JPS6249317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Recently, disposable type hand warmers that utilize the heat generated during the oxidation reaction of iron have become popular in the market for travel and leisure use. The exothermic compositions used in these applications are those in which a metal chloride or sulfate is added as a reaction aid to iron powder, which is the main component, and the mixture reacts with water and oxygen to generate heat. However, in order to obtain the temperature characteristics at the initial stage of the reaction, these exothermic compositions utilize an exchange reaction between the main component iron and the ionization tendency of the metal ion of the metal chloride or sulfate used as a reaction aid. Therefore, the metal salts that can be used as reaction aids (for example, Fe゜＋Cu ⁺⁺ →Fe ⁺⁺⁺ Cu゜) are severely limited.
Moreover, since these metal salts are generally noble metals, they have the problem of high cost. Furthermore, among the metals constituting the chloride or sulfate, if the metal has a greater ionization tendency than iron, the initial exchange reaction will not take place, the temperature characteristics will be extremely poor, and the metal will not be effective as a heat generating agent.

In view of the above points, the present invention provides a high exothermic temperature and a long exothermic time by adding a water-soluble hydrazine inorganic acid salt as a reaction initiator and adding a metal oxide as an auxiliary reaction composition. The present invention provides an instant composition.

The details of the present invention will be explained below. Iron, which is the main component of the heat generating composition of the present invention, may be any iron material that can generate heat, and may be in the form of powder, granules, etc. Furthermore, it is not necessary to use a highly pure metal chloride or sulfate as a reaction aid, and the amount added is approximately 0.5 to 20 parts by weight per 100 parts by weight of iron. In this case, inexpensive alkali metal or alkaline earth metal salts may be used, and seawater or the like may also be added.

Furthermore, the water-soluble hydrazine inorganic acid salt as a reaction initiator and the metal oxide as an auxiliary reaction aid do not need to be of particularly high purity.
It is sufficient to add 0.5 parts by weight or more of the water-soluble hydrazine inorganic acid salt and 1 to 20 parts by weight of the metal oxide per 100 parts by weight of iron.

In addition, any commonly used water may be used, and the amount added is 10 parts by weight per 100 parts by weight of iron.
~100 parts by weight, in which case seawater is also possible. The optimal amount of water-retaining materials that can be impregnated with water, such as raw ash, carbon such as activated carbon, silica gel, and wood powder, is 10 to 100 parts by weight per 100 parts by weight of iron.

Furthermore, air is generally used as oxygen.

Next, an example in which the exothermic composition of the present invention is applied as a hand warmer will be described. First, the bag to contain the exothermic composition is made of a non-woven fabric laminated with a 30μ thick polyethylene sheet and has a size of 120 x 85 mm.
mm was used. The mixing ratio of the exothermic composition is 30 g of iron powder, 10 g of raw ash as a water retaining material, 0.5 g of hydrazine hydrochloride as a water-soluble hydrazine inorganic acid salt serving as a reaction initiator, 15 c.c. of water, and 1.5 g of copper oxide as a metal oxide.
g, Nacl2g is a metal chloride that has a greater ionization tendency than iron. These mixtures were placed in the bag, and the opening of the bag was sealed by heat sealing, and the heat generation characteristics (heat generation temperature - heat generation time characteristics) as a hand warmer were measured. In this case, the heat generation temperature was measured using a copper constantan thermocouple at an air temperature of 25°C.
The experiments were conducted in a constant temperature and humidity room with a humidity of 45% RH.

In addition, Figure 1 shows A when no reaction initiator is added.
This shows a comparison of the exothermic properties of B, where a reaction initiator is added but no copper oxide, and C, where both a reaction initiator and copper oxide are added.
As is clear from FIG. 1, in the case where no reaction initiator is added, the heat generation starts slowly and the heat generation temperature is low, so that it has almost no effect as an exothermic agent. In addition, in case B does not contain copper oxide,
When copper oxide is added, the exothermic temperature is slightly lower than that of C, and the initial temperature characteristics are also poor.

Figure 2 shows a comparison of the exothermic properties at low temperatures between conventional product D, which uses conventionally used copper chloride as a reaction aid, and the above-mentioned example product E of the present invention. As is clear from the figure,
Conventional product D has an appropriate temperature range X when used as a pocket warmer.
(45°C to 65°C) is about 5 hours, whereas Example Product E of the present invention takes about 10 hours or more. From this, it can be seen that Example product E of the present invention
It has excellent performance even at low temperatures, and is particularly effective for use in cold regions and outdoors during the winter. The low-temperature heat generation temperature was measured using a copper constantan thermocouple in a constant temperature and humidity room with an air temperature of 5°C and a humidity of 60% RH.

In the above example, copper oxide was used as a metal oxide, but other examples include manganese, chromium, calcium,
Oxides of cobalt, nickel, and magnesium are effective, and even if they are added alone or as a mixture of a plurality of them, the same effects as in the above embodiments can be obtained.

As described above, in the exothermic composition of the present invention, the water-soluble hydrazine inorganic acid salt is added as a reaction initiator, and the metal oxide is added as an auxiliary reaction aid, so that the exothermic composition quickly generates heat. It also has various excellent features, such as a high heat generation temperature and a long heat generation time that provides an appropriate temperature range when used as a hand warmer.

[Brief explanation of the drawing]

Figure 1 is a graph showing a comparison of exothermic characteristics between the example product of the present invention and the product without copper oxide or reaction initiator added, and Figure 2 is a graph showing the comparison between the conventional product and the product of the present invention. It is a graph showing a comparison of heat generation characteristics at low temperatures with Example products.

Claims (1)

[Scope of Claims] 1 Iron and a chloride or sulfate of a metal with a greater ionization tendency than iron are used as active ingredients, and a metal oxide is added to this active ingredient as an auxiliary reaction aid, and a water-soluble 1. A heat-generating composition containing a hydrazine inorganic acid salt as a reaction initiator, which reacts with water and oxygen to generate heat. 2 The oxides of the metals include copper, manganese, chromium,
2. The exothermic composition according to claim 1, which is an oxide of the group consisting of calcium, cobalt, nickel, and magnesium, and is added singly or as a mixture of a plurality of these.