JP2010139064A - Shock absorbing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-performance shock absorbing material improved in shock absorbing performance, and capable of enlarging applicable usage by reducing the thickness and volume of the shock absorbing material. <P>SOLUTION: The shock absorbing material is formed by sealing a porous body having a gas adsorption and desorption function and gas in a bag body made of a flexible material so as to form a sealed space. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a shock absorber. More specifically, the present invention relates to a shock absorber formed by enclosing a porous body having a gas adsorbing / desorbing function in a bag made of a flexible material and gas and forming a sealed space. The present invention relates to a shock absorber using gas adsorption / desorption.

  Shock absorbers are being developed and utilized in various fields of application, taking advantage of the characteristics of the materials. The outline of the shock absorbing material and its uses are as follows.

  (1) Shock absorbers made of foam made of thermoplastic resin such as polystyrene, polyethylene, polypropylene, polyurethane, etc. are often used for walls, fences, helmet linings, interior materials for vehicles and aircraft, and bumpers. ing.

  (2) When packing broken objects such as glass, a corrugated cardboard structure in which synthetic resin foams such as polystyrene and polyurethane, flat synthetic resin sheets or cardboard and corrugated synthetic resin sheets or cardboard are laminated (corrugated) A plate material having processing) is used as a cushioning material, and this is inserted into the gap between the packaging box and the cracked object to prevent breakage due to impact generated during transportation.

(3) For synthetic materials such as wall materials and floor materials, or facilities and rock sheds where impact loads such as blast and underwater impacts are applied, the above synthetic resin foam or synthetic resin molding formed into a honeycomb structure is used alone. There are also examples in which these are used in combination.

However, each of these includes problems to be overcome. For example, in the case of (1), in the case of an impact absorbing material made of a synthetic resin foam such as a shock absorbing material having a honeycomb structure or a corrugated structure or a polyurethane foam, when the impact force is applied, the impact absorbing material itself While absorbing a shock in the process of gradually deforming and collapsing while maintaining a certain strength, once the shock is absorbed, it will not return,
There is a problem that the performance before receiving an impact is not guaranteed.

In addition, the impact absorbing material of (2) above receives impact force because it absorbs impact force in the process of gradually deforming and collapsing while maintaining a certain strength itself. Sufficient shock absorbing performance is not exhibited at the moment, and for this reason, for example, when this shock absorbing material is used as a cushioning material for packing, there is a problem that the contents are damaged.

  Further, among the shock absorbers of the above (3), the shock absorbing material having a honeycomb structure or a corrugated structure is extremely complicated to process. Synthetic resin foam, on the other hand, has the advantage that it is easy to manufacture and process, and has excellent handleability, but it is brittle and easily damaged, and easily deteriorates due to contact with heat, light, and solvent. There is.

On the other hand, in applications such as vehicle airbags and shoe soles, a liquid such as water, a gas such as air, or a gel-like substance is enclosed in a case made of a flexible sheet material, and the impact force applied to the case is applied. Is devised to absorb the air, water, or gel-like material contained in the case by deformation, shoes air sole, various cushions, bedding mattress, cushioning material,
Bag materials made of plastic film or the like are widely used as cushion materials for applications such as industrial air dampers. Impact absorbers using air, water, or gels are expected to be expanded in the future because they have excellent resilience for impacts and good handling and durability.

  Examples of shock absorbers using air, water, and gel-like materials include high molecular organic materials such as block copolymers made of polystyrene and ethylene-butadiene random copolymers as impact absorbers containing polymers. In a polymer blend material composed of a low molecular weight organic material such as polyisobutylene, a material in which the content of the high molecular organic material is reduced is used as a shock absorbing material (see Patent Document 1), and liquid or gel is formed by an injection molding method. A method of injecting and molding a substance into a shoe sole (see Patent Document 2), an impact absorbing material in which a resin microballoon is mixed in an ultra-soft urethane elastomer (see Patent Document 3), and a curing accelerator in a synthetic resin There is known a shock absorbing material (see Patent Document 4) in which microcapsules encapsulating the material are dispersed. In addition, an impact absorbing material made of a foamed molded article that does not contain a polymer is also known (see Patent Document 5).

