Elastic body and method for manufacturing elastic body

Abstract

To provide an elastic body capable of reducing defects generated in the vicinity of a linear member, and a method for manufacturing the elastic body.SOLUTION: The elastic body includes a main body made of soft polyurethane foam, a linear member embedded near a back surface of the main body, and an elastic porous body embedded between the back surface and the linear member, and a length between the back surface of the main body and the linear member at a portion where the porous body is embedded is equal to or less than 20mm. A method for manufacturing an elastic body includes a placing step of placing a porous body made of an elastic body between a forming surface of a forming die and a linear member, and an injecting step of injecting a material of a soft polyurethane foam into the forming die in which the linear member and the porous body are placed, wherein a length between a portion of the linear member where the porous body is placed and the forming surface is equal to or less than 20mm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an elastic body including a body made of flexible polyurethane foam and a method for producing the same. [Background technology]

[0002] In a foam molded body (elastic body) including a molded body main body (main body) made of soft polyurethane foam, a linear skin material fastening member (linear member) is embedded by insert molding along the bottom of a hanging groove provided on the surface of the main body, and the skin is fastened to the linear member via fastening devices such as hooks and hog rings attached to the skin, and the skin is attached to the main body. Since embedding linear members in the main body can make the elastic body less flexible, the prior art ensures the flexibility of the elastic body by replacing the linear members with four L-shaped linear members such as metal wires and connectors made of thermoplastic elastomer or the like that connect adjacent linear members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-102859 Summary of the Invention [Problem to be solved by the invention]

[0004] In the prior art, to manufacture an elastic body with a linear member embedded near the back surface of the body, the linear member is attached to the upper part of a mold, and then a flexible polyurethane foam raw material is injected into the mold and foamed to form the body. If the flow of the expanding raw material inside the mold is obstructed by the linear member, a problem occurs in that part of the body corresponding to the area between the linear member and the upper part is chipped off.

[0005] The present invention has been made to solve this problem, and has as its object to provide an elastic body and a method for manufacturing an elastic body that can reduce defects that occur near linear members. [Means for solving the problem]

[0006] The first aspect for achieving this object is an elastic body comprising a main body made of soft polyurethane foam, a linear member embedded near the back surface of the main body, and an elastic porous body embedded between the back surface and the linear member, wherein the distance between the back surface of the main body and the linear member at the part where the porous member is embedded is 20 mm or less.

[0007] In the second aspect, in the first aspect, the porous body includes a slit provided on the outer periphery of the porous body, the porous body is arranged on the linear member along the slit, and the outer periphery of the porous body is positioned around the linear member.

[0008] In the third embodiment, in the second embodiment, the portion where the cut line intersects with the outer periphery of the porous body contacts a portion of the main body other than the back surface of the main body.

[0009] In a fourth aspect, the porous body of the second or third aspect includes a notch provided on the outer periphery of the porous body away from the slit, and the portion where the notch intersects with the outer periphery of the porous body is non-parallel to the portion where the slit intersects with the outer periphery of the porous body.

[0010] The fifth aspect is a method for producing an elastic body in which raw material for a flexible polyurethane foam is injected into a mold in which a linear member is placed and foamed, a main body made of flexible polyurethane foam is molded in the shape of the molding surface of the mold, and the linear member is embedded in the main body by insert molding, the method comprising an arrangement step of placing an elastic porous body between the linear member and the molding surface, and an injection step of injecting raw material into the mold in which the linear member and porous body are placed, and the distance between the part of the linear member in which the porous body is placed and the molding surface is 20 mm or less. [Effects of the Invention]

