Heating devices

Abstract

To provide a warmer having excellent heat generation characteristics and steam generation amount while suppressing a manufacturing cost.SOLUTION: A warmer 1 includes a heating element 3 comprising powder of an oxidizable metal 3a, powder of a carbon material 3b, and powder of a porous substance 3c excluding the oxidizable metal 3a and the carbon material 3b. The heating element 3 is a sheet-like material. It is preferable for the heating element 3 that a value obtained by multiplying a content mass ratio of water to the oxidizable metal 3a by 100 is 30 or more and 270 or less, a value obtained by multiplying a content mass ratio of the porous substance 3a to the oxidizable metal 3c by 100 is 1 or more and 25 or less, and a value obtained by multiplying a content mass ratio of the porous substance 3c to water by 100 is 1 or more and 30 or less. Preferably, a pore diameter of the porous substance 3c is 0.01 μm or more and 5 μm or less. Preferably, an oil absorption amount of the powder of the porous substance 3c is 300 mL / 100 g or more and 900 mL / 100 g or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heating device.

Background Art

[0002] Heating devices that utilize heat generation by the oxidation reaction of oxidizable metals are used in various applications. For example, the applicant has previously proposed a powder-type heating element provided with a heat generation layer containing an oxidizable metal, a water absorbent, and water, and an eye heating device provided with the same (see Patent Document 1). Since the heating element described in this document contains water, water vapor is generated along with the oxidation reaction of the oxidizable metal.

[0003] Also, the applicant has proposed a heating element in which a heat generation layer containing an oxidizable metal, a water absorbent, and water, and a water retention layer formed from a water absorbent sheet are laminated, and a heating device provided with the same (see Patent Document 2). Since the heating element described in this document contains water, water vapor is generated along with the oxidation reaction of the oxidizable metal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] The present invention relates to a heating device. In one embodiment, a heating element is provided that includes a powder of an oxidizable metal, a powder of a carbon material, water, and a powder of a porous material excluding the oxidizable metal and the carbon material. In one embodiment, the heating element is a sheet-like material. In one embodiment, a value [100×(water / content of powder of oxidizable metal)] obtained by multiplying the ratio of the content mass of water to the content mass of the powder of the oxidizable metal by 100 is 30 or more and 270 or less.

[0006] The present invention also relates to another heating device. In one embodiment, the heating element comprises powder of an oxidizable metal, powder of a carbon material, water, and powder of a porous material excluding the oxidizable metal and the carbon material. In one embodiment, the heating element is a sheet-like material. In one embodiment, the heating element has a value obtained by multiplying the ratio of the content mass of the porous material powder to the content mass of the oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] which is between 1 and 25.

[0007] Furthermore, the present invention relates to yet another heating device. In one embodiment, the heating element comprises powder of an oxidizable metal, powder of a carbon material, water, and powder of a porous material excluding the oxidizable metal and the carbon material. In one embodiment, the heating element is a sheet-like material. In one embodiment, the heating element has a value [100 × (porous material powder / water)] which is the ratio of the mass content of the porous material powder to the mass content of the water multiplied by 100, and is between 1 and 30. Other features of the present invention will become apparent from the claims and the following description. [Brief explanation of the drawing]

[0008] [Figure 1] Figures 1(a) and 1(b) are schematic cross-sectional views illustrating the configuration of a heating element in a heating device. [Figure 2] Figures 2(a) to (c) are schematic cross-sectional views showing the arrangement of the heating element and the water-absorbing resin layer in a heating device. [Figure 3] Figure 3 is a schematic cross-sectional view showing another arrangement of the heating element and the water-absorbent resin layer in a heating device. [Figure 4] Figure 4 is a schematic plan view showing one embodiment of a heating device. [Figure 5] Figure 5 is an exploded perspective view schematically showing the heating device shown in Figure 4. [Figure 6] Figure 6 is a schematic diagram of a cross-section along the transverse direction, which is the longitudinal direction of the heating device shown in Figure 4. [Figure 7] Figure 7 is a schematic diagram of an enlarged cross-section of the heating device shown in Figure 5. [Figure 8] Figure 8 is a schematic diagram illustrating the usage of the heating device shown in Figure 4. [Figure 9] Figure 9 is a schematic plan view showing another embodiment of the heating device. [Figure 10] Figure 10 is a schematic plan view showing yet another embodiment of the heating device. [Figure 11] Figure 11 is a schematic perspective view showing yet another embodiment of the heating device. [Figure 12] Figure 12 is a schematic diagram of a device for measuring the amount of steam generated from a heating device. Detailed description of the invention

[0009] In recent years, in response to the growing demand for heating devices, technologies such as improving heating characteristics and increasing steam generation are being explored. One method to improve the heating properties is to increase the content of oxidizable metals, but this would increase manufacturing costs and the mass of the heating device. Furthermore, the powder-type heating element disclosed in Patent Document 1 sometimes has uneven distribution of its constituent materials, such as oxidizable metals, during use, leaving room for improvement in terms of heating characteristics and water vapor generation. Furthermore, the heating element disclosed in Patent Document 2 is in sheet form and has improved heating characteristics, but further improvements in heating characteristics and water vapor generation amount are desired while reducing manufacturing costs.

[0010] The inventors diligently investigated ways to improve the heat generation characteristics and water vapor generation rate, and unexpectedly discovered that by further incorporating porous materials other than oxidizable metals and carbon materials, it is possible to manufacture a heating device with good heat generation characteristics and water vapor generation rate while suppressing manufacturing costs. In addition, we found that by configuring one or more of the following to have a specific relationship: the ratio of oxidizable metal to water, the ratio of oxidizable metal to porous material, and the ratio of oxidizable metal to porous material, it is possible to suppress manufacturing costs while promoting the oxidation reaction of the oxidizable metal, thereby producing a heating device with excellent heat generation characteristics and water vapor generation.

[0011] Therefore, the present invention relates to a heating device. In one embodiment, the heating device exhibits excellent heat generation characteristics and water vapor generation while keeping manufacturing costs down.

[0012] The present invention will be described below based on its preferred embodiments. Where upper or lower limits or upper and lower limits are specified in this specification, the values ​​of the upper and lower limits themselves are also included. Furthermore, even without explicit mention, it shall be interpreted that all numerical values ​​or ranges of numerical values ​​that are less than or equal to the upper limit, greater than or equal to the lower limit, or within the range of the upper and lower limits are included. In this specification, "a" and "an," etc., are to be interpreted as having one or more meanings. In light of the following disclosures herein, it will be understood that various modifications and alterations of the present invention are possible. Accordingly, it should be understood that the present invention can be carried out in embodiments not specified herein, within the technical scope based on the claims. The contents of the above-mentioned patent documents and the patent documents listed below are all incorporated herein as part of the content of this specification.

[0013] The heating device of this disclosure is used to apply heat to an object to be heated by bringing it into contact with the object to be heated during use. The objects to be heated may include, but are not limited to, the skin and mucous membranes of the human eyes, mouth, nose and surrounding areas, or the skin and mucous membranes of the throat, face, scalp, neck, arms, shoulders, legs, knees, abdomen, back, waist, buttocks, etc.

[0014] Examples of the heating device of this disclosure include, but are not limited to, the following embodiments (a) to (d). (a) An eye mask configured to be retainable over and around the eyes. (b) An adhesive form configured to be retained on the neck, arms, shoulders, legs, elbows, knees, forehead, abdomen, back, or waist. (c) A form of face mask configured to be held in place over the mouth, nose and surrounding area, or over the entire face. (d) A cup shape configured to be able to come into contact with the mouth, nose and surrounding area. All disclosures herein are applicable to all aspects of (a) through (d) described above.

[0015] The heating device of this disclosure is equipped with a heating element. The heating element preferably contains (1) powder of an oxidizable metal, (2) powder of a carbon material, (3) powder of a porous material, and (4) water. The powder of an oxidizable metal has the function of generating heat through oxidation reactions with oxygen in the air, thereby enabling the application of heat to an object to be heated. Carbon material powders have the function of accelerating the oxidation reaction of oxidizable metals, thereby efficiently generating heat. Porous material powders have the function of supplying water, which acts as a reaction medium, to the reaction system when carbon material powders promote the oxidation reaction of oxidizable metals, thereby increasing the exothermic efficiency. In this disclosure, porous materials included in the heating element exclude oxidizable metals and carbon materials. In other words, the heating element includes porous materials other than both oxidizable metals and carbon materials. Water has the function of facilitating interaction between powdered metals that are susceptible to oxidation and carbon materials that act as catalysts for oxidation reactions. The heating element preferably comprises a mixture containing the materials (1) to (4) described above.

[0016] The heating element is preferably configured as a sheet-like material. A "sheet-like material" is a thin object having two opposing surfaces, with a small thickness between those surfaces, and possessing flexibility and shape retention properties. 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. Furthermore, the sheet-like material has a thickness of 3.0 mm or less, preferably 2.8 mm or less, and more preferably 2.0 mm or less.

[0017] It is preferable that the heating element constituting the heating device is configured to generate heat by reacting with oxygen in the air, and that this heat generation produces water vapor heated to a predetermined temperature. In this case, some of the water contained in the heating element may evaporate into water vapor due to the heat generated by the oxidation reaction of the oxidizable metal.

[0018] Examples of the heating element's form include the forms shown in (i) and (ii) below. One form of a heating element is (i) a sheet-like material in which the heating element consists of a base sheet and a layer of a heating composition provided on one side thereof. In this case, the exothermic composition is obtained by applying a paste containing powder of an oxidizable metal, powder of a carbon material, powder of a porous material, and water to one side of a substrate sheet. In the following explanation, the form of the heating element described in (i) above will also be referred to as the "coated type".

[0019] Another form of the heating element is (ii) a form in which the heating element comprises, as a heating composition, powder of an oxidizable metal, powder of a carbon material, powder of a porous material, and water, preferably further comprising a fibrous material, and the mixture thereof is formed into a sheet by papermaking. In the following explanation, the form of the heating element described in (ii) above will also be referred to as the "papermaking type".

[0020] The heating element may be used in either form (i) or (ii) as is. Alternatively, a heating element in either form (i) or (ii) may be used, housed in a breathable packaging material. Furthermore, it is preferable that the packaging material prevents solids from flowing in or out. When a heating element is housed within packaging, the packaging is considered a separate entity from the heating element. In other words, the packaging does not constitute the heating element.

[0021] The shape of the packaging material is not particularly limited, but a flat shape is preferred. When forming the packaging material into a flat shape, it is also preferable that the packaging material is formed by laminating two sheets of material together such that one side is made up of a first sheet material that is breathable and the other side is made up of a second sheet material that is less breathable than the first sheet material.

[0022] One embodiment of the heating element described above is shown, for example, in Figures 1(a) and (b). Figure 1(a) shows an example of a coating-type heating element, and Figure 1(b) shows an example of a papermaking-type heating element. In Figures 1(a) and (b), each component is 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, a powder of a porous material 3c, a fiber material 33, and a packaging material 35.

[0023] In a heating device, it is preferable that the heating element has a predetermined content ratio among the following: the ratio of oxidizable metal to water, the ratio of oxidizable metal to porous material, and the ratio of water to porous material.

[0024] More specifically, the value obtained by multiplying the ratio of the water content to the mass content of the oxidizable metal powder contained in the heating element by 100 [100 × (water / oxidizable metal powder)] is preferably 30 or more, more preferably 40 or more, even more preferably 80 or more, and even more preferably 110 or more. Furthermore, the value obtained by multiplying the ratio of the water content to the mass content of the oxidizable metal powder contained in the heating element by 100 [100 × (water / oxidizable metal powder)] is preferably 270 or less, more preferably 250 or less, even more preferably 220 or less, and even more preferably 160 or less. In this disclosure, the "value obtained by multiplying the ratio of the mass content of water to the mass content of the oxidizable metal powder by 100" is calculated by the formula "100 × (mass of water [g] / mass of oxidizable metal powder [g])". By using this ratio of oxidizable metal to water, it is possible to achieve heating properties equivalent to or better than conventional heating devices, even when the amount of oxidizable metal is lower than that of conventional heating devices. In addition, it is possible to reduce the manufacturing cost of heating devices. In this disclosure, "reduction of manufacturing costs" means that, compared to conventional heating devices, the amount of oxidizable metal contained in the heating element can be reduced while maintaining or improving the heating characteristics to the same level or higher.

[0025] Depending on its form, it is even more preferable that the heating element constituting the heating device has a predetermined ratio of oxidizable metal powder to water within a set range. The forms of the heating elements described in (i) and (ii) above differ in their manufacturing methods. Furthermore, the form of the heating element may be used differently depending on the intended heating device. Therefore, the preferred range for the ratio of oxidizable metal powder to water contained in the heating element is explained below, categorized according to the form of the heating element.

