JPH02208388A - Cooling medium composition - Google Patents

Abstract

PURPOSE:To form a cooling medium composition which can maintain its cooling effect for a long time and can be stored and used as a handy cooling agent without any obstacle even in summer by combining a powdery substance undergoing endothermic dissolution with a water-insoluble metallic alginate in hydrogel form. CONSTITUTION:The title composition is formed from a powdery substance undergoing endothermic dissolution, which absorbs heat when dissolved, and a water-insoluble metallic alginate in hydrogel form. When these ingredients are mixed, water oozes from the metallic alginate in gel form to dissolve the substance undergoing endothermic dissolution so that temperature is lowered. As the substance undergoing endothermic dissolution, a powder comprising a mixture of ammonium nitrate with urea is preferably used in particular since it gives a temperature as low as about -6 to -8 deg.C. The metallic alginate in hydrogel form can be obtained by mixing an aqueous solution of sodium alginate with an aqueous solution of, e.g. calcium chloride or magnesium chloride. It is desirable to incorporate fine pieces or microspheres of a water- absorptive polymer containing water, or a thickening agent into said metallic alginate in hydrogel form to enhance water retentivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cooling composition using a substance that absorbs heat when dissolved, for use in cooling foods and beverages, regulating body temperature, and the like.

[Conventional technology] Traditionally, food and drinks have been kept cool while on vacation, cooled the head of a sick person with a fever at home or in a hospital, or used to cool the head of a patient with a fever while fishing, attending sports, or at a construction site in the summer. A simple coolant is used to reduce the heat.

This simple coolant uses a dissolved endothermic substance such as thorium nitrate or ammonium nitrate that absorbs heat when dissolved, and utilizes the dissolution endothermic reaction when this dissolved endothermic substance is mixed with water.

For example, simple packaged refrigerants are already commercially available from Johnson Company, USA, etc. for medical or recreational use. These simple coolants are made by sealing a dissolved endothermic substance powder and water separated by a water-impermeable inner bag or partition wall such as a plastic film in a thick, strong, water-impermeable outer bag. During use, water and dissolved endothermic substances are mixed by tearing the inner bag or partition wall, and the temperature of the entire outer bag is lowered to cool the surrounding area.

Such conventional simple coolants are small and convenient to carry, and have the advantage of being able to be taken out and used at any time; however, because water is used to dissolve the dissolved cooling substance, the dissolved endothermic substance starts to dissolve rapidly. Moreover, dissolution ends early.

For this reason, the lowest temperature is reached in a short time, but the time to return to room temperature is extremely short, and the cooling effect is usually 15 to 20 minutes.
The drawback was that it only lasted for minutes.

Therefore, in order to maintain the cooling effect for a long time, it has been considered to slow down the dissolution rate of dissolved endothermic substances, such as using crystallized water of inorganic salts instead of water, and mixing thickeners such as carboxymethyl cellulose (CMC) at the same time. Several methods have been proposed.

However, inorganic salts such as inorganic sodium salts and inorganic potassium salts that have water of crystallization have low melting points; for example, the melting point of sodium sulfate decahydrate, which is considered the most effective, is 32.3.
It is °C. For this reason, during the summer when coolants are frequently used, non-Ia mounds may partially or completely melt and become ice-like during storage, making them ineffective in slowing down the dissolution rate of endothermic substances. There was a big drawback. Also, the method of adding a thickener only increases the viscosity of the water;
It was not possible to delay the supply of water to the dissolved endothermic substance, and the effect of sustaining the cooling time was not sufficient.

[Problems to be Solved by the Invention] In view of the conventional circumstances, the present invention provides a cooling composition that can maintain a cooling effect for a long time and can be stored and used as a simple cooling agent even in summer without any problems. The purpose is to provide

[Means for Solving the Problem] In order to achieve the above object, the cooling composition of the present invention has the following features:
It consists of a powdery dissolving endothermic substance that absorbs heat when melted and a water-insoluble gelled alginate metal salt, and by mixing the two, water leaches from the gelled alginate metal salt and the dissolving endothermic substance absorbs heat when dissolved. It is characterized by melting substances and lowering the temperature.

Dissolved endothermic substances are substances that absorb heat when dissolved in water, and are already used in simple coolants as described above. Examples include ammonium nitrate, sodium nitrate, sodium thiosulfate, ammonium chloride, calcium chloride hexahydrate, urea, etc. One or two of these substances
More than one species can be used. In particular, a mixed powder of ammonium nitrate and urea is preferred since it can provide a low temperature of about -6 to -8°C.

