Anti-corona high-resistance paint as well as preparation method and application thereof

Abstract

The invention relates to anti-corona high-resistance paint and a preparation method and application thereof.The anti-corona high-resistance paint comprises a mixture A and a mixture B. The mixture A comprises, by mass, 15%-25% of epoxy resin, 50%-60% of silicon carbide, 0.1%-5% of graphene nanosheets, 0-0.5% of auxiliaries, 0.1%-1% of filler and 15%-25% of first organic solvent. The graphene nanosheet is prepared by dispersing expanded graphite in a second organic solvent and then performing microwave and ultrasonic dispersion; the mixture B comprises the following components in percentage by mass: 40-55% of polyamide resin, 42.5-60% of a third organic solvent and 0-2.5% of an auxiliary agent, wherein the total mass of the mixture B is 100%. The anti-corona high-resistance paint provided by the invention has the advantages of high resistance and high corona onset voltage, a high-resistance layer can be formed on the surface of a motor stator bar, the surface electric field intensity is reduced, and the occurrence probability of corona is reduced.

Description

Technical Field

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

[0002] At present, ultra-supercritical steam turbine generator sets with a rated voltage of 27kV and a rated power of 1000MW have been put into actual operation. In the above-mentioned units, anti-corona high-resistance paint is an important supporting material, which can effectively increase the corona inception voltage of stator bars and windings, effectively reduce the destructive effect of corona on the insulation structure, and ensure the safe service of the units.

[0003] As the rated voltage and rated capacity of generator sets continue to increase, the corona problem becomes more and more important, and the requirements for high-resistance paint become more and more stringent. Currently, the common high-resistance paint has the problem of low corona voltage, which is generally tested at a maximum of about 30kV after being made into wire rods. Summary of the invention

[0004] The purpose of the present invention is to provide an anti-corona high-resistance paint with high corona inception voltage and a preparation method and application thereof.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides an anti-corona high-resistance paint, comprising independently packaged mixture A and mixture B, wherein the total mass of the mixture A is 100%, the mixture A comprises the following components:

[0007] Epoxy resin 15%~25%,

[0008] Silicon carbide 50%~60%,

[0009] Graphene nanosheets 0.1% to 5%,

[0010] The first auxiliary agent is 0-0.5%,

[0011] Filler 0.1%~1%,

[0012] The first organic solvent is 15% to 25%,

[0013] The graphene nanosheets are prepared by dispersing expanded graphite in a second organic solvent and then dispersing the expanded graphite by microwave and ultrasound.

[0014] Taking the total mass of the mixture B as 100%, the mixture B includes the following components:

[0015] Polyamide resin 40%~55%,

[0016] The third organic solvent is 42.5% to 60%.

[0017] The second auxiliary agent is 0-2.5%.

[0018] Due to its unique two-dimensional structure and electronic properties, graphene nanosheets exhibit nonlinear conductivity characteristics under strong electric fields. By adding graphene nanosheets to anti-corona high-resistance paint, it has a synergistic effect with components such as silicon carbide, which can improve the corona inception voltage of the anti-corona layer made of high-resistance paint.

[0019] Preferably, the graphene nanosheets include a first graphene nanosheet and a second graphene nanosheet. The present invention finds that the second ultrasonic treatment time of the graphene nanosheets significantly affects the number of nanosheet layers, and the number of layers is closely related to the nonlinear behavior under a strong electric field. For those with a longer ultrasonic time, the thickness is thin and the nonlinear behavior is obvious, but the current resistance is limited in practice, and the anti-corona layer is easily ablated; for those with a short ultrasonic time, the opposite is basically true. Therefore, the present invention compounded the two for practical use to adjust the performance of the high-resistance paint. They are respectively called the first graphene nanosheet and the second graphene nanosheet.

[0020] In some embodiments, the preparation method of the first graphene nanosheet is as follows:

[0021] The expanded graphite is dispersed in the second organic solvent, ultrasonically dispersed for 0.5 h to 2 h, then subjected to microwave treatment for 1 min to 5 min, then ultrasonically dispersed for 4 h to 12 h, filtered, the filter residue is dissolved in toluene, and finally ultrasonically dispersed for 2 h to 6 h.

