Buffer material

Abstract

The present invention relates to a cushioning material. An object of the present invention is to provide a cushioning material that is difficult to deform and has high durability. The cushioning material (1) is characterized by including a first cushioning body (2) and a second cushioning body (3) disposed above the first cushioning body (2) and covering at least the upper surface of the first cushioning body (2). The first cushioning body (2) includes a three-dimensional network structure obtained by irregularly locally fusing continuous lines of a thermoplastic resin to form loops, and the second cushioning body (3) is composed of a longitudinal non-woven fabric in which fibers are oriented in the thickness direction.

Description

Technical Field

[0001] The present invention relates to a cushioning material used as a vehicle seat, a train seat, an aircraft seat, or a mattress for a vehicle, etc. Background Art

[0002] Conventionally, the vast majority of vehicle seats have used polyurethane seats that are lightweight, easy to mass-produce, and inexpensive as cushioning materials. However, in recent years, it has been recognized that the gas generated when polyurethane burns is toxic, and there has been a move to reduce the use of polyurethane around the world. Specifically, starting from 2020, the EN45545 standard of the European Union has also been adopted, and it is necessary to develop a vehicle seat with high durability, light weight, and environmental performance to replace polyurethane as soon as possible.

[0003] In addition, although the polyurethane cushioning material has excellent durability, it has problems such as poor water permeability and being prone to stuffiness.

[0004] Therefore, vehicle seats using materials to replace polyurethane have been studied. Patent Document 1 discloses a seat composed of a backrest and a seat portion formed by a cloth, a cushion layer, and a back deep-drawing shape portion. The seat is characterized in that the cushion layer is composed of a net body having an apparent density of 0.01 g / cm 3 to 0.2 g / cm 3 The net body is composed of a thermoplastic elastomer resin having a three-dimensional structure in which continuous filaments with a fineness of 100,000 denier or less are bent and brought into contact with each other, and most of the contact portions are welded, and the resin molded body is integrally joined to the net body.

[0005] Patent Document 2 discloses a vehicle seat having a seat cushion that can be disassembled and replaced and a concave portion having the same shape as the seat cushion. In the seat cushion that can be disassembled and replaced, a fiber structure body is covered with a fiber cover, and the longitudinal / transverse ratio (T / W ratio) of the fibers constituting the fiber structure body is 1.5 or more. The following is disclosed: such a seat cushion is detachably provided on a polyurethane vehicle seat having a concave portion.

[0006] Patent Document 3 discloses a vehicle seat. The seat cushion portion includes a buffer layer having a three-dimensional network structure formed by (i) a line formed of a thermoplastic elastomer resin to form a loop and joining most of the contact portions with each other, and a laminated structure of (ii) a non-woven fabric formed by joining fibers made of a thermoplastic resin. The non-woven fabric in (ii) is located on the sitting surface side. The vehicle seat is characterized in that at least the cut ends of the opposite surfaces of the three-dimensional network structure in the thickness direction are compression-bonded. In addition, the following is disclosed: The non-woven fabric is manufactured by mixing and opening thermally bonded fibers and short fibers made of a thermoplastic inelastic resin to form a three-dimensional structure, and joining and integrating most of the contact portions through a thermally bonded component.

[0007] Patent Document 4 discloses a vehicle seat having a cushioning filler. The cushioning filler is formed of a net. The net is a web formed by dispersing and mixing, as a bonding component, an elastic composite fiber composed of a thermoplastic elastomer having a melting point 40°C or more lower than the melting point of the polyester polymer constituting the short fiber and an inelastic polyester in a matrix fiber composed of an inelastic polyester-based crimped short fiber aggregate. When the total number of fibers along its length direction is set as A and the total number along the transverse direction is set as B, the condition A > 3B / 2 is satisfied. In the cushioning filler, the web is successively folded in a standing state along its length direction. At this time, in the web, there are distributed (a) flexible thermosetting points formed by mutual heat welding in a state where the elastic composite fibers cross each other, and (b) flexible thermosetting points formed by heat welding in a state where the elastic composite fibers cross the inelastic polyester-based short fibers.

