A tow collection system and method for preparing para-aramid staple fibers

Abstract

The present application provides a tow collection system for preparing para-aramid staple fibers, which includes: a PPTA and concentrated sulfuric acid dissolving device, a degassing device, a filtering device, a spinning device, a washing device, a bundling-drying device, and a wire collecting device, wherein the wire collecting device includes a wire feeding device and a wire holding box, and the wire holding box is arranged below the discharge port of the wire feeding device, and the wire holding box reciprocates forward, backward, left, and right relative to the discharge port of the wire feeding device. The present application can achieve that the broken wires in the working process will be taken away by the whole bundle of fibers by continuous bundling and drying, thereby reducing the failure rate of the working process. The fibers are transported to the packaging box through the feeding device, and under the longitudinal force of gravity and the lateral force of the reciprocating motion of the wire holding box, the silk ribbons will begin to be stacked and placed in the wire holding box at the bottom of the wire holding box. The present application can achieve continuous production without the need for an unwinding process, which greatly improves the preparation efficiency of staple fibers.

Description

Technical Field

[0001] The present application belongs to the technical field of para-aramid processing, and relates to a tow collection system and method for preparing para-aramid staple fibers. Background Art

[0002] Para-aramid staple fiber has the characteristics of low density, high temperature resistance, cut resistance, flame retardancy, good thermal stability, and excellent mechanical properties. It has been widely used in national defense and military industry, friction and sealing materials, sports materials, rubber and other fields.

[0003] The existing staple fiber preparation process is through concentrated sulfuric acid and PPTA dissolution, degassing device, filtering device, spinning device, washing device, drying, oiling, winding, and then unwinding, degreasing, drying and short cutting of the para-aramid staple fiber.

[0004] The fiber denier required for short fibers is 1.0-4.0D, and the fiber above 300000D is a strand. Since the conventional method of collecting tows is usually winding, the overall efficiency of preparing para-aramid short fibers is reduced.

[0005] The patent disclosure document (CN102926068A) discloses "a method for curling para-aramid staple fibers". In the patent disclosure document, the aramid filaments are bundled and heated before entering a mechanical stuffing crimping box for curling. After curling, the curled fibers are placed in an oven for drying at 80-140°C to complete the collection of the aramid filaments. The patent bundles the entire tow and then mixes and dries it, which has a poor drying effect and also affects the quality of the tow. In addition, curling and unwinding are required, resulting in low efficiency in preparing staple fibers.

[0006] The patent disclosure document (CN110067127A) discloses "a method for preparing dipped aramid staple fibers", which includes the following processing steps for the aramid raw yarn: A: one bath; B: first drying; C: two baths; D: secondary drying; E: winding; F: cutting; in this patent disclosure document, the staple fibers are also prepared by winding, unwinding and cutting, resulting in low efficiency.

[0007] In summary, the shortcomings of short fibers in existing technical indicators are:

[0008] 1. The existing technology can only produce small rolls of fiber first, and then produce short fibers by unwinding, which is inefficient and wastes manpower and material resources;

[0009] 2. It must go through the winding and unwinding process, which is cumbersome. Failure in the winding and unwinding process will directly affect the output.

[0010] 3. Both the first and second steps involve a drying process, and the fiber needs to be dried before and after, which consumes a lot of energy. Summary of the invention

[0011] In order to solve the problems existing in the background technology, the present application provides a tow collection system and a tow collection method for preparing para-aramid staple fibers. The present application completes drying during the tow bundling process, can realize continuous production, and does not require an unwinding process, which greatly improves the preparation efficiency of the staple fibers. The present application is specifically implemented through the following technical solutions.

[0012] The present application provides a tow collection system for preparing para-aramid staple fibers, which comprises, in sequence: a PPTA and concentrated sulfuric acid dissolving device, a degassing device, a filtering device, a spinning device, a washing device, a bundling-drying device, and a wire collecting device, wherein the wire collecting device comprises a wire feeding device and a wire holding box, wherein the wire holding box is arranged below a discharge port of the wire feeding device, and the wire holding box reciprocates forward, backward, left, and right relative to the discharge port of the wire feeding device.

