Impact-mitigating core material and impact-mitigating floor material

Abstract

Provided are a core material and a floor material that excel in impact-absorption performance, the materials thereof having a posture balance maintenance function and providing support to enable smooth movements in areas such as the daily movements of the elderly and other physically weak people, transitioning movements from lying down to standing, standing up movement from a chair, or walking.　The hardness of the surface measured in accordance with the hardness test of the JIS A 5917:2018 standard for "Impact mitigating tatami flooring" is 60 G or less, and the heavy floor impact sound level reduction amount measured in accordance with the JIS A 1440-2:2007 standard for "Acoustics -- Laboratory measurements of the reduction of transmitted impact sound by floor coverings on a solid standard floor -- Part 2: Method using standard heavy impact sources" is ΔLH-3 or greater.

Description

Impact-absorbing core material and impact-absorbing floor material

[0001] The present invention relates to a core material having excellent shock absorbing properties and a flooring material having excellent shock absorbing properties.

[0002] Shock-absorbing mats, commonly used in nursing care products, have excellent shock absorption properties, preventing injuries such as fractures when slipping or falling during actions such as transitioning from a bed to a standing position, from a bed to a wheelchair, or from a wheelchair to a bed. To achieve this, they are made of materials with excellent cushioning properties, emphasizing their shock-absorbing properties. However, simply having excellent cushioning properties can cause localized depressions when stepped on during movement or work, which can cause the care recipient's cane to get caught in the depression and make movement or work difficult. In other words, because shock-absorbing mats deform locally, they can get caught or cause the care recipient to trip when moving to the next action, making them less safe.

[0003] Furthermore, an outdoor experiment using sneakers found that 2.3% of elderly people tripped over a 10mm unevenness in the road surface (Wood Society Journal, No. 627 / V44, pp. 67-76, August 1998). Therefore, even indoors, it goes without saying that steps should be minimized, but localized deformation is also undesirable. The Housing Performance Labeling Standards established by the Ministry of Construction (now the Ministry of Land, Infrastructure, Transport and Tourism) in 2000 stipulate that, as a key point of barrier-free standards, "no steps on the floor are safer, and it is especially desirable to avoid steps in the daily living spaces of the elderly." It also states, "Measures to eliminate floor height differences mean that a height difference of no more than 3mm in design and no more than 5mm in construction is considered to be no height difference. Floor trims and thresholds for fixtures installed when floor finishing materials are changed should be within this range." In this way, in accordance with the government's barrier-free guidelines, it is preferable to keep local deformation of flooring materials to within 5 mm.

[0004] In response to the above-mentioned situation, Patent Document 1 proposes a wooden flooring material comprising a wood surface material and a shock-absorbing material laminated on the backside of the wood surface material, the shock-absorbing material having an Asker C hardness of 40 to 50 degrees and a thickness of 6 mm or more. However, [paragraph 0031] of Patent Document 1 states, "According to the present invention, it is possible to obtain a wooden floor with a G-value of 100 G or less upon impact." This level of shock-absorbing performance is insufficient to solve the above-mentioned problems. Patent Document 2 also proposes a wooden flooring material comprising a wood surface material and a shock-absorbing material laminated on the backside of the wood surface material, the shock-absorbing material having an Asker C hardness of more than 50 degrees but not exceeding 70 degrees and a thickness of 9 mm or more. However, [paragraph 0028] of Patent Document 2 states, "According to the present invention, it is possible to obtain a wooden floor with a G-value of 100 G or less upon impact." This level of shock-absorbing performance is insufficient to solve the above-mentioned problems.

[0005] JP 2011-190673 A JP 2011-190674 A

[0006] In view of the above problems, the object of the present invention is to provide a core material and flooring material with excellent shock absorption properties that support the daily movements of physically weak people such as the elderly, allowing them to move smoothly in their daily activities, such as transitioning from lying down to standing, getting up from a chair, and walking, while also having the function of maintaining balance in their posture.

[0007] First, the terms used in this specification will be explained. In this specification, a structure having an impact-absorbing layer on the underside of a board is referred to as a core material, and a structure having a decorative layer on the upper surface of a board and an impact-absorbing layer on the underside of the board is referred to as a flooring material.

[0008] To achieve the above object, the first invention of the present application is a core material having an impact-absorbing layer on the underside of the board material, characterized in that the surface hardness measured in accordance with the hardness test for "impact-absorbing tatami mats" of JIS A 5917:2018 is 60 G or less, and the reduction in heavy-duty floor impact sound levels measured in accordance with JIS A 1440-2:2007 "Laboratory measurement method for floor impact sound level reduction of floor finishing structures on concrete floors - Part 2: Method using standard heavy impact source" is △LH-3 or more.

[0009] The second invention of the present application is a method for determining compressive properties of a test piece made of a plate material and an impact absorbing layer in accordance with JIS K 7181:2011, "Plastics - Determination of Compression Properties." The planar dimensions of the test piece made of the plate material and the impact absorbing layer are 50 mm in the vertical direction and 400 mm in the horizontal direction, and the center of the test piece is compressed at a test speed of 2 mm / min using a steel ball indenter with a radius of 5 mm. When the compression load when the thickness of the impact absorbing layer becomes zero as a result of the compression is defined as the maximum compression load, the initial thickness of the impact absorbing layer is determined as th ０ The thickness of the impact absorbing layer after compression is th １ When the compressive strain is 40%, １ =th ０ × 0.6) is set to a 40% compressive load, and 60% compressive strain (th １ =th ０ × 0.4) is set to 60% compressive load, and 80% compressive strain (th １ =th ０ × 0.2) is taken as an 80% compression load, the 40% compression load is 50N to 200N, the 60% compression load is 100N to 300N, and the 80% compression load is 200N to 800N, and the 40% compression load is preferably 70N to 150N, the 60% compression load is preferably 130N to 250N, and the 80% compression load is preferably 200N to 600N.

[0010] The third invention of the present application is a core material characterized in that, in the second invention of the present application, when (compression load / maximum compression load) is the compression load ratio, the 40% compression load ratio is 0.10 or less, the 60% compression load ratio is 0.20 or less, and the 80% compression load ratio is 0.40 or less.

