JP2000154379A - Freezing agent, thermostatic chiller and quick chiller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a freezing agent producible in common freezers and capable of retaining a peculiar freezing temperature for a long period of time by constituting itself of a material affording a thermostatic iced form capable of continuously retaining a specific freezing temperature. SOLUTION: This freezing agent is obtained by constituting itself of a material affording a thermostatic iced form capable of continuously retaining a freezing temperature between -5 and -25 deg.C within temperatures with -30 deg.C as the lower limit temperature. Because of the fact as described above, the iced form is defined as a thermostatic iced form. The material affording such a thermostatic iced form is e.g. ammonium chloride, sodium thiosulfate, ammonium nitrate, ammonium sulfate, potassium chloride, sodium chloride, sodium nitrate. The above-mentioned iced form maintains a peculiar low temperature at an ambient temperature of 17-20 deg.C for 2-3 h when 125-150 g thereof is placed in a polyethylene container 1 mm thick; when held in a thermal insulation container, it maintains such a temperature as to enable other object(s) to be frozen for 7-15 h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating agent capable of maintaining a constant low temperature and freezing other objects, and a constant temperature refrigerating device and a rapid cooling device using the refrigerating agent.

[0002]

2. Description of the Related Art Conventionally, there are many types of refrigerants called cold insulators and cold storage agents, and they are used for cooling objects for a long time. At present, these refrigerants are of a nature whose temperature gradually rises, so they have the effect of keeping cool, but have no power to freeze other things for a long time, Poor cooling power. In order to keep other things in a frozen state for a long time, it is necessary that the thing itself keeps -10 ° C or less continuously. Dry ice having such a capability is used for frozen transportation. However, dry ice requires special manufacturing equipment for its manufacture, is not easy to manufacture, and has a fatal defect in terms of simplicity. Further, there is a problem that carbon dioxide gas is generated at a high concentration, which deteriorates the product and makes breathing difficult.

[0003] In recent years, for the purpose of refrigeration, in addition to the above-mentioned conditions, a constant-temperature refrigeration body that maintains a constant low temperature has been required. A cryogen based on this new concept has not yet been put to practical use.

It is well known that the water point of an aqueous solution of an alcohol, a saccharide, or an inorganic salt drops due to a freezing point drop. However, for example, 1 which solidifies at −15 ° C.
0% saline becomes ice in a home freezer (-20 ° C), but melts in a short time and cannot be used as a substitute for dry ice.

[0005] There have been no reports yet as to whether the frozen body maintains a constant temperature and has the ability to freeze other objects for a long time comparable to dry ice.

[0006] Further, some conventional regenerators have been made into a sol or gel by adding a superabsorbent polymer.
Nothing that can be used as a constant temperature cryogen has yet been identified.

[0007]

SUMMARY OF THE INVENTION The present invention has been made under such a technical background, and it has been proposed to keep other objects in a frozen state for a long time, such as dry ice, or to rapidly cool them. To provide a refrigerating agent having a sufficient refrigerating capacity to maintain the temperature for a long time, and a refrigerating agent that can be manufactured in a general freezer, and a constant temperature refrigerating source device and a rapid refrigerating device using the same. And

[0008]

SUMMARY OF THE INVENTION In order to rapidly cool or freeze other objects and keep the frozen state, it is not preferable that the temperature rise and change with time. Further, even if the biological sample, food, meat, and the like are in a frozen state, if the temperature rises and changes over time, tamper modification, deterioration, or freshness change occurs, which is not preferable. From a practical point of view, it is necessary to know the temperature history of what was in a frozen state. For this reason, there is a need for a constant-temperature cryogen that has the ability to keep other things in a frozen state and that can always keep its temperature constant.

[0009] Now, assuming a situation in which other products are kept in a frozen state and transported, the temperature gradient caused by the container containing the cryogen is currently determined by using a material having good thermal conductivity. Also occurs at 2 ° C. In addition, the temperature distribution in the insulated container containing the cryogen and other items is 2 to 3 ° C. (generally, the bottom is low and the top is high). Therefore, in order to keep the temperature below freezing in transportation,
A 7 ° C. cryogen is required. -10 ℃ for safety
Let's be. In addition, a freezing agent at -5 ° C or lower is required for freezing other objects by direct contact.

