JP2017057377A - Cold insulation tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold insulation tool easily visible whether cooling condition is at aimed condition or not.SOLUTION: There is provided a cold insulation tool having a composition for cooling containing water, inorganic salt, a thickener and a pH indicator, wherein the composition for cooling contains acidic inorganic salt of which solution shows acidity and phosphate as the inorganic salt, percentage of total content of the acidic inorganic salt and phosphate to the total content of the inorganic salt is 5 to 100 mass%, the composition for cooling contains dihydrogenphosphate and the inorganic salt other than dihydrogenphosphate as the acidic inorganic salt, pKa of the pH indicator is 4.9 to 8.0 and pH (α1) when all contained component other than phosphate, dihydrogenphosphate and water satisfies a relationship represented by the following formula (i) to the pKa. pKa of pH indicator≤pH(α1)≤pKa of pH indicator+1.8 (i).SELECTED DRAWING: None

Description

  The present invention relates to a cold insulator provided with a cold insulating composition in which a color change during cooling can be easily visually recognized.

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 the composition for cold insulation, those containing a colorant are known so that the presence thereof can be easily visually recognized from the outside of the cold insulation device. For example, the composition for cold insulation colored with a dye is enclosed. A cold insulator whose disclosing amount can be easily confirmed from the outside is disclosed (see Patent Document 1).

JP 2006-97984 A

  However, the cold insulator described in Patent Document 1 is difficult to visually check the cooling state, such as the presence or absence of freezing, even if the cold-keeping composition contains a dye, and it is at a desired temperature that can be kept cold. There is a problem that the cold insulator is sufficiently cooled until it is difficult to visually check the cooling state.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the cooler which can be visually recognized easily whether a cooling state exists in the target state.

In order to solve the above-mentioned problem, a first aspect of the present invention is a cold-retaining tool comprising a cold-retaining composition containing water, an inorganic salt, a thickener, and a pH indicator, wherein the cold-retaining composition comprises: As the inorganic salt, an acidic inorganic salt whose aqueous solution exhibits acidity and a phosphate, and the acidic inorganic salt and phosphoric acid with respect to the total content of the inorganic salt in the cold-retaining composition The ratio of the total content of the salt is 5 to 100% by mass, and the composition for cold preservation contains, as the acidic inorganic salt, an inorganic salt other than dihydrogen phosphate and dihydrogen phosphate. The pH indicator has a pKa of 4.9 to 8.0, and the composition for cold preservation has a pH (α1) when all components other than phosphate, dihydrogen phosphate and water are removed. , Satisfying the relationship represented by the following formula (i) with respect to the pKa. It is a tool.
pKa of pH indicator ≦ pH (α1) ≦ pKa of pH indicator + 1.8 (i)

In the 1st aspect of this invention, it is preferable that pH of the said composition for cold preservation is 4.6-8.8.
In the first aspect of the present invention, the cold-retaining composition has a pH (α3) of 6.0 to 8.5 when all the components other than the thickener and water are replaced with water. Those are preferred.

  Moreover, the second aspect of the present invention is a cold insulator provided with a cold-retaining composition containing water, an inorganic salt, a thickener and a pH indicator, wherein the cold-retaining composition is used as the inorganic salt, The aqueous solution contains an acidic inorganic salt that exhibits acidity, and monohydrogen phosphate, and in the cold insulation composition, the acidic inorganic salt and monohydrogen phosphate with respect to the total content of the inorganic salt The total content of is 5 to 100% by mass, and in the composition for cold insulation, the ratio of the content of monohydrogen phosphate to the total content of water, the inorganic salt and the thickener is It is 0.2-5.0 mass%, pKa of the said pH indicator is a 4.9-8.0 cold storage tool.

In the 2nd aspect of this invention, it is preferable that pH of the said composition for cold preservation is 4.7-8.0.
In the second aspect of the present invention, the cold-retaining composition has a pH (α3) of 6.0 to 9.1 when all the components other than the thickener and water are replaced with water. Those are preferred.

  Moreover, the third aspect of the present invention is a cold insulator provided with a cold insulation composition containing water, an inorganic salt, a thickener and a pH indicator, wherein the cold insulation composition is used as the inorganic salt, The aqueous solution contains an acidic inorganic salt exhibiting acidity, and in the composition for cold preservation, the ratio of the content of the acidic inorganic salt to the total content of the inorganic salt is 5 to 100% by mass, The cold-retaining composition has a pH (α2) of 7 or less when all the components other than the inorganic salt and water are replaced with water, and the cold-retaining composition comprises the thickener and water. PH (α3) is 7 or more when all other components are replaced with water, and the pH (α2) and pH (α3) are lower than the color change range of the pH indicator. Of the three pH ranges of pH and pH higher than the color change range, It indicates the value of that pH range, a cold tool.

  ADVANTAGE OF THE INVENTION According to this invention, the cooler which can be visually recognized easily whether a cooling state exists in the target state is provided.

<< First Embodiment >>
The cold insulator according to the first embodiment of the present invention is a cold insulator provided with a cold insulating composition containing water, an inorganic salt, a thickener and a pH indicator, wherein the cold insulating composition is the inorganic salt. As the total amount of the acidic inorganic salt and the phosphate with respect to the total content of the inorganic salt in the composition for cold preservation, the acidic inorganic salt whose aqueous solution shows acidity and a phosphate. The content ratio is 5 to 100% by mass, and the composition for cold preservation contains, as the acidic inorganic salt, a dihydrogen phosphate and an inorganic salt other than the dihydrogen phosphate, and the pH The pKa of the indicator is 4.9 to 8.0, and the composition for cold preservation has a pH (α1) obtained when all components other than phosphate, dihydrogen phosphate and water are removed. On the other hand, the relationship represented by the following formula (i) is satisfied.
pKa of pH indicator ≦ pH (α1) ≦ pKa of pH indicator + 1.8 (i)

  Since the color of the cold insulation composition reflecting the presence or absence of color development of the pH indicator greatly changes before and after freezing of the cold insulation composition, the cold insulation device is in a state where the cooling state is the target state (the object is sufficiently It can be easily visually confirmed whether it is in a state where it can be cooled down. And the color of the composition for cold preservation before and after freezing does not mainly reflect the color of components other than pH indicators, such as the said inorganic salt and a thickener.

  Although the composition for cold preservation in 1st Embodiment contains an inorganic salt and a thickener as a component which influences the acidity, as an inorganic salt, dihydrogen phosphate and phosphoric acid which are acidic inorganic salts By selecting a specific combination of inorganic salts other than dihydrogen salts, and phosphates, limiting their contents, and further combining a pH indicator with a pKa in a specific range with respect to these inorganic salts, Depending on the change or the presence or absence of the color development of the pH indicator, a significantly large color change is caused.

<Inorganic salt>
The said inorganic salt in 1st Embodiment functions as one component of a cryogen, and the freezing temperature of the composition for cold preservation is mainly determined by the kind and quantity.
In addition, the inorganic salt does not correspond to the pH indicator, and is a component that precipitates as crystals or amorphous (amorphous) when the composition for cold preservation is frozen, and is involved in the color change of the composition for cold preservation by precipitation. Is.

  The composition for cold preservation in the first embodiment contains, as the inorganic salt, an acidic inorganic salt whose aqueous solution exhibits acidity and a phosphate, and further, as the acidic inorganic salt, dihydrogen phosphate. It contains salts and inorganic salts other than dihydrogen phosphate.

[Acid inorganic salt]
(Dihydrogen phosphate)
In the first embodiment, the dihydrogen phosphate used as the acidic inorganic salt is formed by replacing one hydrogen ion in phosphoric acid (H ₃ PO ₄ ) with a cation, and is non-hydrated. It may be a hydrate.
Examples of the dihydrogen phosphate in the first embodiment include sodium dihydrogen phosphate (NaH ₂ PO ₄ ), potassium dihydrogen phosphate (KH ₂ PO ₄ ), and calcium dihydrogen phosphate (Ca (H ₂ PO). ₄ ) Dihydrogen phosphate metal salts such as ₂ ); dihydrogen phosphate nonmetal salts such as ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ), and the like.

  1 type may be sufficient as the dihydrogen phosphate which the composition for cold preservation in 1st Embodiment contains, and when it is 2 or more types and they are 2 or more types, those combinations and ratios can be selected arbitrarily. .

(Inorganic salts other than dihydrogen phosphate)
In the first embodiment, the inorganic salt other than the dihydrogen phosphate used as the acidic inorganic salt is not particularly limited as long as the aqueous solution exhibits acidity, and may be a non-hydrate. Hydrates may also be used.
Examples of inorganic salts other than the dihydrogen phosphate in the first embodiment include ammonium chloride (NH ₄ Cl), magnesium chloride (MgCl ₂ ), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), and ammonium nitrate (NH ₄ ). NO ₃ ), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), alum (AlK (SO ₄ ) ₂ ), ammonium alum (Al (NH ₄ ) (SO ₄ ) ₂ ), calcium nitrate tetrahydrate (Ca ( NO ₃ ) ₂ · 4H ₂ O), calcium nitrate (Ca (NO ₃ ) ₂ ) and the like, and ammonium chloride and ammonium nitrate are preferable.

