Preparation method of polyester type antistatic powder coating

Abstract

The invention relates to the technical field of polyester powder coatings, in particular to a preparation method of a polyester type antistatic powder coating. The method comprises the following steps: firstly, determining a flow inertia factor according to the viscosity of a pre-molten material and the heating condition among different sections; determining a thermal inertia factor according to the heat-conducting property of the pre-molten material, the influence of heated melting of the feeding particle size of the feeding in the melting section and the expected arrival time of the pre-molten material; matching the flow inertia factor sequence and the thermal inertia factor sequence to obtain a delay time difference; determining a state change factor of the pre-molten material according to the delay time difference, the viscosity of the pre-molten material and the propelling speed; according to the heat conduction performance and the state change factor of the pre-melted material, total energy fluctuation of the material in the time sequence due to unstable heat absorption is determined; and the optimal feeding speed is determined according to the change of the total energy fluctuation in the material propelling length. The material agglomeration probability can be reduced through the regulation and control strategy.

Description

Technical Field

[0001] The present invention relates to the technical field of polyester powder coatings, and particularly relates to a preparation method of a polyester-based antistatic powder coating. Background Art

[0002] With the increasing demand for anti-static in fields such as electronic device manufacturing and petrochemical industry, polyester-based powder coatings have become the mainstream protective materials due to their excellent mechanical properties and chemical resistance. Polyester resin, as the matrix material, is prepared by adding conductive fillers and curing agents, combined with additives such as leveling agents and defoaming agents, through steps such as melt blending, extrusion granulation, and crushing and screening. Among them, conductive fillers such as carbon black, graphene, carbon nanotubes or metal powders, and curing agents such as triglycidyl isocyanurate.

[0003] However, the core technical problem of the existing process is that during the preparation of polyester-based antistatic powder coatings, the dispersion uniformity of conductive fillers in the resin matrix is insufficient, resulting in large fluctuations in the surface resistivity of the coating and unstable antistatic performance. Although existing methods attempt to improve the dispersion effect through mechanical stirring, such as high-speed dispersion at 1200 r / min, or ultrasonic treatment, nano-conductive fillers with a high specific surface area, such as graphene, are still prone to agglomeration, forming secondary particles of 3 - 10 μm, and it is difficult to form a continuous conductive path, affecting the antistatic performance. Summary of the Invention

[0004] In order to solve the technical problem that conductive fillers are prone to agglomeration during the preparation of polyester-based antistatic powder coatings, the purpose of the present invention is to provide a preparation method of a polyester-based antistatic powder coating, and the specific technical solution adopted is as follows: In the first aspect, an embodiment of the present invention provides a preparation method of a polyester-based antistatic powder coating, and the method includes: Obtain the advancing speed of the pre-molten material; Determine the flow inertia factor of the pre-molten material according to the viscosity of the pre-molten material and the heat absorption situation between different sections; Determine the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feeding particle size of the feeding in the melting section on heat melting, and the expected arrival duration of the pre-molten material predicted by the advancing speed; Match the flow inertia factor sequence and the thermal inertia factor sequence, and obtain the delay time difference at different moments; according to the delay time difference and the viscosity and advancing speed of the pre-molten material at the corresponding moment, determine the state change factor of the pre-molten material entering the melting section; Determine the total energy fluctuation absorbed by the material due to unsteady heat over time according to the thermal conductivity of the pre-molten material and the state change factor; determine the target feeding speed according to the change of the total energy fluctuation in the material propulsion length; combine the target feeding speed and the reference value of the feeding speed to determine the optimal feeding speed for preparing the polyester antistatic powder coating.

[0005] Further, determining the flow inertia factor of the pre-molten material according to the viscosity of the pre-molten material and the heating conditions between different sections includes: Determine the viscous flow degree of the pre-molten material according to the propulsion speed of the pre-molten material and the viscosity of the material at the melting section; Determine the section effect value according to the section length difference between the feeding section and the melting section; Determine the change of the melting rate according to the section temperature difference between the feeding section and the melting section; Determine the flow inertia factor of the pre-molten material according to the viscous flow degree, the section effect value and the change of the melting rate; wherein, both the viscous flow degree and the section effect value are positively correlated with the flow inertia factor, and the change of the melting rate is negatively correlated with the flow inertia factor.

[0006] Further, determining the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feeding particle size on the melting of the material fed at the melting section, and the expected arrival duration of the pre-molten material predicted by the propulsion speed includes: Determine the material property factor according to the material density, specific heat capacity and feeding particle size of the pre-molten material; Determine the heat-receiving property factor according to the expected arrival duration and the thermal conductivity; Determine the real-time thermal inertia factor according to the material property factor and the heat-receiving property factor; wherein, the material property factor is positively correlated with the thermal inertia factor; the heat-receiving property factor is negatively correlated with the thermal inertia factor.

[0007] Further, the method for obtaining the expected arrival duration is: Take any moment as the moment to be measured, and determine the expected arrival duration corresponding to the moment to be measured of the pre-molten material according to the section length of the pre-molten material from the outlet of the melting section at the moment to be measured and the propulsion speed of the pre-molten material.

[0008] Further, matching the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different moments includes: Use the DTW algorithm to match the flow inertia factor sequence and the thermal inertia factor sequence, and calculate the time difference between each moment in the thermal inertia factor sequence and the corresponding moment in the matched flow inertia factor sequence to obtain the delay time difference at each moment in the thermal inertia factor sequence.

