Cushioning materials and seat cushions

Abstract

We provide highly durable cushioning materials and seat cushions. [Solution] The cushioning material comprises a first chip urethane layer having an uneven surface, and a second chip urethane layer disposed on the uneven surface of the first chip urethane layer. The second chip urethane layer is bonded to the first chip urethane layer with an adhesive.

Description

[Technical Field]

[0001] This disclosure relates to cushioning materials and seat cushions. [Background technology]

[0002] Patent Document 1 discloses a folding chair in which the cushion seat and cushion back are formed from a laminate of a lower cushion made of medium-hardness chip urethane and an upper cushion made of soft polyurethane foam. The folding chair further consists of a 1-3 cm thick foamed polyethylene sheet interposed between the entire surface of the seat frame and the cushion seat.

[0003] Patent Document 2 discloses a chair body in which the seat and backrest are integrally molded from urethane foam. A sheet of melted polyurethane foam is provided to cover the front surface of this chair body, and a honeycomb mesh fabric is provided on the parts of the seat and backrest covered with this melted polyurethane foam sheet that come into contact with the user's body.

[0004] Patent Document 3 discloses a seat chair in which a frame and a middle layer material are embedded in chip material to which adhesive has been applied within a lower mold. The lower and upper molds are closed, and while compressing each material made of soft polyurethane foam, water vapor is supplied into the mold to cure the adhesive, thereby joining the chip materials together to form a laminated layer. The laminated layer is then joined to the upper layer material, middle layer material and lower layer material to integrate them and manufacture the seat chair. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Utility Model Registration No. 3204794 Gazette [Patent Document 2] Japanese Patent Publication No. 2004-236987 [Patent Document 3] Japanese Patent Publication No. 2016-54932 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] This disclosure provides a cushioning material and a seat chair with excellent durability. [Means for solving the problem]

[0007] A cushioning material according to one aspect of the present disclosure is characterized by comprising a first chip urethane layer having an uneven surface, and a second chip urethane layer disposed on the uneven surface of the first chip urethane layer.

[0008] A chair according to another aspect of the present disclosure is characterized by comprising the cushioning material. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide cushioning materials and seating chairs with excellent durability. [Brief explanation of the drawing]

[0010] [Figure 1] Overall perspective view of a seat chair 10 according to an embodiment of this disclosure [Figure 2] A side view of the exploded configuration of the upright seat chair 10 according to the embodiment of this disclosure. [Figure 3] An exploded view of the chair 10 according to the present disclosure, with the backrest tilted backward, as seen from the side. [Figure 4] Cross-sectional view (A-A in Figure 3) of the seat chair 10 according to the embodiment of this disclosure [Figure 5] A side view of the seat cushion material according to the embodiment of this disclosure. [Figure 6] Schematic cross-sectional view of a compression test of the first chip urethane layer having an uneven surface. [Figure 7] (Enlarged) schematic diagram of a cross-section of chip urethane (ribboned foam) [Figure 8](Enlarged) schematic view of the portion where the first chip urethane layer 81 and the second chip urethane layer 82 having concavo-convex surfaces according to an embodiment of the present disclosure are adhered, as viewed from the side

Mode for Carrying Out the Invention

[0011] <Overall Structure>

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is an overall perspective view of a folding chair 10 according to an embodiment of the present invention.

[0013] The folding chair 10 is a reclining chair that is installed on a floor or tatami mat, and a backrest portion 15 is provided on the rear side of the seat portion 13 so as to be rotatable (tiltable) in multiple stages.

[0014] As shown in FIG. 1, the chair 10 includes a seat portion 13 on which a user sits, a backrest portion 15 connected to the rear end of the seat portion 13 to support the user's back, and a head portion 17 to support the user's head. The chair according to the embodiment of this invention can also be opened by tilting the backrest portion 15 backward, and can be folded by tilting it forward and backward.

