JP2024102332A - Warmer - Google Patents

Abstract

To provide a warmer having excellent heat generation characteristics and excellent amount of steam generation.SOLUTION: A warmer includes a heating element 3 containing powder of an oxidizable metal 3a, powder of a carbon material 3b, diatomaceous earth 3c and water. In the heating element, the content of the diatomaceous earth relative to the oxidizable metal is preferably 10 mass% or more and 60 mass% or less, and the basis weight of the diatomaceous earth is preferably 0.002 g/cm2 or more and 0.020 g/cm2 or less. Preferably, the heating element includes a base material sheet, and an exothermic composition 30 provided on one surface of the base material sheet. Further, the heating element is preferably made of a sheet-like material containing powder of an oxidizable metal, powder of a carbon material, diatomaceous earth, water, and a fiber material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heating device.

Heating devices that utilize heat generated by the oxidation reaction of oxidizable metals are used for a variety of purposes. The present applicant previously proposed a heating element and a heating device equipped with the same, which is composed of a heating layer containing an oxidizable metal, a water absorbent, and water, and a water-retaining layer formed from a water-absorbent sheet (see Patent Document 1). The heating element described in this document contains water, so that water vapor is generated as the oxidizable metal undergoes an oxidation reaction.

The applicant also proposed a steam heating mask that covers the user's nose and mouth when in use, has a mask body equipped with a steam generator, and a pair of ear loops on both the left and right ends of the mask body, for the purpose of improving the moist feeling of the mucous membranes of the throat and nose (see Patent Document 2).

US2014/373828 A1 US2018/318166 A1

The present invention relates to a heating device.
In one embodiment, the heating device comprises a heating element including a powder of an oxidizable metal, a powder of a carbon material, diatomaceous earth, and water.
In one embodiment, the heating element has a content ratio of the diatomaceous earth to the oxidizable metal (diatomaceous earth/oxidizable metal) of 10 mass % or more and 60 mass % or less.
Other features of the invention will be apparent from the claims and the following description.

1(a) to (c) are cross-sectional views showing schematic configurations of the heating element in the heating device. FIG. 2 is a schematic diagram of a device for measuring the amount of steam generated from a heating device. 3(a) to 3(c) are cross-sectional views showing schematic arrangements of a heating element and a water-absorbent resin layer in a heating device. FIG. 4 is a cross-sectional view showing a schematic arrangement of a heating element and a water-absorbent resin layer in a heating device. FIG. 5 is a plan view showing a schematic diagram of one embodiment of the heating device. FIG. 6 is an exploded perspective view showing a schematic diagram of the heating device shown in FIG. FIG. 7 is a schematic diagram of a cross section along the lateral direction, which is the longitudinal direction, of the heating device shown in FIG. FIG. 8 is a schematic diagram of an enlarged cross section of the heating device shown in FIG. FIG. 9 is a diagram showing a schematic diagram of the heating device shown in FIG. 5 in use. FIG. 10 is a plan view showing a schematic diagram of another embodiment of the heating device. FIG. 11 is a plan view showing a schematic diagram of a heating device according to still another embodiment. FIG. 12 is a perspective view showing a schematic diagram of a heating device according to still another embodiment.

Detailed Description of the Invention

In recent years, in response to the increasing demand for heating devices, technologies have been considered for inexpensively manufacturing and providing heating devices with enhanced heat generating properties and maintaining or improving quality such as the amount of water vapor generated, etc. One method for improving quality by increasing heat generating properties and increasing the amount of water vapor generated is, for example, to increase the content of oxidizable metals, but in this case, manufacturing costs increase and it is difficult to provide products at low cost.
Furthermore, one method for producing heating devices at low cost is to reduce the content of oxidizable metals, but in this case, the heat generated by the oxidation reaction becomes insufficient, and the heat generating properties deteriorate, resulting in a reduced amount of water vapor generated, and as a result, a high-quality heating device cannot be obtained.

The inventors conducted extensive research into improving heat generating properties and unexpectedly discovered that by using inexpensive and versatile diatomaceous earth, and mixing an oxidizable metal with diatomaceous earth in a specific content ratio, it is possible to manufacture a heating device that has heat generating properties and water vapor generation amounts equal to or greater than conventional heating devices, while still being cheaper than conventional heating devices.
In addition, they discovered that by adjusting the content ratio of oxidizable metal and diatomaceous earth to have a specific relationship, it is possible to manufacture a heating device with excellent heat generation characteristics and water vapor generation rate.

Therefore, the present invention relates to a heating device.
In one embodiment, the heating device has excellent heat generating properties and water vapor generation while keeping production costs down.

The present invention will now be described based on its preferred embodiments.
In the present specification, when an upper limit or lower limit or upper and lower limits of a numerical value are specified, the upper limit and lower limit values themselves are included. Furthermore, even if not specifically stated, it is understood that all numerical values or numerical ranges below the upper limit or above the lower limit, or within the range of the upper and lower limits, are described.
As used herein, "a" and "an" and the like are intended to mean one or more.
In light of the following disclosure in this specification, it is understood that various modifications and alterations of the present invention are possible. Therefore, it should be understood that the present invention can be practiced in embodiments not specifically described in this specification within the technical scope based on the description of the claims.
The contents of the above-mentioned patent documents and each of the patent documents described below are incorporated in their entirety into this specification as part of the content of this specification.

The heating device of the present invention is used in order to apply heat to an object to be heated by contacting the object with the heating device during use.
The object to be heated may be, but is not limited to, the human eyes, mouth, nose and the skin and mucous membranes around them, or the skin and mucous membranes in the throat, face, scalp, neck, arms, shoulders, legs, knees, abdomen, back, waist, buttocks, etc.

The heating device of the present invention may, for example, be in the following forms (a) to (d), but is not limited to these forms.
(a) An eye mask configuration that is configured to be held around the eye.
(b) An attachment form configured to be held on the neck, arm, shoulder, leg, elbow, knee, forehead, abdomen, back or waist.
(c) A face mask configuration that can be held around the mouth, nose, or entire face.
(d) A cup shape configured to be able to contact the mouth, nose and surrounding areas.
The disclosure regarding the heating device in this specification is applicable to all of the above-mentioned aspects (a) to (d).

The heating device of the present invention comprises a heating element.
The heating element preferably contains (1) a powder of an oxidizable metal, (2) a powder of a carbon material, (3) diatomaceous earth, and (4) water.
The oxidizable metal powder has the function of generating heat through an oxidation reaction with oxygen in the air, thereby making it possible to impart heat to an object to be heated.
The powder of the carbon material is used to promote the oxidation reaction of the oxidizable metal and generate heat efficiently.
The diatomaceous earth has a function of increasing the heat generation efficiency by supplying water, which acts as a medium, to the reaction system when the powder of the carbon material promotes the oxidation reaction of the oxidizable metal. The diatomaceous earth is preferably used in the form of a powder.
Water has the function of facilitating the generation of an interaction between the powder of the oxidizable metal and the carbon material or the like that serves as a catalyst for the oxidation reaction.
The heating element preferably comprises a mixture containing the materials (1) to (4) above.

The heating element is preferably configured as a sheet.
A "sheet-like object" is a thin object that has two opposing surfaces, a small thickness between the surfaces, and is flexible and shape-retaining.
The sheet-like material has a thickness of 0.6 mm or more, preferably 0.8 mm or more, and more preferably 1.0 mm or more.
The thickness of the sheet-like material is 3.0 mm or less, preferably 2.8 mm or less, and more preferably 2.0 mm or less.

The heating element constituting the heating device is preferably configured to have the function of reacting with oxygen in the air to generate heat, and generating water vapor heated to a predetermined temperature as a result of this heat generation.
In this case, the water contained in the heating element may partially evaporate into water vapor as heat is generated due to the oxidation reaction of the oxidizable metal.

The heating element may take the following forms (i) to (iii), for example.
One embodiment of the heat generating element is (i) a form in which the heat generating element is a sheet-like object comprising a base sheet and a layer of a heat generating composition provided on one surface of the base sheet.
In this case, the heat generating composition is obtained by applying a paste containing a powder of an oxidizable metal, a powder of a carbon material, diatomaceous earth, and water onto one side of a base sheet.
In the following description, the form of the heating element of (i) above will also be referred to as a "coating type."

Another example of the heating element is (ii) a heating element comprising a heat generating composition including a powder of an oxidizable metal, a powder of a carbon material, diatomaceous earth, and water, and preferably further including a fibrous material, which is then paper-made into a sheet-like product.
In the following description, the heating element of type (ii) above will also be referred to as a "papermaking type."

Further, as still another embodiment of the heating element, there can be mentioned (iii) an embodiment in which the heating element is a powdery material containing a powder of an oxidizable metal, a powder of a carbon material, diatomaceous earth and water.
In the following description, the form of the heating element (iii) is also referred to as a "powder type."

The heating element may be in any of the forms (i) to (iii) as they are.
Alternatively, a heat generating element having any one of the forms (i) to (iii) may be housed in an air-permeable packaging material.
It is also preferable that the packaging material be one that does not allow solids to flow in or out.
When the heating element is contained within a packaging material, the packaging material is separate from the heating element, i.e., the packaging material does not constitute the heating element.

The shape of the packaging material is not particularly limited, but a flat shape is preferable.
When forming the packaging material into a flat shape, it is also preferable that the packaging material is formed by laminating together one side of a first sheet material having breathability and the other side of a second sheet having lower breathability than the first sheet material.

One embodiment of the heating element described above is shown, for example, in Figures 1(a) to (c).
FIG. 1(a) shows an example of a coating type heating element, FIG. 1(b) shows an example of a paper-made type heating element, and FIG. 1(c) shows an example of a powder type heating element.
1(a) to (c), the respective components are shown as a heating element 3, a heating composition 30, a base sheet 31, a powder of an oxidizable metal 3a, a powder of a carbon material 3b, diatomaceous earth 3c, a fibrous material 33, and a packaging material 35.

It is preferable that the heating element constituting the heating device has a predetermined content ratio for at least one of the content ratios of oxidizable metal and diatomaceous earth, and the content ratio of water and diatomaceous earth.

In detail, the ratio of the mass of diatomaceous earth to the mass of the oxidizable metal powder contained in the heating element (diatomaceous earth/oxidizable metal) is preferably 10 mass% or more, more preferably 14 mass% or more, and even more preferably 20 mass% or more.
In addition, the ratio of the mass of diatomaceous earth to the mass of the oxidizable metal powder contained in the heating element (diatomaceous earth/oxidizable metal) is preferably 60 mass% or less, more preferably 50 mass% or less, and even more preferably 40 mass% or less.
By setting the content ratio of the oxidizable metal and the diatomaceous earth as described above, even if the content of the oxidizable metal is less than that of conventional heating devices, it is possible to achieve heat generation characteristics equal to or better than conventional heating devices. In addition, it is possible to reduce the manufacturing cost of the heating device. Furthermore, it is possible to improve the manufacturing efficiency of the heating element and the heating device equipped with the heating element.
In addition, when the content ratio of diatomaceous earth is increased, the heating device may have good heat generating properties and water vapor generation amount, but the mass of the heating device itself may become large, and the feeling of use of the heating device may be insufficient. From the viewpoint of combining the improvement of heat generating properties and water vapor generation amount with the feeling of use of the heating device, it is more preferable to set the ratio of the mass of the diatomaceous earth content to the mass of the oxidizable metal powder contained in the heating element to the more preferable range described above, and it is even more preferable to set it to the further preferable range described above.

Examples of the oxidizable metal powder constituting the heating element include powders of iron, aluminum, zinc, manganese, magnesium, calcium, etc. These may be used alone or in combination of two or more kinds.
Among these, it is preferable to use metallic iron from the viewpoints of ease of handling, safety, and production costs, that is, iron powder is preferably used.
The iron powder may be, for example, one or more types selected from reduced iron powder and atomized iron powder.
The oxidizable metal powder constituting the heating element may be an aggregate of metal particles having no pores on the particle surface, or may be an aggregate of porous metal particles.

