JP2010065339A - Method and apparatus for producing carbon nanotube continuous fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus containing a CNT forming step directly connected with a continuous fiber-forming step and capable of continuously producing a CNT continuous fiber. <P>SOLUTION: The carbon nanotube continuous fiber is produced by introducing a carbon source, a catalyst and a carrier gas into a reaction furnace and continuously forming the carbon nanotube by a flowing vapor-phase CVD step. The step is carried out by discharging the gas and dust from the reaction furnace separately from the carbon nanotube and extracting the formed carbon nanotube into atmosphere. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for producing continuous fibers mainly composed of carbon nanotubes (hereinafter referred to as CNT), which can be an industrial material exceeding the mechanical strength and electrical characteristics of carbon fibers currently industrially produced.

  Although CNT is in the spotlight as a new material for the 21st century, the technology for continuous mass production and the practical production technology for continuously and safely processing continuous fibers made of CNT have not yet been established. The continuous fiber made of CNT is a CNT single yarn having a six-membered ring network (graphene sheet) in a single-layer or multi-layer coaxial tube (one diameter is about 0.6 nm to several tens of nm and the aspect ratio is 1000 or more) is a continuous fiber for practical use in which threads are bundled into a thread shape.

  In order to produce a continuous fiber made of CNTs in large quantities and at low cost, it is necessary to examine from the process of producing CNTs. There are roughly three types of CNT synthesis methods: arc discharge method, laser evaporation method, and chemical vapor deposition method (hereinafter referred to as CVD method). In the CVD method, the catalyst rides in the air stream and enters the reaction system. There are roughly two types: a flowing gas phase CVD method and a substrate CVD method in which a catalyst is fixed to a substrate or the like in a reaction system.

Among these CNT methods, the fluidized gas phase CVD method is the most suitable method for continuously producing CNTs. On the other hand, the substrate CVD method, the arc discharge method, and the laser evaporation method are not suitable for continuous production because they are generated for each batch. In Patent Document 1, a method for manufacturing CNT fibers using the substrate CVD method, that is, a smooth substrate A method is described in which a catalyst of fine particles is supported on the CNTs and CNTs are grown from the catalyst as a starting point, and then a CNT fiber is peeled off from the substrate in a separate process in a batch method. However, it is impossible to produce a large amount of continuous yarns by directly connecting the yarn processing steps, which is not practical as a method for producing continuous fibers.

  Next, Patent Document 2 discloses a fluidized vapor phase CVD method suitable for mass production. Specifically, a carbon raw material containing a precursor or a catalyst having a very small particle size is atomized with a spray or the like and introduced into a high temperature part of the reaction furnace to grow CNT from the catalyst as a starting point. Disclosed is a batch type manufacturing method in which a certain amount is wound around a screw rod and CNT fibers are taken out of the system, and a method in which CNTs are similarly grown and then extracted from a thin tube at the lower end of the reactor with vacuum suction force. Has been. However, in these methods, the pulverized gas and the fine dust of the order of several μm that affects the human body are taken out together with the CNT yarn, so the combustible gas fills the work chamber and explodes or the fine dust is sucked into the human body. There is a risk that. In addition, CNT yarn cannot be produced continuously by the former method of winding in a furnace.

  Patent Document 3 discloses a method for producing CNTs having a relatively uniform diameter and a small amount of impurities by a fluidized gas phase CVD method. However, this method is also a method of capturing CNTs produced on a filter installed in a sealed container provided in the lower part of the high-temperature furnace in a nonwoven fabric state, stopping the operation, and taking it out of the container. Cannot be produced continuously.

  Furthermore, as a method for obtaining continuous fibers containing CNTs, Patent Document 4 discloses a method of obtaining CNT continuous spun yarns by a method in which a CNT sliver is produced in a batch system and then a number of processes are repeated to spin cotton yarn. is described. However, this method also cannot continuously produce CNT continuous fibers.

  Further, as a method for obtaining continuous fibers containing CNTs, Patent Document 5 discloses a method in which CNTs are dispersed in a base material that is a polymer material and spun into yarns. However, although this method can improve the material properties of the base material, it cannot produce continuous fibers from the carbon nanotubes themselves, and the mechanical strength and electrical properties of the current PAN-based and pitch-based carbon fibers can be reduced. No continuous fiber exceeding is obtained.

Thus, a practical method for continuously producing CNT continuous fibers has not yet been found.
Special table 2008-517182 Special table 2007-536434 gazette JP 2006-213590 A JP 2001-115348 A Japanese translation of PCT publication No. 2002-544356

