JPH0539003A - Heating sheet body - Google Patents

Abstract

PURPOSE:To provide a heating sheet body which can heat uniformly over the whole surface. CONSTITUTION:Paired electrodes are disposed over synthetic resin material, preferably over the face of a resistance exothermic sheet 12 made of crystalline resin in which conductive material is uniformly dispersed, and an insulating cover 14 covering the paired electrodes is provided. The sheet can easily be bonded onto a heated body 16, when determined necessary, by providing a pressure sensitive adhesive layer 15 for the outer surface layer of the aforesaid resistance exothermic sheet 12. By this constitution, the sheet is furnished with characteristics free from heat and electricity, and is concurrently excellent in mass productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-generating sheet body capable of uniformly generating heat in the area occupied by the heat-generating sheet body.

[0002]

2. Description of the Related Art A plate-like body having a smooth surface, for example, a rearview mirror of a vehicle is kept at a required temperature to prevent water from adhering to the surface, or to evaporate water droplets attached to the body.
It is widely practiced to prevent functional deterioration of mirrors.

In order to keep the temperature of the rear-view mirror as an example in the required range, whether the rear-view mirror is a flat mirror or a curved mirror, it is formed on a mirror surface as shown in FIG. It is heated from the back side of the surface.

In the conventional example as shown in FIG. 6, the mirror surface 1
A heat-generating ink layer 3 is formed by applying heat-generating ink having conductivity to the rear surface of the mirror 2 having a heat-generating ink, and a pair of electrodes 4 and 4 ′ is provided on the surface of the heat-generating ink layer 3. ing.

Electrode lead wires 6 are connected to the electrodes 4 and 4'via conductive adhesives 5, respectively, and penetrate the heat-generating ink layer 3 and the insulating cover 7 provided to cover the electrodes 4 and 4 '. The electrode lead wire 6 is extended to the outside.

When the electrode lead wire 6 led out to the outside is connected to an appropriate power source outside and is energized, the heat generating ink layer 3 forming a closed circuit together with the electrodes 4 and 4'resistively generates heat, and the generated heat is generated. Is given to the mirror 2.

[0007]

In the conventional example as described above, when the heat generating means is attached to the mirror 1,
Formation of the heat-generating ink layer 3, installation of the pair of electrodes 4, 4 ', coating with an insulating cover 7, and electrode lead wire 6 provided through the insulating cover 7 provided as a coating.
However, there is a problem in that the mounting of each of the mirrors 1 is carried out one by one in a fixed order, and mass production is difficult.

Further, in the processing step of forming the heat-generating ink layer 3 with the heat-generating ink, the fluidity of the heat-generating ink causes uneven layer thickness after coating and drying. As a result, the resistance value of the heating ink layer 3 is not uniform in each area,
There is a problem that uniform heat generation cannot be obtained over the entire area of the heat-generating ink layer 3.

The present invention solves such a problem, has a structure that can be easily mass-produced, and evenly generates heat over the entire area of the heat-generating portion, so that the objects to be joined have a uniform temperature. The purpose of the present invention is to provide a heat-generating sheet body capable of stably providing heat.

[0010]

In order to achieve the above-mentioned object, the heat-generating sheet body of the present invention comprises: (a) a resistance heat-generating sheet formed by spreading a synthetic resin material containing a conductive material; b) A pair of electrodes that keeps the surface of the resistance heating sheet insulated from each other, and brings the resistance heating sheet into an energized state; and (c) covers the pair of electrodes and protects the surface where the electrodes of the resistance heating sheet are installed. It is characterized by having an insulating cover to cover it.

Regarding the resistance heating sheet used in the present invention, the thermoplastic synthetic resin is poor in stability in that it softens due to a change in temperature and in some cases partially melts, and also the thermosetting synthetic resin. Has poor dispersibility when kneading a conductive material. Therefore, a polyester-based crystalline synthetic resin is suitable, and polybutylene terephthalate or polyacetal is preferably used.

The conductive material for forming the resistance heating sheet by kneading with the crystalline synthetic resin is fine carbonaceous material such as carbon black or Ketjenblack, and metallic material such as nickel powder. Used.

A required amount of these conductive materials is kneaded in the crystalline synthetic resin, and a resistance heating sheet having a volume resistivity in the range of about 10 ² to 10 ⁵ Ωcm is formed by means such as extrusion molding. To be done.

On the surface of the resistance heating sheet as described above, a pair of electrodes electrically connected to the resistance heating sheet and provided in an insulated state from each other are provided by printing a conductive ink by a silk screen method. Preferably.

It is a preferred embodiment that the pattern of the pair of electrodes thus provided on the surface of the resistance heating sheet is formed in a comb shape, and that the comb-shaped electrodes are combined with each other. Alternatively, a pair of electrodes may be provided on both sides of the resistance heating sheet.

