Special polyester fiber production equipment and production process for military Kevlar fabric

Abstract

The invention provides polyester fiber production equipment special for military Kevlar fabric and a production process, and relates to the technical field of fiber production. The special polyester fiber production equipment for the military Kevlar fabric comprises a reaction kettle, a diaphragm pump, pressurizing equipment, heating equipment, vacuumizing equipment, a controller, a drain valve and a spinning device. According to the invention, the synergistic effect of axial vortex and radial shearing is realized through the double-shaft differential stirring system, the mixing time of the high-viscosity melt is greatly shortened, the problem of non-uniform distribution of modified monomers caused by traditional single stirring is solved, and the dynamic circulating injection system is used for stirring the melt through high-pressure jet flow disturbance on the melt, so that the high-viscosity melt is obtained. The carboxyl and acylamino functional groups can be induced to be orderly arranged along the stress direction, so that the hydrogen bond distribution density is enhanced, the CV value of the interface peel strength of the polyester fiber is stably controlled within 2.5%, and the layering resistance of the military Kevlar fabric is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber production, in particular to production equipment and a production process of polyester fibers specially used for military Kevlar fabrics. Background Art

[0002] Military Kevlar fiber, with its 3.6 GPa tensile strength and 131 GPa high modulus, has become the gold standard for protective materials. However, its rigid molecular chains result in insufficient fabric flexibility. While the introduction of polyester fiber can improve fabric comfort, conventional polyester and Kevlar fiber exhibit weak interfacial bonding, necessitating in-situ polymerization of the polyester with carboxylic acid-modified monomers (such as isophthalic acid). This introduces carboxyl functional groups at the ends of the molecular chains to enhance hydrogen bonding with the amide groups in the Kevlar fiber.

[0003] Existing polymerization equipment has significant technical defects: the traditional stirring structure uses a single rotation speed (usually 60-80r / min), and it takes more than 90 minutes to mix the high-viscosity melt (800-1000Pa·s). In addition, insufficient axial / radial mixing leads to uneven distribution of the modified monomer, resulting in a widened molecular weight distribution of polyester (PDI>2.1), which reduces the interfacial compatibility with Kevlar fiber.

[0004] To improve the mixing uniformity of polymerization equipment, the prior art discloses a functional polyester production system, production method, and functional polyester fiber (Chinese Patent Publication No. CN114736357A). The functional polyester production system includes a main polyester production system and a continuous functional polyester oligomer production system. The main polyester production system includes an esterification unit, a pre-polycondensation unit, and a final polycondensation unit connected in sequence. The continuous functional polyester oligomer production system includes a continuous reactor with a high-pressure injection device and an oligomer mixer disposed between the esterification unit and the pre-polycondensation unit. Functional powder slurry is injected into the reactor through a slurry inlet by the high-pressure injection device, where it is rapidly and evenly mixed with a portion of the polyester oligomers within the reactor, effectively preventing agglomeration of the functional powder and improving the performance of the functional polyester. The functional polyester produced by this production system has a filter press value (FPPFPV) of no more than 0.2 bar / g, which is beneficial for improving the spinning performance of the functional polyester and is suitable for producing high-quality fibers, films, and other products.

[0005] However, this existing technology has the following technical defects in terms of functional powder dispersion uniformity: 1) High-pressure injection only acts on the oligomer mixing stage and does not cover the entire esterification / polycondensation process of the polyester main production system, resulting in insufficient distribution uniformity of the carboxylic acid-modified monomer in the high viscosity stage of the melt (800-1000 Pa·s), and the measured molecular weight distribution index (PDI) is still as high as 2.0-2.2; 2) It relies on a single mechanical mixing mode and lacks the synergistic effect of axial vortex and radial shear, resulting in insufficient efficiency in breaking agglomerates larger than 20μm (residual rate >2.5%), affecting the subsequent spinning breakage rate; these problems are significantly different from the interfacial bonding strength stability (CV value ≤3%) required for polyester fibers specifically used for military Kevlar fabrics.

[0006] In summary, it is necessary to improve and optimize the production equipment and production process of polyester fiber specially used for military Kevlar fabrics. Summary of the Invention

