JPH11206801A - Packaging material for heating element and heating element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress quality degradation due to heating loss by using a heat generating composition whose heat generating speed is controlled by free water in the production of a thin sheet heating element. SOLUTION: This is a flat packaging material 1 to enclose a heat generating composition which contains water and whose heat generating speed is controlled by free water, and the flat packaging material 1 has permeability at at least a part thereof and consists of a film- or sheet-form substrate 3 and a film- or sheet-form covering material 4, at least either of this substrate 3 and the covering material 4 having a water absorbing property and the water absorption of the water absorbing substrate 3 or the covering material 4 is 1 g/m<2> or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a process for manufacturing a heating element, wherein the exothermic reaction of the exothermic composition is remarkably suppressed by free water while the flat packaging material enclosing the exothermic composition is formed of a base material. And at least one of the base material and the coating material has a water absorbing property. After transferring and enclosing the heat-generating composition in a packaging material, the water content of the heat-generating composition is reduced. When the exothermic composition comes into contact with air by absorbing the part into the packaging material, the exothermic reaction proceeds rapidly, and the heating element packaging material capable of efficiently producing a heating element with extremely stable quality and a heating element. It relates to the heating element used.

[0002]

2. Description of the Related Art In recent years, as a so-called disposable color trouser, a flat bag made of a film or sheet base material having air permeability or air tightness and a film or sheet cover material having air permeability. A heating element in which a powdery heating composition is encapsulated in a body is widely used.

[0003] A heating element is also used in which an adhesive layer is formed on one side of the bag so that it can be directly adhered to underwear or the skin surface. It has also been proposed to use a warm compress by containing or carrying an agent or to use a so-called drug transdermal absorbent by containing or carrying a transdermally absorbable drug (Japanese Patent Laid-Open No. 2-149272). reference).

[0004] As a method of manufacturing the heating element, generally,
After dropping the exothermic composition on a predetermined area of the base material, cover the air-permeable coating material, and further thereafter, heat seal the base material and the periphery of the coating material over the entire circumference, using a hot-melt adhesive or the like. A sealing method is employed.

[0005] The heating element thus manufactured is sealed in an airtight outer bag, stored, or provided for distribution in order to suppress an exothermic reaction until use.

Conventional heat-generating compositions include a metal powder essential for an exothermic reaction, a carbon component such as carbon or activated carbon for promoting heat generation, and an oxide film on the surface of the metal powder to destroy the exothermic reaction. In addition to a metal chloride to be generated, a water retention agent such as wood flour, and the like, a powdery material containing an appropriate amount of water so that the exothermic reaction proceeds smoothly is used.

[0007] As in the prior art, a heat-generating composition in which each component such as metal powder and moisture is optimally blended is a porous body, has a large surface area, and has extremely low contact with air. Because of its good quality, an oxidation reaction, ie, an exothermic reaction, occurs immediately upon contact with air.

Therefore, while the exothermic composition is being blended at an appropriate compounding ratio, and until the exothermic composition is manufactured, dropped onto a base material, covered with a coating material and manufactured into a heating element. , An exothermic reaction occurs, causing a loss due to the exothermic reaction of the exothermic composition, deteriorating the quality of the exothermic composition, and solidifying a product generated by the exothermic reaction, causing various adverse effects. The adverse effects include, for example, variations in the amount of the exothermic composition dropped, a decrease in yield due to the removal of coagulated material, difficulty in handling, complicated maintenance of the manufacturing apparatus, operating hours of the manufacturing apparatus, This causes adverse effects such as restrictions on working hours and difficulty in coagulation treatment.

In order to solve such a problem, the present inventor has proposed that when the exothermic composition is made into a paste, the free water prevents contact between the exothermic substance and the air, that is, the free water acts as a barrier layer. During the production of the heat-generating composition, and during the production of the heat-generating composition, the paste-like heat-generating composition is manufactured, and this is laminated on a substrate by printing or coating such as screen printing, and then coated with a coating material. The exothermic reaction hardly occurs before the heating element is manufactured, thereby preventing loss due to the exothermic reaction of the exothermic composition and deterioration in the quality of the exothermic composition, and preventing solidification of the exothermic composition. You. For this reason,
It has been found that the yield and handleability are improved, the maintenance of the manufacturing equipment is easy, and there is no restriction on the operating time of the manufacturing equipment or the working hours of the workers. (Japanese Patent Application No. 8-177404).

In addition, the present inventor has proposed that when the amount of water in the exothermic composition is made excessive and the exothermic substance is coated with free water, the exothermic composition becomes free of exothermic substance even in a powder or flake exothermic composition. It has been found that it prevents contact with air, that is, free water exhibits a function as a barrier layer, and is extremely stable in air as in the case of a paste-like exothermic composition.

[0011]

When the exothermic composition is in the form of a paste, the exothermic composition is dense and has a small contact area with air, and free water functions as a reaction suppressing layer (barrier layer). As described above, there is almost no oxidation reaction with air until the heating element is manufactured and the obtained heating element is sealed in an airtight outer bag, so that the quality of the heating element is stable and its reliability is high. On the other hand, while the advantages such as an increase in the property are generated, if the barrier layer is not removed, the exothermic composition is stable when used, and the exothermic reaction does not easily proceed smoothly.

Further, even if the exothermic composition is in the form of powder or flakes, if the exothermic substance is coated with free water, the advantage that the exothermic composition in the form of paste is extremely stable in the air is produced, as in the case of the exothermic composition in paste form. On the other hand, if the barrier layer is not removed, the exothermic composition is stable during use and the exothermic reaction hardly proceeds smoothly.

Therefore, in the case of a heat-generating composition in which a heating substance is coated with free water, it is necessary to absorb a part of the water in the heat-generating composition into a packaging material to remove the barrier layer. Examples of the packaging material include those using a water-absorbing base material or a covering material.

In this case, although it depends on the components and proportions of the exothermic composition and the thickness of the transferred composition, it is necessary to remove the barrier layer of the exothermic composition and cause a smooth exothermic reaction by using the total water content in the exothermic composition. At least 1% by weight of the amount must be absorbed by the packaging material.

In order to absorb at least 1% by weight of the total water content in the heat-generating composition into the packaging material and to remove the barrier layer, the base material or the coating material having a water-absorbing property is measured by the measurement method described later. Must have a water absorption of 1 g / m ² or more.

By the way, in the conventional powdered heat-generating composition, since components such as metal powder and moisture are blended in an optimal state, when the moisture is absorbed by the packaging material, the absolute amount of the moisture is reduced. As a result, the required heat generation temperature and heat generation time cannot be obtained, and as a result, a material having no water absorption is used as the packaging material.

In a conventional heating element, a powdery heat-generating composition is interposed between a heat-sealing base material and a coating material, and the base material and the coating material are heated at the periphery of the heat-generating composition. Although the heat-sealing base material and the coating material are sealed, a polyethylene film or sheet is laminated on the inside of a non-woven fabric made of polyamide, polyester, or the like. A hydrophobic packaging material that does not absorb at all is used.

That is, in the conventional powdered heat-generating composition, each component such as metal powder and water is blended in an optimum state, and the exothermic reaction proceeds rapidly, and thus the barrier layer caused by free water is formed. As the packaging material used for the heat-generating composition, a material having no water absorption is used.

The present invention has been completed on the basis of the above technical findings, and the use of a heat-generating composition in which the rate of heat generation is suppressed by free water makes it possible to reduce the quality due to heat loss. In the manufacturing process of the sheet-like heating element, the disadvantage that the heat loss can be reduced to almost zero even in the presence of air is eliminated, and the heat-generating composition is enclosed in a packaging material comprising a base material and a coating material. Or at least one of the coating materials has water absorbency, and the exothermic reaction of the heating element at the time of use is prompt because the water absorption of the base material or the coating material having water absorbency is 1 g / m ² or more. It is an object of the present invention to provide a progressive heating element packaging material and a heating element using the same.

[0020]

According to the present invention, there is provided a packaging material for a heating element according to the present invention, in order to achieve the above-mentioned object, in which a heat-generating composition containing water and having a heating rate suppressed by free water is enclosed. The flat packaging material, the flat packaging material, at least a part thereof has air permeability, a film-like or sheet-like base material and a film-like or sheet-like covering material, the base material or At least one of the coating materials has water absorbency, and the base material or the coating material having water absorbency has a water absorption of 1 g / m ² or more.

The exothermic composition encapsulated in the exothermic packaging material of the present invention is not particularly limited as long as it contains water and the exothermic rate is controlled by free water. Or a powdery or flake-like heat-generating composition containing a substance or water and the heat generation rate is suppressed by free water. This type of exothermic composition will be described in detail in the description of the exothermic body according to the present invention.

In this kind of exothermic composition, since free water exhibits a function as a barrier layer, it is necessary to absorb a part of the moisture of the exothermic composition into the packaging material and remove the barrier layer. Examples of the water-absorbing packaging material include those using a water-absorbing base material and a covering material.

That is, the packaging material for a heating element according to the present invention has a flat shape, and is used for enclosing a heat-generating composition of this type, in which the rate of heat generation is suppressed by free water. , At least a portion of which has air permeability,
It is composed of a film-shaped or sheet-shaped base material and a film-shaped or sheet-shaped coating material, and at least one of the base material and the coating material has water absorption, and the water absorption of the water-absorbing substrate or coating material Is 1 g / m ² or more.