[0008] Patent Document 1: Japanese Patent Laid-Open No. 8-10470

[0009] Patent Document 2: Japanese Patent Laid-Open No. 2018-193042

[0010] Patent Document 3: Japanese Patent Laid-Open No. 2003-260278

[0011] Patent Document 4: Japanese Patent Laid-Open No. 8-318066

[0012] However, in the seat of Patent Document 1, since it is composed only of a three-dimensional network structure, there is a problem of feeling the uneven touch. In addition, the deformation is large and the durability is insufficient. In addition, in the seat of Patent Document 2, especially in the area of the front end of the seat under the thigh when the user sits down, it is made of polyurethane, so there are problems of insufficient breathability and less polyurethane reduction. The seat of Patent Document 3 is a laminate of non-woven fabric and a network structure, but the non-woven fabric used as the upper layer is three-dimensionally structured by mixing and defibrating thermally bonded fibers and short fibers made of thermoplastic resin, and its anti-deformation property and durability are insufficient. In addition, since the cut ends of the upper non-woven fabric and the lower network structure are compression-bonded, there is also a problem that the product shape is limited. In the seat of Patent Document 4, since it is composed only of a fiber structure formed by fibers oriented in the thickness direction, the cushioning property and the supporting force for the buttocks and the like are insufficient. In addition, especially the shape retention of the area in front of the seat where a load is applied is low and the durability is insufficient. Summary of the Invention

[0013] Therefore, an object of the present invention is to provide a cushioning material that improves cushioning property, sitting comfort, is difficult to deform, and has high durability.

[0014] The cushioning material of the present invention is characterized by comprising: a first cushion body; and a second cushion body disposed above the first cushion body and covering at least the upper surface of the first cushion body, the first cushion body containing a three-dimensional network structure obtained by irregularly locally fusing continuous lines of a thermoplastic resin to form loops, and the second cushion body being composed of a longitudinal non-woven fabric in which fibers are oriented in the thickness direction.

[0015] Here, "fibers are oriented in the thickness direction" means that when the total number of fibers longitudinally arranged parallel to the thickness direction of the non-woven fabric is (X) and the total number of fibers transversely arranged perpendicular to the thickness direction of the non-woven fabric is (Y), X is more than Y. In addition, the longitudinal / transverse ratio (X / Y ratio) of the fibers constituting the longitudinal non-woven fabric 3 is preferably 1.5 or more, and more preferably 2.0 to 8.0.

[0016] Preferably, the cushioning material is used for a vehicle seat, the longitudinal non-woven fabric has a pleated folding structure, and a high-density portion having a higher packing density than the inside is provided in the front area of the vehicle seat.

[0017] Preferably, the 25% compression hardness of the longitudinal non-woven fabric is smaller than that of the three-dimensional network structure.

[0018] Preferably, the cushioning material is used for a vehicle seat, and the first cushion body is fitted into a groove provided on the lower surface of the second cushion body to be integrally formed.

[0019] Preferably, in the second buffer body, the region in front of the front surface of the first buffer body is a high-density portion with a higher bulk density than other regions. Thus, by maintaining the cushioning property of the front region without the three-dimensional network structure and ensuring the thickness of the high-density portion of the second buffer body, the shape retention property can also be improved.

[0020] Preferably, the cushioning material is used for a vehicle seat, and a spring receiving member is provided below the first buffer body and the second buffer body.

[0021] Preferably, the spring receiving member is composed of a three-dimensional network structure with a bulk density of 0.5 to 0.01 g / cm 3 and a thickness of 0.5 to 25 mm. The three-dimensional network structure is obtained by irregularly locally fusing continuous lines of a thermoplastic resin to form loops, and the bulk density of the three-dimensional network structure constituting the spring receiving member is higher than that of the three-dimensional network structure included in the first buffer body.

[0022] Preferably, the cushioning material is used for a vehicle seat, and the three-dimensional network structure included in the first buffer body has a density structure in which sparse portions and dense portions extending in the width direction of the vehicle seat are repeatedly arranged in the front-rear direction, and the dense portions are provided at the middle portion in the front-rear direction of the vehicle seat.

[0023] Preferably, the first buffer body is composed of multiple layers, including a three-dimensional network structure as the upper layer and a second longitudinally-oriented non-woven fabric as the layer located below the upper layer. The bulk density of the second longitudinally-oriented non-woven fabric is higher than that of the longitudinally-oriented non-woven fabric constituting the second buffer body.

[0024] Preferably, the first buffer body is composed of multiple layers, including a three-dimensional network structure as the upper layer and a non-woven fabric with fibers oriented transversely as the layer located below the upper layer.

[0025] Preferably, the first buffer body is composed of multiple layers, including a three-dimensional network structure as the upper layer and a polyurethane foam as the layer located below the upper layer.

[0026] Preferably, the cushioning material is used for a mattress, and the second buffer body has a density structure in which sparse portions and dense portions extending in the width direction are repeatedly arranged in the length direction of the mattress, and the dense portions are provided at the middle portion of the mattress.

[0027] Preferably, the cushioning material is used for a mattress, and the first buffer body includes a surface layer, an upper layer, and a base layer. The bulk density of the surface layer is higher than that of the upper layer and the base layer, and the bulk density of the base layer is higher than that of the upper layer.