  An object of the present invention is to provide a practical method and apparatus capable of continuously producing CNT continuous fibers, in which a CNT producing process and a continuous fiberizing process are directly connected, and further combustible necessary for the process. It aims at providing the manufacturing method and manufacturing apparatus of a CNT continuous fiber which prevent the fire by sex gas and prevent the spreading | diffusion of the fine dust harmful to the human body which generate | occur | produces in a process.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have reached the following invention in order to produce a large amount of CNT continuous fibers for practical use at low cost.
(1) A carbon source, a catalyst, and a carrier gas are charged into a reaction furnace, and carbon nanotubes are continuously produced by a fluidized gas phase CVD method to obtain continuous carbon nanotube fibers. The carbon nanotubes are discharged separately from the carbon nanotubes, and the produced carbon nanotubes are drawn out to the atmosphere to obtain carbon nanotube continuous fibers.
(2) The method for producing a continuous carbon nanotube fiber according to (1), wherein the carbon nanotube is kept airtight between the reaction furnace and the carbon nanotube when the carbon nanotube is drawn out from the reaction furnace to an air atmosphere.
(3) The method for producing a continuous carbon nanotube fiber according to (1) or (2), wherein the carbon nanotube is twisted when the carbon nanotube is pulled out from the reaction furnace to an air atmosphere.
(4) The method for producing a continuous carbon nanotube fiber according to any one of (1) to (3), wherein a liquid is applied when the carbon nanotube is drawn out from the reaction furnace to an air atmosphere.
(5) Continuously winding the carbon nanotube continuous fiber, and performing at least one treatment of oil agent application, stretching, and twisting on the carbon nanotube continuous fiber until the carbon nanotube continuous fiber is drawn out from the reactor and wound. The manufacturing method of the carbon nanotube continuous fiber in any one of said (1)-(4) to apply.
(6) It has a reaction furnace that continuously generates carbon nanotubes from a carbon source, a catalyst, and a carrier gas by a fluidized gas phase CVD method. The carbon nanotube continuous fiber manufacturing apparatus is characterized by having an outlet for drawing out the carbon nanotube as a continuous fiber.
(7) The continuous carbon nanotube fiber according to (6), wherein the outlet has a sealing unit for keeping an airtight gap between the outlet and the carbon nanotube when the carbon nanotube is pulled out. Manufacturing equipment.
(8) The carbon nanotube continuous fiber manufacturing apparatus according to (7), wherein the sealing means is an elastic member that contacts the carbon nanotube when the carbon nanotube is pulled out.
(9) The carbon nanotube continuous fiber manufacturing apparatus according to (8), wherein the elastic member is a choke seal.
(10) The carbon nanotube continuous fiber manufacturing apparatus according to (8) or (9), further including a mechanism for rotating the elastic member around an axis of the drawn continuous fiber.
(11) The carbon nanotube continuous fiber manufacturing apparatus according to (7), wherein the sealing means is a labyrinth sealing means.
(12) The carbon nanotube continuous fiber manufacturing apparatus according to (7), wherein the sealing means includes a mechanism for supplying a gas having a pressure higher than that inside the reaction furnace to the outlet.
(13) A suction pump is connected to the discharge port, and the sealing means detects a pressure difference between the inside and outside of the reaction furnace, and adjusts the operation capacity of the suction pump according to the sensor. The carbon nanotube continuous fiber manufacturing apparatus according to any one of (6) to (12), further including a control unit.
(14) The carbon nanotube according to (7), wherein the sealing means is a liquid sealing means for supplying a liquid to the inside of the outlet and maintaining airtightness between the liquid and the continuous fiber drawn out. Continuous fiber manufacturing equipment.
(15) A carbon nanotube continuous fiber produced by the method of any one of (1) to (5) or the device of any of (6) to (14).

  According to the present invention, a carbon source, a catalyst, and a carrier gas are charged into a reaction furnace, and carbon nanotubes are continuously generated by a fluidized gas phase CVD method to obtain carbon nanotube continuous fibers. (Combustible carrier gas, unreacted gas, etc.) and dust are separated from the carbon nanotubes and discharged, and the generated carbon nanotubes are drawn to the atmosphere, so that flammable gas and fine dust Continuous carbon nanotube fibers can be produced while preventing diffusion into the air atmosphere. Further, since it is possible to prevent flammable gas and fine dust from leaking into the post-process atmosphere, it is possible to avoid the danger of explosion, fire disaster, and human suction. In addition, since carbon nanotubes can be continuously produced to fiberized, that is, continuous winding of carbon nanotubes can be performed, time loss, space loss, equipment loss, and factor loss, which are adverse effects of process division, can be reduced. Can be obtained efficiently.

1) Description of Apparatus Configuration A continuous fiber manufacturing apparatus according to the present invention includes, for example, a reaction furnace 200 (see FIG. 1) including a reaction tube 2 that generates carbon nanotubes from a carbon source, a catalyst, and a carrier gas. The reaction furnace 200 has a gas and dust outlet 301 and a carbon nanotube outlet 300 at the bottom. Further, on the downstream side of the reaction furnace 200, a CNT continuous fiber take-up section 400 for continuously drawing out the CNTs generated by the reaction furnace 200 to obtain continuous fibers is provided.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. In addition, the following description is for making an understanding of this invention easy, and is not restrict | limited to these specific examples.

  Further, in the present invention, the CNTs drawn out from the reaction furnace 200 are CNTs that are gathered in a state in which each of the smallest CNTs generated in the reaction furnace 200 bundles straws by van der Waals force. A bundle of bundles (with a diameter of about 0.1 μm or less and a length of at least several tens of μm or more), and a continuous state in which carbon nanotubes are substantially connected by continuously pulling out the bundle aggregate Get fiber.

(1) Overall Configuration of CNT Generation Unit In the apparatus shown in FIG. 1, the CNT generation unit includes a reaction tube 2 that generates carbon nanotubes from an input carbon source, a catalyst, and a carrier gas, and 600 to The reactor 200 includes an electric furnace 1 for heating to 1200 ° C. A mixed solution 4 in which a carbon source, a catalyst, and the like are mixed in advance is quantitatively supplied to the reaction furnace 200 by the microfeeder 5, and is supplied to the reaction furnace 2 from the spray nozzle 3. At this time, the carrier gas 7 measured by the carrier gas flow meter 6 is also injected into the reaction furnace 2 from the spray nozzle 3 together with the mixed solution 4.

  The reaction furnace 200 has a sealed box 90 in the lower part, and maintains airtightness between the reaction furnace 200 and the carbon nanotube 401 drawn from the reaction furnace 200. The seal box 90 is provided with a door 97 on the side surface with a transparent window through which the inside can be visually confirmed. In addition, there is a CNT outlet 300 on the lower surface, and the outlet 300 is composed of a receiving tray 93 opened in a funnel shape, a sealing means (described later), etc. downstream thereof. The tray 93 is partially configured in a net shape so as to capture a bundle of bundles of CNTs but allow carrier gas and fine particles to pass therethrough.

  In addition, the lower surface of the seal box 90 is also provided with a gas discharge port 301, which allows unreacted gas generated from a material introduced as a carrier gas or a carbon source, CNT single yarn that has not become continuous fibers, and the like. It is comprised so that the fine dust etc. which are included can be discharged | emitted. The exhaust port 301 is connected to an exhaust pipe 99 and a bubbler 98, and a gas such as a carrier gas passes through the exhaust port 99 and is then discharged out of the system through the fine dust filter 102. Here, the bubbler 98 prevents air from flowing back into the reaction furnace, but it is desirable to install a sensor that can detect even a small amount of oxygen in the reaction furnace.