[0009] Further, determining the state change factor of the pre-molten material entering the melting section according to the delay time difference and the viscosity and propulsion speed of the pre-molten material at the corresponding moment includes: Calculating the difference in the viscosity of the pre-molten material at two moments corresponding to the delay time difference as the viscosity difference; wherein, the two moments corresponding to the delay time difference are respectively the moment corresponding to the element in the thermal inertia factor sequence and the moment corresponding to the element in the flow inertia factor sequence; Calculating the average value of the propulsion speed of the pre-molten material within the time period between the two moments corresponding to the delay time difference as the overall speed; Determining the state change factor of the pre-molten material entering the melting section according to the viscosity difference, the overall speed and the delay time difference; wherein, the overall speed and the delay time difference are negatively correlated with the state change factor, and the viscosity difference is positively correlated with the state change factor.

[0010] Further, determining the total energy fluctuation absorbed by the material due to unsteady heat in time sequence according to the thermal conductivity of the pre-molten material and the state change factor includes: Calculating the product of the mass, specific heat capacity and temperature difference of the pre-molten material to obtain the heat expectation; Combining the state change factor and the heat expectation to determine the total energy fluctuation absorbed by the material due to unsteady heat in time sequence.

[0011] Further, determining the target feeding speed according to the change of the total energy fluctuation in the propulsion length of the material includes: Calculating the integral of the square value of the derivative of the total energy fluctuation between the propulsion lengths of the feeding section and the melting section as the target optimization parameter; Taking the smaller value of the target optimization parameter as the best target optimization parameter; Taking the feeding speed at the moment corresponding to the best target optimization parameter as the target feeding speed.

[0012] Further, combining the target feeding speed and the feeding speed reference value to determine the best feeding speed for preparing the polyester type antistatic powder coating includes: Taking the average value of the target feeding speed and the feeding speed reference value as the best feeding speed for preparing the polyester type antistatic powder coating.

[0013] Further, the method for obtaining the propulsion speed is: Obtaining the screw propulsion speed, the cross-sectional area of the screw groove and the pressure of the pre-molten material of the screw; Calculating the product of the screw propulsion speed and the cross-sectional area of the screw groove of the screw as the intermediate parameter of the pre-molten material; Take the ratio of the pressure value at the junction of the feeding section and the melting section and the intermediate parameters as the filling rate at the junction of the feeding section and the melting section; Derive the filling rate to obtain the advancing speed of the pre-molten material.

[0014] In a second aspect, a preparation system for a polyester-based antistatic powder coating is provided. The system includes the following modules: A data acquisition module for acquiring the advancing speed of the pre-molten material; A flow analysis module for determining the flow inertia factor of the pre-molten material according to the viscosity of the pre-molten material and the heat reception conditions between different sections; A thermal analysis module for determining the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feeding particle size on heat melting during feeding in the melting section, and the expected arrival duration of the pre-molten material predicted by the advancing speed; A state analysis module for matching the sequence of flow inertia factors and the sequence of thermal inertia factors to obtain the delay time difference at different times; and determining the state change factor of the pre-molten material entering the melting section according to the delay time difference and the viscosity and advancing speed of the pre-molten material at the corresponding time; A determination module for determining the total energy fluctuation absorbed by the material due to non-steady-state heat in time series according to the thermal conductivity of the pre-molten material and the state change factor; determining the target feeding speed according to the change of the total energy fluctuation in the advancing length of the material; and determining the optimal feeding speed for preparing the polyester-based antistatic powder coating by combining the target feeding speed and the feeding speed reference value.

[0015] In a third aspect, an embodiment of the present invention provides an electronic device, including a memory and a processor. An executable code is stored in the memory. When the processor executes the executable code, the embodiments of all possible implementations in the first aspect are implemented.

[0016] In a fourth aspect, an embodiment of the present invention provides a computer program product, which includes: computer program code. When the computer program code runs on a computer, the computer is caused to execute the method in the first aspect or any possible implementation manner in the first aspect.

[0017] In a fifth aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed in a computer, the computer is caused to execute the embodiments of all possible implementations in the first aspect.

[0018] The embodiments of the present invention have at least the following beneficial effects: In the preparation process of polyester antistatic powder coatings, during the mixing and extrusion of the conductive filler and resin matrix mixture, problems such as insufficient distribution uniformity and agglomeration effect affecting antistatic performance are likely to occur. In the present invention, the performance is improved by adding a modified additive during premixing, and then for the segmented temperature control system in the extruder, in different sections, especially between the feeding section and the melting section, the temperature suddenly rises, resulting in the material being unevenly heated due to flow inertia and thermal inertia, causing time-space delay and melting difference, and forming agglomeration. Therefore, first calculate the flow inertia factor and thermal inertia factor of the material. Additionally, by adding a side feeding port and adding fiber fillers to inhibit the flow inertia of the molten state of the material at the junction of the feeding section and the melting section, calculate the delay time difference according to the flow inertia factor and thermal inertia factor, obtain the total energy fluctuation absorbed by the material due to non-steady-state heat within the delay time difference, then dynamically adjust the feeding speed according to the minimum energy fluctuation gradient, and then constrain the feeding speed to avoid the problem of uneven filling rate; using the regulation strategy of the present invention can greatly reduce the probability of material agglomeration and improve the antistatic performance of polyester powder coatings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a flowchart of a method for preparing a polyester antistatic powder coating provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of different regions of a melt extruder provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the change in filling rate at different screw speeds during uniform feeding provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of the change in filling rate when simultaneously regulating different feeding speeds at different screw speeds provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in combination with the accompanying drawings and preferred embodiments, details the specific implementation manner, structure, features, and effects of a method for preparing a polyester antistatic powder coating according to the present invention.