  The inorganic salt other than the dihydrogen phosphate contained in the composition for cold preservation in the first embodiment may be only one type, or two or more types, and when two or more types are used, the combination and ratio thereof are as follows: Can be arbitrarily selected.

[Phosphate]
The phosphate in the first embodiment is formed by replacing three hydrogen ions in phosphoric acid (H ₃ PO ₄ ) with a cation, and may be non-hydrated or hydrated. It may be a thing.
The phosphate is usually a basic salt whose aqueous solution shows basicity.

Examples of the phosphate in the first embodiment include trisodium phosphate (Na ₃ PO ₄ ), trisodium phosphate dodecahydrate (Na ₃ PO ₄ · 12H ₂ O), and tripotassium phosphate (K ₃ PO ₄ ) triphosphates such as phosphate; triammonium phosphates such as triammonium phosphate ((NH ₃ ) ₃ PO ₄ ), trisodium phosphate (Na ₃ PO ₄ ), phosphorus Trisodium acid dodecahydrate and tripotassium phosphate (K ₃ PO ₄ ) are preferred.

  Only 1 type may be sufficient as the phosphate which the composition for cold preservation in 1st Embodiment contains, and when it is 2 or more types, when they are 2 or more types, those combinations and ratios can be selected arbitrarily.

[Other inorganic salts]
In addition to the acidic inorganic salt (inorganic salt other than dihydrogen phosphate and dihydrogen phosphate) and phosphate as the inorganic salt, the composition for cold insulation in the first embodiment includes any of these as well. Other inorganic salts not applicable may be contained.
The other inorganic salts may be non-hydrates or hydrates.

  Although the said other inorganic salt in 1st Embodiment is not specifically limited unless the effect of this invention is impaired, For example, the neutral inorganic salt in which the aqueous solution shows neutrality, The phosphate in which the aqueous solution shows basicity And other inorganic salts.

Examples of the neutral inorganic salt include sodium chloride (NaCl), potassium chloride (KCl), calcium chloride (CaCl ₂ ), sodium sulfate (Na ₂ SO ₄ ), potassium sulfate (K ₂ SO ₄ ), and magnesium sulfate. (MgSO ₄ ), sodium nitrate (NaNO ₃ ), potassium nitrate (KNO ₃ ), potassium bromide (KBr), sodium bromide (NaBr), potassium iodide (KI), sodium iodide (NaI), potassium chlorate ( KClO ₃ ), sodium perchlorate (NaClO ₄ ), sodium thiosulfate (Na ₂ S ₂ O ₃ ) and the like.
Among these, the neutral inorganic salt is preferably sodium chloride or potassium chloride.

The basic inorganic salt other than the phosphate is preferably an inorganic salt other than monohydrogen phosphate, such as sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), and hydrogen carbonate. Examples include sodium (NaHCO ₃ ), potassium hydrogen carbonate (KHCO ₃ ), sodium sulfite (Na ₂ SO ₃ ), and borax (Na ₂ B ₄ O ₇ ).
Among these, the basic inorganic salt other than the phosphate is preferably sodium carbonate or potassium carbonate.

  The said other inorganic salt which the composition for cold preservation in 1st Embodiment contains may be only 1 type, 2 or more types, and when they are 2 or more types, those combinations and ratios can be selected arbitrarily. .

In the composition for cold preservation in the first embodiment, the ratio of the total content of the acidic inorganic salt and phosphate to the total content of the inorganic salt is 5 to 100% by mass, and 5.5 to 5.5%. It is preferable that it is 100 mass%. When the said ratio is more than the said lower limit, the composition for cold preservation becomes large in the color change before and behind freezing.
In such a numerical range, as the lower limit of the ratio, for example, 10% by mass, 20% by mass, 30% by mass, 40% by mass, 45% by mass and the like can be selected, but not limited thereto. Further, in such a numerical range, the upper limit value of the ratio can be selected from, for example, 90% by mass, 80% by mass, 70% by mass, 60% by mass, 55% by mass, but is not limited thereto. .

Before freezing in the first embodiment, preferably in the composition for cold preservation at 0 ° C. or higher, the larger the amount of the inorganic salt dissolved, the more the amount dissolved in the total amount of the inorganic salt. It is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and may be 100% by mass (total amount).
Moreover, in the composition for cold preservation after freezing in 1st Embodiment, the said inorganic salt is so preferable that there is much the amount which has precipitated, and the amount which has precipitated among the total amount of the said inorganic salt is 90 mass% or more. It is preferable that it is 95 mass% or more, it is more preferable that it is 98 mass% or more, and 100 mass% (total amount) may be sufficient.

  The total content of the inorganic salt of the composition for cold preservation in the first embodiment is preferably 5 to 35% by mass, more preferably 10 to 30% by mass, and 15 to 25% by mass. Particularly preferred.

<Thickener>
The said thickener in 1st Embodiment is a component which increases the viscosity of the composition for cold preservation, and does not correspond to the said pH indicator. The thickener in the first embodiment is preferably one that does not precipitate when the composition for cold preservation is frozen. In the present specification, “the thickener does not precipitate when the cryogenic composition is frozen” means that the thickener is solidified while being dissolved in water when the cryogenic composition is frozen, It is presumed that the thickener molecules are not solidified and are solidified while surrounded by water molecules, and the thickener molecules are not solidified by aggregation. Guessed.

  Although it does not specifically limit as said thickener in 1st Embodiment, For example, acryl-type polymers (compound which has polyacrylic acid frame | skeleton), such as polyacrylic acid and sodium polyacrylate; Carboxyalkyl, such as carboxymethylcellulose (CMC) Cellulose; guar gum; hydroxyalkyl guar gum such as hydroxypropyl guar gum; pectin; xanthan gum; tamarind gum; carrageenan; alkylene glycol such as propylene glycol.

The thickener in the first embodiment may be at least one selected from the group consisting of acrylic polymer, carboxyalkyl cellulose, xanthan gum, guar gum, hydroxyalkyl guar gum, pectin, tamarind gum, carrageenan and alkylene glycol. preferable.
The thickener is more preferably one or more selected from the group consisting of acrylic polymers, carboxyalkyl cellulose, xanthan gum, guar gum and hydroxyalkyl guar gum.
By using such a thickener, the composition for cold preservation has a large color change before and after freezing and is excellent in handleability.

  Only 1 type may be sufficient as the thickener which the composition for cold preservation in 1st Embodiment contains, and when it is 2 or more types, when they are 2 or more types, those combinations and ratios can be selected arbitrarily.

  In the composition for cold preservation before freezing and after freezing in the first embodiment, the thickening agent is preferable as the amount of the thickening agent is less, and the amount of the thickening agent is 10% by mass or less in the total amount of the thickening agent. It is preferably 5% by mass or less, more preferably 2% by mass or less, and particularly preferably 0% by mass (the total amount is not precipitated).

  In the first embodiment, the content of the thickener in the composition for cold preservation is preferably 0.1 to 10% by mass, more preferably 0.3 to 6% by mass, and 0.6 to 3%. It is particularly preferable that the content is% by mass.

<PH indicator>
The pH indicator (acid-base indicator) in the first embodiment determines the color of the composition for cold preservation by reflecting the presence or absence of color development. The composition for cold preservation changes a color before and after freezing by containing a pH indicator.

The pH indicator in the first embodiment is not particularly limited as long as the pKa is 4.9 to 8.0.
In addition, unless otherwise indicated, pKa of the pH indicator in this embodiment means the value in case a solvent is water and temperature is 25 degreeC.

  The pH indicator has a pH range in which the color change is observed, that is, a color change range. A pH indicator exists in a solution in a dissociated form and an undissociated form, and a dissociation equilibrium is established between them. The dissociated form and the undissociated form have different colors. Then, the equilibrium is remarkably offset in either the dissociated form or the undissociated form, and only one color is seen. In the color change range, the pH indicator is mixed in an amount that can be compared between the dissociated form and the undissociated form, and a mixture of both colors is observed ("Chemical Dictionary Dictionary 39th Edition, 2006 9"). May 15 ", Kyoritsu Publishing Co., Ltd.)).

  Table 1 illustrates the main pH indicators. Table 1 shows the color change area and color change together with the pH indicator. “Color change (low pH → high pH)” in Table 1 means that the pH indicator changes when the pH of the liquid containing the pH indicator changes from a specific value to a higher value. For example, “red → yellow” means that the pH indicator changes the color of the liquid from red to yellow in the process of increasing the pH of the liquid.

  The pH indicator in the first embodiment, for example, preferably has a color change range (pH) in the range of 3.0 to 10.5, more preferably in the range of 4.0 to 9.5. And those within the range of 4.5 to 9.0 are particularly preferred.

