WO2020111911A1 - High-flame-retardant and low-smoke-emission nonhalogenated resin composition, and utp cable comprising sheath layer formed therefrom - Google Patents

Abstract

The present invention relates to a high-flame-retardant and low-smoke-emission nonhalogenated resin composition for forming the sheath layer of a UTP cable, and a UTP cable comprising a sheath layer formed therefrom. Specifically, the present invention relates to: a nonhalogenated resin composition satisfying a high flame retardancy and a low smoke emission of grade C or higher on the basis of the construction products regulation (CPR) which has recently been applied in Europe; and a UTP cable comprising a sheath layer formed therefrom.

Description

A UTP cable comprising a high flame retardant and low smoke non-halogen resin composition and a sheath layer formed therefrom

The present invention relates to a high flame retardant and low smoke non-halogen-based resin composition for forming a sheath layer of a UTP cable and a UTP cable comprising a sheath layer formed therefrom. Specifically, the present invention relates to a non-halogen-based resin composition that satisfies high flame retardancy and low flame retardancy of C grade or higher based on a CPR (Construction Products Regulation) standard currently applied in Europe, and a UTP cable comprising a sheath layer formed therefrom. will be.

UTP cable stands for unshielded twisted pair, also known as unshielded paired cable or unshielded twisted pair. The most common type of UTP cable is a copper wire, which is used as a general telephone line or a signal line connecting the environment of a local area network (LAN).

The outer surface of the UTP cable is covered with a sheath material, and the sheath layer of the sheath material is exposed to directly contact the outside. In the case of a plenum-class UTP cable, it is used to install in an environment without a duct, and thus, excessive smoke is generated when a fire occurs in a space where the cable or the like is installed.

Therefore, the plenum-class UTP cable should be made of a material having low flame retardancy and high flame retardant properties in that it can be used as a passage for fire diffusion in the case of a highly combustible material. However, in the case of insulating and sheath materials used in the conventional plenum class, the combustion gas toxicity index required by the new standard CPR class cannot be satisfied. Polyolefin resin is used as a material with relatively low combustion gas hazard. In particular, in the case of UTP cables with polyolefin sheath, CM and CMX flame retardants are generally satisfied, and various flame retardants based on metal hydroxides are applied to satisfy them. CM flame retardancy is evaluated according to the length of combustion after applying a flame for 20 minutes with a heat of 21 kW according to the UL 1685 standard.

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

On the other hand, it has been confirmed that the UTP cable applying a polyolefin sheath that satisfies the conventional CM flame retardant is D-class based on the CPR standard, and in order to satisfy the higher grade C or higher, the development of a new low-fueled high-flame retardant sheath material is urgently needed. .

An object of the present invention is to provide a UTP cable comprising a non-halogen-based resin composition satisfying high flame retardancy and low smoke retardancy of C grade or higher based on CPR (Construction Products Regulation) standards, and a sheath layer formed therefrom.

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

A non-halogen-based resin composition for forming a sheath layer of a UTP cable, a linear low density grafted with ethylene vinyl acetate (EVA) resin having a vinyl acetate content of 15 to 35% by weight, a polyolefin elastomer resin, and a polar group. A base resin comprising a polyethylene resin and a non-halogen-based flame retardant, the non-halogen-based flame retardant comprises a flame retardant comprising a metal hydroxide and a flame retardant aid comprising an antimony-based flame retardant and a zinc-based flame retardant, and the non-halogen-based resin It provides a non-halogen-based resin composition, the UTP cable comprising a sheath layer formed from the composition satisfies the C grade or higher of the Construction Products Regulation (CPR) certification.

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 40 parts by weight, the linear low density polyethylene with the polar group grafted The content of the resin is 15 to 30 parts by weight, it provides a non-halogen-based resin composition.

In addition, based on 100 parts by weight of the base resin, the content of the flame retardant is 180 to 230 parts by weight, the content of the antimony-based flame retardant is 20 to 40 parts by weight, and the content of the zinc-based flame retardant is 5 to 40 parts by weight To provide a non-halogen-based resin composition.

And, it may further include a calcium carbonate as a filler, the content of the filler, based on 100 parts by weight of the base resin, characterized in that 5 to 20 parts by weight, provides a non-halogen-based resin composition.

Furthermore, the polar group provides a non-halogen-based resin composition, characterized in that it is maleic anhydride.

On the other hand, the polyolefin elastomer resin provides a non-halogen-based resin composition, characterized in that it comprises an ethylene octene copolymer.

In addition, the metal hydroxide is characterized in that it comprises magnesium hydroxide, provides a non-halogen-based resin composition.

And, the antimony flame retardant provides a non-halogen-based resin composition, characterized in that it comprises an antimony trioxide.

Furthermore, the zinc-based flame retardant provides a non-halogen-based resin composition, characterized in that it comprises zinc borate.

On the other hand, a UTP cable including a sheath layer formed from the non-halogen-based resin composition is provided.

Here, the thickness of the sheath layer is characterized in that 0.5 to 0.8 mm, to provide a non-halogen-based resin composition.

In addition, the thickness of the sheath layer is characterized in that 0.6 to 0.7 mm, to provide a non-halogen-based resin composition.

The non-halogen-based resin composition according to the present invention secures the mechanical strength required in the sheath layer of the UTP cable, and at the same time, satisfies the high flame retardancy, low flame retardancy, and low toxicity of combustion gas based on CPR (Construction Products Regulation) standards. It shows effect.

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.

The present invention relates to a high flame retardant and low smoke nonhalogen based 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 ethylene vinyl acetate (EVA) resin, polyolefin elastomer resin, and a linear low density polyethylene resin grafted with polar groups, for example, maleic anhydride, glycidyl methacrylate, and the like. have.

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

Specifically, the ethylene vinyl acetate (EVA) resin has a vinyl acetate content of 15 to 35% 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 for the base resin, thereby improving the flame retardancy of the non-halogen-based resin composition compared to other compositions containing the same amount of flame retardant. In addition, by improving the dispersibility of the flame retardant in the base resin, it is possible to suppress the mechanical properties of the non-halogen-based resin composition, extrudability, etc. from being lowered due to aggregation of the flame retardant.

In addition, when the content of vinyl acetate in the vinyl acetate (EVA) resin is more than 35% by weight, the flame retardancy of the non-halogen-based resin composition is improved, while the mechanical strength is lowered, and conversely, when it is less than 15% 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 65 parts by weight, the content of the polyolefin elastomer resin is 15 to 40 parts by weight, and the polar group is grafted The content of the linear low density polyethylene resin may be 15 to 30 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 is lowered, whereas when it is more than 65 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 40 parts by weight, the mechanical strength of the non-halogen-based resin composition may be significantly reduced.

In addition, when the content of the linear low-density polyethylene resin with the polar group grafted is less than 15 parts by weight, the non-halogen-based resin composition has flame retardancy, mechanical strength and elongation, and extruding property due to reduced compatibility with additives such as the base resin and a flame retardant. Whereas, etc. may be greatly reduced, when the content is more than 30 parts by weight, the content of the ethylene vinyl acetate (EVA) resin or the polyolefin elastomer resin is relatively reduced, and thus the flame retardancy or elongation of the non-halogen-based resin composition is selectively significantly reduced. Can be.

The flame retardant includes a non-halogen-based flame retardant, specifically, a metal hydroxide such as magnesium hydroxide or aluminum hydroxide, preferably a flame retardant containing magnesium hydroxide and an antimony flame retardant, preferably an antimony trioxide and a zinc flame retardant, preferably It may include a flame retardant adjuvant containing zinc borate.

The flame retardant containing the magnesium hydroxide, etc., mainly improves the flame retardant, refractory, and smoke-retardant properties of the non-halogen-based resin composition in the event of a fire, and in particular, the magnesium hydroxide is endothermic, which is decomposed into metal oxides, that is, ceramics and water, at about 340°C or higher as shown below. In addition to lowering the ambient temperature by inducing a reaction, it is possible to perform a function of maintaining the flame retardant, fireproof, and smoke-retardant properties of the non-halogen-based resin composition even under severe conditions by the ceramic having improved strength and excellent water resistance. .

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

Here, the magnesium hydroxide or the like is a synthetic magnesium hydroxide or a natural magnesium hydroxide of a water-active type, and may or may not be treated with a hydrophobic surface treatment agent such as vinylsilane. Usually, 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 surface of the magnesium hydroxide is treated with hydrophobicity, the flame retardancy of the non-halogen-based resin composition is fine. It may degrade.

On the other hand, the surface of the magnesium hydroxide is not surface-treated with another material, and thus the compatibility between the magnesium hydroxide and the base resin is reduced by improving the filler loading of the flame retardant by the linear low density polyethylene resin with the polar group grafted. can do.

Melamine cyanurate, which has been generally used as a conventional flame retardant aid, has a problem of generating a corrosive combustion gas containing acid after combustion, replacing it with the antimony flame retardant and zinc flame retardant described above, but antimony The system flame retardant has a problem of high cost, and while controlling the content thereof, the reduction in flame retardancy according to this can be solved by the combination of the zinc flame retardant and the specific combination of the base resin described above.

Specifically, the antimony-based flame retardant including the antimony trioxide exhibits a flame retardant synergistic effect together with the metal hydroxide-based flame retardant in the event of a fire, so that the flame retardant and fire-resistant properties of the non-halogen-based resin composition such as lowering the ambient temperature can be maintained. Auxiliary flame retardant, refractory and smoke-retardant properties can be realized, and the zinc-based flame retardant containing zinc borate or the like forms a char when a fire occurs, a sheath layer formed from the non-halogen-based resin composition and a UTP comprising the same By maintaining the structure of the cable, it is possible to realize flame-retardant, fire-resistant and smoke-free properties.

The flame retardant may include 180 to 230 parts by weight of the metal hydroxide flame retardant based on 100 parts by weight of the polyolefin base resin, and the flame retardant aid is 20 to 40 parts by weight of the antimony flame retardant based on 100 parts by weight of the polyolefin base resin and The zinc flame retardant may include 5 to 40 parts by weight. In addition, the non-halogen-based resin composition may further include 5 to 20 parts by weight of calcium carbonate as a filler to lower its manufacturing cost.

The thickness of the sheath layer may be 0.5 to 0.8 mm in order to realize such high flame retardancy and low flame retardancy in the UTP cable including the sheath layer formed from the sheath composition. When the thickness of the sheath layer is less than 0.5 mm, the flame retardancy of the non-halogen-based resin composition is greatly reduced, whereas when it is more than 0.8 mm, flexibility of the non-halogen-based resin composition may be reduced.

The content of the flame retardant and the flame retardant auxiliary is precisely controlled as described above, thereby minimizing the production cost of the non-halogen-based resin composition, and at the same time, high flame retardancy and low flame retardancy of C grade or higher level of CPR (Construction Products Regulation) certification can be realized. There will be.

[Example]

1. Manufacturing example

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

	Example			Comparative example
	One	2	3	One	2	3	4	5	6
Suzy 1	55	50	60	60	45	55	55	55	55
Suzy 2	25	30	20	30	20	25	25	25	25
Suzy 3	20	20	20	10	35	20	20	20	20
Flame retardant 1	210	200	190	210	210	165	210	210	210
Flame retardant 2	25	30	35	25	25	25	25	25	25
Flame retardant 3	30	30	25	30	30	30	-	30	30
Flame retardant 4	-	-	-	-	-	-	30	-	-
Antioxidants and other additives	10	10	10	10	10	10	10	10	10
Total content	375	370	360	375	375	330	375	375	375
Sheath layer thickness (mm)	0.60	0.70	0.60	0.60	0.60	0.60	0.60	0.85	0.45

-Resin 1: Ethylene vinyl acetate (EVA) resin (vinyl acetate content: 28 wt%)-Resin 2: Polyolefin elastomer resin (ethylene octene copolymer)

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

-Flame retardant 1: magnesium hydroxide

-Flame retardant 2: antimony trioxide

-Flame retardant 3: zinc borate

-Flame retardant 4: melamine cyanurate

-Other additives: lubricant

2. Property evaluation

(1) Evaluation of tensile strength and elongation at room temperature

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

(2) Evaluation of tensile strength and elongation after heating

When the tensile strength and elongation of each of the cis layer specimens of Examples and Comparative Examples were left in an oven at 100° C. for 168 hours, and the tensile strength and elongation were measured (evaluation speed is 200 mm/min), the tensile and elongation ratios based on the room temperature tensile strength and elongation were measured. It should be 75% or more and 50% or more, respectively.

(3) Flexibility evaluation

When the UTP cable is pulled out from the inside of the packaging box where the UTP cable is rolled and stored in an '8' shape, there should be no kink phenomenon during visual inspection, and the data transmission characteristics should not be degraded due to the fine bending.

(4) Flame retardancy and smokeability evaluation

① Combustion length measurement

According to the standard EN 50399, the combustion length of the cable that was naturally extinguished and then propagated vertically after 20 minutes of flame was applied to each UTP cable specimen of Examples and Comparative Examples was measured, and the combustion length was required to satisfy the CPR B rating. It must be 1.5 m or less, and the combustion length must be 2.0 m or less to satisfy the CPR C rating.

② Peak Heat Release Rate (PHRR)

In accordance with the standard EN 50399, the flames are applied to each UTP cable specimen of Examples and Comparative Examples for 20 minutes to collect smoke generated during combustion, and measure the content of oxygen consumed, oxygen monoxide and carbon dioxide emitted, and smoke The temperature, flow rate, pressure difference, etc. were measured to comprehensively calculate the heat release rate, and the maximum value was selected. At this time, the maximum heat dissipation rate must be 30 kW or less to satisfy the CPR B rating, and the maximum heat dissipation rate must be 60 kW or less to satisfy the CPR C rating.

③ Total Heat Release (THR)

The heat release rate (HRR) values expressed as a function of time were calculated by integrating, and the total heat release rate to satisfy the CPR B class should be 15 MJ or less, and the total heat release rate to satisfy the CPR C class should be 30 MJ or less.

④ Fire Growth Rate (FIRA)

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

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

In accordance with the standard EN 50399, after applying a flame for 20 minutes for each UTP cable specimen in Examples and Comparative Examples, the total amount of smoke was measured after natural extinguishing, and the maximum rate of smoke was calculated from the amount of smoke generated over time. The burning time of the resulting spark was measured. The total smoke amount is 50 ㎡ or less, the maximum smoke rate is 0.25 ㎡/s or less, and the burning time of fire should be 10 seconds or less.

⑥ Hazardous combustion gas

According to the standard EN 50267-2,3, the sheath layer specimens of 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 to measure pH and conductivity. The pH should be 4.3 or higher and the conductivity should be 2.5 μS/mm or less.

Table 2 below shows the evaluation results of the properties.

		Requirements criteria	Example			Comparative example
			One	2	3	One	2	3	4	5	6
Room temperature	Tensile strength (kgf/㎟)	0.92↑	1.15	1.08	1.12	0.88	1.10	1.13	1.21	1.29	1.10
	Elongation (%)	100↑	125.4	132.6	128.7	115.8	75.6	129.6	122.4	121.0	127.3
Heat resistance (100℃/168h)	Tensile residual rate (%)	75↑	97.4	92.6	95.4	88.5	90.5	81.2	89.1	92.5	92.7
	Elongation residual rate (%)	50↑	77.8	76.5	72.1	65.7	81.2	78.2	72.5	71.7	75.7
EN50399	Combustion length (m)	2.0↓	1.65	1.61	1.88	1.84	1.75	Burnout	1.56	1.44	2.88
	Maximum heat release rate (kW)	60↓	44.3	48.9	50.1	52.4	47.5	89.7	37.5	42.4	55.8
	Total heat release rate (MJ)	30↓	19.8	22.1	18.6	19.6	20.1	60.7	18.9	19.0	28.6
	Flame propagation speed (W/s)	300↓	221.1	234.9	191.0	209.6	199.0	414.5	189.5	209.1	254.7
	Total smoke amount (㎡)	50↓	44.8	32.4	29.0	36.8	41.2	76.8	35.7	34.2	51.8
	Maximum smoke rate (㎡/s)	0.25↓	0.11	0.10	0.17	0.15	0.13	0.65	0.11	0.10	0.32
	Drip(s)	10s↓	10s↓	10s↓	10s↓	10s↓	10s↓	10s↑	10s↓	10s↓	10s↓
EN50267-2,3	pH	4.3↑	5.3	5.3	5.4	5.5	5.4	5.5	6.5	5.3	5.3
	Conductivity (μS/mm)	2.5↓	0.7	0.7	0.6	0.6	0.6	0.7	4.7	0.7	0.7
flexibility	Kink phenomenon when pulling	X	X	X	X	X	X	X	X	O	X

As shown in Table 2, in the non-halogen-based resin composition of Comparative Example 1, the content of the linear low-density polyethylene resin grafted with a polar group is significantly lower than the standard, and the mechanical strength is significantly reduced, and the non-halogen-based resin composition of Comparative Example 2 is a polar group It was confirmed that the content of the grafted linear low-density polyethylene resin exceeded the criterion and the elongation was significantly reduced.

In addition, in the non-halogen-based resin composition of Comparative Example 3, the content of the metal hydroxide flame retardant was substantially lower than the standard, and the overall flame retardancy and low flame retardancy were significantly reduced. The toxicity of the combustion gas was greatly increased, and the non-halogen-based resin composition of Comparative Example 5 had an excessive thickness of the sheath layer formed therefrom, thereby deteriorating the transmission characteristics of the UTP cable, whereas the non-halogen-based resin composition of Comparative Example 6 was It was confirmed that the thickness of the sheath layer formed therefrom was lower than the standard, and the flame retardancy was lowered.

On the other hand, the non-halogen-based resin composition of Examples 1 to 3 according to the present invention is a material for forming a sheath layer of a UTP cable, and both mechanical properties after heating at room temperature and heating and C-class high flame retardancy and low flame retardancy at the same time Satisfied.

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.

Claims (12)

1. As a non-halogen-based resin composition for forming a sheath layer of a UTP cable,

   Base resin and non-halogen-based flame retardant comprising ethylene vinyl acetate (EVA) resin having a vinyl acetate content of 15 to 35% by weight, a polyolefin elastomer resin, and a linear low density polyethylene resin grafted with polar groups,

   The non-halogen-based flame retardant includes a flame retardant comprising a metal hydroxide and a flame retardant aid including an antimony-based flame retardant and a zinc-based flame retardant,

   A non-halogen-based resin composition, wherein the UTP cable comprising a sheath layer formed from the non-halogen-based resin composition satisfies a C grade or higher of CPR (Construction Products Regulation) certification.
2. According to 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 40 parts by weight, and the polar group is grafted The content is 15 to 30 parts by weight, characterized in that, non-halogen-based resin composition.
3. The method according to claim 1 or 2,

   Based on 100 parts by weight of the base resin, the content of the flame retardant is 180 to 230 parts by weight, the content of the antimony-based flame retardant is 20 to 40 parts by weight, characterized in that the content of the zinc-based flame retardant is 5 to 40 parts by weight, Non-halogen-based resin composition.
4. The method according to claim 1 or 2,

   The filler may further include calcium carbonate,

   The content of the filler, based on 100 parts by weight of the base resin, characterized in that 5 to 20 parts by weight, non-halogen-based resin composition.
5. The method according to claim 1 or 2,

   The polar group is maleic anhydride, characterized in that the non-halogen-based resin composition.
6. The method according to claim 1 or 2,

   The polyolefin elastomer resin is characterized in that it comprises an ethylene octene copolymer, non-halogen-based resin composition.
7. The method according to claim 1 or 2,

   The metal hydroxide is characterized in that it comprises magnesium hydroxide, a non-halogen-based resin composition.
8. The method according to claim 1 or 2,

   The antimony-based flame retardant is characterized in that it comprises an antimony trioxide, non-halogen-based resin composition.
9. The method according to claim 1 or 2,

   The zinc flame retardant is characterized in that it comprises zinc borate, a non-halogen-based resin composition.
10. A UTP cable comprising a sheath layer formed from the non-halogen-based resin composition of claim 1.
11. The method of claim 10,

    The thickness of the sheath layer is characterized in that 0.5 to 0.8 mm, non-halogen-based resin composition.
12. The method of claim 11,

    The thickness of the sheath layer is characterized in that 0.6 to 0.7 mm, non-halogen-based resin composition.