JP2015092949A - Double layer cushion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cushion body of a two-layer structure which is rich in cushioning property while a person is seated or lying supine, is capable of achieving weight saving, and is excellent in recyclability.SOLUTION: A cushion body of a two-layer structure includes a first cushion body composed of a support body made of synthetic resin foam whose deflection in bending measured according to a method described in JIS K7221-2:2006 is 20 mm or more, and whose load at the time of 20 mm deflection is 2-100 N and a leg body for supporting the support body, in which the support body and the leg body form a space part in which the support body can be bent and deformed, and which receives a load from a seated or lying person, and a second cushion body having elasticity of a 25% compressive hardness of 5-200 N/φ100 mm installed on the seated or lying person side of the support body which covers at least the surface range on the seated or lying person side of the support body, and receives a load from the seated or lying person.

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 two-layer cushion body.

  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 load such as a wire stretched around a frame or a flat support, 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 load 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. A seating portion having a skin 7 covering the surface, wherein the block is disposed so as to form a predetermined space between the base plate and the spring plate, and the spring plate is a foam having elasticity. One of (polypropylene) bead foam, PE (polyethylene) bead foam, PP foam, PE foam, AS resin (acrylonitrile / styrene resin) foam, EVA (ethylene vinyl acetate copolymer resin) and urethane foam material Formed with a foam formed of It is a technique related to a vehicle seat flexes the 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 is still frequently used because of its extremely high cushioning properties and excellent comfort. 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 technology described in Patent Document 1, the net material that supports the load by the occupant is drawn into the seat frame installed around the seat cushion and firmly fixed, and the load 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.

  Accordingly, an object of the present invention is to provide a two-layered cushion body that is excellent 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 load is applied to a test piece having a width of 100 mm and a thickness of 25 mm at a distance of 300 mm between the fulcrums 6 at a test speed of 20 ± 1 mm / min until the maximum deflection is 90 mm, 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. 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-shaped or flat plate-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 load is released to recover from the deformation of the sample. 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 two-layer structure cushion body 1 according to claim 1 is an amount of bending deflection measured according to the method described in JIS K7221-2: 2006. Is composed of a support 2a made of a synthetic resin foam having a load of 2 to 100 N when bent by 20 mm and a leg 2b that supports the support 2a, and the support 2a and the leg 2b. The support body 2a forms a space part 4 that can be bent and deformed, receives the load 9 from the seated person or the supine person, and has an elasticity of 5 to 200 N / φ100 mm in hardness at 25% compression. And is installed on the seated person or supine side of the support 2a, covers at least the surface area of the support 2a on the seated person or supine side, and receives a load 9 from the seated person or the supine person Cushion And a body 3.

  The two-layer structure cushion body 1 according to claim 2 is characterized in that, in claim 1, the second cushion body 3 is made of a breathable structure or a breathable material.

  The two-layer structure cushion body 1 according to claim 3 is the first cushion according to claim 1 or 2, wherein the first cushion body 2 and the second cushion body 3 create a state in which stagnant air flows. Means for blowing warm air, cold air or dehumidified air into the body 2 and the second cushion body 3, and means for inserting a sheet-like heating element on the front or back side of the second cushion body 3. At least one of these means is provided.

  The two-layer structure cushion body 1 of Claim 1 can replace the support body 2a of the 1st cushion body 2 with the synthetic resin foam for the urethane foam generally used conventionally. Therefore, weight reduction and recyclability can be improved. 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.

  Moreover, since the support body 2a of the first cushion body 2 is supported by the leg body 2b and forms a space part 4 that can be bent and deformed, the seated person or the supine person abuts on the load 9 received from the seated person or the supine person. The entire support 2a can be easily bent and bent within the elastic range. Accordingly, the body can be sunk into the two-layer structure cushion body 1 without feeling a sense of impact when the seated person or the supine person is in contact with the support body 2a.

