JP2003022888A - Surface heater and heating method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface heater and its heating method, capable of obtaining superior high-speed heating performance, without using a power supply using a complicated control circuit. SOLUTION: A first pair of electrodes 21 and a second pair of electrodes 22 are formed on the obverse, the reverse, or both obverse and reverse of an electric-heating layer 10 so as not to be horizontally overlapped. Each pair of electrodes is connected to a power supply, through a separate switch that can be independently opened and closed. An additional electric-heating layer may be laminated on the surface of the electric-heating layer where the pairs of electrodes are formed, or a base material layer may be laminated on the outermost obverse and the outermost reverse. In its heating method, both pairs of electrodes are energized first to heat the surface heater, a shorter temperature balancing time is measured, when only either one of the pairs of electrodes is energized, and current supply to one pair of electrodes is stopped at a time point before the shorter time to bring temperature balancing conditions to the surface heater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface heating element suitable as a heat source for generating heat with a flat and uniform temperature distribution.
In particular, the present invention relates to a surface heating element having a short heating time and an excellent rapid heating property and a heating method thereof.

[0002]

2. Description of the Related Art Surface heating elements are used for floor heating, electric carpets,
It is widely used as a heat source for consumer applications such as snow melting heaters and industrial applications such as heat insulation of pipes and tanks. Examples of the conventional surface heating element include (1) a sheet obtained by kneading conductive powder in a thermoplastic resin, and (2)
It is known that a conductive powder is mixed with a silicone resin or an organic vehicle to form a paste, and the paste is formed on a substrate by using a thick film printing technique.

For example, as the form of the above (1), as disclosed in Japanese Patent Publication No. 54-13625, a thermoplastic resin such as polyethylene, a conductive carbon such as graphite or carbon black is used. The conductive powder is formed by blending and kneading, and is molded into a sheet. The conductive powder is mixed in the resin, and the physical contact between the conductive powder provides electrical continuity. Further, in such a surface heating element, the resin has an extremely large coefficient of thermal expansion between the conductive powder and the thermoplastic resin, and the resin exhibits a larger coefficient of expansion at a temperature equal to or higher than the glass transition point. The spacing between the particles of the blended conductive powder expands as the temperature rises, and at the glass transition point or higher, the spread becomes extremely large, exhibiting a positive temperature characteristic (PTC characteristic) of electrical resistance. Therefore, it becomes difficult for an electric current to flow in the heating element before and after that temperature, and the self-temperature control is possible.

On the other hand, as the form of the above (2),
For example, there is one disclosed in Japanese Examined Patent Publication (Kokoku) No. 58-15913, the details of which are described in Silicone Resin Varnish,
There is described a surface heating element produced by mixing graphite powder, an organic solvent, a fluidity adjusting agent and the like, coating the mixture on a substrate, and then firing the mixture at a temperature of 250 to 450 ° C.

[0005]

However, in the case of the above-mentioned form (1), since the positive temperature characteristic of the electric resistance (volume resistivity), a large voltage is applied at room temperature to generate a large amount of heat (unit: Even if the time (per unit area) is increased, when the temperature reaches a high temperature, the electric resistance rapidly increases, the current value decreases, the calorific value decreases, and the temperature does not rise excessively. Therefore, it is possible to raise the temperature all at once to a temperature at which the resistance value changes greatly. However, since the thermoplastic resin is the main component, a high-temperature surface heating element has a drawback. Also, during repeated thermal expansion of the resin, the contact state and arrangement state of the carbon particles in the resin matrix may change, the control temperature may change, or the temperature may rise above the control temperature for further control. There was a problem that the property was remarkably deteriorated and a fire occurred. Further, in order to improve such problems, improvements such as crosslinking of resins have been proposed. However, there remain problems that the material is special, the cost is high, and the labor of processing is increased.

On the other hand, in the case of the form (2), since the heating element itself does not have the self-temperature controllability, the above-mentioned problems derived from the self-temperature controllability can be avoided, but the ultimate temperature is Since the area, resistance value, and applied voltage are determined, the rate of temperature rise cannot be controlled, and the rapid heating property is poor. Of course, it is also possible to perform feedback temperature control in which the temperature is measured with a temperature sensor such as a thermocouple and the power supplied to the surface heating element is controlled by a thyristor or the like based on the measured value. However, for that purpose, it becomes necessary to add a control circuit to the power supply.

That is, an object of the present invention is to provide a surface heating element which has a short heating time and an excellent rapid heating property without using a power source using a complicated control circuit or a special electric heating material. is there. It is also to provide such a heat generation method.

[0008]

[Means for Solving the Problems] In order to solve the above problems,
In the surface heating element of the present invention, in the surface heating element using the electric heating layer that generates heat by Joule heat, the first electrode pair and the second electrode pair are arranged such that they do not overlap with each other in the plane direction,
The heating layer is formed only on the front surface, only on the back surface, or on both the front surface and the back surface, and the first electrode pair and the second electrode pair are connected to the power source through separate switches that can be independently opened and closed. Alternatively, the surface heating element of the present invention has a structure in which an electric heating layer is further laminated on the surface of the electric heating layer on which the electrode pair is formed.

With such a structure, the surface heating element can quickly reach the desired equilibrium temperature in a short period of time when the temperature rises early in the heat generation. Therefore, when it is used for a heating device or the like, a quick heating effect is obtained, and the temperature rising time is short and the rapid heating property is excellent. In addition, it is not necessary to use a special electrothermal material such as a material having PTC characteristics, and by using an ordinary resistor, stable heat generation characteristics can be obtained without deterioration over time due to the effect of repeated thermal expansion of the resin. it can. Further, even if the temperature control circuit is not specially attached to the power source, a constant temperature can be maintained if only the current value is kept constant.

In addition, the surface heating element of the present invention further has a base material layer of an insulating material laminated on any one or both of the outermost surface or the backside of the electrothermal layer in any of the above constitutions. It is made up of

With such a constitution, the electrothermal layer can be supported by the base material layer, the mechanical strength of the surface heating element can be reinforced and the insulating property can be imparted.

In the heating method of the present invention, using either of the above surface heating elements, first, both the first electrode pair and the second electrode pair are energized to generate heat, and then the heating layer is applied to both electrodes. In the temperature equilibration time when only one of the pair is energized, at a time point earlier than the shorter time, the energization to either one of the two electrode pairs is stopped and the surface heating element is allowed to reach temperature equilibrium. I decided to get it.

