JPH09285665A - Seat cushion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve air permeability and stress distribution capability by specifying the air permeability of an upper cloth and coating rubber on an under cloth which cover a cushion composite consisting of an upper layer which is made of a woven knit fabric layer and a lower layer which is made of a resin foaming layer or single fiber aggregate layer. SOLUTION: This cushion for seating is structured in such a manner that a cloth covers a cushion composite in 40 to 100mm thickness consisting of an upper cushion layer which is made of a woven knit fabric layer and the lower cushion layer which is made of a resin foaming layer or short fiber aggregate layer. The average thickness of the woven knit fabric layer is determined to be 5 to 50mm, 10 to 30mm is recommended, and its air permeability is determined to be 20 to 300cc/cm<2> /sec, 40 to 250cc/cm<2> /sec is recommended. The air permeability of the cloth as the upper surface of the cushion composite is preferred to be more than 20cc/cm<2> /sec. The cloth as the bottom surface of the sheet cushion is coated with rubber or resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat cushion that is resistant to stuffiness when used and has excellent stress dispersion. More specifically, the present invention provides a woven / knitted layer on the upper layer portion,
The resin foam layer or the short fiber aggregate layer is laminated on the lower layer portion and covered with a side material, which is excellent in air permeability and stress dispersibility,
The present invention relates to a seat cushion that can be suitably used as a wheelchair cushion, an office chair cushion, and the like.

[0002]

2. Description of the Related Art Conventionally, as cushion materials for seats,
In addition to a cushion material made of a resin foam represented by urethane foam, an air cushion made of rubber, a gel-like mat, a cushion material made by fusing and bonding short fibers with a low melting point component to form an aggregate (Japanese Patent Application Laid-Open No. HEI-HEI-KAI). No. 5-76388),
Cushion materials (Japanese Patent Laid-Open No. 6-128837) in which a three-dimensionally structured fabric is formed by using highly shrinkable yarns as warp yarns in a multi-woven structure are known. However, each of these cushioning materials has drawbacks in actual use, and further improvement is desired.

For example, a cushion material made of a resin foam has been proposed in which unevenness is applied to the surface to disperse the compressive stress pressure. However, urethane foam has a large initial compression modulus and then rapidly. Since it has a unique characteristic that the modulus is lowered, it has a drawback that not only is it poor in cushioning property, but also it has a large bottoming feeling and tends to get damp.

Although the rubber air cushion is excellent in the dispersibility of stress, it has a drawback that it is apt to be stuffy because the movement of humidity is blocked, and the gel mat is
Although the stress dispersibility is excellent under low load, the dispersibility deteriorates as the load increases and not only high pressure parts occur but also because it is covered with a non-moisture permeable film-like sheet. It has the drawback that it gets stuffy easily.

On the other hand, in the case of a short fiber aggregate, if the short fiber fineness and density cannot satisfy the stress dispersibility and air permeability at the same time, it tends to cause a stuffy feeling.
In addition, local deformation is likely to occur and durability is poor. Also, in the case of a three-dimensional structure fabric with a multiple woven or knit structure, the feeling of stuffiness is unlikely to occur because it has excellent ventilation capacity during use, but there is a technical limit to the thickness of the cushioning material, and the cushioning property is limited. And stress dispersibility tends to be insufficient.

As described above, when the conventional cushion material is used as a cushion for a wheelchair, a cushion for an office chair, etc., the cushion material sufficiently absorbs and releases moisture due to heat and sweat generated from the human body and has a uniform pressure distribution. However, the seat cushion does not satisfy the desired conditions as a seat cushion having excellent durability, and there is a problem that the seat cushion is easily displaced when it is mounted on a chair or the like.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the drawbacks of the conventional seat cushions described above, and is excellent in cushioning property, uniformity of pressure distribution, breathability and durability, and provides a feeling of dampness when worn. It is an object of the present invention to provide a new seat cushion that is less likely to occur, and is less likely to cause pain and blood flow obstruction due to stress concentration during wearing, and is also excellent in wearability to a seat.