[0028] Preferably, the second buffer body is included in a covering cover that covers at least the upper surface of the first buffer body.

[0029] In the present invention, in the cushioning material, a longitudinal non-woven fabric is disposed in a portion located on the hip and thigh sides when the user is seated, and a three-dimensional net structure body is provided below it. Therefore, even when used for a long time, deformation of the upper surface and the front area of the seat can be suppressed, and the ventilation of the entire seat can be improved. In addition, by virtue of the elasticity of the three-dimensional net structure body itself, the supporting force of the hip and the like is increased, and fatigue is not easily caused. Further, when the cushioning material is used for a vehicle seat, by forming a high-density portion in the front area of the longitudinal non-woven fabric, the shape retention and durability can be improved, and the seating comfort can also be improved. Moreover, the amount of polyurethane used can be reduced, and the burden on the environment can also be alleviated. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view of the buffer body (vehicle seat) of the first embodiment.

[0031] Figure 2 is a cross-sectional view taken along the line X-X of the buffer body (vehicle seat) of the first embodiment.

[0032] Figure 3 is a cross-sectional view taken along the line X-X of the buffer body (vehicle seat) of the second embodiment.

[0033] Figure 4 is a cross-sectional view taken along the line X-X of the buffer body (vehicle seat) of the third embodiment.

[0034] Figure 5 is a longitudinal sectional view of the buffer body (mattress) of the fourth embodiment.

[0035] Figure 6 is a longitudinal sectional view of a modified example of the buffer body (mattress) of the fourth embodiment.

[0036] Figure 7 is a view illustrating the usage state of the buffer body (mattress) of the fourth embodiment.

[0037] Figure 8 is a longitudinal sectional view of the buffer body (mattress) of the fifth embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Refer to Figures 1 to 2A vehicle seat 1 (buffer material) according to a first embodiment of the present invention will be described. The vehicle seat 1 includes: a three-dimensional mesh structure 2 as a first buffer; a longitudinal non-woven fabric 3 as a second buffer disposed above the first buffer; and a spring receiving member 4. The longitudinal non-woven fabric 3 has a shape in which the thickness becomes thinner in the front region. In a groove portion 32 formed on the lower surface of the longitudinal non-woven fabric 3, the three-dimensional mesh structure 2 having the same shape as the groove portion 32 is fitted, and the spring receiving member 4 is disposed so as to abut against the lower surfaces of the three-dimensional mesh structure 2 and the longitudinal non-woven fabric 3, and the whole is covered with a covering (not shown) made of cotton cloth, non-woven fabric, etc.

[0039] The three-dimensional mesh structure 2 has a substantially rectangular parallelepiped shape, and the groove portion 32 has an inner shape substantially the same as its outer shape. In a state where the three-dimensional mesh structure 2 is fitted into the groove portion 32 of the longitudinal non-woven fabric 3, the entire front and rear sides, left and right sides, and upper surface of the three-dimensional mesh structure 2 are in contact with and covered by the longitudinal non-woven fabric 3, and the lower surfaces of the three-dimensional mesh structure 2 and the longitudinal non-woven fabric 3 form one surface. The thickness of the longitudinal non-woven fabric 3 is preferably 5 to 150 mm, and the thickness of the three-dimensional mesh structure 2 is preferably 5 to 140 mm.

[0040] The longitudinal non-woven fabric 3 includes short fibers and thermally adhesive fibers, and the fibers are longitudinally oriented in the thickness direction of the longitudinal non-woven fabric 3. "The fibers are longitudinally arranged in the thickness direction" means that when the total number of fibers longitudinally arranged parallel to the thickness direction of the non-woven fabric is (X) and the total number of fibers transversely arranged perpendicular to the thickness direction of the non-woven fabric is (Y), X is greater than Y. In addition, the longitudinal / transverse ratio (X / Y ratio) of the fibers constituting the longitudinal non-woven fabric 3 is preferably 1.5 or more, and more preferably 2.0 to 8.0. For the ratio of the total number of longitudinal fibers (X) to the total number of transverse fibers (Y), the longitudinal non-woven fabric 3 is cut in the thickness direction, and on its cross-section, the number of fibers arranged parallel (0° to 45°) to the thickness direction and the number of fibers arranged perpendicular (45 to 90°) to the thickness direction are observed through a microscope, and thus their ratio can be calculated.