[0013] In the present application, the devices for preparing para-aramid staple fibers mainly include PPTA and concentrated sulfuric acid dissolving devices, degassing devices, filtering devices, spinning devices, washing devices, bundling-drying devices, and wire collecting devices, among which PPTA and concentrated sulfuric acid dissolving devices, degassing devices, filtering devices, spinning devices, and washing devices are conventional para-aramid fiber preparation devices. The difference between the present application and the prior art mainly lies in the bundling-drying devices and wire collecting devices after water washing, among which the wire collecting device of the present application includes a wire feeding device and a wire collecting box, and the wire collecting box is arranged below the discharge port of the wire feeding device, and the wire collecting box reciprocates forward, backward, left, and right relative to the discharge port of the wire feeding device. In the wire collecting device, under the longitudinal force of gravity and the lateral force of the reciprocating motion of the wire collecting box, the para-aramid fibers begin to be stacked and placed in the wire collecting box at the bottom of the wire collecting box. The ribbons in the wire collecting box can be used as ribbons for preparing staple fibers.

[0014] After the para-aramid fiber tow is bundled and dried, it forms a ribbon that can be used to prepare short fibers, and the ribbon is stacked and placed in the collection box, realizing the continuous production of para-aramid ribbon. When preparing single fibers, there is no need for unwinding process, which greatly improves the preparation efficiency of para-aramid ribbon for short fibers. In addition, during the bundling and drying process, the broken fibers in the tow will be taken away by the whole bundle of fibers, reducing the failure rate of the working process and realizing continuous production.

[0015] As a preferred technical solution of the bundling-drying device of the present application, the bundling-drying device is a multi-stage bundling-drying device which is sequentially arranged in series along the moving direction of the filament bundles.

[0016] After the spinning of para-aramid is completed, the para-aramid filament bundle is relatively thin, but the diameter of the ribbon used for the preparation of staple fibers is much larger than the diameter of the filament bundle. Therefore, in order to form the filament bundle into a ribbon, multiple bundling operations are required, and the bundled ribbon must be dried at the same time. Therefore, the bundling-drying device described in the present application is a multi-stage bundling-drying device arranged in series along the direction of movement of the filament bundle.

[0017] Furthermore, in the multi-stage bundling-drying device, the number of the preceding-stage bundling-drying devices is multiple times the number of the succeeding-stage bundling-drying devices.

[0018] Furthermore, the bundling-drying device comprises:

[0019] Clustering device,

[0020] The drying device is arranged behind the bundling device, and comprises a plurality of wire winding rollers arranged in a box body, and a steam drying device is arranged in the box body.

[0021] As a preferred embodiment of the wire feeding device described in the present application, the wire feeding device includes a wire guide roller and two wire feeding rollers moving toward each other below the wire guide roller, wherein both of the wire feeding rollers are tangent to the fed silk ribbon.

[0022] The ribbon is guided between two wire feeding rollers by the wire guide roller, and the wire feeding rollers are tangent to the fed ribbon, so that the bundled ribbon is continuously fed into the wire box.

[0023] Furthermore, in order to solve the problem that the fiber ribbons are not stacked tightly but loosely in the silk box, resulting in knots inside the silk box, the present application also arranges a pressure plate assembly above the silk box that can move up and down in the silk box. After the silk box moves back and forth and left and right for a specific period of time, the pressure plate assembly descends to press the stacked fiber ribbons tightly, so that the ribbons are stacked layer by layer in the silk box.

[0024] Furthermore, in order to compress or compact the silk strips in the silk box, the pressing plate assembly is provided on at least one side edge of the silk box, such as on the left side, the right side, the front side, and the rear side.

[0025] The present application also provides a method for collecting tows for preparing aramid staple fibers, which comprises the steps of concentrated sulfuric acid and dissolving PPTA, degassing, filtering, spinning, washing, bundling, drying, and collecting, wherein the bundling, drying, and collecting preparation steps are:

[0026] S1. Bundling and drying: Bundling n aramid fiber bundles into one ribbon bundle, specifically,

[0027] S11, performing multi-stage bundling and drying on the washed a aramid yarn to form a yarn bundle, wherein the number of bundling-drying devices in the first stage is multiple times the number of bundling-drying devices in the second stage.

[0028] S12, performing multi-stage bundling and drying in step S11 to obtain a para-aramid ribbon, wherein the moisture content of the obtained para-aramid ribbon is 10% to 20%.

[0029] S2. Silk collection: When the bundled silk ribbons are fed into the silk box through the wire feeding device, the silk ribbons are stacked in the silk box under the action of gravity and the force of the reciprocating motion of the silk box.

