A production equipment for producing modified plastics using anti-agglomeration nano-metal powder.

Abstract

This invention discloses a mixing and production equipment for modifying plastics with anti-agglomeration nano-metal powder. The equipment comprises, sequentially along the material flow direction, an in-situ vapor-phase coating pretreatment integrated feeding mechanism, an ultrasonic pulse pressure dual-field coupled anti-agglomeration mixing system, and a gradient variable pitch flexible mixing screw structure. The feeding mechanism performs vapor-phase coating on the powder under negative pressure, forming an isolation film. The mixing system promotes micro-agglomeration through low-frequency ultrasonic cavitation effect and macro-dispersion through periodic deformation of the pulse pressure field. The screw structure employs a three-stage design: large-pitch loose feeding, high-frequency weak shear deagglomeration, and small-pitch homogenization, avoiding damage to powder grains. The equipment is also equipped with an adaptive intelligent control system that automatically identifies materials and dynamically optimizes process parameters. It also features a removable cleaning mechanism for easy maintenance. This equipment achieves efficient, non-destructive, and uniform dispersion of nano-powders in a plastic matrix, significantly improving the performance stability and production continuity of modified plastics.

Description

Technical Field

[0001] This invention relates to the field of polymer material processing technology, specifically to a production equipment for mixing and modifying plastics with anti-agglomeration nano-metal powder. Background Technology

[0002] Nanoparticles of metals (such as silver, copper, and nickel) are widely used in the preparation of functional modified plastics due to their excellent electrical and thermal conductivity, meeting the demand for high-performance materials in fields such as electronics, aerospace, and new energy vehicles. However, due to their extremely small particle size, huge specific surface area, and extremely high surface energy, nanoparticles of metals are prone to agglomeration due to van der Waals forces and other factors, forming soft or hard agglomerates. This agglomeration problem directly leads to poor dispersion uniformity of nanoparticles in the plastic matrix, seriously affecting the stability of the core properties of modified plastics, such as electrical and thermal conductivity, and has become a key technical bottleneck restricting the industrialization of nanoparticle-modified plastics.

[0003] In existing technologies, the compounding and production of plastics modified with nano-metal powders mainly relies on traditional compounding equipment, such as internal mixers and screw extruders. These devices typically employ a passive dispersion mode using single mechanical shearing or fly knife dispersal, dispersing the nano-metal powder into the plastic melt through the shearing and kneading action of the screw. However, existing equipment has the following significant shortcomings: First, the dispersion ability is insufficient. Traditional mixing equipment has limited mechanical shear force, making it difficult to effectively deagglomerate the micron-sized clusters of nano-metal powder into particles of the original nano-size. Even after multiple mixing processes, a large number of agglomerates remain, resulting in poor dispersion uniformity of the powder in the plastic matrix and a significant reduction in the modification effect.

[0004] Second, powder damage is severe. Traditional equipment often requires high shear strength to achieve powder dispersion, but this inevitably leads to the breakage of nanoscale metal powder grains, performance degradation, and loss of the functional advantages at the nanoscale. At the same time, the fixed structure of traditional screws results in insufficient shearing at the front and excessive shearing at the back, making it difficult to balance dispersion effect and powder protection.

[0005] Third, the equipment has poor adaptability. Nano-metal powders of different particle sizes and materials have significantly different requirements for mixing process parameters. Traditional equipment operates with fixed parameters and cannot adapt to the needs of different materials. Material change and debugging are cumbersome and batch stability is poor.

[0006] Fourth, powder adhesion and accumulation are serious problems. Nano-metal powders tend to adhere to the screw surface during the mixing process, leading to accumulation and carbonization over long-term production, which in turn causes batch-to-batch agglomeration defects, seriously affecting the consistency of product quality and the stability of continuous equipment operation.

[0007] To address the aforementioned issues, there is an urgent need to develop a nano-metal powder modified plastic compounding production equipment that can effectively suppress the agglomeration of nano-metal powders from the source, achieve uniform dispersion at the microscale, protect the original structure of the powder, adapt to various types of materials, and have good operational stability. Summary of the Invention

[0008] The purpose of this invention is to provide a production equipment for mixing modified plastics with anti-agglomeration nano-metal powder, so as to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a production equipment for mixing and modifying plastics with anti-agglomeration nano-metal powder, comprising, arranged sequentially along the material flow direction: an in-situ gas phase coating pretreatment integrated feeding mechanism, an ultrasonic pulse pressure dual-field coupling anti-agglomeration mixing system, and a gradient variable pitch flexible mixing screw structure; The in-situ vapor phase coating pretreatment integrated feeding mechanism includes a closed negative pressure feeding chamber, a vapor phase coating unit, and a micro-weight loss precision side feeding unit; the closed negative pressure feeding chamber is a sealed structure with a powder feeding mechanism at the top, and the inside of the chamber maintains a negative pressure environment; the vapor phase coating unit includes a gas mixer, an atomizing nozzle, and a flow controller. The ultrasonic pulse pressure dual-field coupling anti-agglomeration mixing system includes a first mixing chamber, a second mixing chamber, a distributed ultrasonic transducer assembly, and a pulse stator-rotor assembly. Both the first and second mixing chambers are closed cylindrical cavities and are interconnected. The front end of the first mixing chamber has a plastic matrix inlet and a nano-metal powder inlet, which are connected to the outlet of the micro-weight loss precision side feeding unit. The rear end of the second mixing chamber has a mixed material outlet. Electric heating plates are installed inside the walls of both the first and second mixing chambers. The distributed ultrasonic transducer assembly includes multiple ultrasonic transducers and an ultrasonic generator distributed along the axial and circumferential directions of the first mixing chamber. Each ultrasonic transducer is fixedly installed on the outer wall of the first mixing chamber, and each ultrasonic transducer is driven by the ultrasonic generator and its start / stop and power are independently controlled. The gradient variable pitch flexible mixing screw structure is rotatably mounted inside the second mixing chamber via a transmission mechanism, and sequentially includes a feeding loosening section, a pulse shearing section, and a homogenizing plasticizing section along the material flow direction; the feeding loosening section adopts a large pitch structure; the pulse shearing section adopts a staggered asymmetric kneading blocks and a micro-pulse groove structure, with each kneading block arranged asymmetrically in the screw axis, and the micro-pulse grooves disposed on the screw surface between the kneading blocks, forming a periodic groove structure; the homogenizing plasticizing section adopts a small pitch structure.

