A sanitary napkin PIR film extrusion molding equipment based on recycled plastic particles

Abstract

The present invention discloses a PIR film extrusion molding device for sanitary napkins based on recycled plastic particles, relating to the field of film extrusion molding technology. The device comprises a screw extruder and a feed barrel mounted on a feed port at the top of the screw extruder. A performance gain mechanism is connected to one side of the screw extruder via an extrusion tube. The performance gain mechanism comprises a barrel body, a first sparging plate fixed within the barrel body, and a plurality of first discharge holes formed on the plate body of the first sparging plate. The present invention is provided with a performance gain mechanism. Critical carbon dioxide produced by a critical carbon dioxide generator is injected into a reaction chamber formed by the first sparging plate and the barrel body via an injection tube, thereby contacting the molten recycled plastic. The swelling effect of the supercritical carbon dioxide reduces the entanglement concentration of the polymer molecular chains. Simultaneously, the dissolved gas increases the free volume, thereby enhancing the mobility of the molecular chains and reducing viscosity, thereby reducing extrusion pressure, reducing equipment energy consumption, and improving product quality.

Description

Technical Field

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

[0002] Recycled plastic particles mainly come from non-polluting scraps, waste or unqualified products in the industrial production process. They are made through recycling, sorting, cleaning, disinfection, crushing, granulation and other processes. Making recycled plastic particles into sanitary napkin breathable and leak-proof film (PIR) has the advantages of reducing plastic pollution and resource consumption, lowering sanitary napkin production costs and improving product competitiveness.

[0003] A Chinese invention patent, application publication number: CN115972531A, discloses an extruder for a polylactic acid breathable film production line. The extruder places a silo into a drying and crystallization device for drying and crystallization, then mixes the raw materials through a mixing device. After mixing, the raw materials are poured into a barrel from the inside of the feed port. After entering the barrel, the product is transported to the inside of the die head by a screw for molding, and then passes through a molding device, a shaping device, a corona device, a detection device, and finally a winding device for winding.

[0004] Chinese invention patent, application publication number: CN118528522A discloses a screw extruder for breathable film production, which relates to the field of plastic molding technology. A segmented reflux action is formed by a stop block and a hard spiral blade, a reflux hard pipe and a micro one-way valve to improve the heating effect, and cooperate with the heating element inside the extrusion barrel to perform preheating action; by adjusting the pitch of the hard spiral blade, the distance can be gradually adjusted at equal lengths to adapt to different raw material processing conditions and adjust to the optimal spiral extrusion pitch.

[0005] The existing technology and the existing recycled plastic granule sanitary napkin PIR film extrusion molding equipment still have at least the following defects in practical application:

[0006] First, the melt viscosity of recycled plastics is high and the flow is poor due to the breakage of molecular chains and unstable rheological properties, which requires higher extrusion pressure and increases the energy consumption of equipment. In addition, the shrinkage rate of the product is uneven and the dimensional deviation increases, making it difficult to meet the requirements of precision processing.

[0007] Secondly, the molecular weight distribution of recycled plastics is wide, resulting in high shear rate sensitivity and unstable melt viscosity. During film extrusion molding, the melt pressure in the film cavity is unevenly distributed, resulting in uneven thickness of the sanitary napkin PIR film produced. Summary of the Invention

[0008] The object 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 technology.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a PIR film extrusion molding device for sanitary napkins based on recycled plastic particles, comprising a screw extruder and a feed barrel mounted on a feed port at the top of the screw extruder, wherein one side of the screw extruder is connected to a performance gain mechanism via an extrusion tube, the performance gain mechanism comprising a barrel body, a first material refining plate fixed to the barrel body, a plurality of first discharge holes being formed on the plate body of the first material refining plate, a plurality of first discharge pipes connected to the first discharge holes being fixed to the bottom end of the first material refining plate, and a first material valve being connected to the pipe body of the first discharge pipe;

[0010] The top of the barrel is fixedly connected with a plurality of injection pipes, which are connected to the critical carbon dioxide generator. The critical carbon dioxide produced by the critical carbon dioxide generator is injected into the reaction chamber formed by the first sparging plate and the barrel through the injection pipes.

[0011] The bottom of the barrel is fixedly connected with a flow pipe, one side of which is connected to a film extrusion die head, through which the sanitary napkin PIR film is extruded;

[0012] The film extrusion die head includes a mold shell, a top pressure sensor is fixed to the inner wall of the top of the mold shell, and a side pressure sensor is fixed to the inner wall of at least one side of the mold shell;

[0013] The top and bottom of the film discharge side of the mold shell are respectively provided with a top lip plate and a bottom lip plate, and a discharge gap with a triangular cross-section is formed between the top lip plate and the bottom lip plate. A movable groove is opened on the top of the mold shell, and a vertical extension block is integrally formed on the top of the top lip plate. The vertical extension block is adapted to the movable groove. A damping block with a triangular cross-section is provided in the mold shell, and a driving mechanism is provided between the damping block and the vertical extension block.

[0014] Furthermore, a cavity is provided on the outer side of the barrel body, and a heating wire is provided in the cavity, so that the inner cavity of the barrel body is heated by the heating wire.

[0015] Furthermore, a second material leveling plate is fixed in the barrel body, and a plurality of second material discharge holes are opened on the second material leveling plate. A plurality of second material discharge pipes connected to the second material discharge holes are fixed at the bottom end of the second material leveling plate, and a second material valve is connected to the pipe body of the second material discharge pipe;

[0016] A gas separation cavity is formed between the first sparging plate and the second sparging plate;

[0017] A U-shaped air pipe connected to the gas precipitation chamber is fixed on the outside of the barrel body. An exhaust pipe and a connecting pipe are fixed on the side of the U-shaped air pipe. Solenoid valves are connected to the pipe bodies of the exhaust pipe and the connecting pipe. One side of the exhaust pipe is connected to the exhaust pump.

[0018] 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 to 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, and the flow pipe is fixedly connected to the bottom of the vertical cylinder.

[0019] Furthermore, a first guide plate and a second guide plate are provided in the mold shell, and a plurality of first guide holes and a second guide hole are respectively opened on the plate bodies of the first guide plate and the second guide plate, and the first guide holes and the second guide holes are staggered.

[0020] Furthermore, a trapezoidal cavity is formed between the first guide plate and the mold shell.

[0021] Furthermore, an arc-shaped buffer block is provided in the trapezoidal cavity, and the arc-shaped buffer block is located on one side of the flow tube;

[0022] A plurality of through slots are opened at the bottom of the mold shell, and a plurality of T-shaped plates are fixed to the bottom end of the arc-shaped buffer block. The T-shaped plates are adapted to the through slots, and a spring is fixed between the side wall of the through slot and the T-shaped plates.

[0023] Furthermore, extension plates are formed on both sides of the first guide plate, and slide grooves are formed on both sides of the formwork, the extension plates are adapted to the slide grooves, and electric telescopic rods are fixed on both sides of the formwork, the telescopic ends of the electric telescopic rods extend into the slide grooves, and the ends of the electric telescopic rods are fixed to the extension plates. When the electric telescopic rods are extended or retracted, the first guide plate is driven to move, thereby adjusting the distance between the first guide plate and the second guide plate;

[0024] A viscosity detector is fixed on the side of the mold shell, and the viscosity of the molten recycled plastic in the trapezoidal cavity is detected by the viscosity detector.

[0025] Furthermore, the driving mechanism includes a driving box, a guide rod movably connected to the damping block, and a screw rod movably screwed to the damping block, and the guide rod and the screw rod are both movably connected to the first support frame;

[0026] The top of the mold shell is movably connected with a first movable rod and a screw rod, the screw rod is movably screwed to the vertical extension block, a first gear pair is provided between the screw rod and the first movable rod, and a plurality of second support frames distributed laterally are fixed to the top of the mold shell, and the second support frames are movably connected with the second movable rod, the middle roller and the third movable rod respectively, and the middle roller is located between the second movable rod and the third movable rod;

[0027] A third gear pair is provided between the second movable rod and the screw rod, and a second gear pair is provided between the third movable rod and the first movable rod;

[0028] A guide block is fixed on the rod body between the middle roller and the second movable rod and on the rod body between the middle roller and the third movable rod. An annular sleeve block is movably inserted on the rod body between the middle roller and the second movable rod and on the rod body between the middle roller and the third movable rod. A plurality of guide grooves adapted to the guide block are opened on the inner side of the annular sleeve block.

