JPH0822716A - High dielectric constant insulating rubber material - Google Patents

Abstract

PURPOSE:To inexpensively provide the same high dielectric constant and insulating resistance as usual by blending prescribed carbon black in a composition mainly composed of ethylene propylene rubber or ethylene propylene diene rubber. CONSTITUTION:A composition mainly composed of ethylene propylene rubber or ethylene propylene diene rubber is used as a composition in which carbon black is blended. In this case, furnace type and thermal type carbon black is used as the carbon black, and carbon black having an average particle diameter of 40mmu to 100mmu and the surface area of 20m<2>/g to 60m<2>/g is used as the furnace type carbon black. Carbon black having an average particle diameter of 80mmu to 300mmu and the surface area of 10m<2>/g to 30m<2>/g is used as the thermal type carbon black, and a rate to be added in the composition is set in 15wt.% to 35wt.% in the furnace type, and is set in 30wt.% to 50wt.% in the thermal type.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high dielectric constant insulating rubber material used for a rubber stress cone forming an intermediate connecting portion, a terminal connecting portion or the like of a power cable.

[0002]

2. Description of the Related Art A conventional rubber stress cone is inserted with an insulating rubber member made of silicone, EPDM, neoprene rubber, etc., as disclosed in Japanese Utility Model Publication No. 2-8507. The cable is composed of a thin cylindrical member made of a high-dielectric-constant insulating rubber having elasticity between the cable-shielding layer and the cable, and the high-dielectric-constant insulating rubber is, for example, aluminum flakes or silicon in which barium titanate is dispersed, EPDM and neoprene rubber are used.

However, the high dielectric constant insulating rubber material using aluminum flakes or barium titanate as described above is expensive and has not been widely used.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides an inexpensive high-dielectric-constant insulating rubber material having the same high dielectric constant and insulation as the conventional one.
Is characterized by an average particle size of 40 m in a composition mainly composed of ethylene propylene rubber or ethylene propylene diene rubber.
μ or more and 100 mμ or less, and a surface area of 20 m ² / g or more,
Furnace-based carbon black of 60 m ² / g or less is blended in an amount of 15% by weight or more and 35% by weight or less.

A second feature of the present invention is that the composition mainly composed of ethylene propylene rubber or ethylene propylene diene rubber has an average particle size of 80 mμ or more and 300 mμ or less,
The thermal carbon black having a surface area of 10 m ² / g or more and 30 m ² / g or less is blended in an amount of 30% by weight or more and 50% by weight or less.

[0006]

The composition containing ethylene propylene rubber or ethylene propylene diene rubber as a composition containing carbon black is used as an insulating rubber member to be combined with the high dielectric constant insulating rubber of the present invention. Since a composition containing propylene diene rubber as a main component is used, it is preferable to use the same composition because of the adhesiveness of both.

Carbon black includes furnace type, thermal type and acetylene type carbon blacks.
Acetylene series cannot be put to practical use because it has a high dielectric constant (10 to 100) and an insulation resistance of 10 ⁸ Ω · cm or less.

The furnace carbon black has an average particle size of 40 mμ or more and 100 mμ or less and a surface area of 20 m ² / g.
Above, use the thing below 60m < ² > / g. Average particle size is 40mμ
Less than in obtaining a high dielectric constant (10 to 100) and the insulation resistance of 10 ⁸
Ω · cm or less, and if it exceeds 100 mμ, it is difficult to manufacture with a furnace system, and even if a product is obtained, it becomes expensive and not practical. The surface area of difficult preparation is less than 20 m ² / g, a high dielectric constant obtained the insulation resistance exceeds 60 m ² / g is
10 ⁸ Ω · cm or less.

Thermal carbon black has an average particle size of
Use those having a surface area of 80 mμ or more and 300 mμ or less and a surface area of 10 m ² / g or more and 30 m ² / g or less. If the average particle size is less than 80 mμ, it is difficult to manufacture, and if it exceeds 300 mμ, a large amount must be added to obtain a high dielectric constant, and it becomes brittle and unusable in actual use. If the surface area is less than 10 m ² / g, a large amount must be added to obtain a high dielectric constant, and it becomes brittle to endure practical use. If it exceeds 30 m ² / g, manufacturing becomes difficult.

The proportion of the carbon black added to the composition is 15% by weight or more and 35% by weight or less in the furnace system, and 30% by weight or more and 50% by weight or less in the thermal system. Carbon black cannot obtain a high dielectric constant (10 to 100) if it is less than each weight%, and if it exceeds each weight%, the insulation resistance becomes 10 ⁸ Ω · cm or less and it cannot be used for actual use. In addition to the above, process oils, antioxidants, processing aids, inorganic fillers, vulcanizing agents, etc. may be added as appropriate within the range not impairing the performance.

[0011]

EXAMPLES The compositions shown in Tables 1 and 2 were prepared and the dielectric constant and insulation resistance were measured. A dielectric constant of 10 to 100 and an insulation resistance of 10 ⁸ Ω · cm or more are required. The results are shown in Tables 1 and 2. The materials used are as follows. Ethylene propylene diene rubber: Sumitomo Chemical Esplen 30
1 Furnace-based carbon black: Tokai Carbon Seast S (average particle size 7.6 mμ, surface area 28 m ² / g) Thermal carbon black: Asahi Carbon Asahi Thermal (average particle size 150 mμ, surface area 98 m ² / g) Tokai as a comparative carbon black A carbon seed S (average particle size 27 mμ, surface area 98 m ² / g) was used. Process oils, processing aids, and vulcanizing agents are added as other compounding agents.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

As described above, according to the present invention, an inexpensive high-dielectric-constant insulating rubber material having the same high dielectric constant and insulation resistance as that of the conventional one can be obtained by using the inexpensive carbon black, and the electric power It is effective when used as a rubber molding material for cable intermediate connection and terminal connection.

Claims (2)

[Claims] 1. An average particle size of 40 in a composition mainly composed of ethylene propylene rubber or ethylene propylene diene rubber.
Furnace-based carbon black having a surface area of 20 m ² / g or more and 60 m ² / g or less of 15 μm or more and 100 mμ or less
A high-dielectric-constant insulating rubber material characterized by being blended in an amount of at least 35% by weight and at most 35% by weight. 2. A composition comprising ethylene propylene rubber or ethylene propylene diene rubber as a main component has an average particle size of 80.
mμ above, below 300Emumyu, and surface area of 10 m ² / g or more, 30 m ² / g or less of thermal based carbon black 30 wt% or more, the high dielectric constant insulating rubber, characterized in that it is formulated 50 wt% or less material.