Process for the preparation of fluororesin powder coatings

Abstract

The application discloses a fluororesin powder coating preparation process, and belongs to the field of powder coating production, and comprises the following steps: step one, sufficiently mixing raw materials, raw materials for preparing fluororesin powder coating are quantitatively added into a mixing device according to a formula for sufficient mixing and heating; step two, hot extrusion into a film, the mixed and heated mixture is introduced into an extrusion device, and the mixture is extruded into a coating film through extrusion and rolling; step three, stirring the coating film into powder, the extruded coating film is poured into a crushing device, and the extruded coating film is crushed into powder through the crushing device, and the powder is discharged after air separation; and step four, recycling crushed and screened materials, recycling large coating film particles that are not completely powdered and are screened out in the first crushing, and recycling the crushed and discharged materials to improve the yield of finished products; the application is a fluororesin powder coating preparation process with high mixing degree and high finished product proportion.

Description

Technical Field

[0001] This invention mainly relates to the technical field of powder coating production, specifically the preparation process of fluororesin powder coatings. Background Technology

[0002] Fluoropolymer powder coatings refer to powder coatings that use fluoropolymers as the main film-forming substance. Due to the high electronegativity of the introduced fluorine element and the strong carbon-fluorine bond energy, they have particularly superior weather resistance, heat resistance, low-temperature resistance, and chemical resistance. In addition, they have unique non-stick and low friction properties. Fluoropolymer powder coatings are widely used in various fields such as construction, chemical industry, electrical and electronic industry, machinery industry, aerospace industry, and household products, and have a promising market prospect. With the increasing market demand for fluoropolymer powder coatings, there is a need for a high-performance preparation process for fluoropolymer powder coatings.

[0003] According to patent application CN201610110297.6, a powder coating production line includes a mixer, a stirrer, a tablet press, and a powder coating collection device. The mixer and the stirrer are connected by a moving hopper for material transfer. The moving hopper can be installed on the stirrer for stirring. The tablet press and the powder coating collection device are connected by a lifting hopper for material transfer. This powder coating production line can meet the needs of rapid powder coating production.

[0004] The aforementioned patent enables rapid and automated preparation of powder coatings, but it suffers from the drawback of uneven mixing due to mechanical stirring when mixing powdered raw materials. Summary of the Invention

[0005] This invention mainly provides a preparation process for fluoropolymer powder coatings to solve the technical problems mentioned in the background section.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] The preparation process of fluoropolymer powder coatings includes the following steps:

[0008] Step 1: Thoroughly mix the raw materials. The thermosetting trifluorochloroethylene-vinyl ether ester, tetrafluorochloroethylene-vinyl ether ester (FEVE resin), and thermoplastic polyvinylidene fluoride (PVDF resin), pigments, fillers, and additives used to make fluoropolymer powder coatings are added to the mixing device in a quantitative manner according to the formula and thoroughly mixed and heated.

[0009] Step 2: Thermoplastic extrusion film formation. The heated mixture is fed into an extrusion device, and the mixture is extruded into a coating film through extrusion and rolling operations.

[0010] Step 3: The coating film is crushed into powder. The extruded coating film is poured into the crushing device, which crushes the extruded coating film into powder. The small qualified powder coating particles are blown out of the system by the air separation component for discharge.

[0011] Step 4: Circulating crushing and screening. Large pieces of coating film that were not completely pulverized and were screened out during the first crushing are collected by the recycling device and reintroduced into the crushing device for circulating crushing and discharge, thereby improving the yield.

[0012] The mixing device includes a heating furnace and a first blower located at one end of the heating furnace. The extrusion device includes an extrusion box, a pushing component located at one end inside the extrusion box for extruding the mixture, two vertically rotatable rolling rollers located on the other side of the extrusion box for improving the molding quality, and a linkage component located on the outside of the extrusion box for coordinating the pushing component and the rolling rollers. The crushing device includes a crushing box, a crushing component located inside the crushing box, and an air classifier located at the bottom of the crushing box. The recycling device includes a semi-circular bracket, a recycling wheel rotatably installed inside the semi-circular bracket, and a driving component located on one side of the recycling wheel.