Next, if a special device is required for producing such a constant-temperature cryogen, the industrial merit is drastically reduced.

[0011] Therefore, in order for such a freezing agent to be widely used widely and to obtain a great economic effect, it is required that the freezing agent can be manufactured in a general freezer.

According to a study by the inventor, the lower limit of a freezer compartment of a general household refrigerator is −21 ° C. according to Japanese Industrial Standards, and −26 ° C. is the limit even for a foreign-made refrigerator having a particularly cool power. On the other hand, in general industrial use such as wholesalers, freezers having a lower limit of -30 ° C are widespread, and the number of freezers below this is small. In addition, it is necessary to consider an error due to a temperature measurement of 1 to 2 ° C. in the temperature described in this specification.

[0013] For these reasons, in each user-
A constant temperature cryogen that can be produced at 30 ° C. or −21 ° C. is required. In particular, products that can be manufactured at −21 ° C. can be manufactured in home refrigerators, and the industrial merits become immeasurable.

As described above, a first object of the present invention is to provide a refrigerating agent which can be manufactured in a general freezer, and which can maintain a specific freezing temperature for a long time.

[0015] Since such a freezing agent is made of a substance which becomes a frozen body, a frozen body made of such a substance is defined as a constant temperature frozen body in the present invention.

[0016] As in the present invention, there is a restriction that a substance which becomes a constant temperature frozen body can be obtained at a temperature having a lower limit of -21 ° C, and a restriction that the substance itself is -5 ° C or less is added. It will be limited. In particular, the condition that the lower limit is −21 ° C. and a temperature of −10 ° C. or less can be obtained is particularly difficult. For example, an aqueous solution of calcium chloride
It freezes at -80 ° C, but remains a solution at -30 ° C. Even a mixed solution of ethanol and water or an aqueous solution of potassium thiocyanate or lithium chloride does not become frozen even at −30 ° C. Ammonium thiocyanate becomes frozen at −30 ° C., but the holding time of the freezing temperature is short, and the low temperature cannot be held for a long time. Ethylene glycol is also a sign. Also,
Sodium carbonate, potassium nitrate, sodium sulfate, magnesium sulfate and the like have a high frozen body temperature and do not meet the condition of -5 ° C or less.

As a result of conducting experiments on 50 kinds of substances, the inventor has found seven substances, ie, ammonium chloride, sodium thiosulfate, ammonium nitrate, ammonium sulfate, potassium chloride, sodium chloride, and sodium nitrate, as substances that become frozen at constant temperature. . Each of these frozen bodies has a unique low temperature for 2 to 3 hours even under severe conditions of putting 125 to 150 g each in a polyethylene container having a thickness of 1 mm and leaving it at room temperature of + 17 ° C to + 20 ° C. Maintained. In addition, when these substances were held in an insulated container such as Styrofoam or the like, the temperature at which each of the other substances could be frozen was maintained for 7 to 15 hours.

The refrigerating agent which maintains the refrigerating temperature for 7 to 15 hours brings a great practical advantage. That is, most of the current business hours of the company are from 9 to 17:00, and items to be kept frozen at 10:00 in the morning are put in a styrofoam container together with this freezing agent and sent to the destination. If we arrive at that time, it will take 6 hours. In consideration of such circumstances, a refrigeration agent that can maintain a constant temperature for at least 6 hours is required. However, the refrigeration agent that maintains the refrigeration temperature for 7 to 15 hours described above is sufficient for this requirement. It can respond, and its practical merits are great.

The characteristics of the above seven refrigerating agents are important, and are summarized as follows.

(1) The refrigerating agent of ammonium chloride is easily frozen in a general household refrigerator in a short time. Freezing time is short. The constant temperature holding time is also a medium length. Further, it has an excellent feature that the amount of reagent is only 20%, which is the minimum among substances.

(2) The refrigerating agent of ammonium nitrate is frozen in a general household refrigerator, but requires a relatively long time. However, it has a large heat of fusion, and has a long constant temperature holding time of 2 to 1.5 times as compared with others. This holding time is the same as for dry ice of the same weight and can replace dry ice.

