Charge dissipation coating, preparation method thereof and ceramic product

Abstract

The invention provides a charge dissipation coating, a preparation method thereof and a ceramic product, and belongs to the technical field of ceramics. The charge dissipation coating comprises the following components: a resin matrix comprising epoxy resin and a polyurethane prepolymer; the conductive filler comprises a flaky conductive filler, an epoxy functionalized carbon nanotube and conductive carbon black; the epoxy functionalized carbon nano tube is a carbon nano tube of which the surface is grafted with glycidyl ether oxygen groups or derivative groups thereof; the dispersing and coupling system comprises a dispersing agent and at least one silane coupling agent; a curing agent; and a solvent. According to the charge dissipation coating disclosed by the invention, the components such as the epoxy resin, the polyurethane prepolymer, the flaky conductive filler, the epoxy functionalized carbon nanotubes and the conductive carbon black are reasonably compounded, and the specific silane coupling agent, the titanate coupling agent and the dispersing agent are matched; a coating with excellent charge dissipation performance (low surface resistance and short charge half-life period) and good adhesive force can be formed on the surface of a ceramic substrate.

Description

Technical Field

[0001] This application relates to the field of ceramic technology, and in particular to a charge dissipation coating, its preparation method, and ceramic products thereof. Background Technology

[0002] Ceramic materials possess advantages such as high hardness, wear resistance, and corrosion resistance, and are widely used in electronics, chemical, and medical fields. However, ceramic materials typically have high surface resistivity, making them prone to static electricity accumulation and potential discharge hazards. Current technologies for antistatic treatment of ceramics mainly employ methods such as surface metallization, doping with conductive phases, or coating with antistatic coatings. However, these methods suffer from high costs, poor adhesion, susceptibility to oxidation, and issues affecting the transparency or appearance of the ceramic. Existing antistatic coatings exhibit weak adhesion to the ceramic substrate, poor wear resistance and temperature resistance, and unstable charge dissipation performance.

[0003] Therefore, there is an urgent need to develop a coating solution that has strong adhesion to ceramic substrates and stable charge dissipation performance. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide a charge dissipation coating, a method for preparing the same, and ceramic products thereof.

[0005] Specifically, the first aspect of this application provides a charge dissipation coating comprising the following components: Resin matrix, including epoxy resin and polyurethane prepolymer; The conductive filler comprises sheet-like conductive filler, epoxy-functionalized carbon nanotubes, and conductive carbon black; wherein the epoxy-functionalized carbon nanotubes are carbon nanotubes with glycidyl ether oxygen groups or their derivative groups grafted onto their surface. A dispersion and coupling system comprising a dispersant and at least one silane coupling agent; Curing agent; And solvents.

[0006] Furthermore, the silane coupling agent is prepared by compounding an epoxy silane coupling agent and an amino silane coupling agent at a mass ratio of 1:0.3-0.8.

[0007] Furthermore, the curing agent is a phenolic amine curing agent.

[0008] Furthermore, in the conductive filler, the sheet-like conductive filler is a mica sheet with tin oxide coated on its surface.

[0009] Furthermore, the dispersion and coupling system also includes a titanate coupling agent.

[0010] A second aspect of this application provides a method for preparing a charge dissipation coating, comprising the following steps: S1: Epoxy-functionalized carbon nanotubes, dispersant and first part of solvent are mixed and first dispersion treatment is performed to obtain primary dispersion slurry; S2: Add flake conductive filler, conductive carbon black and titanate coupling agent to the primary dispersion slurry, and perform a second dispersion treatment to obtain a composite conductive slurry; S3: Mix epoxy resin, polyurethane prepolymer, silane coupling agent and the solvent in the second part to obtain a resin mixture; S4: Mix the composite conductive paste with the resin mixture; S5: Add the curing agent, mix, and then perform a controlled-moisture curing treatment to obtain the charge dissipation coating.

[0011] Furthermore, the first dispersion process is carried out under cooling conditions, with a dispersion speed of 4000-6000 rpm and a time of 20-40 minutes.

[0012] Furthermore, the relative humidity of the humidity-controlled curing treatment is 40%-60%, the temperature is 20-30℃, and the time is 24-72 hours.

[0013] A third aspect of this application provides a ceramic article, the surface of which is coated with a charge dissipation coating, the charge dissipation coating being formed by curing the charge dissipation coating on the surface of a ceramic substrate.

