JP2000123957A - Electrode part for planar heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate production so as to make high volume production possible, and prevent an electrical contact failure during long-term use by jointing an electrode part to a planar heating element through a joint part comprising an anisotropic conductive adhesive. SOLUTION: An electrode part comprises an electrode and a joint part (an anisotropic conductive adhesive layer) to a planar heating element. It is preferable to select the form of the electrode from metallic foil, a metal plate, a metal bar or a metallic wire aggregate. It is preferable that conductive material which is one of components of an anisotropic conductive adhesive contains silver coating of abrasive granular inorganic material. After applying this adhesive to the electrode, a solvent contained in the adhesive is volatilized by heat treatment to form a B-stage coat on the surface of the electrode. The electrode part is then brought into contact with the planar heating element and subjected to heating and pressurizing treatment to attain the diffused junction of the electrode part and planar heating element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrode portion of a sheet heating element. More specifically, the present invention relates to an electrode unit having a feature in a method of joining an electrode unit to a sheet heating element. In addition, the electrode part referred to in the present invention is a concept including an electrode and a bonding portion that connects the planar heating element and the electrode.

[0002]

2. Description of the Related Art A large number of sheet heating elements have been researched and developed so far, and have been put to practical use for heating or as various heating sources, but most of them are organic polymers or rubber-like substances, such as carbon black and graphite. It is based on a material to which conductive fillers such as graphite), carbon fiber, metal powder, and conductive inorganic powder are added. In addition, in consideration of nonflammability and heat resistance, there have been many reports of a mixture of a conductive filler and a mixture of an inorganic substance and a widely used mixture of a conductive filler and an inorganic substance. Known mica heaters are obtained by winding a ribbon-shaped heating element between a pair of mica plates or a plate containing mica and inorganic fibers as main components (obtained by paper-making or coating and heating on a substrate). It is obtained by inserting a heated mica plate or sheet-shaped heating element, heating and pressing. In general, a planar heating element is put into practical use by preparing a heater element (heating element), attaching a pair of metal electrodes for passing an electric current, and covering it with an organic polymer film or the like for insulation.

As described above, in order to use a planar heating element as a heating element for various applications, it is necessary to supply a current from an external power supply in order to uniformly supply electricity to the heating surface and generate uniform heat. It is necessary to provide an electrode, which is usually
Along the opposing sides of the sheet heating element, it is formed over substantially the entire length of the side, and terminals are attached to a part of both electrodes and connected to a power supply.

[0004] The electrode portion of the sheet heating element reported so far or the electrode section including the method of bonding to the sheet heating element is shown below. In the case of a sheet heating element made of rubber or plastic into which conductive fine particles are kneaded, there is a method of directly embedding a metal wire or a metal foil tape in the sheet. In the case of a conductive cloth (cloth) coated or impregnated with a resistance paint, there is a method in which a metal wire or metal foil is sewn, screwed or pasted.

[0005] In the case of a sheet heating element having a conductive film provided on a plastic sheet, metal (metal) plating, metal spraying, application of a conductive paste containing fine metal particles such as silver powder, or a conductive adhesive is used. There is a method of bonding a foil) tape (preferably with a conductive adhesive). In the case of a carbon fiber sheet heating element, a silver paste is applied along opposite sides of the sheet heating element, and the electrode base layer is formed by heating and impregnating the fibrous heating element with silver of a conductor, There is a method in which a copper foil is stuck thereon with a conductive adhesive or the like to form an electrode.

Next, the gist of the main related patents filed in Japan will be described. 1 In the case of a sheet heating element having a thin plastic film provided with a conductive film such as a conductive carbon paint on a thin plastic film, heat curing with a curing agent containing no curing agent on one side of the metal foil for an electrode is performed. A thin layer of a possible thermoplastic resin is provided, and the metal foil is thermocompression-bonded through the thin layer to a conductive coating made of the resin, an excessive hardener of the resin and conductive carbon black, and integrated. I do.

2 JP-A-55-35404 The ohmic electrodes are provided on both end surfaces in the width direction of the sheet-like positive characteristic porcelain (for example, a paste containing silver as a main component is printed and baked), and the ohmic electrode surface is provided. A power supply terminal made of a porous metal body is connected to the heat generating element (the power supply terminal is simply pressed into contact with the ohmic electrode or the power supply terminal and the ohmic electrode are connected by bonding with a heat-resistant conductive adhesive).

