JPS6324030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Recently, disposable type hand warmers that utilize the heat generated during the oxidation reaction of metals have become popular in the market for travel and leisure use. The heat-generating compositions used in these products are made by adding metal sulfate or chloride as a reaction aid to metal such as iron powder as the main component, and reacting with water and oxygen to generate heat. However, since these exothermic compositions use metal salts as reaction aids, they have drawbacks such as a high risk of spontaneous deterioration after use and disposal, and generally high costs. Furthermore, these exothermic compositions utilize an exchange reaction between the main component metal and the ionization tendency of the metal ion of the metal sulfate or chloride used as a reaction aid in order to obtain the temperature characteristics at the initial stage of the reaction. (For example, F _e゜ + C _u ⁺⁺ → F _e ⁺⁺ + C _u゜) The type of metal used as the main component is significantly limited by the metal ion used as a reaction aid.

The present invention was made to solve the above problems, and uses a water-soluble organic acid as a reaction aid, which is effective against all metals that have a greater tendency to ionize than hydrogen, and which has less risk of spontaneous destruction. This provides an excellent heat-generating composition that provides a suitable temperature and has a longer heat-generating time than conventional products.

The details of the present invention will be explained below. When the metal is M and C _o H _n is R, for example, when carboxylic acid is used as a reaction aid, the following reaction formula
As shown in (1), (2), and (3), the oxidation reaction progresses and generates heat of formation. This generated heat can be used as a heat source for hand warmers and the like.

M＋XRCOOH→M(RCOO) _x ＋H ₂ ...(1) M(RCOO) _x ＋XH ₂ O→M(OH) _x ＋RCOOH
...(2) M(OH) _x + YO ₂ →M _{x O y} + . These organic acids are decomposed by microorganisms in nature, so there is no need to take precautions against natural destruction, and they have excellent features such as being able to be produced at low cost.

In addition, when the above exothermic composition is used as a exothermic composition for a broken furnace, as shown in the drawing, it can be heated to an appropriate temperature (45
The exothermic time obtained (from 65°C to 65°C) is approximately 20 hours, which is an approximately 40% improvement in performance compared to the conventional exothermic composition C.

Note that effective examples of water-soluble organic acids used as reaction aids include formic acid, acetic acid, halogenated acetic acid, oxalic acid, citric acid, and tartaric acid. Among these, acetic acid and chloroacetic acid are particularly preferred.
The amount of these additives is 0.5 per 100 parts by weight of metal.
The reaction promoting effect is sufficient at parts by weight or more.

In addition, water that is commonly used may be used, and the amount added is based on 100 parts by weight of metal.
The optimal amount of addition of raw ash, carbon such as activated carbon, silica gel, wood powder, etc. as a water retaining material that can impregnate water is 10 to 100 parts by weight per 100 parts by weight of metal.

Further, although air is generally used as oxygen, oxygen gas alone or oxygen generated by a chemical reaction may also be used.

Next, an example in which the exothermic composition of the present invention is applied as a hand warmer will be described.

Thoroughly mix 30 g of iron powder as the main heating component, 10 g of raw ash as a water-retaining material, 15 cc. of water, and 1 g of acetic acid or monochloroacetic acid as a water-soluble organic acid. It was placed in a bag laminated with a sheet and having a size of 120 x 85 mm, and the opening of the bag was sealed by heat sealing, and the heat generation characteristics (temperature-heat generation time curve) as a hand warmer were measured. In this case, the heat generation temperature was measured using a copper constantan thermocouple at a temperature of 25°C and a humidity of 45°C.
It was carried out in a constant temperature and humidity room at %RH.

In addition, copper chloride is used as a reaction aid in conventional products, and the amount of addition shows the results with the best characteristics.
1.5 g was used, and the amounts of other components added were the same as in the composition ratios of the other compositions in the Examples of the present invention except for the organic acid.

The measurement results of the above conventional product and the example product of the present invention are as shown in the drawing, and as is clear from this drawing, the example products A (acetic acid) and B (chloroacetic acid) of the present invention.
Compared to conventional product C, it is possible to significantly lengthen the heat generation time at which an appropriate temperature can be obtained.

In the above examples, iron was cited as a metal with a greater ionization tendency than hydrogen, but the metal is not limited to iron, and aluminum, zinc, magnesium, etc. can also have the same effect as in the above examples. It is something that can be demonstrated.

As described above, the exothermic composition of the present invention uses as an active ingredient a metal having a greater ionization tendency than hydrogen and a water-soluble organic acid added as a reaction aid,
It generates heat when it reacts with water and oxygen, and uses a water-soluble organic acid as a reaction aid, so there is less risk of natural destruction, and the heat generation time to maintain the appropriate temperature is longer than that of conventional methods, such as when used in a pocket warmer. It has the excellent feature that it can be made significantly longer than other products.

[Brief explanation of the drawing]

The figure is a graph showing a comparison of heat generation characteristics between an example product of the present invention and a conventional product.

Claims (1)

[Claims] 1. An exothermic product characterized by the fact that the active ingredient is a metal that has a greater ionization tendency than hydrogen and a water-soluble organic acid such as acetic acid or chloroacetic acid is added as a reaction aid, and that it reacts with water and oxygen to generate heat. Composition.