[0022] In some embodiments, the preparation method of the second graphene nanosheet is as follows:

[0023] The expanded graphite is dispersed in the second organic solvent, ultrasonically dispersed for 0.5 h to 2 h, then subjected to microwave treatment for 1 min to 5 min, then ultrasonically dispersed for 24 h to 30 h, filtered, the filter residue is dissolved in toluene, and finally ultrasonically dispersed for 2 to 6 h.

[0024] Preferably, the mass ratio of the first graphene nanosheet to the second graphene nanosheet is 1:(0.5-1.5), more preferably 1:(0.8-1.2), for example 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2.

[0025] In some implementations, the second ultrasonic dispersion of the first graphene nanosheets is controlled to last for 4 hours to 8 hours.

[0026] In some implementations, the ultrasonic power of the ultrasound is controlled to be 400W to 600W, and more preferably 450W to 550W.

[0027] In some implementations, the power of the microwave is controlled to be 600W to 800W, more preferably 650W to 750W.

[0028] Preferably, the mass content of the graphene nanosheets in the mixture A is 0.3% to 3%, for example, 0.3%, 1%, 1.5%, 2%, 2.5%, or 3%.

[0029] Preferably, the mesh size of the silicon carbide is 300-1000 meshes.

[0030] Further preferably, the silicon carbide consists of at least two types of silicon carbide with different mesh sizes.

[0031] In some embodiments, the silicon carbide includes a first silicon carbide, a second silicon carbide, a third silicon carbide, and a fourth silicon carbide, and the mesh number of the first silicon carbide is less than the mesh number of the second silicon carbide, less than the mesh number of the third silicon carbide, and less than the mesh number of the fourth silicon carbide.

[0032] Furthermore, the mesh number of the first silicon carbide is 300-350 meshes, the mesh number of the second silicon carbide is 360-500 meshes, the mesh number of the third silicon carbide is 750-850 meshes, and the mesh number of the fourth silicon carbide is 900-1100 meshes.

[0033] Furthermore, the mass ratio of the first silicon carbide, the second silicon carbide, the third silicon carbide and the fourth silicon carbide is (3-3.5): (2.5-3): (1.5-2): 1. By optimizing silicon carbide, the performance of the two-component anti-corona high-resistance paint can be further improved.

[0034] Preferably, the auxiliary agent is fumed silica.

[0035] Preferably, the filler is selected from one or more of acetylene black, graphite, quartz powder, zinc oxide, and red iron oxide.

[0036] Preferably, the first organic solvent and the third organic solvent are independently selected from one or more of toluene, butanol and acetone.

[0037] Preferably, the second organic solvent is selected from one or more of N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0038] Preferably, the epoxy resin is bisphenol A epoxy resin.

[0039] In some embodiments, the epoxy resin is selected from one or more of E-06, E-03, E-12, and E-20.

[0040] In some embodiments, the polyamide resin is selected from one or more of low molecular weight polyamide resins 600, 650, and 651.

[0041] Preferably, based on the total mass of the mixture A being 100%, the mixture A comprises the following components:

[0042] Epoxy resin 20%~25%,

[0043] Silicon carbide 52%~58%,

[0044] Graphene nanosheets 0.3% to 3%,

[0045] The first auxiliary agent is 0.05% to 0.2%,

[0046] Filler 0.5%~1%,

[0047] The first organic solvent is 20% to 25%.

[0048] Preferably, the second auxiliary agent includes a leveling agent, such as B-410 leveling agent.

[0049] More preferably, the mass proportion of the second auxiliary agent in the mixture B is 0.5% to 1.5%.

[0050] The second aspect of the present invention also provides a method for preparing the anti-corona high-resistance paint as described above, comprising the following steps:

[0051] (1) mixing an epoxy resin, a first auxiliary agent and a first organic solvent, and then adding silicon carbide, graphene nanosheets and fillers, and mixing them evenly to prepare a mixture A;

[0052] (2) The polyamide resin and the third organic solvent are mixed, and the second auxiliary agent is selectively added to prepare a mixture B.