[0041] In order to obtain such a longitudinal nonwoven fabric 3, a conventionally well-known method can be adopted. However, the following method is exemplified: for example, short fibers and heat-bondable short fibers are mixed and carded, and a uniform web is formed by a roller carding machine. Then, a conventionally well-known heat treatment machine is used to fold the web into a pleated shape, and in the folded state, heat treatment is performed to form fixing points based on hot melt bonding. Generally, most of the fibers constituting the web are arranged in the plane direction of the web. Therefore, by continuously folding it into a pleated shape for lamination, most of the fibers can be arranged in the thickness direction. More specifically, as a manufacturing method of the longitudinal nonwoven fabric 3, it can be manufactured by folding it into a zigzag shape by a struto device (registered trademark, a nonwoven fabric manufacturing device described in the specification of European Patent Application Publication No. 0350627), or an air-laying machine (for example, produced by FEILER Corporation, V21 / R-K12, V21 / K12), etc., and then performing compression and heat treatment. The fiber length of the short fibers used for the longitudinal nonwoven fabric 3 is preferably in the range of 30 to 100 mm. In addition, in addition to the pleated structure, the longitudinal nonwoven fabric 3 may also be a fiber structure obtained by repeatedly performing the process of stacking short fibers in a rectangular shape.

[0042] The longitudinal nonwoven fabric 3 of the present embodiment is a structure having a structure in which a nonwoven fabric web is folded into a pleated form, and the folding direction is the front-rear direction of the vehicle seat 1.

[0043] As the short fibers constituting the longitudinal nonwoven fabric 3, natural fibers such as cotton and wool, inorganic fibers such as carbon fibers, synthetic fibers such as polyolefins and polyesters, etc. can be used. As the heat-bondable fiber, a synthetic fiber having a melting point 40 degrees or more lower than the above-mentioned short fibers is preferred. The bulk density of the longitudinal nonwoven fabric 3 is preferably 0.005 to 0.50 g / cm 3 。

[0044] The longitudinal nonwoven fabric 3 has a density structure having a sparse portion and a dense portion in the front-rear direction. Specifically, in the region on the front side of the seat, a high-density portion 31 having a higher bulk density than other places is provided. The bulk density of the high-density portion 31 is preferably 0.01 to 0.50 g / cm 3. In the present embodiment, a region in front of the front side surface of the three-dimensional network structure 2 is defined as a high-density portion 31, and there is no high-density portion 31 directly above the three-dimensional network structure 2. The high-density portion 31 extends in the width direction of the vehicle seat 1. The density of the longitudinal non-woven fabric 3 can be varied, for example, by changing the folding density of the fiber sheet during manufacturing. Since the high-density portion 31 is provided, the shape retention of the front region, which is particularly likely to be loaded and whose shape is likely to collapse, can be improved, and the cushioning property can also be improved. The high-density portion 31 is not limited to the front. From the perspective of shape retention, it is also preferable to provide the high-density portion 31 on the left and right side surfaces and the rear side surface of the longitudinal non-woven fabric 3. In addition, a density structure in which a dense portion with a high packing density and a sparse portion with a low packing density repeatedly appear may be provided in one or a combination of the thickness direction, the front-rear direction, and the left-right direction.

[0045] The entire seating surface of the vehicle seat 1 is composed of the longitudinal non-woven fabric 3, so the air permeability is good, and even if the user sits for a long time, there is no need to worry about stuffiness. In addition, the longitudinal non-woven fabric 3 is elastic compared with a planar non-woven fabric in which the fibers are arranged horizontally, and the sitting feeling is good and relaxed. In addition, the longitudinal non-woven fabric 3 has particularly strong tolerance to "deformation" caused by a load from above. Even when the user is sitting, the portion where the buttocks and the rear part of the thigh of the leg, which are the parts where the most load is applied, come into contact can maintain durability. And for the longitudinal non-woven fabric 3, the longitudinally oriented fibers are perpendicular to the pressure-receiving surface. Therefore, when the user sits and applies a load, it deforms in units of points and deforms along the user's body. Therefore, the body pressure dispersion is excellent, and it is not easy to get tired even when sitting for a long time.

[0046] The three-dimensional network structure 2 is a structure formed by irregularly partially fusing continuous lines made of a thermoplastic resin with a wire diameter (diameter) of 0.3 mm to 1.5 mm to form loops. The packing density (apparent density) is an important factor determining soft high resilience and can be designed as needed. It is preferably 0.025 g / cm 3 ~0.2 g / cm 3 , more preferably 0.04 g / cm 3 ~0.09 g / cm 3 . If the packing density is less than 0.025 g / cm 3 , the shape cannot be maintained. If it exceeds 0.20 g / cm 3 , it is not suitable as a vehicle seat.