The water-containing gelled metal alginate used for supplying water to the dissolved endothermic substance in the present invention can be produced by mixing an aqueous solution of sodium alginate with an aqueous solution of calcium chloride, maleic chloride, etc., and contains water inside. It is a water-insoluble gel-like substance that is dispersed and contained. Although it is not necessary to particularly control the amount of water contained in the gelled metal alginate, good results can usually be obtained by using an aqueous sodium alginate solution having a concentration of about 1 to 3% by weight.

There is no particular restriction on the shape of the gelled alginate metal salt, but in order to obtain a good mixing state with the dissolved endothermic substance, it is preferably in the shape of small spheres or strips. For example, if an aqueous solution of sodium alginate is added dropwise to an aqueous solution of calcium chloride or the like when the two are mixed together, it will coagulate into small spheres, and by controlling the rate of addition, particles of an appropriate size (approximately 1 to 5 InI11) can be obtained. Further, it is also possible to cut or grind the solidified lumps, rods, or strings to make them finer.

Water-containing gelled metal alginate tends to gradually liberate water when left unattended, so in order to improve water retention, water-absorbing particles or microspheres smaller than the gelled metal alginate to be generated are used. It is preferable to mix the polymer into an aqueous sodium alginate solution and coagulate it, so that the water-absorbing polymer that has absorbed water is dispersed and contained in the gelled metal alginate. or,
A similar effect can be obtained by including a thickener such as CMC in the gelled alginate metal salt.

The above-mentioned water-absorbing polymer is a polymer having a three-dimensional network structure that absorbs a large amount of water by itself, swells, and turns the entire body into a gel.Using this property, This is a well-known material that has already been applied to cold storage materials, sanitary products, disposable diapers, etc. Water-absorbing polymers can be classified by raw material into starch-based, cellulose-based, and synthetic polymer-based, and in terms of form, they can be classified into powder, fiber, granule, and sheet. Specific examples include ``Sumikagel'' by Sumima Kagaku Kogyo Co., Ltd. and ``Aqua Gel'' by Eslen Kako Co., Ltd.
U Ace”, Sanyo Chemical Industries Co., Ltd.’s “Sunwet”,
“Aqua Keep” by Tetsu Seikagaku Co., Ltd., “Aqua Keep” by Steel Chemical Co., Ltd.,
Co., Ltd.'s Chikupolymer AQJ, and many other types are industrially produced and commercially available.

Note that the filtrate that is hydrated in the gelled alginate metal salt and the water that is absorbed by the water-absorbing polymer may be ordinary tap water, but sodium sulfate, sodium acetate, sodium thiosulfate,
It may be an aqueous solution of inorganic salts such as potassium sulfate and ammonium sulfate, and the present invention is used to include this.

Several types of means are already known for storing the powder of the dissolved endothermic substance and the gelled alginate metal salt separately from each other so that they can be mixed during use, and when the composition of the present invention is also used as a simple coolant, these methods can be used. The following methods may be adopted. For example, as mentioned above, both substances are sealed in a water-impermeable outer bag made of plastic or the like, separated by a water-impermeable inner bag or partition, and when used, the outer bag is rubbed by hand to break the inner bag or partition. For example, a method of mixing both substances.

In addition, when storing the powder of the dissolved endothermic substance and the gelled alginate metal salt separately, if the two-component pigment that develops color when mixed is stored separately at the same time, the color will develop as soon as they are mixed and cooling begins. The product value can be increased by giving a refreshing feeling in terms of color and so on.

[Function] The gelled alginate metal salt produced as described above retains water in its original state, and gradually liberates water only when it comes into contact with a dissolved endothermic substance. Therefore, the rate at which the dissolved endothermic substance dissolves in the water liberated from the gelled alginate metal salt becomes extremely slow, and the cooling effect due to dissolution is maintained for a long time. In particular, when fine pieces or microspheres of water-containing water-absorbing polymer are dispersed and contained in the gelled alginate metal salt, the cooling effect can be maintained for a longer period of time.

Moreover, when inorganic salts are dissolved in advance in the water contained in the gelled alginate metal salt or water-absorbing polymer, the higher the concentration of the inorganic salts, the slower the rate at which the dissolved endothermic substances are dissolved in the liberated inorganic salt aqueous solution. The cooling effect can be maintained for a longer period of time.