[0015] Also, FIGS. 2 and 3 are exploded configuration diagrams of the chair 10 according to the embodiment of the present invention in a standing state and a state where the backrest is tilted backward, as viewed from the side. As shown in FIGS. 2 and 3, the chair 10 is configured such that the backrest portion 15 is angle-adjustable with respect to the seat portion 13.

[0016] <000​​​​The frame structure comprises a seat frame 23 which forms the skeleton of the seat 13, a backrest frame 25 which forms the skeleton of the backrest 15, and a pair of left and right backrest angle adjusters 24. The backrest angle adjusters 24 connect the seat frame 23 and the backrest frame 25 in a manner that allows for multi-stage rotation.

[0018] Furthermore, the headrest frame 27, which forms the upper skeleton of the backrest 15, is connected to the tip of the backrest frame 25 via a pair of left and right headrest angle adjusters 26. The headrest angle adjusters 26 are capable of multi-stage rotation. The seat frame 23, backrest frame 25, and headrest frame 27 together are called the main body frame 21. The main body frame 21 forms the frame structure that supports the seat 13, backrest 15, and headrest 17.

[0019] The shape of each frame in the frame structure is arbitrary, as long as it functions as the framework of the folding chair 10. Various metal pipes, such as stainless steel, iron, and aluminum alloy, can be used as materials for the seat frame 23, backrest frame 25, and headrest frame 27. The metal pipes forming the frame structure are equipped with multiple bands, such as polypropylene bands. The multiple bands are wrapped around the parallel metal pipes to connect them.

[0020] The backrest angle adjuster 24 and the headrest angle adjuster 26 are structures that allow the corresponding backrest 15 and headrest 17 to rotate in multiple stages (two or more stages), and can employ, for example, a ratchet type. "Multi-stage rotation" means that the corresponding backrest 15, etc., rotates intermittently in, for example, 2 to 30 stages around a horizontal axis.

[0021] Furthermore, the chair 10 is equipped with a protective sheet between the backrest angle adjuster 24 and the elastic porous material or cushioning material. The elastic porous material or cushioning material is protected by protective sheets placed on the upper and lower surfaces of the backrest angle adjuster 24 to prevent tearing due to load.

[0022] The folding chair 10 can be adjusted using the backrest angle adjuster 24 to change between an upright position (see Figures 1 and 2) in which the backrest 15 stands upright from the rear edge of the seat 13, and a reclined position (see Figure 3). The reclined position (see Figure 3) is a position in which the backrest 15 is reclined so as to lie along the floor surface, making the seat 13 and backrest 15 approximately horizontal.

[0023] The seat portion 13 of the folding chair 10 comprises a seat frame 23 and a seat cushion material 31. The backrest portion 15 of the folding chair 10 comprises a backrest frame 25 and a backrest cushion material 51. The head portion 17 of the folding chair 10 comprises a headrest frame 27 and a headrest cushion material 71. The cushion material of the chair 10 includes the seat cushion material 31, the backrest cushion material 51, and the headrest cushion material 71.

[0024] The folding chair 10 includes a bag-shaped cover material 96 that covers the seat 13, backrest 15, and headrest 17. The cover material 96 covers the top and bottom surfaces of the seat cushion material 31, the top and bottom surfaces of the backrest cushion material 51, and the top and bottom surfaces of the headrest cushion material 71.

[0025] The cover material 96 is a bag-like body constructed by joining together cloth, leather, or other flexible sheet-like materials by sewing or adhesive. The cover material 96 has an opening, which allows it to be attached to or removed from the seat cushion material 31, backrest cushion material 51, and head cushion material 71 so as to cover their outer perimeters.

[0026] The material of the cover material 96 is arbitrary. For example, the material of the cover material 96 can be fabric materials made from processed fibers such as various woven fabrics, knitted fabrics, and nonwoven fabrics. In addition, the material of the cover material 96 may be knitted material, Dalian fabric, leather (genuine leather, synthetic leather), or synthetic resin sheet. The cover material 96 may be a single layer or a multi-layered structure made by layering the same material or different materials. <Cushioning material>

[0027] The cushioning materials used in the seat 13, backrest 15, and headrest 17 will be described below.

