TWI697555B - Refrigerant pack - Google Patents

Abstract

A refrigerant pack is provided including a refrigerant substance which contains water, an inorganic salt, a thickener, and a pH indicator, wherein the refrigerant substance contains as the inorganic salt, an acidic inorganic salt in which the solution shows acidity, and phosphate; in the refrigerant substance, the ratio of the total amount of the acidic inorganic salt and phosphate with respect to the total amount of the inorganic salt is 5 to 100 % by mass; the refrigerant substance contains dihydrogenphosphate and an inorganic salt other than dihydrogenphosphate as the acidic inorganic salt; pKa of the pH indicator is 4.9 to 8.0; and in the refrigerant substance, pH(α1), in which all contents other than phosphate, dihydrogenphosphate, and water, are removed, satisfies a relationship represented by the following formula (i) with respect to the pKa: pKa of the pH indicator ≤ pH(α1) ≤ pKa of the pH indicator + 1.8 (i)

Description

Cooler

TECHNICAL FIELD The present invention relates to a cold preservation device provided with a cold preservation composition which can easily recognize the color change during cooling. This case claims priority based on Special Application No. 2015-185043 filed in Japan on September 18, 2015, and its content is used here.

Background Art Cooling appliances are widely used for cold preservation during storage or transportation of various fresh products, and they can usually be reused. This kind of cold preservation device is provided with a cold preservation composition having a cold preservation effect, and is constituted by sealing the cold preservation composition in a container having thermal conductivity. The known cold preservation composition contains a coloring agent so that its existence can be easily recognized from the outer side of the cold preservation device. For example, there is currently disclosed a cold preservation device in which a cold preservation composition that has been colored by a dye is enclosed. And it is configured that the enclosed amount can be easily confirmed from the outside (refer to Patent Document 1).

However, even if the cold insulation composition described in Patent Document 1 contains a dye, it is difficult to visually confirm the presence or absence of a cooling state such as freezing, and whether the cold insulation device is sufficiently cooled to the desired temperature that can keep the cold, and has the identification of the cooling state Difficult question.

Prior Art Documents Patent Documents Patent Document 1: JP 2006-97984 A

SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION The subject of the present invention is to provide a cooler that can easily recognize whether the cooling state is in the target state.

Means to Solve the Problem The first aspect of the present invention is a cold-preservation appliance comprising a cold-preservation composition, the cold-preservation composition containing water, an inorganic salt, a thickener, and a pH indicator; the aforementioned cold-preservation composition contains The aqueous solution is acidic acidic inorganic salt and phosphate as the aforementioned inorganic salt; in the aforementioned cold preservation composition, the ratio of the total content of the aforementioned acidic inorganic salt and phosphate relative to the total content of the aforementioned inorganic salt is 5-100 mass %; The aforementioned cold preservation composition contains dihydrogen phosphate and inorganic salts other than dihydrogen phosphate as the aforementioned acidic inorganic salt; the aforementioned pH indicator has a pKa of 4.9 to 8.0; the aforementioned cold preservation composition removes phosphate and dihydrogen phosphate When all components other than hydrogen salt and water are contained, its pH (α1) satisfies the relationship shown in the following formula (i) with respect to the aforementioned pKa. pH indicator pKa≦pH(α1)≦pH indicator pKa+1.8‥‥(i)

In the first aspect of the present invention, the pH of the composition for cold preservation may be 4.6 to 8.8. In the first aspect of the present invention, the cold preservation composition may have a pH (α3) of 6.0 to 8.5 when water is used to replace all components other than the thickener and water.

In addition, a second aspect of the present invention is a cold preservation device comprising a composition for cold preservation, the composition for cold preservation contains water, an inorganic salt, a thickener, and a pH indicator; the composition for cold preservation contains an aqueous solution of which is acidic The acidic inorganic salt and monohydrogen phosphate as the aforementioned inorganic salt; in the aforementioned cold preservation composition, relative to the total content of the aforementioned inorganic salt, the ratio of the total content of the aforementioned acidic inorganic salt and monohydrogen phosphate is 5-100 mass %; In the aforementioned cold preservation composition, the ratio of the content of monohydrogen phosphate relative to the total content of water, the aforementioned inorganic salt and the thickener is 0.2~5.0% by mass; the pKa of the aforementioned pH indicator is 4.9~8.0 .

In the second aspect of the present invention, the pH of the aforementioned cold preservation composition may be 4.7 to 8.0. In the second aspect of the present invention, the cold preservation composition may have a pH (α3) of 6.0 to 9.1 when water is used to replace all components other than the thickener and water.

In addition, a third aspect of the present invention is a cold preservation device comprising a composition for cold preservation, the composition for cold preservation contains water, an inorganic salt, a thickener, and a pH indicator; the composition for cold preservation contains an aqueous solution of which is acidic The acidic inorganic salt as the aforementioned inorganic salt; in the aforementioned cold preservation composition, the proportion of the aforementioned acidic inorganic salt relative to the total content of the aforementioned inorganic salt is 5-100% by mass; the aforementioned cold preservation composition is made of water The pH (α2) when substituting all the ingredients other than the aforementioned inorganic salt and water is 7 or less; the pH (α3) of the aforementioned cold preservation composition is 7 when replacing all the ingredients other than the thickener and water with water Above; pH(α2) and pH(α3) are lower than the pH of the discoloration zone of the aforementioned pH indicator, the pH of the discoloration zone, and the pH of the discoloration zone, and will show different pH ranges. The value.

Effects of the Invention The cooling device of the present invention can easily recognize whether the cooling state is in the target state.

Modes for Carrying Out the Invention Hereinafter, preferred examples of the cooling appliance of the present invention will be described. However, the present invention is not limited to these examples. For example, additions, omissions, substitutions, and other changes (amount, number, position, size, etc.) can be made without departing from the scope of the present invention.

In addition, in this specification, unless otherwise stated, the unit "ppm" of the content (blending amount, concentration) is based on the mass ratio.

＜＜First embodiment＞＞ The cold storage device related to the first embodiment of the present invention is provided with a cold insulation composition containing water, an inorganic salt, a thickener, and a pH indicator; the aforementioned cold insulation composition contains it The acidic inorganic salt and phosphate whose aqueous solution is acidic are used as the aforementioned inorganic salt; in the aforementioned cold preservation composition, the ratio of the total content of the aforementioned acidic inorganic salt and phosphate relative to the total content of the aforementioned inorganic salt is 5-100% by mass ; The aforementioned cold preservation composition contains dihydrogen phosphate and inorganic salts other than dihydrogen phosphate as the aforementioned acidic inorganic salt; the aforementioned pH indicator has a pKa of 4.9 to 8.0; the aforementioned cold preservation composition is removing phosphate and dihydrogen phosphate When all components other than salt and water are contained, the pH (α1) and the aforementioned pKa satisfy the relationship shown in the following formula (i). pH indicator pKa≦pH(α1)≦pH indicator pKa+1.8‥‥(i)

The color of the cold preservation composition of the aforementioned cold preservation appliance changes significantly before and after the freezing of the cold preservation composition. Here, the color of the cold preservation composition reflects the presence or absence of color development of the pH indicator. Therefore, the aforementioned cooler can easily recognize whether the cooling state is in the target state (a state in which the object can be sufficiently cooled). In addition, the color of the cold preservation composition before and after freezing does not mainly reflect the color of the components themselves other than the pH indicator such as the aforementioned inorganic salt and thickener.

The composition for cold preservation in the first embodiment contains an inorganic salt and a thickener as components that affect its acidity. In addition, in the aforementioned cold preservation composition, the aforementioned inorganic salt is selected from a specific combination of acidic inorganic salts of dihydrogen phosphate, inorganic salts other than dihydrogen phosphate of acidic inorganic salts and phosphates, and these inorganic salts are limited The content of the salt is used for the combination of the inorganic salt and the pH indicator whose pKa is in a specific range. The aforementioned cold-keeping composition having such a structure can change color significantly and greatly depending on the color development of the pH indicator or the presence or absence of color development.

<Inorganic salt> The aforementioned inorganic salt in the first embodiment has a function as a component of the cooling agent, and the freezing temperature of the cooling composition is determined mainly according to the type and amount. In addition, the aforementioned inorganic salt is not a component of the aforementioned pH indicator, and precipitates as crystalline or amorphous (amorphous) when the cold preservation composition is frozen, and the presence or absence of the precipitation interferes with the color change of the cold preservation composition .

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

[Acid inorganic salt] (Dihydrogen phosphate) In the first embodiment, one hydrogen ion in the dihydrogen phosphate-based phosphoric acid (H ₃ PO ₄ ) used as the aforementioned acidic inorganic salt is replaced by a cation , It can be non-hydrate or hydrate. For example, the dihydrogen phosphate in the first embodiment includes sodium dihydrogen phosphate (NaH ₂ PO ₄ ), potassium dihydrogen phosphate (KH ₂ PO ₄ ), and calcium dihydrogen phosphate (Ca(H ₂ PO ₄ ) ₄ ) ₂ ) and other dihydrogen phosphate metal salts; dihydrogen phosphate non-metal salts such as ammonium dihydrogen phosphate (NH ₄ H ₂ PO ₄ ), etc.

