Manufacturing method and manufacturing system of carbon fiber precursor

Abstract

The invention discloses a manufacturing method and a manufacturing system of a carbon fiber precursor, which comprises the following steps: spraying a spinning solution through a spinneret plate, drafting through a coagulating bath to obtain a nascent fiber, washing with water, drafting, oiling, drying, and drafting through a steam drafting unit to obtain the carbon fiber precursor; the steam drafting unit comprises a plurality of layers of steam drafting machines which are connected in parallel, the number of spindles of nascent fibers in the coagulating bath is increased along with the increase of the number of the steam drafting machines, and the temperature of the coagulating bath and / or the DMAC concentration are correspondingly adjusted according to the change of the number of spindles of the nascent fibers in the coagulating bath. The method has the advantages that by adjusting the temperature of the coagulating bath and the concentration of DMAC, the densification degree of the nascent fiber in the coagulating bath is improved, meanwhile, the breaking strength of the nascent fiber is improved, the nascent fiber can bear large drafting of a steam drafting unit, and therefore the carbon fiber precursor with high strength and few broken filaments is obtained.

Description

Technical Field

[0001] The invention belongs to the field of chemical fiber production, and in particular, relates to a method and a system for manufacturing carbon fiber precursor. Background Art

[0002] Polyacrylonitrile (PAN)-based carbon fiber is a new material that has developed rapidly in the 1960s. It is widely used in military industries such as satellites, launch vehicles, tactical missiles, and spacecraft because of its light weight, high specific strength, high specific modulus, high temperature resistance, corrosion resistance, wear resistance, fatigue resistance, electrical conductivity, and thermal conductivity. It has become an indispensable material in the aerospace industry. Excellent carbon fiber precursor should have the characteristics of high heat resistance, less pore structure, less surface defects, dense structure, and good tensile properties.

[0003] For the traditional DMAC wet two-step process for manufacturing carbon fiber precursor, the steam drawing process in the process only has one steam drawing machine, and its flexible production efficiency is high, but there is a problem that the fracture strength of the obtained carbon fiber is low, which is lower than 4.5GPA; if the mechanical properties of the DMAC wet two-step process are to be further improved, the process route must be changed and the number of steam drawing machines must be increased, and the transformation cost is very high;

[0004] In addition, for the transformation of the existing process, due to the site limitations of the structure and size of the steam drawing machine, it is impossible to place more supporting coagulation bath devices and other devices. If the output needs to be increased, new plant buildings can only be built, which is costly.

[0005] In addition, the tension of the nascent fibers near the steam drawing machine is too high. Without reducing the spinning speed, production failures such as broken fibers are likely to occur. However, reducing the spinning speed will not effectively improve the process production efficiency, making this solution unable to be applied in actual production.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for manufacturing carbon fiber precursor. By adjusting the operating parameters of the coagulation bath according to the increase of the steam drawing machine, the coagulation rate of the spun fiber is accelerated without changing the process route, and the strength of the spun fiber is improved, thereby solving the problem that the performance of the spun fiber decreases when the processing volume increases, so that the produced carbon fiber precursor can reach the T700 level.

[0008] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: a method for manufacturing carbon fiber precursor, wherein the spinning solution is ejected through a spinneret, and primary fibers are obtained by drawing through a coagulation bath, and then the primary fibers are washed and drawn, oiled, and dried, and then drawn through a steam drawing unit to obtain carbon fiber precursor;

[0009] The steam drawing unit includes multiple layers of steam drawing machines connected in parallel. The number of nascent fiber spindles in the coagulation bath increases with the number of steam drawing machines. The temperature of the coagulation bath and / or the DMAC concentration are adjusted accordingly according to the change in the number of nascent fiber spindles in the coagulation bath.

[0010] Furthermore, the coagulation bath is a multi-stage coagulation bath, and the temperature of each stage of the coagulation bath increases with the increase of the number of primary fiber spindles, and / or the DMAC concentration of each stage of the coagulation bath decreases with the increase of the number of primary fiber spindles.

[0011] Furthermore, when the number of steam drawing machines increases by n layers, the temperature of each coagulation bath is increased by (a*n) times, and the DMAC concentration of each coagulation bath is reduced by (b*n) times;

[0012] Among them, 2%≤a≤8%, 2%≤b≤12%.

[0013] Furthermore, the temperature of the multi-stage coagulation is increased in steps, the temperature of the first stage coagulation bath is between 50-70°C, and the temperature of the last stage coagulation bath is between 80 and 90°C.

[0014] Furthermore, the DMAC concentration of the multi-stage coagulation is decreased step by step, the DMAC concentration of the first stage coagulation bath is between 50% and 70%, and the DMAC concentration of the last stage coagulation bath is between 10% and 30%.

[0015] Further, the coagulation drawing draws the nascent fiber at a first drawing multiple, and the steam drawing draws the nascent fiber at a second drawing multiple;

[0016] The first drafting ratio decreases as the number of layers of the steam drafting machine increases, and the second drafting ratio increases as the number of layers of the steam drafting machine increases.

