Three dimensional network structure

Abstract

The present invention provides a three-dimensional network structure that has high durability and exhibits the function of a projection for a long period of time. Provided is a three-dimensional network structure in which the overall average bulk density is 0.01-1.5 g / cm3, and in which a plurality of continuous filaments having random loops are partially fused, the three-dimensional network structure being used as a cushion, wherein: the three-dimensional network structure comprises a three-dimensional network structure body, and a plurality of protrusions that are formed on a specific surface of the three-dimensional network structure body and protrude in a thickness direction; the plurality of protrusions are continuously provided, shorter bottom parts than the top parts of the protrusions being interposed between the protrusions; and the average bulk density of at least one protrusion among the plurality of protrusions is 1.05-6 times the average bulk density of the three-dimensional network structure body.

Description

Three-dimensional network structure

[0001] The present invention relates to a three-dimensional network structure used for cushions such as mattresses, floor mats, and seat cushions.

[0002] The surface of the three-dimensional network structure mattresses of the previous patent applicants was basically smooth, and characterized by a firmness and high resilience, as shown in Patent Documents 1 to 3. Softer products were also offered for slimmer people by changing the type of resin and adjusting the nozzle shape and manufacturing method.

[0003] Patent Document 4 aims to provide a fiber molded product that is excellent in elasticity, compression resistance, heat retention, moisture absorption, sound absorption, etc., and is particularly suitable as a filling for bedding.The patent document 4 discloses a fiber molded product in which filling fibers having a crimped form are bonded three-dimensionally with an adhesive, and unevenness is provided on the entire surface of the fiber molded product, which substantially retains the crimped form and crimp properties of the fibers.

[0004] On the other hand, mattresses made of high-resilience urethane foam are widely used as an alternative material. In countries such as Japan, firmer mattresses are preferred, and firmer urethane foam is often used to prevent mattress settling.

[0005] When firm urethane foam is used as a mattress with a flat surface, it can easily injure the back and lower back, and pressure on the lower back and other areas can easily lead to bedsores. For this reason, the surface is sometimes profiled (or processed using Surface Modification Technology). Profile processing is a process that creates a "profile" (unevenness on the surface) on a sheet-like material. This profile processing creates uneven areas that come into contact with the body and areas that do not, providing a "body pressure distribution effect" and "ventilation effect." The unevenness also creates a layer of air that keeps the body cool in the summer and warm in the winter, making it comfortable to sleep on. Another benefit is that it reduces stuffiness caused by sweating, making for a more comfortable sleep.

[0006] Patent Document 5 discloses a laminated structure mattress that aims to provide a more comfortable sleep and includes a three-dimensional mesh structure, soft urethane foam layered on the three-dimensional mesh structure, and a storage body that stores the three-dimensional mesh structure and the soft urethane foam, wherein the soft urethane foam is profiled and is layered so that the surface opposite to the profiled surface is in contact with the three-dimensional mesh structure.

[0007] Patent Document 6 discloses a cushion filling material made of a mesh structure in which the thermal elongation rate of the three-dimensional mesh structure in the longitudinal direction is 0 to 8% before and after a dry hot air test, and describes that the roll surface is made to have a continuously formed uneven shape during production.

[0008] Patent Document 7 discloses a structure in which a load distribution means is provided in a three-dimensional mesh structure, and describes that the load distribution means is formed by grooves or notches provided from the front or back side of the three-dimensional mesh structure toward the inside.

[0009] Japanese Patent Application Laid-Open No. 2006-200118 International Publication No. 2016 / 125766 Japanese Patent No. 5454733 Japanese Patent Application Laid-Open No. 55-103345 Japanese Patent Application Laid-Open No. 2015-211703 Japanese Patent Application Laid-Open No. 2017-226230 Japanese Patent Application Laid-Open No. 2006-130283

[0010] When the three-dimensional network structures shown in Patent Documents 1 to 3 are used as mattresses, further adjustments to the sleeping comfort are necessary to attract consumers with a wide range of body types. Although there are products such as two-layer molded products including a hard lower layer and a soft upper layer, and three-dimensional network structures in which the hardness of the mattress varies depending on the area, these are still not sufficient.

[0011] The three-dimensional network structure shown in Patent Document 4 is made by bonding crimped fibers together with an adhesive. Because the adhesive is an essential component, the structure may easily become worn out, leaving durability issues. Furthermore, the structure lacks technical consideration for human body types, such as slim body types.

[0012] Mattresses using profiled urethane foam, such as those described in Patent Document 5, have several problems: there is a global trend away from urethane; most profiled urethane foam products use high-resilience urethane foam, which means that slim users only feel a slight unevenness and have little clear benefit; and pursuing softness can lead to rapid sagging. Furthermore, the raised portions of the profiled urethane foam may collapse, impairing breathability. This naturally leads to mold and mildew growth. Because the raised portions are not durable, the effects of profiling do not last long enough. Furthermore, even with profiled urethane foam mattresses, there are problems such as little acupressure effect and difficulty turning over in bed.

[0013] Furthermore, urethane foam mattresses tend to bottom out due to weight distribution. It is said that when sleeping, 44% of the weight of the entire body is carried by the lower back, and 33% by the back. The weight varies depending on the part of the body, and measures to address this are necessary, but appropriate solutions and manufacturing methods are still under development. This makes it difficult to achieve the ideal sleeping position (a gentle S-shape).

[0014] In the network structure of Patent Document 6, even if the roll surface is continuously unevenly formed during production, downward slippage occurs, which can reduce the bulk density of the convex portions of the molded product or cause them to be damaged. In addition, since a surface layer cannot be formed, the functions of the convex portions, such as the finger pressure effect, are poor, and the durability of the convex portions is also poor.

[0015] The network structure of Patent Document 7 has convex portions with flat upper surfaces, so the acupressure effect is low, and the durability of the convex portions and the compression durability of the structure are insufficient.

[0016] For example, when used as a cushioning material for floor cushions or footrests for office chairs, a three-dimensional network structure that provides an acupressure effect due to the unevenness is required, and the protrusions must be durable.

[0017] The present invention provides a three-dimensional network structure that enhances the acupressure effect and breathability functions due to the projections on its surface, and that can maintain these functions for a long period of time by increasing its durability.

