Seat pad and method for manufacturing the same

Abstract

Provided are: a seat pad which improves thermal comfort and improves vibration absorption properties; and a method for producing a seat pad with which it is possible to easily obtain said seat pad. When a surface section (2) extending 10mm from the surface (1f) of a seat pad (1) is cut out and the airflow rate AR1 of said surface section (2) is measured according to JIS K 6400, said airflow rate AR1 is greater than 5cc / cm2 / sec and no greater than 25cc / cm2 / sec. This method for producing a seat pad involves obtaining a seat pad (1) by foam-molding by supplying a molding material to the interior of a mold. The inner surface of the mold to be used is covered with a polystyrene or a polyethylene.

Description

[Technical Field]

[0001] The present invention relates to a seat pad and a method for manufacturing a seat pad. [Background technology]

[0002] Some conventional seat pads have a part of their surface made smooth with a surface roughness of 2 to 20 μm, and the amount of air permeability of the surface of the smooth part is kept low (see, for example, Patent Document 1). With such conventional seat pads, the amount of air permeability of the surface is kept low, resulting in a seat pad with sufficiently low vibration transmissibility and excellent vibration absorption. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5393085 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional seat pads have the risk of trapping heat and causing stuffiness when sitting for a long period of time. In other words, the conventional seat pads have room for improvement in terms of improving thermal comfort and vibration absorption.

[0005] An object of the present invention is to provide a seat pad that improves thermal comfort and vibration absorption, and a method for manufacturing the seat pad that can easily obtain the seat pad. [Means for solving the problem]

[0006] The seat pad according to the present invention has a surface portion cut out to 10 mm from the surface, and the air permeability of the surface portion measured in accordance with JIS K 6400 is 5 cc / cm 2 / sec and greater than 25cc / cm 2 / sec or less.

[0007] In the seat pad according to the present invention, when a core portion located inside the surface portion is cut out and the air permeability of the core portion is measured in accordance with the JIS K 6400 standard, it is preferable that the air permeability is greater than the air permeability of the surface portion.

[0008] In the seat pad according to the present invention, the seat pad includes a cushion pad, and the sitting portion of the cushion pad is divided into an under-buttocks portion and a under-knee portion, and the air permeability of the surface portion on the seat side of the under-buttocks is within the range described in claim 1, and the air permeability of the surface portion of the under-knees portion can be greater than the air permeability of the surface portion of the under-buttocks portion.

[0009] In the seat pad according to the present invention, the seat pad includes a cushion pad, and the overall air permeability of the surface portion on the seat side of the cushion pad can be limited to an air permeability within the range described in claim 1.

[0010] In the seat pad according to the present invention, the air permeability of the surface portion of the entire surface of the cushion pad can be limited to an air permeability within a range as set forth in claim 1.

[0011] The seat pad of the present invention has a groove that separates an air-permeability restricted area, in which the air permeability of the surface area is limited to the range described in claim 1, from other areas adjacent to the air-permeability restricted area, and the surface area of ​​the air-permeability restricted area can include the surface area of ​​the side of the groove that is connected to the air-permeability restricted area.

[0012] The method for manufacturing a seat pad according to the present invention is a method for manufacturing a seat pad, in which a molding material is supplied into a mold and foam-molded to obtain each of the above-mentioned seat pads, and the mold used is a mold whose inner surface is coated with polystyrene or polyethylene.

[0013] In the method for manufacturing a seat pad according to the present invention, the mold is a mold for obtaining a cushion pad, and as the mold, a mold in which the inner surface on the seat side of the cushion pad is locally coated with the polystyrene or the polyethylene can be used.

[0014] In the method for manufacturing a seat pad according to the present invention, the mold is a mold for obtaining a cushion pad, and as the mold, a mold in which the entire inner surface on the seat side of the cushion pad is covered with the polystyrene or the polyethylene can be used.

[0015] In the method for manufacturing a seat pad according to the present invention, the molding die can be a molding die whose inner surface, which forms the surface of the cushion pad, is entirely covered with the polystyrene or the polyethylene.

[0016] In the method for manufacturing a seat pad according to the present invention, the mold has a protrusion that divides the inner surface of the mold and is covered with the polystyrene or the polyethylene, and the polystyrene or the polyethylene can cover the side of the protrusion.

[0017] In the method for manufacturing a seat pad according to the present invention, it is preferable to use, as the mold, a mold whose inner surface is covered with high-density polyethylene.