(3) The refrigerating agent of ammonium sulfate is easily frozen in a general household refrigerator in a short time. The constant temperature holding time is short.

(4) The refrigerating agent of potassium chloride is frozen in a general household refrigerator in a short time. The constant temperature holding time is moderate, but the low temperature is -10 ° C, which is on the border of the requirement for frozen transportation.

(5) The characteristics of the sodium chloride cryogen are different from those of other cryogens in that the melting process changes from a solid to a semi-solid or semi-sorbet. And finally a saline solution.

Since the sherbet has the same function as the frozen matter, it is a freezing agent having no temperature unevenness as a whole. For this reason, there is a feature that uniform refrigeration without temperature distribution is possible and the refrigeration effect is good. Since the melting of the sherbet takes a considerable amount of time, the holding time at the freezing temperature is equivalent to that of ammonium chloride.

All other cryogens melt from solids to liquids, but as the amount of liquid increases, a slight temperature gradient occurs. This phenomenon is particularly remarkable in sodium thiosulfate.

(6) The sodium nitrate refrigerating agent takes a long time to become frozen in a general household refrigerator. The low temperature holding time is moderate. The temperature is the lowest of the six except for sodium chloride.

(7) Sodium thiosulfate is easily frozen in ordinary household refrigerators. However, the constant temperature is −8 ° C., which is in the form of a border line required for the present invention.

By the way, each of the above seven kinds of substances is taken, an aqueous solution having a concentration giving the lowest temperature as a weight percentage is prepared, put in a container, and left overnight in a freezer for 2 to 2 days to obtain a frozen product. The measured temperatures of the seven types of frozen bodies were as follows.

That is, a 33% solution of sodium nitrate is-
16 ° C, 38% ammonium sulfate solution at -15 ° C, 20% ammonium chloride solution at -14 ° C, 40% sodium thiosulfate pentahydrate solution at -8 ° C, ammonium nitrate solution at 3%
0% solution is -15 ° C, 20% solution of potassium chloride is -10 ° C
Met.

It should be noted that when the concentration is reduced, the properties as a constant temperature frozen body are not lost, but the temperature becomes higher. Therefore, the lowest temperature is obtained at the above-mentioned concentration.

Most of the mixture of the seven substances does not result in constant temperature frozen bodies.

The above seven substances are the main components, and another substance may be added in a small amount. In this case, the temperature of the frozen body may increase slightly or the constant temperature may deteriorate slightly.

[0034] Further, even if it is a substance which does not conform to the solution of the problem of the present invention even though it becomes a constant-temperature frozen body, the substance is not suitable for solving the problem of the present invention due to a low freezing temperature or a short retention time, , Compatible substances may be obtained. An example is shown in Example 5.

Of the above seven substances, in a general household refrigerator freezer (−21 ° C.), it becomes a constant temperature frozen body which is low enough to freeze other substances in a short time, and maintains the freezing temperature. The best long-lasting material is ammonium chloride. Ammonium nitrate is a substance that gives a longer freezing time, but provides a lower freezing temperature than ammonium chloride, and gives a longer freezing time for keeping the freezing temperature comparable to dry ice.

A second object of the present invention is to provide a thermostatic cryogen which can maintain the refrigeration temperature for a longer period of time, that is, a viscous cryogen obtained by adding a polymer to a liquid which becomes a thermostatic frozen body. It is in. Whether or not the cryogen obtained by freezing such a viscous liquid has a thermostatic property,
Not reported so far. Furthermore, it is not well known whether a high-concentration salt solution and a water-soluble polymer are compatible with each other and become frozen in a general freezer.

The refrigerating agent is composed of a mixture of a solution which becomes a frozen body at a temperature lower than −21 ° C. and a water-soluble polymer.

A water-soluble polymer other than the polymer electrolyte, for example, polyvinylpyrrolizone, becomes a viscous liquid when a solution that becomes a constant temperature frozen body is added, and becomes a constant temperature frozen body. Unless several tens of percent is added, sufficient viscosity cannot be obtained, and the practicability is poor.