[0030] As a preferred technical solution of step S1 of the tow collection method for preparing aramid staple fibers in the present application, the first drying process has a drying steam pressure of 0.5 MPa and a drying temperature of 120-140° C.; the second drying process has a drying steam pressure of 1 MPa and a drying temperature of 80-100° C. The water content is controlled at 10%-20%, the electrostatic effect of fibers with high water content is reduced, and oiling agent is not required to reduce the electrostatic effect of fibers, and fibers with high water content have good bundling properties.

[0031] Furthermore, the drying method in step S1 is one of electric heating rollers, steam and the like.

[0032] The outstanding technical effects of this application are:

[0033] 1. After the para-aramid fiber tow is bundled and dried, it forms a ribbon that can be used to prepare short fibers, and the ribbon is stacked and placed in the collection box, realizing the continuous production of para-aramid ribbon. When preparing single fibers, there is no need for unwinding process, which greatly improves the preparation efficiency of para-aramid ribbon for short fibers. In addition, during the bundling and drying process, the broken fibers in the tow will be taken away by the whole bundle of fibers, reducing the failure rate of the working process, realizing continuous production, and the spinning speed can be increased by 500-800m / min, which can be mass-produced.

[0034] 2. In the present application, the water content is controlled at 10%-20%. The electrostatic effect of fibers with high water content is reduced, and oil agent is not required to reduce the electrostatic effect of fibers. Fibers with high water content have good bundling properties.

[0035] 3. The wire collecting device of the present application includes a wire feeding device and a wire holding box. The wire holding box is arranged below the discharge port of the wire feeding device. The wire holding box reciprocates forward, backward, left and right relative to the discharge port of the wire feeding device. The para-aramid is in the wire collecting device. Under the action of the longitudinal force of gravity and the lateral force of the reciprocating motion of the wire holding box, the silk ribbons will be regularly stacked in the packaging box. The present application uses a feeding machine instead of a winding machine to save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 , a schematic structural diagram of a tow collection system for preparing para-aramid staple fibers provided in an embodiment of the present application;

[0038] Figure 2 , another structural schematic diagram of a tow collection system for preparing para-aramid staple fibers provided in an embodiment of the present application;

[0039] Figure 3 , a schematic diagram of a bundling-drying device in a tow collection system for preparing para-aramid staple fibers provided in an embodiment of the present application;

[0040] Figure 4 , a schematic diagram of a wire feeding device in a tow collection system for preparing para-aramid staple fibers provided in an embodiment of the present application;

[0041] Figure 5 , a schematic diagram of a reciprocating device for collecting filaments in a filament collection system for preparing para-aramid staple fibers provided in an embodiment of the present application,

[0042] Figure 6 , a schematic diagram of the motion route of the wire-receiving reciprocating device provided in the embodiment of the present application,

[0043] Figure 7 , a schematic diagram of a pressure plate assembly provided in an embodiment of the present application.

[0044] In the figure, a water washing device 1, a bundling-drying device 2, a bundling device 201, a drying device 202, a box 2021, a wire winding roller 2022, a steam drying device 2023,

[0045] Wire feeding device 31, wire guide roller 311, wire feeding roller 312,

[0046] Wire collecting device 3, wire storage box 32, discharge port 33,

[0047] The wire reciprocating device 35, the left-right moving device 351, the front-back moving device 352, the receiving plate 3511, the sliding wheel 3512, the transverse track 3521, the roller 3522, the driving motor 3523, the drag chain 3524,

[0048] The pressing plate assembly 36, the pressing plate 361, the lifting device 362, the screw rod 3621, the sliding rod 3622, the screw rod 3623, the lifting motor 3624, the bracket 363,

[0049] Para-aramid fibers, ribbons. DETAILED DESCRIPTION

[0050] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0051] The inventor of this application is engaged in the research of para-aramid staple fiber preparation technology. In actual work, it is found that the shortcomings of the short fibers of the existing technical indicators are as follows: the existing technology can only produce small rolls of fibers first, and then produce short fibers by unwinding, which is inefficient and wastes manpower and material resources; it must go through the winding and unwinding process, which is cumbersome, and failures in the winding and unwinding process will directly affect the output. The first and second steps both have a drying process, and the fibers need to be dried before and after, which consumes a lot of energy.

[0052] In order to solve the above problems, the inventor of the present application proposed a new tow collection system for preparing para-aramid staple fibers. The technical solution of the present application is described in detail below through the specific embodiments and implementation methods of the present application.