[0011] The fourth invention of the present application is the third invention of the present application, and in accordance with the hardness test for "impact-absorbing tatami mats" specified in JIS A 5917:2018, the planar dimensions of a test specimen consisting of a board material and an impact-absorbing layer are 830 mm in the vertical direction and 830 mm in the horizontal direction, and a predetermined amount of load is applied to the center of the test specimen from a loading plate with a diameter of 50 mm, and the amount of displacement of the center is measured as D ０ mm, and the displacement of a point 50 mm away from the center on a straight line in any direction passing through the center is D ５０ mm, and the displacement at a point 100 mm away from the center is D １００ mm, and the displacement at a point 150 mm away from the center is D １５０ mm, (D ０ -D ５０ ) mm is 1.50 mm or less, and (D ０ -D １００ ) mm is 3.00 mm or less, and (D ５０ -D １００ ) / 50 is 0.04 or less, and (D ５０ -D １５０ ) / 100 is 0.03 or less, and (D １００ -D １５０ ) / 50 is 0.025 or less.

[0012] The fifth invention of the present application is a flooring material having a decorative layer on the upper surface of the board and an impact-absorbing layer on the lower surface of the board, characterized in that the surface hardness measured in accordance with JIS A 5917:2018 "impact-absorbing tatami" floor hardness test is 60 G or less, and the reduction in heavy-duty floor impact sound level measured in accordance with JIS A 1440-2:2007 "Laboratory measurement method for floor impact sound level reduction of floor finishing structures on concrete floors - Part 2: Method using standard heavy impact source" is △LH-3 or more.

[0013] The sixth invention of the present application is the fifth invention of the present application, and in accordance with the hardness test for "impact-reducing tatami mats" specified in JIS A 5917:2018, the planar dimensions of a test specimen consisting of a board, an impact-reducing layer, and a decorative layer are 830 mm in the vertical direction and 830 mm in the horizontal direction, and a predetermined amount of load is applied to the center of the test specimen from a loading plate with a diameter of 50 mm, and the amount of displacement of the center is measured as D ０ mm, and the displacement of a point 50 mm away from the center on a straight line in any direction passing through the center is D ５０ mm, and the displacement at a point 100 mm away from the center is D １００ mm, and the displacement at a point 150 mm away from the center is D １５０ mm, (D ０ -D ５０ ) mm is 3.00 mm or less, and (D ０ -D １００ ) mm is 4.00 mm or less, and (D ５０ -D １００ ) / 50 is 0.03 or less, and (D ５０ -D １５０ ) / 100 is 0.02 or less, and (D １００ -D １５０ ) / 50 is 0.02 or less.

[0014] The core materials of the first to fourth inventions and the flooring materials of the fifth and sixth inventions of the present application can provide core materials and flooring materials with excellent shock absorption properties that support the everyday movements of physically weak people such as the elderly, allowing them to move smoothly in their daily activities, such as transitioning from lying down to standing, getting up from a chair, and walking, while also having the function of maintaining balance in body posture.

[0015] FIG. 1 is a cross-sectional view of a core material of the first embodiment. FIG. 2 is a cross-sectional view of a core material of the second embodiment. FIG. 3 is a cross-sectional view of a flooring material of the first embodiment. FIG. 4 is a cross-sectional view of a flooring material of the second embodiment. FIG. 5 is a cross-sectional view of a flooring material of the third embodiment. FIG. 6 is a cross-sectional view of a flooring material of the fourth embodiment. FIG. 7 is a cross-sectional view of a flooring material of the fifth embodiment. FIG. 8 is a diagram showing the thickness (mm) of the impact mitigation layer of the core material of Examples 1 to 6 after compression in a test to determine compression properties, as described in paragraph 0061 below, on the horizontal axis, and the compressive force (N) on the vertical axis. FIG. 9 is a diagram showing the thickness (mm) of the impact mitigation layer of the core material of Comparative Examples 1 to 6 after compression in a test to determine compression properties, as described in paragraph 0061 below, on the horizontal axis, and the compressive force (N) on the vertical axis. FIG. 10 is a diagram showing the compressibility (%) of the core material of Examples 1 to 6 after compression in a test to determine compression properties, as described in paragraph 0061 below, on the horizontal axis, and the compressive force (N) on the vertical axis. FIG. 11 is a graph showing the compressibility (%) of the core materials of Comparative Examples 1 to 6 on the horizontal axis and the compressive force (N) on the vertical axis in a test for determining the compression characteristics described in paragraph 0061 below.

[0016] Hereinafter, embodiments of the present invention will be described in detail.

[0017] 1 shows a core material 10 according to a first embodiment 1. The core material 10 according to the first embodiment includes a plate material 11 and an impact absorbing layer 12 laminated on the back surface side of the plate material 11. The total thickness of the core material 10 according to the first embodiment is, for example, 10.0 mm or more and 30.0 mm or less.

[0018] Examples of materials that can be used to make the board 11 include medium density fiberboard (hereinafter referred to as "MDF"), insulation board (soft fiberboard), hardboard (hard fiberboard), plywood, sorghum board, and resin foam board. The board 11 is preferably made of any one of these materials alone or a composite of multiple materials, and from the viewpoint of obtaining excellent shock absorption performance, it is preferable that the board 11 contains MDF. From the viewpoint of obtaining excellent shock absorption performance, the thickness of the board 11 is preferably 4.0 mm or more and 15.0 mm or less, and more preferably 3.0 mm or more and 7.0 mm or less.

[0019] Examples of materials constituting the impact absorbing layer 12 include fiber structures such as nonwoven fabric, synthetic fiber felt, and natural fiber felt, and foam materials such as synthetic resin foam and rubber foam. The impact absorbing layer 12 is preferably made of any one of these single materials or a composite of multiple materials, and from the viewpoint of obtaining excellent impact absorbing performance, it is preferable that the impact absorbing layer 12 be made of a material that includes nonwoven fabric.

[0020] The impact-absorbing layer 12 may be a laminate formed by laminating multiple constituent materials together, specifically, for example, a laminate of multiple sheets of nonwoven fabric. In this case, the multiple constituent materials may be joined by chemical joining such as using a hot melt adhesive, double-sided adhesive tape, adhesive sheet, or liquid adhesive; or mechanical joining such as sewing or tacking. The multiple constituent materials may be joined only by chemical joining, only by mechanical joining, or by a combination of chemical and mechanical joining. Furthermore, the multiple constituent materials may be joined only at their edges or corners, with the center portion left unjoined.

[0021] From the viewpoint of obtaining excellent impact absorbing performance, the thickness of the impact absorbing layer 12 is preferably 6.0 mm or more and 20 mm or less, and more preferably 8 mm or more and 15 mm or less.

[0022] The weight of the impact absorbing layer 12 is, for example, 400 g / m ２ 800g / m or more ２ The apparent density of the impact absorbing layer 12 is, for example, 0.030 g / cm ３ 0.070g / cm or more ３ The following is the result.