Next, a solution having a constant temperature at −21 ° C. and having a power as a freezing agent, that is, ammonium chloride, ammonium nitrate, potassium chloride, sodium nitrate, and ammonium sulfate, was prepared from sodium dextran sulfate, carboxymethylcellulose, and alginate. When the compatibility was examined using three polymer electrolytes, all were compatible and became a highly viscous liquid. All of these gels were frozen in a home freezer and had a constant temperature (Example 10). However, ammonium sulfate 38%
The heavy liquid did not dissolve, but the 10 wt% liquid did.
This is considered to be because the network structure of the gel was broken with the high-concentration salt.

As the polymer electrolyte, dextran type,
There are various types such as starch type, cellulose type and synthetic polymer type, but basically dextran sulfate type, polyacrylic acid type, carboxymethylcellulose type and alginic acid type are mainly used.

The above-mentioned mixture is obtained by preparing a 5 to 30% by weight solution (ammonium sulfate is 20% or less) with respect to a substance which becomes a frozen body and adding 0.1 to 10% by weight of a polymer electrolyte and mixing well. Can be Alternatively, it can be obtained by dissolving a polymer electrolyte in a predetermined amount of water and adding a predetermined amount of salt thereto. However, this amount is an approximate amount, and the weight% varies depending on the constant temperature frozen body that maintains the target temperature. Even if the polymer electrolytes are the same, the viscosity is completely different depending on the degree of polymerization, and the higher the degree of polymerization, the higher the viscosity even if the amount is small.

By adding the polymer electrolyte, the holding time of the freezing temperature becomes longer by that amount.
Even when the amount of the carboxymethylcellulose polymer was increased from 2.5% to 5%, there was no significant difference in the holding time at the freezing temperature. This means that there is no difference in the effect even if it exceeds a certain amount.

The comparison of the difference in the freezing temperature holding time between the case where the polymer was added and the case where the polymer was not added is as follows. That is, 100 ml of a 20% ammonium chloride solution itself and a mixture of 5% carboxymethylcellulose and 100 ml of the mixture were frozen at −21 ° C. and left at 25 ° C. room temperature. The 20% solution itself is always at −15 ° C., melts in 1 hour and 50 minutes,
After 0 minute, the temperature was 10 ° C. The one with 5% polymer was always at -15 ° C, but melted in 2 hours and 10 minutes.
After 2 hours and 20 minutes, the temperature was 4 ° C. If two liters of liquid are compared in an insulated container, the difference between the case where the polymer is added and the case where the polymer is not added is 5 hours.

A third object of the present invention is to provide a constant-temperature refrigeration source device in which the above-mentioned cryogen is housed in a heat insulating container. This apparatus is characterized in that the temperature inside the container can always be kept at a constant freezing temperature for a long time without using a cooling difference separately, since the above-mentioned constant temperature frozen body is used as a freezing source.

The heat insulating container referred to here is made of a thick material having a low thermal conductivity and a space for accommodating a cryogen and other objects.
For example, paper, dried wood, feather, wool, charcoal, cotton, carbon fiber, foamed plastic, elastomer, and the like having a large air content are suitable.

Basic materials such as those obtained by finely bundling and synthesizing chemical fibers such as nylon, glass wool, those having a double structure of plastic or paper and having a space inside, or those in which a foam is filled are used. Since the thermal conductivity of air is minimal, anything with a high content can be used as a material.

The heat-insulating container can be defined as having such a material, and capable of storing a refrigerating agent and a frozen object, and having a reduced heat exchange with the outside.

A constant temperature refrigeration source device is one in which the constant temperature frozen body of the above-mentioned refrigerant is put in an insulated container, or the whole of the insulated container is frozen to obtain a constant temperature frozen body, which is capable of maintaining a specific low temperature for a long time. is there. If used for frozen storage or transportation, it can be extremely useful in industry.

For confirmation, the above-mentioned constant-temperature iced product was placed in an insulated container, and an experiment was carried out using it for actual frozen transportation. As a result, the following advantages were obtained.

(1) As shown in the examples, it was found that a styrene foam insulated container used for home delivery or the like can be kept frozen for about 20 hours.

(2) The constant temperature frozen body is kept at a constant temperature until the frozen body is melted, but the temperature of the melted liquid portion becomes non-uniform,
The thermostat weakens. However, vibrations and fluctuations occur in refrigerated transportation and transportation, and non-uniformity in temperature hardly occurs. That is, the characteristics of the constant temperature frozen body are perfectly exhibited.

