A plasma-resistant etch-resistant insulating dielectric substrate and its preparation method

Abstract

This invention relates to the field of high-voltage discharge insulating dielectric substrate technology, and more particularly to a plasma-resistant insulating dielectric substrate and its preparation method, comprising the following steps: S1, grinding the insulating dielectric substrate and preparing a thin film material; S2, spraying the thin film material onto the insulating dielectric substrate; S3, heat treatment to obtain the finished product. The method of roughening the surface of the insulating dielectric substrate and then spraying the thin film in this invention effectively protects the insulating dielectric substrate material from plasma etching and high-voltage breakdown.

Description

Technical Field

[0001] This invention relates to the technical field of insulating dielectric substrates, and more particularly to a plasma-resistant insulating dielectric substrate and its preparation method. Background Technology

[0002] Low-temperature plasma technology is an interdisciplinary technology integrating physics, chemistry, biology, and environmental science, and it has been widely used in air purification, disinfection, and deodorization. Its significant advantages include physical, chemical, and biological effects on pollutants, low energy consumption, high efficiency, and no secondary pollution. Its purification mechanism involves two aspects: First, during plasma generation, the high-frequency discharge generates instantaneous high energy that breaks the chemical bonds within some harmful gas molecules, decomposing them into single-element atoms or harmless molecules. Second, the plasma contains a large number of high-energy electrons, positive and negative ions, excited-state particles, and highly oxidizing free radicals. These active particles collide and combine with some odor molecules, and under the influence of an electric field, the odor molecules are excited. When the energy gained by the odor molecules exceeds their bond energy, the chemical bonds of the odor molecules break, directly decomposing into single-element atoms or harmless gas molecules composed of single atoms. Simultaneously, a large number of active free radicals such as ·OH, ·HO2, and ·O, as well as highly oxidizing O3, are generated, reacting chemically with harmful gas molecules to ultimately produce harmless products.

[0003] In low-temperature plasma, dielectric barrier discharge (DBD) plasma technology is the most widely used. Structurally, a DBD device mainly consists of an insulating dielectric plate and two discharge electrodes. The necessary condition for plasma generation is the use of a high-voltage-resistant and dielectrically stable insulating dielectric material, such as ceramics, inorganic composites, and organic polymers. While ceramics possess excellent voltage resistance and stability, they also exhibit inherent characteristics such as brittleness and ease of machining irregularly shaped parts, significantly hindering the development of low-temperature plasma technology. Although inorganic composites and organic polymers offer good voltage resistance and ease of processing, their structure is disrupted under the influence of high-energy plasma. The surface stability of these materials gradually deteriorates with increasing usage time, developing strong hydrophilicity, which greatly affects the stability of the plasma discharge. This reduces the lifespan of the insulating dielectric and increases the operating cost of the plasma equipment.

[0004] Therefore, it is imperative to improve the performance of inorganic composite materials and organic polymer insulating materials, and to develop insulating dielectric substrates resistant to plasma etching. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a plasma-etchable insulating dielectric substrate.

[0006] To solve the above-mentioned technical problems, the objective of this invention is achieved through the following technical solution: providing a method for preparing a plasma-etchable insulating dielectric substrate, characterized by comprising the following steps:

[0007] S1. Grinding insulating dielectric plates and preparing thin film materials;

[0008] S2. Spray a thin film material onto the insulating dielectric board;

[0009] S3. Heat treatment to obtain the finished product.

[0010] Preferably, in step S1, the insulating dielectric plate is polished on both sides.

[0011] Preferably, in step S1, the insulating dielectric plate is ground using an abrasive, which includes high-hardness ceramic powder, a chemical dispersant, and deionized water.

[0012] Preferably, the ratio of the high-hardness ceramic powder, the chemical dispersant, and the deionized water is (0.3-0.6):(0.1-0.2):(0.5-0.9), and the particle size of the high-hardness ceramic powder is 1-10 micrometers.

[0013] Preferably, in step S1, the thin film material includes a substrate and a reinforcing body, wherein the substrate is sprayed onto an insulating dielectric plate and the reinforcing body is sprayed onto the substrate.

[0014] Preferably, the substrate is nano-alumina sol, and the film thickness of the substrate is 0.1-0.5 mm.

[0015] Preferably, the reinforcing agent is polytetrafluoroethylene filled with Al2O3, and the film thickness of the reinforcing agent is 0.1-0.5 mm.

[0016] Preferably, the method for preparing the reinforcing body is as follows:

[0017] A1. Surface modification of Al2O3 using silane coupling agents;

[0018] A2. The precipitate was obtained by filtration, washed with toluene and dried to obtain modified Al2O3.

