JP2003235688A - Cushion material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cushion material having superior flexibility, deviation mitigating performance, and body pressure dispersiveness and being effective for bedsore prevention. <P>SOLUTION: This cushion material is formed by stacking sheet structures, which are formed of thermoplastic elastomer and provided with, at least, a plurality of projecting parts in one sides, with their surfaces having the projecting parts facing to each other. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cushioning material for mattresses, wheelchairs, seats, sofas, beds, etc., which is excellent in flexibility, slipping force relaxation, and body pressure dispersibility and is effective in preventing floor rubs.

[0002]

2. Description of the Related Art In recent years, an aging society is rapidly advancing, and the number of people requiring care such as bedridden patients is increasing. In these patients, a certain part of the body is kept in continuous contact with the mat, causing pressure on the skin and subcutaneous tissue, causing a rub on the floor, which causes great pain.

In order to prevent or treat such floor rubs, it is necessary to disperse the pressure exerted on the body contact portion in the vertical direction, that is, to distribute the body pressure. Conventionally, the body pressure is dispersed by controlling the air pressure like an air mat, or the body pressure is dispersed by using water such as a water bed. The method of pressure dispersion was used.

However, it is difficult to adjust the internal pressure of the air mat, and since the air enters too much and the internal pressure of the air cell becomes too high to push back the body, pressure may be applied. There was a case where a part of the bottom of the floor bottomed out, which caused rubbing on the floor. In addition, it is unexpectedly often that the power source of the air pump remains off due to the movement of the bed, and this is one of the causes of floor rub. For water beds, it is effective in terms of high body pressure dispersibility, but if the bag breaks, water will leak out and it will be troublesome to clean up, shaking will make you feel unwell, and because of its large weight, bed mats and cushions There is a problem that it is difficult to carry when it is used as an application mat.

Further, in recent years, not only vertical compression but also horizontal compression, that is, "deviation" has been regarded as an important factor as a main physical factor of floor rub. The force of displacement becomes easier to work if you keep the same posture for a long time,
Shear stress and tensile stress act everywhere inside the tissue in a direction horizontal to the load direction. When such a displacement force is applied, the skin tissue is twisted or deformed by being sandwiched between the surface in contact with the tissue attached to the bone inside the living body and the hard bone. Further, the capillaries are also compressed, and become in a state of being twisted or torn.
Thus, slippage is not a direct cause of pressure ulcers, but is considered a major factor in increasing the impact of pressure ulcer compression. And with conventional materials such as air and water, it is possible to disperse the vertical compression, but it has not been possible to disperse such "deviation" applied in the horizontal direction.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems of conventional mats, and is a cushioning material which is excellent in flexibility, relaxation of slippage force, and dispersibility of body pressure and which is effective for preventing floor rubs. The purpose is to provide.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a sheet-like structure formed of a thermoplastic elastomer and having a plurality of convex portions on at least one surface is By laminating together the surfaces having the convex portions, it is possible to disperse the load in the vertical direction and the horizontal direction, which could not be completely dispersed only by the single-layer sheet-shaped structure, and the cushioning material achieving the above object can be obtained. They have found that they can be obtained and have completed the present invention.

That is, the present invention relates to a cushion material formed by stacking sheet-like structures having a plurality of convex portions on at least one surface and formed of a thermoplastic elastomer so that the surfaces having the convex portions are laminated together.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The thermoplastic elastomer used in the present invention is not particularly limited as long as it is a known thermoplastic elastomer, for example, vinyl aromatic elastomer, urethane elastomer, polyamide elastomer, and the like, One or more of these may be used. Among these, vinyl aromatic elastomers are preferably used because they are flexible and easy to mold. Examples of such a vinyl aromatic elastomer include a block copolymer having at least one polymer block A containing a vinyl aromatic compound as a main component and at least one polymer block B containing a conjugated diene compound as a main component. You can list coalescence. Among these block copolymers, those having a vinyl aromatic compound content of 5 to 70% by weight are preferable, and 70% or more of the carbon-carbon double bonds present in the polymer block B are hydrogenated. Are more preferable. As the molecular structure of the block copolymer, when the polymer block A is represented by "A" and the polymer block B is represented by "B", for example, (A-
B) n, (A-B) n-A [in the formula, n represents an integer of 1 or more], or (A-B) m-X (wherein, X represents a coupling agent residue, m Represents an integer of 2 or more).

