JPH0415694B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Technical Field The present invention relates to a heat storage body for use in cold pillows, hot compresses, and the like.

b. Prior Art and its Problems Conventionally, cooling bodies of the type that are frozen in a freezer or the like have been provided as cooling pillows. Usually, this type of cooling body is made by filling the inside of the bag with a heat storage material whose main ingredient is polyvinyl alcohol. It is frozen, which has the disadvantage of causing discomfort to users such as sick people.

In addition, cooling bodies that have improved the above-mentioned drawbacks have been proposed, and some of them have been put into practical use. For example, antifreeze is placed near the outer periphery of the bag, urethane foam impregnated with antifreeze is placed near the outer periphery of the bag, W/O emulsion is used as a heat storage material, O/W These include those that use mold emulsion as a heat storage material. However, in the above-mentioned types of cooling bodies, the antifreeze does not solidify, but other parts solidify, so the feeling of use cannot be sufficiently improved, and since the antifreeze does not freeze, the latent heat accompanying thawing cannot be utilized. has a small heat capacity. The cooling body is relatively flexible even at low temperatures, but on the other hand, it has elasticity even at low temperatures and does not easily undergo plastic deformation, so when used as a pillow, it does not feel good when used. In addition, the cooling body solidified in a few hours in a freezer (at a temperature of about -20°C), causing problems such as a poor feeling of use.

c. Purpose of the Invention The present invention has been made in view of the above circumstances, and is capable of being deformed without hardening even when frozen.
It is an object of the present invention to provide a heat storage body that makes good contact with objects to be cooled or heated and has a good feeling of use.

d.Structure of the Invention In order to achieve the above object, the present invention comprises a heat storage body filled with microcapsules whose core material is made of a water-retentive material in a gel state and whose wall material is made of fine powder inside a bag. .

e Specific Structure of the Invention The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is a diagram showing an embodiment in which the present invention is applied to a cooling pillow. Cold pillow 1 shown in this figure
The bag body 2 is filled with microcapsules 3 as a heat storage material.

The bag body 2 is formed into a bag shape using a synthetic resin (e.g., polyethylene terephthalate, nylon, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, etc.) that maintains sufficient flexibility even when frozen. It is.

Further, as shown in FIG. 2, the microcapsule 3 has a core material 4 made of a granular water-retaining material containing water, and its surface is covered with a wall material 5. Examples of water-retentive substances include CMC
(carboxymethylcellulose), poval, agar powder, gelatin, mannan, calcium alginate, carrageenan, carboxyvinyl polymer, polyvinyl alcohol, gum arabic,
Water-soluble polymers and water-absorbing polymers such as PVC can be suitably used. This water-retentive material is used as a core material in a gel state using water as a dispersion medium.

Further, as the wall material, fine powder such as silica fine powder, alumina fine powder, carbon fine powder, etc. is used.

The particle size of the microcapsules 3 can be appropriately determined depending on the intended use, but for example, when used in a cooling pillow, it is preferably about 1 to 1000 μm. Further, the ratio between the particle size of the core material 4 and the particle size of the wall material 5 is preferably such that the particle size of the core material is 1 and the particle size of the wall material is about 1/10 or less. In addition, the structure of the covering wall of the microcapsules does not need to be a dense structure, and unnecessary adhesion between microcapsules does not occur, and even when the core material is in a frozen state or a thawed state, It is sufficient to maintain a fluid granular state.

Next, a method for producing microcapsules used in the present invention will be explained. In general, it is difficult to microcapsule gel-like substances or colloidal substances using water as a dispersion medium with a good yield, but the present inventors have developed a method using the following manufacturing method that allows for a simple operation with a good yield and at a low cost. microcapsules such as gel-like substances are obtained by

First, prepare a gel (or solution, colloid, etc.) of the water-retaining substance with a predetermined water content, and freeze it at a temperature of about -20°C using liquid nitrogen dry ice or the cold heat of a refrigerator. Then, in this state, it is powdered to a predetermined particle size. Next, wall material powder adjusted to a predetermined particle size is added to the core material, mixed and stirred at a temperature below the freezing temperature of the core material, and microencapsulated. In this case, it is preferable to use a high-speed stirrer with a cutter equipped with a cooling means such as a liquid nitrogen cooling jacket for stirring, and the stirring conditions are as follows: stirring speed is 5000 to 30000 rpm and stirring time is several seconds to 10 minutes. In particular, when this type of stirrer is used, the core material can also be freeze-pulverized within this device, which is advantageous in terms of the process. In addition, a ball mill, an attritor, etc. can also be used for mixing and stirring.

In the microcapsules obtained as described above, the core material is covered with a wall material, and the microcapsules become a powder or granule with smooth fluidity even at temperatures below the freezing temperature of the core material and at temperatures above room temperature.

f. Specific functions and effects of the invention However, the cooling pillow 1 filled with microcapsules as described above has smooth fluidity even in a frozen state because the microcapsules 3 inside the bag body 2 have smooth fluidity. 1 surface is easily deformed according to the shape of the object to be cooled, and therefore feels good in use. In addition, by appropriately selecting the particle size of the microcapsules,
It can be made into a cooling pillow that has the feel of buckwheat hulls.

g. Another embodiment of the invention FIGS. 3 and 4 show another embodiment of the invention.

The cooling pillow 6 shown in FIG. 3 is constructed by arranging a heat storage material 7 at the center inside the bag body 2 and filling the microcapsules 3 so as to surround the heat storage material 7. As the heat storage material 7, for example, a bag member 9 made of the same synthetic resin as the bag body 2 filled with a gel-like substance 8 similar to the core material of the microcapsules 3 can be used.

According to such a cooling pillow 6, not only can the feeling of use be as comfortable as that of the cooling pillow shown in FIG. I can do it.

Further, the cooling pillow 10 shown in FIG. 4 includes a heat storage material 11 connected to the external bag body 2 at both longitudinal ends of the pillow in place of the heat storage material 7 shown in FIG. According to such a cooling pillow 10, since the position of the heat storage material 11 inside the bag body 2 is stabilized, there is also an advantage that it is easy to handle.

In addition, in the above-mentioned examples, examples in which the present invention is applied to cold pillows have been explained, but the present invention is not limited to these examples, and can be applied to cold clothes, cold hats, heat storage bodies for hot compresses, etc. It can be used as a variety of heat storage and cold storage heat sources.

h Manufacturing Example Manufacturing Example 1 Using a water-absorbing polymer (starch, water content 70%) as the core material of the microcapsules, and using hydrophobic silica fine powder (average particle size 16 x 10 ^-3 μm) as the wall material, each Microcapsules with an average particle size of 500 μm were prepared at a weight ratio of 100:5. This microcapsule was filled into a bag made of nylon to produce a cold pillow having the shape shown in FIG. The filling amount of microcapsules is 800g.

After freezing this cold pillow in a freezer, it was taken out and its cold retention ability was measured at an ambient temperature of 25°C. As shown in Figure 5, it was possible to maintain a temperature around 0°C for about 4 hours.

The cold retaining power of the cold pillow changes depending on the ratio of the core material to the wall material, and as the ratio of the wall material increases, the cold retaining power decreases. This relationship was confirmed as follows. In other words, the ratio of the amount of core material to wall material is 100:
Microcapsules were prepared with different ratios of 20 and 100:5, 800 g of each microcapsule was used to make cooling pillows, and the cold retention power was measured under the same conditions as above. The results are shown in FIG. In this figure, curve A shows the measurement results when the ratio of core material to wall material was filled with 100:20, curve B with 100:5, and curve C with the same weight of water for comparison. When using microcapsules of the same weight in this way,
The higher the proportion of the core substance, the higher the cold retention ability, but there is a limit to the stability of the microcapsules even if the proportion of the wall substance is reduced. Therefore, if it is necessary to increase the cold storage capacity, please refer to Figures 3 and 4.
A cooling pillow having the structure shown in the figure may be used to increase the proportion of heat storage material.

Production Example 2 Microcapsules were prepared using a gel of an aqueous solution of PVA (concentration 4%) as the core material of the microcapsules and the same hydrophobic Aerosil as in Production Example 1 as the wall material. This microcapsule was used as an internal filler for a chiller and a cap to produce a chiller and a hat for keeping cool. When these were placed in a -20°C freezer for 24 hours, they did not lose their flexibility at all and felt good when worn on the body. In addition, when I wore the above-mentioned cold-retaining tip and cold-retaining hat and used it for work under the scorching sun or around fire, I found that it remained flexible even in frozen conditions, making it easy to work, and it also felt cool and comfortable. I was able to do the work.

i Effects of the Invention As explained in detail above, the heat storage body of the present invention is formed by filling the inside of the bag with microcapsules in which the core substance is made of a water-retentive substance in a gel state and the wall substance is made of fine powder. Even when the core substance is frozen or heated, the fluidity of the microcapsules can be maintained without causing aggregation between the particles of the microcapsules, so the heat storage body can be freely deformed and can be used for cooling or heating. Since it is possible to have a good contact state with the object to be kept warm and a large contact area can be obtained, it is possible to exhibit excellent cold or heat keeping ability. Furthermore, due to the fluidity of the microcapsules, the heat storage body does not harden and is easily plastically deformed as a whole, resulting in a good feeling of use. Furthermore,
As the microcapsules used as a heat storage material are made of a gel-state water-retaining material as the core material and a fine powder as the wall material, the gel-state water-retaining material with a large amount of heat storage can be easily and reliably stored. , and can be microencapsulated at low cost, providing a heat storage body with excellent heat retention and cold retention properties and a good feeling of use at a low price.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an example of the structure of a microcapsule used in the present invention, and FIGS. 5 is a partially cross-sectional front view showing another embodiment of the present invention, FIG. 5 is a graph showing the measurement results of the cold retention power in Production Example 1, and FIG. 6 is a graph showing the core material of the microcapsule in Production Example 1. It is a graph showing the measurement results of the cold retention power when the quantity ratio with the wall material is changed. 1...Cold pillow (heat storage body), 2...Bag body, 3...
Microcapsule, 4... core material, 5... wall material, 6... cold pillow, 7... heat storage body, 10... cold pillow, 11... heat storage material.

Claims (1)

[Scope of Claims] 1. A heat storage body comprising a bag filled with microcapsules whose core substance is made of a water-retentive substance in a gel state and whose wall substance is made of fine powder. 2. The heat storage body according to claim 1, wherein the bag body includes a heat storage material therein, and the microcapsules are filled so as to surround the heat storage material.