JP2006187466A - Cushioning material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cushioning material having favorable cushioning characteristics while maintaining the stability of the user's posture. <P>SOLUTION: When used at a sitting position, the cushioning material is thickest at a portion which is in contact with the tuber of ischum between the central and rear parts of the user's hip and the protrusion of the user's tailbone. Specifically the thickness of the portion contacting the tuber of ischium between the central and rear parts of the user's hip is 120-160% of the thickness of the four corners of the cushioning material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to cushion materials such as bedding, automobile seats, chairs, and cushions, and more particularly to cushion materials that require body pressure dispersibility, such as cushion materials suitable for pressure ulcer prevention.

  Many of the cushion material shapes that enhance the cushioning effect, such as cushions and cushions attached to bedding, chairs, and car seats, have a gentle recess with the back of the buttocks recessed to match the shape of the buttocks. It has a shape. This is considered to take into account the stability of posture, ease of sitting, and impression of appearance.

  When sitting for a long time, the hip joint, which was close to a right angle at the beginning, gradually began to slide forward as the hip joint gradually opened forward to release the feeling of pressure on the sciatic nodule and coccyx that protrudes most in the buttocks. It becomes a seat that is displaced to the shape of "". In order to suppress this, the portion of the cushion material that contacts the back of the buttocks is recessed, and the center of the cushion material is slightly raised according to the shape of the thigh, so that the center of gravity of the weight is placed at the rear, the front of the cushion material and Raising the sides like a bank prevents the thighs and buttocks from sliding and ensures posture stability. In order to secure the above-mentioned practicality and to give a sense of stability and security by making the shape so as to wrap the collar portion, the shape of the cushion material has become the mainstream (Patent Documents 1 and 2).

  However, since the center of gravity of the weight is applied from the center of the buttocks to the rear, the cushion material of the above shape has the thinnest thickness of the cushion material around the sciatic nodule where the body pressure is most applied, and the feeling of pressure applied to the sciatic nodule Is inevitable. In particular, when a sitting posture is forced in a long wheelchair life, pressure ulcers are likely to develop at a site where body pressure is applied. As the aging population increases, the number of people who are forced to use wheelchairs tends to increase in the future, and there is a great need for cushion materials for sitting that have excellent cushioning performance that is devised so that pressure ulcers etc. are less likely to develop. .

One of the external factors of pressure ulcer is body pressure (compressive force) acting in the vertical direction, but in order to remove this pressure, a soft and cushioning material is required. However, if the cushion material is too soft, it is difficult to keep the posture stable, and the portion to which the body pressure is applied is bottomed out. In addition, as one of the causes of pressure ulcer development, the shifting force acting in the horizontal direction is regarded as important. For example, if the posture is bad and it is difficult to maintain a normal sitting posture, etc., or if it is difficult to change the posture by yourself, the displacement force will work while holding the sitting posture for a long time etc. There are many cases. In particular, when a foam cushion material is used, there is a strong tendency for pressure ulcers to occur due to displacement. On the other hand, when a cushion material made of a gel material having high fluidity is used, the absorbing action of the displacement force is high, but it is not desirable for stable holding of the posture. Therefore, research and development have been conducted on new cushion materials such as a combination of a foam material and a gel material, or an intermediate material between the foam material and the gel material. However, there is still a point to be improved about the shape of the cushion material that releases the feeling of pressure on the sciatic nodule and the coccyx part and has a small shift force.
JP 2004-242839 A JP 2001-046438

  This invention is made | formed in view of the said situation, The subject is providing the cushion material which has favorable cushioning properties, maintaining the stability of a attitude | position.

  In order to solve the above-mentioned problems, the present inventors have intensively studied, experimented, and studied, and as for the cushioning material, the part that contacts the sciatic tubercle and the projecting part of the tailbone from the central part of the buttocks is the thickest, The present invention has been found by providing a cushioning material having good cushioning properties while maintaining the stability of the posture when the cushioning material is used, unlike the common sense of .

