A method for preparing polyester antistatic powder coating

Abstract

The present invention relates to the technical field of polyester powder coatings, and specifically to a method for preparing polyester antistatic powder coatings. The method first determines the flow inertia factor based on the viscosity of the pre-melted material and the heating conditions between different sections; determines the thermal inertia factor based on the thermal conductivity of the pre-melted material, the influence of the feeding particle size of the feed in the melting section on the thermal melting, and the expected arrival time of the pre-melted material; matches the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference; determines the state change factor of the pre-melted material based on the delay time difference, the viscosity of the pre-melted material and the advancement speed; determines the total energy fluctuation absorbed by the material in time due to non-steady-state heat based on the thermal conductivity and state change factor of the pre-melted material; and determines the optimal feeding speed based on the change of the total energy fluctuation in the material advancement length. The present invention can reduce the probability of material agglomeration through a control strategy.

Description

Technical Field

[0001] The invention relates to the technical field of polyester powder coatings, and in particular to a method for preparing a polyester antistatic powder coating. Background Art

[0002] With the increasing demand for anti-static in electronic equipment manufacturing, petrochemicals and other fields, polyester powder coatings have become the mainstream protective material due to their excellent mechanical properties and chemical resistance. Polyester resin is used as the matrix material, and is prepared by adding conductive fillers and curing agents, combined with leveling agents, defoaming agents and other additives, through 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 existing processes lies in the insufficient uniformity of the conductive filler dispersion within the resin matrix during the preparation of polyester antistatic powder coatings. This results in large fluctuations in the coating's surface resistivity and unstable antistatic performance. Although existing methods attempt to improve dispersion through mechanical agitation, such as high-speed dispersion at 1200 rpm, or ultrasonic treatment, high-surface-area nano-conductive fillers, such as graphene, are prone to agglomeration, forming secondary particles of 3-10 μm. This makes it difficult to form a continuous conductive path, thus affecting antistatic performance. Summary of the Invention

[0004] In order to solve the technical problem that conductive fillers are prone to agglomeration when preparing polyester antistatic powder coatings, the purpose of the present invention is to provide a method for preparing polyester antistatic powder coatings. The technical solution adopted is as follows:

[0005] In a first aspect, an embodiment of the present invention provides a method for preparing a polyester antistatic powder coating, the method comprising:

[0006] Obtain the advancing speed of the pre-melted material;

[0007] Determine the flow inertia factor of the pre-melted material based on its viscosity and the heat conditions between different sections;

[0008] The thermal inertia factor is determined based on the thermal conductivity of the pre-melted material, the effect of the feed particle size in the melting section on the thermal melting, and the expected arrival time of the pre-melted material predicted by the advancing speed.

[0009] 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-melted material entering the melting section based on the delay time difference and the viscosity and propulsion speed of the pre-melted material at the corresponding time;

[0010] Based on the thermal conductivity and state change factor of the pre-melted material, the total energy fluctuation absorbed by the material due to non-steady-state heat in time is determined; based on the change of the total energy fluctuation in the material advancement length, the target feeding rate is determined; combined with the target feeding rate and the feeding rate reference value, the optimal feeding rate for preparing polyester antistatic powder coating is determined.

[0011] Furthermore, the flow inertia factor of the pre-melted material is determined according to the viscosity of the pre-melted material and the heating conditions between different sections, including:

[0012] Determining the viscous flow degree of the pre-melted material according to the advancing speed of the pre-melted material and the viscosity of the material in the melting section;

[0013] The section effect value is determined based on the section length difference between the feeding section and the melting section;

[0014] Determine the change in melting rate based on the temperature difference between the feeding section and the melting section;

[0015] The flow inertia factor of the pre-melted material is determined according to the viscous flow degree, the segment effect value and the melting rate change; wherein the viscous flow degree and the segment effect value are both positively correlated with the flow inertia factor, and the melting rate change is negatively correlated with the flow inertia factor.

[0016] Furthermore, the thermal inertia factor is determined based on the thermal conductivity of the pre-melted material, the effect of the particle size of the feed in the melting section on the thermal melting, and the expected arrival time of the pre-melted material predicted by the advancing speed, including:

[0017] Determine the material property factor based on the material density, specific heat capacity and feed particle size of the pre-melted material;

[0018] Determine the heating attribute factor based on the expected arrival time and thermal conductivity;

[0019] The real-time thermal inertia factor is determined based on the material property factor and the heat property factor. The material property factor is positively correlated with the thermal inertia factor, while the heat property factor is negatively correlated with the thermal inertia factor.

[0020] Furthermore, the method for obtaining the expected arrival time is:

[0021] Taking any moment as the time to be measured, the expected arrival time of the pre-melted material at the time to be measured is determined according to the length of the section from the pre-melted material to the outlet of the melting section at the time to be measured and the advancing speed of the pre-melted material.

