Heat-generating element precursor, heat-generating element, and moxibustion tool

Abstract

Provided are a heat-generating element precursor, a heat-generating element, and a moxibustion tool that are capable of elongating the heat-generating time even when a heat-generating composition identical to a conventional product is used.　One embodiment of the present invention is a heat-generating composition precursor 100 from which it is possible to form a heat-generating composition that reacts with oxygen in air in the presence of a liquid component to generate heat. The heat-generating composition precursor 100 comprises: a heat-generating composition precursor 10a yet to have the liquid component added thereto; and a cover 20 having a first covering part 20a that has a housing section 24 capable of housing the heat-generating composition precursor 10a, and an opening section 25 for housing the heat-generating composition precursor 10a, and that is made of a non-air permeable packaging material, and having a second covering part 20b that is made of an air-permeable packaging material and that covers the opening section 25 in a flat shape.

Description

Heat generating element precursor, heat generating element, and moxibustion tool

[0001] The present invention relates to a heat generating element precursor, a heat generating element, and a moxibustion tool.

[0002] Heat generating elements that utilize the oxidation reaction of oxidizable metal powders are widely used in medical devices such as hot compresses and meridian stimulating heating devices, as well as in everyday items such as disposable body warmers.

[0003] Here, the heating element contains a heat-generating composition (e.g., containing iron powder, water, salts, activated carbon, etc.) that generates heat upon reaction with oxygen. When the heating element is in use, the heat-generating composition is exposed to the outside air, whereby the oxygen in the outside air comes into contact with the heat-generating composition, causing the oxidation reaction of the metal powder to be oxidized. Specifically, in the above example composition, the water and salts function to accelerate the oxidation rate of the iron powder, and the activated carbon functions to absorb a large amount of oxygen from the air and sustain the oxidation reaction.

[0004] From the viewpoint of preventing deterioration of the heat generating performance of a heat generating element, it is desirable to prevent or prevent the oxidation reaction of the oxidizable metal before use of the heat generating element. Based on this, a manufacturing method has been proposed in which a heat generating composition precursor (a mixture containing water-insoluble components of the heat generating composition, such as iron powder, salts, activated carbon, and a water-retaining material) is formed into a tablet shape, filled into a container made of packaging material, and then water is injected with a syringe (Patent Document 1), and a manufacturing method has been proposed in which water is injected through a water-permeable packaging material (Patent Document 2).

[0005] WO2016 / 063815 publication WO2022 / 034827 publication

[0006] An object of the present invention is to provide a heat generating element and a precursor thereof that can maintain heat generation for a longer period of time.

[0007] The present invention (1) is a heat-generating element precursor comprising: a heat-generating composition precursor capable of forming a heat-generating composition that generates heat by reacting with oxygen in the air in the presence of a liquid component, the heat-generating composition precursor before the liquid component is added; and a covering body having: a first covering portion having a storage portion capable of storing the heat-generating composition precursor and an opening for storing the heat-generating composition precursor, the first covering portion being made of an air-impermeable packaging material; and a second covering portion that flatly covers the opening, the second covering portion being made of an air-permeable packaging material.

[0008] The present invention (2) is a heat-generating element precursor comprising: a heat-generating composition precursor capable of forming a heat-generating composition by reacting with oxygen in the air in the presence of a liquid component, the heat-generating composition precursor being the heat-generating composition precursor before the liquid component is added; a covering body having: a first covering portion having a concave (or convex) storage portion capable of storing the heat-generating composition precursor and an opening for storing the heat-generating composition precursor, the first covering portion being made of an air-impermeable packaging material; and a second covering portion that flatly covers the opening and is made of an air-permeable packaging material. Here, the storage portion has a concave shape when viewed from the opening (when viewing the inside of the storage portion). Furthermore, the storage portion has a convex shape when viewed from above (when viewing the outside of the storage portion). The storage portion has a space capable of storing the heat-generating composition precursor.

[0009] The present invention (3) is a heat generating element precursor comprising: a heat generating composition precursor capable of forming a heat generating composition that generates heat upon reaction with oxygen in the air in the presence of a liquid component, the heat generating composition precursor being the heat generating composition precursor before the liquid component is added; a first covering portion having a first storage portion (storage portion 24 described below) capable of storing the heat generating composition precursor and having a first depth, and an opening for storing the heat generating composition precursor, the first covering portion being made of an air-impermeable packaging material; and a second covering portion covering the opening, the second storage portion having a second depth (the depth is based on the plane of opening 25 described below) different from the first depth, and made of an air-permeable packaging material. The first covering portion has the first storage portion (storage portion 24). The first storage portion has a first depth. The second covering portion has a second storage portion. The second storage portion has a second depth. The first depth and the second depth are different. Here, since the second covering portion is the portion to be applied to the adherend during use, it is preferable that the first depth is greater than the second depth (first depth > second depth). Also, since the relationship of first depth > second depth is sufficient, the second depth may be 0.

[0010] The present invention (4) is a heat-generating element precursor comprising: a heat-generating composition precursor capable of forming a heat-generating composition upon reaction with oxygen in the air in the presence of a liquid component, the heat-generating composition precursor being the heat-generating composition precursor before the liquid component is added; a first covering part made of an easily deformable, gas-impermeable packaging material; and a second covering part made of a gas-permeable packaging material; wherein the heat-generating composition precursor is contained between the first covering part and the second covering part, with the first covering part being deformed by the heat-generating composition precursor. Here, "easily deformable" refers to the degree of deformability that, when the heat-generating composition precursor is pressed against the surface of the first covering part, the pressed surface can deform in the direction of the pressure (based on the surface not pressed). Examples of materials for the first covering part include an extensible (merely stretchable) or stretchable elastomer film.

[0011] The present invention (5) is the heating element precursor according to any one of the present inventions (1) to (4), wherein the first covering portion has at least one ventilation hole.

[0012] The present invention (6) is the heat generating composition precursor according to any one of the present inventions (1) to (5), wherein the heat generating composition precursor contains a swelling agent capable of absorbing a liquid component, and the swelling agent is capable of swelling within the storage section when it absorbs the liquid component.

[0013] The present invention (7) is the heat generating element precursor according to any one of the present inventions (1) to (6), wherein the ratio of the volume of the heat generating composition precursor to the volume of the container is 0.2 or more.

[0014] The present invention (8) is the heating element precursor according to any one of the present inventions (1) to (7), wherein, when the second covering portion faces the object to be heated, air is introduced into the opening through a gap formed between the second covering portion and the object to be heated.

[0015] The present invention (9) is the heating element precursor according to any one of the present inventions (1) to (8), further comprising an adhesive applied to the second covering portion and overlapping a part of the opening.

[0016] The present invention (10) is a heating element in which a liquid component is introduced into the housing of the heating element precursor of any one of the inventions (1) to (9) via the second covering portion.

[0017] The present invention (11) is the heat generating element of the present invention (10), wherein the heat generating composition precursor is in a molded solid form, and when the liquid component is introduced into the storage section, the heat generating composition precursor in the solid form becomes the heat generating composition in a cracked form.

[0018] Invention (12) is the heating element according to any one of Inventions (10) to (11), in which the time during which the heat generation temperature is 40°C or higher (the time until the temperature again reaches 40°C after reaching 40°C) is more than 20 minutes (more preferably 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, or 70 minutes or more; the upper limit is not particularly limited, for example, 200 minutes or less). In addition, the maximum temperature is not particularly limited, for example, 70°C or lower, 65°C or lower, 60°C or lower, or 55°C or lower.

[0019] The present invention (13) is the heat generating element according to any one of the present inventions (10) to (12), wherein at least a part of the second covering portion swells outward due to swelling of the heat generating composition precursor.

[0020] The present invention (14) is a moxibustion tool including any one of the present inventions (10) to (13).

[0021] First, the heating element of the present invention relates to a packaging material for a covering that houses a heat-generating composition, with the first covering being made of an air-impermeable packaging material, while the second covering being made of an air-permeable packaging material. Therefore, during use, oxygen is supplied to the heat-generating composition inside through the second covering. When the second covering is applied to the object to be heated, the configuration of the present invention results in a small or almost non-existent gap between the second covering and the object to be heated. As a result, oxygen is continuously supplied to the heat-generating composition in small amounts, resulting in the heat-generating reaction being sustained for a long period of time. Furthermore, while the heat generated by the heat-generating composition evaporates the liquid components within the composition, the first covering being made of an air-impermeable packaging material prevents the liquid components from evaporating to the outside, thereby retaining the heat of vaporization lost by evaporation and retaining a sufficient amount of the liquid components necessary for the reaction within the covering. From the above, the heating element of the present invention achieves the effect of maintaining heat generation for a longer period of time.