That is, this invention consists of the following.
1. In the cushioning material including a convex raised shape, when the convex vertex is used in a sitting position, it is provided at a portion that comes into contact with the projecting portion of the sciatic tubercle and coccyx, A cushioning material having a thickness of 120% or more and less than 160% with respect to the thickness of the four corners of the cushioning material.
2. A cushioning material having a thickness at a position selected from the range from the rear end 1/5 to 1/2 of the cushioning material for sitting position of 120% or more and less than 160% with respect to the thickness of the four corners of the cushioning material.
3. 3. The cushion material according to item 1 or 2, wherein the compression modulus value of the cushion material is 40 to 80 N / 314 cm ² .
4). 4. The cushion material according to any one of items 1 to 3, wherein the cushion material is made of a low-resilience polyurethane foam.

  The cushion material of the present invention has good body pressure dispersion, has a relaxation effect against shear stress, has excellent sitting position retention, and is particularly effective in preventing pressure ulcers when used for a long time such as a wheelchair. The present invention increases the thickness of the cushion material at the sciatic tubercle and coccyx where the feeling of pressure due to body pressure is strongest, thereby increasing body pressure dispersibility, and as a result of sinking due to body pressure, the body is kept horizontal and wraps around the buttocks By using a cushion material made of a polyurethane material having a low repulsion and high gel characteristics, it is possible to minimize the generation of displacement force.

When the cushioning material is used, as shown in FIG. 1 or FIG. 2, the body pressure is most applied from the central part of the buttocks to the part where the sciatic tubeross of the rear part and the projection part of the coccyx contact. The cushioning material of the present invention is characterized in that the portion where the sciatic nodule and the projecting portion of the coccyx of the rear part contact from the center part of the buttocks is the thickest when it is in the sitting position.
In general, most of the shape of the cushion material is a rectangular parallelepiped with a flat upper surface in contact with the heel portion or a gently concave shape with the upper surface recessed according to the shape of the heel portion. It has a shape.

  The position of the apex of the convex shape of the cushion material of the present invention is characterized in that it is at the center of the cushion material or behind it, that is, on the heel side. If there is enough bulge on the upper surface, it may be the central part of the cushion material, but in order to further increase the body pressure dispersion efficiency, the sciatic nodule and the cochlear projection part behind the central part of the cushion material in the sitting position It is preferable to provide the position of the convex apex at the site where the contacts. Specifically, it is selected from the range from the rear end 1/5 to 1/2 of the cushion material (see FIG. 5). In order to prevent the body from slipping forward, if the apex position is set forward, that is, on the thigh side, the center of gravity of the body tilts toward the back of the buttocks, and the sciatic nodule and the projection part of the coccyx that receive the most pressure in the sitting position contact The part to be subjected to further pressure.

  The shape of the apex of the convex shape of the cushion material of the present invention can be hemispherical, kamaboko, plateau, or columnar, and is preferably symmetrical. If it is shifted to either the left or right, the upper body is tilted and the posture stability cannot be obtained sufficiently. In particular, when the cushion material is made of a hard material with high resilience or when the four corners of the cushion material are thick, stability is often not obtained.

In the cushion material of the present invention, the thickness (b) of the thickest part (convex apex) is 120% or more and less than 160% of the thickness (a) of the four corners. When the thickness of (b) is less than 120% of the thickness of (a), a sufficient body pressure dispersion effect cannot be obtained. In particular, in the cushion material having the thickness (a) of less than 40 mm, bottoming occurs, and the displacement force may increase.
If the thickness of (b) is 160% or more of the thickness of (a), the height difference between the apex and the four corners of the convex portion is large, so the thigh slips forward and downward when sitting shallowly forward. It is easy, and if you sit back deeply, the coccyx region behind the hips will sink deep, resulting in increased pressure.

