance with JIS L 1913 "Testing methods for general staple fiber nonwoven fabrics".

As long as the first buffer layer exhibits these properties, various materials can be used, such as plastic foams (e.g., polystyrene foam, polyurethane foam, polyolefin foam, etc.) and fiber structures (e.g., nonwoven fiber structures, felt). These materials may be used alone or in combination of two or more. Among these, fiber structures are preferably used, not only because they exhibit a predetermined compressive elastic modulus even with a relatively large strain, but also because they have excellent durability against repeated impacts.

Examples of fiber structures include physically entangled fiber structures such as felt, nonwoven fiber structures obtained by mechanically compressing nonwoven fabric (e.g., needle punching), nonwoven fiber structures obtained by partially heat-pressure fusing nonwoven fabric (e.g., heat embossing), and nonwoven fiber structures in which fibers are fixed to each other by adhesion or fusing with a binder component. The fibers constituting the fiber structures may be natural or synthetic fibers, and examples of synthetic fibers include polyolefin fibers, (meth)acrylic fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polystyrene fibers, polyester fibers, polyamide fibers, polycarbonate fibers, and polyurethane fibers. Of these fibers, polyester fibers, polyamide fibers, or composite fibers containing these fibers are commonly used.

The average fineness of the main fibers and/or binder fibers constituting the nonwoven fiber structure can be set appropriately as long as it satisfies the compressive elastic modulus required for the first buffer layer. For example, the average fineness may be in the range of 0.1 to 30 dtex, and is preferably in the range of 0.5 to 20 dtex.

In the present invention, among nonwoven fiber structures, fiber structures in which fibers are fixed to each other by fusion of a binder component (particularly binder fibers composed of thermally adhesive fibers composed of thermally adhesive resins such as polyester-based, polyamide-based, polyolefin-based, and polyvinyl alcohol-based) are preferred, and from the viewpoint of achieving both impact relaxation and strength, structures containing moist heat adhesive fibers and in which fibers are fixed to each other by fusion of the moist heat adhesive fibers (nonwoven fiber structures containing moist heat adhesive fibers) are particularly preferred. A structure containing moist heat adhesive fibers and in which fibers are fixed to each other by fusion of the moist heat adhesive fibers (hereinafter sometimes referred to as a "nonwoven fiber structure containing moist heat adhesive fibers") can be obtained, for example, by spraying high-temperature steam. The internal structure of the nonwoven fiber structure obtained by spraying high-temperature steam is uniformly bonded in the thickness direction, so that high strength can be ensured while maintaining the fiber structure.

The heat-and-moisture adhesive fiber is configured to contain at least a heat-and-moisture adhesive resin capable of exhibiting an adhesive function when high-temperature steam is sprayed. Specific examples of the heat-and-moisture adhesive resin include thermoplastic resins that are softened by hot water (e.g., 80 to 120°C, particularly 95 to 100°C) and can be self-adhesive or adhere to other fibers, such as vinyl alcohol polymers such as ethylene-vinyl alcohol copolymers, polylactic acid resins such as polylactic acid, and (meth)acrylic copolymers containing (meth)acrylamide units. Furthermore, elastomers capable of exhibiting an adhesive function when high-temperature steam is sprayed (e.g., polyolefin elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, polystyrene elastomers, etc.) may be used. These heat-and-moisture adhesive resins may be used alone or in combination of two or more. Among these, vinyl alcohol polymers containing α _{-C 2-10 olefin} units such as ethylene and propylene, particularly ethylene-vinyl alcohol copolymers, are preferred.

In the case of composite fibers, the heat-sensitive adhesive resins may be combined with each other, or may be combined with a non-heat-sensitive adhesive resin. Examples of the non-heat-sensitive adhesive resin include water-insoluble or hydrophobic resins, such as polyolefin resins, (meth)acrylic resins, polyvinyl chloride resins, polystyrene resins, polyester resins, polyamide resins, polycarbonate resins, polyurethane resins, and thermoplastic elastomers. These non-heat-sensitive adhesive resins may be used alone or in combination of two or more.