[0022] Furthermore, the heat generating element precursor according to the present invention has the effect of being useful as an intermediate product for obtaining a heat generating element having the above-mentioned effects. Furthermore, since the heat generating element precursor according to the present invention is substantially free of liquid components, it has the effect of preventing oxidation reactions from proceeding substantially, and can be stored in this state for a long period of time without being sealed.

[0023] FIG. 1 is a perspective view showing an example of a heating element precursor / heating element according to this embodiment. FIG. 2 is a cross-sectional view schematically showing a cross section of the heating element precursor according to this embodiment, taken along the arrow A-A in FIG. 1. FIG. 3 is a cross-sectional view schematically showing a cross section of the heating element precursor according to this embodiment, taken along the arrow A-A in FIG. 1 (however, this is an example of a heating element precursor having a different shape from the heating composition precursor of FIG. 2). FIG. 4 is a cross-sectional view schematically showing a cross section of the heating element according to this embodiment, taken along the arrow A-A in FIG. 1. FIG. 5 is a plan view schematically showing the heating element according to this embodiment in FIG. 4, viewed from the underside (adhesion surface) after the second covering portion has been peeled off. FIG. 6 is a cross-sectional view schematically showing an example of a heating element precursor according to this embodiment, in which ventilation holes are formed in the first covering portion. FIG. 7 is a view illustrating various patterns of adhesive applied to the heating element according to this embodiment. The shaded areas indicate areas where the adhesive is present, and the open areas indicate areas where the adhesive is not formed. The dotted line indicates the boundary with the periphery of the opening. The area inside the dotted line is the opening, and the area outside is the periphery. FIG. 8 is a diagram showing the flow of the manufacturing method of the heating element according to the present embodiment. FIG. 9 is a diagram showing the heat generation patterns of the heating elements according to Example 1 and Comparative Examples 1 and 2. FIG. 10 is a diagram showing the heat generation patterns of the heating elements according to Example 2 and Comparative Examples 1 and 2. FIG. 11 is a diagram showing the heat generation patterns of the heating elements according to Example 3 and Comparative Examples 1 and 2. FIG. 12 is a diagram showing the heat generation patterns of the heating elements according to Example 4 and Comparative Examples 1 and 2. FIG. 13 is a diagram showing the heat generation patterns of the heating elements according to Example 5 and Comparative Examples 1 and 2. FIG. 14 is a diagram showing the heat generation patterns of the heating elements according to Example 6 and Comparative Examples 1 and 2. FIG. 15 is a diagram showing the heat generation patterns of the heating elements according to Example 7 and Comparative Examples 1 and 2.

[0024] The "heat generating element precursor" and "heat generating element" according to one embodiment of the present invention will be described in detail below. Here, the "heat generating element" generally refers to a heat generating composition housed in a covering (described in detail below) (including a case packaged in an outer bag), and the "heat generating element precursor" refers to the heat generating composition in a state before a liquid component is introduced (heat generating composition precursor) housed in a covering (described in detail below).

[0025] The "heat generating element precursor" and "heat generating element" will be described in detail below. Here, the "heat generating element precursor" or "heat generating element" according to this embodiment has a surface (hereinafter, for convenience, also referred to as the "lower surface" or "adhesive surface") that is applied to the body, clothing, or other object to which heat is to be applied (heating object), and at least one opposite surface (hereinafter, for convenience, also referred to as the "upper surface"). For ease of explanation, in this specification, the body, clothing, or other object to which heat is to be applied (heating object) may be referred to as the "body" or "body, etc." However, the object to which the heat generating element precursor, heat generating element, or moxibustion device according to the present invention is applied is not limited to the body.

[0026] The shapes, manufacturing methods, uses, etc. of the "heat generating element precursor" and "heat generating element" of this embodiment will be specifically organized and explained below.

[0027] 1. Shape, Structure, Size, and Thickness 1-1. Shape The overall shape of the heating element precursor / heating element according to this embodiment is not particularly limited, except that it is preferable that the opening of the first covering portion (upper surface) is flatly covered by the second covering portion (lower surface). Here, "flat" in this specification and claims includes not only a completely flat shape but also a substantially flat shape that bulges outward (toward the opposite side from the first covering portion) to some extent (it can also be said that the second covering portion has a storage portion). Here, "substantially flat" refers to a bulge (e.g., see FIG. 4) of, for example, 100%, 75%, 50%, 40%, or 30% or less relative to the height of the storage portion of the first covering portion. Here, the "container height" refers to "h" in the figure if the height is constant as shown in FIG. 2 , or to the average height if the height is not constant (not shown). (Here, the "average height" is the value obtained by dividing the volume of the "container of the first covering" by the area of ​​the "opening of the first covering"). Here, it is preferable that the second covering of the heating element precursor is completely flat. With this configuration, when a liquid component is introduced into the interior through the second covering of the heating element precursor, the flatness of the second covering allows the liquid component to be introduced uniformly to the surface (second covering) (as a result, the liquid component can be introduced approximately uniformly into the heating element precursor). On the other hand, it is preferable that the second covering of the heating element is approximately flat with a slight bulge. With this configuration, particularly when the heating object is a flexible object (e.g., skin), the bulging portion of the second covering sinks into and abuts against the flexible object, further reducing the gap between the second covering and the heating object. Furthermore, since the second covering is in closer contact with the heating object, heat is less likely to escape. From the above, it is possible to further extend the heat generation time.

[0028] Incidentally, when considering the use as a moxibustion tool, the heat generating element precursor / heat generating element according to this embodiment preferably has a convex three-dimensional shape (moxibustion shape), as shown in Figure 1 (a perspective view showing an example of the heat generating element precursor / heat generating element according to this embodiment). The shape of the heat generating element precursor / heat generating element according to this embodiment when viewed from above or below is not particularly limited, and examples include a substantially circular shape, an elliptical shape, a polygonal shape, etc. However, when considering that the heat generating element precursor / heat generating element will be used by being directly attached to the skin, a substantially circular shape or an elliptical shape without corners is preferred.

[0029] <1-2. Structure> The heat generating element precursor / heat generating element according to this embodiment comprises a heat generating composition precursor / heat generating composition; a covering body having a first covering portion having a housing portion capable of housing the heat generating composition precursor / heat generating composition and an opening for housing the heat generating composition precursor; and a second covering portion that flatly covers the opening; and preferably an adhesive body that is applied to the second covering portion and overlaps with a portion of the opening. In addition to these elements, the heat generating element precursor / heat generating element according to this embodiment may also comprise other elements as needed, such as a release portion (e.g., release paper) for covering the surface of the adhesive body. Below, the heat generating element precursor and the heat generating element will be explained separately as appropriate.

[0030] (1-2-1. Overall Structure: Heat-Generating Element Precursor) Figures 2 and 3 are cross-sectional views schematically showing a heat-generating element precursor 100 according to one example of the present embodiment. As shown in Figures 2 and 3, the heat-generating element precursor 100 according to one example of the present embodiment comprises a heat-generating composition precursor 10a, a coating 20, and an adhesive body 30. Here, the heat-generating composition precursor 10a in Figure 2 has a cylindrical shape (with a flat bottom), and the heat-generating composition precursor 10a in Figure 3 has a tablet shape (with a curved bottom).

[0031] FIG. 6 is a cross-sectional view schematically illustrating an example of the heat generating element precursor 100 according to this embodiment, in which a vent hole 40 is formed in the first covering portion 20a (a modified example of the heat generating element precursor according to FIG. 2). As shown in FIG. 6, the first covering portion 20a may have at least one vent hole 40. The vent hole 40 facilitates the escape of air from the housing portion 24 when a liquid component is introduced into the heat generating element precursor 100 (providing an escape route for the internal air). As a result, the liquid component is introduced fairly uniformly throughout the heat generating composition precursor 10, enabling stable heat generation for a longer period of time and preventing the injected liquid component from overflowing on the production line. Additionally, if the first covering portion has at least one vent hole, the liquid component may be introduced through the vent hole in the first covering portion.

