JPH02278687A - Bar-like exothermic body - Google Patents

Abstract

PURPOSE:To utilize an exothermic body for heat insulating in a water tank or a both tub by providing an insulating layer inside a bar-like body, and coating the exothermic body with the insulating layer. CONSTITUTION:An insulating layer 2 is provided outside a bar-like body 1 made of aluminum. The insulating layer 2 is prepared by a heat resistant resin, for example, a resin composition incorporating Al2O3 into a polyimide resin. An exothermic body 3 is disposed outside the insulating layer 2 provided with an electrode terminal 4. The exothermic body 3 is coated with an exothermic film incorporating polyimide resin into globular graphite, followed by heat treatment. The electrode terminal 4 is a Ni-galvanized copper wire network, and is disposed at both ends of the exothermic film. Therefore, the exothermic body can be utilized for heat insulating or heating in a water tank or a bath tub.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rod-shaped heating element, and more particularly to a rod-shaped heating element whose temperature can be self-controlled.

[Conventional technology]

Conventional heating elements are mainly planar, and bar-shaped heating elements have rarely been seen.

One reason for this was that conventional heating elements required uniformity of the coating film, and it was difficult to form a uniform coating film on curved surfaces.

[Problem to be solved by the invention]

Rod-shaped heating elements can be easily used to keep various aquariums warm, such as by throwing them into aquariums, baths, etc., or heating beakers, etc., so they can be used to keep various aquariums at a desired specific temperature. A rod-shaped heating element with various ignition sensitivities that can be maintained would have high utility value, and its appearance is desired.

[Means to solve the problem]

The present inventor has previously developed a conductive exothermic paint (Japanese Patent Application No. 62-263954) containing carbon powder mainly composed of spherical particles with a particle size of 50 J+m or less and a synthetic resin (Japanese Patent Application No. 62-263954) and the paint. A conductive heating element that can self-control its temperature and is made by coating a solid surface of a desired shape with electrode terminals to form a conductive coating (Japanese Patent Application No. 62-263955)
However, as a result of further research on the application of this conductive heating element, we found that a rod-shaped heating element made of a conductive heating element that can self-control its temperature can be easily used to keep water tanks or bathtubs warm. discovered that it is a useful heating element,
This has led to the present invention.

That is, the present invention provides a temperature self-controllable heating element, which is characterized in that a heating element capable of self-temperature control is provided on the inner or outer surface of a rod-shaped object, with or without an insulating layer, and the heating element is covered with an insulating layer. The present invention relates to a tubular heating element, and a rod-shaped heating element characterized in that a heating element capable of self-controlling the temperature is provided inside the tubular object, with or without an insulating layer provided on the inner surface of the thin tubular object.

Materials for rod-like objects and thin tube-like objects include metals such as iron,
Examples include copper, aluminum, stainless steel, lead or alloys, plastics, ceramics, wood, etc. If the rod-like object and thin tube-like object are made of metal, an electrically insulating layer is provided.

The electrical insulating layer is made of heat-resistant resin such as polyimide resin,
Heat-resistant filler such as Al1203ZrO2, S]0 in polyamide resin, epoxy resin, polyfluorocarbon resin, etc.
2. A resin composition in which powders such as M g O, Cr, and 03.5jO3 titanocarbosilane are mixed is used. The mixing ratio of the heat-resistant filler and the heat-resistant resin can be selected arbitrarily, but is i:o, preferably 2 or more, preferably 1:0.7 to 1.8. A heat-resistant filler conducts heat more easily than a resin, but if the resin is less than 0.2, the strength will decrease and it will be difficult to apply. The thickness of the absolute R layer is approximately 0.1 to 11Tll+.

In the case of rods made of plastic, ceramic or wood, there may be no insulating layer.

The temperature self-controllable conductive heating element has electrode terminals provided at desired intervals on the outside of a rod-like object or the inside of a thin tube-like object (if there is an insulating layer, the insulating layer), and has particle diameters of 0.5 μm or more.
It can be obtained by providing a conductive coating film or an injection filler containing a synthetic resin and carbon powder mainly containing particles consisting of spherical bodies of 0.007 zm or less. In the case of a coating, its thickness is 0.1 nw.

~3.0mm. The electrode terminals provided on the board are copper,
It consists of a wire, plate, or net made of aluminum or copper plated with nickel or tin, and is installed on both sides. This heating element may also be made of a substrate surface of a desired shape provided with electrode terminals, or a substrate coated with or impregnated with the same conductive paint as above, and provided inside or outside of the tubular object. You can also do it. This substrate may be made of plastic, ceramics, wood, fiber, paper, metal material coated with electrical insulation, or other materials.