[0017] Furthermore, when the number of steam drafting machines increases by n layers, the first drafting multiple is correspondingly reduced by (c*n) times, and the second drafting multiple is correspondingly increased by (d*n) times;

[0018] Among them, 4%≤c≤20%; 14%≤d≤30%.

[0019] Further, the spun fibers are drawn by washing at a third drawing multiple, and the spun fibers are drawn by drying at a fourth drawing multiple;

[0020] When the number of steam drafting machines increases by n layers, the third drafting multiple is reduced by (e*n) times, and the fourth drafting multiple is reduced by (f*n) times;

[0021] Among them, 5%≤e≤7%; 4%≤f≤9%;

[0022] Preferably, (1-c)*(1-e)*(1-f)*(1+d)=1.

[0023] A carbon fiber precursor manufacturing system adopts the control method of the carbon fiber precursor manufacturing system as described above, wherein each layer of steam drawing machine is respectively provided with a threading channel for primary fibers to pass through;

[0024] The first guide roller group and the second guide roller group are respectively arranged upstream and downstream of the threading channel. Each bundle of primary fibers produced by the coagulation bath is guided by the first guide roller group to pass through the corresponding threading channel respectively, and then extends downstream through the second guide roller group.

[0025] Furthermore, each wire guide roller group includes at least one wire guide roller and a support roller arranged near the corresponding wire threading channel, and the axis of each wire threading channel is tangent to the peripheral side wall of the corresponding support roller;

[0026] The rotation speeds of the rollers of the godet roller group are equal;

[0027] Preferably, each steam drawing machine is arranged in a vertical direction, and each support roller of each godet roller group is arranged in a vertical direction, and the godet roller closest to the support roller is lower than the lowest support roller, or higher than the highest support roller;

[0028] The vertical tangent of the wire guide roller close to the wire threading channel coincides with the vertical tangent of each corresponding support roller away from the wire threading channel, and each raw wire extends to the second side of the corresponding support roller through the first side of the first wire guide roller.

[0029] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art: by adjusting the operating parameters of the coagulation bath according to the increase of the steam drawing machine, the coagulation rate of the primary fiber is accelerated without changing the process route, and the strength of the primary fiber is improved, so that the produced carbon fiber precursor can reach the T700 level;

[0030] Furthermore, by adjusting the drafting multiples of the coagulation bath and the steam drafting unit, the speed of the nascent fiber in the coagulation bath is reduced, the time of its immersion in the coagulation bath is prolonged, and the strength of the nascent fiber is improved, so that the nascent fiber can withstand the tension during steam drafting, and the broken fiber rate is further reduced.

[0031] Finally, by adding support rollers upstream and downstream of the steam drawing machine, the extension path of each bundle of spun fibers is reasonably adjusted to prevent the spun fibers from scratching the surface of the steam drawing machine.

[0032] At the same time, the invention has a simple structure, significant effects and is suitable for popularization and use.

[0033] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the accompanying drawings:

[0035] Figure 1 It is a structural schematic diagram of a steam drawing unit when a three-layer steam drawing machine is used in the present invention.

[0036] In the figure: 1, first guide roller group; 2, steam drawing machine; 201, threading channel; 3, second guide roller group; 4, guide roller; 5, support roller; 6, nascent fiber.

[0037] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0039] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] like Figure 1 As shown, in an embodiment of the present invention, a method for manufacturing carbon fiber precursor is introduced, the spinning solution is sprayed out through a spinneret, and the spun fibers 6 are obtained by drawing in a coagulation bath, and then the spun fibers 6 are drawn by a steam drawing unit after being washed, drawn, oiled, and dried; the carbon fiber precursor is obtained by drawing by the steam drawing unit; the steam drawing unit includes a plurality of parallel steam drawing machines 2, the number of spindles of the spun fibers 6 in the coagulation bath increases with the increase in the number of steam drawing machines 2, and the temperature of the coagulation bath and / or the DMAC concentration are adjusted accordingly according to the change in the number of spindles of the spun fibers 6 in the coagulation bath.

[0042] In the embodiment of the present invention, the number of steam drawing machines 2 is increased by n layers, and n groups of spinnerets are correspondingly increased in the coagulation bath.

[0043] In the embodiment of the present invention, the number of the spinnerets increases with the increase in the number of the steam drawing machines 2, and the number of the spinnerets is controlled between 30 and 120.

[0044] In an embodiment of the present invention, the coagulation bath is a multi-stage coagulation bath, and the temperature of each stage of the coagulation bath increases with the increase of the number of the 6 spindles of the primary fiber, and / or the DMAC concentration of each stage of the coagulation bath decreases with the increase of the number of the 6 spindles of the primary fiber.

[0045] In the embodiment of the present invention, the number of steam drawing machines 2 is increased by n layers, the temperature of each coagulation bath is increased by (a*n) times, and the DMAC concentration of each coagulation bath is reduced by (b*n) times; wherein 2%≤a≤8%, 2%≤b≤12%.