[0007] In response to the shortcomings of the existing technology, the present invention provides a special polyester fiber production equipment and production process for military Kevlar fabrics, which solves the problem of insufficient distribution uniformity of carboxylic acid modified monomers in the high viscosity stage of the melt caused by the single mixing mode in the special polyester fiber production equipment and production process for military Kevlar fabrics in the existing technology.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: a polyester fiber production device for military Kevlar fabrics, comprising a reactor, a diaphragm pump, a pressurizing device, a heating device, a vacuuming device, a controller, a drain valve and a spinning device, wherein the reactor is supported by multiple sets of feet, the inner wall of the reactor is provided with a jacket layer, the jacket layer is connected to the heating device, the top of the reactor is fixedly connected to a sealing cover, the lower wall of the sealing cover is provided with a temperature detection structure for detecting the temperature inside the reactor, the upper wall of the sealing cover is fixedly connected to a rotating seat, the inner wall of the rotating seat is rotatably connected to a first rotating shaft, the lower end of the first rotating shaft sequentially passes through the inner wall of the rotating seat and the inner wall of the sealing cover and extends into the interior of the reactor, the inner wall of the first rotating shaft is rotatably connected to a second rotating shaft, the The upper and lower ends of the second rotating shaft extend toward the upper and lower sides of the first rotating shaft respectively, and the first rotating shaft and the rotating seat, as well as the second rotating shaft and the first rotating shaft are locked and sealed by a magnetic fluid sealing device. A drive box is fixedly connected to the upper wall of the sealing cover and located on the periphery of the rotating seat. A rotating drive structure for driving the first rotating shaft and the second rotating shaft to rotate is provided inside the drive box. A first stirring structure is provided at one end of the first rotating shaft extending into the interior of the reactor, and a second stirring structure is provided at one end of the second rotating shaft extending to the lower side of the first rotating shaft. The inlet end of the diaphragm pump is fixedly connected to the lower wall of the reactor through a pipeline, a filtering structure is provided on the outer wall of the pipeline between the diaphragm pump and the reactor, and a spray structure for accelerating the mixing of the melt in the reactor is provided between the outlet end of the diaphragm pump and the reactor.

[0009] Preferably, the temperature detection structure includes multiple groups of temperature sensors, and the lower wall of the sealing cover is fixedly connected to multiple groups of mounting seats, which are equally distributed in a circle with the axis of the sealing cover as the center, and the multiple groups of temperature sensors are respectively fixedly connected to the lower wall of a group of mounting seats.

[0010] The circumferentially distributed temperature sensors can synchronously monitor the melt temperature gradient in different areas of the reactor, and combined with the controller to adjust the jacket layer heating power in real time to avoid local overheating that may cause polyester molecular chain breakage, ensuring that the temperature fluctuation of the polycondensation reaction is ≤1.5℃.

[0011] Preferably, the rotation drive structure includes a first motor, a first reducer, a second motor and a second reducer, the first motor, the first reducer, the second motor and the second reducer are all fixedly connected to the upper wall of the sealing cover, the first motor and the first reducer are both located on the left side of the rotating seat, the second motor and the second reducer are both located on the right side of the rotating seat, the output shaft of the first motor is fixedly connected to the input and output shaft of the first reducer, the output shaft of the first reducer is fixedly connected to the first driving gear, the upper end of the first rotating shaft passes through the rotating seat and extends to the upper side of the rotating seat, the end of the first rotating shaft extending to the upper side of the rotating seat is fixedly connected to the first driven gear, the first driven gear and the first driving gear are meshed with each other, the output shaft of the second motor is fixedly connected to the input shaft of the second reducer, the outer wall of the second reducer output shaft is fixedly connected to the second driving gear, the end of the second rotating shaft extending to the upper side of the first rotating shaft is fixedly connected to the second driven gear, and the second driven gear and the second driving gear are meshed with each other.

[0012] A magnetic fluid seal simultaneously isolates volatile gases from the melt to prevent gear corrosion. When the first and second motors operate at a differential speed ratio of 1:3, the dual-shaft differential drive enables the first and second stirring structures to generate a synergistic effect of axial vortex and radial shear, increasing the mixing efficiency to 2.1 times that of conventional single-shaft stirring.

[0013] Preferably, the first stirring structure includes multiple groups of stirring rods, and the multiple groups of stirring rods are asymmetrically fixedly connected to the outer wall of one end of the first rotating shaft extending into the interior of the reactor. The outer walls of the multiple groups of stirring rods are fixedly connected to multiple groups of stirring needles. The stirring rods have an S-shaped structure, the bending curvature radius of the stirring rods is ≥50mm, and the spacing between adjacent stirring rods is 1 / 8-1 / 6 of the diameter of the stirring kettle.

[0014] The asymmetric layout of the S-shaped stirring rod produces an alternating pressure gradient during rotation, forcing the melt to migrate from the kettle wall to the center. Combined with the micro-area shearing effect of the stirring needle, the dispersion uniformity of the carboxylic acid-modified monomer is improved from 92% to 98.5% (HPLC detection), and the polyester molecular weight distribution PDI ≤ 2.0.

[0015] Preferably, the second stirring structure includes two groups of stirring blades, both groups of stirring blades are fixedly connected to one end of the second rotating shaft extending to the lower side of the first rotating shaft, both groups of stirring blades are turbine blades, and the inner walls of both groups of stirring blades are provided with multiple groups of guide holes.

[0016] When the second shaft rotates at a high speed of 1200 rpm, the turbine blade stirring blade releases a high-pressure melt jet through the guide hole, forming counter-convection with the S-shaped stirring rod of the first stirring structure, reducing the residual rate of agglomerates larger than 20 μm from 2.5% to 0.8% and reducing the products of condensation side reactions.

[0017] Preferably, the filtration structure includes a filter, a first filter screen and a second filter screen. The filter is fixedly connected to the outer wall of the pipe between the reactor and the inlet end of the diaphragm pump. The first filter screen and the second filter screen are fixedly connected to the inner wall of the filter in an upper and lower distribution. The pore size of the first filter screen is 20 μm, and the pore size of the second filter screen is 50 μm.

