JP2853825B2 - Heating element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention generates heat by a chemical reaction that does not depend on energy such as gas or electricity, reaches a maximum temperature in a short time, and reaches a maximum temperature of 80 to 100.degree. The present invention relates to a heating element capable of heating an object to be heated.

[0002]

2. Description of the Related Art An exothermic composition comprising a mixture of iron powder and a reaction aid (eg, activated carbon, vermiculite, wood flour, etc.) mixed with a salt solution is generally used as a disposable body warmer, but is used as a human body. The maximum temperature is adjusted to around 70 ° C. to prevent low-temperature burns and the like.

[0003] For this reason, the temperature is too low for the purpose of keeping the temperature of foods and drinks, and a sufficient effect cannot be obtained.

[0004] Further, the heating element is in the form of a powder, and is used by filling in a gas permeable packing material. Therefore, when heating a vertical portion, the heating element is biased downward by gravity to cause only the lower side to be heated. There was a problem that the heating resulted in uneven heating.

To solve such a problem, Japanese Patent Application Laid-Open No. 4-130
No. 176 discloses a heat-generating packaging bag in which the heat-generating element is packed in a material having an air permeability of 0.1 to 0.5 CC / cm ² · sec and the heating temperature is raised to 90 to 100 ° C. Proposed.

However, in this packaging bag, the maximum temperature can be raised to about 90 ° C., but it takes more than 50 minutes to reach the maximum temperature. However, it cannot be applied to applications that require rapid heating to high temperatures.

Further, in order to prevent a heating element formed by accommodating a powdery heating element in a packaging material from being unevenly heated inside the packaging material during heating, Japanese Utility Model Laid-Open Publication No. 61-139219 discloses a disposable body warmer. There has been proposed a method of dividing the packaging material into small bags in order to prevent the contents from being biased.

However, in this method, even if the packaging material is divided into several parts, the heat generating material is divided so that the filling weight of the heating element into one partition is reduced. Uneven heating was not possible due to the occurrence of bias, and the manufacturing operation was only complicated, and a sufficient effect was not obtained.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a heating element composed of iron powder, a metal halide, water, and a water retaining material, reaches a high temperature of 80 ° C. or more in a short time, and uniformly heats an object to be heated. A heating element that can be heated is provided.

[0010]

Means for Solving the Problems The present invention was made as a result of the inventors' repeated studies on the composition and conditions of various exothermic agents in order to solve the above-mentioned problems. Gurley-type ventilation of a heat-generating material which contains water retention material, metal halide and water and which generates heat by contact with oxygen in the atmosphere containing iron powder of 400 cm ² / g or more in an amount of 50% by weight or more of the total amount of iron powder. The degree is 5 CC / cm ² · sec
It is stored in a packaging material made of the above materials, and filled so that the weight of the heating material with respect to the area of one side of the packaging material containing the heating material is in the range of 0.5 g / cm ² to 1.5 g / cm ^2. The size of the packaging material containing the heating material is 100 mm or less in width and 130 mm in length.
A heating element characterized in that a heating element containing a heating element and a heating material of not more than mm are formed continuously in the width direction and the longitudinal direction.

As the metal halide and water retention agent used in the present invention, materials generally used for disposable warmers can be applied. For example, the type of water retention agent is a mineral type such as activated carbon, zeolite or vermiculite, or a water absorbent resin. And the like, and NaCl, KC
1, chlorides and bromides such as CaCl ₂ can be used, and the kind and the mixing ratio are not particularly limited as long as the hydroxylation reaction of iron powder can be performed most efficiently.

In the present invention, the type of iron powder which is the main component of the reaction is any of crushed powder of cutting chips, atomized iron powder of gas and liquid, reduced iron powder of iron ore or scale, or pure iron powder produced by an electrolytic method. The iron powder is not particularly limited, but the iron powder adjusted to have a specific surface area of 400 g / cm ² or more accounts for 50% by weight or more of the mixed iron powder.

When iron powder having a small specific surface area is used, or when the mixing ratio is less than 50% by weight of the total iron powder even if the specific surface area is large, the reaction area for oxidizing reaction at the beginning of the reaction is reduced,
The heat generation rate is slow, and it takes 30 minutes or more to reach the maximum temperature, which is not preferable as the heat generation characteristic.

Therefore, in the present invention, the specific surface area of the iron powder is increased to increase the reaction rate, and the compounding ratio is increased to raise the temperature to a high temperature in a short time.

The specific surface area of the iron powder varies depending on the state of the surface irregularities and the particle size of the iron powder, and can be adjusted by appropriately selecting the surface condition and the particle size. If necessary, iron powders having different types and different particle sizes can be used in combination.