[0018] In the method for manufacturing a seat pad according to the present invention, it is preferable to use, as the mold, a mold whose inner surface is covered with polystyrene.

[0019] In the method for manufacturing a seat pad according to the present invention, it is preferable to use, as the molding die, a molding die whose inner surface is coated with low-density polyethylene. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a seat pad that improves thermal comfort and vibration absorption, and a method for manufacturing the seat pad that can easily obtain the seat pad. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view schematically showing a seat including a seat pad according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of a seat pad according to the embodiment, which constitutes a part of the seat shown in FIG. 1, taken along the line AA in FIG. 1. FIG. [Figure 3] FIG. 3 is a diagram schematically illustrating the surface of the seat pad of FIG. 2. [Figure 4] FIG. 10 is a diagram schematically illustrating the surface of a seat pad of a comparative example. [Figure 5] FIG. 10 is a plan view schematically showing a seat pad according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a plan view schematically showing a seat pad according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a plan view schematically showing a seat pad according to a fourth embodiment of the present invention. [Figure 8] 8 is a cross-sectional view of FIG. 7 taken along line B-B. [Figure 9A] 2 is a cross-sectional view schematically showing a molding die that can be used in a method for producing the seat pad of FIG. 1 in a state before the die is clamped. FIG. [Figure 9B] FIG. 9B is a cross-sectional view schematically showing the mold of FIG. 9A in a clamped state. [Figure 10] 8 is a cross-sectional view schematically showing a mold that can be used in a method for producing the seat pad of FIG. 7 in a clamped state. FIG. [Figure 11] 7 is a cross-sectional view schematically showing a mold that can be used in a method for producing the seat pad of FIG. 6 in a clamped state. FIG. [Figure 12] 10 is a graph showing a comparison of the vibration transmissibility of a seat pad according to the present invention with that of a seat pad of a comparative example. [Figure 13] 10 is a graph showing the relationship between the surface air permeability of the seat pad and the resonance magnification. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, a seat pad and a method for manufacturing a seat pad according to an embodiment of the present invention will be described with reference to the drawings.

[0023] [Seat pad] Fig. 1 is a perspective view schematically illustrating a seat 10 including a seat pad 1 according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view of the seat pad 1 according to the same embodiment, which constitutes a part of the seat 10, taken along the line AA in Fig. 1.

[0024] In the example of FIG. 1, the seat 10 is a seat for an automobile. The seat 10 includes a seat pad 1 according to this embodiment. In FIG. 1, the seat pad 1 is indicated by a dashed line. The seat pad 1 according to this embodiment includes a cushion pad 1a on which a seated person sits, and a back pad 1b for supporting the back of the seated person. In this example, the seat 10 further includes a cover 11 covering the front side of the seat pad 1, a frame (not shown) supporting the cushion pad 1a from below, a frame (not shown) installed on the back side of the back pad 1b, and a headrest 12 for supporting the head of the seated person. The cover 11 is made of, for example, a breathable material (such as cloth).

[0025] The seat pad 1 is made of a resin foam. The resin foam is preferably a soft resin foam, more preferably a soft polyurethane foam. In this embodiment, the cushion pad 1a and the back pad 1b are formed as separate bodies. However, the cushion pad 1a and the back pad 1b can be formed as a single body.

[0026] 2, reference numeral 1f denotes the surface 1f of the seat pad 1. In the seat pad 1 according to this embodiment, a surface portion 2 up to 10 mm from the surface 1f of the seat pad 1 is cut out, and the air permeability AR1 of the surface portion 2 (hereinafter also referred to as "surface air permeability AR1") is measured in accordance with the standard of JIS K 6400. The surface air permeability AR1 is 5 cc / cm 2 / sec and greater than 25cc / cm 2 / sec or less. Below, the surface air permeability AR1 measured according to the JIS K 6400 standard is 5cc / cm 2 / sec and greater than 25cc / cm 2 The surface portion 2 where the airflow rate is less than or equal to 1 / sec is also referred to as the "airflow rate-restricting surface portion 2a."