[0013] Preferably, the interior of the heating furnace is cylindrical, including a first support at the top of the extrusion box and a feed inlet at the top of the heating furnace. In this preferred embodiment, the cylindrical furnace cavity allows the powdered mixture to be blown around inside the heating furnace.

[0014] Preferably, the first blower includes a support pile disposed at one end of the first bracket. The output end of the first blower is inserted into the heating furnace and faces obliquely downward. In this preferred embodiment, the powdered raw materials are blown up and mixed by the first blower to achieve a more uniform mixing degree.

[0015] Preferably, the crushing component includes several cross-arranged crushing wheels inside the crushing chamber, a roller connected to the crushing wheels at one end of the crushing chamber, a belt connecting all the rollers at the same end, a motor cover fitted over one roller, and a first motor located inside the motor cover and connected to the roller at its actuating end. In this preferred embodiment, the crushing wheels crush the relatively brittle coating film as much as possible, thereby producing powdered coating in the process.

[0016] Preferably, the air separation component includes a second blower located at the bottom of one end of the crushing box near the extrusion box, a screening screen located at the same position at the other end of the crushing box, and a discharge pipe located on the screening screen. In this preferred embodiment, the second blower blows the paint powder of the required size out of the screening screen to ensure that the output quality meets the requirements.

[0017] Preferably, the driving component includes a second motor located at the top of one side of the semi-circular support, a first gear located at the actuating end of the second motor, and a threaded groove located at the middle of the outer side of the recycling wheel, meshing with the first gear. In this preferred embodiment, the threaded groove enables the second motor to drive the recycling wheel to rotate on the semi-circular support, and the recycling wheel pours large pieces of paint back into the crushing device for cyclic crushing, thereby improving the yield.

[0018] Preferably, the pushing component includes several spring telescopic cylinders fixed inside one end of the extrusion box, a long slider located at the actuating end of all the spring telescopic cylinders, and a material discharge trough located at the top of the extrusion box. In this preferred embodiment, the long slider is driven by the spring telescopic cylinders to move below the material discharge trough, thereby realizing the feeding and extrusion operations.

[0019] Preferably, the extrusion box has two semi-enclosed partition boxes symmetrically arranged inside the discharge end, and a parallel plate is arranged outside the discharge end of the extrusion box. The rolling wheel is rotatably connected inside the partition box. In this preferred embodiment, the rolling wheel drives the coating film to be extruded evenly, and the parallel plate sends the extruded coating film into the recycling wheel.

[0020] Preferably, the linkage component includes two internally meshing ratchets located on one side of the extrusion box and connected to the crushing wheel, two second gears parallel to the distal ends of the internally meshing ratchets, a chain connecting each set of internally meshing ratchets and second gears, and two long slots located on one side of the extrusion box. The long slider passes through the long slots and connects to the chain buckle. In this preferred embodiment, the linkage component enables the spring telescopic cylinder to drive the crushing wheel to rotate during extrusion, achieving instantaneous coordinated operation of extrusion and discharge. The internally meshing ratchets ensure that the crushing wheel can only rotate during the extrusion process and cannot reverse when the pushing component retracts, preventing the discharge material from rolling back.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] In this embodiment, a high-powered blower blows air into the cylindrical heating furnace, raising the powdery raw materials. Compared with traditional mechanized stirring methods, this method requires less stirring time and achieves better mixing results.

[0023] The extrusion box's pushing design allows for more precise control of the amount of film formed in a single pass, saving on additional cutting equipment. The rolling rollers and parallel plates ensure a more uniform coating film formation.

[0024] The design of the recycling wheel allows the coating film freshly extruded from the extrusion box and the large pieces of material crushed by the crushing device to be continuously circulated back into the crushing device, greatly improving the finished product ratio.

[0025] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the overall process flow of the present invention.

[0027] Figure 2 This is an isometric view of the overall structure of the present invention;

[0028] Figure 3 This is a schematic diagram of the first part of the device of the present invention;

[0029] Figure 4 This is an enlarged view of part of the structure of the present invention;

[0030] Figure 5 This is a cross-sectional view of the front part of the device of the present invention;

[0031] Figure 6 This is a schematic diagram of the latter part of the device of the present invention;

[0032] Figure 7 This is a cross-sectional view of the crushing device of the present invention.

[0033] Figure Descriptions: 10. Mixing device; 11. Heating furnace; 12. First blower; 20. Extrusion device; 21. Extrusion box; 22. Pushing component; 23. Crushing wheel; 24. Linking component; 30. Crushing device; 31. Crushing box; 32. Crushing component; 33. Air separation component; 40. Recycling device; 41. Semi-circular support; 42. Recycling wheel; 43. Drive component; 111. First support; 112. Feed inlet; 121. Support pile; 321. Crushing wheel; 3 22. Roller; 323. Belt; 324. Motor cover; 325. First motor; 331. Second blower; 332. Screening mesh; 333. Discharge pipe; 431. Second motor; 432. First gear; 433. Threaded groove; 221. Spring telescopic cylinder; 222. Long slider; 223. Discharge chute; 211. Divider box; 212. Parallel plate; 241. Internal meshing ratchet; 242. Second gear; 243. Chain; 244. Long groove; 245. Buckle. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] Example

[0036] Please refer to the appendix carefully. Figure 1 , 2 As shown in Figures 3 and 5, the preparation process of fluororesin powder coatings includes the following steps:

[0037] Step 1: Thoroughly mix the raw materials. The thermosetting trifluorochloroethylene-vinyl ether ester, tetrafluorochloroethylene-vinyl ether ester (FEVE resin), and thermoplastic polyvinylidene fluoride (PVDF resin), pigments, fillers, and additives used to make fluoropolymer powder coatings are added to the mixing device 10 in a quantitative manner according to the formula for thorough mixing and heating.

[0038] Step 2: Thermoplastic extrusion film formation. The heated mixture is fed into the extrusion device 20, and the mixture is extruded into a coating film through extrusion and rolling operations.

[0039] Step 3: The coating film is crushed into powder. The extruded coating film is poured into the crushing device 30. The crushing device 30 crushes the extruded coating film into powder. The small qualified powder coating particles are blown out of the system by the air classifier 33 for discharge.

[0040] Step 4: Circulating crushing and screening. Large pieces of coating film that were not completely pulverized and screened out during the first crushing are collected by the recycling device 40 and reintroduced into the crushing device 30 for circulating crushing and discharge, thereby improving the yield.

[0041] The mixing device 10 includes a heating furnace 11, a first blower 12 located at one end of the heating furnace 11, and an extrusion device 20 including an extrusion box 21, a pushing component 22 located at one end inside the extrusion box 21 for extruding the mixture, two vertically rotatable grinding wheels 23 located on the other side of the extrusion box 21 for improving the molding quality, and a linkage component 24 located on the outside of the extrusion box 21 for coordinating the pushing component 22 and the grinding wheels 23. The crushing device 30 includes a crushing box 31, a crushing component 32 located inside the crushing box 31, and a crushing component 34 located on the other side of the extrusion box 21 for coordinating the pushing component 22 and the crushing wheels 23. The air separation component 33 at the bottom of the crushing box 31, the recycling device 40 including a semi-circular bracket 41, a recycling wheel 42 rotatably installed in the semi-circular bracket 41, a drive component 43 on one side of the recycling wheel 42, the interior of the heating furnace 11 is cylindrical, including a first bracket 111 on the top of the extrusion box 21, a feed inlet 112 on the top of the heating furnace 11, a first blower 12 including a support pile 121 on one end of the first bracket 111, the output end of the first blower 12 is inserted into the heating furnace 11 and faces obliquely downward.

[0042] It should be noted that the feed inlet 112 is funnel-shaped with a wider top and a narrower bottom to prevent the powdery raw materials that have been poured into the heating furnace 11 from being blown up by the blower and overflowing from the inlet. The output end of the first blower 12 blows obliquely downward, which enables the raw materials to roll gently on the bottom of the cylindrical heating furnace 11, resulting in high mixing efficiency.

