JP2888666B2 - Casting resin composition and insulating spacer using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting resin composition suitable as an insulating material or a structural material for electric equipment and components, and more particularly to a gas insulated switchgear, a pipe air transmission device, or The present invention relates to a casting resin composition most suitable for use as an insulating spacer used in other electric devices, and an insulating spacer using the same.

[0003]

2. Description of the Related Art In recent years, gas-insulated switchgears and conduit air transmissions have been widely used as switchgears and power transmission devices for high voltage circuits constituting substations. In these gas insulated switchgears and conduit air transmission devices, insulating spacers are used to insulate and support the high-voltage conductor in the grounded metal container.

As such insulating spacers, for example, Japanese Patent Publication No. 54-44106 and Japanese Patent Application Laid-Open No.
A technique as disclosed in Japanese Patent No. 55512 has been proposed.
That is, in the insulating spacers disclosed in these publications, a high-voltage conductor is supported by an insulating spacer body made of a synthetic resin such as an epoxy resin, and the insulating spacer is fixed to a grounded metal container on a flange portion of the insulating spacer. Metal flange portion is formed. Also,
SF ₆ gas sealed in a grounded metal container, if the electric field is non-uniform, its insulation performance tends to decrease,
As a countermeasure, a ground shield is integrally embedded around the high-voltage conductor, and the potential is secured by the metal flange portion.

FIG. 1 is a longitudinal sectional view showing an example of a cone-shaped insulating spacer having the above-mentioned general configuration. As shown in FIG. 1, the high voltage conductors 1a and 1b
It is insulated and supported by a cone-shaped insulating spacer 4 in a grounded metal container 3 in which an insulating gas 2 such as SF ₆ gas is sealed. A current-carrying member 4a for joining the adjacent high-voltage conductors 1a and 1b is integrally cast on the insulating spacer 4. On the other hand, the grounding metal container 3 is provided with a connecting flange 5 for connecting adjacent grounding metal containers 3 to each other. On the other hand, a metal flange 6 is integrally cast at the outer edge of the insulating spacer 4, and the metal flange 6 is sandwiched by the connecting flange 5 formed on the grounded metal container 3, and the mounting bolt 7 As a result, the insulating spacer 4 is fixed to the grounded metal container 3. Further, a conductive ring 8 corresponding to the above-described ground shield is integrally cast on the insulating spacer 4, and the conductive ring 8 is always grounded, so that the grounded metal container 3 and the insulating spacer 4 are formed. The electric field at the coupling portion with the substrate is alleviated, and the insulation performance is improved. In the figure, reference numeral 9 denotes an O-ring interposed at a connection between the insulating spacer 4 and the grounded metal container 3, and the O-ring 9 provides an airtight seal.

The insulating spacer 4 having the above configuration
As an insulating casting material for the main body, an epoxy resin using an acid anhydride as a curing agent is generally used as a base material because of its chemical stability, mechanical strength, and the like. In particular, as an insulating spacer for a gas insulated switchgear using SF ₆ gas or the like as an insulating medium, (1) lower the material cost, (2) increase the elastic modulus and increase the rigidity of the product,
The epoxy resin is generally filled with alumina for the purpose of (3) improving the mechanical strength, (4) improving the formability by reducing the coefficient of linear expansion, and the like. .

[0007] On the other hand, the allowable value of the temperature rise of the conductor energized portion is increasing for the purpose of downsizing the equipment, and improvement in heat resistance (high temperature creep characteristic) of the resin for the insulating spacer is required. In order to improve heat resistance (high-temperature creep characteristics), a method of increasing the glass transition temperature of a resin is generally used. However, as the glass transition temperature increases, the brittleness of the resin increases, and furthermore, the embedded metal member and The thermal stress based on the difference in the coefficient of linear expansion increases, so that the crack resistance significantly decreases. On the other hand, as a method of improving the impact resistance of the resin itself, an impact resistance imparting component such as a modified low-molecular-weight polyolefin, polybutadiene, or silicone rubber described in International Publication No. W087 / 07900 is modified or mixed with an epoxy resin. Such methods exist. However, these conventional methods have not been sufficiently studied as structural materials for large-sized high-voltage components such as insulating spacers. There is room for development.

For this reason, in an insulating spacer used for a gas insulated switchgear using a gas such as SF ₆ gas or the like as an insulating medium or an air transmission device in a pipeline, an inorganic filler such as alumina is highly filled in the resin. A method for reducing the thermal stress by bringing the coefficient of linear expansion closer to the coefficient of linear expansion of the embedded metal member, maintaining the glass transition temperature of the resin, and improving the crack resistance while maintaining the heat resistance (high temperature creep characteristics) Is generally used.

[0009]

However, as described above, in an insulating spacer used in a gas insulated switchgear, a pipe air transmission device, or the like, an inorganic filler such as alumina is highly filled in a resin. In such a case, the following disadvantages have occurred. That is, since the dielectric constant of alumina is large, high filling of alumina increases the dielectric constant of the resin,
Disadvantageous in insulation design. In addition, high filling of alumina
In order to increase the modulus of elasticity of the resin, there is a drawback in that, in terms of mechanical properties, distortion at the time of breaking is small, and the breaking value at the product stage is reduced. Furthermore, high filling of alumina increases the viscosity of the resin at the time of casting, so that the pot life is shortened and the workability is reduced. In addition, since the conventional resin does not have a large adhesive force with the embedded metal member, it is generally necessary to perform a primer treatment on the metal member to secure a sufficient adhesive force. This also reduced workability.

As described above, in the conventional insulating spacers, high levels of heat resistance (high-temperature creep characteristics) and crack resistance have been achieved by filling alumina at a high level into the resin. However, such conventional techniques have problems such as an increase in the dielectric constant, a decrease in mechanical strength at the product stage, and a decrease in workability.

The various problems described above are not limited to insulating spacers used in gas-insulated switchgears and conduit air transmission devices, but also various large-sized devices using the same resin composition. It has also been present in insulating and structural materials for other electrical devices and components, such as castings and semiconductor encapsulation materials.

The present invention has been proposed to solve such problems of the prior art, and a first object of the present invention is to provide an insulating device used in a gas insulated switchgear, a pipe air transmission device, or the like. By improving the casting resin composition, the spacer achieves both high heat resistance (high temperature creep properties) and high crack resistance, and has a low dielectric constant. An object of the present invention is to provide an excellent insulating spacer having excellent strength and good workability.

A second object of the present invention is not only an insulating spacer, but also suitable as an insulating material or a structural material for other electric devices or components such as various large castings and semiconductor sealing materials. An object of the present invention is to provide such an excellent resin composition for casting.

[Configuration of the Invention]

[0015]

The resin composition for casting according to the present invention comprises: (A) at least two epoxy resins per molecule;
99 to 60 parts by weight of an epoxy compound having a xy group,
(B) unsaturated carboxylic acids and acid anhydrides;
At least one type of unsaturation selected from the group consisting of stells
Grafting carboxylic acid derivatives to low molecular weight polyolefins
Modified low molecular weight polyolefins 1-4 obtained by copolymerization
0 parts by weight, and the epoxy resin obtained by condensation polymerization.
A composition comprising a curing agent for a oxy resin,
Is characterized in that a fibrous filler is compounded alone or in combination .

The insulating spacer according to the present invention is used for a gas insulated switchgear, a pipe air transmission device, or other electric equipment, and insulates and supports a high-voltage conductor in a metal container or interposes another member. In the insulating spacer for performing the insulation described above, the resin composition for casting is used.

As the casting resin composition of the present invention, the following various components can be specifically used.

First, as the epoxy compound (A) used in the present invention, any epoxy compound having at least two epoxy groups in one molecule can be appropriately used, and the type thereof is limited. However, examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, hydrogenated bisphenol A type epoxy resin, and heterocyclic epoxy resin such as triglycidyl isocyanate and hydantoin epoxy. These compounds are used alone or as a mixture of two or more.

Next, the modified low molecular weight polyolefin (B)
As low molecular weight polyolefins used as raw materials for
Α- having 30 to 75 mol% of an ethylene component and 3 to 20 carbon atoms
It is desirable to use an ethylene random copolymer (ethylene / propylene random copolymer) having an olefin component of 25 to 70 mol% and a number average molecular weight of 400 to 2000. In particular, the ratio of ethylene / propylene is desirably about 50/50 in consideration of the balance between the heat resistance and the mechanical properties of the insulating spacer (or other cured product).

The modified low molecular weight polyolefin (B)
As an unsaturated carboxylic acid having 3 to 10 carbon atoms, an acid anhydride thereof, and at least one unsaturated carboxylic acid derivative component selected from the group consisting of esters thereof, based on 100 parts by weight of the low molecular weight polyolefin. It is desirable to use a material obtained by graft copolymerization of parts by weight. In this case, as the unsaturated carboxylic acid, maleic anhydride, acrylic acid and the like are desirable.

The epoxy compound (A) and the modified low molecular weight polyolefin (B) are physically mixed before reacting with the curing agent for epoxy resin (C), or the modified low molecular weight polyolefin is The acid anhydride ring and the carboxyl group, which are the graft polymerization components in (B), are used by reacting in advance with the epoxy group of the epoxy compound (A). In this case, the modified low molecular weight polyolefin (B)
If the amount is less than 1 part by weight, the effect of improving the properties is not sufficient, and if it is more than 40 parts by weight, the viscosity rise is large, which is not preferable in terms of workability. For these reasons, in the present invention, the blending amount of the modified low molecular weight polyolefin (B) is 1 to 40 parts by weight as described above.

The epoxy resin curing agent (C) used in the present invention generally includes aliphatic or aromatic acid anhydrides, carboxylic acids, amines and phenols used as epoxy resin compounds. Can be used alone or in the form of a mixture of two or more. In particular, phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, nadic anhydride, nadic anhydride, etc. Acid anhydrides are desirable. Among them, phthalic anhydride and methyl nadic anhydride are advantageous from the viewpoint of workability because they have a long pot life and fast curing, and their cured products have other curing properties. Better than when using the agent. The compounding amount of these curing agents for epoxy resin is preferably in the range of 0.7 to 0.9 equivalent relative to 1 equivalent of epoxy, and if less than this range, the insulating spacer (or other curing agent) may be used. ) Significantly deteriorates in heat resistance and environmental resistance such as moisture resistance. On the other hand, if the compounding amount is larger than this range, the chemical heat resistance and the electrical properties of the insulating spacer (or other cured product) are reduced.

On the other hand, in the casting resin composition of the present invention, any kind of filler can be blended as long as the workability is not hindered. For example, as a particulate filler, silica, alumina, talc, calcium carbonate, aluminum hydroxide, kaolin, clay, dolomite, mica powder, silicon carbide, glass powder, carbon, graphite, barium sulfate, titanium dioxide, boron nitride, Silicon nitride or the like can be used. Also, as a fibrous filler,
Wollastonite, potassium titanate whisker, glass fiber, alumina fiber, silicon carbide fiber, boron fiber, carbon fiber, aramid fiber, phenol fiber,
Metal whiskers and the like can be used. These fillers are used alone or as a mixture of two or more. Among them, alumina is the epoxy resin of the present invention, that is,
It has excellent adhesion to an epoxy resin modified by a modified low-molecular-weight polyolefin (B). In particular, by using alumina having an average particle diameter of 1.0 to 20 μm as a filler, SF ₆ decomposition gas resistance, An insulating spacer (or other cured product) having excellent thermal conductivity and mechanical strength can be obtained. The total amount of the filler is 3 to the total composition.
It is desirable that the content is 5% by volume or more and 55% by volume or less, if necessary. This is due to the fact that the phase loading of the filler is 35% by volume.
If the total amount of the filler is less than 55% by volume, the viscosity rises remarkably, and the casting operation becomes difficult. For that reason.

Incidentally, in the casting resin composition of the present invention, various additives can be blended as required. For example, additives such as a flame retardant, an antioxidant, a pigment, and a dye can be blended.

[0025]

By using the casting resin composition of the present invention having the above composition, an excellent insulating spacer can be easily produced by a usual method for producing an insulating spacer. That is, the epoxy compound (A) and the modified low-molecular-weight polyolefin (B) are sufficiently vacuum-mixed with the filler by a general method using a universal mixer, and then mixed with the epoxy resin curing agent (C). Then, it can be easily manufactured by the same manufacturing method as in the case of using a normal epoxy resin for insulating spacer casting, such as injection into a mold.

Further, the resin composition for casting of the present invention has the above composition, so that it can be heat-resistant while maintaining a low filling rate of an inorganic filler having a large dielectric constant and an elastic modulus such as alumina. (High temperature creep properties) and crack resistance at a high level. Therefore, the heat resistance (high-temperature creep characteristics) and the crack resistance can both be achieved at a high level, the dielectric constant can be reduced, and the mechanical strength at the product stage can be improved. In this case, since the pot life can be lengthened, there is an advantage that workability can be improved.

Further, when an insulating spacer is formed by using the casting resin composition of the present invention, the insulation reliability can be improved because the adhesive strength to the embedded metal member is large. In this case, the priming of the metal member, which is generally performed to secure the adhesive force between the casting resin composition and the embedded metal member, can be omitted, thereby contributing to further improvement in workability. it can.

The resin composition for casting of the present invention is suitable not only as an insulating spacer, but also as an insulating material or a structural material for other electric devices and components such as various large castings and semiconductor sealing materials. In the same manner, excellent characteristics can be exhibited.

[0029]

EXAMPLES Examples of insulating spacers using the resin composition for casting of the present invention and comparative examples according to the prior art are shown below, and comparative evaluations of the insulating spacers of these examples and comparative examples are shown below. The operation and effect of the present invention will be described in more detail. The insulating spacers prototyped in all Examples and Comparative Examples have the same configuration in which a conductive member 4a made of aluminum is arranged at the center in a cone shape as shown in FIG. An insulating spacer 4 (model spacer) having a maximum thickness of the resin portion of 90 mm was used.

Example 1 As a modified low molecular weight polyolefin (B), a maleic anhydride-grafted ethylene propylene random copolymer (containing 10% by weight of maleic anhydride, ethylene / propylene composition ratio = 50/50, number average molecular weight 900) was used. Used, as an epoxy compound (A),
Bisphenol A, bisphenol A type epoxy resin,
Using O-cresol novolak type epoxy resin,
A modified epoxy resin having an epoxy equivalent of 270 obtained by a condensation reaction of the modified low molecular weight polyolefin (B) and the epoxy compound (A) was obtained. Next, 100 parts by weight of the modified epoxy resin having an epoxy equivalent of 270, 45 parts by weight of phthalic anhydride as a curing agent (C) for an epoxy resin, and particulate alumina (average particle size of 12 μm) as a filler.
280 parts by weight are blended and used in a universal mixer at 110 to 120 parts.
The mixture was vacuum-mixed at ℃ to obtain a resin composition. Further, this resin composition was cast in a mold preheated to 120 ° C., and cured under the conditions of primary curing of 120 ° C. × 15 hours and secondary curing of 150 ° C. × 15 hours to produce a model spacer. In this embodiment, the primer treatment was not performed on the conductive member made of aluminum disposed at the center of the model spacer.

Example 2 As a modified low molecular weight polyolefin (B), a maleic anhydride-grafted ethylene propylene random copolymer (containing maleic anhydride at 10% by weight, ethylene / propylene composition ratio = 50/50, number average molecular weight 900) was used. Used, as an epoxy compound (A),
Using bisphenol A and bisphenol A type epoxy resin, these modified low molecular weight polyolefins (B)
And a modified epoxy resin having an epoxy equivalent of 390 prepared by a condensation reaction with the epoxy compound (A). Next, the modified epoxy resin 100 having an epoxy equivalent of 390 was used.
30 parts by weight of phthalic anhydride as a curing agent (C) for an epoxy resin and 250 parts by weight of particulate alumina (average particle size: 12 μm) as a filler were mixed with 1 part by weight, and mixed with a universal mixer.
The resin composition was obtained by vacuum mixing at 10 to 120 ° C. Further, the resin composition was cast in a mold preheated to 120 ° C., and primary curing was performed at 120 ° C. × 10 hours, and secondary curing was performed at 130 ° C.
The composition was cured under the conditions of × 15 hours to produce a model spacer. In this embodiment, the primer treatment was not performed on the conductive member made of aluminum disposed at the center of the model spacer.

(Example 3) The resin composition and curing conditions were exactly the same as in Example 2 to prepare a model spacer.
However, in the present embodiment, a primer treatment was performed on the conductive member made of aluminum disposed at the center of the model spacer.

On the other hand, a casting resin composition which is generally used as a large casting insulating resin is adopted as a comparative example according to the prior art with respect to the above-described embodiment according to the present invention. A model spacer was manufactured under the following conditions.

Comparative Example 1 As an epoxy resin, bisphenol A type epoxy resin (epoxy equivalent: 390) 85
Parts by weight, and 15 parts by weight of alicyclic epoxy resin,
35 parts by weight of phthalic anhydride as a curing agent and 320 parts by weight of particulate alumina (average particle size: 12 μm) as a filler were mixed in a universal mixer at 110 to 120 ° C. under vacuum to obtain a resin composition. Then, the resin composition is heated at 120 ° C.
Was cast in a preheated mold, and cured under the conditions of primary curing of 120 ° C. × 15 hours and secondary curing of 150 ° C. × 15 hours to produce a model spacer. In this comparative example,
A primer treatment was performed on the aluminum conductive member disposed at the center of the model spacer in the same manner as in Example 3.

Comparative Example 2 As the epoxy resin, bisphenol A type epoxy resin (epoxy equivalent: 390) 10
0 parts by weight, 30 parts by weight of phthalic anhydride as a curing agent, and particulate alumina as a filler (average particle size: 12 μm)
300 parts by weight are blended and used in a universal mixer at 110 to 120
The mixture was vacuum-mixed at ℃ to obtain a resin composition. Then, this resin composition was cast in a mold preheated to 120 ° C., and cured under the conditions of primary curing of 120 ° C. × 15 hours and secondary curing of 130 ° C. × 15 hours to produce a model spacer. In this comparative example, a primer treatment was performed on the aluminum conductive member disposed at the center of the model spacer in the same manner as in Example 3.

(Comparative Example 3) The resin composition and curing conditions were exactly the same as those of Comparative Example 2, and a model spacer was produced.
However, in this comparative example, no primer treatment was performed on the conductive member made of aluminum disposed at the center of the model spacer.

Table 1 shows the evaluation results of the model spacers manufactured in Examples 1 to 3 and Comparative Examples 1 to 3. Of the various characteristics shown in Table 1, the fracture stress is obtained by gradually applying an internal pressure to a model spacer incorporated in a predetermined test apparatus.
It was calculated from the maximum value of the surface strain associated with the load pressure measured by the strain gauge. The starting point of the destruction was the interface between the current-carrying member and the resin in each of the model spacers. On the other hand, the glass transition temperature Tg was obtained by measuring a sample cut out from the model spacer with a differential scanning calorimeter (DSC) and determining a change in specific heat. As the thermal shock resistance, a crack resistance index of each resin used according to a M20 flat washer method was described.

[0038]

[Table 1]

As is clear from Table 1 above, in the examples of the present invention, both the glass transition temperature and the thermal shock resistance are superior to those of the comparative example according to the prior art. High temperature creep characteristics) and high level of crack resistance. Moreover, it is clear that the examples of the present invention have a lower relative dielectric constant and are superior in the breaking stress at the product stage, as compared with the comparative example according to the prior art.

Further, in Comparative Examples 2 and 3 according to the prior art, there is a difference in the fracture stress depending on the presence or absence of the primer treatment, whereas in Examples 2 and 3 according to the present invention, the difference in the fracture stress occurs. Irrespective of the presence or absence of, a stable high fracture stress is obtained. This demonstrates that when an insulating spacer is manufactured using the casting resin composition of the present invention, no primer treatment is required, and the workability can be improved accordingly.

The resin composition for casting according to the present invention comprises:
The present invention is not limited to the above-described embodiment, and various kinds of materials can be selectively used as described in the section of the means for solving the problem. The function and effect can be obtained. Further, the application of the resin composition for casting according to the present invention is not limited to the insulating spacer, and as described above, the insulating resin composition for various electric devices and components such as various large castings and semiconductor sealing materials. It is also suitable as a material or a structural material.

[0042]

As described above, the casting resin composition of the present invention is a novel resin composition obtained by mixing a certain modified low molecular weight polyolefin with an epoxy resin. When insulating spacers are manufactured using a resin composition for molding, the heat resistance (high temperature creep properties) and crack resistance of the insulating spacers using a conventional general epoxy resin composition for casting are improved. It is possible to provide an excellent insulating spacer having a high level of compatibility, a low dielectric constant, excellent mechanical strength at the product stage, and good workability.

Further, the resin composition for casting of the present invention is suitable not only as an insulating spacer but also as an insulating material or a structural material for various electric devices and parts such as various large castings and semiconductor sealing materials. It is.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a cone-shaped insulating spacer having a general configuration as an application example of an insulating spacer according to the present invention.

[Explanation of symbols]

 1a, 1b High voltage conductor 2 Insulating gas 3 Ground metal container 4 Insulating spacer 4a Current carrying member 5 Connecting flange 6 Metal flange 7 Mounting bolt 8 Conductive ring 9 O-ring

Continuing from the front page (72) Inventor Ichikawa Ichiro 21-4 Kanseicho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Chemical Co., Inc. (56) References JP-A-64-33122 (JP, A) JP-A-56-139525 (JP, A) JP-A-62-43462 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) C08G 59/14 C08L 63/00-63/10 H02G 5/06

Claims (2)

(57) [Claims] (1) 99 to 60 parts by weight of an epoxy compound having two or more epoxy groups in at least one molecule, and (B) an unsaturated carboxylic acid, an acid anhydride and an ester thereof. Modified low-molecular-weight polyolefins obtained by graft copolymerizing at least one unsaturated carboxylic acid derivative with low-molecular-weight polyolefins
0 parts by weight, and an epoxy resin obtained by polycondensation with
A resin composition for casting, characterized in that a particulate or fibrous filler is compounded alone or in combination with a composition obtained by adding a curing agent for molding. 2. A gas insulated switchgear, a pipeline air transmission device,
Or an insulating spacer used for other electrical equipment for insulatingly supporting a high-voltage conductor in a metal container or performing insulation between other members, using the casting resin composition according to claim 1. An insulating spacer, comprising: