KR20210054207A - Halogen-free resin composition having high flame retardancy and low emitting smoke and UTP cable comprising a sheath formed from the same - Google Patents

Abstract

The present invention relates to a halogen-free resin composition having high flame retardancy and emitting low smoke for forming a sheath layer of a UTP cable, and to a UTP cable comprising a sheath layer formed therefrom. Specifically, the present invention relates to a halogen-free resin composition, which satisfies C-grade or higher high flame retardancy based on recently applied construction products regulation (CPR) standards in Europe and properties of emitting low smoke, and at the same time, can reduce manufacturing costs, and to a sheath layer formed therefrom.

Description

UTP cable comprising a high flame retardant and low smoke non-halogen-based resin composition and a sheath layer formed therefrom {Halogen-free resin composition having high flame retardancy and low emitting smoke and UTP cable comprising a sheath formed from the same}

The present invention relates to a UTP cable comprising a high flame retardant and low smoke non-halogen resin composition for forming a sheath layer of a UTP cable, and a sheath layer formed therefrom. Specifically, the present invention is a non-halogen-based resin composition that can reduce manufacturing costs while satisfying high flame retardancy and low smoke performance of grade C or higher based on the CPR (Construction Products Regulation) standard recently applied in Europe, and a sheath layer formed therefrom. It relates to a UTP cable comprising a.

UTP (UTP) cable is an abbreviation of unshielded twisted pair, and is also referred to as unshielded pair cable or unshielded twisted pair cable. The most common form of a UTP cable is a copper wire, which is used as a signal line connecting a general telephone line or a LAN (local area network) environment.

The outer surface of the TV cable is covered with a sheath material, and the sheath layer made of such a sheath material is exposed so as to directly contact the outside. In the case of a plenum class UTP cable, since it is used for laying in an environment without a duct, excessive smoke is generated when a fire occurs in a space in which the cable or the like is installed.

Therefore, in the case of a plenum class UTP cable, in the case of a material having strong combustibility, it can be used as a passage for fire spreading, so a material having low smoke resistance and high flame retardancy should be used. However, in the case of insulation and sheath materials used as conventional plenum grades, the flue gas toxicity index required by the new standard CPR grade cannot be satisfied. Polyolefin resin is applied as a material with relatively low combustion gas hazard.In particular, in the case of a UTP cable to which a polyolefin sheath is applied, it generally satisfies CM and CMX flame retardant, and various flame retardants based on metal hydroxides are applied to satisfy this. According to the UL 1685 standard, CM flame retardancy is evaluated by the combustion length after applying a flame for 20 minutes with a heat value of 21 kW.

However, in the case of the recently applied CPR (Construction Products Regulation) certification, the flame retardant evaluation method is similar, but a certain level of combustion length, maximum heat release rate, total heat release rate, and flame spread rate are required, and additional smoke index is required. do.

On the other hand, in the case of the conventional UTP cable to which the polyolefin sheath satisfies CM flame retardant, it has been confirmed that it is at the D grade level based on the CPR standard, and a new low smoke high flame retardant that satisfies the higher grade C grade or higher while reducing the manufacturing cost. Development of sheath material is urgent.

The present invention provides a UTP cable including a non-halogen resin composition capable of reducing manufacturing cost while satisfying high flame retardancy and low smoke resistance of C grade or higher based on CPR (Construction Products Regulation) standards, and a sheath layer formed therefrom. It aims to do.

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

As a non-halogen resin composition for forming a sheath layer of a UTP cable, an ethylene vinyl acetate (EVA) resin having a vinyl acetate content of 20 to 40% by weight, a polyolefin elastomer resin, and a linear low density grafted with a polar group Including a base resin including a polyethylene resin and a non-halogen-based flame retardant, and the non-halogen-based flame retardant includes a flame retardant including aluminum hydroxide and magnesium hydroxide, and a flame retardant aid including a silicic acid-based flame retardant, an antimony-based flame retardant, and a zinc-based flame retardant. And, the UTP cable including the sheath layer formed from the non-halogen-based resin composition satisfies the C grade or higher of the CPR (Construction Products Regulation) certification, and provides a non-halogen-based resin composition.

Here, based on 100 parts by weight of the base resin, the content of the ethylene vinyl acetate (EVA) resin is 40 to 65 parts by weight, the content of the polyolefin elastomer resin is 15 to 35 parts by weight, the linear low density polyethylene grafted with the polar group It provides a non-halogen resin composition, characterized in that the content of the resin is 15 to 35 parts by weight.

In addition, based on 100 parts by weight of the base resin, the content of aluminum hydroxide as the flame retardant is 45 to 65 parts by weight, the content of natural magnesium hydroxide in magnesium hydroxide as the flame retardant is 30 to 50 parts by weight, and the content of synthetic magnesium hydroxide is 115 To 135 parts by weight, the content of the silicic acid-based flame retardant is 5 to 15 parts by weight, the content of the antimony-based flame retardant is 10 to 20 parts by weight, and the content of the zinc-based flame retardant is 5 to 15 parts by weight, non-halogen It provides a system resin composition.

Furthermore, the polyolefin elastomer resin provides a non-halogen resin composition, characterized in that it contains an ethylene octene copolymer.

Meanwhile, the silicic acid-based flame retardant provides a non-halogen-based resin composition, characterized in that it contains a hydrous magnesium silicate.

In addition, the antimony-based flame retardant provides a non-halogen-based resin composition, characterized in that it contains antimony trioxide.

In addition, the zinc-based flame retardant provides a non-halogen-based resin composition, characterized in that it contains zinc borate.

On the other hand, it provides a UTP (UTP) cable including a sheath layer formed from the non-halogen resin composition.

Despite the fact that the non-halogen resin composition according to the present invention secures the mechanical strength required in the sheath layer of the UTP cable and satisfies the high flame retardancy, low smoke and low toxicity of the CPR (Construction Products Regulation) standard, And it shows an excellent effect that can reduce the manufacturing cost.

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 content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

The present invention relates to a high flame retardant and low smoke non-halogen resin composition for forming a sheath layer of a UTP cable.

The non-halogen-based resin composition according to the present invention includes a polyolefin-based base resin and a flame retardant, and may further include other additives such as antioxidants and lubricants. Here, the polyolefin-based base resin may include an ethylene vinyl acetate (EVA) resin, a polyolefin elastomer resin, and a linear low-density polyethylene resin grafted with a polar group such as maleic anhydride, glycidyl methacrylate, etc. have.

Since the polyolefin-based base resin is formed by blending of the above-described specific resin, mechanical properties and flame retardancy required in the sheath layer of the UTP cable can be implemented, and sufficient filler loading properties for the flame retardant can be implemented.

Specifically, the ethylene vinyl acetate (EVA) resin has a vinyl acetate content of 20 to 40% by weight, and the polyolefin elastomer resin may include an ethylene octene copolymer.

On the other hand, the linear low-density polyethylene resin grafted with the polar group improves the filler loading capacity of the flame retardant to the base resin, so that the flame retardancy of the non-halogen resin composition is compared to other compositions containing the same amount of flame retardant. At the same time, by improving the dispersibility of the flame retardant in the base resin, it is possible to suppress a decrease in mechanical properties, extrudability, and the like of the non-halogen-based resin composition due to aggregation of the flame retardant.

In addition, when the vinyl acetate content in the vinyl acetate (EVA) resin is more than 40% by weight, the flame retardancy of the non-halogen-based resin composition is improved, while the mechanical strength is lowered. Conversely, when the content is less than 20% by weight, the non-halogen-based resin The mechanical strength of the composition is improved while the flame retardancy is lowered.

Further, based on 100 parts by weight of the polyolefin-based base resin, the content of the ethylene vinyl acetate (EVA) resin is 40 to 60 parts by weight, the content of the polyolefin elastomer resin is 15 to 35 parts by weight, and the polar group is grafted. The content of the linear low density polyethylene resin may be 15 to 35 parts by weight.

Here, when the content of the ethylene vinyl acetate (EVA) resin is less than 40 parts by weight, the flame retardancy of the non-halogen-based resin composition decreases, whereas when it exceeds 60 parts by weight, the strength of the non-halogen-based resin composition may be significantly reduced. have.

In addition, when the content of the polyolefin elastomer is less than 15 parts by weight, the elongation of the non-halogen-based resin composition may be lowered, whereas when it is more than 35 parts by weight, the mechanical strength of the non-halogen-based resin composition may be significantly reduced.

And, when the content of the linear low-density polyethylene resin grafted with the polar group is less than 15 parts by weight, the non-halogen-based resin composition has flame retardancy, mechanical strength, elongation, and extrudability due to a decrease in compatibility with additives such as the base resin and a flame retardant. On the other hand, if it exceeds 35 parts by weight, the content of the ethylene vinyl acetate (EVA) resin or the polyolefin elastomer resin is relatively reduced, so that the flame retardancy or elongation of the non-halogen resin composition is selectively greatly reduced. Can be.

The flame retardant includes a non-halogen-based flame retardant, and specifically, a metal hydroxide such as aluminum hydroxide and magnesium hydroxide, and a silicic acid-based flame retardant, preferably a hydrous magnesium silicate, an antimony-based flame retardant, preferably an antimony trioxide and a zinc-based flame retardant, preferably May include a flame retardant aid containing zinc borate.

The flame retardant including aluminum hydroxide, magnesium hydroxide, etc., mainly improves the flame retardant, fire resistance, and suppression properties of the non-halogen-based resin composition when a fire occurs.In particular, aluminum hydroxide and magnesium hydroxide are respectively at about 200°C or higher and about 340°C or higher. Flame-retardant, fire-retardant and suppressed by the ceramic, which not only lowers the ambient temperature by causing an endothermic reaction that decomposes into metal oxide, that is, ceramic and water, but also has improved strength and excellent water resistance, even under severe conditions. It can perform a function that allows the properties to be maintained.

2Al(OH) ₃ -> Al ₂ O ₃ + 3H2O-298kJ/mol at ≥200℃

Mg(OH) ₂ -> MgO + H ₂ O-330kJ/mol at ≥340℃

Here, the magnesium hydroxide may include both hydrotalc-based natural magnesium hydroxide and synthetic magnesium hydroxide, and the hydrotalc-based natural magnesium hydroxide has a non-uniform particle size and contains impurities compared to synthetic magnesium hydroxide, but its flame retardancy is somewhat low, but the price is low. Due to its inexpensive advantage, it is possible to minimize the manufacturing cost while implementing the desired flame retardancy by mixing natural magnesium hydroxide and containing magnesium hydroxide in an appropriate ratio. In addition, the aluminum hydroxide and the magnesium hydroxide may or may not be surface treated with a hydrophobic surface treatment agent such as vinylsilane.

Here, in natural magnesium hydroxide, _{the total content of MgO and Mg(OH) 2} is 63.5 to 65.5 wt% based on the total weight, and the average particle size (D ₅₀ ) is 3.0 to 5. 0 µm, whereas the synthetic magnesium hydroxide is The total content of Mg(OH) ₂ may be 99.8 wt% or more based on the total weight, and the average particle size (D ₅₀ ) may be 1.6 to 2.0 µm. The average particle size (D ₅₀ ) is a value corresponding to 50% of the maximum diameter of the particle, and the diameter of the particle refers to the diameter of a sphere converted to have the same volume as the particle.

Usually, in order to improve compatibility with the base resin, the surface of the additive having a hydrophilic surface may be surface-treated with hydrophobicity, but when the surfaces of the aluminum hydroxide and magnesium hydroxide are treated with hydrophobicity, the flame retardancy of the non-halogen-based resin composition This can be finely degraded.

Meanwhile, since the surfaces of the aluminum hydroxide and magnesium hydroxide are not surface-treated with other materials, the compatibility of the aluminum hydroxide and magnesium hydroxide and the base resin is reduced. It can be compensated for by improving loading.

Melamine cyanurate, which has been generally used as a flame retardant aid in the past, has a problem of generating corrosive combustion gases including acid after combustion, so it is replaced with the above-described silicic acid-based flame retardant, antimony-based flame retardant, and zinc-based flame retardant. However, the antimony-based flame retardant has a problem of high cost, and thus the decrease in flame retardancy while controlling its content can be solved by a combination of a silicic acid-based flame retardant and a zinc-based flame retardant, and a specific combination of the base resin described above.

Specifically, the silicate-based flame retardant including the hydrous magnesium silicate, etc., assists the flame retardant and fire resistance properties such as lowering the ambient temperature when a fire occurs, and at the same time maintains its shape even when the sheath layer is burned, thereby preventing the flame from penetrating into the interior. It can perform the function of suppressing as much as possible.

In addition, the antimony-based flame retardant including antimony trioxide, etc., exhibits a flame retardant synergistic effect together with the metal hydroxide-based flame retardant when a fire occurs, so that the flame retardant and fire resistance properties of the non-halogen-based resin composition such as lowering the ambient temperature can be maintained. Auxiliary flame retardant, fire resistance and suppression properties can be implemented, and the zinc-based flame retardant including the zinc borate or the like forms a char when a fire occurs, and a sheath layer formed from the non-halogen-based resin composition and a UTP cable comprising the same By maintaining the structure of the auxiliary flame retardant, fire resistance and suppression properties can be implemented.

The flame retardant comprises 45 to 65 parts by weight of aluminum hydroxide, 145 to 185 parts by weight of magnesium hydroxide, specifically 30 to 50 parts by weight of natural magnesium hydroxide, and 115 to 135 parts by weight of synthetic magnesium hydroxide based on 100 parts by weight of the polyolefin-based base resin. The flame retardant aid may include 5 to 15 parts by weight of a silicic acid-based flame retardant, 10 to 20 parts by weight of the antimony-based flame retardant, and 5 to 15 parts by weight of the zinc-based flame retardant based on 100 parts by weight of the polyolefin base resin.

By precisely controlling the content of the flame retardant and the flame retardant auxiliary as described above, it is possible to minimize the manufacturing cost of the non-halogen-based resin composition, and at the same time realize high flame retardancy and low smoke retardancy of level C or higher of CPR (Construction Products Regulation) certification. In order to implement such high flame retardancy and low smoke resistance in a UTP cable including a sheath layer formed from such a sheath composition, the thickness of the sheath layer may be 0.6 to 0.7 mm.

[Example]

1. Manufacturing example

A non-halogen resin composition and a sheath layer specimen formed therefrom and a UTP cable specimen were prepared with the components and contents as shown in Table 1 below. The units of the content listed in Table 1 below are parts by weight.

Example Comparative example One 2 One 2 3 4 5 6 Suzy 1 50 55 65 35 40 55 50 50 Suzy2 25 25 45 10 25 25 25 Suzy 3 25 20 35 20 50 20 25 25 Flame retardant 1 55 45 55 55 55 45 80 65 Flame retardant 2 40 50 40 40 40 100 50 40 Flame retardant 3 125 120 125 125 125 70 90 125 Flame retardant 4 10 15 10 10 10 15 10 10 Flame retardant 5 10 10 10 10 10 10 10 10 Flame retardant 6 10 10 10 10 10 10 10 Antioxidant
And other additives 12 12 12 12 12 12 12 12 Total content 362 362 362 362 362 362 362 362

-Resin 1: Ethylene vinyl acetate (EVA) resin (vinyl acetate content 28% by weight)

-Resin 2: Polyolefin elastomer resin (ethylene octene copolymer)

-Resin 3: Linear low-density polyethylene resin grafted with maleic anhydride

-Flame retardant 1: Aluminum hydroxide

-Flame retardant 2: Hydrotalcite-based natural magnesium hydroxide coated with silane

-Flame retardant 3: Synthetic magnesium hydroxide coated with silane

-Flame retardant 4: Antimony trioxide

-Flame retardant 5: zinc borate

-Flame retardant 6: hydrous magnesium silicate

-Other additives: lubricant

2. Property evaluation

(1) Room temperature tensile strength and elongation evaluation

Tensile strength and elongation were measured for each of the sheath layer specimens of Examples and Comparative Examples according to standard UL444 (evaluation rate is 200 mm/min), and the tensile strength should be 0.92 kgf/mm2 or higher and the elongation rate should be 100% or higher.

(2) Evaluation of tensile strength and elongation after heating

Tensile residual and elongation residual based on tensile strength and elongation at room temperature when the sheath layer specimens of Examples and Comparative Examples were left in an oven at 100° C. for 168 hours and then measured for tensile strength and elongation (evaluation rate is 200 mm/min). These should be at least 75% and at least 50%, respectively.

(3) Evaluation of flame retardancy and smoke resistance

① Measurement of combustion length

According to the standard EN 50399, the combustion length of the cable propagated vertically after applying a flame for 20 minutes after applying a flame to each of the UTP cable specimens in the Example and Comparative Example was measured. It must be 1.5 m or less, and the combustion length must be 2.0 m or less to satisfy CPR C grade.

② Peak Heat Release Rate (PHRR)

According to the standard EN 50399, a flame is applied to each of the TV cable specimens in Examples and Comparative Examples for 20 minutes to collect smoke generated during combustion and measure the content of consumed oxygen, released oxygen monoxide, and carbon dioxide, and smoke The heat release rate was calculated comprehensively by measuring the temperature, flow rate, pressure difference, etc., and the maximum value was selected. At this time, the maximum heat release rate must be 30 kW or less to satisfy the CPR B class, and the maximum heat release rate must be 60 kW or less to satisfy the CPR C class.

③ Total Heat Release (THR)

It was calculated by integrating the heat release rate (HRR) values expressed as a function of time, and the total heat release rate to satisfy the CPR B grade is 15 MJ or less, and the total heat release rate to satisfy the CPR C grade must be 30 MJ or less.

④ Fire Growth Rate (FIGRA)

The flame propagation speed was obtained by dividing the maximum heat release rate by the time at which the heat release rate became the maximum after applying the flame to the cable specimen. Flame propagation speed to satisfy CPR B class should be 150W/s or less, and flame propagation speed to satisfy CPR C class must be 300W/s or less.

⑤ Total Smoke Production (TSP), Peak Smoke Production Rate (SPR), and Spark Combustion Test (Drip)

According to the standard EN 50399, the total amount of smoke was measured after applying a flame for 20 minutes after applying a flame to each of the UTP cable specimens in the Examples and Comparative Examples, and the maximum smoke rate was calculated from the amount of smoke per hour, and separated from the cable. The burning time of the resulting sparks was measured. The total amount of smoke should be 50 ㎡ or less, the maximum smoke rate should be 0.25 ㎡/s or less, and the burning time of sparks should be 10 seconds or less.

⑥ Combustion gas harmfulness

According to the standard EN 50267-2,3, the sheath layer specimens of each of the Examples and Comparative Examples were heated in a tube furnace of 935° C. or higher for 30 minutes, and then immersed in a distilled water container, and then pH and conductivity were measured. The pH should be 4.3 or higher and the conductivity should be 2.5 μS/mm or less.

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

demand
standard Example Comparative example One 2 One 2 3 4 5 6 Prize
On The tensile strength
(kgf/㎟) 0.92↑ 1.15 1.08 1.23 0.88 1.32 0.95 1.09 1.09 Elongation (%) 100↑ 125.4 132.6 87.9 135.6 92.9 82.3 127.0 130.5 Heat resistant
(100℃/
168h) Tensile residual
(%) 75↑ 97.4 92.6 96.1 101.4 89.0 90.2 91.9 89.1 Kidney residual rate
(%) 50↑ 77.8 76.5 80.0 79.8 75.1 74.3 73.9 73.6 EN
50399 Combustion length (m) 2.0↓ 1.65 1.81 1.58 1.66 1.85 1.59 2.40 2.18 Maximum heat release rate
(kW) 60↓ 44.3 48.9 42.3 53.5 55.1 39.0 68.6 60.9 Total heat release rate
(MJ) 30↓ 19.8 22.1 17.6 20.8 16.8 13.5 37.8 29.9 Flame propagation speed
(W/s) 300↓ 221.1 234.9 250.4 249.2 188.1 154.2 289.0 237.4 Total smoke
(㎡) 50↓ 44.8 32.4 41.2 44.6 39.7 40.6 46.2 33.4 Best smoke
Speed(㎡/s) 0.25↓ 0.11 0.10 0.22 0.18 0.19 0.13 0.23 0.12 Drip(s) 10s↓ 10s↓ 10s↓ 10s↓ 10s↓ 10s↓ 10s↓ 10s↓ 10s↓ EN
50267
-2,3 pH 4.3↑ 5.3 5.3 5.5 5.2 5.1 5.3 4.9 5.2 conductivity
(μS/mm) 2.5↓ 2.2 2.1 2.0 2.3 2.3 2.0 2.1 2.1

As shown in Table 2, the non-halogen resin composition of Comparative Examples 1 and 3 did not contain a polyolefin elastomer resin or the elongation rate was significantly lowered because the content was below the standard, and the non-halogen resin composition of Comparative Example 2 was ethylene vinyl. It was confirmed that the content of the acetate resin was lower than the standard and the tensile strength was significantly lowered because the polyolefin elastomer resin was included in an excessive amount.

In addition, the non-halogen-based resin composition of Comparative Example 4 was magnesium hydroxide, and the content of natural magnesium hydroxide was excessive and the content of synthetic magnesium hydroxide was less than the standard, so it was excellent in flame retardancy, but it was confirmed that the elongation rate was significantly reduced.

In addition, the non-halogen resin composition of Comparative Example 5 significantly reduced the flame retardancy as the content of synthetic magnesium hydroxide was less than the standard. Has been confirmed.

On the other hand, the non-halogen resin composition of Examples 1 and 2 according to the present invention is a material for forming a sheath layer of a UTP cable, and both mechanical properties at room temperature and after heating, as well as high flame retardancy and low smoke resistance of C grade according to CPR certification Confirmed to be satisfied

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims described below. You will be able to do it. Therefore, if the modified implementation basically includes the elements of the claims of the present invention, it should be seen that all are included in the technical scope of the present invention.

Claims (9)

As a non-halogen resin composition for forming a sheath layer of a UTP cable,
An ethylene vinyl acetate (EVA) resin having a vinyl acetate content of 20 to 40% by weight, a polyolefin elastomer resin, and a base resin including a linear low-density polyethylene resin grafted with a polar group, and a non-halogen-based flame retardant,
The non-halogen-based flame retardant includes a flame retardant including aluminum hydroxide and magnesium hydroxide, and a flame retardant auxiliary including a silicic acid-based flame retardant, an antimony-based flame retardant, and a zinc-based flame retardant,
A UTP cable comprising a sheath layer formed from the non-halogen resin composition satisfies the C grade or higher of the CPR (Construction Products Regulation) certification, a non-halogen resin composition. The method of claim 1,
Based on 100 parts by weight of the base resin, the content of the ethylene vinyl acetate (EVA) resin is 40 to 65 parts by weight, the content of the polyolefin elastomer resin is 15 to 35 parts by weight, The content is characterized in that 15 to 35 parts by weight, non-halogen resin composition. The method according to claim 1 or 2,
Based on 100 parts by weight of the base resin, the content of aluminum hydroxide as the flame retardant is 45 to 65 parts by weight, the content of natural magnesium hydroxide in magnesium hydroxide as the flame retardant is 30 to 50 parts by weight, and the content of synthetic magnesium hydroxide is 115 to 135 Parts by weight, the content of the silicic acid-based flame retardant is 5 to 15 parts by weight, the content of the antimony-based flame retardant is 10 to 20 parts by weight, and the content of the zinc-based flame retardant is 5 to 15 parts by weight, non-halogen resin Composition. The method according to claim 1 or 2,
Non-halogen resin composition, characterized in that the polar group is maleic anhydride. The method according to claim 1 or 2,
The polyolefin elastomer resin is characterized in that it comprises an ethylene octene copolymer, non-halogen resin composition. The method according to claim 1 or 2,
The silicic acid-based flame retardant is characterized in that it contains a hydrous magnesium silicate, non-halogen resin composition. The method according to claim 1 or 2,
The antimony-based flame retardant is characterized in that it contains antimony trioxide, non-halogen resin composition. The method according to claim 1 or 2,
The zinc-based flame retardant is characterized in that it contains zinc borate, non-halogen resin composition. A UTP (UTP) cable comprising a sheath layer formed from the non-halogen resin composition of claim 1 or 2.