Sanitary towel PIR film extrusion molding equipment based on regenerated plastic particles

Abstract

The invention discloses sanitary towel PIR film extrusion molding equipment based on regenerated plastic particles, and relates to the technical field of film extrusion molding. Comprising a screw extruder and a feeding barrel installed on a feeding opening in the top of the screw extruder, one side of the screw extruder is connected with a performance gain mechanism through an extrusion pipe, the performance gain mechanism comprises a barrel body, a first material uniformizing plate is fixed in the barrel body, and a plurality of first discharging holes are formed in a plate body of the first material uniformizing plate. The performance gain mechanism is arranged, critical carbon dioxide prepared by the critical carbon dioxide preparation device is injected into the reaction cavity formed by the first material uniformizing plate and the barrel body through the injection pipe, so that the critical carbon dioxide is in contact with molten regenerated plastic, the entanglement concentration of polymer molecular chains is reduced through the swelling effect of supercritical carbon dioxide, and the performance of the molten regenerated plastic is improved. Meanwhile, the free volume is increased by the dissolved gas, so that the motility of molecular chains is enhanced, the viscosity is reduced, the extrusion pressure is reduced, the energy consumption of equipment is reduced, and the product quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of film extrusion molding, and particularly to a sanitary napkin PIR film extrusion molding device based on recycled plastic particles. Background Art

[0002] Recycled plastic particles mainly come from pollution-free scraps, waste materials or unqualified products in the industrial production process, and are made through processes such as recycling, sorting, cleaning, disinfection, crushing, and pelletizing. Making sanitary napkin breathable and leak-proof membranes (PIR) from recycled plastic particles has the advantages of reducing plastic pollution and resource consumption, reducing the production cost of sanitary napkins, and enhancing product competitiveness.

[0003] Chinese invention patent, application publication number: CN115972531A discloses an extruder for a polylactic acid breathable film production line. By placing the feed bin inside the drying and crystallization device for drying and crystallization, then mixing the raw materials through the mixing device, after mixing well, pouring it into the barrel from the inside of the feeding port, after entering the barrel, transporting the product to the inside of the die head through the screw for molding, and then through the molding device, sizing device, corona device, detection device, and finally performing the winding operation through the winding device.

[0004] Chinese invention patent, application publication number: CN118528522A discloses a spiral extruder for breathable film production, which relates to the technical field of plastic molding. Through the formation of a segmented reflux action by the stop block, hard spiral blades, reflux hard pipes, and micro check valves, the heating effect is improved, and it is combined with the heating elements inside the extrusion barrel for preheating action; by adjusting the pitch of the hard spiral blades, it can be adjusted gradually at an equal length to adapt to the optimal spiral extrusion pitch under different raw material processing conditions.

[0005] The existing technologies and the existing sanitary napkin PIR film extrusion molding devices for recycled plastic particles at least still have the following defects in actual applications: First, recycled plastics have a high melt viscosity and poor fluidity due to molecular chain breakage and unstable rheological properties, resulting in a need for higher extrusion pressure, increasing the energy consumption of the equipment. In addition, the shrinkage rate of the products is uneven, the size deviation increases, and it is difficult to meet the requirements of precision machining.

[0006] Second, the recycled plastics have a wide molecular weight distribution, resulting in high shear rate sensitivity and unstable melt viscosity. During the film extrusion molding, the melt pressure distribution in the film cavity is uneven, resulting in uneven thickness of the produced sanitary napkin PIR film. Summary of the Invention

[0007] The purpose of the present invention is to provide a sanitary napkin PIR film extrusion molding device based on recycled plastic particles to solve the problems raised in the above background art.

[0008] To achieve the above object, the present invention provides the following technical solution: A sanitary napkin PIR film extrusion molding device based on recycled plastic particles, including a screw extruder and a feed barrel installed on the top feed port of the screw extruder. One side of the screw extruder is connected with a performance enhancement mechanism through an extrusion pipe. The performance enhancement mechanism includes a barrel body, in which a first material leveling plate is fixed. A plurality of first discharge holes are formed on the plate body of the first material leveling plate. A plurality of first discharge pipes communicating with the first discharge holes are fixed at the bottom end of the first material leveling plate. A first material valve is connected to the pipe body of the first discharge pipe; A plurality of injection pipes are fixedly communicated with the top of the barrel body. The injection pipes are connected with a critical carbon dioxide preparation device. The critical carbon dioxide prepared by the critical carbon dioxide preparation device is injected into the reaction cavity formed by the first material leveling plate and the barrel body through the injection pipes; A circulation pipe is fixedly communicated with the bottom of the barrel body. One side of the circulation pipe is connected with a film extrusion die head. The sanitary napkin PIR film is extruded through the film extrusion die head; The film extrusion die head includes a die shell. A top pressure sensor is fixed on the inner wall of the top of the die shell. Side pressure sensors are fixed on the inner wall of at least one side of the die shell; A top lip plate and a bottom lip plate are respectively arranged at the top and bottom of the film outlet side of the die shell. An outlet gap with a triangular cross-section is formed between the top lip plate and the bottom lip plate. An activity groove is formed on the top of the die shell. A vertically extending block is integrally formed on the top of the top lip plate. The vertically extending block is adapted to the activity groove. A damping block with a triangular cross-section is arranged in the die shell. A driving mechanism is arranged between the damping block and the vertically extending block.

[0009] Furthermore, a cavity is formed on the outer side of the barrel body. A heating wire is arranged in the cavity. The inner cavity of the barrel body is heated by the heating wire.

[0010] Furthermore, a second material leveling plate is also fixed in the barrel body. A plurality of second discharge holes are formed on the second material leveling plate. A plurality of second discharge pipes communicating with the second discharge holes are fixed at the bottom end of the second material leveling plate. A second material valve is connected to the pipe body of the second discharge pipe; A gas precipitation cavity is formed between the first material leveling plate and the second material leveling plate; A U-shaped air pipe communicated with the gas precipitation cavity is fixed on the outer side of the barrel body. A suction pipe and a connecting pipe are fixedly communicated with the side of the U-shaped air pipe. Solenoid valves are connected to the pipe bodies of the suction pipe and the connecting pipe. One side of the suction pipe is connected with a suction pump.

[0011] Furthermore, a vertical cylinder is formed at the bottom of the barrel body. A rotating shaft is movably connected to the top of the vertical cylinder. A first motor is fixed at the bottom end of the vertical cylinder. The output end of the first motor is fixed to the end of the rotating shaft. A spiral blade is fixed on the shaft body of the rotating shaft. The circulation pipe is fixedly communicated with the bottom of the vertical cylinder.

[0012] Further, a first flow guide plate and a second flow guide plate are arranged inside the formwork. A plurality of first flow guide holes and second flow guide holes are respectively formed in the plates of the first flow guide plate and the second flow guide plate, and the first flow guide holes and the second flow guide holes are staggered.

[0013] Further, a trapezoidal cavity is formed between the first flow guide plate and the formwork.

[0014] Further, an arc-shaped buffer block is arranged in the trapezoidal cavity, and the arc-shaped buffer block is located on one side of the flow pipe; A plurality of through grooves are formed at the bottom of the formwork. A plurality of T-shaped plates are fixed at the bottom end of the arc-shaped buffer block. The T-shaped plates are adapted to the through grooves, and springs are fixed between the side walls of the through grooves and the T-shaped plates.

[0015] Further, extension plates are formed on both sides of the first flow guide plate. Sliding grooves are formed on both sides of the formwork. The extension plates are adapted to the sliding grooves. Electric telescopic rods are fixed on both sides of the formwork. The telescopic ends of the electric telescopic rods extend into the sliding grooves, and their ends are fixed to the extension plates. When the electric telescopic rods expand and contract, they drive the first flow guide plate to move, so as to adjust the distance between the first flow guide plate and the second flow guide plate; A viscosity detector is fixed on the side of the formwork, and the viscosity of the molten recycled plastic in the trapezoidal cavity is detected by the viscosity detector.

[0016] Further, the driving mechanism includes a driving box, a guide rod that is movably inserted into the damping block, and a lead screw that is movably screwed to the damping block. First support frames are movably connected to the rods of the guide rod and the lead screw; A first movable rod and a screw rod are movably connected to the top of the formwork. The screw rod is movably screwed to the vertically extending block. A first gear pair is arranged between the lead screw and the first movable rod. A plurality of second support frames distributed horizontally are fixed at the top end of the formwork. A second movable rod, a middle roller and a third movable rod are respectively movably connected to the second support frames. The middle roller is located between the second movable rod and the third movable rod; A third gear pair is arranged between the second movable rod and the screw rod, and a second gear pair is arranged between the third movable rod and the first movable rod; Guide blocks are fixed on the rods between the middle roller and the second movable rod and on the rods between the middle roller and the third movable rod. Annular sleeve blocks are movably inserted into the rods between the middle roller and the second movable rod and on the rods between the middle roller and the third movable rod. A plurality of guide grooves adapted to the guide blocks are formed inside the annular sleeve blocks; Grooves are formed on the outer sides of the annular sleeve blocks. Forks are movably inserted into the grooves. A vertical plate is fixed at the top end of the formwork. A double-headed electric telescopic rod is fixed at the top of the vertical plate. The two telescopic rods of the double-headed electric telescopic rod are respectively fixed to the two forks; A worm gear is fixed on the shaft body of the middle roller. A worm is movably connected to the drive box. The worm is meshed with the worm gear. A second motor is fixed on the outside of the drive box, and the output end of the second motor is fixed to the end of the worm.

[0017] Furthermore, a ranging sensor is fixed on the outside of the top lip plate, and a receiver is fixed on the outside of the bottom lip plate. The width of the discharge gap is detected by the ranging sensor and the receiver.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The sanitary napkin PIR film extrusion molding equipment based on recycled plastic particles is provided with a performance enhancement mechanism. The critical carbon dioxide prepared by the critical carbon dioxide generator is injected into the reaction cavity formed by the first material homogenizing plate and the barrel through the injection pipe, so as to contact the molten recycled plastic. Through the swelling effect of supercritical carbon dioxide, the entanglement concentration of polymer molecular chains is reduced. At the same time, the dissolved gas increases the free volume, enhances the molecular chain mobility, decreases the viscosity, reduces the extrusion pressure, reduces the equipment energy consumption, and improves the product quality.

[0019] At the same time, an adjustable top lip plate, a damping block and a driving mechanism are provided. When the top pressure sensor exceeds the set value, the top lip plate is driven to move downward by the driving mechanism, so as to narrow the discharge gap to compensate for the increase in the discharge gap under high pressure and ensure that the thickness of the sanitary napkin PIR film remains unchanged. When the pressure of the molten plastic on both sides of the discharge gap is less than the pressure of the molten plastic in the middle of the discharge gap, there is a difference between the pressure value detected by the side pressure sensor and the pressure value detected by the top pressure sensor. The damping block is driven to contract towards the center of the discharge gap by the driving mechanism, increasing the flow channel resistance in the center of the discharge gap, forcing the melt to diffuse to both sides, compensating for the uneven distribution of the melt pressure, and avoiding the reduction of the product quality due to uneven thickness of the sanitary napkin PIR film.

[0020] In addition, a second material homogenizing plate, an air extraction pipe and a connecting pipe are provided. When the air pump is started, the air pressure in the gas precipitation cavity decreases, promoting the precipitation of bubbles in the melt. Finally, the precipitated gas is pumped out of the gas precipitation cavity through the air extraction pipe, effectively reducing the amount of bubbles in the melt and improving the product quality.

[0021] At the same time, a vertical cylinder, a rotating shaft and a spiral blade are formed at the bottom of the barrel. The melt enters the bottom of the barrel along the second discharge pipe. The controller controls the first motor to start. Driven by the spiral blade, the melt enters the flow pipe at a certain speed and pressure, thus increasing the production efficiency.

[0022] In addition, a first deflector, a second deflector and a trapezoidal cavity are provided, which can make the melt flow more smoothly, reduce the fluid resistance, help to increase the extrusion speed, reduce the energy consumption. Secondly, the trapezoidal cavity can prevent the pressure in the middle of the die shell from being greater than that on both sides, improving the product quality. Moreover, the first diversion holes and the second diversion holes are staggered, enabling the melt to enter the cavity formed by the first deflector and the second deflector under a certain pressure, further reducing the pressure fluctuation of the melt in the die shell.

[0023] In addition, arc-shaped buffer blocks are arranged in the trapezoidal cavity, which can promote the melt to flow along both sides of the trapezoidal cavity, enabling the melt to enter the trapezoidal cavity evenly. In addition, the spring can buffer the melt flowing out of the flow pipe, preventing the melt from causing excessive pressure fluctuation in the trapezoidal cavity due to excessive pressure fluctuation, improving the product quality.

[0024] Moreover, a viscosity detector and a movable first deflector are provided to adjust the distance between the first deflector and the second deflector according to the viscosity of the melt, so as to reduce the shear stress in the flow channel, avoid the melt from rupturing or carbonizing due to excessive local pressure and increase the shear rate when the melt passes through, reducing the formation of eddy currents, thereby keeping the pressure in the inner cavity of the die shell stable and improving the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the left axonometric view of the present invention; Figure 2 is the right rear axonometric view of the present invention; Figure 3 is the half-sectional view of the present invention; Figure 4 is the axonometric view of the film extrusion die head of the present invention; Figure 5 is the bottom view of the film extrusion die head of the present invention; Figure 6 is the first cross-sectional view of the film extrusion die head of the present invention; Figure 7 is the second cross-sectional view of the film extrusion die head of the present invention; Figure 8 is the detailed view of the driving mechanism of the present invention.

[0026] In the figure: 1. Screw extruder; 101. Feeding barrel; 102. Extrusion pipe; 2. Performance gain mechanism; 201. First material leveling plate; 202. First discharge pipe; 203. First material valve; 204. Gas precipitation chamber; 205. Vertical cylinder; 206. Rotating shaft; 207. First motor; 208. Flow pipe; 3. Membrane extrusion die head; 301. Die shell; 4. Heating wire; 5. Injection pipe; 601. U-shaped air pipe; 602. Exhaust pipe; 603. Solenoid valve; 7. Top pressure sensor; 8. Side pressure sensor; 9. Arc buffer block; 901. T-shaped plate; 902. Spring; 10. First guide plate; 1001. First guide hole; 11. Second guide plate; 1101. Second guide hole; 12. Electric telescopic rod; 13. Viscosity detector; 14. Top lip plate; 141. Vertically extending block; 15. Distance measuring sensor; 16. Discharge gap; 17. Damping block; 171. Guide rod; 172. First support frame; 18. Driving mechanism; 181. Lead screw; 182. First movable rod; 183. First gear pair; 184. Middle roller; 185. Second movable rod; 186. Second gear pair; 187. Screw; 188. Third gear pair; 189. Ring-shaped sleeve block; 1810. Fork; 1811. Double-headed electric telescopic rod; 1812. Worm gear; 1813. Worm; 19. Second support frame. Detailed implementation mode

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0028] Recycled plastic particles mainly come from pollution-free scraps, waste materials or unqualified products in the industrial production process, and are made through processes such as recycling, sorting, cleaning, disinfection, crushing, and granulation. Making recycled plastic particles into a sanitary napkin breathable leak-proof film (PIR) has the advantages of reducing plastic pollution and resource consumption, reducing the production cost of sanitary napkins, and enhancing product competitiveness.

[0029] Embodiment 1: As Figures 1 - 4 and Figures 6 - 8 shown, the present invention provides a technical solution: a sanitary napkin PIR film extrusion and forming device based on recycled plastic particles, including a controller, a screw extruder 1, and a feeding barrel 101 installed at the top feeding port of the screw extruder 1. The feeding barrel 101 contains molten recycled plastic, and the screw extruder 1 transports the molten recycled plastic. A performance gain mechanism 2 is connected to the screw extruder 1 through an extrusion pipe 102 on one side. Among them, as Figures 1 - 3As shown, the performance gain mechanism 2 includes a barrel body. A first material leveling plate 201 is fixed inside the barrel body. A plurality of first discharge holes arranged in an annular array are formed on the plate body of the first material leveling plate 201. A plurality of first discharge pipes 202 communicating with the first discharge holes are fixed at the bottom end of the first material leveling plate 201. And a first material valve 203 is connected to the pipe body of the first discharge pipe 202. To prevent the molten recycled plastic from solidifying due to temperature reduction during extrusion, a cavity is formed on the outer side of the barrel body, and a heating wire 4 is arranged in the cavity. The inner cavity of the barrel body is heated by the heating wire 4.

[0030] A plurality of injection pipes 5 are fixedly connected to the top of the barrel body. The injection pipes 5 are connected to a critical carbon dioxide preparation device. The critical carbon dioxide prepared by the critical carbon dioxide preparation device is injected into the reaction cavity formed by the first material leveling plate 201 and the barrel body through the injection pipes 5. A circulation pipe 208 is fixedly connected to the bottom of the barrel body. A membrane extrusion die head 3 is connected to one side of the circulation pipe 208. The sanitary napkin PIR film is extruded through the membrane extrusion die head 3.

[0031] As Figures 3 - 4 、 Figures 6 - 8 shown, the membrane extrusion die head 3 includes a die shell 301. A top pressure sensor 7 is fixed on the inner wall of the top of the die shell 301. At least one side inner wall of the die shell 301 is fixed with a side pressure sensor 8. In this solution, the side pressure sensor 8 is set to one. The top pressure sensor 7 and the side pressure sensor 8 can be piezoelectric ceramic sensors. As Figure 3 shown, the top pressure sensor 7 and the side pressure sensor 8 are arranged longitudinally along the die shell 301. The pressure of the molten recycled plastic flowing in the inner cavity of the die shell 301 and the pressure of the molten recycled plastic flowing on the side of the die shell 301 are respectively detected by the top pressure sensor 7 and the side pressure sensor 8.

[0032] As Figure 7 shown, a top lip plate 14 and a bottom lip plate are respectively arranged at the top and bottom of the film outlet side of the die shell 301. An outlet gap 16 with a triangular cross-section is formed between the top lip plate 14 and the bottom lip plate. The outlet gap 16 gradually converges along the film outlet of the die shell 301. An activity groove is formed at the top of the die shell 301. A vertical extension block 141 is integrally formed at the top of the top lip plate 14. And the vertical extension block 141 is adapted to the activity groove. A damping block 17 with a triangular cross-section is arranged in the die shell 301. The convergence direction of the damping block 17 is opposite to the convergence direction of the outlet gap 16. A driving mechanism 18 is arranged between the damping block 17 and the vertical extension block 141. The vertical extension block 141 and the damping block 17 are driven to move through the driving mechanism 18, so as to realize the adjustment of the width of the outlet gap 16 and the pressure of the molten recycled plastic on both sides of the outlet gap 16.

[0033] As Figure 7 and Figure 8As shown in the figure, the driving mechanism 18 includes a driving box, a guide rod 171 that is movably inserted into the damping block 17, and a lead screw 181 that is movably screwed to the damping block 17. First support frames 172 are movably connected to the rod bodies of the guide rod 171 and the lead screw 181. The bottom ends of the first support frames 172 are fixed to the bottom inner wall of the mold shell 301. A first movable rod 182 and a screw rod 187 are movably connected to the top of the mold shell 301. The screw rod 187 is movably screwed to the vertical extension block 141. When the screw rod 187 rotates, it drives the vertical extension block 141 and the top lip plate 14 to move up and down, so as to adjust the width of the discharging gap 16. A first gear pair 183 is arranged between the lead screw 181 and the first movable rod 182. A plurality of second support frames 19 distributed horizontally are fixed to the top end of the mold shell 301. In this solution, the number of the second support frames 19 is set to three. A second movable rod 185, a middle roller 184, and a third movable rod are respectively movably connected to the three second support frames 19. The middle roller 184 is located between the second movable rod 185 and the third movable rod. A third gear pair 188 is arranged between the second movable rod 185 and the screw rod 187. A second gear pair 186 is arranged between the third movable rod and the first movable rod 182. The gear pairs in this solution are all bevel gear pairs, and their gear ratios are not limited in this solution.

[0034] Guide blocks are fixed to the rod bodies between the middle roller 184 and the second movable rod 185 and between the middle roller 184 and the third movable rod. Ring-shaped sleeve blocks 189 are movably inserted into the rod bodies between the middle roller 184 and the second movable rod 185 and between the middle roller 184 and the third movable rod. A plurality of guide grooves adapted to the guide blocks are provided inside the ring-shaped sleeve blocks 189. Grooves are provided on the outer sides of the ring-shaped sleeve blocks 189. Forks 1810 are movably inserted into the grooves. A vertical plate is fixed to the top end of the mold shell 301. A double-headed electric telescopic rod 1811 is fixed to the top of the vertical plate. The two telescopic rods of the double-headed electric telescopic rod 1811 are respectively fixed to the two forks 1810. A worm gear 1812 is fixed to the shaft body of the middle roller 184. A worm 1813 is movably connected to the driving box. The other end of the worm 1813 is movably connected to the vertical plate. The worm 1813 meshes with the worm gear 1812. A second motor is fixed to the outside of the driving box. The output end of the second motor is fixed to the end of the worm 1813. It can be known that in this solution, the transmission method of meshing the worm 1813 with the worm gear 1812 is adopted. The reason is that the meshing of the worm 1813 with the worm gear 1812 can realize the self-locking property of the worm 1813, thereby preventing the disorderly rotation of the second movable rod 185 or the third movable rod, and further preventing the misadjustment of the top lip plate 14 and the damping block 17.

[0035] Specifically, the molten recycled plastic enters the barrel through the feed hopper 101, the screw extruder 1, and the extrusion pipe 102. The critical carbon dioxide prepared by the critical carbon dioxide generator is injected into the reaction chamber formed by the first homogenizing plate 201 and the barrel through the injection pipe 5, so as to come into contact with the molten recycled plastic. The entanglement concentration of polymer molecular chains is reduced through the swelling effect of supercritical carbon dioxide. At the same time, the dissolved gas increases the free volume, enhancing the molecular chain mobility and decreasing the viscosity. After a period of time, the first material valve 203 is opened, and the molten recycled plastic enters the inner cavity of the mold shell 301 through the flow pipe 208. The pressure of the molten recycled plastic flowing in the inner cavity of the mold shell 301 and the pressure of the molten recycled plastic flowing on the side of the mold shell 301 are respectively detected by the top pressure sensor 7 and the side pressure sensor 8. The detection period can be 3 - 10 seconds. When the top pressure sensor 7 exceeds the set value, the discharge gap 16 will increase. At this time, the controller controls the double-headed electric telescopic rod 1811 on one side of the middle roller 184 and the third movable rod to contract, and the double-headed electric telescopic rod 1811 on the other side to extend. Thus, the annular sleeve block 189 is driven by the fork 1810 to move to one side of the middle roller 184 and the other annular sleeve block 189 is driven by the fork 1810 to move between the middle roller 184 and the second movable rod 185. The controller controls the second motor to start, and drives the screw 187 to rotate through the third gear pair 188, driving the top lip plate 14 to move downward, thereby reducing the discharge gap 16 to compensate for the increase in the discharge gap 16 under high pressure and ensuring the constant thickness of the sanitary napkin PIR film. If the pressure of the molten plastic on both sides of the discharge gap 16 is less than the pressure of the molten plastic in the middle of the discharge gap 16, there is a difference between the pressure value detected by the side pressure sensor 8 and the pressure value detected by the top pressure sensor 7. At this time, the controller controls the double-headed electric telescopic rod 1811 on one side of the middle roller 184 and the third movable rod to extend, and the double-headed electric telescopic rod 1811 on the other side to contract. Thus, the annular sleeve block 189 is driven by the fork 1810 to move to one side of the middle roller 184 and the other annular sleeve block 189 is driven by the fork 1810 to move between the middle roller 184 and the third movable rod. The controller controls the second motor to start, and drives the lead screw 181 to rotate through the second gear pair 186 and the first gear pair 183. The damping block 17 contracts towards the center of the discharge gap 16, increasing the flow channel resistance at the center of the discharge gap 16, forcing the melt to diffuse to both sides, compensating for the uneven distribution of melt pressure, and avoiding the reduction of product quality due to uneven thickness of the sanitary napkin PIR film.