[0032] (1-2-2. Overall Structure: Heating Element) Fig. 4 is a cross-sectional view schematically showing a heating element 200 according to one example of the present embodiment. As shown in Fig. 4, the heating element 200 according to the present embodiment includes a heat-generating composition 10b, a coating 20, and an adhesive body 30.

[0033] (1-2-3. Element: Heat-generating Composition Precursor / Heat-generating Composition) Heat-generating Composition Precursor The heat-generating composition precursor according to this embodiment is not structurally limited as long as it has the composition described below. However, the heat-generating composition precursor according to this embodiment is preferably a molded body, and among molded bodies, a pressure-molded body (e.g., a tablet-molded body) is particularly preferred. By using a molded body or a pressure-molded body, it is possible to introduce a larger amount of heat-generating composition precursor into the coating body compared to using an unmolded powdered heat-generating composition precursor. In addition, by using a molded heat-generating composition precursor, when introducing a liquid component from the second coating portion during production of the heat-generating element, the liquid component introduced into the interior spreads along the surface of the molded heat-generating composition precursor, allowing the liquid component to be introduced more evenly into the heat-generating composition precursor. Therefore, when the heat-generating element is in use, it is possible to reduce non-reactive portions in the heat-generating composition (portions where no liquid component is introduced and therefore no reaction with oxygen is expected), thereby enabling the heat generation time to be sustained for a longer period of time. In addition, when a molded heat-generating composition precursor is used, it is easier to transport and install tablets using air or a magnet. The shape of the exothermic composition precursor as a molded product is not particularly limited, and examples of the shape of the exothermic composition precursor as a molded product include a disk, a tablet, a prism, a pyramid, a cube, a rectangular parallelepiped, a cylinder, a cone, an elliptical cylinder, a lozenge shape with a hole in the center, a sphere, and the like.

[0034] Heat-generating Composition The heat-generating composition according to this embodiment is obtained by introducing a liquid component into a heat-generating composition precursor. Here, as shown in FIG. 4, when a liquid component is introduced into a molded heat-generating composition precursor 10a (FIG. 2), a liquid-absorbing component (e.g., a swelling agent) in the heat-generating composition precursor absorbs the liquid component, causing a rapid increase in the volume of the liquid-absorbing component. The lower limit of the volume expansion rate from the heat-generating composition precursor (volume of heat-generating composition / volume of heat-generating composition precursor × 100%) is, for example, 150% or more, 175% or more, 200% or more, 225% or more, or 250% or more, and the upper limit is, for example, 500% or less, 450% or less, 400% or less, 350% or less, or 300% or less. Furthermore, as a result of this sudden increase in volume, cracks 11 appear in the molded shape, resulting in a heat-generating composition with a slightly collapsed shape, as shown in FIG. 4. To elaborate on this point, when a liquid component is added to a heat-generating composition precursor containing a liquid-absorbing component, the heat-generating composition precursor typically tends to shatter due to swelling of the liquid-absorbing component. On the other hand, when the heat-generating composition precursor is contained within a coating, as in this embodiment, swelling of the heat-generating composition precursor due to the addition of a liquid component is restricted by the inner wall of the coating. Therefore, it is presumed that cracks occur due to internal stress caused by the heat-generating composition precursor being unable to shatter. Figure 5 is a schematic plan view of the heat-generating element 200 according to this embodiment shown in Figure 3, viewed from the underside (attached surface) after the second coating portion 20b has been peeled off. As shown in Figures 4 and 5, the formation of cracks 11 in the heat-generating composition 11b allows air to be supplied not only to the outside but also to the inside of the heat-generating composition 11b, thereby substantially increasing the amount of reacting heat-generating composition and allowing the heat generation time to be maintained for a longer period of time.

[0035] (1-2-4. Element: Covering Body) As described above, the covering body according to this embodiment has the first covering portion and the second covering portion. Here, the covering body according to this embodiment will be described in detail with reference to FIGS. 2 and 4.

[0036] Entire Covering Body As shown in FIGS. 2 and 4 , the covering body 20 according to this embodiment has a first covering portion 20a and a second covering portion 20b. The first covering portion 20a includes surfaces other than the surface facing the body, i.e., an upper surface 21 (external upper surface, inner upper surface) and side surfaces (external side surfaces, inner side surfaces). The second covering portion 20b is applied to the body, etc., so as to face the body, etc. (e.g., via an adhesive 30). Here, the second covering portion 20b includes a surface that is applied to the body, etc., i.e., a lower surface (attachment surface) 22. The covering body 20 has a peripheral portion 23 that protrudes outward. The first covering portion 20a and the second covering portion 20b are joined at the peripheral portion 23. The first covering portion 20a and the second covering portion 20b will be described below.

[0037] First Covering Part The first covering part 20a has a concave (when viewed from the opposite side in FIG. 2) containing part 24 (for example, composed of an inner upper surface and an inner side surface) that can contain the exothermic composition precursor 10a / exothermic composition 10b. The first covering part 20a has an opening 25 for containing the exothermic composition precursor 10. Here, as shown in FIG. 2, the inner upper surface and the opening of the first covering part face each other. The first covering part 20a can be manufactured, for example, by processing a resin sheet using a method such as thermoforming or vacuum forming. Here, the surface area of ​​the containing part 24 (the total surface area of ​​the inner upper surface and inner side surface that constitute the containing part 24) is preferably 250 to 2,500 mm ２ , more preferably 450 to 1,600 mm ２ , more preferably 600 to 1,300 mm ２ The width of the housing portion 24 (the distance between the opposing inner side walls, for example, the inner diameter when the first covering portion is cylindrical, the average value calculated from the smallest and largest inner diameters when the first covering portion is truncated cone-shaped, the major axis and minor axis when the first covering portion is elliptical cylindrical, and the long side and short side when the first covering portion is rectangular) is preferably 7 to 30 mm, more preferably 10 to 25 mm, and even more preferably 13 to 22 mm. Furthermore, the ratio of the surface area to the height of the housing portion inside the first covering portion (surface area of ​​housing portion / height of housing portion: mm ２ / mm) is preferably 40 to 210, more preferably 60 to 190, and even more preferably 80 to 170. Furthermore, the ratio of the width to the height of the housing section inside the first covering section (width of housing section / height of housing section: mm / mm) is preferably 0.8 to 5.0, more preferably 1.2 to 4.0, and even more preferably 1.5 to 3.5. Note that, when the width varies in the height direction, the "width" here refers to the average width (the diameter of a circle when the average area, which is the value obtained by dividing the volume of the housing section by the height of the housing section, is considered to have that average area). When the preferred range is as described above, heat generation for a longer period of time can be achieved.

[0038] Here, as described above, the first covering portion (non-gas-permeable packaging material) may or may not have ventilation holes. When ventilation holes are present, the shape of the ventilation holes is not particularly limited, and examples include one or a combination of circular, rectangular (e.g., square), slit, etc. Furthermore, when ventilation holes are present, the location of the ventilation holes is not particularly limited as long as they are in the storage portion, and they may be on the top surface and / or side surface. Furthermore, when ventilation holes are present, the size of the ventilation holes is preferably 0.1 to 1.5 mm, more preferably 0.2 to 1.2 mm, and even more preferably 0.3 to 1.0 mm. When the ventilation holes are not circular, the size is taken as the size at the longest point (for example, the diagonal in the case of a square, or the slit length (length of the vertical slit) in the case of a slit). Furthermore, when ventilation holes are present, the number of ventilation holes is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 2. In addition, when the housing has ventilation holes, the ratio of the total area of ​​the ventilation holes to the surface area of ​​the housing 24 (total area of ​​ventilation holes / surface area of ​​housing: mm ２ / mm ２ × 100%) is preferably 0.0005 to 2.8%, more preferably 0.002 to 1.8%, and even more preferably 0.005 to 1.3%. Within such a preferred range, heat generation for a longer period of time is possible. The ventilation holes function to vent air when water is poured from the nonwoven fabric side (second covering portion side). On the other hand, when water is poured from the ventilation holes, the nonwoven fabric side functions to vent air.