  However, in the shock absorber using air, water, or gel, it has a resilience and has the advantage that excellent shock absorption performance is exhibited every time an impact is applied. Since air, water, or a gel-like material is confined in the case, a certain thickness and volume are required to ensure a predetermined shock absorbing performance, and there are restrictions on applicable applications.

  As mentioned above, shock absorbers using air, water, and gel-like materials are excellent in resilience for impact and have good handleability and durability. It is difficult to say that the performance is still sufficient, and there is a demand for a shock absorbing material with improved performance.

  Activated carbon is excellent in the ability to adsorb various pollutants, and has been used in various fields for both home and industrial use, but activated carbon is known to absorb energy. Can be considered. As an example of activated carbon absorbing energy, for example, there is a method in which an adsorbent is filled between an inner pipe and an outer pipe to reduce pulsation in a pipe such as city gas to be supplied. Has a feature that it has an excellent gas storage amount and can store a substantially large amount of gas as compared with a normal air tank (Patent Document 6).

  Also known is a pressure fluctuation mitigation member for reducing tunnel micro-pressure waves generated when a high-speed moving body such as a Shinkansen vehicle enters the tunnel. (Patent Document 7).

  Further, a speaker device including a speaker unit, a cabinet, a gas adsorber, and a spherical elastic body is known, and it is described that the bass reproduction performance is improved by the gas adsorber (Patent Document 8). .

  However, the method for reducing pulsation disclosed in Patent Document 6 is a method for reducing pulsation in piping in a gas flow system, and the pressure fluctuation reducing member disclosed in Patent Document 7 is a tunnel micro-pressure wave in an open system. The speaker device disclosed in Patent Document 8 is intended to improve bass reproduction performance in an open system, and absorbs and releases the impact of activated carbon enclosed in a bag. There is no such suggestion.

  On the other hand, in a closed system, includes a package subject to gas partial pressure fluctuation, a gas barrier packaging material covering the package, and a buffer material interposed between the package and the packaging material. A package is known, and it is described that the gas concentration in a package such as a carbonized Ringer infusion bag can be maintained within a predetermined range, and the quality of the package can be kept constant (Patent Document 9).

Japanese Patent Laid-Open No. 07-177901 Japanese Patent Application Laid-Open No. 07-32511 Japanese Patent Laid-Open No. 08-323071 JP 2005-68288 A JP 2007-99962 A JP 2005-331053 A JP 2006-22526 A JP 2007-288712 A JP-A-11-79253

  The package disclosed in Patent Document 9 is a closed system, but a buffer material is interposed between an object to be packaged and the packaging material, and the gas concentration in the package is maintained within a predetermined range by the buffer material. It is intended to keep the quality of the packaged body constant, and does not absorb and release shocks by activated carbon sealed inside the packaged body.

  Rather than using conventional air, water, or gel, it is expected that a shock absorber with improved performance can be obtained if the activated carbon can make good use of absorbing energy. Therefore, the purpose of the present invention is to further expand the applicable applications by developing a high performance shock absorber with improved shock absorption performance in a closed system, and further reducing the thickness and volume of the shock absorber. It is to provide a shock absorbing material.

  As a result of intensive investigations by focusing on shock absorbers using gas adsorption and desorption by a porous body, the present inventors have achieved a gas adsorption and desorption function in a bag body made of a flexible material. It has been found that the above object can be achieved by a shock absorbing material in which a porous body having gas and gas are enclosed to form a sealed space, and the present invention has been achieved. The present invention provides the following.

[1] A shock absorber formed by enclosing a porous body having a gas adsorption / desorption function and a gas in a bag made of a flexible material to form a sealed space.
[2] The pressure when the volume of the sealed space is reduced by 50% by the presence of the porous body W (g) is P2 (kg / cm ² ), and the volume of the sealed space is 50 without the presence of the porous body. The impact-absorbing material according to [1], wherein (P1-P2) / W is 0.01 (kg / cm ² · g) or more, where P1 (kg / cm ² ) is the pressure when% reduction is performed.
[3] The impact absorbing material according to [1] or [2], wherein the porous body is activated carbon.
[4] The impact absorbing material according to [3], wherein the activated carbon has a cumulative pore volume of 0.15 to 1.0 ml / g with a pore radius of 20 mm or less.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a shock absorber formed by enclosing a porous body having a gas adsorption / desorption function and a gas into a bag body made of a flexible material to form a sealed space. . According to the shock absorbing material of the present invention, the thickness and volume of the shock absorbing material can be reduced, and further performance enhancement can be realized. The present invention can be preferably applied to the use.

