Temperature control agent, heat generating composition and heating body containing the same

Abstract

The present invention provides a means for realizing temperature control of a heating element (particularly control of the maximum heat generation temperature) at lower cost and more simply, which can be used in place of or in conjunction with conventional temperature control by controlling the supply of oxygen or air using a breathable film or the like, and which prevents or reduces the decrease in heat generation temperature due to deterioration of the heating element over time and the effects of storage at high temperatures (temperature deterioration of a heat generation composition during long-term storage), and a heating element using the same. [Solution] A temperature control agent containing an aliphatic compound is used to control the heat generation temperature of a heating element (2) containing a heat-generating composition (1) that generates heat upon reaction with oxygen, wherein the aliphatic compound has a melting point of 35°C or higher, a water solubility at 20°C of 5g / 100mL or less, and is in a particulate form with an average circularity of 0.70 to 1.0.

Description

[Technical Field]

[0001] The present invention relates to a temperature control agent used in the manufacture of heating elements such as chemical hand warmers (hand warmers) that generate heat by reacting with oxygen, hot compress structures, and heating devices for stimulating meridians, a heat-generating composition containing the same, and a heating element using the same. [Background technology]

[0002] Heating bodies using heat-generating compositions that generate heat upon contact with oxygen or air are widely used as medical devices such as hot compresses and meridian-stimulating heating devices for alleviating pain through heat, or as everyday items such as body warmers and other heating devices for protection against the cold.

[0003] The heat-generating compositions used in such heaters most commonly contain metal powders such as iron powder, salts such as table salt, water, and moisture-retaining agents such as activated carbon as constituents, and generate heat by the heat of oxidation produced when the metal reacts with oxygen. Therefore, the heat-generating properties have traditionally been adjusted to fall within a desired range depending on the purpose of the heater by controlling the amount of oxygen inflow through the breathable packaging material, particularly the breathable (porous) film, of the bag that contains the heat-generating composition.

[0004] These methods can be used to adjust the maximum temperature, rise time, duration, etc. of heat generation, and the product is designed to optimize these when used under certain conditions. However, strict control of packaging performance imposes a burden on manufacturing costs. Furthermore, no matter how high-performance breathable packaging materials are used, if the amount of ventilation in actual use is not as designed due to the manner of use or pinholes in the bag, the intended performance may not be achieved or safety issues may arise.

[0005] Similar problems exist with medical heating elements, which require more accurate temperature control. For example, transdermal medical hot compresses, which combine a heating element with a drug, are touted for their benefits, such as increased effectiveness and reduced drug dosage due to the more efficient transdermal absorption caused by heat. However, as mentioned above, conventional temperature control methods do not provide complete stability in the generated temperature, which in turn results in unstable drug dosages.

[0006] In response to these problems, the inventors discovered that by incorporating a component containing a specific aliphatic compound as a temperature control agent into the heat-generating composition or the packaging material of the bag or container that contains it, it is possible to improve the temperature stability of the heating element in a way other than by regulating the amount of oxygen inflow (Patent Document 3).

[0007] Although thermal materials are composed of relatively stable components and can be stored at room temperature for a certain period of time while being protected from oxygen, temperature changes during storage, particularly exposure to high-temperature environments, can reduce shelf life and the maximum temperature. Thermal materials containing temperature control agents may also fail to reach the intended heat generation temperature after opening if stored for a long period of time. However, the inventors have discovered that this problem can be overcome by setting the particle size of the temperature control agent within a specified range (Patent Document 4).

[0008] However, it has been found that the phenomenon of reduced shelf life in such high-temperature environments has a significant impact, particularly when the amount of exothermic composition contained in the heating element is small, and that even when the intended heating temperature is reached, the temperature tends to drop rapidly thereafter. Furthermore, conventional temperature control agents are prone to deterioration unless they have a relatively large particle size, but large particles are difficult to mix uniformly with other particulate components in the exothermic composition, which can result in variations in the temperature characteristics of the heating element. Therefore, further improvements in such temperature control agents are desirable in terms of safety, temperature stability, long-term storage properties, and the like. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication WO1999 / 000078 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-170099 [Patent Document 3] International Publication WO2016 / 063815 [Patent Document 4] International Publication WO2019 / 151472 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to provide a means for achieving temperature control of a heating element (particularly control of the maximum heat generation temperature) at lower cost and with less effort, which can be used in place of or in combination with conventional temperature control methods that use breathable films to control the amount of oxygen or air supplied, and which prevents or reduces the decrease in the heating temperature of a heating element due to aging and storage at high temperatures (temperature deterioration of the exothermic composition during long-term storage), and a heating element using such a means. Another objective of the present invention is to provide a more advanced temperature control means that can be used for heating elements for medical use, and to provide an improved heating element for medical use that is safer and more effective. Another objective of the present invention is to facilitate uniform distribution of temperature control agent particles in the exothermic composition, reduce variation in the temperature characteristics of the heating element, enable the above-mentioned more advanced temperature control, and extend the duration of the heating element's optimal temperature during use. In particular, the present invention aims to provide a temperature control agent that can be uniformly mixed into the exothermic composition, even when used in small heating elements with small amounts of exothermic composition, and can extend the duration of heat generation in small heating elements. [Means for solving the problem]

[0011] According to the present invention, [1] A temperature control agent containing an aliphatic compound, which is used to control the temperature of a heating element containing a heat-generating composition that generates heat upon reaction with oxygen, wherein the aliphatic compound has a melting point of 35°C or higher, a water solubility at 20°C of 5g / 100mL or less, and is in a particulate form with an average circularity of 0.70 to 1.0; [2] The temperature control agent according to [1] above, wherein the aliphatic compound is in a particulate form that does not pass through a 325 mesh standard sieve (standard size according to JIS Z8801-1: 44 μm); [3] The temperature control agent according to claim 1 or 2, wherein the aliphatic compound is in a particulate form that passes through a 16-mesh standard sieve (standard size according to JIS Z8801-1: 1000 μm). [4] The temperature control agent according to any one of [1] to [3] above, wherein the aliphatic compound contains one or more compounds selected from the group consisting of higher α-olefin copolymers, paraffin wax, myristyl myristate, polyester polyols, and polyoxyethylene fatty acid diesters; [5] A heat-generating composition that generates heat upon reaction with oxygen, the heat-generating composition comprising a metal powder, a salt, water, activated carbon, and a temperature control agent for controlling the heat generation temperature of the heat-generating composition, wherein the temperature control agent is the temperature control agent according to any one of [1] to [4] above; [6] A heating element comprising the heat-generating composition according to [5] above and a bag or container containing the heat-generating composition, at least a portion of which is breathable; [7] The thermal body according to [6], wherein the bag or container is housed in an airtight outer bag that substantially blocks oxygen; [8] The heating element according to [6] or [7], which is used as either a disposable body warmer or a medical device; [9] The thermal body according to [8], wherein the medical device is either a hot compress or a thermal device for stimulating meridians;

