Mattress

Abstract

Provided is a mattress that makes it possible to pursue good sleeping comfort while maintaining necessary durability. The mattress has a laminate in which an upper layer, an intermediate layer, and a lower layer each comprising a three-dimensional filament assembly are laminated in the vertical thickness direction. The difference between the ratio of the thickness of the thickest layer among the layers to the thickness of the laminate and the ratio of the thickness of the thinnest layer among the layers to the thickness of the laminate is 0.2 or less, the difference between the ratio of the bulk density of the intermediate layer to the bulk density of the upper layer and the ratio of the bulk density of the intermediate layer to the bulk density of the lower layer is -0.1 or more, and the ratio of the bulk density of the intermediate layer to the bulk density of the upper layer and the ratio of the bulk density of the intermediate layer to the bulk density of the lower layer are each more than 1.0 and less than 1.5.

Description

mattress

[0001] The present invention relates to a mattress having a laminated structure.

[0002] Traditionally, mattresses have been widely used to support users in a sleeping position, and mattresses that prioritize comfort have also been proposed. For example, Patent Document 1 discloses a mattress 11 that has a two-layer structure with an upper layer 12 and a lower layer 13 stacked on top of each other, which helps to eliminate the feeling of bottoming out.

[0003] Japanese Patent Publication No. 2004-329706

[0004] Generally, mattresses tend to become harder when trying to maintain the necessary durability, making it difficult to achieve a comfortable sleeping experience. Conversely, mattresses tend to become softer when trying to achieve a comfortable sleeping experience, making it difficult to obtain good durability.

[0005] In view of these challenges, the present invention aims to provide a mattress that can pursue comfort while maintaining the necessary durability.

[0006] The mattress according to the present invention is a mattress having a laminate in which an upper layer, an intermediate layer, and a lower layer, each made of a three-dimensional filament bond, are stacked in the vertical thickness direction, wherein the difference between the ratio of the thickness of the thickest layer among the layers to the thickness of the laminate and the ratio of the thickness of the thinnest layer among the layers to the thickness of the laminate is 0.2 or less, the difference between the ratio of the bulk density of the intermediate layer to the bulk density of the upper layer and the ratio of the bulk density of the intermediate layer to the bulk density of the lower layer is -0.1 or more, and the ratio of the bulk density of the intermediate layer to the bulk density of the upper layer and the ratio of the bulk density of the intermediate layer to the bulk density of the lower layer are each greater than 1.0 and less than 1.5.

[0007] This configuration makes it possible to pursue comfort while maintaining the necessary durability. More specifically, the bulk density of the intermediate layer may be 1.2 to 1.5 times that of the upper layer. More specifically, the bulk density of the upper layer may be 0.02 to 0.045 g / cm³. 3The configuration may be as follows. The bulk density of the upper layer is 0.03 to 0.045 g / cm³. 3 The above configuration is also acceptable. The bulk density of the upper layer is 0.03 to 0.035 g / cm³. 3 The above configuration may also be used. More specifically, the portion of the lower layer within 2 mm from the upper surface may be configured such that the filament area occupancy rate when viewed from above is 55% or more.

[0008] More specifically, the above configuration may also be one in which the linearity value is 500 N or less. The linearity value in this application is obtained by following the procedure below: (1) A sample is pressed from above to below with an indenter formed in the shape of a circle with a diameter of 15 cm until the load reaches 270 N, and a graph of the measured values ​​of the relationship between the displacement (amount of indentation) and the load (load pressed by the indenter) is obtained. (2) The line segment connecting the starting point (the point where the load is 0 N) and the ending point (the point where the load is 270 N) of the graph is taken as the baseline. (3) The integral value is obtained by integrating the absolute value of the difference in load between the baseline and the graph of the measured values ​​in the range of load from 0 N to 270 N in the direction of the displacement axis. (4) The linearity value is obtained by dividing this integral value by the displacement at the point where the load is 270 N.

[0009] More specifically, the above configuration may be such that at least one of the surfaces of the upper layer and the intermediate layer that are in contact with each other, and the surfaces of the intermediate layer and the lower layer that are in contact with each other, are configured such that the filaments of the three-dimensional filament assembly intertwine, thereby suppressing positional displacement in the direction perpendicular to the vertical direction.

[0010] The mattress according to the present invention makes it possible to pursue a comfortable sleeping experience while maintaining the necessary durability.