[0043] Furthermore, the first blower 12 is started to form a strong circulating air in the heating furnace 11, and thermosetting trifluorochloroethylene-vinyl ether ester, tetrafluorochloroethylene-vinyl ether and thermoplastic polyvinylidene fluoride, pigments, fillers and additives are added into the heating furnace 11 in a quantitative manner according to the formula and mixed by being blown up by the circulating air.

[0044] Furthermore, the heating furnace 11 heats the mixture, melting the resinous raw materials and thickening the mixture.

[0045] Please refer to the appendix carefully. Figure 2 , 3 As shown in Figures 4 and 5, the pushing component 22 includes several spring telescopic cylinders 221 fixed inside one end of the extrusion box 21, long sliders 222 located at the actuating ends of all the spring telescopic cylinders 221, a material pouring trough 223 located at the top of the extrusion box 21, two semi-enclosed partition boxes 211 symmetrically arranged inside the discharge end of the extrusion box 21, a parallel plate 212 located outside the discharge end of the extrusion box 21, and a crushing wheel 23 rotatably connected inside the partition box 211. The linkage component 24 includes two internally meshing ratchet wheels 241 located on one side of the extrusion box 21 and connected to the crushing wheel 23, two second gears 242 parallel to the far ends of the internally meshing ratchet wheels 241, a chain 243 connecting each set of internally meshing ratchet wheels 241 and second gears 242, two long grooves 244 located on one side of the extrusion box 21, and a buckle 245 passing through the long grooves 244 and connecting the long slider 222 and the chain 243.

[0046] It should be noted that the length of the extrusion space in the extrusion box 21 is less than the length of the long slider 222. The long groove 244 is located at the end of the moving position of the long slider 222 to prevent the mixture from leaking out. The discharge chute 223 is located directly above the extrusion space in the extrusion box 21. When the long slider 222 is pushed forward, it will close the discharge chute 223; when the long slider 222 is pulled backward, it will open the discharge chute 223.

[0047] Furthermore, the spring telescopic cylinder 221 drives the long slider 222 to pull backward, the discharge chute 223 is opened, and the viscous mixture enters the extrusion box 21. At this time, the long slider 222 pulls the chain 243 backward through the long groove 244 and the buckle 245. The outer ring of the inner meshing ratchet 241 and the second gear 242 reverse, the inner ring of the inner meshing ratchet 241 does not rotate, and the crushing wheel 23 does not move.

[0048] Furthermore, when the spring telescopic cylinder 221 retracts to the bottom, it will push forward, driving the long slider 222 forward. At this time, the long slider 222 closes the pouring trough 223 and stops conveying material. The long slider 222 pulls the chain 243 forward through the long groove 244 and the buckle 245. The internal meshing ratchet 241 and the second gear 242 rotate in the forward direction, and the crushing wheel 23 rotates.

[0049] Furthermore, the long slider 222 continues to move forward, squeezing the viscous mixture into the center of the two rolling rollers 23. The rolling rollers 23 rotate in opposite directions, causing the viscous mixture to be evenly pushed outward, rolling it into a coating film onto the parallel plate 212.

[0050] Please refer to the appendix carefully. Figure 2 , 6 As shown in Figure 7, the crushing component 32 includes several crushing wheels 321 arranged in a cross pattern inside the crushing box 31, a roller 322 connected to the crushing wheels 321 at one end of the crushing box 31, a belt 323 connecting all the rollers 322 at the same end, a motor cover 324 sleeved on one of the rollers 322, and a first motor 325 located inside the motor cover 324 and connected to the roller 322 at its actuating end. The air separation component 33 includes a second blower 331 located at the bottom of one end of the crushing box 31 near the extrusion box 21, a screening screen 332 located at the same position at the other end of the crushing box 31, and a discharge pipe 333 located on the screening screen 332. The driving component 43 includes a second motor 431 located at the top of one side of the semi-circular bracket 41, a first gear 432 located at the actuating end of the second motor 431, and a threaded groove 433 located at the middle of the outer side of the recovery wheel 42 and meshing with the first gear 432.