[10] A method for producing a temperature control agent according to any one of [1] to [4], comprising a step of forming a molten material obtained by melting the aliphatic compound or the temperature control agent into spherical particles by an atomization method. is provided. [Effects of the Invention]

[0012] According to the present invention, a simple, low-cost, and reliable temperature control means is provided for a heating element that can be used in place of or in addition to temperature control using a breathable film, and the maximum heat generation temperature remains stable even after long-term storage, resulting in a heating element with superior temperature stability and high safety. According to the present invention, the uniformity of the distribution of temperature control agent particles in the heat-generating composition is improved, reducing variation in the temperature characteristics of the heating element. Furthermore, according to the present invention, a heating element with a longer heat generation duration than conventional heating elements can be provided, even when using the same amount of heat-generating composition. Furthermore, according to the present invention, the range of particle sizes generated during the process of spherically granulating the temperature control agent raw material can be narrowed, and when classifying large or small particles, the high fluidity of the resulting particles improves work efficiency and reduces raw material loss, providing manufacturing advantages.

[0013] Surprisingly, it was found that a heating element using a heat-generating composition containing the temperature control agent of the present invention has excellent quality stability when stored at high temperatures, and also has a low rate of temperature decrease after heat generation is stopped, allowing for a safe and long-lasting warmth.

[0014] In particular, the present invention provides a heating element that is suitable for long-term emergency storage, for example, and that has a low risk of low-temperature burns even when used while sleeping. - A heating element that can be safely used while sleeping, reducing the risk of low-temperature burns caused by covering the mattress; - Highly safe disposable warmers for shoes that provide stable heat regardless of the type of shoes and do not cause a sudden rise in temperature even when taking off the shoes; - Transdermal medical hot compress with high temperature stability, safety and effectiveness; - A heating device for stimulating meridians such as moxibustion, which can be used safely by controlling the maximum temperature even in high temperature zones etc. will be provided. [Brief explanation of the drawings]

[0015] [Figure 1] Figure 1 shows examples of samples obtained by classifying the same aliphatic compound that has been mechanically pulverized and that has been atomized into spherical particles. The left image is a digital microscope photograph, and the right image is a processed image for measuring the average circularity (both at 200x magnification). [Figure 2] Figure 2 shows the results of a time degradation test in which heating elements (Examples 1 to 7) containing an α-olefin copolymer (melting point 58°C) spherically atomized by atomization as a temperature control agent were stored at 50°C. For each panel, "initial" represents the heat generation pattern immediately after production; "2W" represents the heat generation pattern after two weeks of storage; "1M" represents the heat generation pattern after one month of storage; and "2M" represents the heat generation pattern after two months of storage. [Figure 3] Figure 3 shows the results of a time degradation test in which heating elements (Comparative Examples 1 to 7) containing mechanically pulverized α-olefin copolymers (melting point 58°C) as a temperature control agent were stored at 50°C. For each panel, "initial" represents the heat generation pattern immediately after production, "2W" represents the heat generation pattern after two weeks of storage, and "1M" represents the heat generation pattern after one month of storage. [Figure 4] Figure 4 shows an example of the structure of a small heating element that can be used as a meridian-stimulating heating device (moxibustion device) of the present invention. Panel A is a cross-sectional view of the moxibustion device, Panel B is a perspective view of a heat-generating composition tablet (1), Panel C is a perspective view of the heat-generating composition tablet (1) placed in a container body (2), and Panel D is a perspective view of the container body (2) containing the heat-generating composition tablet (1) together with an adhesive-treated top material (adhesive tape) (3) attached thereto. Note that the heat-generating composition tablet (1) in Figure 4 is shown schematically in its form before water (or salt water) is added (before swelling). [Figure 5]FIG. 5 shows a comparison of the heat generation behavior when excessive heat generation is induced between a heating element (Example 8) using a heat generation composition containing an α-olefin copolymer (melting point 58°C) spherically granulated by atomization as a temperature control agent, and a heating element (Comparative Example 8) using a heat generation composition containing an α-olefin copolymer (melting point 58°C) pulverized by mechanical pulverization. [Figure 6] FIG. 6 shows a comparison of the heat generation behavior when excessive heat generation is induced between a heating element (Example 9) using a heat generation composition containing an α-olefin copolymer (melting point 58°C) spherically granulated by atomization as a temperature control agent, and a heating element (Comparative Example 9) using a heat generation composition containing an α-olefin copolymer (melting point 58°C) pulverized by mechanical pulverization. [Figure 7] FIG. 7 shows a comparison of the heat generation behavior when excessive heat generation is induced between a heating element (Example 10) using a heat generation composition containing an α-olefin copolymer (melting point 58°C) spherically granulated by atomization as a temperature control agent, and a heating element (Comparative Example 10) using a heat generation composition containing an α-olefin copolymer (melting point 58°C) pulverized by mechanical pulverization. DETAILED DESCRIPTION OF THE INVENTION

[0016] Temperature Control Agent The temperature control agent of the present invention is characterized by containing one or more aliphatic compounds having a melting point of 35°C or higher and a water solubility of 5 g / 100 mL or less at 20°C. The solubility is preferably 3 g / 100 mL or less, more preferably 1 g / 100 mL or less. The preferred melting point of the aliphatic compound varies depending on the application of the heating element and can be selected appropriately. However, to prevent deterioration of heat generation characteristics during storage, the preferred melting point is generally 35°C or higher, preferably 38°C or higher. The upper limit is generally 70°C or lower, preferably 65°C or lower, to ensure the safety of the heating element. In this specification, the term "aliphatic compound" refers to an organic compound in which all carbon atoms in the molecule are connected in a single chain, or a compound that has a branched carbon atom chain but does not contain a cyclic structure. This term includes anhydrides of chain dicarboxylic acids, imides, lactones of hydroxy acids, cyclic ethers, and other compounds that have a cyclic structure containing oxygen or nitrogen, but are closely related to the parent chain compound and easily open the ring to form a chain compound.

