JP5072256B2 - Insulating spacer, manufacturing method thereof, and gas insulating switchgear using the same - Google Patents

Description

  The present invention relates to an insulating spacer that insulates and supports a conductor in a metal container, a manufacturing method thereof, and a gas-insulated switchgear using the insulating spacer.

  In general, an insulating spacer is used in a gas-insulated switchgear or a pipeline air power transmission device to insulate and support a high-voltage conductor in a grounded metal container. This insulating spacer is made of a thermosetting resin such as an epoxy resin, and a ring-shaped shield metal made of metal or conductive resin is embedded therein. Here, a conventional example of an insulating spacer will be described below with reference to the drawings.

That is, as shown in FIG. 5, a grounded metal container 1 contains a high-voltage conductor 2 and an insulating gas 3 such as SF ₆ gas is enclosed. An insulating spacer 5 is attached in the metal container 1. The insulating spacer 5 insulates and supports the high voltage conductor 2 with respect to the metal container 1.

  A metal electrode 4 is integrally cast at the center of the insulating spacer 5, and the adjacent high voltage conductors 2, 2 are joined by this metal electrode 4. Further, the insulating spacer 5 is composed of an epoxy resin 9, and a metal ring-shaped shield body 6 is embedded in the epoxy resin 9. That is, the insulating spacer 5 is integrally provided with a metal member such as the metal electrode 4 or the shield body 6, but at the interface between the metal member and the epoxy resin 9 that is the material of the insulating spacer 5. In this case, thermal stress is generated by thermal expansion and contraction of the epoxy resin 9.

  For this reason, if the adhesiveness between the epoxy resin 9 which is the material of the insulating spacer 5 and the metal member such as the shield body 6 is lowered and partial peeling occurs, there is a possibility that electric discharge is generated therefrom. . When partial discharge occurs, it may lead to serious troubles such as dielectric breakdown. Since the gas-insulated switchgear is used for a long period of time when a high voltage is always energized, high reliability is required over a long period. Therefore, in order to ensure the reliability of the device, the soundness of the adhesive interface between the epoxy resin 9 which is the material of the insulating spacer 5 and the metal member such as the shield body 6 embedded in the insulating spacer 5 is maintained. Was indispensable.

  As a conventional example of an insulating spacer that improves the bonding strength between a resin that is a material of the insulating spacer 5 and a metal member embedded therein, a technique described in Patent Document 1 has been proposed. This is characterized in that the metal member is bonded to the resin by a sintering shrinkage that shrinks so that the metal member presses the resin (insulator).

In general, sandblasting or degreasing cleaning is known as a process for increasing the adhesive strength between the resin that is the material of the insulating spacer 5 and the metal member. Sandblasting is a process for removing a fragile oxide film on the surface of a metal member, and by increasing the surface area of the metal member, the adhesive strength with the resin is increased. On the other hand, degreasing and cleaning is a process for removing oil and fat adhering to the surface of the metal member, and by realizing direct contact between the metal surface and the resin, the adhesive strength between the two is enhanced.
JP 2002-75097 A

  In recent years, gas-insulated switchgear has been aimed at downsizing from the viewpoint of land acquisition difficulty and environmental harmony in the suburbs of cities. At the same time, high-voltage power transmission from a long distance is required, so the capacity is being increased. In order to achieve a reduction in size and increase in capacity of such a gas insulated switchgear, further improvement is required regarding the adhesive strength between the resin that is the material of the insulating spacer and the metal member embedded therein. Yes.

  In recent years, techniques for curing a resin in a short time, such as a pressure gelation method, have been applied when manufacturing an insulating spacer. The pressure gelation method is a production method in which a liquid resin such as an epoxy resin that has been fed is filled in a mold and solidified. In this pressure gelation method, in order to cure the resin in a short time, a curing treatment must be performed at a higher temperature than before. As a result, the cooling width for the insulating spacer from the curing temperature to the room temperature is increased. In other words, when the pressure gelation method is adopted as a method for manufacturing the insulating spacer, even when the cooling width is large, the interfacial separation between the resin that is the material of the insulating spacer and the metal member embedded therein may occur. Increasing the adhesive strength between the two is an even more important technical factor.

  As described above, the bonding strength between the metal member and the resin in the insulating spacer is required to be higher than before. For this reason, simply performing sandblasting and degreasing cleaning may cause a reduction in the adhesion strength between the metal member and the resin due to oxidation of the surface of the metal member and adhesion of oil, moisture or foreign matter to the surface, The improvement was awaited.

  The present invention has been proposed in view of such circumstances, and its purpose is to further increase the adhesive strength between the resin that is the material of the insulating spacer and the metal member embedded therein, and to improve the state. By stabilizing, it is always at a high level without causing separation at the adhesive interface between the resin and metal, even when exposed to high temperatures during the manufacture of insulating spacers or when the product is heated for a long period of time. It is intended to contribute to the realization of a reliable and small-sized and large-capacity gas-insulated switchgear.

In order to achieve the above object, the present invention provides a resin insulating spacer that supports and supports a conductor contained in a grounded metal container from the metal container, and sandblasts the surface of the aluminum member, The surface subjected to sandblasting is subjected to a chemical surface treatment using dichromic sulfuric acid , washed with water and dried, and after applying a primer to the adhesive interface between the aluminum member and the resin, the aluminum member is An insulating spacer embedded in the resin , wherein the primer includes a bisphenol type epoxy resin and an orthocresol novolac type epoxy resin, and the total of the orthocresol novolak type epoxy resin and the bisphenol type epoxy resin is 100 weights. Part, the bisphenol type epoxy resin is 50-90 The amount unit, a mixture in which the ortho-cresol novolac type epoxy resin is composed of 50-10 parts by weight, characterized in that is obtained by diluting with acetone and alcohol.

  In the present invention, the surface of the metal member is subjected to a chemical surface treatment, a primer is applied, and the metal member is embedded in the resin that is the material of the insulating spacer. Since it can be maintained for a long time, the adhesive strength between the resin and the metal member can be maintained at a high level for a long time.

  According to the present invention, the resin and the metal member embedded therein can be bonded with high strength, and the state can be maintained for a long time. Gas insulating switchgear that can be provided with an insulating spacer that always has a high level of adhesive strength, and that can be used to provide a small and large capacity. Can contribute to the improvement of reliability.

  Hereinafter, typical embodiments according to the present invention will be specifically described with reference to the drawings. FIG. 1 is an enlarged view of a main part of an insulating spacer to which this embodiment is applied, FIG. 2 is a configuration diagram of a test piece to which this embodiment is applied, and FIGS. 3 and 4 are graphs of test results by the test piece shown in FIG. It is.

[Constitution]
As shown in FIG. 1, the insulating spacer 10 according to the present embodiment is for insulatingly supporting the high voltage conductor 2 accommodated in the metal container 1 from the metal container 1, similarly to the insulating spacer 5 shown in FIG. 5. It is a member and is used for a gas insulated switchgear. The insulating spacer 10 is composed of an epoxy resin 11 for filling alumina or pressure gel, and is manufactured by vacuum casting. As in the insulating spacer 5 of FIG. 5, a metal ring-shaped shield body 12 is embedded in the epoxy resin 11, and although not shown, a metal electrode is integrally provided at the center. Yes.

  The structural features of this embodiment are as follows. That is, the surface of the shield body 12 is first subjected to sand blasting to provide a sand blast portion 13, and a chemical surface treatment portion 14 is formed there. Further, a primer 15 is applied to the adhesive interface between the epoxy resin 11 and the shield body 12, and the shield body 12 is embedded in the epoxy resin 11 on the primer 15.

  The sandblast portion 13 is provided by roughening the surface of the shield body 12 to 30 to 60 μm. Moreover, the shield body 12 is comprised from aluminum, and the surface treatment part 14 is formed by using a dichromic sulfuric acid. In addition, dichromic acid sulfuric acid consists of sulfuric acid 100-500 g / l aqueous solution and sodium dichromate 50-200 weight part / l aqueous solution.

  The primer 15 is obtained by diluting a mixture of 100 parts by weight of a bisphenol type epoxy resin, 30 to 75 parts by weight of polyvinyl butyral and 3 to 15 parts by weight of a phenol resin with acetone and alcohol. Among these, as the bisphenol type epoxy resin, for example, a resin obtained by directly reacting 2,2′-bis (4-hydroxyphenyl) propane and epichlorohydrin, or 2,2′-bis (4-hydroxyphenyl) methane. And a resin obtained by directly reacting chlorohydrin with epichlorohydrin. These epoxy resins are commercially available from Japan Epoxy Corporation under the trade names Epicoat 825, Epicoat 827, Epicoat 828, Epicoat 807, and the like.

  Polyvinyl butyral is a resin synthesized by reacting butyraldehyde under an acid catalyst of polyvinyl butyl alcohol. It is more desirable to use polyvinyl butyral in the range of 30 to 50 parts by weight. Furthermore, the phenol resin is a cocondensate obtained from phenol, cresol and formalin.

[Comparison test]
The following comparative test was performed in order to specifically show the effects of the present embodiment. That is, as shown in FIG. 2, as butt adhesion test pieces of aluminum round bar (A6061BET6) 7, Examples 1 and 2 to which this embodiment is applied and Comparative Examples 1 and 2 to which this embodiment is not applied are made. The tensile fracture strength was compared. In FIG. 2, reference numeral 8 denotes a casting resin.

Example 1
The adhesive interface of the aluminum round bar 7 is sandblasted to a surface roughness of 45 μm, subjected to chemical surface treatment with 280 g / l aqueous solution of sulfuric acid and 110 g / l aqueous solution of sodium dichromate, washed with water and dried. Subsequently, a primer is applied and dried at 120 ° C. for 2 hours to obtain a pretreated product. 1 hour, 6 hours, 1 day, 3 days, 7 days, and 14 days after treatment, vacuum casting is performed with alumina-filled epoxy resin, and primary curing is 115 ° C x 115H, secondary curing is 130 ° C x 10H. To obtain an adhesion test piece having the shape of FIG.

(Comparative Example 1)
After sandblasting the adhesion interface of the aluminum round bar 7 to a surface roughness of 45 μm and degreasing and cleaning, as in Example 1, 1 hour, 6 hours, 1 day, 3 days, 7 days, and 14 days later Vacuum casting was performed with the same alumina-filled epoxy resin as in Example 1, and primary curing was performed at 115 ° C. × 115 H, and secondary curing was performed at 150 ° C. × 15 H to obtain an adhesion test piece having the shape shown in FIG.

(Results of Comparative Test of Example 1 and Comparative Example 1)
In Example 1 and Comparative Example 1, the initial adhesive strength and the adhesive strength after adding 10 cycles of −40 ° C. ← → 115 ° C. heat shock in liquid are shown in the graph of FIG. As is apparent from this graph, Example 1 has an improved initial adhesive strength as compared with Comparative Example 1, and almost no decrease in the adhesive strength is observed even after 2 weeks from the treatment. Moreover, even when the heat cycle is performed, the adhesive strength is not lowered.

  On the other hand, in Comparative Example 1, the initial adhesive strength is as low as about 70% of Example 1, and the adhesive strength decreases with the passage of the standing time. After 24 hours, the initial adhesive strength decreases to 75% of the initial value. become. In some cases, the film was completely peeled off before the test under the influence of heat cycle.

(Example 2)
A pre-processed product is prepared in the same manner as in Example 1 above, vacuum-cast with an epoxy resin for pressure gel, primary curing 135 ° C. × 0.5 H, secondary curing 150 ° C. × 15 H, and the shape shown in FIG. The adhesion test piece was obtained.

(Comparative Example 2)
The same treatment as in Comparative Example 1 above was performed, and vacuum casting was performed with the same epoxy resin for pressure gel as in Example 2, followed by primary curing 135 ° C. × 0.5 H and secondary curing 150 ° C. × 15 H. An adhesion test piece having the shape shown in FIG. 2 was obtained.

(Results of Comparative Test of Example 2 and Comparative Example 2)
In Example 2 and Comparative Example 2, the initial adhesive strength and the adhesive strength after adding 10 cycles of −40 ° C. ← → 115 ° C. heat shock in liquid are shown in the graph of FIG. As is apparent from this graph, even in the case of the epoxy resin for pressure gel, the result is the same as the comparative test shown in FIG. 3, and when this embodiment is used, the adhesive strength between the metal member and the resin is high. It was found to be stable at the level and tolerate heat cycles after the product.

[Function and effect]
As described above, in the present embodiment, the chemical surface treatment portion 14 is formed on the surface of the shield body 12, the primer 15 is applied, and then embedded in the epoxy resin 11, thereby activating the surface of the shield body 12. However, the adhesive strength with the epoxy resin 11 is maintained at a high level. In addition, by providing the sandblast portion 13, the adhesion surface area is increased, and the maximum adhesion improvement effect is obtained.

  Moreover, since aluminum is used as the material of the shield body 12, the difference in thermal expansion coefficient from the epoxy resin 11 is reduced, and the thermal stress at the adhesive interface due to temperature fluctuation can be reduced. Furthermore, surface treatment using sulfuric acid 100-500 g / l aqueous solution and sodium dichromate 50-200 parts by weight / l aqueous solution is optimal for aluminum, and high adhesive strength can be obtained. Become.

  Moreover, the polyvinyl butyral added to the primer 15 can impart flexibility to the primer 15 and can relieve stress generated at the interface between the shield body 12 and the epoxy resin 11 which are metal members. Polyvinyl butyral is in the range of 30 to 75 parts by weight, and this range is optimal because it has the effect of maintaining the heat resistance of the primer 15 while obtaining a sufficient stress relaxation effect.

  In this embodiment, since the adhesive strength between the epoxy resin 11 and the shield body 12 is extremely high, a pressure gelation method involving a curing process at a high temperature can be adopted without any problem, and the epoxy resin 11 and the shield body are cooled during the cooling process. Insulating spacer 10 can be manufactured in a short time without causing interfacial delamination with 12.

  According to the insulating spacer 10 as described above, the interface between the epoxy resin 11 and the shield body 12 is not affected even when exposed to high temperatures during manufacture, or even if the temperature is increased for a long time after being manufactured. No peeling occurs and high adhesive strength can be realized over a long period of time. Further, by using such an insulating spacer having high adhesive strength, it is possible to improve the reliability of the gas insulated switchgear having a small size and large capacity.

[Other Embodiments]
In addition, this invention is not limited to said embodiment, The following other embodiment is also included. For example, the type of resin used as the material of the insulating spacer, the type of metal member embedded in the bottom, and the like can be selected as appropriate. Moreover, you may use a silane coupling agent as a primer. Furthermore, instead of 100 parts by weight of the bisphenol-type epoxy resin in the primer 15, a mixture is prepared as 50-90 parts by weight of a bisphenol-type epoxy resin and 50-10 parts by weight of an orthocresol novolac-type epoxy resin, and diluted with acetone and alcohol You may get it.

  The ortho-cresol novolac resin is, for example, a resin obtained by reacting novolak resin obtained by reacting ortho-cresol and formaldehyde under acidic conditions and epichlorohydrin in the presence of alkali. Ortho-cresol novolac type epoxy resin is added to increase the glass transition temperature of the primer and improve the heat resistance of the primer, but if added too much, the flexibility of the primer is reduced and occurs at the interface between the metal part and the epoxy resin. The stress relaxation effect is reduced. For this reason, it is preferable that the orthocresol novolac resin is 10 to 50 parts by weight out of the total 100 parts by weight of the bisphenol type epoxy resin and the orthocresol novolac resin.

The principal part enlarged view of typical embodiment which concerns on this invention. The block diagram of the test piece to which this embodiment is applied. The graph of the test result by the test piece shown in FIG. The graph of the test result by the test piece shown in FIG. The block diagram of the conventional insulation spacer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal container 2 ... High voltage conductor 3 ... Insulating gas 4 ... Metal electrode 5, 10 ... Insulating spacer 6, 12 ... Shield body 7 ... Aluminum round bar 8 ... Cast resin 9, 11 ... Epoxy resin 13 ... Sand blast part 14 ... Surface treatment part 15 ... Primer

Claims (3)

In a resin-made insulating spacer that supports and insulates the conductor contained in the grounded metal container from the metal container,
Sandblasting the surface of the aluminum member,
This sandblasted surface is subjected to a chemical surface treatment using dichromated sulfuric acid , washed with water and dried,
After applying a primer to the adhesive interface between the aluminum member and the resin,
An insulating spacer in which the aluminum member is embedded in the resin ,
The primer includes a bisphenol type epoxy resin and an orthocresol novolak type epoxy resin, and the total amount of the orthocresol novolak type epoxy resin and the bisphenol type epoxy resin is 100 parts by weight, and the bisphenol type epoxy resin is 50 to 90% by weight. An insulating spacer , wherein the orthocresol novolac type epoxy resin is a mixture of 50 to 10 parts by weight diluted with acetone and alcohol . In a gas-insulated switchgear that accommodates a conductor in a grounded metal container and insulates and supports the conductor from the metal container with an insulating spacer,
Sandblasting the surface of the aluminum member,
This sandblasted surface is subjected to a chemical surface treatment using dichromated sulfuric acid , washed with water and dried,
The adhesive interface between the aluminum member and the resin of the insulating spacer contains a bisphenol type epoxy resin and an orthocresol novolak type epoxy resin, and the total of the orthocresol novolak type epoxy resin and the bisphenol type epoxy resin is 100 parts by weight, After applying a primer composed of 50 to 90 parts by weight of the bisphenol type epoxy resin and 50 to 10 parts by weight of the orthocresol novolac type epoxy resin diluted with acetone and alcohol ,
A gas insulated switchgear characterized in that the metal member is embedded in the insulating spacer. In a method of manufacturing an insulating spacer in which a conductor housed in a grounded metal container is insulated from and supported by the metal container, and a metal member made of aluminum is embedded in the resin,
Applying sandblast to the surface of the metal member ;
Applying a chemical surface treatment using dichromic sulfuric acid to the sandblasted surface , washing with water and drying;
A bisphenol-type epoxy resin and an ortho-cresol novolac-type epoxy resin are included in the adhesive interface between the metal member and the resin, and the total of the ortho-cresol novolac-type epoxy resin and the bisphenol-type epoxy resin is 100 parts by weight. An insulating spacer comprising: a primer application step of applying a primer diluted with acetone and alcohol to a mixture of 50 to 90 parts by weight of an epoxy resin and 50 to 10 parts by weight of the ortho-cresol novolak type epoxy resin. Manufacturing method.

Images