[0046] In the embodiment of the present invention, the temperature of the multi-stage coagulation is gradually increased, the temperature of the first stage coagulation bath is between 50-70°C, and the temperature of the last stage coagulation bath is between 80 and 90°C.

[0047] In the embodiment of the present invention, the DMAC concentration of the multi-stage coagulation is decreased step by step, the DMAC concentration of the first stage coagulation bath is between 50% and 70%, and the DMAC concentration of the last stage coagulation bath is between 10% and 30%.

[0048] In the embodiment of the present invention, the coagulation drawing draws the precursor yarn at a first drawing multiple, and the steam drawing draws the precursor yarn at a second drawing multiple; the first drawing multiple and the second drawing multiple are adjusted accordingly according to the number of layers of the steam drawing machine 2.

[0049] In the embodiment of the present invention, the first drafting ratio decreases as the number of layers of the steam drafting machine 2 increases, and the second drafting ratio increases as the number of layers of the steam drafting machine 2 increases.

[0050] In an embodiment of the present invention, the number of steam drawing machines 2 is increased by n layers, the first drawing multiple is correspondingly reduced by (c*n) times, and the second drawing multiple is correspondingly increased by (d*n) times; 4%≤c≤20%; 14%≤d≤30%; preferably, 6%≤c≤16%; 19%≤d≤26%; further preferably, 8%≤c≤12%; 22%≤d≤24%.

[0051] In an embodiment of the present invention, the spun fiber 6 is drawn by washing with a third drawing multiple, and the spun fiber 6 is drawn by drying with a fourth drawing multiple; the number of steam drawing machines 2 is increased by n layers, the third drawing multiple is correspondingly reduced by (e*n) times, and the fourth drawing multiple is correspondingly reduced by (f*n) times; wherein, 5%≤e≤7%; 4%≤f≤9%; (1-c)*(1+d)*(1-e)*(1-f)=1; preferably, 5.5%≤e≤6.3%; 6%≤f≤7%;.

[0052] In the embodiment of the present invention, in the oiling process, the length of the oiling immersion length does not change with the increase in the number of steam drawing machines 2.

[0053] In the embodiment of the present invention, in the drying process, 10-30 steam hot rollers are used for drying, and the temperature of each steam hot roller is increased step by step.

[0054] In an embodiment of the present invention, the temperature of each steam hot roller in the drying process increases as the number of steam drawing machines 2 increases; preferably, the number of steam drawing machines 2 increases by n layers, and the temperature of each steam hot roller increases by (e*n) times accordingly; wherein 4%≤e≤20%; preferably, e=15%.

[0055] In the embodiment of the present invention, the temperature of the first steam hot roller is greater than or equal to 60° C. and less than or equal to 90° C.; the temperature of the last steam hot roller is greater than or equal to 150° C. and less than or equal to 175° C.

[0056] In an embodiment of the present invention, a carbon fiber precursor manufacturing system is also introduced, which adopts a carbon fiber precursor manufacturing method as described above, and each layer of the steam drawing machine 2 is respectively provided with a threading channel 201 for the spun fibers 6 to pass through; the upstream and downstream of the threading channel 201 are respectively provided with a first guide roller group 1 and a second guide roller group 3, and each bundle of spun fibers 6 produced by the coagulation bath is guided by the first guide roller group 1 to pass through the corresponding threading channel 201, and then extend downstream through the second guide roller group 3.

[0057] Through the above arrangement, the spun fibers 6 after oiling and drying are dispersed into the corresponding threading channel 201 of the steam drawing machine 2 through the first guide roller group 1, and then converged and extended downstream through the second guide roller 4, so that the spun fibers 6 are arranged in order, avoiding the entanglement and knotting of the spun fibers 6 during the dispersion and convergence process.

[0058] In an embodiment of the present invention, each wire guide roller group includes at least one wire guide roller 4 and a support roller 5 arranged near the corresponding wire threading channel 201, and the axis of each wire threading channel 201 is tangent to the peripheral side wall of the corresponding support roller 5; the rotation speed of each support roller 5 of the wire guide roller group is equal.

[0059] Through the above arrangement, by setting corresponding support rollers 5, the number of godet rollers does not increase by the same multiple as the number of steam drawing machines 2 increases, thereby reducing the cost of the carbon fiber precursor manufacturing system while ensuring stable operation;

[0060] Furthermore, by making each support roller 5 tangent to the axis of the corresponding wire guide channel, the extension direction of the spun fiber 6 extending downstream from the support roller 5 coincides with the axis of the wire threading channel 201, so that the spun fiber 6 extends straight into the wire threading channel 201;

[0061] Finally, by making the rotation speeds of the supporting rollers 5 of the guide roller groups equal, the linear speeds and drafting multiples of the spun fibers 6 in the threading channels 201 are respectively equal, thereby making the various parameters of the carbon fiber precursors processed by the steam drafting machines 2 equal.

[0062] In the embodiment of the present invention, each wire threading channel 201 is arranged parallel to each other; preferably, each wire threading channel 201 is arranged horizontally.

[0063] In the embodiment of the present invention, the axis of each supporting roller 5 is perpendicular to the axis of the corresponding wire threading channel 201 .