[0011] According to the present invention, an elastic porous body is embedded in the area where defects are likely to occur between the back surface of the main body made of soft polyurethane foam and the linear member, thereby reducing defects that may occur near the linear member. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a cross-sectional view of an elastic body according to an embodiment. [Figure 2] FIG. [Figure 3] 3(a) is an enlarged cross-sectional view of the mold showing the part indicated by IIIa in FIG. 2, (b) is a perspective view of the upper mold in which the linear members and the porous body are arranged, and (c) is a cross-sectional view of the porous body. [Figure 4] (a) is a side view of a porous body in a modified example, (b) is a cross-sectional view of the porous body along line IVb-IVb, (c) is a cross-sectional view of the porous body along line IVc-IVc, and (d) is a side view of a linear member in which a porous body is arranged. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a cross-sectional view of an elastic body 10 according to one embodiment. The elastic body 10 comprises a main body 11, a linear member 14 embedded in the main body 11, and a porous body 15. In this embodiment, the elastic body 10 is described using a pad (seat cushion) that supports the user's buttocks as an example, but there are no limitations on the uses of the elastic body 10. Other uses of the elastic body 10 include a pad (seat back) used as a backrest for the user, an armrest for a sofa or chair, or a footrest. A skin (not shown) made of woven or knitted fabric, leather, or the like is placed over the elastic body 10 for decoration or to provide comfort to the user.

[0014] The main body 11 is an elastic member made of soft polyurethane foam. The main body 11 includes a front surface 12 on which the user's buttocks rest, and a back surface 13 located opposite the front surface 12. The linear member 14 is a thin, elongated member made of metal or synthetic resin, and is embedded in the main body 11 along and near the back surface 13 of the main body 11 for the purposes of attaching a cover (not shown) to the elastic body 10, securing (reinforcing) the outer shape of the elastic body 10, and attaching the elastic body 10 to a vehicle body (not shown).

[0015] The porous body 15 is an elastic member having numerous small air bubbles. The porous body 15 is exemplified by a foam made of a soft synthetic resin. Examples of materials for the porous body 15 include thermoplastic resins such as polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polypropylene, polyethylene, polyvinyl chloride, and polyvinyl alcohol; thermosetting resins such as polyurethane, phenolic resin, urea resin, epoxy resin, acrylic resin, and silicone resin; and cellulose-based materials such as acetyl cellulose and viscose. The air bubbles in the porous body 15 may be either closed or open, but open cells are preferred. The porous body 15 is disposed in a portion of the main body 11, including the portion between the rear surface 13 and the linear member 14.

[0016] In this embodiment, the cross section of the porous body 15 is circular, and a slit 17 extending toward the center of the porous body 15 is provided on the outer periphery 16 of the porous body 15. The linear member 14 is disposed within the slit 17. The porous body 15 is embedded in the main body 11 by insert molding, and there is a slight distance between the outer periphery 16 of the porous body 15 and the back surface 13 of the main body 11. The portion where the slit 17 intersects with the outer periphery 16 of the porous body 15 is in contact with the main body 11.

[0017] FIG. 2 is a cross-sectional view of a molding die 20 for molding the main body 11. The molding die 20 includes a lower die 21 and an upper die 22 that covers the lower die 21. The front surface 12 of the main body 11 (see FIG. 1) is formed in the shape of a molding surface 23a of the lower die 21, and the back surface 13 of the main body 11 is formed in the shape of a molding surface 23b of the upper die 22. The upper die 22 is provided with a plurality of fixing portions 24 that fix the linear members 14 along the molding surface 23b of the upper die 22. The fixing portions 24 have, for example, walls that protrude from the molding surface 23b toward the lower die 21. If the linear members 14 are made of a material that is attracted to a magnet, the linear members 14 will be attracted to the magnets embedded in the fixing portions 24 and fixed along the walls.

[0018] When manufacturing the elastic body 10, first, the linear member 14 with the porous body 15 arranged therein is attached to the upper mold 22 by the fixing part 24 with the mold 20 open. Next, the raw material 25 (liquid) of the flexible polyurethane foam is poured into the lower mold 21, and then the upper mold 22 is placed over the lower mold 21 and the mold is closed. The raw material 25 expands while reacting in the mold 20, and the main body 11 (see Figure 1) is formed in the shape of the molding surfaces 23a, 23b, with the linear member 14 and porous body 15 embedded in the main body 11. After the raw material 25 has solidified, the upper mold 22 is opened and demolded to obtain the elastic body 10 in which the linear member 14 and porous body 15 are insert-molded into the main body 11.