[0011] This is a schematic perspective view of the mattress 100 according to this embodiment. This is a schematic configuration diagram of the laminate 100a according to this embodiment. This is a table showing the characteristics and evaluation results of each layer for each embodiment. This is a table showing the characteristics and evaluation results of each layer for each comparative example. This is a displacement-load graph for calculating linearity values. This is an explanatory diagram of a configuration in which each layer 101 to 103 is divided into three parts in the front-rear direction. This is a conceptual diagram of a manufacturing apparatus for a three-dimensional filament assembly. This is a view along the A-A' cross section shown in Figure 7. This is an explanatory diagram showing an example of the appearance of the nozzle section viewed from below.

[0012] 1. First, a mattress according to an embodiment of the present invention will be described. In the following description, the up and down, left and right, and front and back directions (directions that are mutually orthogonal) of the mattress are as shown in Figure 1, etc. These directions are merely defined for convenience so that the thickness direction of the mattress is the up and down direction.

[0013] Figure 1 is a schematic perspective view of the mattress 100 according to this embodiment. The mattress 100 is basically used to support a user who is in an upper sleeping position. In this case, the mattress 100 is used so that its front-to-back direction (longitudinal direction) coincides with the user's height direction.

[0014] As shown in Figure 1, the mattress 100 has a configuration in which the entire outer surface of the laminate 100a (corresponding to a cushioning core material) is covered by a mattress cover 100b. The mattress cover 100b is made entirely of a thin fabric, and its shape and dimensions are set to fit the entire outer surface of the laminate 100a. The mattress cover 100b may also be designed so that the laminate 100a can be easily inserted into and removed from the mattress.

[0015] Figure 2 is a schematic diagram of the laminate 100a as viewed from the left to right. As shown in this figure, the laminate 100a consists of an upper layer 101, an intermediate layer 102, and a lower layer 103, each layer stacked in the vertical thickness direction. Each of these layers 101 to 103 is made up of a three-dimensional filament bond and is formed in a flat plate shape with the vertical thickness direction. The three-dimensional filament bond is obtained by three-dimensionally fusing together filaments made of thermoplastic resin, and the manufacturing method of the three-dimensional filament bond will be explained in detail later.

[0016] Furthermore, the shape and dimensions of each layer 101 to 103 when viewed from above are identical, and all are rectangular in shape with the front-to-back direction as the longitudinal direction. Therefore, the laminate 100a formed by stacking each layer 101 to 103 vertically is also a flat plate shape that is rectangular when viewed from above with the top and bottom as the thickness direction. Each layer 101 to 103 is enclosed in the mattress cover 100b, maintaining a unified state and forming a flat plate-shaped laminate 100a. Note that the configuration of the laminate 100a is not limited to this, and for example, the laminate 100a may be integrated by partially bonding adjacent layers 101 to 103 together.

[0017] Incidentally, in mattresses, sufficient durability of the core material is required, and in order to pursue a comfortable sleeping experience, the feel of the core material is also required. The inventors have diligently researched this point and, focusing on the thickness and bulk density of each of the aforementioned layers 101 to 103, have found that if the laminate 100a satisfies all of the following conditions (1) to (3), then a good balance of feel and durability can be achieved. Condition (1): The difference (= R1 - R2) between the ratio of the thickness of the thickest layer among each of the layers 101 to 103 to the thickness of the laminate 100a (hereinafter, for convenience, referred to as "first thickness ratio R1") and the ratio of the thickness of the thinnest layer among each of the layers 101 to 103 to the thickness of the laminate 100a (hereinafter, for convenience, referred to as "second thickness ratio R2") is 20% or less. Condition (2): The difference (= h1 - h2) between the ratio of the bulk density of the intermediate layer 102 to the bulk density of the upper layer 101 (hereinafter referred to as the "first bulk density ratio h1" for convenience) and the ratio of the bulk density of the intermediate layer 102 to the bulk density of the lower layer 103 (hereinafter referred to as the "second bulk density ratio h2" for convenience) is -0.1 or greater. Condition (3): The first bulk density ratio h1 and the second bulk density ratio h2 are both greater than 1.0 and less than 1.5.

[0018] Here, the evaluation tests conducted regarding the above conditions (1) to (3) are described below. Laminates 100a of Examples 1 to 5 were created to satisfy all of conditions (1) to (3), and laminates 100a of Comparative Examples 1 to 6 were created to not satisfy at least one of conditions (1) to (3). For reference, Comparative Example 1 was an example in which the intermediate layer 102 was omitted and the laminate 100a was constructed with the upper layer 101 and the lower layer 103. Evaluation tests were then conducted to evaluate the feel and durability of the laminates 100a of each example and comparative example.

