JP2013227540A - Ep rubber composition, ep rubber material, cable and connecting part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EP rubber composition capable of forming an EP rubber material having a low tanδ even when placed under a high temperature atmosphere in a water absorbed condition while exhibiting excellent tensile elongation characteristics and low water-absorbing properties by crosslinking, and to provide an EP rubber material, a cable, and connecting parts.SOLUTION: An EP rubber composition includes: EP rubber comprising at least one selected from the group consisting of ethylene-propylene copolymers and ethylene-propylene-diene terpolymers; a surface-treated filler made by surface-treating a filler with a surface treating agent; sulfur; and an organic peroxide, wherein the EP rubber has a Mooney viscosity of larger than 8, the surface-treated filler is compounded at 60 pts.mass or more and less than 100 pts.mass based on 100 pts.mass of the EP rubber, the sulfur is compounded at 0.1-0.4 pt.mass based on 100 pts.mass of the EP rubber, and the organic peroxide is compounded at 1.5-4 pts.mass based on 100 pts.mass of the EP rubber.

Description

  The present invention relates to an EP rubber composition, an EP rubber material, a cable, and a connection component that connects a connected portion made of a cable or a device and the cable.

  EP rubber made of ethylene propylene rubber or ethylene propylene diene rubber has excellent electrical insulation properties and mechanical properties. Therefore, the insulation layer for connecting parts used for connecting cables or connecting cables to equipment, and cables Used for insulation layers.

  For such an insulating layer, an EP rubber material obtained by crosslinking an EP rubber composition containing EP rubber is used.

  For example, in the following Patent Document 1, an inorganic filler treated with a surface treatment agent having a double bond at an end is added at a ratio of 100 to 200 parts by mass with respect to 100 parts by mass of an ethylene / propylene / diene copolymer. An EP rubber composition is disclosed, and it is disclosed that a cross-linked ethylene / propylene / diene copolymer cross-linked with an organic peroxide is used as an electrical insulator of a cable.

JP 2007-99957 A

  By the way, the EP rubber material has water absorption.

  In that respect, since the crosslinked ethylene / propylene / diene copolymer described in Patent Document 1 has an inorganic filler treated with a surface treatment agent, it has low water absorption.

  However, the cross-linked ethylene / propylene / diene copolymer described in Patent Document 1 has the following problems.

  That is, when the crosslinked ethylene / propylene / diene copolymer is placed in a high temperature environment while absorbing water, the dielectric loss tangent (tan δ) of the crosslinked ethylene / propylene / diene copolymer tends to increase. That is, dielectric loss tends to occur in the crosslinked ethylene / propylene / diene copolymer. For this reason, for example, when the cable is energized, a temperature rise occurs in the crosslinked ethylene / propylene / diene copolymer which is an insulating layer, and this temperature rise further causes an increase in tan δ to cause thermal runaway. -There was a possibility of causing deterioration and dimensional change of the diene copolymer. This was remarkable when the value of tan δ exceeded 1%. Further, from the viewpoint of improving the operability and durability of connecting parts and cables, the crosslinked ethylene / propylene / diene copolymer has room for improvement in terms of tensile elongation characteristics.

  Therefore, an EP rubber composition that can form an EP rubber material having low tan δ even when placed in a high-temperature environment in a water-absorbed state while having excellent tensile elongation characteristics and low water absorption by crosslinking is desired. It was.

  The present invention has been made in view of the above circumstances, and is an EP rubber material having a low tan δ even when placed in a high-temperature environment in a water-absorbed state while having excellent tensile elongation characteristics and low water absorption by crosslinking. It is an object of the present invention to provide an EP rubber composition, an EP rubber material, a cable, and a connecting part that can form a film.

  In order to solve the above problems, the present inventor has intensively studied paying attention to the characteristics of EP rubber, the types and amounts of components to be blended in EP rubber. As a result, the present inventors have found that the above-described problems can be solved by the following invention.

