JPH11318966A - Heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent exothermic composition from solidifying, even if oxidation of metallic powder such as iron powder proceeds upon use and to maintain soft touch and wearing feel, in the heating element utilizing exothermic composition made of metallic powder such as iron powder, salts and water. SOLUTION: In an inner bag 20 made of an air permeable material, heating composition 1 made by containing metallic powder, salts and water is stored and the exothermic composition 1 reacts with oxygen in air to generate heat. In the exothermic composition 1, powder of silicate consisting of crystal aggregate of 10 m<2> /g or more of specific surface preferably, powder made of spherical aggregate of acicular, planar or columnar crystal is contained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element generally called a chemical body.

[0002]

2. Description of the Related Art A heat-generating composition containing metal powder such as iron powder, salts such as salt and water, and the metal powder reacts with water and oxygen in the air by the catalytic action of the salts to be oxidized to generate heat. Heating elements utilizing an exothermic reaction are widely used, also called chemical warmers or disposable warmers.

[0003]

However, the conventional heating element using a heat-generating composition body composed of metal powder, salts and water has a problem in that the heat-generating composition of the metal powder such as iron powder progresses during use. There is a problem that the object is firmly solidified and the touch and the feeling of wearing on the body are remarkably reduced.

An object of the present invention is to solve such problems of the prior art. In a heating element using a heat-generating body composed of metal powder, salts and water, oxidation of the metal powder proceeds during use. Even so, an object of the present invention is to prevent solidification of the heat-generating composition so that a soft touch and a feeling of wearing are maintained.

[0005]

Means for Solving the Problems The present inventors have found that in a heating element using a heat generating composition containing metal powder such as iron powder, salts and water, the heat generating composition solidifies during use.
This is because the metal powder in the exothermic composition sticks with the progress of the exothermic reaction, and in order to prevent this, a powder composed of a crystalline aggregate of silicate having a large specific surface area is mixed into the exothermic composition. It was found that it was effective to complete the present invention.

That is, according to the present invention, a heat-generating composition containing metal powder, salts and water is contained in a bag made of a breathable material, and the heat-generating composition reacts with oxygen in the air to generate heat. In the body, the specific surface area is 10 m ² / g in the exothermic composition.
A heating element characterized by containing a powder composed of the above silicate crystal aggregate is provided.

In particular, in this heating element, an embodiment is provided in which each crystal constituting the crystal aggregate is formed of at least one of a needle, a plate, and a column, and the crystal aggregate is spherical.

According to the heating element of the present invention, the powder composed of the silicate crystal aggregate having a large specific surface area of 10 m ² / g or more contained in the heating composition is stable between the metal powders. Position. Therefore, the metal powders are prevented from sticking to each other during the progress of the exothermic reaction, whereby
Consolidation of the exothermic composition with the progress of the exothermic reaction is prevented.
Therefore, this heating element always exhibits a soft touch and a feeling of wearing when used.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the heating element of the present invention will be described below in detail with reference to the drawings. In each of the drawings, the same reference numerals represent the same or equivalent components.

FIG. 1 is a configuration diagram of one embodiment of a heating element 10 according to the present invention. The heat generating element 10 has a structure in which the heat generating composition 1 is housed in an inner bag 20 made of a gas permeable material and sealed with an outer bag 30 made of a non-air permeable material, similarly to a conventional heat generating element. ing.

The heating element 10 has a specific surface area of 10 m ² / g or more, preferably 25 m ² / g or more in the heating composition 1.
More preferably, a powder comprising a silicate crystal aggregate of 40 m ² / g or more is contained. Here, the specific surface area refers to a value obtained by a BET method.

The form of each crystal constituting the crystal aggregate is preferably acicular, plate-like, or column-like in view of the effect of preventing caking and the mixing or dispersibility with other powders.
The overall shape of the crystal aggregate is preferably spherical.

