Carbon fiber precursor spinneret assembly and method for preparing carbon fiber precursor by dry-jet wet spinning

Abstract

The present invention provides a carbon fiber spinneret assembly and a method for preparing carbon fiber precursor filaments by dry-jet wet spinning, belonging to the field of carbon fiber preparation. The carbon fiber spinneret assembly includes a spinneret plate and a liquid supply pipe. The first end of the liquid supply pipe is communicated with the spinneret plate, and the second end of the liquid supply pipe is communicated with a spinning dope filtration and supply component. A cutting structure is provided in the supply pipe. When the spinning dope is pumped into the liquid supply pipe, the spinning dope can be cut into at least two independent parts in the radial direction of the liquid supply pipe by the cutting structure. The present invention can cut the spinning dope flowing into the liquid supply pipe, enable the spinning dope to flow interactively during the pumping process, improve the uniformity of the viscosity of the spinning dope, slow down the pressure fluctuation of the spinneret at the moment of spinning, avoid activating the protection function of the bursting disc of the spinneret assembly, prevent the leakage of the dope and the bulging and deformation of the spinneret plate, and can also avoid defects such as blockage of the spinneret plate with material blocks, excessive broken ends, and large deviation of the CV value during the spinning process, improving the performance indexes of the precursor filaments and the stability of production operation.

Description

Technical Field

[0001] The invention belongs to the field of carbon fiber processing, and in particular relates to a carbon fiber precursor spinning assembly and a method for preparing carbon fiber precursor by dry-jet wet spinning. Background Art

[0002] Polyacrylonitrile-based carbon fiber has the advantages of high tensile strength, high tensile modulus, low density, and chemical corrosion resistance. It is widely used in aerospace, wind turbine blades, building reinforcement and other fields. Compared with traditional wet spinning, the biggest advantage of dry-jet wet spinning is that it can achieve a high yarn collection speed (300~500m / min), which can greatly improve production efficiency and reduce production costs. Therefore, carbon fiber prepared by dry-jet wet spinning has been widely used in the above fields.

[0003] In the spinning process, the spinning pressure is directly affected by the amount of spinning solution discharged and the viscosity of the spinning solution. The greater the amount of spinning solution discharged, the higher the viscosity and the higher the spinning pressure. Since the dry-jet wet spinning has a fast spinning speed and the spinning solution has a high solid content and high viscosity, the spinning pressure is relatively high in the dry-jet wet spinning process.

[0004] When the spinning solution is extruded through the spinneret to form a thin stream of the solution, the instantaneous spinning pressure is very high due to the viscoelastic energy storage caused by the convergence of the streamlines, which can easily trigger the protective function of the bursting piece of the spinneret assembly to cause the spinning solution to leak, resulting in the spinneret being unable to continue to be used or causing the spinneret to be locally overstressed and bulge and deform. Therefore, under the premise of ensuring the surface state of the spinneret, the spinning pressure at the moment of spinning should be reduced. On the other hand, the uniformity of the viscosity of the spinning solution should also be improved to reduce the fluctuation of the spinning pressure at the moment of spinning.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] Therefore, the present invention provides a carbon fiber precursor spinning assembly and a method for preparing carbon fiber precursor by dry-jet wet spinning, which can solve the technical problems in the prior art of carbon fiber dry-jet wet spinning process, that is, the insufficient viscosity uniformity of the spinning solution leads to excessive fluctuations in the spinning pressure, which in turn stimulates the protective function of the bursting piece of the spinning assembly to cause leakage of the spinning solution, bulging and deformation of the spinneret, and the like, which makes it impossible to continue to use the spinneret.

[0007] In order to solve the above problems, the present invention provides a carbon fiber precursor spinning assembly, including a spinneret and a liquid supply tube, wherein the first end of the liquid supply tube is connected to the spinneret, and the second end of the liquid supply tube is connected to a spinning solution filtering supply component, and the liquid supply tube has a cutting structure. When the spinning solution is pumped into the liquid supply tube, the spinning solution can be cut by the cutting structure into at least two independent parts in the radial direction of the liquid supply tube.

[0008] In some embodiments, the cutting structure includes a plurality of cutting blades arranged in sequence along the axial direction of the liquid supply pipe.

[0009] In some embodiments, the cutting blade is formed by twisting a rectangular metal thin plate by a preset angle, and the preset angle is greater than 0°.