[0019] 3(a) is a cross-sectional view of the molding die 20, enlarging the portion indicated by IIIa in FIG. 2. The distance D between the portion of the linear member 14 where the porous body 15 is arranged and the molding surface 23b is 20 mm or less, and more preferably 15 mm or less. In this embodiment, there is a gap between the outer periphery 16 of the porous body 15 and the molding surface 23b of the upper die 22. The portion where the slit 17 intersects with the outer periphery 16 of the porous body 15 faces the lower die 21 (see FIG. 2), and the linear member 14 is located between the portion where the slit 17 intersects with the outer periphery 16 of the porous body 15 and the upper die 22.

[0020] FIG. 3(b) is a perspective view of the upper mold 22 in which the linear member 14 and the porous body 15 are arranged. FIG. 3(c) is a cross-sectional view of the porous body 15 before it is attached to the linear member 14. The porous body 15 is cylindrical, and a slit 17 runs from one end of the porous body 15 to the other. The portion where the slit 17 intersects with the outer periphery 16 of the porous body 15 is a finite straight line extending from one end of the porous body 17 to the other, and the center of the cross section of the porous body 15 is parallel to the center line of the porous body 15. When the porous body 15 is attached to the linear member 14, the linear member 14 is pressed into the slit 17 of the porous body 15.

[0021] The depth of the slits 17 from the outer periphery 16 of the porous body 15 is approximately 1 / 3 to 2 / 5 of the thickness of the porous body 15. The porous body 15 is arranged on the linear member 14 along the slits 17. The thickness of the linear member 14 is, for example, 2 mm to 3 mm. The length of the porous body 15 along the linear member 14 is, for example, 50 mm or more. The thickness of the porous body 15 is, for example, 2 to 5 times the thickness of the linear member 14. The thickness of the porous body 15 is, for example, 10 mm or more. This is to ensure the amount of raw material for the flexible polyurethane foam that permeates the porous body 15.

[0022] The porous body 15 can be made by punching a synthetic resin foam into a columnar shape or by cutting a columnar shape from a foam. The 40% hardness of the porous body 15 is 200N / 314cm 2 from 350N / 314cm 2 This is to ensure the hardness of the elastic body 10 in which the porous body 15 is embedded in the main body 11. The 40% hardness is determined by measuring the hardness of the foam material of the porous body 15 using a method in accordance with JIS K6400-2:2012 Method A.

[0023] The air permeability of the porous body 15 is 30 cc / cm 2 / sec or more, for example, in order to facilitate absorption of the raw materials of the flexible polyurethane foam and gas into the porous body 15. The air permeability can be determined by measuring the air permeability of the foam of the material of the porous body 15 by a method conforming to JIS K6400-7:2012 Method B.

[0024] The porous body 15 is fixed to the linear member 14 by friction between the linear member 14 pressed into the slits 17 and the porous body 15. Because the porous body 15 has slits 17 that connect from one end to the other, the porous body 15 can be easily positioned between the molding surface 23b of the upper mold 22 and the linear member 14 along the linear member 14 by the friction force generated by the elasticity of the porous body 15.

[0025] The raw material 25 injected into the lower mold 21 (see Figure 2) to form the main body 11 (see Figure 1) expands as it reacts, its viscosity gradually increasing, and it turns creamy as it reaches the upper mold 22. As the raw material expands, the gas inside the molding mold 20 is expelled from the joint (parting) between the upper mold 22 and the lower mold 21, but as the reaction of the raw material nears its end, the linear members 14 positioned near the molding surface 23b of the upper mold 22 and the gas remaining near the linear members 14 become obstacles to the expansion of the raw material, making defects more likely to occur on the linear members 14.

[0026] In contrast, according to this embodiment, the porous body 15 is disposed between the linear members 14 and the molding surface 23b, so that the creamy ingredients spread as they soak into the air bubbles in the porous body 15. The ingredients soak into the porous body 15, bonding the porous body 15 to the main body 11. If the porous body 15 is breathable, the porous body 15 will absorb the gas. Because the linear members 14 are buried between the porous body 15 and the main body 11, defects that may occur near the linear members 14 can be reduced.