[0018] The 50μm second filter screen preferentially intercepts fiber agglomerates, and the 20μm first filter screen captures tiny gel particles. The two-stage filtration reduces the frequency of clogging of the spinning spinneret in the subsequent process.

[0019] Preferably, the injection structure includes six groups of nozzles, and a diverter is fixedly connected to the front wall of the reactor and near the lower wall. The diverter is a one-inlet and three-outlet structure, and the inlet end of the diverter is fixedly connected to the outlet end of the diaphragm pump through a pipe. The three groups of outlet ends of the diverter are respectively fixedly connected to a group of connecting pipes, and the ends of the three groups of connecting pipes away from the diverter all pass through the side wall of the reactor and extend into the interior of the reactor. The connection points of the three groups of connecting pipes and the reactor are equally distributed in a circle with the axis of the reactor as the center, and the ends of the connecting pipes extending into the interior of the reactor are fixedly connected to two groups of nozzles through a three-way joint. The six groups of nozzles are respectively fixedly connected to the end of a group of nozzles away from the three-way joint. The six groups of nozzles are all close to the upper mouth of the reactor. The two groups of nozzles located on the same three-way joint are arranged with the injection surfaces facing each other, and the nozzles are conical spiral nozzles with an injection angle of 60-75°.

[0020] When the high-pressure melt is ejected through the nozzle, the conical spiral flow channel generates a rotating jet, which causes the melt to form counter-turbulence in the upper part of the reactor. Combined with the stirring structure, the mixing time of the carboxylic acid-modified monomer is greatly shortened.

[0021] Preferably, a pressure sensor for detecting the internal pressure of the connecting pipe is fixedly connected to the outer wall of one end of the connecting pipe extending into the interior of the reactor, and the diverter outlet and the connecting pipe are connected via an electrically controlled flow valve.

[0022] The connecting pipe pressure sensor is linked to the electronically controlled flow valve to ensure that the flow deviation of the six groups of nozzles is ≤5%.

[0023] Preferably, the front wall and the rear wall of the driving box are both provided with heat dissipation windows for facilitating heat dissipation, and the inner side walls of the heat dissipation windows are provided with axial flow fans.

[0024] The axial flow fan forcibly discharges the friction heat of the gears in the drive box, so that the operating temperature of the first motor and the second motor is stabilized at 45-55°C, avoiding the temperature rise causing the reduction of the lubrication performance of the reducer.

[0025] The production process of the polyester fiber production equipment for military Kevlar fabrics is carried out using the above-mentioned polyester fiber production equipment for military Kevlar fabrics. The production process includes the following steps:

[0026] S1. Raw material premixing and sealing and pressurizing: Polyethylene terephthalate and isophthalic acid comonomer are added to the reactor at a mass ratio of 80:20. The transmission gap between the first and second rotating shafts is sealed using a magnetic fluid sealing device. The jacket layer is heated to 280-300°C and the pressure in the reactor is maintained at 0.5-0.8 MPa.

[0027] S2: Gradient stirring and melting. The controller synchronously starts the first and second motors, driving the first shaft at a speed of 120-150 r / min to drive the S-shaped stirring rod for radial shearing. At the same time, the second shaft drives the turbine stirring blade at a speed of 90-110 r / min to generate axial vortex, driving the melt to surge upward. Stirring is continued for 40-60 minutes until the melt viscosity reaches 800-1000 Pa·s.

[0028] S3, Dynamic Circulation Injection: The diaphragm pump is activated to pump the melt from the bottom of the reactor. The melt passes through the first and second filters in sequence to intercept impurities with a particle size greater than 20μm. The melt is then distributed to six groups of conical spiral nozzles via a diverter. The melt stream is sprayed toward the top of the reactor at a pressure of 6-8MPa. The spray angle is 60-75°, and the streams from adjacent nozzles are in a counter-flow pattern, which increases the molecular chain orientation of the melt by 12-15%.

[0029] S4, closed-loop temperature-controlled spinning, uses multiple sets of temperature sensors to monitor the melt temperature fluctuation ≤±1.5°C. When the pressure sensor detects a pressure difference in the connecting pipe greater than 0.3MPa, the controller automatically adjusts the drain valve opening to 70-85%, and finally delivers the homogenized melt to the spinning device for spinning.

[0030] The present invention provides a production device and process for polyester fiber specifically for military Kevlar fabrics. It has the following beneficial effects:

[0031] 1. Compared with existing technologies, this polyester fiber production equipment and production process for military Kevlar fabrics achieves the synergistic effect of axial vortex and radial shear through a dual-axis differential stirring system, greatly shortening the mixing time of high-viscosity melts and solving the problem of uneven distribution of modified monomers caused by traditional single stirring. The uniformity of carboxylic acid modified monomers reaches more than 98.5%, ensuring the molecular weight distribution of polyester (PDI ≤ 2.0) and the interface compatibility with Kevlar fiber.

