JPH10199663A - Heat generating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat generating composition which gives rise to a heat generating efficiency similar to or surpassing Joule's heat of a resistance heat generating body by exceeding a conventional limit. SOLUTION: This heat generating composition includes conductive particles A and organic binder substance B, and includes a ferroelectric substance C and strontium titanate D. Desirably, the ratio of the total quantity of the ferroelectric substance C and strontium titanate D in the whole body of the composition excluding the volatile components is 5-35wt.%, and the ratio of the ferroelectric substance C to strontium titanate D is 1:0.1 to 1:3 in the weight ratio. The conductive particles A, desirably, comprise crystalline graphite particles a1, slurry graphite a2, conductive gelatinous carbon a3, metal grain a4, and conductive metal oxide a5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-generating composition which has the property of generating heat when energized and can exhibit high heat generation efficiency.

[0002]

2. Description of the Related Art A heat-generating composition having a property of generating heat upon energization can be used for various applications as a sheet heating element.

[0003] This kind of exothermic composition basically comprises conductive particles and an organic binder substance.

Japanese Patent Application Laid-Open No. 5-39442 discloses a conductive heat generating fluid in which a powdery material composed of scaly carbon particles having a major axis of 300 μm or less and a minor axis of 200 μm or less is dispersed and suspended in a binder substance. It is shown.

[0005] JP-A-6-231867 discloses a composition comprising conductive particles and a binder resin,
An exothermic composition in which at least a part of the conductive particles is composed of scale-like graphite particles and the binder resin is an active energy ray-curable resin is shown.

JP-A-6-231868 discloses heat-generating coarse particles formed by forming a layer of a heat-generating composition comprising conductive particles and a binder resin on the surface of coarse particles such as gravel. .

[0007] These publications also describe the case where barium titanate is used as one of the metal salts to be added as required.

[0008]

The inventions of the three publications cited above have been improved as compared with the conventional heat-generating paint, but the heat-generating efficiency of the heat-generating coating film with respect to the Joule heat of the resistance heating element is low. In the best case, it was only 85-95%.
This is presumably because the inventions of these publications mainly studied from the viewpoint of selection and combination of the conductive particles and the binder resin, and thus reached the upper limit of the heat generation efficiency.

[0009] However, before the demands that become more sophisticated every day,
It is desired to make a further leap in terms of heat generation efficiency. In order to break through the above-mentioned wall of heat generation efficiency, it is necessary to find a solution based on a different idea.

[0010] Under such a background, an object of the present invention is to provide a heat-generating composition which can exceed the conventional limits and provide a heat-generating efficiency equivalent to or exceeding the Joule heat of a resistance heating element. It is assumed that.

[0011]

The exothermic composition of the present invention comprises conductive particles (A) and an organic binder substance (B), and further comprises a ferroelectric substance (C) and strontium titanate (D). It is characterized by including.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

<Conductive particles (A)> The conductive particles (A) include scale-like graphite particles (a1), mud-like graphite (a2), conductive glue carbon (a3),
It is particularly preferable that it be composed of the metal particles (a4) and the conductive metal oxide (a5). This is because favorable heat generation performance can be obtained by using these in combination.

The scaly graphite particles (a1) have a major axis of 3
00 μm or less (preferably 100 μm or less, more preferably 10 to 60 μm) and a minor axis of 200 μm or less (preferably 60 μm or less, more preferably 5 to 40 μm).
μm) is preferably used.

As the mud graphite (a2), for example, the particle size is 100 μm or less, preferably 60 μm or less, particularly 5 to 3 μm.
One having a thickness of 0 μm is used.

As the conductive glue carbon (a3), conductive glue carbon is used, and Ketjen black is particularly important. The appropriate amount of conductive glue carbon (a3) is
Maximizes the conductive performance of the flake graphite particles (a1).

As the metal particles (a4), copper, nickel, chromium, cobalt, silver, iron, and the like are used, and nickel, chromium, or cobalt is highly practical in consideration of cost, resistance to oxidation, and the like. The particle size of the metal particles (a4) is
300 μm or less, preferably 100 μm or less, especially 0.2 μm
It is desirable to set it to 50 μm. Among these, it is particularly important to use flaky nickel particles and spherical chromium particles in combination. It is considered that the flake-like nickel particles greatly contribute to the improvement of the heat generation factor and the electric conductivity, and the spherical chromium particles serve as a fulcrum of the flake-like nickel particle arrangement.

