Mold resin for power receiving and distributing device, power receiving and distributing device, and method for manufacturing power receiving and distributing device

Abstract

To improve the storage stability of mold resins for power receiving and distributing devices under high-temperature conditions and enhance their molding reliability.SOLUTION: A starting material liquid for a mold resin includes: a base agent liquid that is mainly composed of an epoxy resin and silica; a curing agent liquid that is mainly composed of an acid anhydride and silica; and a reactive diluent liquid that is mainly composed of a radical monomer and a copolymerization agent.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a molding resin for an electric power receiving and distributing device, an electric power receiving and distributing device, and a method for manufacturing the electric power receiving and distributing device. [Background technology]

[0002] Thermosetting resins are preferred for molding resins used in power distribution equipment from the viewpoint of heat resistance and durability. Thermosetting resins are molded into the desired shape by increasing the temperature, so they are mostly liquid or gel-like at room temperature. However, when the environmental temperature increases, the viscosity of the resin decreases, especially in the case of liquid resins, and the solid components (fillers) contained within may settle.

[0003] The settled filler was originally contained in the resin liquid, and should have been included in the cured resin when the resin liquid was cured.

[0004] Therefore, the physical properties of the cured product may differ from the original design values, which may cause problems in product performance. In addition, the settled filler is often silica or alumina, and once settled, it solidifies at the bottom of the container and becomes integrated with the container, which requires the container to be disposed of as industrial waste, increasing costs.

[0005] Therefore, measures are taken to suppress filler settling during storage by adjusting the viscosity of the resin liquid. Related techniques include, for example, Patent Documents 1, 2, and 3. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-128621 A [Patent Document 2] Special Publication No. 2011-516373 [Patent Document 3] JP 2019-33021 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in recent years, the maximum summer temperature has been rising due to global warming, and in storage facilities without air conditioning, there are cases where settlement cannot be avoided with resin materials formulated according to conventional resin design guidelines. Even if air conditioning is fully equipped, there are concerns about unexpected power outages and increased costs due to power consumption during peak power hours.

[0008] Patent Document 1 is intended for circuit breakers and uses a resin consisting of an epoxy base resin, a hardener, and a reactive diluent, but the composition does not take measures to prevent settling.

[0009] In Patent Document 2, fumed silica is added as a thickener to an epoxy resin material, but no curing agent or radical monomer containing silica is included, and the aim is simply to thicken the epoxy resin.

[0010] Patent Document 3 is for circuit breakers and has in common the point of adding rubber particles to an epoxy resin, but the rubber particles are for improving crack resistance, and their size is 0.1 to 1 μm, and hydrophobic fumed silica is not added to improve thixotropy.

[0011] An object of the present invention is to improve the storage stability of molding resin for power receiving and distributing devices in a high-temperature environment and to increase the molding reliability. [Means for solving the problem]

[0012] The molding resin of one embodiment of the present invention for an electric power receiving / distribution device is a molding resin for sealing the electric power receiving / distribution device, and the raw material liquid of the molding resin includes a base liquid having epoxy resin and silica as main components, a hardener liquid having acid anhydride and silica as main components, and a reactive diluent liquid having radical monomer and copolymerization agent as main components, and the hardener liquid includes at least one of (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm, and (B) fumed silica having a hydrophobic surface. Effect of the Invention

[0013] According to one aspect of the present invention, the storage stability of the molding resin of a power receiving and transforming device in a high-temperature environment can be improved, and the molding reliability can be increased. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram showing the configuration of a power distribution device (vacuum circuit breaker). [Diagram 2] FIG. 2 is a diagram showing an example of mixing the components of a molding material, that is, an epoxy base agent, a curing agent, and a reactive diluent. [Diagram 3] FIG. 2 is a diagram showing an example of mixing the components of a molding material, that is, an epoxy base agent, a curing agent, and a reactive diluent. [Figure 4] FIG. 2 is a diagram showing an example of mixing the components of a molding material, that is, an epoxy base agent, a curing agent, and a reactive diluent. [Diagram 5] FIG. 2 is a diagram showing the characteristics of a cured material prepared by mixing a base agent, a curing agent, and a reactive diluent. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In an embodiment of the present invention, the resin raw materials constituting the molded part of the electric power receiving and transforming equipment are three kinds of molded resin raw material liquids consisting of a base liquid mainly composed of epoxy resin and silica, a hardener liquid mainly composed of acid anhydride and silica, and a reactive diluent liquid mainly composed of radical monomer and copolymerization material. Butadiene rubber or styrene butadiene rubber with a diameter of less than 100 nm and fumed silica whose surface hydroxyl groups are hydrophobized by methyl groups are added to the hardener liquid in a total amount of less than 2 weight percent. Then, the above three raw material liquids are mixed and hardened to form the molded part.