[0022] Furthermore, the matching of the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different times includes:

[0023] The flow inertia factor sequence and the thermal inertia factor sequence are matched using the DTW algorithm. The time difference between each moment in the thermal inertia factor sequence and the corresponding moment in the matched flow inertia factor sequence is calculated to obtain the delay time difference of each moment in the thermal inertia factor sequence.

[0024] Furthermore, the state change factor of the pre-melted material entering the melting section is determined based on the delay time difference and the viscosity and advancing speed of the pre-melted material at the corresponding moment, including:

[0025] Calculating the difference in viscosity of the pre-melted 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 moments corresponding to the elements in the thermal inertia factor sequence and the moments corresponding to the elements in the flow inertia factor sequence;

[0026] Calculate the average value of the advancing speed of the pre-melted material in the time period between the two moments corresponding to the delay time difference as the overall speed;

[0027] The state change factor of the pre-melted material entering the melting section is determined based on 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.

[0028] Furthermore, determining the total energy fluctuation absorbed by the material due to non-steady-state heat in a temporal manner based on the thermal conductivity and state change factor of the pre-melted material includes:

[0029] Calculate the product of the mass, specific heat capacity and temperature difference of the pre-melted material to obtain the heat expectation;

[0030] The total energy fluctuation absorbed by the material due to non-steady-state heat in a time sequence is determined by combining the state change factor and the thermal expectation.

[0031] Furthermore, determining the target feeding speed according to the change of the total energy fluctuation in the material advancing length includes:

[0032] Calculate the integral of the square value of the derivative of the total energy fluctuation between the advancement length of the feeding section and the melting section as the target optimization parameter;

[0033] The target optimization parameter with the smallest value is taken as the best target optimization parameter;

[0034] The feeding speed at the moment corresponding to the best target optimization parameter is taken as the target feeding speed.

[0035] Furthermore, the method of determining the optimal feeding speed for preparing the polyester antistatic powder coating by combining the target feeding speed and the feeding speed reference value includes:

[0036] The average value of the target feeding rate and the feeding rate reference value is taken as the optimal feeding rate for preparing polyester antistatic powder coating.

[0037] Furthermore, the method for obtaining the propulsion speed is:

[0038] Obtain the screw advancement speed, screw groove cross-sectional area and pre-melted material pressure of the screw;

[0039] Calculate the product of the screw advancement speed and the screw groove cross-sectional area as the intermediate parameter of the pre-melted material;

[0040] The ratio of the pressure value at the interface between the feeding section and the melting section to the intermediate parameter is used as the filling rate at the interface between the feeding section and the melting section;

[0041] The filling rate is derived to obtain the advancing speed of the pre-melted material.

[0042] In a second aspect, a system for preparing a polyester antistatic powder coating is provided, the system comprising the following modules:

[0043] A data acquisition module is used to obtain the advancing speed of the pre-melted material;

[0044] Flow analysis module, used to determine the flow inertia factor of the pre-melted material based on the viscosity of the pre-melted material and the heating conditions between different sections;

[0045] Thermal analysis module, used to determine the thermal inertia factor based on the thermal conductivity of the pre-melted material, the effect of the feed particle size on the melting stage, and the expected arrival time of the pre-melted material predicted by the advancing speed;

[0046] The state analysis module is used to match the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different times; based on the delay time difference and the viscosity and propulsion speed of the pre-melted material at the corresponding time, the state change factor of the pre-melted material entering the melting section is determined;

[0047] The determination module is used to determine the total energy fluctuation absorbed by the material due to non-steady-state heat in a time sequence based on the thermal conductivity and state change factor of the pre-melted material; determine the target feeding speed based on the change of the total energy fluctuation in the material advancement length; and determine the optimal feeding speed for preparing polyester antistatic powder coatings in combination with the target feeding speed and the feeding speed reference value.

[0048] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores executable code, and when the processor executes the executable code, various possible implementations of the first aspect are implemented.

[0049] In a fourth aspect, an embodiment of the present invention provides a computer program product, which includes: computer program code, which, when running on a computer, enables the computer to execute the method in the above-mentioned first aspect or any possible implementation of the first aspect.

[0050] In a fifth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed in a computer, the computer is caused to execute various possible implementations of the first aspect.

[0051] The embodiments of the present invention have at least the following beneficial effects:

[0052] In view of the problem that the conductive filler and the resin matrix mixture are prone to insufficient distribution uniformity during the stirring and extrusion process during the preparation of polyester antistatic powder coatings, agglomeration effect occurs and affects the antistatic performance. The present invention improves the performance by adding a modifying additive during premixing. Then, a segmented temperature control system in the extruder is proposed. Different sections, especially between the feeding section and the melting section, are subjected to a sudden temperature increase. This causes the material to experience spatiotemporal delays and melting differences due to flow inertia and thermal inertia, resulting in non-uniform heating of the material and agglomeration. Therefore, the flow inertia factor and thermal inertia factor of the material are first calculated. In addition, a side feeding port is added and a fiber filler is added to suppress the flow inertia of the molten material at the junction of the feeding section and the melting section. The delay time difference is calculated based on the flow inertia factor and the thermal inertia factor, and the total energy fluctuation absorbed by the material due to non-steady-state heat within the delay time difference is obtained. Then, the feeding speed is dynamically adjusted according to the gradient of minimizing the energy fluctuation, and the feeding speed is constrained to avoid the problem of uneven filling rate. The control strategy of the present invention can significantly reduce the probability of material agglomeration and improve the antistatic performance of the polyester powder coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 A flow chart of a method for preparing a polyester antistatic powder coating provided by one embodiment of the present invention;