[0047] As the raw material of the three-dimensional network structure 2, that is, the thermoplastic resin, it preferably includes polyethylene-based thermoplastic resins, polypropylene-based thermoplastic resins, polyester-based thermoplastic elastomers, polypropylene-based thermoplastic elastomers, mixtures of polyethylene-based thermoplastic resins and polyethylene-based thermoplastic elastomers, PVC, polyurethane elastomers, nylon-based elastomers, polystyrene elastomers, etc.

[0048] For the detailed manufacturing method of the three-dimensional network structure 2 used in the present invention, please refer to the gazettes of the patent applicants such as Japanese Patent No. 4350286 and U.S. Patent No. 7625629.

[0049] The three-dimensional network structure 2 has the following density structure: a dense part 21 having a relatively high packing density δ1 and a sparse part 22 having a relatively low packing density δ2 are alternately repeated in the front-rear direction of the seat. In the present embodiment, a dense part 21 extending in the width direction is formed in the middle part in the front-rear direction of the seat, and sparse parts 22 are formed in front of and behind the dense part 21. In particular, the packing density of the dense part 21 is preferably 0.03 to 0.10 g / cm 3 , and the packing density of the sparse part is preferably 0.01 to 0.08 g / cm 3 . In particular, since the dense part 21 is provided in the area where the load is applied, the cushioning property, durability, and sitting comfort are improved. This density structure can be formed by the following method: taking the extrusion direction during the manufacture of the three-dimensional network structure 2 as the front-rear direction of the seat and making the speed of the roller or the track variable.

[0050] As a modification, the three-dimensional network structure 2 may further have a density structure in the thickness direction and the left-right direction. In addition, for example, by four-side forming, a surface layer having a higher packing density than the inside may be provided on the upper surface, the lower surface, and the left and right side surfaces.

[0051] Next, the spring receiving member 4 will be described. The spring receiving member 4 functions as follows: preventing the rod-shaped spring disposed in the seat frame below the vehicle seat 1 from biting into the vehicle seat 1.

[0052] In the present embodiment, the spring receiving member 4 is a three-dimensional network structure obtained by irregularly partially fusing continuous lines of a thermoplastic resin having a wire diameter (diameter) of 0.3 mm to 1.5 mm to form a ring, but it is a buffer having a packing density δ3 higher than the packing densities δ1 and δ2 of the three-dimensional network structure 2 as the first buffer material and being harder. For the spring receiving member 4, the packing density is preferably 0.5 to 0.01 g / cm 3 , and the thickness is 0.5 to 25 mm. The hardness of the spring receiving member 4 can be adjusted by changing the fineness, packing density, raw material, and structure.

[0053] As the raw material of the spring receiving member 4, i.e., the thermoplastic resin, it preferably includes polyethylene-based thermoplastic resin, polypropylene-based thermoplastic resin, polyester-based thermoplastic elastomer, polypropylene-based thermoplastic elastomer, a mixture of polyethylene-based thermoplastic resin and polyethylene-based thermoplastic elastomer, PVC, polyurethane elastomer, nylon-based elastomer, polystyrene elastomer, etc.

[0054] For the spring receiving member 4, in the tensile test described later, the maximum load (maximum endurance) in the extrusion direction during manufacturing is 9.8 to 294.2 N, preferably 19.6 to 294.2 N. If the maximum load in the tensile test is less than 19.6 N, there is a possibility that the fusion between fibers during compression will peel off. The maximum load in the above extrusion direction is affected by fineness, bulk density, raw material, and structure.

[0055] The above tensile test is carried out in the following manner.

[0056] A structure obtained by cutting a product of the three-dimensional network structure into 10 cm (length: extrusion direction) × 10 cm (width) is used as a test piece. The upper end of the test piece is fixed, a hook with a diameter of 5 mm and an R of 20 is hung 4 cm above the lower end at the center in the width direction of the test piece, and it is pulled downward to measure the maximum load.

[0057] The detailed manufacturing method of the spring receiving member 4 used in the present invention is basically the same as that of the three-dimensional network structure 2.

[0058] Preferably, the left and right width c of the three-dimensional network structure 2 is 100 to 2000 mm, and the depth b is 200 to 700 mm. Preferably, the width a of the longitudinal non-woven fabric 3 is 300 to 2000 mm, and the depth d is 300 to 800 mm.

[0059] In addition to the above three-dimensional network structure, the spring receiving member 4 can also be made of felt, non-woven fabric, etc.

