JP2016112222A - Cushion body - Google Patents

Abstract

Provided is a cushioning body that has excellent cushioning properties when sitting or lying on a person, can be reduced in weight, and has excellent recyclability. A load of a seated person or a supine person comprising a synthetic resin foam having a bending deflection amount measured in accordance with a method described in JIS K7221-2: 2006 of 20 mm or more and a pressing force at the time of 20 mm deflection of 2 to 100 N. A plurality of rod-like or single or plural plate-like supports 2 that are bent and deformed upon receiving; Bending deformation portions 4 that are bent by a load applied to the support body are formed at both end portions 15 in the longitudinal direction N of the support body 2 where 2 is a support point side during bending deformation. [Selection] Figure 4

Description

  The present invention is used as a component for vehicle seats such as vehicles, ships and airplanes, sofas, chairs, cushions, beds, sleepers, mattresses, mattresses, pillows, mats, etc., used when a person is sitting or lying on the back The present invention relates to a cushion body that promotes weight reduction, is highly recyclable, and is comfortable to sit and sleep.

  In general, a cushion body has a structure in which a soft cushioning material such as urethane foam is placed on a structure that ultimately supports the pressing of a wire or a plate-like support stretched on a frame, and the entire surface is covered with a skin. Have. Also, cushions, bed mattresses, and the like themselves do not contain a structure, but they are generally used on a structure that can support the pressure of the human body, such as a floor or a frame of a bed.

  In general cushion bodies, vibrations and impacts applied to the cushion material are mainly reaction forces when a soft cushion material such as urethane foam interposed between the structure and the skin is bent in the compression direction. It was alleviated by restoring force and deflection.

  Further, as a technique related to weight reduction of a vehicle seat cushion, Patent Document 1 shows a frame shape of a seat frame, a cross section of the seat frame has a mountain shape, and one side of the mountain shape on a frame shape inner peripheral side of the seat frame. A concave curved surface is formed by covering the seat frame with an elastic net and pulling its peripheral edge from above the chevron of the seat frame and fixing it to the other side of the chevron. A technique is disclosed in which the seating surface is stretched so as to form a seating surface, and an angle is provided between the net and the inclined surface of the seat frame.

  As another technique related to weight reduction, Patent Document 2 discloses a base plate detachably attached to a seat frame, a block disposed on the base plate, a spring plate disposed on the block, and the spring plate. And the block is disposed so as to form a predetermined space between the base plate and the spring plate, and the spring plate is PP (elastic foam). Polypropylene) beads foam, PE (polyethylene) beads foam, PP foam, PE foam, AS resin (acrylonitrile / styrene resin) foam, EVA (ethylene vinyl acetate copolymer resin) and urethane foam material The spring seat is molded from the foam that is formed , Technical relates to a vehicle seat deflected into said space is disclosed when a force to said base plate direction was added.

  Next, when a cushion body is incorporated for a bed mattress, the bed mattress generally uses urethane foam as a cushioning material. As a technique relating to the weight reduction technology of the bed mattress, Patent Document 3 discloses that the support is rectangular. The surface is provided with a plurality of grooves that reach both ends in the short side direction, the grooves have a depth of 30 to 70 mm, a width of 15 to 80 mm, and a core material of 10 to 40 mm in thickness. , Made of a rectangular urethane foam having a hardness of 100 to 300 N, the short side is folded in two in the long side direction, both ends of the long side are fitted and supported in one concave groove of the support, and the frame is A technique provided to surround the periphery of the support is disclosed.

JP 2002-28044 A Japanese Patent No. 4009490 JP 2009-279086 A

In conventional general vehicle seat cushions, urethane foam is used as a cushioning material, and the cushioning properties are extremely high and the comfort is excellent. However, the urethane foam has a problem that it is inferior in recycling performance. Furthermore, in addition to being required to have optimal cushioning regardless of the weight of the occupant's weight, the vehicle seat cushions can cause the occupant's body to feel uncomfortable with the vertical acceleration applied to the occupant as the vehicle moves. No cushioning is required. On the other hand, to reduce fatigue when riding for a long time, it is necessary to support the occupant's body in the correct position and posture. For this reason, the function cannot be satisfied with only a very soft urethane foam, and the density of the urethane foam needs to be a certain level or more in order to secure a certain degree of rigidity. It was.