  As described above, the apparatus of FIG. 1 according to the present invention has a gas and dust outlet at the bottom of the reaction furnace 200 (that is, downstream of the reaction tube in which the CNT single fiber is generated in the CNT moving direction). 301 and a CNT outlet 300.

  In the apparatus shown in FIG. 1, the CNT generator is also provided with a system controller, a system monitor, and the like (not shown).

(2) Sealing means at the CNT outlet 300 As the sealing means at the CNT outlet 300, a seal using an elastic member, a labyrinth seal, a gas seal, a pressure seal, a liquid seal, etc., as described in detail below, are employed. be able to. Among these, it is preferable to select an optimal sealing means according to the production conditions of the CNT continuous fiber.

-Sealing by elastic member An example of the structure of the outlet of the sealed box (CNT outlet 300) will be described in more detail with reference to FIG. In FIG. 2, the seal portion is constituted by an elastic ring 92 (elastic member) having a hole through which CNT passes in the center. The hole of the elastic ring 92 is a small hole or a flat hole that makes light contact with the carbon fiber, and the elastic ring keeps the space between the reaction furnace and the CNT to be drawn out so that gas or the like is brought out of the reaction furnace. Along with the effect of preventing leakage, the ironing effect of reducing the thickness unevenness of the obtained CNT continuous fiber can be obtained.

  The elastic ring 92 preferably has a wear-resistant skin and the inner material is a foamed plastic having a specific gravity of 0.1 or less, and it is preferable to provide a soft elastic sealing function with such a configuration.

  The elastic ring 92 may have a constant cross section with respect to the traveling direction of the CNT continuous fibers, and may be o-shaped, but at least a part of the elastic ring 92 is preferably double-circular with respect to the traveling direction of the CNT continuous fibers. Specifically, for example, as shown in FIG. 2, the downstream side is preferably a double ring shape, and the annular part 193 inside the double ring part is preferably thin and flat as shown in the section AA. At this time, a polyurethane foam pipe 58 having a specific gravity lower than that of the bottom surface of the elastic ring 92 is inserted between the inner annular portion 193 and the outer annular portion 192 so that the inner annular portion 193 is lightly in contact with the drawn CNT. In addition, it is preferable to adjust the press-fitting dimension of the pipe 58 so that the bundle of CNTs can be stably taken out from the sealed box without coming off. Therefore, it is preferable that the pipe 58 has a taper fitting with respect to the inner diameter of the outer annular portion 192 of the elastic ring and is press-fitted to an appropriate length by trial and error.

  In addition, as shown in FIG. 3, it is also preferable to employ a choke seal 92A in which a cavity 194A between the inner annular portion 193A and the outer annular portion 192A of the double annular portion is kept airtight. For example, as shown in the AA cross section of FIG. 3, the choke seal 92 </ b> A has a thin and flat annular portion 193 </ b> A inside the double annular portion, and the CNT continuous fiber 401 is formed inside the inner annular portion 193 </ b> A. When the inner annular portion 193A is pulled out continuously from the hole, the inner annular portion 193A is lightly brought into contact with the drawn CNT continuous fiber 401, and is deformed so as to cut off the flow of gas between the inner annular portion 193A and the outer annular portion 192A. The internal pressure of the cavity 194A is adjusted. By doing so, it is possible to maintain airtightness between the reaction furnace and the CNT to be drawn, and to prevent the omission and obtain a more subtle ironing effect. When adjusting the internal pressure of the cavity 194A, a pneumatic pressure adjusting mechanism 92B is connected to the cavity 194A, and a contact tension meter (not shown) is provided near the seal outlet to control the CNT pulling tension to be constant. .

  The material of the choke seal is preferably an abrasion-resistant polyurethane resin having a JIS rubber hardness of 40 to 90 degrees, and the shape of the choke seal does not change even when the CNT continuous fiber thickness changes. Is preferable. Since such a choke seal can keep the contact pressure with the drawn CNT continuous fiber 401 lower, the life of the parts can be extended. In addition, even when producing lots with different thicknesses, it can be used in a wide range and the replacement frequency of the choke seal parts can be reduced.

  For example, as shown in FIG. 4, it is also preferable to rotate the elastic ring around the axis of the drawn CNT continuous fiber (hereinafter, this sealing mechanism is referred to as a rotational elastic seal). By rotating the elastic ring when pulling the CNT continuous fiber from the reactor to the atmosphere, in addition to the above effect of the elastic ring, CNT can be captured while twisting, so it is focused on the strong continuous fiber And stable production is possible. Hereinafter, with reference to FIG. 4, the details of the rotary elastic sealing mechanism that takes CNTs from the reaction furnace while sealing and twisting them will be described.

  In FIG. 4, a housing 51 is fixed to the seal box 90 with bolts. Inside the housing 51, the hollow shaft 52 is rotatably supported by a bearing 55 and is configured to rotate by a variable speed motor 56. A transparent cover 53 is also provided to prevent the gear lubrication grease from scattering. A CNT tray 93 is screwed into the upper end of the hollow shaft 52, and is sealed by an O-ring 54 so that flammable gas such as carrier gas and fine dust do not leak from the reaction chamber into the post-process chamber. An elastic ring 57 is press-fitted to the lower end of the hollow shaft 52 so as to be concentric with the hollow shaft 52 and is fixed by a hose band (not shown).

  The shape of the elastic ring 57 is the same as that of the choke seal 92A shown in FIG. 3 except that a gas introduction hole capable of adjusting the internal air pressure while rotating is provided. That is, the pressurized air supply means 92C is connected to the hollow shaft through a rotatable rotary joint 59, and after the pressurized air is guided to the hollow shaft 52, the hollow shaft 52 is connected to the hollow portion of the elastic ring 57. It is a configuration to be supplied. The seal configuration, method, and control means of the elastic ring 57 are the same as those of the choke seal described with reference to FIG. 3, and a function of twisting CNTs by adding rotation of the elastic ring is added.

  The CNTs are usually focused in a state that is not industrially useful and regular due to weak intermolecular forces in the reactor. For this reason, it is difficult to take CNTs stably from the reactor due to fluctuations in the process conditions (temperature, pressure, concentration, etc.) in the furnace and instability factors such as dirt in the furnace, and continuous production may not be continued. There is also. However, if the rotational elastic sealing means as described above is utilized, the CNTs descending to the tray can be captured while twisted and focused on continuous fibers having a strength that can pass through the process. Therefore, the above-mentioned problem can be avoided and CNT continuous fiber can be produced more stably.