[0026] In more detail, when the heating element is in a coated form, the value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal contained in the heating element by 100 [100 × (water / powder of the oxidizable metal)] is preferably 80 or more, more preferably 90 or more, and even more preferably 110 or more. Furthermore, when the heating element is in a coated form, the value obtained by multiplying the ratio of the water content to the mass content of the oxidizable metal powder contained in the heating element by 100 [100 × (water / oxidizable metal powder)] is preferably 270 or less, more preferably 220 or less, and even more preferably 160 or less. By using this ratio of oxidizable metal to water in the coating type, it is possible to achieve heating properties equivalent to or better than conventional methods, even when the amount of oxidizable metal is lower than in conventional heating devices. By adjusting the content of oxidizable metals and water to a more favorable range, in addition to the excellent heat generation characteristics described above, it is possible to reduce the manufacturing costs of heating devices. Furthermore, by adjusting the content of oxidizable metals and water to an even more favorable range, in addition to the excellent heating properties and reduced manufacturing costs mentioned above, the manufacturing efficiency of heating devices equipped with heating elements can be improved.

[0027] Alternatively, if the heating element is of the papermaking type, the value obtained by multiplying the ratio of the water content to the mass content of the oxidizable metal powder contained in the heating element by 100 [100 × (water / oxidizable metal powder)] is preferably 30 or more, more preferably 35 or more, and even more preferably 40 or more. Furthermore, when the heating element is of the papermaking type, the value obtained by multiplying the ratio of the mass content of water to the mass content of oxidizable metal powder contained in the heating element by 100 [100 × (water / oxidizable metal powder)] is preferably 80 or less, more preferably 70 or less, and even more preferably 60 or less. By using this ratio of oxidizable metal to water in the papermaking type, it is possible to achieve heating properties equivalent to or better than conventional heating devices, even when the amount of oxidizable metal is lower than in conventional heating devices. By adjusting the content of oxidizable metals and water within a more favorable range in the papermaking type, it is possible to reduce the manufacturing cost of heating devices in addition to achieving the excellent heat generation characteristics described above. Furthermore, by adjusting the content of oxidizable metals and water in the papermaking type to an even more favorable range, in addition to achieving the excellent heat generation characteristics and reducing manufacturing costs mentioned above, the manufacturing efficiency of heating devices equipped with heating elements can be improved.

[0028] Examples of oxidizable metal powders that constitute the heating element include iron, aluminum, zinc, manganese, magnesium, and calcium powders. These can be used individually or in combination of two or more. Among these, metallic iron is preferred in terms of ease of handling, safety, and manufacturing cost. In other words, iron powder is preferred. Examples of iron powder include one or more types selected from reduced iron powder and atomized iron powder. The powder of the oxidizable metal constituting the heating element may be an aggregate of metal particles that do not have pores on their surface, or it may be an aggregate of porous metal particles.

[0029] The carbon material powder constituting the heating element may have a function to promote oxidation reactions, specifically, one or more functions among oxygen retention and supplying material to the oxidizable metal and catalytic activity. Examples of such carbon materials include activated carbon such as coconut shell charcoal, charcoal powder, calcite charcoal, peat, and lignite, as well as powders of carbon black, acetylene black, and graphite. These can be used individually or in combination of two or more. Among these, activated carbon powder is preferably used as the carbon material powder because it has a good balance between oxygen supply capacity and catalytic activity.

[0030] As the porous material powder constituting the heating element, substances other than the oxidizable metals and carbon materials mentioned above can be used as powder. Porous materials can be those that have the function of retaining moisture, and are preferably porous inorganic compounds. Specific examples of porous materials include silicon-containing inorganic compounds such as zeolites, silica, vermiculite, perlite, and calcium silicate. These can be used individually or in combination of two or more. Diatomaceous earth is excluded from the porous materials in this disclosure. In other words, it is preferable that the porous material does not contain diatomaceous earth. Further, the porous material may be an anhydride or a hydrate. The pores formed in the porous material may be of an open-cell type, a closed-cell type, or a combination thereof.

[0031] When calcium silicate is used as the porous material, examples of the calcium silicate include gyrolite-based compounds, wollastonite-based compounds, tobermorite-based compounds, and calcium silicate hydrate-based compounds. These can be used alone or in combination of two or more.

[0032] Specifically, examples of the gyrolite-based compounds include gyrolite (Ca 16 (Si8O 20 )3(OH)8·14H2O), truscottite (Ca 14 (Si8O 20 )(Si 16 O 38 )8·2H2O), and Z-phase (Ca(Si2O5)·2H2O), etc. Examples of the wollastonite-based compounds include nekoite (Ca3(Si6O 15 )·8H2O), okite (Ca3(Si6O 15 )·6H2O), zonotlite (Ca6(Si6O 17 )(OH)·2), foschaelite (Ca4(Si3O9)(OH)·2), and hirnebrandite (Ca2(SiO3)(OH)·2), etc. Examples of the tobermorite-based compounds include 14 Å tobermorite (Ca5(Si6O 18 H2)·8H2O), 11 Å tobermorite (Ca5(Si6O 18 H2)·4H2O), and 9 Å tobermorite (Ca5(Si6O 18 H2)), etc. of tobermorite, and metastable calcium silicate (Ca / Si molar ratio of 0.8 to 2.0), etc. Examples of calcium silicate hydrate compounds include tricalcium silicate hydrate (Ca6(Si2O7)(OH)6) and α-dicalcium silicate hydrate (Ca2(SiO4H)(OH)). The calcium silicate mentioned above may be a commercially available product. For example, fluorite®, a gyrolite compound, can be used as a commercially available product.

[0033] From the viewpoint of obtaining a heating element with improved exothermic properties due to a good balance between water retention capacity and water supply capacity, and efficient progress of the oxidation reaction of oxidizable metals, it is preferable that the porous material contains the silicon-containing inorganic compound described above. When a silicon-containing inorganic compound is included as a porous material, from the viewpoint of further improving the heat generation characteristics, the content of the silicon-containing inorganic compound in the porous material is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass. From a similar viewpoint, it is more preferable that the silicon-containing inorganic compound consists of one or more of silica and calcium silicate. Furthermore, from the viewpoint of obtaining a heating element with excellent heat generation characteristics and water vapor generation, it is even more preferable that the silicon-containing inorganic compound is made of calcium silicate. Furthermore, from the viewpoint of obtaining a heating element with even better heat generation characteristics, it is more preferable to use at least one of gyrolite, xonotlite, and tobermorite as the porous material, and even more preferable to use gyrolite.

[0034] Next, another embodiment of the heating element in a heating device will be described. In the following description, we will mainly describe the components that differ from the embodiments described above, and omit the description of components that are similar. For components that are not specifically described in this embodiment, the descriptions of the embodiments described above will apply as appropriate.

[0035] In this embodiment, it is preferable that the heating element has a predetermined ratio of the mass content of porous material powder to the powder of oxidizable metal. By adjusting the proportions of oxidizable metals and porous materials to a predetermined level, it is possible to achieve heating properties equivalent to or better than conventional heating devices, even when the content of oxidizable metals is lower than that of conventional heating devices. In addition, it is possible to reduce the manufacturing cost of heating devices equipped with heating elements.

[0036] The heating element in this embodiment preferably contains powder of an oxidizable metal, powder of a carbon material, powder of a porous material, and water, similar to the embodiments described above. Furthermore, the heating element in this embodiment is preferably a sheet-like material. Furthermore, the heating element in this embodiment is preferably a coated or paper-made sheet-like material. Furthermore, it is preferable that the heating element in this embodiment reacts with oxygen in the air to generate heat, and that this heat generation produces water vapor heated to a predetermined temperature.

[0037] In this embodiment, the heating element has a value [100 × (porous material powder / oxidizable metal powder)] which is the ratio of the mass content of the porous material powder to the mass content of the oxidizable metal powder multiplied by 100, preferably 1 or more, more preferably 3 or more, and even more preferably 5 or more. Furthermore, the value obtained by multiplying the ratio of the content mass of the porous material powder to the content mass of the oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is preferably 25 or less, more preferably 20 or less, and even more preferably 15 or less. This ratio allows the oxidation reaction of the oxidizable metal to proceed sufficiently and sustainably, resulting in a heating device with excellent heat generation properties. In addition, it can reduce the manufacturing cost of the heating device. In this disclosure, the "value obtained by multiplying the ratio of the mass content of the porous material powder to the mass content of the oxidizable metal powder by 100" is calculated by the formula "100 × (mass of porous material powder [g] / mass of oxidizable metal powder [g])".

[0038] The ratio of oxidizable metals to porous materials in the heating element described above may also be set within a predetermined range, depending on the type of heating device and the desired properties and effects to be achieved.

[0039] In detail, for example, when the heating device is in the form of an eye mask and the aim is to reduce manufacturing costs, from the viewpoint of sustainably exhibiting heating characteristics equivalent to or better than conventional devices, the value obtained by multiplying the ratio of the content mass of porous material powder to the content mass of oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is preferably 1 or more, more preferably 3 or more, and even more preferably 5. Furthermore, in the same configuration, from the viewpoint of efficiently reducing manufacturing costs by reducing the content of oxidizable metals compared to conventional heating devices, the value obtained by multiplying the ratio of the content of porous material powder to the content of oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less.

[0040] As another embodiment relating to the content ratio of oxidizable metal and porous material, for example, when the heating device is in the form of an eye mask and the aim is to increase the amount of water vapor generated, from the viewpoint of sustainably exhibiting heating characteristics equivalent to or better than conventional methods, the value obtained by multiplying the ratio of the content mass of porous material powder to the content mass of oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more. Furthermore, in the same configuration, from the viewpoint of facilitating the continuous generation of water vapor and increasing the amount of water vapor generated, the value obtained by multiplying the ratio of the content mass of the porous material powder to the content mass of the oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is preferably 20 or less, more preferably 18 or less, and even more preferably 14 or less.

[0041] As yet another embodiment relating to the content ratio of oxidizable metals and porous materials, for example, when the heating device is in the form of a face mask or a cup, from the viewpoint of continuously providing a warming sensation to the object to be heated even when the heating device is separated from the object to be heated, the value obtained by multiplying the ratio of the content mass of porous material powder to the content mass of oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is preferably 3 or more, more preferably 5 or more, and even more preferably 6 or more. Furthermore, from the viewpoint of facilitating the sustained generation of water vapor and increasing the amount of water vapor generated, the value obtained by multiplying the ratio of the content mass of the porous material powder to the content mass of the oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is preferably 15 or less, more preferably 11 or less, and even more preferably 8 or less.

[0042] Next, we will describe yet another embodiment of the heating element in a heating device. In the following description, as with the embodiments described above, we will mainly describe the components that differ from those in the embodiments described above, and omit the description of components that are similar. For components that are not specifically described in this embodiment, the descriptions of the embodiments described above will apply as appropriate.

[0043] In this embodiment, it is preferable that the heating element has a predetermined ratio of the mass content of porous material powder to water. By setting the water and porous material to a predetermined ratio, it is possible to achieve heating properties equivalent to or better than conventional heating devices, even when the content of oxidizable metals is lower than that of conventional heating devices. In addition, it is possible to reduce the manufacturing cost of heating devices.

[0044] The heating element in this embodiment preferably contains powder of an oxidizable metal, powder of a carbon material, powder of a porous material, and water, similar to the embodiments described above. Furthermore, the heating element in this embodiment is preferably a sheet-like material. Furthermore, the heating element in this embodiment is preferably a coated or paper-made sheet-like material. Furthermore, it is preferable that the heating element in this embodiment reacts with oxygen in the air to generate heat, and that this heat generation produces water vapor heated to a predetermined temperature.

[0045] In this embodiment, the heating element has a value obtained by multiplying the ratio of the mass content of the porous material powder to the mass content of water by 100 [100 × (porous material powder / water)] which is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. Furthermore, the value obtained by multiplying the ratio of the mass content of the porous material powder to the mass content of water contained in the heating element by 100 [100 × (porous material powder / water)] is preferably 30 or less, more preferably 20 or less, and even more preferably 15 or less. This configuration allows for an appropriate balance between the supply of water, which promotes the oxidation reaction of the oxidizable metal, and the supply of oxygen from the atmosphere, through the pores of the porous material. This enables the oxidation reaction of the oxidizable metal to proceed sufficiently and sustainably, resulting in a heating device 1 with excellent heat generation properties. In addition, it is possible to reduce the manufacturing cost of the heating device.

[0046] In the heating element of each embodiment described above, the content ratio of oxidizable metal to water, the content ratio of oxidizable metal to porous material, and the content ratio of water to porous material may be such that one of them satisfies the preferred content ratio, any two of them satisfies the preferred content ratio, or all of them satisfies the preferred content ratio.

[0047] In other words, the heating element may satisfy only the preferred content ratio of the oxidizable metal to water, or only the preferred content ratio of the oxidizable metal to the porous material, or only the preferred content ratio of water to the porous material. By having any of the above-described configurations, it is possible to achieve heating properties equivalent to or better than conventional heating devices, even when the content of oxidizable metals is lower than that of conventional heating devices.