[0010] In some embodiments, the number of the cutting blades is 6 to 30, and / or the preset angle is 180°.

[0011] In some embodiments, the length of the cutting blade in the axial direction of the liquid supply pipe is L, the twisting diameter of the cutting blade is D, and L / D is 1.0 to 2.0.

[0012] In some embodiments, the twisting directions of two adjacent cutting blades are opposite, and in the flow direction of the spinning dope, the cutting blade in the upstream is the upstream cutting blade, and the cutting blade in the downstream is the downstream cutting blade. The edge of the upstream cutting blade facing the downstream cutting blade and the edge of the downstream cutting blade facing the upstream cutting blade form an intersection.

[0013] In some embodiments, the cutting structure is detachably assembled in the liquid supply pipe.

[0014] In some embodiments, a temperature control unit is disposed around the outer circumferential side of the wall of the liquid supply pipe, and the flow direction of the temperature control medium in the temperature control unit is opposite to the flow direction of the spinning dope in the liquid supply pipe.

[0015] The present invention also provides a method for preparing carbon fiber precursor by dry-jet wet spinning, which is performed by using the above carbon fiber precursor spinning assembly, and includes the following steps:

[0016] Spinning step: Start the dope pumping device to pump the spinning dope to eject from the spinneret at an initial spinning speed, and stepwise increase the spinning speed to the spinning speed after the initial spinning speed is stable.

[0017] Solidification step: The spinning dope forms a spinning dope stream under the action of the spinneret, and the spinning dope stream enters the coagulation bath through the air layer and solidifies to form a nascent fiber.

[0018] Spinning step: Wash, hot water draw, oil, dry and densify, and steam draw the nascent fiber to obtain polyacrylonitrile carbon fiber precursor.

[0019] In some embodiments, the initial spinning speed is 0.5 to 0.7 times of the spinning speed; and / or the adjustment range of stepwise increasing the spinning speed is 1.5 to 3.0 m / min.

[0020] The present invention provides a spinneret assembly for carbon fiber precursor and a method for preparing carbon fiber precursor by dry-jet wet spinning. By providing a cutting structure in the liquid supply pipe, the spinning dope flowing into the liquid supply pipe can be cut, so that the spinning dope can flow alternately during the pumping process, reducing the fluctuation degree of the viscosity of the spinning dope. In this way, the pressure fluctuation during the spinning instant can be slowed down, the protection function of the bursting disc of the spinneret assembly can be avoided from being activated, the leakage of the dope and the bulging and deformation of the spinneret plate can be prevented, and at the same time, the defects such as blockage of the spinneret plate with material, excessive broken ends, and large deviation of the CV value during the spinning process can be avoided, improving the performance indexes of the precursor and the stability of production operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a schematic diagram of a dry-jet wet spinning production system for carbon fiber precursor where the spinneret assembly of the carbon fiber precursor according to an embodiment of the present invention is located;

[0022] Figure 2 is Figure 1 a three-dimensional schematic diagram of the cutting structure in the spinneret assembly of the carbon fiber precursor in, and the arrow in the figure shows the flow direction of the spinning dope;

[0023] Figure 3 FIG. is a graph showing the change trend of the spinning pressure with time when the spinning speed is gradually increased to the spinning speed in the method for preparing carbon fiber precursor by dry-jet wet spinning according to another embodiment of the present invention.

[0024] The reference numerals are shown as:

[0025] 1, spinneret plate; 12, liquid supply pipe; 2, cutting structure; 21, cutting blade; 3, temperature control unit; 4, coagulation bath. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Referring to Figures 1 to 3 shown in, according to an embodiment of the present invention, a spinneret assembly for carbon fiber precursor is provided, including a spinneret plate 1 and a liquid supply pipe 12. The first end of the liquid supply pipe 12 is communicated with the spinneret plate 1, and the second end of the liquid supply pipe 12 is communicated with a spinning dope filtration and supply component (including a pumping device, not shown in the figure). A cutting structure 2 is provided in the liquid supply pipe 12. When the spinning dope is pumped into the liquid supply pipe 12, the spinning dope can be cut by the cutting structure 2 into at least two parts independent in the radial direction of the liquid supply pipe 12. In this technical solution, by providing the cutting structure 2 in the liquid supply pipe 12, the spinning dope flowing into the liquid supply pipe 12 can be cut, so that the spinning dope can flow alternately during the pumping process, improving the uniformity of the viscosity of the spinning dope. In this way, the pressure fluctuation during the spinning instant can be slowed down, the protection function of the bursting disc of the spinneret assembly can be avoided from being activated, the leakage of the dope and the bulging and deformation of the spinneret plate can be prevented, and at the same time, the defects such as blockage of the spinneret plate with material, excessive broken ends, and large deviation of the CV value during the spinning process can be avoided, improving the performance indexes of the precursor and the stability of production operation.