The dihydrogen phosphate contained in the composition for cold preservation in the first embodiment may be one type or two or more types, and if there are two or more types, the combination and the ratio can be arbitrarily selected.

(Inorganic salt other than dihydrogen phosphate) In the first embodiment, an inorganic salt other than dihydrogen phosphate, which is the aforementioned acidic inorganic salt, is used as long as the aqueous solution is acidic, and there is no particular limitation. Non-hydrates may also be hydrates. For example, the inorganic salts other than the aforementioned dihydrogen phosphate in the first embodiment include: 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 composition _{(Ca (NO 3) 2 .4H} 2 O), calcium nitrate (Ca (NO _{3) 2),} etc., it is preferable that the ammonium chloride, ammonium nitrate.

The inorganic salt other than the dihydrogen phosphate contained in the composition for cold preservation in the first embodiment may be one type or two or more types. If there are two or more types, the combination and ratio of the inorganic salts can be arbitrarily selected .

[Phosphate] The aforementioned phosphate in the first embodiment is obtained by substituting three hydrogen ions in phosphoric acid (H ₃ PO ₄ ) with cations, and may be a non-hydrate or a hydrate. The aforementioned phosphate is usually an alkaline salt whose aqueous solution is alkaline.

For example, the phosphates in the first embodiment include trisodium phosphate (Na ₃ PO ₄ ), trisodium phosphate dodecahydrate (Na ₃ PO ₄ ．12H ₂ O), tripotassium phosphate (K ₃ PO ₄ ) and other phosphate trimetal salts; triammonium phosphate ((NH ₃ ) ₃ PO ₄ ) and other phosphate trimetal salts, etc., preferably trisodium phosphate (Na ₃ PO ₄ ), trisodium phosphate dodecahydrate , Tripotassium phosphate (K ₃ PO ₄ ).

The phosphate contained in the composition for cold preservation in the first embodiment may be only one type or two or more types, and if there are two or more types, the combination and ratio of these can be arbitrarily selected.

[Other inorganic salts] In addition to the aforementioned acidic inorganic salts (inorganic salts other than dihydrogen phosphate and dihydrogen phosphate) and phosphates, the cold preservation composition in the first embodiment may contain any of these One of the other inorganic salts is the aforementioned inorganic salt. The aforementioned other inorganic salts may be non-hydrates or hydrates.

As long as the effect of the present invention is not impaired, the aforementioned other inorganic salts in the first embodiment are not particularly limited. For example, there can be mentioned: a neutral inorganic salt whose aqueous solution is neutral, and a phosphoric acid whose aqueous solution is alkaline. Inorganic salts other than salt, etc.

For example, the aforementioned neutral inorganic salts can include sodium chloride (NaCl), potassium chloride (KCl), calcium chloride (CaCl ₂ ), sodium sulfate (Na ₂ SO ₄ ), potassium sulfate (K ₂ SO ₄ ), 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 ), etc. Among them, the aforementioned neutral inorganic salt is preferably sodium chloride or potassium chloride.

The basic inorganic salt other than the aforementioned phosphate is preferably an inorganic salt other than monohydrogen phosphate. For example, sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium bicarbonate ( NaHCO ₃ ), potassium bicarbonate (KHCO ₃ ), sodium sulfite (Na ₂ SO ₃ ), borax (Na ₂ B ₄ O ₇ ), etc. Among them, the alkaline inorganic salt other than the aforementioned phosphate is preferably sodium carbonate or potassium carbonate.

The aforementioned other inorganic salt contained in the composition for cold preservation in the first embodiment may be only one type or two or more types, and if there are two or more types, the combination and ratio thereof can be arbitrarily selected.

In the cold preservation composition of 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 5-100% by mass, preferably 5.5-100% by mass . By making the said ratio more than the said lower limit, the color change of the composition for cold preservation before and after freezing becomes large. In such a numerical range, the lower limit of the aforementioned ratio can be selected from, for example, 10% by mass, 20% by mass, 30% by mass, 40% by mass, and 45% by mass, but it is not limited to these. In addition, in such a numerical range, the upper limit of the aforementioned ratio can be selected, for example, 90% by mass, 80% by mass, 70% by mass, 60% by mass, 55% by mass, etc. However, it is not limited to these.

Before freezing in the first embodiment, it is preferable that the dissolved amount of the aforementioned inorganic salt in the composition for cold preservation at 0°C or higher is as large as possible. The dissolved amount of the aforementioned inorganic salt is preferably 90%. Mass% or more, preferably 95 mass% or more, more preferably 98 mass% or more, or 100 mass% (full amount). In addition, in the composition for cold preservation after freezing in the first embodiment, the more the amount of precipitation of the aforementioned inorganic salt, the better, and the amount of precipitation of the total amount of the aforementioned inorganic salt is preferably 90% by mass or more, which is more preferable It is 95% by mass or more, more preferably 98% by mass or more, or 100% by mass (all).

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 particularly preferably 15 to 25% by mass.

<Thickener> The thickener in the first embodiment increases the consistency of the cold-keeping composition and is not a component of the pH indicator. The aforementioned thickener in the first embodiment is preferably a thickener that does not precipitate when the composition for cold preservation is frozen. In addition, in this specification, "the thickener does not precipitate when the cold preservation composition freezes" means that when the cold preservation composition freezes, the thickener can be directly solidified in a state of being dissolved in water, rather than a large amount Aggregation is inferred that the thickener molecules are directly solidified in a state surrounded by water molecules, and it is speculated that it is not a state in which a large number of thickener molecules aggregate and solidify.

The aforementioned thickener in the first embodiment is not particularly limited. For example, acrylic polymers (compounds having a polyacrylic acid skeleton) such as polyacrylic acid and sodium polyacrylate can be cited; carboxymethyl cellulose ( CMC) and other carboxyalkyl cellulose; guar gum; hydroxyalkyl guar such as hydroxypropyl guar; pectin; xanthan gum; tamarind gum; carrageenin; propylene glycol and other alkanediols.

The aforementioned thickener in the first embodiment is preferably selected from acrylic polymers, carboxyalkyl cellulose, xanthan gum, guar gum, hydroxyalkyl guar gum, pectin, tamarind gum, antlers One or more of the group consisting of cabbage glycoside and alkanediol. In addition, the aforementioned thickener is more preferably one or more selected from the group consisting of acrylic polymer, carboxyalkyl cellulose, xanthan gum, guar gum, and hydroxyalkyl guar gum. By using such a thickener, the color change of the cold preservation composition before and after freezing is large, and the handling properties are more excellent.

The thickener contained in the composition for cold preservation in the first embodiment may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be arbitrarily selected.

In the composition for cold preservation before and after freezing in the first embodiment, the smaller the amount of thickener precipitated, the better, and the amount of precipitated is preferably 10% by mass or less in the total amount of thickener. It is desirably 5% by mass or less, more desirably 2% by mass or less, and particularly desirably 0% by mass (all unprecipitated).

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

<pH indicator> The aforementioned pH indicator (acid-base indicator) in the first embodiment is a component that reflects the presence or absence of color development and determines the color of the cold-keeping composition. By containing a pH indicator, the cold preservation composition changes color before and after freezing.

The aforementioned 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 stated, the pKa of the pH indicator in this embodiment means the value when the solvent is water and the temperature is 25°C.

The pH indicator has a pH range in which the discoloration can be observed, that is, the discoloration zone. The pH indicator in the solution can be divided into dissociated form and undissociated form, and a dissociation equilibrium is established between them. The color presented by the dissociated form and the undissociated form will be different, however, outside the discoloration zone , The balance will obviously be biased towards either the dissociated form or the undissociated form, and only the color of one can be seen. However, the dissociated form and the undissociated form of the pH indicator in the discoloration zone are mixed in a comparable amount, and the mixture of the two colors can be seen ("Dictionary of Chemistry 39th Brush, September 15, 2006" , Gongli Publishing Co., Ltd.").

Table 1 shows examples of major pH indicators. In addition to the pH indicator in Table 1, the discoloration area and color change are also recorded. In addition, the "color change (low pH→high pH)" in Table 1 means the color change displayed by the pH indicator in the color change area 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 in the process of increasing the pH of the aforementioned liquid, the pH indicator will change the aforementioned liquid from red to yellow.

[Table 1]

For example, the pH indicator in the first embodiment should preferably have a discoloration zone (pH) in the range of 3.0 to 10.5, more preferably in the range of 4.0 to 9.5, and particularly preferably in the range of 4.5 to 9.0 Within the range.

