JPH0763493B2 - Heating element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heating element, and more particularly to a heating element having a long heat generation duration and a small temperature decrease even when contacting with outside air.

[Conventional technology]

A heating composition containing iron powder, activated carbon, a water retention agent, an oxidation promoter, and water, etc., and a heating element housed in a breathable bag are widely used as chemical kairo because of cost, safety, and ease of operation. It is used. These heating elements are formed into a sheet by containing the heating composition in a thin flat bag for the purpose of improving wearability to the human body, heat transfer efficiency, and air supply to the heating composition. ing.
Usually, a desired exothermic temperature can be obtained by selecting the type of metal powder, the oxidation promoter, the water retention agent, the compounding ratio, the type of packaging material, the air permeability, and the like.

On the other hand, with the widespread use of such chemical kairo, its use is also increasing.For example, it can be attached to shoes to prevent the toes from getting cold, hold in your hands to warm your hands, and to keep the heat of hemorrhoids and other executives warm. Also, the purpose of keeping foods in containers is becoming diversified.

[Problems to be Solved by the Invention]

However, the sheet-shaped heating element is convenient to use on the flat surface of the human body from underwear or by sticking the surface with a wearing band etc., but the shape is flat and the periphery is sealed. For this reason, for example, when holding it with your hand to warm the hands, it feels uncomfortable, it does not look good, and when it is used to keep food in the container warm, the ventilation hole is blocked by closely contacting the wall of the container and the object to be kept warm. As a result, the heat generation efficiency may be reduced. Further, when it comes into contact with the outside air or a cooled floor, the internal water and heat are largely dissipated, so that not only the surface temperature is rapidly lowered but also the heat generation time is shortened.

[Means and actions for solving the problems]

The present inventors have dealt with these problems, long-lasting heat generation, less temperature drop even when exposed to cold air, as a result of continued earnest research to obtain a heating element that can be used comfortably,
It has been found that a desired heating element can be obtained by making the accommodating portion of the exothermic composition substantially spherical, and has reached the present invention.

That is, according to the present invention, in a heating element in which a heat-generating composition containing metal powder as a main component and generating heat upon contact with air is used, the heat-generating composition is packaged in a gas-permeable film and has a substantially spherical shape. It is a heating element characterized by the above.

Although the heating element of the present invention has a spherical shape, the air necessary for heating is sufficiently supplied to the inside, and exhibits excellent heating performance.

The exothermic composition used in the present invention generates heat by contacting with air, and contains, for example, metal powder such as iron and aluminum as a main component, and contains a water retention material, an oxidation accelerator and water. It is a thing.

Examples of the water-retaining material include activated carbon, wood powder, perlite, vermiculite, diatomaceous earth, various fibers and water-absorbent resin, and the oxidation promoter is usually a water-soluble inorganic salt such as NaCl, KCl. , CaCl ₂ , FeCl ₂ , FeCl ₃
And CaSO _{4 and the} like.

The breathable film used in the present invention has fine pores,
As long as it can supply the air necessary for heat generation of the heat generating composition and does not leak out the powder of the heat generating composition stored inside, and has a strength that does not damage even if a force such as rubbing with a hand is applied. The material is not particularly limited, but normally, non-woven fabric of natural fiber or synthetic fiber, woven fabric, paper, various synthetic resin films and composite films of these are used.

Examples of these materials include natural fibers such as cotton, linen silk, wool and rayon, and non-woven fabrics and woven fabrics of synthetic fibers such as nylon, polyethylene, polypropylene, polyester and polyvinyl chloride.

Further, the synthetic resin film is, for example, polyethylene, polypropylene, nylon, polyester, polyvinyl chloride, etc., and these non-breathable films are made to have breathability by making small holes with a needle, laser or electric discharge machining. Alternatively, a microporous film having a large number of micropores may be used. Among these, a composite film of a non-woven fabric and a synthetic resin film is provided with air permeability, a non-woven fabric is laminated on a microporous film, or a perforated film of synthetic resin is laminated to adjust the air permeability, or a microporous film. Partial heat fusion of the microporous part of the film itself,
Alternatively, a material whose air permeability is adjusted by applying a resin or the like is preferable. Further, these breathable films do not necessarily have to have uniform ventilation holes on the entire surface, and may have partial ventilation portions.

