KR0179417B1 - Self-control type heater and its control method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-regulating heater having improved PTC (positive temperature coefficient) switching characteristics of a heating element, and a method of manufacturing the same, comprising a carbon black, an inorganic filler, and a glass fiber reinforcing agent in a conductive conductor, a crystalline resin, or the crystalline resin. Or a spacer that reduces contact resistance by mixing an antioxidant, a heating element that maintains an equilibrium temperature by controlling electrical resistance even if the ambient temperature decreases or rises, and a conductive coating layer for reducing contact resistance generated between the conductor and the heating element. And a jacket coated on the outer circumferential surface of the heating element and using polyolefin or fluorine resin as it is or mixing polyolefin and fluorine resin with a flame retardant, an inorganic filler, a heat stabilizer or a UV stabilizer, thereby improving PTC characteristics of the heater. Self-controlled heaters and their It relates to a manufacturing method.

Description

Self-regulating heater and its manufacturing method

1 is a perspective view showing a conventional self-regulating heater structure,

2 is a perspective view showing a self-regulating heater of the present invention,

3 is a perspective view showing a spacer,

4 is a graph comparing the PTC characteristics of the resistance to temperature,

5 is a graph comparing the output against temperature.

* Explanation of symbols for main parts of the drawings

20: conductor 22: conductive coating layer

24: spacer 26: heating element

28: jacket

The present invention relates to a self-regulating heater having improved PTC (positive temperature coefficient) switching characteristics of a heating element and a method of manufacturing the same.

In the conventional self-regulating heater, as shown in FIG. 1, the conductor 10 is plated with tin, nickel or silver, and transmits electricity, and the conductor 10 is connected to the connection part so as to maintain a constant interval and the carbon The heating element 12 in which black particles are uniformly dispersed in the polymer matrix resin and the outer circumferential surface of the heating element 12 are coated with polyolefin or fluorine resin, or the polyolefin or fluorine resin is flame retardant, inorganic filler, heat stabilizer or UV-. It consists of the jacket 14 in which stabilizer etc. were mixed.

That is, in the conventional self-regulating heater, Joule heat (I ² R) is generated when electricity is applied to the heating element 12 through the conductor 10, and if the ambient temperature is higher than this, the heating element of the polymer matrix The thermal expansion causes a large gap between the carbon black particles, which makes the electrons difficult to move, thereby increasing resistance and switching. However, the switching by the thermal expansion of the matrix polymer alone has a problem that the time taken to switch is relatively slow.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide a self-regulating heater and a method of manufacturing the same, which improves the PTC characteristics of the heater by increasing the separation between particles by the thermal expansion of the polymer matrix and the thermal expansion of the spacer composite action. It is.

Another object of the present invention is that even if a self-regulating heater is installed in an area where there is a risk of explosion due to leakage of volatile gas and the temperature rises above a specified temperature, it is caused by thermal expansion of the polymer matrix in the heating element, that is, at least 10% of the heating element material. The plastic spacer having a large thermal expansion characteristic is to provide a self-regulating heater and a method of manufacturing the same, which promotes longitudinal expansion between conductors and improves a switching operation, thereby releasing such an explosion risk.

The self-regulating heater for achieving the above object is a spacer that reduces the contact resistance by mixing a conductive conductor, carbon black, inorganic filler, glass fiber reinforcing agent or antioxidant with crystalline resin or the crystalline resin; In addition, the heating element maintains the equilibrium temperature by controlling the electrical resistance even if the ambient temperature decreases or rises, the conductive coating layer for reducing the contact resistance generated between the conductor and the heating element, and the outer circumferential surface of the heating element is coated with polyolefin, fluorine resin It is used as it is or characterized by consisting of a jacket mixed with a polyolefin, fluororesin, flame retardant, inorganic filler, heat stabilizer or UV-stabilizer.

In order to achieve the above object, a method of manufacturing a self-regulating heater includes melting and kneading a resin mixture used in a heating element, a plastic spacer, and a jacket using equipment such as a short-bar mixer, a twin screw, an extruder, a boot kneader, and the like. A process of manufacturing in a state, coating a conductive coating layer on the surface of the conductor, and then using an extruder to make the same thickness as the conductor, the width of which is a sheet-shaped plastic spacer of about 5-l5mm according to the specification of the product. Forming a layer, coating the outer circumferential surface of the spacer and the conductor with a heating element, and finally covering the jacket by extrusion on the heating element, and heat treatment and electron beam to improve thermal stability separately from the above process. It is characterized in that it is made so as to pass through the irradiation process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the self-regulating heater is composed of a conductor 20, a conductive coating layer 22, a spacer 24, a heating element 26, and a jacket 28.

The conductive coating layer 22 uses a solution in which carbon black, graphite, etc. are dispersed in an olefin-based or fluorine-based resin or rubber in order to reduce the contact resistance generated between the conductor 20 and the heating element 26. ^It has a volume specific resistance of ³ · cm.

