KR20170011834A

KR20170011834A - Apparatus for preparing carbon nanotube aggregate and process for preparing carbon nanotube aggregate using same

Info

Publication number: KR20170011834A
Application number: KR1020150105175A
Authority: KR
Inventors: 김지은; 이경무; 이영호; 김주한; 최용진; 오유진; 송동수
Original assignee: 주식회사 엘지화학
Priority date: 2015-07-24
Filing date: 2015-07-24
Publication date: 2017-02-02
Also published as: KR102030773B1

Abstract

The present invention relates to a production apparatus of a carbon nanotube aggregate, where an empty space inside a CNT aggregate is reduced, and a production method of a carbon nanotube aggregate using the same. The production apparatus of a carbon nanotube aggregate comprises: a columnar reactor; an inlet hole; a heating means; and a discharge hole.

Description

Technical Field [0001] The present invention relates to an apparatus for manufacturing a carbon nanotube aggregate and a method for manufacturing the carbon nanotube aggregate using the carbon nanotube aggregate,

The present invention relates to an apparatus for producing a carbon nanotube aggregate and a method for producing the carbon nanotube aggregate using the same.

Carbon nanotubes (CNTs), which are a kind of carbon isotopes, have a diameter of several to several tens of nanometers and are several hundreds of micrometers to several millimeters long. Since their report in the journal Nature in 1991 by Dr. Iijima, , Physical properties and high aspect ratio have been studied in various fields. The inherent properties of these carbon nanotubes are due to the sp2 bond of carbon, stronger than iron, lighter than aluminum, and exhibit electrical conductivity similar to that of metals. According to the number of nanotubes, single-wall carbon nanotubes (SWNTs), double-wall carbon nanotubes (DWNTs), multi-walled carbon nanotubes (Multi- Wall carbon nanotube (MWNT), and can be divided into zigzag, armchair, and chiral structures depending on the asymmetry / chirality.

Meanwhile, carbon nanotubes (CNTs) have attracted attention as high-strength and lightweight materials, and various methods for manufacturing members using the carbon nanotubes have been tried.

Until now, members using CNTs are manufactured in the form of CNT fibers or CNT mats. In order to manufacture such members, a cylindrical reactor having an aspect ratio of 1 in the reactor is conventionally used. In this method, a cylindrical CNT aggregate with an empty interior is formed in the reactor.

In the empty space inside the CNT aggregate, there is a problem that CNT can not form an aggregate because the flow rate of the spinning solution is fast and is discharged together with the carrier gas, thereby causing a decrease in the yield.

Korean Patent No. 10-1286751

In the conventional apparatus for manufacturing a carbon nanotube (CNT) aggregate, there is a problem that the CNT aggregate having an empty interior is produced with an aspect ratio of 1 in cross section of the main body of the reactor, and the yield is lowered.

Accordingly, it is an object of the present invention to provide an apparatus for producing a carbon nanotube aggregate having an aspect ratio exceeding 1. That is, it is an object of the present invention to provide a carbon nanotube aggregate in which the space of the CNT aggregate film is reduced and the void space inside the CNT aggregate is reduced .

In order to accomplish the above object, the present invention provides a reactor comprising a columnar reactor having a reaction zone; An inlet for injecting a spinning material and carrier gas into the reaction zone of the body; Heating means for heating the reaction region; And a discharge port installed at a lower end of the main body to discharge the carbon nanotube aggregate, wherein the horizontal cross sectional aspect ratio of the columnar reactor is more than 1 and less than 100. Preferably, the aspect ratio of the horizontal cross section of the columnar reactor may be between 2 and 20.

According to a preferred embodiment of the present invention, the horizontal cross section of the columnar reactor may be elliptical or polygonal, and the columnar reactor may be a slit column reactor. The carbon nanotube aggregate discharged from the outlet may be a carbon nanotube fiber or a carbon nanotube mat.

The present invention can provide an apparatus for manufacturing a carbon nanotube aggregate in which the void space inside the CNT aggregate is reduced. In this way, CNTs generated in the center portion are not lost, and aggregates can be formed to increase the yield. It is also easy to manufacture carbon nanotube mat, which is a large-scale carbon nanotube aggregate.

1 is a schematic horizontal sectional view of a reactor and a reactor of a conventional apparatus for producing a carbon nanotube aggregate.
2 shows an apparatus for producing a carbon nanotube aggregate according to an embodiment of the present invention.
3 is a horizontal cross-sectional schematic diagram of a reactor and a reactor of an apparatus for producing a carbon nanotube aggregate according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. The following detailed description is merely an example of the present invention, and therefore, the present invention is not limited thereto.