Among these non-moisture heat adhesive resins, from the standpoint of heat resistance and dimensional stability, resins with a higher melting point than the moisture heat adhesive resins (particularly ethylene-vinyl alcohol copolymers) are preferred, such as polypropylene-based resins, polyester-based resins, and polyamide-based resins, with polyester-based resins and polyamide-based resins being particularly preferred because of their excellent balance of heat resistance, fiber formability, etc. Examples of polyester resins include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, phthalic acid, α,β-(4-carbophenoxy)ethane, 4,4-dicarboxydiphenyl, and 5-sodium sulfoisophthalic acid, aliphatic dicarboxylic acids such as azelaic acid, adipic acid, and sebacic acid, and esters thereof, and fiber-forming polyester resins made of diols such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, polyethylene glycol, and polytetramethylene glycol, and it is preferable that 80 mol % or more of the constituent units are ethylene terephthalate units. Examples of polyamide resins include aliphatic polyamides mainly composed of nylon 6, nylon 66, and nylon 12, and polyamides containing a small amount of a third component may also be used.

The cross-sectional shape of the heat-and-moisture adhesive fiber (cross-sectional shape perpendicular to the length of the fiber) is not limited to a typical solid cross-sectional shape such as a round cross-section or an irregular cross-section (flat, elliptical, polygonal, etc.), but may be a hollow cross-sectional shape. The heat-and-moisture adhesive fiber may be a composite fiber composed of multiple resins including at least a heat-and-moisture adhesive resin. The composite fiber may have the heat-and-moisture adhesive resin on at least a part of the fiber surface, but from the viewpoint of adhesion, it is preferable for the fiber surface to have the heat-and-moisture adhesive resin continuous in the length direction.

Examples of cross-sectional structures of composite fibers in which the surface is occupied by the heat-and-moisture adhesive resin include core-sheath type, sea-island type, side-by-side type, multi-layer lamination type, radial lamination type, and random composite type. Of these cross-sectional structures, a core-sheath type structure in which the entire surface of the fiber is covered with the heat-and-moisture adhesive resin (i.e., a core-sheath type structure in which the sheath portion is composed of the heat-and-moisture adhesive resin) is preferred because it has high adhesiveness. The core-sheath type structure may be a fiber in which the surface of a fiber composed of another fiber-forming polymer is coated with a heat-and-moisture adhesive resin.

The nonwoven fiber structure may further contain non-heat-adhesive fibers in addition to the heat-adhesive fibers. Examples of non-heat-adhesive fibers include fibers composed of the non-heat-adhesive resin constituting the composite fiber, as well as cellulosic fibers (e.g., rayon fibers, acetate fibers, etc.). These non-heat-adhesive fibers can be used alone or in combination of two or more. These non-heat-adhesive fibers can be used alone or in combination of two or more. These non-heat-adhesive fibers can be selected according to the desired characteristics, and when combined with semi-synthetic fibers such as rayon, a fiber structure with relatively high density and high mechanical properties can be obtained.

The ratio (mass ratio) of the moist heat adhesive fibers to the non-moisture heat adhesive fibers is not particularly limited, but it is preferable that the moist heat adhesive fibers/non-moisture heat adhesive fibers be 100/0 to 20/80, and more preferably 100/0 to 50/50.

A nonwoven fiber structure containing such heat-and-moisture adhesive fibers is marketed by Kuraray Co., Ltd. under the name "Felibendy."

(Second Buffer Layer)
The second buffer layer may have a compressive elastic modulus of 30 to 12,000 kPa, preferably 50 to 11,000 kPa, and more preferably 80 to 10,500 kPa when compressed from 2.5% to 5.0%. Note that the compressive elastic modulus when compressed from 2.5% to 5.0% refers to a numerical value measured as the elastic modulus when a test specimen cut into a disk shape having a diameter of 29 mm is compressed from a strain of 2.5% to 5.0% by a pressure plate at a test speed of 10 mm/min in accordance with JIS K 7181.