[0017] Aliphatic compounds having such properties can be selected from higher α-olefin copolymers, various paraffin waxes such as vegetable, animal, or petroleum-based, myristyl myristate, polyester polyols, polyoxyethylene fatty acid diesters, etc. In this specification, higher α-olefin copolymer refers to a copolymer of two or more α-olefins having 10 to 35 carbon atoms, or one or more α-olefins having 10 to 35 carbon atoms with one or more other olefins. In other words, higher α-olefin copolymers are copolymers of two or more α-olefins having 10 to 35 carbon atoms, or copolymers of one or more α-olefins having 10 to 35 carbon atoms with one or more other olefins.

[0018] The higher α-olefin copolymer used in the present invention may be a main-chain crystalline polyolefin, in which the main chain is folded and crystallizes, but a side-chain crystalline polyolefin having a certain long-chain α-olefin in the side chain is preferred. Side-chain crystalline polyolefins have sharp melting behavior and are conveniently non-sticky when not molten. Such side-chain crystalline polyolefins are commercially available, for example, under the trade name "HS Crysta" (Toyokuni Seiyu). Similarly, paraffin wax (e.g., Nippon Seiro), myristyl myristate (e.g., Croda Japan), polyester polyols (e.g., DIC, Toyokuni Seiyu), polyoxyethylene fatty acid diesters (e.g., Sanyo Chemical), and higher α-olefin copolymers are also commercially available.

[0019] Melting point measurements are performed using a differential scanning calorimeter as follows: 5 mg to 15 mg of sample is placed in an aluminum (Al) container, and an Al crimp cover is placed over it, sealing it with a certain amount of pressure. Using the Al container and crimp cover as a reference, the temperature is raised at a rate of 5°C / min from the estimated melting point of -50°C to +30°C. After holding for 5 minutes, the sample is cooled at the same rate and held at the estimated melting point of -50°C for 5 minutes. This process is repeated twice, and the DSC curve for the second cycle (2nd run) is measured. The melting point is read from the main endothermic peak that appears on the DSC curve due to the endothermic heat associated with melting the sample.

[0020] Water solubility at 20°C can be measured by dissolving a sample in 100 g (100 mL) of water at 20°C and reading the mass of the sample at the limit at which it no longer dissolves (the maximum amount dissolved).

[0021] The aliphatic compound contained in the temperature control agent of the present invention can be used by processing raw materials in the form of pellets, powder, blocks, etc. at room temperature into spherical particles. Any known method applicable to resins may be used to produce spherical particles. Examples of methods that can relatively easily produce large amounts of spherical particles include powder melting and atomization. By selecting appropriate conditions in these methods, the size of the resulting spherical particles can be controlled within a desired range.

[0022] In the powder melting method, powdered raw materials are introduced into, for example, a flame or thermal plasma, a vertical tubular furnace, or a tower kiln, where they are melted at a temperature above their melting point and then sphericalized by the surface tension of the molten material itself. Alternatively, a dispersion of the raw materials in a solvent or the like may be sprayed from a nozzle or the like into the flame, thermal plasma, or vertical tubular furnace, where the dispersion medium is evaporated to form spherical particles.

[0023] The atomization method is a method in which raw materials in the form of powder or bulk are melted in a heat-resistant container, and the molten material is dropped or sprayed through a nozzle or the like, and rapidly cooled and solidified to form spheroids. Any melting method can be used as long as it is possible to heat the raw materials to their melting point or higher. The raw materials are preferably melted in an atmosphere such as air, an inert gas, or a vacuum.

[0024] As the atomization method, various known methods can be appropriately used, for example, any of gas atomization, centrifugal atomization, hybrid atomization, water atomization, etc. can be suitably used.

[0025] For example, in gas atomization, the melting temperature is preferably 50 to 200°C, more preferably 70 to 150°C. The opening diameter of the nozzle for spraying the molten material is preferably 0.2 to 3.0 mm, more preferably 0.5 to 2.0 mm. Examples of gases include air and argon gas. The fluid spray pressure is preferably 0.3 to 5 MPa, more preferably 0.5 to 3 MPa. In centrifugal atomization, the melting temperature is preferably 50 to 200°C, more preferably 70 to 150°C. The diameter of the nozzle at the bottom of the crucible can be appropriately selected depending on the physical properties of the material to be powdered, the target particle size, the production rate, the scale of the equipment, etc. The material for the disk can also be appropriately selected as long as it has a melting point higher than the melting temperature and is resistant to thermal shock.

[0026] The aliphatic compound contained in the temperature control agent of the present invention is in the form of particles having an average circularity of 0.70 to 1.0. The average circularity is preferably 0.75 or more, 0.76 or more, 0.77 or more, or 0.78 or more, and more preferably 0.79 or more. The methods for measuring and calculating the circularity of individual particles and the average circularity of a particle group will be described in detail in the Examples.

[0027] In this specification, the particle size of an aliphatic compound is indicated by classification using a standard sieve (Tyler sieve). The size of the sieve openings is generally indicated by "mesh" or "μm" (the standard size (μm) of the openings of a metal sieve in JIS Z8801-1 (2006), also referred to as the nominal size), and the correspondence between them is well known. Conventional temperature control agents have been considered desirable to contain a particulate form that does not pass through a 60-mesh standard sieve (opening 250 μm) and also passes through a 16-mesh standard sieve (opening 1000 μm). However, according to the present invention, there is no limitation on particle size, and even those containing small particle-sized aliphatic compounds that have traditionally been excluded can be suitably used as temperature control agents. Therefore, commercially available aliphatic compounds can be appropriately selected and spherically granulated and then used as they are for the temperature control agent of the present invention.

[0028] Furthermore, the temperature control agent of the present invention can be prepared by forming the aliphatic compound raw material into spherical particles, and then sieving (classifying) the particles into those that pass through various standard sieves and those that do not, as necessary, and then blending them appropriately to achieve the desired heat generation pattern. When particularly precise temperature control is required, it is desirable to control the particle size within a predetermined range. The aliphatic compound contained in the temperature control agent of the present invention is preferably in a particulate form that does not pass through a 325-mesh standard sieve (opening 44 μm). In some cases, it is preferable that the particulate form does not pass through a 250-mesh standard sieve (opening 63 μm). Furthermore, to further improve uniform dispersion in the heat-generating composition, it is preferable that the particulate form pass through a 16-mesh standard sieve (opening 1000 μm), and even more preferably a 32-mesh standard sieve (opening 500 μm).

[0029] The aliphatic compound particle population may be of completely uniform particle size, and there are no particular restrictions on the particle size distribution of the particles in the population. However, it is desirable that the particles passing through a 325 mesh standard sieve (openings 44 μm) account for less than 50%, and more desirably less than 30%, of the entire temperature control agent, taken as 100%.