[0036] It should be noted that by establishing the adjustment priority through the prior art, when the pressure detected by the top pressure sensor 7 is greater than the threshold value and the difference between the pressure value detected by the side pressure sensor 8 and the pressure value detected by the top pressure sensor 7 is greater than the set value at the same time, the width of the discharge gap 16 is preferentially adjusted, and then the position of the damping block 17 is adjusted. In addition, to facilitate the rapid adjustment of the position of the top lip plate 14, a ranging sensor 15 is fixed on the outer side of the top lip plate 14, and a receiver is fixed on the outer side of the bottom lip plate. The width of the discharge gap 16 is detected by the ranging sensor 15 and the receiver.

[0037] Embodiment 2: On the basis of Embodiment 1, as Figure 3 shown, a second material leveling plate is further fixed in the barrel body. A plurality of second discharge holes are formed in the second material leveling plate. A plurality of second discharge pipes communicating with the second discharge holes are fixed at the bottom end of the second material leveling plate. A second material valve is connected to the pipe body of the second discharge pipe. A gas precipitation chamber 204 is formed between the first material leveling plate 201 and the second material leveling plate. A U-shaped air pipe 601 communicating with the gas precipitation chamber 204 is fixed on the outer side of the barrel body. An air extraction pipe 602 and a communication pipe are fixedly communicated with the side surface of the U-shaped air pipe 601. Solenoid valves 603 are connected to the pipe bodies of the air extraction pipe 602 and the communication pipe. One side of the air extraction pipe 602 is connected to an air extraction pump.

[0038] Specifically, to meet the production requirements, a modifier or other additives are added to the recycled plastic particles, and through procedures such as stirring and mixing, a certain amount of bubbles are contained in the melt. To prevent the existence of bubbles from affecting the product quality, in this embodiment, after the reaction between the critical carbon dioxide and the melt is completed, the first material valve 203 is opened, and the melt enters the gas precipitation chamber 204. The air pump is started, the air pressure in the gas precipitation chamber 204 is reduced, which promotes the precipitation of bubbles in the melt. Finally, the precipitated gas is extracted from the gas precipitation chamber 204 through the air extraction pipe 602, thereby effectively reducing the amount of bubbles in the melt and improving the product quality.

[0039] Embodiment 3: On the basis of Embodiment 1 or Embodiment 2, as Figure 3 shown, a vertical cylinder 205 is formed at the bottom of the barrel body. A rotating shaft 206 is movably connected to the top of the vertical cylinder 205. A first motor 207 is fixed at the bottom end of the vertical cylinder 205. The output end of the first motor 207 is fixed to the end of the rotating shaft 206. A spiral blade is fixed on the shaft body of the rotating shaft 206. The flow pipe 208 is fixedly communicated with the bottom of the vertical cylinder 205.

[0040] In this way, after the gas in the melt is discharged, the solenoid valve 603 and the second material valve on the connecting pipe are opened to make the air pressure in the gas precipitation chamber 204 equal to the atmospheric pressure. Under the action of the weight of the melt, the melt enters the bottom of the barrel along the second discharge pipe. The controller controls the first motor 207 to start, and driven by the spiral blade, the melt enters the flow pipe 208 at a certain speed and pressure, thereby increasing the production efficiency.

[0041] Example 4: As Figure 4 、 Figure 6 and Figure 7 shown, on the basis of Example 1, Example 2 or Example 3, a first guide plate 10 and a second guide plate 11 are arranged in the mold shell 301. A plurality of first guide holes 1001 and second guide holes 1101 are respectively formed on the plates of the first guide plate 10 and the second guide plate 11, and the first guide holes 1001 and the second guide holes 1101 are staggered. In addition, a trapezoidal cavity is formed between the first guide plate 10 and the mold shell 301.

[0042] It can be understood that the setting of the trapezoidal cavity, firstly, can make the melt flow more smoothly, reduce the fluid resistance, help to improve the extrusion speed and reduce the energy consumption. Secondly, during the extrusion molding process, it helps to dissipate heat quickly and prevent the melt performance from decreasing due to local overheating. Moreover, the setting of the trapezoidal cavity can prevent the pressure in the middle of the mold shell 301 from being greater than the pressure on both sides, improving the product quality.

[0043] It can also be understood that the first guide holes 1001 and the second guide holes 1101 are staggered, which can make the melt enter the cavity formed by the first guide plate 10 and the second guide plate 11 at a certain pressure, further reducing the pressure fluctuation of the melt in the mold shell 301.

[0044] Example 5: On the basis of Example 4, as Figure 5 and Figure 6 shown, an arc-shaped buffer block 9 is arranged in the trapezoidal cavity, and the arc-shaped buffer block 9 is located on one side of the flow pipe 208. In addition, a plurality of through grooves are formed at the bottom of the mold shell 301. A plurality of T-shaped plates 901 are fixed at the bottom end of the arc-shaped buffer block 9, and the T-shaped plates 901 are adapted to the through grooves. Springs 902 are fixed between the side walls of the through grooves and the T-shaped plates 901. The plates of the T-shaped plates 901 are in contact with the bottom plate of the mold shell 301 to prevent the melt from leaking through the gap between the plates of the T-shaped plates 901 and the bottom plate of the mold shell 301.

[0045] The setting of the arc-shaped buffer block 9 can promote the melt to flow along both sides of the trapezoidal cavity, making the melt enter the trapezoidal cavity evenly. In addition, the melt flowing out of the flow pipe can be buffered by the spring 902 to prevent the pressure in the trapezoidal cavity from fluctuating too much due to excessive pressure fluctuation, improving the product quality.

[0046] Embodiment Six: On the basis of Embodiments Two to Five, as Figure 6 shown, extension plates are formed on both sides of the first deflector 10, sliding grooves are formed on both sides of the die shell 301, and the extension plates are adapted to the sliding grooves. Electric telescopic rods 12 are fixed on both sides of the die shell 301. The telescopic ends of the electric telescopic rods 12 extend into the sliding grooves, and their ends are fixed to the extension plates. When the electric telescopic rods 12 expand and contract, they drive the first deflector 10 to move, so as to adjust the distance between the first deflector 10 and the second deflector 11. A viscosity detector 13 is fixed on the side of the die shell 301 to detect the viscosity of the molten recycled plastic in the trapezoidal cavity.

[0047] Specifically, since the melt viscosities of recycled materials from different sources may vary greatly due to different degrees of thermal degradation, when the viscosity value detected by the viscosity detector 13 is greater than the set value, the electric telescopic rod 12 is controlled to contract by the controller, and the distance between the first deflector 10 and the second deflector 11 increases, which can reduce the shear stress in the flow channel and avoid melt rupture or carbonization caused by excessive local pressure. When the viscosity value detected by the viscosity detector 13 is less than the set value, the electric telescopic rod 12 is controlled to extend by the controller, and the distance between the first deflector 10 and the second deflector 11 decreases, which can increase the shear rate when the melt passes through and reduce the formation of eddy currents, so as to keep the pressure in the inner cavity of the die shell 301 stable and improve the product quality.

[0048] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended embodiments and their equivalents.

Claims

1. A sanitary napkin PIR film extrusion molding device based on recycled plastic particles, comprising a screw extruder (1) and a feed barrel (101) installed on the top feed port of the screw extruder (1), characterized in that: On one side of the screw extruder (1), a performance enhancement mechanism (2) is connected through an extrusion pipe (102). The performance enhancement mechanism (2) includes a barrel. A first material leveling plate (201) is fixed inside the barrel. A number of first discharge holes are formed on the plate body of the first material leveling plate (201). A number of first discharge pipes (202) communicating with the first discharge holes are fixed at the bottom end of the first material leveling plate (201). A first material valve (203) is connected to the pipe body of the first discharge pipe (202). A number of injection pipes (5) are fixedly connected to the top of the barrel. The injection pipes (5) are connected to a critical carbon dioxide generator. The critical carbon dioxide prepared by the critical carbon dioxide generator is injected into the reaction cavity formed by the first material leveling plate (201) and the barrel through the injection pipes (5). A circulation pipe (208) is fixedly connected to the bottom of the barrel. A film extrusion die head (3) is connected to one side of the circulation pipe (208). The sanitary napkin PIR film is extruded through the film extrusion die head (3). The film extrusion die head (3) includes a die shell (301). A top pressure sensor (7) is fixed to the inner wall of the top of the die shell (301). Side pressure sensors (8) are fixed to at least one inner wall of the die shell (301). At the top and bottom of the film outlet side of the die shell (301), a top lip plate (14) and a bottom lip plate are respectively arranged. An outlet gap (16) with a triangular cross-section is formed between the top lip plate (14) and the bottom lip plate. An activity groove is formed at the top of the die shell (301). A vertical extension block (141) is integrally formed at the top of the top lip plate (14). The vertical extension block (141) is adapted to the activity groove. A damping block (17) with a triangular cross-section is arranged inside the die shell (301). A driving mechanism (18) is arranged between the damping block (17) and the vertical extension block (141).

2. The sanitary napkin PIR film extrusion molding device based on recycled plastic particles according to claim 1, characterized in that: A cavity is formed on the outer side of the barrel. A heating wire (4) is arranged inside the cavity. The inner cavity of the barrel is heated through the heating wire (4).

3. The sanitary napkin PIR film extrusion molding device based on recycled plastic particles according to claim 1, characterized in that: A second material leveling plate is also fixed inside the barrel. A number of second discharge holes are formed on the second material leveling plate. A number of second discharge pipes communicating with the second discharge holes are fixed at the bottom end of the second material leveling plate. A second material valve is connected to the pipe body of the second discharge pipe. A gas precipitation cavity (204) is formed between the first material leveling plate (201) and the second material leveling plate. A U-shaped air pipe (601) communicating with the gas precipitation cavity (204) is fixed to the outer side of the barrel. An air extraction pipe (602) and a connecting pipe are fixedly connected to the side of the U-shaped air pipe (601). Solenoid valves (603) are connected to the pipe bodies of the air extraction pipe (602) and the connecting pipe. One side of the air extraction pipe (602) is connected to an air extraction pump.