[0019] The table in Figure 3 shows the characteristics of each layer 101 to 103 in the laminate 100a of Examples 1 to 5, and the evaluation results (results of the evaluation test). The table in Figure 4 shows the characteristics of each layer 101 to 103 in the laminate 100a of Comparative Examples 1 to 6, and the evaluation results.

[0020] In the tables in Figures 3 and 4, the characteristics of each layer 101 to 103 in the laminate 100a are shown, with measured values ​​for thickness, bulk density, and filament area occupancy for each layer 101 to 103. For example, in Figure 3, the measured values ​​for Example 1 are: the thickness of the upper layer 101 is 80 mm, the thickness of the intermediate layer 102 is 50 mm, the thickness of the lower layer 103 is 80 mm, and the bulk density of the upper layer 101 is 0.0362 g / cm³. 3 The bulk density of the intermediate layer 102 is 0.0476 g / cm³. 3 The bulk density of the lower layer 103 is 0.0362 g / cm³. 3 It is shown that the filament area occupancy rate of the upper layer 101 is 39%, the filament area occupancy rate of the intermediate layer 102 is 43%, and the filament area occupancy rate of the lower layer 103 is 39%. The "filament area occupancy rate" is a value that represents the ratio of the area occupied by the filament (the part that does not penetrate vertically) to the total area (including the part that penetrates vertically) when viewed from above (when viewed from above) in the upper surface vicinity portion (the part within 2 mm from the upper surface).

[0021] Furthermore, as reference values ​​A, the ratio of the thickness of each layer 101 to 103 to the thickness of the laminate 100a is shown, and regarding bulk density, the first bulk density ratio h1 is shown for the upper layer 101, and the second bulk density ratio h2 is shown for the lower layer 103. For example, as reference values ​​A for Example 1 in Figure 3, the ratio of the thickness of the upper layer 101 to the thickness of the laminate 100a is shown to be 38.1%, the ratio of the thickness of the intermediate layer 102 to the thickness of the laminate 100a is shown to be 23.8%, the ratio of the thickness of the lower layer 103 to the thickness of the laminate 100a is shown to be 38.1%, the first bulk density ratio h1 is 1.31, and the second bulk density ratio h2 is 1.31.

[0022] Furthermore, as reference values ​​B, for thickness, the difference between the first thickness ratio R1 and the second thickness ratio R2 (= R1 - R2) is shown, and for bulk density, the difference between the first bulk density ratio h1 and the second bulk density ratio h2 (= h1 - h2) is shown. For example, as reference values ​​B for Example 1 in Figure 3, the difference between the first thickness ratio R1 and the second thickness ratio R2 (= R1 - R2) is 14.3%, and the difference between the first bulk density ratio h1 and the second bulk density ratio h2 (= h1 - h2) is 0. Note that if the reference value B for thickness is 20% or less, condition (1) is satisfied, and if the reference value B for bulk density is -0.1 or more, condition (2) is satisfied.

[0023] As can be seen from the table in Figure 3, Examples 1 to 5 satisfy all of conditions (1) to (3). On the other hand, as can be seen from the table in Figure 4, Comparative Examples 1 and 2 do not satisfy condition (1), Comparative Examples 3 and 6 do not satisfy condition (3), Comparative Example 4 does not satisfy conditions (2) and (3), and Comparative Example 5 does not satisfy condition (2).

[0024] Furthermore, in the tables in Figures 3 and 4, the evaluation results for "feel" and "durability" are shown. For example, in Example 1 in Figure 3, the evaluation result for "feel" is 142.6 mm, which is "Good," and the evaluation result for "durability" is 23.2 mm, which is "Good."

[0025] The evaluation test to obtain these results was conducted using an indenter with a circular tip (contact surface with the sample) with a diameter of 15 cm. The test involved pressing a sample of mattress 100 (a laminated body 100a covered with a mattress cover 100b) downwards with this indenter. More specifically, the evaluation test for "touch" involved pressing the sample with a force of 270 N using the indenter. If the amount of indentation of the sample (the displacement of the indenter from its position at the moment of contact with the sample) exceeded 133 mm, it was evaluated as "Good" (relatively soft and good touch), and if it was 133 mm or less, it was evaluated as "No Good" (too hard and not good touch). Furthermore, for the "durability" evaluation test, a sample was pressed down with a force of 270N using an indenter for 70 hours, and then the indenter was lifted and the load removed. After waiting for 2 hours, if the measured amount of indentation in the sample after the waiting period was 25mm or less, it was evaluated as "Good" (good durability), and if it exceeded 25mm, it was evaluated as "No Good" (poor durability).

