Chemical body warmer

Abstract

To provide a chemical body warmer utilizing aluminum as an oxidizable metal.SOLUTION: A chemical body warmer of the present disclosure comprises a heat-generating composition comprising an oxidizable metal, the heat-generating composition being accommodated in a container having a breathable sheet on at least one surface, wherein the oxidizable metal comprises aluminum, and the heat-generating composition further comprises zinc.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a chemical heat pack using aluminum as an oxidizable metal.

Background Art

[0002] Conventional chemical heat packs (so-called disposable heat packs) utilize a heat generation mechanism in which iron powder, which is an oxidizable metal, generates heat of oxidation by contact with oxygen, and have a structure in which a heat-generating composition containing iron powder is housed in a breathable container (inner bag) (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In conventional chemical heat packs, iron powder is widely used as an oxidizable metal. However, from the perspective of expanding the variations of chemical heat packs, the inventor considered using aluminum instead of iron powder as the oxidizable metal. However, it was found that a chemical heat pack using aluminum as the oxidizable metal does not undergo an oxidation reaction and does not generate heat in the presence of oxygen.

[0005] An object of the present disclosure is to provide a chemical heat pack using aluminum as an oxidizable metal.

Means for Solving the Problems

[0006] The inventor conducted intensive studies to solve the above problems and found that by further adding zinc to an exothermic composition containing aluminum as the metal to be oxidized, the oxidation reaction of aluminum is initiated and promoted in the presence of oxygen, and a chemical heat pack that generates heat of oxidation can be obtained. The present disclosure has been completed by further studies based on such findings.

[0007] That is, the present disclosure provides an invention in the following aspects. Item 1. A chemical heat pack in which an exothermic composition containing a metal to be oxidized is housed in a container having a breathable sheet on at least one surface, wherein the metal to be oxidized contains aluminum, and the exothermic composition further contains zinc. Item 2. The chemical heat pack according to Item 1, wherein the content of zinc is 1 to 30 parts by weight per 100 parts by weight of the aluminum. Item 3. The chemical heat pack according to Item 1 or 2, wherein the aluminum is aluminum powder, and the median diameter of the aluminum powder in the volume-based particle size distribution is 1 to 50 μm.

Effect of the Invention

[0008] Although the chemical heat pack of the present disclosure uses aluminum as the metal to be oxidized, since it contains zinc together with aluminum, the oxidation reaction of aluminum can be initiated and promoted in the presence of oxygen, and sufficient heat of oxidation is generated.

Mode for Carrying Out the Invention

[0009] In this specification, the notation X~Y regarding a numerical range indicates that it is X or more and Y or less.

[0010] The chemical warmer of the present disclosure is a chemical warmer in which an exothermic composition containing an oxidizable metal is housed in a container having a breathable sheet on at least one surface, the oxidizable metal contains aluminum, and the exothermic composition further contains zinc. Hereinafter, the chemical warmer of the present disclosure will be described in detail.

[0011] [Exothermic composition] An exothermic composition is a composition that generates heat when an oxidizable metal and oxygen come into contact with each other.

[0012] In the chemical warmer of the present disclosure, aluminum is used as the oxidizable metal. The shape of aluminum is not particularly limited, but from the viewpoint of improving the heat generation efficiency, it is preferably in powder form, granular form or fibrous form, more preferably in powder form.

[0013] When using aluminum powder, the particle size of the aluminum powder is not particularly limited, but the median diameter (D50) in the volume-based particle size distribution is usually about 1 to 50 μm, and from the viewpoint of improving the heat generation efficiency, it is preferably 1 to 45 μm, more preferably 1 to 40 μm, still more preferably 1 to 35 μm, and particularly preferably 1 to 30 μm. In the present invention, the median diameter in the volume-based particle size distribution is a value obtained from the volume-based particle size distribution obtained by dry measurement using the laser diffraction / scattering method.

[0014] In the chemical chiro of the present disclosure, it is preferable to use only aluminum as the metal to be oxidized, but aluminum and a metal to be oxidized other than aluminum may be used in combination. The metal to be oxidized other than aluminum is not particularly limited as long as it can generate heat by oxidation. For example, metals such as iron (reduced iron, cast iron, atomized iron, electrolytic iron), manganese, magnesium, and calcium can be mentioned. The exemplified metals to be oxidized may be used alone or in combination of two or more. When aluminum and a metal to be oxidized other than aluminum are used in combination, the content of aluminum is preferably 70% by weight or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 95% by weight or more based on the total amount of the metals to be oxidized.

[0015] The total content of the metal to be oxidized in the exothermic composition is appropriately set according to the exothermic characteristics to be imparted. For example, it is about 15 to 80% by weight. From the viewpoint of improving the exothermic efficiency, it is preferably 20 to 70% by weight, more preferably 25 to 60% by weight.