[0032] 2. Compared with existing technologies, the production equipment and production process of polyester fibers specially used for military Kevlar fabrics are characterized by a dynamic circulation injection system that induces the orderly arrangement of carboxyl and amide functional groups along the stress direction through high-pressure jet disturbance of the melt, thereby enhancing the hydrogen bond distribution density and stably controlling the interfacial peel strength CV value of the polyester fiber to within 2.5%. When producing Kevlar fabrics, the special polyester fiber is brought into contact with the Kevlar fiber through hot pressing or blending processes, and the carboxyl group activity is activated by high-pressure jets, prompting it to form a hydrogen bond network with the amide groups on the surface of the Kevlar fiber, thereby significantly improving the anti-delamination performance of the military Kevlar fabrics. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the structure of the present invention;

[0034] Figure 2 It is a partial cross-sectional view of the top view of the connection structure of the sealing cover, the first motor and the second motor of the present invention;

[0035] Figure 3 For the present invention Figure 2 A partial enlarged view of point A in the middle;

[0036] Figure 4 It is a partial schematic diagram of the connection structure of the first rotating shaft, the second rotating shaft, the first driven gear and the second driven gear of the present invention;

[0037] Figure 5 It is a partial schematic diagram of the connection structure of the first rotating shaft, the second rotating shaft, the stirring rod and the stirring blade of the present invention;

[0038] Figure 6 This is a schematic top view of the internal structure of the reactor of the present invention;

[0039] Figure 7 This is a partial cross-sectional view of the internal structure of the filter of the present invention.

[0040] Among them, 1. base; 2. reactor; 3. sealing cover; 4. drive box; 5. heat dissipation window; 6. filter; 7. diaphragm pump; 8. diverter; 9. first motor; 10. first reducer; 11. second motor; 12. second reducer; 13. rotating seat; 14. first rotating shaft; 15. first driven gear; 16. second rotating shaft; 17. second driven gear; 18. first driving gear; 19. second driving gear; 20. mounting seat; 21. temperature sensor; 22. stirring rod; 23. stirring needle; 24. stirring blade; 25. guide hole; 26. connecting pipe; 27. three-way joint; 28. pressure sensor; 29. ​​nozzle; 30. nozzle; 31. first filter; 32. second filter. DETAILED DESCRIPTION

[0041] 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.

[0042] Example:

[0043] like Figures 1 to 7 As shown, an embodiment of the present invention provides a polyester fiber production device for military Kevlar fabric, including a reactor 2, a diaphragm pump 7, a pressurizing device, a heating device, a vacuuming device, a controller, a drain valve, and a spinning device. The reactor 2 is supported by multiple sets of feet 1. The inner wall of the reactor 2 is provided with a jacket layer, which is connected to the heating device. In this embodiment, the pressurizing device, the heating device, the vacuuming device, the controller, the drain valve, and the spinning device are all existing mature technologies.

[0044] In order to accurately control the polymerization reaction temperature of the high-viscosity melt, a sealing cover 3 is fixedly connected to the top of the reactor 2. The lower wall of the sealing cover 3 is provided with a temperature detection structure for detecting the temperature inside the reactor 2. The temperature detection structure includes multiple groups of temperature sensors 21. The lower wall of the sealing cover 3 is fixedly connected to multiple groups of mounting seats 20. The multiple groups of mounting seats 20 are evenly distributed around the circumference of the sealing cover 3. The multiple groups of temperature sensors 21 are respectively fixedly connected to the lower wall of one group of mounting seats 20.

[0045] The circumferentially distributed temperature sensors 21 can synchronously monitor the melt temperature gradient in different areas of the reactor 2, and adjust the jacket heating power in real time in conjunction with the controller to avoid local overheating that may cause polyester molecular chain breakage, ensuring that the polycondensation reaction temperature fluctuation is ≤1.5°C;

[0046] The second end of the first shaft 14 is connected to the inner wall of the first shaft 14, and the second end of the second shaft 16 is connected to the inner wall of the first shaft 14. The upper and lower ends of the second shaft 16 extend toward the upper and lower sides of the first shaft 14 respectively. The first shaft 14 and the rotating seat 13 are locked and the second shaft 16 and the first shaft 14 are sealed by a magnetic fluid sealing device. The upper wall of the sealing cover 3 and the outer periphery of the rotating seat 13 are fixedly connected to the driving box 4. The driving box 4 is provided with a rotating driving structure for driving the first shaft 14 and the second shaft 16 to rotate; the rotating driving structure includes a first motor 9, a first reducer 10, a second motor 11 and a second reducer 12. 11 and the second reducer 12 are fixedly connected to the upper wall of the sealing cover 3, the first motor 9 and the first reducer 10 are both located on the left side of the rotating seat 13, the second motor 11 and the second reducer 12 are both located on the right side of the rotating seat 13, the output shaft of the first motor 9 is fixedly connected to the input and output shafts of the first reducer 10, the output shaft of the first reducer 10 is fixedly connected to the first driving gear 18, the upper end of the first rotating shaft 14 passes through the rotating seat 13 and extends to the upper side of the rotating seat 13, the end of the first rotating shaft 14 extending to the upper side of the rotating seat 13 is fixedly connected to the first driven gear 15, the first driven gear 15 and the first driving gear 18 are meshed with each other, the output shaft of the second motor 11 is fixedly connected to the input shaft of the second reducer 12, the outer wall of the output shaft of the second reducer 12 is fixedly connected to the second driving gear 19, the end of the second rotating shaft 16 extending to the upper side of the first rotating shaft 14 is fixedly connected to the second driven gear 17, and the second driven gear 17 and the second driving gear 19 are meshed with each other;

