Granulation equipment and granulation process for semiconductor-grade PTFE (Polytetrafluoroethylene) composite granules

Abstract

The invention provides semiconductor-grade PTFE (polytetrafluoroethylene) composite granule granulation equipment and a granulation process, and belongs to the technical field of high polymer material processing. The semiconductor-grade PTFE composite granule granulation equipment comprises a double-screw extruder and a cooling water tank arranged on one side of a discharge port of the double-screw extruder, an isolation barrel is mounted at the top of the cooling water tank, a granule cutting tank is fixedly mounted in the cooling water tank, a water inlet pipe is fixedly mounted at the bottom of the granule cutting tank, and a water outlet pipe is fixedly mounted at the bottom of the water inlet pipe. A discharging pipe is fixedly installed on the grain cutting box, the end, away from the grain cutting box, of the discharging pipe extends out of the cooling water tank, and a grain cutting knife is arranged in the grain cutting box. The semiconductor-grade PTFE composite granule granulation equipment provided by the invention has the advantages that the granule cleanliness and the structural stability can be improved, the processing precision is improved, the defective rate is reduced, and the maintenance is convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material processing, and particularly relates to a semiconductor-grade PTFE composite pellet granulation device and a granulation process. BACKGROUND

[0002] The semiconductor-grade PTFE composite pellet is a granular material made of polytetrafluoroethylene (PTFE) as a matrix, through accurate compounding of nanoscale functional fillers (such as graphene, boron nitride, high-purity ceramic powder, etc.), and an ultra-clean granulation process. Its core characteristics revolve around the stringent requirements of semiconductor manufacturing. On the one hand, it needs to meet the ultra-high purity standard; on the other hand, it needs to break through the performance limitations of pure PTFE through compounding modification, such as adding graphene to improve thermal conductivity, adding ceramic powder to enhance anti-creep performance, etc. To meet the above requirements, the existing granulation process usually follows the core process of "raw material plasticization - strip material forming - cooling and shaping - cutting". The PTFE matrix and functional fillers, additives and other raw materials are forced to mix and plasticize by a double-screw extruder, and are extruded into continuous strip material, which is then cooled and cut according to the cleanliness requirements.

[0003] However, the existing granulation equipment still has the following deficiencies in ensuring the cleanliness and structural stability of the pellets: first, during the extrusion and transportation of the strip material to the cutting equipment, only low-temperature inert gas is used for local pre-cooling of the strip material, and there is a lack of isolation and protection devices, which makes it easy for small dust and suspended particles in the air to penetrate the strip material. At this time, the surface temperature of the strip material is relatively high and has a certain viscosity, which easily adsorbs these small contaminants, resulting in excessive impurity content in the final pellets; second, the existing cooling method lacks a "gradient cooling" design, which easily causes the strip material to be suddenly cooled, thereby causing the material body to crack, the surface to wrinkle or irregularly deform, which not only affects the subsequent cutting precision, but also reduces the structural stability of the pellets.

[0004] Therefore, it is necessary to provide a semiconductor-grade PTFE composite pellet granulation device and a granulation process to solve the above technical problems. SUMMARY

[0005] The technical problem solved by the present application is to provide a semiconductor-grade PTFE composite pellet granulation device and a granulation process that can improve the cleanliness and structural stability of the pellets, improve the processing precision, reduce the waste and defective product rate, and be easy to maintain.

[0006] To solve the above-mentioned technical problems, the present invention provides a semiconductor-grade PTFE composite granulation equipment, comprising a twin-screw extruder and a cooling water tank disposed on one side of the discharge port of the twin-screw extruder. An isolation cylinder is installed on the top of the cooling water tank, a pelletizing box is fixedly installed inside the cooling water tank, a water inlet pipe is fixedly installed at the bottom of the pelletizing box, and a discharge pipe is fixedly installed on the pelletizing box. The end of the discharge pipe away from the pelletizing box extends outside the cooling water tank. A U-shaped frame is fixedly installed on the top of the cooling water tank, and a rotating shaft is rotatably mounted on the U-shaped frame. The bottom end of the rotating shaft extends into the pelletizing box and is fixedly mounted with a pelletizing blade. A pelletizing blade is fixedly installed on the top of the U-shaped frame. A first electric motor, the output end of which is fixedly connected to the top of the rotating shaft; a plurality of equally spaced lower positioning cylinders are fixedly installed on the top of the pelletizing box; a fixed plate is fixedly installed inside the isolation cylinder; a plurality of equally spaced upper guide cylinders are fixedly installed on the top of the fixed plate; a plurality of equally spaced air jet rings are installed on the top of the fixed plate, and each air jet ring is coaxial with the corresponding upper guide cylinder and lower positioning cylinder; a gas supply pipe is fixedly installed on the top of the fixed plate, one end of which extends outside the isolation cylinder; a plurality of connecting pipes are fixedly installed on the top of the gas supply pipe, and each of the connecting pipes is connected to a plurality of air jet rings through pipes. The jet ring has an annular air passage, and the inner wall of the jet ring has multiple air outlets that are distributed in a rotationally symmetrical manner, and the multiple air outlets are connected to the annular air passage.

[0007] Furthermore, inspection and cleaning ports are provided on both outer walls of the isolation cylinder, and inspection and cleaning plates for sealing the inspection and cleaning ports are fixedly installed on both outer walls of the isolation cylinder.

