JP2011256280A - Gelatine crosslinked gel-based cooling and heating medium, and cold and heat-retaining material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling and heating medium enabling the cost to be reduced by increasing the amount of water contained in the cooling and heating medium, capable of heightening cold and heat-retaining effects by increasing the heat capacity and elongating a cold and heat-retaining time, hardly causing separation of the water even after repeated cooling or heating cycles, and capable of elongating a repeatedly used time, and to provide a cold and heat-retaining material using the medium.SOLUTION: The cooling and heating medium 2 contains a crosslinked gelatine and a gelatine-crosslinked gel containing the water. A granular or pulverized product is used as the gelatin-crosslinked gel. The cold and heat-retaining material 1 is obtained by storing the cooling and heating medium 2 composed of the gelatine-crosslinked gel containing 2-60 wt.% of the crosslinked gelatine and 40-98 wt.% of the water, and having 9-3,000 g of jelly strength in a flexible container 3.

Description

  The present invention relates to a gelatin-crosslinked gel-based cooling medium, particularly a cooling medium used for cooling or heating by storing heat, and a cold insulation heat material for keeping cold or keeping warm by this cooling medium.

  As a cold insulation material to be put in an ice pillow, ice bag, cold insulation container, or a heat insulation material such as a hot water tampo or a squirrel furnace, a cold insulation heat material in which a cold heat medium is contained in the container is used. Water having a large heat capacity is used as a cooling medium for keeping cold or keeping warm, but in order to keep cold or keeping warm, a thickener such as CMC (carboxymethylcellulose) is added to the water to make it viscous. A cooling medium with increased heat resistance is used. In other words, in a low viscosity medium such as water, convection occurs and heat leaks unnecessarily, and in order to prevent this, convection is prevented by using a cooling medium whose viscosity is increased by a thickener, and this is maintained. The cooling effect is enhanced and the heat retention time is maintained. However, in order to increase the viscosity to such an extent that convection can be prevented, it is necessary to add a large amount of a thickener such as CMC, which increases the cost, reduces the amount of water with high heat capacity, and reduces the overall heat capacity. Get smaller.

  In addition, a pack-shaped cold insulation material containing such a cold medium in a container is used as a cold insulation material in a state of being frozen in a refrigerator or freezer, or immersed in hot water, or in some cases microwaved in a microwave oven. Used as a heat insulating material by heating. However, when such a cold insulation heat material is used, if the cooling or heating cycle is repeated, the aqueous phase and the thickener phase are separated, and the cold insulation heat effect is lowered. In particular, when frozen and used as a cold insulation material, ice crystals grow by freezing, so when melted, water separates like agar, frozen tofu, etc., and does not return to the original viscous solution, reducing the heat insulation effect To do.

  In addition, a pack-shaped cold insulation material that contains such a cooling medium in a container is a container composed of a thin sheet such as a resin film bag, but when used for cooling or heating the human body, etc. Because it is cooled and heated through the thin sheet as described above, it cannot be raised to a very high temperature, and in the case of freezing, it cannot be hardened and deformed, and it cannot be used directly by hitting the human body. There are also problems such as bad.

  Patent Document 1 (Japanese Patent Laid-Open No. 2008-156582) proposes a cold-retaining agent having a gel-like form in which water is absorbed in a crosslinked sodium polyacrylate high water-absorbing polymer. This is what absorbs water in a superabsorbent resin and uses it as a heat medium, and can increase the amount of water absorbed in the resin, but when the cooling or heating cycle is repeated, the water phase and the resin are separated, Cooling heat effect is reduced. This point is not much different from the case of using a conventional thickener, and the same is true when it is used as a heat retaining medium. This phenomenon is presumed to be due to the separation of water from the resin because the water dispersed in the resin with a cross-linked structure flows due to cooling or heating, and especially ice crystals grow in the case of freezing. Like the above, it does not return to the dispersed state in the original cross-linked structure, and the heat insulation heat effect is reduced.

In Patent Document 2 (Japanese Patent Application Laid-Open No. 2008-156588), a gel body is formed by adding a gelling thickener derived from a natural product such as agar, carrageenan, gelatin, and CMC to a saccharide such as a starch degradation product. A cryogen has been proposed. Here, gelatin is said to be used as a gel-forming agent, but this is only used as a thickening agent like agar, carrageenan and CMC, and no use of cross-linked gelatin is shown. For this reason, the cold-retaining agent obtained here is essentially the same as that using a thickener such as a conventional CMC, and the cost increases and the cold-retaining heat effect is low.