[0016] The raw resin is an epoxy agent that crosslinks with acid anhydrides to form a strong solid. However, it contains a large amount of silica particles (70 percent by weight), which makes it highly viscous. To alleviate this, a mixture of radical monomers and copolymers is added as a reactive diluent.

[0017] Reactive diluents have low viscosity, and because they do not contain fillers such as silica, they help to lower the viscosity of the mixture of the base agent and hardener and improve casting properties. In addition, the viscosity of the base agent and hardener is high at around 15 Pa·s at room temperature (25°C), but due to the recent rise in summer temperatures, temperatures can sometimes exceed 40°C in storage locations without air conditioning.

[0018] In such a temperature environment, the viscosity of the base resin and hardener when stored separately drops to about a few Pa·s, causing the fillers contained inside to settle. If the fillers settle to the bottom of the container, the supernatant liquid remaining at the top of the container will be used when the resin is used, which may reduce the fillers contained in the cured resin and reduce its strength and voltage resistance.

[0019] Therefore, in an embodiment of the present invention, butadiene rubber or styrene butadiene rubber particles with a diameter of less than 100 nm are added. These particles do not settle due to the action of molecular Brownian motion in the liquid, and unlike the polar base agent (epoxy) and curing agent (acid anhydride), they are non-polar substances and form a network structure in the liquid when stationary.

[0020] Due to this network structure, the viscosity of the liquid when stationary appears to be very high, and in the ideal case, it will become gel-like even at a high temperature of about 40°C. In this embodiment, it did not become gel-like, but the viscosity was such that a dent remained when pressed with a finger. This prevents the filler contained inside from settling.

[0021] On the other hand, once the liquid starts to move, this network structure is destroyed and the viscosity drops rapidly. Therefore, when the liquid starts to flow by tilting the container or stirring during use, the liquid viscosity drops to below 15 Pa·s. The addition of a radical monomer further reduces the viscosity to around 7 Pa·s, which does not impair handling during use.

[0022] In addition, due to the synergistic effect of the butadiene rubber and the styrene butadiene rubber with the hydrophobic fumed silica, it is possible to improve the viscosity at rest with a smaller amount added than when the rubber is used alone, as described below.

[0023] As described above, according to this embodiment, it is possible to improve storage properties so that the resin filler does not settle, and it also has the effect of preventing an increase in handling properties (kinetic viscosity) during use.

[0024] Preferably, only butadiene rubber or styrene-butadiene rubber is added, and the ratio is 5 weight percent or less. Both butadiene rubber and styrene-butadiene rubber are hydrophobic substances, and in polar epoxy resins or acid anhydrides, there is an effect of reducing the contact area with each other, similar to the separation of water and oil.

[0025] Furthermore, because these particles are minute particles, they do not settle due to the effects of Brownian motion, but instead bond together to create a network structure in the liquid. This network structure increases the viscosity of the liquid and inhibits the settling of the filler. The amount of additive can be about 5% by weight, but if it falls below 3% by weight, the ability to form a network structure is significantly lost and the viscosity at rest does not increase.

[0026] Preferably, only the surface-hydrophobized fumed silica is added, and the ratio of the surface-hydrophobized fumed silica may be 5 weight percent. The surface-hydrophobized silica acts as a hydrophobic substance in the liquid.

[0027] Therefore, as mentioned above, in polar epoxy resins or acid anhydrides, there is an effect that tries to reduce the contact area with each other, just like the separation of water and oil. Furthermore, the BET diameter of fumed silica is very small, about 20 nanometers, and these particles are fine particles, so they do not settle due to the influence of Brownian motion.

[0028] As a result, they bond together and create a network structure in the liquid. This network structure increases the viscosity of the liquid and inhibits the settling of the filler. The amount of addition can be about 5% by weight, but if it is less than 3% by weight, the ability to form a network structure is significantly lost and the viscosity at rest does not increase.

[0029] Preferably, as the hydrophobizing group of the fumed silica, the hydroxyl groups on the surface of the fumed silica may be replaced with alkyl groups such as ethyl groups or isobutyl groups instead of methyl groups.

[0030] These alkyl groups have no polarity, so by replacing them with highly polar hydroxyl groups, it is possible to make the fumed silica surface completely hydrophobic. This forms a network structure in the resin liquid, increasing the viscosity at rest and making it possible to suppress filler sedimentation.