  That is, the present invention is a surface treatment filling comprising an EP rubber composed of at least one selected from the group consisting of an ethylene-propylene copolymer and an ethylene-propylene-diene terpolymer, and a surface treatment with a surface treatment agent. The EP rubber has a Mooney viscosity greater than 8 and contains 60 parts by mass or more and 100 parts by mass with respect to 100 parts by mass of the EP rubber. The sulfur is blended at a ratio of 0.1 to 0.4 parts by mass with respect to 100 parts by mass of the EP rubber, and the organic peroxide is incorporated into 100 parts by mass of the EP rubber. The EP rubber composition is blended at a ratio of 1.5 to 4 parts by mass.

  According to this EP rubber composition, it is possible to form an EP rubber material having a low tan δ even when placed in a high temperature environment in a water-absorbed state while having excellent tensile elongation characteristics and low water absorption by crosslinking.

  In addition, when the compounding amount of the surface treatment filler with respect to 100 parts by mass of the EP rubber is 100 parts by mass or more, tand δ increases. On the other hand, when the blending amount of the surface treatment filler with respect to 100 parts by mass of the EP rubber is less than 60 parts by mass, the water absorption amount increases. When the amount of sulfur added to 100 parts by mass of the EP rubber is out of the above range, tand δ increases. Furthermore, when the compounding quantity of the organic peroxide with respect to 100 mass parts of EP rubber exceeds 4 mass parts, tensile elongation will become inadequate. On the other hand, the amount of water absorption increases when the blending amount of the organic peroxide with respect to 100 parts by mass of the EP rubber is less than 1.5 parts by mass. Further, when the Mooney viscosity of the EP rubber is 8 or less, tan δ increases.

  In the EP rubber composition, the EP rubber preferably has a Mooney viscosity of less than 40.

  In this case, the moldability is further improved as compared with the case where the Mooney viscosity of the EP rubber is 40 or more.

  Moreover, this invention is EP rubber material formed by radical-crosslinking the said EP rubber composition.

  According to this EP rubber material, while having excellent tensile elongation characteristics and low water absorption, it is possible to have low tan δ even when placed in a high temperature environment in a state of water absorption. As a result, thermal runaway of the EP rubber material can be sufficiently suppressed, and deterioration and dimensional change of the EP rubber material can be sufficiently suppressed.

  Moreover, this invention is a cable provided with a conductor and the insulating layer which coat | covers the said conductor, Comprising: The said insulating layer is a cable containing the said EP rubber material.

  According to this cable, the insulating layer includes the above-mentioned EP rubber material, and has an excellent tensile elongation characteristic and low water absorption, and can have a low tan δ even when placed in a high temperature environment in a water absorbed state. It becomes. For this reason, it becomes possible to fully suppress the thermal runaway of the EP rubber material, and it is possible to sufficiently suppress deterioration and dimensional change of the EP rubber material. As a result, the deterioration over time of the insulating layer can be suppressed, and the long-term reliability of the cable is improved.

  Further, the present invention is a connecting part for connecting the connected portion and the cable having a connected portion made of a device or a cable and a through-hole into which the cable is inserted, and forms a part of the through-hole. An insulating layer having a cylindrical inner peripheral surface is provided, and the insulating layer is a connection component including the EP rubber material.

  According to this connection component, the insulating layer includes an EP rubber material, and has an excellent tensile elongation property and low water absorption, and can have low tan δ even when placed in a high temperature environment in a water absorbed state. Become. Therefore, deterioration and dimensional change of the insulating layer can be sufficiently suppressed. As a result, even if the cable and the connected part are inserted and connected to the through hole, the decrease in the surface pressure on the cable and the connected part is sufficiently suppressed, and the cable and the connected part are sufficiently prevented from falling off. be able to.

