Alicyclic epoxy resin external insulation material with excellent hydrophobicity and preparation method thereof

Abstract

The invention relates to the technical field of electrical insulating materials for power transmission lines, and discloses an alicyclic epoxy resin external insulating material with excellent hydrophobicity and a preparation method thereof, the insulating material comprises the following raw material components: alicyclic epoxy resin, a curing agent, an accelerant and silicone rubber particles; the silicone rubber particles are subjected to plasma treatment. The alicyclic epoxy resin external insulation material with excellent hydrophobicity provided by the invention can effectively improve the hydrophobicity and hydrophobicity migration of the alicyclic epoxy resin material, and also can synergistically solve the problem of waste silicone rubber decommissioning treatment.

Description

Technical Field

[0001] The invention relates to the technical field of electrical insulation materials for power transmission lines, and in particular to an excellent hydrophobic alicyclic epoxy resin external insulation material and a preparation method thereof. Background Art

[0002] Ultra-high / UHV overhead transmission lines are the main arteries of power transmission and the basic support for my country to achieve clean energy transformation and the "3060" dual carbon goals. Insulators are an indispensable key component of overhead transmission lines, playing an important role in electrical isolation and mechanical connection. Silicone rubber composite insulators have gradually become the mainstream of high-voltage overhead transmission lines due to their light weight, convenient installation, and strong pollution flashover resistance. The current usage of various voltage levels has exceeded 10 million. However, under special operating environments such as high humidity and heat, strong wind and sand, and frequent bird activities, problems such as abnormal heating at the end of silicone rubber composite insulators, aging of the sheath-core rod interface, brittle core rod decay, and torn and damaged sheds frequently occur, seriously threatening the safe operation of the power grid and causing great trouble to the operation and maintenance units. Current research shows that the main reasons for the above problems are the high moisture permeability / water rate of the silicone rubber composite insulator sheath material, poor aging resistance of the sheath-core rod interface, and low mechanical strength of the sheath. On the other hand, the widespread use of silicone rubber composite insulators has also made the disposal of retired silicone rubber a thorny issue.

[0003] Due to its excellent water / moisture resistance, outstanding mechanical strength and outstanding interface aging resistance, alicyclic epoxy resin has become a potential way to solve the existing shortcomings of silicone rubber composite insulators under special operating environments. However, alicyclic epoxy resin is a polar molecule, and its cured product lacks hydrophobicity and hydrophobic migration, and cannot meet the requirements of external insulation for pollution resistance. Therefore, how to give alicyclic epoxy resin hydrophobicity and hydrophobic migration has become a key issue for the further promotion and application of this technology.

[0004] At present, there are two main methods to improve the hydrophobicity of alicyclic epoxy resins. One is to introduce elements such as silicone and fluorine into the molecular structure of epoxy resins through chemical synthesis to achieve hydrophobicity. However, this method is difficult to operate and difficult to prepare in large quantities. The other is to coat room temperature vulcanized silicone rubber (RTV) on the surface of epoxy resin to achieve hydrophobicity. However, this method has a macroscopic physical interface between the epoxy resin and the RTV coating. The interfacial bonding strength of the RTV coating is affected by the process and the operation of the construction personnel, and the macroscopic interface is prone to failure in harsh environments such as high humidity and heat, resulting in the coating falling off. Summary of the invention

[0005] Technical problems solved by the present invention:

[0006] The invention is used to solve the problems in the current methods for improving the hydrophobicity of alicyclic epoxy resins, such as high difficulty in operation and easy failure of interfaces when improving the hydrophobicity through coatings.

