An antistatic environmentally friendly solvent-free coating and its preparation method

Abstract

The present invention relates to the technical field of environmentally friendly solvent-free coatings, and specifically to an antistatic environmentally friendly solvent-free coating and a preparation method thereof, which are composed of the following components in mass percentages: 30-45% of polyurethane acrylate oligomer, 15-25% of organosilicon-modified acrylate resin, 3-8% of ionic liquid antistatic agent, 0.5-2.5% of carbon nanotube conductive filler, 0.3-1.2% of nano-silica, 2-5% of dispersant, 0.1-0.8% of leveling agent, 0.05-0.3% of defoaming agent, and the balance is active diluent. In the present invention, through the synergistic effect of the ionic liquid antistatic agent and the carbon nanotube conductive filler, the volume resistance of the coating is ensured, and the stable antistatic ability of the coating surface is ensured. The present invention adopts the surface modification technology of carbon nanotubes, and uses silane coupling agent to functionalize the carbon nanotubes, so that they can be evenly dispersed in the coating system to form a stable conductive network structure, thereby improving the conductivity uniformity and long-term antistatic effect of the coating.

Description

Technical Field

[0001] The present invention relates to the technical field of environmentally friendly solvent-free coatings, and specifically to an antistatic environmentally friendly solvent-free coating and a preparation method thereof. Background Art

[0002] Antistatic coatings are a special functional coating material, widely used in industries such as electronic manufacturing, precision instruments, medical equipment, aerospace, semiconductor production, explosion-proof places, etc. It is mainly used to prevent the accumulation of static electricity and reduce the potential safety hazards caused by electrostatic discharge (ESD). For example, in the electronic manufacturing industry, static electricity may damage integrated circuit chips and affect the stable operation of precision instruments; in the medical field, static electricity may cause dust adsorption and affect the cleanliness of the dust-free environment; in the chemical and energy industries, the accumulation of static electricity may even cause spark discharge and lead to explosion accidents. Therefore, antistatic coatings with stable antistatic ability, high mechanical strength, and environmental protection and pollution-free have become an important research direction in this field.

[0003] At present, the antistatic coatings on the market mainly improve the antistatic performance of the coating by means of conductive filler modification, ionic antistatic agents, and copolymer modification. However, the traditional methods have the problems that the ionic antistatic agents are easy to migrate and lose, and the conductive fillers are easy to agglomerate or settle, resulting in the gradual decline of the antistatic performance of the coating during use and unable to meet the requirements of long-term stable use.

[0004] Therefore, we propose an antistatic environmentally friendly solvent-free coating and a preparation method thereof. Summary of the Invention

[0005] (I) Technical Problems to be Solved

[0006] The purpose of the present invention is to provide an antistatic environmentally friendly solvent-free coating and a preparation method thereof to solve the problems raised in the above background art.

[0007] (II) Technical Solutions

[0008] To achieve the above purpose, the present invention provides the following technical solutions:

[0009] An antistatic environmentally friendly solvent-free coating is composed of the following components in mass percentage: 30-45% of polyurethane acrylate oligomer, 15-25% of organosilicon-modified acrylate resin, 3-8% of ionic liquid antistatic agent, 0.5-2.5% of carbon nanotube conductive filler, 0.3-1.2% of nano-silica, 2-5% of dispersant, 0.1-0.8% of leveling agent, 0.05-0.3% of defoaming agent, and the balance is active diluent; wherein the carbon nanotube conductive filler is surface-treated with a silane coupling agent, the aspect ratio is controlled at 100-200, and the specific surface area ≥ 200m 2 / g; the ionic liquid is a compound of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-ethyl-3-methylimidazolium tetrafluoroborate in a mass ratio of 2:1; the reactive diluent is a mixture of trimethylolpropane triacrylate and dipropylene glycol diacrylate in a composition ratio of 3:2; the volume resistivity of the coating , the VOC content is < 15 g / L, and the pencil hardness of the cured film is ≥ 4H.

