A cast inorganic mineral insulated busbar

Abstract

This invention discloses a cast inorganic mineral-insulated busbar, comprising a busbar body and an inorganic mineral insulation layer disposed on the surface of the busbar body. The inorganic mineral insulation layer, by weight, comprises the following components: 48-56 parts silane-terminated polyether-modified epoxy resin, 16-22 parts terephthalate-coated scandium silicate / yttrium silicate microspheres, 15-20 parts quartz sand, 12-18 parts alumina, 5-10 parts neodymium oxide, 2-6 parts dispersant, 2-5 parts flame retardant, 0.5-1 part antioxidant, and 20-38 parts curing agent. This invention discloses a cast inorganic mineral-insulated busbar with an inorganic mineral insulation layer on the busbar surface, which exhibits good insulation properties, mechanical strength, high-temperature resistance, and corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of insulated busbars, and more specifically to a cast inorganic mineral insulated busbar. Background Technology

[0002] With the development of the national power industry, the capacity of main transformers in substations has increased, and the operating current on the secondary side of transformers has continued to rise. Busbars are one of the key pieces of equipment (materials) in power transmission and transformation systems, playing a crucial role in the safe and reliable operation of these systems and power equipment. They are mainly used in my country's power construction projects as conductor connections between power grid transmission lines and substation transformers, as jumpers in transmission lines, as connecting conductors in power equipment, and as overcurrent conductors in high-current DC de-icing devices. They are a completely new type of conductor, replacing traditional rectangular, slotted, and rod-shaped busbars and flexible conductors, and are one of the key pieces of equipment (materials) in power transmission and transformation systems, playing a crucial role in the safe and reliable operation of these systems and power equipment.

[0003] Existing cast iron busbars are difficult to meet electrical operation requirements in confined spaces and harsh environments. Although they can have good electrical insulation performance in the aforementioned restricted spaces, their mechanical strength and chemical resistance are poor, and their service life is short. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of this invention is to provide a cast inorganic mineral insulated busbar.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A cast inorganic mineral-insulated busbar includes a busbar body and an inorganic mineral insulation layer disposed on the surface of the busbar body; wherein, the inorganic mineral insulation layer comprises the following components by weight:

[0007] 48–56 parts silane-terminated polyether modified epoxy resin, 16–22 parts terephthalate-coated scandium silicate / yttrium silicate microspheres, 15–20 parts quartz sand, 12–18 parts alumina, 5–10 parts neodymium oxide, 2–6 parts dispersant, 2–5 parts flame retardant, 0.5–1 part antioxidant, and 20–38 parts curing agent.

[0008] Preferably, the thickness of the inorganic mineral insulating layer is 25–35 mm.

[0009] Preferably, the preparation method of the silane-terminated polyether modified epoxy resin is as follows:

[0010] S1. Weigh out bisphenol A type epoxy resin and silane-terminated polyether and mix them in anhydrous ethanol. After mixing evenly, heat to 65-80℃, reflux for 1-2 hours, and cool to room temperature to obtain the first epoxy resin mixture.

[0011] The mass ratio of bisphenol A type epoxy resin, silane-terminated polyether and anhydrous ethanol is 1:0.8-1.2:3-6.

[0012] S2. Weigh out bisphenol A type epoxy resin again, add organotin catalyst, mix evenly, heat to 65-80℃, stir for 2-4 hours, cool to room temperature, and obtain the second epoxy resin mixture.

[0013] The mass ratio of bisphenol A epoxy resin to organotin catalyst is 1:0.02 to 0.05.

[0014] S3. Mix the first epoxy resin mixture with the second epoxy resin mixture, then add polymethylphenylsiloxane, stir and mix evenly, and remove anhydrous ethanol to obtain silane-terminated polyether modified epoxy resin.

[0015] The mass ratio of the first epoxy resin mixture to the second epoxy resin mixture is 1:0.4 to 0.6.

[0016] Preferably, the molecular weight of the silane-terminated polyether is 10,000 to 20,000.

[0017] Preferably, the organotin catalyst is one of dibutyltin dilaurate, stannous octoate, and di(dodecyl sulfide)dibutyltin.

[0018] Preferably, the method for preparing the terephthalate-coated scandium silicate / yttrium silicate microspheres is as follows:

[0019] (1) Preparation of nano-scandium silicate / yttrium silicate:

[0020] S1. Weigh tetraethyl orthosilicate and mix with ethanol solution. After dispersing evenly, add a mixed solution of scandium chloride and yttrium chloride dropwise while stirring. After the addition is complete, continue stirring for 6 to 10 hours to obtain scandium silicate / yttrium silicate precursor.