If the cushion material of the present invention can be maintained so that the positions of the thigh and the buttocks are substantially horizontal when in the sitting posture, sufficient body pressure dispersion characteristics can be obtained. In order to obtain sufficient body pressure dispersion characteristics in the shape having the thickness of the cushion material described above, the compression modulus value of the cushion material is 40 to 80 N / 314 cm ² , preferably 45 to 65 N / 314 cm ² . Is preferred. If the compression modulus value is higher than 80 N / 314 cm ² , the sciatic nodule site and the coccyx site will be highly repulsive and burdensome. On the other hand, if it is lower than 40 N / 314 cm ² , the coccyx site behind the hips will sink deep, resulting in increased pressure.

  As the material used for the cushioning material having the above properties, polyurethane foam, polyurethane gel, silicon gel, fine beads, etc. that are used for general cushioning materials can be applied. However, materials such as air mats and water beds that cannot be shaped by themselves cannot be applied.

  In view of ease of adjustment of the thickness and shape of the cushion material, weight, breathability, etc., in production, the cushion material of the present invention preferably uses a low-resilience polyurethane foam and a similar material thereto. .

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples, and various applications are possible without departing from the technical idea of the present invention.

The polyisocyanate prepolymer used in the examples and comparative examples of the present specification was synthesized as follows.
(1) Synthesis of polyisocyanate prepolymer A:
Blend 50 parts of 4,4'-diphenylmethane diisocyanate (MDI) and 50 parts of polyol (EO / PO = 75/25, OH number = 56, molecular weight = 3,000) and heat at 80 ° C. with stirring. Thus, polyisocyanate prepolymer A was produced.
(2) Synthesis of polyisocyanate prepolymer B:
Blend 5 parts of tolylene diisocyanate (TDI) and 95 parts of polyol (EO / PO = 70/30, OH number = 7.5, molecular weight = 15,000) and heat at 80 ° C. with stirring to polyisocyanate prepolymer B was produced.

Example 1
18 parts of the polyisocyanate prepolymer A, 28 parts of the polyisocyanate prepolymer B, and 85 parts of polyoxyethyl polyoxypropylated glycerin (EO / PO = 50/50) as a polyether polyol are mixed at 80 ° C. For about 2 hours. Thereafter, the temperature of the reaction solution was lowered to 50 ° C., 3 parts of water was added, stirred and mixed, and then poured into a mold.
The mold was allowed to stand in a horizontal state, and the reaction solution was foamed at room temperature to obtain a foam (top position: center) having a kamaboko upper surface (see FIG. 3). Thereafter, the film was allowed to stand for one day at room temperature to be cured, and then the surface was covered with a 30 μm-thick urethane film to produce a cushion material (about 40 cm × 40 cm × 9 cm, apex height: 13 cm).
As a result, a cushioning material having an upper surface of a semi-cylindrical shape and a vertex height of 144% at four corners was obtained.
The cushion material was measured for density, compression modulus, Max pressure, and displacement force by the following methods, and the results are shown in Table 1.

(Example 2)
The same material as described in Example 1 was used, the mold was allowed to stand at an inclination of 30 °, the reaction solution was foamed at room temperature, and the upper surface was deformed. About 1/3) was obtained (see FIG. 4). Thereafter, the film was allowed to stand for one day at room temperature to be cured, and then the surface was covered with a 30 μm-thick urethane film to produce a cushion material (about 40 cm × 40 cm × 9 cm, apex height: 13 cm).
As a result, a cushioning material having an upper surface of a deformed kamaboko shape and a vertex height of 144% at four corners was obtained.
The cushioning material was measured in the same manner as in Example 1, and the results are shown in Table 1.