[0010] Preferably, the inlet of the gas mixer is connected to an inert gas source, a coupling agent source, and a dispersant source via pipelines, respectively. The outlet of the gas mixer is provided with an atomizing nozzle, which is fixedly installed on the inner wall of the sealed negative pressure feeding chamber. The flow controller is located on the pipeline. The micro-loss-of-weight precision side feeding unit is located at the outlet of the gas phase coating unit, and its input end is connected to the outlet of the gas phase coating unit. The micro-loss-of-weight precision side feeding unit has a built-in feeding screw driven by a drive motor and a micro-loss-of-weight metering module, and the micro-loss-of-weight metering module is electrically connected to the drive motor.

[0011] Preferably, the negative pressure environment inside the sealed negative pressure feeding chamber is -0.01 to -0.05 MPa; the inert carrier gas output from the inert gas source, the gaseous coupling agent output from the coupling agent source, and the gaseous dispersant output from the dispersant source are mixed in the gas mixer at a volume ratio of 100:1 to 5:0.5 to 2, and then atomized and sprayed into the sealed negative pressure feeding chamber through the atomizing nozzle.

[0012] Preferably, the pulse stator-rotor assembly includes a stator fixedly disposed on the inner wall of the first mixing chamber, a rotor rotatably disposed inside the first mixing chamber, and a servo motor for driving the rotor to rotate. The inner surface of the stator is provided with periodic protrusions, and the outer surface of the rotor is provided with periodic grooves. A pulse deformation gap is formed between the protrusions and the grooves.

[0013] Preferably, the pitch of the feed loosening section is 1.5 to 3 times the pitch of the homogenizing plasticizing section; the entire surface of the screw is provided with a nano-ceramic passivation modification layer.

[0014] Preferably, the transmission mechanism includes a side support plate, a transmission rod, a chain gear transmission assembly, a first bevel gear, and a second bevel gear; the side support plate is fixedly connected to the outside of the first mixing chamber; the transmission rod is rotatably connected to the surface of the side support plate, the upper end of the transmission rod is connected to the servo motor via the chain gear transmission assembly, and the lower end of the transmission rod is fixedly connected to the first bevel gear; the second bevel gear is rotatably connected to the outside of the second mixing chamber, and the first bevel gear and the second bevel gear mesh and transmit power; the second bevel gear is connected to the end of the gradient variable pitch flexible mixing screw structure.

[0015] Preferably, a screw cleaning mechanism is provided on the outside of the second mixing chamber. The screw cleaning mechanism includes an electric telescopic rod, a U-shaped rod, a cleaning nozzle, a spring, a limiting hexagonal post, and a hexagonal groove. The cleaning nozzle faces the outlet of the mixed material. The electric telescopic rod is fixedly installed on the outside of the second mixing chamber. One end of the U-shaped rod is fixedly connected to the telescopic end of the electric telescopic rod, and the other end of the U-shaped rod is rotatably connected to the end of the gradient variable pitch flexible mixing screw structure. The hexagonal groove is provided at the end of the gradient variable pitch flexible mixing screw structure away from the U-shaped rod. A cavity is provided at the rotating end of the second bevel gear. The limiting hexagonal post is slidably connected in the cavity. The spring is fixedly connected between the limiting hexagonal post and the inner wall of the cavity, and the limiting hexagonal post can engage with the hexagonal groove.

[0016] Preferably, the end of the limiting hexagonal prism is chamfered.

[0017] Preferably, the system further includes a material adaptive anti-agglomeration intelligent control system, which comprises a material identification module, a database module, a parameter self-regulation module, and an online monitoring feedback module. The material identification module is located at the entrance of the powder feeding mechanism and includes a near-infrared spectroscopy detection unit. The database module has a built-in database of nano-metal powder mixing processes. The parameter self-regulation module is electrically connected to the material identification module, the database module, the ultrasonic generator, the servo motor, the electric heating plate, and the flow controller, respectively. The online monitoring feedback module includes a viscosity sensor, a density sensor, and a pressure sensor located in the first mixing chamber and the second mixing chamber, and is electrically connected to the parameter self-regulation module.

