Insulating resin material, electrical device, and method for manufacturing electrical device

Abstract

To stably reduce the viscosity of a raw material mixed liquid for an epoxy resin used for an electric apparatus in an insulating resin material.SOLUTION: The acid anhydride of the curing agent liquid contains hexahydrophthalic anhydride and 4-methylhexahydrophthalic anhydride, and the weight ratio of 4-methylhexahydrophthalic anhydride is equal to or more than that of hexahydrophthalic anhydride.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an insulating resin material, an electric device, and a method for manufacturing an electric device. [Background technology]

[0002] In power distribution equipment, particularly molded vacuum circuit breakers, in addition to the many metal parts, the ceramic circuit breaker valves must be resin molded.

[0003] Epoxy resins are often used for this purpose because they are low cost and have excellent physical properties. Epoxy resins used in electrical devices are usually copolymerized with acid anhydrides to improve the strength of the cured resin.

[0004] In addition, since a single type of acid anhydride compound may solidify at room temperature, a mixture of multiple acid anhydrides is used by chemical synthesis.

[0005] Related technologies include, for example, Patent Documents 1, 2, and 3. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-128621 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-188611 [Patent Document 3] Republished Publication No. 15 / 159781 Summary of the Invention [Problem to be solved by the invention]

[0007] Hardeners containing multiple acid anhydrides have low viscosity and are easy to handle when casting. However, when a mixture of two or more acid anhydrides is produced by synthesis without purification, the viscosity may vary depending on the production lot due to issues such as synthesis conditions.

[0008] Furthermore, simply configuring the curing agent from two or more compounds may not result in a sufficiently low viscosity.

[0009] An object of the present invention is to stably reduce the viscosity of a raw material mixture for epoxy resins used in electrical devices as insulating resin materials. [Means for solving the problem]

[0010] An insulating resin material according to one embodiment of the present invention is an insulating resin material for resin-molding electrical devices, and the raw material liquid of the insulating resin material contains a base liquid containing epoxy resin, silica, and core-shell rubber as its main components, a hardener liquid containing acid anhydride and silica as its main components, and a reactive diluent, wherein the acid anhydride in the hardener liquid is hexahydrophthalic anhydride and 4-methylhexahydrophthalic anhydride, and the weight ratio of the 4-methylhexahydrophthalic anhydride is the same as or greater than that of the hexahydrophthalic anhydride. [Effects of the Invention]

[0011] According to one aspect of the present invention, in an insulating resin material, it is possible to stably reduce the viscosity of a raw material mixture liquid for epoxy resins used in electrical devices. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a composition table of a curing agent. [Figure 2] FIG. 1 is a diagram showing a component list of an epoxy base agent. [Figure 3] FIG. 1 is a diagram showing a component list of reactive diluents. [Figure 4] 1 is a cross-sectional view of a molded circuit breaker, which is a power receiving and distribution device that uses insulating resin for electrical devices. [Figure 5] FIG. 10 is a flow chart for explaining the flow of a molding operation. DETAILED DESCRIPTION OF THE INVENTION

[0013] In an embodiment of the present invention, the resin raw materials constituting the molded portion of an insulating resin for an electrical device are a molded resin liquid made from a base liquid whose main components are epoxy resin, silica, and core-shell rubber, a hardener liquid whose main components are acid anhydride and silica, and a reactive diluent, in which the acid anhydrides in the hardener liquid are hexahydrophthalic anhydride and 4-methylhexahydrophthalic anhydride, and the weight ratio of 4-methylhexahydrophthalic anhydride is equal to or greater than that of hexahydrophthalic anhydride.

[0014] Preferably, the weight ratio of hexahydrophthalic anhydride (hereinafter abbreviated as HHPA) to 4-methylhexahydrophthalic anhydride (hereinafter abbreviated as 4-MeHHPA) is 1:1 or more, with 4-MeHHPA being blended in greater amounts.