[0047] The magnetic fluid seal device simultaneously isolates volatile gases from the melt to prevent gear corrosion. When the first motor 9 and the second motor 11 operate at a differential speed ratio of 1:3, the dual-axis differential drive enables the first and second stirring structures to generate axial vortex and radial shear synergy, increasing the mixing efficiency to 2.1 times that of conventional single-axis stirring.

[0048] To address the problem of mixing dead zones in the center of the high-viscosity melt, a first stirring structure is provided at one end of the first rotating shaft 14 extending into the interior of the reactor 2. The first stirring structure includes multiple groups of stirring rods 22, which are asymmetrically fixedly connected to the outer wall of the end of the first rotating shaft 14 extending into the interior of the reactor 2. Multiple groups of stirring pins 23 are fixedly connected to the outer walls of the multiple groups of stirring rods 22. The stirring rods 22 have an S-shaped structure, a curvature radius of ≥50 mm, and the spacing between adjacent stirring rods 22 is 1 / 6 of the diameter of the stirring reactor.

[0049] The asymmetric layout of the S-shaped stirring rod 22 generates an alternating pressure gradient during rotation, forcing the melt to migrate from the reactor wall to the center. Combined with the micro-area shearing effect of the stirring needle 23, the dispersion uniformity of the carboxylic acid modified monomer is improved from 92% to 98.5% (HPLC detection), and the molecular weight distribution (PDI) of the polyester is ≤2.0.

[0050] In order to eliminate melt stratification and accelerate axial convection, a second stirring structure is provided at one end of the second rotating shaft 16 extending from the lower side of the first rotating shaft 14. The second stirring structure includes two sets of stirring blades 24. Both sets of stirring blades 24 are fixedly connected to the end of the second rotating shaft 16 extending from the lower side of the first rotating shaft 14. Both sets of stirring blades 24 are turbine blades, and the inner walls of both sets of stirring blades 24 are provided with multiple sets of guide holes 25.

[0051] When the second rotating shaft 16 rotates at a high speed of 1200 rpm, the turbine blade stirring blade 24 releases a high-pressure melt jet through the guide hole 25, forming a counter-current with the S-shaped stirring rod 22 of the first stirring structure, reducing the residual rate of agglomerates larger than 20 μm from 2.5% to 0.8% and reducing the condensation side reaction products;

[0052] In order to intercept unreacted monomers and mechanical impurities, the inlet end of the diaphragm pump 7 is fixedly connected to the lower wall of the reactor 2 through a pipe. The outer wall of the pipe between the diaphragm pump 7 and the reactor 2 is provided with a filtering structure, which includes a filter 6, a first filter screen 31 and a second filter screen 32. The filter 6 is fixedly connected to the outer wall of the pipe between the reactor 2 and the inlet end of the diaphragm pump 7. The first filter screen 31 and the second filter screen 32 are fixedly connected to the inner wall of the filter 6 in an upper and lower distribution. The pore size of the first filter screen 31 is 20 μm, and the pore size of the second filter screen 32 is 50 μm.

[0053] The 50μm second filter 32 preferentially intercepts fiber agglomerates, while the 20μm first filter 31 captures tiny gel particles. The two-stage filtration reduces the frequency of spinneret blockage in the subsequent process.

[0054] In order to achieve forced circulation of the melt and directional arrangement of functional groups, an injection structure for accelerating the mixing of the melt in the reactor 2 is provided between the outlet end of the diaphragm pump 7 and the reactor 2. The injection structure includes six groups of nozzles 30. A diverter 8 is fixedly connected to the front wall of the reactor 2 and close to the lower wall. The diverter 8 is a one-inlet and three-outlet structure. The inlet end of the diverter 8 is fixedly connected to the outlet end of the diaphragm pump 7 through a pipeline. The three groups of outlet ends of the diverter 8 are respectively fixedly connected to a group of connecting pipes 26. The ends of the three groups of connecting pipes 26 away from the diverter 8 all penetrate the side wall of the reactor 2 and extend into the interior of the reactor 2. The connection points of the three groups of connecting pipes 26 with the reactor 2 are circumferential with the axis of the reactor 2 as the center. The connecting pipe 26 is equally distributed, and one end extending into the interior of the reactor 2 is fixedly connected to two groups of nozzles 29 through a three-way joint 27. Six groups of nozzles 30 are respectively fixedly connected to one end of a group of nozzles 29 away from the three-way joint 27. The six groups of nozzles 30 are all close to the upper opening of the reactor 2. The two groups of nozzles 30 located on the same three-way joint 27 are arranged with their spraying surfaces facing each other. The nozzles 30 are conical spiral nozzles with a spraying angle of 60-75°. The outer wall of the end of the connecting pipe 26 extending into the interior of the reactor 2 is fixedly connected to a pressure sensor 28 for detecting the internal pressure of the connecting pipe 26. The outlet of the diverter 8 is connected to the connecting pipe 26 through an electrically controlled flow valve.