[0021] The ethanol solution has a mass fraction of 35%–55%; the mixed solution of scandium chloride and yttrium chloride is obtained by mixing scandium chloride, yttrium chloride, and deionized water at a mass ratio of 1:0.23–0.36:4–6; the mass ratio of tetraethyl orthosilicate, ethanol solution, and the mixed solution of scandium chloride and yttrium chloride is 1:1.2–1.6:2.5–4.8.

[0022] S2. The scandium silicate / yttrium silicate precursor is first dried under reduced pressure, then placed in a reactor and heated to 900-1000℃. After holding at this temperature for 1-3 hours, the temperature is raised again to 1250-1400℃ and held for 2-4 hours. After naturally cooling to room temperature, it is ball-milled into nanoparticles to obtain nano-scandium silicate / yttrium silicate.

[0023] (2) Hydroxylated scandium silicate / yttrium silicate:

[0024] Weigh 3-[bis(2-hydroxyethyl)amino]propanetriethoxysilane and mix with deionized water. After dispersing evenly, add nano-scandium silicate / yttrium silicate, heat to 55-65℃, stir for 5-10 hours, centrifuge, wash the lower solid with pure water three times, and dry under reduced pressure to obtain hydroxylated scandium silicate / yttrium silicate.

[0025] The mass ratio of nano-scandium silicate / yttrium silicate, aminopropyltriethoxysilane, and deionized water is 1:0.1-0.3:5-8.

[0026] (3) Preparation of terephthalate-coated scandium silicate / yttrium silicate microspheres:

[0027] Hydroxylated scandium silicate / yttrium silicate was dispersed in N,N-dimethylformamide, terephthalic acid and phosphotungstic acid were added, the temperature was raised to 120-140℃, and the mixture was stirred for 4-6 hours. After filtration, the filter residue was washed and dried to obtain terephthalic acid ester-coated scandium silicate / yttrium silicate microspheres.

[0028] The mass ratio of hydroxylated scandium silicate / yttrium silicate, terephthalic acid, phosphotungstic acid and N,N-dimethylformamide is 1:0.53~0.65:0.03~0.06:5~10.

[0029] Preferably, the particle size of the nano-scandium silicate / yttrium silicate is 300-600 nm.

[0030] Preferably, the particle size of the quartz sand is 10–100 μm.

[0031] Preferably, the alumina has a particle size of 1–10 μm.

[0032] Preferably, the particle size of the neodymium oxide is 100–500 nm.

[0033] Preferably, the dispersant is polyethylene glycol.

[0034] Preferably, the antioxidant is one of diphenylphosphine, dimethyl phosphite, and dibenzyl phosphite.

[0035] Preferably, the flame retardant is an organophosphate flame retardant, including one or more of alkyl phosphates, condensed phosphates, and phenyl phosphates.

[0036] Preferably, the curing agent is N,N-diethyl-1,3-propanediamine or N-(2-hydroxyethyl)ethylenediamine.

[0037] Preferably, the method for preparing the cast inorganic mineral insulated busbar is as follows:

[0038] Step 1: Weigh out the silane-terminated polyether modified epoxy resin and dispersant according to the weight proportions, mix them, and after uniform dispersion, add terephthalate-coated scandium silicate / yttrium silicate microspheres, heat to 50-60℃, stir and mix for 0.5-1h, and then cool to room temperature to obtain the first mixture;

[0039] Step 2: Weigh out the quartz sand, alumina and neodymium oxide according to the weight proportions and mix them into the first mixture. After stirring and mixing evenly, add the flame retardant and antioxidant weighed out according to the weight proportions and mix evenly again to obtain the second mixture.

[0040] Step 3: Weigh the curing agent according to the weight proportions and add it to the second mixture. After thorough mixing, the epoxy resin casting mixture is obtained.

[0041] Step 4: After cleaning the busbar, place it in the casting mold and inject the epoxy resin casting mixture into the casting mold so that the epoxy resin casting mixture completely covers the busbar.

[0042] Step 5: Place the casting mold containing the busbar and epoxy resin casting mixture into the reaction furnace for curing. After demolding, the cast inorganic mineral insulated busbar is obtained.

[0043] Preferably, in step 4, the inside of the casting mold is coated with a release agent before the busbar is placed in.

[0044] Preferably, in step 4, ethanol or acetone is used for cleaning the busbar.

[0045] Preferably, in step 5, the temperature for curing in the reactor is first raised to 110-120°C, held for 2-3 hours, and then raised to 140-150°C and held for 1-2 hours.

[0046] The beneficial effects of this invention are as follows:

[0047] This invention discloses a cast inorganic mineral insulated busbar, wherein an inorganic mineral insulation layer is formed on the surface of the busbar. The inorganic mineral insulation layer has good insulation, mechanical strength, high temperature resistance and corrosion resistance.

