Electrostatic treatment device for polyacrylonitrile fiber precursor

Abstract

The utility model provides a polyacrylonitrile fiber precursor electrostatic treatment device which comprises an oil agent tank body, an oil agent containing an antistatic agent is contained in the oil agent tank body, and the oil agent tank body is provided with a yarn inlet end and a yarn outlet end. Polyacrylonitrile fiber precursors can enter the position below the liquid level of the oiling agent through the yarn inlet end and are pulled out through the yarn outlet end, and an electrostatic eliminator is arranged at the yarn inlet end and used for eliminating electrostatic charges carried by the polyacrylonitrile fiber precursors entering the oiling agent tank body. The static electricity eliminator is arranged at the yarn inlet end of the oiling agent tank body, so that static electricity elimination can be carried out on the raw yarn which is placed for a long time, and meanwhile after static electricity on the raw yarn is eliminated, the raw yarn is introduced into the subsequent oiling agent containing the antistatic agent in the oiling agent tank body to be oiled again. Repulsion between monofilaments or between tows caused by static electricity of the tows is effectively eradicated, and then the probability that the tows wind a roller is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of carbon fiber production equipment design technology, specifically relating to an electrostatic treatment device for polyacrylonitrile fiber precursor. Background Technology

[0002] Carbon fiber is a high-strength, high-modulus fiber material with a carbon content of over 95%. It possesses the inherent properties of graphite materials, such as high hardness, high strength, light weight, high chemical resistance, and high temperature resistance, while also having the softness and processability of textile fibers. This makes it popular in aerospace, civil engineering, military, racing, and other competitive sports products.

[0003] The production process of polyacrylonitrile carbon fiber involves unwinding and twisting the wound polyacrylonitrile precursor yarn to improve its strength and abrasion resistance. Pre-oxidation is then performed in a hot air atmosphere, a process divided into multiple oxidation stages, causing the polyacrylonitrile to undergo oxygen absorption and cyclization reactions under the influence of heat and oxygen. After pre-oxidation, the precursor yarn transforms into a heat-resistant trapezoidal structure, which is then further transformed into carbon fiber with a disordered graphite structure through low-temperature and high-temperature carbonization. Generally, the low-temperature carbonization temperature is between 350-900℃, and the high-temperature carbonization temperature is between 1000-1500℃. After carbonization, the surface is chemically treated with ammonium bicarbonate (dilute sulfuric acid) electrolyte to enhance the surface activity of the carbon fiber. The surface electrolyte is then removed by washing with water, and a slurry (epoxy resin) is applied. After drying, the finished product is obtained, ultimately forming carbon fiber with excellent properties such as high strength, high modulus, heat resistance, corrosion resistance, and electrical conductivity. The oxidation and carbonization production line process is divided into five stages: unwinding, oxidation, carbonization, surface treatment, and winding. The carbonization section is further divided into a low-temperature carbonization section and a high-temperature carbonization section; the surface treatment section is further divided into an electrolysis section, a water washing section, a sizing section, and a drying section.

[0004] During the pre-oxidation process, friction between the filaments and between the filaments and the drive rollers generates static electricity as the filaments move. This static electricity causes repulsion between individual filaments and between filament bundles, and the fibers are prone to tangling with the drive rollers during their movement. To eliminate static charges on the filament bundles (pre-oxidized filament bundles themselves are not conductive), existing technologies often place static elimination devices (such as commonly used static eliminators) along the filament bundle's running path. However, since the raw filaments are mostly wound up and stored after the production process, although oil is applied during the raw filament production process to achieve antistatic properties, the oil evaporates over time, reducing the antistatic ability of the raw filaments. Although static elimination devices are used in the carbon fiber production process, the lack of evaporation of the antistatic oil on the raw filaments means that static electricity still occurs between the individual filaments within the bundle and between the filament bundle and the guide rollers during the traction process. Utility Model Content

[0005] Therefore, this utility model provides an electrostatic treatment device for polyacrylonitrile fiber filaments, which can overcome the technical problems in related technologies where polyacrylonitrile fiber filaments are prone to static electricity during the pre-oxidation process, leading to repulsion between filaments and between filament bundles, and the filament bundles are prone to entanglement with rollers.

