KR102406002B1 - Heating cable with excellent flame resistance - Google Patents

Abstract

The present invention relates to a hot wire cable having excellent flame retardancy. Specifically, the present invention is not only excellent in flame retardancy, but also excellent in mechanical properties such as tensile strength and flex resistance, which are in a trade-off relationship with each other, and flexibility at the same time, and it is easy to control heat generation, and furthermore, it is structurally stable and has excellent appearance. , on the other hand, relates to a heated cable that is environmentally friendly and can reduce manufacturing costs.

Description

Heating cable with excellent flame resistance

The present invention relates to a hot wire cable having excellent flame retardancy. Specifically, the present invention is not only excellent in flame retardancy, but also excellent in mechanical properties such as tensile strength and flex resistance, which are in a trade-off relationship with each other, and flexibility at the same time, and it is easy to control heat generation, and furthermore, it is structurally stable and has excellent appearance. , on the other hand, relates to a heated cable that is environmentally friendly and can reduce manufacturing costs.

In general, in order to protect a driver and occupants from cold, a heating cable is embedded in a seat of a vehicle to enable heat generation by the supply of electricity. Such a hot wire cable has a structure in which a plurality of conductor core wires are individually coated with an insulating material in a bundle form and then wrapped with a covering material, and arranged in a zigzag on a mounting surface made of a flame retardant nonwoven fabric, etc. A planar heating element is formed.

Recently, the planar heating element formed from the heating wire cable is required to perform more uniform heating in the entire area, and to satisfy this demand, when the heating wire cables are arranged in a zigzag, the distance between adjacent cables is further narrowed. . However, as the distance between adjacent cables becomes narrower, the possibility that a fire may be caused during overheating due to disconnection of the cable or the like increases. Therefore, the hot wire cable should have excellent flame retardancy.

Such a heated cable must have excellent mechanical properties, such as tensile strength and bending resistance, to prevent damage from mechanical, chemical, and thermal stress caused by the occupant's load and vehicle body vibration when used inside the seat of a vehicle. In addition, in order to form a planar heating element by being arranged in a zigzag as described above, flexibility should also be excellent.

Conventional hot wire cables use a fluororesin such as Teflon as a material for a covering part that prevents a plurality of hot wire strands collected in a bundle form from being separated and protects the hot wire from external impact or pressure. However, the fluororesin has a problem of causing environmental problems, such as emitting toxic gas during incineration for disposal of the heating wire cable.

In addition, in consideration of the deterioration of mechanical properties such as tensile strength due to the addition of the flame retardant, when a resin having very excellent tensile strength is used, there is a problem in that the flexibility is largely insufficient or the cost is greatly increased.

Therefore, not only the flame retardancy is excellent, but also the mechanical properties such as tensile strength and flex resistance, which are in conflict with each other, and the flexibility are excellent at the same time, and the heat generation is easy to control, and furthermore, it is structurally stable and has excellent appearance, and on the other hand, it is environmentally friendly And there is an urgent need for a hot wire cable that can reduce the manufacturing cost.

An object of the present invention is to provide a hot wire cable which is excellent in flame retardancy and capable of avoiding or suppressing deterioration in tensile strength, flexibility, etc. by the added flame retardant.

In addition, an object of the present invention is to provide a hot wire cable that has excellent mechanical properties such as tensile strength and flex resistance, which are in a trade-off relationship with each other, and flexibility at the same time, and is easy to control the amount of heat generated.

Furthermore, an object of the present invention is to provide a hot wire cable that is structurally stable, has an excellent appearance, is environmentally friendly, and can reduce manufacturing costs.

In order to solve the above problems, the present invention,

A plurality of hot wires including a conductor core wire and an insulating layer surrounding the conductor core wire, or a plurality of hot wire sets including a plurality of conductor core wires and an insulating layer surrounding the set of the plurality of conductor core wires, and the plurality of hot wires or the plurality of hot wires A hot wire cable is provided, comprising a coating part surrounding the hot wire assembly, wherein the coating part is formed from a coating composition comprising a polymer resin and a flame retardant, and the content of the flame retardant is 15 to 25 wt% based on the total weight of the coating composition do.

Here, the flame retardant provides a hot wire cable, characterized in that it comprises at least one flame retardant selected from the group consisting of an organic phosphorus flame retardant, a melamine flame retardant, a phosphoric acid ester flame retardant, and a non-halogen flame retardant.

In addition, the polymer resin provides a hot wire cable, characterized in that it contains polyamide 12 (PA12), thermoplastic polyelastomer (TPE), or both.

On the other hand, a plurality of conductor core wires included in the hot wire set are twisted with each other at a set pitch, the plurality of hot wire sets are twisted with each other at a complex pitch, and the plurality of hot wire sets are in contact with each other and are formed by the plurality of hot wire sets that are combined. Empty inside the closed curve Including an inner space that is a space, the conductor core wire contains an alloy of copper (Cu) and tin (Sn), based on the total weight of the alloy, the content of tin (Sn) is 0.5 to 1% by weight A first conductor core wire and a second conductor core wire having a tin (Sn) content of 1.5 to 2 wt%, wherein the total resistance (R) according to Equation 1 below is 0.25 to 1.56 Ω/m , a heated cable is provided.

[Equation 1]

R = ((A resistance × B resistance)/(A resistance + B resistance)) × connection rate (λ)

In Equation 1 above,

A resistance is the resistance of the first conductor core / the number of the first conductor core,

B resistance is the resistance of the second conductor core / the number of the second conductor core,

The succession rate (λ) is according to Equation 2 below.

[Equation 2]

In Equation 2 above,

N is the composite pitch/composite pitch diameter.

Here, the diameter of the conductor core is 0.045 to 0.055 mm, the number of the first conductor cores is 4 to 12, the number of the second conductor cores is 30 to 38, and the resistance of one of the first conductor cores is 12.1 to 14.7. Ω/m, and the resistance of one strand of the second conductor core wire is 22.9 to 28.05 Ω/m, and provides a hot wire cable.

In addition, the number of the conductor core wires constituting one of the hot wire sets is 4 to 7, the aggregate pitch diameter is 0.17 to 0.23 mm, the number of the hot wire sets is 4 or more, and the composite pitch diameter is 0.55 to 0.8 mm, characterized in that It provides a hot wire cable.

And, the aggregate pitch is 3 to 7 mm, the composite pitch is characterized in that 2 to 5 mm, it provides a hot wire cable.

Furthermore, the thickness of the covering portion is 0.13 to 0.17 mm, and provides a hot wire cable, characterized in that the overall diameter of the hot wire cable is 0.8 to 1.0 mm.

In addition, the conductor core wire is characterized in that not heat-treated, it provides a hot wire cable.

And, it provides a hot wire cable, characterized in that it comprises at least one high tensile member selected from the group consisting of high tensile carbon fiber, high tensile glass fiber and aramid fiber in the inner space.

Furthermore, the insulating layer is formed by coating of polyurethane varnish, and the thickness of the insulating layer is 0.005 to 0.007 mm, to provide a hot wire cable.

Meanwhile, a plurality of hot wires including a conductor core wire and an insulating layer surrounding the conductive core wire are twisted together at a twist pitch of 8 to 14 mm to form a bundle, and the conductor core wire is made of copper (Cu) and tin (Sn). made of an alloy containing or more, and the coating portion is formed by a coating composition comprising a polymer resin having a tensile strength of 35 to 85 MPa and a flexural strength of 70 to 120 MPa, and 70 to 200 parts by weight of a flame retardant based on 100 parts by weight of the polymer resin, A heated cable is provided.

Here, the resistance of the conductor core wire provides a hot wire cable, characterized in that 0.2 to 0.6 Ω / m.

In addition, the conductor core wire is characterized in that not heat-treated, it provides a hot wire cable.

And, it provides a hot wire cable, characterized in that the diameter of the whole of the plurality of hot wires collected in the bundle form is 0.4 to 0.6 mm.

The hot wire cable according to the present invention exhibits excellent flame retardancy because the content of the flame retardant added to the coating is precisely controlled, and at the same time exhibits excellent mechanical properties such as tensile strength and bending resistance despite the addition of the flame retardant.

In addition, in the hot wire cable according to the present invention, by precisely controlling the material and number of conductor core wires, the set and complex structure of the conductor core wires, mechanical properties such as tensile strength and flex resistance, which are in a conflicting relationship with each other, and flexibility are simultaneously improved, and further It shows an excellent effect of easy control of the calorific value.

And, the heating cable according to the present invention is structurally stable and has an excellent appearance due to a specific structure, and exhibits an excellent effect of reducing the manufacturing cost without causing environmental problems by configuring the covering part with an environmentally friendly and relatively inexpensive material.

1 schematically shows a cross-sectional view according to an embodiment of a hot wire cable according to the present invention.
FIG. 2 schematically shows a longitudinal cross-sectional view of the hot wire cable of FIG. 1 .
Figure 3 schematically shows a cross-sectional view according to another embodiment of the hot wire cable according to the present invention.
FIG. 4 schematically shows a longitudinal cross-sectional view of the hot wire cable of FIG. 3 .

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed subject matter may be thorough and complete, and that the spirit of the present invention may be sufficiently conveyed to those skilled in the art. Like reference numerals refer to like elements throughout.

1 schematically shows a cross-sectional view according to an embodiment (hereinafter, referred to as a 'composite type') of a heating wire cable according to the present invention, and FIG. 2 schematically shows a longitudinal cross-sectional view of the heating wire cable of FIG. did it

1 and 2, the hot wire cable of the aggregate type according to the present invention is a plurality of conductor core wires 110, which are resistance wires that generate heat when electricity is supplied, and a set of the plurality of conductor core wires 110 as a whole. a plurality of hot wire sets 100 including an insulating layer 120 and being combined in contact with each other; a covering part 200 surrounding the plurality of hot wire sets 100; and an inner space 300 that is an empty space inside a closed curve formed by the plurality of hot wire sets 100 combined in contact with each other.

3 schematically shows a cross-sectional view according to another embodiment (hereinafter, referred to as 'set type') of the heating wire cable according to the present invention, and FIG. 4 schematically shows a longitudinal cross-sectional view of the heating wire cable of FIG. will be.

As shown in FIGS. 3 and 4 , the set-type hot wire cable according to the present invention has a conductor core wire 110 ′, which is a resistance wire that generates heat when electricity is supplied, and an insulating layer 120 that individually surrounds the conductor core wire 110 ′. '), a plurality of hot wires 100' including the bundled form may be included, and a covering part 200' surrounding the plurality of hot wires 100' of the bundle form may be included.

The conductor core wires 110 and 110' may be formed of an alloy of copper (Cu) and tin (Sn). In addition, the conductor core wires 110 and 110 ′ may further include alloying elements such as magnesium (Mg), zinc (Zn), and silver (Ag) in addition to tin (Sn). For example, the content of tin (Sn) included in the conductive core wire 110 based on the total weight of the conductive core wire 110 may be 0.5 to 7% by weight, and the total weight of the conductive core wire 110 ′. Based on the weight, the content of tin (Sn) included in the conductor core wire 110 ′ may be 1.6 to 2.0 wt%.

When the content of tin (Sn) included in the conductor core wire 110 is less than 0.5 wt% or the content of tin (Sn) included in the conductor core wire 110' is less than 1.6 wt%, the conductor core wires 110 and 110' While the mechanical properties such as tensile strength and bending resistance of the hot wire cable may be disconnected due to external impact or pressure, the content of tin (Sn) included in the conductor core wire 110 exceeds 0.7 wt% or when the content of tin (Sn) included in the conductor core wire 110' is more than 2.0 wt%, the flexibility of the conductor core wires 110 and 110' is lowered, so that the workability of the hot wire cable may be insufficient, and the resistance It may be difficult to control the amount of heat generated, such as excessive heat generation due to this increase.

The combined-type hot wire cable including the conductor core wire 110 may have a total resistance (R) of 0.25 to 1.56 Ω/m in order to exhibit an appropriate heating characteristic, and including the conductor core wire 110' The aggregate-type hot wire cable may have a total resistance (R) of 0.2 to 0.6 Ω/m in order to exhibit proper heating characteristics. Here, when the total resistance (R) of the hot wire cable of the aggregate type is less than 0.25 Ω/m or the total resistance (R) of the hot wire cable of the aggregate type is less than 0.2 Ω/m, the heating value may be insufficient, whereas 1.56 If it exceeds Ω/m or 0.6 Ω/m, excessive heat may cause burns or fire to vehicle occupants.

Meanwhile, the plurality of conductor core wires 110 may include two or more types of conductor core wires having different tin (Sn) contents. For example, the plurality of conductor core wires 110 have a tin (Sn) content The content of the first conductor core wire of 0.5 to 1% by weight and the tin (Sn) content may include a second conductor core wire of 1.5 to 2% by weight. Here, the resistance of one strand of the first conductor core may be 12.1 to 14.7 Ω/m, and the resistance of one strand of the second conductor core may be 22.9 to 28.05 Ω/m.

When the plurality of conductor core wires 110 includes the first conductive core wire and the second conductive core wire, each of the first and second conductive core wires according to the total resistance (R) of the hot wire cable of the aggregate type The resistance and the number may satisfy Equation 1 below. For example, the number of the first conductor core wire may be 4 to 12, and the number of the second conductor core may be 30 to 38.

[Equation 1]

R = ((A resistance × B resistance)/(A resistance + B resistance)) × connection rate (λ)

In Equation 1 above,

A resistance is the resistance of the first conductor core / the number of the first conductor core,

B resistance is the resistance of the second conductor core / the number of the second conductor core,

The succession rate (λ) is according to Equation 2 below.

[Equation 2]

In Equation 2 above,

N is the composite pitch/composite pitch diameter.

In order to implement the appropriate resistance of the aggregation type hot wire cable, the diameter of the conductor core wire 110 is about 0.045 to 0.055 mm, and the total number of the conductor core wires 110 may be 28 to 42. In addition, since the resistance of the hot wire cable is determined by the cross-sectional area of the plurality of conductor core wires 110 constituting it, the diameter and the number of the conductor core wires 110 may be inversely proportional to each other.

Specifically, when the diameter of the conductor core wire 110 is less than 0.045 mm, there is a problem that disconnection of the conductor core wire 110 occurs frequently, whereas when the diameter of the conductor core wire 110 is more than 0.055 mm, the desired resistance is obtained. To implement, the number of the conductor core wires 110 is less than 28, and in this case, the flexibility of the hot wire cable may be greatly reduced. Furthermore, when the number of the conductor core wires 110 is 28 to 42, there is an aspect of improving the flexibility of the hot wire cable as well as an aspect of excellent power efficiency due to the skin effect.

On the other hand, in order to implement the appropriate resistance of the aggregation type hot wire cable, the diameter of the conductor core wire 110' is about 0.01 to 0.1 mm, preferably about 0.05 mm or less, and the The number may be 30 or more, preferably 40 to 60. In addition, since the resistance of the hot wire cable is determined by the cross-sectional area of the plurality of conductor core wires 110 ′ constituting it, the diameter and the number of the conductive core wires 110 ′ may be inversely proportional to each other.

Specifically, when the diameter of the conductive core wire 110' is less than 0.01 mm, the number of the conductive core wire 110' exceeds 60 in order to realize the desired resistance. In this case, the conductive core wire 110' On the other hand, when the diameter of the conductor core wire 110' is greater than 0.1 mm, the number of the conductor core wire 110' is less than 30 in order to realize the desired resistance, while there is a problem that disconnection occurs frequently. The flexibility of the hot wire cable may be greatly reduced. Furthermore, when there are more than 30 conductor core wires 110 ′, not only the flexibility of the hot wire cable is improved, but also the power efficiency is excellent due to the skin effect.

Preferably, the conductor core wires 110 and 110' may not be heat-treated. Since the core wire made of a normal metal material has high strength, it may be heat treated to improve flexibility when bending or the like is required. However, there is a problem in that tensile strength and bending resistance are deteriorated during heat treatment of the conductor core wires 110 and 110'. Therefore, since the conductor core wires 110 and 110' are not heat treated, they exhibit excellent tensile strength and flex resistance, and as described above, the flexibility can be further improved in a way that improves the flexibility by reducing the diameter and increasing the number. .

The insulating layers 120 and 120' perform a function of suppressing the occurrence of local excessive heat or fire in the heated wire cable by some of the plurality of conductor core wires 110 and 110' being disconnected by external impact, pressure, or the like. Specifically, when the conductor core wires 110 and 110' are not covered by the insulating layers 120 and 120', that is, the disconnected conductor core wires 110 and 110' and the unbroken conductor core wires 110 and 110' are in contact with each other and the If current flows also in the disconnected conductor core wires 110 and 110', the resistance increases due to a decrease in the cross-sectional area of the entire conductor core wires 110 and 110' at the disconnected portion of the conductor core wires 110 and 110', causing excessive heat locally in the heated cable. This may cause burns or a fire to the occupants.

Accordingly, the conductor core wires 110.110' disconnected by the set of the conductor core wires 110 being covered by the insulating layer 120 or by each of the conductor core wires 110' being covered by the insulating layer 120'. By preventing the current from flowing, resistance at the disconnected portion of the conductor core wires 110 and 110 ′ increases, thereby preventing excessive local heat generation. Here, the insulating layers 120 and 120' may be formed by coating of polyurethane varnish having excellent tensile strength and advantageous in forming a thin film, and the thickness of the insulating layers 120 and 120' is, for example, about 0.005 to 0.007. mm may be.

The hot wire 10 forming the hot wire set 100 is structurally stable and has an excellent appearance with a flat surface while implementing appropriate heating characteristics by having an appropriate resistance. ) may be 4 to 7 pieces, and the number of the hot wire sets 100 may be 4 or more, preferably 6 pieces.

In addition, the plurality of conductor core wires 110 forming the hot wire set 100 are assembled in a twisted state with a twist pitch, that is, an aggregate pitch of 3 to 7 mm, and the hot wire set 100 has a twisted pitch, that is, a composite pitch of 2 It can be combined in a twisted state from 5 mm to 5 mm. In addition, the set pitch diameter, which is the diameter of an imaginary circle formed by twisting of the plurality of conductor core wires 110 constituting one of the hot wire sets 100, may be about 0.17 to 0.23 mm, and the combined hot wire set ( The compound pitch diameter, which is the diameter of an imaginary circle formed by the twist of 100), may be 0.55 to 0.8 mm. In addition, the overall diameter of the hot wire cable may be about 0.8 to 1.0 mm.

Here, when the set pitch of the conductor core wire 110 is less than 3 mm or the composite pitch of the hot wire set 100 is excessively short, less than 2 mm, the bending resistance of the hot wire cable is improved, but productivity is greatly reduced, and in particular, the conductor Since the resistance of the core wire 110 is greatly increased, it may be difficult to control the amount of heat generated, such as excessive heat generation, and the flexibility may be greatly reduced, whereas the set pitch of the conductor core wire 110 is more than 7 mm or the hot wire set If the composite pitch of (100) is excessively long, more than 5 mm, the bending resistance of the hot wire cable may be insufficient.

On the other hand, in the aggregation type hot wire cable according to the present invention, a plurality of hot wires 100' formed by coating the insulating layer 120' on the surface of the conductor core wire 110' are assembled in a bundle form, In particular, the plurality of hot wires 100 ′ may be assembled by being twisted with each other at a constant pitch. Here, the twist pitch of the plurality of hot wires 100 ′ may be, for example, 8 to 14 mm.

When the twist pitch of the hot wire 100' is excessively short, less than 8 mm, the bending resistance of the hot wire cable is improved, but productivity is greatly reduced, and in particular, the resistance of the hot wire 100' is greatly increased to generate excessive heat, etc. While it may be difficult to control the amount of heat generated and flexibility may be greatly reduced, if the twist pitch is excessively long, more than 14 mm, the bending resistance of the hot wire cable may be insufficient. In addition, the total diameter of the plurality of the assembled hot wire 100' may be about 0.4 to 0.6 mm, preferably about 0.5 mm.

In the present invention, the plurality of hot wire sets 100 or the plurality of hot wires 100' are entirely surrounded by the covering parts 200 and 200'. The covering part 200 exists only outside the hot wire set 100 and does not exist in the inner space 300 , which is an empty space inside a closed curve formed by contacting the plurality of hot wire sets 100 with each other. Meanwhile, the covering part 200' exists not only outside the heating wire 100' but also in a space between the plurality of heating wires 100'.

The covering portions 200 and 200 ′ not only allow the heat dissipation distribution on the surface of the hot wire cable to be uniformly made, but also have a structure in which the plurality of hot wire sets 100 are complexed and the hot wire despite external force, bending, twisting, etc. (100') can perform a role of stably fixing the assembled structure, and protecting the conductor core wires 110 and 110' and the heating wire set 100 and the heating wire 100' from external impact or pressure. have.

The coating parts 200 and 200' may be formed from a coating composition in which a polymer resin and a flame retardant are mixed, and the thickness of the coating parts 200 and 200' may be about 0.13 to 0.17 mm. The polymer resin may have a tensile strength of 35 to 85 MPa and a flexural strength of 70 to 120 MPa. For example, the polymer resin may be polyamide 12 (PA12), thermoplastic polyelastomer (TPE), or the like.

When the tensile strength of the polymer resin is less than 35 MPa, when a large amount of a flame retardant is added to provide sufficient flame retardancy to the coating parts 200 and 200 ′, the mechanical properties of the coating parts 200 and 200 ′ are greatly reduced, so that external impact or pressure While the conductor core wires 110 and 110' and the hot wire assembly 100 and the hot wire 100' cannot be sufficiently protected from the above, when the flexural strength of the polymer resin exceeds 120 MPa, the flexibility of the hot wire cable is insufficient. can do.

The flame retardant includes organic flame retardants such as bromine flame retardants, halogen flame retardants such as chlorine flame retardants, organic phosphorus flame retardants, aluminum hydroxide, magnesium hydroxide, antimony trioxide, antimony oxide, red phosphorus flame retardants, boron flame retardants, silica flame retardants, melamine flame retardants, Inorganic flame retardants such as phosphoric acid ester flame retardants and inorganic phosphorus flame retardants may be included.

However, when the flame retardant is a halogen-based flame retardant such as a bromine-based or chlorine-based flame retardant, there is a problem in that environmental problems such as dioxin are emitted during soldering work or incineration for disposal, thereby causing environmental problems and reducing workability. Accordingly, the flame retardant is preferably a non-halogen flame retardant, and in particular, in consideration of compatibility with the polymer resin, organic and non-halogen flame retardants such as organic phosphorus flame retardants, melamine flame retardants, and phosphoric acid ester flame retardants are preferable.

The content of the flame retardant may be 15 to 25% by weight based on the total weight of the coating composition. If the content of the flame retardant is less than 15% by weight, the flame retardancy of the hot wire cable may be insufficient, whereas if it exceeds 25 wt%, the flame retardancy of the planar heating element including the hot wire cable is insufficient, and the tensile strength of the hot wire cable, resistance Flexibility, flexibility, etc. may be reduced.

Specifically, the flame retardancy of the hot wire cable must be excellent in both the flame retardancy of the hot wire cable itself and the flame retardancy of the planar heating element on which the hot wire cable is mounted. According to the present inventors, since the flame retardant of the hot wire cable itself is improved as the content of the flame retardant added to the coating composition increases, the content of the flame retardant should be 15% by weight or more, but when the content of the flame retardant is more than 25% by weight, such a hot wire cable It was confirmed experimentally for the first time that the flame retardancy of this mounted planar heating element is rather lowered.

Presumably, the planar heating element in which the heating wire cable is arranged and fixed on the upper surface in a zigzag manner has an adhesive tape pad formed on the lower surface to attach the flat heating element to a car seat, etc., and when the heating wire cable is ignited at a specific point Flame spreads along the hot wire cable using the coating composition and the adhesive tape as fuel. When the content of the flame retardant added to the coating composition is at a certain level, that is, 25 wt% or less, the viscosity of the coating composition is low and the flame spreads It seems that the spread of the flame is stopped by falling in the process of being burned.

On the other hand, when the content of the flame retardant added to the coating composition is at a certain level, that is, more than 25% by weight, the viscosity of the coating composition is high and the flame appears to be stably spread along the hot wire cable.

In the combination type hot wire cable according to the present invention, the inner space 300 allows the plurality of hot wire sets 100 to stably maintain the complex structure, and at the same time, the heat dissipation distribution by the hot wire cable to make it uniform.

When the coating composition penetrates a part of the inner space 300, when the hot wire cable is twisted or subjected to a strong external force, the content of the coating composition penetrating into the inner space 300 is in the twisting direction or in the direction in which an external force is applied. Since it changes according to the change, there may be a deformation in the structure and arrangement of the hot wire set 100 .

In addition, a tension member made of a material such as high tensile material, for example, high tensile carbon fiber, high tensile glass fiber, aramid fiber, etc., is inserted into the inner space 300 to further improve the tension of the hot wire cable. can

[Example]

1. Preparation example

Each of the hot wire cable specimens of the aggregate type having the configuration shown in Table 1 below was prepared.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 conductor 1st conductor core wire (pcs) 8 42 8 8 8 2nd conductor wire (pcs) 34 - 34 34 34 Conductor diameter (mm) 0.055 Total resistance (Ω/m) 0.55 insulating layer polyurethane varnish set structure 7 conductor cores per hot wire set composite structure 6 hot wire sets cover layer Suzy Polyamide 12 (PA12) Flame Retardant (wt%) 20 20 10 30 35

- 1st conductor core wire: copper (Cu) + tin (Sn) core wire with tin (Sn) content of 0.7 wt%

- Second conductor core wire: copper (Cu) + tin (Sn) core wire with stock (Sn) content of 1.8 wt%

- Flame retardant: Phosphorus flame retardant

2. Physical property evaluation

1) Flexural resistance evaluation

Example 1 and Comparative Example 1 After repeatedly performing a 180° bending test by applying a load of 910 g to each of the hot wire cable specimens, the disconnection rate of the conductor core wires (the number of disconnected conductor core wires/the total number of conductor core wires * 100) was 20 % was measured, and if the number of bending was less than 150,000 times, the bending resistance was considered insufficient. The results of the bending test are shown in Table 2 below.

Example 1 Comparative Example 1 number of bends about 250,000 times about 70,000 times

- Number of bending: The number of bendings when the disconnection rate of the conductor core (the number of disconnected conductor cores / the total number of conductor cores * 100) is 20%

As shown in Table 2, the hot wire cable of Example 1 formed by a specific combination of two types of conductor cores having different tin (Sn) content compared to the hot wire cable of Comparative Example 1 using one type of conductor core It was confirmed that the bending resistance was significantly improved on the premise that the same resistance was implemented.

2) Flame retardant evaluation

Examples 1 and Comparative Examples 2 to 4 A combustion test was performed by heating one end of a planar heating element prepared by arranging and fixing each hot wire cable on the upper surface of the planar nonwoven fabric in a zigzag, and the combustion length along the hot wire cable must not exceed 50 mm is acceptable. The combustion test was carried out for each of 8 cases in which the adhesive tape pad was present and not present on the lower surface of the planar heating element. The combustion test results are shown in Table 3 below.

Combustion length evaluation Adhesive tape pad presence × Adhesive tape pad presence ○ Example 1 8 pass 8 pass Comparative Example 2 5 pass/3 fail 8 pass Comparative Example 3 8 pass 6 passed/2 failed Comparative Example 4 8 pass 4 Pass/4 Fail

As shown in Table 3, the hot wire cable of Example 1, in which the content of the flame retardant contained in the coating composition is precisely controlled, has excellent flame retardancy as well as the flame retardancy of the hot wire cable itself, while the flame retardancy of the planar heating element on which the hot wire cable is disposed, The hot wire cable of Comparative Example 2 having an insufficient content of the flame retardant has insufficient flame retardancy of the hot wire cable itself, and the hot wire cables of Comparative Examples 3 and 4 having an excessive content of the flame retardant have excellent flame retardancy of the hot wire cable itself, but these hot wire cables are arranged It was confirmed that the flame retardancy of the planar heating element was insufficient.

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims described below. will be able to carry out Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all should be considered to be included in the technical scope of the present invention.

100: hot wire set 100': hot wire
200: covering part 300: internal space

Claims (15)

A plurality of hot wire sets including a plurality of conductor core wires and an insulating layer surrounding the set of the plurality of conductor core wires, and a covering part surrounding the plurality of hot wire sets,
The coating portion is formed from a coating composition comprising a polymer resin and a flame retardant,
The content of the flame retardant is 15 to 25% by weight based on the total weight of the coating composition,
A plurality of conductor core wires included in the hot wire set are twisted with each other at a set pitch, and the plurality of hot wire sets are twisted with each other at a complex pitch,
and an inner space that is an empty space inside a closed curve formed by the plurality of hot wire sets combined in contact with each other,
The conductor core wire includes an alloy of copper (Cu) and tin (Sn), and the first conductor core wire and the tin ( and a second conductor core wire having a content of Sn) of 1.5 to 2% by weight,
The total resistance (R) according to Equation 1 below is characterized in that 0.25 to 1.56 Ω / m, the hot wire cable.
[Equation 1]
R = ((A resistance × B resistance)/(A resistance + B resistance)) × connection rate (λ)
In Equation 1 above,
A resistance is the resistance of the first conductor core / the number of the first conductor core,
B resistance is the resistance of the second conductor core / the number of the second conductor core,
The succession rate (λ) is according to Equation 2 below.
[Equation 2]

In Equation 2 above,
N is the composite pitch/composite pitch diameter. According to claim 1,
The flame retardant comprises at least one flame retardant selected from the group consisting of an organic phosphorus flame retardant, a melamine flame retardant, a phosphoric acid ester flame retardant, and a non-halogen flame retardant, a hot wire cable. 3. The method of claim 2,
The polymer resin comprises polyamide 12 (PA12), thermoplastic polyelastomer (TPE), or both, a hot wire cable. delete According to claim 1,
The diameter of the conductor core is 0.045 to 0.055 mm, the number of the first conductor core is 4 to 12, the number of the second conductor core is 30 to 38, and the resistance of one of the first conductor core is 12.1 to 14.7 Ω/ m, and the resistance of one strand of the second conductor core is 22.9 to 28.05 Ω/m, the hot wire cable. 6. The method of claim 5,
The number of conductor core wires constituting one of the hot wire sets is 4 to 7, the aggregate pitch diameter is 0.17 to 0.23 mm, the number of the hot wire sets is 4 or more, and the composite pitch diameter is 0.55 to 0.8 mm, characterized in that, heated cable. 7. The method of claim 6,
The aggregation pitch is 3 to 7 mm, and the composite pitch is 2 to 5 mm, characterized in that the hot wire cable. According to claim 1,
The thickness of the coating portion is 0.13 to 0.17 mm, the hot wire cable, characterized in that the diameter of the whole hot wire cable is 0.8 to 1.0 mm. According to claim 1,
The conductor core wire is characterized in that not heat-treated, hot wire cable. According to claim 1,
The hot wire cable, characterized in that it comprises at least one high tensile member selected from the group consisting of high tensile carbon fiber, high tensile glass fiber and aramid fiber in the inner space. 4. The method according to any one of claims 1 to 3,
The insulating layer is formed by coating of polyurethane varnish, the thickness of the insulating layer is 0.005 to 0.007 mm, hot wire cable. 4. The method according to any one of claims 1 to 3,
A plurality of hot wires including a conductor core wire and an insulating layer surrounding the conductive core wire are twisted together at a twist pitch of 8 to 14 mm to form a bundle,
The conductor core wire is made of an alloy containing copper (Cu) and tin (Sn), and the content of tin (Sn) is 1.6 to 2.0 wt% based on the total weight of the alloy, and the diameter of the conductor core wire is 0.01 to 0.1 mm,
The number of the hot wire is 30 or more,
The coating portion is formed by a coating composition comprising a polymer resin having a tensile strength of 35 to 85 MPa and a flexural strength of 70 to 120 MPa, and 70 to 200 parts by weight of a flame retardant based on 100 parts by weight of the polymer resin. 13. The method of claim 12,
The resistance of the conductor core wire is 0.2 to 0.6 Ω/m, characterized in that the hot wire cable. 13. The method of claim 12,
The conductor core wire is characterized in that not heat-treated, hot wire cable. 13. The method of claim 12,
A hot wire cable, characterized in that the total diameter of the plurality of hot wires assembled in the bundle form is 0.4 to 0.6 mm.

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