[0028] As shown in Figures 2-4, the seat 13 comprises a seat frame 23, a seat cushion material 31, a lower elastic porous body 80, an upper elastic porous body 84, and a band (not shown), etc. The seat cushion material 31 is positioned above the seat frame 23 and the band wrapped around the metal pipe of the seat frame 23. The seat cushion material 31, the lower elastic porous body 80, and the upper elastic porous body 84 are arranged to surround the seat frame 23 (and band) on all sides (top, bottom, left, and right). The lower elastic porous body 80 covers the lower surface of the seat cushion material 31 and the seat frame 23, and the upper elastic porous body 84 covers the upper surface of the seat cushion material 31. The lower elastic porous body 80 and the upper elastic porous body 84 are bonded together at both ends via an adhesive layer 86B, forming a bag shape.

[0029] The backrest 15 has the same configuration as the seat 13. As shown in Figure 3, the backrest 15 comprises a backrest frame 25, a backrest cushion material 51, a lower elastic porous body 80, an upper elastic porous body 84, and a band, etc. The backrest cushion material 51 is positioned above the backrest frame 25 and the band wrapped around the metal pipe of the backrest frame 25 when the backrest of the chair 10 is tilted backward. The backrest cushion material 51, the lower elastic porous body 80, and the upper elastic porous body 84 are arranged to surround the backrest frame 25 (and band) on all sides (top, bottom, left, and right). The lower elastic porous body 80 covers the lower surface of the backrest cushion material 51 and the backrest frame 25, and the upper elastic porous body 84 covers the upper surface of the seat cushion material 31. The ends of the lower elastic porous body 80 and the upper elastic porous body 84 are bonded together via the adhesive layer 86B, forming a bag-like structure.

[0030] The head section 17 has the same configuration as the seat section 13 and the backrest section 15. As shown in Figure 3, the head section 17 comprises a head section frame 27, a head section cushioning material 71, a lower elastic porous body 80, an upper elastic porous body 84, and a band, etc. The head section cushioning material 71 is positioned above the head section frame 27 and the band wrapped around the metal pipe of the head section frame 27 when the backrest of the chair 10 is tilted backward. The head section cushioning material 71, the lower elastic porous body 80, and the upper elastic porous body 84 are arranged to surround the head section frame 27 (and band) on all sides (top, bottom, left, and right). The lower elastic porous body 80 covers the lower surface of the head section cushioning material 71 and the head section frame 27, and the upper elastic porous body 84 covers the upper surface of the head section cushioning material 71. The ends of the lower elastic porous body 80 and the ends of the upper elastic porous body 84 are bonded together via an adhesive layer 86B, forming a bag shape.

[0031] Each of the cushioning materials, such as the seat cushioning material 31, the backrest cushioning material 51, or the head cushioning material 71, can be made of an elastic material. Examples of elastic materials include foams and fibrous porous materials. Foams are preferred as cushioning materials from the viewpoint of ease of processing. Examples of materials for cushioning materials include soft foams, and polyurethane foam is preferable in terms of elasticity. The cushioning material may be a single layer or a composite of multiple materials laminated together. The shape of the cushioning material is easiest to handle as a sheet-like flat plate shape, and in addition to a sheet-like flat plate shape, it may also have depressions or protrusions, and may have an uneven surface.

[0032] Each cushioning material can be used as a core material for various types of cushions. For example, in a floor chair, each cushioning material can be used as the cushioning material for the seat 13 (seat cushioning material 31), the cushioning material for the backrest 15 (backrest cushioning material 51), and the cushioning material for the headrest 17 (headrest cushioning material 71). Each cushioning material can also be used for chair seats, sofa seats, cushions, mattresses, bedding, etc.

[0033] The seat cushion material 31 is the core material of the cushion, and comprises a first chip urethane layer 81, a second chip urethane layer 82, and a third chip urethane layer 83 (Figure 5). The first chip urethane layer 81 is formed in layers of chip urethane containing small pieces of polyurethane foam and a binder. The second chip urethane layer 82 and the third chip urethane layer 83 have the same material as the first chip urethane layer 81.