  1 type may be sufficient as the pH indicator which the composition for cold preservation in 1st Embodiment contains, and when it is 2 or more types, when they are 2 or more types, those combinations and ratios can be selected arbitrarily. However, it is usually preferable to contain only one kind of pH indicator.

  Although content of the pH indicator of the composition for cold preservation in 1st Embodiment is not specifically limited as long as the target color change of the composition for cold preservation is achieved, It is preferable that it is 1-30 ppm, and is 5-20 ppm. More preferably.

<Other ingredients>
The composition for cold preservation in 1st Embodiment may contain the other component which does not correspond to these in the range which does not impair the effect of this invention other than water, an inorganic salt, a thickener, and a pH indicator. . Examples of the other components include solvents other than water; various known additives such as preservatives and surfactants.
The said other component which the composition for cold preservation in 1st Embodiment contains may be only 1 type, 2 or more types, and when they are 2 or more types, those combinations and ratios can be selected arbitrarily.

(solvent)
The solvent in the first embodiment is preferably one that can dissolve the inorganic salt, thickener, and pH indicator, and examples of such a solvent include alcohol.

Water and the solvent function as one component of a cryogen, and together with the inorganic salt, the freezing temperature of the cryogen composition is determined mainly by the type and amount thereof.
In the composition for cold preservation in the first embodiment, the ratio of the content of the solvent to the total content of water and the solvent is preferably 10% by mass or less, and more preferably 5% by mass or less. 2% by mass or less is particularly preferable.

(Preservative)
Examples of the preservative in the first embodiment include food preservatives, antioxidants, and the like. More specifically, sodium pyrithione, paraben (paraoxybenzoic acid ester), protamine, organic nitrogen sulfur-based compound, and the like. Is mentioned.

  Although content of the antiseptic | preservative of the composition for cold preservation in 1st Embodiment is not specifically limited, It is preferable that it is 0.02-0.5 mass%, and it is 0.04-0.2 mass%. More preferred.

(Surfactant)
Examples of the surfactant in the first embodiment include known ones such as alkyl sulfates such as sodium dodecyl sulfate; alkyl carboxylates such as sodium decanoate; N-alkyl acrylamides such as N-isopropylacrylamide. Polyoxyethylene dialkyl ethers such as polyoxyethylene octyldodecyl ether; polyoxyethylene monoalkyl ethers such as polyoxyethylene lauryl ether; polyoxyethylene monoalkenyl ethers such as polyoxyethylene oleyl ether;

  The composition for cold preservation in 1st Embodiment is the said inorganic salt, increase with respect to the total content of components other than water and the said solvent (The said inorganic salt, a thickener, a pH indicator, and other components other than the said solvent). The ratio of the total content of the adhesive and the pH indicator is preferably 90% by mass or more, more preferably 93% by mass or more, further preferably 96% by mass or more, and 98% by mass or more. It is particularly preferable that it may be 100% by mass. When the ratio of the total content is equal to or higher than the lower limit value, the color of the cold-retaining composition changes more greatly before and after freezing.

In the composition for cold preservation in the first embodiment, the pH (α1) when all the components other than phosphate, dihydrogen phosphate and water are removed is expressed by the following formula (pKa) of the pH indicator: The relationship represented by i) is satisfied.
pKa of pH indicator ≦ pH (α1) ≦ pKa of pH indicator + 1.8 (i)
pH (α1) is a mixed solution (for example, phosphate) obtained by mixing only the same amount of phosphate, dihydrogen phosphate and water as the amount contained in the composition for cold preservation in the first embodiment. And a pH of the aqueous solution containing dihydrogen phosphate), which is an index of the acidity of the mixture of phosphate and dihydrogen phosphate used in the cold-retaining composition.

  The pH (α1) is preferably the pH at which the pH indicator is dissolved in the cold-retaining composition, and more preferably the pH when the temperature of the mixed solution is 25 ° C.

  The pH (α1) preferably further satisfies 5.0 to 10.6, more preferably 5.3 to 10.3, after satisfying the relationship of the formula (i). 6 to 10.0 is particularly preferable.

The pH of the composition for cold preservation in the first embodiment is preferably 4.6 to 8.8, more preferably 4.9 to 8.5, and 5.1 to 8.3. Is particularly preferred.
The composition for cold preservation in the first embodiment preferably exhibits a pH in the numerical range at a temperature at which the pH indicator is dissolved in the composition for cold preservation, and the temperature of the composition for cold insulation is 25 ° C. Sometimes it is more preferred to exhibit a pH in the numerical range.
In addition, in this embodiment, description with mere "pH" about the composition for cold preservation shall mean the pH of the composition for cold preservation itself unless there is particular notice.

The composition for cold preservation in the first embodiment preferably has a pH (α2) of 4.4 to 8.7 when all the components other than the inorganic salt and water are replaced with water. More preferably, it is -8.2.
The pH (α2) corresponds to the pH of an inorganic salt-containing water (for example, an inorganic salt aqueous solution) containing only the inorganic salt at the same content (mass%) as the content (mass%) in the composition for cold preservation. And it becomes a parameter | index of the acidity of the inorganic salt used with the said composition for cold preservation.
The pH (α2) is preferably the pH at the temperature at which the pH indicator is dissolved in the cold-retaining composition, and more preferably the pH when the inorganic salt-containing water is 25 ° C.

The composition for cold preservation in the first embodiment preferably has a pH (α3) of 6.0 to 8.5 when all the components other than the thickener and water are replaced with water. More preferably, it is 0-8.3, for example, 6.0-8.0 may be sufficient and 6.5-7.5 may be sufficient.
pH (α3) is the same as the content (mass%) in the cold insulation composition (mass%) of the thickener-containing water (eg, thickener aqueous solution) containing only the thickener. It corresponds to pH and serves as an index of the acidity of the thickener used in the cold-retaining composition.
The pH (α3) is preferably the pH at which the pH indicator is dissolved in the cold-retaining composition, and more preferably the pH when the thickener-containing water is 25 ° C. .

The composition for cold preservation in 1st Embodiment is obtained by mix | blending water, the said inorganic salt, a thickener, a pH indicator, and the said other component as needed.
The blending method of each component is not particularly limited, and can be arbitrarily adjusted so that each component is uniformly dissolved or dispersed at a temperature higher than the freezing temperature of the composition for cold preservation.
For example, when blending each component, all the components may be added and then mixed, or some components may be mixed while being added sequentially, and all components may be mixed while being added sequentially. May be.
The mixing method is not particularly limited, a method of mixing by rotating a stirrer or a stirring blade; a method of mixing using a mixer, a three-roller, a kneader, a bead mill or the like; a method of mixing by adding ultrasonic waves, etc. What is necessary is just to select suitably from a well-known method.

  The cold insulation tool according to the first embodiment of the present invention is provided with the cold insulation composition. For example, the cold insulation composition is held by a holding means such as a container or bag that can enclose a liquid material. It is composed by doing.

  The material of the holding means is not particularly limited as long as it is transparent to the extent that the color change (discoloration) of the held cooling composition can be visually recognized. Preferred examples include polyethylene and polypropylene. Polyolefins such as polyamide; synthetic resins such as polyamide; polyester and the like. Examples of polyethylene include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE).

The material and size of the holding means may be selected in consideration of, for example, the shape of the holding means, the amount of the cold-retaining composition held, or how the color of the cold-retaining composition changes before and after freezing.
For example, in the case of a bag-shaped holding means, an example of a preferable material of the holding means is low density polyethylene. In the case of a container-shaped holding means, an example of a preferable material for the holding means is high-density polyethylene.
For example, the bag-shaped holding means is preferable when it is used as a small one, that is, when the amount of the cold-retaining composition is relatively small. The container-like holding means is preferable when it is used as a large one, that is, when the amount of the cold-retaining composition is relatively large.
However, the method for selecting the material and size of the holding means shown here is merely an example.

  The material of the holding means is preferably polyolefin in terms of excellent low temperature brittleness resistance, water resistance and chemical resistance, and is high density polyethylene in terms of easy molding and high strength. It is more preferable.

  The thickness of the flat part such as a film or sheet in the holding means is not particularly limited, but is preferably 5 to 200 μm.

The flat part may be composed of a single layer or may be composed of two or more layers. When the flat portion is composed of a plurality of layers, the plurality of layers may be the same as or different from each other. That is, all the layers may be the same, all the layers may be different, or only some of the layers may be the same. And when several layers differ from each other, the combination of these several layers is not specifically limited. Here, the plurality of layers being different from each other means that at least one of the material and the thickness of each layer is different from each other.
When the flat part is composed of a plurality of layers, the total thickness of each layer is preferably the thickness of the preferred flat part.