2 is a cumulative pore volume curve and a pore distribution curve of activated carbon used in Reference Examples 1 and 2. FIG. It is a graph which shows the adsorption / desorption effect with respect to the gas of the activated carbon used by the reference examples 1 and 2. FIG. It is a graph which shows the adsorption / desorption effect with respect to the gas of the activated carbon used by the reference examples 3 and 4. FIG. It is a graph which shows the adsorption / desorption effect with respect to the gas of the activated carbon used by the reference examples 6 and 7. FIG.

  The present invention is an impact-absorbing material in which a sealed body is formed by enclosing a porous body having a gas adsorption / desorption function and a gas in a bag made of a flexible material. In the impact absorbing material of the present invention, the porous body is preferably sealed in an amount of 2 to 15 g per 100 ml of the sealed space volume.

The impact absorbing material of the present invention has a pressure of P2 (kg / cm ² ) when the volume of the sealed space is reduced by 50% in the presence of the porous body W (g) from the viewpoint of achieving an excellent impact absorbing effect. ), When the pressure when the volume of the sealed space is reduced by 50% without the presence of the porous body is P1 (kg / cm ² ), (P1-P2) / W is 0.01 (kg / cm ² · g) or more is preferable, and 0.03 (kg / cm ² · g) or more is more preferable.

As such a porous body, various materials can be used as long as they have a gas adsorption / desorption function. Having a gas adsorption / desorption function means a porous body that not only adsorbs gas but also desorbs, for example, activated carbon, zeolite, silica, silica gel, silica-titania, zinc oxide, ceramic, pumice, etc. Can be mentioned. Of these, activated carbon is preferable.

  The activated carbon is not particularly limited, and normal activated carbon obtained by sufficiently carbonizing the carbonaceous material and then activating by a method such as gas activation or drug activation can be used. The carbonaceous material for producing activated carbon is not particularly limited, and mineral materials, plant materials, synthetic materials, and the like are used.

  Examples of mineral materials include coal / petroleum materials (coal pitch, coke, etc.). Examples of plant materials include wood, charcoal, fruit shells (coconut shells, etc.) and various fibers. Synthetic materials include various synthetic resins, specifically, polyamide resins such as nylon, polyvinyl alcohol resins such as vinylon, acrylic resins, polyacrylonitrile resins, polyolefins such as polyethylene and polypropylene. Examples thereof include polyurethane resins, polyurethane resins, phenol resins, and vinyl chloride resins. Examples of the various fibers include natural fibers such as cotton and hemp, regenerated fibers such as rayon and viscose rayon, and semi-synthetic fibers such as acetate and triacetate.

Of the carbonaceous materials, plant-based materials and synthetic-based materials are particularly preferable.
Phenolic resins are preferably used. Two or more kinds of carbonaceous materials may be mixed and used. The shape of the carbonaceous material is not particularly limited, and materials having various shapes such as a granular shape, a powder shape, a fiber shape, and a sheet shape can be used. The granular material may be crushed or granulated. Examples of the fibrous and sheet-like carbonaceous materials include sheet processed products such as woven fabric, non-woven fabric, film, felt, paper, and molded plate.

  Activated carbon can be produced by carbonizing and activating a carbonaceous material. The conditions for carbonization are not particularly limited. For example, in the case of a granular carbonaceous material, conditions such as processing at a temperature of 300 ° C. or higher while flowing a small amount of inert gas through a batch-type rotary kiln are adopted. be able to.