[0010] A preparation method of an antistatic and environmentally friendly solvent-free coating comprises the following steps:

[0011] (1) Predispersion treatment: Preheat the polyurethane acrylate oligomer and the organosilicon-modified acrylate resin at 60 - 70 °C for 30 min, add the reactive diluent preheated to 50 °C, and stir at 400 - 600 rpm to form a homogeneous base material;

[0012] (2) Gradient dispersion: Add the carbon nanotube conductive filler to the base material in three portions. After each addition, first disperse at a high speed of 1200 rpm for 10 min, and then switch to a three-roll mill for 3 passes of grinding, with the roll gap adjusted successively to 50 μm, 30 μm, and 15 μm;

[0013] (3) Antistatic system construction: Under nitrogen protection, premix the ionic liquid antistatic agent and nano-silica in a ratio of 1:0.3, heat to 80 °C at a rate of 0.5 °C / min and hold for 15 min, and then inject it into the dispersion system in a pulsed feeding manner;

[0014] (4) Functional additive integration: After the system cools down to below 45 °C, add a dispersant, a leveling agent, and a defoaming agent in sequence, and mix for 40 min using a planetary mixer in a compound motion mode of 20 rpm for revolution + 800 rpm for rotation;

[0015] (5) Viscosity regulation: Monitor the viscosity of the system through an online rheometer. When the viscosity reaches 1500 - 2000 mPa·s, start the ultrasonic-assisted defoaming device and process for 15 - 20 min;

[0016] (6) Aging treatment: Transfer the material to a constant-temperature aging tank, let it stand at 35 ± 2 °C for 24 h, and start low-speed stirring for 5 min every 4 h during this period.

[0017] As a preferred technical solution, in the step (1), the preheating adopts segmented temperature control: heat to 50 °C at a rate of 2 °C / min in the first 10 min, then heat to 65 °C at a rate of 1 °C / min and hold for 15 min, and finally heat to 70 °C at a rate of 0.5 °C / min; the stirring paddle adopts a double-layer serrated structure, the diameter ratio of the lower paddle blade to the container diameter is 0.6:1, the upper layer is 0.4:1, and the distance between the two paddles is 1 / 3 of the container height.

[0018] As a preferred technical solution, the timings for adding carbon nanotubes three times in step (2) are as follows: 50% of the total amount is added for the first time when the base material temperature reaches 60°C, 30% is added before the second pass of three-roll grinding for the second time, and 20% is added after the grinding is completed for the third time; different dispersion procedures are adopted after each addition: a dispersion disc with a diameter of Φ25 mm is used for the first time, replaced with a Φ18 mm conical disc for the second time, and a Φ30 mm flat disc is used for the third time.

[0019] As a preferred technical solution, the specific parameters of the pulsed feeding in step (3) are: feeding frequency 2 Hz, single-pulse duration 0.5 s, interval time 1.5 s, the outlet of the feeding pipe is designed as a rotatable fan-shaped nozzle, and the rotational speed is linked with the feeding pump frequency and controlled at 30 - 60 rpm; the nano-silica is pre-treated by plasma, with a treatment power of 300 W, a time of 5 min, and a mixed gas of argon and oxygen with a volume ratio of 4:1 is introduced.

[0020] As a preferred technical solution, the ratio of the revolution speed to the rotation speed of the planetary mixer in step (4) is controlled according to the time program: 1:40 for the first 10 min, adjusted to 1:60 for the middle 20 min, and reduced to 1:30 for the last 10 min; 6 groups of vertical baffles are arranged on the inner wall of the stirring tank, the width of the baffles is 1 / 10 of the tank diameter, and the height is 80% of the liquid level height.