The pH indicator contained in the composition for cold preservation in the first embodiment may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be arbitrarily selected. However, in general, it is desirable to contain only one pH indicator.

As long as it is a color change that can achieve the goal of the cold-keeping composition, the content of the pH indicator in the cold-keeping composition in the first embodiment is not particularly limited. However, it is preferably 1 to 30 ppm, and more preferably 5~20ppm.

<Other components> In addition to water, an inorganic salt, a thickener, and a pH indicator, the composition for cold preservation in the first embodiment may contain other components other than these within a range that does not impair the effects of the present invention. Examples of the aforementioned other components include: solvents other than water; various well-known additives such as preservatives and surfactants. The aforementioned other components contained in the composition for cold preservation in the first embodiment may be only one type or two or more types, and if there are two or more types, the combinations and ratios thereof can be arbitrarily selected.

(Solvent) The aforementioned solvent in the first embodiment is preferably a solvent that can dissolve the aforementioned inorganic salt, thickener, and pH indicator. For example, such a solvent may include alcohol.

Water and the aforementioned solvent are components that have a function as a component of the cooling agent, and the freezing temperature of the cooling-preserving composition is determined mainly according to the type and amount together with the aforementioned inorganic salt. In the cold preservation composition of 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, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

(Preservatives) For example, the preservatives in the first embodiment include food preservatives, antioxidants, etc., more specifically, sodium pyrithione, parabens ( P-hydroxybenzoate), protamine, organic nitrogen and sulfur compounds, etc.

The content of the preservative in the composition for cold preservation in the first embodiment is not particularly limited, but it is preferably 0.02 to 0.5% by mass, and more preferably 0.04 to 0.2% by mass.

(Surfactant) Examples of the aforementioned surfactant in the first embodiment include: well-known surfactants, for example, alkyl sulfates such as sodium lauryl sulfate; alkyl sulfates such as sodium caprate Carboxylate; N-alkyl propylene amide such as N-isopropyl propylene amide; Polyoxyethylene dialkyl ether such as polyoxyethylene octyl dodecyl ether; Polyoxyethylene monomer such as polyoxyethylene lauryl ether Alkyl ether; polyoxyethylene monoalkenyl ether such as polyoxyethylene oleyl ether.

The composition for cold preservation in the first embodiment, with respect to the total content of water and components other than the aforementioned solvent (the aforementioned inorganic salt, thickener, pH indicator, and other components other than the aforementioned solvent), the aforementioned inorganic salt, thickening The ratio of the total content of the agent and the pH indicator is preferably 90% by mass or more, more preferably 93% by mass or more, more preferably 96% by mass or more, particularly preferably 98% by mass or more, or 100% by mass %. By making the ratio of the aforementioned total content more than the aforementioned lower limit, the color change of the cold preservation composition before and after freezing is greater.

The pH (α1) of the composition for cold preservation in the first embodiment when all components other than phosphate, dihydrogen phosphate, and water are removed is that the pKa of the aforementioned pH indicator satisfies the following formula (i) relationship. pH indicator pKa≦pH(α1)≦pH indicator pKa+1.8‥‥(i) pH(α1) is equivalent to the pH of the mixed solution, which is only mixed with the cold preservation composition in the first embodiment Contains equal amounts of phosphate, dihydrogen phosphate, and water (for example, an aqueous solution containing phosphate and dihydrogen phosphate). Regarding the mixture of phosphate and dihydrogen phosphate used in the aforementioned cold preservation composition, pH (α1) is an index of its acidity.

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

After satisfying the relationship of the aforementioned formula (i), the pH (α1) is more preferably 5.0 to 10.6, more preferably 5.3 to 10.3, and particularly preferably 5.6 to 10.0.

The pH of the cold preservation composition in the first embodiment is preferably 4.6 to 8.8, more preferably 4.9 to 8.5, and particularly preferably 5.1 to 8.3. The composition for cold preservation in the first embodiment preferably has a pH in the aforementioned numerical range at the temperature at which the pH indicator is dissolved in the composition for cold preservation. More preferably, the temperature of the composition for cold preservation is 25°C. The pH of the aforementioned numerical range is displayed. In addition, in the present embodiment, unless otherwise stated in advance, the description of the composition for cold preservation simply "pH" means the pH of the composition for cold preservation itself.

The pH (α2) of the composition for cold preservation in the first embodiment when replacing all components other than the inorganic salt and water with water is preferably 4.4 to 8.7, more preferably 4.9 to 8.2. The pH (α2) is equivalent to the pH of water containing inorganic salts (for example, an aqueous solution of inorganic salts). The water containing inorganic salts contains only the aforementioned inorganic salts, and the content (mass%) is the same as the content (mass%) in the aforementioned cold preservation composition )the same. The pH (α2) is an index of the acidity of the inorganic salt used in the aforementioned cold preservation composition. The pH (α2) is preferably the pH at the temperature at which the pH indicator is dissolved in the composition for cold preservation, and more preferably the pH when the water containing the inorganic salt is 25°C.

The pH (α3) of the composition for cold preservation in the first embodiment when water is substituted for the thickener and all components other than water is preferably 6.0 to 8.5, more preferably 6.0 to 8.3, for example , Can be 6.0~8.0, or 6.5~7.5. The pH (α3) corresponds to the pH of water containing a thickener (for example, an aqueous solution of a thickener). The water containing a thickener contains only the aforementioned thickener, and the content (% by mass) is the same as that of the aforementioned cold preservation composition The content (mass %) is the same. The pH (α3) is an index of acidity of the thickener used in the aforementioned cold preservation composition. The pH (α3) is preferably the pH at the temperature at which the pH indicator is dissolved in the composition for cold preservation, and more preferably the pH at which the thickener-containing water is 25°C.

The composition for cold preservation in the first embodiment is prepared by blending water, the aforementioned inorganic salt, a thickener, a pH indicator, and the aforementioned other components as necessary. The blending method of each component is not particularly limited, and it can be arbitrarily adjusted so that each component is uniformly dissolved or dispersed at a temperature higher than the freezing temperature of the cold preservation composition. For example, in the blending of the ingredients, all the ingredients can be mixed after adding them, or they can be mixed while adding a part of the ingredients in sequence, or they can be mixed while adding all the ingredients in sequence. The mixing method is not particularly limited, and can be appropriately selected from the following known methods: a method of mixing by rotating a stirrer or a stirring blade; mixing using a mixer, three-roller, kneader, or bead mill, etc. The method; the method of mixing by applying ultrasonic waves, etc.

The cold preservation device according to the first embodiment of the present invention is provided with the aforementioned composition for cold preservation, and can be constructed by holding the composition for cold preservation by a holding mechanism such as a container or bag that can contain a liquid substance.

As long as it has transparency that can recognize the color change (discoloration) of the retained cold preservation composition, the material of the retaining mechanism is not particularly limited. For example, the material of the ideal holding mechanism may include: polyolefin such as polyethylene and polypropylene; polyamide; synthetic resin such as polyester. For example, the polyethylene may be low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and the like.

The material or size of the aforementioned holding mechanism can be selected in consideration of, for example, the shape of the holding mechanism, the holding amount of the cold-keeping composition, or the color change method of the cold-keeping composition before and after freezing. For example, in the case of a bag-shaped holding mechanism, an example of an ideal holding mechanism material can be low-density polyethylene. Furthermore, in the case of a container-shaped holding mechanism, an example of an ideal material for the holding mechanism includes high-density polyethylene. For example, the bag-shaped holding mechanism is suitable for the case where it is used as a small holding mechanism, that is, the case where the holding amount of the cold preservation composition is small. In addition, the container-shaped holding mechanism is suitable for the case where it is used as a large holding mechanism, that is, when the holding amount of the cold-keeping composition is large. However, the selection method of the material or size of the holding mechanism shown here is only an example.

From the viewpoint of excellent resistance to low temperature, brittleness, water resistance, and chemical resistance, the material of the aforementioned holding mechanism is preferably polyolefin. Furthermore, from the viewpoint of easy molding and high strength, it is more preferable High-density polyethylene.

The thickness of the flat parts such as film or sheet in the aforementioned holding mechanism is not particularly limited, however, it is preferably 5~200μm.

The flat part may be composed of a single layer, or may be composed of multiple layers of two or more layers. When the aforementioned flat part is composed of a plurality of layers, the plurality of layers may be the same or different from each other. That is, all layers may be the same, all layers may be different, or only some of the layers may be the same. Moreover, when the plural layers are different from each other, there is no special restriction on the combination of the plural layers. Here, that the plural layers are different from each other means that at least one of the material and thickness of each layer is different from each other. When the aforementioned flat part is composed of a plurality of layers, the total thickness of each layer can be the thickness that can constitute the above-mentioned ideal flat part.