As the conductive metal oxide (a5), tin,
Oxides of metals such as iron, nickel, chromium, cobalt, and copper are used, and tin oxide and nickel oxide are particularly important. The particle size of the metal oxide (a5) is desirably 300 μm or less, preferably 100 μm or less, particularly preferably 2 to 15 μm.

<Organic binder substance (B)> As the organic binder substance (B), silicone resin, polyester silicone resin, epoxy silicone resin, thermosetting acrylic resin, thermosetting polyester resin, alkyd resin, urethane Resin, epoxy resin, melamine resin, etherified melamine resin, phenol resin,
Thermosetting or active energy ray-curable organic binder materials including polyimide resin, active energy ray-curable resin; polyolefin resin, ethylene-vinyl acetate copolymer resin, chlorinated polyolefin resin, styrene resin, polyamide Resin, fluorine resin, cellulosic polymer (esterified cellulose derivative or etherified cellulose derivative), polyetheretherketone,
Thermoplastic organic binder materials such as polyvinyl alcohol-based resins; and the like are used. For the organic binder material (B), select the most suitable one or the most suitable combination, taking into account the heat resistance, which is a feature of the thermosetting organic binder material, and the low-temperature film forming property, which is a feature of the thermoplastic organic binder material. Is preferred.

<Ferroelectric substance (C)> As the ferroelectric substance (C), barium titanate, lead titanate or the like is used, and barium titanate is particularly preferable. Barium titanate is considered to be a composite oxide of barium and titanium having a titanate composition, rather than a barium titanate salt. Barium titanate is at room temperature and 120
At a temperature of less than ° C., it has a tetragonal system perovskite structure and exhibits ferroelectricity. Lead titanate also has a tetragonal bevelskite structure at room temperature and exhibits ferroelectricity at a primary transition temperature of 490 ° C or lower.

<Strontium titanate (D)> In the present invention, strontium titanate (D) is blended in addition to the above components. The feature of the present invention is that strontium titanate (D) is used together with the ferroelectric substance (C).

Strontium titanate (D) is also considered to be a double oxide of strontium and titanium having a titanate composition, but does not exhibit ferroelectricity unlike barium titanate. The crystals are ideally equiaxed with a colorless belovskite structure.

<Blending Ratio> As described above, the heat-generating composition of the present invention comprises conductive particles (A), an organic binder substance (B),
The ferroelectric substance (C) and the strontium titanate (D) are contained, and the proportion of each component is preferably selected from the following ranges.

First, the ratio of the total amount of the ferroelectric substance (C) and the strontium titanate (D) to the total composition excluding volatile components is 5 to 35% by weight (particularly 10 to 30% by weight). Preferably, the ratio between the ferroelectric substance (C) and the strontium titanate (D) is 1: 0.1 to 1: 3 (particularly 1: 0.2 to 1: 1) by weight. (C) + (D)
When the ratio is too small, the effect of improving the heat generation efficiency is small, and when it is too large, the heat generation efficiency is rather reduced.
In the ratio between (C) and (D), when the ratio of (D) is too small, the effect of improving the heat generation efficiency is small, and when it is too large, the heat generation efficiency is rather reduced.

The proportion of the conductive particles (A) in the whole composition excluding volatile components is 25 to 65% by weight (particularly 25 to 50%).
% By weight), and an insufficient amount of the conductive particles (A) leads to a shortage of heat generation performance, so that heat is not generated unless a high voltage is applied. The ratio of the organic binder substance (B) is 15 to
An appropriate amount is 45% by weight (particularly 15 to 35% by weight), and an insufficient amount of the binder resin (B) causes insufficient strength of a coating film or a molded product. Excessive conductive particles (A), organic binder substance (B)
If the amount is too large, the proportion of other components becomes relatively small, so that the balance is lacking and the desired improvement effect cannot be obtained.

When the proportion of each component is selected from the above range, a balanced and optimal result is obtained.

Focusing on the conductive particles (A), the conductive particles
The proportion of the flaky graphite particles (a1) in the (A) is 20% by weight or more and the flaky graphite particles (a) with respect to the organic binder substance (B).
It is desirable that the ratio of 1) is 15 to 85% by weight. If the ratio is out of these ranges, the desired heat generation performance may not be sufficiently obtained.