In the case of a hydroxylation reaction of iron powder used in a disposable body warmer, etc., the maximum temperature is set to 70 ° C. or less by changing the size and distribution state of the holes by concentrating holes in the central part of the packaging material. And the duration of 40 ° C. or more is adjusted.

As a result, since the supply of oxygen is a rule in the reaction of the iron powder in order to secure the duration, the iron powder is used in a state where the maximum reaction rate of the exothermic material cannot be obtained. The difference is that the heat generation characteristic does not clearly appear.

However, in the present invention, the air permeability of the packaging material is increased so that the temperature can be raised to a high temperature in a shorter time, the reactivity of the iron powder becomes a state of the exothermic reaction, and the reactivity of the exothermic material is different. The heating temperature can be controlled by adjusting the reactivity of the material by remarkably reacting with the heat generation characteristics.

The air permeability of the air hole portion of the packaging material used for general disposable warmers is 3 to 4 CC / cm ² · s.
Although this is about ec, this packaging material does not have ventilation holes on the entire surface, and only a part of the center and the like is a ventilation surface, and the packaging material as a whole drops to about 0.4 CC / cm ² · sec.

However, in the present invention, high-temperature heating can be achieved in a short time by using a material having a high air permeability over the entire surface of the packaging material.

As described above, the air permeability can be adjusted, for example, by coating a perforated polyethylene film on the surface of the nonwoven fabric and changing the shape and size of the opening. A higher air permeability can be achieved, for example, by heat sealing. It is obtained by using a nonwoven fabric made of a natural fiber material alone.

Further, the air permeability of the packaging material in the present invention has a great influence on the heat generation characteristics even if the other side of the packaging material is made of a non-permeable material as long as one side of the packaging material has a high air permeability. Even if it does not affect, it can be heated to a high temperature in a short time even if one surface is in close contact with the non-breathable material surface and the heating surface.

As such a non-breathable material, for example, an aluminum seal material, a polyvinylidene chloride coated material, or a resin-coated packaging material can be used.

However, even when the highly reactive heat-generating material is filled in the high-permeability packaging material, if the heating element is densely packed in the packaging material, the heat-generating material extends from the surface to the inside of the heat-generating material. It takes time for oxygen to permeate and react, making it impossible to raise the temperature to the maximum temperature in a short time.

When the packing density is low, oxygen easily penetrates into the heating element and rises to a high temperature in a short time. However, the temperature drops quickly, and the powder of the heating element is biased inside the packaging material and the entire surface is heated uniformly. become unable.

From the above, the present invention has a heat-generating property in which a proper amount is filled in accordance with the size of one side of the packaging material so that the material is heated to a high temperature uniformly and in a short time and kept at a high temperature for a certain time.

When the size of the packaging material to be filled with the heating element is large, the object to be heated can be easily and uniformly heated when it can be heated in a smooth and horizontal state, but has a curved surface such as a tire. When the heating surface is vertical or when the heating surface is vertical, the portion where the heating material is biased downward and the heating element is biased is heated, and the space portion is hardly heated and uneven heating is increased.

For this reason, in the present invention, the size of the packaging material to be filled with the heating element is set to be 100 mm or less in width and 130 mm or less in length. By connecting as much as necessary in the longitudinal direction, the entire surface of the object to be heated is uniformly heated to a high temperature.

The reasons for limiting the present invention will be described below. The increase in the specific surface area of iron powder increases the reaction interface, increases the reaction rate,
The maximum temperature rises.

The iron powder is not limited to a single type but may be mixed with other types of iron powder or iron powders having different particle size distributions. When the weight ratio is less than 50% by weight, the reactivity decreases.

From this fact, it is possible to heat to a high temperature in a short time by using a large amount of iron powder having a large specific surface area. Was 400 cm ² / g or more and the mixing ratio of iron powder was 50% by weight or more.

When the air permeability of the packaging material is smaller than 5 CC / cm ² · sec, the hydroxylation reaction of the iron powder becomes the supply rule of oxygen, and both the rate of temperature rise and the maximum temperature decrease, and the reaction rate of the material is suppressed. You.

As a result, the maximum reaction rate of the raw material cannot be obtained, and the material cannot be heated to a high temperature in a short time. Packaging material air permeability 5CC the packaging material the air permeability in the present invention for law law of the reaction as long 5CC / cm ² · sec or more up of the reaction conditions of the material becomes the oxidation reaction of the iron powder is obtained / cm ² · se
c or more.