[0018] The present invention is directed to a method for producing a granular material having an overall average bulk density of 0.01 to 1.5 g / cm 3 The three-dimensional network structure is used as a cushion and is formed by partially fusion-bonding a plurality of continuous filaments having random loops, and comprises a three-dimensional network structure main body and a plurality of protrusions formed on a specific surface of the three-dimensional network structure main body and protruding in the thickness direction, the plurality of protrusions being provided continuously with bottoms interposed therebetween that are lower in height than the tops of the protrusions, and the average bulk density of at least one of the plurality of protrusions is 1.05 to 6 times the average bulk density of the three-dimensional network structure main body.

[0019] Here, the "protrusions" are defined as the portions above an imaginary line connecting the upper ends of the bases, and the "average bulk density of the three-dimensional network structure body" is defined as the average bulk density of the portion excluding the protrusions formed on the upper and / or lower surfaces.

[0020] The term "cushion" as used herein includes mattress filling, vehicle seat filling, chair filling, pillow filling, floor cushion, etc. Applications include those for pets, medical, veterinary, dental, cushions, for the disabled, sports, mountain climbing, camping, training, competitions, and exercise equipment including rehabilitation.

[0021] The shape of the "cushion" includes not only a rectangular parallelepiped and a cube, but also irregular shapes such as a curved shape, a pillow shape, an oval shape, or a combination thereof. The object can be achieved by providing a plurality of protrusions on a specific surface of the cushion.

[0022] The shape of the convex portions is preferably bowl-shaped, conical, mountain-shaped (excluding those with flat tops), or polygonal pyramid-shaped, and the plurality of convex portions are arranged continuously in a first direction with intervening bottoms that are shorter than the tops of the convex portions, and the plurality of convex portions are arranged continuously in a second direction perpendicular to the first direction with intervening bottoms that are shorter than the tops of the convex portions.

[0023] The convex portions and the bottom portion each have a surface layer having a bulk density higher than the average bulk density inside the three-dimensional network structure body, and it is preferable that the surface layer at the bottom portion is thicker than the surface layer at the top portion of the convex portions, or that a high-density portion exists continuously directly below the surface layer at the bottom portion.

[0024] Here, the "inside of the three-dimensional network structure main body" refers to the part excluding the high-density surface layer present in the three-dimensional network structure main body and the high-density side portion, if any.

[0025] It is preferable that the plurality of protrusions have a surface layer and a central portion covered with the surface layer, and that the surface layer has a higher bulk density than the central portion.

[0026] The average bulk density of the central portion of at least one of the plurality of protrusions is preferably higher than the average bulk density of the interior of the three-dimensional network structure body.

[0027] The number of the protrusions is 1 m 2 It is preferable that the number of particles is 100 to 2500 per particle.

[0028] It is preferable that the protrusions are laminated with at least one of urethane foam, nonwoven sheet, and another three-dimensional network structure, or that the protrusions are covered with urethane foam, nonwoven fabric, or double raschel fabric.

[0029] Here, "another three-dimensional network structure" includes those with a flat surface, those with streak-like protrusions on one or both sides, and those with bowl-shaped, cone-shaped, mountain-shaped, or other protrusions arranged in series, staggered, or lattice patterns.

[0030] The arrangement of the protrusions is preferably in a linear, staggered, or lattice pattern.

[0031] The height or average bulk density of the protrusions preferably varies depending on the region of the three-dimensional network structure.

[0032] The convex portions are preferably formed on the upper and lower surfaces of the three-dimensional network structure body, and the shape, bulk density, height, or arrangement of the convex portions formed on the upper surface is preferably different from that of the convex portions formed on the lower surface.

[0033] It is preferable that a depression or a slope is formed by thermal processing or ultrasonic processing on the specific surface on which the projections are formed, and the projections remain in the depression or slope.

[0034] It is preferable that at least two opposing side surfaces have high density side portions having a density higher than the average bulk density of the three-dimensional network structure body.

[0035] It is preferable that the three-dimensional network structure is provided with an elongation prevention member that prevents the three-dimensional network structure from elongating in the longitudinal or lateral direction, and that the elongation prevention member is a high-density side portion that is present on at least two opposing sides and has a higher density than the average bulk density of the three-dimensional network structure body.

[0036] The present invention also relates to a seat cushion, a mattress, a pillow, or a chair, which includes the three-dimensional network structure.

[0037] The three-dimensional network structure of the present invention has the effect of improving acupressure and breathability. By increasing the bulk density of the protrusions, the resilience and durability of the protrusions are increased. Load distribution can also be improved, and when used in a mattress, for example, it becomes easier to turn over in bed. The high bulk density of the protrusions and the thicker surface high-density layer at the bottom than the protrusions increase the compression durability of the structure itself.

[0038] The load distribution properties of the three-dimensional network structure can be adjusted by the surface layer of the protrusions, the bulk density, the size and shape of the protrusions, and the number of protrusions per area, making it possible to provide a cushion with performance and functionality suited to the user's body type and preferences. For example, a three-dimensional network structure that provides a soft feel for a thin user can be provided by adjusting the surface layer, bulk density, size, etc. of the protrusions. Furthermore, by varying the height and bulk density of the protrusions in different regions, a feel tailored to each part of the body can be obtained. The durability of the protrusions can be further improved by increasing the number of fusion points, fusion strength, and bulk density of the filaments.

[0039] 1 is a plan view of a sheet of the three-dimensional network structure of the first embodiment; a perspective view of the same; an enlarged plan view of the same; and a bottom view of the same. A schematic cross-sectional view of the same three-dimensional network structure (schematic cross-sectional view A-A in FIG. 1). A perspective view of a mattress of the three-dimensional network structure of the second embodiment; a perspective view of the same from a different angle; an enlarged plan view of the same; a bottom view of the same; an enlarged bottom view of the same; and a schematic cross-sectional view of the same three-dimensional network structure. FIGS. 12A to 12E are schematic diagrams of the manufacturing process of the three-dimensional network structure. FIGS. 13A and 13B are diagrams explaining the processing of the three-dimensional network structure. FIGS. 14A to 14E are diagrams explaining high-density portions of the three-dimensional network structure.

[0040] A three-dimensional network structure 1 (hereinafter also simply referred to as structure 1) of a first embodiment will be described with reference to Figures 1 to 5. Note that the following embodiments are merely examples of the present invention, and the present invention is not limited to the following embodiments. Structure 1 is a three-dimensional spring structure in which random loops made of continuous filaments made of thermoplastic resin are welded to each other in a molten state.