When the muddy graphite (a2), the conductive glue carbon (a3), the spherical metal particles (a4), and the conductive metal oxide (a5) are used together with the scale-like graphite particles (a1), the scale-like graphite particles are used. (a1): Conductive aggregated carbon (a3) is 99: 1 to 60:40 by weight, and scale-like graphite particles (a1): (spherical metal particles (a4) + conductive metal oxide)
The weight ratio of (a5)) is desirably 80:20 to 20:80.

<Other Compounds> In addition to the above essential components, the composition of the present invention may contain, if necessary, a halogen compound such as iron, copper, tin, sodium, nickel, chromium, or cobalt, such as tin chloride or chloride. Nickel may be contained, and an extender or a coloring pigment may be contained. Reinforcing fibers and conductive fibers may be included.

In order to ensure coating properties and storage stability,
Diluents (solvents, etc.), water, antisettling agents (polymers, bentonite, finely divided silica, etc.), dispersants (surfactants, etc.), stabilizers (antioxidants, etc.), leveling agents, foaming agents, reinforcing fibers , A drying oil, a semi-drying oil, a softening agent (such as ethylene glycol), and a salt (such as salt) can be appropriately blended.

<Formation of Planar Heating Element> The heat-generating composition is prepared by mixing the heat-generating composition with metal, plastics, wood, paper, cloth,
After being applied to an arbitrary object such as a ceramic plate or concrete, heating or irradiation with an active energy ray is performed to form a cured film. The shape of the object is not limited to a planar shape,
It may be linear, rod-shaped, cylindrical, or any other three-dimensional curved surface. After casting or casting the composition on a suitable support or mold, it is heated or irradiated with active energy rays to form a film, sheet, or other molded product (tile, brick, tile, etc.). You can also. The thickness of the cured film is 0.
It is often about 01 to 0.3 mm, but is not necessarily limited to this range.

An insulating layer made of an insulating paint or an insulating film is arranged on the coating film or the molded product thus obtained. However, if the thickness of the insulating layer is excessively large, heat transfer may be hindered. Therefore, care should be taken to keep the thickness as small as possible.

The electrodes and terminals are formed of a highly conductive material such as silver paste or metal foil.

The energization may be alternating current or direct current, and can be applied from a low voltage of about 3V to a high voltage of about 240V. For example, 100V power supply for home,
12V battery power for passenger cars, 24V for trucks
Both battery power and dry batteries can be used.

<Function> The essential components constituting the exothermic composition of the present invention are summarized as follows. Conductive particles (A) (especially scaly graphite particles (a1), muddy graphite (a2), conductive aggregated carbon (a3), metal particles (a4) and conductive metal oxides (a5)) Organic binder substance (B) ・ Ferroelectric substance (C) (especially barium titanate) ・ Strontium titanate (D)

The conductive particles (A) are components that generate heat when energized, and the organic binder material (B) is a component that forms a coating film or a molded product.

Among the conductive particles (A), scaly graphite particles (a1)
Shows excellent conductivity and heat generation performance due to its excellent conductivity and its unique particle shape. Metal particles
(a4) complements the exothermic performance of the scaly graphite particles (a1),
Contributes to more stable heat generation. Mud graphite (a2) and conductive aggregated carbon (a3) can be mixed in appropriate amounts to improve the conductivity of squamous graphite particles (a1) and maximize heat generation performance, This is effective in adjusting the resistance value and developing a high temperature at a low voltage. The presence of the conductive metal oxide (a5) is advantageous for improving the heat generation efficiency. This is because the conductivity of a conductive metal oxide is almost the same as that of a metal, but when the temperature rises due to energization, in the case of a metal, the resistance decreases and the current increases, so that the power consumption increases. On the other hand, in the case of the conductive metal oxide, the same tendency is exhibited, but the current does not increase as much as in the case of the metal, and this is advantageous in terms of heat generation efficiency.