The second buffer layer's responsiveness to the strain received from the first buffer layer can be accurately evaluated by measuring the compressive modulus mainly at the beginning of compression. By disposing a second buffer layer with a slightly harder compressive modulus under a first buffer layer with a specific softer compressive modulus, it is surprisingly possible to reduce the impact acceleration G value in the laminated state of the first buffer layer and the second buffer layer more than conventionally. This is an unexpected effect that could not be predicted, considering that the impact acceleration G values of the first buffer layer and the second buffer layer are about the same as conventional impact acceleration G values.

Preferably, the compressive modulus of elasticity when the second buffer layer is compressed from 2.5% to 5.0% may be 50 kPa or more higher than the compressive modulus of elasticity when the first buffer layer is compressed from 10% to 20%, and more preferably 80 kPa or more higher.

The thickness of the second buffer layer may be, for example, 5 to 50 mm, preferably 7 to 45 mm, and more preferably 9 to 40 mm. Here, the thickness may be measured by an appropriate method depending on the material, but for example, in the case of a nonwoven fiber structure, the thickness may be measured in accordance with JIS L 1913 "General short fiber nonwoven fabric test method."

The thickness of the second buffer layer may be, for example, 0.8 times or more, preferably 0.8 to 6 times, and more preferably 0.8 to 5 times, the thickness of the first buffer layer.

From the viewpoint of receiving the pressure from the first buffer layer, the bending strength of the second buffer layer may be, for example, 0.2 N/mm2 or ^more , and preferably 0.3 to 3 N/ ^mm2 . Here, when the bending strength differs depending on the direction, the bending strength in the direction in which the bending strength is greater is taken as the bending strength. The bending strength is a value measured by the method described in the examples described later.

As long as the second buffer layer exhibits such properties, various materials can be used, such as a molded board of natural fibers (preferably vegetable fibers), a molded board of synthetic fibers, a molded board of inorganic fibers, and a foamed plastic board. Examples of molded boards of natural fibers and synthetic fibers include medium density fiberboard (MDF), insulation fiberboard (particularly tatami board as specified in JIS A 5905), palm board, kenaf board, and rice straw tatami mat. Examples of molded boards of inorganic fibers include carbon fiber board and glass fiber board. Examples of foamed plastic boards include foamed rigid urethane board, foamed polystyrene board (particularly extrusion foamed polystyrene board as specified in JIS A 9511), foamed polyolefin board, and foamed phenolic resin board. These materials may be used alone or in combination of two or more.

As the second buffer layer, tatami board as specified in JIS A 5905 can be preferably used. If necessary, extruded polystyrene foam as specified in JIS A 9511 or equivalent or higher can be used under the second buffer layer (e.g., tatami board).

(Board material)
As for the plate material, various materials can be used as long as they are, unlike the buffer layer, materials that do not undergo local deformation in response to a localized impact, such as various natural boards, plywood, plant fiber molded boards, plastic boards, metal boards, ceramic boards, and composite boards.

From the viewpoint of suppressing local deformation of the plate material, the flexural modulus of the plate material may be, for example, 500 to 4000 MPa, and preferably 550 to 3000 MPa. The flexural modulus is a value measured according to the provisions of JIS K 7171 at a test speed of 10 m/min, varying from 0.25% to 0.5%. If the flexural modulus differs depending on the direction, the higher flexural modulus is used.

The thickness of the plate material is not particularly limited as long as it is possible to suppress local deformation, but may be, for example, 3 to 15 mm, and preferably 4 to 13 mm. In addition, cushioning material or surface decorative material may be disposed on the plate material as necessary.

The cushioning material is thinner than the first buffer layer from the viewpoint of improving the cushioning properties of the board while transmitting impact to the board, i.e., mitigating the impact and improving comfort, and the thickness of the cushioning material is preferably, for example, about 1 to 5 mm, which provides adequate cushioning properties. The thickness of the cushioning material may be thicker, the same as, or thinner than the thickness of the board, but is preferably thin.