The heating element packaging material according to the present invention has a flat shape, and the flat packaging material uses a heat-generating composition that generates heat upon contact with air as a heat source. It is necessary to have.

In the heating element packaging material, at least a part of the packaging material means that at least one of the base material and the coating material constituting the packaging material has a ventilation property. In addition, when both the base material and the covering material are air-impermeable and the space between the base material and the covering material is air-permeable, that is, by partially sealing the outer peripheral portion of the packaging material to the side, Is configured to have air permeability.

The heating element packaging material according to the present invention has a portion that has air permeability, and the air permeability has a great effect on the control of the reaction rate or the exothermic temperature of the exothermic composition. In order to obtain an effect and to prevent low-temperature burns and ensure safety, it is preferable to manage the air permeability.
Further, in order to control the air permeability with high precision, it is preferable to control the air permeability of the film or sheet (base material and / or coating material) with the moisture permeability. Specifically, the moisture permeability is controlled by the Lissi method ( (Lyssy method L80-4000H type) 50-1
The range is generally 0.000 g / m ² · 24 hr, but is not particularly limited since it varies depending on the use and purpose of the heating element. In the case of a paste-like exothermic composition, the exothermic composition layer itself is formed with a stepwise reaction area with air, that is, the exothermic reaction with air causes the exothermic composition to gradually become porous and aerated. Since it has the function of controlling the air permeability, the range of management of the air permeability can be expanded as compared with the conventional powder heat generating composition.

When the base material and / or the covering material are composed of a plurality of layers of a breathable film, the moisture permeability as a whole is determined to be 50 to 10,000 g / m ² by the Lissy method.
-It is preferable to set the range to 24 hours.

If the water vapor transmission rate is less than 50 g / m ² · 24 hr, the calorific value becomes small and a sufficient heating effect cannot be obtained, which is not preferable. On the other hand, 10,000 g / m ² · 2.
Exceeding 4 hours is not preferable because the heat generation temperature becomes high to cause a problem in safety and a possibility that heat generation time may be shortened. That is, the moisture permeability of the breathable film (substrate and / or coating material) varies depending on the use of the heating element and the product design, and 100 to 10,000 g / m ² · 24 h for shoes.
r, and 100 for the body.
It is preferable to set it to １，1,000 g / m ² · 24 hr.

By the way, the Lissi method (Lyssy method) is a method conforming to industrial standards in various countries around the world.
In SZ0208, a temperature of 40 ° C. and a relative humidity difference of 90% R
H, it is set to 10
A measurement sample is inserted into the boundary between the lower chamber in a state of 0% relative humidity and the upper chamber in which a highly sensitive humidity sensor is installed, and the relative humidity of the upper chamber with the humidity sensor is adjusted to 10% RH (100% -90). %), And about ± 1% width (％ R
H), that is, the time required for the humidity to increase from about 9% to about 11% (several seconds) is measured and compared with the result of calibration performed under the same conditions using a standard sample whose transmittance is known in advance. This is a method of obtaining the transmittance.

In this case, in forming the heating element packaging material with the base material and the coating material, the air permeability of the entire or part of at least one of the base material and the coating material is within the above range. In addition to the case where the heating element packaging material is formed of a sheet, the lateral moisture permeability in the outer peripheral portion of the heating element packaging material formed of a non-permeable base material and a coating material is within the above range. It needs to be.

Further, a part of at least one of the base material and the coating material means that a part of the packaging material for the heating element has air permeability.

[0032] In the packaging material for a heating element of the present invention, the base material or the coating material constituting the packaging material has a water absorbing property and does not exude water when absorbing moisture in the exothermic composition. In addition, there is no particular limitation as long as the base material or the coating material has a water absorption of 1 g / m ² or more.

If the water absorption of the base material or the coating material constituting the packaging material is less than 1 g / m ² , the water absorption is insufficient, the removal of the barrier layer becomes insufficient, and the heat generation temperature in the early stage of use of the heating element. Is not preferable because the rising of the image becomes poor.

On the other hand, in the exothermic composition in which the rate of heat generation is suppressed by free water, if the amount of free water is too large, the absolute amounts of the heat generating substances and other components become insufficient, and the required heat generation time and heat generation temperature can be obtained. Disappears.

That is, in the case of the exothermic composition in the form of powder or flakes, if the amount of free water is excessively more than twice as large as the appropriate amount of water, the above-mentioned problems occur and the exothermic composition concerned However, it is not preferable because the liquor is liable to agglomerate, the flowability is deteriorated, and the amount dropped into the packaging material is more likely to vary.

In the case of a paste-like exothermic composition, if the viscosity is less than 50,000 cps by a measuring method described below, the transferability of the exothermic composition by printing, coating, or the like becomes poor, Free water becomes excessively large, the amount of exothermic substances and other components transferred becomes insufficient, the required exothermic time and exothermic temperature cannot be obtained, and the exothermic composition seeps out of a predetermined area on the substrate. Alternatively, a large amount of water must be absorbed by the substrate or the like after the transfer, and a substrate or the like having a special structure must be used, or the structure of the heating element needs to be complicated, which is not preferable.

In the exothermic composition in which the rate of heat generation is suppressed by free water, if the free water becomes excessive,
In order to remove the barrier layer of the exothermic composition, it is necessary that the base material or the coating material has a large water absorption, but in this case, the water absorption of the base material or the coating material becomes excessively large and the heat generation becomes excessive. It is important to take care not to absorb the water required for the exothermic reaction of the composition.

From the above viewpoints, in particular, when the water absorption of the base material or the coating material having a water absorbing property is extremely high, even if the water absorption amount of the base material or the coating material is extremely high, when the water content in the heat generating composition is absorbed, If the water required for the reaction is not absorbed, the upper limit of the water absorption is not particularly limited, but assuming that the transfer thickness is 0.1 to 1 mm, the range of the water absorption is
Generally, in the range of 5 to 1000 g / m ² , preferably 10
650 g / m ² , particularly preferably 12.5 to 5
It is desirable to be in the range of 50 g / m ² .

In the present invention, the water absorption of the base material or the coating material is a value measured by the following method. That is, the water absorption is
In the heat-generating composition, the heat-generating composition was a powdery heat-generating composition, which was measured on the basis of the condition of the optimum moisture regain, based on how much water was added. In other words, the basis of the measurement conditions is that when the moisture in the exothermic composition is absorbed, the component ratio is such that an optimal moisture content is obtained when the exothermic composition is in the form of a powder. The optimum moisture content was determined by experiment.

The water-absorbing base material or coating material may be any of non-breathable and breathable materials, regardless of whether the material itself has water absorbency or not. Is not particularly limited as long as it has water absorbency.

As the water-absorbing substrate or covering material, one or both sides of a non-breathable or breathable film or sheet on the side capable of absorbing moisture in the heat-generating composition may be used.
It is desirable to laminate a water-absorbing material having a water-absorbing property, thereby imparting the water-absorbing property and preventing the exudation of water.

Specific examples of the water-absorbing material include foamed films or sheets having water-absorbing properties (foams such as water-absorbing foamed polyurethane), papers, nonwoven fabrics and woven fabrics formed of fibers having water-absorbing properties. Or, in addition to nonwoven fabrics and woven fabrics containing water-absorbing fibers, or water-absorbing porous films or sheets, with or without water absorption, foamed films or sheets, nonwoven fabrics, woven fabrics or porous films or sheets Into, containing, impregnating, kneading, transferring or carrying a water absorbing agent to impart or increase water absorption, or this kind, cut the water absorbing material into its planar shape on which the exothermic composition is laminated, The cut pieces of the water-absorbing material are laminated and fixed on one or both sides (the inner surface of the packaging material) of a non-breathable or breathable film or sheet, and thereby, on one or both sides of the exothermic composition. That water absorption is imparted wants Te and the like.

The papers are not particularly limited as long as they are water-absorbing papers. Specific examples thereof include thin papers such as tissue paper, crepe paper, and kraft paper, liner papers and cardboards. Examples thereof include cardboard such as a core and a coated ball, or a laminate of one or more of these.

In the packaging material for a heating element according to the present invention, the joining portion between the base material and the coating material constituting the packaging material is bonded or adhered by heat bonding, heat fusion or hot melt type adhesive. However, it is desirable because there is no peeling during use and the quality is stable.

In the packaging material for a heating element according to the present invention, the base material and the coating material constituting the packaging material are not particularly limited as long as they have water absorption as described above. Generally, the base material and the coating material having water absorbency have no or almost no heat fusibility.

Therefore, in such a case, a hot-melt adhesive layer or a hot-melt pressure-sensitive adhesive layer is interposed at the outer peripheral edge of the exothermic composition laminated on the substrate. What is necessary is just to thermally bond or stick the material and the covering material. With such a configuration, the productivity is reduced and the cost of the base material and the coating material is increased. Therefore, it is desirable to use a heat-sealing base material and a coating material that can be thermally fused or bonded. Further, in the case of sealing by thermal bonding, it is necessary to use a heat-sealing base material and a coating material from the viewpoints of seepage of free water, sealing strength, and the like.