[0021] As a preferred technical solution, the ultrasonic treatment in step (5) adopts a dual-frequency composite mode: 20 kHz and 40 kHz work alternately, each frequency acts for 5 min, and pauses for 30 s during the alternation; the insertion depth of the ultrasonic probe is 2 / 3 of the liquid level height, and the power density is controlled at 0.5 - 0.8 W / cm 3 , and the system temperature is maintained ≤ 40°C during the treatment process.

[0022] As a preferred technical solution, the aging process in step (6) adopts a dynamic temperature field: 35°C is maintained for the first 8 h, then it rises to 38°C at a rate of 0.5°C / h for the next 4 h, then drops to 32°C at a rate of 1°C / h, and finally 34 ± 0.5°C is maintained for the last 12 h; the linear velocity of the paddle blade during stirring is controlled at 0.3 - 0.5 m / s, the stirring shaft is designed as a hollow structure, and 35°C circulating water is introduced inside.

[0023] As a preferred technical solution, the whole-process quality monitoring includes: after step (2), the fineness is detected ≤ 15 μm, after step (4), the viscosity deviation is measured ≤ ±5%, and after the aging in step (6) is completed, the fluctuation range of the volume resistivity is tested ≤ ±0.5 order of magnitude; the on-line detection data is uploaded to the MES system in real time, and when any parameter exceeds the set threshold, the process parameter adjustment program is automatically triggered.

[0024] (III) Beneficial effects

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. Through the synergistic effect of the ionic liquid type antistatic agent and the carbon nanotube conductive filler, the volume resistivity of the coating of the present invention , ensuring the stable antistatic ability on the surface of the coating. Compared with traditional antistatic coatings, this solution avoids the problem of attenuation of antistatic performance caused by the migration, loss or influence of environmental humidity of traditional antistatic agents. The surface modification technology of carbon nanotubes is adopted, and the carbon nanotubes are functionalized with silane coupling agents, enabling them to be evenly dispersed in the coating system to form a stable conductive network structure, thereby improving the conductivity uniformity and long-term antistatic effect of the coating. Even after long-term use or mechanical friction, the coating can still maintain stable antistatic performance, avoiding potential safety hazards caused by static electricity accumulation, such as damage to electronic components, spark discharge or dust explosion, etc., meeting the high standards of the electronics manufacturing, precision instruments and explosion-proof places;

[0027] 2. The present invention adopts a solvent-free formulation, completely abandoning common organic solvents in traditional coating systems, such as volatile organic compounds (VOCs) like benzene, toluene, xylene, etc., ensuring that the VOC content of the coating is < 15 g / L, far lower than the national environmental protection regulations (GB18581-2020) and the European and American ROHS and REACH standards, and having excellent environmental protection performance. In terms of system design, all reactive diluents can fully participate in the curing reaction, which not only reduces the release of volatile organic compounds but also improves the denseness and durability of the cured film coating. Compared with traditional solvent-based antistatic coatings, this solution can effectively reduce environmental pollution during construction and the health risks of construction workers, avoiding occupational diseases such as poisoning and allergies caused by long-term contact with organic solvents. In addition, this coating can still maintain good film-forming properties under low-temperature curing conditions, taking into account the needs of energy conservation and consumption reduction while achieving green environmental protection, providing a reliable technical path for the sustainable development of the coating industry;

[0028] 3. Through the strengthening effect of nano-silica fillers, the mechanical strength of the coating of this coating system is greatly improved, enabling it to maintain excellent durability in various harsh application environments. Experimental tests show that the cured coating has a pencil hardness of ≥ 4H, and even under long-term friction, collision or mechanical stress, it will not easily produce scratches or peeling, ensuring a good surface quality for a long time. In addition, the introduction of nano-silica not only enhances the impact resistance of the coating but also optimizes the denseness of the coating, thereby improving its chemical corrosion resistance, enabling it to effectively resist acid, alkali, salt spray and solvent erosion. This improvement in chemical resistance enables this coating to be widely used in fields such as precision electronic equipment, medical devices, and aerospace materials, ensuring the stable performance of the coating during long-term use, extending the service life of equipment, and reducing maintenance costs;

