A high-viscosity polyurethane two-component active mixing foaming system based on magneto-rheological regulation and a control method thereof

Abstract

This invention relates to the field of polyurethane foaming equipment technology, and provides a high-viscosity polyurethane two-component active mixing foaming system and its control method based on magnetorheological regulation. The system includes a magnetorheological polyol supply unit, an isocyanate supply unit, a proportional control unit, an active mixing unit, a magnetic field generating unit, and a controller. The active mixing unit is configured in conjunction with an electromagnetic coil array. The controller controls the electromagnetic coil array to generate a dynamically changing magnetic field to drive magnetic nanoparticles in the polyol component to move within the mixing chamber, achieving active mixing of the high-viscosity two-component system. The proportional control unit is used to detect and adjust the flow rates of the polyol and isocyanate components. The control method includes steps such as material conveying, proportional control, magnetic field regulation, and mixing output. This invention improves the mixing uniformity of the high-viscosity system and helps reduce wall adhesion by driving the movement of magnetic nanoparticles through a magnetic field.

Description

Technical Field

[0001] This invention relates to the field of polyurethane foaming equipment technology, and in particular to a high-viscosity polyurethane two-component active mixing foaming system based on magnetorheological regulation and its control method. Background Technology

[0002] Polyurethane foam materials are widely used in furniture, automobiles, building insulation, packaging, and composite materials. Their preparation typically involves mixing polyol and isocyanate components in a specific ratio and then reacting to form foam. The metering accuracy, mixing uniformity, and conveying stability of the two-component materials have a significant impact on the cell structure, mechanical properties, and molding quality of the foam products.

[0003] As polyurethane materials develop towards higher filler content, higher flame retardancy, and higher performance, polyol components typically incorporate more fillers, flame retardants, or functional additives, leading to a significant increase in system viscosity. High-viscosity two-component systems exhibit poor flowability during transport and mixing, easily forming a laminar flow state within the mixing chamber. This results in low material exchange efficiency between components, making it difficult to achieve thorough and uniform mixing in a short time.

[0004] In existing technologies, polyurethane two-component mixing equipment mostly uses static mixing, mechanical stirring, or impact mixing to achieve component mixing. These methods can meet certain requirements when processing low to medium viscosity systems, but for high viscosity polyurethane two-component systems, they often suffer from low mixing efficiency and poor mixing uniformity, which can easily lead to incomplete local reactions, uneven cell structure, and fluctuations in product performance.

[0005] Furthermore, high-viscosity materials tend to adhere to the inner walls of the mixing chamber and the surface of the flow channels during the mixing process, forming residues and dead zones. This not only affects the continuous and stable mixing of subsequent materials but may also cause problems such as flow channel blockage, poor material discharge, difficult cleaning, and increased maintenance costs. In particular, polyurethane two-component systems react rapidly after mixing, requiring high mixing time and quality. If uniform mixing cannot be achieved in a short time, it can easily lead to unstable foaming and affect the quality of the final product.

[0006] Therefore, how to provide a mixing and foaming system and its control method suitable for high-viscosity polyurethane two-component systems, so as to improve mixing efficiency and mixing uniformity, reduce wall adhesion and residue problems, and improve system operation stability, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control, so as to solve the problems of low mixing efficiency, poor mixing uniformity and easy wall adhesion in the mixing process of high-viscosity polyurethane two-component systems in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: In one possible implementation, a high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological regulation is provided, comprising: A magnetorheological polyol supply unit is used to transport polyol components containing magnetic nanoparticles. Isocyanate supply unit for conveying isocyanate components; A proportional control unit is used to control the output ratio between the magnetorheological polyol supply unit and the isocyanate supply unit; An active mixing unit has its inlet connected to the outlets of the magnetorheological polyol supply unit and the isocyanate supply unit, respectively. The magnetic field generating unit includes an array of electromagnetic coils surrounding the active mixing unit; The controller is electrically connected to both the proportional control unit and the magnetic field generating unit. The controller is configured to: control the electromagnetic coil array to generate a dynamically changing magnetic field according to a preset mixing program, drive the magnetic nanoparticles in the polyol component to move along a preset trajectory inside the active mixing unit, so as to achieve active stirring and mixing of the fluid in the mixing chamber.

[0009] In one possible implementation, the magnetorheological polyol supply unit includes a constant temperature control device and a volumetric delivery pump. The constant temperature control device includes a temperature sensor and a heating element for heating the polyol component to 40°C to 60°C. The isocyanate supply unit includes a precision metering pump driven by a variable frequency motor; The proportional control unit includes a first mass flow meter located at the outlet of the magnetorheological polyol supply unit and a second mass flow meter located at the outlet of the isocyanate supply unit. The controller is electrically connected to the first mass flow meter, the second mass flow meter, the volumetric pump, and the variable frequency motor.

[0010] In one possible implementation, the magnetic nanoparticles in the polyol component have a particle size of 10 nm to 100 nm and a mass percentage of 0.5% to 3.0%, and the surface of the magnetic nanoparticles is coated with a coupling agent layer. The magnetic nanoparticles are selected from one or more of the following: iron(II,III) oxide, γ-ferric oxide, nickel-iron alloy, and cobalt-iron alloy. The coupling agent is selected from one or more of silane coupling agents, titanate coupling agents, and aluminate coupling agents.

[0011] In one possible implementation, the electromagnetic coil array includes a plurality of independent excitation coils arranged sequentially along the axial direction of the active mixing unit, each excitation coil being controlled by an independent drive circuit.

[0012] In one possible implementation, the active mixing unit includes: a mixing chamber with an anti-stick coating on its inner wall surface; a premixing structure disposed at the inlet end of the mixing chamber; and a plurality of flow guiding elements disposed within the mixing chamber. The flow guiding element is made of a non-magnetic material and has a microgroove structure on its surface.

[0013] In one possible implementation, the controller is configured to execute at least one of the following control modes: rotating magnetic field mode, traveling wave magnetic field mode, oscillating magnetic field mode, and composite magnetic field mode. The system also includes a magnetic field strength sensor for real-time monitoring of the magnetic field strength distribution within the mixing chamber, and the controller dynamically adjusts the current of each excitation coil based on the feedback signal from the magnetic field strength sensor.