[0030] In this specification, "not passing through" a sieve with a certain mesh size means that 60% or more of the total material does not pass through the sieve, preferably 80% or more, and more preferably 90% or more. Most preferably 100%. Similarly, "passing through" a sieve with a certain mesh size means that 60% or more of the total material passes through the sieve, preferably 80% or more, and more preferably 90% or more. Most preferably 100%.

[0031] The mechanism by which the use of the temperature control agent of the present invention stabilizes heat generation characteristics is believed to be as follows, although not limited to a specific theory. When a temperature control agent is added to a heat-generating composition, the temperature control agent melts when the heat generation temperature reaches near the melting point of the temperature control agent, coating the iron powder and inhibiting oxidation reactions, thereby suppressing temperature rise. The aliphatic compound components in the temperature control agent may contain not only those with a single measured melting point, but also those with a melting point lower than this (low-melting-point resins). One possibility is that in temperature control agents obtained by conventional mechanical pulverization methods, such low-melting-point resins melt quickly and inhibit heat generation, thereby contributing to a decrease in heat generation temperature after high-temperature storage. On the other hand, in the case of the temperature control agent of the present invention, which contains aliphatic compounds formed into spherical particles by atomization or other methods, the low-melting-point resin hardens first to form a nucleus, and then the remaining resin components harden around this nucleus, thereby reducing the influence of the low-melting-point resin and thereby suppressing a decrease in heat generation temperature.

[0032] Therefore, it has been thought that using particles that do not pass through a 60-mesh standard sieve (openings 250 μm) would be less susceptible to temporary changes in environmental temperature during storage than using finer particles, making the temperature control agent less likely to melt accidentally (and reduce the maximum heat generation temperature), but the temperature control agent of the present invention is less susceptible to the effects of particle size and is thought to exhibit good performance even with smaller particle sizes. Furthermore, conventional particles are prone to uneven dispersion in the exothermic composition, which is thought to cause variations in the time it takes to reach the maximum temperature, but the temperature control agent of the present invention can use smaller particle sizes, making it easier to disperse uniformly in the exothermic composition, and is thought to reduce variations in the temperature characteristics of the exothermic composition or heating element.

[0033] The maximum temperature and heat generation pattern to be achieved vary depending on the application of the heating element, so the type and content of the temperature control agent are selected to achieve the required heat generation performance.

[0034] For example, a hot compress hand warmer that is applied directly to the skin should preferably generate heat at around 40°C, but if it exceeds 43°C, protein denaturation occurs, increasing the risk of low-temperature burns. Therefore, it is desirable to design it so that the temperature does not exceed 43°C, and if there is a possibility that the temperature may rise above 43°C, it is desirable to quickly suppress the temperature rise to the appropriate level of around 40°C. On the other hand, it is undesirable for the temperature to continue to drop after suppression, as this reduces the thermal effect. Furthermore, even for hot compress hand warmers that are applied directly to the skin, a mild heat generation of below 40°C is preferable when they are applied to the delicate abdomen of women to relieve menstrual pain.

[0035] On the other hand, disposable heating pads that are attached to clothing are generally used at a maximum temperature of around 55°C because the skin is protected by clothing. Small heating elements used to heat a limited area, such as moxibustion tools, are used at relatively high temperatures for a short period of time, but because they come into direct contact with the skin without being covered by clothing, it is desirable for them to be designed to not exceed around 55°C. Furthermore, for small heating elements used as moxibustion tools, it is desirable for the temperature to drop quickly after suppressing the temperature rise. In contrast, for similar small heating elements intended to provide mild thermal stimulation, it is desirable for the appropriate temperature to be maintained for a certain period of time, given the constraint of a small amount of exothermic composition.

[0036] Thus, since there are maximum temperatures and heat generation patterns suitable for each of the various types of thermal bodies, one or more aliphatic compounds having a melting point close to the desired maximum temperature (for example, a melting point that is about -20°C to +10°C of the maximum temperature (i.e., the maximum temperature is within about +20°C to -10°C of the melting point), preferably a melting point that is within ±8°C of the maximum temperature, and more preferably a melting point that is within ±5°C of the maximum temperature) can be appropriately selected as the temperature control agent, and the amount to be added, the addition method, the addition of optional ingredients, etc. can be designed. For example, to control the maximum temperature to about 55°C, an aliphatic compound with a melting point of 58°C can be selected.

[0037] Heat-generating composition The exothermic composition of the present invention contains at least a metal powder, a salt, water, and activated carbon, and further contains the temperature control agent of the present invention. The temperature control agent is as described above.

[0038] As the metal powder, iron powder is generally used, but other materials that generate heat of oxidation may also be used. As the salt, inorganic salts such as sodium chloride, potassium chloride, and magnesium chloride are generally used. The exothermic composition of the present invention contains activated carbon, but may also contain a water-retaining agent other than activated carbon (e.g., water-absorbent polymer, vermiculite, sawdust, silica-based material, etc.). Furthermore, various other conventionally known components may be added as needed.

[0039] An example of the blending ratio of these components is, based on 100% by weight of the heat-generating composition, 35-80% by weight of iron, 1-20% by weight of activated carbon, 1-10% by weight of salts, 5-45% by weight of water, and 0-45% by weight of a water-retaining agent other than activated carbon. The heat-generating composition of the present invention preferably contains 30-70% by weight of iron, 1-15% by weight of activated carbon, 1-5% by weight of salts, 20-30% by weight of water, and 1-25% by weight of a water-retaining agent other than activated carbon. The amount of the temperature-regulating agent can be appropriately selected depending on the intended use of the heating element and the maximum temperature to be achieved, as described above. For example, 3-40 parts by weight, preferably 3-30 parts by weight, of the temperature-regulating agent of the present invention is added to 100 parts by weight of the heat-generating composition and mixed.

[0040] The exothermic composition can be produced by mixing the essential ingredients described above and optional ingredients selected as necessary, using known methods, under low-oxygen or oxygen-free conditions when salt and water are added in advance. The exothermic composition may be in the form of a powder, which may be further processed by known methods, for example, into cubes by tableting or sheets by rolling. When the exothermic composition is formed into a solid form, a binder such as cellulose (e.g., crystalline cellulose), lactose, starch, dextrin, sucrose ester, Teflon (registered trademark), polyethylene glycol, or carboxymethyl cellulose may be added. For example, to form a solid tablet by tableting, a binder such as crystalline cellulose may be added in an amount of 5 to 30 parts by weight, preferably 10 to 30 parts by weight, per 100 parts by weight of the exothermic composition to produce a tablet of the desired appropriate hardness. Such solid exothermic compositions are preferred because they prevent sealing defects due to powder adhesion to the sealed portion of a bag or container during packaging and eliminate variations in exothermic temperature. Regarding the exothermic composition, salts may be mixed at the same time as the powdered raw materials are mixed, or may be added as salt water.