[0026] As shown in Figure 3, Examples 1 to 5 received a "Good" rating for both "feel" and "durability." On the other hand, as shown in Figure 4, Comparative Examples 1 and 2 received a "Good" rating for "feel," but a "No Good" rating for "durability." Comparative Examples 3 to 6 received a "Good" rating for "durability," but a "No Good" rating for "feel." From these evaluation results, it can be concluded that in each comparative example, at least one of the evaluation results for "feel" or "durability" was "No Good," but in each example, both evaluation results were "Good," confirming that it is possible to achieve a good balance between feel and durability.

[0027] Note that, for the portion within 2 mm from the upper surface in the lower layer 103 (that is, the vicinity of the surface in contact with the intermediate layer 102), by setting the filament area occupancy rate to 55% or more, the intermediate layer 102 can be firmly supported by the lower layer 103. In Example 2, as shown in the table of FIG. 3, the filament area occupancy rate for the lower layer 103 is 55% or more (63%).

[0028] Also, the bulk density of the intermediate layer 102 in the laminate 100a is preferably moderately higher than the bulk density of the upper layer 101. Basically, the bulk density of the intermediate layer 102 may be set to 1.2 to 1.5 times the bulk density of the upper layer 101. The value of the bulk density of the upper layer 101 is preferably set to an appropriate value in consideration of comfort. Basically, the bulk density of the upper layer 101 3 may be set to be 0.02 to 0.045 g / cm 3 More preferably, the bulk density of the upper layer 101 may be set to be 0.03 to 0.045 g / cm 3 Still more preferably, the bulk density of the upper layer 101 may be set to be 0.03 to 0.035 g / cm

[0029] Note that the surfaces of the upper layer 101 and the intermediate layer 102 that contact each other (that is, the surfaces of the lower surface of the upper layer 101 and the upper surface of the intermediate layer 102) may be such that the filaments of the filament three-dimensional conjugate bodies of the upper layer 101 and the intermediate layer 102 are intertwined to suppress displacement in the direction perpendicular to the up and down direction. Also, the surfaces of the intermediate layer 102 and the lower layer 103 that contact each other (that is, the surfaces of the lower surface of the intermediate layer and the upper surface of the lower layer 103) may be such that the filaments of the filament three-dimensional conjugate bodies of the intermediate layer 102 and the lower layer 103 are intertwined to suppress displacement in the direction perpendicular to the up and down direction.

[0030] Thus, at least one of the surfaces of the upper layer 101 and the intermediate layer 102 that are in contact with each other, and the surfaces of the intermediate layer 102 and the lower layer 103 that are in contact with each other, may be configured so that the filaments of the three-dimensional filament assembly intertwine, thereby suppressing positional displacement in the direction perpendicular to the vertical direction. Note that the cut surface of the three-dimensional filament assembly described later (the surface created by cutting with a cutter, etc.) has many filament ends (cut ends) exposed, and when these cut surfaces come into contact with each other, the filaments tend to intertwine particularly easily. Therefore, at least one of the surfaces of the upper layer 101 and the intermediate layer 102 that are in contact with each other, and the surfaces of the intermediate layer 102 and the lower layer 103 that are in contact with each other may be configured so that they are the cut surfaces described above.

[0031] Furthermore, regarding the characteristics of the core material in a mattress, it is desirable that the relationship between the displacement (amount of indentation) when pressed from above and the load be as close to a proportional relationship as possible (in other words, that the displacement-load graph be as close to a straight line as possible). The closer the relationship is to a proportional relationship, the more consistent the way the mattress sinks when a user sits on it and applies a load, making it possible to avoid causing discomfort to the user. When we investigated this point, we found that in laminated bodies 100a that satisfy all of the aforementioned conditions (1) to (3), the graph tended to be relatively close to a straight line.

