JPS63138683A - Panel heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a sheet heating element.

Many years have passed since the development of a fixed-resistance sheet heating element mainly made of carbon, and since then self-temperature control types have been added and are rapidly becoming commonplace. Its features include a fast temperature rise rate after energization and low power consumption, so it is used in industry and homes.

This type of sheet heating element had the excellent features mentioned above and was expected to become popular, but the film-forming technology was not sufficient, resulting in a number of burnout accidents and fire accidents.

Planar heating elements, not only self-temperature control types, are desired to have a uniform temperature distribution, a wide operating temperature range, and to be able to be used for long periods of time, especially at high temperatures of /θO℃ or higher; The heating element uses a synthetic resin base material, so the temperature is 10oC.
As mentioned above, in particular, there are almost no products that can be used for a long time at temperatures higher than /, 3;'O'C, which is one of the reasons for inhibiting the development of planar heating elements.

An example of a conventional sheet heating element will be explained with reference to FIG.
After screen-printing a commercially available silver paste on the surface of a polyester substrate (1) with a thickness of about 20 μm using an automatic printing machine, it is baked in a conveyor furnace at a temperature of about /♂0°C for about 70 minutes to form a predetermined silver electrode ( 2), screen printed a resistance paste for a heating element on top of it using an automatic printing machine, and then baked it in a conveyor furnace at a temperature of about /♂o℃ for about 70 minutes. A heating resistor layer (3) having a required thickness is formed. The above-mentioned resistance paste for heating elements may be made of, for example, ethylene-vinyl acetate copolymer,
24t2, graphite approximately 72t2 with an average particle size of approximately 2μ
, About alumina powder! 2. About flame retardants! antimony oxide, approx. 2.2. j? , about 4 ttr of anti-aging agent, and about 1/100 F of tetralin were added to a treatment tank equipped with an electric stirrer, and the temperature was maintained at about io0° C. while stirring for about 7 hours, followed by cooling with water.

To remove the heat generating resistor formed as described above, the surface is made of approximately 70% thermosetting phenolic resin to prevent deterioration over time.
After screen-printing a solvent paste containing about 30 g of alumina as the main component, it was placed in a conveyor furnace at a temperature of about 1/1? A phenolic resin surface coating film (4) of a required thickness is provided by baking at 0° C. for about 70 minutes, and a heat-resistant adhesive (4) (5) is placed on top of this coating film to a thickness of about 1/2 cm. A 0μ polyester substrate (6) is crimped using a hot roller or the like to form a heating element, and silver-plated brass terminals (
7) and a lead wire (8) are connected in series.

In the planar heating element formed as described above, if the heating resistor removal (3) is formed non-uniformly, local overheating will occur in the part of the film where the resistance value is abnormally low. The heat-generating resistor melts, and then the opposing polyester substrate melts and thermally decomposes, eventually catching fire and causing a burnout accident. Such accidents are caused by the fact that the sheet heating element is made of a synthetic resin base material that has a relatively low melting point of 3 to 0 degrees Celsius or less and is easily flammable. The occurrence of accidents due to localized overheating caused by homogeneity is further promoted.

In view of the above-mentioned drawbacks of the conventional planar heating element, the inventors have arrived at the present invention as a result of various studies. The present invention uses a base material having an electrically insulating coating film on the surface of a metal foil or plate, and also provides a special electrically insulating coating film on the heating resistor.
In addition, it is formed using a resistance paste for heating elements prepared by a special method to form a planar heating element with extremely homogeneous heating resistor removal as a whole. Even if used continuously for a long time at ℃, there is no occurrence of accidents such as melting or burnout due to local overheating, and it can be used safely and efficiently for a long time.

Hereinafter, the present invention will be described with reference to examples. A silver electrode α2 is provided on the surface of an electrically insulating base material αB, and a heating resistor removal layer is formed by applying a heating element resistance paste or the like on the upper side of this electrode. ) α3 is provided, and an insulating coating film a4 is provided on the upper surface of the heating resistor to form a heating element, and the electrode is connected to the lead wire 0 via a terminal α force, as required. Furthermore, a two-insulating coating film αG is provided on the entire surface of the heating element to form a planar heating element. In this planar heating element, the base material (1) is a foil made of metal such as aluminum, copper, brass, silver, iron, stainless steel, etc., with a thickness of about 0.0 μm or a thickness of about 0.00 μm. Organometallic compound on the surface of the board of j ~ 10 trrm,
For example, it is immersed in a liquid containing organosilsesquioxitin, ethyl silicate, polytitanocarbosilane, etc., or coated with the liquid by an appropriate method, and then fired to a required temperature such as the decomposition temperature to form a ceramic insulation coating. Covering film (l
la) is used.

Various organometallic compounds other than those mentioned above can also be selected and used.

Said insulating coating film Q4. Q5 is also formed by coating the insulating film with a solvent solution of a metal-organic compound or other containing liquid in the same manner as the above-mentioned insulating film, and then baking it in the same manner, resulting in a heat-resistant, chemical-resistant, and durable insulating coating.