The material constituting the cushioning material is not particularly limited as long as it is capable of exhibiting cushioning properties, and may be, for example, the material of the first buffer layer, a rubber or elastomer molded body, a fiber structure (a structure composed of woven fabric, knitted fabric, nonwoven fabric, etc.), etc.

Surface decorative materials can be selected from materials used in floor construction materials according to the purpose, and examples include various tatami mat surfaces (rush tatami mat surfaces, resin tatami mat surfaces, washi paper tatami mat surfaces), soft floors, fabrics (woven fiber fabrics), cork boards, soft or hard plastic sheets, etc.

As for the finishing material, board materials and surface decorative materials may be used as they are, or when applying to the surfaces of multiple floor components (or floor cushioning materials) together, various materials used as finishing materials may be used. Examples of finishing materials include synthetic paints and natural paints for painted floors, polymer sheet materials, wood board materials, wood block materials, plastic tile materials, ceramic tile materials, natural stone materials, artificial stone materials, laminated floor materials, and carpet materials for floor coverings.

(Floor cushioning materials and floor components)
Since the floor cushioning material of the present invention has excellent impact resistance even when thin, it may have a thickness of, for example, 80 mm or less, preferably 60 mm or less, more preferably 45 mm or less. The lower limit of the thickness is not limited as long as it can exhibit impact resistance, but may be, for example, about 20 mm.

The floor component of the present invention is composed of at least a floor cushioning material and a plate material, and a first cushioning layer is disposed on the underside of the plate material. Since the plate material has excellent impact resistance even when it is thin, the thickness may be, for example, 100 mm or less, preferably 80 mm or less, and more preferably 65 mm or less. The lower limit of the thickness is not limited as long as it can exhibit impact resistance, but may be, for example, about 40 mm.

The floor constituent material and floor cushioning material of the present invention may have an impact acceleration G value during a fall collision, which is a numerical value indicating impact resistance, measured in accordance with the provisions of JIS A 5917 (2018), of 45 G or less, preferably 42 G or less, and more preferably 39 G or less. The lower limit of the G value is not particularly limited, but may be about 20 G, preferably about 25 G, and more preferably about 30 G.

In the case of floor components, the G value is a value measured directly, while in the case of floor cushioning materials, the G value is a value measured by placing a 5.5 mm thick plywood (flexural modulus: approximately 5.5 x 10 ³ MPa) on the upper side of the sample. Here, the flexural modulus of the plywood is a value measured in accordance with JIS K 7171 at a test piece (width 10 mm, length 100 mm) with a support distance of 80 mm and a test speed of 10 mm/min.

The flooring material of the present invention can achieve performance that is neither too hard nor too soft, so that the value calculated in a hardness test during daily operation measured in accordance with the provisions of JIS A 5917 (2018) may be, for example, 0.6 to 2.0, preferably 0.6 to 1.5, more preferably 0.7 to 1.4, and even more preferably 0.8 to 1.3.

In the case of floor components, the hardness test value during daily operation is a value measured directly. The value that can be imparted by the floor cushioning material is a value measured by placing a 5.5 mm thick plywood (flexural modulus: about 5.5 x 10 ³ MPa) on the upper side of the sample. Here, the flexural modulus of the plywood is a value measured in accordance with JIS K 7171 at a support distance of 160 mm for a test piece (width 30 mm, length 200 mm) and a test speed of 10 mm/min.
The floor constituent materials thus obtained can be used to form floors for various buildings (e.g., homes, apartment buildings, stores, dormitories, offices, hotels, school buildings, lecture halls, research laboratories, hospitals, clinics, assembly halls, public halls, stadiums, tea rooms, etc.) according to their intended use as tatami floors, wood floors, polymer sheet floors, ceramic floors, carpet floors, etc.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The various characteristics of the present invention were evaluated by the following methods.