[0027] In FIG. 2, the symbol BS denotes an interface between the surface portion 2 and the core portion 3 located more inward than the surface portion 2. In FIG. 2, the interface BS is indicated by a dashed line. In this embodiment, the surface portion 2 of the seat pad 1 is a surface portion cut out from any surface 1f of the entire surface 1f of the seat pad 1. FIG. 2 shows a cushion pad 1a. In this embodiment, the surface 1f of the cushion pad 1a is formed by a seat-side surface 1f1 (hereinafter also referred to as the "seat-side surface 1f1") and a back-side surface 1f2 (hereinafter also referred to as the "back-side surface 1f2"). That is, in the cushion pad 1a according to this embodiment, in any surface portion 2 cut out from any surface 1f of the entire surface 1f of the cushion pad 1a, the surface portion 2 becomes an airflow-restricting surface portion 2a, and its surface airflow AR1 is 5 cc / cm 2 / sec and greater than 25cc / cm 2 / sec or less.

[0028] According to the present invention, the surface portion 2 can be a surface portion cut out from a specific surface 1f of the seat pad 1, with respect to the entire surface 1f of the seat pad 1 including the cushion pad 1a and the back pad 1b. However, according to the present invention, as shown in FIG. 2, the surface portion 2 is preferably a surface portion 2 cut out from at least the seating surface 1f1 of the cushion pad 1a. More preferably, the surface portion 2 is a surface portion cut out from at least the surface 1fa on the seating region R side of the surface 1f of the cushion pad 1a (hereinafter also referred to as the "seating region side surface 1fa"). Here, the seating region R is a region to which a downward load is applied when a seat occupant sits on the seat 10. The seating region R extends in the front-to-back direction (depth direction) in addition to the left-to-right direction in the drawing. In this embodiment, as shown in FIG. 2, the seating region side surface 1fa is a smooth surface.

[0029] FIG. 3 is a diagram schematically showing the surface 1f of the seat pad 1. As shown in FIG.

[0030] 3, the surface 1f of the seat pad 1 is mostly closed areas where the cell membrane 5 is formed without being broken on the cell skeleton 4, but there are also openings 6 where the cell membrane 5 is not formed on the cell skeleton 4. Referring to FIG. 3, in this embodiment, the surface 1f of the seat pad 1 has a small proportion of the openings 6 relative to the closed areas closed by the cell membrane 5.

[0031] Generally, when the breathability of a resin foam decreases, the vibration absorption improves and the vibration transmissibility decreases. However, when the breathability decreases, there is a concern that heat may be trapped, causing stuffiness and the like.

[0032] 4 is a diagram schematically showing a surface 20f of a comparative example seat pad 20. The seat pad 20 is a resin foam obtained by supplying a molding material into a normal mold and performing foam molding.

[0033] 4, the surface 20f of the seat pad 20 is mostly occupied by the openings 6 where the cell membrane 5 is not formed. In this case, the improved breathability makes it less likely for stuffiness to occur. However, as mentioned above, when the breathability of a foamed molded body is improved, the vibration transmissibility decreases, and the vibration absorption also decreases.

[0034] In contrast, referring to Figure 3, in this embodiment, the surface portion 2 has openings 6 in the closed portion where the cell membrane 5 is formed, making it possible to achieve both thermal comfort and vibration absorption. In particular, in this embodiment, when the surface airflow rate AR1 is 5 cc / cm 2 / sec <AR1≦25cc / cm 2 / sec, discomfort caused by stuffiness due to heat buildup and discomfort caused by vibrations transmitted from the seat pad (seat) are well balanced, improving thermal comfort and vibration absorption.

[0035] Furthermore, according to this embodiment, when the core portion 3, which is located inside the surface portion 2, is cut out and the airflow rate AR2 of the core portion 3 (hereinafter also referred to as "core airflow rate AR2") is measured in accordance with the JIS K 6400 standard, the airflow rate AR2 is preferably greater than the airflow rate AR1 of the surface portion 2. In this case, heat transmitted through the surface portion 2 is efficiently released to the core portion 3, thereby further improving thermal comfort.

[0036] According to the present invention, the air permeability AR2 of the core portion 3 can be set equal to or greater than the surface air permeability AR1. In this case, the air damping effect is enhanced, thereby further improving vibration absorption.

[0037] As described above, according to the present invention, the surface portion 2 of the entire surface 1f of the seat pad 1 is made into the air permeability limiting surface portion 2a, and the surface air permeability AR1 of the entire surface 1f of the seat pad 1 is set to 5 cc / cm 2 / sec <AR1≦25cc / cm 2 / sec. Referring to Fig. 2, in this embodiment, the surface portion 2 of the entire surface 1f of the cushion pad 1a is an air-permeability limiting surface portion 2a.

[0038] However, in a seat pad, there is a trade-off between breathability and vibration absorption. Therefore, if breathability is improved for each part of the seat pad, the performance of the entire seat pad can be expected to be further improved.