[0055] Figure 2 A schematic diagram of different areas of a melt extruder provided by one embodiment of the present invention;

[0056] Figure 3 A schematic diagram of changes in filling rate at different screw speeds during uniform feeding provided by one embodiment of the present invention;

[0057] Figure 4 A schematic diagram of the change in filling rate when different feeding rates are simultaneously controlled at different screw speeds provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following, in combination with the accompanying drawings and preferred embodiments, describes in detail a method for preparing a polyester antistatic powder coating proposed in accordance with the present invention, its specific implementation method, structure, characteristics and effects.

[0059] In the following description, different references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, the particular features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0060] In the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" refers to two or more than two.

[0061] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0062] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0063] The embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present invention are also applicable to similar technical problems.

[0064] The specific scheme of the preparation method of the polyester antistatic powder coating provided by the present invention is described in detail below with reference to the accompanying drawings.

[0065] See also Figure 1 , which shows a flow chart of the steps of a method for preparing a polyester antistatic powder coating provided by one embodiment of the present invention, the method comprising the following steps:

[0066] Step S100, obtaining the advancing speed of the pre-melted material.

[0067] First, pre-mix the pre-melted materials:

[0068] A dual planetary mixer is used for premixing. 0.5%-1% sodium polycarboxylate dispersant is added to modify the graphene or carbon nanotube surface, reducing the filler's surface energy, enhancing the continuity of the conductive network, and reducing agglomeration. Graphene and carbon nanotubes are conductive fillers. The dual planetary mixer operates at a speed range of 400-600 rpm for premixing, with a run time of 4-6 minutes.

[0069] When premixing, use a gradient addition method:

[0070] Step 1: The polyester resin was mixed with a 0.5% sodium polycarboxylate dispersant at a low speed to form a substrate wetting layer. The low-speed mixing was performed at a speed of 400 rpm for 2 minutes. The 0.5% sodium polycarboxylate dispersant was pre-dissolved in propylene glycol methyl ether acetate.

[0071] Step 2: Add graphene or carbon nanotubes in three batches, with a 30-second interval between each batch. Simultaneously activate high-speed dispersion and vacuum degassing to eliminate bubbles. The high-speed dispersion process operates at a speed of 600 rpm for 3 minutes, and the vacuum level for vacuum degassing is -0.09 MPa.

[0072] Step 3: Add the remaining 0.5% dispersant and reduce the speed to 450 r / min and maintain for 1 min to balance the interfacial tension.

[0073] 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.

[0074] A temperature sensor and an online rheometer are embedded in the mixing tank to monitor the viscosity-temperature curve in real time. The target viscosity is 800-1200 mPa·s at 25°C. When a localized viscosity increase exceeding 1500 mPa·s is detected, pulsed reverse stirring is automatically triggered to break up filler agglomerates. Pulsed reverse stirring involves rotating counterclockwise at 50 rpm for 5 seconds, followed by a 10-second interval.

[0075] The pre-melted material is stirred and then fed into the melt extruder. Based on the resin type, such as polyester-TGIC system, the initial parameters of the melt extruder are set, and the temperature range of each zone of the melt extruder is preset: the preset temperature range of the feeding section is 90-100℃, which is used for preheating and to avoid premature melting that causes feed blockage; the preset temperature range of the melting section is 110-125℃, which is used for high-temperature heating and melting and is dynamically adjusted according to the resin melting situation; the preset temperature range of the homogenization section is 105-115℃, which is used to balance dispersion and thermal degradation risks. Figure 2 , Figure 2 Schematic diagram of different areas of a melt extruder; a1 is the feeding section, a2 is the melting section, and a3 is the homogenizing section.

[0076] Then, the historical process data of similar products is retrieved through the MES system, and the initial parameter combination is generated in combination with the material ratio; among them, the historical process data includes extrusion temperature, screw speed, and feeding speed; the material ratio includes conductive fillers accounting for 3%-8%.

[0077] Use a machine learning model to predict the initial screw speed range and feed rate, and set a pressure threshold to prevent equipment overload. The machine learning module can use a random forest algorithm, with an initial screw speed range of 300-600 rpm, a feed rate of 20-30 kg / h, and a pressure threshold of ≤8 MPa.

[0078] Furthermore, the extrusion parameters of the resin are adjusted to optimize product performance.

[0079] Infrared temperature sensors and pressure transmitters are installed at each section of the extruder to collect real-time melt temperature and shear pressure data. Melt viscosity changes are monitored using an online viscometer, such as a capillary rheometer, and dynamic feedback is provided to the control system.

