JPS6089089A - Flexible 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 Field of the Invention The present invention relates to the structure of a flexible heating element used in heating appliances and the like.

Conventional construction and problems thereof A conventional heating wire having a positive temperature coefficient of resistance (hereinafter referred to as a PTC heating element) was constructed as shown in FIGS. 1 and 2, for example. 1 and 2, 1 is a PTC heating layer, and a pair of electrodes 2 and 2 are spirally wound around its outer surface in FIG. 1 and inside and outside in FIG. The outer surface is tubed with an insulator 3.

Further, a core thread 4 is arranged on the inner surface of the PTC heat generating layer.

In this configuration, a certain self-control temperature can be set using the PTC curve of the PTC heat generating layer 1, but the distance between the electrodes may become locally small due to external pressure, bending, twisting, etc. - If a conductive substance is mistakenly mixed in the PTC heating wire, the resistance value of the entire PTC heating wire will almost change, and the current will concentrate in that part, causing local overheating, arcing, and even a short between the electrodes, resulting in burns. However, there were aspects that could impair safety, such as flames. Regarding a short circuit between the electrodes 2 and 2, there is a large change in the current value flowing through the entire PTC heating wire, so it is possible to easily stop the current flow using a current fuse, etc., although it is dangerous, but as mentioned above,
Fortunately, the resistance value of the entire PTC heating wire does not change, and even if it changes, it is within the self-control resistance value range of the PTC heating wire itself.
Safety cannot be ensured if the current is concentrated in that local area.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems and aims to provide a safe and highly reliable device.

Structure of the Invention In order to achieve the above object, the flexible heating wire of the present invention is made of PT
At least one pair of electrodes is provided on a core thread having a melting point higher than the self-controlled temperature of the C heat generating layer, and a PTC heat generating layer is provided on the outside thereof.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, reference numeral 1 denotes a PTC heating layer, in which a pair of electrodes 2a and 2b are spirally wound around a core yarn 4 having a melting point of 200° C. or less.

A PTC heat generating layer 1 is disposed in contact with the core thread 4 and the electrodes 2a, 2b, and the outside thereof is covered with an insulating jacket 3.

With the above configuration, sufficient safety can be ensured even against localized abnormal overheating. That is, the distance between the electrodes 2a and 2b may be locally reduced due to external pressure, bending, twisting, etc., a conductive substance may be mixed into the PTC heat generating layer 1, or the i-electrode 2a, 2b may be When local overheating occurs due to wire breakage or almost breakage, the core thread 4 is melted and the electrodes 2a and 2b are
with the electrodes 2a and 2b in contact with each other and the current 5'i is applied as a sheet.
” It blows the fuse and detects abnormal overheating and local overheating.This PTC heating wire has PTC characteristics and overheating blowing function in a simple configuration as shown in Figure 3.
It is a flexible heating wire with high safety and high @ability. As the core thread 4 having a melting point above the self-control temperature of the PTC heating layer and below 200°C, either twisted thread or convergent thread can be used, and the material is a crystalline material selected from polyamide, polyvarnish, and polyolefin. Polymers are suitable. This is 20
This is because it has a melting point below 0° C., is crystalline, has a low melt viscosity, and has excellent temperature fuse performance. Among them, -NH(CH2)lρ0-NH(CH2)1, which is the monomer unit of nylon 11 and nylon 12.
A polymer containing 1 CO- is suitable, and nylon 11 and nylon 12 threads can be used as the core thread 4. These core threads 4
If the tensile strength is insufficient, it is also possible to add a separate core thread. The reason why the core yarn 4 has a melting point of 200° C. or less is based on the following reason. That is, when installed in a fabric electric heating device, 2006
If the temperature rises above 100°F, it may ignite and emit smoke, causing an accident. Therefore, it is important for product safety to have an excessive rise prevention temperature of 200°C or less.

The PTC heating layer 1 is a polymer composition containing a particulate conductive agent mainly composed of carbon black. For example, resins used therein include polyethylene-vinyl acetate copolymer, polyethylene-ethyl acrylate copolymer, There are polyolefins such as polyethylene and polypropylene, and crystalline resins such as polyamide and polyester.
It shows a sharp positive temperature coefficient near the crystal transformation point of 80°C.

The distance between the pair of electrodes 2a and 2b is approximately 0.3 to 2 cuts, and the PTC heat generating layer 1 may be made of a composition with high specific resistance, and PTC characteristics for self-temperature control can be easily obtained.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

The distance between the electrodes may become locally small due to external pressure, bending, twisting, etc., the PTC source may contain conductive substances, the electrodes themselves may be disconnected or almost disconnected, or Local overheating, abnormal overheating that occurs due to abnormal heating due to external factors, and even overheating due to arcing can cause the core yarn to melt.
Current fuses can be blown to improve safety.

[Brief explanation of drawings]

1 and 2 are a perspective view and a side view showing a conventional example, and FIG. 3 is a side view showing an embodiment of the present invention. 1... PTC heat generating layer, 2. z...electrode, 3...
...Representative 1 patent attorney Toshio Nakao and 1 other famous confectionery
1 Figure 1'3 Figure 2 Figure 3

Claims (6)

[Claims] (1) P with a positive temperature coefficient of resistance (hereinafter abbreviated as PTC)
A flexible heating element comprising at least one pair of electrodes provided on an electrically insulating core wire having a melting point higher than the self-control temperature of the TC heating layer, and the PTC heating layer formed on the outside of the electrodes. (2) The flexible heating element according to claim 1, wherein the core wire is a twisted yarn or a convergent yarn. (3) Claim 1, wherein the core wire is a crystalline polymer selected from polyamide, polyester, and polyolefin.
Flexible heating element as described in Section 1. (4) Polyamide is a repeating unit -NH(CH2)1o
The flexible heating element according to claim 3, which is a polymer containing CO- or -NH(CH2)1□CO-. (5) The flexible heating element according to claim 1, wherein a pair of electrodes are spirally wound in parallel on a core wire. 2... (6) The flexible heating element according to claim 1, wherein the PTC heating layer is made of a carbon-containing polyolefin polymer.