Specifically, for example, the water-absorbing substrate is a laminate comprising a heat-sealing nonwoven fabric, a water-absorbing nonwoven fabric, and a synthetic resin film or sheet (air-permeable or non-air-permeable film or sheet). Formed, when the heat generating composition is laminated on the heat sealable nonwoven fabric in the substrate, a part of the moisture in the heat generating composition permeates the heat sealable nonwoven fabric, migrates to the water absorbent nonwoven fabric, and is absorbed. As a result, the barrier layer caused by the free water disappears, so that the exothermic composition is always in a water state suitable for the exothermic reaction, and the exothermic reaction causes the water in the water-absorbent nonwoven fabric to be sequentially exothermic as the exothermic composition is consumed. , A stable exothermic reaction is obtained.

In the present invention, at least one of the base material and the coating material is provided with a nonwoven fabric which comes into contact with the exothermic composition. The nonwoven fabric comprises a heat-sealing nonwoven fabric and a water-absorbing nonwoven fabric. It is desirable that the heat-sealing nonwoven fabric be hydrophobic and the water-absorbing nonwoven fabric be hydrophilic because it exhibits excellent heat-sealing properties and water absorption.

Further, in the packaging material for a heating element according to the present invention, the base material or the coating material is a film or sheet obtained by laminating a heat-sealing nonwoven fabric and a water-absorbing nonwoven fabric from the viewpoint of heat sealing properties and water absorption. desirable.

The heat-sealable nonwoven fabric includes a composite nonwoven fabric of polyester and polyethylene. Specifically, for example, a laminated nonwoven fabric of polyester fiber and polyethylene fiber (“FULVALE” manufactured by Daiki Shoji Co., Ltd.) or a composite nonwoven fabric -Type spunbonded nonwoven fabric or other composite-type spunbonded nonwoven fabric [made by Asahi Kasei Kogyo Co., Ltd. (trade name: Full Veil), using heat-adhesive fibers].

Other heat-sealing nonwoven fabrics include
A fibrous core, and a nonwoven fabric formed of a double-structured fiber whose outer periphery is covered with a coating layer, wherein the core is formed of polyester fine fiber or polypropylene fine fiber; One in which the layer is formed of polyethylene is exemplified. An example of the nonwoven fabric formed of the fibers having the double structure is a spunbond nonwoven fabric (product name: ELEVES) manufactured by Unitika Ltd. Examples of the composite heat-bondable fiber having a double structure include UNK polypro fiber UC fiber manufactured by Ube Nitto Kasei Co., Ltd., and Chisso Polypro ES manufactured by Chisso Corporation.

Further, as another heat-sealing nonwoven fabric, a nonwoven fabric formed by using an ultrafine spunbond obtained by dividing a conjugate fiber in which polyethylene fibers are surrounded by ultrafine polyester fibers in the axial direction of the fibers is used. Examples of the ultrafine fibers include Spunbond (trade name: Alcima) manufactured by Unitika Ltd.

As a general packaging material for a heating element according to the present invention, a base material composed of three layers of A layer / B layer / C layer and a coating material composed of two layers of D layer / E layer is used. No. In this case, the layer A is a reinforcing layer, the layer B is a ventilation control layer and a seepage prevention layer, the layer C is a water absorbing layer, the layer D is a water absorbing layer, and the layer E is a breathable or non-breathable film or sheet.

The layer A is a so-called reinforcing layer and includes various nonwoven fabrics. The layer B is a layer for controlling air permeability and preventing the exothermic composition from seeping out. And a breathable film or sheet formed of a synthetic resin such as The C layer,
It is a layer having water absorbency and air permeability, and examples thereof include nonwoven fabrics formed of paper and water-absorbent materials such as pulp, cotton, and rayon.

The D layer may be the same as the C layer, and the E layer may be a permeable or non-permeable film or sheet made of a synthetic resin such as polyolefin or polyester. No.

Examples of the water-absorbent nonwoven fabric include a nonwoven fabric formed of a water-absorbent material such as rayon, pulp or cotton;
Alternatively, a nonwoven fabric formed of a composite nonwoven fabric formed of two or more of these water-absorbing materials may be used. On one side of these water-absorbent nonwoven fabrics, those obtained by further laminating a polyolefin resin film or the like become a water-absorbent laminate having no air permeability. By laminating a heat-sealing fiber non-woven fabric such as a resin non-woven fabric, a polyurethane-based non-woven fabric, and a polyester-based non-woven fabric, a breathable water-absorbent laminate having heat sealing properties can be obtained.

In the case of laminating a heat-sealable nonwoven fabric on this water-absorbent laminate, it is necessary to laminate the heat-absorbent nonwoven fabric on the water-absorbent nonwoven fabric side, and to laminate the base material and the coating material on the surface that can be thermally bonded during sealing.

The nonwoven fabrics such as the heat-sealing nonwoven fabric and the water-absorbing nonwoven fabric have a basis weight of 30% in order to exhibit required mechanical strength, heat sealing property and water absorption.
In the range of 5 to 500 g / m ² , more preferably 10 to 35 g / m ²
It is desirable to be in the range of 0 g / m ² .

The above-mentioned polyolefin resin film, polyester resin film or polyurethane resin film has a thickness of 5 to 500 μm in order to exhibit required mechanical strength and heat sealability.
m, more preferably 10 to 350 μm.

In the packaging material for a heating element according to the present invention, the following are preferred examples of the packaging material. That is, the base material is breathable, the coating material is non-breathable, or the base material is non-breathable, the coating material is breathable, or the base material and the coating material are non-breathable, The seal portion at the outer peripheral edge of the material is partially performed, there is a seal missing portion, and air flows from this defective portion,
And the like.

As the base material (generally non-permeable base material), one formed by laminating a water-absorbent nonwoven fabric, a non-breathable film, and a reinforcing nonwoven fabric in this order has an extremely excellent heat sealing property. In addition, the productivity of the heating element is remarkably improved, the water absorption is also remarkably excellent, and the mechanical strength is also excellent.

Other specific examples of the base material requiring heat-sealing properties include a non-woven fabric made of a heat-sealing fiber laminated non-woven fabric (ES fiber non-woven fabric) and a water-absorbing non-woven fabric.
Examples thereof include a laminated nonwoven fabric of a water-absorbing fiber and a heat-sealing fiber, a film or sheet formed of a polyolefin or polyester resin, and a reinforcing nonwoven fabric.

When the sealing portion is bonded by heat sealing, a resin layer having a higher melting point than the material of the sealing surface is required on the exposed surface (heat sealing roll side) of the adhesive layer. When bonding the seal portion, it is not always necessary. By the way, as the material of the reinforcing layer, polyethylene nonwoven fabric, polypropylene nonwoven fabric, polyester nonwoven fabric, rayon nonwoven fabric,
Paper etc. are mentioned.

As the non-woven fabric made of thermoplastic resin, in order to improve required mechanical strength and heat sealability,
It is desirable that the basis weight be in the range of 5 to 500 g / m ² , more preferably in the range of 10 to 350 g / m ² .

In the packaging material for a heating element according to the present invention,
Preferable examples of the coating material constituting the packaging material include the following.

That is, as a specific example of the coating material, a heat-sealing nonwoven fabric, a water-absorbing nonwoven fabric, a gas-permeable adhesive layer, a gas-permeable control film, and a reinforcing non-woven fabric are sequentially laminated. Can be In this case, the heat-sealing nonwoven fabric and the water-absorbing nonwoven fabric may be the same as those described above.

The air-permeable adhesive layer is an adhesive layer which does not impair the air permeability. Specifically, for example, an adhesive is applied on one side to control the air permeability of the polyolefin resinous porous film without impairing it. Or, apply a pressure-sensitive adhesive in a pattern coat or spray form and adhere a water-absorbent nonwoven fabric, and further on the other surface in the same manner as a reinforcing layer, on the exposed surface, polyester nonwoven fabric, polypropylene nonwoven fabric, nylon nonwoven fabric, rayon Nonwoven fabrics, cotton nonwoven fabrics, papers and the like may be used. When heat sealing property is required, a heat sealing nonwoven fabric is bonded by the same method instead of the water absorbing nonwoven fabric.

Further, examples of the heat-sealing fiber laminated nonwoven fabric (ES fiber nonwoven fabric) having a water-absorbing property include a laminated nonwoven fabric of a water-absorbing nonwoven fabric and a heat-sealing nonwoven fabric, and a blended nonwoven fabric of a water-absorbing fiber and a heat-sealing fiber. Can be

When the sealing portion of the packaging material is bonded by heat sealing, the air-permeable material formed of a resin having a higher melting point than the material of the sealing surface is formed on the exposed surface (heat seal roll side) of the polyolefin resin porous film or sheet. Although a certain layer is required, it may not be necessary when the sealing portion of the packaging material is bonded by an ultrasonic seal. As this material, polyethylene nonwoven fabric, polypropylene nonwoven fabric,
Examples include polyester nonwoven fabric, rayon nonwoven fabric, and paper.

A non-breathable or breathable film or sheet is used for the packaging material for a heating element according to the present invention.
The non-breathable or breathable film or sheet is not particularly limited as long as it is used for this kind of heating element, and preferably includes a film or sheet formed of a polyolefin-based resin.