In the technique described in Patent Document 1, the net material that supports the pressure applied by the occupant is drawn into the seat frame installed around the seat cushion and is firmly fixed, and the pressure applied by the occupant's seating is finally transmitted through the net material. It was supported by the rigidity of the seat frame. Therefore, the structure of the seat frame must maintain a certain level of strength. For this reason, although the weight of the net material itself corresponding to the conventional cushion material is light, the weight of the seat frame tends to increase and the overall weight There was a problem that the reduction effect was not sufficient.

Furthermore, the cushioning property of the net material is limited because it is obtained mainly by the elongation of the material, and there is a tendency that sagging occurs due to long-term use and the merchantability is inferior. In addition, since the flat net material is stretched around the seat frame, the basic seat cushion shape is flat, and the three-dimensional shape necessary to support the occupant's body in an optimal position is obtained. As a result, there is a problem that the passengers feel uncomfortable. This is because an unstable hammock-like net material cannot stably support the occupant's body when a lateral G is applied to the occupant by the movement of the automobile.

Next, as for the technique of Patent Document 2, the spring plate is a plate-like foam having a substantially rectangular outer shape, and a plurality of grooves are formed in the lateral direction on the side of the spring plate on which an occupant sits. However, if the groove is shallow, flexibility cannot be given, and if the groove is deep, when the cushion material bends, excessive tensile force concentrates on the connecting part of the remaining groove bottom, causing large elongation deformation. There was a high risk of permanent deformation that could not be restored or fracture. If even a part of the connecting portion at the groove bottom is broken, the support is lost at once, the apparent hardness of the entire cushioning material is drastically lowered, and the function as the cushioning material is greatly impaired. Therefore, it is practically difficult to design the deflection of the cushion material to a certain level or more in order to avoid breakage, and it is difficult to provide a sufficient fit and comfort when seated.

Moreover, although the technique of patent document 2 has described that it can obtain a favorable seating feeling personally by selecting suitably the block from which height differs according to a passenger | crew's physique, There was a problem that in reality it had to be difficult to implement, because it had to be changed to a block of height suitable for me before sitting down by light weight.

Next, although the technology of Patent Document 3 is lighter than a conventional mattress using a metal spring, it uses urethane foam for the support and core, so it is inferior in recycling performance and lighter in weight. There was a problem that there was a limit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cushion body that is rich in cushioning and fitting properties when sitting or lying on a person, and is lightweight and excellent in recyclability.

In the present invention, the synthetic resin foam is flexible and capable of bending deformation and is excellent in resilience. The method described in JIS K7221-2: 2006 (23 ° C. ± 2 ° C., relative humidity 50 ± 350mm long with skin removed in 5% atmosphere
A test piece having a width of 100 mm and a thickness of 25 mm is pressed until the maximum deflection is 90 mm at a fulcrum distance of 300 mm and a test speed of 20 ± 1 mm / min, and a press deflection curve is recorded. ) Refers to a synthetic resin foam molded article having a bending deflection of 20 mm or more measured according to) and a pressing force of 2 to 100 N at the time of 20 mm deflection. Specifically, it refers to foamed polypropylene, foamed polyethylene, other polyolefin resin foams, modified polystyrene resin foams, and the like. The synthetic resin foam includes a bead foam molded body, and examples of the bead foam molded body include a polypropylene-based bead foam molded body and a polyethylene-based bead foam.

In the specific selection of the material, both ends of a bar-like or plate-like test piece having a length of about 400 mm are supported, the center is pushed back and forth by 25 mm and held for 30 minutes, and then the pressure is released, and then recovery from the deformation of the sample occurs. 90% or more is desirable. Alternatively, in accordance with a test performed with a conventional urethane foam cushion, the center portion of the sample supporting both ends is repeatedly pressed down and deformed a predetermined number of times, and the residual strain (also referred to as residual displacement) measured thereafter is determined. It is desirable to be below the fixed amount.

Such materials satisfying, for example, the density of the foamed polypropylene ^{0.06g / cm 3 ~0.015g / cm 3} , more preferably a density 0.035g ^/ cm ³ ~0.015g ^/ cm 3 or polyethylene foam, such as density 0.08g ^/ cm ³ ~0.03g ^/ cm 3 are preferred. On the other hand, rigid foamed urethane, polystyrene foam and the like which are poor in flexibility and can be easily broken by bending deformation are not preferable.