[0041] The structure 1 can be used as a cushion, for example, as a seat cushion for a chair or a vehicle seat. Figures 1 to 4 show the structure cut appropriately for the purpose of explanation, and the dimensions after cutting are 45 cm long x 45 cm wide x 3 cm maximum thickness. It has a three-dimensional network structure in which a plurality of continuous filaments having random loops are partially fused, and is a hexahedron with an upper surface 1a, four side surfaces 1b, and a lower surface 1c. The overall average bulk density is 0.01 to 1.5 g / cm ３ is preferably 0.01 to 1.2 g / cm ３ is more preferable.

[0042] As shown in Figures 1, 2, and 5, on the top surface 1a of the structure 1, bowl-shaped convex portions 2 protruding in the thickness direction (Z direction) are formed in a staggered pattern in plan view. On the top surface 1a, multiple columns R are formed, with multiple convex portions 2 arranged with their bottoms 3 in the X direction, and multiple rows L are formed, with multiple convex portions 2 arranged with their bottoms 3 in the Y direction, perpendicular to the X direction. As shown in Figure 5, the convex portions 2 and bottoms 3 have a wave-like shape in cross-section in the X and Y directions. The bottoms 3 are the lowest surface portions in a specific or entire region in side view and are also the boundaries between the convex portions 2 (see Figure 5). On the top surface 1a, the bottoms 3 are also arranged in a staggered pattern in plan view. The convex portions 2 are formed over the entire top surface 1a of the structure 1, but this is not limited thereto. They may be formed only in certain regions, such as the waist or shoulders.

[0043] The plurality of protrusions 2 are formed continuously with the bottoms 3 interposed therebetween. 2 The number of protrusions 2 is preferably 100 to 2,500, and more preferably 250 to 450 per unit area. The shape of the protrusions 2 is a bowl-like shape with a rounded top, but is not limited to this and may be a cone-like, mountain-like, or polygonal pyramid. In order to improve the acupressure effect, it is preferable that the tops of the protrusions 2 do not have a flat surface. Furthermore, the height, shape, and bulk density of each protrusion 2 may be uniform, may vary depending on the region, or may be a mixture of these. The protrusions 2 may have a shape including two or three tops. The shape of the protrusions 2 is preferably not undercut or reverse tapered. The arrangement of the protrusions 2 is not limited to a staggered pattern and may be a linear or lattice pattern, and is determined according to requirements.

[0044] As shown in Figures 4 and 5, streak-like protrusions 4 and streak-like bottoms 5 that protrude in the thickness direction (-Z direction) are provided on the lower surface 1c of the structure 1 in the extrusion direction during manufacturing. The height of the streak-like protrusions 4 is preferably 4 to 70 mm. The streak-like protrusions 4 and streak-like bottoms 5 may be provided in a direction perpendicular to the extrusion direction. The streak-like protrusions 4 are formed over the entire lower surface 1c of the structure 1, but are not limited to this and may be formed only in a partial region.

[0045] Examples of the main material constituting the continuous filament include polyolefin resins such as polyethylene resins and polypropylene resins, polyethylene thermoplastic elastomers, polyester thermoplastic elastomers, propylene thermoplastic elastomers, and mixtures thereof. The material may also contain functional materials such as flame retardants and flame retardants, and if the filament is to be colored, a colored masterbatch is mixed in during melting.

[0046] The filament constituting the structure 1 may have a cross section that is solid, hollow, or irregular, as appropriate. The diameter of the filament is preferably 0.1 to 3.0 mm, more preferably 0.3 to 1.5 mm, in the case of a solid filament, and is preferably 0.2 to 5.0 mm in the case of an irregular or hollow filament.

[0047] Structure 1 in FIGS. 1 to 4 is an example of the present invention, and has an average bulk density of 0.068 g / cm 3 The filament is made of polyethylene resin, is solid, has a diameter of 1.0 mm, is gray in color, and has 1 m of protrusions 2. 2 There are 355 per piece.

[0048] The cross-sectional view of Figure 5 is a schematic diagram illustrating the bulk density of structure 1. Structure 1 comprises a three-dimensional network structure main body 11 (hereinafter also simply referred to as main body 11), a plurality of convex portions 2 formed on the upper surface thereof, and a plurality of streak-like convex portions 4 formed on the lower surface thereof. Bottom portion 3 is located on the upper surface of main body 11. Streak-like bottom portion 5 is located on the lower surface of main body 11. Main body 11, convex portions 2, and streak-like convex portions 4 are all integrally formed and have a structure in which a plurality of continuous filaments having random loops are partially fused together.

[0049] The upper surface 1a and lower surface 1c of the structure 1 have surface layers 2a, 11a, 4a, and 11e, each having a thickness of, for example, 2 to 4 mm, and each having a bulk density higher than the average bulk density of the main body 11 or the average bulk density of the interior 11c of the main body 11. In the surface layers, the loop-shaped filaments preferably lie flat in a shape that conforms to the surface shape of the structure 1. The main body 11 includes a surface layer 11a (present only in the bottom 3), an interior 11c, and a surface layer 11e (present only in the striated bottom 5). The surface layer 2a is present on the surface of the protrusions 2 and is continuous with the surface layer 11a in the bottom 3. Similarly, the surface layer 4a is present on the surface of the striated protrusions 4 and is continuous with the surface layer 11e in the striated bottom 5.

[0050] As shown in Figure 5, the surface layer 11a at the bottom 3 is thicker than the surface layer 2a at the tops of the protrusions 2, or a high-density portion exists directly below the surface layer 11a. The presence of a thick high-density portion or thick surface layer in the region near the bottom 3 firmly supports the protrusions 2, contributing to improved durability of the protrusions 2 and improved compression durability of the structure 1. If the surface layer 2a at the tops of the protrusions 2 is too thick, it becomes difficult to feel the cushioning, which is undesirable, so it is preferable to thicken the high-density surface layer at the bottom without thickening the surface layer 2a. Similarly, the surface layer 11e at the striated bottom 5 is thicker than the surface layer 4a of the striated protrusions 4, or a high-density portion exists directly above the surface layer 11e.