In the heat generating sheet according to the present invention, one surface side of the resistance heat generating sheet is surface-bonded to an object to be heated,
Since the object to be heated is given heat, providing a pressure-sensitive adhesive layer in advance on one surface side of the resistance heating sheet contributes to the expression of the above-mentioned function.

[0017]

According to the heat generating sheet of the present invention, the resistance heat generating sheet is a crystalline synthetic resin, for example, polyethylene terephthalate resin, and a fine carbon conductive material such as carbon black or a metal conductive material such as nickel powder is kneaded. And are evenly dispersed.

Once formed into a sheet, the crystalline synthetic resin has not only temperature stability but also electrical stability. As a result, it is possible to obtain a resistance heating sheet having a uniform volume electrical resistivity in each part, and this resistance heating sheet is stable against temperature changes and has a low expansion / contraction rate, and has excellent temperature characteristics and durability. It has become a body.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. The heat generating sheet 11 according to the present invention is shown in FIG.
Resistance heating sheet as its cross section is shown schematically
A pair of electrodes 13 and 13 'are in electrical contact with each other on one surface (the lower surface side in FIG. 1) of 12 and are provided in an insulated state from each other, and further cover the electrodes 13 and 13'. Then, the insulating cover 14 is arranged to basically configure the structure.

Electrode 13 and electrode 1 of resistance heating sheet 12
The pressure-sensitive adhesive layer 1 is provided on the other surface opposite to the surface provided with 3 '.
By providing 5, the heat generating sheet body 11 can be bonded to a required surface area of the body to be heated 16 such as a mirror.

Further, in the heat generating sheet body 11 according to the present invention, the resistance heat generating sheet 12 is locally enlarged as shown in FIGS. 1 and 2, and the electrode 13 and the electrode 13 'are formed in this enlarged area. Is guided to form the insert portion 17.

The insert portion 17 is connected to a connector 19 which is connected to an external power source 18 so that a voltage of, for example, DC 12V, DC 24V or AC 100V is supplied to the heat generating sheet 11 from the external power source 18. Therefore, a closed circuit of [external power source 18-electrode 13-resistance heating sheet 12-electrode 13'-external power source 18] is formed.

In the resistance heating sheet 12 of the present invention, polybutylene terephthalate is used as a base material in this embodiment for the purpose of developing the characteristics of the crystalline synthetic resin.

This kind of crystalline synthetic resin is a suitable material without the defect in characteristics as seen in the above-mentioned thermoplastic synthetic resin or thermosetting resin.

After adding a conductive material to the polybutylene terephthalate in an amount corresponding to a desired volume electrical resistivity of about 10 ² to 10 ⁵ Ωcm, and mixing with a ribbon kneader or a fret mill. Kneading with a three-roll mill to sufficiently diffuse the conductive material into polyethylene terephthalate.

During the kneading with the three rolls, the crystalline synthetic resin temporarily exhibits thermoplasticity, and the conductive material is crystallized by the contact pressure between the rolls or the setting of three roll rotation speeds different from each other. A state of being uniformly dispersed in the resin is achieved, and then the sheet is extruded into a sheet having a thickness of 50 to 500 μm to obtain a resistance heating sheet 12 having excellent temperature characteristics and electrical characteristics.

Although carbon black is used as the conductive material in this embodiment, it is needless to say that as another embodiment, Ketjen black or nickel powder, or these conductive materials can be used in combination. Nor.

The electrode 13 and the electrode 13 ′, which are provided so as to be electrically connected to the surface of the resistance heating sheet 12, and which form a pair, are prepared by blending conductive carbon and silver fine powder in an olefin-based or acrylic-based binder. Is formed by printing a conductive ink having conductivity with the silk screen method.

The pattern in which the pair of electrodes 13 and 13 'are provided on the surface of the resistance heating sheet 12 is comb-shaped as shown in FIG. 3 or 4, and each comb-shaped electrode is formed. Even though they are mixed together, the pattern is such that they are kept insulated from each other.

In the electrode pattern shown in FIG. 3, the gap between the electrodes 13 and 13 'is 8 mm, and in the electrode pattern shown in FIG. 4, the gap between the electrodes 13 and 13' is 3 mm,
The thickness of the electrode installed on the surface of the resistance heating sheet 12 is about 15μ.
It is m.

The electrode pattern as shown in FIG. 3 or FIG. 4 corresponds to the volume electric resistivity of the resistance heating sheet 12 on which these electrodes are installed and / or the voltage value or current value applied to these electrodes. The electrode pattern is not limited to the electrode pattern illustrated in FIG. 3 or FIG.
3'may be provided on the front and back sides of the resistance heating sheet 12, respectively.

When the electrode 13 and the electrode 13 'are provided on the front and back sides of the resistance heating sheet 12, respectively, the comb-teeth-shaped electrode 13 and the electrode 13' are formed as shown in FIG. 5A. The resistance heating sheets 12 may be arranged in a zigzag pattern on the front and back sides, or may be arranged facing each other on the same front and back sides as illustrated in FIG. 5 (B).