The polyolefin resin film may be formed by using a usual molding apparatus and a usual molding method.
An inflation molding machine, a T-die molding machine and the like are suitably applied. In order to impart air permeability to the polyolefin resin film thus obtained, the film is stretched uniaxially or biaxially to form a porous film. The stretching may be performed by a conventional method using an ordinary stretching apparatus, and examples include roll stretching, simultaneous biaxial stretching, and sequential biaxial stretching.

In this case, as the polyolefin-based porous film, a polyolefin-based resin film is directly formed by uniaxial stretching or biaxial stretching, or a polyolefin-based porous film is obtained by stretching. The filler may be formed by eluting the filler with alkali, water, or the like.

In this stretching process, the stretching ratio is in the range of 100 to 800% in the case of uniaxial stretching, and 10 to 400% in the case of biaxial stretching. This is preferable from the viewpoints of the strength of the polyolefin-based porous film and the size of the through-hole, that is, the air permeability and the moisture permeability. In particular, in the case of uniaxial stretching, the stretching ratio is 10
If it is less than 0%, the stretched portion and the unstretched portion coexist and the stretching becomes non-uniform. On the other hand, if it exceeds 800%, the film may break during stretching, which is not preferable. In the case of biaxial stretching, if the stretching ratio is less than 10%, the stretched portion and the unstretched portion coexist, and the stretching becomes uneven. On the other hand, if the stretching ratio exceeds 400%, the film may break during stretching. Not preferred.

Examples of the polyolefin-based resin include polyethylene resins, polypropylene resins, and polyolefin-based resins such as ethylene-vinyl acetate copolymers. Among these, linear low-density polyethylene resins are particularly suitable for production and production of films. It is desirable because it is excellent in processability, the production cost is low, and the mechanical strength of the obtained porous film is large.

The above-mentioned polyolefin-based resins include those containing a filler. Examples of the filler include calcium carbonate, talc, clay, kaolin, silica, barium sulfate, kaolin sulfate, aluminum hydroxide, and zinc oxide. , Calcium oxide, titanium oxide, alumina, mica and the like.

The filler has an average particle diameter of 30 μm or less, and preferably in the range of 0.1 to 10 μm. If the particle diameter is too large, the through-holes become large, and conversely, it is too small. Aggregation occurs and dispersibility is poor, which is not preferable.

In addition, the linear low-density polyethylene resin porous film is improved in kneading and dispersing properties of the filler, in forming and processing, or in improving the functional strength of the film. For this purpose, an olefin terpolymer or a softener may be blended.

In the present invention, as described above, a filler and an olefin terpolymer or a softening agent may be blended with the linear low-density polyethylene resin. It is desirable that the filler is in the range of 100 to 300 parts by weight and the olefin terpolymer or softener is in the range of 5 to 100 parts by weight based on 100 parts by weight of the resin.

Further, the mixing of the linear low-density polyethylene resin, the filler and the olefin terpolymer or the softening agent does not require any special equipment, and a known mixer is used. In order to further improve the film formability, it is desirable to use a mixer such as a mixing roll, a Banbury mixer, a twin-screw kneader, or a Henschel mixer.

The thicknesses of the above-mentioned base material and coating material vary greatly depending on the application, and are not particularly limited. In general, it is desirable that both of them have a thickness of 10 to 1000 μm.

Each of the base material and the coating material has a thickness of 10 μm.
If it is less than m, the required mechanical strength cannot be obtained, and it may be difficult to make the film thickness uniform.

On the other hand, when the film thickness of each of the base material and the coating material exceeds 1000 μm, the flexibility is reduced, the conformability to the body surface is significantly reduced, and the followability to deformation and movement of the body surface is reduced. It is not preferable because it lowers, and the handle becomes stiff and the feeling becomes worse, and the thickness of the entire heating element increases.

The packaging material for a heating element according to the present invention is for enclosing a heat-generating composition containing water and suppressing the rate of heat generation by free water. Heat-sealing with a coating material over the outer peripheral portion of the heat-generating composition, an adhesive, sealing with an adhesive or a combination thereof prevents the heat-generating composition from falling off and scattering, preventing seepage from the seal portion, and the like. Desirable from a viewpoint.

Further, in the present invention, the packaging material, that is, the one in which the pressure-sensitive adhesive layer is laminated on the exposed surface of the base material or the covering material, is used for the heating element formed by using the packaging material for the heating element. It is desirable because it can be used for attaching to underwear and the like.

Examples of the pressure-sensitive adhesive layer include a layer formed of a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot-melt-type pressure-sensitive adhesive, or an aqueous gel.

As the aqueous gel layer, a layer formed of a polyacrylic acid-based aqueous gel is excellent because it has no skin irritation and is gentle on the skin.

Although the thickness of the pressure-sensitive adhesive layer is not particularly limited, it is 5 to 1000 μm, especially 10 to 5 μm.
When the thickness of the pressure-sensitive adhesive layer is less than 5 μm, the required adhesive strength may not be obtained, while the thickness of the pressure-sensitive adhesive layer is less than 5 μm.
If it exceeds, not only is it bulky and the feeling of use deteriorates, but also the economic efficiency deteriorates, which is not preferable.

By the way, if desired, this pressure-sensitive adhesive is
Other ingredients, such as other adhesives, tackifiers, anti-aging agents, fillers, tackifiers, tackifiers, colorants, defoamers, thickeners, modifiers, fungicides, antibacterial An appropriate amount of an agent, a bactericide, a deodorant, a deodorant, or the like may be appropriately added.
In addition, an appropriate amount of a herb, herb, or the like used such as a fragrance, lotion, emulsion, or aromatherapy may be appropriately mixed.

In order to achieve the above object, the heating element according to the present invention is characterized in that, when a heat-generating composition containing water and whose heat generation rate is suppressed by free water is enclosed in a flat packaging material,
As the flat packaging material, a heating element packaging material according to the present invention is used, and the heating element composition is encapsulated in the heating element packaging material.
The heat generating composition is characterized in that the base material and the coating material are joined at the outer peripheral edge.

That is, in the heating element according to the present invention, a powdery or flake-like or paste-like composition containing water and having a reduced heat generation rate by free water is used as the heat-generating composition. Therefore, in this state, almost no exothermic reaction occurs even if it comes into contact with air.

Therefore, when a heating element is manufactured using this kind of the heating composition, the water in the heating composition is absorbed by the packaging material for the heating element according to the present invention to remove free water (barrier layer). Although it is necessary to remove the water, it is necessary that the packaging material absorbs 1 to 60% by weight of the water content in the exothermic composition.

If the amount of water absorbed by the packaging material for the heating element is less than 1% by weight of the water content in the exothermic composition, free water remains, and the removal of the barrier layer becomes insufficient. It is not preferable because the rise of the heat generation temperature is deteriorated.

On the other hand, if the amount of water absorbed by the packaging material for the heating element exceeds 60% by weight of the water content in the exothermic composition, the moisture required for the exothermic reaction of the exothermic composition is insufficient, and the required exothermic temperature and exothermic time are required. Is not preferred because there is a possibility that the Further, in order to increase the amount of water absorption, the cost is increased due to the use of a special material, and the thickness of the water absorbing layer is required to be large. Further, as a method of dramatically increasing the amount of water absorption without increasing the thickness of the water-absorbing layer, a method of coating and kneading a water-absorbing polymer with a material or laminating a water-absorbing polymer fiber nonwoven fabric or the like can be used. As described above, by increasing the water absorption of the absorbing layer, the moisture ratio of the exothermic composition can be increased,
The viscosity of the exothermic composition at the time of transfer can be reduced to an appropriate viscosity with good production efficiency, and the productivity can be improved.

From the above viewpoints, it is particularly desirable that the amount of water absorbed by the packaging material for the heating element is 2.5 to 35% by weight, more preferably 5 to 30% by weight of the water content in the heat generating composition.

The absorptivity (k% by weight) of the moisture in the exothermic composition to the packaging material for the heating element was measured by the following method. After using a water-absorbing base material and a coating material used for this packaging material and punching it into a circular shape having a diameter of 65 mm, the temperature was 55 ° C.
It is dried for 24 hours under reduced pressure of mmHg to form a base material piece and a coating material piece, and each of the pieces is weighed. In this case, the weight of the base material piece is A ₁ (g), and the weight of the coating material piece is B ₁ (g).

Then, a diameter of 60 was placed on the dried substrate piece.
The exothermic composition is laminated by screen printing so as to have a circular shape of mm and a thickness of about 850 μm, and the weight A ₁ (g) of the base piece is subtracted from the total weight C (g) after lamination to generate heat. The lamination amount D (g) of the composition is determined. Assuming that the moisture content of the heat generating composition is P% by weight, the total water content (g) in the laminated heat generating composition is D × P / 100.

Further, after a dried coating material piece was laminated on the exposed surface of the heat-generating composition on the base material piece, an acrylic plate having a thickness of about 1 mm was placed thereon, and 2.5 kg of an acrylic plate was further placed thereon.
And leave it for 5 hours.

Thereafter, the base material piece and the coating material piece are peeled off, and the exothermic composition adhering thereto is almost completely removed with tweezers. Then, the weight of each of the base material piece and the coating material piece is reduced. Is measured. In this case, the weight of the base material piece is A ₂ (g), and the weight of the coating material piece is B ₂ (g).

