A high resistance anti-corona paint and its preparation method and insulation structure

Abstract

The invention relates to a high-resistance anti-corona paint and a preparation method and an insulating structure thereof, wherein the high-resistance anti-corona paint comprises water-based epoxy emulsion, silicon carbide, water-based epoxy curing agent and silicon dioxide. The mass ratio of water-based epoxy emulsion, silicon carbide, water-based epoxy curing agent and fumed silicon dioxide is 100: (150-200): (100-150): (0.1-2). The high-resistance anti-corona paint of the invention adopts a water-based resin system, has a low volatile organic matter content and does not contain volatile organic matter such as xylene or toluene, is more green and environmentally friendly, and the anti-corona coating wire rod or coil formed by the paint does not cause ablation, breakdown or flashover at a higher voltage (80kV), has good voltage resistance, is suitable for anti-corona treatment of hydropower and nuclear power generators of 20kV and above, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-corona paint, and in particular relates to a high-resistance anti-corona paint and a preparation method and an insulating structure thereof. Background Art

[0002] The development trend of motors is that the voltage level is getting higher and higher, and the capacity is getting larger and larger. The current highest voltage level of large hydropower is 24kV, and nuclear power is 27kV. Wind turbines are also conducting research on higher voltage levels. The high voltage level of the motor leads to uneven electric field distribution, which is prone to partial discharge and corona, thus shortening the service life of the motor. By coating a high-resistance anti-corona layer on the end of the coil or wire rod, the ablation of the insulation layer by the end discharge can be effectively reduced.

[0003] The existing high-resistance anti-corona paint suitable for high voltage levels is mainly imported and contains a large amount of organic volatiles (such as toluene, xylene, etc.). The presence of a large amount of organic volatiles will affect construction and cause environmental pollution and harm the health of workers. Therefore, there is an urgent need for an environmentally friendly high-resistance anti-corona paint with a high corona initiation voltage. Summary of the invention

[0004] The first object of the present invention is to provide a high-resistance anti-corona paint which is environmentally friendly and has a high corona inception voltage.

[0005] The second object of the present invention is to provide a method for preparing the high-resistance anti-corona paint.

[0006] The third object of the present invention is to provide an insulating structure containing the high-resistance anti-corona paint.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] On one hand, the present invention provides a high-resistance anti-corona paint, comprising water-based epoxy emulsion, silicon carbide, water-based epoxy curing agent and silicon dioxide, wherein the mass ratio of the water-based epoxy emulsion to the silicon carbide is 100:(150-200), the mass ratio of the water-based epoxy emulsion to the water-based epoxy curing agent is 100:(100-150), and the mass ratio of the water-based epoxy emulsion to the fumed silica is 100:(0.1-2); the water-based epoxy emulsion is prepared by mixing an organosilicon-modified epoxy resin, an emulsifier, water and an ether solvent, and the emulsifier is prepared by reacting an epoxy resin with polyethylene glycol; the high-resistance anti-corona paint does not contain xylene or toluene.

[0009] Preferably, the silicon carbide is α-type silicon carbide and / or β-type silicon carbide.

[0010] Preferably, the mesh number of the silicon carbide is 300 to 1000 meshes, and more preferably 400 to 700 meshes. The larger the mesh number of the silicon carbide, the more viscous the high-resistance anti-corona paint is, which affects the construction; the smaller the mesh number of the silicon carbide, the less conducive it is to form a dense silicon carbide layer, which has an adverse effect on the pressure resistance performance, therefore, it is preferably within the above range.

[0011] Preferably, the organosilicon-modified epoxy resin is prepared by reacting epoxy resin, acrylic acid, diphenyldihydroxysilane, 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine. By modifying the epoxy resin and introducing Si-O bonds therein, the flexibility of the high-resistance anti-corona paint can be improved, making the high-resistance anti-corona paint coating less prone to cracking; secondly, the heat resistance and anti-ultraviolet corrosion ability of the coating can be improved, thereby extending the service life of the coating.

[0012] In some embodiments, the mass ratio of epoxy resin, acrylic acid, diphenyldihydroxysilane, 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine in the silicone-modified epoxy resin is 100:(3-10):(1-5):(1-5):(0.01-0.5), and further is 100:(3-4):(2-3):(1-2):(0.03-0.5).

[0013] In some embodiments, the epoxy resin in the organosilicon-modified epoxy resin is selected from one or more of E44 epoxy resin, E51 epoxy resin, and F51 epoxy resin.

[0014] In some embodiments, the acid value of the organosilicon-modified epoxy resin is less than or equal to 3 mgKOH / g.