[0008] Japanese Patent Application Laid-Open No. 7-288172 [0008] A carbon fiber sheet obtained by forming an electrode base layer impregnated with silver paste on the surface of a carbon fiber-mixed sheet heating element, and laminating a copper foil coated with gold on the electrode base layer Mounting structure for heating element electrodes.

JP-A-8-222355 An insulating substrate having heat resistance and flexibility, and a metal having a pair of circuits which are adhered to the insulating substrate with a thermosetting adhesive and are arranged at a distance from each other. A planar heating element having a foil electrode layer and a positive temperature characteristic resistor layer disposed on a side of the electrode layer opposite to the insulating substrate and joined to the electrode layer. The planar heating element according to (1), further including a terminal having a connection portion crimped and connected by a current-carrying joint to a terminal mounting portion to which the insulating substrate and the electrode layer except for the positive temperature characteristic resistor layer are adhered. .

5 JP-A-9-298084 A silver paste is applied to a part of the surface of a carbon fiber mixed paper, an electrode plate is adhered on the silver paste, and both surfaces of the carbon fiber mixed paper are coated with a synthetic resin coating material. Coating, partially removing the synthetic resin coating material, soldering a connection terminal of a conductive wire to one end of the electrode plate to form a joint, and forming a joint on the front and back of the electrode plate attachment portion including the connection terminal. A method for preventing insulation and waterproofing of electrode joints of carbon fiber mixed paper, wherein a rubber-based sheet is bonded and a heat-resistant thermoplastic resin is coated on the rubber-based sheet.

6 Japanese Patent Application Laid-Open No. 10-106726 (Similar Patent to Japanese Patent Publication No. 56-14222) In a method of manufacturing a sheet heating element, a heating film and an electrode for supplying electricity to the heating film are formed on the surface of an insulating substrate. A step of forming an electrode composed of a thermoplastic resin containing no curing agent and conductive particles on the surface of the insulating base, and a thermoplastic resin and a thermoplastic resin on the surface of the insulating base on which the electrode is formed. A step of heating and forming a heat-generating film composed of a hardener and conductive heat-generating particles.

[0012] In a method of manufacturing a planar heating element in which a heat generating film and an electrode to be energized to the heat generating film are formed on the surface of the insulating base material, the method comprises the steps of: And a step of forming an adhesive film made of conductive particles, a step of thermocompression bonding the surface on which the adhesive film of the electrode is formed on the surface of the insulating substrate, and a step of thermocompression bonding the surface of the electrode on the insulating substrate. And a step of heating and forming a heating film made of a thermoplastic resin, a curing agent for the thermoplastic resin, and conductive heating particles.

From these prior arts, the biggest problem in the electrode section of the sheet heating element is how to ensure the electrical contact between the electrode section and the heating section, and how to make the electrical contact. It is durable to keep it stable, and it can prevent electrical contact failure caused by the difference in thermal expansion during temperature rise, excessive bending of the heating element, or occurrence of electrical contact failure due to external pressure change. It is understood that it is important to prevent the problem and it is a difficult problem to solve. In addition, the electrode part formed by braiding a metal thread as a warp and / or a weft has insufficient strength and lacks flexibility, and since it is physically bonded, there is a variation in the contact surface, and this problem is solved. Not something.

[0014] It is difficult to embed or sew a metal wire on a sheet-like heating element formed in a film shape, and it lacks productivity, and the connection strength between the electrode and the sheet-like heating element is weak.
Since the conductive paste has a small resin ratio, there is a problem that the adhesive strength with the heating element is low. In addition, when the sheet heating element is bent, the contact between the conductive powders deteriorates, the electric resistance of the electrode increases, and the electrode itself generates heat,
In some cases, power cannot be supplied.

In the case of a metal foil tape with a conductive adhesive, the adhesive strength between the heating element and the heating element is weak, and the adhesive is softened as the temperature of the heating element rises. And the contact resistance increases. Also in the other prior art described above, the process is complicated and costly, the contact resistance between the sheet heating element and the electrode cannot be fixed at the time of manufacturing, the contact resistance value is too high, or the long term During use, electrical contact failure occurs, and the contact resistance between the planar heating element and the electrode increases, and there is a problem in that the electrode itself generates heat or in a severe case, the power cannot be supplied.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode portion of a planar heating element which is easy to manufacture, can be mass-produced, and hardly causes electrical contact failure during long-term use. It is.

[0017]

Means for Solving the Problems As a result of intensive studies, the present inventors have solved the above-mentioned problems by joining an electrode to a sheet heating element using an anisotropic conductive adhesive. They have found that they can do this and have completed the present invention. That is, the present invention includes the following inventions.

(1) An electrode portion joined to a sheet heating element via a joining portion made of an anisotropic conductive adhesive. (2) The electrode unit according to (1), wherein the electrode is formed of one selected from a metal foil, a metal plate, a metal rod, and an aggregate of metal wires. (3) The above (1) or (2) obtained by forming a B-stage anisotropic conductive adhesive film on the surface of the electrode, bringing the film into contact with a sheet heating element, and subjecting it to pressure and heat treatment. 2. The electrode unit according to 1.

(4) The electrode part according to any one of (1) to (3), wherein the conductive material which is one of the constituent components of the anisotropic conductive adhesive contains a silver-coated abrasive inorganic material. . (5) forming a film of a B-stage anisotropic conductive adhesive on the surface of an electrode selected from an aggregate of a metal foil, a metal plate, a metal rod, and a metal wire, and bringing it into contact with a sheet heating element; Pressurization·
A method for producing an electrode portion of a planar heating element, which comprises performing a heat treatment.

(6) The method according to the above (5), wherein the conductive substance, which is one of the constituent components of the anisotropic conductive adhesive, contains a silver coating of an abrasive inorganic substance. In addition, the B stage is equivalent to a prepreg in a semi-dry state. Further, the abrasive granular inorganic substance means a granular inorganic substance having a large number of protruding portions with sharp corners on its surface, or an inorganic substance having a shape like a confectionery confectionery.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an electrode portion joined to a sheet heating element via a joining portion made of an anisotropic conductive adhesive, as described above, and a method of manufacturing the same. . Sheet heating element (heating element section) usable in the present invention
Is not particularly limited, such as a sheet, a film, a plate, a woven fabric, and a nonwoven fabric.

When the surface of the planar heating element is not a regular surface (a surface that overlaps with the electrode surface without any gap) suitable for bonding to the electrode, it is necessary to planarize the electrode mounting portion. As one of the methods, there is a method of forming a low-resistance carbon resin film (B-stage) on the surface. The carbon resin film is expanded graphite, graphite whiskers, carbon consisting of a mixture of carbon black and the like, and a matrix according to the properties of the sheet heating element, for example, silicone, or polyimide resin, epoxy resin, phenol resin, polyester resin, It is made of an organic polymer such as a diallyl phthalate resin, a phenoxy resin, an acrylic resin, a polyamide resin, or a urethane resin.
In order to form the carbon resin film on the surface of the electrode, a conductive adhesive composed of a mixture of the carbon, the matrix and the solvent is applied to the surface of the sheet heating element and dried to form a B stage. Further, the mixing ratio of carbon and resin in the conductive adhesive is preferably about 1: 1 (weight basis), and application is performed by continuous screen printing, a coat machine, or the like in actual production.

The electrode portion of the present invention comprises an electrode and a joint (an anisotropic conductive adhesive layer) between the electrode and the planar heating element. The electrode portions are located at both ends along the opposite sides of the sheet heating element, or at both ends and the center, so that two or three terminals can be taken out. The material of the electrode is Cu, Al, N
Among metals such as i and Fe, and various alloys (Ti alloy, stainless steel, etc.), Cu, Al, and Ni are particularly preferable. The shape of the electrode is selected from a metal foil, a metal plate, a metal rod, or an aggregate of metal wires. Roll-to-roll Considering continuous production with rolls (a system that continuously produces unrolled pieces without cutting them), ease of processing technology, and low prices,
As an electrode configuration method, an aggregate of a metal foil and a metal wire is preferred, and a metal foil is most preferred.

In the case of a metal foil, one having a thickness of 5 to 100 μm, preferably 10 to 35 μm is prepared, and the surface thereof is subjected to a treatment for improving the adhesion to the anisotropic conductive adhesive. Is preferred. For example, Cu plating the surface,
Ni plating is applied to form regular convex portions on the surface to improve the adhesion to the anisotropic conductive adhesive. When used at a high temperature, plating is performed with a noble metal such as Au, Pd, Ag, Pt, or Ru to prevent surface oxidation. By these processes, the ohmic property of the joint is maintained.