(3) Because of the constant temperature, the substance can be kept frozen at the temperature of the frozen body, so that the substance is not denatured or deteriorated.

(4) Conventionally used dry ice sublimes. Therefore, the volume occupied by dry ice in the heat insulating container decreases with time. For this reason, the one placed at a position away from the dry ice melts. The drawbacks of dry ice are significant, but the constant temperature frozen and packaged do not.

(5) If the dry ice sublimates, the temperature in the heat insulating container rises rapidly, so that the time limit must be strictly adhered to. However, the time limit depends on the environmental temperature and cannot be predicted. It becomes a big problem when there is a situation such as refrigerated transportation that does not arrive within the time limit. Therefore, more dry ice than necessary is used for safety. After freezing, the frozen
It has an excellent property that the liquid temperature changes into a cooling agent that gradually increases, and as a result, the temperature in the heat insulating container gradually increases, so that the time limit is loose.

(6) In refrigerated transportation, if the frozen object and the target object move and change position due to vibration or swing unless the frozen object and the target object are tightly fixed, the temperature of the target object rises. There is.

Assuming such a case, the freezing temperature must be about -15 ° C. or lower. As the constant temperature frozen body anticipating such safety, three kinds of ammonium chloride, ammonium nitrate and sodium nitrate have been found, and if these are used, it is possible to respond.

As described above, the constant temperature frozen body exhibits an advantage particularly in frozen transportation. In particular, (4) and (5) are superior to dry ice. It turned out that it was not inferior to dry ice overall.

A fourth object of the present invention is to provide a rapid device in which a cryogen is filled into a bag or container having good heat conductivity.

The conventional bag or container filled with the cooling agent and frozen at −20 ° C. does not have constant temperature, so that even if the latent heat of fusion is large, the ability of rapid cooling is inferior.

The ability of rapid cooling is exhibited only when both a low temperature and a property for keeping the temperature constant are provided, and is not determined only by the magnitude of the latent heat. Therefore, if constant-temperature frozen matter is used for rapid cooling, an effect that cannot be obtained with the conventional accumulating agent can be expected.

A typical example of a bag or container having good thermal conductivity is a plastic bag or container made of aluminum, such as polyethylene, polypropylene, polyvinylidene chloride, or vinyl chloride. The bag or the container has, for example, a cylindrical shape, and contains a beer can, a beer bottle, a juice can, a plastic bottle, and the like. It is desirable that the outer surface be heat insulating. That is, it is desirable to attach a heat insulating sheet such as styrofoam or a heat insulating nonwoven fabric to the outer surface.

This is put in a freezer compartment of a home refrigerator, and the liquid in the refrigerator is used as a constant temperature frozen body.

[0063]

(Example 1) Two 300 g of a 20% aqueous solution of ammonium chloride, a special grade reagent, were prepared and left in a freezer (-20 ° C) overnight to obtain a frozen product. This is at room temperature (+ 17 ° C to + 20 ° C) until complete melting, for 2.5 hours,
12 hours each in a 25-cm-wide, 15-cm-long, 15-cm-high, 2-cm-thick styrene foam insulated container
2 ° C. to −14 ° C. was maintained.

(Example 2) Two 350 g of 38% aqueous solutions of ammonium sulfate, a special grade reagent, were prepared and placed in a freezer (-20
C) overnight to freeze. This is -1 until melting
8 ° C. was maintained. When two pieces of the same frost were still contained in the heat insulating container of Example 2, the temperature was kept at -12 ° C to -15 ° C for 12 hours.

Example 3 Two 300 g of a 31% aqueous solution of special grade ammonium nitrate were made in a freezer (−20).
℃) overnight to obtain a frozen body. It was kept at -13 ° C to -15 ° C, respectively, for a surprising time of 3 hours at room temperature (+ 17 ° C to + 20 ° C) until complete melting and 15 hours in the styrene foam insulated container of Example 2.

Example 4 Special grade reagent potassium nitrate 1
3.5 g and 26 g of ammonium chloride were dissolved in 100 g of water and frozen in a freezer at -20 ° C. It took 3 days to become frozen, but in the container of Example 2, the temperature was -14 ° C to -1.
7 ° C. was maintained for 10 hours.