[0032] Figure 5 shows the relationship between measured displacement and load when a sample of the laminate 100a is pressed from above using the indenter described above, as a displacement-load graph. Here, the laminate 100a from Example 2 and the laminate 100a from Comparative Example 1 described above were used as samples of the laminate 100a. As a reference example, the same relationship is also shown in the graph for a single-layer filament three-dimensional assembly. The indenter was pressed until the load pressing the indenter reached 270 N for the laminate 100a of Example 2 and Comparative Example 1, and until the amount of indentation reached 50% of the thickness of the filament three-dimensional assembly for the reference example.

[0033] Furthermore, in Figure 5, the line segment connecting the starting point (the point where the load is 0 N) and the ending point (the point where the load is 270 N for Example 2 and Comparative Example 1) of each graph is shown as the baseline. This baseline corresponds to a graph (ideal line) assuming a proportional relationship between displacement and load, and it can be said that the closer the graph of the measured values ​​is to the baseline, the more preferable it is.

[0034] Therefore, for loads ranging from 0 N to 270 N, the absolute value of the difference between the baseline and the measured value graph is integrated along the axis of displacement (a value corresponding to the area enclosed by the baseline and the measured value graph). This integral value is then divided by the displacement (amount of indentation) at the point where the load is 270 N, and this value is defined as the linearity value (in N). The smaller this linearity value, the closer the measured value graph is to the baseline, which is preferable.

[0035] When the linearity values ​​were calculated for each laminate 100a of Example 2 and Comparative Example 1 shown in the graph of Figure 5, the linearity value of Example 2 was 107 N, and the linearity value of Comparative Example 1 was 1316 N. Thus, it was found that Example 2 yielded a linearity value that was significantly better than that of Comparative Example 1. The linearity value of the laminate 100a is preferably 800 N or less, and more preferably 500 N or less.

[0036] In this embodiment, each layer 101 to 103 of the laminate 100a is an integral structure, but all or part of these layers 101 to 103 may be divided into multiple parts. In this way, it is possible to divide them as needed to obtain parts smaller than the entirety of each layer 101 to 103, thereby improving the convenience of handling during washing, etc. As an example, as shown in Figure 6, each layer 101 to 103 may be divided into three parts in the front-to-back direction. In the example shown in Figure 6, the upper layer 101 is divided into three parts 101a to 101c, the middle layer 102 is divided into three parts 102a to 102c, and the lower layer 103 is divided into three parts 103a to 103c.

[0037] 2. Manufacturing Apparatus for Filament Three-Dimensional Structure Next, an example of a manufacturing apparatus for a filament three-dimensional structure capable of manufacturing the filament three-dimensional structures of each layer 101 to 103 of the laminate 100a described above will be described.

[0038] FIG. 7 is a conceptual diagram of a manufacturing apparatus 1 for a filament three-dimensional structure. FIG. 8 is a view of the arrow in the A-A' cross section shown in FIG. 7. The vertical, horizontal, and front-rear directions (directions orthogonal to each other) regarding the manufacturing apparatus 1 are as shown in each figure. These directions are merely defined for convenience such that the vertical direction is the up-down direction and the facing direction between a pair of endless conveyors 26 and 27 described later is the front-rear direction.

[0039] The manufacturing apparatus 1 for a filament three-dimensional structure includes a molten filament supply unit 10 that discharges a molten filament group MF composed of a plurality of molten filaments with a diameter of 0.3 to 3.0 mm downward in the vertical direction, and a fusion bonding formation unit 20 that three-dimensionally entangles the molten filament group MF, fuses and bonds the contact points, and then cools and solidifies them to form a filament three-dimensional structure.

[0040] The molten filament supply unit 10 includes a pressure melting unit 11 (extruder) and a filament discharge unit 12 (die). The pressure melting unit 11 includes a material input unit 13 (hopper), a screw 14, a screw motor 15 that drives the screw 14, a screw heater 16, and a plurality of temperature sensors (not shown). Inside, a cylinder 11a is formed for conveying the thermoplastic resin supplied from the material input unit 13 while heating and melting it with the screw heater 16.

[0041] Inside the cylinder 11a, the screw 14 is rotatably accommodated. A cylinder discharge port 11b for discharging the thermoplastic resin toward the filament discharge unit 12 is formed at the downstream end of the cylinder 11a. The heating temperature of the screw heater 16 is controlled based on, for example, the detection signal of the temperature sensor provided in the molten filament supply unit 10.

[0042] The filament discharge part 12 includes a nozzle part 17, a die heater 18, and a plurality of temperature sensors (not shown), and a flow guide path 12a for guiding the molten thermoplastic resin discharged from the cylinder discharge port 11b to the nozzle part 17 is formed inside.