In the case of an assembly of metal wires, the diameter is 5 to 100.
Those having a thickness of μm arranged in parallel with no gaps are used as electrodes and fixed with an anisotropic conductive adhesive. Since it is difficult to arrange the metal wires in parallel without any gaps, it is preferable to prepare a nonwoven fabric or the like that can be melt-bonded by, for example, heat and pressure treatment for overcoating, and arrange it on it. The most significant feature of the present invention is that an anisotropic conductive adhesive is used for joining an electrode portion and a planar heating element (heating element section).

Next, the components of the anisotropic conductive adhesive used in the present invention will be described. In the present invention, a conductive material which is one of the constituent components of the anisotropic conductive adhesive preferably contains a silver coating of an abrasive inorganic material. The particle size is usually from 5 to 100 μm, preferably from 10 to
It is preferable that the particle size distribution width is as narrow as possible. Examples of the inorganic substance include conductive carbides (carbon compounds), conductive nitrides (nitrogen compounds), and conductive borides (boron compounds). Among them, conductive carbides are preferable, and preferable. SiC, W as carbide
C, MoC, TiC and the like.

The conductive material preferably contains colloidal silver, flake silver, carbon black, graphite, carbon fiber and the like, in addition to the silver coating of the abrasive inorganic material. Each of them has a particle size much smaller than that of the silver-coated abrasive-grained inorganic substance, and is preferably 1/4 or less of that of the silver-coated abrasive-grained inorganic substance.

The matrix, which is another component of the anisotropic conductive adhesive, has an adhesive action, and depends on the temperature at which the sheet heating element is used, such as titanate (organic titanium compound) or silicone. A polymer material or an organic polymer material such as a polyimide resin, an epoxy resin, a phenol resin, a diallyl phthalate resin, a phenoxy resin, an acrylic resin, a polyester resin, a polyamide resin, or a urethane resin is selectively used.

When selecting a matrix,
In addition to the use temperature of the planar heating element, one having a thermal expansion coefficient close to that of the heating element is selected. This prevents floating at the interface during long-term use, and keeps the contact resistance constant. The mixing ratio A: B (weight basis) of the conductive substance (A) and the matrix (B) is preferably 5-55:
It mixes so that it may be set to 45-95, More preferably, it may become 10-30: 70-90. In the conductive material, the mixing ratio (weight basis) of the silver-coated abrasive (C) to the other conductive material (D) is 10 to 40:
It is preferable to be 60 to 90.

The conventionally reported isotropic conductive adhesive contains ohmic material at about 75 to 85% of the whole, so that ohmic bonding can be performed. It is difficult to match the coefficient of thermal expansion with the constituent material, and there is a drawback that the contact resistance increases due to floating at the interface during long-term use. The anisotropic conductive adhesive comprising the conductive substance (A) and the matrix (B) is a paint containing a solvent for coating the electrode material. It is applied to a metal electrode, and then heat-treated to evaporate the solvent to form a B-stage film on the surface of the metal electrode. This film is cured during the pressurization and heat treatment and has an adhesive strength.

In some cases, it is preferable to use a thick layer of the anisotropic conductive adhesive in order to enhance the adhesive strength between the electrode portion and the sheet heating element. In some cases, temporary bonding is required for the post-coating process. In these cases, a film is formed on the surface of the electrode in which a nonwoven fabric, a woven fabric, a perforated sheet, or the like, which can be melt-bonded by heat and pressure, is sandwiched between the anisotropic conductive adhesive layers. To In this case, first, an anisotropic conductive adhesive layer is formed on the surface of the metal electrode by applying the first step, and then the non-woven fabric, woven fabric, or perforated sheet is covered thereon, and further overlaid thereon to form an anisotropic conductive adhesive layer. A conductive adhesive layer is formed. By sandwiching the nonwoven fabric, woven fabric, or perforated sheet, etc., in the middle part, temporary bonding can be performed and the bonding strength with the heating element part is increased. This is advantageous in the case where the electrode portion is continuously attached by using the same. In these treatments, the drying treatment for forming the B-stage film by volatilizing the solvent contained in the anisotropic conductive adhesive is performed after being applied to the metal electrode. I do.

When applying an anisotropic conductive adhesive,
In actual production, continuous screen printing, a coating machine, or the like is used to form a roll-wound electrode. The electrode part obtained by forming the B-stage film of the anisotropic conductive adhesive thus obtained on the surface is cut to a required width for continuous roll-to-roll production and used as a roll (roll). I do. In addition, it can be stored by making it into a roll (roll), but since the pot life is short at normal temperature, it may be stored at a low temperature in some cases to extend the pot life.

It is ideal that the layer of the anisotropic conductive adhesive is controlled to a particle size of the abrasive inorganic substance.
Then, the planar heating element and the electrode can be energized through the silver coating of the abrasive inorganic substance. on the other hand,
Since current is not supplied except in the direction connecting the sheet heating element and the electrode (see FIG. 1), the conductive member becomes anisotropically conductive. The conductive powder contained in the heating element such as colloidal silver, flake silver, and carbon black, graphite, and carbon fiber is dispersed in the matrix, and the silver coating of the abrasive inorganic substance alone generates planar heating. Insufficient contact between body and electrodes,
These fine conductive particles act as current-carrying particles that mediate between them (between the heating element and the silver-coated abrasive-grained inorganic material, and between the silver-coated abrasive-grained inorganic material and the electrode), and assist in surface contact. Has a positive effect. By performing such a treatment, the electrode portion has a small contact resistance and a high adhesion, and has a small change in the contact resistance even when the temperature cycle is repeated, and has a stable ohmic property.

The electrode section having a B-stage film on its surface is brought into contact with a sheet heating element (heating element section) and subjected to heating and pressurizing treatment to form the electrode section and the sheet heating element (heating element section). Diffusion bonding is achieved. The electrode section having a B-stage anisotropic conductive adhesive film on its surface is attached to both ends along the opposite side of the planar heating element, or both ends and the center. The electrode part is overlapped at the designated position of the part, and pressure and heat treatment are performed. The heating may be performed using a microwave internal heater. The conditions of pressurization and heating are determined in consideration of the heat resistance temperature, surface condition, and the like of the electrode section and the heating element section.

In order to attach (join) the electrode portion on which the coating of the anisotropic conductive adhesive of the B stage is formed to the planar heating element (heating element section), industrially, the above-mentioned roll tow is used. Continuous production on rolls is advantageous. As an example, a metal foil tape having a roll (roll) anisotropic conductive adhesive film and a roll (roll) -like sheet heating element are prepared, and are subjected to pressure / heating (roll) treatment, or Further, by performing a drying treatment for curing, an electrode portion joined to the sheet heating element of the present invention via an anisotropic conductive adhesive can be obtained.
In this case, when overcoating or undercoating, a laminate material made of a roll-shaped insulating material is coated on or below a B-stage laminate material, and is subjected to a pressure / heat (roll) treatment. can get.

Terminals can be taken out from the sheet heating element by a method such as soldering, caulking, or brazing according to the shape, heat resistant temperature, application, etc. of the sheet heating element. In taking out the terminal, the electrode part of the present invention can be easily attached with a commercially available terminal, lead wire, temperature haze, temperature controller and the like.

[0037]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. Unless otherwise noted, figures are on a weight basis. (Example 1) A (heating element portion of sheet heating element) First, a sheet (1) was formed and further processed to produce a heating element portion (sheet (2)).

[Production of sheet (1)] (Raw materials) a Carbon fiber: HTA-C6 b manufactured by Toho Rayon Co., Ltd. Swellable layered silicate: Somasif (ME-100, manufactured by Corp Chemical Co., Ltd.) Non-swellable layered silicate: micromica (MK-10)
0, synthetic non-swellable mica manufactured by Corp Chemical Co., Ltd.) d Expanded graphite: Maruyo Seimitsu Co., Ltd., EXP-Ge Glass short fiber: manufactured by Nippon Inorganic Co., Ltd .;
1.5 μm, wire length 1 to 3 mm f Polyamide fiber: Unitika, Apière g Silica sol: Nissan Chemical Co., Ltd., Snowtex U
P The swellable layered silicate used was an 8% by weight aqueous dispersion, and the expanded graphite was a 2% by weight aqueous dispersion.

(Preparation method) 20 parts of a swellable layered silicate (b) and 2 parts of a non-swellable layered silicate (c) in 25,000 parts of water
And 20 parts of expanded graphite (d) were added and mixed, and 15 parts of short glass fiber (e) and 6 parts of polyamide fiber (f) were added thereto.
10 parts of silica sol (g) and the like were added, and finally 9 parts of carbon fiber (a) were added and stirred at high speed to prepare a mixed dispersion. Next, a standard pulp disintegrator (manufactured by Kumagaya Riki Kogyo Co., Ltd.)
The mixture was stirred at a high speed for about 30 minutes in the mixture to uniformly disperse the whole.

Next, water was further added thereto to adjust the solid content concentration to 0.05%, and a coagulant was added while stirring and dispersing with a general-purpose stirrer to coagulate the mixed dispersion. The slurry obtained by coagulation is standard square sheet machine (manufactured by Kumagai Riki Kogyo Co., Ltd., 25 cm square, wire mesh opening 177 μm).
The paper was made. After that, a tumble dryer (Kumaya Riki Kogyo Co., Ltd.)
And dried at about 100 ° C. for several minutes to obtain a sheet (1). The obtained sheet had a porous surface and had a thickness of about 0.2 mm. Next, the sheet obtained as described above is impregnated with a carbon black paint as described below to form a prepreg, and is subjected to a heat and pressure treatment, and is subjected to a heating element (sheet (sheet ( 2)) was made.

[Production of Sheet (2)] (Carbon black paint component) a Carbon black: oil furnace black (# 10B manufactured by Mitsubishi Chemical Corporation) b Matrix: bisallyl nadiimide resin (Maruzen Oil Co., Ltd.) BANI-X) c Solvent: acetone (Preparation of carbon black paint) Matrix 6 described above
0 parts were dissolved in 140 parts of acetone, 40 parts of carbon black was added thereto, and the mixture was treated with a ball mill for 300 hours.
A varnish-like mixture was prepared.

(Preparation method) The sheet (1) was immersed in the carbon black paint to impregnate the sheet (1) with the carbon black paint. Then, at 120 ° C. for 20
After drying for a minute, a prepreg-like sheet (2) was obtained. The obtained sheet was cut into a rectangle of 150 × 120 (mm) and used for the test. B (electrode) First, the surface of a Ni foil having a thickness of 12 μm and a width of 8 mm was approximately 1 μm
Thick Ni plating was used, and the surface thereof was further Au plated to a thickness of about 1 μm.

C (anisotropic conductive adhesive) 1 conductive material Abrasive material: SiC (β-SiC: DU-4M manufactured by Showa Denko KK) is made of Ag, and SiC: Ag = 60:
An amount coated to give a ratio of 40. As for the particle size distribution, the ratio included in the range of 13 to 18 μm is about 90% of the whole. Flaky silver: TCG- manufactured by Tokuriki Chemical Laboratory Co., Ltd.
7. Those having a particle size of 3 μm or less. Colloidal silver: E20 manufactured by Tokuriki Chemical Laboratory Co., Ltd., having a particle size of 1 μm or less. Expanded graphite: EXP-G, Maruho Seiyaku Co., Ltd., particle size about 3μ
m thing. Mixing ratio: ::: = 20: 40: 30: 10

2 Matrix (mixing ratio) Phenol resin: Phenol PR1440M 50 manufactured by Mitsubishi Gas Chemical Co., Ltd. Alicyclic epoxy resin: EHPE 30 manufactured by Daicel Chemical Co., Ltd. Bisallylnadiimide resin: manufactured by Maruzen Oil Co., Ltd. BANI-X15 hardening agent: 2NZA-P53 manufactured by Shikoku Chemicals Co., Ltd. Solvent: carbitol acetate Mixing ratio of conductive substance (A), matrix (B), solvent (C). Conductive substance (A): matrix (B): solvent (C) =
12: 88: 120

D (Method of Forming B-Stage Film of Anisotropic Conductive Adhesive on Electrode) On one surface of the Au-plated Ni foil shown in B (electrode), the surface shown in FIG. The electroconductive adhesive was applied to a thickness of about 80 μm using a bar coder (manufactured by Matsuo Sangyo Co., Ltd.), and dried at 120 ° C. for 10 minutes.
An electrode part having a μm B-stage coating was obtained. In addition,
The thickness of the film was measured with a graduated optical (metal) microscope.