[0053] Please refer to 1~ Figure 7 The diagram shows a tow collecting system for preparing para-aramid staple fibers, which comprises, in sequence: a PPTA and concentrated sulfuric acid dissolving device, a degassing device, a filtering device, a spinning device, a water washing device 1, a bundling-drying device 2, and a wire collecting device 3, wherein the wire collecting device 3 comprises a wire feeding device 31 and a wire receiving box 32, wherein the wire receiving box 32 is arranged below a discharge port 33 of the wire feeding device 31, and the wire receiving box 32 reciprocates forward, backward, left, and right relative to the discharge port 33 of the wire feeding device 31.

[0054] In this embodiment, the PPTA and concentrated sulfuric acid dissolving device is used to dissolve the para-aramid PPTA in concentrated sulfuric acid. The degassing device is used to remove the bubbles generated by the dissolution of PPTA in concentrated sulfuric acid, and the filtering device is used to filter the particulate matter or impurities in the PPTA concentrated sulfuric acid solution. The spinning device is used to spin the PPTA dissolved in concentrated sulfuric acid into para-aramid bundles. The washing device 1 is used to wash away the sulfuric acid solvent on the para-aramid bundles, the bundling-drying device 2 is used to bundle and dry multiple bundles of para-aramid, so that the para-aramid bundles are bundled into para-aramid ribbons, and the collecting device 3 is used to collect the para-aramid bundled into ribbons. The PPTA and concentrated sulfuric acid dissolving device, the degassing device, the filtering device, the spinning device, and the washing device are general preparation devices for para-aramid fibers.

[0055] In this embodiment, the wire collecting device includes a wire feeding device 31 and a wire box 32. The wire box 31 is arranged below the discharge port 33 of the wire feeding device. The wire box 32 performs forward, backward, left and right reciprocating motion relative to the discharge port of the wire feeding device. The driving force for the forward, backward, left and right reciprocating motions comes from the front and rear motion devices and the left and right motion devices, respectively, which can be the wheel group motion devices of the front and rear motion devices and the wheel group devices of the left and right motions. The power of the front and rear motion devices and the left and right motion devices is independent. The installation method of the front and rear motion devices and the left and right motion devices is to stack them up and down. The wheel group device can be a device that can realize movement, such as a pulley rail or a screw rod motion.

[0056] The specific motion path can be set with the front, back, left and right endpoints being A, B, C, and D respectively, and the motion trajectory of the silk box being A→B→C→D→C→A→B→C... and so on, in a reciprocating cycle.

[0057] Through this device, under the longitudinal force of gravity and the lateral force of the reciprocating motion of the silk box, the para-aramid ribbons will start at the bottom of the silk box and be stacked in the silk box. The ribbons in the silk box can be used as ribbons for preparing short fibers.

[0058] It can be seen that in the tow collection system for preparing para-aramid staple fibers of this embodiment, the fibers are transported to the packaging box through the feeding device, and the packaging box stacks the fibers regularly in the packaging box by moving back and forth and left and right. Using a feeding machine instead of a winding machine can significantly improve efficiency.

[0059] The system comprises in sequence: a PPTA and concentrated sulfuric acid dissolving device, a degassing device, a filtering device, a spinning device, a water washing device, a bundling-drying device, and a wire collecting device. Through the above devices, continuous production can be realized. The water washing, bundling-drying device, and wire collecting device can be synchronized with spinning. The spinning speed can be increased by 500-800m / min, thereby improving production efficiency.

[0060] As a preferred embodiment of the bundle-drying device 2 of the present application, the bundle-drying device 2 is a multi-stage bundle-drying device arranged in series along the moving direction of the tow. Figure 1 The bundle-drying device is a multi-stage bundle-drying device. After the 48 para-aramid fibers of the spinning device are washed by the washing device 1, they continue to pass through the primary bundle-drying device 21, and the 48 para-aramid fibers are bundled into 24 para-aramid fiber bundles. After passing through the secondary bundle-drying device 22, the 24 bundles of para-aramid fibers are bundled into 12 bundles of para-aramid fiber bundles, and so on, until the bundles are bundled into one para-aramid fiber ribbon, the ribbon can be stacked in the fiber box 32 through the fiber collecting device 3.