[0031] Preferably, the epoxy resin of the resin raw material has a bisphenol A type skeleton or a bisphenol F type skeleton. Epoxy resins with a bisphenol A type skeleton are inexpensive and have high crack resistance and strength. Epoxy resins with a bisphenol F type skeleton are more expensive than bisphenol A type, but have a lower liquid viscosity than bisphenol A type, so they may be added to adjust the viscosity.

[0032] Preferably, the hardener for the resin raw material is an acid anhydride. Although amines are known as hardeners for epoxy resins in addition to acid anhydrides, acid anhydrides are preferred because of their mild reactivity.

[0033] Preferably, the radical monomer is styrene and the copolymerization agent is phenylmaleimide. Styrene is copolymerized with phenylmaleimide to form island-like radical polymerization regions in the epoxy resin, which contributes to toughening the cured product.

[0034] Preferably, imidazoles are contained as a reaction initiator for the epoxy resin and the acid anhydride. Imidazole has the effect of initiating polymerization using the epoxy ring of the epoxy resin as a reaction initiation point, and is one option for the reaction initiator.

[0035] Preferably, the reaction initiator for the radical monomer is an organic peroxide. The organic peroxide generates a radical active site by heating and plays a role in initiating radical polymerization. There are various types of peroxides, but organic peroxides that have mild reaction initiation properties and are highly safe are preferred.

[0036] According to an embodiment of the present invention, it is possible to improve the storage stability of the raw resin material of electric power distribution equipment, particularly vacuum circuit breakers, suppress settling of the filler contained in the resin material even during hot seasons such as summer, and prevent deterioration of the characteristics of the finished molded product.

[0037] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. EXAMPLES

[0038] The configuration of the power receiving and distributing device (vacuum circuit breaker) will be described with reference to FIG.

[0039] The vacuum circuit breaker body is located inside the dashed line 12, connected to a conductor rod 11, and sealed by hardened molded resin 10. The opening and closing of the vacuum circuit breaker 12 is controlled by an operating device 13. The role of the hardened molded resin 10 is to prevent the high electric field of the vacuum circuit breaker 12 from being directly exposed to the outside, to protect the circuit breaker from the surrounding environment, and to fix the various parts in place. It is therefore necessary for it to exhibit various properties such as strength, temperature resistance, and voltage resistance as designed. Therefore, any situation in which the composition of the resin material changes must be avoided.

[0040] However, the resin material (epoxy base, hardener) is filled with a filler (silica) that is up to 70 percent by weight, and a decrease in viscosity will cause the filler to settle. Silica, the main component of the filler, plays a role in ensuring the strength and dielectric breakdown strength of the cured molding resin, and if this content decreases, problems may occur, such as the mold being unable to withstand high electric fields and cracking, or being unable to withstand weight and vibration. The viscosity of the resin material decreases exponentially as the temperature increases, and storage in unexpected temperature conditions may impair the performance of the cured molding resin.

[0041] Therefore, in this embodiment, the components of the molding material, that is, the epoxy base agent, the hardener, and the reactive diluent, were mixed as shown in Figs. 2, 3, and 4.

[0042] First, the components of the base resin will be described. In this example, the viscosity of the epoxy base resin is high enough that it was thought that silica sedimentation would not occur, so in order to reduce the viscosity of the resin and improve handling, bisphenol F type epoxy resin was also used in addition to bisphenol A type. Depending on the application, bisphenol A type alone may be sufficient. The components of the base resin are listed below. The amounts (ratios) of each added are shown in Figure 2. 1) Liquid bisphenol A type epoxy resin, liquid bisphenol F type epoxy resin 2) Crystalline Silica 3) Fused Silica 4) Organic peroxide radical polymerization initiators

[0043] The base material had a sufficiently high viscosity with these components that it did not cause settling even at 40°C for 2400 hours. However, in order to prevent settling over a longer period, the fine styrene butadiene rubber, butadiene rubber, and hydrophobic fumed silica described in this example were each added at 1% by weight. In addition, surfactants and silane coupling agents were added at 2% by weight to improve manufacturability.

[0044] The main components of the reactive diluent are listed below, and the amounts of each added are shown in Figure 3. 1) N-Phenylmaleimide 2) Styrene 3) Polymerization inhibitor (4-tert-butylcatechol)

[0045] Reactive diluents do not contain silica. When reactive diluents are mixed with the highly viscous base resin and hardener, they reduce the viscosity of the entire liquid, improving casting properties. They also form islands of radical polymer hardened bodies in the epoxy resin, improving strength.

[0046] The main components of the hardener are listed below. The amounts of each added are shown in Figure 4. 1) Acid anhydride (3or4-methyl-1,2,3,6-tetrahydrophthalic anhydride) 2) Crystalline Silica 3) Fused Silica 4) Imidazole (epoxy resin reaction accelerator)

[0047] The viscosity of the curing agent in the above composition is low, and 5% of the total weight of the silica settled to the bottom at 40℃, 2400hr. For this reason, in this example, 1% by weight of styrene-butadiene rubber with a diameter of 80nm and 1% by weight of fumed silica, which has been hydrophobized by replacing the hydroxyl groups on the surface with methyl groups, were added. In addition, a total of 2% by weight of surfactants and silane coupling agents were added to improve manufacturability.

[0048] As mentioned above, by adding fine hydrophobic rubber and hydrophobic fumed silica, no settling occurred even when testing was carried out at 40℃ for 2400 hours. In addition, when the kinetic viscosity was measured once flow had begun, it was found to be 12 Pa·s, and although the viscosity was high and the filler was unlikely to settle when the liquid was stationary, it was found that there was no problem with fluidity once the liquid began to move. To give the liquid an initial flow, the container was tilted while stirring with the stirring blade, and a specified amount was added to the mixing container and measured and mixed.

[0049] The above-mentioned base resin, hardener, and reactive diluent were mixed to create a hardened product. The properties of the hardened product will be explained using Figure 5.

[0050] FIG. 5 shows that the addition of 2 weight percent total of fine rubber and hydrophobic fumed silica had little effect on important physical properties.

[0051] As described above, this example confirmed that the filler did not settle in the resin liquid even in a high-temperature environment. In addition, no adverse effects such as deterioration of physical properties due to the addition of the filler were observed. EXAMPLES

[0052] In Example 2, when the viscosity of the epoxy base resin is low and sedimentation occurs, the same effect can be achieved by adding a total of 2 weight percent of fine rubber particles with a diameter of less than 100 nm and hydrophobic fumed silica. Also, when the viscosity of both the epoxy base resin and the curing agent is low, the same effect can be achieved by adding fine rubber particles and hydrophobic fumed silica to both. EXAMPLES

[0053] In Example 3, the same effect was achieved even when only fine rubber particles with a diameter of less than 100 nm were added at 5 weight percent. However, when the amount of rubber added reaches 5 percent, the glass transition temperature tends to decrease. In Example 1, the glass transition temperature was 124°C, but in this example, it was 118°C. This is thought to be due to the effect of the added fine rubber. EXAMPLES

[0054] In Example 4, the same effect was achieved when only 5 weight percent of hydrophobic fumed silica was added. However, when the amount of hydrophobic fumed silica added reached 5 percent, the kinetic viscosity increased to 20 Pa·s. For this reason, mixing may become impossible in equipment equipped with a stirrer that does not have sufficient power (motor torque). In addition, the time required for vacuuming during degassing increased by about 20 percent. EXAMPLES

[0055] In Examples 1 and 4, the chemical groups introduced to hydrophobize the hydroxyl groups on the fumed silica surface were either isobutyl or ethyl, which produced the same effect. As long as the group was an alkyl group, it did not matter what group was used to replace the hydroxyl groups.

[0056] In this manner, the molding resin of the above embodiment is used to seal the power receiving and distributing device (for example, a vacuum circuit breaker).

[0057] The raw material liquid of the molding resin includes a base liquid mainly composed of epoxy resin and silica, a hardener liquid mainly composed of acid anhydride and silica, and a reactive diluent liquid mainly composed of radical monomer and copolymerization agent. The hardener liquid includes at least one of (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm, and (B) fumed silica having a hydrophobic surface.

[0058] In one aspect of the above embodiment (mold resin), the hardener liquid contains less than 2 weight percent in total of both (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm and (B) fumed silica having a hydrophobic surface.

[0059] In another aspect of the above embodiment (mold resin), the hardener liquid contains less than 5 weight percent of only the butadiene rubber or the styrene-butadiene rubber having a diameter of less than 100 nm (A).

[0060] In another aspect of the above embodiment (mold resin), the hardener liquid contains less than 5 weight percent of only the fumed silica (B) whose surface has been hydrophobized.

[0061] Moreover, the manufacturing method of the above embodiment manufactures power receiving and distributing equipment (for example, a vacuum circuit breaker) using a molding resin.