[0006] To address the aforementioned problems, this utility model provides an electrostatic treatment device for polyacrylonitrile fiber filaments, comprising an oil tank containing an antistatic agent. The oil tank has an inlet end and an outlet end, allowing the polyacrylonitrile fiber filaments to enter below the surface of the oil through the inlet end and be drawn out through the outlet end. An electrostatic eliminator is provided at the inlet end to eliminate the electrostatic charge carried by the polyacrylonitrile fiber filaments entering the oil tank.

[0007] In some embodiments, the height of the static eliminator is adjustable.

[0008] In some embodiments, the infeed end is provided with a first inlet roller, the outfeed end is provided with an outlet roller, the first inlet roller is located between the static eliminator and the outlet roller, and the oil tank is also provided with a first tank roller and a second tank roller located below the liquid surface of the oil, the first tank roller and the second tank roller are respectively arranged to correspond one-to-one with the first inlet roller and the outlet roller, so that the polyacrylonitrile fiber filament is below the liquid surface of the oil.

[0009] In some embodiments, a second inlet roller is also included, which is located on the side of the static eliminator away from the oil tank, and the top surfaces of the second inlet roller and the first inlet roller are on the same horizontal plane.

[0010] In some embodiments, a third inlet roller is also included, which is disposed on the side of the second inlet roller away from the static eliminator, and the top surface of the third inlet roller is below the top surface of the second inlet roller, so as to form a U-shaped guide path with the second inlet roller, the first inlet roller and the first groove roller facing downward for the polyacrylonitrile fiber filament.

[0011] In some embodiments, the ends of the first inlet roller, the outlet roller, the first inner groove roller, the second inner groove roller, the second inlet roller, and the third inlet roller are rotatably connected to the oil tank body via two bearings.

[0012] In some embodiments, the bearing is a maintenance-free bearing; and / or, the second and third inlet rollers are active rollers, and the first inlet roller, outlet roller, first groove roller, and second groove roller are passive rollers.

[0013] In some embodiments, the first inlet roller, the outlet roller, the first inner groove roller, the second inner groove roller, the second inlet roller, and the third inlet roller are made of hard aluminum alloy, and / or the roller surfaces are plasma-sprayed ceramic layers.

[0014] In some embodiments, the diameters of the first inlet roller, the outlet roller, the first inner groove roller, the second inner groove roller, the second inlet roller, and the third inlet roller are 100mm-120mm, and / or the diameter consistency error is <0.01mm.

[0015] In some embodiments, the surface of the outlet roller is formed with a plurality of protruding rings, each of the protruding rings being equally spaced along the axial direction of the outlet roller, a guide groove being formed between two adjacent protruding rings, and the connection position between the protruding rings and the surface of the outlet roller being rounded.

[0016] The electrostatic treatment device for polyacrylonitrile fiber precursor provided by this utility model has the following beneficial effects:

[0017] Installing an electrostatic eliminator at the yarn inlet of the oiling tank can eliminate static electricity from raw yarn that has been stored for a long time. After the static electricity on the raw yarn is eliminated, it is introduced into the subsequent oiling tank containing an antistatic agent for re-oiling. This can improve the generation of frictional static electricity between individual filaments and between the yarn bundle and each guide roller during the traction process, improve the bundle's cohesion, effectively prevent repulsion between individual filaments or between yarn bundles due to static electricity, and thus reduce the probability of yarn bundle entanglement with rollers. Attached Figure Description

[0018] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 This is a three-dimensional structural schematic diagram of the electrostatic treatment device for polyacrylonitrile fiber precursor in an embodiment of this utility model;

[0020] Figure 2 yes Figure 1 Side view of the electrostatic treatment device for polyacrylonitrile fiber precursors;

[0021] Figure 3 yes Figure 1 A partial structural diagram of the outlet roller in one embodiment.