[0039] The first covering may be made of a material that is easily deformable. As described above, "easily deformable" refers to a degree of deformability that allows the pressed surface of the first covering to deform in the direction of the heat-generating composition precursor when the heat-generating composition precursor is pressed against the surface of the first covering (based on the surface that is not pressed) (for example, deformation in the direction of the pressed surface by at least ⅓, at least ½, at least ⅔, or at most 1 / 2 of the thickness of the heat-generating composition precursor). When such a material is used, the aforementioned process of deforming the first covering and then accommodating the heat-generating composition precursor in the deformed portion (i.e., the accommodation portion or opening), such as thermoforming or vacuum forming, is not required. That is, the deformation of the first covering and the accommodation of the heat-generating composition precursor are simultaneously achieved by pressing the heat-generating composition precursor against the surface of the first covering. Then, with the heat-generating composition accommodated in the first covering, the second covering is joined to the first covering to obtain a heat-generating element precursor.

[0040] Second Covering Portion The second covering portion 20b is joined to the first covering portion 20a so as to cover the opening 25 of the first covering portion 20a in a flat manner.

[0041] (1-2-5. Element: Adhesive) The heating element precursor and heating element according to this embodiment preferably have an adhesive on the surface of the second covering portion opposite the first covering portion. For example, as shown in FIG. 2 , the adhesive 30 is applied to the attachment surface of the second covering portion 20b. The adhesive 30 allows the second covering portion 20b to face the body or the like when applied to the body or the like. The adhesive 30 is applied to the second covering portion 20b, for example, so as to overlap with a portion of the opening 25 of the first covering portion 20a. Therefore, by changing the position, shape, and size at which the adhesive 30 is applied, the area of ​​the region where the first covering portion 20a overlaps with a portion of the opening 25 can be adjusted. This also makes it possible to control the area of ​​the region of the opening 25 that does not overlap with the first covering portion 20a, i.e., the area of ​​the region of the opening 25 where ventilation is substantially possible (ventilation region 26). Controlling the area of ​​the adhesive in this manner also makes it possible to control the heating temperature and heating time. Furthermore, by providing the adhesive body 30, it is possible to stably maintain a gap between the second covering part 2b and the body, etc. As a result, the amount of air introduced into the interior can be controlled to a small amount, making it possible to maintain the oxidation reaction time for a longer period of time. In this way, by providing the adhesive body in the second covering part so that it overlaps with a part of the opening, it is possible to ensure that the exothermic reaction continues for a long period of time while also ensuring that the adhesive body adheres to the object to be heated.

[0042] FIG. 7 illustrates various patterns of the adhesive body 30 of the heating element precursor and heating element 200 according to this embodiment. The shaded areas indicate areas where the adhesive body 30 is present, and the open areas indicate areas where the adhesive body 30 is not formed. The dotted line indicates the boundary between the opening 25 and the peripheral edge 23. The area enclosed by the dotted line is the opening 25, and the area enclosed by the dotted line is the peripheral edge 23. The position, size, and shape of the adhesive body 30 are not particularly limited. For example, as shown in FIG. 7 , the adhesive body 30 can be applied in any position, size, or shape, such as a stripe, circle, or rectangle. Here, as described above, if the second coating portion of the heating element bulges slightly outward (see, for example, FIG. 4 ), when this is applied to an adherend, the heating element tends to peel off easily from the adherend. Taking this into consideration, it is preferable for the adhesive body to be present in approximately the center of the rear surface (adherend surface) of the heating element (for example, in the example of FIG. 7 , the third and fifth from the left in the top row, and the first to third from the left in the bottom row).

[0043] <1-3. Size and Thickness> (1-3-1. Heat-generating Composition Precursor) The size of the heat-generating composition precursor according to this embodiment is not particularly limited, and can be of a size and shape depending on the application of the heat-generating element. For example, when producing a heat-generating element to be used as a moxibustion tool, the heat-generating composition precursor is preferably in a solid form with a width of 2 mm to 30 mm (diameter if cylindrical) and a height of 2 mm to 15 mm. For example, when the heat-generating composition precursor is cylindrical as shown in Figure 2, A in the figure represents the width and B represents the height, and when the heat-generating composition precursor is tablet-shaped as shown in Figure 3, C represents the width and D represents the height. Note that when the width and height are not constant as in Figure 3, the width is the average width, and the height is the height at the maximum height. Here, the heat-generating composition precursor in a solid form (preferably a molded product) preferably has a certain thickness, and specifically, the height relative to the surface area of ​​the heat-generating composition precursor (height / surface area: mm / mm ２ ) is preferably 0.008 to 0.09, more preferably 0.014 to 0.08, and even more preferably 0.02 to 0.07. When the area varies in the height direction, the "surface area" used here refers to the average area (the average area obtained by dividing the volume of the heat-generating composition precursor by the height).

[0044] (1-3-2. Cover) The size of the cover according to this embodiment is not particularly limited and may be determined appropriately based on the amount of exothermic composition precursor contained therein, the area to be heated, and other factors. For example, as shown in FIGS. 2 and 4 , if the exothermic composition precursor 10a contains a swelling agent, the swelling agent will swell after the liquid component is injected, resulting in a larger volume of the exothermic composition 10b than the original volume of the exothermic composition precursor 10a. In addition, if the volume of the cover is too small, there is a risk that the liquid component will overflow before being absorbed by the exothermic composition precursor 10a. Taking these factors into consideration, as shown in FIG. 2 , it is preferable that at least the exothermic element precursor 100 has a space within the housing 24 (a gap between the exothermic composition precursor 10a and the first housing 20a). That is, as shown in FIG. 2 , it is preferable that the diameter of the housing upper surface 21 of the first housing 20a and / or the housing height h are slightly larger than the diameter and / or height of the exothermic composition precursor 10a, respectively. For example, when manufacturing a heating element to be used as a moxibustion tool, the diameter of the upper surface 21 of the first covering portion 20a is preferably 5 mm to 40 mm. The height h of the housing portion of the first covering portion 20a is preferably 5 mm to 20 mm. The thicknesses of the first covering portion and the second covering portion are not particularly limited, but are generally about 6 to 800 μm, and preferably about 20 to 700 μm.

[0045] (1-3-3. Volume Ratio) The ratio of the volume of the exothermic composition precursor 10a to the volume of the storage section 24 has a lower limit of preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more, and an upper limit of preferably 0.7 or less, more preferably 0.6 or less, and even more preferably 0.5 or less. If this volume ratio is within the preferred range, when introducing the liquid component into the exothermic composition precursor, the liquid component can be introduced approximately uniformly throughout the exothermic composition, and the exothermic composition (the portion of the exothermic composition precursor into which the liquid component has been introduced) can be maximized, thereby making it possible to extend the oxidation reaction time.

[0046] (1-3-4. Adhesive Body) When the adhesive body according to this embodiment is applied to a heating element, the adhesive body is applied to the second covering portion 20b so that the ratio of the area of ​​the ventilation region 26 to the area of ​​the opening 25 is preferably 0.05 or more, more preferably 0.1 or more, and even more preferably 0.2 or more, and is preferably 1 or less, more preferably 0.95 or less, more preferably 0.9 or less, and even more preferably 0.85 or less. By setting this ratio within this preferred range, when the heating element is applied to an object to be heated, the amount of oxygen introduced into the heating element can be reduced to a preferred range, thereby extending the oxidation reaction time. Note that when an adhesive body is applied to a heating element, a ratio of the area of ​​the ventilation region 26 to the area of ​​the opening 25 of 1 means that the adhesive body is not applied to the ventilation region, but is applied to at least a portion of the peripheral edge of the heating element (i.e., the welded portion around the opening, as shown by 23 in FIG. 2). The thickness of the adhesive body is generally preferably 5 to 250 μm, more preferably 10 to 220 μm, and even more preferably 20 to 200 μm.

[0047] 2. Materials, Ingredients, and Formulation (2-1. Heat-generating Composition Precursor) The heat-generating composition precursor according to this embodiment contains an oxidizable metal powder, one or more salts, activated carbon, a swelling agent, and, as necessary, various additional ingredients. Each ingredient is described in detail below.

[0048] - Oxidizable Metal Powder The oxidizable metal powder according to this embodiment is not particularly limited as long as it is a metal powder that generates heat of oxidation, and is generally iron powder. Specific examples of oxidizable metal powder include iron powder (reduced iron, cast iron, atomized iron, iron sulfate), aluminum powder, zinc powder, manganese powder, magnesium powder, calcium powder, etc. Here, the exothermic composition precursor contains the oxidizable metal powder in a range of about 10% by mass to about 80% by mass, preferably about 15% by mass to about 70% by mass, based on the total mass of the exothermic composition precursor. In this specification, "%" means "mass %" unless otherwise specified.

[0049] Salts The salts of this embodiment may be any electrolyte that dissolves in the liquid component and ionizes. Specific examples of salts of this embodiment include salts of alkali metals (e.g., sodium, potassium, etc.), alkaline earth metals (e.g., magnesium, calcium, etc.), and other metals (e.g., manganese, copper, etc.) with inorganic acids (e.g., chlorides, sulfates, carbonates, nitrates, etc.), salts of organic acids (e.g., acetates, etc.), and mixtures thereof. Among these salts, sodium chloride, calcium chloride, magnesium chloride, cupric chloride, and mixtures containing them are preferred. Here, the heat-generating composition precursor preferably contains salts in a range of about 0.5% to about 10% by mass, more preferably about 1% to about 5% by mass, based on the total mass of the heat-generating composition precursor.

[0050] Activated Carbon The activated carbon according to the present embodiment is not particularly limited. Specific examples of activated carbon according to the present embodiment include activated carbon derived from plant materials such as coconut shells and wood, and activated carbon derived from animal materials and other materials. Here, the exothermic composition precursor preferably contains activated carbon in an amount of about 0.5% to about 25% by mass, more preferably about 0.5% to about 20% by mass, and even more preferably about 1% to about 15% by mass, based on the total mass of the exothermic composition precursor.

[0051] Swelling Agent: The swelling agent of this embodiment is not particularly limited as long as it absorbs a liquid component and expands in volume. Specific examples of swelling agents of this embodiment include hydrophilic polymers such as dried gel, gelatin, and agar, and hydrophobic polymers whose swelling is not easily suppressed by inorganic salts. A particularly suitable swelling agent is a polymer (superabsorbent resin) made of a crosslinked acrylate salt. Here, the heat-generating composition precursor preferably contains less than about 45% by weight of swelling agent, more preferably about 0.1% to about 30% by weight, even more preferably about 0.5% to about 20% by weight, and particularly preferably about 1% to about 10% by weight, based on the total weight of the heat-generating composition precursor.

[0052] Additional Components The additional components according to this embodiment include binders, temperature control agents, pH adjusters, oxidation reaction accelerators, hydrogen gas inhibitors, extenders, fillers, anti-caking agents, thickeners, surfactants, etc. One or more of these may be used as needed. Among these, the binders, temperature control agents, and pH adjusters will be described in detail. First, the binder according to this embodiment is an agent for forming the powder raw material into a solid form. Specific examples of binders according to the present invention include cellulose (e.g., crystalline cellulose), starch, dextrin, sucrose esters, Teflon (registered trademark), lactose, polyethylene glycol, carboxymethylcellulose, calcium silicate, synthetic hydrotalcite, magnesium aluminometasilicate, dried aluminum hydroxide gel, corn starch, calcium carbonate, gum arabic, gelatin, guar gum, kaolin dibasic calcium phosphate, tribasic calcium phosphate, polyethylene oxide, xanthan gum, ammonium methacrylate copolymer, vinyl acetate copolymer, syrup, povidone, lactitol, calcium sulfate, algin, and alginic acid. When molding (e.g., tableting), the exothermic composition precursor preferably contains about 5% to about 50% by weight, more preferably about 5% to about 45% by weight, and even more preferably about 10% to about 40% by weight of binder, based on the total weight of the exothermic composition precursor. The temperature control agent according to the present invention controls the upper limit of the exothermic temperature. Specific examples of the temperature control agent according to this embodiment include aliphatic compounds having a melting point of 35°C or higher and 70°C or lower and a water solubility of 5 g / 100 mL or less at 20°C, more specifically higher α-olefin polymers (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, preferably side-chain crystalline polyolefins having a certain long-chain α-olefin in the side chain), various paraffin waxes such as vegetable, animal, or petroleum-based, myristyl myristate, polyester polyol, polyoxyethylene fatty acid diester, etc. The heat-generating composition precursor preferably contains 0 to about 40% by mass, more preferably about 0.1% to about 35% by mass, and even more preferably about 0.5% to about 30% by mass of the temperature control agent, based on the total mass of the heat-generating composition precursor.Furthermore, the pH adjuster according to this embodiment is not particularly limited as long as it functions to prevent the outer bag from swelling with hydrogen gas during storage. Specific examples of pH adjusters according to this embodiment include sodium sulfite, sodium polyphosphate, sodium thiosulfate, etc. The heat-generating composition precursor preferably contains the pH adjuster in an amount ranging from about 0.01% by mass to about 5% by mass, more preferably from about 0.1% by mass to about 2% by mass, based on the total mass of the heat-generating composition precursor.

[0053] (2-2. Heat-generating composition) The heat-generating composition according to this embodiment is obtained by adding a liquid component to the heat-generating composition precursor described above. The liquid component will be explained below.

[0054] Liquid Component The liquid component of this embodiment is not particularly limited as long as it is a medium capable of forming a liquid that dissolves and ionizes salts, destroys the iron oxide film to allow the iron oxidation reaction to continue, and conducts electricity within the heat-generating composition. A suitable example of the liquid component of this embodiment is water. Examples of water include ion-exchanged water, pure water, tap water, and industrial water. The liquid component may also contain other components (e.g., salts, pH adjusters (e.g., sodium sulfite)) as needed. The amount of liquid component added to the heat-generating composition precursor is preferably 10 to 50 parts by mass, more preferably 15 to 40 parts by mass, even more preferably 17.5 to 35 parts by mass, and most preferably 20 to 30 parts by mass per 100 parts by mass of the heat-generating composition precursor. In terms of the content of the liquid component in the exothermic composition, the exothermic composition preferably contains the liquid component in a range of about 1% by mass to about 40% by mass, more preferably about 10% by mass to about 30% by mass, based on the total mass of the exothermic composition precursor.

[0055] - Suitable blending of the heat-generating composition To summarize the above, the suitable blending of the heat-generating composition according to this embodiment is, based on the total mass of the heat-generating composition, 15% by mass to 60% by mass of oxidizable metal powder, 1% by mass to 4% by mass of salts, 2% by mass to 10% by mass of activated carbon, 10% by mass to 40% by mass of liquid component (e.g., water), 1% by mass to 10% by mass of swelling agent, 12% by mass to 20% by mass of binder, and 0% by mass to 25% by mass of temperature control agent.

[0056] (2-3. First covering portion) The first covering portion is made of an air-impermeable packaging material. This allows liquid components (e.g., water or water vapor) in the heat-generating composition to remain and condense on the inner surface of the first covering portion, making it difficult for them to be released from within the heat-generating composition. As a result, it is possible to provide a heat-generating element or moxibustion tool that generates heat for a longer period of time at high temperatures. Here, "air-impermeable packaging material" refers to a packaging material having an air permeability of 80,000 seconds / 100 cc or more, for example. The air permeability is a value measured according to JIS P8117:2009 (Gurley method). However, when the non-air-permeable packaging material has air vents, the air permeability of the first covering portion having the air vents preferably has a lower limit of, for example, 4 seconds / 100 cc, 5 seconds / 100 cc, or 6 seconds / 100 cc, and a preferred upper limit of, for example, 60 seconds / 100 cc, 80 seconds / 100 cc, or 100 seconds / 100 cc. Specific examples of materials for the non-air-permeable packaging material include polyethylene, polypropylene, polyester, polyamide, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyurethane, polystyrene, ethylene-vinyl acetate copolymer, polycarbonate, rubber hydrochloride, and the like, either alone or in combination. Furthermore, non-air-permeable packaging materials can also be used, such as paper, aluminum sheets, polyurethane foam, artificial fibers such as polyvinyl chloride, cloth such as cotton, linen, or silk, and laminates thereof. When heat sealing is used as the joining method to the second covering, the material of the first covering is preferably selected in relation to the material of the second covering. Furthermore, the first covering does not need to be composed solely of an impermeable packaging material; for example, it may be a composite of an impermeable packaging material and a nonwoven fabric. Furthermore, when the above-mentioned easily deformable material is used as the first covering, the material of the first covering is preferably a ductile material or a stretchable material. Specific examples include olefin-based elastomers, urethane-based elastomers, and rubber-based elastomers.

[0057] (2-4. Second Covering Portion) The second covering portion is composed of a gas-permeable packaging material. This allows oxygen to be supplied from the outside to the heat-generating composition when the heat-generating element is in use. Furthermore, if this gas-permeable packaging material is permeable to liquid components (e.g., water-permeable), even during the manufacture of the heat-generating element, the liquid component can be introduced into the packaging material through the second covering portion by, for example, spraying a liquid component onto the surface of the gas-permeable packaging material opposite the surface facing the first covering portion. Here, the gas-permeable packaging material is not particularly limited as long as it can introduce air from outside the heat-generating element into the interior of the heat-generating element, and examples thereof include packaging materials with an air permeability of 100 seconds / 100 cc or less (JIS P8117:2009, Gurley method) (e.g., 50 seconds or less, 25 seconds or less, 10 seconds or less, 5 seconds or less, 1 second or less, 0.5 seconds or less). Examples of the structure of the second covering portion include nonwoven fabrics, woven fabrics, single-layer or laminated porous films or sheets, pinhole-punched single-layer or laminated non-porous films or sheets, and combinations thereof. Specific examples of breathable packaging materials (nonwoven fabrics and woven fabrics) include those used in technical fields such as heating elements 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, linen, silk, and wool. Examples of nonwoven fabrics include spunbond, thermalbond, and spunlace. Among these, nonwoven fabrics are preferred because they allow air to be introduced from the side of the second covering portion (parallel to the surface of the adherend when attached to the adherend). Note that, if breathability from the side of the nonwoven fabric (second covering portion) is ensured, an embodiment in which an adhesive layer is provided on the entire back surface of the heating element can also be envisioned. Here, the basis weight of the nonwoven fabric is generally about 10 g / m. ２ ~about 800g / m ２ A thickness of about 20 g / m is preferable. ２ ~Approx. 500g / m ２are preferred. Specific examples of gas-permeable packaging materials (films or sheets that are entirely or partially gas-permeable) include stretched films (preferably stretched porous films or sheets containing such films). Stretched porous films generally contain inorganic fillers, and gas permeability is achieved by the formation of interconnecting pores through stretching. As described above, the type of gas-permeable material to be used as the gas-permeable packaging material is determined appropriately based on the exothermic composition used, the required heat generation amount, temperature, and heat generation time. Furthermore, when heat sealing is used as a joining method to the first covering part, it is preferable to select the material for the second covering part in relation to the material for the first covering part.

[0058] Furthermore, it is preferable that the second covering portion is flexible, i.e., soft and bendable. During the production of the heat generating element according to this embodiment, the heat generating composition expands after the liquid component is injected. In this case, at least a portion of the second covering portion bulges outward along the shape of the swollen heat generating composition. The flexibility allows this bulging.

[0059] In addition, the gas-permeable packaging material constituting the second covering part preferably has a water-resistant pressure higher than the liquid pressure at the time of pouring the liquid component in. In relation to the liquid pressure at the time of pouring, which will be described later, the water-resistant pressure (liquid pressure resistance) of the gas-permeable packaging material is preferably 0.1 to 100 KPa, more preferably 0.1 to 30 KPa, even more preferably 0.5 to 30 KPa, and most preferably 1 to 30 KPa.

[0060] (2-5. Adhesive Body) The adhesive body according to this embodiment is not particularly limited, and may be not only a so-called solvent type, emulsion type, or hot melt type, but also a gel type (for example, sodium polyacrylate), etc. Specific examples of the adhesive include acrylic adhesives, rubber adhesives, urethane adhesives (acrylic urethane adhesives), silicone adhesives, ethylene-vinyl acetate copolymer adhesives, polyester adhesives, polyamide adhesives, and epoxy adhesives.

[0061] 3. Manufacturing Method of Heating Element A manufacturing method of a heating element according to this embodiment will be described with reference to FIG. 8. FIG. 8 is a diagram showing an example of the flow of an example (S1) of a manufacturing method of a heating element according to this embodiment. Note that S10 to S30 in FIG. 8 correspond to a manufacturing method of a heating element precursor according to this embodiment. As shown in FIG. 8, the manufacturing method S1 of a heating element according to this embodiment includes a manufacturing step S10 of a heat-generating composition precursor, a manufacturing step S20 of a first covering portion, a sealing step S30 of the heat-generating composition precursor, a liquid component injection step S40, and a sealing step S50 of the outer bag. Below, the manufacturing method of a heating element according to this embodiment (S1) will be described separately for each step.

[0062] <3-1. Step S10 for Producing a Heat-Generating Composition Precursor> Step S10 for producing a heat-generating composition precursor is a step of mixing and molding (e.g., compression molding (e.g., tableting)) the components of the heat-generating composition precursor. The components are as described above. The components of the heat-generating composition are divided into solid components (room temperature) and liquid components (room temperature). The former are further divided into non-soluble components (e.g., water-insoluble components; e.g., oxidizable metal powders, activated carbon, swelling agents, temperature control agents, etc.) that are insoluble or poorly soluble in liquid components (e.g., water) and soluble components (e.g., water-soluble components; e.g., salts, pH adjusters, etc.) that are readily soluble in liquid components (e.g., water-soluble components). Of these, step S10 for producing a heat-generating composition precursor involves mixing only non-soluble components (e.g., water-insoluble components), or mixing non-soluble components (e.g., water-insoluble components) with one or more soluble components (e.g., water-soluble components) to produce a heat-generating composition precursor. That is, a suitable heat-generating composition precursor is a mixture of components that are solid at room temperature, consisting of insoluble components (e.g., water-insoluble components), or containing insoluble components (e.g., water-insoluble components) and one or more soluble components (e.g., water-soluble components), and is substantially free of liquid components (e.g., water only, an aqueous solution of some or all water-soluble components, or an aqueous solution containing some or all water-soluble components and components other than water that are liquid at room temperature). Here, "insoluble or poorly soluble" refers to a component that dissolves less than 1 g per 100 g of liquid component at room temperature (25 ° C). On the other hand, "easily soluble" refers to a component that dissolves 1 g or more per 100 g of liquid component at room temperature (25 ° C). Here, using a more specific example, the manufacturing process S10 of the heat-generating composition precursor is explained. As the solid components (insoluble components and soluble components) of the heat-generating composition precursor, iron powder, activated carbon, salt, a water-absorbent polymer as a swelling agent, and crystalline cellulose as a binder are prepared. The solid components are weighed and placed in a polyethylene bag, which is then sealed and mixed together. The resulting mixture is molded (e.g., by pressure molding (e.g., tableting with a tabletop tablet press)) to produce a cylindrical exothermic composition precursor.

[0063] <3-2. First Covering Portion Manufacturing Step S20> First covering portion manufacturing step S20 is a step of manufacturing the first covering portion, which is carried out before, after, or in parallel with exothermic composition precursor manufacturing step S10. It is preferable that first covering portion manufacturing step S20 be carried out before or in parallel with exothermic composition precursor manufacturing step S10 so that the exothermic composition precursor can be sealed in a bag or container immediately after its production. Here, the first covering portion manufacturing step S20 will be explained using a more specific example. A non-air-permeable packaging material (e.g., polyester) is molded (e.g., the non-air-permeable packaging material is sandwiched between a heated convex stainless steel pressing mold and a concave stainless steel receiving mold and pressed), thereby obtaining a first covering portion having a deep storage portion (recess) and a peripheral portion.