[0051] The protrusions 2 have a surface layer 2a and a central portion 2b covered by the surface layer 2a. The bulk density of the surface layer 2a is preferably 1.1 to 3 times the average bulk density of the central portion 2b. The average bulk density of the central portion 2b is preferably 1.05 to 3 times the average bulk density of the interior 11c of the main body 11 (the portion of the main body 11 excluding the surface layers 11a and 11e). The average bulk density of each protrusion 2 (including the surface layer 2a and the central portion 2b) is preferably 1.05 to 6 times, and more preferably 1.05 to 4 times, the average bulk density of the main body 11 (including the interior 11c and the surface layers 11a and 11e). The average bulk density of each protrusion 2 (including the surface layer 2a and the central portion 2b) is preferably 1.05 to 7 times the average bulk density of the interior 11c. The bulk density of the surface layer 2a or 4a is preferably 1.05 to 7 times, and more preferably 1.4 to 5 times, the average bulk density of the main body 11 (including the inner portion 11c and the surface layers 11a and 11e). The bulk density of the central portion 2b does not need to be constant within the central portion 2b, and for example, the central portion 2b may be formed of two layers, upper and lower, having different bulk densities.

[0052] The streak-like protrusions 4 have a surface layer 4a and a central portion 4b covered by the surface layer 4a, and the bulk density of the surface layer 4a is preferably 1.1 to 3 times that of the central portion 4b. The bulk density of the central portion 4b is preferably 1.05 to 3 times greater than that of the interior portion 11c of the main body 11. The average bulk density of the streak-like protrusions 4 (including the surface layer 4a and the central portion 4b) is preferably 1.05 to 4 times that of the main body 11 (including the interior portion 11c, the surface layer 11a, and the surface layer 11e of the streak-like bottom portion 5). The side surfaces of the structure 1 are flat. By forming the upper surface 1a and the lower surface 1c with different protrusion patterns, the user can choose between the upper surface 1a and the lower surface 1c depending on their physical condition, preference, and usage method. On the lower surface 1c, instead of the streak-like convex portions 4, a plurality of convex portions 2 similar to those on the upper surface 1a or different in height H1, width W, hardness, and arrangement from the convex portions 2 on the upper surface may be formed in a staggered, lattice, or serial pattern.

[0053] The bulk density and other measurements are taken by measuring the area above the imaginary line V1 (see Figure 5) connecting the upper ends 39 of the bottom 3 as the convex portion 2. Similarly, the area below the imaginary line V2 connecting the lower ends 59 of the striated bottom 5 is measured as the striated convex portion 4. The bulk density of the central portion 2b, 4b and the interior 11c is measured by defining the thickness of the surface layer and cutting out a portion of the same thickness from the surface. The high average bulk density of the convex portions 2 and striated convex portions 4 increases the durability of the convex portions 2 and striated convex portions 4. This allows the functions of breathability, load distribution, and acupressure effect to be maintained for a long period of time.

[0054] Of the multiple protrusions 2, at least one, preferably 50% or more, and more preferably 90% or more of the protrusions 2 has a surface layer 2a and a central portion 2b covered by the surface layer 2a, and it is preferable that the average bulk density of the protrusion 2 is higher than the average bulk density of the main body 11.

[0055] As shown in Figure 5, the width W in the X direction and the Y direction of the protrusions 2 (which correspond to the widths of the columns R and rows L) are preferably 8 to 70 mm, and the height H1 of the protrusions 2 (the difference in height between the tops of the protrusions 2 and the upper ends 39 of the bottoms 3) is preferably 3 to 70 mm. The height H1 of the protrusions 2 may be uniform across the entire cushion, or may be non-uniform as required. Furthermore, the height H2 of the striated protrusions 4 (the difference in height between the tops of the striated protrusions 4 and the lower ends 59 of the striated bottoms 5) is preferably 3 to 70 mm.

[0056] The structure 1 is intended for a seat cushion, but can also be applied to a mattress, a pillow, or a chair or its filling.

[0057] The structure 1 may be a single piece, but when used as a mattress, for example, it may be divisible into multiple pieces to facilitate transportation and storage, or to allow the convex portions to be adjusted to suit individual preferences. For example, if the structure 1 is divided into three pieces longitudinally, each of the three structures 1 may be housed in a cover or inner cover, and the covers may be joined together for use. In this case, the hardness, presence or absence of unevenness, bulk density, arrangement and height of the convex portions, bulk density of the convex portions, and size and shape of the convex portions can be changed depending on the divided parts of the structure 1, and further depending on the front and back of the divided parts. Furthermore, when another structure is stacked on the structure 1, the material and shape of the laminate can be changed depending on the divided parts.

[0058] For example, one possible combination is to use a convex portion formed in the middle section of the three sections (the section that comes into contact with the user's waist), while the other sections (the sections that come into contact with the user's head and feet) may not have convex portions or may have convex portions that are lower in height than the middle section. Furthermore, the middle section of the three sections may be adjusted to have a convex portion with a higher bulk density than the other sections. Here, the structure 1 may be made foldable by forming bending portions such as cuts without being completely divided.

[0059] When used as a mattress, the structure 1 is also preferably rollable. In this case, the average bulk density is 0.02 to 0.09 g / cm ３ When the structure 1 is used as a filling for a pillow, it is preferable that the bulk density is relatively lower than that of a mattress. In this case, the average bulk density is 0.01 to 0.07 g / cm ３ It is preferable that:

[0060] It is also preferable to laminate a sheet made of urethane foam and / or a nonwoven sheet or solid cotton on the upper or lower surface of the structure 1. It is also preferable to laminate another three-dimensional network structure having a smooth or uneven surface. For example, a sheet having a bulk density of 10 to 90 kg / m on the upper or lower surface of the structure 1 having a size of 5 to 300 mm is preferably laminated. ３ More preferably, it is 20 to 60 kg / m ３It is preferable to laminate a sheet made of urethane foam having a thickness of 2 to 50 mm, more preferably 4 to 25 mm. Furthermore, a sheet made of urethane foam, a spring, or a nonwoven fabric may be embedded in the cover that covers the structure 1 and fixed to the side fabric by quilting or the like.

[0061] To enhance the massage effect of finger pressure, a vibrator may be built into the interior or lower part of the structure 1. In this case, a hollow vibrator housing portion is formed inside or at the lower part of the structure and located below at least some of the convex parts, and the vibrator is housed inside the hollow vibrator housing portion.

[0062] The structure 1 can have various forms, such as those with hard edges, those with different surface layer thicknesses on the front and back, those with different softness on the front and back, and those with holes inside. Furthermore, depending on the intended use, the hardness can be partially changed by changing the bulk density depending on the part. Furthermore, the interior 11c of the structure may have a coarse-dense structure in which sparse parts with low bulk density and dense parts with high bulk density are alternately arranged in the extrusion direction. The interior 11c of the structure may also be formed by stacking multiple layers with different bulk densities one above the other.