[0041] The exothermic composition of the present invention containing such a temperature control agent can be tested according to JIS S4100 exothermic test by measuring the temperature change over time when reacted with oxygen in the air through a breathable packaging material (for example, a porous film of 17,000 to 18,000 seconds / 100 cc or a nonwoven fabric of 0 seconds / 100 cc (both according to JIS P8117 method (Oken test method)) used in the exothermic composition storage bag or container to house the composition, to confirm whether the desired maximum temperature has been achieved. Note that the exothermic test conducted for this purpose may be conducted by appropriately modifying the experimental conditions so as to reflect the expected actual usage conditions.

[0042] packaging material The exothermic composition is filled into a bag or container for containing the exothermic composition. The bag or container filled with the exothermic composition can be used as a heating body (for example, a non-stick type body warmer) as is. Generally, the bag or container for containing the exothermic composition is formed so that at least a portion thereof is breathable.

[0043] The breathable packaging material that constitutes the bag or container for containing the heat-generating composition changes the heat-generating characteristics of the heating element (such as the rate at which heat is generated, the duration of heat generation, and heat transfer to the object to be heated, such as the human body or clothing), so any known material can be appropriately selected and used so that these characteristics fall within the desired range depending on the intended use.

[0044] Common human body warmers and the like use breathable packaging materials with an air permeability of 10,000 to 40,000 seconds / 100cc (JIS P8117 (Oken test method)). Shoe warmers, for example, use 2,000 to 7,000 seconds / 100cc. Therefore, as breathable packaging materials for bags or containers containing exothermic compositions, packaging materials with an air permeability of 2,000 to 40,000 seconds / 100cc are generally used. For warmers designed for high temperature and / or short-term use, such as meridian-stimulating heating devices, packaging materials with an air permeability of 0 to 10,000 seconds / 100cc can be used. By using the temperature control agent of the present invention, precise air permeability control is not required depending on the application of the warmer, broadening the acceptable range of breathable packaging materials that can be used.

[0045] In the present invention, the breathable packaging material used for the bag or container may be a film or sheet that is breathable entirely or partially. Generally, breathable packaging materials include single-layer or laminated porous films or sheets used alone or in combination with woven or nonwoven fabrics, or single-layer or laminated imperforate films or sheets with pinholes, used alone or in combination with woven or nonwoven fabrics. In the present invention, the term "film" primarily refers to a single material (including single-layer and laminated materials; the same applies hereinafter) or a relatively thin material, and the term "sheet" primarily refers to a single material, a laminate of two or more single materials, or a relatively thick material, although no strict distinction is made between the two.

[0046] The resin constituting the film is generally a thermoplastic synthetic resin. Specifically, polyethylene, polypropylene, polyester, polyamide, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyurethane, polystyrene, ethylene-vinyl acetate copolymer, polycarbonate, etc. are preferably used alone or in combination. They can be appropriately selected depending on the purpose, the required heat generation amount, temperature, the heat-generating composition to be used, etc.

[0047] In the present invention, a stretched film, preferably a stretched porous film or a sheet containing the same, is suitably used as the breathable film or sheet. Stretched porous films generally contain an inorganic filler, and exhibit breathability by forming continuous pores through stretching. The breathability can be controlled by controlling the pore size, etc.

[0048] Lamination is usually performed by lamination, but is not limited to this. Any conventionally known method can be used for lamination. For example, lamination may be performed by thermal bonding or with an adhesive such as a hot melt adhesive or an acrylic or urethane adhesive. Full-surface bonding or partial bonding to maintain flexibility may also be used. Preferably, a curtain spray method or a dry lamination method is used.

[0049] Nonwoven fabrics are generally used in breathable packaging materials from the viewpoint of reinforcing the strength of the packaging material and improving its mechanical properties. Nonwoven fabrics that may be laminated with the above-mentioned film are preferably those conventionally used in the technical fields of heating bodies and medical heating devices. Examples include those containing artificial fibers such as nylon, vinylon, polyester, rayon, acetate, acrylic, polyethylene, polypropylene, and polyvinyl chloride, and natural fibers such as cotton, hemp, and silk, and include nonwoven fabrics in the form of spunbond, thermalbond, and spunlace. The basis weight of nonwoven fabrics varies depending on the specific gravity of the nonwoven material and the bulkiness due to differences in the entanglement method, but is generally about 10 g / m 2 ~about 200g / m2 A thickness of about 20 g / m is particularly suitable. 2 ~about 100g / m 2 is preferred.

[0050] In particular, breathable sheets in which a stretched porous film of a thermoplastic synthetic resin is laminated with a nonwoven fabric of nylon, polyester fiber, or the like are commonly used.

[0051] A part of the bag or container, for example, the backside packaging material of a flat bag, may be either an air-permeable packaging material as described above or an air-impermeable packaging material. The air-impermeable packaging material may be a single-layer or laminated film or sheet of the resin as described above, and there are no particular limitations on the material, thickness, configuration, etc., as long as it is suitable for forming a bag or container for containing an exothermic composition.

[0052] A bag or container for containing an exothermic composition can be produced by using the above-mentioned packaging material and gluing the periphery by a method commonly used in this technical field. A heating element can basically be produced by sealing the exothermic composition of the present invention into this bag or container. Generally, the production of the bag or container and the production of the heating element are continuous, with the periphery of the overlapping packaging material first heat-sealed or glued together with an adhesive, leaving a small portion uncovered, the exothermic composition is poured through the opening, and then this opening is glued together and the exothermic composition is sealed inside.

[0053] Furthermore, for example, small-sized exothermic bodies with a small application area and / or a short usage time, such as moxibustion tools, the exothermic composition may be produced by storing it in a container with a thickness of, for example, several mm to several cm, rather than in a flat bag. In this case, the lid (top material) and the container body (cup) can be produced using packaging materials made of various materials as described above. For example, the top material (Fig. 4) can contain layers such as a sealant material (3a), a nonwoven fabric (3b), an adhesive (3c), and a release paper (3d) as needed. A specific example is a layer made of, in order from 3a, LLDPE (30 μm) / PET spunlace nonwoven fabric (30 g / m 2) / SIS-based hot melt adhesive / PET separator (38 μm). As mentioned above, in the case of moxibustion tools and other devices that utilize high temperature and / or short-term heat generation, packaging materials with very high breathability can be used, so nonwoven fabric may be used alone for the top material and / or the container body. In this specification, a "small" heating element refers to a heating element that is smaller than a standard, so-called mini-sized disposable hand warmer, and more specifically, refers to one with a diameter or length of one side of 5 cm or less, or even 3 cm or less.