[0029] 4. The present invention adopts an optimized nano-filler dispersion process, including technical means such as gradient dispersion, three-roll grinding, and ultrasonic-assisted defoaming, to ensure the uniform distribution of conductive fillers and antistatic agents in the coating system. Compared with traditional antistatic coatings, this solution effectively reduces the internal stress of the system through dynamic temperature field curing technology, making the coating less likely to settle, delaminate, or agglomerate during storage, ensuring long-term storage stability. During the preparation process, the MES system is used for real-time data monitoring to online monitor key indicators such as the viscosity, fineness, and resistivity of the coating, ensuring the quality consistency of each batch of coatings, thereby improving the reliability of industrial production of the product. The application of this technology enables the coating to maintain uniform physical and chemical properties for a long time, reducing the quality fluctuation problems caused by batch differences. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 is the overall process flow chart of the present invention;

[0032] Figure 2 is the schematic diagram of the pulse feeding system of the present invention;

[0033] Figure 3 is the timing diagram of the dynamic temperature field of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0035] Embodiment 1

[0036] According to the attached Figures 1-3 shown, the present invention provides an antistatic environmentally friendly solvent-free coating and its preparation method. The coating is composed of the following components by mass percentage:

[0037] 30 - 45% of polyurethane acrylate oligomer, 15 - 25% of silicone - modified acrylate resin, 3 - 8% of ionic liquid - type antistatic agent, 0.5 - 2.5% of carbon nanotube conductive filler, 0.3 - 1.2% of nano - silica, 2 - 5% of dispersant, 0.1 - 0.8% of leveling agent, 0.05 - 0.3% of defoaming agent, and the balance is active diluent; among them, the carbon nanotube conductive filler is surface - treated with silane coupling agent, the aspect ratio is controlled at 100 - 200, and the specific surface area ≥ 200m 2 / g; the ionic liquid is a compound of 1 - butyl - 3 - methylimidazolium bis(trifluoromethylsulfonyl)imide and 1 - ethyl - 3 - methylimidazolium tetrafluoroborate in a mass ratio of 2:1; the active diluent is a mixture of trimethylolpropane triacrylate and dipropylene glycol triacrylate in a ratio of 3:2; the volume resistivity of the coating , the VOC content < 15g / L, and the pencil hardness of the cured film ≥ 4H.

[0038] The preparation method includes the following steps:

[0039] (1) Predispersion treatment: Preheat the polyurethane acrylate oligomer and the silicone - modified acrylate resin at 60 - 70°C for 30 min, add the active diluent preheated to 50°C, and stir at 400 - 600 rpm to form a homogeneous base material;

[0040] (2) Gradient dispersion: Add the carbon nanotube conductive filler to the base material in three portions. After each addition, first disperse at a high speed of 1200 rpm for 10 min, and then switch to a three - roll mill for 3 passes of grinding, and the roll gap is adjusted to 50μm, 30μm, and 15μm successively;

[0041] (3) Antistatic system construction: Under nitrogen protection, premix the ionic liquid - type antistatic agent and nano - silica in a ratio of 1:0.3, heat to 80°C at a rate of 0.5°C / min and hold for 15 min, and then inject it into the dispersion system in a pulsed feeding manner;

[0042] (4) Functional additive integration: When the system cools below 45°C, add the dispersant, leveling agent, and defoaming agent in sequence, and mix for 40 min using a planetary mixer with a compound motion mode of 20 rpm for revolution + 800 rpm for rotation;

[0043] (5) Viscosity regulation: Monitor the viscosity of the system through an online rheometer. When the viscosity reaches 1500 - 2000 mPa·s, start the ultrasonic - assisted defoaming device to treat for 15 - 20 min;

[0044] (6) Aging treatment: Transfer the material to a constant - temperature aging tank, and let it stand at 35 ± 2°C for 24 h. During this period, start low - speed stirring for 5 min every 4 h.