The inventors have studied materials in order to reduce the weight. As an example of a material that can be changed to urethane foam that has an open cell structure, synthetic resin foam that has a closed cell structure is generally lighter, more rigid, and more recyclable than urethane foam that has been commonly used as a cushioning material. Although it had the advantage of being easy, etc., when using bending and restoring force in the compression direction as a cushion, the reaction force tends to increase rapidly with the deformation of the foam due to the repulsive force of the air included It was inferior in comfort because it felt stiff and lacked cushioning.

In general, when a synthetic resin foam having a closed cell structure is used as a cushioning material by being bent in the compression direction like a urethane foam, it gradually loses its recovery force and generates creep as it is used for a long period of time. This is largely due to fatigue due to repeated deformation of the resin film constituting the bubbles and a drop in the pressure of the air contained therein. Therefore, it was not preferable as a material for a cushion used for a long time.

Therefore, the inventors analyzed the physical properties of the synthetic resin foam from various angles, so that it is not a structure that has been bent in the compression direction that has been used as a conventional general cushioning material, but can be bent and deformed. The present inventors have found that a method of utilizing the bending deformation and recoverability of a support made of a synthetic resin foam excellent in the above as a cushioning material is optimal.

In order to solve the problem described in “Problems to be Solved by the Invention”, the cushion body 1 according to claim 1 has a bending deflection amount of 20 mm or more measured according to the method described in JIS K7221-2: 2006. Further, a plurality of rod-like bodies 10 that are made of a synthetic resin foam having a pressure of 2 to 100 N when bent by 20 mm and are bent and deformed under the load of a seated person or a supine person, or a support body 2 having a single or plural plate-like shape 11 And a deformable region 5 formed so that the support 2 can be bent and deformed, and both ends in the longitudinal direction N of the support 2 on the support point side when the support 2 is bent and deformed 15 is characterized in that a bending deformation portion 4 that is bent by a load applied to the support 2 is formed.

The cushion body according to claim 2 is the cushion body according to claim 1, wherein the bending deformation portion 4 is formed at a central portion 16 in the longitudinal direction of the support body 2. .

  A cushion body 1 according to a third aspect is the cushion body 1 according to the first or second aspect, wherein the bending deformation portion 4 has a meandering shape 6 that expands and contracts in a spring shape by a load, or the front surface e and the rear surface f of the support body 2. It is characterized in that a notch 7 in the short direction T of the support 2 is formed which is bent by a load.

  A cushion body 1 according to a fourth aspect of the present invention is the cushion body 1 according to any one of the first to third aspects, wherein the deformation allowable region 5 is a space region, and the space region is filled with an elastic body 17. Alternatively, the elastic body 17 is arranged in a part of the space region.

The invention of the cushion body 1 described in claim 1 can replace the urethane foam that has been conventionally used in general with a synthetic resin foam, so that weight reduction and improvement in recyclability can be achieved. It is possible. Despite the use of synthetic resin foam, which is relatively hard and inferior to cushioning, fit, and creep resistance, it is possible to give high cushioning and fit, and freedom of design High degree of merchandise that can properly support the body of a seated person or a supine person and obtain high comfort, and exhibits excellent creep resistance equivalent to conventional urethane foam even when used for a long time. It has the effect of having.

When a load 9 is applied to the center portion 16 and the periphery of the support 2 by a seated person or a supine person, both end portions 15 of the support 2 bend before the center portion 16 and the periphery thereof, and thereafter the center portion. Since the 16 side is bent and deformed, there is an effect that the support 2 is bent widely and the cushioning property of the support 2 is enhanced.

The cushion body 1 according to the second aspect has the same effect as the first aspect, and when the load 9 is applied to the central portion 16 of the support body 2 and the periphery thereof by the seated person or the supine person, Since the central portion 16 is bent before both end portions 15 and then the both end portions 15 are bent and deformed, the contact area of the seated person or the supine person is submerged first, and the cushioning property of the support 2 is improved. Play.

