WO2018151421A1 - Polymer composition for high-voltage cable, and cable comprising insulation layer and sheath layer which are formed therefrom - Google Patents

Abstract

The present invention relates to a polymer composition for a high-voltage cable, and a cable comprising an insulation layer and a sheath layer which are formed from the composition. Particularly, the present invention relates to a polymer composition which satisfies high insulation resistance characteristics required for a high-voltage cable and simultaneously satisfies a high level of flexibility in a trade-off relationship therewith, and which has excellent properties such as oil resistance, wear resistance, heat resistance, cold resistance and flame resistance. The present invention also relates to a cable comprising an insulation layer and a sheath layer which are formed from the polymer composition.

Description

A cable comprising a polymer composition for a high voltage cable and an insulating layer and a sheath layer formed therefrom

The present invention relates to a cable comprising a polymer composition for a high voltage cable and an insulating layer and a sheath layer formed therefrom. Specifically, the present invention satisfies the high insulation resistance characteristics required for high voltage cables and at the same time has a high degree of flexibility in conflict with the polymer composition and excellent properties such as oil resistance, wear resistance, heat resistance, cold resistance, flame resistance, etc. A cable comprising an formed insulating layer and a sheath layer.

High-voltage cable for electric vehicles corresponds to 150 ℃ class 600V, and there are products of various specifications depending on the cross-sectional area of the conductor.

Insulators and sheaths of high-voltage cables for electric vehicles are applied to ethylene vinyl acetate (EVA) resin having high vinyl acetate (VA) content or polyolefin elastomer (POE) having low melting point (Tm).

These insulators and sheaths meet the existing international standard ISO 6722-1, but are based on the existing international standard ISO 6722-1 from the European Union of Leading Automobile Manufacturers, the LV 216, especially cables with metal shielding layers. It is difficult to satisfy insulation resistance, oil resistance, etc. required by LV 216-2.

For example, the volume resistance of an insulator required by the ISO 6722-1 standard is 10 ⁹ Ω · mm, but the volume resistance of the insulator required by the LV 216 standard is 10 ¹³ Ω · mm, and the sheath usually protects the cable from the external environment. In order to secure mechanical properties such as strength and hardness, priority is given to securing the mechanical properties such as strength and hardness. In addition, the sheath also requires insulation performance according to the insulator.

Therefore, insulators and sheaths applied with ethylene vinyl acetate (EVA) resin having a high vinyl acetate (VA) content or polyolefin elastomer (POE) having a low melting point in order to secure the flexibility of the related art have a volume resistance of the insulator required by the LV 216 standard. In order to satisfy the volume resistance, if the material has a high melting point (Tm), the insulation resistance may be improved, but the flexibility of the insulator and the sheath may deteriorate, making it difficult to apply as an electric vehicle battery cable product.

In addition, automotive cables should satisfy the oil resistance characteristics for various oils, but when the resin of the polymer composition is changed to ensure insulation resistance and flexibility of the insulator, oil resistance, flame retardancy, etc. are greatly affected, and crosslinking according to the resin Mechanical properties such as abrasion resistance, heat resistance, etc. are greatly influenced by the method and the degree of crosslinking, and it is very difficult for all these properties to meet the LV 216 standard.

Therefore, a polymer composition and an insulating layer formed therefrom that satisfy the high insulation resistance characteristics required by the LV 216 standard and at the same time have a high degree of flexibility and have excellent properties such as oil resistance, abrasion resistance, heat resistance, cold resistance, and flame resistance. And a cable including a sheath layer is urgently needed.

It is an object of the present invention to provide a cable comprising a polymer composition which satisfies the high insulation resistance properties required by the LV 216 standard and at the same time has a high degree of flexibility, and an insulation layer and a sheath layer formed therefrom. .

In addition, an object of the present invention is to provide a cable comprising a polymer composition which satisfies the characteristics such as excellent oil resistance, abrasion resistance, heat resistance, cold resistance, flame resistance, and the like, and an insulating layer and a sheath layer formed therefrom.

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

A polymer composition for a high voltage cable, comprising a base resin and an additive, the base resin comprising a polypropylene resin, a polyolefin elastomer, ethylene propylene diene rubber, and ethylene vinyl acetate resin grafted with maleic anhydride, The insulating layer and the sheath layer formed from the polymer composition provide a polymer composition having a volume resistance of more than 10 ¹³ Ω · mm.

Here, the content of the polypropylene resin is 15 to 25 parts by weight, the content of the polyolefin elastomer is 30 to 50 parts by weight, the content of the ethylene propylene diene rubber is 20 to 40 parts by weight based on 100 parts by weight of the base resin. And the content of the ethylene vinyl acetate resin grafted with maleic anhydride is 8 to 13 parts by weight, to provide a polymer composition.

In addition, based on 100 parts by weight of the base resin, the content of the polypropylene resin is 17 to 24 parts by weight, the content of the polyolefin elastomer is 37 to 45 parts by weight, the content of the ethylene propylene diene rubber is 27 to 31 parts by weight And the content of the ethylene vinyl acetate resin grafted with maleic anhydride is 9 to 10 parts by weight, to provide a polymer composition.

On the other hand, based on 100 parts by weight of the base resin, the content of the polypropylene resin is 22 to 32 parts by weight, the content of the polyolefin elastomer is 25 to 35 parts by weight, the content of the ethylene propylene diene rubber is 27 to 35 parts by weight And the content of the ethylene vinyl acetate resin grafted with maleic anhydride is 8 to 13 parts by weight, to provide a polymer composition.

Here, based on 100 parts by weight of the base resin, the content of the polypropylene resin is 24 to 29 parts by weight, the content of the polyolefin elastomer is 29 to 33 parts by weight, the content of the ethylene propylene diene rubber is 29 to 33 parts by weight And the content of the ethylene vinyl acetate resin grafted with maleic anhydride is 10 to 11 parts by weight, to provide a polymer composition.

The polypropylene resin has a melting point (Tm) of 140 to 145 ° C and a specific gravity of 0.860 to 0.880, and the polyolefin elastomer has a melting point (Tm) of 90 to 100 ° C and a specific gravity of 0.890 to 0.910. To provide a composition.

Here, the ethylene propylene diene rubber has a specific gravity of 0.870 to 0.890 and a Mooney viscosity (ML1 + 4 (125 ℃)) is characterized in that 20 to 40, to provide a polymer composition.

Further, the additive provides a polymer composition, characterized in that it comprises at least one additive selected from the group consisting of flame retardants, crosslinking aids, antioxidants and lubricants.

Here, the flame retardant includes magnesium hydroxide or aluminum hydroxide, and based on 100 parts by weight of the base resin, the content of the flame retardant is 80 to 100 parts by weight, to provide a polymer composition.

In addition, the content of the flame retardant provides a polymer composition, characterized in that 87 to 95 parts by weight based on 100 parts by weight of the base resin.

The crosslinking aid includes a crosslinking multifunctional organic monomer of the base resin, and the content of the crosslinking aid is 2 to 5 parts by weight based on 100 parts by weight of the base resin. .

On the other hand, the additive provides a polymer composition, characterized in that it comprises one or more additives selected from the group consisting of flame retardants, flame retardant aids, crosslinking aids, antioxidants and lubricants.

Here, the flame retardant includes magnesium hydroxide or aluminum hydroxide, the flame retardant aid comprises a flame retardant, based on 100 parts by weight of the base resin, the content of the flame retardant is 95 to 110 parts by weight, the content of the flame retardant aid Silver is 0.6 to 1.2 parts by weight, to provide a polymer composition.

In addition, based on 100 parts by weight of the base resin, the content of the flame retardant is from 100 to 105 parts by weight, the content of the flame retardant aid is characterized in that the polymer composition, which provides 0.8 to 1.1 parts by weight.

The crosslinking aid includes a crosslinking multifunctional organic monomer of the base resin, and the content of the crosslinking aid is 2 to 5 parts by weight based on 100 parts by weight of the base resin. .

Meanwhile, conductors; An insulating layer surrounding the conductor and formed from the polymer composition of any one of claims 1 to 3; A metal shielding layer surrounding the insulating layer; And a sheath layer surrounding the metal shielding layer and formed from the polymer composition of any one of claims 1, 4 and 5.

The polymer composition for a high voltage cable of the present invention has a superior effect of satisfying the high insulation resistance required at the same time as the LV 216 standard by applying a base resin containing a specific resin at a specific compounding ratio, and at the same time having a high flexibility. Indicates.

In addition, the polymer composition for a high voltage cable of the present invention is applied to the base resin containing a specific resin in a specific compounding ratio, and excellent oil resistance, wear resistance, heat resistance, cold resistance required by the LV 216 standard through the application of a specific flame retardant, crosslinking method, crosslinking agent, etc. It shows an excellent effect of satisfying properties such as and flame retardancy.

1 schematically shows a cross-sectional structure of one embodiment of a high voltage cable comprising an insulating layer and a sheath layer formed from a polymer composition according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the invention is not limited to the embodiments described herein but 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 schematically shows a cross-sectional structure of one embodiment of a high voltage cable comprising an insulating layer and a sheath layer formed from a polymer composition according to the present invention.

As shown in FIG. 1, the high voltage cable according to the present invention includes a conductor 10, an insulation layer 20 formed around the conductor 10 and formed from the polymer composition of the present invention, and a metal shield surrounding the insulation layer 20. The layer 30 and the metal shielding layer 40 may include a sheath layer 40 formed from the polymer composition of the present invention.

The conductor 10 may apply a copper stranded wire combined with copper fine wires to secure flexibility of the cable, and the metal shielding layer 40 may be made of a metal material such as copper or aluminum to shield electromagnetic waves generated from the cable conductors. Can be done.

The polymer composition forming the insulating layer 20 and the sheath layer 40 may include a base resin, a flame retardant, a crosslinking aid, and the like dispersed in the resin, and may further include other additives such as an antioxidant and a lubricant. have.

Here, the base resin includes a blending resin of polypropylene (PP) resin, polyolefin elastomer (POE) resin, ethylene propylene diene rubber (EPDM) and ethylene vinyl acetate (EVA) resin grafted with maleic anhydride. can do.

* The polypropylene (PP) resin has a high melting point (Tm) of its own, excellent insulation resistance properties, oil resistance, and the like, and may include a propylene homopolymer and / or a propylene copolymer, and the propylene homopolymer may have a total monomer weight. Polypropylene formed by polymerization of at least 99% by weight, preferably at least 99.5% by weight, of propylene.

The propylene copolymer is propylene and ethylene or α-olefin having 4 to 12 carbon atoms, for example, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, Comonomers selected from 1-dodecene and combinations thereof, preferably copolymers with ethylene. This is because copolymerization of propylene and ethylene shows hard and flexible properties.

The propylene copolymer may include a random propylene copolymer and / or a block propylene copolymer, and the random propylene copolymer refers to a propylene copolymer in which an propylene monomer and another olefin monomer are arbitrarily alternately arranged.

The polypropylene (PP) resin may have a melting point (Tm) of 140 to 145 ° C and a specific gravity of 0.860 to 0.880. If the melting point of the polypropylene (PP) resin is less than 140 ℃ or specific gravity is less than 0.860, the insulation resistance properties of the insulation and sheath composition, mechanical properties such as wear resistance, heat resistance, etc. may be insufficient, while melting point is more than 145 ℃ or specific gravity If it is greater than 0.880, the flexibility of the insulation and sheath composition may be greatly reduced.

In the case of the polymer composition for forming the insulating layer 20, the content of the polypropylene (PP) resin may be 15 to 25 parts by weight, preferably 17 to 24 parts by weight based on 100 parts by weight of the base resin. In the case of the polymer composition forming the sheath layer 40, the content of the polypropylene (PP) resin may be 22 to 32 parts by weight, preferably 24 to 29 parts by weight based on 100 parts by weight of the base resin.

When the content of the polypropylene (PP) resin is less than the reference content, the insulation resistance characteristics of the insulating layer 20 and the sheath layer 40, mechanical properties such as wear resistance, heat resistance, etc. may be insufficient. If it exceeds the reference content, the flexibility of the insulating layer 20 and the sheath layer 40 may be greatly reduced.

The polyolefin elastomer (POE) may further improve insulation resistance, oil resistance, and the like of the polymer composition, and may have a melting point (Tm) of 90 to 100 ° C. and specific gravity of 0.890 to 0.910. If the melting point of the polyolefin elastomer (POE) is less than 90 ℃ or specific gravity is less than 0.890, the mechanical properties such as insulation resistance characteristics, wear resistance, heat resistance, oil resistance, etc. of the polymer composition may be insufficient, while the melting point is more than 100 ℃ or specific gravity If it is more than 0.910, the flexibility, cold resistance, etc. of the polymer composition may be greatly reduced.

In the case of the polymer composition forming the insulating layer 20, the content of the polyolefin elastomer (POE) may be 30 to 50 parts by weight, preferably 37 to 45 parts by weight based on 100 parts by weight of the base resin, the sheath In the case of the polymer composition forming the layer 40, the content of the polyolefin elastomer (POE) may be 25 to 35 parts by weight, preferably 29 to 33 parts by weight based on 100 parts by weight of the base resin.

When the content of the polyolefin elastomer (POE) is less than the reference content, the insulation resistance characteristics, oil resistance, etc. of the polymer composition may be insufficient, whereas when the polyolefin elastomer (POE) is exceeded, the flexibility, cold resistance, etc. of the polymer composition may be greatly reduced. .

The ethylene propylene diene rubber (EPDM) may further improve the flexibility, cold resistance, etc. of the polymer composition, specific gravity may be 0.870 to 0.890, Mooney viscosity (ML1 + 4 (125 ° C)) may be 20 to 40. When the specific gravity of the ethylene propylene diene rubber (EPDM) is less than 0.870 or the Mooney viscosity (ML1 + 4 (125 ° C.)) is less than 20, the mechanical properties such as insulation resistance, wear resistance, and heat resistance of the polymer composition may be insufficient. When the specific gravity is greater than 0.890 or the Mooney viscosity (ML1 + 4 (125 ° C.)) is greater than 40, flexibility, flexibility, and cold resistance of the polymer composition may be insufficient.

In the case of the polymer composition forming the insulating layer 20, the content of the ethylene propylene diene rubber (EPDM) may be 20 to 40 parts by weight, preferably 27 to 31 parts by weight based on 100 parts by weight of the base resin. In the case of the polymer composition forming the sheath layer 40, the content of the ethylene propylene diene rubber (EPDM) may be 27 to 35 parts by weight, preferably 29 to 33 parts by weight based on 100 parts by weight of the base resin. .

When the content of the ethylene propylene diene rubber (EPDM) is lower than the reference content, the flexibility, cold resistance, etc. of the polymer composition may be lowered, whereas when the content of the ethylene propylene diene rubber (EPDM) is lower than the reference content, the mechanical properties such as insulation resistance and wear resistance of the polymer composition, Heat resistance and the like can be greatly reduced.

The maleic anhydride-grafted ethylene vinyl acetate (EVA) resin may increase the compatibility of the base resin and the inorganic flame retardant to improve the flame retardancy and mechanical properties of the polymer composition.

In the case of the polymer composition forming the insulating layer 20, the content of the maleic anhydride-grafted ethylene vinyl acetate (EVA) resin is 8 to 13 parts by weight, preferably 9 based on 100 parts by weight of the base resin. In the case of the polymer composition forming the sheath layer 40, the content of the maleic anhydride-grafted ethylene vinyl acetate (EVA) resin may be from about 10 parts by weight to 10 parts by weight, based on 100 parts by weight of the base resin. It may be 10 parts by weight, preferably 10 to 11 parts by weight.

When the content of the ethylene vinyl acetate (EVA) resin grafted with maleic anhydride is lower than the reference content, the flame resistance, flexibility, and cold resistance of the polymer composition may be lowered, whereas the insulation resistance of the polymer composition that is higher than the reference content is decreased. Properties, mechanical properties such as abrasion resistance, heat resistance, and the like can be greatly reduced.

The flame retardant dispersed in the base resin may improve the flame retardancy of the insulating composition, and may include, for example, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, and to improve dispersibility in the base resin. It may be surface-treated with a hydrophobic material such as silane, and the polymer composition forming the sheath layer 40 may further include a flame retardant as a flame retardant aid, the flame retardant in the resin compatible with the base resin Flame retardants can be added in the form of highly dispersed masterbatches.

In the case of the polymer composition forming the insulating layer 20, the content of the flame retardant may be 80 to 100 parts by weight, preferably 87 to 95 parts by weight based on 100 parts by weight of the base resin, and the sheath layer 40 In the case of forming the polymer composition, the content of the flame retardant may be 95 to 110 parts by weight, preferably 100 to 105 parts by weight based on 100 parts by weight of the base resin, and the content of the flame retardant aid is based on 100 parts by weight of the base resin. 0.6 to 1.2, preferably 0.8 to 1.1 parts by weight.

When the content of the flame retardant and the flame retardant auxiliary agent is less than the reference content, the flame retardancy of the polymer composition may be insufficient, whereas when the content of the flame retardant and the flame retardant aid is exceeded, mechanical properties such as insulation resistance and wear resistance of the polymer composition may be greatly reduced. have.

The crosslinking aid may be added for irradiation crosslinking of the base resin, and may include, for example, a polyfunctional organic monomer. In the case of the polymer composition forming the insulating layer 20, the content of the crosslinking aid may be It may be 2 to 5 parts by weight, preferably 3 to 5 parts by weight based on 100 parts by weight of the base resin, and in the case of the polymer composition forming the sheath layer 40, the amount of the crosslinking aid is based on 100 parts by weight of the base resin. 2 to 5, preferably 3 to 4 parts by weight.

Here, when the content of the crosslinking aid is less than the reference content, the crosslinking degree of the base resin may significantly lower the insulation resistance characteristics, mechanical properties such as wear resistance, heat resistance, etc., of the base resin, but exceeds the reference content. In the case of flexibility, cold resistance, etc. of the polymer composition may be lowered.

As the other additive, an antioxidant may be further added to ensure long-term heat resistance of the polymer composition, and the lubricant may be further added to improve compatibility of the base resin with other additives.

EXAMPLE

1. Manufacturing Example

By preparing the polymer composition by mixing for 30 minutes at 150 ℃ using a 3L kneader equipment with the composition shown in Table 1 below by using the 45 mm extruder to form the insulating layer and the sheath layer shown in Table 2 below Cable specimens were prepared. When the cable specimens were manufactured, the conductor was applied with an interlocking line 6SQ, and after cross-extrusion irradiation crosslinking was performed when the insulating layer and the sheath layer were formed from the polymer composition, a metal shielding layer was disposed between the insulating layer and the sheath layer. The unit of the content shown in Table 1 below is parts by weight, and a part of the additives commonly added is omitted.

	Prescription 1	Prescription 2	Prescription 3	Prescription 4	Prescription 5	Prescription 6	Prescription 7	Prescription 8	Prescription 9	Prescription 10
Resin 1	23	18	19	23	40	28	27	25	26	20
Resin 2	38	44	26	38	20	30	32	32	30	25
Resin 3	30	28	35		35	31	31	32	33	45
Resin 4	9	10	20	9	5	11	10	11	11	10
Resin 5				30
Flame retardant 1	90	90	90	90	90	105	100	100	120	110
Flame Retardant 2						0.8	1.0	1.1		0.9
Crosslinking aid	3	3	3	3	3	3	3	3	3	3

Resin 1: Polypropylene (melting point: 141 ° C; specific gravity: 0.870)

Resin 2: polyolefin elastomer (melting point: 97 ° C; specific gravity: 0.902)

Resin 3: Ethylene propylene diene rubber (specific gravity: 0.880; Mooney viscosity (ML1 + 4 (125 ° C)): 21 ~ 29)

Resin 4: Ethylene vinyl acetate grafted with maleic anhydride

Resin 5: Ethylene vinyl acetate (melting point: 62 ° C; vinyl acetate content: 33 wt%)

-Flame retardant 1: Magnesium hydroxide coated with vinyl silane (BET specific surface area: 4.0 ~ 6.0 ㎡ / g)

-Flame retardant 2: fire retardant supplement

-Crosslinking aid: trimethylolpropane trimethacrylate (TMPTMA)

	Example 1	Example 2	Example 3	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4	Comparative Example 5	Comparative Example 6
Insulation layer	Prescription 1	Prescription 1	Prescription 2	Prescription 1	Prescription 6	Prescription 2	Prescription 3	Prescription 2	Prescription 1
Sheath layer	Prescription 6	Prescription 7	Prescription 8	Prescription 1	Prescription 5	Prescription 4	Prescription 6	Prescription 9	Prescription 10

2. Property evaluation

1) Oil resistance evaluation

In accordance with the LV 216 standard, the cable specimens of each of Examples and Comparative Examples were soaked in a beaker containing gasoline for 20 hours at room temperature, and then taken out, and the cable outer diameter was measured after 30 minutes. If the outer diameter after immersion exceeds 15% of the increased diameter compared to the outer diameter before immersion, it is less than the standard.

2) Insulation resistance evaluation

Insulation resistance was measured for each of the cable specimens of Examples and Comparative Examples according to the LV 216 standard. Insulation resistance measurement method was applied according to ISO 6722-1, but with 70% 1% saline instead of 70 ℃ water, and the insulation resistance between the sheath layer and the metal shielding layer was measured when evaluating the insulation resistance. The measured insulation resistance should exceed 10 ¹³ Ω · mm.

3) Flexibility Assessment

Tensile strength at the time of 2% elongation was measured for each of the insulated specimens of the Examples and Comparative Examples using a UTM facility. The level of flexibility is determined by comparing the tensile strength value at the time of 2% elongation of the prescription meeting the existing ISO standard.

4) Heat resistance evaluation

Long-term / short-term heat resistance was evaluated for each of the cable specimens of the Examples and Comparative Examples according to the LV 216 standard, and the long-term heat resistance was maintained for 1 hour after applying the voltage of 1 kV in water for 1 minute after the specimen was kept at 150 ° C. for 3,000 hours. Insulation breakage should not occur, short term heat resistance must be maintained at 175 ℃ for 240 hours, then pass low temperature bending test in -25 ℃ chamber, very good (◎), good (○), bad (△), very bad It evaluates as (x).

5) Cold resistance evaluation

According to the LV 216 standard, each cable specimen according to the example and the comparative example was suspended according to the conductor size according to the conductor size, stayed for 4 hours in the oven at -40 ℃, and wound around the rod of the specified standard to see if cracks occurred. Check it. If no cracking occurs, no breakdown shall occur during the application of a voltage of 1 kV in water for one minute.

6) Wear resistance evaluation

In accordance with the ISO 6722-1 standard, a 0.45 mm diameter needle was reciprocated perpendicularly to the specimen with 7 N load applied to each of the cable specimens of Examples and Comparative Examples. If the sheath layer wears and the needle contacts the shielding layer, the evaluation is complete and the round trip frequency should be 1,500 or more.

7) Flame retardancy evaluation

According to the LV 216 standard, fix each cable specimen and burner at 45 ° angle from the ground, and arrange the specimen and burner to be perpendicular to each other. It must be digested within.

The physical property evaluation results are shown in Table 3 below.

	spec.	Example			Comparative example
		One	2	3	One	2	3	4	5	6
Oil resistance	<15%	9.7	10.5	10.2	10.2	10.7	17.8	11.4	10.6	13.8
Insulation Resistance	Ωmm	3.70E + 14	2.10E + 14	2.37E + 14	7.68E + 13	1.17E + 14	2.37E + 12	9.72E + 13	9.72E + 13	9.72E + 13
flexibility	-	0.295	0.284	0.291	0.289	0.380	0.303	0.415	0.310	0.317
Heat resistance		◎	◎	◎	◎	×	◎	◎	◎	◎
Cold resistance	No crack	No crack	No crack	No crack	No crack	No crack	No crack	No crack	Crack	No crack
Wear resistance	> 1,500 times	◎	◎	◎	◎	◎	952	◎	◎	1,374
Flame retardant	Digest in 70 seconds	◎	◎	◎	×	◎	×	◎	×	◎

As shown in Table 3, the cable specimen of Comparative Example 1 did not satisfy the flame retardancy because the sheath layer was formed from the polymer composition of Formulation 1 containing no flame retardant aid, the cable specimen of Comparative Example 2 is an insulating layer and sheath The layers were formed from the polymer compositions of Formulations 6 and 5, each containing an excessive amount of polypropylene resin, resulting in poor heat resistance due to unstable properties after crosslinking due to the properties of the polypropylene, and deteriorated flexibility, and the cable specimen of Comparative Example 3 was a sheath layer. It was formed from the polymer composition of Formula 4 containing ethylene vinyl acetate resin instead of the ethylene propylene diene rubber, and did not satisfy flame retardancy, oil resistance, abrasion resistance, and the like. Polymer composition of formula 3 containing an excess of ethylene vinyl acetate resin Formed in the polymer composition of Comparative Example 5, the sheath layer was formed from the polymer composition of Formulation 9 in which the flame retardant 1 was excessively added and the flame retardant 2 was not added, thereby reducing the flame resistance and the cold resistance. The cable specimens were formed from the polymer composition of Formula 10 in which the sheath layer contained an excessive amount of ethylene propylene diene rubber so that the abrasion resistance did not meet the specification.

On the other hand, the cable specimens of Examples 1 to 3 of the present invention satisfy all of the high insulation resistance properties and the flexibility in conflict with the standard required by the LV 216 standard. It was also confirmed that the physical properties were excellent.

Although the present specification has been described with reference to preferred embodiments of the invention, those skilled in the art may variously modify and change the invention without departing from the spirit and scope of the invention as set forth in the claims set forth below. Could be done. 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.

Claims (16)

1. A polymer composition for high voltage cable,

   Base resins and additives,

   The base resin comprises polypropylene resin, polyolefin elastomer, ethylene propylene diene rubber and ethylene vinyl acetate resin grafted with maleic anhydride,

   The insulating layer and the sheath layer formed from the polymer composition have a volume resistance of more than 10 ¹³ Ω · mm.
2. The method of claim 1,

   Based on 100 parts by weight of the base resin, the content of the polypropylene resin is 15 to 25 parts by weight, the content of the polyolefin elastomer is 30 to 50 parts by weight, the content of the ethylene propylene diene rubber is 20 to 40 parts by weight and the The content of the ethylene vinyl acetate resin grafted maleic anhydride (grafted), characterized in that 8 to 13 parts by weight, the polymer composition.
3. The method of claim 2,

   Based on 100 parts by weight of the base resin, the content of the polypropylene resin is 17 to 24 parts by weight, the content of the polyolefin elastomer is 37 to 45 parts by weight, the content of the ethylene propylene diene rubber is 27 to 31 parts by weight and the The content of ethylene vinyl acetate resin grafted maleic anhydride is characterized in that 9 to 10 parts by weight, the polymer composition.
4. The method of claim 1,

   Based on 100 parts by weight of the base resin, the content of the polypropylene resin is 22 to 32 parts by weight, the content of the polyolefin elastomer is 25 to 35 parts by weight, the content of the ethylene propylene diene rubber is 27 to 35 parts by weight and the The content of the ethylene vinyl acetate resin grafted maleic anhydride (grafted), characterized in that 8 to 13 parts by weight, the polymer composition.
5. The method of claim 4, wherein

   Based on 100 parts by weight of the base resin, the content of the polypropylene resin is 24 to 29 parts by weight, the content of the polyolefin elastomer is 29 to 33 parts by weight, the content of the ethylene propylene diene rubber is 29 to 33 parts by weight and the The content of the ethylene vinyl acetate resin grafted maleic anhydride (grafted), characterized in that 10 to 11 parts by weight, the polymer composition.
6. The method according to any one of claims 1 to 5,

   The polypropylene resin has a melting point (Tm) of 140 to 145 ° C. and specific gravity of 0.860 to 0.880, and the polyolefin elastomer has a melting point (Tm) of 90 to 100 ° C. and specific gravity of 0.890 to 0.910.
7. The method of claim 6,

   The ethylene propylene diene rubber has a specific gravity of 0.870 to 0.890 and a Mooney viscosity (ML1 + 4 (125 ℃)) is characterized in that the 20 to 40, the polymer composition.
8. The method according to any one of claims 1 to 3,

   The additive is characterized in that it comprises at least one additive selected from the group consisting of flame retardants, crosslinking aids, antioxidants and lubricants.
9. The method of claim 8,

   The flame retardant comprises magnesium hydroxide or aluminum hydroxide, based on 100 parts by weight of the base resin, characterized in that the content of the flame retardant is 80 to 100 parts by weight, polymer composition.
10. The method of claim 9,

    The content of the flame retardant is a polymer composition, characterized in that 87 to 95 parts by weight based on 100 parts by weight of the base resin.
11. The method of claim 8,

    The crosslinking aid comprises a multifunctional organic monomer for irradiation crosslinking of the base resin, the content of the crosslinking aid is characterized in that 2 to 5 parts by weight based on 100 parts by weight of the base resin, polymer composition.
12. The method according to any one of claims 1, 4 and 5,

    The additive is characterized in that it comprises at least one additive selected from the group consisting of flame retardants, flame retardant aids, crosslinking aids, antioxidants and lubricants.
13. The method of claim 12,

    The flame retardant includes magnesium hydroxide or aluminum hydroxide, the flame retardant aid comprises a flame retardant, based on 100 parts by weight of the base resin, the content of the flame retardant is 95 to 110 parts by weight, the content of the flame retardant aid is 0.6 To 1.2 parts by weight, the polymer composition.
14. The method of claim 13,

    Based on 100 parts by weight of the base resin, the content of the flame retardant is 100 to 105 parts by weight, the content of the flame retardant aid is characterized in that the polymer composition, 0.8 to 1.1 parts by weight.
15. The method of claim 12,

    The crosslinking aid comprises a multifunctional organic monomer for irradiation crosslinking of the base resin, the content of the crosslinking aid is characterized in that 2 to 5 parts by weight based on 100 parts by weight of the base resin, polymer composition.
16. Conductor;

    An insulating layer surrounding the conductor and formed from the polymer composition of any one of claims 1 to 3;

    A metal shielding layer surrounding the insulating layer; And

    Cable comprising a sheath layer surrounding the metal shielding layer and formed from the polymer composition of any one of claims 1, 4 and 5.

Images