KR20040091993A - Resin composition for electrically insulating, insulator produced therefrom, and temperature-set type detecting wire comprising the insulator - Google Patents

Abstract

PURPOSE: A resin composition is provided to be capable of producing an insulator for a fixed temperature type detecting wire, which has a short circuit at a predetermined temperature in a predetermined period by virtue of low heat-resistance and high electrical resistance value. CONSTITUTION: The resin composition for an insulator comprises (a) 60.0-65.0 wt% of ethylene vinyl acetate(EVA) copolymer and 10.0-18.0 wt% of linear low density polyethylene(LLDPE) resin as base resins, (b) 10.0-18.0 wt% of a filler, (c) 0.5-3.0 wt% of an antioxidant, (d) 2.5-5.0 wt% of wax, and (e) 0.1-2.0 wt% of pigments, each being based on total weight of the composition. The electrical insulator is manufactured by the method comprising mixing and pelletizing the above resin composition; inputting the composition into a material hopper; and then passing the composition through 1-5 zones sequentially under pressure. The fixed temperature type detecting wire(2) for 1- or 2-signals includes conducting wires(11), insulators(12), a PS tape(13) and a sheath(14).

Description

Resin composition for electrically insulating, insulator produced therefrom, and temperature-set type detecting wire comprising the insulator}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for electrical insulation, an insulator manufactured therefrom, and a product including the insulator, wherein the ethylene vinyl acetate copolymer (EVA) and linear low density polyethylene (LLDPE) resin are used as base resins. It relates to a resin composition for insulation, an insulator manufactured from the resin composition, and a constant temperature sensing wire produced by coating a conductor with the prepared insulator.

With the development of technology, the facilities of modern society, grouped and informed, are scattered above and below the ground. Compared to the existing ground installations, underground burial is buried underground without being exposed to the naked eye and is called 'underground tools'. Representative tools of this underground tool include electric power tools, communication tools, cavity tools, cable trays, chemical plants, gas tanks, dangerous goods storage, and transmission stations of media organizations. many. Therefore, there is an urgent need to develop a device for preventing these underground tools from fire in advance to prevent damage to property, damage to information, and the like.

Currently, various installation pipes such as power cables, water pipes, gas pipes, heating pipes, communication cables, etc. are piped and managed for different purposes by different organizations, and are installed and managed according to separate guidelines. have. For example, in a place where heating pipes and power cable pipes are installed at the same time, the competent authority is piped by heating and power works, and the monitoring temperature is set differently according to the characteristics of each tool.

It is a fire detection device attached to the ceiling or wall to detect fires in buildings, etc., and a constant-temperature fire detector that detects by a heat sensor and generates an electrical signal through a circuit to operate an alarm device. 20-0219919.

In addition, as a sensing device for underground tools, a sensing wire made of a steel wire having a twisted shape of two strands coated with a material having very low heat resistance and electrically insulating material is wound with a protective tape, and then coated with a flame retardant material and a constant current connected thereto. A constant temperature linear fire detection apparatus capable of determining an accurate firing point by digitizing a line short circuit between the sensing lines having a predetermined resistance value using a circuit is disclosed in Korean Utility Model Publication No. 20-0204673. The constant temperature sensing linear sensor is characterized by a fire heat sensing line that has the function of sensing the temperature of underground tools from the sensing line itself and transmitting it to the central monitoring and control center.

However, only the configuration of the detection system in the constant temperature detection linear fire detection device is disclosed, and the material for the insulating material, the protective tape, the flame retardant coating, or the manufacturing method thereof is not mentioned at all. In particular, the insulating material is described only as an electrically insulating material having a very small heat resistance and no mention of specific materials or insulating properties. In addition, since the conductive wire used as the sensing wire is made of only two strands of steel wire, the sensing wire manufactured therefrom is limited to one signal type in which a signal is generated by a single short circuit.

Insulators used for constant temperature sensing wires for underground tools must have characteristics that must be available and short-circuited at specific temperatures (eg 70 ° C, 90 ° C) within a certain time range. These insulators are components that determine the performance of the detector. to be.

