JPS60219286A - Heat-generating composition - Google Patents

Abstract

PURPOSE:To keep a heat generating temp. constant over a long period of time, by using a specified polymer as a water-retaining agent in a heat-generating compsn. contg. an oxidative heat-generating agent and an oxidation accelerator. CONSTITUTION:In a heat-generating compsn. which contains an oxidative heat- generating agent such as iron powder and an oxidation accelerator such as common salt or activated carbon as the main components and generates heat in the presence of water and oxygen, a polymer having a water absorption of 0.5-5.0, such as non-rigid PVC, urea resin, phenolic resin or polyamide, is used as a water-retaining agent. The polymer is used in a quantity of 5-60wt%, pref. 10-40wt% based on that of the compsn. By blending the polymer, water required for the oxidation reaction of the metallic powder can be smoothly moved, whereby a heat-generating temp. can be kept constant over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a heat-generating composition, more specifically, a heat-generating composition as a water-retaining agent. The present invention relates to a heat generating composition characterized in that it contains a remer.

In recent years, compositions that generate heat in the presence of water and oxygen have been used as simple heat insulating materials, and most of them generate heat by oxidation of iron powder, aluminum, zinc, magnesium, copper, nickel, thorium, beryllium, etc. in the presence of water. It utilizes the heat generated when a large amount of kinko is oxidized in the air.

In addition to the oxidative heating element, this type of exothermic composition also contains a water-soluble inorganic salt (for example, chloride) as an oxidation promoter.
Jum, potassium chloride, calcium chloride, sodium sulfate, ferric chloride, copper chloride, copper sulfate, ammonium chloride)
, organic acids (e.g. citric acid, lactic acid), carbonaceous substances (e.g. activated rehydrated flour, coconut flour), or water retention agents (e.g. wood flour, vermiculite, fiber powder, super absorbent resin), etc. has been done.

The exothermic composition is convenient to carry because it can be easily generated by storing it in an airtight packaging container, opening it at the time of use, and shaking or kneading it as needed. Furthermore, it has the advantage of being chemically safe and generating relatively little excessive heat. However, conventional heat-generating compositions have had problems in that the heat-generating temperature is too high (too high) and is not always constant, and the time for maintaining a constant temperature is short. Furthermore, the heat generation temperature decreases during use, which causes the trouble of having to knead and squeeze the product many times during use.

The drawback of such conventional heat-generating compositions is thought to be due to the insufficient supply of water, which is essential for heat generation. For example, when the temperature starts to rise during heat generation, the amount of water volatilization increases, and the water is lost during the process. For a while, the temperature was seen to drop due to lack of supply of water. The above-mentioned water-retaining agent was proposed and formulated to improve this problem, but its water-retaining effect at high temperatures is still insufficient, and the rise in temperature causes gluing, which coats the surface of the gold maple powder. There were problems such as suppressing heat generation.

As a result of intensive studies to overcome such problems, the present inventor found that if a specific polymer is blended as a water retention agent in a heat-generating composition containing an oxidation exothermic agent and an oxidation promoter as main components,
They discovered a scale that can maintain a constant exothermic temperature for a long period of time, and completed the present invention.

That is, in the present invention, an exothermic composition containing an oxidation exothermic agent and an oxidation promoter as main components and which generates heat in the presence of water and oxygen contains ylE' IJ mercury having a water absorption rate of 0.5 to 5.0 as a water retention agent. It provides a heat generating composition.

The polymer used in the present invention has a water absorption rate of 0.5 to 5.0.
It is necessary to put it in between. Portrait in this invention? It is thought that the rimmer plays a role in smoothly moving the water necessary for the oxidation reaction of the gold powder into the composition.
A polymer having a water absorption rate outside the above range has an insufficient ability to move water in the composition, and therefore cannot maintain the exothermic temperature of the exothermic composition constant for a long period of time. Water absorption rate is 0.
Examples of polymers having a molecular weight of 5 to 5.0 include soft vinyl chloride, urea resins, phenol resins, and polyamide resins. It is preferable to use the polymer in the form of a powder, and those with a particle size of 100 μm or less are particularly effective. The polymer may be present in the composition in an amount of 5 to 603, preferably 10 to
40! i% is added.

As a method for incorporating water into the exothermic composition of the present invention,
Examples include a method in which water is added directly to the exothermic composition, and a method in which water is added to the exothermic composition in the form of water of crystallization, and when used, the water of crystallization is released by the heat of oxidation reaction and subjected to the reaction. It will be done. Examples of compounds that release water of crystallization include hydrous compounds such as sodium silicate, silicic acid, sodium carbonate, and sodium sulfate.

The exothermic composition of the present invention may contain various water retaining agents, bulking agents, antioxidants, gas generation inhibitors, heat storage agents, heat-sensitizing agents, exothermic inhibitors, feel improvers, to the extent that they do not impede the effects of the present invention. A reducing agent, a pigment, etc. can be added as appropriate.

