JP2015153514A - Highly dielectric composition for cable connection part and cable connection part using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition which has a high dielectric constant, high insulating properties, good mechanical characteristics, and good processability, and to provide a cable connection part using such a composition.SOLUTION: The highly dielectric composition for a cable connection part contains 20-60 pts.mass of a tetrapod-like zinc oxide formed of a needle single crystal and 30-70 pts.mass of carbon black, based on 100 pts.mass of an ethylene-propylene-diene terpolymer. The cable connection part has an electric field relaxation layer comprising such a highly dielectric composition.

Description

  The present invention relates to a high dielectric composition suitable for forming an electric field relaxation layer of a cable connection portion, and a cable connection portion using the same.

  In the middle connection part and terminal connection part of rubber / plastic insulation power cables such as CV cables (cross-linked polyethylene insulated power cables), as a measure for electric field relaxation at the end of the outer semiconductive layer (or shielding layer) of the cut cable An electric field relaxation layer made of a dielectric having a dielectric constant higher than that of an insulator is provided. This is based on the principle that equipotential lines and electric stress refract when passing through substances having different dielectric constants.

  Conventionally, this electric field relaxation layer is generally formed by blending an insulating rubber / plastic composition with a high dielectric constant filler such as carbon black, zinc oxide, barium titanate (for example, , See Patent Document 1).

  However, in such a conventional composition, when the blending amount of the high dielectric constant filler is increased in order to increase the dielectric constant, the insulation, which is an important required characteristic for the electric field relaxation layer, is lowered together with the dielectric constant. There was a problem that the mechanical properties and workability also deteriorated. For this reason, a composition having a high dielectric constant, high insulating properties, and excellent mechanical properties and workability has not yet been obtained.

JP 59-162708 A

  The present invention has been made to solve such problems of the prior art, a composition having a high dielectric constant, a high insulating property, and good mechanical properties and workability, and such a high An object of the present invention is to provide a highly reliable cable connection portion using a dielectric composition.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a specific ethylene-based terpolymer rubber has a needle-like unit having a specific three-dimensional shape such as a tetrapot with carbon black. By blending zinc oxide consisting of crystals, it is possible to obtain a composition having high dielectric constant, high insulation, good mechanical properties and workability, and a cable connection portion using this composition. The headline and the present invention were completed.

  That is, in order to solve the above-mentioned object, the invention described in claim 1 is based on 100 parts by mass of an ethylene / propylene / diene terpolymer. It is a high dielectric composition for cable connection parts characterized by containing a mass part and 30-70 mass parts of carbon black.

  The invention described in claim 2 is the high dielectric composition for a cable connection part according to claim 1, wherein the diene component of the ethylene / propylene / diene terpolymer is ethylidene norbornene. It is a high dielectric composition for cable connection parts.

  The invention described in claim 3 is the high dielectric composition for a cable connection part according to claim 1 or 2, wherein the tetrapot zinc oxide is added to 100 parts by mass of the ethylene / propylene / diene terpolymer. 30 to 50 parts by mass A high dielectric composition for cable connection parts.

  According to a fourth aspect of the present invention, there is provided a high dielectric composition for a cable connection portion according to any one of the first to third aspects of the present invention, wherein 100 parts by mass of the ethylene / propylene / diene terpolymer is carbon. A high dielectric composition for cable connection parts, comprising 40 to 60 parts by mass of black.

  The invention described in claim 5 is the high dielectric composition for a cable connection part according to any one of claims 1 to 4, wherein the tetrapot-like zinc oxide has an average fiber length (needle portion) of 5 to 5. It is a high dielectric composition for cable connection parts characterized by being of 15 μm.

The invention described in claim 6 is the high dielectric composition for a cable connection part according to any one of claims 1 to 5, wherein the relative dielectric constant (JIS K 6249) is 5.0 or more and 23 A high dielectric composition for cable connection parts, wherein the volume resistivity at ° C. is 1.0 × 10 ^{8 to} 1.0 × 10 ¹⁵ Ω · cm.

The invention described in claim 7 is the high dielectric composition for a cable connection part according to any one of claims 1 to 5, wherein the relative dielectric constant (JIS K 6249) is 5.0 or more and 23 A high dielectric composition for cable connection parts, wherein the volume resistivity at 1.0 ° C. is 1.0 × 10 ^{10 to} 1.0 × 10 ¹³ Ω · cm.

  The invention described in claim 8 is a cable connection portion having an electric field relaxation layer made of the high dielectric composition according to any one of claims 1 to 7.