Spherical carbon particles are produced by polycondensation of low-molecular compounds by heat-treating bituminous materials such as coal tar, coal tar pitch, and heavy petroleum oil at a temperature of 350°C to 500°C for a long time using a method such as Tiller. Meso carbon microbeads (meso carbon m1cr) are produced by repeating the reaction, polymerizing them, and separating optically anisotropic spheres from the produced carbon.
Alternatively, it is produced by graphitizing nearly spherical coke, which is carbonized synthetic resin, through heat treatment and reduction at a temperature of several hundred degrees to several thousand degrees Celsius.

In addition, the synthetic resins used include, for example, polyimide resins, polyamide resins, polyphenylene oxide resins, silicone resins, polytitanocarbosilane resins, phenolic resins,
Epoxy resin, polyparaben acid resin, polyurethane resin, polyester resin, polyetheretherkene resin, polyphenylene sulfide resin, polyflon resin,
These include polyolefin resins, vinyl chloride resins, etc., and a resin having a softening temperature or decomposition temperature can be selected depending on the desired target temperature of the coating film.

The proportion of the carbon particles and the synthetic resin binder of the present invention depends on the desired heating temperature and the size of the heating surface.
Various selections are made depending on the type and combination of synthetic resin, etc., but - for boat fishing, 100 parts by weight of carbon powder (hereinafter referred to as parts)
10 to 190 parts, preferably 20 to 60 parts.

If the proportion of synthetic resin is less than 10 parts, a product with a small resistance value and a high-temperature heating element (applicable to those with a wide heating surface) can be obtained, but the coating film strength is insufficient and the temperature coefficient of electrical resistance is low. becomes small and temperature unevenness tends to occur. On the other hand, if the amount of the synthetic resin is 190 parts or more, the current necessary for heat generation cannot be obtained (the resistance value becomes excessive), making it unsuitable for practical temperatures. That is, the electrical resistance value is 0.5 Ω/mouth at room temperature (Ω/mouth represents the electrical resistance value for a square area)
If it is less than 300Ω/mouth, the current will be too low, resulting in an excessively uneven high temperature, and if it exceeds 300Ω/mouth, the current will be insufficient, the power will drop, and it will be difficult to obtain the desired temperature.

A hardening agent can also be added to facilitate dry assimilation or hardening of the paint or paste in a short time. These curing agents can be selected depending on the resin, and common curing agents such as aliphatic or aromatic polyamines, polyisocyanes, polyamides, amines, thioureas, and acid anhydrides are used.

In addition, stabilizers, plasticizers, antioxidants, etc. may be used as appropriate.

In the case of a large heat generating surface, 1 at normal temperature with low electrical resistance.
If the area is small, a resistor with a high electrical resistance of 250Ω/hole at room temperature is used, and generally a material with an intermediate value is used. In addition, in the present invention, the surface temperature of the heating element can be adjusted to any temperature up to about 450°C by combining the graphite size, heat treatment temperature, paint composition, coating thickness, applied voltage, etc.
It can be obtained stably for a long time (at an environmental temperature of -30°C to +40°C). The curing temperature is 70-200°C.

In the case of the rod-shaped heating element of the present invention, the temperature of the heating element is approximately 200°
It can be stably maintained at a desired specific temperature of C or lower for a long period of time. For example, 20 to 80 for a rod-shaped heating element for heat retention.
℃, and a rod-shaped heating element for heating is adjusted to 80 to 200°C.

The paint mainly composed of carbon particles and synthetic resin can be applied using various coating methods or injection methods, such as brush coating, roller coating, spray coating, electrostatic coating, electrodeposition coating, or powder coating. Other additives or auxiliaries can be added to the agent or depending on the application.

These additives and auxiliaries can be, for example, diluting solvents, anti-settling agents or dispersants, antioxidants, other pigments and other necessary additives.

The thickness of the conductive exothermic coating film is not limited to 0,3 n+m.
~7 mn is appropriate.

The heating element of the present invention is temperature self-controllable and exhibits an increase in electrical resistance at a certain temperature and a sharp increase in the temperature coefficient of electrical resistance (FIG. 2).

The outside of the heating element is covered with an insulating layer. This insulating layer may be the same as the above-mentioned insulating layer, and may be made of a mixture of heat-resistant resin and heat-resistant filler, and may have the same thickness.

Further, in the present invention, a heating element can be embedded inside a thin tube to form a rod-shaped heating element.

The rod-shaped heating element of the present invention can be used for keeping warm and heating water tanks, bathtubs, etc., and can also be used to insert the rod-shaped heating element into the center of a pipe and heat the fluid in that space. can.

[Effect]

The rod-shaped heating element of the present invention does not require any other means or operations, and uses a temperature self-controllable heating element that can constantly maintain a specific temperature, so it can be safely and effectively kept and heated. Become.

〔Example〕

Examples of the present invention will be described below with reference to the drawings, but the present invention is not limited to these examples.

Dog] 11Y FIG. 1 shows a rod-shaped heating element of the present invention. In Figure 1,
Reference numeral 1 denotes a rod-shaped object (100 mmφ) made of aluminum (or copper, iron, stainless steel, plastics, ceramics, wood, etc.), and an insulating layer 2 is provided on the outside of the rod-shaped object.