[0048] Epoxy resin possesses advantages such as good insulation, corrosion resistance, dimensional stability, and adhesion, but it lacks high-temperature resistance and toughness. This invention first modifies it using silane-terminated polyether, then further modifies it by mixing it with terephthalate-coated scandium / yttrium silicate microspheres. The combination of these two methods increases the toughness and other mechanical properties of the epoxy resin. Finally, other additives are added to prepare an inorganic mineral insulating material cast onto the surface of the busbar.

[0049] The terephthalate-coated scandium / yttrium silicate microspheres prepared in this invention have a core-shell structure, meaning they are microspheres with nano-scandium / yttrium silicate as the core and terephthalate as the shell. The terephthalate shell enhances the crosslinking with silane-terminated polyether-modified epoxy resin, resulting in more uniform microsphere dispersion. It also modifies the silane-terminated polyether-modified epoxy resin. Unlike conventional preparations using single metal silicates, the combination of scandium and yttrium allows them to complement each other, achieving effects that neither metal alone can provide, such as higher strength or stability. As a core, it not only enhances mechanical properties but also improves thermal conductivity and flame retardancy. Detailed Implementation

[0050] The present invention will be further described below with reference to the following embodiments.

[0051] Example 1

[0052] A cast inorganic mineral insulated busbar includes a busbar body and an inorganic mineral insulation layer disposed on the surface of the busbar body; the thickness of the inorganic mineral insulation layer is 30 mm.

[0053] The inorganic mineral insulating layer, by weight, comprises the following components:

[0054] 52 parts of silane-terminated polyether modified epoxy resin, 18 parts of terephthalate-coated scandium silicate / yttrium silicate microspheres, 17 parts of quartz sand, 15 parts of alumina, 7 parts of neodymium oxide, 4 parts of polyethylene glycol, 3 parts of alkyl phosphate, 0.5 parts of diphenylphosphine oxide and 30 parts of N,N-diethyl-1,3-propanediamine.

[0055] The particle size of quartz sand is 10–100 μm; the particle size of alumina is 1–10 μm; and the particle size of neodymium oxide is 100–500 nm.

[0056] The preparation method of silane-terminated polyether modified epoxy resin is as follows:

[0057] S1. Weigh out bisphenol A type epoxy resin and silane-terminated polyether and mix them in anhydrous ethanol. After mixing evenly, heat to 75°C, reflux for 2 hours, and cool to room temperature to obtain the first epoxy resin mixture.

[0058] The molecular weight of the silane-terminated polyether is 10,000 to 20,000, and the mass ratio of bisphenol A epoxy resin, silane-terminated polyether and anhydrous ethanol is 1:1:4.

[0059] S2. Weigh out bisphenol A type epoxy resin again, add dibutyltin dilaurate, mix evenly, heat to 75°C, stir for 3 hours, cool to room temperature, and obtain the second epoxy resin mixture.

[0060] The mass ratio of bisphenol A epoxy resin to dibutyltin dilaurate is 1:0.03.

[0061] S3. Mix the first epoxy resin mixture with the second epoxy resin mixture, then add polymethylphenylsiloxane, stir and mix evenly, and remove anhydrous ethanol to obtain silane-terminated polyether modified epoxy resin.

[0062] The mass ratio of the first epoxy resin mixture to the second epoxy resin mixture is 1:0.5.

[0063] The preparation method of terephthalate-coated scandium silicate / yttrium silicate microspheres is as follows:

[0064] (1) Preparation of nano-scandium silicate / yttrium silicate:

[0065] S1. Weigh tetraethyl orthosilicate and mix with ethanol solution. After dispersing evenly, add a mixed solution of scandium chloride and yttrium chloride dropwise while stirring. After the addition is complete, continue stirring for 8 hours to obtain scandium silicate / yttrium silicate precursor.

[0066] The ethanol solution has a mass fraction of 45%; the mixed solution of scandium chloride and yttrium chloride is obtained by mixing scandium chloride, yttrium chloride and deionized water in a mass ratio of 1:0.28:5; the mass ratio of tetraethyl orthosilicate, ethanol solution and mixed solution of scandium chloride and yttrium chloride is 1:1.4:3.6.

[0067] S2. The scandium silicate / yttrium silicate precursor was first dried under reduced pressure, then placed in a reactor, heated to 1000℃, held for 2 hours, then heated to 1350℃ again, held for 3 hours, and then naturally cooled to room temperature. It was then ball-milled into nanoparticles with a particle size of 300-600 nm to obtain nano-scandium silicate / yttrium silicate.

[0068] (2) Hydroxylated scandium silicate / yttrium silicate:

[0069] Weigh 3-[bis(2-hydroxyethyl)amino]propanetriethoxysilane and mix with deionized water. After uniform dispersion, add nano-scandium silicate / yttrium silicate, heat to 60℃, stir for 8 hours, centrifuge, wash the lower solid with pure water three times, and dry under reduced pressure to obtain hydroxylated scandium silicate / yttrium silicate.