Examples of the vinyl aromatic compound constituting the polymer block A in the block copolymer include styrene, α-methylstyrene, o-methylstyrene and m.
-Methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, vinylnaphthalene, vinylanthracene and the like can be mentioned, and one or more of them can be used. Polymer block B in the block copolymer
1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like can be given as the conjugated diene compound constituting Alternatively, two or more kinds are used. The microstructure of the polymer block B mainly composed of the conjugated diene compound is not particularly limited, but its vinylation degree is preferably 70% or less.

In order to obtain a sufficient rubber elastic body in the above block copolymer, the ratio (weight ratio) of the content of the vinyl aromatic compound to the content of the conjugated diene compound is 5/95 to.
It is preferably within the range of 70/30. The number average molecular weight of the block copolymer is not particularly limited, but it is preferably 50,000 to 1,000,000, and more preferably 150,000 to 300,000.

The above block copolymer may be further modified and used by introducing a polar group such as a hydroxyl group, a carboxyl group, an epoxy group or a halogen group into the molecular end or the molecular chain.

The urethane-based elastomer used as the thermoplastic elastomer is not particularly limited as long as it is a known one. For example, it can be obtained by reacting an organic diisocyanate, a polymer diol and a chain extender. I can list things.

Examples of the organic diisocyanate used in producing the urethane elastomer include, for example, 4,
Aromatic diisocyanates such as 4'-diphenylmethane diisocyanate, tolylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, 3,3'-dichloro-4,4'-diphenylmethane diisocyanate; hexamethylene diisocyanate, Examples thereof include aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate. These organic diisocyanates may be used alone or in combination of two or more. You may use together.

As the polymer diol constituting the urethane elastomer, any of the polymer diols conventionally used in the production of thermoplastic polyurethane can be used, and examples thereof include polyester diol, polyether diol, polycarbonate diol, Examples thereof include polyester polycarbonate diol and polyester polyether diol. More specifically, the polyester diol includes, for example, an aliphatic polyester diol obtained by reacting an aliphatic diol with an aliphatic dicarboxylic acid or an ester-forming derivative thereof, an aliphatic diol with an aromatic dicarboxylic acid or an ester thereof. Aromatic polyester diols and the like obtained by the reaction of the forming derivative, polyether diols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol or block copolymers thereof, and polycarbonate diols such as aliphatic diols. For example, a polycarbonate diol obtained by a reaction between a carbonate compound and a polycarbonate diol, a polycarbonate diol obtained by a reaction between an aromatic diol such as bisphenol A and a carbonate compound are used. Rukoto can. These polymeric diols may be used alone or in combination of two or more.

The type of chain extender that constitutes the urethane elastomer is not particularly limited, and any of the conventionally used chain extenders can be used. Among them, the chain extender has a molecular weight of 300 having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule.
The following low molecular weight compounds are preferably used. Examples of such chain extenders include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol. , Bis- (β-hydroxyethyl) terephthalate, xylylene glycol and other diols; hydrazine, ethylenediamine, propylenediamine, xylylenediamine,
Isophoronediamine, piperazine and its derivatives, phenylenediamine, tolylenediamine, xylenediamine, diamines such as dihydrazine adipate and dihydrazine isophthalate, amino alcohols such as aminoethyl alcohol and aminopropyl alcohol, and the like. 1 type (s) or 2 or more types can be used. Among them, aliphatic diols having 2 to 10 carbon atoms are preferably used, and particularly 1,4-butanediol is more preferably used.