[0008] Preferably, a plurality of fixed tubes are installed through and rotatably on the fixed plate, and a plurality of jet rings are respectively fixedly installed at the top ends of the plurality of fixed tubes, and the fixed tubes are coaxial with the jet rings. A corrugated hose is fixedly installed at the top end of the connecting tube, and the end of the corrugated hose away from the connecting tube is fixedly connected to the jet ring. A gear located below the fixing plate is fixedly sleeved on the outer wall of the fixing tube. A circulating pushing mechanism is installed at the bottom of the fixing plate to cooperate with the gear transmission and drive the fixing tube to reciprocate around its own axis within a preset angle range.

[0009] Preferably, the circulating pushing mechanism comprises a moving strip, a plurality of toothed plates and a second motor, the moving strip is slidingly installed at the bottom of the fixed plate, the plurality of toothed plates are fixedly installed on the moving strip and engaged with the corresponding toothed gears, the second motor is fixedly installed at the bottom of the fixed plate, a cam is fixedly installed on the output end of the second motor, a rotatable connecting rod is rotatably installed at one end of the moving strip close to the second motor, and the rotatable connecting rod is rotatably connected with the cam at the end away from the moving strip.

[0010] Preferably, a C-shaped slide rail is fixedly installed at the bottom of the fixed plate, and the moving strip is slidingly installed in the C-shaped slide rail.

[0011] Further, a receiving lock block is fixedly installed on each of the two side outer walls of the isolation cylinder, and two groups of lock holding mechanisms are installed at the top of the U-shaped frame, and the two groups of lock holding mechanisms are respectively correspondingly matched with the two receiving lock blocks to lock the isolation cylinder.

[0012] Preferably, an arc-shaped through groove is formed in the receiving lock block, a protruding block is integrally formed at the bottom of the receiving lock block, a lock groove is formed in the side wall of the protruding block away from the isolation cylinder, and the lock groove is in communication with the arc-shaped through groove. Each of the lock holding mechanisms comprises a fixed seat, a limiting plug rod, a lock block and a screw rod, the fixed seat is fixedly installed at the top of the U-shaped frame, the limiting plug rod is penetratingly and movably installed in the fixed seat, the end of the limiting plug rod away from the fixed seat extends into the arc-shaped through groove, the lock block is fixedly installed at the bottom of the limiting plug rod, the lock block is located in the lock groove, the screw rod is threadedly installed at the top of the fixed seat, an insertion groove is formed in the outer wall of the limiting plug rod, and a round insertion pin is integrally formed at the bottom end of the screw rod, and the bottom end of the round insertion pin extends into the insertion groove.

[0013] Further, a fan-shaped sliding groove is formed in the outer wall of the limiting plug rod, a rotating limiting block is fixedly installed on the fixed seat, and one end of the rotating limiting block extends into the fan-shaped sliding groove and movably connects with the inner wall of the fan-shaped sliding groove.

[0014] Further, a positioning angle block is fixedly installed at the top of the cooling water tank, and the two inner side walls of the positioning angle block are respectively in contact with the two side outer walls of the isolation cylinder.

[0015] To solve the above problems, the application further provides a semiconductor-grade PTFE composite pellet granulation process, which comprises the following steps: T1: mixing semiconductor-grade PTFE matrix, functional fillers and additives according to a predetermined ratio, and placing them in a clean and dry environment for pretreatment to remove trace moisture and impurities in the raw materials and ensure that the cleanliness of the raw materials meets the requirements of semiconductor grade; T2: The pretreated composite raw materials are sent into the double screw extruder, and through the forced mixing and temperature rising plasticizing effect of the double screw extruder, the components of the raw materials are uniformly dispersed, and at the same time, the plasticized raw materials are extruded into continuous strip-shaped materials, which are conveyed to the isolation cylinder from the discharge port of the double screw extruder; T3: After the strip-shaped materials enter the isolation cylinder, they are guided to the center area of the air ring through the upper guide cylinder, and the external low-temperature nitrogen supply system conveys high-purity low-temperature nitrogen into the air ring through the gas conveying pipe, and the nitrogen is sprayed out through the multiple gas outlets of the air ring to form a ring-shaped gas flow acting on the surface of the strip-shaped materials, thereby realizing the gradual precooling of the strip-shaped materials; T4: The pre-cooled strip-shaped materials enter the cooling water tank, are guided to keep a vertical posture through the lower positioning cylinder, enter the pelletizing box, and the first motor is started to drive the pelletizing knife to rotate in the cooling water, so that the strip-shaped materials are cut into pellets of a predetermined size; T5: The cut pellets are guided out of the cooling water tank through the discharge pipe, and then conveyed to the centrifugal dewatering equipment for dewatering treatment, and after drying, clean and dry semiconductor-grade PTFE composite pellets are obtained.