[0016] The exothermic composition contains zinc together with aluminum. Zinc is considered to have a function of initiating and promoting the oxidation reaction of aluminum in the presence of oxygen. The shape of zinc is not particularly limited, but from the viewpoint of further promoting the oxidation reaction of aluminum, it is preferably in powder form, granular form or fibrous form, and more preferably in powder form. When zinc powder is used, the particle size of the zinc powder is not particularly limited, but from the viewpoint of further promoting the oxidation reaction of aluminum, it is preferably one that passes through a mesh with an opening of 200 μm, more preferably one that passes through a mesh with an opening of 150 μm, still more preferably one that passes through a mesh with an opening of 100 μm, and even more preferably one that passes through a mesh with an opening of 75 μm.

[0017] The content of zinc in the exothermic composition is appropriately set according to the content of aluminum. For example, it is about 0.1 to 15% by weight, and from the viewpoint of further promoting the oxidation reaction of aluminum and improving the exothermic efficiency, it is preferably 0.3 to 10% by weight, more preferably 0.5 to 7% by weight.

[0018] In the exothermic composition, the content of zinc is usually 0.5 to 40 parts by weight per 100 parts by weight of aluminum. From the viewpoint of further promoting the oxidation reaction of aluminum and improving the exothermic efficiency, it is preferably 1 to 30 parts by weight, more preferably 1.5 to 25 parts by weight, and still more preferably 2 to 20 parts by weight.

[0019] The exothermic composition may contain an oxidation promoter as required. The oxidation promoter serves to hold oxygen and supply oxygen to the metal to be oxidized. The type of the oxidation promoter is not particularly limited as long as it can hold oxygen and supply oxygen to the metal to be oxidized. For example, carbon materials such as activated carbon, carbon black, acetylene black, bamboo charcoal, charcoal, coffee husk charcoal, graphite, coal, coconut shell charcoal, calendar blue charcoal, peat, lignite, etc. can be mentioned. The exemplified oxidation promoters may be used alone or in combination of two or more. Among the exemplified oxidation promoters, activated carbon, carbon black, bamboo charcoal, charcoal, and coffee husk charcoal are preferred, and activated carbon is more preferred. Also, the shape of the oxidation promoter is not particularly limited, but from the viewpoint of improving the exothermic efficiency, it is preferably powdery, granular or fibrous, and more preferably powdery. The content of the oxidation promoter in the exothermic composition is appropriately set according to the exothermic characteristics to be imparted, etc. For example, it is about 1 to 30% by weight, and from the viewpoint of improving the exothermic efficiency, it is preferably 3 to 20% by weight, more preferably 7 to 15% by weight.

[0020] The exothermic composition may contain water as required. Water plays a role in oxidizing the metal to be oxidized together with oxygen. Any of distilled water, ion-exchanged water, pure water, ultrapure water, tap water, industrial water, etc. may be used for water. The water content in the exothermic composition is appropriately set according to the exothermic characteristics to be imparted. For example, it is about 5 to 55% by weight, preferably 10 to 50% by weight, more preferably 20 to 40% by weight from the viewpoint of improving the exothermic efficiency.

[0021] The exothermic composition may contain water-soluble salts as required. When water-soluble salts are included, it becomes possible to promote the oxidation of the metal to be oxidized. The types of water-soluble salts are not particularly limited. For example, sulfates, hydrogen carbonates, chlorides or hydroxides of alkali metals (such as sodium, potassium, etc.), alkaline earth metals (such as calcium, magnesium, etc.), or heavy metals (such as iron, copper, aluminum, zinc, nickel, silver, barium, etc.) can be mentioned. Among the exemplified water-soluble salts, from the viewpoints of conductivity, chemical stability, etc., chlorides such as sodium chloride, potassium chloride, calcium chloride, magnesium chloride, iron (II, III) chloride, etc. are preferable, and sodium chloride is more preferable. The exemplified water-soluble salts may be used alone or in combination of two or more. The content of water-soluble salts in the exothermic composition is appropriately set according to the exothermic characteristics to be imparted. For example, it is about 0.1 to 10% by weight, preferably 0.5 to 7% by weight, more preferably 1 to 5% by weight from the viewpoint of improving the exothermic efficiency.

[0022] The exothermic composition may optionally contain a water retention agent. The water retention agent serves to retain water and supply water to the oxidation reaction site. The type of the water retention agent is not particularly limited. For example, inorganic porous substances such as vermiculite, perlite, calcium silicate, magnesium silicate, kaolin, talc, smectite, mica, bentonite, calcium carbonate, silica gel, alumina, zeolite, silicon dioxide, and diatomaceous earth; organic substances such as pulp, wood powder, cotton, starches, and celluloses; water-absorbing resins such as polyacrylic acid-based resins, polysulfonic acid-based resins, maleic anhydride-based resins, polyacrylamide-based resins, polyvinyl alcohol-based resins, polyethylene oxide-based resins, polyaspartic acid-based resins, polyglutamic acid-based resins, and polyalginate-based resins can be mentioned. The exemplified water retention agents may be used alone or in combination of two or more. Among the exemplified water retention agents, vermiculite, polyacrylic acid-based resins, wood powder, and pulp are preferable, and vermiculite and polyacrylic acid-based resins are more preferable. The content of the water retention agent in the exothermic composition is appropriately set according to the exothermic characteristics to be imparted. For example, it is about 1 to 20% by weight, and from the viewpoint of improving the exothermic efficiency, it is preferably 3 to 15% by weight, more preferably 4 to 10% by weight.

[0023] The exothermic composition may further optionally contain other additives such as a sequestering agent, a fragrance, a thickener, an excipient, a surfactant, and a hydrogen generation inhibitor.

[0024] The exothermic composition can be prepared by mixing the aforementioned components in a predetermined amount. The preparation of the exothermic composition may be carried out in the presence of oxygen, but it is preferably carried out under reduced pressure or in an inert gas atmosphere.

[0025] [Container] In the chemical warmer of the present disclosure, the container that houses the exothermic composition has a breathable sheet on at least one surface in order to supply oxygen and water vapor to the exothermic composition during use.

[0026] The material of the breathable sheet is not particularly limited, but it is preferably formed by at least a breathable resin layer (a resin layer having pores). From the viewpoint of improving the usability, a laminated sheet of a breathable resin layer and a fiber base material is more preferable. For the laminated sheet of the breathable resin layer and the fiber base material, the breathable resin layer and the fiber base material may be laminated in this order from the inside to the outside of the container.

[0027] The constituent resin of the breathable resin layer is not particularly limited. For example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polyacrylonitrile, ethylene-vinyl alcohol copolymer, polyamide, polyurethane, polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polycarbonate, etc. may be mentioned. Among the resins exemplified above, polyethylene, polypropylene, and ethylene-vinyl acetate copolymer are preferable. The constituent resin may be used alone or in combination of two or more.

[0028] Also, the breathable resin layer may be a resin film provided with pores for ensuring breathability. The shape, size, and number of pores provided in the resin film may be appropriately set according to the breathability and moisture permeability to be provided in the container.

[0029] Specific examples of the fiber base material used for the breathable sheet include non-woven fabric and woven fabric. From the viewpoint of usability and the like, non-woven fabric is preferably used. The material of the fiber base material is not particularly limited. For example, synthetic fibers such as polyethylene terephthalate, polybutylene terephthalate, nylon, polypropylene, polyethylene, vinylon, rayon, acrylic, acetate, and polyvinyl chloride; natural fibers such as cotton, hemp, silk, and paper; and mixed fibers thereof may be mentioned. Among the materials exemplified above, from the viewpoint of enhancing the usability, polyethylene terephthalate, nylon, and polypropylene are preferable, and polyethylene terephthalate and nylon are more preferable. The materials may be used alone or in combination of two or more.

[0030] The lamination of the breathable resin layer and the fiber substrate can be carried out by known lamination methods such as dry lamination, extrusion lamination, and thermal lamination.

[0031] Regarding the thickness of the breathable sheet, it may be appropriately set according to the layer structure of the breathable sheet and the like. For example, it is about 15 to 150 μm.

[0032] Regarding the basis weight of the breathable sheet, it may be appropriately set according to the layer structure of the breathable sheet and the like. For example, it is about 1 to 100 g / m 2 degree.

[0033] The container only needs to have the breathable sheet on at least one surface. Preferred examples of the container include a container in which the peripheral edges of two of the breathable sheets are bonded together, and a container in which the peripheral edges of the breathable sheet and the non-breathable sheet are bonded together. The method for bonding these is not particularly limited. For example, when a heat-sealable resin is used for the breathable sheet or the non-breathable sheet, the peripheral edge may be heat-sealed (heat-sealed) using the heat-fusible resin, or the peripheral edge may be bonded together using an adhesive.

[0034] The material of the non-breathable sheet is not particularly limited, but preferably, a resin sheet without pores is mentioned. The constituent resin of the resin sheet constituting the non-breathable sheet is not particularly limited. For example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polyacrylonitrile, ethylene-vinyl alcohol copolymer, polyamide, polyurethane, polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polycarbonate, etc. are mentioned. Among the resins exemplified above, polyethylene, polypropylene, ethylene vinyl acetate copolymer, and polyethylene terephthalate are preferred. The constituent resin may be used alone or in combination of two or more. Further, the non-breathable sheet may be a resin sheet vapor-deposited with a metal, preferably an aluminum vapor-deposited resin sheet, more preferably an aluminum vapor-deposited polyethylene terephthalate sheet.

[0035] Regarding the thickness of the resin sheet constituting the airtight sheet, it may be appropriately set according to the layer configuration etc. of the airtight sheet. For example, it is about 40 to 150 μm.

[0036] The airtight sheet may, if necessary, have a fiber base material laminated on the resin sheet without pores provided. Regarding the material, basis weight, etc. of the fiber base material used in the airtight sheet, they are the same as those exemplified for the breathable sheet.

[0037] [Chemical warmer] The chemical warmer of the present disclosure is packaged in a packaging material having oxygen barrier properties and provided in a state where the exothermic composition does not come into contact with air. By opening the packaging material of the present disclosure, the exothermic composition comes into contact with air and heat generation starts.

Example

[0038] Hereinafter, the present disclosure will be specifically described by giving examples etc., but the present disclosure is not limited by these in any way. 1. Metal powder The metal powder used for manufacturing the chemical warmer is as follows. · Aluminum powder A (manufactured by Toyo Aluminum Co., Ltd., product name: Aluminum powder (grade: TFH - A30P)): median diameter 30 μm · Aluminum powder B (manufactured by Toyo Aluminum Co., Ltd., product name: Aluminum powder (grade: TFH - A10P)): median diameter 10 μm · Aluminum powder C (manufactured by Toyo Aluminum Co., Ltd., product name: Aluminum powder (grade: TFH - A02P)): median diameter 2 μm · Zinc powder (manufactured by High Purity Chemical Research Institute Co., Ltd., product name: ZNE04PB): particle size 75 μm or less · Nickel powder (manufactured by Fujifilm Wako Pure Chemical Corporation, product name: Nickel powder) · Copper powder (manufactured by High Purity Chemical Research Institute Co., Ltd., product name: CUE01PB) · Magnesium powder (manufactured by FUJIFILM Wako Pure Chemical Corporation, product name: Magnesium powder (reagent special grade))

[0039] 2. Production of chemical heat packs Exothermic compositions with the compositions shown in Tables 1 and 2 were prepared. The compositions of the water retention agents in Tables 1 and 2 are as shown in Table 3. Between a breathable sheet (a laminated sheet in which a spunbond nonwoven fabric made of polyethylene terephthalate and a moisture-permeable polyethylene film are adhered by dry lamination, thickness 60 μm) and an airtight sheet (an aluminum vapor-deposited polyethylene terephthalate sheet, thickness 60 μm), 34 g of the prepared exothermic composition was held. The breathable sheet was arranged with the nonwoven fabric side on the outside. In that state, the peripheral portions of both sheets were heat-sealed to produce a rectangular chemical heat pack in which the exothermic composition was housed in a container. The width of the produced chemical heat pack is 130 mm and the length is 95 mm. Also, the width of the portion where the exothermic composition is housed is 125 mm and the length is 90 mm. Also, the area of the portion where the exothermic composition is housed is about 110 cm 2 ². Each of the produced chemical heat packs was quickly placed in and sealed in a gas-impermeable sealed bag.

[0040] 3. Evaluation of exothermic property Each of the produced chemical heat packs was taken out of the sealed bag, and the exothermic temperature of the chemical heat pack was measured using a thermo recorder (manufactured by T&D Corporation), and the exothermic property was evaluated according to the following criteria. The results are shown in Tables 1 and 2. <Evaluation criteria> A: The maximum temperature within 90 minutes from the start is 50°C or higher (exothermic) B: The maximum temperature within 90 minutes from the start is 40°C or lower (no exothermic)

[0041]

Table 1

[0042]

Table 2

[0043]

Table 3

[0044] As shown in Table 1, when using the exothermic composition containing aluminum powder and zinc powder, a chemical heat pack that sufficiently generates heat was obtained (Examples 1 to 10). On the other hand, as shown in Table 2, when using an exothermic composition containing aluminum powder, zinc powder, nickel powder, copper powder, or magnesium powder alone, or an exothermic composition containing aluminum powder and nickel powder, copper powder, or magnesium powder, a chemical heat pack that generates heat was not obtained (Comparative Examples 1 to 10).

Claims

1. A chemical heat pack in which a heat-generating composition containing an oxidizable metal is contained in a container having a breathable sheet on at least one surface, wherein the oxidizable metal contains aluminum, and the heat-generating composition further contains zinc.

2. The chemical heat pack according to claim 1, wherein the content of zinc is 1 to 30 parts by weight per 100 parts by weight of the aluminum.

3. The chemical heat pack according to claim 1 or 2, wherein the aluminum is aluminum powder, and the median diameter of the aluminum powder in the particle size distribution based on volume is 1 to 50 μm.

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