The polyamide elastomer used as the thermoplastic elastomer is not particularly limited as long as it is a known one. For example, a hard segment made of polyamide and polyester, polyether, polyester polyether or the like is used. Examples thereof include a copolymer composed of a soft segment.

Examples of the polyamide segment constituting the above polyamide elastomer include ω-aminocaproic acid, ω-aminoenanthic acid, ω-aminocaprylic acid, ω-aminopergonic acid, ω-aminocapric acid, 1
Segments derived from aminocarboxylic acids having 6 or more carbon atoms such as 1-aminoundecanoic acid and 12-aminododecanoic acid; segments derived from lactams such as caprolactam and lauriloractam; ethylenediamine,
1,2-propylenediamine, 1,3-propylenediamine, 1,4-butanediamine, 1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 1,6
-Hexanediamine, 1,7-heptanediamine, 1,
8-octanediamine, 2-methyl-1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-
Diamine components such as dodecanediamine and cyclohexanediamine, and glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid,
Terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene-2,6-dicarboxylic acid, diphenyl-4,4'-
A segment derived from a dicarboxylic acid component such as dicarboxylic acid or diphenoxyethanedicarboxylic acid can be mentioned.

Examples of the polyester segment constituting the polyamide elastomer include a segment derived from hydroxycarboxylic acid such as ω-oxycaproic acid; a segment derived from lactone such as ε-caprolactone; glutaric acid, adipic acid. , Pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene-2,6-dicarboxylic acid, diphenyl-
A dicarboxylic acid component such as 4,4′-dicarboxylic acid or diphenoxyethanedicarboxylic acid, ethylene glycol,
Diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, 1,5-pentanediol, 3 -Methyl-1,5
-Pentanediol, 1,6-hexanediol, 1,
7-heptanediol, 1,8-octanediol, 2
Examples thereof include a segment derived from a diol component such as -methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, cyclohexanedimethanol and cyclohexanediol.

Examples of the polyether segment constituting the above polyamide elastomer include polymethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, and other segments.

Examples of the polyester polyether segment constituting the above polyamide elastomer include a dicarboxylic acid component of the above polyester segment and polymethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, etc. A segment derived from a diol component may be mentioned.

The thermoplastic elastomer used in the present invention may contain a plasticizer, if necessary. Such a plasticizer is not particularly limited as long as it is a known one, but in order to provide a cushioning material that hardly causes bleeding and has a good texture, a non-aromatic mineral oil or liquid or A low molecular weight synthetic softening agent is preferably used. Specifically, natural fats and oils, process oils, liquid paraffin, squalane, isophytol, silicone oil, phthalates,
Polyethylene glycol, polypropylene glycol,
Examples thereof include ethylene glycol, propylene glycol and glycerin. Above all, paraffinic oils can be preferably used because their molecular weight is reasonably large and the viscosity of the oil itself is reasonably low.

The amount of the plasticizer blended is preferably 50 to 2000 parts by weight, more preferably 80 to 1000 parts by weight, based on 100 parts by weight of the thermoplastic elastomer.
If the amount is less than 50 parts by weight, the flexibility may be poor,
If the blending amount exceeds 2000 parts by weight, bleeding of the plasticizer tends to occur.

If necessary, the above thermoplastic elastomer may be blended with, for example, a styrene resin, a polyoxymethylene resin, a polyphenylene ether resin, or the like, or a low molecular weight polyethylene or polyethylene glycol, to the extent that the properties thereof are not impaired. It is also possible to mix such. Furthermore, an inorganic filler may be added for the purpose of cost reduction. Examples of the inorganic filler that can be used for this purpose include talc, calcium carbonate, kaolin, titanium oxide and the like.