[0022] The attached figures are labeled as follows:

[0023] 1. Oil tank; 11. Inlet end; 12. Outlet end; 2. Static eliminator; 31. First inlet roller; 32. Outlet roller; 321. Convex ring; 322. Guide groove; 331. First groove inner roller; 332. Second groove inner roller; 34. Second inlet roller; 35. Third inlet roller; 100. Polyacrylonitrile fiber filament. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0025] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" 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 utility model and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0026] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0027] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0028] See Figures 1 to 3 As shown in the embodiment of this utility model, an electrostatic treatment device for polyacrylonitrile fiber filaments is provided, including an oil tank 1, specifically designed as a box structure with a top opening. The oil tank 1 contains an oil containing an antistatic agent. The oil tank 1 has an inlet end 11 and an outlet end 12. Polyacrylonitrile fiber filaments 100 can enter below the surface of the oil through the inlet end 11 and be drawn out through the outlet end 12. An electrostatic eliminator 2 is provided at the inlet end 11 to eliminate the electrostatic charge carried by the polyacrylonitrile fiber filaments 100 entering the oil tank 1. The aforementioned electrostatic eliminator 2 can be a commercially available centrifugal antistatic device. In a specific embodiment, the product model of the aforementioned electrostatic eliminator 2 is HY-YH681, which is assembled with the oil tank 1 by a corresponding bracket.

[0029] In this technical solution, an electrostatic eliminator 2 is installed at the yarn inlet 11 of the oil tank 1 to eliminate static electricity from the raw yarn that has been left for a long time. At the same time, after the static electricity on the raw yarn is eliminated, it is introduced into the subsequent oil tank 1 containing an antistatic agent for re-oiling. This can improve the generation of frictional static electricity between the individual filaments in the yarn bundle and between the yarn bundle and each guide roller during the traction process, improve the bundle's cohesion, effectively prevent the repulsion between individual filaments or between yarn bundles caused by static electricity, and thus reduce the probability of yarn bundle wrapping around the rollers.

[0030] In selecting the static eliminator 2, it is important to ensure that the static eliminator 2 generates ions at a high frequency, has a fast static neutralization speed, and has an adjustable positive and negative ion output ratio and frequency. Ideally, the static eliminator 2 should have an ion balance (final residual voltage) ≤ ±20V and a static elimination speed ≤ 0.2s.

[0031] In some embodiments, the height of the static eliminator 2 is adjustable to increase the distance between the static eliminator 2 and different wire bundle diameters, ensuring effective elimination of static electricity. In one feasible embodiment, the support of the static eliminator 2 is reliably connected to the side wall of the oil tank 1 via a long slot and screws, thereby allowing the height of the static eliminator 2 to be adjusted according to the size span of the long slot. In another feasible embodiment, a telescopic component (not shown in the figure) is provided between the static eliminator 2 and the wall of the oil tank 1. The telescopic component is preferably a linear telescopic module to ensure the accuracy of height adjustment. In a specific embodiment, the distance between the height of the static eliminator 2 and the wire bundle is adjustable within the range of 15mm-50mm.

[0032] In some embodiments, the infeed end 11 is provided with a first inlet roller 31, and the outlet end 12 is provided with an outlet roller 32. The first inlet roller 31 is located between the static eliminator 2 and the outlet roller 32. The oil tank 1 is also provided with a first tank roller 331 and a second tank roller 332 located below the liquid surface of the oil. The first tank roller 331 and the second tank roller 332 are respectively arranged corresponding to the first inlet roller 31 and the outlet roller 32, so that the polyacrylonitrile fiber filament 100 is below the liquid surface of the oil.

[0033] In this technical solution, the position of the polyacrylonitrile fiber filament 100 above and below the oil liquid surface is changed by the combined action of the first inlet roller 31, the outlet roller 32, the first groove roller 331, and the second groove roller 332, which can prevent wear on the polyacrylonitrile fiber filament 100.

[0034] In some embodiments, a second inlet roller 34 is also included, which is located on the side of the static eliminator 2 away from the oil tank 1, and the top surface of the second inlet roller 34 is on the same horizontal plane as the top surface of the first inlet roller 31.