By adopting such a method, it is possible to accelerate the rise of the temperature in the initial stage of heat generation and reach the desired equilibrium temperature in a short time. Therefore, when it is used for a heating device or the like, a quick heating effect can be obtained, and thus the temperature rising time can be shortened and a rapid heating property can be realized. Further, even if the temperature control circuit is not specially attached to the power source, a constant temperature can be maintained if only the current value is kept constant.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

[Outline] First, FIG. 1 is a view illustrating one form of a surface heating element of the present invention, and FIG. 1 (A) is a sectional view.
FIG. 1B is a plan view illustrating an example of a plan view pattern of a surface heating element having an arrangement of electrode pairs as shown in FIG. Note that the cross-sectional view of FIG. 1A is taken along line A- in FIG.
It is sectional drawing in the A line direction.

The surface heating element 100 shown in FIG.
Above, the first electrode pair 21 and the second electrode pair 22 are formed only on the back surface side of the electrothermal layer 10 so as not to overlap each other in the plane direction, and the first electrode pair 21 is formed. The second electrode pair 22 and the second electrode pair 22 are connected to a power source and can be energized through separate switches that can be independently opened and closed. Further, in the case of the surface heating element 100 illustrated in FIG. 1, the base material layer 30 is further disposed on the back surface side of the electric heating layer 10 such that the electrode pairs 21 and 22 are sandwiched between the base material layer 30 and the electric heating layer 10. It is a laminated structure. The surface heating element 100 having such a configuration is
For example, it can be obtained by first forming both electrode pairs 21 and 22 on the base material layer 30 by printing or the like, and then further forming the electrothermal layer 10 on it by printing or the like.

The surface heating element 100 as shown in FIG.
For example, as illustrated in FIG. 5, the first electrode pair 21 and the second electrode pair 22 are wired and heated so that they can be independently energized. That is, in the case of the same drawing, the power supply cable 310 connected to the power supply 410 via the switch 210 is connected to the first electrode pair 21. A power cable 320 connected to a power source 420 via a switch 220 is connected to the second electrode pair 22. By wiring in this way, first, the electrode layers 21 and 22 are energized to the electrothermal layer 10, and thereafter, energization to either one of the electrode pairs is stopped,
If only the remaining one electrode pair side is energized, a heating method excellent in rapid heating property can be realized.

[Various Examples of Layered Structure] Next, FIG. 2 shows another embodiment of the surface heating element of the present invention. 2A is a cross-sectional view and FIG. 2B is a plan view thereof. In addition,
The sectional view of FIG. 2A is a sectional view taken along the line AA in FIG. 2B (however, only the left half is shown).

The surface heating element 100 shown in FIG.
The plan view patterns 1 and 22 are an example of a shape different from the form of FIG. The base material layer 30, the electrode pairs 21 and 2
2. The stacking relationship of the electrothermal layer 10 is the same as that in the case of FIG.

Next, FIG. 3 is a cross-sectional view showing some examples of the layer constitution of the surface heating element of the present invention. Figure 3
In the surface heating element 100 illustrated in (A), the electric heating layer 10b is further formed on the surface of the electric heating layer 10a on which the electrode pairs 21 and 22 are formed.
It is configured by stacking.

Further, in the surface heating element 100 of FIG. 3B, the electrode pair 21 is formed on the back surface (downward in the drawing) of the electrothermal layer 10a, and the other electrode pair 22 is formed on the surface of the electrothermal layer 10a. Further, the electrothermal layer 10b has a smaller area than the electrothermal layer 10a and the electrothermal layer 10b is laminated inside the electrode pair 21 on a part of the surface of the electrothermal layer 10a on which the electrode pair 22 is formed.

Further, in the surface heating element 100 of FIG. 3C, the first electrode pair 21 is formed on the back surface (lower side of the drawing) of the electric heating layer 10a, and the second electrode is formed on the front surface (side) of the electric heating layer 10a. Electrode pair 2
2 is formed on the surface on which the second electrode pair 22 is formed,
Further, the electric heating layer 10a having a smaller area than the electric heating layer 10a is laminated and the first electrode pair 21 is formed.
The base material layer 30 is laminated on the back surface (the outermost surface of both electrothermal layers).

Further, the surface heating element 100 of FIG. 3D has a structure in which two base material layers 30a and 30b are provided, and the electric heating layer 10a is provided on the base material layer 30a via the first electrode pair 21. Is laminated, the electric heating layer 10b is further laminated on the electric heating layer 10a via the second electrode pair 22, and the base material layer 30b is further laminated on the electric heating layer 10b. Base material layer 30
a is formed on the backmost surfaces of both electrothermal layers 10a and 10b,
One of the base material layers 30b is also a structure formed on the outermost surfaces of the electrothermal layers 10a and 10b.

In the surface heating element of the present invention, the electric heating layer may be one layer as illustrated in FIGS. 1 and 2, but the above-mentioned FIG.
As illustrated in (D), an electric heating layer may be further stacked on the surface of the electric heating layer on which the electrode pair is formed to form a multilayer structure such as a two-layer structure. In these cases, the second electrothermal layer 10b is laminated on the electrode pair formation surface of the first electrothermal layer 10a so as to cover the entire electrode pair. The material, thickness, and the like of the second electric heating layer 10b may be the same as those of the first electric heating layer (however, they do not have to have the same thickness).

Further, in the surface heating element of the present invention, FIG.
As described above, the base material layer may be a multilayer, such as a configuration in which the electrothermal layer is sandwiched between the base material layers 30a and 30b. Of course, these base material layers are not essential, but when the shape cannot be maintained from the viewpoint of mechanical strength only by the electric heating layer, or when it is desired to insulate the front and back surfaces of the electric heating layer, the base material layer is formed like these. A laminated structure is preferable.

[Electrical Heat Layer] The electric heat layer 10 (or 10a, 1
As 0b), for example, conductive powder can be formed by silk screen printing a conductive ink dispersed in a resin binder.

As the conductive powder, for example, conductive carbon (graphite or the like), conductive particles of metal or metal oxide such as silver, copper, nickel, ITO or scale-like foil pieces are used. Further, as the binder resin, for example, ethylene-vinyl acetate copolymer, acrylic resin, silicone resin, polyimide resin, polyester resin, polyamide resin, etc. are used. The conductive powder is usually added in an amount of about 100 to 3000 parts by mass with respect to 100 parts by mass of the resin binder. And the thickness of the electrothermal layer is usually 5 to 100.
The thickness is about 0 μm.