The insulating layer 2 is made of heat-resistant resin, such as polyimide resin and Al2.
O2 by weight ratio of 1:0.2 or more, preferably 1
:1 mm in film thickness. A heating element 3 is installed outside the insulating layer. The heating element 3 has electrode terminals 4 provided on the insulating layer, and a heating coating film made of a mixture of 0.33 parts by weight of polyimide resin and 1 part by weight of spheroidal graphite having a diameter of 10 to 20 μm is applied to a thickness of 3 U+. It is made of a coated material and is heat treated at around 200°C. The electrode terminals are Ni-plated copper wire nets of 0.2 to 1 nm+φ, which are provided at both ends of the heat-generating coating.

This heating element shows the temperature-resistance curve shown in Figure 2, and has a temperature resistance curve of 20
It showed a characteristic that the electrical resistance rapidly increased at 0°C.

The time-temperature curve of the tubular heating element equipped with this heating element is the third
As shown in the figure, it showed a constant temperature after a certain time.

As shown in Figure 4, the plastic filter 11 (6) (
An electrode terminal (4) is provided on the PET film (4th (B)
) and 4(E)], spherical graphite particles with an average particle diameter of approximately 30 μmφ], 100 parts by weight of a one-component epoxy resin (containing 40 to 50 parts by weight of a curing agent) was blended with 00 parts by weight. A film-like heating element is made by applying a heat-generating paint and covering a plastic film with a heat-generating film with an insulating layer (same insulating paint as in Example 1), and attaching it to a metal rod (LOOmmφ).
A tubular heating element was obtained by winding and fixing it around the outside of the
Figure A) and Figure 4 (D)].

The time-temperature curve of this rod-shaped heating element is 65°C after 55 minutes.
temperature.

An electrode terminal made of a nickel-plated copper wire was attached to the inside of polyvinyl chloride (inner diameter 4 nwn, wall thickness 21'In, length 10ai), and then per part by weight of spherical graphite particles of 10 to 20 μmφ A rod-shaped heating element was manufactured by injecting a mixture of 2 parts by weight of vinyl chloride resin. This heating element exhibited the characteristic that the electrical resistance rapidly increased at 50°C.

Since the tubular heating element of the present invention is equipped with a heating element that can self-control its temperature, it does not require any means such as a thermostat, that is, it does not require any other means, and its temperature can be kept constant. It is a highly practical rod-shaped heating element that can be used for keeping warm or heating water tanks, bathtubs, etc., and is highly safe and inexpensive.

[Brief explanation of drawings]

FIG. 1 shows a rod-shaped heating element obtained in Example 1 of the present invention, FIG. 1(A) is a cross-sectional view thereof, FIG. Figure 2 is a temperature-low particle curve diagram of the rod-shaped heating element of the present invention, Figure 3 is a time-temperature curve diagram of the rod-shaped heating element of the invention, and Figure 4 is the rod-shaped heating element obtained in Example 2 of the invention. 4(A) and 4(D) are schematic diagrams of a rod-shaped heating element, FIG. 4(B) and 4(E) are schematic plan views of a film-shaped heating element, and FIG. (C) is a schematic cross-sectional view of the film-like heating element. 1 is a rod-shaped object, 2 is an insulating layer, 3 is a heating element, 4 is an electrode terminal, 5 is an insulating layer, and 6 is a plastic film base material.

Claims (5)

[Claims] (1) A rod-shaped heating element capable of self-temperature control, characterized in that a heating element capable of self-temperature control is provided with or without an insulating layer on the outer surface of the rod-shaped object, and the heating element is covered with an insulating layer. (2) A heating element capable of self-controllable temperature is provided with an electrode terminal, and a conductive coating film containing a synthetic resin and carbon powder mainly containing particles consisting of spherical bodies with a particle size of 0.5 μm or more and 500 μm or less is formed. The rod-shaped heating element according to claim 1, which is a heating element. (3) A conductive coating film containing a synthetic resin and carbon powder mainly containing particles consisting of spherical bodies with a particle size of 0.5 μm or more and 500 μm or less is applied to a substrate on which a temperature self-controllable heating element is provided with an electrode terminal. 2. The rod-shaped heating element according to claim 1, which is a heating element comprising a heating element provided therein. (4) A rod-shaped heating element characterized in that a heating element capable of self-controlling the temperature is provided inside the thin tubular object, with or without an insulating layer provided on the inner surface of the thin tubular object. (5) A heating element capable of self-controllable temperature is provided with an electrode terminal, and a conductive paste containing synthetic resin and carbon powder containing mainly spherical particles with a particle diameter of 0.5 μm or more and 500 μm or less is injected into the pipe. The rod-shaped heating element according to claim 4, which is a heating element formed by filling.