WO2014157726A1

WO2014157726A1 - Heat generating composition, and disposable body warmer using same

Info

Publication number: WO2014157726A1
Application number: PCT/JP2014/059551
Authority: WO
Inventors: 美歌子中林
Original assignee: 興和株式会社
Priority date: 2013-03-29
Filing date: 2014-03-31
Publication date: 2014-10-02
Also published as: JPWO2014157726A1

Abstract

The present invention addresses the problem of providing: a heat generating composition that achieves an excellent heating property (heat generation increasing property) by promoting an oxidation reaction, has excellent heat generating capabilities such as long-lasting heat generation temperature sustainability (heat generation sustainability), is easily manufactured, and yet also has excellent economic efficiency; and a disposable body warmer using the same. A heat generating composition which contains an oxidisable metal powder, an inorganic electrolyte, water, a carbon component, and a water-retention agent, and generates heat in the presence of air. The carbon component uses carbon black having a DBP absorption amount of 49-150cm³/100g, and the obtained heat generating composition is housed in a bag to produce a disposable body warmer.

Description

Exothermic composition and disposable body warmer using the same

The present invention relates to a heat generating composition that generates heat in the presence of air, and a disposable body warmer using the heat generating composition.
More specifically, the present invention relates to an exothermic composition excellent in temperature characteristics such as temperature rise characteristics and exothermic sustainability and exothermic performance, and a disposable body warmer using the same.

Disposable body warmers that generate heat using the heat of metal oxidation are known.
This disposable body warmer is made of an oxidizable metal powder such as iron powder, an inorganic electrolyte as a reaction assistant, a carbon component such as water and activated carbon, and a heat-generating composition mainly composed of a water retention agent. The bag is housed in a bag, and the inner bag is hermetically packaged in an outer bag made of a non-breathable packaging material. The inner bag is taken out from the outer bag and used at the time of use.

In such disposable warmers, it is required to provide a disposable warmer that is particularly excellent in temperature rising characteristics or heat generation rising characteristics, because it is possible to raise the product value by quickly raising the temperature after taking it out from the outer bag.

Further, the temperature characteristics or heat generation performance of the disposable body warmer depends on the air permeability of the inner bag, but the reactivity with air (oxygen) also has a great influence on the temperature characteristics or heat generation performance of the disposable body warmer.
Focusing on the action of promoting the oxidation reaction of such carbon components, activated iron powder has already been proposed by forming a thin film of conductive carbon material locally on the surface of the iron powder and improving the heat generation start-up characteristics. Has been.

For example, in Japanese Patent No. 3341020 (Patent Document 1), the surface of iron powder is 0.3 to 3.0% by weight of conductive carbonaceous material selected from the group consisting of conductive graphite, carbon black, graphite and activated carbon. An active iron powder partially coated with a substance is described and disclosed to be used to construct a disposable body warmer.

The active iron powder described in Patent Document 1 is formed between the ground iron and the conductive material by locally forming a thin film of conductive carbonaceous material on the surface of the iron powder in paragraph 0015 of the document. The local battery promotes the oxidation reaction.

Japanese Patent No. 3341020

Regarding the heating element composition in a disposable body warmer or the like, it is required to have an excellent temperature rise characteristic or an exothermic rise characteristic, and it is desired that the exothermic performance such as the sustainability of the exothermic temperature is also excellent.
Furthermore, it is desired that the disposable product such as a disposable body warmer be cheaper.

However, when the active iron powder described in Patent Document 1 is used as a raw material for a disposable body warmer, although the rising characteristics of the disposable body warmer are good, in other heat generation performance such as maintaining a heat-retaining state for a long time. It is insufficient.
Therefore, in addition to the carbon component covered with the active iron powder, it is necessary to add a carbon component alone (see Example 2 of Patent Document 1).
For this reason, the amount of carbon component used increases, and the production cost may increase.

Furthermore, since the surface of the active iron powder described in Patent Document 1 is partially coated with a specific conductive carbonaceous material, a complicated manufacturing process is required. When used as, there is also a disadvantage that it is expensive.

Therefore, in order to make a disposable body warmer that is inexpensive and excellent in economic efficiency and easy to be filled at the time of manufacture while maintaining the heat generation performance, a heat generation composition that is easy to use without being bulky at the time of use is desired.

In view of such a current situation, the inventor has intensively studied a heat-generating composition that has excellent temperature characteristics such as temperature rise characteristics and heat-generation sustainability and heat generation performance, is easy to manufacture, and is excellent in economy. It was.

As a result, in the exothermic composition containing the oxidizable metal powder, the inorganic electrolyte, water, the carbon component, and the water retention agent, by selecting carbon black having a DBP absorption amount within a specific range as the carbon component, heat is generated. It has been found that the heat generation characteristics and heat generation performance such as the temperature rise characteristics of the composition and the long-term sustainability of the heat generation temperature are improved.

This invention achieves good temperature rise characteristics (heat generation rise characteristics) by promoting the oxidation reaction, and has good temperature characteristics such as long-term sustainability of heat generation (heat generation sustainability) and heat generation performance, and is manufactured. It is an object of the present invention to provide an exothermic composition that is easy to manufacture and has excellent economic efficiency, and a disposable body warmer using the same.

In order to achieve the above object, an invention according to claim 1 of the present invention is an exothermic composition containing an oxidizable metal powder, an inorganic electrolyte, water, a carbon component and a water retention agent and generating heat in the presence of air. There,
The carbon component is a heat-generating composition, wherein the DBP absorption is carbon black is 49 ^~ 150cm 3 / 100g.

The invention according to claim 2 of the present invention is an exothermic composition containing an oxidizable metal powder, an inorganic electrolyte, water, a carbon component and a water retention agent and generating heat in the presence of air, wherein the carbon component is , DBP absorption amount of the 49 ~ 150cm 3 ^/ 100g exothermic composition is carbon black which is a disposable body warmer, characterized in that housed in the bag body having an air permeability at least in part.

The exothermic composition according to the present invention contains an oxidizable metal powder, an inorganic electrolyte, water, a carbon component and a water retention agent, and uses carbon black having a specific DBP absorption amount as the carbon component. While the oxidation reaction of the oxidizable metal powder proceeds smoothly, the exothermic temperature lasts for a long time, and good exothermic performance can be obtained.

As a result, it is possible to reduce the amount of carbon components used to obtain the same heat generation performance as when using conventional activated carbon, and as a result, the amount of exothermic composition required is reduced. There are also advantages of being inexpensive and economical.

Furthermore, this exothermic composition is easy to manufacture because it does not require special processing such as coating of a conductive carbonaceous material during manufacture, and can be obtained simply by mixing the components constituting the exothermic composition. can do.

Furthermore, since the disposable body warmer of the present invention can reduce the amount of the exothermic composition required, it is easy to use without being bulky during use. In addition, there is no need for special processing such as coating processing, and it can be manufactured by an extremely easy means of mixing the carbon component with other components constituting the exothermic composition, so it is excellent in economic efficiency. Is.

It is a schematic diagram which shows the mechanism of the heat_generation | fever at the time of using iron powder as an oxidizable metal powder. It is a graph which shows the relationship between DBP absorption amount and the duration of exothermic temperature.

The exothermic composition of the present invention contains an oxidizable metal powder, an inorganic electrolyte, water, a carbon component, and a water retention agent, and is particularly preferable as a heating element for a disposable body warmer.

Before explaining the heat generating composition of the present invention, the mechanism of heat generation when iron powder is used as the oxidizable metal powder will be described with reference to FIG.

As shown in FIG. 1, electrons flow from the iron powder to the carbon component, and oxygen is reduced on the surface of the carbon component.
At that time, the reaction may proceed in the absence of a carbon component.
In this case, it is considered that oxygen reduction occurs on the surface of the iron powder. However, since the rate of this oxygen reduction reaction is slow, only slight heat generation occurs.

On the other hand, when a carbon component is present, the carbon component plays a role similar to that of a positive electrode of a battery that causes a reduction reaction of oxygen. Therefore, it is considered that the reaction is promoted catalytically.
Thus, the carbon component plays an important role in causing the reaction to proceed smoothly in the oxidation reaction of the oxidizable metal powder.

According to the mechanism of heat generation (oxidation reaction), since electrons are transferred between the oxidizable metal powder particles and the carbon component, it is desirable to select a carbon component having high conductivity.

Carbon black is an example of such a highly conductive carbon component.
This carbon black exists as an aggregated particle (called a structure) in which primary particles are linked in a chain or a tuft of grapes, and electrons flow along the continuous structure surface, so that the conductivity is very high.
Furthermore, since various functional groups such as a hydroxyl group and a carboxyl group exist on the surface of carbon black, and these functional groups make it easier for electrons to flow, in this invention, carbon is used as a carbon component. Black is adopted.

Of the other carbon components, graphite has a layered structure and is highly conductive in the direction parallel to the layer.
However, since there is almost no conductivity in the direction perpendicular to the layer and there is a direction in conductivity, when this is mixed in the exothermic composition, the reaction does not proceed uniformly.

Furthermore, although activated carbon has a large number of functional groups on its surface, it does not have a continuous structure, so that it has poor conductivity as compared with carbon black as shown in Table 1 below.

The high conductivity of the carbon black is related to the connection between the particles of the structure. The larger the structure, the higher the conductivity.
The size of this structure can be measured using the amount of dibutyl phthalate (DBP) (JISK6211) absorbed by 100 g of carbon black as an index. In general, the more the structure is developed, the larger the amount of absorption.

The exothermic compositions of the present invention, the carbon black is, DBP absorption amount of 49 ^~ 150cm 3 / 100g, preferably at a 49 ^~ 147cm 3 / 100g.

In this invention, since it uses limiting to what has the DBP absorption amount in the said specific range, oxidation of an oxidizable metal powder can be performed efficiently and smoothly.
Therefore, special processing such as coating the surface of the oxidizable metal powder with a conductive carbon material is not essential, and the specific conductive carbon material is used instead of the conventionally used carbon materials such as activated carbon and graphite. The target exothermic composition can be easily produced simply by mixing with other components.

On the other hand, according to the mechanism of the heat generation (oxidation reaction), since electrons are exchanged between the oxidizable metal powder particles and the carbon component, it is necessary that the oxidizable metal powder particles and the carbon component are sufficiently in contact with each other. I understand that there is.

Therefore, in order to form a good contact state with the oxidizable metal powder, the average particle size of the carbon component is preferably 10 to 100 nm, and more preferably 19 to 78 nm.
When the carbon component has an average particle diameter of 10 to 100 nm, that is, particles that are relatively small with respect to the oxidizable metal powder particles, almost the entire surface of the carbon component is used for energization. It is possible to obtain a heat generation effective surface.

When large particles having an average particle size of the carbon component exceeding 100 nm are used, the contact state between the oxidizable metal powder particles and the carbon component is deteriorated.
Furthermore, only a part of the surface of the carbon component in contact with the oxidizable metal powder particles can be used for energization, and not only the effective surface area for heat generation is reduced, but also more carbon components are added to facilitate the oxidation reaction. Since it becomes necessary, it tends to be unfavorable in terms of manufacturing cost and usability.

When the average particle size of the carbon component is too small, there is a concern of powder scattering during production or leakage from the air-permeable bag, and therefore, as the carbon component, using small particles with an average particle size of less than 10 nm Tend to be undesirable.
In addition, the said average particle diameter is a primary particle diameter, for example, the particle diameter of 20 particles or more is measured by electron microscope observation, and is obtained by the average.

Further, the content of the carbon component (carbon black) is preferably 0.1 to 7% by mass, more preferably 0.9 to 5% by mass, based on the entire exothermic composition.
If it is less than 0.1% by mass, there is a tendency that sufficient heat generation performance cannot be obtained as a heat generation composition.
On the other hand, even if the content exceeds 7% by mass, the oxidation reaction is not further promoted, so that it tends to be uneconomical.

Furthermore, it is preferable to select the carbon component having a purity of 90% or more.
In this case, the amount used can be reduced as compared with conventionally used activated carbon, and the amount of the exothermic composition can be reduced. Therefore, filling is easy, it is not bulky at the time of use, is easy to use, and is excellent in economy.

The oxidizable metal powder used in the present invention is not particularly limited as long as it is a metal powder that easily reacts with oxygen in the air and generates heat during the reaction.
Examples thereof include reduced iron powder, atomized iron powder, and iron iron powder.
Further, as the iron powder, a small amount of active iron powder, for example, active iron powder described in Japanese Patent No. 3341020 may be used.
The content of the oxidizable metal powder in the exothermic composition is usually 30% by mass or more, preferably 40% by mass or more, more preferably 45% by mass or more, and usually 80% by mass or less, preferably 70% by mass. Hereinafter, it is more preferably 65% by mass or less.

The inorganic electrolyte used in the present invention can be added to the exothermic composition in the form of an electrolyte solution.
Examples of such an electrolyte solution include aqueous solutions of sodium chloride, potassium chloride, calcium chloride, magnesium chloride, and the like.
The content of the inorganic electrolyte in the exothermic composition is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less, more preferably 5% by mass or less.

Examples of the water retention agent used in the present invention include silica, vermiculite, a water-absorbing polymer, and wood powder.

Examples of the water-absorbing polymer include sodium polyacrylate, crosslinked polyacrylate, polyvinyl alcohol, polyvinyl pyrrolidone, gum arabic, crosslinked polyalkylene oxide, water-soluble cellulose ether, poly-N-vinylacetamide, hydroxyethyl cellulose, methyl cellulose, Examples include sodium alginate, pectin, acrylic sulfonic acid polymer material, gelatin, polyethylene oxide, carboxymethyl cellulose and the like.
The content of the water retention agent in the exothermic composition is usually 2% by mass or more, preferably 3% by mass or more, more preferably 5% by mass or more, and usually 30% by mass or less, preferably 25% by mass or less, and more. Preferably it is 20 mass% or less.

To the exothermic composition of the present invention, other components other than the above components can be appropriately added within a range not impairing the effects of the present invention.
Examples of such components include a hydrogen generation inhibitor, a fragrance, and a deodorant.
The water contained in the exothermic composition can be used for both distilled water and tap water, and the content in the exothermic composition is usually 1% by mass or more, preferably 5% by mass or more, more preferably 10%. It is 40 mass% or less normally, Preferably it is 35 mass% or less, More preferably, it is 30 mass% or less.

A disposable body warmer can be obtained by housing the exothermic composition of the present invention in at least a part of an air-permeable inner bag.

As the inner bag, for example, a breathable bag body constituted by a breathable sheet body formed by laminating a nylon nonwoven fabric and porous polyethylene, using nylon as the outermost layer, laminating a polyethylene film on the inside, An air-permeable bag body constituted by a sheet body formed by laminating a film made of linear low density polyethylene (LLDPE) having good heat-fusibility can be used on the inside, but is not limited thereto.
For example, it can be composed of a breathable film, paper, nonwoven fabric, woven fabric or the like.

The air-permeable film can be formed into a film and is particularly limited as long as it can exhibit air-permeability by a method such as stretching and / or extraction of a soluble filler or perforation with an ultrafine needle. is not.

As such a breathable film, specifically, for example, polyethylene, polypropylene, cellophane, polyester, polyamide, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyurethane, polystyrene, ethylene vinyl acetate copolymer, polycarbonate, hydrochloric acid Rubber etc. are mentioned.
Among these, those made of polyolefin resin are preferable because a homogeneous air permeable film can be obtained by stretching or the like.

Examples of the polyolefin resin include homopolymers such as polyethylene, polypropylene, and polybutadiene, copolymers, and blend polymers thereof.
In particular, polypropylene (PP), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE) are preferable from the above viewpoint.

Furthermore, an adhesive layer may be provided on one surface of the breathable bag.
The pressure-sensitive adhesive that can be used to form such a pressure-sensitive adhesive layer is not particularly limited as long as it has good adhesion to underwear and skin.

Specifically, for example, vinyl adhesive, vinyl acetate adhesive, polyvinyl acetal adhesive, vinyl chloride adhesive, cellulose adhesive, chloroprene (neoprene) adhesive, acrylic adhesive, nitrile rubber Adhesives such as styrene-based adhesives, styrene rubber-based adhesives, silicone rubber-based adhesives, polysulfide-based adhesives, terpene resins or water-soluble rosins.
In addition, when providing an adhesion layer, in order to prevent that an adhesion layer gets dirty before use, it is preferable to coat | cover with a release paper.

As a material constituting the bag body (outer bag) made of the non-breathable packaging material, for example, a transparent vapor-deposited PET film, a biaxially oriented polypropylene plus polyethylene film laminate film, polyvinylidene chloride, polyamide, nylon, a metal vapor-deposited film , Metal oxide vapor-deposited film, metal stay laminated film, EVOH (ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer saponified product) single film, or laminated film with other film and polyethylene A composite film or a multilayer film bonded with a heat-fusible film such as polypropylene can be used.
These films are formed into a bag body, for example, by superimposing such that the surfaces of the heat-fusible film are inside each other and heat-sealing the periphery.

Hereinafter, the heat generating composition according to the present invention will be described in more detail with reference to specific examples, but the present invention is not limited to these examples.

<Examples 1 to 5 and Comparative Examples 1 to 3>
1) Manufacturing method Using the carbon components shown in Table 2 below, exothermic compositions were prepared based on the formulations shown in Tables 3 and 4 below.

<Evaluation Example 1>
With respect to the exothermic compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3, the exothermic rise time was measured by the following method.
The results are shown in Table 5.

<Measurement method>
A 93 mm × 55 mm air flow comprising the exothermic compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 formed of a breathable sheet formed by laminating a nylon nonwoven fabric and a polyethylene film and forming a needle hole, respectively. Enclosed in a sex bag.
This was further sealed in a non-breathable outer bag formed of a transparent vapor-deposited PET film to produce a disposable body warmer.
The body warmer was previously left in the measuring room (temperature 25 ° C.) and allowed to adjust to room temperature.
Thereafter, the body was opened and heat generation was started.
Cairo was wrapped with a towel (pile fabric, 100% cotton), the surface temperature of the warmer was measured, and the time until this temperature reached 40 ° C. was defined as the exothermic rise time.

<Result>
The exothermic compositions of the present invention obtained in Examples 1 to 5 all have an exothermic rise characteristic equal to or higher than that of the exothermic composition obtained in Comparative Example 2, which is an exothermic composition containing activated carbon as a carbon component. I understand that.
On the other hand, heating the composition obtained in Comparative Example 1, but is intended to include carbon black DBP absorption 180cm ^3/100 g, which is inferior in heat-generating rising characteristics than exothermic composition obtained in Comparative Example 2.
Therefore, superior heat generation rising characteristics of the invention, it is clear that is by identifying the DBP absorption amount in the range of 49 ^~ 150cm 3 / 100g.

<Evaluation Example 2>
The exothermic compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were measured for the maximum temperature from the start of exotherm to 16 hours and the average temperature during exotherm at 40 ° C. or higher. The results are shown in Table 6 and FIG.

<Result>
The exothermic compositions of the present invention obtained in Examples 1 to 5 are all exothermic compositions containing activated carbon as a carbon component, and have an exothermic performance equal to or higher than that of the exothermic composition obtained in Comparative Example 2. I understand.
Also, the exothermic compositions of the present invention obtained in Examples 1 to 5 all have a higher average temperature than the exothermic composition obtained in Comparative Example 1.
Therefore, it can be seen that the exothermic compositions of the present invention obtained in Examples 1 to 5 all have exothermic performance superior to the exothermic compositions obtained in Comparative Examples 1 to 3.
Therefore, superior heat generation performance of the invention, it is clear that is by identifying the DBP absorption amount in the range of 49 ^~ 150cm 3 / 100g.

According to the exothermic composition of the present invention, an exothermic composition having good exothermic performance, such as exothermic rise characteristics and long-term sustainability of the exothermic temperature (exothermic sustainability), easy production, and excellent economic efficiency. It is extremely useful as a heating element for disposable warmers.

Claims

An exothermic composition containing an oxidizable metal powder, an inorganic electrolyte, water, a carbon component and a water retention agent and generating heat in the presence of air,
The carbon component is exothermic composition characterized by DBP absorption is carbon black is 49 ~ 150cm 3 / 100g.
Oxidizable metal powder, an inorganic electrolyte, water, containing carbon component and water retention agent, a heat-generating composition that generates heat in the presence of air, the carbon component, DBP absorption amount by 49 ~ 150cm 3 / 100g A disposable body warmer characterized in that an exothermic composition which is a certain carbon black is housed in a bag body having air permeability at least partially.