[0043] The nozzle part 17 is a substantially rectangular parallelepiped metal thick plate in which a plurality of openings are formed, and is provided below the filament discharge part 12 corresponding to the most downstream part of the flow guide path 12a. A plurality of nozzle holes for discharging a molten filament group are formed in the nozzle part 17. FIG. 9 shows an example of a schematic appearance when viewed from below the nozzle part 17. In the nozzle part 17 shown in FIG. 9, each nozzle hole is circular when viewed from below, and the nozzle diameter and nozzle interval are constant.

[0044] A plurality of (six in the example shown in FIG. 8) die heaters 18 are provided in the left-right direction and heat the filament discharge part 12. The heating temperature of the die heater 18 is controlled based on, for example, the detection signal of a temperature sensor provided in the filament discharge part 12.

[0045] As the thermoplastic resin that can be used as the material of the filament three-dimensional conjugate body, for example, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon 66, polyolefin elastomers, polyester elastomers, polyurethane elastomers, polyamide elastomers, amorphous polystyrene elastomers, crystalline polystyrene elastomers, etc. can be used.

[0046] The thermoplastic resin supplied from the material input part 13 is heated and melted in the cylinder 11a, and is supplied as a molten thermoplastic resin from the cylinder discharge port 11b to the flow guide path 12a of the filament discharge part 12, for example, by being extruded by a screw 14. Then, a molten filament group MF composed of a plurality of molten filaments is discharged so as to translate downward from each of the plurality of nozzles of the nozzle part 17.

[0047] The fusion bonding unit 20 includes a cooling water tank 21, a pair of endless conveyors 26 and 27, a plurality of transport rollers 28 to 35, a pair of chutes 22 and 23, and cooling water supply units 24 and 25 that supply cooling water to the upper parts of the chutes 22 and 23, respectively.

[0048] The cooling water tank 21 is a tank for storing cooling water W. Inside the cooling water tank 21 are a pair of endless conveyors 26 and 27 and a plurality of transport rollers 28 to 35. The pair of endless conveyors 26 and 27 and the plurality of transport rollers 28 to 35 are driven by a drive motor (not shown).

[0049] The pair of chutes 22 and 23 receive the molten filaments at the thickness-direction ends (both left and right ends in the front-to-back direction) of the molten filament group MF, and move them toward a direction that reduces the thickness of the molten filament group MF. In this way, the pair of chutes 22 and 23 move the molten filaments toward a direction that reduces the thickness of the molten filament group MF, thereby reducing the void ratio of the front and rear surfaces of the three-dimensional filament assembly 3DF. If the surface with reduced void ratio becomes the upper surface of each of the aforementioned layers 101 to 103, it becomes easy to increase the filament area occupancy rate for each of the layers 101 to 103.

[0050] In the fusion bonding section 20, the molten filament group MF is adjusted in thickness (front-to-back dimension) by a pair of chutes 22 and 23, and bends due to the buoyancy of the cooling water W in the cooling water tank 21, causing each molten filament to form a random loop. The random loops intertwine three-dimensionally with adjacent random loops in a molten state, and at the same time, the contact points fuse together to form a three-dimensional filament assembly 3DF (a three-dimensional filament assembly). As this three-dimensional filament assembly 3DF is conveyed between endless conveyors 26 and 27, it is further cooled by the cooling water W while maintaining its thickness and solidifies.

[0051] Furthermore, the three-dimensional filament assembly 3DF is transported by multiple transport rollers 28-35 while being cooled by the cooling water W in the cooling water tank 21, and then sent out of the cooling water tank 21. The three-dimensional filament assembly 3DF sent out of the cooling water tank 21 is cut to an appropriate size by a cutter or the like, and can be used as each layer 101-103 of the laminate 100a described above.

[0052] Here, the bulk density of the filament three-dimensional assembly 3DF can be adjusted, for example, by changing the shape of the multiple nozzle holes in the nozzle section 17 mentioned above. For example, by increasing the inner diameter of the nozzle holes (nozzle diameter) or decreasing the spacing between adjacent nozzle holes (nozzle spacing), the bulk density of the manufactured filament three-dimensional assembly 3DF can be increased, and layers 101 to 103 with high bulk density can be obtained.