[0014] In one possible implementation, a control method for a high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological regulation is provided, comprising the following steps: Step S1: Mix the polyol component with surface-modified magnetic nanoparticles to obtain a magnetorheological polyol component with magnetorheological properties. Step S2: The magnetorheological polyol component and the isocyanate component are delivered to the active mixing unit in a set ratio; Step S3: The controller acquires the flow rates of the magnetorheological polyol component and the isocyanate component in real time and dynamically adjusts the delivery ratio to maintain it within the target range. Step S4: The controller controls the electromagnetic coil array to generate a dynamically changing magnetic field, driving the magnetic nanoparticles in the magnetorheological polyol component to move in the mixing chamber, so that the magnetorheological polyol component and the isocyanate component are mixed. Step S5: Discharge the mixed material.

[0015] In one possible implementation, in step S4, the dynamically changing magnetic field includes a rotating magnetic field, a traveling wave magnetic field, an oscillating magnetic field, or a composite magnetic field, with a magnetic field strength of 0.1 T to 1.0 T and a magnetic field change frequency of 10 Hz to 500 Hz.

[0016] In one possible implementation, an anti-adhesion control step is also included: the controller controls the electromagnetic coil array to generate a pulsed magnetic field, driving the magnetic nanoparticles to move toward the central region of the mixing chamber, thereby peeling off the material adhering to the chamber wall.

[0017] In one possible implementation, an application of a magnetorheologically controlled high-viscosity polyurethane two-component active mixing foaming system is provided, wherein the system described in any one of claims 1 to 6 is used to prepare high-filled flame-retardant polyurethane foam, high-viscosity polyurethane composite material or high-performance reaction injection molded article.

[0018] Based on the above technical solution, the high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control provided by the present invention is configured with a magnetorheological polyol supply unit, an isocyanate supply unit, a proportioning control unit, an active mixing unit, a magnetic field generating unit, and a controller. The controller controls an electromagnetic coil array to generate a dynamically changing magnetic field according to a preset mixing program, which drives the magnetic nanoparticles in the polyol component to move along a preset trajectory inside the active mixing unit, thereby achieving active stirring and mixing of the fluid in the mixing chamber. This transforms the traditional mixing method that relies on mechanical shearing or passive fluid disturbance into a controlled active mixing method, which is beneficial to enhance the material exchange and flow coupling between the high-viscosity polyol component and the isocyanate component, reduce the mixing dead zone, and improve the mixing efficiency, mixing uniformity, and reaction consistency of the two-component system.

[0019] Meanwhile, the proportional control unit can detect and dynamically adjust the delivery ratio of magnetorheological polyol components and isocyanate components in real time, which helps to improve the system's metering accuracy and process controllability, and reduce the risk of uneven cell structure, abnormal local curing, or product performance fluctuations caused by ratio fluctuations.

[0020] Furthermore, by setting up multiple independent excitation coils and combining control modes of rotating magnetic field, traveling wave magnetic field, oscillating magnetic field or composite magnetic field, the magnetic field action mode can be flexibly adjusted according to different material viscosities, flow states and mixing stages, thereby improving the system's adaptability to complex working conditions. In addition, by setting up a premixing structure, flow guiding element and anti-stick coating in the mixing chamber, and combining it with pulsed magnetic field to peel off the material adhering to the chamber wall, it is beneficial to reduce the wall adhesion phenomenon, improve the material discharge effect, reduce the difficulty of equipment cleaning and maintenance, and improve the stability of continuous operation.

[0021] Therefore, this invention can effectively solve the technical problems of low mixing efficiency, poor mixing uniformity, easy adhesion to the wall and insufficient local reaction of high viscosity polyurethane two-component under traditional mixing methods. It can be applied to the preparation of high-filled flame-retardant polyurethane foam, high viscosity polyurethane composite materials and high-performance reaction injection molded products, and has good engineering application value and promotion prospects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control, provided in an embodiment of the present invention. Figure 2 A cross-sectional structural diagram of the active mixing unit and the magnetic field generating unit provided in an embodiment of the present invention; Figure 3 A logic block diagram of a proportional control unit provided in an embodiment of the present invention. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the scope of protection of the present invention.

[0024] It should be noted that, where there is no conflict, the technical features in the various embodiments of the present invention can be combined with each other. Those skilled in the art, after reading this specification, can make various improvements or modifications to the present invention without departing from its spirit and essence, and such improvements or modifications should also fall within the protection scope of the present invention.

[0025] Furthermore, for ease of explanation, the relevant structures or steps are described in a simplified manner in this specification. For parts not described in detail, conventional technical means in this field can be used for implementation.

[0026] I. Overall Structure Description In one embodiment, such as Figure 1 As shown, the high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control provided by the present invention includes a magnetorheological polyol supply unit, an isocyanate supply unit, a proportioning control unit, an active mixing unit, a magnetic field generating unit, and a controller.

[0027] The magnetorheological polyol supply unit is used to store and transport polyol components containing magnetic nanoparticles, and the isocyanate supply unit is used to store and transport isocyanate components. The magnetorheological polyol supply unit and the isocyanate supply unit are respectively connected to the inlet end of the active mixing unit through their respective transport pipelines, so as to continuously transport the two components into the active mixing unit for mixing.

[0028] The proportional control unit is located on the delivery path of the magnetorheological polyol supply unit and the isocyanate supply unit, and is used to detect and adjust the output flow of the two components, so that the magnetorheological polyol component and the isocyanate component enter the active mixing unit in a preset ratio.

[0029] The active mixing unit is used to contain the two components and form a mixing space. Its inlet is connected to the magnetorheological polyol supply unit and the isocyanate supply unit, and its outlet is used to output the mixed material to the subsequent foaming or molding process.

[0030] The magnetic field generating unit is located outside the active mixing unit and is spatially arranged corresponding to the active mixing unit, and is used to form an adjustable magnetic field environment inside the active mixing unit.

[0031] The controller is electrically connected to both the proportional control unit and the magnetic field generating unit, and is used to receive flow detection signals and output control signals. On the one hand, the controller adjusts the conveying device according to the detected flow information of each component to achieve proportional control; on the other hand, the controller controls the magnetic field generating unit to generate a dynamically changing magnetic field according to a preset mixing program, so that the magnetic nanoparticles in the magnetorheological polyol component undergo controlled movement inside the active mixing unit, thereby causing disturbance in the surrounding fluid and realizing active mixing of the high-viscosity two-component system.