[0039] In contrast, according to the present invention, the surface portion 2 at an arbitrary position on the surface 1f of the cushion pad 1a is made an air permeability-restricting surface portion 2a, and the surface air permeability AR1 of the surface 1f of the seat pad 1 is locally set to 5 cc / cm 2 / sec <AR1≦25cc / cm 2 It can limit the airflow to within / sec.

[0040] FIG. 5 is a plan view showing a seat pad according to a second embodiment of the present invention.

[0041] 5, in this embodiment, the seat pad 1 includes a cushion pad 1a, similar to the first embodiment. As shown in FIG. 5, in this embodiment, the sitting portion 21 of the cushion pad 1a is divided into a buttocks portion 22 and a knee portion 23. In this embodiment, the surface portion 2 on the seat side of the buttocks portion 22 is an airflow restriction surface portion 2a, and its surface airflow AR1 is 5 cc / cm 2 / sec <AR1≦25cc / cm 2 / sec. Furthermore, in this embodiment, the surface airflow rate AR1 of the surface portion 2 on the seat side of the under-knees 23 is greater than the surface airflow rate AR1 of the surface portion 2 on the seat side of the under-buttocks 22. In this embodiment, the under-buttocks 22 is designed to have high vibration absorption, with emphasis on vibration absorption, while the under-knees 23 is designed to have high breathability, with emphasis on breathability. As described above, according to this embodiment, the under-buttocks 22 has high vibration absorption with reduced breathability, while the under-knees 23 has higher breathability than the under-buttocks 22 while maintaining vibration absorption. This allows the functions of the cushion pad 1a to be divided and set for each portion of the cushion pad 1a.

[0042] FIG. 6 is a plan view showing a seat pad according to a third embodiment of the present invention.

[0043] 6, in this embodiment, the seat pad 1 includes a cushion pad 1a, as in the above-described embodiments. In this embodiment, the entire surface portion 2 on the seat side of the cushion pad 1a is an airflow-restricting surface portion 2a, and the entire surface airflow AR1 of the surface portion 2 on the seat side of the cushion pad 1a is 5 cc / cm 2 / sec <AR1≦25cc / cm 2 / sec. In the present embodiment, the entire seat side of the cushion pad 1a is set to have high vibration absorption, with emphasis on vibration absorption. In this way, according to the present embodiment, it is possible to increase the vibration absorption of the entire seat side of the cushion pad 1a.

[0044] Furthermore, the seat pad according to the present invention has a surface air permeability AR1 of the surface portion 2 of 5 cc / cm 2 / sec <AR1≦25cc / cm 2 The air-permeability restricted area, which is limited to an air permeability within the range of / sec, has a groove 30 that separates the air-permeability restricted area from other areas adjacent to the air-permeability restricted area, and the surface portion 2 of the air-permeability restricted area can include a surface portion of the side of the groove 30 that is continuous with the air-permeability restricted area.

[0045] Fig. 7 is a plan view schematically showing a seat pad according to a fourth embodiment of the present invention, and Fig. 8 shows a cross-sectional view taken along line BB in Fig. 7.

[0046] 7, in this embodiment, the seating portion 21 of the cushion pad 1a is divided into an under-buttocks portion 22 and a under-knee portion 23 by a groove 30. In this embodiment, the groove 30 includes grooves 31, 32, and 33. Specifically, the seating portion 21 and the side pad portion 24 are divided by groove 31. The seating portion 21 and the back pad arrangement portion 25 are divided by groove 32. Furthermore, the under-buttocks portion 22 and the under-knee portion 23 are divided by groove 33. For example, if the surface portion 2 of the seating portion 21 is an airflow restriction surface portion 2a and its surface airflow AR1 is 5 cc / cm 2 / sec <AR1≦25cc / cm 2 8, in this embodiment, when the airflow rate is in the range of 1 / sec, the surface portion 2 of the seating portion 21 includes the surface portion 2 of the side surface 31s of the groove 31 that is continuous with the seating portion 21. In this case, the inflow of air into the cushion pad 1a can be further suppressed. Therefore, according to this embodiment, the airflow rate can be suppressed and vibration absorption can be further improved.