[0027] The cutting structure 2 can be realized by using a relatively long cutting blade 21. In a preferred embodiment, the cutting structure 2 includes a plurality of cutting blades 21 arranged in sequence along the axial direction of the liquid supply pipe 12. Combining a plurality of cutting blades 21 to form the cutting structure 2 can reduce the length of each cutting blade 21, so that the number of cutting times can be increased, the cutting efficiency can be improved, and at the same time, it is also convenient for the assembly between the cutting structure 2 and the liquid supply pipe 12. In a preferred embodiment, the cutting structure 2 is detachably assembled in the liquid supply pipe 12, so that the cutting structure 2 can be removed from the liquid supply pipe 12 for maintenance and cleaning after spinning. It can be understood that the inner wall of the liquid supply pipe 12 should have corresponding limiting structures to make the cutting structure 2 in the target position.

[0028] In some embodiments, the cutting blade 21 is formed by twisting a rectangular metal thin plate by a preset angle, and the preset angle is greater than 0°. The cutting blade 21 formed by twisting the metal thin plate forms a certain deflection angle in the flow direction of the spinning dope. In this way, it is beneficial to the interactive flow of the spinning dope during transportation, and can further improve the uniformity of the viscosity of the spinning dope, thereby slowing down the fluctuation of the spinning pressure at the moment of spinning. In a preferred embodiment, the aforementioned preset angle is 180°. By using the cutting blade 21 twisted by 180°, according to the twisting direction, it can be divided into a left-handed cutting unit and a right-handed cutting unit. The cutting units twisted in different directions are connected to each other, so that the spinning dope can be divided into two parts in each stage of the cutting unit and cut step by step, realizing the improvement of the uniformity of the spinning dope.

[0029] In some embodiments, the length of the cutting blade 21 in the axial direction of the liquid supply pipe 12 is L, the twisting diameter of the cutting blade 21 is D, and L / D is 1.0 - 2.0. Specifically, if L / D is too large, the axial length of a single cutting unit is too long, resulting in a reduction in the number of cutting units and the number of cutting times, and a decrease in cutting efficiency under the same length; if L / D is too small, it is easy to increase the processing difficulty of the cutting unit, and at the same time, the residence time of the spinning dope in the cutting unit is too short, resulting in a decrease in cutting efficiency.

[0030] In some embodiments, the twisting directions of two adjacent cutting blades 21 are opposite. In the flow direction of the spinning dope, the cutting blade 21 in the upstream is the upstream cutting blade, and the cutting blade 21 in the downstream is the downstream cutting blade. The edge of the upstream cutting blade facing the downstream cutting blade and the edge of the downstream cutting blade facing the upstream cutting blade form an intersection, that is, they are not parallel. In a preferred embodiment, they are in vertical contact. The number of cutting blades 21 is 6 - 30. Assuming the number is n, at this time, the spinning dope entering the liquid supply pipe 12 will form a cutting number of 2 n units after being cut by the cutting structure 2, and the homogenization purpose of the spinning dope can be achieved by using fewer cutting blades 21.

[0031] The viscosity of the spinning dope is directly affected by temperature. Therefore, a temperature control unit is required to ensure the stability of the viscosity of the spinning dope and avoid unstable pressure during the spinning process. In a specific embodiment, a temperature control unit 3 is disposed around the outer circumferential side of the pipe wall of the liquid supply pipe 12. The flow direction of the temperature control medium in the temperature control unit 3 is opposite to the flow direction of the spinning dope in the liquid supply pipe 12, so as to achieve sufficient heat exchange between the temperature control medium and the spinning dope.

[0032] According to an embodiment of the present invention, there is also provided a method for preparing carbon fiber precursor by dry-jet wet spinning, which is performed by using the above-mentioned carbon fiber precursor spinning component, and includes the following steps:

[0033] Spinning step: Start the dope pumping device to pump the spinning dope and eject it from the spinneret 1 at an initial spinning speed. After the initial spinning speed is stable, gradually increase the spinning speed step by step to the spinning speed.

[0034] Solidification step: The spinning dope forms a spinning dope filament under the action of the spinneret 1. The spinning dope filament passes through the air layer and enters the coagulation bath 4 to solidify into a nascent fiber.

[0035] Spinning step: Wash, hot stretch, oil, dry and densify, and steam stretch the nascent fiber to obtain polyacrylonitrile carbon fiber precursor.

[0036] In this technical solution, on the one hand, the cutting structure 2 in the liquid supply pipe 12 can cut the spinning dope therein, and then slow down the pressure fluctuation at the moment of spinning by homogenizing the spinning dope, preventing the occurrence of the aforementioned deficiencies of the spinneret 1. On the other hand, by gradually increasing the spinning speed step by step, the viscoelastic energy storage caused by the streamline convergence of the spinning dope at the moment of spinning can be reduced, which can further avoid the bursting of the bursting disc of the spinning component or the bulging and deformation of the spinneret, solve the problem of high instantaneous pressure during the dry-jet wet spinning process, and can prepare polyacrylonitrile carbon fiber precursor with excellent performance, thus promoting the improvement of production efficiency.

[0037] In a specific embodiment, the spinning speed is 7-16 m / min. Through experiments, when the spinning speed is 5-8 m / min, the instantaneous spinning pressure is at a relatively low level and the spinning state is good. Therefore, the preferred solution is that the initial spinning speed is 0.5-0.7 times the spinning speed, and the adjustment range of gradually increasing the spinning speed step by step is 1.5-3.0 m / min.

[0038] The technical solution of the present invention will be further described below in conjunction with several embodiments and comparative examples:

[0039] Example 1

[0040] The spinning dope with a solid content of 21% and a viscosity of 110 Pa·s is filtered and then subjected to cutting treatment. The number of cutting units (i.e., cutting disks 21, the same below) is 15, and the number of cuts of the spinning dope is 2 15 = 32768. The length of the cutting unit is 30 mm, the torsional diameter is 20 mm, the L / D is 1.5, and the cut spinning dope flows alternately. A temperature control medium is passed through the outer periphery of the cutting unit, and the temperature is 20 °C. The flow direction of the temperature control medium is opposite to that of the spinning dope. During spinning, the fluctuation range of the spinning pressure is 0.2 - 0.8 bar.

[0041] The spinning dope forms a dope stream through the spinneret. The initial spinning speed of the dope stream is 7.5 m / min, and the instantaneous spinning pressure is 16.5 bar; when the spinning pressure slowly drops to 13.8 bar, the spinning speed of the dope stream is adjusted in two steps to 15 m / min (i.e., the spinning speed), the instantaneous pressure is 28.1 bar, and the spinning pressure gradually stabilizes at 22.3 bar after decreasing;

[0042] The spinneret is lowered to a position 5 mm away from the liquid surface of the coagulation bath, and the dope stream enters the coagulation bath to form nascent fibers. The temperature of the coagulation bath is 6 °C, and the concentration of the coagulant water is 65%. Under the condition that the draw ratio in the coagulation bath is 2.67, the nascent fibers enter the water washing at a speed of 40 m / min.

[0043] The nascent fibers are washed with water at a temperature of 50 °C; then they are subjected to two hot water draws at 85 °C, and the draw ratios are 1.3 and 1.9 respectively; the fibers after hot water draw are oiled once and then dried and densified. The temperature for dry densification is 130 - 170 °C; the fibers after dry densification are subjected to steam draw. The steam draw pressure is 0.6 MPa, and the draw ratio is 3.5. The PAN-based carbon fiber precursor is obtained at a speed of 346 m / min.

[0044] Among them, the fineness of the obtained PAN-based carbon fiber precursor is 1.1 dtex, the CV of the linear density of the precursor yarn is 0.50%, the tensile strength of the precursor is 660 MPa, and the tensile modulus is 14.5 GPa. No material blocks are generated on the surface of the spinneret during the production process, and the number of broken filaments ≤ 1 time / day. The precursor is further processed through processes such as pre-oxidation, carbonization, surface treatment, and sizing to obtain PAN-based carbon fiber. The strength of the PAN-based carbon fiber is 5.10 - 5.50 GPa, and the modulus is 250 ± 10 GPa.