[0063] The thickness of the structure 1 is significantly related to softness and resilience characteristics, and is therefore 10 mm to 400 mm, more preferably 25 to 150 mm, and even more preferably 30 to 110 mm. If the thickness is 10 mm or less, when unevenness is formed, the thickness of the base portion and the convex portion will each be about 5 mm, and cushioning properties will not be fully exhibited. In addition, the proportion of the surface layer in the convex portion will be too large, impairing cushioning properties, and the height of the convex portion will be a maximum of about 6 mm, which may make it difficult for the body to feel the effects of the convex portion. A thickness of 25 mm or more can provide functions such as cushioning and acupressure, and a thickness exceeding 60 mm can incorporate sufficient functions. A thickness greater than 400 mm is not preferable because no further functional improvement can be expected.

[0064] The dimensions of this structure 1 can be exemplified as, for example, a width of 600 to 2000 mm, a length of 1300 to 2500 mm, and a height of 30 to 120 mm for a mattress, and a width of 250 to 500 mm, a length of 300 to 800 mm, and a height of 40 to 120 mm for a pillow, but are not limited to these.

[0065] Incidentally, the structure 1 according to this embodiment is expected to have a finger pressure effect due to the protrusions. However, if this effect is too great, the protrusions may press on the structure body during use, causing the structure 1 to stretch in the longitudinal or lateral direction, which may result in a reduction in the unevenness effect and cushioning properties of the structure 1. Therefore, the structure 1 is preferably provided with an extension prevention member. Specifically, as shown in FIG. 14, it is preferable that the side surface be provided with a high-density side portion 18 having a bulk density higher than the bulk density of the interior of the structure 1. Note that, for the sake of simplicity, the protrusions are shown on only a portion of the surface in FIG. 14. The bulk density of the high-density side portion 18 is, for example, 0.25 to 2.0 g / cm. 3 The width of the high density side portion is preferably 5 to 100 mm.

[0066] For example, when used as a mattress (see A and B in Figure 14), it is preferable to provide high-density side portions 18 on two longitudinal sides and / or two lateral sides. This allows the structure to stretch in the lengthwise or lateral direction, preventing a decrease in the acupressure effect and cushioning. Furthermore, when the mattress is, for example, foldable in three or a three-piece mattress, it is possible to prevent gaps from forming between the halves of the mattress due to partial stretching of the structure in the lengthwise direction during use. When used as a seat cushion (see D and E in Figure 14), it is preferable to provide high-density bulk side portions 18 on two lateral and / or longitudinal sides.

[0067] Another effective method for preventing the structure 1 from being stretched in the longitudinal or lateral direction due to the protrusions pressing against the structure body during use is to increase the bulk density of a portion in the thickness direction (see C in Figure 14). The high density portion 19 in the thickness direction has a bulk density of, for example, 0.25 to 2.0 g / cm. 3 Examples of such high density portions include a thickness of 5 to 50 mm. Such high density portions can be formed by increasing the amount of raw material supplied to the relevant portion in the manufacturing method described below, or by performing compression molding at the relevant portion.

[0068] Next, a three-dimensional network structure 101 (hereinafter also simply referred to as structure 101) of a second embodiment will be described. This structure 101 is basically the same as structure 1, so differences will be mainly described. The structure 101 of this embodiment is used, for example, as a mattress. The filaments are solid, nearly transparent, and made of polyethylene-based resin with a filament diameter (diameter) of approximately 0.7 mm.

[0069] The structure 101 shown in Figures 6 to 10 has been appropriately cut for the purpose of explanation, and the dimensions after cutting are 46 cm in length, 43 cm in width, and 8 cm in maximum thickness. The structure 101 is a hexahedron with an upper surface 101a, four side surfaces 101b, and a lower surface 101c, and has an overall average bulk density of 0.068 g / cm ３ The upper surface 101 a includes a protrusion 102 and a bottom 103 .

[0070] The convex portions 102 are regions on the upper surface 101a that protrude upward in the thickness direction at intervals, and are multiple portions arranged in a staggered pattern. The side surface 101b and the lower surface 101c are flat surfaces. The hardness of the convex portions 102 can be adjusted by changing the bulk density of the convex portions. It is also possible to provide the lower surface 101c with the same unevenness as the upper surface 101a. It is also possible to provide the upper surface 101a and the lower surface 101c with unevenness of different convex heights.

[0071] As shown in Figure 11, the protrusions 102 include a surface layer 102a and a central portion 102b covered with the surface layer 102a. A surface layer 111d having a higher bulk density than the interior 111c of the three-dimensional network structure main body 111 (hereinafter also simply referred to as the main body 111) is formed on the lower surface 101c side of each structure 101. The surface layer 102a has a bulk density 1.1 to 3 times higher than that of the central portion 102b. The bulk density of the central portion 102b is preferably 1.05 to 3 times the bulk density of the interior 111c of the main body 111 (the portion excluding the surface layers 111a and 111d). The average bulk density of the protrusions 102 (the portion including the surface layer 102a and the central portion 102b) is 1.05 to 4 times the average bulk density of the main body 111 (the portion including the surface layer 111a, the inner portion 111c, and the surface layer 111d). 2The number of pieces per one piece is 414. The high average bulk density of the protrusions 102 and the presence of the surface layer 102a improve the acupressure effect and increase durability.

[0072] The three-dimensional network structure 1, 101 can be used for mattresses, vehicle seats, chairs, or their filling materials. It can be used for a wide range of purposes, such as health equipment for shiatsu on the lower back, soles of the feet, and calves, and as a health promotion and maintenance device. Furthermore, adding a vibration generator with a massage function inside the device can provide even greater benefits. When used in combination with sound or VR devices, it can become a device that can be used comfortably for long periods of time.

[0073] Next, an example of a method for producing the three-dimensional network structures 1 and 101 of the present embodiments 1 and 2 will be described, but the method is not limited to this. As described in JP 2001-328153 A and the like, raw materials are melted at a melting temperature that is 10°C to 20°C higher than their melting points, and the molten raw materials are sent into a die, where pressure is applied. Each filament is extruded from the extrusion port of the lower die, and due to the arrangement of multiple extrusion holes, it becomes a filament assembly consisting of multiple filaments and naturally falls.

[0074] The temperature range inside the die can be set to 100 to 400°C, more preferably 120 to 350°C, and the extrusion rate can be set to 20 to 200 kg / HR, etc. The pressure inside the die can be, for example, the discharge pressure of a 75 mm screw, and the pressure range is about 0.2 to 25 MPa.