[0023] Examples of means for joining the plate material 11 and the shock absorbing layer 12 include chemical joining means using hot melt adhesive, double-sided tape, adhesive sheets, liquid adhesives, etc.; and mechanical joining means such as sewing or tacking with a tacker. From the viewpoint of obtaining excellent shock absorbing performance, the plate material 11 and the shock absorbing layer 12 are preferably joined together by chemical joining means, including the central portion. On the other hand, from the same viewpoint, it is preferable that the central portion of the plate material 11 and the shock absorbing layer 12 is not joined by mechanical joining means. Alternatively, the plate material 11 and the shock absorbing layer 12 may be joined only at the edges or corners, with the central portion not being joined.

[0024] The core 10 may also be provided with a second plate member on the lower surface of the impact absorbing layer 12 .

[0025] Second Embodiment Figure 2 shows a core material 20 according to the second embodiment. The core material 20 according to the first embodiment comprises a plate material 21, a first impact absorbing layer 22 laminated on the back surface of the plate material 21, and a second impact absorbing layer 23 laminated on the underside of the first impact absorbing layer 22. The configurations of the plate material 21 and first impact absorbing layer 22 of the core material 20 according to the second embodiment are the same as the configurations of the plate material 11 and impact absorbing layer 12 of the flooring material 10 according to the first embodiment, and therefore will not be described again.

[0026] Examples of materials constituting the second impact-absorbing layer 23 include fiber structures such as nonwoven fabric, synthetic fiber felt, and natural fiber felt; foam materials such as synthetic resin foam and rubber foam; elastomer plates such as rubber plates and resin plates; paper, etc. The second impact-absorbing layer 23 is preferably made of any one of these single materials or a composite of multiple materials, and from the viewpoint of obtaining excellent impact-absorbing performance, it is preferable that the second impact-absorbing layer 23 be made of a material that includes nonwoven fabric.

[0027] In order to obtain excellent impact mitigation performance, the thickness of the second impact mitigation layer 23 is preferably thinner than the thickness of the first impact mitigation layer 22, and specifically, is preferably 0.5 mm or more and 20.0 mm or less, and more preferably 2.0 mm or more and 8.0 mm or less.

[0028] The basis weight of the second impact absorbing layer 23 is, for example, 50 g / m ２ More than 300g / m２ The apparent density of the second impact absorbing layer 23 is, for example, 0.020 g / cm ３ 0.150g / cm or more ３ The following is the result.

[0029] The first impact absorbing layer 22 and the second impact absorbing layer 23 are preferably bonded together by chemical bonding means and / or mechanical bonding means.

[0030] The core material 20 may also be provided with a second plate material on the lower surface of the second impact absorption layer 23 .

[0031] (Third Embodiment) Figure 3 shows a flooring material 30 according to a third embodiment. The flooring material 30 according to the third embodiment comprises a board 31, an impact-absorbing layer 32 laminated on the back side of the board 31, and a decorative layer 33 laminated on the front side of the board 31 to provide flexibility, cushioning, heat retention, decorativeness, etc. for people to sit on or walk on. The configurations of the board 31 and impact-absorbing layer 32 of the flooring material 30 are the same as the configurations of the board 11 and impact-absorbing layer 12 of the core material 10 according to the first embodiment, so a description thereof will be omitted.

[0032] Examples of materials constituting the decorative layer 33 include resin tatami mats, Japanese paper tatami mats, natural rush tatami mats, resin sheets, synthetic fiber or natural fiber fabrics, flooring, carpets, rugs, P-tiles, cushion flooring, flooring, etc. From the viewpoint of obtaining floor surface performance such as durability, the thickness of the decorative layer 33 is preferably 0.5 mm or more and 15.0 mm or less, more preferably 0.5 mm or more and 4.0 mm or less.

[0033] The decorative layer 33 and the plate material 31 are preferably joined together by chemical joining means and / or mechanical joining means.

[0034] The flooring material 30 may also be provided with a second plate material on the underside of the impact absorbing layer 32 .

[0035] (Fourth embodiment) Figure 4 shows a flooring material 40 according to the fourth embodiment. The flooring material 40 according to the fourth embodiment comprises a board 41, a first impact-absorbing layer 42 laminated on the back side of the board 41, a second impact-absorbing layer 43 laminated on the front side of the board 41, and a decorative layer 44 laminated on the top surface of the second impact-absorbing layer 43. The configurations of the board 41, first impact-absorbing layer 42, and decorative layer 44 of the flooring material 40 are the same as the configurations of the board 31, first impact-absorbing layer 32, and decorative layer 33 of the flooring material 30 according to the third embodiment, and therefore will not be described again.

[0036] The second impact-absorbing layer 43 provides cushioning, soundproofing, and functionality to the flooring material, and is not particularly limited as long as it is made of a material that has traditionally been used as a cushion sheet for flooring materials. Examples include nonwoven fabrics, woven fabrics, mats, and felt made from fibers such as hemp fiber, cotton fiber, polyethylene fiber, polypropylene fiber, urethane fiber, polyacrylic fiber, and polyester fiber; foam sheets such as polystyrene resin foam sheets, polyethylene resin foam sheets, polypropylene resin foam sheets, urethane foam sheets, and rubber foam sheets; and cushioning sheets such as kraft paper, paperboard, thick paper, and cardboard, and functionality can be added by adding moisture absorbents, anti-mite agents, anti-fungal agents, antibacterial agents, disinfectants, air fresheners, etc.

[0037] If the apparent density of the second impact absorbing layer 43 is small, the layer is easily worn down and the cushioning properties are reduced, whereas if the apparent density is large, the sound absorption properties and soundproofing properties are reduced. Therefore, the apparent density is set to 0.04 to 0.2 g / cm ３ It is preferably made of a nonwoven fabric of fibers such as hemp fiber, cotton fiber, polyethylene fiber, polypropylene fiber, urethane fiber, polyacrylic fiber, or polyester fiber, and more preferably a polyester fiber nonwoven fabric.

[0038] The basis weight of the second impact absorbing layer 43 is set to 100 to 3000 g / m because a smaller basis weight reduces cushioning properties and a larger basis weight reduces soundproofing properties. ２ is preferable, and more preferably 150 to 500 g / m ２ is.

[0039] The thickness of the second impact absorbing layer 43 is generally 1 to 10 mm, and preferably 1.5 to 5 mm.

[0040] The floor material 40 may also be provided with a second plate material on the underside of the first impact-absorbing layer 42 .