[0015] In some implementations, the organosilicon-modified epoxy resin is prepared by reaction at 120-130°C.

[0016] Preferably, the waterborne epoxy curing agent is prepared by reacting isophorone diamine, an epoxy mixture and o-cresyl glycidyl ether, and the epoxy mixture is a mixture of 1,3-bis(3-epoxypropyl)tetramethyldisilane and polyethylene glycol diglycidyl ether.

[0017] In some embodiments, the molar ratio of the isophorone diamine to the epoxy mixture is 2:(0.5-1.5), more preferably 2:(0.8-1.2), and most preferably 2:1.

[0018] In some embodiments, the mass ratio of the 1,3-bis(3-epoxypropyl)tetramethyldisilane to the polyethylene glycol diglycidyl ether is 100:(15-45), further 100:(20-40), and further 100:(25-35).

[0019] In some embodiments, the molar ratio of the o-cresyl glycidyl ether to the primary amine hydrogen of the isophorone diamine is 1:(1.1-1.2).

[0020] In some embodiments, the isophorone diamine, 1,3-bis(3-epoxypropyl)tetramethyldisilane, and polyethylene glycol diglycidyl ether are reacted at 60-65° C. for 3-5 hours, and then the o-tolyl glycidyl ether is added and reacted for 1-3 hours.

[0021] Furthermore, after the reaction is completed, the reaction product is diluted to obtain a water-based epoxy curing agent with a solid content of 45 to 55%.

[0022] Furthermore, the reaction product is diluted with water.

[0023] Preferably, the epoxy resin and polyethylene glycol are added in a molar ratio of hydroxyl group to epoxy group of 1:(1-1.5), and reacted in the presence of boron trifluoride ether to prepare the emulsifier.

[0024] In some implementations, the boron trifluoride etherate accounts for 0.01 to 0.5%, and further 0.1 to 0.3%, of the total mass of the epoxy resin and the polyethylene glycol.

[0025] Preferably, the mass ratio of the silicone-modified epoxy resin to the emulsifier is 100:(10-30), and more preferably 100:(20-30).

[0026] Preferably, the solid content of the aqueous epoxy emulsion is 40-60%.

[0027] Preferably, the ether solvent accounts for 5-10% of the total mass of the aqueous epoxy emulsion.

[0028] A second aspect of the present invention provides a method for preparing the high-resistance anti-corona paint as described above, comprising the following steps:

[0029] (1) reacting epoxy resin, acrylic acid, diphenyldihydroxysilane, 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine to prepare an organosilicon-modified epoxy resin;

[0030] (2) reacting epoxy resin with polyethylene glycol to prepare an emulsifier;

[0031] (3) mixing the emulsifier, the organosilicon-modified epoxy resin, water and an ether solvent to prepare a water-based epoxy emulsion;

[0032] (4) After the water-based epoxy emulsion and fumed silica are mixed and ground, silicon carbide is added and stirred evenly, and then a water-based epoxy curing agent is added and mixed evenly to prepare the high-resistance anti-corona paint.

[0033] Preferably, the reaction temperature of step (1) is 120-130°C.

[0034] Preferably, the reaction temperature of step (2) is 90-95°C.

[0035] Preferably, the solid content of the aqueous epoxy emulsion in step (3) is 40-60%.

[0036] A third aspect of the present invention provides an insulating structure, comprising an insulating layer formed on the surface of a wire rod or a coil and a high resistance layer formed outside the insulating layer, wherein the high resistance layer is formed by the high resistance anti-corona paint described above.

[0037] Preferably, the thickness of the high resistance layer is 0.15-0.5 mm.

[0038] Preferably, the high resistance layer is formed by brushing or spraying.

[0039] Preferably, the high resistance anti-corona paint is cured at 100-150° C. to form the high resistance layer.

[0040] More preferably, the curing temperature is controlled to be 110-130° C., and the curing time is 2-4 hours.

[0041] The high resistance layer provided by the invention has a surface resistivity of 30 to 800 GΩ at 2.5 kV, a surface resistivity of 0.06 to 10 GΩ at 5 kV, and a nonlinear coefficient of 1.6 to 3.

[0042] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0043] The high-resistance anti-corona paint adopts a water-based resin system, has a low volatile organic matter content and does not contain volatile organic matters such as xylene or toluene, is more environmentally friendly, and the anti-corona coating wire rod or coil formed by the paint does not cause ablation, breakdown or flashover at a higher voltage (80 kV, 1 min), has good voltage resistance, is suitable for anti-corona treatment of hydropower and nuclear power generators of 20 kV and above, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A cross-sectional view of the insulation structure provided by the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0046] Unless otherwise specified, the raw materials involved in the following examples and comparative examples are all commercially available products, or can be prepared by referring to existing preparation methods.