  According to the present invention, an EP rubber composition capable of forming an EP rubber material having a low tan δ even when placed in a high-temperature environment in a water-absorbed state while having excellent tensile elongation characteristics and low water absorption by crosslinking, EP rubber material, cables and connecting parts are provided.

It is sectional drawing which shows 1st Embodiment of the connection component of this invention. It is sectional drawing which shows 2nd Embodiment of the connection component of this invention. It is sectional drawing which shows one Embodiment of the cable of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

[First Embodiment]
First, a first embodiment of a connection component according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a first embodiment of a connection component according to the present invention, and shows a cable connection component used for connecting a cable and a cable as a connected portion.

  As shown in FIG. 1, the cable connecting component 10 includes an internal semiconductive layer 11, an insulating layer 12 covering the internal semiconductive layer 11, and an external semiconductive layer 13 covering the insulating layer 12. Yes. The cable connecting component 10 has a through hole 14 that penetrates the inner semiconductive layer 11, the insulating layer 12, and the outer semiconductive layer 13. The through hole 14 is formed by a cylindrical inner peripheral surface 11 a of the inner semiconductive layer 11, a cylindrical inner peripheral surface 12 a of the insulating layer 12, and a cylindrical inner peripheral surface 13 a of the outer semiconductive layer 13. ing. The through hole 14 is for inserting the ends of two cables and connecting the two cables.

  Here, the insulating layer 12 includes an EP rubber material obtained by radical crosslinking of an EP rubber composition. The EP rubber composition includes an EP rubber, a surface treatment filler obtained by surface-treating the filler with a surface treatment agent, an organic peroxide, sulfur, and an organic peroxide. It has a greater Mooney viscosity, the surface treatment filler is blended in a proportion of 60 parts by weight or more and less than 100 parts by weight with respect to 100 parts by weight of the EP rubber, and sulfur is 0.1 to 100 parts by weight of the EP rubber. It mix | blends in the ratio of 0.4 mass part, and the organic peroxide is mix | blended in the ratio of 1.5-4 mass parts with respect to 100 mass parts of EP rubber.

  Here, the EP rubber composition can form an EP rubber material having a low tan δ even when placed in a high-temperature environment in a water-absorbed state while having excellent tensile elongation characteristics and low water absorption by radical crosslinking. For this reason, the insulating layer 12 containing the EP rubber material can have a low tan δ even when placed in a high-temperature environment in a water-absorbed state while having a low water absorption. Therefore, deterioration and dimensional change of the insulating layer 12 can be sufficiently suppressed. As a result, even if two cables are inserted into the through-hole 14 and connected, a decrease in the surface pressure on the cable is sufficiently suppressed, and the cable can be sufficiently prevented from falling off.

  Next, the inner semiconductive layer 11, the outer semiconductive layer 13, and the insulating layer 12 will be described in detail.

<Internal semiconductive layer and external semiconductive layer>
For the inner semiconductive layer 11 and the outer semiconductive layer 13, a semiconductive rubber material is preferably used. Examples of the semiconductive rubber material include a rubber material in which a conductive filler is blended. Here, the rubber material is preferably composed of an EP rubber material. In this case, the adhesion between the inner semiconductive layer 11 or the outer semiconductive layer 13 and the insulating layer 12 made of an EP rubber material becomes better. As the conductive filler, for example, carbon black, metal in a fibrous form, or the like can be used.

<Insulating layer>
As the material of the insulating layer 12, an EP rubber material obtained by radical crosslinking of an EP rubber composition is used.

  The EP rubber composition contains EP rubber, a surface treatment filler, sulfur, and an organic peroxide. Hereinafter, each component will be described in detail.

(EP rubber)
The EP rubber is composed of at least one of an ethylene-propylene copolymer (EPM) and an ethylene-propylene-diene terpolymer (EPT). Examples of the diene contained in the terpolymer include 5-ethylidene-2-norbornene, 1,4-hexadiene, and dicyclopentadiene. Specific examples of the EP rubber include EPT0045, EPT2060M, EPT3091, EPTX-4010M, EPT4070, EPT1045, EPT3045, EPT3092M, EPT4021, EPT1070, EPT3070, EPT4045M, EPT3062M, EPT3062M, EPT3062M, EPT3062M, EPT3062M, EPTX-3042E, EPT3090EM, manufactured by JSR Corporation EP11, EP43, EP93, EP21, EP22, EP24, EP25, EP27, EP51, EP57F, EP57C, EP103AF, EP33, EP35, EP65, EP96, EP98, Sumitomo Chemical Co., Ltd. Esprene EDPM 301A, 301, 305, 501A, 505A, 505, 502, 512F, 532 552,553,5206F, 5527F, 7456,603,6101,601F, 600F, and the like. The above EP rubbers may be used alone or in combination of two or more.

  EP rubber has a Mooney viscosity greater than 8. When the Mooney viscosity of the EP rubber is 8 or less, tan δ increases. However, the Mooney viscosity of the EP rubber is preferably less than 40. In this case, the moldability is further improved as compared with the case where the Mooney viscosity of the EP rubber is 40 or more. For this reason, when obtaining EP rubber material by shape | molding EP rubber composition, the yield of EP rubber material can be improved more.

  The Mooney viscosity of the EP rubber is preferably 15 to 35, and more preferably 20 to 30.

(Surface treatment filler)
The surface treatment filler is obtained by surface-treating a filler with a surface treatment agent.

  Examples of the filler include inorganic fillers such as clay, talc, calcium carbonate, and aluminum silicate. These can be used alone or in combination of two or more.

  Examples of the surface treatment agent include silane coupling agents and fatty acids. These can be used alone or in combination of two or more. Among these, a silane coupling agent is preferable. In this case, tan δ can be kept lower.

  Although the mass ratio of the surface treatment agent to the filler is not particularly limited, it is preferably 0.8 to 2, and more preferably 0.9 to 1.5.

  Specific examples of the surface treatment filler include Burgess KE, Burgess 2211, Burgess 5178, Burgess CB, NCC, NCC-P, Takehara Chemical Industries, Ltd. White seal WS-K, WS-KK, WS-3K, WS-810, WS-2200, manufactured by Shiraishi Calcium Co., Ltd. ST filler ST-301, ST-309, ST-501, ST-509, ST-100, ST-KE, ST-40F, PO filler PO-320-B-10, PO-220-B-10, PO-180-B-10, PO-150-B-10, PO-120- B-10, PO-10-B-10, etc. are mentioned. The surface treatment filler may be used alone or in combination of two or more.

  As described above, in the EP rubber composition, the compounding amount of the surface treatment filler is 60 parts by mass or more and less than 100 parts by mass with respect to 100 parts by mass of the EP rubber.

  When the compounding quantity of a surface treatment filler is less than 60 mass parts, the water absorption rate of the insulating layer 12 comprised with EP rubber material becomes high. On the other hand, when the blending amount of the surface treatment filler is 100 parts by mass or more, when the insulating layer 12 is placed in a high temperature environment with water absorption, tan δ is increased, and the insulating layer 12 is deteriorated and dimensional changes occur. Cables and connected parts may fall off.

  The compounding amount of the surface treatment filler with respect to 100 parts by mass of the EP rubber is preferably 60 to 80 parts by mass.

  In this case, the insulating layer 12 can have a lower tan δ even if it is placed in a high-temperature environment while absorbing water while having a lower water absorption.

(Organic peroxide)
The organic peroxide only needs to crosslink the EP rubber. Examples of such an organic peroxide include dialkyl peroxides, diacyl peroxides, ketone peroxides, hydroperoxides, Examples include peroxyketals, alkyl peresters, and percarbonates.