[0019] A3. The modified Al2O3 was added to the concentrated aqueous dispersion of polytetrafluoroethylene and stirred to obtain the reinforcement.

[0020] Preferably, the weight ratio of the modified Al2O3 to polytetrafluoroethylene is (60-80):(20-40).

[0021] The roughening treatment of the insulating dielectric board surface in this invention enables the aluminum sol matrix layer to adhere efficiently to the dielectric board surface. Furthermore, the direct spraying of the reinforcing Al₂O₃-PTFE (polytetrafluoroethylene) dispersion before the aluminum sol matrix layer is completely dry not only allows for efficient adhesion of the reinforcing agent to the substrate surface, but also utilizes Al₂O₃ powder with varying particle sizes from 1 to 10 micrometers. When sprayed onto the substrate surface, this creates a uniform surface structure, somewhat uneven and resembling the surface of a lotus leaf. Simultaneously, the addition of polytetrafluoroethylene forms a highly hydrophobic layer on the dielectric board surface, ensuring extremely stable discharge processes and preventing interference from water vapor in the air. In addition, aluminum sol is used as the matrix material and Al2O3 powder is used as the filler in the reinforcing material PTFE because both are alumina ceramic materials. Alumina has a high bond energy, and high-energy particles in plasma cannot break its chemical bonds. Therefore, alumina has good resistance to plasma etching and high voltage resistance, which can more effectively protect the insulating dielectric material from plasma etching and high voltage breakdown. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Flowchart provided for embodiments of the present invention Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0028] Furthermore, terms like "roughly" and "basically" are used to indicate that the content does not require absolute precision, but rather allows for a certain degree of deviation. For example, "roughly equal" does not simply mean absolute equality; in actual production and operation, achieving absolute "equality" is difficult, and a certain degree of deviation is generally present. Therefore, besides absolute equality, "roughly equal to" also includes the aforementioned situation where a certain degree of deviation exists. Using this as an example, in other cases, unless otherwise specified, terms like "roughly" and "basically" have similar meanings.

[0029] Reference Figure 1 This invention provides a plasma-etch-resistant insulating dielectric substrate and its preparation method, the specific method of which is as follows:

[0030] 1. Surface roughening treatment of insulating dielectric board (both sides A and B):

[0031] (1) Fix the insulating dielectric plate: Fix the insulating dielectric plate on the grinding equipment, with the surface of the insulating dielectric plate in close contact with the surface of the conveyor belt of the equipment; grind surface A first, then grind surface B, with surfaces A and B being the two opposite surfaces of the insulating dielectric plate.

[0032] (2) Preparation of grinding abrasive: The abrasive is in the form of slurry, which is made by uniformly mixing high-hardness ceramic powder, chemical dispersant and deionized water. The mixing mass ratio is ceramic powder: dispersant: deionized water = (0.3-0.6): (0.1-0.2): (0.5-0.9). The high-hardness ceramic powder can be made of materials such as alumina, zirconium oxide, and silicon carbide, and the particle size is 1-20 micrometers. Then the abrasive is injected into the barrel of the grinding equipment.

[0033] (3) Grinding the insulating dielectric plate: Start the equipment, keep the insulating dielectric plate stationary, and grind the insulating dielectric plate that is in close contact with the surface of the conveyor belt by loading abrasive. The abrasive is directly fed into one end of the conveyor belt by the material cylinder through the air pump, and is collected back into the material cylinder from the other end of the conveyor belt. The grinding time is 3-10 minutes.

[0034] (4) Cleaning of insulating dielectric board: First wash off the surface abrasive with deionized water, then clean with anhydrous ethanol 1-2 times.

[0035] 2. Add an etching-resistant superhydrophobic film to the surface of the insulating dielectric substrate.

[0036] (1) Thin film material preparation: The thin film material has a two-layer structure, with the bottom layer being the matrix material and the top layer being the reinforcing material. The thickness of the thin film is 0.2-1 mm.

[0037] A. Thin Film Substrate Material: The substrate material uses nano-alumina sol. The preparation technology of alumina sol is mature. Alumina sol with a pH of 4-5 is selected from the market as the substrate material. Alumina sol has the characteristics of good stability and good adhesion. At the same time, nano-alumina has good insulation and resistance to plasma etching. The film thickness of the substrate material is 0.1-0.5 mm.

[0038] B. Reinforcing material: The reinforcing material is Al2O3-filled reinforced polytetrafluoroethylene (Al2O3-PTFE).

[0039] The film thickness of the reinforcement is 0.1-0.5 mm.

[0040] The particle size of Al2O3 is 1-10 micrometers.

[0041] Al2O3 was surface modified using a silane coupling agent, KH570. Anhydrous ethanol was added to Al2O3 to prepare a suspension. The suspension was heated in a 40°C water bath with stirring for 50 minutes. During the suspension, 300-400 mL of the silane coupling agent was added to carry out a hydrolysis reaction. After the reaction was completed, the precipitate was obtained by filtration. The precipitate was washed once with toluene and dried at 60°C to obtain modified KH570-Al2O3.

[0042] Modified KH570-Al2O3 is added to a concentrated aqueous dispersion of polytetrafluoroethylene with a solid content of 40-60%, and stirred at room temperature for 30-60 minutes to obtain a slurry of reinforcing material. The weight ratio of modified Al2O3 to polytetrafluoroethylene is (60-80):(20-40).

[0043] Al2O3 modified with silane coupling agent can effectively bind tightly to polytetrafluoroethylene (PTFE) and can be uniformly dispersed in PTFE.

[0044] (2) Thin film preparation

[0045] The thin film is prepared using ultrasonic spraying. First, an aluminum sol matrix material is poured into an ultrasonic spraying device and uniformly sprayed onto the roughened surface of the insulating dielectric substrate. The number of spraying cycles depends on the film thickness. Electrostatic spraying, ultrasonic spraying, or conventional spraying can be used. Second, after 1-5 minutes of substrate material spraying, it exhibits high adhesion, effectively adhering the reinforcing material to the surface. Then, the reinforcing Al2O3-PTFE dispersion is sprayed onto the substrate surface in the same manner, with the number of spraying cycles depending on the film thickness. Finally, the sprayed insulating dielectric substrate is placed in an oven and heat-treated at 80-160℃ for 50-80 minutes to obtain an insulating dielectric substrate material with an etch-resistant superhydrophobic film on its surface.

[0046] Specifically, when the proportion of ceramic powder is higher than 0.6 or the particle size is greater than 20 micrometers, it will damage the structure of the composite insulating dielectric plate. When the proportion of ceramic powder is lower than 0.3, the grinding effect on the insulating dielectric plate is poor, the substrate film cannot effectively adhere to the dielectric plate surface, and the film layer separates from the dielectric plate after film formation. Furthermore, during the grinding process, if the grinding time is less than 3 minutes, the grinding effect on the surface of the insulating dielectric plate is poor, the substrate coating cannot effectively adhere to the dielectric plate surface, and peeling occurs after film formation. If the grinding time is higher than 10 minutes, it will damage the structure of the insulating dielectric plate.

[0047] During cleaning, only anhydrous ethanol should be used; using other organic solvents may damage the structure of the composite material. During stirring, to ensure a more complete hydrolysis reaction of the coupling agent, the temperature and stirring time must be carefully controlled.

[0048] In addition, regarding the solid content of the concentrated polytetrafluoroethylene (PTFE) aqueous dispersion: when it is below 40%, after film formation and aging tests (25℃, 60% humidity, 8KV voltage, 100 hours), the capacitance change rate is 15.8%, the water absorption change rate is 30%, indicating poor hydrophobicity; when it is above 60%, KH570-Al2O3 and PTFE are difficult to bond tightly, and the surface of the film cannot form a "lotus leaf structure." After aging tests (25℃, 60% humidity, 8KV voltage, 100 hours), the capacitance change rate is 18.3%, the water absorption change rate is 27%, indicating poor hydrophobicity. The weight ratio of modified Al2O3 to PTFE is (60-80):(20-40); when modified Al2O3 is greater than 80%wt and PTFE is less than 20%wt, cracks appear on the film surface after heat treatment. When the modified Al2O3 content is less than 60%wt and the PTFE content is greater than 40%wt, the breakdown voltage and aging tests were performed after film formation. The overall breakdown voltage was 12KV. After testing at 25℃, 60% humidity, 8KV voltage, and 100 hours, the capacitance change rate was 16%, the water absorption rate change rate was 12%, and the etching resistance was poor.

[0049] Furthermore, the temperature and processing time requirements must be met during thin film preparation. If the temperature and time are below the requirements, the film formation effect will be poor, and the film may separate from the dielectric substrate. If the temperature and time are above the requirements, the film structure may be damaged.

[0050] It should be clarified that when the matrix thickness is less than 0.1 mm, the reinforcement will not be able to adhere strongly to the matrix surface; when it is greater than 0.5 mm, the overall thickness increases, affecting the discharge effect; when the reinforcement thickness is less than 0.1 mm, the breakdown voltage decreases significantly; when it is greater than 0.5 mm, the overall thickness increases, affecting the discharge effect.

[0051] The following are specific embodiments of the present invention:

[0052] Four materials were used for comparison: A) mica-based insulating dielectric board; B) mica-based insulating dielectric board with a single layer of aluminum sol sprayed on the surface; C) mica-based insulating dielectric board with a single layer of polytetrafluoroethylene sprayed on the surface; and D) mica-based insulating dielectric board + the method and materials of this invention. All four insulating dielectrics (A, B, C, and D) used mica insulating dielectric boards as experimental materials, and dielectric barrier discharge structure samples were fabricated accordingly. The thickness of all four films was 0.8 mm. The following tests were performed:

[0053] 1. Initial capacitance test: Test the capacitance value of the dielectric barrier discharge structure sample made of the material under the same room temperature and humidity, and observe whether the capacitance distribution is uniform.

[0054] II. Breakdown Voltage Test: The above sample was connected to a high-voltage power supply, and its breakdown voltage was measured after the discharge voltage gradually increased.

[0055] III. Aging Test: After measuring the capacitance and water absorption rate of the insulating medium surface in an environment of 25℃ and 60% humidity, the above samples were continuously operated at 8KV voltage for 100 hours, and then the capacitance and water absorption rate of the insulating medium were measured under the same environmental conditions.

[0056] IV. Record the stability of the discharge voltage during the aging test.

[0057] The test data is shown in the table below:

[0058] I. Initial capacitance test: temperature 25℃, humidity 45%.

[0059]

[0060] The data shows that the discharge structure capacitance distribution of the insulating dielectric material using the method and materials of this invention is extremely uniform, which can effectively ensure the stability of the product in use.

[0061] II. Breakdown voltage test: Temperature 25℃, humidity 45%.

[0062] sample A-4 B-4 C-4 D-4 Breakdown voltage / KV 9.35 10.56 9.89 15.21

[0063] The data shows that the breakdown voltage of the insulating dielectric material using the method and material of this invention can reach up to 15KV, which is about 62.7% higher than that of the original material A.

[0064] III. Aging test: Test temperature 25℃, test humidity 60%, test voltage 8KV, test duration 100 hours.

[0065]

[0066] The data shows that the capacitance of the insulating dielectric material using the method and material of this invention increases by only 4.2% and the water absorption rate increases by only 6.4% after aging for 100 hours, which are 87.5% and 95.5% lower than the original material, respectively.

[0067] IV. Record the stability of the discharge voltage during the aging test.

[0068]

[0069] The data shows that the discharge structure of the insulating dielectric material using the method and material of this invention has a very stable output voltage of 8±0.2KV and fewer than 10 power frequency adjustments during the test, while other materials are unstable and have more power frequency adjustments.

[0070] In summary, the method and materials described in this invention have a significant effect on improving the various properties of dielectric substrates made of inorganic composite materials and organic polymers. Specifically, the variance of capacitance values ​​is reduced when dielectric substrates from the same batch and different samples are assembled into a dielectric barrier discharge plasma device; the breakdown voltage is significantly increased compared to uncoated dielectric substrates; and the capacitance increase of the discharge device caused by moisture during the aging process is suppressed, and the matching with the plasma power supply is more stable.

[0071] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a plasma-etchable insulating dielectric substrate, characterized in that, Includes the following steps: S1. Grinding insulating dielectric plates and preparing thin film materials; S2. Spray a thin film material onto the insulating dielectric board; S3. Heat treatment to obtain the finished product; In step S1, the insulating dielectric plate is ground with an abrasive, which includes high-hardness ceramic powder, chemical dispersant and deionized water. In step S2, the thin film material includes a substrate and a reinforcement. The substrate is sprayed onto an insulating dielectric plate, and the reinforcement is sprayed onto the substrate. The substrate is nano-alumina sol, and the film thickness of the substrate is 0.1-0.5 mm. The reinforcement is polytetrafluoroethylene filled with Al2O3, and the film thickness of the reinforcement is 0.1-0.5 mm.

2. The method for preparing the plasma-etch-resistant insulating dielectric substrate according to claim 1, characterized in that: In step S1, the insulating dielectric plate is ground on both sides.

3. The method for preparing a plasma-etch-resistant insulating dielectric substrate according to claim 1, characterized in that, The method for preparing the reinforcing material is as follows: A1. Surface modification of Al2O3 using silane coupling agents; A2. The precipitate was obtained by filtration, washed with toluene and dried to obtain modified Al2O3. A3. The modified Al2O3 was added to the concentrated aqueous dispersion of polytetrafluoroethylene and stirred to obtain the reinforcement.

4. The method for preparing a plasma-etch-resistant insulating dielectric substrate according to claim 3, characterized in that: The weight ratio of the modified Al2O3 to polytetrafluoroethylene is (60-80):(20-40).

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