The composition for cold preservation in the first embodiment changes color greatly before and after freezing, and thus the presence or absence of freezing can be easily visually confirmed. And this color change of the composition for cold insulation can be visually recognized from the outside of the cold insulator, and thereby, it can be easily visually confirmed whether or not the cold insulator is sufficiently cooled to a desired temperature. ing.
In addition, since the effect of the cold-retaining composition is not impaired even when cooling and heating are repeated, such as repeated freezing and thawing, the cold-retaining tool provided with the composition is suitable for repeated use. is there.

<< Second Embodiment >>
The cold insulation device according to the second embodiment of the present invention is a cold insulation device provided with a cold insulation composition containing water, an inorganic salt, a thickener, and a pH indicator, wherein the cold insulation composition is the inorganic salt. The aqueous solution contains an acidic inorganic salt that exhibits acidity and monohydrogen phosphate, and in the composition for cold preservation, the acidic inorganic salt and monobasic phosphate with respect to the total content of the inorganic salt The ratio of the total content of hydrogen salt is 5 to 100% by mass, and the ratio of the content of monohydrogen phosphate to the total content of water, the inorganic salt and the thickener in the composition for cold preservation Is 0.2 to 5.0% by mass, and the pH indicator has a pKa of 4.9 to 8.0.

  Since the color of the cold insulation composition reflecting the presence or absence of color development of the pH indicator greatly changes before and after freezing of the cold insulation composition, the cold insulation device is in a state where the cooling state is the target state (the object is sufficiently It can be easily visually confirmed whether it is in a state where it can be cooled down. And the color of the composition for cold preservation before and after freezing does not mainly reflect the color of components other than pH indicators, such as the said inorganic salt and a thickener.

  Although the composition for cold preservation in 2nd Embodiment contains an inorganic salt and a thickener as a component which affects the acidity, as an inorganic salt, the specific combination of acidic inorganic salt and monohydrogen phosphate salt The content of these is limited, and for monohydrogen phosphate, the ratio of the content to the total content of water, inorganic salt and thickener is also limited. By combining a pH indicator having a pKa in a specific range with respect to the agent, a remarkably large color change is caused depending on the color change or presence or absence of the pH indicator.

<Inorganic salt>
The said inorganic salt in 2nd Embodiment functions as one component of a cryoprotectant, and the freezing temperature of the composition for cold preservation is mainly determined by the kind and quantity.
In addition, the inorganic salt does not correspond to the pH indicator, and is a component that precipitates as crystals or amorphous (amorphous) when the composition for cold preservation is frozen, and is involved in the color change of the composition for cold preservation by precipitation. Is.

  The said composition for cold preservation in 2nd Embodiment contains the acidic inorganic salt in which the aqueous solution shows acidity, and monohydrogen phosphate as said inorganic salt.

[Acid inorganic salt]
The acidic inorganic salt in the second embodiment is not particularly limited and can be appropriately selected depending on the purpose, and may be a non-hydrate or a hydrate.
As an acidic inorganic salt in 2nd Embodiment, the same thing as the said acidic inorganic salt in 1st Embodiment, ie, inorganic salts other than dihydrogen phosphate and dihydrogen phosphate, is mentioned, for example. .

  The acidic inorganic salt contained in the composition for cold insulation in the second embodiment may be only one kind, or may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof can be arbitrarily selected. .

[Monophosphate]
The monohydrogen phosphate in the second embodiment is obtained by replacing two hydrogen ions in phosphoric acid (H ₃ PO ₄ ) with a cation, and may be a non-hydrate, Hydrates may also be used.
The monohydrogen phosphate is generally a basic salt whose aqueous solution shows basicity.

Examples of the monohydrogen phosphate in the second embodiment include phosphorus such as disodium hydrogen phosphate (Na ₂ HPO ₄ ), dipotassium hydrogen phosphate (K ₂ HPO ₄ ), and calcium hydrogen phosphate (CaHPO ₄ ). Examples thereof include metal monohydrogen phosphate; non-metal monohydrogen phosphate such as diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ).

  1 type of phosphoric acid monohydrogen salt which the composition for cold preservation in 2nd Embodiment contains may be one, 2 or more types, and when they are 2 or more types, those combinations and ratios can be selected arbitrarily. .

[Other inorganic salts]
The composition for cold preservation in 2nd Embodiment may contain the other inorganic salt which does not correspond to any of these other than the said acidic inorganic salt and phosphoric acid monohydrogen salt as said inorganic salt.
The other inorganic salts may be non-hydrates or hydrates.

  Although the said other inorganic salt in 2nd Embodiment is not specifically limited unless the effect of this invention is impaired, For example, the neutral inorganic salt in which the aqueous solution shows neutrality, The phosphoric acid one in which the aqueous solution shows basicity Examples include inorganic salts other than hydrogen salts.

  As said neutral inorganic salt, the same thing as the said neutral inorganic salt in 1st Embodiment is mentioned, for example, It is preferable that they are sodium chloride, potassium chloride, or sodium sulfate.

  The basic inorganic salt other than the phosphate monobasic salt is preferably an inorganic salt other than a phosphate, and for example, the same basic inorganic salt other than the phosphate in the first embodiment may be used. And is preferably sodium carbonate or potassium carbonate.

  The said other inorganic salt which the composition for cold preservation in 2nd Embodiment contains may be only 1 type, 2 or more types, and when they are 2 or more types, those combinations and ratios can be selected arbitrarily. .

  A preferable example of the cold-retaining composition in the second embodiment includes a dihydrogen phosphate that is the acidic inorganic salt and a neutral inorganic salt. Such a cold-retaining composition has a shorter time required for completion of the color change before and after freezing and has more preferable properties.

  When the composition for cold preservation in 2nd Embodiment contains a phosphoric acid dihydrogen salt and a neutral inorganic salt, it is preferable that the said neutral inorganic salt is sodium chloride or potassium chloride. By using such a neutral inorganic salt together, the color change of the composition for cold preservation in the second embodiment is completed in a shorter time before and after freezing.

  When the composition for cold preservation in 2nd Embodiment contains phosphoric acid dihydrogen salt and neutral inorganic salt, the ratio of content of neutral inorganic salt with respect to the total content of inorganic salt is 40-60. It is preferable that it is mass%, It is more preferable that it is 43-57 mass%, It is especially preferable that it is 46-54 mass%. When the ratio is in such a range, the composition for cold preservation in the second embodiment completes a color change in a shorter time and undergoes a greater color change before and after freezing.

When the composition for cold preservation in 2nd Embodiment contains phosphoric acid dihydrogen salt and neutral inorganic salt, content (mass) of dihydrogen phosphate with respect to content (mass) of monohydrogen phosphate ) Ratio ([content of dihydrogen phosphate in the composition for cold preservation (mass)] / [content of monohydrogen phosphate in the composition for cold insulation (mass)]) is 0.04 to 2 Preferably, it is 0.04 to 1.6, more preferably 0.04 to 1.4. When the ratio is in such a range, the color change of the composition for cold insulation in the second embodiment is completed in a shorter time before and after freezing.
Furthermore, since the color-retaining composition in the second embodiment undergoes a greater color change before and after freezing, the ratio is preferably 0.04 to 1.2, and 0.07 to 0.8. It is more preferable that it is 0.1-0.6.

In the composition for cold preservation in the second embodiment, the ratio of the total content of the acidic inorganic salt and monohydrogen phosphate to the total content of the inorganic salt is 5 to 100% by mass. It is preferably 5 to 100% by mass, and more preferably 6 to 100% by mass. When the said ratio is more than the said lower limit, the composition for cold preservation becomes large in the color change before and behind freezing.
In such a numerical range, as the lower limit of the ratio, for example, 10% by mass, 20% by mass, 30% by mass, 40% by mass, 45% by mass and the like can be selected, but not limited thereto. Further, in such a numerical range, as the upper limit value of the ratio, for example, 90% by mass, 80% by mass, 75% by mass, 70% by mass, 65% by mass and the like can be selected, but not limited thereto. .

Before freezing in the second embodiment, preferably in the composition for cold preservation at 0 ° C. or higher, the amount of dissolved inorganic salt is preferably as the amount dissolved, and the amount dissolved in the total amount of the inorganic salt is It is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and may be 100% by mass (total amount).
Moreover, in the composition for cold preservation after freezing in 2nd Embodiment, the said inorganic salt is so preferable that there is much the amount which has precipitated, and the amount which has precipitated among the total amount of the said inorganic salt is 90 mass% or more. It is preferable that it is 95 mass% or more, it is more preferable that it is 98 mass% or more, and 100 mass% (total amount) may be sufficient.

  The total content of the inorganic salt of the composition for cold insulation in the second embodiment is preferably 5 to 35% by mass, more preferably 5 to 30% by mass, and 10 to 30% by mass. More preferably, it may be, for example, 15 to 25% by mass.

<Thickener>
The said thickener in 2nd Embodiment is a component which increases the viscosity of the composition for cold preservation, and does not correspond to the said pH indicator. The thickener in the second embodiment is preferably one that does not precipitate when the composition for cold preservation is frozen. In the present specification, “the thickener does not precipitate when the composition for cold preservation is frozen” is as described above in the first embodiment.