  Specific examples of the organic peroxide as described above include dicumyl peroxide (DCP), 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5- ( t-butylperoxy) -3-hexyne, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5- Dimethyl-2,5-dibenzoylperoxyhexane, n-butyl-4,4-bis (t-butylperoxy) valerate, t-butylperoxybenzoate, 1,4-bis [(t-butylperoxy ) Isopropyl] benzene, t-butylcumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, di-t-butyl Peroxide, and the like. These may be used alone or in combination of two or more.

  The compounding quantity of an organic peroxide is 1.5-4.0 mass parts with respect to 100 mass parts of EP rubber. When the blending amount of the organic peroxide with respect to 100 parts by mass of the EP rubber exceeds 4 parts by mass, the tensile elongation becomes insufficient. On the other hand, the amount of water absorption increases when the blending amount of the organic peroxide with respect to 100 parts by mass of the EP rubber is less than 1.5 parts by mass.

  The amount of the organic peroxide is more preferably 2.0 to 3.5 parts by mass with respect to 100 parts by mass of the EP rubber.

(sulfur)
The EP rubber composition contains sulfur. Sulfur is also used to crosslink the EP rubber, like the organic peroxide. The compounding quantity of sulfur is 0.1-0.4 mass part with respect to 100 mass parts of EP rubber. When the compounding amount of sulfur with respect to 100 parts by mass of the EP rubber is out of the range of 0.1 to 0.4 parts by mass, tand δ increases.

  The amount of sulfur is preferably 0.2 to 0.3 parts by mass with respect to 100 parts by mass of the EP rubber.

  In addition to the EP rubber, surface treatment filler, organic peroxide and sulfur, the EP rubber composition may contain a crosslinking aid, carbon, softening oil, lubricant, anti-aging agent, stabilizer and the like. Good.

  The EP rubber composition can be obtained by blending the above-described components and melt-kneading them using a Banbury mixer, a pressure kneader, a twin screw extruder, a buscon kneader, a Henschel mixer, a roll kneader or the like.

  The connection component 10 can be obtained by injection molding each member. At this time, the EP rubber composition is usually crosslinked at a temperature of 160 to 260 ° C., preferably 170 to 200 ° C.

[Second Embodiment]
Next, a second embodiment of the connection component according to the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a second embodiment of a connection component according to the present invention, and shows a device direct connection terminal component used for connecting a cable and a device as a connected portion.

  As shown in FIG. 2, the device direct connection terminal component 20 includes an L-shaped internal semiconductive layer 21, an insulating layer 22 covering the internal semiconductive layer 21, and an external semiconductive layer 23 covering the insulating layer 22. And. The device direct connection terminal component 20 has an internal semiconductive layer 21, and a through hole 24 that penetrates the insulating layer 22 and the external semiconductive layer 23. The device direct connection terminal component 20 has a through hole 24 that penetrates the internal semiconductive layer 21, the insulating layer 22, and the external semiconductive layer 23. The through hole 24 is formed by a cylindrical inner peripheral surface 21 a of the inner semiconductive layer 21, a cylindrical inner peripheral surface 22 a of the insulating layer 22, and a cylindrical inner peripheral surface 23 a of the outer semiconductive layer 23. ing. The through hole 24 is for inserting a cable and a terminal included in the device and connecting the tip of the cable and the terminal of the device.

  Here, the insulating layer 22 includes an EP rubber material obtained by radical crosslinking of the EP rubber composition described in the first embodiment. Here, the EP rubber composition can form an EP rubber material having a low tan δ even when placed in a high-temperature environment in a water-absorbed state while having a low water absorption by radical crosslinking. For this reason, the insulating layer 22 containing the EP rubber material can have a low tan δ even when placed in a high-temperature environment while absorbing water while having a low water absorption. Therefore, deterioration and dimensional change of the insulating layer 22 can be sufficiently suppressed. As a result, even if the cable and the connected portion are inserted into the through hole 24 and connected, the reduction of the surface pressure to the tip of the cable and the terminal included in the device is sufficiently suppressed, and the cable and the connected portion are not dropped. It can be sufficiently prevented.