[0029] A groove is provided on the outside of the annular sleeve, a shift fork is movably inserted in the groove, a vertical plate is fixed on the top of the mold shell, a double-headed electric telescopic rod is fixed on the top of the vertical plate, and the two telescopic rods of the double-headed electric telescopic rod are respectively fixed to the two shift forks;

[0030] A worm wheel is fixed on the shaft of the middle roller, a worm is movably connected to the drive box, the worm is engaged with the worm wheel, 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.

[0031] Furthermore, a distance measuring sensor is fixed on the outer side of the top lip plate, and a receiver is fixed on the outer side of the bottom lip plate, and the width of the discharge gap is detected by the distance measuring sensor and the receiver.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles is provided with a performance gain mechanism. The critical carbon dioxide prepared by the critical carbon dioxide preparation device is injected into the reaction chamber formed by the first material leveling plate and the barrel through an injection pipe, thereby coming into contact with the molten recycled plastic. The swelling effect of the supercritical carbon dioxide reduces the entanglement concentration of the polymer molecular chains. At the same time, the dissolved gas increases the free volume, thereby enhancing the mobility of the molecular chains, reducing the viscosity, reducing the extrusion pressure, reducing the energy consumption of the equipment, and improving the product quality.

[0034] 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 downward by the driving mechanism to reduce the discharge gap to compensate for the increase in the discharge gap under high pressure, thereby ensuring 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 by the driving mechanism to shrink toward the center of the discharge gap, 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 product quality of the sanitary napkin PIR film due to uneven thickness.

[0035] In addition, a second material distribution plate, an exhaust pipe and a connecting pipe are provided. When the air pump is started, the air pressure in the gas precipitation chamber is reduced, which promotes the precipitation of bubbles in the solution. Finally, the precipitated gas is extracted from the gas precipitation chamber through the exhaust pipe, thereby effectively reducing the amount of bubbles in the solution and improving product quality.

[0036] At the same time, a vertical cylinder, a rotating shaft and spiral blades are formed at the bottom of the barrel body. The melt enters the bottom of the barrel body along the second discharge pipe. The controller controls the first motor to start. Driven by the spiral blades, the melt enters the circulation pipe at a certain speed and pressure, thereby increasing production efficiency.

[0037] In addition, the provision of a first guide plate, a second guide plate and a trapezoidal cavity can make the melt flow more smoothly, reduce fluid resistance, help to increase extrusion speed and reduce energy consumption. Secondly, the provision of the trapezoidal cavity can prevent the pressure in the middle of the mold shell from being greater than the pressure on both sides, thereby improving product quality. Furthermore, the staggered distribution between the first guide hole and the second guide hole can enable the melt to enter the cavity formed by the first guide plate and the second guide plate at a certain pressure, further reducing the pressure fluctuation of the melt in the mold shell.

[0038] In addition, an arc-shaped buffer block is provided in the trapezoidal cavity, which can promote the melt to flow along both sides of the trapezoidal cavity, so that the melt enters the trapezoidal cavity evenly. In addition, the spring can buffer the melt flowing out of the flow tube to prevent the melt from causing excessive pressure fluctuations in the trapezoidal cavity due to excessive pressure fluctuations, thereby improving product quality.

[0039] Furthermore, a viscosity detector and a movable first guide plate are provided, and the distance between the first guide plate and the second guide plate is adjusted according to the viscosity of the melt, thereby reducing the shear stress in the flow channel, avoiding local excessive pressure causing the melt to rupture or carbonize, and increasing the shear rate when the melt passes through, reducing vortex formation, so that the pressure in the mold cavity remains stable and the product quality is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a left side axial view of the present invention;

[0041] Figure 2 It is a right rear axial view of the present invention;

[0042] Figure 3 A half-section view of the present invention;

[0043] Figure 4 An axial view of a film extrusion die of the present invention;

[0044] Figure 5 A bottom view of the film extrusion die of the present invention;

[0045] Figure 6is a first cross-sectional view of the film extrusion die of the present invention;

[0046] Figure 7 is a second cross-sectional view of the film extrusion die of the present invention;

[0047] Figure 8 Detailed view of the driving mechanism of the present invention.

[0048] In the figure: 1. Screw extruder; 101. Feed barrel; 102. Extrusion pipe; 2. Performance gain mechanism; 201. First material 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. Film extrusion die; 301. Mould 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-plate; 902. Spring; 10. First guide plate; 1001. First guide hole; 11. Second guide Flow plate; 1101, second guide hole; 12, electric telescopic rod; 13, viscosity detector; 14, top lip plate; 141, vertical extension block; 15, distance sensor; 16, discharge gap; 17, damping block; 171, guide rod; 172, first support frame; 18, driving mechanism; 181, 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, annular sleeve block; 1810, shift fork; 1811, double-headed electric telescopic rod; 1812, worm gear; 1813, worm; 19, second support frame. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] Recycled plastic particles mainly come from non-polluting scraps, waste or unqualified products in the industrial production process. They are made through recycling, sorting, cleaning, disinfection, crushing, granulation and other processes. Making recycled plastic particles into sanitary napkin breathable and leak-proof film (PIR) has the advantages of reducing plastic pollution and resource consumption, lowering sanitary napkin production costs and improving product competitiveness.

[0051] Example 1: Figure 1-Figure 4 and Figure 6-Figure 8As shown, the present invention provides a technical solution: a sanitary napkin PIR film extrusion molding device based on recycled plastic particles, comprising a controller, a screw extruder 1 and a feed barrel 101 installed on the top feed port of the screw extruder 1, the feed barrel 101 contains molten recycled plastic, the screw extruder 1 transports the molten recycled plastic, and a performance gain mechanism 2 is connected to one side of the screw extruder 1 through an extrusion tube 102, wherein, as Figure 1-Figure 3 As shown, the performance gain mechanism 2 includes a barrel body, in which a first material distribution plate 201 is fixed, a plurality of first material discharge holes in a ring array are provided on the plate body of the first material distribution plate 201, a plurality of first material discharge pipes 202 connected to the first material discharge holes are fixed at the bottom end of the first material distribution plate 201, and a first material valve 203 is connected to the pipe body of the first material discharge pipe 202. In order to prevent the molten recycled plastic from solidifying due to the temperature drop during extrusion, a cavity is provided on the outside of the barrel body, and a heating wire 4 is provided in the cavity to heat the inner cavity of the barrel body by the heating wire 4.

[0052] A plurality of injection pipes 5 are fixedly connected to the top of the barrel body, and the injection pipes 5 are connected to the critical carbon dioxide preparation device. The critical carbon dioxide prepared by the critical carbon dioxide preparation device is injected into the reaction chamber formed by the first sparging 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, and a film extrusion die 3 is connected to one side of the circulation pipe 208. The sanitary napkin PIR film is extruded through the film extrusion die 3.

[0053] like Figure 3-Figure 4 、 Figure 6-Figure 8 As shown, the film extrusion die 3 includes a mold shell 301, a top pressure sensor 7 is fixed on the top inner wall of the mold shell 301, and a side pressure sensor 8 is fixed on the inner wall of at least one side of the mold shell 301. In this embodiment, the side pressure sensor 8 is set as one, and the top pressure sensor 7 and the side pressure sensor 8 can be piezoelectric ceramic sensors, such as Figure 3 As shown, the top pressure sensor 7 and the side pressure sensor 8 are arranged longitudinally along the mold shell 301, and 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 detected by the top pressure sensor 7 and the side pressure sensor 8 respectively.

[0054] like Figure 7As shown, the top and bottom of the film discharge side of the mold shell 301 are respectively provided with a top lip plate 14 and a bottom lip plate, and a discharge gap 16 with a triangular cross-section is formed between the top lip plate 14 and the bottom lip plate. The discharge gap 16 gradually shrinks along the film discharge port of the mold shell 301, and a movable groove is opened at the top of the mold shell 301. A vertical extension block 141 is integrally formed on the top of the top lip plate 14, and the vertical extension block 141 is adapted to the movable groove. A damping block 17 with a triangular cross-section is provided in the mold shell 301, and the shrinking direction of the damping block 17 is opposite to the shrinking direction of the discharge gap 16. A driving mechanism 18 is provided between the damping block 17 and the vertical extension block 141, and the vertical extension block 141 and the damping block 17 are driven to move by the driving mechanism 18, thereby realizing the adjustment of the width of the discharge gap 16 and the pressure of the molten recycled plastic on both sides of the discharge gap 16.

[0055] like Figure 7 and Figure 8 As shown, the driving mechanism 18 includes a driving box, a guide rod 171 movably plugged into the damping block 17, and a screw rod 181 movably screwed to the damping block 17. The rod bodies of the guide rod 171 and the screw rod 181 are movably connected with a first support frame 172. The bottom end of the first support frame 172 is fixed to the bottom inner wall of the mold shell 301. The top of the mold shell 301 is movably connected with a first movable rod 182 and a screw rod 187. 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, thereby adjusting the width of the discharge gap 16. The screw rod 181 and the first movable rod 18 2, a first gear pair 183 is provided between, and a plurality of second support frames 19 distributed laterally are fixed to the top of the mold shell 301. In this scheme, the number of second support frames 19 is set to three, and the three second support frames 19 are respectively movably connected with a second movable rod 185, a middle roller 184 and a third movable rod. The middle roller 184 is located between the second movable rod 185 and the third movable rod, and a third gear pair 188 is provided between the second movable rod 185 and the screw 187. A second gear pair 186 is provided between the third movable rod and the first movable rod 182. The gear pairs in this scheme are all bevel gear pairs, and their gear ratios are not limited in this scheme.

[0056] Guide blocks are fixed on the rod body between the middle roller 184 and the second movable rod 185 and on the rod body between the middle roller 184 and the third movable rod. An annular sleeve 189 is movably inserted on the rod body between the middle roller 184 and the second movable rod 185 and on the rod body between the middle roller 184 and the third movable rod, and a plurality of guide grooves adapted to the guide blocks are provided on the inner side of the annular sleeve 189. A groove is provided on the outer side of the annular sleeve 189, and a shift fork 1810 is movably inserted in the groove. A vertical plate is fixed on the top of the mold shell 301, and a double-headed electric telescopic rod 1811 is fixed on the top of the vertical plate, and the two telescopic rods of the double-headed electric telescopic rod 1811 are respectively connected to the two shift forks 181. 0 is fixed, a worm gear 1812 is fixed on the shaft of the middle roller 184, a worm 1813 is movably connected to the drive box, the other end of the worm 1813 is movably connected to the vertical plate, the worm 1813 is meshed with the worm wheel 1812, and 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 1813. It can be known that in this scheme, a transmission method of meshing the worm 1813 and the worm wheel 1812 is adopted. The reason is that the meshing of the worm 1813 and the worm wheel 1812 can realize the self-locking property of the worm 1813, thereby preventing the second movable rod 185 or the third movable rod from rotating disorderly, and further preventing the top lip plate 14 and the damping block 17 from being misadjusted.

[0057] Specifically, the molten recycled plastic enters the barrel through the feed barrel 101, the screw extruder 1, and the extrusion tube 102. The critical carbon dioxide produced by the critical carbon dioxide generator is injected into the reaction chamber formed by the first sparging plate 201 and the barrel through the injection tube 5, thereby coming into contact with the molten recycled plastic. The swelling effect of the supercritical carbon dioxide reduces the entanglement concentration of the polymer molecular chains. At the same time, the dissolved gas increases the free volume, thereby enhancing the mobility of the molecular chains and reducing the viscosity.

[0058] 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 circulation 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 detected by the top pressure sensor 7 and the side pressure sensor 8 respectively. The detection cycle 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 middle roller 184 and the double-headed electric telescopic rod 1811 on one side of the third movable rod to retract. , the double-headed electric telescopic rod 1811 on the other side is extended, thereby driving the annular block 189 to move to the side of the middle roller 184 through the fork 1810 and driving the other annular block 189 to move to between the middle roller 184 and the second movable rod 185 through the fork 1810. 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, ensuring that the thickness of the sanitary napkin PIR film remains unchanged;

[0059] 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 middle roller 184 and the double-headed electric telescopic rod 1811 on one side of the third movable rod to extend, and the double-headed electric telescopic rod 1811 on the other side to contract, thereby driving the annular sleeve 189 to move to one side of the middle roller 184 through the fork 1810 and driving another annular sleeve 189 to move between the middle roller 184 and the third movable rod through the fork 1810. The controller controls the second motor to start, thereby driving the screw 181 to rotate through the second gear pair 186 and the first gear pair 183, and the damping block 17 contracts toward the center of the discharge gap 16, increasing the flow channel resistance in the center of the discharge gap 16, forcing the melt to diffuse to both sides, compensating for the uneven distribution of the melt pressure, and avoiding the sanitary napkin PIR film from reducing product quality due to uneven thickness.

[0060] It should be noted that, by establishing an adjustment priority through existing technology, when the pressure detected by the top pressure sensor 7 is greater than the threshold 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, the width of the discharge gap 16 is adjusted first, and then the position of the damping block 17 is adjusted. In addition, in order to facilitate the rapid adjustment of the position of the top lip plate 14, a distance sensor 15 is fixed on the outside of the top lip plate 14, and a receiver is fixed on the outside of the bottom lip plate. The width of the discharge gap 16 is detected by the distance sensor 15 and the receiver.

[0061] Example 2: Based on Example 1, Figure 3As shown, a second material leveling plate is also fixed in the barrel body, and a plurality of second discharge holes are opened on the second material leveling plate. A plurality of second discharge pipes connected with the second discharge holes are fixed to the bottom end of the second material leveling plate, and a second material valve is connected to the tube 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, and a U-shaped air pipe 601 connected with the gas precipitation chamber 204 is fixed on the outside of the barrel body, and an exhaust pipe 602 and a connecting pipe are fixedly connected to the side of the U-shaped air pipe 601, and the exhaust pipe 602 and the connecting pipe are both connected to the tube body of the exhaust pipe 602 and the connecting pipe. One side of the exhaust pipe 602 is connected to the exhaust pump.

[0062] Specifically, in order to meet production requirements, modifiers or other additives are added to the recycled plastic particles, which need to be stirred and mixed, resulting in a certain amount of bubbles in the solution. In order to prevent the presence of bubbles from affecting product quality, in this embodiment, after the critical carbon dioxide reacts with the solution, the first material valve 203 is opened, and the solution enters the gas precipitation chamber 204. The air pump is started, and the air pressure in the gas precipitation chamber 204 is reduced, which promotes the precipitation of bubbles in the solution. Finally, the precipitated gas is extracted from the gas precipitation chamber 204 through the exhaust pipe 602, thereby effectively reducing the amount of bubbles in the solution and improving product quality.

[0063] Example 3: Based on Example 1 or Example 2, Figure 3 As shown, a vertical cylinder 205 is formed at the bottom of the barrel body, and 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 on the shaft body of the rotating shaft 206. The circulation pipe 208 is fixedly connected to the bottom of the vertical cylinder 205.

[0064] 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 blades, the melt enters the circulation pipe 208 at a certain speed and pressure, thereby increasing production efficiency.

[0065] Example 4: Figure 4 、 Figure 6 and Figure 7 As 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, and a plurality of first guide holes 1001 and second guide holes 1101 are respectively opened on the plate bodies 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.

[0066] It can be understood that the setting of the trapezoidal cavity can, firstly, make the melt flow more smoothly, reduce fluid resistance, help to increase extrusion speed and reduce energy consumption; secondly, during the extrusion molding process, it can help to quickly dissipate heat and prevent the melt performance from being degraded due to local overheating; thirdly, 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, thereby improving product quality.

[0067] It is also understandable that the staggered distribution between the first guide holes 1001 and the second guide holes 1101 enables the melt to 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.

[0068] Example 5: Based on Example 4, Figure 5 and Figure 6 As shown, an arc-shaped buffer block 9 is provided in the trapezoidal cavity, and the arc-shaped buffer block 9 is located on one side of the circulation tube 208. In addition, a plurality of through grooves are opened at the bottom of the mold shell 301, and a plurality of T-shaped plates 901 are fixed to the bottom end of the arc-shaped buffer block 9, and the T-shaped plates 901 are adapted to the through grooves. A spring 902 is fixed between the side wall of the through groove and the T-shaped plate 901, and the plate body of the T-shaped plate 901 is fitted with the bottom plate body of the mold shell 301 to prevent the melt from leaking through the gap between the plate body of the T-shaped plate 901 and the bottom plate body of the mold shell 301.

[0069] The setting of the arc-shaped buffer block 9 can promote the melt to flow along both sides of the trapezoidal cavity, so that the melt enters the trapezoidal cavity evenly. In addition, the spring 902 can buffer the melt flowing out of the circulation tube to prevent the melt from causing excessive pressure fluctuations in the trapezoidal cavity due to excessive pressure fluctuations, thereby improving product quality.

[0070] Example 6: Based on Example 2 to Example 5, Figure 6 As shown, extension plates are formed on both sides of the first guide plate 10, and slide grooves are provided on both sides of the mold shell 301, and the extension plates are adapted to the slide grooves. Electric telescopic rods 12 are fixed on both sides of the mold shell 301, and the telescopic ends of the electric telescopic rods 12 extend into the slide grooves, and the ends thereof are fixed to the extension plates. When the electric telescopic rods 12 are extended or retracted, they drive the first guide plate 10 to move, thereby adjusting the distance between the first guide plate 10 and the second guide plate 11. A viscosity detector 13 is fixed on the side of the mold shell 301, and the viscosity of the molten recycled plastic in the trapezoidal cavity is detected by the viscosity detector 13.

[0071] Specifically, since recycled materials from different sources undergo different degrees of thermal degradation, the viscosity of the melt may fluctuate greatly. When the viscosity value detected by the viscosity detector 13 is greater than the set value, the controller controls the electric telescopic rod 12 to contract, and the distance between the first guide plate 10 and the second guide plate 11 increases, which can reduce the shear stress in the flow channel and avoid local pressure being too high to cause the melt to rupture or carbonize. When the viscosity value detected by the viscosity detector 13 is less than the set value, the controller controls the electric telescopic rod 12 to extend, and the distance between the first guide plate 10 and the second guide plate 11 decreases, which can increase the shear rate of the melt when passing through and reduce the formation of vortexes, thereby keeping the pressure in the inner cavity of the mold shell 301 stable and improving product quality.

[0072] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is limited by the accompanying embodiments and their equivalents.

Claims

1. A PIR film extrusion molding device for sanitary napkins based on recycled plastic particles, comprising a screw extruder (1) and a feed barrel (101) mounted on a feed port at the top of the screw extruder (1), characterized in that: One side of the screw extruder (1) is connected to a performance gain mechanism (2) via an extrusion tube (102), the performance gain mechanism (2) comprising a barrel body, a first material leveling plate (201) being fixed in the barrel body, a plurality of first discharge holes being opened on the plate body of the first material leveling plate (201), a plurality of first discharge pipes (202) being connected to the first discharge holes being fixed at the bottom end of the first material leveling plate (201), and a first material valve (203) being connected to the pipe body of the first discharge pipe (202); The top of the barrel body is fixedly connected to a plurality of injection pipes (5), the injection pipes (5) are connected to the critical carbon dioxide preparation device, and the critical carbon dioxide prepared by the critical carbon dioxide preparation device is injected into the reaction chamber formed by the first sparging plate (201) and the barrel body through the injection pipes (5); The bottom of the barrel body is fixedly connected to a circulation pipe (208), one side of the circulation pipe (208) is connected to a film extrusion die (3), and the sanitary napkin PIR film is extruded through the film extrusion die (3); The film extrusion die (3) comprises a mold shell (301), a top pressure sensor (7) is fixed to the top inner wall of the mold shell (301), and a side pressure sensor (8) is fixed to at least one side inner wall of the mold shell (301); A top lip plate (14) and a bottom lip plate are respectively provided at the top and bottom of the film discharge side of the mold shell (301), and a discharge gap (16) with a triangular cross section is formed between the top lip plate (14) and the bottom lip plate. A movable groove is provided at the top of the mold shell (301), and 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 movable groove. A damping block (17) with a triangular cross section is provided in the mold shell (301), and a driving mechanism (18) is provided between the damping block (17) and the vertical extension block (141).

2. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 1, characterized in that: A cavity is provided on the outside of the barrel body, and a heating wire (4) is provided in the cavity, and the inner cavity of the barrel body is heated by the heating wire (4).

3. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 1, characterized in that: A second material distribution plate is also fixed in the barrel body, and a plurality of second material discharge holes are opened on the second material distribution plate. A plurality of second material discharge pipes connected to the second material discharge holes are fixed at the bottom end of the second material distribution plate, and a second material valve is connected to the pipe body of the second material discharge pipe; A gas precipitation cavity (204) is formed between the first sparging plate (201) and the second sparging plate; A U-shaped air pipe (601) connected to the gas precipitation chamber (204) is fixed on the outside of the barrel body. An air extraction pipe (602) and a connecting pipe are fixedly connected to the side of the U-shaped air pipe (601). The air extraction pipe (602) and the connecting pipe are both connected to a solenoid valve (603). One side of the air extraction pipe (602) is connected to an air extraction pump.

4. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 1, characterized in that: A vertical cylinder (205) is formed at the bottom of the barrel body, and 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), and 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), and a circulation pipe (208) is fixedly connected to the bottom of the vertical cylinder (205).

5. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 1, characterized in that: A first guide plate (10) and a second guide plate (11) are provided in the mold shell (301); a plurality of first guide holes (1001) and a plurality of second guide holes (1101) are respectively provided on the plate bodies of the first guide plate (10) and the second guide plate (11); the first guide holes (1001) and the second guide holes (1101) are staggered.

6. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 5, characterized in that: A trapezoidal cavity is formed between the first guide plate (10) and the mold shell (301).

7. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 6, characterized in that: An arc-shaped buffer block (9) is provided in the trapezoidal cavity, and the arc-shaped buffer block (9) is located on one side of the flow tube (208); The bottom of the mold shell (301) is provided with a plurality of through slots. The bottom end of the arc-shaped buffer block (9) is fixed with a plurality of T-shaped plates (901). The T-shaped plates (901) are adapted to the through slots. A spring (902) is fixed between the side wall of the through slot and the T-shaped plates (901).

8. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 5, characterized in that: Extension plates are formed on both sides of the first guide plate (10), and slide grooves are formed on both sides of the mold shell (301), and the extension plates are adapted to the slide grooves. Electric telescopic rods (12) are fixed on both sides of the mold shell (301), and the telescopic ends of the electric telescopic rods (12) extend into the slide grooves, and the ends thereof are fixed to the extension plates. When the electric telescopic rods (12) are extended or retracted, the first guide plate (10) is driven to move, thereby adjusting the distance between the first guide plate (10) and the second guide plate (11); A viscosity detector (13) is fixed to the side of the mold shell (301), and the viscosity of the molten recycled plastic in the trapezoidal cavity is detected by the viscosity detector (13).

9. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 5, characterized in that: The driving mechanism (18) includes a driving box, a guide rod (171) movably connected to the damping block (17), and a screw rod (181) movably screwed to the damping block (17), and the guide rod (171) and the screw rod (181) are both movably connected to a first support frame (172); The top of the mold shell (301) is movably connected to a first movable rod (182) and a screw rod (187), the screw rod (187) is movably screwed to the vertical extension block (141), a first gear pair (183) is provided between the screw rod (181) and the first movable rod (182), and a plurality of second support frames (19) distributed laterally are fixed to the top of the mold shell (301), the second support frames (19) are movably connected to the second movable rod (185), the middle roller (184) and the third movable rod, and the middle roller (184) is located between the second movable rod (185) and the third movable rod; A third gear pair (188) is provided between the second movable rod (185) and the screw rod (187), and a second gear pair (186) is provided between the third movable rod and the first movable rod (182); A guide block is fixed on the rod body between the middle roller (184) and the second movable rod (185) and on the rod body between the middle roller (184) and the third movable rod, and an annular sleeve block (189) is movably inserted on the rod body between the middle roller (184) and the second movable rod (185) and on the rod body between the middle roller (184) and the third movable rod, and a plurality of guide grooves adapted to the guide block are opened on the inner side of the annular sleeve block (189); A groove is formed on the outer side of the annular sleeve (189), and a shift fork (1810) is movably inserted into the groove. A vertical plate is fixed to the top of the mold 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 shift forks (1810). A worm wheel (1812) is fixed on the shaft of the middle roller (184), a worm (1813) is movably connected to the drive box, the worm (1813) is meshed with the worm wheel (1812), 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 (1813).

10. The PIR film extrusion molding equipment for sanitary napkins based on recycled plastic particles according to claim 1, characterized in that: A distance 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 distance sensor (15) and the receiver.

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