In the drawings, like reference numerals are used for similar elements.

The term "and / or" includes any one or a combination of the plurality of listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it is to be understood that other elements may be directly connected or connected, or intervening elements may be present.

The singular expressions include plural expressions unless otherwise specified.

The terms "comprises", "having", or "having" mean that there is a feature, a value, a step, an operation, an element, a component or a combination thereof described in the specification, Does not exclude the possibility that a number, a step, an operation, an element, a component, or a combination thereof may be present or added.

In the present specification, the term "carbon nanotube aggregate" refers to both carbon nanotubes grown in an aggregate form or formed by fusing a plurality of carbon nanotubes in an aggregate form.

Techniques for producing carbon nanotube aggregates include solution spinning, array spinning, aerogel spinning, and / or twisting or rolling of films. The present invention follows a process of directly radiating a carbon nanotube aggregate or ribbon from a carbon nanotube aerogel formed immediately after the introduction of a spinning material in a reactor by using chemical vapor deposition (CVD).

In the direct spinning, carbon nanotubes are synthesized in a heating furnace by injecting carbon nanotubes at a constant rate in a vertical furnace together with a carrier gas by adding a catalyst to the carbon nanotubes, and pure carbon nanotubes Carbon nanotube aggregates are continuously produced.

The catalyst precursor of the present invention is a substance which is not contained in the catalyst cycle but is changed into an active catalyst (or produces an active catalyst) in the course of the catalytic reaction, and in the present invention, the catalyst precursor forms a catalyst Then, CNT is synthesized.

As shown in Fig. 1, the cross-sectional aspect ratio (b / a) of the reactor body is 1 in the prior art carbon nanotube (CNT) aggregate production apparatus. Therefore, there is a problem that a CNT aggregate having an empty interior is produced.

Accordingly, the present inventors have made an effort to solve the above problems, and have found that, when the cross-sectional aspect ratio of the reactor of the carbon nanotube aggregate production apparatus exceeds 1, this can be solved.

A columnar reactor having a reaction zone; An inlet for injecting a spinning material and carrier gas into the reaction zone of the body; Heating means for heating the reaction region; And a discharge port installed at a lower end of the main body to discharge the carbon nanotube aggregate, wherein the horizontal cross sectional aspect ratio of the columnar reactor is more than 1 and less than 100. In the present invention, the aspect ratio means the ratio of width to length of the horizontal cross section, and the ratio value (b / a) of the long length 2b to the short width 2a among the width and height.

Hereinafter, the present invention will be described more specifically with reference to the drawings.

2 shows an apparatus for producing a carbon nanotube aggregate according to an embodiment of the present invention. A columnar high temperature reactor main body 11 having a reaction region; An inlet 10a for injecting the spinning material into the reaction zone of the body and an inlet 10b for injecting the carrier gas; Heating means (12) for heating the reaction zone; And a discharge port (13) installed at a lower end of the main body to discharge the aggregate of carbon nanotubes, wherein an aspect ratio of a cross section of the main body of the columnar reactor is more than 1 and less than 100. According to a preferred embodiment of the present invention, the horizontal cross-sectional aspect ratio of the columnar reactor body may be 2 or more and 20 or less. If the ratio exceeds 100, the internal carrier gas may not flow smoothly, which may cause problems in the production of CNT aggregates. Therefore, the above range is preferable. Since the cross section of the reactor of the present invention is a square, 1 or less is not necessary to be discussed. That is, the aspect ratio of 0.5 is the same as the aspect ratio of 2.

The inlets 10a and 10b may include a spray nozzle for injecting the spinning material and a dispersing plate for injecting the carrier gas. The inlet may be an injection nozzle, but is not limited thereto.

In the apparatus, the inlet (10) may further include a spinning material supply unit for supplying a spinning material to the reactor body (11), and a carrier gas supply unit for supplying the carrier gas. In addition, the spinning material supply unit may include a mixer for dispersing the catalyst precursor in the gaseous or liquid carbon compound, and a transport pump for supplying the spinning material formed in the mixer to the spinneret spraying nozzle. The carrier gas introduced from the inlet may be introduced into the reaction zone at a linear velocity so as to form laminar flow, and a dispersion plate may be used for this purpose. The carrier gas may be introduced into the reactor body 11 through the inlets 10a and 10b from a carrier gas supply unit having a gas tank and flow control means. The flow regulating means regulates the gas flow rate so that the carrier gas is supplied at a linear velocity at which laminar flow can be formed.