[0015] In addition, silica and core-shell rubber are added to improve physical properties, and then a reactive diluent is added. This makes it possible to steadily reduce the viscosity of the resin mixture. Also, unlike regular diluents, reactive diluents harden inside the resin, so volatile components do not remain in the hardened mold, preventing deterioration of physical properties.

[0016] Preferably, the reactive diluent is styrene, vinyl toluene, vinyl monomers, acrylic esters, or a mixture thereof, more preferably a substance that copolymerizes with the reactive diluent. Vinyl toluene is expected to be a safer alternative to styrene.

[0017] Preferably, the reactive diluent is styrene and the copolymerization agent is phenylmaleimide. Styrene is highly chemically reactive, inexpensive, and has extremely low viscosity. Adding it to the epoxy base resin, curing agent, or a mixture of the two can stably reduce viscosity. Furthermore, adding phenylmaleimide as a copolymer produces a styrene-phenylmaleimide copolymer inside the cured mold, preventing liquid materials from remaining inside the mold and strengthening the mold.

[0018] Preferably, the epoxy resin base is an epoxy prepolymer having a bisphenol A skeleton or a bisphenol F skeleton, and the main filler is crystalline silica or fused silica.

[0019] Bisphenol A prepolymers are inexpensive and have excellent properties, while bisphenol F prepolymers can reduce the viscosity of the epoxy base resin. Depending on whether cost or low viscosity is important, you can create a resin mixture with the desired viscosity by using or mixing the two.

[0020] Preferably, the filler used is an acid anhydride in the curing agent, and is primarily crystalline silica or fused silica. The addition of crystalline silica increases the viscosity of the resin liquid more than the addition of fused silica, but it is relatively inexpensive (about one-fifth the cost of fused silica) and has excellent thermal conductivity. Therefore, incorporating crystalline silica within the required resin viscosity range reduces the cost of the resin material and improves thermal conductivity.

[0021] Preferably, the core-shell rubber has a core of styrene-butadiene rubber, nitrile rubber, silicone rubber or a mixture of the above rubbers, and only the surface layer is coated with polar groups.

[0022] Adding fine particle rubber such as core-shell has the effect of improving the fracture toughness (crack resistance) of the molded cured product. However, because the epoxy resin used in the base resin and the acid anhydride used in the curing agent both have polar groups, fine particle rubber made of materials such as styrene butadiene rubber has poor compatibility with the resin liquid and may precipitate or solidify.

[0023] This problem can be solved by using core-shell rubber, which consists of a core and a shell, with the outside of the rubber particles coated with polar groups. This is also effective in reducing viscosity, as the viscosity of the resin solution increases when the compatibility of rubber particles is low.

[0024] Preferably, the surface layer of the core-shell rubber is made up of vinyl, carboxyl, carbonyl, or hydroxyl groups. Rubber particles with inexpensive vinyl, carboxyl, carbonyl, or hydroxyl groups forming the shell on the core-shell surface are preferred. These have a proven track record of improving crack resistance, and their good compatibility with the resin mixture prevents precipitation and aggregation, preventing an increase in the viscosity of the resin liquid.

[0025] Preferably, the acid anhydride added to 4-methylhexahydrophthalic anhydride as the acid anhydride to be mixed with 4-methyltetrahydrophthalic anhydride may be tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 5-methyltetrahydrophthalic anhydride, 1-methyltetrahydrophthalic anhydride, tinfoil anhydride, or other cyclic acid anhydrides and their enantiomers.

[0026] This makes it possible to address structural issues with casting equipment and to provide an acid anhydride with a viscosity suited to the application and cost of the resin.

[0027] The present invention provides molded electrical substation equipment, particularly molded vacuum circuit breakers, manufactured using the materials described above. Even if the shape of a molded electrical substation using the resin is somewhat complex, the low viscosity of the resin allows for easy debubbling, particularly in vacuum casting, making it less likely to produce molding defects such as voids. Furthermore, the low viscosity of the resin during casting allows for easy injection of the resin into the mold, improving workability.

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0029] Figure 1 is a component list of the curing agent according to the present invention, and Figures 2 and 3 are component lists of the epoxy base resin and reactive diluent according to the present invention, respectively.