In order for the heat-generating composition of the present invention to exhibit the effects of the present invention, the form of the heat-generating composition does not matter, but it is preferably formed into a molded product, for example, by compression molding.

The exothermic composition of the present invention obtained as described above is excellent in that when used, the exothermic temperature is maintained constant for a long period of time.

Next, the present invention will be explained with reference to examples. In addition, the water absorption rate in Examples was measured by the following method.

(Method for Measuring Water Absorption) Measurement was performed according to ASTM-D570iC using the following procedure. The sample used was a disk with a thickness of 1/8 inch and a diameter of 2 inches.

■ After drying the sample at 50±3℃ for 24 hours, its weight (w
ary) Th O,001t.

■ Immerse the sample in distilled water at 23±1°C for 120±4 minutes.

(2) The sample was removed from the water, the surface was wiped with dry powder, and the weight (Wwe't) was measured with an accuracy of 0.0011 as in (2).

■ Water absorption rate was calculated using the following formula.

Wary Example 1 40 parts by weight of iron powder, 20 parts by weight of salt, nylon powder
(Water absorption rate 1.5, particle size 40-100 microns) 0-40
After thoroughly mixing parts by weight and 5 parts by weight of activated carbon, a total of 15 parts by weight of water was added and mixed. Approximately 20 tf of this mixture was placed in a cylindrical mold with a diameter of 5 Q mm and heated to 100 Kl.
A molded product with a diameter of 50 mm was obtained by compression molding (using a hydraulic press) at a pressure of 1.2 cm. After storage, the molded product was taken out and the change in surface temperature of the molded product over time was measured using a surface thermometer (manufactured by Anritsu Thermo Co., Ltd.).

The room temperature at the time of measurement was approximately 10°C. The results are shown in Table 1.

The following blank rice is Toyo Rayon (made by Yusei, molding nylon rX3001)
J Spicy Shows the average temperature and maximum temperature up to 6 hours after the heating element reaches 30°C.

It shows the time required for the Spicy Spicy heating element to reach 30°C.

Example 2 The same measurements as in Example 1 were carried out using a mixture in which 20 parts by weight of polymers having various water absorption rates were added to the nylon and Q-wood of Example 1. Particle sizes of 100 microns or less were used in each case.The results are shown in Table 2.

Margin below Obi inside the front? Rimmer shows:

? Liethylene: manufactured by Mitsubishi Yuka Co., Ltd., "Yukalon" Broken ester manufactured by Nippon Uichhold Chemical Industry Co., Ltd.,
8009J Polyvinyl chloride: Zeon, manufactured by Nippon Zeon Urea resin: Fudo Light U, manufactured by Fudo Kagaku Kogyo Co., Ltd.
” ? Reacrylic acid crosslinked product: "Card 941" manufactured by B.F. Gutdrich 00. Has the same meaning as in Table 1.

After the heating element reached 30°C, the temperature decreased to below 20°C in about 1 hour.

Example 3 After thoroughly kneading 40 parts by weight of iron powder, 30 parts by weight of common salt, 5 parts by weight of activated carbon, and 15 parts by weight of vinyl chloride (water absorption rate 2.0, particle size 60-80 microns), 20 parts by weight of water was added. was added and kneaded to prepare an exothermic composition. Next, as shown in FIGS. 1 and 2, exothermic composition (1) I Ot f dF+
) The copper plate (2) was placed in a circular ethylene pig (diameter 4 Q mm), and the temperature change over time of the copper plate was measured using a surface thermometer (same as in Example 1). Same, with the above composition as a control? Similar measurements were conducted using a commercially available product that does not contain vinyl chloride. 3rd result
Shown in the table.

Table 3 Season has the same meaning as Example 1.

1 The average temperature and maximum temperature after 5 hours (in the case of the product of the present invention) or 1.5 hours (in the case of the commercially available product) after the temperature of the heating element reaches 30°C are shown.

The time period during which a heating element maintains a temperature of 30°C or higher after reaching 30°C.

[Brief explanation of drawings]

FIGS. 1 and 2 show a cross-sectional view and a plan view, respectively, of an apparatus used to measure the temperature change over time of the exothermic composition. 1-----1 Exothermic Composition 2-----1 Copper Plate Applicant: Kao Soap Co., Ltd.'-゛. Patent Attorney Toshio Takano1'-------- Patent Attorney Nobuo Ono'-1°T Co゛1-1, -j Figure 1 Figure 2 N/1

Claims (1)

[Claims] 1. An exothermic composition containing an oxidizing exothermic agent and an oxidizing promoter as main components and generating exothermic heat in the presence of water and oxygen, which is characterized in that it contains a polymer with a water absorption rate of 0.5 to 5.0 as a water retention agent. Composition.