The method for forming the electrothermal layer is not particularly limited. For example, in addition to the above-mentioned silk screen printing, a printing method such as gravure printing, flexographic printing, offset printing, roll transfer printing, etc. is used to form the base material layer. It can be formed in a desired pattern on top. Alternatively, a resin composition obtained by kneading a conductive powder in a resin binder can be formed into a sheet by a calender method, a melt extrusion method, a casting method, or the like. In this case, the base layer may be omitted, but this sheet may be laminated with the base layer later.

A specific example of the sheet-like electrothermal layer itself is a conductive rubber sheet in which conductive powder is added to rubber. In the case of the conductive rubber sheet, the base material layer can be omitted, and it can be easily applied to applications where the surface heating element is required to have elongation and flexibility (for example, seats and beds).

As the rubber, for example, one having high heat resistance such as silicone rubber or fluororubber is preferable. Further, EPDM (ethylene propylene diene rubber), NBR (nitrile butadiene rubber), CR (chloroprene rubber), CE (chlorinated polyethylene rubber), S
BR (styrene-butadiene rubber or the like can also be used. In the conductive rubber sheet, if necessary,
Various plasticizers such as phosphate ester plasticizers (trimethyl phosphate, tributyl phosphate, etc.) and alkylene oxide plasticizers, various extender pigments such as silicates, calcium carbonate, magnesium carbonate, magnesium silicate, clay, or the like, or It is also possible to improve heat resistance by using flame retardants, non-combustible agents, various stabilizers, and the like.

[Electrode Pair] The first electrode pair 21 and the second electrode pair 22 are formed so as not to overlap each other in the plane direction. This is because an electric current is caused to flow in the plane direction of the electric heating layer to heat the electric heating layer in a plane. The formation surface of the electrothermal layer may be only the front surface of the electrothermal layer, only the back surface, or both the front surface and the back surface. And the first electrode pair and the second
The electrode pair is connected to a power source through a separate switch that can be opened and closed independently to generate heat in the electrothermal layer. Then, with each such electrode pair, the electrothermal layer is heated by both electrode pairs,
Three types of heating, heating by the electrode pair and heating by the second electrode pair, are possible, and by switching these as will be described later, a heating method excellent in rapid heating property becomes possible.

The specific pattern shape of each electrode pair as described above is, for example, FIG. 1 (B) and FIG. 2 (B).
The shape is as illustrated in the plan view of FIG. Of course, the pattern shape of each electrode pair is not limited to the pattern shape illustrated here, and other pattern shapes are also possible.

By the way, in the case of the electrode pair in the surface heating element 100 illustrated in FIGS. 1A and 1B, the heating layer 10 is used.
In the portion, the first electrode pair 21 is composed of one linear electrode 21a existing in the central portion and two linear electrodes 21b arranged in parallel so as to sandwich both sides of the electrode 21a. Here is an example. In addition, the second electrode pair 22 includes the electrothermal layer 10
In the part, the linear electrodes 22a and 2 are arranged in parallel.
2B is an example of a pattern shape composed of two sets of 2b and 2b.

In the case of the electrode pair in the surface heating element 100 illustrated in FIGS. 2 (A) and 2 (B), the electrode pair 21 in the heating layer 10 is composed of straight line segments. It is composed of one zigzag-shaped electrode 21a in the shape of a letter and one comb-shaped electrode 21b having straight branches, and the portion corresponding to the branch of the electrode 21b just enters into the recess of the zigzag electrode. It is a pattern shape. The electrode pair 22 is also similar to the electrode pair 21, but has the opposite shape.

By the way, the first electrode pair 21 and the second electrode pair 22 are formed by, for example, printing conductive ink or laminating conductive foil. As the conductive ink, for example, silver,
Particles of metal or metal oxide such as copper, ITO, tin oxide,
Alternatively, an ink is used in which a conductor powder composed of a flaky foil piece or the like is added to a resin binder as shown in the above-mentioned electrothermal layer. Further, for example, a conductive foil made of the above metal or metal oxide is attached and laminated.

[Base Material Layer] The base material layer 30 (or 30a, 3
0b) is basically not essential, but is preferably one side of the surface heating element for electrical insulation, reinforcement of the surface heating element, and support.
Alternatively, it is laminated on both sides. Therefore, the base material layer is laminated on any one surface or both surfaces of the outermost surface or the outermost surface of the electrothermal layer.

As such a base material layer, a sheet-like material,
A plate-shaped object can be used. As the sheet-shaped base material layer,
A material having electrical insulation and heat resistance, and more preferably nonflammable or flame retardant can be used. For example, it is a sheet of a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polyarylate, and more preferably a biaxially stretched sheet is used. The thickness is not particularly limited, but usually 2
It is about 0 to 300 μm.

As the sheet-like base material layer, a resin sheet or the like made of a fluororesin such as polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, ethylene-4 fluoroethylene copolymer or the like, or silicone Rubber,
Rubber sheets made of rubber such as fluororubber, urethane rubber, SBR (styrene butadiene rubber), EPDM (ethylene propylene diene rubber), NBR (nitrile butadiene rubber), CPE (chlorinated polyethylene rubber), TPE (thermoplastic elastomer) Can be used.

Further, as the sheet-like base material layer, a flame-retardant non-woven fabric or woven fabric (for example, one made of fibers such as glass, asbestos and quartz) or a vinyl chloride resin sheet can be used.

As the plate-shaped base material layer, for example, one made of glass, pottery, porcelain, alumina, phenol resin, various resins listed above as the sheet-shaped base material layer, or the like can be used.

[Insulating Layer] When it is necessary not to heat the electrothermal layer at the portion where the electrode terminal of the electrode pair is taken out, an insulating layer is formed at that portion, and then the electrode pair is formed on the insulating layer. Is preferably formed and used as an electrode terminal lead-out portion.
The insulating layer can prevent current leakage between the electrothermal layer and the electrode pair at the electrode terminal extraction portion. Also, the insulating layer is
In order to insulate the electric heating layer and the electrode pair, they may be formed so as to cover them.