JP2008-156582 JP2008-156588

  The object of the present invention is to increase the amount of water contained in the cooling medium, thereby reducing the cost, increasing the heat capacity and extending the cooling heat time, and increasing the cooling heat effect. It is to provide a cooling medium capable of extending the repeated use time without water separating even after repeated cooling or heating cycles, and a cold insulation heat material using the same.

The present invention is the following cooling medium and cold insulation material.
(1) A cold medium containing a gelatin crosslinked gel containing crosslinked gelatin and water.
(2) A cold medium containing a granulated or pulverized product of gelatin cross-linked gel containing cross-linked gelatin and water.
(3) The cooling medium as described in (1) or (2) above, wherein the gelatin crosslinked gel contains 2 to 60% by weight of crosslinked gelatin and 40 to 98% by weight of water, and has a jelly strength of 9 to 3000 g.
(4) In any one of the above (1) to (3), the gelatin crosslinked gel is a reaction product of an aqueous sol containing 2 to 59% by weight of gelatin, 1 to 20% by weight of a crosslinking agent and 40 to 97% by weight of water. A cold medium having a jelly strength of 9 to 3000 g.
(5) The cooling medium according to (4), wherein the gelatin has a molecular weight of 10,000 to 500,000.
(6) The cooling medium according to (4) or (5), wherein the crosslinking agent is an ethylenically unsaturated compound-maleic anhydride copolymer, a ring-opened product thereof, or a salt thereof.
(7) A cold insulation material in which a cold heat medium containing a gelatin crosslinked gel containing the crosslinked gelatin and water according to any one of (1) to (6) is contained in a container.
(8) A cold insulation material in which a cold medium containing a granulated or pulverized product of a gelatin crosslinked gel containing the crosslinked gelatin and water according to any one of (2) to (6) is housed in a soft container.
(9) The cold insulation material according to (7) or (8) above, wherein the container is a heat-resistant, microwave-permeable container.

  The gelatin crosslinked gel constituting the cooling medium of the present invention is an aqueous gelatin crosslinked gel containing crosslinked gelatin and water. Cross-linked gelatin is obtained by three-dimensionally cross-linking gelatin with a cross-linking agent to form a three-dimensional network structure. Gelatin is a denatured collagen in which the helical structure of collagen, which is a protein in higher animals, is broken, and is a linear polypeptide. By cross-linking this with a cross-linking agent, a three-dimensional network structure is formed. The Gelatin has a high affinity with water and dissolves very well in water, but cross-linked gelatin is similar and absorbs large amounts of water. Moreover, it has a high affinity with water, and it does not separate even after repeated cooling or heating cycles, and can be used repeatedly for a long period of time.

Gelatin cross-linked gel contains 2-60 wt% cross-linked gelatin, preferably 3-50 wt%, and 40-98 wt% water, preferably 50-97 wt%, and has a jelly strength of 9-3000 g, preferably 30-2000 g. Are preferred. The gel jelly strength is displayed as the load (g) required to push down the surface of the gel by 4 mm with a probe having a diameter of 12.7 mm according to JIS K 6503 (2001). In the case of, correct by increasing the diameter of the probe. Such gelatin cross-linked gels are gelatin 2-5.
Reacting an aqueous sol containing 9% by weight, preferably 4 to 59% by weight, 1 to 20% by weight of a crosslinking agent, preferably 2 to 20% by weight, and 40 to 97% by weight, preferably 50 to 95% by weight of water. The reaction product can be used as a gelatin cross-linked gel.

In the present invention, gelatin used as a raw material for crosslinked gelatin has a molecular weight of 10,000 to 500,000, preferably 15,000 to 200,000, but may include those outside this range. . Such gelatin is obtained by denaturing collagen with heat, acid, alkali, enzyme, etc., but commercially available products can also be used. Since the molecular weight of gelatin varies depending on denaturation conditions, for example, the type and concentration of drugs and auxiliaries used for denaturation, temperature, time, and the like, gelatin having the desired molecular weight can be obtained by selecting denaturation conditions. The average molecular weight of gelatin can be determined by measuring the molecular weight distribution according to the Pagii method ninth edition (2002).
As can be seen from the fact that gelatin is used as an adhesive in glue, it has adhesiveness, but cross-linked gelatin that has been cross-linked with a cross-linking agent has reduced adhesiveness, and does not adhere when granulated or pulverized by crushing etc. Maintain shape independently of each other.

