Large-tow polyimide fiber dry spinning tunnel and spinning method

Abstract

This invention discloses a dry spinning tunnel and spinning method for large-tow polyimide fibers. The spinning tunnel includes a tunnel body, an air inlet pipe, two first perforated plates, two second perforated plates, and two annular spinnerets. The tunnel body is divided into an upper tunnel, a middle tunnel, and a lower tunnel from top to bottom, which are connected sequentially. The top of the upper tunnel and the bottom of the lower tunnel are both closed. The bottom of the lower tunnel has a filament outlet. The polyimide solution is ejected from the annular spinneret located at the top of the upper tunnel to form a liquid stream. Hot air from the air inlet pipe is blown evenly onto the liquid stream through the first perforated plates. The heating and insulation layers of the upper, middle, and lower tunnels can be adjusted to the corresponding temperatures according to process requirements, which allows the solvent in the large-tow liquid stream to evaporate in time and the filaments to solidify rapidly, thereby reducing filament tangling and achieving spinnability and stability of the large-tow fibers. The production of large tows of polyimide fibers produced by dry spinning of the present invention can be increased by at least 15 times.

Description

Technical Field

[0001] The invention relates to the technical field of polyimide fiber spinning, in particular to a large-tow polyimide fiber dry spinning tunnel and a spinning method. Background Art

[0002] In the large-tow polyimide fiber dry spinning process technology, the spinning shaft is a very important equipment. The current spinning shaft has a low spinning output. Due to structural limitations, one shaft position can only spin a 168-hole tow. In the spinning process of polyimide, the polyimide spinning stock solution enters the spinning shaft through the spinneret, and heated gas is blown into the shaft at the same time, and the solvent will flash. However, for large-tow spinning, traditional spinning shafts generally use cross-flow blowing, which causes uneven wind receiving surfaces of large tows, making it impossible to evaporate the solvent in time, making it impossible to produce large tows, and easily forming problems such as parallel yarns. Summary of the invention

[0003] The object of the present invention is to provide a large-tow polyimide fiber dry spinning tunnel and spinning method in view of the above-mentioned deficiencies in the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] The large-tow polyimide fiber dry spinning tunnel of the present invention comprises a tunnel body, an air inlet pipe, two first orifice plates, two second orifice plates and two annular spinnerets;

[0006] The corridor body is divided into an upper corridor, a middle corridor and a lower corridor from top to bottom. The upper corridor, the middle corridor and the lower corridor are connected in sequence. The top end of the upper corridor and the bottom end of the lower corridor are both closed, and the bottom end of the lower corridor is provided with a wire outlet.

[0007] One end of the air inlet pipe is inserted into the upper tunnel, and the end is closed; openings are respectively provided on the two side walls of the air inlet pipe, two first orifice plates are respectively provided at the openings, two second orifice plates are provided in the upper tunnel, and are located on both sides of the air inlet pipe, the second orifice plates and the first orifice plates located on the same side are arranged at intervals to form a spinning channel, and two annular spinnerets are provided at the top of the upper tunnel, and are located on both sides of the air inlet pipe, and correspond to the spinning channel;

[0008] The two second orifice plates are spaced apart from the inner walls on both sides of the upper corridor and form two return air passages. The top side wall of the middle corridor is provided with a first return air outlet connected to the return air passage.

[0009] The diameter of the lower corridor is larger than that of the middle corridor, a shoulder is formed at the connection between the lower corridor and the middle corridor, two air inlets are arranged on the shoulder, the two air inlets are symmetrical about the central axis of the lower corridor, and a second return air outlet is arranged on the bottom side wall of the lower corridor;

[0010] A heating and heat-insulating layer is arranged on the outer wall of the tunnel body.

[0011] Furthermore, the number of spinning holes of the annular spinneret is 3000-5000 holes.

[0012] Furthermore, the heating and thermal insulation layer includes an electric heating layer and a thermal insulation layer, and the thermal insulation layer is arranged on the outer surface of the electric heating layer.