The insulating layer is made of a material having heat resistance that does not cause strength deterioration, deformation, melting, alteration, combustion, etc. during a desired use time. For example, a sheet made of a polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, ethylene-terephthalate-isophthalate copolymer, polyarylate, etc., and preferably a biaxially stretched sheet is used. Alternatively, a resin sheet made of a fluororesin such as polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, ethylene-4 fluoroethylene copolymer, a polyimide resin, or the like can be used. To impart flame retardancy,
A flame retardant may be added to these resins. As the flame retardant, aluminum hydroxide, magnesium hydroxide, molybdenum oxide, diantimony trioxide, etc. are used. Also,
The insulating layer may be formed by adhering the previously formed resin sheet to the electrothermal layer by a method such as heat fusion or dry lamination. Alternatively, a desired pattern can be formed by a printing method such as silk screen printing, gravure printing, flexographic printing, offset printing, roll transfer printing and the like. As the resin binder of the ink used, for example, acrylic resin, polyester resin, polyimide resin, silicone resin or the like is used. The insulating layer usually has a thickness of about 20 to 300 μm.

[Heat Generation of Surface Heating Element] By the way, in order to heat the surface heating element, an electric current is passed through the heating layer to generate heat by Joule heat. The power source therefor may be either direct current or alternating current. . In order to keep the calorific value constant, a power source with stabilized current or voltage is preferable. Also,
Of course, separate switches (eg 210 and 2 in FIGS. 5 and 6) that can be opened and closed independently of each other to the heating layer.
20) is attached. Further, in order to prevent short circuit and other overcurrent, it is preferable to install a fuse or a breaker.

As for the power source, as shown in FIGS. 5 and 6, for example, a separate power source is used for each switch, and a current from one common power source is supplied to the heating layers of different parts in each switch. (See, for example, FIGS. 7 and 8).

Next, as a heat generating method of the present invention, a method suitable for causing the above-mentioned surface heating element of the present invention to generate heat will be described.

The heating method of the present invention uses the above-described surface heating element of the present invention as a heating element. First, both the first electrode pair and the second electrode pair are energized to generate heat, and then the heating layer is applied to both electrodes. In the temperature equilibration time when only one of the pair is energized, at a time point earlier than the shorter time, the energization to either one of the two electrode pairs is stopped and the surface heating element is allowed to reach temperature equilibrium. It is a method to reach. By this method, the temperature rise time is shortened without using a power supply using a complicated control circuit,
Fast heat can be obtained.

Next, with reference to FIG. 4, the present heating method will be described in more detail, focusing on the heating timing.

First, as shown in FIG. 4A, the first electrode
The temperature rise characteristic when the heating layer is energized with a specified current
That is, the temperature with respect to (elapsed) time t after the start of energization
The functional relation of degree T is T₁(T), equilibration time in that case,
That is, the heating of only the first electrode pair causes the electric heating layer to reach temperature equilibrium (
Sum) The time to reach the state is t^c ₁, The flatness of the electric heating layer at that time
The equilibrium (saturation) temperature is T^sat ₁And Also, the second electrode pair alone
T is the temperature rise characteristic when the heating layer is energized with a predetermined current.₂
(T), the equilibrium time in that case is t^c ₂, The electric heating layer at that time
Equilibrium (saturation) temperature of T ^sat ₂And In this case,
The equilibrium temperature and the equilibrium time are the current value and the volume specific resistance of the heating layer.
Resistance and specific heat (capacity), thermal conductivity, thickness, width, ambient temperature,
Whether the current is AC or DC, especially if it is AC, its frequency, and
And the dielectric loss tangent of the heating layer at that frequency
Exist.

In the present invention, the respective energizing currents in the first electrode pair and the second electrode pair may be the same or may be different from each other. Further, the volume specific resistance (dielectric loss) and the thickness width of the electrothermal layer portions related to the first electrode pair and the second electrode pair may be the same or different from each other. These conditions may be appropriately selected depending on the application, required characteristics and the like.

On the other hand, both electrodes of the first electrode pair and the second electrode pair
Temperature rise characteristics T when the heating layers are energized at the same time in pairs
_{1 + 2}(T) is as shown in FIG. in this case
Equilibration time is t^c _{1 + 2}, The equilibrium temperature is T^sat _{1 + 2}Is. However
And, of course, T^sat _{1 + 2}> T^sat ₁, And T ^sat _{1 + 2}> T^sat ₂
Becomes

Then, a heating method for shortening the equilibrium time of temperature rise by using the surface heating element of the present invention having the structure as described in FIGS. 1 and 2 will be described with reference to FIG. 4 (C).

First, first, the first and second electrode pairs 2
Energize 1 and 22 simultaneously. As a result, the temperature rising characteristics at the time of rising are similar to the temperature rising characteristics T _{1 + 2} (t) when both electric heating layers are energized, as indicated by the curve OA or OB in the figure. As a matter of course, as compared with the temperature rising characteristics T ₁ (t) and T ₂ (t) when each electric heating layer is energized independently, the rising is faster (that is, the temperature at the same time is higher).

Then, at time t ^x which is earlier than the equilibrium time of the heating layer when the first electrode pair is used and the equilibration time of the heating layer when the second electrode pair is used, either one of the electrode pairs is used. Stop energizing the heating layer. In the figure, the time t ^x ₁ (on the curve) which is earlier than the equilibrium time of the heating layer when energized by the first electrode pair and the equilibration time of the heating layer when energized by the second electrode pair At point A), the energization by the second electrode pair is stopped and the energization by only the first electrode pair is maintained, and at the time t ^x ₂ (point B on the curve), the energization by the first electrode pair is stopped. However, both cases are shown in which only the second electrode pair is energized. Naturally, t ^x ₁ <t
^c ₁ , t ^x ₁ <t ^c ₂ , t ^x ₂ <t ^c ₁ , t ^x ₂ <t ^c ₂ .

After the energization of one electrode pair is stopped, it transits to a transient state and quickly converges to the equilibrium temperature at the time of single energization by the first electrode pair or the second electrode pair. That is, time t
^When the power supply to the heating layer from the second electrode pair is stopped at ^x ₁ (point A), the equilibrium temperature T ^sat ₁ still remains at point A.
Although the temperature is lower than the above, the temperature further continues to rise due to thermal inertia and the amount of heat generated by the electric heating layer due to the energization from the first electrode pair. The temperature rising characteristic of this portion is a transient state T ₁ ^tran (t)
(AD part of the figure). Then, the time t ^c ₁ '(D
At the point), the temperature converges to the original equilibrium temperature T ^sat ₁ of the electric heating layer due to energization by the first electrode pair. Of course, as is clear from the figure,
Since t ^c ₁ ′ <t ^c ₁ , the time for raising the temperature, that is, the equilibrium time is shortened.