  Any crosslinking agent may be used as long as it can react with a functional group of gelatin to crosslink, but an ethylenically unsaturated compound-maleic anhydride copolymer, a ring-opening polymer thereof or a salt thereof is preferable. Examples of the ethylenically unsaturated compound include olefins such as ethylene, propylene, butene-1, butene-2, and isobutylene, and other compounds having an ethylenically unsaturated group. The ring-opening polymer is a polymer opened by adding water to an ethylenically unsaturated compound-maleic anhydride copolymer, and the salt thereof is a salt such as an ammonium salt or a sodium salt of the ring-opening polymer. The salt can be formed by reacting the above acid copolymer or ring-opening polymer with ammonium hydroxide, sodium hydroxide or the like.

  The ethylenically unsaturated compound-maleic anhydride copolymer is a copolymer of these ethylenically unsaturated compounds and maleic anhydride, and the molar ratio of the ethylenically unsaturated compound and maleic anhydride is 10: 1 to 1. 1:10, preferably 5: 1 to 1: 5, and the average molecular weight is usually 2,000 to 200,000, preferably 3,000 to 100,000. A commercially available product is used as such an ethylenically unsaturated compound-maleic anhydride copolymer. The ratio of ring-opening polymer, ammonium salt, sodium salt, or the like for ring-opening or conversion to a salt is arbitrary, but it is preferable to convert all of the anhydrous rings.

  The gelatin cross-linked gel may be made of a foam in which fine bubbles are dispersed, and such a foam can be produced by adding a foaming agent such as hydrogen peroxide together with a cross-linking agent to cause a reaction. The amount of the foaming agent such as hydrogen peroxide added is 1% by weight or less, preferably 0.05 to 0.8% by weight. The gelatin cross-linked gel may contain other components such as an antibacterial agent, a colorant, a fragrance, an organic solvent, and salts. The antibacterial agent is preferably one that is uniformly dispersed in the crosslinked gelatin. The organic solvent is mainly used as a solvent such as a crosslinking agent or an antibacterial agent, but can be omitted if it is water-soluble. Organic solvents, salts, and the like are sometimes used for freezing point depression, but these may not be used when using latent heat. The content of other components is 0 to 10% by weight, preferably about 0.1 to 5% by weight.

The gelatin cross-linked gel of the present invention is produced by reacting an aqueous sol containing these gelatin, a cross-linking agent and other components added as necessary. At this time, the gelatin and the cross-linking agent react and cross-link so as to embrace water and other components added as necessary, whereby an aqueous gel is formed. Such gelatin cross-linked gel can be produced by reacting the aqueous sol at 20 to 70 ° C., preferably at room temperature to 60 ° C. When a foaming agent is added and reacted, in the case of hydrogen peroxide, oxygen is liberated and foams, and a foam is formed. The gelatin cross-linked gel formed in this way is an aqueous gel in which gelatin is cross-linked with water and other components added as necessary. Even when the concentration of the gel forming agent is low, it has excellent shape retention. Alternatively, a pulverized product or other molded body can be formed.

  The cooling / heating medium of the present invention includes the above-mentioned crosslinked gelatin and gelatin-crosslinked gel containing water, and the form thereof may take any form such as a molded body having any shape, granulated or pulverized product, and powder. The formed body can be formed into any shape and size according to the purpose of use. The granulated or pulverized product may be a granulated product granulated at or after the formation of the gelatin cross-linked gel, or may be a pulverized product obtained by pulverizing the formed gelatin cross-linked gel. The granulated or pulverized product is a granule or granule having an arbitrary shape, and includes a crushed product and a pulverized product crushed into an irregular shape. The particle size of the granulated or pulverized product is not limited, but can typically be 0.5 to 20 mm. The amount of the crosslinking agent is selected and the jelly strength is adjusted so that these molded bodies, granulated or pulverized products, etc. maintain their respective shapes in a state of containing water.

  The cooling medium of the present invention can be used as it is as a cold insulation material in the state of gelatin crosslinked gel containing the above crosslinked gelatin and water depending on the form of use, but generally the above cooling medium is contained in a container. In this state, it can be used as a cold insulation heat material. When the cooling medium is a gelatin cross-linked gel molded article, it may be stored in a container after forming the molded body, and it may be used as a cold insulation material. Thus, a molded article of gelatin cross-linked gel can be formed. In the case of a granulated or pulverized product or powder, it is common to store the granulated or pulverized product or powder formed at the same time or after the reaction in a container to constitute a cold insulation material.