Specifically, the spinning material and the carrier gas flow into the reactor through the inlet. And, when the catalyst precursor contained in the spinning material is supplied to the reactor, it is reduced in a high temperature zone to form a catalyst. The formed catalyst flows from the upper end to the lower end of the reactor to form carbon nanotubes, and grows or fuses to form the carbon nanotube aggregates 15. At this time, the carbon nanotube aggregate is generated by the flow inside the reactor while maintaining a constant distance from the inner wall of the reactor, which is shown in FIG.

Meanwhile, conventionally, when the aspect ratio of the reactor was 1, and the diameter of the reactor was A, the CNT aggregate maintained a minimum distance of 0.185 * A from the inner wall of the reactor. Therefore, a hollow space is formed inside the carbon nanotube aggregate to be produced, thereby causing a problem that the yield is lowered. The constant of 0.185 is conventionally used as a constant experimentally obtained in a flow comprising spherical particles.

However, in the present invention, as shown in Fig. 3, the cross-sectional aspect ratio of the reactor is made larger than 1, so that the interval between the CNT aggregate film and the cross-section of the cross section of the transverse cross- 3 (a) is an elliptic slit column reactor, and FIG. 4 (b) is a rectangular slit column reactor. Accordingly, the void space inside the CNT aggregate can be reduced, and the CNT generated at the center can be lost without forming the aggregate, thereby increasing the yield. In addition to this, it is also easy to manufacture a large-area CNT mat.

According to a preferred embodiment of the present invention, the columnar reactor may be a slit column reactor. And the horizontal cross section of the columnar reactor may be elliptical or polygonal. The polygon is an n-prism having an integer of 3 < n, and preferably an n-prism having an integer of 3 < n < Most preferably a square, but is not limited thereto. Fig. 3 (a) shows that the horizontal section of the reactor is elliptical, and Fig. 3 (b) shows that the horizontal section is square.

Then, the CNT-grown catalyst particles move to the lower end, and the formed CNT aggregate is wound on the winding means 14 through the discharge port. The carrier gas and / or unreacted radiation material is vented through the vent. Then, the catalyst is discharged together with the CNT because the CNT grows, and the unreacted catalyst can also be buried in the CNT to be discharged. The exhaust port may be provided between the heating means and the exhaust port or at a rear end of the CNT aggregate exhaust port.

In the present invention, the heating means 12 may be a heating furnace surrounding the reactor main body, and the reaction region may be heated to 1,000 to 3,000 캜. The high temperature region of the reactor may preferably maintain a temperature of 1,000 to 2,000 DEG C, 1,000 to 1,500 DEG C or 1,000 to 1,300 DEG C, and more preferably 1,100 to 1,200 DEG C. [ The temperature in the high temperature region of the reactor influences the rate at which carbon is diffused into the catalyst to control the growth rate of the carbon nanotube. When synthesizing carbon nanotubes by chemical vapor deposition, generally, the higher the synthesis temperature, the higher the crystallinity and strength as the growth rate of carbon nanotubes increases.

According to a preferred embodiment of the present invention, the carbon nanotube aggregate discharge port 13 may include winding means 14 for collecting and collecting the carbon nanotube aggregate discharged from the lower end of the columnar reactor main body. That is, when the spinning material is continuously injected, the carbon nanotubes synthesized inside the reaction region collect the aggregate at the center of the reactor body and the heating furnace while forming a continuous aggregate into a cylindrical shape, . According to a preferred embodiment of the present invention, the carbon nanotube aggregate may be a carbon nanotube fiber or a carbon nanotube mat. 2, the carbon nanotube aggregate discharged to the winding means is a carbon nanotube fiber, and FIG. 2 (b) shows a carbon nanotube aggregate discharged from the winding means is a carbon nano tube It is a tube mat. The carbon nanotube fibers are produced by shrinking the carbon nanotube aggregate in a reverse radial direction without voids therein. And the carbon nanotube mat is obtained by compressing the carbon nanotube aggregate in one direction, for example, in a downward direction.

The winding means 14 may include at least one selected from a spindle, a reel, a drum, a bobbin, and a conveyor. However, the present invention is not limited thereto, and any means capable of stably winding the discharged carbon nanotube aggregate can be used. The winding temperature and velocity affect the orientation of the carbon nanotubes in the aggregate in the axial direction of the aggregate, thereby determining the thermal, electrical, and physical properties of the carbon nanotube aggregate. Preferably, it can be wound at a temperature of 15 to 120 DEG C in the range of 5 to 100 rpm.

