JPH10108876A - Sheet heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sense of incompatibility at the time of fitting and keep the comfortable temperature for a long period. SOLUTION: A nonwoven fabric A and a nonwoven fabric B are entangled by the water jet method, a heating powder composition is scattered and held on it, a nonwoven fabric C is superposed on it, and they are compressed or heat-compressed to form this sheet-like heating element. A dry nonwoven fabric having the apparent specific gravity of 0.15 or below is preferably used for the nonwoven fabric A, an wet nonwoven fabric having the apparent specific gravity of 0.15 or above is used for the nonwoven fabric B, and the thickness of the sheet-like heating element is set to 5mm or below. This sheet-like heating element is heated and compressed by a heat embossing roll.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-shaped heating element, and more particularly to a thin and easy-to-use sheet-shaped heating element which does not move or shift a heat-generating powder composition.

[0002]

2. Description of the Related Art Conventionally, a heating element which contains a powder composition mainly composed of an oxidizable metal and which generates heat upon contact with oxygen in the air in a bag having air permeability is widely used for warming. Have been. However, when the powder composition is worn on a human body, the powder composition is deviated due to gravity or the like, causing a sense of incongruity and also generating heat. As a method of solving this drawback, various proposals have been made in which the support is held on a support or the like to form a sheet.

For example, a method of retaining a heat-generating composition in a mesh (JP-A-53-84246) and a method of impregnating an activated carbon fiber non-woven fabric with an oxidizing aid and laminating a metal foil (JP-A-63-37181) Gazette), a method of impregnating Japanese paper with an oxidation aid, spraying a heating agent, and then press-forming (Japanese Utility Model Application Laid-Open No.
No. 4,018,018), a method of laminating a nonwoven fabric of vegetable fibers and heat-fusible fibers, and dispersing a chemical exothermic agent therein (Japanese Patent Application Laid-Open No. 2-142561). A method in which a heating agent is dispersed and held on a gap sheet-like support (Japanese Patent Laid-Open No. 3-152894), a high-voided nonwoven fabric and a nonwoven fabric are overlapped with an adhesive, a heat generating composition powder is sprayed on the upper surface, and the nonwoven fabric is further stacked. There is a method of thermocompression bonding (JP-A-8-112303) and the like.

[0004]

However, the sheet heating element obtained by these methods has the following problems. The rigidity of the sheet heating element is large, and the powder of the heating composition is easily released. The surface area of the metal foil is so small that sufficient heat generation characteristics cannot be obtained. The exothermic agent easily peels off due to bending of the sheet-like heating element. Nonwoven fabrics are easily separated from each other by vegetable fibers for providing water retention. Since the suspension is sprayed after the exothermic composition is maintained in a dispersed state, it is difficult to maintain the uniformity. Since the high void non-woven fabric and the non-woven fabric are overlapped with an adhesive, when worn on the human body, there is still a sense of incongruity when bending,
In order to adhere sufficiently, the voids of the nonwoven fabric are filled with the adhesive, so that oxygen is mainly supplied from only one side, and when a sufficient amount of heat-generating composition is sprayed, the heat retention is inferior and uniform heat is generated. It is difficult to obtain the property.

As described above, there has been a demand for the development of a sheet-like heating element that maintains a heat-generating powder composition uniformly, is stable against bending and vibration without powder leakage, and has little discomfort during use. .

[0006]

According to the sheet heating element of the present invention which achieves the above object, at least a non-woven fabric A and a non-woven fabric B are entangled by a water jet, and the exothermic powder composition is held on the non-woven fabric A. Further, it is obtained by superimposing the nonwoven fabric C on the upper surface of the exothermic powder composition, compressing or heating and compressing, and then impregnating with water or an aqueous liquid.

[0007]

Embodiments of the present invention will be described below in detail. In the first invention, at least the nonwoven fabric A is superimposed on the upper side and the nonwoven fabric B is laminated on the lower side and entangled by the water jet method, and then the exothermic powder composition is held on the upper surface of the nonwoven fabric A side. A sheet-shaped heating element obtained by superimposing the nonwoven fabric C on the upper surface of the body composition, compressing or heating and compressing, and then impregnating with water or an aqueous liquid.