[0054] Heat source The thermal element can be a bag filled with the exothermic composition of the present invention (e.g., a disposable warmer that does not stick) or a container (e.g., a moxibustion tool), as described above. However, additional elements can be added as needed. These various elements are known and may be integrated into the bag or provided as separate components to be combined at the time of use. Examples of additional elements include various fastening means and various parts to be combined at the time of use (e.g., a container containing fragrances or medicines, a sheet containing water or cosmetics, or other components used depending on the intended use of the thermal element). Examples of fastening means include an adhesive layer or poultice layer formed on the surface of a portion of the bag or container containing the exothermic composition to allow the thermal element to be applied; a band-like member to be wrapped around the target to secure it; a mask, supporter, or wristband with a pocket to accommodate the thermal element. Furthermore, for purposes such as temperature regulation, a base may be provided between the container and the adhesive layer to adjust the distance and / or space between the application site and the thermal element. The heating element of the present invention may contain various drugs or fragrances, such as camphor or menthol, in the adhesive layer, the compress layer, or other components, or in the exothermic composition and / or packaging material or container. For example, hot receptors such as capsicum tincture, capsicum extract, capsicum powder, ginger tincture, ginger extract, ginger powder, fennel tincture, fennel extract, fennel powder, capsaicin, capsaicin derivatives, vanillyl butyl ether, vanillyl alkyl ether, and nonylic acid vanillylamide may be added to the adhesive. Cold receptors such as l-menthol, peppermint, dl-camphor, peppermint oil, thymol, and oxalic acid menthyl ethylamide may be added to the adhesive.

[0055] The bag or container of the heating element containing at least the exothermic composition is sealed in an outer bag that blocks oxygen and is stored until use. Such outer bags are also known. For long-term storage, outer bags that have low oxygen permeability to minimize oxidation of iron during storage and that include an aluminum layer with low water vapor permeability to minimize the release of water vapor from the outer bag are particularly preferred. [Example]

[0056] <Production of temperature control agent> Alpha-olefin copolymer (Toyokuni Oil Mills, "HS Crysta-6100") (lump or powder, melting point 58°C) was melted at 110°C using an applicator (PHAL BOK SYSTEM CO., LTD., "Nino-30"), and the melt was then pumped at a speed of 55 Hz (flow rate of approximately 1.7 kg / min) through a mist nozzle (Ikeuchi Co., Ltd., "Standard Fan Nozzle, Model 1 / 4M-VVP-5010-S303") and sprayed into the inlet of a rotating drum that was cooled while rotating. After the melt cooled in the rotating drum and turned into spherical powder in mid-air, the powder was collected from the outlet opposite the inlet (sometimes referred to as "atomized product"). For comparison, the same α-olefin copolymer was mechanically pulverized using a vertical cutting mill (Orient Mill) and / or a quick mill, and powder was collected (sometimes referred to as "mechanically pulverized product").

[0057] The atomized and mechanically crushed products were each sieved stepwise using JIS-standard stainless steel sieves (Tokyo Screen Co., Ltd., frame diameter 200 x 60 mm, specification JIS Z8801-1:2000) with mesh sizes of 500 μm, 250 μm, 150 μm, 105 μm, 63 μm, or 44 μm. The fraction that did not pass through the 500 μm sieve and the fraction that passed through the 44 μm sieve were removed, and the following fractions were collected: 500-250 μm, 250-150 μm, 150-105 μm, 105-63 μm, and 63-44 μm. The atomized product contained almost no fraction that did not pass through the 500 μm sieve.

[0058] Using each fraction, the following seven temperature control agent samples were prepared and used to produce exothermic compositions. (1) 250 to 150 μm (2) 150 to 105 μm (3) 105 μm to 63 μm (4) 63 μm to 44 μm (5) 250 to 44 μm (a mixture of equal weights of (1) to (4) above) (6) 150 to 44 μm (a mixture of equal weights of (2) to (4) above) (7) 105 to 44 μm (a mixture of equal weights of (3) and (4) above) Representative digital microscope photographs and images (described later) of the produced temperature control agent samples (samples (4) and (3) above) are shown in FIG.

[0059] <Measurement of circularity> The average circularity was calculated for each of the samples obtained above. Each temperature control agent sample granulated as described above was spread out so that the particles did not overlap as much as possible, and photographed using a digital microscope (Keyence Corporation, main body "VHX-500F", lens "VH-Z100R") and recorded as an image. The particles were binarized using image processing software (ImageJ), and the area and perimeter of the particle projection diagram for each particle were measured. In this case, particles with an area less than half the diameter of the sieve lower limit were excluded from the evaluation (for example, when the lower limit is a mesh size of 44 μm, a diameter of 22 μm (i.e., an area of ​​379 μm) was excluded). 2 )The following were excluded: The circularity was calculated by the following formula: Circularity = 4π x area / (perimeter) 2 ...(Formula 1) The average value of the circularity of 80 to 100 particles calculated in this manner was taken as the average circularity of particles for each sample of Examples 1 to 4 and Comparative Examples 1 to 4.

[0060] The average circularity calculated for each sample is shown in Table 1. For Examples 5 to 7 and Comparative Examples 5 to 7, which were prepared by blending Examples 1 to 4 and Comparative Examples 1 to 4 at a weight ratio, the average circularity of the blended samples was calculated by weighting the average circularity of the blended samples in consideration of the number of particles contained ((C) in Table 1), and this was used as the average circularity of the sample.

[0061] [Table 1]

[0062] <Production of Heat-Generating Composition (1)> The raw materials for the heat-generating composition were iron powder (Powder Tech Co., Ltd., reduced iron powder "RDH-3M"), activated carbon (Dainen Co., Ltd., activated carbon (wet carbon) "PL-1P (30% wet)", water-absorbent polymer (Sanyo Chemical Co., Ltd., polyacrylate resin "ST-500D*"), crystalline cellulose (Asahi Kasei Chemicals Co., Ltd., crystalline cellulose "TG-101"), sodium chloride (Nihon Kaisui Co., Ltd. Powdered salt "EF-300" and one of the temperature control agents prepared above were mixed with 45 parts of iron powder, 8.4 parts of activated carbon (wet), 5 parts of water-absorbent polymer, 30 parts of crystalline cellulose, 3.5 parts of sodium chloride, and 25 parts of temperature control agent (all "parts" are by weight) to produce a heat-generating composition. Specifically, taking into consideration bulk density and particle size, the following ingredients were weighed and added to a beaker in this order: crystalline cellulose, aliphatic compound (temperature control agent), water-absorbent polymer, activated carbon, sodium chloride, and iron powder. The mixture was thoroughly stirred with a medicine spoon to eliminate uneven distribution of each ingredient. The composition of each heat-generating composition sample is shown in Table 2.