[0047] Increasing the depth of the grooves 30 can improve vibration absorption by suppressing the flow of air in and out of the pad between the airflow restriction portion and other portions. For example, the depth of the grooves 30 can be made deeper than the suspension grooves (grooves for fixing the seat cover 11 with wires or clips) that separate each portion. Specific examples of the groove depth include a distance between the surface 1f of the seat pad 1 and the groove bottom that is 10 mm or less, more preferably 5 mm or less. In this embodiment, the depths of the grooves 31, 32, and 33 are constant throughout the entire groove 30. In this embodiment, the widths of the grooves 31, 32, and 33 are constant throughout the entire groove 30.

[0048] In the second to fourth embodiments, the rear surface 1f2 of the cushion pad 1a is configured such that the surface portion 2 of the rear surface 1f2 of the cushion pad 1a is the air permeability-restricting surface portion 2a, and the surface air permeability AR1 is set to 5 cc / cm 2 / sec <AR1≦25cc / cm 2 / sec, but the airflow rate can be outside this range.

[0049] [Seat pad manufacturing method] Next, a method for manufacturing a seat pad according to this embodiment will be described with reference to the drawings.

[0050] The method for manufacturing a seat pad according to one embodiment of the present invention is a method for manufacturing a seat pad, in which a molding material M1 is supplied into a mold 100 and foam-molded to obtain a seat pad 1.

[0051] Fig. 9A is a cross-sectional view schematically showing a molding die 100 usable in a method for manufacturing a seat pad according to one embodiment of the present invention before clamping, and Fig. 9B is a cross-sectional view schematically showing the molding die 100 of Fig. 9A in a clamped state.

[0052] Referring to FIG. 9B, reference numeral 100 denotes a molding die that can be used in the manufacturing method of the seat pad 1. In this embodiment, the molding die 100 is a mold for obtaining the cushion pad 1a among molding dies for obtaining the seat pad 1. An inner surface 100f of the molding die 100 forms a cavity into which a molding material M1 is supplied to perform foam molding. The inner surface 100f of the molding die 100 is covered with a resin M2. In this embodiment, a molding die in which the entire inner surface 100f of the molding die 100 is covered with the resin M2 is used as the molding die 100. For example, PS (polystyrene) or PE (polyethylene) can be used as the resin M2. Furthermore, HDPE (high density polyethylene) or LDPE (low density polyethylene) can be used as the PE. In this embodiment, HDPE is used as the resin M2.

[0053] 9A, in this example, the molding die 100 includes an upper die 101 and a lower die 102. The inner surface 100f of the molding die 100 is formed by the inner surface 101f of the upper die 101 and the inner surface 101f of the lower die 102. In this example, the resin M2 is formed by a resin sheet. In this embodiment, the upper die 101 forms the back surface 1f2 of the cushion pad 1a. In this embodiment, the lower die 102 forms the seat surface 1f1 of the cushion pad 1a.

[0054] A method for manufacturing a seat pad according to one embodiment of the present invention is outlined as follows.

[0055] [Mold placement process] First, as shown in Fig. 9A, inner surface 101f of upper mold 101 and inner surface 101f of lower mold 102 are each covered with resin M2. In this embodiment, inner surface 101f of upper mold 101 and inner surface 101f of lower mold 102 are each covered with a resin sheet made of resin M2. Next, as shown in Fig. 9B, upper mold 101 and lower mold 102 are brought together to form the cavity covered with resin M2 inside molding mold 100.

[0056] [Foam molding process] Next, as shown in FIG. 9B, molding material M1 is injected into the mold 100 covered with resin M2, and the molding material M1 is heated and foamed. Thereafter, the mold 100 is clamped, and foam molding is performed inside the mold 100. The molding material M1 is a foamed resin. The foamed resin is preferably soft polyurethane. An example of the molding material M1 is soft foamed polyurethane, which is obtained by mixing a foaming agent with a soft polyurethane resin. However, according to the present invention, various foamed resins can be used as the molding material M1.

[0057] [Mold opening process] After the foam molding inside the mold 100 is completed, the mold 100 is opened to separate the upper mold 101 and the lower mold 102. This makes it possible to obtain a seat pad 1 with a cell membrane remaining rate of 92% or more on the surface 1f.

[0058] In this way, by using a molding die 100 whose inner surface 100f is covered with resin M2 as the molding die 100, the seat pad 1 can be easily obtained by the simple process of simply covering the inner surface 100f of the molding die 100 with resin M2.

[0059] As described above, the manufacturing method according to this embodiment uses molding die 100 in which inner surface 100f of molding die 100 is entirely covered with resin M2.

