JP6219653B2 - Cooler - Google Patents

Description

  The present invention relates to a cold insulator provided with a novel cold insulation composition.

  The cold insulator is widely used for cold storage during storage and transportation of various fresh products, and is usually used repeatedly. Such a cold-retaining tool includes a cold-retaining composition having a cold-retaining action, and is configured by enclosing the cold-retaining composition in a thermally conductive container.

As a conventional cold-retaining composition, a composition containing a solvent such as water as a main component and a salt is also widely used. However, some of these cold-retaining compositions have a large volume when solidified, and in this case, the container is deformed, causing troubles in storing the cold-retaining tool or being difficult to hold when carrying. There was a problem that it was easy to drop. Furthermore, in the worst case, there was a problem that the container could be damaged without being able to resist the pressure at the time of expansion of the composition for cold preservation.
On the other hand, a cold insulator in which a surplus space capable of allowing volume expansion of the cold insulation composition is provided in the container in advance has been proposed (see Patent Document 1).

JP 2003-171657 A

  However, the cold insulation tool described in Patent Document 1 has a problem that the amount of cold insulation is reduced because the extra space is provided, so that the cold insulation time is shortened. Further, the composition of the cold insulation composition is appropriately adjusted in accordance with the intended cold insulation temperature range, but if the composition is different, a difference occurs in the degree of volume expansion (volume expansion coefficient), so that it is required accordingly. The size of the surplus space is also different, and there is a problem that it is difficult to use one container in various cold insulation temperature ranges. Therefore, a novel cold-retaining composition that can suppress volume expansion at the time of solidification and can keep the object cold at a desired temperature for a long time has been desired.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the cold insulator provided with the novel composition for cold preservation which can hold | maintain the target object for a long time by suppressing the volume expansion at the time of solidification. .

To solve the above problems, the present invention, the eutectic point is an inorganic compound other than sodium chloride is -20 ° C. or less, and contains water, inorganic non-chloride the eutectic point is -20 ° C. or less A cold insulator provided with a cold insulation composition having a compound content of 0.45 to 5.5 mass% , wherein the cold insulation composition includes an inorganic compound having a eutectic point higher than -20 ° C, Any one or both of a solvent other than water may be contained, and in the composition for cold preservation, the eutectic point is −20 ° C. or less, the inorganic compound other than sodium chloride, and the eutectic point. The ratio of the content of the inorganic compound having an eutectic point higher than −20 ° C. to the total content of the inorganic compound higher than −20 ° C. is 92% by mass or less. , Water and the total content of solvents other than water Inorganic compounds other than sodium chloride having a solvent content ratio of 5% by mass or less and an eutectic point of −20 ° C. or less are calcium chloride, magnesium chloride, magnesium nitrate, zinc chloride, sodium bromide One or more selected from the group consisting of potassium iodide, sodium iodide, potassium carbonate, sodium hydroxide and potassium hydroxide, and the inorganic compound having a eutectic point higher than -20 ° C is sodium sulfate, sulfuric acid One or more selected from the group consisting of potassium and potassium chloride, the solvent other than water is an alcohol, and in the composition for cold preservation, the inorganic compound other than sodium chloride whose eutectic point is −20 ° C. or lower The cold-retaining tool is characterized in that the difference between the absolute value of the eutectic point and the absolute value of the freezing point of the cold-retaining composition is 15 or more. .

  ADVANTAGE OF THE INVENTION According to this invention, the cold insulation tool provided with the novel composition for cold preservation which can suppress the volume expansion | swelling at the time of solidification and can cool a target object for a long time is provided.