[0055] When the high-pressure melt is ejected through the nozzle 30, the conical spiral flow channel generates a rotating jet, which promotes the formation of counter-turbulent flow in the upper part of the reactor 2. Combined with the stirring structure, the mixing time of the carboxylic acid-modified monomer is shortened from 90 minutes to 48 minutes. The pressure sensor 28 of the connecting pipe 26 is linked to the electronically controlled flow valve to ensure that the flow deviation of the six groups of nozzles 30 is ≤5%.

[0056] In order to prevent the drive box 4 from overheating and causing gear transmission failure, the front wall and rear wall of the drive box 4 are provided with heat dissipation windows 5 for convenient heat dissipation, and the inner wall of the heat dissipation window 5 is provided with an axial flow fan;

[0057] The production process of the polyester fiber production equipment for military Kevlar fabrics is carried out using the above-mentioned polyester fiber production equipment for military Kevlar fabrics. The production process includes the following steps:

[0058] S1. Raw material premixing and sealing and pressurizing: Polyethylene terephthalate and isophthalic acid comonomer are added to reactor 2 at a mass ratio of 80:20. The transmission gap between the first rotating shaft 14 and the second rotating shaft 16 is sealed by a magnetic fluid sealing device. The jacket layer is heated to 280-300°C and the pressure in the reactor is maintained at 0.5-0.8 MPa.

[0059] S2: Gradient stirring and melting. The controller synchronously starts the first motor 9 and the second motor 11, driving the first rotating shaft 14 at a speed of 120-150 r / min to drive the S-shaped stirring rod 22 to perform radial shearing. At the same time, the second rotating shaft 16 drives the turbine stirring blade 24 at a speed of 90-110 r / min to generate axial vortex, driving the melt to surge upward. Stirring is continued for 40-60 minutes until the melt viscosity reaches 800-1000 Pa·s.

[0060] S3, dynamic circulation injection: The diaphragm pump 7 is started to pump the melt from the bottom of the reactor 2. The melt passes through the first filter 31 and the second filter 32 in sequence to intercept impurities with a particle size greater than 20 μm. The melt is then distributed to six groups of conical spiral nozzles 30 via the diverter 8. The melt streams are sprayed toward the upper part of the reactor 2 at a pressure of 6-8 MPa. The spray angle is 60-75°, and the streams from adjacent nozzles are in a counter-flow mode, which increases the molecular chain orientation of the melt by 12-15%.

[0061] In S4, closed-loop temperature-controlled spinning, multiple sets of temperature sensors 21 monitor the melt temperature fluctuation to ≤±1.5°C. When the pressure sensor 28 detects a pressure difference in the connecting pipe 26 greater than 0.3 MPa, the controller automatically adjusts the opening of the drain valve to 70-85%, and finally delivers the homogenized melt to the spinning device for spinning.

[0062] Working principle: The circumferentially distributed temperature sensors 21 can synchronously monitor the melt temperature gradient in different areas of the reactor 2, and adjust the jacket layer heating power in real time in combination with the controller to avoid local overheating that causes polyester molecular chain breakage, ensuring that the temperature fluctuation of the polycondensation reaction is ≤1.5°C; the magnetic fluid sealing device synchronously isolates the volatile gas of the melt to avoid gear corrosion. When the first motor 9 and the second motor 11 are respectively operated at a differential speed ratio of 1:3, the dual-axis differential drive enables the first stirring structure and the second stirring structure to produce axial vortex and radial shear synergistic effects, and the mixing efficiency is increased to 2.1 times that of conventional single-axis stirring; the asymmetric layout of the S-shaped stirring rod 22 generates an alternating pressure gradient during rotation, forcing the melt to migrate from the reactor wall to the center, combined with the micro-area shearing effect of the stirring needle 23, the dispersion uniformity of the carboxylic acid modified monomer is increased from 92% to 98.5% (HPLC detection), and the polyester molecular weight distribution PDI ≤2.0; when the second rotating shaft 16 rotates at a high speed of 1200rpm, the turbine blades The stirring blades 24 release high-pressure melt jets through the guide holes 25, creating countercurrent convection with the S-shaped stirring rods 22 of the first stirring structure. This reduces the residual rate of aggregates larger than 20 μm from 2.5% to 0.8% and reduces polycondensation side reaction products. The 50 μm second filter 32 preferentially intercepts fiber agglomerates, while the 20 μm first filter 31 captures tiny gel particles. This two-stage filtration reduces the frequency of spinneret blockage in subsequent spinning processes. When the high-pressure melt is ejected through the nozzle 30, the conical spiral flow channel generates a rotating jet, which promotes counter-turbulent flow of the melt above the reactor 2. Combined with the stirring structure, this reduces the mixing time of the carboxylic acid-modified monomer from 90 minutes to 48 minutes. The pressure sensor 28 in the connecting pipe 26 is linked to the electronically controlled flow valve to ensure that the flow deviation of the six nozzle groups 30 is ≤5%. The axial flow fan forcibly dissipates friction heat from the gears within the drive box 4, maintaining a stable operating temperature of the first motor 9 and the second motor 11 at 45-55°C, preventing temperature rise from degrading the reducer's lubrication performance.

[0063] While embodiments of the present invention have been shown and described, it will be appreciated 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 defined by the appended claims and their equivalents.

Claims

1. Polyester fiber production equipment for military Kevlar fabrics, characterized by: The invention comprises a reactor (2), a diaphragm pump (7), a pressurizing device, a heating device, a vacuum pumping device, a controller, a liquid discharge valve and a spinning device, wherein the reactor (2) is supported by multiple groups of feet (1), the inner wall of the reactor (2) is provided with a jacket layer, the jacket layer is connected to the heating device, the top of the reactor (2) is fixedly connected with a sealing cover (3), the lower wall of the sealing cover (3) is provided with a temperature detection structure for detecting the temperature inside the reactor (2), the upper wall of the sealing cover (3) is fixedly connected with a rotating seat (13), the inner wall of the rotating seat (13) is rotatably connected with a first rotating shaft (14), the lower end of the first rotating shaft (14) sequentially passes through the inner wall of the rotating seat (13) and the inner wall of the sealing cover (3) and extends into the interior of the reactor (2), the inner wall of the first rotating shaft (14) is rotatably connected with a second rotating shaft (16), the upper and lower ends of the second rotating shaft (16) respectively extend toward the upper and lower sides of the first rotating shaft (14) The first rotating shaft (14) and the rotating seat (13) are extended and locked, and the second rotating shaft (16) and the first rotating shaft (14) are sealed by a magnetic fluid sealing device. The upper wall of the sealing cover (3) is fixedly connected to a driving box (4) located on the periphery of the rotating seat (13). The driving box (4) is provided with a rotating driving structure for driving the first rotating shaft (14) and the second rotating shaft (16) to rotate. The end of the first rotating shaft (14) extending into the interior of the reactor (2) is provided with a first stirring structure, and the end of the second rotating shaft (16) extending to the lower side of the first rotating shaft (14) is provided with a second stirring structure. The inlet end of the diaphragm pump (7) is fixedly connected to the lower wall of the reactor (2) through a pipeline. The outer wall of the pipeline between the diaphragm pump (7) and the reactor (2) is provided with a filtering structure. The outlet end of the diaphragm pump (7) and the reactor (2) is provided with a spraying structure for accelerating the mixing of the melt in the reactor (2).

2. The polyester fiber production equipment for military Kevlar fabric according to claim 1, characterized in that: The temperature detection structure includes multiple groups of temperature sensors (21), and the lower wall of the sealing cover (3) is fixedly connected to multiple groups of mounting seats (20). The multiple groups of mounting seats (20) are equally distributed in a circle with the axis of the sealing cover (3) as the center, and the multiple groups of temperature sensors (21) are respectively fixedly connected to the lower wall of one group of mounting seats (20).

3. The polyester fiber production equipment for military Kevlar fabric according to claim 2, characterized in that: The rotary drive structure comprises a first motor (9), a first reducer (10), a second motor (11) and a second reducer (12); the first motor (9), the first reducer (10), the second motor (11) and the second reducer (12) are all fixedly connected to the upper wall of the sealing cover (3); the first motor (9) and the first reducer (10) are both located on the left side of the rotating seat (13); the second motor (11) and the second reducer (12) are both located on the right side of the rotating seat (13); the output shaft of the first motor (9) is fixedly connected to the input and output shaft of the first reducer (10); the output shaft of the first reducer (10) is fixedly connected to the first driving gear (18); the first rotating shaft The upper end of the shaft (14) passes through the rotating seat (13) and extends to the upper side of the rotating seat (13). The end of the first rotating shaft (14) extending to the upper side of the rotating seat (13) is fixedly connected to the first driven gear (15). The first driven gear (15) and the first driving gear (18) are meshed with each other. The output shaft of the second motor (11) is fixedly connected to the input shaft of the second reducer (12). The outer wall of the output shaft of the second reducer (12) is fixedly connected to the second driving gear (19). The end of the second rotating shaft (16) extending to the upper side of the first rotating shaft (14) is fixedly connected to the second driven gear (17). The second driven gear (17) and the second driving gear (19) are meshed with each other.

4. The polyester fiber production equipment for military Kevlar fabric according to claim 3, characterized in that: The first stirring structure comprises a plurality of stirring rods (22), wherein the plurality of stirring rods (22) are fixedly connected in an asymmetrical manner to the outer wall of one end of the first rotating shaft (14) extending into the interior of the reactor (2), and the outer walls of the plurality of stirring rods (22) are fixedly connected to a plurality of stirring needles (23), wherein the stirring rods (22) are in an S-shaped structure, the bending radius of the stirring rods (22) is ≥50 mm, and the spacing between adjacent stirring rods (22) is 1 / 8-1 / 6 of the diameter of the reactor.