[0048] Furthermore, the heating element may satisfy both a suitable content ratio of oxidizable metal to water and a suitable content ratio of oxidizable metal to porous material, or it may satisfy both a suitable content ratio of oxidizable metal to water and a suitable content ratio of water to porous material, or it may satisfy both a suitable content ratio of oxidizable metal to porous material and a suitable content ratio of water to porous material. By having any combination of the above-described configurations, a good balance between oxygen supply capacity and catalytic capacity can be maintained, so even when the content of oxidizable metals is lower than in conventional heating devices, even better heating characteristics can be achieved.

[0049] The heating element may satisfy all of the following conditions: a suitable ratio of oxidizable metal to water, a suitable ratio of oxidizable metal to porous material, and a suitable ratio of water to porous material. By creating a heating element that satisfies all of these requirements, the balance between oxygen supply capacity and catalytic capacity can be further improved, allowing the oxidation reaction of the oxidizable metal to proceed sufficiently and sustainably. As a result, even when the content of the oxidizable metal is lower than that of conventional heating devices, it is possible to efficiently exhibit heating characteristics that are equal to or better than those of conventional devices. In addition, it is possible to further reduce the manufacturing costs of heating elements and heating devices equipped with them. Furthermore, the manufacturing efficiency of heating elements and heating devices equipped with them can be further improved.

[0050] The following describes matters that apply to all of the embodiments described above. From the viewpoint of obtaining a heating device with excellent heat generation characteristics and the ability to sustainly exhibit said heat generation characteristics with high productivity, the pore diameter D1 of the particles constituting the porous material powder is preferably 0.01 μm or more, more preferably 0.02 μm or more, even more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and even more preferably 0.15 μm or more. Furthermore, the pore diameter D1 of the particles constituting the porous material powder is preferably 5 μm or less, more preferably 1 μm or less, even more preferably 0.8 μm or less, even more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. When calcium silicate is used as the porous material, the pore diameter D1 of the particles is more preferably 0.02 μm or more, even more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and even more preferably 0.15 μm or more. When calcium silicate is used as the porous material, the pore diameter D1 of the particles is more preferably 0.8 μm or less, even more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. By setting the pore diameter D1 of the porous material within this range, moisture retained in the porous material powder can be efficiently transferred to the oxidizable metal side, further enhancing the heat generation properties. The effects described above become more pronounced when the pore diameter D1 is within a more preferable range, and even more pronounced when the pore diameter D1 is within an even more preferable range.

[0051] The pore diameter D1 of the porous material described above can be measured, for example, by the mercury intrusion method specified in JIS R1655. Furthermore, when two or more porous materials are blended, the pore diameter D1 shall be the value measured for the mixture of porous materials.

[0052] The pore diameter can be measured by the mercury intrusion method specified in JIS R1655, for example, by the following method: First, 0.02 g to 0.1 g of the porous material powder to be measured is used as the measurement sample. The measurement cell containing the measurement sample is set in a mercury porosimeter (e.g., Autopore IV9500, manufactured by Micromeristics), and the cumulative pore volume V (cm³) of the measurement sample is increased within a predetermined range. 3 The pore diameter (dV / g) is then measured. Next, the converted pore diameter D (μm), calculated according to the following formula (A), is plotted on the horizontal axis, and the log differential pore volume (dV / d(log)) is plotted on the horizontal axis. 10 D);cm 3The relationship with ( / g) is plotted on the vertical axis to obtain the 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 respect to the logarithm of the pore diameter D is plotted on the vertical axis to obtain the pore volume distribution. D = 4γcosθ / P ···(A) (γ: surface tension of mercury, θ: contact angle, P: mercury injection pressure)

[0053] The above measurements are performed at 22°C and under 65% RH conditions. 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 sum of 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 diameter in the distribution curve is defined as the pore diameter D1 (μm) in this disclosure.

[0054] The porous material powder has an oil absorption capacity of preferably 300 mL / 100 g or more, more preferably 350 mL / 100 g or more, and even more preferably 400 mL / 100 g or more. Furthermore, the oil absorption capacity of the porous material powder is preferably 900 mL / 100 g or less, more preferably 800 mL / 100 g or less, and even more preferably 700 mL / 100 g or less. This range of oil absorption allows the water contained in the heating element to be sufficiently retained by the porous material particles, and also enables more efficient transfer of the water retained by the porous material to the oxidizable metal side, thereby continuously and efficiently enhancing the heating properties.

[0055] The oil absorption capacity of porous materials can be measured according to JIS K5010-13-2. Specifically, 1 to 5 g of the powder sample to be measured is placed in the center of the measuring plate, and boiled linseed oil is dropped from a burette into the center of the sample at a time, mixing thoroughly with a palette knife each time. The dropping of boiled linseed oil and mixing of the sample are repeated until the entire sample becomes a hard, putty-like mass, at which point boiled linseed oil is added and mixed in. The endpoint is when the sample can be rolled into a spiral shape using a palette knife after adding one drop of boiled linseed oil, and the amount of boiled linseed oil added at this point (mL) is read from the scale. However, if the sample cannot be rolled into a spiral shape, the endpoint is when the sample is just before it suddenly softens after adding one drop of boiled linseed oil, and the amount of boiled linseed oil added at this point (mL) is read from the scale. The amount of powder sample to be used for measurement shall be determined in accordance with the provisions of JIS K5010-13-2, after conducting preliminary tests to confirm the approximate value of the oil absorption amount in advance. Furthermore, if two or more porous materials are included, the oil absorption amount will be measured based on the mixture of porous materials. The amount of drops (mL) obtained according to the method described above is converted to an amount per 100g of the powder sample to be measured, and the oil absorption amount (mL / 100g) according to this disclosure is calculated.

[0056] When the powder of an oxidizable metal is composed of particles having pores on its surface, it is preferable that the pore diameter D2 of the particles constituting the oxidizable metal powder is smaller than the pore diameter D1 of the porous material powder. This configuration allows for more efficient transfer of water held by the porous material to the oxidizable metal side due to differences in capillary action, thereby further enhancing the heat generation characteristics.

[0057] More specifically, the pore diameter D2 of the particles constituting the powder of the oxidizable metal is preferably 0.001 μm or larger, more preferably 0.003 μm or larger, and even more preferably 0.006 μm or larger. The pore diameter D2 of the particles constituting the powder of the oxidizable metal is preferably 0.07 μm or less, more preferably 0.05 μm or less, and even more preferably 0.01 μm or less. By setting the range in this manner, the difference in capillary force allows water held by the porous material to be efficiently drawn to the metal to be oxidized, thereby further promoting the oxidation reaction of the metal to be oxidized and further enhancing its exothermic properties. Such powders of oxidizable metals can be produced, for example, by the method disclosed in EP3626367 A1.

[0058] The pore diameter D2 of the oxidizable metal powder described above can be measured by the mercury intrusion method specified in JIS R1655, for example, using the following method. Specifically, 0.02 g to 0.1 g of the oxidizable metal powder is used as the measurement sample, the measurement cell containing the sample is set in a mercury porosimeter (e.g., Autopore IV9500, manufactured by Micromeristics), and the cumulative pore volume V (cm³) of the measurement sample is increased within a predetermined range. 3 The pore diameter (dV / g) is then measured. Next, the converted pore diameter D (μm), calculated according to the following formula (A), is plotted on the horizontal axis, and the log differential pore volume (dV / d(log)) is plotted on the horizontal axis. 10 D);cm 3 The relationship with ( / g) is plotted on the vertical axis to obtain the 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 respect to the logarithm of the pore diameter D is plotted on the vertical axis to obtain the pore volume distribution. D = 4γcosθ / P ···(A) (γ: surface tension of mercury, θ: contact angle, P: mercury injection pressure)

[0059] The above measurements are performed under conditions 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 sum of 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 diameter in the distribution curve is defined as the pore diameter D2 (μm) in this disclosure.

[0060] From the viewpoint of achieving both continuous generation of water vapor and appropriate progress of the oxidation reaction, it is also preferable to further arrange a water-absorbing resin in or near the heating element. From the viewpoint of achieving both continuous generation of water vapor and appropriate progress of the oxidation reaction, as well as preventing unintended detachment of constituent materials and further improving manufacturing efficiency, when a water-absorbent resin is further added, it is even more preferable to further arrange a packaging material so that a layer containing water-absorbent resin powder is placed between the heating composition in the heating element and the packaging material. Each of the above-described forms is applicable to both coating-type and papermaking-type applications. By further distributing a water-absorbing resin in or near the heating element, excess moisture present in the heating element can be absorbed. As a result, the oxidation reaction of the oxidizable metal can proceed efficiently, improving the heating properties, and the moisture held in the water-absorbing resin and heating element can be continuously released as water vapor, providing a comfortable warming sensation to the user of the heating device.

[0061] When a water-absorbing resin is further placed inside or near the heating element, one possible configuration of the water-absorbing resin is to have the powder of the water-absorbing resin mixed with the powders of the oxidizable metal, carbon material, and porous material of the heating composition in the heating element, as well as water. In this case, the powder of the water-absorbing resin constitutes a part of the heating element.

[0062] Alternatively, another configuration of the superabsorbent resin is one in which a layer containing superabsorbent resin powder exists adjacent to the heating element. In this case, the layer containing superabsorbent resin powder is constructed separately from the heating element. Examples of configurations in which a layer containing water-absorbent resin powder exists adjacent to a heating element include: (a) a configuration having a single layer formed by sandwiching water-absorbent resin powder between two moisture-permeable sheets; (b) a configuration in which water-absorbent resin powder is in contact with the heating composition constituting the heating element without the use of other members, and is arranged in a single layer; or (c) a configuration in which a laminated structure is arranged in which a first water-absorbent resin layer, in which water-absorbent resin powder is arranged adjacent to the first water-absorbent resin layer, 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, is arranged without the use of other members, and the heating composition constituting the heating element. In other words, in any of the cases (a) to (c) described above, it is preferable that the heat-generating composition constituting the heat-generating element is placed between the base sheet and the layer containing the water-absorbent resin powder.

[0063] Alternatively, another embodiment of the superabsorbent resin is one in which a layer containing superabsorbent resin powder is arranged as a base sheet and is adjacent to the heat-generating composition in the heating element. In this case, the superabsorbent resin powder constitutes a part of the heating element. In the layer containing the water-absorbent resin powder, it is preferable that the water-absorbent resin is sandwiched between two moisture-permeable sheets. In this case, it is also preferable that the heat-generating composition in the heating element is placed in contact with the outer surface of one of the moisture-permeable sheets.

[0064] When a layer containing water-absorbent resin powder is provided as a base sheet, it is preferable that the layer containing water-absorbent resin powder be housed together with the heating element within the packaging material, from the viewpoint of preventing unintended detachment of the constituent materials. If packaging material is provided, it is also preferable that the packaging material is formed by laminating together such that one side is made of a first sheet material that is breathable and the other side is made of a second sheet material that is less breathable than the first sheet material. The packaging material is preferably flattened. When a layer containing water-absorbent resin powder is provided as a base sheet and packaging material is also provided, it is even more preferable that the layer containing water-absorbent resin powder and the first sheet material in the packaging material, which is breathable, are arranged to face each other.

[0065] Regarding the arrangement of the heating element and the water-absorbing resin, one configuration in which a layer containing water-absorbing resin powder exists adjacent to the heating element is illustrated in Figures 2(a) to (c). In the embodiments shown in Figures 2(a) to (c), a layer 3L containing water-absorbent resin powder (hereinafter also referred to as the water-absorbent resin layer 3L) is placed between the heating element 3 and the packaging material 35. Note that the heating element 3, the water-absorbing resin layer 3L, and the packaging material 35 shown in Figures 2(a) to (c) are depicted as having different overall thicknesses, but this is only for the sake of explanation. In the actual configurations of the heating element 3, the water-absorbing resin layer 3L, and the packaging material 35 in Figures 2(a) to (c), their thicknesses may be the same or different.

[0066] In more detail, when a water-absorbing resin layer 3L is provided, it is preferable that the water-absorbing resin layer 3L is formed by sandwiching a water-absorbing resin 37 between two moisture-permeable sheets 38, 38, as shown in Figure 2(a). In this case, it is also preferable that the water-absorbing resin layer 3L is in contact with the heat-generating composition 30 constituting the heat-generating element 3 via the moisture-permeable sheet 38. More specifically, it is preferable that the heat-generating composition 30 constituting the heat-generating element 3 is placed between the base sheet 31 and the water-absorbent resin layer 3L. This configuration allows for the continuous release of water vapor while maintaining excellent heating properties, generating more water vapor than conventional heating devices. As a result, it provides a comfortable warmth and moisture to the target area such as the eyes, nose, and throat, and this sensation is continuously perceived. The configuration of the water-absorbing resin layer is advantageous in that, for example, when applied to a heat-retaining device preferably in the form of an eye mask or adhesive, it can continuously provide a feeling of warmth to the user's eyes and surrounding areas, thereby providing comfort to the user.

