JPH0913021A - Cooling agent - Google Patents

Abstract

PURPOSE: To obtain a cooling agent which is highly effective in a high- temperature atmosphere, does not deteriorate during storage, can form crystals not changed in size when recrystallized and is less injurious to the skin by mixing specified compounds with inorganic foamed particles. CONSTITUTION: A mixture (A) of 100 pts.wt. mixture of ammonium nitrate with urea in a weight ratio of 0.5-10.0 with 1-20 pts.wt. pumiceous sand balloons as inorganic foamed particles is sealed in a polyethylene pouch, this pouch together with a mixture of 100 pts.wt. sodium sulfate decahydrate (B) with 1-20 pts.wt. pumiceous sand balloons as inorganic foamed particles are placed in an outer aluminum laminate bag and sealed therein. The weight ratio of the component A to the component B should be 1.0-2.0. When a sample of the cooling agent is left standing in a thermostat at say 40 deg.C for 24hr, the left standing in a thermostat at 0 deg.C for 24hr, and the inside pouch is ruptured by externally applying a shock thereto at an atmosphere temperature of 30 deg.C, the lowest temperature is about -3 to 5 deg.C, and the duration of cooling to 10 deg.C or below is about 40min.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to coolants and more particularly to waterless coolants.

[0002]

2. Description of the Related Art Conventionally, as a simple cooling material that does not require external energy such as electric power, a cold storage agent that uses a substance having a large heat storage capacity and a coolant that uses heat absorption that occurs when two or more substances are mixed. Are known, and they are becoming popular as a simple cooling agent for the human body and foods. The former regenerator has the drawback that it must be cooled in advance in a refrigerator or freezer before it is used, which is inconvenient and cannot be used immediately. On the other hand, the latter coolant has an advantage that a cooling effect is obtained only by mixing at least two kinds of substances without requiring a prior cooling operation.

[0003]

As such a cooling agent, inorganic salts such as inorganic ammonium salts and alkali metal salts, or a mixture thereof with urea and water in combination, or an inorganic salt and crystal water are used. The combination with the salt hydrates that it has is well known. Among them, the one using water has an advantage that the rise of cooling is quick, but since water is used, the blending amount of the main component of the cooling agent becomes small, and the cooling capacity is reduced. On the other hand, a salt hydrate containing water of crystallization has a relatively low cooling effect, and improvement is desired, and none of them is practically satisfactory.

As a countermeasure for this problem, a method using strontium hydroxide octahydrate as a salt hydrate having water of crystallization has been disclosed (Japanese Patent Laid-Open No. 5-78651). This method improves the minimum temperature obtained, but does not satisfy the low temperature maintenance time. In addition, the pH is strongly alkaline, and if it adheres to the skin, it will be greatly damaged when it enters the eye, and it is necessary to improve the safety. Further, as a method considering safety, a method using sodium metasilicate nonahydrate, sodium sulfate decahydrate, etc. is known. In particular, sodium sulfate decahydrate has been attracting attention due to low temperature maintenance time and the like.

However, sodium sulfate decahydrate has a low transition temperature to an anhydrate, which is as low as 32.4 ° C., and above this temperature, it is dissolved by the water of crystallization that is liberated, and again falls below this transition temperature. In the case of recrystallization, unlike the crystal shape before recrystallization and dissolution, generally it becomes a large crystal,
Mixability with other components is significantly reduced. For this reason, sodium sulfate decahydrate has serious problems in storability and workability, which is an obstacle to practical use.

Further, as a mixture of inorganic salts such as an inorganic ammonium salt and an alkali metal salt used in combination with sodium sulfate decahydrate or a mixture thereof with urea, a mixture of ammonium nitrate and urea is used because of its cooling performance. Has been done. Ammonium nitrate has a melting point of 1
65 ° C, urea is as high as 132.5 ° C, which is not a problem for practical use, but when the mixture, for example, 1: 1 by weight, the melting point decreases to about 34 ° C, and it has the same shelf stability and workability as sodium sulfate decahydrate There is a big problem in sex. Particularly, in the case of a coolant that uses water of crystallization, it is a practical obstacle.

