Composition and heat storage material including composition

Abstract

To provide a novel composition for heat storage materials having superior performance, and also to provide a heat storage material including the composition for heat storage materials.SOLUTION: One embodiment of the present invention is a composition for heat storage materials, the composition comprising water, a formate, and trimethylolethane.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition and a heat storage material comprising the composition.

Background Art

[0002] One of the heat storage materials for maintaining a predetermined temperature is a phase change material. The phase change material refers to a material having a function of keeping the temperature constant by utilizing the latent heat during the phase change from the solid phase to the liquid phase.

[0003] One of the characteristics required for the heat storage material is a function of keeping warm in a relatively high temperature range (for example, 0 °C or higher), particularly in food applications and pharmaceutical applications. Conventionally, many of the technologies used for heat preservation in such a high temperature range were heat storage materials using paraffin, but since paraffin is a combustible substance, there was a problem in safety.

[0004] There have been attempts to improve safety by using a heat storage material using a hydrate having heat preservation properties at 0 °C or higher. For example, Patent Document 1 discloses a latent heat storage material having a melting point in the range of 9 to 10 °C, which is a combination of sodium sulfate decahydrate and ammonium chloride or ammonium bromide.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Thus, although there has conventionally been a latent heat storage material using a hydrate having a melting point in a region of a relatively high temperature, such a latent heat storage material has problems such as insufficient heat preservation properties.

[0007] Therefore, an object of the present invention is to provide a novel composition for a heat storage material having excellent heat retention properties in a region where the temperature is relatively high, and a heat storage material including the composition for the heat storage material.

Means for Solving the Problems

[0008] The present inventor has conducted intensive studies and found that the above problems can be solved by a composition containing specific components. That is, the present invention is as follows.

[0009] One aspect of the present invention is a composition. The composition includes water, a formate, and trimethylolethane. The composition is for a heat storage material.

[0010] The composition preferably has a melting point of less than 14.0°C.

[0011] The ratio of the content of trimethylolethane to the content of the formate (trimethylolethane / formate) is preferably 2.0 or less, and the ratio of the content of trimethylolethane to the content of water (trimethylolethane / water) is preferably 1.5 or less.

[0012] Another aspect of the present invention is a heat storage material including a container and the composition stored in the container.

Effects of the Invention

[0013] According to the present invention, it is possible to provide a novel composition for a heat storage material having excellent performance, and a heat storage material including the composition for the heat storage material.

Modes for Carrying Out the Invention

[0014] In the following, when an upper limit value and a lower limit value are separately described, a numerical range obtained by combining any upper limit value and any lower limit value is considered to be substantially disclosed.

[0015] In the following, when a certain compound is described, its isomers shall also be considered as being described simultaneously.

[0016] In the following, unless otherwise specified, all kinds of measurements are carried out with the environmental temperature being room temperature (25°C).

[0017] Hereinafter, the components, physical properties / characteristics, uses, etc. of the composition will be specifically described, but the present invention is not limited thereto.

[0018] <<Component>> The composition of the present disclosure preferably contains water, a formate, and trimethylolethane. The composition of the present disclosure may contain other components. Hereinafter, each component will be described.

[0019] <Water> As the water, pure water or ultrapure water such as distilled water, ion-exchanged water, RO (reverse osmosis membrane) water, etc. may be used.

[0020] The content of water in the composition can be adjusted in consideration of the concentration of other components, etc. The content of water is preferably, for example, 15.0% by mass or more, 20.0% by mass or more, 30.0% by mass or more, 36.0% by mass or more, or 40.0% by mass or more when the total amount of the composition is 100.0% by mass from the viewpoint of heat storage property, etc. In a composition containing a formate and trimethylolethane, it is easy to obtain a uniform composition by relatively increasing the content of water (for example, setting it to 36.0% by mass or more). Also, the content of water is preferably 80.0% by mass or less, 60.0% by mass or less, 50.0% by mass or less, 48.0% by mass or less, or 44.0% by mass or less. By setting the content of water within such a range, the latent heat amount of the composition can be increased.

[0021] <Formate> The formate is preferably an alkali metal salt and / or an alkaline earth metal salt, more preferably an alkali metal salt (e.g., lithium salt, sodium salt or potassium salt), still more preferably a sodium salt or a potassium salt, and particularly preferably a sodium salt.