[0064] In an embodiment of the present invention, each bundle of spun fiber 6 is respectively wound on the corresponding support roller 5 through the guide roller 4 of the first guide roller group 1 and extends to the corresponding wire threading channel 201, and then wound on the corresponding support roller 5 of the second guide roller 4 through each wire threading channel 201, and extends to the guide roller 4 of the second guide roller group 3.

[0065] In an embodiment of the present invention, each steam drawing machine 2 is arranged in a vertical direction, and the support rollers 5 of each wire guide roller group are arranged in a vertical direction. The wire guide roller 4 closest to the support roller 5 is lower than the lowest support roller 5, or higher than the highest support roller 5; the vertical tangent of the wire guide roller 4 close to the wire threading channel 201 coincides with the vertical tangent of the corresponding support roller 5 away from the wire threading channel 201, and each raw silk extends to the second side of the corresponding support roller 5 through the first side of the first wire guide roller 4.

[0066] Specifically, each support roller 5 is higher than the corresponding wire guide roller 4, and the horizontal tangent of the upper side wall of each support roller 5 coincides with the axis of the corresponding wire threading channel 201; or, each support roller 5 is lower than the corresponding wire guide roller 4, and the horizontal tangent of the lower side wall of each support roller 5 coincides with the axis of the corresponding wire threading channel 201;.

[0067] Through the above arrangement, each bundle of spun fibers 6 is extended in the vertical direction from the guide roller 4 of the first guide roller group 1, and when extending to the corresponding support roller 5, it is bent 90 degrees in the horizontal direction around the circumferential side of the support roller 5, and then extends into the corresponding threading channel 201 in the horizontal direction; then, the carbon fiber precursors processed by each steam drawing machine 2 are extended downstream from the corresponding threading channel 201 in the horizontal direction, and are bent 90 degrees in the vertical direction around the corresponding support roller 5 of the second guide roller group 3, and then are gathered on the guide roller 4 and extended downstream; the distribution of the spun fibers 6 is made more reasonable, and the entanglement of the spun fibers 6 with each other, or the excessive friction between the spun fibers 6 and the surface of the steam drawing machine 2 causes breakage.

[0068] Example 1

[0069] (1) After the prepared spinning solution is ejected through a spinneret, it enters a multi-stage coagulation bath process to obtain primary fibers 6;

[0070] The DMAC concentration of the first coagulation bath is 70% and the temperature is 50°C; the DMAC concentration of the last coagulation bath is 30% and the temperature is 80°C; and the first draft multiple of the coagulation bath is 2.

[0071] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0072] Among them, the third stretching multiple of water washing and stretching is 1.8, the oiling immersion length of the oiling process is 1.5 meters, and the fourth stretching multiple of the drying process is 1.2; the temperature of the first steam hot roller is 80°C, and the temperature of the last steam hot roller is 170°C.

[0073] (3) guiding the dried spun fibers 6 to a steam drawing unit having two layers of steam drawing machines 2, and each bundle of spun fibers 6 is drawn by a corresponding steam drawing machine 2 to obtain carbon fiber precursors;

[0074] Among them, the second drafting multiple of the steam drafting unit is 1.9;

[0075] The total drafting multiple of the carbon fiber precursor manufacturing system was 10 times, the yarn breakage rate was 63%, and the frequency of hair balls was 65%.

[0076] It should be noted that the broken wire rate refers to the proportion of broken wires in the processing of carbon fiber precursor, which is a key indicator for evaluating the performance of carbon fiber precursor. In addition, the pilling frequency is the number of pills per meter of manufactured carbon fiber precursor. The pilling frequency is related to the performance and process of the carbon fiber precursor. The reduction in the pilling frequency can be used to determine that the performance of the carbon fiber precursor is improved and the process is effectively optimized.

[0077] Example 2

[0078] (1) After the prepared spinning solution is ejected through a spinneret, it enters a multi-stage coagulation bath process to obtain a primary fiber 6;

[0079] The DMAC concentration of the first coagulation bath is 50% and the temperature is 50°C; the DMAC concentration of the last coagulation bath is 10% and the temperature is 80°C; the first drafting multiple of the coagulation bath is 2.4;

[0080] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0081] Among them, the third stretching multiple of water washing and stretching is 1.8, the upstream immersion length of the oiling process is 1.5 meters, and the fourth stretching multiple of the drying process is 1.2; the temperature of the first steam hot roller is 85°C, and the temperature of the last steam hot roller is 170°C.

[0082] (3) guiding the dried spun fibers 6 to a steam drawing unit having three layers of steam drawing machines 2, and each bundle of spun fibers 6 is drawn by a corresponding steam drawing machine 2 to obtain carbon fiber precursors;

[0083] Among them, the second drafting multiple of the steam drafting unit is 1.9;

[0084] The total drafting multiple of the carbon fiber precursor manufacturing system is 10 times, the broken yarn rate is 70%, and the frequency of hair balls is 70%.