Example 5 Ammonium chloride 20% solution 5
00 g was put into a PVC bag of IceNon to make a thermostatically frozen product, then two 100 g were put into an aluminum laminate bag to make a thermostatically frozen product, which was put into the styrofoam container of Example 1 together with 500 g of frozen serum at 3:00 pm. I sent it out at 4:00 pm by Cool Takkyubin and received it at 10:00 the next morning. It was completely frozen, and then left at room temperature (25 ° C.) until 3:00 pm, but it was still frozen. The isothermal ice melted at 3 pm.

For reference, two commercially available chill-first and cool one 100 g chillers were added to -2.
Ice was put in a freezer at 0 ° C., put in the heat insulating container of Example 1, and the temperature at the bottom was measured. On the other hand, two pieces of 100 g of constant temperature frozen matter containing 20% of ammonium chloride were iced at -20 ° C, and the same measurement was performed.

As a result, chill first and cool one were -10 ° C., -20 ° C., -11 ° C., 30 minutes after 10 minutes.
Minutes, -7 ° C, 40 minutes, -5 ° C, 60 minutes, -1 ° C
Then, the temperature rose sequentially. However, the constant temperature freeze is 1
0 minutes later, -14 ° C, 20 minutes later, -13 ° C, 30 minutes later,-
The temperature was 13 ° C., 40 minutes later, −13 ° C., 60 minutes later, −13 ° C., and no temperature change was observed.

Example 6 Ammonium chloride 20% solution 1
00 g and 105 g of a gel obtained by adding carboxymethylcellulose to 5% of this were frozen at −21 ° C., placed on a wooden laboratory table, left at room temperature 27 ° C., and the temperature immediately below the frozen It was measured with a thermistor thermometer.

As a result, after 1 hour,-
At 13 ° C for 1 hour and 30 minutes-13 ° C for 1 hour and 45 minutes
8 ° C, 0 ° C after 2 hours, 10 ° C after 2 hours and 20 minutes
It became. For gel type, -13 until 1 hour and 45 minutes
The temperature became -5 ° C after 2 hours and 4 ° C after 2 hours and 20 minutes.

In this experiment, since the amount was as small as 100 g and the environment was as high as 27 ° C., it was difficult to maintain a constant temperature due to a large heat inflow. Still one hour 30
Minutes are constant temperature. Thus, the gel type allows the temperature to be the same as the freezing properties of the solution itself, but the duration is longer. Also, the rate of temperature rise after melting is small. As a result of comparison at the same volume, the disappearance time of dry ice and the freeze-thaw time of the gel body are the same.

In the experiment, by making the volume of the 20% ammonium chloride solution 1.1 times that of the dry ice, the disappearance time of the dry ice and the melting time of the frozen matter were the same.
However, in this case, the time to keep other things in a frozen state was longer in the frozen body. This is because when the amount of dry ice becomes small, even if it remains, there is no power to keep other things in a frozen state.

(Embodiment 7) 2.6 cm thick, 28 c long
m, 35 cm in width and 22 cm in height (both inner dimensions), three 770 g / piece of dry ice were placed in the first container of styrofoam containers, and 820 was placed in the second container.
g of 20% ammonium chloride solution frozen at −21 ° C. are placed in a pile, and 860 g of 20% ammonium chloride of 5% gel-like carboxymethylcellulose is frozen at −21 ° C. in a third container. The melting time was measured for each sample starting at 5 o'clock in the evening and compared. Room temperature was 28-30 ° C.

The results were as follows. That is, at 9 o'clock the next morning, the dry ice remaining amount was about 200 g,
At 20% ammonium chloride one melted and the other two melted slightly less than 2/3. At 11:00 pm, the dry ice weighed about 50 g and the ammonium chloride was almost thawed. All gelled ice melted at 3 pm.

The reason for using 820 g of ammonium chloride with respect to 770 g of dry ice is that the amount was determined in consideration of the specific gravity.