[0060] In the present embodiment, the vehicle seat 1 is formed in such a way that a groove portion 32 is formed on the inner surface of the longitudinal non-woven fabric 3. By inserting the three-dimensional network structure 2 into the groove portion 32, the spring receiving member 4 is laminated and covered with a covering cover (not shown). The three-dimensional network structure 2, the longitudinal non-woven fabric 3, and the spring receiving member 4 can be covered by the covering cover in a state of being fitted and laminated without adhesion, but they can also be joined to each other by adhesives such as heat-based fusion, hook-and-loop fasteners, hot melt adhesives, etc.

[0061] The three-dimensional network structure 2 and the longitudinal non-woven fabric 3 are both preferably such that the limiting oxygen index (L.O.I value) is 28 or more. In addition, the covering is preferably made of flame-retardant fibers, and when used for a seat for a tram, it is preferably such that the limiting oxygen index (L.O.I value) is 28 or more. As the flame-retardant fibers, known fibers such as carbon fibers and refractory fibers are used.

[0062] In the present invention, the longitudinal non-woven fabric 3 is disposed on the surface side (human body side) to improve anti-deformation property, durability, and touch, and by disposing the three-dimensional network structure 2 on its lower surface, the cushioning property and sitting comfort are thereby improved.

[0063] The 25% compression hardness of the dense portion 21 and the sparse portion 22 of the three-dimensional network structure 2 is higher than that of the longitudinal non-woven fabric 3. The 25% compression hardness is measured according to JIS K6400-2. Specifically, it is preferably such that the 25% compression hardness of the dense portion 21 of the three-dimensional network structure is 80 to 180 N, the 25% compression hardness of the sparse portion 22 is 40 to 130 N, and the 25% compression hardness of the longitudinal non-woven fabric 3 (excluding the high-density portion 31) is 25 to 100 N. By making the hardness of the longitudinal non-woven fabric 3 100 N or less, a soft touch when sitting can be obtained, and by making the hardness 25 N or more, an excessive sinking can be prevented. In the present embodiment, since the longitudinal non-woven fabric 3 and the three-dimensional network structure 2 are made of a thermoplastic elastomer resin, most of the vibration applied from the outside is absorbed and attenuated by the vibration absorption function of the thermoplastic elastomer resin, and thus it functions as a vibration cut-off layer.

[0064] Next, with reference to Figure 3 (a) to (c), the vehicle seat 101 (cushioning material) of the second embodiment of the present invention will be described. The vehicle seat 101 has substantially the same structure as the vehicle seat 1, so for the general description, the drawings and descriptions of the first embodiment are cited, and the differences will be described. The reference numerals attached to the respective elements are the corresponding numbers of the first embodiment and are set to three-digit numbers in the 100s range.

[0065] In the first embodiment, the first cushioning body is composed of a single layer of a three-dimensional network structure, but in the second embodiment, the first cushioning body is composed of a double layer of an upper layer 121 and a lower layer 122. The upper layer 121 is composed of a three-dimensional network structure, and as the lower layer 122, a non-woven fabric in which fibers are oriented in the lateral (plane) direction, a longitudinal non-woven fabric, a foamed polyurethane, and other cushioning materials can be used. By further providing a lower layer and an intermediate layer, it can also be formed into multiple layers such as three layers and four layers. In each of the following examples of the lower layer 122, it is also preferable to have a density structure in the thickness direction, front-rear direction, and left-right direction.

[0066] In Figure 3In (a), the upper layer 121 constituting the first buffer body 102 is formed of a three-dimensional network structure, and the lower layer 122 is a non-woven fabric in which fibers are oriented in the lateral direction (plane direction). Thereby, durability can be improved.

[0067] In Figure 3 (b), the upper layer 121 constituting the first buffer body 102 is formed of a three-dimensional network structure, and the lower layer 122 is formed of a longitudinal non-woven fabric. The longitudinal non-woven fabric used for the lower layer 122 is a non-woven fabric having a higher bulk density and being harder than the longitudinal non-woven fabric 103 used as the second buffer body. The longitudinal non-woven fabric 103 preferably has a 25% compression hardness of 25 to 100 N and a density of 25 to 80 g / cm 3 , and the lower layer 122 preferably has a 25% compression hardness of 40 to 140 N and a density of 40 to 100 g / cm 3 . Thereby, elasticity is improved and the sitting comfort is also improved. In addition, the 25% compression hardness is measured according to JIS K6400-2. The 25% compression hardness can be adjusted by changing the material, bulk density, and fineness of the non-woven fabric.

[0068] In Figure 3 (c), the upper layer 121 is a three-dimensional network structure, and the lower layer 122 is a polyurethane foam. By using the polyurethane foam, higher durability is obtained.