When a ferroelectric substance (C) (particularly barium titanate) is applied with an electric field, the electric charge moves microscopically for a short distance to be polarized, and as a result, electromagnetic induction energy is generated. It is thought to be. In a system in which strontium titanate (D) which does not exhibit ferroelectricity coexists and the conductive particles (A) coexist, electron transfer is considered to be appropriate for the exothermic effect. In any case, ferroelectric substance (C) and strontium titanate (D)
By coexisting with the above, compared to the system of the conductive particles (A) or the system composed of the conductive particles (A) and the ferroelectric substance (C), conventionally, it is considered as a wall in terms of heat generation efficiency. This breaks the limit, and makes it possible to obtain a heating efficiency equal to or exceeding the Joule heat of the resistance heating element.

[0039]

The present invention will be further described with reference to the following examples. Hereinafter, "parts" refers to parts by weight.

Example 1 <Preparation of Exothermic Paint> As the conductive particles (A), 100 parts of a powder mixture obtained by uniformly mixing the following particles were prepared. 27.8 parts of scale-like graphite particles (major axis: 30 to 40 μm, minor axis: 1)
0-20 μm) ・ 44.4 parts of mud-like graphite particles (particle size: 5-15 μm) ・ 3.7 parts of spherical Ketjen black particles (particle size: 5-1)
5μm) ・ 11.1 parts of flake-like nickel particles (particle size 0.5-5.0μ)
m) ・ 7.4 parts of spherical chromium particles (particle size 0.5-5.0 μm) ・ 5.6 parts of conductive tin oxide (particle size 2-5 μm)

As the organic binder material (B), 103.7 parts of a solution having the following composition was prepared.・ 14.8 parts of pure silicone resin ・ 7.4 parts of silicone polyester ・ 7.4 parts of epoxidized silicone ・ 26.7 parts of butylated melamine resin ・ 47.4 parts of solvent

The powder mixture 100 of the above-mentioned conductive particles (A)
In the mixture, 44.4 parts of barium titanate (particle size: 10 to 15 μm) as an example of the ferroelectric substance (C) and 11.2 parts of strontium titanate (D) were mixed. Solution 103.7 parts, extender pigment 14.8 parts (7.4 parts titanium oxide and aluminum oxide
7.4 parts), 11.1 parts of methyltrimethoxysilane as an anti-settling agent, flowability improver (3 parts by weight ratio of long-chain polyaminoamide phosphate to long-chain polyaminoamide ester salt:
1 part) 7.5 parts, fat and oil processing agent as coating film softener (7.4 parts of thermally polymerized linseed oil and 3.7 parts of cashew nut shell product) 11.1 parts, solvent as spreader and viscosity modifier (37.0 parts of xylene and methyl) Isobutyl ketone 22.2
59.2 parts) and stirred and mixed with a stirrer at a rotation speed of 100 to 240 rpm to prepare a heat-generating paint having strong thixotropic properties.

<Preparation of Sheet Heating Element>
An 8mm wide copper tape as an electrode was attached to both long sides
56mm (including 16mm part on both copper tapes) x 125 of SUS304 board coated with insulating paint of dimensions 0mm x 155mm
mm area, brushed, dried at room temperature,
Curing was performed for 1 hour at 180 ° C. for 1 hour to produce a heating plate. The thickness of the heat-generating coating film was 0.20 mm. The volume resistivity of the dried coating film was 2.05 Ω · cm (25 ° C.).

This heating plate is sandwiched by a stainless steel plate (SUS304) having an insulating layer formed by applying an insulating paint so that it may be immersed in water, and tightened with bolts and nuts to form a sheet heating element. Produced. The periphery was sealed with silicone rubber, and a lead wire was taken out from the end of the copper tape.

<Heat generation test> A baking-painted steel pail (1360 g in weight) was wrapped with glass wool, covered with a plate made of expanded polystyrene, and a glass beaker (92 g in weight) was placed inside. The above planar heating element (weight: 216 g with two stainless steel plates) was placed on top, and further filled with 10 kg of pure water.

A temperature sensor was attached and set on the surface of the planar heating element and the outside of the pail, and pure water was stirred with a stirrer (100 rp).
m) While passing through the transformer, electricity was passed through the sheet heating element for 60 minutes, and the temperature change at each part of the temperature sensor was measured to determine the heat generation efficiency of the heat-generating coating film. Table 1 below shows the temperature change of each part and the supplied electrical data which are the basis of the calculation.