[0022] In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0023] Wherein, in the description of the embodiments of the present invention, unless otherwise specified, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present invention, "a plurality of" means two or more than two.

[0024] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and should not be construed as implying or suggesting relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0026] The embodiments of the present invention will be described below with reference to the accompanying drawings. As known to those of ordinary skill in the art, with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present invention are equally applicable to similar technical problems.

[0027] The following specifically describes the specific solution of a preparation method of a polyester-based antistatic powder coating provided by the present invention with reference to the accompanying drawings.

[0028] Please refer to Figure 1 , which shows a step flowchart of a preparation method of a polyester-based antistatic powder coating provided by an embodiment of the present invention. The method includes the following steps: Step S100, obtain the propulsion speed of the pre-molten material.

[0029] First, pre-mix the pre-molten material: Use a double planetary mixer for pre-mixing. And by adding 0.5%-1% of polycarboxylate dispersant, perform surface modification on graphene or carbon nanotubes to reduce the surface energy of the filler and enhance the continuity of the conductive network, reducing the tendency of agglomeration. Among them, graphene and carbon nanotubes are conductive fillers. It should be noted that the operating rotation speed range of the double planetary mixer during pre-mixing is 400-600 r / min, and the operating duration is 4-6 min.

[0030] During pre-mixing, use the gradient feeding method: Step 1: Slowly mix the polyester resin with 0.5% sodium polycarboxylate dispersant to form a matrix wetting layer. It should be noted that the operating rotation speed range during slow mixing is 400 r / min, and the operating duration is 2 min; among them, 0.5% sodium polycarboxylate dispersant has been pre-dissolved in propylene glycol methyl ether acetate solvent.

[0031] Step 2: Add graphene or carbon nanotubes in 3 batches, with an interval of 30 seconds between each batch, and simultaneously start high-speed dispersion and vacuum degassing to eliminate bubbles. It should be noted that the operating rotation speed range during high-speed dispersion is 600 r / min, the operating duration is 3 min, and the vacuum degree of vacuum degassing is -0.09 MPa.

[0032] Step 3: Supplement the remaining 0.5% dispersant and reduce the speed to 450 r / min and maintain for 1 min to balance the interfacial tension.

[0033] In the resin formulation, the proportion of rigid monomers in the polyester resin can be selectively increased to improve the agglomeration problem. Rigid monomers such as neopentyl glycol.

[0034] Install a temperature sensor and an on-line rheometer in the stirring tank to monitor the viscosity-temperature curve in real time. The target is a viscosity of 800 - 1200 mPa·s at 25°C. When it is detected that the local viscosity mutation is greater than 1500 mPa·s, "pulse reverse stirring" is automatically triggered to break the filler agglomerates. It should be noted that the pulse reverse stirring is to rotate counterclockwise at 50 r / min for 5 seconds, with an interval of 10 seconds.

[0035] Stir the pre-molten material, and after stirring, feed it into the melt extruder. According to the resin type, such as the polyester-TGIC system, set the initial parameters of the melt extruder. The preset temperature range for each zone of the melt extruder is as follows: the preset temperature range for the feeding section is 90 - 100°C, which is used for preheating and avoiding feeding blockage caused by premature melting; the preset temperature range for the melting section is 110 - 125°C, which is used for high-temperature heating and melting and dynamically adjusting according to the resin melting situation; the preset temperature range for the homogenization section is 105 - 115°C, which is used for balancing the risks of dispersion and thermal degradation. Please refer to Figure 2 , Figure 2 for the schematic diagrams of different zones of the melt extruder; where a1 is the feeding section, a2 is the melting section, and a3 is the homogenization section.

[0036] Then, retrieve the historical process data of the same type of product through the MES system, and generate an initial parameter combination in combination with the material ratio; among them, the historical process data such as extrusion temperature, screw speed, and feeding speed; the material ratio such as the conductive filler accounts for 3% - 8%.

[0037] Using a machine learning model, predict the initial screw rotation speed range and feeding speed, and set a pressure threshold to prevent equipment overload. Among them, the machine learning module can adopt the random forest algorithm, the initial screw rotation speed range is 300 - 600 r / min, the feeding speed is 20 - 30 kg / h, and the pressure threshold range is ≤8 Mpa.

[0038] Furthermore, adjust the extrusion parameters of the resin to optimize the product performance.

[0039] Install infrared temperature sensors and pressure transmitters at each section of the extruder to collect melt temperature and shear pressure data in real time. Monitor the change of melt viscosity through an on-line viscometer and dynamically feedback it to the control system; the on-line viscometer such as a capillary rheometer.