  Here, the twist angle is determined by the number of rotations of the elastic ring 57 with respect to the take-up speed, but the angle when drawn out from the reactor is about 5 to 30 degrees, and further stretching, twisting, and winding in the post-process after direct connection It is desirable that the twist angle is around 45 degrees with a desired thickness.

  In addition, since hydrogen used suitably as carrier gas etc. has a possibility of combustion or explosion at 4 to 75 volume% with respect to air, in order to raise safety | security more, local suction equipment is made elastic ring 92, 92A, It is also desirable to install it on the outlet side of 57.

Labyrinth seal and gas seal FIG. 5 shows a seal box 90 provided with a labyrinth seal 61 instead of a seal by an elastic member. The labyrinth seal has a plurality of narrow portions and a plurality of wide portions with respect to the traveling direction of the CNT continuous fiber, and the gas accompanying the drawn CNT expands in the wide portion after passing through the narrow portions. This is a sealing member that reduces the gas leaked by causing a pressure drop and repeating it. The labyrinth seal has a low sealing resistance, and can be suitably used particularly for continuously taking out CNTs that are easily removed.

  The running path of the CNT continuous fiber in the labyrinth seal preferably has a mirror-finished wall surface, and sharp edges are preferably removed from the corners of the narrow portion by electrolytic polishing.

  It is preferable to increase the number of steps of the narrow portion and the wide portion according to the difference between the pressure in the reaction furnace and the atmospheric pressure, and the differential pressure between the outlet and the inlet is 5% or more with respect to the inlet pressure of the labyrinth seal 61. .

  Here, as in the case of sealing with an elastic ring, it is also desirable to install a local suction facility on the outlet side of the labyrinth seal 61 in order to further improve safety.

  In order to more reliably prevent gas and dust from leaking out, it is preferable to actively introduce gas into the widened portion of the central portion of the labyrinth seal tube 67 in the running direction of the CNT continuous fibers (gas seal). . Examples of the gas used at this time (hereinafter, this gas is referred to as a seal gas) include inert gas, water vapor, carbon dioxide gas, and the like, which are safe and have no problem even if they exist in a general working space instead of an oxidant. .

  The sealing gas is preferably supplied via the gas supply pipe 100 and may be any pressure that is higher than the pressure inside the reactor, but is 1.05 times the accompanying gas pressure in the widened portion 66 and atmospheric pressure. It is preferable that it is the above pressure. Thereby, the backflow of the atmosphere (oxygen) to the reactor can be prevented, and safer operation is ensured.

  In addition, when the thickness of the continuous fiber to be produced is constant and it is necessary to reduce the equipment cost, the labyrinth seal is not adopted, and only the gas seal using the seal tube can be used. That is, it is possible to employ a seal tube having a gas blowing hole on the inner surface and having a constant inner diameter, and prevent leakage of gas and dust by simply introducing the sealing gas through the blowing hole. In that case, since the consumption of the seal gas is proportional to the gap area between the seal tube and the continuous fiber and inversely proportional to the length of the seal tube, it is preferable to change the thickness of the seal tube according to the thickness of the continuous fiber to be produced. Furthermore, it is preferable that the inner surface of the seal tube has a Vickers hardness Hv> 400 and is mirror-finished.

  Regardless of the labyrinth seal or the gas seal, the consumption of the input gas can be reduced by using the same pressure seal mechanism described later. In FIG. 5, the tray 93 is held at the lower part of the seal box by an O-ring 54, which is an elastic material, and dust is likely to concentrate at the labyrinth entrance. Therefore, it is also preferable to prevent the diffusion of dust into the working chamber by providing a bypass passage 66 to join the gas and dust from the reactor and the introduced inert gas to the exhaust hole 99.

・ Same pressure seal
FIG. 6 shows a mode in which the same pressure sealing mechanism is provided in the sealed box.

  The same pressure sealing mechanism includes a cylinder 61A connected to the downstream side of the tray 93, a differential pressure sensor 62 that detects a pressure difference between the inside of the cylinder 61A (inside the reaction furnace) and the outside of the reaction furnace, and a gas or the like. It comprises a discharge port 301, a calculation means 64 for sending a signal to a suction pump 63 connected to the exhaust pipe 99, and the like. In such a same pressure sealing mechanism, the differential pressure sensor 62 detects the differential pressure inside and outside the reactor, and the calculation means 64 adjusts the suction capacity of the pump 63 according to the result of the differential pressure sensor 62, The operation is controlled so that the differential pressure is minimized, preferably zero. As a result, it is possible to prevent the gas in the reaction furnace from leaking into the atmosphere, and at the same time, it is possible to prevent the atmosphere outside the reaction furnace from flowing into the furnace.

  Here, it is desirable that the cylinder 61A has a labyrinth seal shape. By adopting a labyrinth seal shape, leakage of gas and dust can be prevented more reliably. In order to further improve safety, it is also desirable to install a local suction device (not shown) on the outlet side of the cylinder 61A as in the case of a seal using an elastic ring or a labyrinth seal.

  Further, similarly to the gas sealing means described above, it is also desirable to provide a gas input pipe 100 in the middle of the cylinder 61A and introduce an appropriate amount of sealing gas therefrom. By using the same pressure seal mechanism and gas seal mechanism together, it is possible to keep the differential pressure inside and outside the reactor as zero as possible compared to when the differential pressure is not adjusted, and the amount of seal gas consumed. Can be drastically reduced, and the tolerance for the production conditions of CNT continuous fibers having different thicknesses can be increased, and the frequency of component replacement when changing the type can be reduced. Furthermore, compared with a sealing means such as an elastic ring that comes into contact with the passing CNTs, the sealing resistance is low, and it is particularly effective when taking out CNT continuous fibers that are easily removed.