Further, if necessary, for the purpose of modifying the thermoplastic elastomer, an antibacterial agent, an antifungal agent, a flame retardant, a pigment, fine hollow particles and the like are added within a range not impairing the physical properties of the thermoplastic elastomer. Good.

When the apparent density of the sheet-like structure constituting the cushioning material of the present invention is small, it tends to be tired and its strength is low, and when it is large, it is heavy and difficult to handle. It is preferably ³ and more preferably 0.5 to 0.8 g / cm ³ .

Further, in order to obtain a sheet-like structure having the above-mentioned apparent density, it is preferable to use a foam produced by using a foaming agent if necessary. Examples of the foaming agent used in the present invention include potassium hydrogen tartrate, sodium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, azodicarbonamide, azobisisobutyronitrile, N,
N-dinitrosopentamethylenetetramine, benzenesulfonyl hydrazide, toluenesulfonyl hydrazide,
A thermal decomposition type foaming agent such as 4,4′-oxybis (benzenesulfonylhydrazide) propane gas can be used.
These may be used alone or in combination of two or more.

The amount of the above-mentioned foaming agent added can be appropriately determined according to the desired expansion ratio, but if the amount is small, it may be difficult to reduce the weight of the cushion material obtained, and if the amount is increased, the foam (sheet) obtained can be obtained. Since the strength of the (shaped structure) may be reduced, it is preferably 1 to 50 parts by weight, more preferably 2 to 20 parts by weight, based on 100 parts by weight of the thermoplastic elastomer.

As a method for blending the above-mentioned various additives with the above-mentioned thermoplastic elastomer, conventionally known methods can be used without any particular limitation, but in order to obtain a homogeneous composition,
It is preferable to knead the respective components in a heat-melted state using a kneading machine such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a Brabender, an open roll, and a kneader. It is also possible to obtain a homogeneous thermoplastic elastomer by dry-blending each component in advance with a mixer such as a Hensyl mixer or a tumbler before melt-kneading and melt-kneading the mixture.

When a thermoplastic elastomer having a rubber hardness of more than 80 is used as the thermoplastic elastomer forming the sheet-like structure,
The obtained cushioning material may become too hard, resulting in poor stress dispersion even when a load is applied, resulting in lack of shock absorption. On the other hand, if a rubber having a rubber hardness of less than 10 is used, the resulting cushion material may become too soft and may not return to its original shape even if the load is removed. Therefore, the preferable rubber hardness is 10 to 80, and more preferably 10 to 70. The "rubber hardness" referred to in this specification is based on ASTM D2240 and is a type 0.
It is a value measured at 25 ° C. using a durometer of 0.

The sheet-shaped structure of the present invention can be molded by a conventionally known method such as extrusion molding, injection molding, hollow molding, compression molding, calender molding.

Hereinafter, the shape of the cushion material of the present invention and the sheet-like structure constituting the cushion material will be described in more detail with reference to the drawings. FIG. 1 is a cross-sectional view of a cushion material according to the present invention, showing a solid, hemispherical convex portion 1
Two sheet-like structures having one side on one side are laminated so that the sides having the convex portions are aligned with each other.

In FIG. 1, when the height of the convex portion 1 indicated by t becomes lower, the cushioning property, the body pressure dispersibility, the deviation, and the friction relaxation property of the obtained cushioning material tend to decrease, while the convex portion 1 When the height of 1 is high, the weight of the obtained cushioning material becomes heavy, it becomes difficult to handle, and the air permeability tends to decrease. Therefore, the height of the convex portion is preferably 5 to 50 mm,
10 to 30 mm is more preferable. Further, the diameter t1 of the convex portion 1
Becomes smaller, the moldability tends to decrease, while
Since the weight of the obtained cushioning material tends to increase and the air permeability tends to decrease as the size increases, the thickness is preferably 10 to 100 mm, more preferably 20 to 60 mm. Further, the height and diameter of the convex portions may be all the same or may be a combination of plural kinds of shapes depending on the use of the cushioning material and the like, but from the viewpoint of formability, the same size is used. It is preferably one.

