JP4358328B2 - Electrical insulating composition and electrical equipment using the same - Google Patents

Description

表１からも明らかなように、本発明にかかる絶縁性ゴム組成物は、圧縮永久歪みや引張強さなどを低下させることなく、低硬度を実現することができており、かつ、ブリードの発生もみられなかったのに対し、脂環族飽和炭化水素樹脂を過剰に配合した比較例１では、圧縮永久歪みをはじめとするすべての物性が実施例に比べ低下しており、また、プロセスオイルを配合した比較例２〜４では、特に圧縮永久歪みの低下が大きく、かつ、ブリードの発生が認められた。さらに、ＥＰゴムに代えて天然ゴムを用いた比較例５〜７では、25％低伸長応力、ヤング率、圧縮永久歪み、および体積抵抗率が低下しており、特に体積抵抗率の低下が顕著であった。
【００２３】
【発明の効果】
以上説明したように、本発明によれば、ＥＰゴムをベースとする絶縁性ゴム組成物中に、ビニルトルエンとインデンとを重合成分とする重合物を水素添加してなる脂環族飽和炭化水素樹脂を所定の割合で配合するようにしたので、低硬度で、かつ、圧縮永久歪み特性、引張強さ、ヤング率などの特性に優れ、しかも、ブリードが発生するおそれもない電気絶縁組成物およびこれを用いた高品質の電気機器を得ることができる。
【００２４】[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrical insulating composition suitable as an insulating material used for power equipment and the like, and an electrical equipment using the same.
[0002]
[Prior art]
Conventionally, rubber-based electrical insulation compositions have been widely used for various electrical equipment applications including power transmission / distribution or private-use power equipment. Such insulating rubber compositions are known in various hardnesses, and are appropriately selected and used depending on the application.
[0003]
Under these circumstances, in recent years, in cable connection devices, etc., by using a low-hardness rubber material for the cable insertion part, it will be possible to give freedom to the size of the cable that can be inserted and expand the applicable cable range. Accordingly, development of a rubber material having lower hardness is demanded.
[0004]
By the way, as a method for reducing the hardness of a rubber material, a method of blending a softener such as process oil or a plasticizer is generally known.
[0005]
However, in order to reduce the hardness, if a large amount of these is blended, the physical properties such as compression set, tensile strength, Young's modulus are reduced, and the compounding agent is in a liquid state at room temperature. There is a drawback that a so-called bleeding phenomenon occurs. The exuded compound not only contaminates the surface, but also migrates to the cable and lowers the insulation performance of the cable insulation or increases the volume resistivity of the semiconductive layer, which may result in dielectric breakdown .
[0006]
[Problems to be solved by the invention]
As described above, in recent years, there has been a demand for low hardness insulating rubber compositions for applications such as cable connection devices, but physical properties such as compression set are reduced by the conventional methods of blending softeners and plasticizers. However, there is a problem that the compounding agent bleeds to the surface, and the actual situation is that a satisfactory one has not yet been obtained.
[0007]
The present invention has been made in view of these points, and has a low hardness, there is no risk of occurrence of bleeding of the compounding agent, and the electrical insulation has good compression set, tensile strength and other characteristics. An object is to provide a composition.
[0008]
[Means for Solving the Problems]
The electrical insulating composition of the present invention is a fat obtained by hydrogenating a polymer containing vinyltoluene and indene as polymerization components per 100 parts by weight of a rubber component in an insulating rubber composition based on ethylene propylene rubber. It comprises 1 to 30 parts by weight of an aromatic cyclic saturated hydrocarbon resin.
[0009]
Moreover, the electrical equipment of the present invention is characterized by comprising an insulating component made of the electrical insulating composition.
[0010]
Examples of the ethylene propylene rubber (hereinafter referred to as EP rubber) used in the present invention include an ethylene / propylene copolymer and an ethylene / propylene / diene terpolymer. In the present invention, natural rubber (NR), styrene butadiene rubber (SBR), isoprene rubber (IR), chloroprene rubber (CR), butyl rubber, butadiene rubber (BR), acrylonitrile butadiene rubber and the like together with such EP rubber. Various other synthetic rubbers can be used in combination, but in that case, it is desirable that at least the EP rubber is blended in an amount of 50% by weight or more of the entire rubber component.
[0011]
In the present invention, the aliphatic cyclic saturated hydrocarbon resin (hereinafter referred to as alicyclic saturated hydrocarbon resin) blended with such rubber is a solid at normal temperature, and the alicyclic saturated carbonized resin. One or more kinds of hydrogen resins that are generally known can be arbitrarily selected and used. In the present invention, the softening point is preferably in the range of 25 to 160 ° C. If the softening point is less than 25 ° C, the surface may bleed. The decrease of the is insufficient. Specifically, Archon P-70, Archon P-90, Archon P-110, Archon P-125, Archon P-140 (all are trade names) manufactured by Arakawa Chemical Industries, Ltd. are preferably used. .
[0012]
In the present invention, such alicyclic saturated hydrocarbon resin is blended at a ratio of 1 to 30 parts by weight with respect to 100 parts by weight of the rubber component. If the blending amount of the alicyclic saturated hydrocarbon resin is less than 1 part by weight with respect to 100 parts by weight of the rubber component, the hardness cannot be lowered sufficiently, and conversely if it exceeds 30 parts by weight, the tensile strength, etc. Characteristics are insufficient.
[0013]
In addition to the above components, the composition of the present invention usually contains fillers such as clay and carbon black, anti-aging agents, processing aids, and other additives, which are usually blended in rubber, to inhibit the effects of the present invention. It can mix | blend in the range which does not. Moreover, softeners and plasticizers such as process oil can also be blended within a range that does not impair the effects of the present invention.
[0014]
The electrical insulating composition of the present invention is low in hardness by crosslinking by a method using an organic peroxide such as dicumyl peroxide (DCP), and further has compression set, tensile strength, Young's modulus, etc. An insulating molded product having excellent physical properties and free from the occurrence of a bleeding phenomenon of the compounding agent can be obtained.
[0015]
Thus, in the electrical insulating composition of the present invention, the blending of the alicyclic saturated hydrocarbon resin can reduce the hardness without reducing physical properties such as compression set, tensile strength, Young's modulus, etc. In addition, since the alicyclic saturated hydrocarbon resin is solid at room temperature, there is no risk of bleed on the surface like conventional process oils. Therefore, it is possible to obtain a high-quality insulating rubber molded product having a low hardness and excellent physical properties such as compression set, tensile strength, Young's modulus and the like, and without the possibility of bleeding. The reliability of electrical equipment can be improved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described by way of examples. Needless to say, the present invention is not limited to these examples.
[0017]
Examples 1-4
Aliphatic saturated hydrocarbon resin (number average molecular weight 610, softening point 70 ° C) obtained by polymerizing EP rubber (trade name Mitsui EPT3045 manufactured by Mitsui Petrochemical Co., Ltd.), vinyltoluene and indene and then hydrogenating And process oil (trade name PW-90 manufactured by Idemitsu Kosan Co., Ltd.), clay (trade name Translink Clay 37 manufactured by Engelhard), stearic acid, zinc white, cross-linking agent (dicumyl peroxide), and A crosslinking aid (triallyl isocyanurate) was uniformly mixed using a kneader at the ratio shown in Table 1 to obtain an insulating rubber composition.
[0018]
Subsequently, the obtained rubber composition was measured for 25% low elongation stress, compression set, tensile strength, elongation, hardness (JIS A), and volume resistivity in accordance with JIS K 6301. The Young's modulus was calculated based on JIS K 6386 (6) from the value of 25% low elongation stress. The compression set was obtained by crosslinking the sample sheet of the insulating rubber composition obtained by crosslinking at 160 ° C. for 40 minutes, and the other characteristics were obtained by crosslinking at 160 ° C. for 30 minutes. It is a measured value by a sample sheet.
[0019]
Further, the surface of the sample sheet was visually observed to check for the occurrence of bleeding. Judgment criteria are as follows.
[0020]
○: No bleed Δ: Partial bleed on the surface ×: Bleed almost on the entire surface Table 1 shows the measurement results.
[0021]
Comparative Examples 1-7
Moreover, as a comparative example, an example in which an alicyclic saturated hydrocarbon resin is excessively blended (Comparative Example 1), an example in which a process oil is blended instead of an alicyclic saturated hydrocarbon resin (Comparative Examples 2 to 4), EP About the example (Comparative Examples 5-7) which mix | blended natural rubber (SMR CV-60) instead of rubber | gum, the characteristic evaluation test similar to an Example was done. The results are shown together with the composition in Table 1.
[0022]
[Table 1]

As is clear from Table 1, the insulating rubber composition according to the present invention can achieve low hardness without reducing compression set, tensile strength, etc., and generation of bleeding. On the other hand, in Comparative Example 1 in which the alicyclic saturated hydrocarbon resin was excessively blended, all the physical properties including compression set were lowered as compared with the Examples, and the process oil was not used. In Comparative Examples 2 to 4 which were blended, the compression set was particularly greatly reduced, and bleeding was observed. Further, in Comparative Examples 5 to 7 using natural rubber instead of EP rubber, 25% low elongation stress, Young's modulus, compression set, and volume resistivity are lowered, and particularly, the volume resistivity is significantly lowered. Met.
[0023]
【The invention's effect】
As described above, according to the present invention, an alicyclic saturated hydrocarbon obtained by hydrogenating a polymer containing vinyltoluene and indene as polymerization components in an insulating rubber composition based on EP rubber. Since the resin is blended at a predetermined ratio, the electrical insulating composition has low hardness, excellent compression set characteristics, tensile strength, Young's modulus, and the like, and there is no risk of bleeding. A high-quality electric device using this can be obtained.
[0024]

Claims (3)

Insulating rubber composition based on ethylene propylene rubber, per 100 parts by weight of rubber component, aliphatic cyclic saturated hydrocarbon resin 1 to hydrogenated polymer containing vinyltoluene and indene as polymerization components An electrical insulating composition comprising 30 parts by weight.   The electrical insulating composition according to claim 1, wherein the aliphatic cyclic saturated hydrocarbon resin has a softening point of 25 to 160 ° C.   An electric device comprising an insulating component made of the electric insulating composition according to claim 1.