The ratio of the water-containing gelled alginate metal salt to the dissolved endothermic substance is arbitrary, but it is usually preferred that the weight ratio is 1 to 1 for the former. Even a small amount of the water-absorbing polymer contained in the gelled metal alginate has the effect of improving water retention, but the former is usually preferably about 50% by weight. In addition, the gelled alginate metal salt containing water and the water-absorbing polymer that has absorbed water do not melt or release the absorbed water at summer temperatures, and can be used without any problems.

Furthermore, if a water-absorbing polymer (preferably in the form of powder or fibers) that does not absorb water is mixed with the powder of the dissolved endothermic substance, the cooling effect will be further enhanced, although the minimum temperature for cooling will be slightly higher than when no water is mixed. It can last for a long time, and furthermore, it can absorb the solution after the dissolved endothermic substance has dissolved and keep the entire solution in a solid state, so that a preferable feeling of use as a coolant can be obtained.

[Example] A finely ground "Aqua-U Ace" (gel-like water-absorbing polymer manufactured by Eslen Kako Co., Ltd.) was divided into an aqueous solution (2.5% by weight) of sodium alginate "Shikoban". After adding and mixing 40% by weight, this was added dropwise to an aqueous calcium chloride solution to coagulate into small spheres with a diameter of 2H.

Add 150 g of the resulting water-containing gelled calcium alginate pellets to 250 g of mixed powder of sodium nitrate and urea (sodium nitrate:urea = 2:1 in weight ratio), mix well, and adjust the temperature of the mixture over the elapsed time. The results of each measurement are shown in Table 1. Note that the room temperature during the experiment was 23°C.

Table 1 Mixing After 5 minutes After 10 minutes After 20 minutes After 30 minutes 23℃
0°C-6°C-6°C-5, 56C after 40 minutes 5
After 0 minutes After 60 minutes After 70 minutes After 80 minutes 55℃ -5
℃ -4°C-4,5°G -3,5°C After 90 minutes After 100 minutes After 110 minutes After 150 minutes 2.5°C-1
0C! OoC 15°C From the above results, it can be seen that the cooling effect appeared within 5 minutes after mixing, the negative temperature could be maintained for about 2 hours, and the cooling effect continued for more than about 2 hours in total.

Shiran Group: A hydrated gelled calcium salt of alginate was produced in the same manner as in Example 1 except that no water-absorbing polymer was added, and 150 g of the resulting hydrated gelled calcium salt were mixed with sodium nitrate and urea. The mixture was added to 300 g of mixed powder (weight ratio is the same as in Example 1) and mixed well, and the temperature was measured in the same manner as in Example 1. The results are shown in Table 2. The room temperature during the experiment was 20°C.

In addition, in the above experiment, mixed powder of sodium nitrate and urea 3
00g, "Aqua Keep 10SH" does not absorb water
(Powdered water-absorbing polymer manufactured by Seitetsu Kagaku Kogyo Co., Ltd.)
5g were premixed.

Table 2 Mixing After 5 minutes After 10 minutes After 20 minutes After 30 minutes 20℃
-1℃ -5℃ -6℃ -6℃After 40 minutes After 50 minutes After 60 minutes After 70 minutes After 80 minutes 5°O-4℃ -3
℃ -2°O-16C9O minutes after 100 minutes 130
Minutes later 0°C 5°0 15°C Water-containing gelled calcium alginate gradually releases water when left to stand, and most of the released water before mixing is mixed with the mixed powder of sodium nitrate and urea. Although it was absorbed by the water-absorbing polyester, the cooling rate was slightly faster than in Example 1 because some of the sodium nitrate and urea were dissolved. Further, the water in which sodium nitrate and urea were dissolved in M# from the gelled calcium alginate salt after mixing was also sequentially absorbed by the water-absorbing polymer, and no water remained as it was.

[Effects of the Invention] According to the present invention, it is possible to provide a cooling composition that can maintain a cooling effect for a long time and can be stored and used without any trouble even in summer.

This cooling composition can be used as a variety of cooling agents, and is particularly suitable for use as a simple, portable cooling agent.

No2

Claims (2)

[Claims] (1) It consists of a powdery dissolved endothermic substance that absorbs heat when dissolved, and a water-insoluble gelled metal alginate, and by mixing the two, water leaches from the gelled metal salt. A cooling composition characterized by dissolving the endothermic substance and lowering the temperature. (2) The cooling composition according to claim (1), wherein the gelled alginate metal salt contains minute pieces or microspheres of water-containing water-absorbing polymer, or a thickener. .