The cold insulator according to the present invention contains an inorganic compound other than sodium chloride having a eutectic point of -20 ° C or lower, and water, and the content of the inorganic compound is 0.3 to 7% by mass. It is characterized by having an object.
In the cold-retaining composition, an inorganic compound is used as an expansion inhibitor, and by defining the content within a predetermined range, the cold-retention composition is suppressed in volume expansion during solidification, and has a desired cold-retention temperature. It can be stably maintained for a long time. And the cold-reserving tool provided with such a cold-retaining composition suppresses deformation during solidification of the cold-retaining composition, is excellent in handleability during storage and carrying, and prevents breakage.

  As used herein, “eutectic point” means the freezing point of a solution in which a compound is dissolved in a solvent (water) at a saturated concentration.

The said composition for cold preservation uses water as the main component of a cold insulating agent.
The temperature at which the composition for cold preservation solidifies (freezes) is mainly determined by the type and content of the inorganic compound.

The inorganic compound functions as an expansion inhibitor and is not particularly limited as long as it is other than sodium chloride having a eutectic point of −20 ° C. or lower, but is preferably a hydrophilic inorganic compound, It is more preferably an ionic inorganic compound that dissociates into ions when dissolved in water. The inorganic compound preferably has a solubility in water at 20 ° C. of 40 g / 100 mL or more (40 g / more dissolves in 100 mL of water at 20 ° C.), and more than 50 g / 100 mL. More preferred. The inorganic compound may be either a hydrate or a non-hydrate.
The inorganic compound is preferably an inorganic salt or a hydroxide.

Examples of cations (metal ions) constituting the inorganic salt include alkali metal ions such as lithium ions (Li ⁺ ), sodium ions (Na ⁺ ), and potassium ions (K ⁺ ); magnesium ions (Mg ²⁺ ) and calcium ions. Ions of alkaline earth metals such as (Ca ²⁺ ); ions of transition metals such as iron ions (Fe ³⁺ , Fe ²⁺ ), copper ions (Cu ²⁺ , Cu ⁺ ); zinc ions (Zn ²⁺ ), aluminum ions (Al ³⁺ ) ions of Group 12 or Group 13 metals and the like.

As anions constituting the inorganic salt, halogen ions such as chloride ions (Cl ⁻ ), bromide ions (Br ⁻ ), iodide ions (I ⁻ ), sulfate ions (SO ₄ ²⁻ ), nitrate ions (NO) ₃ ^-); carbonate ions _(CO ^{3 2-);} bicarbonate ion (HCO ₃ ^-); hydrogen sulfate ion (HSO ₄ ^-); phosphoric acid ion _(PO ^{4 3-);} hydrogen phosphate ions _(HPO ^{4 2-} ); Dihydrogen phosphate ion (H ₂ PO ₄ ⁻ ); sulfite ion (SO ₃ ²⁻ ); thiosulfate ion (S ₂ O ₃ ²⁻ ); nitrite ion (NO ₂ ⁻ ).

  Preferred examples of the inorganic salt together with its eutectic point include chlorides such as calcium chloride (-55.0 ° C), magnesium chloride (-33.6 ° C), zinc chloride (-62.0 ° C); Bromides such as sodium bromide (−28.0 ° C.); iodides such as potassium iodide (−23.0 ° C.) and sodium iodide (−31.5 ° C.); magnesium nitrate (−32.9 ° C.), Nitrate such as calcium nitrate; carbonate such as potassium carbonate (−36.8 ° C.); nitrite such as potassium nitrite (−22.5 ° C.).

  Preferred examples of the hydroxide together with its eutectic point include alkali metal hydroxides such as sodium hydroxide (−28.0 ° C.) and potassium hydroxide (−65.0 ° C.).

  The said inorganic compound may be used individually by 1 type, may use 2 or more types together, and when using 2 or more types together, those combinations and ratios can be selected arbitrarily.

  The inorganic compound is selected from the group consisting of calcium chloride, magnesium chloride, magnesium nitrate, calcium nitrate, potassium carbonate, potassium nitrite, potassium iodide, sodium bromide, sodium iodide, zinc chloride, sodium hydroxide and potassium hydroxide. It is preferable that it is 1 or more types.