[0061] In another optional embodiment, 2 to 4 filaments or filament bundles are bundled into one filament bundle each time, specifically: after the 48 para-aramid filaments of the spinning device are washed by the washing device 1, the 48 para-aramid filaments are bundled into 16 para-aramid filament bundles after passing through the first-level bundling-drying device 21, and then the 16 bundles of para-aramid fibers are bundled into 8 bundles of para-aramid filament bundles after passing through the second-level bundling-drying device 22, and then the 8 bundles of para-aramid fibers are bundled into 2 bundles of para-aramid filament bundles after passing through the third-level bundling-drying device 23, and finally the four-level bundling-drying device 24 is used to bundle the two bundles of para-aramid fibers into one para-aramid silk ribbon, and finally the silk ribbon is stacked in the silk box 32 through the silk collecting device 3.

[0062] It should be noted that this embodiment only illustrates a method for bundling 48 para-aramid filaments into one ribbon. Those skilled in the art can also, based on the inspiration given by this embodiment, bundle 72, 96, etc. bundles of filaments by bundling multiple filaments or bundles into one bundle each time, thereby bundling multiple para-aramid fiber filaments into one para-aramid ribbon.

[0063] In this embodiment, there is no need to directly bundle and dry the spinning device. The bundled ribbons are directly sent to the collecting device. There is no need to set up a para-aramid fiber collecting roller. Spinning and bundling can be carried out simultaneously. The production speed can reach 500-800m / min, which greatly improves the efficiency.

[0064] As a more preferred embodiment of the bundling-drying device in the above embodiment, please refer to Figure 2-Figure 3 , the bundling-drying device comprises:

[0065] The bundling device 201 comprises two sets of bundling wheels 2011 arranged in parallel in front and back, and a bundling hole 2012 arranged between the two sets of bundling wheels 2011.

[0066] The drying device 202 is arranged behind the bundling device 201, and includes a plurality of winding rollers 2022 arranged in a box body 2021, and a steam drying device 2023 is arranged in the box body.

[0067] Specifically, the bundling device 201 includes two sets of bundling wheels 2011 arranged in parallel in front and back, and a bundling hole 2012 arranged between the two sets of bundling wheels 2011. The bundles are bundled under the action of the bundling wheels 2011. A plurality of winding rollers 2022 are arranged in the drying device 202, such as Figure 3As shown in the figure, the silk ribbon passes through six winding wheels 2022 in the drying device 202. The winding wheels 2022 can increase the travel length of the silk bundle in the drying device 202, which is beneficial to improving the drying efficiency of the silk bundle. In addition, in order to achieve parallel silk bundles from the bundling device 201 to the drying device 202 and limit the silk bundles, an upper wire entry limiting wheel 2025 and a lower wire entry limiting wheel 2024 are provided at the silk bundle entrance of the box 2021.

[0068] Please refer to Figure 4 Based on the above embodiment, as a preferred embodiment of the wire feeding device 31, the wire feeding device 31 includes a wire guide roller 311, and two wire feeding rollers 312 moving toward each other below the wire guide roller 311, wherein the two wire feeding rollers 312 are tangent to the fed ribbon. The ribbon is introduced between the two wire feeding rollers 312 through the wire guide roller 311, and the wire feeding rollers 312 are tangent to the fed ribbon, so that the bundled ribbon is continuously fed into the silk box 32.

[0069] Please refer to Figure 4 , further, the wire feeding device comprises:

[0070] A first limiting wheel 341 and a second limiting wheel 342, wherein the first limiting wheel 341 and the second limiting wheel 342 are staggered and arranged directly above and below the path through which the ribbon passes, so as to limit the ribbon between the first limiting wheel 341 and the second limiting wheel 342;

[0071] The guide roller 31 is arranged behind the first limiting wheel 341 and the second limiting wheel 342, and is used to drive the ribbon to move and convey the ribbon to the wire feeding roller 32;

[0072] The wire feeding roller 32 includes two wire feeding rollers 32 that move toward each other and are arranged below the wire guide roller 31. Both of the wire feeding rollers 32 are tangent to the fed silk ribbon.

[0073] More specifically, a ribbon outlet 33 is provided vertically downwardly from the tangent surface of the two wire feeding rollers.