[0060] On the other hand, according to the manufacturing method of the present invention, a molding die 100 can be used in which the inner surface of the seating surface side of the cushion pad 1a is locally coated with the resin M2.

[0061] FIG. 10 is a cross-sectional view that schematically shows a mold clamped state of a molding die 100 that can be used in a manufacturing method for obtaining the cushion pad 1a of FIG.

[0062] As described above, in this embodiment, the molding die 100 is a molding die for obtaining the cushion pad 1a. In the molding die 100 shown in Fig. 10, the inner surface of the cushion pad 1a on the seating surface side is locally coated with the resin M2. By using such a molding die 100, it is possible to obtain the cushion pad 1a having the grooves 30 formed therein, as shown in Fig. 7, for example.

[0063] In particular, as shown in Fig. 10, molding die 100 has protrusions 103 that partition inner surface 100f of molding die 100 and are coated with resin M2. In this embodiment, resin M2 covers side surface 103f of protrusion 103. Side surface 103f of protrusion 103 is continuous with inner surface 100f of molding die 100, which is coated with resin M2. This makes it possible to obtain cushion pad 1a that is partitioned by grooves 30 as shown in Figs. 7 and 8. Furthermore, by changing the arrangement of resin M2 in molding die 100 of Fig. 10, it is possible to obtain cushion pad 1a as shown in Fig. 5, for example.

[0064] FIG. 11 is a cross-sectional view schematically showing a mold in a clamped state that can be used in a method for producing the seat pad shown in FIG.

[0065] As described above, in this embodiment, the molding die 100 is a molding die for obtaining the cushion pad 1a. In the molding die 100 of FIG. 11, the inner surface of the cushion pad 1a on the seating surface side is also locally coated with the resin M2. In this embodiment, the molding die 100 is such that the entire inner surface of the cushion pad 1a on the seating surface side is coated with the resin M2. By using such a molding die 100, for example, a cushion pad 1a as shown in FIG. 6 can be obtained.

[0066] [Test Results] Next, test results for seat pads obtained by using different resins M2 as the resin M2 coated on the inner surface 100f of the mold 100 are shown below.

[0067] FIG. 12 is a diagram showing the vibration transmissibility VR1 of the seat pad 1 according to this embodiment and the vibration transmissibility VR2 of the seat pad 20 as the comparative example 1. As shown in FIG.

[0068] 12, symbol VR1 denotes the vibration transmissibility of the seat pad 1 according to this embodiment, measured in accordance with the JASO B-407 standard. Symbol VR2 denotes the vibration transmissibility of the seat pad 20 of Comparative Example 1, also measured in accordance with the JASO B-407 standard.

[0069] In FIG. 12, the test results for vibration transmissibility VR1 obtained using the seat pad 1 are shown by a solid line, and the test results for vibration transmissibility VR2 obtained using the seat pad 20 are shown by a dashed line.

[0070] Referring to FIG. 12, the resonance magnification factor (peak value of the vibration transmission rate VR1 of the seat pad 1) RM1 of the seat pad 1 is suppressed to a value lower than the resonance magnification factor (peak value of the vibration transmission rate VR2 of the seat pad 20) RM2 of the seat pad 20. Therefore, it can be seen from FIG. 12 that the seat pad 1 according to the present embodiment has better vibration absorption than the seat pad 20 of Comparative Example 1.

[0071] Next, FIG. 13 is a graph showing the relationship between the surface ventilation rate AR1 of the seat pad and the resonance magnification factor RM of the seat pad.

[0072] FIG. 13 shows the relationship between the surface ventilation rate AR1 and the resonance magnification factor RM of the seat pad obtained by the mold 100 coated with different resins M2.

[0073] Referring to FIG. 13, as the surface ventilation rate AR1 of the seat pad decreases, the resonance magnification factor RM also tends to decrease. In particular, from FIG. 13, at the boundary of the surface ventilation rate AR1 = 25 cc / cm 2 / sec, the resonance magnification factor RM is rapidly suppressed. Therefore, it can be seen from FIG. 13 that for a seat pad with AR1 ≤ 25 cc / cm 2 / sec like the seat pad 1 according to the present embodiment, the vibration absorption can be effectively enhanced while ensuring the ventilation rate.

[0074] More specifically, when 25 cc / cm 2 / sec < AR1, the resonance magnification factor RM exceeds 4.5. This test result is from two types of seat pads: the seat pad 20 as Comparative Example 1, which was foam molded without coating the inner surface 100f of the mold 100 with the resin M2, and the seat pad foam molded with the inner surface 100f of the mold 100 coated with PP (polypropylene) as the resin M2.

[0075] In contrast, when AR1 ≤ 25 cc / cm 2 / sec, the resonance magnification RM falls below 4.5. These test results are for three types of seat pads 1: a seat pad 1 according to this embodiment (hereinafter also referred to as "HDPE-molded seat pad 1") in which the inner surface 100f of the mold 100 is coated with HDPE (high-density polyethylene) as the resin M2 and foam-molded; a seat pad 1 according to another embodiment of the present invention (hereinafter also referred to as "LDPE-molded seat pad 1") in which the inner surface 100f of the mold 100 is coated with LDPE (low-density polyethylene) as the resin M2 and foam-molded; and a seat pad 1 according to another embodiment of the present invention (hereinafter also referred to as "PS-molded seat pad 1") in which the inner surface 100f of the mold 100 is coated with PS (polystyrene) as the resin M2 and foam-molded.

[0076] Also, referring to FIG. 13, according to the three types of seat pads 1, the surface air permeability AR of the seat pad is AR1<5 cc / cm 2 / sec, the surface air permeability AR1 of the seat pad is ensured and the resonance magnification RM tends to be rapidly suppressed.

[0077] More specifically, in the two types of seat pads, the HDPE molded seat pad 1 according to this embodiment and the PS molded seat pad 1 according to another embodiment of the present invention, AR1=5 cc / cm 2 / sec, the resonance magnification RM is suppressed to 3.0 to 3.5. Also, the LDPE molded seat pad 1 according to this embodiment has an AR1 of 5 cc / cm 2 / sec, the resonance magnification VR may be suppressed to 3.0 to 3.5. In particular, in the case of the HDPE molded seat pad 1 according to this embodiment, the resonance magnification RM is suppressed most effectively around 3.0.

[0078] As is clear from the above test results, the method for manufacturing a seat pad according to the present invention preferably uses a mold 100 whose inner surface 100f is coated with high-density polyethylene. In this case, the resonance magnification RM of the seat pad 1 can be most effectively reduced. Therefore, in this case, vibration absorption is further improved.

[0079] Furthermore, as is clear from the above test results, the method for manufacturing a seat pad according to the present invention preferably uses a mold 100 in which the inner surface 100f of the mold 100 is coated with polystyrene. In this case, the resonance magnification RM of the seat pad can be effectively reduced, similar to the case in which a mold in which the inner surface 100f of the mold 100 is coated with high-density polyethylene is used. Therefore, in this case, vibration absorption is further improved. In particular, when a mold coated with HDPE is used, the resonance magnification RM is further reduced, i.e., vibration absorption is further improved.

[0080] Furthermore, as is clear from the above test results, it is preferable that the method for manufacturing a seat pad according to the present invention uses a mold 100 whose inner surface 100f is coated with low-density polyethylene as the mold 100. In this case as well, vibration absorption is further improved.

[0081] The following table shows the resonant frequency, resonant magnification, and surface airflow rate, along with the membrane remaining rate (%), of each seat pad obtained by foam molding using a molding die in which the inner surface 100f of the molding die 100 is coated with resin M2. PP-1 and PP-2 are polypropylenes (PP-1 to PP-2), respectively. Here, "normal" refers to the case in which foam molding is performed without coating the inner surface 10f of the molding die 100 with resin M2. In other words, "normal" refers to the seat pad 20 of Comparative Example 1. The membrane remaining rate (%) is the remaining rate of the cell membrane 5 on the surface 1f of the seat pad 1 relative to a given area of ​​the surface 1f. Here, the given area is the area of ​​a rectangle measuring 80 mm long x 80 mm wide.

[0082] [Table 1]

[0083] Referring to Table 1 above, in the manufacturing method of the seat pad 1, if high density polyethylene is used as the resin M2 that coats the inner surface 100f of the mold 100, the remaining rate of the cell membrane becomes 97.5% or more, and the surface air permeability AR1 becomes 5 cc / cm 2 / sec <AR1≦25cc / cm 2 / sec is satisfied. It is also clear that the surface air permeability AR1 is suppressed compared to when polypropylene or low-density polyethylene is used as the resin M2 that coats the inner surface 100f of the molding die 100. In other words, the air damping effect, i.e., vibration absorption, is best when a molding die 100 is used in which high-density polyethylene is used as the resin M2 that coats the inner surface 100f of the molding die 100.