[Compressive elastic modulus]
In accordance with JIS K7181, a first buffer layer was cut into a disk shape having a diameter of 29 mm, and compressed with a pressure plate at a test speed of 10 mm/min from a strain of 10% to 20% based on the initial thickness of the first buffer layer. The elastic modulus was measured and evaluated as the compressive elastic modulus of the first buffer layer when compressed from 10% to 20%.
In addition, in accordance with JIS K7181, a second buffer layer cut into a disk shape having a diameter of 29 mm was compressed with a pressure plate at a test speed of 10 mm/min from a strain of 2.5% to 5.0% based on the initial thickness of the second buffer layer . The elastic modulus was measured and evaluated as the compressive elastic modulus of the second buffer layer when compressed from 2.5% to 5.0%.

[Flexural modulus]
It is a numerical value measured as the elastic modulus when it changes from 0.25% to 0.5% at a test speed of 10 m/min according to the provisions of JIS K 7171. When the bending elastic modulus differs depending on the direction (e.g., MD direction, CD direction), the higher bending elastic modulus was adopted.

[Thickness (mm), apparent density (kg/m ³ )]
The basis weight (g/ ^m2 ) of the nonwoven fiber structure was measured in accordance with 6.1 of JIS L 1913 "General Testing Methods for Nonwoven Fabrics", and the thickness (mm) of the nonwoven fiber structure was measured in accordance with 6.2 of JIS L 1913 "General Testing Methods for Nonwoven Fabrics", and the apparent density (kg/ ^m3 ) was calculated from the basis weight and thickness values.

[Flexural strength]
In accordance with the provisions of JIS K 7171, the bending strength was measured by a three-point bending test method with a test piece width of 30 mm, a length of 200 mm, a support distance of 160 mm, and a test speed of 10 mm/min.

[Acceleration G value at impact during a fall collision]
In accordance with JIS A 5917 (2018), a steel head (3.75 ± 0.10 kg) was dropped vertically from directly above the test specimen at a drop height of 200 ± 5 mm, and the maximum acceleration G value when it collided with the test specimen was measured and used as an index of hardness during a fall collision. In addition, when only the floor cushioning material is used as the test specimen, the test specimen may be one in which the second cushioning layer is placed under the first cushioning layer and a 5.5 mm thick Chinese plywood (flexural modulus: 5545 MPa) is placed on the upper side of the first cushioning layer. In this case, the value obtained is considered to be approximately the same as the value obtained with the floor component of the example.

[Stiffness during everyday movements]
In accordance with JIS A 5917 (2018), a 40 kg weight was applied to the test specimen from directly above via a loading plate. The deformation energy U _F (N·cm), recovery amount D _R (cm), and recovery time T _R (s) were measured until the test specimen reached its maximum deformation. The value calculated using the following formula (1) defined in JIS A 5917 (2018) was regarded as the hardness during everyday movements.
log(U _F /9.8-8D _R・D _R・_TR ⁻¹ ) (1)
In addition, when only the floor cushioning material is used as the test specimen, the test specimen may be one in which the second cushioning layer is placed under the first cushioning layer, and 5.5 mm thick Chinese plywood (flexural modulus: 5545 MPa) is placed on the top of the first cushioning layer. In this case, the value obtained is considered to be similar to the value obtained with the floor component of the example.

[Example 1]
A tatami mat made of rush grass was used as the surface decorative material, a nonwoven fiber structure with a thickness of 2 mm and a density of 10 kg/ ^m3 (Kuraray Co., Ltd.'s "Felibendy" board type) was used as the cushion material 5, a 7 mm thick "Kohya hemp board" (flexural modulus: 700 MPa) made by Koyo Sangyo Co., Ltd. was used as the board material 1, a nonwoven fiber structure containing a moist heat adhesive fiber with a thickness of 12 mm and an apparent density of 50 kg/ ^m3 (Kuraray Co., Ltd.'s "Felibendy" board type) was used as the first buffer layer 2, and a palm board with a thickness of 15 mm (Azeas Co., Ltd.) was used as the second buffer layer 3. These materials were bonded with an adhesive in the laminated state shown in Figure 3 to obtain a floor component (thin tatami mat). The physical properties of the first and second buffer layers, the G value of the impact acceleration during a fall collision, and the hardness during daily operation of the obtained floor component are shown in Table 1.