[0063] [Table 2]

[0064] <Manufacturing small heating elements> Similar to the example shown in FIG. 4, a small-sized heating element consisting of a container body (2) containing a heat-generating composition tablet (1) and a top material (3) was produced as follows.

[0065] 1.2 g of the heat-generating composition produced above was weighed out and compressed into tablets (compression pressure 10 kN) using a Fuji Yakuhin Kikai "Desktop Prototype Tablet Press Quick Mini FY-TQM-30" (tabletting pressure 10 kN). A male die (punch) with a diameter of 13.9 mm and a receiving die (mortar) with an inner diameter of 14 mm was used to produce cylindrical tablets with a diameter of 14 mm and a thickness of 5 mm.

[0066] A container for containing the exothermic composition tablets was manufactured as follows. First, a truncated conical male mold with a bottom diameter of 20 mm, a top diameter of 15 mm, and a height of 8 mm was prepared, and a cylindrical receiving female mold with a diameter of 21 mm and a height of 25 mm was prepared. The male mold was heated to 105°C. A moldable nonwoven fabric (Asahi Kasei Corporation, thermoformable PET spunbond nonwoven fabric "Smash Y15250" (basis weight 250 g / m²)) was placed on the female mold. 2 )") was pressed into the heated male mold, held for 3 seconds, then cooled by applying room temperature compressed air for another 3 seconds, and the male mold was immediately removed from the female mold to produce a cup-shaped molded product.

[0067] A tablet was placed in a molded nonwoven fabric cup, and the top material (PET separator (38 μm) / rubber-based hot melt adhesive (100 g / m)) was attached to the top of the container (the bottom side of the truncated cone) using a cylindrical welding mold heated to 160°C. 2 ) / PET spunlace nonwoven fabric (weight 50g / m 2 ) / PET film (12 μm) / PE film (30 μm)) was attached. Furthermore, 0.39 g of a 2% aqueous solution of sodium sulfite was injected into the top material using a syringe. The container was sealed in an airtight outer bag (PET (12 μm) / aluminum foil (7 μm) / LLDPE (50 μm) (Toho Kako Co., Ltd.)) to prepare the heating elements of Examples 1 to 7 and Comparative Examples 1 to 7, respectively.

[0068] <Melt point and solubility measurements> The melting points of aliphatic compounds were measured using a differential scanning calorimeter (DSC6220, manufactured by Seiko Instruments Inc.) connected to a fully automatic cooling unit and an analysis system (EXSTAR6000 thermal analysis rheology system, using DSC Muse measurement software and DSC Muse standard analysis software). The sample containers used were an open-type aluminum sample container, φ5.2 H2.5 (50 μL), and an open-type aluminum sample container (crimp cover).

[0069] 5 mg to 15 mg of sample was placed in an Al container, and an Al crimp cover was placed over it and sealed under a certain pressure. Using the Al container and crimp cover as a reference, the temperature was raised at a rate of 5°C / min from the estimated melting point of -50°C to +30°C. After holding for 5 minutes, the sample was cooled at the same rate and held at the estimated melting point of -50°C for 5 minutes. This cycle was repeated twice, and the DSC curve for the second run was measured. The melting point was determined as described above from the endothermic peak that appeared on the DSC curve due to the endothermic heat generated by the sample melting.

[0070] The powder of the aliphatic compound was dissolved in 100 g (100 mL) of water at 20° C., and the mass of the limiting amount at which the compound no longer dissolved was read, thereby measuring the solubility in water.

[0071] The melting point of the α-olefin copolymer used was 58° C. The solubility was less than 1 g / 100 mL.

[0072] <Aging test (storage test)> The storage test was conducted at 50°C and 35% relative humidity in an Advantech Toyo Co., Ltd. low-temperature, constant temperature and humidity chamber, model THE051FA. Two weeks of storage at 50°C is equivalent to one year of storage at room temperature. Similarly, four weeks (one month) at 50°C is equivalent to 1.5 years at room temperature, and eight weeks (two months) is equivalent to 3.0 years. The temperature of 50°C was set taking into consideration conversion to room temperature using an Arrhenius plot, as well as warehouse storage and sea container transport.

[0073] <Heat generation test of small heating body> The heat generation test was conducted following the method of JIS S4100 "Disposable Heating Pads" under the conditions of an ambient temperature of 20±1°C, a wind speed of 0.5 m / s or less (windless conditions), an ambient humidity of 55-70%, and a temperature of 30±1°C for the heating part of a heating device consisting of a heater and a circulating constant temperature water bath.Since the small heating element is attached directly to the skin when in use, it was attached directly to the surface of the heater and measured.

[0074] Specifically, the heat generation test was performed using a tank-shaped heater measuring W615 x D410 x H60 mm (using an 8 mm thick vinyl chloride plate) placed in a constant temperature room set at a room temperature of 20°C and a humidity of 65%, with hot water circulating at 8 L / min from an adjacent circulating constant temperature water bath, controlling the surface temperature of the heater (vinyl chloride plate) to 30°C.The PET separator was then peeled off from a small heater sample, and a temperature measurement sensor was attached to the hot melt adhesive at approximately the center of the bottom surface, which was then attached to the vinyl chloride plate on the surface of the heater (the temperature measuring device was a Chino Graphic Recorder KR2S00, manufactured by Anritsu Meter Co., Ltd., and the sensor was an ST-22E-005).

[0075] The results are shown in Figures 2 and 3. The evaluation of the results is shown in Tables 3 and 4.

[0076] [Table 3] [Table 4]

[0077] 2 and 3 and Tables 3 and 4 show that, compared to the thermal elements using the temperature control agent of the present invention, the thermal elements using the conventional temperature control agent deteriorate relatively quickly after storage at high temperatures and are unable to maintain their pre-storage performance for long periods of time, whereas the thermal elements using the temperature control agent of the present invention, even those containing small-sized particles, maintained stable and good performance even after long-term storage at high temperatures. In particular, Example 4 is a group of only small-sized particles, and although its evaluation was inferior to that of the other Examples, even those containing some particles of this size (Examples 5 to 7) still obtained good results.