Therefore, the material for use as an insulator must have low heat resistance, properties that are available within a certain time at a specific temperature, and have a predetermined insulating property (insulation resistance). In particular, the type approval and certification technique standards of the Fire Services Act must be satisfied.

The detection line of the conventional detector is often short-circuited with time, and its insulation resistance is low, and several months after installation, the product itself may cause a mixture or short circuit, resulting in a malfunction even though a fire does not occur. As a result, there is a difficulty in monitoring system, and enormous costs are added due to frequent replacement of products.

In this situation, there has been a steady need for stable insulators that can be used for constant temperature sensing wires.

Accordingly, the present inventors have made a lot of experiments to solve the above problems of the conventional insulators, and as a result, the heat resistance is weak in consideration of the special situation of the basement, is available within a specific time range at a specific temperature, the short circuit, insulation resistance We found a resin composition for electrical insulation for constant temperature detection wires that can check the short-circuit of the detection wires for a long time in advance, and obtain an insulator from them, and apply it to the constant temperature detection wires, which is much higher than the conventional constant temperature detection wires. Excellent products were made to complete the present invention.

Accordingly, an object of the present invention is to provide a resin composition for electrical insulation, which has low heat resistance, is soluble in a specific time range at a specific temperature, and has high insulation resistance.

Still another object of the present invention is to provide an insulator made of the resin composition for electrical insulation.

Still another object of the present invention is to provide a one- or two-signal constant temperature sensing wire including the PVC sheath having excellent durability and excellent heat transfer to the insulator, and an environmentally friendly polyurethane sheath.

1 is a view showing the structure of a constant temperature (70 ℃ or 90 ℃) detection line (2-wire) according to an embodiment of the present invention.

2 is a cross-sectional view of a constant temperature (70 ° C. or 90 ° C.) detection line (two wire type) according to an embodiment of the present invention.

3 is a diagram illustrating a structure of a constant temperature (70 ° C. and 90 ° C.) sensing line (3-wire) according to another embodiment of the present invention.

4 is a cross-sectional view of a constant temperature (70 ° C and 90 ° C) sensing line (3-wire) according to another embodiment of the present invention.

Brief description of the major symbols in the drawings

1: sense wire (2-wire), 2: sense wire (3-wire or 2-signal), 11: lead wire,

12: insulator, 13: PS tape, 14: sheath

The resin composition for electrical insulation of the present invention is characterized by comprising an ethylene vinyl acetate copolymer (EVA) and a linear low density polyethylene (LLDPE) resin as a base resin, and containing a filler, an antioxidant, a wax and a pigment.

Specifically, based on the total weight of the composition, EVA 60.0-65.0%, LLDPE 10.0-18.0%, filler 10.0-18.0%, antioxidant 0.5-3.0%, wax 2.5-5.0 and pigment 0.1-2.0% Resin compositions are preferred.

Particularly preferred is a resin composition for electrical insulation consisting of 62.5% EVA, 15.6% LLDPE, 15.6% filler, 1.6% antioxidant, 3.9% wax and 0.8% pigment, based on the total weight of the composition.

The additive component and content are determined within the content range in consideration of compatibility with the base resin, insulation, work stability, and the like.

The EVA resin used in the present invention is an ethylene and vinyl acetate copolymer resin, and has excellent transparency, flexibility, low temperature brittleness, ductility, and the like, and is used as a raw material resin for footwear materials, agricultural films, extrusion coatings, and the like.

In addition, it is possible to adjust the content of vinyl acetate (VA) in the EVA resin or increase or decrease the content of LLDPE in accordance with the temperature of the sensing object in the constant temperature sensing line (1, 2) to be described later. That is, as the detection temperature of the object increases, the content of vinyl acetate (VA) may be reduced within the above content range, or the content of the LLDPE in the base resin may be increased.

LLDPE used in the present invention is a resin excellent in mechanical properties and excellent in heat sealing and workability. In particular, the LLDPE used in the present invention is excellent in thermal stability, suitable for electric wire use, excellent mechanical strength and environmental stress cracking resistance.

Pigments that can be used in the present invention are used for coloring, and are excellent in heat resistance, weather resistance, and chemical resistance, and are classified into white, black, blue, red pigment, etc. according to coloring, and inorganic and organic pigments according to chemical components. In the invention, it is used variously according to the product (70 degreeC, 90 degreeC sensing line).

