KR20200087092A - Cable having an excellent fire-resistance - Google Patents

Abstract

The present invention relates to a highly flame-retardant cable. Specifically, the present invention relates to a highly flame-retardant cable which enables implementation of the flame retardancy standard class of IEC 60332-3 Cat.A, and at the same time, by having a reduced outer diameter, enables flexibility to be improved and manufacturing costs to be reduced.

Description

Highly flame-retardant cable {Cable having an excellent fire-resistance}

The present invention relates to a high flame retardant cable. Specifically, the present invention relates to a high flame retardant cable capable of improving the flexibility by reducing the outer diameter while simultaneously implementing flame retardancy of the standard IEC 60332-3 Cat.A grade, and reducing manufacturing cost.

Medium voltage (MV) power distribution cables used in buildings, tunnels, plants, etc. mainly require flame retardancy of the standard IEC 50332-3 Cat.C class, but reinforce international regulations and Cat.B or Cat.A class The demand for distribution cables in possession is increasing.

In addition, most of the insulation layer of the cable for distribution is composed of a crosslinked polyethylene (XLPE) material that is not flame retardant and has a high heat transfer rate, and is the most severe in the case of a cable with a non-covered structure without armor even when a sheath layer having high flame resistance is applied. It is difficult to meet the flame retardancy of the flame retardant specification IEC 60332-3-22 Cat.A grade, especially the medium voltage (MV) power distribution cable has a higher volume than the low voltage (LV) power distribution cable. It has a structure that is vulnerable to flame retardance because the volume ratio of the volume is more than 10%.

That is, in the case of a conventional medium voltage distribution cable, the primary function of preventing the propagation of flames and preventing the melting of the insulating layer in an environment where a flame is applied is performed by the high flame retardant sheath layer, but the thickness of the sheath layer is relatively thin and the insulating layer It was difficult to satisfy the flame retardancy of the Cat.A grade even when the thickness of the film was simply added to the sheath layer or simply a flame retardant taping layer to block flames inside the sheath layer.

Meanwhile, FIG. 1 schematically shows a cross-sectional structure of one embodiment of a conventional medium voltage distribution cable.

As shown in FIG. 1, one embodiment of a conventional medium voltage cable includes a conductor 1, an inner semiconducting layer 2, an insulating layer 3, an outer semiconducting layer 4, a metal shielding layer 5, The first flame-retardant taping layer (glass taping layer) 6, the bedding layer 7, the second flame-retardant taping layer (glass taping layer) 8, the outer sheath layer 9, etc. have a structure in which they are sequentially stacked. Since a plurality of flame-retardant taping layers (glass taping layers) are applied, the cable manufacturing cost increases due to the taping process cost and excessive material cost, and the overall outer diameter increases, thereby deteriorating the flexibility of the cable.

Accordingly, there is an urgent need for a highly flame-retardant cable capable of realizing flame retardance of the standard IEC 60332-3 Cat.A grade and reducing the outer diameter to improve flexibility and reduce manufacturing cost.

An object of the present invention is to provide a high flame retardant cable capable of implementing flame retardancy of the standard IEC 60332-3 Cat.A grade.

In addition, an object of the present invention is to provide a high flame retardant cable capable of improving flexibility by reducing an outer diameter while simultaneously implementing high flame retardant characteristics.

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

At least one core including a conductor, an inner semiconducting layer surrounding the conductor, an insulating layer surrounding the inner semiconducting layer, an outer semiconducting layer surrounding the insulating layer, and a metal shielding layer surrounding the outer semiconducting layer; A bedding layer surrounding the at least one core and formed from a flame retardant composition; And an outer sheath layer formed by extruding a sheath composition having an oxygen index of 35 to 47% and surrounding the bedding layer, wherein the flame retardant composition includes a base resin and a flame retardant, and a volume ratio of the bedding layer and the insulating layer. Is 1:1 to 3:1, when performing the standard IEC 60332-3-22 Cat.A flame retardant evaluation, provides a high flame retardant cable with a combustion length of 2.5 m or less.

Here, the oxygen index of the bedding layer is characterized in that at least 45%, to provide a high flame retardant cable.

In addition, it provides a high flame retardant cable, characterized in that the room temperature elongation of the bedding layer is 40% or more.

On the other hand, when the core is one, it characterized in that it further comprises a glass taping layer between the core and the bedding layer, provides a high flame retardant cable.

In addition, the base resin includes ethylene vinyl acetate resin, and the melt index of the ethylene vinyl acetate resin is 3 to 5, to provide a high flame retardant cable.

And, the base resin provides a high flame retardant cable, characterized in that it further comprises an ethylene copolymer.

Here, based on 100 parts by weight of the base resin, the content of the ethylene vinyl acetate resin is 85 to 100 parts by weight, characterized in that the content of the ethylene copolymer is 0 to 15 parts by weight, provides a high flame retardant cable.

And, the ethylene vinyl acetate resin provides a high flame retardant cable, characterized in that the content of the vinyl acetate monomer is 25 to 30% by weight based on the total weight thereof.

In addition, the ethylene copolymer provides a high flame retardant cable, characterized in that the melting point is 60 to 80 ℃.

Here, the ethylene copolymer is ethylene-octene copolymer or ethylene-butene copolymer, characterized in that it comprises a high flame-retardant cable.

On the other hand, the flame retardant provides a high flame retardant cable, characterized in that it comprises a metal hydroxide containing magnesium hydroxide or aluminum hydroxide or both.

In addition, the magnesium hydroxide or the aluminum hydroxide provides a high flame retardant cable, characterized in that the surface treatment with a hydrophobic surface treatment agent.

And, based on 100 parts by weight of the base resin, characterized in that the content of the flame retardant is 240 to 280 parts by weight, provides a high flame retardant cable.

Here, the flame retardant composition, based on 100 parts by weight of the base resin, characterized in that it further comprises 5 to 15 parts by weight of at least one inhibitor selected from the group consisting of boric acid compounds, antimony compounds and molybdenum compounds, high flame retardant Provide cable.

On the other hand, as a composition for high flame retardant bedding, a base resin and a flame retardant, the base resin comprises an ethylene vinyl acetate resin, the flame retardant comprises a metal hydroxide, and the ethylene vinyl acetate resin has a melt index of 3 to 5 It provides a high flame retardant bedding composition, the oxygen index is 45% or more.

Here, it provides a composition for high flame retardant bedding, characterized in that the room temperature elongation is 40% or more.

And, the base resin provides a composition for high flame retardant bedding, characterized in that it further comprises an ethylene copolymer.

In addition, based on 100 parts by weight of the base resin, the content of the ethylene vinyl acetate resin is 85 to 100 parts by weight, characterized in that the content of the ethylene copolymer is 0 to 15 parts by weight, provides a flame retardant bedding composition .

And, the ethylene vinyl acetate resin provides a composition for high flame retarding bedding, characterized in that the content of the vinyl acetate monomer is 25 to 30% by weight based on the total weight thereof.

Here, the ethylene copolymer is characterized in that the melting point is 60 to 80 ℃, provides a flame retardant bedding composition.

In addition, the ethylene copolymer provides a composition for high flame retardant bedding, characterized in that it comprises an ethylene-octene copolymer, an ethylene-butene copolymer, or both.

And, the flame retardant provides a composition for high flame retardant bedding, characterized in that it comprises a metal hydroxide containing magnesium hydroxide or aluminum hydroxide or both.

Furthermore, the magnesium hydroxide or the aluminum hydroxide provides a composition for high flame retarding bedding, characterized in that the surface treatment with a hydrophobic surface treatment agent.

In addition, based on 100 parts by weight of the base resin, the content of the flame retardant is 240 to 280 parts by weight, it provides a composition for high flame retardant bedding.

Here, based on 100 parts by weight of the base resin, characterized in that it further comprises 5 to 15 parts by weight of one or more inhibitors selected from the group consisting of boric acid compounds, antimony compounds and molybdenum compounds, provides a composition for high flame retarding bedding do.

The high flame retardant cable according to the present invention exhibits an excellent effect of realizing high flame retardancy of the standard IEC 60332-3 Cat.A grade by imparting flame retardancy to the bedding layer.

In addition, the high flame-retardant cable according to the present invention can improve flexibility by reducing the outer diameter by up to 6.9%, despite implementing excellent flame retardancy by the specific material forming the bedding layer and the thickness of the precisely controlled bedding layer. By excluding a large number of glass tapes, material costs and taping process costs can be saved, thereby exhibiting an excellent effect of reducing manufacturing costs.

1 schematically shows a cross-sectional structure of one embodiment of a conventional medium voltage distribution cable.
2 schematically shows a cross-sectional structure of one embodiment of a high flame retardant medium voltage distribution cable according to the present invention.
3 schematically shows a cross-sectional structure of another embodiment of a high flame retardant medium voltage distribution cable according to the present invention.

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 to ensure that the disclosed contents are thorough and complete, and that the spirit of the present invention is sufficiently conveyed to those skilled in the art. Throughout the specification, the same reference numbers refer to the same components.

2 schematically shows a cross-sectional structure of one embodiment of a high flame retardant medium voltage distribution cable according to the present invention, and FIG. 3 schematically shows a cross-sectional structure of another embodiment.

As shown in FIG. 2, the high flame-retardant cable according to the present invention is a Class 2 or 5 conductor 10 satisfying the standard IEC 60228, and the conductor 10 is wrapped and extruded from a semiconducting compound or transversely cross-conducted tape The inner semiconducting layer 20, which may be formed by wrapping the inner semiconducting layer 20 and crosslinking polyolefin (XLPO), ethylene propylene rubber (EPR), hard ethylene propylene rubber (HEPR), polyvinyl chloride (PVC), An insulating layer 30 made of silicone rubber, etc., an outer semiconducting layer 40 that surrounds the insulating layer 30 and can be formed by extrusion of a semiconducting compound or by traverse of a semiconducting tape, the outer semiconducting layer 40 A metal shielding layer 50 formed by a metal tape or a metal braided layer made of a material such as copper, aluminum, and alloys thereof, and surrounding the metal shielding layer 50, urethane coated glass or silicon, Tape glass taping layer 60 formed by the transverse winding of a glass tape containing an inorganic coating glass such as ceramic, a bedding layer 70 formed from the above-mentioned bedding composition surrounding the glass taping layer 60 , May include an outer sheath layer 80 formed by extruding the bedding layer 70 and extruding a flame retardant compound having an oxygen index of 35 to 47%.

In addition, as shown in FIG. 3, the high flame-retardant cable according to the present invention is a Class 2 or 5 conductor 10 that satisfies the standard IEC 60228, and the conductor 10 is wrapped and a semiconducting compound is extruded or semiconductive tape. The inner semiconducting layer 20, which can be formed by the transverse winding of, wraps the inner semiconducting layer 20 and crosslinks polyolefin (XLPO), ethylene propylene rubber (EPR), hard ethylene propylene rubber (HEPR), polyvinyl chloride (PVC) ), an insulating layer 30 made of silicone rubber, etc., an outer semiconducting layer 40 and an outer semiconducting layer 40 that may be formed by wrapping the insulating layer 30 and extruding a semiconductive compound or transversely of a semiconductive tape. 40) surrounding a plurality of cores including a metal shielding layer 50 formed by a metal tape or a metal braided layer made of a material such as copper, aluminum, and alloys thereof, filling an empty space between the plurality of cores A faithful bedding layer 70' formed from the above-mentioned bedding composition, an outer sheath layer 80 formed by extruding a flame retardant compound having an oxygen index of 35 to 47% and surrounding the faithful bedding layer 70' It can contain.

In general, the bedding layer applied to the cable is applied to protect the internal configuration of the bedding layer from external physical impact or pressure, and fill the empty space inside the cable to improve the structural stability of the cable and the roundness of the cable cross-section. This is the configuration.

On the other hand, the present inventors have changed the idea through a technical idea that no one has previously thought of, that is, a standard IEC 60332-3 Cat.A grade without a separate configuration for realizing flame retardancy by imparting a flame retardancy of 45% or more to the bedding layer The present invention was completed by confirming through cable design and testing that it is possible to improve flexibility by reducing the outer diameter of the cable and to reduce the manufacturing cost of the cable while realizing the high flame retardancy of.

Specifically, in the high flame-retardant cable according to the present invention, the bedding layers 70 and 70' are volume ratios of the bedding layers 70 and 70' and the insulating layer 30 on the premise that they are formed from a flame-retardant composition described later. By adjusting the ratio from 1:1 to 3:1, it is possible to realize excellent flame retardancy, while reducing the flame retardant taping layer (glass taping layer), thereby reducing the outer diameter of the cable to improve flexibility and minimize manufacturing cost. have. In the case of having a plurality of cores as in the embodiment shown in FIG. 3, the volume of the insulating layer 30 may be a sum of the volumes of the insulating layers 30 of each core.

Here, when the volume ratio between the bedding layers 70 and 70' and the insulating layer 30 is less than 1:1, high flame retardancy of the standard IEC 60332-3 Cat.A grade cannot be achieved, while it exceeds 3:1. The outer diameter of the cable is excessive and flexibility may be deteriorated, and the manufacturing cost of the cable may be unnecessarily increased.

Meanwhile, the flame retardant composition forming the bedding layers 70 and 70' may include a base resin, a flame retardant, a flame retardant, a filler, and other additives.

The base resin may include ethylene vinyl acetate (EVA) resin alone or may further include an ethylene copolymer.

The ethylene vinyl acetate (EVA) resin may have a vinyl acetate monomer content of 25 to 30% by weight based on the total weight thereof, and implement basic properties such as strength and elongation of the bedding composition, and the base resin and flame retardant Compatibility with additives such as can be improved.

The content of the ethylene vinyl acetate resin may be 85 to 100 parts by weight based on 100 parts by weight of the base resin. Here, when the content of the ethylene vinyl acetate resin is less than 85 parts by weight or the content of the vinyl acetate monomer is less than 25% by weight, the cost of the composition for bedding increases and the compatibility between the base resin and additives such as flame retardants decreases. While the room temperature elongation of the bedding composition may be insufficient to less than 40%, when the content of the vinyl acetate monomer is more than 30% by weight, the polar group content of the base resin is excessive and contact with the bedding layer formed from the bedding composition There is a problem that the laying workability is deteriorated, such as the sheath layer and the phenomenon of sticking, which makes it difficult to peel the sheath.

In addition, the ethylene vinyl acetate (EVA) resin may have a Melting Index (MI) of 3 to 5. Here, when the melt index (MI) of the ethylene vinyl acetate (EVA) resin is less than 3, compatibility with additives such as a flame retardant is greatly reduced, making it difficult to uniformly disperse the additive and consequently, properties such as flame retardancy can be realized. While the extrusion process is impossible due to the decrease in elongation at room temperature, when the melt index (MI) is greater than 5, when the cable according to the present invention has the three-phase structure of FIG. 3, faithful extrusion filling the empty space between the cores is impossible. there is a problem.

On the other hand, the ethylene copolymer may improve the heat resistance, flame retardancy, etc. of the bedding composition, for example, may include a copolymer of ethylene monomers and olefin monomers such as propylene, butene, octene, etc. Preferably, it may include an ethylene-octene copolymer, an ethylene-butene copolymer, and the like, and a melting point may be 60 to 80°C.

The content of the ethylene copolymer may be 0 to 15 parts by weight based on 100 parts by weight of the base resin. When the melting point of the ethylene copolymer is less than 60°C, heat resistance and flame retardancy of the bedding composition may be lowered, and when the melting point of the ethylene copolymer is greater than 80°C or the content is more than 15 parts by weight, the base resin and the flame retardant Compatibility with additives, such as, decreases, and the room temperature elongation of the bedding composition may be insufficient to less than 40%.

The flame retardant may include a metal hydroxide such as magnesium hydroxide or aluminum hydroxide, and the metal hydroxide may be surface treated with a hydrophobic surface treatment agent such as vinylsilane or fatty acid to improve compatibility with the base resin. The metal hydroxide is decomposed when flame is applied to the bedding layer formed from the bedding composition, thereby realizing flame retardancy through dehydration and endothermic reactions, and char, which is a carbide formed during combustion of the bedding layer, is more robust. So that they can withstand flames.

The content of the flame retardant may be 240 to 280 parts by weight based on 100 parts by weight of the base resin, and when the content of the flame retardant is less than 240 parts by weight, flame retardancy such as oxygen index may be insufficient, whereas when it exceeds 280 parts by weight, the base Compatibility with the resin is lowered, and thus flexibility, extrudability, etc. of the bedding composition may be reduced.

The flame retardant may include a boric acid compound such as zinc borate, an antimony compound such as antimony trioxide, a molybdenum compound, etc., which performs a function of suppressing the generation of toxic gas during combustion, based on 100 parts by weight of the base resin It may be included in parts by weight. Here, when the content of the retardant is less than 5 parts by weight, the retardation effect may be insufficient, whereas when it is more than 15 parts by weight, flexibility and extrudability of the bedding composition may be deteriorated.

The filler performs a function that can reduce the manufacturing cost without lowering the physical properties of the bedding composition with calcium carbonate (CaCO ₃ ), and may be included in 3 to 12 parts by weight based on 100 parts by weight of the base resin . Here, when the content of the filler is less than 3 parts by weight, the effect of reducing manufacturing cost may be negligible, whereas when it exceeds 12 parts by weight, the mechanical properties, flexibility, and extrudability of the bedding composition may be deteriorated.

The other additives may further include a lubricant, an antioxidant, and a processing aid.

[Example]

1. Manufacturing example

Bedding compositions and bedding specimens were prepared according to the components and compounding ratios listed in Table 1 below.

Example Comparative example One 2 3 One 2 3 4 5 Suzy 1 100 85 100 80 100 100 Suzy 2 15 20 Suzy 3 100 Suzy 4 100 Flame retardant 240 270 260 270 240 240 220 290 Inhibitor 10 10 10 10 10 10 10 10 Filler 10 10 10 10 10 10 10 10

-Resin 1: Ethylene vinyl acetate (MI: 3; Tm: 70°C)

-Resin 2: Ethylene-butene copolymer (MI: 2.5 Tm: 78°C)

-Resin 3: Ethylene vinyl acetate (MI: 6; Tm: 62°C)

-Resin 4: Ethylene vinyl acetate (MI: 1.8; Tm: 85°C)

-Flame retardant: Silane coated magnesium hydroxide

-Inhibitor: zinc borate

-Filler: calcium carbonate

In addition, a cable specimen according to the structure shown in Table 2 was prepared.

1×240SQ 3×75SQ Example 4 Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Example 6 Example 7 Comparative Example 9 Comparative Example 10 Comparative Example 11 Conductor Al Al Internal peninsula Bando voltage output Semi-conductive extrusion Isolation XLPE XLPE External Peninsula Challenge Two pieces of semiconductive tape and semiconductive tape Two pieces of semiconductive tape and semiconductive tape Copper tape 1 piece 1 piece Glass tape 3 sheets none interposition none NDPP Insulation: Bedding
(Volume ratio) 1:1 1:3 1:0.5 1:3.5 1:1 1:1 1:2 1:0.5 1:3.5 1:1 Glass tape none 4 sheets none 4 sheets Sheath PO (LOI 42) PO (LOI 42)

2. Property evaluation

1) Oxygen Index (LOI) evaluation

Bedding specimens (width 6.5±0.5mm × thickness 3.0±0.25mm × length 70-150mm) formed from the compositions for bedding of Examples 1 to 3 and Comparative Examples 1 to 5 in accordance with the standard KS M ISO 4589-2 after combustion 3 Oxygen index (%) {=oxygen flow capacity/(oxygen flow capacity+nitrogen flow capacity)×100} was evaluated by measuring the flow rate of oxygen and nitrogen until combustion and extinction after 50 mm or more. The acceptance criteria must be 45% or higher.

2) Standard IEC 60332-3-22 Cat.A flame retardant evaluation

A flame of 70,000 BTU was applied to a cable specimen (7ℓ/m) having a bedding layer formed from the compositions for bedding of Examples 1 to 3 and Comparative Examples 1 to 5 and having a structure of 3 m and having the structure of FIG. 2 for 40 minutes. The post combustion length was measured. In addition, for the cable specimens of Examples 4 to 7 and Comparative Examples 6 to 11, the combustion length was measured through the same experiment. The acceptance standard is 2.5 m or less.

3) Evaluation of room temperature elongation

Room temperature elongation at a tensile speed of 250 mm/min for a bedding specimen (dumbbell-shaped specimen having a thickness of 4 mm) formed from the compositions for bedding of Examples 1 to 3 and Comparative Examples 1 to 5 according to the standard IEC 60811-1-1. Measured, the acceptance criteria should be at least 40%.

4) Flexibility evaluation

For the cable specimens of Examples 4 to 7 and Comparative Examples 6 to 11, the applied load was measured at a bending distance of 25 mm when a load was applied at a speed of 20 mm/min with respect to the center of the cable specimen through a 3-point bending test. Here, if the cable has the structure of FIG. 2 (single phase of the 240SQ conductor), the load should be 150 N or less, and if the cable has the structure of FIG. 3 (single phase of the 75SQ conductor), the load should be 200 N or less.

Evaluation of physical properties is as described in Tables 3 and 4 below.

Example Comparative example One 2 3 One 2 3 4 5 Oxygen index (%) 48 47.5 50 48 46 42.5 39 48 IEC 60332-3-22 (Cat.A) flame retardant Pass Pass Pass Pass Fail Fail Fail Pass Room temperature elongation (%) 50 42 44 35 87 15 63 38

Example 4 Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Example 6 Example 7 Comparative Example 9 Comparative Example 10 Comparative Example 11 Flame retardancy (m) 1.8 One Burnout 0.8 1.2 One 1.5 Burnout 0.6 2 Flexibility (N) 100 130 80 200 200 180 160 150 300 250

As shown in Tables 3 and 4, it was confirmed that the cable specimen having a bedding composition and a bedding layer formed from the bedding composition according to the present invention has excellent flame retardancy and flexibility.

On the other hand, the bedding composition of the comparative example and the cable specimen formed therefrom were found to have insufficient flame retardancy or insufficient flexibility.

Specifically, Example 1 satisfies both the flame retardancy and room temperature elongation of the cable specimen having a bedding layer formed from such a composition as satisfying the range of the composition ratio for the bedding composition of the present invention.

Example 2 reduced the content of resin 1 and increased the content of resin 2 than in example 1, and increased the flame retardant. Oxygen index and cable flame retardant properties according to IEC standards were satisfied, but room temperature elongation was measured to be slightly lower than in Example 1.

Example 3 further increased the flame retardant than Example 1. The oxygen index and the flame retardant properties of the cable were stably satisfied, and the elongation at room temperature was also measured at a level similar to that of Example 1 and Example 2.

Comparative Example 1 was evaluated as the content of Resin 1 and Resin 2 exceeding the scope of the present invention, which is less than the scope of the present invention, and satisfies properties such as flame retardancy, but was confirmed to significantly lower the elongation at room temperature.

Comparative Examples 2 and 3 were evaluated as Resin 3, which has a melt index exceeding the scope of the present invention, and Resin 4, which is less than the range of the present invention, respectively, instead of Resin 1, and has flame retardancy and/or standard IEC 60332-3- expressed as an oxygen index. 22 (Cat.A) was found to have insufficient flame retardancy, and in particular, Comparative Example 3 was confirmed to have significantly lowered the elongation at room temperature.

Comparative Example 4 was evaluated by the content of the flame retardant not exceeding the scope of the present invention, and it was confirmed that both the flame retardancy represented by the oxygen index and the flame retardancy of the standard IEC 60332-3-22 (Cat.A) were insufficient.

Comparative Example 5 was evaluated by the content of the flame retardant exceeding the scope of the present invention, and it was confirmed that the flame retardancy was excellent due to the excessive amount of the flame retardant, but the elongation at room temperature was significantly reduced.

In Examples 4 and 5, the bedding layer was formed from the composition for bedding of Example 1 in a single-core structure with one core, and the volume ratio between the bedding layer and the insulating layer was precisely controlled, thereby forming a glass taping layer between the bedding layer and the sheath layer. Despite not being applied, the flame retardant properties were satisfied and the flexibility was improved by 35% compared to the existing structure.

Examples 6 and 7 is a multi-core structure having three cores, a bedding layer is formed from the composition for bedding of Example 1, and the volume ratio between the bedding layer and the insulating layer is precisely controlled, thereby forming a glass taping layer between the bedding layer and the sheath layer. Despite not being applied, the flame retardant properties were satisfied, and the flexibility was improved by 28% compared to the existing structure.

In Comparative Examples 6 and 7, the bedding layer was formed from the bedding composition of Example 1 in a single-core structure with one core, but in Comparative Example 6, the volume ratio between the bedding layer and the insulating layer was significantly lower than the standard, whereas the flame retardancy was significantly reduced. In the case of 7, it was confirmed that the flexibility of the bedding layer and the insulating layer was significantly lower than the standard. On the other hand, in Comparative Example 8, it was confirmed that four glass tapes were applied between the bedding layer and the sheath layer to provide excellent flame retardancy, but to significantly reduce flexibility.

Comparative Examples 9 and 10 is a multi-core structure having three cores, the bedding layer is formed from the composition for bedding of Example 1, but in the case of Comparative Example 9, the volume ratio between the bedding layer and the insulating layer is significantly lower than the standard, while the flame retardancy is significantly reduced. In the case of 7, it was confirmed that the flexibility between the bedding layer and the insulating layer was significantly lower than the standard. On the other hand, in Comparative Example 11, four glass tapes were applied between the bedding layer and the sheathing layer, and excellent flame retardancy was confirmed, but flexibility was greatly reduced.

Although this specification has been described with reference to preferred embodiments of the present invention, those skilled in the art variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You can do it. Therefore, if the modified implementation basically includes the components of the claims of the present invention, it should be considered that all are included in the technical scope of the present invention.

10: conductor 20: inner semiconducting layer
30: insulating layer 40: outer semiconducting layer
50: metal shielding layer 60: glass taping layer
70: Bedding layer 70': Faithful bedding layer
80: outer sheath layer

Claims (25)

At least one core including a conductor, an inner semiconducting layer surrounding the conductor, an insulating layer surrounding the inner semiconducting layer, an outer semiconducting layer surrounding the insulating layer, and a metal shielding layer surrounding the outer semiconducting layer;
A bedding layer surrounding the at least one core and formed from a flame retardant composition; And
Wrapping the bedding layer and includes an outer sheath layer formed by extrusion of a sheath composition having an oxygen index of 35 to 47%,
The flame retardant composition includes a base resin and a flame retardant,
The volume ratio between the bedding layer and the insulating layer is 1:1 to 3:1,
Standard IEC 60332-3-22 Cat.A High flame retardant cable with a combustion length of 2.5 m or less when performing flame retardant evaluation. According to claim 1,
The bedding layer has an oxygen index of at least 45%, characterized in that the high flame retardant cable. According to claim 2,
High temperature flame retardant cable, characterized in that the room temperature elongation of the bedding layer is 40% or more. The method according to any one of claims 1 to 3,
If the core is one, characterized in that it further comprises a glass taping layer between the core and the bedding layer, high flame-retardant cable. The method according to any one of claims 1 to 3,
The base resin includes ethylene vinyl acetate resin, and the melt index of the ethylene vinyl acetate resin is 3 to 5, high flame retardant cable. The method of claim 5,
The base resin is characterized in that it further comprises an ethylene copolymer, high flame-retardant cable. The method of claim 5,
Based on 100 parts by weight of the base resin, the content of the ethylene vinyl acetate resin is 85 to 100 parts by weight, characterized in that the content of the ethylene copolymer is 0 to 15 parts by weight, high flame-retardant cable. The method of claim 5,
The ethylene vinyl acetate resin, characterized in that the content of the vinyl acetate monomer based on the total weight of 25 to 30% by weight, high flame-retardant cable. The method of claim 6,
The ethylene copolymer is characterized in that the melting point is 60 to 80 ℃, high flame-retardant cable. The method of claim 9,
The ethylene copolymer is characterized in that it comprises an ethylene-octene copolymer or ethylene-butene copolymer, or both, high flame retardant cable. The method according to any one of claims 1 to 3,
The flame retardant is characterized in that it comprises a metal hydroxide containing magnesium hydroxide or aluminum hydroxide or both, high flame retardant cable. The method of claim 11,
The magnesium hydroxide or the aluminum hydroxide is characterized in that the surface treatment with a hydrophobic surface treatment agent, high flame-retardant cable. The method of claim 11,
Based on 100 parts by weight of the base resin, the flame retardant content is characterized in that 240 to 280 parts by weight, high flame retardant cable. The method of claim 13,
The flame retardant composition, characterized in that it further comprises 5 to 15 parts by weight of at least one retardant selected from the group consisting of boric acid compounds, antimony compounds, and molybdenum compounds, based on 100 parts by weight of the base resin, high flame retardant cable. As a composition for high flame retardant bedding,
Base resin and flame retardant,
The base resin includes ethylene vinyl acetate resin,
The flame retardant comprises a metal hydroxide,
The ethylene vinyl acetate resin has a melt index of 3 to 5,
High flame retardant bedding composition with an oxygen index of at least 45%. The method of claim 15,
High temperature flame retardant bedding composition, characterized in that the room temperature elongation is 40% or more. The method of claim 16,
The base resin is characterized in that it further comprises an ethylene copolymer, high flame retardant bedding composition. The method according to any one of claims 15 to 17,
Based on 100 parts by weight of the base resin, the content of the ethylene vinyl acetate resin is 85 to 100 parts by weight, the content of the ethylene copolymer is 0 to 15 parts by weight, high flame retardant bedding composition. The method according to any one of claims 15 to 17,
The ethylene vinyl acetate resin is a composition for high flame retardant bedding, characterized in that the content of the vinyl acetate monomer is 25 to 30% by weight based on the total weight thereof. The method of claim 17,
The ethylene copolymer is characterized in that the melting point is 60 to 80 ℃, high flame retardant bedding composition. The method of claim 20,
The ethylene copolymer is characterized in that it comprises an ethylene-octene copolymer or ethylene-butene copolymer, or both, high flame retardant bedding composition. The method according to any one of claims 15 to 17,
The flame retardant is characterized in that it comprises a metal hydroxide containing magnesium hydroxide or aluminum hydroxide or both, high flame retardant bedding composition. The method of claim 22,
The magnesium hydroxide or the aluminum hydroxide is a surface treatment, characterized in that the surface treatment with a hydrophobic surface treatment agent. The method of claim 22,
Based on 100 parts by weight of the base resin, the flame retardant content is characterized in that 240 to 280 parts by weight, high flame retardant bedding composition. The method of claim 24,
Based on 100 parts by weight of the base resin, characterized in that it further comprises 5 to 15 parts by weight of one or more inhibitors selected from the group consisting of boric acid compounds, antimony compounds and molybdenum compounds, high flame retardant bedding composition.

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