[0062] The raw material liquid of the molding resin includes a base liquid mainly composed of epoxy resin and silica, a hardener liquid mainly composed of acid anhydride and silica, and a reactive diluent liquid mainly composed of radical monomer and copolymerization agent. The hardener liquid includes at least one of (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm, and (B) fumed silica having a hydrophobic surface. The base liquid, the hardener liquid, and the hardener liquid are mixed and hardened to form the molding resin.

[0063] In one aspect of the above embodiment (production method), the curing agent liquid contains less than 2 weight percent in total of both (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm and (B) fumed silica having a hydrophobic surface.

[0064] In another aspect of the above embodiment (production method), the curing agent liquid contains less than 5 weight percent of only the butadiene rubber or the styrene-butadiene rubber having a diameter of less than 100 nm (A).

[0065] In another aspect of the above embodiment (production method), the hardener liquid contains less than 5 weight percent of only the fumed silica (B) whose surface has been hydrophobized.

[0066] According to the above embodiment, it is possible to prevent the settling of the filler contained in the resin material when the environmental temperature is high, such as in the summer, thereby improving the storage properties of the resin material, and to ensure the soundness of the hardened molded part when the power distribution equipment is molded with the resin material. [Explanation of symbols]

[0067] 10 Hardening molding resin 11 Conductor rod 12 Vacuum circuit breaker 13 Control device

Claims

1. A molding resin for sealing a power receiving and distributing device, The raw material liquid of the molding resin is A base liquid mainly composed of epoxy resin and silica, A hardener liquid mainly composed of acid anhydride and silica; A reactive diluent liquid containing a radical monomer and a copolymerization agent as main components; Including, The hardener liquid is (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm; (B) fumed silica having a hydrophobic surface; 13. A molding resin for a power receiving and distributing device, comprising at least one of the above.

2. The hardener liquid is (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm; (B) fumed silica having a hydrophobic surface; 2. The molding resin for an electric power receiving and distributing device according to claim 1, characterized in that the molding resin contains less than 2 weight percent of both of the above.

3. The hardener liquid is The molding resin for electric power receiving and distributing equipment according to claim 1, characterized in that (A) it contains less than 5 weight percent of the butadiene rubber or the styrene-butadiene rubber having a diameter of less than 100 nm.

4. The hardener liquid is 2. The molding resin for an electric power receiving and distributing device according to claim 1, characterized in that (B) the molding resin contains less than 5 weight percent of the fumed silica having a hydrophobic surface.

5. The hydroxyl groups on the surface of the fumed silica are 2. The molding resin for an electric power receiving and distributing device according to claim 1, characterized in that the group is a methyl group.

6. The hydroxyl groups on the surface of the fumed silica are 2. The molding resin for an electric power receiving and distributing device according to claim 1, characterized in that the molding resin is an alkyl group.

7. The alkyl group is 7. The molding resin for an electric power receiving and distributing device according to claim 6, characterized in that the molding resin is an ethyl group or an isobutyl group.

8. The epoxy resin is 2. The molding resin for an electric power receiving and distributing device according to claim 1, characterized in that it has a bisphenol A type skeleton or a bisphenol F type skeleton.

9. The hardener liquid is 2. The molding resin for an electric power receiving and distributing device according to claim 1, characterized in that the molding resin is an acid anhydride.

10. the radical monomer is styrene; 2. The molding resin for electric power receiving and distributing equipment according to claim 1, wherein the copolymerization agent is phenylmaleimide.

11. The raw material liquid of the molding resin is 2. The molding resin for electric power receiving and distributing equipment according to claim 1, further comprising an imidazole as a reaction initiator for the epoxy resin and the acid anhydride.

12. 2. The molding resin for electric power receiving and distributing equipment according to claim 1, wherein a reaction initiator for the radical monomer is an organic peroxide.

13. A power receiving and distributing device sealed with the molding resin according to claim 1.

14. The power distribution device according to claim 13, wherein the power distribution device is a vacuum circuit breaker.

15. A method for manufacturing an electric power receiving and distributing device using a mold resin, comprising the steps of: The raw material liquid of the molding resin is A base liquid mainly composed of epoxy resin and silica, A hardener liquid mainly composed of acid anhydride and silica; A reactive diluent liquid containing a radical monomer and a copolymerization agent as main components; Including, The hardener liquid is (A) butadiene rubber or styrene butadiene rubber having a diameter of less than 100 nm; (B) fumed silica having a hydrophobic surface; At least one of The method for manufacturing an electric power receiving and distributing device, comprising mixing the base liquid, the hardener liquid, and the hardener liquid and hardening the mixture to form the molded resin.

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