  As described above, the activation method after carbonizing the carbonaceous material may employ any method such as gas activation and drug activation, but it has high mechanical strength and obtains activated carbon having the predetermined pore diameter. In terms of gas activation, gas activation is preferably employed. Examples of the gas used in the gas activation method include water vapor, carbon dioxide gas, oxygen, LPG combustion exhaust gas, or a mixed gas thereof. In consideration of safety and reactivity, a water vapor-containing gas (a gas containing 10 to 50% by volume of water vapor) is preferable.

  The activation temperature is 700 ° C to 1100 ° C, preferably 800 ° C to 1000 ° C. However, the activation temperature, time, and rate of temperature increase are not particularly limited, and vary depending on the type, shape, size, desired pore size distribution, etc. of the carbonaceous material selected. Activated carbon obtained by activation can be used as it is, but in practice, it is preferable to remove the adhering component by acid washing, water washing or the like.

The activated carbon thus obtained can be in the form of particles, sheets, etc., depending on the shape of the carbonaceous material. Or you may grind | pulverize this further. As the particulate activated carbon, those having a desired particle diameter are used as necessary from granular particles having a certain size to fine powders. The sheet-like activated carbon may be in the form of a fabric, felt, paper, plate or the like.

  The particle size of the granular activated carbon is usually 0.05 to 1.0 mm, preferably 0.1 to 0.3 mm. When the activated carbon is in the form of a fabric, the thickness is usually 0.1 to 2.0 mm, preferably 0.3 to 1.0 mm. An activated carbon fabric having a thickness of less than 0.1 mm is difficult to handle due to its low strength, and an activated carbon fabric having a thickness exceeding 2.0 mm is difficult to produce. In the case of a felt shape, a paper shape, or a plate shape, the thickness is usually 0.1 to 10 mm, preferably 0.3 to 5.0 mm.

The activated carbon having a function of adsorbing and desorbing a gas present in the sealed space has a BET specific surface area measured by adsorption of nitrogen gas on the surface thereof in the range of 700 to 3500 m ² / g, more preferably 1000 to 2500 m ² / g. Those are preferred. When the specific surface area of the activated carbon is smaller than this range, the air absorption / desorption performance is insufficient, and thus the impact absorption may be insufficiently improved. On the other hand, when the specific surface area of the activated carbon is larger than this range, it is difficult to obtain the activated carbon, which is not preferable because the activated carbon is expensive.

  As the activated carbon, activated carbon having a cumulative pore volume of 0.15 to 1.0 ml / g having a pore radius of 20 mm or less is preferable from the viewpoint of the adsorption / desorption function. If the cumulative pore volume at a pore radius of 20 mm or less is less than 0.15 ml / g, the gas molecules in the system are not sufficiently adsorbed, and the impact absorbing effect may not be fully exhibited. On the other hand, if it is larger than 1.0 ml / g, the bulk density is lowered, and the adsorption / desorption function per volume is lowered. In addition, since pores having a pore radius of less than 8 mm are difficult to follow rapid pressure fluctuations due to impact, the cumulative pore volume of 8 to 20 cm is preferably 0.1 to 1.0 ml / g. More preferably, it is 3 to 0.8 ml / g.

  In the present invention, the pore radius and cumulative pore volume of the activated carbon are measured by the water vapor method shown below. In this method, the equilibrium water vapor pressure of a sulfuric acid aqueous solution having a constant concentration becomes a constant value, that is, a predetermined relationship is established between the sulfuric acid concentration of the sulfuric acid aqueous solution and the equilibrium water vapor pressure. This space is created and measured using this. Specifically, the cumulative pore volume corresponding to a predetermined pore radius is obtained based on a curve indicating the relationship between the pore diameter and the cumulative pore volume created by the following method.

  A predetermined mass of activated carbon is placed in the gas phase of an adsorption chamber containing a sulfuric acid aqueous solution having a predetermined concentration, and brought into contact with water vapor at 48 ° C. for 48 hours under the conditions of 1 atm (absolute pressure) and 30 ° C. Next, the mass of the activated carbon is measured, and the mass increase is defined as the saturated adsorption amount of water of the activated carbon at 30 ° C.

  The sulfuric acid aqueous solution adopted above has an equilibrium water vapor pressure value (P) (1 atm (absolute pressure), a value at 30 ° C.) inherent to the concentration, and the water vapor pressure has a predetermined pore radius ( r) Water vapor is adsorbed in the pores having the following radii. The predetermined pore radius is obtained based on the Kelvin equation represented by the following equation (I). And the cumulative pore volume of pores below the pore radius corresponds to the volume of water at 30 ° C. corresponding to the saturated adsorption amount of water obtained by the above measurement.

r = − [2VmγcosΦ] / [RTIn (P / P0)] (I)
Where r, Vm, γ, Φ, R, T, P, and P0 mean the following:
r: pore radius (cm)
Vm: Molecular volume of water (cm ³ /mol)=18.079 ( ³⁰ ° C.)
γ: surface tension of water (dyne / cm) = 71.15 (30 ° C.)
Φ: Contact angle between the capillary wall and water (°) = 55 °
R: Gas constant (erg / deg · mol) = 8.3143 × 107
T: Absolute temperature (K) = 303.15
P: saturated vapor pressure (mmHg) indicated by water in the pores
P0: 1 atm (absolute pressure) of water, saturated vapor pressure at 30 ° C. (mmHg) = 31.824

  As the predetermined sulfuric acid aqueous solution, eleven kinds of sulfuric acid aqueous solutions having a specific gravity of 0.025 intervals from a specific gravity of 1.05 to 1.30, a sulfuric acid aqueous solution having a specific gravity of 1.35, and a sulfuric acid having a specific gravity of 1.40. An aqueous solution (a total of 13 types of sulfuric acid aqueous solutions) is prepared, and the above measurement is performed. Thereby, in each measurement, the cumulative pore volume of pores not more than the calculated pore radius is obtained.

  By plotting the obtained cumulative pore volume against the pore radius, a cumulative pore volume curve of activated carbon can be obtained. By differentiating this, a pore distribution curve is obtained. For example, FIG. 1 shows the pore radius distribution and the cumulative pore volume with respect to the pore radius of the activated carbon obtained in Reference Examples 1 and 2 described later. In FIG. 1, a1 is a cumulative pore volume curve, b1 is a pore distribution curve, the vertical axis of a1 represents the cumulative pore volume per 1 g of activated carbon (ml / g), and the vertical axis of b1 represents a relative value. Based on the cumulative pore volume curve of the activated carbon thus obtained, the cumulative pore volume of the activated carbon having a pore radius of 20 mm or less can be determined.

As a material having flexibility for forming the sealed space, a material that can contain gas, has a strength to receive an impact force, and is excellent in easy sheet forming processability, weather resistance, and the like is used. For example, as natural materials, regenerated cellulose, acetate, triacetate, etc., as synthetic materials, polyamide resins such as nylon, polyvinyl alcohol resins such as vinylon, eval, acrylics, etc. Examples thereof include various synthetic resins that can be made into sheets, such as resins, polyacrylonitrile resins, polyolefin resins such as polyethylene and polypropylene, polyurethane resins, phenol resins, and vinyl chloride resins. Sheet materials obtained from these resins can also be used in combination. The sheet material is made into a bag and used.

A thermoplastic air barrier film that is thin, flexible, strong, and has a very low air permeability and good barrier properties is a preferred material. For example, a barrier such as Eval or nylon between polyethylene or polypropylene films. A laminate film in which a resin is interposed as an intermediate layer, a laminate of polyethylene or polypropylene film and aluminum foil, and the like can be used.

  In order to produce a bag body using the barrier film, for example, a tube made of the barrier film is formed by continuous extrusion molding, the tube material is cut into a desired length, and a necessary porous body and gas are sealed inside. The cut portion may be sealed in a sealed state by heat sealing, an adhesive or the like in a pressurized state. Since the pressure of pressurization is related to the strength of the bag body, it cannot be generally limited, but a pressure slightly higher than normal pressure is sufficient.

  Another example of the bag material for producing the bag body is a film in which a plastic film and an aluminum foil are laminated. Also in the case of obtaining a bag material using this, the necessary tube-shaped molded body can be obtained by a method of adhering end portions with a heat seal or an adhesive while making the laminated film into a tube shape in the same manner as described above. Similarly, it may be cut to a required length, sealed with a porous body, and fixed in a sealed manner by heat sealing, adhesive or the like. For example, since the air cushion formed in this way hardly transmits the internal air or the enclosed inert gas, the internal gas of the bag material can maintain good elasticity even after a long period of time.