Further, when the energization from the first electrode pair is stopped at the time t ^x ₂ (point B), the heat is dissipated at the point B even though the temperature is already above the equilibrium temperature T ^sat _2. By
A temperature drop occurs. The temperature rising characteristic of this portion is a transient state T
₂ ^tran (t) (BC in the figure). Then, at time t ^c ₂ ′ (point C), it converges to the equilibrium temperature T ^sat ₂ that is the original equilibrium of the electric heating layer due to the energization by the second electrode pair. Also in this case, as is clear from the figure, t ^c ₂ '<t ^c ₂ , and the time for temperature rise, that is, the equilibrium time is shortened.

It should be noted that, as in the case of OAD in FIG. 4C, the temperature is allowed to converge without exceeding the equilibrium temperature which is the target value, or as in the case of OBC, the equilibrium temperature which is the target value is exceeded. Whether the temperature is converged depends on the condition setting, and may be selected while taking into consideration the desired temperature control characteristic and other circumstances.
Generally, if the shortening of the equilibrium time (temperature rising time) is prioritized, a form like OBC is adopted. If priority is given not to let the temperature exceed the equilibrium temperature (target value), a form like OAD is adopted. As shown in FIG. 4C, in order to shorten the temperature raising (equilibrium) time, for example, a timer is used to stop a predetermined energization time t ^x ₁ or t ^x _2.
Is set in advance, and the energization from a predetermined electrode pair is stopped by the timer at a predetermined time t ^x ₁ or t ^x ₂ .

[Application of Surface Heating Element] The application of the surface heating element according to the present invention is not particularly limited. For example, floor heating, electric carpet, heating of chairs and seats, consumer applications such as snow melting heaters, piping, It can be used for industrial applications such as keeping the tank warm.

[0058]

The present invention will be further described with reference to Examples and Comparative Examples.

Example 1 A surface heating element 100 having a cross-sectional view as shown in FIG. 1A and a plan view as shown in FIG. 1B was produced as follows. As the base material layer 30, a thickness of 188 μ
As a first electrode pair 21 composed of electrodes 21a and 21b, silver paste (manufactured by Jujo Chemical Co., Ltd., trade name "J") is provided on one surface of a biaxially stretched polyethylene terephthalate sheet of m.
ELCONSH-1 ") is silk screen-printed using a 250 mesh plate and heated in an oven at 150 ° C for 30
Minute, heated and solidified, line width 4mm, distance between electrodes 38m
m and a film thickness of 9 μm were formed. Next, on the surface of the base material layer 30 on which the first electrode pair 21 is formed, under the same formation conditions as the first electrode pair 21, a second electrode 22a and a second electrode 22b are formed so as not to overlap the first electrode pair 21. 2 electrode pairs 22
Was formed. This second electrode pair was formed as an electrode pattern having a line width of 4 mm, a distance between electrodes of 10 mm, and a film thickness of 9 μm.

Next, the first electrode pair 21 and the second electrode pair 22
As described above, conductive carbon paste (manufactured by Jujo Chemical Co., Ltd., trade name "CH-1") is silk screen printed using a 250 mesh plate and then 12 in an oven.
Heated at 0 ℃ for 20 minutes to solidify, length 80mm, width 100
The surface heating element 1 is formed by forming the electrothermal layer 10 having a thickness of 9 mm and a thickness of 9 μm.
I got 00. In addition, since the electrode terminal is provided, the first electrode pair 2
Part of the first and second electrode pairs 22 (length 30 mm),
Overprinting was performed so that the carbon paste was not applied.

The surface heating element 100 obtained as described above.
Had a surface resistance of 20Ω / □, and a terminal resistance of 17Ω for the first electrode pair and 8Ω for the second electrode pair.

In this surface heating element, as shown in FIG.
The power supply cables 310 and 320 are independently connected to the first electrode pair 21 (electrodes 21a and 21b) and the second electrode pair 22 (electrodes 22a and 22b), respectively.
The power supplies 410 and 420 were connected via the. Then, DC 12V is applied from each of the power supplies 410 and 420 to each electrode pair 2
When electricity was applied to Nos. 1 and 22, the electrothermal layer 10 generated Joule heat and increased in temperature. Table 1 shows the results of measuring the change with time of the surface temperature at that time, together with those of Comparative Examples 1 and 2. As a heat generation method, first, the first electrode pair 21 and the second electrode pair 22 are simultaneously energized, and after 30 seconds, the switch 220 is opened to stop energizing the second electrode pair 22, and thereafter, the second electrode pair 22 is stopped. Only one electrode pair 21 side was energized.

Comparative Example 1 With respect to the surface heating element 100 manufactured in Example 1, the heating method is changed from that in Example 1,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the first electrode pair 21 side from the beginning. The results are shown in Table 1.

[Comparative Example 2] With respect to the surface heating element 100 manufactured in Example 1, the heating method is changed from that in Example 1,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the second electrode pair 22 side from the beginning. The results are shown in Table 1.

[0065]

[Table 1]

[Comparison of Results between Example 1 and Comparative Examples 1 and 2] As shown in Table 1, in the heat generating methods of Comparative Examples 1 and 2, the rate of temperature increase is slow and the rate of temperature increase decreases with time. Two
Even after more than a minute, the temperature continues to rise moderately. On the other hand, in the heat generation method of Example 1, the constant temperature was reached after 60 seconds, and the rapid heating property could be improved.

Example 2 A surface heating element 100 having a cross-sectional view as shown in FIG. 2A and a plan view as shown in FIG. 2B was produced as follows. As the base material layer 30, a thickness of 188 μ
As a first electrode pair 21 composed of electrodes 21a and 21b, silver paste (manufactured by Jujo Chemical Co., Ltd., trade name "J") is provided on one surface of a biaxially stretched polyethylene terephthalate sheet of m.
ELCONSH-1 ") is silk screen-printed using a 250 mesh plate and heated in an oven at 150 ° C for 30
Minute, heated and solidified, line width 5mm, distance between electrodes 5mm,
An electrode pattern having a comb shape with a film thickness of 9 μm was formed. Next, on the surface of the base material layer 30 on which the first electrode pair 21 is formed, under the same formation conditions as the first electrode pair 21, a second electrode 22a and a second electrode 22b are formed so as not to overlap the first electrode pair 21. Two electrode pairs 22 were formed. This second electrode pair was formed as a comb-shaped electrode pattern having a line width of 5 mm, a distance between electrodes of 5 mm, and a film thickness of 9 μm.