[0053] The third aspect of the present invention also provides an application of the anti-corona high-resistance paint as described above, which comprises mixing mixture A and mixture B in a mass ratio of (10-15):1, then applying the mixture to the end of the wire rod, and forming an anti-corona layer after curing.

[0054] Preferably, the curing temperature is 20-30°C.

[0055] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0056] The anti-corona high-resistance paint provided by the present invention has the advantages of high resistance and high corona inception voltage, and can form a high-resistance layer on the surface of the motor stator wire rod, reduce the surface electric field strength, and thus reduce the probability of corona occurrence. DETAILED DESCRIPTION

[0057] 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.

[0058] 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.

[0059] Unless otherwise specified, the preparation method of the graphene nanosheet I hereinafter is as follows:

[0060] Take expanded graphite (YH-100, Qingdao Yanhai Carbon Material Co., Ltd.) 1g, dispersed in 100mL organic solvent (mixed by N, N-dimethylacetamide 80mL, N-methyl pyrrolidone 10mL, dimethyl sulfoxide 10mL), use 500W ultrasonic disperser to carry out ultrasonic dispersion 1h, then use 700W microwave to process the dispersed sample 1.5~3min, then use 500W ultrasonic disperser to carry out ultrasonic dispersion 4~8h, filter out organic solvent, change to equal quality toluene, finally use 500W ultrasonic disperser to carry out ultrasonic dispersion 4h, obtain the mixed solution containing graphene nanosheet I, the mixed solution can be used directly, also can be used after precipitation. The graphene nanosheet content in subsequent embodiments and comparative examples is all calculated according to solid, without toluene.

[0061] Unless otherwise specified, the preparation method of the graphene nanosheet II is as follows:

[0062] Take 1 g of expanded graphite (YH-100, Qingdao Yanhai Carbon Materials Co., Ltd.), disperse it in 100 mL of organic solvent (mixed by 80 mL of N,N-dimethylacetamide, 10 mL of N-methylpyrrolidone, and 10 mL of dimethyl sulfoxide), use a 500 W ultrasonic disperser for ultrasonic dispersion for 1 hour, then use a 700 W microwave to treat the dispersed sample for 1.5 to 3 minutes, and then use a 500 W ultrasonic disperser for ultrasonic dispersion for 24 to 30 hours, filter out the organic solvent, replace it with an equal mass of toluene, and then use a 500 W ultrasonic disperser for ultrasonic dispersion for 4 hours to obtain a mixed solution containing graphene nanosheets II. The mixed solution can be used directly or after desolventization.

[0063] Unless otherwise specified, the preparation method of the graphene nanosheet III hereinafter is as follows:

[0064] Take 1 g of expanded graphite (YH-100, Qingdao Yanhai Carbon Materials Co., Ltd.), disperse it in 100 mL of organic solvent (mixed by 80 mL of N,N-dimethylacetamide, 10 mL of N-methylpyrrolidone, and 10 mL of dimethyl sulfoxide), use a 500 W ultrasonic disperser for ultrasonic dispersion for 1 hour, then use a 700 W microwave to treat the dispersed sample for 1.5 to 3 minutes, and then use a 500 W ultrasonic disperser for ultrasonic dispersion for 10 to 12 hours, filter out the organic solvent, replace it with an equal mass of toluene, and then use a 500 W ultrasonic disperser for ultrasonic dispersion for 4 hours to obtain a mixed solution containing graphene nanosheets III, which can be used directly or after desolventization.

[0065] Example 1

[0066] A two-component anti-corona high-resistance paint is prepared according to the following steps:

[0067] Step 1, take 50 grams of toluene solvent and 50 grams of butanol solvent respectively, mix them evenly and use them as mixed solvent. Take 100 grams of bisphenol A epoxy resin E-20 (Jiangsu Sanmu Group Co., Ltd.) and 0.5 grams of fumed silica, disperse them in the mixed solvent to prepare resin varnish, add 100 grams of 320 mesh silicon carbide powder, 80 grams of 400 mesh, 50 grams of 800 mesh, and 30 grams of 1000 mesh, stir evenly, then add 3 grams of graphene nanosheets I, 3 grams of graphene nanosheets II, 2 grams of iron oxide red, and 1 gram of acetylene black, stir them with a high-speed stirrer for 2 to 3 hours to prepare resin component A.

[0068] Step 2: weigh 25 grams of toluene and 25 grams of butanol to make a mixed solvent, add 1 gram of B-410 leveling agent (Guangzhou Luou Trading Co., Ltd., polyether-modified silicone solution), weigh 40 grams of low molecular weight polyamide resin 600 (Jiangsu Sanmu Group Co., Ltd.), dissolve in the mixed solvent to prepare varnish, and prepare curing agent component B.

[0069] Step 3: During construction, mix the resin component A and the curing agent component B in a mass ratio of 10:1, apply with a roller, and dry at room temperature to obtain the anti-corona layer.

[0070] Example 2

[0071] It is basically the same as Example 1, except that the addition amounts of graphene nanosheets I and graphene nanosheets II are different.

[0072] In this embodiment, the added amount of graphene nanosheets I and graphene nanosheets II is 6 g each.

[0073] Example 3

[0074] It is basically the same as Example 1, except that the addition amounts of graphene nanosheets I and graphene nanosheets II are different.

[0075] In this embodiment, the added amount of graphene nanosheets I and graphene nanosheets II is 9 g each.

[0076] Example 4

[0077] It is basically the same as Example 1, except that the addition amounts of graphene nanosheets I and graphene nanosheets II are different.

[0078] In this embodiment, the added amount of graphene nanosheets I is 3 g, and the added amount of graphene nanosheets II is 0 g.

[0079] Example 5

[0080] It is basically the same as Example 1, except that the addition amounts of graphene nanosheets I and graphene nanosheets II are different.

[0081] In this embodiment, the added amount of graphene nanosheets I is 0 g, and the added amount of graphene nanosheets II is 3 g.

[0082] Example 6

[0083] It is basically the same as Example 1, except that: the graphene nanosheets I are replaced by graphene nanosheets III of equal mass.

[0084] Example 7

[0085] It is basically the same as Example 2, except that: the graphene nanosheets I are replaced by graphene nanosheets III of equal mass.

[0086] Example 8

[0087] It is basically the same as Example 1, except that the addition amounts of graphene nanosheets I and graphene nanosheets II are different.

[0088] In this embodiment, the added amount of graphene nanosheets I is 1 gram, and the added amount of graphene nanosheets II is 1 g.

[0089] Comparative Example 1

[0090] The method is basically the same as Example 1, except that 6 g of ordinary expanded graphite powder 100 mesh (YH-100, Qingdao Yanhai Carbon Material Co., Ltd.) is used to replace graphene nanosheets I and graphene nanosheets II.

[0091] Comparative Example 2

[0092] The method is basically the same as Example 1, except that the resin component A does not contain graphene nanosheets I and graphene nanosheets II.

[0093] Comparative Example 3

[0094] It is basically the same as Example 1, except that 6 g of commercially available graphene nanosheets (manufacturer is Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., brand name is XFQ022, product name is 99% pure nanoscale thin layer graphene nanosheets 1-6 nm) are used to replace graphene nanosheets I and graphene nanosheets II.

[0095] Performance test: A wire rod is made according to a rated voltage of 27kV, with a total length of 1850mm. The wire rod is impregnated and cured by the VPI process to form an insulating layer. The middle 500mm is brushed with low-resistance paint (brand JF-130A paint, purchased from Suzhou Jufeng Insulation System Co., Ltd.) to form a low-resistance anti-corona layer. The high-resistance paint in the above embodiment or comparative example is brushed symmetrically outward at both ends. The length of the overlapping part is 25mm, and the total length of the high-resistance paint is 620mm to form a high-resistance anti-corona layer with a thickness of 200-300μm. Electrode tests are made at the low-resistance part and the end of the wire rod to test the corona initiation voltage. The test results are shown in Table 1.

[0096] Table 1

[0097]

[0098] As can be seen from Table 1, adding ordinary expanded graphite to the high-resistance paint does not help improve its corona inception voltage, adding graphene nanosheets can improve the corona inception voltage of the high-resistance paint, but the improvement of the corona inception voltage by commercially available graphene nanosheets is not obvious. The present invention further improves the corona inception voltage of the high-resistance paint by optimizing the preparation method of the graphene nanosheets and using the compound of two graphene nanosheets.

[0099] 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. An anti-corona high resistance paint, characterized in that: Comprising independently packaged mixture A and mixture B, with the total mass of the mixture A being 100%, the mixture A comprises the following ingredients: Epoxy resin 15%~25%, Silicon carbide 50%~60%, Graphene nanosheets 0.1% to 5%, The first auxiliary agent is 0-0.5%, Filler 0.1%~1%, The first organic solvent is 15% to 25%, The graphene nanosheets are prepared by dispersing expanded graphite in a second organic solvent and then dispersing the expanded graphite by microwave and ultrasound. Taking the total mass of the mixture B as 100%, the mixture B includes the following components: Polyamide resin 40%~55%, The third organic solvent is 42.5% to 60%, The second auxiliary agent is 0-2.5%.

2. The anti-corona high-resistance paint according to claim 1, characterized in that: The graphene nanosheet comprises a first graphene nanosheet and a second graphene nanosheet, The preparation method of the first graphene nanosheet is as follows: Dispersing the expanded graphite in the second organic solvent, ultrasonically dispersing for 0.5 h to 2 h, then subjecting it to microwave treatment for 1 min to 5 min, then ultrasonically dispersing it for another 4 h to 12 h, filtering it, dissolving the filter residue in toluene, and finally ultrasonically dispersing it for another 2 to 6 h; The preparation method of the second graphene nanosheet is as follows: The expanded graphite is dispersed in the second organic solvent, ultrasonically dispersed for 0.5 h to 2 h, then subjected to microwave treatment for 1 min to 5 min, then ultrasonically dispersed for 24 h to 30 h, filtered, the filter residue is dissolved in toluene, and finally ultrasonically dispersed for 2 to 6 h.

3. The anti-corona high-resistance paint according to claim 2, characterized in that: The mass ratio of the first graphene nanosheet to the second graphene nanosheet is 1:(0.5-1.5).

4. The anti-corona high-resistance paint according to claim 2, characterized in that: Controlling the second ultrasonic dispersion time of the first graphene nanosheets to be 4 hours to 8 hours; and / or, Controlling the ultrasonic power of the ultrasound to be 400W to 600W; and / or, The power of the microwave is controlled to be 600W-800W.

5. The anti-corona high resistance paint according to claim 1, characterized in that: The mass content of the graphene nanosheets in the mixture A is 1% to 3%.

6. The anti-corona high resistance paint according to claim 1, characterized in that: The mesh size of the silicon carbide is 300 to 1000 meshes.

7. The anti-corona high resistance paint according to claim 1, characterized in that: The first auxiliary agent is fumed silica; and / or, The filler is selected from one or more of acetylene black, graphite, quartz powder, zinc oxide, and red iron oxide; and / or, The first organic solvent and the third organic solvent are independently selected from one or more of toluene, butanol and acetone; and / or, The second organic solvent is selected from one or more of N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

8. The anti-corona high resistance paint according to claim 1, characterized in that: The epoxy resin is bisphenol A type epoxy resin.

9. The method for preparing the anti-corona high-resistance paint according to any one of claims 1 to 8, characterized in that: The steps include: (1) mixing an epoxy resin, a first auxiliary agent and a first organic solvent, and then adding silicon carbide, graphene nanosheets and fillers, and mixing them evenly to prepare a mixture A; (2) The polyamide resin and the third organic solvent are mixed, and the second auxiliary agent is selectively added to prepare a mixture B.

10. The use of the anti-corona high resistance paint according to any one of claims 1 to 8, characterized in that: Mixture A and mixture B are mixed in a mass ratio of (10-15):1, and then applied to the end of the wire rod to form an anti-corona layer after curing.

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