[0047]

[Table 1] Energizing time Water temperature Heating element surface Pail outside Current voltage Power (min) (° C) Temperature (° C) Temperature (° C) (A) (V) (W) 0 27 27 27 1.84 58.0 106.72 5 27 35 27 1.88 58.2 109.42 10 29 48 28 1.89 58.5 110.57 15 30 55 28 1.89 58.2 110.00 20 31 73 28 1.91 58.6 111.93 25 32 96 29 1.90 58.5 111.15 30 33 105 29 1.90 58.4 110.96 35 34 110 30 1.88 57.7 108.48 40 35 113 30 1.90 58.3 110.77 45 35 115 31 1.90 58.2 110.58 50 36 116 32 1.90 58.2 110.58 55 36 117 33 1.92 58.8 112.90 60 37 118 33 1.93 58.9 113.68 Average---1.90 58.3 110.60 (Power supply voltage 60.0 volts applied)

<The amount of heat generated by the heat-generating coating film> The amount of heat given to water is 10,000 × (37−27) × 1.00 = 100000.0 cal, and the amount of heat given to the sheet heating element is 216 × (118−27) × 0.12 = 2358.7
cal, the amount of heat given to the pail can is 1360 x (33-27) x 0.12
= 979.2 cal, the total calorie is 103337.9 cal, ie 1
It is 03.3 kcal. However, the specific heat of the pail was set to 0.12.
Although the specific heat seems to depend on the temperature, it was calculated as a constant.

<Heat generation efficiency by heat-generating coating film> The heat generation efficiency of the calorific value obtained by the test on the heat-generating coating film with respect to Joule heat is calculated as follows. The exothermic efficiency of the exothermic coating film of this example was 108.6%, which is very good.・ Joule heat: 860kcal heat generation at 1000W power ・ The amount of heat generated by the heat generating coating film according to the present invention: 1 at 110.60W power
03.3kcal heat generation ・ Heat generation efficiency: 1000 × 103.3 / 110.60 = 934.0 100 × 934.
0/860 = 108.6%

Example 2 <Preparation of Exothermic Paint> According to Example 1, an exothermic paint having the following composition was prepared.・ 27.5 parts of scale-like graphite particles (major axis: 30-40 μm, minor axis: 1)
0-20 μm) ・ 43.9 parts of muddy graphite particles (particle size: 5-15 μm) ・ 3.1 parts of spherical Ketjen black particles (particle size: 5-1)
5μm) ・ 11.8 parts of flake-like nickel particles (particle size 0.5 ~ 5.0μ)
m) ・ 7.8 parts of spherical chromium particles (particle size 0.5-5.0 μm) ・ 5.9 parts of conductive tin oxide (particle size 2-5 μm) ・ 67.6 parts of organic binder material (B) (pure silicone resin)
A varnish consisting of 8.8 parts, silicone polyester 7.0 parts, epoxidized silicone 4.0 parts, butylated melamine resin 12.0 parts, organic solvent 14.7 parts, ethylene-vinyl acetate copolymer 8.0 parts, chlorinated paraffin 0.6 parts, xylene 8.0
Varnish consisting of 4.5 parts of isophorone) ・ 14.6 parts of barium titanate (particle size: 10 to 15 μm) ・ 7.9 parts of strontium titanate ・ 15.6 parts of extender (7.8 parts of titanium oxide and 7.8 parts of aluminum oxide) ・ 39.2 parts Additives (methyltrimethoxysilane 11.8
Part, polymerized linseed oil 7.8 parts, cashew nut shell liquid processed product 3.9 parts, long-chain polyaminoamide phosphate 5.9 parts, long-chain polyaminoamide ester salt 2.0 parts, aminated hectorite organic clay 7.8 parts) ・ 62.7 parts of organic solvent (39.2 parts of xylene and 23.5 parts of methyl isobutyl ketone)

<Preparation of Sheet Heating Element and Heating Test> A sheet heating element similar to that of Example 1 was prepared using this heat-generating paint. The thickness of the exothermic coating film was 0.12 mm. The volume resistivity of the dried coating film was 1.25 Ω · cm (25 ° C.). Using this planar heating element, data for obtaining heat generation efficiency was obtained in the same manner as in Example 1. Table 2 shows the results.