[0078] Furthermore, the degree of temperature drop 1 to 10 minutes after reaching the maximum temperature for each of the heating elements of the Examples tended to be smaller than that for the heating elements of the Comparative Examples. Furthermore, the heating duration from reaching 40°C until the temperature dropped below 40°C also tended to be longer for the heating elements of the Examples. The temperature drop rate was calculated using the following formula: Temperature drop rate (%) = {(maximum heat generation temperature - temperature at a certain point) / maximum heat generation temperature} × 100 (Equation 2)

[0079] <Production of Heat-Generating Composition (2)> The raw materials for the heat-generating composition were iron powder (Höganäs Japan Co., Ltd., reduced iron powder "InSIP"), activated carbon (Dainen Co., Ltd., activated carbon (wet carbon) "PL-1P (30% wet)", vermiculite (Vermitech Co., Ltd., "No. 1"), water-absorbent polymer (Sanyo Chemical Co., Ltd., polyacrylate resin "ST-500D*"), sodium chloride (Nihonkaisui Co., Ltd. Powdered salt (EF-300), water, and one of the temperature control agents prepared above were mixed with 56 parts of iron powder, 8.9 parts of activated carbon (wet), 5.2 parts of vermiculite, 2.6 parts of water-absorbent polymer, 3.6 parts of sodium chloride, 23.7 parts of water, and 10 or 20 parts of the temperature control agent (all "parts" are by weight) to produce a heat-generating composition. Specifically, the weighed ingredients were sealed in a PE bag and then shaken vigorously for 30 seconds to thoroughly mix the ingredients and eliminate uneven distribution of the ingredients. The composition of each heat-generating composition sample is shown in Table 5.

[0080] [Table 5]

[0081] <Manufacturing disposable body warmers> The exothermic composition prepared above was placed in a packaging material to prepare a disposable warmer body warmer. 35 g of the heat-generating composition was placed in a ventilation material (Kohjin Film & Chemicals Co., Ltd.) and a PET spunlace nonwoven fabric (weight 30 g / m 2 ) / Porous film 70μm) as the surface material, and adhesive material (Ferric Co., Ltd. Composition: Paper separator 40g / m 2 The contents were placed in a 95mm x 130mm bag with a backing of acrylic adhesive 23µm / PE film 60µm, and the bag was sealed with heat to form a hand warmer. The prepared body warmers were sealed in airtight outer bags (PET 12 μm / aluminum foil 7 μm / LLDPE 50 μm (TOHO Kako Co., Ltd.)) and used as heating units for Examples 8 to 10 and Comparative Examples 8 to 10, respectively.

[0082] <Heat generation test for hand warmers> The heat generation test was performed in a constant temperature and humidity room with an ambient temperature of 20±1°C, a wind speed of 0.5 m / s or less (still wind), and an ambient humidity of 55-70%, using a heat generation tester conforming to JIS S4100 "Disposable Hand Warmers." For a certain period of time after the start of heat generation, the temperature was maintained at a level that would not melt the temperature control agent without covering the hand warmer with flannel cloth. To simulate an overheating condition, excessive heat generation was artificially induced by covering the hand warmer with flannel cloth 1.5 or 2 hours after the start of heat generation, causing the temperature control agent to melt. The temperature drop rate was calculated using Equation 2 above. The heat generation patterns of these heating elements are shown in FIGS.

[0083] [Table 6]

[0084] Although the temperature (maximum temperature) at which the temperature rise was stopped by melting the temperature control agent after excessive heat generation was induced in the heating elements of Examples 8 to 10 was the same as that of the heating elements of the comparative example, the rate of subsequent temperature decline was low, and there was a tendency for heat generation to be maintained for a long time even after excessive heat generation was prevented.

[0085] From the above results, it was revealed that the maximum heat generation temperature of the heating element using the heat generating composition containing the temperature control agent of the present invention is hardly affected by long-term storage. Furthermore, even when the same amount of heat generating composition is used in the heating element, the temperature drop after reaching the maximum heat generation temperature is slowed down, and a heating element with a longer heat generation duration than conventional heating elements can be provided.

[0086] Therefore, a heating element using a heat-generating composition containing the temperature control agent of the present invention has higher temperature stability and safety than a heating element using a conventional temperature control agent, and can maintain the designed heat-generating performance for a long period of time. [Explanation of symbols]

[0087] 1. Heat-generating composition 2 Container (main body) 3 Top material 3a sealant 3b Non-woven fabric 3c adhesive 3D release paper

Claims

1. A temperature control agent containing one or more aliphatic compounds selected from the group consisting of higher α-olefin copolymers, paraffin wax, myristyl myristate, polyester polyols, and polyoxyethylene fatty acid diesters is used to control the heat generation temperature of a heating element containing a heat-generating composition that generates heat upon reaction with oxygen, wherein the aliphatic compound has a melting point of 35°C or higher, a water solubility at 20°C of 5 g / 100 mL or less, and is in a particulate form with an average circularity of 0.70 to 1.

0.

2. 2. The temperature control agent according to claim 1, wherein the aliphatic compound is in a particulate form that does not pass through a 325 mesh standard sieve (standard size according to JIS Z8801-1: 44 μm).

3. 2. The temperature control agent according to claim 1, wherein the aliphatic compound is in a particulate form that passes through a 16-mesh standard sieve (standard size according to JIS Z8801-1: 1000 μm).

4. 2. The temperature control agent according to claim 1, wherein the aliphatic compound is in a particulate form that does not pass through a 325 mesh standard sieve (standard dimension according to JIS Z8801-1: 44 μm) but passes through a 16 mesh standard sieve (standard dimension according to JIS Z8801-1: 1000 μm).

5. 1. A heat-generating composition that generates heat upon reaction with oxygen, the heat-generating composition comprising a metal powder, salts, water, activated carbon, and a temperature control agent for controlling the heat generation temperature of the heat-generating composition, wherein the temperature control agent is the temperature control agent according to any one of claims 1 to 4.

6. A heating element comprising the heat-generating composition according to claim 5 and a bag or container containing the heat-generating composition, at least a portion of which is breathable.

7. 7. The thermal body of claim 6, wherein the bag or container is housed in an airtight outer bag that substantially blocks oxygen.

8. 7. The heating element according to claim 6, which is used as either a disposable body warmer or a medical device.

9. The thermal body according to claim 8, wherein the medical device is either a hot compress or a thermal device for stimulating meridians.

10. 5. The method for producing a temperature control agent according to claim 1, further comprising the step of atomizing a molten material obtained by melting the aliphatic compound or the temperature control agent into spherical particles.

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