JPS60235386A - Flexible heating wire - 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 Industrial Application The present invention relates to a flexible heating wire used as a heater for electric blankets, electric carpets, etc., and as a wire for preventing excessive temperature rise.

Conventional Structure and Problems Conventionally, flexible heating wires used in electric carpets, electric blankets, etc. have a first conductor wire 1 and a second conductor wire 2 concentrically arranged as shown in FIG. The sharp melting behavior at the melting point of the nylon resin 3 interposed between the internal and external spirals was fully utilized to short-circuit both conductor wires and detect excessive temperature rise. However, with this structure, the winding process, which is low in productivity, must be performed twice: inner winding and outer winding, which limits productivity and cost.

On the other hand, the conventional heating wire with a positive temperature coefficient of resistance (hereinafter P
The TC heating line (referred to as TC heating line) was constructed as shown in FIGS. 1 and 2, for example. In Figures 1 and 2, 3 is PTC
It is a heat generating layer, and a pair of first and second conductor wires 2, 2' are spirally wound around its outer surface in FIG. 2 on the inside and outside in FIG. It is tubed with 5. A core yarn 4 is arranged on the inner surface of the twisted PTC heat generating layer 3. In this configuration, P of the PTC heat generating layer 3 is
It is possible to set a certain self-controlled temperature using the PTC curve of the TC heating layer 3, but due to external suppression, bending, twisting, etc., the distance between the electrodes may become locally small, and the PTC
If a conductive substance is mistakenly mixed into a part of the silent layer 3, the resistance value of the entire heating wire will hardly change, and the current will concentrate in that part, causing local overheating, arcing, and even a short between the electrodes. This caused burns, flames, and other safety hazards. As for the seat between the first and second conductor wires 1 and 2, there is a large change in the current value flowing through the entire heating wire, so it is difficult to completely stop the flow through the turbidity using a current fuse etc., although it is dangerous. As shown, the resistance value of the entire heating wire almost changes, but even if it changes, it is within the self-controlled resistance value range of the PTC heating wire itself, and safety cannot be ensured if N is concentrated in that local area. Purpose of the Invention The purpose of the invention is to solve the above-mentioned conventional problems, and to provide a product that is safe and highly reliable.

Composition of the Invention The non-invention is that the first conductor wire 1a and the second isoconductor wire 2a are formed parallel to each other in a spiral shape as shown in FIG. 3 on a heat-shrinkable core yarn 4a. It is characterized by The above-mentioned shrinkable core thread 4a means that the operating temperature of the overtemperature rise prevention device is 12
An insulating fiber that causes a large temperature change at temperatures between 0 and 200°C. Specifically, organic fibers such as polyester, polyamide, and polyvinyl alcohol copolymer (vinyl alcohol copolymer) are suitable, and this property is particularly noticeable in drawn yarns.

In addition, since the flexible heating wire of the present invention is manufactured with some tension applied during the wire manufacturing process, the flexible heating wire is stretched under the tension of the core yarn 4a. becomes. Therefore,
The heat-shrinkable core thread 4a in the present invention includes not only a thread that simply shrinks by heat, but also a thread that has a high elongation under a tension of about 0 to 5 kg. That is, this thread becomes an electric wire as it is stretched during the wire manufacturing process, and at an excessively elevated temperature of 120 to 200'C, stress is applied due to the softening of the outer sheath 5, causing it to shrink as an electric wire. The result is that Therefore, the heat setting treatment generally performed on the core yarn is a process of adjusting the ratio of elongation and heat shrinkability, and the heat shrinkability in the present invention is proportional to the sum of the elongation and heat shrinkage rate. That is, the flexible heating wire in the present invention shrinks significantly, for example, by 8% or more when the temperature rises abnormally, and the conductor wire 1 of both sides
There is a short circuit between poles a and 2a. The shrinkage rate at this time is approximately the sum of the heat shrinkage rate of the core yarn itself and the elongation during production of the heating wire.

The following two types of PTC heat generating layers 3 are used in the present invention. That is, in the case of a 118A line in which either the first conductor wire 1a or the second conductor wire 2a is used as a heat-generating wire and the other is used as a signal wire, the PTC heat-generating layer 3 is not necessarily necessary. A layer of hot melt polymer such as nylon 11.12 may also be provided. In this case, when the temperature rises abnormally, this layer 3 melts and changes into a low viscosity liquid, so that the safety operation of the present invention can be operated very stably.

(B) A PTC heating layer having a large positive temperature coefficient of resistance may be provided in the PTC heating layer 3, and in this case, the flexible heating wire of the present invention becomes a PTC heating wire that functions to prevent excessive temperature rise. .