[0080] The existing control strategy is to adjust the feeding speed based on the real-time ratio of melt viscosity to screw torque fed back by the sensor. When the melt viscosity exceeds the threshold, it means that the filler is insufficiently dispersed. The system automatically increases the temperature and screw speed, but it is necessary to ensure that the material residence time is within the range of 30-60 seconds.

[0081] However, in actual production of extruders, the influence of the coating melt state and the different sections of the extruder is not instantaneous and purely linear. Therefore, the decoupling analysis of the static physical state of the coating in different sections of the extruder based solely on the static threshold is not credible. In actual production, it was found that due to the heat conduction delay and material flow inertia of each section of the extruder, the melt viscosity and pressure data fed back by the sensor have a lag in the temporal and spatial matching with the actual process state, resulting in the timing of temperature increase and speed adjustment deviating from the optimal window, causing insufficient resin cross-linking or thermal degradation risks.

[0082] The feeding section plays the role of pre-melting, but the temperature rises suddenly after entering the melting section. If it is set to gradient heating, the heating distance must be lengthened, which will be limited by the length of the melting section. The melting speed is too fast, which will increase the flow inertia. The material will show a difference in melting state as soon as it enters the melting section. The state of the material at the front and the material at the back are quite different, which makes the resin state and viscosity in the extruder unevenly distributed, causing local connection stress damage. When entering the homogenization section, the temperature drops and agglomeration occurs instantly.

[0083] The temperature and pressure of the pre-melted material are monitored in real time by the temperature sensor in the feeding section and the pressure transmitter at the inlet of the melting section. The pre-melted material here can also be understood as the coating melt.

[0084] Furthermore, the screw advancement speed and the screw groove cross-sectional area of the screw are obtained. It should be noted that the screw advancement speed and the screw groove cross-sectional area of the screw are operating data or fixed data that can be obtained by the implementer.

[0085] In an embodiment of the present invention, a pressure sensor provides feedback of a local overload signal to measure the local pressure at the interface between the feeding and melting sections, thereby monitoring the filling rate and obtaining the advance speed of the pre-melted material. Specifically, the product of the screw's advancement speed and the cross-sectional area of the screw groove is calculated as an intermediate parameter of the pre-melted material. The ratio of the pressure at the interface between the feeding and melting sections to the intermediate parameter is used as the filling rate at the interface between the feeding and melting sections. The advance speed of the pre-melted material is then derived by taking the derivative of the filling rate.

[0086] Step S200 : determining the flow inertia factor of the pre-melted material according to the viscosity of the pre-melted material and the heating conditions between different sections.

[0087] The temperature difference between the feeding section and the melting section, as well as the length of each section of the feeding section and the melting section are obtained, and the real-time viscosity of the material in the melting section is obtained. It should be noted that the viscosity of the pre-melted material in the melting section can be obtained using a viscometer.

[0088] Determine the viscous flow degree of the pre-melted material according to the advancing speed of the pre-melted material and the viscosity of the material in the melting section;

[0089] The section effect value is determined based on the section length difference between the feeding section and the melting section;

[0090] The melting rate change is determined according to the temperature difference between the feeding section and the melting section. Specifically, the temperature difference between the feeding section and the melting section is taken as the melting rate change.

[0091] The flow inertia factor of the pre-melted material is determined according to the viscous flow degree, the segment effect value and the melting rate change; wherein the viscous flow degree and the segment effect value are both positively correlated with the flow inertia factor, and the melting rate change is negatively correlated with the flow inertia factor.

[0092] In some embodiments, the flow inertia factor Q is calculated as: ; Where n is viscosity; is the advancing speed of the pre-melted material; is the viscous flow degree of the pre-melted material; is the change of melting rate; ln is the natural logarithmic function; is the length of the feeding section; is the length of the melting section.

[0093] The numerator of the flow inertia factor is the product of the real-time viscosity of the material and the square of the real-time propulsion velocity of the material. The square of the velocity represents the magnitude of the kinetic energy, which indicates the viscous flow kinetic energy. The denominator reflects the change in melting rate caused by the temperature difference. This represents the temporal and spatial effects of segment length differences corrected using logarithmic terms, characterizing the momentum accumulation effect caused by the temperature jump. It should be noted that each moment has its own corresponding flow inertia factor.

[0094] Step S300 , determining a thermal inertia factor based on the thermal conductivity of the pre-melted material, the effect of thermal melting on the particle size of the pre-melted material fed in the melting section, and the expected arrival time of the pre-melted material predicted by the advancing speed.

[0095] In the embodiment of the present invention, a side feeding port is newly added, and a corresponding amount of fiber filler is fed in a fixed ratio during side feeding according to the filling rate monitored in real time.

[0096] When the pre-melted material enters the melting section, the added fiber filler increases the melt shear resistance, reduces the kinetic energy gradient of the material flow, reduces the material flow inertia, balances the melting velocity difference at the melting section entrance, and suppresses the sudden change of flow inertia caused by the sudden temperature rise, as well as further agglomeration problems.