[0007] The technical solution adopted by the present invention is:

[0008] The excellent hydrophobic alicyclic epoxy resin external insulating material provided by the present application can effectively improve the hydrophobicity and hydrophobic migration of alicyclic epoxy resin materials, and can also collaboratively solve the problem of waste silicone rubber decommissioning. The existing waste silicone rubber composite insulator decommissioning treatment, if it is buried / incinerated, will cause serious environmental pollution and carbon emissions, if it is chemically degraded, it will lead to high costs and easy to produce polluting by-products. Based on this, the present application proposes an excellent hydrophobic alicyclic epoxy resin external insulating material and a preparation method. The method prepares the discarded silicone rubber material into micron-scale silicone rubber particles, and uses a plasma method to surface treat the silicone rubber particles to improve the compatibility of the silicone rubber particles with the epoxy resin. By doping silicone rubber particles in the epoxy resin, excellent hydrophobicity and hydrophobic migration are achieved. The method can also effectively recycle discarded silicone rubber insulator materials, promote the solution to the environmental protection problem of materials in the power industry, and realize a sustainable green development strategy.

[0009] To expand on this, that is to say:

[0010] The excellent hydrophobic alicyclic epoxy resin external insulating material provided by the invention comprises 90-120 parts of alicyclic epoxy resin, 70-90 parts of curing agent, 0.5-2 parts of accelerator and 20-30 parts of silicone rubber particles.

[0011] Further, the alicyclic epoxy resin includes at least one of 3,4-epoxycyclohexylmethyl, 3,4-epoxycyclohexylcarboxylate, bis((3,4-epoxycyclohexyl)methyl)adipate, tetrahydroindene diepoxide, 3,4-epoxycyclohexyl methacrylate and vinylcyclohexene dioxide.

[0012] Furthermore, the curing agent includes at least one of methylhexahydrophthalic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride.

[0013] Furthermore, the accelerator includes at least one of N,N-dimethylbenzylamine and 2,4,6-tris(dimethylaminomethyl)phenol.

[0014] Furthermore, the particle size of the silicone rubber particles is 1 to 20 μm.

[0015] Furthermore, the source of the silicone rubber particles includes at least one of retired silicone rubber composite insulator sheath materials and silicone rubber insulating materials.

[0016] Further, the processing method of the silicone rubber particles is that if the retired silicone rubber composite insulator umbrella material is used, the dirt and impurities on the surface are removed. If the discarded silicone rubber umbrella material after cleaning completely loses its hydrophobicity (the technicians in this field can judge by observing the contact angle of water droplets on the surface of the material; when the contact angle is significantly lower than 90 degrees, it indicates that the hydrophobicity is lost), the surface layer is cut off, leaving the silicone rubber component with good internal hydrophobicity. If new silicone rubber insulating material is used, the above steps are not required. Further, the cleaned silicone rubber block is cut into small pieces, put into a crusher, and initially crushed into smaller particles; the crushed particles are placed in a grinding device (such as a ball mill) for refinement until the particles reach the required particle size; the ground silicone rubber particles are graded using a screening device to screen out microparticles that meet the size requirements. The screening process may need to be performed multiple times to ensure the uniformity and size consistency of the particles. Use an appropriate solvent (such as a neutral detergent) to clean the screened microparticles again to remove impurities that may remain during the grinding process. The cleaned silicone rubber microparticles are dried to ensure that the particles are completely dry and there is no residual solvent.

[0017] Furthermore, the plasma treatment process is to place the silicone rubber particles in a plasma treatment instrument, set the output power to 500-1000W, the gas pressure to 0.1K-0.7MPa, and the treatment time to 0.5-5min.

[0018] Second, the present invention provides a method for preparing the aforementioned excellent hydrophobic alicyclic epoxy resin external insulating material, comprising the following steps:

[0019] The raw material components of the insulating material are weighed, mixed, and placed in a mold; then, they are solidified at a constant temperature, and then cooled and demolded to obtain the insulating material.

[0020] To elaborate, that is: the alicyclic epoxy resin, curing agent, accelerator and prepared silicone rubber particles are mixed together and fully stirred by a stirring disperser, the uniformly stirred mixture is poured into a mold, and the mold is evacuated to extract the residual air in the mixture, and then placed at room temperature for cooling and heat preservation for 2 to 5 hours;

[0021] High temperature curing of the mixture: the mold after cooling and heat preservation is placed in a constant temperature oven and maintained at 145℃~155℃ for 2.5~3.5 hours for primary curing, and then cooled to 115℃~120℃ for 6~8 hours for secondary curing; finally, the mold is demoulded after cooling to obtain the desired alicyclic epoxy material.