[0067] Alternatively, as shown in Figure 2(b), it is also preferable that the water-absorbing resin layer 3L is arranged in a layer such that the water-absorbing resin 37 is in contact with the heat-generating composition 30 constituting the heat-generating element 3 without any other components in between. More specifically, it is preferable that the heat-generating composition 30 constituting the heat-generating element 3 is placed between the base sheet 31 and the water-absorbent resin layer 3L. This configuration allows for the generation of even more water vapor than conventional heating devices, thus increasing the amount of water vapor produced and providing the advantage of simultaneously providing a comfortable warmth and moisture to the heated areas such as the eyes, nose, mouth, and throat. The configuration in the water-absorbent resin layer is advantageous in that, for example, when applied to a heating device preferably in the form of a face mask, it can provide the user with a feeling of warmth and moisture over a wide area around their mouth and nose, thereby providing comfort to the user.

[0068] Alternatively, as shown in Figure 2(c), it is preferable that the water-absorbing resin layer 3L has a laminated structure in which a first water-absorbing resin layer 3s is arranged adjacent to the heat-generating composition 30 constituting the heat-generating element 3 and the water-absorbing resin 37 without any other members in between, and a second water-absorbing resin layer 3t is arranged adjacent to the first water-absorbing resin layer 3s and is formed by sandwiching the water-absorbing resin 37 between two moisture-permeable sheets 38, 38. More specifically, it is preferable that the heat-generating composition 30 constituting the heat-generating element 3 is placed between the base sheet 31 and the water-absorbent resin layer 3L. In the embodiment shown in Figure 2(c), the water-absorbing resin layer 3L has a laminated structure in which the first water-absorbing resin layer 3s and the second water-absorbing resin layer 3t are arranged in contact with each other. This configuration allows the heating element to efficiently carry out its exothermic reaction, generating a large amount of water vapor in a relatively short time, thus enabling the heated objects such as the eyes, nose, mouth, and throat to perceive warmth and moisture early on. The configuration in the water-absorbent resin layer is advantageous in that, for example, when applied to a heating device preferably in the form of a cup, it can intensively provide warmth and moisture to the user's mouth and nose and the surrounding area in a short period of time.

[0069] Regarding the arrangement of the heating element and the water-absorbing resin, another configuration in which a layer containing water-absorbing resin powder exists adjacent to the heating composition in the heating element is illustrated in Figure 3. In the embodiment shown in Figure 3, a water-absorbent resin layer 3L is arranged between the heating element 30 and the packaging material 35. As shown in Figure 3, it is preferable that the water-absorbing resin layer 3L is formed by sandwiching a water-absorbing resin 37 between two moisture-permeable sheets 38, 38. Furthermore, as shown in Figure 3, it is preferable that the heat-generating composition 30 in the heat-generating element 3 is in contact with one side of the moisture-permeable sheet 38. In this case, it is also preferable that the water-absorbing resin layer 3L be the base sheet 31 in the heat-generating element 3. As shown in Figure 3, when the water-absorbent resin layer 3L is provided as a base sheet 31 and a flat packaging material 35 is provided, it is even more preferable that the water-absorbent resin layer 3L and the first sheet material with breathability in the packaging material are arranged to face each other. This configuration allows for the continuous release of water vapor while maintaining excellent heating properties, generating more water vapor than conventional heating devices. As a result, it provides a comfortable warmth and moisture to the target area such as the eyes, nose, and throat, and this sensation is continuously perceived. The configuration of the water-absorbing resin layer is advantageous in that, for example, when applied to a heat-retaining device preferably in the form of an eye mask or adhesive, it can continuously provide a feeling of warmth to the user's eyes and surrounding areas, thereby providing comfort to the user.

[0070] When the water-absorbing resin layer is placed adjacent to the heating element, the water-absorbing resin layer is preferably configured as a sheet.

[0071] Specific examples of superabsorbent polymers include polymers or copolymers of starch, cross-linked carboxymethylated cellulose, acrylic acid or alkali metal acrylate salts, polyacrylic acid and its salts, and one or more polyacrylate graft polymers. Sodium salts can be used as the polyacrylate salts. Furthermore, the shape of the water-absorbing resin can include particles consisting of spherical, lumpy, grape-cluster-shaped, fibrous, or combinations thereof. The water-absorbing resin is preferably a powder consisting of aggregates of particles.

[0072] As a breathable sheet, for example, tissue paper, absorbent paper, nonwoven fabrics, or other fiber sheets or mesh sheets can be used. The breathable sheet preferably has breathability.

[0073] From the viewpoint of appropriately controlling the oxidation reaction and obtaining a heating device with good exothermic properties, the powder of the oxidizable metal preferably has a particle size of 1 μm or more, and more preferably 10 μm or more. From a similar viewpoint, the particle size of the particles constituting the powder of the oxidizable metal is preferably 200 μm or less, and more preferably 100 μm or less.

[0074] From the viewpoint of fully exhibiting catalytic activity in oxidation reactions and obtaining a heating device with good exothermic properties, the carbon material powder preferably has a particle size of 1 μm or more, and more preferably 10 μm or more. From a similar viewpoint, the particle size of the particles constituting the carbon material powder is preferably 200 μm or less, and more preferably 100 μm or less.

[0075] From the viewpoint of obtaining a heating device with good heating properties by appropriately controlling the retention and supply of water, the porous material powder preferably has a particle size of 1 μm or more, and more preferably 10 μm or more. From a similar viewpoint, the particle size of the particles constituting the porous material powder is preferably 200 μm or less, and more preferably 100 μm or less.

[0076] When using a water-absorbent resin in powder form, the particle size of the particles constituting the powder can be within the range commonly used in this art.

[0077] The particle size of each of the materials mentioned above can be, for example, the median diameter measured by the laser diffraction / scattering method using a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., model number: LA-950V2).

[0078] When the heating element is a papermaking-type sheet containing fibrous material, natural and synthetic fibrous materials can be used without particular limitation as the fibrous material. Examples of natural fiber materials include plant fibers (cotton, kapok, 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, sedge, coconut, rush, straw, etc.), animal fibers (wool, goat hair, mohair, cashmere, alcapa, angora, camel, vicuña, silk, feathers, down, feathers, algin fiber, chitin fiber, casein fiber, etc.), and mineral fibers (asbestos, etc.). These fiber materials can be used individually or in combination. Examples of synthetic fiber materials include semi-synthetic fibers (acetate, triacetate, acetate oxide, Promix, chlorinated rubber, hydrochloric acid rubber, etc.), synthetic polymer fibers (polyesters such as nylon, aramid, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polyacrylonitrile, acrylic, polyethylene, polyethylene, polypropylene, polystyrene, polyurethane, rayon, viscose rayon, cupro, etc.), metal fibers, carbon fibers, glass fibers, etc. These fiber materials can be used individually or in combination. Of these, from the viewpoint of achieving both uniform dispersion of oxidizable metals 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.

[0079] The fibrous material preferably has an average fiber length of 0.5 mm or more, more preferably 2 mm or more. Furthermore, the fiber material has an average fiber length of preferably 10 mm or less, and more preferably 5 mm or less. The average fiber length of a fibrous material is determined by measuring 50 or more fibrous materials, fixing one end of each fiber to a horizontal board, and allowing the fiber to hang downwards due to its own weight. The fiber length is measured using a fixing ruler, or by fixing the fiber on a microscope slide and measuring it with a microscope. The arithmetic mean of the obtained measurement results is then used.

[0080] From the viewpoint of facilitating the generation of water vapor associated with the heat generated by the heating element, it is preferable that the heating element contains an electrolyte. Examples of electrolytes included in the heating element include salts of alkali metals or alkaline earth metals with phosphoric acid or sulfuric acid, or one or more of the chlorides or hydroxides of alkali metals or alkaline earth metals. Of these, from the viewpoint of superior chemical stability and production cost, it is preferable to use one or more of the following as the electrolyte: tripotassium phosphate, potassium hydroxide, sodium chloride, and potassium chloride. The electrolyte may be used, for example, in powder form, or as a liquid dissolved or dispersed in a liquid medium such as water.

[0081] The heating element may consist only of powder of an oxidizable metal, powder of a carbon material, powder of a porous material, and water, and optionally fibrous material. Alternatively, in addition to the various powders and water, and optionally fibrous material, other powders other than powder of an oxidizable metal, powder of a carbon material, and powder of a porous material may be included in the heating composition. Other powders include, for example, one or more types of superabsorbent resins and electrolytes mentioned above. From the viewpoint of further improving the heating characteristics and the amount of water vapor generated, the content of other powders in the heating element is preferably 20% by mass or less, and more preferably 10% by mass or less, as expressed as the total mass ratio to the total powder constituting the heating element. The total mass ratio of oxidizable metal powder, carbon material powder, and porous material powder to the total powder constituting the heating element is preferably 80% by mass or more, and more preferably 90% by mass or more, from the viewpoint of further improving the heating characteristics and the amount of water vapor generated. If the powder contains a water-absorbing resin, its mass is based on the mass in its completely dry state.

[0082] A heating device having the above configuration further contains porous materials other than oxidizable metals and carbon materials in the sheet-like heating element, and by appropriately setting at least one of the content ratios of oxidizable metal to water, oxidizable metal to porous material, and water to porous material, the oxidation reaction of the oxidizable metal can be promoted. As a result, a heating device with a high sensible heat integrated amount, expressed as the integral of temperature and heat generation duration, and excellent heat generation characteristics can be obtained. Furthermore, even when the content of oxidizable metals is reduced compared to conventional heating devices, excellent heating properties can be achieved. Therefore, heating devices with heating properties equivalent to or better than conventional ones can be manufactured at a reduced cost. Furthermore, by appropriately setting at least one of the following in the heating element: the ratio of oxidizable metal to water, the ratio of oxidizable metal to porous material, and the ratio of water to porous material, it is possible to create a heating device with excellent heating characteristics and water vapor generation while suppressing manufacturing costs, regardless of the form of the heating device.

[0083] Generally, the oxidation reaction of oxidizable metals can be affected by the amount of moisture and oxygen present in the vicinity of the metal powder. More specifically, if there is an excessive amount of moisture surrounding the metal powder, the moisture acts as a barrier, making it difficult for the oxidizable metal to come into contact with oxygen. As a result, the oxidation reaction may not be sustained, or its initiation may be delayed. On the other hand, if the amount of moisture surrounding the metal powder is excessively low, the oxidizable metal and oxygen come into contact more easily, but water-mediated interactions with carbon materials that act as catalysts for the oxidation reaction become less likely to occur. As a result, the oxidation reaction does not last long enough, making it difficult to achieve the desired exothermic properties.

[0084] In this regard, it is presumed that by using a porous material, sufficient water can be retained in the pores of the porous material, and the water retained in the porous material is continuously supplied to the metal to be oxidized in an appropriate amount, thereby ensuring the amount of water and oxygen necessary for the continuous progress of the oxidation reaction. In particular, as the oxidation reaction progresses, pores are formed on the surface of the metal to be oxidized, making it porous. Due to the capillary force generated between the porous material and the metal to be oxidized, water is continuously supplied from the porous material to the metal to be oxidized. As a result, the oxidation reaction proceeds continuously, the heat generation is sustained for a long time, and the heating device becomes even more superior in terms of heating properties. This becomes even more pronounced when, as the porous material, preferably, the silicon-containing inorganic compounds mentioned above, more preferably calcium silicate, and even more preferably at least one of gyrolite, xonotlite, and tobermorite is used. Furthermore, due to the improved heat generation characteristics, the water contained in the heating element evaporates as heat is generated, producing more water vapor than conventional heating devices. This has the advantage of increasing the amount of water vapor produced, allowing the user of the heating device to continuously perceive a comfortable warmth. Furthermore, the improvements in the heat generation characteristics and water vapor generation described above can be easily achieved without depending on the presence or absence of breathable packaging materials or other sheet materials constituting the heating device, or the degree of breathability of the other sheet materials constituting the breathable packaging materials or heating device.

[0085] The heating device preferably comprises a main body and a heating element provided in the main body. The main body may also preferably have a shape that covers the object to be heated during use. The heating device preferably comprises a surface sheet located on the side closer to the object to be heated and a back sheet located on the side further away from the object to be heated. In more detail, it is preferable that the heating device comprises a surface sheet located closer to the user's skin and a back sheet located further away from the user's skin. Preferably, the main body of the heating device is composed of the surface sheet and the back sheet. It is preferable that the heating element is held between the surface sheet and the back sheet that constitute the main body. It is also preferable that the heating element is housed within a breathable packaging material and held between the surface sheet and the back sheet. When the packaging material is formed from a first sheet material and a second sheet material, it is preferable that the breathable first sheet material is positioned on the side closer to the object to be heated, and more specifically, on the side closer to the user's skin. In other words, it is preferable that the first sheet material is positioned opposite the surface sheet. When the packaging material is formed from a first sheet material and a second sheet material, it is preferable that the second sheet material, which has lower breathability than the first sheet material, be positioned on the side furthest from the object to be heated, and more specifically, on the side furthest from the user's skin. In other words, it is preferable that the second sheet material be positioned opposite the backing sheet. It is also preferable that the heating device is designed to generate steam heated to a predetermined temperature. This allows heat to be applied to the object to be heated and its surroundings.