[0040] The existing control strategy is to adjust the feeding speed according to the real-time ratio of the melt viscosity and screw torque feedback by the sensor. When the melt viscosity is greater than the threshold, it means that the filler dispersion is insufficient, and the system automatically raises the temperature and increases the screw rotation speed, but it is necessary to ensure that the residence time of the material is within the range of 30 - 60 seconds.

[0041] However, in the actual production extruder, the influence of the coating melt state and different sections of the extruder is not immediate and purely linear. Therefore, the decoupling analysis of the static physical state of the coating in different sections of the extruder based only on static thresholds is not credible; in actual production, it is found that due to the heat conduction delay and material flow inertia in each section of the extruder, there is a lag in the spatio-temporal matching of the melt viscosity and pressure data feedback by the sensor with the actual process state, resulting in the deviation of the timing of temperature increase and speed adjustment from the optimal window, leading to the risk of insufficient resin crosslinking or thermal degradation.

[0042] The feeding section plays a role in pre-melting. However, the temperature suddenly rises after entering the melting section. If it is set to gradient heating, the heating distance needs to be lengthened, which is limited by the length of the melting section. Its melting speed is too fast, increasing the flow inertia. There are differences in the molten state when the material first enters the melting section, and the state differences between the front and rear materials are large, resulting in uneven resin state and viscosity distribution in the extruder, causing local connection stress damage, and instantaneously forming an agglomeration phenomenon when the temperature drops after entering the homogenization section.

[0043] Real-time monitor the temperature and pressure of the pre-molten material through the temperature sensor in the feeding section and the pressure transmitter at the entrance of the melting section. Here, the pre-molten material can also be understood as the coating melt.

[0044] Furthermore, obtain the screw propulsion speed and the cross-sectional area of the screw groove of the screw. It should be noted that the screw propulsion speed and the cross-sectional area of the screw groove of the screw are operating data or fixed data that can be obtained by the implementer.

[0045] In the embodiments of the present invention, a local overload signal is fed back by a pressure sensor to measure the local pressure value at the junction of the feeding section and the melting section, and then the filling rate is monitored to obtain the advancing speed of the pre-molten material. Specifically: calculate the product of the screw advancing speed of the screw and the cross-sectional area of the screw groove as an intermediate parameter of the pre-molten material; take the ratio of the pressure value at the junction of the feeding section and the melting section to the intermediate parameter as the filling rate at the junction of the feeding section and the melting section. Then, take the derivative of the filling rate to obtain the advancing speed of the pre-molten material.

[0046] Step S200: Determine the flow inertia factor of the pre-molten material according to the viscosity of the pre-molten material and the heat absorption situation between different sections.

[0047] Obtain the temperature difference between the feeding section and the melting section, the lengths of the respective sections of the feeding section and the melting section, and the real-time viscosity of the material at the melting section. It should be noted that the viscosity of the pre-molten material at the melting section can be obtained by a viscometer.

[0048] Determine the viscous flow degree of the pre-molten material according to the advancing speed of the pre-molten material and the viscosity of the material at the melting section; Determine the section effect value according to the section length difference between the feeding section and the melting section; Determine the melting rate change according to the temperature difference between the feeding section and the melting section. Specifically: take the temperature difference between the feeding section and the melting section as the melting rate change.

[0049] Determine the flow inertia factor of the pre-molten material according to the viscous flow degree, the section effect value and the melting rate change; wherein, both the viscous flow degree and the section effect value are positively correlated with the flow inertia factor, and the melting rate change is negatively correlated with the flow inertia factor.

[0050] In some embodiments, the calculation formula of the flow inertia factor Q is: ; where n is the viscosity; is the advancing speed of the pre-molten material; is the viscous flow degree of the pre-molten material; is the melting rate change; ln is the natural logarithm function; is the length of the feeding section; is the length of the melting section.

[0051] The numerator term of the flow inertia factor is the product of the real-time viscosity of the material and the square of the real-time advancing speed of the material. The square of the speed represents the kinetic energy, indicating the viscous flow kinetic energy. The denominator term reflects the melting rate change caused by the temperature difference drive. It represents the spatio-temporal effect of correcting the section length difference using logarithmic terms and characterizes the momentum accumulation effect caused by temperature jump. It should be noted that each moment has its corresponding flow inertia factor.

[0052] Step S300, determine the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feed particle size fed in the melting section on heat melting, and the expected arrival duration of the pre-molten material predicted by the propulsion speed.

[0053] In the embodiment of the present invention, a new side feed port is added. According to the real-time monitored filling rate, a corresponding amount of fiber filler is fed in at a fixed ratio during side feeding.

[0054] When the pre-molten material enters the melting section, the added fiber filler can reduce the flow inertia of the material by increasing the melt shear resistance and reducing the kinetic energy gradient of the material flow, balance the melting speed difference at the inlet of the melting section, inhibit the sudden change of flow inertia caused by a sudden temperature rise, and further prevent agglomeration problems.

[0055] The pre-molten material moves continuously in the extruder and is subjected to unsteady heat. First, obtain the heat transfer delay in different sections of the extruder, that is, the length between the feeding section and the melting section. Here, the length is the section length of the molten material from the outlet of the melting section.

[0056] Taking any moment as the moment to be measured, determine the expected arrival duration of the pre-molten material corresponding to the moment to be measured according to the section length of the pre-molten material from the outlet of the melting section at the moment to be measured and the propulsion speed of the pre-molten material.