  Furthermore, when the seated person or the supine person presses the finger, for example, the second cushion body 3 is elastically deformed while maintaining a close contact with the finger in a region that is substantially the same as the local range that receives the load 9 due to the pressing. Therefore, when the seated person sits down or when the supine person lies down, the two-layer structure cushion body 1 without causing a gap while maintaining close contact with the body along the outer shape of the body of the seated person or supine person The sinker can give the seated person and the supine person a feeling of supporting the body.

  Therefore, by combining the first cushion body 2 and the second cushion body 3, the two-layer structure cushion body 1 according to claim 1 can provide extremely high cushioning properties and fit properties.

  The two-layer structure cushion body 1 according to the second aspect has the same effects as the first aspect. Further, since the second cushion body 3 is made of a breathable structure or a breathable material, the air in the two-layer structure cushion body 1 does not flow and stay, so that a seated person or a supine person has two layers. Even if the structure cushion body 1 and the body are in close contact with each other, there is an effect that it is difficult to feel stuffiness.

  The two-layer structure cushion body 1 according to the third aspect has the same effects as the first or second aspect. Further, means 30 for creating a state in which the accumulated air inside the first cushion body 2 and the second cushion body 3 flows, means 30 for blowing warm air, cold air or dehumidified air into the interior, and the second cushion body 3 Since at least one means 30 of the means 30 for inserting the sheet-like heating element is provided on the front surface side or the back surface side, the two-layer structure cushion body 1 and the body are in close contact with each other. Even if it does not feel stuffy, it has the effect of being able to feel a refreshing sensation of heat and a feeling of warmth even with changes in ambient temperature and humidity.

It is the front schematic diagram which removed the skin of the front side which shows an example of the embodiment of the two-layer structure cushion object concerning the present invention. It is a side surface schematic diagram of the cross section AA in FIG. It is the front schematic diagram which remove | eliminated the skin of the front side which shows the state which the load from the seated person acted on the two-layer structure cushion body shown in FIG. It is the front schematic diagram which remove | eliminated the skin of the front side of the two-layer structure cushion body provided with the 2nd cushion body comprised with the plate-shaped body which consists of one layer. It is the front schematic diagram which removed the outer skin of the front side of the two-layer structure cushion body provided with the 2nd cushion body comprised with the plate-shaped body which consists of two layers. It is the front schematic diagram which remove | eliminated the skin of the front side of the two-layer structure cushion body provided with the 2nd cushion body comprised with the some rod-shaped body which has a substantially annular shape. It is the front schematic diagram which removed the skin of the front side of the double layer structure cushion object which provided the groove | channel or the notch in the surface side. It is the front schematic diagram which removed the skin of the front side of the two-layer structure cushion body which provided the groove | channel or the notch in the 1st cushion body side. It is a general | schematic perspective view of the net-like foamed resin net | network which is a 2nd cushion body. It is a schematic explanatory drawing which provided the means to flow air in a space part. It is a schematic diagram of a load durability test. It is a schematic diagram of a back pressure jig, (a) is a top view, (b) is a front view, and (c) is a side view. It is a residual displacement amount diagram by repeated load. It is a load-displacement amount diagram in a seat back shape. It is a comparison figure of the bending test by JISK7221-2 with a foam and a non-foam.

  Hereinafter, an embodiment of a two-layer structure cushion body 1 according to the present invention will be described.

  The two-layer structure cushion body 1 according to the present invention is made 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 load at the time of 20 mm deflection of 2 to 100 N. The support body 2a and the leg body 2b that supports the support body 2a, and the support body 2a and the leg body 2b form a space portion 4 in which the support body 2a can be bent and deformed. The first cushion body 2 that receives the load 9 from the person, and the elasticity of 5 to 200 N / φ100 mm in hardness at the time of 25% compression, installed on the seated person or supine side of the support body 2a, and the support A second cushion body 3 that covers at least the surface area of the body 2a on the side of the seated person or the supine person and receives a load 9 from the seated person or the supine person.