[0032] In the above structure, the units cooperate with each other: the supply unit is responsible for material conveying, the proportion control unit is responsible for proportion adjustment, the active mixing unit provides mixing space, the magnetic field generating unit provides external field effect, and the controller realizes overall coordinated control, thus forming an active mixing foaming system suitable for high viscosity polyurethane two-component systems.

[0033] II. Supply and Proportion Control System (corresponding to) Figure 1 + Figure 3 ) In one embodiment, such as Figure 1 As shown, the magnetorheological polyol supply unit is used to store and transport polyol components containing magnetic nanoparticles. Specifically, the magnetorheological polyol supply unit includes a storage container, a constant temperature control device, and a volumetric transfer pump. The storage container is used to store pre-prepared magnetorheological polyol components; the constant temperature control device is used to regulate the temperature of the polyol components in the storage container, maintaining it within a preset temperature range to improve its flowability and ensure transport stability; the volumetric transfer pump is connected to the storage container and is used to transport the magnetorheological polyol components to the active mixing unit at a stable flow rate.

[0034] Preferably, the constant temperature control device includes a temperature sensor and a heating element. The temperature sensor is used to detect the temperature of the polyol component in real time, and the heating element heats the polyol component according to the detection signal to keep its temperature within the range of 40℃ to 60℃, thereby reducing the viscosity of the system and improving the conveying and subsequent mixing effect.

[0035] In one embodiment, the isocyanate supply unit is used to store and deliver isocyanate components, and its structure includes a storage container and a precision metering pump driven by a variable frequency motor. The precision metering pump can adjust the output flow rate according to a control signal to achieve accurate metering and delivery of the isocyanate components, and cooperates with the magnetorheological polyol supply unit in terms of flow control.

[0036] like Figure 3 As shown, the proportional control unit includes a first mass flow meter and a second mass flow meter, which are respectively installed in the delivery pipelines of the magnetorheological polyol component and the isocyanate component, for detecting the real-time flow rates of the two components. The first mass flow meter is used to detect the flow rate of the magnetorheological polyol component, and the second mass flow meter is used to detect the flow rate of the isocyanate component.

[0037] The controller is electrically connected to the first mass flow meter, the second mass flow meter, the volumetric pump, and the variable frequency motor, respectively, and is used to receive flow detection signals and output adjustment commands. Specifically, the controller dynamically adjusts the output of the volumetric pump and the speed of the variable frequency motor based on the deviation between the detected flow values ​​of the two components and the preset ratio, so as to maintain the flow ratio of the magnetorheological polyol component to the isocyanate component within the target range.

[0038] In one embodiment, the controller employs a closed-loop control strategy to adjust the delivery ratio of the magnetorheological polyol component and the isocyanate component. Specifically, the controller acquires the detection signals from the first and second mass flow meters with a sampling period of 100 ms to 500 ms, and performs calculations based on the deviation between the detected real-time flow value and the preset ratio.

[0039] In one embodiment, the controller dynamically adjusts the output flow rate of the positive displacement pump and the speed of the variable frequency motor based on a proportional-integral-derivative (PID) control algorithm, thereby achieving precise control of the two component flow rates. Through this control method, the system can quickly recover to the target mix ratio when flow rates fluctuate or operating conditions change.

[0040] Preferably, the control accuracy of the proportional control unit can be controlled within ±1%, and more preferably within ±0.8%, thereby improving the metering accuracy and mixing stability of the two-component system.

[0041] In the above control process, the proportional control unit and the controller form a closed-loop control system. Through real-time detection and feedback adjustment, the metering accuracy and proportioning stability of the two-component system are improved, and uneven mixing or abnormal reaction caused by flow fluctuations are avoided.

[0042] Furthermore, the proportional control system can set different proportioning parameters according to different process requirements and make dynamic corrections during operation, thereby adapting to different formulation systems and operating conditions, and improving the system's adaptability and control flexibility.

[0043] III. Magnetorheological Polyol Components (Material System Description) In one embodiment, the magnetorheological polyol component is a composite system in which magnetic nanoparticles are dispersed in a polyol matrix, so that the polyol component has magnetorheological properties under the action of an external magnetic field.

[0044] Specifically, the polyol component can be selected from polyether polyols, polyester polyols, or combinations thereof, preferably conventional industrial polyol raw materials suitable for polyurethane foaming systems. To impart magnetic responsiveness, magnetic nanoparticles are added to the polyol component and dispersed uniformly within the polyol matrix using a dispersion process.

[0045] In one embodiment, the magnetic nanoparticles have a particle size of 10 nm to 100 nm, preferably 20 nm to 80 nm, and a mass percentage of 0.5% to 3.0%. Within this particle size and content range, the system can be guaranteed to have good magnetic response characteristics, while avoiding the impact of particle agglomeration on the system's rheological properties and stability.

[0046] In one embodiment, the magnetic nanoparticles are selected from one or more of iron(III) oxide, γ-ferric oxide, nickel-iron alloy, or cobalt-iron alloy. Among them, iron(III) oxide has good magnetic response performance and chemical stability, making it suitable for most application scenarios.

[0047] To improve the dispersion stability of magnetic nanoparticles in a polyol system, the surface of the magnetic nanoparticles is preferably coated with a coupling agent layer. The coupling agent can be selected from one or more of silane coupling agents, titanate coupling agents, or aluminate coupling agents. By modifying the particle surface, the interfacial compatibility between the nanoparticles and the polyol matrix can be enhanced, the tendency of particle aggregation can be reduced, thereby improving the long-term stability and uniformity of the system.

[0048] In one embodiment, the magnetorheological polyol component can be prepared by adding magnetic nanoparticles and the polyol component in a predetermined ratio to a mixing container, and then treating the mixture by mechanical stirring, ultrasonic dispersion, or high-shear dispersion to form a stable dispersion system of the magnetic nanoparticles in the polyol. If necessary, a dispersant can be added to further improve the dispersion effect.

[0049] In the aforementioned material system, magnetic nanoparticles exhibit a random distribution in the absence of a magnetic field, but under the influence of an applied magnetic field, they align or form chain-like structures, thereby altering the local rheological properties of the fluid and macroscopically demonstrating a controllable ability to regulate the fluid flow state. Utilizing this property, during active mixing, the movement of magnetic nanoparticles can be driven by a magnetic field, thereby causing disturbances in the surrounding fluid and achieving enhanced mixing of high-viscosity systems.