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

[Example 1] A copper wire with a diameter of 0.17# and a thickness of 0.0 is placed on a heat-shrinkable core thread 4a of 1500 denier made of stretched nylon 6.
Make a 6m piece of foil, wrap two pieces in parallel with pitches of 1 and 2, and wrap the first piece of foil in parallel. The second conductor wires 1a and 2a were used. On top of that is a 0.5 m layer of soft polyvinyl chloride composition as an insulating jacket 5.
coated thick. This was designated as sample [A]. Separately, as sample [B], nylon 1 was prepared as shown in Figure 3.
After completely forming the PTC-derived layer 3 consisting of 2, the sample [
The insulating jacket 5 similar to A,] was coated. These samples [:A, B]k were set in a furnace, and a current of 0.8 was passed through the conductor wire 1a to generate heat, and the furnace was heated at a rate of 1°C/min. 1. second conductor wire 1a,
2a is sample [:A, 176°C sample C
B,] short-circuited at 169°C and fused the fuse,
A safe operation was performed to cut off the power. Compared to sample ['A],
[B] had less variation in operating temperature and was more stable in operation.

[Example 2] Stretched polyester core yarn 1 with 15oO denier
A, the first copper wire with the same specifications as [Example 1]. Second
The conductor wires 1a and 2a are wound around each other as a PTC heating layer 3.
A flexible heating wire as shown in FIG. 3 was constructed by covering the wire with 20% carbon blank, 30% polyethylene-vinyl acetate copolymer, and 50% polyethylene. When this was set in a furnace and heated at 1°C/min, it reached 172°.
1st in C. A short circuit occurred between the second conductor wires 1a and 2a, and a safety operation was performed in which the fuse was blown and the current was cut off.

In this way, sufficient safety can be ensured even against localized abnormal overheating. That is, the first and second conductor wires 1a and 2a are locally damaged due to external oppression, bending, twisting, etc.
The distance between the PTC heat generating layers 3 may be small, a conductive substance may be mixed into the PTC heat generating layer 3, or the first. When the second conductor wire 1a + 2a itself breaks or is about to break and local overheating occurs, the core thread 4ak
Heat shrink, 1st. The second conductor wires 1a and 2a are contacted and short-circuited, and the first conductor wires 1a and 2a are contacted and short-circuited. Second conductor wires 1a, 2a'ft: These are used as sheets to melt a current fuse and cut off current to detect abnormal overheating or local overheating. This flexible heating wire has a simple configuration as shown in FIG. 3, has PTC characteristics and an overheat fusing function, and is a highly safe and highly functional flexible heating wire.

Note that the heat-shrinkable core thread 4a exhibits a shrinkage rate of 8% or more at 120'C to 200°C.
C indicates the safe operating temperature at the time of abnormal temperature rise, and a shrinkage rate of 8% or more indicates the shrinkage limit for reliable safe operation. The melting point of the core thread 4a is 200°C.
The following is based on the following reasons. That is, when installed in a fabric electric heating device,
If the temperature rises above 200°C, it will catch fire and smoke, causing an accident. Therefore, it is important for product safety to have an overrise prevention temperature of 200°C or less. Also PTC
The heat generating layer 3 is a polymer composition containing a particulate conductive agent mainly composed of carbon black, and examples of the resin used therefor include polyethylene-vinyl acetate copolymer, polyethylene-ethyl acrylate copolymer, polyethylene, There are crystalline resins such as polyolefins such as polypropylene, polyamides, and polyesters, which exhibit a sharp positive temperature coefficient near the crystal transformation point of 60 to 180°C.

1st. The distance between the second conductor wires 1a + 2a is 0.3
The PTC heating layer 3 may be made of a composition having a 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.

Due to external pressure, bending, twisting, etc., the first.
If the distance between the second conductor lines becomes small, or if a conductive substance is mixed into the PTC heating layer, or if the first Local overheating that occurs when the second conductor wire itself is disconnected or about to disconnect, or is heated abnormally due to external factors, etc.
When abnormal overheating or even overheating due to arcing occurs, the core yarn contracts, causing the first. The second conductor wire is short-circuited, the current fuse is blown, the current supply is stopped, and safety can be improved.

[Brief explanation of the drawing]

FIG. 3 is a side view showing an embodiment of the present invention. 1a, 2a-゛-first, second conductor wire, 3-=-P T
C heating layer, 4a...core wire.

Claims (5)

[Claims] (1) A first conductor wire and a second conductor wire are spirally wound in parallel on a core yarn, and when the temperature rises abnormally, the first conductor wire and the second conductor wire are Flexible heating wire that shorts the wire. (2) The flexible heating wire according to claim 1, wherein the core yarn shrinks by 8% or more during abnormal JA-lag. (3) The flexible heating wire according to claim 1 or 2, wherein the core yarn is one selected from polyester, polyamide, and polyvinyl alcohol copolymers. (4) The flexible heating wire according to claim 1 or 2, wherein one of the first and second conductor wires is a heating wire and the other is a signal wire. (5) PTC heat generation using a composition that is thick and has a positive temperature coefficient of resistance (hereinafter abbreviated as PTC) at a temperature lower than the heat shrinkage temperature of the core yarn on the first and second conductor wires formed in a spiral shape. A third conductor wire is formed in a spiral shape on the outer side of the layer, and one of the first and second conductor wires and the third conductor wire are used as electrodes of the PTC heating layer. The flexible heating wire according to item 1. (6) The flexible heating wire according to claim 5, wherein the PTC heating layer is made of a polyolefin composition containing carbon black.