JP2000341844A - Rubber molding and its molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable use as an intermediate junction or end junction for power cables by forming a large-sized rubber molding, using an ethylene propylene rubber compound comprising a dialkyl peroxide cross linking agent whose half life becomes a specific time at temperatures in a specific range, and surface-treated burned clay. SOLUTION: For forming a rubber molding, an ethylene propylene insulating rubber compound comprising a dialkyl peroxide cross linking agent whose half-life becomes ten hours at temperatures of 120 to 130 deg.C, and a surface-treated burned clay are used as insulating materials. Molding of insulating rubber material is performed by pressurization and vulcanization after it is caused to have a required shape by winding insulating rubber having a tapelike shape, and so on. Besides, insulating rubber material is molded after a semiconductive rubber material layer molded in advance is set in a metal mold, when the insulating rubber material is molded. Consequently, the molding becomes sufficiently usable as an intermediate function or end junction for higher-voltage power cables.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber molded product used for an intermediate connection portion and a termination connection portion of a power cable.

[0002]

2. Description of the Related Art A rubber molded product such as a rubber stress relief cone or a rubber pre-mold joint used for an intermediate connection portion or a terminal connection portion of a power cable is configured to sufficiently withstand a high working voltage of the power cable. There is a need. Therefore, a composition mainly composed of an ethylene-propylene polymer excellent in heat resistance, electric properties, and the like and containing a crosslinking agent is generally used.

[0003]

With the recent increase in power demand, the power cables have been further increased in voltage, and the power cables have been further increased in size. Along with this, accessories for power cables, for example, rubber molded products such as rubber stress relief cones and rubber pre-mold joints used for intermediate connection portions and terminal connection portions of power cables have to be enlarged. For example, 66k
The capacity of the rubber stress relief cone used for the intermediate connection part of the V class power cable is about 700 cc, whereas the 154 kV class requires about 2000 cc, which is about 7 times as large. . Such a large molded product takes a long time to mold. By the way, the 66kV class can be molded at 160 ° C in about 5 minutes,
154 kV class takes about 20 minutes at 160 ° C. Therefore, when such a large molded product is molded by using the conventional ethylene propylene rubber compound, a prematurely crosslinked product is formed inside the molded product, which becomes an electric defect portion, and a problem that a withstand voltage is lowered occurs. Cheap.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a large-sized rubber molded product having excellent withstand voltage. And molding the large rubber molded product using an ethylene propylene rubber compound containing a dialkyl peroxide-based crosslinking agent having a half-life of 10 hours and a temperature of 120 ° C. or more and 130 ° C. or less.

[0005]

Embodiments of the present invention will be described below. The rubber molded article of the present invention has a surface-treated calcined clay and a temperature at which the half-life is 10 hours is 120 ° C. or more and 1 hour.
An ethylene propylene insulating rubber compound containing a dialkyl peroxide-based crosslinking agent at 30 ° C. or lower is used as an insulating material.

[0006] Surface-treated calcined clay is preferable because of its superior electrical properties compared to other fillers such as calcium carbonate and talc. Further, it is an important feature of the present invention that the use of the surface-treated calcined clay makes it easy to prevent premature crosslinking. For the surface treatment of the calcined clay, fatty acids, silane coupling agents, titanium coupling agents, and the like can be used. Among them, vinyl silane coupling agents are preferable because they can improve the strength of rubber.

The crosslinking agent has a half-life of 10 hours at a temperature of 12
A dialkyl peroxide-based crosslinking agent having a temperature of 0 ° C to 130 ° C is used. If the temperature is lower than 120 ° C., even if a surface-treated calcined clay is used, premature crosslinking occurs during molding, and the withstand voltage decreases. If the temperature exceeds 130 ° C., it takes too much time for crosslinking, which is not practical. The peroxide-based crosslinking agent includes hydroperoxide and ketone peroxide, but dialkyl peroxide is preferred from the viewpoint of stability and economy. Among the dialkyl peroxides, 1, 3
Bis (tert-butylperoxyisopropyl) benzene (temperature of 121 ° C. with a half-life of 10 hours), 2,5-dimethyl-2,5 (tert-butylperoxy) hexyne-3
(Temperature of 127 ° C. with a half-life of 10 hours) is practically preferable in terms of cost and is preferable.

In addition to the surface-treated calcined clay and the crosslinking agent, processing aids, anti-aging agents, plasticizing oils, inorganic fillers, etc. are added to the ethylene propylene insulating rubber compound of the present invention in a timely manner. You may.

[0009] Insulating rubber material is formed by winding a tape-like insulating rubber into a required shape and then vulcanizing under pressure. However, voids are easily formed, and transfer molding or injection molding is used. However, it is preferable because it is easy to mold without forming a void which becomes a defect portion in the withstand voltage characteristics. When molding the insulating rubber material, it is better to set the previously formed semiconductive rubber material layer in a mold, then mold the insulating rubber material, mold the insulating rubber material first, and then semiconductive It is preferable because the adhesion between the two is improved as compared with molding rubber. In addition, it is very difficult to simultaneously mold both into a desired shape.

[0010]

EXAMPLE As an example, a rubber stress relief cone for 154 kV having a cross section shown in FIG. As an insulating rubber body, a fired clay (Translink 37 clay: Engelhard Miner) surface-treated with a vinylsilane coupling agent with respect to 100 parts by weight of ethylene propylene rubber
als Corp.) and 2,5-dimethyl-2,5 (third) as a dialkyl peroxide-based crosslinking agent.
An ethylene propylene insulating rubber compounded with 2 parts by weight of (butylperoxy) hexine-3 (temperature at which the half-life was 10 hours at 127 ° C.) was used.

As Comparative Example 1, a rubber stress relief cone having the same shape and the same size as that of the example was molded on trial. However, in Comparative Example 1, as an insulating rubber body, 100 parts by weight of a fired clay (Translink 37 clay: manufactured by Engelhard Minerals Corp.) whose surface was treated with a vinylsilane coupling agent was used for 100 parts by weight of ethylene propylene rubber. An ethylene propylene insulating rubber compounded with 2 parts by weight of dicumyl peroxide (temperature at which half-life is 10 hours: 117 ° C.) was added as a dialkyl peroxide-based crosslinking agent.

As a comparative example 2, a rubber stress relief cone having the same shape and the same size as the example was molded and manufactured. However, in Comparative Example 2, a calcined clay (Satinton SP33 clay: Engelh) without surface treatment was applied to 100 parts by weight of ethylene propylene rubber as an insulating rubber body.
ard Minerals Corp.) and 2,5-dimethyl- as a dialkyl peroxide-based crosslinking agent.
An ethylene propylene insulating rubber compounded with 2 parts by weight of 2,5 (tertiary butylperoxy) hexine-3 (temperature at which the half-life is 10 hours at 127 ° C.) was added.

Using the three types of rubber stress relief cones of Example, Comparative Example 1 and Comparative Example 2, each of the end terminations in gas shown in FIG. 2 was manufactured and subjected to an AC breakdown test. 1 used 300 kV, the rubber stress relief cone portion caused insulation breakdown at the starting point, and Comparative Example 2 used 350 kV, the rubber stress relief cone portion also caused insulation breakdown at the starting point. The one using the example did not break down even at 500 kV.

[0014]

As described above, since the rubber molded product of the present invention has a high withstand voltage, it can be sufficiently used as an intermediate connecting portion and a terminating connecting portion corresponding to recent high voltage of power cables. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a rubber stress relief cone of the present invention.

FIG. 2 is a cross-sectional view showing one example of a terminal connection part in 154 kV gas.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulated rubber body 2 Semi-conductive rubber body 11 Conductor lead-out rod 12 Epoxy sleeve 13 Rubber stress relief cone 14 Push pipe

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Koji Sadamoto 1-3-1 Shimaya, Konohana-ku, Osaka City F-term in Osaka Works, Sumitomo Electric Industries, Ltd. 5G375 AA02 BA21 BA26 BB46 CB03 CB05 CB12 CB36

Claims (7)

[Claims] 1. A calcined clay subjected to a surface treatment, and a half-life of 1
A rubber molded product characterized by using an ethylene propylene rubber compound containing a dialkyl peroxide-based crosslinking agent having a temperature of 0 hours of 120 ° C or more and 130 ° C or less. 2. The molded rubber article according to claim 1, wherein the surface-treated calcined clay is a surface-treated calcined clay with a vinylsilane coupling agent. 3. The molded rubber article according to claim 1, wherein the crosslinking agent is 1,3-bis (tert-butylperoxyisopropyl) benzene. 4. The rubber molded article according to claim 1, wherein the crosslinking agent is 2,5-dimethyl-2,5 (tert-butylperoxy) hexyne-3. 5. A calcined clay subjected to a surface treatment, and a half-life of 1
A transfer molding or injection molding method using an ethylene propylene rubber compound containing a dialkyl peroxide-based crosslinking agent having a temperature of 0 hours of 120 ° C. or more and 130 ° C. or less, and a transfer molding method or an injection molding method. 6. The method for molding a rubber molded product according to claim 5, wherein the insulating rubber material is molded after setting the previously molded semiconductive rubber material layer in a mold. 7. The rubber molded product according to claim 1, wherein the molded product is a rubber stress relief cone or a rubber pre-mold joint used for an intermediate connection portion and a terminal connection portion of a power cable of 110 kv or more.