Regarding the shape of the convex portion, a hemispherical shape shown in FIG. 1, a conical shape shown in FIG. Alternatively, all may have the same shape, or a plurality of types of shapes may be used together. Among these shapes, a hemispherical shape is preferable from the viewpoint of load dispersibility.

The number of convex portions per unit area is small.
Then the load dispersibility tends to decrease, while it increases.
Since there is a tendency for the air permeability and moldability to decrease,
100 / 1000cm^TwoIs preferred, and more preferably
30-70 pieces / 1000 cm ^TwoIs preferred.

In FIG. 1, when the distance between the convex portions indicated by w is small, the air permeability and the moldability tend to be lowered, while when it is large, the body pressure dispersibility, the deviation, and the friction relaxation property are lowered. Therefore, 3 to 20 mm is preferable and 5
-8 mm is more preferable.

The thickness of the sheet shown by t2 in FIG. 1 tends to decrease the formability as the thickness becomes thinner, while the thickness becomes 1-20 mm because the weight increases and the handling property tends to decrease. Preferably 2 to 10 mm
Is.

[0038] In Fig. 1, the total thickness of the cushioning material indicated by t3 tends to be unable to sufficiently disperse the load when the cushioning material becomes thin, while on the other hand, when it becomes thicker, the handleability tends to deteriorate. It is preferably 150 mm, more preferably 20 to 100 mm.

The present invention comprises a sheet-like structure having a plurality of convex portions on at least one surface, and it is important to laminate the sheet-like structures having the convex portions together.
By stacking in this way, when a load is applied to the cushion material, not only the vertical compression but also the horizontal shear stress and tensile stress can be efficiently dispersed. That is, when a sheet-like structure having a plurality of convex portions on one surface is used as a single layer without being laminated as in the present invention, a bottom is easily caused when a load is applied, which causes a floor rub. However, by stacking the surfaces having convex portions together as in the present invention, the sheet-like structure having a plurality of convex portions on one side cannot be completely dispersed when used in a single layer. Since it can disperse pressure in the direction, it can prevent bottoming,
At the same time, it becomes possible to disperse shear stress and tensile stress applied in the horizontal direction. The load distribution in the horizontal direction can be evaluated by measuring the body pressure distribution when a sitting posture is taken for a long time. As a method for laminating the surfaces having the convex portions together, the vertices of the convex portions may be laminated, or the vertices of the convex portions may be shifted and laminated as shown in FIGS. Since the cushioning material is less likely to become tired and the load can be efficiently dispersed, it is preferable to stack the ridges with the apexes of the protrusions shifted as shown in FIGS. 1 and 3.

In the cushion material of the present invention, the entire cushion material can be further covered with a film or cloth. As this film or cloth, for example, those manufactured from vinyl chloride, nylon, polyester, polyurethane, cotton or the like can be used. However, if the film or cloth is hard or has poor elongation, the film or cloth may be rubbed against the skin. A material that is soft and easily deformed is preferable because it may cause rubbing on the floor. Further, the film or cloth absorbs a plasticizer or the like that bleeds from a thermoplastic elastomer, but preferably has such a property that it does not easily leak to the outside. For example, a knitted fabric using spandex made of nylon and polyurethane is preferable. More preferable. Among the woven and knitted goods,
The blending ratio (weight ratio) of nylon / polyurethane is 5 / from the viewpoints of bleeding resistance, cushioning properties and touch.
It is more preferable to use one having a range of 95 to 25/75.

Regarding the shape of the film or cloth for covering the entire cushioning material of the present invention, it may have a single cavity, or may be a series of a plurality of elongated bag-like ones such as an air mat. Further, the thickness of the film or cloth covering the entire cushion material can be appropriately set depending on the weight of the user and the intended use.