The powder of the carbon material constituting the heating element has a function of promoting the oxidation reaction, and specifically, can have one or more functions of an oxygen-holding/supplying material for the oxidizable metal and a catalytic function.
Examples of such carbon materials include activated carbon such as coconut shell charcoal, charcoal powder, bicarbonate coal, peat and lignite, carbon black, acetylene black, graphite powder, etc. These may be used alone or in combination of two or more kinds.
Among these, activated carbon powder is preferably used as the powder of the carbon material because it has a good balance between oxygen supplying ability and catalytic ability.

The diatomaceous earth constituting the heating element is a fossil deposit (sedimentary rock) derived from diatoms, and is preferably used in the form of a powder.
Typically, diatomaceous earth is extracted from a deposit of diatomaceous sedimentary rock, and then dried, crushed, and refined as necessary. Commercially available diatomaceous earth may be used, or the product may be further subjected to calcination, crushing, or washing with an acid.
Diatomaceous earth typically has a large number of pores formed therein, and the pores formed in the diatomaceous earth may be of the open cell type, the closed cell type, or a combination thereof.
In addition, diatomaceous earth is a substance whose main component is SiO _2. In this disclosure, the inventors have confirmed that the effects of the present invention cannot be achieved even if, for example, silica gel, which is a porous SiO ₂ powder, is used instead of diatomaceous earth.

The basis weight of the diatomaceous earth in the heating element is preferably 0.002 g/cm ² or more, more preferably 0.005 g/cm ² or more, and even more preferably 0.009 g/cm ² or more.
The basis weight of the diatomaceous earth in the heating element is preferably 0.020 g/cm ² or less, more preferably 0.018 g/cm ² or less, and even more preferably 0.015 g/cm ² or less.
The basis weight of diatomaceous earth is the mass of diatomaceous earth relative to the area of the heating element in a plan view.
With this configuration, even if the content of the oxidizable metal is reduced, the oxidation reaction of the oxidizable metal can be sufficiently and continuously promoted, resulting in a heating device that exhibits excellent heat generating properties. In addition, the manufacturing cost of the heating device can be reduced.
Increasing the basis weight of the diatomaceous earth may result in a heating device with good heat generation characteristics and water vapor generation, but the mass of the heating device itself may become large, and the feel of the heating device may be insufficient. From the viewpoint of achieving both improved heat generation characteristics and water vapor generation and a good feel of the heating device, it is more preferable to set the basis weight of the diatomaceous earth relative to the mass of the oxidizable metal powder contained in the heating element to the more preferred range described above, and even more preferable to set it to the even more preferred range described above.

It is preferable that the ratio R1 or R2 of the sensible heat integrated amount to the basis weight of the heat generating element is within a predetermined range. The sensible heat integrated amount is a value expressed by the integral of the temperature and the duration of heat generation, and the larger the sensible heat integrated amount, the more excellent the heat generation characteristics.
In detail, the ratio R1 of the accumulated sensible heat (°C/10 min) from the point when the heating device reaches 35°C until 10 minutes later to the basis weight (g/ ^cm2 ) of the heating element is preferably 14,000 or more, more preferably 15,000 or more, and even more preferably 16,000 or more, from the viewpoint of making the heating device have even better heat generation characteristics immediately after use.
In addition, from the viewpoint of generating an appropriate amount of heat immediately after use of the heating device and imparting a comfortable warmth to the heated object such as a user, the ratio R1 is preferably 20,000 or less, more preferably 19,000 or less, and even more preferably 18,000 or less.

In addition, the ratio R2 of the accumulated sensible heat (°C/20 min) from the point when the heating device reaches 35°C until 20 minutes later to the basis weight (g/ ^cm2 ) of the heating element is preferably 26,000 or more, more preferably 27,000 or more, and even more preferably 28,000 or more, from the viewpoint of continuously generating heat and providing a heating device with even superior heat generating properties.
Furthermore, from the viewpoint of continuously exerting the heat generating properties of the heating device and imparting a comfortable feeling of warmth to the heated object, such as a user, the ratio R2 is preferably 40,000 or less, more preferably 35,000 or less, and even more preferably 30,000 or less.

The above-mentioned ratios R1 and R2 can be adjusted to the desired ratios, for example, by appropriately adjusting the mass ratio of water to oxidizable metal in the heating element.

The accumulated amount of sensible heat can be measured, for example, in an environment of room temperature of 20° C. and humidity of 50% RH by the following method.
First, the oxygen barrier bag is opened for the heating device to be measured, which is sealed in the oxygen barrier bag, and one heating element is removed from the heating device. If the heating element is contained in a packaging material, the heating element is removed together with the packaging material.
Next, a temperature sensor is installed and fixed on one side of the heating element. The temperature sensor is fixed to the measurement surface with a mesh material (polyester, double raschel fabric with a thickness of 8 mm) and a SUS plate (500 g perforated plate). When the removed heating element is contained in a packaging material, a temperature sensor is installed and fixed in the area where the heating element is arranged on one side of the packaging material. When the packaging material is composed of a first sheet material and a second sheet material described later, the first sheet material side of the packaging material is arranged to face the outer surface, and a temperature sensor is installed and fixed in the area where the heating element is arranged on the surface of the second sheet material side.
Then, the temperature is measured over time using a measuring device described in JIS S4100 connected to a temperature sensor. The measurement is started when the oxygen barrier bag is opened and the heating element is exposed to the atmosphere, and the temperature is measured at 10 second intervals for a total of 10 minutes or 20 minutes.
From the heat generation profile plotted with the measured temperature (°C) on the vertical axis and the measurement time (seconds) on the horizontal axis, the integral value of the temperature is calculated by subtracting 35°C from the measured temperature at the time when a temperature of 35°C or higher is measured, and this is the accumulated sensible heat (°C·10 min or °C·20 min).
Thereafter, the calculated integrated amount of sensible heat is divided by the basis weight of the heating element to calculate the ratio R1 or the ratio R2.

When the heating element is configured to be capable of generating water vapor, it is preferable that the ratio R5 of the total amount of water vapor (mg/10 min) generated from the start of heat generation of the heating device up to 10 minutes after the start of heat generation to the basis weight (g/ ^cm2 ) of the heating element is within a specified range.
In detail, the ratio R5 is preferably 1,300 or more, more preferably 1,600 or more, and further preferably 1,700 or more.
Moreover, the ratio R5 is preferably 2,500 or less, more preferably 2,200 or less, and further preferably 2,000 or less.
With this configuration, the heater has excellent heat generation characteristics and generates a large amount of water vapor, so that the heated objects such as the eyes, nose, and throat can feel both a comfortable warmth and moisture.

When the heating element is configured to be capable of generating water vapor, the ratio ^R6 of the total amount of water vapor (mg/20 min) generated from the start of heat generation of the heating device up to 20 minutes after the start of heat generation to the basis weight (g/cm2) of the heating element is preferably 2350 or more, more preferably 2500 or more, and even more preferably 2700 or more.
Moreover, the ratio R6 is preferably 4,000 or less, more preferably 3,500 or less, and further preferably 3,000 or less.
With this configuration, the heater has excellent heat generation characteristics and generates a large amount of water vapor, so that the heated objects such as the eyes, nose, and throat can feel both a comfortable warmth and moisture.

The above-mentioned ratios R5 and R6 can be adjusted to the desired ratios, for example, by appropriately adjusting the mass ratio of water to oxidizable metal in the heating element.

The total water vapor amount can be measured, for example, by the following method. In detail, the total water vapor amount can be measured using an apparatus 100 shown in FIG.
First, for the heating device to be measured that is sealed in an oxygen barrier bag, the oxygen barrier bag is opened and one heating element is taken out. If the heating element is contained in a packaging material, the heating element is taken out together with the packaging material.
The packaging material for the removed heating element is placed in the measurement chamber 101 with one side facing outward, and weight 108 with a metal ball (mass 4.5 g) attached is placed on top of it. When the packaging material is composed of a first sheet material and a second sheet material described below, the packaging material for the removed heating element is placed in the measurement chamber 101 with the side of the first sheet material facing outward, and weight 108 with a metal ball (mass 4.5 g) attached is placed on top of it.
In this state, dehumidified air is allowed to flow from the bottom of the measurement chamber 101, and the difference in absolute humidity before and after air circulation in the measurement chamber 101 is calculated from the temperatures and humidities measured by the inlet thermo-hygrometer 104 and outlet thermo-hygrometer 106. Furthermore, the amount of water vapor released from the heating tool is calculated from the air flow rates measured by the inlet flowmeter 105 and outlet flowmeter 107. The total amount of water vapor is calculated from the point in time when the heating tool is removed from the oxygen barrier bag and the heating element is brought into contact with air, with the measurement start point being the total amount measured for 10 minutes (mg·10 min) and the total amount measured for 20 minutes (mg·20 min) from that point in time.
Thereafter, the calculated total amount of water vapor is divided by the basis weight of the heating element to calculate the ratio R5 or the ratio R6.

From the viewpoint of obtaining a heating device with excellent heat generating properties and capable of continuously exhibiting said heat generating properties with high productivity, the pore diameter D1 of the diatomaceous earth is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1.0 μm or more.
The pore diameter D1 of the diatomaceous earth is preferably 10.0 μm or less, more preferably 7.5 μm or less, and even more preferably 5.0 μm or less.
By setting the pore diameter D1 of the diatomaceous earth in this range, the moisture held in the diatomaceous earth powder can be efficiently transferred to the oxidizable metal side, thereby further improving the heat generation characteristics.
The above-mentioned effects become more pronounced by setting the pore diameter D1 within a more preferred range, and become even more pronounced by setting the pore diameter D1 within an even more preferred range.

The pore diameter D1 of the diatomaceous earth described above can be measured, for example, by the mercury intrusion method specified in JIS R 1655 as follows.
Specifically, 0.02 g to 0.1 g of diatomaceous earth powder is used as a measurement sample, a measurement cell containing the measurement sample is set in a mercury porosimeter (Autopore IV9500, manufactured by Micromeritics), and the cumulative pore volume V (cm ³ /g) of the measurement sample is measured as the mercury injection pressure P is increased within a predetermined range. Next, the relationship between the converted pore diameter D (μm) converted according to the following formula (A) is plotted on the horizontal axis and the log differential pore volume (dV/d(log ₁₀ D); cm ³ /g) is plotted on the vertical axis to obtain a pore volume distribution. In other words, the converted pore diameter D is plotted on the horizontal axis and the pore volume obtained by differentiating the cumulative pore volume V with the logarithm of the pore diameter D is plotted on the vertical axis to obtain a pore volume distribution.
D=4γcosθ/P...(A)
(γ: surface tension of mercury, θ: contact angle, P: mercury injection pressure)

The measurement is performed in an environment of 22°C and 65% RH. The surface tension γ of mercury is 480 dyn/cm, the contact angle θ is 140°, and the mercury injection pressure P is in the range of 0 psia (0 MPa) to 60,000 psia (413.685 MPa). Based on the distribution curve of the converted pore diameter D obtained under these measurement conditions, the cumulative total value of the converted pore diameters D in the range of 0.0018 μm to 100 μm is defined as the cumulative pore volume V (mL/g), and the median value of the pore diameters in the distribution curve is defined as the pore diameter D1 (μm) of the present invention.

The oil absorption of the diatomaceous earth is preferably 50 mL/100 g or more, more preferably 75 mL/100 g or more, and even more preferably 100 mL/100 g or more.
The oil absorption of the diatomaceous earth is preferably 300 mL/100 g or less, more preferably 250 mL/100 g or less, and even more preferably 200 mL/100 g or less.
With this configuration, the water contained in the heating element is sufficiently retained in the diatomaceous earth particles, and the water retained in the diatomaceous earth can be transferred more efficiently to the oxidizable metal side, thereby enabling the heating characteristics to be sustained and efficiently improved.