[0085] Example 3

[0086] (1) After the prepared spinning solution is ejected through a spinneret, it enters a multi-stage coagulation bath process to obtain a primary fiber 6;

[0087] The DMAC concentration of the first coagulation bath is 70% and the temperature is 70°C; the DMAC concentration of the last coagulation bath is 30% and the temperature is 90°C; the first drafting multiple of the coagulation bath is 2.4;

[0088] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0089] Among them, the third stretching multiple of water washing and stretching is 1.8, the upstream immersion length of the oiling process is 1.5, and the fourth stretching multiple of the drying process is 1.2; the temperature of the first steam hot roller is 90°C, and the temperature of the last steam hot roller is 165°C.

[0090] (3) guiding the dried spun fibers 6 to a steam drawing unit having three layers of steam drawing machines 2, and each bundle of spun fibers 6 is drawn by a corresponding steam drawing machine 2 to obtain carbon fiber precursors;

[0091] Among them, the second drafting multiple of the steam drafting unit is 1.9;

[0092] The total drafting multiple of the carbon fiber precursor manufacturing system is 10 times, the broken yarn rate is 80%, and the frequency of hair balls is 70%.

[0093] Example 4

[0094] (1) After the prepared spinning solution is ejected through a spinneret, it enters a multi-stage coagulation bath process to obtain a primary fiber 6;

[0095] The DMAC concentration of the first coagulation bath is 50% and the temperature is 70°C; the DMAC concentration of the last coagulation bath is 10% and the temperature is 90°C; the first drafting multiple of the coagulation bath is 2.4;

[0096] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0097] Among them, the third stretching multiple of water washing and stretching is 1.8, the upstream immersion length of the oiling process is 1.5 meters, and the fourth stretching multiple of the drying process is 1.2; the temperature of the first steam hot roller is 85°C, and the temperature of the last steam hot roller is 170°C.

[0098] (3) guiding the dried spun fibers 6 to a steam drawing unit having two layers of steam drawing machines 2, and each bundle of spun fibers 6 is drawn by a corresponding steam drawing machine 2 to obtain carbon fiber precursors;

[0099] Among them, the second drafting multiple of the steam drafting unit is 1.9;

[0100] The total drafting multiple of the carbon fiber precursor manufacturing system is 10 times, the yarn breakage rate is 60%, and the frequency of hair balls is 30%.

[0101] Example 5

[0102] (1) After the prepared spinning solution is ejected through a spinneret, it enters a multi-stage coagulation bath process to obtain a primary fiber 6;

[0103] The DMAC concentration of the first coagulation bath is 50% and the temperature is 70°C; the DMAC concentration of the last coagulation bath is 10% and the temperature is 90°C; the first drafting multiple of the coagulation bath is 2.5;

[0104] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0105] Among them, the third stretching multiple of water washing and stretching is 1.7, the upstream immersion length of the oiling process is 1.5, and the fourth stretching multiple of the drying process is 1.15; the temperature of the first steam hot roller is 85, and the temperature of the last steam hot roller is 170.

[0106] (3) guiding the dried spun fibers 6 to a steam drawing unit having three layers of steam drawing machines 2, and each bundle of spun fibers 6 is drawn by a corresponding steam drawing machine 2 to obtain carbon fiber precursors;

[0107] Among them, the second drafting multiple of the steam drafting unit is 2.3;

[0108] The total drafting multiple of the carbon fiber precursor manufacturing system is 10 times, the broken yarn rate is 55%, and the frequency of hair balls is 25%.

[0109] Example 6

[0110] (1) After the prepared spinning solution is ejected through a spinneret, it enters a multi-stage coagulation bath process to obtain a primary fiber 6;

[0111] The DMAC concentration of the first coagulation bath is 60% and the temperature is 60°C; the DMAC concentration of the last coagulation bath is 10% and the temperature is 90°C; and the first draft multiple of the coagulation bath is 2.

[0112] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0113] Among them, the third stretching multiple of water washing and stretching is 1.58, the upstream immersion length of the oiling process is 2, and the fourth stretching multiple of the drying process is 1.07; the temperature of the first steam hot roller is 95, and the temperature of the last steam hot roller is 165.

[0114] (3) guiding the dried spun fibers 6 to a steam drawing unit having four layers of steam drawing machines 2, and each bundle of spun fibers 6 is drawn by a corresponding steam drawing machine 2 to obtain carbon fiber precursors;

[0115] Among them, the second drafting multiple of the steam drafting unit is 2.9;

[0116] The total drafting multiple of the carbon fiber precursor manufacturing system is 10 times, the yarn breakage rate is 15%, and the frequency of hair balls is 10%.