[0074] The wire guide roller 31 and the two wire feeding rollers 32 described in the present embodiment are both rotatable mechanisms, and the power source is a motor, which can be specifically a servo motor. The power connection method between the motor and the wire guide roller 31 and the two wire feeding rollers 32 can be that the motor output shaft is connected to the rotating shaft of the wire guide roller 31 and the two wire feeding rollers 32 through one of the transmission devices such as couplings, gears, belts, chains, etc., and the specific structure does not need to be described one by one.

[0075] During the specific implementation process, a bundled para-aramid ribbon is limited by the first limiting wheel 341 and the second limiting wheel 342, so that the ribbon is level from the discharge port of the drying device 202 to the guide roller 31. After passing through the first limiting wheel 341 and the second limiting wheel 342, the para-aramid ribbon passes through the guide roller 31. Under the guidance and drive of the guide roller 31, the para-aramid ribbon enters between the two wire feeding rollers 32, so that the two wire feeding rollers 32 are tangent to the fed ribbon. Under the action of the two wire feeding rollers 32 moving in opposite directions, the ribbon continues to enter the wire box 32 through the discharge port 33.

[0076] Please refer to Figure 5 On the basis of the above-mentioned embodiment, as a preferred embodiment of the wire collecting device, the wire collecting device also includes a wire collecting reciprocating device 35 for driving the wire collecting box 32 to reciprocate, and the wire collecting reciprocating device 35 includes a left-right moving device 351 and a front-back moving device 352, and the left-right moving device 351 and the front-back moving device 352 are independently installed up and down.

[0077] Specifically, the left-right moving device 351 is a pulley moving device, which specifically includes a placing plate 3511 and a plurality of sliding wheels 3512 arranged below the placing plate 3511. The placing plate 3511 moves back and forth left and right under the action of the sliding wheels 3512. The front-back moving device 352 is a track roller moving device, which specifically includes a transverse track 3521 and a roller 3522 arranged in cooperation with the transverse track 3521. The power of the roller 3522 comes from a driving motor 3523. The left-right moving device 351 is located above the front-back moving device 352.

[0078] In an optional embodiment, the wire reciprocating device can be arranged as follows: Figure 6 The moving mode is reciprocating movement. The arrows in the figure represent the order of the ribbon falling positions during the movement of the silk reciprocating device. It should be noted that the figure only illustrates the order and direction of the ribbon falling positions, and does not represent the intervals of the ribbon falling positions. In the actual implementation process, the ribbons should be densely arranged.

[0079] Please refer to Figure 7 On the basis of the above embodiment, a pressure plate assembly 36 that can move up and down is arranged above the wire box 32. Specifically, the pressure plate assembly 36 includes a pressure plate 361, a lifting device 362, and a bracket 363. The pressure plate 361 is connected to the bracket 363 through the lifting device 362. In an optional implementation, the lifting device 362 is a screw lifting device, and the driving force of the lifting device is a servo motor.

[0080] The lifting device 362 includes a lifting motor 3624 arranged on a bracket 363, a screw 3623 connected to the output shaft of the lifting motor 3624, a screw rod 3621 arranged in cooperation with the screw rod 3623, and a slide bar 3622 for limiting the position of the screw rod 3621. The lower ends of the slide bar 3622 and the screw rod 3621 are connected to the pressing plate 361. The position of the bracket 363 is movable. Figure 7 The moving mode of the bracket 363 is not shown in the figure, but those skilled in the art can set a moving device such as a pulley, a slide rod, etc. on the bottom plate of the bracket 363.

[0081] During the specific implementation process, when the position of the silk box 32 is moved to make the vertical downward projection position of the pressure plate assembly 36 coincide with the vertical downward projection position of the side of the silk box 32 close to the pressure plate, the pressure plate 361 is lowered by the lifting device 362, so that the pressure plate 361 squeezes the stacked silk ribbons, thereby solving the problem that the fiber silk ribbons are not stacked tightly but loosely in the silk box, resulting in knots inside the fiber silk ribbon box.

[0082] In order to compact or compact the silk strips in the silk box, at least one side edge of the silk box is provided with the pressing plate assembly, such as the left side, the right side, the front side, and the rear side.

[0083] Another embodiment is a tow collection method for preparing aramid staple fibers, which sequentially includes the steps of dissolving PPTA with concentrated sulfuric acid, degassing, filtering, spinning, washing, bundling, drying, and collecting. The bundling, drying, and collecting steps are:

[0084] S1. Bundling and drying: Bundling n aramid fiber bundles into one ribbon bundle, specifically,

[0085] S11, performing multi-stage bundling and drying on the washed a aramid yarn to form a yarn bundle, wherein the number of bundling-drying devices in the first stage is multiple times the number of bundling-drying devices in the second stage.