The air permeability of the film used in the present invention varies depending on the type and amount of the exothermic composition, the material of the film and the size of the vent and the desired exothermic temperature, and cannot be specified unconditionally, but is usually 0.5 to 30,000. Sec / 100cc (Gurley type air permeability test, according to JIS-P8117), preferably 0.5-500sec / 100cc, when the diameter of the vent hole is relatively large like 50-150μ such as needle hole. 50 to 25,0 when the pore size is relatively small, such as a microporous film with pores of 30μ or less
It is set to 00 seconds / 100cc.

In the heating element of the present invention, the exothermic composition is stored in a substantially spherical shape, but it is not necessary that the substantially spherical shape is a perfect spherical shape, and for example, an egg shape, a conical shape, or the like may be used. included. The point is that the storage portion for the heat-generating composition should be rounded as a whole, the ratio of the apparent surface area to the volume of the storage portion should be smaller than that of a flat heating element, and the shape should not have any corners. Good.

The apparent surface area does not include wrinkles or the like generated by bundling the films, and is defined as a geometric surface area when the heating element is viewed as a substantially spherical shape.

In order to obtain a heating element having such a shape, for example, the bottom portion has a hemispherical shape and the heating portion is stored in a cylindrical bag having an opening at the top, and the neck portion of the bag near the opening is tied with a string or band. A method of binding into a purse-like shape, wrapping the exothermic composition in a spherical shape with one breathable film, bundling the periphery of the film in one place, and binding this part with a string, band, etc. There is also a method of filling the exothermic composition from the mouth of a spherical bag having a mouth for filling, and then closing this mouth with another film, etc. A purse-like thing is preferable. In this case, the binding of the openings and the like may be strong enough so that the exothermic composition inside does not leak to the outside, for example, various cords and metal,
A rubber band or the like is used.

The size of the heating element varies depending on the purpose of use and is not particularly limited, but normally it is 10 to 10 in diameter when spherical.
It is set to 200 mm, preferably about 20 to 150 mm.

The heating element thus obtained is usually placed in a non-air-permeable outer bag and sealed and stored, and when taken out, heat is generated by taking it out from the outer bag, and keeps it warm in the hands and the affected area and in a container. It is used to keep foods warm.

FIG. 1 is an external view showing an example of the present invention.

In FIG. 1, a heat-generating composition 2 containing iron as a main component is wrapped in a circular and breathable film 1 in a substantially spherical shape, the periphery of the film 1 is bundled in one place, and the bundled portion is a string. 3 is bundled into a purse-like spherical heating element.

[Effects of the Invention] The heating element of the present invention is substantially spherical, and the air necessary for heat generation is efficiently supplied to the central portion, and since the evaporation of water is less than that of a conventional flat heating element, It has the characteristic that the fever duration is significantly longer. In addition, since it has a spherical structure, the vent holes are not blocked even when it comes into contact with the wall surface, etc. Moreover, the heat dissipation is small and the heat storage property is excellent, and even if it contacts cold air or the floor surface temperature Does not drop sharply. Furthermore, since it has roundness as a whole, there are no corners, and it is flexible, an excellent feel is obtained during use.

Therefore, it is possible to keep warmth for a long time even if you hold it in your hand to prevent cold hands, or if you are sitting on a cold floor etc.
A stable heat retaining effect can be obtained for a long period of time even when used for heat retaining foods.

〔Example〕

Example 1 As the exothermic composition, a mixture of 21 g of iron powder, 8.5 g of water, 1.3 g of salt, 4.5 g of activated carbon and 4.5 g of wood flour was used.

As a breathable packaging material, nylon spunbond is laminated with a microporous film, and Gurley type air permeability is 390 seconds / 100c
The packaging material of c (Brethlon manufactured by Nitto Denko Corporation) was used.

Cut the wrapping material into a circular shape with a radius of 10.3 cm including the 2 cm portion, wrap 39.8 g of the exothermic composition in a purse-like shape, and tie the neck with a string so that the end of the circular wrapping material is about 2 cm. A purse-like and spherical heating element (high temperature type) as shown in FIG. 1 was obtained.