4. A sanitary napkin PIR film extrusion molding device based on recycled plastic particles according to claim 1, characterized in that: A vertical cylinder (205) is formed at the bottom of the barrel. A rotating shaft (206) is movably connected to the top of the vertical cylinder (205). A first motor (207) is fixed to the bottom end of the vertical cylinder (205). The output end of the first motor (207) is fixed to the end of the rotating shaft (206). A spiral blade is fixed to the shaft body of the rotating shaft (206). The circulation pipe (208) is fixedly connected to the bottom of the vertical cylinder (205).

5. The extruding and molding equipment for sanitary napkin PIR film based on recycled plastic particles according to claim 1, wherein: A first flow guide plate (10) and a second flow guide plate (11) are arranged inside the formwork shell (301). A plurality of first flow guide holes (1001) and second flow guide holes (1101) are respectively formed in the plates of the first flow guide plate (10) and the second flow guide plate (11), and the first flow guide holes (1001) and the second flow guide holes (1101) are staggered.

6. The extruding and forming device for sanitary napkin PIR film based on recycled plastic particles according to claim 5, characterized in that: A trapezoidal cavity is formed between the first flow guide plate (10) and the formwork shell (301).

7. An extruding and molding device for sanitary napkin PIR film based on recycled plastic particles according to claim 6, characterized in that: An arc-shaped buffer block (9) is arranged in the trapezoidal cavity, and the arc-shaped buffer block (9) is located on one side of the flow pipe (208); A plurality of through grooves are formed at the bottom of the formwork shell (301). A plurality of T-shaped plates (901) are fixed at the bottom end of the arc-shaped buffer block (9), and the T-shaped plates (901) are adapted to the through grooves. Springs (902) are fixed between the side walls of the through grooves and the T-shaped plates (901).

8. An extrusion molding device for sanitary napkin PIR film based on recycled plastic particles according to claim 5, characterized in that: Extension plates are formed on both sides of the first flow guide plate (10). Sliding grooves are formed on both sides of the formwork shell (301), and the extension plates are adapted to the sliding grooves. Electric telescopic rods (12) are fixed on both sides of the formwork shell (301). The telescopic ends of the electric telescopic rods (12) extend into the sliding grooves, and the ends thereof are fixed to the extension plates. When the electric telescopic rods (12) expand and contract, the first flow guide plate (10) is driven to move, so as to adjust the distance between the first flow guide plate (10) and the second flow guide plate (11); A viscosity detector (13) is fixed on the side of the formwork shell (301), and the viscosity of the molten recycled plastic in the trapezoidal cavity is detected by the viscosity detector (13).

9. An extruding and forming device for sanitary napkin PIR film based on recycled plastic particles according to claim 5, characterized in that: The driving mechanism (18) includes a driving box, a guide rod (171) that is movably inserted into the damping block (17), and a lead screw (181) that is movably screwed to the damping block (17). First support frames (172) are movably connected to the rod bodies of the guide rod (171) and the lead screw (181); A first movable rod (182) and a screw rod (187) are movably connected to the top of the formwork shell (301). The screw rod (187) is movably screwed to the vertical extension block (141). A first gear pair (183) is arranged between the lead screw (181) and the first movable rod (182). A plurality of second support frames (19) distributed horizontally are fixed to the top end of the formwork shell (301). A second movable rod (185), a middle roller (184), and a third movable rod are respectively movably connected to the second support frames (19). The middle roller (184) is located between the second movable rod (185) and the third movable rod; A third gear pair (188) is arranged between the second movable rod (185) and the screw rod (187), and a second gear pair (186) is arranged between the third movable rod and the first movable rod (182); Guide blocks are fixed on the rod bodies between the middle roller (184) and the second movable rod (185) and on the rod bodies between the middle roller (184) and the third movable rod. Ring-shaped sleeve blocks (189) are movably inserted into the rod bodies between the middle roller (184) and the second movable rod (185) and on the rod bodies between the middle roller (184) and the third movable rod. A plurality of guide grooves adapted to the guide blocks are formed inside the ring-shaped sleeve blocks (189); A groove is formed on the outer side of the annular sleeve block (189), and a fork (1810) is movably inserted into the groove. A vertical plate is fixed to the top end of the die shell (301), and a double-headed electric telescopic rod (1811) is fixed to the top of the vertical plate. The two telescopic rods of the double-headed electric telescopic rod (1811) are respectively fixed to the two forks (1810). A worm gear (1812) is fixed to the shaft body of the middle roller (184). A worm (1813) is movably connected to the drive box. The worm (1813) meshes with the worm gear (1812). A second motor is fixed to the outside of the drive box, and the output end of the second motor is fixed to the end of the worm (1813).

10. The extruding and molding device for the sanitary napkin PIR film based on recycled plastic particles according to claim 1, characterized in that: A distance measuring sensor (15) is fixed to the outer side of the top lip plate (14), and a receiver is fixed to the outer side of the bottom lip plate. The width of the discharge gap (16) is detected by the distance measuring sensor (15) and the receiver.

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