Process for the preparation of a compact thermoplastic polyurethane of porous structure

Abstract

The application discloses a preparation process of compact thermoplastic polyurethane with porous structure, which comprises the following steps: firstly, starting a glue pumping pump to pump polyurethane glue into a spinneret to spray into a yarn, then injecting air into an air injection pipe, and then starting a forward-reverse motor to drive a yarn conveying frame to move with a glue yarn head end until the glue yarn head end is pushed over by a yarn turning block, and then taking the glue yarn head end to be wound on a yarn winding shaft while covering an anti-pressure film on the outside of the glue yarn to be synchronously wound. The yarn conveying device is arranged, the yarn conveying frame is used to move with the bonded glue yarn in a coagulation bath to be fully coagulated, the hand of a staff member is avoided from being inserted into the coagulation bath to contact the glue yarn to move, the yarn turning block is used to push the bottom of the yarn conveying frame to be turned upward to expose the glue yarn head end on the coagulation bath, manual pulling of the glue yarn before winding is replaced, and harm and inconvenience caused by manual pulling of the glue yarn before winding are avoided.

Description

Technical Field

[0001] This invention relates to the field of plastic preparation technology, specifically to a preparation process for a porous, dense thermoplastic polyurethane. Background Technology

[0002] Polyurethane is a highly resilient material with an elongation at break that can reach up to 800%. Therefore, polyurethane is widely used in leather, footwear, clothing, decoration, and track manufacturing. Polyurethane fibers are primarily produced using a wet spinning method with ammonium dihydrogen phosphate solution as the coagulation bath.

[0003] Because workers need to remove the ends of the polyurethane filaments from this solution for winding and storage, frequent pulling in this solution will inevitably corrode gloves and even skin, posing a safety hazard to workers. In addition, in order to form a porous structure in the polyurethane filaments so that they are permeable to water and air, the existing method involves exposing a section of the filament to air after it is spun before it falls into the coagulation bath to solidify, allowing air to enter the filament. It is conceivable that this method makes it difficult for the falling filament to fully mix in air, and thus can only form pores on its surface, failing to achieve a good water and air permeability effect. Summary of the Invention

[0004] The purpose of this invention is to provide a process for preparing a porous, dense thermoplastic polyurethane to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a process for preparing a porous, dense thermoplastic polyurethane, comprising the following steps: first, injecting dense thermoplastic polyurethane adhesive into a storage tank, simultaneously injecting coagulation bath liquid into a coagulation bath, then activating a pump at the bottom of the storage tank to pump the adhesive into a pump pipe, which then leads to the coagulation bath; and further comprising the following steps:

[0006] I. The process of forming holes by spinning adhesive:

[0007] S1. The adhesive liquid leading to the coagulation bath is squeezed into the spinneret and extruded as filaments through several spinneret holes.

[0008] S2. Next, start the air compressor to inject air into the air injection pipe, and discharge it from the air outlet on the bottom of the air distribution pipe, which then blows it into the filamentous adhesive to form air holes.

[0009] S3. The adhesive liquid that forms pores falls into the filament sleeve through the discharge trough, where it reassembles into filaments and falls into the coagulation bath liquid in the coagulation bath.

[0010] II. Fiber Pulling and Solidification Stage:

[0011] S4. After the filament falls from the polyfilament sleeve and solidifies in the coagulation bath, start the forward and reverse motor to rotate forward and drive the lead screw to rotate, thereby moving the wire feeding frame closer to the front end of the coagulation bath.

[0012] S5. The rubber filaments are moved and stretched in the coagulation bath by the drawing shaft.

[0013] III. The compressive strength stage of filament winding:

[0014] S6. Until the wire pusher block at the top of the wire feeder is pushed back by the wire rotating block, it will cause the wire drawing shaft to rotate forward and flip upward.

[0015] S7. The workers remove the solidified rubber filaments from the drawing shaft, and then wind the rubber filaments extruded from each row of several spinnerets onto the winding shafts at different positions.

[0016] S8. At the same time, the pressure-resistant membrane is also wound onto the winding spool, and the rubber filaments are embedded in the membrane groove.