[0014] Furthermore, the ceramic substrate undergoes a silane pre-coupling treatment before coating; The treatment solution used for the silane pre-coupling treatment contains a silane coupling agent, water, alcohol, and a pH adjuster.

[0015] Furthermore, the method for preparing the ceramic product includes: Pre-treatment of the ceramic substrate surface; The charge dissipation coating is applied to the surface of the pretreated ceramic substrate to form a wet film. The wet film is then subjected to step curing.

[0016] Further, the stepped curing includes: First stage: Gradient temperature gelation at 40-65℃; Second stage: medium-temperature curing at 80-95℃; The third stage: high-temperature curing at 100-120℃.

[0017] Furthermore, after the third stage, the temperature is further reduced to below 60°C at a rate not exceeding 1.5°C / min.

[0018] The present invention has the following beneficial effects: This invention combines epoxy resin and polyurethane prepolymer in a resin matrix, which can leverage the synergistic effect of the two to ensure the mechanical strength and chemical corrosion resistance of the coating, while also giving the coating good flexibility. This effectively alleviates the internal stress caused by the difference in thermal expansion coefficients between the ceramic substrate and the coating, and improves the crack resistance of the coating.

[0019] The conductive filler adopts a composite system of sheet-like conductive filler, epoxy-functionalized carbon nanotubes, and conductive carbon black. The sheet-like conductive filler can form a good conductive path in the coating. The epoxy-functionalized carbon nanotubes, through the glycidyl ether oxygen groups or their derivative groups grafted on the surface, can chemically react with the epoxy resin in the resin matrix, significantly improving its dispersibility and interfacial bonding in the resin matrix. The conductive carbon black can fill the gaps between the sheet-like conductive filler and the carbon nanotubes, further optimizing the conductive network and giving the coating a stable and long-lasting charge dissipation capability.

[0020] The dispersant in the dispersion and coupling system effectively prevents the agglomeration of conductive fillers. Silane coupling agents (especially bifunctional silane coupling agents containing both epoxy and amino groups) can form chemical bonds between the resin matrix and the ceramic substrate, significantly improving the adhesion between the coating and the substrate. Adding titanate coupling agents can further enhance the compatibility between the conductive filler and the resin matrix. A phenolic amine curing agent is selected, possessing excellent low-temperature curing performance and superior resistance to damp heat. Combined with specific humidity-controlled curing treatment, it ensures complete curing of the coating, forming a uniform and dense cured network. This results in a charge-dissipating coating that not only has stable charge-dissipating performance but also excellent wear resistance, chemical corrosion resistance, and high-temperature resistance, meeting the stringent antistatic requirements of ceramic products in various application scenarios. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following description and illustration are provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0022] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0023] An embodiment of the first aspect of this application provides a charge dissipation coating comprising the following components: Resin matrix, including epoxy resin and polyurethane prepolymer; The conductive filler comprises sheet-like conductive filler, epoxy-functionalized carbon nanotubes, and conductive carbon black; wherein the epoxy-functionalized carbon nanotubes are carbon nanotubes with glycidyl ether oxygen groups or their derivative groups grafted onto their surface. A dispersion and coupling system comprising a dispersant and at least one silane coupling agent; Curing agents; and solvents.

[0024] The charge dissipation coating comprises the following components in parts by weight: 20-25 parts epoxy resin, 12-20 parts polyurethane prepolymer, 15-25 parts sheet-like conductive filler, 3-8 parts epoxy functionalized carbon nanotubes, 8-12 parts conductive carbon black, 1.5-3 parts dispersant, 1-2 parts silane coupling agent, 0.5-1 part titanate coupling agent, 6-12 parts curing agent, solvent (15-25 parts propylene glycol methyl ether acetate, 5-10 parts divalent ester mixed solvent), leveling agent (polyether modified siloxane, model: BYK-333) 0.1-0.5 parts, and fumed silica 0.3-0.5 parts.

[0025] In this embodiment, the preparation method of the epoxy-functionalized carbon nanotubes is as follows: purified carbon nanotubes are placed in a 3:1 (v / v) concentrated H2SO4 / HNO3 mixture, ultrasonically treated at 60°C for 4 hours, washed and dried to obtain carboxylated carbon nanotubes; then, the carboxylated carbon nanotubes are reacted with epichlorohydrin at 80°C for 12 hours under NaOH catalysis, and washed and dried to obtain the final product. The molar ratio of carboxylated carbon nanotubes to epichlorohydrin is 1:1.5; the molar ratio of epichlorohydrin to NaOH is 1:2.