As a typical example of such a crystal aggregate,
The following general formula (1)

[0014]

## STR2 ## _{aM 2 O · bAl 2 O 3} · cSiO 2 · dR m A n · yH 2 O (1) ( wherein, M = Na or K, R = Na, K, Ca or M
g, A = CO ₃ , SO ₄ , NO ₃ , OH or Cl, a
= 1-6, b = 2-8, c = 2-12, d = 0
4, m = 1 to 2, n = 1 to 3, y = 0 to 32).

In particular, spherical aluminosilicate having a main diffraction peak at d = 3.65 ± 0.15, or J
CPDS No. 20-379, 20-743, 25-7
76, 25-1499, 25-1500, 30-117
0, 31-1272, 34-176, 35-479, 3
5-653, 38-513, 38-514, 38-51
A canclinite-like aluminosilicate exhibiting an X-ray diffraction pattern of 5, 45-1373 is preferable. In particular, in the composition formula (1), a = 3, b = 3, c = 6, d = 2,
Cancrinite-like aluminosilicates in which R = Na, m = 1 and n = 0 to 6 are preferred.

Regarding the size of the crystal aggregate, if the particle size is too small, a sufficient anti-caking effect cannot be obtained, and if it is too large, the miscibility with other powders is reduced. 1 to 500 μm is preferable, and 1 to 100 μm is more preferable.
m is preferred.

As a method of synthesizing such a crystal aggregate, for example, in the case of spherical aluminosilicate, alumina raw material and silica raw material are mixed with CO ₃ , SO ₄ , NO ₃ , Cl
It can be obtained by reacting in an alkaline solution in the presence of ions.

In this case, aluminum oxide, aluminum hydroxide, sodium aluminate and the like can be used as the alumina raw material, and silica sand, silica sand,
Silica stone, water glass and the like can be used, and kaolin, mica, talc and the like can be used as raw materials of alumina and silica. Further, as the alkaline raw material, N
a, Ka oxides, hydroxides, carbonates and the like can be used, and if necessary, Ca, Mg oxides, hydroxides, carbonates and the like can be used.

Typical production examples of the crystal aggregate include, for example, 30% of water glass, 27% of sodium aluminate,
28% of sodium nitrate and 15% of sodium hydroxide (above, in terms of anhydrous weight) are mixed so as to have a slurry concentration of about 5%, and reacted at 80 to 100 ° C. for 18 to 24 hours to grow needle crystals. The obtained crystal is
By filtering, washing with water, drying at about 105 ° C., and crushing, a silicate powder having a desired shape can be obtained.

The exothermic composition 1 used in the exothermic body 10 of the present invention is not particularly limited with respect to other components except that it contains a powder composed of a silicate crystal aggregate having a specific property as described above. And a heat-generating composition used for a known heat-generating element.

For example, iron, zinc, aluminum, copper and the like can be used as the constituent metal of the metal powder contained in the exothermic composition.

Examples of the salts include chlorides of alkali metals such as sodium chloride and potassium chloride and chlorides of alkaline earth metals such as calcium chloride and magnesium chloride.

As the water-retaining agent, it is preferable to use a water-retaining agent having a high water-retaining ability and capable of eliminating free water in the step of preparing the exothermic composition. For example, vermulite, calcium silicate, silica gel, silica-based porous Substances, alumina, pulp, wood flour, water-absorbing polymers and the like. These can be used alone or in combination of two or more. Among them, sodium polyacrylate, water-soluble cellulose ether, poly-N-vinylacetamide, carboxymethylcellulose, and the like are used as the water-absorbing polymer, and the combination of the water-absorbing polymer and silica gel relatively increases the mixing ratio of the water retention agent. This is preferable because it can be made smaller.

Examples of the reaction accelerator include activated carbon, carbon black, graphite and the like.

In addition, the exothermic composition may contain various additives such as an exothermic accelerator, an odor absorbing agent, other various fragrances, and a hydrogen generation inhibitor, if necessary.

Regarding the mixing ratio of each component of the heat-generating composition, the powder of the crystal aggregate having the above-mentioned specific shape is usually used in an amount of 0.
5 to 25% by weight, and other main components are 40 to 60% by weight of metal powder such as iron powder and water 1 as in the conventional example.
It may be 0 to 30% by weight, 1 to 5% by weight of a salt such as salt serving as a catalyst, and 1 to 10% by weight of a water retention agent for preventing evaporation of water.

The exothermic composition is prepared, for example, as follows.

First, 1 to 20% by weight, preferably 5 to 1%
A 5% by weight aqueous solution of a salt such as a 5% by weight saline solution is added to a water-retaining agent such as a water-absorbing polymer in a weight ratio of 5 to 20 times, preferably 10 to 20 times.
After adding about twice the salt aqueous solution to absorb the water retention agent sufficiently,
Stir well to obtain a water-retaining agent in which salts are dispersed. On the other hand, if necessary, a reaction accelerator is added in an amount of 0.5 to 10% by weight, more preferably 4 to 5% by weight, based on metal powder such as iron powder. Then, to the metal powder, a water-retaining agent in which the above-mentioned salts are dispersed is added in a weight ratio of 0.1 to 4 times, preferably 0.5 to 2 times, to obtain an exothermic composition.

In the present invention, as shown in FIG.
Inner bag 2 in which exothermic composition 1 as described above is made of a breathable material
However, the structure of the inner bag 20 is not particularly limited as long as air permeability that can maintain a predetermined exothermic reaction is secured. For example, as a constituent material having air permeability, synthetic resin films and rubbers (for example, polyethylene, polypropylene, polyamide, polyester, polyvinylidene chloride, polyurethane, polystyrene, ethylene- Saponified vinyl acetate copolymer, ethylene-vinyl acetate copolymer, natural rubber, recycled rubber, synthetic rubber, etc.), woven fabric, nonwoven fabric, and a film obtained by laminating two or more of these can be used. As a constituent material of such an inner bag 20, a commercially available product can be used.

The entire surface of the inner bag 20 may be made of the above-described air-permeable material. However, as shown in FIG. A non-breathable material, such as a laminated sheet of an ethylene-vinyl acetate copolymer sheet and a polyethylene sheet, may be provided with an adhesive surface thereon so that it can be easily attached directly to the skin or through clothing.

On the other hand, in the heating element 10 of the present invention shown in FIG. 1, the outer bag 30 made of a non-breathable material seals the inner bag 20 directly containing the above-mentioned exothermic composition 1 to cause an exothermic reaction. Can be removed.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Reference Example 1: Synthesis of silicate crystal aggregate powder used in Examples 1 and 2 860 g of sodium aluminate, 14 sodium hydroxide
50 g of sodium nitrate and 1530 g of sodium nitrate in deionized water 27
No. 3 sodium silicate (Na)
₂ O = 9.7%, SiO ₂ = 29.7%, H ₂ O = 60.
6%) to obtain a powder. The obtained powder had a porous spherical shape in which needle-like crystals were aggregated as shown in FIG. The specific surface area of this powder by the BET method is 5
It was 8 m ² / g. As a result of X-ray diffraction, d = 0.
A strong diffraction peak was observed at 366 nm, and JCPDS N
o. 38-513. The composition is approximately 3N
a ₂ O.3Al ₂ O ₃ .6SiO ₂ .Na (NO ₃ ) .4H ₂
O.

Reference Example 2: Synthesis of silicate crystal aggregate powder used in Example 3 Kaolin 5 was added to a solution in which 1120 g of potassium hydroxide and 850 g of sodium nitrate were dissolved in 5000 mL of ion-exchanged water.
0 g was mixed and dispersed, and reacted at 80 ° C. for 24 hours with stirring. After the reaction, the mixture was washed, filtered, and dried. The resulting powder is
As shown in FIG. 3, a plate-like crystal was in a porous spherical shape. The specific surface area of this powder was 76 m ² / g. As a result of powder X-ray diffraction, d = 0.368 n
m has a strong diffraction peak, and the composition is roughly 2Na ₂ O ·
3Al ₂ O ₃ .6SiO ₂ .2Na (NO ₃ ) .6H ₂ O.

Reference Example 3: Synthesis of silicate crystal aggregate powder used in Example 4 Kaolin 5 was added to a solution of 800 g of sodium hydroxide and 850 g of sodium carbonate dissolved in 5000 mL of ion-exchanged water.
0 g was mixed and dispersed to obtain a powder. As shown in FIG. 4, the obtained powder had a porous spherical shape in which columnar crystals were aggregated. The specific surface area of this powder was 30 m ² / g. As a result of powder X-ray diffraction, it had a strong diffraction peak at d = 0.368 nm, and the composition was roughly 3Na ₂ O · 3A.
l ₂ O ₃ · 6SiO was _{2 · Na 2 CO 3 · 2H} 2 O.

Example 1 and Comparative Examples 1 to 4 As shown in FIG. 1, a heating element 10 having a structure in which the exothermic composition 1 is housed in an inner bag 20 and further housed in an outer bag 30.
It was created.

In this case, the inner bag 20 is 11 × 7.5 cm.
² Size Satoshi to form the surface member 21 breathable laminate (manufactured by Nitto Denko Corporation, BRN-26) from. Further, a laminated material in which the back material 22 of the inner bag 20 is laminated with a non-breathable backing sheet with an adhesive (Nittack, manufactured by Nitto Denko Corporation)
Formed from

As the exothermic composition 1, the components shown in the following Table 1 were blended, and 30 g of this was filled in the inner bag 20.

[0039]

[Table 1] Exothermic composition components (product name, manufacturer name) Compounding amount (g) Iron powder (RKH, Dowa Kogyo) 30 Purified water 14.25 Salt (manufactured by Japanese salt) 0.75 Water retention agent (Iaric CAw4s, Nippon Shokubai) 5 Powder in Table 2 12.5

[0040]

[Table 2] Powder (product name, manufacturer name) Powder shape After heat generation Collapse strength of powder Specific surface area Example 1 Aluminosilicate (Kao) Needle-shaped crystal spherical aggregate 850 (gf) 58 (m ² / g) Comparative example 1 None -1260-Comparative Example 2 Alumina (Kao) amorphous * 1058 3.8 Comparative Example 3 Aluminosilicate (Toyofilter, Tosoh) Tetrahedron * 1308 32 Comparative Example 4 Activated carbon (carborafine, Takeda Pharmaceutical) Irregular * 1100 1430 (Note) *: Powder is not a crystal aggregate

The heating elements of Examples and Comparative Examples were left in the air at 25 ° C. to generate heat. After 12 hours had passed, the collapse strength of the heat-generating composition was measured using Tensilon RTC-1150A (Orientec, test speed 300 mm / min, load range 10 kgf). In addition, the larger the numerical value of the disintegration strength due to Tensilon, the more the solidification is progressing. The specific surface area of the powder used in each of the examples and comparative examples was determined by the BET method. Table 2 shows the results.

The micrograph of the powder used in Example 1 is an aggregate of needle crystals as shown in FIG. As a control, a micrograph of the powder used in Comparative Example 3 is shown in FIG.

Examples 2 to 4 and Comparative Examples 5 to 11 In place of the exothermic composition of Table 1, the exothermic composition of Table 3 was used.
A heating element was prepared in the same manner as in Example 1, except that 20 g of the heat-generating composition was filled in an inner bag (13 × 9.5 m ² ).

[0044]

[Table 3] Exothermic composition components (product name, manufacturer name) Compounding amount (g) Iron powder (Wako Pure Chemicals) 20 Purified water 9 Salt (Wako Pure Chemicals) 1 Water retention agent (IARIC CAw4s, Nippon Shokubai) 1 Water retention Agents (Niffel Seal VN-3, Nippon Silica) 3 Powders in Table 4 5

[0045]