[0022] By including the formate in the composition, it is easy to obtain a composition that is excellent in terms of the latent heat amount and the like and is preferable as a heat storage material. In particular, by using sodium formate as the formate, it becomes easier to obtain a composition having a melting point near 12°C while maintaining the latent heat.

[0023] When the total amount of the composition is 100.0% by mass, the content of the formate (e.g., sodium formate) is preferably 5.0% by mass or more, 8.0% by mass or more, 10.0% by mass or more, 15.0% by mass or more, or 20.0% by mass or more, and is preferably 60.0% by mass or less, 50.0% by mass or less, 40.0% by mass or less, 35.0% by mass or less, less than 32.5% by mass, or 32.0% by mass or less. By setting the content of the formate (e.g., sodium formate) within such a range, it is easy to obtain a composition excellent in latent heat amount.

[0024] <Trimethylolethane> By using a composition in which the formate and trimethylolethane are combined, it is easy to obtain a composition that is excellent in terms of the latent heat amount and the like and is suitable for heat insulation in a region where the temperature is relatively high (e.g., a temperature range of 0.0°C or more and less than 14.0°C, or 10.0°C or more and less than 14.0°C).

[0025] When the total amount of the composition is 100.0% by mass, the content of trimethylolethane is preferably 5.0% by mass or more, 8.0% by mass or more, 10.0% by mass or more, 15.0% by mass or more, 20.0% by mass or more, 25.0% by mass or more, or 28.0% by mass or more, and is preferably 60.0% by mass or less, 50.0% by mass or less, or 40.0% by mass or less. By setting the content of trimethylolethane within such a range, it is easy to obtain a composition excellent in latent heat amount.

[0026] In the composition, the ratio of the content of trimethylolethane to the content of formate (trimethylolethane / formate) is preferably 3.0 or less, 2.5 or less, or 2.0 or less. The lower limit value of this content ratio is, for example, 0.2, 0.5, or 0.8. By setting the content ratio within such a range, it is easy to obtain a composition that is uniform and excellent in latent heat quantity.

[0027] In the composition, the ratio of the content of trimethylolethane to the content of water (trimethylolethane / water) is preferably 3.0 or less, 2.5 or less, 2.0 or less, 1.5 or less, or 1.2 or less. The lower limit value of this content ratio is, for example, 0.2, 0.4, 0.5, or 0.6. By setting the content ratio within such a range, it is easy to obtain a composition that is uniform and excellent in latent heat quantity.

[0028] More preferably, in the composition, the ratio of the content of trimethylolethane to the content of formate (trimethylolethane / formate) is 2.0 or less, and the ratio of the content of trimethylolethane to the content of water (trimethylolethane / water) is 1.5 or less.

[0029] <Other components> The composition may contain known components such as an anti-phase separation agent (including a thickening agent (gelling agent)), a coloring agent (dye, pigment), an antibacterial agent, a viscosity modifier, an anti-supercooling agent (for example, those that can serve as crystal nucleating agents such as ice nucleating bacteria, calcium carbonate, sodium sulfate, disodium hydrogen phosphate, borax, activated carbon, silver iodide, mineral-based, etc.), an antifoaming agent, and an organic solvent other than water.

[0030] Examples of the phase separation inhibitor include sodium silicate, water glass, polyacrylic acid, sodium polyacrylate, polycarboxylate polyether polymer, polycarboxylic acid polymer, polyglycerin, polyglycerin ester, polyglycerin ether, sodium acrylate / maleic acid copolymer, sodium acrylate / sulfonic acid-based monomer copolymer, acrylamide / dimethylaminoethyl methacrylate dimethyl sulfate copolymer, sodium acrylamide / sodium acrylate copolymer, polyethylene glycol, polypropylene glycol, superabsorbent resin (SAP), carboxymethyl cellulose (CMC), derivatives of CMC, carrageenan, derivatives of carrageenan, xanthan gum, derivatives of xanthan gum, pectin, derivatives of pectin, starch, derivatives of starch, konjac, agar, layered silicate, and the like.