[0047] Unless otherwise specified, “parts” in the following examples and comparative examples refer to “parts by mass”.

[0048] Example 1

[0049] Preparation of silicone modified epoxy emulsion:

[0050] Epoxy resin E44 (purchased from Jiangsu Sanmu Chemical Co., Ltd.), acrylic acid, diphenyldihydroxysilane (diphenylsilanediol, CAS No.: 947-42-2), 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine were mixed in a mass ratio of 100:3:2:2:0.03, and reacted at 120°C to 130°C until the acid value was equal to 2.3 mgKOH / g to prepare a silicone epoxy resin.

[0051] Epoxy resin E51 (purchased from Jiangsu Sanmu Chemical Co., Ltd.) and PEG-6000 (purchased from Jiangsu Haian Petrochemical Factory) were added in a molar ratio of hydroxyl group to epoxy group of 1:1.2, and 0.1% of the total mass of E51 and PEG-6000 was added with boron trifluoride etherate. The reaction was carried out at a reaction temperature of 90°C to 95°C for 4 hours to prepare an emulsifier.

[0052] The above-mentioned emulsifier accounting for 20% of its mass is added to the above-mentioned silicone epoxy resin, and water and ethylene glycol methyl ether are gradually added at 70°C to 80°C and a high-speed disperser speed of 3000r / min. Emulsification is carried out for 30 minutes to prepare a silicone-modified epoxy emulsion with a solid content of 52% (wherein ethylene glycol methyl ether accounts for 8% of the total mass of the silicone-modified epoxy emulsion).

[0053] Preparation of high resistance anti-corona paint:

[0054] Take 100 parts of the above silicone modified epoxy emulsion, add 1 part of fumed silica H18 (purchased from Wacker, Germany), grind for 1 hour. Under stirring, add 150 parts of silicon carbide in batches, the silicon carbide is α-type, and the mesh size is 400 mesh. After all are added, stir for 30 minutes, then add 100 parts of water-based curing agent, stir for 30 minutes, and prepare high resistance anti-corona paint.

[0055] Among them, the preparation method of the water-based curing agent includes: mixing 2 mol of isophorone diamine and 1 mol of epoxy mixture (the epoxy mixture is prepared by mixing 1,3-bis(3-epoxypropyl)tetramethyldisilane and polyethylene glycol diglycidyl ether (purchased from Suzhou Senfida Chemical Co., Ltd., XY205) in a mass ratio of 100:30), reacting at 60-65° C. for 4 hours, adding o-cresyl glycidyl ether (o-cresyl glycidyl ether is 110% to 120% of the theoretical molar percentage of primary amine hydrogen), and diluting with water after reacting for 2 hours to obtain a solid content of (50±5)%.

[0056] Clean the surface of the wire rod, refer to Figure 1 The high-resistance anti-corona paint coating is attached to the surface of the insulating layer by brushing. The high-resistance layer and the low-resistance layer (the thickness of the low-resistance layer is 0.10 mm, the low-resistance layer paint model is JF-130A, purchased from Suzhou Jufeng Electrical Insulation System Co., Ltd.) overlap by 20 mm to 30 mm. The coating is baked at 120°C for 3 hours, and the thickness of the anti-corona layer (high-resistance layer) is 0.2 mm to 0.25 mm.

[0057] Example 2

[0058] The preparation of silicone-modified epoxy emulsion is the same as in Example 1.

[0059] The preparation of high resistance anti-corona paint is basically the same as in Example 1, except that the type and amount of silicon carbide and the amount used in the water-based curing agent are different, as follows:

[0060] In this embodiment, 200 parts of silicon carbide are added in batches, the silicon carbide is α-type and has a mesh size of 700 meshes; and 120 parts of a water-based curing agent are added.

[0061] Clean the surface of the wire rod, refer to Figure 1 The high-resistance anti-corona paint coating is attached to the surface of the insulating layer by brushing, and the coating is baked at 120°C for 3 hours. The thickness of the anti-corona layer is 0.4mm to 0.45mm.

[0062] Example 3

[0063] Preparation of silicone modified epoxy emulsion:

[0064] Epoxy resin F51 (purchased from Liyang Guowei Chemical Co., Ltd.), acrylic acid, diphenyldihydroxysilane, 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine were mixed in a mass ratio of 100:3:3:1:0.5, and reacted at 120°C to 130°C until the acid value was equal to 1.5 mgKOH / g to prepare a silicone epoxy resin.