  The two-layer structure cushion body 1 includes a first cushion body 2 and a second cushion body 3, and when the seated person sits down or when the supine person lies down, the body of the seated person or the supine person first becomes the second cushion body. 3, the range of the second cushion body 3 on which the seated person or the supine person comes into contact is elastically deformed by the load 9 from the seated person or the supine person, and the second cushion body 3 is elastically deformed, The first cushion body 2 in contact with the second cushion body 3 is bent and deformed by the load 9 over the entire first cushion body 2 and is bent.

  Therefore, the two-layered cushion body 1 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, and a mat. For example, it can be a component as a cushion.

  The first cushion body 2 includes a support body 2a and a leg body 2b that supports the support body 2a, and the support body 2a and the leg body 2b form a space portion 4 in which the support body 2a can be bent and deformed. To do.

  The support body 2a and the leg body 2b forming the first cushion body 2 may be separated or integrally formed. The form of the first cushion body 2 is not limited to the portal shape as shown in FIG. 1, and the first cushion body 2 may be any form that can be bent and deformed by receiving a load 9 from a seated person or a supine person.

  The support body 2a of the first cushion body 2 is not easily bent or bent with respect to the load 9 applied to the local range of the finger level from the body of the seated person or the supine person. Alternatively, as shown in FIG. 3, the load 9 over a wide range of the whole body level is not limited to the range of the load 9, but bends and bends as a whole. .

  Next, the second cushion body 3 has elasticity with a hardness of 5 to 200 N / φ100 mm at 25% compression, and is installed on the seated person or supine side that is the surface side of the support body 2a. The second cushion body 3 covers at least the surface area of the supporter 2a on the side of the seated person or the supine person, and receives the load 9 from the body of the seated person or the supine person before the first cushion body 2.

  Further, as shown in FIG. 3, the second cushion body 3 is compressed in a range substantially the same as the range in which the load 9 is applied to the load 9 applied to any range from the local range to a no-load. Then, it will be elastically deformed to restore its original shape.

  The second cushion body 3 forms a surface that comes into contact with the body of a seated person or a supine person and receives a load 9 from the body, and is made of a structure or material having cushioning properties and air permeability.

  As a structure which has the cushioning property of the 2nd cushion body 3, the structure which adheres or covers trims, such as cloth, leather, or synthetic leather, on the surface of the 2nd cushion body 3, the 2nd cushion body 3 and the 1st cushion body 2 And / or a configuration in which a material with elasticity that does not impair or further improve the flexibility of the second cushion body is disposed on the surface side of the second cushion body 3, and / or the second cushion body A configuration in which a sheet-like or net-like member for improving the setting / assembling workability and / or the sewing workability of the skin material is disposed between the body 3 and the first cushion body 2 may be used. As for the sheet-like or net-like one, a means for covering or adhering to the second cushion body 3 may be used.

  Examples of the air-permeable structure of the second cushion body 3 include a three-dimensional woven fabric, a net-like foamed resin net, an air cushion, or a laminate of non-woven cloth. Examples of the air-permeable material include urethane foam and foam. Rubber, plastic foam resin, cotton or animal hair. Any structure or material having air permeability may be used.

  As an example, the net-like foamed resin net 3c means a form in which a linear foam material is formed in a rhombus-like net shape as shown in FIG. 9, for example, a linear foam having a diameter of 2 to 5 mm is 7 It has a form in which nets made in a diamond-shaped net are laminated with an interval of 10 mm. Since the space having the rhombus shape is provided, the air permeability is extremely good and the cushioning property is also high.

  The form of the second cushion body 3 may be any form that forms a surface that contacts the body of the seated person or the supine person and receives the load 9 from the body, and has a substantially semicircular cross section as shown in FIG. FIG. 6 shows a configuration composed of a plurality of rod-shaped bodies 3a, a configuration composed of a single-layer plate as shown in FIG. 4, a configuration composed of a two-layer plate as shown in FIG. There are a form constituted by a plurality of rod-like bodies having a substantially annular shape as shown, a form provided with grooves or notches as shown in FIG. 7 or FIG. 8, and any form may be adopted.