[0117] The present invention compares Examples 3 and 4 and concludes that when the number of layers of the steam drawing machine 2 increases, the broken wire rate of the carbon fiber precursor manufacturing system can be effectively reduced by reducing the DMAC concentration of the coagulation bath; the present invention compares Examples 2 and 4 and concludes that when the number of layers of the steam drawing machine 2 increases, the broken wire rate of the carbon fiber precursor manufacturing system can be effectively reduced by adjusting the temperature of the coagulation bath; the present invention compares Examples 4 and 5 and concludes that when the number of layers of the steam drawing machine 2 increases, the broken wire rate of the carbon fiber precursor manufacturing system can be effectively reduced by adjusting the drafting multiples of each process respectively; by comparing Examples 1, 7, 8 and 9, it can be concluded that when the number of layers of the steam drawing machine 2 increases, the DMAC concentration, temperature and the first and second drafting multiples of the coagulation bath are adjusted accordingly, which can ensure that the broken wire rate of the carbon fiber precursor manufacturing system does not increase, or even decreases.

[0118] Comparative Example 1

[0119] The difference between this comparative example 1 and the above-mentioned embodiment is that the steam drawing unit is provided with only one layer of steam drawing machine 2, and the DMAC concentration, temperature, and the values ​​of the first drawing multiple and the second drawing multiple are adjusted to optimal values ​​respectively.

[0120] (1) After the prepared spinning solution is ejected through 32 groups of spinnerets, it enters a multi-stage coagulation bath process to obtain primary fibers 6;

[0121] The DMAC concentration of the first coagulation bath is 60% and the temperature is 60° C.; the DMAC concentration of the last coagulation bath is 10% and the temperature is 85° C.; and the first draft multiple of the coagulation bath is 2.5.

[0122] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0123] Among them, the third stretching multiple of water washing and stretching is 1.9, the upstream immersion length of the oiling process is 2, and the fourth stretching multiple of the drying process is 1.33; the temperature of the first steam hot roller is 95, and the temperature of the last steam hot roller is 170.

[0124] (3) guiding the dried spun fibers 6 to a steam drawing unit having a layer of a steam drawing machine 2, and each bundle of spun fibers 6 is drawn by the steam drawing machine 2 to obtain carbon fiber precursors;

[0125] Among them, the second drafting multiple of the steam drafting unit is 1.5;

[0126] The total drafting multiple of the carbon fiber precursor manufacturing system is 10 times, the yarn breakage rate is 8%, and the frequency of hair balls is 5%.

[0127] By comparing the broken wire rates of the carbon fiber precursor manufacturing systems of comparative example 1 and implementations 2, 5 and 6, it can be seen that when the number of layers of the steam drawing machine 2 of the steam drawing unit increases, the broken wire rate and the frequency of pilling can be kept unchanged or even lower by adjusting the DMAC concentration, temperature and the drawing multiple of each process.

[0128] Comparative Example 2

[0129] The difference between this comparative example 2 and the above embodiment is that the steam drawing unit has three layers of steam drawing machines 2, and the values ​​of DMAC concentration, temperature and the first and second drawing multiples are the same as those of comparative example 1. 10%

[0130] (1) After the prepared spinning solution is ejected through a spinneret, it enters a multi-stage coagulation bath, is washed and drawn, oiled, and dried to obtain a primary fiber 6;

[0131] The DMAC concentration of the first coagulation bath is 70% and the temperature is 50° C.; the DMAC concentration of the last coagulation bath is 30% and the temperature is 80° C.; and the first draft multiple of the coagulation bath is 2.4.

[0132] (2) The nascent fiber 6 is washed, drawn, oiled, and dried, and then extended to a steam drawing unit;

[0133] Among them, the third stretching multiple of water washing and stretching is 1.8, the upstream immersion length of the oiling process is 1.5 meters, and the fourth stretching multiple of the drying process is 1.2; the temperature of the first steam hot roller is 80°C, and the temperature of the last steam hot roller is 170°C.

[0134] (3) guiding the dried spun fibers 6 to a steam drawing unit having three layers of steam drawing machines 2, and each bundle of spun fibers 6 is drawn by the steam drawing machine 2 to obtain carbon fiber precursors;

[0135] Among them, the second drafting multiple of the steam drafting unit is 1.9;

[0136] The total drafting multiple of the carbon fiber precursor manufacturing system was 10 times, the yarn breakage rate was 67%, and the frequency of hair balls was 68%.

[0137] By comparing the broken wire rates of the carbon fiber precursor manufacturing system of Comparative Example 2 and Example 1, it is found that when the number of layers of the steam drawing machine 2 is increased, if other operating parameters of the carbon fiber precursor manufacturing system are kept unchanged, the broken wire rate of the carbon fiber precursor manufacturing system will increase, and the frequency of pilling will also increase, which cannot be used in actual production.

[0138] Experimental Example 1

[0139] In this experimental example, 3k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 32 spinneret holes 3000 was used, the spinning speed was controlled to be 22m / mmin, the spinning speed of the carbon fiber preparation system was 10 meters, and the number of spindles of the carbon fiber precursor was 40.

[0140] Experimental Example 2

[0141] In this experimental example, 3k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 3000 spindle holes was used, the spinning speed was controlled to be 23m / min, the spinning speed of the carbon fiber preparation system was 10 meters, and the number of spindles of the carbon fiber precursor was 40.

