Particle size control equipment of PTFE anti-dripping agent for coating

Abstract

The invention relates to the technical field of high polymer material processing, in particular to particle size control equipment of a PTFE anti-dripping agent for a coating. The system comprises a screening device used for screening PTFE powder with qualified particle size, a pretreatment device used for preparing an emulsion from the PTFE powder, a mixing device used for mixing and reacting the PTFE emulsion and an admixture emulsion, and a granulation device used for drying PTFE and an admixture polymer and forming particles. All devices are seamlessly connected, pollution and energy consumption of intermediate links are reduced, the production efficiency is improved, particle size management is conducted in the whole process from raw material screening to finished product granulation, the dispersity and the acting effect of an anti-dripping agent in the coating are ensured, the synergistic effect of PTFE and an admixture is enhanced through the composite emulsion mixing and drying process, the high temperature resistance, the dripping resistance and the adhesive force of the coating are improved, and the service life of the coating is prolonged. The modular design of the equipment adapts to different productivity requirements, the production cost is reduced, and the equipment is suitable for large-scale popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material processing, and particularly relates to a particle size control device for PTFE anti-dripping agent for coatings. Background Art

[0002] As a key functional additive in the field of coatings, the particle size distribution uniformity of polytetrafluoroethylene (PTFE) anti-dripping agent directly affects the flame retardancy, high temperature resistance and surface flatness of the coating. In the prior art, the particle size control and modification process of PTFE anti-dripping agent mainly rely on traditional methods of mechanical crushing, air flow crushing combined with screening, but there are still significant deficiencies in production efficiency and product uniformity.

[0003] In the prior art, a ball mill or a high-speed shearing device is used to crush PTFE raw materials, the particle size is controlled by adjusting the equipment speed and time, the particle crushing is achieved by the impact of high-speed air flow, and the particles with the target particle size are screened by an internal classification wheel. Most of the prior art adopts an intermittent surface modification process, that is, the PTFE particles and the modifier are stirred and processed in a mixing kettle by feeding. This process relies on operation experience to control the stirring speed, temperature and time, and parameter fluctuations easily lead to uneven thickness of the modified layer, affecting the compatibility between the particles and the coating.

[0004] The random crushing mechanism of traditional mechanical crushing results in a multi-peak distribution of particles. The accuracy of subsequent screening equipment is insufficient, and it is difficult to achieve the goal of monodispersity. The PTFE particles with uneven particle size are prone to local agglomeration or sedimentation in the coating, reducing the anti-dripping efficiency. The sorting efficiency of the air flow crushing and classification system for ultra-fine particles is less than 40%. The residual fine powder is easy to form dust during coating spraying, polluting the production environment, and the coarse particles that are not effectively removed may cause surface defects of the coating. Summary of the Invention

[0005] In order to solve the problem of uneven particle size control during the screening of PTFE particles and improve the automation degree of PTFE modification manufacturing, the present invention provides a particle size control device for PTFE anti-dripping agent for coatings.

[0006] The particle size control device for PTFE anti-dripping agent for coatings provided by the present invention adopts the following technical solutions:

[0007] A particle size control device for PTFE anti-dripping agent for coatings, comprising:

[0008] A screening device for screening PTFE powder with qualified particle size;

[0009] A pretreatment device installed and connected to the tail end of the screening device for making an emulsion of PTFE powder;

[0010] A mixing device is installed and connected to the tail end of a pretreatment device for the mixing reaction of PTFE emulsion and additive emulsion;

[0011] A granulation device is installed and connected to the tail end of the mixing device for drying PTFE and additive polymer and forming particles.

[0012] Remove PTFE powder with unqualified particle size through precise screening to ensure the uniformity of raw materials, avoid problems of emulsion stability or reaction efficiency caused by particle size differences in subsequent processes, improve the consistency of product batches, reduce the impact of impurities on the performance of the final anti-dripping agent, efficiently convert the screened PTFE powder into a uniform and stable emulsion, optimize the dispersibility, provide ideal conditions for subsequent mixing reactions, avoid PTFE agglomeration through a controllable emulsification process, ensure the stability and activity of the emulsion, achieve full and uniform mixing of PTFE emulsion and additive emulsion, promote the reaction efficiency through dynamic stirring or static mixing technology, precisely control the mixing ratio and reaction parameters, ensure the performance consistency of the polymer composite structure, adopt low-temperature drying or spray granulation technology to retain the chemical properties of PTFE and additive polymer, and at the same time form dense particles with controllable particle size, good particle fluidity, convenient for subsequent coating processing, and more stable anti-dripping performance.