[0086] An embodiment of a heating device will be described below with reference to the drawings. Figures 4 to 7 show a heating device in the form of a so-called eye mask, as one embodiment of the heating device. In other words, this disclosure includes the use of a heating device as an eye mask, as well as methods for using a heating device as an eye mask. In the following description, we will mainly describe the components that differ from the embodiments described above, and the same components will be denoted by the same reference numerals and their descriptions will be omitted. For components that are not specifically described in this embodiment, the descriptions of the components described above will apply as appropriate.

[0087] The heating device of this embodiment is configured to be held in place around the eyes. This heating device is used to apply heat to the eyes and surrounding area by being brought into contact with both eyes of the person being heated. The heating device is designed to generate steam heated to a predetermined temperature, thereby applying heat to the eyes and the surrounding area, which are the target of the heating process.

[0088] The heating device of this embodiment preferably comprises a horizontally elongated main body that has a shape that covers both of the user's eyes when in use, and a heating element provided in the main body. Furthermore, it is preferable that the heating device of this embodiment also includes a pair of ear loops attached to the main body. The ear loops allow the user's eyes to remain covered. In the following description of this embodiment, the direction corresponding to the longitudinal direction of the heating device is also referred to as the transverse direction, and the direction perpendicular to the transverse direction is also referred to as the longitudinal direction. In this embodiment, the heating device is illustrated in Figure 4 as a heating device 1, a main body 2, a heating element 3, and the horizontal direction X and vertical direction Y.

[0089] The heating device 1 shown in Figure 4 has ear loops 4 provided at both outer ends of the main body 2 in the lateral direction X, and these loops can be reversed outward in the lateral direction X. This allows each ear loop 4, 4 to be placed over the user's ears, thereby maintaining the coverage of the user's eyes by the main body 2. From the viewpoint of improving wearability, it is preferable that the sheet material constituting the ear hook portion 4 is a stretchable sheet.

[0090] Figure 5 shows an exploded perspective view of the heating device 1 of this embodiment. Figure 6 also shows a cross-sectional view of the heating device 1 along the lateral direction X. The main body 2 of the heating device 1 shown in Figures 5 and 6 is flat and comprises a surface sheet 5 located on the side closer to the user's skin and a back sheet 6 located on the side further away from the user's skin.

[0091] The surface sheet 5 comprises a surface that comes into contact with the heated body part, such as the eyes, mouth, or nose, when the heating device 1 is in use. The back sheet 6 is the side furthest from the user's skin and forms the outer surface of the heating device 1. In other words, in Figures 5 and 6, the upper part of the paper is the side closer to the user's skin, and the lower part of the paper is the side furthest from the user's skin.

[0092] The surface sheet 5 and the back sheet 6 shown in Figures 5 and 6 are joined together by an adhesive 7 such as a hot melt adhesive while they are superimposed on each other. As a result, two heating elements 3, 3 are housed between the two sheets 5, 6, spaced apart from each other in the lateral direction X. In other words, in this embodiment, the heating element 3 is configured to be inseparable from the main body 2. It is preferable that the heating element 3 is held between the surface sheet 5 and the back sheet 6 that constitute the main body 2. Of the surface sheet 5 and the back sheet 6, it is preferable that at least the surface sheet 5 is made of a breathable fiber sheet. A fiber sheet is an aggregate of constituent fibers that maintains its shape in a sheet form by at least one of the following means: entanglement, fusion, and adhesion. Detailed explanations of sheets 5 and 6 will be provided later.

[0093] The cross-sectional view shown in Figure 6 illustrates the fixed state of the heating element 3. As shown in Figure 6, it is also preferable that the heating element 3 is formed by bonding multiple sheet materials together by heat sealing or the like, and is housed in a breathable packaging material 35. In this case, it is also preferable that the heating element 3 is housed in a breathable packaging material 35 and held between the surface sheet 5 and the back sheet 6.

[0094] The packaging material 35 is preferably flat. In this case, it is also preferable that the packaging material 35 is formed by laminating two sheets of material, one of which is made up of a first sheet material that is breathable and the other side of which is made up of a second sheet material that is less breathable than the first sheet material. When the packaging material 35 is formed from a first sheet material and a second sheet material, it is preferable that the breathable first sheet material is positioned closer to the user's skin. In other words, it is preferable that the first sheet material is positioned opposite the surface sheet 5. When the packaging material 35 is formed from a first sheet material and a second sheet material, it is preferable that the second sheet material, which has lower breathability than the first sheet material, is positioned on the side furthest from the user's skin. In other words, it is preferable that the second sheet material is positioned opposite the back sheet 6.

[0095] When the heating device 1 is composed of a packaging material 35, it is preferable that, as shown in Figure 6, the outer surface of the packaging material 35 and the inner surface of the back sheet 6 of the heating device 1 are fixed by adhesive fixing parts 7a, 7a formed by adhesive 7, and the other surfaces are not fixed to the back sheet 6. In the embodiment shown in Figure 6, each adhesive fixing portion 7a, 7a is provided in the central area of ​​the heating device 1 in the lateral direction X and extends along the vertical direction Y of the heating device 1. This configuration allows the heating element 3 to be positioned with a high degree of fit to the object to be heated when the heating device 1 is in use, enabling efficient application of heat to the object to be heated.

[0096] Returning to Figure 5, as shown in the figure, it is preferable that the ear hook portion 4 is made of a sheet material, and that an insertion portion 4A extending in the lateral direction X is formed in the sheet material. The insertion portion 4A is a hole through which the ear canal portion 4 is placed when the ear canal is placed over 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 5 and 7, the ear hook portion 4 is joined to the outer surface of the surface sheet 5 of the main body portion 2 at both outer end regions in the lateral direction X, thereby forming a joining region 9 where the main body portion 2 and the ear hook portion 4 are joined. The joining region 9 also functions as a bending point when the ear hook portion 4 is reversed, with the joining end portion 9s as the axis.

[0097] Figure 7 is a cross-sectional view showing the configuration of the bonding region 9 in the heating device 1 of this embodiment. The joining region 9 between the main body 2 and the ear hook portion 4, as shown in Figures 5 and 7, is preferably continuously joined from the joining end portion 9s, which is the inner end in the lateral direction X of the joining region 9, to the outer end in the lateral direction X of the main body 2, and has a substantially semi-elliptical shape. As shown in Figure 7, it is preferable that the joining region 9 is formed by joining the surface sheet 5 of the main body 2 and the ear hook portion 4. Preferably, the joining region 9 also functions as a bending portion when the ear hook portion 4 is reversed with respect to the joining end portion 9s. The joint region 9 shown in Figures 5 and 7 is formed by continuous joining, but it may also be formed by intermittent joining.

[0098] The eye mask-shaped heating device 1 shown in Figures 4 to 7 can be used by holding it over the ears using the ear loops 4, as shown in Figure 8. This usage configuration allows for the uniform application of water vapor and heat generated from the heating device 1 to the user's eyes and surrounding area, regardless of the user's posture (e.g., supine or seated). This is advantageous because it improves the versatility of the usage configuration of the heating device 1.

[0099] Another embodiment of the heating device 1 will be described below with reference to Figure 9. Figure 9 shows a heating device having a so-called adhesive form as one embodiment of the heating device. In other words, this disclosure includes the use of a heat-retaining device as an adhesive form, and methods for using a heat-retaining device as an adhesive form. The following description will mainly focus on components that differ from those in the embodiments described above, while similar components will be denoted by the same reference numerals and their descriptions will be omitted. For components not specifically described in this embodiment, the descriptions of the components described above will apply as appropriate.

[0100] Figure 9 shows one embodiment in which the heating device 1 is attached to the body. The heating device 1 of this embodiment preferably comprises a main body 2 having a surface sheet 5 that forms the skin-facing surface during use and a back sheet 6 that forms the non-skin-facing surface during use, and a heating element 3 provided in the main body 2. It is preferable that the heating element 3 is held between the surface sheet 5 and the back sheet 6 that constitute the main body 2. It is also preferable that the heating element 3 is housed in a breathable packaging material 35 and held between the surface sheet 5 and the back sheet 6 that constitute the main body 2.

[0101] In this embodiment, it is preferable that the surface sheet 5 constituting the skin-facing surface has an adhesive portion 51 provided on a part or the entirety of its outer surface. The adhesive portion 51 is for holding the heating device 1 in place at the location where the heat and steam generated from the heating device 1 are to be applied. By providing the adhesive portion 51, the heating device 1 can be attached directly to the user's skin or to the user's clothing, allowing it to be easily held in place on a predetermined area that is to be heated. Furthermore, in order to allow the adhesive portion to exhibit its adhesive properties at a desired timing, a substrate such as a film covering the adhesive portion may be provided.

[0102] Further embodiments of the heating device 1 will be described below with reference to Figure 10. Figure 10 shows a heating device having the form of a so-called face mask as one embodiment of the heating device. In other words, this disclosure includes the use of a heating device as a face mask, as well as methods for using a heating device as a face mask. In the following description, we will mainly describe the components that differ from the embodiments described above, and the same components will be denoted by the same reference numerals and their descriptions will be omitted. For components that are not specifically described in this embodiment, the descriptions of the components described above will apply as appropriate.

[0103] Figure 10 shows one 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 at least one of the user's mouth and nose when in use, and a heating element 3 provided in the main body 2. In addition, it is preferable that the heating device 1 of this embodiment is provided with a pair of ear loops 4 at both the left and right ends of the main body 2. The ear loops make it possible to maintain coverage of at least one of the user's mouth and nose. In this embodiment, the ear loop portion 4 is made of a sheet material. Preferably, an insertion portion 4A is formed in the central area of ​​the ear hook portion 4. It is preferable that the heating element 3 is held between the surface sheet 5 and the back sheet 6 that constitute the main body 2. It is also preferable that the heating element 3 is housed in a breathable packaging material 35 and held between the surface sheet 5 and the back sheet 6 that constitute the main body 2.

[0104] In this embodiment, the heating device 1 preferably has a folding line 15 at a position corresponding to the bridge of the user's nose, as shown in Figure 10. In this embodiment, the folding line 15 is provided in the lateral central area of ​​the main body 2 of the heating device 1. With this configuration, when the face mask-shaped heating device 1 is used, the folding line 15 acts as a flexible axis, allowing the surface sheet 5 to adhere closely to the convex shape of the nose. This reduces the gap between the heating device 1 and the object to be heated, thereby enhancing the heating and humidifying effect. Alternatively, depending on the intended use, a flat-shaped heating device 1 without folding lines 15 may be used. In this embodiment, the heating device 1 can be used by holding it on the ear using the ear loop portion 4.

[0105] Further embodiments of the heating device 1 will be described below with reference to Figure 11. Figure 11 shows a heating device having a so-called cup shape as one embodiment of the heating device. In other words, this disclosure includes the use of a heating device in the form of a cup, as well as methods for using a heating device in the form of a cup. In the following description, we will mainly describe the components that differ from the embodiments described above, and the same components will be denoted by the same reference numerals and their descriptions will be omitted. For components that are not specifically described in this embodiment, the descriptions of the components described above will apply as appropriate.

[0106] Figure 11 shows one 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 user's mouth and nose when in use, and a heating element 3 provided in the main body 2. The heating device 1 of this embodiment may or may not have ear loops that can maintain coverage of at least one of the user's mouth and nose, depending on its intended use.

[0107] In this embodiment, the heating device 1 preferably has a main body 2 which is composed of a first panel portion 21 and a second panel portion 22 having substantially the same shape as the first panel portion 21, as shown in Figure 11. In this embodiment, both panel portions 21 and 22 are formed in a fan shape, and it is preferable that the tapered portions of both panel portions 21 and 22 are continuous. Preferably, both the first panel section 21 and the second panel section 22 are composed of a continuous surface sheet 5 and a continuous back sheet 6, and the heating element 3 is held between the surface sheet 5 and the back sheet 6. It is also preferable that the heating element 3 is housed in a breathable packaging material 35 and held between the surface sheet 5 and the back sheet 6 that constitute the main body 2.

[0108] In this embodiment, it is preferable that the heating device 1 has a boundary line D at the continuous portion between the first panel portion 21 and the second panel portion 22, which serves as a flexible axis for bending the main body portion 2. In this embodiment, it is preferable that the first panel portion 21 and the second panel portion 22 have shapes that are symmetrical with respect to the boundary line D. In this embodiment, the heating device 1 is folded so that the surface sheets 5 face each other with respect to 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 together. In both panel sections 21 and 22, the third side edge 21C of the first panel section 21 and the third side edge 22C of the second panel section 22, which are located on the outside, are not joined together, forming a cup-shaped opening. Preferably, this opening is large enough to cover the user's nose and mouth. This creates a bottomed, cylindrical, cup-shaped heating device with the boundary line D and its vicinity as its base. The outer surface of this cup-shaped heating device is formed by the back sheet 6, and the inner surface is formed by the front sheet 5.