Next, the first electrode pair 21 and the second electrode pair 22
As described above, conductive carbon paste (manufactured by Jujo Chemical Co., Ltd., trade name "CH-1") is silk screen printed using a 250 mesh plate and then 12 in an oven.
Heated and solidified at 0 ℃ for 20 minutes, length 155mm, width 11
An electrothermal layer 10 having a thickness of 5 mm and a film thickness of 9 μm was formed to obtain a surface heating element 100. In addition, in order to take an electrode terminal, the 1st electrode pair 21 and the 2nd electrode pair 22 were overlap-printed so that a part (length 15mm) might not be covered with carbon paste.

The surface heating element 100 obtained as described above.
Had a surface resistance of 20 Ω / □, and inter-terminal resistance of 20 Ω for the first electrode pair and 21 Ω for the second electrode pair.

In this surface heating element, as shown in FIG.
In each of the first electrode pair 21 and the second electrode pair 22,
Independently connect the power cables 310, 320 to the switches 210,
Power supplies 410 and 420 were connected via 220. Then, when a direct current of 12 V was applied to each of the electrode pairs 21 and 22 from each of the power supplies 410 and 420, the electrothermal layer 10 generated Joule heat and increased in temperature. The results of measuring the time-dependent change of the surface temperature at that time are shown in Table 2 together with the cases of Comparative Examples 3 and 4. As a heat generation method, first, the first electrode pair 21 and the second electrode pair 22 are simultaneously energized, and after 30 seconds, the switch 2
20 was opened to stop energizing the second electrode pair 22, and thereafter, energizing only the first electrode pair 21 side.

[Comparative Example 3] With respect to the surface heating element 100 manufactured in Example 2, the heating method was changed from that in Example 2,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the first electrode pair 21 side from the beginning. The results are shown in Table 2.

[Comparative Example 4] With respect to the surface heating element 100 manufactured in Example 2, the heating method is changed from that in Example 2,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the second electrode pair 22 side from the beginning. The results are shown in Table 2.

[0073]

[Table 2]

[Comparison of Results between Example 2 and Comparative Examples 3 and 4] As shown in Table 2, in the heat generating methods of Comparative Examples 3 and 4, the rate of temperature increase is slow and the rate of temperature increase decreases with time. Three
Even after more than a minute, the temperature continues to rise moderately. On the other hand, in the heat generation method in Example 2, the temperature reached a constant temperature after 120 seconds, and the rapid heating property could be improved.

[Embodiment 3] A surface heating element 100 having a sectional view as shown in FIG. 7A and a plan view as shown in FIG. 7B which also serves as an example of wiring was produced as follows. Note that the cross-sectional view of FIG. 7A is a cross-sectional view taken along the line AA in FIG. 7B. In addition, the produced surface heating element 100 has parallel linear electrodes 21a and 21b on the back surface of the electrothermal layer 10a (downward in the drawing).
Is formed on the surface (side) of the electrothermal layer 10a, the second electrode pair 22 formed of parallel linear electrodes 22a and 22b is formed in parallel to the first electrode pair 21.
Further, on the surface on which the second electrode pair 22 is formed, the electric heating layer 1
The heating layer 10b has a smaller area than 0a and is located inside the first electrode pair 21, and the base layer 30 is provided on the back surface (the back surface) of the heating layer 10a on which the first electrode pair 21 is formed. Is a laminated structure.

First, as the base material layer 30, a thickness of 188 μm
On one surface of the biaxially stretched polyethylene terephthalate sheet, a silver paste (manufactured by Jujo Chemical Co., Ltd. under the trade name "J" is used as the first electrode pair 21 composed of the electrodes 21a and 21b.
ELCON SH-1 ") is silk screen-printed using a 250 mesh plate, and is heated in an oven at 150 ° C. for 30 days.
By heating for 5 minutes to solidify, an electrode pattern having a line width of 5 mm, a length of 145 mm, a distance between electrodes of 50 mm, and a film thickness of 8 μm was formed.

Next, a conductive carbon paste (manufactured by Toyobo Co., Ltd., trade name "DY-280H-3") is similarly silk-screen printed so as to cover the first electrode pair 21, and the same is subjected to 150 in an oven. It was heated and solidified at 30 ° C. for 30 minutes to form an electrothermal layer 10 a having a width of 70 mm, a length of 100 mm and a film thickness of 9 μm. In addition, in order to take the electrode terminal, a part of the first electrode pair 21 (45 mm in length) was overprinted so that the carbon paste was not applied.

Next, so as to cover the electric heating layer 10a,
And, so that the first electrode pair 21 does not overlap and becomes parallel,
Silver paste (Jujo Chemical Co., Ltd., trade name "JEL
CON SH-1 ") is silk-screen printed using a 250 mesh plate, and is heated in an oven at 150 ° C for 30 minutes,
It was heated and solidified to form an electrode pattern having a line width of 5 mm, a length of 130 mm, a distance between electrodes of 30 mm, and a film thickness of 8 μm.

Next, (part of) the heating layer 10a and the second
A conductive carbon paste (manufactured by Toyobo Co., Ltd., trade name “DY-280H-
3 ”) is silk-screened in the same manner and
50 ℃, 30 minutes, heated and solidified, width 50mm, length 1
The second heating layer 10b having a thickness of 00 mm and a thickness of 9 μm was formed to obtain the surface heating element 100. In addition, in order to take an electrode terminal, a part (30 mm in length) of the second electrode pair 22 is
Overprinting was performed so that the carbon paste was not applied.

The surface heating element 100 obtained as described above
Had a surface resistance of 48Ω / □, and a terminal resistance of 28Ω for the first electrode pair and 20Ω for the second electrode pair.

In this surface heating element, as shown in FIG. 7B, independent power cables 310 and 320 are provided for the first electrode pair 21 and the second electrode pair 22, respectively, and the switches 210 and 220 are respectively provided. It was connected to one common power source 400 via. In FIG. 7B, reference numeral 500 is a thermometer,
Reference numeral 510 is the temperature sensor. And the power supply 40
When a direct current of 0 to 12 V was applied to each of the electrode pairs 21 and 22, the laminated electrothermal layers 10a and 10b generated Joule heat and increased in temperature. The results of measuring the time-dependent change of the surface temperature at that time are shown in Table 3 together with the cases of Comparative Examples 5 and 6.
As a heat generation method, first, the first electrode pair 21 and the second
The electrode pair 22 is energized at the same time, and after 30 seconds, the switch 220
To stop energizing the second electrode pair 22, and thereafter
Only the electrode pair 21 side was energized.

[Comparative Example 5] With respect to the surface heating element 100 manufactured in Example 3, the heating method is changed from that in Example 3,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the first electrode pair 21 side from the beginning. The results are shown in Table 3.