This heating element was allowed to stand on a cushion at room temperature of 20 ° C. and relative humidity of 60% to perform a heating test. Exothermic temperature is Anritsu AM-70
It was measured with a 01-type data collector and the temperature was recorded every minute. The results are shown in FIG.

It can be seen that this heating element has approximately twice the heating duration at 40 ° C. or higher as compared with the flat heating element of Comparative Example 1 described later.

Comparative Example 1 Using the same exothermic composition and packaging material as used in Example 1, the packaging material was cut into a size of 13.5 cm in length and 10.0 cm in width, two pieces were overlapped, and three sides thereof were approximately three sides. A flat bag was made by rolling with a width of 6 mm. 39.8g of exothermic composition in this bag
After filling, the remaining one side was sealed to obtain a flat heating element. This was tested for heat generation under the same conditions as in Example 1, and the results are shown in FIG.

Example 2 The same configuration as in Example 1 but Gurley air permeability of 20,000 seconds
A spherical heating element was manufactured in the same manner as in Example 1 except that a / 100 cc packing material (Brethlon HNo4 manufactured by Nitto Denko Corporation) was used. This heating element was subjected to a heating test under the same conditions as in Example 1 and the results are shown in FIG.

Also in this case, the heat generation duration was obviously longer than that of the heating element of Comparative Example 2 described later, and the time kept at 40 ° C. or higher was about twice as long.

Comparative Example 2 The heat-generating composition and the packaging material are the same as in Example 2, but the bag has the same flat shape as in Comparative Example 1 (low temperature type).
Was manufactured and a heat generation test was performed under the same conditions as in Example 1, and the results are shown in FIG.

Example 3 A spherical heating element (medium temperature type) was manufactured in the same manner as in Example 1 except that a packaging material (Brethlon H No1 manufactured by Nitto Denko Corporation) having an air permeability of 5,330 seconds / 100 cc was used.

When this heating element was heated in the same manner as in Example 1, the heating temperature reached about 75 ° C. After 30 minutes, the heating element was moved outdoors to 5 ° C, and the surface temperature was continuously measured. As a result, a slight temperature decrease was observed, but after that, the temperature was maintained at 60 ° C or higher. Results are shown in FIG.

Comparative Example 3 Using the same packaging material as in Example 3, a flat heating element was manufactured in the same manner as in Comparative Example 1 instead of having a spherical shape. When this heating element was tested under the same conditions as in Example 3, initially,
The temperature reached 75 ℃, but when it was moved outdoors, its surface temperature dropped sharply, and after about 60 minutes, it fell below 20 ℃.

Results are shown in FIG.

Example 4 Gurley Air Permeability 1.8 seconds / 100c in which multiple holes were perforated with needles in a composite film in which polyethylene was laminated on a nonwoven fabric
A spherical drawstring-shaped heating element (high temperature type) was manufactured in the same manner as in Example 1 except that the packaging material of c was used.

This heating element was placed on the cushion and 5 in the same manner as in Example 3.
When the surface temperature was measured when it was moved outdoors at ℃, the temperature did not decrease significantly even outdoors.

Results are shown in FIG.

Comparative Example 4 Using the same packaging material as in Example 4, a flat heating element similar to Comparative Example 1 was manufactured instead of the spherical shape.

When this heat generating element was subjected to a heat generation test in the same manner as in Example 4, it showed the same heat generation as in Example 4 on the cushion.
When it is put outdoors, the temperature begins to drop in a short time, and after 40 minutes it will be 20
It fell below ℃.

Results are shown in FIG.

[Brief description of drawings]

FIG. 1 is an external view showing an example of the heating element of the present invention, and FIGS. 2 to 5 are views showing the heat generation states of the heating element of the present invention and the conventional heating element. The numbers in the drawings are as follows. 1. film, 2. exothermic composition 3. string

Claims (1)

[Claims] 1. A heating element comprising a heat-generating composition which contains metal powder as a main component and generates heat when contacted with air. The heat-generating composition is packaged in a breathable film to have a substantially spherical shape. A heating element characterized by the above.