The silver electrode 02 can be formed by screen printing a commercially available silver thread conductive paste or the like in a predetermined area and then firing.

As with the conventional method described above, heating resistor removal α3 is performed using conductive material powders such as carbon or metal powders, alumina, antimony oxide and other ceramic material powders, synthetic resin binders, flame retardants, anti-aging agents, etc. The required amount of each was added to a treatment tank with a stirrer together with the required amount of tetralin or other solvent containing or not containing a surfactant, and the temperature was kept at about 100°C while stirring for about 7 hours, and then cooled with water. It can be formed using a resistance paste for heating elements. Also,
There are also resistance pastes for heating elements prepared by the following special method. That is, a conductive material such as graphite, carbon black, or metal made into ultrafine particles with an average particle diameter of about 7 microns or less, preferably on the order of submicrons, and alumina, antimony oxide, or other ceramics in a solvent such as xylene, calpitol, tetralin, or decalin. Materials insoluble in the above solvents such as synthetic materials, synthetic resin binders, flame retardants,
1. Add the required amount of anti-aging agent and other ingredients to a treatment tank with an agitator, maintain the temperature at about 700°C while stirring, and treat for a certain period of time, for example, about 7 hours, and then apply ultrasonic waves. It is prepared by applying no pressure or applying ultrasonic waves for an appropriate period of time, and then rapidly cooling it. The heat generating resistor paste prepared in this way has extremely good uniformity and stability, and the formed heat generating resistor can be removed uniformly, thereby further preventing localized overheating. In the above case, if the materials added to the solvent are added as follows, a paste with even better uniformity and stability can be obtained.

That is, a conductive material in the form of ultrafine particles and a material insoluble in the solvent, such as a ceramic material, are added to a solvent in order while stirring, and after the addition, ultrasonic waves are applied to this as necessary, and then a binder and a flame retardant are added. It can be prepared by sequentially adding , anti-aging agent, etc. with stirring, applying ultrasonic waves for a certain period of time, and rapidly cooling. The applied ultrasonic waves may often be of a frequency commonly used for cleaning contaminated mechanical parts or other articles.

Examples of the planar heating element of the present invention are shown below. Destructive test (toov, 30 minute impression) on each side, surface temperature difference (/
The maximum temperature difference when measuring the surface temperature distribution after energizing for 00V for 30 minutes) and the estimated life C24tOV (estimated from the change in characteristics after energizing for 0 days) were as shown in Table 7. Furthermore, the relationship between the thickness of the base material and the difference in surface temperature (°C) on each side was as shown in FIG. Note that similar test results for the sheet heating element produced by the conventional method are also shown as a comparative example.

Example: An aluminum foil having a thickness of θ0μ was anodized to form an alumina coating on the surface, and then the coating was sealed to obtain an electrically insulating base material. Screen printing was performed using a commercially available silver paste on a predetermined part of the surface of the base material using an automatic printing machine, and the silver electrodes were provided by baking at approximately /♂0℃ for 70 minutes. - Vinyl acetate copolymer, graphite-based ♂0℃ heating element resistance paste was screen printed to a predetermined thickness using an automatic printing machine, and then
It was fired for 70 minutes at 2♂~//J°C to form a heating resistor. Next, after attaching a terminal and lead wire to the silver electrode, this is coated with organosilsesquioxane (trade name: glass resin)! It was immersed in a θ-related ethanol solution, taken out, air-dried, and fired at a temperature of 77♂ to /♂2°C for 30 minutes to obtain a planar heating element having a +f+it thermal ceramic coating film on the entire surface.

Example of blending raw materials for manufacturing resistance paste for heating elements Graphite powder /7 Otsu2 (average particle size 2μ) Alumina powder Gu! Antimony oxide powder 22.6N ethylene-vinyl acetate copolymer-2,! y #Flame retardant
Gu! 〃Anti-aging agent Gu3zThe above blended raw materials were added to Tetralin/700f while stirring.
Mix at 00°C/hour i# and cool with water.

Example: Organosilsesquioxane is used as an electrically insulating base material using aluminum foil with a thickness of 200μ. After immersing in the θ chetanol solution, it was pulled out and air-dried, and then heated at a temperature of 200°C for 3
A planar heating element was obtained in the same manner as in Example 1, except that the heating element was fired for 0 minutes and an insulating coating film was provided on the surface.

Example 3 An electrically insulating base material was used in which an insulating coating film was formed by spraying a 20% ethanol solution of polytitanocarbonane on the surface of a 300μ thick aluminum foil and then baking it at a temperature of 250°C for 30 minutes. And instead of organosilsesquiochitin, polytitanocarbosila-n! Example/Except that the insulating coating film was formed on the entire surface by immersing it in a 0-thialcohol solution, air-drying it, and then baking it at a temperature of 260°C for 30 minutes.
A planar heating element was obtained in substantially the same manner as above.