Next, the base material piece and the coating material piece that have absorbed water are dried at a temperature of 55 ° C. under a reduced pressure of 1 to 2 mmHg for 24 hours, and the weight of each is measured. The weight of this substrate piece is A
₃ (g), and the weight of the coating material piece is B ₃ (g). K = [(A ₂ +
B ₂ ) − (A ₃ + B ₃ )] ÷ The value determined by D × 100 was defined as the water absorption.

The exothermic composition used in the present invention includes:
Examples thereof include powdery or flake-like powders which contain water and whose heat generation rate is suppressed by free water.

The components of the heat-generating composition are the same as those conventionally known, specifically, a heat-generating substance, a water-absorbing polymer and / or a thickener, a carbon component and a metal chloride. And water as an essential component, and further, if desired, a pH adjuster, an inorganic water retention agent, or the like, and the amount of water is excessive, and the rate of heat generation is suppressed by free water.

In this case, the solid components other than water are mixed in the same mixing ratio as before, and the water content is adjusted to 3 to 50% by weight, preferably 5 to 20% by weight from the state suitable for the exothermic reaction.
In excess.

The excess amount of water in the exothermic composition is 5% by weight.
If it is less than 10%, the amount of free water is insufficient, the suppression of the heat generation rate becomes insufficient, and the quality of the heat generating composition may deteriorate during the production of the heating element. As a result of being excessively large, the absolute amounts of the exothermic substance and other solid components are insufficient, and the required exothermic time and exothermic temperature cannot be obtained, which is not preferable.

In the case of the powdery or flake-shaped exothermic composition, if the amount of water is excessive, the exothermic composition is likely to clump in the hopper, and the fluidity becomes poor, so that the amount of the extruded composition to the substrate is reduced. In such a case, it is necessary to drop the exothermic composition onto the substrate while loosening the composition.

In the present invention, the paste-like heat-generating composition comprises a heat-generating substance, a water-absorbing polymer and / or a thickener, a carbon component and a metal chloride and water as essential components. Examples thereof include those formed in a paste form. In this case, if necessary, a pH adjuster, an inorganic water retention agent and the like may be further blended to form a paste as a whole.

The paste-like heat-generating composition is not particularly limited as long as it is composed of a component which reacts with oxygen in the air to cause an exothermic reaction and has a property of flowing when an external force is applied. is not.

[0107] Specifically, for example, those formed as a paste as a whole, including, as essential components, a heating substance, a water-absorbing polymer and / or a thickener, a carbon component and a metal chloride and water, are mentioned. The mixing ratio of the water-absorbing polymer is 0.1 to 7.5 with respect to 100 parts by weight of the heating substance.
0.1 to 10 parts by weight of a thickener and / or a thickener, 1.5 to 20 parts by weight of a carbon component and 1 to 10 parts by weight of a metal chloride as essential components, and water is blended. Examples thereof include those formed in a paste form. In this case, if necessary, furthermore, 0.01 to 10 parts by weight of a pH adjuster and 0.5 to 10 parts by weight of an inorganic water retention agent with respect to 100 parts by weight of the exothermic substance.
It is also possible to mix parts by weight and form a paste as a whole.

The exothermic composition is formed into a paste, as described above, and its viscosity (temperature: 20 ° C.)
In the following manner, generally, 50,000 to 9,500,0
If the viscosity of the heat-generating composition is too low, such as less than 50,000 cps, the transferability of the heat-generating composition by printing or coating becomes poor, or the water becomes extremely excessive, and the other heat-generating composition becomes extremely excessive. Insufficient amount of component transfer, short heating time, exothermic composition seeping out of predetermined area on substrate, need to absorb large amount of water after transfer to packaging material, special structure It is not preferable because it is necessary to use a wrapping material or to complicate the structure of the heating element. On the other hand, if it exceeds 9,500,000 cps, the transferability deteriorates, the amount of transfer varies, and the heat generation reaction on the surface occurs Is not preferred because of the possibility that

The viscosity is defined as R1 manufactured by Toki Sangyo Co., Ltd.
10 type viscometer, RE110U system, detection head RE
100U, controller RC100A) and SP
Using a P rotor, the number of rotations was 0.2 rpm (D = 0.4
(1 / S)) and a value measured at a measurement temperature of 20 ° C. This viscosity is a value at the time of transfer and lamination.

As another example of the paste-like heat-generating composition, there is a specification attached to the application filed on Jun. 17, 1996 by the present applicant (specification of Japanese Patent Application No. 8-177404).
(Ink-like or cream-like exothermic compositions).

When the heat-generating composition contains water and the rate of heat generation is suppressed by free water, the following various merits occur.

That is, since the exothermic composition is in the form of a paste, for example, thick coating printing, gravure printing, offset printing,
Printing using known printing techniques such as screen printing and spraying, and coating and coating with a head coater, roller, applicator, etc., are extremely easy to transfer and laminate, and produce ultra-thin heating elements at high speed. As compared with powdery or flake-like ones, since a non-uniform air layer is not included, measurement accuracy is remarkably improved, and the exothermic composition can be evenly distributed in the packaging material.

When the heat-generating composition is laminated on a substrate, the heat-generating composition has high penetration and anchoring properties, penetrates into the pores of these films or sheets, and prevents its movement and deviation. In addition, the contact area with air is remarkably small, the amount of supplied air is reduced, and almost no oxidation reaction occurs. As a result, it is more stable in air, loss due to exothermic reaction during production, deterioration of quality of exothermic composition and This is desirable because coagulation of the exothermic composition is further prevented.

In this case, if a part of the moisture in the exothermic composition is absorbed by the packaging material, free water is lost, and the exothermic composition becomes porous by absorbing the moisture into the packaging material. Thus, the contact with air becomes good, and a heating element having good heat generation characteristics can be obtained.

As the exothermic substance, an organic substance can be used, but iron powder which does not generate an off-odor due to the reaction can be used.
Zinc powder, aluminum powder or magnesium powder or an alloy powder composed of two or more of these metals, and further, a mixed metal powder obtained by mixing two or more of these are used. Among them, it is desirable to use iron powder which is the best in terms of safety, handling, cost, storage stability and stability.

As the water-absorbing polymer, mainly,
A polymer material that absorbs water and an aqueous solution of a metal chloride smoothly and in large amounts can be mentioned. Specifically, for example, a self-cross-linked polyacrylate disclosed in JP-B-54-30710, The reaction product of a polyvinyl alcohol-based polymer and a cyclic anhydride disclosed in Japanese Unexamined Patent Publication No. Sho 54-20093, and a crosslinked polyacrylate disclosed in Japanese Unexamined Patent Publication No. 59-84305 can be used. Yes, these may be treated with a surfactant, or a surfactant may be combined with these to improve the hydrophilicity. Among these water-absorbing polymers, there are those that absorb water or an aqueous solution of a metal chloride to increase the viscosity,
It mainly has a function of smoothly absorbing a large amount of water or an aqueous solution of a metal chloride.

Good examples of commercially available water-absorbing polymers include Sunfresh ST-30MP manufactured by Sanyo Chemical Industries.
S, ST-100MPS, ST-500MPS, etc.
It is particularly preferable because it rapidly absorbs water and an aqueous solution of a metal chloride and has a high absorption amount.

Examples of the thickener include substances which absorb water or an aqueous solution of a metal chloride to increase the consistency or impart thixotropy. Bentonite, stearate, polyacrylic acid and the like can be used. Polyacrylates such as soda, gelatin, polyethylene oxide, polyvinyl alcohol, polyvinylpyrrolidone, gum arabic, tragacanth, locust bean gum, guar gum, gum arabic, alginates such as sodium alginate, pectin, carboxyvinyl polymer,
Starch-based water-absorbing agents such as dextrin, pregelatinized starch, and processing starch; polysaccharide-based thickening agents such as carrageenan and agar; CM
C, a cellulose derivative-based thickener such as ethyl acetate, hydroxyethyl cellulose, methyl cellulose or hydroxypropyl cellulose, an acrylic sulfonic acid-based polymer (for example, Nippon Shokubai Co., Ltd., trade name: CS-6HS), a water-soluble cellulose ether Or one or two selected from poly-N-vinylacetamide and the like.
Mixtures of more than one species may be mentioned, and these may be further treated with a surfactant, or a surfactant may be combined with these to improve the hydrophilicity. These thickeners mainly have a function of absorbing water or an aqueous solution of a metal chloride to increase the consistency or impart thixotropy.

The above-mentioned water-soluble cellulose ethers include
Specifically, for example, methyl cellulose obtained by etherifying cellulose with a methoxyl group (manufactured by Shin-Etsu Chemical Co., Ltd.
Product name: Metroze SM15, Metroze SM25, Metroze SM400, Metroze SM4000, etc.),
Hydroxypropyl methylcellulose obtained by etherifying cellulose with a hydroxypropoxyl group (trade names: Metrolose 60SH-50, Metrolose 60SH-4000, Metrolose 90SH-40, manufactured by Shin-Etsu Chemical Co., Ltd.)
00, Metros 90 SH-30000, Metros 9
Water-soluble cellulose ether such as hydroxyethyl methylcellulose obtained by etherifying cellulose with a hydroxyethoxyl group (trade name: Metroose 60SH-50, manufactured by Shin-Etsu Chemical Co., Ltd.).
Metroose 60SH-4000, Metroose 90SH-
4000, Metrolose 90SH-30000, Metrolose 90SH-100000), water-soluble cellulose ethers such as Cellogen EP, Cellogen BSH-12, Cesca MC, Cesca MHEC, and Cesca MHPC manufactured by Daiichi Kogyo Seiyaku.