[0016] Compared with the related art, the semiconductor-grade PTFE composite pelletizing equipment and pelletizing process provided by the application have the following beneficial effects: The semiconductor-grade PTFE composite pelletizing equipment provided by the application, through the setting of the isolation cylinder, on the one hand, can isolate dust and particulate pollutants in the external air, thereby blocking the pollution risk of the strip-shaped materials in the precooling stage from the source; on the other hand, the air ring, gas conveying pipe and corrugated hose etc. components in the isolation cylinder cooperatively constitute a low-temperature nitrogen cooling system, which, in cooperation with the temperature gradient cooling zone formed by the isolation cylinder, realizes the gradual temperature drop of the strip-shaped materials from the extrusion high temperature to the precooling temperature, thereby effectively avoiding the cracking and deformation of the strip-shaped materials caused by sudden cooling; at the same time, the pre-cooled strip-shaped materials are further cooled in the cooling water tank before being cut, and the cooling water can carry away the heat generated by the friction of the pelletizing knife in real time, thereby preventing the PTFE material from adhering to the blade edge and affecting the cutting precision, and the closed cavity of the pelletizing box can also avoid the diffusion of PTFE debris generated in the cutting process, so that the quality of the PTFE composite pellets can be effectively improved under the double protection; The coaxial guiding design of the upper guide cylinder and the lower positioning cylinder provides accurate guidance for the preliminary precooling and subsequent water cooling of the strip-shaped material, the upper guide cylinder ensures that the flexible strip-shaped material just extruded accurately enters the center of the air jet ring, and the lower positioning cylinder can resist the disturbance of water flow to the strip-shaped material, further constrain the strip-shaped material to keep a vertical posture into the cutting area, and avoid cutting deviation caused by material body deviation. The gas conveying pipe stably connects the external high-purity low-temperature nitrogen source, the corrugated hose ensures that the nitrogen has no leakage while meeting the dynamic adjustment demand of the air jet ring, and cooperates with the dynamic adjustment of the circulating pushing mechanism to drive the air jet ring to rotate reciprocatingly around the axis of the strip-shaped material within a preset angle, so that the nitrogen jet covers the full circumferential surface of the strip-shaped material, and ensures uniform precooling of the strip-shaped material, which can greatly reduce the waste and defective product rate caused by cooling differences of the material body. The maintenance sealing plates on both sides of the isolation cylinder adopt a convenient disassembly and assembly structure, opening the sealing plates can directly clean or replace the core components such as the internal air jet ring and the upper guide cylinder, combined with the setting of the locking mechanism and the locked block, after the limiting rod is inserted into the optimal arc groove in the locked block, the lock block is turned and clamped into the lock groove, and then the round pin at the bottom of the screw rod is inserted into the slot on the limiting rod, the rigid locking of the isolation cylinder can be realized, and the reverse operation can be performed when unlocking, which effectively reduces the debugging time after equipment maintenance and improves the overall operation and maintenance efficiency.

[0017] The present application provides a kind of semiconductor grade PTFE composite granule granulation process, which is prepared by the process of raw material cleaning pretreatment-gradient precooling shaping-precision underwater cutting-centrifugal dehydration, which can guarantee the high cleanliness and structural stability of semiconductor grade PTFE composite granules, improve the processing precision and production efficiency of the granules, and efficiently prepare PTFE composite granules that meet the stringent requirements of the semiconductor industry. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The structure schematic diagram of the semiconductor grade PTFE composite granule granulation equipment provided by the present application is shown in the figure. Figure 2 The structure schematic diagram of the cooling water tank is shown in the figure. Figure 1 The cross-sectional structure schematic diagram of the cooling water tank is shown in the figure. Figure 3 The structure schematic diagram of the cooling water tank is shown in the figure. Figure 2 The cross-sectional structure schematic diagram of the cooling water tank is shown in the figure. Figure 4 The structure schematic diagram of the cooling water tank is shown in the figure. Figure 3 The cross-sectional structure schematic diagram of the cooling water tank is shown in the figure. Figure 5 The structure schematic diagram of the cooling water tank is shown in the figure. Figure 4 The cross-sectional structure schematic diagram of the cooling water tank is shown in the figure. Figure 6 The structure schematic diagram of the cooling water tank is shown in the figure. Figure 5 The cross-sectional structure schematic diagram of the cooling water tank is shown in the figure. Figure 7 The structure schematic diagram of the cooling water tank is shown in the figure.Figure 6 Another perspective view of the structure shown in Fig. 1; Figure 8 As shown in Fig. 2, the structure of the fixed tube and the air jet ring is shown in the schematic view. Figure 7 As shown in Fig. 2, the structure of the fixed tube and the air jet ring is shown in the schematic view. Figure 9 As shown in Fig. 3, the top view of the air jet ring is shown in the schematic view. Figure 8 As shown in Fig. 3, the top view of the air jet ring is shown in the schematic view. Figure 10 As shown in Fig. 4, the assembly of the gear and the toothed plate is shown in the schematic view. Figure 7 As shown in Fig. 4, the assembly of the gear and the toothed plate is shown in the schematic view. Figure 11 As shown in Fig. 5, the structure of the cutting box is shown in the schematic view. Figure 3 As shown in Fig. 5, the structure of the cutting box is shown in the schematic view. Figure 12 As shown in Fig. 6, the sectional view of the cutting box is shown in the schematic view. Figure 11 As shown in Fig. 6, the sectional view of the cutting box is shown in the schematic view. Figure 13 As shown in Fig. 7, the schematic view of the locking mechanism and the locked block in the separated state is shown. Figure 3 As shown in Fig. 7, the schematic view of the locking mechanism and the locked block in the separated state is shown. Figure 14 As shown in Fig. 8, the schematic view of the locking mechanism in another perspective view is shown. Figure 13 As shown in Fig. 8, the schematic view of the locking mechanism in another perspective view is shown. Figure 15 As shown in Fig. 9, the schematic view of the screw and the limiting plug in the separated state is shown. Figure 14 As shown in Fig. 9, the schematic view of the screw and the limiting plug in the separated state is shown.