[0013] Furthermore, the screening device includes a sieve, a centrifugal classification wheel, a collector and a particle size detector. The sieve, the centrifugal classification wheel and the collector are connected in sequence. The particle size detector is installed in the collector. The sieve is used for rough screening of PTFE particles, and the centrifugal classification wheel is used for fine screening of PTFE particles.

[0014] The sieve conducts rough screening on the PTFE powder, quickly separates large particles or agglomerated materials, reduces the load of the subsequent centrifugal classification wheel, improves the overall screening efficiency, adopts wear-resistant materials, extends the service life, and reduces the maintenance cost. The centrifugal classification wheel conducts fine classification on the roughly screened PTFE powder through the synergistic action of centrifugal force and air flow, precisely separates particles within the target particle size range, can adjust the rotation speed and air volume to adapt to the density and particle size requirements of different PTFE powders, with high flexibility. The collector efficiently collects PTFE powder meeting the particle size requirements, and has an anti-static coating or fluidization structure inside to avoid powder adhesion or secondary agglomeration, and is directly connected to the downstream pretreatment device to achieve continuous production. The particle size detector real-time online monitors the particle size distribution of PTFE powder in the collector, automatically adjusts the sieve mesh number or centrifugal classification wheel parameters through feedback signals to ensure the stability of the finished product, and the data can be recorded and traced to meet strict quality control requirements.

[0015] Furthermore, an ultrasonic vibrator is installed on the screen. The ultrasonic emission end of the ultrasonic vibrator is connected to the surface of the screen and controls the vibration of the screen. A cleaning roller is rotatably arranged on the upper surface of the screen, and the cleaning roller moves along the upper surface of the screen. A pressurized blower is installed above the screen, and the pressurized blower blows air towards the screen to increase the air pressure in the space above the screen. A centrifugal blower is installed at the feed end of the centrifugal classification wheel. An outlet and a recovery port are arranged at the discharge end of the centrifugal classification wheel. The outlet is used to discharge PTFE particles with qualified particle sizes, and the recovery port is used to discharge PTFE particles and impurities with unqualified particle sizes. The collector includes a collection cloth bag, a closed box and a dust precipitator. The collection cloth bag is installed in the closed box. A dust precipitator is installed on one side of the closed box, and the closed box is connected to the external space through the dust precipitator. The particle size detector includes a laser emitter, a scattering detector and an explosion-proof housing. The laser emitter and the scattering detector are arranged opposite to each other, and the laser emitter emits laser towards the scattering detector. PTFE particles pass through the gap between the laser emitter and the scattering detector, and the outer sides of the laser emitter and the scattering detector are enclosed in the explosion-proof housing.

[0016] The high-frequency and micro-amplitude vibration of the ultrasonic vibrator effectively prevents the adhesion or blockage of PTFE powder on the sieve holes, especially suitable for ultra-fine powders. Compared with traditional mechanical vibration, it reduces energy consumption, has more uniform vibration, improves screening efficiency, reduces hard friction, and avoids deformation or damage of the screen. The cleaning roller rolls along the surface of the screen to remove residual particles in real time, avoiding blockage of the sieve holes and ensuring continuous production. The pressing force of the cleaning roller can be adjusted according to the powder characteristics to balance the cleaning effect and screen protection. The pressurized blower increases the air pressure above the screen, promotes the suspension and dispersion of the powder, improves the passing rate of fine powder, suppresses the dust flying downward with the air flow, improves the working environment and reduces raw material loss. The centrifugal blower conveys controllable air flow to the centrifugal classification wheel, enhances the separation effect of centrifugal force on fine particles, dynamically adjusts the air volume according to the density of PTFE, and optimizes the classification accuracy and energy consumption ratio. The outlet accurately collects particles with qualified particle sizes and directly enters the pretreatment device, automatically separating ultra-coarse or ultra-fine particles and impurities, which can be recycled and crushed or discarded, improving the utilization rate of raw materials. The collection cloth bag is made of static electricity eliminating material to avoid PTFE adsorption and ensure complete powder recovery. The dust precipitator filters the residual dust in the discharged gas to meet environmental protection standards. The closed box isolates external oxygen and reduces the risk of PTFE dust explosion. The particle size detector uses the laser scattering method for non-contact measurement, dynamically feeds back and adjusts the screen and centrifugal classification parameters. The explosion-proof housing ensures safe operation in a flammable dust environment, automatically records the particle size distribution curve, and supports quality traceability and process optimization.