[0097] The pre-melted material is constantly moving in the extruder and is subjected to non-steady-state heat. Therefore, the heat transfer delay within the different sections of the extruder is first determined, i.e., the length between the material feeding section and the melting section. Here, the length is the distance from the molten material to the melting section outlet.

[0098] Taking any moment as the time to be measured, the expected arrival time of the pre-melted material at the time to be measured is determined according to the length of the section from the pre-melted material to the outlet of the melting section at the time to be measured and the advancing speed of the pre-melted material.

[0099] The longer the expected arrival time of the pre-melted material is, the longer the heating time of the corresponding pre-melted material is.

[0100] Then, due to the influence of feeding speed, when the material begins to absorb heat and then melt and deform, there may be a certain hysteresis, which is called thermal inertia.

[0101] The thermal inertia factor is determined based on the thermal conductivity of the pre-melted material, the effect of the feed particle size in the melting section on the thermal melting, and the expected arrival time of the pre-melted material predicted by the advancing speed.

[0102] The thermal conductivity of the pre-melted material includes the thermal conductivity of the pre-melted material. In the embodiment of the present invention, the real-time heat transfer amount can be represented by the product value of the thermal conductivity and the obtained expected arrival time.

[0103] The thermal inertia factor reflects the heat transfer process, and the flow inertia factor reflects the material flow trend. In theory, the material will melt and flow only after the heat transfer is completed. If the flow inertia occurrence time is not synchronized with the thermal inertia occurrence time, it means that non-steady-state heat occurs, causing the pre-melted material to melt and deform earlier or later.

[0104] The material property factor is determined based on the pre-melted material's density, specific heat capacity, and feed particle size. The heat property factor is determined based on the expected arrival time and thermal conductivity. The real-time thermal inertia factor is determined based on the material property factor and the heat property factor. The material property factor and the thermal inertia factor are positively correlated, while the heat property factor and the thermal inertia factor are negatively correlated. Thermal inertia reflects the hysteresis of melting. The material property factors are determined by the material's inherent properties: density, specific heat capacity, and particle size, while the heat property factor is determined by the material's properties during heating: time and thermal conductivity.

[0105] In some embodiments, the pre-melted material at time t The calculation formula of thermal inertia factor is: ;in, 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 tth moment; is thermal conductivity; is the thermal property factor.

[0106] Step S400, matching the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different times; determining the state change factor of the pre-melted material entering the melting section according to the delay time difference and the viscosity and advancement speed of the pre-melted material at the corresponding time.

[0107] The thermal inertia factor sequence is constructed from the thermal inertia factors at different times; the flow inertia factor sequence is constructed from the flow inertia factors at different times. It should be noted that the thermal inertia factor sequence and the flow inertia factor sequence are both arranged in time sequence.

[0108] The thermal inertia factor sequence and the flow inertia factor sequence are aligned using DTW to match the flow inertia factor sequence and the thermal inertia factor sequence. Based on the timing matching results, multiple matching pairs are obtained. Each matching pair contains an element from the flow inertia factor sequence and an element from the thermal inertia factor sequence, where each element has its own corresponding time. The time difference between each moment of the thermal inertia factor sequence and its matching flow inertia factor moment is calculated to obtain the delay time difference of the non-steady-state thermal-melting at each moment. It should be noted that this delay time difference is the moment in the thermal inertia factor sequence minus the matching moment in the flow inertia factor sequence.

[0109] Obtain the delay time difference of non-steady-state heat-melting, that is, the delay time difference tk of the moment when the material just arrives at the junction position + the current moment, which is the additional change in the melting state of the material that occurs synchronously during the delay time when the material just arrives at the junction of the feeding section and the melting section and then melts after a short delay.

[0110] The state change factor of the pre-melted material entering the melting section is determined according to the delay time difference and the viscosity and advancing speed of the pre-melted material at the corresponding moment.

[0111] Calculating the difference in viscosity of the pre-melted 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 moments corresponding to the elements in the thermal inertia factor sequence and the moments corresponding to the elements in the flow inertia factor sequence;

[0112] Calculate the average value of the advancing speed of the pre-melted material in the time period between the two moments corresponding to the delay time difference as the overall speed;

[0113] The state change factor of the pre-melted material entering the melting section is determined based on 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.

[0114] In some embodiments, the state change factor H is calculated as: ;in, is the viscosity difference; is the time corresponding to the element in the thermal inertia factor sequence corresponding to the delay time difference; is the time corresponding to the element in the flow inertia factor sequence corresponding to the delay time difference; is the overall speed; The delay time difference.

[0115] The state change factor represents the delay in the change of the melting state caused by the delay in heat transfer in addition to the basic time difference between the material entering the melting section first and the material entering the melting section later when the temperature changes.

[0116] Step S500: Determine the total energy fluctuation absorbed by the material due to non-steady-state heat in a time sequence based on the thermal conductivity and state change factor of the pre-melted material; determine the target feeding speed based on the change of the total energy fluctuation in the material advancement length; and determine the optimal feeding speed for preparing the polyester antistatic powder coating by combining the target feeding speed and the feeding speed reference value.

[0117] The total energy fluctuation absorbed by the material from the feeding section to the melting section can be estimated. Specifically, the product of the material mass, the material specific heat capacity and the temperature difference is obtained to obtain the heat expectation.

[0118] However, the material is constantly in motion and is subject to non-steady-state heat. Therefore, the state change factor and the thermal expectation are combined to determine the total energy fluctuations absorbed by the material over time due to non-steady-state heat. More specifically, the difference between the thermal expectation and the state change factor of the pre-melted material is used to determine the total energy fluctuations absorbed by the material over time due to non-steady-state heat.

[0119] The total energy fluctuation reflects the agglomeration risk of materials caused by non-steady-state heat and time-space hysteresis when crossing different sections.

[0120] The feeding speed affects the filling rate, which in turn directly affects the strength of the shearing effect, and the melting temperature also decreases accordingly. Therefore, the feeding speed and the advancing speed need to be coordinated to ensure that the material temperature is stably heated. Different feeding speeds are divided into overflow feeding and starvation feeding, resulting in dynamic changes in the energy absorbed by the material in each section.

[0121] Therefore, the total energy fluctuation gradient of the material under different feeding speeds is calculated, and the feeding speed is optimized based on the minimum total energy fluctuation gradient.

[0122] Specifically: Calculate the integral of the square value of the derivative of the total energy fluctuation between the advancement length of the feeding section and the melting section as the target optimization parameter;

[0123] The target optimization parameter with the smallest value is taken as the best target optimization parameter;

[0124] The feeding speed at the moment corresponding to the best target optimization parameter is taken as the target feeding speed.

[0125] In some embodiments, the optimal target optimization parameters The calculation formula is: ; Wherein, min is the minimum value function; is the starting position of the pre-melted material; is the current position of the pre-melted material; To find the derivative of the total energy fluctuation of the material; The square of the total energy fluctuation gradient is integrated along the advancing path of the pre-melted material to avoid the mutual cancellation of positive and negative gradients, thereby more strictly measuring the severity of energy changes.

[0126] The optimal target optimization parameter is the one that minimizes the square integral of the total energy fluctuation gradient. The corresponding feeding rate is the target feeding rate for the current material state. It should be noted that this feeding rate refers to the target feeding rate for the material state at each moment, assuming uniform screw speed.

[0127] Furthermore, it is also necessary to consider that the dynamic adjustment of the feeding rate and the screw speed may cause the filling rate to be unstable, resulting in local overload or underload, and affecting the mixing effect.

[0128] See also Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the filling rate changes at different screw speeds during uniform feeding. Figure 3 The screw speed 1, screw speed 2, and screw speed 3 increase in sequence; Figure 4 This is a schematic diagram of the change in filling rate when different feeding rates are controlled at different screw speeds. Figure 4 The feeding speed 1, feeding speed 2 and feeding speed 3 decrease in sequence.

[0129] As the feeding speed decreases, the filling rate of the group with a higher screw speed drops significantly when feeding relatively evenly; this is because the high-speed screw will speed up the forward conveying speed of the material, which makes it impossible to fully fill the material in the screw groove.

[0130] Therefore, when the screw speed changes, the feeding speed is limited by the synchronous speed of the screw, and the two are in direct proportional relationship;

[0131] The proportional coefficient is calibrated using experimental data. Based on the experimental data, the feeding speed is adjusted and the screw speed is changed synchronously at the target filling rate. The effect of multiple sets of feeding speed and screw speed ratios on the target filling rate is calculated. The experimental data is then fitted using the least squares method to obtain the slope value after fitting as the proportional coefficient.

[0132] When dynamically adjusting the feeding speed, multiply the screw speed by the proportional coefficient to obtain the reference value of the feeding speed, which is recorded as the feeding speed reference value;

[0133] Then the obtained target feeding speed and the average value of the feeding speed reference value are used as the real-time feeding speed control value, that is, the optimal feeding speed for preparing polyester antistatic powder coating.

[0134] The feeding speed is constrained by the proportional coefficient to avoid the mismatch between the feeding speed and the rotation speed, which may cause the filling rate to be unstable.

[0135] In addition, when the pressure sensor monitors a pressure > 7MPa, there is a risk of filler agglomeration and clogging, triggering the speed reduction protection, reducing the screw speed by -15%, and starting the reverse spiral section self-cleaning function.

[0136] Finally, the milled powder is cooled to obtain an antistatic powder coating with good conductivity.

[0137] By regulating the extrusion process, the risk of material agglomeration can be greatly reduced, and the formation of secondary particles can be avoided. After extrusion, the tablet press is cooled quickly by ice water, and the material is immediately broken into pieces after being pressed into sheets, reducing the adhesion of particles at high temperatures.

[0138] Adopting two-stage cooling system:

[0139] The surface temperature of the first-stage cooling roller is 10-15℃, which is quickly cooled to below 80℃ to prevent thermal oxidation of the resin;

[0140] The secondary water cooling zone has a flow rate of 2m / s and is further cooled to 40°C to form uniform thin sheets.