[0065] E51 and PEG-6000 were added in a molar ratio of hydroxyl group to epoxy group of 1:1.5, and 0.2% of boron trifluoride etherate accounting for the total mass of E51 and PEG-6000 was added, and the reaction was carried out at a reaction temperature of 90° C. to 100° C. for 6 hours to prepare an emulsifier.

[0066] The above-mentioned emulsifier accounting for 30% of its mass is added to the above-mentioned silicone epoxy resin, and water and ethylene glycol methyl ether are gradually added at 80°C to 90°C and a high-speed disperser speed of 3500r / min, and emulsified for 30 minutes to prepare a silicone-modified epoxy emulsion with a solid content of 45% (wherein ethylene glycol methyl ether accounts for 10% of the total mass of the silicone-modified epoxy emulsion).

[0067] Preparation of high resistance anti-corona paint:

[0068] Take 100 parts of the above silicone modified epoxy emulsion, add 1 part of fumed silica H18, grind for 1 hour. Under stirring, add 170 parts of silicon carbide in batches, the silicon carbide is β-type, and the mesh size is 600 mesh. After all are added, stir for 30 minutes, then add 100 parts of water-based curing agent (refer to Example 1), stir for 30 minutes, and prepare high resistance anti-corona paint.

[0069] Clean the surface of the wire rod, refer to Figure 1 The high-resistance anti-corona paint coating is attached to the surface of the insulating layer by brushing. The coating is treated at 120°C for 3 hours, and the thickness of the anti-corona layer is 0.17mm to 0.25mm.

[0070] Comparative Example 1

[0071] The preparation method of the high-resistance anti-corona paint of this comparative example is basically the same as that of Example 1, except that the added amount of silicon carbide is 100 parts.

[0072] Comparative Example 2

[0073] The preparation method of the high-resistance anti-corona paint of this comparative example is basically the same as that of Example 1, except that the amount of silicon carbide added is 300 parts.

[0074] Comparative Example 3

[0075] The preparation method of the high resistance anti-corona paint of this comparative example is basically the same as that of Example 1, except that epoxy emulsion is used instead of silicone modified epoxy emulsion. The preparation method of epoxy emulsion is as follows:

[0076] To the epoxy resin E44, 20% of the mass of the emulsifier (see Example 1) was added, and water and ethylene glycol methyl ether were gradually added at 70°C to 80°C and a high-speed disperser speed of 3000 r / min, and emulsified for 30 minutes to prepare an epoxy emulsion with a solid content of 52%.

[0077] Comparative Example 4

[0078] The preparation method of the high resistance anti-corona paint in this comparative example is basically the same as that in Example 1, except that instead of using the organosilicon-modified epoxy emulsion, an E44 xylene solution with a solid content of 52% is used.

[0079] Comparative Example 5

[0080] The preparation method of the high-resistance anti-corona paint of this comparative example is substantially the same as that of Example 1, except that silicon oxide is used instead of silicon carbide.

[0081] Comparative Example 6

[0082] The preparation method of the high resistance anti-corona paint of this comparative example is substantially the same as that of Example 1, except that no emulsifier is used, and water and ethylene glycol methyl ether are directly added to the silicone epoxy resin.

[0083] Epoxy resin is insoluble in water and ethylene glycol methyl ether, the mixture separates into phases and cannot be used.

[0084] Performance test: The test method of 2.5kV surface resistivity and 5kV surface resistivity is based on GB / T31838.3-2019 Dielectric and resistance characteristics of solid insulating materials Part 3: Resistance characteristics (DC method) Surface resistance and surface resistivity; The calculation formula of the nonlinear coefficient (β) is: Wherein, ρ is the surface resistivity; the withstand voltage test method is to connect the high voltage end to the conductor of the wire rod, ground the low resistance layer of the wire rod, and test it on the power frequency withstand voltage instrument. There are 5 test samples in each embodiment.

[0085] Table 1

[0086]

[0087]

[0088] Referring to Table 1, the high-resistance anti-corona paint coating prepared in the present application has good voltage resistance, with no ablation, breakdown, or flashover at 80 kV and 1 min; and has better surface resistivity and nonlinear coefficient.

[0089] By comparing Example 1 with Comparative Examples 1 and 2, it is found that the amount of silicon carbide used is very important. If the amount is too little (such as Comparative Example 1), the silicon carbide layer formed on the surface of the coating cannot homogenize the surface electric field well when a high voltage is applied, and breakdown will occur; if the amount is too much, the silicone-modified epoxy emulsion cannot wrap all the silicon carbide, and the coating will crack, peel off, etc., affecting its use and also having an adverse effect on the voltage resistance performance.

[0090] Comparative Example 3 did not use silicone modification, and it turned yellow during the aging performance test (placed in a 155°C oven for 500 hours), which did not meet user requirements. However, the coating of the embodiment of the present application did not turn yellow, indicating that the high-resistance anti-corona paint coating prepared in the present application has better anti-aging performance.

[0091] The volatile organic matter of the high-resistance anti-corona paint of Comparative Example 4 reaches 300g / L, which is much greater than that of the embodiment of the present invention (the volatile organic matter of the embodiment is about 30g / L), which affects the construction and has an adverse effect on the health of operators and the environment, and is not environmentally friendly.

[0092] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A high resistance anti-corona paint, characterized in that: The high-resistance anti-corona paint comprises water-based epoxy emulsion, silicon carbide, water-based epoxy curing agent and silicon dioxide. Wherein, the mass ratio of the water-based epoxy emulsion to the silicon carbide is 100:(150-200), the mass ratio of the water-based epoxy emulsion to the water-based epoxy curing agent is 100:(100-150), and the mass ratio of the water-based epoxy emulsion to the fumed silica is 100:(0.1-2); The water-based epoxy emulsion is prepared by mixing an organosilicon-modified epoxy resin, an emulsifier, water and an ether solvent, and the emulsifier is prepared by reacting an epoxy resin with polyethylene glycol; The high-resistance anti-corona paint does not contain xylene or toluene.

2. The high resistance anti-corona paint according to claim 1, characterized in that: The silicon carbide is α-type silicon carbide and / or β-type silicon carbide; and / or, The mesh size of the silicon carbide is 300 to 1000 meshes.

3. The high resistance anti-corona paint according to claim 1, characterized in that: The organosilicon-modified epoxy resin is prepared by reacting epoxy resin, acrylic acid, diphenyldihydroxysilane, 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine.

4. The high-resistance anti-corona paint according to claim 3, characterized in that: The mass ratio of epoxy resin, acrylic acid, diphenyldihydroxysilane, 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine in the organosilicon-modified epoxy resin is 100:(3-10):(1-5):(1-5):(0.01-0.5); and / or, The epoxy resin in the organosilicon-modified epoxy resin is selected from one or more of E44 epoxy resin, E51 epoxy resin, and F51 epoxy resin; and / or, The acid value of the organosilicon-modified epoxy resin is less than or equal to 3 mgKOH / g.

5. The high-resistance anti-corona paint according to claim 1, characterized in that: The waterborne epoxy curing agent is prepared by reacting isophorone diamine, an epoxy mixture and o-cresyl glycidyl ether, wherein the epoxy mixture is a mixture of 1,3-bis(3-epoxypropyl)tetramethyldisilane and polyethylene glycol diglycidyl ether.

6. The high-resistance anti-corona paint according to claim 5, characterized in that: The molar ratio of the isophorone diamine to the epoxy mixture is 2:(0.5-1.5); The mass ratio of the 1,3-bis(3-epoxypropyl)tetramethyldisilane to the polyethylene glycol diglycidyl ether is 100:(15-45); The molar ratio of the o-cresyl glycidyl ether to the primary amine hydrogen of the isophorone diamine is 1:(1.1-1.2).

7. The high resistance anti-corona paint according to claim 1, characterized in that: The epoxy resin and the polyethylene glycol are added in a molar ratio of hydroxyl group to epoxy group of 1:(1-1.5), and reacted in the presence of boron trifluoride ether to prepare the emulsifier.

8. A method for preparing a high-resistance anti-corona paint according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) reacting epoxy resin, acrylic acid, diphenyldihydroxysilane, 3-(trimethoxysilyl)propyl methacrylate and triphenylphosphine to prepare an organosilicon-modified epoxy resin; (2) reacting epoxy resin with polyethylene glycol to prepare an emulsifier; (3) mixing the emulsifier, the organosilicon-modified epoxy resin, water and an ether solvent to prepare a water-based epoxy emulsion; (4) After the water-based epoxy emulsion and silicon dioxide are mixed and ground, silicon carbide is added and stirred evenly, and then a water-based epoxy curing agent is added and mixed evenly to prepare the high-resistance anti-corona paint.

9. The method for preparing the high resistance anti-corona paint according to claim 8, characterized in that: The reaction temperature of step (1) is 120-130° C.; and / or, The reaction temperature of step (2) is 90-95° C.; and / or, The solid content of the aqueous epoxy emulsion in step (3) is 40-60%.

10. An insulation structure, characterized in that: The insulating structure comprises an insulating layer formed on the surface of the wire rod or coil and a high resistance layer formed outside the insulating layer, wherein the high resistance layer is formed by the high resistance anti-corona paint according to any one of claims 1 to 7.

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