[0017] Further, the pretreatment device includes a drying oven, a first emulsion mixing tank, a second emulsion mixing tank, and a third emulsion mixing tank. The drying oven and the first emulsion mixing tank are connected by a conveying device. The drying oven is used to dry PTFE micropowder. The first emulsion mixing tank is used to prepare a PTFE micropowder mixed emulsion. The second emulsion mixing tank and the third emulsion mixing tank are respectively used to prepare a filler emulsion and an auxiliary material emulsion.

[0018] The drying oven evenly dries the PTFE micropowder to avoid the degradation of the PTFE molecular chain caused by high temperature and maintain its chemical stability. The first emulsion mixing tank evenly disperses the PTFE micropowder in a solvent to form a stable emulsion, avoiding the agglomeration of PTFE particles or the demulsification of the emulsion. The second emulsion mixing tank is used to prepare a filler emulsion that synergizes with PTFE, adjusting the filler concentration and viscosity according to the characteristics of the PTFE emulsion to ensure uniform mixing in the subsequent process. The third emulsion mixing tank prepares an auxiliary material emulsion containing additives to solve the interface defect problem in the application of the PTFE emulsion, linking the drying and emulsification processes to achieve continuous production.

[0019] Further, drying lamps, a drying blower, and an electrostatic eliminator are installed in the drying oven. The drying lamps are installed on both sides of the PTFE micropowder conveying path and irradiate and bake towards the PTFE micropowder conveying path. The drying blower is installed on one side of the drying oven and drives the conveying of PTFE micropowder through blowing. The electrostatic eliminator is installed at the bottom of the drying oven to eliminate the static electricity of the PTFE micropowder in the drying oven. Vibration stirrers and heaters are installed in the first emulsion mixing tank, the second emulsion mixing tank, and the third emulsion mixing tank. The vibration stirrers emulsify the solution through vibration.

[0020] The drying lamps use infrared or short-wave drying lamps to directly irradiate the PTFE micropowder conveying path, improving the thermal efficiency and accelerating the drying speed. The adjustable power enables low-temperature drying to avoid the high-temperature denaturation of PTFE and maintain the stable material properties. The bilateral symmetric arrangement eliminates the drying dead angle to ensure that the moisture content of the PTFE micropowder is qualified. The drying blower realizes the suspended conveying of PTFE micropowder through directional blowing, avoiding particle breakage caused by mechanical conveying, and working in coordination with the drying lamps to form a convective heating system to keep the micropowder in a fluidized state, preventing local overheating or caking. The electrostatic eliminator neutralizes the static electricity generated by the PTFE micropowder during the drying process in real time, eliminating the explosion hazard, reducing the micropowder loss caused by static adsorption, and improving the raw material utilization rate. The vibration stirrers achieve nanoscale dispersion through high-frequency and small-amplitude vibration, avoiding damage to the PTFE fiber structure and maintaining its reinforcement effect. Vibration prevents the material from adhering to the wall of the container, reducing maintenance. The heaters maintain the emulsion at the optimal reaction temperature and independently control the temperature according to the requirements of the mixing stage.

[0021] Furthermore, the mixing device includes a production mixing tank, a heating package and a stirring brush, wherein the heating package is wrapped around the outer surface of the production mixing tank and heats the inner area of ​​the production mixing tank, and the stirring brush is movably installed in the production mixing tank and stirs the mixed emulsion in the production mixing tank.

[0022] The heating package uses a flexible heating film or a jacketed structure to wrap the mixing tank to achieve uniform temperature control and avoid local overheating that may cause emulsion demulsification. The intelligent temperature control system can complete the target temperature adjustment in a short time to meet the needs of different reaction stages. The thermal efficiency is high, and the outer insulation material prevents the risk of scalding. The stirring brush effectively and evenly mixes the raw materials to accelerate the reaction.

[0023] Furthermore, the production mixing tank is a closed reactor structure, a quantitative tube is connected to the production mixing tank, the production mixing tank is externally connected to a pretreatment device through the quantitative tube, an injection port is opened on the production mixing tank, the opening and closing of the injection port is controlled by a control valve, the outer side of the heating package is wrapped with a heat-insulating package, and the stirring brush is transmission-connected to a stirring motor.