[0141] According to the hardness of the thin slices, the main grinding speed and auxiliary grinding gap of the ACM grinding mill are dynamically adjusted through the acoustic emission sensor. It should be noted that the main grinding speed range of the ACM grinding mill is 8000-10000r / min, and the auxiliary grinding gap range is 0.5-1mm.

[0142] The intelligent vibrating screen is equipped with real-time monitoring of the screen residue through image recognition technology, which triggers the screen to self-clean in a timely manner and uploads the screening data to the quality traceability system. It should be noted that the intelligent vibrating screen has a mesh range of 180-200.

[0143] An embodiment of the present invention provides a system for preparing a polyester antistatic powder coating, the system comprising:

[0144] A data acquisition module is used to obtain the advancing speed of the pre-melted material;

[0145] Flow analysis module, used to determine the flow inertia factor of the pre-melted material based on the viscosity of the pre-melted material and the heating conditions between different sections;

[0146] Thermal analysis module, used to determine the thermal inertia factor based on the thermal conductivity of the pre-melted material, the effect of the feed particle size on the melting stage, and the expected arrival time of the pre-melted material predicted by the advancing speed;

[0147] The state analysis module is used to match the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different times; based on the delay time difference and the viscosity and propulsion speed of the pre-melted material at the corresponding time, the state change factor of the pre-melted material entering the melting section is determined;

[0148] The determination module is used to determine the total energy fluctuation absorbed by the material due to non-steady-state heat in a time sequence based on the thermal conductivity and state change factor of the pre-melted material; determine the target feeding speed based on the change of the total energy fluctuation in the material advancement length; and determine the optimal feeding speed for preparing polyester antistatic powder coatings in combination with the target feeding speed and the feeding speed reference value.

[0149] Optionally, the transmission medium may be a wired link, such as but not limited to coaxial cable, optical fiber, and digital subscriber line, or a wireless link, such as but not limited to Wireless Fidelity (WIFI), Bluetooth, and mobile device network.

[0150] It should be noted that the device provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above.

[0151] An embodiment of the present invention provides a computer device. Exemplarily, the computer device includes: a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, the computer device can perform any of the aforementioned methods for preparing a polyester antistatic powder coating.

[0152] In addition, an embodiment of the present invention also protects a device, which may include a memory and a processor, wherein the memory stores executable program code, and the processor is used to call and execute the executable program code to execute a method for preparing a polyester antistatic powder coating provided by an embodiment of the present invention.

[0153] In embodiments of the present invention, the device may be divided into functional modules based on the above-described method examples. For example, these modules may correspond to individual functional modules, or two or more functions may be integrated into a single processing module. The integrated modules may be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and represents only a logical functional division. In actual implementation, other division methods may be employed.

[0154] In the case of dividing each module into modules 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 referred to the functional description of the corresponding functional module and will not be repeated here.

[0155] It should be understood that the device provided in the embodiment of the present invention is used to execute the above-mentioned method for preparing a polyester antistatic powder coating, and thus can achieve the same effect as the above-mentioned implementation method.

[0156] When an integrated unit is employed, the device may include a processing module and a storage module. When the device is applied to a device, the processing module can be used to control and manage the device's operations. The storage module can be used to support the device in executing program code, etc. The processing module can be a processor or controller that can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the present disclosure. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processor (DSP) and a microprocessor, etc. The storage module can be a memory.

[0157] In addition, the device provided in an embodiment of the present invention can specifically be a chip, component or module, and the chip may include a connected processor and memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a method for preparing a polyester antistatic powder coating provided in the above embodiment.

[0158] An embodiment of the present invention also provides a computer-readable storage medium, which stores computer program code. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement a method for preparing a polyester antistatic powder coating provided in the above embodiment.

[0159] An embodiment of the present invention further provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement the method for preparing a polyester antistatic powder coating provided in the above embodiment.

[0160] 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 repeated here. Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules as needed, 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.

[0161] The device embodiments described above are merely illustrative. For example, the division into modules or units represents only one logical functional division. Actual implementations may employ alternative divisions, such as combining or integrating multiple units or components into another device, or omitting or disabling certain features. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through an interface, or indirect coupling or communication connection between devices or units may be electrical, mechanical, or otherwise.

[0162] It should also be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or terminal device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or terminal device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or terminal device comprising the element.

[0163] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0164] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0165] The above content is only a specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a polyester antistatic powder coating, characterized in that: The method comprises the following steps: Obtain the advancing speed of the pre-melted material; Determine the flow inertia factor of the pre-melted material based on its viscosity and the heat conditions between different sections; The thermal inertia factor is determined based on the thermal conductivity of the pre-melted material, the effect of the feed particle size in the melting section on the thermal melting, and the expected arrival time of the pre-melted 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-melted material entering the melting section based on the delay time difference and the viscosity and propulsion speed of the pre-melted material at the corresponding time; Based on the thermal conductivity and state change factor of the pre-melted material, the total energy fluctuation absorbed by the material due to non-steady-state heat in time is determined; based on the change of the total energy fluctuation in the material advancement length, the target feeding rate is determined; combined with the target feeding rate and the feeding rate reference value, the optimal feeding rate for preparing polyester antistatic powder coating is determined.