[0007]

In order to solve this problem, the inventors of the present invention have a high cooling effect even when used in a high temperature atmosphere of 30 ° C. or higher, and crystallize even if the atmospheric temperature rises to 40 ° C. or higher during storage. As a result of intensive research to obtain a coolant that does not show deterioration in storage stability due to the dissolution of the product, does not change in crystal size during recrystallization, and has little damage even if it adheres to the skin, ammonium nitrate The inventors have found that an excellent cooling agent can be obtained by mixing inorganic foam-containing particles with a mixture of water and urea and sodium sulfate decahydrate, and completed the present invention.

That is, the present invention relates to a coolant comprising a mixture of ammonium nitrate and urea and sodium sulfate decahydrate mixed with inorganic foam particles.

The present invention will be described in more detail. Ammonium nitrate, urea and sodium sulfate used in the present invention 10
The hydrate may be industrially used or generally commercially available.

In the present invention, the mixing ratio of ammonium nitrate and urea is preferably 0.5 to 10.0 by weight. Also,
A mixture of ammonium nitrate and urea and sodium sulfate 10
The weight ratio of the hydrate is preferably 1.0 to 2.0.

The inorganic foamed particles used in the present invention are preferably Shirasu balloons obtained by heat-expanding shirasu, and porous perlite, vermiculite, fly ash, etc. obtained by heat-expanding pearlite, obsidian, and hirucite. , Shirasu balloon is particularly preferable.

The shirasu balloon is made of fine glass material obtained by subjecting the fine volcanic glass particles contained in the shirasu to heat treatment at about 1000 ° C. for a short time using a rotary kiln, a shaft kiln, a fluidized bed type kiln, or the like. It is a hollow body. Shirasu balloon is an inorganic bubble-containing particle that has a very low bulk specific gravity, hardly affects the weight of the product, and is highly safe.

The amount of the inorganic foam-containing particles added is 1 to 20 parts by weight of the inorganic foam-containing particles, and 100 parts of sodium sulfate decahydrate to 100 parts by weight of the mixture of ammonium nitrate and urea.
The amount of the inorganic foam-containing particles is preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight, based on parts by weight.

If the amount of the inorganic foam-containing particles added is less than 1 part by weight, the powder state cannot be maintained when the mixture of ammonium nitrate and urea and sodium sulfate decahydrate is dissolved, and the crystal shape is recrystallized. In contrast, the miscibility with other components is significantly reduced. In addition, the addition amount of the inorganic foam-containing particles is 2
If it exceeds 0 part by weight, not only the fluidity is lowered, but also the cooling effect is lowered, which is not preferable.

Although such an effect due to the addition of the inorganic foam-containing particles is not clear, the dissolved crystals are retained on the surface of the inorganic foam-containing particles, voids and the like and behave like powders, and also during recrystallization. It is presumed that since the crystals are formed on the surface of the inorganic foam-containing particles and in the voids, the behavior is suitable. Also,
In the case of a mixture of ammonium nitrate and urea, it is presumed that the contact with each of them is prevented by the inorganic foam-containing particles and the lowering of the melting point is prevented.

The coolant of the present invention is prepared by storing a mixture of ammonium nitrate and urea and a mixture of sodium sulfate decahydrate and inorganic foam-containing particles in a separate container, and taking out and mixing them at the time of use. Ordinarily, it is usually stored in a bag or container having a separating means such as a small bag or a partition that can be easily removed and stored separately as a portable coolant. When the cooling agent is used, the partition means is removed by applying pressure, impact, etc., so that the contents are mixed, cooling is started, and each cooling purpose is provided. As described above, it is easily inferred that the bag and the container are damaged due to the pressure and impact applied during use, and the contents are leaked, so that safety is required. Although the pH of the cooling agent of the present invention varies depending on the respective compounding ratios, it is generally 6 to 8, and the safety thereof is high, and the cooling agent of the present invention is also suitable.

[0017]

EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited thereto. In the following, all parts and% are parts by weight and% by weight. Example 1 A mixture of 30 parts of ammonium nitrate (manufactured by Ube Industries, Ltd.) and 30 parts of urea (manufactured by Mitsui Toatsu Kagaku Co., Ltd.) and 1.2 parts of Shirasu balloon (DSRF manufactured by Daiken Kogyo Co., Ltd.) as inorganic foam-containing particles was polyethylene. Enclosed in a small pouch made of sodium sulfate, and 50 parts of sodium sulfate decahydrate (manufactured by Koei Chemical Co., Ltd.) and Shirasu balloon as inorganic foam particles (DSRF manufactured by Daiken Kogyo Co., Ltd.)
A coolant sample was prepared by encasing with one part of the mixture in an aluminum laminated outer bag and sealing. This coolant sample was left in a constant temperature bath of 40 ° C. for 24 hours and then in a constant temperature bath of 0 ° C. for 24 hours. This is 30
After leaving it in a constant temperature bath for 24 hours, at the ambient temperature of 30 ° C., an external impact is applied to this coolant to destroy the polyethylene small bag, and then a thermocouple thermometer is attached to the surface of the outer bag. The minimum temperature and the cooling duration at 10 ° C. or lower were measured. As a result, the minimum temperature was −4.8 ° C. and the cooling duration was 36 minutes, and there was no problem in practical use during storage. The pH of the produced slurry was 6.6.