Liquid Seal FIG. 7 illustrates a mode in which a liquid seal mechanism is provided in a seal box. In FIG. 7, the liquid sealing mechanism includes a flow rate adjusting valve 96 that injects an appropriate amount of liquid 95 (which may be water, a lubricant, or a dispersant described later) into the tray 93, and excess liquid 95 that flows along the drawn CNT. It consists of a suction device 101 for recovery. In such a liquid seal mechanism, the liquid 95 is instilled via the flow rate adjusting valve 96, thereby closing the gap between the central hole of the tray and the CNT to be drawn out and preventing the outflow of gas, dust and the like. Can do. Such a sealing mechanism is an effective means particularly when CNT having poor orientation falls to the receiving tray 93, and by using a dispersant as the liquid 95, the orientation can be enhanced separately from the sealing effect, and the continuous fiber As well as increasing the strength when pulling out, it can also prevent the generation of pills.

  Here, the viscosity of the liquid 95 and the shape of the receiving tray 93 are selected so that the speed at which the liquid 95 and the continuous CNT fiber are combined and freely fall from the receiving tray 93 is faster than the drawing speed at the time of actual production. It is preferable to reduce the drawing resistance. Therefore, it is preferable that the receiving tray 93 opened in the funnel shape continues smoothly to the outlet of the sealed box.

  Moreover, it is preferable that the elastic member 93B is arrange | positioned in the outer periphery of the saucer 93 in order to improve a sealing performance. Furthermore, it is preferable to inject the liquid 95 below the liquid level of the liquid accumulated in the tray 93.

  The used liquid that flows out of the seal box 90 accompanying the CNT is squeezed by at least two squeezing guides 101A, and a suction device provided between the guides so as to face the running yarn. At 101, suction processing is performed.

(3) Device configuration of the CNT continuous fiber take-up unit 400 The take-up unit 400 in FIG. 1 includes, for example, an oil agent applicator 10 that applies an oil agent such as a surfactant to the CNT continuous fiber drawn from the reaction furnace 200, and a CNT continuous unit. It comprises a drawing pair roll 11 for drawing fibers, a single spindle driven ring twister 12, and a winding device such as a bobbin 13.

  In such an apparatus, when the CNT continuous fiber pulled out from the sealed box has a tensile strength that can pass through the post-process stably, the CNT continuous fiber is first subjected to a surfactant or the like by the oil applicator 10. Oil is applied. By applying the oil agent, the CNT continuous fiber can smoothly pass through the directly connected drawing, twisting, winding process and the post-process of producing the composite material including the knitting and the CNT continuous fiber.

  The CNT continuous fiber to which the oil agent is applied is then stretched to a predetermined fineness between the rollers while being fed at a constant speed by the stretched pair roll 11. The stretching means may be a combination of an apron nip roller used in a stretching false twisting machine or a nip roller system using a rubber roll, and the nip pressure is preferably more than a force that does not cause yarn slip on the roller, and the stretching ratio is, for example, 0.95 10 times. A single roll may be used as long as a CNT continuous fiber having a desired fineness can be obtained only under the production conditions of the reaction furnace, but a pair roll is desirable in order to stabilize the drawing tension and finely adjust the required fineness.

  Next, twisting is performed while ensuring the tensile strength of the CNT continuous fiber so that the twist angle is about 20 to 70 degrees, preferably 40 to 50 degrees with a single spindle drive ring twister 12 for cotton spinning, The bobbin 13 is continuously wound up. At this time, the raising / lowering range of the ring rail 14 is changed according to the required winding shape of the bobbin. In addition, a twist angle says the angle where the fiber longitudinal direction and the direction of a CNT bundle cross. Further, as the twisting and winding device, a ring twister has been proven and preferable, but the twisting device and the winding device may be installed separately.

  It is preferable to install a thread presence sensor 15 on the yarn path to the winding means such as the bobbin 13 to detect that yarn breakage or roller winding has occurred due to some abnormality. When an abnormality occurs, it is preferable to suck and temporarily store CNT at the outlet of the sealed box so as to ensure a steady operation of the generation process in the reaction furnace.

  On the other hand, when the CNT continuous fiber drawn out from the sealed box does not have a tensile strength that can pass through the post-process stably, it is desirable to provide a twist winding device as shown in FIG. .

  The structure of the twist winding apparatus 500 will be described. A turntable 503 rotatably supported by the base 502 is rotated by a twisting variable speed motor M1. A bobbin holder 504 supported so as to reciprocate with a screw with respect to the turntable 503 is driven by a forward / reverse and variable speed motor M2. The bobbin holder 504 holds the bobbin 505 so as to be detachable, and the rotation speed is controlled by the control device 506 so that the rotational speed is gradually decreased as the winding diameter is increased by the variable speed motor M3 so that the winding speed becomes constant. Here, as the winding diameter, a value measured by a non-contact winding thickness meter 508 attached in the vicinity of the yarn path center guide 507 provided on the axis of the motor M1 is used. Further, the winding shape can be changed by controlling the traverse width of the variable speed motor M2 in accordance with the winding diameter. Further, the power and signal information of each motor and sensor on the turntable 503 are connected to the control device 506 through a slip ring 509 provided in the base 502.

  Then, the CNT continuous fiber 401 is twisted by the motor M1 by installing the rotation axis of the motor M1 of the twist winding unit 500 and the axis of the outlet 300 of the seal box 90 substantially concentrically. At this time, the twist is retroactive to the upstream side of the outlet 300 having a sealing function, and the CNT descending to the receiving tray 93 has not only the intermolecular force but also the tensile strength enhanced by the twisting effect. It is pulled out and wound on a bobbin 505. In addition, it applies to the aspect mentioned above about application | coating of an oil agent, detection of thread breakage, etc.

2) Method for Producing Carbon Nanotube Continuous Fiber In the present invention, a carbon source, a catalyst, and a carrier gas are introduced into a reaction furnace, and carbon nanotubes are continuously generated by a fluidized gas phase CVD method. Gas and dust are separated from the carbon nanotubes and discharged, and the produced carbon nanotubes are continuously drawn out to the air atmosphere to obtain continuous carbon nanotube fibers. Below, the method to produce | generate a CNT continuous fiber with the apparatus shown in FIG. 1 FIG. 2 is demonstrated exemplarily.