[0041] Fifth Embodiment Figure 5 shows a flooring material 50 according to a fifth embodiment. The flooring material 50 according to the fifth embodiment includes a board 51, a first impact mitigation layer 52 laminated on the back side of the board 51, a third impact mitigation layer 54 laminated on the underside of the first impact mitigation layer 52, a second impact mitigation layer 53 laminated on the front side of the board 51, and a decorative layer 55 laminated on the top surface of the second impact mitigation layer 53. The configurations of the board 51, first impact mitigation layer 52, second impact mitigation layer 53, and decorative layer 55 of the flooring material 50 are the same as those of the board 41, first impact mitigation layer 42, second impact mitigation layer 43, and decorative layer 44 of the flooring material 40 according to the fourth embodiment, and therefore will not be described here. The third impact mitigation layer 54 may be made of the same material as the first impact mitigation layer 52. To achieve excellent impact mitigation performance, the thickness of the third impact mitigation layer 54 is preferably thinner than the thickness of the first impact mitigation layer 52.

[0042] The flooring material 50 may also be provided with a second plate material on the underside of the third impact absorbing layer 54 .

[0043] Sixth Embodiment Figure 6 shows a flooring material 60 according to a sixth embodiment. The flooring material 60 according to the sixth embodiment includes a board 61, a first impact mitigation layer 62 laminated on the rear side of the board 61, a second impact mitigation layer 63 laminated on the front side of the board 61, a third impact mitigation layer 64 laminated on the upper surface of the second impact mitigation layer 63, and a decorative layer 65 laminated on the upper surface of the third impact mitigation layer 64. The configurations of the board 61, first impact mitigation layer 62, and decorative layer 65 of the flooring material 60 are identical to the configurations of the board 41, first impact mitigation layer 42, and decorative layer 44 of the flooring material 40 according to the fourth embodiment, and therefore will not be described here. The second impact mitigation layer 63 and the third impact mitigation layer 64 may be made of the same materials as the second impact mitigation layer 53 of the fifth embodiment. The thickness of the second impact mitigation layer 63 is preferably thinner than the thickness of the third impact mitigation layer 64 to achieve excellent impact mitigation performance.

[0044] The flooring 60 may also be provided with a second plate material on the underside of the first impact absorbing layer 62 .

[0045] Seventh Embodiment Figure 7 shows a flooring material 70 according to a seventh embodiment. The flooring material 70 according to the seventh embodiment includes a board 71, a first impact mitigation layer 72 laminated on the back side of the board 71, a second impact mitigation layer 73 laminated on the underside of the first impact mitigation layer 72, a third impact mitigation layer 74 laminated on the front side of the board 71, a fourth impact mitigation layer 75 laminated on the top surface of the third impact mitigation layer 74, and a decorative layer 76 laminated on the top surface of the fourth impact mitigation layer 75. The configurations of the board 71 and decorative layer 76 of the flooring material 70 are the same as those of the board 41 and decorative layer 44 of the flooring material 40 according to the fourth embodiment, and therefore will not be described here. The first impact mitigation layer 72 and the second impact mitigation layer 73 may be made of the same materials as the first impact mitigation layer 42 of the fourth embodiment. The thickness of the second impact mitigation layer 73 is preferably thinner than the thickness of the first impact mitigation layer 72 to achieve excellent impact mitigation performance. The third impact mitigating layer 74 and the fourth impact mitigating layer 75 may be made of the same material as the second impact mitigating layer 43 of the fourth embodiment. From the viewpoint of obtaining excellent impact mitigation performance, the thickness of the third impact mitigating layer 74 is preferably thinner than the thickness of the fourth impact mitigating layer 75.

[0046] A back surface finishing material may be laminated on the underside of the core material of the first and second embodiments and the flooring materials of the third to seventh embodiments. The back surface finishing material is a sheet laminated on the flooring material for purposes such as slip prevention, reinforcement, and waterproofing. Examples of back surface finishing materials for slip prevention include anti-slip sheets made of resins with anti-slip properties, such as silicone resins, acrylic resins, and acrylic silicone resins; anti-slip sheets formed with granular, linear, or lattice-shaped convex portions of silicone resins, acrylic resins, or acrylic silicone resins on nonwoven fabrics, woven fabrics, mats, or felts made of fibers such as hemp fiber, cotton fiber, polyethylene fiber, polypropylene fiber, urethane fiber, polyacrylic fiber, or polyester fiber; and foam sheets made of polyethylene resins, polypropylene resins, polystyrene resins, or the like, on the back surface of which granular, linear, or lattice-shaped convex portions are formed. Examples of back surface finishing materials for reinforcement include kraft paper, paperboard, thick paper, corrugated cardboard, chipboard, synthetic resin sheets, and adhesive cloth tape. Examples of back surface finishing materials for waterproofing include synthetic resin sheets such as polyethylene resin, polypropylene resin, and polystyrene resin.

[0047] The floor material 70 may also be provided with a second plate material on the underside of the second impact absorbing layer 73 .

[0048] Examples of the present invention will be described below, but they are not intended to limit the present invention in any way, and various changes and modifications can be made without departing from the technical scope of the present invention.

[0049] Example 1 As Example 1 of the core material of the first embodiment shown in FIG. 1, a 4 mm thick, 0.05 g / m2 thick, medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of elasticity of 2880 MPa was attached to the back surface of the MDF. ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain the core material of Example 1.

[0050] Example 2 As Example 2 of the core material of the first embodiment shown in FIG. 1, a 3 mm thick, 0.05 g / m ... ３ The basis weight is 150g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain the core material of Example 2.

[0051] Example 3 As Example 3 of the core material of the first embodiment shown in FIG. 1, a 4 mm thick, 0.05 g / m ... ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Example 3.

[0052] Example 4 As Example 4 of the core material of the first embodiment shown in FIG. 1, a 3 mm thick, 0.05 g / m ... ３ The basis weight is 150g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Example 4.

[0053] Example 5 As Example 5 of the core material of the first embodiment shown in FIG. 1, a 4 mm thick, 0.05 g / m ... ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Example 5.

[0054] Example 6 As Example 6 of the core material of the first embodiment shown in FIG. 1, a 3 mm thick, 0.05 g / m2 thick, medium density fine board (MDF) having a thickness of 4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa was attached to the back surface of the 3 mm thick, 0.05 g / m2 thick, medium density fine board (MDF) having a thickness of 4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa. ３ The basis weight is 150g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain the core material of Example 6.