[0051] It should be noted that the inner ring of the recycling wheel 42 has a groove to prevent materials from falling from the side during the recycling process. The crushing box 31 is semi-cylindrical, and the upper feed opening is slightly smaller than the inner ring diameter of the recycling wheel 42 to ensure that as much material as possible falls into the crushing box 31 when the recycling wheel 42 is recycling it. The length of the coating film squeezed out by the extrusion box 21 is slightly smaller than the width of the groove. It is fed into the recycling wheel 42 by the parallel plate 212. There are two sets of crushing components 32, which are located at both ends of the crushing box 31, so that the adjacent crushing wheels 321 rotate in opposite directions.

[0052] Furthermore, the second motor 431 starts, and through the engagement of the first gear 432 with the threaded groove 433, it drives the recovery wheel 42 to rotate on the semi-circular bracket 41. The coating film inside the recovery wheel 42 falls into the crushing box 31 under the action of gravity.

[0053] Furthermore, the first motor 325 inside the motor cover 324 at both ends of the crushing box 31 is started, and the crushing wheel 321 is driven to rotate and crush the coating film through the roller 322 and the belt 323;

[0054] Furthermore, the second blower 331 is started, blowing the paint powder out from the screen 332 to the discharge pipe 333. The screened paint powder falls into the recycling wheel 42 for recycling and crushing.

[0055] The specific process of this invention is as follows:

[0056] All electrical components in this invention are triggered to operate by a PLC controller, the PLC controller model being "FX3U-16MR".

[0057] At the start of operation, the first blower 12 is activated, creating a strong circulating airflow in the heating furnace 11. Thermosetting trifluorochloroethylene-vinyl ether ester, tetrafluorochloroethylene-vinyl ether, and thermoplastic polyvinylidene fluoride, along with pigments, fillers, and additives, are added sequentially and quantitatively into the heating furnace 11 according to the formula. The mixture is stirred and mixed by the circulating air. The heating furnace 11 heats the mixture, melting the resin raw materials and thickening the mixture. Then, the spring telescopic cylinder 221 drives the long slider 222 to pull backward, opening the discharge chute 22. 3. When the viscous mixture enters the extrusion chamber 21, the long slider 222 pulls the chain 243 backward through the long groove 244 and the connecting buckle 245. The outer ring of the inner meshing ratchet 241 and the second gear 242 reverse, while the inner ring of the inner meshing ratchet 241 does not rotate, and the crushing wheel 23 remains stationary. When the spring telescopic cylinder 221 retracts to the bottom, it pushes forward, driving the long slider 222 forward. At this time, the long slider 222 closes the pouring trough 223, stopping the material conveying. The connecting buckle 245 of the long groove 244 pulls the chain 243 forward, causing the internally meshing ratchet 241 and the second gear 242 to rotate clockwise. The crushing wheel 23 rotates, and the long slider 222 continues to move forward, squeezing the viscous mixture into the center of the two crushing wheels 23. The crushing wheels 23 rotate in opposite directions, causing the viscous mixture to be evenly pushed out, crushing it into a coating film onto the parallel plate 212. Then, the second motor 431 starts, engaging the threaded groove 433 through the first gear 432. The recycling wheel 42 rotates on the semi-circular support 41. The coating film inside the recycling wheel 42 falls into the crushing box 31 under the action of gravity. Finally, the first motor 325 in the motor cover 324 at both ends of the crushing box 31 starts, and drives the crushing wheel 321 to rotate and crush the coating film through the roller 322 and belt 323. The second blower 331 starts, blowing the coating powder out from the screening screen 332 to the discharge pipe 333. The screened coating powder falls into the recycling wheel 42 for cyclic crushing.