If the amount of the porous body enclosed in the sealed space is too small, the gas adsorption / desorption performance may not be sufficiently exhibited, and the impact absorption improvement may be insufficient. Also, if too much,
Since the impact-absorbing property improving effect reaches a peak and a porous body is encapsulated in many cases, it is not preferable because it becomes a high-cost impact-absorbing material. Therefore, it is preferable to enclose or paste 2 to 15 g per 100 ml of space volume. More preferably, the amount is 4 to 10 g per 100 ml of space volume.

The gas to be sealed in the sealed space can be selected from at least one of air, oxygen, nitrogen, carbon dioxide, argon, and helium in consideration of safety, handleability, and the like.
Usually, air, nitrogen and carbon dioxide are used.

  The impact-absorbing material of the present invention can be effectively used in various application fields, particularly in applications such as vehicle airbags and shoe soles, and is a porous body in a sealed space formed of a flexible material. Contains gas and shows good recoverability even when shocked. In the present invention, the impact absorption effect was measured by the following method.

After a predetermined amount of porous material is weighed and charged into a glass or metal syringe that has a certain volume and is not affected by pressure, gas is inhaled until the scale of the syringe shows 100 ml. Close the tip of. Pressure is applied to such a sealing system, and the pressure required to achieve a predetermined volume reduction rate is measured. As shown in FIGS. 2 to 5 described later, the volume reduction rate (% The impact absorbing effect can be confirmed by taking the pressure (kg / cm ² ) on the vertical axis and comparing it with the case where no porous body is charged (blank). EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

Reference example 1
The carbide obtained by carbonizing the coconut shell was activated with a steam-containing combustion gas at 850 ° C., and the average particle size was 0
. A 35 mm granular activated carbon was obtained. The cumulative pore volume curve and pore distribution curve of this activated carbon are shown in FIG. In FIG. 1, a1 is a cumulative pore volume curve, b1 is a pore distribution curve, the vertical axis of a1 represents the cumulative pore volume per 1 g of activated carbon (ml / g), and the vertical axis of b1 represents a relative value. From FIG. 1, the cumulative pore volume of the activated carbon having a pore radius of 20 mm or less was 0.52 ml / g, and the cumulative pore volume of the pore radius of 8 to 20 cm was 0.50 ml / g. Further, the BET specific surface area was 1200 m ² / g.

12 g of this activated carbon was charged into a glass syringe, air was inhaled until the scale of the syringe showed 100 ml, and the tip of the syringe was closed. Pressure was applied to the syringe and the pressure required to achieve a predetermined volume reduction rate was measured. The results are shown in FIG. 1 is the case where no porous material was charged (blank), and 2 is the result of Reference Example 1. 2, the pressure P1 (kg / cm ² ) when the volume of the sealed space is reduced by 50% without the presence of activated carbon is 0.96, and the volume of the sealed space is 50% in 2 of FIG. The pressure P2 (kg / cm ² ) when decreased was 0.52, and (P1-P2) / W was 0.037. From this result, the effect of the present invention is clear.

Reference example 2
The same procedure as in Reference Example 1 was carried out except that the amount of activated carbon used was 6 g. The results are shown in FIG. 3 is the result of Reference Example 2. In FIG. 2, the pressure P2 (kg / cm ² ) when the volume of the sealed space was reduced by 50% was 0.68, and (P1−P2) / W was 0.047. From this result, the effect of the present invention is clear.

Reference example 3
The phenol resin fiber was carbonized to obtain a carbide, which was activated with a steam-containing combustion gas at 850 ° C. to obtain cloth-like activated carbon having an average thickness of 0.5 mm. The cumulative pore volume of the activated carbon having a pore radius of 20 mm or less was 0.71 ml / g, and the cumulative pore volume of the pore radius of 8 to 20 cm was 0.70 ml / g. Further, the BET specific surface area was 1800 m ² / g.