  Therefore, when a seated person or a supine person sits or lies on the two-layer structure cushion body 1, first, the second cushion body 3 wraps around the body without generating a gap along the outer shape of the body of the seated person or the supine person. The first cushion body 2 is then supported while being elastically deformed in the compression direction, and the first cushion body 2 is then supported by the load 9 from the seated person or the supine person via the second cushion body 3. The whole 2a is easily bent and bent within the elastic range. Thereby, a seated person or a supine person can sink a body into the two-layered structure cushion body 1 without feeling a sense of impact when contacting the two-layered structure cushion body 1 while feeling cushioning and fit.

  Next, the means 30 for flowing air in the first cushion body 2 and the second cushion body 3 will be described. The means 30 for flowing air may be any means 30 for flowing air in the first cushion body 2 and the second cushion body 3, for example, means provided with a fan for sending or sucking air into the space portion 4, There are means for flowing air from an air conditioner through a duct, means for sending or sucking air from a fan installed in a place other than the two-layer structure cushion body 1 through the duct, and the like. Any means may be used as long as it is capable of feeding and sucking air.

  In addition, the means 30 for flowing air may be provided with means 30 capable of blowing hot air, cold air, or dehumidified air. Thus, when the temperature is low and the cold is felt, warm air can be blown into the first cushion body 2 and the second cushion body 3, and when the temperature is high and the heat is felt, the cold air is sent to the first cushion body 2 and The air can be blown into the second cushion body 3, and when it feels damp moisture, it can inhale humid air and send out the dehumidified air, and the seated person or the supine person can change the environment of temperature and humidity. Even if there is, you can feel a comfortable refreshing feeling and warmth.

  Furthermore, a thin sheet-like heating element (not shown) can be inserted on the front side of the second cushion body 3 which is the seated person or supine side or the back side which is not the seated person or supine side. A control device (not shown) for controlling the temperature of the sheet-like heating element is provided, and the seat-like heating element can give a comfortable thermal feeling to a seated person or a supine person. Since the synthetic resin foam which is the material of the first cushion body 2 disposed on the back surface side of the second cushion body 3 has a heat insulating effect, it is possible to prevent heat from escaping to the back surface of the two-layer structure cushion body 1. it can.

  As shown in FIG. 10, the air flow 31 from the ventilation means 30 passes through the space 2 between the support bodies 2a of the first cushion body 2 from the space 4 and is second if the ventilation means 30 is set in a blowing state. If the ventilation means 30 passes through the inside of the cushion body 3 and is sent to the outside, conversely, if the ventilation means 30 is set in the suction state, the support body 2a of the first cushion body 2 passes through the inside of the second cushion body 3 from the outside. It passes between and flows into the space part 4.

  Thereby, even if the seated person and the supine person are in close contact with the two-layer structure cushion body 1, the seated person or the supine person can comfortably sit or lie down without feeling stuffy due to the air flow 31.

  Next, a two-layer structure cushion body 1 according to an embodiment of the present invention is shown in FIGS. The two-layer structure cushion body 1 includes a first cushion body 2 and a second cushion body 3. And the outer skin 10 is coat | covered on the surface side which the seated person 11 of the 2nd cushion body 3 or a supine person contacts. Moreover, the 2nd cushion body 3 shown in FIG. 1 is comprised by the some rod-shaped body 3a which has a substantially semicircular cross section.

  When the occupant 11 sits on the two-layer structure cushion body 1, as shown in FIG. 3, the load 9 from the occupant 11 is applied to the second cushion body 3 and corresponds to the range in which the occupant 11 abuts. The central part of the second cushion body 3 to be elastically deformed in the compression direction. Since the seat 11 does not feel the reaction force from the second cushion body 3 due to the elastic deformation, the seat 11 receives the cushioning property, the fit and the feeling of being wrapped. On the other hand, in FIG. 3, since the seated person 11 has not contact | abutted, the both ends of the 2nd cushion body are not compressed.