  According to the present invention, a composition having a high dielectric constant, high insulation properties, and good mechanical properties and workability, and a highly reliable cable connection portion using such a high dielectric composition Can be obtained.

It is sectional drawing which shows the principal part structure of one Embodiment of the cave connection part of this invention.

  Embodiments of the present invention will be described below.

First, the high dielectric composition for a cable connection part of the present invention and the physical properties of this composition will be described. In addition, the measuring method of a physical property is as follows.
(A) Dielectric constant and dielectric loss tangent Measured according to JIS K 6249 (test voltage 250V)
(B) Volume resistivity Measured by the double ring electrode method specified in JIS K 6271 (c) Tensile properties (100% modulus, tensile strength, elongation)

  The high dielectric composition for a cable connection portion of the present invention (hereinafter also simply referred to as “high dielectric composition”) includes (A) an ethylene / propylene / diene terpolymer and (B) an acicular single crystal. It contains tetrapot-like zinc oxide composed of a body and (C) conductive carbon black.

  Examples of the diene component in the ethylene / propylene / diene terpolymer of component (A) used in the high dielectric composition of the present invention include ethylidene norbornene (ENB), vinyl norborn, enedicyclopentadiene, and 1,4-hexadiene. Etc. Among these, ethylidene norbornene is preferable from the viewpoint of reliability. The content of the diene component in the ethylene / propylene / diene terpolymer is not particularly limited, but is preferably 15% by mass or less, and if it exceeds 15% by mass, the workability is lowered. The diene component content is more preferably in the range of 1 to 12% by mass. Moreover, although it does not specifically limit about each unit component of ethylene and propylene, it is preferable from a point of workability that ethylene content is 45-70 mass%.

  An example of a commercially available product suitable as the ethylene / propylene / diene terpolymer of component (A) is Esprene 501A (ethylene content: 52 wt%, diene content: 4.0, manufactured by Sumitomo Chemical Co., Ltd.). Wt%, diene component: ENB), Esprene 502 (ethylene content: 56 wt%, diene content: 4.0 wt%, diene component: ENB), EPT # 3045 (ethylene content) manufactured by Mitsui Chemicals, Inc. Amount: 56 wt%, diene content: 4.7 wt%, diene component: ENB), EPT # 4045 (ethylene content: 45 wt%, diene content: 7.6 wt%, diene component: ENB) EPT # 3070 (ethylene content: 58% by weight, diene content: 4.7% by weight, diene component: ENB), Nodel IP4520 (ethylene content by Dow Chemical) 58% by weight, diene content: 4.7% by weight, diene component: ENB), Nodel IP4640 (ethylene content: 55% by weight, diene content: 4.9% by weight, diene component: ENB) (above, Product name).

  In the present invention, a polymer other than the above-mentioned ethylene / propylene / diene terpolymer may be contained within a range not impairing the effects of the present invention. Examples of such polymers include polyethylene such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), etc. Polypropylene (PP); Polyisobutylene; Vinyl esters such as ethylene, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl salicylate, vinyl cyclohexanecarboxylate Copolymerized ethylene / vinyl ester copolymer; ethylene, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, acrylic acid -Ethylene hexyl, methyl methacrylate, ethyl methacrylate, isobutyl acrylate, dimethyl maleate, ethylene (meth) acrylate copolymer copolymerized with unsaturated carboxylic acid ester such as diethyl maleate; ethylene and acrylic Ethylene / unsaturated carboxylic acid copolymerized with unsaturated carboxylic acid such as acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, monomethyl maleate and monoethyl maleate Polymer: ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1- Tetradecene, 1-pentadecene, 1-hexadecene, 1-hept Ethylene / α-olefin copolymer obtained by copolymerization of α-olefin such as decene, 1-nonadecene, 1-eicocene, 4-methyl-1-pentene; isobutylene / isoprene copolymer; ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1- Examples include α-olefins such as heptadecene, 1-nonadecene, 1-eicosene and 4-methyl-1-pentene, and copolymers obtained by copolymerizing the above-described diene components.

  The component (B) zinc oxide used in the high dielectric composition of the present invention is composed of a needle-like single crystal having a special three-dimensional shape called tetrapot, which increases the relative dielectric constant and has an insulating property. In particular, from the viewpoint of improving the average fiber length of the needle-like portion is preferably in the range of 5 to 15 μm. Examples of commercially available products suitable as the tetrapot-like zinc oxide of component (C) include, for example, Panatetra WZ-0501 and Panatetra WZ-0511 manufactured by Amtec Co., Ltd. having an average fiber length of the needle-like portion of 10 μm (above, products Name).

  The blending amount of this (B) component tetrapot-like zinc oxide is 20 to 60 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the (A) component ethylene / propylene / diene terpolymer. Part, more preferably 35 to 45 parts by mass. If the blending amount is less than 20 parts by mass, the relative dielectric constant becomes small and the volume resistivity becomes too large, so that the electric field relaxation effect at the cable connecting part cannot be sufficiently obtained. Moreover, when it exceeds 60 mass parts, while insulating property will fall (volume resistivity will fall), mechanical characteristics and workability will also fall.

  In the present invention, if necessary, fine particles of zinc oxide conventionally used in this type of rubber composition, for example, one type of zinc oxide, two types of zinc oxide, three types of zinc oxide, etc. You may use with pot-shaped zinc oxide. However, when used in combination, the total amount with the tetrapotted zinc oxide should not exceed 60 parts by mass with respect to 100 parts by mass of the ethylene / propylene / diene terpolymer of component (A). Is preferable from the viewpoints of insulation, mechanical properties, workability, and the like.

  Examples of component (C) carbon black used in the high dielectric composition of the present invention include furnace black, thermal black, and channel black. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The blending amount of the carbon black of component (C) is 30 to 70 parts by weight, preferably 40 to 60 parts by weight, based on 100 parts by weight of the ethylene / propylene / diene terpolymer of component (A). Preferably it is 45-55 mass parts. When the blending amount is less than 30 parts by mass, the relative dielectric constant becomes small, and the electric field relaxation effect at the cable connection part cannot be obtained sufficiently. Moreover, when it exceeds 70 mass parts, while insulating property will fall (volume low efficiency will fall), mechanical characteristics and workability will also fall.

  The high dielectric composition of the present invention crosslinks (vulcanizes) the polymer component after coating or molding. As the crosslinking method, a chemical vulcanization method in which a crosslinking agent is added to the composition in advance and crosslinked after coating or molding, an electron beam crosslinking method by electron beam irradiation, or the like can be used. A chemical crosslinking method using an oxide is particularly suitable.

  Examples of the organic peroxide include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, and 2,5-dimethyl-2. , 5-Di- (tert-butylperoxy) hexyne-3, di- (tert-butylperoxy) diisopropylbenzene, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert -Butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl oxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxy Benzoate, tert-butyl peroxyisopropyl carbonate, diaceti Luperoxide, lauroyl peroxide, tert-butylcumyl peroxide and the like are used. These organic peroxides may be used alone or in combination of two or more. Among the organic peroxides, among them, dicumyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 1,1-bis (tert-butylperoxy) -3 , 3,5-trimethylcyclohexane and 1,3-bis (tert-butylperoxyisopropyl) benzene are preferable from the viewpoint of processability, and dicumyl peroxide is particularly preferable.

  The organic peroxide is usually used in an amount of 1 to 5 parts by weight, preferably 2 to 4 parts by weight, based on 100 parts by weight of the ethylene / propylene / diene terpolymer. When the blending amount of the organic peroxide is less than 1 part by mass, mechanical properties and heat aging resistance are lowered, and compression set may be increased. If it exceeds 5 parts by mass, the scorch time is shortened and the hardness is increased.

  In addition to the components described above, the high dielectric composition of the present invention may further include an inorganic filler other than zinc oxide, a processing aid, and a crosslinking aid, as long as the effects of the present invention are not impaired. , Flame retardants, antioxidants, anti-aging agents, ultraviolet absorbers, neutralizers, softeners, plasticizers, dispersants, lubricants, and other additives can be blended.

  Specifically, for example, various process oils can be used as a softening agent. The process oil is preferably a paraffinic process oil. Examples of commercially available paraffinic process oils include PW-90, PW-150, PW-380 (above, trade names) manufactured by Idemitsu Kosan Co., Ltd., and the like. The process oil is usually used in an amount of 10 to 30 parts by mass, preferably 15 to 25 parts by mass, per 100 parts by mass of the ethylene / propylene / diene terpolymer of component (A). If the blending amount of the process oil is less than 10 parts by mass, the Mooney viscosity and hardness increase, and if it exceeds 30 parts by mass, the mechanical properties and the like are deteriorated.

  The highly dielectric composition of the present invention can be easily produced by uniformly mixing the above components using a conventional kneader such as a Banbury mixer, tumbler, pressure kneader, kneading extruder, mixing roller, or the like. Can do.