4 g of this phenolic resin fiber is charged into a glass syringe, and the scale of the syringe is 100 m.
Air was inhaled to the point indicated by l and the tip of the syringe was closed. Pressure was applied to the syringe and the pressure required to achieve a predetermined volume reduction rate was measured. The results are shown in FIG. 4 is the result of Reference Example 3. In 4 of FIG. 3, when the volume of the sealed space was reduced by 50%, the pressure P2 (kg / cm ² ) was 0.65, and (P1-P2) / W was 0.078. From this result, the effect of the present invention is clear.

Reference example 4
The same operation as in Reference Example 1 was conducted except that the amount of phenol resin fiber used was 2 g. The results are shown in FIG. 5 is the result of Reference Example 4. In 5 of FIG. 3, the pressure P2 (kg / cm ² ) when the volume of the sealed space was reduced by 50% was 0.78, and (P1-P2) / W was 0.09. From this result, the effect of the present invention is clear.

Reference Example 5
In the same manner as in Reference Example 1, the coconut shell was carbonized to obtain a carbide, which was activated with a steam-containing combustion gas at 860 ° C. to obtain granular activated carbon having an average particle size of 0.30 mm. The cumulative pore volume of the activated carbon having a pore radius of 20 mm or less was 0.54 ml / g, and the cumulative pore volume of the pore radius of 8 to 20 cm was 0.52 ml / g. Further, the BET specific surface area was 1300 m ² / g.

12 g of this activated carbon was charged into a glass syringe, air was inhaled until the scale of the syringe showed 100 ml, and the tip of the syringe was closed. Pressure was applied to the syringe, and the pressure required to obtain a predetermined volume reduction rate was measured (not shown). The pressure P2 for achieving a volume reduction rate of 50% was 0.50 kg / cm ² and (P1-P2) / W was 0.038. From this result, the effect of the present invention is clear.

Reference Example 6
This was carried out in the same manner as in Reference Example 1 except that 12 g of molecular sieves 13X (manufactured by Wako Pure Chemical Industries, Ltd .: cylindrical, hole diameter 10 mm, diameter 3.2 mm, length 2 to 6 mm) was used. The cumulative pore volume of Molecular Sieves 13X with a pore radius of 20 mm or less was 0.15 ml / g, and the cumulative pore volume with a pore radius of 8 to 20 cm was 0.022 ml / g. The results are shown in FIG. 6 is the result of Reference Example 6. In FIG. 5, the pressure P2 (kg / cm ² ) when the volume of the sealed space was reduced by 50% was 0.83, and (P1−P2) / W was 0.011. From this result, the effect of the present invention is clear.

Reference Example 7
The same operation as in Reference Example 6 was performed except that the amount of molecular weight 13X used was 6 g. The results are shown in FIG. 7 is the result of Reference Example 7. In FIG. 4, the pressure P2 (kg / cm ² ) when the volume of the sealed space was reduced by 50% was 0.86, and (P1−P2) / W was 0.017. From this result, the effect of the present invention is clear.

Reference Example 8
When implemented in the same manner as in Reference Example 1 using 1 g of polyurethane sponge having no gas adsorption / desorption function, (P1-P2) / W was 0.

Reference Example 9
When implemented in the same manner as in Reference Example 7 except that molecular sieve 4A was used instead of molecular sieve 13X, (P1-P2) / W was almost 0, and the effect could not be confirmed. The cumulative pore volume of Molecular Sieves 4A with a pore radius of 20 mm or less was 0.12 ml / g, and the cumulative pore volume with a pore radius of 8 to 20 cm was 0.012 ml / g.

Reference Example 10
After granulating the novolak phenol resin into a spherical shape of about 2 mm, it is carbonized at 600 ° C. to obtain a carbide, which is activated with a steam-containing combustion gas at 900 ° C., and has a BET specific surface area of 2300 m ² / g, average A phenol resin activated carbon having a thickness of 0.5 mm was obtained. The cumulative pore volume of the activated carbon having a pore radius of 20 mm or less was 0.89 ml / g, and the cumulative pore volume of the pore radius of 8 to 20 cm was 0.88 ml / g. The same procedure as in Reference Example 1 was carried out except that the amount of activated carbon used was 6 g. The pressure P2 (kg / cm ² ) when the volume of the sealed space was reduced by 50% was 0.70, and (P1−P2) / W was 0.041.