(Comparative Example 1)
18 parts of the polyisocyanate prepolymer A, 28 parts of the polyisocyanate prepolymer B, and 85 parts of polyoxyethyl polyoxypropylated glycerin (EO / PO = 50/50) as a polyether polyol are mixed at 80 ° C. For about 2 hours. Thereafter, the temperature of the reaction solution was lowered to room temperature, 3 parts of water was added, stirred and mixed, and then poured into a mold.
The mold was left in a horizontal state, and the reaction solution was foamed at room temperature to obtain a foam having a flat top surface. Thereafter, the film was allowed to stand for one day at room temperature to be cured, and then the surface was covered with a 30 μm-thick urethane film to produce a cushion material (about 40 cm × 40 cm × 9 cm).
The cushioning material was measured in the same manner as in Example 1, and the results are shown in Table 1.

(Comparative Example 2)
18 parts of the polyisocyanate prepolymer A, 28 parts of the polyisocyanate prepolymer B, and 85 parts of polyoxyethyl polyoxypropylated glycerin (EO / PO = 50/50) as a polyether polyol are mixed at 80 ° C. For about 2.5 hours. Thereafter, the temperature of the reaction solution was lowered to 50 ° C., 3 parts of water was added, stirred and mixed, and then poured into a mold.
The mold was allowed to stand in a horizontal state, and the reaction solution was foamed at room temperature to obtain a foam (top position: center) with an upper surface shaped like a kamaboko. Then, after allowing to stand for one day at room temperature and curing, the surface was covered with a 30 μm-thick urethane film to produce a cushioning material (about 40 cm × 40 cm × 7 cm, apex height: 13 cm).
The cushioning material was measured in the same manner as in Example 1, and the results are shown in Table 1.

(Comparative Example 3)
18 parts of the polyisocyanate prepolymer A, 28 parts of the polyisocyanate prepolymer B, and 85 parts of polyoxyethyl polyoxypropylated glycerin (EO / PO = 50/50) as a polyether polyol are mixed at 80 ° C. For about 2.5 hours. Thereafter, the temperature of the reaction solution was lowered to room temperature, 3 parts of water was added, stirred and mixed, and then poured into a mold.
The mold was allowed to stand in a horizontal state, and the reaction solution was foamed at room temperature to obtain a foam having an upper surface of a kamaboko shape. Then, after leaving it to stand at room temperature for one day, the surface was covered with a 30 μm-thick urethane film to produce a cushioning material (about 40 cm × 40 cm × 9 cm, apex height: 10 cm).
The cushioning material was measured in the same manner as in Example 1, and the results are shown in Table 1.

(Test Example 1) Measurement method and evaluation method The cushion materials produced in the above Examples and Comparative Examples were measured and evaluated by the following measurement methods.
(1) Density (Unit: kg / m ³ )
The cushion material obtained by each Example and Experimental example was cut out, and the weight was measured using the electronic balance. The size of the cut cushion material was measured using calipers, and the density was calculated from the weight and volume.

(2) Compression modulus value (unit: N / 314cm ² )
A sample obtained by cutting out the cushion material obtained in each Example and Experimental Example into a size of about 40 cm × 40 cm was used as each test sample.
Using a universal testing machine “Autograph AGS-100”, a 200 mmφ disk was compressed at a speed of 10 mm / min. The load value (N / 314 cm ² ) when the test sample was compressed to 25% of the initial thickness was taken as the compression modulus value.

(3) Max pressure (unit: mmHg)
The “BIG-MAT sensor” made by Nitta Corporation was laid on each cushion material obtained in the examples and experimental examples, and a buttock model (compliant with Japanese Industrial Standard JIS-D-4607) was placed on the cushion material. . The angle of the buttock model was adjusted so that the screwing surface was horizontal. Adjustment was made by placing a weight on the buttocks model so that the load applied to each cushion material was 50 kg including the weight of the buttocks model itself. A body pressure dispersion chart at that time was created, and Max pressure was read from the body pressure dispersion chart.