[0050] Furthermore, by adjusting the particle size, content, and surface modification method of magnetic nanoparticles, the rheological properties and magnetic response characteristics of magnetorheological polyol components can be controlled, thereby adapting to the polyurethane foaming requirements of different viscosity grades and different process conditions.

[0051] IV. Active Hybrid Unit Structure (corresponding to) Figure 2 ) In one embodiment, such as Figure 2 As shown, the active mixing unit includes a mixing chamber for accommodating the magnetorheological polyol component and the isocyanate component, and providing space for the two to undergo a mixing reaction.

[0052] The mixing chamber has an inlet end and an outlet end. The inlet end is connected to the delivery pipelines of the magnetorheological polyol supply unit and the isocyanate supply unit, respectively, for introducing the two components. The outlet end is used to output the mixed material to the subsequent foaming or molding process. The mixing chamber can be cylindrical or nearly cylindrical in shape to facilitate the surrounding arrangement of the external electromagnetic coil array.

[0053] In one embodiment, the inlet end of the mixing chamber is provided with a premixing structure for preliminary mixing of the two components entering the mixing chamber. The premixing structure may be a jet-type structure, a staggered flow channel structure, or a guide plate structure, so that the two components initially converge and disperse before entering the main mixing region, thereby creating conditions for subsequent enhanced mixing.

[0054] In one embodiment, the mixing chamber is provided with multiple flow guiding elements, which are arranged at intervals along the fluid flow direction to change the fluid flow path and enhance fluid turbulence. By providing flow guiding elements, the fluid can be split, converge, and partially rotated within the mixing chamber, thereby increasing the contact interface between different components and improving mixing efficiency.

[0055] Preferably, the flow guiding element is made of a non-magnetic material to avoid interfering with the magnetic field distribution. Furthermore, the surface of the flow guiding element has a microgroove structure, which can generate localized microscale disturbances when fluid passes through, thereby enhancing shearing and dispersion effects and improving the mixing uniformity of the high-viscosity system.

[0056] In one embodiment, the inner wall surface of the mixing chamber is provided with an anti-stick coating. The anti-stick coating may be made of a material with low surface energy to reduce the adhesion of materials to the chamber wall surface, thereby reducing material residue and wall sticking, improving material discharge efficiency and reducing cleaning difficulty.

[0057] In the above structure, the premixed structure, the flow guiding element, and the anti-stick coating work together: the premixed structure is used to achieve initial dispersion, the flow guiding element is used to enhance flow disturbance and mixing process, and the anti-stick coating is used to reduce material adhesion and residue, thereby jointly creating a mixing environment suitable for high viscosity polyurethane two-component systems.

[0058] In addition, the structural design of the active mixing unit must be matched with the external magnetic field generating unit so that the fluid in the mixing chamber can generate an effective response under the action of the magnetic field, thereby further enhancing the mixing process.

[0059] V. Magnetic Field Generating Unit (corresponding to) Figure 2 ) In one embodiment, such as Figure 2 As shown, the magnetic field generating unit is disposed outside the active mixing unit and arranged around the outer periphery of the mixing cavity, for forming a spatially controllable magnetic field inside the mixing cavity.

[0060] Specifically, the magnetic field generating unit includes an electromagnetic coil array, which is arranged sequentially along the axial direction of the active mixing unit and includes multiple independently configured excitation coils. Each excitation coil is connected to a corresponding drive circuit, thereby enabling independent control of the energizing state, current magnitude, and energizing sequence of each excitation coil.

[0061] In one embodiment, each excitation coil can be uniformly distributed around the periphery of the mixing cavity, or it can be non-uniformly arranged according to the functional requirements of the mixing area, so as to achieve differentiated control of the magnetic field strength and distribution in different areas.

[0062] By adjusting the current amplitude, on / off state, and phase relationship of each excitation coil, various forms of magnetic field distribution can be formed inside the hybrid cavity, including but not limited to radially distributed magnetic fields, axially varying gradient magnetic fields, and time-varying dynamic magnetic fields.

[0063] In one embodiment, the magnetic field generating unit, under the control of the controller, can generate a rotating magnetic field, a traveling wave magnetic field, an oscillating magnetic field, or a composite magnetic field. The rotating magnetic field is formed by applying an alternating current with a phase difference between adjacent excitation coils, causing the magnetic field to rotate circumferentially within the mixing cavity; the traveling wave magnetic field is formed by sequentially exciting each excitation coil along the axial direction, causing the magnetic field to propagate along the axial direction of the mixing cavity; the oscillating magnetic field is achieved by periodically changing the direction of the magnetic field; and the composite magnetic field is a superposition or combination of the above-mentioned magnetic field forms.

[0064] In one embodiment, the magnetic field generating unit can also be used in conjunction with a magnetic field strength sensor, which is used to detect the magnetic field distribution within the mixing cavity. The controller adjusts the current of each excitation coil in real time based on the detection signal, thereby achieving closed-loop control of the magnetic field and making the magnetic field distribution more stable and precise.

[0065] In the above structure, the electromagnetic coil array and the active mixing unit are spatially coupled, allowing the magnetic field to directly act on the magnetorheological polyol components inside the mixing chamber. Precise control of the spatial distribution and temporal variation of the magnetic field provides an external driving force for the controlled movement of magnetic nanoparticles, thus providing the fundamental conditions for achieving active mixing of high-viscosity systems.

[0066] Furthermore, the structure, number of coils, and arrangement of the electromagnetic coil array can be adjusted according to the size of the mixing cavity and process requirements to adapt to different specifications of the mixing system.

[0067] VI. Magnetorheological Active Mixing Mechanism In one embodiment, the present invention utilizes the response characteristics of magnetic nanoparticles in magnetorheological polyol components to an applied magnetic field to achieve active mixing of a high-viscosity two-component system.

[0068] Specifically, in the absence of an external magnetic field, the magnetic nanoparticles are randomly distributed in the polyol matrix, and the overall system behaves as a conventional high-viscosity fluid. Its internal flow mainly depends on the fluid motion generated by macroscopic transport, and the mixing process is limited by molecular diffusion and local shearing under laminar flow conditions, resulting in low mixing efficiency.