2. The method for preparing a polyester antistatic powder coating according to claim 1, wherein: The method of determining the flow inertia factor of the pre-melted material according to the viscosity of the pre-melted material and the heating conditions between different sections includes: Determining the viscous flow degree of the pre-melted material according to the advancing speed of the pre-melted material and the viscosity of the material in the melting section; The section effect value is determined based on the section length difference between the feeding section and the melting section; Determine the change in melting rate based on the temperature difference between the feeding section and the melting section; The flow inertia factor of the pre-melted material is determined according to the viscous flow degree, the segment effect value and the melting rate change; wherein the viscous flow degree and the segment effect value are both positively correlated with the flow inertia factor, and the melting rate change is negatively correlated with the flow inertia factor.

3. The method for preparing the polyester antistatic powder coating according to claim 1, wherein: The thermal inertia factor is determined based on the thermal conductivity of the pre-melted material, the influence of the particle size of the feed in the melting section on the thermal melting, and the expected arrival time of the pre-melted material predicted by the advancing speed, including: Determine the material property factor based on the material density, specific heat capacity and feed particle size of the pre-melted material; Determine the heating attribute factor based on the expected arrival time and thermal conductivity; The real-time thermal inertia factor is determined based on the material property factor and the heat property factor. The material property factor is positively correlated with the thermal inertia factor, while the heat property factor is negatively correlated with the thermal inertia factor.

4. The method for preparing the polyester antistatic powder coating according to claim 3, wherein: The method for obtaining the expected arrival time is: Taking any moment as the time to be measured, the expected arrival time of the pre-melted material at the time to be measured is determined according to the length of the section from the pre-melted material to the outlet of the melting section at the time to be measured and the advancing speed of the pre-melted material.

5. The method for preparing the polyester antistatic powder coating according to claim 1, wherein: The matching of the flow inertia factor sequence and the thermal inertia factor sequence to obtain the delay time difference at different times includes: The flow inertia factor sequence and the thermal inertia factor sequence are matched using the DTW algorithm. The time difference between each moment in the thermal inertia factor sequence and the corresponding moment in the matched flow inertia factor sequence is calculated to obtain the delay time difference of each moment in the thermal inertia factor sequence.

6. The method for preparing the polyester antistatic powder coating according to claim 1, wherein: The method of determining the state change factor of the pre-melted material entering the melting section according to the delay time difference and the viscosity and advancing speed of the pre-melted material at the corresponding moment includes: Calculating the difference in viscosity of the pre-melted 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 moments corresponding to the elements in the thermal inertia factor sequence and the moments corresponding to the elements in the flow inertia factor sequence; Calculate the average value of the advancing speed of the pre-melted material in the time period between the two moments corresponding to the delay time difference as the overall speed; The state change factor of the pre-melted material entering the melting section is determined based on 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.

7. The method for preparing the polyester antistatic powder coating according to claim 1, wherein: The method of determining the total energy fluctuation absorbed by the material due to non-steady-state heat in a time sequence based on the thermal conductivity and state change factor of the pre-melted material includes: Calculate the product of the mass, specific heat capacity and temperature difference of the pre-melted material to obtain the heat expectation; The total energy fluctuation absorbed by the material due to non-steady-state heat in a time sequence is determined by combining the state change factor and the thermal expectation.

8. The method for preparing the polyester antistatic powder coating according to claim 1, wherein: Determining the target feeding speed according to the change of the total energy fluctuation in the material advancing length includes: Calculate the integral of the square value of the derivative of the total energy fluctuation between the advancement length of the feeding section and the melting section as the target optimization parameter; The target optimization parameter with the smallest value is taken as the best target optimization parameter; The feeding speed at the moment corresponding to the best target optimization parameter is taken as the target feeding speed.

9. The method for preparing the polyester antistatic powder coating according to claim 1, wherein: The method of determining the optimal feeding speed for preparing the polyester antistatic powder coating by combining the target feeding speed and the feeding speed reference value comprises: The average value of the target feeding rate and the feeding rate reference value is taken as the optimal feeding rate for preparing polyester antistatic powder coating.

10. The method for preparing the polyester antistatic powder coating according to claim 1, characterized in that: The method for obtaining the propulsion speed is: Obtain the screw advancement speed, screw groove cross-sectional area and pre-melted material pressure of the screw; Calculate the product of the screw advancement speed and the screw groove cross-sectional area as the intermediate parameter of the pre-melted material; The ratio of the pressure value at the interface between the feeding section and the melting section to the intermediate parameter is used as the filling rate at the interface between the feeding section and the melting section; The filling rate is derived to obtain the advancing speed of the pre-melted material.

Images