[0034] The first chip urethane layer 81, the second chip urethane layer 82, and the third chip urethane layer 83 can be made of ribbon dead foam, which is obtained by crushing and fragmenting soft polyurethane foam and then solidifying it with a binder. Ribbon dead foam is made by coating polyurethane chips, which are fragments of polyurethane foam, with a binder and then solidifying it.

[0035] Small pieces of polyurethane foam are obtained by crushing polyurethane foam into small pieces using a crusher or similar device. For example, waste materials from polyurethane foam products or scraps generated during the manufacturing of polyurethane foam may be crushed and used as small pieces.

[0036] First, the manufacturing method for ribbon-dead foam involves crushing waste and scraps of polyurethane foam to create small pieces of polyurethane foam. Next, a binder is mixed with these polyurethane foam pieces to create a binder mixture. Subsequently, the binder mixture is compressed, and the binder binds the polyurethane foam pieces together, forming the desired shape. Compression, binding, and shaping are usually carried out by mold molding or press molding. In mold molding, the binder mixture is filled into a mold, pressurized, and heated as needed to bind the polyurethane foam pieces together with the binder, shaping them to the shape of the mold's inner surface and allowing them to solidify. In press molding, the binder mixture is pressed to bind the polyurethane foam pieces together with the binder and shape them to the desired form.

[0037] Before being formed into ribbon-dead foam, small pieces of polyurethane foam are crushed and broken down into smaller pieces using a crushing device that has a rotary crushing mechanism in which blades or needles are erected on the outer circumference of a drum that rotates with a motor. The size of each individual piece of polyurethane foam is determined as appropriate, but is usually around 3 to 25 mm.

[0038] A known binder for ribbon-dead foam can be used, and the cured film will have elasticity similar to an elastic elastomer. For example, a one-component or two-component urethane adhesive can be used, and a one-component urethane binder that cures with moisture such as humidity is particularly suitable. The amount of binder can be determined as appropriate, but for example, about 4 to 40 parts by weight can be used per 100 parts by weight of the chip.

[0039] <Structure of chipped urethane> Figure 7 is a schematic diagram of ribbon dead foam (chip urethane). In the figure, the white areas represent small pieces 92A of polyurethane foam, and the binder 92B surrounding them is represented by black lines. Ribbon dead foam (chip urethane) is formed by mixing crushed small pieces 92A of polyurethane foam with binder 92B, then compressing the binder mixture, and bonding the small pieces 92A of polyurethane foam together with the binder 92B.

[0040] Therefore, chip urethane 91 (ribbon dead foam) has a composite structure in which a binder 92B is coated around each individual piece 92A of polyurethane foam, and adjacent pieces 92A of polyurethane foam are bonded together by the binder 92B. Consequently, compared to ordinary, general-purpose soft polyurethane foam of the same density, chip urethane 91 (ribbon dead foam) exhibits higher stress when compressed and higher resilience.

[0041] The density of chip urethane (ribboned foam), which is formed by bonding polyurethane chips with a binder, is 30-120 kg / m³. 3is the degree. From the viewpoints of cushioning properties and resistance to sagging, 40 kg / m 3 or more is preferable, 50 kg / m 3 or more is more preferable, and 60 kg / m 3 or more is even more preferable. From the viewpoint of light weight, 110 kg / m 3 or less is preferable, 100 kg / m 3 or less is more preferable, and 90 kg / m 3 or less is even more preferable. If the density of the ribboned foam (chip urethane) is lower than the lower limit value (30 kg / m 3 ), it becomes difficult to be suitable for applications such as cushioning materials. Also, if it is higher than the upper limit value (120 kg / m 3 ), it becomes heavy and it is difficult to obtain a light weight effect.

[0042] Note that the chip urethane (ribboned foam) is produced by mixing small pieces of polyurethane foam with a binder and subjecting them to known molding or press molding. Therefore, the density of the chip urethane can be adjusted by adjusting the degree of compression during molding or press molding.