[0018] Preferably, the process database built into the database module covers the optimal combination of process parameters for different types, particle sizes, and filling ratios of nano-metal powders during the mixing process. The process parameters include the ultrasonic power of the ultrasonic generator, the driving speed of the servo motor, the heating temperature of the electric heating plate, and the output gas flow rate of the flow controller. The parameter self-regulation module calls the matching data in the database module according to the identification result of the material identification module, automatically sets the initial values ​​of each core process parameter, and uses an adaptive control algorithm of neural network to dynamically correct the current process parameters.

[0019] Beneficial effects This invention provides a production equipment for mixing and modifying plastics with anti-agglomeration nano-metal powder, which has the following beneficial effects: 1. This anti-agglomeration nano-metal powder modified plastic mixing production equipment, by setting up an integrated feeding mechanism with in-situ gas phase coating pretreatment, performs single-layer gas phase coating treatment on the nano-metal powder before it enters the mixing system, forming a dense isolation coating film on the powder surface, blocking the van der Waals adsorption between powder particles from the source, and effectively inhibiting the generation of agglomeration.

[0020] 2. This anti-agglomeration nano-metal powder modified plastic mixing production equipment uses an ultrasonic pulse pressure dual-field coupled anti-agglomeration mixing system. It utilizes the cavitation effect of low-frequency ultrasound to tear apart agglomerates at the micro level, while using the periodic volume deformation of the pulse pressure field to promote macro-dispersion. This achieves a synergistic effect of micro-deagglomeration and macro-dispersion, and the dispersion effect is significantly better than the traditional single mechanical shearing mode.

[0021] 3. This anti-agglomeration nano-metal powder modified plastic mixing production equipment adopts a high-frequency, weak-shear design concept through a gradient variable pitch adaptive flexible mixing screw structure. It achieves dispersion by increasing the shear frequency rather than increasing the intensity of a single shear, effectively avoiding strong hard shear damage to the nano-metal powder grains and protecting the nanoscale functional advantages of the powder.

[0022] 4. This anti-agglomeration nano-metal powder modified plastic mixing production equipment, through the setting of a material adaptive anti-agglomeration intelligent control system, can automatically identify material parameters, call the database to match the optimal process parameters, monitor the mixing status in real time and dynamically correct the process parameters, realizing full-process adaptive intelligent control, eliminating the need for repeated manual debugging, and significantly improving the equipment's adaptability to different types of materials and batch stability.

[0023] 5. This anti-agglomeration nano-metal powder modified plastic mixing production equipment, through the setting of a screw cleaning mechanism, allows for automatic cleaning of the variable pitch flexible mixing screw structure when cleaning is required. The extension of the electric telescopic rod moves the screw structure out of the mixing material outlet, and water is sprayed from the cleaning nozzle for automatic cleaning. After cleaning, the retraction of the electric telescopic rod allows the screw structure to be reinstalled. The spring extension, combined with the rotation of the second bevel gear, automatically inserts the hexagonal pinion into the hexagonal slot. The entire cleaning process is automated, facilitating equipment maintenance and effectively preventing nano-metal powder from easily adhering to the inner wall of the screw during long-term production. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of a plastic mixing production equipment for anti-agglomeration nano-metal powder modification proposed in this invention. Figure 2 This is a schematic diagram of the in-situ vapor phase coating pretreatment integrated feeding mechanism of the anti-agglomeration nano-metal powder modified plastic compounding production equipment proposed in this invention. Figure 3This is a three-dimensional structural diagram of the first and second mixing chambers of a plastic mixing production equipment for preventing agglomeration of nano-metal powder proposed in this invention. Figure 4 This is a schematic diagram of the gradient variable pitch flexible mixing screw structure of the anti-agglomeration nano-metal powder modified plastic mixing production equipment proposed in this invention; Figure 5 This is a cross-sectional view of the powder feeding mechanism of a production equipment for anti-agglomeration nano-metal powder modified plastics, as proposed in this invention. Figure 6 This is a schematic diagram of the second bevel gear structure in a plastic mixing production equipment for preventing agglomeration of nano-metal powder proposed in this invention. Figure 7 This is a structural block diagram of a material adaptive anti-agglomeration intelligent control system for a plastic mixing production equipment using anti-agglomeration nano-metal powder, as proposed in this invention.

[0025] In the diagram: 1. In-situ vapor phase coating pretreatment integrated feeding mechanism; 2. Ultrasonic pulse pressure dual-field coupling anti-agglomeration mixing system; 3. Gradient variable pitch flexible mixing screw structure; 4. Screw cleaning mechanism; 5. Sealed negative pressure feeding chamber; 6. Vapor phase coating unit; 7. Micro-weight loss precision side feeding unit; 8. Powder feeding mechanism; 9. Gas mixer; 10. Atomizing nozzle; 11. Flow controller; 12. First mixing chamber; 13. Second mixing chamber; 14. Distributed ultrasonic transducer assembly; 15. Plastic matrix. 16. Inlet; 17. Mixed material outlet; 18. Electric heating plate; 19. Stator; 20. Rotor; 21. Servo motor; 22. Feeding loosening section; 23. Pulse shearing section; 24. Homogenizing and plasticizing section; 25. Kneading block; 26. Pulse groove; 27. Transmission rod; 28. Chain gear transmission assembly; 29. ​​First bevel gear; 30. Second bevel gear; 31. Chamfer; 32. Electric telescopic rod; 33. U-shaped rod; 34. Cleaning nozzle; 35. Spring; 36. Limiting hexagonal column; 37. Hexagonal groove. Detailed Implementation

[0026] 1. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] Example 1, please refer to Figures 1 to 7 The present invention provides a technical solution: a production equipment for mixing modified plastics with anti-agglomeration nano-metal powder, comprising, arranged sequentially along the material flow direction: an in-situ gas phase coating pretreatment integrated feeding mechanism 1, an ultrasonic pulse pressure dual-field coupling anti-agglomeration mixing system 2, a gradient variable pitch flexible mixing screw structure 3, and a material adaptive anti-agglomeration intelligent control system.

[0030] I. In-situ vapor phase coating pretreatment integrated feeding mechanism The in-situ vapor phase coating pretreatment integrated feeding mechanism 1 includes a sealed negative pressure feeding chamber 5, a vapor phase coating unit 6, and a micro-weight loss precision side feeding unit 7.

[0031] The sealed negative pressure feeding chamber 5 is a sealed chamber with a powder feeding mechanism 8 (using a powder feeding device from the prior art) at its top for receiving nano-metal powder raw materials. The chamber maintains a negative pressure environment, preferably -0.01 to -0.05 MPa, to prevent the nano-metal powder from escaping and to facilitate the uniform distribution of the gas-phase coating medium and its full contact with the powder.

[0032] The gas phase coating unit 6 includes a gas mixer 9, an atomizing nozzle 10, and a flow controller 11. The inlet of the gas mixer 9 is connected via pipes to an inert gas source (such as nitrogen or argon), a coupling agent source (such as silane coupling agents KH-550, KH-570, or titanate coupling agents), and a dispersant source (such as polymeric dispersants BYK-110, BYK-111, etc.). The outlet of the gas mixer 9 is equipped with an atomizing nozzle 10, which is fixedly installed on the inner wall of the sealed negative pressure feed chamber 5. The flow controller 11 is located on the pipes and is used to precisely control the flow rate of each gas. The inert carrier gas from the inert gas source, the gaseous coupling agent from the coupling agent source, and the gaseous dispersant from the dispersant source are precisely mixed in the gas mixer 9 according to a predetermined ratio, and then atomized and sprayed into the sealed negative pressure feed chamber 5 through the atomizing nozzle 10. The preferred mixing ratio is a volume ratio of 100:1 to 5:0.5 to 2.

[0033] The micro-loss-of-weight precision side-feeding unit 7 is located at the outlet of the vapor phase coating unit 6, and its input end is connected to the outlet end of the vapor phase coating unit 6. The micro-loss-of-weight precision side-feeding unit 7 internally houses a feed screw driven by a drive motor and a micro-loss-of-weight metering module, and the micro-loss-of-weight metering module is electrically connected to the drive motor.

[0034] During operation, the nano-metal powder enters the sealed negative pressure feeding chamber 5 from the top powder feeding mechanism 8, and is dispersed in a fluidized state under negative pressure. The atomized gaseous coating medium sprayed from the atomizing nozzle 10 comes into full contact with the fluidized nano-metal powder, forming a uniform monolayer coating film on the powder surface. The coating treatment time is 1 to 10 seconds (preferably 3 seconds), and the coating film thickness is a monolayer thickness (approximately 1 to 5 nm). This monolayer coating film forms a chemical bond with the surface of the nano-metal powder through one end of the coupling agent molecule, while the other end has good compatibility with the plastic matrix, thereby both blocking the van der Waals adsorption between powder particles and improving the interfacial bonding between the powder and the plastic melt.

[0035] The nano-metal powder, after being treated with vapor phase coating, enters the micro-weight loss precision side feeding unit 7. The micro-weight loss metering module detects the rate of change of powder weight in the micro-weight loss precision side feeding unit 7 in real time, and precisely controls the rotation speed of the feeding screw to achieve uniform and precise conveying of powder, greatly reducing problems such as powder dust, stratification, and material blockage.

[0036] II. Ultrasonic Pulse Pressure Dual-Field Coupling Anti-Agglomeration Mixing System The ultrasonic pulse pressure dual-field coupling anti-agglomeration mixing system 2 includes a first mixing chamber 12, a second mixing chamber 13, a distributed ultrasonic transducer assembly 14, and a pulse stator-rotor assembly.

[0037] The first mixing chamber 12 and the second mixing chamber 13 are both closed cylindrical cavities and are interconnected. The front end of the first mixing chamber 12 has a plastic matrix inlet 15 and a pretreated nano-metal powder inlet, which is connected to the outlet of the micro-weight loss precision side feeding unit 7. The rear end of the second mixing chamber 13 has a mixed material outlet 16. Both the first mixing chamber 12 and the second mixing chamber 13 are equipped with electric heating plates 17 inside their walls to heat the material within the cavities to above the melting temperature of the plastic matrix; the preferred heating temperature is 150–350°C.

[0038] The distributed ultrasonic transducer assembly 14 includes multiple ultrasonic transducers and ultrasonic generators distributed along the axial and circumferential directions of the first mixing chamber 12. Each ultrasonic transducer is fixedly installed on the outer wall of the first mixing chamber 12. Each ultrasonic transducer is driven by the ultrasonic generator, and the start, stop and power of the ultrasonic transducer are independently controlled. The ultrasonic power of the ultrasonic generator is preferably 100 to 1000 W.

[0039] During operation, the ultrasonic transducer emits low-frequency ultrasonic waves of 20–30 kHz (preferably 25 kHz) into the first mixing chamber 12. When these low-frequency ultrasonic waves propagate through the plastic melt, they generate a cavitation effect. The periodic compression and stretching of the ultrasonic waves cause a large number of tiny bubbles to form inside the melt. These bubbles grow in the negative pressure phase of the ultrasonic waves and collapse in the positive pressure phase. The collapse instant generates extremely high local temperatures and pressures (local temperatures can reach over 5000 K, and pressures can reach over 50 MPa), forming strong shock waves and microjets that tear apart the agglomerates of nano-metal powder at the microscopic level, achieving efficient deagglomeration. Simultaneously, compared to high-frequency ultrasound, low-frequency ultrasound (20–30 kHz) significantly reduces the thermal effect, effectively preventing the oxidation of nano-metal powder due to heat generation.

[0040] The pulse stator-rotor assembly includes a stator 18 fixedly disposed on the inner wall of the first mixing chamber 12, a rotor 19 rotatably disposed inside the first mixing chamber 12, and a servo motor 20 driving the rotor 19 to rotate. The driving speed of the servo motor 20 is preferably 50 to 500 rpm.

[0041] The inner surface of the stator 18 has periodic protrusions, and the outer surface of the rotor 19 has periodic grooves. A pulse deformation gap is formed between the protrusions and the grooves.

[0042] During rotation, due to the special surface design of the stator 18 and rotor 19, the volume of the pulse deformation gap undergoes periodic changes, thereby causing dynamic expansion and contraction of the working volume of the first mixing chamber 12. This periodic volume deformation generates intermittent compression, stretching, and turbulence on the melt within the chamber, promoting the macroscopic dispersion of nano-metal powder in the plastic melt and providing more favorable mass transfer conditions for the ultrasonic cavitation effect. The ultrasonic field and the pulsed pressure field work synergistically to achieve the dual effect of "microscopic deagglomeration and macroscopic dispersion".

[0043] III. Gradient Variable Pitch Flexible Mixing Screw Structure The gradient variable pitch flexible mixing screw structure 3 is rotatably installed inside the second mixing chamber 13 through a transmission mechanism, and sequentially includes a feeding loosening section 21, a pulse shearing section 22 and a homogenizing plasticizing section 23 along the material flow direction.

[0044] The feeding loosening section 21 adopts a large-pitch structure (the pitch is 1.5 to 3 times that of the homogenizing plasticizing section 23, preferably 2 times), and operates at a lower speed. The large-pitch design enhances the screw's ability to push materials while reducing the compression effect, preventing the nano-metal powder from accumulating and agglomerating due to compression during the feeding stage, and ensuring that the powder enters the mixing zone in a loose state.

[0045] The pulse shearing section 22 employs a staggered asymmetric kneading blocks 24 and micro-pulse grooves 25. The staggered angle of the staggered asymmetric kneading blocks 24 is 30° to 60° (preferably 45°), and each kneading block 24 is asymmetrically arranged along the screw axis, subjecting the melt to multi-directional and multi-angle shearing action as it flows through this section. The micro-pulse grooves 25 are located on the screw surface between the kneading blocks 24, forming a periodic groove structure, generating local pressure pulsations and turbulence as the melt flows through. By increasing the frequency of shearing action rather than increasing the intensity of a single shearing action, residual micro-agglomerates are broken up, thereby avoiding strong hard shear damage to the nano-metal powder grains while ensuring dispersion effect.

[0046] The homogenization and plasticizing section 23 adopts a small pitch structure to uniformly distribute the fully dispersed nano-metal powder in the plastic melt at the nanoscale, thus completing the final homogenization and mixing.

[0047] The screw's overall surface is covered with a nano-ceramic passivation modification layer. The low surface energy of the nano-ceramic coating effectively reduces the adhesion and accumulation of nano-metal powder on the screw surface, ensuring long-term operational stability and batch-to-batch product consistency.

[0048] The transmission mechanism includes a side support plate, a transmission rod 26, a chain gear transmission assembly 27, a first bevel gear 28, and a second bevel gear 29. The side support plate is fixedly connected to the outside of the first mixing chamber 12. The transmission rod 26 is rotatably connected to the surface of the side support plate. The upper end of the transmission rod 26 is connected to the servo motor 20 via the chain gear transmission assembly 27, and the lower end of the transmission rod 26 is fixedly connected to the first bevel gear 28. The second bevel gear 29 is rotatably connected to the outside of the second mixing chamber 13, and the first bevel gear 28 and the second bevel gear 29 mesh and transmit power. The second bevel gear 29 is connected to the end of the gradient variable pitch flexible mixing screw structure 3. Thus, while driving the rotor 19 to rotate, the servo motor 20 simultaneously drives the gradient variable pitch flexible mixing screw structure 3 to rotate via the transmission mechanism, achieving multiple uses of a single power source.