E (Processing method for bonding the electrode having the B-stage film and the heating element of the sheet heating element) The sheet (2) shown in the above A (heating element section of the sheet heating element)
And the electrode portion having the B-stage coating obtained in the above-mentioned process D, using a heat sealing machine manufactured by Nippon Avionics Co., Ltd.
m), press the electrode part on both ends along the opposite side of
The heat treatment (8.2 kg / cm ² , 350 ° C., 30 seconds) was performed. The thickness of the film of the electrode portion made of the anisotropic conductive adhesive was 11 μm as measured by a graduated optical (metal) microscope. Faston terminals were attached to both electrodes of the obtained sheet heating element by caulking, and an electrical characteristic test was performed.

F (Electrical Characteristics Test) When the resistance between the two electrodes of the sheet heating element obtained in E was measured, it was 10.94 ohm at a measured voltage of 0.3 V.
It was 10.93 ohm at 0.03 V, a value with almost no difference. From this, it can be seen that the bonding between the electrode part and the heating element part is an ohmic bonding. The load test was performed with a rated power of 15
Intermittent with W (30 min ON, 10 min OFF repeated) 1
The current was applied for 000 hours, and then the resistance value was measured. The resistance value between the two electrodes was 10.17 ohm at a measurement voltage of 0.3 V and 10.15 V at 0.03 V. Although the resistance value was slightly lower than before the load test, there was almost no difference between the two measurement voltages. It can be seen that ohmic bonding is maintained between the electrode and the heating element.

(Example 2) A (heating element portion of sheet heating element) A polyester nonwoven fabric manufactured by Unicell Corporation (RT0109)
On W), a resistive paint comprising the following mixed components was screen-printed and dried at 150 ° C. for 60 minutes to produce a heating element of a sheet heating element. The heating element based on the obtained nonwoven fabric was cut into a rectangle of 150 × 120 (mm) and used for the test.

(Resistant paint component) 1 Conductive substance Carbon fiber: HTA-C6 carbon black, manufactured by Toho Rayon Co., Ltd., oil furnace black, manufactured by Mitsubishi Chemical Corporation, # 10B Graphite whisker: manufactured by Showa Denko KK , VGC
F Expanded graphite: manufactured by Marutoyo Seimitsu Co., Ltd., EXP-1 Mixing ratio: ::: = 50: 30: 15: 5 2 Matrix: phenoxy resin (YP50 manufactured by Toto Kasei Co., Ltd.) 3 Solvent: carbitol acetate Mixing ratio of conductive substance (A), matrix (B), solvent (C). Conductive substance (A): matrix (B): solvent (C) =
100: 70: 210B (electrode) A Cu foil having a thickness of 12 μm was plated with Au having a thickness of about 1 μm, and cut to a width of 8 mm.

C (anisotropic conductive adhesive) 1 conductive substance Abrasive substance: SiC (β-SiC: DU-4M manufactured by Showa Denko KK) is made of Ag, and SiC: Ag = 60:
An amount coated to give a ratio of 40. The particle size distribution is about 90% in the range of 13 to 18 μm.
%. Flaky silver: TCG- manufactured by Tokuriki Chemical Laboratory Co., Ltd.
7. Those having a particle size of 3 μm or less. Colloidal silver: E20 manufactured by Tokuriki Chemical Laboratory Co., Ltd., having a particle size of 1 μm or less. Expanded graphite: EXP-G, Maruho Seiyaku Co., Ltd., particle size about 3μ
m or less. Mixing ratio: ::: = 20: 50: 20: 10

2 Matrix (mixing ratio) Phenol resin: Phenol PR1440M 60 manufactured by Mitsubishi Gas Chemical Co., Ltd. Epoxy resin: Epofriend manufactured by Daicel Chemical Co., Ltd. 40 3 Solvent: carbitol acetate conductive substance (A), matrix (B), the mixing ratio of the solvent (C). Conductive substance (A): Matrix (B): Solvent (C) = 12: 8
8:60

D (Method of Forming B-Stage Film of Anisotropic Conductive Adhesive on Electrode) On one surface of the Au-plated Cu foil shown in B (electrode), the surface shown in FIG. The electroconductive adhesive was applied to a thickness of about 80 μm using a bar coder (manufactured by Matsuo Sangyo Co., Ltd.), and dried at 120 ° C. for 10 minutes.
An electrode part having a μm B-stage coating was obtained. In addition,
The thickness of the film was measured with a graduated optical (metal) microscope.