[0070] The mass ratio of nano-scandium silicate / yttrium silicate, aminopropyltriethoxysilane, and deionized water is 1:0.2:6.

[0071] (3) Preparation of terephthalate-coated scandium silicate / yttrium silicate microspheres:

[0072] Hydroxylated scandium silicate / yttrium silicate was dispersed in N,N-dimethylformamide, terephthalic acid and phosphotungstic acid were added, the temperature was raised to 130°C, and the mixture was stirred for 5 hours. After filtration, the filter residue was washed and dried to obtain terephthalic acid ester-coated scandium silicate / yttrium silicate microspheres.

[0073] The mass ratio of hydroxylated scandium silicate / yttrium silicate, terephthalic acid, phosphotungstic acid and N,N-dimethylformamide is 1:0.58:0.04:8.

[0074] The preparation method of cast inorganic mineral insulated busbars is as follows:

[0075] Step 1: Weigh out the silane-terminated polyether modified epoxy resin and polyethylene glycol according to the weight proportions, mix them evenly, add terephthalate-coated scandium silicate / yttrium silicate microspheres, heat to 55°C, stir and mix for 0.8 h, and then cool to room temperature to obtain the first mixture;

[0076] Step 2: Weigh out the quartz sand, alumina and neodymium oxide according to the weight parts and mix them into the first mixture. After stirring and mixing evenly, add the alkyl phosphate ester and diphenyl phosphate according to the weight parts and mix evenly again to obtain the second mixture.

[0077] Step 3: Weigh N,N-diethyl-1,3-propanediamine according to the weight proportions and add it to the second mixture. After thorough mixing, epoxy resin casting mixture is obtained.

[0078] Step 4: Take the busbar that has been cleaned with ethanol or acetone and place it in the casting mold. Coat the inside of the casting mold with a release agent before putting the busbar in. Inject the epoxy resin casting mixture into the casting mold so that the epoxy resin casting mixture completely covers the busbar.

[0079] Step 5: Place the casting mold containing the busbar and epoxy resin casting mixture into the reaction furnace, heat it to 115℃, keep it at that temperature for 2.5 hours, then heat it to 145℃ and keep it at that temperature for 2 hours. After demolding, you will get the cast inorganic mineral insulated busbar.

[0080] Example 2

[0081] A cast inorganic mineral insulated busbar includes a busbar body and an inorganic mineral insulation layer disposed on the surface of the busbar body; the thickness of the inorganic mineral insulation layer is 25 mm.

[0082] The inorganic mineral insulating layer, by weight, comprises the following components:

[0083] 48 parts silane-terminated polyether modified epoxy resin, 16 parts terephthalate coated scandium silicate / yttrium silicate microspheres, 15 parts quartz sand, 12 parts alumina, 5 parts neodymium oxide, 2 parts dispersant, 2 parts flame retardant, 0.5 parts antioxidant and 20 parts curing agent.

[0084] The particle size of quartz sand is 10–100 μm; the particle size of alumina is 1–10 μm; and the particle size of neodymium oxide is 100–500 nm.

[0085] The preparation method of silane-terminated polyether modified epoxy resin is as follows:

[0086] S1. Weigh out bisphenol A type epoxy resin and silane-terminated polyether and mix them in anhydrous ethanol. After mixing evenly, heat to 65°C, reflux for 1 hour, and cool to room temperature to obtain the first epoxy resin mixture.

[0087] The molecular weight of the silane-terminated polyether is 10,000 to 20,000, and the mass ratio of bisphenol A epoxy resin, silane-terminated polyether and anhydrous ethanol is 1:0.8:3.

[0088] S2. Weigh out bisphenol A type epoxy resin again, add stannous octoate, mix evenly, heat to 65-80℃, stir for 2-4 hours, cool to room temperature, and obtain the second epoxy resin mixture.

[0089] The mass ratio of bisphenol A epoxy resin to stannous octoate is 1:0.02.

[0090] S3. Mix the first epoxy resin mixture with the second epoxy resin mixture, then add polymethylphenylsiloxane, stir and mix evenly, and remove anhydrous ethanol to obtain silane-terminated polyether modified epoxy resin.

[0091] The mass ratio of the first epoxy resin mixture to the second epoxy resin mixture is 1:0.4.

[0092] The preparation method of terephthalate-coated scandium silicate / yttrium silicate microspheres is as follows:

[0093] (1) Preparation of nano-scandium silicate / yttrium silicate:

[0094] S1. Weigh tetraethyl orthosilicate and mix with ethanol solution. After dispersing evenly, add a mixed solution of scandium chloride and yttrium chloride dropwise while stirring. After the addition is complete, continue stirring for 6 hours to obtain scandium silicate / yttrium silicate precursor.