[0043] Furthermore, the chip urethane (ribboned foam) used for the seat cushion material 31, the backrest cushion material 51, and the head cushion material 71 is harder and has a higher density than the sheet-like lower elastic porous body 80 and the upper elastic porous body 84. Therefore, the chip urethane (ribboned foam) used for each cushion material (31, 51, 71) is suitable for supporting the load. Conversely, the sheet-like lower elastic porous body 80 and the upper elastic porous body 84 are softer and have a lower density than the chip urethane used for each cushion material (31, 51, 71), so they soften the feeling of the initial sinking when sitting. The density of the chip urethane (ribboned foam) used for each cushion material (31, 51, 71) can be, for example, 1.2 times or more, 1.5 times or more, further 2 times or more, 3 times or more the density of the sheet-like lower elastic porous body 80 and the upper elastic porous body 84.

[0044] The thicknesses of the first chip urethane layer 81, the second chip urethane layer 82, and the third chip urethane layer 83 are arbitrary. For example, they can be 10mm to 90mm, with 15mm to 80mm being preferred. A thickness of 10mm or more can prevent sagging due to use. A thickness of 80mm or less provides a good feel. The thickness of the first chip urethane layer 81, which has an uneven surface, can be, for example, 30mm to 90mm, with 50mm to 80mm being preferred.

[0045] As a core material for the cushioning material, the first chip urethane layer 81 has a shape with an uneven surface. Because the first chip urethane layer 81 has an uneven surface, it provides good displacement following ability in the low load range. The thickness of the first chip urethane layer 81, which has an uneven surface, is preferable as a cushioning material when it is thicker than the second chip urethane layer 82 and the third chip urethane layer 83, as this makes it easier to exhibit good displacement following performance in the low load range. The thickness of the first chip urethane layer 81 is greater than that of the second chip urethane layer 82 and the third chip urethane layer 83, for example, examples include being 1.2 times or more, 1.5 times or more, 2 times or more, or 3 times or more thick.

[0046] Figure 6 shows a schematic diagram of a cushioning material containing a first chip urethane layer 81 with an uneven surface, when compressed by 25% on a compression test plate 98. When the cushioning material containing the first chip urethane layer 81 with an uneven surface is compressed on the compression test plate 98, the area in contact with the compression test plate 98 and compressed becomes smaller during the initial low compression. During high compression, the area in contact with the compression test plate 98 and compressed becomes larger. Therefore, during high compression, the material exhibits its inherently high stress value. However, during low compression, a stress value smaller than the material's inherent value is exhibited. Consequently, when sitting on the cushioning material, it feels soft at first, but when sitting deeply for an extended period, it firmly supports the body weight and provides excellent stability.

[0047] Furthermore, the seat cushion material 31, backrest cushion material 51, and head cushion material 71, which use chip urethane 91 with an uneven surface, have spaces in the concave surfaces between the convex surfaces, as shown in Figures 4 and 5. Therefore, body heat and sweat emitted from the sitter's body are dissipated to the left and right through the spaces in the concave surfaces between the convex surfaces of the chip urethane 91, ensuring good breathability and preventing sweating, resulting in a comfortable seating experience even after prolonged use.

[0048] One method for creating an uneven surface on the first chip urethane layer 81 is to create a roughly rectangular or sheet-shaped ribbon dead form and then perform profile processing. Alternatively, the uneven surface can be formed during mold molding or press molding when creating the ribbon dead form by using a mold or metal plate with a pre-formed uneven shape on the inner surface of the mold or on the press surface. Generally speaking, profile processing is more economical and preferable.

[0049] Profile processing is a process in which ribbon dead foam (chip urethane) is fed between a pair of roll shafts with uneven surfaces, compressed in the thickness direction, and then cut through the center of the thickness with a cutting blade at the exit. The ribbon dead foam is compressed and deformed to match the pressing protrusions of the pair of rolls, cut in that state, and when the compression is released, the cut surface is processed into an uneven shape.