[0019] Reference signs in the drawings: 1. Double-screw extruder; 2. Cooling water tank; 3. Isolation cylinder; 4. U-shaped frame; 5. First motor; 6. Cutting box; 7. Rotating shaft; 8. Cutting knife; 9. Water inlet pipe; 10. Discharge pipe; 11. Lower positioning cylinder; 12. Gas conveying pipe; 13. Fixed plate; 14. Fixed tube; 15. Air jet ring; 151. Annular air channel; 152. Gas outlet; 16. Butt joint pipe; 17. Corrugated hose; 18. Upper guide cylinder; 19. Gear; 20. Moving strip; 21. Toothed plate; 22. Second motor; 23. Rotatable connecting rod; 24. Cam; 25. Fixed seat; 26. Limiting plug; 261. Plug slot; 262. Fan-shaped sliding slot; 27. Locking block; 28. Locked block; 281. Optimal arc through slot; 282. Locking slot; 29. Screw; 30. Rotating limiting block; 31. Positioning angle block. DETAILED DESCRIPTION

[0020] The present application will be further described below in conjunction with the drawings and embodiments.

[0021] First embodiment Please refer to Figures 1-15In the first embodiment of the present application, a semiconductor-grade PTFE composite pelletizing device is provided, which comprises a double-screw extruder 1 and a cooling water tank 2 arranged on one side of the discharge port of the double-screw extruder 1. The double-screw extruder 1 is designed according to the conventional design of the double-screw extruder in the prior art, which is used for forced mixing and temperature plasticizing of the semiconductor-grade PTFE composite raw materials (containing PTFE matrix, functional fillers and additives), to ensure uniform dispersion of each component of the raw materials, and to extrude the plasticized raw materials into continuous strip-shaped materials. The cooling water tank 2 is used for storing cooling water to cool the strip-shaped materials, and is provided with a water inlet connection pipe on the top for connecting with the drain pipe of the centrifugal dehydrator. The top of the cooling water tank 2 is provided with an isolation cylinder 3. The strip-shaped materials pass through the isolation cylinder 3 before entering the cooling water tank 2. On the one hand, the isolation cylinder 3 can isolate dust and particles in the external air from entering its interior, thereby avoiding pollution of the semiconductor-grade PTFE composite strip-shaped materials before subsequent processing. On the other hand, the isolation cylinder 3 is internally provided with a low-temperature nitrogen gas blowing component (i.e. the jet ring 15 mentioned below), which can preliminarily cool the passing strip-shaped materials. At the same time, the closed structure of the isolation cylinder 3 can prevent the low-temperature nitrogen gas from rapidly diffusing into the air, and guide the low-temperature nitrogen gas to be discharged from the top opening thereof from bottom to top. This design forms a gradient cooling zone between the opening and the low-temperature nitrogen gas blowing component in the isolation cylinder 3, thereby progressively cooling the strip-shaped materials, to avoid deformation and cracking of the strip-shaped materials due to sudden cooling. The cooling water tank 2 is fixedly provided with a pelletizing box 6 inside. The pelletizing box 6 is the core cavity for pellet formation, and is immersed in the cooling water. The bottom of the pelletizing box 6 is fixedly provided with a water inlet pipe 9. A guide hopper is welded to the pelletizing box 6, to facilitate smooth discharge of the pellets. The discharge end of the guide hopper is fixedly provided with a discharge pipe 10, the end of the discharge pipe 10 away from the pelletizing box 6 extends outside the cooling water tank 2, and the discharge pipe 10 is connected to the inlet of the suction pump of the centrifugal dehydrator through a pipeline. The top of the cooling water tank 2 is fixedly provided with a U-shaped frame 4. The U-shaped frame 4 is rotatably provided with a rotating shaft 7. The bottom end of the rotating shaft 7 extends into the pelletizing box 6 and is fixedly provided with a pelletizing knife 8. The pelletizing knife 8 performs pelletizing in the water in the pelletizing box 6, to avoid PTFE material adhesion to the blade due to frictional heating. The top of the U-shaped frame 4 is fixedly provided with a first motor 5. The output end of the first motor 5 is fixedly connected to the top end of the rotating shaft 7. The first motor 5 drives the rotating shaft 7 to rotate at high speed, and the rotating shaft 7 drives the pelletizing knife 8 to rotate synchronously. The blade of the pelletizing knife 8 is perpendicular to the conveying direction of the strip-shaped materials, to cut the continuous strip-shaped materials into pellets of a predetermined size. The top of the pelletizing box 6 is fixedly provided with a plurality of equally spaced lower positioning cylinders 11. The lower positioning cylinders 11 are below the water surface, to guide the strip-shaped materials entering the water, effectively avoiding deviation, bending or shaking of the strip-shaped materials under the impact of the water flow, and ensuring that the strip-shaped materials always maintain a vertical state in the cutting area. At the same time, the vertical distance between the bottom of the lower positioning cylinders 11 and the top of the pelletizing knife 8 is maintained between 2-3 mm.The path from positioning constraint to actual cutting of the strip-shaped material is short, which can effectively reduce the slight deformation of the strip-shaped material due to temporary suspension, so that the cut material particles are more regular, the length deviation is smaller, the isolation cylinder 3 is fixedly installed with a fixed plate 13, the top of the fixed plate 13 is fixedly installed with a plurality of upper guide cylinders 18 arranged at equal intervals, the inner wall of which is polished (roughness Ra≤0.8μm), for accurately guiding the strip-shaped material into the center area of the lower gas injection ring 15, the top of the fixed plate 13 is installed with a plurality of gas injection rings 15 arranged at equal intervals, and any one gas injection ring 15 is coaxial with the corresponding upper guide cylinder 18 and lower positioning cylinder 11, the top of the fixed plate 13 is fixedly installed with a gas supply pipe 12, one end of the gas supply pipe 12 extends out of the isolation cylinder 3 and is connected with an external low-temperature nitrogen gas supply system, the top of the gas supply pipe 12 is fixedly installed with a plurality of butt pipes 16, and the plurality of butt pipes 16 are respectively connected with the plurality of gas injection rings 15 through pipelines. The gas injection ring 15 is provided with an annular air channel 151, and a plurality of gas outlets 152 are arranged on the inner wall of the gas injection ring 15 in a rotational symmetry, the plurality of gas outlets 152 are in communication with the annular air channel 151, high-pressure low-temperature nitrogen gas is uniformly distributed from the annular air channel 151 into the plurality of gas outlets 152 and sprayed out through the plurality of gas outlets 152, and directly acts on the surface of the strip-shaped material, so that the temperature of the strip-shaped material is gradually reduced from 200-250℃ after extrusion to 100-120℃ by using the low thermal conductivity and rapid heat absorption characteristics of nitrogen, which can avoid structural stress caused by large temperature difference when the strip-shaped material directly enters the cooling water tank 2, and effectively prevent defects such as cracking, deformation or surface wrinkling of the strip-shaped material.