As said thickener in 2nd Embodiment, the same thing as the thickener in 1st Embodiment is mentioned, for example.
As in the case of the first embodiment, the thickener in the second embodiment is selected from the group consisting of acrylic polymer, carboxyalkyl cellulose, xanthan gum, guar gum, hydroxyalkyl guar gum, pectin, tamarind gum, carrageenan and alkylene glycol. It is preferable that it is 1 or more types selected.
The thickener is more preferably one or more selected from the group consisting of acrylic polymers, carboxyalkyl cellulose, xanthan gum, guar gum and hydroxyalkyl guar gum.
By using such a thickener, the composition for cold preservation has a large color change before and after freezing and is excellent in handleability.

  Only 1 type may be sufficient as the thickener which the composition for cold preservation in 2nd Embodiment contains, and when it is 2 or more types, when they are 2 or more types, those combinations and ratios can be selected arbitrarily.

  In the composition for cold preservation before freezing and after freezing in the second embodiment, the thickener is preferably as small as the amount of the thickener deposited, and the amount of the thickener deposited is 10% by mass or less. It is preferably 5% by mass or less, more preferably 2% by mass or less, and particularly preferably 0% by mass (the total amount is not precipitated).

  In the second embodiment, the content of the thickener in the composition for cold insulation is preferably 0.1 to 10% by mass, more preferably 0.3 to 6% by mass, and 0.6 to 3%. It is particularly preferable that the content is% by mass.

  In the composition for cold preservation in the second embodiment, the ratio of the content of monohydrogen phosphate to the total content of water, the inorganic salt and the thickener is 0.2 to 5.0% by mass. 0.23 to 4.9% by mass, and more preferably 0.26 to 4.8% by mass. When the ratio is in such a range, the color change before and after freezing increases in the composition for cold preservation.

<PH indicator>
The pH indicator (acid-base indicator) in the second embodiment determines the color of the composition for cold preservation by reflecting the presence or absence of color development. The composition for cold preservation changes a color before and after freezing by containing a pH indicator.

The pH indicator in the second embodiment is not particularly limited as long as the pKa is 4.9 to 8.0.
In addition, unless otherwise indicated, pKa of the pH indicator in this embodiment means the value in case a solvent is water and temperature is 25 degreeC.
As said pH indicator in 2nd Embodiment, the same thing as the pH indicator in 1st Embodiment is mentioned, for example.

  The pH indicator in the second embodiment, for example, preferably has a color change range (pH) in the range of 3.0 to 9.0, more preferably in the range of 4.0 to 8.5. And those within the range of 4.5 to 8.0 are particularly preferred.

  Only 1 type may be sufficient as the pH indicator which the composition for cold preservation in 2nd Embodiment contains, and when it is 2 or more types, those combinations and ratios can be selected arbitrarily. However, it is usually preferable to contain only one kind of pH indicator.

  Although content of the pH indicator of the composition for cold preservation in 2nd Embodiment is not specifically limited as long as the target color change of the composition for cold preservation is achieved, It is preferable that it is 1-30 ppm, and is 5-20 ppm. More preferably.

<Other ingredients>
The composition for cold preservation in 2nd Embodiment may contain the other component which does not correspond to these in the range which does not impair the effect of this invention other than water, an inorganic salt, a thickener, and a pH indicator. . Examples of the other components include the same solvents other than water as in the first embodiment; various known additives such as preservatives and surfactants.
The said other component which the composition for cold preservation in 2nd Embodiment contains may be only 1 type, 2 or more types, and when they are 2 or more types, those combinations and ratios can be selected arbitrarily.

  Content of the said other component of the composition for cold preservation in 2nd Embodiment is the same as content of the other component of the composition for cold preservation in 1st Embodiment.

For example, in the composition for cold preservation in the second embodiment, the ratio of the content of the solvent to the total content of water and the solvent is preferably 10% by mass or less, and preferably 5% by mass or less. More preferred is 2% by mass or less.
Further, the content of the preservative in the composition for cold preservation in the second embodiment is not particularly limited, but is preferably 0.02 to 0.5% by mass, and 0.04 to 0.2% by mass. It is more preferable.
The composition for cold preservation in 2nd Embodiment is the said inorganic salt and increase with respect to the total content of components other than water and the said solvent (The said inorganic salt, a thickener, a pH indicator, and other components other than the said solvent). The ratio of the total content of the adhesive and the pH indicator is preferably 90% by mass or more, more preferably 93% by mass or more, further preferably 96% by mass or more, and 98% by mass or more. It is particularly preferable that it may be 100% by mass. When the ratio of the total content is equal to or higher than the lower limit value, the color of the cold-retaining composition changes more greatly before and after freezing.

The pH of the cold-retaining composition in the second embodiment is preferably 4.7 to 8.0, more preferably 5.0 to 7.7, and 5.2 to 7.5. Is particularly preferred.
It is preferable that the composition for cold preservation in 2nd Embodiment shows pH of the said numerical range at the temperature which the pH indicator melt | dissolves in the said composition for cold preservation, and the temperature of the said composition for cold preservation is 25 degreeC. Sometimes it is more preferred to exhibit a pH in the numerical range.
In addition, in this embodiment, description with mere "pH" about the composition for cold preservation shall mean the pH of the composition for cold preservation itself unless there is particular notice.

The composition for cold preservation in the second embodiment preferably has a pH (α2) of 4.7 to 8.0 when all the components other than the inorganic salt and water are replaced with water. More preferably, it is -7.5.
The pH (α2) corresponds to the pH of an inorganic salt-containing water (for example, an inorganic salt aqueous solution) containing only the inorganic salt at the same content (mass%) as the content (mass%) in the composition for cold preservation. And it becomes a parameter | index of the acidity of the inorganic salt used with the said composition for cold preservation.
The pH (α2) is preferably the pH at the temperature at which the pH indicator is dissolved in the cold-retaining composition, and more preferably the pH when the inorganic salt-containing water is 25 ° C.

The composition for cold preservation in the second embodiment preferably has a pH (α3) of 6.0 to 9.1 when all the components other than the thickener and water are replaced with water. More preferably, it is 5-8.6.
pH (α3) is the same as the content (mass%) in the cold insulation composition (mass%) of the thickener-containing water (eg, thickener aqueous solution) containing only the thickener. It corresponds to pH and serves as an index of the acidity of the thickener used in the cold-retaining composition.
The pH (α3) is preferably the pH at which the pH indicator is dissolved in the cold-retaining composition, and more preferably the pH when the thickener-containing water is 25 ° C. .

  The composition for cold preservation in 2nd Embodiment is obtained by the same method as the composition for cold insulation in the above-mentioned 1st Embodiment except the compounding component being different.

The cold insulation tool according to the second embodiment of the present invention includes the cold insulation composition, and has the same configuration as the cold insulation tool according to the first embodiment except that the cold insulation composition is different. can do.
The cold insulator according to the second embodiment of the present invention is obtained by the same method as the cold insulator according to the first embodiment described above, except that the cold insulation composition is used.

The composition for cold preservation in the second embodiment changes greatly in color before and after freezing, and thus the presence or absence of freezing can be easily visually confirmed. And this color change of the composition for cold insulation can be visually recognized from the outside of the cold insulator, and thereby, it can be easily visually confirmed whether or not the cold insulator is sufficiently cooled to a desired temperature. ing.
In addition, since the effect of the cold-retaining composition is not impaired even when cooling and heating are repeated, such as repeated freezing and thawing, the cold-retaining tool provided with the composition is suitable for repeated use. is there.

<< Third Embodiment >>
The cold insulation tool according to the third embodiment of the present invention is a cold insulation tool provided with a cold insulation composition containing water, an inorganic salt, a thickener, and a pH indicator, wherein the cold insulation composition is the inorganic salt. As the aqueous solution contains an acidic inorganic salt exhibiting acidity, the ratio of the content of the acidic inorganic salt to the total content of the inorganic salt in the composition for cold preservation is 5 to 100% by mass. Yes, the cold-retaining composition has a pH (α2) of 7 or less when all the components other than the inorganic salt and water are replaced with water, and the cold-retaining composition is the thickener PH (α3) when all components other than water and water are replaced with water is 7 or more, and pH (α2) and pH (α3) are lower than the color change range of the pH indicator, discoloration Of the three pH ranges, the pH of the range and the pH higher than the color change range, Shows the different values of pH range are.

  Since the color of the cold insulation composition reflecting the presence or absence of color development of the pH indicator greatly changes before and after freezing of the cold insulation composition, the cold insulation device is in a state where the cooling state is the target state (the object is sufficiently It can be easily visually confirmed whether it is in a state where it can be cooled down. And the color of the composition for cold preservation before and after freezing does not mainly reflect the color of components other than pH indicators, such as the said inorganic salt and a thickener.