The composition for cold preservation in the first embodiment greatly changes color before and after freezing, so the presence or absence of freezing can be easily recognized. In addition, the discoloration of the cold preservation composition can be recognized from the outside of the cold preservation device. Thereby, it can be easily recognized whether the cold storage device is sufficiently cooled to the desired temperature. In addition, even if the composition for cold preservation is repeatedly cooled and heated, such as repeated freezing and thawing, the effect will not be impaired. Therefore, the cold preservation appliance provided with the aforementioned composition for cold preservation is also suitable for repeated use.

<<Second Embodiment>> The cold storage device according to the second embodiment of the present invention is provided with a cold insulation composition containing water, an inorganic salt, a thickener, and a pH indicator; the aforementioned cold insulation composition contains The acidic inorganic salt and monohydrogen phosphate whose aqueous solution is acidic are used as the aforementioned inorganic salt; in the aforementioned cold preservation composition, the ratio of the total content of the aforementioned acidic inorganic salt and monohydrogen phosphate relative to the total content of the aforementioned inorganic salt is 5-100% by mass; in the aforementioned cold preservation composition, relative to the total content of water, the aforementioned inorganic salt and thickener, the ratio of the content of monohydrogen phosphate is 0.2-5.0% by mass; the pKa of the aforementioned pH indicator It is 4.9~8.0.

The color of the composition for cold preservation of the said cold preservation|seat will change significantly before and after freezing the composition for cold preservation. Here, the color of the cold preservation composition reflects the presence or absence of color development of the pH indicator. Therefore, the aforementioned cooler can easily recognize whether the cooling state is in the target state (a state in which the object can be sufficiently cooled). In addition, the color of the cold preservation composition before and after freezing does not mainly reflect the color of the components themselves other than the pH indicator such as the aforementioned inorganic salt and thickener.

The composition for cold preservation in the second embodiment contains an inorganic salt and a thickener as components that affect its acidity. In addition, in the aforementioned cold preservation composition, the aforementioned inorganic salt is selected from a specific combination of acidic inorganic salt and monohydrogen phosphate, and the content of these inorganic salts is limited. For monohydrogen phosphate, the content is also limited relative to water and inorganic salt. And the ratio of the total content of the thickener to the pH indicator whose combination of the inorganic salt and the thickener has a pKa in a specific range. The aforementioned cold-keeping composition having such a structure can change color significantly and greatly depending on the color development of the pH indicator or the presence or absence of color development.

<Inorganic Salt> The above-mentioned inorganic salt in the second embodiment has a function as a component of the cooling agent, and the freezing temperature of the cooling composition is mainly determined according to the type and amount. In addition, the aforementioned inorganic salt is not a component of the aforementioned pH indicator, and precipitates as crystalline or amorphous (amorphous) when the cold preservation composition is frozen, and the presence or absence of the precipitation interferes with the color change of the cold preservation composition .

The composition for cold preservation in the second embodiment contains an acidic inorganic salt and monohydrogen phosphate whose aqueous solution is acidic as the inorganic salt.

[Acid inorganic salt] The aforementioned acidic inorganic salt in the second embodiment is not particularly limited, and may be appropriately selected depending on the purpose, and may be a non-hydrate or a hydrate. For example, the acidic inorganic salt in the second embodiment may include the same inorganic salts as the aforementioned acidic inorganic salt in the first embodiment, that is, the dihydrogen phosphate and inorganic salts other than the dihydrogen phosphate.

The aforementioned acidic inorganic salt contained in the composition for cold preservation in the second embodiment may be only one type or two or more types, and if there are two or more types, the combination and ratio thereof can be arbitrarily selected.

[Monohydrogen Phosphate] In the second embodiment, the above-mentioned monohydrogen phosphate-based phosphoric acid (H ₃ PO ₄ ) in which two hydrogen ions are replaced by cations may be non-hydrate or hydrate. The aforementioned monohydrogen phosphate is usually an alkaline salt whose aqueous solution is alkaline.

For example, the monohydrogen phosphate in the second embodiment may include: disodium hydrogen phosphate (Na ₂ HPO ₄ ), dipotassium hydrogen phosphate (K ₂ HPO ₄ ), calcium hydrogen phosphate (CaHPO ₄ ), etc. Hydrogen metal salt; diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ) and other non-metallic monohydrogen phosphate salts.

The monohydrogen phosphate contained in the composition for cold preservation in the second embodiment may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be arbitrarily selected.

[Other inorganic salts] In addition to the aforementioned acidic inorganic salts and monohydrogen phosphate, the composition for cold preservation in the second embodiment may contain other inorganic salts other than any of these as the aforementioned inorganic salts. The aforementioned other inorganic salts may be non-hydrates or hydrates.

As long as the effect of the present invention is not impaired, the aforementioned other inorganic salts in the second embodiment are not particularly limited. For example, there may be mentioned: a neutral inorganic salt whose aqueous solution is neutral, and a phosphoric acid whose aqueous solution is alkaline. Inorganic salts other than monohydrogen salts, etc.

For example, the neutral inorganic salt can be, for example, the same inorganic salt as the neutral inorganic salt in the first embodiment, preferably sodium chloride, potassium chloride, or sodium sulfate.

The basic inorganic salt other than the aforementioned monohydrogen phosphate is preferably an inorganic salt other than phosphate. For example, the same inorganic salt as the aforementioned basic inorganic salt other than the phosphate in the first embodiment can be mentioned. Ideally sodium carbonate or potassium carbonate.

The aforementioned other inorganic salt contained in the composition for cold preservation in the second embodiment may be only one type or two or more types, and if it is two or more types, the combination and ratio of these can be arbitrarily selected.

In the composition for cold preservation in the second embodiment, preferable examples include a composition for cold preservation containing dihydrogen phosphate and neutral inorganic salt which are the aforementioned acidic inorganic salts. This cold preservation composition takes less time to complete the discoloration before and after freezing, and has more desirable properties.

When the composition for cold preservation in the second embodiment contains dihydrogen phosphate and neutral inorganic salt, the neutral inorganic salt is preferably sodium chloride or potassium chloride. By using such a neutral inorganic salt in combination, the composition for cold preservation in the second embodiment completes discoloration in a shorter time before and after freezing.

When the cold preservation composition in the second embodiment contains dihydrogen phosphate and neutral inorganic salt, the ratio of the content of the neutral inorganic salt to the total content of the inorganic salt is preferably 40-60% by mass, more preferably It is 43~57% by mass, particularly preferably 46~54% by mass. By setting the aforementioned ratio within this range, the composition for cold preservation in the second embodiment completes discoloration in a shorter time before and after freezing, and the color change is greater.

When the cold preservation composition in the second embodiment contains dihydrogen phosphate and neutral inorganic salt, the ratio of the content (mass) of the dihydrogen phosphate to the content (mass) of the monohydrogen phosphate ([cold preservation composition The content of dihydrogen phosphate (mass)]/[the content of monohydrogen phosphate (mass) of the cold preservation composition]) is preferably 0.04~2, more preferably 0.04~1.6, especially 0.04 ~1.4. By setting the aforementioned ratio within such a range, the cold-keeping composition in the second embodiment completes discoloration in a shorter time before and after freezing. Furthermore, since the cold preservation composition in the second embodiment changes more in color before and after freezing, the aforementioned ratio is preferably 0.04 to 1.2, more preferably 0.07 to 0.8, and particularly preferably 0.1 to 0.6.

In the cold preservation composition of the second embodiment, the ratio of the total content of the acidic inorganic salt and the monohydrogen phosphate to the total content of the inorganic salt is 5-100% by mass, preferably 5.5-100 Mass%, more preferably 6-100 mass%. By making the said ratio more than the said lower limit, the color change of the composition for cold preservation before and after freezing becomes large. In such a numerical range, the lower limit of the aforementioned ratio can be selected from, for example, 10% by mass, 20% by mass, 30% by mass, 40% by mass, and 45% by mass, but it is not limited to these. In addition, in such a numerical range, the upper limit of the ratio can be selected from, for example, 90% by mass, 80% by mass, 75% by mass, 70% by mass, 65% by mass, etc. However, it is not limited to these.

Before freezing in the second embodiment, it is preferable that the dissolved amount of the aforementioned inorganic salt in the composition for cold preservation at a temperature of 0°C or higher is as large as possible. The dissolved amount of the aforementioned inorganic salt is preferably 90 Mass% or more, preferably 95 mass% or more, more preferably 98 mass% or more, or 100 mass% (full amount). Furthermore, in the composition for cold preservation after freezing in the second embodiment, the more the amount of precipitation of the aforementioned inorganic salt, the better, and the amount of precipitation of the total amount of the aforementioned inorganic salt is preferably 90% by mass or more, which is more preferable It is 95% by mass or more, more preferably 98% by mass or more, or 100% by mass (all).

The total content of the inorganic salt in the cold preservation composition in the second embodiment is preferably 5 to 35 mass%, more preferably 5 to 30 mass%, and more preferably 10 to 30 mass%. For example, It can be 15-25% by mass.