Content of the said inorganic compound of the said composition for cold preservation is 0.3-7 mass%, it is preferable that it is 0.4-6.5 mass%, and it is more preferable that it is 0.4-6 mass%. It is preferably 0.45 to 5.5% by mass.
When the content of the inorganic compound is equal to or higher than the lower limit, the composition for cold preservation has a higher effect of suppressing volume expansion during solidification, and when the content of the inorganic compound is equal to or lower than the upper limit, The composition for use is highly effective in keeping the intended cold keeping temperature stable for a long time.

The said composition for cold preservation may contain the arbitrary components which do not correspond to these in the range which does not impair the effect of this invention other than the said inorganic compound and water. Examples of the optional components include dyes; various known additives such as thickeners and preservatives; inorganic compounds not corresponding to the dyes and additives, eutectic points higher than −20 ° C .; and dyes and additives Non-corresponding organic compounds; sodium chloride (eutectic point -21.2 ° C.); solvents other than water, etc.
Arbitrary components may be used individually by 1 type, may use 2 or more types together, and when using 2 or more types together, those combinations and ratios can be selected arbitrarily.

  Examples of the dye include azo dyes, anthraquinone dyes, indigoid dyes, naphthol dyes, sulfur dyes, triphenylmethane dyes, pyrazolone dyes, stilbene dyes, diphenylmethane dyes, xanthene dyes, alizarin dyes, acridine dyes, quinoneimine dyes (azine dyes, oxazine dyes) Dyes, thiazine dyes), thiazole dyes, methine dyes, nitro dyes, nitroso dyes, cyanine dyes, tar dyes and the like.

  Examples of the thickener include carboxymethylcellulose (CMC), guar gum, hydroxypropyl guar gum, pectin, xanthan gum, tamarind gum, carrageenan, propylene glycol and the like.

  Examples of the preservatives include food preservatives and antioxidants, and examples include sodium pyrithione, paraben (paraoxybenzoate ester), protamine, and organic nitrogen sulfur compounds.

An inorganic compound having a eutectic point higher than −20 ° C. that does not correspond to the dye and the additive is not particularly limited as long as it satisfies such a condition. The thing comprised by the cation (metal ion) or anion similar to the case of the inorganic compound which is -20 degrees C or less can be illustrated.
Examples of preferred inorganic compounds having a eutectic point higher than −20 ° C. together with the eutectic point include sodium sulfate (−2.0 ° C.), potassium sulfate (−1.0 ° C.), ammonium sulfate (−18 Sulfates such as sodium nitrate (−18.0 ° C.), nitrates such as ammonium nitrate (−17.0 ° C.); potassium chloride (−10.9 ° C.), ammonium chloride (−15.6 ° C.) Such as chloride.

  Examples of preferable organic compounds that do not correspond to the dyes and additives together with their eutectic points include urea (-12.0 ° C.) and the like.

Among the above-mentioned optional components, the melting point of the composition for cold insulation for setting the cold insulation temperature to a target range by using the inorganic compound or organic compound, or sodium chloride in combination, which does not correspond to the dye and additive. Adjustment can be performed easily. Moreover, the composition for cold preservation can maintain the target cold insulation temperature stably for a long time. Thus, the inorganic compound, organic compound and sodium chloride are particularly suitable among the optional components.
In this specification, “inorganic compound” means “an inorganic compound other than sodium chloride having a eutectic point of −20 ° C. or lower” used as an expansion inhibitor unless otherwise specified.

  In the composition for cold preservation, the inorganic compound (expansion inhibitor) and the optional component that does not correspond to a solvent other than water (dye; additive; does not correspond to the dye and additive, eutectic point from −20 ° C.) The ratio of the content of the optional component not corresponding to a solvent other than water to the total content of the inorganic compound; organic compound not corresponding to the dye and additive; sodium chloride, etc.) is 95% by mass or less. It is preferably 92% by mass or less. When the content of the optional component is in such a range, the composition for cold insulation has more effects of suppressing volume expansion during solidification and a cold insulation effect of stably maintaining a target cold insulation temperature for a long time. Get higher.