[0026] In this embodiment, the silane coupling agent is prepared by compounding an epoxy silane coupling agent and an amino silane coupling agent at a mass ratio of 1:0.3-0.8. The epoxy silane coupling agent is γ-glycidoxypropyltrimethoxysilane (KH-560); the amino silane coupling agent is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792). The amino group of the amino silane coupling agent can catalyze the rapid curing of the epoxy resin, and the epoxy and amino groups can react to form an in-situ organosilicon crosslinked network between the ceramic matrix and the resin coating. This network acts as a stress buffer layer and chemical bridge, significantly improving adhesion and environmental aging resistance.

[0027] In this embodiment, the curing agent is a phenolic amine curing agent (T-31).

[0028] The dispersant is a polyetheramine type dispersant (BYK-2155).

[0029] In this embodiment, the conductive filler is a sheet-like conductive filler made of mica sheet coated with tin oxide (Wuhan Changfeng Mica Insulation Materials Co., Ltd.).

[0030] An embodiment of the second aspect of this application provides a method for preparing a charge dissipation coating, comprising the following steps: S1: Epoxy-functionalized carbon nanotubes, dispersant and first part of solvent are mixed and first dispersion treatment is performed to obtain primary dispersion slurry; S2: Add flake conductive filler, conductive carbon black and titanate coupling agent to the primary dispersion slurry, and perform a second dispersion treatment to obtain a composite conductive slurry; S3: Mix epoxy resin, polyurethane prepolymer, silane coupling agent and the solvent in the second part to obtain a resin mixture; S4: Mix the composite conductive paste with the resin mixture; S5: Add the curing agent, mix, and then perform a controlled-moisture curing treatment to obtain the charge dissipation coating.

[0031] Further, in step S1, dry epoxy-functionalized carbon nanotubes, dispersant and the first part of solvent (half the amount of propylene glycol methyl ether acetate) are added to the dispersion vessel. The cooling system is turned on to keep the material temperature below 10°C. The disperser is started and high-speed shear dispersion is performed at a speed of 4000-6000 rpm for 20-40 minutes to obtain the primary dispersion slurry.

[0032] While maintaining stirring (speed reduced to 2000 rpm), add flake conductive filler and titanate coupling agent to the primary dispersion slurry, maintain dispersion at 2000 rpm for 20 minutes to fully wet and coat the mica flakes, then add conductive carbon black and half the amount of propylene glycol methyl ether acetate, adjust the speed to 1500 rpm, and continue dispersion for 15 minutes to obtain a uniform, fine, black slurry without visible particles; Step S3: Add epoxy resin, polyurethane prepolymer, silane coupling agent and divalent ester mixed solvent to the reactor, purge with nitrogen to replace air, maintain a slight positive pressure, turn on the stirrer (anchor blade, speed 250 rpm) and heat, so that the material temperature rises uniformly to 45-55℃, and stir at this temperature for 40 minutes to partially hydrolyze the silane and distribute it evenly in the resin to obtain a resin mixture. Step S4: Slowly pour the composite conductive slurry into the resin mixture while stirring the reactor at 300 rpm for 40 minutes. Slowly add the curing agent and continue stirring at 400 rpm for 20 minutes to ensure uniform mixing. Then add the leveling agent BYK-333 and fumed silica, and disperse at 800 rpm for 10 minutes. Transfer the resulting coating to a humidity-controlled, sealed curing tank; adjust the relative humidity to 40%-60%, the temperature to 20-30℃, and the treatment time to 24-72 hours.

[0033] An embodiment of the third aspect of this application provides a ceramic article, the surface of which is coated with a charge dissipation coating, the charge dissipation coating being formed by curing the charge dissipation coating on the surface of a ceramic substrate.

[0034] In this embodiment, the ceramic substrate undergoes silane pre-coupling treatment before coating; specifically, 1g of silane coupling agent is added to a mixture of 5g deionized water and 95g anhydrous ethanol, the pH is adjusted to 5.0-5.5 with glacial acetic acid, and the mixture is stirred and hydrolyzed for 30 minutes at room temperature; the cleaned and dried ceramic blank is completely immersed in the pretreatment solution for 2 minutes; it is then lifted out at a uniform speed of 10cm / min, and excess liquid is drained; it is immediately placed in a preheated oven at 120℃ for heat treatment for 10 minutes.