<Thickener> The thickener in the second embodiment increases the consistency of the composition for cold preservation and is not a component of the pH indicator. The aforementioned thickener in the second embodiment is preferably a thickener that does not precipitate when the composition for cold preservation is frozen. In addition, in this specification, "the thickener does not precipitate when the cold preservation composition is frozen" is as described in the first embodiment.

For example, the thickener in the second embodiment may be the same thickener as the thickener in the first embodiment. As in the first embodiment, the aforementioned thickener in the second embodiment is preferably selected from acrylic polymers, carboxyalkyl cellulose, xanthan gum, guar gum, and hydroxyalkyl guar gum. , Pectin, tamarind gum, carrageenin and alkanediol constitute one or more of the group. In addition, the aforementioned thickener is more preferably one or more selected from the group consisting of acrylic polymer, carboxyalkyl cellulose, xanthan gum, guar gum, and hydroxyalkyl guar gum. By using such a thickener, the color change of the cold preservation composition before and after freezing is large, and the handling properties are more excellent.

The thickener contained in the composition for cold preservation in the second embodiment may be only one type or two or more types, and if there are two or more types, the combination and ratio can be arbitrarily selected.

In the cold preservation composition before and after freezing in the second embodiment, the smaller the amount of thickening agent precipitated, the better. The amount of precipitated thickener is preferably 10% by mass or less in the total amount of thickener. It is desirably 5% by mass or less, more desirably 2% by mass or less, and particularly desirably 0% by mass (all unprecipitated).

The thickener content of the composition for cold preservation in the second embodiment is preferably 0.1 to 10% by mass, more preferably 0.3 to 6% by mass, and particularly preferably 0.6 to 3% by mass.

In the cold preservation composition of the second embodiment, the ratio of the content of the monohydrogen phosphate to the total content of water, the aforementioned inorganic salt, and the thickener is 0.2 to 5.0% by mass, preferably 0.23 to 4.9 The mass% is more preferably 0.26 to 4.8 mass %. By setting the aforementioned ratio within such a range, the color change of the cold preservation composition before and after freezing becomes larger.

<pH indicator> The aforementioned pH indicator (acid-base indicator) in the second embodiment is a component that reflects the presence or absence of color development and determines the color of the cold-keeping composition. By containing a pH indicator, the cold preservation composition changes color before and after freezing.

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 stated, the pKa of the pH indicator in this embodiment means the value when the solvent is water and the temperature is 25°C. For example, the aforementioned pH indicator in the second embodiment may include the same pH indicator as the pH indicator in the first embodiment.

For example, the pH indicator in the second embodiment should preferably have a discoloration zone (pH) in the range of 3.0 to 9.0, more preferably in the range of 4.0 to 8.5, and particularly preferably in the range of 4.5 to 8.0 Within the range.

The pH indicator contained in the composition for cold preservation in the second embodiment may be only one type or two or more types, and if there are two or more types, the combination and ratio can be arbitrarily selected. However, in general, it is desirable to contain only one pH indicator.

As long as it is a color change that can achieve the goal of the cold preservation composition, the pH indicator content of the cold preservation composition in the second embodiment is not particularly limited. However, it is preferably 1 to 30 ppm, and more preferably 5~20ppm.

<Other components> In addition to water, an inorganic salt, a thickener, and a pH indicator, the composition for cold preservation in the second embodiment may contain other components other than these within a range that does not impair the effects of the present invention. Examples of the aforementioned other components include: solvents other than water as in the case of the first embodiment; various known additives such as preservatives and surfactants. The aforementioned other components contained in the composition for cold preservation in the second embodiment may be one type or two or more types, and if there are two or more types, the combinations and ratios can be arbitrarily selected.

The content of the aforementioned other components of the composition for cold preservation in the second embodiment is the same as the content of the other components of the composition for cold preservation in the first embodiment.

For example, in the cold preservation composition of 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, more preferably 5% by mass or less, It is particularly desirable that it is 2% by mass or less. In addition, the content of the preservative in the composition for cold preservation in the second embodiment is not particularly limited, but it is preferably 0.02 to 0.5 mass%, and more preferably 0.04 to 0.2 mass%. The composition for cold preservation in the second embodiment, with respect to the total content of water and components other than the solvent (the inorganic salt, thickener, pH indicator, and other components other than the solvent), the inorganic salt, thickening The ratio of the total content of the agent and the pH indicator is preferably 90% by mass or more, more preferably 93% by mass or more, more preferably 96% by mass or more, particularly preferably 98% by mass or more, or 100% by mass %. By making the ratio of the aforementioned total content more than the aforementioned lower limit, the color change of the cold preservation composition before and after freezing is greater.

The pH of the cold preservation composition in the second embodiment is preferably 4.7 to 8.0, more preferably 5.0 to 7.7, and particularly preferably 5.2 to 7.5. The composition for cold preservation in the second embodiment preferably has a pH in the aforementioned numerical range at the temperature at which the pH indicator is dissolved in the composition for cold preservation. More preferably, the temperature of the composition for cold preservation is 25°C. The pH of the aforementioned numerical range is displayed. In addition, in the present embodiment, unless otherwise stated in advance, the description of the composition for cold preservation simply "pH" means the pH of the composition for cold preservation itself.

The pH (α2) of the composition for cold preservation in the second embodiment when water is substituted for all components other than the inorganic salt and water is preferably 4.7 to 8.0, and more preferably 5.2 to 7.5. The pH (α2) is equivalent to the pH of water containing inorganic salts (for example, an aqueous solution of inorganic salts). The water containing inorganic salts contains only the aforementioned inorganic salts, and the content (mass%) is the same as the content (mass%) in the aforementioned cold preservation composition )the same. pH (α2) is an index of the acidity of the inorganic salt used in the aforementioned cold preservation composition. The pH (α2) is preferably the pH at the temperature at which the pH indicator is dissolved in the composition for cold preservation, and more preferably the pH when the water containing the inorganic salt is 25°C.

The pH (α3) of the composition for cold preservation in the second embodiment when replacing all components other than the thickener and water with water is preferably 6.0 to 9.1, and more preferably 6.5 to 8.6. The pH (α3) corresponds to the pH of water containing a thickener (for example, an aqueous solution of a thickener). The water containing a thickener contains only the aforementioned thickener, and the content (% by mass) is the same as that of the aforementioned cold preservation composition The content (mass %) is the same. The pH (α3) is an index of acidity of the thickener used in the aforementioned cold preservation composition. The pH (α3) is preferably the pH at the temperature at which the pH indicator is dissolved in the composition for cold preservation, and more preferably the pH at which the thickener-containing water is 25°C.

The composition for cold preservation in the second embodiment is produced by the same method as the composition for cold preservation in the above-mentioned first embodiment except for the difference in the blending components.

The cold insulation device related to the second embodiment of the present invention is provided with the aforementioned cold insulation composition, and can be made into the same structure as the cold insulation device related to the first embodiment described above except for the difference in the cold insulation composition. Except for the use of the aforementioned composition for cold preservation, the cold preservation tool related to the second embodiment of the present invention can be produced by the same method as the cold preservation tool related to the first embodiment described above.

The composition for cold preservation in the second embodiment greatly changes color before and after freezing, and therefore, the presence or absence of freezing can be easily recognized. In addition, the discoloration of the cold preservation composition can be recognized from the outside of the cold preservation device. Thereby, it can be easily recognized whether the cold storage device is sufficiently cooled to the desired temperature. In addition, even if the composition for cold preservation is repeatedly cooled and heated, such as repeated freezing and thawing, the effect will not be impaired. Therefore, the cold preservation appliance provided with the aforementioned composition for cold preservation is also suitable for repeated use.

<<Third Embodiment>> The cold storage device according to the third embodiment of the present invention is provided with a cold insulation composition containing water, an inorganic salt, a thickener, and a pH indicator; the aforementioned cold insulation composition contains An acidic inorganic salt whose aqueous solution is acidic is used as the aforementioned inorganic salt; in the aforementioned cold-keeping composition, the ratio of the content of the aforementioned acidic inorganic salt to the total content of the aforementioned inorganic salt is 5-100% by mass; the aforementioned cold-keeping composition The pH (α2) when water is used to replace all the ingredients other than the inorganic salt and water is 7 or less; the pH (α2) of the cold preservation composition when water is used to replace all the ingredients other than the thickener and water. α3) is 7 or more; pH(α2) and pH(α3) will be different from each other in the three pH ranges lower than the pH of the discoloration zone of the aforementioned pH indicator, pH of the discoloration zone, and pH higher than the discoloration zone The value of the pH range.