[0058] The present invention has been described by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A preparation process for fluororesin powder coatings, characterized in that, Includes the following steps: Step 1: Thoroughly mix the raw materials. The thermosetting trifluorochloroethylene-vinyl ether, tetrafluoroethylene-vinyl ether resin and thermoplastic polyvinylidene fluoride resin, pigments, fillers and additives used to make fluoropolymer powder coatings are added to the mixing device (10) in a quantitative manner according to the formula for thorough mixing and heating. Step 2: Thermoplastic extrusion film formation. The mixed and heated material is introduced into the extrusion device (20), and the material is extruded into a coating film through extrusion and rolling operations. Step 3: The coating film is crushed into powder. The extruded coating film is poured into the crushing device (30). The crushing device (30) crushes the extruded coating film into powder. The small qualified powder coating particles are blown out of the system by the air classifier (33) for discharge. Step 4: Circulating crushing and screening of materials. Large pieces of coating film that were not completely pulverized and screened out during the first crushing are collected by the recycling device (40) and reintroduced into the crushing device (30) for circulating crushing and discharge to improve the yield. The mixing device (10) includes a heating furnace (11) and a first blower (12) located at one end of the heating furnace (11). The extrusion device (20) includes an extrusion box (21), a pushing component (22) located at one end of the extrusion box (21) for extruding the mixture, two vertically rotatable rolling rollers (23) located on the other side of the extrusion box (21) for improving the molding quality, and a linkage component (24) located on the outside of the extrusion box (21) for coordinating the pushing component (22) and the rolling rollers (23). The crushing device (30) includes a crushing box, a crushing component (32) located inside the crushing box, and an air classifier (33) located at the bottom of the crushing box. The recycling device (40) includes a semi-circular bracket (41), a recycling wheel (42) rotatably installed in the semi-circular bracket (41), and a driving component (43) located on one side of the recycling wheel (42). The pushing component (22) includes several spring telescopic cylinders (221) fixed inside one end of the extrusion box (21), a long slider (222) provided at the execution end of all the spring telescopic cylinders (221), and a material pouring groove (223) provided at the top of the extrusion box (21). The extrusion box (21) has two semi-enclosed partition boxes (211) symmetrically arranged inside the discharge end, and a parallel plate (212) is arranged outside the discharge end of the extrusion box (21). The crushing wheel (23) is rotatably connected inside the partition box (211). The linkage component (24) includes two internal meshing ratchet wheels (241) arranged on one side of the extrusion box (21) and connected to the crushing wheel (23), two second gears (242) arranged parallel to the far end of the internal meshing ratchet wheels (241), a chain (243) connecting each set of internal meshing ratchet wheels (241) and second gears (242), two long grooves (244) arranged on one side of the extrusion box (21), and a buckle (245) passing through the long grooves (244) and connecting the long slider (222) and the chain (243).

2. The preparation process of the fluororesin powder coating according to claim 1, characterized in that, The interior of the heating furnace (11) is cylindrical and includes a first support (111) located on the top of the extrusion box (21) and a feed inlet (112) located on the top of the heating furnace (11).

3. The preparation process of the fluororesin powder coating according to claim 1, characterized in that, The crushing component (32) includes several crushing wheels (321) arranged in a cross pattern inside the crushing box, a roller (322) connected to the crushing wheel (321) at one end of the crushing box, a belt (323) connecting all the rollers (322) at the same end, a motor cover (324) sleeved on one of the rollers (322), and a first motor (325) located inside the motor cover (324) and whose execution end is connected to the roller (322).

4. The preparation process of the fluororesin powder coating according to claim 1, characterized in that, The air separation component (33) includes a second blower (331) located at the bottom of one end of the crushing box near the bottom of the extrusion box (21), a screen (332) located at the same position at the other end of the crushing box, and a discharge pipe (333) located at the screen (332).

5. The preparation process of the fluororesin powder coating according to claim 1, characterized in that, The drive component (43) includes a second motor (431) located on the top of one side of the semi-circular bracket (41), a first gear (432) located at the execution end of the second motor (431), and a threaded groove (433) located at the middle of the outer side of the recycling wheel (42) and meshing with the first gear (432).

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