The oil absorption of diatomaceous earth can be measured by the following method. Specifically, 1-5 g of the powder sample to be measured is placed in the center of the measurement plate, and 4-5 drops of boiled linseed oil are dropped from a burette onto the center of the sample, and the whole is thoroughly mixed with a palette knife each time. Dropping of boiled linseed oil and mixing of the sample are repeated, and when the whole sample becomes a hard putty-like mass, one drop of boiled linseed oil is dropped onto the boiled linseed and mixed. The end point is when one drop of oil is dropped onto the boiled linseed and the sample can be rolled into a spiral shape using a palette knife, and the amount of boiled linseed oil dropped (mL) is read from the scale. However, if the sample cannot be rolled into a spiral shape, the end point is when the sample suddenly becomes soft when one drop of oil is dropped onto the boiled linseed, and the amount of boiled linseed oil dropped (mL) is read from the scale.
The amount of powder sample to be used for the measurement is determined in accordance with the provisions of JIS K5010-13-2 after a preliminary test is carried out to confirm the approximate value of the oil absorption amount.
The amount of oil dropped (mL) obtained according to the above-mentioned method is converted into an amount per 100 g of the powder sample to be measured, and the oil absorption amount (mL/100 g) of the present invention is calculated.

From the viewpoint of achieving both continuous generation of water vapor and appropriate progress of the oxidation reaction, it is also preferable to further dispose a water-absorbent resin in or near the heating element.
From the viewpoint of achieving both continuous generation of water vapor and moderate progress of the oxidation reaction, as well as preventing unintended dropping off of constituent materials and further improving production efficiency, when a water-absorbent resin is further disposed, it is further preferable that a packaging material is further disposed and a layer containing water-absorbent resin powder is disposed between the heat-generating composition in the heat generating element and the packaging material.
The above-mentioned respective forms are applicable to any of the coating type, the paper-making type, and the powder type.
By further disposing a water-absorbent resin in or near the heating element, it is possible to absorb excess moisture present in the heating element, which in turn makes it possible to efficiently advance the oxidation reaction of the oxidizable metal and improve the heating properties, while at the same time allowing the moisture held in the water-absorbent resin and the heating element to be continuously released as water vapor, providing the user of the heating device with a comfortable feeling of warmth.

When a water-absorbent resin is further disposed in or near the heating element, one embodiment of the water-absorbent resin is, for example, a form in which the water-absorbent resin powder is mixed with the oxidizable metal and carbon material powders of the heat-generating composition in the heating element, as well as with diatomaceous earth and water. In this case, the water-absorbent resin powder constitutes a part of the heating element.

Alternatively, as another embodiment of the water-absorbent resin, a layer containing a powder of the water-absorbent resin is adjacent to the heat-generating composition in the heat-generating body. In this case, the layer containing the powder of the water-absorbent resin is configured separately from the heat-generating body.
Examples of the embodiment in which a layer containing water-absorbent resin powder is present adjacent to a heat generating element include (a) an embodiment in which a single layer is formed by sandwiching water-absorbent resin powder between two moisture-permeable sheets, (b) an embodiment in which water-absorbent resin powder is arranged in a single layer in contact with the heat generating composition constituting the heat generating element without any other member therebetween, and (c) an embodiment in which a laminated structure in which a first water-absorbent resin layer in which water-absorbent resin powder is arranged adjacent to each other in a layered form and a second water-absorbent resin layer adjacent to the first water-absorbent resin layer and formed by sandwiching water-absorbent resin powder between two moisture-permeable sheets are arranged, is arranged in the heat generating composition constituting the heat generating element without any other member therebetween.
That is, in any of the above-mentioned cases (a) to (c), it is preferable that a heat-generating composition constituting a heat generating element is disposed between the base sheet and the layer containing the water-absorbent resin powder.

Alternatively, as yet another embodiment of the water-absorbent resin, a layer containing a powder of the water-absorbent resin is disposed as a base sheet and is adjacent to the heat-generating composition in the heat-generating element. In this case, the powder of the water-absorbent resin constitutes a part of the heat-generating element.
The layer containing the water-absorbent resin powder is preferably formed by sandwiching the water-absorbent resin between two moisture-permeable sheets. In this case, it is also preferable that the heat-generating composition in the heat generating element is disposed in contact with the outer surface of one of the moisture-permeable sheets.

When a layer containing water-absorbent resin powder is disposed as a base sheet, the layer containing water-absorbent resin powder is preferably contained in a packaging material together with the heating element, from the viewpoint of preventing unintended falling off of the constituent materials.
When a packaging material is provided, it is also preferable that the packaging material is formed by laminating together a first sheet material having breathability on one side and a second sheet having lower breathability than the first sheet material on the other side.
In the case where the layer containing the water-absorbent resin powder is arranged as a base sheet and a packaging material is provided, it is further preferable that the layer containing the water-absorbent resin powder and a first sheet material having breathability in the packaging material are arranged to face each other.

As for the mode of existence of the heat generating element and the water-absorbent resin, one embodiment in which a layer containing a powder of the water-absorbent resin is adjacent to the heat generating element is illustrated in Figs. 3(a) to (c).
In the embodiment shown in Figures 3(a) to (c), a layer 3L containing powder of a water-absorbent resin 37 (hereinafter, also referred to as a water-absorbent resin layer 3L) is disposed between the heat-generating composition 30 and the packaging material 35 in the heat-generating element 3.
Although the heat generating element 3, water-absorbent resin layer 3L, and packaging material 35 shown in Figures 3(a) to (c) are drawn to have different thicknesses overall, this is shown only for convenience of explanation, and the actual heat generating element 3, water-absorbent resin layer 3L, and packaging material 35 in each of the forms shown in Figures 3(a) to (c) may be the same or different in thickness.

In detail, when the water-absorbent resin layer 3L is disposed, as shown in Fig. 3(a), the water-absorbent resin layer 3L is preferably formed by sandwiching a water-absorbent resin 37 between two moisture-permeable sheets 38, 38. In this case, it is also preferable that the water-absorbent resin layer 3L is in contact with the heat-generating composition 30 constituting the heat generating element 3 via the moisture-permeable sheet 38.
In particular, it is preferable that the heat generating composition 30 constituting the heat generating element 3 is disposed between the base sheet 31 and the water-absorbent resin layer 3L.
With this configuration, it is possible to continuously release water vapor while continuously exhibiting excellent heat generating properties, and generate more water vapor than conventional heating devices, so that the heated objects such as the eyes, nose, and throat can be continuously made to feel both a comfortable warmth and moisture.
This configuration of the water-absorbent resin layer is advantageous in that, for example, by applying it to a heating device, preferably in the form of an eye mask or a patch, it can provide the user with a continuous sensation of warmth in the application area, such as the user's eyes and the surrounding area, thereby providing comfort to the user.

Alternatively, as shown in FIG. 3(b), it is also preferable that the water-absorbent resin layer 3L is arranged such that the water-absorbent resin 37 is adjacent to the heat-generating composition 30 constituting the heat generating element 3 without any other member therebetween.
In particular, it is preferable that the heat generating composition 30 constituting the heat generating element 3 is disposed between the base sheet 31 and the water-absorbent resin layer 3L.
This configuration allows the device to generate more water vapor than conventional heating devices, which has the advantage of further increasing the amount of water vapor generated and providing a comfortable sensation of warmth and moisture to the heated objects such as the eyes, nose, mouth, and throat.
This configuration of the water-absorbent resin layer is advantageous in that, for example, by applying it to a heating device, preferably in the form of a face mask, it can provide the user with a widespread sensation of warmth and moisture in and around the mouth and nose, providing comfort to the user.

Alternatively, as shown in FIG. 3( c ), the water-absorbent resin layer 3L preferably has a laminated structure in which a first water-absorbent resin layer 3 s in which a water-absorbent resin 37 is disposed adjacent to the heat-generating composition 30 constituting the heat generating element 3 without any other member therebetween, and a second water-absorbent resin layer 3 t in which the water-absorbent resin 37 is sandwiched between two moisture-permeable sheets 38, 38 adjacent to the first water-absorbent resin layer 3 s are disposed.
In the embodiment shown in FIG. 3(c), the water-absorbent resin layer 3L has a laminated structure in which a first water-absorbent resin layer 3s and a second water-absorbent resin layer 3t are disposed adjacent to each other.
This configuration allows the heat generation reaction of the heating element to proceed efficiently, generating a large amount of water vapor in a relatively short time, allowing the heated objects such as the eyes, nose, mouth, and throat to quickly sense warmth and moisture.
This configuration of the water-absorbent resin layer 3L is advantageous in that, for example, when applied to a heating implement, preferably in the form of a cup, it can provide a concentrated sensation of warmth and moisture to the user's mouth, nose and surrounding areas in a short period of time.

Regarding the mode of existence of the heat generating element and the water-absorbent resin, another embodiment in which a layer containing a powder of the water-absorbent resin is adjacent to the heat generating composition in the heat generating element is illustrated in FIG.
In the embodiment shown in FIG. 4, a water-absorbent resin layer 3L is disposed between the heat generating composition 30 and the packaging material 35 in the heat generating element 3.
As shown in FIG. 4, the water-absorbent resin layer 3L is preferably formed by sandwiching a water-absorbent resin 37 between two moisture-permeable sheets 38, 38.
4, the heat generating composition 30 in the heat generating element 3 is preferably disposed in contact with one surface of a moisture permeable sheet 38. In this case, it is also preferable that the water-absorbent resin layer 3L is used as the base sheet 31 in the heat generating element 3.
As shown in FIG. 4, when the water-absorbent resin layer 3L is arranged as a base sheet 31 and a flat packaging material 35 is provided, it is more preferable that the water-absorbent resin layer 3L and a first sheet material having air permeability in the packaging material are arranged to face each other.
With this configuration, it is possible to continuously release water vapor while continuously exhibiting excellent heat generating properties, and generate more water vapor than conventional heating devices, so that the heated objects such as the eyes, nose, and throat can be continuously made to feel both a comfortable warmth and moisture.
This configuration of the water-absorbent resin layer is advantageous in that, for example, by applying it to a heating device, preferably in the form of an eye mask or a patch, it can provide the user with a continuous sensation of warmth in the application area, such as the user's eyes and the surrounding area, thereby providing comfort to the user.

When the water-absorbent resin layer is disposed adjacent to the heating element, the water-absorbent resin layer is preferably configured as a sheet-like material.

Specific examples of the water-absorbent resin include starch, crosslinked carboxymethylated cellulose, polymers or copolymers of acrylic acid or alkali metal acrylic acid salts, polyacrylic acid and its salts, and polyacrylate graft polymers. As the polyacrylate salt, a sodium salt can be used.
The shape of the water-absorbent resin may be spherical, lumpy, grape-cluster-shaped, fibrous, or particles consisting of a combination thereof.
The water-absorbent resin is preferably a powder consisting of an aggregate of particles.

As the moisture permeable sheet, for example, a fiber sheet such as tissue paper, absorbent paper, or nonwoven fabric, or a mesh sheet, etc. can be used.
The moisture-permeable sheet preferably has breathability.

The heating element preferably has a water content relative to the oxidizable metal powder (water/oxidizable metal) of 30% by mass or more, more preferably 80% by mass or more, and even more preferably 100% by mass or more.
The content ratio of water to the oxidizable metal powder contained in the heating element (water/oxidizable metal) is preferably 200 mass % or less, more preferably 180 mass % or less, and even more preferably 150 mass % or less.
With this configuration, the oxidation reaction of the oxidizable metal can be sufficiently and continuously promoted, resulting in a heating device with excellent heat generating properties. In addition, the manufacturing cost of the heating device can be reduced.