[0017] As a further improvement to this technical solution, the polyurethane preparation apparatus includes a pore-forming device suspended in one end of a coagulation bath. The pore-forming device includes a spinneret sleeved to a pump hose, a pore-forming box snapped into the bottom of the spinneret, and an air injection pipe embedded in the top of the pore-forming box. The spinneret has a hollow trapezoidal structure with an open top. The bottom surface of the spinneret has several rows of spinneret holes. The air injection pipe is placed inside the pore-forming box and has several air distribution pipes connected to both sides in a horizontal radial direction. The air distribution pipes are located below the rows of spinneret holes. The bottom surface of the air distribution pipes and directly below the spinneret holes has an air outlet. The bottom surface of the pore-forming box and directly below each row of spinneret holes has a material leakage groove.

[0018] As a further improvement to this technical solution, the cross-section of the air distribution pipe is triangular with its apex facing upwards. One end of the air injection pipe is sealed and embedded in the inner wall of the perforation box, and the other end of the air injection pipe is connected to the air compressor through an air pipe. The outer end of the air distribution pipe is a closed end.

[0019] As a further improvement to this technical solution, the bottom surface of the spinneret is symmetrically provided with retaining strips at both ends, and the top surface of the perforation box is symmetrically provided with inserts that connect with the retaining strips at both ends.

[0020] As a further improvement to this technical solution, the bottom surface of the forming box and the front and rear sides of the material discharge trough are vertically welded with wire guide plates. The bottom edge of the wire guide plate facing away from the glue storage tank is rotatably connected to a wire guide roller. Several wire gathering sleeves are welded between a pair of wire guide plates on the front and rear sides of each material discharge trough. The wire gathering sleeves are located directly below the spinneret holes. The height of each pair of wire guide plates gradually decreases from the front to the rear of the forming box.

[0021] As a further improvement to this technical solution, the coagulation bath is equipped with a wire feeding device for pulling the filaments sprayed from the hole-forming device to the front end of the coagulation bath. The wire feeding device includes a wire feeding frame placed in the coagulation bath, a threaded ring for supporting the rotation and movement of the wire feeding frame, a screw for driving the threaded ring to move along its axial direction, and a wire-rotating block located near the front end of the coagulation bath for driving the bottom end of the wire feeding frame to tilt backward and upward. One end of the screw is coaxially connected to a forward and reverse motor. Several wire-drawing shafts are arranged vertically at intervals on the rear side of the bottom of the wire feeding frame. The several wire-drawing shafts are located behind the bottom of each pair of wire-drawing plates. Several wire-drawing needles are welded at equal intervals on the front side of the wire-drawing shafts.

[0022] As a further improvement to this technical solution, a sleeve is welded to one radial side of the threaded ring, and rotating columns that are inserted into the sleeve are welded to the left and right sides of the top of the wire feeder. A wire pusher block is welded to the middle of the top of the wire feeder, and a roller is rotatably connected to the bottom of the rotating block.

[0023] As a further improvement to this technical solution, a three-sided inclined rod is welded to the bottom rear of the wire feeding frame, and a wire guide shaft is embedded between the three-sided inclined rod and in front of the wire drawing shaft at a horizontal distance. Several wire splitting grooves are equally spaced on the outer side of the wire guide shaft.

[0024] As a further improvement to this technical solution, a winding device for winding filaments in a solidified state is provided at the front end of the coagulation bath. The winding device includes symmetrically arranged winding frames, rotatable winding shafts arranged vertically between the winding frames, and film winding shafts located above and below the winding frames.

[0025] As a further improvement to this technical solution, one end of the winding shaft is coaxially connected to a winding motor, and an anti-pressure membrane is wound around the outside of the winding shaft. The anti-pressure membrane has symmetrically formed membrane grooves on both sides.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. In the preparation process of this porous dense thermoplastic polyurethane, a pore-forming device is set up, and air is injected into the interior of the filament by the cooperation of the pore-forming box and the air injection pipe through the air distribution pipe. The porous structure is formed by macroscopic physical means. The filament is then restored to a filament shape by the polyfilament sleeve and falls into the coagulation bath to solidify, thus preserving its internal porous structure and achieving the effect of water permeability and air permeability, which has practical value.

[0028] 2. In the preparation process of this porous dense thermoplastic polyurethane, a feeding device is set up to use the feeding frame to move the bonded filaments in the coagulation bath for complete coagulation. This avoids the workers' hands from being put into the coagulation bath and touching the filaments. At the same time, the rotating block pushes the bottom of the feeding frame forward and upward, exposing the filament ends to the coagulation bath. This replaces the manual pulling and winding of the filaments before winding, thus avoiding the injury and inconvenience.

[0029] 3. In the preparation process of this porous dense thermoplastic polyurethane, a winding device is set up to wind several rubber filaments in batches using upper and lower winding shafts to avoid them from tangling. At the same time, the anti-compression membrane is wound together with the rubber filaments to form layers of barriers, thereby preventing the rubber filaments from directly contacting and compressing each other, which would affect the internal porous structure. In addition, the anti-compression membrane can be recycled and reused, which will not cause waste and has the value of promotion and use.

[0030] 4. In the preparation process of this porous dense thermoplastic polyurethane, the gas distribution pipe is connected to the gas injection pipe and can separate the rubber filaments discharged from the gas outlet and mix in air. A porous structure can be formed inside the rubber filaments through macroscopic physical operation. Its design is ingenious, the structure is simple and reasonable, and it has practical value. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall spinneret structure of Example 1;

[0032] Figure 2 This is a schematic diagram of the overall wire-drawing structure of Example 1;

[0033] Figure 3 This is one of the schematic diagrams of the assembly structure of the hole forming device and the wire feeding device in Example 1;

[0034] Figure 4 This is the second schematic diagram of the assembly structure of the hole-forming device and the wire feeding device in Example 1;

[0035] Figure 5 This is one of the side views of the hole-forming device and wire feeding device assembled in Example 1;

[0036] Figure 6 This is the second side view of the assembly of the hole-forming device and the wire feeding device in Example 1;

[0037] Figure 7 This is a schematic diagram of the assembly structure of the wire winding device in Example 1;

[0038] Figure 8 This is a partial exploded view of the hole-forming device in Example 1.

[0039] Figure 9 This is an exploded view of the hole-forming apparatus in Example 1;

[0040] Figure 10 This is a full sectional view of the perforation box in Example 1;

[0041] Figure 11 This is a schematic diagram of the wire feeder in the upright state of Example 1;

[0042] Figure 12 This is a schematic diagram of the wire feeder in the flipped-up state of Example 1;

[0043] Figure 13 This is a schematic diagram of the wire-rotating block structure in Example 1.

[0044] The meanings of the labels in the diagram are as follows:

[0045] 100. Glue storage tank; 110. Glue pump hose; 120. Coagulation bath;

[0046] 200. Hole-forming device; 210. Spinneret; 211. Spinneret orifice; 212. Clamping bar; 220. Hole-forming box; 221. Feed trough; 222. Wire guide plate; 223. Wire guide roller; 224. Wire gathering sleeve; 225. Insert bar; 230. Air injection pipe; 231. Air distribution pipe; 232. Air outlet;

[0047] 300. Wire feeding device; 310. Wire feeding frame; 311. Wire pusher block; 312. Three-sided diagonal bar; 313. Rotating column; 320. Threaded ring; 321. Sleeve; 330. Lead screw; 331. Forward and reverse motor; 340. Wire pulling shaft; 341. Wire pulling needle; 350. Wire guide shaft; 351. Wire separating groove; 360. Wire rotating block; 361. Roller; 362. Support frame;

[0048] 400. Winding device; 410. Winding frame; 411. Extension block; 420. Winding shaft; 421. Winding motor; 430. Film winding shaft; 440. Pressure-resistant film; 441. Film groove. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be understood that the terms "central axis," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0051] Example 1

[0052] Please see Figures 1-13 As shown, the present invention provides a process for preparing a porous, dense thermoplastic polyurethane, comprising the following steps: first, injecting dense thermoplastic polyurethane adhesive into a storage tank 100, and simultaneously injecting a coagulation bath into a coagulation bath 120; then, starting a pump at the bottom of the storage tank 100 to pump the adhesive into a pump pipe 110, which then leads to the coagulation bath 120, wherein the coagulation bath 120 is equipped with a coagulation bath containing ammonium dihydrogen phosphate solution for coagulating the polyurethane membrane; the process further comprises the following steps:

[0053] I. The process of forming holes by spinning adhesive:

[0054] S1. The adhesive liquid leading to the coagulation bath 120 is squeezed into the spinneret 210 and extruded as filaments through several spinneret holes 211.

[0055] S2. Next, start the air compressor to inject air into the air injection pipe 230 and discharge it from the air outlet 232 on the bottom surface of the air distribution pipe 231. Then, blow it into the filamentous adhesive to form air holes. Since the air distribution pipe 231 separates the adhesive filaments discharged from the air outlet 232 and mixes in the air, a porous structure can be formed inside the adhesive filaments through macroscopic physical operations.

[0056] S3. The pore-forming adhesive liquid falls into the filament sleeve 224 through the discharge trough 221 and is re-aggregated into filaments before falling into the coagulation bath liquid in the coagulation bath 120. The filament sleeve 224 effectively fuses the separated adhesive filaments back into filaments, while retaining the internal porous structure.

[0057] II. Fiber Pulling and Solidification Stage:

[0058] S4. After the filament falls from the filament sleeve 224 and solidifies in the coagulation bath, start the forward and reverse motor 331 to rotate forward and drive the lead screw 330 to rotate, thereby driving the filament feeder 310 to move closer to the front end of the coagulation bath 120, so that the filament is fully immersed in the coagulation bath.

[0059] S5. The rubber filament is moved and stretched in the coagulation bath 120 by the drawing shaft 340, which replaces the manual pulling of the rubber filament before winding, thus avoiding the damage and inconvenience.

[0060] III. The compressive strength stage of filament winding:

[0061] S6. Until the push block 311 at the top of the wire feeder 310 is pushed and flipped by the rotating block 360, the wire drawing shaft 340 is driven to rotate forward and flip upward. At this time, the wire drawing shaft 340 pulls the rubber wire out of the coagulation bath surface, and the beginning of the rubber wire can be easily picked up without contacting the coagulation bath for winding and storage.

[0062] S7. The worker removes the solidified rubber filament from the filament-drawing shaft 340, and then winds the rubber filaments extruded from each row of several spinnerets 211 onto the winding shafts 420 at different positions to avoid the rubber filaments from different rows from getting tangled. The winding shaft 420 located at the top winds the rubber filament from above, and the winding shaft 420 located at the bottom winds the rubber filament from below, so that the pressure-resistant membrane 440 covers the outside of the rubber filament for layer-by-layer protection.

[0063] S8. At the same time, the pressure-resistant membrane 440 is also wound onto the winding shaft 420, and the rubber filament is embedded in the membrane groove 441 to prevent the rubber filament from being deformed due to excessive pressure after winding, which would lead to instability of the porous structure.

[0064] In this embodiment, the polyurethane preparation apparatus includes a pore-forming device 200 suspended in one end of the coagulation bath 120. The pore-forming device 200 includes a spinneret 210 sleeved with a pump hose 110, a pore-forming box 220 snapped into the bottom of the spinneret 210, and an air injection pipe 230 embedded in the top of the pore-forming box 220. An air compressor is provided outside this end of the coagulation bath 120 and is connected to the air injection pipe 230 through an air pipe to supply air. The spinneret 210 has an internally hollow trapezoidal structure with an open top. Several rows of spinneret holes 211 are formed on the bottom surface of the spinneret 210. An air injection pipe 230 is placed inside the forming box 220, with several air distribution pipes 231 connected to both sides of a horizontal radial section. Each air distribution pipe 231 is located below one of the rows of spinneret holes 211, meaning that each spinneret hole 211 is located below a corresponding air distribution pipe 231. This is used to separate the falling adhesive liquid, allowing sufficient air to enter and macroscopically assisting in the formation of a porous structure inside. An air outlet 232 is formed on the bottom surface of the air distribution pipe 231, directly below the spinneret holes 211. A material leakage groove 221 is formed on the bottom surface of the forming box 220, directly below each row of spinneret holes 211, allowing the coagulation bath liquid to overflow to below the air injection pipe 230.

[0065] Specifically, the air distribution pipe 231 has a triangular cross-section with its apex facing upwards. The width of the base of the air distribution pipe 231 is smaller than the diameter of the spinneret orifice 211, so that the air distribution pipe 231 can smoothly cut the falling adhesive without completely separating the adhesive, ensuring that the adhesive can still adhere and form filaments. One end of the air injection pipe 230 is sealed and embedded in the inner wall of the perforation box 220, and the other end of the air injection pipe 230 is connected to the air compressor through an air pipe. The outer end of the air distribution pipe 231 is a closed end, so that the air inside the air distribution pipe 231 can only be ejected from the air outlet 232.

[0066] Furthermore, the bottom surface of the spinneret 210 is symmetrically provided with retaining strips 212 at both ends. The cross-section of the retaining strips 212 is L-shaped, thus forming a limiting structure. The top surface of the perforation box 220 is symmetrically provided with insert strips 225 that are inserted into the retaining strips 212, making the perforation box 220 easy to assemble and disassemble and stably suspended.

[0067] Furthermore, a wire guide plate 222 is vertically welded to the bottom surface of the perforation box 220 and to the front and rear sides of the material discharge trough 221. A guide roller 223 is rotatably connected below the bottom edge of the wire guide plate 222 facing away from the glue storage tank 100, so that when the glue filament is drawn out from the bottom of the wire guide plate 222 and pulled towards the front end of the coagulation bath 120, it can roll into contact with the guide roller 223, thus preventing damage and deformation of the glue filament. Several filament-gathering sleeves 224 are welded between a pair of wire guide plates 222 on the front and rear sides of each material discharge trough 221. The filament-gathering sleeves 224 are located directly below the spinneret 211 and are used to gather the air-filled glue filaments and re-aggregate them into porous filaments. The height of each pair of wire guide plates 220 gradually decreases from the front to the rear of the perforation box 220, so that the glue filaments drawn out from the bottom of a pair of wire guide plates 220 at different positions will not touch or entangle.

[0068] In addition, the coagulation bath 120 is equipped with a wire feeding device 300 for pulling the adhesive filaments sprayed from the hole forming device 200 to the front end of the coagulation bath 120. The wire feeding device 300 includes a wire feeding frame 310 placed in the coagulation bath 120, a threaded ring 320 for supporting the rotation and movement of the wire feeding frame 310, a lead screw 330 for driving the threaded ring 320 to move along its axial direction, and a wire rotating block 360 located near the front end of the coagulation bath 120 for driving the bottom end of the wire feeding frame 310 to tilt backward and upward. One end of the lead screw 330 is coaxially connected to a forward and reverse motor 331. The forward and reverse principle of the forward and reverse motor 331 is as well known to those skilled in the art. The forward and reverse motor 331 is equipped with a forward and reverse switch and is connected to it through a wire to form a forward and reverse control circuit. The forward and reverse switch has three positions, namely forward and reverse position and intermediate position. The intermediate position controls the motor to stop working, which facilitates smooth switching between forward and reverse. The forward and reverse motor 331 drives the lead screw 330 to rotate, which in turn moves the threaded ring 320 along the central axis of the lead screw 330 toward the front end of the coagulation bath 120 until the top of the wire feeder 310 is blocked by the wire rotating block 360 and flips backward. Several wire pulling shafts 340 are arranged vertically at intervals on the rear side of the bottom of the wire feeder 310. These shafts are located behind the bottom of each pair of wire guide plates 220, allowing the wire pulling shafts 340 to move forward and pull the rubber filaments emerging from the bottom of the wire guide plates 220. Several wire pulling needles 341 are welded at equal intervals on the front side of the wire pulling shafts 340. Adjacent wire pulling needles 341 clamp the rubber filaments to stabilize their movement. When the top of the wire feeder 310 flips backward, the wire pulling shafts 340 flip forward and upward to expose the surface of the coagulation bath, allowing workers to easily and safely retrieve them.

[0069] Specifically, a sleeve 321 is welded to one radial side of the threaded ring 320, and rotating columns 313 that insert into the sleeve 321 are welded to the left and right sides of the top of the wire feeder 310. A wire pusher block 311 is welded to the middle of the top of the wire feeder 310. The wire pusher block 311 has an arc structure to facilitate smooth sliding with the rotating wire block 360. The greater the thickness of the wire pusher block 311, the greater the backward tilt angle, so that the wire drawing shaft 340 is closer to the surface of the coagulation bath, bringing out the end of the rubber wire for easy removal. A roller 361 is rotatably connected to the bottom of the rotating wire block 360 to reduce friction when in contact with the wire pusher block 311, allowing it to slide smoothly and overturn the pusher block. Supports 362 extending diagonally downward to the sides of the coagulation bath 120 are welded to the left and right sides of the top of the rotating wire block 360. The ends of the supports 362 are fixedly connected to the coagulation bath 120 by bolts, making the rotating wire block 360 stable.

[0070] Furthermore, a three-sided diagonal bar 312 is welded to the rear bottom of the wire feeder 310. A guide shaft 350 is embedded between the three diagonal bars 312 and in front of the wire drawing shaft 340. When the bottom end of the wire feeder 310 is flipped up, the guide shaft 350 is positioned above the coagulation bath, allowing the filament to be pulled around the upper surface of the guide shaft 350, thus enabling smooth stretching without damage. Several filament-separating grooves 351 are evenly spaced on the outer side of the guide shaft 350 to embed the filaments, allowing them to be pulled separately and avoiding tangling, thus preparing for subsequent winding and storage.

[0071] In addition, a winding device 400 for winding solidified filaments is provided at the front end of the coagulation bath 120. The winding device 400 includes symmetrically arranged winding frames 410, rotatable winding shafts 420 arranged vertically between the winding frames 410, and film winding shafts 430 located above and below the winding frames 410. The bottom of the winding frames 410 is fixed to the ground with bolts. Extension blocks 411 are welded to the upper and lower ends of the winding frames 410 and to the side facing the coagulation bath 120. The film winding shafts 430 are inserted into the extension blocks 411 and rotate.

[0072] Specifically, a winding motor 421 is coaxially connected to one end of the winding spool 420, and an anti-pressure membrane 440 is wound around the outside of the winding spool 430. The anti-pressure membrane 440 is made of plastic and is in the form of a film sheet. The two sides of the anti-pressure membrane 440 are symmetrically provided with membrane grooves 441 for embedding the rubber filaments, so that the rubber filaments wound layer by layer are blocked by the anti-pressure membrane 440, thereby avoiding direct contact and compression deformation between the rubber filaments, which would affect the internal porous structure. In addition, the anti-pressure membrane 440 can be recycled and reused, so as not to cause waste.

[0073] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing a porous, dense thermoplastic polyurethane, comprising the following steps: First, dense thermoplastic polyurethane adhesive is injected into a storage tank (100), and simultaneously, coagulation bath liquid is injected into a coagulation bath (120). Then, the adhesive pump at the bottom of the storage tank (100) is started to pump the adhesive into the pump pipe (110), which then leads to the coagulation bath (120). The method is characterized by further including the following steps: I. The process of forming holes by spinning adhesive: S1. The adhesive liquid leading to the coagulation bath (120) is squeezed into the spinneret (210) and extruded as filaments through several spinneret holes (211); S2. Next, start the air compressor to inject air into the air injection pipe (230) and discharge it from the air outlet (232) on the bottom surface of the air distribution pipe (231), and then blow it into the filamentous adhesive to form air holes. S3. The adhesive liquid that forms pores falls through the discharge trough (221) into the filament sleeve (224), where it gathers into filaments again and falls into the coagulation bath liquid in the coagulation bath (120). II. Fiber Pulling and Solidification Stage: S4. After the filament falls from the polyfilament sleeve (224) and solidifies in the coagulation bath, start the forward and reverse motor (331) to rotate forward and drive the lead screw (330) to rotate, thereby driving the wire feeder (310) to move closer to the front end of the coagulation bath (120). S5, the filaments are moved and stretched in the coagulation bath (120) by the pulling shaft (340) and solidify; III. The compressive resistance stage of the filament winding: S6. Until the push block (311) at the top of the wire feeder (310) is pushed back by the wire rotating block (360), it drives the wire drawing shaft (340) to rotate forward and flip upward. S7. The staff removes the solidified rubber filament from the wire drawing shaft (340) and then winds the rubber filament extruded from each row of several spinnerets (211) onto the winding shafts (420) at different positions. S8. At the same time, the pressure-resistant membrane (440) is also wound onto the winding spool (420), and the adhesive filaments are embedded in the membrane groove (441); The coagulation bath (120) is equipped with a wire feeding device (300) for pulling the rubber filament sprayed from the hole-forming device (200) to the front end of the coagulation bath (120). The wire feeding device (300) includes a wire feeding frame (310) placed in the coagulation bath (120), a threaded ring (320) for supporting the rotation and movement of the wire feeding frame (310), a lead screw (330) for driving the threaded ring (320) to move along its axial direction, and a wire feeding device (330) near the front end of the coagulation bath (120). A rotating wire block (360) is provided at the end to drive the bottom end of the wire feeder (310) to tilt backward and upward. One end of the wire rod (330) is coaxially connected to a forward and reverse motor (331). Several wire pulling shafts (340) are arranged vertically at intervals on the rear side of the bottom of the wire feeder (310). The several wire pulling shafts (340) are located behind the bottom of each pair of wire guide plates (222). Several wire pulling needles (341) are welded at equal intervals on the front side of the wire pulling shafts (340). The front end of the coagulation bath (120) is provided with a filament winding device (400) for winding filaments in a coagulated state. The filament winding device (400) includes filament winding frames (410) arranged symmetrically, rotatable filament winding shafts (420) arranged vertically between the filament winding frames (410), and film winding shafts (430) arranged above and below the filament winding frames (410). One end of the filament winding shaft (420) is coaxially connected to a filament winding motor (421). An anti-pressure membrane (440) is wound around the outside of the film winding shaft (430). The anti-pressure membrane (440) has symmetrically opened membrane grooves (441) on both sides.