Example 2 Shirasu balloons were used as the inorganic foam-containing particles,
The same procedure as in Example 1 was performed except that the addition amount was changed to 5 parts. As a result, the lowest temperature was −4.1 ° C. and the cooling duration was 40 minutes, and there was no problem in practical use during storage. The pH of the produced slurry was 6.6.

Example 3 Shirasu balloons were used as the inorganic foam-containing particles,
The same procedure as in Example 1 was carried out except that the addition amount was changed to 10 parts. As a result, the minimum temperature was −3.5 ° C. and the cooling duration was 30 minutes, and there was no problem in practical use during storage. The pH of the produced slurry was 6.6.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the silas balloon was omitted from Example 1. As a result, the mixture of ammonium nitrate and urea and the bag contents of sodium sulfate decahydrate were solidified, but after the impact was applied from the outside to destroy the polyethylene sachet inside, the same as in Example 1. It was measured. As a result, it was found that the lowest temperature was −5.0 ° C. and the cooling duration was 42 minutes, but it solidified during storage, which was a problem in practical use. The pH of the produced slurry was 6.6.

Comparative Example 2 A mixture of 30 parts of water and 60 parts of strontium hydroxide octahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was enclosed in a polyethylene pouch, and this pouch was ammonium nitrate (manufactured by Ube Industries Ltd.) 60.
A cooling agent sample was prepared by storing the cooling agent sample in an aluminum laminated outer bag together with the parts and sealing. This sample was left in a constant temperature bath of 40 ° C. for 24 hours and then in a constant temperature bath of 0 ° C. for 24 hours. Add this to a 24 ° C constant temperature bath.
After allowing to stand for a period of time, an external impact was applied to this coolant at an ambient temperature of 30 ° C. to destroy the polyethylene pouch inside, and the same measurement as in Example 1 was performed. As a result, the lowest temperature was −4.2 ° C. and the cooling duration was 16 minutes, and there was no problem in practical use during storage, but the cooling duration was 16 minutes, which was very short compared to the examples. The pH of the produced slurry was 12.6.

[0022]

EFFECTS OF THE INVENTION The cooling agent of the present invention has a high melting point and a high transition temperature to an anhydrate by adding a mixture of ammonium nitrate and urea, sodium sulfate decahydrate and inorganic foam-containing particles. The present invention provides a coolant having temperature stability and high safety and a higher cooling effect. That is, although the comparative example of the present invention has the effects of the minimum temperature and the cooling duration, the mixture of ammonium nitrate and urea and the bag contents of sodium sulfate decahydrate solidify during storage, which is a problem in practical use. I knew that.
On the other hand, the examples do not solidify during storage and satisfy all other properties.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Inoue 7-1, 1-1 Hikoshimasako-cho, Shimonoseki, Yamaguchi Prefecture Mitsui Toatsu Chemical Co., Ltd.

Claims (4)

[Claims] 1. A coolant comprising a mixture of ammonium nitrate and urea and sodium sulfate decahydrate mixed with inorganic foam particles. 2. A mixture 10 of ammonium nitrate and urea.
The cooling according to claim 1, wherein 1 to 20 parts by weight of inorganic foam-containing particles is contained in 0 part by weight, and 1 to 20 parts by weight of inorganic foam-containing particles is contained in 100 parts by weight of sodium sulfate decahydrate. Agent. 3. The weight ratio of ammonium nitrate and urea is 0.5 to 10.0, and the weight ratio of the mixture of ammonium nitrate and urea and sodium sulfate decahydrate is 1.0.
The cooling agent according to claim 1, which is ˜2.0. 4. The cooling agent according to claim 1, wherein the inorganic foam-containing particles are shirasu balloons.