WO2018151420A1 - Insulation composition for high-voltage cable, and cable comprising insulation layer formed therefrom - Google Patents

Abstract

The present invention relates to an insulation composition for a high-voltage cable, and a cable comprising an insulation layer formed from the composition. Particularly, the present invention relates to an insulation 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 and flame resistance. The present invention also relates to a cable comprising an insulation layer formed from the insulation composition.

Description

Cable comprising insulating composition for high voltage cable and insulating layer formed therefrom

The present invention relates to a cable comprising an insulating composition for a high voltage cable and an insulating 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 insulation composition having excellent properties such as oil resistance, abrasion resistance, heat resistance, flame resistance, and the like formed from A cable comprising a layer is provided.

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.

In order to ensure flexibility of the conventional high voltage cable for electric vehicles, ethylene vinyl acetate (EVA) resin having high vinyl acetate (VA) content or polyolefin elastomer (POE) having a low melting point (Tm) has been applied.

These insulators meet the existing international standard ISO 6722-1, but are based on the newly developed international standard LV 216 based on the existing international standard ISO 6722-1 from the European Association of Leading Automobile Manufacturers, especially cables with no metal shielding layer. It is difficult to satisfy the insulation resistance characteristics, oil resistance, etc. required by the Korean Standard LV 216-1.

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 other methods of evaluation and determination of various characteristics. The criteria have changed.

Therefore, insulators using ethylene vinyl acetate (EVA) resin having a high vinyl acetate (VA) content or polyolefin elastomer (POE) having a low melting point can satisfy the volume resistance of the insulator required by the LV 216 standard in order to secure conventional flexibility. If the material has a high melting point (Tm) to satisfy the volume resistance, the insulation resistance may be improved, but the flexibility deteriorates, making it difficult to apply as an electric vehicle battery cable product.

In addition, the automotive cable should satisfy the oil resistance characteristics for various oils, but when the resin of the insulation composition is changed to ensure insulation resistance and flexibility of the insulator, oil resistance, flame retardancy, etc. are greatly affected, and crosslinking according to 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, it satisfies the high insulation resistance characteristics required by the LV 216 standard and at the same time has a high degree of flexibility in conflict with the insulation composition having excellent properties such as oil resistance, abrasion resistance, heat resistance and flame resistance, and an insulating layer formed therefrom. It is a situation that a cable is desperately required.

It is an object of the present invention to provide a cable comprising an insulating composition and an insulating layer formed therefrom that satisfy the high insulation resistance properties required by the LV 216 standard and at the same time have a high degree of flexibility.

In addition, an object of the present invention is to provide a cable comprising an insulating composition and an insulating layer formed therefrom satisfying the characteristics such as excellent oil resistance, wear resistance, heat resistance, flame retardancy required by the LV 216 standard.

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

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

Here, based on 100 parts by weight of the base resin, the content of the polypropylene resin is 12 to 28 parts by weight, the content of the polyolefin elastomer is 25 to 50 parts by weight, the content of the ethylene propylene diene rubber is 20 to 50 parts by weight. And the content of the ethylene vinyl acetate resin grafted with maleic anhydride is 5 to 18 parts by weight.

In addition, based on 100 parts by weight of the base resin, the content of the polypropylene resin is 16 to 24 parts by weight, the content of the polyolefin elastomer is 30 to 45 parts by weight, the content of the ethylene propylene diene rubber is 30 to 40 parts by weight. And the content of the ethylene vinyl acetate resin grafted with maleic anhydride is 8 to 15 parts by weight.

Meanwhile, 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, insulation To provide a composition.

Herein, the ethylene propylene diene rubber has a specific gravity of 0.870 to 0.890 and a Mooney viscosity (ML1 + 4 (125 ° C.)) of 20 to 40, providing an insulation composition.

On the other hand, the additive provides an insulation composition, characterized in that it comprises one or more additives 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 105 parts by weight, to provide an insulation composition.

In addition, the content of the flame retardant provides an insulation composition, characterized in that 85 to 95 parts by weight based on 100 parts by weight of the base resin.

And, the crosslinking aid comprises a cross-linking multifunctional organic monomer of the base resin, the content of the crosslinking aid provides an insulating composition, characterized in that 2 to 5 parts by weight based on 100 parts by weight of the base resin. .

Meanwhile, conductors; And an insulation layer surrounding the conductor and formed from the insulation composition.

The insulation composition for a high voltage cable according to the present invention has a superior effect of satisfying the high insulation resistance required by the LV 216 standard and satisfying a high degree of flexibility by applying a base resin containing a specific resin at a specific compounding ratio. Indicates.

In addition, the insulation 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 through the application of a specific flame retardant, crosslinking method, crosslinking agent, etc. excellent oil resistance, wear resistance, heat resistance, flame resistance It shows an excellent effect of satisfying such characteristics.

1 schematically illustrates a cross-sectional structure of one embodiment of a high voltage cable comprising an insulating layer formed from an insulating 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.

The present invention relates to an insulation composition for high voltage cables.

The insulating composition according to the present invention includes a base resin and a flame retardant, a crosslinking aid, and the like dispersed in the resin, and may further include other additives such as antioxidants and lubricants.

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), which is excellent in insulation resistance, 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. By polypropylene is meant 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 characteristics of the insulating composition, mechanical properties such as wear resistance, heat resistance, etc. may be insufficient, while melting point is more than 145 ℃ or 0.880 specific gravity If exceeded, the flexibility of the insulating composition may be greatly reduced.

The content of the polypropylene (PP) resin may be 12 to 28 parts by weight, preferably 16 to 24 parts by weight based on 100 parts by weight of the base resin, when the content of the polypropylene (PP) resin is less than 12 parts by weight Insulation resistance properties of the insulating composition, mechanical properties such as wear resistance, heat resistance and the like may be insufficient, while if greater than 28 parts by weight, the flexibility of the insulating composition of the insulating composition may be greatly reduced.

The polyolefin elastomer (POE) may further improve insulation resistance, oil resistance, and the like of the insulation 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 insulation resistance characteristics of the insulating composition, mechanical properties such as wear resistance, heat resistance, oil resistance, etc. 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, and the like of the insulating composition may be greatly reduced.

The content of the polyolefin elastomer (POE) may be 25 to 50 parts by weight, preferably 30 to 45 parts by weight based on 100 parts by weight of the base resin, and the insulation composition when the content of the polyolefin elastomer (POE) is less than 25 parts by weight Insulation resistance properties, oil resistance, etc. may be insufficient, whereas when more than 50 parts by weight, flexibility, cold resistance, etc. of the insulation composition may be greatly reduced.

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

The content of the ethylene propylene diene rubber (EPDM) may be 20 to 50 parts by weight, preferably 30 to 40 parts by weight based on 100 parts by weight of the base resin, and the content of the ethylene propylene diene rubber (EPDM) is 20 parts by weight. If less than, flexibility, cold resistance, etc. of the insulating composition may be lowered, whereas if it is more than 50 parts by weight, the mechanical properties such as insulation resistance characteristics, wear resistance, heat resistance and the like of the insulating composition may be significantly reduced.

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

The amount of the maleic anhydride-grafted ethylene vinyl acetate (EVA) resin may be 5 to 18 parts by weight based on 100 parts by weight of the base resin, and the maleic anhydride-grafted ethylene vinyl acetate (EVA) resin If the content is less than 5 parts by weight, the flame retardancy, flexibility, cold resistance, etc. of the insulating composition may be lowered, whereas if it is more than 18 parts by weight, the mechanical properties such as insulation resistance characteristics, wear resistance, heat resistance, etc. of the insulating composition may be significantly 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.

The content of the flame retardant may be 80 to 105 parts by weight, preferably 85 to 95 parts by weight based on 100 parts by weight of the base resin. If the content of the flame retardant is less than 80 parts by weight, the flame retardancy of the insulating composition may be insufficient, whereas if it is more than 105 parts by weight, the mechanical properties such as insulation resistance characteristics, wear resistance and the like of the insulating composition may be greatly reduced.

The crosslinking aid may be added for irradiation crosslinking of the base resin, and may include, for example, a polyfunctional organic monomer, and its content may be 2 to 5 parts by weight based on 100 parts by weight of the base resin.

Here, when the content of the crosslinking aid is less than 2 parts by weight, the degree of crosslinking of the base resin may be significantly lower than the insulation resistance properties, mechanical properties such as wear resistance, heat resistance, etc. In this case, flexibility, cold resistance, etc. of the insulating composition may be lowered.

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

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

As shown in FIG. 1, the cable according to the invention may comprise a conductor 10 and an insulation layer 20 formed around the conductor 10 and formed from the insulation composition described above. The conductor 10 is preferably a copper stranded wire formed by combining fine wires of copper material in order to secure flexibility of the cable, and the conductor 10 has a nominal cross-sectional area and a thickness of the insulating layer 20. Can be appropriately selected by those skilled in the cable art.

EXAMPLE

1. Manufacturing Example

The cable specimen was prepared by preparing an insulating composition by mixing at 150 ° C. for 30 minutes using a 3L kneader facility with the composition shown in Table 1 below, and then forming an insulating layer using a 45 mm extruder. Conductor wire 6SQ was applied to the conductors in the preparation of the cable specimens, and irradiation crosslinking was performed after extrusion when forming an insulation layer from the insulation composition. The unit of the content shown in Table 1 below is parts by weight, and a part of the additives commonly added is omitted.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Resin 1 17 19 23 17 30 19 19 17 23 Resin 2 42 34 33 58 26 26 34 42 33 Resin 3 31 35 35 15 35 35 35 31 Resin 4 10 12 9 10 9 20 12 10 9 Resin 5 35 Additives1 90 90 90 90 90 90 120 90 90 Additive2 3 3 3 3 3 3 3 3 Dose 5 3 5 5 5 5 5 5

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%)

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

Additive 2: Trimethylolpropane trimethacrylate (TMPTMA)

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 is to comply with ISO 6722-1, but with 70% 1% saline instead of 70 ℃ water, the measured insulation resistance should exceed 10 ¹³ Ω · ㎜.

3) Flexibility Assessment

Tensile strength at 2% elongation was measured for each of the cable 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.

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

spec. Example Comparative example One 2 3 One 2 3 4 5 6 Oil resistance <15% 8.6 7.5 8.3 6.8 8.8 9.2 - - 13.8 Insulation Resistance Ωmm 8.41E + 13 7.24E + 13 9.72E + 13 7.68E + 13 1.17E + 14 - - - 1.22E + 12 flexibility 0.283 0.280 0.291 0.452 0.473 0.434 - - 0.322 Heat resistance ◎ ◎ ◎ ◎ △ ◎ - × ◎ Cold resistance No crack No crack No crack No crack No crack No crack No crack Crack - No crack

As shown in Table 2, the cable specimen of Comparative Example 1 was improved in oil resistance due to excessive polyolefin elastomer content in the insulating layer, but deteriorated in flexibility by insufficient content of ethylene propylene diene rubber, cable specimen of Comparative Example 2 The oil resistance of the cable was improved due to the excessive amount of polypropylene resin contained in the silver insulation layer. However, due to the polypropylene's characteristics, the oil resistance was unstable after crosslinking, resulting in poor heat resistance. Insufficient content of ethylene vinyl acetate resin grafted with maleic anhydride included in the flexibility decreased, and the cable specimen of Comparative Example 4 was improved in flame retardant due to the excessive flame retardant content, but cracks occurred in the insulation layer during cold resistance evaluation. In the cable specimen of Comparative Example 5, a crosslinking aid was added It was confirmed that the insulation melted during the heat resistance evaluation because the cross-linking process was not conducted, and the cable specimens of Comparative Example 6 had good flexibility by adding ethylene vinyl acetate resin instead of ethylene propylene diene rubber, but the insulation resistance characteristics were not met. Oil resistance was also found to be reduced.

On the other hand, the cable specimens of Examples 1 to 3 according to the present invention satisfy all of the high insulation resistance characteristics and flexibility in conflict with the requirements of the LV 216 standard, and other properties such as oil resistance, heat resistance, and cold resistance. It was confirmed to be 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 (10)

As an insulation composition for a 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, An insulating layer formed from the insulating composition resistant volume exceeds 10 ¹³ Ω · ㎜, isolated composition. The method of claim 1, Based on 100 parts by weight of the base resin, the content of the polypropylene resin is 12 to 28 parts by weight, the content of the polyolefin elastomer is 25 to 50 parts by weight, the content of the ethylene propylene diene rubber is 20 to 50 parts by weight and the The insulating composition, characterized in that the content of ethylene vinyl acetate resin grafted maleic anhydride is 5 to 18 parts by weight. The method of claim 2, Based on 100 parts by weight of the base resin, the content of the polypropylene resin is 16 to 24 parts by weight, the content of the polyolefin elastomer is 30 to 45 parts by weight, the content of the ethylene propylene diene rubber is 30 to 40 parts by weight and the Insulation composition, characterized in that the content of ethylene vinyl acetate resin grafted maleic anhydride is 8 to 15 parts by weight. The method according to any one of claims 1 to 3, 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. The method of claim 4, wherein The ethylene propylene diene rubber has a specific gravity of 0.870 to 0.890 and a Mooney viscosity (ML1 + 4 (125 ° C)) is characterized in that 20 to 40, insulation composition. 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. The method of claim 6, 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 105 parts by weight, insulation composition. The method of claim 7, wherein The content of the flame retardant is an insulation composition, characterized in that 85 to 95 parts by weight based on 100 parts by weight of the base resin. The method of claim 6, The crosslinking aid comprises a cross-linking polyfunctional organic monomer 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. Conductor; And A cable surrounding the conductor and comprising an insulating layer formed from the insulating composition of any one of claims 1 to 3.

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