[0022] In the embodiment, maintenance cleaning openings are formed on the outer walls of the two sides of the isolation cylinder 3, and maintenance sealing plates for sealing the maintenance cleaning openings are fixedly installed on the outer walls of the two sides of the isolation cylinder 3, so that the components on the top of the fixed plate 13 can be directly cleaned, dredged or replaced after the maintenance sealing plates are removed.

[0023] In this embodiment, a plurality of fixed pipes 14 are rotatably installed through the fixed plate 13, a plurality of jet rings 15 are fixedly installed at the top ends of the fixed pipes 14, the fixed pipes 14 and the jet rings 15 are coaxial, a corrugated hose 17 is fixedly installed at the top end of the butt joint pipe 16, the corrugated hose 17 is made of low-temperature-resistant fluorine rubber material and has good flexibility and air tightness, one end of the corrugated hose 17 away from the butt joint pipe 16 is fixedly connected with the jet ring 15, the fixed pipe 14 serves as the rotating shaft of the jet ring 15 and can drive the jet ring 15 to rotate around the strip material axis, the corrugated hose 17 can freely stretch or bend with the rotation of the jet ring 15 while ensuring the nitrogen leakage-free conveying, avoiding the restriction of the pipeline rigidity on the movement of the jet ring 15, and ensuring the continuous cooling process without interruption, and a gear 19 is fixedly sleeved on the outer wall of the fixed pipe 14 and located below the fixed plate 13, a circulating pushing mechanism is installed at the bottom of the fixed plate 13 and used for transmission cooperation with the gear 19 to drive the fixed pipe 14 to reciprocatingly rotate around its axis within a preset angle range, the nitrogen injection angle of the air outlet 152 is dynamically changed through the reciprocating fine adjustment of the jet ring 15, and all areas of the strip material surface can be covered, avoiding the stretch deformation of the strip material caused by local overheating.

[0024] Preferably, the circulating pushing mechanism comprises a moving strip 20, a plurality of toothed plates 21 and a second motor 22, the moving strip 20 is slidingly installed at the bottom of the fixed plate 13, specifically, a C-shaped sliding rail is fixedly installed at the bottom of the fixed plate 13, the moving strip 20 is slidingly installed in the C-shaped sliding rail, the plurality of toothed plates 21 are fixedly installed on the moving strip 20 and engaged with the corresponding gears 19, the second motor 22 is fixedly installed at the bottom of the fixed plate 13, a cam 24 is fixedly installed on the output end of the second motor 22, a rotatable connecting rod 23 is rotatably installed at one end of the moving strip 20 close to the second motor 22, and the other end of the rotatable connecting rod 23 away from the moving strip 20 is rotatably connected with the cam 24, the second motor 22 drives the cam 24 to rotate at a constant speed, the eccentric structure of the cam 24 makes the eccentric shaft do circular motion, and the rotatable connecting rod 23 converts the circular motion of the cam 24 into the push-pull action on the moving strip 20 to drive the moving strip 20 to do reciprocating linear motion along the C-shaped sliding rail, the moving strip 20 drives the toothed plates 21 to synchronously reciprocate, the toothed plates 21 drive the fixed pipe 14 to reciprocatingly rotate around its axis through the engagement transmission with the gears 19, and finally the angle fine adjustment of the jet ring 15 is realized.

[0025] In this embodiment, a locking block 28 is fixedly installed on each of the two side outer walls of the isolation cylinder 3, two groups of locking mechanisms are installed at the top of the U-shaped frame 4, the two groups of locking mechanisms are correspondingly matched with the two locking blocks 28 respectively to realize the locking of the isolation cylinder 3, the position of the isolation cylinder 3 is locked in the normal state to ensure that it does not move, when the components inside the isolation cylinder 3 need to be maintained, the locking of the isolation cylinder 3 can be quickly released through simple operation, and then the isolation cylinder 3 can be taken away from the top of the cooling water tank 2.