  The container for storing the cooling medium is appropriately selected depending on the purpose of use, but a resin bag, a bottle, a tank, or the like is selected. When this container is used as a cryogen, any material and shape can be used. However, when it is used as a heat insulator, a container made of a heat-resistant and microwave-permeable material is used. Preferably, this prevents the container itself from being heated and deteriorated even when microwave heating is performed in a microwave oven. Examples of the microwave permeable material include a low dielectric constant resin. Examples of the low dielectric constant resin include resins having a relative dielectric constant of 5 or less, preferably 3 or less, based on ASTM D150, with a dielectric constant of 1 measured at 1 kHz at room temperature. Examples of the resin having a relative dielectric constant of 5 or less include polystyrene, silicon resin, ABS resin, etc., but polyethylene, polypropylene, polyfluorinated ethylene, etc. having a relative dielectric constant of 3 or less are preferable. A resin having a melting point of more than 100 ° C. such as ethylene fluoride is preferable.

  The container may be formed of a solid film or plate-like sheet, may be formed of a film or plate-like sheet made of a foam, or a combination thereof. For example, in the case of a bag, both sides may be formed of a solid film or plate sheet, or a foam film or plate sheet, or one side is a solid film or plate sheet, and the opposite side. May be formed of a foam film or a plate-like sheet. In addition, these both surfaces may be structured such that a cooling medium directly contacts the outer wall formed of a single film or plate-like sheet, and a liquid chamber such as glycerin or a buffer layer such as sponge is formed between them. May be. It is preferable to use a closed-cell foam as the foam used in the container, because evaporation of water contained in the cold medium can be prevented.

The cold insulation material formed as described above is used as a cold insulation material in a state of being cooled or frozen in a refrigeration or freezer, or immersed in hot water, or in some cases microwaved in a microwave oven to store heat in a cold medium. It is used as a heat insulating material in the finished state. In use, when used as a cold insulator, the cooling medium absorbs external heat through the container and cools it. When used as a heat insulating material, the heat stored in the cold medium is transferred to the outside through the container and heated. When the cooling medium absorbs heat or dissipates heat and the cooling or heating capacity is reduced, the cold insulation material is cooled or heated again and used.

  Thus, unlike the conventional product, the water phase and the thickener phase are separated in the use of the cold insulation heat material, and the cold insulation heat effect is lowered in the conventional product. Then, water does not separate from the cross-linked gelatin, maintains a stable gel state for a long period of time, and can be used repeatedly for a long period of time. This is the same even when a large amount of water is included exceeding the water content in the conventional product. Even when the moisture is frozen and used as a cold insulation material, ice crystals do not separate and grow due to freezing, and even if they are melted, phase separation does not occur, and the cold insulation heat effect is maintained.

  The phase separation of gelatin cross-linked gel does not occur even when used repeatedly in this way due to the extreme strength of affinity between cross-linked gelatin and water, and a phenomenon that cannot be predicted from conventional polyacrylic acid cross-linked products. It is. Collagen is very biased in amino acid composition. About 35% by weight of glycine, about 11% by weight of alanine, about 21% by weight of proline and hydroxyproline, 2/3 of amino acids are hydrophilic, and collagen itself is highly hydrophilic. . Gelatin in which this is modified has a higher hydrophilicity due to cleavage of covalent bonds or formation of hydroxyl groups. Such a cross-linked gelatin obtained by cross-linking gelatin also has a network structure in a state where the properties thereof are maintained, so that it has excellent water retention and water is difficult to separate from the network structure of the cross-linked gelatin.

  The high hydrophilicity of such cross-linked gelatin is due to the high hydrophilicity of specific gelatin and is greatly different from other proteins. For example, the above-mentioned frozen tofu is formed from soy protein, but water is easily separated by freezing and thawing in the same manner as agar mainly composed of alginic acid. In contrast, cross-linked gelatin is much more hydrophilic, and water does not separate from the cross-linked gelatin even after repeated cooling and heating cycles. For this reason, it is useful as a cooling medium for the cold insulation material.