2. The preparation process of the porous, dense thermoplastic polyurethane according to claim 1, characterized in that: The polyurethane preparation apparatus includes a pore-forming device (200) suspended in one end of a coagulation bath (120). The pore-forming device (200) includes a spinneret (210) sleeved with a pump hose (110), a pore-forming box (220) snapped into the bottom of the spinneret (210), and an air injection pipe (230) embedded in the top of the pore-forming box (220). The spinneret (210) has an internally hollow trapezoidal structure with an open top. The bottom surface of the spinneret (210) has several rows of nozzles. The air injection pipe (230) is located inside the hole forming box (220). A number of air distribution pipes (231) are connected on both sides of a horizontal radial section. The air distribution pipes (231) are located below the number of rows of spinnerets (211). An air outlet (232) is opened on the bottom surface of the air distribution pipe (231) and directly below the spinnerets (211). A material leakage groove (221) is opened on the bottom surface of the hole forming box (220) and directly below each row of spinnerets (211).

3. The preparation process of the porous, dense thermoplastic polyurethane according to claim 2, characterized in that: The cross-section of the gas distribution pipe (231) is triangular with its apex facing upward. One end of the gas injection pipe (230) is sealed and embedded in the inner wall of the perforation box (220). The other end of the gas injection pipe (230) is connected to the air compressor through a gas pipe. The outer end of the gas distribution pipe (231) is a closed end.

4. The preparation process of the porous dense thermoplastic polyurethane according to claim 3, characterized in that: The bottom surface of the spinneret (210) is symmetrically provided with retaining strips (212) at both ends, and the top surface of the hole forming box (220) is symmetrically provided with inserts (225) that are inserted into the retaining strips (212).

5. The preparation process of the porous dense thermoplastic polyurethane according to claim 4, characterized in that: The bottom surface of the forming box (220) and the front and rear sides of the material discharge trough (221) are vertically welded with wire guide plates (222). The bottom edge of the wire guide plate (222) facing away from the glue storage tank (100) is rotatably connected to the wire guide roller (223). Several wire gathering sleeves (224) are welded between a pair of wire guide plates (222) on the front and rear sides of each material discharge trough (221). The wire gathering sleeves (224) are located directly below the spinneret (211). The height of each pair of wire guide plates (222) gradually decreases from the front to the rear of the forming box (220).

6. The preparation process of the porous dense thermoplastic polyurethane according to claim 5, characterized in that: A sleeve (321) is welded to one radial side of the threaded ring (320), and a rotating column (313) that is inserted into the sleeve (321) is welded to the left and right sides of the top end of the wire feeder (310). A wire pusher block (311) is welded to the middle of the top end of the wire feeder (310), and a roller (361) is rotatably connected to the bottom end of the rotating block (360).

7. The preparation process of the porous dense thermoplastic polyurethane according to claim 6, characterized in that: The bottom rear of the wire feeder (310) is welded with a three-sided diagonal bar (312), and a wire guide shaft (350) is embedded between the three-sided diagonal bars (312) and in front of the wire drawing shaft (340). A number of wire dividing grooves (351) are equally spaced on the outer side of the wire guide shaft (350).

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