[0031] The content of the phase separation inhibitor in the composition can be adjusted so that the composition has predetermined physical properties and is not particularly limited. For example, when the total amount of water, formate, and trimethylolethane is 100.0 parts by mass, the content of the phase separation inhibitor in the composition is preferably 0.1 part by mass or more, 0.5 part by mass or more, or 1.0 part by mass or more, and is preferably 10.0 parts by mass or less, or 5.0 parts by mass or less.

[0032] <<Physical properties / Properties>> <Thermal properties> The composition of the present disclosure can have a melting point of less than 14.0°C. More specifically, according to the composition of the present disclosure, it can have a melting point in a region of a relatively high temperature such as 0.0°C or more and less than 14.0°C, 5.0°C or more and less than 14.0°C, 8.0°C or more and less than 14.0°C, 10.0°C or more and less than 14.0°C, or 12.0°C or more and less than 14.0°C. Therefore, it is useful as a novel composition for a heat storage material.

[0033] The melting behavior of the composition can take the form of having a single melting peak, a form having a plurality of melting peaks (two melting peaks), or a form having a broad melting peak in a DSC chart (a chart with differential scanning calorimetry on the vertical axis and temperature on the horizontal axis) obtained by differential scanning calorimetry (DSC) described later. Among these, the composition preferably has a form with a single peak in the DSC chart. The form with a single peak means that [Condition 1] it does not have a plurality of melting peaks, and [Condition 2] in the DSC chart, when the half-width at half-maximum of the melting peak height is A (°C) and the absolute value of the difference between the melting end temperature and the melting start temperature is B (°C), B / A is 3.0 or less (preferably 2.5 or less, or 2.0 or less).

[0034] The peak state can be adjusted by changing the water content, formate content, and trimethylolethane content in the composition. In other words, based on the ternary diagram of the water content, formate content, and trimethylolethane content in the composition, the peak state can be estimated.

[0035] The latent heat of the composition of the present disclosure can be 80 J / g or more, 100 J / g or more, 115 J / g or more, 120 J / g or more, or 150 J / g or more.

[0036] The melting point and latent heat of the composition are obtained by differential scanning calorimetry (DSC). Specifically, it is as follows. About 10 mg of the composition is put into an aluminum pan for DSC measurement, heated to 25 °C, then cooled to -35 °C at a rate of 1 °C / min to solidify, and then heated to 25 °C at a rate of 1 °C / min. The melting point and latent heat are obtained from the peak apex and area that appear during the phase change. When the composition has a plurality of peaks (melting peaks), the temperature corresponding to the lowest peak position is taken as the melting point of the composition.

[0037] <Viscosity> The viscosity of the composition can be appropriately changed according to the use and is not particularly limited. When the composition contains a gel component, the viscosity of the composition can be 1.0 Pa·s or more, 2.0 Pa·s or more, 5.0 Pa·s or more, 10 Pa·s or more, 100 Pa·s or more, or 500 Pa·s or more. The upper limit value of the viscosity of the composition is not particularly limited, but is, for example, 2000 Pa·s or less.

[0038] Note that the viscosity of the composition is the viscosity at 25°C measured using a B-type rotational viscometer.

[0039] <<Use>> The composition according to the present disclosure is preferably used as a heat storage material, a food and beverage heat insulation utensil, or a medical product heat insulation utensil. In other words, a preferred form of the composition according to the present disclosure is a composition for a heat storage material, a food and beverage heat insulation utensil, or a medical product heat insulation utensil. Further, the composition according to the present disclosure can also be preferably used as a material constituting a contact cold feeling member or the like.

[0040] Hereinafter, as an example of a specific usage method of the composition according to the present disclosure, a heat storage material including the composition according to the present disclosure, and preferred examples of a food and beverage heat insulation utensil and a medical product heat insulation utensil including the composition according to the present disclosure will be described.

[0041] <Heat storage material> The heat storage material includes a container and a composition housed in the container.

[0042] Since the composition has been described above, a detailed description thereof will be omitted. As described above, the composition may be gelled (including a gel component). By using the gelled composition, leakage of the liquid material when the container is damaged can be suppressed.

[0043] The material of the container may have flexibility that can be deformed according to the phase change (solidification and melting) of the composition.

[0044] The heat storage material may be of a so-called soft type in which the container is constituted by a member that is easily deformable, such as a resin film or a metal film, or may be of a so-called hard type in which the container is constituted by a member that is difficult to deform, such as a thick resin material (for example, a hollow molded body).