In addition, the present invention relates to an insulator 12 made of the composition, characterized in that it is produced by the following method.

After mixing the base resin EVA and LLDPE at a predetermined temperature, the filler, antioxidant, wax and pigment are mixed and pelletized, and then put into a raw material hopper. Then, it is extruded by sequentially passing 1 to 5 zones (Zone) by pressing the pressure of the extruder screw.

At this time, the mixing temperature of EVA and LLDPE is preferably 110 ~ 130 ℃. When the extruder heat distribution is divided into five zones, the set temperatures of 1 to 5 zones are respectively 155 ° C ± 5 ° C, 165 ° C ± 5 ° C, 170 ° C ± 5 ° C, 155 ° C ± 5 ° C, and 150 ° C ± 5 ° C. It is preferably in the range, wherein the working ship speed is about 850 RPM. The surface shape of the final extruded insulator 12 is preferably somewhat rough, such as bubble phenomenon.

The present invention also relates to a constant temperature sensing line (1, 2) comprising the prepared insulator (12).

Constant temperature detection line (1, 2) is a conductor (11) for transmitting a fire occurrence signal is shorted by the availability of the insulator 12 when the sensing object rises to a specific temperature;

An insulator (12) that insulates the strands (11) strands but is available at a specific temperature to short the strands of the conductors (11);

PS tape (13) for associating the insulator (12);

Sheath 14 for jacketing the PS tape 13

It refers to a cable which is configured to be short-circuited between the conductors 11 by the availability of the insulator 12 in the event of a fire, and transmits a signal to the monitoring control headquarters so that real-time monitoring is possible.

The conductive wire 11 is selected to have a weak tensile strength due to the characteristics of the underground tool that must operate very sensitively, specifically, a galvanized steel wire, wherein the zinc content is 80 to 150 g / m ² and the carbon content is 0.65 to 1.25. The weight percent and tensile strength is preferably 0.7 to 0.9 mm in diameter within the range of 160 to 210 kg / km ² , and nickel chrome wire or stainless steel wire may be used. The number of the conductors 11 may be two (one signal type) or three (two signal type) depending on the wire type.

As described above, the insulator 12 is available at a specific temperature while surrounding the conductor 11 to serve to short-circuit the conductor 11. The insulation thickness varies depending on the sensing temperature (nominal operating temperature), and is usually in the range of 0.18 to 0.30 mm for the 70 ° C sensing line (1), 0.20 to 0.35mm for the 90 ° C sensing line (1), and two signal sensing lines (2). ) Is adjusted within the range of 0.18 to 0.30 mm (1 wire) and 0.20 to 0.35 (2 wire) mm.

The PS tape 13 is for preventing separation of the insulation-coated conductor 11 and preventing the insulator 12 from melting and shorting in a sheath process described later. Combine conductors 11 within the range of 36 to 51 mm for sensing line 1, 39 to 60 mm for 90 ° C sensing line 1, and 45 to 102 mm for two-signal (three-wire) sensing line 2. Depending on the specificity of the underground tool, the pitch length may change somewhat. Normally, 1/3 overlap is used for 20mm (width) × 0.015mm (thickness), but the width and thickness of PS tape 13 can be changed according to the specificity of underground tools. 2 Pitch methods such as overlapping are various, and the width can be changed according to the characteristics of underground tools. Winder tension is very important when pitching, so it is important that the insulation breaks and shorts or crosses if the operator does not adjust the tension depending on the characteristics of each machine.

The sheath 14 may be made of polyvinyl chloride (PVC) or polyurethane, which transmits temperature to the insulator 12, prevents damage due to contact with each other and underground facilities, and is selected for durability. do. The thickness of the sheath 14 ranges from 0.45 to 0.60 mm for the 70 ° C. sensing line 1, 0.50 to 0.65 mm for the 90 ° C. sensing line 1 and 0.55 to 0.75 mm for the two signal sensing line 2. Care must be taken not to rupture the insulation inside.

As used herein, the "two-signal (three-wire) sensing line (2)" is selected separately for the sensing line (1) for 70 ℃, 90 ℃ according to the temperature prediction of the underground tool when laying underground tools, Underground tools are installed differently according to the supervising departments, and they are complex sensing lines that can sense and transmit 70 ℃ and 90 ℃ at the same time when their prescribed temperature is different and can be used completely different from the original underground tool design. The two-signal (three-wire) sensing line 2 is designed for different insulation thicknesses for 70 占 폚 and 90 占 폚. That is, when the temperature rises to 70 ° C., two wires are short-circuited and a signal is generated. If the temperature rises further to 90 ° C., the short-circuit two wires and the other unshorted one wire are short-circuited to generate a signal. Will work twice.

In the description of the sheath process, the fed pitch fed by the feeding of the feeder is coated with extruded PVC or polyurethane material to form a cable shape, and the cable-shaped extruded material is discharged through a die, and then Cooling is carried out through a cooling bath while being drawn out to produce the constant temperature detection lines (1, 2) of the present invention.

Evaluation / inspection of the final manufactured thermostatic sensing lines 1 and 2 was tested according to the fire method.

In the current method, the insulation resistance is 1,000㏁ in 1m, but if the insulation resistance is lower or similar, it may malfunction even though there is no fire because the product itself is mixed or disconnected within a few months after installation and use. have.

In the present invention, the thickness or length of each component of the sensing lines 1 and 2 is changed in accordance with the temperature change (nominal operating temperature) of the sensing object.

The thickness or length of each configuration by sensing temperature is as follows:

70 ° C sensing wire (1): insulation thickness (2 wires) 0.18 to 0.30 mm,

PS tape 13 (pitch length) 36-51mm,

Sheath 14 0.45-0.60 mm thick.

90 ° C detection wire (1): 0.20 to 0.35 mm insulated thickness (2 wires)

PS tape 13 (pitch length) 39-60mm,

Sheath 14 0.50-0.65 mm thick.

Two-signal sensing wire (2): 0.18 to 0.30 mm in insulation thickness (1 wire)

Insulation thickness (2-wire) 0.20 to 0.35 mm,

PS tape 13 (pitch length) 45-102mm,

Sheath 14 thickness 0.55-0.75 mm.

More specifically,

70 ° C sensing wire (1): 0.25 mm of insulation thickness (2 wires)

PS tape 13 (pitch length) 45mm,

Sheath 14 thickness 0.50 mm.

90 ° C sensing wire (1): 0.30mm insulation thickness (2 wires)

PS tape 13 (pitch length) 50mm,

Sheath 14 thickness 0.60 mm.

2-signal sensing wire (2): 0.25mm insulation thickness (1 wire),

Insulation thickness (2-wire) 0.30mm,

PS tape (13) (pitch length) 80mm,

Sheath 14 thickness 0.65 mm.

However, the nominal operating temperature is not limited to 70 ° C., 90 ° C., and can be arbitrarily changed by those skilled in the art according to the insulator 12 thickness, pitch length, sheath 14 thickness, and the like.

In addition, the constant temperature sensing wires 1 and 2 including the insulator 12 according to the present invention are provided with two (two wires) to three (three wires) wire conductors 11 according to the wire type (a wire step). ) → a process of insulating coating the conductors 11 using the insulator 12 (insulation process) → a process of associating the insulation coated conductors 11 in a braided form (association process) → while extruding the sheath 14 It is characterized by being manufactured through a process (sheath process) of covering the union pitch and jacketing. In the drawing process, the conductive wire 11 may be a zinc steel wire, nickel chrome wire, or a stainless steel wire. In this case, care should be taken not to discolor the steel wire at room temperature.

If the final manufactured constant temperature sensing lines 1 and 2 are installed in underground tools, special pipes, etc., when the temperature rises above a certain temperature due to an abnormality or sudden short circuit of each facility, the insulator 12 melts and is monitored. The conductors 11 electrically connected to the control station such as the headquarters are shorted to each other to transmit a fire occurrence signal. Therefore, the control station can grasp the short-circuit state of the conductor 11 in real time to prevent the occurrence of fire in advance.

On the other hand, the installation of the constant temperature detection line (1, 2) according to the present invention is to install the constant temperature detection line (1, 2) on the pipe or between the pipes in an S-shape, which is a characteristic of each installed in various underground tools This is to protect the pipe products with the widest detection range and protect them from fire at the same time.