The heating element 26 is composed of a mixture of a crystalline resin, carbon black, an inorganic filler, an antioxidant (or a heat stabilizer), a crosslinking aid, and the like, and has an electrical conductivity of about 10 ³ -10 ⁴ Ω · cm. As a result, even if the ambient temperature rises above the equilibrium temperature, the carbon black conduction path of the heating element 26 is blocked by thermal expansion of the matrix resin, so that the heating element 26 no longer generates heat so that the heater is autonomously controlled. .

On the other hand, when the ambient temperature decreases and falls below the equilibrium temperature held by the heater, the resistance of the heating element 36 decreases, thereby increasing the amount of heat generated, thereby autonomously controlling the temperature.

The crystalline resin used for the heating element 26 may be polyolefin resin or polyvinyl such as low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene vinyl acetate, ethylene ethyl acrylate, ethylene methyl acrylate, and the like. Fluorine resins, such as lidene prolide, fluorinated ethylene propylene, ethylene tetra fluoroethylene, perfluoro alkyl vinyl ether, are used.

Furnace black or acetylene black is used as the carbon black used for the heating element 26.

The spacer 24 used for the heating element 26 uses a crystalline resin or a mixture of carbon black, an inorganic filler, a glass fiber reinforcing agent, an antioxidant, and the like, in the crystalline resin.

In addition, the crystalline resin used for the spacer 24 uses a material having a thermal expansion coefficient (linear expansion coefficient) of at least 10% or higher than that of the resin used for the heating element 26, so that the heating element 26 has a conductor 20. ) Can increase the PTC strength of the heating element 26 by increasing the expansion in the longitudinal direction.

The manufacturing process of this invention is as follows.

First, the resin mixture used for the heating element B6, the plastic spacer 24, and the jacket 28 is melt-trained using equipment such as a short-bar mixer, twin screw, extruder, booth kneader, and then manufactured in a chip state.

The conductive coating layer 22 is coated on the surface of the conductor 20.

Then, using an extruder, as shown in FIG. 3, the sheet 20 is made to have the same thickness as that of the conductor 20, and the width thereof is 5-l5mm, depending on the specification of the product.

The heating element 26 is coated while surrounding the outer circumferential surfaces of the spacer 24 and the conductor 20.

The jacket 28 is also coated on the heating element 26 as extrusion.

In addition, heat treatment and electron beam irradiation may be performed to improve thermal stability.

And when comparing the PTC strength (resistance change by temperature) and switching characteristics (output change by temperature) of the Examples and Comparative Examples of the present invention are shown in Table 1 below.

As described above, the self-regulating heater according to the present invention and the manufacturing method thereof improve the PTC characteristics of the heater by making the thermal expansion of the polymer matrix and the thermal expansion of the spacer complex to increase the spacing between particles, and the ambient temperature is equal to or higher than the equilibrium temperature or The present invention relates to a self-regulating heater and a method of manufacturing the same, which can eliminate the risk of explosion by controlling the same even if fluctuated below.

Claims (6)

By controlling electric resistance, spacers for reducing contact resistance by mixing carbon black, inorganic filler, glass fiber reinforcing agent or antioxidant with crystalline resin or crystalline resin, and controlling electric resistance even if the ambient temperature decreases or rises. A heating element that maintains an equilibrium temperature, a conductive coating layer for reducing contact resistance generated between the conductor and the heating element, and a coating on the outer circumferential surface of the heating element and using polyolefin or fluorine resin as it is, or flame retardant or inorganic filler in polyolefin or fluorine resin. , A self-regulating heater comprising a jacket in which a heat stabilizer or UV-stabilizer is mixed. The autonomous heater of claim 1, wherein the spacer has a thermal expansion coefficient (linear expansion coefficient) of at least 10% or more than the resin used for the heating element. The method of claim 1, wherein the conductive coating layer is composed of a mixture of carbon black or graphite, such as olefin-based, fluorine-based resin or rubber dispersed in a self-controlling heater having a volume intrinsic resistance of 10-10 ³ Ω · cm . According to claim 1, wherein the heating element is composed of a mixture of crystalline resin, carbon black, inorganic filler, antioxidant (or thermal stabilizer), crosslinking aid, etc., electrical conductivity of about 10 ³ -10 ⁴ Ω · cm Autonomously controlled heater characterized in that it has a. The polycrystalline resin of claim 4, wherein the crystalline resin includes low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene vinyl acetate, ethylene ethyl acrylate, ethylene methyl acrylate, and the like. A self-regulating heater comprising: fluorine resins such as lide, fluorinated ethylene propylene, ethylene tetrafluoroethylene, perfluoro alkyl vinyl ether, and the carbon black comprises furnace black or acetylene black. The resin mixture used for the heating element, the plastic spacer and the jacket is melt-kneaded using equipment such as a short-variety mixer, twin screw, extruder, booth kneader, etc., and then produced in a chip state, and a conductive coating layer is coated on the surface of the conductor. Forming a sheet-shaped plastic spacer of about 5-l5mm according to the specification of the product, and then covering the spacer and the outer circumferential surface of the conductor with a heating element. And finally, coating the jacket by extrusion on the heating element. The autonomous heater is characterized in that the heat treatment and electron beam irradiation may be carried out separately to improve thermal stability. Manufacturing method.