[0095] The ethanol solution has a mass fraction of 35%; the mixed solution of scandium chloride and yttrium chloride is obtained by mixing scandium chloride, yttrium chloride and deionized water in a mass ratio of 1:0.23:4; the mass ratio of tetraethyl orthosilicate, ethanol solution and mixed solution of scandium chloride and yttrium chloride is 1:1.2:2.5.

[0096] S2. The scandium silicate / yttrium silicate precursor was first dried under reduced pressure, then placed in a reactor, heated to 900℃, held for 1 hour, then heated to 1250℃ again, held for 2 hours, and then naturally cooled to room temperature. It was then ball-milled into nanoparticles with a particle size of 300-600 nm to obtain nano-scandium silicate / yttrium silicate.

[0097] (2) Hydroxylated scandium silicate / yttrium silicate:

[0098] Weigh 3-[bis(2-hydroxyethyl)amino]propanetriethoxysilane and mix with deionized water. After dispersing evenly, add nano-scandium silicate / yttrium silicate, heat to 55°C, stir for 5 hours, centrifuge, and wash the lower solid with pure water three times. Then dry under reduced pressure to obtain hydroxylated scandium silicate / yttrium silicate.

[0099] The mass ratio of nano-scandium silicate / yttrium silicate, aminopropyltriethoxysilane, and deionized water is 1:0.1:5.

[0100] (3) Preparation of terephthalate-coated scandium silicate / yttrium silicate microspheres:

[0101] Hydroxylated scandium silicate / yttrium silicate was dispersed in N,N-dimethylformamide, terephthalic acid and phosphotungstic acid were added, the temperature was raised to 120°C, and the mixture was stirred for 4 hours. After filtration, the filter residue was washed and dried to obtain terephthalic acid ester-coated scandium silicate / yttrium silicate microspheres.

[0102] The mass ratio of hydroxylated scandium silicate / yttrium silicate, terephthalic acid, phosphotungstic acid and N,N-dimethylformamide is 1:0.53:0.03:5.

[0103] The preparation method of cast inorganic mineral insulated busbars is as follows:

[0104] Step 1: Weigh out the silane-terminated polyether modified epoxy resin and polyethylene glycol according to the weight proportions, mix them evenly, add terephthalate-coated scandium silicate / yttrium silicate microspheres, heat to 50°C, stir and mix for 0.5 h, and then cool to room temperature to obtain the first mixture;

[0105] Step 2: Weigh out the quartz sand, alumina and neodymium oxide according to the weight parts and mix them into the first mixture. After stirring and mixing evenly, add the condensed phosphate ester and dimethyl phosphite weighed out according to the weight parts and mix evenly again to obtain the second mixture.

[0106] Step 3: Weigh N-(2-hydroxyethyl)ethylenediamine according to the weight proportions and add it to the second mixture. After thorough mixing, epoxy resin casting mixture is obtained.

[0107] Step 4: Take the busbar that has been cleaned with ethanol or acetone and place it in the casting mold. Coat the inside of the casting mold with a release agent before putting the busbar in. Inject the epoxy resin casting mixture into the casting mold so that the epoxy resin casting mixture completely covers the busbar.

[0108] Step 5: Place the casting mold containing the busbar and epoxy resin casting mixture into the reaction furnace, heat it to 110℃, keep it at that temperature for 2-3 hours, then heat it to 140℃ and keep it at that temperature for 1 hour. After demolding, you will get the cast inorganic mineral insulated busbar.

[0109] Example 3

[0110] A cast inorganic mineral insulated busbar includes a busbar body and an inorganic mineral insulation layer disposed on the surface of the busbar body; the thickness of the inorganic mineral insulation layer is 35 mm.

[0111] The inorganic mineral insulating layer, by weight, comprises the following components:

[0112] 56 parts of silane-terminated polyether modified epoxy resin, 22 parts of terephthalate-coated scandium silicate / yttrium silicate microspheres, 20 parts of quartz sand, 18 parts of alumina, 10 parts of neodymium oxide, 6 parts of polyethylene glycol, 5 parts of phenyl phosphate, 1 part of dibenzyl phosphite, and 38 parts of N,N-diethyl-1,3-propanediamine.

[0113] The particle size of quartz sand is 10–100 μm; the particle size of alumina is 1–10 μm; and the particle size of neodymium oxide is 100–500 nm.

[0114] The preparation method of silane-terminated polyether modified epoxy resin is as follows:

[0115] S1. Weigh out bisphenol A type epoxy resin and silane-terminated polyether and mix them in anhydrous ethanol. After mixing evenly, heat to 80°C, reflux for 2 hours, and cool to room temperature to obtain the first epoxy resin mixture.