  Although the composition for cold preservation in 3rd Embodiment contains an inorganic salt and a thickener as a component which affects the acidity, an acidic inorganic salt is selected as an inorganic salt, the content is limited, By limiting the acidity of inorganic salts and thickeners, and combining these inorganic salts and thickeners with a pH indicator having a suitable color change range, it depends on the change or presence of color development of the pH indicator. Thus, a remarkably large color change is caused.

<Inorganic salt>
The said inorganic salt in 3rd Embodiment functions as one component of a cryoprotectant, and the freezing temperature of the composition for cold preservation is mainly determined by the kind and quantity.
In addition, the inorganic salt does not correspond to the pH indicator, and is a component that precipitates as crystals or amorphous (amorphous) when the composition for cold preservation is frozen, and is involved in the color change of the composition for cold preservation by precipitation. Is.

  The said composition for cold preservation in 3rd Embodiment contains the acidic inorganic salt in which the aqueous solution shows acidity as said inorganic salt.

[Acid inorganic salt]
The acidic inorganic salt in the third embodiment is not particularly limited and can be appropriately selected depending on the purpose, and may be a non-hydrate or a hydrate.
Preferable acidic inorganic salts in the third embodiment are, for example, the same inorganic salts other than dihydrogen phosphate in the first embodiment, that is, ammonium chloride (NH ₄ Cl), magnesium chloride (MgCl ₂ ). ), Ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), ammonium nitrate (NH ₄ NO ₃ ), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), alum (AlK (SO ₄ ) ₂ ), ammonium alum (Al (NH ₄₎ ) (SO ₄ ) ₂ ), calcium nitrate tetrahydrate (Ca (NO ₃ ) ₂ .4H ₂ O), calcium nitrate (Ca (NO ₃ ) ₂ ) and the like, and ammonium chloride is preferred.

  The acidic inorganic salt contained in the composition for cold preservation in the third embodiment may be only one kind, may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof can be arbitrarily selected. .

[Other inorganic salts]
The composition for cold preservation in 3rd Embodiment may contain other inorganic salt other than the said acidic inorganic salt as said inorganic salt.
The other inorganic salts may be non-hydrates or hydrates.

  The other inorganic salt in the third embodiment is not particularly limited as long as the effects of the present invention are not impaired. For example, the neutral inorganic salt whose aqueous solution shows neutrality, and the basic salt whose aqueous solution shows basicity. An inorganic salt etc. are mentioned.

  As said neutral inorganic salt, the same thing as the said neutral inorganic salt in 1st Embodiment is mentioned, for example, It is preferable that it is sodium chloride or potassium chloride.

  The basic inorganic salt is preferably an inorganic salt other than phosphate and monohydrogen phosphate, and examples thereof include the same basic inorganic salts other than the phosphate in the first embodiment. And is preferably sodium carbonate or potassium carbonate.

  The said other inorganic salt which the composition for cold preservation in 3rd Embodiment contains may be only 1 type, 2 or more types, and when they are 2 or more types, those combinations and ratios can be selected arbitrarily. .

In the composition for cold preservation in the third embodiment, the ratio of the content of the acidic inorganic salt to the total content of the inorganic salt is 5 to 100% by mass, for example, 20 to 80% by mass, 40 Although it can be set to -60 mass% etc., it is not limited to these.
In such a numerical range, as the lower limit of the ratio, in addition to 20% by mass and 40% by mass, for example, 10% by mass, 30% by mass, 45% by mass, etc. can be selected. It is not limited to. Further, in such a numerical range, as the upper limit value of the ratio, for example, 90% by mass, 70% by mass, 55% by mass and the like can be selected in addition to the above 80% by mass and 60% by mass. However, it is not limited to these.

Before freezing in the third embodiment, preferably in the composition for cold preservation at 0 ° C. or higher, the larger the amount of the inorganic salt dissolved, the more the amount dissolved in the total amount of the inorganic salt. It is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and may be 100% by mass (total amount).
Moreover, in the composition for cold preservation after freezing in 3rd Embodiment, the said inorganic salt is so preferable that there is much the amount which has precipitated, and the amount which has precipitated among the total amount of the said inorganic salt is 90 mass% or more. It is preferable that it is 95 mass% or more, it is more preferable that it is 98 mass% or more, and 100 mass% (total amount) may be sufficient.

  The total content of the inorganic salt of the composition for cold preservation in the third embodiment is preferably 5 to 35% by mass, more preferably 10 to 30% by mass, and 15 to 25% by mass. Particularly preferred.

<Thickener>
The thickener in the third embodiment is a component that increases the viscosity of the cold-retaining composition and does not correspond to the pH indicator. The thickener in the third embodiment is preferably one that does not precipitate when the composition for cold preservation is frozen. In the present specification, “the thickener does not precipitate when the composition for cold preservation is frozen” is as described above in the first embodiment.

As said thickener in 3rd Embodiment, the same thing as the thickener in 1st Embodiment is mentioned, for example.
As in the case of the first embodiment, the thickener in the third embodiment is selected from the group consisting of acrylic polymer, carboxyalkyl cellulose, xanthan gum, guar gum, hydroxyalkyl guar gum, pectin, tamarind gum, carrageenan and alkylene glycol. It is preferable that it is 1 or more types selected.
The thickener is more preferably one or more selected from the group consisting of acrylic polymers, carboxyalkyl cellulose, xanthan gum, guar gum and hydroxyalkyl guar gum.
By using such a thickener, the composition for cold preservation has a large color change before and after freezing and is excellent in handleability.

  Only 1 type may be sufficient as the thickener which the composition for cold preservation in 3rd Embodiment contains, and when it is 2 or more types, when they are 2 or more types, those combinations and ratios can be selected arbitrarily.

  In the composition for cold preservation before freezing and after freezing in the third embodiment, the thickening agent is more preferable as the amount thereof is precipitated, and the amount precipitated is 10% by mass or less of the total amount of the thickener. It is preferably 5% by mass or less, more preferably 2% by mass or less, and particularly preferably 0% by mass (the total amount is not precipitated).

  In the third embodiment, the content of the thickener in the composition for cold insulation is preferably 0.1 to 10% by mass, more preferably 0.3 to 6% by mass, and 0.6 to 3%. It is particularly preferable that the content is% by mass.

<PH indicator>
The pH indicator (acid-base indicator) in the third embodiment determines the color of the cold-retaining composition by reflecting the presence or absence of color development. The composition for cold preservation changes a color before and after freezing by containing a pH indicator.

Although the said pH indicator in 3rd Embodiment is not specifically limited, The thing whose pKa is 4.0-7.5 is preferable.
In addition, unless otherwise indicated, pKa of the pH indicator in this embodiment means the value in case a solvent is water and temperature is 25 degreeC.
As said pH indicator in 3rd Embodiment, the same thing as the pH indicator in 1st Embodiment is mentioned, for example.

  The pH indicator in the third embodiment, for example, preferably has a color change range (pH) in the range of 3.0 to 10.5, preferably in the range of 3.3 to 9.5, Those within the range of 3.5 to 9.0 are particularly preferred.

  Only 1 type may be sufficient as the pH indicator which the composition for cold preservation in 3rd Embodiment contains, and when it is 2 or more types, those combinations and ratios can be selected arbitrarily. However, it is usually preferable to contain only one kind of pH indicator.

  Although content of the pH indicator of the composition for cold preservation in 3rd Embodiment is not specifically limited as long as the target color change of the composition for cold preservation is achieved, It is preferable that it is 1-30 ppm, and is 5-20 ppm. More preferably.

<Other ingredients>
The composition for cold preservation in 3rd Embodiment may contain the other component which does not correspond to these in the range which does not impair the effect of this invention other than water, an inorganic salt, a thickener, and a pH indicator. . Examples of the other components include the same solvents other than water as in the first embodiment; various known additives such as preservatives and surfactants.
The said other component which the composition for cold preservation in 3rd Embodiment contains may be only 1 type, 2 or more types, and when they are 2 or more types, those combinations and ratios can be selected arbitrarily.

  Content of the said other component of the composition for cold preservation in 3rd Embodiment is the same as content of the other component of the composition for cold preservation in 1st Embodiment.

For example, in the composition for cold preservation in the third embodiment, the ratio of the content of the solvent to the total content of water and the solvent is preferably 10% by mass or less, and preferably 5% by mass or less. More preferred is 2% by mass or less.
Moreover, the content of the preservative in the composition for cold preservation in the third embodiment is not particularly limited, but is preferably 0.02 to 0.5% by mass, and 0.04 to 0.2% by mass. It is more preferable.
The composition for cold preservation in the third embodiment includes the inorganic salt, the increase in the total content of components other than water and the solvent (the inorganic salt, the thickener, the pH indicator, and other components other than the solvent). The ratio of the total content of the adhesive and the pH indicator is preferably 90% by mass or more, more preferably 93% by mass or more, further preferably 96% by mass or more, and 98% by mass or more. It is particularly preferable that it may be 100% by mass. When the ratio of the total content is equal to or higher than the lower limit value, the color of the cold-retaining composition changes more greatly before and after freezing.