[0035] In this technical solution, the second inlet roller 34 and the first inlet roller 31 are located on the left and right sides of the static eliminator 2, respectively, and the top surfaces of the two rollers are on the same horizontal plane. This ensures that the gap between the filament bundle traveling in the top area of ​​the static eliminator 2 and the static eliminator 2 remains uniform and consistent, which is beneficial to improving the reliable performance of static elimination.

[0036] In some embodiments, a third inlet roller 35 is also included, which is disposed on the side of the second inlet roller 34 away from the static eliminator 2, and the top surface of the third inlet roller 35 is below the top surface of the second inlet roller 34, so as to form a U-shaped guide path with the second inlet roller 34, the first inlet roller 31 and the first groove roller 331 for the polyacrylonitrile fiber filament 100 with the inlet roller 34, the first inlet roller 31 and the first groove roller 331 facing downward.

[0037] In this technical solution, the third inlet roller 35, the second inlet roller 34, the first inlet roller 31, and the first groove roller 331 form a reliable position constraint on the polyacrylonitrile fiber filament 100, further enhancing the reliable performance of the static elimination function of the static eliminator 2.

[0038] In some embodiments, the ends of the first inlet roller 31, outlet roller 32, first groove roller 331, second groove roller 332, second inlet roller 34, and third inlet roller 35 are rotatably connected to the oil tank 1 via two bearings (not shown in the figure). That is, the ends of the aforementioned rollers have a double bearing structure, which can ensure the reliable rotation of each roller. In a preferred embodiment, the bearings are maintenance-free bearings, which can reduce maintenance costs.

[0039] In one specific embodiment, the second inlet roller 34 and the third inlet roller 35 are active rollers, and the first inlet roller 31, the outlet roller 32, the first groove roller 331, and the second groove roller 332 are passive rollers.

[0040] In some embodiments, the first inlet roller 31, the outlet roller 32, the first groove roller 331, the second groove roller 332, the second inlet roller 34, and the third inlet roller 35 are made of hard aluminum alloy, and the roller surface is a plasma-sprayed ceramic layer. Specifically, the aforementioned plasma-sprayed ceramic layer is formed by plasma spraying with chromium oxide as the spraying material. In a specific embodiment, the hardness of the plasma-sprayed ceramic layer is not less than HV450, the roughness is Ra0.4-0.6um, and the coating thickness is not less than 0.05mm.

[0041] In some embodiments, the diameters of the first inlet roller 31, outlet roller 32, first groove roller 331, second groove roller 332, second inlet roller 34, and third inlet roller 35 are 100mm-120mm, with a diameter consistency error of <0.01mm. The width of each roller is consistent with the width of the subsequent oxidation furnace, so that the filament bundles can enter the oxidation furnace simultaneously. All of the aforementioned rollers should be statically balanced to ensure that each roller is easy to handle, rotates freely, and operates smoothly.

[0042] In some embodiments, the surface of the exit roller 32 is formed with a plurality of raised rings 321, each of which is equally spaced along the axial direction of the exit roller 32. A guide groove 322 is formed between two adjacent raised rings 321. The connection position between the raised rings 321 and the surface of the exit roller 32 is rounded. It is understood that the positions of the aforementioned guide grooves 322 should correspond one-to-one with the spinning positions in the horizontal direction of the subsequent oxidation furnace. Apart from the raised rings 321 and guide grooves 322 formed on the surface of the exit roller 32, the other rollers are smooth rollers to reduce the risk of wear on the yarn bundle caused by too many grooved rollers.

[0043] In this technical solution, by designing the outlet roller 32 as a grooved roller structure with a guide groove 322 on the roller surface, it is possible to ensure the positional correspondence between the filament bundle pulled out by the device and the subsequent oxidation furnace spinning position, and to prevent the filament bundle from contacting, rubbing, entanglement and other phenomena from occurring before being pulled into the oxidation furnace.

[0044] The following combination Figure 1 The operation method of the technical solution of this utility model is further described as follows:

[0045] like Figure 1 As shown, after the polyacrylonitrile fiber filament 100 is warped on the unwinding machine, it passes through the static eliminator 2 under the tension adjustment of the second inlet roller 34 and the third inlet roller 35 of the active roller. The positive and negative ion output ratio and frequency of the static eliminator 2 are adjusted according to different filaments.

[0046] The fiber bundle is then guided into the oiling tank 1 by the first inlet roller 31. After passing through the first inner roller 331 and the second inner roller 332, the fiber is oiled in the oil containing antistatic agent. Then it is discharged through the outlet roller 32 (groove roller). Each fiber bundle occupies a groove (i.e., the aforementioned guide groove 322). The outlet roller 32 can sort and position the raw filaments and discharge the filaments from the same height.

[0047] The filament bundle enters the oxidation furnace under tension control in a subsequent drawing machine.

[0048] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0049] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above description is only a preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A device for electrostatic treatment of polyacrylonitrile fiber precursors, characterized in that, The device includes an oil tank (1) containing an oil containing an antistatic agent. The oil tank (1) has an inlet end (11) and an outlet end (12). Polyacrylonitrile fiber filaments (100) can enter the liquid surface of the oil through the inlet end (11) and be drawn out through the outlet end (12). An antistatic eliminator (2) is provided at the inlet end (11) to eliminate the static charge carried by the polyacrylonitrile fiber filaments (100) entering the oil tank (1).

2. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 1, characterized in that, The height of the static eliminator (2) is adjustable.

3. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 1, characterized in that, The infeed end (11) is provided with a first inlet roller (31), and the outlet end (12) is provided with an outlet roller (32). The first inlet roller (31) is located between the static eliminator (2) and the outlet roller (32). The oil tank (1) is also provided with a first tank roller (331) and a second tank roller (332) located below the liquid surface of the oil. The first tank roller (331) and the second tank roller (332) are respectively arranged to correspond to the first inlet roller (31) and the outlet roller (32) so that the polyacrylonitrile fiber filament (100) is below the liquid surface of the oil.

4. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 3, characterized in that, It also includes a second inlet roller (34), which is located on the side of the static eliminator (2) away from the oil tank (1), and the top surface of the second inlet roller (34) is on the same horizontal plane as the top surface of the first inlet roller (31).

5. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 4, characterized in that, It also includes a third inlet roller (35), which is disposed on the side of the second inlet roller (34) away from the static eliminator (2), and the top surface of the third inlet roller (35) is below the top surface of the second inlet roller (34) to form a U-shaped guide path with the second inlet roller (34), the first inlet roller (31) and the first groove roller (331) for the polyacrylonitrile fiber filament (100) to open downward.

6. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 5, characterized in that, The ends of the first inlet roller (31), the outlet roller (32), the first groove roller (331), the second groove roller (332), the second inlet roller (34), and the third inlet roller (35) are rotatably connected to the oil tank (1) via two bearings.

7. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 6, characterized in that, The bearing is a maintenance-free bearing; and / or, the second inlet roller (34) and the third inlet roller (35) are active rollers, and the first inlet roller (31), the outlet roller (32), the first groove roller (331), and the second groove roller (332) are passive rollers.

8. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 6, characterized in that, The first inlet roller (31), the outlet roller (32), the first groove roller (331), the second groove roller (332), the second inlet roller (34), and the third inlet roller (35) are made of hard aluminum alloy, and / or the roller surface is plasma-sprayed ceramic layer.

9. The electrostatic treatment device for polyacrylonitrile fiber precursor according to claim 5, characterized in that, The diameters of the first inlet roller (31), the outlet roller (32), the first groove roller (331), the second groove roller (332), the second inlet roller (34), and the third inlet roller (35) are 100mm-120mm, and / or the diameter consistency error is <0.01mm.

10. The electrostatic treatment device for polyacrylonitrile fiber precursors according to claim 3, characterized in that, The surface of the outlet roller (32) is provided with a plurality of protruding rings (321). Each of the protruding rings (321) is equally spaced along the axial direction of the outlet roller (32). A guide groove (322) is formed between two adjacent protruding rings (321). The connection position between the protruding rings (321) and the surface of the outlet roller (32) is rounded.

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