[0142] Experimental Example 3

[0143] In this experimental example, 3k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 3000 spindle holes was used, the spinning speed was controlled to be 24m / min, the spinning speed of the carbon fiber preparation system was 10, and the number of spindles of the carbon fiber precursor was 40.

[0144] Experimental Example 4

[0145] In this experimental example, 3k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 3000 spindle holes was used, the spinning speed was controlled to be 25m / min, the spinning speed of the carbon fiber preparation system was 10, and the number of spindles of the carbon fiber precursor was 40.

[0146] Experimental Example 5

[0147] In this experimental example, 6k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 6000 was used, the spinning speed was controlled to be 22m / min, the spinning speed of the carbon fiber preparation system was 10 meters, and the number of spindles of the carbon fiber precursor was 40.

[0148] Experimental Example 6

[0149] In this experimental example, 6k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 6000 was used, the spinneret speed was controlled to be 23m / min, the spinning speed of the carbon fiber preparation system was 24, and the number of spindles of the carbon fiber precursor was 40.

[0150] Experimental Example 7

[0151] In this experimental example, 6k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 6000 was used, the spinning speed was controlled to be 24m / min, the spinning speed of the carbon fiber preparation system was 10, and the number of spindles of the carbon fiber precursor was 40.

[0152] Experimental Example 8

[0153] In this experimental example, 6k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 6000 was used, the spinning speed was controlled to be 25m / min, the spinning speed of the carbon fiber preparation system was 10 meters, and the number of spindles of the carbon fiber precursor was 40.

[0154] Experimental Example 9

[0155] In this experimental example, 12k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 12000 spinneret holes was used, the spinning speed was controlled to be 22m / min, the spinning speed of the carbon fiber preparation system was 9, and the number of spindles of the carbon fiber precursor was 40.

[0156] Experimental Example 10

[0157] In this experimental example, 12k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 12000 was used, the spinneret speed was controlled to be 23m / min, the spinning speed of the carbon fiber preparation system was 9, and the number of spindles of the carbon fiber precursor was 40.

[0158] Experimental Example 11

[0159] In this experimental example, 12k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 12000 was used, the spinneret speed was controlled to be 15m / min, the spinning speed of the carbon fiber preparation system was 9, and the number of spindles of the carbon fiber precursor was 40.

[0160] Experimental Example 12

[0161] In this experimental example, 12k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 12000 was used, the spinneret speed was controlled to be 20m / min, the spinning speed of the carbon fiber preparation system was 9, and the number of spindles of the carbon fiber precursor was 40.

[0162] Experimental Example 13

[0163] In this experimental example, 24k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 24000 was used, the spinneret speed was controlled to be 22m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 40.

[0164] Experimental Example 14

[0165] In this experimental example, 24k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 24000 was used, the spinneret speed was controlled to be 23m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 40.

[0166] Experimental Example 15

[0167] In this experimental example, 24k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 24000 was used, the spinneret speed was controlled to be 24m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 32.

[0168] Experimental Example 16

[0169] In this experimental example, 24k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 24000 was used, the spinneret speed was controlled to be 20m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 32.

[0170] Experimental Example 17

[0171] In this experimental example, 25k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 25000 spinneret holes was used, the spinning speed was controlled to be 22m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 32.

[0172] Experimental Example 18

[0173] In this experimental example, 25k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 25000 spinneret holes was used, the spinning speed was controlled to be 23m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 32.

[0174] Experimental Example 19

[0175] In this experimental example, 25k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 25000 spinneret holes was used, the spinning speed was controlled to be 24m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 32.

[0176] Experimental Example 20

[0177] In this experimental example, 25k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 25000 spindle holes was used, the spinning speed was controlled to be 25m / min, the spinning speed of the carbon fiber preparation system was 8, and the number of spindles of the carbon fiber precursor was 32.

[0178] Experimental Example 21

[0179] In this experimental example, 35k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 35000 spindle holes was used, the spinning speed was controlled to be 22m / min, the spinning speed of the carbon fiber preparation system was 6, and the number of spindles of the carbon fiber precursor was 24.

[0180] Experimental Example 22

[0181] In this experimental example, 35k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with 35000 spinneret holes was used, the spinning speed was controlled to be 23m / min, the spinning speed of the carbon fiber preparation system was 6, and the number of spindles of the carbon fiber precursor was 24.

[0182] Experimental Example 23

[0183] In this experimental example, 35k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of 35000 was used, the spinning speed was controlled to be 24m / min, the spinning speed of the carbon fiber preparation system was 6, and the number of spindles of the carbon fiber precursor was 24.

[0184] Experimental Example 24

[0185] In this experimental example, 35k carbon fiber precursor was prepared by the preparation method of Example 1, wherein a spinneret with a spinneret hole of x was used, the spinneret speed was controlled to be 25m / min, the spinning speed of the carbon fiber preparation system was x, and the number of spindles of the carbon fiber precursor was 24.