The constant temperature detection lines 1 and 2 of the present invention are not necessarily limited to use only for underground tools or special pipes, and can be used everywhere in other buildings and homes.

In addition, the constant temperature detection line (1, 2) of the present invention, if the detection line of some section is damaged by fire, etc., only the damaged portion can be replaced after disposal.

In addition to the insulator 12 and the constant temperature detection line (1, 2) of the present invention described above, it is apparent to those skilled in the art that various modifications or changes can be made without departing from the scope of the present invention. Thus, such variations or modifications are of course within the scope of the claims.

Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to these Examples.

Example

Example 1 Fabrication of Insulator 12

Extrusion temperature and manufacturing conditions for each part of the extruder used to manufacture the insulator 12 of the present invention are as follows.

Extruder heat distribution

Zone 1: 155 ℃, Zone 2: 165 ℃, Zone 3: 170 ℃, Zone 4: 155 ℃, Zone 5: 150 ℃

Working speed 850RPM.

The part temperature was controlled by an automatic temperature control system.

After mixing 6.25 kg of EVA (Prefectural Petrochemical, EF 443), which is a base resin, and LLDPE (Aekyung Emulsifier, 1.56 kg at 120 ° C), 1.56 kg of filler (manufactured by Hanwha Chemical), antioxidant (made by Cheil Chemical) , 390 g of wax (manufactured by Daegu Industrial Co., Ltd.) and 80 g of pigment (manufactured by Daeguk Industry Co., Ltd.) were mixed and pelletized, and then charged into a raw material hopper, and then sequentially passed through 1 to 5 zones by pressurization under the pressure of an extruder screw. To obtain an insulator 12 having a bubble-shaped rough surface.

Preparation Example 1 Fabrication of PVC Sheath 14

Extrusion temperature and manufacturing conditions of each part of the extruder (single screw type) are as follows.

Cylinder 1 #: 160 ℃ ± 2 ℃,

Cylinder 2 #: 160 ℃ ± 2 ℃,

Cylinder 3 #: 150 ℃ ± 2 ℃,

Cylinder 4 #: 155 ℃ ± 2 ℃,

Cylinder 5 #: 150 ℃ ± 2 ℃,

Head 1 #: 150 ℃ ± 2 ℃,

Dice 1 #: 155 ° C ± 2 ° C,

Screw RPM 900,

Rostanj RPM 800,

Coolant temperature 20 ℃

Die-Cooling Tank Distance 5-10cm.

Components and contents for producing the PVC sheath 14 are as follows.

ingredient Content (parts by weight)

PVC resin 100

Polyester Elastomer (PSE (TL) 30

Diisodecyl Phthalate (DIDP) 40

Lead (Ⅲ) 1 Anhydride 6

Lead (II) Stearate 0.4

Barium Stearate 1

Stearate 0.4

Calcium Carbonate 10

Antimony oxide 5

Tetrabromo bisphenol A (TBBA) 2

Titanium Oxide 0.8

White Pigment (MDAC) 0.02

The ingredients were combined at once and then mixed four times to cut into pellets. Subsequently, after supplying five cylinders sequentially through the single screw screw extruder of the specification, it was quenched in a 20 ° C cooling water tank 5-10 cm away from the die to remove all residual heat to produce a PVC sheath. At this time, the reason why the temperature of the cylinder # 5 is small is to prevent the short circuit of the insulator 12 manufactured in Example 1 during the sheath process.

In the manufacturing process of the polyurethane sheath 14, the extrusion temperature condition of each part of the extruder (single screw type) is 20 to 40 ° higher than that of the PVC sheath.

Example 2 Preparation of Constant Temperature (70 ° C) Sensing Line 1

First, two galvanized steel wires, nickel chrome wires, or stainless steel wires having a diameter of 0.8 mm were insulated and coated with a thickness of 0.25 mm with the insulator 12 prepared in Example 1, respectively. In order to prevent the detachment of the insulation-coated conductor 11, 1/3 was overlapped with the combined pitch length 45mm. The PVC sheath 14 prepared in Preparation Example 1 thereon was jacketed to a thickness of 0.50 mm to prepare a 70 ° C. sensing line 1.