The color of the cold-keeping composition of the aforementioned cold-preserving appliance changes significantly before and after the freezing of the cold-keeping composition. Here, the color of the cold preservation composition reflects the presence or absence of color development of the pH indicator. Therefore, the aforementioned cooler can easily recognize whether the cooling state is in the target state (a state in which the object can be sufficiently cooled). In addition, the color of the cold preservation composition before and after freezing does not mainly reflect the color of the components themselves other than the pH indicator such as the aforementioned inorganic salt and thickener.

The composition for cold preservation in the third embodiment contains an inorganic salt and a thickener as components that affect its acidity. In addition, in the aforementioned cold preservation composition, the aforementioned inorganic salt is selected from acidic inorganic salt, and its content is limited, and the acidity of the inorganic salt and thickening agent is limited, and then the combination of the inorganic salt and thickening agent has an appropriate discoloration zone The pH indicator is used. The aforementioned cold-keeping composition having such a structure can change color significantly and greatly depending on the color development of the pH indicator or the presence or absence of color development.

<Inorganic salt> The above-mentioned inorganic salt in the third embodiment has a function as a component of the cooling agent, and the freezing temperature of the cooling composition is mainly determined by the type and amount. In addition, the inorganic salt is not a component of the pH indicator, and precipitates as crystalline or amorphous (amorphous) when the cold preservation composition freezes, and the presence or absence of the precipitation interferes with the color change of the cold preservation composition.

The composition for cold preservation in the third embodiment contains an acidic inorganic salt whose aqueous solution is acidic as the inorganic salt.

[Acid inorganic salt] The aforementioned acidic inorganic salt in the third embodiment is not particularly limited, and may be appropriately selected depending on the purpose, and may be a non-hydrate or a hydrate. For example, among the acidic inorganic salts in the third embodiment, it is desirable to include the same inorganic salts as the inorganic salts other than the 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),} etc., it is preferable It is ammonium chloride.

The aforementioned acidic inorganic salt contained in the composition for cold preservation in the third embodiment may be only one type or two or more types, and if there are two or more types, the combination and ratio can be arbitrarily selected.

[Other inorganic salts] In addition to the aforementioned acidic inorganic salts, the composition for cold preservation in the third embodiment may contain other inorganic salts as the aforementioned inorganic salts. The aforementioned other inorganic salts may be non-hydrates or hydrates.

As long as the effect of the present invention is not impaired, the aforementioned other inorganic salts in the third embodiment are not particularly limited. For example, there are neutral inorganic salts whose aqueous solution is neutral, and alkali whose aqueous solution is alkaline. Inorganic salts and so on.

For example, the neutral inorganic salt can be, for example, the same inorganic salt as the neutral inorganic salt in the first embodiment, preferably sodium chloride or potassium chloride.

The above-mentioned basic inorganic salt is preferably an inorganic salt other than phosphate and monohydrogen phosphate. For example, the same inorganic salt as the above-mentioned basic inorganic salt other than phosphate in the first embodiment can be mentioned. The one is sodium carbonate or potassium carbonate.

The aforementioned other inorganic salt contained in the composition for cold preservation in the third embodiment may be only one type or two or more types, and if there are two or more types, the combination and ratio thereof can be arbitrarily selected.

In the cold preservation composition of the third embodiment, the ratio of the content of the acidic inorganic salt to the total content of the inorganic salt is 5-100% by mass. For example, it can be made into 20-80% by mass, 40% by mass. ~60% by mass, etc. However, it is not limited to these. In such a numerical range, in addition to the above-mentioned 20% by mass and 40% by mass, the lower limit of the aforementioned ratio can also be selected from, for example, 10% by mass, 30% by mass, and 45% by mass. In addition, in such a numerical range, in addition to the above-mentioned 80% by mass and 60% by mass, the upper limit of the ratio can also be selected from 90% by mass, 70% by mass, 55% by mass, etc. However, it is not limited to these .

Before freezing in the third embodiment, it is preferable that the dissolved amount of the aforementioned inorganic salt in the composition for cold preservation at 0°C or higher is as large as possible, and the dissolved amount of the aforementioned inorganic salt is preferably 90 Mass% or more, preferably 95 mass% or more, more preferably 98 mass% or more, or 100 mass% (full amount). In addition, in the composition for cold preservation after freezing in the third embodiment, the more the amount of precipitation of the aforementioned inorganic salt, the better, and the amount of precipitation of the total amount of the aforementioned inorganic salt is preferably 90% by mass or more, which is more preferable It is 95% by mass or more, more preferably 98% by mass or more, or 100% by mass (all).

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

<Thickener> The thickener in the third embodiment increases the consistency of the cold-keeping composition and is not a component of the pH indicator. The aforementioned thickener in the third embodiment is preferably a thickener that does not precipitate when the composition for cold preservation is frozen. In addition, in this specification, "the thickener does not precipitate when the cold preservation composition is frozen" is as described in the first embodiment.

For example, the thickener in the third embodiment may be the same thickener as the thickener in the first embodiment. As in the first embodiment, the aforementioned thickener in the third embodiment is preferably selected from acrylic polymers, carboxyalkyl cellulose, xanthan gum, guar gum, and hydroxyalkyl guar gum. , Pectin, tamarind gum, carrageenin and alkanediol constitute one or more of the group. In addition, the aforementioned thickener is more preferably one or more selected from the group consisting of acrylic polymer, carboxyalkyl cellulose, xanthan gum, guar gum, and hydroxyalkyl guar gum. By using such a thickener, the color change of the cold preservation composition before and after freezing is large, and the handling properties are more excellent.

The thickener contained in the composition for cold preservation in the third embodiment may be one type or two or more types, and if there are two or more types, the combination and ratio of these can be arbitrarily selected.

In the composition for cold preservation before freezing and after freezing in the third embodiment, the smaller the amount of thickener precipitated, the better. The amount of thickener precipitated is preferably 10% by mass or less in the total amount of thickener. It is desirably 5% by mass or less, more desirably 2% by mass or less, and particularly desirably 0% by mass (all unprecipitated).

The thickener content of the composition for cold preservation in the third embodiment is preferably 0.1-10% by mass, more preferably 0.3-6% by mass, and particularly preferably 0.6-3% by mass.

<pH indicator> The aforementioned pH indicator (acid-base indicator) in the third embodiment is a component that reflects the presence or absence of color development and determines the color of the cold-keeping composition. By containing a pH indicator, the cold preservation composition changes color before and after freezing.

The aforementioned pH indicator in the third embodiment is not particularly limited, but the pKa is preferably 4.0 to 7.5. In addition, unless otherwise stated, the pKa of the pH indicator in this embodiment means the value when the solvent is water and the temperature is 25°C. For example, the aforementioned pH indicator in the third embodiment may include the same pH indicator as the pH indicator in the first embodiment.

For example, the pH indicator in the third embodiment should preferably have a discoloration zone (pH) in the range of 3.0 to 10.5, more preferably in the range of 3.3 to 9.5, and particularly preferably in the range of 3.5 to 9.0. Within the range.

The pH indicator contained in the composition for cold preservation in the third embodiment may be only one type or two or more types, and if it is two or more types, the combination and ratio of these can be arbitrarily selected. However, in general, it is desirable to contain only one pH indicator.

As long as it is a color change that can achieve the goal of the cold-keeping composition, the content of the pH indicator in the cold-keeping composition in the third embodiment is not particularly limited. However, it is preferably 1 to 30 ppm, and more preferably 5~20ppm.

<Other components> In addition to water, an inorganic salt, a thickener, and a pH indicator, the composition for cold preservation in the third embodiment may contain other components other than these within a range that does not impair the effects of the present invention. Examples of the aforementioned other components include: solvents other than water as in the case of the first embodiment; various known additives such as preservatives and surfactants. The aforementioned other components contained in the composition for cold preservation in the third embodiment may be only one type or two or more types, and if there are two or more types, the combinations and ratios can be arbitrarily selected.

The content of the aforementioned other components of the composition for cold preservation in the third embodiment is the same as the content of the other components of the composition for cold preservation in the first embodiment.

For example, in the cold preservation composition of 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 more preferably 5% by mass or less, It is particularly desirable that it is 2% by mass or less. In addition, the content of the preservative in the composition for cold preservation in the third embodiment is not particularly limited. However, it is preferably 0.02 to 0.5 mass%, and more preferably 0.04 to 0.2 mass%. The composition for cold preservation in the third embodiment, relative to the total content of water and components other than the aforementioned solvent (the aforementioned inorganic salt, thickener, pH indicator, and other components other than the aforementioned solvent), the aforementioned inorganic salt, thickening The ratio of the total content of the agent and the pH indicator is preferably 90% by mass or more, more preferably 93% by mass or more, more preferably 96% by mass or more, particularly preferably 98% by mass or more, or 100% by mass %. By making the ratio of the aforementioned total content more than the aforementioned lower limit, the color change of the cold preservation composition before and after freezing is greater.