[Example 2]
A floor constituent material (thin tatami mat) was obtained in the same manner as in Example 1, except that a 30 mm thick palm board (manufactured by Azeas Corporation) was used as the second buffer layer 3. Table 1 shows the physical properties of the first and second buffer layers, as well as the G value of the impact acceleration during a fall collision and the hardness during daily movement of the obtained floor constituent material.

[Example 3]
A floor constituent material (thin tatami mat) was obtained in the same manner as in Example 1, except that a 10 mm thick kenaf board (manufactured by Yamanaka Sangyo Co., Ltd.) was used as the second buffer layer 3. The physical properties of the first and second buffer layers, as well as the acceleration G value upon impact during a fall collision and the hardness during everyday movement of the obtained floor constituent material are shown in Table 1.

[Example 4]
A floor constituent material (thin tatami mat) was obtained in the same manner as in Example 1, except that a 20 mm thick kenaf board (manufactured by Yamanaka Sangyo Co., Ltd.) was used as the second buffer layer 3. The physical properties of the first and second buffer layers, as well as the acceleration G value upon impact during a fall collision and the hardness during everyday movement of the obtained floor constituent material are shown in Table 1.

[Example 5]
A floor constituent material (thin tatami mat) was obtained in the same manner as in Example 1, except that a 30 mm thick tatami board (manufactured by Daiken Corporation) was used as the second buffer layer 3. Table 1 shows the physical properties of the first and second buffer layers, as well as the acceleration G value at the time of impact during a tumble collision and the hardness during everyday movement of the obtained floor constituent material.

[Example 6]
A floor constituent material (thin tatami mat) was obtained in the same manner as in Example 1, except that a nonwoven fiber structure containing moist heat adhesive fibers having a thickness of 8 mm and an apparent density of 50 kg/ ^m3 ("Felivendy" board type manufactured by Kuraray Co., Ltd.) was used as the first buffer layer 2, and a 30 mm thick tatami board (manufactured by Daiken Corporation) was used as the second buffer layer 3. The physical properties of the first and second buffer layers, and the impact acceleration G value of the obtained floor constituent material during a tumble collision are shown in Table 1.

[Example 7]
A floor constituent material (thin tatami mat) was obtained in the same manner as in Example 1, except that a 30 mm-thick extruded foam polystyrene board ("Styrofoam" (TM) manufactured by DuPont-Styro Corporation) was used as the second buffer layer 3. The physical properties of the first and second buffer layers, as well as the G-value of the impact acceleration during a fall collision and the hardness during everyday movement of the obtained floor constituent material are shown in Table 1.

[Comparative Example 1]
A floor constructing material (thin tatami mat) was obtained in the same manner as in Example 1, except that the second buffer layer 3 was not provided. Table 1 shows the physical properties of the first buffer layer, the G-value of the impact acceleration during a tumble collision, and the hardness during everyday movement of the obtained floor constructing material.

[Comparative Examples 2 to 6]
Table 1 shows the acceleration G values at the time of impact during a fall collision measured for the second buffer layer 3 used in Examples 1 to 5.

[Comparative Example 7]
Table 1 shows the impact acceleration G value measured for the second buffer layer 3 used in Example 7 during a fall collision.

As shown in Table 1, Comparative Example 1 has the same structure as Example 1 except that the second buffer layer is not used, but the G value shown in the hardness test during a fall collision was 52 G. Comparative Example 2 uses only the second buffer layer used in Example 1, but the G value shown in the hardness test during a fall collision was 78 G. Example 1, despite being a combination of Comparative Examples 1 and 2, had a G value of 34 G, which was significantly lower than the G values obtained in Comparative Examples 1 and 2.