In addition, the carbon nanotube aggregate outlet 13 is preferably provided with an inert gas injection port to form an inert gas curtain surrounding the continuous aggregate of carbon nanotubes. The outlet 13 may include an outlet for discharging the generated carbon nanotube aggregate and an exhaust line for discharging the carrier gas.

On the other hand, the spinning material may include a carbon compound in a gas form as well as a liquid form. The liquid or gaseous carbon compound is synthesized into carbon nanotubes by diffusing as a carbon source as a catalyst and is used in consideration of molecular weight distribution, concentration, viscosity, surface tension, dielectric constant and / or properties of the solvent to be used.

According to a preferred embodiment of the present invention, the liquid or gaseous carbon compound is selected from the group consisting of methane, ethylene, acetylene, methyl acetylene, vinyl acetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetic acid, And one or more selected from the group consisting of polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane, hexane, benzene, carbon tetrachloride and pentane. Specifically, the liquid carbon compound may be at least one selected from the group consisting of ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetate, diethyl ether, polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran (THF) DMF), dichloromethane, hexane, benzene, carbon tetrachloride, and pentane. (C ₂ H ₅ OH), xylene (C ₈ H ₁₀ ), diethyl ether [(C ₂ H ₅ ) ₂ _O ], polyethylene glycol [(CH ₂ -CH ₂ -O) ₉ ] 1-propanol _{(CH 3 CH 2 CH 2 OH} ), acetone (CH ₃ OCH _3), ethyl formate (CH ₃ CH ₂ COOH), benzene (C ₆ H _6), hexane (C ₆ H ₁₄₎ and mesitylene [C ₆ H ₃ (CH ₃ ) ₃ ]. The gas-phase carbon compound may include at least one selected from the group consisting of methane, ethylene, acetylene, methyl acetylene, and vinyl acetylene.

According to a preferred embodiment of the present invention, the spinning material may be a catalyst precursor dispersed in a liquid or gaseous carbon compound. The spinning material may be mixed with 0.5 to 5 wt%, preferably 1 to 5 wt%, or 1.5 to 4 wt% of the catalyst precursor to the liquid or gaseous carbon compound. If an excess catalyst precursor is used in comparison with the liquid or gaseous carbon compound of the spinning material, the catalyst acts as an impurity and it is difficult to obtain a high purity carbon nanotube aggregate. It may also be a factor that hinders the thermal, electrical and / or physical properties of the carbon nanotube aggregate. In the present invention, the catalyst precursor may include at least one selected from the group consisting of metallocene including ferrocene, iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium and oxides thereof, no. The catalyst precursor may also be in the form of nanoparticles. And preferably in a metallocene form such as ferrocene, which is a compound containing iron, nickel, cobalt and the like; Iron such as iron chloride (FeCl ₂ ); cobalt; And a nickel atom may be used as the catalyst precursor.

According to a preferred embodiment of the present invention, the spinning material may further include a catalytic activator. Generally, carbon nanotubes are synthesized by diffusion of carbon into the catalyst in the molten state of the catalyst, followed by precipitation of the carbon nanotubes. The catalyst activator is used as a promoter in the synthesis of carbon nanotubes to increase the carbon diffusion rate, Thereby synthesizing carbon nanotubes. As the catalytic activator, thiophene (C ₄ H ₄ S) may be used. Thiophene reduces the melting point of the catalyst and removes the amorphous carbon, allowing synthesis of high purity carbon nanotubes at low temperatures. The content of the catalytic activator may also affect the structure of the carbon nanotubes. For example, when 1 to 5% by weight of thiophene is mixed with ethanol as the carbon compound, a multiwalled carbon nanotube aggregate is obtained And a single walled carbon nanotube aggregate can be obtained when ethanol is mixed with thiophene in an amount of 0.5% by weight or less. According to a preferred embodiment of the present invention, the catalyst precursor and the catalytic activator may be liquid in the liquid carbon compound, and may be vapor in the vapor carbon compound. Therefore, the liquid carbon compound can be injected by dissolving the catalyst precursor or the catalytic activator, and vaporized into the gas-phase carbon compound to be injected into the gas form.