[Comparative Example 6] With respect to the surface heating element 100 manufactured in Example 3, the heating method is changed from that in Example 3,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the second electrode pair 22 side from the beginning. The results are shown in Table 3.

[0084]

[Table 3]

[Comparison of Results between Example 3 and Comparative Examples 5 and 6] As shown in Table 3, in the heat generating methods of Comparative Examples 5 and 6, the rate of temperature increase was slow and the rate of temperature increase for 30 seconds after energization was: They were 1.2 ° C./s and 1.3 ° C./s, respectively. In addition, the temperature rising rate decreases with the lapse of time, and even after 8 minutes or more, the temperature is kept rising moderately. On the other hand, in the heat generation method of Example 3, the temperature rising rate was 3.1 ° C./s in the initial 30 seconds, and the temperature reached the constant temperature after 120 seconds, and the rapid heating property could be improved.

[Embodiment 4] A surface heating element 100 having a sectional view as shown in FIGS. 8 (A) and 8 (B) and a plan view as shown in FIG. 8 (C) which also serves as a wiring example is manufactured as follows. did. 8A is a cross-sectional view of the heat generating portion, and FIG. 8B is a cross-sectional view of the electrode terminal lead-out portion. That is, the cross-sectional view of FIG. 8A is a cross-sectional view taken along the line AA of the heating layer portion of FIG. 8C, and the cross-sectional view of FIG. 8B is the same as that of FIG. 8C. FIG. 6 is a cross-sectional view taken along line B-B of the insulating layer portion of FIG.

Further, the surface heating element 100 thus manufactured has the first linear parallel lines on the electric heating layer 10 made of rubber.
The electrode pair 21 and the second electrode pair 22 are formed, and the terminal lead-out portion of each electrode pair has a configuration in which an insulating layer 40 is provided between the electrothermal layer and the electrode pair.

First, on one surface of a conductive silicone rubber sheet containing carbon black (Kureha Elastomer Co., Ltd., trade name "SB70ENK", thickness 200 μm), an insulating paste (Jujo Chemical Co., Ltd. trade name, "JELCON IN-") was used. 15M ") is silk-screened using a 200-mesh plate, and then ultraviolet rays (lamp intensity 120 W / cm ² , metal halide lamp 1 light)
Was irradiated at a conveyor speed of 6 m / min and an irradiation distance of 10 cm to cure the ink to form an insulating layer 40 having a width of 10 cm, a length of 2 cm and a thickness of 18 μm.

Next, as the first electrode pair 21, a silver paste (manufactured by Jujo Chemical Co., Ltd., trade name "JELCON S") was used.
H-1 ") was silk screen printed using a 250 mesh plate and heated in an oven at 150 ° C for 30 minutes for solidification to form an electrode pattern having a line width of 5 mm, a distance between electrodes of 50 mm and a film thickness of 9 µm. .

Next, as the second electrode pair 22, a silver paste (manufactured by Jujo Chemical Co., Ltd. under the trade name "JELCON S" so as to be parallel to the first electrode pair 21 without overlapping.
H-1 ") was silk screen printed using a 250 mesh plate and heated in an oven at 150 ° C for 30 minutes for solidification to form an electrode pattern having a line width of 5 mm, a distance between electrodes of 30 mm and a film thickness of 9 µm. . In addition, a part of each electrode pair, that is, an electrode terminal portion for connecting a power cable was printed so as to overlap the insulating layer 40 [see FIGS. 8 (B) and 8 (C)].

In this surface heating element, as shown in FIG. 8C, independent power cables 310 and 320 are provided to the first electrode pair 21 and the second electrode pair 22, respectively, and the respective switches 210, One common power source 400 via 220
Connected to. Then, when a direct current of 12 V was applied to each of the electrode pairs 21 and 22 from the power supply 400, the electrothermal layer 10 generated Joule heat and increased in temperature. The results of measuring the time-dependent change of the surface temperature at that time are shown in Table 4 together with the cases of Example 5, Comparative Examples 7, 8 and 9. As a heat generation method, first, the first electrode pair 21 and the second electrode pair 22 are simultaneously energized, the energization to the second electrode pair 22 is stopped after 30 seconds, and thereafter, only the first electrode pair 21 side is energized. It was energized. The results are summarized in Table 4.

[Comparative Example 7] With respect to the surface heating element 100 manufactured in Example 4, the heating method was changed from that in Example 4,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the second electrode pair 21 side from the beginning. The results are shown in Table 4.

[Embodiment 5] In Embodiment 4, the shape of the first electrode pair and the second electrode pair is a comb-like pattern shape as illustrated in FIG. 2 and FIG. 6 of Embodiment 2. In Example 4, the electrode terminal lead-out portion is formed via an insulating layer.
Similarly to the above, a surface heating element 100 as shown in FIG. 9 was produced. FIG. 9 (A) is a heat generating portion, which is AA in FIG. 9 (C).
FIG. 9B is a cross-sectional view taken along the line direction, and FIG. 9B is a cross-sectional view taken along the line BB in FIG. Then, similarly to the second embodiment, the first electrode pair 21 and the second electrode pair 22 are simultaneously energized initially by the heating method using wiring as shown in FIG. 9C, and after 30 seconds, the second electrode pair 22 is turned on. To the first electrode pair 21 side only. The results are shown in Table 4.

[Comparative Example 8] With respect to the surface heating element 100 manufactured in Example 5, the heating method is changed from that in Example 5,
The change in surface temperature with time was measured. As a heat generating method, electricity was applied only to the second electrode pair 22 side from the beginning. The results are shown in Table 4.

[Embodiment 6] A sectional view as shown in FIG.
And a plan view as shown in FIG. 10B, which also serves as a wiring example display,
The surface heating element 100 was manufactured as follows. In this surface heating element 100, the electric heating layer 10 is formed on the base material layer 30, and the back surface of the electric heating layer 10 (between the base material layer and the electric heating layer).
In addition, the first electrode pair 21 and the second electrode pair 22, which are parallel straight lines, are formed in parallel with each other.

First, as the base material 30, a glass cloth-containing silicone rubber sheet (Kureha Elastomer Co., Ltd., trade name "R733", thickness 1.5 mm) was used. Paste (manufactured by Jujo Chemical Co., Ltd., trade name "JELCON SH-
1 ") is silk-screen printed using a 250 mesh plate and heated in an oven at 150 ° C for 30 minutes for solidification to give a line width of 5 mm, a length of 145 mm, and an interelectrode distance of 50 m.
m and a film thickness of 8 μm were formed.