[0027] When the raw material penetrates and solidifies into the gap between the outer periphery 16 of the porous body 15 and the molding surface 23b of the upper mold 22, completely filling the gap, the porous body 15 will not appear on the back surface 13 of the main body 11 (see FIG. 1). On the other hand, if there is a portion of the gap between the outer periphery 16 of the porous body 15 and the molding surface 23b of the upper mold 22 where the raw material does not penetrate, part of the porous body 15 will appear on the back surface 13 of the main body 11. Since the porous body 15 is arranged so that the linear member 14 is located between the upper mold 22 and the portion where the slit 17 intersects with the outer periphery 16 of the porous body 15, it is possible to prevent the slit 17 from appearing on the back surface 13 of the main body 11 when part of the porous body 15 appears on the back surface 13 of the main body 11.

[0028] The porous body 15 may be disposed in a portion of the linear member 14 where defects are likely to appear in the main body 11, or the porous body 15 may be disposed over the entire linear member 14. A porous body 15 manufactured to match the length of the linear member 14 may be disposed on the linear member 14, or a plurality of porous bodies 15 that are shorter than the length of the linear member 14 may be arranged side by side and disposed on the linear member 14.

[0029] Fig. 4(a) is a side view of a porous body 26 in a modified example. Fig. 4(b) is a cross-sectional view of the porous body 26 taken along line IVb-IVb. Fig. 4(c) is a cross-sectional view of the porous body 26 taken along line IVc-IVc. Fig. 4(d) is a side view of a linear member 31 in which the porous body 26 is arranged. The porous body 26 has notches 30 formed therein, and is mainly arranged in portions where the linear member 31 bends in a bow or hook shape or intersects in a T-shape or a cross shape.

[0030] The porous body 26 is an elastic cylindrical member containing many small bubbles. A slit 29 connecting the outer periphery 27 and inner periphery 28 of the porous body 26 is provided along the length of the porous body 26 (left-right direction in FIG. 4(a)). The length of the porous body 26 is, for example, 50 mm or more. The portion where the slit 29 intersects with the outer periphery 27 of the porous body 26 is a finite straight line extending from one end of the porous body 26 to the other, and is parallel to the center line of the porous body 26 along which the centers of the cross sections of the porous body 26 are connected.

[0031] The thickness of the linear member 31 provided inside the inner periphery 28 of the porous body 26 is, for example, 4 mm to 10 mm. Because the porous body 26 has the inner periphery 28, the porous body 26 can be placed on the thick linear member 31. The width of the inner periphery 28 of the porous body 26 is, for example, 0.9 to 1.0 times the thickness of the linear member 31. This is to reduce the gap between the inner periphery 28 of the porous body 26 and the outer periphery of the linear member 31. The distance between the outer periphery 27 and the inner periphery 28 of the porous body 26 (the thickness of the porous body 26) is, for example, 5 mm to 11 mm. This is to ensure the amount of raw material of the flexible polyurethane foam that permeates the porous body 26.

[0032] The notch 30 is provided on the outer periphery 27 of the porous body 26, away from the slit 29, and connects the outer periphery 27 and the inner periphery 28. In this embodiment, one notch 30 that is triangular when viewed from the side of the porous body 26 is provided at a position that bisects the length of the porous body 26. The portion where the notch 30 intersects with the outer periphery 27 of the porous body 26 is an arc extending in the circumferential direction of the porous body 26. In other words, the portion where the notch 30 intersects with the outer periphery 27 of the porous body 26 is non-parallel to the portion where the slit 29 intersects with the outer periphery 27 of the porous body 26. Because the porous body 26 has the notch 30, the notch 30 is arranged in a bent state facing outward at the bent portion of the linear member 31.

[0033] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention.

[0034] In the embodiment, the porous body 15 is columnar and the porous body 26 is cylindrical. That is, the porous bodies 15 and 26 have a circular cross-sectional outer shape, but this is not necessarily limited to this. It is of course possible for the porous bodies 15 and 26 to have a polygonal cross-sectional shape such as a triangle or a rectangle, or an elliptical cross-sectional outer shape.