[0045] Example 2

[0046] The spinning dope with a solid content of 21% and a viscosity of 110 Pa·s is filtered and then subjected to cutting treatment. The number of cutting units is 12, and the number of cuts of the spinning dope is 2 12= 4096. The length of the cutting unit is 36 mm, the torsional diameter is 20 mm, and L / D is 1.8. The spun dope flows alternately after cutting. A temperature control medium is passed through the outer periphery of the cutting unit at a temperature of 20 °C, and the flow direction of the temperature control medium is opposite to that of the spun dope.

[0047] The spun dope forms a dope filament through a spinneret. The initial spinning speed of the dope filament is 7 m / min, and the instantaneous spinning pressure is 15.9 bar; when the spinning pressure slowly drops to 14.5 bar, the spinning speed of the dope filament is adjusted step by step to 10 m / min (i.e., the spinning speed), the instantaneous pressure is 21.5 bar, and the spinning pressure gradually stabilizes at 15.3 bar during spinning. During spinning, the fluctuation range of the spinning pressure is 0.2 - 0.8 bar.

[0048] The spinneret is lowered to a position 5 mm away from the surface of the coagulation bath, and the dope filament enters the coagulation bath to form a nascent fiber. The temperature of the coagulation bath is 6 °C, and the concentration of the coagulant water is 65%. Under the condition that the draw ratio in the coagulation bath is 3.0, the nascent fiber enters the water washing at a speed of 30 m / min.

[0049] The nascent fiber is washed with water at a temperature of 50 °C; then it undergoes two hot water draws at 85 °C with draw ratios of 1.4 and 2.0 respectively; the fiber after hot water draw is oiled once and then dried and densified. The temperature for dry densification is 150 - 170 °C; the fiber after dry densification is subjected to steam draw. The steam draw pressure is 0.6 MPa, and the draw ratio is 4.0, and the PAN carbon fiber precursor is obtained at a speed of 336 m / min.

[0050] Among them, the fineness of the obtained PAN carbon fiber precursor is 0.8 dtex, the CV of the linear density of the precursor filament is 0.55%, the tensile strength of the precursor filament is 800 MPa, and the tensile modulus is 17 GPa. No material block is generated on the surface of the spinneret during the production process, and the number of broken filaments ≤ 1 time / day. The precursor filament is further processed through processes such as pre-oxidation, carbonization, surface treatment, and sizing to obtain PAN-based carbon fiber. The strength of the PAN-based carbon fiber is 5.90 - 6.20 GPa, and the modulus is 290 ± 10 GPa.

[0051] Comparative Example 1

[0052] The spun dope with a solid content of 21% and a viscosity of 110 Pa·s reaches the spinneret through a delivery pipe to form a dope filament. A temperature control medium is passed through the outer periphery of the delivery pipe at a temperature of 20 °C, and the flow direction of the temperature control medium is opposite to that of the spun dope.

[0053] The initial spinning speed of the undiluted solution filament is 7.5 m / min, and the instantaneous spinning pressure is 18.5 bar; when the spinning pressure slowly drops to 16.2 bar, the spinning speed of the undiluted solution filament is adjusted in two steps to 15 m / min (i.e., the spinning speed), the instantaneous pressure is 30.6 bar, and the spinning pressure gradually stabilizes at 23.9 bar; during spinning, the fluctuation range of the spinning pressure is 1 - 3 bar.

[0054] Lower the spinneret to a position 5 mm from the surface of the coagulation bath. The undiluted solution filament enters the coagulation bath to form the nascent fiber. The temperature of the coagulation bath is 6°C, and the concentration of the coagulant water is 65%. Under the condition that the draw ratio in the coagulation bath is 2.67, the nascent fiber enters the water washing at a speed of 40 m / min.

[0055] Wash the nascent fiber, and the water washing temperature is 50°C; then it undergoes two hot water draws at 85°C, and the draw ratios are 1.3 and 1.9 respectively; the fiber after hot water draw is oiled once and then dried and densified. The temperature for dry densification is 130 - 170°C; the fiber after dry densification undergoes steam draw, the steam draw pressure is 0.6 MPa, and the draw ratio is 3.5. It is impossible to stably wind and collect the fiber through the steam draw furnace.