E (Processing method for bonding the electrode having the B-stage coating and the heating element of the sheet heating element) Heating element section based on the nonwoven fabric shown in the above A (heating element section of the sheet heating element) And the electrode portion having the B-stage film obtained in the above-mentioned process D, by using a laminating machine manufactured by Taisei Laminator Co., Ltd., and facing the long side (150 mm side) of the heating element portion (rectangle). Pressure and heat treatment (5 kg / cm ² , 180 ° C.) at both ends along the side
(5 m / min). The thickness of the electrode film made of anisotropic conductive adhesive is graduated optical (metal)
It was 10-20 micrometers when measured with the microscope. Faston terminals were attached to both electrodes of the obtained sheet heating element by caulking, and an electrical characteristic test was performed.

F (Electrical Characteristics Test) The resistance between the two electrodes of the sheet heating element obtained in the above E was measured.
It was 129.60 ohms at 3V, a value that was almost the same. From this, it can be seen that the bonding between the electrode part and the heating element part is an ohmic bonding. Load test intermittently at rated power 5W (repeated 30 minutes ON, 10 minutes OFF) 1000
The current was applied for a period of time, and then the resistance was measured. The resistance value between the two electrodes is 120.57 ohms at a measurement voltage of 3 V, and the resistance between the electrodes is 0.15.
At 120.52 V at 03 V, the resistance value was slightly lower than before the load test, but there was almost no difference between the two measured voltages.
It can be seen that the ohmic joint is maintained between the electrode and the heating element.

[0055]

The electrode part of the present invention is joined to a sheet heating element via a joint made of an anisotropic conductive adhesive.
Since the content of the conductive substance, which is a component of the adhesive, is extremely small as compared with the conventional isotropic conductive adhesive, the amount of the matrix of the adhesive component, which is another component, can be greatly increased. it can. For this reason, the amount of adhesive can be reduced, the bonding strength between the electrode and the planar heating element is strengthened, and a firmly fixed electrode portion is formed, so that poor electrical contact hardly occurs during long-term use. In addition, when the conductive material has a special configuration including a silver coating of an abrasive inorganic material, the junction between the planar heating element and the electrode portion has low resistance, and an ohmic junction can be achieved. Further, in the present invention, since a film of an anisotropic conductive adhesive of the B stage is formed on the surface of the electrode portion, and it is brought into contact with the sheet heating element, and can be obtained by pressurizing and heating, It is easy to manufacture and can be mass-produced on a roll-to-roll basis.

[Brief description of the drawings]

FIG. 1, which shows an example of a preferred embodiment of the present invention, is a state diagram of a conductive substance in an anisotropic conductive adhesive for bonding an electrode and a sheet heating element. It conducts through the abrasive conductive material in the figure.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Furusawa 23rd Ichibancho, Chiyoda-ku, Tokyo F-term (reference) 3K092 QA05 QB31 QC02 QC03 QC05 QC07 QC08 QC18 QC20 QC45 QC56 RF02 VV06

Claims (6)

[Claims] 1. An electrode portion joined to a sheet heating element via a joining portion made of an anisotropic conductive adhesive. 2. The electrode unit according to claim 1, wherein the electrode is formed of one selected from a group consisting of a metal foil, a metal plate, a metal rod, and a metal wire. 3. The method according to claim 1, wherein a film of a B-stage anisotropic conductive adhesive is formed on the surface of the electrode, and the film is brought into contact with a planar heating element and subjected to pressure and heat treatment. The electrode part as described. 4. The electrode part according to claim 1, wherein the conductive material, which is one of the constituent components of the anisotropic conductive adhesive, includes a silver coating of an abrasive inorganic material. 5. A B-stage anisotropic conductive adhesive film is formed on the surface of an electrode selected from an aggregate of a metal foil, a metal plate, a metal rod, and a metal wire, and the film is brought into contact with a sheet heating element. And a pressure / heat treatment. 6. The method according to claim 5, wherein the conductive material, which is one of the constituent components of the anisotropic conductive adhesive, includes a silver coating of an abrasive inorganic material.