[0055] (Comparative Example 1) As a core material of Comparative Example 1, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of the board. ３ The basis weight is 240g / m ２Four needle-punched nonwoven fabrics having an initial modulus of elasticity of 50 kPa and a compressive modulus of elasticity of 117 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Comparative Example 1.

[0056] (Comparative Example 2) As a core material of Comparative Example 2, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of the board. ３ The basis weight is 150g / m ２ Two needle-punched nonwoven fabrics having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Comparative Example 2.

[0057] (Comparative Example 3) As a core material of Comparative Example 3, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa was attached to the back surface of the board. ３ The basis weight is 150g / m ２ Two sheets of thermal bond nonwoven fabric with an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded to each other with a hot melt adhesive. Further, a 2 mm thick, 0.10 g / m thick sheet was applied to the underside of the nonwoven fabric. ３ The basis weight is 240g / m ２ A needle-punched nonwoven fabric having an initial modulus of elasticity of 50 kPa and a compressive modulus of elasticity of 117 kPa was bonded to the core material of Comparative Example 3 using a hot melt adhesive.

[0058] (Comparative Example 4) As a core material of Comparative Example 4, a medium density fine board (MDF) having a thickness of 4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa was attached to the back surface of the board. ３ The basis weight is 150g / m ２ Two sheets of thermal bond nonwoven fabric with an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded to each other with a hot melt adhesive. Further, a 2 mm thick, 0.10 g / m thick sheet was applied to the underside of the nonwoven fabric. ３ The basis weight is 240g / m２ A needle-punched nonwoven fabric having an initial modulus of elasticity of 50 kPa and a compressive modulus of elasticity of 117 kPa was bonded to the core material of Comparative Example 4 using a hot melt adhesive.

[0059] (Comparative Example 5) As a core material of Comparative Example 5, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of the board. ３ The basis weight is 240g / m ２ Six needle-punched nonwoven fabrics having an initial modulus of elasticity of 50 kPa and a compressive modulus of elasticity of 117 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Comparative Example 5.

[0060] (Comparative Example 6) As a core material of Comparative Example 6, a medium density fine board (MDF) having a thickness of 4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa was attached to the back surface of the board. ３ The basis weight is 240g / m ２ Six needle-punched nonwoven fabrics having an initial modulus of elasticity of 50 kPa and a compressive modulus of elasticity of 117 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Comparative Example 6.

[0061] Compression characteristics, hardness, and reduction in heavy-duty floor impact sound level of the core materials of Examples 1 to 6 and the core materials of Comparative Examples 1 to 6: For the core materials of Examples 1 to 6 and the core materials of Comparative Examples 1 to 6, in accordance with the method for determining "Plastics - Compression characteristics" specified in JIS K 7181:2011, the planar dimensions of a test piece consisting of a plate material and an impact absorbing layer were 50 mm in the vertical direction and 400 mm in the horizontal direction, and the center of the test piece was compressed at a test speed of 2 mm / min using a steel ball indenter with a radius of 5 mm. As a result of the compression, the compression load when the thickness of the impact absorbing layer became zero was defined as the maximum compression load, and the initial thickness of the impact absorbing layer was defined as th ０ The thickness of the impact absorbing layer after compression is th １ When the compressive strain is 40%, １ =th ０ × 0.6) and 60% compressive strain (th １ =th０ × 0.4) and 80% compressive strain (th １ =th ０ × 0.2), and (compression load / maximum compression load) is the compression load rate, and the 40% compression load rate, 60% compression load rate, and 80% compression load rate"; "In accordance with the hardness test for "impact-absorbing tatami mat" of JIS A 5917:2018, the planar dimensions of the test specimen of the core material consisting of a board material and an impact-absorbing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and the acceleration when a head model was freely dropped onto the center of the test specimen was taken as the hardness of the surface of the test specimen, and the head model was dropped onto the center of the test specimen five times, and the arithmetic average value (G value) of the remaining three times excluding the first two times"; "JIS A In accordance with JIS No. 1440-2:2007 "Laboratory measurement method for floor impact sound level reduction of floor finishing structures on concrete floors - Part 2: Method using standard heavy impact source", the planar dimensions of a core material sample consisting of a plate material and an impact absorbing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and the sample was placed on a 150 mm thick reinforced concrete slab without using any adhesive or fixing jig, and an impact was applied to the center of the sample using a banging machine, and the obtained heavy floor impact sound level reduction ΔLH" is shown in Table 1 below.

[0062]

[0063] As shown in Table 1, the core materials of Examples 1 to 6 possess all of the characteristics of the present invention in terms of compression characteristics, hardness, and reduction in heavy-duty floor impact sound levels. However, the core material of Comparative Example 1 has a needle-punched nonwoven fabric as an impact-absorbing layer, and therefore lacks at least some of the characteristics of the present invention in terms of compression characteristics, hardness, and reduction in heavy-duty floor impact sound levels. The core material of Comparative Example 2 has a needle-punched nonwoven fabric as an impact-absorbing layer, and yet the impact-absorbing layer is thin, and therefore lacks at least some of the characteristics of the present invention in terms of compression characteristics, hardness, and reduction in heavy-duty floor impact sound levels. Furthermore, the core materials of Comparative Examples 3 and 4 have needle-punched nonwoven fabric as part of the impact-absorbing layer, and therefore lack at least some of the characteristics of the present invention in terms of compression characteristics, hardness, and reduction in heavy-duty floor impact sound levels. Furthermore, the core materials of Comparative Examples 5 and 6 have a needle-punched nonwoven fabric as an impact-absorbing layer, and therefore lack at least some of the characteristics of the present invention in terms of compression characteristics, hardness, and reduction in heavy-duty floor impact sound levels.

[0064] Example 7 As Example 7 of the core material of the first embodiment shown in FIG. 1, a 3 mm thick, 0.05 g / m ... ３ The basis weight is 150g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain the core material of Example 7.

[0065] Example 8 As Example 8 of the core material of the first embodiment shown in FIG. 1, a 4 mm thick, 0.05 g / m ... ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Example 8.

[0066] Example 9 As Example 9 of the core material of the first embodiment shown in FIG. 1, a 3 mm thick, 0.05 g / m ... ３ The basis weight is 150g / m ２ Five sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Example 9.

[0067] Example 10 As Example 10 of the core material of the first embodiment shown in FIG. 1, a 3 mm thick, 0.05 g / m ... ３ The basis weight is 150g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Example 10.

[0068] Example 11 As Example 11 of the core material of the first embodiment shown in FIG. 1, a medium density fine board (MDF) having a thickness of 4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa was attached to the back surface of the MDF. ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Example 11.

[0069] Example 12 As Example 12 of the core material of the second embodiment shown in FIG. 2, a 3 mm thick, 0.05 g / m ... ３ The basis weight is 150g / m ２Two sheets of thermal bond nonwoven fabric with an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded to each other with a hot melt adhesive. Furthermore, a 2 mm thick, 255 g / m2 sheet was applied to the underside of the nonwoven fabric. ２ An adhesive-treated polyethylene foam sheet having an initial modulus of elasticity of 74 kPa and a compressive modulus of elasticity of 84 kPa was adhered to the core material of Example 12 using an adhesive.

[0070] Example 13 As Example 13 of the core material of the second embodiment shown in FIG. 2, a 2 mm thick, 255 g / m2 sheet was attached to the back surface of a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of elasticity of 2880 MPa. ２ An adhesive-treated polyethylene foam sheet having an initial modulus of elasticity of 74 kPa and a compressive modulus of elasticity of 84 kPa was adhered to the underside of the polyethylene foam sheet with an adhesive. ３ The basis weight is 150g / m ２ Two sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain the core material of Example 13.

[0071] Example 14 As Example 14 of the core material of the first embodiment shown in FIG. 1, a 2 mm thick, 0.10 g / m ... ３ The basis weight is 240g / m ２ Six sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 50 kPa and a compressive modulus of elasticity of 117 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain the core material of Example 14.

[0072] (Comparative Example 7) As a core material of Comparative Example 7, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of elasticity of 2880 MPa was attached to the back surface of the board. ３ The basis weight is 150g / m ２Two needle-punched nonwoven fabrics having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Comparative Example 7.

[0073] (Comparative Example 8) As a core material of Comparative Example 8, a medium density fine board (MDF) having a thickness of 4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa was attached to the back surface of the board. ３ The basis weight is 150g / m ２ Two needle-punched nonwoven fabrics having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive to obtain a core material of Comparative Example 8.

[0074] (Comparative Example 9) The core material of Comparative Example 9 had a thickness of 20 mm and a density of 0.24 g / cm ３ The bending strength is 0.5 N / mm ２ As described above, a 30 mm thick insulation board made of polystyrene foam (Styrofoam from DuPont Styro, which meets the JIS A 9521:2017 standard for "thermal insulation materials for construction") was laminated on the back of a board (insulation board manufactured by Daiken Corporation) with a thermal conductivity of 0.05 W / m K and manufactured by a continuous wet paper-making method using wood chips as a raw material, and the two boards were laminated together to form an integrated laminate, thereby obtaining the core material of Comparative Example 9.

[0075] Displacement, hardness, and reduction in heavy-duty floor impact sound level of the core materials of Examples 7 to 14 and the core materials of Comparative Examples 7 to 9: For the core materials of Examples 7 to 14 and the core materials of Comparative Examples 7 to 9, in accordance with the hardness test for "impact-reducing tatami mats" specified in JIS A 5917:2018, the planar dimensions of a test specimen consisting of a board material and an impact-reducing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and a predetermined amount of load was applied to the center of the test specimen from a loading plate with a diameter of 50 mm, and the amount of displacement of the center was measured as D ０ mm, and the displacement of a point 50 mm away from the center on a straight line in any direction passing through the center is D ５０ mm, and the displacement at a point 100 mm away from the center is D １００ mm, and the displacement at a point 150 mm away from the center is D １５０When it is set to mm, D ０ mm and D ５０ mm and D １００ mm and D １５０ mm and (D ０ -D ５０ ) mm and (D ０ -D １００ ) mm and (D ０ -D ５０ ) / D ０ And, (D ０ -D １００ ) / D ０ And, (D ０ -D １５０ ) / D ０ And, (D ５０ -D １００ ) / 50 and (D ５０ -D １５０ ) / 100 and (D １００ -D １５０ ) / 50" and "In accordance with the hardness test for "impact-absorbing tatami mats" of JIS A 5917:2018, the planar dimensions of the test specimen of the core material consisting of a board material and an impact-absorbing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and the acceleration when a head model was freely dropped onto the center of the test specimen was taken as the hardness of the surface of the test specimen. The head model was dropped onto the center of the test specimen five times, and the arithmetic average value (G value) of the remaining three times excluding the first two times" and "JIS A In accordance with JIS No. 1440-2:2007 "Laboratory measurement method for floor impact sound level reduction of floor finishing structures on concrete floors - Part 2: Method using standard heavy impact source", the planar dimensions of a core material sample consisting of a plate material and an impact absorbing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and the sample was placed on a 150 mm thick reinforced concrete slab without using any adhesive or fixing jig, and an impact was applied to the center of the sample using a banging machine. The obtained reduction in heavy floor impact sound level ΔLH is shown in Table 2 below.

[0076]

[0077] As shown in Table 2, the core materials of Examples 7 to 14 have all the characteristics of the present invention in terms of displacement, hardness, and reduction in heavy-duty floor impact sound levels. However, the core materials of Comparative Examples 7 and 8 have a needle-punched nonwoven fabric as an impact-absorbing layer, and because the impact-absorbing layer is thin, they lack at least some of the characteristics of the present invention in terms of displacement, hardness, and reduction in heavy-duty floor impact sound levels. Furthermore, the core material of Comparative Example 9 has a thick polystyrene foam board as an impact-absorbing layer, and therefore lacks at least some of the characteristics of the present invention in terms of displacement, hardness, and reduction in heavy-duty floor impact sound levels.

[0078] Example 15 As Example 15 of the flooring material of the third embodiment shown in FIG. 3, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of the medium density fine board (MDF) having a thickness of 4 mm and a density of 0.05 g / m ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were stacked together, and each layer was bonded to each other with a hot melt adhesive. Flooring was then stacked on the surface of the MDF, and the MDF and flooring were bonded together with a hot melt adhesive to obtain the flooring material of Example 15.

[0079] Example 16 As Example 16 of the flooring material of the third embodiment shown in FIG. 3, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of a medium density fine board (MDF) having a thickness of 4 mm and a density of 0.05 g / m ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and each layer was bonded to each other with a hot melt adhesive. Cushion flooring (6 mm thick, manufactured by Toli Co., Ltd.) was laminated on the surface of the MDF, and the MDF and cushion flooring were bonded together with a hot melt adhesive to obtain the flooring material of Example 16.