[0069] When the magnetic field generating unit produces an external magnetic field, the magnetic nanoparticles undergo directional alignment, chain-like structure formation, or migration along the magnetic field direction under the influence of the magnetic field force, thereby exerting a traction effect on the surrounding fluid. As the spatial distribution and time change of the magnetic field, the magnetic nanoparticles generate continuous or periodic motion trajectories within the mixing cavity, which in turn causes localized flow and disturbance in the surrounding polyol matrix.

[0070] In one embodiment, when a rotating magnetic field is applied, the magnetic nanoparticles move circumferentially within the mixing cavity, causing the fluid to form a rotating flow structure, thereby enhancing radial and circumferential material exchange; when a traveling wave magnetic field is applied, the magnetic nanoparticles migrate axially along the mixing cavity, driving the fluid to form axial transport and convection circulation, which is beneficial for eliminating axial concentration gradients; when an oscillating magnetic field is applied, the magnetic nanoparticles undergo reciprocating motion in local areas, thereby enhancing microscale disturbance and local shearing; when a composite magnetic field mode is used, multi-directional and multi-scale fluid disturbance can be achieved simultaneously in the same mixing process.

[0071] Through the aforementioned magnetic field, magnetic nanoparticles are equivalent to forming "controllable micro-drive units" inside high-viscosity fluids. Their movement can break the fluid stratification structure under laminar flow conditions, significantly enhance convection and mixing within the fluid, thereby increasing the contact frequency and interface renewal rate between components.

[0072] Furthermore, with the assistance of the flow guiding element and the premixing structure, the flow driven by magnetic nanoparticles and the structural disturbances are superimposed, forming a multi-scale coupled flow field in the mixing cavity, including macroscopic flow, local vortices and microscale disturbances, thereby further improving the mixing uniformity.

[0073] Furthermore, during the anti-adhesion control process, by applying a specific pulsed magnetic field, magnetic nanoparticles near the cavity wall region can be driven to migrate towards the center of the mixing cavity, thereby causing the material attached to the cavity wall surface to detach and suppress the wall adhesion phenomenon.

[0074] Compared with traditional mixing methods that rely on mechanical stirring or passive fluid disturbance, this invention uses magnetic nanoparticles driven by a magnetic field to achieve active control of the fluid interior. This makes the mixing process no longer dependent on external flow conditions, but achieves efficient mixing through an internal driving mechanism, making it particularly suitable for high viscosity, laminar flow, and difficult-to-mix systems.

[0075] Therefore, by combining magnetorheological effect with dynamic magnetic field control, the present invention can achieve uniform mixing of high viscosity polyurethane two-component system in a short time, thereby improving the stability of foaming process and the consistency of product performance.

[0076] VII. Magnetic field control mode (corresponding to) Figure 2 ) In one embodiment, the controller controls the energizing mode of the electromagnetic coil array, enabling the formation of different dynamic magnetic fields within the active mixing unit, thereby regulating the motion state of the magnetic nanoparticles. Specifically, the controller can select and execute one or more magnetic field control modes according to a preset mixing program.

[0077] In one embodiment, the magnetic field control mode includes a rotating magnetic field mode. In this mode, the controller applies alternating currents with a phase difference to multiple excitation coils distributed circumferentially along the mixing cavity, causing the resulting magnetic field to rotate within the cross-section of the mixing cavity. Consequently, the magnetic nanoparticles move continuously circumferentially under the influence of the magnetic field, driving the fluid to form a rotating flow structure, thereby enhancing the mixing effect in both the radial and circumferential directions.

[0078] In one embodiment, the magnetic field control mode includes a traveling wave magnetic field mode. In this mode, the controller sequentially excites multiple excitation coils arranged along the axial direction of the mixing cavity according to a predetermined timing sequence, causing the magnetic field to propagate in a traveling wave form along the axial direction. Driven by the traveling wave magnetic field, the magnetic nanoparticles migrate along the axial direction, thereby driving the fluid to generate axial transport and circulation flow, which is beneficial to improving the mixing uniformity along the flow direction.

[0079] In one embodiment, the magnetic field control mode includes an oscillating magnetic field mode. In this mode, the controller periodically changes the energizing direction or current magnitude of the excitation coil, causing the magnetic field direction or intensity to alternate within a certain frequency range. Magnetic nanoparticles undergo reciprocating motion under the influence of this magnetic field, thereby enhancing local disturbances and shearing effects, and improving the dispersion effect at the microscale.

[0080] In one embodiment, the magnetic field control mode includes a composite magnetic field mode. This mode is a combination of two or more of the aforementioned rotating magnetic field, traveling wave magnetic field, and oscillating magnetic field. By superimposing or alternating different magnetic field modes, a more complex flow structure can be formed within the mixing cavity, achieving multi-directional and multi-scale coupled mixing, thereby further improving mixing efficiency and uniformity.

[0081] In one embodiment, the controller can dynamically switch or adjust the magnetic field mode based on the material viscosity, flow conditions, and different mixing stages. For example, a traveling wave magnetic field can be used in the early stage of mixing to promote rapid material transport, a rotating magnetic field can be used in the middle stage to enhance overall mixing, and an oscillating magnetic field can be used in the later stage to enhance local dispersion, thereby achieving optimized control throughout the entire process.

[0082] In addition, the controller can also adjust the magnetic field strength and the frequency of change, wherein the magnetic field strength can be set in the range of 0.1 T to 1.0 T, and the magnetic field frequency of change can be set in the range of 10 Hz to 500 Hz, so as to adapt to the mixed requirements under different working conditions.

[0083] By using the above-mentioned magnetic field control mode and parameter adjustment method, the movement of magnetic nanoparticles in the mixing cavity becomes more controllable, thereby achieving precise control over the mixing process of the high-viscosity polyurethane two-component system.

[0084] VIII. Magnetic Field Feedback Control In one embodiment, to further improve the accuracy of magnetic field control and the stability of the mixing process, the system also includes a magnetic field strength sensor for real-time monitoring of the magnetic field distribution inside the active mixing unit, thereby constructing a closed-loop magnetic field control system.

[0085] Specifically, the magnetic field strength sensor is located near the active mixing unit, preferably on the outer wall of the mixing chamber or embedded near the mixing region, for detecting the magnetic field strength information inside the mixing chamber or in its vicinity. The magnetic field strength sensor can be a Hall sensor, a magnetoresistive sensor, or other devices capable of magnetic field detection.