[0035] In this embodiment, the method for preparing the ceramic product includes: Pre-treatment of the ceramic substrate surface; Load the cured coating into the spray gun (nozzle diameter: 1.3mm), and adjust the spraying parameters as follows: air pressure 0.4-0.5MPa, spray gun distance from the substrate 20-25 cm, moving speed 0.5 m / s; use the cross-spraying method, spraying back and forth twice to ensure that the wet film thickness is uniform and reaches 75μm; The wet film is cured in a stepwise manner: First stage: Gradual heating gelation is carried out at 40-65℃, and the temperature is maintained for 20 minutes; Second stage: medium-temperature curing at 80-95℃ for 90 minutes; The third stage: high-temperature curing at 100-120℃ for 150 minutes; then cooling down to below 60℃ at a rate not exceeding 1.5℃ / min.

[0036] Example The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight. Unless otherwise stated, all reagents used in the examples are available commercially or synthesized using conventional methods and are ready for use without further processing. Unless otherwise stated, all instruments used in the examples are available commercially.

[0037] Example 1 A charge dissipation coating comprises, by weight, the following components: 23 parts epoxy resin (E-51), 16 parts polyurethane prepolymer, 21 parts sheet-like conductive filler, 5 parts epoxy functionalized carbon nanotubes, 10 parts conductive carbon black, 2 parts polyether amine dispersant (BYK-2155), 1 part γ-glycidyl etheroxypropyltrimethoxysilane (KH-560), 0.5 parts N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), 0.8 parts titanate coupling agent (LICA-38), 9 parts phenolic amine curing agent (T-31), 20 parts propylene glycol methyl ether acetate, 8 parts divalent ester mixed solvent (DBE), 0.3 parts polyether modified siloxane (model BYK-333), and 0.4 parts fumed silica.

[0038] The preparation method of the epoxy-functionalized carbon nanotubes is as follows: purified carbon nanotubes are placed in a 3:1 (v / v) concentrated H2SO4 / HNO3 mixture, ultrasonically treated at 60°C for 4 hours, washed and dried to obtain carboxylated carbon nanotubes; then, the carboxylated carbon nanotubes are reacted with epichlorohydrin at 80°C for 12 hours under NaOH catalysis, and washed and dried to obtain the final product. The molar ratio of carboxylated carbon nanotubes to epichlorohydrin is 1:1.5; the molar ratio of epichlorohydrin to NaOH is 1:2. The polyurethane prepolymer was purchased from Jiangsu Qianmeite Polyurethane New Materials Co., Ltd. The sheet-like conductive filler is a mica sheet coated with tin oxide, purchased from Wuhan Changfeng Mica Insulation Materials Co., Ltd. A method for preparing a charge dissipation coating includes the following steps: S1: Mix epoxy-functionalized carbon nanotubes, dispersant and half the amount of propylene glycol methyl ether acetate, turn on the cooling system to keep the material temperature below 10°C, start the disperser and shear disperse at 5000 rpm for 30 minutes to obtain the primary dispersion slurry. S2: Add sheet-like conductive filler and titanate coupling agent to the primary dispersion slurry, maintain dispersion at 2000 rpm for 20 minutes, then add conductive carbon black and half of propylene glycol methyl ether acetate, adjust the speed to 1500 rpm, and continue dispersion for 15 minutes to obtain composite conductive slurry; S3: Mix epoxy resin, polyurethane prepolymer, silane coupling agent and divalent ester solvent, purge with nitrogen to replace air, maintain a slight positive pressure, turn on stirring (anchor blade, speed 250 rpm) and heating, so that the material temperature rises uniformly to 50℃, and stir at this temperature for 40 minutes to obtain resin mixture. S4: Slowly pour the composite conductive paste into the resin mixture while stirring the reactor at 300 rpm for 40 minutes. S5: Add the curing agent and continue stirring at 400 rpm for 20 minutes to ensure uniform mixing. Then add the leveling agent BYK-333 and fumed silica, and disperse at 800 rpm for 10 minutes. Transfer the resulting coating to a humidity-controlled, sealed curing tank; adjust the relative humidity to 50%, the temperature to 25°C, and the treatment time to 48 hours to obtain the charge dissipation coating.