[0024] The production mixing tank adopts a closed design to prevent external impurities from entering the mixing system, avoid solvent volatilization, reduce raw material loss, facilitate control of the reaction environment, and improve process stability. The quantitative tube realizes accurate metering and transportation of raw materials, ensures the accuracy of the ratio, improves product consistency, and reduces manual operation errors. The injection port and control valve realize controllable feeding to avoid instantaneous excessive concentration, facilitate process adjustment and formula change, and improve operational convenience and safety. The insulation package reduces heat loss, improves energy utilization, maintains temperature stability, ensures reaction uniformity, and improves the safety of the working environment. The stirring motor transmission system provides stable and reliable stirring power, with adjustable speed to meet different process requirements, stable operation, and reduced equipment vibration.

[0025] Furthermore, the granulation device includes a cooling box and a drying box, and the cooling box and the drying box are connected by a conveying device. The cooling box is used to cool the product produced by the mixing device after the reaction, and the drying box is used to remove moisture from the cooled product.

[0026] The cooling box quickly reduces the temperature of the material after the reaction to prevent high temperature from causing changes in material properties, allowing the material to reach a temperature range suitable for subsequent drying treatment, avoiding agglomeration or adhesion of the material due to excessive temperature. The drying box effectively removes residual moisture from the material, controls the moisture content of the final product, ensures product quality, and prevents performance changes caused by moisture during storage. The conveying device achieves seamless connection between the cooling and drying processes, maintains the continuity and stability of material transportation, reduces manual intervention, and improves production efficiency.

[0027] Furthermore, the cooling box is connected to the heat exchanger via a cooling pipe, and a temperature sensor is installed and connected in the cooling box.

[0028] The cooling pipe is connected to the heat exchanger to achieve efficient circulation cooling. The indirect heat exchange method is adopted to avoid direct contact between the cooling medium and the material. The heat exchange area is adjustable to meet the cooling needs of different production capacities. The temperature sensor monitors the temperature changes of the material in the box in real time, provides accurate temperature feedback signals, and provides data support for cooling process control.

[0029] Furthermore, a drying lamp is installed in the drying box, and a humidity sensor is installed and connected in the drying box.

[0030] The drying lamp adopts directional radiation heating to achieve fast and uniform heating of materials. The power output can be adjusted to meet the drying needs of materials with different moisture contents. The energy-saving design has high thermal efficiency and reduces energy consumption. The humidity sensor monitors the humidity changes in the box in real time, accurately feedbacks the degree of material drying, and provides key parameters for drying process control.

[0031] In summary, the present invention has the following beneficial technical effects:

[0032] 1. Each device is seamlessly connected to reduce pollution and energy consumption in the intermediate links, improve production efficiency, and manage the particle size throughout the process from raw material screening to finished product granulation to ensure the dispersibility and effect of the anti-dripping agent in the coating. Through the composite emulsion mixing and drying process, the synergistic effect of PTFE and admixtures is enhanced to improve the high temperature resistance, anti-dripping and adhesion of the coating. The modular design of the equipment is adapted to different production capacity requirements, reducing production costs and suitable for large-scale promotion.

[0033] 2. The coarse screen mesh is combined with the fine screen centrifugal classifying wheel to avoid over-screening or missed screening problems, effectively improving the particle size qualification rate. The particle size detector is linked to adjust the equipment parameters to reduce manual intervention and batch differences. Centrifugal classification replaces the traditional multi-channel vibrating screen, effectively reducing energy consumption and increasing processing speed. It is suitable for PTFE powders of different viscosities and densities, expanding the application range of the equipment.

[0034] 3. The three-stage mixing tank design ensures the independent optimization and precise compounding of PTFE, admixtures and auxiliary material emulsions. The final emulsion stability and compatibility are significantly better than the traditional single-tank process. Drying and emulsification are processed in stages to avoid the impact of fluctuations in the moisture content of PTFE micropowder on the quality of the emulsion. The formula of the admixture and auxiliary material tanks can be adjusted to adapt to different application scenarios.

[0035] 4. The heating package maintains a constant temperature environment, which increases the diffusion rate of PTFE and admixture emulsion molecules, and the stirring brush achieves uniform mixing at the microscopic scale. After the composite emulsion forms a film, the dispersion uniformity of the anti-drip agent in the coating is improved, the temperature resistance of the coating is improved, and the temperature stirring linkage control system automatically matches the process curve to improve product quality consistency.