For example, an electrically insulating base material is prepared by spraying an organosilsesquioxane 3θ thialcohol solution on the surface of an aluminum foil with a thickness of 00μ and baking it for 3θ minutes at a temperature of 20θ to 2℃ to form an insulating coating film. of polytitanocarbonrane instead of organosilsesquioxane! A planar heating element was obtained in substantially the same manner as in Example 1, except that it was immersed in a θ-thialcohol solution, air-dried, and then fired at 2!0° C. for 30 minutes to form a ceramic coating film on the entire surface.

example! A 200μ thick aluminum substrate made of ethyl silicate! θ% alcohol solution (- immersed, air-dried,
A planar heating element was obtained in the same manner as in Example G, except that an insulating base material on which an insulating coating film was formed by firing at 200° C. for 30 minutes was used.

Example 2 A planar heating element was obtained in the same manner as in Example 2 except that a colored aluminum substrate having a thickness of 00 μm was used.

Example 2 Implemented except that an electrically insulating base material formed in the same manner as in Example 3 was used on the surface of an aluminum foil with a thickness of 100μ, and a resistance paste for a heating element manufactured by the following method was used. A planar heating element was obtained in substantially the same manner as in Example 3.

Manufacturing example of resistance paste for heating elements Ultrafine alumina powder Gu! l (Average particle size θ, 2μ) Antimony oxide ultrafine powder 22.31 (Average particle size crushed in a mortar o, sμ) Ethylene-vinyl acetate copolymer 22Z〃Flame retardant
Gu! I anti-aging agent
Stir 3N tetralin/♂o0v and add the above blended raw materials while raising the temperature (100℃),
The mixture was mixed with electric stirring at 0° C. for 7 hours, cooled with water while stirring, and left at room temperature for 72 hours to obtain the desired paste.

example! The use of colored aluminum with a thickness of λ00μ,
Except that the resistance paste for the heating element was manufactured by the following method,
A planar heating element was obtained in substantially the same manner as in Example 2. Tetralin/♂0o1 was stirred and heated to 700°C, while the required amounts of graphite, alumina, antimony oxide ultrafine particles, ethylene-vinyl acetate copolymer, flame retardant, and antiaging agent were sequentially added. After continuing to stir at .degree. C. for 7 hours, ultrasonic waves (30 kilohertz) were applied to the mixture for 70 minutes, and the mixture was rapidly cooled to obtain the desired paste.

Example 9 Organosilsesquioxane 3θ thialcohol solution was applied to the surface of a 3θ0μ aluminum substrate, and after air drying, 2!
A planar heating element was obtained in the same manner as in Example ♂, except that an insulating base material on which an insulating coating film was formed by firing at 0° C. for 30 minutes was used.

Example 10 A planar heating element was obtained in the same manner as in Example 1 except that a 4tooμ aluminum substrate was used.

Example // A planar heating element was obtained in the same manner as in Example 9 except that a 600 μm aluminum substrate was used.

Example/2 A planar heating element was obtained in the same manner as in Example except that a 7000 μm aluminum substrate was used.

(Table 1)

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 7 is a schematic cross-sectional view of a conventional planar heating element, FIG. 2 is a schematic cross-sectional view of a planar heating element of the present invention, and FIG. FIG. 3 is a sectional view similar to FIG. 2 showing a modification. αD is the base material, (Ila) is the insulating coating film, a2 is the electrode, Q
3 is the removal of the heating resistor, Q4 and 0e are insulating coatings, 0 is the terminal, αe is the lead wire Patent applicant Ikeda Bussan Co., Ltd. Patent applicant Kei Komobuchi Construction 1 Figure 2 Figure 3 Procedure amendment Book dated 1986

Claims (1)

[Scope of Claims] 1. A planar heating element in which an electrode is provided on the surface of a metal foil or metal plate provided with an electrically insulating coating film, a heating resistor film is provided, and an electrically insulating coating film is formed on the top surface of the heating resistor film. The insulating coating film is a planar heating element formed by providing a coating film of an organometallic compound on the surface and then firing it. 2. A surface heating element in which an electrode is provided on the surface of an electrically insulating base material, a heating resistor is provided on the surface, and an electrically insulating coating is formed thereon, wherein the heating resistor film is formed by ultrafine conductive particles in a solvent. Resistance paste for heating elements is obtained by adding and mixing solvent-insoluble materials such as organic materials and ceramic materials, synthetic resin binders and other compounded materials, and applying or not applying ultrasonic waves to the mixture. A sheet heating element formed by uniformly coating and firing. 3. A planar heating element in which an electrode is provided on the surface of a metal base material provided with an electrically insulating coating, a heating resistor film is provided, and an electrically insulating coating is formed on the upper surface of the heating resistor film, wherein the electrically insulating coating is The film is formed by providing a coating film of an organometallic compound on the surface and then firing it, and the heating resistor film is formed by adding a material insoluble to the solvent, a synthetic resin binder, and other compounded materials in the form of ultrafine particles to a solvent. A planar heating element formed by adding and mixing, applying a resistance paste for a heating element obtained with or without applying ultrasonic waves thereto, and firing.