  The cushion body 1 according to the third aspect has the same effect as that of the first or second aspect, and in the case of the meandering shape 6, the portion meandering like a spring expands and contracts like a spring, and thereafter the central portion 16 As a result of bending deformation, the cushioning property is improved, and the amount of bending of the support 2 can be adjusted by the number of bent portions corresponding to the spring-like peak portions. And in the case of the form which provides the notch 7, there exists an effect of improving cushioning property because the notch 7 part bends first and the center part 16 bends and deform | transforms after that.

  The cushion body 1 according to claim 4 has the same effect as any one of the inventions according to any one of claims 1 to 3, and further, a support body by a load of a seated person or a supine person in a bending deformation region of the support body 2. By disposing the elastic body 17 exhibiting a damping property against the impact during the bending deformation of 2, the bending deformation generated in the support body 2 can be attenuated, and the cushioning property can be enhanced. Further, durability against an impact caused by, for example, jumping of a child or collision of a heavy object with respect to the support 2 can be improved.

It is explanatory drawing of a cushion body provided with a some rod-shaped support body and a leg. It is explanatory drawing of a cushion body provided with a some plate-shaped support body and a leg body. It is a front view of the arrow A in FIG. 1, (a) is a state at the time of no load, (b) is a figure of the state on which the load by the load was applied. It is explanatory drawing of the support body which has the meandering form at both ends. It is a support body having a meandering shape, (a) is a state when no load is applied, (b) is a state immediately after a load is applied, and (c) is a diagram showing a state when a load is applied. It is explanatory drawing of the support body which has the meandering form in the both ends and the center part. It is a support having a meandering shape at both ends and in the center, where (a) shows a state when no load is applied, (b) shows a state immediately after the load is applied, and (c) shows a state when the load is applied. FIG. It is a figure of the support body which provided the notch in both ends, (a) is a state at the time of no load, (b) is in the state just after load loading, and (c) is a figure showing the state at the time of load load progressing. . It is an enlarged view of the notch part of the support body which provided the notch, (a) is a form in which the notch on the front side is arranged outward from the notch on the back side, and (b) is the notch on the front side. (C) is a form in which the notch on the front surface side and the notch on the back surface side are disposed at the same position in the longitudinal direction of the support body. FIG. FIG. 7 is a diagram in which an elastic body is filled in the deformation-permitted region, (a) is a diagram in which the cushion body of FIG. 4 is filled, and (b) is the cushion of FIG. It is the figure arrange | positioned so that a body might be filled.

Hereinafter, embodiments of the cushion body 1 according to the present invention will be described.

The cushion body 1 according to the present invention is used when a person is seated or lying on the back, such as a vehicle, a ship, a seat for a vehicle such as an airplane, a sofa, a chair, a cushion, a bed, a sleeper, a mattress, a mattress, a pillow, a mat, and the like. Moreover, it can be set as the component as a cushion.

The cushion body 1 according to the present invention comprises a synthetic resin foam having a bending deflection amount measured according to the method described in JIS K7221-2: 2006 and a bending deflection amount of 20 mm or more, and a pressure at the time of 20 mm deflection of 2 to 100 N. A plurality of rod-like bodies 10 that are bent and deformed in response to the load 9 of the supine, or one or a plurality of plate-like support bodies 2, and a deformation-allowable region 5 that is formed so that the support bodies 2 can be bent and deformed. At both ends 15 in the longitudinal direction N of the support 2 that is the support point side during bending deformation, or both ends 15 and the central portion 16 in the longitudinal direction N of the support 2. Further, a bending deformation portion 4 that is bent by a load 9 applied to the support 2 is formed.

  Since the cushion body 1 of the present invention uses the synthetic resin foam which is the material of the support body 2 of the present invention, the structure of the support body 2 and the leg body 3 is formed in a substantially portal shape as shown in FIG. The cushion body according to the present invention is obtained by bending and deforming the support body 2 made of a synthetic resin foam to the deformation allowable region 5 side by a load at the time of sitting or lying on a person. 1 can make a seated person or a supine person feel high sitting comfort and high sleeping comfort.

  The cushion body 1 of the present invention includes a plurality of rod-like bodies 10 as shown in FIG. 1 or a plurality or a single plate-like support body 2 as shown in FIG. The support 2 corresponds to a seat for a vehicle, a ship, an airplane or the like, a sofa or a chair, a seat back, a seat cushion, a bed, a sleeper, a mattress, or a mattress body. Corresponds to the surface on which lies, corresponds to the surface against which the head of the pillow abuts, and corresponds to the upper surface of the mat.