[0057] The longer the expected arrival duration of the pre-molten material, the longer the heating time of the corresponding pre-molten material.

[0058] Then, due to the influence of the feeding speed, when the material starts to absorb heat and undergoes melting deformation, this process may have a certain lag, which is called thermal inertia.

[0059] Determine the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feed particle size fed in the melting section on heat melting, and the expected arrival duration of the pre-molten material predicted by the propulsion speed.

[0060] The thermal conductivity of the pre-molten material includes the thermal conductivity of the pre-molten material. In the embodiment of the present invention, the real-time heat transfer amount can be characterized by the product value of the thermal conductivity and the obtained expected arrival duration.

[0061] The thermal inertia factor reflects the heat transfer process, and the flow inertia factor reflects the tendency of the material to flow. In theory, melting and flowing of the material occur only after the heat transfer ends. If the occurrence time of the flow inertia is not synchronized with the occurrence time of the thermal inertia, it means that there is the occurrence of unsteady heat, resulting in the pre-molten material melting and deforming earlier or later.

[0062] According to the material density, specific heat capacity, and feed particle size of the pre-molten material, determine the material property factor; according to the expected arrival duration and thermal conductivity, determine the heat-receiving property factor; according to the material property factor and the heat-receiving property factor, determine the real-time thermal inertia factor. Among them, the material property factor is positively correlated with the thermal inertia factor; the heat-receiving property factor is negatively correlated with the thermal inertia factor. Thermal inertia reflects the lag of melting. The material property factors are all determined by the properties of the material itself, density, specific heat capacity, and particle size, while the heat-receiving property factor is determined by the properties of the material when heated, time, and thermal conductivity.

[0063] In some embodiments, the pre-molten material at the t-th moment The calculation formula for the thermal inertia factor is: ; where is the material density; is the specific heat capacity; is the feed particle size; is the material property factor; is the expected arrival time of the material at the t-th moment; is the thermal conductivity; is the heat-receiving property factor.

[0064] Step S400, match the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different moments; according to the delay time difference and the viscosity and propulsion speed of the pre-molten material at the corresponding moment, determine the state change factor of the pre-molten material entering the melting section.

[0065] Construct a thermal inertia factor sequence from the thermal inertia factors at different moments; construct a flow inertia factor sequence from the flow inertia factors at different moments. It should be noted that both the thermal inertia factor sequence and the flow inertia factor sequence are arranged in time sequence.

[0066] Perform DTW alignment on the thermal inertia factor sequence and the flow inertia factor sequence to achieve the matching of the flow inertia factor sequence and the thermal inertia factor sequence. According to the time series matching results, obtain multiple matching pairs, each matching pair containing an element from the flow inertia factor sequence and an element from the thermal inertia factor sequence, where each element has its corresponding moment. Calculate the time difference between each moment in the thermal inertia factor sequence and the moment of the flow inertia factor that matches it, and the unsteady thermal-melting delay time difference at each moment can be obtained. It should be noted that this delay time difference is the moment in the thermal inertia factor sequence minus the moment in the flow inertia factor sequence that matches it.

[0067] Obtain the unsteady thermal-melting delay time difference, that is, the moment when the material just reaches the junction position + the delay time difference tk at the current moment, which is the delay time when the material just reaches the junction between the feeding section and the melting section and then undergoes melting after a short delay. The additional change in the melting state that occurs synchronously in the material that has entered during this time.

[0068] Determine the state change factor of the pre-molten material entering the melting section based on the delay time difference and the viscosity and propulsion speed of the pre-molten material at the corresponding moment.

[0069] Calculate the difference in the viscosity of the pre-molten material at the two moments corresponding to the delay time difference as the viscosity difference; among them, the two moments corresponding to the delay time difference are the moment corresponding to the element in the thermal inertia factor sequence and the moment corresponding to the element in the flow inertia factor sequence respectively; Calculate the average value of the propulsion speed of the pre-molten material during the time period between the two moments corresponding to the delay time difference as the overall speed; Determine the state change factor of the pre-molten material entering the melting section based on the viscosity difference, the overall speed, and the delay time difference; among them, the overall speed and the delay time difference are negatively correlated with the state change factor, and the viscosity difference is positively correlated with the state change factor.

[0070] In some embodiments, the calculation formula for the state change factor H is: ; where is the viscosity difference; is the moment corresponding to the element in the thermal inertia factor sequence corresponding to the delay time difference; is the moment corresponding to the element in the flow inertia factor sequence corresponding to the delay time difference; is the overall speed; is the delay time difference.

[0071] The state change factor represents that when the melting state is affected by temperature changes, the material that enters the melting section first has a delay in the melting state change caused by heat transfer in addition to the basic time difference compared to the material that enters the melting section later.

[0072] Step S500: Determine the total energy fluctuation absorbed by the material due to unsteady heat in terms of time sequence according to the thermal conductivity of the pre-molten material and the state change factor; determine the target feeding speed according to the change of the total energy fluctuation in the advancing length of the material; and determine the optimal feeding speed for preparing the polyester antistatic powder coating by combining the target feeding speed and the reference value of the feeding speed.

[0073] The total energy fluctuation absorbed by the material from the feeding section to before and after the melting section can be estimated. Specifically, obtain the product of the material mass, the specific heat capacity of the material and the temperature difference to get the heat expectation.

[0074] However, the material is subjected to unsteady heat during continuous movement. Therefore, combine the state change factor and the heat expectation to determine the total energy fluctuation absorbed by the material due to unsteady heat in terms of time sequence. More specifically: Take the difference between the heat expectation and the state change factor of the pre-molten material to obtain the total energy fluctuation absorbed by the material due to unsteady heat in terms of time sequence.

[0075] The total energy fluctuation reflects the agglomeration risk caused by the influence of unsteady heat and spatio-temporal hysteresis when the material crosses different sections.

[0076] The feeding speed affects the filling rate, and then directly affects the strength of the shearing action, and the melting temperature also decreases accordingly. Therefore, the feeding speed - advancing speed needs to be coordinated to enable the material to be heated stably. Under different feeding speeds, there are overflow feeding and starvation feeding, resulting in dynamic changes in the energy absorbed by the material in each section.

[0077] Therefore, calculate the total energy fluctuation gradient of the material under different feeding speeds, and optimize the feeding speed according to the minimum total energy fluctuation gradient.

[0078] Specifically: Calculate the integral of the square value of the derivative of the total energy fluctuation between the advancing lengths of the feeding section and the melting section as the target optimization parameter; Take the target optimization parameter with the smaller value as the optimal target optimization parameter; Take the feeding speed at the moment corresponding to the optimal target optimization parameter as the target feeding speed.

[0079] In some embodiments, the optimal target optimization parameter The calculation formula is: ; where, min is the function of taking the minimum value; is the starting position of the pre-molten material; is the current position of the pre-molten material; is to take the derivative of the total energy fluctuation of the material; is the target optimization parameter. Integrating the square of the total energy fluctuation gradient along the advancing path of the pre-molten material aims to avoid the cancellation of positive and negative gradients, thereby more strictly measuring the severity of energy changes.

[0080] The optimal target optimization parameter is the one corresponding to the minimum integral of the square of the total energy fluctuation gradient, and the corresponding feeding speed is the target feeding speed for the current material state. It should be noted that this feeding speed refers to the target feeding speed of the material state corresponding to each moment when the screw rotates at a uniform speed.

[0081] Furthermore, it is also necessary to consider that the dynamic adjustment of the feeding speed and the screw speed may cause instability of the filling rate, resulting in local overload or underload, which affects the mixing effect.

[0082] Please refer to Figure 3 and Figure 4 , Figure 3 is a schematic diagram of the change in the filling rate at different screw speeds during uniform feeding, Figure 3 in which the screw speeds 1, 2, and 3 increase in sequence; Figure 4 is a schematic diagram of the change in the filling rate when adjusting different feeding speeds simultaneously at different screw speeds, Figure 4 in which the feeding speeds 1, 2, and 3 decrease in sequence.

[0083] As the feeding speed decreases, the filling rate of the group with a relatively large original screw speed drops significantly compared to the filling rate during uniform feeding; because the high-speed screw will accelerate the forward conveying speed of the material, which makes the material in the screw groove unable to be fully filled.

[0084] Therefore, when the screw speed changes, the feeding speed is synchronously restricted by the screw speed, and the two show a direct proportional relationship; Calibrate the proportional coefficient using experimental data. According to the experimental data, at the target filling rate, adjust the feeding speed and synchronously change the screw speed, calculate the ratio of multiple groups of feeding speeds and screw speeds, and their influence on the target filling rate. Then, use the least squares method to fit the experimental data, and obtain the fitted slope value as the proportional coefficient; When dynamically adjusting the feeding speed, multiply the screw speed by the proportional coefficient to obtain the reference value of the feeding speed, denoted as the feeding speed reference value; Then, take the average of the obtained target feeding speed and this feeding speed reference value as the real-time feeding speed control value, which is also the optimal feeding speed for preparing the polyester-based antistatic powder coating.

[0085] Use the proportional coefficient to constrain the feeding speed to avoid the problem of unstable filling rate caused by the overly mismatched feeding speed and rotation speed.

[0086] In addition, when the pressure sensor monitors that the pressure > 7 MPa, there is a risk of filler agglomeration and blockage, triggering speed reduction protection, reducing the screw speed by 15%, and starting the self-cleaning function of the reverse screw section.

[0087] Finally, cool and grind to obtain an antistatic powder coating with good conductivity.

[0088] By adjusting the extrusion process, the agglomeration risk of the material can be greatly reduced, the formation of secondary particles can be avoided. After extrusion, it is quickly cooled by an ice-water cooling press, pressed into sheets and immediately broken into pieces to reduce particle adhesion at high temperatures.

[0089] Adopt a two-stage cooling system: The first-stage cooling roller has a surface temperature of 10 - 15 °C, quickly cools to below 80 °C to prevent thermal oxidation of the resin; The second-stage water-cooled belt has a flow rate of 2 m / s and is further cooled to 40 °C to form a uniform thin sheet.

[0090] According to the hardness of the thin sheet, it is detected by an acoustic emission sensor, and the main grinding speed and the secondary grinding gap of the ACM grinder are dynamically adjusted. It should be noted that the main grinding speed range of the ACM grinder is 8000 - 10000 r / min, and the secondary grinding gap range is 0.5 - 1 mm.