If necessary, the film may be directly attached to the surface of the sheet-like structure. That is, if the film is attached, bleeding can be prevented when the plasticizer is added. Further, since the strength of the cushion material itself is increased, the cushion structure can be maintained for a long period of time. As the material that constitutes the film,
For example, polyethylene, polypropylene, polyurethane,
Examples of the material include vinyl chloride, nylon, polyester, and the like. Among them, polyurethane is preferable because it has flexibility.

[0043]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. In the following examples and comparative examples, rubber hardness, body pressure dispersibility and sitting comfort were measured and evaluated by the following methods.

(Rubber Hardness) Measured at 25 ° C. using a type 00 durometer according to ASTM D2240.

(Body Pressure Dispersion) A body pressure dispersion system (BIG-MAT) manufactured by Nitta Co., Ltd. was used. A sensor sheet is laid on the cushioning material, and the subjects (five healthy women aged 20 to 50 years, average weight 50 kg) are in the sitting position and the load is 3
Measure the maximum contact pressure of the buttocks after 0 seconds and 2 hours,
The average value was calculated.

(Siting comfort) Subjects were evaluated on a five-point scale based on the impressions of five healthy females aged 20 to 50. I was very tired after sitting for 1: 2 hours and felt pain in my buttocks. I was a little tired after sitting for 2: 2 hours and I felt a little pain in my buttocks. After sitting for 3: 2 hours, I was not so tired and felt no pain. I didn't get tired after sitting for 4: 2 hours. I wasn't tired after sitting for 5: 2 hours.

Example 1 As a thermoplastic elastomer, a mixture of 80 parts by weight of "Septon 4055" (vinyl aromatic elastomer) manufactured by Kuraray Co., Ltd. and 20 parts by weight of "Septon 4033" manufactured by Kuraray Co., Ltd. Process oil (W
"CARNAT" manufactured by itco Corporation
ION ”) and 2 parts by weight of azodicarbonamide as a foaming agent, and kneading with a single-screw extruder while heating at 150 ° C., and then pouring into a mold to form a plurality of semicircular shapes on one side. A sheet-like structure having convex portions was obtained. In addition, the seat structure is allowed to cool to 100 ° C., and the surfaces having convex portions are brought into contact with each other to form a cushion material (t: 20 mm, t 1: 40 m).
m, t2: 3 mm, t3: 40 mm, w: 6 mm, and the number of convex portions were 46/1000 cm ² . This cushioning material was covered with a spandex bag consisting of 15% by weight of nylon and 85% by weight of polyurethane. The cushion material was used for evaluation by the test method described above.
The results are shown in Table 1.

Example 2 A cushion material having a conical convex portion as shown in FIG. 3 was used in the same manner as in Example 1 except that "Kuramiron 8165" (urethane type elastomer) manufactured by Kuraray Co., Ltd. was used as the thermoplastic elastomer. (T: 20mm, t1: 40m
m, t2: 3 mm, t3: 40 mm, w: 6 mm, the number of convex portions was 46/1000 cm ² ) and prepared with a bag. The cushion material was used for evaluation by the test method described above. The results are shown in Table 1.

Comparative Example 1 The same thermoplastic elastomer as used in Example 1,
Using a plasticizer and foaming agent, a thickness of 45 m as shown in Fig. 4.
A plate-shaped cushion material of m was prepared and covered with a bag. The cushion material was used for evaluation by the test method described above. The results are shown in Table 1.

Comparative Example 2 The same thermoplastic elastomer used in Example 1,
Using a plasticizer and a foaming agent, a sheet-like structure having a plurality of hemispherical convex portions on one surface as shown in FIG. 5 (t: 20 m
m, t1: 40 mm, t2: 3 mm, t3: 23 mm,
w: 6 mm, the number of convex portions was 46/1000 cm ² ) and a single layer of the sheet-like structure was covered with a bag. This cushion material was used for evaluation by the above test method. The results are shown in Table 1.