[0026] Specifically, the arcuate slot 281 is formed in the locking block 28, the arcuate angle is 270°, the bottom of the locking block 28 is integrally formed with a protrusion, the outer wall of the side of the protrusion away from the isolation cylinder 3 is formed with a locking slot 282, the locking slot 282 is in communication with the arcuate slot 281; any one locking holding mechanism comprises a fixed seat 25, a limiting insertion rod 26, a lock block 27 and a screw rod 29, the limiting insertion rod 26 is matched with the arcuate slot 281, the fixed seat 25 is fixedly installed on the top of the U-shaped frame 4, the limiting insertion rod 26 penetrates and is movably installed on the fixed seat 25, the limiting insertion rod 26 can move horizontally on the fixed seat 25 and can also rotate axially within a certain angle, the end of the limiting insertion rod 26 away from the fixed seat 25 extends into the arcuate slot 281, the lock block 27 is fixedly installed on the bottom of the limiting insertion rod 26, the lock block 27 is matched with the locking slot 282, the lock block 27 is located in the locking slot 282, one end of the limiting insertion rod 26 is inserted into the arcuate slot 281 of the locking block 28, the lock block 27 at the bottom is clamped into the locking slot 282 by rotating the limiting insertion rod 26, at this time, the up-down and left-right displacement of the isolation cylinder 3 is limited, the screw rod 29 is threadedly installed on the top of the fixed seat 25, the outer wall of the limiting insertion rod 26 is formed with an insertion slot 261, the bottom end of the screw rod 29 is integrally formed with a round plug, the bottom end of the round plug extends into the insertion slot 261, the round plug at the bottom end of the screw rod 29 is slowly inserted into the insertion slot 261 of the limiting insertion rod 26 by rotating the screw rod 29 clockwise, the limiting insertion rod 26 is firmly fixed by the thread pre-tightening force, the limiting insertion rod 26 is prevented from loosening when the equipment is running, and rigid locking of the isolation cylinder 3 is realized.

[0027] In the embodiment, the outer wall of the limiting insertion rod 26 is formed with a fan-shaped sliding groove 262, the fixed seat 25 is fixedly installed with a rotating limiting block 30, one end of the rotating limiting block 30 extends into the fan-shaped sliding groove 262 and is movably connected with the inner wall of the fan-shaped sliding groove 262, the cooperation of the fan-shaped sliding groove 262 and the rotating limiting block 30 limits the limiting insertion rod 26 to rotate only 90°, when the limiting insertion rod 26 is pulled out of the arcuate slot 281, the hand lever on the limiting insertion rod 26 is held and rotated 90° upward, the limiting insertion rod 26 cannot be further rotated, the lock block 27 rotates with the limiting insertion rod 26, is in a horizontal state and is located in the long slot of the arcuate slot 281, then the limiting insertion rod 26 is pulled backward, the lock block 27 can be moved in the long slot, and finally the limiting insertion rod 26 can be smoothly pulled out.

[0028] In the embodiment, the top of the cooling water tank 2 is fixedly installed with a positioning angle block 31, the two inner side walls of the positioning angle block 31 are respectively in contact with the two side outer walls of the isolation cylinder 3, the positioning angle block 31 is the “reference coordinate” of the installation of the isolation cylinder 3, when the isolation cylinder 3 is installed, the horizontal position of the isolation cylinder 3 can be determined by the right-angle constraint of the positioning angle block 31, so that the two limiting insertion rods 26 are respectively axially aligned with the two arcuate slots 281.

[0029] In this embodiment: First, start the twin-screw extruder 1, and send the semiconductor-grade PTFE composite raw material into it. The twin-screw extruder 1 forces the raw material to mix and melt through the conventional twin-screw structure, ensuring that the components in the raw material are uniformly dispersed. After the plasticized raw material is extruded into a continuous strip, the strip first enters the isolation cylinder 3 at the top of the cooling water tank 2. During this process, the upper guide cylinder 18 in the isolation cylinder 3 first precisely guides the strip to enter the center area of the air jet ring 15. At the same time, the external low-temperature nitrogen supply system delivers high-pressure low-temperature nitrogen through the gas delivery pipe 12. The nitrogen enters the annular air channel 151 in the air jet ring 15 through the docking pipe 16 and corrugated hose 17 at the top of the gas delivery pipe 12, and is then evenly distributed to the gas outlets 152 on the inner wall of the air jet ring 15, which are distributed symmetrically around the center. Finally, the nitrogen gas is directly applied to the surface of the strip in the form of a ring-shaped gas flow. When the second motor 22 is running, the cam 24 at the output end rotates at a constant speed. The eccentric structure of the cam 24 drives the moving bar 20 to move along the C-shaped slide rail in a reciprocating linear motion through the rotatable connecting rod 23. The toothed plate 21 on the moving bar 20 engages with the gear 19 on the outer wall of the fixed tube 14, which in turn drives the fixed tube 14 and the air jet ring 15 at the top to rotate reciprocally around the axis of the strip within a predetermined angle, dynamically changing the nitrogen injection angle and achieving strip precooling. The closed structure of the isolation cylinder 3 can reduce nitrogen loss, forming a gradient cooling zone between the top opening and the air jet ring 15, where the temperature gradually decreases, thereby gradually cooling the strip. This gradient cooling can avoid structural stress in the strip due to excessive temperature difference, effectively preventing cracking, deformation, or surface wrinkling; After precooling, the strip continues to be transported downward into the cooling water tank 2, where the water inside the tank further cools it. Subsequently, the strip enters the pelletizing box 6, which is entirely immersed in the cooling water of the cooling water tank 2. The lower positioning cylinder 11 at the top of the pelletizing box 6 guides the strip for the second time, ensuring that the strip always maintains a vertical state when entering the cutting area. Then, the first motor 5 at the top of the U-shaped frame 4 is started, driving the rotating shaft 7 to rotate at high speed, which in turn synchronously rotates the pelletizing knife 8. The cutting edge of the pelletizing knife 8 is perpendicular to the direction of strip transport, cutting the continuous strip into pellets of a predetermined size. Since the pelletizing knife 8 operates in cooling water, it can avoid frictional heating that causes PTFE material to adhere to the cutting edge, further ensuring that the pellet cut is neat and the size deviation is small; The cut granules are not scattered due to the isolation of the cutting box 6, and the water in the cutting box 6 is continuously pumped out when the suction pump of the centrifugal dehydrator is running. The water in the cooling water tank 2 enters the cutting box 6 through the water inlet pipe 9, forming a water flow. Under the action of water pressure, the granules enter the discharge pipe 10 with the water flow, and then are transported to the centrifugal dehydrator for dehydration treatment through the pipeline. At the same time, the water inlet connecting pipe at the top of the cooling water tank 2 is connected with the drain pipe of the centrifugal dehydrator, and the cooling water separated during the dehydration process can flow back to the cooling water tank 2, realizing the recycling of the cooling water.