[0080] Example 17 As Example 17 of the flooring material of the third embodiment shown in FIG. 3, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of a medium density fine board (MDF) having a thickness of 4 mm and a density of 0.05 g / m ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and each layer was bonded to each other with a hot melt adhesive. A carpet (6 mm thick, manufactured by Sangetsu Co., Ltd.) was laminated on the surface of the above MDF, and the MDF and carpet were bonded together with a hot melt adhesive to obtain the flooring material of Example 17.

[0081] Example 18 As Example 18 of the flooring material of the third embodiment shown in FIG. 3, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of a medium density fine board (MDF) having a thickness of 4 mm and a density of 0.05 g / m ３ The basis weight is 200g / m ２ Three sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were stacked together, and each layer was bonded to each other with a hot melt adhesive. Then, a 6 mm thick artificial marble was stacked on the surface of the MDF, and each layer was bonded to each other with a hot melt adhesive to obtain the flooring material of Example 18.

[0082] Example 19 As Example 19 of the flooring material of the seventh embodiment shown in FIG. 7, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of the medium density fine board (MDF) having a thickness of 3 mm and a density of 0.05 g / m ３ The basis weight is 150g / m ２ Three sheets of thermal bond nonwoven fabric with an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded to each other with a hot melt adhesive. A 2 mm thick polyethylene foam sheet with adhesive processing was then bonded to the underside of the nonwoven fabric with an adhesive. A 2 mm thick polyethylene foam sheet with a density of 0.2 g / cm was then laminated to the surface of the MDF. ３ The basis weight is 200g / m ２A thermal bonded nonwoven fabric having an initial modulus of elasticity of 17 kPa and a compressive modulus of elasticity of 100 kPa was laminated on top of the nonwoven fabric, and the layers were bonded together with a hot melt adhesive. A 2 mm thick adhesive-treated polyethylene foam sheet was then bonded to the top surface of the nonwoven fabric with an adhesive. A 2 mm thick tatami facing (trade name "MIGUSA" manufactured by Sekisui Seisakusho Co., Ltd.) was then laminated on top of the polyethylene foam sheet, and the polyethylene foam sheet and tatami facing were bonded together with an adhesive to obtain the flooring material of Example 19.

[0083] Example 20 As Example 20 of the flooring material of the fifth embodiment shown in FIG. 5, a medium density fine board (MDF) having a thickness of 5.5 mm, a bending strength of 37.9 MPa, and a bending modulus of 2690 MPa was attached to the back surface of the medium density fine board (MDF) having a thickness of 3 mm and a density of 0.05 g / m ３ The basis weight is 150g / m ２ Two sheets of thermal bonded nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and the layers were bonded together with a hot melt adhesive. A 2 mm thick adhesive-treated polyethylene foam sheet was then bonded to the underside of the nonwoven fabric with an adhesive, and a 2 mm thick adhesive-treated polyethylene foam sheet was then bonded to the surface of the MDF with an adhesive. A 2 mm thick tatami mat (trade name "MIGUSA" manufactured by Sekisui Seisakusho Co., Ltd.) was then laminated on top of the polyethylene foam sheet, and the polyethylene foam sheet and tatami mat were then bonded together with an adhesive to obtain the flooring material of Example 20.

[0084] (Comparative Example 10) As a flooring material of Comparative Example 10, a medium density fine board (MDF) having a thickness of 6.4 mm, a bending strength of 30.5 MPa, and a bending modulus of 2880 MPa was attached to the back surface of the MDF. ３ The basis weight is 200g / m ２ Three sheets of needle-punched nonwoven fabric having an initial modulus of elasticity of 19 kPa and a compressive modulus of elasticity of 23 kPa were laminated together, and each layer was bonded to each other with a hot melt adhesive. A carpet (6 mm thick, manufactured by Toli Co., Ltd.) was laminated on the surface of the above MDF, and the MDF and carpet were bonded together with a hot melt adhesive to obtain the flooring material of Comparative Example 10.

[0085] (Comparative Example 11) As a flooring material of Comparative Example 11, a medium density fine board (MDF) having a thickness of 4 mm, a bending strength of 40.9 MPa, and a bending modulus of 3540 MPa was attached to the back surface of the MDF. ３ The basis weight is 240g / m ２ Two sheets of needle-punched nonwoven fabric with an initial modulus of elasticity of 50 kPa and a compressive modulus of elasticity of 117 kPa were laminated together, and the layers were bonded to each other with a hot melt adhesive. A 2 mm thick, 0.20 g / m2 thick nonwoven fabric with a density of 117 kPa was then applied to the surface of the MDF. ３ The basis weight is 200g / m ２ Two sheets of needle-punched nonwoven fabric having an initial modulus of elasticity of 17 kPa and a compressive modulus of elasticity of 100 kPa were laminated together, and the layers were bonded together with a hot melt adhesive. A tatami mat was then laminated on top of the nonwoven fabric, and the nonwoven fabric and tatami mat were bonded together with an adhesive to obtain the flooring material of Comparative Example 11.

[0086] Comparative Example 12 In Comparative Example 12, a shock-absorbing mat was used as the floor material.

[0087] Displacement, hardness, and reduction in weight floor impact sound level of the floor materials of Examples 15 to 20 and the floor materials of Comparative Examples 10 to 12: For the floor materials of Examples 15 to 20 and the floor materials of Comparative Examples 10 to 12, in accordance with the hardness test for "impact-reducing tatami mats" specified in JIS A 5917:2018, the planar dimensions of the test specimen consisting of the board material and the impact-reducing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and a predetermined amount of load was applied to the center of the test specimen from a loading plate with a diameter of 50 mm, and the amount of displacement of the center was measured. ０ mm, and the displacement of a point 50 mm away from the center on a straight line in any direction passing through the center is D ５０ mm, and the displacement at a point 100 mm away from the center is D １００ mm, and the displacement at a point 150 mm away from the center is D １５０ When it is set to mm, D ０ mm and D ５０ mm and D １００ mm and D １５０ mm and (D ０ -D ５０ ) mm and (D ０ -D １００ ) mm and (D ０ -D５０ ) / D ０ And, (D ０ -D １００ ) / D ０ And, (D ０ -D １５０ ) / D ０ And, (D ５０ -D １００ ) / 50 and (D ５０ -D １５０ ) / 100 and (D １００ -D １５０ ) / 50" and "In accordance with the hardness test for "impact-absorbing tatami mats" of JIS A 5917:2018, the planar dimensions of the test specimen of the core material consisting of a board material and an impact-absorbing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and the acceleration when a head model was freely dropped onto the center of the test specimen was taken as the hardness of the surface of the test specimen. The head model was dropped onto the center of the test specimen five times, and the arithmetic average value (G value) of the remaining three times excluding the first two times" and "JIS A In accordance with JIS No. 1440-2:2007 "Laboratory measurement method for floor impact sound level reduction of floor finishing structures on concrete floors - Part 2: Method using standard heavy impact source", the planar dimensions of a core material sample consisting of a plate material and an impact absorbing layer were 830 mm in the vertical direction and 830 mm in the horizontal direction, and the sample was placed on a 150 mm thick reinforced concrete slab without using any adhesive or fixing jig, and an impact was applied to the center of the sample using a banging machine. The obtained reduction in heavy floor impact sound level ΔLH is shown in Table 3 below.