[0051]

[Table 1]

From Table 1 above, Example 1 corresponding to the present invention
It can be seen that the cushion materials obtained in and 2 efficiently disperse the load not only after 30 seconds but also after 2 hours. The contact pressure immediately after taking the sitting posture, that is, after 30 seconds, mainly evaluates the load applied only in the vertical direction, but when taking the sitting posture for a long time, that is, the contact pressure after 2 hours is The load (that is, the shear force) applied gradually not only in the vertical direction but also in the horizontal direction is also evaluated. In the cushion materials obtained in Examples 1 and 2, the contact pressure after sitting for 2 hours was almost the same as the contact pressure after sitting for 30 seconds. It can be seen that it is also excellent in horizontal misalignment mitigation. Furthermore, the cushioning materials obtained in Examples 1 and 2 did not get tired even when sitting for a long time, and the sitting comfort was good. On the other hand, the cushion materials obtained in Comparative Examples 1 and 2 were already loaded after 30 seconds of sitting than the cushion materials obtained in Examples 1 and 2, and further loaded after sitting for 2 hours. Was there. This shows that not only the dispersibility of the body pressure applied in the vertical direction but also the dispersiveness of the displacement force generated in the horizontal direction when a sitting posture is taken for a long time is low. In addition, Comparative Examples 1 and 2
The cushion material obtained in step 1 becomes very tired when sitting for a long time,
Some felt pain in the buttocks.

[0053]

INDUSTRIAL APPLICABILITY As described above, the cushioning material of the present invention has an effect that not only the load applied in the vertical direction but also the displacement force generated in the horizontal direction when a sitting posture is taken for a long time can be efficiently dispersed. It is a cushioning material that has never been used and is excellent for floor rub prevention.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a cross section of a cushion material according to the present invention.

FIG. 2 is an explanatory view showing a surface having a convex portion of the sheet-like structure which constitutes the cushion material according to the present invention.

FIG. 3 is an explanatory view showing a cross section of a cushion material according to the present invention.

FIG. 4 is an explanatory view showing a cross section of a cushion material obtained in Comparative Example 1.

FIG. 5 is an explanatory view showing a cross section of a cushion material obtained in Comparative Example 2.

[Explanation of symbols]

1 hemispherical convex 2 Sheet-like structure having hemispherical protrusions 3 Hemispherical convex 4 Sheet-like structure having hemispherical protrusions 5 Conical convex part 6 Sheet-like structure having conical protrusions 7 Plate-shaped cushioning material 8 Hemispherical convex 9 Sheet-like structure having hemispherical protrusions

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyomi Ohira             3-3 Doyamacho, Kita-ku, Osaka Kuraray Medica             Le Co., Ltd. F-term (reference) 3B096 AB04 AB09 AD07

Claims (8)

[Claims] 1. Formed from a thermoplastic elastomer,
A cushioning material obtained by stacking sheet-like structures having a plurality of convex portions on at least one surface so that the surfaces having the convex portions are laminated together. 2. The cushion material according to claim 1, wherein the height of the convex portion is 5 to 50 mm. 3. The cushion material as a whole has a thickness of 10 to 150.
The cushion material according to claim 1 or 2 having a size of mm. 4. The cushioning material according to claim 1, wherein the thermoplastic elastomer forming the sheet-shaped structure has a rubber hardness of 10 to 80. 5. The cushioning material according to claim 1, wherein the thermoplastic elastomer is at least one selected from the group consisting of vinyl aromatic elastomers, urethane elastomers and polyamide elastomers. 6. The cushioning material according to claim 1, wherein the thermoplastic elastomer forming the sheet-shaped structure contains a plasticizer. 7. The sheet-like structure is a foam.
Cushion material given in any 1 paragraph of ~ 6. 8. The cushion material according to claim 1, wherein the cushion material is further covered with a film or a cloth.