[0008]

The object of the present invention is to use a cushion layer A made of a woven or knitted layer as an upper layer and at least one cushion layer B made of a resin foam layer or a short fiber aggregate layer as a lower layer. A seat cushion, which is obtained by covering a cushion composite body having an overall thickness of 40 to 100 mm with a cloth, and the air permeability of the upper cloth of the seat cushion is 20.
cc / cm ² / sec or more, while it is achieved by a seat cushion in which the surface of the lower fabric is coated with rubber or resin.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The seat cushion of the present invention has a cushion layer A made of a woven or knitted layer as an upper layer and at least one cushion layer B made of a resin foam layer or a short fiber aggregate layer as a lower layer. The composite is covered with a cloth. The average thickness of the woven / knitted layer is 5 to 50 m.
m, preferably 10 to 30 mm is suitable, and if it is less than 5 mm, cushioning property is apt to deteriorate and a rough feeling is likely to occur, and air flowability is apt to be decreased to cause stuffiness. On the other hand, if it exceeds 50 mm, the sinkage during use tends to be large, and the productivity thereof will also decrease. The air permeability of the woven / knitted layer is preferably in the range of ^{20 to} 300 cc / cm ² / sec, particularly 40 to 250 cc / cm ² / sec. Below this range, ordinary short fiber aggregates and resin foams are formed. Similar to a cushion, it tends to cause a high degree of stuffiness when used. On the other hand, if the air permeability becomes too high,
I feel cold because the air circulation is so good.

The 25% compression hardness of the woven / knitted layer is 5 to 5
The range of 0 kg is suitable, and if it is less than this range, it is too soft and a bottoming feeling occurs, and the durability (settling resistance) also decreases. On the contrary, when exceeding this range,
If it is too hard, the stress distribution will be insufficient and stress concentration will occur easily.

As the woven and knitted layer having such characteristics,
For example, the three-dimensional multi-woven knitted fabric previously proposed by the present inventors (Japanese Patent Application No. 7-10033 and Japanese Patent Application Laid-Open No. 7-90757),
The three-dimensional Russell knitted fabric proposed in Japanese Utility Model Publication No. 1-136191 can be exemplified. Among them, the former three-dimensional multiple weave design is composed of a surface layer portion and an intermediate layer portion, and the intermediate layer portion has one or two layers having a large number of communicating hollow portions parallel to one direction. It is preferable to use a woven or knitted layer formed by laminating more than one layer.
In particular, it is preferable that a corrugation, particularly a corrugated corrugation having an average height of 2 to 15 mm and an average width of 2 to 30 mm, is formed on one or both surfaces of the surface layer portion because the stress dispersibility is further improved.

The three-dimensional multi-woven structure is substantially composed of filament fibers, for example, polyester fibers, polyamide fibers, aromatic polyamide fibers, etc. are used. Two or more kinds of these fibers may be used in combination, but in that case, it is preferable to use a polyester fiber and a nylon fiber in combination. The filament fiber may be either a monofilament or a multifilament, but the warp fibers constituting the woven structure are
Nylon fibers having a good deformation recovery property are particularly preferable. The single yarn fineness (fineness of yarn) is preferably in the range of 100 to 1000 denier.

The cushion layer A of the present invention has an extremely high porosity of 90% or more, preferably 90% or more, by having a three-dimensional multi-woven structure substantially composed of filament fibers and three-dimensionally organized as described above. Can be 93% or more, and it is possible to provide a cushion composite which is extremely lightweight as a whole.

Next, the other cushion layer B constituting the seat cushion of the present invention may be a resin foam layer or a short fiber aggregate layer, but its average thickness is 10
It is preferably in the range of -60 mm, particularly 30-50 mm, and the 25% compression hardness is preferably in the range of 5-50 Kg. If the thickness is less than 10 mm, the cushioning performance is deteriorated and the stress dispersion tends to be insufficient, and conversely, if it exceeds 60 mm, the subsidence tends to be large. If the compression hardness is less than the above range, it will be too soft and will give a feeling of bottoming and durability (sag resistance).
On the other hand, if it exceeds the above range, it is too hard and the stress dispersion becomes insufficient and stress concentration is likely to occur.

The material of the foamed resin layer used for the cushion layer B is not limited, but
In particular, urethane resin is preferable because it has excellent cushioning performance durability, and for example, Toyo Franc 360 manufactured by Toyo Tire & Rubber Co., Ltd. can be exemplified.

Further, as the short fiber aggregate layer, a fiber cushion material obtained by fusing and integrating the low melting point adhesive short fibers, in particular, short fibers having a thermoplastic elastomer on the fiber surface are dispersed and mixed. The short fiber aggregate layer which is formed by fusion bonding of the elastomer is excellent in its elastic performance and durability, and thus is preferable. Examples of such short fiber aggregate layers include WO91-1903.
No. 2 cushion material, that is, a thermoplastic elastomer having a melting point of 40 ° C. or more lower than the melting point of the polyester constituting the short fibers in the short fiber aggregate by using a matrix of the non-elastic polyester short fiber aggregate. It is possible to use a cushion layer composed of a short fiber aggregate in which short fibers having at least the above are mixed and fused and integrated. Here, the single fiber fineness of the short fibers is 4 denier or more, preferably 4 to 500 denier, and particularly 8 to 30.
0 denier is desirable, and if the fineness is less than 4 denier, the cushioning property tends to deteriorate. If the fineness is too large, the number of constituent fibers in the obtained fiber assembly will be too small, and the cushioning performance will be insufficient. The number of crimps is 4 to 25 / inch, the crimping degree is 20 to 40%,
The fiber length is advantageously about 10 to 100 mm.

On the other hand, the thermoplastic elastomer having a low melting point for fusing and integrating the short fiber aggregates is not particularly limited as long as it has a melting point of 40 ° C. or more lower than the melting point of the polyester short fibers. From the viewpoint of performance and adhesiveness with short fibers, it is preferable to use a polyester-based elastomer, for example, a polyester-based elastomer obtained by copolymerizing a polyester elastomer as a hard segment with a thermoplastic polyester as a soft segment and polyoxyalkylene glycol as a soft segment. Of these, a polyether ester block copolymer having polybutylene terephthalate as a hard segment and polyoxytetramethylene glycol as a soft segment is preferable.

Short fibers containing the low melting point elastomer are
Although it depends on the compression hardness required for the cushion layer B, the fineness of the single fiber is usually 2 to 100 denier, the fiber length is 10 to 100 mm, and the number of crimps is about 4 to 25 pieces / inch. Further, the mixing ratio of the low melting point fiber is appropriately about 10 to 70% by weight based on the weight of the short fiber aggregate.

The overall thickness of the cushion composite having the above-mentioned cushion layer A as the upper layer and at least one cushion layer B as the lower layer is 40 to 100 mm, preferably 60.
It is necessary to set it to -80 mm. If the thickness is less than this range, the stress dispersion is insufficient, and numbness and blood flow obstruction are likely to occur, and the cushioning property is also deteriorated, which is not preferable. On the other hand, if the thickness exceeds the above range, the subsidence becomes too large and the handleability also deteriorates, which is not preferable.

Next, in the cloth covering the above-mentioned cushion composite, if the air permeability of the cloth to be the upper surface of the seat cushion is too small, the movement of humidity will be hindered and a stuffy feeling will occur. 20 cc / cm ² / sec or more,
It is preferably 40 to 250 cc / cm ² / sec. On the other hand, the cloth on the surface of the seat cushion bottom needs to be coated with rubber or resin. If nothing is coated on this portion, it is not preferable because the seat cushion is less attachable and is easily displaced from the main body.

[0021]

The present invention will be described more specifically with reference to the following examples. The properties of compression hardness, air permeability and stress distribution in the examples were measured by the following methods.

<Compression hardness> JIS K 6401 5.
According to the method described in 4.2, using a compression plate, 50 mm
Compressed at a speed of / min, the load is 110 kg (pressure 350 g
/ Cm ² ) and then unload at the same speed. This operation was repeated twice, and the compression hardness was calculated from the following equation from the compression length-stress curve drawn during the second measurement. 25% compression hardness: compression length (sample thickness x 0.25) mm
Load at time [Kg]

<Air permeability> According to the method described in JIS L 1079 (Fragile type air permeability tester), the differential pressure is 1
The air was sucked in to become 1/2 inch, and the amount of air flowing per unit area / unit time at that time was determined.

<Stress distribution> Tactile sensor GSCAN system (BIG-MAT) manufactured by Nitta Co., Ltd.
The stress distribution around the sacrum (buttock) in the sitting posture was measured.
The size of the pressure sensor is 43 cm x 48 cm,
The distance resolution is 10 mm.

[Example 1] A single fiber fineness of 4 denier, a total fineness of 1000 denier, an intrinsic viscosity of 0.8, and a strength of 5.5 g, which consisted of a polyethylene terephthalate polymer in which 13 mol% of an isophthalic acid component was copolymerized. / D, a boiling water shrinkage rate of 50%, and a thermal stress value of 0.52 g / d as a highly shrinkable yarn as a warp, three layers (19 layers / inch for each layer),
4 layers of polyester monofilament 330 denier (30 layers / inch for each layer), polyester false twisted yarn 47
When using 5 denier / 144 filaments as the outermost layer (36 layers / inch for each layer), each of which was wound into 3 beams and formed into a triple beam warped product, a modified 5-layer weave was produced using a rapier loom.
475 denier / 144 filament polyester false twisted yarn was used for the outermost weft yarn, and 300 denier polyester monofilament was used for the four weft yarns of the intermediate layer part to obtain a woven fabric in a total of 60 yarns / inch. .
The obtained woven fabric is set at 150 ° C. for about 10 minutes and contracted by 38% in the length direction of the woven fabric to form a cushion layer A (air permeability of 180 cc / cm ²⁾ composed of a fiber woven fabric layer having a thickness of 30 mm.
/ Sec, 25% compression hardness was 23.5 Kg).