[0039] Example 2 A charge dissipation coating comprises the following components in parts by weight: 25 parts epoxy resin (E-51), 15 parts polyurethane prepolymer, 20 parts sheet-like conductive filler, 3 parts epoxy functionalized carbon nanotubes, 10 parts conductive carbon black, 2 parts polyether amine dispersant (BYK-2155), 1 part γ-glycidyl etheroxypropyltrimethoxysilane (KH-560), 0.5 parts N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), 0.8 parts titanate coupling agent (LICA-38), 9 parts phenolic amine curing agent (T-31), 20 parts propylene glycol methyl ether acetate, 8 parts divalent ester mixed solvent (DBE), 0.3 parts polyether modified siloxane (model BYK-333), and 0.4 parts fumed silica.

[0040] The preparation method of the charge dissipation coating is the same as in Example 1.

[0041] Example 3 A charge dissipation coating comprises the following components in parts by weight: 21 parts epoxy resin (E-51), 19 parts polyurethane prepolymer, 20 parts sheet-like conductive filler, 7 parts epoxy functionalized carbon nanotubes, 10 parts conductive carbon black, 2 parts polyether amine dispersant (BYK-2155), 1 part γ-glycidyl etheroxypropyltrimethoxysilane (KH-560), 0.5 parts N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), 0.8 parts titanate coupling agent (LICA-38), 9 parts phenolic amine curing agent (T-31), 20 parts propylene glycol methyl ether acetate, 8 parts divalent ester mixed solvent (DBE), 0.3 parts polyether modified siloxane (model BYK-333), and 0.4 parts fumed silica.

[0042] The preparation method of the charge dissipation coating is the same as in Example 1.

[0043] Example 4 A charge dissipation coating comprises the following components in parts by weight: 23 parts epoxy resin (E-51), 17 parts polyurethane prepolymer, 25 parts sheet-like conductive filler, 5 parts epoxy functionalized carbon nanotubes, 10 parts conductive carbon black, 2 parts polyether amine dispersant (BYK-2155), 1 part γ-glycidyl etheroxypropyltrimethoxysilane (KH-560), 0.5 parts N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), 0.8 parts titanate coupling agent (LICA-38), 9 parts phenolic amine curing agent (T-31), 20 parts propylene glycol methyl ether acetate, 8 parts divalent ester mixed solvent (DBE), 0.3 parts polyether modified siloxane (model BYK-333), and 0.4 parts fumed silica.

[0044] The preparation method of the charge dissipation coating is the same as in Example 1.

[0045] Example 5 A charge dissipation coating comprises the following components in parts by weight: 23 parts epoxy resin (E-51), 17 parts polyurethane prepolymer, 15 parts sheet-like conductive filler, 5 parts epoxy functionalized carbon nanotubes, 10 parts conductive carbon black, 2 parts polyether amine dispersant (BYK-2155), 1 part γ-glycidyl etheroxypropyltrimethoxysilane (KH-560), 0.5 parts N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), 0.8 parts titanate coupling agent (LICA-38), 9 parts phenolic amine curing agent (T-31), 20 parts propylene glycol methyl ether acetate, 8 parts divalent ester mixed solvent (DBE), 0.3 parts polyether modified siloxane (model BYK-333), and 0.4 parts fumed silica.

[0046] The preparation method of the charge dissipation coating is the same as in Example 1.

[0047] Comparative Example 1 This comparative example is basically the same as Example 1, except that ordinary mica sheets are used instead of mica sheets with tin oxide coating on the surface.

[0048] Comparative Example 2 This comparative example is basically the same as Example 1, except that the silane coupling agent contains only γ-glycidoxypropyltrimethoxysilane (KH-560) and does not contain N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792).

[0049] Comparative Example 3 This comparative example is basically the same as Example 1, except that it does not contain titanate coupling agent.

[0050] Comparative Example 4 This comparative example is basically the same as Example 1, except that it does not contain a dispersant.