  A load 9 is applied to the first cushion body 2 by elastic deformation of the second cushion body 3 in the compression direction. The first cushion body 2 located in the range where the load 9 is applied is bent and deformed within the elastic range over the entire area of the first cushion body 2 as shown in FIG. When the load 9 and the reaction force between the first cushion body 2 and the second cushion body 3 are balanced, the sinking of the seated person 11 stops.

  Thereafter, when the load 9 changes due to the movement of the seated person 11 or the like, the first cushion body 2 is bent and deformed within an elastic range so as to balance the generated load 9, and the second cushion body 3 is elastically deformed in the compression direction. Thereby, the seated person 11 can feel good sitting comfort while sitting.

  When the seated person 11 stands up, it will be in a no-load state, so that the first cushion body 2 and the second cushion body 3 are recovered to their original form.

  Next, the synthetic resin foam constituting the support 2a will be described. The synthetic resin foam is flexible, can be flexibly deformed, and has excellent resilience. The method described in JIS K7221-2: 2006 (in an atmosphere of 23 ° C. ± 2 ° C. and relative humidity of 50 ± 5%) The test piece having a length of 350 mm, width of 100 mm, and thickness of 25 mm with the skin removed in step 3 is loaded up to a maximum of 90 mm at a distance of 300 mm between the fulcrums 6 and a test speed of 20 ± 1 mm / min, and a load deflection curve is recorded. It refers to a synthetic resin foam molded article having a bending deflection of 20 mm or more and a load at the time of 20 mm deflection of 2 to 100 N. 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 2a required for supporting the load by the body becomes very large and the load at the time of 20 mm bending is more than 100N, it is difficult to generate a preferable bending amount, and it is difficult to design a preferable one. 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.

  Then, in the specific 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 load is released, and then the deformation from the sample is changed. 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 Flexural rigidity is excellent as well as flexibility, but on the other hand, a flexible urethane foam that has been generally used is not suitable as a material constituting the cushion body 1 of the present invention because the bending rigidity is greatly inferior at 0.46 N.

  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.

  Next, the sample plate 21 is placed at room temperature using a back-shaped pressurizing jig 20 (ellipse length 440 mm, depth (width) 290 mm, height 60 mm in front view) as shown in FIG. A load durability test was performed by measuring the residual displacement after applying a load of 490 N repeatedly 5,000 times, 10,000 times, and 15,000 times. In order to investigate the residual displacement when the synthetic resin foam is bent and deformed, as shown in FIG. 11, it is a flat polypropylene foam 45 times expanded product having a thickness of 20 mm and a width (depth) of 600 mm. The sample plate 21 was used as both-end support at an interval of 340 mm. The results of the load durability test are shown in FIG.

  From FIG. 13, the specification required for the conventional urethane foam is a residual displacement of 5 mm or less (line C in FIG. 13), whereas in the case of the synthetic resin foam of the present invention (line D in FIG. 13). Indicates that the residual displacement is 2.5 mm, which is within the range of the specification.

  Therefore, from FIG. 13, when the bending and deformation of a synthetic resin foam capable of bending deformation and excellent in resilience is used as a cushioning material, it is comparable to a conventionally used urethane foam, or It has been shown to have greater creep resistance.

  When the synthetic resin foam is used as the support 2a, the creep resistance is higher than that of the urethane foam. When the center part is pushed down and bending deformation occurs, each part of the member is pulled, compressed, sheared, etc. The member deforms, but the degree of each deformation is less than the amount of direct deformation in the case of using a cushion material by simply compressing the member as in the past, and the recovery range is not impaired. Because it stops at.

  Next, FIG. 14 shows a seat cushion type test body using a support 2a made of a synthetic resin foam supported at both ends, and a seat cushion type test body using a urethane foam having a conventional structure as shown in FIG. This is an example in which the reaction force generated when a load is applied at a compression speed of 100 mm / min with a simple back-shaped processing jig 20 is compared. The size of the test body using urethane foam is 650 mm wide, 350 mm long and 100 mm thick, and the test body using synthetic resin foam is a foamed polypropylene 45 foam product with a length of 350 mm, a width of 50 mm and a thickness of 30 mm. Are arranged in a plurality of rows at intervals of 2 mm. A thin line U shown in FIG. 14 is a load-displacement diagram of urethane foam prepared for comparison and generally used for a seat cushion, and a thick line P is a center of the support 2a made of the synthetic resin foam according to the present invention. It is a load-displacement amount diagram at the time of pushing and bending. Further, the load-displacement amount line when pressed down is indicated by u1 and p1, and the load-displacement amount line when released after being pressed is indicated by u2 and p2.

  FIG. 14 shows that the support 2a made of a relatively hard synthetic resin foam can obtain almost the same flexibility as a conventional urethane foam when it is structured to obtain cushioning properties by bending deformation. Yes.

  Next, FIG. 15 selects foamed polypropylene as an example of a synthetic resin foam, and a sample made of a non-foamed resin plate (thickness 1 mm) made of an equivalent resin and a sample made of a foamed polypropylene 45 times foamed product (thickness 45 mm). ) JIS K7221-2: 2006 (length of 350 mm, width 25 mm, sample weight equivalent, thickness of the specimen with any thickness removed between the fulcrum 6 under the atmosphere of 23 ° C. ± 2 ° C. and relative humidity 50 ± 5%. A load is applied up to 90 mm at a distance of 300 mm and a test speed of 20 ± 1 mm / min, and a load deflection curve is recorded. The width was kept constant at 25 mm, and the thickness was adjusted so that the sample weight was equal. The case of a non-foamed resin plate is represented by a load-displacement amount diagram M, and the case of a sample made of a foamed polypropylene 45-fold product is represented by a load-displacement diagram H.

  FIG. 15 shows that although the weight of the samples is the same, bending rigidity is greatly increased by using a foam. Conventionally, it has not been common to bend a foam and use it as a cushioning material. However, by using a foam, the weight of components required to obtain equivalent bending rigidity can be reduced. It is shown that the weight can be reduced.

DESCRIPTION OF SYMBOLS 1 2 layer structure cushion body 2 1st cushion body 2a Support body 2b Leg body 3 2nd cushion body 3a Rod-shaped body 3b Flat plate-like body 3c Net-like foamed resin net 4 Space part 9 Load 10 Skin 11 Seated person 20 Pressure jig 21 Sample plate 30 Means 31 Air flow

Claims (3)

A support body made of a synthetic resin foam having a bending deflection amount of 20 mm or more measured according to the method described in JIS K7221-2: 2006 and a load at the time of 20 mm deflection of 2 to 100 N, and a leg body that supports the support body A first cushion body that receives a load from a seated person or a supine person, forming a space where the support body can be bent and deformed by the support body and the leg body, and
In addition, it has an elasticity of 5 to 200 N / φ100 mm in hardness at the time of 25% compression, and is installed on the seated person or supine side of the support body, covering at least the surface area on the seated person or supine side of the support body, And a second cushion body that receives a load from a seated person or a supine person.   The two-layer structure cushion body according to claim 1, wherein the second cushion body is made of a breathable structure or a breathable material.   Means for creating a state in which stagnant air inside the first cushion body and the second cushion body flows; means for blowing warm air, cold air or dehumidified air into the first cushion body and the second cushion body; And at least 1 or more means of the means which inserts a sheet-like heat generating body in the surface side or back surface side of a 2nd cushion body is provided, The two-layer structure of Claim 1 or 2 characterized by the above-mentioned. Cushion body.

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