[0053] Furthermore, the bulk density of the three-dimensional filament assembly 3DF can also be changed by altering the amount of molten filament group MF discharged from the nozzle section 17 per unit time, or by changing the transport speed of the three-dimensional filament assembly 3DF by changing the drive speed of the endless conveyors 26, 27 and the multiple transport rollers 28-35. Basically, the more the amount of molten filament group MF discharged from the nozzle section 17 per unit time is increased, or the slower the transport speed of the three-dimensional filament assembly 3DF is slowed, the higher the bulk density of the manufactured three-dimensional filament assembly 3DF becomes, and layers 101-103 with high bulk density can be obtained.

[0054] 3. Other The mattress 100 in each of the embodiments described above (Embodiments 1 to 5) is a mattress having a laminate 100a in which each of the layers, an upper layer 101, an intermediate layer 102, and a lower layer 103, made of a three-dimensional filament bond, is stacked in the vertical thickness direction, and the difference between the ratio of the thickness of the thickest layer among the layers to the thickness of the laminate 100a and the ratio of the thickness of the thinnest layer among the layers to the thickness of the laminate 100a is 0.2 or less. Furthermore, the difference between the ratio of the bulk density of the intermediate layer 102 to the bulk density of the upper layer 101 and the ratio of the bulk density of the intermediate layer 102 to the bulk density of the lower layer 103 is -0.1 or more, and the ratio of the bulk density of the intermediate layer 102 to the bulk density of the upper layer 101 and the ratio of the bulk density of the intermediate layer 102 to the bulk density of the lower layer 103 are each greater than 1.0 and less than 1.5. Therefore, with the mattress 100, it is possible to pursue a comfortable sleeping experience while maintaining the necessary durability.

[0055] It should be noted that the above embodiments are illustrative in all respects and not restrictive. The technical scope of the present invention is indicated by the claims rather than by the above descriptions of embodiments, and should be understood to include all modifications that fall within the meaning and scope of the equivalents of the claims.

[0056] This invention can be used in mattresses.

[0057] 1. Manufacturing apparatus for three-dimensional filament assemblies 10. Molten filament supply section 11. Pressurized melting section 11a. Cylinder 11b. Cylinder discharge port 12. Filament discharge section 12a. Guide channel 13. Material input section 14. Screw 15. Screw motor 16. Screw heater 17. Nozzle section 17a. Nozzle hole 18. Die heater 20. Fusion bonding section 21. Cooling water tank 22, 23. Chute 24, 25. Cooling water supply section 26, 27. Endless conveyor 28-35. Conveyor rollers 100. Mattress 100a. Laminate 100b. Mattress cover 101. Upper layer 101a-101c. Parts of the upper layer 102. Middle layer 102a-102c. Parts of the middle layer 103. Lower layer 103a-103c. Parts of the lower layer

Claims

1. A mattress having a laminate in which an upper layer, an intermediate layer, and a lower layer, each made of a three-dimensional filament bond, are stacked in the vertical thickness direction, wherein the difference between the ratio of the thickness of the thickest layer among the layers to the thickness of the laminate and the ratio of the thickness of the thinnest layer among the layers to the thickness of the laminate is 0.2 or less, the difference between the ratio of the bulk density of the intermediate layer to the bulk density of the upper layer and the ratio of the bulk density of the intermediate layer to the bulk density of the lower layer is -0.1 or more, and the ratio of the bulk density of the intermediate layer to the bulk density of the upper layer and the ratio of the bulk density of the intermediate layer to the bulk density of the lower layer are each greater than 1.0 and less than 1.

5.

2. The mattress according to claim 1, characterized in that the bulk density of the intermediate layer is 1.2 to 1.5 times that of the upper layer.

3. The bulk density of the upper layer is 0.02 to 0.045 g / cm³. 3 The mattress according to claim 1 or 2, characterized in that it is the same as the mattress according to claim 2.

4. The mattress according to claim 1 or 2, characterized in that the portion of the lower layer within 2 mm from the upper surface has a filament area occupancy rate of 55% or more when viewed from above.

5. The mattress according to claim 1 or 2, characterized in that the linearity value is 500 N or less.

6. The mattress according to claim 1 or 2, characterized in that at least one of the surfaces of the upper layer and the intermediate layer that are in contact with each other, and the surfaces of the intermediate layer and the lower layer that are in contact with each other, is such that the filaments of the three-dimensional filament assembly intertwine, thereby suppressing displacement in a direction perpendicular to the vertical direction.

Images