[0086] The magnetic field strength sensor is electrically connected to the controller and is used to transmit the detected magnetic field strength signal to the controller in real time. The controller dynamically adjusts the drive current of each excitation coil according to the deviation between the detected signal and the preset magnetic field parameters, thereby realizing closed-loop control of the magnetic field.

[0087] In one embodiment, the controller can perform differentiated control on the excitation coils at different locations based on the spatial distribution information of the magnetic field strength, so that the magnetic field strength in each region of the mixing cavity is more uniform or meets specific distribution requirements, thereby improving the consistency of the movement of magnetic nanoparticles.

[0088] In one embodiment, the controller can also optimize and adjust the rate of change of current and phase relationship of the excitation coil according to the dynamic response of the magnetic field change, so as to compensate for the magnetic field lag or deviation caused by system inertia, electromagnetic coupling or external disturbance, thereby improving the response speed and stability of magnetic field control.

[0089] In addition, during system operation, when an abnormal magnetic field strength or deviation from the set range is detected, the controller can automatically correct the parameters or issue an alarm signal to avoid the magnetic field runaway from affecting the mixing effect and equipment safety.

[0090] Through the above closed-loop control method, the magnetic field generating unit can maintain a stable and controllable magnetic field output during dynamic operation, thereby ensuring that the magnetic nanoparticles move according to the expected trajectory in the mixing chamber, and improving the stability, consistency and repeatability of the active mixing process.

[0091] In one embodiment, the magnetic field strength sensor is a Hall sensor, which is disposed on the outer wall of the mixing cavity or near the mixing area, and is used to detect changes in the magnetic field strength inside the mixing cavity in real time.

[0092] The controller adjusts the drive current of each excitation coil using a closed-loop control algorithm based on the deviation between the detected magnetic field strength and the preset magnetic field target value, thereby achieving stable control of the magnetic field strength.

[0093] In one embodiment, the controller may also employ a proportional-integral-derivative (PID) control algorithm to dynamically correct the current amplitude, on / off timing, and phase relationship of the excitation coil in order to compensate for the effects of electromagnetic response lag or system disturbances.

[0094] Preferably, the magnetic field strength control error can be maintained within ±5%, thereby ensuring that the magnetic nanoparticles move stably in the mixing cavity according to a preset trajectory and improving the consistency of the mixing effect.

[0095] IX. Anti-adhesion control mechanism In one embodiment, to address the problem of high-viscosity polyurethane two-component systems easily adhering to the inner wall of the mixing cavity during the mixing process, the present invention uses a magnetic field to control the movement of magnetic nanoparticles, thereby actively suppressing the wall adhesion phenomenon.

[0096] Specifically, during the mixing process, due to the high viscosity of the polyol component and the gradual thickening or even solidification of the system during the reaction, some materials tend to form an adhesion layer on the inner wall of the mixing chamber and the surface of the flow guiding elements, thus creating stagnant areas or dead zones. This type of adhered material not only makes it difficult to participate in subsequent mixing but may also affect the cross-section of the fluid channel, thereby reducing mixing efficiency and increasing cleaning difficulty.

[0097] In one embodiment, the controller can control the electromagnetic coil array to generate a pulsed magnetic field at a specific stage of the mixing process or when an adhesion tendency is detected. The pulsed magnetic field is a type of magnetic field in which the magnetic field strength or direction changes rapidly over a short period of time, and its frequency and amplitude can be set according to the operating conditions.

[0098] Under the influence of a pulsed magnetic field, magnetic nanoparticles distributed within the mixing cavity migrate towards regions with higher or changing magnetic field strength due to the instantaneous magnetic field gradient, preferably moving towards the central region of the mixing cavity. During this process, the migration of the magnetic nanoparticles induces localized flow in the surrounding fluid, thereby applying shear and peeling forces to the material adhering to the cavity wall surface.

[0099] Furthermore, by periodically applying a pulsed magnetic field, a repetitive "desorption-redispersion" process can be formed within the mixing chamber, causing the material adhering to the chamber wall to be continuously carried away from the wall surface and re-participated in the mixing, thereby effectively suppressing the accumulation of wall adhesion.

[0100] In one embodiment, the anti-wall adhesion control can be performed in conjunction with the mixing control process, for example, by enhancing the effect of the pulsed magnetic field in the later stage of mixing or the flow rate reduction stage to focus on removing cavity wall residues; or by setting trigger conditions based on the magnetic field strength sensor or running time to achieve periodic or adaptive adjustment of the anti-wall adhesion control.

[0101] Furthermore, the anti-adhesion wall control mechanism, combined with the anti-adhesion coating on the inner wall of the mixing chamber, reduces material adhesion by lowering the adhesion force and achieves active peeling by magnetic field drive, thereby forming a synergistic effect of structure and control to improve the anti-adhesion wall effect.

[0102] Through the above methods, the present invention can effectively control the material adhering to the inner wall of the mixing chamber without relying on mechanical scraping or frequent shutdowns for cleaning, which is beneficial to improving the continuous operation capability of the system, reducing maintenance costs, and ensuring the stability of the mixing process.

[0103] 10. Control Methods In one embodiment, the present invention also provides a control method for a high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological regulation, applied to the system described in the above embodiment, and the process is as follows: Step S1 involves mixing the polyol component with surface-modified magnetic nanoparticles to prepare a magnetorheological polyol component with magnetorheological properties. Specifically, the magnetic nanoparticles can be dispersed in the polyol matrix through mechanical stirring, ultrasonic dispersion, or high-shear dispersion to form a stable and uniform dispersion system.

[0104] In step S2, the magnetorheological polyol component and the isocyanate component are respectively supplied to the inlet of the active mixing unit through their respective supply units and enter the mixing chamber according to a set ratio. During the supply process, the polyol component is preferably maintained within a preset temperature range to ensure its fluidity.

[0105] In step S3, the controller acquires the flow signals detected by the first and second mass flow meters in real time, and dynamically adjusts the volumetric pump and the variable frequency motor according to the deviation between the detection results and the preset ratio, so as to maintain the flow ratio of the magnetorheological polyol component and the isocyanate component within the target range, thereby achieving a stable metering supply of the two-component system.

[0106] In step S4, the controller controls the electromagnetic coil array to generate a dynamically changing magnetic field according to a preset mixing program. This causes the magnetic nanoparticles in the magnetorheological polyol component to move in a controlled manner within the mixing chamber, thereby disturbing the surrounding fluid and achieving active mixing of the two components. In this step, the dynamic magnetic field can be a rotating magnetic field, a traveling wave magnetic field, an oscillating magnetic field, or a combination thereof.