The composition for cold preservation in the third embodiment has a pH (α2) of 7 or less when all the components other than the inorganic salt and water are replaced with water.
The pH (α2) corresponds to the pH of an inorganic salt-containing water (for example, an inorganic salt aqueous solution) containing only the inorganic salt at the same content (mass%) as the content (mass%) in the composition for cold preservation. And it becomes a parameter | index of the acidity of the inorganic salt used with the said composition for cold preservation.
The pH (α2) is preferably from 3.5 to 7.0, more preferably from 4.0 to 6.6, and particularly preferably from 4.5 to 6.3.

  The pH (α2) is preferably the pH at the temperature at which the pH indicator is dissolved in the cold-retaining composition, and more preferably the pH when the inorganic salt-containing water is 25 ° C.

The composition for cold preservation in the third embodiment has a pH (α3) of 7 or more when all the components other than the thickener and water are replaced with water.
pH (α3) is the same as the content (mass%) in the cold insulation composition (mass%) of the thickener-containing water (eg, thickener aqueous solution) containing only the thickener. It corresponds to pH and serves as an index of the acidity of the thickener used in the cold-retaining composition.
The pH (α3) is preferably 7.0 to 9.5, more preferably 7.0 to 9.0, and particularly preferably 7.0 to 8.5.

  The pH (α3) is preferably the pH at which the pH indicator is dissolved in the cold-retaining composition, and more preferably the pH when the thickener-containing water is 25 ° C. .

  The composition for cold preservation in the third embodiment has three pH ranges in which pH (α2) and pH (α3) are lower than the color change range of the pH indicator, the pH of the color change range, and the pH higher than the color change range. Among them, values in different pH ranges are shown.

The pH of the composition for cold preservation in the third embodiment is preferably 4.1 to 7.4, more preferably 4.4 to 7.1, and 4.6 to 6.9. Is particularly preferred.
The cold-retaining composition in the third embodiment preferably exhibits a pH in the numerical range at a temperature at which the pH indicator is dissolved in the cold-retaining composition, and the temperature of the cold-retaining composition is 25 ° C. Sometimes it is more preferred to exhibit a pH in the numerical range.
In addition, in this embodiment, description with mere "pH" about the composition for cold preservation shall mean the pH of the composition for cold preservation itself unless there is particular notice.

  The composition for cold preservation in the third embodiment is obtained by the same method as the composition for cold insulation in the first embodiment described above, except that the blending components are different.

The cold insulation tool according to the third embodiment of the present invention is provided with the cold insulation composition, and has the same configuration as the cold insulation tool according to the first embodiment except that the cold insulation composition is different. can do.
The cold insulator according to the third embodiment of the present invention is obtained by the same method as the cold insulator according to the first embodiment described above, except that the cold insulating composition is used.

The composition for cold preservation in the third embodiment largely changes color before and after freezing, and thus the presence or absence of freezing can be easily visually confirmed. And this color change of the composition for cold insulation can be visually recognized from the outside of the cold insulator, and thereby, it can be easily visually confirmed whether or not the cold insulator is sufficiently cooled to a desired temperature. ing.
In addition, since the effect of the cold-retaining composition is not impaired even when cooling and heating are repeated, such as repeated freezing and thawing, the cold-retaining tool provided with the composition is suitable for repeated use. is there.

  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. In the following, the unit “ppm” of the content (blending amount, concentration) of the pH indicator is based on the mass ratio.

The raw materials used in the examples and comparative examples are shown below.
(Thickener)
HPG1 (hydroxypropyl guar gum): “Meipro HPG8111” manufactured by Sankisha
・ CMC (Carboxymethylcellulose): “Serogen” manufactured by Daiichi Kogyo Seiyaku
CVP (carboxy vinyl polymer): “Reogic 270” manufactured by Toa Gosei Co., Ltd.
(PH indicator)
・ BCP: Bromocresol purple (Wako Pure Chemical Industries, Ltd.)
・ PR: Phenol red (manufactured by Wako Pure Chemical Industries)
・ BTB: Bromothymol Blue (manufactured by Wako Pure Chemical Industries, Ltd.)
・ MR: Methyl Red (manufactured by Wako Pure Chemical Industries)
・ BCG: Bromocresol Green (Wako Pure Chemical Industries, Ltd.)
(Preservative)
"Sodium Omagine" manufactured by Sanai Oil Co., Ltd.

[Example 1]
<Manufacture of composition for cold preservation and cold insulation tool (first embodiment)>
Under room temperature (20-25 ° C.), BCP was added and dissolved in water (79.16 parts by mass), then ammonium chloride (9.72 parts by mass), potassium chloride (9.72 parts by mass), Trisodium phosphate dodecahydrate (0.15 parts by mass) and ammonium dihydrogen phosphate (0.10 parts by mass) were added and dissolved, and then HPG1 (1.10 parts by mass) was added. The mixture was stirred for 1 hour at room temperature and dissolved, and after confirming that the obtained liquid was sufficiently thickened, an antiseptic (0.05 parts by mass) was added, The composition for cold preservation was obtained by stirring for 30 minutes. At this time, the compounding quantity of BCP was adjusted so that content in the obtained composition for cold preservation might be 8 ppm. Table 2 shows the content of each compounding component and its composition for cold storage. In Table 2, “basic salt” in the column of the blending component means a basic salt other than phosphate and monohydrogen phosphate. In addition, trisodium phosphate dodecahydrate is described by omitting crystal water (12H ₂ O). The same applies to the following tables.

  Table 7 shows physical properties such as pH (α1), pH (α2), pH (α3), pKa of a pH indicator when the solvent is water and the temperature is 25 ° C., and the pH of the composition for cold preservation. The pH (α1), pH (α2), pH (α3) and the pH were all measured with the temperature of the measurement object being 25 ° C. The ratio of the total content of the acidic inorganic salt and the phosphate to the total content of the inorganic salt in the obtained composition for cold insulation (hereinafter, this value may be indicated by the symbol “(X1)”) Table 7 shows.

  Next, the obtained cold insulation composition was sealed in a container made of high density polyethylene to obtain the cold insulation tool of the first embodiment.

<Evaluation of composition for cold preservation>
(Color change)
The obtained composition for cold insulation (cold insulation tool) was cooled to -25 ° C. During this time, the composition for cold preservation was frozen at a temperature higher than −25 ° C. and changed in color before and after freezing. And the color change of the composition for cold preservation before and behind this freezing was evaluated visually according to the following reference | standard. The results are shown in Table 9. Table 9 also shows the color change range and color change of the pH indicator used.

In Table 9, “color change” described in the evaluation result column indicates a color change of the cold-retaining composition before and after freezing. For example, “green → yellow” means a cold-retaining composition. Indicates that the color was green before freezing and yellow after freezing.
○: The color change before and after freezing is large and the cooling state is very easy to visually recognize.
(Triangle | delta): The color change before and behind freezing can be discriminate | determined and the visual recognition of a cooling state is possible.
X: The color change before and after freezing is unclear, and it is difficult or impossible to visually recognize the cooling state.

  Further, in Table 9, “low pH → high pH color change” described in the column of the color change region of the pH indicator means that the pH of the liquid containing the pH indicator is higher than a specific value. When the pH indicator changes to a value, the pH indicator shows the color change within the color change range.For example, “yellow → purple” means that the pH indicator changes the color of the liquid from yellow to purple in the process of increasing the pH of the liquid. Indicates to change.

<Manufacture of composition for cold preservation and cold insulation tool (first embodiment), evaluation of composition for cold insulation>
[Examples 2 to 13]
The composition for cold insulation and the cold insulation of the first embodiment are the same as those of Example 1, except that the components of the cold insulation composition and the content in the cold insulation composition are as shown in Tables 2 and 3. A tool was manufactured and a cold insulation composition was evaluated. Table 7 shows the physical properties and Table 9 shows the evaluation results.

[Example 14]
<Manufacture of composition for cold preservation and cold insulation tool (second embodiment)>
Under room temperature (20-25 ° C.), BCP is added and dissolved in water (78.90 parts by mass), and then ammonium chloride (9.70 parts by mass), potassium chloride (9.70 parts by mass) and Obtained by adding diammonium hydrogen phosphate (0.50 parts by mass) and then dissolving CMC (1.10 parts by mass) while stirring at room temperature for 1 hour After confirming that the liquid was sufficiently thickened, a preservative (0.05 parts by mass) was added, and the mixture was stirred at room temperature for 30 minutes to obtain a composition for cold preservation. At this time, the compounding quantity of BCP was adjusted so that content in the obtained composition for cold preservation might be 8 ppm. Table 3 shows the content of each compounding component and its composition for cold storage.