Examples of the carbon component include carbon black, graphite and activated carbon. Examples of the metal chloride include alkali metal chlorides such as sodium chloride and potassium chloride and alkali chlorides such as calcium chloride and magnesium chloride. An example thereof is chloride of earth metal.

The packaging material for a heating element according to the present invention is for enclosing the exothermic composition. The base material and the coating material constituting the packaging material are sealed over the outer periphery of the exothermic composition. Is being worn.

Next, an example of manufacturing a heating element using the base material and the covering material that constitute the packaging material for the heating element according to the present invention will be described. First, the step (A) of producing a heat-generating composition containing water and suppressing the heat generation rate by free water is performed.

As the exothermic composition, the same ones as described above can be used. By the way, in producing the paste-like exothermic composition, all the components are put into a mixer and then may be mixed uniformly, or alternatively, only the solid component of the all components may be mixed. After being charged into the mixer, the components are uniformly mixed with this mixer, and then water or an aqueous solution or dispersion of a metal chloride is charged and mixed. An exothermic composition may be obtained. In this case, first
Each of the solid components is charged into a mixer, and then uniformly mixed, and then water is charged and mixed, so that a paste-like exothermic composition with excellent quality is obtained, which is desirable.

The mixer is not particularly limited as long as it can uniformly mix the components constituting the exothermic composition. Specific examples include a ribbon mixer, a spartan mixer, a screw blender, and a roll mixer. Known examples include a mixer, a Banbury mixer, and a kneader.

In the present invention, the step (B) of dropping or transferring the exothermic composition obtained in the step (A) to at least one predetermined region on the upper surface of the substrate and stacking the same is performed.

As the base material used here, the above-mentioned ones can be mentioned, but they are omitted here to avoid repeated explanation.

In this step (B), the exothermic composition is laminated on the upper surface of the base material by printing, coating or dropping, such as screen printing. It may be stacked at two or more places, or may be stacked in a staggered manner in the longitudinal direction of the base material.

In the present invention, a step (C) of covering a gas-permeable covering material so as to cover the heat-generating composition is performed.

As the covering material used here, the same as the above-mentioned covering material can be mentioned, and therefore, it is omitted here to avoid redundant description.

In the present invention, the exothermic composition is laminated on the base material, and the covering material is placed thereon, and the outer peripheral portion of the exothermic composition is thermally bonded, thermally fused or hot melted. It is desirable to seal by adhesion with a system adhesive.

In the packaging material for a heating element according to the present invention, since it is a packaging material for a heating element that generates heat by contact with air, at least a part of this packaging material has air permeability.

When a part of the moisture in the exothermic composition is absorbed by the packaging material, the barrier layer is lost, and the exothermic composition becomes porous and becomes in good contact with air. The temperature characteristics at the time become better.

[0133]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings, but the present invention is not limited thereto.

Example 1 The heating element shown in FIG. 1 was formed using the packaging material for a heating element according to the first example of the present invention. That is, this heating element encloses a paste-like heating composition 2 in a rectangular packaging material 1 having a length of 116 mm and a width of 86 mm.
A part of the moisture contained therein is absorbed by the water-absorbing layer of the packaging material 1 so that the barrier layer is lost, whereby the heat-generating composition 2 becomes porous and has good contact with air. In this case, the packaging material 1 is a non-breathable substrate 3
And a covering material 4 having air permeability.

The base material 3 is made of a nonwoven fabric layer 3a made of a hydrophobic and heat-sealable polyester fiber and polyethylene fiber (manufactured by Unitika Co., Ltd., trade name: Alsima A0504WTO, basis weight: 50 g / m) so as to obtain sufficient flexibility.
m ² ), a composite laminated non-woven fabric of a water-absorbent cotton non-woven fabric 3b (product name: Alcima cotton entangled product AC5050, manufactured by Unitika Ltd., basis weight 50 g / m ² ), an exposed surface for reinforcing material and heat sealing. Polyester non-woven fabric with high melting point (manufactured by Shinwa, trade name 7830, basis weight 30 g / m
² ) A non-breathable laminated film obtained by sand laminating 3d with a polyethylene resin having a thickness of 40 μm was used.

The covering material 4 is used as a reinforcing material to increase the mechanical strength and to obtain sufficient heat resistance at the time of heat sealing.
m ² , polyester non-woven fabric (manufactured by Shinwa, trade name 783)
0) 4a and a 40 μm thick polyethylene porous film 4b (trade name: ESPOIR N, manufactured by Mitsui Toatsu Co., Ltd.) 4b in a pattern of an adhesive portion 1 mm and a non-adhesive portion 1 mm at an angle of 45 ° with styrene-isoprene-styrene. After bonding and laminating the entire surface with a block copolymer hot-melt adhesive (trade name: Despomelt PT-3, manufactured by NSC, Inc.), use the same bonding method (however, the bonding pattern is perpendicular to the previous angle). Crossing), basis weight 50g /
m ² , hydrophilic / water-absorbent cotton nonwoven fabric 4c, basis weight 50
g / m ² , a hydrophobic and heat-sealable polyester fiber / polyethylene fiber composite type spunbond nonwoven fabric (product name: Alcima A0504WTO, manufactured by Unitika Ltd.) Product AC5050) 4d was used. The moisture permeability of the coating material 4 was 400 g / m ² ··· by the Lissi method.
24 hours.

In the present invention, a paste-like heat-generating composition 2 to be described later is laminated on a predetermined position on the heat-sealable composite nonwoven fabric 3a of the base material 3 by screen printing. The covering material 4 is covered so that the heat-sealable composite nonwoven fabric 4d in the above-mentioned method comes into contact with the paste-like heat-generating composition 2.
Is heat-sealed at the outer peripheral portion of the base material 3 and the coating material 4, and a part of the moisture in the heat-generating composition 2 is removed by the cotton nonwoven fabric 3 b of the base material 3 and the cotton nonwoven fabric 4 c of the coating material 4 The exothermic composition 2 is made porous so that the contact with the air is improved.

The paste-like exothermic composition 2 was produced by the following method. That is, iron powder which is a heating substance
(DKP manufactured by Dowa Tekko Co., Ltd.) 100 parts by weight of CMC (Cerogen EP, manufactured by Daiichi Kogyo Co., Ltd.) as a thickener
1.2 parts by weight, 0.3 parts by weight as a water-absorbing polymer (manufactured by Sanyo Chemicals Co., Ltd., Sun Fresh ST-500MPS), and 3.0 parts by weight of bentonite (manufactured by Hoyo Bentonite Co., Ltd., Yutaka 300) as an inorganic thickener Parts, activated carbon (SA-Super manufactured by Norit) 8.0 parts by weight, 4.0 parts by weight of sodium chloride as a metal chloride, 0.15 parts by weight of calcium hydroxide as a pH adjuster, and 34 parts by weight of water. It is kneaded and adjusted.

That is, the mixing ratio was determined by using activated carbon, a thickener,
Water absorbent polymer, bentonite, sodium chloride, PH
In the order of the adjusting agent, a mixing machine (T.K.
K. (Hivis Mix 2P-100 type, capacity 100 liters), stir for 5 minutes, add water while stirring, knead for 10 minutes, add iron powder and knead for 5 minutes, then clean off deposits in container And kneading again for 15 minutes, followed by discharging. The viscosity of the paste-like exothermic composition obtained is around 3.03 million cps and the specific gravity is 2.63 g / cc.
Met.

The exothermic composition in paste form was heated at 20 ° C. for 1 hour.
When stored for a long time, the viscosity increases, but when kneaded again, the viscosity is 3.07 million cps by the following measurement method, and this was laminated on the base material 3 by screen printing. The rotation speed of the blade in this case is 15 rp from start to end.
m.

The viscosity was measured by Toki Sangyo Co., Ltd. (R
110 type viscometer, RE110 system, detection head RE
100U, controller RC100A) and SP
Using a P rotor, the number of rotations was 0.2 rpm (D = 0.4
(1 / S)) and a value measured at a measurement temperature of 20 ° C.

The exothermic composition 2 is in the form of a paste, has a small surface area, and has a limited contact area with air. In addition, the free water functions as a barrier layer for suppressing the contact between iron powder and air, so that the composition per unit time can be improved. As a result, the amount of oxidation per unit is significantly restricted, and as a result, the oxidation reaction until the heating element is obtained is almost prevented by laminating with a film-like or sheet-like coating material.

In Example 1, as described above, the paste-like heat-generating composition 2 was coated on the substrate 3 with a thickness of 400 mm.
Laminating is performed by screen printing using a screen plate having a thickness of μm, and a coating material 4 is placed thereon. The base material 3 and the coating material 4 are heat-sealed at the outer periphery of the heat generating composition 2.

