JP2003041242A - Mixed cold reserving agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To find a combination of mixed salts which can become a useful cold storing agent. SOLUTION: The cold storing agent comprises combining identical negative ions with corresponding different positive ions thereto in monovalent salts or bivalent salts. Examples of the agent in order from a high temperature side are an aqueous solution of 23% sodium chloride, an aqueous solution of 17% sodium chloride - 5% ammonium chloride, an aqueous solution of 15% magnesium chloride, and an aqueous solution of 15% magnesium chloride - 5% calcium chloride.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold insulating material and a cold storage agent. Here, the agent means an aqueous solution containing the component, and the cold insulating material means a container filled with the cold storage agent.

[0002]

2. Description of the Related Art For mixed cryogens, NH ₄ Cl and K
NO ₃ , NaNO ₃ and NH ₄ NO ₃ , KNO ₃ and NH ₄
SCN and the like are known. However, there are no reports on cold storage agents. In addition, a regenerator that provides a low temperature of -35 ° C or lower, which is an alternative to dry ice, has not been found.

[0003]

A combination of salts is found that gives a useful regenerator when made into an aqueous solution and frozen. Moreover, a regenerator which keeps a low temperature of −35 ° C. or lower is found.

[0004]

The inventor has found that a salt prepared by mixing salts having the same anion but different cations can be a useful cold storage agent.
Among the anions, chloride ions and nitrate ions have an effect. Cationic ions are classified into monovalent salts and divalent salts. Sodium ions, potassium ions, and ammonium ions are useful as cations of monovalent salts, and magnesium ions and calcium ions are practically used as divalent cations. It is useful.

The mixture has the same anion, but the corresponding cations must have the same valence, such as monovalent and monovalent, and divalent and divalent. For example, a combination of a monovalent sodium ion and a divalent magnesium ion as a cation with respect to a chloride ion (monovalent) is not used.

In the present invention, for monovalent salts, chloride ions (Cl ⁻ ) are most preferable as anions, and sodium ions (Na ⁻ ), potassium ions (K ⁻ ), and ammonium ions (NH ₄ ) as cations. ^-) of the two-component mixture is preferred. A mixture of 3 kinds may be used, but it was not improved further than 2 kinds. The reason why Cl ⁻ is preferable is that, as a result of various experiments, phenomena such as a remarkable decrease in melting temperature and an increase in retention time were observed in chloride ions. The cations of the divalent salt are magnesium ion (Mg ²⁺ ) and calcium ion (Ca
²⁺ ) is preferable, and a chloride ion is also preferable as the counter anion.

Therefore, the preferred specific combination of the present invention is, as a monovalent salt, NaCl and KCl, and NaCl and NH _4.
It becomes Cl, KCl and NH ₄ Cl. In the divalent salt, MgCl ₂ and CaCl ₂ are used as chlorides. Either of these two combinations may be the main component.

Among the divalent salts, when the anion is a chloride ion and the cation is a combination of calcium ion and magnesium ion, the melting point is lower than that of a single salt in the experiment,
The most favorable result is obtained in terms of increasing the holding time, and the temperature is the low temperature required for replacing dry ice.
C. (when calcium chloride is added to the magnesium chloride main component), -47.degree. C. (when magnesium chloride is added to the calcium chloride main component) and the like can be realized.

An embodiment of the present invention will be described, for example, with NaC.
1 or KCl as the main component, and NH ₄ Cl is added thereto in an amount of 1/2 to 1/10 of the amount of the main component, preferably 1/3 to 1/5. On the contrary, the main component is NH ₄ Cl, and NaCl or KCl is preferably added thereto in an amount of ⅓ to ⅕. In addition, in the single component regenerator, the amount is 1/3 to 1/5.
However, preferable results can be obtained even if the total amount is reduced by adding the corresponding component by the amount reduced. As an example of the above two ideas, for example, 20% by weight (-30 ° C.) of MgCl ₂ can be used as a single component regenerator, but this amount is used as a 15% by weight aqueous solution and CaCl ₂ is 5 It may be 7% by weight. Of course, MgCl ₂ 20
It is possible to obtain a result in which CaCl ₂ of 1/4 amount of 5 wt% is added to the wt% liquid. The main component concentration is preferably 1
0 to 25% by weight. Here, when the main component is 10% by weight, if the corresponding component is 1/4, it is 2 to 3%.
In the present invention in which the aqueous solution thus obtained is put in a container such as polyethylene and frozen to be used as a cold insulator,
Consider the concentration of the single component regenerator as a standard, but as a guideline, measure the holding time and select a concentration that is not too short.