[0088]

[0089] As shown in Table 3, the flooring materials of Examples 15 to 20 have all the characteristics of the present invention in terms of displacement, hardness, and reduction in heavy-duty floor impact sound levels. However, the flooring materials of Comparative Examples 10 and 11 have a needle-punched nonwoven fabric as an impact-absorbing layer, so they lack at least some of the characteristics of the present invention in terms of displacement, hardness, and reduction in heavy-duty floor impact sound levels. Furthermore, the flooring material of Comparative Example 12 does not have an impact-absorbing layer, so it lacks at least some of the characteristics of the present invention in terms of displacement, hardness, and reduction in heavy-duty floor impact sound levels.

[0090] REFERENCE SIGNS LIST 10 Core material 11 Plate material 12 Impact mitigating layer 20 Core material 21 Plate material 22 First impact mitigating layer 23 Second impact mitigating layer 30 Floor material 31 Plate material 32 Impact mitigating layer 33 Decorative layer 40 Floor material 41 Plate material 42 First impact mitigating layer 43 Second impact mitigating layer 44 Decorative layer 50 Floor material 51 Plate material 52 First impact mitigating layer 53 Second impact mitigating layer 54 Third impact mitigating layer 55 Decorative layer 60 Floor material 61 Plate material 62 First impact mitigating layer 63 Second impact mitigating layer 64 Third impact mitigating layer 65 Decorative layer 70 Floor material 71 Plate material 72 First impact mitigating layer 73 Second impact mitigating layer 74 Third impact mitigating layer 75 Fourth impact mitigating layer 76 Decorative layer

Claims

1. A core material having an impact absorbing layer on the underside of the board, characterized in that the surface hardness measured in accordance with the hardness test for "impact absorbing tatami mats" of JIS A 5917:2018 is 60G or less, and the reduction in heavy-duty floor impact sound levels measured in accordance with JIS A 1440-2:2007 "Laboratory measurement method for floor impact sound level reduction of floor finishing structures on concrete floors - Part 2: Method using standard heavy impact source" is △LH-3 or more.

2. In accordance with "Plastics - Determination of Compression Properties" specified in JIS K 7181:2011, the planar dimensions of the test piece consisting of the plate material and the impact mitigation layer are 50 mm in the vertical direction and 400 mm in the horizontal direction, and the center of the test piece is compressed at a test speed of 2 mm / min using a steel ball indenter with a radius of 5 mm. As a result of this compression, the compression load when the thickness of the impact mitigation layer becomes zero is defined as the maximum compression load. When this is reached, the initial thickness of the impact mitigation layer is defined as th ０ The thickness of the impact absorbing layer after compression is th １ When the compressive strain is 40%, １ =th ０ × 0.6) is set to a 40% compressive load, and 60% compressive strain (th １ =th ０ × 0.4) is set to 60% compressive load, and 80% compressive strain (th １ =th ０ 2. The core material according to claim 1, wherein when the compression load at the time of compression (at 0.2×0.2) is set to an 80% compression load, the 40% compression load is 50N to 200N, the 60% compression load is 100N to 300N, and the 80% compression load is 200N to 800N.

3. A core material as described in claim 2, characterized in that, when (compression load / maximum compression load) is the compression load ratio, the 40% compression load ratio is 0.10 or less, the 60% compression load ratio is 0.20 or less, and the 80% compression load ratio is 0.40 or less.

4. In accordance with the hardness test for "impact-absorbing tatami mats" specified in JIS A 5917:2018, the planar dimensions of the test specimen consisting of the board and impact-absorbing layer are 830 mm in the vertical direction and 830 mm in the horizontal direction, and a predetermined amount of load is applied to the center of the test specimen from a loading plate with a diameter of 50 mm, and the amount of displacement of the center is measured as D ０ mm, and the displacement of a point 50 mm away from the center on a straight line in any direction passing through the center is D ５０ mm, and the displacement at a point 100 mm away from the center is D １００ mm, and the displacement at a point 150 mm away from the center is D １５０ mm, (D ０ -D ５０ ) mm is 1.50 mm or less, and (D ０ -D １００ ) mm is 3.00 mm or less, and (D ５０ -D １００ ) / 50 is 0.04 or less, and (D ５０ -D １５０ ) / 100 is 0.03 or less, and (D １００ -D １５０ 4. The core material according to claim 3, wherein σ / 50 is 0.025 or less.

5. A flooring material having a decorative layer on the upper surface of the board and an impact-absorbing layer on the lower surface of the board, characterized in that the surface hardness measured in accordance with JIS A 5917:2018 "impact-absorbing tatami" floor hardness test is 60G or less, and the weight floor impact sound level reduction measured in accordance with JIS A 1440-2:2007 "Method for measuring floor impact sound level reduction of floor finishing structures on concrete floors in laboratories - Part 2: Method using standard weight impact source" is △LH-3 or more.

6. In accordance with the hardness test for "impact-absorbing tatami mats" specified in JIS A 5917:2018, the planar dimensions of the test specimen consisting of the board, impact-absorbing layer, and decorative layer are 830 mm in the vertical direction and 830 mm in the horizontal direction, and a predetermined amount of load is applied to the center of the test specimen from a loading plate with a diameter of 50 mm, and the amount of displacement of the center is measured as D ０ mm, and the displacement of a point 50 mm away from the center on a straight line in any direction passing through the center is D ５０ mm, and the displacement at a point 100 mm away from the center is D １００ mm, and the displacement at a point 150 mm away from the center is D １５０ mm, (D ０ -D ５０ ) mm is 3.00 mm or less, and (D ０ -D １００ ) mm is 4.00 mm or less, and (D ５０ -D １００ ) / 50 is 0.03 or less, and (D ５０ -D １５０ ) / 100 is 0.02 or less, and (D １００ -D １５０ 6. The flooring material according to claim 5, wherein the value of (f) / 50 is 0.02 or less.

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