[0091] Configure an intelligent vibrating screen, monitor the oversize in real time through image recognition technology, trigger the self-cleaning of the screen mesh in time, and upload the screening data to the quality traceability system. It should be noted that the range of the intelligent vibrating screen is 180 - 200 mesh.

[0092] The embodiment of the present invention provides a preparation system for a polyester-based antistatic powder coating, and the system includes: A data acquisition module for acquiring the propulsion speed of the pre-molten material; A flow analysis module for determining the flow inertia factor of the pre-molten material according to the viscosity of the pre-molten material and the heat absorption situation between different sections; A thermal analysis module for determining the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feed particle size of the feed in the melting section on heat melting, and the expected arrival time of the pre-molten material predicted by the propulsion speed; A state analysis module for matching the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different moments; determining the state change factor of the pre-molten material entering the melting section according to the delay time difference and the viscosity and propulsion speed of the pre-molten material at the corresponding moment; A determination module, configured to determine the total energy fluctuation absorbed by the material due to unsteady heat in time series according to the thermal conductivity of the pre-molten material and the state change factor; determine the target feeding speed according to the change of the total energy fluctuation in the material feeding length; and determine the optimal feeding speed for preparing the polyester antistatic powder coating by combining the target feeding speed and the reference value of the feeding speed.

[0093] Optionally, the transmission medium may be a wired link, such as but not limited to, coaxial cable, optical fiber, digital subscriber line, etc., or a wireless link, such as but not limited to, Wireless Fidelity (WIFI), Bluetooth, mobile device network, etc.

[0094] It should be noted that: for the device provided in the above embodiment, only the division of the above functional modules is used for illustration. In actual application, the above functions may be allocated to different functional modules according to needs, that is, the internal structure of the computer device is divided into different functional modules to complete all or part of the functions described above.

[0095] A computer device provided by an embodiment of the present invention. Exemplarily, the computer device includes: a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the computer device can execute any one of the preparation methods of the polyester antistatic powder coating described above.

[0096] In addition, an embodiment of the present invention also protects a device, which may include a memory and a processor. Among them, an executable program code is stored in the memory, and the processor is used to call and execute the executable program code to execute a preparation method of a polyester antistatic powder coating provided by an embodiment of the present invention.

[0097] The embodiment of the present invention can divide the functions of the device according to the above method examples. For example, each function module can be corresponding, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is illustrative, only a logical function division, and there may be other division methods in actual implementation.

[0098] In the case of dividing each module corresponding to each function, the device may further include a signal uploading module, a determination module, an adjustment module, etc. It should be noted that all relevant contents of each step involved in the above method embodiment can be cited in the function description of the corresponding functional module, and will not be repeated here.

[0099] It should be understood that the device provided in the embodiments of the present invention is used to execute the above-mentioned preparation method of a polyester-type antistatic powder coating, so the same effects as those of the above-mentioned implementation method can be achieved.

[0100] In the case of adopting integrated units, the device may include a processing module and a storage module. Among them, when the device is applied to a device, the processing module can be used to control and manage the actions of the device. The storage module can be used to support the device to execute mutual program codes, etc. Among them, the processing module can be a processor or a controller, which can implement or execute various exemplary logic blocks, modules and circuits described in connection with the disclosure of the present invention. The processor can also be a combination that realizes computing functions, such as including a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module can be a memory.

[0101] In addition, the device provided in the embodiments of the present invention can specifically be a chip, a component or a module. The chip may include a connected processor and a memory; wherein, the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute the preparation method of a polyester-type antistatic powder coating provided in the above embodiments.

[0102] The embodiments of the present invention also provide a computer-readable storage medium, in which computer program codes are stored. When the computer program codes run on a computer, the computer is enabled to execute the above-mentioned related method steps to implement the preparation method of a polyester-type antistatic powder coating provided in the above embodiments.

[0103] The embodiments of the present invention also provide a computer program product. When the computer program product runs on a computer, the computer is enabled to execute the above-mentioned related steps to implement the preparation method of a polyester-type antistatic powder coating provided in the above embodiments.

[0104] Among them, the device, computer-readable storage medium, computer program product or chip provided in the embodiments of the present invention are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be elaborated here. Through the description of the above embodiments, those skilled in the art can understand that for the convenience and simplicity of description, only the above-mentioned division of each functional module is used as an example for illustration. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In the embodiments provided by the present invention, it should be understood that the disclosed device and method can be implemented in other ways.

[0105] The device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling, direct coupling, or communication connection to each other can be through some interfaces. The indirect coupling or communication connection of devices or units can be in electrical, mechanical, or other forms.

[0106] It should also be noted that in this text, the term "including", "comprising", or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or terminal device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article, or terminal device. Without more limitations, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article, or terminal device including the said element.

[0107] It should be noted that the above sequence of embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0108] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0109] The above content is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A preparation method of a polyester-based antistatic powder coating, characterized in that, The method includes the following steps: Obtain the advancing speed of the pre-molten material; Determine the flow inertia factor of the pre-molten material according to the viscosity of the pre-molten material and its heat-receiving conditions between different sections; Determine the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feed particle size in the melting section on heat melting, and the expected arrival duration of the pre-molten material predicted by the advancing speed; Match the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different times; determine the state change factor of the pre-molten material entering the melting section according to the delay time difference and the viscosity and advancing speed of the pre-molten material at the corresponding time; Determine the total energy fluctuation absorbed by the material due to non-steady-state heat in time series according to the thermal conductivity of the pre-molten material and the state change factor; determine the target feeding speed according to the change of the total energy fluctuation in the advancing length of the material; combine the target feeding speed and the reference value of the feeding speed to determine the optimal feeding speed for preparing the polyester antistatic powder coating.