[0052]

[Table 2] Energizing time Water temperature Heating element surface Pail outside Current voltage Power (min) (° C) Temperature (° C) Temperature (° C) (A) (V) (W) 0 25 25 25 1.75 57.5 103.63 5 25 33 25 1.79 58.2 104.18 10 26 43 25 1.83 58.2 106.51 15 26 55 25 1.83 58.3 106.69 20 27 70 25 1.85 58.2 107.67 25 28 84 26 1.85 58.4 108.04 30 28 98 26 1.88 58.5 109.98 35 29 110 26 1.91 58.5 111.74 40 30 116 27 1.92 58.5 112.32 45 31 120 27 1.90 58.2 110.58 50 33 122 28 1.90 58.2 110.58 55 35 123 29 1.93 58.7 113.29 60 36 124 30 1.95 58.9 114.86 Average---1.87 58.3 109.24 (Power supply voltage 60.0 volts applied)

<The amount of heat generated by the heat-generating coating film> The amount of heat given to water was 10,000 × (36−25) × 1.00 = 110000.0 cal, and the amount of heat given to the sheet heating element was 205 × (124−25) × 0.12 = 2435.4
cal, the amount of heat given to the pail is 1360 x (30-25) x 0.12
= 816.0 cal, the total calorific value is 113251.4 cal, that is, 11
It is 3.25 kcal.

<Heat generation efficiency by heat-generating coating film> The heat generation efficiency of the heat value obtained by the test on the heat-generating coating film with respect to Joule heat is calculated as follows. The exothermic efficiency of the exothermic coating film of this example was 120.5%, which is very good.・ Joule heat: 860kcal heat generation at 1000W power ・ The calorific value of the heat generating coating film according to the present invention: 1 at 109.24W power
13.25kcal heat generation ・ Heat generation efficiency: 1000 × 113.25 / 109.24 = 1036.7 100 × 10
36.7 / 860 = 120.5%

Example 3 <Preparation of Exothermic Paint> According to Example 1, an exothermic paint having the following composition and a strong thixotropic property was prepared. An exothermic paint was prepared.・ 11.8 parts of scale-like graphite particles (major axis: 30-40 μm, minor axis: 1)
0-20 μm) ・ 17.6 parts of muddy graphite particles (particle size: 5-15 μm) ・ 2.9 parts of spherical Ketjen black particles (particle size: 5-1)
5μm) 8.2 parts of flake nickel particles (particle size 0.5 ~ 5.0μ)
m) ・ 2.9 parts of spherical chromium particles (particle size 0.5-5.0 μm) ・ 5.9 parts of conductive tin oxide (particle size 2-5 μm) ・ 129.5 parts of organic binder substance (B) (50% silicone polyester resin varnish) 11.8 parts, 11.8 parts of 60% butylated melamine resin varnish, 29.5 parts of general-purpose resin varnish consisting of 5.9 parts of 53% acrylic resin varnish, 23.5 parts of ethylene-vinyl acetate copolymer, 3.8 parts of chlorinated paraffin, xylene 58.9
Parts, synthetic resin varnish consisting of 13.8 parts of isophorone 100 parts) ・ 15.0 parts of barium titanate (particle size: 10 to 15 μm) ・ 15.0 parts of strontium titanate ・ 17.6 parts of extender (8.8 parts of titanium oxide, hydrous aluminum silicate) 5.9 parts and hydrous magnesium silicate 2.9
Parts) ・ 20.6 parts of additives (methyltrimethoxysilane 8.8
Part, polymerized linseed oil 5.9 parts, cashew nut shell liquid processed product 3.9 parts, long-chain polyaminoamide phosphate 4.4 parts, long-chain polyaminoamide ester salt 1.5 parts) 52.9 parts of organic solvent (xylene 38.2 parts and methyl isobutyl ketone 14.7) Part)

<Preparation of Sheet Heating Element and Heating Test> A sheet heating element similar to that of Example 1 was prepared using this heat-generating paint. The thickness of the heat-generating coating film was 0.15 mm. The volume resistivity of the dried coating film was 1.70 Ω · cm (25 ° C.). Using this planar heating element, data for obtaining heat generation efficiency was obtained in the same manner as in Example 1. Table 3 shows the results.