[0064] <3-3. Heat-generating Composition Precursor Encapsulation Step S30> The heat-generating composition precursor encapsulation step S30 is a step of producing a heat-generating element precursor by encapsulating the heat-generating composition precursor in a covering. Here, the heat-generating composition precursor encapsulation step S30 will be explained using a more specific example. The heat-generating composition precursor produced in the heat-generating composition precursor encapsulation step S10 is placed (through the opening of the first covering) into the housing of the first covering produced in the first covering production step S20. A second covering (e.g., a breathable polyester nonwoven fabric) is then placed over the first covering. Next, the first covering and the second covering are joined (e.g., by thermocompression bonding; specifically, by applying pressure from the second covering side with a heated stainless steel heat seal bar) to encapsulate the heat-generating composition precursor. The above steps constitute the manufacturing process for the heat-generating element precursor. Note that the manufacturing steps S10 to S30 may also be performed by deep-draw packaging. Specifically, for example, the deep-draw packaging process includes the steps of vacuum-forming (e.g., heated vacuum forming) a bottom material (e.g., roll-shaped) that will be the raw material for the first covering portion to create a recess (receiving portion), pouring a heat-generating composition precursor into the recess, sealing (e.g., vacuum-sealing) a top material (e.g., roll-shaped) that will be the raw material for the second covering portion from above, and cutting. The liquid component injection step S40 described below may be performed before or after the cutting step. The adoption of this deep-draw packaging process stabilizes the molding height, thereby further preventing performance variations between products.

[0065] <3-4. Liquid Component Injection Step S40> The liquid component injection step S40 is a step of injecting a liquid component into the heat-generating composition precursor enclosed in the heat-generating element precursor produced in the heat-generating composition precursor encapsulation step S30. Here, the liquid component injection step S40 will be explained using a more specific example. The liquid component is applied to the second covering portion (the portion covering the opening of the first covering portion) while applying pressure. (For example, the heat-generating element precursor is placed under the nozzle of a plunger pump (with the second covering portion facing up), and a liquid component (e.g., water) is ejected from the nozzle, whereby the liquid component is injected into the heat-generating element precursor by the ejection pressure.) If the first covering portion has an air vent, the liquid component may be injected through the air vent. Upon injection of the liquid component, the liquid component comes into contact with the heat-generating composition precursor, causing the swelling agent contained in the heat-generating composition to swell. As a result, cracks occur in multiple locations in the molded (e.g., pressure-molded (e.g., tableted)) heat-generating composition precursor. The steps described above are the manufacturing process for the heating element.

[0066] 3-5. Encapsulating into outer bag step S50> The enclosing into outer bag step S50 is a step of enclosing the heating element produced in the liquid component injection step S40 in an outer bag. Here, the outer bag is preferably airtight and substantially oxygen-impermeable (for example, transparent alumina-deposited polyester, low-density polyethylene, etc.).

[0067] <3-6. Others> When an adhesive body is provided on the heating body, the method may include a step of attaching the adhesive body to the heating body (for example, using a comma coater, gravure coater, hot melt T-die coater, etc.), and a step of attaching a release body to the adhesive body (or a step of attaching an adhesive body with a release body to the heating body). Furthermore, the second covering part used in the step S30 of enclosing the heat-generating composition precursor may have an adhesive body and a release body on its surface.

[0068] 4. Uses The heat generating element according to the present embodiment can be widely used in medical devices such as hot compresses and heat devices for stimulating meridians, or in daily necessities such as disposable body warmers and moxibustion devices.

[0069] <<Production of Heat-Generating Element>> <Production of Heat-Generating Composition Precursor> The raw materials for the heat-generating composition precursor, which are solid components (water-insoluble and water-soluble components) at room temperature, were iron powder (Powder Tech Co., Ltd. reduced iron powder "RDH-3M"), activated carbon (Dainen Co., Ltd. wood powder activated carbon "PL-1P"), salts (Nihon Kaisui Co., Ltd. powdered salt "EF-300"), a water-absorbent polymer (Sanyo Chemical Co., Ltd. polyacrylic acid resin "ST-500D*") as a swelling agent, crystalline cellulose (Asahi Kasei Chemicals Corporation crystalline cellulose "CEOLUS TG-101") as a binder, and an α-olefin copolymer (Toyokuni Oil Mills Co., Ltd. "HS Crysta-6100P") as a temperature control agent. Here, 45.0 parts by weight of iron powder, 7.0 parts by weight of activated carbon, 3.5 parts by weight of salts, 30.0 parts by weight of crystalline cellulose, 25.0 parts by weight of temperature control agent, and 5.0 parts by weight of water-absorbent polymer were used as the basic formulation. The weighed solid ingredient raw materials were placed in a polyethylene bag, and mixed for 3 minutes with the bag closed and sufficient air allowed to enter. 1.2 g of this mixed raw material was weighed and compressed into tablets using a tablet press (ESTEC Co., Ltd., "Tabletop Rotary Table Press PICCOLA Standard Machine") (tabletting pressure: 10 KN). A pressing die with a diameter of 13.9 mm and a receiving die with an inner diameter of 14 mm was used to produce a cylindrical exothermic composition precursor with a diameter of 14 mm and a thickness of 5 mm.

[0070] <Molding of first covering portion> A nylon / polyethylene film (Kurilon Chemical Co., Ltd., total thickness 180 μm, not measurable, i.e., air permeability >80,000 sec / 100 cc) was sandwiched between a convex stainless steel pressing mold heated to 110°C and a concave stainless steel receiving mold from which cooling air was released, pressed for 4 seconds, and then, 0.5 seconds later, cooled with air for 4 seconds to produce a cup-shaped first covering portion having a storage portion with an inner diameter of 21 mm, an outer diameter of 26 mm, and a height of 7 mm.

[0071] <Encapsulation in the Cover> One heat-generating composition precursor was placed in the first cover prepared above, and a polyester / polyethylene laminated spunbond nonwoven fabric ("HST40" manufactured by Shinwa Co., Ltd., basis weight = 40 g / m) was placed on top of it as the second cover. ２A stainless steel heat seal bar (air permeability = 0.2 sec / 100 cc) was placed over the separator to cover the opening of the first covering part. A stainless steel heat seal bar heated to 180°C was used to apply pressure (10 MPa) from the separator side for 10 seconds, thermocompressing the second covering part and the first covering part together at their peripheries to seal in the heat-generating composition precursor. After sealing, the heat-generating composition precursor was punched out to a diameter of 26 mm with a Thomson blade to produce a heat-generating element precursor.

[0072] <Injection of Liquid Component> The coated body was placed under the water outlet so that the adhesive surface of the coated body was facing up. Water was supplied at a stroke of 4.5 mm using a pump (HIBER "Hiber Pump") with a channel inlet inner diameter of 2 mm and an outlet inner diameter of 0.8 mm. The edge (spout) of a 6 mm diameter silicone buffer member attached to the tip of the metal tube of the water injection head was brought into contact with the adhesive surface side (second coated portion side) (nonwoven fabric surface of the coated body) of the coated body in which the heat-generating composition precursor had been encapsulated, and 0.4 g of water was injected per heat-generating element to produce the heat-generating element.

[0073] <Encapsulation in outer bag> The obtained heating element was immediately enclosed in an outer bag of transparent alumina-deposited polyester 12 μm / low-density polyethylene 40 μm after production, and left to stand at room temperature.

[0074] Example 1 A heating element according to Example 1 was produced by the manufacturing method described above.

[0075] Example 2 A heating element according to Example 2 was produced using the same manufacturing method as Example 1, except that one vent hole (diameter 1.0 mm) was formed in the center of the top surface of the first covering part. Note that water was injected from the second covering part side as described above.

[0076] Example 3 A heating element according to Example 3 was produced using the same manufacturing method as in Example 1, except that one ventilation hole (1.0 mm in diameter) was formed in the center of the top surface of the first covering part, and four adhesive bodies (four adhesive applications of 4 mm in diameter and 1 mm in thickness (glue lumps pressed with an iron)) were formed on the attachment surface of the second covering part (see the second from the left in the top row of Figure 7; 3 mm of the 4 mm in diameter glue was positioned so that it overlapped the opening). Note that water was injected from the second covering part side, as described above.

[0077] (Example 4) The heating element of Example 4 was produced using the same manufacturing method as Example 1, except that an adhesive body with a coating amount of 90 μm and a width of 6 mm was formed in the center of the attachment surface of the second covering portion (see the fifth from the left in the top row of Figure 7).

[0078] Example 5 A heating element according to Example 5 was produced using the same manufacturing method as Example 1, except that two vent holes (1 mm diameter) were formed at equal distances along the diameter of the top surface of the first covering part, and an adhesive body with a coating amount of 90 μm and a width of 6 mm was formed in the center of the attachment surface of the second covering part (see the fifth from the left in the top row of Figure 7). Note that water was injected from the second covering part side, as described above.