When the electrodes 13 and the electrodes 13 'are arranged on both front and back surfaces of the resistance heating sheet 12, it is effective to make each electrode a flat plate shape instead of a comb tooth shape in terms of simplification of the construction method. It is a form.

As described above, when the electrode 13 and the electrode 13 'are installed on the resistance heating sheet 12, the resistance heating sheet 12 is previously set to, for example, 300 mm × 10 as a preferred embodiment of the present invention.
A large size of 00 mm is formed, and a large number of paired electrodes according to a required pattern are installed on a required surface of the resistance heating sheet having the large size.

Thereafter, the resistance heating sheet size including the insert portion 17 is cut into a pair of electrode units, for example, by press punching, so that the electrodes 13 and 13 'are installed on the sheet surface. The resistance heating sheet 12 having a shape is efficiently formed.

The resistance heating sheet 12 formed into a required shape and having a pair of electrodes provided on the surface thereof has a surface area other than the insert portion 17 connected to the connector 19 reaching from the external power source 18, for example, polyester or An insulating cover 14 made of a synthetic resin material such as acrylic is applied to obtain the heat generating sheet body 11 of the present invention.

The heat-generating sheet body 11 according to the present invention is formed from the insert portion 17 to the pair of electrodes 13 and 13 'such as DC12.
Approx. 40 〜 by applying voltage of 〜24V or AC100V
It is possible to generate an amount of heat that reaches a temperature in the range of 110 ° C.

Therefore, the heat generating sheet body 11 according to the present invention.
Is through the pressure-sensitive adhesive layer 15 provided on the other surface,
When bonded to the back surface of the mirror as the heated body 16,
It is possible to raise the temperature of the mirror mirror surface to a temperature within the above range, prevent water from adhering to the mirror surface, and further evaporate the adhered water droplets.

[0039]

EFFECTS OF THE INVENTION Since the present invention has the above-described structure, (1) the resistance heating sheet has excellent temperature characteristics and electrical characteristics, so that uniform heat generation is achieved over the entire area of the heating sheet body. Obtained, (2) After extruding the resistance heating sheet into a large format and installing a large number of electrodes at once,
Excellent in mass productivity because it can be cut into the required shape, (3)
It is easy to connect to an external power source, and (4) when the object to be heated is a mirror or other fragile material, it has a function of backing and reinforcing the object to be heated.

[Brief description of drawings]

FIG. 1 is a sectional explanatory view schematically showing an embodiment of the present invention.

FIG. 2 is an enlarged plan view of an essential part showing an insert part.

FIG. 3 is a diagram showing an example of an electrode pattern.

FIG. 4 is a diagram showing an example of an electrode pattern.

5 (A) and 5 (B) are enlarged plan views showing the arrangement of electrodes and the insert portion in another embodiment.

FIG. 6 is a cross-sectional explanatory view schematically showing a conventional example.

[Explanation of symbols]

 1 mirror surface 2 mirror 3 exothermic ink layer 4, 4'electrode 5 conductive adhesive 6 electrode lead wire 7 insulating cover 11 exothermic sheet body 12 resistive exothermic sheet 13, 13 'electrode 14 insulating cover 15 pressure-sensitive adhesive layer 16 heated Body 17 Insert 18 External power supply 19 Connector

Claims (8)

[Claims] 1. A resistance heating sheet formed by spreading a synthetic resin material containing a conductive material, and (b) keeping the surface of the resistance heating sheet insulated from each other and generating the resistance heating. A heat-generating sheet body, comprising: a pair of electrodes that bring the sheet to a conductive state; and (c) an insulating cover that covers the pair of electrodes and covers an electrode installation surface of the resistance heat-generating sheet. 2. The heating sheet body according to claim 1, wherein a pressure-sensitive adhesive layer is provided on a surface layer surface of the resistance heating sheet. 3. The heat generating sheet body according to claim 1, wherein the synthetic resinous material used for the resistance heat generating sheet is a crystalline polyester synthetic resin. 4. The heating sheet body according to claim 3, wherein the crystalline synthetic resin is selected from polybutylene terephthalate, polyacetal and other polyester polymer compounds. 5. The heating sheet body according to claim 1, wherein the conductive material contained in the resistance heating sheet is selected from a fine carbon-based material and / or a metal-based material. 6. The heating sheet body according to claim 1, wherein the resistance heating sheet has a volume electric resistivity in the range of about 10 ² to 10 ⁵ Ωcm. 7. The heating sheet body according to claim 1, wherein the pair of electrodes are each formed in a comb shape. 8. The heating sheet body according to claim 6, wherein the pair of electrodes formed in a comb-like shape is provided by printing by a silk screen method using a conductive ink.