[0036] 5. Through reasonable control of the cooling and drying processes, ensure that the product has stable physical properties, improve the storage stability of the product, design a continuous cooling and drying process, shorten the production cycle, achieve large-scale production, have reasonable connection of each process, reduce intermediate links, lower energy consumption and production costs, have a high degree of automation, reduce manual operation links, and improve the production environment. Brief Description of the Drawings

[0037] Figure 1 It is a schematic diagram of the external structure of the screening device of the present invention;

[0038] Figure 2 is Figure 1 a schematic diagram of another perspective;

[0039] Figure 3 is Figure 1 a full-sectional view at the central vertical plane of

[0040] Description of the Reference Numerals in the Drawings:

[0041] 1. Screening device, 11. Sieve mesh, 111. Ultrasonic vibrator, 112. Cleaning roller, 113. Pressurized blower, 12. Centrifugal classification wheel, 121. Centrifugal blower, 122. Discharge port, 123. Recovery port, 13. Collector, 131. Collection cloth bag, 132. Enclosed box, 133. Dust precipitator, 14. Particle size detector, 141. Laser emitter, 142. Scattering detector, 143. Explosion-proof shell, 2. Pretreatment device, 21. Drying box, 211. Drying lamp, 212. Drying blower, 213. Static eliminator, 22. First emulsion mixing tank, 201. Vibration stirrer, 202. Heater, 23. Second emulsion mixing tank, 24. Third emulsion mixing tank, 3. Mixing device, 31. Production mixing tank, 311. Quantitative pipe, 312. Feeding port, 32. Heating wrapper, 321. Heat preservation wrapper, 33. Stirring brush, 331. Stirring motor, 4. Granulation device, 41. Cooling box, 411. Heat exchanger, 412. Cooling pipe, 413. Temperature sensor, 42. Drying box, 421. Drying lamp, 422. Humidity sensor. Detailed Embodiments

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the attached Figures 1 - 3 , it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0044] Example 1:

[0045] An embodiment of the present invention discloses a particle size control device for PTFE anti-dripping agent for coatings. Referring to Figure 1 , including:

[0046] A screening device 1 for screening PTFE powder with qualified particle size;

[0047] A pretreatment device 2 installed and connected to the tail end of the screening device 1 for making an emulsion of PTFE powder;

[0048] A mixing device 3 installed and connected to the tail end of the pretreatment device 2 for mixing and reacting the PTFE emulsion with the additive emulsion;

[0049] A granulation device 4 installed and connected to the tail end of the mixing device 3 for drying the PTFE and the additive polymer and forming particles.

[0050] The screening device 1 sets the target particle size range, such as 20 - 50 μm, the pretreatment device 2 configures the emulsifier ratio, the mixing device 3 sets the reaction temperature at 30 - 50 °C and the time at 30 - 90 min, and the granulation device 4 sets the moisture content at the drying end point ≤ 0.5%.

[0051] Material preparation: PTFE powder, emulsifier (such as ammonium perfluorooctanoate), deionized water, additive emulsion (such as polystyrene emulsion).

[0052] Start the screening device 1, evenly feed the PTFE powder into the feed inlet, separate the qualified powder through the sieve mesh, return the unqualified powder to the crushing process, monitor the clogging situation of the sieve mesh in real time, clean the sieve surface every 2 hours, and put the screened PTFE powder, emulsifier, and deionized water into the emulsification kettle of the pretreatment device 2 according to a mass ratio of 10:1:50. Heat it up to 30 ± 5 °C, start high-speed shear stirring (700 rpm) for 40 minutes to form a stable emulsion with a solid content of 15% - 20%. Take samples to detect the particle size and stability of the emulsion. Pump the PTFE emulsion and the admixture emulsion into the mixing device 3 according to a volume ratio of 7:3, adjust the pH to 8 - 9, control the temperature at 45 °C for in-situ polymerization reaction, monitor the viscosity of the mixed solution with an on-line viscometer, and transfer it to the next process after reaching 500 - 800 mPa·s. The granulation device 4 forms the shape, and the mixed material is cooled and dried to remove the solvent to form PTFE modified particles with qualified particle sizes.

[0053] If the sieve mesh is damaged, stop the machine immediately to replace the spare sieve mesh, and trace whether the products in the previous 1 hour are contaminated;

[0054] If the emulsion is stratified, add 0.5% - 1% emulsifier and extend the stirring time by 20%;

[0055] If the particles are sticky, adjust the outlet temperature of the drying tower to decrease by 5 - 10 °C and increase the cooling air volume.

[0056] After the production is completed, stop the machine in reverse order according to the sequence of granulation → mixing → pretreatment → screening. Clean the pipeline with deionized water circulation for 30 minutes, blow the residual powder with a high-pressure air gun, calibrate the temperature sensor weekly, replace the stirring shaft seal ring monthly, and pickle the inner wall of the pretreatment device quarterly.

[0057] Example 2:

[0058] Based on Example 1, add:

[0059] Refer to Figures 1 - 3 , the screening device 1 includes a sieve mesh 11, a centrifugal classification wheel 12, a collector 13, and a particle size detector 14. The sieve mesh 11, centrifugal classification wheel 12, and collector 13 are connected in sequence. The particle size detector 14 is installed in the collector 13. The sieve mesh 11 is used for rough screening of PTFE particles, and the centrifugal classification wheel 12 is used for fine screening of PTFE particles.

[0060] Refer to Figures 1 - 3 , an ultrasonic vibrator 111 is installed on the sieve mesh 11. The ultrasonic emission end of the ultrasonic vibrator 111 is connected to the surface of the sieve mesh 11 to control the vibration of the sieve mesh 11. A cleaning roller 112 is arranged to roll on the upper surface of the sieve mesh 11. The cleaning roller 112 moves along the upper surface of the sieve mesh 11. A pressurized blower 113 is installed above the sieve mesh 11. The pressurized blower 113 blows air towards the sieve mesh 11 to increase the air pressure in the space above the sieve mesh 11;

[0061] One end of the inlet of the centrifugal classification wheel 12 is equipped with a centrifugal blower 121. One end of the outlet of the centrifugal classification wheel 12 is provided with an outlet 122 and a recovery port 123. The outlet 122 is used to discharge PTFE particles with qualified particle sizes, and the recovery port 123 is used to discharge PTFE particles and impurities with unqualified particle sizes.

[0062] The collector 13 includes a collecting cloth bag 131, a closed box 132 and a dust precipitator 133. The collecting cloth bag 131 is installed in the closed box 132. One side of the closed box 132 is equipped with a dust precipitator 133. The closed box 132 is connected to the external space through the dust precipitator 133.

[0063] The particle size detector 14 includes a laser emitter 141, a scattering detector 142 and an explosion-proof housing 143. The laser emitter 141 and the scattering detector 142 are arranged opposite to each other, and the laser emitter 141 emits laser light towards the scattering detector 142. PTFE particles pass through the gap between the laser emitter 141 and the scattering detector 142. The outside of the laser emitter 141 and the scattering detector 142 is enclosed in the explosion-proof housing 143.

[0064] The particle size of PTFE powder is usually in the micron range (10 - 100 μm). Coarse screening is required to remove large particles and agglomerates. A 60 - 100 mesh (aperture 150 - 250 μm) can effectively intercept particles > 150 μm, forming a gradient screening with the subsequent fine sieve of the centrifugal classification wheel (such as 20 - 50 μm) to avoid overload.

[0065] The ultrasonic vibrator 111, frequency: 20 - 40 kHz, power: 200 - 500 W (adjusted according to the sieve area). Ultrasonic vibration can reduce sieve hole blockage. High-frequency vibration of 20 - 40 kHz has a significant effect on the dispersion of PTFE powder. If the power is too small (< 200 W), it cannot effectively clear the blockage. If it is too large (> 500 W), it may damage the sieve.

[0066] The wind speed of the centrifugal blower 121 is 15 - 25 m / s. The wind speed needs to match the separation particle size of the centrifugal classification wheel (such as 20 - 50 μm). According to Stokes' law, if the wind speed is too low (< 15 m / s), fine particles cannot be blown out. If it is too high (> 25 m / s), qualified particles will be misdischarged to the recovery port.

[0067] The oxygen content in the closed box 132 needs to be < 12% (inerted with nitrogen) to prevent dust explosion. Operators need to wear Class A dust-proof masks (filtration efficiency ≥ 99.97%).

[0068] Example 3:

[0069] Based on Example 1, add:

[0070] Reference Figures 1 - 3 The pretreatment device 2 includes a drying oven 21, a first emulsion mixing tank 22, a second emulsion mixing tank 23, and a third emulsion mixing tank 24. The drying oven 21 and the first emulsion mixing tank 22 are connected by a conveying device. The drying oven 21 is used for drying PTFE fine powder. The first emulsion mixing tank 22 is used for preparing a PTFE fine powder mixed emulsion. The second emulsion mixing tank 23 and the third emulsion mixing tank 24 are respectively used for preparing an admixture emulsion and an auxiliary material emulsion.