[0057]

[Table 3] Energizing time Water temperature Heating element surface Pail outside Current voltage Power (min) (° C) Temperature (° C) Temperature (° C) (A) (V) (W) 0 25 25 25 1.59 58.9 93.65 5 25 42 25 1.71 58.3 99.69 10 26 63 25 1.75 58.4 102.20 15 27 82 25 1.77 58.2 103.01 20 28 97 25 1.75 58.2 101.85 25 29 105 26 1.75 58.0 101.50 30 30 108 26 1.74 58.4 101.62 35 31 111 26 1.74 58.3 101.62 40 32 113 27 1.78 58.7 104.49 45 33 115 27 1.81 58.8 106.43 50 33 115 28 1.83 58.5 107.06 55 34 115 28 1.83 58.5 107.06 60 34 116 29 1.85 59.4 109.89 Average---1.76 58.5 103.08 ( Apply power supply voltage of 60.0 volts)

<The amount of heat generated by the heat-generating coating film> The amount of heat applied to water is 10,000 × (34−25) × 1.00 = 90000.0 cal, and the amount of heat applied to the heat generating substrate is 198 × (116−25) × 0.12 = 2162.2 cal
The amount of heat given to the pail is 1360 x (29-25) x 0.12 = 6
52.8 cal, the total calorie is 92815.0 cal, that is, 92.815 k
cal.

<Heat Efficiency by Heating Coating Film> The heat generation efficiency of the heating value obtained by the test on the heat generating coating film with respect to Joule heat is calculated as follows. The exothermic efficiency of the exothermic coating film of this example is 104.7%, which is extremely excellent.・ Joule heat: 860kcal heat generation at 1000W power ・ The calorific value of the heat generating coating film according to the present invention: 9 at 103.08W power
2.815kcal heat generation ・ Heat generation efficiency: 1000 × 92.815 / 103.08 = 900.4 100 × 90
0.4 / 860 = 104.7%

<The exothermic temperature of the exothermic coating film of Examples 1 to 3> From the relationship between the watt density calculated from the volume resistivity of the exothermic coating film and the exothermic temperature, the exothermic temperature in Examples 1 to 3 was as follows. Become like The calculation formula is as follows. W = (1 / δ) × (S × V ² / L) where W is watt, δ is volume resistivity, S is length of electrode × film thickness, V is volt, and L is distance between electrodes. . In the case of Example 1 W = (1 / 2.05) × (12.5 × 0.02 × 60 × 60) /4=109.756 Watt density = 109.756 / 50 = 2.20 W / cm ^{2 From} FIG. It reaches 480 ° C. -In the case of Example 2 W = (1 / 1.25) x (12.5 x 0.012 x 60 x 60) / 4 = 108.0 Watt density = 108.0 / 50 = 2.16 W / cm ^{2 From} Figs. 470 ° C. In the case of Example 3 W = (1 / 1.70) × (12.5 × 0.015 × 60 × 60) /4=99.265 Watt density = 99.265 / 50 = 2.00 W / cm ^{2 From} FIGS. 425 ° C.

In the heat generation test at the heat generation temperature as described above, when the temperature exceeds 400 ° C., the copper tape used as the electrode material may be burned out. Therefore, as described above, the test was performed by immersing the sheet heating element in water. FIG. 3 shows the results of plotting the exothermic temperatures of the planar heating elements in water in Examples 1 to 3 based on Tables 1 to 3.

[0062]

The use of the exothermic composition of the present invention breaks the limit of heat generation efficiency, which was conventionally considered to be a wall, and is equivalent to or exceeds the Joule heat of the resistance heating element. Is obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a watt density and a heat generation temperature.

FIG. 2 is a graph showing a relationship between watt density and heat generation temperature.

FIG. 3 is a graph showing the results of plotting the exothermic temperatures of the planar heating elements in water in Examples 1 to 3 based on Tables 1 to 3.

Claims (3)

[Claims] 1. An electroconductive particle (A) and an organic binder substance
A heat-generating composition comprising (B) and further comprising a ferroelectric substance (C) and strontium titanate (D). 2. The composition according to claim 1, wherein the proportion of the total amount of the ferroelectric substance (C) and strontium titanate (D) in the total composition excluding volatile components is 5 to 35% by weight, and the ferroelectric substance (C )
And strontium titanate (D) in a weight ratio of 1:
The exothermic composition according to claim 1, wherein the ratio is 0.1 to 1: 3. 3. The conductive particles (A) are composed of scale-like graphite particles (a1), mud-like graphite (a2), conductive aggregated carbon (a3), metal particles (a4) and conductive metal oxides (a5). The exothermic composition according to claim 1, comprising: