KR20190121998A - Fire resistant cable - Google Patents

Abstract

The present invention relates to a fire resistant cable and, more specifically, to a fire resistant cable having the excellent fire resistance, flexibility, and mechanical strength, reducing a thickness and weight, increasing the productivity through cost reduction, and solving the problem that dielectric strength is reduced at early in the fire, which is five minutes before the formation of char, in a conventional fire resistant cable.

Description

Fire resistant cable

The present invention relates to a fireproof cable. Specifically, it has excellent fire resistance, flexibility and mechanical strength, and can reduce thickness and weight, and at the same time, increase productivity through cost reduction, and in particular, without inserting a mica tape applied in a conventional fire resistant cable. An extruded fire resistant cable for realizing performance.

In recent years, a major issue in the cable manufacturing industry has been to improve cable behavior and performance in extreme temperature conditions, particularly in the event of fire. For safety, it is essential to delay the spread of flames and to maximize the cable's ability to withstand flames.

The higher the fire-resistance of the cable, the longer the energizing time of the cable in the event of a fire, which extends the operating time of the sprinkler to delay the spread of the fire and the emergency exit indicator and elevator operating time. It can be extended to give people the time needed to evacuate people or to put in place proper extinguishing means.

The level of demand for fire resistance is gradually increasing. In particular, cable products used in land and marine plants and building infrastructure require higher fire resistance. Fire-fighting cables are needed to maintain the emergency power supply of core facilities, fire alarms, sprinklers, etc. for a minimum amount of time to escape and evacuate personnel in the event of a fire in a plant or building.

Such fire resistant cables generally achieve the fire resistance performance of the cable by applying mica tape between the conductor and the insulator and / or between the associated core and the sheath. However, when the mica tape is applied on a conductor or on an associated core, a difference in fire resistance may occur due to a taping quality such as a wrapping ratio of a taping or a taping tension, and thus, sufficient fire resistance may not be realized.

In addition, as the demand for the fire resistance characteristics of the cable increases, the mica content contained in the mica tape must be increased. Accordingly, the thickness of the mica tape is increased, thereby increasing the outer diameter of the cable, thereby decreasing the flexibility of the cable. The manufacturing cost of the cable may increase. In particular, there is a problem in that the working environment is poor, such as mica powder blowing due to the stripping of the mica tape during fireproof cable connection work.

Therefore, it is excellent in fire resistance, flexibility, mechanical strength, etc., and can reduce thickness and weight, and at the same time, increase productivity through cost reduction, and in particular, solve the problem of the installation environment issue of the conventional fireproof cable. In addition, there is an urgent need for a fireproof cable that can solve the problem of lowering the dielectric strength until about 5 minutes before fire occurs, that is, before char is formed.

An object of the present invention is to provide an extruded refractory cable that is excellent in fire resistance, flexibility, mechanical strength, etc., which can reduce thickness and weight, increase productivity through cost reduction, and which is not applied to mica tape. .

It is also an object of the present invention to provide a fireproof cable which can solve the problem of lowering the dielectric strength by about 5 minutes at the beginning of fire, that is, before char is formed.

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

A fire resistant cable, comprising: at least one core comprising a conductor, an insulation inner layer surrounding the conductor and an insulation outer layer surrounding the insulation inner layer; And a sheath layer covering the at least one core as a whole, wherein the insulating inner layer comprises refractory silicon, wherein the insulating outer layer is formed from an insulating composition comprising a base resin and a fire resistant agent.

Here, when the base resin includes at least one of ethylene propylene rubber (EPDM) and polyolefin elastomer (POE), and includes both the ethylene propylene rubber (EPDM) and polyolefin elastomer (POE), the compounding ratio is 9: 1 It is to provide a fire-resistant cable, characterized in that from 5: 5.

In addition, the refractory includes a mica powder, based on 100 parts by weight of the base resin, the content of the mica powder is characterized in that 100 to 160 parts by weight, provides a fire-resistant cable.

The mica powder includes natural mica powder and synthetic mica powder, and the blending ratio of the natural mica powder and the synthetic mica powder is 4: 6 to 6: 4.

On the other hand, the insulation composition further comprises a flame retardant adjuvant, the flame retardant adjuvant comprises one or more selected from the group consisting of antimony flame retardant adjuvant, boron zinc flame retardant adjuvant, aluminum hydroxide (ATH) and magnesium hydroxide (MDH). On the basis of 100 parts by weight of the base resin, the content of the flame retardant aid provides a fireproof cable, characterized in that 10 to 80 parts by weight.

Here, the flame retardant auxiliary agent provides a fire-resistant cable, characterized in that the surface is modified by the surface treatment agent.

In addition, the insulation composition further comprises at least one member selected from the group consisting of antioxidants, crosslinking agents and other additives.

The thickness of the insulation inner layer is 0.2 to 0.5 mm, and the thickness of the insulation outer layer is 0.4 to 0.7 mm.

On the other hand, the sheath layer provides a fire resistant cable, characterized in that it comprises an inner sheath layer, an outer layer and an outer sheath layer.

The fire resistant cable according to the present invention improves fire resistance characteristics, flexibility, mechanical strength, etc. of the cable through a specific formulation of the insulating composition forming the insulating layer, and reduces the thickness and weight of the cable because no separate mica tape is applied. At the same time, it shows an excellent effect of reducing the manufacturing cost.

In addition, the fire resistant cable according to the present invention has an excellent effect that can solve the problem that the insulation strength is reduced by about 5 minutes before the start of the fire, that is before the formation of char (char) through the structure of a specific insulating layer.

1 is a schematic cross-sectional view of a three-phase fireproof cable according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 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 disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. Like numbers refer to like elements throughout.

1 is a schematic cross-sectional view of a three-phase fireproof cable according to an embodiment of the present invention.

As shown in FIG. 1, the fire resistant cable 100 according to the present invention includes a conductor 111, an insulation inner layer 112 surrounding the conductor 111, and an insulation outer layer 113 surrounding the insulation inner layer 112. It may include one or more cores 110, sheath layer surrounding the one or more cores 110 as a whole.

The conductor 111 is made of a conductive material such as copper (Cu), aluminum (Al), so that a conductor such as Class 2 or Class 5 that provides a current flow path and satisfies the IEC 60228 standard may be used.

The insulating inner layer 112 has a function of suppressing a drop in dielectric strength until about 5 minutes before char is formed from the insulating outer layer 113 at the beginning of a fire, and includes refractory silicon. It may be formed by extrusion of the insulating composition or the like. The refractory silicon may include, for example, silicon to which refractory fillers such as magnesium hydroxide (MDH) and aluminum hydroxide (ATH) are added.

In addition, the insulating outer layer 113 is a configuration for maintaining the insulation performance of the cable by forming a char (char) in the event of a fire, it may be formed by extrusion of the insulating composition containing a base resin and additives. .

The base resin is a polyolefin resin such as polyethylene (PE), polypropylene (PP), ethylene vinyl acetate (EVA), ethylene propylene dien monomer (EPDM), high ethylene propylene rubber (EPR) Polyvinyl chloride (PVC), etc. may be optionally included, and preferably, may include ethylene propylene dien monomer (EPDM) having low specific gravity, good mechanical properties, and excellent heat resistance and chemical resistance.

The base resin may further comprise a polyolefin elastomer (POE). The polyolefin elastomer (POE) may further improve elongation, heat resistance, and the like of the insulating outer layer 113.

When the base resin includes both ethylene propylene rubber (EPDM) and polyolefin elastomer (POE), the mixing ratio of the ethylene propylene rubber (EPDM) and polyolefin elastomer (POE) may be 9: 1 to 5: 5. When the compounding ratio is less than 5: 5, mechanical properties, fire resistance, and the like of the insulating outer layer 113 may be lowered.

The additive may include a fireproofing agent and a flame retardant aid. Here, the refractory agent may include, for example, mica powder. The mica powder functions to maintain the insulation performance of the cable for a predetermined time by forming a hard char in the process of burning the insulating outer layer 113 in the event of a fire.

The mica powder may have a particle diameter of 2 to 12 μm (type F) or 3 to 25 μm (type D). The particle diameter of the mica powder does not directly affect the fire resistance performance, but if the particle diameter is too small, there is a problem in that it is too difficult to control when mixing, and the mixing is poor.

The mica powder may include both natural mica powder and synthetic mica powder. The natural mica powders are relatively good in fire resistance but relatively deteriorate in mechanical properties, while the synthetic mica powders are relatively low in mechanical properties but relatively inferior in fire resistance. It can be used in combination from 6 to 6: 4.

Based on 100 parts by weight of the base resin, the content of the mica powder may be 100 to 160 parts by weight, preferably 110 to 160 parts by weight. When the content of the mica powder is less than 100 parts by weight, the fire resistance performance of the insulating outer layer 113 may be significantly lowered, whereas when the content of the mica powder is greater than 160 parts by weight, compatibility with the base resin, extrudability of the insulating composition, the Water resistance and the like of the insulating outer layer 113 may be greatly reduced.

The flame retardant aid improves the mechanical strength of char formed when the insulation outer layer 113 is burned, and in particular, improves flame retardancy to secure time for char formation when burning the insulation outer layer 113. To perform a function to, for example, may include antimony flame retardant aids, metal hydroxide flame retardant aids such as aluminum hydroxide (ATH), magnesium hydroxide (MDH) or zinc boron flame retardant aids.

The flame retardant aid may be surface modified with a surface treatment agent. When the surface of the flame retardant aid is modified, compatibility with the base resin, that is, dispersibility in the base resin is improved, thereby improving mechanical properties of the insulating outer layer 113 and improving the water resistance of the insulating outer layer 113. It may be further improved, but the fire resistance may be slightly lowered.

Based on 100 parts by weight of the base resin, the content of the flame retardant aid may be 10 to 80 parts by weight, preferably 60 to 80 parts by weight. When the content of the flame retardant aid is less than 10 parts by weight, the mechanical strength of the char formed when the insulation outer layer 113 is burned is so low that it can be easily broken even at a small impact. The water resistance of the outer layer 113 may be lowered, and in particular, a char formed as the insulating outer layer 113 burns may be broken by itself.

The additive may further include an antioxidant, a crosslinking agent, other additives, and the like, in addition to the fireproofing agent and the flame retardant aid. The antioxidant may perform a function of preventing deterioration due to oxidation of the base resin, and may be included in an amount of 3 to 8 parts by weight, preferably 5.5 to 8 parts by weight based on 100 parts by weight of the base resin.

The crosslinking agent may be different according to the crosslinking method of the base resin. For example, when the crosslinking method of the base resin is chemical crosslinking, the crosslinking agent is dicumyl peroxide, benzoyl peroxide, lauryl peroxide, t-butyl. Organic peroxide crosslinking agents such as cumyl peroxide, di (t-butyl peroxy isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butyl peroxy) hexane and di-t-butyl peroxide If the crosslinking method is water crosslinking, the crosslinking agent may be a silane-based crosslinking agent.

The amount of the crosslinking agent may be 5 to 7 parts by weight based on 100 parts by weight of the base resin. When the content of the crosslinking agent is less than 5 parts by weight, the degree of crosslinking of the base resin may be lowered, and the mechanical properties of the insulating outer layer 113 may be lowered. long-term extrudability may be impaired, such as scorch).

The other additives may include oils, lubricants, and the like to further improve uniform mixing of the components of the insulating composition forming the insulating outer layer 113, extrudability, moldability, etc. of the insulating outer layer 113. . Based on 100 parts by weight of the base resin, the amount of oil may be 10 to 13 parts by weight, and the amount of the lubricant may be 6 to 8 parts by weight.

In the present invention, the thickness of the insulating inner layer 112 is about 0.2 to 0.5 mm, the thickness of the insulating outer layer 113 may be adjusted to about 0.4 to 0.7 mm.

By the above-described configuration, the fire resistant cable of the present invention has improved fire resistance, flexibility, mechanical strength, and the like, and thus, there is no need to apply a separate mica tape, thereby reducing the thickness and weight of the cable and at the same time reducing the manufacturing cost. You can. In particular, the fire resistant cable of the present invention can secure the dielectric strength up to about 5 minutes at the beginning of the fire, that is, before the char is formed by the double-layer structure of the insulating inner layer 112 and the insulating outer layer 113.

In the present invention, the sheath layer may include an inner sheath layer 120, an outer layer 130, an outer sheath layer 140, and the like.

Here, the inner sheath layer 120 has a high impact resistance polyvinyl chloride (PVC), polychloroprene rubber (CR), chlorosulfonated polyethylene (CSPE), chlorinated polyethylene (chlorinated polyethylene; CPE), ethylene vinyl acetate (EVA), or a mixture thereof, and the like.

The outer layer 130 is formed on the outer side of the inner sheath layer 120. The outer layer 130 is made of a metal material such as copper, aluminum, iron and copper alloys, aluminum alloys, metal braided metal tape, It may be in the form of a metal wire or the like.

In addition, an outer sheath layer 140 is formed outside the outer layer 130, and the outer sheath layer 140, like the inner sheath layer 120, has a high impact resistance polyvinyl chloride (PVC). ), Polychloroprene rubber (CR), chlorosulfonated polyethylene (CSPE), chlorinated polyethylene (CPE), ethylene vinyl acetate (EVA) or mixtures thereof It can be formed by extrusion, etc., and serves to protect the cable from external impact or corrosion.

The structures of the inner sheath layer 120, the outer layer 130, and the outer sheath layer 140 may vary depending on the purpose of the cable. In addition, as shown in FIG. 1, in the case of a multi-core cable, a plurality of cores 110 are fed together and a twist is applied at a predetermined pitch, and then the filler 150 is applied to the gaps therebetween. The cable may be manufactured by forming the sheath layer 120, the outer layer 130, the outer sheath layer 140, and the like.

EXAMPLE

1. Manufacturing Example

Insulation compositions were prepared with the components and contents listed in Table 1 below, and insulation specimens were prepared.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Resin 1 100 100 50 50 100 100 100 100 Resin 2 50 50 Mica 1 85 80 50 50 25 50 80 Mica 2 25 80 50 70 75 50 80 100 Flame Retardant Supplements 1 30 30 Flame retardant supplements 2 60 40 60 60 30 30 90 Crosslinking agent 7 5 5 5 5 5 5 5 Antioxidant 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 Oils 13 13 13 13 13 13 13 13 Other additives 7 7.5 7.5 7.5 7.5 7.5 7.5 7.5

Resin 1: Ethylene Propylene Rubber (EPDM)

Resin 2: Polyolefin Elastomer (POE)

Mica 1: Natural Mica Powder

Mica 2: Synthetic Mica Powder

-Flame Retardant Aid 1: Antimony flame retardant without surface treatment

-Flame retardant aid 2: Surface-treated antimony flame retardant aid

2. Property evaluation

1) Evaluation of tensile strength and elongation at room temperature

EXAMPLES AND COMPARATIVE EXAMPLES Five dumbbell presses each having a width of 4 mm were manufactured, and then the tensile strength was 20 mm and the tensile speed was 250 mm / min using the Universal Testing Machine according to IEC 60811-1-1. And elongation was measured, and the average of three specimens except the lowest value and the maximum value was calculated.

2) heat resistance evaluation

EXAMPLES AND COMPARATIVE EXAMPLES Each press specimen was prepared five times and stored in an oven at 136 ° C for 168 hours in accordance with the standard IEC 60092-351. And the tensile residual ratio and the elongation residual ratio were calculated based on the elongation rate.

3) Water resistance evaluation

The immersion capacitance change rate was evaluated by substituting the immersion volume resistance change rate. Specifically, the press specimens of 100 × 100 × 1 mm of each of Examples and Comparative Examples were prepared, and after 1 week / 2 weeks of storage in a 50 ° C. constant temperature water bath, they were removed and only surface water was removed. The resistance to the volume was measured by applying a voltage of and compared with before immersion.

4) Fire resistance rating

The fire resistance rating was evaluated by replacing the insulator breakdown voltage test (BDV). Specifically, the press specimens of 50 × 50 × 1 mm of each of the Examples and Comparative Examples were prepared and placed in a 830 ° C. high temperature furnace for 30 minutes at a high temperature while applying 0.25 to 1 kV voltage in real time to the top and bottom surfaces of the sheet. The leakage current was measured and insulation performance evaluation was performed.

The results of the physical property evaluation are as shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Room temperature tensile strength
(kgf / ㎡) 0.901 0.497 1.163 1.123 1.024 1.011 0.618 0.886 Room temperature elongation
(%) 297.24 67.72 547.03 154.13 521.29 522.74 291.82 491.1 Heating tensile strength
(kgf / ㎡) 146.39 174.04 116.08 129.48 79.88 78.54 126.38 104.97 Heating elongation
(%) 44.9 70.84 25.43 50.54 64.91 61.16 29.92 75.18 Volume resistance
(Ωcm) Before immersion 2.8365E + 15 1.8382E + 15 3.4946E + 15 4.661E + 15 4.9783E + 15 3.4986E + 15 2.782E + 15 2.54E + 15 Day 1 3.349E + 15 1.335E + 13 5.0024E + 13 1.4679E + 13 3.5541E + 14 3.7621E + 14 2.4548E + 13 3.18E + 14 Week 1 4.7456E + 14 1.5003E + 13 3.5421E + 14 2.121E + 13 5.0846E + 14 3.7844E + 14 1.6796E + 13 7.45E + 14 2nd week 7.4717E + 14 1.1116E + 13 1.50E + 14 7.6365E + 13 4.6334E + 14 5.5418E + 14 1.17E + 13 1.54E + 15 Fireproof So
Great Great Great Great Great Great Bad Bad

As shown in Table 2, the insulating outer layers of Examples 1 to 6 according to the present invention are excellent in mechanical properties, heat resistance, water resistance, fire resistance, and the like, and in particular, the insulating outer layer of Example 1 does not swell at all and the insulating specimen does not appear in appearance. Attitude was very good and the strength was the strongest and the initial flexibility was not broken even when the char was formed.

In addition, although the insulating outer layer of Example 2 had a fairly hard char, the surface portion was slightly thick, and the insulating outer layers of Examples 3 and 5 had a hard char and had a good appearance, respectively. It was slightly peeled off, and the insulating outer layer of Example 4 had good char strength, no cracking, and the surface was smooth but had a slight lack of water resistance, and the insulating outer layer of Example 6 had a slight char strength and no cracking, but the surface was slightly peeled off and room temperature Elongation rate was too high and heating elongation rate fell.

On the other hand, the insulation outer layer of Comparative Example 1 was not applied to the flame retardant aid, it was swelling only to maintain the shape, but the strength was too weak to implement fire resistance, and the insulation outer layer of Comparative Example 2 was too easy to crack the high temperature due to the excessive flame retardant content is too high Fire resistance could not be achieved due to self-cracking at.

Although described above with reference to an embodiment of the present invention, those skilled in the art to various modifications and changes to the present invention without departing from the spirit and scope of the invention described in the claims described below You can do it. Therefore, it should be seen that all modifications included in the technical scope of the present invention are basically included in the scope of the claims of the present invention.

100: fireproof cable
110: cable core 111: conductor
112: insulation inner layer 113: insulation outer layer
120: inner sheath layer 130: outer layer
140: outer sheath layer 150: filler

Claims (9)

As fireproof cable,
At least one core comprising a conductor, an insulation inner layer surrounding the conductor, and an insulation outer layer surrounding the insulation inner layer; And
A sheath layer surrounding the at least one core as a whole;
The insulating inner layer comprises refractory silicon,
And the insulating outer layer is formed from an insulating composition comprising a base resin and a fire resistant agent. The method of claim 1,
The base resin includes at least one of ethylene propylene rubber (EPDM) and polyolefin elastomer (POE),
When both the ethylene propylene rubber (EPDM) and polyolefin elastomer (POE) is included, the compounding ratio is 9: 1 to 5: 5, characterized in that the fire-resistant cable. The method of claim 2,
The fireproofing agent comprises mica powder,
Based on 100 parts by weight of the base resin, the content of the mica powder is characterized in that 100 to 160 parts by weight, fire-resistant cable. The method of claim 3,
The mica powder includes natural mica powder and synthetic mica powder,
The blending ratio of the natural mica powder and the synthetic mica powder is characterized in that 4: 6 to 6: 4, fire-resistant cable. The method according to any one of claims 1 to 4,
The insulation composition further comprises a flame retardant aid,
The flame retardant adjuvant includes at least one selected from the group consisting of antimony flame retardant adjuvant, boron zinc flame retardant adjuvant, aluminum hydroxide (ATH) and magnesium hydroxide (MDH),
Based on 100 parts by weight of the base resin, the content of the flame retardant aid is characterized in that 10 to 80 parts by weight, fire-resistant cable. The method according to any one of claims 1 to 4,
The flame retardant auxiliary agent is characterized in that the surface is modified by a surface treatment agent, fire-resistant cable. The method according to any one of claims 1 to 4,
And the insulation composition further comprises at least one member selected from the group consisting of antioxidants, crosslinkers and other additives. The method according to any one of claims 1 to 4,
The fireproof cable, characterized in that the thickness of the insulation inner layer is 0.2 to 0.5 mm, the thickness of the insulation outer layer is 0.4 to 0.7 mm. The method according to any one of claims 1 to 4,
Wherein the sheath layer comprises an inner sheath layer, an outer layer and an outer sheath layer.

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