  Since gelatin is highly hydrophilic, gelatin itself can be used as a cooling medium. However, by cross-linking this gelatin, it has a network structure, so that the water retention is further enhanced and the shape maintaining property is also enhanced. In particular, when used as a granulated or pulverized product, the adhesion between the granulated or pulverized products is lost, and independent granulated or pulverized products are used as the cooling medium. In this case, a layer of air is formed between the granulated or pulverized products, so that the entire heat does not flow intensively and is transferred from the granulated or pulverized products to other granulated or pulverized products. Heat transfer or heat dissipation is prevented, and heat storage and cold insulation efficiency are increased.

  Granulated or pulverized cross-linked gelatin is used as a cooling medium, filled in a soft container such as a resin bag, and used as a cold insulation material. The whole filling shape can be freely changed without being bonded to each other, and can be fitted to the shape of the heat transfer surface of the heat-receiving part, so that the heat transfer effect can be enhanced. In particular, when the cooling medium is used in a frozen state, if the whole is a single gel layer, the whole becomes a hardened layer as a single frozen layer, and it may not be possible to fit the shape of the heat transfer surface of the cooled part. However, by using a granulated or pulverized product of cross-linked gelatin, the contact surface between the granulated or pulverized products can be shifted and the overall filling shape can be changed, thereby changing the shape of the heat transfer surface of the cooled portion. In addition to being able to be fitted, an air layer is interposed between the granulated or pulverized products, so that rapid cooling is alleviated, heat storage properties are increased, and sustainability and heat insulation efficiency are increased. The same effect can be obtained when a foam is used for the container.

When using a cold insulation material that contains a cooling medium in a container, if the container is made of a heat-resistant and microwave-permeable material, the microwave will pass through the container even if it is heated in a microwave. Is not heated, and water contained in the cold medium is heated and stored in resonance with the microwave. For this reason, a container does not deteriorate by heating. Gelatin is also heated by microwaves because it has polarity, but because of the presence of water, the superheating temperature is kept below the boiling point of water and the crosslinked gelatin does not deteriorate. In addition, even if the resin is microwave permeable, it may deteriorate in the case of a resin with a low softening point such as polyethylene, but it is a heat resistant resin having a melting point of more than 100 ° C. such as polypropylene and polyfluorinated ethylene. If there is little deterioration, it can be used repeatedly over a long period of time.

  Since the cooling medium of the present invention includes gelatin crosslinked gel containing crosslinked gelatin and water, the amount of water contained in the cooling medium can be increased, thereby reducing the cost, increasing the heat capacity and extending the heat retention time. Thus, the heat retention effect can be increased, and even when the cooling or heating cycle is repeated, water is not separated, and the repeated use time can be extended.

  The cooling medium containing the granulated or pulverized product of the cross-linked gelatin and water-containing gelatin cross-linked gel of the present invention loses the adhesion between the granulated or pulverized products, and independent granulated or pulverized products are used as the cooling medium. Since there is a layer of air between the granulated or pulverized product, the entire heat does not flow intensively and is transferred from the granulated or pulverized product to the granulated or pulverized product. Heat dissipation is prevented, and heat storage and cooling heat efficiency are increased.

  In the cold insulation material of the present invention, since the cooling medium containing the gelatin crosslinked gel containing crosslinked gelatin and water is contained in the container, the amount of water contained in the cooling medium can be increased, thereby reducing the cost and increasing the heat capacity. In addition, the heat retention time can be lengthened to increase the heat retention heat effect, and even when the cooling or heating cycle is repeated, water is not separated, and the repeated use time can be lengthened.

  The cold insulation heat material in which the cold medium containing the granulated or pulverized product of the gelatin crosslinked gel containing the crosslinked gelatin and water of the present invention is housed in a soft container is crunchy without any adhesion between the granulated or pulverized products. The shape of the filler can be freely changed, and it can be fitted to the shape of the heat transfer surface of the cooled part, the heat transfer effect can be increased, and an air layer is interposed between the granulated or pulverized products Rapid cooling is relieved, heat storage is increased, and sustainability and heat insulation efficiency are increased.

  The cold insulation material in which the cooling medium of the present invention is housed in a heat-resistant and microwave permeable container is not heated even if microwave heating is performed in a microwave oven, and the water contained in the cooling medium is converted into microwaves. Since the container is heated and stored in resonance, the container is not deteriorated by heating and can be used repeatedly over a long period of time.

(A) is a top view of the cold insulation heat material of one Embodiment, (b) is the AA sectional drawing. (A) is a top view of the cold insulation heat material of other embodiment, (b) is the BB sectional drawing.