The deformation allowable region 5 may be a space region, or may be a form in which an elastic body 17 is disposed in at least a part of the space region, or as shown in FIG. The form arrange | positioned so that all the elastic bodies 17 may be filled may be sufficient.

Next, the support body 2 will be described. The support 2 is made of a synthetic resin foam, and is a load 9 caused by human seating or supine, and when no load is applied, the load 9 is loaded from the state shown in FIG. As shown in FIG. 4, the material is bent and deformed toward the deformation allowable region 5 side. As shown in FIG. 1 or FIG. 2, gaps 12 are provided between the supports 2 in the case of a plurality of rod-like shapes 10 and a plurality of plate-like shapes 11.

  Next, the support 2 is provided with bending deformation portions 4 at both end portions 15 in the longitudinal direction N, or at both end portions 15 and the central portion 16 in the longitudinal direction N. The bending deformation portions 4 are shown in FIGS. As shown in FIG. 7, the shape of the meandering 6 which expands and contracts in a spring shape by a load is applied, or as shown in FIG. 8 or 9, the front surface e and the back surface f of the support 2 are bent by a load or no load. The cutout 7 in the short direction T of the support 2 is formed.

  First, regarding the setting of the form of the meandering 6, the thickness of the support 2 at the bent portion, the bending angle of the bent portion, and the number of the bent portions are set according to the hardness of the support 2 and the target load 9.

  As shown in FIG. 4, the form in which the meandering-shaped bending deformed portion 4 is formed at both end portions 15 is the same as that shown in FIG. From the loaded state, as shown in FIG. 5 (b), first, the bent portions of both end portions 15 of the support 2 are bent before the central portion 16, and then the central portion 16 is bent as shown in FIG. 5 (c). By bending and deforming, a seated person or a supine person can feel a high cushioning property.

  Next, as shown in FIG. 6, the form in which the meandering-shaped bending deformation portion 4 is formed at both end portions 15 and the central portion 16 is shown in FIG. From the unloaded state shown in FIG. 7 (a), as shown in FIG. 7 (b), the bent portion of the central portion 16 of the support 2 is first bent before both end portions 15, and then in FIG. 7 (c). As shown, the both ends 15 are bent and deformed, so that a seated person or a supine person can feel a high cushioning property.

  Next, in the form in which the notch 7 is provided, the size and the cross-sectional shape of the notch 7 and the position at which the notch 7 is provided are supported by the notch 7 according to the hardness of the support 2 and the target load 9. 2 is set so that it is easy to bend. 9 (a), the notch 7 on the front surface e side is disposed closer to the center side 16 than the notch 7 on the back surface f side, as shown in FIG. 9 (a). The notch 7 on the front surface e side is arranged outwardly from the notch 7 on the back surface f side, or the notch 7 on the front surface e side is notched on the back surface f side as shown in FIG. There is a form in which it is arranged at the same position in the longitudinal direction T as the notch 7. As for the shape and size of the notch 7, the shape of the notch 7 and the number of the notches 7 are set so that the support 2 is not damaged even at the maximum load 9 applied during use.

    In the form in which the notch 7 is provided, when a load 9 of a seated person or a supine person is loaded on the support body 2, as shown in FIG. 8 (b), from the unloaded state shown in FIG. The notch 7 at both ends 15 in the longitudinal direction N of the support 2 bends ahead of the central portion 16 and then the central portion 16 is bent and deformed as shown in FIG. High cushioning can be felt.

Next, as shown in FIG. 10, the elastic body 17 is disposed so as to fill the deformation allowable region 5 on the side protruding by the bending deformation of the support body 2, and the support body 2 receives the load and bends and deforms. Then, the elastic body 17 is pressed and contracted.

When the elastic body 17 is pressed and contracted, bending deformation generated in the support body 2 can be attenuated, and cushioning properties can be improved. Further, durability against an impact caused by, for example, jumping of a child or collision of a heavy object with respect to the support 2 can be improved.