[0107] Preferably, the magnetic field strength of the dynamic magnetic field can be set to 0.1 T to 1.0 T, and the magnetic field change frequency can be set to 10 Hz to 500 Hz, so as to adapt to the mixing requirements under different viscosity and working conditions.

[0108] In step S5, the material that has been fully mixed in the active mixing unit is discharged through the outlet and transported to the subsequent foaming or molding process.

[0109] In one embodiment, the control method further includes a magnetic field feedback adjustment step: the controller adjusts the current of each excitation coil in real time according to the magnetic field distribution information detected by the magnetic field strength sensor, so as to realize closed-loop control of the magnetic field and thereby improve the stability and consistency of the mixing process.

[0110] In one embodiment, the control method further includes an anti-adhesion control step: during the mixing process or at a specific stage, the controller controls the electromagnetic coil array to generate a pulsed magnetic field, driving magnetic nanoparticles to move toward the central region of the mixing cavity, thereby causing the material adhering to the cavity wall surface to detach, thus suppressing the wall adhesion phenomenon.

[0111] By combining material conveying control, magnetic field regulation, and feedback adjustment through the above control methods, the high-viscosity polyurethane two-component system can achieve dynamic, controllable, and efficient mixing during the mixing process, thereby improving the stability of the foaming process and the consistency of product quality.

[0112] XI. Preferred Embodiments In a preferred embodiment, the high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control of the present invention is set with the following parameters.

[0113] The magnetorheological polyol component uses polyether polyol as a matrix and incorporates magnetic nanoparticles to form a magnetorheological system. The magnetic nanoparticles are preferably iron oxide particles, whose surface is modified with oleic acid to improve their dispersion stability in the polyol. The average particle size of the magnetic nanoparticles is 40 nm to 60 nm, preferably about 50 nm, and their mass percentage in the polyol component is 1.0% to 2.0%, preferably about 1.5%.

[0114] During the transport process, the magnetorheological polyol component is heated by a constant temperature control device, and the temperature is controlled within the range of 45℃ to 55℃, preferably about 52℃, in order to reduce the viscosity of the system and improve its fluidity.

[0115] In this embodiment, the flow rate of the magnetorheological polyol component is 10 kg / min to 15 kg / min, preferably about 12 kg / min; the flow rate of the isocyanate component is 2 kg / min to 3 kg / min, preferably about 2.2 kg / min. Through closed-loop adjustment of the proportional control unit, the mass ratio control error of the two components is maintained within ±1%, preferably within ±0.8%.

[0116] The mixing chamber of the active mixing unit is preferably cylindrical, with an inner diameter of 60 mm to 100 mm, preferably about 80 mm, and a length of 150 mm to 250 mm, preferably about 200 mm. The inner wall of the mixing chamber is provided with an anti-stick coating, preferably a polytetrafluoroethylene coating, to reduce material adhesion.

[0117] The magnetic field generating unit includes multiple excitation coils arranged along the axial direction of the mixing cavity. The number of excitation coils is 3 to 6, preferably 4, and each excitation coil is controlled by an independent drive circuit. The magnetic field strength is controlled within the range of 0.2 T to 0.8 T, preferably 0.3 T to 0.6 T, and the magnetic field variation frequency is 20 Hz to 200 Hz.

[0118] Under these conditions, a composite magnetic field is generated by controlling an array of electromagnetic coils, causing magnetic nanoparticles to move in multiple directions within the mixing chamber, thereby inducing enhanced turbulence in the fluid. Tests showed that the two-component materials can be uniformly mixed within 3 to 6 seconds.

[0119] In addition, during system operation, the controller can periodically apply a pulsed magnetic field to peel off the material adhering to the inner wall of the mixing chamber, thereby reducing wall adhesion and improving continuous operation stability.

[0120] It should be noted that the above embodiments are only one of the preferred embodiments of the present invention, and the specific parameters can be adjusted according to the actual working conditions. Any adjustments made without departing from the technical concept of the present invention are within the protection scope of the present invention.

[0121] 12. Comparison of Test Results To verify the mixing performance of the magnetorheologically controlled high-viscosity polyurethane two-component active mixing foaming system described in this invention in high-viscosity systems, comparative experiments were conducted on different mixing methods. The same batch of magnetorheological polyol component (component A) was used in the experiments, and mixing tests were performed under the same flow rate conditions to examine the mixing efficiency, mixing uniformity, cell quality, and cavity wall residue under different mixing modes.

[0122] In this comparative experiment, the magnetorheological material A used had a viscosity of 3600 mPa·s, and tests were conducted using various mixing methods, including mixing without a magnetic field, static mixer mixing, vortex mixing, ultrasonic-assisted mixing, and active mixing under different magnetic field modes of this invention. Test parameters included: mixing time, mixing uniformity, standard deviation of bubble diameter, and residual area of ​​the cavity wall. The experimental results are shown in the table below: Hybrid mode Mixed time (seconds) Mixing uniformity (%) Standard deviation of bubble diameter (mm) Residual area of ​​cavity wall (%) No magnetic field (only fluid flow) 10 78.5 0.052 8.2 Static mixer (comparison) 15 85.2 0.045 7.5 Swirl mixing (contrast) 12 82.6 0.048 9.1 Ultrasound-assisted (comparison) 8 91.3 0.032 5.3 This invention - rotating magnetic field 6 94.8 0.024 2.1 This invention - traveling wave magnetic field 7 95.2 0.022 1.8 This invention - composite magnetic field 8 99.2 0.015 0.5 The experimental results above show that, under no magnetic field conditions, relying solely on the fluid's own flow results in low mixing uniformity, significant dispersion in bubble diameter, and a high residual area on the cavity walls. This indicates that high-viscosity systems are difficult to mix thoroughly under laminar flow conditions. While static mixers and swirling mixers can improve mixing to some extent, they still suffer from insufficient mixing and large residual areas on the cavity walls under high-viscosity conditions. Ultrasonic-assisted mixing offers some improvement over the aforementioned methods, but it still falls short in terms of mixing uniformity, bubble structure consistency, and residual area control.

[0123] In comparison, the magnetorheological active mixing method employed in this invention significantly improves the mixing effect. In the rotating magnetic field mode, the mixing time is reduced to 6 seconds, the mixing uniformity increases to 94.8%, the standard deviation of bubble diameter decreases to 0.024 mm, and the residual cavity wall area decreases to 2.1%. In the traveling wave magnetic field mode, the mixing uniformity further increases to 95.2%, the standard deviation of bubble diameter decreases to 0.022 mm, and the residual cavity wall area is 1.8%. Furthermore, in the composite magnetic field mode, this invention achieves the best results, with a mixing uniformity of 99.2%, a bubble diameter standard deviation reduced to 0.015 mm, and a residual cavity wall area of ​​only 0.5%, indicating that the composite magnetic field mode can achieve more thorough and uniform active mixing in high-viscosity systems.

[0124] Experimental results show that the magnetorheological active mixing technology used in this invention is significantly superior to existing technologies in terms of mixing uniformity, mixing efficiency, cell quality, and self-cleaning effect. In particular, the composite magnetic field mode can achieve a near-ideal uniform mixing effect and almost completely eliminate cavity wall residue, thus fully demonstrating the technical advantages of this invention in the field of high-viscosity polyurethane two-component mixed foaming.

[0125] The embodiments described above are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make various modifications, substitutions, or equivalent transformations to the above embodiments without departing from the spirit and substance of the present invention, and all such modifications, substitutions, or equivalent transformations should fall within the scope of protection of the present invention.

[0126] It should be noted that the terms "including" and "comprising" used in this specification do not exclude the existence of other unlisted elements or steps; the terms "connection" and "connection" should be interpreted broadly, and can refer to direct connection or indirect connection through an intermediate medium, as long as the corresponding function can be achieved.

[0127] Furthermore, the technical features involved in the various embodiments described in the specification can be combined arbitrarily without conflict. The scope of protection of this invention is defined by the appended claims.

Claims

1. A high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control, characterized in that, include: A magnetorheological polyol supply unit is used to transport polyol components containing magnetic nanoparticles. Isocyanate supply unit for conveying isocyanate components; A proportional control unit is used to control the output ratio between the magnetorheological polyol supply unit and the isocyanate supply unit; An active mixing unit has its inlet connected to the outlets of the magnetorheological polyol supply unit and the isocyanate supply unit, respectively. The magnetic field generating unit includes an array of electromagnetic coils surrounding the active mixing unit; The controller is electrically connected to both the proportional control unit and the magnetic field generating unit. The controller is configured to: control the electromagnetic coil array to generate a dynamically changing magnetic field according to a preset mixing program, drive the magnetic nanoparticles in the polyol component to move along a preset trajectory inside the active mixing unit, so as to achieve active stirring and mixing of the fluid in the mixing chamber.

2. The high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control according to claim 1, characterized in that, The magnetorheological polyol supply unit includes a constant temperature control device and a volumetric delivery pump. The constant temperature control device includes a temperature sensor and a heating element, used to heat the polyol component to 40°C to 60°C. The isocyanate supply unit includes a precision metering pump driven by a variable frequency motor; The proportional control unit includes a first mass flow meter located at the outlet of the magnetorheological polyol supply unit and a second mass flow meter located at the outlet of the isocyanate supply unit. The controller is electrically connected to the first mass flow meter, the second mass flow meter, the volumetric pump, and the variable frequency motor.

3. The high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control according to claim 1, characterized in that, The magnetic nanoparticles in the polyol component have a particle size of 10 nm to 100 nm and a mass percentage of 0.5% to 3.0%, and the surface of the magnetic nanoparticles is coated with a coupling agent layer. The magnetic nanoparticles are selected from one or more of the following: iron(II,III) oxide, γ-ferric oxide, nickel-iron alloy, and cobalt-iron alloy. The coupling agent is selected from one or more of silane coupling agents, titanate coupling agents, and aluminate coupling agents.

4. The high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control according to claim 1, characterized in that, The electromagnetic coil array includes multiple independent excitation coils arranged sequentially along the axial direction of the active mixing unit, each excitation coil being controlled by an independent drive circuit.

5. The high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control according to claim 1, characterized in that, The active mixing unit includes: a mixing chamber with an anti-stick coating on its inner wall surface; a premixing structure disposed at the inlet end of the mixing chamber; and multiple flow guiding elements disposed within the mixing chamber. The flow guiding element is made of a non-magnetic material and has a microgroove structure on its surface.

6. The high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control according to claim 1, characterized in that, The controller is configured to execute at least one of the following control modes: rotating magnetic field mode, traveling wave magnetic field mode, oscillating magnetic field mode, and composite magnetic field mode; The system also includes a magnetic field strength sensor for real-time monitoring of the magnetic field strength distribution within the mixing cavity, and the controller dynamically adjusts the current of each excitation coil based on the feedback signal from the magnetic field strength sensor.

7. A control method for a high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step S1: Mix the polyol component with surface-modified magnetic nanoparticles to obtain a magnetorheological polyol component with magnetorheological properties. Step S2: The magnetorheological polyol component and the isocyanate component are delivered to the active mixing unit in a set ratio; Step S3: The controller acquires the flow rates of the magnetorheological polyol component and the isocyanate component in real time and dynamically adjusts the delivery ratio to keep them within the target range. Step S4: The controller controls the electromagnetic coil array to generate a dynamically changing magnetic field, driving the magnetic nanoparticles in the magnetorheological polyol component to move in the mixing chamber, so that the magnetorheological polyol component and the isocyanate component are mixed. Step S5: Discharge the mixed material.

8. The control method according to claim 7, characterized in that, In step S4, the dynamically changing magnetic field includes a rotating magnetic field, a traveling wave magnetic field, an oscillating magnetic field, or a composite magnetic field, with a magnetic field strength of 0.1 T to 1.0 T and a magnetic field change frequency of 10 Hz to 500 Hz.

9. The control method according to claim 7, characterized in that, It also includes an anti-adhesion control step: the controller controls the electromagnetic coil array to generate a pulsed magnetic field, which drives the magnetic nanoparticles to move towards the central region of the mixing chamber, thus peeling off the material attached to the chamber wall.

10. An application of a high-viscosity polyurethane two-component active mixing and foaming system based on magnetorheological control, characterized in that, The system according to any one of claims 1 to 6 is used to prepare highly filled flame-retardant polyurethane foam, high-viscosity polyurethane composite material or high-performance reaction injection molded article.

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