[0109] The cup-shaped heating device of this embodiment does not have ear loops. In this case, it is preferable that the bottomed cylindrical cup-shaped heating device has a body that can be grasped by hand. In other words, it is preferable that the cup-shaped heating device is configured so that the body can be grasped by hand. The cup-shaped heating device can be used by, for example, grasping the main body with one's hand and holding the opening of the cup-shaped heating device near the user's nose and mouth.

[0110] The various sheet materials that can be used for the ear loops, surface sheet and back sheet, as well as the base sheet, packaging material and moisture-permeable sheet, should be determined independently and appropriately, 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. Examples of sheet materials include nonwoven fabrics, woven fabrics, paper or other fiber sheets, resin foam sheets, metal sheets, or combinations thereof. The sheet material may be a single structure consisting of only one sheet material, whether single-layered or multi-layered, or it may be a laminated structure made by stacking two or more types of sheet materials.

[0111] Meltblown nonwoven fabric is a suitable material for sheet materials with high breathability and moisture permeability. For sheet materials used to improve texture, air-through nonwoven fabrics and thermal-bonded nonwoven fabrics are preferably used. As sheet materials used to provide elasticity, for example, air-through nonwoven fabrics, spunbond nonwoven fabrics, and thermal-bond nonwoven fabrics containing synthetic fibers such as polyethylene terephthalate, polyethylene, and polypropylene are used. Suitable sheet materials used to impart strength include spunbond nonwoven fabrics, spunlace nonwoven fabrics, needle-punched nonwoven fabrics, and chemical-bonded nonwoven fabrics. In addition to, or as an alternative to, the nonwoven fabric described above, a nonwoven fabric surface-treated with silicone or a surfactant may be used, or a foamed sheet made from thermoplastic resins such as polyethylene or polyurethane may be used. Furthermore, these sheet materials can be made to exhibit desired properties by mixing multiple fibers with different raw materials, fiber diameters, and degrees of crimp, or by combining multiple sheet materials. The ear loops, surface sheet and back sheet, as well as the base sheet, packaging material and moisture-permeable sheet, may each be a single structure consisting of only one sheet material, whether single-layer or multi-layer, or a laminated structure made by layering two or more sheet materials.

[0112] As mentioned above, it is preferable to use a fiber sheet for the surface sheet. From the viewpoint of improving the manufacturing efficiency of heating devices, at least one of needle-punched nonwoven fabrics, air-through nonwoven fabrics, spunbond nonwoven fabrics, and chemical-bonded nonwoven fabrics can preferably be used.

[0113] When using nonwoven fabric or other fiber sheets as the surface and backing sheets, it is preferable that both the surface and backing sheets have breathability. "Breathability" means that the air permeability measured according to JIS P8117:2009 is 10,000 seconds / 100 mL or less. The air permeability measured according to JIS P8117 is 6.42 cm³ per 100 mL of air at normal temperature and pressure. 2 It is defined as the time it takes to pass through the area.

[0114] More specifically, the air permeability of the surface sheet and the back sheet is preferably 0.01 seconds / 100 mL or more, and more preferably 0.03 seconds / 100 mL or more, independently of each other. Air permeability is measured according to JIS P8117:2009. Low air permeability means that air passes through quickly, and therefore indicates high breathability. By using a surface sheet with such breathability, it is possible to efficiently impart heat or steam to the object to be heated, and to efficiently control the oxidation reaction of the oxidizable metal, thereby obtaining a heating device with desired heating characteristics.

[0115] In a packaging material that is breathable, and the packaging material comprises a first sheet material that is breathable and a second sheet material that is less breathable than the first sheet material, the air permeability of the first sheet material constituting the packaging material is preferably 20 seconds / 100 mL or more, more preferably 30 seconds / 100 mL or more, and even more preferably 40 seconds / 100 mL or more. Furthermore, the air permeability of the first sheet material is preferably 25,000 seconds / 100 mL or less, more preferably 15,000 seconds / 100 mL or less, and even more preferably 10,000 seconds / 100 mL or less.

[0116] The first sheet material having the aforementioned degree of breathability can be, for example, a resin film with multiple 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 degree of breathability can be appropriately changed by adjusting the degree of stretching. Sheets applicable to the first sheet material are disclosed, for example, in EP1939240 A1.

[0117] In a packaging material that is breathable, and the packaging material comprises a first sheet material that is breathable and a second sheet material that is less breathable than the first sheet material, the air permeability of the second sheet material constituting the packaging material is preferably 10,000 seconds / 100 mL or more, more preferably 25,000 seconds / 100 mL or more, and even more preferably non-breathable from the viewpoint of exhibiting sufficient and appropriate heat generation characteristics and adequately supplying water vapor to the object to be heated. "Non-permeable" means that the air permeability measured according to JIS P8117:2009 is 80,000 seconds / 100 mL or more. As the second sheet material having the aforementioned degree of breathability, for example, a resin film with fewer through-holes than the first sheet material, or a resin film without through-holes, can be used.

[0118] When a breathable packaging material is provided, and the packaging material comprises a first sheet material that is breathable and a second sheet material that is less breathable than the first sheet material, the moisture permeability of the first sheet material, as measured according to JIS Z0208, is preferably 480 g / m 2 24 hours or more, more preferably 720 g / (m 2 24 hours or more, more preferably 960 g / (m 2 • 24 hours or longer. Furthermore, the moisture permeability of the first sheet material, as measured according to JIS Z0208, is preferably 5000 g / (m²). 2 • 24 hours) or less, more preferably 4750 g / (m 2 • 24 hours) or less, more preferably 4500 g / m 2 • Less than 24 hours Furthermore, the moisture permeability of the second sheet material, as measured according to JIS Z0208, is preferably 480 g / (m²). 2 • 24 hours or less, more preferably 240 g / (m 2 • 24h) or less, more preferably 0g / (m 2 (24 hours) By independently setting the moisture permeability of the first and second sheet materials to the aforementioned ranges, sufficient and appropriate heat generation characteristics can be achieved, and water vapor can be adequately supplied to the object to be heated. For each sheet material that satisfies these moisture permeability requirements, for example, the same sheet material described above in the section on air permeability can be used.

[0119] When using a fiber sheet as the surface sheet, the basis weight of the surface sheet is 10 g / m². 2 Preferably, it is 30 g / m 2 It is more preferable that the amount be greater than or equal to 50 g / m 2 It is even more preferable that the above conditions are met. The basis weight of the surface sheet is 200 g / m². 2 Preferably, it is 130 g / m². 2 It is more preferable that the following conditions apply: 100g / m 2 It is even more preferable that the above conditions are met.

[0120] Furthermore, when using a fiber sheet as the backing sheet, it is preferable that the basis weight of the backing sheet be smaller than that of the fronting sheet, from the viewpoint of improving heat retention and printability. In detail, the basis weight of the backing sheet is 10 g / m². 2 Preferably, it is 20 g / m 2 It is even more preferable that the above conditions are met. The basis weight of the backing sheet is 100g / m². 2 Preferably, it is 80 g / m 2 The following is even more preferable: If the surface sheet and back sheet have a laminated structure, the total basis weight of the sheets should be within the range described above.

[0121] In the context of breathable sheets, "breathability" refers to a moisture permeability of 2000 g / m³ of the sheet, as measured according to JIS Z0208. 2 This refers to a period of 24 hours or more. Specifically, the moisture-permeable sheet has a moisture permeability of 2000 g / m² as measured according to JIS Z0208. 2 24 hours or more, more preferably 2500 g / m 2 24 hours or more, more preferably 3000 g / (m 2 • 24 hours or longer. The above-mentioned moisture-permeable sheet can be suitably used as a moisture-permeable sheet in a water-absorbent resin layer. When multiple moisture-permeable sheets are used, the moisture permeability values ​​of each sheet may be the same or different.

[0122] If the heating device has ear loops, the shape of the ear loops is not limited to the sheet-like members shown in Figures 4 and 5, as long as the main body can be fixed to both of the user's eyes. For example, instead of ear loops made of sheet material, ear loops made of string-like material or ear loops made of thread-like or strip-like material may be used. From the viewpoint of improving the fit of the heating device, it is preferable to use an elastic material such as rubber to make the ear loop portion 4 stretchable.

[0123] Although the heating elements in the heating devices of the embodiments shown in Figures 4, 9, 10, and 11 were described as being in a configuration where two heating elements are held spaced apart, the configuration of the heating elements is not particularly limited as long as it is possible to impart a feeling of warmth to the object to be heated and its surroundings. For example, one heating element having a shape and size that can cover the object to be heated and its surroundings may be held between the front sheet and the back sheet, or three or more heating elements may be held between the front sheet and the back sheet.

[0124] Furthermore, although the heating elements shown in Figures 5 and 6 are only partially fixed in the lateral central region of the heating device, the configuration is not limited to this. For example, the heating element and the backing sheet may be continuously or intermittently joined with adhesive in the central region and regions other than the central region in the lateral direction, or the entire surface of the backing sheet where the heating element is placed may be joined by applying adhesive.

[0125] Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments.

[0126] With regard to the embodiments of the present disclosure described above, the following heating device is further disclosed. <1> The heating element comprises powder of an oxidizable metal, powder of a carbon material, water, and powder of a porous material excluding the oxidizable metal and the carbon material. The heating element is a sheet-like material. The heating element is a heating device in which the ratio of the mass content of water to the mass content of the powder of the oxidizable metal multiplied by 100 [100 × (water / powder of the oxidizable metal)] is between 30 and 270. <2> The heating element comprises powder of an oxidizable metal, powder of a carbon material, water, and powder of a porous material excluding the oxidizable metal and the carbon material. The heating element is a sheet-like material. The heating element is a heating device in which the ratio of the mass content of the porous material powder to the mass content of the oxidizable metal powder multiplied by 100 [100 × (porous material powder / oxidizable metal powder)] is between 1 and 25. <3> The heating element comprises powder of an oxidizable metal, powder of a carbon material, water, and powder of a porous material excluding the oxidizable metal and the carbon material. The heating element is a sheet-like material. The heating element is a heating device in which the value obtained by multiplying the ratio of the mass content of the porous material powder to the mass content of the water by 100 [100 × (porous material powder / water)] is 1 or more and 30 or less.

[0127] <4> The heating element has a value obtained by multiplying the ratio of the content mass of the porous material powder to the content mass of the oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] which is preferably 1 or more, more preferably 3 or more, and even more preferably 5 or more. <1> ~ <3> A heating device as described in any one of the following. <5> The heating element has a value obtained by multiplying the ratio of the content mass of the porous material powder to the content mass of the oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] which is preferably 25 or less, more preferably 20 or less, and even more preferably 15 or less. <1> ~ <4> A heating device as described in any one of the following. <6> The heating element has a value obtained by multiplying the ratio of the mass content of the porous material powder to the mass content of the water by 100 [100 × (porous material powder / water)] which is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. <1> ~ <5> A heating device as described in any one of the following. <7> The heating element has a value obtained by multiplying the ratio of the mass content of the porous material powder to the mass content of the water by 100 [100 × (porous material powder / water)] which is preferably 30 or less, more preferably 20 or less, and even more preferably 15 or less. <1> ~ <6> A heating device as described in any one of the following.

[0128] <8> The heating element is housed in a breathable packaging material. A layer containing water-absorbent resin powder is disposed between the heating element and the packaging material. <1> ~ <7> A heating device as described in any one of the following. <9> The water-absorbing resin powder is sandwiched between two moisture-permeable sheets to form the layer, <8> The heating device described above. <10> The moisture permeability of the moisture-permeable sheet, measured according to JIS Z0208, is preferably 2000 g / m², independently of each other. 2 24 hours or more, more preferably 2500 g / m 2 24 hours or more, more preferably 3000 g / (m 2 • 24 hours or more, as stated above <9> The heating device described above.

[0129] <11> Preferably, one side of the packaging material is made up of a first sheet material that is breathable. Preferably, the packaging material has the other side composed of a second sheet material which has lower breathability than the first sheet material. <8> ~ <10> A heating device as described in any one of the following. <12> It is even more preferable that the layer containing the water-absorbent resin powder and the first sheet material in the packaging material are arranged to face each other. <11> The heating device described above.

[0130] <13> The heating element is a sheet-like material consisting of a base sheet and a layer of a heating composition provided on one surface thereof. The heating element has a value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100 [100 × (water / powder of the oxidizable metal)] of 80 to 270. The heat-generating composition layer is obtained from a paste containing the powder of the oxidizable metal, the powder of the carbon material, the powder of the porous material, and water. <1> ~ <12> A heating device as described in any one of the items. <14> The heating element has a value [100 × (water / powder of oxidizable metal)] which is obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100, preferably 80 or more, more preferably 90 or more, and even more preferably 110 or more. <13> The heating device described above. <15> The heating element has a value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100 [100 × (water / powder of the oxidizable metal)] which is preferably 270 or less, more preferably 220 or less, and even more preferably 160 or less. <13> or <14> The heating device described above. <16> The heating element consists of a base sheet and a layer of a heating composition provided on one surface thereof. The heat-generating composition layer is obtained from a paste containing the powder of the oxidizable metal, the powder of the carbon material, the powder of the porous material, and water. It further comprises a layer containing water-absorbent resin powder, The heat-generating composition is disposed between the base sheet and the layer containing the water-absorbent resin powder. <1> ~ <15> A heating device as described in any one of the following. <17> The heating element consists of a base sheet and a layer of a heating composition provided on one surface thereof. The heat-generating composition layer is obtained from a paste containing the powder of the oxidizable metal, the powder of the carbon material, the powder of the porous material, and water. It further comprises a layer containing water-absorbent resin powder, The layer containing the water-absorbent resin powder is arranged as the base sheet, <1> ~ <16> A heating device as described in any one of the following.

[0131] <18> The heating element is a sheet-like material obtained by mixing the powder of the oxidizable metal, the powder of the carbon material, the powder of the porous material, water, and a fibrous material. The heating element has a value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100 [100 × (water / powder of the oxidizable metal)] which is 30 or more and 80 or less. <1> ~ <12> A heating device as described in any one of the following. <19> The fiber material preferably includes at least one of wood pulp, cotton, and polyester. <18> The heating device described above. <20> The heating element has a value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100 [100 × (water / powder of the oxidizable metal)] which is preferably 30 or more, more preferably 35 or more, and even more preferably 40 or more. <18> or <19> The heating device described above. <21> The heating element has a value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100 [100 × (water / powder of the oxidizable metal)] which is preferably 80 or less, more preferably 70 or less, and even more preferably 60 or less. <18> ~ <20> A heating device as described in any one of the following.

[0132] <22> The porous material has a pore diameter of 0.01 μm or more and 5 μm or less. <1> ~ <21> A heating device as described in any one of the following. <23> The pore diameter of the porous material is preferably 0.01 μm or more, more preferably 0.02 μm or more, even more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and even more preferably 0.15 μm or more. <1> ~ <22> A heating device as described in any one of the following. <24> The pore diameter of the porous material is preferably 5 μm or less, more preferably 1 μm or less, even more preferably 0.8 μm or less, even more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. <1> ~ <23> A heating device as described in any one of the following. <25> The porous material consists of a silicon-containing inorganic compound, <1> ~ <24> A heating device as described in any one of the following.

[0133] <26> The porous material is made of calcium silicate, <1> ~ <25> A heating device as described in any one of the following. <27> The pore diameter of the calcium silicate is 0.02 μm or more and 0.8 μm or less, <26> The heating device described above. <28> The pore diameter of the calcium silicate is more preferably 0.02 μm or more, even more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and even more preferably 0.15 μm or more. <26> or <27> The heating device described above. <29> The pore diameter of the calcium silicate is more preferably 0.8 μm or less, even more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. <26> ~ <28> A heating device as described in any one of the following.

[0134] <30> The calcium silicate is one or more of the following: gyrolite compounds, urastonite compounds, tobermorite compounds, and calcium silicate hydrate compounds. <26> ~ <29> A heating device as described in any one of the following. <31> The porous material is more preferably one or more of gyrolite, xonotlite, and tobermorite. The porous material is more preferably gyrolite. <1> ~ <30> A heating device as described in any one of the following.

[0135] <32> The oil absorption capacity of the porous material powder, as measured according to the provisions of JIS K5010-13-2, is preferably 300 mL / 100 g or more, more preferably 350 mL / 100 g or more, and even more preferably 400 mL / 100 g or more. <1> ~ <31> A heating device as described in any one of the following. <33> The amount of oil absorbed by the porous material powder, as measured according to the provisions of JIS K5010-13-2, is preferably 900 mL / 100 g or less, more preferably 800 mL / 100 g or less, and even more preferably 700 mL / 100 g or less. <1> ~ <32> A heating device as described in any one of the following. <34> The particle size of the particles constituting the porous material powder is preferably 1 μm or larger, and more preferably 10 μm or larger. The particle size of the particles constituting the porous material powder is preferably 200 μm or less, and more preferably 100 μm or less. <1> ~ <33> A heating device as described in any one of the following.

[0136] <35> The oxidizable metal powder is preferably iron powder. It is more preferable that one or more types are selected from reduced iron powder and atomized iron powder. <1> ~ <34> A heating device as described in any one of the following. <36> The aforementioned oxidizable metal powder is composed of particles having pores on its surface. Preferably, the pore diameter of the particles constituting the oxidizable metal powder is smaller than the pore diameter of the porous material powder. <1> ~ <35> A heating device as described in any one of the following. <37> The pore diameter of the particles constituting the powder of the oxidizable metal is preferably 0.001 μm or more, more preferably 0.003 μm or more, and even more preferably 0.006 μm or more. The pore diameter of the particles constituting the powder of the oxidizable metal is preferably 0.07 μm or less, more preferably 0.05 μm or less, and even more preferably 0.01 μm or less. <36> The heating device described above. <38> The particle size of the particles constituting the oxidizable metal powder is preferably 1 μm or larger, and more preferably 10 μm or larger. The particle size of the particles constituting the powder of the oxidizable metal is preferably 200 μm or less, and more preferably 100 μm or less. <1> ~ <37> A heating device as described in any one of the following. <39> The heating device according to any one of <1> to <38>, wherein the powder of the carbon material is preferably activated carbon powder. <40> 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 <39>, 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. <41> The heating device according to any one of <1> to <40>, wherein the heating element preferably contains an electrolyte.

[0137] <42> A main body portion having a shape that covers the object to be heated during use, and the heating element provided in the main body portion. The main body portion includes a front surface sheet located on the side closer to the object to be heated and a back surface sheet located on the side farther from the object to be heated. The heating device according to any one of <1> to <41>, wherein the heating element is held between the front surface sheet and the back surface sheet. <43> A main body portion having a shape that covers both eyes of the user during use, the heating element provided in the main body portion, and a pair of ear hooks attached to the main body portion and capable of maintaining the state of covering both eyes of the user by the main body portion. The main body portion includes a front surface sheet located on the side closer to the user's skin and a back surface sheet located on the side farther from the user's skin. The heating device according to any one of <1> to <42>, wherein the heating element is held between the front surface sheet and the back surface sheet. <44> For the heating device according to <42>, it is preferable that an adhesive portion is provided in a part or the whole of the outer surface of the front surface sheet.

[0138] <45> The system comprises a main body having a shape that covers at least one of the user's mouth and nose when in use, and the heating element provided in the main body. The main body comprises a front sheet located on the side closer to the user's skin and a back sheet located on the side further away from the user's skin. The heating element is held between the surface sheet and the back sheet. <1> ~ <42> A heating device as described in any one of the following. <46> The main body further comprises a pair of ear hooks that are attached to the main body and capable of maintaining the state in which the main body covers at least one of the user's mouth and nose, <45> The heating device described above. <47> It does not include a pair of ear hooks that are attached to the main body and capable of maintaining the state in which at least one of the user's mouth and nose is covered by the main body, When using the aforementioned heating device, the main body is configured to be grasped by hand, <45> The heating device described above.

[0139] <48> The air permeability of the surface sheet, as measured according to JIS P8117, is preferably 0.01 seconds / 100 mL or more, and more preferably 0.03 seconds / 100 mL or more. The air permeability of the back sheet, as measured in accordance with JIS P8117, is preferably 0.01 seconds / 100 mL or more, and more preferably 0.03 seconds / 100 mL or more. <42> ~ <47> A heating device as described in any one of the following. <49> The basis weight of the surface sheet is 10 g / m². 2 Preferably, it is 30 g / m 2 It is more preferable that the amount be greater than or equal to 50 g / m 2 It is even more preferable that the above conditions are met. The basis weight of the surface sheet is 200 g / m². 2 Preferably, it is 130 g / m². 2 It is more preferable that the following conditions apply: 100g / m 2 More preferably the above, <42> ~ <48> A heating device as described in any one of the following. <50> The basis weight of the back sheet is preferably smaller than the basis weight of the front sheet. The basis weight of the aforementioned backing sheet is 10 g / m². 2 Preferably, it is 20 g / m 2 It is even more preferable that the above conditions are met. The basis weight of the backing sheet is 1 g / m². 2 Preferably, it is 80 g / m 2 More preferably the following, <42> ~ <49> A heating device as described in any one of the following.

[0140] <51> Preferably, the heating element is housed within a breathable packaging material and held between the surface sheet and the back sheet. <42> ~ <50> A heating device as described in any one of the following. <52> Preferably, one side of the packaging material is made up of a first sheet material that is breathable. Preferably, the other side of the packaging material is composed of a second sheet material which has lower breathability than the first sheet material. The first sheet material is preferably arranged to face the surface sheet. The second sheet material is preferably arranged to face the back sheet. <51> The heating device described above.

[0141] <53> The air permeability of the first sheet material, measured according to JIS P8117, is preferably 20 seconds / 100 mL or more, more preferably 30 seconds / 100 mL or more, and even more preferably 40 seconds / 100 mL or more. <11> , <12> , <52> A heating device as described in any one of the following. <54> The air permeability of the first sheet material, as measured according to JIS P8117, is preferably 25,000 seconds / 100 mL or less, more preferably 15,000 seconds / 100 mL or less, and even more preferably 10,000 seconds / 100 mL or less. <11> , <12> , <52> , <53> A heating device as described in any one of the following. <55> The air permeability of the second sheet material, as measured according to JIS P8117, is preferably 10,000 seconds / 100 mL or more, more preferably 25,000 seconds / 100 mL or more, and even more preferably non-air permeable. <11> , <12> , <52> ~ <54> A heating device as described in any one of the following.

[0142] <56> The moisture permeability of the first sheet material, measured according to JIS Z0208, is preferably 480 g / (m²). 2 24 hours or more, more preferably 720 g / (m 2 24 hours or more, more preferably 960 g / (m 2 • 24 hours or more, as stated above <11> , <12> , <52> ~ <55> A heating device as described in any one of the following. <57> The moisture permeability of the first sheet material, measured according to JIS Z0208, is preferably 5000 g / (m²). 2 • 24 hours) or less, more preferably 4750 g / (m 2 • 24 hours) or less, more preferably 4500 g / m 2 • Less than 24 hours, as mentioned above <11> , <12> , <52> ~ <56> A heating device as described in any one of the following. <58> The moisture permeability of the second sheet material, measured according to JIS Z0208, is preferably 480 g / (m²). 2 • 24 hours or less, more preferably 240 g / (m 2 • 24h) or less, more preferably 0g / (m 2 ·24h) the above <11> , <12> , <52> ~ <57> A heating device as described in any one of the following. <59> The heat generating device according to any one of <1> to <58> above, which has a function of generating steam with heat.

[0143] <60> Use of the heat generating device according to any one of <1> to <59> above as an eye mask. <61> Use of the heat generating device according to any one of <1> to <59> above as an attachment form. <62> Use of the heat generating device according to any one of <1> to <59> above as a face mask. <63> Use of the heat generating device according to any one of <1> to <59> above as a cup.

Example

[0144] Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. In the table, blank spaces indicate "non-containing".

[0145] 〔Examples 1 to 6 and Comparative Example 1〕 <Preparation of paint> As the powder of the oxidizable metal, iron powder (manufactured by DOWA IP Creation Co., Ltd., RKH3, particle size: 45 μm), as the powder of the carbon material, activated carbon powder (manufactured by Osaka Gas Chemical Co., Ltd., Carbolafin, particle size: 31 μm), and as the powder of the porous substance 3c, gyrolite (manufactured by Tomita Pharmaceutical Co., Ltd., product name: Flowlite R, particle size: 47 μm, pore diameter D1: 0.18 μm), which is a gyrolite-based compound of calcium silicate powder, were used. These raw materials, water, electrolytes, and thickeners were mixed at the ratios shown in Table 1 below to obtain a paste of the heat generating composition with a viscosity of 5000 mPa·s measured at 25°C with a B-type viscometer.

[0146] <Production of heat generating body> As the first moisture-permeable sheet, paper made of wood pulp (basis weight 20 g / m 2 , manufactured by Ino Paper Co., Ltd.), and particles of a water-absorbing resin (Aqualic (registered trademark) CA, manufactured by Nippon Shokubai Co., Ltd.) were applied at a basis weight of 50 g / m2 It was then scattered in layers. On top of the water-absorbent resin layer, a second moisture-permeable sheet was placed, made of wood pulp paper (basis weight 30 g / m²). 2 A sheet of absorbent resin was obtained by laminating (manufactured by Ino Paper Co., Ltd.). A thin sheet of polyethylene-laminated tissue paper (manufactured by Nitto Co., Ltd.) was used as the base sheet. The paste described above was applied to one side of the sheet by die coating while adjusting the discharge pressure to obtain a sheet-like coated material. The discharge pressure was adjusted so that the basis weight of the paste was the value shown in Table 1. Subsequently, 0.064 g of sodium chloride (Otsuka Pharmaceutical Co., Ltd., Pharmacopoeia-grade sodium chloride) was uniformly sprinkled on the paste side, and then a water-absorbent resin sheet was laminated onto 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 arranged on the heat-generating composition side of a coating-type heating element. Next, a laminate was sandwiched between a first sheet material with breathability (air permeability: 1500 seconds / 100 mL) and a second sheet material without breathability, each cut to 63 mm x 63 mm. The four sides of these sheets were then heat-sealed to obtain a heating element housed within the packaging. This configuration is illustrated in Figure 2(a). In the packaging material, the first sheet material was positioned so that its inner surface faced the outer surface of the water-absorbent resin layer. The second sheet material was positioned so that its inner surface faced the surface of the base sheet. Finally, needle-punched nonwoven fabric (basis weight 80g / m²) 2 ) consists of a surface sheet and an air-through nonwoven fabric (basis weight 30g / m²). 2 A heating element housed in packaging material is joined to a back sheet made of the material shown in Figures 4 to 7 to hold the heating element between the sheet and the back sheet, thereby obtaining an eye mask type heating device having the structure illustrated in Figures 4 to 7. The surface sheet was positioned so that its inner surface faced the outer surface of the first sheet material in the packaging. Similarly, the back sheet was positioned so that its inner surface faced the outer surface of the second sheet material in the packaging. This heating device was designed to generate steam as it heated up.