Example 3: Preparation of the constant temperature (90 degreeC) sensing line 1

In Example 2, except that the insulation thickness was 0.30 mm, the combined pitch length was overlapped 1/3 by 50 mm, and the PVC sheath 14 prepared in Preparation Example 1 was jacketed to a thickness of 0.60 mm. 90 degreeC sensing line 1 was manufactured by carrying out similarly to the process.

Example 4 Preparation of Constant Temperature Three-Wire (70 ° C. and 90 ° C.) Sense Line 2

The galvanized steel wire or nickel chrome wire or stainless steel wire is three instead of two, the insulation thickness is 0.25mm (1 wire), 0.30mm (2 wire), and the combined pitch length is 80mm 1/3 overlapping. Except that the PVC sheath prepared in Preparation Example 1 was jacketed to a thickness of 0.65mm, it was carried out in the same manner as in the manufacturing process of Example 2 to prepare a three-wire sensing line (2).

Test Example

Test Example 1: Measurement of Nominal Operating Time

The sensing line 1 manufactured in Examples 2 and 3 was subjected to the operation test and the non-operation test according to the test criteria defined in the Type Approval and Validation Technical Standards of Fire Protection Sensors.

The test method is as follows:

(A) Operational test

Measure the operating time by inserting the detector into a vertical airflow with a temperature of 125% of the nominal operating temperature and a wind speed of 1m / s.

It shall operate within the time specified by the following formula.

T = [t ₀ Log ₁₀ {1+ (θ-θ _r ) / δ}] / [Log ₁₀ {1+ (θ / δ)}]

Where T is the operating time, t ₀ is the operating time (seconds) when the room temperature is 0 ° C, θ is the nominal operating temperature (° C), θ _r is the room temperature (° C), and δ is the nominal operating temperature and operation test The difference with temperature is shown.

(B) Non-operational test

Check the operation by inserting the detector into a vertical airflow at 10 ℃ lower than the nominal operating temperature and having a wind speed of 1m / s. It should not work within 10 minutes.

In the above formula, the reference operating time for the constant temperature sensor should be in the range of 32.4 to 97.3 seconds for the 70 ° C sensor and 34.3 to 103 seconds for the 1 type at room temperature (23 ° C).

Test result

Sixteen test samples of 70 ° C. (1) and eight test specimens (1) of 90 ° C. according to the present invention were manufactured to measure a reference operating time. The results are shown in the table below.

1) 70 ℃ detection line (1) (room temperature: 23 ℃)

Classification Test Body Base operating time in seconds Operational test (seconds) Non-operational test One 32 to 97 seconds 96 Floating action 2 84 Floating action 3 86 Floating action 4 93 Floating action 5 81 Floating action 6 80 Floating action 7 77 Floating action 8 80 Floating action 9 71 Floating action 10 64 Floating action 11 65 Floating action 12 70 Floating action 13 72 Floating action 14 62 Floating action 15 72 Floating action 16 69 Floating action

2) 90 ℃ detection line (1) (23 ℃ at room temperature)

Classification Test Body Base operating time in seconds Operational test (seconds) Non-operational test One 34-103 97 Floating action 2 88 Floating action 3 93 Floating action 4 83 Floating action 5 62 Floating action 6 96 Floating action 7 92 Floating action 8 67 Floating action

As can be seen from the above tables, the constant temperature sensing line 1 according to the present invention satisfies the reference operating time defined by the fire method at 70 ° C. and 90 ° C., respectively, and was satisfactory in the sensitivity test such as a non-operation test.

Insulation resistance measurement

Fire protection provisions for constant temperature detectors The insulation resistance shall be at least 1,000 kΩ per meter.

The value measured with the 500 volt DC insulation resistance meter using the constant temperature detection wire 1 manufactured in the said Examples 2 and 3 was 1,000 m or more to 1-2000m.

As described above, the insulator 12 according to the present invention satisfies the property of being available and short-circuited within a specific time range at a specific temperature. Accordingly, the constant temperature detection lines 1 and 2 including the insulator 12 have a case where the detection line of the conventional detector has a low insulation resistance and malfunctions due to a natural short-circuit as time passes, thereby causing a fire alarm. It can prevent and greatly reduce the cost of product replacement.

In addition, it satisfies the insulation resistance value and standard operating time specified in the relevant laws and regulations, so that the short-circuit of the sensing line can be checked stably, preventing the development of large fires in advance, and managing the sensing object more systematically. have.

In addition, it is possible to adjust the bow of the conductor 11, the thickness of the insulator 12, the pitch length of the PS tape 13, and the thickness of the PVC sheath 14 to be designed to react to a specific time at a specific time. Sensors can be manufactured.

Claims (12)

(a) a base resin for electrical insulation comprising ethylene vinyl acetate copolymer (EVA) and linear low density polyethylene (LLDPE) resin, (b) filler, (c) antioxidant, (d) wax and (e) pigment Resin composition. The method according to claim 1, comprising 60.0 to 65.0% EVA, 10.0 to 18.0% LLDPE, 10.0 to 18.0% filler, 0.5 to 3.0% antioxidant, 2.5 to 5.0 wax, and 0.1 to 2.0% pigment. Resin composition for electrical insulation characterized by the above-mentioned. The resin composition for electrical insulation according to claim 2, comprising 62.5% EVA, 15.6% LLDPE, 15.6% filler, 1.6% antioxidant, 3.9% wax and 0.8% pigment based on the total weight of the composition. An insulator prepared by mixing the resin composition for electrical insulation according to claim 1, pelletizing it, putting it in a raw material hopper, and pressing it under pressure of an extruder screw to sequentially pass 1 to 5 zones. The method of claim 4, wherein the set temperatures of the 1 to 5 zones are in the range of 155 ° C ± 5 ° C, 165 ° C ± 5 ° C, 170 ° C ± 5 ° C, 155 ° C ± 5 ° C, 150 ° C ± 5 ° C Insulator made. A conducting wire which is shorted by the availability of an insulator when the sensing object rises to a specific temperature and transmits a fire occurrence signal; An insulator that insulates the conductor strands and is soluble at a specific temperature to short the conductor strands; A PS tape for associating the insulator; A constant temperature sensing line composed of polyvinyl chloride (PVC) or polyurethane sheath jacketing the PS tape, the constant temperature sensing line comprising the insulator according to claim 4. 7. The wire according to claim 6, wherein the conductive wire is composed of two or three wires of 0.7 to 0.9 mm in diameter within the range of 80 to 150 g / m ² zinc, 0.65 to 1.25 wt% carbon, and 160 to 210 kg / km ² tensile strength. Constant temperature sensing line, characterized in that configured. 7. The PVC sheath according to claim 6, wherein the PVC sheath is pelletized by mixing PVC, a polyester elastomer, a heat stabilizer, a filler, a plasticizer, and a pigment, and then fed into an extruder, passing five cylinders sequentially, and then cooling water A constant temperature sensing line, characterized in that it is manufactured by quenching in a bath. The temperature of cylinders 1 to 5 of the extruder is set to 160 ° C ± 2 ° C, 160 ° C ± 2 ° C, 150 ° C ± 2 ° C, 155 ° C ± 2 ° C, 150 ° C ± 2 ° C, respectively. Constant temperature detection line, characterized in that. 7. The constant temperature type according to claim 6, wherein the conductive wire is two, the insulation thickness (two wires) is 0.18 to 0.30 mm, the PS tape (pitch length) is 36 to 51 mm, and the thickness of the PVC or polyurethane sheath is 0.45 to 0.60 mm. Detection line. 7. The constant temperature type according to claim 6, wherein the conductive wire is two, the insulation thickness (two wires) is 0.20 to 0.35 mm, the PS tape (pitch length) is 39 to 60 mm, and the thickness of the PVC or polyurethane sheath is 0.50 to 0.65 mm. Detection line. 7. The wire according to claim 6, wherein the conductive wire is three, insulation thickness (1 wire) 0.18 to 0.30 mm, insulation thickness (2 wire) 0.20 to 0.35 mm, PS tape (pitch length) 45 to 102 mm, PVC or polyurethane sheath thickness A constant temperature sensing line, characterized in that 0.55 ~ 0.75mm.