[0045] The heat storage material only needs to have at least the composition sealed therein, and may be configured such that the composition can be taken out or injected without destroying the container, such as having an openable lid, etc., or may be configured such that it is difficult to take out the composition except by destroying the container.

[0046] The size and shape of the heat storage material can be appropriately changed according to the use of the heat storage material.

[0047] The heat storage material may include components other than the container and the composition.

[0048] <Food and beverage heat preservation utensils and medical product heat preservation utensils> Food and beverage heat preservation utensils, and medical product heat preservation utensils include, for example, a container and the composition according to the present disclosure stored in the container.

[0049] Since the composition has been described above, a detailed description thereof will be omitted.

[0050] The container is, for example, a box-shaped article and has a space inside the container capable of accommodating an object to be heat-preserved, such as food. A composition storage portion in which the composition according to the present disclosure is stored is arranged on one or more or all of the inner side surface, the inner bottom surface, and the inner top surface of the container. The composition storage portion may be configured to be removable from the container or may be integrated with the container. The container usually has an opening / closing portion, and when the opening / closing portion is operated, it becomes a sealed state or an open state. The container is preferably constituted by a member having heat insulation properties. By accommodating an object to be heat-preserved, such as food or a medical product, in the space inside the container in a state where the composition is solidified, the object to be heat-preserved can be heat-preserved.

[0051] Examples of objects to be kept warm by food and beverage warmers include fresh produce such as cold vegetables and fruits, processed foods such as ham, and beverages (water, tea-based beverages, coffee-based beverages, fruit beverages, vegetable beverages, sports beverages, etc.).

[0052] Examples of objects to be kept warm by medical product warmers include medical products that include some pharmaceuticals that require low-temperature storage (for example, vaccines, blood products, red blood cell products, cells, etc.).

Example

[0053] Hereinafter, the composition (composition for heat storage material) will be specifically described by way of examples, but the present invention is not limited thereto.

[0054] <<Preparation of Composition>> By blending the raw materials in the blending amounts (parts by mass) shown in Tables 1 and 2 and stirring, the compositions according to Examples 1 to 23 and Comparative Examples 1 to 4 were obtained. For Example 23, after blending each component, heating and cooling at 50 °C were performed to enhance the uniformity of the composition.

[0055] <<Evaluation>> <Melting Point and Heat of Fusion>[ Based on the differential scanning calorimetry described above, the melting point and heat of fusion of each composition were measured. The measurement results of each item are shown in Tables 1 and 2.

[0056] In addition, based on the differential scanning calorimetry described above, the peak state of each composition was evaluated. Those having a single melting peak were designated as "1", those having a plurality of melting peaks (two melting peaks) were designated as "1d", and those having a broad melting peak were designated as "1B". The evaluation results are shown in each table.

[0057]

Table 1

[0058]

Table 2

[0059] As described above, the composition according to the present embodiment has a melting point in a region that is a relatively high temperature of 0.0°C or higher and less than 14.0°C, and also has a sufficiently high latent heat, and thus is useful as a heat storage material. Further, the composition according to the present embodiment is advantageous in terms of high safety and the like. Also, Examples 1-22 are considered to be advantageous in that a uniform composition is more likely to be formed as compared with Example 23 (it is possible to reduce the energy during production (less environmental load)). Also, as a result of appropriately adjusting the blending ratio of each component and the like in Examples 4-12 and 14-22, the latent heat is 115.0 J / g or more, and it has excellent performance as a heat storage material.

Industrial Applicability

[0060] Since the composition of the present invention is excellent in performance such as heat retention in a region of relatively high temperature, it can be preferably applied as a heat storage material.

Claims

1. A composition comprising water, formate, and trimethylolethane, characterized by being used as a heat storage material.

2. The composition according to claim 1, having a melting point of less than 14.0 °C.

3. The composition according to claim 1, wherein the ratio of the content of trimethylolethane to the content of formate (trimethylolethane / formate) is 2.0 or less, and the ratio of the content of trimethylolethane to the content of water (trimethylolethane / water) is 1.5 or less.

4. A heat storage material comprising a container and the composition according to any one of claims 1 to 3 stored in the container.

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