Examples of the elastic body 17 include urethane foam, foamed resin molded body, foamed resin particles, foamed rubber, elastomer, fibrous material, three-dimensional knitted fabric, wool, silk, cotton, fiber joints such as three-dimensional spring structures, gas It is made of a material that has resilience to repeated loads, such as a stretchable bag-like body or a spherical body that is sealed, and has a damping property such as fiber or rubber. The pressure plate of a flat disk with a diameter of 200 mm specified in JIS K6400-2: 2012 concerning the method of obtaining the above is a hardness of 20 to 600 N at 25% compression (D method). If it is less than 20N, it is too soft and the reaction force to return to its original form after being compressed is too weak to have damping. If it exceeds 600N, it is too hard when a load is applied and it is compressed and deformed. Does not have attenuating property.

In addition, the elastic body 17 is disposed on the protruding side of the support body 2 due to the bending deformation, and attenuates the bending deformation generated in the support body 2 to enhance the cushioning property. Then, a metal plate spring, a metal linear spring, an S spring, a coil spring, rubber, an elastic resin body, a synthetic fiber such as polyester, or the like is contacted with or separated from the protruding side of the support 2 by bending deformation. You may arrange | position the thing which has elasticity, such as what was spun at high density. Moreover, you may affix a nonwoven fabric etc. to the both ends or the whole surface to the surface of the side which expands-contracts at the time of the support body 2 bending.

Next, the synthetic resin foam will be described. The synthetic resin foam in the present invention is flexible, can be bent and deformed, and has excellent restorability. The method described in JIS K7221-2: 2006 (23 ° C. ± 2 ° C., relative humidity 50 ± 5% A test piece having a length of 350 mm, a width of 100 mm, and a thickness of 25 mm, with the skin removed, is loaded up to a maximum of 90 mm at a distance between fulcrums of 6 and a test speed of 20 ± 1 mm / min, and a load deflection curve is recorded. ) Refers to a synthetic resin foam molded article having a bending deflection of 20 mm or more and a load of 2 to 100 N when bent by 20 mm. A synthetic resin foam molded article that causes fracture when the bending deflection is less than 20 mm is not suitable from the viewpoint of durability. When the cross section of the support body 2 required to support the pressing by the body becomes very large and the load at the time of 20 mm bending is less than 2N or more than 100N, it is difficult to generate a preferable amount of bending by the load applied by the occupant. Both of them are difficult to design. Specifically, it refers to foamed polypropylene, foamed polyethylene, other polyolefin resin foams, modified polystyrene resin foams, and the like. Among the foams, an in-mold molded body of resin foam particles is preferable from the viewpoint of shape flexibility (designability) considering a fit.

The polyolefin resin constituting the expanded particles used in the present invention is a polyolefin resin having an olefin component unit as a main component, specifically, a polypropylene resin, a polyethylene resin, and a mixture of two or more thereof. Is mentioned. The above-mentioned “main component” means that the olefin component unit is contained in the polyolefin resin in an amount of 50% by weight or more, and the content thereof is preferably 75% by weight or more, more preferably 85% by weight. % Or more, more preferably 90% by weight or more.

Examples of the polypropylene-based resin include resins having a propylene component unit of 50% by weight or more, and examples thereof include a propylene homopolymer or a copolymer with another olefin copolymerizable with propylene. Examples of other olefins copolymerizable with propylene include ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1 Examples thereof include α-olefins having 4 to 10 carbon atoms such as heptene and 3-methyl-1-hexene. The copolymer may be a random copolymer or a block copolymer, and may be not only a binary copolymer but also a ternary copolymer. The other olefin copolymerizable with propylene in the copolymer is preferably contained in a proportion of 25% by weight or less, particularly 15% by weight or less, and the lower limit is 0.3% by weight. Preferably there is. These polypropylene resins can be used alone or in combination of two or more. Polypropylene resin has a tensile elastic modulus (E) specified in JIS K7161: 1994 (test piece: JIS K 7162 (1994), test piece 1A type (direct molding by injection molding), test speed: 1 mm / min)). A resin foam obtained by foaming a base resin having a value of 600 MPa or more is preferable.

Examples of the polyethylene resin include resins having an ethylene component unit of 50% by weight or more, such as high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer. A copolymer, an ethylene-propylene-butene 1 copolymer, an ethylene-butene 1 copolymer, an ethylene-hexene 1 copolymer, an ethylene-4 methylpentene 1 copolymer, an ethylene-octene 1 copolymer, and the like. The mixture of 2 or more types is mentioned.