For the purposes of the present invention, the high dielectric composition of the present invention has (a) a relative dielectric constant (23 ° C.) of 5.0 or higher and (b) a volume resistivity (23 ° C.) of 1.0. X10 ⁸ Ω · cm or more is preferable. More preferably, (a) the relative dielectric constant (23 ° C.) is in the range of 5.0 to 70.0, and (b) the volume resistivity (23 ° C.) is 1.0 × 10 ^{8 to} 1.0 × 10. ¹⁵ Ω · cm. Even more preferably, (a) the relative dielectric constant (23 ° C.) is in the range of 9.0 to 70.0, and (b) the volume resistivity (23 ° C.) is 1.0 × 10 ^{10 to} 1.0 ×. 10 ¹³ Ω · cm.

  In addition, the high dielectric composition of the present invention has (c) tensile properties with a 100% modulus of 3.0 to 8.0 MPa, a tensile strength of 10.0 to 20.0 MPa, and an elongation of 200 to 500. %, 100% modulus is 4.0 to 7.0 MPa, tensile strength is 16.0 to 20.0 MPa, and elongation is more preferably 300 to 450%.

Next, the cable connection part of this invention using the said high dielectric composition for cable connection parts is demonstrated.
The cable connection portion of the present invention is formed by extrusion coating the composition prepared by the above-described method across a required portion of the stepped cable connection end, for example, from the outer semiconductive layer onto the cable insulator, or a tape. It is manufactured by winding or mounting a shape formed into a tube shape or a tube shape. As described above, the composition is crosslinked after coating or molding.

FIG. 1 is a cross-sectional view showing an example of a cable connecting portion of the present invention.
As shown in FIG. 1, in the cable connection portion 10 of the present embodiment, an electric field relaxation layer 13 is formed from the insulator 11 at the cable end exposed by stripping to the outer semiconductive layer 12. ing. Further, a connection terminal 14 is attached to the kale conductor (not shown), and a grounding fitting 16 is attached on the outer semiconductive layer 12 near the cable sheath 15. Further, a semiconductive fusion tape 17 such as an ACP tape is wound around the outer periphery of the grounding metal fitting 16, and a protection made of a normal temperature shrinkable tube or the like straddling the connection terminal 14 over the cable sheath 15 so as to protect them. A tube 18 is attached. In FIG. 1, 19 is an insulating tape.
And in this cable connection part 10, the electric field relaxation layer 13 is formed with the high dielectric composition for cable connection parts mentioned above.

  In the cable connection portion configured as described above, the electric field relaxation layer 13 is formed of a high dielectric rubber composition having a high dielectric constant, excellent insulating properties, and excellent mechanical properties and workability. In addition to being excellent in electrical characteristics, such excellent electrical characteristics can be stably maintained over a long period of time.

  In addition, although the said embodiment is an example which applied the cable connection part of this invention to the indoor cable termination connection part, this invention is not limited to such an example, An outdoor cable termination connection part is used. First, the present invention can be widely applied to various cable connection parts such as an intermediate connection part for connecting cables and a branch connection part used for branching a cable from a trunk cable.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. The components used in Examples and Comparative Examples are as follows.
・ Ethylene / propylene / diene terpolymer (EPDM):
Product name EPT # 3045 manufactured by Mitsui Chemicals, Inc.
-Zinc oxide A:
Product name manufactured by Amtec Co., Ltd. Panatetra WZ-0501
-Zinc oxide B: Zinc oxide 2 types, manufactured by Shodo Chemical Industry Co., Ltd. Trade name Zinc oxide 2 types-Carbon black:
Asahi Carbon Co., Ltd. Product name Asahi 50U
・ Process oil:
Idemitsu Kosan Co., Ltd. Product Name Diana Process Oil PW-90
・ Antioxidant: 2-mercaptobenzimidazole, manufactured by Ouchi Shinsei Chemical Co., Ltd.
・ Lubricant:
Product name: Stearic acid 300, manufactured by Shin Nippon Rika Co., Ltd.
・ Vulcanizing agent: Dicumyl peroxide;
Kayaku Mill D-40C (40% diluted product) manufactured by Kayaku Akzo Co., Ltd.
・ Vulcanization aid: 1,3,5-triallyl isocyanurate (TAIC)
Nippon Kasei Co., Ltd. Product Name

Example 1
EPDM 100 parts by mass, zinc oxide A 22.0 parts by mass, carbon black 32.0 parts by mass, process oil 30.0 parts by mass, antioxidant 1.5 parts by mass, lubricant 1.0 part by mass, vulcanizing agent 2.8 Mass parts and 1.5 parts by mass of the vulcanization aid were uniformly kneaded using a pressure kneader to prepare a high dielectric composition for cable connection parts.

Examples 2-8, Comparative Examples 1-5
A high dielectric composition for a cable connection part was prepared in the same manner as in Example 1 except that the blending components and blending amounts were changed as shown in Table 1.

About the high dielectric composition for cable connection parts obtained by each said Example and each comparative example, various characteristics were evaluated by the method shown below.
[Mooney viscosity]
Based on the Mooney viscosity test of JIS K 6300-1, the measurement was performed at a measurement temperature of 100 ° C. using an L-shaped rotor.
[Scorch time _t 5]
Based on the Mooney scorch test of JIS K 6300-1, the measurement was performed at 125 ° C. using an L-shaped rotor.
[density]
It was measured by the A method defined in JIS K 6268.
[Hardness]
A sheet having a thickness of about 12 mm prepared by press molding the high dielectric composition for cable connection at 180 ° C. for 7 minutes was measured with a type A durometer of JIS K 6253.
[100% modulus, tensile strength, elongation]
A tensile test (dumbbell-shaped No. 3 test piece) specified in JIS K 6251 was performed on a sheet having a thickness of about 2 mm produced in the same manner as described above, and the tensile stress, tensile strength, and elongation at 100% elongation were measured. .
[Volume resistivity]
About the sheet | seat of about 2 mm thickness produced similarly to the above, it measured by the double ring electrode method prescribed | regulated to JISK6271. The measurement was performed at each temperature of 23 ° C. and 90 ° C.
[Relative permittivity, dissipation factor]
A sheet having a thickness of about 2 mm produced in the same manner as described above was measured according to JIS K 6249 (test voltage 250 V).

  These results are shown in the lower column of Table 1.

As can be seen from Table 1, the high dielectric composition for cable connection part according to the example is a tetrapotted zinc oxide (zinc oxide A) 20 with respect to 100 parts by mass of ethylene / propylene / diene terpolymer. By containing -60 parts by mass and 30-70 parts by mass of carbon black, relative dielectric constant, volume resistivity, processability (Mooney viscosity, Mooney scorch time), mechanical properties (100% modulus, tensile strength, Good results were obtained in (Elongation) (Examples 1-8).
Further, by setting the content of tetrapotted zinc oxide (zinc oxide A) to 30 to 50 parts by mass with respect to 100 parts by mass of the ethylene / propylene / diene terpolymer, the tensile strength and volume resistivity are better. Results were obtained (Examples 3-6).
Furthermore, by setting the content of carbon black to 40 to 60 parts by mass, better results in relative permittivity were obtained (Examples 4 and 5).

  DESCRIPTION OF SYMBOLS 10 ... Cable connection part, 11 ... Cable insulator, 12 ... Cable external semiconductive layer, 13 ... Electric field relaxation layer.

Claims (8)

  It contains 20 to 60 parts by mass of tetrapotted zinc oxide composed of a needle-like single crystal and 30 to 70 parts by mass of carbon black with respect to 100 parts by mass of an ethylene / propylene / diene terpolymer. High dielectric composition for cable connections.   2. The high dielectric composition for cable connection according to claim 1, wherein the diene component of the ethylene / propylene / diene terpolymer is ethylidene norbornene.   The high dielectric composition for cable connection parts according to claim 1 or 2, characterized by containing 30 to 50 parts by mass of tetrapotted zinc oxide with respect to 100 parts by mass of the ethylene / propylene / diene terpolymer. .   4. The high dielectric property for a cable connection part according to claim 1, wherein 40 to 60 parts by mass of carbon black is contained with respect to 100 parts by mass of the ethylene / propylene / diene terpolymer. 5. Composition.   The high dielectric composition for cable connection parts according to any one of claims 1 to 4, wherein the tetrapot-like zinc oxide has an average fiber length (needle-like portion) of 5 to 15 µm. The relative dielectric constant (JIS K 6249) is 5.0 or more, and the volume resistivity at 23 ° C. is 1.0 × 10 ^{8 to} 1.0 × 10 ¹⁵ Ω · cm. The high dielectric composition for a cable connection part according to any one of 5. The relative dielectric constant at 23 ° C. (JIS K 6249) is 5.0 or more, and the volume resistivity at 23 ° C. (JIS K 6271) is 1.0 × 10 ^{10 to} 1.0 × 10 ¹³ Ω · cm. The high dielectric composition for a cable connection part according to any one of claims 1 to 5.   A cable connection part comprising an electric field relaxation layer made of the high dielectric composition according to claim 1.

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