[0030] As shown in FIG. 1, the curing agent includes 4-methylhexahydrophthalic anhydride (4-MeHHPA), hexahydrophthalic anhydride (HHPA), crystalline silica, and fused silica.

[0031] As shown in FIG. 2, the epoxy base material includes bisphenol A epoxy prepolymer, bisphenol F epoxy prepolymer, crystalline silica, fused silica, core-shell rubber, and a polymerization initiator.

[0032] Reactive diluents include styrene (monomer), vinyltoluene, phenylmaleimide, and 4-methylhexahydrophthalic anhydride, as shown in Figure 3. As a substitute for styrene, vinyltoluene is expected to be safer.

[0033] As shown in Figure 1, the acid anhydride contains 4-MeHHPA and HHPA in a weight ratio of 60%:40%. Fused silica and crystalline silica are also included.

[0034] When a hardener was created based on this recipe, its viscosity was 8 Pa·s at 25°C. Furthermore, when the hardener, epoxy base resin, and reactive diluent were mixed in a weight ratio of 10:10:1 and the viscosity was measured at 60°C, it was 10 Pa·s. A total of five prototypes were made using this recipe, and mixed resin liquids were created and their viscosities were measured, revealing a consistently low value of 9.8 Pa·s to 10.2 Pa·s.

[0035] On the other hand, when the curing agent and epoxy base resin were mixed in a 10:10 ratio without adding a reactive diluent, the viscosity rose significantly, reaching over 20 Pa·s. With such a viscosity, it became extremely difficult to extract the resin at room temperature, making it unsuitable for use.

[0036] Furthermore, when the reactive diluent was changed to a vinyl monomer-based or acrylic ester-based one, the viscosity remained stable at approximately 11±0.2 Pa·s and 12±0.3 Pa·s, respectively. On the other hand, when the acid anhydride curing agent was synthesized all at once and a material containing multiple acid anhydrides was used, composition changes occurred that were thought to be due to differences in conditions in the acid anhydride synthesis process, and the resin viscosity fluctuated greatly between 8 Pa·s and 20 Pa·s.

[0037] When this composition was investigated by instrumental chemical analysis, it was found to contain at least four types of acid anhydride compounds, and that the composition and viscosity changed depending on the synthesis conditions. When such large fluctuations in viscosity occur, fine adjustments to the pouring temperature and speed are required when pouring the resin, and improper adjustments can lead to internal defects in the molded product.

[0038] As described above, according to Example 1, it is possible to stably reduce the viscosity and prepare a raw material resin liquid that is easy to handle. [Example]

[0039] FIG. 4 shows a cross-sectional view of a molded circuit breaker, which is a power receiving and distribution device using the insulating resin for electrical devices according to this embodiment.

[0040] The molded circuit breaker is composed of a vacuum circuit breaker valve 10, metal electrodes 11, molded resin 12, mechanical part 13, and operation terminals 14. The molded resin (hardened molded resin) 12 is manufactured using the raw resin liquid of Example 1. Here, the procedure for molding the valve 10, metal electrodes 11, and mechanical part 13 with the molded resin 12 will be explained. The materials prepared are 10 kg of an epoxy base resin with the composition shown in Figure 1, 10 kg of a hardener shown in Figure 2, and 1 kg of a reactive diluent shown in Figure 3.

[0041] The flow of the molding process will be described with reference to FIG.

[0042] First, the vacuum circuit breaker valve 10, the metal electrodes 11, the mechanical part 13, and the operation terminals 14 are fixed in a mold (step 501).

[0043] Next, with the parts assembled in the mold, the mold is heated to 80°C in a thermostatic chamber for 24 hours (step 502). Next, 10 kg of base resin and 10 kg of curing agent are heated to 60°C for 5 hours, and 1 kg of reactive diluent is heated to 60°C in a water bath for 0.5 hours (step 503).

[0044] Next, the base resin and curing agent are mixed in a mixer in a kneader, and then a reactive diluent is added and mixed for 30 minutes (step 504). Next, the pressure is reduced to 400 Pa in a vacuum tank and degassed (step 505).

[0045] Next, a resin liquid (mold resin liquid) is poured into a mold heated to 80° C. and vacuum-cast (step 506).

[0046] Finally, the resin liquid is hardened by a heat hardening process to form a mold resin (hardened mold resin) (step 507).

[0047] During the molding process, the core material (excluding the molded portion) shown in Figure 4 is placed in the mold, and the mold is heated to 80°C and the temperature is allowed to rise over 24 hours. Epoxy base resin A and acid anhydride B are placed in a tank and heated to 60°C over the course of about two hours. Once the mold and resin are sufficiently warmed, the base resin and hardener are mixed with a mixer while a vacuum is drawn to reduce the pressure to 400 Pa.

[0048] Once thoroughly mixed, add 1 kg of reactive diluent that has been preheated to 60°C in a hot water bath, then place in a tank and further vacuum degas at 400 Pa while stirring. Vacuum degassing takes about 10 minutes at 400 Pa. Once the mixture has been sufficiently degassed and the pressure has been reduced, it is poured into a mold (heated to 80°C) placed inside a vacuum chamber below the tank.

[0049] After confirming that the required amount has been injected, the mold containing the resin is placed in a thermostatic chamber preheated to 80°C and the resin is cured for approximately 8 hours. After this, the mold is removed and the resin is cured for 5 hours at 120°C.

[0050] This completes the molded circuit breaker shown in Figure 4. Finally, after checking for any bubbles or defects that may have occurred during molding, the product is sent to the shipping inspection department where shipping tests such as high voltage tests are carried out.

[0051] The probability of mold defects occurring in the resin prepared according to Example 2 was sufficiently low at less than 5 percent. When an acid anhydride curing agent, which causes fluctuations in resin viscosity, was used, defects were generated in up to 20 percent of molded products, but this high probability of defects was suppressed. The defects were void-like defects that occurred inside the mold, and were called void defects.

[0052] As described above, according to Example 2, the viscosity of the resin can be kept constant and low regardless of the resin manufacturing process, and manufacturing defects of the cast product (in this example, the molded circuit breaker) can be sufficiently reduced. [Example]

[0053] The same effect can be achieved even if the core-shell rubber described up to Example 2 is a rubber material having a core of styrene-butadiene rubber, nitrile rubber, silicone rubber, or a mixture of these rubbers, and having polar groups coated only on the surface layer. [Example]

[0054] The same effect can be achieved even if the surface layer of the core-shell rubber in Example 3 contains any one of vinyl groups, carboxyl groups, carbonyl groups, and hydroxyl groups, or a combination thereof. [Example]

[0055] The same effect can be achieved even if the acid anhydride added to 4-methylhexahydrophthalic anhydride in Example 1 is tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 5-methyltetrahydrophthalic anhydride, 1-methyltetrahydrophthalic anhydride, tlnadic anhydride, or any other cyclic acid anhydride or an enantiomer thereof. [Example]

[0056] Although the description has been given for molded circuit breakers in Examples 1 to 5, the same effect can be obtained for general electrical equipment. In particular, by using the material in molded insulators, motors, compressors, molded transformers, distribution boards, insulating boards for electrical circuits, etc., an improvement in the yield rate can be expected due to improved handling in the molding process.

[0057] According to the above-mentioned embodiment, it is possible to stably reduce the viscosity of the molding resin hardener, which improves the handling properties of the resin liquid mixture before hardening and improves the casting properties. This makes it difficult for defects to occur inside the molded product, and is expected to improve the yield rate of the product.

[0058] As described above, according to the above examples, by mixing two acid anhydrides in a predetermined ratio and then adding a reactive diluent, it is possible to achieve low viscosity and stabilize the viscosity, and further improve the handleability of the resin mixture and thereby improve the yield rate. [Explanation of symbols]

[0059] 10. Vacuum Circuit Breaker Valve 11 Metal electrode 12 Molding resin 13 Mechanical Department 14 Operation terminal

Claims

1. An insulating resin material for resin molding of electrical equipment, The raw material liquid of the insulating resin material is A base liquid whose main components are epoxy resin, silica, and core-shell rubber, a hardener liquid mainly composed of acid anhydride and silica; a reactive diluent; Including, The acid anhydride of the hardener liquid is Contains hexahydrophthalic anhydride and 4-methylhexahydrophthalic anhydride, An insulating resin material characterized in that the weight ratio of the 4-methylhexahydrophthalic anhydride is equal to or greater than that of the hexahydrophthalic anhydride.