[0035] In the embodiments, the porous bodies 15, 26 having the slits 17, 29 are disposed on the linear members 14, 31, but this is not necessarily limited to this. It is of course possible to wrap a sheet-like porous body around the linear members 14, 31, or to place the porous body on the portion of the linear members 14, 31 facing the molding surface 23b of the upper mold 22, and then fix the porous body with a pin or glue it so that it does not come off the linear members 14, 31. In this case, too, the porous body is disposed between the linear members 14, 31 and the molding surface 23b of the upper mold 22, so that defects in the main body 11 that may occur near the linear members 14, 31 can be reduced.

[0036] Although not explained in the embodiment, it is of course possible to mold the main body 11 after attaching the linear members 14, 31 with the porous bodies 15, 26 arranged thereon to a so-called three-part molding die 20 having a core provided in the upper die 22.

[0037] In the embodiment, a case where there is a gap between the outer periphery 16 of the porous body 15 and the molding surface 23b of the upper mold 22 has been described, but this is not necessarily limited to this. It is of course possible to mold the main body 11 in a molding die 20 in which the outer periphery 16 of the porous body 15 and the molding surface 23b of the upper mold 22 are in contact. In this case, part of the outer periphery 16 of the porous body 15 appears on the back surface 13 of the main body 11, but because the porous body 15 is bonded to the main body 11, defects in the main body 11 can be reduced.

[0038] When the outer periphery 16 of the porous body 15 and the molding surface 23b of the upper mold 22 are in contact with each other, the portion where the slit 17 intersects with the outer periphery 16 of the porous body 15 is not in contact with the molding surface 23b. Preferably, the porous body 15 is arranged so that the linear member 14 is located between the portion where the slit 17 intersects with the outer periphery 16 of the porous body 15 and the upper mold 22. If the slit 17 of the porous body 15 embedded in the main body 11 appears on the back surface 13 of the main body 11, the slit 17 of the porous body 15 may open when the main body 11 is deformed, revealing the linear members 14, 31. Therefore, the slit 17 of the porous body 15 is designed not to appear on the back surface 13 of the main body 11.

[0039] In the embodiment, a case has been described in which the porous body 26 has one triangular notch 30 when viewed from the side, but this is not necessarily limited to this. The shape of the notch 30 when viewed from the side of the porous body 26 can be a rectangle or a finite straight line in addition to a triangle. It is of course possible to provide multiple notches 30 in the porous body 26 at intervals along the length of the porous body 26. A porous body 26 having multiple notches 30 is advantageous when attaching the porous body 26 to a linear member that is curved in a bow shape. [Explanation of symbols]

[0040] 10 Elastic Body 11 Main unit 13 Back side 14,31 Linear members 15,26 Porous materials 16,27 perimeter 17,29 Break 20 mold 23b Molding surface 25 Raw materials 30 cuts D distance

Claims

1. a main body made of soft polyurethane foam; a linear member embedded near the rear surface of the main body; an elastic porous body embedded between the back surface and the linear member, An elastic body, wherein the distance between the back surface of the main body in the portion where the porous body is embedded and the linear member is 20 mm or less.

2. the porous body includes a cut provided on the outer periphery of the porous body, the porous body is disposed on the linear member along the cut line, 2. The elastic body according to claim 1, wherein the outer periphery of the porous body is positioned around the linear member.

3. 3. The elastic body according to claim 2, wherein the portion where the cut line intersects with the outer periphery of the porous body is in contact with the main body other than the back surface.

4. the porous body includes a notch provided on the outer periphery of the porous body apart from the cut line, 4. The elastic body according to claim 2, wherein a portion where the incision intersects with the outer periphery of the porous body is non-parallel to a portion where the slit intersects with the outer periphery of the porous body.

5. A method for producing an elastic body having linear members embedded in the main body, comprising: injecting a raw material for a flexible polyurethane foam into a mold having linear members arranged therein, foaming the raw material, and molding a main body made of the flexible polyurethane foam in the shape of a molding surface of the mold; a positioning step of positioning an elastic porous body between the linear member and the molding surface; an injection step of injecting the raw material into the mold in which the linear member and the porous body are arranged, The method for manufacturing an elastic body, wherein the distance between the portion of the linear member where the porous body is arranged and the molding surface is 20 mm or less.

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