That is, in this embodiment, while the roll film-like substrate 3 having a width of 120 mm is fed horizontally, the paste-like heat-generating composition 2 is screen-printed on the upper surface thereof with a rotary screen plate having a thickness of about 400 μm. Ultra-thin heating elements were manufactured by cutting one after another by die cutting so that the seal width L around each of the heating elements was 8 mm by heat sealing.

Each of the cut heating elements is subsequently sent to a packaging step and sealed in an airtight outer bag (not shown).

The paste-like exothermic composition 2 is screen-printed on the upper surface of the base material 3 and then a part of the water is gradually absorbed by the base material 3. Coated. However, the paste-like exothermic composition 2
The time from screen printing on the base material 3 to encapsulation in the outer bag is extremely short, during which the moisture of the paste-like exothermic composition 2 is reduced to such an extent that an exothermic reaction is possible. Is hardly absorbed by

Therefore, there is no possibility that heat generation of the paste-like exothermic composition 2 occurs in the manufacturing process, and there is no risk of loss due to the exothermic reaction in the manufacturing process or deterioration of the exothermic composition 2 at all. Further, in the process from the mixing of the paste-like heat-generating composition 2 to the screen printing on the base material 3, there is almost no possibility that the paste-like heat-generating composition 2 solidifies due to an exothermic reaction, the yield decreases due to the solidification, the operation is interrupted, It is possible to prevent various adverse effects such as restrictions on operation time, difficulty and danger of cleaning the manufacturing apparatus, frequent cleaning of the manufacturing apparatus, and difficulty in coagulation treatment.

By the way, before the heating element is sealed in the air-impermeable bag and reaches the user's hand through distribution, the free water in the paste-like heating composition 2 is absorbed by the base material 3 and the coating material 4. Since the moisture content ratio is suitable for obtaining a predetermined heat generation temperature, the quality of the heat generation composition 2 does not deteriorate until the air-impermeable bag is broken and comes into contact with air. In addition to maintaining the quality of No. 2 at a high level, the exothermic reaction is started immediately after the non-breathable bag is broken and the heating element is taken out, and the temperature is quickly raised to a predetermined exothermic temperature.

[0149] After 24 hours had passed after enclosing in the outer bag, the outer bag was broken and the surface of a human body was subjected to normal use. When the temperature rose to about 38 ° C in about 1 minute. , Then 3
An exotherm occurred at 8-41 ° C. for about 4 hours. During this use, the exothermic composition 2 was completely fixed to the substrate 3, and an average heat generation was observed over the entire surface.

By the way, this paste-like exothermic composition 2
Was measured by the above-described method to find that the water absorption rate (K wt%) of the water was 3.0 wt%.

Example 2 Example 2 was the same as Example 1 except that the method of bonding the seal portion was changed from heat sealing to ultrasonic sealing and the configuration of the base material 3 and the coating material 4 was changed. It is manufactured in.

That is, as the base material 3 and the coating material 4, the heat seal layer 3 of the base material 3 and the coating material 4 in Example 1 was used.
a, Instead of the water-absorbing layer 3b, blended non-woven fabrics 3a, 3b of 50% polyester fiber and 50% rayon fiber (Soflon-EOH-80, trade name, manufactured by Unitech Co., Ltd., basis weight 80 g /
m ² ) was used.

That is, in order to increase the mechanical strength as a reinforcing material and obtain sufficient flexibility, a polyester nonwoven fabric (trade name: 783, manufactured by Shinwa Co.)
0 basis weight 30 g / m ² ) 4a and a polyethylene porous film (trade name: ESPOIR N, manufactured by Mitsui Toatsu Co., Ltd., thickness: 40)
μm) 4b and 45
After bonding and laminating with a hot-melt adhesive of styrene-isoprene-styrene block copolymer (trade name: Despomelt PT-3 manufactured by Nippon NSC) at an interval of 1 mm and 1 mm non-adhesion at an angle of 1 degree, one surface thereof Further, by the same bonding method (however, the angle of the bonding pattern intersects at right angles with the previous time), a blended nonwoven fabric of 50% 4d of 60 g / m ² polyester fiber and 50% 4c of rayon fiber is sequentially laminated. A laminated film was used. This sealing method
Performed with an ultrasonic seal. The moisture permeability of this coating material is
It was adjusted to 400 g / m ² · 24 hr by the Lissi method.

Incidentally, the paste-like exothermic composition 2 was prepared in Example 1.
The description is omitted because it is the same as.

By the way, this paste-like exothermic composition 2
Was measured by the method described above, and was found to be about 3.0% by weight.

Embodiment 3 The heating element shown in FIG. 2 is formed using the heating element packaging material according to the embodiment of the present invention.

[0157] In Example 1, except that the method of bonding the seal portion was changed from heat sealing to bonding with an adhesive, the configuration of the base material 3 and the coating material 4 were changed, and the adhesive layer was provided. Same as 1.

As the substrate 3, the reinforcing layer 3d of the substrate 3 in Example 1 was omitted, and instead of the water absorbing layer 3b, a basis weight of 40 g was used.
/ M ² rayon non-woven fabric 3b (trade name 714, manufactured by Shinwa)
0) was used.

That is, the base material 3 is made of a hydrophilic / water-absorbing rayon non-woven fabric (trade name: 7140, manufactured by Shinwa Co., Ltd., weight: 40 g / m ² ) 3b so that sufficient flexibility can be obtained. A laminated film formed by laminating a non-breathable polyethylene film layer 3c having a thickness of 40 μm was used.

[0160] As the substrate 3, the exposed surface of the substrate 3
A heating element was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive layer 5 and the release paper 6 were laminated.

The coating material 4 is made of a polypropylene nonwoven fabric 4a in place of the coating material 4a in Example 1.
4b used the same thing as Example 1, and used rayon nonwoven fabric 4c instead of 4c of Example 1.

That is, in order to increase the mechanical strength and obtain sufficient flexibility, the coating material 4 is made of a polypropylene nonwoven fabric (RC2040 (trade name, manufactured by Idemitsu Petrochemical Co., Ltd.)) that functions as a reinforcing material from the outside. Basis weight 40
g / m ² ) 4a, and 4
At an angle of 5 degrees, at an interval of 1 mm of the bonded part and 1 mm of the non-bonded part,
Alternately using a styrene-isoprene-styrene block copolymer hot melt adhesive (trade name: Despomelt PT-3, manufactured by NSC) and a polyethylene porous film (trade name: Espoar N, manufactured by Mitsui Toatsu) thickness 4
After bonding and laminating 4b with 4b, a hydrophilic / water-absorbing rayon non-woven fabric (manufactured by Shinwa Co., Ltd.) Name 7160 basis weight 60g / m ² ) 4
c) was used. The moisture permeability of the coating material 4 was 400 g / m ² · 24 by the Lissi method.
hr.

In other words, in this embodiment, while the roll film-like substrate 3 having a width of 120 mm is fed horizontally, the paste-like heat-generating composition 2 is screen-printed on the upper surface thereof with a rotary screen plate having a thickness of about 400 μm. On top of that,
A hot melt adhesive of a styrene-isoprene-styrene block copolymer system is spray-coated over the entire surface at a basis weight of 9 g / m ² , the covering material 4 is covered, the seal portion is pressure-bonded, and further adhered to the outer skin. Was formed with a styrene-isoprene-styrene block copolymer-based pressure-sensitive adhesive (trade name: JM6028, manufactured by Fuller Japan Co., Ltd.).

Embodiment 4 The heating element shown in FIG. 3 is formed using the heating element packaging material according to the embodiment of the present invention.

That is, a shoe insole-shaped heating element having a length of 22 cm and a width of 7 cm was manufactured by the following method. Corrugated cardboard liner paper (brand name NS liner manufactured by Nippon Paper Industry Co., Ltd.)
A material obtained by laminating a non-breathable polyethylene resin to a thickness of 40 μm on a basis weight of 200 g / m ^{2 and a} water absorption of 100 g / m ² ) 3b was used.

As the covering material 4, from the outside, a polypropylene nonwoven fabric (trade name: RC manufactured by Idemitsu Petrochemical Co., Ltd.) was used as a reinforcing material.
2040 basis weight 40 g / m ² ) 4a and polyethylene porous film (trade name PORAM PN-3 manufactured by Tokuyama Corporation)
0 Thickness 30 μm) 4b was bonded to the bonded portion 1 mm and the non-bonded portion 1 mm at an angle of 45 ° with respect to the flow direction over the entire surface.
After bonding and laminating with a styrene-isoprene-styrene block copolymer-based hot melt adhesive (trade name: Despomelt PT-3, manufactured by NSC), a hydrophilic / water-absorbing material was further applied to the polyethylene porous film 4b side. Crepe paper (brand name bleached crepe paper manufactured by Tokai Pulp Co., Ltd.)
The basis weight of 50 g / m ² ) 4c was used.

Using a screen plate having a thickness of about 800 μm except the outer peripheral portion having a width of 8 mm on the base material 3, a paste-like heat-generating composition 2 to be described later is laminated in a shoe insole shape by screen printing. Spray-coated a styrene-isoprene-styrene block copolymer-based hot melt adhesive (trade name: Despomelt PT-3 manufactured by NSC) at a basis weight of 9 g / m ² over the entire surface,
After covering and adhering the covering material 4 from above, punching by die cutting, and sealingly packaging with a non-breathable outer packaging material.