In order to sufficiently and sustainably advance the oxidation reaction of the oxidizable metal and further improve the heat generating properties, the heating element preferably has a diatomaceous earth to water ratio (diatomaceous earth/water) of 5 mass% or more, more preferably 10 mass% or more, and even more preferably 20 mass% or more.
In addition, from the viewpoint of improving the manufacturing efficiency of the heating element, the content ratio of diatomaceous earth to water contained in the heating element (diatomaceous earth/water) is preferably 60 mass % or less, more preferably 50 mass % or less, and even more preferably 40 mass % or less.
This configuration results in excellent heat generating properties and makes the heating device 1 easy to manufacture. In addition, it is possible to reduce the manufacturing cost of the heating device. In particular, by setting the content of diatomaceous earth relative to water within the above-mentioned range, it is advantageous in that when obtaining a coating-type heating element, the viscosity of the heat generating composition paste can be appropriately controlled, thereby improving coating efficiency and therefore manufacturing efficiency.

In the heating element described above, the content ratio of the oxidizable metal to the diatomaceous earth, the content ratio of the oxidizable metal to the water, and the content ratio of the water to the diatomaceous earth may be any one of these that satisfies the suitable content ratio, any two of these that satisfies the suitable content ratio, or all of these that satisfies the suitable content ratio.

In other words, the heating element may only satisfy the preferred content ratio of the oxidizable metal to the diatomaceous earth, or may only satisfy the preferred content ratio of the oxidizable metal to the water, or may only satisfy the preferred content ratio of the water to the diatomaceous earth.
By having any of the above-mentioned configurations, even if the content of oxidizable metal is reduced compared to conventional heating devices, it is possible to exhibit heat generation characteristics that are equal to or better than conventional heating devices.

In addition, the heating element may be one that satisfies both the preferred content ratio of the oxidizable metal to diatomaceous earth and the preferred content ratio of the oxidizable metal to water, or may be one that satisfies both the preferred content ratio of the oxidizable metal to water and the preferred content ratio of water to diatomaceous earth, or may be one that satisfies both the preferred content ratio of the oxidizable metal to diatomaceous earth and the preferred content ratio of water to diatomaceous earth.
By having any combination of the above-mentioned configurations, it is possible to maintain a good balance between oxygen supply ability and catalytic ability, so that even if the content of oxidizable metal is reduced compared to conventional heating devices, even better heat generation characteristics can be achieved.

The heating element may satisfy all of the preferred content ratios of the oxidizable metal and diatomaceous earth, the preferred content ratio of the oxidizable metal and water, and the preferred content ratio of water and diatomaceous earth.
By creating a heating element that satisfies all of these requirements, the balance between oxygen supply ability and catalytic ability can be maintained even better, and the oxidation reaction of the oxidizable metal can be allowed to proceed sufficiently and sustainably. Therefore, even if the content of the oxidizable metal is reduced compared to conventional heating devices, it is possible to efficiently express heat generation characteristics that are equal to or better than those of conventional devices.
In addition, the manufacturing costs of the heating element and the heating device including the heating element can be further reduced.
Furthermore, the manufacturing efficiency of the heating element and the heating device including the heating element can be further improved.

From the viewpoint of obtaining a heating device with good heat generating properties by appropriately controlling the oxidation reaction, the particle size of the particles constituting the oxidizable metal powder is preferably 1 μm or more, and more preferably 10 μm or more.
From the same viewpoint, the particle size of the particles constituting the powder of the oxidizable metal 3a is preferably 200 μm or less, and more preferably 100 μm or less.

From the viewpoint of fully exerting the catalytic ability of the oxidation reaction and obtaining a heating device with good heat generating properties, the particle diameter of the particles constituting the powder of the carbon material is preferably 1 μm or more, and more preferably 10 μm or more.
From the same viewpoint, the particle size of the particles constituting the powder of the carbon material is preferably 200 μm or less, and more preferably 100 μm or less.

From the viewpoint of obtaining a heating device with good heat generating properties by appropriately controlling the retention and supply of water, the particles constituting the diatomaceous earth powder preferably have a particle size of 1 μm or more, more preferably 10 μm or more.
From the same viewpoint, the particle size of the particles constituting the diatomaceous earth powder is preferably 200 μm or less, and more preferably 100 μm or less.

When the water-absorbent resin is used as a powder, the particle size of the particles constituting the powder may be within the range commonly used in this technical field.

The particle size of each of the above-mentioned materials can be, for example, the median diameter measured by a laser diffraction scattering method using a laser diffraction/scattering type particle size distribution measuring device (manufactured by Horiba, Ltd., (model number: LA-950V2)).

When the heating element is a paper-type sheet-like material containing a fibrous material, the fibrous material may be any natural or synthetic fibrous material without any particular restrictions.
Examples of natural fiber materials include plant fibers (cotton, kabak, wood pulp, non-wood pulp, peanut protein fiber, corn protein fiber, soy protein fiber, mannan fiber, rubber fiber, hemp, Manila hemp, sisal hemp, New Zealand hemp, Ramie, coconut, rush, wheat straw, etc.), animal fibers (wool, goat hair, mohair, cashmere, alcapa, angora, camel, vicuna, silk, feathers, down, feathers, alginate fiber, chitin fiber, casein fiber, etc.), and mineral fibers (asbestos, etc.). These fiber materials can be used alone or in combination.
Examples of synthetic fiber materials include semi-synthetic fibers (acetate, triacetate, acetate oxide, promix, chlorinated rubber, rubber hydrochloride, etc.), synthetic polymer fibers (nylon, aramid, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyester such as polyethylene terephthalate, polyacrylonitrile, acrylic, polyethylene, polypropylene, polystyrene, polyurethane, rayon, viscose rayon, cupra, etc.), metal fibers, carbon fibers, glass fibers, etc. These fiber materials can be used alone or in combination.
Of these, from the viewpoint of achieving both uniform dispersion of the oxidizable metal and oxygen permeability by ensuring voids, thereby improving heat generation characteristics, it is preferable to use at least one of wood pulp, cotton, and polyester as the fiber material.

The average fiber length of the fiber material is preferably 0.5 mm or more, and more preferably 2 mm or more.
The average fiber length of the fiber material is preferably 10 mm or less, and more preferably 5 mm or less.
The average fiber length of a fiber material is determined by measuring 50 or more fibers in a fiber material, fixing one end of each fiber to a horizontal board and allowing the fiber to hang down under its own weight, and measuring the fiber length using a clamping ruler, or by clamping the fiber on a microscope slide and measuring the fiber length using a microscope, and taking the arithmetic mean value of the measurement results obtained.

From the viewpoint of facilitating the generation of water vapor accompanying the heat generation of the heating element, it is preferable that the heating element contains an electrolyte.
The electrolyte contained in the heating element may be, for example, one or more of a salt of an alkali metal or alkaline earth metal with phosphoric acid or sulfuric acid, or a chloride or hydroxide of an alkali metal or alkaline earth metal.
Among these, it is preferable to use one or more of tripotassium phosphate, potassium hydroxide, sodium chloride, and potassium chloride as the electrolyte, because they are excellent in chemical stability and production costs.
The electrolyte may be used, for example, in the form of a powder, or may be used as a liquid dissolved or dispersed in a liquid medium such as water.

The heating element may be composed only of an oxidizable metal powder, a carbon material powder, a porous substance powder, water, and, if necessary, a fibrous material, or the heating composition may contain other powders other than the oxidizable metal powder, the carbon material powder, and the porous substance powder in addition to various powders, water, and, if necessary, a fibrous material.
The other powder may be, for example, one or more of the above-mentioned water-absorbent resins and electrolytes.
In order to further improve the heat generation characteristics and the amount of water vapor generated, the content of other powders in the heating element is preferably 20 mass% or less, and more preferably 10 mass% or less, expressed as the total mass ratio relative to all the powders constituting the heating element.
The total mass ratio of the oxidizable metal powder, the carbon material powder and the porous substance powder to the total powder constituting the heating element is preferably 80 mass% or more, and more preferably 90 mass% or more, from the viewpoint of further improving the heat generation characteristics and the amount of water vapor generated.
When a water-absorbent resin is contained as another powder, the mass is based on the mass in an absolutely dry state.

A heating device having the above-mentioned configuration further contains diatomaceous earth in the heating element, and by appropriately setting the content ratio of oxidizable metal to diatomaceous earth, it is possible to promote the oxidation reaction of the oxidizable metal.As a result, a heating device with excellent heat generation characteristics and a high accumulated sensible heat amount, which is expressed as the integral of temperature and heat generation duration, can be obtained.
Furthermore, even if the content of oxidizable metals is reduced compared to conventional heating devices, excellent heat generation properties can be exhibited, so that heating devices with heat generation properties equal to or better than conventional heating devices can be manufactured at reduced costs.
Furthermore, when the heating element is formed to be capable of generating water vapor, the amount of water vapor generated can be increased to be equal to or greater than that of conventional devices even if the content of oxidizable metal is reduced, so that a comfortable sense of warmth and moisture can be simultaneously felt on the heated object such as the eyes, nose, throat, etc. In addition, regardless of the form of the heating device, the heating device has excellent heat generation characteristics and water vapor generation while keeping manufacturing costs down.

In general, the oxidation reaction of an oxidizable metal can be affected by the amount of moisture and oxygen present around the metal powder.
In detail, if there is an excessively large amount of moisture around the metal powder, the moisture acts as a barrier making it difficult for the oxidizable metal to come into contact with oxygen, and as a result, the oxidation reaction will not continue or will start slowly.
On the other hand, if the amount of moisture around the metal powder is excessively small, the oxidizable metal will be more likely to come into contact with oxygen, but water-mediated interaction with carbon materials, etc., which act as catalysts for the oxidation reaction, will be less likely to occur. As a result, the oxidation reaction will not be sustained sufficiently, making it difficult to achieve the desired heat generation characteristics.

In this regard, it is presumed that by incorporating diatomaceous earth into the heating element, sufficient water can be retained in the pores of the diatomaceous earth, and the water retained in the diatomaceous earth can be continuously supplied in appropriate amounts to the oxidizable metal, thereby ensuring the amounts of moisture and oxygen necessary for the sustained progression of the oxidation reaction.
In particular, as the oxidation reaction progresses, holes are formed on the surface of the oxidizable metal, making it porous, and the capillary force generated between the diatomaceous earth and the oxidizable metal allows water to be continuously supplied from the diatomaceous earth to the oxidizable metal, so that the oxidation reaction progresses continuously, the heat generation amount is sustained for a long period of time, and the heating device has even superior heat generation characteristics.
In addition, due to the enhanced heat generation characteristics, the water contained in the heating element evaporates as heat is generated, and more water vapor is generated than with conventional heating devices, which has the advantage of increasing the amount of water vapor generated and allowing the user of the heating device to experience a comfortable warmth that lasts.

The heating device preferably comprises a main body and a heating element provided in the main body.
It is also preferable that the main body has a shape that covers the object to be heated when in use.
The heating implement preferably comprises a top sheet located on the side closer to the object to be heated, and a back sheet located on the side farther from the object to be heated.
In particular, the heating implement preferably comprises a top sheet positioned closer to the user's skin, and a back sheet positioned farther from the user's skin.
It is preferable that the main body of the heating implement is constituted by the top sheet and the back sheet.
The heating element is preferably held between the top sheet and the back sheet that constitute the main body.
It is also preferable that the heating element is held between the top sheet and the back sheet in a state where it is contained in a breathable packaging material.
When the packaging material is formed of a first sheet material and a second sheet material, the breathable first sheet material is preferably arranged on the side closer to the heating object, more specifically, on the side closer to the user's skin. In other words, the first sheet material is preferably arranged so as to face the top sheet.
When the packaging material is formed of a first sheet material and a second sheet material, the second sheet material, which has lower breathability than the first sheet material, is preferably arranged on the side farther from the heating object, more specifically, on the side farther from the user's skin. In other words, the second sheet material is preferably arranged so as to face the back sheet.
It is also preferable that the heating device is adapted to generate steam heated to a predetermined temperature, thereby making it possible to apply heat to the heating object and its surroundings.

Hereinafter, one embodiment of the heating device will be described with reference to the drawings.
5 to 8 show a heating device having a shape of a so-called eye mask as one embodiment of the heating device. In other words, the present disclosure includes the use of the heating device as an eye mask and a method of using the heating device as an eye mask.
In the following description, components different from the above-described embodiments will be mainly described, and similar components will be denoted by the same reference numerals and description thereof will be omitted. For components not specifically described in this embodiment, the above-described description of each configuration will be applied as appropriate.