In the present invention, the carrier gas injected into the reaction zone of the reactor body 11 may be injected at a linear velocity of 0.5 to 50 cm / min, preferably 0.5 to 40 cm / min or 0.5 to 30 cm / min or 0.5 to 20 cm / min, or 1 to 10 cm / min. The carrier gas injection rate may vary depending on the type of carrier gas, the size of the reactor and / or the type of catalyst as described above.

In the present invention, the carrier gas regulates the amount of carbon nanotubes to be injected into the reaction zone by diluting the carbon nanotubes, and reacts with the generated amorphous carbon or excess impurities to purify the carbon nanotube aggregates . The carrier gas may be a hydrocarbon-based gas, an inert gas, a reducing gas, or a mixed gas thereof. The inert gas, for example argon (Ar) may be a gas, a nitrogen (N ₂₎ gas and / or their mixed gas, reducing gas, for example, hydrogen (H ₂₎ gas, ammonia (NH ₃₎ gas, and / Or a mixed gas thereof, but is not limited thereto.

In the present invention, the spinning material that is radiated in the high temperature region may be injected at a rate of 5 to 50 ml / hr, preferably at a rate of 5 to 40 ml / hr or 5 to 30 ml / hr or 5 to 20 ml / hr . The rate of injection of the spinning material may vary depending on the type of spinning material, the size of the reactor, and the like, as described above.

Another aspect of the present invention provides a method for producing a carbon nanotube aggregate using the apparatus for producing a carbon nanotube aggregate of the present invention. (A) reacting a spinning material and a carrier gas to form a carbon nanotube aggregate; And (b) winding the prepared carbon nanotube aggregate. The present invention also provides a method for producing a carbon nanotube aggregate. The respective configurations are the same as described above.

10a, 10b: inlet 11, 11a, 11b: reactor 12: heating means
13: exhaust port 14: winding means 15, 15a, 15b: carbon nanotube aggregate

Claims

A columnar reactor having a reaction zone;
An inlet for injecting a spinning material and carrier gas into the reaction zone of the body;
Heating means for heating the reaction region; And
And a discharge port installed at a lower end of the main body to discharge the carbon nanotube aggregate,
Wherein the horizontal cross-sectional aspect ratio of the columnar reactor is greater than 1 and less than or equal to 100.

The method according to claim 1,
Wherein the aspect ratio of the horizontal cross section of the columnar reactor is 2 to 20.

The method according to claim 1,
The columnar reactor
Wherein the carbon nanotube aggregate is a slit column reactor.

The method according to claim 1,
Wherein the horizontal cross section of the columnar reactor is elliptical or polygonal.

The method according to claim 1,
Wherein the carbon nanotube aggregate discharged from the outlet is a carbon nanotube fiber or a carbon nanotube mat.

The method according to claim 1,
Wherein the inlet further comprises a spinning material supply unit for supplying a spinning material, and a carrier gas supply unit for supplying a carrier gas.

The method according to claim 1,
Wherein the carbon nanotube aggregate outlet comprises winding means for collecting and collecting the carbon nanotube aggregate discharged from the lower end of the columnar reactor main body.

[Claim 7]
Wherein the winding means comprises at least one selected from a spindle, a reel, a drum, a bobbin, and a conveyor.

The method according to claim 1,
Wherein the inlet comprises an injection nozzle for injecting a spinning material and a dispersing plate for injecting a carrier gas.

The method according to claim 1,
Wherein the heating means is a heating furnace enclosing the reactor main body, and the reaction region is heated to 1,000 to 3,000 占 폚.

The method according to claim 1,
Wherein the spinning material is a catalyst precursor dispersed in a gaseous or liquid carbon compound.

The method of claim 11,
Wherein the spinning material further comprises a catalytic activator.

Claim 11
Wherein the catalyst precursor comprises at least one selected from the group consisting of metallocene including ferrocene, iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium and oxides thereof.

The method of claim 11,
The gaseous or liquid carbon compound may be at least one selected from the group consisting of methane, ethylene, acetylene, methyl acetylene, vinylacetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetic acid, diethyl ether, polyethylene glycol, ethyl formate, Wherein the carbon nanotube aggregate comprises at least one selected from the group consisting of hydrofluoric acid, hydrofluoric acid, hydrofluoric acid (THF), dimethylformamide (DMF), dichloromethane, hexane, benzene, carbon tetrachloride and pentane.

The method of claim 11,
Wherein the carrier gas is a hydrocarbon-based gas, an inert gas, a reducing gas, or a mixed gas thereof.