  First, a carbon source to be introduced into the reaction furnace is mixed with a catalyst and an additive (details will be described later) in advance to prepare a solution 4. In addition, by using a plurality of types of carbon sources, it is possible to produce ultrafine single-walled CNTs with high purity.

  Before starting the operation, the transparent door 97 of the seal box 90 is opened, and a brush-like thread hook 91 (details will be described later) as shown in FIGS. The thread hook is prepared so that the CNT descending by the hook 91 can be captured.

  In this state, the temperature of the reaction tube 2 is maintained at 600 to 1200 ° C., and the mixed solution 4 of the carbon source, the catalyst, and the additive is fed by the microfeeder 5 and the reaction tube is sprayed together with the carrier gas 7 by the spray nozzle 3. Spray into 2. At this time, the carrier gas 7 is measured by the flow meter 6 and sprayed from the outer tube of the spray nozzle 3 which is a double tube, and serves to make the mixed solution 4 from the inner tube into a mist. As a result, the carbon source injected into the reaction tube 2 is gasified and grows from a fine particle catalyst mixed in a trace amount to become a CNT single fiber. The CNT monofilaments move together with the carrier gas in the gas space and gather together by intermolecular force to grow into a bundle of CNTs, and eventually adhere to the wall surface of the reaction tube 2 and further around the tray 93 and the thread hook. Fall down. After confirming that the CNTs descending in a bundle in this manner are in close contact with the yarn hook 91, the yarn hook 91 is captured so as to capture the bundle of CNTs in the manner of making cotton candy so as not to escape. Pull out from the seal box 90 while twisting, and take out the CNT (CNT continuous fiber) in a state where the bundle is continuously connected. The twist angle at this time is preferably about 10 degrees or more, and it is preferable to give a large amount of twist in advance in consideration of the speed of drawing out from the reactor and the threading time in the subsequent process.

  The CNT continuous fiber taken out from the sealed box 90 is then threaded around the drawn pair roll 11 and the ring twister 12 at a speed suitable for the production speed determined by the amount of input material and wound around the bobbin 13. After winding the drawn CNT around the bobbin, the CNT can be continuously pulled out from the reaction furnace 200 by continuously rotating the bobbin, and continuous CNT fibers can be obtained continuously.

  Here, when pulling out CNT from the reaction furnace 200, it is necessary to discharge dust, carrier gas, unreacted gas, and the like generated from a substance input as a carbon source, separately from the carbon nanotubes and discharged. is there. Therefore, dust and gas are discharged from the discharge port 301 provided separately from the CNT outlet 300, and discharged to the outside through the exhaust pipe 99, the bubbler 98, and the dust fine filter 102. The bubbler 98 prevents the backflow of air to the reaction furnace.

  Further, when the carbon nanotubes are pulled out from the reaction furnace 200 to the atmosphere, it is preferable to keep the reaction furnace 200 and the carbon nanotubes airtight by the sealing mechanism as described above. The operational effects of each seal mechanism are as described above. However, when adopting the rotational elastic seal system as shown in FIG. 4, when the CNT is supplemented by the thread hook 91, the motor 56 is rotated, It is preferable to take out the CNT from the sealed box and thread it to the next step while twisting the CNT in the sealed box retroactively. The required number of rotations can be set at a variable speed, and the twist angle is preferably 10 degrees or more, and it is preferable that the twist angle of the performance matching required in the subsequent twisting process is additionally twisted.

  When the bobbin reaches a desired size, the continuously produced yarn is temporarily deposited in a suction gun and the new bobbin is threaded.

  In addition, the CNT continuous fiber in the present invention may contain other components (for example, catalyst fine particles and fullerene that did not grow on CNT) as long as the CNT can be maintained in a connected state. It is preferable that 70% by weight or more is composed of CNT.

3) Description of thread hook FIG. 9 shows a schematic diagram of the thread hook. The thread hook 91 is for first capturing the generated CNT from the sealed box 90 that is airtightly engaged below the reaction tube 2, pulling it out, and threading it in the winding process. The thread hook 91 has a core wire 91B at the tip of the handle portion 91A, and a plurality of small-diameter wires 91C protrude from the core wire 91B. By catching the CNT generated on the small diameter wire 91C, the CNT can be captured effectively.

  It is preferable that the small-diameter wire 91C is sprayed with a fine particle ceramic to form a fine sharp protrusion on the surface so that CNTs can be captured more reliably. However, it is more preferable that the minute protrusions are not on the outer peripheral portion that comes into contact with the seal portion when the small-diameter wire 91C passes through the seal portion.

  It is also preferable that at least the surface of the small diameter wire 91C is made of an insulating material. When composed of an insulating material, the surface can be charged by the action of friction, corona discharge, etc. As a result, an induced charge is generated in the CNT, which is a conductor, and the CNT is adsorbed to the small diameter wire 91C by electrostatic force. It can be made easy. At this time, the core wire 91B and the handle portion 91A are made of a conductor, and if this is grounded, a part of the bundle of CNTs can touch the core wire 91B, whereby the entire bundle of CNTs can be grounded. The induction of the charge of the CNT corresponding to the charge of the small diameter wire 91C is ensured, which is more preferable.

  In the case of using the method of attracting CNTs by the electric charge attached to the surface of the insulating material in this way, the small diameter wire 91C is not necessarily required if there is sufficient ability to capture CNTs, and the conductor 91B is around the conductor core wire 91B. Alternatively, an insulating material may be used leaving the tip.

  Furthermore, it is also preferable to incorporate a battery and a motor that give rotation corresponding to the production speed into the knob 94 of the thread hook 91 to improve workability.

4) Material to be charged into reaction furnace (1) Carbon source It is preferable to use a hydrocarbon as the carbon source, and the hydrocarbon is preferably a liquid in which a catalyst and a reaction accelerator described later are dissolved. Examples of such hydrocarbons include aromatic hydrocarbons, alicyclic hydrocarbons, long-chain aliphatic hydrocarbons, and benzene and toluene are particularly preferably used.