Similarly, all of Examples 2 to 7 had G values significantly lower than the G value obtained in Comparative Example 1, which had the same configuration as Example 1 except that the second buffer layer was not used, and the G value of the second buffer layer used alone in each of the examples, and all of them showed excellent impact resistance.

In addition, the hardness during everyday movements was in the range of 0.6 to 2.0 in all examples, indicating a hardness that was neither too hard nor too soft.

The floor cushioning material of the present invention can impart good impact resistance to various floor components. For example, the floor components can be useful not only as floor coverings (e.g., tatami floors, tile carpets, etc.), but also as upholstered floors (e.g., wooden floors such as hardwood floors, polymer sheet floors such as cushion flooring, tile floors such as various tiles, etc.), painted floors (e.g., wooden floors painted with synthetic or natural paints, etc.), etc.

As described above, a preferred embodiment of the present invention has been described, but various additions, modifications, and deletions are possible without departing from the spirit of the present invention, and such additions, modifications, and deletions are also included within the scope of the present invention.

REFERENCE SIGNS LIST 1 Plate material 2 First buffer layer 3 Second buffer layer 4 Surface decorative material 5 Cushion material 10 Floor buffer material 20 Floor constituent material 30 Floor constituent material

Claims (13)

A floor component comprising at least a floor cushioning material and a board material,
The floor cushioning material is at least composed of a first cushioning layer and a second cushioning layer disposed below the first cushioning layer, and the first cushioning layer is disposed below the board material,
The compressive elastic modulus of the first buffer layer when compressed from 10% to 20% is 0.01 to 29 kPa;
The second buffer layer has a compressive elastic modulus of 30 to 12,000 kPa when compressed from 2.5% to 5.0%; and
A floor construction material, wherein the flexural modulus of the plate material is 500 to 4000 MPa. The floor construction material according to claim 1, wherein the compressive elastic modulus when the second buffer layer is compressed from 2.5% to 5.0% is 50 kPa or more higher than the compressive elastic modulus when the first buffer layer is compressed from 10% to 20%. 3. The floor construction according to claim 1 or 2, wherein the second buffer layer has a bending strength of 0.2 N/ ^mm2 or more. The floor component according to any one of claims 1 to 3, wherein the thickness of the first buffer layer is 20 mm or less, and the thickness of the second buffer layer is 0.8 times or more the thickness of the first buffer layer.
Floor components. The floor construction according to any one of claims 1 to 4, wherein the first buffer layer is a nonwoven fiber structure having an apparent density of 30 to 70 kg/ ^m3 . A floor construction material according to any one of claims 1 to 5, in which the first buffer layer and the second buffer layer can be integrated with a connecting means. A floor component according to any one of claims 1 to 6, wherein the impact acceleration G value during a fall collision measured in accordance with JIS A 5917 (2018) is 45 G or less. A flooring material according to any one of claims 1 to 7, in which the first buffer layer is a nonwoven fiber structure in which fibers are fixed to each other by fusion of the moist heat adhesive fibers. The flooring material according to any one of claims 1 to 8, wherein the second buffer layer is at least one selected from the group consisting of a natural fiber molded board, a synthetic fiber molded board, an inorganic fiber molded board, and a foamed plastic board. A flooring component according to any one of claims 1 to 9, the hardness of which during daily operation, measured in accordance with JIS A 5917 (2018), is 0.6 to 2.0. A flooring material according to any one of claims 1 to 10, the thickness of which is 100 mm or less, and the impact acceleration G value measured in accordance with JIS A 6519 is 45 G or less. The flooring material according to any one of claims 1 to 11, which is a tatami flooring, a wood flooring, a polymer sheet flooring, a ceramic flooring, or a carpet flooring. A floor cushioning material used in the floor construction material according to any one of claims 1 to 12.

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