Solvents other than water are preferably hydrophilic, and alcohols such as ethanol and 2-propanol are preferred.
In the cooling composition, the ratio of the content of the solvent other than water to the total content of water and the solvent other than water is preferably 10% by mass or less, and more preferably 5% by mass or less. . When the content of the solvent other than water is within such a range, the composition for cold insulation has an effect of suppressing volume expansion at the time of solidification and an effect of keeping the target cold temperature stably for a long time. Get higher.

  The difference between the absolute value of the eutectic point of the inorganic compound and the absolute value of the freezing point of the cold-retaining composition ([the absolute value of the eutectic point of the inorganic compound]-[cooling composition] The absolute value of the freezing point]) is preferably 15 or more. Such a cold-retaining composition has a higher cold-retaining effect for stably maintaining the intended cold-retaining temperature for a long time.

The said composition for cold preservation can be manufactured by adding and mixing each compounding component for comprising this.
The addition method and mixing method of a compounding component are not specifically limited, It can adjust arbitrarily so that each compounding component may melt | dissolve or disperse | distribute uniformly in the temperature higher than the freezing (coagulation) temperature of the composition for cold preservation.

At the time of blending each component, all the components may be added and then mixed, or some components may be mixed while being sequentially added, or all components may be mixed while being sequentially added. Good.
Examples of the mixing method include a method of mixing by rotating a stirrer or a stirring blade, a method of mixing using a mixer, a method of mixing by adding ultrasonic waves, and the like.
The temperature at the time of blending is not particularly limited as long as each blending component does not deteriorate, and can be set to 15 to 30 ° C., for example.

  In the composition for cold preservation, all of the components may be dissolved, or some of the components may be dispersed without dissolving, and the components that are not dissolved are uniformly dispersed. Is preferred.

  The composition for cold preservation is suitable for being solidified at −25 to −20 ° C. and stored by using an inorganic compound having an eutectic point of −20 ° C. or less.

  The cold-retaining composition is preferably one that can be solidified so as to have a part that has not been solidified (unfrozen part). Such a cold-retaining composition is particularly excellent in the effect of suppressing volume expansion during solidification.

  The cold-retaining tool according to the present invention includes the cold-retaining composition, and is configured, for example, by holding the cold-retaining composition by holding means such as a container that can enclose a liquid material.

  The material of the holding means is preferably transparent so that the held cold-retaining composition can be visually recognized. Specific examples include polyolefins such as polyethylene and polypropylene; polyamides; and synthetic resins such as polyesters. . Among these, polyolefin is preferable from the viewpoint of excellent low-temperature brittleness resistance, water resistance, chemical resistance, and the like, and high-density polyethylene that is easy to mold and has high strength is more preferable.

Since the volume retention at the time of solidification of the cold-retaining composition is suppressed, the cold-retaining tool can be configured by arbitrarily selecting a holding means having a desired shape and size.
The composition for cold insulation usually expands most when solidified. In the present invention, the reason why the volume expansion at the time of solidification of the composition for cooling is suppressed is not certain, but as described above, a specific inorganic compound is selected and its content is limited to a specific range. As a result, in addition to the volume expansion during solidification being suppressed, the cold-retaining composition also has a higher cold-retaining effect for stably maintaining the intended cold-retention temperature for a long time.