2. The reactive diluent is 2. The insulating resin material according to claim 1, wherein the insulating resin material is selected from the group consisting of styrene, vinyl toluene, vinyl monomers, acrylic esters, and mixtures thereof.

3. The reactive diluent is 3. The insulating resin material according to claim 2, further comprising a copolymerization agent.

4. The reactive diluent is Styrene, 4. The insulating resin material according to claim 3, wherein the copolymerization agent is phenylmaleimide.

5. The epoxy resin is It is an epoxy prepolymer having a bisphenol A skeleton or a bisphenol F skeleton, The silica is 2. The insulating resin material according to claim 1, wherein the insulating resin material contains crystalline silica and fused silica as main fillers.

6. The silica in the hardener liquid is 2. The insulating resin material according to claim 1, wherein the insulating resin material contains crystalline silica and fused silica as main fillers.

7. The core-shell rubber of the main liquid component is 2. The insulating resin material according to claim 1, characterized in that the core is a rubber selected from the group consisting of styrene butadiene rubber, nitrile rubber, silicone rubber, and a mixture of said rubbers, and that only the surface layer is coated with polar groups.

8. The surface layer of the core-shell rubber is 8. The insulating resin material according to claim 7, which is composed of at least one of a vinyl group, a carboxyl group, a carbonyl group, and a hydroxyl group.

9. The acid anhydride to be added to the 4-methylhexahydrophthalic anhydride is 2. The insulating resin material according to claim 1, wherein the insulating resin material is any one of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 5-methyltetrahydrophthalic anhydride, 1-methyltetrahydrophthalic anhydride, tlnadic anhydride, and other cyclic acid anhydrides, or enantiomers thereof.

10. The viscosity of the insulating resin material at 60°C is 2. The insulating resin material according to claim 1, wherein the viscosity is in the range of 9.8 Pa·s to 10.2 Pa·s.

11. An electrical device that is resin-molded using an insulating resin material, The raw material liquid of the insulating resin material is A base liquid whose main components are epoxy resin, silica, and core-shell rubber, a hardener liquid mainly composed of acid anhydride and silica; a reactive diluent; Including, The acid anhydride of the hardener liquid is Contains hexahydrophthalic anhydride and 4-methylhexahydrophthalic anhydride, An electrical device characterized in that the weight ratio of the 4-methylhexahydrophthalic anhydride is equal to or greater than that of the hexahydrophthalic anhydride.

12. The electrical equipment includes:

12. The electrical device according to claim 11, which is a molded power receiving / transforming device.

13. The molded power receiving and transforming equipment is 13. The electrical device according to claim 12, which is a molded vacuum circuit breaker.

14. A method for manufacturing an electrical device using an insulating resin material, comprising: The raw material liquid of the insulating resin material is A base liquid whose main components are epoxy resin, silica, and core-shell rubber, a hardener liquid mainly composed of acid anhydride and silica; a reactive diluent; Including, The acid anhydride of the hardener liquid is Contains hexahydrophthalic anhydride and 4-methylhexahydrophthalic anhydride, The weight ratio of the 4-methylhexahydrophthalic anhydride is equal to or greater than that of the hexahydrophthalic anhydride, After mixing the base liquid, the hardener liquid, and the reactive diluent, the raw material liquid of the insulating resin material is hardened to form a molding resin; A method for manufacturing an electrical device, comprising resin-molding the electrical device with the molding resin.

15. 15. The method for manufacturing an electric device according to claim 14, wherein the molding resin is formed by injecting the raw material liquid of the insulating resin material into a heated mold.

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