  The internal semiconductive layer 21 is made of the same material as the internal semiconductive layer 11 of the first embodiment, and the external semiconductive layer 23 is made of the same material as the external semiconductive layer 13 of the first embodiment. The

[Third Embodiment]
Next, an embodiment of the cable of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view showing an embodiment of a cable according to the present invention. As shown in FIG. 3, the cable 30 includes a conductor 35, an internal semiconductive layer 31 that covers the conductor 35, an insulating layer 32 that covers the internal semiconductive layer 31, and an external semiconductive that covers the insulator layer 32. Layer 33.

  Here, the insulating layer 32 is made of an EP rubber material obtained by radical crosslinking of the EP rubber composition described in the first embodiment. Here, the EP rubber composition can form an EP rubber material having a low tan δ even when placed in a high-temperature environment in a water-absorbed state while having excellent tensile elongation characteristics and low water absorption by radical crosslinking. For this reason, the insulating layer 32 containing the EP rubber material can have a low tan δ even when placed in a high-temperature environment while absorbing water while having a low water absorption. Therefore, deterioration and dimensional change of the insulating layer 32 can be sufficiently suppressed. As a result, 32 years of deterioration of the insulating layer can be suppressed, so that the long-term reliability of the cable 30 is improved.

  As the conductor 35, a metal wire such as a copper wire, a copper alloy wire, or an aluminum wire can be used. Further, the conductor 35 may be formed by plating the surface of the metal wire with tin, silver or the like. The conductor 35 may be a single wire conductor or a stranded wire conductor.

  The internal semiconductive layer 31 is made of the same material as the internal semiconductive layer 11 of the first embodiment, and the external semiconductive layer 33 is made of the same material as the external semiconductive layer 13 of the first embodiment. The

  Hereinafter, although the content of the present invention will be described more specifically with reference to examples and comparative examples, the present invention is not limited to the following examples. The raw materials of the EP rubber composition used in Examples and Comparative Examples are as follows.

(A) EP rubber (1) EP rubber-1
Ethylene-propylene-diene rubber (trade name: “EPT4021”, ML1 + 4 (100 ° C.): 24, manufactured by Mitsui Chemicals, Inc.)
(2) EP rubber-2
Ethylene-propylene-diene rubber (trade name “EPT 8030-M”, ML1 + 4 (100 ° C.): 32, manufactured by Mitsui Chemicals, Inc.)
(3) EP rubber-3
Ethylene-propylene-diene rubber (trade name “EPT X-4010”, ML1 + 4 (100 ° C.): 8, manufactured by Mitsui Chemicals, Inc.)
(B) Filler (1) Surface treatment filler Aluminum silicate surface treated with a silane coupling agent (trade name “Burges KE”, manufactured by Burgess Pigment Co., Ltd.)
(2) Untreated surface filler-2
(Brand name “Dixie Clay”, manufactured by Dixie Rubber Pit)
(C) Organic peroxide dicumyl peroxide (DCP, trade name “Park Mill D”, manufactured by NOF Corporation)
α, α'-di (t-butylperoxy) diisopropylbenzene (P, trade name "Perbutyl P", manufactured by NOF Corporation)
(D) Sulfur product name “Sedimented Sulfur”, manufactured by Tsurumi Chemical Co., Ltd. (E) Carbon Carbon Black (trade name “Asahi # 35”, manufactured by Asahi Carbon Co., Ltd.)
(F) Softened paraffinic oil (trade name “Samper # 2280”, manufactured by Nippon San Oil Co., Ltd.)
(G) Lubricant (1) Lubricant-1
Product name “High Wax 220P”, manufactured by Mitsui Chemicals, Inc. (2) Lubricant-2
Zinc stearate (trade name “Zinc stearate”, manufactured by Kawamura Kasei Co., Ltd.)
(H) Anti-aging agent (1) Anti-aging agent-1
2-mercaptobenzimidazole (trade name “NOCRACK MB”, manufactured by Ouchi Shinsei Chemical Co., Ltd.)
(2) Anti-aging agent-2
Pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (trade name “Irganox 1010”, manufactured by BASF Corporation)
(I) Stabilizer Zinc Hana (trade name “Zinc Oxide 2”, manufactured by Sakai Chemical Industry Co., Ltd.)

(Examples 1-19 and Comparative Examples 1-12)
The above components (A) to (I) were blended in the ratios shown in Tables 1 to 4, and melt kneaded at 120 ° C. using a Banbury mixer to obtain an EP rubber composition. While this EP rubber composition was molded into a size of 20 cm × 20 cm × 0.2 cm using a compression press, it was crosslinked by heating at 160 ° C. for 40 minutes to obtain a test piece of EP rubber material. In addition, in Tables 1-4, the unit of the compounding quantity of each component of (A)-(I) is a mass part.

[Characteristic evaluation]
(1) Water Absorption The water absorption rate (water concentration) of the test pieces made of the EP rubber materials of Examples 1 to 19 and Comparative Examples 1 to 12 was measured. The water absorption, that is, the water content (% by mass) in the test piece was measured by the Karl Fischer method (coulometric titration method). Specifically, the test piece was heated at 200 ° C. to extract water for 15 minutes, and then the water content was measured by dropping a Karl Fischer reagent. The water absorption rate was measured in the same manner as described above even after the test piece was immersed in warm water at 80 ° C. for 14 days. The results are shown in Tables 1-4. In addition, the unit of water absorption is mass ppm. Tables 1 to 4 also show the ratio of the water absorption after immersion to the water absorption before immersion (water absorption ratio). The acceptance criteria for water absorption were as follows.

Pass: Water absorption ratio is 10 or less

(2) tan δ
About the test piece test piece which consists of EP rubber material of Examples 1-19 and Comparative Examples 1-12, tan-delta before being immersed in 80 degreeC hot water, and tan-delta after being immersed in 80 degreeC hot water for 7 days Was measured. Tan δ was measured at each temperature shown in Tables 1 to 4. The results are shown in Tables 1-4. Note that tan δ was formed by forming the EP rubber materials of Examples 1 to 19 and Comparative Examples 1 to 12 into a sheet shape of 10 cm × 10 cm × 0.2 cm, and this sheet was electrically insulated material C & tan δ measuring instrument “DAC-IM -D6 "(product name, manufactured by Soken Denki Co., Ltd.). The value of tan δ is displayed as a numerator value when the denominator is 100, and the unit is “%”. Furthermore, the acceptance criteria for tan δ were as follows.

Pass: Tan δ at 90 ° C after immersion in hot water at 80 ° C for 7 days is 0.478% or less

(3) Formability The moldability was determined using the Mooney viscosity (ML1 + 4) of the EP rubber compositions of Examples 1 to 19 and Comparative Examples 1 to 12 as an index. Mooney viscosity was measured based on JISK6300-1. The results are shown in Tables 1-4.

(4) Tensile elongation characteristics The tensile elongation characteristics were measured using the tensile elongation at 25 ° C measured according to JISK6251 for the test pieces made of the EP rubber materials of Examples 1 to 19 and Comparative Examples 1 to 12. The results are shown in Tables 1-4. The acceptance criteria for the tensile elongation characteristics were as follows.

Pass: The tensile elongation is over 350%

  From the results shown in Tables 1 to 4, it was found that the EP rubber materials of Examples 1 to 19 satisfied the acceptance criteria in terms of water absorption, tan δ, and tensile elongation. On the other hand, it was found that the EP rubber materials of Comparative Examples 1 to 12 did not satisfy the acceptance criteria in terms of either water absorption or tan δ.