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment of FIG. 1, the cold insulation heat material 1 is formed in a pack shape in which a cold heat medium 2 including a gelatin crosslinked gel containing crosslinked gelatin and water is accommodated in a container 3. The whole of the cooling medium 2 may be one lump, but is preferably filled with granulated or pulverized material. The container 3 is composed of a container body 4 having an adhesive portion 4a in the periphery and a lid portion 5 having an adhesive portion 5a in the periphery. The container 3 has a tube shape in which the container body 4 and the lid portion 5 are integrated. You may comprise. Although the container 3 may be a hard container, it is preferable to use a soft container because it can be fitted to the shape of the heat transfer surface of the cooled portion.

  The cold insulation heat material 1 accommodates the cooling medium 2 containing gelatin cross-linked gelatin and water-containing gelatin cross-linked gel between the container body 4 and the lid 5, and the adhesive portion 4 a and the adhesive portion 5 a are bonded by an adhesive or heat seal. It is manufactured by bonding and forming in a pack shape. When the cooling medium 2 is a single block, the aqueous sol containing gelatin as a raw material for the gelatin cross-linking gel, a cross-linking agent and other components added as necessary is allowed to react in a state of being contained in the container 3. Thus, the cooling medium 2 is formed. When the cooling medium 2 includes granulated or pulverized material, the container 3 is filled with the granulated or pulverized material obtained by granulating or pulverizing the preformed cooling medium 2, and the bonding portion 4a and the bonding portion 5a are formed. Manufactured by bonding.

  The cold insulation heat material 1 manufactured as described above is used as a cold insulation material in a state of being cooled or frozen in a refrigeration or freezer, or immersed in hot water, or in some cases, microwave heated in a microwave oven, 2 is used as a heat insulating material in a state where heat is stored. When the cold insulation material 1 is used as a cold insulation material, the cold medium 2 absorbs external heat through the container 3 and cools it. When the cold insulation material 1 is used as a heat insulation material, the heat stored in the cold medium 2 is transmitted to the outside through the container 3 and heated. When the cooling medium 2 absorbs heat or dissipates heat and the cooling or heating ability is reduced, the cold insulation heat material 1 is cooled or heated again and used.

  In the case where the cold insulation heat material 1 in which a soft gelatin container 3 such as a resin bag is filled with granulated or pulverized cross-linked gelatin as the cooling medium 2 is used, there is no adhesion between the granulated or pulverized products. The entire filling shape can be freely changed without being bonded to each other or the pulverized product can be fitted to the shape of the heat transfer surface of the cooled portion, and the heat transfer effect can be enhanced. In particular, when the cooling medium 2 is used in a frozen state, if the whole is a single gel layer, the whole becomes a hardened layer as a single frozen layer, and cannot be fitted to the shape of the heat transfer surface of the cooled portion. In some cases, by using a granulated or pulverized product of cross-linked gelatin, the entire filling shape of the cooling medium 2 can be changed by shifting the contact surface between the granulated or pulverized products. Can be fitted to the shape of the heat transfer surface of the part, and by interposing an air layer between the granulated or pulverized products, rapid cooling is mitigated, heat storage is enhanced, and sustainability and heat insulation efficiency are improved. Get higher. The same effect can be obtained when the container 3 is made of foam.

  When the container 3 of the heat insulating material 1 is made of a heat-resistant and microwave-permeable material, even if microwave heating is performed in a microwave oven, the microwave is transmitted through the container 3, so the container 3 is not heated and the cooling medium The water contained in 2 is heated and stored in resonance with the microwave. For this reason, the container 3 made of a microwave permeable material is not deteriorated by heating, and particularly when it is made of a foam made of a microwave permeable material, heating by the microwave is reduced. In particular, the container 3 made of a heat-resistant resin having a melting point of more than 100 ° C. such as polypropylene and polyfluorinated ethylene is less likely to be deteriorated by heat and can be used repeatedly over a long period of time.

  In the embodiment of FIG. 2, in the cold insulation heat material 1, the divided cooling medium 2 containing gelatin crosslinked gel containing crosslinked gelatin and water is accommodated in a number of accommodating portions 4 b formed in the container body 4 of the container 3. It is covered with a lid 5 from above and formed into a pack shape. Adhesive portions 4a are formed between and around the multiple accommodating portions 4b of the container body 4, and portions facing the lid portions 5 are bonded to each other as adhesive portions 5a. The adhesive portions 4a and 5a are further extended to form a belt-like portion 6.