[0022] The preparation flow chart of the preparation method of the above-mentioned excellent hydrophobic alicyclic epoxy resin external insulation material is shown in Figure 1 The structural diagram of the obtained product is shown in Figure 2 .

[0023] The technical mechanism and beneficial effects adopted by the present invention are as follows:

[0024] (1) The insulating material provided by the present invention utilizes the excellent hydrophobicity and hydrophobic migration of silicone rubber composite materials to prepare discarded / retired silicone rubber insulator materials into microparticles and apply them to alicyclic epoxy resins through molecular diffusion and surface reconstruction, wherein the hydrophobic molecules migrate between the surface layers of the material through molecular diffusion, or under specific environmental stimulation, such as electric field action, cause surface reconstruction, thereby bringing the internal hydrophobic molecules to the surface. This self-recovery function significantly improves the reliability and service life of the alicyclic epoxy resin external insulating material in harsh environments.

[0025] (2) The insulating material provided by the present invention is prepared from waste / retired silicone rubber insulator materials into silicone rubber particles, and then prepared together with alicyclic epoxy resin, a curing agent, and an accelerator to obtain an insulating material. The method has simple operation, stable process, high preparation efficiency, and high qualified rate.

[0026] (3) The insulating material provided by the present invention performs plasma treatment on silicone rubber particles to activate the surface of the silicone rubber particles, thereby improving the interface compatibility between the silicone rubber particles and the epoxy resin, thereby improving the bonding strength and weather resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the preparation process of the insulating material provided by the present invention;

[0028] Figure 2 A schematic diagram of the product structure of the insulating material provided by the present invention;

[0029] Figure 3 A physical picture of the hydrophobicity test results of the insulating material provided in Example 1;

[0030] Figure 4 This is a physical picture of the hydrophobicity test results of the insulating material provided for Comparative Example 1. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0032] Example 1

[0033] An excellent hydrophobic alicyclic epoxy resin external insulating material comprises an alicyclic epoxy resin, an anhydride curing agent, an accelerator, and silicone rubber particles, wherein the alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl and 3,4-epoxycyclohexylcarboxylate, the anhydride curing agent is methyltetrahydrophthalic anhydride, the accelerator is N,N-dimethylbenzylamine, and the silicone rubber particles are obtained by grinding retired silicone rubber composite insulator umbrella cover materials, and the particle size is 1um-20um.

[0034] In this embodiment, the alicyclic epoxy resin is purchased from Jiangsu Taitel New Materials Technology Co., Ltd., model 184; the anhydride curing agent is selected from Guangzhou Shenchuang Chemical Co., Ltd.; the accelerator is selected from Shanghai McLean Biochemical Technology Co., Ltd.; the silicone rubber particles are selected from the scrapped silicone rubber composite insulators after retirement from the power grid company and obtained after grinding. The insulator manufacturer is Changyuan High Energy Co., Ltd.

[0035] The present embodiment provides a method for preparing an excellent hydrophobic alicyclic epoxy resin external insulating material, comprising the following steps:

[0036] (1) Preparation and processing of silicone rubber particles:

[0037] Step 1: Select the retired silicone rubber composite insulator umbrella cover material, first remove the dirt and impurities on its surface, and complete it by manual cleaning or mechanical brushing using warm water and appropriate neutral detergent.

[0038] Step 2: Observe whether the silicone rubber umbrella cover material has completely lost its hydrophobicity after cleaning, and judge by observing the contact angle of water droplets on the surface of the material. When the contact angle is significantly lower than 90 degrees, it indicates that the hydrophobicity has been lost. At this time, the surface layer should be cut off, and only the silicone rubber component with good hydrophobicity should be retained.

[0039] Step 3: Cut the cleaned silicone rubber block into small pieces, and then put it into a crusher for preliminary crushing to obtain smaller particles.

[0040] Step 4: Place the preliminarily crushed silicone rubber particles into a ball mill for refining until the particles reach the desired particle size (specifically 1-20 μm, for subsequent composite processing);

[0041] Step 5: Use screening equipment to classify the ground silicone rubber particles and screen out microparticles that meet the size requirements. The screening process needs to be performed multiple times to ensure the uniformity and size consistency of the particles.

[0042] Step six, select appropriate ethanol to perform secondary cleaning on the screened microparticles to remove tiny impurities and dust that may be attached during the grinding process.

[0043] Step seven, use a hot air drying oven to dry the cleaned silicone rubber microparticles to ensure that the particles are completely dry and free of any residual solvent.

[0044] Step 8: Place the ground silicone rubber particles in a low-temperature plasma treatment apparatus with an output power of 1000W, an air pressure of 0.1MPa, and a treatment time of 5min to activate the surface of the silicone rubber particles and enhance their compatibility with the epoxy resin.

[0045] (2) Raw material mixing preparation

[0046] 100 g of alicyclic epoxy resin, 78 g of curing agent, 1 g of accelerator and 20 g of prepared silicone rubber particles were mixed together, and the mixture was stirred thoroughly for 20 min at 50°C by heating in a water bath using a stirring disperser. The evenly stirred mixture was poured into a mold, and the mold was evacuated for 1 h to extract the residual air in the mixture until no obvious bubbles were generated.

[0047] (3) High temperature curing of the mixture

[0048] The mold is placed in a constant temperature oven and kept at 140°C for 3 hours for primary curing, then cooled to 120°C and kept at 120°C for 6 to 8 hours for secondary curing; finally, the mold is demoulded after cooling to obtain the desired alicyclic epoxy material.

[0049] Embodiment 2:

[0050] The difference between this embodiment and embodiment 1 is that the added amount of each component raw material is different, specifically, the mass parts of the alicyclic epoxy resin, anhydride curing agent, accelerator, and silicone rubber particle components are 100 parts, 90 parts, 2 parts, and 30 parts respectively.

[0051] Comparative Example 1:

[0052] The difference between this comparative example and Example 1 is that the silicone rubber particles are not subjected to plasma surface treatment.

[0053] Comparative Example 2:

[0054] The difference between this comparative example and Example 1 is that the particle size of the silicone rubber particles is greater than 20 μm.

[0055] Test Example 1:

[0056] The performance test was performed on the samples of Example 1-2 and Comparative Example 1-2, and the specific method is as follows:

[0057] (1) Hydrophobicity test: Use a contact angle meter to measure the water contact angle of different samples and evaluate their surface hydrophobicity.

[0058] (2) Electrical performance test: Test volume resistivity and AC breakdown strength according to GB / T1410-200 to evaluate the insulation performance of the material.

[0059] (3) Hydrophobicity migration test: The hydrophobicity of the material is evaluated by measuring its restored hydrophobicity after simulated environmental aging. The simulated conditions generally refer to UV aging, salt spray aging, etc.

[0060] (1) Hydrophobicity test results:

[0061] The samples of Example 1 and Example 2 showed relatively high water contact angles, and the average contact angles were both over 120 degrees, indicating excellent water repellency.

[0062] The water contact angle of the sample in Comparative Example 1 is relatively low because the silicone rubber particles have not been subjected to plasma surface treatment, and the water contact angle is about 100 degrees.

[0063] The water contact angle of the sample in Comparative Example 2 is also low, at about 95 degrees. This may be due to the large particle size of the silicone rubber particles, which affects the uniformity and stability of the hydrophobicity.

[0064] At the same time, the actual pictures of the hydrophobicity test results of Example 1 and Comparative Example 1 are provided, as shown in FIG. Figure 3-Figure 4 As shown, Figure 3 For the sample of Example 1, Figure 4 This is the sample of Comparative Example 1.

[0065] (2) Electrical performance test results:

[0066] The samples of Example 1 and Example 2 performed excellently in the electrical performance test, with high volume resistivity and high AC breakdown strength, which indicates that the materials have good insulation properties.

[0067] The volume resistivity of the samples of Comparative Example 1 and Comparative Example 2 is lower, and the AC breakdown strength is also reduced, indicating that the processing and particle size of the silicone rubber particles have a significant effect on the electrical properties.

[0068] (3) Hydrophobic migration test results:

[0069] The samples of Example 1 and Example 2 can recover their hydrophobicity relatively quickly after simulated environmental aging, showing good hydrophobic migration performance.

[0070] The samples of Comparative Example 1 and Comparative Example 2 have poor hydrophobic migration, long recovery time and poor recovery effect.

[0071] In summary, Example 1 and Example 2, which used plasma to treat silicone rubber particles and controlled their particle size within the range of 1-20 μm, had better hydrophobicity, electrical insulation and hydrophobic migration. Comparative Example 1 without plasma treatment and Comparative Example 2 with a larger particle size performed poorly in these performance tests, especially in terms of hydrophobicity and electrical properties. These results emphasize the importance of material processing during the preparation process and the key role of optimizing material properties in improving the performance of the final product.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An excellent hydrophobic alicyclic epoxy resin external insulating material, characterized in that: The raw material components include alicyclic epoxy resin, curing agent, accelerator and silicone rubber particles; the silicone rubber particles are treated with plasma.

2. The excellent hydrophobic alicyclic epoxy resin external insulating material according to claim 1, characterized in that: The particle size of the silicone rubber particles is 1 to 20 μm.

3. The excellent hydrophobic alicyclic epoxy resin external insulating material according to claim 1, characterized in that: The raw material components include 90-120 parts of alicyclic epoxy resin, 70-90 parts of curing agent, 0.5-2 parts of accelerator and 20-30 parts of silicone rubber particles by weight.

4. The excellent hydrophobic alicyclic epoxy resin external insulating material according to claim 1, characterized in that: The alicyclic epoxy resin includes at least one of 3,4-epoxycyclohexylmethyl, 3,4-epoxycyclohexylcarboxylate, bis((3,4-epoxycyclohexyl)methyl)adipate, tetrahydroindene diepoxide, 3,4-epoxycyclohexyl methacrylate, and vinylcyclohexene dioxide.

5. The excellent hydrophobic alicyclic epoxy resin external insulating material according to claim 1, characterized in that: The curing agent includes at least one of methylhexahydrophthalic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride.

6. The excellent hydrophobic alicyclic epoxy resin external insulating material according to claim 1, characterized in that: The accelerator includes at least one of N,N-dimethylbenzylamine and 2,4,6-tris(dimethylaminomethyl)phenol.

7. The excellent hydrophobic alicyclic epoxy resin external insulating material according to any one of claims 1 to 6, characterized in that: The source of the silicone rubber particles includes at least one of retired silicone rubber composite insulator sheath materials and silicone rubber insulating materials.

8. The excellent hydrophobic alicyclic epoxy resin external insulating material according to any one of claims 1 to 6, characterized in that: The plasma treatment process is to place the silicone rubber particles in a plasma treatment instrument, set the output power to 500-1000W, the gas pressure to 0.1K-0.7MPa, and the treatment time to 0.5-5min.

9. A method for preparing the excellent hydrophobic alicyclic epoxy resin external insulating material according to any one of claims 1 to 8, characterized in that: The steps include: The raw material components of the insulating material are weighed, mixed, and placed in a mold; then, they are solidified at a constant temperature, and then cooled and demolded to obtain the insulating material.

10. The method for preparing the excellent hydrophobic alicyclic epoxy resin external insulating material according to claim 9, characterized in that: Constant temperature curing includes stage one and stage two; Stage 1: Keep warm at 145-155℃ for 2.5-3.5h; Stage 2: Keep warm at 115-120℃ for 6-8h.

Images