[0050] The height of the convex portion of the uneven shape that can be formed by profile processing (the distance from the bottom of the valley of the concave surface to the top of the convex surface) is 5 mm or more. From the viewpoint of forming a clear uneven shape on the surface and obtaining good cushioning properties, the height of the convex portion is preferably 10 mm or more, more preferably 15 mm or more, even more preferably 20 mm or more, and particularly preferably 25 mm or more. The upper limit is in relation to the thickness, where the height of the convex portion is 9 / 10 or less of the thickness, preferably 7 / 10 or less, more preferably 2 / 3 or less, even more preferably 3 / 5 or less, and particularly preferably 1 / 2 or less.

[0051] <Cushion composition> In this embodiment, the seat cushion material 31 comprises a first chip urethane layer 81 having an uneven surface, a flat second chip urethane layer 82, and a flat third chip urethane layer 83, which are laminated together. The flat second chip urethane layer 82 is bonded to the uneven surface of the first chip urethane layer 81, and the flat third chip urethane layer 83 is further bonded to its upper surface (Figure 5).

[0052] The first chip urethane layer 81, which has an uneven surface, is a ribboned foam formed by shaping small pieces of soft polyurethane foam with a binder, and has a density of 60 kg / m³. 3 The thickness is 60 mm. The height of the convex parts of the uneven shape (distance from the bottom of the concave surface to the top of the convex surface) is 30 mm. The flat plate-shaped second chip urethane layer 82 and the flat plate-shaped third chip urethane layer 83 are ribbon-dead foams formed by shaping small pieces of soft polyurethane foam with a binder, and have a density of 60 kg / m³. 3 It is 30mm thick.

[0053] The first chip urethane layer 81, the second chip urethane layer 82, the third chip urethane layer 83, and the lower elastic porous body 80 and upper elastic porous body 84 can be bonded together by known methods using an adhesive. Preferably, the adhesive used has an elastic film after drying, and examples include polyurethane adhesives, rubber adhesives such as polychloroprene rubber, and acrylic resin adhesives. These adhesives can be used in hot-melt, emulsion, or solvent forms.

[0054] The first chip urethane layer 81, which has an uneven surface, and the flat second chip urethane layer 82 are bonded together by spraying a rubber-based adhesive. The adhesive may be applied to both the uneven surface side of the first chip urethane layer 81 and the bonding surface of the flat second chip urethane layer 82, or to just one side. A flat third chip urethane layer 83 is placed on the flat surface of the flat second chip urethane layer 82 and bonded in the same manner.

[0055] Figure 8 is an enlarged schematic diagram of the portion where the first chip urethane layer 81, which has an uneven surface, and the second chip urethane layer 82 are bonded together. In the figure, the white area represents small pieces 92A of polyurethane foam, and a binder 92B (black lines) covers them. In this embodiment, as shown in Figure 8, adhesive is applied to both the uneven surface side of the first chip urethane layer 81 and the bonding surface of the flat second chip urethane layer 82. This allows an adhesive layer 86B to be formed on the uneven surface of the first chip urethane layer 81 and the lower surface of the second chip urethane layer 82. The first chip urethane layer 81 and the second chip urethane layer 82 are bonded together by the adhesive layer 86B. Therefore, even if strong shear forces are applied to the small pieces of polyurethane foam that are compressed and cut during profile processing, it is possible to prevent the individual crushed pieces from falling apart. Consequently, even with long-term use, it is possible to prevent the chip urethane from falling apart, resulting in excellent durability.

[0056] The backrest cushion material 51 and the head cushion material 71 are laminated and comprise a first chip urethane layer 81 having an uneven surface and a flat second chip urethane layer 82. The flat second chip urethane layer 82 is bonded to the uneven surface of the first chip urethane layer 81.

[0057] Thus, the cushioning material that forms the core of the cushion comprises a first chip urethane layer 81 having an uneven surface and a flat second chip urethane layer 82, which are laminated and bonded together. Depending on the application of the cushioning material, the core cushioning material may be a flat, flexible slab polyurethane foam instead of a flat, second chip urethane layer 82. In that case, the core cushioning material comprises a first chip urethane layer 81 having an uneven surface and a flat, flexible slab polyurethane foam, which are laminated and bonded together.

[0058] The seat portion 13, backrest portion 15, and head portion 17 of the floor chair 10 are each equipped with a seat cushion material 31, backrest cushion material 51, and head cushion material 71, respectively, as well as a main frame 21, a lower elastic porous body 80, and an upper elastic porous body 84.

[0059] The materials for the lower elastic porous body 80 and the upper elastic porous body 84 include, for example, foam and fibrous porous body. From the viewpoint of elasticity, foam is preferred for the lower elastic porous body 80 and the upper elastic porous body 84. Examples of foams include soft foam, and soft polyurethane foam is preferred in terms of elasticity. The foam may be a single layer or a composite in which other materials, such as a fiber layer or fabric, are laminated. The lower elastic porous body 80 and the upper elastic porous body 84 are preferred in the form of a sheet or flat plate for ease of handling.

[0060] The soft polyurethane foam, serving as the lower elastic porous body 80 and the upper elastic porous body 84, has, for example, a foaming ratio of 10 to 60 times and a density of 15 to 100 kg / m³. 3 Preferably 15-70 kg / m 3 A material of a certain degree can be used. The thickness of the lower elastic porous body 80 and the upper elastic porous body 84 is arbitrary. For example, the thickness of the lower elastic porous body 80 and the upper elastic porous body 84 can be 10 mm to 30 mm, preferably 15 mm to 25 mm.

[0061] In this embodiment, since a first chip urethane layer 81 having an uneven surface is used as the core material of the cushioning material, the excessive sinking of the seat surface 13 due to the user's weight when sitting is reduced, eliminating the feeling of bottoming out. Furthermore, the cushioning material is less likely to deteriorate due to aging from long-term use, maintaining a good sitting comfort.

[0062] Furthermore, the cushioning material of this embodiment is constructed by bonding a first chip urethane layer 81 having an uneven surface with a flat second chip urethane layer 82, thereby eliminating the feeling of bottoming out, suppressing sagging, and providing excellent durability. Furthermore, by laminating an elastic porous material onto the cushioning material using the first chip urethane layer 81, the ability to follow the initial load when sitting is improved, and an even better sitting comfort can be provided as a cushion.

[0063] Although the present disclosure has described the embodiments described above, it is not limited to these embodiments, and various modifications are possible without departing from the spirit of the invention. In particular, the configurations described herein can be combined as needed. [Explanation of Symbols]

[0064] 10 Folding Floor Chairs 13 Seat area 15 Backrest 17. Head section (upper part of the backrest) 21 Main frame 23 Seat frame 25 Backrest frame 27 Head frame 24. Backrest angle adjuster 26 Head Angle Adjuster 31. Seat cushion material 51 Backrest cushioning material 71 Head cushioning material 80 Lower elastic porous body 81 First chip urethane layer having an uneven surface 82. Second chip urethane layer (flat chip urethane) 83. Third chip urethane layer (flat chip urethane) 84 Upper elastic porous body 86B Adhesive layer 91 Chip Urethane (Ribbon Dead Foam) 92A Small pieces of polyurethane foam (chip-shaped polyurethane foam) 92B Chip Urethane Molding Binder 96 Bag-shaped cover material 98 Flat plate for compression testing

Claims

1. A first chip urethane layer having an uneven surface, A second chip urethane layer is placed on the uneven surface of the first chip urethane layer, A cushioning material that has the following features.

2. The second chip urethane layer is bonded to the first chip urethane layer with an adhesive. The cushioning material according to claim 1.

3. The third chip urethane layer is placed on the surface of the second chip urethane layer, The cushioning material according to claim 1, further comprising:

4. A cushioning material further comprising a bag-shaped elastic porous body covering the upper and lower surfaces of the cushioning material described in claim 1.

5. The cushioning material is provided according to any one of claims 1 to 4. Floor chair.

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