(4) Displacement force (unit: N)
A buttocks model (a product conforming to Japanese Industrial Standard JIS-D-4607) was placed on each cushion material obtained in the examples and experimental examples. The screw surface of the buttock model was prevented from moving in the horizontal direction, and the weight of the buttock model itself was adjusted to 50 kg, as in (3) above. After leaving it under a load for 30 minutes, measure the distance between the bottom surface of the buttocks model and the bottom surface of the sample. AGS-100 "was used for pulling. The displacement and pressure at this time were read and a displacement-stress diagram was created. The displacement force (25%) when the value corresponding to 25% of the thickness of the test sample before applying the shear force was displaced was obtained from the following formula.

Displacement force (25%) = {(Stress of displacement 30 mm-Stress of displacement 5 mm) / (30 mm-5 mm)} x 0.25 x sample thickness

  In addition, since the calculation result by the above formula has a variation when the displacement is 5 mm or less and there is a possibility of slipping when the displacement is 30 mm or more, the data was obtained when the displacement was between 5 mm and 30 mm. In the case of scale over at a displacement of 30 mm, the slope of the straight line was obtained at a portion where the displacement was 5 mm or more, and the value was calculated by multiplying that value by 25% of the sample thickness.

As shown in Table 1, the cushion material whose upper surface obtained in Example 1 and Example 2 has a semi-cylindrical shape and whose apex thickness is 144% of the thickness of the four corners has any compression modulus, Max pressure, and displacement force. It was also small and excellent in the evaluation of sitting comfort. These cushion materials had a higher displacement force than the cushion materials obtained in the comparative examples, but were suppressed to be lower than those of commercially available low-resilience urethane foams of 70 and 80.
On the other hand, the cushion material of Comparative Example 1 having a flat upper surface had large values of compression modulus and Max pressure, although the displacement force was small. In addition, the cushion material of Comparative Example 2 in which the thickness of the apex is 186% of the thickness of the four corners has a high Max pressure and a high displacement force although the compression modulus is small. The cushion material of Comparative Example 3 having a vertex thickness of 111% of the thickness of the four corners had a large value of compression modulus and Max pressure, although the displacement force was small.
From the above results, it was confirmed that the cushion materials of Examples 1 and 2 of the present invention were superior in sitting comfort compared to the cushion materials of Comparative Examples 1 to 3.

  As described above, the cushioning material according to the present invention has been evaluated for density, compression modulus value, Max pressure (unit: mmHg) and displacement force. It was also confirmed that the burden on the sciatic nodule and coccyx sites with the highest body pressure was reduced. Thereby, the cushion material of this invention can be comfortably used as cushion materials, such as a chair, a motor vehicle seat, and a cushion. It can also be used for medical purposes such as wheelchairs, and is particularly suitable as a cushioning material used to prevent pressure ulcers.

It is an image figure of a sciatic nodule when sitting on a cushion material. It is an image figure of a sciatic nodule when sitting on a cushion material. It is a figure which shows the cushion material of this invention. Example 1 It is a figure which shows the cushion material of this invention. (Example 2) It is sectional drawing of the A-A 'part of the cushioning material of FIG. Example 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cushion material 2 Grow part 3 Sciatic tubercle a Thickness of the four corners of cushion material b Thickness of the convex shape vertex of cushion material

Claims (4)

In the cushioning material including a convex raised shape, when the convex vertex is used in a sitting position, it is provided at a portion that comes into contact with the projecting portion of the sciatic tubercle and coccyx, and the convex vertex portion of the cushioning material A cushioning material having a thickness of 120% or more and less than 160% with respect to the thickness of the four corners of the cushioning material. A cushioning material having a thickness at a position selected from the range from the rear end 1/5 to 1/2 of the cushioning material for sitting position of 120% or more and less than 160% with respect to the thickness of the four corners of the cushioning material. The cushion material according to claim 1 or 2, wherein the compression modulus value of the cushion material is 40 to 80 N / 314 cm ² . The cushion material according to any one of claims 1 to 3, wherein a material of the cushion material is made of a low-resilience polyurethane foam.

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