[0030] During the overall operation of the device, the isolation cylinder 3 is kept stable by the locking blocks 28 on both sides and the locking mechanism at the top of the U-shaped frame 4. The limiting insertion rod 26 is inserted into the optimal arc through slot 281 of the locking block 28, and the locking block 27 at the bottom of the limiting insertion rod 26 is clamped into the locking slot 282 on the locking block 28, so as to realize rigid locking of the isolation cylinder 3 and avoid displacement due to device vibration. When the internal components of the isolation cylinder 3 (such as the air injection ring 15 and the upper guide cylinder 18) need to be maintained, the round plug is disengaged from the insertion slot 261 by reversing the screw rod 29, then the limiting insertion rod 26 is rotated to make the locking block 27 exit the locking slot 282, and then the limiting insertion rod 26 is pulled out to release the locking. The isolation cylinder 3 is taken out from the top of the cooling water tank 2, which is convenient to operate.

[0031] Second embodiment: In the second embodiment of the present application, a semiconductor-grade PTFE composite pelletizing process is provided, comprising the following steps: T1: The semiconductor-grade PTFE base material, functional filler and auxiliary agent are mixed according to the preset ratio, and are placed in a clean and dry environment for pretreatment to remove trace moisture and impurities in the raw materials, so as to ensure that the cleanliness of the raw materials meets the requirements of semiconductor grade; T2: The pretreated composite raw material is sent into the double-screw extruder 1, and the forced mixing and temperature rising plasticizing effect of the double-screw extruder 1 makes the components of the raw material uniformly dispersed, and at the same time, the plasticized raw material is extruded into a continuous strip, which is conveyed from the discharge port of the double-screw extruder 1 to the isolation cylinder 3; T3: After the strip enters the isolation cylinder 3, it is guided to the central area of the air injection ring 15 through the upper guide cylinder 18. The external low-temperature nitrogen gas supply system delivers high-purity low-temperature nitrogen gas into the air injection ring 15 through the gas conveying pipe 12. The nitrogen gas is sprayed out through the multiple gas outlets 152 of the air injection ring 15, forming a ring-shaped gas flow acting on the surface of the strip, and realizing progressive precooling of the strip; T4: The pre-cooled strip enters the cooling water tank 2, is guided to maintain a vertical posture by the lower positioning cylinder 11, and enters the cutting box 6. The first motor 5 is started to drive the cutting knife 8 to rotate in the cooling water, and the strip is cut into granules of a predetermined size; T5: the cut granules are guided out of the cooling water tank 2 through the discharge pipe 10, and then transported to a centrifugal dewatering device for dewatering treatment, and then dried to obtain clean and dry semiconductor-grade PTFE composite granules.

[0032] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which is made by using the content of the specification and drawings of the present application, is also included in the patent protection scope of the present application.

Claims

1. A semiconductor-grade PTFE composite pellet granulation apparatus comprising a twin-screw extruder and a cooling water tank provided on one side of a discharge port of the twin-screw extruder, characterized by, The top of the cooling water tank is provided with an isolation cylinder, a pelletizing tank is fixedly installed in the cooling water tank, a water inlet pipe is fixedly installed at the bottom of the pelletizing tank, a discharge pipe is fixedly installed on the pelletizing tank, the end of the discharge pipe away from the pelletizing tank extends out of the cooling water tank, a U-shaped frame is fixedly installed at the top of the cooling water tank, a rotating shaft is rotatably installed on the U-shaped frame, the bottom end of the rotating shaft extends into the pelletizing tank and is fixedly installed with a pelletizing knife, a first motor is fixedly installed at the top of the U-shaped frame, the output end of the first motor is fixedly connected with the top end of the rotating shaft, a plurality of equally spaced lower positioning cylinders are fixedly installed at the top of the pelletizing tank, a fixed plate is fixedly installed in the isolation cylinder, a plurality of equally spaced upper guide cylinders are fixedly installed at the top of the fixed plate, a plurality of equally spaced air jet rings are fixedly installed at the top of the fixed plate, any one of the air jet rings is coaxial with the corresponding upper guide cylinder and lower positioning cylinder, a gas conveying pipe is fixedly installed at the top of the fixed plate, one end of the gas conveying pipe extends out of the isolation cylinder, a plurality of butt joint pipes are fixedly installed at the top of the gas conveying pipe, and the plurality of butt joint pipes are respectively connected with the plurality of air jet rings through pipelines. An annular air channel is formed in the air jet ring, and a plurality of air outlets in rotational symmetry are formed in the inner wall of the air jet ring, and the plurality of air outlets are in communication with the annular air channel.