[0086] S12, performing multi-stage bundling and drying in step S11 to obtain a para-aramid ribbon, wherein the moisture content of the obtained para-aramid ribbon is 10% to 20%.

[0087] S2. Silk collection: When the bundled silk ribbons are fed into the silk box through the wire feeding device, the silk ribbons are stacked in the silk box under the action of gravity and the force of the reciprocating motion of the silk box.

[0088] As a preferred technical solution of step S1 of the tow collection method for preparing aramid staple fibers in the present application, the first drying process has a drying steam pressure of 0.5 MPa and a drying temperature of 120-140° C.; the second drying process has a drying steam pressure of 1 MPa and a drying temperature of 80-100° C. The water content is controlled at 10%-20%, the electrostatic effect of fibers with high water content is reduced, and oiling agent is not required to reduce the electrostatic effect of fibers, and fibers with high water content have good bundling properties.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A tow collection system for preparing para-aramid staple fibers, comprising: PPTA and concentrated sulfuric acid dissolving device, degassing device, filtering device, spinning device, water washing device (1), bundling-drying device (2), and wire collecting device (3); The wire collecting device (3) comprises a wire feeding device (31) and a wire storage box (32), wherein the wire storage box (32) is arranged below a discharge port (33) of the wire feeding device (31), and the wire storage box (32) performs forward, backward, left and right reciprocating motion relative to the discharge port (33) of the wire feeding device (31); The bundling-drying device (2) is: a multi-stage bundling-drying device (2) arranged in series along the moving direction of the filament bundle; In the multi-stage bundling-drying device (2), the number of the bundling-drying devices in the previous stage is multiple times the number of the bundling-drying devices in the next stage; The bundling-drying device (2) comprises: Clustering device (201); A drying device (202), the drying device (202) being arranged behind the bundling device (201), comprising a plurality of wire winding rollers (2022) arranged in a box (2021), wherein a steam drying device (2023) is arranged in the box (2021).

2. The tow collection system for preparing para-aramid staple fibers according to claim 1, characterized in that: The wire feeding device (31) comprises a wire guide roller (311), two wire feeding rollers (312) moving towards each other below the wire guide roller (311), Wherein, the two wire feeding rollers (312) are both tangent to the fed silk ribbon.

3. The tow collection system for preparing para-aramid staple fibers according to claim 1, characterized in that: The wire collecting device (3) further comprises a wire collecting reciprocating device (35) for driving the wire collecting box (32) to reciprocate, the wire collecting reciprocating device (35) comprising a left-right moving device (351) and a front-back moving device (352), the left-right moving device (351) and the front-back moving device (352) being independently installed at the upper and lower parts.

4. The tow collection system for preparing para-aramid staple fibers according to claim 1, characterized in that: A pressing plate assembly (36) is arranged above the silk collecting box (32) and is movable up and down in the silk collecting box.

5. The tow collection system for preparing para-aramid staple fibers according to claim 4, characterized in that: The pressing plate assembly (36) is provided on at least one side edge of the silk receiving box (32).

6. A tow collection method for preparing aramid staple fibers, comprising the steps of dissolving PPTA with concentrated sulfuric acid, degassing, filtering, spinning, washing, bundling, drying, and collecting, characterized in that: The bundling, drying and silk collecting steps are as follows: S1. Bundling and drying: Bundling n aramid fiber bundles into one ribbon bundle, specifically, S11, performing multi-stage bundling and drying on the washed aramid yarn a tow, wherein the number of bundling-drying devices in the first stage is multiple times the number of bundling-drying devices in the second stage; S12, performing multi-stage bundling and drying in step S11 to obtain a para-aramid ribbon, wherein the moisture content of the obtained para-aramid ribbon is 10% to 20%; S2. Silk collection: When the bundled silk ribbons are fed into the silk box through the wire feeding device, the silk ribbons are stacked in the silk box under the action of gravity and the force of the reciprocating motion of the silk box.

7. The tow collecting method for preparing aramid staple fibers according to claim 6, characterized in that: In the first stage drying process of step S11, the drying steam pressure is 0.5 MPa and the drying temperature is 120-140°C; in the second stage drying process, the drying steam pressure is 1 MPa and the drying temperature is 80-100°C.

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