5. The polyester fiber production equipment for military Kevlar fabric according to claim 4, characterized in that: The second stirring structure comprises two groups of stirring blades (24), both groups of stirring blades (24) are fixedly connected to one end of the second rotating shaft (16) extending to the lower side of the first rotating shaft (14), both groups of stirring blades (24) are turbine blades, and the inner walls of the two groups of stirring blades (24) are provided with multiple groups of guide holes (25).

6. The polyester fiber production equipment for military Kevlar fabric according to claim 5, characterized in that: The filtering structure comprises a filter (6), a first filter screen (31) and a second filter screen (32); the filter (6) is fixedly connected to the outer wall of the pipe between the reactor (2) and the inlet end of the diaphragm pump (7); the first filter screen (31) and the second filter screen (32) are fixedly connected to the inner wall of the filter (6) in an upper and lower distribution; the first filter screen (31) has a pore size of 20 μm, and the second filter screen (32) has a pore size of 50 μm.

7. The polyester fiber production equipment for military Kevlar fabric according to claim 6, characterized in that: The injection structure includes six groups of nozzles (30). A diverter (8) is fixedly connected to the front wall of the reactor (2) and near the lower wall. The diverter (8) is a one-inlet and three-outlet structure. The inlet end of the diverter (8) is fixedly connected to the outlet end of the diaphragm pump (7) through a pipeline. The three groups of outlet ends of the diverter (8) are respectively fixedly connected to a group of connecting pipes (26). The ends of the three groups of connecting pipes (26) away from the diverter (8) all pass through the side wall of the reactor (2) and extend into the interior of the reactor (2). The connection points of the three groups of connecting pipes (26) and the reactor (2) are connected to the reactor (2). The reactor (2) is circumferentially and evenly distributed with the axis of the reactor (2) as the center. One end of the connecting pipe (26) extending into the interior of the reactor (2) is fixedly connected to two groups of nozzles (29) through a three-way joint (27). The six groups of nozzles (30) are respectively fixedly connected to one end of a group of nozzles (29) away from the three-way joint (27). The six groups of nozzles (30) are all close to the upper mouth of the reactor (2). Among the six groups of nozzles (30), two groups located on the same three-way joint (27) are arranged with their injection surfaces facing each other. The nozzles (30) are conical spiral injection heads with an injection angle of 60-75°.

8. The polyester fiber production equipment for military Kevlar fabric according to claim 7, characterized in that: A pressure sensor (28) for detecting the internal pressure of the connecting pipe (26) is fixedly connected to the outer wall of one end of the connecting pipe (26) extending into the interior of the reactor (2), and the outlet of the diverter (8) and the connecting pipe (26) are connected via an electrically controlled flow valve.

9. The polyester fiber production equipment for military Kevlar fabric according to claim 8, characterized in that: The front wall and the rear wall of the drive box (4) are both provided with heat dissipation windows (5) for facilitating heat dissipation, and an axial flow fan is provided on the inner side wall of the heat dissipation window (5).

10. A production process for a polyester fiber production device for military Kevlar fabrics, wherein the production process is carried out using the polyester fiber production device for military Kevlar fabrics as claimed in any one of claims 1 to 9, characterized in that: The production process comprises the following steps: S1. Premixing of raw materials and sealing and pressurizing. Polyethylene terephthalate and isophthalic acid comonomer are added into the reactor (2) at a mass ratio of 80:

20. The transmission gap between the first rotating shaft (14) and the second rotating shaft (16) is sealed by a magnetic fluid sealing device. The jacket layer is heated to 280-300°C and the pressure in the reactor is maintained at 0.5-0.8 MPa. ‌S2, gradient stirring and melting‌, the first motor (9) and the second motor (11) are synchronously started by the controller, the first rotating shaft (14) is driven to drive the S-shaped stirring rod (22) at a speed of 120-150 r / min to perform radial shearing, and at the same time the second rotating shaft (16) is driven to drive the turbine stirring blade (24) at a speed of 90-110 r / min to generate an axial vortex, driving the melt to surge upward, and stirring is continued for 40-60 minutes until the melt viscosity reaches 800-1000 Pa·s; S3, dynamic cycle injection, start the diaphragm pump (7) to extract the melt from the bottom of the reactor (2), pass through the first filter (31) and the second filter (32) in turn to intercept impurities with a particle size greater than 20 μm, and distribute to six groups of conical spiral nozzles (30) through the diverter (8), and spray the melt stream to the upper part of the reactor (2) at a pressure of 6-8 MPa. The spray angle is 60-75° and the adjacent nozzle streams are in a counter-flow mode, so that the orientation degree of the melt molecular chain is increased by 12-15%; ‌S4, closed-loop temperature-controlled spinning‌, monitors the melt temperature fluctuation ≤±1.5°C through multiple sets of temperature sensors (21). When the pressure sensor (28) detects that the pressure difference in the connecting pipe (26) is greater than 0.3MPa, the controller automatically adjusts the opening of the drain valve to 70-85%, and finally delivers the homogeneous melt to the spinning device for spinning.

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