In the present invention, the exothermic powder composition includes:
Mainly composed of oxidizable metal powder such as pure iron, reduced iron, nickel, etc., activated carbon as an oxidation promoter, inorganic electrolytes such as sodium chloride, calcium chloride, perlite, sebiolite, vermiculite, diatomaceous earth, activated clay, zeolite, water absorption A water retention agent such as a resin, water and the like are mixed.

The water jet method of the present invention is a method in which a high-pressure water jet is applied to a fiber web on a woven belt on a perforated drum or a roller without holes to entangle the fibers. Method, jet punch method, etc.

[0010] By entanglement of the nonwoven fabrics by the water jet method, the resulting nonwoven fabrics can be integrated without lowering the air permeability. When the exothermic powder composition is held on the integrated nonwoven fabric, the method of sucking from the surface opposite to the surface to be held is performed while the exothermic powder composition is strongly held by the nonwoven fabric. It is preferable that the nonwoven fabric is entangled by the water jet method because the nonwoven fabric has good air permeability and is effectively sucked. Furthermore,
Since the nonwoven fabric has good air permeability, oxygen necessary for the exothermic reaction can be supplied from both sides, and uniform heat generation can be obtained.

Further, the treatment by the water jet method has an advantage that the hardness of the nonwoven fabric is reduced and the nonwoven fabric has a soft touch, thereby reducing the sense of discomfort during use.

The present invention particularly holds the exothermic powder composition when the exothermic powder composition is sprayed on the upper surface of the nonwoven fabric A side of the nonwoven fabric composite in which the nonwoven fabric A and the nonwoven fabric B are entangled by the water jet method. A sheet-like heating element obtained by suction from the surface on the nonwoven fabric B side opposite to the surface to be formed is preferable.

[0013] By suction, the heat-generating powder composition holding property to the non-woven fabric A is strengthened and reaches deep holes, so that when the sheet-like heating element is moved or used, the number of pieces becomes smaller than that of a piece. Further, since the amount of the exothermic powder composition held firmly per unit area can be increased, uniform exothermic properties can be obtained for a long time.

[0014] The degree of suction is not particularly limited, but generally the pressure difference is 5mmH ₂ O~200mmH ₂ O about. If the temperature is too low, the retention of the exothermic powder composition on the nonwoven fabric is poor. If the temperature is too high, the activated carbon passes through the nonwoven fabrics A and B, which is not preferable.

In the present invention, the nonwoven fabric A having an apparent specific gravity (hereinafter, simply referred to as an apparent specific gravity) of 0.15 or less calculated from the basis weight according to JIS-L1096 and the thickness at a load of 50 gf / cm ² is referred to as an upper side and a lower side. The nonwoven fabric B having an apparent specific gravity of 0.15 or more is overlapped on the nonwoven fabric A side, and the two layers are entangled by the water jet method. Then, the exothermic powder composition is held on the surface of the nonwoven fabric A side. A sheet-like heating element obtained by superimposing the nonwoven fabric C on the upper surface of the sheet, compressing or heating and compressing, and then impregnating with water or an aqueous liquid is preferable.

The reason why the apparent specific gravity of the nonwoven fabric A is preferably 0.15 or less is because the exothermic powder composition is easily held in a state where the void portion is clogged. Preferably, the average void diameter on the surface of the nonwoven fabric A measured by an electron microscope or an optical microscope is 50 μm to 500 μm.

The reason why the apparent specific gravity of the nonwoven fabric B is preferably 0.15 or more is to hold the exothermic powder composition leaking through the nonwoven fabric A. Preferably, the average void diameter on the surface of the nonwoven fabric B measured by an electron microscope is 30 μm or less.