[0051] Experimental Case The charge dissipation coatings prepared in Examples 1-5 and Comparative Examples 1-4 were respectively coated on the surfaces of different ceramic substrates. The specific operation methods are as follows: 1) Pretreatment of ceramic substrate surface: Add 1g of silane coupling agent to a mixture of 5g deionized water and 95g anhydrous ethanol, adjust the pH to 5.0 with glacial acetic acid, and stir and hydrolyze for 30 minutes at room temperature; completely immerse the cleaned and dried ceramic body in the pretreatment solution for 2 minutes; lift it out at a uniform speed of 10 cm / min, drain excess liquid; immediately place it in a preheated oven at 120℃ and heat treat for 10 minutes. 2) Spraying: Load the cured charge dissipation into the spray gun (nozzle diameter: 1.3mm), adjust the spraying parameters: air pressure 0.45 MPa, spray gun distance from the substrate 20-25 cm, moving speed 0.5 m / s; use cross spraying method, spray back and forth 2 times to ensure that the wet film thickness is uniform and reaches 75μm; 3) Stepwise curing of the wet film: First stage: Gradual heating gel at 40-65℃, holding for 20 minutes; Second stage: Medium temperature curing at 80-95℃ for 90 minutes; Third stage: High temperature curing at 100-120℃ for 150 minutes; Then cooling down to below 60℃ at a rate not exceeding 1.5℃ / min.

[0052] The following performance tests were performed on the cured coating: Surface resistivity: According to ASTM D257, it was tested using a Keithley 6517B high resistance meter at (23±2)°C and 50%RH, and the average value of 5 points was taken.

[0053] Charge half-life: Tested according to GB / T 26539 using an electrostatic decay tester (Electro-Tech Systems 406D).

[0054] Adhesion: According to GB / T 9286 (cross-cut test), using a 1mm spacing cross-cut tester, 3M tape is applied and then quickly peeled off, rating (0 is the best, 5 is the worst).

[0055] The test results are shown in Table 1.

[0056] Table 1. Performance test results of charge dissipation coatings in Examples 1-5 and Comparative Examples 1-4

[0057] As shown in Table 1, Example 1 is the optimal solution. In Example 2, the amount of epoxy-functionalized carbon nanotubes used is 3 parts, which is lower than the 5 parts used in Example 1, resulting in an increase in surface resistivity to 8.5 × 10⁻⁶. 7 Ω / sq, the charge half-life is extended to 1.5s, but it is still within the ideal range for charge dissipation materials (surface resistivity 10 Ω / sq). 6 -10 9 Ω / sq, charge half-life <2s), and adhesion remained at level 0; Example 3 increased the amount of epoxy-functionalized carbon nanotubes to 7 parts, further reducing the surface resistivity to 9.0 × 10 Ω / sq, charge half-life <2s), and adhesion remained at level 0; 6 The surface resistivity is Ω / sq, the charge half-life is shortened to 0.5s, and the conductivity is even better; Example 4 increased the amount of sheet-like conductive filler to 25 parts, and the surface resistivity was 1.1×10 Ω / sq. 7 With a charge half-life of 0.6 s and Ω / sq, it also exhibits good charge dissipation performance; Example 5 reduced the amount of sheet-like conductive filler to 15 parts, resulting in a significant increase in surface resistivity to 7.0 × 10 Ω / sq. 8 The charge half-life is extended to 2.8s, which still meets the basic requirements for charge dissipation, but the performance is lower than that of Example 1.

[0058] Comparative Example 1 uses ordinary mica sheets instead of mica sheets coated with tin oxide, and its surface resistivity is 5.0 × 10⁻⁶. 7 The surface resistance is slightly higher and the charge decay rate is slightly slower than that of Example 1. This may be because ordinary mica sheets do not have conductivity and cannot provide an effective conductive path like mica sheets with tin oxide coating. As a result, the overall conductive network of the coating is not well constructed and the charge conduction efficiency is reduced.

[0059] Comparative Example 2 used only γ-glycidoxypropyltrimethoxysilane (KH-560) as a silane coupling agent, without N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), and its adhesion dropped to grade 1. This is because KH-560 mainly reacts with epoxy groups in the resin matrix, while KH-792 contains amino groups, which can form stronger chemical bonds with hydroxyl groups and other groups on the surface of the resin and substrate. The synergistic effect of the two coupling agents can significantly improve the interfacial bonding between the coating and the substrate. Without KH-792, the interfacial bonding strength decreased, resulting in a lower adhesion rating.

[0060] Comparative Example 3, which does not contain titanate coupling agent, also shows a drop in adhesion to grade 1 and a charge half-life extended to 1.8 s. This may be because titanate coupling agent can effectively improve the compatibility and interfacial bonding between inorganic fillers such as flake conductive fillers and conductive carbon black and the organic resin matrix, and promote the uniform dispersion of fillers in the matrix. Without it, the filler dispersion deteriorates, which not only affects the mechanical properties of the coating and leads to a decrease in adhesion, but also affects the continuity of the conductive path and slows down the charge decay rate.