[0045] Example 2

[0046] On the basis of Example 1, in step (1), the preheating adopts segmented temperature control: in the first 10 minutes, the temperature is raised to 50 °C at a rate of 2 °C / min, then raised to 65 °C at a rate of 1 °C / min and maintained for 15 minutes, and finally raised to 70 °C at a rate of 0.5 °C / min; the stirring paddle adopts a double-layer serrated structure, the diameter ratio of the lower paddle to the container diameter is 0.6:1, the upper layer is 0.4:1, and the distance between the two paddles is 1 / 3 of the container height.

[0047] In step (2), the timing of adding carbon nanotubes three times is as follows: for the first time, 50% of the total amount is added when the base material temperature reaches 60 °C, the second time 30% is added before the second pass of three-roll grinding, and the third time 20% is added after the grinding is completed; different dispersion procedures are adopted after each addition: for the first time, a dispersion disc with a diameter of Φ25 mm is used, for the second time, it is replaced with a Φ18 mm conical disc, and for the third time, a Φ30 mm flat disc is used.

[0048] Example 3

[0049] On the basis of Example 1, the specific parameters of the pulsed feeding in step (3) are: the feeding frequency is 2 Hz, the single-pulse duration is 0.5 s, the interval time is 1.5 s, the outlet of the feeding pipe is designed as a rotatable fan-shaped nozzle, and the rotation speed is linked with the feeding pump frequency and controlled at 30 - 60 rpm; the nano-silica is pre-treated by plasma, the treatment power is 300 W, the time is 5 min, and a mixed gas with a volume ratio of argon to oxygen of 4:1 is introduced.

[0050] In step (4), the revolution-to-rotation speed ratio of the planetary mixer is controlled according to the time program: 1:40 in the first 10 minutes, adjusted to 1:60 in the middle 20 minutes, and reduced to 1:30 in the last 10 minutes; 6 groups of vertical baffles are arranged on the inner wall of the stirring tank, the width of the baffles is 1 / 10 of the tank diameter, and the height is 80% of the liquid level height.

[0051] In step (5), the ultrasonic treatment adopts a dual-frequency composite mode: 20 kHz and 40 kHz work alternately, each frequency acts for 5 min, and pauses for 30 s during the alternation; the insertion depth of the ultrasonic probe is 2 / 3 of the liquid level height, and the power density is controlled at 0.5 - 0.8 W / cm 3 , and the system temperature is maintained ≤ 40 °C during the treatment process.

[0052] Example 4

[0053] On the basis of Example 1, in step (6), the aging process adopts a dynamic temperature field: maintain 35 °C for the first 8 h, then raise to 38 °C at a rate of 0.5 °C / h for 4 h, then lower to 32 °C at a rate of 1 °C / h, and finally maintain 34 ± 0.5 °C for 12 h; the linear velocity of the paddle blade during stirring is controlled at 0.3 - 0.5 m / s, the stirring shaft is designed as a hollow structure, and 35 °C circulating water is introduced inside.

[0054] The whole-process quality monitoring includes: detecting that the fineness ≤ 15 μm after step (2), measuring that the viscosity deviation ≤ ±5% after step (4), and testing that the fluctuation range of the volume resistivity ≤ ±0.5 order of magnitude after the ripening in step (6); the on-line detection data is uploaded to the MES system in real time, and when any parameter exceeds the set threshold, the process parameter adjustment program is automatically triggered.

[0055] Comparison of the key step parameters of Examples 1 to 4: As shown in the following table:

[0056]

[0057] Table 1 Comparison Table of Key Step Parameters

[0058] Preheat treatment: In Example 2, the resin compatibility is improved by staged temperature control, and the shear effect is enhanced by double-layer paddle blades.