The composition for cold preservation in the third embodiment has a pH (α2) of 7 or less when replacing all components other than the inorganic salt and water with water. The pH (α2) is equivalent to the pH of water containing inorganic salts (for example, an aqueous solution of inorganic salts). The water containing inorganic salts contains only the aforementioned inorganic salts, and the content (mass%) is the same as the content (mass%) in the aforementioned cold preservation composition )the same. pH (α2) is an index of the acidity of the inorganic salt used in the aforementioned cold preservation composition. The pH (α2) is preferably 3.5 to 7.0, more preferably 4.0 to 6.6, and particularly preferably 4.5 to 6.3.

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

The composition for cold preservation in the third embodiment has a pH (α3) of 7 or more when water is substituted for all the components other than the thickener and water. The pH (α3) corresponds to the pH of water containing a thickener (for example, an aqueous solution of a thickener). The water containing a thickener contains only the aforementioned thickener, and the content (% by mass) is the same as that of the aforementioned cold preservation composition The content (mass %) is the same. The pH (α3) is an index of acidity of the thickener used in the aforementioned cold preservation composition. The pH (α3) is preferably 7.0~9.5, more preferably 7.0~9.0, and especially ideal is 7.0~8.5.

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

The composition for cold preservation in the third embodiment has pH (α2) and pH (α3) in three pH ranges lower than the pH of the discoloration zone of the aforementioned pH indicator, pH of the discoloration zone, and pH higher than the pH of the discoloration zone , Display the values of different pH ranges.

The pH of the cold preservation composition in the third embodiment is preferably 4.1 to 7.4, more preferably 4.4 to 7.1, and particularly preferably 4.6 to 6.9. The composition for cold preservation in the third embodiment preferably shows a pH in the aforementioned numerical range at the temperature at which the pH indicator is dissolved in the composition for cold preservation, and more preferably, when the temperature of the composition for cold preservation is 25°C The pH of the aforementioned numerical range is displayed. In addition, in the present embodiment, unless otherwise stated in advance, the description of the composition for cold preservation simply "pH" means the pH of the composition for cold preservation itself.

The composition for cold preservation in the third embodiment is produced by the same method as the composition for cold preservation in the above-mentioned first embodiment except for the difference in the blending components.

The cold insulation device related to the third embodiment of the present invention is provided with the aforementioned cold insulation composition, and can have the same structure as the cold insulation device related to the first embodiment described above except for the difference in the cold insulation composition. Except for the use of the aforementioned composition for cooling, the cooling tool according to the third embodiment of the present invention can be produced by the same method as the cooling tool according to the first embodiment described above.

The composition for cold preservation in the third embodiment greatly changes color before and after freezing, so the presence or absence of freezing can be easily recognized. In addition, the discoloration of the cold preservation composition can be recognized from the outside of the cold preservation device. Thereby, it can be easily recognized whether the cold storage device is sufficiently cooled to the desired temperature. In addition, even if the composition for cold preservation is repeatedly cooled and heated, such as repeated freezing and thawing, the effect will not be impaired. Therefore, the cold preservation appliance provided with the aforementioned composition for cold preservation is also suitable for repeated use.

Examples Hereinafter, the present invention will be explained in more detail with specific examples. However, the present invention is not limited by the embodiments shown below at all.

The raw materials used in the examples and comparative examples are shown below. (Thickener)． HPG1 (Hydroxypropyl Guar): "MEYPRO HPG8111" manufactured by Sanjing Company. CMC (Carboxymethyl Cellulose): "CELLOGEN" manufactured by Daiichi Industrial Pharmaceutical Co., Ltd. CVP (Carboxy Vinyl Polymer): "RHEOGIC270" (pH indicator) manufactured by Toagosei Co., Ltd. BCP: Bromocresol Purple (manufactured by Wako Pure Chemical Industries, Ltd.). PR: Phenol Red (manufactured by Wako Pure Chemical Industries, Ltd.). BTB: Bromovanol Blue (manufactured by Wako Pure Chemical Industries, Ltd.). MR: Methyl Red (manufactured by Wako Pure Chemical Industries, Ltd.). BCG: Bromocresol green (manufactured by Wako Pure Chemical Industries, Ltd.) (preservative) "SODIUM OMADINE" manufactured by Sanai Petroleum Corporation

[Example 1] <Production of composition for cold preservation and cold preservation tool (first embodiment)> At room temperature (20-25°C), BCP was added to water (79.16 parts by mass) to dissolve it, and then , And then add 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) to dissolve them, and then, Add HPG1 (1.10 parts by mass) and stir at room temperature for 1 hour to dissolve it. After confirming that the prepared liquid is sufficiently thickened, add preservative (0.05 parts by mass), and place it in the room Stir it directly at low temperature for 30 minutes, thereby preparing a composition for cold preservation. At this time, the blending amount of BCP was adjusted so that the content in the obtained cold preservation composition was 8 ppm. Table 2 shows the contents of each blending component and the composition for cold preservation. In addition, in Table 2, the "alkaline salt" in the blending component column means alkaline salts other than phosphate and monohydrogen phosphate. In addition, the trisodium phosphate dodecahydrate system omits the description of crystal water (12H ₂ O). These are also the same in the table below.

In addition, Table 7 shows physical properties such as pH (α1), pH (α2), pH (α3), the pKa of the pH indicator when the solvent is water and the temperature is 25°C, and the pH of the cold preservation composition. The pH (α1), pH (α2), pH (α3) and the aforementioned pH are all measured by setting the temperature of the measurement object to 25°C. Table 7 also shows the ratio of the total content of acidic inorganic salt and phosphate to the total content of inorganic salt in the prepared cold preservation composition (hereinafter, this value may be represented by the symbol "(X1)" ).

Next, the prepared composition for cold preservation was enclosed in a container made of high-density polyethylene, and the cold preservation tool of 1st Embodiment was manufactured.

<Evaluation of the composition for cold storage> (Color change) The prepared composition for cold storage (cold insulation tool) was cooled to -25°C. In the meantime, the cold preservation composition is frozen at a temperature higher than -25°C, and the color changes before and after freezing. In addition, the color change of the cold preservation composition before and after the freezing was evaluated visually based on the following criteria. The results are shown in Table 9. Table 9 also shows the discoloration area and color change of the pH indicator used.

In addition, in Table 9, the "color change" described in the evaluation result column indicates the color change of the cold preservation composition before and after freezing. For example, "green→yellow" means that the color of the cold preservation composition before freezing It is green and yellow when frozen. ○: The color change before and after freezing is large, and the recognition of the cooling state is extremely easy. △: The color change before and after freezing can be discriminated, and the cooling state can be discerned. ×: The color change before and after freezing is unclear, and it is difficult or impossible to recognize the cooling state.

In addition, in Table 9, the "low pH→high pH color change" described in the column of the color change area of the pH indicator means that when the pH of the liquid containing the pH indicator changes from a specific value to a higher value, the pH indicator The color change displayed by the agent in the color changing area. For example, "yellow→violet" means that during the process of increasing the pH of the liquid, the pH indicator will change the color of the liquid from yellow to purple.

<Production of the cold-keeping composition and the cold-keeping device (first embodiment), and evaluation of the cold-keeping composition> [Examples 2 to 13] Except for the blending components of the cold-keeping composition and the components in the cold-keeping composition Except that the content was made as shown in Tables 2 and 3, by the same method as in Example 1, the cold preservation composition and the cold preservation tool of the first embodiment were produced, and the cold preservation composition was evaluated. Each physical property of the composition for cold preservation is shown in Table 7, and the evaluation result is shown in Table 9.

[Example 14] <Production of composition for cold preservation and cold preservation tool (second embodiment)> At room temperature (20-25°C), BCP was added to water (78.90 parts by mass) to dissolve it, and then , Then add ammonium chloride (9.70 parts by mass), potassium chloride (9.70 parts by mass) and diammonium hydrogen phosphate (0.50 parts by mass) to dissolve them, and then add CMC (1.10 parts by mass), and at room temperature Stir it directly for 1 hour to dissolve it. After confirming that the obtained liquid substance is sufficiently thickened, add a preservative (0.05 parts by mass), and stir directly at room temperature for 30 minutes to obtain a cold storage Use the composition. At this time, the blending amount of BCP was adjusted so that the content in the obtained cold preservation composition was 8 ppm. Table 3 shows the content of each blending component and the composition for cold preservation.

In addition, Table 7 shows physical properties such as pH (α1), pH (α2), pH (α3), the pKa of the pH indicator when the solvent is water and the temperature is 25°C, and the pH of the cold preservation composition. The pH (α1), pH (α2), pH (α3) and the aforementioned pH are all measured by setting the temperature of the measurement object to 25°C. Table 7 also shows the ratio of the total content of acidic inorganic salt and monohydrogen phosphate to the total content of inorganic salt in the cold preservation composition (hereinafter, sometimes represented by the symbol "(X2)" This value), and the ratio of the content of monohydrogen phosphate to the total content of water, inorganic salt and thickener (hereinafter, this value is sometimes represented by the symbol "(X3)").