[0084] Furthermore, referring to Table 1 above, in the manufacturing method of the seat pad 1, if polystyrene is used as the resin M2 that coats the inner surface 100f of the mold 100, the remaining rate of the cell membrane will be 97.5% or more, similar to high-density polyethylene, and the surface air permeability AR1 will be 5 cc / cm or more. 2 / sec <AR1≦25cc / cm 2 / sec is satisfied. Therefore, in this case too, the vibration absorption is the best.

[0085] Furthermore, referring to Table 1 above, in the manufacturing method of the seat pad 1, if low-density polyethylene is used as the resin M2 that coats the inner surface 100f of the mold 100, the remaining rate of the cell membrane becomes 95% or more, and the surface air permeability AR1 becomes 5 cc / cm 2 / sec <AR1≦25cc / cm 2 / sec is satisfied. It is also clear that the surface air permeability AR1 is reduced compared to when polypropylene is used as the resin M2 that coats the inner surface 100f of the molding die 100. In other words, when low-density polyethylene is used as the resin M2 that coats the inner surface 100f of the molding die 100, the air damping effect, i.e., vibration absorption, is better than when polypropylene is used.

[0086] The above has been a description of exemplary embodiments of the present invention, and various modifications can be made without departing from the scope of the claims. Furthermore, the various configurations employed in the above-described embodiments can be appropriately substituted for each other. [Explanation of symbols]

[0087] 1: seat pad, 2: surface portion, 2a: air permeability limiting surface portion, 3: core portion, 1f: surface of seat pad (surface), 4: skeleton, 5: cell membrane, 6: opening, 100: molding die, 100f: inner surface of molding die, 101: upper die, 101f: inner surface of upper die, 102: lower die, 102f: inner surface of lower die, M1: molding material, M2: resin

Claims

1. When a surface portion up to 10 mm from the surface of the seat pad is cut out and the air permeability of the surface portion is measured in accordance with the standard of JIS K 6400, the air permeability is greater than 5 cc / cm2 / sec and less than or equal to 25 cc / cm2 / sec, The seat pad includes a cushion pad, The seating portion of the cushion pad is defined by a buttocks area and a knee area, The air permeability of the surface portion of the seat side of the lower buttocks is greater than 5 cc / cm2 / sec and is within a range of 25 cc / cm2 / sec or less, The seat pad has a larger air permeability of the surface portion in the lower knee area than that of the surface portion in the lower buttock area.

2. In addition, a core portion inside the surface portion is cut out, and the air permeability of the core portion is measured according to the JIS standard.

2. The seat pad according to claim 1, wherein the air permeability measured in accordance with the K 6400 standard is greater than the air permeability of the surface portion.

3. a groove separating an airflow restriction portion, in which the airflow amount of the surface portion is restricted to the range of airflow amount set forth in claim 1, from another portion adjacent to the airflow restriction portion; The seat pad according to claim 1 or 2, wherein the surface portion of the airflow restriction portion includes a surface portion of a side surface of the groove that is continuous with the airflow restriction portion.

4. A method for manufacturing a seat pad according to claim 1 or 2, by supplying a molding material into a mold and performing foam molding, comprising: the molding die is a molding die for obtaining a cushion pad, A method for manufacturing a seat pad using, as the molding die, a molding die in which the inner surface of the seat side of the cushion pad is locally coated with polystyrene or polyethylene.

5. A method for manufacturing a seat pad according to claim 1 or 2, by supplying a molding material into a mold and performing foam molding, comprising: the molding die is a molding die for obtaining a cushion pad, A method for manufacturing a seat pad using, as the molding die, a molding die in which the entire inner surface of the seat side of the cushion pad is covered with polystyrene or polyethylene.

6. 6. The method for manufacturing a seat pad according to claim 4 or 5, wherein the mold has a protrusion that divides the inner surface of the mold and is covered with the polystyrene or the polyethylene, and the polystyrene or the polyethylene covers a side surface of the protrusion.

7. The method for manufacturing a seat pad according to any one of claims 4 to 6, wherein the mold used is a mold whose inner surface is covered with high-density polyethylene.

8. The method for manufacturing a seat pad according to any one of claims 4 to 6, wherein the mold used is a mold whose inner surface is covered with polystyrene.

9. The method for manufacturing a seat pad according to any one of claims 4 to 6, wherein the mold used is a mold whose inner surface is covered with low-density polyethylene.

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