The heating device of this embodiment is configured to be held on and around the eyes. The heating device shown in Fig. 5 is used to apply heat to the eyes and their surroundings by placing it over both eyes of a human being, which is the object to be heated, during use.
The heating device is designed to generate steam heated to a predetermined temperature, thereby making it possible to apply heat to the eye and its surroundings, which are the objects to be heated.

As shown in FIG. 5, the heating device 1 of this embodiment preferably comprises a main body 2 that is elongated in the horizontal direction X and has a shape that covers both eyes of the user when in use, and a heating element 3 provided in the main body 2.
It is also preferable that the heating implement of this embodiment is provided with a pair of ear hooks attached to the main body, which make it possible to maintain a state in which both eyes of the user are covered.
In the following description of this embodiment, the direction corresponding to the longitudinal direction of the heating implement is also referred to as the horizontal direction, and the direction perpendicular to the horizontal direction is also referred to as the vertical direction.
The heating device in this embodiment is illustrated in FIG. 5 as a heating device 1, a main body 2, a heat generating element 3, a horizontal direction X, and a vertical direction Y.

In the heating device 1 shown in Fig. 5, the ear hooks 4 are provided on both outer end regions of the main body 2 in the lateral direction X, and can be turned around outward in the lateral direction X. This allows the ear hooks 4, 4 to be hooked around the user's ears, respectively, to maintain the main body 2 covering both of the user's eyes.
From the viewpoint of improving the wearing comfort, it is preferable that the sheet material constituting the ear hook portion 4 is a stretchable sheet.

FIG. 6 shows an exploded perspective view of the heating device 1 of this embodiment.
FIG. 7 shows a cross-sectional view of the heating device 1 taken along the lateral direction X.
The main body 2 of the heating device 1 shown in Figures 6 and 7 is flat and includes a top sheet 5 located closer to the user's skin and a back sheet 6 located further away from the user's skin.

The top sheet 5 constitutes a surface including the areas that come into contact with objects to be heated, such as the human eyes, mouth, and nose, when the heating device 1 is in use.
The back sheet 6 is the surface away from the user's skin and forms the outer surface of the heating device 1. That is, in Figures 6 and 7, the upper side of the paper is the side closer to the user's skin, and the lower side of the paper is the side farther from the user's skin.

The top sheet 5 and the back sheet 6 shown in Figures 6 and 7 are overlapped and bonded to each other with an adhesive 7 such as a hot melt adhesive, so that two heating elements 3, 3 are housed between the two sheets 5, 6 and spaced apart from each other in the horizontal direction X.
That is, in this embodiment, the heating element 3 is configured to be undetachable from the main body 2 .
Of the top sheet 5 and the back sheet 6, at least the top sheet 5 is preferably made of a breathable fiber sheet.
The fiber sheet is an assembly of constituent fibers that are held in a sheet-like shape by at least one of entanglement, fusion, and adhesion.
A detailed description of each of the sheets 5 and 6 will be given later.

The cross-sectional view of FIG. 7 shows the heating element 3 in a fixed state.
As shown in FIG. 7, the heating element 3 is preferably formed by bonding a plurality of sheet materials together by heat sealing or the like, and is housed in a packaging material 35 having air permeability.
The heating element 3 is preferably held between a top sheet 5 and a back sheet 6 that constitute the main body 2 .
In this case, it is also preferable that the heating element 3 is held between the top sheet 5 and the back sheet 6 in a state where it is contained in a breathable packaging material 35 .

It is preferable that the packaging material 35 is flat. In this case, it is also preferable that the packaging material 35 is formed by laminating together a first sheet material having air permeability on one side and a second sheet having lower air permeability than the first sheet material on the other side.
When the packaging material 35 is formed of a first sheet material and a second sheet material, the first sheet material having breathability is preferably disposed on the side closest to the user's skin. In other words, the first sheet material is preferably disposed so as to face the top sheet 5.
When the packaging material 35 is formed of a first sheet material and a second sheet material, the second sheet material, which has lower breathability than the first sheet material, is preferably disposed on the side farther from the user's skin. In other words, the second sheet material is preferably disposed so as to face the back sheet 6.

When the heating device 1 is configured to include a packaging material 35, as shown in Figure 7, it is preferable that the outer surface of the packaging material 35 and the inner surface of the back sheet 6 in the heating device 1 are fixed by adhesive fixing parts 7a, 7a formed by adhesive 7, and that the other surfaces are not fixed to the back sheet 6.
In the embodiment shown in FIG. 7, each adhesive fixing portion 7 a, 7 a is provided in the central region in the lateral direction X of the heating device 1 and extends along the longitudinal direction Y of the heating device 1 .
With this configuration, the heating element 3 can be placed with a high degree of fit to the object to be heated when the heating device 1 is in use, and heat can be efficiently applied to the object to be heated.

Returning to FIG. 6, as shown in the figure, the ear hook portion 4 is preferably made of a sheet material, and an insertion portion 4A extending in the lateral direction X is preferably formed in the sheet material.
The insertion portion 4A is a hole through which the ear is passed when the ear hook portion 4 is hung on the ear.
Alternatively, the insertion portion 4A may be formed by a through slit or the like through which the ear can pass.
As shown in Figures 6 and 8, the ear hook portion 4 is joined to the outer surface of the top sheet 5 of the main body portion 2 at both outer end regions in the horizontal direction X, thereby forming a joining region 9 where the main body portion 2 and the ear hook portion 4 are joined.
The joint region 9 also functions as a folding portion when the ear hook portion 4 is turned over, with the joint end portion 9s as an axis.

FIG. 8 is a cross-sectional view showing the shape of the joint area 9 in the heating device 1 of this embodiment.
The joint region 9 between the main body 2 and the ear hook portion 4 shown in Figures 6 and 8 is preferably continuously joined from a joint end 9s, which is the inner end of the joint region 9 in the horizontal direction X, to the outer end of the main body 2 in the horizontal direction X, and has an approximately semi-elliptical shape.
As shown in FIG. 8, the joining region 9 is preferably formed by joining the topsheet 5 of the main body 2 and the ear hooking portion 4 together.
It is preferable that the joint region 9 also functions as a folding portion when the ear hook portion 4 is turned over, with the joint end portion 9s as an axis.
Although the bonded region 9 shown in FIGS. 6 and 8 is formed by continuous bonding, it may be formed by intermittent bonding instead.

The heating device 1 in the form of an eye mask shown in Figs. 5 to 8 can be used by utilizing the ear hooks 4 to hold the heating device 1 on the ears, as shown in Fig. 9, for example.
By using the heating device in this way, the steam and heat generated from the heating device can be applied uniformly to the user's eyes and the surrounding area regardless of the user's position (e.g., lying on one's back, sitting, etc.). This is advantageous in that it improves the versatility of the heating device's usage.

Another embodiment of the heating device 1 will be described below with reference to Fig. 10. Fig. 10 shows a heating device 1 having a so-called adhesive form as one embodiment of the heating device.
In other words, the present disclosure encompasses the use of the heating device as an adhesive form, as well as a method of using the heating device as an adhesive form.
In the following description, components different from the above-described embodiments will be mainly described, and similar components will be denoted by the same reference numerals and description thereof will be omitted. For components not specifically described in this embodiment, the above-described description of each configuration will be applied as appropriate.

FIG. 10 shows an embodiment in which the heating device 1 is in a patch form.
The heating device 1 of this embodiment preferably comprises a main body 2 having a top sheet 5 which forms the skin-facing surface when in use and a back sheet 6 which forms the non-skin-facing surface when in use, and a heating element 3 provided in the main body 2.
The heating element 3 is preferably held between a top sheet 5 and a back sheet 6 that constitute the main body 2 .
It is also preferable that the heating element 3 is held between the top sheet 5 and the back sheet 6 that constitute the main body 2 while being contained in a breathable packaging material 35 .

In this embodiment, the top sheet 5 constituting the skin-facing surface preferably has an adhesive portion 51 provided over a partial region or the entire region of its outer surface.
The adhesive portion 51 is for holding the heating device 1 to the area where the heat and steam generated from the heating device 1 are to be applied.
By providing the adhesive portion 51, the heating implement 1 can be attached directly to the user's skin or attached to the user's clothing, making it easy to hold the heating implement 1 in a desired position.
In order to allow the adhesive portion to exhibit adhesiveness at a desired timing, a substrate such as a film that covers the adhesive portion may be provided.

Hereinafter, still another embodiment of the heating device 1 will be described with reference to Fig. 11. Fig. 11 shows a heating device 1 having the form of a so-called face mask as one embodiment of the heating device.
Thus, the present disclosure encompasses the use of a heating device as a face mask, as well as a method of using a heating device as a face mask.
In the following description, the components different from the above-described embodiments will be mainly described, and the same components will be denoted by the same reference numerals and will not be described. For components not specifically described in this embodiment, the above-described description of each component will be applied as appropriate.

FIG. 11 shows an embodiment in which the heating device 1 is in the form of a face mask.
The heating device 1 of this embodiment preferably comprises a main body 2 that covers the mouth and nose of the user during use, and a heating element 3 provided in the main body 2.
In addition, the heating device 1 of this embodiment preferably has a pair of ear hooks 4 provided on both the left and right ends of the main body 2. The ear hooks make it possible to maintain a state in which at least one of the user's mouth and nose is covered.
The ear hook portion 4 in this embodiment is made of a sheet material.
It is preferable that an insertion portion 4A is formed in the central region of the ear hook portion 4.
The heating element 3 is preferably held between a top sheet 5 and a back sheet 6 that constitute the main body 2 .
It is also preferable that the heating element 3 is held between the top sheet 5 and the back sheet 6 that constitute the main body 2 while being contained in a breathable packaging material 35 .

As shown in FIG. 10, the heating device 1 of this embodiment preferably has a folding line 15 at a position corresponding to the bridge of the user's nose.
The folding line 15 in this embodiment is provided in the lateral central region of the main body 2 of the heating device 1.
With this configuration, when the heating device 1 in the form of a face mask is used, the folding line 15 acts as a flexible axis and the top sheet 5 can be fitted closely along the convex shape of the nose, reducing the likelihood of gaps occurring between the heating device 1 and the object to be heated, thereby enhancing the heating and humidifying effect.
Alternatively, the heating device 1 may be flat and not have folding lines 15 depending on the application.
The heating device 1 of this embodiment can be used by utilizing the ear hook portion 4 to hold the heating device 1 on the ear.

Hereinafter, still another embodiment of the heating device 1 will be described with reference to Fig. 12. Fig. 12 shows a heating device 1 having a so-called cup shape as one embodiment of the heating device.
That is, the present disclosure encompasses the use of the heating device in the form of a cup, as well as a method of using the heating device in the form of a cup.
In the following description, the components different from the above-described embodiments will be mainly described, and the same components will be denoted by the same reference numerals and will not be described. For components not specifically described in this embodiment, the above-described description of each component will be applied as appropriate.

FIG. 12 shows an embodiment in which the heating device 1 is in the form of a cup.
The heating device 1 of this embodiment preferably comprises a main body 2 that covers at least one of the mouth and nose of the user during use, and a heating element 3 provided in the main body 2.
The heating implement 1 of this embodiment may or may not have ear hooks 4 depending on the application.

The heating device 1 in this embodiment preferably has a main body 2 formed by continuing a first panel portion 21 and a second panel portion 22 having the same shape as the first panel portion 21, as shown in Figure 12.
In this embodiment, both panel portions 21, 22 are formed in a fan shape, and it is preferable that the tapered portions of both panel portions 21, 22 are configured to be continuous.
Both the first panel portion 21 and the second panel portion 22 are composed of a continuous top sheet 5 and a continuous back sheet 6, and it is preferable that the heating element 3 is held between the top sheet 5 and the back sheet 6.
It is also preferable that the heating element 3 is held between the top sheet 5 and the back sheet 6 that constitute the main body 2 while being contained in a breathable packaging material 35 .

The heating device 1 in this embodiment preferably has a boundary line D at the connecting portion between the first panel portion 21 and the second panel portion 22, which serves as a flexible axis along which the main body portion 2 is folded.
In this embodiment, it is preferable that the first panel portion 21 and the second panel portion 22 have a shape that is line symmetrical with respect to the boundary line D.
In the heating device 1 of this embodiment, the surface sheets 5 are folded so as to face each other around the boundary line D, and the first side edge 21A of the first panel portion 21 and the first side edge 22A of the second panel portion 22, as well as the second side edge 21B of the first panel portion 21 and the second side edge 22B of the second panel portion 22 are overlapped and joined.
In both panels 21, 22, the third side edge 21C of the first panel 21 and the third side edge 22C of the second panel 22 located on the outside are not joined together to form an opening in the cup shape. This opening is preferably open enough to cover the nose and mouth of the user.
This forms a cylindrical cup-shaped heating device with a bottom, with the boundary line D and its adjacent position as the bottom. The outer surface of this cup-shaped heating device is formed by the back sheet 6, and the inner surface is formed by the top sheet 5.

The cup-shaped heating device of this embodiment does not have an ear hook. In this case, it is preferable that the cup-shaped heating device with a bottomed cylindrical shape has a body part with dimensions that can be held by hand. In other words, it is preferable that the cup-shaped heating device has a body part that can be held by hand.
When using the cup-shaped heating device, for example, the main body can be grasped by hand and the opening of the cup-shaped heating device can be held near the user's nose and mouth.

The various sheet materials that can be used for the ear loops, the top sheet and the back sheet, as well as the base sheet, the packaging material and the moisture-permeable sheet can each be independently selected as appropriate taking into consideration their properties such as breathability, moisture permeability, texture, elasticity, strength, and prevention of leakage of the constituent materials of the heat-generating composition.
As the sheet material, for example, a fiber sheet such as a nonwoven fabric, a woven fabric, or paper, a resin foam sheet, a metal sheet, or a combination of these may be used.
The sheet material may be a single-layer structure made of only one sheet material, whether single-layer or multi-layer, or may be a laminated structure made of two or more kinds of sheet materials superimposed on each other.

As a sheet material having high air permeability, moisture permeability, and moisture vapor permeability, a meltblown nonwoven fabric is preferably used.
As the sheet material used for the purpose of improving the texture, an air-through nonwoven fabric or a thermal bond nonwoven fabric is preferably used.
Examples of sheet materials used for the purpose of exhibiting elasticity include air-through nonwoven fabrics, spunbond nonwoven fabrics, and thermal bond nonwoven fabrics, which contain synthetic fibers such as polyesters such as polyethylene terephthalate, polyethylene, and polypropylene.
As the sheet material used for the purpose of imparting strength, a spunbond nonwoven fabric, a spunlace nonwoven fabric, a needle punch nonwoven fabric, a chemical bond nonwoven fabric, or the like is suitably used.
In addition to or instead of the nonwoven fabric described above, a nonwoven fabric that has been surface-treated with silicone, a surfactant, or the like can be used, or a foamed sheet made from a thermoplastic resin such as polyethylene or polyurethane can be used.
In addition, these sheet materials can be made by mixing multiple fibers having different fiber raw materials, fiber diameters, degrees of crimp, etc., or by combining multiple sheet materials, so as to achieve desired properties.
The ear hook portion, the top sheet and the back sheet, as well as the base sheet, the packaging material and the moisture-permeable sheet may each independently be a single structure consisting of only one sheet material, whether single-layer or multi-layer, or may be a laminated structure consisting of two or more types of sheet materials layered on top of each other.

When a fiber sheet such as a nonwoven fabric is used as the top sheet and the back sheet, it is preferable that both the top sheet and the back sheet have air permeability. "Having air permeability" means that the air permeability measured according to JIS P8117:2009 is 10000 seconds/100 mL or less. The air permeability measured according to JIS P8117 is defined as the time it takes for 100 mL of air to pass through an area of 6.42 ^cm2 under an environment of 25°C and 0.1013 MPa.
In detail, the air permeability of the top sheet and the back sheet is preferably 0.01 sec/100 mL or more, and more preferably 0.03 sec/100 mL or more, each independently.
The air permeability is measured in accordance with JIS P8117: 2009. A small air permeability means that it does not take long for air to pass through, and therefore means that the breathability is high.
By using a surface sheet with such breathability, it is possible to efficiently apply heat and water vapor to the object to be heated, and to efficiently control the oxidation reaction of the oxidizable metal, thereby obtaining a heating device with the desired heat generation characteristics.

When a packaging material is provided that is breathable and that has a first sheet material that is breathable and a second sheet material that is less breathable than the first sheet material, the breathability of the first sheet material that constitutes the packaging material is preferably 20 sec/100 mL or more, more preferably 30 sec/100 mL or more, and even more preferably 40 sec/100 mL or more.
The air permeability of the first sheet material is preferably 25,000 sec/100 mL or less, more preferably 15,000 sec/100 mL or less, and even more preferably 10,000 sec/100 mL or less.

The first sheet material having the above-mentioned breathability can be, for example, a resin film having a plurality of through holes, or a film obtained by uniaxially or biaxially stretching a sheet obtained from a resin composition containing polyethylene and a filler such as calcium carbonate. The breathability can be appropriately changed by adjusting the degree of stretching.
A sheet which can be applied to the first sheet material is disclosed, for example, in EP 1 939 240 A1.

When a breathable packaging material is provided and the packaging material has a first sheet material that is breathable and a second sheet material that is less breathable than the first sheet material, the breathability of the second sheet material that constitutes the packaging material is preferably 10,000 sec/100 mL or more, and more preferably 25,000 sec/100 mL or more, and it is even more preferable that the second sheet material be non-breathable from the viewpoint of expressing sufficient and appropriate heat generating characteristics and sufficiently applying water vapor to the heated object.
"Non-air permeable" means that the air permeability measured in accordance with JIS P8117:2009 is 80,000 seconds/100 mL or more.
As the second sheet material having the above-mentioned breathability, for example, a resin film having fewer through holes than the first sheet material or having no through holes can be used.

When a breathable packaging material is provided and the packaging material has a first sheet material having breathability and a second sheet material having lower breathability than the first sheet material, the moisture permeability of the first sheet material measured in accordance with JIS Z0208 is preferably 480 g/( ^m2 ·24 h) or more, more preferably 720 g/( ^m2 ·24 h) or more, and even more preferably 960 g/( ^m2 ·24 h) or more.
The moisture permeability of the first sheet material measured in accordance with JIS Z0208 is preferably 5000 g/( ^m2 ·24 h) or less, more preferably 4750 g/( ^m2 ·24 h) or less, and even more preferably 4500 g/( ^m2 ·24 h) or less.
The moisture permeability of the second sheet material measured in accordance with JIS Z0208 is preferably 480 g/(m ² ·24 h) or less, more preferably 240 g/(m ² ·24 h) or less, and even more preferably 0 g/(m ² ·24 h).
By independently setting the moisture permeability of each of the first sheet material and the second sheet material to the above-mentioned ranges, it is possible to exhibit sufficient and appropriate heat generation characteristics and to sufficiently apply water vapor to the object to be heated.
As each sheet material that satisfies such moisture permeability, for example, the same sheet materials as explained above regarding the air permeability can be used.

When a fiber sheet is used as the topsheet, the basis weight of the topsheet is preferably 10 g/m ² or more, more preferably 30 g/m ² or more, and even more preferably 50 g/m ² or more.
The surface sheet has a basis weight of preferably 200 g/ ^m2 or less, more preferably 130 g/ ^m2 or less, and even more preferably 100 g/ ^m2 or more.

Furthermore, when a fiber sheet is used as the back sheet, the basis weight of the back sheet is preferably smaller than that of the top sheet from the viewpoints of improving heat retention and printability.
In particular, the basis weight of the back sheet is preferably 10 g/m ² or more, and more preferably 20 g/m ² or more.
The basis weight of the back sheet is preferably 100 g/m ² or less, more preferably 80 g/m ² or less.
When the top sheet 5 and the back sheet 6 have a laminated structure, the basis weight of the entire sheet may be within the above-mentioned range.

The "moisture permeability" of a moisture permeable sheet means that the moisture permeability of the sheet measured in accordance with JIS Z0208 is 2000 g/(m ² ·24 h) or more.
Specifically, the moisture permeability of the moisture permeable sheet, measured in accordance with JIS Z0208, is preferably 2000 g/( ^m2 ·24 h) or more, more preferably 2500 g/( ^m2 ·24 h) or more, and even more preferably 3000 g/( ^m2 ·24 h) or more.
The moisture-permeable sheet described above can be suitably used as the moisture-permeable sheet in the water-absorbent resin layer. When a plurality of moisture-permeable sheets are used, the moisture permeability values of the respective moisture-permeable sheets may be the same or different.

When the heating implement 1 has ear hooks 4, the shape of the ear hooks 4 is not limited to the sheet-like member shown in Figs. 5 and 6, so long as the main body 2 can be fixed to both eyes of the user.
For example, instead of the ear hook portion 4 made of a sheet material, an ear hook portion 4 made of a string-like material or an ear hook portion 4 made of a thread-like or strip-like material may be used.
In order to improve the fit of the heating implement, it is preferable to use an elastic material such as rubber to make the ear hooks 4 stretchable.

The shape of the heating element 3 in the heating device 1 of the embodiment shown in Figures 5, 10, 11, and 12 has been described as two heating elements 3 held at a distance, but the shape of the heating element 3 is not particularly limited as long as it is possible to impart a sense of warmth to the heated object and its surroundings. For example, one heating element having a shape and size capable of covering the heated object and its surroundings may be held between the top sheet 5 and the back sheet 6, or three or more heating elements may be held between the top sheet 5 and the back sheet 6.

Further, the heating element 3 shown in Figs. 6 and 7 is only partially fixed in the central region of the heating device 1, but the present invention is not limited to this configuration.
For example, the heating element 3 and the back sheet 6 may be joined continuously or intermittently with an adhesive in the central region in the horizontal direction X and in regions other than the central region, or the heating element 3 and the back sheet 6 may be joined by applying an adhesive to the entire surface of the position where the heating element 3 is located on the back sheet 6.

The present invention has been described above based on a preferred embodiment, but the present invention is not limited to the above embodiment.

In addition to the above-described embodiment of the present invention, the following heating device is disclosed.

＜1＞
A heating element including a powder of an oxidizable metal, a powder of a carbon material, diatomaceous earth, and water is provided;
A heating device in which the heating element has a content ratio of the diatomaceous earth to the oxidizable metal (diatomaceous earth/oxidizable metal) of 10% by mass or more and 60% by mass or less.
＜2＞
The heating device described in <1>, wherein the content ratio of the diatomaceous earth to the oxidizable metal in the heating element (diatomaceous earth/oxidizable metal) is preferably 10 mass% or more, more preferably 14 mass% or more, and even more preferably 20 mass% or more.
＜3＞
The heating device described in <1> or <2>, wherein the content ratio of the diatomaceous earth to the oxidizable metal in the heating element (diatomaceous earth/oxidizable metal) is preferably 60 mass% or less, more preferably 50 mass% or less, and even more preferably 40 mass% or less.

＜4＞
The heating device according to any one of <1> to <3>, wherein the basis weight of the diatomaceous earth in the heating element is 0.002 g/cm ² or more and 0.020 g/cm ² or less.
＜5＞
The heating device according to any one of <1> to <4>, wherein the basis weight of the diatomaceous earth in the heating element is preferably 0.002 g/ ^cm2 or more, more preferably 0.005 g/ ^cm2 or more, and even more preferably 0.009 g/ ^cm2 or more.
＜6＞
The heating device according to any one of <1> to <5>, wherein the basis weight of the diatomaceous earth in the heating element is preferably 0.020 g/ ^cm2 or less, more preferably 0.018 g/ ^cm2 or less, and even more preferably 0.015 g/ ^cm2 or less.

＜７＞
The heating device according to any one of <1> to ^<6> , wherein the ratio of the sensible heat accumulated amount (°C/10 min) from the time when the heating device reaches 35°C until 10 minutes later to the basis weight (g/cm2) of the heating element is 14,000 or more and 20,000 or less.
＜8＞
The heating device described in any one of <1> to ^<7> above, wherein the ratio of the accumulated sensible heat (°C/10 min) from the time when the heating device reaches 35°C until 10 minutes later to the basis weight (g/cm2) of the heating element is preferably 14,000 or more, more preferably 15,000 or more, and even more preferably 16,000 or more.
＜9＞
The heating device described in any one of <1> to ^<8> above, wherein the ratio of the accumulated sensible heat (°C/10 min) from the time when the heating device reaches 35°C until 10 minutes later to the basis weight (g/cm2) of the heating element is preferably 20,000 or less, more preferably 19,000 or less, and even more preferably 18,000 or less.
＜10＞
The heating device described in any one of <1> to <9>, wherein the ratio of the sensible heat accumulation (°C/20 min) from the time the heating device reaches 35°C until 20 minutes later to the basis weight (g/ ^cm2 ) of the heating element is 26,000 or more and 40,000 or less.
<11>
The heating device described in any one of <1> to <10> above, wherein the ratio of the accumulated sensible heat (°C/20 min) from the time the heating device reaches 35°C until 20 minutes later to the basis weight (g/ ^cm2 ) of the heating element is preferably 26,000 or more, more preferably 27,000 or more, and even more preferably 28,000 or more.
＜12＞
The heating device described in any one of <1> to <11> above, wherein the ratio of the accumulated sensible heat (°C/20 min) from the time the heating device reaches 35°C until 20 minutes later to the basis weight (g/ ^cm2 ) of the heating element is preferably 40,000 or less, more preferably 35,000 or less, and even more preferably 30,000 or less.

＜13＞
The heating device according to any one of <1> to <12> above, which has a function of generating water vapor when heated.
＜14＞
The heating implement according to <13> above, wherein the ratio of the total amount of water vapor (mg·10 min) generated from the start of heat generation of the heating implement until 10 minutes later to the basis weight (g/cm ² ) of the heating element is 1,300 or more and 2,500 or less.
＜15＞
The heating device described in <13> or <14> above, wherein the ratio of the total amount of water vapor (mg/10 min) generated from the start of heat generation of the heating device until 10 minutes later to the basis weight (g/ ^cm2 ) of the heating element is preferably 1300 or more, more preferably 1600 or more, and even more preferably 1700 or more.
＜16＞
The heating device described in any one of <13> to ^<15> above, wherein the ratio of the total amount of water vapor (mg/10 min) generated from the start of heat generation of the heating device until 10 minutes later to the basis weight (g/cm2) of the heating element is preferably 2500 or less, more preferably 2200 or less, and even more preferably 2000 or less.

＜１７＞
The heating device according to any one of <13> to ^<16> , wherein the ratio of the total amount of water vapor (mg/20 min) generated from the start of heat generation of the heating device until 20 minutes later to the basis weight (g/cm 2 ) of the heating element is 2350 or more and 4000 or less.
＜18＞
The heating device described in any one of <13> to ^<17> above, wherein the ratio of the total amount of water vapor (mg/20 min) generated from the start of heat generation of the heating device until 20 minutes after to the basis weight (g/cm2) of the heating element is preferably 2350 or more, more preferably 2500 or more, and even more preferably 2700 or more.
＜19＞
The heating device described in any one of <13> to ^<18> above, wherein the ratio of the total amount of water vapor (mg/20 min) generated from the start of heat generation of the heating device until 20 minutes later to the basis weight (g/cm2) of the heating element is preferably 4000 or less, more preferably 3500 or less, and even more preferably 3000 or less.

＜20＞
The pore diameter of the diatomaceous earth is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1.0 μm or more.
The heating device according to any one of <1> to <19>, wherein the pore diameter of the diatomaceous earth is preferably 10.0 μm or less, more preferably 7.5 μm or less, and even more preferably 5.0 μm or less.
＜21＞
The heating device according to any one of <1> to <20>, wherein the oil absorption of the diatomaceous earth measured in accordance with JIS K5010-13-2 is preferably 50 mL/100 g or more, more preferably 75 mL/100 g or more, and even more preferably 100 mL/100 g or more.
＜22＞
The heating device according to any one of <1> to <21>, wherein the oil absorption of the diatomaceous earth measured in accordance with JIS K5010-13-2 is preferably 300 mL/100 g or less, more preferably 250 mL/100 g or less, and even more preferably 200 mL/100 g or less.

＜23＞
The heating device according to any one of <1> to <22>, wherein in the heating element, the content ratio of the water to the powder of the oxidizable metal (water/oxidizable metal) is preferably 30% by mass or more, more preferably 80% by mass or more, and even more preferably 100% by mass or more.
＜24＞
The heating device according to any one of <1> to <23>, wherein in the heating element, the content ratio of the water to the powder of the oxidizable metal (water/oxidizable metal) is preferably 200% by mass or less, more preferably 180% by mass or less, and even more preferably 150% by mass or less.
＜25＞
The heating device according to any one of <1> to <24>, wherein in the heating element, the content ratio of the diatomaceous earth to the water (diatomaceous earth/water) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more.
＜26＞
The heating device according to any one of <1> to <25>, wherein in the heating element, the content ratio of the diatomaceous earth to the water (diatomaceous earth/water) is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less.

＜27＞
The heating element is contained in a gas-permeable packaging material,
The heating device according to any one of <1> to <26>, wherein a layer containing water-absorbent resin powder is disposed between the heating element and the packaging material.
＜28＞
The heating device according to <27> above, wherein the water-absorbent resin powder is sandwiched between two moisture-permeable sheets to form the layer.
＜29＞
The layer containing the water-absorbent resin powder is a laminated structure including a first water-absorbent resin layer in which the water-absorbent resin powder is arranged in a layered form, and a second water-absorbent resin layer adjacent to the first water-absorbent resin layer and formed by sandwiching the water-absorbent resin powder between two moisture-permeable sheets.
＜30＞
The moisture permeability of the moisture permeable sheets measured according to JIS Z0208 is preferably 2000 g/( ^m2 ·24 h) or more, more preferably 2500 g/( ^m2 ·24 h) or more, and even more preferably 3000 g/( ^m2 ·24 h) or more. The heating device according to <28> or <29>.
＜31＞
The heating device according to <27>, wherein the water-absorbent resin powder is in contact with the heating element without any other member therebetween to form a single layer.
＜32＞
It is preferable that one surface of the packaging material is constituted by a first sheet material having air permeability,
The heating implement according to any one of <27> to <31>, wherein the other surface of the packaging material is preferably made of a second sheet material having lower breathability than the first sheet material.
＜33＞
The heating implement according to <32>, further preferably, the layer containing the water-absorbent resin powder and the first sheet material of the packaging material are disposed so as to face each other.

＜34＞
The heating element includes a base sheet and a heating composition provided on one surface of the base sheet,
The heating device according to any one of <1> to <33>, wherein the heat generating composition is obtained from a paste containing the oxidizable metal powder, the carbon material powder, the diatomaceous earth, and water.
＜35＞
The heat generating element comprises a base sheet and a layer of a heat generating composition provided on one surface of the base sheet,
the layer of heat generating composition is obtained from a paste containing a powder of the oxidizable metal, a powder of the carbon material, a powder of the porous substance, and water;
Further comprising a layer containing a water-absorbent resin powder,
The heating device according to any one of <1> to <34>, wherein the heat-generating composition is disposed between the base sheet and the layer containing the water-absorbent resin powder.
＜36＞
The heat generating element comprises a base sheet and a layer of a heat generating composition provided on one surface of the base sheet,
the layer of heat generating composition is obtained from a paste containing a powder of the oxidizable metal, a powder of the carbon material, a powder of the porous substance, and water;
Further comprising a layer containing a water-absorbent resin powder,
The heating device according to any one of <1> to <35>, wherein a layer containing the water-absorbent resin powder is disposed as the base sheet.

＜３７＞
The heating device according to any one of <1> to <33>, wherein the heating element is a sheet-like material containing the oxidizable metal powder, the carbon material powder, the diatomaceous earth, water and a fibrous material.
＜３８＞
The heating implement according to <37>, wherein the fiber material preferably contains at least one of wood pulp, cotton, and polyester.
＜３９＞
The oxidizable metal powder is preferably iron powder,
The heating device according to any one of <1> to <38>, further preferably comprising one or more kinds selected from reduced iron powder and atomized iron powder.
＜40＞
The particle size of the particles constituting the powder of the oxidizable metal is preferably 1 μm or more, and more preferably 10 μm or more;
The heating device according to any one of <1> to <39>, wherein the particle size of the particles constituting the powder of the oxidizable metal is preferably 200 μm or less, more preferably 100 μm or less.

＜41＞
The heating device according to any one of <1> to <40>, wherein activated carbon powder is preferably used as the carbon material powder.
＜42＞
The particle size of the particles constituting the powder of the carbon material is preferably 1 μm or more, more preferably 10 μm or more,
The heating device according to any one of <1> to <41>, wherein the particle size of the particles constituting the powder of the carbon material is preferably 200 μm or less, more preferably 100 μm or less.
＜43＞
The particle size of the particles constituting the diatomaceous earth powder is preferably 1 μm or more, more preferably 10 μm or more;
The heating device according to any one of <1> to <42>, wherein the particle size of the particles constituting the powder of diatomaceous earth is preferably 200 μm or less, more preferably 100 μm or less.
＜44＞
The heating device according to any one of <1> to <43>, wherein the heat generating element preferably contains an electrolyte.

＜45＞
The heating element includes a main body having a shape that covers a heating target when in use, and the heating element is provided in the main body,
The main body includes a top sheet located on a side closer to the object to be heated and a back sheet located on a side farther from the object to be heated,
The heating device according to any one of <1> to <44>, wherein the heating element is held between the top sheet and the back sheet.
＜46＞
The device comprises a main body having a shape that covers both eyes of a user when in use, the heating element provided in the main body, and a pair of ear hooks that are attached to the main body and can maintain a state in which both eyes of the user are covered by the main body,
The main body portion includes a top sheet located on a side closer to the user's skin and a back sheet located on a side farther from the user's skin,
The heating device according to any one of <1> to <45>, wherein the heating element is held between the top sheet and the back sheet.
＜47＞
The heating implement according to <45>, wherein the top sheet preferably has an adhesive portion provided on a partial area or the entire area of its outer surface.
＜48＞
A body portion having a shape that covers at least one of a user's mouth and nose when in use, and the heating element provided in the body portion,
The main body portion includes a top sheet located on a side closer to the user's skin and a back sheet located on a side farther from the user's skin,
The heating device according to any one of <1> to <45>, wherein the heating element is held between the top sheet and the back sheet.

＜49＞
The heating device described in <48> further comprises a pair of ear hooks that are attached to the main body and can maintain a state in which the main body covers at least one of the user's mouth and nose.
＜50＞
The headset does not include a pair of ear hooks that are attached to the main body and can maintain a state in which the main body covers at least one of the mouth and nose of the user,
The heating implement according to <48>, wherein the main body is configured to be grippable by hand when the heating implement is in use.