[0013] Furthermore, the diameters of the upper corridor and the middle corridor are 500-550 m, and the diameter of the lower corridor is 1000-1100 m.

[0014] Furthermore, the height of the upper corridor is 1.5~3m, the height of the middle corridor is 2~3m, and the height of the lower corridor is 10~15m.

[0015] Furthermore, the upper corridor and the lower corridor are both connected to a gas heating device, the upper corridor is connected to the gas heating device through the air inlet pipe, and the lower corridor is connected to the gas heating device through the air inlet.

[0016] Furthermore, the first return air outlet and the second return air outlet are both connected to a solvent recovery device.

[0017] The second object of the present invention is to provide a method for spinning large tows of polyimide fibers, using the large tow polyimide fiber dry spinning tunnel mentioned above for spinning.

[0018] Furthermore, the air volume of the air inlet pipe is 1-3m 3 / min, the air volume at the lower air inlet is: 8-10 m 3 / min.

[0019] Furthermore, the air inlet temperature of the air inlet pipe is 350~450℃, the electric heating temperature of the upper corridor is 350~450℃, the electric heating temperature of the middle corridor is 300~400℃, the air inlet temperature of the lower corridor is 200~300℃, and the electric heating temperature of the lower corridor is 200~300℃.

[0020] The beneficial effects brought by the technical solution provided by the present invention are:

[0021] The large-tow polyimide fiber dry spinning tunnel provided by the present invention comprises a tunnel body, an air inlet pipe, two first orifice plates, two second orifice plates and two annular spinnerets. The tunnel body is divided into an upper tunnel, a middle tunnel and a lower tunnel from top to bottom. A built-in air inlet pipe is used in the upper tunnel to evenly blow the air to the filament bundle through the first orifice plate. At the same time, the heating and heat-insulating layer of the upper tunnel can adjust the corresponding temperature according to the process requirements to achieve rapid evaporation of the solvent and make the fiber initially solidified. The return air channel makes the hot air flow field stable, and the airflow blowing to the filament bundle is uniform and stable, so that the solvent in the thin flow of the large-tow stock solution can be evaporated in time, and the filaments can be quickly solidified. Solidification, thereby reducing the paralleling between the tows, achieving the spinnability and stability of the large tows; the heating and insulation layer of the middle channel can further increase the temperature to further evaporate the residual solvent; the diameter of the lower channel is increased to 1-1.5 times that of the middle channel, so that the concentration of the generated solvent is reduced after entering the lower channel, which is convenient for the solvent of the tow to evaporate completely. The lower channel also adopts a heating and insulation layer, and the process temperature can be freely adjusted to completely evaporate the solvent in the tow. The air inlet and the second return air outlet added to the lower channel are to take the solvent generated by the middle channel and the lower channel out of the channel in time to achieve the solidification of the large tow fibers. The large tow production of the polyimide fiber dry spinning of the present invention can increase the output by at least 15 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a schematic diagram of the structure of a large-tow polyimide fiber dry spinning tunnel.

[0023] 1. Corridor body; 11. Upper corridor; 12. Middle corridor; 13. Lower corridor; 131. Wire outlet; 132. Air inlet; 133. Second return air outlet; 2. Air inlet pipe; 21. Opening; 3. First orifice plate; 4. Second orifice plate; 5. Annular spinneret; 6. Spinning channel; 7. Return air channel; 71. First return air outlet; 8. Heating and thermal insulation layer; 81. Electric heating layer; 82. Thermal insulation layer. DETAILED DESCRIPTION

[0024] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments.

[0025] Example 1

[0026] like Figure 1As shown, a large-tow polyimide fiber dry spinning corridor provided by the present invention includes a corridor body 1, an air inlet pipe 2, two first orifice plates 3, two second orifice plates 4 and two annular spinnerets 5; the corridor body 1 is divided into an upper corridor 11, a middle corridor 12 and a lower corridor 13 from top to bottom, the upper corridor 11, the middle corridor 12 and the lower corridor 13 are connected in sequence, the top end of the upper corridor 11 and the bottom end of the lower corridor 13 are both closed, and the bottom end of the lower corridor 13 is provided with a wire outlet 131; one end of the air inlet pipe 2 is inserted into the upper corridor 11, and the end is closed; openings 21 are respectively provided on the two side walls of the air inlet pipe 2, the two first orifice plates 3 are respectively arranged at the openings 21, the two second orifice plates 4 are arranged in the upper corridor 11, and are located on both sides of the air inlet pipe, and are located on the same side. The second orifice plate and the first orifice plate are arranged at intervals to form a spinning channel 6. Two annular spinnerets 5 are arranged at the top of the upper corridor 11 and are located on both sides of the air inlet pipe 2, and correspond to the spinning channels 6; the two second orifice plates 4 are arranged at intervals with the inner walls on both sides of the upper corridor 11 and form two return air channels 7, and the top side wall of the middle corridor 12 is provided with a first return air outlet 71 connected to the return air channel 7; the diameter of the lower corridor 13 is larger than that of the middle corridor 12, and a shoulder is formed at the connection between the lower corridor 13 and the middle corridor 12, and two air inlets 132 are provided on the shoulder, and the two air inlets 132 are symmetrical about the central axis of the lower corridor 13, and a second return air outlet 133 is provided on the bottom side wall of the lower corridor 13; a heating and heat preservation layer 8 is provided on the outer wall of the corridor body 1.

[0027] Compared with the conventional spinning tunnel of large-tow polyimide fiber, the spinning tunnel provided by the present invention blows uniformly to the filament bundle through the first orifice plate 3, and at the same time, the heating and heat-insulating layer of the upper tunnel 11 can adjust the corresponding temperature according to the process requirements to achieve rapid evaporation of the solvent and preliminary solidification of the fiber. The return air channel 7 makes the hot air flow field stable, and the air flow blowing to the filament bundle is uniform and stable, so that the solvent in the thin flow of the large-tow stock solution can be evaporated in time, and the filaments are quickly solidified, thereby reducing the paralleling between the filament bundles and achieving the spinnability and stability of the large filament bundle; while the middle tunnel The heating and insulation layer 12 can further increase the temperature to further evaporate the residual solvent; the diameter of the lower channel 13 is increased to 1-1.5 times that of the middle channel 12, so that the concentration of the generated solvent is reduced after entering the lower channel, which is convenient for the solvent in the filament bundle to evaporate completely. The lower channel 13 also adopts a heating and insulation layer 8, and the process temperature can be freely adjusted to completely evaporate the solvent in the filament bundle. The additional air inlet and the second return air outlet of the lower channel are to bring the solvent generated by the middle channel 12 and the lower channel 13 out of the channel in time to achieve the solidification of large filament bundle fibers.

[0028] In some embodiments, in order to improve the yield and spinning quality, the number of spinning holes of the annular spinneret 5 may be 3000-5000 holes.

[0029] In some embodiments, in order to achieve uniform heating and rapid solidification of the polyimide fiber filaments, thereby reducing the possibility of twisting between the filaments, the heating and thermal insulation layer 8 may include an electric heating layer 81 and a thermal insulation layer 82, and the thermal insulation layer 82 is arranged on the outer surface of the electric heating layer 81.

[0030] In some embodiments, in order to make the airflow in the spinning channel stable and reduce the shaking of the filaments, the diameters of the upper channel 11 and the middle channel 12 may be 500-550 m, and the diameter of the lower channel 11 may be 1000-1100 m.

[0031] In some embodiments, in order to improve the spinning quality, the solvent is excluded from the spinning tunnel, the height of the upper tunnel 11 can be 1.5-3 m, the height of the middle tunnel can be 2-3 m, and the height of the lower tunnel can be 10-15 m.

[0032] In some embodiments, in order to ensure that the air flow in the spinning tunnel is evenly heated to meet the temperature requirements of each spinning process section, the upper tunnel 11 and the lower tunnel 13 are both connected to a gas heating device, the upper tunnel 11 is connected to the gas heating device through the air inlet pipe 2, and the lower tunnel 13 is connected to the gas heating device through the air inlet 132.

[0033] In some embodiments, in order to reduce production costs for economical and environmental protection, the first return air outlet 71 and the second return air outlet 133 are both connected to a solvent recovery device, and the recovered solvent can be reused after processing.

[0034] When the large-tow polyimide fiber dry spinning tunnel of the present invention is in operation, the polyimide solution is ejected from the annular spinneret 5 located at the top of the upper tunnel 11 to form a stock solution stream, which passes through the upper tunnel 11, the middle tunnel 12 and the lower tunnel 13 in sequence. In the process of the stock solution stream passing through the tunnel body 1, the solvent (DMAC) of the polyimide gradually evaporates under the action of the medium and high temperature airflow in the tunnel body 1. The stock solution stream gradually changes from liquid to solid polyimide fiber in the process of passing from the upper tunnel 11 to the middle tunnel 12 and to the lower tunnel. The polyimide fiber becomes a large-tow polyimide fiber after passing through the bottom outlet 131 of the lower tunnel 13.

[0035] The airflow direction of the large-tow polyimide fiber dry spinning tunnel of the present invention is as follows: the spinning tunnel of the present invention has an air inlet pipe 2, two first return air outlets 71, two air inlets 132, and a second return air outlet 133. Hot air enters from the air inlet pipe 2, enters the upper tunnel 11 through the micropores of the first orifice plate 3 on the side wall of the air inlet pipe 2, blows toward the filament bundle, enters the return air channel 7 through the second orifice plate 4 on the inner wall of the upper tunnel 11, and then goes out from the two first return air outlets 71. The remaining air volume enters the lower tunnel 13 through the middle tunnel 12. At the same time, hot air enters the lower tunnel 13 from the two air inlets 132 and is drawn out of the tunnel through the second return air outlet 133.

[0036] Example 2

[0037] This embodiment relates to a large-tow polyimide fiber spinning method, which uses the large-tow polyimide fiber dry spinning tunnel of embodiment 1 to spin the fibers.

[0038] First, start the gas heating device and the air supply device to heat the air to 350~450℃℃. The heated air enters the upper tunnel 11 through the air inlet pipe 2. The air volume of the air inlet pipe is 1-3m 3 / min, the hot air in the air inlet pipe 2 flows horizontally through the first perforated plate 3 to the spinning channel 6, flows through the second perforated plate 4 to the return air channel 7, and at the same time, it is sent to the lower channel 13 through two air inlets 132, with an air volume of 8-10 m 3 / min.

[0039] The tunnel body is preheated, the temperature in the upper tunnel is 350-450°C, the temperature in the middle tunnel is 300-400°C, and the temperature in the lower tunnel is 200-300°C. After completion, a thin stream of stock solution is sprayed out from the annular spinneret 5 arranged at the top of the upper tunnel 11. The solid content of the stock solution is 28%, and the flow rate of the annular spinneret is 50cm 3 / min, the stock solution thin stream passes through the upper tunnel 11, the middle tunnel 12 and the lower tunnel 13. Under the action of the hot air in the tunnel, the solvent in the stock solution thin stream is taken away by the hot air, and the spandex yarn and polyimide yarn bundle that are transformed from liquid to solid leave the tunnel body from the bottom outlet 131 of the lower tunnel 13. At the same time, the hot air with solvent recovered from the first return air outlet 71 and the second return air outlet 133 flows to the solvent recovery device, which recovers the solvent and reuses it.

[0040] For matters not mentioned above, the prior art applies.