[0069] Next, the vehicle seat 201 according to the third embodiment of the present invention will be described with reference to Figure 4 . The vehicle seat 201 has substantially the same structure as the vehicle seat 1. Therefore, for the general description, the drawings and descriptions of the first embodiment are cited, and the differences will be described. The reference numerals of the respective elements are set to the 200-series numbers corresponding to those of the first embodiment.

[0070] In the vehicle seat of the first embodiment, the three-dimensional network structure 2 serving as the first buffer body is fitted into the groove portion 32 on the inner surface of the longitudinal non-woven fabric 3 serving as the second buffer body. However, in the vehicle seat of the second embodiment, it is configured such that a longitudinal non-woven fabric 203 having a substantially flat lower surface is laminated on the upper layer of the three-dimensional network structure 202. The longitudinal non-woven fabric 203 and the spring receiving member 204 are covered with a covering (not shown). A high-density portion 231 is formed in a portion having a relatively thin thickness in the front region of the longitudinal non-woven fabric 203, and a density structure having a sparse portion 222 and a dense portion 221 in the front-rear direction is formed in the three-dimensional network structure 202. The dense portion 221 is formed in the middle portion.

[0071] Next, the mattress 301 as a cushioning material according to the fourth embodiment of the present invention will be described with reference to Figures 5 to 7 .

[0072] In the first to third embodiments, the cushioning material is used as a vehicle seat, but in this embodiment, it is used as a mattress. The mattress 301 has substantially the same structure as the vehicle seat 1. Therefore, for general explanations, the drawings and descriptions of the first embodiment are cited, and the differences are explained. The reference numerals assigned to the respective elements are the corresponding numbers of the first embodiment and are numbers in the 300 series.

[0073] As Figure 7 shown, the mattress 301 is, for example, a mattress used for a bed provided at the rear in the cab of the truck 8. As is well known, the mattress 301 can be used by a driver or the like for a short nap in the vehicle, or by a co-driver sitting at the rear between the seats 81.

[0074] Figure 5 is a longitudinal sectional view of the mattress 301. The mattress 301 includes a first cushioning body formed of a three-dimensional network structure body 302 and a second cushioning body formed of a longitudinal non-woven fabric 303 that covers the upper surface of the three-dimensional network structure body 302. The overall bulk density of the longitudinal non-woven fabric 303 as the second cushioning body is 0.005 to 0.50 g / cm 3 , and has a density structure in which sparse portions and dense portions extending in the width direction in the length direction are repeatedly provided in the front-rear direction. The central portion becomes a high-density portion 331, and medium-density portions 333 are provided on both sides thereof.

[0075] The three-dimensional network structure body 302 as the first cushioning body also has a density structure in which sparse portions and dense portions extending in the width direction in the length direction are repeatedly provided in the front-rear direction. The central portion becomes a dense portion 321, and the portions on both sides thereof become sparse portions 322. The overall bulk density of the first cushioning body is 0.03 to 0.80 g / cm 3 . The dense portion 321 exists in contact with the lower surface of the high-density portion 331. As described above, a co-driver sometimes sits in the center of the mattress 301. However, since the high-density portion 331 is provided at the central portion in the length direction, the durability is improved. In addition, it has the advantage that it is very comfortable for a driver or the like to lie on when sleeping. The entire laminate of the three-dimensional network structure body 302 and the longitudinal non-woven fabric 303, or its upper surface and side surfaces, are covered with a covering (not shown) made of cotton cloth, non-woven fabric, or the like. The laminate of the three-dimensional network structure body 302 and the longitudinal non-woven fabric 303 can be covered with the covering in a state where they are laminated without being bonded to each other, or they can be joined to each other by adhesives such as heat fusion, hook-and-loop fasteners, hot melt adhesives, etc.

[0076] Figure 6is a longitudinal sectional view showing a modified example of the length direction of the mattress 301. The mattress 301 includes a first cushioning body composed of a three-dimensional mesh structure 302 and a second cushioning body composed of a longitudinal non-woven fabric 303. The three-dimensional mesh structure 302 has a surface layer 323, an upper layer 324, and a base layer 325 starting from the surface. The surface layer 323 is a thin high-density layer of about 2 mm, and the bulk density is 0.045 to 0.80 g / cm 3 . The bulk density of the base layer 325 is lower than that of the surface layer 323, and the bulk density is 0.040 to 0.70 g / cm 3 . The bulk density of the upper layer 324 is lower than that of the surface layer 323 and the base layer 325, and the bulk density is 0.040 to 0.70 g / cm 3 .