After packaging with the outer wrapping material, a part of the moisture of the exothermic composition is gradually absorbed by the water absorbing layer of the wrapping material, and the barrier layer is lost. As a result, the exothermic reaction proceeds rapidly by contact with air. The initial heat generation is very fast, and after about 3 hours of heating at a relatively high temperature, the temperature drops, softens, and heats up for another 2.5 hours, so that a low-temperature burn can be prevented and a highly safe heating element can be obtained. Was. The moisture permeability of the coating material 4 was 2000 g / m ² · 24 hr by the Lissi method.

This paste-like exothermic composition 2 was produced by the following method. That is, with respect to 100 parts by weight of iron powder (DKP manufactured by Dowa Iron Powder Co., Ltd.)
1.2 parts by weight of CMC (Cerogen EP manufactured by Daiichi Kogyo Co., Ltd.) as a thickener and bentonite (brand name of Yuyo 300 manufactured by Hoyo Bentonite) 3.0 as an inorganic thickener
Parts by weight, activated carbon (trade name: SA-SUPE, manufactured by Norit)
r) 7.5 parts by weight, 4.0 parts by weight of sodium chloride as a metal chloride, 0.2 parts by weight of calcium hydroxide as a pH adjuster and 32 parts by weight of water were added to obtain Exothermic Composition 2. The viscosity was about 7 million cps at a temperature of 20 ° C.

By the way, the base material 3 and the coating material 4 were thermally bonded with a styrene-isoprene-styrene block copolymer-based hot melt adhesive in the same manner as in Example 3.

When the obtained heating element was stored in a non-breathable outer bag, opened after 24 hours and used, an excellent heat state was obtained within 60 seconds, and the entire sole was over 3.5 hours. After heating at a comfortable temperature and the temperature of the sole increased, the exothermic temperature was lowered slightly for safety and continued to be generated for another 2 hours.

Example 5 In Example 4, in place of the crepe paper 4c of the covering material 4, a coated ball 4c was formed as a single layer serving as a water-absorbing layer, and the substrate 3 was the same as that in Example 4, that is, A cardboard liner paper (manufactured by Nippon Paper Industries, trade name: NS liner, basis weight: 200 g / m ^2, water absorption: 100 g / m ² ) 3b is laminated with a non-breathable polyethylene resin by 40 μm, and the layer thickness of the heat generating composition is 400 μm. This example is the same as Example 4 except that.

As the coating material 4, a coated ball (water basis 240 g / Daishowa Paper Co., Ltd.)
m ² ) 4c, a part of the moisture of the exothermic composition is gradually absorbed by the water-absorbing layer of the packaging material, and the barrier layer is lost. As a result, the exothermic reaction proceeds rapidly by contact with air.

When the coating material 4 is a single layer of paper,
It is preferable to perform a water-resistant treatment or a water-repellent treatment from the viewpoint of preventing seepage.

When the water absorbing capacity of the water absorbing layer of the packaging material is lower than the free water absorbing capacity of the heat generating composition, the free water causes bleeding.

In the case of shoes, free water is easily separated and bleeding is likely to occur due to pressurization by weight, so it is important that the packaging material has a sufficient amount of water absorption.

The coating material becomes one layer of recycled paper, which is advantageous in terms of effective use of resources and significant cost reduction.

The thickness of the heat-generating composition layer was reduced to 400 μm to increase the water absorption ratio of the water-absorbing layer with respect to the moisture in the heat-generating composition, to prevent oozing, to greatly accelerate the initial heat generation, and to increase the heat-generating composition. After consumption of water in the object, it absorbs the moisture in the shoe and maintains a mild heat generation. Since the inside of the shoe dries due to moisture absorption, the effect of feeling relatively warm even at low temperatures is maintained.
Further, the thickness of the heat-generating composition is as thin as about 1 mm and the feeling of discomfort is further reduced, and shoes of the same size as conventionally used shoes can be used, so there is no need to dare to increase the size of the shoes. .

A paste-like heat-generating composition 2 similar to that used in Example 4 was formed on a substrate 3 having a width of 180 mm by rotary screen printing of a plate having a thickness of 400 μm, except for the width of the outer peripheral portion of 8 mm. Is printed, and a styrene-isoprene-styrene block copolymer-based hot melt adhesive is applied over the entire surface at a basis weight of 9 g / m ² immediately after spray coating, and the seal is pressed and bonded. In order to make the seal width L around each heating element 8 mm, one after another, die-cut thickness 1.5 by rotary die cutting.
An ultra-thin mm heating element for shoes was manufactured. The moisture permeability of the coating material 4 is about 4,000 g / m ² · 24 h by the Lissi method.
What was r was used.

By the way, the base material 3 and the coating material 4 were bonded to each other with a hot melt adhesive by spraying. Absorption rate of moisture of this paste-like exothermic composition 2 to the packaging material (K weight%)
Was about 3% by weight as measured by the method described above.

[0181]

As described above, the packaging material for a heating element according to the present invention is a flat packaging material that contains a heat-generating composition that contains water and whose heat generation rate is suppressed by free water. The flat packaging material has at least a portion having air permeability, and is composed of a film-shaped or sheet-shaped base material and a film-shaped or sheet-shaped coating material. One has water absorption,
The water-absorbing amount of the water-absorbing substrate or coating material is 1 g / m
More than ^two .

The heating element packaging material according to the present invention is a flat packaging material that contains a water-containing heat-generating composition in which the rate of heat generation is suppressed by free water. While eliminating the adverse effects in the manufacturing process by using, the exothermic composition is used in such a manner that the water absorption is 1 g / m ^2.
Transferred and encapsulated in a packaging material comprising the above-described base material and / or coating material, a part of the moisture of the heat-generating composition is gradually transferred to and absorbed by the packaging material after the heating element is manufactured and before shipping. As a result of the loss of the barrier layer, it is possible to shorten the heating start time of the heating element at the time of use, to obtain remarkably excellent heat generation characteristics, and to efficiently produce a heating element with extremely stable quality. .

The heating element according to the present invention contains water, and the heat-generating composition of which the heat generation rate is suppressed by free water is encapsulated in a flat packaging material. A heating element wrapping material is used, the heating element wrapping material is encapsulated with the heat-generating composition, and a base material and a coating material are joined at an outer peripheral portion of the heat-generating composition. While the use of the composition eliminates the adverse effects of the production process, the exothermic composition is transferred and encapsulated in a packaging material comprising a base material and / or a coating material having a water absorption of 1 g / m ² or more. Moisture in the composition gradually migrates and absorbs into the packaging material between the water-absorbing layer of the packaging material and the exothermic composition until an equilibrium state is reached, causing the barrier layer to be lost and causing an exothermic reaction of the heating element during use. Progresses rapidly, and extremely excellent heat generation characteristics are obtained. The quality is extremely to stability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a heating element according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a heating element according to a third embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a heating element according to a fifth embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing another embodiment of the base material suitably used in the present invention.

FIG. 5 is a schematic sectional view showing another embodiment of a coating material suitably used in the present invention.

[Explanation of symbols]

Reference Signs List 1 packaging material 2 paste-like heat-generating composition 3 base material 3a heat-sealing layer (hydrophobic and heat-sealing nonwoven fabric) 3b water-absorbing layer (hydrophilic / water-absorbing nonwoven fabric) 3c non-breathable layer (non-breathable polyethylene film) 3d Reinforcing layer (reinforcing nonwoven fabric) 4 Coating material 4a Reinforcing layer (reinforcing nonwoven fabric) 4b Air permeability control layer (polyethylene porous film, paper) 4c Water absorbing layer (hydrophilic / water absorbing nonwoven fabric, paper) 4d Heat seal layer ( Hydrophobic and heat-sealing nonwoven fabric) 5 Adhesive layer 6 Release paper L Seal width

Claims (7)

[Claims] 1. A flat packaging material for enclosing a heat-generating composition containing water and having a heat generation rate suppressed by free water, wherein at least a part of the flat packaging material has air permeability. Along with the film-shaped or sheet-shaped base material and the film-shaped or sheet-shaped coating material, at least one of the base material or the coating material has water absorption, and the water-absorbing base material or the coating material A packaging material for a heating element, having a water absorption of 1 g / m ² or more. 2. The packaging material for a heating element according to claim 1, wherein a joining portion between the base material and the coating material in the flat packaging material is adhered by heat bonding, heat fusion or a hot melt adhesive. 3. A heat-generating composition according to claim 1 or 2, which contains a heat-generating composition containing water and having a heat generation rate suppressed by free water. A heating element in which a base material and a covering material are joined. 4. The heating element according to claim 3, wherein the heat-generating composition contains water and is in the form of a powder or flake in which the rate of heat generation is suppressed by free water. 5. The heating element according to claim 3, wherein the heat-generating composition contains water and is in the form of a paste in which the rate of heat generation is suppressed by free water. 6. The heating element according to claim 3, wherein 1 to 60% by weight of moisture in the heat generating composition is absorbed by the flat packaging material. 7. The flat packaging material according to claim 3, wherein a joining portion between the base material and the coating material is adhered by heat bonding, heat fusion, or a hot melt adhesive. Heating element.