＜51＞
The air permeability of the top sheet measured in accordance with JIS P8117 is preferably 0.01 sec/100 mL or more, and more preferably 0.03 sec/100 mL or more.
The heating implement according to any one of <45> to <50>, wherein the air permeability of the back sheet measured in accordance with JIS P8117 is preferably 0.01 sec/100 mL or more, and more preferably 0.03 sec/100 mL or more.
＜52＞
The surface sheet has a basis weight of preferably 10 g/ ^m2 or more, more preferably 30 g/ ^m2 or more, and even more preferably 50 g/ ^m2 or more.
The heating implement according to any one of <45> to <51>, wherein the basis weight of the surface sheet is preferably 200 g/ ^m2 or less, more preferably 130 g/ ^m2 or less, and even more preferably 100 g/ ^m2 or more.
＜53＞
The basis weight of the back sheet is preferably smaller than the basis weight of the top sheet,
The back sheet has a basis weight of preferably 10 g/ ^m2 or more, more preferably 20 g/ ^m2 or more,
The heating implement according to any one of <45> to <52>, wherein the basis weight of the back sheet is preferably 1 g/ ^m2 or less, and more preferably 80 g/ ^m2 or less.

＜54＞
The heating device according to any one of <45> to <53>, wherein the heating element is preferably held between the top sheet and the back sheet in a state where it is contained in a breathable packaging material.
＜５５＞
It is preferable that one surface of the packaging material is constituted by a first sheet material having air permeability,
It is preferable that the other surface of the packaging material is formed of a second sheet material having lower air permeability than the first sheet material,
It is preferable that the first sheet material is disposed so as to face the top sheet,
The heating device according to <54>, wherein the second sheet material is preferably arranged so as to face the back sheet.

＜５６＞
The heating device described in any one of <32>, <33> and <55> above, wherein the air permeability of the first sheet material measured in accordance with JIS P8117 is preferably 20 sec/100 mL or more, more preferably 30 sec/100 mL or more, and even more preferably 40 sec/100 mL or more.
＜５７＞
The heating device according to any one of <32>, <33>, <55> and <56>, wherein the air permeability of the first sheet material measured in accordance with JIS P8117 is preferably 25,000 sec/100 mL or less, more preferably 15,000 sec/100 mL or less, and even more preferably 10,000 sec/100 mL or less.
＜58＞
The second sheet material preferably has an air permeability of 10,000 sec/100 mL or more, more preferably 25,000 sec/100 mL or more, and further preferably is non-air permeable, as measured in accordance with JIS P8117. The heating device according to any one of <32>, <33>, and <55> to <57>.

＜５９＞
The heating device according to any one of <32>, <33>, and <55> to <58>, wherein the moisture permeability of the first sheet material measured in accordance with JIS Z0208 is preferably 480 g/( ^m2 ·24 h) or more, more preferably 720 g/( ^m2 ·24 h) or more, and even more preferably 960 g/( ^m2 ·24 h) or more.
＜60＞
The heating device according to any one of <32>, <33>, and <55> to <59>, wherein the moisture permeability of the first sheet material measured in accordance with JIS Z0208 is preferably 5000 g/( ^m2 ·24 h) or less, more preferably 4750 g/( ^m2 ·24 h) or less, and even more preferably 4500 g/( ^m2 ·24 h) or less.
＜61＞
The heating device according to any one of <32>, <33>, ^and <55> to <60>, wherein the moisture permeability of the second sheet material measured in accordance with JIS Z0208 is preferably 480 g/( ^m2 ·24h) or less, more preferably 240 g/(m2·24h) or less, and even more preferably 0 g/( ^m2 ·24h).

＜62＞
The heating device according to any one of <1> to <61>, which is in the form of an eye mask.
＜63＞
The heating device according to any one of <1> to <61>, which is in the form of a patch.
＜64＞
The heating device according to any one of <1> to <61>, which is in the form of a face mask.
＜65＞
The heating implement according to any one of <1> to <61>, which is in the form of a cup.

The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to these examples. In the table, blank spaces indicate "non-containing."

[Examples 1 to 6 and Comparative Examples 1 to 4]
<Preparation of Paint>
Iron powder (RKH3, manufactured by DOWA IP Creation Co., Ltd., particle size: 45 μm) was used as the powder of the oxidizable metal, activated carbon powder (Carborafine, manufactured by Osaka Gas Chemicals Co., Ltd., particle size: 31 μm) was used as the powder of the carbon material, and diatomaceous earth powder (Fujifilm Wako Pure Chemical Industries, Ltd., particle size: 20 μm, pore diameter D1: 4.0 μm) was used as the diatomaceous earth. These raw materials were mixed with water, an electrolyte, and a thickener in the ratios shown in Table 1 below to obtain a paste of a heat-generating composition having a viscosity of 5000 mPa·s at 25° C. as measured with a B-type viscometer.

<Preparation of Heating Element>
Particles of water-absorbent resin (AQUALIC (registered trademark) CA, manufactured by Nippon Shokubai Co., Ltd.) were spread in a layer with a basis weight of 50 g/ ^m2 on a wood pulp paper (basis weight 20 g/ ^m2 , manufactured by Ino Paper Co., Ltd.) as a first moisture-permeable sheet. On the layer of water-absorbent resin, a wood pulp paper (basis weight 30 g/ ^m2 , manufactured by Ino Paper Co., Ltd.) was laminated as a second moisture-permeable sheet to obtain a sheet of water-absorbent resin layer.
A polyethylene-laminated thin paper (manufactured by Nittoku Co., Ltd.) was used as a base sheet, and the above-mentioned paste was applied to one side of the sheet by a die coating method while adjusting the discharge pressure to obtain a sheet-like coated product. The discharge pressure was adjusted so that the basis weight of the paste was the value shown in Table 1.
Then, 0.064 g of salt (Otsuka Pharmaceutical Co., Ltd., official sodium chloride) was uniformly spread on the paste side, and then a water-absorbent resin sheet was laminated on the paste side to obtain a laminate precursor. The obtained laminate precursor was then cut to a size of 49 mm x 49 mm to obtain a laminate in which a water-absorbent resin layer was disposed on the heat-generating composition side of the coating-type heat generating element.
Next, the laminate was sandwiched between a breathable first sheet material (breathability: 1500 sec/100 mL) and a non-breathable second sheet material, each cut to 63 mm x 63 mm, and the four sides of these sheets were heat-sealed to obtain a heating element contained in a packaging material. This configuration is exemplified in Fig. 3(a).
The first sheet material in the packaging material was disposed so that its inner surface faced the outer surface of the water-absorbent resin layer sheet, and the second sheet material in the packaging material was disposed so that its inner surface faced the surface of the base sheet.
Finally, the heating element contained in the packaging material was held between a top sheet made of needle-punched nonwoven fabric (basis weight 80 g/ ^m2 ) and a back sheet made of air-through nonwoven fabric (basis weight 30 g/ ^m2 ) by bonding them together to obtain an eye mask-type heating device having the structure illustrated in Figures 5 to 8.
The top sheet was arranged so that its inner surface faced the outer surface of the first sheet material in the packaging material. The back sheet was arranged so that its inner surface faced the outer surface of the second sheet material in the packaging material. This heating device was formed to generate steam when heated.

In addition, in Comparative Example 4, the viscosity of the heat-generating composition paste was very high, and it was not possible to apply it to the base sheet. Therefore, no further measurements were performed.

[Measurement of sensible heat accumulation ratio R1 and ratio R2 per basis weight]
For the heating devices of the examples and comparative examples, the sensible heat accumulated amount for 10 or 20 minutes was measured by the method described above. Then, the ratio R1 of the 10-minute sensible heat accumulated amount (°C·10 min) to the basis weight (g/ ^m2 ) of the heating element, and the ratio R2 of the 20-minute sensible heat accumulated amount (°C·20 min) to the basis weight (g/ ^m2 ) of the heating element were measured.
The higher the ratio R1 and the ratio R2 are, the more excellent the heat generation characteristics are. The results are shown in Table 1 below.

[Measurement of ratios R5 and R6 of total water vapor amount per basis weight]
For the heating devices of the Examples and Comparative Examples, the total amount of water vapor for 10 or 20 minutes was measured using the method described above. Then, the ratio R5 of the 10-minute total amount of water vapor (mg· ¹⁰ min) to the basis weight (g/ ^cm2 ) of the heating element, and the ratio R6 of the 20-minute total amount of water vapor (mg·20 min) to the basis weight (g/cm2) of the heating element were measured and calculated.
The higher the values of the ratios R5 and R6, the more excellent the heat generation characteristics are, and the higher the amount of water vapor generated is, indicating that the heating device is capable of providing a comfortable sensation of warmth and moisture to the heated object. The results are shown in Table 1 below.

As shown in Table 1, the heating devices of the Examples contain diatomaceous earth and have a heating element with a specific content ratio between oxidizable metal and diatomaceous earth, and therefore have a higher sensible heat accumulation and better heating characteristics than the heating devices of the Comparative Examples. It is also clear that this results in a significantly higher amount of water vapor generation.
Therefore, it is evident that the heating device of the present disclosure is capable of producing a heating device with excellent heat generating properties at reduced production costs without increasing the content of costly oxidizable metals.

This provides a heating device that has excellent heat generation properties and water vapor generation while keeping manufacturing costs down.

Claims (14)

A heating element including a powder of an oxidizable metal, a powder of a carbon material, diatomaceous earth, and water is provided;
A heating device in which the heating element has a content ratio of the diatomaceous earth to the oxidizable metal (diatomaceous earth/oxidizable metal) of 10% by mass or more and 60% by mass or less. The heating device according to claim 1, wherein the basis weight of the diatomaceous earth in the heating element is 0.002 g/ ^cm2 or more and 0.020 g/ ^cm2 or less. The heating device according to claim 1 or 2, wherein the ratio of the sensible heat accumulation (°C·10 min) from the time when the heating device reaches 35°C until 10 minutes later to the basis weight (g/ ^cm2 ) of the heating element is 14,000 or more and 20,000 or less. The heating implement according to any one of claims 1 to 3, wherein the ratio of the sensible heat accumulation (°C/20 min) from the time the heating implement reaches 35°C until 20 minutes later to the basis weight (g/ ^cm2 ) of the heating element is 26,000 or more and 40,000 or less. The heating device according to any one of claims 1 to 4, which has the function of generating water vapor in response to heat generation. The heating implement according to claim 5, wherein the ratio of the total amount of water vapor (mg·10 min) generated from the start of heat generation of the heating implement until 10 minutes later to the basis weight (g/cm ² ) of the heating element is 1,300 or more and 2,500 or less. The heating device according to claim 5 or 6, wherein the ratio of the total amount of water vapor (mg·20 min) generated from the start of heat generation of the heating device until 20 minutes later to the basis weight (g/cm ² ) of the heating element is 2350 or more and 4000 or less. The heating element is contained in a gas-permeable packaging material,
The heating device according to any one of claims 1 to 7, wherein a layer containing water-absorbent resin powder is disposed between the heating element and the packaging material. The heating device according to claim 8, wherein the water-absorbent resin powder is sandwiched between two moisture-permeable sheets to form the layer. The heating element includes a base sheet and a heating composition provided on one surface of the base sheet,
The heating device according to any one of claims 1 to 9, wherein the heat generating composition is obtained from a paste containing the oxidizable metal powder, the carbon material powder, the diatomaceous earth and water. The heating device according to any one of claims 1 to 9, wherein the heating element is a sheet-like material containing the oxidizable metal powder, the carbon material powder, the diatomaceous earth, water, and a fiber material. The heat generating element comprises a base sheet and a layer of a heat generating composition provided on one surface of the base sheet,
the layer of heat generating composition is obtained from a paste containing a powder of the oxidizable metal, a powder of the carbon material, a powder of a porous substance, and water;
Further comprising a layer containing a water-absorbent resin powder,
The heating device according to any one of claims 1 to 10, wherein the heat-generating composition is disposed between the base sheet and the layer containing the water-absorbent resin powder. The device comprises a main body having a shape that covers both eyes of a user when in use, the heating element provided in the main body, and a pair of ear hooks that are attached to the main body and can maintain a state in which both eyes of the user are covered by the main body,
The main body portion includes a top sheet located on a side closer to the user's skin and a back sheet located on a side farther from the user's skin,
The heating device according to any one of claims 1 to 12, wherein the heat generating element is held between the top sheet and the back sheet. The heating device according to any one of claims 1 to 13, in the form of an eye mask.

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