2. The semiconductor grade PTFE composite pelletization apparatus according to claim 1, wherein, Maintenance and cleaning openings are formed in the outer walls on both sides of the isolation cylinder, and maintenance sealing plates for sealing the maintenance and cleaning openings are fixedly installed on the outer walls on both sides of the isolation cylinder.

3. The semiconductor grade PTFE composite pelletization apparatus of claim 1, wherein, A plurality of fixed pipes are rotatably installed through the fixed plate, a plurality of air jet rings are fixedly installed at the top ends of the fixed pipes, and the fixed pipes and the air jet rings are coaxial, a corrugated hose is fixedly installed at the top end of the butt joint pipe, and the end of the corrugated hose away from the butt joint pipe is fixedly connected with the air jet ring. A gear is fixedly sleeved on the outer wall of the fixed pipe below the fixed plate, a circulating pushing mechanism is installed at the bottom of the fixed plate for transmission cooperation with the gear to drive the fixed pipe to reciprocating rotate around its axis within a preset angle range.

4. The semiconductor grade PTFE composite pelletization apparatus according to claim 3, wherein, The circulating pushing mechanism comprises a moving strip, a plurality of toothed plates and a second motor, the moving strip is slidingly installed at the bottom of the fixed plate, the plurality of toothed plates are fixedly installed on the moving strip and engaged with the corresponding gears, the second motor is fixedly installed at the bottom of the fixed plate, a cam is fixedly installed at the output end of the second motor, a rotatable connecting rod is rotatably installed at the end of the moving strip close to the second motor, and the end of the rotatable connecting rod away from the moving strip is rotatably connected with the cam.

5. The semiconductor grade PTFE composite pelletization apparatus of claim 4, wherein, A C-shaped sliding rail is fixedly installed at the bottom of the fixed plate, and the moving strip is slidingly installed in the C-shaped sliding rail.

6. The semiconductor grade PTFE composite pelletization apparatus of claim 1, wherein, Lock receiving blocks are fixedly installed on the outer walls on both sides of the isolation cylinder, two sets of lock holding mechanisms are installed at the top of the U-shaped frame, and the two sets of lock holding mechanisms are respectively correspondingly matched with the two lock receiving blocks to lock the isolation cylinder.

7. The semiconductor grade PTFE composite pelletization apparatus of claim 6, wherein, An arcuate through slot is formed in the locking block, and a protrusion is integrally formed on the bottom of the locking block, and a locking slot is formed on the outer wall of the protrusion away from the isolation cylinder, and the locking slot is in communication with the arcuate through slot; Any one of the lock holding mechanisms comprises a fixing seat, a limiting insertion rod, a lock block and a screw rod, the fixing seat is fixedly installed on the top of the U-shaped frame, the limiting insertion rod is penetratingly and movably installed on the fixing seat, the end of the limiting insertion rod away from the fixing seat extends into the arcuate through slot, the lock block is fixedly installed on the bottom of the limiting insertion rod, the lock block is located in the locking slot, the screw rod is threadedly installed on the top of the fixing seat, an insertion slot is formed on the outer wall of the limiting insertion rod, and a round insertion pin is integrally formed on the bottom end of the screw rod, and the bottom end of the round insertion pin extends into the insertion slot.

8. The semiconductor grade PTFE composite pelletization apparatus of claim 7, wherein, A fan-shaped sliding groove is formed on the outer wall of the limiting insertion rod, and a rotating limiting block is fixedly installed on the fixing seat, and one end of the rotating limiting block extends into the fan-shaped sliding groove and is movably connected with the inner wall of the fan-shaped sliding groove.

9. The semiconductor grade PTFE composite pelletization apparatus of claim 6, wherein, A positioning angle block is fixedly installed on the top of the cooling water tank, and the two inner side walls of the positioning angle block are respectively in contact with the two outer walls of the isolation cylinder.

10. A process for pelletizing semiconductor grade PTFE composite pellets using the pelletizing apparatus of any one of claims 1 to 9, characterized in that, The method comprises the following steps: T1: The semiconductor-grade PTFE base, functional fillers and additives are mixed according to a preset ratio, and are pretreated in a clean and dry environment to remove trace water and impurities in the raw materials and ensure that the cleanliness of the raw materials meets the requirements of semiconductor grade; T2: The pretreated composite raw materials are fed into a double-screw extruder, and the forced mixing and temperature rising plasticizing effect of the double-screw extruder is used to uniformly disperse each component of the raw materials, and the plasticized raw materials are extruded into a continuous strip, which is conveyed from the discharge port of the double-screw extruder to the isolation cylinder; T3: After the strip enters the isolation cylinder, it is guided to the center area of the air jet ring by the upper guide cylinder, the external low-temperature nitrogen supply system conveys high-purity low-temperature nitrogen into the air jet ring through the gas conveying pipe, the nitrogen is sprayed out through the multiple gas outlets of the air jet ring, and the annular gas flow acts on the surface of the strip to realize progressive precooling of the strip; T4: The pre-cooled strip enters the cooling water tank, is guided to keep a vertical posture by the lower positioning cylinder, enters the pelletizing box, and the first motor is started to drive the pelletizing cutter to rotate in the cooling water to cut the strip into pellets of a preset size; T5: The cut pellets are guided out of the cooling water tank through the discharge pipe, are conveyed to a centrifugal dewatering device for dewatering treatment, and after drying, clean and dry semiconductor-grade PTFE composite pellets are obtained.

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