  Table 7 shows physical properties such as pH (α1), pH (α2), pH (α3), pKa of a pH indicator when the solvent is water and the temperature is 25 ° C., and the pH of the composition for cold preservation. The pH (α1), pH (α2), pH (α3) and the pH were all measured with the temperature of the measurement object being 25 ° C. Ratio of total content of acidic inorganic salt and monohydrogen phosphate with respect to the total content of inorganic salt in the obtained composition for cold insulation (hereinafter, this value may be indicated by “(X2)”) ), And the ratio of the content of monohydrogen phosphate to the total content of water, inorganic salt and thickener (hereinafter, this value may be indicated by the symbol “(X3)”) is also shown in Table 7. ing.

  Next, the obtained cold insulation composition was sealed in a container made of high density polyethylene to obtain the cold insulation tool of the second embodiment.

<Evaluation of composition for cold preservation>
The obtained composition for cold insulation was evaluated in the same manner as in Example 1. The results are shown in Table 9.

<Manufacture of composition for cold preservation and cold insulation tool (second embodiment), evaluation of composition for cold insulation>
[Examples 15 to 33]
The composition for cold preservation of 2nd Embodiment and the composition of the composition for cold preservation and the content in the composition for cold preservation were the same as Example 14 except that it was as shown in Tables 3-5. A cold insulation tool was manufactured, and the composition for cold insulation was evaluated. The physical properties are shown in Tables 7 to 8, and the evaluation results are shown in Table 9, respectively.

[Example 34]
<Manufacture of a composition for cold preservation and a cold insulation tool (third embodiment)>
At room temperature (20 to 25 ° C.), MR is added and dissolved in water (79.35 parts by mass), and then ammonium chloride (9.75 parts by mass) and potassium chloride (9.75 parts by mass) are added. Then, CMC (1.10 parts by mass) was added and stirred for 1 hour at room temperature to dissolve, and it was confirmed that the obtained liquid was sufficiently thickened. Thereafter, a preservative (0.05 parts by mass) was added, and the mixture was stirred at room temperature for 30 minutes to obtain a composition for cold preservation. At this time, the blending amount of MR was adjusted so that the content in the obtained cold insulation composition was 8 ppm. Table 5 shows the content of each compounding component and its composition for cold storage.

  Further, Table 8 shows physical properties such as pH (α1), pH (α2), pH (α3), pKa of pH indicator when the solvent is water and the temperature is 25 ° C., pH of the composition for cold preservation, and the like. The pH (α1), pH (α2), pH (α3) and the pH were all measured with the temperature of the measurement object being 25 ° C. Table 8 also shows the ratio of the content of the acidic inorganic salt to the total content of the inorganic salt in the obtained cold-retaining composition (hereinafter, this value may be indicated by “(X4)”). Yes.

  Next, the obtained cold insulation composition was sealed in a container made of high-density polyethylene to obtain the cold insulation tool of the third embodiment.

<Evaluation of composition for cold preservation>
The obtained composition for cold insulation was evaluated in the same manner as in Example 1. The results are shown in Table 9.

<Manufacture of composition for cold preservation and cold insulation tool (third embodiment), evaluation of composition for cold insulation>
[Examples 35 to 37]
The composition for cold insulation and the cold insulation tool of the third embodiment were the same as in Example 34 except that the components of the cold insulation composition and the content in the cold insulation composition were as shown in Table 5. And the composition for cold preservation was evaluated. Table 8 shows the physical properties and Table 9 shows the evaluation results.

<Manufacture of composition for cold preservation and cold insulation, evaluation of composition for cold insulation>
[Comparative Examples 1 to 9]
A composition for cold insulation and a cold insulation tool were produced in the same manner as in Example 1 except that the components in the cold insulation composition and the content in the cold insulation composition were as shown in Tables 5 and 6, The composition for cold preservation was evaluated. Table 8 shows the physical properties and Table 9 shows the evaluation results.

  As is clear from the above results, the cold insulator according to the first embodiment of the present invention (Examples 1 to 13), the cold insulator according to the second embodiment (Examples 14 to 33), and the cold insulator according to the third embodiment. In each of the ingredients (Examples 34 to 37), the color of the cold-retaining composition clearly changes before and after freezing, reflecting the change in color of the pH indicator as the inorganic salt precipitates upon freezing. The cooling state was easily visible.

  Among the cold insulators according to the first embodiment, in particular, in the cold insulators of Examples 1 to 3, 8 to 11 and 13, the time required for completing the color change of the cold insulation composition was short, and particularly preferable properties were exhibited. .

  Among the cold insulators according to the second embodiment, in particular, in the cold insulators of Examples 22 to 27, the time required for completing the color change of the cold insulation composition was short, and particularly preferable properties were exhibited. This has shown that there exists a tendency which shows such a preferable property, when the composition for cold preservation contains a dihydrogen phosphate salt and a neutral inorganic salt.

  On the other hand, in the cold insulation tools of Comparative Examples 1 to 9, the cold insulation composition is different from that in the above examples, the color change is unclear before and after freezing, and the cooling state is visually recognized. Was difficult or impossible.

<Manufacture of composition for cold preservation and cold insulation tool (first embodiment), evaluation of composition for cold insulation>
[Examples 38 to 40]
The composition for cold insulation and the cold insulation tool of the first embodiment were the same as in Example 1 except that the composition components of the cold insulation composition and the content in the cold insulation composition were as shown in Table 10. Manufactured and evaluated compositions for cold storage. Each physical property is shown in Table 11, and the evaluation result is shown in Table 12.

<Manufacture of composition for cold preservation and cold insulation tool (second embodiment), evaluation of composition for cold insulation>
[Examples 41 to 46]
The composition for cold insulation and the cold insulation tool of the second embodiment were the same as in Example 14, except that the components of the cold insulation composition and the content in the cold insulation composition were as shown in Table 10. Manufactured and evaluated compositions for cold storage. Each physical property is shown in Table 11, and the evaluation result is shown in Table 12.

  As described above, in the cold insulator (Examples 38 to 40) according to the first embodiment of the present invention, the cold insulator (Examples 41 to 46) according to the second embodiment, With the precipitation of inorganic salts during freezing, the color changed clearly before and after freezing, reflecting the change in color development of the pH indicator, and the cooling state could be easily visually confirmed.

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

Claims (7)

A cold insulator provided with a cold insulating composition containing water, an inorganic salt, a thickener and a pH indicator,
The composition for cold preservation contains, as the inorganic salt, an acidic inorganic salt whose aqueous solution is acidic, and a phosphate,
In the composition for cold preservation, the ratio of the total content of the acidic inorganic salt and phosphate to the total content of the inorganic salt is 5 to 100% by mass,
The composition for cold preservation contains, as the acidic inorganic salt, an inorganic salt other than dihydrogen phosphate and dihydrogen phosphate,
The pH indicator has a pKa of 4.9-8.0,
In the composition for cold preservation, the pH (α1) when all the components other than phosphate, dihydrogen phosphate and water are removed is expressed by the following formula (i) with respect to the pKa. A cooler that meets the requirements.
pKa of pH indicator ≦ pH (α1) ≦ pKa of pH indicator + 1.8 (i)   The cold-retaining tool according to claim 1, wherein the cold-retaining composition has a pH of 4.6 to 8.8.   The said composition for cold preservation is what pH ((alpha) 3) at the time of substituting all the components other than the said thickener and water with water will be 6.0-8.5. The cold insulation described. A cold insulator provided with a cold insulating composition containing water, an inorganic salt, a thickener and a pH indicator,
The composition for cold preservation contains, as the inorganic salt, an acidic inorganic salt whose aqueous solution is acidic, and a monohydrogen phosphate salt,
In the composition for cold preservation, the ratio of the total content of the acidic inorganic salt and monohydrogen phosphate to the total content of the inorganic salt is 5 to 100% by mass,
In the composition for cold preservation, the ratio of the content of monohydrogen phosphate to the total content of water, the inorganic salt, and the thickener is 0.2 to 5.0% by mass,
A cold insulator, wherein the pH indicator has a pKa of 4.9 to 8.0.   The cold-retaining tool according to claim 4, wherein the pH of the cold-retaining composition is 4.7 to 8.0.   The said composition for cold preservation is what pH ((alpha) 3) at the time of substituting all the components other than the said thickener and water with water will be 6.0-9.1. The cold insulation described. A cold insulator provided with a cold insulating composition containing water, an inorganic salt, a thickener and a pH indicator,
The composition for cold preservation contains an acidic inorganic salt whose aqueous solution is acidic as the inorganic salt,
In the composition for cold preservation, the ratio of the content of the acidic inorganic salt to the total content of the inorganic salt is 5 to 100% by mass,
The composition for cold preservation is such that the pH (α2) is 7 or less when all the components other than the inorganic salt and water are replaced with water,
The composition for cold preservation has a pH (α3) of 7 or more when all components other than the thickener and water are replaced with water,
pH (α2) and pH (α3) indicate values in different pH ranges among the three pH ranges of pH lower than the color change range of the pH indicator, pH of the color change range, and pH higher than the color change range. , Cooler.