[0061] Comparative Example 4, which contains no dispersant, exhibits a significantly increased surface resistivity of 2.1 × 10⁻⁶. 9 With a charge half-life exceeding 10s and an adhesion level dropping to 2, the dispersant (BYK-2155) significantly reduces the agglomeration force between solid particles, helping nanoscale and microscale conductive fillers such as epoxy functionalized carbon nanotubes and conductive carbon black to achieve stable and uniform dispersion in solvent and resin systems. Without the dispersant, conductive fillers are prone to agglomeration, forming large aggregates that cannot construct an effective three-dimensional conductive network in the coating, resulting in the inability to dissipate charges quickly. At the same time, the agglomerated fillers also cause stress concentration inside the coating, severely affecting the bonding force between the coating and the substrate, resulting in a significant decrease in adhesion.

[0062] In summary, the charge dissipation coating provided in this application, through the rational compounding of epoxy resin, polyurethane prepolymer, sheet-like conductive filler, epoxy functionalized carbon nanotubes, conductive carbon black and other components, and in conjunction with specific silane coupling agents, titanate coupling agents and dispersants, can form a coating with excellent charge dissipation performance (low surface resistance, short charge half-life) and good adhesion on the surface of ceramic substrates.

[0063] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A charge dissipation coating, characterized in that, It contains the following components: Resin matrix, including epoxy resin and polyurethane prepolymer; The conductive filler comprises sheet-like conductive filler, epoxy-functionalized carbon nanotubes, and conductive carbon black; wherein the epoxy-functionalized carbon nanotubes are carbon nanotubes with glycidyl ether oxygen groups or their derivative groups grafted onto their surface. A dispersion and coupling system comprising a dispersant and at least one silane coupling agent; Curing agent; And solvents.

2. The charge dissipation coating according to claim 1, characterized in that, The silane coupling agent is prepared by compounding an epoxy silane coupling agent and an amino silane coupling agent at a mass ratio of 1:0.3-0.8; And / or, the curing agent is a phenolic amine curing agent.

3. The charge dissipation coating according to claim 1, characterized in that, In the conductive filler, the sheet-like conductive filler is a mica sheet with tin oxide coated on its surface.

4. The charge dissipation coating according to claim 1, characterized in that, The dispersion and coupling system also includes a titanate coupling agent.

5. A method for preparing a charge dissipation coating, characterized in that, The preparation of the charge dissipation coating according to any one of claims 1-4 includes the following steps: S1: Epoxy-functionalized carbon nanotubes, dispersant and first part of solvent are mixed and first dispersion treatment is performed to obtain primary dispersion slurry; S2: Add flake conductive filler, conductive carbon black and titanate coupling agent to the primary dispersion slurry, and perform a second dispersion treatment to obtain a composite conductive slurry; S3: Mix epoxy resin, polyurethane prepolymer, silane coupling agent and the solvent in the second part to obtain a resin mixture; S4: Mix the composite conductive paste with the resin mixture; S5: Add the curing agent, mix, and then perform a controlled-moisture curing treatment to obtain the charge dissipation coating.

6. The method for preparing the charge dissipation coating according to claim 5, characterized in that, In step S1, the first dispersion process is carried out under cooling conditions, with a dispersion speed of 4000-6000 rpm and a time of 20-40 minutes.

7. The method for preparing the charge dissipation coating according to claim 5, characterized in that, In step S5, the relative humidity of the humidity-controlled curing treatment environment is 40%-60%, the temperature is 20-30℃, and the time is 24-72 hours.

8. A ceramic product, characterized in that, The ceramic product is coated with a charge dissipation coating, which is formed by curing the charge dissipation coating as described in any one of claims 1-4 onto the surface of the ceramic substrate.

9. The ceramic article according to claim 8, characterized in that, The ceramic substrate undergoes silane pre-coupling treatment before coating; The treatment solution used for the silane pre-coupling treatment contains a silane coupling agent, water, alcohol, and a pH adjuster.

10. The ceramic article according to claim 8, characterized in that, The method for preparing the ceramic product includes: Pre-treatment of the ceramic substrate surface; The charge dissipation coating according to any one of claims 1 to 4 is applied to the surface of a pretreated ceramic substrate to form a wet film; The wet film is then subjected to step curing.

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