[0071] Reference Figures 1 - 3 Inside the drying oven 21, a drying lamp 211, a drying blower 212, and a static eliminator 213 are installed. The drying lamp 211 is installed on both sides of the PTFE fine powder conveying path and irradiates and bakes towards the PTFE fine powder conveying path. The drying blower 212 is installed on one side of the drying oven 21 and drives the conveying of PTFE fine powder through blowing. The static eliminator 213 is installed at the bottom of the drying oven 21 and eliminates static electricity of the PTFE fine powder inside the drying oven 21;

[0072] Vibrating stirrers 201 and heaters 202 are installed in the first emulsion mixing tank 22, the second emulsion mixing tank 23, and the third emulsion mixing tank 24. The vibrating stirrers 201 emulsify the solution through vibration stirring.

[0073] Example 4:

[0074] Based on Example 1, add:

[0075] Reference Figures 1 - 3 The mixing device 3 includes a production mixing tank 31, a heating wrap 32, and a stirring brush 33. The heating wrap 32 wraps around the outer surface of the production mixing tank 31 and heats the internal area of the production mixing tank 31. The stirring brush 33 is movably installed in the production mixing tank 31 and stirs the mixed emulsion in the production mixing tank 31.

[0076] Reference Figures 1 - 3 The production mixing tank 31 is of a closed reactor structure. A metering pipe 311 is connected to the production mixing tank 31. The production mixing tank 31 is externally connected to the pretreatment device 2 through the metering pipe 311. A charging port 312 is opened on the production mixing tank 31, and the opening and closing of the charging port 312 are controlled by a control valve;

[0077] A heat preservation wrap 321 is wrapped outside the heating wrap 32;

[0078] The stirring brush 33 is drivingly connected to a stirring motor 331.

[0079] Example 5:

[0080] Based on Example 1, add:

[0081] Referring to Figures 1 - 3 , the granulating device 4 includes a cooling box 41 and a drying box 42. The cooling box 41 and the drying box 42 are connected by a conveying device. The cooling box 41 is used to cool the product after the reaction produced by the mixing device 3, and the drying box 42 is used to remove the moisture of the cooled product.

[0082] Referring to Figures 1 - 3 , the cooling box 41 is connected to a heat exchanger 411 through a cooling pipe 412, and a temperature sensor 413 is installed and connected in the cooling box 41.

[0083] Referring to Figures 1 - 3 , a drying lamp 421 is installed in the drying box 42, and a humidity sensor 422 is installed and connected in the drying box 42.

[0084] The above content is only an example and description of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claim book, they should all belong to the protection scope of the present invention.

Claims

1. A particle size control device for PTFE anti-dripping agent used in coatings, characterized in that, Including: A screening device (1) for screening PTFE powder with qualified particle size; A pretreatment device (2) installed and connected to the tail end of the screening device (1) for making an emulsion of PTFE powder; A mixing device (3) installed and connected to the tail end of the pretreatment device (2) for mixing and reacting the PTFE emulsion with the admixture emulsion; A granulating device (4) installed and connected to the tail end of the mixing device (3) for drying the PTFE and the admixture polymer and forming particles.

2. The particle size control device for the PTFE anti-dripping agent for coatings according to claim 1, characterized in that: The screening device (1) includes a sieve mesh (11), a centrifugal classification wheel (12), a collector (13) and a particle size detector (14). The sieve mesh (11), the centrifugal classification wheel (12) and the collector (13) are connected in sequence. The particle size detector (14) is installed in the collector (13). The sieve mesh (11) is used for coarsely screening PTFE particles, and the centrifugal classification wheel (12) is used for finely screening PTFE particles.