[0049] A screw cleaning mechanism 4 is provided on the outer side of the second mixing chamber 13. The screw cleaning mechanism 4 includes an electric telescopic rod 31, a U-shaped rod 32, a cleaning nozzle 33, a spring 34, a limiting hexagonal post 35, and a hexagonal groove 36. The cleaning nozzle 33 faces the mixing material outlet 16. The electric telescopic rod 31 is fixedly installed on the outer side of the second mixing chamber 13. One end of the U-shaped rod 32 is fixedly connected to the telescopic end of the electric telescopic rod 31, and the other end of the U-shaped rod 32 is rotatably connected to the end of the gradient variable pitch flexible mixing screw structure 3. The end of the gradient variable pitch flexible mixing screw structure 3 away from the U-shaped rod 32 has a hexagonal groove 36. The rotating end of the second bevel gear 29 has a cavity, the limiting hexagonal post 35 is slidably connected in the cavity, the spring 34 is fixedly connected between the limiting hexagonal post 35 and the inner wall of the cavity, and the limiting hexagonal post 35 can be engaged with the hexagonal groove 36. The end of the limiting hexagonal post 35 is chamfered 30 so that the limiting hexagonal post 35 can be inserted into the hexagonal groove 36.

[0050] When cleaning is required for the gradient variable pitch flexible mixing screw structure 3, the extension of the electric telescopic rod 31 and the spraying of water (or cleaning solution) by the cleaning nozzle 33 can be controlled. The extension of the electric telescopic rod 31 allows the gradient variable pitch flexible mixing screw structure 3 to be moved out of the mixing material outlet 16, while the spraying of water by the cleaning nozzle 33 cleans the structure. The entire cleaning process is automated. After cleaning, the retraction of the electric telescopic rod 31 allows the gradient variable pitch flexible mixing screw structure 3 to be reinstalled into the second mixing chamber 13. The extension and retraction of the spring 34, combined with the rotation of the second bevel gear 29, allows the limiting hexagonal column 35 to automatically insert into the hexagonal slot 36, facilitating the installation of the gradient variable pitch flexible mixing screw structure 3.

[0051] IV. Material Adaptive Anti-agglomeration Intelligent Control System The material adaptive anti-agglomeration intelligent control system includes a material identification module, a database module, a parameter self-regulation module, and an online monitoring and feedback module.

[0052] The material identification module is located at the entrance of the powder feeding mechanism 8 and includes a near-infrared spectroscopy detection unit for automatically identifying the powder type, particle size distribution, filling ratio and surface activity parameters of the fed nano-metal powder.

[0053] The database module contains a massive database of nano-metal powder mixing processes, covering the optimal combination of process parameters for different types (silver powder, copper powder, nickel powder, etc.), different particle sizes (10nm~500nm), and different filling ratios (5wt%~60wt%) of nano-metal powders during the mixing process. This includes the ultrasonic power of the ultrasonic generator (100~1000W), the driving speed of the servo motor 20 (50~500rpm), the heating temperature of the electric heating plate 17 (150~350℃), and the output gas flow rate of the flow controller 11 (0.5~5L / min).

[0054] The parameter self-regulation module is electrically connected to the material identification module, the database module, the ultrasonic generator, the servo motor 20, the electric heating plate 17, and the flow controller 11. After the material identification module completes material identification, the parameter self-regulation module calls the matching data in the database module according to the identification result and automatically sets the initial values ​​of each core process parameter (the initial values ​​include the initial value of the ultrasonic power of the ultrasonic generator, the initial value of the drive speed of the servo motor 20, the initial value of the heating temperature of the electric heating plate 17, and the initial value of the output gas flow rate of the flow controller 11), without the need for manual adjustment.

[0055] The online monitoring and feedback module includes viscosity sensors, density sensors, and pressure sensors installed in the first mixing chamber 12 and the second mixing chamber 13, used to collect melt viscosity, powder dispersion density, and chamber pressure data in real time during the mixing process. These data are processed and transmitted to the parameter self-regulation module, which uses an adaptive control algorithm based on a neural network to dynamically correct the current process parameters. When an abnormal increase in melt viscosity is detected (which may indicate an increased tendency for powder agglomeration) or a decrease in dispersion density, the system automatically adjusts the ultrasonic power and the drive speed of the servo motor 20 to achieve early intervention and proactive anti-agglomeration, rather than passively breaking up existing agglomerates.

[0056] Workflow The working process of the device of this invention is as follows: S1: Nano-metal powder enters the sealed negative pressure feeding chamber 5 of the in-situ gas phase coating pretreatment integrated feeding mechanism 1 from the powder feeding mechanism 8, and is fluidized and dispersed in a negative pressure environment (-0.01 to -0.05 MPa).

[0057] S2: The gas phase coating unit 6 accurately atomizes and mixes inert carrier gas, gaseous coupling agent, and gaseous dispersant at a volume ratio of 100:1~5:0.5~2 and then introduces them into the closed negative pressure feed chamber 5 to perform single-layer gas phase coating treatment on the nano metal powder for 1~10 seconds (preferably 3 seconds) to form a dense ultrathin isolation coating film with a thickness of 1~5nm on the powder surface.

[0058] S3: The coated nano-metal powder is fed into the first mixing chamber 12 at a uniform speed through the micro-weight loss precision side feeding unit 7. At the same time, the plastic matrix (such as polyethylene, polypropylene, nylon, polycarbonate and other thermoplastic plastics) enters the first mixing chamber 12 through the plastic matrix inlet 15 and melts under the action of the electric heating plate 17, and merges with the fed nano-metal powder.

[0059] S4: The material identification module of the material adaptive anti-agglomeration intelligent control system automatically identifies the powder type, particle size distribution, filling ratio and surface activity parameters, and the parameter self-control module calls the database module to automatically set the initial process parameters.

[0060] S5: In the first mixing chamber 12, the distributed ultrasonic transducer assembly 14 applies a low-frequency ultrasonic field of 20-30kHz, using the cavitation effect to tear apart the agglomeration of nano-metal powder at the micro level; at the same time, the pulse stator-rotor assembly generates periodic pulse volume deformation, which generates intermittent extrusion, stretching and turbulence on the melt, realizing the synergistic anti-agglomeration mixing of ultrasonic field and pulse pressure field.

[0061] S6: The gradient variable pitch flexible mixing screw structure 3 sequentially completes the three-stage operation of "pre-dispersion, strong deagglomeration, and homogenization mixing": the feeding loosening section 21 pushes the material with a low compression ratio to avoid powder compression and agglomeration; the pulse shearing section 22 breaks up the residual agglomerates with high frequency and weak shearing; the homogenization plasticizing section 23 distributes the fully dispersed nano-metal powder in the plastic melt at the nanoscale, and finally outputs the mixed modified plastic melt continuously from the mixing material outlet 16 at the rear end of the second mixing chamber 13.

[0062] S7: The online monitoring and feedback module collects melt viscosity, powder dispersion density and cavity pressure data in real time during the mixing process. The parameter self-regulation module uses an adaptive control algorithm of neural network to dynamically correct process parameters and realize full-process adaptive intelligent regulation.

[0063] Industrial applicability The anti-agglomeration nano-metal powder modified plastic mixing production equipment of the present invention is suitable for the mixing and modification production of nano-metal powders such as silver powder, copper powder, and nickel powder with thermoplastic plastic matrices such as polyethylene, polypropylene, nylon, and polycarbonate. It can be widely used in the industrial production of high-performance conductive and thermally conductive modified plastics in the fields of electronics, aerospace, and new energy vehicles. The equipment of the present invention can realize continuous and intelligent production, and has good industrial application prospects and promotion value.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Any person skilled in the art can make modifications or alterations to the disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications or equivalent substitutions made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should be included within the protection scope of the present invention.

Claims

1. A production equipment for mixing and modifying plastics with anti-agglomeration nano-metal powder, characterized in that, The system includes, in sequence along the material flow direction: an in-situ gas phase coating pretreatment integrated feeding mechanism (1), an ultrasonic pulse pressure dual-field coupling anti-agglomeration mixing system (2), and a gradient variable pitch flexible mixing screw structure (3). The in-situ vapor phase coating pretreatment integrated feeding mechanism (1) includes a closed negative pressure feeding chamber (5), a vapor phase coating unit (6), and a micro-weight loss precision side feeding unit (7); the closed negative pressure feeding chamber (5) is a sealed chamber with a powder feeding mechanism (8) at its top, and the chamber maintains a negative pressure environment; the vapor phase coating unit (6) includes a gas mixer (9), an atomizing nozzle (10), and a flow controller (11). The ultrasonic pulse pressure dual-field coupling anti-agglomeration mixing system (2) includes a first mixing chamber (12), a second mixing chamber (13), a distributed ultrasonic transducer assembly (14), and a pulse stator-rotor assembly; the first mixing chamber (12) and the second mixing chamber (13) are both closed cylindrical cavities and are interconnected. The front end of the first mixing chamber (12) is provided with a plastic matrix inlet (15) and a nano-metal powder inlet. The nano-metal powder inlet is connected to the outlet of the micro-weight loss precision side feeding unit (7). The rear end of the second mixing chamber (13) is provided with a mixing material outlet (16), and electric heating plates (17) are provided in the walls of both the first mixing chamber (12) and the second mixing chamber (13); the distributed ultrasonic transducer assembly (14) includes multiple ultrasonic transducers and ultrasonic generators distributed along the axial and circumferential directions of the first mixing chamber (12), each ultrasonic transducer is fixedly installed on the outer wall of the first mixing chamber (12), and each ultrasonic transducer is driven by the ultrasonic generator and its start / stop and power are independently controlled; The gradient variable pitch flexible mixing screw structure (3) is rotatably set inside the second mixing chamber (13) through a transmission mechanism, and includes a feeding loosening section (21), a pulse shearing section (22) and a homogenizing plasticizing section (23) in sequence along the material flow direction; the feeding loosening section (21) adopts a large pitch structure; the pulse shearing section (22) adopts a staggered asymmetric kneading blocks (24) and micro pulse grooves (25) structure, each of the kneading blocks (24) is asymmetrically arranged in the screw axis, and the micro pulse grooves (25) are set on the screw surface between the kneading blocks (24) and form a periodic groove structure; the homogenizing plasticizing section (23) adopts a small pitch structure.

2. The anti-agglomeration nano-metal powder modified plastic compounding production equipment according to claim 1, characterized in that: The inlet end of the gas mixer (9) is connected to the inert gas source, coupling agent source and dispersant source through pipes respectively. The outlet end of the gas mixer (9) is provided with the atomizing nozzle (10). The atomizing nozzle (10) is fixedly installed on the inner wall of the sealed negative pressure feeding chamber (5). The flow controller (11) is set on the pipe. The micro-weight loss precision side feeding unit (7) is set at the outlet of the gas phase coating unit (6). Its input end is connected to the outlet end of the gas phase coating unit (6). The micro-weight loss precision side feeding unit (7) has a built-in feeding screw driven by a drive motor and a micro-weight loss metering module. The micro-weight loss metering module is electrically connected to the drive motor.

3. The anti-agglomeration nano-metal powder modified plastic mixing production equipment according to claim 1, characterized in that: The negative pressure environment inside the sealed negative pressure feed chamber (5) is -0.01 to -0.05 MPa. The inert carrier gas output from the inert gas source, the gaseous coupling agent output from the coupling agent source, and the gaseous dispersant output from the dispersant source are mixed in the gas mixer (9) at a volume ratio of 100:1 to 5:0.5 to 2, and then atomized and sprayed into the sealed negative pressure feed chamber (5) through the atomizing nozzle (10).

4. The anti-agglomeration nano-metal powder modified plastic mixing production equipment according to claim 1, characterized in that: The pulse stator-rotor assembly includes a stator (18) fixedly disposed on the inner wall of the first mixing chamber (12), a rotor (19) rotatably disposed inside the first mixing chamber (12), and a servo motor (20) for driving the rotor (19) to rotate. The inner surface of the stator (18) is provided with periodic protrusions, and the outer surface of the rotor (19) is provided with periodic grooves. A pulse deformation gap is formed between the protrusions and the grooves.

5. The anti-agglomeration nano-metal powder modified plastic compounding production equipment according to claim 1, characterized in that: The pitch of the feed loosening section (21) is 1.5 to 3 times that of the pitch of the homogenization plasticizing section (23); the entire surface of the screw is provided with a nano-ceramic passivation modification layer.

6. The anti-agglomeration nano-metal powder modified plastic mixing production equipment according to claim 1, characterized in that: The transmission mechanism includes a side support plate, a transmission rod (26), a chain gear transmission assembly (27), a first bevel gear (28), and a second bevel gear (29); the side support plate is fixedly connected to the outside of the first mixing chamber (12); the transmission rod (26) is rotatably connected to the surface of the side support plate, the upper end of the transmission rod (26) is connected to the servo motor (20) through the chain gear transmission assembly (27), and the lower end of the transmission rod (26) is fixedly connected to the first bevel gear (28); the second bevel gear (29) is rotatably connected to the outside of the second mixing chamber (13), and the first bevel gear (28) and the second bevel gear (29) mesh and transmit power; the second bevel gear (29) is connected to the end of the gradient variable pitch flexible mixing screw structure (3).

7. The anti-agglomeration nano-metal powder modified plastic compounding production equipment according to claim 6, characterized in that: A screw cleaning mechanism (4) is provided on the outside of the second mixing chamber (13). The screw cleaning mechanism (4) includes an electric telescopic rod (31), a U-shaped rod (32), a cleaning nozzle (33), a spring (34), a limiting hexagonal column (35), and a hexagonal groove (36). The cleaning nozzle (33) is directly opposite the mixing material outlet (16). The electric telescopic rod (31) is fixedly installed on the outside of the second mixing chamber (13). One end of the U-shaped rod (32) is fixedly connected to the telescopic end of the electric telescopic rod (31). The other end of the 32) is rotatably connected to the end of the gradient variable pitch flexible mixing screw structure (3); the gradient variable pitch flexible mixing screw structure (3) is provided with the hexagonal groove (36) at the end away from the U-shaped rod (32); the rotating end of the second bevel gear (29) is provided with a cavity, the limiting hexagonal column (35) is slidably connected in the cavity, the spring (34) is fixedly connected between the limiting hexagonal column (35) and the inner wall of the cavity, and the limiting hexagonal column (35) can fit and engage with the hexagonal groove (36).

8. The anti-agglomeration nano-metal powder modified plastic compounding production equipment according to claim 7, characterized in that: The end of the limiting hexagonal prism (35) is chamfered (30).

9. The anti-agglomeration nano-metal powder modified plastic mixing production equipment according to claim 1, characterized in that: It also includes a material adaptive anti-agglomeration intelligent control system, which includes a material identification module, a database module, a parameter self-regulation module and an online monitoring feedback module; the material identification module is set at the entrance of the powder feeding mechanism (8) and includes a near-infrared spectroscopy detection unit; the database module has a built-in database of nano-metal powder mixing process; the parameter self-regulation module is electrically connected to the material identification module, the database module, the ultrasonic generator, the servo motor (20), the electric heating plate (17) and the flow controller (11) respectively; the online monitoring feedback module includes a viscosity sensor, a density sensor and a pressure sensor set in the first mixing chamber (12) and the second mixing chamber (13), and the online monitoring feedback module is electrically connected to the parameter self-regulation module.

10. The anti-agglomeration nano-metal powder modified plastic compounding production equipment according to claim 9, characterized in that: The built-in process database of the database module covers the optimal combination of process parameters for different types, particle sizes and filling ratios of nano-metal powders during the mixing process. The process parameters include the ultrasonic power of the ultrasonic generator, the driving speed of the servo motor (20), the heating temperature of the electric heating plate (17) and the output gas flow rate of the flow controller (11). The parameter self-regulation module calls the matching data in the database module according to the identification result of the material identification module, automatically sets the initial value of each core process parameter, and uses the adaptive control algorithm of the neural network to dynamically correct the current process parameters.

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