[Table 4] Powder (trade name, manufacturer name) Powder shape After heat generation Collapse strength of powder Specific surface area Example 2 Aluminosilicate (Kao) Spherical aggregate of needle-shaped crystals 4 (kg) 58 (m ² / g) Example 3 Alumino Silicate (Kao) Plate-shaped crystal spherical aggregate 5.1 76 Example 4 Aluminosilicate (Kao) Columnar crystal spherical aggregate 4.2 30 Comparative Example 5 None-6.4-Comparative Example 6 Aluminosilicate (Toyofilter, Tosoh) Tetrahedron 10 32 Comparison Example 7 Silicon Carbide (Kao) Amorphous 9.1 3 Comparative Example 8 Aluminosilicate (Mullite, Kao) Plate Crystal 6.4 3.5 Comparative Example 9 Hamiculite (Toyo Permiculite) Irregular 13.2 6.8 Comparative Example 10 Magnesium Oxide (Akohosei) Irregular 12.1 0.1 Comparative Example 11 Salt (Ako Kasei) Tetrahedron 15 0.1

The obtained heating element was heated under the same conditions as in Example 1. After 12 hours, the collapse strength of the heat-generating composition was tested with a KM hardness tester (KIYA). In addition, the disintegration strength by a KM hardness tester, like Tensilon, indicates that the larger the numerical value, the harder the consolidation is progressing. The specific surface area of the powder used in each of the examples and comparative examples was determined by the BET method. Table 4 shows the results.

The micrograph of the powder used in Example 2 is
As shown in FIG. 2 described above, it is an aggregate of needle-like crystals, and the micrographs of the powders used in Examples 3 and 4 are plate-like crystals and columnar crystals as shown in FIGS. 3 and 4, respectively. Is an aggregate of

[0048]

According to the present invention, in a heating element utilizing an exothermic reaction of a heat-generating composition comprising metal powder such as iron powder, salts and water, oxidation of metal powder such as iron powder proceeds during use. Even so, caking of the exothermic composition is prevented. Therefore, the heating element of the present invention maintains a soft touch and a feeling of wearing, and is particularly suitable for applications in which the body is worn on the body and locally warms the body, and is used to alleviate back pain, stiff shoulders, menstrual pain and the like. It will be useful.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a general heating element.

FIG. 2 is an electron micrograph of a spherical aggregate of needle-like crystals of aluminosilicate used in Examples 1 and 2.

FIG. 3 is an electron micrograph of a spherical aggregate of plate-like crystals of aluminosilicate used in Example 3.

4 is an electron micrograph of a spherical aggregate of columnar crystals of aluminosilicate used in Example 4. FIG.

FIG. 5 is an electron micrograph of an aluminosilicate crystal used in Comparative Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exothermic composition 10 Heating element 20 Inner bag 21 Surface material 22 Back material

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takanori Kodera 1334 Minato 1334 Minato, Wakayama City, Wakayama Prefecture, Japan Inventor Mikio Sakaguchi 1334 Minato, Wakayama City, Wakayama Prefecture, Kao Corporation (72) Invention Person Yasuki Eguchi 2-1-3 Bunka, Sumida-ku, Tokyo Inside Kao Corporation Research Laboratory

Claims (5)

[Claims] 1. A heating element which contains a heat-generating composition containing metal powder, salts and water in a bag made of a gas-permeable material, wherein the heat-generating composition reacts with oxygen in air to generate heat.
A heating element, characterized in that the heating composition contains a powder comprising a silicate crystal aggregate having a specific surface area of 10 m ² / g or more. 2. The heating element according to claim 1, wherein each of the crystals constituting the crystal aggregate is at least one of a needle, a plate, and a column. 3. The crystal aggregate according to claim 1, wherein the crystal aggregate is spherical.
Heating element as described. 4. The heating element according to claim 3, wherein the crystal aggregate is made of aluminosilicate. 5. A crystalline aggregate, the following equation (1) ## STR1 ## _{aM 2 O · bAl 2 O 3} · cSiO 2 · dR m A n · yH 2 O (1) ( wherein, M = Na or K, R = Na, K, Ca or M
g, A = CO ₃ , SO ₄ , NO ₃ , OH or Cl, a
= 1-6, b = 2-8, c = 2-12, d = 0
4. The heating element according to claim 1, comprising a spherical aluminosilicate represented by the following formula: 4, m = 1 to 2, n = 1 to 3, y = 0 to 32).