[0059] Carbon nanotube dispersion: In Example 2, carbon nanotubes are added in stages and the size of the dispersion disc is adjusted to improve the uniformity of filler dispersion.

[0060] Antistatic agent addition: In Example 3, pulsed feeding and plasma treatment of nano-SiO2 are used to enhance the interfacial bonding between the antistatic agent and the resin.

[0061] Planetary stirring: In Example 3, the stirring speed ratio is dynamically adjusted, and the mixing efficiency is optimized in combination with the baffle design.

[0062] Ultrasonic degassing: In Example 4, the dual-frequency ultrasonic synergistic effect is used to improve the bubble removal efficiency and avoid overheating.

[0063] Ripening process: In Example 4, through the dynamic temperature field and the temperature-controlled stirring shaft, the system stabilization is promoted.

[0064] Comparison of the key performance indicators of Examples 1 to 4 is shown in the following table:

[0065]

[0066] Table 2 Comparison Table of Key Performance Indicators

[0067] Volume resistivity: In Examples 2 to 4, the resistivity is gradually reduced through process optimization, and the lowest value of 5×10 5 Ω・cm is achieved in Example 4.

[0068] VOC content: Each example meets the environmental protection requirements, and the VOC in Example 4 is further reduced due to the improved dispersion efficiency.

[0069] Hardness of the cured film: In Examples 3 and 4, through the pretreatment of nano-SiO2 and the optimization of the ripening process, the hardness is increased to 3H.

[0070] Dispersion fineness: From Example 2 to Example 4, it is gradually refined to 8 μm, reflecting the improvement of the dispersion process.

[0071] System viscosity: In Example 4, due to the adjustment of the ultrasonic and aging processes, the viscosity range shifts towards higher values but remains controllable.

[0072] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. An antistatic environmentally friendly solvent-free coating, characterized in that: The invention is composed of the following components in percentage by mass: 30-45% of polyurethane acrylate oligomer, 15-25% of organosilicon-modified acrylate resin, 3-8% of ionic liquid antistatic agent, 0.5-2.5% of carbon nanotube conductive filler, 0.3-1.2% of nano silicon dioxide, 2-5% of dispersant, 0.1-0.8% of leveling agent, 0.05-0.3% of defoaming agent, and the balance of active diluent; The carbon nanotube conductive filler is surface treated with a silane coupling agent, the aspect ratio is controlled at 100-200, and the specific surface area is ≥200m 2 / g; the ionic liquid is a mixture of 1-butyl-3-methylimidazolium bistrifluoromethanesulfonyl imide salt and 1-ethyl-3-methylimidazolium tetrafluoroborate in a mass ratio of 2:1; the active diluent is a mixture of trimethylolpropane triacrylate and tripropylene glycol diacrylate in a mass ratio of 3:2; the volume resistivity of the coating is , VOC content <15g / L, cured film pencil hardness ≥4H.

2. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 1, characterized in that: The following steps are involved: (1) Pre-dispersion treatment: preheat the polyurethane acrylate oligomer and the silicone-modified acrylate resin at 60-70°C for 30 minutes, add the active diluent preheated to 50°C, and stir at 400-600 rpm to form a homogeneous base material; (2) Gradient dispersion: Add the carbon nanotube conductive filler to the base material three times. After each addition, disperse it at a high speed of 1200 rpm for 10 min, then switch to a three-roll mill for three passes of grinding, and adjust the roller gap to 50 μm, 30 μm, and 15 μm respectively. (3) Construction of antistatic system: Under nitrogen protection, the ionic liquid antistatic agent and nano-silicon dioxide were premixed in a ratio of 1:0.3, heated to 80°C at a rate of 0.5°C / min and maintained for 15 min, and then injected into the dispersion system by pulse feeding; (4) Integration of functional additives: After the system is cooled to below 45°C, dispersant, leveling agent and defoamer are added in sequence, and mixed for 40 minutes using a planetary mixer in a composite motion mode of revolution 20 rpm + rotation 800 rpm; (5) Viscosity control: Monitor the viscosity of the system through an online rheometer. When the viscosity reaches 1500-2000 mPa·s, start the ultrasonic assisted degassing device for 15-20 minutes; (6) Maturation treatment: Transfer the material to a constant temperature aging tank and place it at 35±2℃ for 24 hours, stirring at a low speed for 5 minutes every 4 hours.

3. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 2, characterized in that: The preheating in step (1) adopts segmented temperature control: the temperature is raised to 50°C at a rate of 2°C / min in the first 10 minutes, then raised to 65°C at a rate of 1°C / min and maintained for 15 minutes, and finally raised to 70°C at a rate of 0.5°C / min; the stirring paddle adopts a double-layer sawtooth structure, the ratio of the lower paddle diameter to the container diameter is 0.6:1, the upper paddle diameter is 0.4:1, and the distance between the two paddles is 1 / 3 of the container height.

4. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 2, characterized in that: The timings of adding carbon nanotubes three times in step (2) are as follows: 50% of the total amount is added for the first time when the temperature of the base material reaches 60°C, 30% is added for the second time before the second pass of three-roller grinding, and 20% is added for the third time after the grinding is completed; different dispersion procedures are used after each addition: a dispersion disk with a diameter of Φ25 mm is used for the first time, replaced with a Φ18 mm conical disk for the second time, and a Φ30 mm flat disk for the third time.

5. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 2, characterized in that: The specific parameters of the pulse feeding in step (3) are: feeding frequency 2 Hz, single pulse duration 0.5 s, interval time 1.5 s, the outlet of the feeding pipe is designed as a rotatable fan-shaped nozzle, the rotation speed is linked with the feeding pump frequency and controlled at 30-60 rpm; the nano-silicon dioxide is pre-treated with plasma, the treatment power is 300 W, the time is 5 min, and a mixed gas with a volume ratio of argon to oxygen of 4:1 is introduced.

6. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 2, characterized in that: In step (4), the speed ratio of the planetary mixer's revolution to rotation is controlled according to a time program: 1:40 in the first 10 minutes, adjusted to 1:60 in the middle 20 minutes, and reduced to 1:30 in the last 10 minutes; 6 sets of vertical baffles are arranged on the inner wall of the mixing tank, the width of the baffles is 1 / 10 of the tank diameter, and the height is 80% of the liquid level.

7. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 2, characterized in that: In step (5), the ultrasonic treatment adopts a dual-frequency composite mode: 20kHz and 40kHz work alternately, each frequency acts for 5 minutes, and pauses for 30 seconds when alternating; the insertion depth of the ultrasonic probe is 2 / 3 of the liquid level, and the power density is controlled at 0.5-0.8W / cm 3 During the treatment process, the system temperature was kept ≤40℃.

8. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 2, characterized in that: In the step (6), the aging process adopts a dynamic temperature field: the temperature is maintained at 35°C for the first 8 hours, then increased to 38°C at a rate of 0.5°C / h for 4 hours, then decreased to 32°C at a rate of 1°C / h, and finally maintained at 34±0.5°C for 12 hours; during stirring, the blade linear speed is controlled at 0.3-0.5m / s, the stirring shaft is designed as a hollow structure, and 35°C circulating water is passed into the interior.

9. The method for preparing an antistatic environmentally friendly solvent-free coating according to claim 2, characterized in that: The whole process quality monitoring includes: after step (2), the fineness is tested to be ≤15μm; after step (4), the viscosity deviation is tested to be ≤±5%; after aging, the volume resistivity fluctuation range is tested to be ≤±0.5 orders of magnitude; the online detection data is uploaded to the MES system in real time, and the process parameter adjustment program is automatically triggered when any parameter exceeds the set threshold.

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