The cold insulation heat material 1 is made of a material of the container 3, in particular, the bonding portions 4a and 5a made of a soft material, thereby facilitating bending at the bonding portions 4a and 5a, and having a wide heat transfer portion. Even in the case of a hot surface, it can be easily fitted and the heat transfer effect can be enhanced. Further, in this state, it can be tied and fixed by the belt-like portion 6, and usability can be improved. The cooling medium 2 accommodated in the container 3 and other configurations and functions are the same as those in FIG.

  Hereinafter, the present invention will be described with reference to examples and comparative examples. In each example,% is% by weight.

[Examples 1 to 5, Comparative Example 1]:
Gelatin having a molecular weight of 50,000 to 100,000, a ring-opening isobutene-maleic anhydride copolymer as a crosslinking agent to form a sodium hydroxide salt (number average molecular weight 8,000), an antibacterial agent, ethanol as an organic solvent, And water were added in the proportions shown in Table 1, and the mixture was reacted at room temperature for 24 hours to be gelatinized. A gelatin crosslinked gel containing crosslinked gelatin and water was produced, and the jelly strength of the gel after 24 hours was measured. Further, the gelatin cross-linked gel was pulverized by a pulverizer with a rotary blade to obtain a pulverized product having a particle diameter of 3 to 4 mm. The blending ratio (%) and the results are shown in Table 1. In Table 1, the properties of the pulverized product were determined as follows.
A: There is a sticky feeling between the particles B: There is a wet feeling between the particles C: There is fluidity between the particles (paraple feeling)
D: Good fluidity between particles E: High fluidity between particles

  100 g of the pulverized product of Example 2 was put in a polyethylene bag, stored in a freezer at −5 ° C. for 24 hours, then taken out, attached with a thermocouple on the surface of the bag, and allowed to stand at room temperature (25 ° C.) every 10 minutes. The temperature was measured. As Comparative Example 1, a commercial product using CMC as a thickener was similarly tested. The results are shown in Table 2. From Table 2, it can be seen that Example 2 is not too cold in Comparative Example 1, and the temperature rise is moderate, it can be cooled for a long time, and heat storage is high.

[Examples 6-8, Comparative Examples 2-7]:
Examples 6 to 8 include gelatin having a molecular weight of 50,000 to 100,000, a ring-opened isobutene-maleic anhydride copolymer as a crosslinking agent to form a sodium hydroxide salt (number average molecular weight 8,000), antibacterial An agent, ethanol as an organic solvent, and water were added in the proportions shown in Table 1, and the mixture was reacted at room temperature for 24 hours to be gelatinized to produce a gelatin-crosslinked gel containing crosslinked gelatin and water, and the jelly strength of the gel after 24 hours Was measured. Further, the gelatin cross-linked gel was pulverized by a pulverizer with a rotary blade to obtain a pulverized product having a particle diameter of 3 to 4 mm. Table 3 shows the compounding ratio (%) and the jelly strength. Table 4 shows the blending ratio (%) of Comparative Examples 2 to 7.

[Cold insulation test]:
100 g of the pulverized products of Examples 6 to 8 and Comparative Examples 2 to 7 were put in a polyethylene bag, stored in a freezer at −5 ° C. for 24 hours, then taken out, covered with a towel, and a thermocouple on the lower surface of the bag. Was attached and allowed to stand at room temperature (25 ° C.), and the temperature was measured. This cooling test was repeated 10 cycles, and the presence or absence of water separation was determined. The results are shown in Tables 5 and 6.

  In Examples 6 to 8 shown in Table 5, there was no water separation even when the 10-cycle cooling test was repeated, and an excellent cooling effect was shown. On the other hand, in Comparative Examples 2 to 7 shown in Table 6, water separation occurred and a cold insulation test could not be performed. First, in Comparative Example 2, water separation occurred from the first cycle, the surface was frozen until 50 minutes passed, and the center was frozen after that, and the cold insulation test could not be performed. In Comparative Example 3, a large amount of water separation occurred from the first cycle, and a frozen part was present throughout until 180 minutes, and a cold insulation test could not be performed. In Comparative Example 4, water separation was low in the first cycle, but water separation occurred after the second cycle, and the cold insulation test could not be performed. In Comparative Example 5, a large amount of water separation occurred from the first cycle, and a frozen portion was present on the surface until the lapse of 180 minutes, and a cold insulation test could not be performed. In Comparative Example 6, water separation was small in the first to third cycles, but water separation occurred after the fourth cycle, and the cold insulation test could not be performed. In Comparative Example 7, water separation occurred from the first cycle, and a frozen portion was present throughout until 30 minutes, and thereafter, the central portion was in a frozen state, and a cold insulation test could not be performed.

[Insulation test]:
100 g of the pulverized products of Examples 6 to 8 and Comparative Examples 2 to 7 were put in a polypropylene bag, microwaved for 1.5 minutes in a microwave oven, then taken out and covered with a towel, and placed on the lower surface of the bag. Attach a thermocouple, leave it at room temperature (25 ° C), measure the temperature, drop temperature difference (° C) dropped by 180 minutes, and drop time required to drop from 55 ° C to 35 ° C ( Minute). The results are shown in Tables 7 and 8. From Tables 7 and 8, Examples 6 to 8 in Table 7 have a smaller temperature drop compared to Comparative Examples 2 to 7 in Table 8, and the time required for the temperature to drop from 55 ° C to 35 ° C. It can be seen that the heat retention effect is high.

[Examples 9 to 12]:
Examples 9 to 12 include gelatin having a molecular weight of 50,000 to 100,000, a ring-opened isobutene-maleic anhydride copolymer as a crosslinking agent to form a sodium hydroxide salt (number average molecular weight 8,000), antibacterial An agent, ethanol as an organic solvent, and water were added in the proportions shown in Table 1, and the mixture was reacted at room temperature for 24 hours to be gelatinized to produce a gelatin-crosslinked gel containing crosslinked gelatin and water, and the jelly strength of the gel after 24 hours Was measured. Further, the gelatin cross-linked gel was pulverized by a pulverizer with a rotary blade to obtain a pulverized product having a particle diameter of 3 to 4 mm. Table 9 shows the blending ratio (%) and the jelly strength.

[Insulation test]:
100 g of the pulverized product of Examples 9 to 12 was put in a polypropylene bag, microwaved for 1.5 minutes in a microwave oven, then taken out and covered with a towel, a thermocouple was attached to the lower surface of the bag, The temperature was measured by standing at (25 ° C.), and the descent time (minutes) required to drop the temperature from 55 ° C. to 35 ° C. was measured. The results are shown in Table 10. From Table 10, it can be seen that in Examples 9 to 12, the temperature drop is small, the time required for temperature drop from 55 ° C. to 35 ° C. is long, and the heat retention effect is high.

  It is a gelatin cross-linked gel-based cold medium, and can be used as a cold-heat medium used for cooling or heating, particularly by storing heat, and a gelatin-cross-linked gel-based cold heat retaining material for keeping cold or keeping warm with this cold medium.

DESCRIPTION OF SYMBOLS 1 Cold insulation heat material 2 Cooling medium 3 Container 4 Container main body 4a, 5a Adhesion part 4b Storage part 5 Cover part 6 Strip | belt-shaped part

Claims (9)

  A cold medium comprising a gelatin crosslinked gel comprising crosslinked gelatin and water.   A cold medium containing a granulated or pulverized product of gelatin crosslinked gel containing crosslinked gelatin and water.   The cooling medium according to claim 1 or 2, wherein the gelatin crosslinked gel contains 2 to 60% by weight of crosslinked gelatin and 40 to 98% by weight of water, and has a jelly strength of 9 to 3000g.   4. The reaction product of an aqueous sol according to claim 1, wherein the gelatin cross-linked gel comprises 2 to 59% by weight of gelatin, 1 to 20% by weight of a cross-linking agent, and 40 to 97% by weight of water, A cold medium that is 3000 g.   The cold medium according to claim 4, wherein the gelatin has a molecular weight of 10,000 to 500,000.   The cooling medium according to claim 4 or 5, wherein the crosslinking agent is an ethylenically unsaturated compound-maleic anhydride copolymer, a ring-opened product thereof or a salt thereof.   A cold insulation heat material in which a cold heat medium containing a gelatin crosslinked gel containing the crosslinked gelatin and water according to any one of claims 1 to 6 is contained in a container.   A cold insulation heat material in which a cold medium containing a granulated or pulverized product of a gelatin crosslinked gel containing the crosslinked gelatin and water according to any one of claims 2 to 6 is contained in a soft container.   The cold insulation heat material according to claim 7 or 8, wherein the container is a heat-resistant and microwave-permeable container.

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