[0041] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art to which the present invention belongs may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but they will not deviate from the direction of the present invention or exceed the scope defined by the attached claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A large-tow polyimide fiber dry spinning tunnel, characterized in that: It comprises a channel body (1), an air inlet pipe (2), two first orifice plates (3), two second orifice plates (4) and two annular spinnerets (5); The corridor body (1) is divided into an upper corridor (11), a middle corridor (12) and a lower corridor (13) from top to bottom. The upper corridor (11), the middle corridor (12) and the lower corridor (13) are connected in sequence. The top end of the upper corridor (11) and the bottom end of the lower corridor (13) are both closed, and the bottom end of the lower corridor (13) is provided with a wire outlet (131); the diameters of the upper corridor (11) and the middle corridor (12) are 500-550 μm, and the diameter of the lower corridor (13) is 1000-1100 μm; the height of the upper corridor (11) is 1.5-2.0mm. The height of the middle passage (12) is 1.5-3 m, the height of the middle passage (12) is 2-3 m, and the height of the lower passage (13) is 10-15 m; the heating and heat-insulating layer of the middle passage (12) can further increase the temperature so that the residual solvent can be further evaporated; the diameter of the lower passage (13) is increased to 1-1.5 times that of the middle passage (12), so that the concentration of the generated solvent is reduced after entering the lower passage (13), which facilitates the complete evaporation of the solvent in the filament bundle; the heating and heat-insulating layer provided in the lower passage (13) can freely adjust the process temperature to completely evaporate the solvent in the filament bundle; One end of the air inlet pipe (2) is inserted into the upper tunnel (11), and the end is closed; openings (21) are respectively provided on the two side walls of the air inlet pipe (2); two first orifice plates (3) are respectively provided at the openings (21); two second orifice plates (4) are provided in the upper tunnel (11) and are located on both sides of the air inlet pipe; the second orifice plates and the first orifice plates located on the same side are arranged at intervals to form a spinning channel (6); two annular spinnerets (5) are provided at the top of the upper tunnel (11), and are located on both sides of the air inlet pipe (2), and correspond to the spinning channel (6); The two second orifice plates (4) are spaced apart from each other on the inner walls of both sides of the upper corridor (11) to form two return air passages (7); a first return air outlet (71) connected to the return air passage (7) is provided on the top side wall of the middle corridor (12); The diameter of the lower corridor 13 is larger than that of the middle corridor (12); a shoulder is formed at the connection between the lower corridor (13) and the middle corridor (12); two air inlets (132) are provided on the shoulder; the two air inlets (132) are symmetrical about the central axis of the lower corridor (13); and a second return air outlet (133) is provided on the bottom side wall of the lower corridor (13); A heating and heat-insulating layer (8) is provided on the outer wall of the tunnel body (1).

2. A large-tow polyimide fiber dry spinning tunnel as claimed in claim 1, characterized in that: The number of spinning holes of the annular spinneret (5) is 3000-5000 holes.

3. A large-tow polyimide fiber dry spinning tunnel as claimed in claim 2, characterized in that: The heating and thermal insulation layer (8) comprises an electric heating layer (81) and a thermal insulation layer (82), wherein the thermal insulation layer (82) is arranged on the outer surface of the electric heating layer (81).

4. A large-tow polyimide fiber dry spinning tunnel as claimed in claim 3, characterized in that: The upper corridor (11) and the lower corridor (13) are both connected to a gas heating device; the upper corridor (11) is connected to the gas heating device via the air inlet pipe (2), and the lower corridor (13) is connected to the gas heating device via the air inlet port (132).

5. A large-tow polyimide fiber dry spinning tunnel as claimed in claim 3, characterized in that: The first return air outlet (71) and the second return air outlet (133) are both connected to a solvent recovery device.

6. A method for spinning a large tow of polyimide fibers, characterized in that: The spinning is carried out using the large-tow polyimide fiber dry spinning tunnel as described in any one of claims 1 to 5.

7. The spinning method according to claim 6, characterized in that The air volume of the air inlet pipe is 1~3m 3 / min, the air volume of the air inlet of the lower corridor is: 8~10 m 3 / min.

8. The spinning method according to claim 6, characterized in that The air inlet temperature of the air inlet pipe is 350~450℃, the electric heating temperature of the upper corridor is 350~450℃, the electric heating temperature of the middle corridor is 300~400℃, the air inlet temperature of the lower corridor is 200~300℃, and the electric heating temperature of the lower corridor is 200~300℃.

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