Reference Example 11
The carbide obtained by carbonizing the coconut shell was activated with a steam-containing combustion gas at 850 ° C. to obtain granular activated carbon having a BET specific surface area of 880 m ² / g and an average particle size of 0.35 mm. The cumulative pore volume of the activated carbon having a pore radius of 20 mm or less was 0.19 ml / g, and the cumulative pore volume of the pore radius of 8 to 20 cm was 0.18 ml / g. The same procedure as in Reference Example 1 was carried out except that the amount of activated carbon was changed to 10 g. The pressure P2 (kg / cm ² ) when the volume of the sealed space was reduced by 50% was 0.79, and (P1−P2) / W was 0.025. The results of the above Reference Examples 1 to 11 are collectively shown in Table 1.

Examples 1-9, Comparative Examples 1-2
80 g of each of the coconut shell activated carbons used in Reference Examples 1, 2, 5 and 11 were placed on a 1 L inner bag obtained by laminating a polyethylene film having a thickness of 70 μm and an aluminum film having a thickness of 20 μm. And 30 g of each of the phenol resin-based activated carbon used in Reference Example 10 and 100 g of each of the molecular sieves used in Reference Examples 6, 7 and 9 were filled and inflated at an internal pressure of 0.2 kg / cm ² to prepare an air cushion. (Samples 1-10). Moreover, the air cushion was produced with the polyurethane sponge 10g used by the reference example 8, and the bag body which does not prepare a porous body (samples 11-12).

  Rapid impacts by the human body were repeatedly given on these air cushions. The cushion performance of Samples 1 to 7 was extremely good, and the effect could be maintained for more than one year. Samples 8 to 10 were inferior to these, and Samples 11 to 12 were inferior in impact absorption.

Examples 10-18, Comparative Examples 3-4
1.6 g of each coconut shell activated carbon used in Reference Examples 1, 2, 5 and 11 was added to a 20-mL bag obtained by laminating a polyethylene film having a thickness of 70 μm and an aluminum film having a thickness of 20 μm, and Reference Example 3 4 and 0.6 g of each of the phenol resin-based activated carbon used in Reference Example 10 and 2 g of each of the molecular sieves used in Reference Examples 6, 7 and 9 were encapsulated and inflated with an internal pressure of 0.2 kg / cm ^2. Cushions were produced (Samples 13-22). In addition, an air cushion was produced using 0.3 g of the polyurethane sponge used in Reference Example 8 and a bag body not charged with a porous body (samples 23 to 24).

  These air cushions were loaded into shoes and repeatedly subjected to sudden impacts by the human body. The cushion performance of Samples 13 to 19 was extremely good, and the effect could be maintained for more than one year. Samples 20-22 were inferior to these, and samples 23-24 were inferior in shock absorption.

  According to the shock absorbing material of the present invention, the thickness and volume of the shock absorbing material can be reduced, and further performance enhancement can be realized. The present invention can be preferably applied to the use.

1 No preparation of porous material (blank)
2 Use of 12 g of coconut shell activated carbon 3 Use of 6 g of coconut shell activated carbon 4 Use of 4 g of phenol resin activated carbon 5 Use of 2 g of phenol resin activated carbon 6 Use of molecular bus 13X12 g 7 Use of molecular bush 13 X 6 g

Claims (4)

An impact-absorbing material formed by enclosing a porous body having a gas adsorption / desorption function and a gas in a bag made of a flexible material to form a sealed space. The pressure when reducing the volume of the sealed space by 50% with the porous body W (g) present is P2 (kg / cm ² ), and the volume of the sealed space is reduced by 50% without the porous body. The shock absorbing material according to claim 1, wherein (P1-P2) / W is 0.01 (kg / cm ² · g) or more, where P1 (kg / cm ² ) is the pressure at the time. The impact absorbing material according to claim 1 or 2, wherein the porous body is activated carbon. 4. The impact absorbing material according to claim 3, wherein a cumulative pore volume of the activated carbon having a pore radius of 20 mm or less is 0.15 to 1.0 ml / g.