[0116] The molecular weight of the silane-terminated polyether is 10,000 to 20,000, and the mass ratio of bisphenol A epoxy resin, silane-terminated polyether and anhydrous ethanol is 1:1.2:6.

[0117] S2. Weigh out bisphenol A type epoxy resin again, add di(dodecyl sulfide)dibutyltin, mix evenly, heat to 80°C, stir for 4 hours, cool to room temperature, and obtain the second epoxy resin mixture.

[0118] The mass ratio of bisphenol A type epoxy resin to di(dodecyl sulfide)dibutyltin is 1:0.05.

[0119] S3. Mix the first epoxy resin mixture with the second epoxy resin mixture, then add polymethylphenylsiloxane, stir and mix evenly, and remove anhydrous ethanol to obtain silane-terminated polyether modified epoxy resin.

[0120] The mass ratio of the first epoxy resin mixture to the second epoxy resin mixture is 1:0.6.

[0121] The preparation method of terephthalate-coated scandium silicate / yttrium silicate microspheres is as follows:

[0122] (1) Preparation of nano-scandium silicate / yttrium silicate:

[0123] S1. Weigh tetraethyl orthosilicate and mix with ethanol solution. After dispersing evenly, add a mixed solution of scandium chloride and yttrium chloride dropwise while stirring. After the addition is complete, continue stirring for 10 hours to obtain scandium silicate / yttrium silicate precursor.

[0124] The ethanol solution has a mass fraction of 55%; the mixed solution of scandium chloride and yttrium chloride is obtained by mixing scandium chloride, yttrium chloride and deionized water in a mass ratio of 1:0.36:6; the mass ratio of tetraethyl orthosilicate, ethanol solution and mixed solution of scandium chloride and yttrium chloride is 1:1.6:4.8.

[0125] S2. The scandium silicate / yttrium silicate precursor was first dried under reduced pressure, then placed in a reactor, heated to 1000℃, and kept at that temperature for 3 hours. After that, the temperature was raised to 1400℃ and kept at that temperature for 4 hours. After naturally cooling to room temperature, it was ball-milled into nanoparticles with a particle size of 300-600 nm to obtain nano-scandium silicate / yttrium silicate.

[0126] (2) Hydroxylated scandium silicate / yttrium silicate:

[0127] Weigh 3-[bis(2-hydroxyethyl)amino]propanetriethoxysilane and mix with deionized water. After uniform dispersion, add nano-scandium silicate / yttrium silicate, heat to 65℃, stir for 10 hours, centrifuge, wash the lower solid with pure water three times, and dry under reduced pressure to obtain hydroxylated scandium silicate / yttrium silicate.

[0128] The mass ratio of nano-scandium silicate / yttrium silicate, aminopropyltriethoxysilane, and deionized water is 1:0.3:8.

[0129] (3) Preparation of terephthalate-coated scandium silicate / yttrium silicate microspheres:

[0130] Hydroxylated scandium silicate / yttrium silicate was dispersed in N,N-dimethylformamide, terephthalic acid and phosphotungstic acid were added, the temperature was raised to 140°C, and the mixture was stirred for 6 hours. After filtration, the filter residue was washed and dried to obtain terephthalic acid ester-coated scandium silicate / yttrium silicate microspheres.

[0131] The mass ratio of hydroxylated scandium silicate / yttrium silicate, terephthalic acid, phosphotungstic acid and N,N-dimethylformamide is 1:0.65:0.06:10.

[0132] The preparation method of cast inorganic mineral insulated busbars is as follows:

[0133] Step 1: Weigh out the silane-terminated polyether modified epoxy resin and polyethylene glycol according to the weight proportions, mix them, disperse them evenly, add terephthalate-coated scandium silicate / yttrium silicate microspheres, heat to 60°C, stir and mix for 1 hour, and then cool to room temperature to obtain the first mixture;

[0134] Step 2: Weigh out the quartz sand, alumina and neodymium oxide according to the weight parts and mix them into the first mixture. After stirring and mixing evenly, add the phenyl phosphate ester and dibenzyl phosphite weighed out according to the weight parts and mix evenly again to obtain the second mixture.

[0135] Step 3: Weigh N,N-diethyl-1,3-propanediamine according to the weight proportions and add it to the second mixture. After thorough mixing, epoxy resin casting mixture is obtained.

[0136] Step 4: Take the busbar that has been cleaned with ethanol or acetone and place it in the casting mold. Coat the inside of the casting mold with a release agent before putting the busbar in. Inject the epoxy resin casting mixture into the casting mold so that the epoxy resin casting mixture completely covers the busbar.