[0077] Next, refer to Figure 8 to describe the mattress 401 as a cushioning material according to the fifth embodiment of the present invention. The mattress 401 has substantially the same structure as the mattress 301. Therefore, for general descriptions, the drawings and descriptions of the fourth embodiment are cited, and the differences are described. The reference numerals assigned to each element are the numbers in the 400-number range corresponding to the reference numerals in the fourth embodiment. In the fourth embodiment, the laminate of the three-dimensional mesh structure 302 and the longitudinal non-woven fabric 303 is covered with a covering. In contrast, in the present embodiment, the longitudinal non-woven fabric 403 is included in the covering 405 that covers the three-dimensional mesh structure 402. The longitudinal non-woven fabric 403 is thinner than the three-dimensional mesh structure 402. It is preferable to place the longitudinal non-woven fabric 403 in the covering 405 and fix it by quilting.

[0078] In the present embodiment, the longitudinal non-woven fabric 403 and the entire three-dimensional mesh structure 402 have a uniform bulk density. However, as in the fourth embodiment, it is preferable to have a high-density portion at the central portion in the length direction, or the three-dimensional mesh structure 402 has a surface layer, an upper layer, and a base layer with different bulk densities in the thickness direction. According to the present embodiment, since it is only necessary to attach the covering to the three-dimensional mesh structure 402, there are advantages such as easy manufacturing. In addition, in the vehicle seats of the first to third embodiments, it is also preferable to fix the longitudinal non-woven fabric in the covering as in the present embodiment.

[0079] Explanation of reference numerals

[0080] 1, 101, 201... vehicle seats; 301, 401… mattresses; 2, 202, 302, 402... three-dimensional mesh structures (first buffer bodies); 102... first buffer body; 21, 221, 321… dense parts; 22, 222, 322… sparse parts; 3, 103, 203, 303, 403... longitudinal non-woven fabrics (second buffer bodies); 31, 231, 331... high-density parts; 333… medium-density part; 323… surface layer; 324… upper layer; 325… base layer; 32... groove part; 4, 104, 204... spring receiving members; 121... upper layer of the first buffer body; 122... lower layer of the first buffer body; 8… trucks.

Claims

1. A buffer material, characterized in that, Comprising: A first buffer body; and A second buffer body, disposed above the first buffer body and covering at least the upper surface of the first buffer body, The first buffer body includes a three-dimensional network structure obtained by irregularly locally fusing continuous lines of a thermoplastic resin to form loops, The second buffer body is composed of a longitudinal non-woven fabric in which fibers are oriented in the thickness direction, The buffer material is for a vehicle seat, The longitudinal non-woven fabric has a pleated folding structure and has a high-density portion with a higher packing density than the interior in the front region of the vehicle seat.

2. The buffer material according to claim 1, wherein: The first buffer body is integrally formed by fitting into a groove portion provided on the lower surface of the second buffer body, In the second buffer body, the region in front of the front surface of the first buffer body is a high-density portion with a higher packing density than other regions.

3. The buffer material according to claim 1, wherein: A spring receiving member is provided below the first buffer body and the second buffer body, The spring receiving member is composed of a three-dimensional network structure having a bulk density of 0.5 to 0.01 g / cm 3 and a thickness of 0.5 to 25 mm. The three-dimensional network structure is obtained by irregularly locally fusing continuous lines of a thermoplastic resin to form loops. The packing density of the three-dimensional network structure constituting the spring receiving member is higher than the packing density of the three-dimensional network structure included in the first buffer body.

4. The buffer material according to claim 1, wherein: The three-dimensional network structure included in the first buffer body has a density structure in which sparse portions and dense portions extending in the width direction of the vehicle seat are repeatedly arranged in the front-rear direction, and the dense portions are provided in the middle portion in the front-rear direction of the vehicle seat.

5. The buffer material according to claim 1, wherein: The first buffer body is composed of multiple layers, including a three-dimensional network structure as the upper layer and a second longitudinal non-woven fabric as the layer located below the upper layer, and the packing density of the second longitudinal non-woven fabric is higher than that of the longitudinal non-woven fabric constituting the second buffer body.

6. The buffer material according to claim 1, wherein: The first buffer body is composed of multiple layers, including a three-dimensional network structure as the upper layer and a non-woven fabric in which fibers are oriented horizontally as the layer located below the upper layer.

7. The buffer material according to claim 1, wherein: The first buffer body is composed of multiple layers, including a three-dimensional network structure as the upper layer and a polyurethane foam as the layer located below the upper layer.

8. The buffer material according to any one of claims 1 to 7, wherein: The 25% compression hardness of the longitudinal non-woven fabric is smaller than that of the three-dimensional network structure.

9. The buffer material according to any one of claims 1 to 7, wherein: The second buffer body is included in a covering that covers at least the upper surface of the first buffer body.

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