3. The particle size control device of a PTFE anti-dripping agent for coatings according to claim 2, characterized in that: An ultrasonic vibrator (111) is installed on the sieve mesh (11). One ultrasonic transmitting end of the ultrasonic vibrator (111) is connected to the surface of the sieve mesh (11) to control the vibration of the sieve mesh (11). A cleaning roller (112) is arranged to roll on the upper surface of the sieve mesh (11). The cleaning roller (112) moves along the upper surface of the sieve mesh (11). A pressurized blower (113) is installed above the sieve mesh (11). The pressurized blower (113) blows air towards the sieve mesh (11) to increase the air pressure in the space above the sieve mesh (11); A centrifugal blower (121) is installed at the feeding end of the centrifugal classification wheel (12). An outlet (122) and a recovery port (123) are arranged at the discharging end of the centrifugal classification wheel (12). The outlet (122) is used for discharging PTFE particles with qualified particle size, and the recovery port (123) is used for discharging PTFE particles and impurities with unqualified particle size; The collector (13) includes a collecting cloth bag (131), a closed box (132) and a dust precipitator (133). The collecting cloth bag (131) is installed in the closed box (132). A dust precipitator (133) is installed on one side of the closed box (132). The closed box (132) is connected to the external space through the dust precipitator (133); The particle size detector (14) includes a laser emitter (141), a scattering detector (142) and an explosion-proof housing (143). The laser emitter (141) and the scattering detector (142) are arranged opposite to each other, and the laser emitter (141) emits laser towards the scattering detector (142). The PTFE particles pass through the gap between the laser emitter (141) and the scattering detector (142). The laser emitter (141) and the scattering detector (142) are enclosed in the explosion-proof housing (143) on the outside.

4. The particle size control device for a PTFE anti-dripping agent for coatings according to claim 1, characterized in that: The pretreatment device (2) comprises a drying box (21), a first emulsion mixing tank (22), a second emulsion mixing tank (23) and a third emulsion mixing tank (24); the drying box (21) and the first emulsion mixing tank (22) are connected via a conveying device; the drying box (21) is used for drying PTFE micropowder; the first emulsion mixing tank (22) is used for preparing PTFE micropowder mixed emulsion; the second emulsion mixing tank (23) and the third emulsion mixing tank (24) are used for preparing admixture emulsion and auxiliary material emulsion, respectively.

5. The particle size control device of a PTFE anti-dripping agent for coatings according to claim 4, characterized in that: The drying box (21) is equipped with a drying lamp (211), a drying blower (212) and a static eliminator (213); the drying lamp (211) is installed on both sides of the PTFE micropowder conveying path and irradiates and bakes the PTFE micropowder conveying path; the drying blower (212) is installed on one side of the drying box (21) and drives the PTFE micropowder to be conveyed by blowing air; the static eliminator (213) is installed at the bottom of the drying box (21) and eliminates static electricity on the PTFE micropowder in the drying box (21); A vibration stirrer (201) and a heater (202) are installed in the first emulsion mixing tank (22), the second emulsion mixing tank (23) and the third emulsion mixing tank (24), and the vibration stirrer (201) stirs the emulsified solution by vibration.

6. The particle size control device for a PTFE anti-dripping agent for coatings according to claim 1, characterized in that: The mixing device (3) comprises a production mixing tank (31), a heating package (32) and a stirring brush (33), wherein the heating package (32) is wrapped around the outer surface of the production mixing tank (31) and heats the inner area of ​​the production mixing tank (31), and the stirring brush (33) is movably installed in the production mixing tank (31) and stirs the mixed emulsion in the production mixing tank (31).

7. The particle size control device of a PTFE anti-dripping agent for coatings according to claim 6, characterized in that: The production mixing pool (31) is a closed reactor structure. A quantitative pipe (311) is connected to the production mixing pool (31). The production mixing pool (31) is externally connected to the pretreatment device (2) through the quantitative pipe (311). A material injection port (312) is opened on the production mixing pool (31). The opening and closing of the material injection port (312) is controlled by a control valve. The heating package (32) is wrapped with a heat-insulating package (321) on the outside; The stirring brush (33) is transmission-connected to the stirring motor (331).

8. The particle size control device of a PTFE anti-dripping agent for coatings according to claim 1, characterized in that: The granulating device (4) comprises a cooling box (41) and a drying box (42), wherein the cooling box (41) and the drying box (42) are connected via a conveying device, wherein the cooling box (41) is used to cool the product produced by the mixing device (3) after the reaction, and the drying box (42) is used to remove moisture from the cooled product.

9. The particle size control device of a PTFE anti-dripping agent for coatings according to claim 8, characterized in that: The cooling box (41) is connected to the heat exchanger (411) via a cooling pipe (412), and a temperature sensor (413) is installed and connected in the cooling box (41).

10. The particle size control device of a PTFE anti-dripping agent for coatings according to claim 8, characterized in that: A drying lamp (421) is installed in the drying box (42), and a humidity sensor (422) is installed and connected in the drying box (42).

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