A 75k carbon fiber precursor, a preparation method thereof, a carbon fiber and a washing device

Abstract

The present application provides a kind of 75k carbon fiber precursor and its preparation method and carbon fiber and washing equipment, comprising: several washing tanks, at least one beating roller is respectively arranged in several washing tanks;Or, at least including one washing tank, several beating rollers are arranged in the washing tank;The cross section of beating roller is regular polygon, and the central angle of regular polygon is 18-45 °, the bundle enters washing tank, and is contacted with the edge of beating roller, and beating roller rotates and shakes and washes the bundle by beating.The bundle is pulled to the lower part of beating roller in the present application, and the contact surface of bundle and beating roller changes constantly in the process of bundle running, i.e.the bundle is contacted with the edge of beating roller after entering washing tank, when beating roller rotates, the edge of regular polygon will periodically beat the bundle, and the bundle is pressed down 3-7mm, then it is separated from contact, and the bundle rebounds, so continuous beating and rebounding process can effectively disperse the bundle, reduce the phenomenon of parallel and adhesive silk, improve the dispersity and uniformity of bundle.

Description

Technical Field

[0001] This invention belongs to the field of carbon fiber production technology. Specifically, it relates to a 75k carbon fiber precursor, its preparation method, carbon fiber, and washing equipment. Background Technology

[0002] Carbon fiber is a special fiber composed of carbon elements, possessing properties such as high temperature resistance, friction resistance, electrical conductivity, thermal conductivity, and corrosion resistance. It has a fibrous shape, is flexible, and can be processed into various fabrics. Due to the preferred orientation of the graphite microcrystalline structure of carbon fibers along the fiber axis, it exhibits very high strength and modulus in the fiber axis direction. Furthermore, carbon fibers have a relatively low density, resulting in relatively high specific strength and specific modulus. The main application of carbon fiber is as a reinforcing material, combined with resins, metals, ceramics, and carbon to manufacture advanced composite materials. Among these, carbon fiber reinforced epoxy resin composites exhibit the highest specific strength and specific modulus among existing engineering materials.

[0003] Polyacrylonitrile (PA) fiber precursor is the main raw material for producing carbon fiber and is also a widely used polymer fiber material in clothing, decoration, construction, and flame-retardant fiber preparation. PA fiber precursor can be divided into two categories based on the nominal number of individual fibers contained in each bundle: small bundles and large bundles. For example, a bundle of 3K PA fiber contains 3000 nominal individual fibers, while a bundle of 24K PA fiber contains 24000 nominal individual fibers. 1K–3K PA fiber belongs to the small bundle category and is mainly used in aerospace and military fields, while 12K–25K PA fiber belongs to the large bundle category and is mainly used in industrial and civilian fields.

[0004] With the increase in the number of monofilaments in carbon fiber, the efficiency of production and weaving also increases accordingly, significantly reducing production costs. Currently, large-tow carbon fiber varieties on the market include 24K, 25K, 35K, and 50K, which are widely used in clean energy, construction, and sports and leisure fields. With continuous technological advancements and increasing demands for cost control, developing larger-specification carbon fiber tow products, moving towards "giant tows," and gradually achieving industrialization has become a necessary condition to meet the higher weaving and production efficiency requirements of downstream product customers.

[0005] In major application areas such as wind power, especially in the pultrusion sheet manufacturing process, research on larger tow K-numbers is urgently needed. For example, based on a 50K large tow, the number of monofilaments within the entire bundle needs to be increased by 50%. Simultaneously, the problem of decreased mechanical properties due to uneven monofilament fineness needs to be addressed. Therefore, developing large tow or giant tow products with superior mechanical properties to meet the urgent market demand has become the primary task and objective requirement for the industrialization of carbon fiber.

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

[0007] This invention provides a 75k carbon fiber precursor, its preparation method, carbon fiber, and washing equipment to ensure uniform fiber thickness, avoid filament bundling and adhesion, improve the internal structure of the fiber, reduce microscopic pore defects, and improve the quality and strength of the fiber.

[0008] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0009] A washing apparatus for producing 75k carbon fiber precursor includes:

[0010] A plurality of washing tanks, each of which is provided with at least one beater roller;

[0011] Alternatively, it may include at least a washing tank with several beating rollers installed inside the washing tank;

[0012] The cross-section of the beating roller is a regular polygon with a central angle of 18 to 45°. After the filament enters the washing tank, it comes into contact with the edge of the beating roller, and the beating roller rotates to beat and vibrate the filament for washing.

[0013] Furthermore, several of the washing tanks are arranged in sequence, and the center angle of the beating rollers in different washing tanks is different. Preferably, the center angle of the beating rollers in different washing tanks decreases in sequence, and the filaments pass through several of the beating rollers in order of decreasing center angle.

[0014] Alternatively, several of the patting rollers are arranged sequentially in a washing tank, and the center angles of the several patting rollers are different. Preferably, the center angles of the several patting rollers decrease sequentially, and the filament bundle passes through the several patting rollers in order of decreasing center angle.

[0015] Preferably, the edges of the tapping roller have chamfers.

[0016] Furthermore, the plurality of the patting rollers include at least patting rollers with a center angle of 36 to 45° and patting rollers with a center angle of 18 to 30°. The filament bundle is first patted and shaken by the patting rollers with a center angle of 36 to 45° and then patted and shaken by the patting rollers with a center angle of 18 to 30°.

[0017] Furthermore, guide rollers are respectively provided at both ends of the washing tank, and the slapping roller is arranged between the guide rollers at both ends. The central axes of the guide rollers and the slapping roller are arranged in parallel, and the distance between the guide roller and the bottom wall of the washing tank is greater than the distance between the slapping roller and the bottom wall of the washing tank.

[0018] Preferably, the guide rollers at both ends of the washing tank are spaced at the same distance from the bottom wall of the washing tank, and the distance between them is D1. The distance between the patting rollers and the bottom wall of the washing tank is D2. The difference between the distance D1 and the distance D2 is 3 to 7 mm.

[0019] This invention also provides a method for preparing 75k carbon fiber precursor, comprising the following steps:

[0020] 1) Acrylonitrile, methyl acrylate and itaconic acid are subjected to aqueous suspension polymerization to obtain a polymer, which is then filtered and dried to obtain a powdered polymer;

[0021] 2) Dissolve the powdered polymer in DMAC to obtain the spinning solution;

[0022] 3) The spinning solution is spun through a spinneret with 75,000 holes. After spinning, it is sent to a coagulation bath to form nascent fibers. The nascent fibers are then patted and washed by a tumbling roller with a regular polygonal cross-section. The size of the central angle of the regular polygon is negatively correlated with the spinning speed. The DMAC content in the raw yarn obtained after washing is less than or equal to 450 ppm. After oiling, drying, and drawing, raw yarn with a diameter of 8.5 to 10.99 micrometers is obtained.

[0023] Preferably, in step 3), the nascent fibers are drawn to the bottom of the beating roller in the washing tank. The beating roller rotates, and the edge of the beating roller contacts the fiber bundle, pressing the fiber bundle down by 3-7 mm. Then the edge of the beating roller disengages from the fiber bundle, and the fiber bundle springs back and is pulled out of the washing tank.

[0024] Preferably, the spinning speed is 30-120 m / min.

[0025] Preferably, in step 1), acrylonitrile, methyl acrylate and itaconic acid undergo an aqueous suspension polymerization reaction to obtain a polymer. The polymer is terminated by a chelation reaction, and then filtered and dried to obtain a powdered polymer. The weight average molecular weight of the powdered polymer is not less than 50,000, preferably 50,000-100,000.

[0026] Preferably, in step 2), the powdered polymer is dissolved in DMAC, and the spinning solution is obtained by heating, filtering and temperature adjustment. The mass percentage of polymer in the spinning solution is 17.0% to 24.0%.

[0027] The 75K specification product design has 75,000 single filaments in the entire bundle and 75,000 spinneret holes. The single filament diameter of the 75K carbon fiber precursor is thinner, which realizes the fine denier of the carbon fiber and eliminates filament bundling and adhesion, and solves the problems of low production efficiency and weaving efficiency.

[0028] The nascent fibers are washed by being patted and vibrated by beating rollers. When the edges of the beating rollers come into contact with the fiber bundle, they press the bundle down by 3-7 mm. Then, the edges separate from the fiber bundle, and the bundle springs back and is pulled out of the washing tank. This process not only enhances the washing effect and removes solvent residue, ensuring that the DMAC content in the raw fiber is less than or equal to 450 ppm, but also further improves the uniformity and internal structural stability of the fiber through mechanical action.

[0029] Under the beating action of the beating roller, the homogenization of the fiber is greatly improved, avoiding the problems of yarn doubling and adhesion, making the diffusion of large K number yarn bundles more uniform during the coagulation bath molding process, thereby improving the internal structure of acrylic fiber.

[0030] After washing, the precursor fibers undergo oiling, drying, and drawing processes to ultimately obtain high-quality carbon fiber precursor fibers. The effective beating by the beating rollers during the washing process ensures that the cyclic structure is more radially uniform during pre-oxidation and the low-carbon and high-carbon processes, meeting the heat dissipation requirements of the entire fiber bundle, avoiding the risk of heat-induced melting, thereby reducing microscopic pore defects and improving fiber quality and strength.

[0031] Through the aforementioned process steps and the crucial role of the beating roller, not only is the uniformity of the fibers improved, and the internal structure of the acrylic fibers enhanced, resolving issues of yarn twisting and adhesion, but the cyclic structure during pre-oxidation and the low-carbon and high-carbon processes is also optimized, making it more radially uniform. This meets the heat dissipation requirements of the entire fiber bundle, avoids the risk of heat-induced melting, thereby reducing microscopic pore defects and improving fiber quality and strength. Furthermore, the product's appearance is also enhanced, and the production method is simple, feasible, and easy to control.

[0032] Furthermore, in step 3), the central angle of the polygon is positively correlated with the diameter of the spinneret holes on the spinneret plate and the spacing between adjacent spinneret holes;

[0033] Preferably, the spacing between adjacent spinnerets is 5 to 10 times the orifice diameter;

[0034] Preferably, the diameter of the spinneret orifice is 45–70 micrometers.

[0035] Furthermore, in step 3), the nascent fibers are subjected to patting, vibration, and washing by several sets of patting rollers, and the center angles of the several sets of patting rollers are different.

[0036] Preferably, the several groups of the beating rollers are arranged sequentially along the direction of the filament bundle, and the center angles of the several groups of the beating rollers decrease sequentially.

[0037] Preferably, the center angle of the tapping roller is 18 to 45°;

[0038] Preferably, the filament bundle is first washed by patting and vibrating water with a 36-45° patting roller, and then washed by patting and vibrating water with a 18-30° patting roller.

[0039] Furthermore, in step 3), the nascent fibers are subjected to beating, oscillating and washing by several sets of beating rollers. The several sets of beating rollers are spaced apart. During the operation of the filament bundle, as the spinning speed increases, the distance between adjacent beating rollers decreases.

[0040] The present invention also provides a 75k carbon fiber precursor, wherein the linear density of the 75k carbon fiber precursor is 6.25 to 10.25 g / m;

[0041] Preferably, the 75k carbon fiber precursor is prepared using the water washing equipment described in this invention;

[0042] Preferably, the 75k carbon fiber precursor is prepared by the preparation method described in this invention.

[0043] The present invention also provides a 75k carbon fiber, wherein the elongation at break of the carbon fiber is greater than or equal to 13% and the breaking strength is greater than or equal to 4.3GPA.

[0044] Preferably, the carbon fiber is made from the carbon fiber precursor of this application, and the diameter of the carbon fiber is 5 to 7 micrometers.

[0045] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0046] The cross-section of the beating roller in this invention is designed as a regular polygon with a central angle of 18–45°. Nascent fibers are drawn into the washing tank below the beating roller. The design of the beating roller ensures that the contact surface between the fiber bundle and the roller continuously changes during the fiber bundle's movement. Specifically, after entering the washing tank, the fiber bundle contacts the edges of the beating roller. As the roller rotates, the edges of the regular polygon periodically beat the fiber bundle. The contact between the edges of the beating roller and the fiber bundle presses the fiber bundle down by 3–7 mm, then the contact is released, and the fiber bundle rebounds. This continuous beating and rebound process effectively disperses the fiber bundle, reduces filament bundling and adhesion, and improves the dispersion and uniformity of the fiber bundle.

[0047] Multiple sets of beating rollers are used for combined beating. The size of the center angle of the beating rollers is negatively correlated with the spinning speed. In the initial stage of washing the filament bundle, the fibers are relatively soft and have a large elasticity, making them easy to deform. Therefore, the spinning speed is controlled at a low level, and a low-frequency beating (a larger center angle, such as 36-45 degrees) is used for preliminary oscillation and cleaning. The larger center angle (36-45°, i.e., 8-10 sides) provides a lower beating frequency and a larger oscillation effect, which is suitable for preliminary beating and oscillation of the filament bundle that has just entered the washing tank, so that the solvent residue in the filament bundle can be initially cleaned.

[0048] In the later stages of washing the filament bundle, the spinning speed increases, the fiber orientation is higher, the elasticity is lower, and the fiber is stiffer. It is no longer as easy to deform as in the early stages of production. High-frequency beating (with a smaller center angle, such as 18-30 degrees) is used to thoroughly vibrate and clean the fiber.

[0049] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0050] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0051] Figure 1 1 is a schematic diagram of the assembly structure of the water washing equipment of the present invention;

[0052] Figure 2 1 is a schematic diagram of the assembly structure of another water washing device according to the present invention;

[0053] Figure 3 The image shown is an electron microscope image of the diameter of a single carbon fiber precursor filament in Embodiment 2 of the present invention.

[0054] Figure 4 Figure 1 is a cross-sectional view of the carbon fiber precursor bundle in Embodiment 2 of the present invention;

[0055] Figure 5 1. A cross-sectional view of the carbon fiber precursor bundle in Comparative Example 1 of the present invention;

[0056] Figure 6 The image shows an electron microscope image of the diameter of a single carbon fiber precursor filament in Comparative Example 2 of this invention.

[0057] In the picture:

[0058] 1. Washing tank; 11. First washing tank; 12. Second washing tank; 13. Third washing tank; 21. First tapping roller; 22. Second tapping roller; 23. Third tapping roller; 31. First guide roller; 32. Second guide roller; 33. Third guide roller; 34. Fourth guide roller; 35. Fifth guide roller; 36. Sixth guide roller; 37. Seventh guide roller; 38. Eighth guide roller; 39. Ninth guide roller; 40. Tenth guide roller.

[0059] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0060] To make the objectives, 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 with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0061] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0062] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0063] Example 1

[0064] This embodiment provides a water washing device for producing 75k carbon fiber precursor. Specifically, as shown... Figure 1 As shown, the washing equipment includes multiple washing tanks, such as: a first washing tank 11, a second washing tank 12, and a third washing tank 13; each washing tank is equipped with at least one beating roller. Specifically, the first washing tank 11 is equipped with a first beating roller 21, the second washing tank 12 is equipped with a second beating roller 22, and the third washing tank 13 is equipped with a third beating roller 23.

[0065] A beating roller is a roller device used to process fiber bundles. The cross-section of the beating roller is a regular polygon with a central angle between 18° and 45°. The central angle determines the angle of each edge of the beating roller, which directly affects the beating force and frequency of the beating roller on the fiber bundle during rotation. Preferably, the edges of the beating roller have rounded chamfers.

[0066] The fiber bundle enters the washing tank from the spinning process, where it comes into contact with the edges of the beating rollers. The beating rollers begin to rotate, using the beating action of their edges to vibrate and wash the fiber bundle. Rounded edges are preferred as they do not damage the fiber bundle upon contact. Through continuous rotation and beating of the rollers, the washing effect is ensured, effectively removing residual solvents (such as DMAC) from the fiber bundle, with a residual level of less than or equal to 450 ppm. After washing, the fiber bundle undergoes oiling, drying, and drawing processes to ultimately obtain high-quality 75k carbon fiber precursor.

[0067] Furthermore, several of the washing tanks are arranged in sequence, and the center angles of the beating rollers in different washing tanks are different. That is, the first washing tank 11, the second washing tank 12, and the third washing tank 13 are arranged in sequence, and the center angles of the first beating roller 21 in the first washing tank 11, the second beating roller 22 in the second washing tank 12, and the third beating roller 23 in the third washing tank 13 are different.

[0068] Preferably, the center angles of the first tapping roller 21, the second tapping roller 22, and the third tapping roller 23 decrease sequentially, and the filament bundle passes through the tapping rollers in descending order of center angle. Further, the tapping rollers include at least tapping rollers with center angles of 36–45° and tapping rollers with center angles of 18–30°. The filament bundle is first tapped and washed by the tapping rollers with center angles of 36–45°, and then tapped and washed by the tapping rollers with center angles of 18–30°.

[0069] Furthermore, guide rollers are respectively installed at both ends of the washing tank 1, and the beating roller is positioned between the guide rollers at both ends. The central axes of the guide rollers and the beating roller are parallel, and the distance between the guide rollers and the bottom wall of the washing tank is greater than the distance between the beating rollers and the bottom wall of the washing tank. The guide rollers are roller devices used to guide the yarn bundles through the washing tank 1, ensuring the stability of the yarn bundles' path during the washing process.

[0070] The guide roller and the beater roller are both located near the bottom of the washing tank 1. Specifically, the guide rollers at both ends of the washing tank 1 are spaced at the same distance from the bottom wall of the washing tank, and the distance between them and the bottom wall of the washing tank 1 is D1. The distance between the beater roller and the bottom wall of the washing tank 1 is D2. The difference between the distance D1 and the distance D2 is 3 to 7 mm.

[0071] The beating roller is positioned between the guide rollers at both ends, and the central axes of the guide roller and the beating roller are parallel, ensuring stable transmission of the filament bundle within the washing tank 1. The continuous beating and vibration of the filament bundle by the beating roller effectively removes residual solvents (such as DMAC) from the fibers, improving washing efficiency.

[0072] Both the guide roller and the beating roller are positioned close to the bottom of the washing tank 1, with a distance of D1 between the guide roller and the bottom wall of the washing tank, and a distance of D2 between the beating roller and the bottom wall of the washing tank. The difference between D1 and D2 is 3–7 mm. This precise spacing design ensures that the yarn bundle is effectively beaten when passing through the beating roller without breaking due to excessive pressure, thereby reducing the risk of yarn breakage during production.

[0073] The guide rollers at both ends are spaced at the same distance, and the distance between them and the bottom wall of the washing tank 1 is D1. This symmetrical arrangement ensures a stable transmission path for the filaments as they enter and leave the washing tank. A stable transmission path helps prevent bending, twisting, or knotting of the filaments during washing, improving the reliability of the production process. The difference between distances D1 and D2 is 3–7 mm. This range ensures that the beating effect of the tapping rollers on the filaments is neither too strong nor too weak. Precise distance control allows the tapping rollers to moderately tap the filaments, enhancing the washing effect while avoiding damage to the fibers, ensuring the quality of the final product.

[0074] Specifically, such as Figure 1 As shown, the yarn bundle enters the first washing tank 11 and is first pulled to the first guide roller 31 near the bottom of the first washing tank 11. The first guide roller 31 pulls the yarn bundle to the lower part of the first patting roller 21 located near the middle area of ​​the bottom of the first washing tank 11, and then pulls it to the second guide roller 32, further pulling it out of the first washing tank 11 and into the second washing tank 12.

[0075] The filament bundle enters the second washing tank 12 and is first drawn to the third guide roller 33 near the bottom of the second washing tank 12. The third guide roller 33 then draws the filament bundle to the lower part of the second patting roller 22 located near the middle area of ​​the bottom of the second washing tank 12. The filament bundle is then drawn to the fourth guide roller 34 and further drawn out of the second washing tank 12 into the third washing tank 13.

[0076] The yarn bundle enters the third washing tank 13 and is first pulled to the fifth guide roller 35 near the bottom of the third washing tank 13. The fifth guide roller 35 pulls the yarn bundle to the lower part of the third patting roller 23 located in the middle area of ​​the bottom of the third washing tank 13. Then it is pulled to the sixth guide roller 36 and further pulled out of the third washing tank 13 to enter the next process.

[0077] By employing multiple washing tanks and a series of guide rollers and beater rollers, continuous washing of the fiber bundle is achieved. Firstly, continuous washing more thoroughly removes solvent residue and impurities, improving fiber purity and quality. Secondly, the fiber bundle is stable and controllable during transport, avoiding problems such as twisting and breakage, ensuring consistent washing results. Furthermore, multiple washings increase washing speed and efficiency, accelerating the production rhythm and improving overall production efficiency. Additionally, multiple washings more thoroughly remove solvent residue from the fibers, reducing residual amounts and meeting production requirements and product quality standards. Finally, the design is reasonable, easy to operate, and convenient to control and maintain, improving the stability and reliability of the production line. In summary, this invention helps improve the quality and production efficiency of carbon fiber precursor, meeting industrial production requirements.

[0078] This embodiment also provides another washing device for producing 75k carbon fiber precursor. Specifically, as shown... Figure 2 As shown, the washing equipment includes at least one washing tank 1, and several beating rollers, such as a first beating roller 21, a second beating roller 22, and a third beating roller 23, are installed in the washing tank 1. The cross-section of the beating rollers is a regular polygon, and their central angle is between 18° and 45°. After the yarn bundle enters the washing tank 1, it comes into contact with the edges of the beating rollers, and the yarn bundle is beating and vibrating through the rotation of the beating rollers.

[0079] The cross-section of the beating roller is designed as a regular polygon (e.g., octagon or decagon) with a central angle of 18–45°. This design allows the beating roller to beat the filament bundle at multiple angles and frequencies when rotating.

[0080] The filament bundle enters the washing tank 1 from the spinning process. Inside the washing tank 1, the filament bundle comes into contact with the edges of multiple beating rollers. The beating rollers begin to rotate, and the filament bundle is vibrated and washed using the beating action of their edges. Through the multiple beating of the beating rollers, the washing effect is further enhanced, ensuring that solvent residues (such as DMAC) in the filament bundle are effectively removed, with a residual amount of less than or equal to 450 ppm.

[0081] The aforementioned patting rollers include at least patting rollers with a center angle of 36 to 45° and patting rollers with a center angle of 18 to 30°. The filament bundle is first patted and shaken by the patting rollers with a center angle of 36 to 45° and then patted and shaken by the patting rollers with a center angle of 18 to 30°.

[0082] Guide rollers are respectively installed at both ends of the washing tank 1, and the beating roller is installed between the guide rollers at both ends. The central axes of the guide rollers and the beating roller are parallel. The distance between the guide rollers and the bottom wall of the washing tank is greater than the distance between the beating rollers and the bottom wall of the washing tank. Preferably, the distance between the guide rollers at both ends of the washing tank and the bottom wall of the washing tank is the same, and the distance between them is D1. The distance between the beating rollers and the bottom wall of the washing tank is D2. The difference between the distances D1 and D2 is 3-7 mm.

[0083] Specifically, such as Figure 2 As shown, the inlet and outlet ends of the washing tank 1 are respectively equipped with a seventh guide roller 37 and a tenth guide roller 40. Between the seventh guide roller 37 and the tenth guide roller 40, a first tapping roller 21, a second tapping roller 22, and a third tapping roller 23 are arranged sequentially, with the distance between the first tapping roller 21 and the second tapping roller 22 being greater than the distance between the second tapping roller 22 and the third tapping roller 23. An eighth guide roller 38 is arranged between the first tapping roller 21 and the second tapping roller 22, and a ninth guide roller 39 is arranged between the second tapping roller 22 and the third tapping roller 23. The centerlines of the seventh guide roller 37, the first tapping roller 21, the eighth guide roller 38, the second tapping roller 22, the ninth guide roller 39, the third tapping roller 23, and the tenth guide roller 40 are parallel to each other.

[0084] The yarn bundle enters the washing tank 1 and is first drawn to the seventh guide roller 37. It is then drawn to the lower part of the first slapping roller 21 by the seventh guide roller 37, and then to the upper part of the eighth guide roller 38. It is then drawn to the lower part of the second slapping roller 22 by the eighth guide roller 38, and then to the upper part of the ninth guide roller 39 by the second slapping roller 22. Finally, it is drawn to the lower part of the third slapping roller 23 by the ninth guide roller 39, and finally pulled out of the washing tank 1 by the tenth guide roller 40 to enter the next process.

[0085] This technical solution achieves continuous washing of the filament bundle through precise setting of the guide rollers and beater rollers within the washing tank 1. The multiple guide rollers and beater rollers ensure stable transmission of the filament bundle within the washing tank, preventing twisting and breakage and ensuring consistent washing results. Secondly, the spacing between the beater rollers results in a more uniform washing effect, more thoroughly removing solvent residues and impurities from the fibers, thus improving fiber quality and purity. Furthermore, the parallel arrangement of the guide rollers and beater rollers, along with their parallel alignment along the centerline, makes the entire washing process more stable, easier to operate, and improves the reliability and stability of the production line.

[0086] Example 2

[0087] This embodiment provides a method for preparing 75k carbon fiber precursor and a method for preparing carbon fiber, including the following steps:

[0088] 1) Mix 97.5 wt% acrylonitrile, 1.5 wt% methyl acrylate and 1.0 wt% itaconic acid to obtain a mixture. Then, continuously add the obtained mixture to an aqueous solvent to adjust the concentration of the mixture. Then, carry out an aqueous suspension polymerization reaction to obtain a polymer.

[0089] 2) The polymer is terminated by chelation reaction, and unreacted monomers are removed by stripping tower. Then, salt and water are removed by water washing filter. After granulation and drying, powdered polymer is obtained. The weight average molecular weight of the powdered polymer is 90,000.

[0090] 3) Dissolve the powdered polymer in DMAC, heat to 85°C, filter to obtain filtrate, adjust the temperature of the filtrate to 65°C, and obtain the spinning solution; the mass ratio of powdered polymer to DMAC is 20:80.

[0091] 4) The spinning solution is stably delivered to the spinning solution at a pressure of 1000 kPa through a spinning metering pump. The spinning solution passes through a spinneret with 75,000 holes, the diameter of the spinneret holes is 50 μm, the hole spacing of the spinneret is 0.5 mm, and it is spun at a speed of 35 m / min. Then it enters the DMAC coagulation bath to obtain nascent fibers. The mass concentration of the DMAC coagulation bath is 55%, and the bath temperature is 50 °C.

[0092] 5) The nascent fibers are washed in the water washing process. The water washing process uses ultrasonic oscillation wave washing with an ultrasonic power of 2000w, an oscillation frequency of 125KHZ, and a wave count of 20-35 per meter. The water washing temperature is 80℃. The water washing process includes a first water washing tank 11, a second water washing tank 12, and a third water washing tank 13. The first water washing tank 11 is equipped with a first tapping roller 21 with a center angle of 45°, the second water washing tank 12 is equipped with a second tapping roller 22 with a center angle of 36°, and the third water washing tank 13 is equipped with a third tapping roller 23 with a center angle of 30°.

[0093] The filament bundle enters the first washing tank 11 and is first pulled to the first guide roller 31 near the bottom of the first washing tank 11. The first guide roller 31 pulls the bundle to the lower part of the first patting roller 21 located near the middle area of ​​the bottom of the first washing tank 11, and then pulls it to the second guide roller 32. The bundle is then pulled out of the first washing tank 11 and enters the second washing tank 12.

[0094] The filament bundle enters the second washing tank 12 and is first drawn to the third guide roller 33 near the bottom of the second washing tank 12. The third guide roller 33 then draws the filament bundle to the lower part of the second patting roller 22 located near the middle area of ​​the bottom of the second washing tank 12. The filament bundle is then drawn to the fourth guide roller 34 and further drawn out of the second washing tank 12 into the third washing tank 13.

[0095] The yarn bundle enters the third washing tank 13 and is first pulled to the fifth guide roller 35 near the bottom of the third washing tank 13. The fifth guide roller 35 pulls it to the lower part of the third patting roller 23 located in the middle area of ​​the bottom of the third washing tank 13, and then pulls it to the sixth guide roller 36 to further pull it out of the third washing tank 13.

[0096] The nascent fibers are drawn to the bottom of the beating rollers in each washing tank. The beating rollers rotate, and the edges of the beating rollers contact the fiber bundle, pressing the fiber bundle down by about 5mm. Then the edges of the beating rollers disengage from the fiber bundle, and the fiber bundle springs back and is pulled out from each washing tank. The spinning speed of the fiber bundle in the first washing tank 11 is 90m / min, the spinning speed in the second washing tank 12 is 100m / min, and the spinning speed in the third washing tank 13 is 110m / min.

[0097] 6) After oiling, drying, and stretching, a raw yarn with a linear density of 8.25±2.0% g / m is obtained; the oil concentration is 2.0%; the temperature of the hot rollers during the drying process is 140℃; the number of hot rollers is 30; and the moisture regain is less than the standard moisture regain of 2.0%.

[0098] The total draw ratio of the drawing process is 10 times. The drawing includes wet zone drawing in the washing section and dry zone drawing. The wet zone drawing in the washing section is carried out during the washing process, and the dry zone drawing is carried out during the drying process. The draw ratio of the wet zone drawing in the washing section is 8.0 times, and the draw ratio of the dry zone drawing is 1.5 times.

[0099] 7) The precursor fiber is pre-oxidized, low-temperature carbonized, high-temperature carbonized, surface treated, dried, sized, and dried to obtain 75k carbon fiber, which has a carbon fiber diameter of 5 to 7 micrometers; the pre-oxidation temperature of the pre-oxidation process is 260℃, and the parallel draw ratio is 1.01 to 1.4 times.

[0100] Example 3

[0101] 1) Mix three monomers, acrylonitrile, methyl acrylate and itaconic acid, to obtain a mixture. Then, continuously add the obtained mixture to an aqueous solvent to adjust the concentration of the mixture, and then carry out an aqueous suspension polymerization reaction to obtain a polymer.

[0102] 2) The polymer is terminated by chelation reaction, and unreacted monomers are removed by stripping tower. Then, salt and water are removed by water washing filter, granulation and drying are performed to obtain powdered polymer. The weight average molecular weight of the powdered polymer is 100,000.

[0103] 3) Dissolve the powdered polymer in DMAC, heat to 95°C, filter to obtain filtrate, adjust the temperature of the filtrate to 90°C, and obtain the spinning solution; the mass ratio of powdered polymer to DMAC is 24:76.

[0104] 4) The spinning solution is stably delivered to the spinning solution at a pressure of 1500 kPa through a spinning metering pump. The spinning solution passes through a spinneret with 75,000 holes, the diameter of the spinneret holes is 70 μm, the hole spacing of the spinneret is 0.35 mm, and it is spun at a speed of 53 m / min. Then it enters the DMAC coagulation bath to obtain nascent fibers. The mass concentration of the DMAC coagulation bath is 68%, and the bath temperature is 68 °C.

[0105] 5) The nascent fibers are washed in the water washing process. The water washing process uses ultrasonic oscillation wave washing with an ultrasonic power of 3000w, an oscillation frequency of 150KHZ, and a wave number of 30-35 per meter. The water washing temperature is 99℃. The water washing process includes 8 water washing tanks. The first 4 water washing tanks are equipped with a first tapping roller 21 with a center angle of 45°, and the last 4 water washing tanks are equipped with a third tapping roller 23 with a center angle of 30°.

[0106] The nascent fibers are drawn to the bottom of the beating rollers in each washing tank. The beating rollers rotate, and the edges of the beating rollers contact the fiber bundle, pressing the fiber bundle down by about 7mm. Then the edges of the beating rollers disengage from the fiber bundle, and the fiber bundle springs back and is pulled out from each washing tank. The spinning speed of the fiber bundle in the first 4 washing tanks is 30m / min, and the spinning speed in the last 4 washing tanks is 60m / min.

[0107] 6) After oiling, drying, and stretching, a raw yarn with a linear density of about 10.25 g / m is obtained; the oil concentration is 3.0%, the temperature of the hot rollers during the drying process is 170℃, the number of hot rollers is 40, and the moisture regain is less than the standard moisture regain of 2.0%.

[0108] The total draw ratio of the drawing process is 11 times. The drawing includes wet zone drawing in the washing section and dry zone drawing. The wet zone drawing in the washing section is carried out during the washing process, and the dry zone drawing is carried out during the drying process. The draw ratio of the wet zone drawing in the washing section is 9.0 times, and the draw ratio of the dry zone drawing is 2.2 times.

[0109] 7) The precursor fiber is pre-oxidized, low-temperature carbonized, high-temperature carbonized, surface treated, dried, sized, and dried to obtain 75k carbon fiber, which has a carbon fiber diameter of 5 to 7 micrometers; the pre-oxidation temperature of the pre-oxidation process is 290℃, and the parallel draw ratio is 1.4.

[0110] Example 4

[0111] 1) Mix three monomers, acrylonitrile, methyl acrylate and itaconic acid, to obtain a mixture. Then, continuously add the obtained mixture to an aqueous solvent to adjust the concentration of the mixture, and then carry out an aqueous suspension polymerization reaction to obtain a polymer.

[0112] 2) The polymer is terminated by chelation reaction, and unreacted monomers are removed by stripping tower. Then, salt and water are removed by water washing filter. After granulation and drying, powdered polymer is obtained. The weight average molecular weight of the powdered polymer is 50,000.

[0113] 3) Dissolve the powdered polymer in DMAC, heat to 65°C, filter to obtain filtrate, adjust the temperature of the filtrate to 50°C, and obtain the spinning solution; the mass ratio of powdered polymer to DMAC is 17:83.

[0114] 4) The spinning solution is stably delivered to the spinning metering pump at a pressure of 300 kPa. The spinning solution passes through a spinneret with 75,000 holes, the diameter of the spinneret holes is 45 μm, the hole spacing of the spinneret is 0.36 mm, and it is spun at a speed of 13 m / min. Then it enters the DMAC coagulation bath to obtain nascent fibers. The mass concentration of the DMAC coagulation bath is 40%, and the bath temperature is 45 °C.

[0115] 5) The nascent fibers are washed in the water washing process. The water washing process uses ultrasonic oscillation wave washing with an ultrasonic power of 1000w, an oscillation frequency of 100KHZ, and a wave number of 20-25 per meter. The water washing temperature is 65℃. The water washing process includes one water washing tank, in which a first patting roller 21 with a center angle of 45° is installed.

[0116] The nascent fibers are drawn to the bottom of the beating rollers in each washing tank. The beating rollers rotate, and the edges of the beating rollers contact the filament bundle, pressing the filament bundle down by about 3mm. Then the edges of the beating rollers disengage from the filament bundle, and the filament bundle springs back and is pulled out of the washing tank. The spinning speed of the filament bundle is 120m / min.

[0117] 6) After oiling, drying, and stretching, a raw yarn with a linear density of about 6.25 g / m is obtained; the oil concentration is 1.0%, the temperature of the hot rollers during the drying process is 110℃, the number of hot roller groups is 20, and the moisture regain is less than the standard moisture regain of 2.0%.

[0118] The total draw ratio of the drawing process is 6 times. The drawing includes wet zone drawing in the washing section and dry zone drawing. The wet zone drawing in the washing section is carried out during the washing process, and the dry zone drawing is carried out during the drying process. The draw ratio of the wet zone drawing in the washing section is 5.0 times, and the draw ratio of the dry zone drawing is 1.1 times.

[0119] 7) The precursor fiber is pre-oxidized, low-temperature carbonized, high-temperature carbonized, surface treated, dried, sized, and dried to obtain 75k carbon fiber, which has a carbon fiber diameter of about 5 micrometers; the pre-oxidation temperature of the pre-oxidation process is 230℃, and the parallel draw ratio is 1.01.

[0120] Example 5

[0121] This embodiment further designs the raw yarn oiling system used in the oiling process of the present invention, as follows:

[0122] The raw silk oiling system includes:

[0123] Upper oil tank, used to hold oil;

[0124] The oil circulation pipeline has an inlet and an outlet that are respectively connected to the upper oil tank. The oil flows into the oil circulation pipeline from the inlet and flows back to the upper oil tank from the outlet.

[0125] An oil replenishment device is connected to the oil circulation pipeline and is used to replenish oil to the oil circulation pipeline;

[0126] The cooling device is installed on the oil circulation pipeline and is located downstream of the oil replenishment device. The oil in the oil circulation pipeline flows through the cooling device to cool down.

[0127] The oil circulation pipeline may include pipes, valves and other components to realize the flow and circulation of oil; the oil replenishment device may include oil tanks, pumps and other components to keep the oil in the oil circulation pipeline sufficient; the cooling device may include heat sinks, fans and other components to control the temperature of the oil.

[0128] A cooling device works by circulating a cooling medium (such as water or refrigerant) into contact with the object that needs cooling (such as an oil circulation pipe), thereby absorbing heat from the object and lowering its temperature. After contacting the object, the cooling medium carries away the absorbed heat through the internal heat dissipation structure of the cooler or is discharged into the external environment, and then it can be recycled again.

[0129] In this embodiment, by setting up an oil replenishment device, oil can be replenished in real time during the oiling process, ensuring that the oil dosage in the system is always at an appropriate level and avoiding uneven oiling caused by insufficient oil. The cooling device ensures that the oil maintains a suitable temperature during circulation, preventing the oil's performance from deteriorating due to high temperatures, thereby ensuring the stability and consistency of the oiling quality.

[0130] As one embodiment of this invention, a circulation pump is installed on the oil circulation pipeline, an oil replenishment device is installed between the inlet end of the oil circulation pipeline and the circulation pump, and a cooling device is installed between the outlet end of the oil circulation pipeline and the circulation pump.

[0131] The circulation pump on the oil circulation pipeline is connected to the oil replenishment device via connecting pipes to ensure stable oil circulation within the pipeline. The oil replenishment device is connected to the upper oil tank and the circulation pump via connecting pipes to replenish the oil in the circulation pipeline in a timely manner. The cooling device is connected to the oil circulation pipeline and the circulation pump via connecting pipes to reduce the temperature of the oil.

[0132] This embodiment enhances the fluidity and circulation efficiency of the oil in the system by adding a circulating pump, thereby improving the working efficiency of the oiling system. Placing the oil replenishment device between the inlet and the circulating pump ensures that the added oil is fully mixed before entering the system, avoiding uneven oil concentration. The placement of the cooling device effectively reduces the temperature rise of the oil due to friction during circulation, further improving system stability.

[0133] In one embodiment of the present invention, the oil replenishment device includes an oil storage tank or reservoir for storing oil, and a supply pipeline connected to the oil circulation pipeline. A connection port is provided on the oil circulation pipeline near the circulation pump, and this connection port is used to connect to the supply pipeline in the oil replenishment device for discharging oil. The outlet end of the supply pipeline is aligned with the connection port to ensure that the oil in the oil replenishment device can flow smoothly into the oil circulation pipeline. The oil flowing into the supply pipeline and the oil inlet end of the oil circulation pipeline flow in opposite directions and counteract each other at the connection point to ensure that the oil is mixed evenly at the connection port.

[0134] By installing a connection port and a circulation pump in the oil agent circulation pipeline, the oil agent replenishment device can effectively replenish the oil agent to the oil agent circulation pipeline. The oil agents flow in opposite directions and counteract each other at the connection port, achieving full mixing and uniform replenishment of the oil agents. This improves the oil agent circulation efficiency and oiling uniformity, reduces oil agent waste, increases oil agent utilization, and makes operation more convenient, providing a strong guarantee for the efficient and stable operation of the raw yarn oiling system.

[0135] In one embodiment of this invention, the oil circulation pipeline further includes a first circulation pipeline and a second circulation pipeline. The first circulation pipeline is located between the inlet end of the oil circulation pipeline and the circulation pump, with a bend at the end near the circulation pump and a connection port located at the bend. The second circulation pipeline is located between the outlet end of the oil circulation pipeline and the circulation pump.

[0136] By designing the end of the first section of the circulation pipeline near the circulation pump as a bent structure, the flow rate of the oil can be effectively buffered, reducing flow rate fluctuations before the oil enters the circulation pump. Simultaneously, a connection port is provided at the bend, ensuring that the added oil and the circulating oil are fully mixed before entering the circulation pump, guaranteeing the uniformity and stability of the oil.

[0137] Furthermore, the oil replenishment device is an important component of the raw yarn oiling system, used to replenish oil to the oil circulation pipeline. The section of the oil circulation pipeline between its connection port and the liquid inlet is coaxial with the liquid supply pipeline.

[0138] This design allows the added oil to flow along a path coaxial with the circulation pipeline, ensuring the stability and uniformity of the added oil. Simultaneously, this coaxial arrangement reduces fluid resistance caused by pipe bends, improving the efficiency of oil addition. Furthermore, the flow of oil along the coaxial path induces a stronger convection effect, promoting mixing and diffusion among the oil particles, further enhancing oil uniformity. Overall, the rational design and arrangement of the oil addition device contributes to improving the working efficiency and oil utilization rate of the raw silk oiling system.

[0139] Preferably, a flow regulating valve is installed on the liquid supply line. The flow regulating valve can precisely control the flow rate of the oil in the liquid supply line, allowing the amount of oil added to be adjusted according to actual needs, thereby ensuring the accuracy and stability of oil replenishment. Furthermore, by adjusting the flow regulating valve, the flow rate and velocity of the oil in the liquid supply line can be controlled, thus affecting the mixing of the oil in the oil circulation line. Adjusting the flow rate appropriately allows the oil to be mixed more evenly in the circulation line, improving the mixing uniformity of the oil.

[0140] The flow control valve allows for flexible adjustment of the oil replenishment amount according to actual needs, avoiding waste caused by excessive or insufficient replenishment and saving production costs. The flow control valve also keeps the oil replenishment amount within a stable range, preventing fluctuations in oil replenishment from affecting system stability and improving system stability and reliability.

[0141] In another embodiment of the present invention, the raw silk oiling system includes:

[0142] An upper oil tank is used to hold oil.

[0143] The oil circulation pipeline has an inlet end and an outlet end that are respectively connected to the upper oil tank. The oil in the upper oil tank flows into the oil circulation pipeline from the inlet end and flows back to the upper oil tank from the outlet end.

[0144] A circulation pump, installed on the oil circulation pipeline, is used to drive the oil to circulate in the pipeline;

[0145] An oil replenishment device is connected to the oil circulation pipeline and is installed between the inlet end of the oil circulation pipeline and the circulation pump. It is used to replenish oil to the oil circulation pipeline.

[0146] A cooling device is installed between the outlet end of the oil circulation pipeline and the circulation pump to reduce the temperature of the oil.

[0147] Buffer tank, connected to the upper oil tank;

[0148] The outlet end of the oil circulation pipeline includes at least two branches, one branch connecting to the upper oil tank and the other branch connecting to the buffer tank; specifically, the first branch connects to the upper oil tank and the second branch connects to the buffer tank.

[0149] A demineralized water addition device, connected to a buffer tank, is used to input demineralized water into the buffer tank. Specifically, the demineralized water addition device has a demineralized water addition pipeline connected to the buffer tank.

[0150] Preferably, a spraying device is installed inside the upper oil tank, and a branch section of the oil circulation pipeline at the outlet end is connected to the spraying device. Specifically, the number and location of the spraying device can be determined according to the size and shape of the upper oil tank. The spray heads of the spraying device can be evenly distributed at the top or bottom of the upper oil tank, or multiple spray heads can be set at different locations as needed to ensure that the oil can be evenly sprayed onto the raw yarn.

[0151] Spraying devices can employ different spraying methods, such as mist spraying and jet spraying. Mist spraying can evenly spray the oil onto the surface of the raw yarn, while jet spraying can achieve coverage over a larger area. The appropriate spraying method should be selected based on the actual situation. The nozzles of the spraying device can be made of different materials and structures, such as metal nozzles and plastic nozzles, to meet different usage requirements.

[0152] Example 6

[0153] In this embodiment, the spinning solution is spun through a spinneret and then sent to a coagulation bath to form nascent fibers. The nascent fibers are then washed, oiled, dried, and drawn to obtain raw yarn, which is then wound by a raw yarn winding cylinder.

[0154] This embodiment provides a processing technology for a raw yarn winding cylinder, including the following steps:

[0155] (1) Raw material preparation: Prepare polymer substrate (such as nylon, PVC or PP) and antistatic materials; among which, nylon is preferred as the polymer substrate, which has better rigidity, wear resistance and is not easily deformed.

[0156] (2) Mixing treatment: Mix the polymer substrate and antistatic material evenly according to a predetermined ratio.

[0157] (3) Molding process: The mixed material is heated and extruded to form a raw filament winding cylinder. The raw filament winding cylinder can be a cylindrical structure with open ends.

[0158] Among them, antistatic materials include one or more of the following: metal ion antistatic agents, conductive microparticles, and phosphate ester compounds.

[0159] This embodiment effectively prevents the entanglement and breakage of the raw filament due to static electricity during the winding process by mixing the polymer substrate with the antistatic material; the polymer substrate, such as nylon, PVC or PP, has excellent mechanical properties, which can ensure the high strength and durability of the raw filament winding drum.

[0160] Example 7

[0161] This embodiment provides a processing technology for a raw yarn winding cylinder, including the following steps:

[0162] (1) Raw material preparation: Prepare polymer base material and antistatic material, including:

[0163] Metal ion antistatic agents include one or more of zinc ions, copper ions, nickel ions, and aluminum ions.

[0164] Conductive microparticles include one or more of the following: carbon black, carbon nanotubes, graphene, silver nanoparticles, and metal oxide particles.

[0165] (3) Mixing treatment: Mix the polymer substrate and the antistatic material evenly according to a predetermined ratio; the predetermined ratio can be designed according to the actual situation, preferably the mass fraction of the polymer substrate is 96.0%-99.9% and the mass fraction of the antistatic material is 0.1%-4.0%.

[0166] (4) Molding process: The mixed materials are heated, extruded and injection molded to obtain the original filament winding cylinder.

[0167] In this embodiment, the addition of conductive microparticles can improve the conductivity of the material, reduce surface resistance, and prevent static electricity accumulation. In other words, the use of metal ion antistatic agents can enhance the antistatic properties of the material and improve its stability and reliability.

[0168] Furthermore, the metal ions include one or more of zinc, copper, nickel, and aluminum ions, which can provide stable antistatic properties and are suitable for electrostatic protection under different environmental conditions. Carbon black, carbon nanotubes, graphene, silver nanoparticles, etc., have excellent conductivity, which can effectively reduce static electricity accumulation and prevent electrostatic discharge; in addition, conductive microparticles such as carbon black, carbon nanotubes, and graphene not only improve antistatic properties but also enhance the mechanical strength and wear resistance of the material.

[0169] Example 8

[0170] This embodiment provides a processing technology for a raw yarn winding cylinder, including the following steps:

[0171] (1) Raw material preparation: Prepare polymer substrate and antistatic material.

[0172] (2) Mixing treatment: Mix the polymer substrate and antistatic material evenly according to a predetermined ratio.

[0173] (3) Molding and processing:

[0174] Method 1: Heat the mixed material, extrude and injection mold it to obtain the original filament winding cylinder.

[0175] Method 2: The polymer substrate and antistatic material are processed into layers, with the polymer substrate as the inner layer and the antistatic material as the outer layer, thus obtaining the original filament winding cylinder.

[0176] This embodiment provides two molding methods: hybrid heated extrusion injection molding and layered processing molding, to adapt to different production needs. The layered structure design, using a polymer substrate as the inner layer and an antistatic material as the outer layer, effectively combines the advantages of both, improving the overall performance of the winding drum. It allows for the selection of appropriate molding processes based on specific application scenarios, enhancing production flexibility and adaptability.

[0177] Method one involves mixing the polymer substrate with the antistatic material and then performing heated extrusion injection molding. This avoids the complexity of layered processing, reduces the complexity of the production process, and improves production efficiency. The extrusion injection molding of the mixed material ensures the uniform distribution of the antistatic material and the polymer substrate, guaranteeing consistent antistatic and mechanical properties of the product. The processing is simple, highly efficient, and can save production costs, improve production efficiency, and reduce product manufacturing costs. It is suitable for manufacturing raw filament winding cylinders of various shapes and sizes, and has wide applicability.

[0178] Method two uses a polymer substrate as the inner layer and an antistatic material as the outer layer, which can fully utilize the characteristics of both materials to improve the overall performance and stability of the winding drum. The use of an antistatic material for the outer layer can effectively prevent static electricity accumulation and improve the antistatic performance of the precursor yarn winding drum.

[0179] Example 9

[0180] This embodiment provides a processing technology for a raw yarn winding cylinder, including the following steps:

[0181] (1) Raw material preparation: Prepare polymer substrate and antistatic material.

[0182] (2) Molding and processing:

[0183] Method 1: Injection molding the polymer substrate and antistatic material in layers.

[0184] Method 2: The polymer substrate and antistatic material are extruded and formed using a twin-screw co-extruder.

[0185] Method 3: First, process the polymer substrate into a winding cylinder substrate, and then coat the outer surface of the winding cylinder substrate with an antistatic coating. Preferably, the coating is applied by spraying, dipping, or brushing.

[0186] Method 4: First, process the polymer substrate into a winding cylinder substrate, prepare the antistatic material into an antistatic film, and then hot press the antistatic film and the winding cylinder substrate together using a hot press.

[0187] Method 5: First, process the polymer substrate into a winding cylinder substrate, and then deposit the antistatic material on the surface of the winding cylinder substrate by physical vapor deposition or chemical vapor deposition.

[0188] This embodiment provides various layered processing methods, including layered injection molding, twin-screw co-extrusion, antistatic coating, hot-press lamination, and physical vapor deposition or chemical vapor deposition, to meet different technical and production needs. By coating, lamination, or deposition, the antistatic material is uniformly distributed on the surface of the winding drum, ensuring the consistency and effectiveness of the antistatic performance. Different processing methods are suitable for different materials and shape designs, providing more choices and process adaptability.

[0189] Example 10

[0190] This invention provides a processing technology for a raw yarn winding cylinder, the specific steps of which are as follows:

[0191] (1) Forming process: forming a raw filament winding cylinder.

[0192] (2) Surface treatment:

[0193] Anti-slip texture structures are formed by etching or machining on the inner and outer peripheral walls of the raw yarn winding cylinder. The anti-slip texture structure is a threaded structure that is spirally arranged along the inner or outer side of the peripheral wall of the raw yarn winding cylinder. Specifically, the inner peripheral wall of the raw yarn winding cylinder is provided with an inner layer thread, and the outer peripheral wall of the raw yarn winding cylinder is provided with an outer layer thread.

[0194] This invention forms a spiral anti-slip texture structure by etching or turning the inner and outer peripheral walls of the raw yarn winding drum. The anti-slip texture structure, i.e., the outer thread, on the outer peripheral wall of the raw yarn winding drum can increase the surface roughness of the raw yarn winding drum, increase the friction between the inner fiber and the winding drum, and make the fiber more firmly wound on the winding drum. The raw yarn is more stable during the winding process, preventing the raw yarn from delaminating and slipping, avoiding problems such as yarn slippage and breakage, reducing product loss, and improving production efficiency.

[0195] The inner thread on the inner circumferential wall of the raw yarn winding drum can increase the friction of the robot arm during the lifting process, improve the stability of the lifting process, and reduce the risk of falling.

[0196] Example 11

[0197] This embodiment provides a raw yarn winding cylinder, manufactured using the processing technology of this invention. The inner and outer peripheral walls of the raw yarn winding cylinder are provided with anti-slip texture structures. Specifically, the anti-slip texture structure is a thread structure spirally arranged along the inner or outer side of the peripheral wall of the raw yarn winding cylinder. The thread profile includes various types, such as: V-shaped thread profile, rectangular thread profile, trapezoidal thread profile, helical tooth profile, circular thread profile, spherical thread profile, etc. Preferably, the thread crest has a chamfer.

[0198] Preferably, the inner side of the peripheral wall of the raw filament winding cylinder is provided with an internal thread structure, and the outer side of the peripheral wall of the raw filament winding cylinder is provided with an external thread structure. Specifically, the inner peripheral wall of the raw filament winding cylinder is provided with an inner layer thread, and the outer peripheral wall of the raw filament winding cylinder is provided with an outer layer thread.

[0199] More specifically, the distance from the crest to the root of the external thread is greater than the distance from the crest to the root of the internal thread, and the pitch of the external thread is greater than the pitch of the internal thread. The distance from the crest to the root of the external thread is 0.5-0.7 mm, the distance from the crest to the root of the internal thread is 0.3-0.5 mm, the pitch of the external thread is 0.6-1.0 mm, and the pitch of the internal thread is 0.2-0.6 mm.

[0200] In this invention, the distance from the crest to the root of the external thread is between 0.5-0.7 mm, and the pitch is 0.6-1.0 mm. The larger distance increases the thread height, which helps improve friction and ensures the filament adheres firmly to the winding drum during winding, preventing slippage and delamination. The larger pitch design results in a smoother thread profile, avoiding excessive sharpness and reducing the risk of cutting the filament. Furthermore, the larger thread height increases the surface area of ​​the winding drum, aiding in heat dissipation. By increasing the surface area in contact with air, heat can dissipate more quickly, reducing performance degradation caused by heat accumulation during filament winding. The wide pitch design further increases heat dissipation channels, allowing for smoother airflow. This design helps maintain a suitable temperature during high-speed winding, preventing deformation or damage to the filament due to high temperatures.

[0201] In this invention, the distance from the crest to the root of the internal thread is 0.3-0.5 mm, and the pitch is 0.2-0.6 mm. This smaller distance results in a denser thread structure with moderate depth. This thread design provides more friction points on the contact surface with the robot arm, increasing friction and effectively improving the robot arm's stability during lifting. Specifically, the 0.3-0.5 mm range ensures that the thread is neither too shallow (affecting friction) nor too deep (weakening the structure), providing an appropriate friction contact surface to ensure the robot arm can firmly grip the winding drum during lifting.

[0202] Furthermore, the smaller pitch design of the internal thread structure makes the thread structure more dense. This dense thread arrangement further increases the contact area between the robot and the winding drum, thereby enhancing the friction. The 0.2-0.6mm pitch ensures the density of the thread distribution, effectively preventing the robot from slipping during the lifting process.

[0203] This invention achieves multiple beneficial effects, such as increasing friction, improving stability during hoisting, preventing robot arm slippage, reducing the risk of falling, optimizing hoisting operations, and improving safety, by rationally designing the distance from the crest to the root of the internal thread structure and the pitch. It ensures that the spiral anti-slip texture structure on the inner circumference of the raw yarn winding drum can provide sufficient friction during robot arm hoisting, thereby improving the stability and safety of hoisting and reducing the risk of accidents during operation.

[0204] Comparative Example 1

[0205] The only difference between this comparative example and Example 2 is that in step 5), the first tapping roller 21, the second tapping roller 22, and the third tapping roller 23 are all replaced with rollers with the same cross-section and are circular.

[0206] according to Figure 4 and Figure 5 visible, Figure 5 The middle portion of the filaments clung together, while Figure 4 The filaments are evenly distributed and do not stick together. That is, by using the present invention, the beating roller can reduce the phenomenon of filament tangling and sticking, and improve the dispersion and uniformity of the filaments.

[0207] Comparative Example 2

[0208] This comparative example uses the following method to prepare 50K carbon fiber precursor:

[0209] (1) Acrylonitrile, methyl acrylate and itaconic acid monomers are mixed in a mass ratio of 93:4:3 to obtain a mixture. The mixture of acrylonitrile, methyl acrylate and itaconic acid is continuously added to water. The weight ratio of water to the mixture is 2.4:1. The polymer is obtained by aqueous suspension polymerization. The intrinsic viscosity of the polymer is 0.22 and the weight average molecular weight is 60,000. The polymer is terminated by adding p-hydroxyanisole to chelate it. The amount of p-hydroxyanisole added is 0.01% of the polymer mass. Then, the unreacted monomers are removed by stripping tower. Then, the salt and water in the wet solid polymer are removed by water washing filter. Finally, the polymer is dried to obtain powdered polymer.

[0210] (2) Dissolve the powdered polymer in DMAC. The mass ratio of the powdered polymer to DMAC is 18:82. Heat the mixture to 80°C for a period of time to obtain a filter gel. Adjust the temperature of the filter gel to 65°C for filtration to obtain the spinning solution. Adjust the temperature of the spinning solution to 75°C for later use.

[0211] (3) The spinning solution obtained in step (2) is passed through a spinneret with 50,000 holes and spun at a speed of 33 m / min. It is then fed into a coagulation bath to form nascent fibers. The coagulation bath is a DMAC aqueous solution with a concentration of 64% and a coagulation temperature of 70°C. The nascent fibers are then washed, oiled, dried, drawn, and set to obtain raw yarn. The washing is performed using a 1000W ultrasonic oscillating wave washing system with an oscillation frequency of 75 kHz, a wave number of 22 waves / meter, and a washing temperature range of 70°C. The washing process is repeated until the DMAC residue is less than 0.1%. The stretching includes wet stretching in the washing section and dry stretching in the dry section. The wet stretching in the washing section is carried out during the washing process, and the dry stretching in the dry section is carried out during the drying process. The stretching ratio of the wet stretching in the washing section is 8.5 times, and the stretching ratio of the dry stretching is 1.4 times. The total stretching ratio is 11.9 times. The oiling concentration is 2.8%. 25 sets of hot rollers are used in the drying process, and the hot roller temperature is 150°C. The moisture regain is less than the standard moisture regain of 2.0%.

[0212] In the above preparation method, the spinneret pressure is 1200 kPa, so that the CV value of the linear density of the monofilament passing through any spinneret hole is not greater than 10%, and the glue output is 4.2 L / min.

[0213] The precursor fiber prepared in this comparative example was pre-oxidized and carbonized to produce 50K carbon fiber. The pre-oxidation temperature was 270°C, and a stretching of 1.01 times was applied.

[0214] The performance of the carbon fiber precursors prepared in Example 2 and Comparative Example 2 were tested respectively, and the results are shown in Table 1 below:

[0215] Table 1:

[0216] project unit 50K 75K contrast Nominal fineness dtex 1.15 1.10 -0.05 Number of monofilament fibers in nominal bundle root 50000 75000 +25000 Linear density g / m 5.75±2.0％ 8.25±2.0％ 2.5 Fracture strength cN / dtex ≧6.30 ≧6.20 -0.100 Elongation at break ％ 15.0±2.0 16.0±2.0 +1 oil content ％ 1.2±0.5 1.2±0.5 0 DMAC content ppm ≤480 ≤450 -30

[0217] As can be seen from the table above, 75K has 75,000 fibers, which is 25,000 more than 50K's 50,000 fibers. This significantly increases the number of monofilaments in each fiber bundle, improves the overall strength and uniformity of the fiber, and makes it suitable for applications requiring higher strength and performance.

[0218] 75K carbon fiber precursor has a higher linear density, which means that 75K carbon fiber contains more monofilaments. This enhances the strength of the entire fiber bundle. Higher strength means that the fiber can withstand greater tensile force and load, making it suitable for high-strength industrial applications.

[0219] The breaking elongation of 75K carbon fiber precursor is 16.0±2.0%, which is 1% higher than that of 50K (15.0±2.0%). This means that 75K fiber can extend longer before breaking, exhibiting better toughness and durability. Furthermore, the DMAC content of 75K carbon fiber precursor is below 450ppm, which is 30ppm lower than that of 50K (480ppm), indicating that 75K fiber has less solvent residue during the production process, contributing to improved fiber purity and environmental performance.

[0220] The carbon fibers prepared in Example 2 and Comparative Example 2 were subjected to performance tests, and the results are shown in Table 2 below:

[0221] Table 2:

[0222] project unit 50K 75K contrast Linear density g / m 3.10±0.05 4.45±0.05 1.35 Fracture strength GPA ≧4.5 ≧4.3 -0.2 Elongation at break ％ ≧13.0 ≧13.0 0 Modulus Gpa 230～245 225～240 -5

[0223] The linear density of 75K carbon fiber is 4.45 g / m, which is 1.35 g / m higher than that of 50K carbon fiber. This indicates that 75K fiber has a greater mass over the same length, meaning it contains more monofilaments and thus has a higher density. Higher linear density fiber bundles are lighter and can withstand greater tensile forces and loads. Their high density and durability reduce the risk of breakage and wear, extending the fiber's lifespan and reducing the frequency of maintenance and replacement.

[0224] The 75K carbon fiber produced by this invention exhibits significant advantages in other key performance indicators while maintaining mechanical properties comparable to 50K carbon fiber. In particular, the higher linear density means that the fiber bundle contains more monofilaments, thereby improving the overall strength and durability of the fiber. Even at high densities, 75K fiber maintains a breaking elongation and modulus comparable to 50K fiber, ensuring its reliability and stability in high-performance applications. More importantly, the high yield of 75K carbon fiber further enhances its economic efficiency and practicality, enabling it to meet the needs of larger-scale production.

[0225] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A washing device for producing 75k carbon fiber precursor, characterized in that: include: A plurality of washing tanks, each of which is provided with at least one beating roller; the center angle of the beating rollers in different washing tanks decreases sequentially, and the filament bundle passes through the plurality of beating rollers in order of decreasing center angle; Alternatively, it may include at least one washing tank, in which a plurality of beating rollers are arranged; the center angles of the plurality of beating rollers decrease sequentially, and the filament bundles pass through the plurality of beating rollers in order of decreasing center angles; The cross-section of the beating roller is a regular polygon with a central angle of 18 to 45°. After the filament enters the washing tank, it comes into contact with the edge of the beating roller, and the beating roller rotates to beat and vibrate the filament for washing.

2. The washing equipment for producing 75k carbon fiber precursor according to claim 1, characterized in that: The edges of the slapping roller have chamfers.

3. The washing equipment for producing 75k carbon fiber precursor according to claim 1, characterized in that: The aforementioned patting rollers include at least patting rollers with a center angle of 36 to 45° and patting rollers with a center angle of 18 to 30°. The filament bundle is first patted and shaken by the patting rollers with a center angle of 36 to 45° and then patted and shaken by the patting rollers with a center angle of 18 to 30°.

4. The washing equipment for producing 75k carbon fiber precursor according to any one of claims 1 to 3, characterized in that: The washing tank is equipped with guide rollers at both ends, and the slapping roller is positioned between the guide rollers at both ends. The central axes of the guide rollers and the slapping roller are parallel, and the distance between the guide roller and the bottom wall of the washing tank is greater than the distance between the slapping roller and the bottom wall of the washing tank.

5. The washing equipment for producing 75k carbon fiber precursor according to claim 4, characterized in that: The guide rollers at both ends of the washing tank are spaced at the same distance from the bottom wall of the washing tank, and the distance between them is D1. The distance between the patting rollers and the bottom wall of the washing tank is D2. The difference between the distance D1 and the distance D2 is 3 to 7 mm.

6. A method for preparing 75k carbon fiber precursor, characterized in that, Includes the following steps: 1) Acrylonitrile, methyl acrylate and itaconic acid are subjected to aqueous suspension polymerization to obtain a polymer, which is then filtered and dried to obtain a powdered polymer; 2) Dissolve the powdered polymer in DMAC to obtain the spinning solution; 3) The spinning solution is spun through a spinneret with 75,000 holes. After spinning, it is sent to a coagulation bath to form nascent fibers. The nascent fibers are then patted and washed by a tumbling roller. The cross-section of the tumbling roller is a regular polygon. The size of the central angle of the regular polygon is negatively correlated with the spinning speed. The DMAC content in the raw yarn obtained after washing is less than or equal to 450 ppm. The raw yarn is then oiled, dried, and drawn to obtain the raw yarn. In step 3), several groups of the beating rollers are arranged sequentially along the direction of the filament bundle, and the center angle of the several groups of the beating rollers decreases sequentially; the center angle of the beating rollers is 18 to 45°.

7. The method for preparing 75k carbon fiber precursor according to claim 6, characterized in that, In step 3), the nascent fibers are drawn to the bottom of the tumbling roller in the washing tank. The tumbling roller rotates and its edge contacts the fiber bundle, pressing the fiber bundle down by 3-7 mm. Then the edge of the tumbling roller disengages from the fiber bundle, and the fiber bundle springs back and is pulled out of the washing tank.

8. The method for preparing 75k carbon fiber precursor according to claim 6, characterized in that, The spinning speed is 30–120 m / min.

9. The method for preparing 75k carbon fiber precursor according to any one of claims 6 to 8, characterized in that, In step 3), the central angle of the polygon is positively correlated with the diameter of the spinneret holes on the spinneret plate and the spacing between adjacent spinneret holes.

10. The method for preparing 75k carbon fiber precursor according to claim 9, characterized in that, The spacing between adjacent spinnerets is 5 to 10 times the orifice diameter.

11. The method for preparing 75k carbon fiber precursor according to claim 9, characterized in that, The diameter of the spinneret orifice is 45–70 micrometers.

12. The method for preparing 75k carbon fiber precursor according to any one of claims 6 to 8, characterized in that, In step 3), the filament bundle is first washed by patting and vibrating water with a 36-45° patting roller, and then washed by patting and vibrating water with a 18-30° patting roller.

13. The method for preparing 75k carbon fiber precursor according to any one of claims 6 to 8, characterized in that, In step 3), the nascent fibers are patted, vibrated and washed by several sets of patting rollers. The several sets of patting rollers are spaced apart. During the operation of the filament bundle, as the spinning speed increases, the distance between adjacent patting rollers decreases.

14. A 75k carbon fiber precursor prepared using the washing equipment as described in any one of claims 1 to 5 or the preparation method as described in any one of claims 6 to 13.

15. The 75k carbon fiber precursor according to claim 14, characterized in that, The linear density of the 75k carbon fiber precursor is 6.25–10.25 g / m.

16. A 75k carbon fiber made from carbon fiber precursor as described in claim 14 or 15.

17. The 75k carbon fiber according to claim 16, characterized in that, The elongation at break of 75k carbon fiber is greater than or equal to 13%, and the breaking strength is greater than or equal to 4.3GPA.

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