  The cold insulation tool according to the present invention is sufficiently filled with the cold insulation composition so as not to generate an excessive space (gap) that allows (absorbs) the effect of volume expansion during solidification of the cold insulation composition. In this state, the expansion coefficient calculated from the measured value of the expansion amount at a predetermined position during solidification can be 30% or less. Here, the amount of expansion of the cold insulator is, for example, the distance between two opposing surfaces such as the two main surfaces of the cold insulator encapsulated with the cold insulation composition (for example, when the holding means is flat) Is measured at the same location before and after cooling the composition for cooling, and after the solidification of the composition for cooling, the difference between the distance after solidification and the distance before cooling ([after solidifying the composition for cooling) The distance between the two surfaces of the cold insulator]-[the distance between the two surfaces of the cold insulator before cooling the composition for cold preservation])). In the present specification, “before cooling” means a stage at room temperature (for example, 15 to 30 ° C.) before starting cooling unless otherwise specified.

  Further, the cold insulation tool according to the present invention is a time for maintaining the cold insulation temperature at 5 ° C. or less when the cold insulation composition is solidified and left at 30 ° C. (the temperature of the cold insulation composition itself is 5 ° C. or less). It is possible to set a certain period of time (cooling time) to 15 hours or more.

  The cold insulator according to the present invention is suitable, for example, for stably maintaining the cold insulation temperature in the vicinity of −5 to 0 ° C.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.

[Example 1]
<Manufacture of composition for cold preservation>
As shown in Table 1, an aqueous magnesium chloride solution having a concentration of 0.5% by mass was prepared as a composition for cold preservation.
In Table 1, “content (mass%)” means the content (concentration) of the expansion inhibitor (magnesium chloride) in the composition for cold preservation. Table 1 also shows the freezing point (° C.) of the composition for cold preservation. The same applies to the following examples and comparative examples.

<Manufacture of cold insulation>
The obtained cold insulation composition was sealed in a flat container having a capacity of 1000 g to obtain a cold insulation tool. At this time, an inevitable minute gap (a space not filled with the cold-retaining composition) was left in the container due to the operation of sealing the cold-retaining composition. In the evaluation, the size was such that the influence on the expansion amount of the cold insulator was negligible. This is the same in the following examples and comparative examples.

<Evaluation of expansion inhibiting ability of composition for cold preservation>
The obtained cold insulation tool (cold insulation composition) is placed in a predetermined place in the freezer, cooled to -25 ° C and stored at this temperature for 24 hours, and after the composition for cold insulation has completely solidified (cold insulation) The expansion amount of the composition was measured. The amount of expansion of the cold insulator is the difference between the thickness of the cold insulator after solidifying the composition for cold insulation and the thickness of the cold insulator before cooling ([for cold insulation] The thickness of the cold insulation after solidification of the composition]-[thickness of the cold insulation before cooling]). Then, from the value of the expansion amount, the expansion rate of the cold insulation tool after solidifying the cold insulation composition ([expansion amount of the cold insulation device] / [thickness of the cold insulation device before cooling] × 100) (%) was obtained. The results are shown in Table 1.

<Evaluation of cold performance of the composition for cold storage>
The cold-retaining tool (cold-retaining composition) obtained above was cooled to −25 ° C. and stored at this temperature for 5 hours to completely solidify the cold-retaining composition. Next, immediately place the cooler in a predetermined place in the cool box that has not been temperature-controlled, and then leave the cool box containing the cooler under a temperature condition of 30 ° C. to adjust the ambient temperature in the cool box. The time (min) at which the temperature can be maintained at 5 ° C. or lower (cooling time at 5 ° C. or lower) was measured. The results are shown in Table 1.

[Example 2]
As shown in Table 1, a composition for cold insulation and a cold insulator were manufactured in the same manner as in Example 1 except that the concentration of the magnesium chloride aqueous solution was changed to 2.5% by mass instead of 0.5% by mass. The composition for cold preservation was evaluated. The results are shown in Table 1.

[Example 3]
As shown in Table 1, a composition for cold insulation and a cold insulation tool were produced in the same manner as in Example 1 except that the concentration of the magnesium chloride aqueous solution was changed to 3% by mass instead of 0.5% by mass. The composition for evaluation was evaluated. The results are shown in Table 1.

[Example 4]
As shown in Table 1, a composition for cold insulation and a cold insulation tool were produced in the same manner as in Example 1 except that the concentration of the magnesium chloride aqueous solution was changed to 5% by mass instead of 0.5% by mass. The composition for evaluation was evaluated. The results are shown in Table 1.

[Example 5]
As shown in Table 1, an aqueous magnesium nitrate solution having a concentration of 2% by mass was prepared as a cold insulation composition. And the cold insulator was manufactured by the same method as Example 1 except the point which used this composition for cold preservation, and the composition for cold insulation was evaluated. The results are shown in Table 1.

[Example 6]
As shown in Table 1, a composition for cold insulation and a cold insulation tool were produced in the same manner as in Example 5 except that the concentration of the magnesium nitrate aqueous solution was changed to 5 mass% instead of 2 mass%, and the composition for cold insulation was produced. The thing was evaluated. The results are shown in Table 1.

[Example 7]
As shown in Table 1, an aqueous calcium chloride solution having a concentration of 2% by mass was prepared as a cold insulation composition. And the cold insulator was manufactured by the same method as Example 1 except the point which used this composition for cold preservation, and the composition for cold insulation was evaluated. The results are shown in Table 1.

[Example 8]
As shown in Table 1, a cold-retaining composition and a cold-retaining tool were produced in the same manner as in Example 7 except that the concentration of the aqueous calcium chloride solution was changed to 5% by mass instead of 2% by mass. The thing was evaluated. The results are shown in Table 1.

[Example 9]
As shown in Table 1, an aqueous solution containing sodium sulfate, potassium sulfate and magnesium chloride, having a sodium sulfate concentration of 5% by mass, a potassium sulfate concentration of 5% by mass and a magnesium chloride concentration of 1% by mass is prepared. And it was set as the composition for cold preservation. And the cold insulator was manufactured by the same method as Example 1 except the point which used this composition for cold preservation, and the composition for cold insulation was evaluated. The results are shown in Table 1.

[Comparative Example 1]
As shown in Table 2, a cold insulator was produced in the same manner as in Example 1 except that water was used instead of the cold insulation composition, and water as a cold insulation agent was evaluated. The results are shown in Table 2.

[Comparative Example 2]
As shown in Table 2, a composition for cold insulation and a cold insulation tool were produced in the same manner as in Example 1 except that the concentration of the magnesium chloride aqueous solution was changed to 0.25 mass% instead of 0.5 mass%. The composition for cold preservation was evaluated. The results are shown in Table 2.

[Comparative Example 3]
As shown in Table 2, a composition for cold insulation and a cold insulation tool were produced in the same manner as in Example 1 except that the concentration of the magnesium chloride aqueous solution was changed to 8 mass% instead of 0.5 mass%. The composition for evaluation was evaluated. The results are shown in Table 2.

[Comparative Example 4]
As shown in Table 2, an aqueous potassium chloride solution having a concentration of 2% by mass was prepared as a cold insulation composition. And the cold insulator was manufactured by the same method as Example 1 except the point which used this composition for cold preservation, and the composition for cold insulation was evaluated. The results are shown in Table 2.

[Comparative Example 5]
As shown in Table 2, a composition for cold insulation and a cold insulation tool were produced in the same manner as in Comparative Example 4 except that the concentration of the aqueous potassium chloride solution was changed to 5 mass% instead of 2 mass%, and the composition for cold insulation was produced. The thing was evaluated. The results are shown in Table 2.

[Comparative Example 6]
As shown in Table 2, an aqueous solution containing sodium sulfate and potassium sulfate, having a sodium sulfate concentration of 5% by mass and a potassium sulfate concentration of 5% by mass was prepared as a cold insulation composition. And the cold insulator was manufactured by the same method as Example 1 except the point which used this composition for cold preservation, and the composition for cold insulation was evaluated. The results are shown in Table 2.