[0056] Among them, the fineness of the polyacrylonitrile carbon fiber precursor obtained is 1.1 dtex, the CV of the linear density of the precursor filament is 1.55%, the tensile strength is 630 MPa, and the tensile modulus is 14.0 GPa. During the production process, there are many block materials on the spinneret surface, and there are many flyings and tufts in the collected precursor filaments.

[0057] Comparative Example 2

[0058] Filter the spinning dope with a solid content of 21% and a viscosity of 110 Pa·s, and then perform cutting treatment. The number of cutting units is 15, and the cutting number of the spinning dope is 2 15 = 32768. The length of the cutting unit is 22.5 mm, the torsional diameter is 15 mm, and the L / D is 1.5. The cut spinning dope flows alternately.

[0059] The spinning dope forms an undiluted solution filament through the spinneret. The spinning speed of the undiluted solution filament is 15 m / min, and the instantaneous spinning pressure exceeds 35 bar, triggering the protection function of the bursting disc of the spinning component, and the spinning dope leaks and normal production cannot be carried out.

[0060] It is easy for those skilled in the art to understand that, on the premise of no conflict, the advantageous technical features of the above various methods can be freely combined and superimposed.

[0061] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art of this technology, several improvements and variations can be made without departing from the technical principle of the present invention, and these improvements and variations should also be regarded as within the protection scope of the present invention.

Claims

1. A method for preparing carbon fiber precursor by dry-jet wet spinning, characterized in that, It is carried out by using a spinneret assembly for carbon fiber precursor filaments. The spinneret assembly for carbon fiber precursor filaments includes a spinneret plate (1) and a liquid supply pipe (12). The first end of the liquid supply pipe (12) is communicated with the spinneret plate (1), and the second end of the liquid supply pipe (12) is communicated with a spinning dope filtration and supply component. A cutting structure (2) is provided in the liquid supply pipe (12). When the spinning dope is pumped into the liquid supply pipe (12), the spinning dope can be cut into at least two parts independent in the radial direction of the liquid supply pipe (12) by the cutting structure (2). The cutting structure (2) includes a plurality of cutting blades (21) arranged in sequence along the axial direction of the liquid supply pipe (12). The cutting blade (21) is formed by twisting a rectangular metal thin plate by a preset angle, and the preset angle is greater than 0°. The twisting directions of two adjacent cutting blades (21) are opposite. In the flowing direction of the spinning dope, the cutting blade (21) upstream is the upstream cutting blade, and the cutting blade (21) downstream is the downstream cutting blade. The edge of the upstream cutting blade facing the downstream cutting blade and the edge of the downstream cutting blade facing the upstream cutting blade form an intersection. The method includes the following steps: A spinning step of starting a dope pumping device to pump the spinning dope to be ejected from the spinneret plate (1) at an initial spinning speed, and gradually increasing the spinning speed to a spinning speed in steps after the initial spinning speed is stable. A coagulation step, in which the spinning dope forms a spinning dope fine stream under the action of the spinneret plate (1), and the spinning dope fine stream enters a coagulation bath (4) through an air layer and is coagulated to form a nascent fiber. A spinning step of washing, hot water drawing, oiling, drying and densifying, and steam drawing the nascent fiber to obtain a polyacrylonitrile carbon fiber precursor filament. The initial spinning speed is 0.5 to 0.7 times the spinning speed. The adjustment range for gradually increasing the spinning speed in steps is 1.5 to 3.0 m / min.

2. The method for preparing carbon fiber precursor by dry-jet wet spinning according to claim 1, wherein, The number of the cutting blades (21) is 6 to 30, and / or the preset angle is 180°.

3. The method for preparing carbon fiber precursor by dry-jet wet spinning according to claim 1, characterized in that, The length of the cutting blade (21) in the axial direction of the liquid supply pipe (12) is L, the twisting diameter of the cutting blade (21) is D, and L / D is 1.0 to 2.

0.

4. The method for preparing carbon fiber precursor by dry-jet wet spinning according to claim 1, characterized in that, The cutting structure (2) is detachably assembled in the liquid supply pipe (12).

5. The method for preparing carbon fiber precursor by dry-jet wet spinning according to claim 1, wherein A temperature control unit (3) is arranged around the outer circumferential side of the pipe wall of the liquid supply pipe (12), and the flow direction of the temperature control medium in the temperature control unit (3) is opposite to the flow direction of the spinning dope in the liquid supply pipe (12).

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