[0075] The diameter of the die inside the die corresponds to the diameter of the filaments of the structure, and is preferably 0.1 to 5.0 mm, more preferably 0.4 to 1.8 mm.

[0076] Next, the material is caught by a pair of left and right shooters (see International Publication No. WO2012 / 157289) supplied with water or hot water, and the filaments are brought into contact with each other in a molten state, fused together, and allowed to land on the water surface while forming a three-dimensional structure. The loop diameter and filament diameter are determined by the angle of the shooters, the amount of water supplied, the diameter of the extrusion nozzle, the distance between the nozzle face, the shooters, and the take-up conveyor, the melt viscosity of the resin, the diameter of the extrusion nozzle hole, and the discharge rate. The wire diameter (diameter) is 0.1 to 5.0 mm, and the average diameter (length) of the random loops is 5 to 50 mm.

[0077] Among the wire assembly, the wires located on the outer long side come into contact with the inclined surface on which the water from the pair of long chutes is flowing, disrupting their vertical descent trajectory and causing them to intertwine with adjacent wires in a loop, sliding down the inclined surface while being carried by the water or heated water supplied from the supply pipe. At this time, the wires are directly affected by gravity, intertwining along the inclined surface and forming loops. A pair of short chutes may be provided, or a single chute may be provided. Alternatively, no chutes may be provided.

[0078] When a chute is provided, the filaments of the filament assembly that descend without coming into contact with any of the inclined surfaces of the chute pass through the forming opening. At this time, those filaments that pass near the bottom edge of the inclined surface come into contact with filaments sliding down the inclined surface and become entangled in a loop, and the disturbance of the descending trajectory caused by this contact and entanglement spreads to a small extent to the adjacent filaments toward the center as they descend. Of the filaments that pass through the forming opening, those that pass near the center of the opening land on the water surface, and because the take-up speed by the take-up machine described below is slower than the descending speed of the filament assembly, the filaments that land on the water bend and become entangled in a roughly loop near the water surface.

[0079] While being cooled in a water bath, the three-dimensional network structure is taken down by a pair of take-up machines at a speed slower than the descent of the assembly, and is clamped by the take-up machines to undergo a supplementary compression action. The take-up speed is preferably 5 to 40 m / hour. The take-up machines take up the filament assembly using an endless conveyor with a caterpillar structure (see International Publication No. WO2012 / 157289). When the filament assembly descends to the position of the endless conveyor, it has not yet completely cooled and solidified due to submersion in water, so it is clamped by the take-up machines to achieve a compression molding effect. When the filament assembly is taken up by the take-up machines and sent out, the molten filament assembly is cooled and solidified by the water, and finally the shape is fixed. It is then clamped between rollers and drawn out of the cooling bath.

[0080] A method for forming convex portions on the upper and / or lower surfaces of the three-dimensional network structure includes, for example, cutting the continuous three-dimensional network structure to an appropriate size after cooling and solidifying, and then using hot plates on the upper and / or lower surfaces of the three-dimensional network structure to hold the three-dimensional network structure between the hot plates, or placing the lower surface on a support table and applying hot plates from above to mold and compress the structure to form the convex portions 2. The convex portions can be formed in the same positions on the front and back of the structure 1, or can be formed in shifted positions, and the convex portions can have different patterns or sizes on the front and back.

[0081] Another method for forming the protrusions 2 on the upper surface of the three-dimensional network structure 1 is to attach a concave-convex part with a pressing function (shape, material, etc.) for clamping the structure to the above-mentioned take-up device (endless conveyor), and then form the protrusions on the structure by the compression action of the take-up device before the structure solidifies by cooling. When forming staggered protrusions, a concave-convex part with staggered concave and convex parts is attached to the take-up device. This prevents the structure from slipping and forming the protrusions, preventing damage and increasing the bulk density of the protrusions. In particular, a surface layer with high bulk density can be formed in the protrusions. The concave-convex part can be attached to both or just one of a pair of take-up devices. Furthermore, the protrusions and recesses may be formed in the same position on the front and back of the structure 1, or they may be formed at offset positions. Furthermore, the protrusions and recesses may have different patterns or sizes on the front and back.

[0082] 12A to 12E are schematic diagrams illustrating how protrusions 2 are formed by the above-described method. As shown in Fig. 12A, when the above-described protrusion formation is performed on a three-dimensional network structure on which surface layers 51 and 52 have been formed, the surface-side region inside the structure is compressed to form a central portion 53 of the protrusions, and the other regions remain as the interior portion 54 of the structure. As a result, protrusions are formed in which the central portion 53 has a bulk density higher than that of the interior portion 54, while the surface layers 51 and 52 remain. In the method of forming protrusions before the structure cools and solidifies, a thick surface layer 55 is formed at the bottom due to compression.

[0083] 12B is an explanatory diagram showing a case where the bulk density of the surface layer 51 of the three-dimensional network structure before the formation of the irregularities is made smaller than that shown in FIG. 12A . This makes it possible to make the surface layer 51 and the central portion 53 of the convex portions have the same bulk density, or to make the bulk density of the central portion 53 larger than that of the surface layer 51, thereby making the surface feel soft to the touch. By controlling the thickness and bulk density of the surface layer 51 of the network structure before the formation of the irregularities, the thickness and bulk density of the surface layer 51 of the convex portions can be controlled. The thickness and bulk density of the surface layers 51, 52 of the network structure before the formation of the irregularities can be controlled, for example, by adjusting the nozzle shape or the spacing between the nozzles.

[0084] FIG. 12C shows a case where the bulk density of the interior of the structure before the formation of the irregularities is two-layered, with the bulk density of the surface side being relatively low, thereby making the bulk density of the center 53 of the convex portion 2 relatively low. This reduces the difference in bulk density between the center 53 and the interior 54, or conversely, makes the bulk density of the interior 54 higher than that of the center 53. By making the bulk density of the interior of the structure before the formation of the irregularities multi-layered, the ratio of the bulk density of the interior 54 to the center 53 of the convex portion can also be controlled. One example of a method for achieving a two-layered bulk density before the formation of the irregularities is to adjust the spacing between the die nozzles. The hardness of the convex portion can be adjusted by adjusting the thickness and bulk density of the surface layer 51 and the bulk density of the center 53 of the convex portion. In other words, both hard and soft convex portions can be molded as desired. Convex portions with different bulk densities can be freely designed.