In the case of the iron powder reaction rule, if a large amount of heat generating material is filled in the packaging material, the duration of the heat generating element at a high temperature is prolonged, but only the surface of the heat generating element reacts preferentially with heat, and the central part of the heat generating element reacts. Since the heat generation of the heating element slows down, the temperature of the heating element as a whole rises slowly.

From this, in the present invention, the upper limit of the packing density obtained from the ratio of the weight of the heat generating material to the area of one side of the packing material is 1.5 g / cm ² .

On the other hand, when the packing density is low, the temperature rise rate increases but the inside of the packaging material becomes unbalanced so that the portion not in contact with the heating element is not heated, and the holding time at a high temperature is short. Therefore, the lower limit of the packing density was 0.5 g / cm ² .

Further, when the size of the packaging material which is filled and sealed with the heat-generating material is increased, the bias of the material inside the packaging material is increased, and uniform heating cannot be performed.

When the object to be heated is heated in a smooth and horizontal state, the heating can be performed relatively uniformly. However, when the object to be heated has an uneven shape or a vertical portion is heated, a heating agent is stored. The larger the packaging material being used, the more unevenly the heating material becomes, resulting in uneven heating.

From this fact, the smaller the size of the packaging material to be filled with the heat generating material, the more uniform heating is possible, but if the size is too small, troubles such as clogging when filling the heat generating material into the packaging material are liable to occur. The upper limit size for filling the heating material to deteriorate the workability is set to a width of 100 mm and a length of 13.
0 mm.

When the heating surface of the object to be heated is larger than the packing size of the packaging material, a heating element having a large heating surface can be obtained by continuously using several heating elements filled in the width direction and the longitudinal direction. Production becomes possible, and stable and uniform heating can be performed.

In the case where the heating elements are made continuous in this way, if necessary, double-sided tape or the like may be provided at the sealing portion and fixed to the object to be heated to prevent the displacement.

As a result, the heating element of the present invention can be heated to a high temperature in a short period of time, and can be uniformly heated as required, having a large and complicated shape. Hereinafter, the present invention will be described based on examples.

[0043]

【Example】

[0044]

Example 1 Reduced iron powder obtained by reducing iron ore was used and the particle size was adjusted to obtain a specific surface area of 300, 400, 500,
The iron powder was 600 cm ² / g, the mixing ratio of the iron powder was changed from 30 to 100% with respect to the total iron powder used, and the remaining iron powder used was cast iron powder having a specific surface area of 300 cm ² / g.

A material consisting of diatomaceous earth, activated carbon, and vermiculite was added to the water-absorbing aid to contain 22% by weight of water, and the air permeability of the packaging material was changed to 0.2 to 8 CC / cm ² · sec to obtain a width 1.
A packing material having a packing density of 1.0 g / cm ² and having a packing density of 1.0 g / cm ^{2 on} both sides, which has a thickness of 00 mm and a length of 130 mm, is filled in an argon purged box, degassed and sealed, and stored for 24 hours. The maximum temperature of the rubber and the central part of the heating element, and the temperature rise time until the maximum temperature and 8
The high-temperature holding time of 0 ° C. or more was measured.

As a result, as shown in Table 1, when the air permeability of the packaging material is 5 CC / cm ² · sec or more, the specific surface area of the iron powder is less than 400 cm ² / g or the specific surface area is 400 c / cm ^2.
When the mixing ratio of the iron powder of m ² / g or more was less than 50% by weight, the maximum temperature was as low as 80 ° C. or less, and the heating up time to the maximum temperature was 20 minutes or more, and rapid high-temperature heating was not possible.

However, when the specific surface area is 400 cm ² / g or more and the mixing ratio is 50% by weight or more, 82
The mixture was heated to a maximum temperature of at least 100 ° C., and the heating time was shortened by the increase in the specific surface area and the mixing ratio of iron powder, and the maximum temperature reached 95 ° C.

5 CC / c whose air permeability is out of the range of the present invention
When the temperature was lower than m ² · sec, the maximum temperature was 80 ° C. or less, and the temperature raising time also took 20 minutes or more.

Even if the ventilation surface of the packaging material is one side, it is 5 CC / cm.
^At air permeability of ² sec or more, no significant difference in heat generation characteristics was observed.

The ordinary disposable body warmer of the comparative example had a maximum temperature of 61 ° C., and the time required to reach the maximum temperature was 27 minutes, which was lower than the heat generation characteristics of the present invention, and the temperature rise time was longer.