[0186] The present invention tests the properties of the carbon fiber precursors of Experimental Examples 1-24, specifically including nominal fineness, linear density, breaking strength, fineness cv value, breaking elongation, oil content, DMAC content and modulus, and the results are shown in Table 1 below:

[0187] Table 1

[0188]

[0189]

[0190] It can be seen from the above table that the CV values ​​of the linear density of 1-35k carbon fiber precursor produced by the embodiments of the present invention are all less than or equal to 10% over a length of 1m, that is, the linear density stability of the carbon fiber precursor produced in the present invention is good, the product has high uniformity and stability, and is conducive to large-scale production.

[0191] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content suggested above without departing from the scope of the technical solution of the present invention. The implementation scheme in the above embodiment can be further combined or replaced. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the solution of the present invention.

Claims

1. A method for manufacturing carbon fiber precursor, wherein the spinning solution is ejected from a spinneret, and the primary fiber is obtained by drawing in a coagulation bath, and then the primary fiber is washed and drawn, oiled, and dried, and then drawn by a steam drawing unit to obtain the carbon fiber precursor; It is characterized in that The steam drawing unit includes multiple layers of steam drawing machines connected in parallel. The number of nascent fiber spindles in the coagulation bath increases with the number of steam drawing machines. The temperature of the coagulation bath and / or the DMAC concentration are adjusted accordingly according to the change in the number of nascent fiber spindles in the coagulation bath.

2. The method for producing a carbon fiber precursor according to claim 1, It is characterized in that The coagulation bath is a multi-stage coagulation bath, and the temperature of each stage of the coagulation bath increases with the increase of the number of primary fiber spindles, and / or the DMAC concentration of each stage of the coagulation bath decreases with the increase of the number of primary fiber spindles.

3. The method for producing a carbon fiber precursor according to claim 2, It is characterized in that When the number of steam drawing machines increases by n layers, the temperature of each coagulation bath increases by (a*n) times, and the DMAC concentration of each coagulation bath decreases by (b*n) times; Among them, 2%≤a≤8%, 2%≤b≤12%.

4. The method for producing carbon fiber precursor according to claim 3, It is characterized in that The temperature of the multi-stage coagulation is increased in steps, with the temperature of the first stage coagulation bath being between 50-70°C and the temperature of the last stage coagulation bath being between 80 and 90°C.

5. The method for producing carbon fiber precursor according to claim 3, It is characterized in that The DMAC concentration of the multi-stage coagulation is decreased step by step, the DMAC concentration of the first stage coagulation bath is between 50% and 70%, and the DMAC concentration of the last stage coagulation bath is between 10% and 30%.

6. A method for producing a carbon fiber precursor according to any one of claims 1 to 5, It is characterized in that The coagulation drawing draws the nascent fiber at a first drawing multiple, and the steam drawing draws the nascent fiber at a second drawing multiple; The first drafting ratio decreases as the number of layers of the steam drafting machine increases, and the second drafting ratio increases as the number of layers of the steam drafting machine increases.

7. The method for producing carbon fiber precursor according to claim 6, It is characterized in that When the number of steam drafting machines increases by n layers, the first drafting multiple is reduced by (c*n) times, and the second drafting multiple is increased by (d*n) times; Among them, 4%≤c≤20%; 14%≤d≤30%.

8. A method for producing carbon fiber according to claim 7, It is characterized in that The nascent fibers are drawn by washing at a third drawing multiple, and the nascent fibers are drawn by drying at a fourth drawing multiple; When the number of steam drafting machines increases by n layers, the third drafting multiple is reduced by (e*n) times, and the fourth drafting multiple is reduced by (f*n) times; Among them, 5%≤e≤7%; 4%≤f≤9%; Preferably, (1-c)*(1-e)*(1-f)*(1+d)=1.

9. A system for manufacturing carbon fiber precursor, It is characterized in that A control method for a carbon fiber precursor manufacturing system according to any one of claims 1 to 8 is adopted, wherein each layer of the steam drawing machine (2) is respectively provided with a threading channel (201) for the primary fiber (6) to pass through; A first guide roller group (1) and a second guide roller group (3) are respectively arranged upstream and downstream of the threading channel (201); each bundle of spun fibers (6) produced by the coagulation bath is guided by the first guide roller group (1) to pass through the corresponding threading channel (201), and then extends downstream through the second guide roller group (3).

10. A system for manufacturing carbon fiber precursor according to claim 9, It is characterized in that Each wire guide roller group comprises at least one wire guide roller (4) and a support roller (5) arranged close to the corresponding wire threading channel (201), and the axis of each wire threading channel (201) is tangent to the peripheral side wall of the corresponding support roller (5); The rotation speeds of the rollers (5) of the godet roller group are equal; Preferably, each steam drawing machine (2) is arranged in a vertical direction, and each support roller (5) of each godet roller group is arranged in a vertical direction, and the godet roller (4) closest to the support roller (5) is lower than the lowest support roller (5) or higher than the highest support roller (5); The vertical tangent of the guide wire roller (4) on the side close to the wire threading channel (201) coincides with the vertical tangent of each corresponding support roller (5) on the side away from the wire threading channel (201), and each raw wire extends from the first side of the first guide wire roller (4) to the second side of the corresponding support roller (5).

Images