[0085] 12D is a diagram showing a case where the bulk density of the surface layer inside the structure before the formation of the irregularities is increased to form two layers, and the bulk density of the central portion of the protrusion 2 is formed into two layers, an upper layer 531 and a lower layer 532. In FIG. 12D, the bulk density of the upper layer 531 is higher than that of the lower layer 532, but the reverse is also possible.

[0086] 12E is a diagram showing a case where the bulk density of the back surface layer inside the structure before the formation of the irregularities is increased to form two layers, and the bulk density inside the structure is two layers, an upper layer 541 and a lower layer 542. In FIG. 12E, the bulk density of the lower layer 542 is higher than that of the upper layer 541, but the reverse is also possible. Also, instead of two layers, three or four layers are possible.

[0087] As shown in Figure 13, the three-dimensional network structure 1 can be formed by thermal processing or ultrasonic processing of a molded product, or the molded product can be a specially molded product. As shown in Figure 13A, for example, a molded product (A-1) can be subjected to thermal processing or ultrasonic processing to form an overall slope (A-2), and then further thermal processing can be performed to form a depression 6, for example, in the center (A-3). As shown in Figure 13B, a specially molded product (B-1) with raised portions 7 as holding portions on the left and right sides can be similarly compressed overall by thermal processing or ultrasonic processing (B-2), and then further thermal processing can be performed to form a depression 6, for example, in the center (B-3). In such cases, by controlling the processing conditions, it is possible to leave protrusions 2 on the surface even in the sloped or depressed areas.

[0088] Examples and comparative examples will be described below.

[0089] The body pressure distribution characteristics of the test specimens of Examples 1 to 5 and Comparative Examples 1 and 2 described below were measured with two subjects (one referred to as G (weight 85 kg) and the other as A (weight 48 kg)) sitting on them. For the measurements, an SR Soft Vision buttocks measuring device manufactured by Sumitomo Riko was used to obtain body pressure distribution measurement data with the subjects sitting on the test specimens. For details on the Sumitomo Riko SR Soft Vision measuring device, please refer to https: / / www.sumitomoriko.co.jp / product / health / SVZB922AM / . The measurement results are shown in Table 1.

[0090] Furthermore, the body pressure distribution characteristics of the test specimens of Example 1 and Comparative Examples 1 to 3 were measured with two subjects lying supine. An SR SoftVision whole-body measuring device manufactured by Sumitomo Riko Co., Ltd. was used to measure the body pressure distribution data with the subjects lying supine on the test specimens. The measurement results are shown in Table 2.

[0091] The specimen of Example 1 is a three-dimensional network structure having a thickness of 8 cm, formed from polyethylene resin and consisting of filaments with a wire diameter (diameter) of 0.7 mm, and having a plurality of protrusions arranged in a staggered pattern on the surface. The overall average bulk density is 0.090 g / cm ３ , the bulk density of the surface layer 2a is 0.161 g / cm ３The thickness is about 3 mm, and the bulk density of the flat back surface layer 11d (same as 111d in FIG. 12) is 0.189 g / cm ３ The thickness of the protrusions is 3 mm, and each protrusion has approximately the same bulk density. The average bulk density of each protrusion (including the surface layer 2 a and the central portion 2 b) is 0.10 g / cm ３ , the bulk density of the central portion 2b of the convex portion is 0.07 g / cm ３ The bulk density of the interior 11c of the structure is 0.05 g / cm ３ The number of protrusions is 1m 2 The number of particles per unit area is 500. The height of each protrusion 2 is uniform, and the height H of the protrusion is 7 mm. The width W of the protrusion is 55 mm. The average bulk density of the three-dimensional network structure body (excluding the protrusions, including the surface layer 11a, the interior 11c, and the back surface layer 11d) is 0.089 g / cm ３ is.

[0092] The specimen of Example 2 was a three-dimensional network structure having a thickness of 4.0 cm, formed of filaments having a wire diameter (diameter) of 1.0 mm and having a plurality of protrusions 2 arranged in a staggered pattern on the surface, and made of polyethylene resin. The bulk density of the surface layer 2a was 0.206 g / cm ３ The thickness is 3 mm, and the bulk density of the back surface layer 11d is 0.185 g / cm ３ The thickness is 3 mm, and the average bulk density of each protrusion 2 (including the surface layer 2 a and the central portion 2 b) is 0.055 g / cm ３ , the bulk density of the central portion 2b of the convex portion is 0.041 g / cm ３ and the bulk density of the structure interior 11c is 0.038 g / cm ３ The number of protrusions is 1m 2 The number of particles per unit area is 300. The height of the protrusions 2 is uniform, and the height H1 of the protrusions is 16 mm. The width W of the protrusions is 50 mm. The average bulk density of the three-dimensional network structure body (excluding the protrusions, including the surface layer 11a, the interior 11c, and the back surface layer 11d) is 0.046 g / cm ３ is.

[0093] The test specimen of Example 3 was prepared by placing a urethane sheet (thickness: 20 mm, bulk density: 0.02 g / cm) on the test specimen of Example 1. ３ ) are stacked.

[0094] The specimen of Example 4 is a three-dimensional network structure formed from polyethylene resin, consisting of filaments with a wire diameter (diameter) of 0.4 mm, and having a surface corrugated uneven shape with stripe-like convex portions 4 formed on the surface. The specimen has a thickness of 11 cm. The overall average bulk density is 0.032 g / cm ３ , the bulk density of the surface layer 4a is 0.056 g / cm ３ The thickness is 3 mm, and the bulk density of the back surface layer 11d is 0.080 g / cm ３ The thickness is 3 mm, and the bulk density of the central portion 4b of the streak-like convex portion is 0.027 g / cm ３ The average bulk density of each streak-like protrusion 4 (including the surface layer 4 a and the central portion 4 b) is 0.034 g / cm ３ The average bulk density of the three-dimensional network structure body (excluding the striated convex portions 4, including the surface layer 11e, the interior 11c, and the back surface layer 11d) is 0.025 g / cm ３ The height H2 of the streak-like protrusion 4 is 4 mm.