In the present invention, the apparent specific gravity of the nonwoven fabric A is particularly preferably 0.10 or less. This is because the exothermic resin composition is more likely to be clogged in the voids and is more easily held. Preferably, the average void diameter under an electron microscope or an optical microscope is 200 μm or less.

In the present invention, in particular, JIS-L1
Thickness under a load of 50 gf / cm ² conforming to H.096.
The case of 5 to 5 mm is preferred.

When the nonwoven fabric A is thinner than 0.5 mm, the amount of the exothermic powder composition held becomes small, the calorific value is small, and only short-time use is possible. Conversely, if it is thicker than 5 mm, the rigidity of the sheet-like heating element increases, and it is difficult to use it by attaching it to the body.

In the present invention, in particular, the nonwoven fabric C having an apparent specific gravity of 0.15 or less on the side contacting the heat-generating powder composition of the lower layer and the nonwoven fabric E having an apparent specific gravity of 0.15 or more as the upper layer are formed by the water jet method. Are preferred.

The nonwoven fabric D having an apparent specific gravity of 0.15 or less facilitates holding the exothermic powder composition, and the nonwoven fabric E having an apparent specific gravity of 0.15 or more has an effect of preventing the exothermic powder composition from leaking. .

In the present invention, a dry nonwoven fabric is particularly preferred as the nonwoven fabric A. The reason why the dry nonwoven fabric is preferable is that a nonwoven fabric having a small apparent specific gravity and a large pore size can be obtained.

In the present invention, nonwoven fabric B is particularly preferably produced by a wet papermaking method. The reason why the wet nonwoven fabric is preferable is that a uniform and dense nonwoven fabric can be obtained, so that the effect of preventing the exothermic powder composition from leaking is large, and a uniform sheet-like heating element can be obtained.

In the present invention, in particular, the JIS
The thickness at a load of 50 gf / cm ² according to -L1096 is preferably 0.5 mm to 5 mm. If it is thicker than 5 mm, it may feel uncomfortable when exercising when it is worn on the body, especially when it is put on underwear, and if it is thinner than 0.5 mm, there is no discomfort during use, but the relationship between the amount of the exothermic powder composition held The time available for use is short, which is not preferable except for a short use for a specific purpose.

The thickness of the sheet-shaped heating element can be adjusted to some extent by compressing the nonwoven fabric C after superimposing the nonwoven fabric C on the upper surface of the nonwoven fabric composite holding the heat generating powder composition.
Heating in this case is preferable because it has an effect of fixing the exothermic powder composition to the nonwoven fabric as well as a compressing effect.

In the present invention, any fiber may be used as the fiber constituting the nonwoven fabric, but artificial fibers such as acryl, polyester, polypropylene, vinylon and nylon and plant fibers such as pulp, cotton, hemp and rayon are preferred.

The non-woven fabric used in the present invention may be produced by any method, but is not limited to non-woven fabric A and non-woven fabric D.
Is a dry nonwoven fabric, nonwoven fabric B or nonwoven fabric E manufactured by a dry method capable of manufacturing a relatively low-density nonwoven fabric, a very uniform nonwoven fabric can be manufactured, and the density of the nonwoven fabric can be easily adjusted. A wet nonwoven fabric produced by the method is preferred.

The dry non-woven fabric is prepared by a spunbond method of forming a sheet directly from spun filaments, a melt-blowing method of drawing a molten polymer into fine fibers by applying hot air immediately after spinning, and a melt-blowing method of forming a sheet, or a pulp. It is manufactured by an air-laying method or the like in which the pulp fiber mat is formed by unraveling into a single fiber and the fibers are fixed to each other with a water-soluble binder or the like.

The wet papermaking method is a method in which fibers are dispersed at a low concentration in water, and a dispersing agent, a cohesive agent, a coagulant, a paper strength enhancer, a sizing agent, and the like are added as necessary. It refers to a method of producing a nonwoven fabric using a fourdrinier paper machine, an inclined paper machine, or a combination paper machine combining two or more paper machines. When the target nonwoven fabric is manufactured by the wet papermaking method, it is possible to obtain a nonwoven fabric having a very good fiber distribution uniformity, that is, a good texture.When such a nonwoven fabric is impregnated with an aqueous liquid, the distribution is more improved. It becomes uniform, and therefore, the degree of absorption of the aqueous liquid becomes more uniform.

In the production of the nonwoven fabric, a binder fiber other than the above-mentioned fibers, for example, a fiber having a binder function, may be used in combination to increase the strength of the nonwoven fabric or to sandwich the nonwoven fabric with the heat-generating powder composition. Heat compression is preferred. As binder fibers, heat-bonded fibers that are partially or entirely softened or melted by heat and fused with adjacent fibers, and vinylon that partially or entirely melts with hot water and bonds the fibers together when dried Binder fibers and the like are preferably used.

The manufactured nonwoven fabric is subjected to heat treatment, impregnation treatment with a urethane, acrylic, vinyl acetate, styrene-butadiene, starch, polyvinyl alcohol binder or the like so as to have desired properties, and calender treatment. Etc. may be performed. When the nonwoven fabric is manufactured by a wet papermaking method, a card method, a needle punch method, a spunlace method, or the like is used for the purpose of further increasing the strength of the nonwoven fabric by intertwining the fibers constituting the nonwoven fabric with each other. Post-processing (secondary processing) may be performed.

In the second invention, at least the upper side of the nonwoven fabric A
After the nonwoven fabric B is overlapped with the lower side and entangled by the water jet method, the exothermic powder composition is held on the upper surface of the nonwoven fabric A side, and the nonwoven fabric C is further superimposed on the upper surface of the exothermic powder composition. After heating and compressing with a hot embossing roll,
It is a sheet-like heating element obtained by impregnating with water or an aqueous liquid.

The heat-pressing with a hot embossing roll provides partial adhesion, so that the heat-generating powder composition does not become very dense. .

In the present invention, it is particularly preferable that the surface temperature of the hot embossing roll is 100 to 250 ° C.

If the surface temperature of the hot embossing roll is lower than 100 ° C., sufficient embossing effect and adhesive effect cannot be obtained.
If the temperature is higher than 250 ° C., the fibers constituting the nonwoven fabric are melted, so that the fibers stick to the surface of the embossing roll, causing cutting and dirt, resulting in poor operability. When fibers having a melting point higher than 250 ° C. are used, the strength of the nonwoven fabric is low, and cutting during operation is likely to occur.

In the present invention, the height of the convex portion of the hot embossing roll is particularly preferably 100 μm or more.

The height of the convex portion of the hot embossing roll is 100 μm.
m or more is sufficient for bonding the nonwoven fabric C to the nonwoven fabric composite comprising the nonwoven fabric A and the nonwoven fabric B. When it is smaller than 100 μm, the nonwoven fabric C and the nonwoven fabric composite are easily peeled off from the layer of the exothermic powder composition.

In the present invention, the linear pressure at the time of pressurizing the hot embossing roll is preferably 20 to 200 kg / cm.

When the linear pressure is less than 20 kg / cm, it is difficult to obtain an emboss effect, and the nonwoven fabric C and the nonwoven fabric composite are easily peeled off. If it is larger than 200 kg / cm, the convex portion of the hot embossing roll makes a hole in the nonwoven fabric C, and the exothermic powder composition easily leaks.

In the present invention, it is particularly preferable to add an adhesive powder to the exothermic powder composition.

Examples of the adhesive powder to be added to the heat-generating powder composition include powders such as polyethylene and polypropylene and modified products thereof. The effect of immobilizing the powder composition on the nonwoven fabric is improved. The preferred amount of the adhesive powder is 10 to 50% by weight of the exothermic powder composition. If the amount is small, the fixing effect is difficult to obtain, and if the amount is too large, the heating effect is reduced and the thickness of the sheet-shaped heating element is increased. .

The basis weight of the non-woven fabric B and the non-woven fabric E is preferably such that the thickness of the final sheet-shaped heating element is small for ease of use and large for preventing leakage of the heat-generating powder composition. Limited but generally 10 g / m ^{2 to} 100
g / m ² .

The person is small basis weight of the nonwoven fabric A and nonwoven fabric D is preferred, the lower limit for firmly holding the exothermic powder composition there is generally a ^{10g / m 2 ~200g / m 2} .

The method of holding the heat-generating powder composition on the nonwoven fabric composite may be any method. For example, a fixed amount of the heat-generating powder composition is sprinkled on a rotating hot embossing roll in a unit time, There is a method of dropping the embossing roll onto the nonwoven fabric composite and holding it, a method of continuously dropping a fixed amount of the nonwoven fabric composite per unit time from the slit-shaped opening, and a method of simultaneously applying vibration. It is more preferable to suction from the surface opposite to the surface on which the body composition is held.

The amount of the exothermic powder composition to be retained is usually about 200 g to 5000 g per m ² . 20
If it is less than 0 g, the heat generation time is short, and if it is more than 5000 g, the thickness of the sheet-like heating element increases and becomes heavy, so that it is not preferable except for a specific use.

The sheet-like heating element of the present invention may be selected in thickness, heating time, etc. according to the intended use. Pack and seal and store until used.

[0048]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.
In addition, "%, part" means "% by weight" and "part by weight".

Examples 1 to 10 The composition and physical properties of the nonwoven fabrics A, B and C are shown in Table 1.
To Table 10. The nonwoven fabric A and the nonwoven fabric B were entangled by a water jet from the nonwoven fabric B side under the conditions of a water pressure of 100 kg / cm ² and a speed of 20 m / min. Also, when the nonwoven fabric C was composed of the nonwoven fabric D and the nonwoven fabric E, the nonwoven fabric was entangled by water jet in the same manner as the nonwoven fabrics A and B.

In the wet papermaking method, a nonwoven fabric having a target thickness was prepared by appropriately adjusting a wet press part, a drying part, and a calendar part after forming the paper using a round paper machine.

As the nonwoven fabric of the dry method, a commercially available nonwoven fabric was used.

The obtained nonwoven fabric has a differential pressure of 15 mm from the opposite side.
The exothermic powder composition in which 90 parts of iron powder and 10 parts of activated carbon were mixed was dropped from the opening at a rate of 1100 g / m ² and held while sucking with H ₂ O. The nonwoven fabric C was overlaid on this nonwoven fabric, and heated and compressed by a mirror roll heating and pressing machine at 160 ° C. and a linear pressure of 40 kg / cm to form a sheet.

After cutting to 10 cm × 10 cm, 8.5% saline was sprayed at a rate of 520 g / m ² to produce a sheet-like heating element. This is stored in a flat, air-permeable bag made of a composite sheet of a microporous film made of polypropylene and a nylon nonwoven fabric on one side and a laminated sheet of a polyethylene film and a nylon nonwoven fabric on one side, and further sealed in a non-air-permeable bag.
After the day, the exothermicity was evaluated. Table 25 shows the results.

Example 11 A sheet-like heating element was prepared in the same manner as in Example 1, except that the spraying of the exothermic powder composition was carried out without suction. Table 25 shows the evaluation results.

Example 12 In Example 1, the nonwoven fabric C was applied on the held exothermic powder composition.
And a sheet-like heating element was prepared in the same manner except that the sheet-shaped heating element was compressed at a normal temperature of 20 ° C. at a linear pressure of 40 kg / cm by a mirror roll press. Table 25 shows the evaluation results.

Examples 13 to 23 Table 1 shows the composition and physical properties of the nonwoven fabrics A, B and C.
4 to Table 24. The nonwoven fabric A and the nonwoven fabric B were entangled by a water jet from the nonwoven fabric B side under the conditions of a water pressure of 100 kg / cm ² and a speed of 20 m / min. Also, when the nonwoven fabric C was composed of the nonwoven fabric D and the nonwoven fabric E, the nonwoven fabric was entangled by water jet in the same manner as the nonwoven fabrics A and B.

In the wet papermaking method, a nonwoven fabric having a target thickness was prepared by appropriately forming a wet press part, a drying part, and a calender part after papermaking using a round paper machine.

As the nonwoven fabric of the dry method, a commercially available nonwoven fabric was used.

A pressure difference of 15 mm was applied to the obtained nonwoven fabric from the opposite side.
A mixture of 80 parts of iron powder, 10 parts of activated carbon, and 10 parts of polypropylene particles (average particle size: 8 μm) was mixed with the exothermic powder composition at a rate of 1200 g / m ² while sucking with H ₂ O, and dropped from the opening. Was held. The nonwoven fabric C was superimposed on this nonwoven fabric, and heated and compressed by a thermocompression bonding machine using a hot embossing roll under the conditions shown in Tables 14 to 24 to form a sheet.

After cutting into 10 cm × 10 cm, 8.5% saline was sprayed at a rate of 520 g / m ² to produce a sheet-like heating element. This is stored in a flat, air-permeable bag made of a composite sheet of a microporous film made of polypropylene and a nylon nonwoven fabric on one side and a laminated sheet of a polyethylene film and a nylon nonwoven fabric on one side, and further sealed in a non-air-permeable bag.
After the day, the exothermicity was evaluated. The results are shown in Table 26.

Comparative Example 1 Tissue paper having a basis weight of 24 g / m ^2, a thickness of 1.9 mm, a basis weight of 57 g / m ² , and a porosity of 97.9 having the structure shown in Table 11.
% Of wood pulp nonwoven fabric (manufactured by Hapix Co., Ltd., J-soft) with ethylene-vinyl acetate based aqueous adhesive
It was applied in a halftone dot form at a rate of 0 g / m ² , and superposed while heating. 90 parts of iron powder, 8 parts of activated carbon,
1100 g / m2 of the exothermic powder composition containing 2 parts of a high molecular water retention agent
Spraying was performed at a rate of ² and vertical vibration was applied to hold. On this nonwoven fabric, a nonwoven fabric made of wood pulp having a thickness of 1.2 mm, a basis weight of 40 g / m ² , and a porosity of 97.5% (manufactured by Honshu Paper Co., Ltd.
Kinocloth), 200 ° C, linear pressure 40kg /
The sheet was heated and compressed by a roll thermocompression bonding machine to obtain a sheet.

After cutting to 10 cm × 10 cm, 8.5% saline was sprayed at a rate of 520 g / m ² to produce a sheet-like heating element having a thickness of about 2 mm. This was stored in an air-permeable flat bag and a non-air-permeable bag in the same manner as in Example 1, and the heat generation was evaluated two days later. Table 14 shows the results. (Japanese Patent Laid-Open No. 8
Additional example of -112303 publication)

Comparative Examples 2 and 3 Wet non-woven fabrics were prepared by mixing the fibers shown in Tables 11 and 12, and non-woven fabrics A and B and non-woven fabrics D and E were treated in the same manner as in Comparative Example 1 with an ethylene-vinyl acetate aqueous adhesive. And heated and superimposed. Thereafter, the exothermic powder composition is held in the same manner as in Example 1, the nonwoven fabric C obtained by laminating the nonwoven fabric D and the nonwoven fabric E is superimposed, and after heating and compression treatment, a saline solution is sprayed to produce a sheet-like heating element. As in Example 1, it was stored in a flat air-permeable bag and a non-air-permeable bag, and the heat generation was evaluated two days later. Table 25 shows the results.

COMPARATIVE EXAMPLE 4 Example 1 was applied to nonwoven fabric A with the structure shown in Table 13 without using nonwoven fabric B.
In the same manner as described above, the exothermic powder composition is held, the non-woven fabric C is superimposed, and after heating and compression treatment, a saline solution is sprinkled to produce a sheet-like exothermic body, which is stored in an air-permeable flat bag and a non-air-permeable bag. ,
Two days later, the exothermicity was evaluated. Table 25 shows the results.

In Tables 1 to 24, 2d × 5 mm means 2 denier and 5 mm in length.
E (core / sheath fiber of polypropylene / polyethyl acetate, manufactured by Daiwa Spinning Co., Ltd.), and PET fiber means polyester fiber.

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

[0069]

[Table 4]

[0070]

[Table 5]

[0071]

[Table 6]

[0072]

[Table 7]

[0073]

[Table 8]

[0074]

[Table 9]

[0075]

[Table 10]

[0076]

[Table 11]

[0077]

[Table 12]

[0078]

[Table 13]

[0079]

[Table 14]

[0080]

[Table 15]

[0081]

[Table 16]

[0082]

[Table 17]

[0083]

[Table 18]

[0084]

[Table 19]

[0085]

[Table 20]

[0086]

[Table 21]

[0087]

[Table 22]

[0088]

[Table 23]

[0089]

[Table 24]

[0090]

[Table 25]

[0091]

[Table 26]

Results: Of these sheet-like heating elements, those included in the present invention all had good heat-generating properties and did not cause any discomfort when worn on the body.
In particular, when the apparent specific gravity of the nonwoven fabric B is 0.15 or more and the apparent specific gravity of the nonwoven fabric A is 0.15 or less, particularly 0.10 or less, the holding property of the exothermic powder composition is good.

When the thickness of the sheet-like heating element is 0.5 to 5 mm, the mounting property is good. If the non-woven fabric A is a dry non-woven fabric, the exothermic powder composition has good retention and exothermic properties,
If the nonwoven fabric B is manufactured by a wet papermaking method, the holding property of the exothermic powder composition will be good.

In the case of Example 12 in which the nonwoven fabric C was overlaid on the exothermic powder composition held in the nonwoven fabric composite and then compressed at room temperature, the results were compared with those of Example 1 in which the heat compression treatment was performed. Thus, the heat-generating powder composition is slightly inferior in the holding property and the mounting property, but is sufficiently practicable.

The heat compression with the hot embossing rolls of Examples 13 to 19, 21, and 22 makes the exothermic powder composition more excellent in retention and heat generation than the heat compression with the mirror roll of Example 2. When the height of the protrusions of the hot embossing roll of Example 20 is smaller than 100 μm, and when the linear pressure of Example 23 is lower than 20 kg / cm, the exothermic powder composition retainability is equivalent to that of Example 2. However, the heat generation becomes good.

Among Comparative Examples 1 to 3 using a nonwoven fabric composite in which nonwoven fabrics are laminated with an adhesive as a material for holding the heat-generating powder composition, Comparative Examples 1 and 3 are slightly difficult to mount. Comparative Example 2 in which the thickness of the nonwoven fabric composite was reduced
In this case, the retention of the exothermic powder composition is poor. Comparative Example 4 using only the dry nonwoven fabric without using the nonwoven fabric composite is inferior in the holding property and the heat buildup of the exothermic powder composition.

The evaluation method was determined and evaluated as follows.

[Thickness of Non-woven Fabric and Sheet Heating Element] JI
Measured under a load of 50 gf / cm ² according to S-L1096.

[Holding property of exothermic powder composition] The ease of deviation of the exothermic powder composition in the sheet-shaped heating element and leakage from both sides and cut surfaces were visually determined. ：: No offset, no leakage. There is no deviation even if you shake it with your hands several times. ：: There is no deviation, no leakage, but there is a slight deviation if you shake it by hand several times. △ to 若干: Some deviation or leakage. Δ: Offset or leakage, but no continuous leakage. Δ to ×: one-sided or many leakages, but no continuous leakage. ×: One-sided or leaky, not practical use.

[Wearability] The heat-generating sheet housed in the air-permeable flat bag was affixed to the waist of the human body with an acrylic adhesive and was worn for 10 hours. ：: No discomfort. ○-△: Somewhat uncomfortable. Δ: Discomfort but no problem. Δ to ×: uncomfortable feeling, not enduring long-time use. X: The feeling of discomfort is large and it cannot withstand use for a short time.