38 wt% of a hard segment consisting of an acid component having a mixing ratio of terephthalic acid and isophthalic acid of 80/20 (molar ratio) and butylene glycol, and a soft segment 62 consisting of polytetramethylene glycol (average molecular weight 2000). Block copolymerized polyether polyester elastomer (melting point 155
℃, the elongation at break in the film is 1500%) as the sheath part, and polybutylene terephthalate as the core part, the core / sheath composite ratio is 50/50 (weight), the single fiber fineness is 9 denier, and the fiber length is 51 mm, 40% by weight of elastic composite fiber having a crimp number of 11 pieces / inch, hollow fiber polyethylene terephthalate fiber (melting point 259 ° C.) having a single fiber fineness of 14 denier, a fiber length of 64 mm, and a crimp number of 9 pieces / inch. % By weight was mixed with a card, and the mixture was put in a flat-plate mold so that the thickness was 30 mm and heat-treated at 200 ° C. for 10 minutes to obtain a cushion layer B composed of a short fiber aggregate layer. The 25% compression hardness of this short fiber structure layer was 15 kg.

Cushion layer A and cushion layer B thus obtained
Is laminated, and the upper surface of the seat cushion is covered with a cloth having an air permeability of 35 cc / cm ² / sec, and the lower surface is covered with a cloth coated with 20 g / m ² of chloroprene rubber. Got the cushion. The obtained cushion had little stuffiness during use, good stress dispersibility, and excellent wearability during use. The evaluation results of this seat cushion are summarized in Table 1.

[Example 2] The cushion layer B has a thickness of 40 mm, a 25% compression hardness of 13 kg, and an air permeability of 25.
A seat cushion was obtained in the same manner as in Example 1 except that urethane foam of cc / cm ² / sec was used. The evaluation results of this cushion are shown in Table 1.

Comparative Example 1 The fiber fabric layer used in Example 1 alone was covered with the same fabric as used in Example 1 to obtain a seat cushion. This product was good with almost no stuffiness during use, but stress-concentrated portions were observed. The evaluation results of this cushion are shown in Table 1.

Comparative Example 2 The short fiber aggregate layer used in Example 1 alone was covered with the same fabric as used in Example 1 to obtain a seat cushion. This product had good air permeability and handleability, but had a hard surface and poor cushioning properties. The evaluation results of this cushion are shown in Table 1.

[0031]

[Table 1]

[0032]

Since the seat cushion of the present invention is composed of a composite body in which a woven / knitted layer and a short fiber aggregate layer or a resin foam layer are laminated, it has excellent stress dispersibility during use and numbness. Since the upper surface is covered with a cloth with good air permeability, while the lower surface is covered with a cloth coated with rubber or resin, there is little stuffiness during use, and It has excellent wearability.

Therefore, by making use of these characteristics, it becomes possible to deal with fields such as cushions for wheelchairs and cushions for office work.

Claims (5)

[Claims] 1. A cushion layer A made of a woven or knitted layer is used as an upper layer, and at least one cushion layer B made of a resin foam layer or a short fiber aggregate layer is used as a lower layer.
A seat cushion in which a 00 mm cushion composite is covered with a fabric, wherein the upper fabric of the seat cushion has an air permeability of 20 cc / cm ² / sec or more, while the lower fabric has no rubber or resin on its surface. Coated seat cushion. 2. The average thickness of the cushion layer A is 5 to 40 m.
m, air permeability of 20 to 300 cc / cm ² / sec, 25
The seat cushion according to claim 1, having a% compression hardness of 5 to 50 kg. 3. The cushion layer B uses a polyester short fiber aggregate having a single fiber fineness of 4 denier or more as a matrix, wherein the short fiber aggregate has a melting point of 40 ° C. or higher than the melting point of the polyester constituting the short fiber. A cushion layer in which short fibers having a low melting point thermoplastic elastomer at least on the fiber surface are dispersed and mixed, and the short fiber aggregates are integrated by fusion bonding of the thermoplastic elastomer.
Seat cushion described. 4. The cushion layer B has an average thickness of 10 to 60.
The seat cushion according to claim 3, having a mm and 25% compression hardness of 5 to 50 kg. 5. The cushion layer B has an average thickness of 10-6.
0 mm, 25% compression hardness 5-50 kg, air permeability 20
The seat cushion according to claim 1, which is a urethane foam layer having a cc / cm ² / sec or more.