[0137] Step 5: Place the casting mold containing the busbar and epoxy resin casting mixture into the reaction furnace, heat it to 120°C, keep it at that temperature for 3 hours, then heat it to 150°C and keep it at that temperature for 2 hours. After demolding, you will get the cast inorganic mineral insulated busbar.

[0138] Compare with Example 1

[0139] An inorganic mineral insulating layer is prepared in the same manner as in Example 1, except that:

[0140] The inorganic mineral insulating layer, by weight, comprises the following components:

[0141] 52 parts silane-terminated polyether modified epoxy resin, 18 parts dimethyl terephthalate, 17 parts quartz sand, 15 parts alumina, 7 parts neodymium oxide, 4 parts polyethylene glycol, 3 parts alkyl phosphate, 0.5 parts diphenylphosphine oxide and 30 parts N,N-diethyl-1,3-propanediamine.

[0142] Compare with Example 2

[0143] An inorganic mineral insulating layer is prepared in the same manner as in Example 1, except that:

[0144] The inorganic mineral insulating layer, by weight, comprises the following components:

[0145] 52 parts of polyether-modified epoxy resin (preparation method according to CN201510412424.3), 18 parts of dimethyl terephthalate, 17 parts of quartz sand, 15 parts of alumina, 7 parts of neodymium oxide, 4 parts of polyethylene glycol, 3 parts of alkyl phosphate, 0.5 parts of diphenylphosphine oxide and 30 parts of N,N-diethyl-1,3-propanediamine.

[0146] To more clearly illustrate the present invention, the inorganic mineral insulating layers prepared in Examples 1-3 and Comparative Examples 1-2 were compared in terms of performance. Tensile strength was tested according to standard ASTM D638-2014, and impact strength was tested according to standard GB / T 1843-2008. High-temperature resistance was tested by observing surface discoloration after being treated at 250°C for 1 hour. Acid corrosion resistance was tested by immersion in a 10% sulfuric acid solution for 120 hours, and alkali corrosion resistance was tested by immersion in a 10% sodium hydroxide solution for 120 hours, observing whether the surface was corroded. The results are shown in Table 1 below:

[0147] Table 1. Performance Comparison of Different Inorganic Mineral Insulating Layers

[0148] Compressive strength (MPa) 112 107 115 93 78 Impact strength (MPa) 31.8 30.5 32.6 25.8 20.2 High temperature resistance No color change No color change No color change Slight discoloration Severe discoloration Dielectric constant 7.12 6.98 7.10 6.77 6.51 Acid corrosion resistance No abnormalities No abnormalities No abnormalities Approximately 10% corrosion Approximately 20% corrosion Alkali corrosion resistance No abnormalities No abnormalities No abnormalities No abnormalities Approximately 10% corrosion

[0149] As shown in Table 1 above, the inorganic mineral insulating layers prepared in Examples 1 to 3 of the present invention have better mechanical strength (higher compressive strength and impact strength), high temperature resistance, insulation (higher dielectric constant) and acid and alkali corrosion resistance.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A cast inorganic mineral insulated busbar, characterized in that, It includes the busbar body and an inorganic mineral insulation layer disposed on the surface of the busbar body; wherein, the inorganic mineral insulation layer comprises, by weight, the following components: 48–56 parts silane-terminated polyether modified epoxy resin, 16–22 parts terephthalate-coated scandium silicate / yttrium silicate microspheres, 15–20 parts quartz sand, 12–18 parts alumina, 5–10 parts neodymium oxide, 2–6 parts dispersant, 2–5 parts flame retardant, 0.5–1 part antioxidant, and 20–38 parts curing agent; The preparation method of the silane-terminated polyether modified epoxy resin is as follows: S1. Weigh out bisphenol A type epoxy resin and silane-terminated polyether and mix them in anhydrous ethanol. After mixing evenly, heat to 65-80℃ and reflux for 1-2 hours. After cooling to room temperature, obtain the first epoxy resin mixture. The mass ratio of bisphenol A type epoxy resin, silane-terminated polyether and anhydrous ethanol is 1:0.8-1.2:3-6. S2. Weigh out the bisphenol A type epoxy resin again, add the organotin catalyst, mix evenly, heat to 65-80℃, stir for 2-4 hours, cool to room temperature, and obtain the second epoxy resin mixture; wherein, the mass ratio of bisphenol A type epoxy resin to organotin catalyst is 1:0.02-0.

05. S3. Mix the first epoxy resin mixture with the second epoxy resin mixture, then add polymethylphenylsiloxane, stir and mix evenly, remove anhydrous ethanol, and obtain silane-terminated polyether modified epoxy resin; wherein, the mass ratio of the first epoxy resin mixture to the second epoxy resin mixture is 1:0.4 to 0.

6. The method for preparing the terephthalate-coated scandium silicate / yttrium silicate microspheres is as follows: (1) Preparation of nano-scandium silicate / yttrium silicate: S1. Weigh tetraethyl orthosilicate and mix with ethanol solution. After uniform dispersion, add a mixed solution of scandium chloride and yttrium chloride dropwise while stirring. After the addition is complete, continue stirring for 6-10 hours to obtain the scandium silicate / yttrium silicate precursor. The mass fraction of the ethanol solution is 35%-55%. The mixed solution of scandium chloride and yttrium chloride is obtained by mixing scandium chloride, yttrium chloride and deionized water at a mass ratio of 1:0.23-0.36:4-6. The mass ratio of tetraethyl orthosilicate, ethanol solution and mixed solution of scandium chloride and yttrium chloride is 1:1.2-1.6:2.5-4.

8. S2. The scandium silicate / yttrium silicate precursor is first dried under reduced pressure, then placed in a reactor and heated to 900-1000℃. After holding at this temperature for 1-3 hours, the temperature is raised again to 1250-1400℃ and held for 2-4 hours. After naturally cooling to room temperature, it is ball-milled into nanoparticles to obtain nano-scandium silicate / yttrium silicate. (2) Hydroxylated scandium silicate / yttrium silicate: Weigh 3-[bis(2-hydroxyethyl)amino]propanetriethoxysilane and mix with deionized water. After uniform dispersion, add nano-scandium silicate / yttrium silicate, heat to 55-65℃, stir for 5-10 hours, centrifuge, wash the lower solid layer three times with pure water, and dry under reduced pressure to obtain hydroxylated scandium silicate / yttrium silicate; wherein the mass ratio of nano-scandium silicate / yttrium silicate, aminopropyltriethoxysilane and deionized water is 1:0.1-0.3:5-8; (3) Preparation of terephthalate-coated scandium silicate / yttrium silicate microspheres: Hydroxylated scandium silicate / yttrium silicate was dispersed in N,N-dimethylformamide, terephthalic acid and phosphotungstic acid were added, the temperature was raised to 120-140℃, and the mixture was stirred for 4-6 hours. After filtration, the filter residue was washed and dried to obtain terephthalic acid ester-coated scandium silicate / yttrium silicate microspheres. The mass ratio of hydroxylated scandium silicate / yttrium silicate, terephthalic acid, phosphotungstic acid and N,N-dimethylformamide was 1:0.53-0.65:0.03-0.06:5-10.

2. The cast inorganic mineral insulated busbar according to claim 1, characterized in that, The thickness of the inorganic mineral insulating layer is 25–35 mm.

3. The cast inorganic mineral insulated busbar according to claim 1, characterized in that, The molecular weight of the silane-terminated polyether is 10,000 to 20,000.

4. The cast inorganic mineral insulated busbar according to claim 1, characterized in that, The nano-scandium silicate / yttrium silicate has a particle size of 300–600 nm; the quartz sand has a particle size of 10–100 μm; the alumina has a particle size of 1–10 μm; and the neodymium oxide has a particle size of 100–500 nm.

5. A cast inorganic mineral insulated busbar according to claim 1, characterized in that, The dispersant is polyethylene glycol.

6. A cast inorganic mineral insulated busbar according to claim 1, characterized in that, The antioxidant is one of diphenylphosphine, dimethyl phosphite, and dibenzyl phosphite.

7. A cast inorganic mineral insulated busbar according to claim 1, characterized in that, The flame retardant is an organophosphate flame retardant, including one or more of alkyl phosphates, condensed phosphates, and phenyl phosphates.

8. A cast inorganic mineral insulated busbar according to claim 1, characterized in that, The method for preparing the cast inorganic mineral insulated busbar is as follows: Step 1: Weigh out the silane-terminated polyether modified epoxy resin and dispersant according to the weight proportions, mix them, and after uniform dispersion, add terephthalate-coated scandium silicate / yttrium silicate microspheres, heat to 50-60℃, stir and mix for 0.5-1h, and then cool to room temperature to obtain the first mixture; Step 2: Weigh out the quartz sand, alumina and neodymium oxide according to the weight proportions and mix them into the first mixture. After stirring and mixing evenly, add the flame retardant and antioxidant weighed out according to the weight proportions and mix evenly again to obtain the second mixture. Step 3: Weigh the curing agent according to the weight proportions and add it to the second mixture. After thorough mixing, the epoxy resin casting mixture is obtained. Step 4: After cleaning the busbar, place it in the casting mold and inject the epoxy resin casting mixture into the casting mold so that the epoxy resin casting mixture completely covers the busbar. Step 5: Place the casting mold containing the busbar and epoxy resin casting mixture into the reaction furnace for curing. After demolding, the cast inorganic mineral insulated busbar is obtained.