On the other hand, a plurality of types of carbon sources can be used so that CNTs having desired characteristics can be easily generated. When using multiple types of carbon sources (in addition to the above-mentioned liquid carbon sources, for example, ethylene as another carbon source), although not shown, a measuring line and input that can be set independently of the main carbon source described above are used. Prepare a carrier gas line for.
(2) Catalyst The catalyst is not particularly limited by the type of metal or the difference in form thereof, but a transition metal compound or transition metal ultrafine particles (for example, metal clusters of about 1 nm) are preferably used. The transition metal compound can generate transition metal particles as a catalyst by being decomposed in a reaction tube.
These transition metal compounds and transition metal atoms are preferably supplied in a gaseous state to a reaction region maintained at a temperature of 800 to 1200 ° C. in the reaction tube, and before the temperature is raised to a predetermined reaction temperature. Furthermore, those that can be completely vaporized are preferred.

  Examples of the transition metal atom include iron, nickel, cobalt, scandium, titanium, vanadium, chromium, manganese, and the like, among which iron, nickel, and cobalt are more preferable.

  As a transition metal compound, an organic transition metal compound, an inorganic transition metal compound, etc. can be mentioned, for example. Examples of the organic transition metal compound include ferrocene, nickelocene, cobaltcene, iron carbonyl, iron acetylacetonate, iron oleate, and the like, and ferrocene is more preferable. Examples of the inorganic transition metal compound include iron chloride.

(3) Carrier gas Hydrogen is particularly preferable as a carrier gas that serves as a diluent, but inert gas or carbon dioxide gas may be used if production costs are not considered. When the carrier gas is hydrogen, the input weight is preferably about 10 times that of the carbon source, but is not limited thereto.

(4) Desirable additives In the production method of the present invention, it is preferable to further add a sulfur compound. The sulfur compound interacts with a transition metal atom suitable as a catalyst and has an action of promoting the production of single-walled CNTs. Examples of such sulfur compounds include organic sulfur compounds and inorganic sulfur compounds. Examples of the organic sulfur compound include sulfur-containing heterocyclic compounds such as thianaphthene, benzothiophene, and thiophene, and thiophene is more preferable. Examples of inorganic sulfur compounds include sulfur sulfide.

5) Dispersant As described above, in the liquid seal, the gap between the central hole of the saucer and the CNT drawn out is closed to prevent outflow of gas such as carrier gas or dust, and the like through the flow regulating valve 96. It is also preferred to instill the agent. CNTs are preferred to improve the orientation in order to produce continuous fibers with higher strength without pulling out from the reactor 200 during drawing, stretching, and winding, but due to the action of the dispersant, The coefficient of friction at the surface is lowered, and they are likely to be displaced from each other and oriented easily. As a result, it becomes easy to pull out from the reaction furnace, and the thickness unevenness is reduced, so that it is easy to twist in the subsequent process, and the resulting continuous fiber has suppressed generation of pills. Further, since the yarn does not come off or is not cut off in the middle, process stability is also improved.

  As the dispersant, a material known as a CNT dispersant can be appropriately selected and used. For example, alkylamine salts, quaternary ammonium salts, alkylbenzene sulfonates, sulfonic acid-containing polymers, fructose, sucrose, polypeptides, polysaccharides such as cellulose, hemicellulose, amylose, and amylopectin and their derivatives are used. However, since many of the above compounds exhibit insulating properties, it is preferable to add as little as possible to the CNT continuous fiber, specifically 10 wt% or less.

  Furthermore, a compound having a developed conjugated system can also be used as a dispersant. For example, there are conjugated polymers such as polythiophene, polythioenylene vinylene, polyphenylene vinylene, poly-p-phenylene, polypyrrole, polyaniline, polyacetylene, polycarbazole, polyfluorene, polyfuran, and polyindole polymers. These polymers may be a copolymer of a plurality of types, and a polymer in which a substituent such as an alkyl chain is introduced into a side chain or the like in order to impart solubility to a solvent is also preferably used.

  Other compounds that have developed conjugated systems include polyheteroaryls containing nitrogen-containing aromatic rings such as pyridine, quinoline, phenanthroline, oxazole, oxadiazole, anthracene, pyrene, naphthacene, pentacene, hexacene, rubrene Condensed polycyclic aromatic compounds such as furan, thiophene, benzothiophene, dibenzofuran, pyridine, quinoline, phenanthroline, oxazole, oxadiazole, etc., 4,4′-bis (N- (3 Aromatic methyl derivatives represented by -methylphenyl) -N-phenylamino) biphenyl, biscarbazole derivatives such as bis (N-allylcarbazole) or bis (N-alkylcarbazole), pyrazoline derivatives, stilbene compounds, hydrazone compounds Conversion Products, metal phthalocyanines such as copper phthalocyanine, metal porphyrins such as copper porphyrin, distyrylbenzene derivatives, aminostyryl derivatives, aromatic acetylene derivatives, naphthalene-1,4,5,8-tetracarboxylic acid diimide, perylene-3 , 4,9,10-tetracarboxylic acid diimides, condensed ring tetracarboxylic acid diimides, merocyanines, phenoxazines, organic dyes such as rhodamine, and porphyrin compounds.

  An ionic liquid can also be used. Further, when using a compound with a conjugated system or an ionic liquid, these compounds are compounds that exhibit some conductivity, so the amount added to the CNT continuous fiber is not particularly limited, but may be equal or less. More preferred.

  The above materials can also be used by dissolving in a solvent. In that case, a solvent having a boiling point of 50 to 250 ° C. is preferably used.

6) Oil agent In the present invention, as described above, the reaction furnace 200 is used to smoothly advance the stretching, twisting, winding process and the post-process of producing the composite material including the knitting and the CNT yarn, which are directly connected to the CNT generation process. It is desirable to apply an oil agent such as a surfactant to the CNT continuous fiber drawn from the surface.

  As the type of oil agent, those known in the textile industry can be used. For example, refined lubricant, surfactant, mineral oil, nonionic activator, anionic activator, cationic activator, esterified oil, phosphate ester salt, paraffin wax, polyhydric phenol resin, amphoteric activator, silicone oil, Examples thereof include alkylamides, aminosilicones, and urethane compounds.

  As described above, when the CNT is pulled out from the reactor while being liquid-sealed with a dispersant, there is a possibility that inconveniences such as uneven adhesion may occur in the oil agent application method as described above. It is preferable that the same effect is expressed with the wax used in the cotton spinning industry. In the case of using a wax, it is sufficient to use a columnar wax that is rotatably supported and run while contacting continuous fibers with the end face.

  According to the present invention, CNTs are generated in a reaction furnace, and CNTs are extracted by separating flammable carrier gas and other fine dust that is considered harmful to the human body. -CNT continuous fibers as industrial materials with high conductivity can be mass-produced efficiently and inexpensively while ensuring safety. Such a CNT continuous fiber can be applied to, for example, lightweight conductive wires (lightweight motors, generators), lightweight conductive cables (power transmission lines, deep sea cables, etc.).

It is the schematic of the manufacturing apparatus of the CNT continuous fiber which shows one Embodiment of this invention. It is sectional drawing of the sealing mechanism by an elastic member. It is sectional drawing of the sealing mechanism which employ | adopted the chalk seal. It is sectional drawing of the seal mechanism which employ | adopted the rotation elastic seal. It is sectional drawing of the seal mechanism which employ | adopted the labyrinth seal. It is sectional drawing of the seal mechanism which employ | adopted the same pressure seal. It is sectional drawing of the sealing mechanism which employ | adopted the liquid seal. It is the schematic of a twist winding apparatus. It is the schematic of a thread hook.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric furnace 2 Reaction tube 3 Spray nozzle 4 Mixed solution 5 Micro feeder 6 Carrier gas flowmeter 7 Carrier gas 10 Oil supply device 11 Stretched pair roll 12 Ring twister 13 Bobbin 14 Ring rail 15 Sensor with thread 51 Housing 52 Hollow shaft 53 Transparent cover 54 O-ring 55 Bearing 56 Variable speed motor 57 Elastic seal 58 Pipe 59 Rotary joint 61 Labyrinth seal 61A Cylinder 62 Differential pressure gauge 63 Suction pump 64 Arithmetic means 66 Bypass passage 67 Labyrinth seal pipe 90 Seal box 91 Thread hook 92 Elastic ring 92A Choke Seal 92B Air pressure precision adjustment mechanism 92C Pressurized air supply means 93 Receptacle 93B Elastic member 94 Knob 95 Liquid (water, lubricant or dispersant)
96 Flow control valve 97 Transparent door 98 Bubbler 99 Exhaust pipe 100 Gas input pipe 101 Suction apparatus 101A Ironing guide 102 Fine dust filter 192, 192A Outer annular part 193, 193A Inner annular part 194, 194A Cavity 200 Reactor 300 Drawer 301 Discharge port 400 Carbon nanotube continuous fiber take-up section 401 Carbon nanotube continuous fiber 500 Twisted winding device 502 Base 503 Turntable 504 Bobbin holder 505 Bobbin 506 Controller 507 Thread path center guide 508 Non-contact thickness gauge 509 Slip ring

Claims (15)

A carbon source, a catalyst, and a carrier gas are charged into the reaction furnace, and carbon nanotubes are continuously produced by a fluidized gas phase CVD method to obtain continuous carbon nanotube fibers. A method for producing a continuous carbon nanotube fiber, wherein the carbon nanotube is separated and discharged, and the produced carbon nanotube is drawn out to an air atmosphere to obtain a continuous carbon nanotube fiber. 2. The method for producing continuous carbon nanotube fibers according to claim 1, wherein the carbon nanotube is kept airtight between the reaction furnace and the carbon nanotube when the carbon nanotube is drawn out from the reaction furnace to the atmosphere. The method for producing a continuous carbon nanotube fiber according to claim 1 or 2, wherein the carbon nanotube is twisted when the carbon nanotube is drawn out from the reaction furnace to an air atmosphere. The manufacturing method of the carbon nanotube continuous fiber in any one of Claims 1-3 which apply | coats a liquid when drawing out the said carbon nanotube from the said reaction furnace to an air atmosphere. The carbon nanotube continuous fiber is continuously wound up, and at least one treatment of applying an oil agent, stretching, and twisting is performed on the carbon nanotube continuous fiber until the carbon nanotube continuous fiber is drawn out from the reaction furnace and wound up. Item 5. A method for producing a carbon nanotube continuous fiber according to any one of Items 1 to 4. It has a reaction furnace that continuously generates carbon nanotubes from a carbon source, a catalyst, and a carrier gas by a fluidized gas phase CVD method, and the reaction furnace has a gas and dust discharge port in the lower part, and the generated carbon. An apparatus for producing continuous carbon nanotube fibers, comprising an outlet for drawing out the nanotubes as continuous fibers. The carbon nanotube continuous fiber manufacturing apparatus according to claim 6, wherein the drawing outlet has a sealing unit for keeping an airtight space between the drawing outlet and the carbon nanotube when the carbon nanotube is drawn out. The apparatus for producing a continuous carbon nanotube fiber according to claim 7, wherein the sealing means is an elastic member that comes into contact with the carbon nanotube when the carbon nanotube is pulled out. The apparatus for producing a continuous carbon nanotube fiber according to claim 8, wherein the elastic member is a choke seal. The apparatus for producing a continuous carbon nanotube fiber according to claim 8 or 9, comprising a mechanism for rotating the elastic member around an axis of the drawn continuous fiber. The carbon nanotube continuous fiber manufacturing apparatus according to claim 7, wherein the sealing means is a labyrinth sealing means. The apparatus for producing continuous carbon nanotube fibers according to claim 7, wherein the sealing means has a mechanism for supplying a gas having a pressure higher than that inside the reaction furnace to the outlet. A suction pump is connected to the discharge port, and the sealing means detects a pressure difference between the inside and outside of the reactor, and a control means adjusts the operating capacity of the suction pump according to the sensor. The manufacturing apparatus of the carbon nanotube continuous fiber in any one of Claims 6-12 which has these. The carbon nanotube continuous fiber production according to claim 7, wherein the sealing means is a liquid sealing means for supplying a liquid to the inside of the outlet and maintaining airtightness between the liquid and the continuous fiber drawn. apparatus. The carbon nanotube continuous fiber manufactured with the method in any one of Claims 1-5, or the apparatus in any one of Claims 6-14.

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