[0051]

Example 2 Reduced iron powder obtained by reducing iron ore was used, the particle size was adjusted to a specific surface area of 500 cm ² / g, and the iron powder was mixed at 70% with respect to the total iron powder used. The other iron powder used was a cast iron powder having a specific surface area of 300 cm ² / g.

A package consisting of a gas-permeable packaging material having a water-absorbing aid containing diatomaceous earth, activated carbon and vermiculite and containing 22% by weight of water and having an air permeability of 8 CC / cm ² · sec and a non-gas-permeable packaging material Was packed in a packing material of 100 mm in width and 130 mm in length at a density of 0.3 to 2.0 g / cm ^{2 in} an argon substitution box, degassed and sealed, and stored for 24 hours. It was placed horizontally and the maximum temperature around the center of the rubber and the heating element and its surroundings, and the temperature rising time until reaching the maximum temperature and the high temperature holding time of 80 ° C. or more were investigated. Table 2 shows the results.

The filling rate range of the present invention, 0.5 to 1.
In the range of 5 g / cm ² , the maximum temperature was 90 ° C. or higher, the time required to reach the maximum temperature was 12 minutes or less, which was very short, and the high temperature holding time was 40 minutes or more.

Further, the difference between the maximum temperature of the central portion of the heating element and the surrounding temperature was small and heating was uniform.

If the filling rate is less than 0.5 g / cm ^{2, the} center in contact with the exothermic agent must be at 85 ° C. within 10 minutes.
Although the temperature was raised to the above temperature, the heat generation material in the surrounding area was very low in heat capacity, and the maximum temperature reached 70 ° C., and at the same time, the temperature was lowered and the heating was not sufficient.

Conversely, when the packing density was 1.5 g / cm ² or more, the center of the heating element was in contact with the heating surface, but the periphery was separated from the heating surface, so that heating was almost impossible.

On the other hand, the maximum temperature of the contact portion in contact with the object to be heated was 85 ° C. or more, but the heating time was 25 minutes or more, the heat generation rate and the heating unevenness were large, and the material cost was increased.

[0058]

Example 3 Reduced iron powder obtained by reducing iron ore into iron powder was used, the particle size was adjusted to a specific surface area of 500 cm ² / g, and the iron powder was used in an amount of 70 wt. %
For the remaining 30%, cast iron powder having a specific surface area of 300 cm ² / g was used.

A package made of a gas-permeable packing material having a permeability of 8 CC / cm ² · sec and a non-gas-permeable packing material in which a material made of diatomaceous earth, activated carbon and vermiculite is made to contain 22% by weight of water as a water-absorbing aid. Is sealed in an argon purged box at a density of 1.0 g / cm ² at a packing rate of 1.0 g / cm ² with three rows of packaging material in a width of 100 mm and a length of 130 mm in three rows in the width direction. After degassing and sealing in a bag and storing it for 24 hours, a cylindrical resin with a diameter of 65 cm and a height of 35 cm is vertically wound around this outer surface and heated. The heating time until the temperature reached was investigated.

As a result, 10 points were measured, and the maximum temperature and the rate of temperature rise were small in each part and the maximum temperature was 87 ° C. to 92 ° C., and the temperature rise time to the maximum temperature was 10 to 1 point.
The heating time was 2 minutes, and the heating agent was continuous as a small unit, so that the cylindrical thing could be heated rapidly and uniformly to a high temperature even in a vertical state.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

[0064]

According to the present invention, rapid and high-temperature heating, which was difficult to obtain by the conventional exothermic reaction of iron powder hydroxylation, can be performed, and can be heated to a temperature of 80 ° C. or more in a short time within 15 minutes. The heater can be heated uniformly with less temperature variation on the heating surface, and by heating the heating element continuously according to the shape of the object to be heated, the heating surface having a curvature other than a flat surface can be heated uniformly. Applicable.

Claims (3)

(57) [Claims] 1. An iron powder having a specific surface area of at least 400 cm ² / g, containing at least 50% by weight of the total amount of iron powder, containing a water retention material, a metal halide and water, and generating heat upon contact with oxygen in the atmosphere. Gurley-type air permeability of 5CC / cm ²
· Stored in a packaging material made of a material longer than sec, and filled so that the weight of the heating material with respect to the area of one side of the packaging material containing the heating material is in the range of 0.5 g / cm ² to 1.5 g / cm ^2. A heating element characterized in that: 2. The packaging material containing the heat generating material has a width of 100 mm or less and a length of 130 mm or less.
Heating element as described. 3. The heating element according to claim 1, wherein the heating element containing the heating material is formed continuously in the width direction and the longitudinal direction.