2. The preparation method of the polyester antistatic powder coating according to claim 1, characterized in that, The step of determining the flow inertia factor of the pre-molten material according to the viscosity of the pre-molten material and its heat-receiving conditions between different sections includes: Determine the viscous flow degree of the pre-molten material according to the advancing speed of the pre-molten material and the viscosity of the material at the melting section; Determine the section effect value according to the section length difference between the feeding section and the melting section; Determine the change of the melting rate according to the section temperature difference between the feeding section and the melting section; Determine the flow inertia factor of the pre-molten material according to the viscous flow degree, the section effect value and the change of the melting rate; wherein, both the viscous flow degree and the section effect value are positively correlated with the flow inertia factor, and the change of the melting rate is negatively correlated with the flow inertia factor.

3. The preparation method of the polyester antistatic powder coating according to claim 1, characterized in that The step of determining the thermal inertia factor according to the thermal conductivity of the pre-molten material, the influence of the feed particle size in the melting section on heat melting, and the expected arrival duration of the pre-molten material predicted by the advancing speed includes: Determine the material property factor according to the material density, specific heat capacity of the pre-molten material and the feed particle size; Determine the heat-receiving property factor according to the expected arrival duration and the thermal conductivity; Determine the real-time thermal inertia factor according to the material property factor and the heat-receiving property factor; wherein, the material property factor is positively correlated with the thermal inertia factor; the heat-receiving property factor is negatively correlated with the thermal inertia factor.

4. The preparation method of the polyester antistatic powder coating according to claim 3, characterized in that, The method for obtaining the expected arrival duration is: Take any moment as the moment to be measured, and determine the expected arrival duration corresponding to the moment to be measured of the pre-molten material according to the section length of the pre-molten material from the outlet of the melting section at the moment to be measured and the advancing speed of the pre-molten material.

5. The preparation method of the polyester antistatic powder coating according to claim 1, characterized in that, The step of matching the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different times includes: Use the DTW algorithm to match the flow inertia factor sequence and the thermal inertia factor sequence, calculate the time difference between each moment in the thermal inertia factor sequence and the corresponding moment in the matched flow inertia factor sequence, and obtain the delay time difference of each moment in the thermal inertia factor sequence.

6. The preparation method of the polyester-based antistatic powder coating according to claim 1, characterized in that, Determining the state change factor of the pre-molten material entering the melting section according to the time difference of delay and the viscosity and propulsion speed of the pre-molten material at the corresponding moment, including: Calculating the difference in the viscosities of the pre-molten material at two moments corresponding to the time difference of delay as the viscosity difference; wherein, the two moments corresponding to the time difference of delay are respectively the moments corresponding to the elements in the thermal inertia factor sequence and the moments corresponding to the elements in the flow inertia factor sequence; Calculating the average value of the propulsion speed of the pre-molten material within the time period between the two moments corresponding to the time difference of delay as the overall speed; Determining the state change factor of the pre-molten material entering the melting section according to the viscosity difference, the overall speed, and the time difference of delay; wherein, the overall speed and the time difference of delay are negatively correlated with the state change factor, and the viscosity difference is positively correlated with the state change factor.

7. The preparation method of the polyester-based antistatic powder coating according to claim 1, characterized in that, Determining the total energy fluctuation absorbed by the material due to unsteady heat in time series according to the thermal conductivity of the pre-molten material and the state change factor, including: Calculating the product of the mass, specific heat capacity, and temperature difference of the pre-molten material to obtain the heat expectation; Combining the state change factor and the heat expectation to determine the total energy fluctuation absorbed by the material due to unsteady heat in time series.

8. The preparation method of the polyester-based antistatic powder coating according to claim 1, characterized in that, Determining the target feeding speed according to the change of the total energy fluctuation in the propulsion length of the material, including: Calculating the integral of the square value of the derivative of the total energy fluctuation between the propulsion lengths of the feeding section and the melting section as the target optimization parameter; Taking the smaller value of the target optimization parameter as the best target optimization parameter; Taking the feeding speed at the moment corresponding to the best target optimization parameter as the target feeding speed.

9. The preparation method of the polyester antistatic powder coating according to claim 1, characterized in that, Combining the target feeding speed and the feeding speed reference value to determine the best feeding speed for preparing the polyester antistatic powder coating, including: Taking the average value of the target feeding speed and the feeding speed reference value as the best feeding speed for preparing the polyester antistatic powder coating.

10. The preparation method of the polyester-based antistatic powder coating according to claim 1, wherein, The method for obtaining the propulsion speed is: Obtaining the screw propulsion speed, the cross-sectional area of the screw groove, and the pressure of the pre-molten material of the screw; Calculating the product of the screw propulsion speed of the screw and the cross-sectional area of the screw groove as the intermediate parameter of the pre-molten material; Taking the ratio of the pressure value at the junction position between the feeding section and the melting section to the intermediate parameter as the filling rate at the junction position between the feeding section and the melting section; Taking the derivative of the filling rate to obtain the propulsion speed of the pre-molten material.

Images