[Heat generation] Measured according to JIS S-4100 in an atmosphere at room temperature of 20 ° C. and relative humidity of 65%. The number of test samples was 10 each, and the rise time required to raise the temperature from the start of heat generation to 40 ° C and the duration of 40 ° C or more were measured at four points in total by dividing the sample surface into four equal parts. Was evaluated. It should be noted that the duration is not necessarily required to be 10 hours or more because the duration may be short depending on the application. ：: All four locations have a rise time of 10 minutes or less and a duration of 10
More than an hour. △ to △: All four locations have a rise time of 10 to 20 minutes and a duration of 10 hours or more. Δ: Either the rise time was longer than 20 minutes at one place or less than 10 hours at one or more places. Δ to ×: One part has a rise time of more than 20 minutes and a duration of less than 10 hours. Or, the rise time is longer than 20 minutes at two or more locations. ×: The rise time is longer than 20 minutes and the duration is shorter than 10 hours at two or more places.

[0102]

As described above in detail with reference to Examples and Comparative Examples, according to the present invention, there is no problem of wearing on a human body, and a process of spraying and holding a heat-generating powder composition without a sense of incongruity. There is no problem in the manufacturing process such as maintaining a comfortable temperature for a long time,
It is possible to provide a sheet-like heating element.

Claims (14)

[Claims] 1. A heat-generating powder composition is held on a nonwoven fabric A side of a nonwoven fabric composite in which at least a nonwoven fabric A and a nonwoven fabric B are entangled by a water jet method. A sheet-shaped heating element, which is heated and compressed and then impregnated with water or an aqueous liquid. 2. The sheet-like heating element according to claim 1, wherein when the heat-generating powder composition is held by the nonwoven fabric composite, suction is performed from the surface opposite to the surface holding the heat-generating powder composition. . 3. The nonwoven fabric A has an apparent specific gravity of 0.15 or less and the apparent specific gravity calculated from the thickness at a load of 50 gf / cm ² in accordance with JIS-L1096 is 0.15 or less, and the nonwoven fabric B is 0.15 or more. The sheet heating element according to claim 1. 4. The sheet heating element according to claim 1, wherein an apparent specific gravity of the nonwoven fabric A is 0.10 or less. 5. The sheet according to claim 1, wherein the thickness of the nonwoven fabric A at a load of 50 gf / cm ² according to JIS-L1096 is 0.5 to 5 mm. Heating element. 6. A non-woven fabric D having an apparent specific gravity of 0.15 or less on the side where the non-woven fabric C comes into contact with the lower layer exothermic powder composition and a non-woven fabric E of an upper layer having an apparent specific gravity of 0.15 or more are entangled by a water jet method. The sheet heating element according to any one of claims 1 to 5, wherein the heating element is a sheet heating element. 7. The sheet-shaped heating element according to claim 1, wherein the nonwoven fabric A is a dry nonwoven fabric. 8. The sheet-shaped heating element according to claim 1, wherein the nonwoven fabric B is manufactured by a wet papermaking method. 9. The sheet heating element has a thickness of 0.5 to 5 m under a load of 50 gf / cm ² according to JIS-L1096.
The sheet-like heating element according to any one of claims 1 to 8, wherein m is m. 10. A sheet heating element according to claim 1, wherein the sheet heating element is heated and compressed by a hot embossing roll. 11. The surface temperature of the hot embossing roll is 100
The sheet-shaped heating element according to claim 10, wherein the temperature is in the range of from about 250 ° C. to about 250 ° C. 12. The height of the convex portion of the hot embossing roll is 10
12. The structure according to claim 10, wherein the thickness is 0 μm or more.
The sheet-shaped heating element according to the above. 13. The sheet heating element according to claim 10, wherein a linear pressure between the hot embossing roll and the roll is 20 to 200 kg / cm. 14. The exothermic powder composition according to claim 10, wherein the exothermic powder composition contains an adhesive powder.
Item.