[0010]

[Effect] In the present invention, (1) MgCl ₂ alone is -3
A mixture containing CaCl ₂ at 1 ° C. as its main component and CaCl ₂ has a low holding temperature of −35 to 37 ° C. and a holding time longer than that of a single MgCl ₂ product. Also, CaCl ₂ alone has a temperature of about −44 ° C., but the main component is CaCl ₂ and Mg
If Cl ₂ is mixed in, −48 ° C. is obtained. In this way, a lower temperature can be obtained by making the chloride ion the same and mixing a small amount of the same divalent alkaline earth metal. The low-temperature cold insulating material in which these are put in a container has a sufficiently low temperature that it can be a substitute for dry ice. (2) KCl alone has a temperature of -11 ° C at most, but N which is the same chloride ion but whose cation is a monovalent ammonium ion
When a small amount of H ₄ Cl was mixed, the temperature became −17 ° C., and the temperature decrease was extremely large. Further, although NaCl alone has a temperature of −20 ° C., a mixture containing NH ₄ Cl as a main component of NaCl has a low melting point of −25 ° C. and has a long holding time. (See FIG. 1) As described above, a cool storage agent superior to that containing only the main component can be obtained, and a cool storage agent suitable for various purposes can be obtained.

[0011]

[Example 1] A single cold storage agent containing a 23% aqueous solution of sodium chloride and an aqueous solution containing 17% of sodium chloride and 5% of ammonium chloride were frozen, and the melting temperatures were compared.
The former was -20 ° C and the mixed cold insulator was -25 ° C. The retention time was the same.

[0012]

[Example 2] A single cold storage agent containing 20% aqueous solution of potassium chloride and an aqueous solution containing 15% of potassium chloride and 5% of ammonium chloride were respectively frozen and the melting temperatures were compared. The former was -10.5 ° C, and the mixed regenerator was -17 ° C. The retention times were comparable.

[0013]

Example 3 A single regenerator with 20% ammonium chloride,
A regenerator containing 20% ammonium chloride and 5% potassium chloride was placed in a polyethylene container having a thickness of 1 mm and then frozen to compare the surface temperatures. The former is -16 ° C and the latter is-
Although the temperature was 17.5 ° C, the retention time of the latter was 1.15 times longer.

[0014]

Example 4 It is filled in a polyethylene container with a thickness of 1 mm and an inner volume of 550 ml and frozen, and one piece is 30 × 21 × 12 cm thick 2
The results are shown in the above table, in which the change in the surface temperature was put into styrene foam having a size of 10 cm and the change in the surface temperature was compared with that of the mixture alone. Magnesium chloride 15
% Alone has a melting temperature of −31 ° C., on the other hand, when calcium chloride is added thereto, the addition amount is 2.5%.
In the case of, the melting point was slightly lowered, and when 5% was added, a remarkable decrease was shown. This magnesium chloride of 15% and calcium chloride of 5% requires about 10 hours to reach -20 ° C and can be sufficiently put into practical use. Further, the melting point of magnesium chloride added to 20% and calcium chloride added thereto also lowers the melting point.

[0015]

Example 5 A single solution of 10% potassium chloride was -11 ° C.
However, the regenerator added to this so that the ammonium chloride content was 3% was -13 ° C.

[0016]

Example 6 A single solution of 15 to 17% by weight calcium chloride showed -44 ° C, while a mixture of 15% by weight calcium chloride and 5% by weight magnesium chloride was -47.5 ° C.
showed that.

[Brief description of drawings]

FIG. 1 shows a comparison of surface temperatures when two sets of cold insulating materials are set in the cold insulating box of Example 4 and four types of cold insulating materials are respectively put therein.

Claims (8)

[Claims] 1. A cold storage agent comprising two salts having a combination of cations of the same valence and different types and anions of the same type, wherein the valence is monovalent or divalent. 2. The regenerator according to claim 1, wherein the cation of the monovalent salt is any one of sodium ion, potassium ion and ammonium ion, and the cation is chloride ion. . 3. The regenerator according to claim 1, wherein the cation of the divalent salt is one of magnesium ion and calcium ion, and the anion is one of chloride ion. Agent. 4. The cold storage agent according to claim 1, wherein the main component concentration is 10 to 25% by weight. 5. The cold storage agent according to claim 2, which comprises sodium chloride and potassium chloride. 6. The cold storage agent according to claim 2, which is composed of potassium chloride and ammonium chloride. 7. The cold storage agent according to claim 3, comprising magnesium chloride and calcium chloride. 8. A cold insulating material obtained by filling the storage member with the cold storage agent according to claim 1 and freezing it.