As described above, when compared with the same volume,
The holding time at the freezing temperature is slightly shorter in the ammonium chloride solution than in the dry ice. However, when the remaining amount of dry ice becomes small, other things begin to melt. On the other hand, even if the frozen ammonium chloride melts, the temperature is kept below the freezing point for 3 hours. Considering this point, both can be said to be almost equivalent. It was found that the gel-like frozen body had the power to separate the two far apart and keep other things frozen for 24 hours even in summer.

(Example 8) Thickness 1.75 cm, height 17c
200 g of serum is placed in a styrofoam box measuring 18 cm in width and 18 cm in width and 14.5 cm in height (both internal dimensions). Two 550 g of a 550 g% sodium chloride solution were frozen at -20 ° C. 200 g of frozen serum in a similar box prepared separately
, And a piece of paper was laid thereon, and 1 kg of dry ice was placed on the piece of paper.

The two boxes were sent by Takkyubin at 16:30 in the evening and received at 10:00 the next morning. At this point, both sera were frozen. The frozen ammonium chloride melted at 11:30 am. Dry ice disappeared at 12:30. At 2:00 pm, the frozen ammonium chloride was completely thawed, but the serum was frozen.
However, the serum on the dry ice was thawed. Such phenomena occur because of the properties of the constant temperature iced body of the present invention,
That is, it is due to the property that the thermostatic property disappears after melting, but thereafter, it is converted to a cooling agent whose temperature gradually rises. In addition, the power of keeping the low-temperature state as a cooling agent for a long time was larger in the 20% solution than in the 15% solution and the 20% solution.

(Example 9) 350 ml of canned beer at 30 ° C was prepared using VACU PRODUCTS SB.
V. The beer was placed in Rapid Ice (frozen at −20 ° C.) and the temperature of the beer after 15 minutes was measured. On the other hand, the contents of the same rapid ice were replaced with the same weight of 20% by weight ammonium chloride, frozen at −20 ° C. to form a constant temperature frozen product, and 350 ml of can beer at 30 ° C. was put into the frozen beer. After 15 minutes, the temperature of the beer was measured. The measurement result was 16, 13, 11 ° C for rapid ice, but was 8, 5, 4 ° C for constant-temperature frozen matter. Thus, the short-time cooling power is remarkably excellent.

[0081]

According to the present invention, it is possible to provide a refrigerating agent which can be manufactured in a freezer or a freezer of a home refrigerator, can last as long as dry ice, and can maintain a constant temperature. This substance, which becomes a frozen substance, can be obtained by placing it in a freezer overnight or several days, and its temperature is much lower than the freezing point, and it is also a constant temperature, making it ideal for freezing reagents, fish and food. Agent.

The freezing agent of the present invention, in addition to the above-mentioned excellent properties, is not inferior to a dry ice as a freezing agent, and is also used as a frozen body in a freezing room owned by a user before use. Because of its simplicity of use, its industrial utility is significant.

Further, according to the present invention, by placing this cryogen in a container capable of shutting off the outside air, 7 to 15
It is possible to provide a refrigeration source device that keeps a constant temperature of −10 ° C. to −21 ° C. over time and keeps a target in a frozen state for 24 hours.

Further, according to the present invention, since the polymer electrolyte is added to the above-mentioned refrigerating agent, the time for keeping the refrigerating temperature is long,
In addition, a refrigerating agent having a constant temperature property can be provided. Further, since the refrigerating agent is filled in a bag or a container having good heat conductivity, it is possible to obtain a rapid cooling device capable of rapidly cooling other objects.

Claims (5)

[Claims] 1. At a temperature having a lower limit of −30 ° C.,
A refrigerating agent comprising a substance capable of obtaining a constant temperature frozen body that continuously maintains a refrigerating temperature in a range of 5 ° C. to −25 ° C. 2. At a temperature having a lower limit of −21 ° C.,
A refrigerating agent comprising a substance capable of obtaining a constant temperature frozen body that continuously maintains a freezing temperature in a range of 5 ° C to -18 ° C. 3. The method according to claim 1, wherein a water-soluble polymer is added.
The cryogen described. 4. A constant temperature cooling device comprising the cryogen according to claim 1, 2 or 3 housed in a heat insulating container. 5. A rapid cooling device comprising a refrigerating agent according to claim 1, 2 or 3 filled in a container having good thermal conductivity.