Next, as the second electrode pair 22, the silver paste used for the first electrode pair 21 was silk-screen printed in the same manner so as not to overlap with the first electrode pair 21 and to be parallel, and then, in an oven. It was heated and solidified at 150 ° C. for 30 minutes to form an electrode pattern having a line width of 5 mm, a length of 130 mm, a distance between electrodes of 30 mm, and a film thickness of 8 μm.

Next, a conductive carbon paste (manufactured by Toyobo Co., Ltd., trade name "DY-280H-3") was silk-screen printed in the same manner, and was heated in an oven at 150 ° C. for 30 days.
The solid was heated and solidified for a minute to form the electrothermal layer 10 having a width of 50 mm, a length of 100 mm and a film thickness of 9 μm. In addition, in order to take an electrode terminal, a part of the first electrode pair 21 and the second electrode pair 22 (length 30 mm) was overprinted so that the carbon paste was not applied.

In this surface heating element, as shown in FIG. 10 (B), a switch 210 for each of the first electrode pair 21 and the second electrode pair 22 is provided with an independent power cable 310, 320. One common power supply 40 via 220
Connected to 0. Then, when a direct current of 12 V was applied to each of the electrode pairs 21 and 22 from the power supply, the electrothermal layer 10 generated Joule heat to raise the temperature. The first heat generation method is first
The electrode pair 21 and the second electrode pair 22 were simultaneously energized, and after 30 seconds, the energization to the second electrode pair 22 was stopped, and thereafter, only the first electrode pair 21 side was energized. The results are shown in Table 4.

[0100]

[Table 4]

[Comparison between Results of Examples 5 and 6 and Comparative Examples 7 and 8] As shown in Table 4, in the heat generating methods of Comparative Examples 7 and 8, the rate of temperature rise was slow and the rate of temperature rise decreased with time. However, even after 2 minutes or more, the temperature continues to rise moderately. On the other hand, in the heat generation methods of Examples 5 and 6, the constant temperature was reached after 120 seconds, and the rapid heating property could be improved. In addition, in Examples 5 and 6, since the base material layer was not used and rubber was used for the electric heating layer, it also had extensibility.

[0102]

(1) According to the surface heating element of the present invention, the temperature rises quickly in the initial stage of heat generation, and the desired equilibrium temperature can be reached in a short time. Therefore, when it is used for a heating device or the like, a quick heating effect is obtained, and the temperature rising time is short and the rapid heating property is excellent. In addition, it is not necessary to use a special electrothermal material such as a material having PTC characteristics, and by using an ordinary resistor, stable heat generation characteristics can be obtained without deterioration over time due to the effect of repeated thermal expansion of the resin. it can. Further, even if the temperature control circuit is not specially attached, a constant temperature can be maintained by keeping only the current value constant. (2) Further, by forming the base layer on the electrothermal layer, the electrothermal layer can be supported by the base layer and the mechanical strength of the surface heating element can be reinforced.

(3) According to the heat generating method of the present invention,
It is possible to accelerate the rise of the temperature in the initial stage of heat generation and reach the desired equilibrium temperature in a short time. Therefore, when it is used for a heating device or the like, a quick heating effect can be obtained, and thus the temperature rising time can be shortened and a rapid heating property can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view and a plan view showing an embodiment of a surface heating element of the present invention.

2A and 2B are a sectional view and a plan view showing another embodiment of the surface heating element of the present invention.

FIG. 3 is a cross-sectional view showing various forms of examples centering on the layer structure of the surface heating element of the present invention.

FIG. 4 is an explanatory view detailing a heating method according to the present invention.

FIG. 5 is a plan view showing an example of wiring for a heating method of a certain aspect of the surface heating element of the present invention.

FIG. 6 is a plan view showing an example of wiring for a heating method according to another aspect of the surface heating element of the present invention.

7A and 7B are a cross-sectional view and a plan view showing another embodiment of the surface heating element of the present invention (and its wiring example).

8A and 8B are a cross-sectional view and a plan view showing another embodiment of the surface heating element of the present invention (and its wiring example).

9A and 9B are a cross-sectional view and a plan view showing another embodiment of the surface heating element of the present invention (and its wiring example).

10A and 10B are a sectional view and a plan view showing another example of the surface heating element of the present invention (and its wiring example).

[Explanation of symbols]

10, 10a, 10b Electrothermal layer 21 First electrode pair 21a, 21b (First electrode pair) Electrode 22 Second electrode pair 22a, 22b (Second electrode pair) Electrode 30, 30a, 30b Base material layer 40 Insulating layer 100 surface heating element 210, 220 switch 310, 320 power supply cable 400, 410, 420 power supply (DC stabilized power supply, etc.) 500 thermometer (digital thermometer, etc.) 510 temperature sensor T _{1 + 2} ^sat equilibrium temperature T ₁ ^sat equilibrium Temperature T ₂ ^sat Equilibrium temperature

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 3/00 310 H05B 3/00 310A F term (reference) 2D026 CL02 CL03 3K034 AA02 AA03 AA04 AA11 AA15 AA34 BB08 BB13 BC12 BC13 BC16 BC22 BC23 CA02 CA05 CA14 CA17 CA22 HA04 HA09 JA09 3K058 AA02 BA02 BA16 CE02 CE03 CE13 CE19 CE24 3L072 AA01 AB03 AC02 AD13 AD14 AE01 AE03 AF07 AG03

Claims (4)

[Claims] 1. A surface heating element using an electric heating layer that generates heat by Joule heat, so that the first electrode pair and the second electrode pair do not overlap each other in the planar direction, and only the surface of the electric heating layer is provided. Only the back side,
Alternatively, the first electrode pair and the second electrode are formed on both the front surface and the back surface.
A surface heating element in which each pair of electrodes is connected to a power source through a separate switch that can be opened and closed independently. 2. The surface heating element according to claim 1, wherein an electric heating layer is further laminated on the surface of the electric heating layer on which the electrode pair is formed. 3. The surface heating element according to claim 1, which is formed by further laminating a base material layer of an insulating material on any one surface or both surfaces of the outermost surface or the back surface of the electrothermal layer. 4. Using the surface heating element according to claim 1, first, both the first electrode pair and the second electrode pair are energized to generate heat, and then the heating layer is applied to both sides. At a point before the shorter time of the temperature equilibration time when only one of the electrode pairs is energized, the energization of either of the electrode pairs is stopped and the surface heating element is temperature balanced. How to generate heat.