  As described above, the EP rubber composition of the present invention forms an EP rubber material having a low tan δ even when placed in a high-temperature environment in a water-absorbed state while having excellent tensile elongation characteristics and low water absorption by crosslinking. It was confirmed that it was possible.

10 ... Cable connection parts (connection parts)
12, 22, 32 ... Insulating layer 20 ... Terminal direct connection parts (connection parts)
30 ... Cable 35 ... Conductor

That is, the present invention is a surface treatment filling comprising an EP rubber composed of at least one selected from the group consisting of an ethylene-propylene copolymer and an ethylene-propylene-diene terpolymer, and a surface treatment with a surface treatment agent. The EP rubber has a Mooney viscosity greater than 8 (ML1 + 4) , and the surface treatment filler is 60 parts by mass with respect to 100 parts by mass of the EP rubber. More than 100 parts by mass is blended, the sulfur is blended at a ratio of 0.1 to 0.4 parts by mass with respect to 100 parts by mass of the EP rubber, and the organic peroxide is blended with the EP rubber 100. EP rubber composition which is blended at a ratio of 1.5 to 4 parts by mass with respect to parts by mass , and wherein the Mooney viscosity is a value measured at 100 ° C. based on JIS K6300-1 . It is.

In addition, when the compounding amount of the surface treatment filler with respect to 100 parts by mass of the EP rubber is 100 parts by mass or more, tand δ increases. On the other hand, when the blending amount of the surface treatment filler with respect to 100 parts by mass of the EP rubber is less than 60 parts by mass, the water absorption amount increases. When the amount of sulfur added to 100 parts by mass of the EP rubber is out of the above range, tand δ increases. Furthermore, when the compounding quantity of the organic peroxide with respect to 100 mass parts of EP rubber exceeds 4 mass parts, tensile elongation will become inadequate. On the other hand, the amount of water absorption increases when the blending amount of the organic peroxide with respect to 100 parts by mass of the EP rubber is less than 1.5 parts by mass. Further, when the Mooney viscosity of the EP rubber is 8 (ML1 + 4) or less, tan δ increases.

In the EP rubber composition, the EP rubber preferably has a Mooney viscosity of less than 40 (ML1 + 4) .

In this case, the moldability is further improved as compared with the case where the Mooney viscosity of the EP rubber is 40 (ML1 + 4) or more.
In the EP rubber composition, it is preferable that the sulfur is blended at a ratio of 0.1 to 0.25 parts by mass with respect to 100 parts by mass of the EP rubber.

Claims (5)

An EP rubber composed of at least one selected from the group consisting of ethylene-propylene copolymers and ethylene-propylene-diene terpolymers;
A surface treatment filler obtained by surface-treating a filler with a surface treatment agent;
Sulfur and
Organic peroxides,
The EP rubber has a Mooney viscosity greater than 8,
The surface treatment filler is blended at a ratio of 60 parts by weight or more and less than 100 parts by weight with respect to 100 parts by weight of the EP rubber,
The sulfur is blended at a ratio of 0.1 to 0.4 parts by mass with respect to 100 parts by mass of the EP rubber,
An EP rubber composition in which the organic peroxide is blended at a ratio of 1.5 to 4 parts by mass with respect to 100 parts by mass of the EP rubber.   The EP rubber composition of claim 1, wherein the EP rubber has a Mooney viscosity of less than 40.   An EP rubber material obtained by radical crosslinking of the EP rubber composition according to claim 1. Conductors,
A cable comprising an insulating layer covering the conductor,
A cable wherein the insulating layer comprises the EP rubber material according to claim 3. It has a through-hole into which a connected portion made of a device or a cable and a cable are inserted, and is a connecting component that connects the connected portion and the cable,
An insulating layer having a cylindrical inner peripheral surface forming a part of the through hole;
A connecting part, wherein the insulating layer comprises the EP rubber material according to claim 3.

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