And in concrete selection of the synthetic resin foam, both ends of a rod-shaped test piece having a length of about 400 mm are supported, the center is pushed back and forth by 25 mm and held for 30 minutes, and then the pressure is released and then the sample is deformed. Residual strain measured after the center portion of the sample that supported both ends was repeatedly pressed down and deformed in accordance with tests performed on materials with 90% or more recovery or conventional urethane foam seat cushions. A material in which is less than a predetermined amount is desirable. The predetermined number or the predetermined amount conforms to a specification arbitrarily determined by each manufacturer when selecting a conventional material.

Such materials satisfying, for example, the density of the foamed polypropylene ^{0.06g / cm 3 ~0.015g / cm 3} , more preferably a density ^{0.035g / cm 3 ~0.015g / cm 3} , or of foamed polyethylene such as density 0.08g ^/ cm ³ ~0.03g ^/ cm 3 are preferred. Such a material is obtained by the method described in JIS K7221-2: 2006 (a test piece having a length of 350 mm, a width of 100 mm, and a thickness of 25 mm with the skin removed in an atmosphere of 23 ° C. ± 2 ° C. and a relative humidity of 50 ± 5%. In a test conducted in accordance with a distance of 300 mm at the fulcrum 6 and a load of up to 90 mm at a test speed of 20 ± 1 mm / min and recording a load deflection curve), the load when the bending deflection is 20 mm is 2 to 100 N and The flexible urethane foam, which is generally used for flexibility and flexural rigidity, on the other hand, has a load of 0.46 N when the bending deflection is 20 mm, and the bending rigidity is greatly inferior. It is not suitable as a material constituting 1.

  Below, the creep property and bending rigidity at the time of using a synthetic resin foam are demonstrated. First, in order to evaluate the creep property, compression set according to JIS K 6767: 1999 was measured. A test piece having a length of 50 mm, a width of 50 mm, and a thickness of 25 mm is compressed into a 25% distorted state and left at a temperature of 23 ° C. ± 2 ° C. for 22 hours. The thickness is measured 24 hours after the end of compression. The compression set was determined by compression set (%) = (test piece original thickness (mm) −thickness 24 mm after completion of compression (mm)) ÷ test piece original thickness (mm) × 100.

As a result of the test, the compression set of the 45-fold polypropylene foam particle molded body was 11%. On the other hand, the compression set of the polyurethane foam by the same measuring method is 2% or less. This is because conventional urethane foam, which is generally used as a cushioning material for seat cushions, exhibits cushioning properties by compression deformation. If it is simply replaced with a synthetic resin foam, compression set is generated, and the original cushion It is shown that it is difficult to maintain the product and the commercial value is lowered.

DESCRIPTION OF SYMBOLS 1 Cushion body 2 Support body 3 Leg body 4 Bending deformation part 5 Deformation allowable region 6 Meandering shape 7 Notch 9 Load 10 Rod shape 11 Plate shape 12 Gap 15 End portion 16 Central portion 17 Elastic body N Longitudinal direction T Short direction e Surface f Back side

Claims (4)

Bending under the load of a seated person or a supine person consisting of a synthetic resin foam having a bending deflection amount measured in accordance with the method described in JIS K7221-2: 2006 of 20 mm or more and a pressure at the time of 20 mm deflection of 2 to 100 N A plurality of deformed rod-shaped or single or plural plate-shaped supports;
A deformable region formed so that the support can be bent and deformed,
A cushion body, wherein a bending deformation portion that is bent by a load applied to the support body is formed at both ends in the longitudinal direction of the support body on the support point side during bending deformation of the support body.   The cushion body according to claim 1, wherein the bending deformation portion is formed at a central portion in the longitudinal direction of the support body.   The bending deformation part is a meandering form that expands and contracts in a spring shape by a load, or a form in which notches in the short direction of the support body that are bent by a load are formed on the front and back surfaces of the support body. The cushion body according to claim 1 or 2, characterized by the above.   The deformation-permissible region has a form composed of a space region, a form arranged to fill the space region with an elastic body, or a form in which an elastic body is arranged in a part of the space region. The cushion body according to any one of claims 1 to 3.

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