Next, the prepared composition for cold preservation was enclosed in a container made of high-density polyethylene, and the cold preservation tool of 2nd Embodiment was manufactured.

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

<Production of the cold-insulation composition and the cold-insulation appliance (second embodiment), and evaluation of the cold-insulation composition> [Examples 15 to 33] Except for the blending components of the cold-insulation composition and the contents of the cold-insulation composition Except that the content was made as shown in Tables 3 to 5, by the same method as in Example 14, the cold preservation composition and the cold preservation tool of the second embodiment were produced, and the cold preservation composition was evaluated. The physical properties of the cold preservation composition are shown in Tables 7 to 8, and the evaluation results are shown in Table 9.

[Example 34] <Production of a composition for cold preservation and a cold preservation tool (third embodiment)> At room temperature (20-25°C), MR was added to water (79.35 parts by mass) to dissolve it, and then , And then add ammonium chloride (9.75 parts by mass) and potassium chloride (9.75 parts by mass) to dissolve them, and then add CMC (1.10 parts by mass), and stir directly at room temperature for 1 hour to dissolve it. After confirming that the obtained liquid substance is sufficiently thickened, a preservative (0.05 parts by mass) is added, and the mixture is directly stirred at room temperature for 30 minutes, thereby preparing a cold preservation composition. At this time, the blending amount of MR was adjusted so that the content in the obtained cold preservation composition was 8 ppm. Table 5 shows the contents of each blending component and the composition for cold preservation.

In addition, Table 8 shows physical properties such as pH (α1), pH (α2), pH (α3), the pKa of the pH indicator when the solvent is water and the temperature is 25°C, and the pH of the cold preservation composition. The pH (α1), pH (α2), pH (α3) and the aforementioned pH are all measured by setting the temperature of the measurement object to 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 prepared cold preservation composition (hereinafter, this value may be represented by the symbol "(X4)").

Next, the prepared composition for cold preservation was enclosed in a container made of high-density polyethylene to produce the cold preservation tool of the third embodiment.

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

<Production of the cold-keeping composition and the cold-keeping appliance (third embodiment), and evaluation of the cold-keeping composition> [Examples 35 to 37] Except for the blending components of the cold-keeping composition and the components in the cold-keeping composition Except that the content was made as shown in Table 5, by the same method as in Example 34, the cold preservation composition and the cold preservation tool of the third embodiment were produced, and the cold preservation composition was evaluated. The physical properties of the composition for cold preservation are shown in Table 8, and the evaluation results are shown in Table 9.

<Production of cold insulation composition and cold insulation equipment, and evaluation of cold insulation composition> [Comparative Examples 1 to 9] Except that the blending components of the cold insulation composition and the content in the cold insulation composition are made as shown in Table 5 and Except for the point shown in 6, by the same method as in Example 1, a cold-insulation composition and a cold-insulation tool were manufactured, and the cold-insulation composition was evaluated. The physical properties of the composition for cold preservation are shown in Table 8, and the evaluation results are shown in Table 9.

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

From the above results, it can be understood that the cold insulation device related to the first embodiment of the present invention (Examples 1 to 13), the cold insulation device related to the second embodiment (Examples 14 to 33), and the cold insulation device related to the third embodiment ( In Examples 34 to 37), the precipitation of inorganic salts when the cold preservation composition is frozen, reflects the color change of the pH indicator, and the cold preservation composition clearly changes in color before and after freezing, which can be easily Identify the cooling state.

Among the cold insulation devices related to the first embodiment, particularly the cold insulation devices of Examples 1 to 3, 8 to 11, and 13, the time required for the cold insulation composition to complete discoloration is short, and it exhibits particularly desirable properties.

Among the cold insulation appliances according to the second embodiment, particularly in the cold insulation appliances of Examples 22 to 27, the time required for the cold insulation composition to complete discoloration is short, and it exhibits particularly desirable properties. This means that when the cold preservation composition contains dihydrogen phosphate and neutral inorganic salt, it tends to show such desirable properties.

In contrast, in the cold preservation devices of Comparative Examples 1 to 9, the composition for cold preservation is different from the composition for cold preservation of the above-mentioned examples, the color change before and after freezing is not clear, and it is difficult or impossible to recognize the cooling state.

<Production of the cold-insulation composition and the cold-insulation appliance (first embodiment), and evaluation of the cold-insulation composition> [Examples 38 to 40] Except for the blending components of the cold-insulation composition and the components in the cold-insulation composition Except that the content was made as shown in Table 10, by the same method as in Example 1, the cold preservation composition and the cold preservation tool of the first embodiment were produced, and the cold preservation composition was evaluated. Each physical property of the composition for cold preservation is shown in Table 11, and the evaluation result is shown in Table 12.

<Manufacturing of the cold preservation composition and the cold preservation tool (second embodiment), and evaluation of the cold preservation composition> [Examples 41 to 46] Except for the blending components of the cold preservation composition and the content of the cold preservation composition Except that the content was made as shown in Table 10, by the same method as in Example 14, the cold preservation composition and the cold preservation tool of the second embodiment were produced, and the cold preservation composition was evaluated. Each physical property of the composition for cold preservation is shown in Table 11, and the evaluation result is shown in Table 12.

[Table 10]

[Table 11]

[Table 12]

As mentioned above, in the cold insulation device related to the first embodiment of the present invention (Examples 38 to 40) and the cold insulation device related to the second embodiment (Examples 41 to 46), both of them will follow when the cold insulation composition freezes. The precipitation of the inorganic salt reflects the color change of the pH indicator, and the color of the cold preservation composition changes clearly before and after the freezing, and the cooling state can be easily recognized.

Industrial Applicability The present invention can be used as a cold storage device for various fresh products.

Claims (7)

A cold-preserving appliance comprising a cold-preserving composition containing water, an inorganic salt, a thickener, and a pH indicator; the aforementioned cold-preserving composition contains an acidic inorganic salt and phosphate whose aqueous solution is acidic as the inorganic Salt; In the composition for cold preservation, the ratio of the total content of the acidic inorganic salt and phosphate relative to the total content of the inorganic salt is 5-100% by mass; The composition for cold preservation contains dihydrogen phosphate and phosphoric acid Inorganic salts other than dihydrogen salts are used as the aforementioned acidic inorganic salts; the pH indicator of the aforementioned pH indicator has a pKa of 4.9 to 8.0; the aforementioned cold preservation composition has a pH ( α1) The aforementioned pKa satisfies the relationship shown in the following formula (i): pKa of the pH indicator≦pH(α1)≦pKa of the pH indicator+1.8‥‥(i). Such as the cold preservation appliance of claim 1, wherein the pH of the aforementioned composition for cold preservation is 4.6~8.8. The cold preservation appliance of claim 1 or 2, wherein the composition for cold preservation has a pH (α3) of 6.0 to 8.5 when water is used to replace all components other than the thickener and water. A cold-preserving appliance comprising a cold-preserving composition containing water, an inorganic salt, a thickener, and a pH indicator; the aforementioned cold-preserving composition contains an acidic inorganic salt and a monohydrogen phosphate whose aqueous solution is acidic as The aforementioned inorganic salt; In the aforementioned cold preservation composition, the ratio of the total content of the aforementioned acidic inorganic salt and monohydrogen phosphate relative to the total content of the aforementioned inorganic salt is 5-100% by mass; In the aforementioned cold preservation composition, The ratio of the content of monohydrogen phosphate to the total content of water, the aforementioned inorganic salt and thickener is 0.2~5.0% by mass; the pKa of the aforementioned pH indicator is 4.9~8.0. Such as the cold preservation appliance of claim 4, wherein the pH of the aforementioned composition for cold preservation is 4.7~8.0. Such as claim 4 or 5, wherein the cold preservation composition has a pH (α3) of 6.0 to 9.1 when water is used to replace all components other than the thickener and water. A cold preservation appliance comprising a cold preservation composition containing water, an inorganic salt, a thickener, and a pH indicator; the aforementioned cold preservation composition contains an acidic inorganic salt whose aqueous solution is acidic as the aforementioned inorganic salt; In the aforementioned cold preservation composition, the ratio of the content of the aforementioned acidic inorganic salt to the total content of the aforementioned inorganic salt is 5-100% by mass; the aforementioned cold preservation composition substitutes water for all the contents other than the aforementioned inorganic salt and water The pH (α2) of the ingredients is 7 or less; The cold preservation composition has a pH (α3) of 7 or more when water is used to replace the thickener and all ingredients other than water; pH(α2) and pH(α3) ) Is in the three pH ranges lower than the pH of the discoloration zone of the aforementioned pH indicator, pH of the discoloration zone, and pH higher than the pH of the discoloration zone, showing values in different pH ranges.