[0095] This is the fourth embodiment rotated by 90 degrees in plan view. Comparative Example 1

[0096] The specimen of Comparative Example 1 is a three-dimensional network structure having a thickness of 6 cm, which is made of a colorless polyethylene resin and has a line diameter (diameter) of 0.8 mm, and has a flat surface without irregularities. The overall average bulk density is 0.055 g / cm ３ The surface and back surfaces are provided with a surface layer and a back surface layer having a bulk density higher than that of the interior, and the surface layer has a thickness of 3 mm and a bulk density of 0.127 g / cm ３ The thickness of the back surface layer is 3 mm and the bulk density is 0.115 g / cm ３ The bulk density of the inside excluding the surface layer is 0.047 g / cm ３ is. Comparative Example 2

[0097] The test specimen of Comparative Example 2 was a urethane foam for mattresses with a thickness of 45 mm and a profiled surface with protrusions of 30 mm in height. Comparative Example 3

[0098] The test specimen of Comparative Example 3 was a urethane foam for mattresses with a smooth surface.

[0099]

[0100] As shown in Table 1, when the test specimen was used as a cushion sheet and a subject sat on it, Examples 1 to 5 performed the partial pushing and pulling functions of the uneven surface, and acupressure effects were observed, compared to the test specimen of Comparative Example 1. Compared to the test specimen of Comparative Example 2, the maximum pressure was larger, indicating that a sufficient acupressure effect could be obtained regardless of body weight. Furthermore, as can be seen from a comparison of Examples 1 to 5, the body pressure dispersion characteristics can be changed by adjusting the wire diameter of the filament, the bulk density of the convex portions, and the pattern of the convex portions 2, making it possible to meet the needs of users with different body types and preferences.

[0101]

[0102] As shown in Table 2, when the test specimens were used as mattresses and the subject was lying on his back, pressure was concentrated on the buttocks in the test specimens of Comparative Examples 1 to 3, particularly in the case of thin subject (A), but in the test specimen of Example 1, the pressure was dispersed and there was no area where pressure was concentrated. Furthermore, in Example 1, the effect of acupressure due to the unevenness was observed.

[0103] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications, substitutions, deletions, etc. can be made without departing from the technical idea of ​​the present invention, and modifications, equivalents, substitutions, deletions, etc. are also included in the technical scope of the present invention. The convex portions and streak-like convex portions do not need to be provided on the entire surface of the network structure, and can be provided only partially or in specific regions as required.

[0104] The three-dimensional network structure of the present invention is applicable to filling materials and core materials for mattresses, cushions, sofas, beds, seats, etc.

[0105] 1, 101: Three-dimensional network structure 2, 102: Convex portion 2a, 102a: Surface layer 2b, 102b: Center portion 3, 103: Bottom portion 4: Streak-like convex portion 4a: Surface layer 4b: Center portion 5: Streak-like bottom portion 11, 111: Three-dimensional network structure main body 11a, 111a: Surface layer (at bottom portion) 11c, 111c: Inside of structure 11d, 111d: Back surface layer 11e: Surface layer (at streak-like bottom portion) 51: Surface layer 52: Surface layer 53: Center portion 54: Inside of structure 55: Surface layer (bottom portion) H: Height of convex portion W: Width of convex portion

Claims

1. Overall average bulk density is 0.01 to 1.5 g / cm 3 a three-dimensional network structure used as a cushion, the three-dimensional network structure comprising a three-dimensional network structure main body and a plurality of protrusions formed on a specific surface of the three-dimensional network structure main body and protruding in a thickness direction, the plurality of protrusions being provided continuously with bottoms interposed therebetween that are lower in height than tops of the protrusions, and the average bulk density of at least one of the plurality of protrusions is 1.05 to 6 times the average bulk density of the three-dimensional network structure main body.

2. The three-dimensional network structure according to claim 1, wherein the shape of the convex portions is bowl-shaped, conical, mountain-shaped (excluding those with flat tops), or polygonal pyramid-shaped, and the plurality of convex portions are arranged continuously in a first direction with intervening bottoms that are shorter than the tops of the convex portions, and the plurality of convex portions are arranged continuously in a second direction perpendicular to the first direction with intervening bottoms that are shorter than the tops of the convex portions.

3. The three-dimensional network structure according to claim 1 or 2, characterized in that the multiple protrusions are arranged in a staggered pattern, the protrusions and the bottom each have a surface layer having a bulk density higher than the average bulk density inside the three-dimensional network structure body, and the surface layer at the bottom is thicker than the surface layer at the tops of the protrusions, or a high density portion exists continuously below the surface layer at the bottom.

4. The three-dimensional network structure according to claim 3, wherein the plurality of protrusions have the surface layer and a central portion covered by the surface layer, and the surface layer has a bulk density higher than that of the central portion.

5. The three-dimensional network structure according to claim 4, wherein the average bulk density of the central portion of at least one of the plurality of protrusions is higher than the average bulk density inside the three-dimensional network structure body.

6. The number of said protrusions is 1m 2 The three-dimensional network structure according to claim 1 or 2, wherein the number of particles per one of the three-dimensional network structures is 100 to 2500.

7. The three-dimensional mesh structure according to claim 1 or 2, which is laminated with at least one of a urethane foam, a nonwoven sheet, and another three-dimensional mesh structure, or which is laminated with a urethane foam, a nonwoven fabric, or a double raschel fabric as a cover for covering the protrusions.

8. The three-dimensional network structure according to claim 1 or 2, wherein the protrusions are arranged in a linear, staggered, or lattice pattern.

9. The three-dimensional network structure according to claim 1 or 2, wherein the height or average bulk density of the protrusions varies depending on the region of the three-dimensional network structure.

10. A three-dimensional network structure as described in claim 1 or 2, wherein the convex portions are formed on the upper and lower surfaces of the three-dimensional network structure body, and the shape, bulk density, height, or arrangement of the convex portions formed on the upper surface is different from that of the convex portions formed on the lower surface.

11. The three-dimensional network structure according to claim 1 or 2, wherein a depression or inclined portion is formed by thermal processing or ultrasonic processing on the specific surface on which the protrusions are formed, and the protrusions remain in the depression or inclined portion.

12. A three-dimensional mesh structure according to claim 1 or 2, characterized in that at least two opposing side surfaces have high density side portions having a higher density than the average bulk density of the three-dimensional mesh structure body.

13. A three-dimensional mesh structure as described in claim 1 or 2, characterized in that the three-dimensional mesh structure is provided with an elongation prevention member that prevents the three-dimensional mesh structure from elongating in the longitudinal or lateral direction, the elongation prevention member being a high-density side portion present on at least two opposing sides and having a higher density than the average bulk density of the three-dimensional mesh structure body.

14. A seat cushion, a mattress, a pillow or a chair comprising the three-dimensional mesh structure according to claim 1 or 2.

Images