[0079] Example 6 The heating element of Example 5 was produced using the same manufacturing method as Example 1, except that one ventilation hole (1 mm in diameter) was formed in the center of the top surface of the first covering part, and an adhesive body (see the fifth from the left in the top row of Figure 7) with a coating amount of 90 μm and a width of 10 mm was formed in the center of the attachment surface of the second covering part. Note that water was injected from the second covering part side as described above.

[0080] (Example 7) One heat-generating composition precursor was placed on an unformed film (special polyolefin sheet "HUMOFIT" manufactured by Mitsui Chemicals, Inc., thickness 500 μm), and a polyester / polyethylene laminated spunbond nonwoven fabric ("HST40" manufactured by Shinwa Co., Ltd., basis weight = 40 g / m) was placed on top of it as a second covering portion. ２ , air permeability = 0.2 sec / 100 cc) was then covered. Pressure (10 MPa) was applied for 5 seconds from the nonwoven fabric side using a stainless steel heat seal bar heated to 180°C, and the second covering portion and the first covering portion were thermocompression bonded at their peripheries to encapsulate the heat-generating composition precursor. After encapsulation, the material was punched out with a Thomson blade to a diameter of 26 mm, producing a heat-generating element precursor. Thereafter, the heat-generating element of Example 7 was produced using the same manufacturing method as in Example 1. Note that water was injected from the second covering portion side as described above.

[0081] (Comparative Example 1) A nonwoven fabric ("Smash Y65230" manufactured by Asahi Kasei Corporation) that is a gas-permeable packaging material is used for the first covering part, and an adhesive material (adhesive body 90 μm / PET spunlace nonwoven fabric 30 g / m) that is a non-gas-permeable packaging material is used for the second covering part. ２A heating element of Comparative Example 1 was produced by the same manufacturing method as in Example 1, except that a thickness of 12 μm PET film and a thickness of 30 μm PE film were used.

[0082] (Comparative Example 2) "InSIP" by Höganäs Japan was used as the iron powder, which is a component of the heat-generating composition precursor, and a nonwoven fabric ("Smash Y65230" by Asahi Kasei Corporation) that is a gas-permeable packaging material was used as the first covering part, and an adhesive material (adhesive body 90 μm / PET spunlace nonwoven fabric 30 g / m) that is a non-gas-permeable packaging material was used as the second covering part. ２ A heating element according to Comparative Example 1 was produced by the same manufacturing method as in Example 1, except that a thickness of 12 μm PET film and a thickness of 30 μm PE film were used.

[0083] <<Heat Generation Test>> The heat generation test was performed in accordance with the JIS S4100 "Disposable Heater" method, with the heater placed horizontally. A tank-shaped heater measuring W615 x D410 x H60 mm (using an 8 mm thick vinyl chloride plate) was used in a thermostatic chamber at room temperature of 20 ° C and humidity of 65%. Hot water was circulated at 8 L / min from a circulating thermostatic water bath attached to the tank-shaped heater, and the surface temperature of the heater (vinyl chloride plate) was controlled at 30 ° C. Each heating element sample was attached to the vinyl chloride plate on the heater surface with the second covering facing down. During attachment, a temperature measurement sensor was attached to approximately the center of the bottom surface of the second covering with double-sided tape, allowing the temperature of the heating element to be measured over time. The temperature measuring device used was a Chino Graphic Recorder KR2S00 manufactured by Chino Graphics Co., Ltd., and the sensor used was an ST-22E-005 manufactured by Anritsu Meter Co., Ltd.

[0084] Here, Table 1 is a table showing various sizes of the heating element precursors according to the examples and comparative examples, and Table 2 is a table showing the volume expansion coefficients of the heating element precursors according to the examples and comparative examples after water was injected into them.

[0085]

[0086]

[0087] The results are shown in Figures 9 to 15 and Table 3. "Rise" was defined as the time from exceeding 31.5°C to exceeding 40°C, and "sustaining time" was defined as the time from reaching 40°C to the next time the temperature reached 40°C.

[0088]

[0089] The heating elements according to Examples 1 to 7 exhibited good heat generation characteristics. That is, it can be seen that the heating elements according to Examples 1 to 7 have a significantly longer duration of heat generation than the heating elements according to Comparative Examples 1 and 2.

[0090] This application is based on Japanese patent application No. 2023-97308 filed on June 13, 2023, and all contents described in the specification and claims of Japanese patent application No. 2023-97308 are incorporated herein by reference.

[0091] REFERENCE SIGNS LIST 10a Heat-generating composition precursor 10b Heat-generating composition 11 Crack 20 Covering body 20a First covering portion 20b Second covering portion 21 Upper surface 22 Lower surface 23 Peripheral portion 24 Storage portion 25 Opening 26 Ventilation area 30 Adhesive body 40 Vent 100 Heat-generating element precursor 200 Heat-generating element

Claims

1. A heat generating composition precursor capable of forming a heat generating composition that generates heat by reacting with oxygen in the air in the presence of a liquid component, the heat generating composition precursor being in the state before the liquid component is added; and a covering body having: a first covering part having a storage section capable of storing the heat generating composition precursor and an opening for storing the heat generating composition precursor, the first covering part being made of an air-impermeable packaging material; and a second covering part covering the opening in a flat shape, the second covering part being made of an air-permeable packaging material.

2. A heat generating composition precursor capable of forming a heat generating composition that generates heat by reacting with oxygen in the air in the presence of a liquid component, the heat generating composition precursor being in the state before the liquid component is added; and a covering body having: a first covering portion having a concave containing portion capable of containing the heat generating composition precursor and an opening for containing the heat generating composition precursor, the first covering portion being made of a non-air permeable packaging material; and a second covering portion covering the opening in a flat shape, the second covering portion being made of a air permeable packaging material.

3. A heat generating composition precursor capable of forming a heat generating composition that generates heat by reacting with oxygen in the air in the presence of a liquid component, the heat generating composition precursor before the liquid component is added; and a covering body having: a first covering part having a first storage part capable of storing the heat generating composition precursor and having a first depth, and an opening for storing the heat generating composition precursor, the first covering part being made of a non-air permeable packaging material; and a second covering part covering the opening, the second storage part having a second depth different from the first depth, and the second covering part being made of a air permeable packaging material.

4. A heat generating composition precursor capable of forming a heat generating composition that generates heat by reacting with oxygen in the air in the presence of a liquid component, the heat generating composition precursor comprising: a heat generating composition precursor before the liquid component is added; a first covering part made of an easily deformable, non-air permeable packaging material; and a second covering part made of an air permeable packaging material; wherein the heat generating composition precursor is contained between the first covering part and the second covering part, with the first covering part being deformed by the heat generating composition precursor.

5. A heating element precursor according to any one of claims 1 to 4, wherein the first covering portion has at least one ventilation hole.

6. A heat generating composition precursor according to any one of claims 1 to 4, comprising a swelling agent capable of absorbing a liquid component, the swelling agent being capable of swelling within the container when it absorbs the liquid component.

7. The heat generating element precursor according to any one of claims 1 to 4, wherein the ratio of the volume of said heat generating composition precursor to the volume of said container is 0.2 or more.

8. A heating element precursor according to any one of claims 1 to 4, wherein air is introduced into the opening through a gap that is generated between the second covering portion and the object to be heated when the second covering portion faces the object to be heated.

9. A heating element precursor according to any one of claims 1 to 4, further comprising an adhesive applied to said second covering portion and overlapping a portion of said opening.

10. A heating element in which the liquid component is introduced into the container of the heating element precursor according to any one of claims 1 to 4 via the second covering portion.

11. The heating element according to claim 10, wherein the heat generating composition precursor is in a molded solid form, and when the liquid component is introduced into the container, the heat generating composition precursor in the solid form becomes the heat generating composition in a cracked form.

12. The heating element according to claim 10, wherein the time during which the heat generation temperature is at or above 40° C. exceeds 20 minutes.

13. The heating element according to claim 10, wherein at least a portion of the second covering portion bulges outward due to swelling of the heat generating composition precursor.

14. A moxibustion device comprising the heating element according to claim 10.

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