  In each of the above examples and comparative examples, when the expansion rate is 30% or less, the expansion suppression ability is determined to be acceptable, and when the cold retention time is 15 hours or more, the cold insulation performance is determined to be acceptable. .

  As is clear from the above results, the inorganic salt having an eutectic point of −20 ° C. or lower is used as the expansion inhibitor, and the content is in the range of 0.3 to 7% by mass. The composition for use was remarkably suppressed in volume expansion at the time of solidification, and had a long cooling time at 5 ° C. or less, and was excellent in both expansion suppressing ability and cooling performance.

On the other hand, the composition for cold preservation of Comparative Example 2 is the content of the expansion inhibitor among the compositions for cold insulation of Comparative Examples 2 and 3 using the same materials as Examples 1 to 4 as the expansion inhibitor. The expansion inhibiting ability was inferior due to the small amount, and the cold insulation composition of Comparative Example 3 was inferior in the cold retaining performance due to the large content of the expansion inhibiting agent.
Moreover, the composition for cold preservation of Comparative Examples 4 and 5 using only the inorganic salt having a eutectic point higher than −20 ° C. as the expansion inhibitor was inferior in expansion suppression ability.
Moreover, the composition for cold preservation of the comparative example 6 which used together only 2 types of inorganic salt whose eutectic point is higher than -20 degreeC as an expansion | extension inhibitor was also inferior in expansion | swelling suppression ability.
The cooling agent of Comparative Example 1 that did not use the expansion inhibitor was also inferior in expansion suppression ability.

  In addition, using the magnesium chloride alone as the expansion inhibitor, the composition for cold preservation of Comparative Example 3 having a freezing point of −3 ° C., using magnesium chloride as the expansion inhibitor, and further using sodium sulfate and potassium sulfate in combination, From the comparison with the cold-retaining composition of Example 9 having a freezing point of −4 ° C., the cold-retaining composition has an eutectic point of −20 ° C. or lower even though the freezing point is substantially the same. In addition to this, it was suggested that the intended cold-retaining temperature can be stably maintained for a longer time by using an inorganic salt having a eutectic point higher than −20 ° C. in combination.

  The present invention can be used as a cold insulator for various fresh products.

Claims (1)

Eutectic point inorganic compounds other than sodium chloride is -20 ° C. or less, and contains water, the content of the inorganic compound other than sodium chloride the eutectic point is -20 ° C. or less 0.45 1-5. A cold insulator provided with a composition for cold preservation of 5 % by mass ,
The composition for cold preservation may contain one or both of an inorganic compound having a eutectic point higher than −20 ° C. and a solvent other than water,
In the composition for cold preservation, the eutectic with respect to the total content of the inorganic compound other than sodium chloride having the eutectic point of -20 ° C or lower and the inorganic compound having the eutectic point higher than -20 ° C. The proportion of the content of the inorganic compound having a point higher than −20 ° C. is 92% by mass or less,
In the cold insulation composition, the ratio of the content of the solvent other than water to the total content of water and the solvent other than water is 5% by mass or less,
The inorganic compound other than sodium chloride having an eutectic point of −20 ° C. or lower is calcium chloride, magnesium chloride, magnesium nitrate, zinc chloride, sodium bromide, potassium iodide, sodium iodide, potassium carbonate, sodium hydroxide, and One or more selected from the group consisting of potassium hydroxide,
The inorganic compound having a eutectic point higher than −20 ° C. is one or more selected from the group consisting of sodium sulfate, potassium sulfate and potassium chloride;
The solvent other than water is alcohol;
In the cold insulation composition, the difference between the absolute value of the eutectic point of an inorganic compound other than sodium chloride having a eutectic point of −20 ° C. or less and the absolute value of the freezing point of the cold insulation composition is 15 or more. cold tool, characterized in that it.