[0147] [Examples 7 and 8] A heating element and a water-absorbing resin layer, as well as an eye mask type heating device containing these, were prepared, having the same configuration as in Example 1, except that a different calcium silicate powder was used as the porous material powder from the calcium silicate powder used in Example 1. The calcium silicate powder used in Example 2 was tobermorite (manufactured by Nippon Insulation Co., Ltd., product name: tobermorite, particle size: 24 μm, pore diameter D1: 0.62 μm), a tobermorite compound, while the calcium silicate powder used in Example 3 was xonotlite (manufactured by Nippon Insulation Co., Ltd., product name: xonotlite, particle size: 47 μm, pore diameter D1: 0.46 μm), a urastonite compound.

[0148] [Examples 9-11 and Comparative Example 2] As shown in Table 1 below, a heating element, a water-absorbing resin layer, and a heating device were obtained in the same manner as in Example 1, except that the content of water, oxidizable metal, and porous material in the heating element was changed.

[0149] [Examples 12-13 and Comparative Example 3] As shown in Table 1 below, the content of water, oxidizable metal, and porous material in the heating element was changed. In addition, the first breathable sheet material that makes up the packaging was changed to one with an air permeability of 60 seconds / 100 mL or one with an air permeability of 4000 seconds / 100 mL. In the packaging material, the first sheet material was positioned so that its inner surface faced the water-absorbent resin layer. Similarly, the second sheet material was positioned so that its inner surface faced the base sheet. The surface sheet was positioned so that its inner surface faced the outer surface of the first sheet material in the packaging. Similarly, the back sheet was positioned so that its inner surface faced the outer surface of the second sheet material in the packaging. Aside from this, the heating element, the water-absorbing resin layer, and the heating device were obtained in the same manner as in Example 1.

[0150] [Example 14 and Comparative Example 4] In addition to the oxidizable metal, carbon material, porous material, and water used in Example 1, a mixture containing pulp fibers (coniferous kraft pulp, manufactured by Skeena Co., Ltd., trade name "Skeena", average fiber length: 2.1 mm) as a fibrous material was used to form an intermediate molded body by papermaking. Subsequently, an electrolyte was incorporated into the intermediate molded body to form a papermaking type heating element having the raw material ratios shown in Table 1 below. Then, a breathable sheet material with an air permeability of 2500 seconds / 100 mL was used as the packaging material, and the heating device was formed in the same manner as in Example 1. This configuration is illustrated in Figure 1(b).

[0151] [Example 15 and Comparative Example 5] Crepe paper (manufactured by Daishowa Paper Industry Co., Ltd.) was used as the first breathable sheet. A thin sheet of polyethylene-laminated tissue paper (manufactured by Nitto Co., Ltd.) was used as the base sheet. The paste described above was applied to one side of the sheet by die coating while adjusting the discharge pressure to obtain a sheet-like coated material. The discharge pressure was adjusted so that the basis weight of the paste was the value shown in Table 2. Subsequently, 0.094 g of sodium chloride (Otsuka Pharmaceutical Co., Ltd., Pharmacopoeia sodium chloride) and 0.133 g of superabsorbent polymer (sodium polyacrylate, spherical, average particle size 300 μm, Sunfresh ST-500D*, Sanyo Chemical Industries, Ltd.) were uniformly scattered on the paste side. Then, crepe paper 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 superabsorbent resin layer was arranged on the heat-generating composition side of a coating-type heating element. Next, a laminate was sandwiched between a first sheet material with breathability (air permeability: 60 seconds / 100 mL) and a second sheet material without breathability, each cut to 63 mm x 63 mm. The four sides of these sheets were then heat-sealed to obtain a heating element housed within the packaging. This configuration is illustrated in Figure 3(b). In the packaging material, the first sheet material was positioned so that its inner surface faced the outer surface of the water-absorbent resin layer. The second sheet material was positioned so that its inner surface faced the surface of the base sheet.

[0152] [Example 16 and Comparative Example 6] As the first moisture-permeable sheet, wood pulp paper (basis weight 20g / m²) is used. 2 (Manufactured by Ino Paper Co., Ltd.) on top of which are particles of superabsorbent resin (Aqualic® CA, manufactured by Nippon Shokubai Co., Ltd.) at a basis weight of 50 g / m² 2 It was then scattered in layers. On top of the water-absorbent resin layer, a second moisture-permeable sheet was placed, made of wood pulp paper (basis weight 30 g / m²). 2 A sheet of absorbent resin was obtained by laminating (Ino Paper Co., Ltd.) sheets. A thin sheet of polyethylene-laminated tissue paper (manufactured by Nitto Co., Ltd.) was used as the base sheet. The paste described above was applied to one side of the sheet by die coating while adjusting the discharge pressure to obtain a sheet-like coated material. The discharge pressure was adjusted so that the basis weight of the paste was the value shown in Table 2. Subsequently, 0.169 g of sodium chloride (Otsuka Pharmaceutical Co., Ltd., Pharmacopoeia sodium chloride) and 0.141 g of superabsorbent polymer (sodium polyacrylate, spherical, average particle size 300 μm, Sunfresh ST-500D*, Sanyo Chemical Industries, Ltd.) were uniformly scattered on the paste side. Then, a superabsorbent resin sheet was laminated onto 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 the superabsorbent resin layer was arranged on the heat-generating composition side of a coating-type heating element. Next, a laminate was sandwiched between a first sheet material with breathability (air permeability: 60 seconds / 100 mL) and a second sheet material without breathability, each cut to 63 mm x 63 mm. The four sides of these sheets were then heat-sealed to obtain a heating element housed within the packaging. This configuration is illustrated in Figure 3(c). In the packaging material, the first sheet material was positioned so that its inner surface faced the outer surface of the water-absorbent resin layer. The second sheet material was positioned so that its inner surface faced the surface of the base sheet.

[0153] [Measurement of integrated sensible heat] The total sensible heat of the heating devices in the examples and comparative examples was measured in an environment with a room temperature of 20°C and a humidity of 50%RH according to the following method. First, the oxygen-barrier bag containing the heating device to be measured was opened, and one heating element was removed from the heating device along with its packaging. Next, the first sheet material side of the packaging for the removed heating element was positioned facing outwards, and a temperature sensor was installed and fixed in the area on the second sheet material side where the heating element was located. The temperature sensor was fixed to the measurement surface using mesh material (polyester, 8 mm thick double raschel fabric) and a SUS plate (500 g perforated plate). Then, the temperature was measured over time using a measuring instrument specified in JIS S4100, connected to a temperature sensor. The measurement started when the oxygen-barrier bag was opened, and the temperature was 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 was calculated by subtracting 35°C from the measured temperature during the time when temperatures of 35°C or higher were measured. This was defined as the sensible heat accumulation (°C·10min or °C·20min). The results are shown in Tables 1 and 2 below.

[0154] [Measurement of water vapor generation] The amount of water vapor generated in the heating devices of the examples and comparative examples was measured according to the following method. Specifically, the measurement was performed using the apparatus 100 shown in Figure 12. First, the oxygen-barrier bag containing the heating device to be measured was opened, and one heating element was removed from the device along with its packaging. The first sheet material side of the packaging of the removed heating element was placed in the measurement chamber 101 with the outer surface facing outwards, and a weight 108 with a metal ball (mass 4.5g) attached was placed on top of it. In this state, dehumidified air was flowed from the bottom of the measurement chamber 101, and the difference in absolute humidity before and after air circulation in the measurement chamber 101 was determined from the temperature and humidity measured by the inlet thermometer 104 and the outlet thermometer 106. Furthermore, the amount of water vapor released from the heating element was calculated from the air flow rate measured by the inlet flowmeter 105 and the outlet flowmeter 107. The amount of water vapor generated was measured starting from the moment the heating device was removed from the oxygen-blocking bag. The total amount of water vapor measured during the first 10 minutes (mg·10min) and the total amount of water vapor measured during the next 20 minutes (mg·20min) were recorded. The results are shown in Tables 1 and 2 below.

[0155] [Table 1]

[0156] [Table 2]

[0157] As shown in Tables 1 and 2, each example of a heating device contains a porous material powder and is equipped with a heating element in which one or more of the following are specified relationships: the ratio of oxidizable metal to water, the ratio of oxidizable metal to porous material, and the ratio of oxidizable metal to porous material. Compared to the heating device of the comparative example, even though the oxidizable metal content of the heating device is the same, the integrated sensible heat is higher and the heating characteristics are superior. Consequently, the amount of water vapor generated is also significantly higher. Furthermore, even when the heating element is housed in packaging material, the heating characteristics and water vapor generation are superior regardless of the fiber sheet used. Therefore, it can be seen that the heating device of this disclosure can be manufactured at a reduced cost without increasing the content of expensive oxidizable metals, while maintaining excellent heating properties. [Industrial applicability]

[0158] This provides a heating device that offers excellent heat generation characteristics and water vapor production while keeping manufacturing costs down.

Claims

1. The heating element comprises a powder of an oxidizable metal, a powder of a carbon material, water, and a powder of a porous material consisting of a gyrolite compound. The heating element is a sheet-like material. The aforementioned heating element is The value obtained by multiplying the ratio of the mass content of water to the mass content of the oxidizable metal powder by 100 [100 × (water / oxidizable metal powder)] is between 30 and 270. The value obtained by multiplying the ratio of the content mass of the porous material powder to the content mass of the oxidizable metal powder by 100 [100 × (porous material powder / oxidizable metal powder)] is between 1 and 25. The value obtained by multiplying the ratio of the mass content of the porous material powder to the mass content of the water by 100 [100 × (porous material powder / water)] is between 1 and 30. The pore diameter of the porous material is 0.01 μm or more and 5 μm or less. A heating device wherein the oil absorption capacity of the porous material powder is 300 mL / 100 g or more and 900 mL / 100 g or less.

2. The heating element is housed in a breathable packaging material. The heating device according to claim 1, wherein a layer containing water-absorbent resin powder is disposed between the heating element and the packaging material.

3. The heating device according to claim 2, wherein the water-absorbent resin powder is sandwiched between two moisture-permeable sheets to form the layer.

4. The heating element is a sheet-like material consisting of a base sheet and a layer of a heating composition provided on one surface thereof. The heating element has a value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100 [100 × (water / powder of the oxidizable metal)] of 80 or more and 270 or less. The heating device according to any one of claims 1 to 3, wherein the layer of the heating composition is obtained from a paste containing the powder of the oxidizable metal, the powder of the carbon material, the powder of the porous material, and water.

5. The heating element is a sheet-like material obtained by mixing the powder of the oxidizable metal, the powder of the carbon material, the powder of the porous material, water, and a fibrous material. The heating element is a heating device according to any one of claims 1 to 4, wherein the value obtained by multiplying the ratio of the mass content of water to the mass content of the powder of the oxidizable metal by 100 [100 × (water / powder of the oxidizable metal)] is 30 or more and 80 or less.

6. The heating element consists of a base sheet and a layer of a heating composition provided on one surface thereof. The heat-generating composition layer is obtained from a paste containing the powder of the oxidizable metal, the powder of the carbon material, the powder of the porous material, and water. It further comprises a layer containing water-absorbent resin powder, The heating device according to any one of claims 1 to 4, wherein the heat-generating composition is disposed between the base sheet and the layer containing the water-absorbent resin powder.

7. The heating device according to any one of claims 1 to 6, wherein the pore diameter of the porous material is 0.02 μm or more and 0.8 μm or less.

8. The system comprises a main body shaped to cover both of the user's eyes when in use, a heating element provided in the main body, and a pair of ear hooks attached to the main body and capable of maintaining the covering of the user's eyes by the main body. The main body comprises a front sheet located on the side closer to the user's skin and a back sheet located on the side further away from the user's skin. The heating device according to any one of claims 1 to 7, wherein the heating element is held between the surface sheet and the back sheet.

9. A heating device according to any one of claims 1 to 8, which has the function of generating steam in conjunction with heat generation.

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